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1 | /* |
2 | * kernel/sched.c |
3 | * |
4 | * Kernel scheduler and related syscalls |
5 | * |
6 | * Copyright (C) 1991-2002 Linus Torvalds |
7 | * |
8 | * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and |
9 | * make semaphores SMP safe |
10 | * 1998-11-19 Implemented schedule_timeout() and related stuff |
11 | * by Andrea Arcangeli |
12 | * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: |
13 | * hybrid priority-list and round-robin design with |
14 | * an array-switch method of distributing timeslices |
15 | * and per-CPU runqueues. Cleanups and useful suggestions |
16 | * by Davide Libenzi, preemptible kernel bits by Robert Love. |
17 | * 2003-09-03 Interactivity tuning by Con Kolivas. |
18 | * 2004-04-02 Scheduler domains code by Nick Piggin |
19 | * 2007-04-15 Work begun on replacing all interactivity tuning with a |
20 | * fair scheduling design by Con Kolivas. |
21 | * 2007-05-05 Load balancing (smp-nice) and other improvements |
22 | * by Peter Williams |
23 | * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith |
24 | * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri |
25 | * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, |
26 | * Thomas Gleixner, Mike Kravetz |
27 | */ |
28 | |
29 | #include <linux/mm.h> |
30 | #include <linux/module.h> |
31 | #include <linux/nmi.h> |
32 | #include <linux/init.h> |
33 | #include <linux/uaccess.h> |
34 | #include <linux/highmem.h> |
35 | #include <linux/smp_lock.h> |
36 | #include <asm/mmu_context.h> |
37 | #include <linux/interrupt.h> |
38 | #include <linux/capability.h> |
39 | #include <linux/completion.h> |
40 | #include <linux/kernel_stat.h> |
41 | #include <linux/debug_locks.h> |
42 | #include <linux/perf_event.h> |
43 | #include <linux/security.h> |
44 | #include <linux/notifier.h> |
45 | #include <linux/profile.h> |
46 | #include <linux/freezer.h> |
47 | #include <linux/vmalloc.h> |
48 | #include <linux/blkdev.h> |
49 | #include <linux/delay.h> |
50 | #include <linux/pid_namespace.h> |
51 | #include <linux/smp.h> |
52 | #include <linux/threads.h> |
53 | #include <linux/timer.h> |
54 | #include <linux/rcupdate.h> |
55 | #include <linux/cpu.h> |
56 | #include <linux/cpuset.h> |
57 | #include <linux/percpu.h> |
58 | #include <linux/kthread.h> |
59 | #include <linux/proc_fs.h> |
60 | #include <linux/seq_file.h> |
61 | #include <linux/sysctl.h> |
62 | #include <linux/syscalls.h> |
63 | #include <linux/times.h> |
64 | #include <linux/tsacct_kern.h> |
65 | #include <linux/kprobes.h> |
66 | #include <linux/delayacct.h> |
67 | #include <linux/unistd.h> |
68 | #include <linux/pagemap.h> |
69 | #include <linux/hrtimer.h> |
70 | #include <linux/tick.h> |
71 | #include <linux/debugfs.h> |
72 | #include <linux/ctype.h> |
73 | #include <linux/ftrace.h> |
74 | |
75 | #include <asm/tlb.h> |
76 | #include <asm/irq_regs.h> |
77 | |
78 | #include "sched_cpupri.h" |
79 | |
80 | #define CREATE_TRACE_POINTS |
81 | #include <trace/events/sched.h> |
82 | |
83 | /* |
84 | * Convert user-nice values [ -20 ... 0 ... 19 ] |
85 | * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], |
86 | * and back. |
87 | */ |
88 | #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) |
89 | #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) |
90 | #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) |
91 | |
92 | /* |
93 | * 'User priority' is the nice value converted to something we |
94 | * can work with better when scaling various scheduler parameters, |
95 | * it's a [ 0 ... 39 ] range. |
96 | */ |
97 | #define USER_PRIO(p) ((p)-MAX_RT_PRIO) |
98 | #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) |
99 | #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) |
100 | |
101 | /* |
102 | * Helpers for converting nanosecond timing to jiffy resolution |
103 | */ |
104 | #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ)) |
105 | |
106 | #define NICE_0_LOAD SCHED_LOAD_SCALE |
107 | #define NICE_0_SHIFT SCHED_LOAD_SHIFT |
108 | |
109 | /* |
110 | * These are the 'tuning knobs' of the scheduler: |
111 | * |
112 | * default timeslice is 100 msecs (used only for SCHED_RR tasks). |
113 | * Timeslices get refilled after they expire. |
114 | */ |
115 | #define DEF_TIMESLICE (100 * HZ / 1000) |
116 | |
117 | /* |
118 | * single value that denotes runtime == period, ie unlimited time. |
119 | */ |
120 | #define RUNTIME_INF ((u64)~0ULL) |
121 | |
122 | static inline int rt_policy(int policy) |
123 | { |
124 | if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR)) |
125 | return 1; |
126 | return 0; |
127 | } |
128 | |
129 | static inline int task_has_rt_policy(struct task_struct *p) |
130 | { |
131 | return rt_policy(p->policy); |
132 | } |
133 | |
134 | /* |
135 | * This is the priority-queue data structure of the RT scheduling class: |
136 | */ |
137 | struct rt_prio_array { |
138 | DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ |
139 | struct list_head queue[MAX_RT_PRIO]; |
140 | }; |
141 | |
142 | struct rt_bandwidth { |
143 | /* nests inside the rq lock: */ |
144 | spinlock_t rt_runtime_lock; |
145 | ktime_t rt_period; |
146 | u64 rt_runtime; |
147 | struct hrtimer rt_period_timer; |
148 | }; |
149 | |
150 | static struct rt_bandwidth def_rt_bandwidth; |
151 | |
152 | static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun); |
153 | |
154 | static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer) |
155 | { |
156 | struct rt_bandwidth *rt_b = |
157 | container_of(timer, struct rt_bandwidth, rt_period_timer); |
158 | ktime_t now; |
159 | int overrun; |
160 | int idle = 0; |
161 | |
162 | for (;;) { |
163 | now = hrtimer_cb_get_time(timer); |
164 | overrun = hrtimer_forward(timer, now, rt_b->rt_period); |
165 | |
166 | if (!overrun) |
167 | break; |
168 | |
169 | idle = do_sched_rt_period_timer(rt_b, overrun); |
170 | } |
171 | |
172 | return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; |
173 | } |
174 | |
175 | static |
176 | void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime) |
177 | { |
178 | rt_b->rt_period = ns_to_ktime(period); |
179 | rt_b->rt_runtime = runtime; |
180 | |
181 | spin_lock_init(&rt_b->rt_runtime_lock); |
182 | |
183 | hrtimer_init(&rt_b->rt_period_timer, |
184 | CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
185 | rt_b->rt_period_timer.function = sched_rt_period_timer; |
186 | } |
187 | |
188 | static inline int rt_bandwidth_enabled(void) |
189 | { |
190 | return sysctl_sched_rt_runtime >= 0; |
191 | } |
192 | |
193 | static void start_rt_bandwidth(struct rt_bandwidth *rt_b) |
194 | { |
195 | ktime_t now; |
196 | |
197 | if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF) |
198 | return; |
199 | |
200 | if (hrtimer_active(&rt_b->rt_period_timer)) |
201 | return; |
202 | |
203 | spin_lock(&rt_b->rt_runtime_lock); |
204 | for (;;) { |
205 | unsigned long delta; |
206 | ktime_t soft, hard; |
207 | |
208 | if (hrtimer_active(&rt_b->rt_period_timer)) |
209 | break; |
210 | |
211 | now = hrtimer_cb_get_time(&rt_b->rt_period_timer); |
212 | hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period); |
213 | |
214 | soft = hrtimer_get_softexpires(&rt_b->rt_period_timer); |
215 | hard = hrtimer_get_expires(&rt_b->rt_period_timer); |
216 | delta = ktime_to_ns(ktime_sub(hard, soft)); |
217 | __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta, |
218 | HRTIMER_MODE_ABS_PINNED, 0); |
219 | } |
220 | spin_unlock(&rt_b->rt_runtime_lock); |
221 | } |
222 | |
223 | #ifdef CONFIG_RT_GROUP_SCHED |
224 | static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b) |
225 | { |
226 | hrtimer_cancel(&rt_b->rt_period_timer); |
227 | } |
228 | #endif |
229 | |
230 | /* |
231 | * sched_domains_mutex serializes calls to arch_init_sched_domains, |
232 | * detach_destroy_domains and partition_sched_domains. |
233 | */ |
234 | static DEFINE_MUTEX(sched_domains_mutex); |
235 | |
236 | #ifdef CONFIG_GROUP_SCHED |
237 | |
238 | #include <linux/cgroup.h> |
239 | |
240 | struct cfs_rq; |
241 | |
242 | static LIST_HEAD(task_groups); |
243 | |
244 | /* task group related information */ |
245 | struct task_group { |
246 | #ifdef CONFIG_CGROUP_SCHED |
247 | struct cgroup_subsys_state css; |
248 | #endif |
249 | |
250 | #ifdef CONFIG_USER_SCHED |
251 | uid_t uid; |
252 | #endif |
253 | |
254 | #ifdef CONFIG_FAIR_GROUP_SCHED |
255 | /* schedulable entities of this group on each cpu */ |
256 | struct sched_entity **se; |
257 | /* runqueue "owned" by this group on each cpu */ |
258 | struct cfs_rq **cfs_rq; |
259 | unsigned long shares; |
260 | #endif |
261 | |
262 | #ifdef CONFIG_RT_GROUP_SCHED |
263 | struct sched_rt_entity **rt_se; |
264 | struct rt_rq **rt_rq; |
265 | |
266 | struct rt_bandwidth rt_bandwidth; |
267 | #endif |
268 | |
269 | struct rcu_head rcu; |
270 | struct list_head list; |
271 | |
272 | struct task_group *parent; |
273 | struct list_head siblings; |
274 | struct list_head children; |
275 | }; |
276 | |
277 | #ifdef CONFIG_USER_SCHED |
278 | |
279 | /* Helper function to pass uid information to create_sched_user() */ |
280 | void set_tg_uid(struct user_struct *user) |
281 | { |
282 | user->tg->uid = user->uid; |
283 | } |
284 | |
285 | /* |
286 | * Root task group. |
287 | * Every UID task group (including init_task_group aka UID-0) will |
288 | * be a child to this group. |
289 | */ |
290 | struct task_group root_task_group; |
291 | |
292 | #ifdef CONFIG_FAIR_GROUP_SCHED |
293 | /* Default task group's sched entity on each cpu */ |
294 | static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); |
295 | /* Default task group's cfs_rq on each cpu */ |
296 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct cfs_rq, init_tg_cfs_rq); |
297 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
298 | |
299 | #ifdef CONFIG_RT_GROUP_SCHED |
300 | static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity); |
301 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct rt_rq, init_rt_rq); |
302 | #endif /* CONFIG_RT_GROUP_SCHED */ |
303 | #else /* !CONFIG_USER_SCHED */ |
304 | #define root_task_group init_task_group |
305 | #endif /* CONFIG_USER_SCHED */ |
306 | |
307 | /* task_group_lock serializes add/remove of task groups and also changes to |
308 | * a task group's cpu shares. |
309 | */ |
310 | static DEFINE_SPINLOCK(task_group_lock); |
311 | |
312 | #ifdef CONFIG_FAIR_GROUP_SCHED |
313 | |
314 | #ifdef CONFIG_SMP |
315 | static int root_task_group_empty(void) |
316 | { |
317 | return list_empty(&root_task_group.children); |
318 | } |
319 | #endif |
320 | |
321 | #ifdef CONFIG_USER_SCHED |
322 | # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD) |
323 | #else /* !CONFIG_USER_SCHED */ |
324 | # define INIT_TASK_GROUP_LOAD NICE_0_LOAD |
325 | #endif /* CONFIG_USER_SCHED */ |
326 | |
327 | /* |
328 | * A weight of 0 or 1 can cause arithmetics problems. |
329 | * A weight of a cfs_rq is the sum of weights of which entities |
330 | * are queued on this cfs_rq, so a weight of a entity should not be |
331 | * too large, so as the shares value of a task group. |
332 | * (The default weight is 1024 - so there's no practical |
333 | * limitation from this.) |
334 | */ |
335 | #define MIN_SHARES 2 |
336 | #define MAX_SHARES (1UL << 18) |
337 | |
338 | static int init_task_group_load = INIT_TASK_GROUP_LOAD; |
339 | #endif |
340 | |
341 | /* Default task group. |
342 | * Every task in system belong to this group at bootup. |
343 | */ |
344 | struct task_group init_task_group; |
345 | |
346 | /* return group to which a task belongs */ |
347 | static inline struct task_group *task_group(struct task_struct *p) |
348 | { |
349 | struct task_group *tg; |
350 | |
351 | #ifdef CONFIG_USER_SCHED |
352 | rcu_read_lock(); |
353 | tg = __task_cred(p)->user->tg; |
354 | rcu_read_unlock(); |
355 | #elif defined(CONFIG_CGROUP_SCHED) |
356 | tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id), |
357 | struct task_group, css); |
358 | #else |
359 | tg = &init_task_group; |
360 | #endif |
361 | return tg; |
362 | } |
363 | |
364 | /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */ |
365 | static inline void set_task_rq(struct task_struct *p, unsigned int cpu) |
366 | { |
367 | #ifdef CONFIG_FAIR_GROUP_SCHED |
368 | p->se.cfs_rq = task_group(p)->cfs_rq[cpu]; |
369 | p->se.parent = task_group(p)->se[cpu]; |
370 | #endif |
371 | |
372 | #ifdef CONFIG_RT_GROUP_SCHED |
373 | p->rt.rt_rq = task_group(p)->rt_rq[cpu]; |
374 | p->rt.parent = task_group(p)->rt_se[cpu]; |
375 | #endif |
376 | } |
377 | |
378 | #else |
379 | |
380 | static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { } |
381 | static inline struct task_group *task_group(struct task_struct *p) |
382 | { |
383 | return NULL; |
384 | } |
385 | |
386 | #endif /* CONFIG_GROUP_SCHED */ |
387 | |
388 | /* CFS-related fields in a runqueue */ |
389 | struct cfs_rq { |
390 | struct load_weight load; |
391 | unsigned long nr_running; |
392 | |
393 | u64 exec_clock; |
394 | u64 min_vruntime; |
395 | |
396 | struct rb_root tasks_timeline; |
397 | struct rb_node *rb_leftmost; |
398 | |
399 | struct list_head tasks; |
400 | struct list_head *balance_iterator; |
401 | |
402 | /* |
403 | * 'curr' points to currently running entity on this cfs_rq. |
404 | * It is set to NULL otherwise (i.e when none are currently running). |
405 | */ |
406 | struct sched_entity *curr, *next, *last; |
407 | |
408 | unsigned int nr_spread_over; |
409 | |
410 | #ifdef CONFIG_FAIR_GROUP_SCHED |
411 | struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ |
412 | |
413 | /* |
414 | * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in |
415 | * a hierarchy). Non-leaf lrqs hold other higher schedulable entities |
416 | * (like users, containers etc.) |
417 | * |
418 | * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This |
419 | * list is used during load balance. |
420 | */ |
421 | struct list_head leaf_cfs_rq_list; |
422 | struct task_group *tg; /* group that "owns" this runqueue */ |
423 | |
424 | #ifdef CONFIG_SMP |
425 | /* |
426 | * the part of load.weight contributed by tasks |
427 | */ |
428 | unsigned long task_weight; |
429 | |
430 | /* |
431 | * h_load = weight * f(tg) |
432 | * |
433 | * Where f(tg) is the recursive weight fraction assigned to |
434 | * this group. |
435 | */ |
436 | unsigned long h_load; |
437 | |
438 | /* |
439 | * this cpu's part of tg->shares |
440 | */ |
441 | unsigned long shares; |
442 | |
443 | /* |
444 | * load.weight at the time we set shares |
445 | */ |
446 | unsigned long rq_weight; |
447 | #endif |
448 | #endif |
449 | }; |
450 | |
451 | /* Real-Time classes' related field in a runqueue: */ |
452 | struct rt_rq { |
453 | struct rt_prio_array active; |
454 | unsigned long rt_nr_running; |
455 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
456 | struct { |
457 | int curr; /* highest queued rt task prio */ |
458 | #ifdef CONFIG_SMP |
459 | int next; /* next highest */ |
460 | #endif |
461 | } highest_prio; |
462 | #endif |
463 | #ifdef CONFIG_SMP |
464 | unsigned long rt_nr_migratory; |
465 | unsigned long rt_nr_total; |
466 | int overloaded; |
467 | struct plist_head pushable_tasks; |
468 | #endif |
469 | int rt_throttled; |
470 | u64 rt_time; |
471 | u64 rt_runtime; |
472 | /* Nests inside the rq lock: */ |
473 | spinlock_t rt_runtime_lock; |
474 | |
475 | #ifdef CONFIG_RT_GROUP_SCHED |
476 | unsigned long rt_nr_boosted; |
477 | |
478 | struct rq *rq; |
479 | struct list_head leaf_rt_rq_list; |
480 | struct task_group *tg; |
481 | struct sched_rt_entity *rt_se; |
482 | #endif |
483 | }; |
484 | |
485 | #ifdef CONFIG_SMP |
486 | |
487 | /* |
488 | * We add the notion of a root-domain which will be used to define per-domain |
489 | * variables. Each exclusive cpuset essentially defines an island domain by |
490 | * fully partitioning the member cpus from any other cpuset. Whenever a new |
491 | * exclusive cpuset is created, we also create and attach a new root-domain |
492 | * object. |
493 | * |
494 | */ |
495 | struct root_domain { |
496 | atomic_t refcount; |
497 | cpumask_var_t span; |
498 | cpumask_var_t online; |
499 | |
500 | /* |
501 | * The "RT overload" flag: it gets set if a CPU has more than |
502 | * one runnable RT task. |
503 | */ |
504 | cpumask_var_t rto_mask; |
505 | atomic_t rto_count; |
506 | #ifdef CONFIG_SMP |
507 | struct cpupri cpupri; |
508 | #endif |
509 | }; |
510 | |
511 | /* |
512 | * By default the system creates a single root-domain with all cpus as |
513 | * members (mimicking the global state we have today). |
514 | */ |
515 | static struct root_domain def_root_domain; |
516 | |
517 | #endif |
518 | |
519 | /* |
520 | * This is the main, per-CPU runqueue data structure. |
521 | * |
522 | * Locking rule: those places that want to lock multiple runqueues |
523 | * (such as the load balancing or the thread migration code), lock |
524 | * acquire operations must be ordered by ascending &runqueue. |
525 | */ |
526 | struct rq { |
527 | /* runqueue lock: */ |
528 | spinlock_t lock; |
529 | |
530 | /* |
531 | * nr_running and cpu_load should be in the same cacheline because |
532 | * remote CPUs use both these fields when doing load calculation. |
533 | */ |
534 | unsigned long nr_running; |
535 | #define CPU_LOAD_IDX_MAX 5 |
536 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; |
537 | #ifdef CONFIG_NO_HZ |
538 | unsigned long last_tick_seen; |
539 | unsigned char in_nohz_recently; |
540 | #endif |
541 | /* capture load from *all* tasks on this cpu: */ |
542 | struct load_weight load; |
543 | unsigned long nr_load_updates; |
544 | u64 nr_switches; |
545 | u64 nr_migrations_in; |
546 | |
547 | struct cfs_rq cfs; |
548 | struct rt_rq rt; |
549 | |
550 | #ifdef CONFIG_FAIR_GROUP_SCHED |
551 | /* list of leaf cfs_rq on this cpu: */ |
552 | struct list_head leaf_cfs_rq_list; |
553 | #endif |
554 | #ifdef CONFIG_RT_GROUP_SCHED |
555 | struct list_head leaf_rt_rq_list; |
556 | #endif |
557 | |
558 | /* |
559 | * This is part of a global counter where only the total sum |
560 | * over all CPUs matters. A task can increase this counter on |
561 | * one CPU and if it got migrated afterwards it may decrease |
562 | * it on another CPU. Always updated under the runqueue lock: |
563 | */ |
564 | unsigned long nr_uninterruptible; |
565 | |
566 | struct task_struct *curr, *idle; |
567 | unsigned long next_balance; |
568 | struct mm_struct *prev_mm; |
569 | |
570 | u64 clock; |
571 | |
572 | atomic_t nr_iowait; |
573 | |
574 | #ifdef CONFIG_SMP |
575 | struct root_domain *rd; |
576 | struct sched_domain *sd; |
577 | |
578 | unsigned char idle_at_tick; |
579 | /* For active balancing */ |
580 | int post_schedule; |
581 | int active_balance; |
582 | int push_cpu; |
583 | /* cpu of this runqueue: */ |
584 | int cpu; |
585 | int online; |
586 | |
587 | unsigned long avg_load_per_task; |
588 | |
589 | struct task_struct *migration_thread; |
590 | struct list_head migration_queue; |
591 | |
592 | u64 rt_avg; |
593 | u64 age_stamp; |
594 | u64 idle_stamp; |
595 | u64 avg_idle; |
596 | #endif |
597 | |
598 | /* calc_load related fields */ |
599 | unsigned long calc_load_update; |
600 | long calc_load_active; |
601 | |
602 | #ifdef CONFIG_SCHED_HRTICK |
603 | #ifdef CONFIG_SMP |
604 | int hrtick_csd_pending; |
605 | struct call_single_data hrtick_csd; |
606 | #endif |
607 | struct hrtimer hrtick_timer; |
608 | #endif |
609 | |
610 | #ifdef CONFIG_SCHEDSTATS |
611 | /* latency stats */ |
612 | struct sched_info rq_sched_info; |
613 | unsigned long long rq_cpu_time; |
614 | /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */ |
615 | |
616 | /* sys_sched_yield() stats */ |
617 | unsigned int yld_count; |
618 | |
619 | /* schedule() stats */ |
620 | unsigned int sched_switch; |
621 | unsigned int sched_count; |
622 | unsigned int sched_goidle; |
623 | |
624 | /* try_to_wake_up() stats */ |
625 | unsigned int ttwu_count; |
626 | unsigned int ttwu_local; |
627 | |
628 | /* BKL stats */ |
629 | unsigned int bkl_count; |
630 | #endif |
631 | }; |
632 | |
633 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
634 | |
635 | static inline |
636 | void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) |
637 | { |
638 | rq->curr->sched_class->check_preempt_curr(rq, p, flags); |
639 | } |
640 | |
641 | static inline int cpu_of(struct rq *rq) |
642 | { |
643 | #ifdef CONFIG_SMP |
644 | return rq->cpu; |
645 | #else |
646 | return 0; |
647 | #endif |
648 | } |
649 | |
650 | /* |
651 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. |
652 | * See detach_destroy_domains: synchronize_sched for details. |
653 | * |
654 | * The domain tree of any CPU may only be accessed from within |
655 | * preempt-disabled sections. |
656 | */ |
657 | #define for_each_domain(cpu, __sd) \ |
658 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) |
659 | |
660 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) |
661 | #define this_rq() (&__get_cpu_var(runqueues)) |
662 | #define task_rq(p) cpu_rq(task_cpu(p)) |
663 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) |
664 | #define raw_rq() (&__raw_get_cpu_var(runqueues)) |
665 | |
666 | inline void update_rq_clock(struct rq *rq) |
667 | { |
668 | rq->clock = sched_clock_cpu(cpu_of(rq)); |
669 | } |
670 | |
671 | /* |
672 | * Tunables that become constants when CONFIG_SCHED_DEBUG is off: |
673 | */ |
674 | #ifdef CONFIG_SCHED_DEBUG |
675 | # define const_debug __read_mostly |
676 | #else |
677 | # define const_debug static const |
678 | #endif |
679 | |
680 | /** |
681 | * runqueue_is_locked |
682 | * @cpu: the processor in question. |
683 | * |
684 | * Returns true if the current cpu runqueue is locked. |
685 | * This interface allows printk to be called with the runqueue lock |
686 | * held and know whether or not it is OK to wake up the klogd. |
687 | */ |
688 | int runqueue_is_locked(int cpu) |
689 | { |
690 | return spin_is_locked(&cpu_rq(cpu)->lock); |
691 | } |
692 | |
693 | /* |
694 | * Debugging: various feature bits |
695 | */ |
696 | |
697 | #define SCHED_FEAT(name, enabled) \ |
698 | __SCHED_FEAT_##name , |
699 | |
700 | enum { |
701 | #include "sched_features.h" |
702 | }; |
703 | |
704 | #undef SCHED_FEAT |
705 | |
706 | #define SCHED_FEAT(name, enabled) \ |
707 | (1UL << __SCHED_FEAT_##name) * enabled | |
708 | |
709 | const_debug unsigned int sysctl_sched_features = |
710 | #include "sched_features.h" |
711 | 0; |
712 | |
713 | #undef SCHED_FEAT |
714 | |
715 | #ifdef CONFIG_SCHED_DEBUG |
716 | #define SCHED_FEAT(name, enabled) \ |
717 | #name , |
718 | |
719 | static __read_mostly char *sched_feat_names[] = { |
720 | #include "sched_features.h" |
721 | NULL |
722 | }; |
723 | |
724 | #undef SCHED_FEAT |
725 | |
726 | static int sched_feat_show(struct seq_file *m, void *v) |
727 | { |
728 | int i; |
729 | |
730 | for (i = 0; sched_feat_names[i]; i++) { |
731 | if (!(sysctl_sched_features & (1UL << i))) |
732 | seq_puts(m, "NO_"); |
733 | seq_printf(m, "%s ", sched_feat_names[i]); |
734 | } |
735 | seq_puts(m, "\n"); |
736 | |
737 | return 0; |
738 | } |
739 | |
740 | static ssize_t |
741 | sched_feat_write(struct file *filp, const char __user *ubuf, |
742 | size_t cnt, loff_t *ppos) |
743 | { |
744 | char buf[64]; |
745 | char *cmp = buf; |
746 | int neg = 0; |
747 | int i; |
748 | |
749 | if (cnt > 63) |
750 | cnt = 63; |
751 | |
752 | if (copy_from_user(&buf, ubuf, cnt)) |
753 | return -EFAULT; |
754 | |
755 | buf[cnt] = 0; |
756 | |
757 | if (strncmp(buf, "NO_", 3) == 0) { |
758 | neg = 1; |
759 | cmp += 3; |
760 | } |
761 | |
762 | for (i = 0; sched_feat_names[i]; i++) { |
763 | int len = strlen(sched_feat_names[i]); |
764 | |
765 | if (strncmp(cmp, sched_feat_names[i], len) == 0) { |
766 | if (neg) |
767 | sysctl_sched_features &= ~(1UL << i); |
768 | else |
769 | sysctl_sched_features |= (1UL << i); |
770 | break; |
771 | } |
772 | } |
773 | |
774 | if (!sched_feat_names[i]) |
775 | return -EINVAL; |
776 | |
777 | filp->f_pos += cnt; |
778 | |
779 | return cnt; |
780 | } |
781 | |
782 | static int sched_feat_open(struct inode *inode, struct file *filp) |
783 | { |
784 | return single_open(filp, sched_feat_show, NULL); |
785 | } |
786 | |
787 | static const struct file_operations sched_feat_fops = { |
788 | .open = sched_feat_open, |
789 | .write = sched_feat_write, |
790 | .read = seq_read, |
791 | .llseek = seq_lseek, |
792 | .release = single_release, |
793 | }; |
794 | |
795 | static __init int sched_init_debug(void) |
796 | { |
797 | debugfs_create_file("sched_features", 0644, NULL, NULL, |
798 | &sched_feat_fops); |
799 | |
800 | return 0; |
801 | } |
802 | late_initcall(sched_init_debug); |
803 | |
804 | #endif |
805 | |
806 | #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) |
807 | |
808 | /* |
809 | * Number of tasks to iterate in a single balance run. |
810 | * Limited because this is done with IRQs disabled. |
811 | */ |
812 | const_debug unsigned int sysctl_sched_nr_migrate = 32; |
813 | |
814 | /* |
815 | * ratelimit for updating the group shares. |
816 | * default: 0.25ms |
817 | */ |
818 | unsigned int sysctl_sched_shares_ratelimit = 250000; |
819 | unsigned int normalized_sysctl_sched_shares_ratelimit = 250000; |
820 | |
821 | /* |
822 | * Inject some fuzzyness into changing the per-cpu group shares |
823 | * this avoids remote rq-locks at the expense of fairness. |
824 | * default: 4 |
825 | */ |
826 | unsigned int sysctl_sched_shares_thresh = 4; |
827 | |
828 | /* |
829 | * period over which we average the RT time consumption, measured |
830 | * in ms. |
831 | * |
832 | * default: 1s |
833 | */ |
834 | const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; |
835 | |
836 | /* |
837 | * period over which we measure -rt task cpu usage in us. |
838 | * default: 1s |
839 | */ |
840 | unsigned int sysctl_sched_rt_period = 1000000; |
841 | |
842 | static __read_mostly int scheduler_running; |
843 | |
844 | /* |
845 | * part of the period that we allow rt tasks to run in us. |
846 | * default: 0.95s |
847 | */ |
848 | int sysctl_sched_rt_runtime = 950000; |
849 | |
850 | static inline u64 global_rt_period(void) |
851 | { |
852 | return (u64)sysctl_sched_rt_period * NSEC_PER_USEC; |
853 | } |
854 | |
855 | static inline u64 global_rt_runtime(void) |
856 | { |
857 | if (sysctl_sched_rt_runtime < 0) |
858 | return RUNTIME_INF; |
859 | |
860 | return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC; |
861 | } |
862 | |
863 | #ifndef prepare_arch_switch |
864 | # define prepare_arch_switch(next) do { } while (0) |
865 | #endif |
866 | #ifndef finish_arch_switch |
867 | # define finish_arch_switch(prev) do { } while (0) |
868 | #endif |
869 | |
870 | static inline int task_current(struct rq *rq, struct task_struct *p) |
871 | { |
872 | return rq->curr == p; |
873 | } |
874 | |
875 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
876 | static inline int task_running(struct rq *rq, struct task_struct *p) |
877 | { |
878 | return task_current(rq, p); |
879 | } |
880 | |
881 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
882 | { |
883 | } |
884 | |
885 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
886 | { |
887 | #ifdef CONFIG_DEBUG_SPINLOCK |
888 | /* this is a valid case when another task releases the spinlock */ |
889 | rq->lock.owner = current; |
890 | #endif |
891 | /* |
892 | * If we are tracking spinlock dependencies then we have to |
893 | * fix up the runqueue lock - which gets 'carried over' from |
894 | * prev into current: |
895 | */ |
896 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); |
897 | |
898 | spin_unlock_irq(&rq->lock); |
899 | } |
900 | |
901 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ |
902 | static inline int task_running(struct rq *rq, struct task_struct *p) |
903 | { |
904 | #ifdef CONFIG_SMP |
905 | return p->oncpu; |
906 | #else |
907 | return task_current(rq, p); |
908 | #endif |
909 | } |
910 | |
911 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
912 | { |
913 | #ifdef CONFIG_SMP |
914 | /* |
915 | * We can optimise this out completely for !SMP, because the |
916 | * SMP rebalancing from interrupt is the only thing that cares |
917 | * here. |
918 | */ |
919 | next->oncpu = 1; |
920 | #endif |
921 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
922 | spin_unlock_irq(&rq->lock); |
923 | #else |
924 | spin_unlock(&rq->lock); |
925 | #endif |
926 | } |
927 | |
928 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
929 | { |
930 | #ifdef CONFIG_SMP |
931 | /* |
932 | * After ->oncpu is cleared, the task can be moved to a different CPU. |
933 | * We must ensure this doesn't happen until the switch is completely |
934 | * finished. |
935 | */ |
936 | smp_wmb(); |
937 | prev->oncpu = 0; |
938 | #endif |
939 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
940 | local_irq_enable(); |
941 | #endif |
942 | } |
943 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ |
944 | |
945 | /* |
946 | * __task_rq_lock - lock the runqueue a given task resides on. |
947 | * Must be called interrupts disabled. |
948 | */ |
949 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
950 | __acquires(rq->lock) |
951 | { |
952 | for (;;) { |
953 | struct rq *rq = task_rq(p); |
954 | spin_lock(&rq->lock); |
955 | if (likely(rq == task_rq(p))) |
956 | return rq; |
957 | spin_unlock(&rq->lock); |
958 | } |
959 | } |
960 | |
961 | /* |
962 | * task_rq_lock - lock the runqueue a given task resides on and disable |
963 | * interrupts. Note the ordering: we can safely lookup the task_rq without |
964 | * explicitly disabling preemption. |
965 | */ |
966 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
967 | __acquires(rq->lock) |
968 | { |
969 | struct rq *rq; |
970 | |
971 | for (;;) { |
972 | local_irq_save(*flags); |
973 | rq = task_rq(p); |
974 | spin_lock(&rq->lock); |
975 | if (likely(rq == task_rq(p))) |
976 | return rq; |
977 | spin_unlock_irqrestore(&rq->lock, *flags); |
978 | } |
979 | } |
980 | |
981 | void task_rq_unlock_wait(struct task_struct *p) |
982 | { |
983 | struct rq *rq = task_rq(p); |
984 | |
985 | smp_mb(); /* spin-unlock-wait is not a full memory barrier */ |
986 | spin_unlock_wait(&rq->lock); |
987 | } |
988 | |
989 | static void __task_rq_unlock(struct rq *rq) |
990 | __releases(rq->lock) |
991 | { |
992 | spin_unlock(&rq->lock); |
993 | } |
994 | |
995 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
996 | __releases(rq->lock) |
997 | { |
998 | spin_unlock_irqrestore(&rq->lock, *flags); |
999 | } |
1000 | |
1001 | /* |
1002 | * this_rq_lock - lock this runqueue and disable interrupts. |
1003 | */ |
1004 | static struct rq *this_rq_lock(void) |
1005 | __acquires(rq->lock) |
1006 | { |
1007 | struct rq *rq; |
1008 | |
1009 | local_irq_disable(); |
1010 | rq = this_rq(); |
1011 | spin_lock(&rq->lock); |
1012 | |
1013 | return rq; |
1014 | } |
1015 | |
1016 | #ifdef CONFIG_SCHED_HRTICK |
1017 | /* |
1018 | * Use HR-timers to deliver accurate preemption points. |
1019 | * |
1020 | * Its all a bit involved since we cannot program an hrt while holding the |
1021 | * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a |
1022 | * reschedule event. |
1023 | * |
1024 | * When we get rescheduled we reprogram the hrtick_timer outside of the |
1025 | * rq->lock. |
1026 | */ |
1027 | |
1028 | /* |
1029 | * Use hrtick when: |
1030 | * - enabled by features |
1031 | * - hrtimer is actually high res |
1032 | */ |
1033 | static inline int hrtick_enabled(struct rq *rq) |
1034 | { |
1035 | if (!sched_feat(HRTICK)) |
1036 | return 0; |
1037 | if (!cpu_active(cpu_of(rq))) |
1038 | return 0; |
1039 | return hrtimer_is_hres_active(&rq->hrtick_timer); |
1040 | } |
1041 | |
1042 | static void hrtick_clear(struct rq *rq) |
1043 | { |
1044 | if (hrtimer_active(&rq->hrtick_timer)) |
1045 | hrtimer_cancel(&rq->hrtick_timer); |
1046 | } |
1047 | |
1048 | /* |
1049 | * High-resolution timer tick. |
1050 | * Runs from hardirq context with interrupts disabled. |
1051 | */ |
1052 | static enum hrtimer_restart hrtick(struct hrtimer *timer) |
1053 | { |
1054 | struct rq *rq = container_of(timer, struct rq, hrtick_timer); |
1055 | |
1056 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); |
1057 | |
1058 | spin_lock(&rq->lock); |
1059 | update_rq_clock(rq); |
1060 | rq->curr->sched_class->task_tick(rq, rq->curr, 1); |
1061 | spin_unlock(&rq->lock); |
1062 | |
1063 | return HRTIMER_NORESTART; |
1064 | } |
1065 | |
1066 | #ifdef CONFIG_SMP |
1067 | /* |
1068 | * called from hardirq (IPI) context |
1069 | */ |
1070 | static void __hrtick_start(void *arg) |
1071 | { |
1072 | struct rq *rq = arg; |
1073 | |
1074 | spin_lock(&rq->lock); |
1075 | hrtimer_restart(&rq->hrtick_timer); |
1076 | rq->hrtick_csd_pending = 0; |
1077 | spin_unlock(&rq->lock); |
1078 | } |
1079 | |
1080 | /* |
1081 | * Called to set the hrtick timer state. |
1082 | * |
1083 | * called with rq->lock held and irqs disabled |
1084 | */ |
1085 | static void hrtick_start(struct rq *rq, u64 delay) |
1086 | { |
1087 | struct hrtimer *timer = &rq->hrtick_timer; |
1088 | ktime_t time = ktime_add_ns(timer->base->get_time(), delay); |
1089 | |
1090 | hrtimer_set_expires(timer, time); |
1091 | |
1092 | if (rq == this_rq()) { |
1093 | hrtimer_restart(timer); |
1094 | } else if (!rq->hrtick_csd_pending) { |
1095 | __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); |
1096 | rq->hrtick_csd_pending = 1; |
1097 | } |
1098 | } |
1099 | |
1100 | static int |
1101 | hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) |
1102 | { |
1103 | int cpu = (int)(long)hcpu; |
1104 | |
1105 | switch (action) { |
1106 | case CPU_UP_CANCELED: |
1107 | case CPU_UP_CANCELED_FROZEN: |
1108 | case CPU_DOWN_PREPARE: |
1109 | case CPU_DOWN_PREPARE_FROZEN: |
1110 | case CPU_DEAD: |
1111 | case CPU_DEAD_FROZEN: |
1112 | hrtick_clear(cpu_rq(cpu)); |
1113 | return NOTIFY_OK; |
1114 | } |
1115 | |
1116 | return NOTIFY_DONE; |
1117 | } |
1118 | |
1119 | static __init void init_hrtick(void) |
1120 | { |
1121 | hotcpu_notifier(hotplug_hrtick, 0); |
1122 | } |
1123 | #else |
1124 | /* |
1125 | * Called to set the hrtick timer state. |
1126 | * |
1127 | * called with rq->lock held and irqs disabled |
1128 | */ |
1129 | static void hrtick_start(struct rq *rq, u64 delay) |
1130 | { |
1131 | __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, |
1132 | HRTIMER_MODE_REL_PINNED, 0); |
1133 | } |
1134 | |
1135 | static inline void init_hrtick(void) |
1136 | { |
1137 | } |
1138 | #endif /* CONFIG_SMP */ |
1139 | |
1140 | static void init_rq_hrtick(struct rq *rq) |
1141 | { |
1142 | #ifdef CONFIG_SMP |
1143 | rq->hrtick_csd_pending = 0; |
1144 | |
1145 | rq->hrtick_csd.flags = 0; |
1146 | rq->hrtick_csd.func = __hrtick_start; |
1147 | rq->hrtick_csd.info = rq; |
1148 | #endif |
1149 | |
1150 | hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1151 | rq->hrtick_timer.function = hrtick; |
1152 | } |
1153 | #else /* CONFIG_SCHED_HRTICK */ |
1154 | static inline void hrtick_clear(struct rq *rq) |
1155 | { |
1156 | } |
1157 | |
1158 | static inline void init_rq_hrtick(struct rq *rq) |
1159 | { |
1160 | } |
1161 | |
1162 | static inline void init_hrtick(void) |
1163 | { |
1164 | } |
1165 | #endif /* CONFIG_SCHED_HRTICK */ |
1166 | |
1167 | /* |
1168 | * resched_task - mark a task 'to be rescheduled now'. |
1169 | * |
1170 | * On UP this means the setting of the need_resched flag, on SMP it |
1171 | * might also involve a cross-CPU call to trigger the scheduler on |
1172 | * the target CPU. |
1173 | */ |
1174 | #ifdef CONFIG_SMP |
1175 | |
1176 | #ifndef tsk_is_polling |
1177 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) |
1178 | #endif |
1179 | |
1180 | static void resched_task(struct task_struct *p) |
1181 | { |
1182 | int cpu; |
1183 | |
1184 | assert_spin_locked(&task_rq(p)->lock); |
1185 | |
1186 | if (test_tsk_need_resched(p)) |
1187 | return; |
1188 | |
1189 | set_tsk_need_resched(p); |
1190 | |
1191 | cpu = task_cpu(p); |
1192 | if (cpu == smp_processor_id()) |
1193 | return; |
1194 | |
1195 | /* NEED_RESCHED must be visible before we test polling */ |
1196 | smp_mb(); |
1197 | if (!tsk_is_polling(p)) |
1198 | smp_send_reschedule(cpu); |
1199 | } |
1200 | |
1201 | static void resched_cpu(int cpu) |
1202 | { |
1203 | struct rq *rq = cpu_rq(cpu); |
1204 | unsigned long flags; |
1205 | |
1206 | if (!spin_trylock_irqsave(&rq->lock, flags)) |
1207 | return; |
1208 | resched_task(cpu_curr(cpu)); |
1209 | spin_unlock_irqrestore(&rq->lock, flags); |
1210 | } |
1211 | |
1212 | #ifdef CONFIG_NO_HZ |
1213 | /* |
1214 | * When add_timer_on() enqueues a timer into the timer wheel of an |
1215 | * idle CPU then this timer might expire before the next timer event |
1216 | * which is scheduled to wake up that CPU. In case of a completely |
1217 | * idle system the next event might even be infinite time into the |
1218 | * future. wake_up_idle_cpu() ensures that the CPU is woken up and |
1219 | * leaves the inner idle loop so the newly added timer is taken into |
1220 | * account when the CPU goes back to idle and evaluates the timer |
1221 | * wheel for the next timer event. |
1222 | */ |
1223 | void wake_up_idle_cpu(int cpu) |
1224 | { |
1225 | struct rq *rq = cpu_rq(cpu); |
1226 | |
1227 | if (cpu == smp_processor_id()) |
1228 | return; |
1229 | |
1230 | /* |
1231 | * This is safe, as this function is called with the timer |
1232 | * wheel base lock of (cpu) held. When the CPU is on the way |
1233 | * to idle and has not yet set rq->curr to idle then it will |
1234 | * be serialized on the timer wheel base lock and take the new |
1235 | * timer into account automatically. |
1236 | */ |
1237 | if (rq->curr != rq->idle) |
1238 | return; |
1239 | |
1240 | /* |
1241 | * We can set TIF_RESCHED on the idle task of the other CPU |
1242 | * lockless. The worst case is that the other CPU runs the |
1243 | * idle task through an additional NOOP schedule() |
1244 | */ |
1245 | set_tsk_need_resched(rq->idle); |
1246 | |
1247 | /* NEED_RESCHED must be visible before we test polling */ |
1248 | smp_mb(); |
1249 | if (!tsk_is_polling(rq->idle)) |
1250 | smp_send_reschedule(cpu); |
1251 | } |
1252 | #endif /* CONFIG_NO_HZ */ |
1253 | |
1254 | static u64 sched_avg_period(void) |
1255 | { |
1256 | return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2; |
1257 | } |
1258 | |
1259 | static void sched_avg_update(struct rq *rq) |
1260 | { |
1261 | s64 period = sched_avg_period(); |
1262 | |
1263 | while ((s64)(rq->clock - rq->age_stamp) > period) { |
1264 | rq->age_stamp += period; |
1265 | rq->rt_avg /= 2; |
1266 | } |
1267 | } |
1268 | |
1269 | static void sched_rt_avg_update(struct rq *rq, u64 rt_delta) |
1270 | { |
1271 | rq->rt_avg += rt_delta; |
1272 | sched_avg_update(rq); |
1273 | } |
1274 | |
1275 | #else /* !CONFIG_SMP */ |
1276 | static void resched_task(struct task_struct *p) |
1277 | { |
1278 | assert_spin_locked(&task_rq(p)->lock); |
1279 | set_tsk_need_resched(p); |
1280 | } |
1281 | |
1282 | static void sched_rt_avg_update(struct rq *rq, u64 rt_delta) |
1283 | { |
1284 | } |
1285 | #endif /* CONFIG_SMP */ |
1286 | |
1287 | #if BITS_PER_LONG == 32 |
1288 | # define WMULT_CONST (~0UL) |
1289 | #else |
1290 | # define WMULT_CONST (1UL << 32) |
1291 | #endif |
1292 | |
1293 | #define WMULT_SHIFT 32 |
1294 | |
1295 | /* |
1296 | * Shift right and round: |
1297 | */ |
1298 | #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) |
1299 | |
1300 | /* |
1301 | * delta *= weight / lw |
1302 | */ |
1303 | static unsigned long |
1304 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
1305 | struct load_weight *lw) |
1306 | { |
1307 | u64 tmp; |
1308 | |
1309 | if (!lw->inv_weight) { |
1310 | if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST)) |
1311 | lw->inv_weight = 1; |
1312 | else |
1313 | lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2) |
1314 | / (lw->weight+1); |
1315 | } |
1316 | |
1317 | tmp = (u64)delta_exec * weight; |
1318 | /* |
1319 | * Check whether we'd overflow the 64-bit multiplication: |
1320 | */ |
1321 | if (unlikely(tmp > WMULT_CONST)) |
1322 | tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, |
1323 | WMULT_SHIFT/2); |
1324 | else |
1325 | tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); |
1326 | |
1327 | return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); |
1328 | } |
1329 | |
1330 | static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
1331 | { |
1332 | lw->weight += inc; |
1333 | lw->inv_weight = 0; |
1334 | } |
1335 | |
1336 | static inline void update_load_sub(struct load_weight *lw, unsigned long dec) |
1337 | { |
1338 | lw->weight -= dec; |
1339 | lw->inv_weight = 0; |
1340 | } |
1341 | |
1342 | /* |
1343 | * To aid in avoiding the subversion of "niceness" due to uneven distribution |
1344 | * of tasks with abnormal "nice" values across CPUs the contribution that |
1345 | * each task makes to its run queue's load is weighted according to its |
1346 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a |
1347 | * scaled version of the new time slice allocation that they receive on time |
1348 | * slice expiry etc. |
1349 | */ |
1350 | |
1351 | #define WEIGHT_IDLEPRIO 3 |
1352 | #define WMULT_IDLEPRIO 1431655765 |
1353 | |
1354 | /* |
1355 | * Nice levels are multiplicative, with a gentle 10% change for every |
1356 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to |
1357 | * nice 1, it will get ~10% less CPU time than another CPU-bound task |
1358 | * that remained on nice 0. |
1359 | * |
1360 | * The "10% effect" is relative and cumulative: from _any_ nice level, |
1361 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level |
1362 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. |
1363 | * If a task goes up by ~10% and another task goes down by ~10% then |
1364 | * the relative distance between them is ~25%.) |
1365 | */ |
1366 | static const int prio_to_weight[40] = { |
1367 | /* -20 */ 88761, 71755, 56483, 46273, 36291, |
1368 | /* -15 */ 29154, 23254, 18705, 14949, 11916, |
1369 | /* -10 */ 9548, 7620, 6100, 4904, 3906, |
1370 | /* -5 */ 3121, 2501, 1991, 1586, 1277, |
1371 | /* 0 */ 1024, 820, 655, 526, 423, |
1372 | /* 5 */ 335, 272, 215, 172, 137, |
1373 | /* 10 */ 110, 87, 70, 56, 45, |
1374 | /* 15 */ 36, 29, 23, 18, 15, |
1375 | }; |
1376 | |
1377 | /* |
1378 | * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. |
1379 | * |
1380 | * In cases where the weight does not change often, we can use the |
1381 | * precalculated inverse to speed up arithmetics by turning divisions |
1382 | * into multiplications: |
1383 | */ |
1384 | static const u32 prio_to_wmult[40] = { |
1385 | /* -20 */ 48388, 59856, 76040, 92818, 118348, |
1386 | /* -15 */ 147320, 184698, 229616, 287308, 360437, |
1387 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, |
1388 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, |
1389 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, |
1390 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, |
1391 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, |
1392 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, |
1393 | }; |
1394 | |
1395 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
1396 | |
1397 | /* |
1398 | * runqueue iterator, to support SMP load-balancing between different |
1399 | * scheduling classes, without having to expose their internal data |
1400 | * structures to the load-balancing proper: |
1401 | */ |
1402 | struct rq_iterator { |
1403 | void *arg; |
1404 | struct task_struct *(*start)(void *); |
1405 | struct task_struct *(*next)(void *); |
1406 | }; |
1407 | |
1408 | #ifdef CONFIG_SMP |
1409 | static unsigned long |
1410 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
1411 | unsigned long max_load_move, struct sched_domain *sd, |
1412 | enum cpu_idle_type idle, int *all_pinned, |
1413 | int *this_best_prio, struct rq_iterator *iterator); |
1414 | |
1415 | static int |
1416 | iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, |
1417 | struct sched_domain *sd, enum cpu_idle_type idle, |
1418 | struct rq_iterator *iterator); |
1419 | #endif |
1420 | |
1421 | /* Time spent by the tasks of the cpu accounting group executing in ... */ |
1422 | enum cpuacct_stat_index { |
1423 | CPUACCT_STAT_USER, /* ... user mode */ |
1424 | CPUACCT_STAT_SYSTEM, /* ... kernel mode */ |
1425 | |
1426 | CPUACCT_STAT_NSTATS, |
1427 | }; |
1428 | |
1429 | #ifdef CONFIG_CGROUP_CPUACCT |
1430 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime); |
1431 | static void cpuacct_update_stats(struct task_struct *tsk, |
1432 | enum cpuacct_stat_index idx, cputime_t val); |
1433 | #else |
1434 | static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} |
1435 | static inline void cpuacct_update_stats(struct task_struct *tsk, |
1436 | enum cpuacct_stat_index idx, cputime_t val) {} |
1437 | #endif |
1438 | |
1439 | static inline void inc_cpu_load(struct rq *rq, unsigned long load) |
1440 | { |
1441 | update_load_add(&rq->load, load); |
1442 | } |
1443 | |
1444 | static inline void dec_cpu_load(struct rq *rq, unsigned long load) |
1445 | { |
1446 | update_load_sub(&rq->load, load); |
1447 | } |
1448 | |
1449 | #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED) |
1450 | typedef int (*tg_visitor)(struct task_group *, void *); |
1451 | |
1452 | /* |
1453 | * Iterate the full tree, calling @down when first entering a node and @up when |
1454 | * leaving it for the final time. |
1455 | */ |
1456 | static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data) |
1457 | { |
1458 | struct task_group *parent, *child; |
1459 | int ret; |
1460 | |
1461 | rcu_read_lock(); |
1462 | parent = &root_task_group; |
1463 | down: |
1464 | ret = (*down)(parent, data); |
1465 | if (ret) |
1466 | goto out_unlock; |
1467 | list_for_each_entry_rcu(child, &parent->children, siblings) { |
1468 | parent = child; |
1469 | goto down; |
1470 | |
1471 | up: |
1472 | continue; |
1473 | } |
1474 | ret = (*up)(parent, data); |
1475 | if (ret) |
1476 | goto out_unlock; |
1477 | |
1478 | child = parent; |
1479 | parent = parent->parent; |
1480 | if (parent) |
1481 | goto up; |
1482 | out_unlock: |
1483 | rcu_read_unlock(); |
1484 | |
1485 | return ret; |
1486 | } |
1487 | |
1488 | static int tg_nop(struct task_group *tg, void *data) |
1489 | { |
1490 | return 0; |
1491 | } |
1492 | #endif |
1493 | |
1494 | #ifdef CONFIG_SMP |
1495 | /* Used instead of source_load when we know the type == 0 */ |
1496 | static unsigned long weighted_cpuload(const int cpu) |
1497 | { |
1498 | return cpu_rq(cpu)->load.weight; |
1499 | } |
1500 | |
1501 | /* |
1502 | * Return a low guess at the load of a migration-source cpu weighted |
1503 | * according to the scheduling class and "nice" value. |
1504 | * |
1505 | * We want to under-estimate the load of migration sources, to |
1506 | * balance conservatively. |
1507 | */ |
1508 | static unsigned long source_load(int cpu, int type) |
1509 | { |
1510 | struct rq *rq = cpu_rq(cpu); |
1511 | unsigned long total = weighted_cpuload(cpu); |
1512 | |
1513 | if (type == 0 || !sched_feat(LB_BIAS)) |
1514 | return total; |
1515 | |
1516 | return min(rq->cpu_load[type-1], total); |
1517 | } |
1518 | |
1519 | /* |
1520 | * Return a high guess at the load of a migration-target cpu weighted |
1521 | * according to the scheduling class and "nice" value. |
1522 | */ |
1523 | static unsigned long target_load(int cpu, int type) |
1524 | { |
1525 | struct rq *rq = cpu_rq(cpu); |
1526 | unsigned long total = weighted_cpuload(cpu); |
1527 | |
1528 | if (type == 0 || !sched_feat(LB_BIAS)) |
1529 | return total; |
1530 | |
1531 | return max(rq->cpu_load[type-1], total); |
1532 | } |
1533 | |
1534 | static struct sched_group *group_of(int cpu) |
1535 | { |
1536 | struct sched_domain *sd = rcu_dereference(cpu_rq(cpu)->sd); |
1537 | |
1538 | if (!sd) |
1539 | return NULL; |
1540 | |
1541 | return sd->groups; |
1542 | } |
1543 | |
1544 | static unsigned long power_of(int cpu) |
1545 | { |
1546 | struct sched_group *group = group_of(cpu); |
1547 | |
1548 | if (!group) |
1549 | return SCHED_LOAD_SCALE; |
1550 | |
1551 | return group->cpu_power; |
1552 | } |
1553 | |
1554 | static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); |
1555 | |
1556 | static unsigned long cpu_avg_load_per_task(int cpu) |
1557 | { |
1558 | struct rq *rq = cpu_rq(cpu); |
1559 | unsigned long nr_running = ACCESS_ONCE(rq->nr_running); |
1560 | |
1561 | if (nr_running) |
1562 | rq->avg_load_per_task = rq->load.weight / nr_running; |
1563 | else |
1564 | rq->avg_load_per_task = 0; |
1565 | |
1566 | return rq->avg_load_per_task; |
1567 | } |
1568 | |
1569 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1570 | |
1571 | static __read_mostly unsigned long *update_shares_data; |
1572 | |
1573 | static void __set_se_shares(struct sched_entity *se, unsigned long shares); |
1574 | |
1575 | /* |
1576 | * Calculate and set the cpu's group shares. |
1577 | */ |
1578 | static void update_group_shares_cpu(struct task_group *tg, int cpu, |
1579 | unsigned long sd_shares, |
1580 | unsigned long sd_rq_weight, |
1581 | unsigned long *usd_rq_weight) |
1582 | { |
1583 | unsigned long shares, rq_weight; |
1584 | int boost = 0; |
1585 | |
1586 | rq_weight = usd_rq_weight[cpu]; |
1587 | if (!rq_weight) { |
1588 | boost = 1; |
1589 | rq_weight = NICE_0_LOAD; |
1590 | } |
1591 | |
1592 | /* |
1593 | * \Sum_j shares_j * rq_weight_i |
1594 | * shares_i = ----------------------------- |
1595 | * \Sum_j rq_weight_j |
1596 | */ |
1597 | shares = (sd_shares * rq_weight) / sd_rq_weight; |
1598 | shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES); |
1599 | |
1600 | if (abs(shares - tg->se[cpu]->load.weight) > |
1601 | sysctl_sched_shares_thresh) { |
1602 | struct rq *rq = cpu_rq(cpu); |
1603 | unsigned long flags; |
1604 | |
1605 | spin_lock_irqsave(&rq->lock, flags); |
1606 | tg->cfs_rq[cpu]->rq_weight = boost ? 0 : rq_weight; |
1607 | tg->cfs_rq[cpu]->shares = boost ? 0 : shares; |
1608 | __set_se_shares(tg->se[cpu], shares); |
1609 | spin_unlock_irqrestore(&rq->lock, flags); |
1610 | } |
1611 | } |
1612 | |
1613 | /* |
1614 | * Re-compute the task group their per cpu shares over the given domain. |
1615 | * This needs to be done in a bottom-up fashion because the rq weight of a |
1616 | * parent group depends on the shares of its child groups. |
1617 | */ |
1618 | static int tg_shares_up(struct task_group *tg, void *data) |
1619 | { |
1620 | unsigned long weight, rq_weight = 0, shares = 0; |
1621 | unsigned long *usd_rq_weight; |
1622 | struct sched_domain *sd = data; |
1623 | unsigned long flags; |
1624 | int i; |
1625 | |
1626 | if (!tg->se[0]) |
1627 | return 0; |
1628 | |
1629 | local_irq_save(flags); |
1630 | usd_rq_weight = per_cpu_ptr(update_shares_data, smp_processor_id()); |
1631 | |
1632 | for_each_cpu(i, sched_domain_span(sd)) { |
1633 | weight = tg->cfs_rq[i]->load.weight; |
1634 | usd_rq_weight[i] = weight; |
1635 | |
1636 | /* |
1637 | * If there are currently no tasks on the cpu pretend there |
1638 | * is one of average load so that when a new task gets to |
1639 | * run here it will not get delayed by group starvation. |
1640 | */ |
1641 | if (!weight) |
1642 | weight = NICE_0_LOAD; |
1643 | |
1644 | rq_weight += weight; |
1645 | shares += tg->cfs_rq[i]->shares; |
1646 | } |
1647 | |
1648 | if ((!shares && rq_weight) || shares > tg->shares) |
1649 | shares = tg->shares; |
1650 | |
1651 | if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) |
1652 | shares = tg->shares; |
1653 | |
1654 | for_each_cpu(i, sched_domain_span(sd)) |
1655 | update_group_shares_cpu(tg, i, shares, rq_weight, usd_rq_weight); |
1656 | |
1657 | local_irq_restore(flags); |
1658 | |
1659 | return 0; |
1660 | } |
1661 | |
1662 | /* |
1663 | * Compute the cpu's hierarchical load factor for each task group. |
1664 | * This needs to be done in a top-down fashion because the load of a child |
1665 | * group is a fraction of its parents load. |
1666 | */ |
1667 | static int tg_load_down(struct task_group *tg, void *data) |
1668 | { |
1669 | unsigned long load; |
1670 | long cpu = (long)data; |
1671 | |
1672 | if (!tg->parent) { |
1673 | load = cpu_rq(cpu)->load.weight; |
1674 | } else { |
1675 | load = tg->parent->cfs_rq[cpu]->h_load; |
1676 | load *= tg->cfs_rq[cpu]->shares; |
1677 | load /= tg->parent->cfs_rq[cpu]->load.weight + 1; |
1678 | } |
1679 | |
1680 | tg->cfs_rq[cpu]->h_load = load; |
1681 | |
1682 | return 0; |
1683 | } |
1684 | |
1685 | static void update_shares(struct sched_domain *sd) |
1686 | { |
1687 | s64 elapsed; |
1688 | u64 now; |
1689 | |
1690 | if (root_task_group_empty()) |
1691 | return; |
1692 | |
1693 | now = cpu_clock(raw_smp_processor_id()); |
1694 | elapsed = now - sd->last_update; |
1695 | |
1696 | if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) { |
1697 | sd->last_update = now; |
1698 | walk_tg_tree(tg_nop, tg_shares_up, sd); |
1699 | } |
1700 | } |
1701 | |
1702 | static void update_shares_locked(struct rq *rq, struct sched_domain *sd) |
1703 | { |
1704 | if (root_task_group_empty()) |
1705 | return; |
1706 | |
1707 | spin_unlock(&rq->lock); |
1708 | update_shares(sd); |
1709 | spin_lock(&rq->lock); |
1710 | } |
1711 | |
1712 | static void update_h_load(long cpu) |
1713 | { |
1714 | if (root_task_group_empty()) |
1715 | return; |
1716 | |
1717 | walk_tg_tree(tg_load_down, tg_nop, (void *)cpu); |
1718 | } |
1719 | |
1720 | #else |
1721 | |
1722 | static inline void update_shares(struct sched_domain *sd) |
1723 | { |
1724 | } |
1725 | |
1726 | static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd) |
1727 | { |
1728 | } |
1729 | |
1730 | #endif |
1731 | |
1732 | #ifdef CONFIG_PREEMPT |
1733 | |
1734 | static void double_rq_lock(struct rq *rq1, struct rq *rq2); |
1735 | |
1736 | /* |
1737 | * fair double_lock_balance: Safely acquires both rq->locks in a fair |
1738 | * way at the expense of forcing extra atomic operations in all |
1739 | * invocations. This assures that the double_lock is acquired using the |
1740 | * same underlying policy as the spinlock_t on this architecture, which |
1741 | * reduces latency compared to the unfair variant below. However, it |
1742 | * also adds more overhead and therefore may reduce throughput. |
1743 | */ |
1744 | static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1745 | __releases(this_rq->lock) |
1746 | __acquires(busiest->lock) |
1747 | __acquires(this_rq->lock) |
1748 | { |
1749 | spin_unlock(&this_rq->lock); |
1750 | double_rq_lock(this_rq, busiest); |
1751 | |
1752 | return 1; |
1753 | } |
1754 | |
1755 | #else |
1756 | /* |
1757 | * Unfair double_lock_balance: Optimizes throughput at the expense of |
1758 | * latency by eliminating extra atomic operations when the locks are |
1759 | * already in proper order on entry. This favors lower cpu-ids and will |
1760 | * grant the double lock to lower cpus over higher ids under contention, |
1761 | * regardless of entry order into the function. |
1762 | */ |
1763 | static int _double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1764 | __releases(this_rq->lock) |
1765 | __acquires(busiest->lock) |
1766 | __acquires(this_rq->lock) |
1767 | { |
1768 | int ret = 0; |
1769 | |
1770 | if (unlikely(!spin_trylock(&busiest->lock))) { |
1771 | if (busiest < this_rq) { |
1772 | spin_unlock(&this_rq->lock); |
1773 | spin_lock(&busiest->lock); |
1774 | spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING); |
1775 | ret = 1; |
1776 | } else |
1777 | spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING); |
1778 | } |
1779 | return ret; |
1780 | } |
1781 | |
1782 | #endif /* CONFIG_PREEMPT */ |
1783 | |
1784 | /* |
1785 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. |
1786 | */ |
1787 | static int double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1788 | { |
1789 | if (unlikely(!irqs_disabled())) { |
1790 | /* printk() doesn't work good under rq->lock */ |
1791 | spin_unlock(&this_rq->lock); |
1792 | BUG_ON(1); |
1793 | } |
1794 | |
1795 | return _double_lock_balance(this_rq, busiest); |
1796 | } |
1797 | |
1798 | static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest) |
1799 | __releases(busiest->lock) |
1800 | { |
1801 | spin_unlock(&busiest->lock); |
1802 | lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_); |
1803 | } |
1804 | #endif |
1805 | |
1806 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1807 | static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) |
1808 | { |
1809 | #ifdef CONFIG_SMP |
1810 | cfs_rq->shares = shares; |
1811 | #endif |
1812 | } |
1813 | #endif |
1814 | |
1815 | static void calc_load_account_active(struct rq *this_rq); |
1816 | static void update_sysctl(void); |
1817 | |
1818 | #include "sched_stats.h" |
1819 | #include "sched_idletask.c" |
1820 | #include "sched_fair.c" |
1821 | #include "sched_rt.c" |
1822 | #ifdef CONFIG_SCHED_DEBUG |
1823 | # include "sched_debug.c" |
1824 | #endif |
1825 | |
1826 | #define sched_class_highest (&rt_sched_class) |
1827 | #define for_each_class(class) \ |
1828 | for (class = sched_class_highest; class; class = class->next) |
1829 | |
1830 | static void inc_nr_running(struct rq *rq) |
1831 | { |
1832 | rq->nr_running++; |
1833 | } |
1834 | |
1835 | static void dec_nr_running(struct rq *rq) |
1836 | { |
1837 | rq->nr_running--; |
1838 | } |
1839 | |
1840 | static void set_load_weight(struct task_struct *p) |
1841 | { |
1842 | if (task_has_rt_policy(p)) { |
1843 | p->se.load.weight = prio_to_weight[0] * 2; |
1844 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; |
1845 | return; |
1846 | } |
1847 | |
1848 | /* |
1849 | * SCHED_IDLE tasks get minimal weight: |
1850 | */ |
1851 | if (p->policy == SCHED_IDLE) { |
1852 | p->se.load.weight = WEIGHT_IDLEPRIO; |
1853 | p->se.load.inv_weight = WMULT_IDLEPRIO; |
1854 | return; |
1855 | } |
1856 | |
1857 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
1858 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; |
1859 | } |
1860 | |
1861 | static void update_avg(u64 *avg, u64 sample) |
1862 | { |
1863 | s64 diff = sample - *avg; |
1864 | *avg += diff >> 3; |
1865 | } |
1866 | |
1867 | static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) |
1868 | { |
1869 | if (wakeup) |
1870 | p->se.start_runtime = p->se.sum_exec_runtime; |
1871 | |
1872 | sched_info_queued(p); |
1873 | p->sched_class->enqueue_task(rq, p, wakeup); |
1874 | p->se.on_rq = 1; |
1875 | } |
1876 | |
1877 | static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) |
1878 | { |
1879 | if (sleep) { |
1880 | if (p->se.last_wakeup) { |
1881 | update_avg(&p->se.avg_overlap, |
1882 | p->se.sum_exec_runtime - p->se.last_wakeup); |
1883 | p->se.last_wakeup = 0; |
1884 | } else { |
1885 | update_avg(&p->se.avg_wakeup, |
1886 | sysctl_sched_wakeup_granularity); |
1887 | } |
1888 | } |
1889 | |
1890 | sched_info_dequeued(p); |
1891 | p->sched_class->dequeue_task(rq, p, sleep); |
1892 | p->se.on_rq = 0; |
1893 | } |
1894 | |
1895 | /* |
1896 | * __normal_prio - return the priority that is based on the static prio |
1897 | */ |
1898 | static inline int __normal_prio(struct task_struct *p) |
1899 | { |
1900 | return p->static_prio; |
1901 | } |
1902 | |
1903 | /* |
1904 | * Calculate the expected normal priority: i.e. priority |
1905 | * without taking RT-inheritance into account. Might be |
1906 | * boosted by interactivity modifiers. Changes upon fork, |
1907 | * setprio syscalls, and whenever the interactivity |
1908 | * estimator recalculates. |
1909 | */ |
1910 | static inline int normal_prio(struct task_struct *p) |
1911 | { |
1912 | int prio; |
1913 | |
1914 | if (task_has_rt_policy(p)) |
1915 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
1916 | else |
1917 | prio = __normal_prio(p); |
1918 | return prio; |
1919 | } |
1920 | |
1921 | /* |
1922 | * Calculate the current priority, i.e. the priority |
1923 | * taken into account by the scheduler. This value might |
1924 | * be boosted by RT tasks, or might be boosted by |
1925 | * interactivity modifiers. Will be RT if the task got |
1926 | * RT-boosted. If not then it returns p->normal_prio. |
1927 | */ |
1928 | static int effective_prio(struct task_struct *p) |
1929 | { |
1930 | p->normal_prio = normal_prio(p); |
1931 | /* |
1932 | * If we are RT tasks or we were boosted to RT priority, |
1933 | * keep the priority unchanged. Otherwise, update priority |
1934 | * to the normal priority: |
1935 | */ |
1936 | if (!rt_prio(p->prio)) |
1937 | return p->normal_prio; |
1938 | return p->prio; |
1939 | } |
1940 | |
1941 | /* |
1942 | * activate_task - move a task to the runqueue. |
1943 | */ |
1944 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1945 | { |
1946 | if (task_contributes_to_load(p)) |
1947 | rq->nr_uninterruptible--; |
1948 | |
1949 | enqueue_task(rq, p, wakeup); |
1950 | inc_nr_running(rq); |
1951 | } |
1952 | |
1953 | /* |
1954 | * deactivate_task - remove a task from the runqueue. |
1955 | */ |
1956 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1957 | { |
1958 | if (task_contributes_to_load(p)) |
1959 | rq->nr_uninterruptible++; |
1960 | |
1961 | dequeue_task(rq, p, sleep); |
1962 | dec_nr_running(rq); |
1963 | } |
1964 | |
1965 | /** |
1966 | * task_curr - is this task currently executing on a CPU? |
1967 | * @p: the task in question. |
1968 | */ |
1969 | inline int task_curr(const struct task_struct *p) |
1970 | { |
1971 | return cpu_curr(task_cpu(p)) == p; |
1972 | } |
1973 | |
1974 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) |
1975 | { |
1976 | set_task_rq(p, cpu); |
1977 | #ifdef CONFIG_SMP |
1978 | /* |
1979 | * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be |
1980 | * successfuly executed on another CPU. We must ensure that updates of |
1981 | * per-task data have been completed by this moment. |
1982 | */ |
1983 | smp_wmb(); |
1984 | task_thread_info(p)->cpu = cpu; |
1985 | #endif |
1986 | } |
1987 | |
1988 | static inline void check_class_changed(struct rq *rq, struct task_struct *p, |
1989 | const struct sched_class *prev_class, |
1990 | int oldprio, int running) |
1991 | { |
1992 | if (prev_class != p->sched_class) { |
1993 | if (prev_class->switched_from) |
1994 | prev_class->switched_from(rq, p, running); |
1995 | p->sched_class->switched_to(rq, p, running); |
1996 | } else |
1997 | p->sched_class->prio_changed(rq, p, oldprio, running); |
1998 | } |
1999 | |
2000 | /** |
2001 | * kthread_bind - bind a just-created kthread to a cpu. |
2002 | * @p: thread created by kthread_create(). |
2003 | * @cpu: cpu (might not be online, must be possible) for @k to run on. |
2004 | * |
2005 | * Description: This function is equivalent to set_cpus_allowed(), |
2006 | * except that @cpu doesn't need to be online, and the thread must be |
2007 | * stopped (i.e., just returned from kthread_create()). |
2008 | * |
2009 | * Function lives here instead of kthread.c because it messes with |
2010 | * scheduler internals which require locking. |
2011 | */ |
2012 | void kthread_bind(struct task_struct *p, unsigned int cpu) |
2013 | { |
2014 | struct rq *rq = cpu_rq(cpu); |
2015 | unsigned long flags; |
2016 | |
2017 | /* Must have done schedule() in kthread() before we set_task_cpu */ |
2018 | if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE)) { |
2019 | WARN_ON(1); |
2020 | return; |
2021 | } |
2022 | |
2023 | spin_lock_irqsave(&rq->lock, flags); |
2024 | set_task_cpu(p, cpu); |
2025 | p->cpus_allowed = cpumask_of_cpu(cpu); |
2026 | p->rt.nr_cpus_allowed = 1; |
2027 | p->flags |= PF_THREAD_BOUND; |
2028 | spin_unlock_irqrestore(&rq->lock, flags); |
2029 | } |
2030 | EXPORT_SYMBOL(kthread_bind); |
2031 | |
2032 | #ifdef CONFIG_SMP |
2033 | /* |
2034 | * Is this task likely cache-hot: |
2035 | */ |
2036 | static int |
2037 | task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) |
2038 | { |
2039 | s64 delta; |
2040 | |
2041 | if (p->sched_class != &fair_sched_class) |
2042 | return 0; |
2043 | |
2044 | /* |
2045 | * Buddy candidates are cache hot: |
2046 | */ |
2047 | if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running && |
2048 | (&p->se == cfs_rq_of(&p->se)->next || |
2049 | &p->se == cfs_rq_of(&p->se)->last)) |
2050 | return 1; |
2051 | |
2052 | if (sysctl_sched_migration_cost == -1) |
2053 | return 1; |
2054 | if (sysctl_sched_migration_cost == 0) |
2055 | return 0; |
2056 | |
2057 | delta = now - p->se.exec_start; |
2058 | |
2059 | return delta < (s64)sysctl_sched_migration_cost; |
2060 | } |
2061 | |
2062 | |
2063 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
2064 | { |
2065 | int old_cpu = task_cpu(p); |
2066 | struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); |
2067 | struct cfs_rq *old_cfsrq = task_cfs_rq(p), |
2068 | *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); |
2069 | u64 clock_offset; |
2070 | |
2071 | clock_offset = old_rq->clock - new_rq->clock; |
2072 | |
2073 | trace_sched_migrate_task(p, new_cpu); |
2074 | |
2075 | #ifdef CONFIG_SCHEDSTATS |
2076 | if (p->se.wait_start) |
2077 | p->se.wait_start -= clock_offset; |
2078 | if (p->se.sleep_start) |
2079 | p->se.sleep_start -= clock_offset; |
2080 | if (p->se.block_start) |
2081 | p->se.block_start -= clock_offset; |
2082 | #endif |
2083 | if (old_cpu != new_cpu) { |
2084 | p->se.nr_migrations++; |
2085 | new_rq->nr_migrations_in++; |
2086 | #ifdef CONFIG_SCHEDSTATS |
2087 | if (task_hot(p, old_rq->clock, NULL)) |
2088 | schedstat_inc(p, se.nr_forced2_migrations); |
2089 | #endif |
2090 | perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, |
2091 | 1, 1, NULL, 0); |
2092 | } |
2093 | p->se.vruntime -= old_cfsrq->min_vruntime - |
2094 | new_cfsrq->min_vruntime; |
2095 | |
2096 | __set_task_cpu(p, new_cpu); |
2097 | } |
2098 | |
2099 | struct migration_req { |
2100 | struct list_head list; |
2101 | |
2102 | struct task_struct *task; |
2103 | int dest_cpu; |
2104 | |
2105 | struct completion done; |
2106 | }; |
2107 | |
2108 | /* |
2109 | * The task's runqueue lock must be held. |
2110 | * Returns true if you have to wait for migration thread. |
2111 | */ |
2112 | static int |
2113 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
2114 | { |
2115 | struct rq *rq = task_rq(p); |
2116 | |
2117 | /* |
2118 | * If the task is not on a runqueue (and not running), then |
2119 | * it is sufficient to simply update the task's cpu field. |
2120 | */ |
2121 | if (!p->se.on_rq && !task_running(rq, p)) { |
2122 | set_task_cpu(p, dest_cpu); |
2123 | return 0; |
2124 | } |
2125 | |
2126 | init_completion(&req->done); |
2127 | req->task = p; |
2128 | req->dest_cpu = dest_cpu; |
2129 | list_add(&req->list, &rq->migration_queue); |
2130 | |
2131 | return 1; |
2132 | } |
2133 | |
2134 | /* |
2135 | * wait_task_context_switch - wait for a thread to complete at least one |
2136 | * context switch. |
2137 | * |
2138 | * @p must not be current. |
2139 | */ |
2140 | void wait_task_context_switch(struct task_struct *p) |
2141 | { |
2142 | unsigned long nvcsw, nivcsw, flags; |
2143 | int running; |
2144 | struct rq *rq; |
2145 | |
2146 | nvcsw = p->nvcsw; |
2147 | nivcsw = p->nivcsw; |
2148 | for (;;) { |
2149 | /* |
2150 | * The runqueue is assigned before the actual context |
2151 | * switch. We need to take the runqueue lock. |
2152 | * |
2153 | * We could check initially without the lock but it is |
2154 | * very likely that we need to take the lock in every |
2155 | * iteration. |
2156 | */ |
2157 | rq = task_rq_lock(p, &flags); |
2158 | running = task_running(rq, p); |
2159 | task_rq_unlock(rq, &flags); |
2160 | |
2161 | if (likely(!running)) |
2162 | break; |
2163 | /* |
2164 | * The switch count is incremented before the actual |
2165 | * context switch. We thus wait for two switches to be |
2166 | * sure at least one completed. |
2167 | */ |
2168 | if ((p->nvcsw - nvcsw) > 1) |
2169 | break; |
2170 | if ((p->nivcsw - nivcsw) > 1) |
2171 | break; |
2172 | |
2173 | cpu_relax(); |
2174 | } |
2175 | } |
2176 | |
2177 | /* |
2178 | * wait_task_inactive - wait for a thread to unschedule. |
2179 | * |
2180 | * If @match_state is nonzero, it's the @p->state value just checked and |
2181 | * not expected to change. If it changes, i.e. @p might have woken up, |
2182 | * then return zero. When we succeed in waiting for @p to be off its CPU, |
2183 | * we return a positive number (its total switch count). If a second call |
2184 | * a short while later returns the same number, the caller can be sure that |
2185 | * @p has remained unscheduled the whole time. |
2186 | * |
2187 | * The caller must ensure that the task *will* unschedule sometime soon, |
2188 | * else this function might spin for a *long* time. This function can't |
2189 | * be called with interrupts off, or it may introduce deadlock with |
2190 | * smp_call_function() if an IPI is sent by the same process we are |
2191 | * waiting to become inactive. |
2192 | */ |
2193 | unsigned long wait_task_inactive(struct task_struct *p, long match_state) |
2194 | { |
2195 | unsigned long flags; |
2196 | int running, on_rq; |
2197 | unsigned long ncsw; |
2198 | struct rq *rq; |
2199 | |
2200 | for (;;) { |
2201 | /* |
2202 | * We do the initial early heuristics without holding |
2203 | * any task-queue locks at all. We'll only try to get |
2204 | * the runqueue lock when things look like they will |
2205 | * work out! |
2206 | */ |
2207 | rq = task_rq(p); |
2208 | |
2209 | /* |
2210 | * If the task is actively running on another CPU |
2211 | * still, just relax and busy-wait without holding |
2212 | * any locks. |
2213 | * |
2214 | * NOTE! Since we don't hold any locks, it's not |
2215 | * even sure that "rq" stays as the right runqueue! |
2216 | * But we don't care, since "task_running()" will |
2217 | * return false if the runqueue has changed and p |
2218 | * is actually now running somewhere else! |
2219 | */ |
2220 | while (task_running(rq, p)) { |
2221 | if (match_state && unlikely(p->state != match_state)) |
2222 | return 0; |
2223 | cpu_relax(); |
2224 | } |
2225 | |
2226 | /* |
2227 | * Ok, time to look more closely! We need the rq |
2228 | * lock now, to be *sure*. If we're wrong, we'll |
2229 | * just go back and repeat. |
2230 | */ |
2231 | rq = task_rq_lock(p, &flags); |
2232 | trace_sched_wait_task(rq, p); |
2233 | running = task_running(rq, p); |
2234 | on_rq = p->se.on_rq; |
2235 | ncsw = 0; |
2236 | if (!match_state || p->state == match_state) |
2237 | ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ |
2238 | task_rq_unlock(rq, &flags); |
2239 | |
2240 | /* |
2241 | * If it changed from the expected state, bail out now. |
2242 | */ |
2243 | if (unlikely(!ncsw)) |
2244 | break; |
2245 | |
2246 | /* |
2247 | * Was it really running after all now that we |
2248 | * checked with the proper locks actually held? |
2249 | * |
2250 | * Oops. Go back and try again.. |
2251 | */ |
2252 | if (unlikely(running)) { |
2253 | cpu_relax(); |
2254 | continue; |
2255 | } |
2256 | |
2257 | /* |
2258 | * It's not enough that it's not actively running, |
2259 | * it must be off the runqueue _entirely_, and not |
2260 | * preempted! |
2261 | * |
2262 | * So if it was still runnable (but just not actively |
2263 | * running right now), it's preempted, and we should |
2264 | * yield - it could be a while. |
2265 | */ |
2266 | if (unlikely(on_rq)) { |
2267 | schedule_timeout_uninterruptible(1); |
2268 | continue; |
2269 | } |
2270 | |
2271 | /* |
2272 | * Ahh, all good. It wasn't running, and it wasn't |
2273 | * runnable, which means that it will never become |
2274 | * running in the future either. We're all done! |
2275 | */ |
2276 | break; |
2277 | } |
2278 | |
2279 | return ncsw; |
2280 | } |
2281 | |
2282 | /*** |
2283 | * kick_process - kick a running thread to enter/exit the kernel |
2284 | * @p: the to-be-kicked thread |
2285 | * |
2286 | * Cause a process which is running on another CPU to enter |
2287 | * kernel-mode, without any delay. (to get signals handled.) |
2288 | * |
2289 | * NOTE: this function doesnt have to take the runqueue lock, |
2290 | * because all it wants to ensure is that the remote task enters |
2291 | * the kernel. If the IPI races and the task has been migrated |
2292 | * to another CPU then no harm is done and the purpose has been |
2293 | * achieved as well. |
2294 | */ |
2295 | void kick_process(struct task_struct *p) |
2296 | { |
2297 | int cpu; |
2298 | |
2299 | preempt_disable(); |
2300 | cpu = task_cpu(p); |
2301 | if ((cpu != smp_processor_id()) && task_curr(p)) |
2302 | smp_send_reschedule(cpu); |
2303 | preempt_enable(); |
2304 | } |
2305 | EXPORT_SYMBOL_GPL(kick_process); |
2306 | #endif /* CONFIG_SMP */ |
2307 | |
2308 | /** |
2309 | * task_oncpu_function_call - call a function on the cpu on which a task runs |
2310 | * @p: the task to evaluate |
2311 | * @func: the function to be called |
2312 | * @info: the function call argument |
2313 | * |
2314 | * Calls the function @func when the task is currently running. This might |
2315 | * be on the current CPU, which just calls the function directly |
2316 | */ |
2317 | void task_oncpu_function_call(struct task_struct *p, |
2318 | void (*func) (void *info), void *info) |
2319 | { |
2320 | int cpu; |
2321 | |
2322 | preempt_disable(); |
2323 | cpu = task_cpu(p); |
2324 | if (task_curr(p)) |
2325 | smp_call_function_single(cpu, func, info, 1); |
2326 | preempt_enable(); |
2327 | } |
2328 | |
2329 | /*** |
2330 | * try_to_wake_up - wake up a thread |
2331 | * @p: the to-be-woken-up thread |
2332 | * @state: the mask of task states that can be woken |
2333 | * @sync: do a synchronous wakeup? |
2334 | * |
2335 | * Put it on the run-queue if it's not already there. The "current" |
2336 | * thread is always on the run-queue (except when the actual |
2337 | * re-schedule is in progress), and as such you're allowed to do |
2338 | * the simpler "current->state = TASK_RUNNING" to mark yourself |
2339 | * runnable without the overhead of this. |
2340 | * |
2341 | * returns failure only if the task is already active. |
2342 | */ |
2343 | static int try_to_wake_up(struct task_struct *p, unsigned int state, |
2344 | int wake_flags) |
2345 | { |
2346 | int cpu, orig_cpu, this_cpu, success = 0; |
2347 | unsigned long flags; |
2348 | struct rq *rq, *orig_rq; |
2349 | |
2350 | if (!sched_feat(SYNC_WAKEUPS)) |
2351 | wake_flags &= ~WF_SYNC; |
2352 | |
2353 | this_cpu = get_cpu(); |
2354 | |
2355 | smp_wmb(); |
2356 | rq = orig_rq = task_rq_lock(p, &flags); |
2357 | update_rq_clock(rq); |
2358 | if (!(p->state & state)) |
2359 | goto out; |
2360 | |
2361 | if (p->se.on_rq) |
2362 | goto out_running; |
2363 | |
2364 | cpu = task_cpu(p); |
2365 | orig_cpu = cpu; |
2366 | |
2367 | #ifdef CONFIG_SMP |
2368 | if (unlikely(task_running(rq, p))) |
2369 | goto out_activate; |
2370 | |
2371 | /* |
2372 | * In order to handle concurrent wakeups and release the rq->lock |
2373 | * we put the task in TASK_WAKING state. |
2374 | * |
2375 | * First fix up the nr_uninterruptible count: |
2376 | */ |
2377 | if (task_contributes_to_load(p)) |
2378 | rq->nr_uninterruptible--; |
2379 | p->state = TASK_WAKING; |
2380 | task_rq_unlock(rq, &flags); |
2381 | |
2382 | cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, wake_flags); |
2383 | if (cpu != orig_cpu) |
2384 | set_task_cpu(p, cpu); |
2385 | |
2386 | rq = task_rq_lock(p, &flags); |
2387 | |
2388 | if (rq != orig_rq) |
2389 | update_rq_clock(rq); |
2390 | |
2391 | WARN_ON(p->state != TASK_WAKING); |
2392 | cpu = task_cpu(p); |
2393 | |
2394 | #ifdef CONFIG_SCHEDSTATS |
2395 | schedstat_inc(rq, ttwu_count); |
2396 | if (cpu == this_cpu) |
2397 | schedstat_inc(rq, ttwu_local); |
2398 | else { |
2399 | struct sched_domain *sd; |
2400 | for_each_domain(this_cpu, sd) { |
2401 | if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
2402 | schedstat_inc(sd, ttwu_wake_remote); |
2403 | break; |
2404 | } |
2405 | } |
2406 | } |
2407 | #endif /* CONFIG_SCHEDSTATS */ |
2408 | |
2409 | out_activate: |
2410 | #endif /* CONFIG_SMP */ |
2411 | schedstat_inc(p, se.nr_wakeups); |
2412 | if (wake_flags & WF_SYNC) |
2413 | schedstat_inc(p, se.nr_wakeups_sync); |
2414 | if (orig_cpu != cpu) |
2415 | schedstat_inc(p, se.nr_wakeups_migrate); |
2416 | if (cpu == this_cpu) |
2417 | schedstat_inc(p, se.nr_wakeups_local); |
2418 | else |
2419 | schedstat_inc(p, se.nr_wakeups_remote); |
2420 | activate_task(rq, p, 1); |
2421 | success = 1; |
2422 | |
2423 | /* |
2424 | * Only attribute actual wakeups done by this task. |
2425 | */ |
2426 | if (!in_interrupt()) { |
2427 | struct sched_entity *se = ¤t->se; |
2428 | u64 sample = se->sum_exec_runtime; |
2429 | |
2430 | if (se->last_wakeup) |
2431 | sample -= se->last_wakeup; |
2432 | else |
2433 | sample -= se->start_runtime; |
2434 | update_avg(&se->avg_wakeup, sample); |
2435 | |
2436 | se->last_wakeup = se->sum_exec_runtime; |
2437 | } |
2438 | |
2439 | out_running: |
2440 | trace_sched_wakeup(rq, p, success); |
2441 | check_preempt_curr(rq, p, wake_flags); |
2442 | |
2443 | p->state = TASK_RUNNING; |
2444 | #ifdef CONFIG_SMP |
2445 | if (p->sched_class->task_wake_up) |
2446 | p->sched_class->task_wake_up(rq, p); |
2447 | |
2448 | if (unlikely(rq->idle_stamp)) { |
2449 | u64 delta = rq->clock - rq->idle_stamp; |
2450 | u64 max = 2*sysctl_sched_migration_cost; |
2451 | |
2452 | if (delta > max) |
2453 | rq->avg_idle = max; |
2454 | else |
2455 | update_avg(&rq->avg_idle, delta); |
2456 | rq->idle_stamp = 0; |
2457 | } |
2458 | #endif |
2459 | out: |
2460 | task_rq_unlock(rq, &flags); |
2461 | put_cpu(); |
2462 | |
2463 | return success; |
2464 | } |
2465 | |
2466 | /** |
2467 | * wake_up_process - Wake up a specific process |
2468 | * @p: The process to be woken up. |
2469 | * |
2470 | * Attempt to wake up the nominated process and move it to the set of runnable |
2471 | * processes. Returns 1 if the process was woken up, 0 if it was already |
2472 | * running. |
2473 | * |
2474 | * It may be assumed that this function implies a write memory barrier before |
2475 | * changing the task state if and only if any tasks are woken up. |
2476 | */ |
2477 | int wake_up_process(struct task_struct *p) |
2478 | { |
2479 | return try_to_wake_up(p, TASK_ALL, 0); |
2480 | } |
2481 | EXPORT_SYMBOL(wake_up_process); |
2482 | |
2483 | int wake_up_state(struct task_struct *p, unsigned int state) |
2484 | { |
2485 | return try_to_wake_up(p, state, 0); |
2486 | } |
2487 | |
2488 | /* |
2489 | * Perform scheduler related setup for a newly forked process p. |
2490 | * p is forked by current. |
2491 | * |
2492 | * __sched_fork() is basic setup used by init_idle() too: |
2493 | */ |
2494 | static void __sched_fork(struct task_struct *p) |
2495 | { |
2496 | p->se.exec_start = 0; |
2497 | p->se.sum_exec_runtime = 0; |
2498 | p->se.prev_sum_exec_runtime = 0; |
2499 | p->se.nr_migrations = 0; |
2500 | p->se.last_wakeup = 0; |
2501 | p->se.avg_overlap = 0; |
2502 | p->se.start_runtime = 0; |
2503 | p->se.avg_wakeup = sysctl_sched_wakeup_granularity; |
2504 | p->se.avg_running = 0; |
2505 | |
2506 | #ifdef CONFIG_SCHEDSTATS |
2507 | p->se.wait_start = 0; |
2508 | p->se.wait_max = 0; |
2509 | p->se.wait_count = 0; |
2510 | p->se.wait_sum = 0; |
2511 | |
2512 | p->se.sleep_start = 0; |
2513 | p->se.sleep_max = 0; |
2514 | p->se.sum_sleep_runtime = 0; |
2515 | |
2516 | p->se.block_start = 0; |
2517 | p->se.block_max = 0; |
2518 | p->se.exec_max = 0; |
2519 | p->se.slice_max = 0; |
2520 | |
2521 | p->se.nr_migrations_cold = 0; |
2522 | p->se.nr_failed_migrations_affine = 0; |
2523 | p->se.nr_failed_migrations_running = 0; |
2524 | p->se.nr_failed_migrations_hot = 0; |
2525 | p->se.nr_forced_migrations = 0; |
2526 | p->se.nr_forced2_migrations = 0; |
2527 | |
2528 | p->se.nr_wakeups = 0; |
2529 | p->se.nr_wakeups_sync = 0; |
2530 | p->se.nr_wakeups_migrate = 0; |
2531 | p->se.nr_wakeups_local = 0; |
2532 | p->se.nr_wakeups_remote = 0; |
2533 | p->se.nr_wakeups_affine = 0; |
2534 | p->se.nr_wakeups_affine_attempts = 0; |
2535 | p->se.nr_wakeups_passive = 0; |
2536 | p->se.nr_wakeups_idle = 0; |
2537 | |
2538 | #endif |
2539 | |
2540 | INIT_LIST_HEAD(&p->rt.run_list); |
2541 | p->se.on_rq = 0; |
2542 | INIT_LIST_HEAD(&p->se.group_node); |
2543 | |
2544 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
2545 | INIT_HLIST_HEAD(&p->preempt_notifiers); |
2546 | #endif |
2547 | |
2548 | /* |
2549 | * We mark the process as running here, but have not actually |
2550 | * inserted it onto the runqueue yet. This guarantees that |
2551 | * nobody will actually run it, and a signal or other external |
2552 | * event cannot wake it up and insert it on the runqueue either. |
2553 | */ |
2554 | p->state = TASK_RUNNING; |
2555 | } |
2556 | |
2557 | /* |
2558 | * fork()/clone()-time setup: |
2559 | */ |
2560 | void sched_fork(struct task_struct *p, int clone_flags) |
2561 | { |
2562 | int cpu = get_cpu(); |
2563 | |
2564 | __sched_fork(p); |
2565 | |
2566 | /* |
2567 | * Revert to default priority/policy on fork if requested. |
2568 | */ |
2569 | if (unlikely(p->sched_reset_on_fork)) { |
2570 | if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) { |
2571 | p->policy = SCHED_NORMAL; |
2572 | p->normal_prio = p->static_prio; |
2573 | } |
2574 | |
2575 | if (PRIO_TO_NICE(p->static_prio) < 0) { |
2576 | p->static_prio = NICE_TO_PRIO(0); |
2577 | p->normal_prio = p->static_prio; |
2578 | set_load_weight(p); |
2579 | } |
2580 | |
2581 | /* |
2582 | * We don't need the reset flag anymore after the fork. It has |
2583 | * fulfilled its duty: |
2584 | */ |
2585 | p->sched_reset_on_fork = 0; |
2586 | } |
2587 | |
2588 | /* |
2589 | * Make sure we do not leak PI boosting priority to the child. |
2590 | */ |
2591 | p->prio = current->normal_prio; |
2592 | |
2593 | if (!rt_prio(p->prio)) |
2594 | p->sched_class = &fair_sched_class; |
2595 | |
2596 | #ifdef CONFIG_SMP |
2597 | cpu = p->sched_class->select_task_rq(p, SD_BALANCE_FORK, 0); |
2598 | #endif |
2599 | set_task_cpu(p, cpu); |
2600 | |
2601 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
2602 | if (likely(sched_info_on())) |
2603 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
2604 | #endif |
2605 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
2606 | p->oncpu = 0; |
2607 | #endif |
2608 | #ifdef CONFIG_PREEMPT |
2609 | /* Want to start with kernel preemption disabled. */ |
2610 | task_thread_info(p)->preempt_count = 1; |
2611 | #endif |
2612 | plist_node_init(&p->pushable_tasks, MAX_PRIO); |
2613 | |
2614 | put_cpu(); |
2615 | } |
2616 | |
2617 | /* |
2618 | * wake_up_new_task - wake up a newly created task for the first time. |
2619 | * |
2620 | * This function will do some initial scheduler statistics housekeeping |
2621 | * that must be done for every newly created context, then puts the task |
2622 | * on the runqueue and wakes it. |
2623 | */ |
2624 | void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
2625 | { |
2626 | unsigned long flags; |
2627 | struct rq *rq; |
2628 | |
2629 | rq = task_rq_lock(p, &flags); |
2630 | BUG_ON(p->state != TASK_RUNNING); |
2631 | update_rq_clock(rq); |
2632 | |
2633 | if (!p->sched_class->task_new || !current->se.on_rq) { |
2634 | activate_task(rq, p, 0); |
2635 | } else { |
2636 | /* |
2637 | * Let the scheduling class do new task startup |
2638 | * management (if any): |
2639 | */ |
2640 | p->sched_class->task_new(rq, p); |
2641 | inc_nr_running(rq); |
2642 | } |
2643 | trace_sched_wakeup_new(rq, p, 1); |
2644 | check_preempt_curr(rq, p, WF_FORK); |
2645 | #ifdef CONFIG_SMP |
2646 | if (p->sched_class->task_wake_up) |
2647 | p->sched_class->task_wake_up(rq, p); |
2648 | #endif |
2649 | task_rq_unlock(rq, &flags); |
2650 | } |
2651 | |
2652 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
2653 | |
2654 | /** |
2655 | * preempt_notifier_register - tell me when current is being preempted & rescheduled |
2656 | * @notifier: notifier struct to register |
2657 | */ |
2658 | void preempt_notifier_register(struct preempt_notifier *notifier) |
2659 | { |
2660 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); |
2661 | } |
2662 | EXPORT_SYMBOL_GPL(preempt_notifier_register); |
2663 | |
2664 | /** |
2665 | * preempt_notifier_unregister - no longer interested in preemption notifications |
2666 | * @notifier: notifier struct to unregister |
2667 | * |
2668 | * This is safe to call from within a preemption notifier. |
2669 | */ |
2670 | void preempt_notifier_unregister(struct preempt_notifier *notifier) |
2671 | { |
2672 | hlist_del(¬ifier->link); |
2673 | } |
2674 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); |
2675 | |
2676 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
2677 | { |
2678 | struct preempt_notifier *notifier; |
2679 | struct hlist_node *node; |
2680 | |
2681 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) |
2682 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); |
2683 | } |
2684 | |
2685 | static void |
2686 | fire_sched_out_preempt_notifiers(struct task_struct *curr, |
2687 | struct task_struct *next) |
2688 | { |
2689 | struct preempt_notifier *notifier; |
2690 | struct hlist_node *node; |
2691 | |
2692 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) |
2693 | notifier->ops->sched_out(notifier, next); |
2694 | } |
2695 | |
2696 | #else /* !CONFIG_PREEMPT_NOTIFIERS */ |
2697 | |
2698 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
2699 | { |
2700 | } |
2701 | |
2702 | static void |
2703 | fire_sched_out_preempt_notifiers(struct task_struct *curr, |
2704 | struct task_struct *next) |
2705 | { |
2706 | } |
2707 | |
2708 | #endif /* CONFIG_PREEMPT_NOTIFIERS */ |
2709 | |
2710 | /** |
2711 | * prepare_task_switch - prepare to switch tasks |
2712 | * @rq: the runqueue preparing to switch |
2713 | * @prev: the current task that is being switched out |
2714 | * @next: the task we are going to switch to. |
2715 | * |
2716 | * This is called with the rq lock held and interrupts off. It must |
2717 | * be paired with a subsequent finish_task_switch after the context |
2718 | * switch. |
2719 | * |
2720 | * prepare_task_switch sets up locking and calls architecture specific |
2721 | * hooks. |
2722 | */ |
2723 | static inline void |
2724 | prepare_task_switch(struct rq *rq, struct task_struct *prev, |
2725 | struct task_struct *next) |
2726 | { |
2727 | fire_sched_out_preempt_notifiers(prev, next); |
2728 | prepare_lock_switch(rq, next); |
2729 | prepare_arch_switch(next); |
2730 | } |
2731 | |
2732 | /** |
2733 | * finish_task_switch - clean up after a task-switch |
2734 | * @rq: runqueue associated with task-switch |
2735 | * @prev: the thread we just switched away from. |
2736 | * |
2737 | * finish_task_switch must be called after the context switch, paired |
2738 | * with a prepare_task_switch call before the context switch. |
2739 | * finish_task_switch will reconcile locking set up by prepare_task_switch, |
2740 | * and do any other architecture-specific cleanup actions. |
2741 | * |
2742 | * Note that we may have delayed dropping an mm in context_switch(). If |
2743 | * so, we finish that here outside of the runqueue lock. (Doing it |
2744 | * with the lock held can cause deadlocks; see schedule() for |
2745 | * details.) |
2746 | */ |
2747 | static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
2748 | __releases(rq->lock) |
2749 | { |
2750 | struct mm_struct *mm = rq->prev_mm; |
2751 | long prev_state; |
2752 | |
2753 | rq->prev_mm = NULL; |
2754 | |
2755 | /* |
2756 | * A task struct has one reference for the use as "current". |
2757 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
2758 | * schedule one last time. The schedule call will never return, and |
2759 | * the scheduled task must drop that reference. |
2760 | * The test for TASK_DEAD must occur while the runqueue locks are |
2761 | * still held, otherwise prev could be scheduled on another cpu, die |
2762 | * there before we look at prev->state, and then the reference would |
2763 | * be dropped twice. |
2764 | * Manfred Spraul <manfred@colorfullife.com> |
2765 | */ |
2766 | prev_state = prev->state; |
2767 | finish_arch_switch(prev); |
2768 | perf_event_task_sched_in(current, cpu_of(rq)); |
2769 | finish_lock_switch(rq, prev); |
2770 | |
2771 | fire_sched_in_preempt_notifiers(current); |
2772 | if (mm) |
2773 | mmdrop(mm); |
2774 | if (unlikely(prev_state == TASK_DEAD)) { |
2775 | /* |
2776 | * Remove function-return probe instances associated with this |
2777 | * task and put them back on the free list. |
2778 | */ |
2779 | kprobe_flush_task(prev); |
2780 | put_task_struct(prev); |
2781 | } |
2782 | } |
2783 | |
2784 | #ifdef CONFIG_SMP |
2785 | |
2786 | /* assumes rq->lock is held */ |
2787 | static inline void pre_schedule(struct rq *rq, struct task_struct *prev) |
2788 | { |
2789 | if (prev->sched_class->pre_schedule) |
2790 | prev->sched_class->pre_schedule(rq, prev); |
2791 | } |
2792 | |
2793 | /* rq->lock is NOT held, but preemption is disabled */ |
2794 | static inline void post_schedule(struct rq *rq) |
2795 | { |
2796 | if (rq->post_schedule) { |
2797 | unsigned long flags; |
2798 | |
2799 | spin_lock_irqsave(&rq->lock, flags); |
2800 | if (rq->curr->sched_class->post_schedule) |
2801 | rq->curr->sched_class->post_schedule(rq); |
2802 | spin_unlock_irqrestore(&rq->lock, flags); |
2803 | |
2804 | rq->post_schedule = 0; |
2805 | } |
2806 | } |
2807 | |
2808 | #else |
2809 | |
2810 | static inline void pre_schedule(struct rq *rq, struct task_struct *p) |
2811 | { |
2812 | } |
2813 | |
2814 | static inline void post_schedule(struct rq *rq) |
2815 | { |
2816 | } |
2817 | |
2818 | #endif |
2819 | |
2820 | /** |
2821 | * schedule_tail - first thing a freshly forked thread must call. |
2822 | * @prev: the thread we just switched away from. |
2823 | */ |
2824 | asmlinkage void schedule_tail(struct task_struct *prev) |
2825 | __releases(rq->lock) |
2826 | { |
2827 | struct rq *rq = this_rq(); |
2828 | |
2829 | finish_task_switch(rq, prev); |
2830 | |
2831 | /* |
2832 | * FIXME: do we need to worry about rq being invalidated by the |
2833 | * task_switch? |
2834 | */ |
2835 | post_schedule(rq); |
2836 | |
2837 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW |
2838 | /* In this case, finish_task_switch does not reenable preemption */ |
2839 | preempt_enable(); |
2840 | #endif |
2841 | if (current->set_child_tid) |
2842 | put_user(task_pid_vnr(current), current->set_child_tid); |
2843 | } |
2844 | |
2845 | /* |
2846 | * context_switch - switch to the new MM and the new |
2847 | * thread's register state. |
2848 | */ |
2849 | static inline void |
2850 | context_switch(struct rq *rq, struct task_struct *prev, |
2851 | struct task_struct *next) |
2852 | { |
2853 | struct mm_struct *mm, *oldmm; |
2854 | |
2855 | prepare_task_switch(rq, prev, next); |
2856 | trace_sched_switch(rq, prev, next); |
2857 | mm = next->mm; |
2858 | oldmm = prev->active_mm; |
2859 | /* |
2860 | * For paravirt, this is coupled with an exit in switch_to to |
2861 | * combine the page table reload and the switch backend into |
2862 | * one hypercall. |
2863 | */ |
2864 | arch_start_context_switch(prev); |
2865 | |
2866 | if (unlikely(!mm)) { |
2867 | next->active_mm = oldmm; |
2868 | atomic_inc(&oldmm->mm_count); |
2869 | enter_lazy_tlb(oldmm, next); |
2870 | } else |
2871 | switch_mm(oldmm, mm, next); |
2872 | |
2873 | if (unlikely(!prev->mm)) { |
2874 | prev->active_mm = NULL; |
2875 | rq->prev_mm = oldmm; |
2876 | } |
2877 | /* |
2878 | * Since the runqueue lock will be released by the next |
2879 | * task (which is an invalid locking op but in the case |
2880 | * of the scheduler it's an obvious special-case), so we |
2881 | * do an early lockdep release here: |
2882 | */ |
2883 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
2884 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
2885 | #endif |
2886 | |
2887 | /* Here we just switch the register state and the stack. */ |
2888 | switch_to(prev, next, prev); |
2889 | |
2890 | barrier(); |
2891 | /* |
2892 | * this_rq must be evaluated again because prev may have moved |
2893 | * CPUs since it called schedule(), thus the 'rq' on its stack |
2894 | * frame will be invalid. |
2895 | */ |
2896 | finish_task_switch(this_rq(), prev); |
2897 | } |
2898 | |
2899 | /* |
2900 | * nr_running, nr_uninterruptible and nr_context_switches: |
2901 | * |
2902 | * externally visible scheduler statistics: current number of runnable |
2903 | * threads, current number of uninterruptible-sleeping threads, total |
2904 | * number of context switches performed since bootup. |
2905 | */ |
2906 | unsigned long nr_running(void) |
2907 | { |
2908 | unsigned long i, sum = 0; |
2909 | |
2910 | for_each_online_cpu(i) |
2911 | sum += cpu_rq(i)->nr_running; |
2912 | |
2913 | return sum; |
2914 | } |
2915 | |
2916 | unsigned long nr_uninterruptible(void) |
2917 | { |
2918 | unsigned long i, sum = 0; |
2919 | |
2920 | for_each_possible_cpu(i) |
2921 | sum += cpu_rq(i)->nr_uninterruptible; |
2922 | |
2923 | /* |
2924 | * Since we read the counters lockless, it might be slightly |
2925 | * inaccurate. Do not allow it to go below zero though: |
2926 | */ |
2927 | if (unlikely((long)sum < 0)) |
2928 | sum = 0; |
2929 | |
2930 | return sum; |
2931 | } |
2932 | |
2933 | unsigned long long nr_context_switches(void) |
2934 | { |
2935 | int i; |
2936 | unsigned long long sum = 0; |
2937 | |
2938 | for_each_possible_cpu(i) |
2939 | sum += cpu_rq(i)->nr_switches; |
2940 | |
2941 | return sum; |
2942 | } |
2943 | |
2944 | unsigned long nr_iowait(void) |
2945 | { |
2946 | unsigned long i, sum = 0; |
2947 | |
2948 | for_each_possible_cpu(i) |
2949 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
2950 | |
2951 | return sum; |
2952 | } |
2953 | |
2954 | unsigned long nr_iowait_cpu(void) |
2955 | { |
2956 | struct rq *this = this_rq(); |
2957 | return atomic_read(&this->nr_iowait); |
2958 | } |
2959 | |
2960 | unsigned long this_cpu_load(void) |
2961 | { |
2962 | struct rq *this = this_rq(); |
2963 | return this->cpu_load[0]; |
2964 | } |
2965 | |
2966 | |
2967 | /* Variables and functions for calc_load */ |
2968 | static atomic_long_t calc_load_tasks; |
2969 | static unsigned long calc_load_update; |
2970 | unsigned long avenrun[3]; |
2971 | EXPORT_SYMBOL(avenrun); |
2972 | |
2973 | /** |
2974 | * get_avenrun - get the load average array |
2975 | * @loads: pointer to dest load array |
2976 | * @offset: offset to add |
2977 | * @shift: shift count to shift the result left |
2978 | * |
2979 | * These values are estimates at best, so no need for locking. |
2980 | */ |
2981 | void get_avenrun(unsigned long *loads, unsigned long offset, int shift) |
2982 | { |
2983 | loads[0] = (avenrun[0] + offset) << shift; |
2984 | loads[1] = (avenrun[1] + offset) << shift; |
2985 | loads[2] = (avenrun[2] + offset) << shift; |
2986 | } |
2987 | |
2988 | static unsigned long |
2989 | calc_load(unsigned long load, unsigned long exp, unsigned long active) |
2990 | { |
2991 | load *= exp; |
2992 | load += active * (FIXED_1 - exp); |
2993 | return load >> FSHIFT; |
2994 | } |
2995 | |
2996 | /* |
2997 | * calc_load - update the avenrun load estimates 10 ticks after the |
2998 | * CPUs have updated calc_load_tasks. |
2999 | */ |
3000 | void calc_global_load(void) |
3001 | { |
3002 | unsigned long upd = calc_load_update + 10; |
3003 | long active; |
3004 | |
3005 | if (time_before(jiffies, upd)) |
3006 | return; |
3007 | |
3008 | active = atomic_long_read(&calc_load_tasks); |
3009 | active = active > 0 ? active * FIXED_1 : 0; |
3010 | |
3011 | avenrun[0] = calc_load(avenrun[0], EXP_1, active); |
3012 | avenrun[1] = calc_load(avenrun[1], EXP_5, active); |
3013 | avenrun[2] = calc_load(avenrun[2], EXP_15, active); |
3014 | |
3015 | calc_load_update += LOAD_FREQ; |
3016 | } |
3017 | |
3018 | /* |
3019 | * Either called from update_cpu_load() or from a cpu going idle |
3020 | */ |
3021 | static void calc_load_account_active(struct rq *this_rq) |
3022 | { |
3023 | long nr_active, delta; |
3024 | |
3025 | nr_active = this_rq->nr_running; |
3026 | nr_active += (long) this_rq->nr_uninterruptible; |
3027 | |
3028 | if (nr_active != this_rq->calc_load_active) { |
3029 | delta = nr_active - this_rq->calc_load_active; |
3030 | this_rq->calc_load_active = nr_active; |
3031 | atomic_long_add(delta, &calc_load_tasks); |
3032 | } |
3033 | } |
3034 | |
3035 | /* |
3036 | * Externally visible per-cpu scheduler statistics: |
3037 | * cpu_nr_migrations(cpu) - number of migrations into that cpu |
3038 | */ |
3039 | u64 cpu_nr_migrations(int cpu) |
3040 | { |
3041 | return cpu_rq(cpu)->nr_migrations_in; |
3042 | } |
3043 | |
3044 | /* |
3045 | * Update rq->cpu_load[] statistics. This function is usually called every |
3046 | * scheduler tick (TICK_NSEC). |
3047 | */ |
3048 | static void update_cpu_load(struct rq *this_rq) |
3049 | { |
3050 | unsigned long this_load = this_rq->load.weight; |
3051 | int i, scale; |
3052 | |
3053 | this_rq->nr_load_updates++; |
3054 | |
3055 | /* Update our load: */ |
3056 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { |
3057 | unsigned long old_load, new_load; |
3058 | |
3059 | /* scale is effectively 1 << i now, and >> i divides by scale */ |
3060 | |
3061 | old_load = this_rq->cpu_load[i]; |
3062 | new_load = this_load; |
3063 | /* |
3064 | * Round up the averaging division if load is increasing. This |
3065 | * prevents us from getting stuck on 9 if the load is 10, for |
3066 | * example. |
3067 | */ |
3068 | if (new_load > old_load) |
3069 | new_load += scale-1; |
3070 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; |
3071 | } |
3072 | |
3073 | if (time_after_eq(jiffies, this_rq->calc_load_update)) { |
3074 | this_rq->calc_load_update += LOAD_FREQ; |
3075 | calc_load_account_active(this_rq); |
3076 | } |
3077 | } |
3078 | |
3079 | #ifdef CONFIG_SMP |
3080 | |
3081 | /* |
3082 | * double_rq_lock - safely lock two runqueues |
3083 | * |
3084 | * Note this does not disable interrupts like task_rq_lock, |
3085 | * you need to do so manually before calling. |
3086 | */ |
3087 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
3088 | __acquires(rq1->lock) |
3089 | __acquires(rq2->lock) |
3090 | { |
3091 | BUG_ON(!irqs_disabled()); |
3092 | if (rq1 == rq2) { |
3093 | spin_lock(&rq1->lock); |
3094 | __acquire(rq2->lock); /* Fake it out ;) */ |
3095 | } else { |
3096 | if (rq1 < rq2) { |
3097 | spin_lock(&rq1->lock); |
3098 | spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING); |
3099 | } else { |
3100 | spin_lock(&rq2->lock); |
3101 | spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING); |
3102 | } |
3103 | } |
3104 | update_rq_clock(rq1); |
3105 | update_rq_clock(rq2); |
3106 | } |
3107 | |
3108 | /* |
3109 | * double_rq_unlock - safely unlock two runqueues |
3110 | * |
3111 | * Note this does not restore interrupts like task_rq_unlock, |
3112 | * you need to do so manually after calling. |
3113 | */ |
3114 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
3115 | __releases(rq1->lock) |
3116 | __releases(rq2->lock) |
3117 | { |
3118 | spin_unlock(&rq1->lock); |
3119 | if (rq1 != rq2) |
3120 | spin_unlock(&rq2->lock); |
3121 | else |
3122 | __release(rq2->lock); |
3123 | } |
3124 | |
3125 | /* |
3126 | * If dest_cpu is allowed for this process, migrate the task to it. |
3127 | * This is accomplished by forcing the cpu_allowed mask to only |
3128 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then |
3129 | * the cpu_allowed mask is restored. |
3130 | */ |
3131 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
3132 | { |
3133 | struct migration_req req; |
3134 | unsigned long flags; |
3135 | struct rq *rq; |
3136 | |
3137 | rq = task_rq_lock(p, &flags); |
3138 | if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed) |
3139 | || unlikely(!cpu_active(dest_cpu))) |
3140 | goto out; |
3141 | |
3142 | /* force the process onto the specified CPU */ |
3143 | if (migrate_task(p, dest_cpu, &req)) { |
3144 | /* Need to wait for migration thread (might exit: take ref). */ |
3145 | struct task_struct *mt = rq->migration_thread; |
3146 | |
3147 | get_task_struct(mt); |
3148 | task_rq_unlock(rq, &flags); |
3149 | wake_up_process(mt); |
3150 | put_task_struct(mt); |
3151 | wait_for_completion(&req.done); |
3152 | |
3153 | return; |
3154 | } |
3155 | out: |
3156 | task_rq_unlock(rq, &flags); |
3157 | } |
3158 | |
3159 | /* |
3160 | * sched_exec - execve() is a valuable balancing opportunity, because at |
3161 | * this point the task has the smallest effective memory and cache footprint. |
3162 | */ |
3163 | void sched_exec(void) |
3164 | { |
3165 | int new_cpu, this_cpu = get_cpu(); |
3166 | new_cpu = current->sched_class->select_task_rq(current, SD_BALANCE_EXEC, 0); |
3167 | put_cpu(); |
3168 | if (new_cpu != this_cpu) |
3169 | sched_migrate_task(current, new_cpu); |
3170 | } |
3171 | |
3172 | /* |
3173 | * pull_task - move a task from a remote runqueue to the local runqueue. |
3174 | * Both runqueues must be locked. |
3175 | */ |
3176 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
3177 | struct rq *this_rq, int this_cpu) |
3178 | { |
3179 | deactivate_task(src_rq, p, 0); |
3180 | set_task_cpu(p, this_cpu); |
3181 | activate_task(this_rq, p, 0); |
3182 | check_preempt_curr(this_rq, p, 0); |
3183 | } |
3184 | |
3185 | /* |
3186 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? |
3187 | */ |
3188 | static |
3189 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
3190 | struct sched_domain *sd, enum cpu_idle_type idle, |
3191 | int *all_pinned) |
3192 | { |
3193 | int tsk_cache_hot = 0; |
3194 | /* |
3195 | * We do not migrate tasks that are: |
3196 | * 1) running (obviously), or |
3197 | * 2) cannot be migrated to this CPU due to cpus_allowed, or |
3198 | * 3) are cache-hot on their current CPU. |
3199 | */ |
3200 | if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) { |
3201 | schedstat_inc(p, se.nr_failed_migrations_affine); |
3202 | return 0; |
3203 | } |
3204 | *all_pinned = 0; |
3205 | |
3206 | if (task_running(rq, p)) { |
3207 | schedstat_inc(p, se.nr_failed_migrations_running); |
3208 | return 0; |
3209 | } |
3210 | |
3211 | /* |
3212 | * Aggressive migration if: |
3213 | * 1) task is cache cold, or |
3214 | * 2) too many balance attempts have failed. |
3215 | */ |
3216 | |
3217 | tsk_cache_hot = task_hot(p, rq->clock, sd); |
3218 | if (!tsk_cache_hot || |
3219 | sd->nr_balance_failed > sd->cache_nice_tries) { |
3220 | #ifdef CONFIG_SCHEDSTATS |
3221 | if (tsk_cache_hot) { |
3222 | schedstat_inc(sd, lb_hot_gained[idle]); |
3223 | schedstat_inc(p, se.nr_forced_migrations); |
3224 | } |
3225 | #endif |
3226 | return 1; |
3227 | } |
3228 | |
3229 | if (tsk_cache_hot) { |
3230 | schedstat_inc(p, se.nr_failed_migrations_hot); |
3231 | return 0; |
3232 | } |
3233 | return 1; |
3234 | } |
3235 | |
3236 | static unsigned long |
3237 | balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
3238 | unsigned long max_load_move, struct sched_domain *sd, |
3239 | enum cpu_idle_type idle, int *all_pinned, |
3240 | int *this_best_prio, struct rq_iterator *iterator) |
3241 | { |
3242 | int loops = 0, pulled = 0, pinned = 0; |
3243 | struct task_struct *p; |
3244 | long rem_load_move = max_load_move; |
3245 | |
3246 | if (max_load_move == 0) |
3247 | goto out; |
3248 | |
3249 | pinned = 1; |
3250 | |
3251 | /* |
3252 | * Start the load-balancing iterator: |
3253 | */ |
3254 | p = iterator->start(iterator->arg); |
3255 | next: |
3256 | if (!p || loops++ > sysctl_sched_nr_migrate) |
3257 | goto out; |
3258 | |
3259 | if ((p->se.load.weight >> 1) > rem_load_move || |
3260 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
3261 | p = iterator->next(iterator->arg); |
3262 | goto next; |
3263 | } |
3264 | |
3265 | pull_task(busiest, p, this_rq, this_cpu); |
3266 | pulled++; |
3267 | rem_load_move -= p->se.load.weight; |
3268 | |
3269 | #ifdef CONFIG_PREEMPT |
3270 | /* |
3271 | * NEWIDLE balancing is a source of latency, so preemptible kernels |
3272 | * will stop after the first task is pulled to minimize the critical |
3273 | * section. |
3274 | */ |
3275 | if (idle == CPU_NEWLY_IDLE) |
3276 | goto out; |
3277 | #endif |
3278 | |
3279 | /* |
3280 | * We only want to steal up to the prescribed amount of weighted load. |
3281 | */ |
3282 | if (rem_load_move > 0) { |
3283 | if (p->prio < *this_best_prio) |
3284 | *this_best_prio = p->prio; |
3285 | p = iterator->next(iterator->arg); |
3286 | goto next; |
3287 | } |
3288 | out: |
3289 | /* |
3290 | * Right now, this is one of only two places pull_task() is called, |
3291 | * so we can safely collect pull_task() stats here rather than |
3292 | * inside pull_task(). |
3293 | */ |
3294 | schedstat_add(sd, lb_gained[idle], pulled); |
3295 | |
3296 | if (all_pinned) |
3297 | *all_pinned = pinned; |
3298 | |
3299 | return max_load_move - rem_load_move; |
3300 | } |
3301 | |
3302 | /* |
3303 | * move_tasks tries to move up to max_load_move weighted load from busiest to |
3304 | * this_rq, as part of a balancing operation within domain "sd". |
3305 | * Returns 1 if successful and 0 otherwise. |
3306 | * |
3307 | * Called with both runqueues locked. |
3308 | */ |
3309 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
3310 | unsigned long max_load_move, |
3311 | struct sched_domain *sd, enum cpu_idle_type idle, |
3312 | int *all_pinned) |
3313 | { |
3314 | const struct sched_class *class = sched_class_highest; |
3315 | unsigned long total_load_moved = 0; |
3316 | int this_best_prio = this_rq->curr->prio; |
3317 | |
3318 | do { |
3319 | total_load_moved += |
3320 | class->load_balance(this_rq, this_cpu, busiest, |
3321 | max_load_move - total_load_moved, |
3322 | sd, idle, all_pinned, &this_best_prio); |
3323 | class = class->next; |
3324 | |
3325 | #ifdef CONFIG_PREEMPT |
3326 | /* |
3327 | * NEWIDLE balancing is a source of latency, so preemptible |
3328 | * kernels will stop after the first task is pulled to minimize |
3329 | * the critical section. |
3330 | */ |
3331 | if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) |
3332 | break; |
3333 | #endif |
3334 | } while (class && max_load_move > total_load_moved); |
3335 | |
3336 | return total_load_moved > 0; |
3337 | } |
3338 | |
3339 | static int |
3340 | iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, |
3341 | struct sched_domain *sd, enum cpu_idle_type idle, |
3342 | struct rq_iterator *iterator) |
3343 | { |
3344 | struct task_struct *p = iterator->start(iterator->arg); |
3345 | int pinned = 0; |
3346 | |
3347 | while (p) { |
3348 | if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
3349 | pull_task(busiest, p, this_rq, this_cpu); |
3350 | /* |
3351 | * Right now, this is only the second place pull_task() |
3352 | * is called, so we can safely collect pull_task() |
3353 | * stats here rather than inside pull_task(). |
3354 | */ |
3355 | schedstat_inc(sd, lb_gained[idle]); |
3356 | |
3357 | return 1; |
3358 | } |
3359 | p = iterator->next(iterator->arg); |
3360 | } |
3361 | |
3362 | return 0; |
3363 | } |
3364 | |
3365 | /* |
3366 | * move_one_task tries to move exactly one task from busiest to this_rq, as |
3367 | * part of active balancing operations within "domain". |
3368 | * Returns 1 if successful and 0 otherwise. |
3369 | * |
3370 | * Called with both runqueues locked. |
3371 | */ |
3372 | static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, |
3373 | struct sched_domain *sd, enum cpu_idle_type idle) |
3374 | { |
3375 | const struct sched_class *class; |
3376 | |
3377 | for_each_class(class) { |
3378 | if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) |
3379 | return 1; |
3380 | } |
3381 | |
3382 | return 0; |
3383 | } |
3384 | /********** Helpers for find_busiest_group ************************/ |
3385 | /* |
3386 | * sd_lb_stats - Structure to store the statistics of a sched_domain |
3387 | * during load balancing. |
3388 | */ |
3389 | struct sd_lb_stats { |
3390 | struct sched_group *busiest; /* Busiest group in this sd */ |
3391 | struct sched_group *this; /* Local group in this sd */ |
3392 | unsigned long total_load; /* Total load of all groups in sd */ |
3393 | unsigned long total_pwr; /* Total power of all groups in sd */ |
3394 | unsigned long avg_load; /* Average load across all groups in sd */ |
3395 | |
3396 | /** Statistics of this group */ |
3397 | unsigned long this_load; |
3398 | unsigned long this_load_per_task; |
3399 | unsigned long this_nr_running; |
3400 | |
3401 | /* Statistics of the busiest group */ |
3402 | unsigned long max_load; |
3403 | unsigned long busiest_load_per_task; |
3404 | unsigned long busiest_nr_running; |
3405 | |
3406 | int group_imb; /* Is there imbalance in this sd */ |
3407 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
3408 | int power_savings_balance; /* Is powersave balance needed for this sd */ |
3409 | struct sched_group *group_min; /* Least loaded group in sd */ |
3410 | struct sched_group *group_leader; /* Group which relieves group_min */ |
3411 | unsigned long min_load_per_task; /* load_per_task in group_min */ |
3412 | unsigned long leader_nr_running; /* Nr running of group_leader */ |
3413 | unsigned long min_nr_running; /* Nr running of group_min */ |
3414 | #endif |
3415 | }; |
3416 | |
3417 | /* |
3418 | * sg_lb_stats - stats of a sched_group required for load_balancing |
3419 | */ |
3420 | struct sg_lb_stats { |
3421 | unsigned long avg_load; /*Avg load across the CPUs of the group */ |
3422 | unsigned long group_load; /* Total load over the CPUs of the group */ |
3423 | unsigned long sum_nr_running; /* Nr tasks running in the group */ |
3424 | unsigned long sum_weighted_load; /* Weighted load of group's tasks */ |
3425 | unsigned long group_capacity; |
3426 | int group_imb; /* Is there an imbalance in the group ? */ |
3427 | }; |
3428 | |
3429 | /** |
3430 | * group_first_cpu - Returns the first cpu in the cpumask of a sched_group. |
3431 | * @group: The group whose first cpu is to be returned. |
3432 | */ |
3433 | static inline unsigned int group_first_cpu(struct sched_group *group) |
3434 | { |
3435 | return cpumask_first(sched_group_cpus(group)); |
3436 | } |
3437 | |
3438 | /** |
3439 | * get_sd_load_idx - Obtain the load index for a given sched domain. |
3440 | * @sd: The sched_domain whose load_idx is to be obtained. |
3441 | * @idle: The Idle status of the CPU for whose sd load_icx is obtained. |
3442 | */ |
3443 | static inline int get_sd_load_idx(struct sched_domain *sd, |
3444 | enum cpu_idle_type idle) |
3445 | { |
3446 | int load_idx; |
3447 | |
3448 | switch (idle) { |
3449 | case CPU_NOT_IDLE: |
3450 | load_idx = sd->busy_idx; |
3451 | break; |
3452 | |
3453 | case CPU_NEWLY_IDLE: |
3454 | load_idx = sd->newidle_idx; |
3455 | break; |
3456 | default: |
3457 | load_idx = sd->idle_idx; |
3458 | break; |
3459 | } |
3460 | |
3461 | return load_idx; |
3462 | } |
3463 | |
3464 | |
3465 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
3466 | /** |
3467 | * init_sd_power_savings_stats - Initialize power savings statistics for |
3468 | * the given sched_domain, during load balancing. |
3469 | * |
3470 | * @sd: Sched domain whose power-savings statistics are to be initialized. |
3471 | * @sds: Variable containing the statistics for sd. |
3472 | * @idle: Idle status of the CPU at which we're performing load-balancing. |
3473 | */ |
3474 | static inline void init_sd_power_savings_stats(struct sched_domain *sd, |
3475 | struct sd_lb_stats *sds, enum cpu_idle_type idle) |
3476 | { |
3477 | /* |
3478 | * Busy processors will not participate in power savings |
3479 | * balance. |
3480 | */ |
3481 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
3482 | sds->power_savings_balance = 0; |
3483 | else { |
3484 | sds->power_savings_balance = 1; |
3485 | sds->min_nr_running = ULONG_MAX; |
3486 | sds->leader_nr_running = 0; |
3487 | } |
3488 | } |
3489 | |
3490 | /** |
3491 | * update_sd_power_savings_stats - Update the power saving stats for a |
3492 | * sched_domain while performing load balancing. |
3493 | * |
3494 | * @group: sched_group belonging to the sched_domain under consideration. |
3495 | * @sds: Variable containing the statistics of the sched_domain |
3496 | * @local_group: Does group contain the CPU for which we're performing |
3497 | * load balancing ? |
3498 | * @sgs: Variable containing the statistics of the group. |
3499 | */ |
3500 | static inline void update_sd_power_savings_stats(struct sched_group *group, |
3501 | struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) |
3502 | { |
3503 | |
3504 | if (!sds->power_savings_balance) |
3505 | return; |
3506 | |
3507 | /* |
3508 | * If the local group is idle or completely loaded |
3509 | * no need to do power savings balance at this domain |
3510 | */ |
3511 | if (local_group && (sds->this_nr_running >= sgs->group_capacity || |
3512 | !sds->this_nr_running)) |
3513 | sds->power_savings_balance = 0; |
3514 | |
3515 | /* |
3516 | * If a group is already running at full capacity or idle, |
3517 | * don't include that group in power savings calculations |
3518 | */ |
3519 | if (!sds->power_savings_balance || |
3520 | sgs->sum_nr_running >= sgs->group_capacity || |
3521 | !sgs->sum_nr_running) |
3522 | return; |
3523 | |
3524 | /* |
3525 | * Calculate the group which has the least non-idle load. |
3526 | * This is the group from where we need to pick up the load |
3527 | * for saving power |
3528 | */ |
3529 | if ((sgs->sum_nr_running < sds->min_nr_running) || |
3530 | (sgs->sum_nr_running == sds->min_nr_running && |
3531 | group_first_cpu(group) > group_first_cpu(sds->group_min))) { |
3532 | sds->group_min = group; |
3533 | sds->min_nr_running = sgs->sum_nr_running; |
3534 | sds->min_load_per_task = sgs->sum_weighted_load / |
3535 | sgs->sum_nr_running; |
3536 | } |
3537 | |
3538 | /* |
3539 | * Calculate the group which is almost near its |
3540 | * capacity but still has some space to pick up some load |
3541 | * from other group and save more power |
3542 | */ |
3543 | if (sgs->sum_nr_running + 1 > sgs->group_capacity) |
3544 | return; |
3545 | |
3546 | if (sgs->sum_nr_running > sds->leader_nr_running || |
3547 | (sgs->sum_nr_running == sds->leader_nr_running && |
3548 | group_first_cpu(group) < group_first_cpu(sds->group_leader))) { |
3549 | sds->group_leader = group; |
3550 | sds->leader_nr_running = sgs->sum_nr_running; |
3551 | } |
3552 | } |
3553 | |
3554 | /** |
3555 | * check_power_save_busiest_group - see if there is potential for some power-savings balance |
3556 | * @sds: Variable containing the statistics of the sched_domain |
3557 | * under consideration. |
3558 | * @this_cpu: Cpu at which we're currently performing load-balancing. |
3559 | * @imbalance: Variable to store the imbalance. |
3560 | * |
3561 | * Description: |
3562 | * Check if we have potential to perform some power-savings balance. |
3563 | * If yes, set the busiest group to be the least loaded group in the |
3564 | * sched_domain, so that it's CPUs can be put to idle. |
3565 | * |
3566 | * Returns 1 if there is potential to perform power-savings balance. |
3567 | * Else returns 0. |
3568 | */ |
3569 | static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, |
3570 | int this_cpu, unsigned long *imbalance) |
3571 | { |
3572 | if (!sds->power_savings_balance) |
3573 | return 0; |
3574 | |
3575 | if (sds->this != sds->group_leader || |
3576 | sds->group_leader == sds->group_min) |
3577 | return 0; |
3578 | |
3579 | *imbalance = sds->min_load_per_task; |
3580 | sds->busiest = sds->group_min; |
3581 | |
3582 | return 1; |
3583 | |
3584 | } |
3585 | #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ |
3586 | static inline void init_sd_power_savings_stats(struct sched_domain *sd, |
3587 | struct sd_lb_stats *sds, enum cpu_idle_type idle) |
3588 | { |
3589 | return; |
3590 | } |
3591 | |
3592 | static inline void update_sd_power_savings_stats(struct sched_group *group, |
3593 | struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) |
3594 | { |
3595 | return; |
3596 | } |
3597 | |
3598 | static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, |
3599 | int this_cpu, unsigned long *imbalance) |
3600 | { |
3601 | return 0; |
3602 | } |
3603 | #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ |
3604 | |
3605 | |
3606 | unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) |
3607 | { |
3608 | return SCHED_LOAD_SCALE; |
3609 | } |
3610 | |
3611 | unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) |
3612 | { |
3613 | return default_scale_freq_power(sd, cpu); |
3614 | } |
3615 | |
3616 | unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) |
3617 | { |
3618 | unsigned long weight = cpumask_weight(sched_domain_span(sd)); |
3619 | unsigned long smt_gain = sd->smt_gain; |
3620 | |
3621 | smt_gain /= weight; |
3622 | |
3623 | return smt_gain; |
3624 | } |
3625 | |
3626 | unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu) |
3627 | { |
3628 | return default_scale_smt_power(sd, cpu); |
3629 | } |
3630 | |
3631 | unsigned long scale_rt_power(int cpu) |
3632 | { |
3633 | struct rq *rq = cpu_rq(cpu); |
3634 | u64 total, available; |
3635 | |
3636 | sched_avg_update(rq); |
3637 | |
3638 | total = sched_avg_period() + (rq->clock - rq->age_stamp); |
3639 | available = total - rq->rt_avg; |
3640 | |
3641 | if (unlikely((s64)total < SCHED_LOAD_SCALE)) |
3642 | total = SCHED_LOAD_SCALE; |
3643 | |
3644 | total >>= SCHED_LOAD_SHIFT; |
3645 | |
3646 | return div_u64(available, total); |
3647 | } |
3648 | |
3649 | static void update_cpu_power(struct sched_domain *sd, int cpu) |
3650 | { |
3651 | unsigned long weight = cpumask_weight(sched_domain_span(sd)); |
3652 | unsigned long power = SCHED_LOAD_SCALE; |
3653 | struct sched_group *sdg = sd->groups; |
3654 | |
3655 | if (sched_feat(ARCH_POWER)) |
3656 | power *= arch_scale_freq_power(sd, cpu); |
3657 | else |
3658 | power *= default_scale_freq_power(sd, cpu); |
3659 | |
3660 | power >>= SCHED_LOAD_SHIFT; |
3661 | |
3662 | if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { |
3663 | if (sched_feat(ARCH_POWER)) |
3664 | power *= arch_scale_smt_power(sd, cpu); |
3665 | else |
3666 | power *= default_scale_smt_power(sd, cpu); |
3667 | |
3668 | power >>= SCHED_LOAD_SHIFT; |
3669 | } |
3670 | |
3671 | power *= scale_rt_power(cpu); |
3672 | power >>= SCHED_LOAD_SHIFT; |
3673 | |
3674 | if (!power) |
3675 | power = 1; |
3676 | |
3677 | sdg->cpu_power = power; |
3678 | } |
3679 | |
3680 | static void update_group_power(struct sched_domain *sd, int cpu) |
3681 | { |
3682 | struct sched_domain *child = sd->child; |
3683 | struct sched_group *group, *sdg = sd->groups; |
3684 | unsigned long power; |
3685 | |
3686 | if (!child) { |
3687 | update_cpu_power(sd, cpu); |
3688 | return; |
3689 | } |
3690 | |
3691 | power = 0; |
3692 | |
3693 | group = child->groups; |
3694 | do { |
3695 | power += group->cpu_power; |
3696 | group = group->next; |
3697 | } while (group != child->groups); |
3698 | |
3699 | sdg->cpu_power = power; |
3700 | } |
3701 | |
3702 | /** |
3703 | * update_sg_lb_stats - Update sched_group's statistics for load balancing. |
3704 | * @sd: The sched_domain whose statistics are to be updated. |
3705 | * @group: sched_group whose statistics are to be updated. |
3706 | * @this_cpu: Cpu for which load balance is currently performed. |
3707 | * @idle: Idle status of this_cpu |
3708 | * @load_idx: Load index of sched_domain of this_cpu for load calc. |
3709 | * @sd_idle: Idle status of the sched_domain containing group. |
3710 | * @local_group: Does group contain this_cpu. |
3711 | * @cpus: Set of cpus considered for load balancing. |
3712 | * @balance: Should we balance. |
3713 | * @sgs: variable to hold the statistics for this group. |
3714 | */ |
3715 | static inline void update_sg_lb_stats(struct sched_domain *sd, |
3716 | struct sched_group *group, int this_cpu, |
3717 | enum cpu_idle_type idle, int load_idx, int *sd_idle, |
3718 | int local_group, const struct cpumask *cpus, |
3719 | int *balance, struct sg_lb_stats *sgs) |
3720 | { |
3721 | unsigned long load, max_cpu_load, min_cpu_load; |
3722 | int i; |
3723 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
3724 | unsigned long sum_avg_load_per_task; |
3725 | unsigned long avg_load_per_task; |
3726 | |
3727 | if (local_group) { |
3728 | balance_cpu = group_first_cpu(group); |
3729 | if (balance_cpu == this_cpu) |
3730 | update_group_power(sd, this_cpu); |
3731 | } |
3732 | |
3733 | /* Tally up the load of all CPUs in the group */ |
3734 | sum_avg_load_per_task = avg_load_per_task = 0; |
3735 | max_cpu_load = 0; |
3736 | min_cpu_load = ~0UL; |
3737 | |
3738 | for_each_cpu_and(i, sched_group_cpus(group), cpus) { |
3739 | struct rq *rq = cpu_rq(i); |
3740 | |
3741 | if (*sd_idle && rq->nr_running) |
3742 | *sd_idle = 0; |
3743 | |
3744 | /* Bias balancing toward cpus of our domain */ |
3745 | if (local_group) { |
3746 | if (idle_cpu(i) && !first_idle_cpu) { |
3747 | first_idle_cpu = 1; |
3748 | balance_cpu = i; |
3749 | } |
3750 | |
3751 | load = target_load(i, load_idx); |
3752 | } else { |
3753 | load = source_load(i, load_idx); |
3754 | if (load > max_cpu_load) |
3755 | max_cpu_load = load; |
3756 | if (min_cpu_load > load) |
3757 | min_cpu_load = load; |
3758 | } |
3759 | |
3760 | sgs->group_load += load; |
3761 | sgs->sum_nr_running += rq->nr_running; |
3762 | sgs->sum_weighted_load += weighted_cpuload(i); |
3763 | |
3764 | sum_avg_load_per_task += cpu_avg_load_per_task(i); |
3765 | } |
3766 | |
3767 | /* |
3768 | * First idle cpu or the first cpu(busiest) in this sched group |
3769 | * is eligible for doing load balancing at this and above |
3770 | * domains. In the newly idle case, we will allow all the cpu's |
3771 | * to do the newly idle load balance. |
3772 | */ |
3773 | if (idle != CPU_NEWLY_IDLE && local_group && |
3774 | balance_cpu != this_cpu && balance) { |
3775 | *balance = 0; |
3776 | return; |
3777 | } |
3778 | |
3779 | /* Adjust by relative CPU power of the group */ |
3780 | sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power; |
3781 | |
3782 | |
3783 | /* |
3784 | * Consider the group unbalanced when the imbalance is larger |
3785 | * than the average weight of two tasks. |
3786 | * |
3787 | * APZ: with cgroup the avg task weight can vary wildly and |
3788 | * might not be a suitable number - should we keep a |
3789 | * normalized nr_running number somewhere that negates |
3790 | * the hierarchy? |
3791 | */ |
3792 | avg_load_per_task = (sum_avg_load_per_task * SCHED_LOAD_SCALE) / |
3793 | group->cpu_power; |
3794 | |
3795 | if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) |
3796 | sgs->group_imb = 1; |
3797 | |
3798 | sgs->group_capacity = |
3799 | DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE); |
3800 | } |
3801 | |
3802 | /** |
3803 | * update_sd_lb_stats - Update sched_group's statistics for load balancing. |
3804 | * @sd: sched_domain whose statistics are to be updated. |
3805 | * @this_cpu: Cpu for which load balance is currently performed. |
3806 | * @idle: Idle status of this_cpu |
3807 | * @sd_idle: Idle status of the sched_domain containing group. |
3808 | * @cpus: Set of cpus considered for load balancing. |
3809 | * @balance: Should we balance. |
3810 | * @sds: variable to hold the statistics for this sched_domain. |
3811 | */ |
3812 | static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, |
3813 | enum cpu_idle_type idle, int *sd_idle, |
3814 | const struct cpumask *cpus, int *balance, |
3815 | struct sd_lb_stats *sds) |
3816 | { |
3817 | struct sched_domain *child = sd->child; |
3818 | struct sched_group *group = sd->groups; |
3819 | struct sg_lb_stats sgs; |
3820 | int load_idx, prefer_sibling = 0; |
3821 | |
3822 | if (child && child->flags & SD_PREFER_SIBLING) |
3823 | prefer_sibling = 1; |
3824 | |
3825 | init_sd_power_savings_stats(sd, sds, idle); |
3826 | load_idx = get_sd_load_idx(sd, idle); |
3827 | |
3828 | do { |
3829 | int local_group; |
3830 | |
3831 | local_group = cpumask_test_cpu(this_cpu, |
3832 | sched_group_cpus(group)); |
3833 | memset(&sgs, 0, sizeof(sgs)); |
3834 | update_sg_lb_stats(sd, group, this_cpu, idle, load_idx, sd_idle, |
3835 | local_group, cpus, balance, &sgs); |
3836 | |
3837 | if (local_group && balance && !(*balance)) |
3838 | return; |
3839 | |
3840 | sds->total_load += sgs.group_load; |
3841 | sds->total_pwr += group->cpu_power; |
3842 | |
3843 | /* |
3844 | * In case the child domain prefers tasks go to siblings |
3845 | * first, lower the group capacity to one so that we'll try |
3846 | * and move all the excess tasks away. |
3847 | */ |
3848 | if (prefer_sibling) |
3849 | sgs.group_capacity = min(sgs.group_capacity, 1UL); |
3850 | |
3851 | if (local_group) { |
3852 | sds->this_load = sgs.avg_load; |
3853 | sds->this = group; |
3854 | sds->this_nr_running = sgs.sum_nr_running; |
3855 | sds->this_load_per_task = sgs.sum_weighted_load; |
3856 | } else if (sgs.avg_load > sds->max_load && |
3857 | (sgs.sum_nr_running > sgs.group_capacity || |
3858 | sgs.group_imb)) { |
3859 | sds->max_load = sgs.avg_load; |
3860 | sds->busiest = group; |
3861 | sds->busiest_nr_running = sgs.sum_nr_running; |
3862 | sds->busiest_load_per_task = sgs.sum_weighted_load; |
3863 | sds->group_imb = sgs.group_imb; |
3864 | } |
3865 | |
3866 | update_sd_power_savings_stats(group, sds, local_group, &sgs); |
3867 | group = group->next; |
3868 | } while (group != sd->groups); |
3869 | } |
3870 | |
3871 | /** |
3872 | * fix_small_imbalance - Calculate the minor imbalance that exists |
3873 | * amongst the groups of a sched_domain, during |
3874 | * load balancing. |
3875 | * @sds: Statistics of the sched_domain whose imbalance is to be calculated. |
3876 | * @this_cpu: The cpu at whose sched_domain we're performing load-balance. |
3877 | * @imbalance: Variable to store the imbalance. |
3878 | */ |
3879 | static inline void fix_small_imbalance(struct sd_lb_stats *sds, |
3880 | int this_cpu, unsigned long *imbalance) |
3881 | { |
3882 | unsigned long tmp, pwr_now = 0, pwr_move = 0; |
3883 | unsigned int imbn = 2; |
3884 | |
3885 | if (sds->this_nr_running) { |
3886 | sds->this_load_per_task /= sds->this_nr_running; |
3887 | if (sds->busiest_load_per_task > |
3888 | sds->this_load_per_task) |
3889 | imbn = 1; |
3890 | } else |
3891 | sds->this_load_per_task = |
3892 | cpu_avg_load_per_task(this_cpu); |
3893 | |
3894 | if (sds->max_load - sds->this_load + sds->busiest_load_per_task >= |
3895 | sds->busiest_load_per_task * imbn) { |
3896 | *imbalance = sds->busiest_load_per_task; |
3897 | return; |
3898 | } |
3899 | |
3900 | /* |
3901 | * OK, we don't have enough imbalance to justify moving tasks, |
3902 | * however we may be able to increase total CPU power used by |
3903 | * moving them. |
3904 | */ |
3905 | |
3906 | pwr_now += sds->busiest->cpu_power * |
3907 | min(sds->busiest_load_per_task, sds->max_load); |
3908 | pwr_now += sds->this->cpu_power * |
3909 | min(sds->this_load_per_task, sds->this_load); |
3910 | pwr_now /= SCHED_LOAD_SCALE; |
3911 | |
3912 | /* Amount of load we'd subtract */ |
3913 | tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / |
3914 | sds->busiest->cpu_power; |
3915 | if (sds->max_load > tmp) |
3916 | pwr_move += sds->busiest->cpu_power * |
3917 | min(sds->busiest_load_per_task, sds->max_load - tmp); |
3918 | |
3919 | /* Amount of load we'd add */ |
3920 | if (sds->max_load * sds->busiest->cpu_power < |
3921 | sds->busiest_load_per_task * SCHED_LOAD_SCALE) |
3922 | tmp = (sds->max_load * sds->busiest->cpu_power) / |
3923 | sds->this->cpu_power; |
3924 | else |
3925 | tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / |
3926 | sds->this->cpu_power; |
3927 | pwr_move += sds->this->cpu_power * |
3928 | min(sds->this_load_per_task, sds->this_load + tmp); |
3929 | pwr_move /= SCHED_LOAD_SCALE; |
3930 | |
3931 | /* Move if we gain throughput */ |
3932 | if (pwr_move > pwr_now) |
3933 | *imbalance = sds->busiest_load_per_task; |
3934 | } |
3935 | |
3936 | /** |
3937 | * calculate_imbalance - Calculate the amount of imbalance present within the |
3938 | * groups of a given sched_domain during load balance. |
3939 | * @sds: statistics of the sched_domain whose imbalance is to be calculated. |
3940 | * @this_cpu: Cpu for which currently load balance is being performed. |
3941 | * @imbalance: The variable to store the imbalance. |
3942 | */ |
3943 | static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, |
3944 | unsigned long *imbalance) |
3945 | { |
3946 | unsigned long max_pull; |
3947 | /* |
3948 | * In the presence of smp nice balancing, certain scenarios can have |
3949 | * max load less than avg load(as we skip the groups at or below |
3950 | * its cpu_power, while calculating max_load..) |
3951 | */ |
3952 | if (sds->max_load < sds->avg_load) { |
3953 | *imbalance = 0; |
3954 | return fix_small_imbalance(sds, this_cpu, imbalance); |
3955 | } |
3956 | |
3957 | /* Don't want to pull so many tasks that a group would go idle */ |
3958 | max_pull = min(sds->max_load - sds->avg_load, |
3959 | sds->max_load - sds->busiest_load_per_task); |
3960 | |
3961 | /* How much load to actually move to equalise the imbalance */ |
3962 | *imbalance = min(max_pull * sds->busiest->cpu_power, |
3963 | (sds->avg_load - sds->this_load) * sds->this->cpu_power) |
3964 | / SCHED_LOAD_SCALE; |
3965 | |
3966 | /* |
3967 | * if *imbalance is less than the average load per runnable task |
3968 | * there is no gaurantee that any tasks will be moved so we'll have |
3969 | * a think about bumping its value to force at least one task to be |
3970 | * moved |
3971 | */ |
3972 | if (*imbalance < sds->busiest_load_per_task) |
3973 | return fix_small_imbalance(sds, this_cpu, imbalance); |
3974 | |
3975 | } |
3976 | /******* find_busiest_group() helpers end here *********************/ |
3977 | |
3978 | /** |
3979 | * find_busiest_group - Returns the busiest group within the sched_domain |
3980 | * if there is an imbalance. If there isn't an imbalance, and |
3981 | * the user has opted for power-savings, it returns a group whose |
3982 | * CPUs can be put to idle by rebalancing those tasks elsewhere, if |
3983 | * such a group exists. |
3984 | * |
3985 | * Also calculates the amount of weighted load which should be moved |
3986 | * to restore balance. |
3987 | * |
3988 | * @sd: The sched_domain whose busiest group is to be returned. |
3989 | * @this_cpu: The cpu for which load balancing is currently being performed. |
3990 | * @imbalance: Variable which stores amount of weighted load which should |
3991 | * be moved to restore balance/put a group to idle. |
3992 | * @idle: The idle status of this_cpu. |
3993 | * @sd_idle: The idleness of sd |
3994 | * @cpus: The set of CPUs under consideration for load-balancing. |
3995 | * @balance: Pointer to a variable indicating if this_cpu |
3996 | * is the appropriate cpu to perform load balancing at this_level. |
3997 | * |
3998 | * Returns: - the busiest group if imbalance exists. |
3999 | * - If no imbalance and user has opted for power-savings balance, |
4000 | * return the least loaded group whose CPUs can be |
4001 | * put to idle by rebalancing its tasks onto our group. |
4002 | */ |
4003 | static struct sched_group * |
4004 | find_busiest_group(struct sched_domain *sd, int this_cpu, |
4005 | unsigned long *imbalance, enum cpu_idle_type idle, |
4006 | int *sd_idle, const struct cpumask *cpus, int *balance) |
4007 | { |
4008 | struct sd_lb_stats sds; |
4009 | |
4010 | memset(&sds, 0, sizeof(sds)); |
4011 | |
4012 | /* |
4013 | * Compute the various statistics relavent for load balancing at |
4014 | * this level. |
4015 | */ |
4016 | update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus, |
4017 | balance, &sds); |
4018 | |
4019 | /* Cases where imbalance does not exist from POV of this_cpu */ |
4020 | /* 1) this_cpu is not the appropriate cpu to perform load balancing |
4021 | * at this level. |
4022 | * 2) There is no busy sibling group to pull from. |
4023 | * 3) This group is the busiest group. |
4024 | * 4) This group is more busy than the avg busieness at this |
4025 | * sched_domain. |
4026 | * 5) The imbalance is within the specified limit. |
4027 | * 6) Any rebalance would lead to ping-pong |
4028 | */ |
4029 | if (balance && !(*balance)) |
4030 | goto ret; |
4031 | |
4032 | if (!sds.busiest || sds.busiest_nr_running == 0) |
4033 | goto out_balanced; |
4034 | |
4035 | if (sds.this_load >= sds.max_load) |
4036 | goto out_balanced; |
4037 | |
4038 | sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr; |
4039 | |
4040 | if (sds.this_load >= sds.avg_load) |
4041 | goto out_balanced; |
4042 | |
4043 | if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load) |
4044 | goto out_balanced; |
4045 | |
4046 | sds.busiest_load_per_task /= sds.busiest_nr_running; |
4047 | if (sds.group_imb) |
4048 | sds.busiest_load_per_task = |
4049 | min(sds.busiest_load_per_task, sds.avg_load); |
4050 | |
4051 | /* |
4052 | * We're trying to get all the cpus to the average_load, so we don't |
4053 | * want to push ourselves above the average load, nor do we wish to |
4054 | * reduce the max loaded cpu below the average load, as either of these |
4055 | * actions would just result in more rebalancing later, and ping-pong |
4056 | * tasks around. Thus we look for the minimum possible imbalance. |
4057 | * Negative imbalances (*we* are more loaded than anyone else) will |
4058 | * be counted as no imbalance for these purposes -- we can't fix that |
4059 | * by pulling tasks to us. Be careful of negative numbers as they'll |
4060 | * appear as very large values with unsigned longs. |
4061 | */ |
4062 | if (sds.max_load <= sds.busiest_load_per_task) |
4063 | goto out_balanced; |
4064 | |
4065 | /* Looks like there is an imbalance. Compute it */ |
4066 | calculate_imbalance(&sds, this_cpu, imbalance); |
4067 | return sds.busiest; |
4068 | |
4069 | out_balanced: |
4070 | /* |
4071 | * There is no obvious imbalance. But check if we can do some balancing |
4072 | * to save power. |
4073 | */ |
4074 | if (check_power_save_busiest_group(&sds, this_cpu, imbalance)) |
4075 | return sds.busiest; |
4076 | ret: |
4077 | *imbalance = 0; |
4078 | return NULL; |
4079 | } |
4080 | |
4081 | /* |
4082 | * find_busiest_queue - find the busiest runqueue among the cpus in group. |
4083 | */ |
4084 | static struct rq * |
4085 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
4086 | unsigned long imbalance, const struct cpumask *cpus) |
4087 | { |
4088 | struct rq *busiest = NULL, *rq; |
4089 | unsigned long max_load = 0; |
4090 | int i; |
4091 | |
4092 | for_each_cpu(i, sched_group_cpus(group)) { |
4093 | unsigned long power = power_of(i); |
4094 | unsigned long capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE); |
4095 | unsigned long wl; |
4096 | |
4097 | if (!cpumask_test_cpu(i, cpus)) |
4098 | continue; |
4099 | |
4100 | rq = cpu_rq(i); |
4101 | wl = weighted_cpuload(i); |
4102 | |
4103 | /* |
4104 | * When comparing with imbalance, use weighted_cpuload() |
4105 | * which is not scaled with the cpu power. |
4106 | */ |
4107 | if (capacity && rq->nr_running == 1 && wl > imbalance) |
4108 | continue; |
4109 | |
4110 | /* |
4111 | * For the load comparisons with the other cpu's, consider |
4112 | * the weighted_cpuload() scaled with the cpu power, so that |
4113 | * the load can be moved away from the cpu that is potentially |
4114 | * running at a lower capacity. |
4115 | */ |
4116 | wl = (wl * SCHED_LOAD_SCALE) / power; |
4117 | |
4118 | if (wl > max_load) { |
4119 | max_load = wl; |
4120 | busiest = rq; |
4121 | } |
4122 | } |
4123 | |
4124 | return busiest; |
4125 | } |
4126 | |
4127 | /* |
4128 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but |
4129 | * so long as it is large enough. |
4130 | */ |
4131 | #define MAX_PINNED_INTERVAL 512 |
4132 | |
4133 | /* Working cpumask for load_balance and load_balance_newidle. */ |
4134 | static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask); |
4135 | |
4136 | /* |
4137 | * Check this_cpu to ensure it is balanced within domain. Attempt to move |
4138 | * tasks if there is an imbalance. |
4139 | */ |
4140 | static int load_balance(int this_cpu, struct rq *this_rq, |
4141 | struct sched_domain *sd, enum cpu_idle_type idle, |
4142 | int *balance) |
4143 | { |
4144 | int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
4145 | struct sched_group *group; |
4146 | unsigned long imbalance; |
4147 | struct rq *busiest; |
4148 | unsigned long flags; |
4149 | struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); |
4150 | |
4151 | cpumask_copy(cpus, cpu_active_mask); |
4152 | |
4153 | /* |
4154 | * When power savings policy is enabled for the parent domain, idle |
4155 | * sibling can pick up load irrespective of busy siblings. In this case, |
4156 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
4157 | * portraying it as CPU_NOT_IDLE. |
4158 | */ |
4159 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
4160 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
4161 | sd_idle = 1; |
4162 | |
4163 | schedstat_inc(sd, lb_count[idle]); |
4164 | |
4165 | redo: |
4166 | update_shares(sd); |
4167 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, |
4168 | cpus, balance); |
4169 | |
4170 | if (*balance == 0) |
4171 | goto out_balanced; |
4172 | |
4173 | if (!group) { |
4174 | schedstat_inc(sd, lb_nobusyg[idle]); |
4175 | goto out_balanced; |
4176 | } |
4177 | |
4178 | busiest = find_busiest_queue(group, idle, imbalance, cpus); |
4179 | if (!busiest) { |
4180 | schedstat_inc(sd, lb_nobusyq[idle]); |
4181 | goto out_balanced; |
4182 | } |
4183 | |
4184 | BUG_ON(busiest == this_rq); |
4185 | |
4186 | schedstat_add(sd, lb_imbalance[idle], imbalance); |
4187 | |
4188 | ld_moved = 0; |
4189 | if (busiest->nr_running > 1) { |
4190 | /* |
4191 | * Attempt to move tasks. If find_busiest_group has found |
4192 | * an imbalance but busiest->nr_running <= 1, the group is |
4193 | * still unbalanced. ld_moved simply stays zero, so it is |
4194 | * correctly treated as an imbalance. |
4195 | */ |
4196 | local_irq_save(flags); |
4197 | double_rq_lock(this_rq, busiest); |
4198 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
4199 | imbalance, sd, idle, &all_pinned); |
4200 | double_rq_unlock(this_rq, busiest); |
4201 | local_irq_restore(flags); |
4202 | |
4203 | /* |
4204 | * some other cpu did the load balance for us. |
4205 | */ |
4206 | if (ld_moved && this_cpu != smp_processor_id()) |
4207 | resched_cpu(this_cpu); |
4208 | |
4209 | /* All tasks on this runqueue were pinned by CPU affinity */ |
4210 | if (unlikely(all_pinned)) { |
4211 | cpumask_clear_cpu(cpu_of(busiest), cpus); |
4212 | if (!cpumask_empty(cpus)) |
4213 | goto redo; |
4214 | goto out_balanced; |
4215 | } |
4216 | } |
4217 | |
4218 | if (!ld_moved) { |
4219 | schedstat_inc(sd, lb_failed[idle]); |
4220 | sd->nr_balance_failed++; |
4221 | |
4222 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { |
4223 | |
4224 | spin_lock_irqsave(&busiest->lock, flags); |
4225 | |
4226 | /* don't kick the migration_thread, if the curr |
4227 | * task on busiest cpu can't be moved to this_cpu |
4228 | */ |
4229 | if (!cpumask_test_cpu(this_cpu, |
4230 | &busiest->curr->cpus_allowed)) { |
4231 | spin_unlock_irqrestore(&busiest->lock, flags); |
4232 | all_pinned = 1; |
4233 | goto out_one_pinned; |
4234 | } |
4235 | |
4236 | if (!busiest->active_balance) { |
4237 | busiest->active_balance = 1; |
4238 | busiest->push_cpu = this_cpu; |
4239 | active_balance = 1; |
4240 | } |
4241 | spin_unlock_irqrestore(&busiest->lock, flags); |
4242 | if (active_balance) |
4243 | wake_up_process(busiest->migration_thread); |
4244 | |
4245 | /* |
4246 | * We've kicked active balancing, reset the failure |
4247 | * counter. |
4248 | */ |
4249 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
4250 | } |
4251 | } else |
4252 | sd->nr_balance_failed = 0; |
4253 | |
4254 | if (likely(!active_balance)) { |
4255 | /* We were unbalanced, so reset the balancing interval */ |
4256 | sd->balance_interval = sd->min_interval; |
4257 | } else { |
4258 | /* |
4259 | * If we've begun active balancing, start to back off. This |
4260 | * case may not be covered by the all_pinned logic if there |
4261 | * is only 1 task on the busy runqueue (because we don't call |
4262 | * move_tasks). |
4263 | */ |
4264 | if (sd->balance_interval < sd->max_interval) |
4265 | sd->balance_interval *= 2; |
4266 | } |
4267 | |
4268 | if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
4269 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
4270 | ld_moved = -1; |
4271 | |
4272 | goto out; |
4273 | |
4274 | out_balanced: |
4275 | schedstat_inc(sd, lb_balanced[idle]); |
4276 | |
4277 | sd->nr_balance_failed = 0; |
4278 | |
4279 | out_one_pinned: |
4280 | /* tune up the balancing interval */ |
4281 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
4282 | (sd->balance_interval < sd->max_interval)) |
4283 | sd->balance_interval *= 2; |
4284 | |
4285 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
4286 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
4287 | ld_moved = -1; |
4288 | else |
4289 | ld_moved = 0; |
4290 | out: |
4291 | if (ld_moved) |
4292 | update_shares(sd); |
4293 | return ld_moved; |
4294 | } |
4295 | |
4296 | /* |
4297 | * Check this_cpu to ensure it is balanced within domain. Attempt to move |
4298 | * tasks if there is an imbalance. |
4299 | * |
4300 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
4301 | * this_rq is locked. |
4302 | */ |
4303 | static int |
4304 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
4305 | { |
4306 | struct sched_group *group; |
4307 | struct rq *busiest = NULL; |
4308 | unsigned long imbalance; |
4309 | int ld_moved = 0; |
4310 | int sd_idle = 0; |
4311 | int all_pinned = 0; |
4312 | struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); |
4313 | |
4314 | cpumask_copy(cpus, cpu_active_mask); |
4315 | |
4316 | /* |
4317 | * When power savings policy is enabled for the parent domain, idle |
4318 | * sibling can pick up load irrespective of busy siblings. In this case, |
4319 | * let the state of idle sibling percolate up as IDLE, instead of |
4320 | * portraying it as CPU_NOT_IDLE. |
4321 | */ |
4322 | if (sd->flags & SD_SHARE_CPUPOWER && |
4323 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
4324 | sd_idle = 1; |
4325 | |
4326 | schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); |
4327 | redo: |
4328 | update_shares_locked(this_rq, sd); |
4329 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
4330 | &sd_idle, cpus, NULL); |
4331 | if (!group) { |
4332 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
4333 | goto out_balanced; |
4334 | } |
4335 | |
4336 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus); |
4337 | if (!busiest) { |
4338 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
4339 | goto out_balanced; |
4340 | } |
4341 | |
4342 | BUG_ON(busiest == this_rq); |
4343 | |
4344 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
4345 | |
4346 | ld_moved = 0; |
4347 | if (busiest->nr_running > 1) { |
4348 | /* Attempt to move tasks */ |
4349 | double_lock_balance(this_rq, busiest); |
4350 | /* this_rq->clock is already updated */ |
4351 | update_rq_clock(busiest); |
4352 | ld_moved = move_tasks(this_rq, this_cpu, busiest, |
4353 | imbalance, sd, CPU_NEWLY_IDLE, |
4354 | &all_pinned); |
4355 | double_unlock_balance(this_rq, busiest); |
4356 | |
4357 | if (unlikely(all_pinned)) { |
4358 | cpumask_clear_cpu(cpu_of(busiest), cpus); |
4359 | if (!cpumask_empty(cpus)) |
4360 | goto redo; |
4361 | } |
4362 | } |
4363 | |
4364 | if (!ld_moved) { |
4365 | int active_balance = 0; |
4366 | |
4367 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
4368 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
4369 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
4370 | return -1; |
4371 | |
4372 | if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP) |
4373 | return -1; |
4374 | |
4375 | if (sd->nr_balance_failed++ < 2) |
4376 | return -1; |
4377 | |
4378 | /* |
4379 | * The only task running in a non-idle cpu can be moved to this |
4380 | * cpu in an attempt to completely freeup the other CPU |
4381 | * package. The same method used to move task in load_balance() |
4382 | * have been extended for load_balance_newidle() to speedup |
4383 | * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2) |
4384 | * |
4385 | * The package power saving logic comes from |
4386 | * find_busiest_group(). If there are no imbalance, then |
4387 | * f_b_g() will return NULL. However when sched_mc={1,2} then |
4388 | * f_b_g() will select a group from which a running task may be |
4389 | * pulled to this cpu in order to make the other package idle. |
4390 | * If there is no opportunity to make a package idle and if |
4391 | * there are no imbalance, then f_b_g() will return NULL and no |
4392 | * action will be taken in load_balance_newidle(). |
4393 | * |
4394 | * Under normal task pull operation due to imbalance, there |
4395 | * will be more than one task in the source run queue and |
4396 | * move_tasks() will succeed. ld_moved will be true and this |
4397 | * active balance code will not be triggered. |
4398 | */ |
4399 | |
4400 | /* Lock busiest in correct order while this_rq is held */ |
4401 | double_lock_balance(this_rq, busiest); |
4402 | |
4403 | /* |
4404 | * don't kick the migration_thread, if the curr |
4405 | * task on busiest cpu can't be moved to this_cpu |
4406 | */ |
4407 | if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) { |
4408 | double_unlock_balance(this_rq, busiest); |
4409 | all_pinned = 1; |
4410 | return ld_moved; |
4411 | } |
4412 | |
4413 | if (!busiest->active_balance) { |
4414 | busiest->active_balance = 1; |
4415 | busiest->push_cpu = this_cpu; |
4416 | active_balance = 1; |
4417 | } |
4418 | |
4419 | double_unlock_balance(this_rq, busiest); |
4420 | /* |
4421 | * Should not call ttwu while holding a rq->lock |
4422 | */ |
4423 | spin_unlock(&this_rq->lock); |
4424 | if (active_balance) |
4425 | wake_up_process(busiest->migration_thread); |
4426 | spin_lock(&this_rq->lock); |
4427 | |
4428 | } else |
4429 | sd->nr_balance_failed = 0; |
4430 | |
4431 | update_shares_locked(this_rq, sd); |
4432 | return ld_moved; |
4433 | |
4434 | out_balanced: |
4435 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
4436 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
4437 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
4438 | return -1; |
4439 | sd->nr_balance_failed = 0; |
4440 | |
4441 | return 0; |
4442 | } |
4443 | |
4444 | /* |
4445 | * idle_balance is called by schedule() if this_cpu is about to become |
4446 | * idle. Attempts to pull tasks from other CPUs. |
4447 | */ |
4448 | static void idle_balance(int this_cpu, struct rq *this_rq) |
4449 | { |
4450 | struct sched_domain *sd; |
4451 | int pulled_task = 0; |
4452 | unsigned long next_balance = jiffies + HZ; |
4453 | |
4454 | this_rq->idle_stamp = this_rq->clock; |
4455 | |
4456 | if (this_rq->avg_idle < sysctl_sched_migration_cost) |
4457 | return; |
4458 | |
4459 | for_each_domain(this_cpu, sd) { |
4460 | unsigned long interval; |
4461 | |
4462 | if (!(sd->flags & SD_LOAD_BALANCE)) |
4463 | continue; |
4464 | |
4465 | if (sd->flags & SD_BALANCE_NEWIDLE) |
4466 | /* If we've pulled tasks over stop searching: */ |
4467 | pulled_task = load_balance_newidle(this_cpu, this_rq, |
4468 | sd); |
4469 | |
4470 | interval = msecs_to_jiffies(sd->balance_interval); |
4471 | if (time_after(next_balance, sd->last_balance + interval)) |
4472 | next_balance = sd->last_balance + interval; |
4473 | if (pulled_task) { |
4474 | this_rq->idle_stamp = 0; |
4475 | break; |
4476 | } |
4477 | } |
4478 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
4479 | /* |
4480 | * We are going idle. next_balance may be set based on |
4481 | * a busy processor. So reset next_balance. |
4482 | */ |
4483 | this_rq->next_balance = next_balance; |
4484 | } |
4485 | } |
4486 | |
4487 | /* |
4488 | * active_load_balance is run by migration threads. It pushes running tasks |
4489 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be |
4490 | * running on each physical CPU where possible, and avoids physical / |
4491 | * logical imbalances. |
4492 | * |
4493 | * Called with busiest_rq locked. |
4494 | */ |
4495 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
4496 | { |
4497 | int target_cpu = busiest_rq->push_cpu; |
4498 | struct sched_domain *sd; |
4499 | struct rq *target_rq; |
4500 | |
4501 | /* Is there any task to move? */ |
4502 | if (busiest_rq->nr_running <= 1) |
4503 | return; |
4504 | |
4505 | target_rq = cpu_rq(target_cpu); |
4506 | |
4507 | /* |
4508 | * This condition is "impossible", if it occurs |
4509 | * we need to fix it. Originally reported by |
4510 | * Bjorn Helgaas on a 128-cpu setup. |
4511 | */ |
4512 | BUG_ON(busiest_rq == target_rq); |
4513 | |
4514 | /* move a task from busiest_rq to target_rq */ |
4515 | double_lock_balance(busiest_rq, target_rq); |
4516 | update_rq_clock(busiest_rq); |
4517 | update_rq_clock(target_rq); |
4518 | |
4519 | /* Search for an sd spanning us and the target CPU. */ |
4520 | for_each_domain(target_cpu, sd) { |
4521 | if ((sd->flags & SD_LOAD_BALANCE) && |
4522 | cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) |
4523 | break; |
4524 | } |
4525 | |
4526 | if (likely(sd)) { |
4527 | schedstat_inc(sd, alb_count); |
4528 | |
4529 | if (move_one_task(target_rq, target_cpu, busiest_rq, |
4530 | sd, CPU_IDLE)) |
4531 | schedstat_inc(sd, alb_pushed); |
4532 | else |
4533 | schedstat_inc(sd, alb_failed); |
4534 | } |
4535 | double_unlock_balance(busiest_rq, target_rq); |
4536 | } |
4537 | |
4538 | #ifdef CONFIG_NO_HZ |
4539 | static struct { |
4540 | atomic_t load_balancer; |
4541 | cpumask_var_t cpu_mask; |
4542 | cpumask_var_t ilb_grp_nohz_mask; |
4543 | } nohz ____cacheline_aligned = { |
4544 | .load_balancer = ATOMIC_INIT(-1), |
4545 | }; |
4546 | |
4547 | int get_nohz_load_balancer(void) |
4548 | { |
4549 | return atomic_read(&nohz.load_balancer); |
4550 | } |
4551 | |
4552 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
4553 | /** |
4554 | * lowest_flag_domain - Return lowest sched_domain containing flag. |
4555 | * @cpu: The cpu whose lowest level of sched domain is to |
4556 | * be returned. |
4557 | * @flag: The flag to check for the lowest sched_domain |
4558 | * for the given cpu. |
4559 | * |
4560 | * Returns the lowest sched_domain of a cpu which contains the given flag. |
4561 | */ |
4562 | static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) |
4563 | { |
4564 | struct sched_domain *sd; |
4565 | |
4566 | for_each_domain(cpu, sd) |
4567 | if (sd && (sd->flags & flag)) |
4568 | break; |
4569 | |
4570 | return sd; |
4571 | } |
4572 | |
4573 | /** |
4574 | * for_each_flag_domain - Iterates over sched_domains containing the flag. |
4575 | * @cpu: The cpu whose domains we're iterating over. |
4576 | * @sd: variable holding the value of the power_savings_sd |
4577 | * for cpu. |
4578 | * @flag: The flag to filter the sched_domains to be iterated. |
4579 | * |
4580 | * Iterates over all the scheduler domains for a given cpu that has the 'flag' |
4581 | * set, starting from the lowest sched_domain to the highest. |
4582 | */ |
4583 | #define for_each_flag_domain(cpu, sd, flag) \ |
4584 | for (sd = lowest_flag_domain(cpu, flag); \ |
4585 | (sd && (sd->flags & flag)); sd = sd->parent) |
4586 | |
4587 | /** |
4588 | * is_semi_idle_group - Checks if the given sched_group is semi-idle. |
4589 | * @ilb_group: group to be checked for semi-idleness |
4590 | * |
4591 | * Returns: 1 if the group is semi-idle. 0 otherwise. |
4592 | * |
4593 | * We define a sched_group to be semi idle if it has atleast one idle-CPU |
4594 | * and atleast one non-idle CPU. This helper function checks if the given |
4595 | * sched_group is semi-idle or not. |
4596 | */ |
4597 | static inline int is_semi_idle_group(struct sched_group *ilb_group) |
4598 | { |
4599 | cpumask_and(nohz.ilb_grp_nohz_mask, nohz.cpu_mask, |
4600 | sched_group_cpus(ilb_group)); |
4601 | |
4602 | /* |
4603 | * A sched_group is semi-idle when it has atleast one busy cpu |
4604 | * and atleast one idle cpu. |
4605 | */ |
4606 | if (cpumask_empty(nohz.ilb_grp_nohz_mask)) |
4607 | return 0; |
4608 | |
4609 | if (cpumask_equal(nohz.ilb_grp_nohz_mask, sched_group_cpus(ilb_group))) |
4610 | return 0; |
4611 | |
4612 | return 1; |
4613 | } |
4614 | /** |
4615 | * find_new_ilb - Finds the optimum idle load balancer for nomination. |
4616 | * @cpu: The cpu which is nominating a new idle_load_balancer. |
4617 | * |
4618 | * Returns: Returns the id of the idle load balancer if it exists, |
4619 | * Else, returns >= nr_cpu_ids. |
4620 | * |
4621 | * This algorithm picks the idle load balancer such that it belongs to a |
4622 | * semi-idle powersavings sched_domain. The idea is to try and avoid |
4623 | * completely idle packages/cores just for the purpose of idle load balancing |
4624 | * when there are other idle cpu's which are better suited for that job. |
4625 | */ |
4626 | static int find_new_ilb(int cpu) |
4627 | { |
4628 | struct sched_domain *sd; |
4629 | struct sched_group *ilb_group; |
4630 | |
4631 | /* |
4632 | * Have idle load balancer selection from semi-idle packages only |
4633 | * when power-aware load balancing is enabled |
4634 | */ |
4635 | if (!(sched_smt_power_savings || sched_mc_power_savings)) |
4636 | goto out_done; |
4637 | |
4638 | /* |
4639 | * Optimize for the case when we have no idle CPUs or only one |
4640 | * idle CPU. Don't walk the sched_domain hierarchy in such cases |
4641 | */ |
4642 | if (cpumask_weight(nohz.cpu_mask) < 2) |
4643 | goto out_done; |
4644 | |
4645 | for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { |
4646 | ilb_group = sd->groups; |
4647 | |
4648 | do { |
4649 | if (is_semi_idle_group(ilb_group)) |
4650 | return cpumask_first(nohz.ilb_grp_nohz_mask); |
4651 | |
4652 | ilb_group = ilb_group->next; |
4653 | |
4654 | } while (ilb_group != sd->groups); |
4655 | } |
4656 | |
4657 | out_done: |
4658 | return cpumask_first(nohz.cpu_mask); |
4659 | } |
4660 | #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ |
4661 | static inline int find_new_ilb(int call_cpu) |
4662 | { |
4663 | return cpumask_first(nohz.cpu_mask); |
4664 | } |
4665 | #endif |
4666 | |
4667 | /* |
4668 | * This routine will try to nominate the ilb (idle load balancing) |
4669 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle |
4670 | * load balancing on behalf of all those cpus. If all the cpus in the system |
4671 | * go into this tickless mode, then there will be no ilb owner (as there is |
4672 | * no need for one) and all the cpus will sleep till the next wakeup event |
4673 | * arrives... |
4674 | * |
4675 | * For the ilb owner, tick is not stopped. And this tick will be used |
4676 | * for idle load balancing. ilb owner will still be part of |
4677 | * nohz.cpu_mask.. |
4678 | * |
4679 | * While stopping the tick, this cpu will become the ilb owner if there |
4680 | * is no other owner. And will be the owner till that cpu becomes busy |
4681 | * or if all cpus in the system stop their ticks at which point |
4682 | * there is no need for ilb owner. |
4683 | * |
4684 | * When the ilb owner becomes busy, it nominates another owner, during the |
4685 | * next busy scheduler_tick() |
4686 | */ |
4687 | int select_nohz_load_balancer(int stop_tick) |
4688 | { |
4689 | int cpu = smp_processor_id(); |
4690 | |
4691 | if (stop_tick) { |
4692 | cpu_rq(cpu)->in_nohz_recently = 1; |
4693 | |
4694 | if (!cpu_active(cpu)) { |
4695 | if (atomic_read(&nohz.load_balancer) != cpu) |
4696 | return 0; |
4697 | |
4698 | /* |
4699 | * If we are going offline and still the leader, |
4700 | * give up! |
4701 | */ |
4702 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) |
4703 | BUG(); |
4704 | |
4705 | return 0; |
4706 | } |
4707 | |
4708 | cpumask_set_cpu(cpu, nohz.cpu_mask); |
4709 | |
4710 | /* time for ilb owner also to sleep */ |
4711 | if (cpumask_weight(nohz.cpu_mask) == num_active_cpus()) { |
4712 | if (atomic_read(&nohz.load_balancer) == cpu) |
4713 | atomic_set(&nohz.load_balancer, -1); |
4714 | return 0; |
4715 | } |
4716 | |
4717 | if (atomic_read(&nohz.load_balancer) == -1) { |
4718 | /* make me the ilb owner */ |
4719 | if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) |
4720 | return 1; |
4721 | } else if (atomic_read(&nohz.load_balancer) == cpu) { |
4722 | int new_ilb; |
4723 | |
4724 | if (!(sched_smt_power_savings || |
4725 | sched_mc_power_savings)) |
4726 | return 1; |
4727 | /* |
4728 | * Check to see if there is a more power-efficient |
4729 | * ilb. |
4730 | */ |
4731 | new_ilb = find_new_ilb(cpu); |
4732 | if (new_ilb < nr_cpu_ids && new_ilb != cpu) { |
4733 | atomic_set(&nohz.load_balancer, -1); |
4734 | resched_cpu(new_ilb); |
4735 | return 0; |
4736 | } |
4737 | return 1; |
4738 | } |
4739 | } else { |
4740 | if (!cpumask_test_cpu(cpu, nohz.cpu_mask)) |
4741 | return 0; |
4742 | |
4743 | cpumask_clear_cpu(cpu, nohz.cpu_mask); |
4744 | |
4745 | if (atomic_read(&nohz.load_balancer) == cpu) |
4746 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) |
4747 | BUG(); |
4748 | } |
4749 | return 0; |
4750 | } |
4751 | #endif |
4752 | |
4753 | static DEFINE_SPINLOCK(balancing); |
4754 | |
4755 | /* |
4756 | * It checks each scheduling domain to see if it is due to be balanced, |
4757 | * and initiates a balancing operation if so. |
4758 | * |
4759 | * Balancing parameters are set up in arch_init_sched_domains. |
4760 | */ |
4761 | static void rebalance_domains(int cpu, enum cpu_idle_type idle) |
4762 | { |
4763 | int balance = 1; |
4764 | struct rq *rq = cpu_rq(cpu); |
4765 | unsigned long interval; |
4766 | struct sched_domain *sd; |
4767 | /* Earliest time when we have to do rebalance again */ |
4768 | unsigned long next_balance = jiffies + 60*HZ; |
4769 | int update_next_balance = 0; |
4770 | int need_serialize; |
4771 | |
4772 | for_each_domain(cpu, sd) { |
4773 | if (!(sd->flags & SD_LOAD_BALANCE)) |
4774 | continue; |
4775 | |
4776 | interval = sd->balance_interval; |
4777 | if (idle != CPU_IDLE) |
4778 | interval *= sd->busy_factor; |
4779 | |
4780 | /* scale ms to jiffies */ |
4781 | interval = msecs_to_jiffies(interval); |
4782 | if (unlikely(!interval)) |
4783 | interval = 1; |
4784 | if (interval > HZ*NR_CPUS/10) |
4785 | interval = HZ*NR_CPUS/10; |
4786 | |
4787 | need_serialize = sd->flags & SD_SERIALIZE; |
4788 | |
4789 | if (need_serialize) { |
4790 | if (!spin_trylock(&balancing)) |
4791 | goto out; |
4792 | } |
4793 | |
4794 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
4795 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
4796 | /* |
4797 | * We've pulled tasks over so either we're no |
4798 | * longer idle, or one of our SMT siblings is |
4799 | * not idle. |
4800 | */ |
4801 | idle = CPU_NOT_IDLE; |
4802 | } |
4803 | sd->last_balance = jiffies; |
4804 | } |
4805 | if (need_serialize) |
4806 | spin_unlock(&balancing); |
4807 | out: |
4808 | if (time_after(next_balance, sd->last_balance + interval)) { |
4809 | next_balance = sd->last_balance + interval; |
4810 | update_next_balance = 1; |
4811 | } |
4812 | |
4813 | /* |
4814 | * Stop the load balance at this level. There is another |
4815 | * CPU in our sched group which is doing load balancing more |
4816 | * actively. |
4817 | */ |
4818 | if (!balance) |
4819 | break; |
4820 | } |
4821 | |
4822 | /* |
4823 | * next_balance will be updated only when there is a need. |
4824 | * When the cpu is attached to null domain for ex, it will not be |
4825 | * updated. |
4826 | */ |
4827 | if (likely(update_next_balance)) |
4828 | rq->next_balance = next_balance; |
4829 | } |
4830 | |
4831 | /* |
4832 | * run_rebalance_domains is triggered when needed from the scheduler tick. |
4833 | * In CONFIG_NO_HZ case, the idle load balance owner will do the |
4834 | * rebalancing for all the cpus for whom scheduler ticks are stopped. |
4835 | */ |
4836 | static void run_rebalance_domains(struct softirq_action *h) |
4837 | { |
4838 | int this_cpu = smp_processor_id(); |
4839 | struct rq *this_rq = cpu_rq(this_cpu); |
4840 | enum cpu_idle_type idle = this_rq->idle_at_tick ? |
4841 | CPU_IDLE : CPU_NOT_IDLE; |
4842 | |
4843 | rebalance_domains(this_cpu, idle); |
4844 | |
4845 | #ifdef CONFIG_NO_HZ |
4846 | /* |
4847 | * If this cpu is the owner for idle load balancing, then do the |
4848 | * balancing on behalf of the other idle cpus whose ticks are |
4849 | * stopped. |
4850 | */ |
4851 | if (this_rq->idle_at_tick && |
4852 | atomic_read(&nohz.load_balancer) == this_cpu) { |
4853 | struct rq *rq; |
4854 | int balance_cpu; |
4855 | |
4856 | for_each_cpu(balance_cpu, nohz.cpu_mask) { |
4857 | if (balance_cpu == this_cpu) |
4858 | continue; |
4859 | |
4860 | /* |
4861 | * If this cpu gets work to do, stop the load balancing |
4862 | * work being done for other cpus. Next load |
4863 | * balancing owner will pick it up. |
4864 | */ |
4865 | if (need_resched()) |
4866 | break; |
4867 | |
4868 | rebalance_domains(balance_cpu, CPU_IDLE); |
4869 | |
4870 | rq = cpu_rq(balance_cpu); |
4871 | if (time_after(this_rq->next_balance, rq->next_balance)) |
4872 | this_rq->next_balance = rq->next_balance; |
4873 | } |
4874 | } |
4875 | #endif |
4876 | } |
4877 | |
4878 | static inline int on_null_domain(int cpu) |
4879 | { |
4880 | return !rcu_dereference(cpu_rq(cpu)->sd); |
4881 | } |
4882 | |
4883 | /* |
4884 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. |
4885 | * |
4886 | * In case of CONFIG_NO_HZ, this is the place where we nominate a new |
4887 | * idle load balancing owner or decide to stop the periodic load balancing, |
4888 | * if the whole system is idle. |
4889 | */ |
4890 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
4891 | { |
4892 | #ifdef CONFIG_NO_HZ |
4893 | /* |
4894 | * If we were in the nohz mode recently and busy at the current |
4895 | * scheduler tick, then check if we need to nominate new idle |
4896 | * load balancer. |
4897 | */ |
4898 | if (rq->in_nohz_recently && !rq->idle_at_tick) { |
4899 | rq->in_nohz_recently = 0; |
4900 | |
4901 | if (atomic_read(&nohz.load_balancer) == cpu) { |
4902 | cpumask_clear_cpu(cpu, nohz.cpu_mask); |
4903 | atomic_set(&nohz.load_balancer, -1); |
4904 | } |
4905 | |
4906 | if (atomic_read(&nohz.load_balancer) == -1) { |
4907 | int ilb = find_new_ilb(cpu); |
4908 | |
4909 | if (ilb < nr_cpu_ids) |
4910 | resched_cpu(ilb); |
4911 | } |
4912 | } |
4913 | |
4914 | /* |
4915 | * If this cpu is idle and doing idle load balancing for all the |
4916 | * cpus with ticks stopped, is it time for that to stop? |
4917 | */ |
4918 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && |
4919 | cpumask_weight(nohz.cpu_mask) == num_online_cpus()) { |
4920 | resched_cpu(cpu); |
4921 | return; |
4922 | } |
4923 | |
4924 | /* |
4925 | * If this cpu is idle and the idle load balancing is done by |
4926 | * someone else, then no need raise the SCHED_SOFTIRQ |
4927 | */ |
4928 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && |
4929 | cpumask_test_cpu(cpu, nohz.cpu_mask)) |
4930 | return; |
4931 | #endif |
4932 | /* Don't need to rebalance while attached to NULL domain */ |
4933 | if (time_after_eq(jiffies, rq->next_balance) && |
4934 | likely(!on_null_domain(cpu))) |
4935 | raise_softirq(SCHED_SOFTIRQ); |
4936 | } |
4937 | |
4938 | #else /* CONFIG_SMP */ |
4939 | |
4940 | /* |
4941 | * on UP we do not need to balance between CPUs: |
4942 | */ |
4943 | static inline void idle_balance(int cpu, struct rq *rq) |
4944 | { |
4945 | } |
4946 | |
4947 | #endif |
4948 | |
4949 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
4950 | |
4951 | EXPORT_PER_CPU_SYMBOL(kstat); |
4952 | |
4953 | /* |
4954 | * Return any ns on the sched_clock that have not yet been accounted in |
4955 | * @p in case that task is currently running. |
4956 | * |
4957 | * Called with task_rq_lock() held on @rq. |
4958 | */ |
4959 | static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) |
4960 | { |
4961 | u64 ns = 0; |
4962 | |
4963 | if (task_current(rq, p)) { |
4964 | update_rq_clock(rq); |
4965 | ns = rq->clock - p->se.exec_start; |
4966 | if ((s64)ns < 0) |
4967 | ns = 0; |
4968 | } |
4969 | |
4970 | return ns; |
4971 | } |
4972 | |
4973 | unsigned long long task_delta_exec(struct task_struct *p) |
4974 | { |
4975 | unsigned long flags; |
4976 | struct rq *rq; |
4977 | u64 ns = 0; |
4978 | |
4979 | rq = task_rq_lock(p, &flags); |
4980 | ns = do_task_delta_exec(p, rq); |
4981 | task_rq_unlock(rq, &flags); |
4982 | |
4983 | return ns; |
4984 | } |
4985 | |
4986 | /* |
4987 | * Return accounted runtime for the task. |
4988 | * In case the task is currently running, return the runtime plus current's |
4989 | * pending runtime that have not been accounted yet. |
4990 | */ |
4991 | unsigned long long task_sched_runtime(struct task_struct *p) |
4992 | { |
4993 | unsigned long flags; |
4994 | struct rq *rq; |
4995 | u64 ns = 0; |
4996 | |
4997 | rq = task_rq_lock(p, &flags); |
4998 | ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); |
4999 | task_rq_unlock(rq, &flags); |
5000 | |
5001 | return ns; |
5002 | } |
5003 | |
5004 | /* |
5005 | * Return sum_exec_runtime for the thread group. |
5006 | * In case the task is currently running, return the sum plus current's |
5007 | * pending runtime that have not been accounted yet. |
5008 | * |
5009 | * Note that the thread group might have other running tasks as well, |
5010 | * so the return value not includes other pending runtime that other |
5011 | * running tasks might have. |
5012 | */ |
5013 | unsigned long long thread_group_sched_runtime(struct task_struct *p) |
5014 | { |
5015 | struct task_cputime totals; |
5016 | unsigned long flags; |
5017 | struct rq *rq; |
5018 | u64 ns; |
5019 | |
5020 | rq = task_rq_lock(p, &flags); |
5021 | thread_group_cputime(p, &totals); |
5022 | ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq); |
5023 | task_rq_unlock(rq, &flags); |
5024 | |
5025 | return ns; |
5026 | } |
5027 | |
5028 | /* |
5029 | * Account user cpu time to a process. |
5030 | * @p: the process that the cpu time gets accounted to |
5031 | * @cputime: the cpu time spent in user space since the last update |
5032 | * @cputime_scaled: cputime scaled by cpu frequency |
5033 | */ |
5034 | void account_user_time(struct task_struct *p, cputime_t cputime, |
5035 | cputime_t cputime_scaled) |
5036 | { |
5037 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
5038 | cputime64_t tmp; |
5039 | |
5040 | /* Add user time to process. */ |
5041 | p->utime = cputime_add(p->utime, cputime); |
5042 | p->utimescaled = cputime_add(p->utimescaled, cputime_scaled); |
5043 | account_group_user_time(p, cputime); |
5044 | |
5045 | /* Add user time to cpustat. */ |
5046 | tmp = cputime_to_cputime64(cputime); |
5047 | if (TASK_NICE(p) > 0) |
5048 | cpustat->nice = cputime64_add(cpustat->nice, tmp); |
5049 | else |
5050 | cpustat->user = cputime64_add(cpustat->user, tmp); |
5051 | |
5052 | cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime); |
5053 | /* Account for user time used */ |
5054 | acct_update_integrals(p); |
5055 | } |
5056 | |
5057 | /* |
5058 | * Account guest cpu time to a process. |
5059 | * @p: the process that the cpu time gets accounted to |
5060 | * @cputime: the cpu time spent in virtual machine since the last update |
5061 | * @cputime_scaled: cputime scaled by cpu frequency |
5062 | */ |
5063 | static void account_guest_time(struct task_struct *p, cputime_t cputime, |
5064 | cputime_t cputime_scaled) |
5065 | { |
5066 | cputime64_t tmp; |
5067 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
5068 | |
5069 | tmp = cputime_to_cputime64(cputime); |
5070 | |
5071 | /* Add guest time to process. */ |
5072 | p->utime = cputime_add(p->utime, cputime); |
5073 | p->utimescaled = cputime_add(p->utimescaled, cputime_scaled); |
5074 | account_group_user_time(p, cputime); |
5075 | p->gtime = cputime_add(p->gtime, cputime); |
5076 | |
5077 | /* Add guest time to cpustat. */ |
5078 | cpustat->user = cputime64_add(cpustat->user, tmp); |
5079 | cpustat->guest = cputime64_add(cpustat->guest, tmp); |
5080 | } |
5081 | |
5082 | /* |
5083 | * Account system cpu time to a process. |
5084 | * @p: the process that the cpu time gets accounted to |
5085 | * @hardirq_offset: the offset to subtract from hardirq_count() |
5086 | * @cputime: the cpu time spent in kernel space since the last update |
5087 | * @cputime_scaled: cputime scaled by cpu frequency |
5088 | */ |
5089 | void account_system_time(struct task_struct *p, int hardirq_offset, |
5090 | cputime_t cputime, cputime_t cputime_scaled) |
5091 | { |
5092 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
5093 | cputime64_t tmp; |
5094 | |
5095 | if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { |
5096 | account_guest_time(p, cputime, cputime_scaled); |
5097 | return; |
5098 | } |
5099 | |
5100 | /* Add system time to process. */ |
5101 | p->stime = cputime_add(p->stime, cputime); |
5102 | p->stimescaled = cputime_add(p->stimescaled, cputime_scaled); |
5103 | account_group_system_time(p, cputime); |
5104 | |
5105 | /* Add system time to cpustat. */ |
5106 | tmp = cputime_to_cputime64(cputime); |
5107 | if (hardirq_count() - hardirq_offset) |
5108 | cpustat->irq = cputime64_add(cpustat->irq, tmp); |
5109 | else if (softirq_count()) |
5110 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); |
5111 | else |
5112 | cpustat->system = cputime64_add(cpustat->system, tmp); |
5113 | |
5114 | cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime); |
5115 | |
5116 | /* Account for system time used */ |
5117 | acct_update_integrals(p); |
5118 | } |
5119 | |
5120 | /* |
5121 | * Account for involuntary wait time. |
5122 | * @steal: the cpu time spent in involuntary wait |
5123 | */ |
5124 | void account_steal_time(cputime_t cputime) |
5125 | { |
5126 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
5127 | cputime64_t cputime64 = cputime_to_cputime64(cputime); |
5128 | |
5129 | cpustat->steal = cputime64_add(cpustat->steal, cputime64); |
5130 | } |
5131 | |
5132 | /* |
5133 | * Account for idle time. |
5134 | * @cputime: the cpu time spent in idle wait |
5135 | */ |
5136 | void account_idle_time(cputime_t cputime) |
5137 | { |
5138 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
5139 | cputime64_t cputime64 = cputime_to_cputime64(cputime); |
5140 | struct rq *rq = this_rq(); |
5141 | |
5142 | if (atomic_read(&rq->nr_iowait) > 0) |
5143 | cpustat->iowait = cputime64_add(cpustat->iowait, cputime64); |
5144 | else |
5145 | cpustat->idle = cputime64_add(cpustat->idle, cputime64); |
5146 | } |
5147 | |
5148 | #ifndef CONFIG_VIRT_CPU_ACCOUNTING |
5149 | |
5150 | /* |
5151 | * Account a single tick of cpu time. |
5152 | * @p: the process that the cpu time gets accounted to |
5153 | * @user_tick: indicates if the tick is a user or a system tick |
5154 | */ |
5155 | void account_process_tick(struct task_struct *p, int user_tick) |
5156 | { |
5157 | cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); |
5158 | struct rq *rq = this_rq(); |
5159 | |
5160 | if (user_tick) |
5161 | account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); |
5162 | else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) |
5163 | account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, |
5164 | one_jiffy_scaled); |
5165 | else |
5166 | account_idle_time(cputime_one_jiffy); |
5167 | } |
5168 | |
5169 | /* |
5170 | * Account multiple ticks of steal time. |
5171 | * @p: the process from which the cpu time has been stolen |
5172 | * @ticks: number of stolen ticks |
5173 | */ |
5174 | void account_steal_ticks(unsigned long ticks) |
5175 | { |
5176 | account_steal_time(jiffies_to_cputime(ticks)); |
5177 | } |
5178 | |
5179 | /* |
5180 | * Account multiple ticks of idle time. |
5181 | * @ticks: number of stolen ticks |
5182 | */ |
5183 | void account_idle_ticks(unsigned long ticks) |
5184 | { |
5185 | account_idle_time(jiffies_to_cputime(ticks)); |
5186 | } |
5187 | |
5188 | #endif |
5189 | |
5190 | /* |
5191 | * Use precise platform statistics if available: |
5192 | */ |
5193 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING |
5194 | cputime_t task_utime(struct task_struct *p) |
5195 | { |
5196 | return p->utime; |
5197 | } |
5198 | |
5199 | cputime_t task_stime(struct task_struct *p) |
5200 | { |
5201 | return p->stime; |
5202 | } |
5203 | #else |
5204 | cputime_t task_utime(struct task_struct *p) |
5205 | { |
5206 | clock_t utime = cputime_to_clock_t(p->utime), |
5207 | total = utime + cputime_to_clock_t(p->stime); |
5208 | u64 temp; |
5209 | |
5210 | /* |
5211 | * Use CFS's precise accounting: |
5212 | */ |
5213 | temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime); |
5214 | |
5215 | if (total) { |
5216 | temp *= utime; |
5217 | do_div(temp, total); |
5218 | } |
5219 | utime = (clock_t)temp; |
5220 | |
5221 | p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime)); |
5222 | return p->prev_utime; |
5223 | } |
5224 | |
5225 | cputime_t task_stime(struct task_struct *p) |
5226 | { |
5227 | clock_t stime; |
5228 | |
5229 | /* |
5230 | * Use CFS's precise accounting. (we subtract utime from |
5231 | * the total, to make sure the total observed by userspace |
5232 | * grows monotonically - apps rely on that): |
5233 | */ |
5234 | stime = nsec_to_clock_t(p->se.sum_exec_runtime) - |
5235 | cputime_to_clock_t(task_utime(p)); |
5236 | |
5237 | if (stime >= 0) |
5238 | p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime)); |
5239 | |
5240 | return p->prev_stime; |
5241 | } |
5242 | #endif |
5243 | |
5244 | inline cputime_t task_gtime(struct task_struct *p) |
5245 | { |
5246 | return p->gtime; |
5247 | } |
5248 | |
5249 | /* |
5250 | * This function gets called by the timer code, with HZ frequency. |
5251 | * We call it with interrupts disabled. |
5252 | * |
5253 | * It also gets called by the fork code, when changing the parent's |
5254 | * timeslices. |
5255 | */ |
5256 | void scheduler_tick(void) |
5257 | { |
5258 | int cpu = smp_processor_id(); |
5259 | struct rq *rq = cpu_rq(cpu); |
5260 | struct task_struct *curr = rq->curr; |
5261 | |
5262 | sched_clock_tick(); |
5263 | |
5264 | spin_lock(&rq->lock); |
5265 | update_rq_clock(rq); |
5266 | update_cpu_load(rq); |
5267 | curr->sched_class->task_tick(rq, curr, 0); |
5268 | spin_unlock(&rq->lock); |
5269 | |
5270 | perf_event_task_tick(curr, cpu); |
5271 | |
5272 | #ifdef CONFIG_SMP |
5273 | rq->idle_at_tick = idle_cpu(cpu); |
5274 | trigger_load_balance(rq, cpu); |
5275 | #endif |
5276 | } |
5277 | |
5278 | notrace unsigned long get_parent_ip(unsigned long addr) |
5279 | { |
5280 | if (in_lock_functions(addr)) { |
5281 | addr = CALLER_ADDR2; |
5282 | if (in_lock_functions(addr)) |
5283 | addr = CALLER_ADDR3; |
5284 | } |
5285 | return addr; |
5286 | } |
5287 | |
5288 | #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ |
5289 | defined(CONFIG_PREEMPT_TRACER)) |
5290 | |
5291 | void __kprobes add_preempt_count(int val) |
5292 | { |
5293 | #ifdef CONFIG_DEBUG_PREEMPT |
5294 | /* |
5295 | * Underflow? |
5296 | */ |
5297 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
5298 | return; |
5299 | #endif |
5300 | preempt_count() += val; |
5301 | #ifdef CONFIG_DEBUG_PREEMPT |
5302 | /* |
5303 | * Spinlock count overflowing soon? |
5304 | */ |
5305 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
5306 | PREEMPT_MASK - 10); |
5307 | #endif |
5308 | if (preempt_count() == val) |
5309 | trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); |
5310 | } |
5311 | EXPORT_SYMBOL(add_preempt_count); |
5312 | |
5313 | void __kprobes sub_preempt_count(int val) |
5314 | { |
5315 | #ifdef CONFIG_DEBUG_PREEMPT |
5316 | /* |
5317 | * Underflow? |
5318 | */ |
5319 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
5320 | return; |
5321 | /* |
5322 | * Is the spinlock portion underflowing? |
5323 | */ |
5324 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
5325 | !(preempt_count() & PREEMPT_MASK))) |
5326 | return; |
5327 | #endif |
5328 | |
5329 | if (preempt_count() == val) |
5330 | trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); |
5331 | preempt_count() -= val; |
5332 | } |
5333 | EXPORT_SYMBOL(sub_preempt_count); |
5334 | |
5335 | #endif |
5336 | |
5337 | /* |
5338 | * Print scheduling while atomic bug: |
5339 | */ |
5340 | static noinline void __schedule_bug(struct task_struct *prev) |
5341 | { |
5342 | struct pt_regs *regs = get_irq_regs(); |
5343 | |
5344 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", |
5345 | prev->comm, prev->pid, preempt_count()); |
5346 | |
5347 | debug_show_held_locks(prev); |
5348 | print_modules(); |
5349 | if (irqs_disabled()) |
5350 | print_irqtrace_events(prev); |
5351 | |
5352 | if (regs) |
5353 | show_regs(regs); |
5354 | else |
5355 | dump_stack(); |
5356 | } |
5357 | |
5358 | /* |
5359 | * Various schedule()-time debugging checks and statistics: |
5360 | */ |
5361 | static inline void schedule_debug(struct task_struct *prev) |
5362 | { |
5363 | /* |
5364 | * Test if we are atomic. Since do_exit() needs to call into |
5365 | * schedule() atomically, we ignore that path for now. |
5366 | * Otherwise, whine if we are scheduling when we should not be. |
5367 | */ |
5368 | if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) |
5369 | __schedule_bug(prev); |
5370 | |
5371 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
5372 | |
5373 | schedstat_inc(this_rq(), sched_count); |
5374 | #ifdef CONFIG_SCHEDSTATS |
5375 | if (unlikely(prev->lock_depth >= 0)) { |
5376 | schedstat_inc(this_rq(), bkl_count); |
5377 | schedstat_inc(prev, sched_info.bkl_count); |
5378 | } |
5379 | #endif |
5380 | } |
5381 | |
5382 | static void put_prev_task(struct rq *rq, struct task_struct *p) |
5383 | { |
5384 | u64 runtime = p->se.sum_exec_runtime - p->se.prev_sum_exec_runtime; |
5385 | |
5386 | update_avg(&p->se.avg_running, runtime); |
5387 | |
5388 | if (p->state == TASK_RUNNING) { |
5389 | /* |
5390 | * In order to avoid avg_overlap growing stale when we are |
5391 | * indeed overlapping and hence not getting put to sleep, grow |
5392 | * the avg_overlap on preemption. |
5393 | * |
5394 | * We use the average preemption runtime because that |
5395 | * correlates to the amount of cache footprint a task can |
5396 | * build up. |
5397 | */ |
5398 | runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost); |
5399 | update_avg(&p->se.avg_overlap, runtime); |
5400 | } else { |
5401 | update_avg(&p->se.avg_running, 0); |
5402 | } |
5403 | p->sched_class->put_prev_task(rq, p); |
5404 | } |
5405 | |
5406 | /* |
5407 | * Pick up the highest-prio task: |
5408 | */ |
5409 | static inline struct task_struct * |
5410 | pick_next_task(struct rq *rq) |
5411 | { |
5412 | const struct sched_class *class; |
5413 | struct task_struct *p; |
5414 | |
5415 | /* |
5416 | * Optimization: we know that if all tasks are in |
5417 | * the fair class we can call that function directly: |
5418 | */ |
5419 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
5420 | p = fair_sched_class.pick_next_task(rq); |
5421 | if (likely(p)) |
5422 | return p; |
5423 | } |
5424 | |
5425 | class = sched_class_highest; |
5426 | for ( ; ; ) { |
5427 | p = class->pick_next_task(rq); |
5428 | if (p) |
5429 | return p; |
5430 | /* |
5431 | * Will never be NULL as the idle class always |
5432 | * returns a non-NULL p: |
5433 | */ |
5434 | class = class->next; |
5435 | } |
5436 | } |
5437 | |
5438 | /* |
5439 | * schedule() is the main scheduler function. |
5440 | */ |
5441 | asmlinkage void __sched schedule(void) |
5442 | { |
5443 | struct task_struct *prev, *next; |
5444 | unsigned long *switch_count; |
5445 | struct rq *rq; |
5446 | int cpu; |
5447 | |
5448 | need_resched: |
5449 | preempt_disable(); |
5450 | cpu = smp_processor_id(); |
5451 | rq = cpu_rq(cpu); |
5452 | rcu_sched_qs(cpu); |
5453 | prev = rq->curr; |
5454 | switch_count = &prev->nivcsw; |
5455 | |
5456 | release_kernel_lock(prev); |
5457 | need_resched_nonpreemptible: |
5458 | |
5459 | schedule_debug(prev); |
5460 | |
5461 | if (sched_feat(HRTICK)) |
5462 | hrtick_clear(rq); |
5463 | |
5464 | spin_lock_irq(&rq->lock); |
5465 | update_rq_clock(rq); |
5466 | clear_tsk_need_resched(prev); |
5467 | |
5468 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
5469 | if (unlikely(signal_pending_state(prev->state, prev))) |
5470 | prev->state = TASK_RUNNING; |
5471 | else |
5472 | deactivate_task(rq, prev, 1); |
5473 | switch_count = &prev->nvcsw; |
5474 | } |
5475 | |
5476 | pre_schedule(rq, prev); |
5477 | |
5478 | if (unlikely(!rq->nr_running)) |
5479 | idle_balance(cpu, rq); |
5480 | |
5481 | put_prev_task(rq, prev); |
5482 | next = pick_next_task(rq); |
5483 | |
5484 | if (likely(prev != next)) { |
5485 | sched_info_switch(prev, next); |
5486 | perf_event_task_sched_out(prev, next, cpu); |
5487 | |
5488 | rq->nr_switches++; |
5489 | rq->curr = next; |
5490 | ++*switch_count; |
5491 | |
5492 | context_switch(rq, prev, next); /* unlocks the rq */ |
5493 | /* |
5494 | * the context switch might have flipped the stack from under |
5495 | * us, hence refresh the local variables. |
5496 | */ |
5497 | cpu = smp_processor_id(); |
5498 | rq = cpu_rq(cpu); |
5499 | } else |
5500 | spin_unlock_irq(&rq->lock); |
5501 | |
5502 | post_schedule(rq); |
5503 | |
5504 | if (unlikely(reacquire_kernel_lock(current) < 0)) |
5505 | goto need_resched_nonpreemptible; |
5506 | |
5507 | preempt_enable_no_resched(); |
5508 | if (need_resched()) |
5509 | goto need_resched; |
5510 | } |
5511 | EXPORT_SYMBOL(schedule); |
5512 | |
5513 | #ifdef CONFIG_SMP |
5514 | /* |
5515 | * Look out! "owner" is an entirely speculative pointer |
5516 | * access and not reliable. |
5517 | */ |
5518 | int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner) |
5519 | { |
5520 | unsigned int cpu; |
5521 | struct rq *rq; |
5522 | |
5523 | if (!sched_feat(OWNER_SPIN)) |
5524 | return 0; |
5525 | |
5526 | #ifdef CONFIG_DEBUG_PAGEALLOC |
5527 | /* |
5528 | * Need to access the cpu field knowing that |
5529 | * DEBUG_PAGEALLOC could have unmapped it if |
5530 | * the mutex owner just released it and exited. |
5531 | */ |
5532 | if (probe_kernel_address(&owner->cpu, cpu)) |
5533 | goto out; |
5534 | #else |
5535 | cpu = owner->cpu; |
5536 | #endif |
5537 | |
5538 | /* |
5539 | * Even if the access succeeded (likely case), |
5540 | * the cpu field may no longer be valid. |
5541 | */ |
5542 | if (cpu >= nr_cpumask_bits) |
5543 | goto out; |
5544 | |
5545 | /* |
5546 | * We need to validate that we can do a |
5547 | * get_cpu() and that we have the percpu area. |
5548 | */ |
5549 | if (!cpu_online(cpu)) |
5550 | goto out; |
5551 | |
5552 | rq = cpu_rq(cpu); |
5553 | |
5554 | for (;;) { |
5555 | /* |
5556 | * Owner changed, break to re-assess state. |
5557 | */ |
5558 | if (lock->owner != owner) |
5559 | break; |
5560 | |
5561 | /* |
5562 | * Is that owner really running on that cpu? |
5563 | */ |
5564 | if (task_thread_info(rq->curr) != owner || need_resched()) |
5565 | return 0; |
5566 | |
5567 | cpu_relax(); |
5568 | } |
5569 | out: |
5570 | return 1; |
5571 | } |
5572 | #endif |
5573 | |
5574 | #ifdef CONFIG_PREEMPT |
5575 | /* |
5576 | * this is the entry point to schedule() from in-kernel preemption |
5577 | * off of preempt_enable. Kernel preemptions off return from interrupt |
5578 | * occur there and call schedule directly. |
5579 | */ |
5580 | asmlinkage void __sched preempt_schedule(void) |
5581 | { |
5582 | struct thread_info *ti = current_thread_info(); |
5583 | |
5584 | /* |
5585 | * If there is a non-zero preempt_count or interrupts are disabled, |
5586 | * we do not want to preempt the current task. Just return.. |
5587 | */ |
5588 | if (likely(ti->preempt_count || irqs_disabled())) |
5589 | return; |
5590 | |
5591 | do { |
5592 | add_preempt_count(PREEMPT_ACTIVE); |
5593 | schedule(); |
5594 | sub_preempt_count(PREEMPT_ACTIVE); |
5595 | |
5596 | /* |
5597 | * Check again in case we missed a preemption opportunity |
5598 | * between schedule and now. |
5599 | */ |
5600 | barrier(); |
5601 | } while (need_resched()); |
5602 | } |
5603 | EXPORT_SYMBOL(preempt_schedule); |
5604 | |
5605 | /* |
5606 | * this is the entry point to schedule() from kernel preemption |
5607 | * off of irq context. |
5608 | * Note, that this is called and return with irqs disabled. This will |
5609 | * protect us against recursive calling from irq. |
5610 | */ |
5611 | asmlinkage void __sched preempt_schedule_irq(void) |
5612 | { |
5613 | struct thread_info *ti = current_thread_info(); |
5614 | |
5615 | /* Catch callers which need to be fixed */ |
5616 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
5617 | |
5618 | do { |
5619 | add_preempt_count(PREEMPT_ACTIVE); |
5620 | local_irq_enable(); |
5621 | schedule(); |
5622 | local_irq_disable(); |
5623 | sub_preempt_count(PREEMPT_ACTIVE); |
5624 | |
5625 | /* |
5626 | * Check again in case we missed a preemption opportunity |
5627 | * between schedule and now. |
5628 | */ |
5629 | barrier(); |
5630 | } while (need_resched()); |
5631 | } |
5632 | |
5633 | #endif /* CONFIG_PREEMPT */ |
5634 | |
5635 | int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, |
5636 | void *key) |
5637 | { |
5638 | return try_to_wake_up(curr->private, mode, wake_flags); |
5639 | } |
5640 | EXPORT_SYMBOL(default_wake_function); |
5641 | |
5642 | /* |
5643 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
5644 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve |
5645 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
5646 | * |
5647 | * There are circumstances in which we can try to wake a task which has already |
5648 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
5649 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
5650 | */ |
5651 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, |
5652 | int nr_exclusive, int wake_flags, void *key) |
5653 | { |
5654 | wait_queue_t *curr, *next; |
5655 | |
5656 | list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
5657 | unsigned flags = curr->flags; |
5658 | |
5659 | if (curr->func(curr, mode, wake_flags, key) && |
5660 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
5661 | break; |
5662 | } |
5663 | } |
5664 | |
5665 | /** |
5666 | * __wake_up - wake up threads blocked on a waitqueue. |
5667 | * @q: the waitqueue |
5668 | * @mode: which threads |
5669 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
5670 | * @key: is directly passed to the wakeup function |
5671 | * |
5672 | * It may be assumed that this function implies a write memory barrier before |
5673 | * changing the task state if and only if any tasks are woken up. |
5674 | */ |
5675 | void __wake_up(wait_queue_head_t *q, unsigned int mode, |
5676 | int nr_exclusive, void *key) |
5677 | { |
5678 | unsigned long flags; |
5679 | |
5680 | spin_lock_irqsave(&q->lock, flags); |
5681 | __wake_up_common(q, mode, nr_exclusive, 0, key); |
5682 | spin_unlock_irqrestore(&q->lock, flags); |
5683 | } |
5684 | EXPORT_SYMBOL(__wake_up); |
5685 | |
5686 | /* |
5687 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. |
5688 | */ |
5689 | void __wake_up_locked(wait_queue_head_t *q, unsigned int mode) |
5690 | { |
5691 | __wake_up_common(q, mode, 1, 0, NULL); |
5692 | } |
5693 | |
5694 | void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) |
5695 | { |
5696 | __wake_up_common(q, mode, 1, 0, key); |
5697 | } |
5698 | |
5699 | /** |
5700 | * __wake_up_sync_key - wake up threads blocked on a waitqueue. |
5701 | * @q: the waitqueue |
5702 | * @mode: which threads |
5703 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
5704 | * @key: opaque value to be passed to wakeup targets |
5705 | * |
5706 | * The sync wakeup differs that the waker knows that it will schedule |
5707 | * away soon, so while the target thread will be woken up, it will not |
5708 | * be migrated to another CPU - ie. the two threads are 'synchronized' |
5709 | * with each other. This can prevent needless bouncing between CPUs. |
5710 | * |
5711 | * On UP it can prevent extra preemption. |
5712 | * |
5713 | * It may be assumed that this function implies a write memory barrier before |
5714 | * changing the task state if and only if any tasks are woken up. |
5715 | */ |
5716 | void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, |
5717 | int nr_exclusive, void *key) |
5718 | { |
5719 | unsigned long flags; |
5720 | int wake_flags = WF_SYNC; |
5721 | |
5722 | if (unlikely(!q)) |
5723 | return; |
5724 | |
5725 | if (unlikely(!nr_exclusive)) |
5726 | wake_flags = 0; |
5727 | |
5728 | spin_lock_irqsave(&q->lock, flags); |
5729 | __wake_up_common(q, mode, nr_exclusive, wake_flags, key); |
5730 | spin_unlock_irqrestore(&q->lock, flags); |
5731 | } |
5732 | EXPORT_SYMBOL_GPL(__wake_up_sync_key); |
5733 | |
5734 | /* |
5735 | * __wake_up_sync - see __wake_up_sync_key() |
5736 | */ |
5737 | void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) |
5738 | { |
5739 | __wake_up_sync_key(q, mode, nr_exclusive, NULL); |
5740 | } |
5741 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ |
5742 | |
5743 | /** |
5744 | * complete: - signals a single thread waiting on this completion |
5745 | * @x: holds the state of this particular completion |
5746 | * |
5747 | * This will wake up a single thread waiting on this completion. Threads will be |
5748 | * awakened in the same order in which they were queued. |
5749 | * |
5750 | * See also complete_all(), wait_for_completion() and related routines. |
5751 | * |
5752 | * It may be assumed that this function implies a write memory barrier before |
5753 | * changing the task state if and only if any tasks are woken up. |
5754 | */ |
5755 | void complete(struct completion *x) |
5756 | { |
5757 | unsigned long flags; |
5758 | |
5759 | spin_lock_irqsave(&x->wait.lock, flags); |
5760 | x->done++; |
5761 | __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); |
5762 | spin_unlock_irqrestore(&x->wait.lock, flags); |
5763 | } |
5764 | EXPORT_SYMBOL(complete); |
5765 | |
5766 | /** |
5767 | * complete_all: - signals all threads waiting on this completion |
5768 | * @x: holds the state of this particular completion |
5769 | * |
5770 | * This will wake up all threads waiting on this particular completion event. |
5771 | * |
5772 | * It may be assumed that this function implies a write memory barrier before |
5773 | * changing the task state if and only if any tasks are woken up. |
5774 | */ |
5775 | void complete_all(struct completion *x) |
5776 | { |
5777 | unsigned long flags; |
5778 | |
5779 | spin_lock_irqsave(&x->wait.lock, flags); |
5780 | x->done += UINT_MAX/2; |
5781 | __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); |
5782 | spin_unlock_irqrestore(&x->wait.lock, flags); |
5783 | } |
5784 | EXPORT_SYMBOL(complete_all); |
5785 | |
5786 | static inline long __sched |
5787 | do_wait_for_common(struct completion *x, long timeout, int state) |
5788 | { |
5789 | if (!x->done) { |
5790 | DECLARE_WAITQUEUE(wait, current); |
5791 | |
5792 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
5793 | __add_wait_queue_tail(&x->wait, &wait); |
5794 | do { |
5795 | if (signal_pending_state(state, current)) { |
5796 | timeout = -ERESTARTSYS; |
5797 | break; |
5798 | } |
5799 | __set_current_state(state); |
5800 | spin_unlock_irq(&x->wait.lock); |
5801 | timeout = schedule_timeout(timeout); |
5802 | spin_lock_irq(&x->wait.lock); |
5803 | } while (!x->done && timeout); |
5804 | __remove_wait_queue(&x->wait, &wait); |
5805 | if (!x->done) |
5806 | return timeout; |
5807 | } |
5808 | x->done--; |
5809 | return timeout ?: 1; |
5810 | } |
5811 | |
5812 | static long __sched |
5813 | wait_for_common(struct completion *x, long timeout, int state) |
5814 | { |
5815 | might_sleep(); |
5816 | |
5817 | spin_lock_irq(&x->wait.lock); |
5818 | timeout = do_wait_for_common(x, timeout, state); |
5819 | spin_unlock_irq(&x->wait.lock); |
5820 | return timeout; |
5821 | } |
5822 | |
5823 | /** |
5824 | * wait_for_completion: - waits for completion of a task |
5825 | * @x: holds the state of this particular completion |
5826 | * |
5827 | * This waits to be signaled for completion of a specific task. It is NOT |
5828 | * interruptible and there is no timeout. |
5829 | * |
5830 | * See also similar routines (i.e. wait_for_completion_timeout()) with timeout |
5831 | * and interrupt capability. Also see complete(). |
5832 | */ |
5833 | void __sched wait_for_completion(struct completion *x) |
5834 | { |
5835 | wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); |
5836 | } |
5837 | EXPORT_SYMBOL(wait_for_completion); |
5838 | |
5839 | /** |
5840 | * wait_for_completion_timeout: - waits for completion of a task (w/timeout) |
5841 | * @x: holds the state of this particular completion |
5842 | * @timeout: timeout value in jiffies |
5843 | * |
5844 | * This waits for either a completion of a specific task to be signaled or for a |
5845 | * specified timeout to expire. The timeout is in jiffies. It is not |
5846 | * interruptible. |
5847 | */ |
5848 | unsigned long __sched |
5849 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
5850 | { |
5851 | return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
5852 | } |
5853 | EXPORT_SYMBOL(wait_for_completion_timeout); |
5854 | |
5855 | /** |
5856 | * wait_for_completion_interruptible: - waits for completion of a task (w/intr) |
5857 | * @x: holds the state of this particular completion |
5858 | * |
5859 | * This waits for completion of a specific task to be signaled. It is |
5860 | * interruptible. |
5861 | */ |
5862 | int __sched wait_for_completion_interruptible(struct completion *x) |
5863 | { |
5864 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
5865 | if (t == -ERESTARTSYS) |
5866 | return t; |
5867 | return 0; |
5868 | } |
5869 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
5870 | |
5871 | /** |
5872 | * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) |
5873 | * @x: holds the state of this particular completion |
5874 | * @timeout: timeout value in jiffies |
5875 | * |
5876 | * This waits for either a completion of a specific task to be signaled or for a |
5877 | * specified timeout to expire. It is interruptible. The timeout is in jiffies. |
5878 | */ |
5879 | unsigned long __sched |
5880 | wait_for_completion_interruptible_timeout(struct completion *x, |
5881 | unsigned long timeout) |
5882 | { |
5883 | return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
5884 | } |
5885 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
5886 | |
5887 | /** |
5888 | * wait_for_completion_killable: - waits for completion of a task (killable) |
5889 | * @x: holds the state of this particular completion |
5890 | * |
5891 | * This waits to be signaled for completion of a specific task. It can be |
5892 | * interrupted by a kill signal. |
5893 | */ |
5894 | int __sched wait_for_completion_killable(struct completion *x) |
5895 | { |
5896 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); |
5897 | if (t == -ERESTARTSYS) |
5898 | return t; |
5899 | return 0; |
5900 | } |
5901 | EXPORT_SYMBOL(wait_for_completion_killable); |
5902 | |
5903 | /** |
5904 | * try_wait_for_completion - try to decrement a completion without blocking |
5905 | * @x: completion structure |
5906 | * |
5907 | * Returns: 0 if a decrement cannot be done without blocking |
5908 | * 1 if a decrement succeeded. |
5909 | * |
5910 | * If a completion is being used as a counting completion, |
5911 | * attempt to decrement the counter without blocking. This |
5912 | * enables us to avoid waiting if the resource the completion |
5913 | * is protecting is not available. |
5914 | */ |
5915 | bool try_wait_for_completion(struct completion *x) |
5916 | { |
5917 | int ret = 1; |
5918 | |
5919 | spin_lock_irq(&x->wait.lock); |
5920 | if (!x->done) |
5921 | ret = 0; |
5922 | else |
5923 | x->done--; |
5924 | spin_unlock_irq(&x->wait.lock); |
5925 | return ret; |
5926 | } |
5927 | EXPORT_SYMBOL(try_wait_for_completion); |
5928 | |
5929 | /** |
5930 | * completion_done - Test to see if a completion has any waiters |
5931 | * @x: completion structure |
5932 | * |
5933 | * Returns: 0 if there are waiters (wait_for_completion() in progress) |
5934 | * 1 if there are no waiters. |
5935 | * |
5936 | */ |
5937 | bool completion_done(struct completion *x) |
5938 | { |
5939 | int ret = 1; |
5940 | |
5941 | spin_lock_irq(&x->wait.lock); |
5942 | if (!x->done) |
5943 | ret = 0; |
5944 | spin_unlock_irq(&x->wait.lock); |
5945 | return ret; |
5946 | } |
5947 | EXPORT_SYMBOL(completion_done); |
5948 | |
5949 | static long __sched |
5950 | sleep_on_common(wait_queue_head_t *q, int state, long timeout) |
5951 | { |
5952 | unsigned long flags; |
5953 | wait_queue_t wait; |
5954 | |
5955 | init_waitqueue_entry(&wait, current); |
5956 | |
5957 | __set_current_state(state); |
5958 | |
5959 | spin_lock_irqsave(&q->lock, flags); |
5960 | __add_wait_queue(q, &wait); |
5961 | spin_unlock(&q->lock); |
5962 | timeout = schedule_timeout(timeout); |
5963 | spin_lock_irq(&q->lock); |
5964 | __remove_wait_queue(q, &wait); |
5965 | spin_unlock_irqrestore(&q->lock, flags); |
5966 | |
5967 | return timeout; |
5968 | } |
5969 | |
5970 | void __sched interruptible_sleep_on(wait_queue_head_t *q) |
5971 | { |
5972 | sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
5973 | } |
5974 | EXPORT_SYMBOL(interruptible_sleep_on); |
5975 | |
5976 | long __sched |
5977 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
5978 | { |
5979 | return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
5980 | } |
5981 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
5982 | |
5983 | void __sched sleep_on(wait_queue_head_t *q) |
5984 | { |
5985 | sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
5986 | } |
5987 | EXPORT_SYMBOL(sleep_on); |
5988 | |
5989 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
5990 | { |
5991 | return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
5992 | } |
5993 | EXPORT_SYMBOL(sleep_on_timeout); |
5994 | |
5995 | #ifdef CONFIG_RT_MUTEXES |
5996 | |
5997 | /* |
5998 | * rt_mutex_setprio - set the current priority of a task |
5999 | * @p: task |
6000 | * @prio: prio value (kernel-internal form) |
6001 | * |
6002 | * This function changes the 'effective' priority of a task. It does |
6003 | * not touch ->normal_prio like __setscheduler(). |
6004 | * |
6005 | * Used by the rt_mutex code to implement priority inheritance logic. |
6006 | */ |
6007 | void rt_mutex_setprio(struct task_struct *p, int prio) |
6008 | { |
6009 | unsigned long flags; |
6010 | int oldprio, on_rq, running; |
6011 | struct rq *rq; |
6012 | const struct sched_class *prev_class; |
6013 | |
6014 | BUG_ON(prio < 0 || prio > MAX_PRIO); |
6015 | |
6016 | rq = task_rq_lock(p, &flags); |
6017 | update_rq_clock(rq); |
6018 | |
6019 | oldprio = p->prio; |
6020 | prev_class = p->sched_class; |
6021 | on_rq = p->se.on_rq; |
6022 | running = task_current(rq, p); |
6023 | if (on_rq) |
6024 | dequeue_task(rq, p, 0); |
6025 | if (running) |
6026 | p->sched_class->put_prev_task(rq, p); |
6027 | |
6028 | if (rt_prio(prio)) |
6029 | p->sched_class = &rt_sched_class; |
6030 | else |
6031 | p->sched_class = &fair_sched_class; |
6032 | |
6033 | p->prio = prio; |
6034 | |
6035 | if (running) |
6036 | p->sched_class->set_curr_task(rq); |
6037 | if (on_rq) { |
6038 | enqueue_task(rq, p, 0); |
6039 | |
6040 | check_class_changed(rq, p, prev_class, oldprio, running); |
6041 | } |
6042 | task_rq_unlock(rq, &flags); |
6043 | } |
6044 | |
6045 | #endif |
6046 | |
6047 | void set_user_nice(struct task_struct *p, long nice) |
6048 | { |
6049 | int old_prio, delta, on_rq; |
6050 | unsigned long flags; |
6051 | struct rq *rq; |
6052 | |
6053 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) |
6054 | return; |
6055 | /* |
6056 | * We have to be careful, if called from sys_setpriority(), |
6057 | * the task might be in the middle of scheduling on another CPU. |
6058 | */ |
6059 | rq = task_rq_lock(p, &flags); |
6060 | update_rq_clock(rq); |
6061 | /* |
6062 | * The RT priorities are set via sched_setscheduler(), but we still |
6063 | * allow the 'normal' nice value to be set - but as expected |
6064 | * it wont have any effect on scheduling until the task is |
6065 | * SCHED_FIFO/SCHED_RR: |
6066 | */ |
6067 | if (task_has_rt_policy(p)) { |
6068 | p->static_prio = NICE_TO_PRIO(nice); |
6069 | goto out_unlock; |
6070 | } |
6071 | on_rq = p->se.on_rq; |
6072 | if (on_rq) |
6073 | dequeue_task(rq, p, 0); |
6074 | |
6075 | p->static_prio = NICE_TO_PRIO(nice); |
6076 | set_load_weight(p); |
6077 | old_prio = p->prio; |
6078 | p->prio = effective_prio(p); |
6079 | delta = p->prio - old_prio; |
6080 | |
6081 | if (on_rq) { |
6082 | enqueue_task(rq, p, 0); |
6083 | /* |
6084 | * If the task increased its priority or is running and |
6085 | * lowered its priority, then reschedule its CPU: |
6086 | */ |
6087 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
6088 | resched_task(rq->curr); |
6089 | } |
6090 | out_unlock: |
6091 | task_rq_unlock(rq, &flags); |
6092 | } |
6093 | EXPORT_SYMBOL(set_user_nice); |
6094 | |
6095 | /* |
6096 | * can_nice - check if a task can reduce its nice value |
6097 | * @p: task |
6098 | * @nice: nice value |
6099 | */ |
6100 | int can_nice(const struct task_struct *p, const int nice) |
6101 | { |
6102 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
6103 | int nice_rlim = 20 - nice; |
6104 | |
6105 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
6106 | capable(CAP_SYS_NICE)); |
6107 | } |
6108 | EXPORT_SYMBOL_GPL(can_nice); |
6109 | |
6110 | #ifdef __ARCH_WANT_SYS_NICE |
6111 | |
6112 | /* |
6113 | * sys_nice - change the priority of the current process. |
6114 | * @increment: priority increment |
6115 | * |
6116 | * sys_setpriority is a more generic, but much slower function that |
6117 | * does similar things. |
6118 | */ |
6119 | SYSCALL_DEFINE1(nice, int, increment) |
6120 | { |
6121 | long nice, retval; |
6122 | |
6123 | /* |
6124 | * Setpriority might change our priority at the same moment. |
6125 | * We don't have to worry. Conceptually one call occurs first |
6126 | * and we have a single winner. |
6127 | */ |
6128 | if (increment < -40) |
6129 | increment = -40; |
6130 | if (increment > 40) |
6131 | increment = 40; |
6132 | |
6133 | nice = TASK_NICE(current) + increment; |
6134 | if (nice < -20) |
6135 | nice = -20; |
6136 | if (nice > 19) |
6137 | nice = 19; |
6138 | |
6139 | if (increment < 0 && !can_nice(current, nice)) |
6140 | return -EPERM; |
6141 | |
6142 | retval = security_task_setnice(current, nice); |
6143 | if (retval) |
6144 | return retval; |
6145 | |
6146 | set_user_nice(current, nice); |
6147 | return 0; |
6148 | } |
6149 | |
6150 | #endif |
6151 | |
6152 | /** |
6153 | * task_prio - return the priority value of a given task. |
6154 | * @p: the task in question. |
6155 | * |
6156 | * This is the priority value as seen by users in /proc. |
6157 | * RT tasks are offset by -200. Normal tasks are centered |
6158 | * around 0, value goes from -16 to +15. |
6159 | */ |
6160 | int task_prio(const struct task_struct *p) |
6161 | { |
6162 | return p->prio - MAX_RT_PRIO; |
6163 | } |
6164 | |
6165 | /** |
6166 | * task_nice - return the nice value of a given task. |
6167 | * @p: the task in question. |
6168 | */ |
6169 | int task_nice(const struct task_struct *p) |
6170 | { |
6171 | return TASK_NICE(p); |
6172 | } |
6173 | EXPORT_SYMBOL(task_nice); |
6174 | |
6175 | /** |
6176 | * idle_cpu - is a given cpu idle currently? |
6177 | * @cpu: the processor in question. |
6178 | */ |
6179 | int idle_cpu(int cpu) |
6180 | { |
6181 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; |
6182 | } |
6183 | |
6184 | /** |
6185 | * idle_task - return the idle task for a given cpu. |
6186 | * @cpu: the processor in question. |
6187 | */ |
6188 | struct task_struct *idle_task(int cpu) |
6189 | { |
6190 | return cpu_rq(cpu)->idle; |
6191 | } |
6192 | |
6193 | /** |
6194 | * find_process_by_pid - find a process with a matching PID value. |
6195 | * @pid: the pid in question. |
6196 | */ |
6197 | static struct task_struct *find_process_by_pid(pid_t pid) |
6198 | { |
6199 | return pid ? find_task_by_vpid(pid) : current; |
6200 | } |
6201 | |
6202 | /* Actually do priority change: must hold rq lock. */ |
6203 | static void |
6204 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) |
6205 | { |
6206 | BUG_ON(p->se.on_rq); |
6207 | |
6208 | p->policy = policy; |
6209 | switch (p->policy) { |
6210 | case SCHED_NORMAL: |
6211 | case SCHED_BATCH: |
6212 | case SCHED_IDLE: |
6213 | p->sched_class = &fair_sched_class; |
6214 | break; |
6215 | case SCHED_FIFO: |
6216 | case SCHED_RR: |
6217 | p->sched_class = &rt_sched_class; |
6218 | break; |
6219 | } |
6220 | |
6221 | p->rt_priority = prio; |
6222 | p->normal_prio = normal_prio(p); |
6223 | /* we are holding p->pi_lock already */ |
6224 | p->prio = rt_mutex_getprio(p); |
6225 | set_load_weight(p); |
6226 | } |
6227 | |
6228 | /* |
6229 | * check the target process has a UID that matches the current process's |
6230 | */ |
6231 | static bool check_same_owner(struct task_struct *p) |
6232 | { |
6233 | const struct cred *cred = current_cred(), *pcred; |
6234 | bool match; |
6235 | |
6236 | rcu_read_lock(); |
6237 | pcred = __task_cred(p); |
6238 | match = (cred->euid == pcred->euid || |
6239 | cred->euid == pcred->uid); |
6240 | rcu_read_unlock(); |
6241 | return match; |
6242 | } |
6243 | |
6244 | static int __sched_setscheduler(struct task_struct *p, int policy, |
6245 | struct sched_param *param, bool user) |
6246 | { |
6247 | int retval, oldprio, oldpolicy = -1, on_rq, running; |
6248 | unsigned long flags; |
6249 | const struct sched_class *prev_class; |
6250 | struct rq *rq; |
6251 | int reset_on_fork; |
6252 | |
6253 | /* may grab non-irq protected spin_locks */ |
6254 | BUG_ON(in_interrupt()); |
6255 | recheck: |
6256 | /* double check policy once rq lock held */ |
6257 | if (policy < 0) { |
6258 | reset_on_fork = p->sched_reset_on_fork; |
6259 | policy = oldpolicy = p->policy; |
6260 | } else { |
6261 | reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); |
6262 | policy &= ~SCHED_RESET_ON_FORK; |
6263 | |
6264 | if (policy != SCHED_FIFO && policy != SCHED_RR && |
6265 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
6266 | policy != SCHED_IDLE) |
6267 | return -EINVAL; |
6268 | } |
6269 | |
6270 | /* |
6271 | * Valid priorities for SCHED_FIFO and SCHED_RR are |
6272 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
6273 | * SCHED_BATCH and SCHED_IDLE is 0. |
6274 | */ |
6275 | if (param->sched_priority < 0 || |
6276 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
6277 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
6278 | return -EINVAL; |
6279 | if (rt_policy(policy) != (param->sched_priority != 0)) |
6280 | return -EINVAL; |
6281 | |
6282 | /* |
6283 | * Allow unprivileged RT tasks to decrease priority: |
6284 | */ |
6285 | if (user && !capable(CAP_SYS_NICE)) { |
6286 | if (rt_policy(policy)) { |
6287 | unsigned long rlim_rtprio; |
6288 | |
6289 | if (!lock_task_sighand(p, &flags)) |
6290 | return -ESRCH; |
6291 | rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; |
6292 | unlock_task_sighand(p, &flags); |
6293 | |
6294 | /* can't set/change the rt policy */ |
6295 | if (policy != p->policy && !rlim_rtprio) |
6296 | return -EPERM; |
6297 | |
6298 | /* can't increase priority */ |
6299 | if (param->sched_priority > p->rt_priority && |
6300 | param->sched_priority > rlim_rtprio) |
6301 | return -EPERM; |
6302 | } |
6303 | /* |
6304 | * Like positive nice levels, dont allow tasks to |
6305 | * move out of SCHED_IDLE either: |
6306 | */ |
6307 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) |
6308 | return -EPERM; |
6309 | |
6310 | /* can't change other user's priorities */ |
6311 | if (!check_same_owner(p)) |
6312 | return -EPERM; |
6313 | |
6314 | /* Normal users shall not reset the sched_reset_on_fork flag */ |
6315 | if (p->sched_reset_on_fork && !reset_on_fork) |
6316 | return -EPERM; |
6317 | } |
6318 | |
6319 | if (user) { |
6320 | #ifdef CONFIG_RT_GROUP_SCHED |
6321 | /* |
6322 | * Do not allow realtime tasks into groups that have no runtime |
6323 | * assigned. |
6324 | */ |
6325 | if (rt_bandwidth_enabled() && rt_policy(policy) && |
6326 | task_group(p)->rt_bandwidth.rt_runtime == 0) |
6327 | return -EPERM; |
6328 | #endif |
6329 | |
6330 | retval = security_task_setscheduler(p, policy, param); |
6331 | if (retval) |
6332 | return retval; |
6333 | } |
6334 | |
6335 | /* |
6336 | * make sure no PI-waiters arrive (or leave) while we are |
6337 | * changing the priority of the task: |
6338 | */ |
6339 | spin_lock_irqsave(&p->pi_lock, flags); |
6340 | /* |
6341 | * To be able to change p->policy safely, the apropriate |
6342 | * runqueue lock must be held. |
6343 | */ |
6344 | rq = __task_rq_lock(p); |
6345 | /* recheck policy now with rq lock held */ |
6346 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { |
6347 | policy = oldpolicy = -1; |
6348 | __task_rq_unlock(rq); |
6349 | spin_unlock_irqrestore(&p->pi_lock, flags); |
6350 | goto recheck; |
6351 | } |
6352 | update_rq_clock(rq); |
6353 | on_rq = p->se.on_rq; |
6354 | running = task_current(rq, p); |
6355 | if (on_rq) |
6356 | deactivate_task(rq, p, 0); |
6357 | if (running) |
6358 | p->sched_class->put_prev_task(rq, p); |
6359 | |
6360 | p->sched_reset_on_fork = reset_on_fork; |
6361 | |
6362 | oldprio = p->prio; |
6363 | prev_class = p->sched_class; |
6364 | __setscheduler(rq, p, policy, param->sched_priority); |
6365 | |
6366 | if (running) |
6367 | p->sched_class->set_curr_task(rq); |
6368 | if (on_rq) { |
6369 | activate_task(rq, p, 0); |
6370 | |
6371 | check_class_changed(rq, p, prev_class, oldprio, running); |
6372 | } |
6373 | __task_rq_unlock(rq); |
6374 | spin_unlock_irqrestore(&p->pi_lock, flags); |
6375 | |
6376 | rt_mutex_adjust_pi(p); |
6377 | |
6378 | return 0; |
6379 | } |
6380 | |
6381 | /** |
6382 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
6383 | * @p: the task in question. |
6384 | * @policy: new policy. |
6385 | * @param: structure containing the new RT priority. |
6386 | * |
6387 | * NOTE that the task may be already dead. |
6388 | */ |
6389 | int sched_setscheduler(struct task_struct *p, int policy, |
6390 | struct sched_param *param) |
6391 | { |
6392 | return __sched_setscheduler(p, policy, param, true); |
6393 | } |
6394 | EXPORT_SYMBOL_GPL(sched_setscheduler); |
6395 | |
6396 | /** |
6397 | * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. |
6398 | * @p: the task in question. |
6399 | * @policy: new policy. |
6400 | * @param: structure containing the new RT priority. |
6401 | * |
6402 | * Just like sched_setscheduler, only don't bother checking if the |
6403 | * current context has permission. For example, this is needed in |
6404 | * stop_machine(): we create temporary high priority worker threads, |
6405 | * but our caller might not have that capability. |
6406 | */ |
6407 | int sched_setscheduler_nocheck(struct task_struct *p, int policy, |
6408 | struct sched_param *param) |
6409 | { |
6410 | return __sched_setscheduler(p, policy, param, false); |
6411 | } |
6412 | |
6413 | static int |
6414 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) |
6415 | { |
6416 | struct sched_param lparam; |
6417 | struct task_struct *p; |
6418 | int retval; |
6419 | |
6420 | if (!param || pid < 0) |
6421 | return -EINVAL; |
6422 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) |
6423 | return -EFAULT; |
6424 | |
6425 | rcu_read_lock(); |
6426 | retval = -ESRCH; |
6427 | p = find_process_by_pid(pid); |
6428 | if (p != NULL) |
6429 | retval = sched_setscheduler(p, policy, &lparam); |
6430 | rcu_read_unlock(); |
6431 | |
6432 | return retval; |
6433 | } |
6434 | |
6435 | /** |
6436 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority |
6437 | * @pid: the pid in question. |
6438 | * @policy: new policy. |
6439 | * @param: structure containing the new RT priority. |
6440 | */ |
6441 | SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, |
6442 | struct sched_param __user *, param) |
6443 | { |
6444 | /* negative values for policy are not valid */ |
6445 | if (policy < 0) |
6446 | return -EINVAL; |
6447 | |
6448 | return do_sched_setscheduler(pid, policy, param); |
6449 | } |
6450 | |
6451 | /** |
6452 | * sys_sched_setparam - set/change the RT priority of a thread |
6453 | * @pid: the pid in question. |
6454 | * @param: structure containing the new RT priority. |
6455 | */ |
6456 | SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) |
6457 | { |
6458 | return do_sched_setscheduler(pid, -1, param); |
6459 | } |
6460 | |
6461 | /** |
6462 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread |
6463 | * @pid: the pid in question. |
6464 | */ |
6465 | SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) |
6466 | { |
6467 | struct task_struct *p; |
6468 | int retval; |
6469 | |
6470 | if (pid < 0) |
6471 | return -EINVAL; |
6472 | |
6473 | retval = -ESRCH; |
6474 | read_lock(&tasklist_lock); |
6475 | p = find_process_by_pid(pid); |
6476 | if (p) { |
6477 | retval = security_task_getscheduler(p); |
6478 | if (!retval) |
6479 | retval = p->policy |
6480 | | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); |
6481 | } |
6482 | read_unlock(&tasklist_lock); |
6483 | return retval; |
6484 | } |
6485 | |
6486 | /** |
6487 | * sys_sched_getparam - get the RT priority of a thread |
6488 | * @pid: the pid in question. |
6489 | * @param: structure containing the RT priority. |
6490 | */ |
6491 | SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) |
6492 | { |
6493 | struct sched_param lp; |
6494 | struct task_struct *p; |
6495 | int retval; |
6496 | |
6497 | if (!param || pid < 0) |
6498 | return -EINVAL; |
6499 | |
6500 | read_lock(&tasklist_lock); |
6501 | p = find_process_by_pid(pid); |
6502 | retval = -ESRCH; |
6503 | if (!p) |
6504 | goto out_unlock; |
6505 | |
6506 | retval = security_task_getscheduler(p); |
6507 | if (retval) |
6508 | goto out_unlock; |
6509 | |
6510 | lp.sched_priority = p->rt_priority; |
6511 | read_unlock(&tasklist_lock); |
6512 | |
6513 | /* |
6514 | * This one might sleep, we cannot do it with a spinlock held ... |
6515 | */ |
6516 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; |
6517 | |
6518 | return retval; |
6519 | |
6520 | out_unlock: |
6521 | read_unlock(&tasklist_lock); |
6522 | return retval; |
6523 | } |
6524 | |
6525 | long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) |
6526 | { |
6527 | cpumask_var_t cpus_allowed, new_mask; |
6528 | struct task_struct *p; |
6529 | int retval; |
6530 | |
6531 | get_online_cpus(); |
6532 | read_lock(&tasklist_lock); |
6533 | |
6534 | p = find_process_by_pid(pid); |
6535 | if (!p) { |
6536 | read_unlock(&tasklist_lock); |
6537 | put_online_cpus(); |
6538 | return -ESRCH; |
6539 | } |
6540 | |
6541 | /* |
6542 | * It is not safe to call set_cpus_allowed with the |
6543 | * tasklist_lock held. We will bump the task_struct's |
6544 | * usage count and then drop tasklist_lock. |
6545 | */ |
6546 | get_task_struct(p); |
6547 | read_unlock(&tasklist_lock); |
6548 | |
6549 | if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { |
6550 | retval = -ENOMEM; |
6551 | goto out_put_task; |
6552 | } |
6553 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { |
6554 | retval = -ENOMEM; |
6555 | goto out_free_cpus_allowed; |
6556 | } |
6557 | retval = -EPERM; |
6558 | if (!check_same_owner(p) && !capable(CAP_SYS_NICE)) |
6559 | goto out_unlock; |
6560 | |
6561 | retval = security_task_setscheduler(p, 0, NULL); |
6562 | if (retval) |
6563 | goto out_unlock; |
6564 | |
6565 | cpuset_cpus_allowed(p, cpus_allowed); |
6566 | cpumask_and(new_mask, in_mask, cpus_allowed); |
6567 | again: |
6568 | retval = set_cpus_allowed_ptr(p, new_mask); |
6569 | |
6570 | if (!retval) { |
6571 | cpuset_cpus_allowed(p, cpus_allowed); |
6572 | if (!cpumask_subset(new_mask, cpus_allowed)) { |
6573 | /* |
6574 | * We must have raced with a concurrent cpuset |
6575 | * update. Just reset the cpus_allowed to the |
6576 | * cpuset's cpus_allowed |
6577 | */ |
6578 | cpumask_copy(new_mask, cpus_allowed); |
6579 | goto again; |
6580 | } |
6581 | } |
6582 | out_unlock: |
6583 | free_cpumask_var(new_mask); |
6584 | out_free_cpus_allowed: |
6585 | free_cpumask_var(cpus_allowed); |
6586 | out_put_task: |
6587 | put_task_struct(p); |
6588 | put_online_cpus(); |
6589 | return retval; |
6590 | } |
6591 | |
6592 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, |
6593 | struct cpumask *new_mask) |
6594 | { |
6595 | if (len < cpumask_size()) |
6596 | cpumask_clear(new_mask); |
6597 | else if (len > cpumask_size()) |
6598 | len = cpumask_size(); |
6599 | |
6600 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
6601 | } |
6602 | |
6603 | /** |
6604 | * sys_sched_setaffinity - set the cpu affinity of a process |
6605 | * @pid: pid of the process |
6606 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
6607 | * @user_mask_ptr: user-space pointer to the new cpu mask |
6608 | */ |
6609 | SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, |
6610 | unsigned long __user *, user_mask_ptr) |
6611 | { |
6612 | cpumask_var_t new_mask; |
6613 | int retval; |
6614 | |
6615 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) |
6616 | return -ENOMEM; |
6617 | |
6618 | retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); |
6619 | if (retval == 0) |
6620 | retval = sched_setaffinity(pid, new_mask); |
6621 | free_cpumask_var(new_mask); |
6622 | return retval; |
6623 | } |
6624 | |
6625 | long sched_getaffinity(pid_t pid, struct cpumask *mask) |
6626 | { |
6627 | struct task_struct *p; |
6628 | int retval; |
6629 | |
6630 | get_online_cpus(); |
6631 | read_lock(&tasklist_lock); |
6632 | |
6633 | retval = -ESRCH; |
6634 | p = find_process_by_pid(pid); |
6635 | if (!p) |
6636 | goto out_unlock; |
6637 | |
6638 | retval = security_task_getscheduler(p); |
6639 | if (retval) |
6640 | goto out_unlock; |
6641 | |
6642 | cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); |
6643 | |
6644 | out_unlock: |
6645 | read_unlock(&tasklist_lock); |
6646 | put_online_cpus(); |
6647 | |
6648 | return retval; |
6649 | } |
6650 | |
6651 | /** |
6652 | * sys_sched_getaffinity - get the cpu affinity of a process |
6653 | * @pid: pid of the process |
6654 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
6655 | * @user_mask_ptr: user-space pointer to hold the current cpu mask |
6656 | */ |
6657 | SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, |
6658 | unsigned long __user *, user_mask_ptr) |
6659 | { |
6660 | int ret; |
6661 | cpumask_var_t mask; |
6662 | |
6663 | if (len < cpumask_size()) |
6664 | return -EINVAL; |
6665 | |
6666 | if (!alloc_cpumask_var(&mask, GFP_KERNEL)) |
6667 | return -ENOMEM; |
6668 | |
6669 | ret = sched_getaffinity(pid, mask); |
6670 | if (ret == 0) { |
6671 | if (copy_to_user(user_mask_ptr, mask, cpumask_size())) |
6672 | ret = -EFAULT; |
6673 | else |
6674 | ret = cpumask_size(); |
6675 | } |
6676 | free_cpumask_var(mask); |
6677 | |
6678 | return ret; |
6679 | } |
6680 | |
6681 | /** |
6682 | * sys_sched_yield - yield the current processor to other threads. |
6683 | * |
6684 | * This function yields the current CPU to other tasks. If there are no |
6685 | * other threads running on this CPU then this function will return. |
6686 | */ |
6687 | SYSCALL_DEFINE0(sched_yield) |
6688 | { |
6689 | struct rq *rq = this_rq_lock(); |
6690 | |
6691 | schedstat_inc(rq, yld_count); |
6692 | current->sched_class->yield_task(rq); |
6693 | |
6694 | /* |
6695 | * Since we are going to call schedule() anyway, there's |
6696 | * no need to preempt or enable interrupts: |
6697 | */ |
6698 | __release(rq->lock); |
6699 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
6700 | _raw_spin_unlock(&rq->lock); |
6701 | preempt_enable_no_resched(); |
6702 | |
6703 | schedule(); |
6704 | |
6705 | return 0; |
6706 | } |
6707 | |
6708 | static inline int should_resched(void) |
6709 | { |
6710 | return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); |
6711 | } |
6712 | |
6713 | static void __cond_resched(void) |
6714 | { |
6715 | add_preempt_count(PREEMPT_ACTIVE); |
6716 | schedule(); |
6717 | sub_preempt_count(PREEMPT_ACTIVE); |
6718 | } |
6719 | |
6720 | int __sched _cond_resched(void) |
6721 | { |
6722 | if (should_resched()) { |
6723 | __cond_resched(); |
6724 | return 1; |
6725 | } |
6726 | return 0; |
6727 | } |
6728 | EXPORT_SYMBOL(_cond_resched); |
6729 | |
6730 | /* |
6731 | * __cond_resched_lock() - if a reschedule is pending, drop the given lock, |
6732 | * call schedule, and on return reacquire the lock. |
6733 | * |
6734 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
6735 | * operations here to prevent schedule() from being called twice (once via |
6736 | * spin_unlock(), once by hand). |
6737 | */ |
6738 | int __cond_resched_lock(spinlock_t *lock) |
6739 | { |
6740 | int resched = should_resched(); |
6741 | int ret = 0; |
6742 | |
6743 | lockdep_assert_held(lock); |
6744 | |
6745 | if (spin_needbreak(lock) || resched) { |
6746 | spin_unlock(lock); |
6747 | if (resched) |
6748 | __cond_resched(); |
6749 | else |
6750 | cpu_relax(); |
6751 | ret = 1; |
6752 | spin_lock(lock); |
6753 | } |
6754 | return ret; |
6755 | } |
6756 | EXPORT_SYMBOL(__cond_resched_lock); |
6757 | |
6758 | int __sched __cond_resched_softirq(void) |
6759 | { |
6760 | BUG_ON(!in_softirq()); |
6761 | |
6762 | if (should_resched()) { |
6763 | local_bh_enable(); |
6764 | __cond_resched(); |
6765 | local_bh_disable(); |
6766 | return 1; |
6767 | } |
6768 | return 0; |
6769 | } |
6770 | EXPORT_SYMBOL(__cond_resched_softirq); |
6771 | |
6772 | /** |
6773 | * yield - yield the current processor to other threads. |
6774 | * |
6775 | * This is a shortcut for kernel-space yielding - it marks the |
6776 | * thread runnable and calls sys_sched_yield(). |
6777 | */ |
6778 | void __sched yield(void) |
6779 | { |
6780 | set_current_state(TASK_RUNNING); |
6781 | sys_sched_yield(); |
6782 | } |
6783 | EXPORT_SYMBOL(yield); |
6784 | |
6785 | /* |
6786 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
6787 | * that process accounting knows that this is a task in IO wait state. |
6788 | */ |
6789 | void __sched io_schedule(void) |
6790 | { |
6791 | struct rq *rq = raw_rq(); |
6792 | |
6793 | delayacct_blkio_start(); |
6794 | atomic_inc(&rq->nr_iowait); |
6795 | current->in_iowait = 1; |
6796 | schedule(); |
6797 | current->in_iowait = 0; |
6798 | atomic_dec(&rq->nr_iowait); |
6799 | delayacct_blkio_end(); |
6800 | } |
6801 | EXPORT_SYMBOL(io_schedule); |
6802 | |
6803 | long __sched io_schedule_timeout(long timeout) |
6804 | { |
6805 | struct rq *rq = raw_rq(); |
6806 | long ret; |
6807 | |
6808 | delayacct_blkio_start(); |
6809 | atomic_inc(&rq->nr_iowait); |
6810 | current->in_iowait = 1; |
6811 | ret = schedule_timeout(timeout); |
6812 | current->in_iowait = 0; |
6813 | atomic_dec(&rq->nr_iowait); |
6814 | delayacct_blkio_end(); |
6815 | return ret; |
6816 | } |
6817 | |
6818 | /** |
6819 | * sys_sched_get_priority_max - return maximum RT priority. |
6820 | * @policy: scheduling class. |
6821 | * |
6822 | * this syscall returns the maximum rt_priority that can be used |
6823 | * by a given scheduling class. |
6824 | */ |
6825 | SYSCALL_DEFINE1(sched_get_priority_max, int, policy) |
6826 | { |
6827 | int ret = -EINVAL; |
6828 | |
6829 | switch (policy) { |
6830 | case SCHED_FIFO: |
6831 | case SCHED_RR: |
6832 | ret = MAX_USER_RT_PRIO-1; |
6833 | break; |
6834 | case SCHED_NORMAL: |
6835 | case SCHED_BATCH: |
6836 | case SCHED_IDLE: |
6837 | ret = 0; |
6838 | break; |
6839 | } |
6840 | return ret; |
6841 | } |
6842 | |
6843 | /** |
6844 | * sys_sched_get_priority_min - return minimum RT priority. |
6845 | * @policy: scheduling class. |
6846 | * |
6847 | * this syscall returns the minimum rt_priority that can be used |
6848 | * by a given scheduling class. |
6849 | */ |
6850 | SYSCALL_DEFINE1(sched_get_priority_min, int, policy) |
6851 | { |
6852 | int ret = -EINVAL; |
6853 | |
6854 | switch (policy) { |
6855 | case SCHED_FIFO: |
6856 | case SCHED_RR: |
6857 | ret = 1; |
6858 | break; |
6859 | case SCHED_NORMAL: |
6860 | case SCHED_BATCH: |
6861 | case SCHED_IDLE: |
6862 | ret = 0; |
6863 | } |
6864 | return ret; |
6865 | } |
6866 | |
6867 | /** |
6868 | * sys_sched_rr_get_interval - return the default timeslice of a process. |
6869 | * @pid: pid of the process. |
6870 | * @interval: userspace pointer to the timeslice value. |
6871 | * |
6872 | * this syscall writes the default timeslice value of a given process |
6873 | * into the user-space timespec buffer. A value of '0' means infinity. |
6874 | */ |
6875 | SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, |
6876 | struct timespec __user *, interval) |
6877 | { |
6878 | struct task_struct *p; |
6879 | unsigned int time_slice; |
6880 | int retval; |
6881 | struct timespec t; |
6882 | |
6883 | if (pid < 0) |
6884 | return -EINVAL; |
6885 | |
6886 | retval = -ESRCH; |
6887 | read_lock(&tasklist_lock); |
6888 | p = find_process_by_pid(pid); |
6889 | if (!p) |
6890 | goto out_unlock; |
6891 | |
6892 | retval = security_task_getscheduler(p); |
6893 | if (retval) |
6894 | goto out_unlock; |
6895 | |
6896 | time_slice = p->sched_class->get_rr_interval(p); |
6897 | |
6898 | read_unlock(&tasklist_lock); |
6899 | jiffies_to_timespec(time_slice, &t); |
6900 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
6901 | return retval; |
6902 | |
6903 | out_unlock: |
6904 | read_unlock(&tasklist_lock); |
6905 | return retval; |
6906 | } |
6907 | |
6908 | static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; |
6909 | |
6910 | void sched_show_task(struct task_struct *p) |
6911 | { |
6912 | unsigned long free = 0; |
6913 | unsigned state; |
6914 | |
6915 | state = p->state ? __ffs(p->state) + 1 : 0; |
6916 | printk(KERN_INFO "%-13.13s %c", p->comm, |
6917 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
6918 | #if BITS_PER_LONG == 32 |
6919 | if (state == TASK_RUNNING) |
6920 | printk(KERN_CONT " running "); |
6921 | else |
6922 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
6923 | #else |
6924 | if (state == TASK_RUNNING) |
6925 | printk(KERN_CONT " running task "); |
6926 | else |
6927 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
6928 | #endif |
6929 | #ifdef CONFIG_DEBUG_STACK_USAGE |
6930 | free = stack_not_used(p); |
6931 | #endif |
6932 | printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, |
6933 | task_pid_nr(p), task_pid_nr(p->real_parent), |
6934 | (unsigned long)task_thread_info(p)->flags); |
6935 | |
6936 | show_stack(p, NULL); |
6937 | } |
6938 | |
6939 | void show_state_filter(unsigned long state_filter) |
6940 | { |
6941 | struct task_struct *g, *p; |
6942 | |
6943 | #if BITS_PER_LONG == 32 |
6944 | printk(KERN_INFO |
6945 | " task PC stack pid father\n"); |
6946 | #else |
6947 | printk(KERN_INFO |
6948 | " task PC stack pid father\n"); |
6949 | #endif |
6950 | read_lock(&tasklist_lock); |
6951 | do_each_thread(g, p) { |
6952 | /* |
6953 | * reset the NMI-timeout, listing all files on a slow |
6954 | * console might take alot of time: |
6955 | */ |
6956 | touch_nmi_watchdog(); |
6957 | if (!state_filter || (p->state & state_filter)) |
6958 | sched_show_task(p); |
6959 | } while_each_thread(g, p); |
6960 | |
6961 | touch_all_softlockup_watchdogs(); |
6962 | |
6963 | #ifdef CONFIG_SCHED_DEBUG |
6964 | sysrq_sched_debug_show(); |
6965 | #endif |
6966 | read_unlock(&tasklist_lock); |
6967 | /* |
6968 | * Only show locks if all tasks are dumped: |
6969 | */ |
6970 | if (state_filter == -1) |
6971 | debug_show_all_locks(); |
6972 | } |
6973 | |
6974 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
6975 | { |
6976 | idle->sched_class = &idle_sched_class; |
6977 | } |
6978 | |
6979 | /** |
6980 | * init_idle - set up an idle thread for a given CPU |
6981 | * @idle: task in question |
6982 | * @cpu: cpu the idle task belongs to |
6983 | * |
6984 | * NOTE: this function does not set the idle thread's NEED_RESCHED |
6985 | * flag, to make booting more robust. |
6986 | */ |
6987 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
6988 | { |
6989 | struct rq *rq = cpu_rq(cpu); |
6990 | unsigned long flags; |
6991 | |
6992 | spin_lock_irqsave(&rq->lock, flags); |
6993 | |
6994 | __sched_fork(idle); |
6995 | idle->se.exec_start = sched_clock(); |
6996 | |
6997 | cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu)); |
6998 | __set_task_cpu(idle, cpu); |
6999 | |
7000 | rq->curr = rq->idle = idle; |
7001 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
7002 | idle->oncpu = 1; |
7003 | #endif |
7004 | spin_unlock_irqrestore(&rq->lock, flags); |
7005 | |
7006 | /* Set the preempt count _outside_ the spinlocks! */ |
7007 | #if defined(CONFIG_PREEMPT) |
7008 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
7009 | #else |
7010 | task_thread_info(idle)->preempt_count = 0; |
7011 | #endif |
7012 | /* |
7013 | * The idle tasks have their own, simple scheduling class: |
7014 | */ |
7015 | idle->sched_class = &idle_sched_class; |
7016 | ftrace_graph_init_task(idle); |
7017 | } |
7018 | |
7019 | /* |
7020 | * In a system that switches off the HZ timer nohz_cpu_mask |
7021 | * indicates which cpus entered this state. This is used |
7022 | * in the rcu update to wait only for active cpus. For system |
7023 | * which do not switch off the HZ timer nohz_cpu_mask should |
7024 | * always be CPU_BITS_NONE. |
7025 | */ |
7026 | cpumask_var_t nohz_cpu_mask; |
7027 | |
7028 | /* |
7029 | * Increase the granularity value when there are more CPUs, |
7030 | * because with more CPUs the 'effective latency' as visible |
7031 | * to users decreases. But the relationship is not linear, |
7032 | * so pick a second-best guess by going with the log2 of the |
7033 | * number of CPUs. |
7034 | * |
7035 | * This idea comes from the SD scheduler of Con Kolivas: |
7036 | */ |
7037 | static void update_sysctl(void) |
7038 | { |
7039 | unsigned int cpus = min(num_online_cpus(), 8U); |
7040 | unsigned int factor = 1 + ilog2(cpus); |
7041 | |
7042 | #define SET_SYSCTL(name) \ |
7043 | (sysctl_##name = (factor) * normalized_sysctl_##name) |
7044 | SET_SYSCTL(sched_min_granularity); |
7045 | SET_SYSCTL(sched_latency); |
7046 | SET_SYSCTL(sched_wakeup_granularity); |
7047 | SET_SYSCTL(sched_shares_ratelimit); |
7048 | #undef SET_SYSCTL |
7049 | } |
7050 | |
7051 | static inline void sched_init_granularity(void) |
7052 | { |
7053 | update_sysctl(); |
7054 | } |
7055 | |
7056 | #ifdef CONFIG_SMP |
7057 | /* |
7058 | * This is how migration works: |
7059 | * |
7060 | * 1) we queue a struct migration_req structure in the source CPU's |
7061 | * runqueue and wake up that CPU's migration thread. |
7062 | * 2) we down() the locked semaphore => thread blocks. |
7063 | * 3) migration thread wakes up (implicitly it forces the migrated |
7064 | * thread off the CPU) |
7065 | * 4) it gets the migration request and checks whether the migrated |
7066 | * task is still in the wrong runqueue. |
7067 | * 5) if it's in the wrong runqueue then the migration thread removes |
7068 | * it and puts it into the right queue. |
7069 | * 6) migration thread up()s the semaphore. |
7070 | * 7) we wake up and the migration is done. |
7071 | */ |
7072 | |
7073 | /* |
7074 | * Change a given task's CPU affinity. Migrate the thread to a |
7075 | * proper CPU and schedule it away if the CPU it's executing on |
7076 | * is removed from the allowed bitmask. |
7077 | * |
7078 | * NOTE: the caller must have a valid reference to the task, the |
7079 | * task must not exit() & deallocate itself prematurely. The |
7080 | * call is not atomic; no spinlocks may be held. |
7081 | */ |
7082 | int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) |
7083 | { |
7084 | struct migration_req req; |
7085 | unsigned long flags; |
7086 | struct rq *rq; |
7087 | int ret = 0; |
7088 | |
7089 | rq = task_rq_lock(p, &flags); |
7090 | if (!cpumask_intersects(new_mask, cpu_active_mask)) { |
7091 | ret = -EINVAL; |
7092 | goto out; |
7093 | } |
7094 | |
7095 | if (unlikely((p->flags & PF_THREAD_BOUND) && p != current && |
7096 | !cpumask_equal(&p->cpus_allowed, new_mask))) { |
7097 | ret = -EINVAL; |
7098 | goto out; |
7099 | } |
7100 | |
7101 | if (p->sched_class->set_cpus_allowed) |
7102 | p->sched_class->set_cpus_allowed(p, new_mask); |
7103 | else { |
7104 | cpumask_copy(&p->cpus_allowed, new_mask); |
7105 | p->rt.nr_cpus_allowed = cpumask_weight(new_mask); |
7106 | } |
7107 | |
7108 | /* Can the task run on the task's current CPU? If so, we're done */ |
7109 | if (cpumask_test_cpu(task_cpu(p), new_mask)) |
7110 | goto out; |
7111 | |
7112 | if (migrate_task(p, cpumask_any_and(cpu_active_mask, new_mask), &req)) { |
7113 | /* Need help from migration thread: drop lock and wait. */ |
7114 | struct task_struct *mt = rq->migration_thread; |
7115 | |
7116 | get_task_struct(mt); |
7117 | task_rq_unlock(rq, &flags); |
7118 | wake_up_process(rq->migration_thread); |
7119 | put_task_struct(mt); |
7120 | wait_for_completion(&req.done); |
7121 | tlb_migrate_finish(p->mm); |
7122 | return 0; |
7123 | } |
7124 | out: |
7125 | task_rq_unlock(rq, &flags); |
7126 | |
7127 | return ret; |
7128 | } |
7129 | EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); |
7130 | |
7131 | /* |
7132 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
7133 | * this because either it can't run here any more (set_cpus_allowed() |
7134 | * away from this CPU, or CPU going down), or because we're |
7135 | * attempting to rebalance this task on exec (sched_exec). |
7136 | * |
7137 | * So we race with normal scheduler movements, but that's OK, as long |
7138 | * as the task is no longer on this CPU. |
7139 | * |
7140 | * Returns non-zero if task was successfully migrated. |
7141 | */ |
7142 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
7143 | { |
7144 | struct rq *rq_dest, *rq_src; |
7145 | int ret = 0, on_rq; |
7146 | |
7147 | if (unlikely(!cpu_active(dest_cpu))) |
7148 | return ret; |
7149 | |
7150 | rq_src = cpu_rq(src_cpu); |
7151 | rq_dest = cpu_rq(dest_cpu); |
7152 | |
7153 | double_rq_lock(rq_src, rq_dest); |
7154 | /* Already moved. */ |
7155 | if (task_cpu(p) != src_cpu) |
7156 | goto done; |
7157 | /* Affinity changed (again). */ |
7158 | if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)) |
7159 | goto fail; |
7160 | |
7161 | on_rq = p->se.on_rq; |
7162 | if (on_rq) |
7163 | deactivate_task(rq_src, p, 0); |
7164 | |
7165 | set_task_cpu(p, dest_cpu); |
7166 | if (on_rq) { |
7167 | activate_task(rq_dest, p, 0); |
7168 | check_preempt_curr(rq_dest, p, 0); |
7169 | } |
7170 | done: |
7171 | ret = 1; |
7172 | fail: |
7173 | double_rq_unlock(rq_src, rq_dest); |
7174 | return ret; |
7175 | } |
7176 | |
7177 | #define RCU_MIGRATION_IDLE 0 |
7178 | #define RCU_MIGRATION_NEED_QS 1 |
7179 | #define RCU_MIGRATION_GOT_QS 2 |
7180 | #define RCU_MIGRATION_MUST_SYNC 3 |
7181 | |
7182 | /* |
7183 | * migration_thread - this is a highprio system thread that performs |
7184 | * thread migration by bumping thread off CPU then 'pushing' onto |
7185 | * another runqueue. |
7186 | */ |
7187 | static int migration_thread(void *data) |
7188 | { |
7189 | int badcpu; |
7190 | int cpu = (long)data; |
7191 | struct rq *rq; |
7192 | |
7193 | rq = cpu_rq(cpu); |
7194 | BUG_ON(rq->migration_thread != current); |
7195 | |
7196 | set_current_state(TASK_INTERRUPTIBLE); |
7197 | while (!kthread_should_stop()) { |
7198 | struct migration_req *req; |
7199 | struct list_head *head; |
7200 | |
7201 | spin_lock_irq(&rq->lock); |
7202 | |
7203 | if (cpu_is_offline(cpu)) { |
7204 | spin_unlock_irq(&rq->lock); |
7205 | break; |
7206 | } |
7207 | |
7208 | if (rq->active_balance) { |
7209 | active_load_balance(rq, cpu); |
7210 | rq->active_balance = 0; |
7211 | } |
7212 | |
7213 | head = &rq->migration_queue; |
7214 | |
7215 | if (list_empty(head)) { |
7216 | spin_unlock_irq(&rq->lock); |
7217 | schedule(); |
7218 | set_current_state(TASK_INTERRUPTIBLE); |
7219 | continue; |
7220 | } |
7221 | req = list_entry(head->next, struct migration_req, list); |
7222 | list_del_init(head->next); |
7223 | |
7224 | if (req->task != NULL) { |
7225 | spin_unlock(&rq->lock); |
7226 | __migrate_task(req->task, cpu, req->dest_cpu); |
7227 | } else if (likely(cpu == (badcpu = smp_processor_id()))) { |
7228 | req->dest_cpu = RCU_MIGRATION_GOT_QS; |
7229 | spin_unlock(&rq->lock); |
7230 | } else { |
7231 | req->dest_cpu = RCU_MIGRATION_MUST_SYNC; |
7232 | spin_unlock(&rq->lock); |
7233 | WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu, cpu); |
7234 | } |
7235 | local_irq_enable(); |
7236 | |
7237 | complete(&req->done); |
7238 | } |
7239 | __set_current_state(TASK_RUNNING); |
7240 | |
7241 | return 0; |
7242 | } |
7243 | |
7244 | #ifdef CONFIG_HOTPLUG_CPU |
7245 | |
7246 | static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) |
7247 | { |
7248 | int ret; |
7249 | |
7250 | local_irq_disable(); |
7251 | ret = __migrate_task(p, src_cpu, dest_cpu); |
7252 | local_irq_enable(); |
7253 | return ret; |
7254 | } |
7255 | |
7256 | /* |
7257 | * Figure out where task on dead CPU should go, use force if necessary. |
7258 | */ |
7259 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
7260 | { |
7261 | int dest_cpu; |
7262 | const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(dead_cpu)); |
7263 | |
7264 | again: |
7265 | /* Look for allowed, online CPU in same node. */ |
7266 | for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask) |
7267 | if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed)) |
7268 | goto move; |
7269 | |
7270 | /* Any allowed, online CPU? */ |
7271 | dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask); |
7272 | if (dest_cpu < nr_cpu_ids) |
7273 | goto move; |
7274 | |
7275 | /* No more Mr. Nice Guy. */ |
7276 | if (dest_cpu >= nr_cpu_ids) { |
7277 | cpuset_cpus_allowed_locked(p, &p->cpus_allowed); |
7278 | dest_cpu = cpumask_any_and(cpu_active_mask, &p->cpus_allowed); |
7279 | |
7280 | /* |
7281 | * Don't tell them about moving exiting tasks or |
7282 | * kernel threads (both mm NULL), since they never |
7283 | * leave kernel. |
7284 | */ |
7285 | if (p->mm && printk_ratelimit()) { |
7286 | printk(KERN_INFO "process %d (%s) no " |
7287 | "longer affine to cpu%d\n", |
7288 | task_pid_nr(p), p->comm, dead_cpu); |
7289 | } |
7290 | } |
7291 | |
7292 | move: |
7293 | /* It can have affinity changed while we were choosing. */ |
7294 | if (unlikely(!__migrate_task_irq(p, dead_cpu, dest_cpu))) |
7295 | goto again; |
7296 | } |
7297 | |
7298 | /* |
7299 | * While a dead CPU has no uninterruptible tasks queued at this point, |
7300 | * it might still have a nonzero ->nr_uninterruptible counter, because |
7301 | * for performance reasons the counter is not stricly tracking tasks to |
7302 | * their home CPUs. So we just add the counter to another CPU's counter, |
7303 | * to keep the global sum constant after CPU-down: |
7304 | */ |
7305 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
7306 | { |
7307 | struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask)); |
7308 | unsigned long flags; |
7309 | |
7310 | local_irq_save(flags); |
7311 | double_rq_lock(rq_src, rq_dest); |
7312 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; |
7313 | rq_src->nr_uninterruptible = 0; |
7314 | double_rq_unlock(rq_src, rq_dest); |
7315 | local_irq_restore(flags); |
7316 | } |
7317 | |
7318 | /* Run through task list and migrate tasks from the dead cpu. */ |
7319 | static void migrate_live_tasks(int src_cpu) |
7320 | { |
7321 | struct task_struct *p, *t; |
7322 | |
7323 | read_lock(&tasklist_lock); |
7324 | |
7325 | do_each_thread(t, p) { |
7326 | if (p == current) |
7327 | continue; |
7328 | |
7329 | if (task_cpu(p) == src_cpu) |
7330 | move_task_off_dead_cpu(src_cpu, p); |
7331 | } while_each_thread(t, p); |
7332 | |
7333 | read_unlock(&tasklist_lock); |
7334 | } |
7335 | |
7336 | /* |
7337 | * Schedules idle task to be the next runnable task on current CPU. |
7338 | * It does so by boosting its priority to highest possible. |
7339 | * Used by CPU offline code. |
7340 | */ |
7341 | void sched_idle_next(void) |
7342 | { |
7343 | int this_cpu = smp_processor_id(); |
7344 | struct rq *rq = cpu_rq(this_cpu); |
7345 | struct task_struct *p = rq->idle; |
7346 | unsigned long flags; |
7347 | |
7348 | /* cpu has to be offline */ |
7349 | BUG_ON(cpu_online(this_cpu)); |
7350 | |
7351 | /* |
7352 | * Strictly not necessary since rest of the CPUs are stopped by now |
7353 | * and interrupts disabled on the current cpu. |
7354 | */ |
7355 | spin_lock_irqsave(&rq->lock, flags); |
7356 | |
7357 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
7358 | |
7359 | update_rq_clock(rq); |
7360 | activate_task(rq, p, 0); |
7361 | |
7362 | spin_unlock_irqrestore(&rq->lock, flags); |
7363 | } |
7364 | |
7365 | /* |
7366 | * Ensures that the idle task is using init_mm right before its cpu goes |
7367 | * offline. |
7368 | */ |
7369 | void idle_task_exit(void) |
7370 | { |
7371 | struct mm_struct *mm = current->active_mm; |
7372 | |
7373 | BUG_ON(cpu_online(smp_processor_id())); |
7374 | |
7375 | if (mm != &init_mm) |
7376 | switch_mm(mm, &init_mm, current); |
7377 | mmdrop(mm); |
7378 | } |
7379 | |
7380 | /* called under rq->lock with disabled interrupts */ |
7381 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
7382 | { |
7383 | struct rq *rq = cpu_rq(dead_cpu); |
7384 | |
7385 | /* Must be exiting, otherwise would be on tasklist. */ |
7386 | BUG_ON(!p->exit_state); |
7387 | |
7388 | /* Cannot have done final schedule yet: would have vanished. */ |
7389 | BUG_ON(p->state == TASK_DEAD); |
7390 | |
7391 | get_task_struct(p); |
7392 | |
7393 | /* |
7394 | * Drop lock around migration; if someone else moves it, |
7395 | * that's OK. No task can be added to this CPU, so iteration is |
7396 | * fine. |
7397 | */ |
7398 | spin_unlock_irq(&rq->lock); |
7399 | move_task_off_dead_cpu(dead_cpu, p); |
7400 | spin_lock_irq(&rq->lock); |
7401 | |
7402 | put_task_struct(p); |
7403 | } |
7404 | |
7405 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ |
7406 | static void migrate_dead_tasks(unsigned int dead_cpu) |
7407 | { |
7408 | struct rq *rq = cpu_rq(dead_cpu); |
7409 | struct task_struct *next; |
7410 | |
7411 | for ( ; ; ) { |
7412 | if (!rq->nr_running) |
7413 | break; |
7414 | update_rq_clock(rq); |
7415 | next = pick_next_task(rq); |
7416 | if (!next) |
7417 | break; |
7418 | next->sched_class->put_prev_task(rq, next); |
7419 | migrate_dead(dead_cpu, next); |
7420 | |
7421 | } |
7422 | } |
7423 | |
7424 | /* |
7425 | * remove the tasks which were accounted by rq from calc_load_tasks. |
7426 | */ |
7427 | static void calc_global_load_remove(struct rq *rq) |
7428 | { |
7429 | atomic_long_sub(rq->calc_load_active, &calc_load_tasks); |
7430 | rq->calc_load_active = 0; |
7431 | } |
7432 | #endif /* CONFIG_HOTPLUG_CPU */ |
7433 | |
7434 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
7435 | |
7436 | static struct ctl_table sd_ctl_dir[] = { |
7437 | { |
7438 | .procname = "sched_domain", |
7439 | .mode = 0555, |
7440 | }, |
7441 | {0, }, |
7442 | }; |
7443 | |
7444 | static struct ctl_table sd_ctl_root[] = { |
7445 | { |
7446 | .ctl_name = CTL_KERN, |
7447 | .procname = "kernel", |
7448 | .mode = 0555, |
7449 | .child = sd_ctl_dir, |
7450 | }, |
7451 | {0, }, |
7452 | }; |
7453 | |
7454 | static struct ctl_table *sd_alloc_ctl_entry(int n) |
7455 | { |
7456 | struct ctl_table *entry = |
7457 | kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
7458 | |
7459 | return entry; |
7460 | } |
7461 | |
7462 | static void sd_free_ctl_entry(struct ctl_table **tablep) |
7463 | { |
7464 | struct ctl_table *entry; |
7465 | |
7466 | /* |
7467 | * In the intermediate directories, both the child directory and |
7468 | * procname are dynamically allocated and could fail but the mode |
7469 | * will always be set. In the lowest directory the names are |
7470 | * static strings and all have proc handlers. |
7471 | */ |
7472 | for (entry = *tablep; entry->mode; entry++) { |
7473 | if (entry->child) |
7474 | sd_free_ctl_entry(&entry->child); |
7475 | if (entry->proc_handler == NULL) |
7476 | kfree(entry->procname); |
7477 | } |
7478 | |
7479 | kfree(*tablep); |
7480 | *tablep = NULL; |
7481 | } |
7482 | |
7483 | static void |
7484 | set_table_entry(struct ctl_table *entry, |
7485 | const char *procname, void *data, int maxlen, |
7486 | mode_t mode, proc_handler *proc_handler) |
7487 | { |
7488 | entry->procname = procname; |
7489 | entry->data = data; |
7490 | entry->maxlen = maxlen; |
7491 | entry->mode = mode; |
7492 | entry->proc_handler = proc_handler; |
7493 | } |
7494 | |
7495 | static struct ctl_table * |
7496 | sd_alloc_ctl_domain_table(struct sched_domain *sd) |
7497 | { |
7498 | struct ctl_table *table = sd_alloc_ctl_entry(13); |
7499 | |
7500 | if (table == NULL) |
7501 | return NULL; |
7502 | |
7503 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
7504 | sizeof(long), 0644, proc_doulongvec_minmax); |
7505 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
7506 | sizeof(long), 0644, proc_doulongvec_minmax); |
7507 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
7508 | sizeof(int), 0644, proc_dointvec_minmax); |
7509 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
7510 | sizeof(int), 0644, proc_dointvec_minmax); |
7511 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
7512 | sizeof(int), 0644, proc_dointvec_minmax); |
7513 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
7514 | sizeof(int), 0644, proc_dointvec_minmax); |
7515 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
7516 | sizeof(int), 0644, proc_dointvec_minmax); |
7517 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
7518 | sizeof(int), 0644, proc_dointvec_minmax); |
7519 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
7520 | sizeof(int), 0644, proc_dointvec_minmax); |
7521 | set_table_entry(&table[9], "cache_nice_tries", |
7522 | &sd->cache_nice_tries, |
7523 | sizeof(int), 0644, proc_dointvec_minmax); |
7524 | set_table_entry(&table[10], "flags", &sd->flags, |
7525 | sizeof(int), 0644, proc_dointvec_minmax); |
7526 | set_table_entry(&table[11], "name", sd->name, |
7527 | CORENAME_MAX_SIZE, 0444, proc_dostring); |
7528 | /* &table[12] is terminator */ |
7529 | |
7530 | return table; |
7531 | } |
7532 | |
7533 | static ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
7534 | { |
7535 | struct ctl_table *entry, *table; |
7536 | struct sched_domain *sd; |
7537 | int domain_num = 0, i; |
7538 | char buf[32]; |
7539 | |
7540 | for_each_domain(cpu, sd) |
7541 | domain_num++; |
7542 | entry = table = sd_alloc_ctl_entry(domain_num + 1); |
7543 | if (table == NULL) |
7544 | return NULL; |
7545 | |
7546 | i = 0; |
7547 | for_each_domain(cpu, sd) { |
7548 | snprintf(buf, 32, "domain%d", i); |
7549 | entry->procname = kstrdup(buf, GFP_KERNEL); |
7550 | entry->mode = 0555; |
7551 | entry->child = sd_alloc_ctl_domain_table(sd); |
7552 | entry++; |
7553 | i++; |
7554 | } |
7555 | return table; |
7556 | } |
7557 | |
7558 | static struct ctl_table_header *sd_sysctl_header; |
7559 | static void register_sched_domain_sysctl(void) |
7560 | { |
7561 | int i, cpu_num = num_possible_cpus(); |
7562 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); |
7563 | char buf[32]; |
7564 | |
7565 | WARN_ON(sd_ctl_dir[0].child); |
7566 | sd_ctl_dir[0].child = entry; |
7567 | |
7568 | if (entry == NULL) |
7569 | return; |
7570 | |
7571 | for_each_possible_cpu(i) { |
7572 | snprintf(buf, 32, "cpu%d", i); |
7573 | entry->procname = kstrdup(buf, GFP_KERNEL); |
7574 | entry->mode = 0555; |
7575 | entry->child = sd_alloc_ctl_cpu_table(i); |
7576 | entry++; |
7577 | } |
7578 | |
7579 | WARN_ON(sd_sysctl_header); |
7580 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
7581 | } |
7582 | |
7583 | /* may be called multiple times per register */ |
7584 | static void unregister_sched_domain_sysctl(void) |
7585 | { |
7586 | if (sd_sysctl_header) |
7587 | unregister_sysctl_table(sd_sysctl_header); |
7588 | sd_sysctl_header = NULL; |
7589 | if (sd_ctl_dir[0].child) |
7590 | sd_free_ctl_entry(&sd_ctl_dir[0].child); |
7591 | } |
7592 | #else |
7593 | static void register_sched_domain_sysctl(void) |
7594 | { |
7595 | } |
7596 | static void unregister_sched_domain_sysctl(void) |
7597 | { |
7598 | } |
7599 | #endif |
7600 | |
7601 | static void set_rq_online(struct rq *rq) |
7602 | { |
7603 | if (!rq->online) { |
7604 | const struct sched_class *class; |
7605 | |
7606 | cpumask_set_cpu(rq->cpu, rq->rd->online); |
7607 | rq->online = 1; |
7608 | |
7609 | for_each_class(class) { |
7610 | if (class->rq_online) |
7611 | class->rq_online(rq); |
7612 | } |
7613 | } |
7614 | } |
7615 | |
7616 | static void set_rq_offline(struct rq *rq) |
7617 | { |
7618 | if (rq->online) { |
7619 | const struct sched_class *class; |
7620 | |
7621 | for_each_class(class) { |
7622 | if (class->rq_offline) |
7623 | class->rq_offline(rq); |
7624 | } |
7625 | |
7626 | cpumask_clear_cpu(rq->cpu, rq->rd->online); |
7627 | rq->online = 0; |
7628 | } |
7629 | } |
7630 | |
7631 | /* |
7632 | * migration_call - callback that gets triggered when a CPU is added. |
7633 | * Here we can start up the necessary migration thread for the new CPU. |
7634 | */ |
7635 | static int __cpuinit |
7636 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) |
7637 | { |
7638 | struct task_struct *p; |
7639 | int cpu = (long)hcpu; |
7640 | unsigned long flags; |
7641 | struct rq *rq; |
7642 | |
7643 | switch (action) { |
7644 | |
7645 | case CPU_UP_PREPARE: |
7646 | case CPU_UP_PREPARE_FROZEN: |
7647 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
7648 | if (IS_ERR(p)) |
7649 | return NOTIFY_BAD; |
7650 | kthread_bind(p, cpu); |
7651 | /* Must be high prio: stop_machine expects to yield to it. */ |
7652 | rq = task_rq_lock(p, &flags); |
7653 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
7654 | task_rq_unlock(rq, &flags); |
7655 | get_task_struct(p); |
7656 | cpu_rq(cpu)->migration_thread = p; |
7657 | rq->calc_load_update = calc_load_update; |
7658 | break; |
7659 | |
7660 | case CPU_ONLINE: |
7661 | case CPU_ONLINE_FROZEN: |
7662 | /* Strictly unnecessary, as first user will wake it. */ |
7663 | wake_up_process(cpu_rq(cpu)->migration_thread); |
7664 | |
7665 | /* Update our root-domain */ |
7666 | rq = cpu_rq(cpu); |
7667 | spin_lock_irqsave(&rq->lock, flags); |
7668 | if (rq->rd) { |
7669 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
7670 | |
7671 | set_rq_online(rq); |
7672 | } |
7673 | spin_unlock_irqrestore(&rq->lock, flags); |
7674 | break; |
7675 | |
7676 | #ifdef CONFIG_HOTPLUG_CPU |
7677 | case CPU_UP_CANCELED: |
7678 | case CPU_UP_CANCELED_FROZEN: |
7679 | if (!cpu_rq(cpu)->migration_thread) |
7680 | break; |
7681 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
7682 | kthread_bind(cpu_rq(cpu)->migration_thread, |
7683 | cpumask_any(cpu_online_mask)); |
7684 | kthread_stop(cpu_rq(cpu)->migration_thread); |
7685 | put_task_struct(cpu_rq(cpu)->migration_thread); |
7686 | cpu_rq(cpu)->migration_thread = NULL; |
7687 | break; |
7688 | |
7689 | case CPU_DEAD: |
7690 | case CPU_DEAD_FROZEN: |
7691 | cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */ |
7692 | migrate_live_tasks(cpu); |
7693 | rq = cpu_rq(cpu); |
7694 | kthread_stop(rq->migration_thread); |
7695 | put_task_struct(rq->migration_thread); |
7696 | rq->migration_thread = NULL; |
7697 | /* Idle task back to normal (off runqueue, low prio) */ |
7698 | spin_lock_irq(&rq->lock); |
7699 | update_rq_clock(rq); |
7700 | deactivate_task(rq, rq->idle, 0); |
7701 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
7702 | rq->idle->sched_class = &idle_sched_class; |
7703 | migrate_dead_tasks(cpu); |
7704 | spin_unlock_irq(&rq->lock); |
7705 | cpuset_unlock(); |
7706 | migrate_nr_uninterruptible(rq); |
7707 | BUG_ON(rq->nr_running != 0); |
7708 | calc_global_load_remove(rq); |
7709 | /* |
7710 | * No need to migrate the tasks: it was best-effort if |
7711 | * they didn't take sched_hotcpu_mutex. Just wake up |
7712 | * the requestors. |
7713 | */ |
7714 | spin_lock_irq(&rq->lock); |
7715 | while (!list_empty(&rq->migration_queue)) { |
7716 | struct migration_req *req; |
7717 | |
7718 | req = list_entry(rq->migration_queue.next, |
7719 | struct migration_req, list); |
7720 | list_del_init(&req->list); |
7721 | spin_unlock_irq(&rq->lock); |
7722 | complete(&req->done); |
7723 | spin_lock_irq(&rq->lock); |
7724 | } |
7725 | spin_unlock_irq(&rq->lock); |
7726 | break; |
7727 | |
7728 | case CPU_DYING: |
7729 | case CPU_DYING_FROZEN: |
7730 | /* Update our root-domain */ |
7731 | rq = cpu_rq(cpu); |
7732 | spin_lock_irqsave(&rq->lock, flags); |
7733 | if (rq->rd) { |
7734 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
7735 | set_rq_offline(rq); |
7736 | } |
7737 | spin_unlock_irqrestore(&rq->lock, flags); |
7738 | break; |
7739 | #endif |
7740 | } |
7741 | return NOTIFY_OK; |
7742 | } |
7743 | |
7744 | /* |
7745 | * Register at high priority so that task migration (migrate_all_tasks) |
7746 | * happens before everything else. This has to be lower priority than |
7747 | * the notifier in the perf_event subsystem, though. |
7748 | */ |
7749 | static struct notifier_block __cpuinitdata migration_notifier = { |
7750 | .notifier_call = migration_call, |
7751 | .priority = 10 |
7752 | }; |
7753 | |
7754 | static int __init migration_init(void) |
7755 | { |
7756 | void *cpu = (void *)(long)smp_processor_id(); |
7757 | int err; |
7758 | |
7759 | /* Start one for the boot CPU: */ |
7760 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
7761 | BUG_ON(err == NOTIFY_BAD); |
7762 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
7763 | register_cpu_notifier(&migration_notifier); |
7764 | |
7765 | return 0; |
7766 | } |
7767 | early_initcall(migration_init); |
7768 | #endif |
7769 | |
7770 | #ifdef CONFIG_SMP |
7771 | |
7772 | #ifdef CONFIG_SCHED_DEBUG |
7773 | |
7774 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, |
7775 | struct cpumask *groupmask) |
7776 | { |
7777 | struct sched_group *group = sd->groups; |
7778 | char str[256]; |
7779 | |
7780 | cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); |
7781 | cpumask_clear(groupmask); |
7782 | |
7783 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); |
7784 | |
7785 | if (!(sd->flags & SD_LOAD_BALANCE)) { |
7786 | printk("does not load-balance\n"); |
7787 | if (sd->parent) |
7788 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
7789 | " has parent"); |
7790 | return -1; |
7791 | } |
7792 | |
7793 | printk(KERN_CONT "span %s level %s\n", str, sd->name); |
7794 | |
7795 | if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
7796 | printk(KERN_ERR "ERROR: domain->span does not contain " |
7797 | "CPU%d\n", cpu); |
7798 | } |
7799 | if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { |
7800 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
7801 | " CPU%d\n", cpu); |
7802 | } |
7803 | |
7804 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
7805 | do { |
7806 | if (!group) { |
7807 | printk("\n"); |
7808 | printk(KERN_ERR "ERROR: group is NULL\n"); |
7809 | break; |
7810 | } |
7811 | |
7812 | if (!group->cpu_power) { |
7813 | printk(KERN_CONT "\n"); |
7814 | printk(KERN_ERR "ERROR: domain->cpu_power not " |
7815 | "set\n"); |
7816 | break; |
7817 | } |
7818 | |
7819 | if (!cpumask_weight(sched_group_cpus(group))) { |
7820 | printk(KERN_CONT "\n"); |
7821 | printk(KERN_ERR "ERROR: empty group\n"); |
7822 | break; |
7823 | } |
7824 | |
7825 | if (cpumask_intersects(groupmask, sched_group_cpus(group))) { |
7826 | printk(KERN_CONT "\n"); |
7827 | printk(KERN_ERR "ERROR: repeated CPUs\n"); |
7828 | break; |
7829 | } |
7830 | |
7831 | cpumask_or(groupmask, groupmask, sched_group_cpus(group)); |
7832 | |
7833 | cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); |
7834 | |
7835 | printk(KERN_CONT " %s", str); |
7836 | if (group->cpu_power != SCHED_LOAD_SCALE) { |
7837 | printk(KERN_CONT " (cpu_power = %d)", |
7838 | group->cpu_power); |
7839 | } |
7840 | |
7841 | group = group->next; |
7842 | } while (group != sd->groups); |
7843 | printk(KERN_CONT "\n"); |
7844 | |
7845 | if (!cpumask_equal(sched_domain_span(sd), groupmask)) |
7846 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); |
7847 | |
7848 | if (sd->parent && |
7849 | !cpumask_subset(groupmask, sched_domain_span(sd->parent))) |
7850 | printk(KERN_ERR "ERROR: parent span is not a superset " |
7851 | "of domain->span\n"); |
7852 | return 0; |
7853 | } |
7854 | |
7855 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
7856 | { |
7857 | cpumask_var_t groupmask; |
7858 | int level = 0; |
7859 | |
7860 | if (!sd) { |
7861 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); |
7862 | return; |
7863 | } |
7864 | |
7865 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
7866 | |
7867 | if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) { |
7868 | printk(KERN_DEBUG "Cannot load-balance (out of memory)\n"); |
7869 | return; |
7870 | } |
7871 | |
7872 | for (;;) { |
7873 | if (sched_domain_debug_one(sd, cpu, level, groupmask)) |
7874 | break; |
7875 | level++; |
7876 | sd = sd->parent; |
7877 | if (!sd) |
7878 | break; |
7879 | } |
7880 | free_cpumask_var(groupmask); |
7881 | } |
7882 | #else /* !CONFIG_SCHED_DEBUG */ |
7883 | # define sched_domain_debug(sd, cpu) do { } while (0) |
7884 | #endif /* CONFIG_SCHED_DEBUG */ |
7885 | |
7886 | static int sd_degenerate(struct sched_domain *sd) |
7887 | { |
7888 | if (cpumask_weight(sched_domain_span(sd)) == 1) |
7889 | return 1; |
7890 | |
7891 | /* Following flags need at least 2 groups */ |
7892 | if (sd->flags & (SD_LOAD_BALANCE | |
7893 | SD_BALANCE_NEWIDLE | |
7894 | SD_BALANCE_FORK | |
7895 | SD_BALANCE_EXEC | |
7896 | SD_SHARE_CPUPOWER | |
7897 | SD_SHARE_PKG_RESOURCES)) { |
7898 | if (sd->groups != sd->groups->next) |
7899 | return 0; |
7900 | } |
7901 | |
7902 | /* Following flags don't use groups */ |
7903 | if (sd->flags & (SD_WAKE_AFFINE)) |
7904 | return 0; |
7905 | |
7906 | return 1; |
7907 | } |
7908 | |
7909 | static int |
7910 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) |
7911 | { |
7912 | unsigned long cflags = sd->flags, pflags = parent->flags; |
7913 | |
7914 | if (sd_degenerate(parent)) |
7915 | return 1; |
7916 | |
7917 | if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) |
7918 | return 0; |
7919 | |
7920 | /* Flags needing groups don't count if only 1 group in parent */ |
7921 | if (parent->groups == parent->groups->next) { |
7922 | pflags &= ~(SD_LOAD_BALANCE | |
7923 | SD_BALANCE_NEWIDLE | |
7924 | SD_BALANCE_FORK | |
7925 | SD_BALANCE_EXEC | |
7926 | SD_SHARE_CPUPOWER | |
7927 | SD_SHARE_PKG_RESOURCES); |
7928 | if (nr_node_ids == 1) |
7929 | pflags &= ~SD_SERIALIZE; |
7930 | } |
7931 | if (~cflags & pflags) |
7932 | return 0; |
7933 | |
7934 | return 1; |
7935 | } |
7936 | |
7937 | static void free_rootdomain(struct root_domain *rd) |
7938 | { |
7939 | synchronize_sched(); |
7940 | |
7941 | cpupri_cleanup(&rd->cpupri); |
7942 | |
7943 | free_cpumask_var(rd->rto_mask); |
7944 | free_cpumask_var(rd->online); |
7945 | free_cpumask_var(rd->span); |
7946 | kfree(rd); |
7947 | } |
7948 | |
7949 | static void rq_attach_root(struct rq *rq, struct root_domain *rd) |
7950 | { |
7951 | struct root_domain *old_rd = NULL; |
7952 | unsigned long flags; |
7953 | |
7954 | spin_lock_irqsave(&rq->lock, flags); |
7955 | |
7956 | if (rq->rd) { |
7957 | old_rd = rq->rd; |
7958 | |
7959 | if (cpumask_test_cpu(rq->cpu, old_rd->online)) |
7960 | set_rq_offline(rq); |
7961 | |
7962 | cpumask_clear_cpu(rq->cpu, old_rd->span); |
7963 | |
7964 | /* |
7965 | * If we dont want to free the old_rt yet then |
7966 | * set old_rd to NULL to skip the freeing later |
7967 | * in this function: |
7968 | */ |
7969 | if (!atomic_dec_and_test(&old_rd->refcount)) |
7970 | old_rd = NULL; |
7971 | } |
7972 | |
7973 | atomic_inc(&rd->refcount); |
7974 | rq->rd = rd; |
7975 | |
7976 | cpumask_set_cpu(rq->cpu, rd->span); |
7977 | if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) |
7978 | set_rq_online(rq); |
7979 | |
7980 | spin_unlock_irqrestore(&rq->lock, flags); |
7981 | |
7982 | if (old_rd) |
7983 | free_rootdomain(old_rd); |
7984 | } |
7985 | |
7986 | static int init_rootdomain(struct root_domain *rd, bool bootmem) |
7987 | { |
7988 | gfp_t gfp = GFP_KERNEL; |
7989 | |
7990 | memset(rd, 0, sizeof(*rd)); |
7991 | |
7992 | if (bootmem) |
7993 | gfp = GFP_NOWAIT; |
7994 | |
7995 | if (!alloc_cpumask_var(&rd->span, gfp)) |
7996 | goto out; |
7997 | if (!alloc_cpumask_var(&rd->online, gfp)) |
7998 | goto free_span; |
7999 | if (!alloc_cpumask_var(&rd->rto_mask, gfp)) |
8000 | goto free_online; |
8001 | |
8002 | if (cpupri_init(&rd->cpupri, bootmem) != 0) |
8003 | goto free_rto_mask; |
8004 | return 0; |
8005 | |
8006 | free_rto_mask: |
8007 | free_cpumask_var(rd->rto_mask); |
8008 | free_online: |
8009 | free_cpumask_var(rd->online); |
8010 | free_span: |
8011 | free_cpumask_var(rd->span); |
8012 | out: |
8013 | return -ENOMEM; |
8014 | } |
8015 | |
8016 | static void init_defrootdomain(void) |
8017 | { |
8018 | init_rootdomain(&def_root_domain, true); |
8019 | |
8020 | atomic_set(&def_root_domain.refcount, 1); |
8021 | } |
8022 | |
8023 | static struct root_domain *alloc_rootdomain(void) |
8024 | { |
8025 | struct root_domain *rd; |
8026 | |
8027 | rd = kmalloc(sizeof(*rd), GFP_KERNEL); |
8028 | if (!rd) |
8029 | return NULL; |
8030 | |
8031 | if (init_rootdomain(rd, false) != 0) { |
8032 | kfree(rd); |
8033 | return NULL; |
8034 | } |
8035 | |
8036 | return rd; |
8037 | } |
8038 | |
8039 | /* |
8040 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
8041 | * hold the hotplug lock. |
8042 | */ |
8043 | static void |
8044 | cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) |
8045 | { |
8046 | struct rq *rq = cpu_rq(cpu); |
8047 | struct sched_domain *tmp; |
8048 | |
8049 | /* Remove the sched domains which do not contribute to scheduling. */ |
8050 | for (tmp = sd; tmp; ) { |
8051 | struct sched_domain *parent = tmp->parent; |
8052 | if (!parent) |
8053 | break; |
8054 | |
8055 | if (sd_parent_degenerate(tmp, parent)) { |
8056 | tmp->parent = parent->parent; |
8057 | if (parent->parent) |
8058 | parent->parent->child = tmp; |
8059 | } else |
8060 | tmp = tmp->parent; |
8061 | } |
8062 | |
8063 | if (sd && sd_degenerate(sd)) { |
8064 | sd = sd->parent; |
8065 | if (sd) |
8066 | sd->child = NULL; |
8067 | } |
8068 | |
8069 | sched_domain_debug(sd, cpu); |
8070 | |
8071 | rq_attach_root(rq, rd); |
8072 | rcu_assign_pointer(rq->sd, sd); |
8073 | } |
8074 | |
8075 | /* cpus with isolated domains */ |
8076 | static cpumask_var_t cpu_isolated_map; |
8077 | |
8078 | /* Setup the mask of cpus configured for isolated domains */ |
8079 | static int __init isolated_cpu_setup(char *str) |
8080 | { |
8081 | alloc_bootmem_cpumask_var(&cpu_isolated_map); |
8082 | cpulist_parse(str, cpu_isolated_map); |
8083 | return 1; |
8084 | } |
8085 | |
8086 | __setup("isolcpus=", isolated_cpu_setup); |
8087 | |
8088 | /* |
8089 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
8090 | * to a function which identifies what group(along with sched group) a CPU |
8091 | * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids |
8092 | * (due to the fact that we keep track of groups covered with a struct cpumask). |
8093 | * |
8094 | * init_sched_build_groups will build a circular linked list of the groups |
8095 | * covered by the given span, and will set each group's ->cpumask correctly, |
8096 | * and ->cpu_power to 0. |
8097 | */ |
8098 | static void |
8099 | init_sched_build_groups(const struct cpumask *span, |
8100 | const struct cpumask *cpu_map, |
8101 | int (*group_fn)(int cpu, const struct cpumask *cpu_map, |
8102 | struct sched_group **sg, |
8103 | struct cpumask *tmpmask), |
8104 | struct cpumask *covered, struct cpumask *tmpmask) |
8105 | { |
8106 | struct sched_group *first = NULL, *last = NULL; |
8107 | int i; |
8108 | |
8109 | cpumask_clear(covered); |
8110 | |
8111 | for_each_cpu(i, span) { |
8112 | struct sched_group *sg; |
8113 | int group = group_fn(i, cpu_map, &sg, tmpmask); |
8114 | int j; |
8115 | |
8116 | if (cpumask_test_cpu(i, covered)) |
8117 | continue; |
8118 | |
8119 | cpumask_clear(sched_group_cpus(sg)); |
8120 | sg->cpu_power = 0; |
8121 | |
8122 | for_each_cpu(j, span) { |
8123 | if (group_fn(j, cpu_map, NULL, tmpmask) != group) |
8124 | continue; |
8125 | |
8126 | cpumask_set_cpu(j, covered); |
8127 | cpumask_set_cpu(j, sched_group_cpus(sg)); |
8128 | } |
8129 | if (!first) |
8130 | first = sg; |
8131 | if (last) |
8132 | last->next = sg; |
8133 | last = sg; |
8134 | } |
8135 | last->next = first; |
8136 | } |
8137 | |
8138 | #define SD_NODES_PER_DOMAIN 16 |
8139 | |
8140 | #ifdef CONFIG_NUMA |
8141 | |
8142 | /** |
8143 | * find_next_best_node - find the next node to include in a sched_domain |
8144 | * @node: node whose sched_domain we're building |
8145 | * @used_nodes: nodes already in the sched_domain |
8146 | * |
8147 | * Find the next node to include in a given scheduling domain. Simply |
8148 | * finds the closest node not already in the @used_nodes map. |
8149 | * |
8150 | * Should use nodemask_t. |
8151 | */ |
8152 | static int find_next_best_node(int node, nodemask_t *used_nodes) |
8153 | { |
8154 | int i, n, val, min_val, best_node = 0; |
8155 | |
8156 | min_val = INT_MAX; |
8157 | |
8158 | for (i = 0; i < nr_node_ids; i++) { |
8159 | /* Start at @node */ |
8160 | n = (node + i) % nr_node_ids; |
8161 | |
8162 | if (!nr_cpus_node(n)) |
8163 | continue; |
8164 | |
8165 | /* Skip already used nodes */ |
8166 | if (node_isset(n, *used_nodes)) |
8167 | continue; |
8168 | |
8169 | /* Simple min distance search */ |
8170 | val = node_distance(node, n); |
8171 | |
8172 | if (val < min_val) { |
8173 | min_val = val; |
8174 | best_node = n; |
8175 | } |
8176 | } |
8177 | |
8178 | node_set(best_node, *used_nodes); |
8179 | return best_node; |
8180 | } |
8181 | |
8182 | /** |
8183 | * sched_domain_node_span - get a cpumask for a node's sched_domain |
8184 | * @node: node whose cpumask we're constructing |
8185 | * @span: resulting cpumask |
8186 | * |
8187 | * Given a node, construct a good cpumask for its sched_domain to span. It |
8188 | * should be one that prevents unnecessary balancing, but also spreads tasks |
8189 | * out optimally. |
8190 | */ |
8191 | static void sched_domain_node_span(int node, struct cpumask *span) |
8192 | { |
8193 | nodemask_t used_nodes; |
8194 | int i; |
8195 | |
8196 | cpumask_clear(span); |
8197 | nodes_clear(used_nodes); |
8198 | |
8199 | cpumask_or(span, span, cpumask_of_node(node)); |
8200 | node_set(node, used_nodes); |
8201 | |
8202 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { |
8203 | int next_node = find_next_best_node(node, &used_nodes); |
8204 | |
8205 | cpumask_or(span, span, cpumask_of_node(next_node)); |
8206 | } |
8207 | } |
8208 | #endif /* CONFIG_NUMA */ |
8209 | |
8210 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
8211 | |
8212 | /* |
8213 | * The cpus mask in sched_group and sched_domain hangs off the end. |
8214 | * |
8215 | * ( See the the comments in include/linux/sched.h:struct sched_group |
8216 | * and struct sched_domain. ) |
8217 | */ |
8218 | struct static_sched_group { |
8219 | struct sched_group sg; |
8220 | DECLARE_BITMAP(cpus, CONFIG_NR_CPUS); |
8221 | }; |
8222 | |
8223 | struct static_sched_domain { |
8224 | struct sched_domain sd; |
8225 | DECLARE_BITMAP(span, CONFIG_NR_CPUS); |
8226 | }; |
8227 | |
8228 | struct s_data { |
8229 | #ifdef CONFIG_NUMA |
8230 | int sd_allnodes; |
8231 | cpumask_var_t domainspan; |
8232 | cpumask_var_t covered; |
8233 | cpumask_var_t notcovered; |
8234 | #endif |
8235 | cpumask_var_t nodemask; |
8236 | cpumask_var_t this_sibling_map; |
8237 | cpumask_var_t this_core_map; |
8238 | cpumask_var_t send_covered; |
8239 | cpumask_var_t tmpmask; |
8240 | struct sched_group **sched_group_nodes; |
8241 | struct root_domain *rd; |
8242 | }; |
8243 | |
8244 | enum s_alloc { |
8245 | sa_sched_groups = 0, |
8246 | sa_rootdomain, |
8247 | sa_tmpmask, |
8248 | sa_send_covered, |
8249 | sa_this_core_map, |
8250 | sa_this_sibling_map, |
8251 | sa_nodemask, |
8252 | sa_sched_group_nodes, |
8253 | #ifdef CONFIG_NUMA |
8254 | sa_notcovered, |
8255 | sa_covered, |
8256 | sa_domainspan, |
8257 | #endif |
8258 | sa_none, |
8259 | }; |
8260 | |
8261 | /* |
8262 | * SMT sched-domains: |
8263 | */ |
8264 | #ifdef CONFIG_SCHED_SMT |
8265 | static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains); |
8266 | static DEFINE_PER_CPU(struct static_sched_group, sched_group_cpus); |
8267 | |
8268 | static int |
8269 | cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map, |
8270 | struct sched_group **sg, struct cpumask *unused) |
8271 | { |
8272 | if (sg) |
8273 | *sg = &per_cpu(sched_group_cpus, cpu).sg; |
8274 | return cpu; |
8275 | } |
8276 | #endif /* CONFIG_SCHED_SMT */ |
8277 | |
8278 | /* |
8279 | * multi-core sched-domains: |
8280 | */ |
8281 | #ifdef CONFIG_SCHED_MC |
8282 | static DEFINE_PER_CPU(struct static_sched_domain, core_domains); |
8283 | static DEFINE_PER_CPU(struct static_sched_group, sched_group_core); |
8284 | #endif /* CONFIG_SCHED_MC */ |
8285 | |
8286 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) |
8287 | static int |
8288 | cpu_to_core_group(int cpu, const struct cpumask *cpu_map, |
8289 | struct sched_group **sg, struct cpumask *mask) |
8290 | { |
8291 | int group; |
8292 | |
8293 | cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); |
8294 | group = cpumask_first(mask); |
8295 | if (sg) |
8296 | *sg = &per_cpu(sched_group_core, group).sg; |
8297 | return group; |
8298 | } |
8299 | #elif defined(CONFIG_SCHED_MC) |
8300 | static int |
8301 | cpu_to_core_group(int cpu, const struct cpumask *cpu_map, |
8302 | struct sched_group **sg, struct cpumask *unused) |
8303 | { |
8304 | if (sg) |
8305 | *sg = &per_cpu(sched_group_core, cpu).sg; |
8306 | return cpu; |
8307 | } |
8308 | #endif |
8309 | |
8310 | static DEFINE_PER_CPU(struct static_sched_domain, phys_domains); |
8311 | static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys); |
8312 | |
8313 | static int |
8314 | cpu_to_phys_group(int cpu, const struct cpumask *cpu_map, |
8315 | struct sched_group **sg, struct cpumask *mask) |
8316 | { |
8317 | int group; |
8318 | #ifdef CONFIG_SCHED_MC |
8319 | cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map); |
8320 | group = cpumask_first(mask); |
8321 | #elif defined(CONFIG_SCHED_SMT) |
8322 | cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); |
8323 | group = cpumask_first(mask); |
8324 | #else |
8325 | group = cpu; |
8326 | #endif |
8327 | if (sg) |
8328 | *sg = &per_cpu(sched_group_phys, group).sg; |
8329 | return group; |
8330 | } |
8331 | |
8332 | #ifdef CONFIG_NUMA |
8333 | /* |
8334 | * The init_sched_build_groups can't handle what we want to do with node |
8335 | * groups, so roll our own. Now each node has its own list of groups which |
8336 | * gets dynamically allocated. |
8337 | */ |
8338 | static DEFINE_PER_CPU(struct static_sched_domain, node_domains); |
8339 | static struct sched_group ***sched_group_nodes_bycpu; |
8340 | |
8341 | static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains); |
8342 | static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes); |
8343 | |
8344 | static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map, |
8345 | struct sched_group **sg, |
8346 | struct cpumask *nodemask) |
8347 | { |
8348 | int group; |
8349 | |
8350 | cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map); |
8351 | group = cpumask_first(nodemask); |
8352 | |
8353 | if (sg) |
8354 | *sg = &per_cpu(sched_group_allnodes, group).sg; |
8355 | return group; |
8356 | } |
8357 | |
8358 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
8359 | { |
8360 | struct sched_group *sg = group_head; |
8361 | int j; |
8362 | |
8363 | if (!sg) |
8364 | return; |
8365 | do { |
8366 | for_each_cpu(j, sched_group_cpus(sg)) { |
8367 | struct sched_domain *sd; |
8368 | |
8369 | sd = &per_cpu(phys_domains, j).sd; |
8370 | if (j != group_first_cpu(sd->groups)) { |
8371 | /* |
8372 | * Only add "power" once for each |
8373 | * physical package. |
8374 | */ |
8375 | continue; |
8376 | } |
8377 | |
8378 | sg->cpu_power += sd->groups->cpu_power; |
8379 | } |
8380 | sg = sg->next; |
8381 | } while (sg != group_head); |
8382 | } |
8383 | |
8384 | static int build_numa_sched_groups(struct s_data *d, |
8385 | const struct cpumask *cpu_map, int num) |
8386 | { |
8387 | struct sched_domain *sd; |
8388 | struct sched_group *sg, *prev; |
8389 | int n, j; |
8390 | |
8391 | cpumask_clear(d->covered); |
8392 | cpumask_and(d->nodemask, cpumask_of_node(num), cpu_map); |
8393 | if (cpumask_empty(d->nodemask)) { |
8394 | d->sched_group_nodes[num] = NULL; |
8395 | goto out; |
8396 | } |
8397 | |
8398 | sched_domain_node_span(num, d->domainspan); |
8399 | cpumask_and(d->domainspan, d->domainspan, cpu_map); |
8400 | |
8401 | sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(), |
8402 | GFP_KERNEL, num); |
8403 | if (!sg) { |
8404 | printk(KERN_WARNING "Can not alloc domain group for node %d\n", |
8405 | num); |
8406 | return -ENOMEM; |
8407 | } |
8408 | d->sched_group_nodes[num] = sg; |
8409 | |
8410 | for_each_cpu(j, d->nodemask) { |
8411 | sd = &per_cpu(node_domains, j).sd; |
8412 | sd->groups = sg; |
8413 | } |
8414 | |
8415 | sg->cpu_power = 0; |
8416 | cpumask_copy(sched_group_cpus(sg), d->nodemask); |
8417 | sg->next = sg; |
8418 | cpumask_or(d->covered, d->covered, d->nodemask); |
8419 | |
8420 | prev = sg; |
8421 | for (j = 0; j < nr_node_ids; j++) { |
8422 | n = (num + j) % nr_node_ids; |
8423 | cpumask_complement(d->notcovered, d->covered); |
8424 | cpumask_and(d->tmpmask, d->notcovered, cpu_map); |
8425 | cpumask_and(d->tmpmask, d->tmpmask, d->domainspan); |
8426 | if (cpumask_empty(d->tmpmask)) |
8427 | break; |
8428 | cpumask_and(d->tmpmask, d->tmpmask, cpumask_of_node(n)); |
8429 | if (cpumask_empty(d->tmpmask)) |
8430 | continue; |
8431 | sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(), |
8432 | GFP_KERNEL, num); |
8433 | if (!sg) { |
8434 | printk(KERN_WARNING |
8435 | "Can not alloc domain group for node %d\n", j); |
8436 | return -ENOMEM; |
8437 | } |
8438 | sg->cpu_power = 0; |
8439 | cpumask_copy(sched_group_cpus(sg), d->tmpmask); |
8440 | sg->next = prev->next; |
8441 | cpumask_or(d->covered, d->covered, d->tmpmask); |
8442 | prev->next = sg; |
8443 | prev = sg; |
8444 | } |
8445 | out: |
8446 | return 0; |
8447 | } |
8448 | #endif /* CONFIG_NUMA */ |
8449 | |
8450 | #ifdef CONFIG_NUMA |
8451 | /* Free memory allocated for various sched_group structures */ |
8452 | static void free_sched_groups(const struct cpumask *cpu_map, |
8453 | struct cpumask *nodemask) |
8454 | { |
8455 | int cpu, i; |
8456 | |
8457 | for_each_cpu(cpu, cpu_map) { |
8458 | struct sched_group **sched_group_nodes |
8459 | = sched_group_nodes_bycpu[cpu]; |
8460 | |
8461 | if (!sched_group_nodes) |
8462 | continue; |
8463 | |
8464 | for (i = 0; i < nr_node_ids; i++) { |
8465 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; |
8466 | |
8467 | cpumask_and(nodemask, cpumask_of_node(i), cpu_map); |
8468 | if (cpumask_empty(nodemask)) |
8469 | continue; |
8470 | |
8471 | if (sg == NULL) |
8472 | continue; |
8473 | sg = sg->next; |
8474 | next_sg: |
8475 | oldsg = sg; |
8476 | sg = sg->next; |
8477 | kfree(oldsg); |
8478 | if (oldsg != sched_group_nodes[i]) |
8479 | goto next_sg; |
8480 | } |
8481 | kfree(sched_group_nodes); |
8482 | sched_group_nodes_bycpu[cpu] = NULL; |
8483 | } |
8484 | } |
8485 | #else /* !CONFIG_NUMA */ |
8486 | static void free_sched_groups(const struct cpumask *cpu_map, |
8487 | struct cpumask *nodemask) |
8488 | { |
8489 | } |
8490 | #endif /* CONFIG_NUMA */ |
8491 | |
8492 | /* |
8493 | * Initialize sched groups cpu_power. |
8494 | * |
8495 | * cpu_power indicates the capacity of sched group, which is used while |
8496 | * distributing the load between different sched groups in a sched domain. |
8497 | * Typically cpu_power for all the groups in a sched domain will be same unless |
8498 | * there are asymmetries in the topology. If there are asymmetries, group |
8499 | * having more cpu_power will pickup more load compared to the group having |
8500 | * less cpu_power. |
8501 | */ |
8502 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) |
8503 | { |
8504 | struct sched_domain *child; |
8505 | struct sched_group *group; |
8506 | long power; |
8507 | int weight; |
8508 | |
8509 | WARN_ON(!sd || !sd->groups); |
8510 | |
8511 | if (cpu != group_first_cpu(sd->groups)) |
8512 | return; |
8513 | |
8514 | child = sd->child; |
8515 | |
8516 | sd->groups->cpu_power = 0; |
8517 | |
8518 | if (!child) { |
8519 | power = SCHED_LOAD_SCALE; |
8520 | weight = cpumask_weight(sched_domain_span(sd)); |
8521 | /* |
8522 | * SMT siblings share the power of a single core. |
8523 | * Usually multiple threads get a better yield out of |
8524 | * that one core than a single thread would have, |
8525 | * reflect that in sd->smt_gain. |
8526 | */ |
8527 | if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { |
8528 | power *= sd->smt_gain; |
8529 | power /= weight; |
8530 | power >>= SCHED_LOAD_SHIFT; |
8531 | } |
8532 | sd->groups->cpu_power += power; |
8533 | return; |
8534 | } |
8535 | |
8536 | /* |
8537 | * Add cpu_power of each child group to this groups cpu_power. |
8538 | */ |
8539 | group = child->groups; |
8540 | do { |
8541 | sd->groups->cpu_power += group->cpu_power; |
8542 | group = group->next; |
8543 | } while (group != child->groups); |
8544 | } |
8545 | |
8546 | /* |
8547 | * Initializers for schedule domains |
8548 | * Non-inlined to reduce accumulated stack pressure in build_sched_domains() |
8549 | */ |
8550 | |
8551 | #ifdef CONFIG_SCHED_DEBUG |
8552 | # define SD_INIT_NAME(sd, type) sd->name = #type |
8553 | #else |
8554 | # define SD_INIT_NAME(sd, type) do { } while (0) |
8555 | #endif |
8556 | |
8557 | #define SD_INIT(sd, type) sd_init_##type(sd) |
8558 | |
8559 | #define SD_INIT_FUNC(type) \ |
8560 | static noinline void sd_init_##type(struct sched_domain *sd) \ |
8561 | { \ |
8562 | memset(sd, 0, sizeof(*sd)); \ |
8563 | *sd = SD_##type##_INIT; \ |
8564 | sd->level = SD_LV_##type; \ |
8565 | SD_INIT_NAME(sd, type); \ |
8566 | } |
8567 | |
8568 | SD_INIT_FUNC(CPU) |
8569 | #ifdef CONFIG_NUMA |
8570 | SD_INIT_FUNC(ALLNODES) |
8571 | SD_INIT_FUNC(NODE) |
8572 | #endif |
8573 | #ifdef CONFIG_SCHED_SMT |
8574 | SD_INIT_FUNC(SIBLING) |
8575 | #endif |
8576 | #ifdef CONFIG_SCHED_MC |
8577 | SD_INIT_FUNC(MC) |
8578 | #endif |
8579 | |
8580 | static int default_relax_domain_level = -1; |
8581 | |
8582 | static int __init setup_relax_domain_level(char *str) |
8583 | { |
8584 | unsigned long val; |
8585 | |
8586 | val = simple_strtoul(str, NULL, 0); |
8587 | if (val < SD_LV_MAX) |
8588 | default_relax_domain_level = val; |
8589 | |
8590 | return 1; |
8591 | } |
8592 | __setup("relax_domain_level=", setup_relax_domain_level); |
8593 | |
8594 | static void set_domain_attribute(struct sched_domain *sd, |
8595 | struct sched_domain_attr *attr) |
8596 | { |
8597 | int request; |
8598 | |
8599 | if (!attr || attr->relax_domain_level < 0) { |
8600 | if (default_relax_domain_level < 0) |
8601 | return; |
8602 | else |
8603 | request = default_relax_domain_level; |
8604 | } else |
8605 | request = attr->relax_domain_level; |
8606 | if (request < sd->level) { |
8607 | /* turn off idle balance on this domain */ |
8608 | sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
8609 | } else { |
8610 | /* turn on idle balance on this domain */ |
8611 | sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
8612 | } |
8613 | } |
8614 | |
8615 | static void __free_domain_allocs(struct s_data *d, enum s_alloc what, |
8616 | const struct cpumask *cpu_map) |
8617 | { |
8618 | switch (what) { |
8619 | case sa_sched_groups: |
8620 | free_sched_groups(cpu_map, d->tmpmask); /* fall through */ |
8621 | d->sched_group_nodes = NULL; |
8622 | case sa_rootdomain: |
8623 | free_rootdomain(d->rd); /* fall through */ |
8624 | case sa_tmpmask: |
8625 | free_cpumask_var(d->tmpmask); /* fall through */ |
8626 | case sa_send_covered: |
8627 | free_cpumask_var(d->send_covered); /* fall through */ |
8628 | case sa_this_core_map: |
8629 | free_cpumask_var(d->this_core_map); /* fall through */ |
8630 | case sa_this_sibling_map: |
8631 | free_cpumask_var(d->this_sibling_map); /* fall through */ |
8632 | case sa_nodemask: |
8633 | free_cpumask_var(d->nodemask); /* fall through */ |
8634 | case sa_sched_group_nodes: |
8635 | #ifdef CONFIG_NUMA |
8636 | kfree(d->sched_group_nodes); /* fall through */ |
8637 | case sa_notcovered: |
8638 | free_cpumask_var(d->notcovered); /* fall through */ |
8639 | case sa_covered: |
8640 | free_cpumask_var(d->covered); /* fall through */ |
8641 | case sa_domainspan: |
8642 | free_cpumask_var(d->domainspan); /* fall through */ |
8643 | #endif |
8644 | case sa_none: |
8645 | break; |
8646 | } |
8647 | } |
8648 | |
8649 | static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, |
8650 | const struct cpumask *cpu_map) |
8651 | { |
8652 | #ifdef CONFIG_NUMA |
8653 | if (!alloc_cpumask_var(&d->domainspan, GFP_KERNEL)) |
8654 | return sa_none; |
8655 | if (!alloc_cpumask_var(&d->covered, GFP_KERNEL)) |
8656 | return sa_domainspan; |
8657 | if (!alloc_cpumask_var(&d->notcovered, GFP_KERNEL)) |
8658 | return sa_covered; |
8659 | /* Allocate the per-node list of sched groups */ |
8660 | d->sched_group_nodes = kcalloc(nr_node_ids, |
8661 | sizeof(struct sched_group *), GFP_KERNEL); |
8662 | if (!d->sched_group_nodes) { |
8663 | printk(KERN_WARNING "Can not alloc sched group node list\n"); |
8664 | return sa_notcovered; |
8665 | } |
8666 | sched_group_nodes_bycpu[cpumask_first(cpu_map)] = d->sched_group_nodes; |
8667 | #endif |
8668 | if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL)) |
8669 | return sa_sched_group_nodes; |
8670 | if (!alloc_cpumask_var(&d->this_sibling_map, GFP_KERNEL)) |
8671 | return sa_nodemask; |
8672 | if (!alloc_cpumask_var(&d->this_core_map, GFP_KERNEL)) |
8673 | return sa_this_sibling_map; |
8674 | if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL)) |
8675 | return sa_this_core_map; |
8676 | if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL)) |
8677 | return sa_send_covered; |
8678 | d->rd = alloc_rootdomain(); |
8679 | if (!d->rd) { |
8680 | printk(KERN_WARNING "Cannot alloc root domain\n"); |
8681 | return sa_tmpmask; |
8682 | } |
8683 | return sa_rootdomain; |
8684 | } |
8685 | |
8686 | static struct sched_domain *__build_numa_sched_domains(struct s_data *d, |
8687 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, int i) |
8688 | { |
8689 | struct sched_domain *sd = NULL; |
8690 | #ifdef CONFIG_NUMA |
8691 | struct sched_domain *parent; |
8692 | |
8693 | d->sd_allnodes = 0; |
8694 | if (cpumask_weight(cpu_map) > |
8695 | SD_NODES_PER_DOMAIN * cpumask_weight(d->nodemask)) { |
8696 | sd = &per_cpu(allnodes_domains, i).sd; |
8697 | SD_INIT(sd, ALLNODES); |
8698 | set_domain_attribute(sd, attr); |
8699 | cpumask_copy(sched_domain_span(sd), cpu_map); |
8700 | cpu_to_allnodes_group(i, cpu_map, &sd->groups, d->tmpmask); |
8701 | d->sd_allnodes = 1; |
8702 | } |
8703 | parent = sd; |
8704 | |
8705 | sd = &per_cpu(node_domains, i).sd; |
8706 | SD_INIT(sd, NODE); |
8707 | set_domain_attribute(sd, attr); |
8708 | sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd)); |
8709 | sd->parent = parent; |
8710 | if (parent) |
8711 | parent->child = sd; |
8712 | cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map); |
8713 | #endif |
8714 | return sd; |
8715 | } |
8716 | |
8717 | static struct sched_domain *__build_cpu_sched_domain(struct s_data *d, |
8718 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
8719 | struct sched_domain *parent, int i) |
8720 | { |
8721 | struct sched_domain *sd; |
8722 | sd = &per_cpu(phys_domains, i).sd; |
8723 | SD_INIT(sd, CPU); |
8724 | set_domain_attribute(sd, attr); |
8725 | cpumask_copy(sched_domain_span(sd), d->nodemask); |
8726 | sd->parent = parent; |
8727 | if (parent) |
8728 | parent->child = sd; |
8729 | cpu_to_phys_group(i, cpu_map, &sd->groups, d->tmpmask); |
8730 | return sd; |
8731 | } |
8732 | |
8733 | static struct sched_domain *__build_mc_sched_domain(struct s_data *d, |
8734 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
8735 | struct sched_domain *parent, int i) |
8736 | { |
8737 | struct sched_domain *sd = parent; |
8738 | #ifdef CONFIG_SCHED_MC |
8739 | sd = &per_cpu(core_domains, i).sd; |
8740 | SD_INIT(sd, MC); |
8741 | set_domain_attribute(sd, attr); |
8742 | cpumask_and(sched_domain_span(sd), cpu_map, cpu_coregroup_mask(i)); |
8743 | sd->parent = parent; |
8744 | parent->child = sd; |
8745 | cpu_to_core_group(i, cpu_map, &sd->groups, d->tmpmask); |
8746 | #endif |
8747 | return sd; |
8748 | } |
8749 | |
8750 | static struct sched_domain *__build_smt_sched_domain(struct s_data *d, |
8751 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
8752 | struct sched_domain *parent, int i) |
8753 | { |
8754 | struct sched_domain *sd = parent; |
8755 | #ifdef CONFIG_SCHED_SMT |
8756 | sd = &per_cpu(cpu_domains, i).sd; |
8757 | SD_INIT(sd, SIBLING); |
8758 | set_domain_attribute(sd, attr); |
8759 | cpumask_and(sched_domain_span(sd), cpu_map, topology_thread_cpumask(i)); |
8760 | sd->parent = parent; |
8761 | parent->child = sd; |
8762 | cpu_to_cpu_group(i, cpu_map, &sd->groups, d->tmpmask); |
8763 | #endif |
8764 | return sd; |
8765 | } |
8766 | |
8767 | static void build_sched_groups(struct s_data *d, enum sched_domain_level l, |
8768 | const struct cpumask *cpu_map, int cpu) |
8769 | { |
8770 | switch (l) { |
8771 | #ifdef CONFIG_SCHED_SMT |
8772 | case SD_LV_SIBLING: /* set up CPU (sibling) groups */ |
8773 | cpumask_and(d->this_sibling_map, cpu_map, |
8774 | topology_thread_cpumask(cpu)); |
8775 | if (cpu == cpumask_first(d->this_sibling_map)) |
8776 | init_sched_build_groups(d->this_sibling_map, cpu_map, |
8777 | &cpu_to_cpu_group, |
8778 | d->send_covered, d->tmpmask); |
8779 | break; |
8780 | #endif |
8781 | #ifdef CONFIG_SCHED_MC |
8782 | case SD_LV_MC: /* set up multi-core groups */ |
8783 | cpumask_and(d->this_core_map, cpu_map, cpu_coregroup_mask(cpu)); |
8784 | if (cpu == cpumask_first(d->this_core_map)) |
8785 | init_sched_build_groups(d->this_core_map, cpu_map, |
8786 | &cpu_to_core_group, |
8787 | d->send_covered, d->tmpmask); |
8788 | break; |
8789 | #endif |
8790 | case SD_LV_CPU: /* set up physical groups */ |
8791 | cpumask_and(d->nodemask, cpumask_of_node(cpu), cpu_map); |
8792 | if (!cpumask_empty(d->nodemask)) |
8793 | init_sched_build_groups(d->nodemask, cpu_map, |
8794 | &cpu_to_phys_group, |
8795 | d->send_covered, d->tmpmask); |
8796 | break; |
8797 | #ifdef CONFIG_NUMA |
8798 | case SD_LV_ALLNODES: |
8799 | init_sched_build_groups(cpu_map, cpu_map, &cpu_to_allnodes_group, |
8800 | d->send_covered, d->tmpmask); |
8801 | break; |
8802 | #endif |
8803 | default: |
8804 | break; |
8805 | } |
8806 | } |
8807 | |
8808 | /* |
8809 | * Build sched domains for a given set of cpus and attach the sched domains |
8810 | * to the individual cpus |
8811 | */ |
8812 | static int __build_sched_domains(const struct cpumask *cpu_map, |
8813 | struct sched_domain_attr *attr) |
8814 | { |
8815 | enum s_alloc alloc_state = sa_none; |
8816 | struct s_data d; |
8817 | struct sched_domain *sd; |
8818 | int i; |
8819 | #ifdef CONFIG_NUMA |
8820 | d.sd_allnodes = 0; |
8821 | #endif |
8822 | |
8823 | alloc_state = __visit_domain_allocation_hell(&d, cpu_map); |
8824 | if (alloc_state != sa_rootdomain) |
8825 | goto error; |
8826 | alloc_state = sa_sched_groups; |
8827 | |
8828 | /* |
8829 | * Set up domains for cpus specified by the cpu_map. |
8830 | */ |
8831 | for_each_cpu(i, cpu_map) { |
8832 | cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)), |
8833 | cpu_map); |
8834 | |
8835 | sd = __build_numa_sched_domains(&d, cpu_map, attr, i); |
8836 | sd = __build_cpu_sched_domain(&d, cpu_map, attr, sd, i); |
8837 | sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i); |
8838 | sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i); |
8839 | } |
8840 | |
8841 | for_each_cpu(i, cpu_map) { |
8842 | build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i); |
8843 | build_sched_groups(&d, SD_LV_MC, cpu_map, i); |
8844 | } |
8845 | |
8846 | /* Set up physical groups */ |
8847 | for (i = 0; i < nr_node_ids; i++) |
8848 | build_sched_groups(&d, SD_LV_CPU, cpu_map, i); |
8849 | |
8850 | #ifdef CONFIG_NUMA |
8851 | /* Set up node groups */ |
8852 | if (d.sd_allnodes) |
8853 | build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, 0); |
8854 | |
8855 | for (i = 0; i < nr_node_ids; i++) |
8856 | if (build_numa_sched_groups(&d, cpu_map, i)) |
8857 | goto error; |
8858 | #endif |
8859 | |
8860 | /* Calculate CPU power for physical packages and nodes */ |
8861 | #ifdef CONFIG_SCHED_SMT |
8862 | for_each_cpu(i, cpu_map) { |
8863 | sd = &per_cpu(cpu_domains, i).sd; |
8864 | init_sched_groups_power(i, sd); |
8865 | } |
8866 | #endif |
8867 | #ifdef CONFIG_SCHED_MC |
8868 | for_each_cpu(i, cpu_map) { |
8869 | sd = &per_cpu(core_domains, i).sd; |
8870 | init_sched_groups_power(i, sd); |
8871 | } |
8872 | #endif |
8873 | |
8874 | for_each_cpu(i, cpu_map) { |
8875 | sd = &per_cpu(phys_domains, i).sd; |
8876 | init_sched_groups_power(i, sd); |
8877 | } |
8878 | |
8879 | #ifdef CONFIG_NUMA |
8880 | for (i = 0; i < nr_node_ids; i++) |
8881 | init_numa_sched_groups_power(d.sched_group_nodes[i]); |
8882 | |
8883 | if (d.sd_allnodes) { |
8884 | struct sched_group *sg; |
8885 | |
8886 | cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg, |
8887 | d.tmpmask); |
8888 | init_numa_sched_groups_power(sg); |
8889 | } |
8890 | #endif |
8891 | |
8892 | /* Attach the domains */ |
8893 | for_each_cpu(i, cpu_map) { |
8894 | #ifdef CONFIG_SCHED_SMT |
8895 | sd = &per_cpu(cpu_domains, i).sd; |
8896 | #elif defined(CONFIG_SCHED_MC) |
8897 | sd = &per_cpu(core_domains, i).sd; |
8898 | #else |
8899 | sd = &per_cpu(phys_domains, i).sd; |
8900 | #endif |
8901 | cpu_attach_domain(sd, d.rd, i); |
8902 | } |
8903 | |
8904 | d.sched_group_nodes = NULL; /* don't free this we still need it */ |
8905 | __free_domain_allocs(&d, sa_tmpmask, cpu_map); |
8906 | return 0; |
8907 | |
8908 | error: |
8909 | __free_domain_allocs(&d, alloc_state, cpu_map); |
8910 | return -ENOMEM; |
8911 | } |
8912 | |
8913 | static int build_sched_domains(const struct cpumask *cpu_map) |
8914 | { |
8915 | return __build_sched_domains(cpu_map, NULL); |
8916 | } |
8917 | |
8918 | static struct cpumask *doms_cur; /* current sched domains */ |
8919 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ |
8920 | static struct sched_domain_attr *dattr_cur; |
8921 | /* attribues of custom domains in 'doms_cur' */ |
8922 | |
8923 | /* |
8924 | * Special case: If a kmalloc of a doms_cur partition (array of |
8925 | * cpumask) fails, then fallback to a single sched domain, |
8926 | * as determined by the single cpumask fallback_doms. |
8927 | */ |
8928 | static cpumask_var_t fallback_doms; |
8929 | |
8930 | /* |
8931 | * arch_update_cpu_topology lets virtualized architectures update the |
8932 | * cpu core maps. It is supposed to return 1 if the topology changed |
8933 | * or 0 if it stayed the same. |
8934 | */ |
8935 | int __attribute__((weak)) arch_update_cpu_topology(void) |
8936 | { |
8937 | return 0; |
8938 | } |
8939 | |
8940 | /* |
8941 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
8942 | * For now this just excludes isolated cpus, but could be used to |
8943 | * exclude other special cases in the future. |
8944 | */ |
8945 | static int arch_init_sched_domains(const struct cpumask *cpu_map) |
8946 | { |
8947 | int err; |
8948 | |
8949 | arch_update_cpu_topology(); |
8950 | ndoms_cur = 1; |
8951 | doms_cur = kmalloc(cpumask_size(), GFP_KERNEL); |
8952 | if (!doms_cur) |
8953 | doms_cur = fallback_doms; |
8954 | cpumask_andnot(doms_cur, cpu_map, cpu_isolated_map); |
8955 | dattr_cur = NULL; |
8956 | err = build_sched_domains(doms_cur); |
8957 | register_sched_domain_sysctl(); |
8958 | |
8959 | return err; |
8960 | } |
8961 | |
8962 | static void arch_destroy_sched_domains(const struct cpumask *cpu_map, |
8963 | struct cpumask *tmpmask) |
8964 | { |
8965 | free_sched_groups(cpu_map, tmpmask); |
8966 | } |
8967 | |
8968 | /* |
8969 | * Detach sched domains from a group of cpus specified in cpu_map |
8970 | * These cpus will now be attached to the NULL domain |
8971 | */ |
8972 | static void detach_destroy_domains(const struct cpumask *cpu_map) |
8973 | { |
8974 | /* Save because hotplug lock held. */ |
8975 | static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS); |
8976 | int i; |
8977 | |
8978 | for_each_cpu(i, cpu_map) |
8979 | cpu_attach_domain(NULL, &def_root_domain, i); |
8980 | synchronize_sched(); |
8981 | arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask)); |
8982 | } |
8983 | |
8984 | /* handle null as "default" */ |
8985 | static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, |
8986 | struct sched_domain_attr *new, int idx_new) |
8987 | { |
8988 | struct sched_domain_attr tmp; |
8989 | |
8990 | /* fast path */ |
8991 | if (!new && !cur) |
8992 | return 1; |
8993 | |
8994 | tmp = SD_ATTR_INIT; |
8995 | return !memcmp(cur ? (cur + idx_cur) : &tmp, |
8996 | new ? (new + idx_new) : &tmp, |
8997 | sizeof(struct sched_domain_attr)); |
8998 | } |
8999 | |
9000 | /* |
9001 | * Partition sched domains as specified by the 'ndoms_new' |
9002 | * cpumasks in the array doms_new[] of cpumasks. This compares |
9003 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
9004 | * It destroys each deleted domain and builds each new domain. |
9005 | * |
9006 | * 'doms_new' is an array of cpumask's of length 'ndoms_new'. |
9007 | * The masks don't intersect (don't overlap.) We should setup one |
9008 | * sched domain for each mask. CPUs not in any of the cpumasks will |
9009 | * not be load balanced. If the same cpumask appears both in the |
9010 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
9011 | * it as it is. |
9012 | * |
9013 | * The passed in 'doms_new' should be kmalloc'd. This routine takes |
9014 | * ownership of it and will kfree it when done with it. If the caller |
9015 | * failed the kmalloc call, then it can pass in doms_new == NULL && |
9016 | * ndoms_new == 1, and partition_sched_domains() will fallback to |
9017 | * the single partition 'fallback_doms', it also forces the domains |
9018 | * to be rebuilt. |
9019 | * |
9020 | * If doms_new == NULL it will be replaced with cpu_online_mask. |
9021 | * ndoms_new == 0 is a special case for destroying existing domains, |
9022 | * and it will not create the default domain. |
9023 | * |
9024 | * Call with hotplug lock held |
9025 | */ |
9026 | /* FIXME: Change to struct cpumask *doms_new[] */ |
9027 | void partition_sched_domains(int ndoms_new, struct cpumask *doms_new, |
9028 | struct sched_domain_attr *dattr_new) |
9029 | { |
9030 | int i, j, n; |
9031 | int new_topology; |
9032 | |
9033 | mutex_lock(&sched_domains_mutex); |
9034 | |
9035 | /* always unregister in case we don't destroy any domains */ |
9036 | unregister_sched_domain_sysctl(); |
9037 | |
9038 | /* Let architecture update cpu core mappings. */ |
9039 | new_topology = arch_update_cpu_topology(); |
9040 | |
9041 | n = doms_new ? ndoms_new : 0; |
9042 | |
9043 | /* Destroy deleted domains */ |
9044 | for (i = 0; i < ndoms_cur; i++) { |
9045 | for (j = 0; j < n && !new_topology; j++) { |
9046 | if (cpumask_equal(&doms_cur[i], &doms_new[j]) |
9047 | && dattrs_equal(dattr_cur, i, dattr_new, j)) |
9048 | goto match1; |
9049 | } |
9050 | /* no match - a current sched domain not in new doms_new[] */ |
9051 | detach_destroy_domains(doms_cur + i); |
9052 | match1: |
9053 | ; |
9054 | } |
9055 | |
9056 | if (doms_new == NULL) { |
9057 | ndoms_cur = 0; |
9058 | doms_new = fallback_doms; |
9059 | cpumask_andnot(&doms_new[0], cpu_active_mask, cpu_isolated_map); |
9060 | WARN_ON_ONCE(dattr_new); |
9061 | } |
9062 | |
9063 | /* Build new domains */ |
9064 | for (i = 0; i < ndoms_new; i++) { |
9065 | for (j = 0; j < ndoms_cur && !new_topology; j++) { |
9066 | if (cpumask_equal(&doms_new[i], &doms_cur[j]) |
9067 | && dattrs_equal(dattr_new, i, dattr_cur, j)) |
9068 | goto match2; |
9069 | } |
9070 | /* no match - add a new doms_new */ |
9071 | __build_sched_domains(doms_new + i, |
9072 | dattr_new ? dattr_new + i : NULL); |
9073 | match2: |
9074 | ; |
9075 | } |
9076 | |
9077 | /* Remember the new sched domains */ |
9078 | if (doms_cur != fallback_doms) |
9079 | kfree(doms_cur); |
9080 | kfree(dattr_cur); /* kfree(NULL) is safe */ |
9081 | doms_cur = doms_new; |
9082 | dattr_cur = dattr_new; |
9083 | ndoms_cur = ndoms_new; |
9084 | |
9085 | register_sched_domain_sysctl(); |
9086 | |
9087 | mutex_unlock(&sched_domains_mutex); |
9088 | } |
9089 | |
9090 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
9091 | static void arch_reinit_sched_domains(void) |
9092 | { |
9093 | get_online_cpus(); |
9094 | |
9095 | /* Destroy domains first to force the rebuild */ |
9096 | partition_sched_domains(0, NULL, NULL); |
9097 | |
9098 | rebuild_sched_domains(); |
9099 | put_online_cpus(); |
9100 | } |
9101 | |
9102 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) |
9103 | { |
9104 | unsigned int level = 0; |
9105 | |
9106 | if (sscanf(buf, "%u", &level) != 1) |
9107 | return -EINVAL; |
9108 | |
9109 | /* |
9110 | * level is always be positive so don't check for |
9111 | * level < POWERSAVINGS_BALANCE_NONE which is 0 |
9112 | * What happens on 0 or 1 byte write, |
9113 | * need to check for count as well? |
9114 | */ |
9115 | |
9116 | if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS) |
9117 | return -EINVAL; |
9118 | |
9119 | if (smt) |
9120 | sched_smt_power_savings = level; |
9121 | else |
9122 | sched_mc_power_savings = level; |
9123 | |
9124 | arch_reinit_sched_domains(); |
9125 | |
9126 | return count; |
9127 | } |
9128 | |
9129 | #ifdef CONFIG_SCHED_MC |
9130 | static ssize_t sched_mc_power_savings_show(struct sysdev_class *class, |
9131 | char *page) |
9132 | { |
9133 | return sprintf(page, "%u\n", sched_mc_power_savings); |
9134 | } |
9135 | static ssize_t sched_mc_power_savings_store(struct sysdev_class *class, |
9136 | const char *buf, size_t count) |
9137 | { |
9138 | return sched_power_savings_store(buf, count, 0); |
9139 | } |
9140 | static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644, |
9141 | sched_mc_power_savings_show, |
9142 | sched_mc_power_savings_store); |
9143 | #endif |
9144 | |
9145 | #ifdef CONFIG_SCHED_SMT |
9146 | static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev, |
9147 | char *page) |
9148 | { |
9149 | return sprintf(page, "%u\n", sched_smt_power_savings); |
9150 | } |
9151 | static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev, |
9152 | const char *buf, size_t count) |
9153 | { |
9154 | return sched_power_savings_store(buf, count, 1); |
9155 | } |
9156 | static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644, |
9157 | sched_smt_power_savings_show, |
9158 | sched_smt_power_savings_store); |
9159 | #endif |
9160 | |
9161 | int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) |
9162 | { |
9163 | int err = 0; |
9164 | |
9165 | #ifdef CONFIG_SCHED_SMT |
9166 | if (smt_capable()) |
9167 | err = sysfs_create_file(&cls->kset.kobj, |
9168 | &attr_sched_smt_power_savings.attr); |
9169 | #endif |
9170 | #ifdef CONFIG_SCHED_MC |
9171 | if (!err && mc_capable()) |
9172 | err = sysfs_create_file(&cls->kset.kobj, |
9173 | &attr_sched_mc_power_savings.attr); |
9174 | #endif |
9175 | return err; |
9176 | } |
9177 | #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ |
9178 | |
9179 | #ifndef CONFIG_CPUSETS |
9180 | /* |
9181 | * Add online and remove offline CPUs from the scheduler domains. |
9182 | * When cpusets are enabled they take over this function. |
9183 | */ |
9184 | static int update_sched_domains(struct notifier_block *nfb, |
9185 | unsigned long action, void *hcpu) |
9186 | { |
9187 | switch (action) { |
9188 | case CPU_ONLINE: |
9189 | case CPU_ONLINE_FROZEN: |
9190 | case CPU_DOWN_PREPARE: |
9191 | case CPU_DOWN_PREPARE_FROZEN: |
9192 | case CPU_DOWN_FAILED: |
9193 | case CPU_DOWN_FAILED_FROZEN: |
9194 | partition_sched_domains(1, NULL, NULL); |
9195 | return NOTIFY_OK; |
9196 | |
9197 | default: |
9198 | return NOTIFY_DONE; |
9199 | } |
9200 | } |
9201 | #endif |
9202 | |
9203 | static int update_runtime(struct notifier_block *nfb, |
9204 | unsigned long action, void *hcpu) |
9205 | { |
9206 | int cpu = (int)(long)hcpu; |
9207 | |
9208 | switch (action) { |
9209 | case CPU_DOWN_PREPARE: |
9210 | case CPU_DOWN_PREPARE_FROZEN: |
9211 | disable_runtime(cpu_rq(cpu)); |
9212 | return NOTIFY_OK; |
9213 | |
9214 | case CPU_DOWN_FAILED: |
9215 | case CPU_DOWN_FAILED_FROZEN: |
9216 | case CPU_ONLINE: |
9217 | case CPU_ONLINE_FROZEN: |
9218 | enable_runtime(cpu_rq(cpu)); |
9219 | return NOTIFY_OK; |
9220 | |
9221 | default: |
9222 | return NOTIFY_DONE; |
9223 | } |
9224 | } |
9225 | |
9226 | void __init sched_init_smp(void) |
9227 | { |
9228 | cpumask_var_t non_isolated_cpus; |
9229 | |
9230 | alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); |
9231 | alloc_cpumask_var(&fallback_doms, GFP_KERNEL); |
9232 | |
9233 | #if defined(CONFIG_NUMA) |
9234 | sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **), |
9235 | GFP_KERNEL); |
9236 | BUG_ON(sched_group_nodes_bycpu == NULL); |
9237 | #endif |
9238 | get_online_cpus(); |
9239 | mutex_lock(&sched_domains_mutex); |
9240 | arch_init_sched_domains(cpu_active_mask); |
9241 | cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); |
9242 | if (cpumask_empty(non_isolated_cpus)) |
9243 | cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); |
9244 | mutex_unlock(&sched_domains_mutex); |
9245 | put_online_cpus(); |
9246 | |
9247 | #ifndef CONFIG_CPUSETS |
9248 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
9249 | hotcpu_notifier(update_sched_domains, 0); |
9250 | #endif |
9251 | |
9252 | /* RT runtime code needs to handle some hotplug events */ |
9253 | hotcpu_notifier(update_runtime, 0); |
9254 | |
9255 | init_hrtick(); |
9256 | |
9257 | /* Move init over to a non-isolated CPU */ |
9258 | if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) |
9259 | BUG(); |
9260 | sched_init_granularity(); |
9261 | free_cpumask_var(non_isolated_cpus); |
9262 | |
9263 | init_sched_rt_class(); |
9264 | } |
9265 | #else |
9266 | void __init sched_init_smp(void) |
9267 | { |
9268 | sched_init_granularity(); |
9269 | } |
9270 | #endif /* CONFIG_SMP */ |
9271 | |
9272 | const_debug unsigned int sysctl_timer_migration = 1; |
9273 | |
9274 | int in_sched_functions(unsigned long addr) |
9275 | { |
9276 | return in_lock_functions(addr) || |
9277 | (addr >= (unsigned long)__sched_text_start |
9278 | && addr < (unsigned long)__sched_text_end); |
9279 | } |
9280 | |
9281 | static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
9282 | { |
9283 | cfs_rq->tasks_timeline = RB_ROOT; |
9284 | INIT_LIST_HEAD(&cfs_rq->tasks); |
9285 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9286 | cfs_rq->rq = rq; |
9287 | #endif |
9288 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
9289 | } |
9290 | |
9291 | static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq) |
9292 | { |
9293 | struct rt_prio_array *array; |
9294 | int i; |
9295 | |
9296 | array = &rt_rq->active; |
9297 | for (i = 0; i < MAX_RT_PRIO; i++) { |
9298 | INIT_LIST_HEAD(array->queue + i); |
9299 | __clear_bit(i, array->bitmap); |
9300 | } |
9301 | /* delimiter for bitsearch: */ |
9302 | __set_bit(MAX_RT_PRIO, array->bitmap); |
9303 | |
9304 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
9305 | rt_rq->highest_prio.curr = MAX_RT_PRIO; |
9306 | #ifdef CONFIG_SMP |
9307 | rt_rq->highest_prio.next = MAX_RT_PRIO; |
9308 | #endif |
9309 | #endif |
9310 | #ifdef CONFIG_SMP |
9311 | rt_rq->rt_nr_migratory = 0; |
9312 | rt_rq->overloaded = 0; |
9313 | plist_head_init(&rt_rq->pushable_tasks, &rq->lock); |
9314 | #endif |
9315 | |
9316 | rt_rq->rt_time = 0; |
9317 | rt_rq->rt_throttled = 0; |
9318 | rt_rq->rt_runtime = 0; |
9319 | spin_lock_init(&rt_rq->rt_runtime_lock); |
9320 | |
9321 | #ifdef CONFIG_RT_GROUP_SCHED |
9322 | rt_rq->rt_nr_boosted = 0; |
9323 | rt_rq->rq = rq; |
9324 | #endif |
9325 | } |
9326 | |
9327 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9328 | static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, |
9329 | struct sched_entity *se, int cpu, int add, |
9330 | struct sched_entity *parent) |
9331 | { |
9332 | struct rq *rq = cpu_rq(cpu); |
9333 | tg->cfs_rq[cpu] = cfs_rq; |
9334 | init_cfs_rq(cfs_rq, rq); |
9335 | cfs_rq->tg = tg; |
9336 | if (add) |
9337 | list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); |
9338 | |
9339 | tg->se[cpu] = se; |
9340 | /* se could be NULL for init_task_group */ |
9341 | if (!se) |
9342 | return; |
9343 | |
9344 | if (!parent) |
9345 | se->cfs_rq = &rq->cfs; |
9346 | else |
9347 | se->cfs_rq = parent->my_q; |
9348 | |
9349 | se->my_q = cfs_rq; |
9350 | se->load.weight = tg->shares; |
9351 | se->load.inv_weight = 0; |
9352 | se->parent = parent; |
9353 | } |
9354 | #endif |
9355 | |
9356 | #ifdef CONFIG_RT_GROUP_SCHED |
9357 | static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq, |
9358 | struct sched_rt_entity *rt_se, int cpu, int add, |
9359 | struct sched_rt_entity *parent) |
9360 | { |
9361 | struct rq *rq = cpu_rq(cpu); |
9362 | |
9363 | tg->rt_rq[cpu] = rt_rq; |
9364 | init_rt_rq(rt_rq, rq); |
9365 | rt_rq->tg = tg; |
9366 | rt_rq->rt_se = rt_se; |
9367 | rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime; |
9368 | if (add) |
9369 | list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list); |
9370 | |
9371 | tg->rt_se[cpu] = rt_se; |
9372 | if (!rt_se) |
9373 | return; |
9374 | |
9375 | if (!parent) |
9376 | rt_se->rt_rq = &rq->rt; |
9377 | else |
9378 | rt_se->rt_rq = parent->my_q; |
9379 | |
9380 | rt_se->my_q = rt_rq; |
9381 | rt_se->parent = parent; |
9382 | INIT_LIST_HEAD(&rt_se->run_list); |
9383 | } |
9384 | #endif |
9385 | |
9386 | void __init sched_init(void) |
9387 | { |
9388 | int i, j; |
9389 | unsigned long alloc_size = 0, ptr; |
9390 | |
9391 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9392 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); |
9393 | #endif |
9394 | #ifdef CONFIG_RT_GROUP_SCHED |
9395 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); |
9396 | #endif |
9397 | #ifdef CONFIG_USER_SCHED |
9398 | alloc_size *= 2; |
9399 | #endif |
9400 | #ifdef CONFIG_CPUMASK_OFFSTACK |
9401 | alloc_size += num_possible_cpus() * cpumask_size(); |
9402 | #endif |
9403 | /* |
9404 | * As sched_init() is called before page_alloc is setup, |
9405 | * we use alloc_bootmem(). |
9406 | */ |
9407 | if (alloc_size) { |
9408 | ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); |
9409 | |
9410 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9411 | init_task_group.se = (struct sched_entity **)ptr; |
9412 | ptr += nr_cpu_ids * sizeof(void **); |
9413 | |
9414 | init_task_group.cfs_rq = (struct cfs_rq **)ptr; |
9415 | ptr += nr_cpu_ids * sizeof(void **); |
9416 | |
9417 | #ifdef CONFIG_USER_SCHED |
9418 | root_task_group.se = (struct sched_entity **)ptr; |
9419 | ptr += nr_cpu_ids * sizeof(void **); |
9420 | |
9421 | root_task_group.cfs_rq = (struct cfs_rq **)ptr; |
9422 | ptr += nr_cpu_ids * sizeof(void **); |
9423 | #endif /* CONFIG_USER_SCHED */ |
9424 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
9425 | #ifdef CONFIG_RT_GROUP_SCHED |
9426 | init_task_group.rt_se = (struct sched_rt_entity **)ptr; |
9427 | ptr += nr_cpu_ids * sizeof(void **); |
9428 | |
9429 | init_task_group.rt_rq = (struct rt_rq **)ptr; |
9430 | ptr += nr_cpu_ids * sizeof(void **); |
9431 | |
9432 | #ifdef CONFIG_USER_SCHED |
9433 | root_task_group.rt_se = (struct sched_rt_entity **)ptr; |
9434 | ptr += nr_cpu_ids * sizeof(void **); |
9435 | |
9436 | root_task_group.rt_rq = (struct rt_rq **)ptr; |
9437 | ptr += nr_cpu_ids * sizeof(void **); |
9438 | #endif /* CONFIG_USER_SCHED */ |
9439 | #endif /* CONFIG_RT_GROUP_SCHED */ |
9440 | #ifdef CONFIG_CPUMASK_OFFSTACK |
9441 | for_each_possible_cpu(i) { |
9442 | per_cpu(load_balance_tmpmask, i) = (void *)ptr; |
9443 | ptr += cpumask_size(); |
9444 | } |
9445 | #endif /* CONFIG_CPUMASK_OFFSTACK */ |
9446 | } |
9447 | |
9448 | #ifdef CONFIG_SMP |
9449 | init_defrootdomain(); |
9450 | #endif |
9451 | |
9452 | init_rt_bandwidth(&def_rt_bandwidth, |
9453 | global_rt_period(), global_rt_runtime()); |
9454 | |
9455 | #ifdef CONFIG_RT_GROUP_SCHED |
9456 | init_rt_bandwidth(&init_task_group.rt_bandwidth, |
9457 | global_rt_period(), global_rt_runtime()); |
9458 | #ifdef CONFIG_USER_SCHED |
9459 | init_rt_bandwidth(&root_task_group.rt_bandwidth, |
9460 | global_rt_period(), RUNTIME_INF); |
9461 | #endif /* CONFIG_USER_SCHED */ |
9462 | #endif /* CONFIG_RT_GROUP_SCHED */ |
9463 | |
9464 | #ifdef CONFIG_GROUP_SCHED |
9465 | list_add(&init_task_group.list, &task_groups); |
9466 | INIT_LIST_HEAD(&init_task_group.children); |
9467 | |
9468 | #ifdef CONFIG_USER_SCHED |
9469 | INIT_LIST_HEAD(&root_task_group.children); |
9470 | init_task_group.parent = &root_task_group; |
9471 | list_add(&init_task_group.siblings, &root_task_group.children); |
9472 | #endif /* CONFIG_USER_SCHED */ |
9473 | #endif /* CONFIG_GROUP_SCHED */ |
9474 | |
9475 | #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP |
9476 | update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long), |
9477 | __alignof__(unsigned long)); |
9478 | #endif |
9479 | for_each_possible_cpu(i) { |
9480 | struct rq *rq; |
9481 | |
9482 | rq = cpu_rq(i); |
9483 | spin_lock_init(&rq->lock); |
9484 | rq->nr_running = 0; |
9485 | rq->calc_load_active = 0; |
9486 | rq->calc_load_update = jiffies + LOAD_FREQ; |
9487 | init_cfs_rq(&rq->cfs, rq); |
9488 | init_rt_rq(&rq->rt, rq); |
9489 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9490 | init_task_group.shares = init_task_group_load; |
9491 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); |
9492 | #ifdef CONFIG_CGROUP_SCHED |
9493 | /* |
9494 | * How much cpu bandwidth does init_task_group get? |
9495 | * |
9496 | * In case of task-groups formed thr' the cgroup filesystem, it |
9497 | * gets 100% of the cpu resources in the system. This overall |
9498 | * system cpu resource is divided among the tasks of |
9499 | * init_task_group and its child task-groups in a fair manner, |
9500 | * based on each entity's (task or task-group's) weight |
9501 | * (se->load.weight). |
9502 | * |
9503 | * In other words, if init_task_group has 10 tasks of weight |
9504 | * 1024) and two child groups A0 and A1 (of weight 1024 each), |
9505 | * then A0's share of the cpu resource is: |
9506 | * |
9507 | * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% |
9508 | * |
9509 | * We achieve this by letting init_task_group's tasks sit |
9510 | * directly in rq->cfs (i.e init_task_group->se[] = NULL). |
9511 | */ |
9512 | init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL); |
9513 | #elif defined CONFIG_USER_SCHED |
9514 | root_task_group.shares = NICE_0_LOAD; |
9515 | init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL); |
9516 | /* |
9517 | * In case of task-groups formed thr' the user id of tasks, |
9518 | * init_task_group represents tasks belonging to root user. |
9519 | * Hence it forms a sibling of all subsequent groups formed. |
9520 | * In this case, init_task_group gets only a fraction of overall |
9521 | * system cpu resource, based on the weight assigned to root |
9522 | * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished |
9523 | * by letting tasks of init_task_group sit in a separate cfs_rq |
9524 | * (init_tg_cfs_rq) and having one entity represent this group of |
9525 | * tasks in rq->cfs (i.e init_task_group->se[] != NULL). |
9526 | */ |
9527 | init_tg_cfs_entry(&init_task_group, |
9528 | &per_cpu(init_tg_cfs_rq, i), |
9529 | &per_cpu(init_sched_entity, i), i, 1, |
9530 | root_task_group.se[i]); |
9531 | |
9532 | #endif |
9533 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
9534 | |
9535 | rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; |
9536 | #ifdef CONFIG_RT_GROUP_SCHED |
9537 | INIT_LIST_HEAD(&rq->leaf_rt_rq_list); |
9538 | #ifdef CONFIG_CGROUP_SCHED |
9539 | init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL); |
9540 | #elif defined CONFIG_USER_SCHED |
9541 | init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL); |
9542 | init_tg_rt_entry(&init_task_group, |
9543 | &per_cpu(init_rt_rq, i), |
9544 | &per_cpu(init_sched_rt_entity, i), i, 1, |
9545 | root_task_group.rt_se[i]); |
9546 | #endif |
9547 | #endif |
9548 | |
9549 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
9550 | rq->cpu_load[j] = 0; |
9551 | #ifdef CONFIG_SMP |
9552 | rq->sd = NULL; |
9553 | rq->rd = NULL; |
9554 | rq->post_schedule = 0; |
9555 | rq->active_balance = 0; |
9556 | rq->next_balance = jiffies; |
9557 | rq->push_cpu = 0; |
9558 | rq->cpu = i; |
9559 | rq->online = 0; |
9560 | rq->migration_thread = NULL; |
9561 | rq->idle_stamp = 0; |
9562 | rq->avg_idle = 2*sysctl_sched_migration_cost; |
9563 | INIT_LIST_HEAD(&rq->migration_queue); |
9564 | rq_attach_root(rq, &def_root_domain); |
9565 | #endif |
9566 | init_rq_hrtick(rq); |
9567 | atomic_set(&rq->nr_iowait, 0); |
9568 | } |
9569 | |
9570 | set_load_weight(&init_task); |
9571 | |
9572 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
9573 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); |
9574 | #endif |
9575 | |
9576 | #ifdef CONFIG_SMP |
9577 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); |
9578 | #endif |
9579 | |
9580 | #ifdef CONFIG_RT_MUTEXES |
9581 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); |
9582 | #endif |
9583 | |
9584 | /* |
9585 | * The boot idle thread does lazy MMU switching as well: |
9586 | */ |
9587 | atomic_inc(&init_mm.mm_count); |
9588 | enter_lazy_tlb(&init_mm, current); |
9589 | |
9590 | /* |
9591 | * Make us the idle thread. Technically, schedule() should not be |
9592 | * called from this thread, however somewhere below it might be, |
9593 | * but because we are the idle thread, we just pick up running again |
9594 | * when this runqueue becomes "idle". |
9595 | */ |
9596 | init_idle(current, smp_processor_id()); |
9597 | |
9598 | calc_load_update = jiffies + LOAD_FREQ; |
9599 | |
9600 | /* |
9601 | * During early bootup we pretend to be a normal task: |
9602 | */ |
9603 | current->sched_class = &fair_sched_class; |
9604 | |
9605 | /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */ |
9606 | zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT); |
9607 | #ifdef CONFIG_SMP |
9608 | #ifdef CONFIG_NO_HZ |
9609 | zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT); |
9610 | alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT); |
9611 | #endif |
9612 | /* May be allocated at isolcpus cmdline parse time */ |
9613 | if (cpu_isolated_map == NULL) |
9614 | zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); |
9615 | #endif /* SMP */ |
9616 | |
9617 | perf_event_init(); |
9618 | |
9619 | scheduler_running = 1; |
9620 | } |
9621 | |
9622 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
9623 | static inline int preempt_count_equals(int preempt_offset) |
9624 | { |
9625 | int nested = preempt_count() & ~PREEMPT_ACTIVE; |
9626 | |
9627 | return (nested == PREEMPT_INATOMIC_BASE + preempt_offset); |
9628 | } |
9629 | |
9630 | void __might_sleep(char *file, int line, int preempt_offset) |
9631 | { |
9632 | #ifdef in_atomic |
9633 | static unsigned long prev_jiffy; /* ratelimiting */ |
9634 | |
9635 | if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || |
9636 | system_state != SYSTEM_RUNNING || oops_in_progress) |
9637 | return; |
9638 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) |
9639 | return; |
9640 | prev_jiffy = jiffies; |
9641 | |
9642 | printk(KERN_ERR |
9643 | "BUG: sleeping function called from invalid context at %s:%d\n", |
9644 | file, line); |
9645 | printk(KERN_ERR |
9646 | "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", |
9647 | in_atomic(), irqs_disabled(), |
9648 | current->pid, current->comm); |
9649 | |
9650 | debug_show_held_locks(current); |
9651 | if (irqs_disabled()) |
9652 | print_irqtrace_events(current); |
9653 | dump_stack(); |
9654 | #endif |
9655 | } |
9656 | EXPORT_SYMBOL(__might_sleep); |
9657 | #endif |
9658 | |
9659 | #ifdef CONFIG_MAGIC_SYSRQ |
9660 | static void normalize_task(struct rq *rq, struct task_struct *p) |
9661 | { |
9662 | int on_rq; |
9663 | |
9664 | update_rq_clock(rq); |
9665 | on_rq = p->se.on_rq; |
9666 | if (on_rq) |
9667 | deactivate_task(rq, p, 0); |
9668 | __setscheduler(rq, p, SCHED_NORMAL, 0); |
9669 | if (on_rq) { |
9670 | activate_task(rq, p, 0); |
9671 | resched_task(rq->curr); |
9672 | } |
9673 | } |
9674 | |
9675 | void normalize_rt_tasks(void) |
9676 | { |
9677 | struct task_struct *g, *p; |
9678 | unsigned long flags; |
9679 | struct rq *rq; |
9680 | |
9681 | read_lock_irqsave(&tasklist_lock, flags); |
9682 | do_each_thread(g, p) { |
9683 | /* |
9684 | * Only normalize user tasks: |
9685 | */ |
9686 | if (!p->mm) |
9687 | continue; |
9688 | |
9689 | p->se.exec_start = 0; |
9690 | #ifdef CONFIG_SCHEDSTATS |
9691 | p->se.wait_start = 0; |
9692 | p->se.sleep_start = 0; |
9693 | p->se.block_start = 0; |
9694 | #endif |
9695 | |
9696 | if (!rt_task(p)) { |
9697 | /* |
9698 | * Renice negative nice level userspace |
9699 | * tasks back to 0: |
9700 | */ |
9701 | if (TASK_NICE(p) < 0 && p->mm) |
9702 | set_user_nice(p, 0); |
9703 | continue; |
9704 | } |
9705 | |
9706 | spin_lock(&p->pi_lock); |
9707 | rq = __task_rq_lock(p); |
9708 | |
9709 | normalize_task(rq, p); |
9710 | |
9711 | __task_rq_unlock(rq); |
9712 | spin_unlock(&p->pi_lock); |
9713 | } while_each_thread(g, p); |
9714 | |
9715 | read_unlock_irqrestore(&tasklist_lock, flags); |
9716 | } |
9717 | |
9718 | #endif /* CONFIG_MAGIC_SYSRQ */ |
9719 | |
9720 | #ifdef CONFIG_IA64 |
9721 | /* |
9722 | * These functions are only useful for the IA64 MCA handling. |
9723 | * |
9724 | * They can only be called when the whole system has been |
9725 | * stopped - every CPU needs to be quiescent, and no scheduling |
9726 | * activity can take place. Using them for anything else would |
9727 | * be a serious bug, and as a result, they aren't even visible |
9728 | * under any other configuration. |
9729 | */ |
9730 | |
9731 | /** |
9732 | * curr_task - return the current task for a given cpu. |
9733 | * @cpu: the processor in question. |
9734 | * |
9735 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
9736 | */ |
9737 | struct task_struct *curr_task(int cpu) |
9738 | { |
9739 | return cpu_curr(cpu); |
9740 | } |
9741 | |
9742 | /** |
9743 | * set_curr_task - set the current task for a given cpu. |
9744 | * @cpu: the processor in question. |
9745 | * @p: the task pointer to set. |
9746 | * |
9747 | * Description: This function must only be used when non-maskable interrupts |
9748 | * are serviced on a separate stack. It allows the architecture to switch the |
9749 | * notion of the current task on a cpu in a non-blocking manner. This function |
9750 | * must be called with all CPU's synchronized, and interrupts disabled, the |
9751 | * and caller must save the original value of the current task (see |
9752 | * curr_task() above) and restore that value before reenabling interrupts and |
9753 | * re-starting the system. |
9754 | * |
9755 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
9756 | */ |
9757 | void set_curr_task(int cpu, struct task_struct *p) |
9758 | { |
9759 | cpu_curr(cpu) = p; |
9760 | } |
9761 | |
9762 | #endif |
9763 | |
9764 | #ifdef CONFIG_FAIR_GROUP_SCHED |
9765 | static void free_fair_sched_group(struct task_group *tg) |
9766 | { |
9767 | int i; |
9768 | |
9769 | for_each_possible_cpu(i) { |
9770 | if (tg->cfs_rq) |
9771 | kfree(tg->cfs_rq[i]); |
9772 | if (tg->se) |
9773 | kfree(tg->se[i]); |
9774 | } |
9775 | |
9776 | kfree(tg->cfs_rq); |
9777 | kfree(tg->se); |
9778 | } |
9779 | |
9780 | static |
9781 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) |
9782 | { |
9783 | struct cfs_rq *cfs_rq; |
9784 | struct sched_entity *se; |
9785 | struct rq *rq; |
9786 | int i; |
9787 | |
9788 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL); |
9789 | if (!tg->cfs_rq) |
9790 | goto err; |
9791 | tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL); |
9792 | if (!tg->se) |
9793 | goto err; |
9794 | |
9795 | tg->shares = NICE_0_LOAD; |
9796 | |
9797 | for_each_possible_cpu(i) { |
9798 | rq = cpu_rq(i); |
9799 | |
9800 | cfs_rq = kzalloc_node(sizeof(struct cfs_rq), |
9801 | GFP_KERNEL, cpu_to_node(i)); |
9802 | if (!cfs_rq) |
9803 | goto err; |
9804 | |
9805 | se = kzalloc_node(sizeof(struct sched_entity), |
9806 | GFP_KERNEL, cpu_to_node(i)); |
9807 | if (!se) |
9808 | goto err; |
9809 | |
9810 | init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]); |
9811 | } |
9812 | |
9813 | return 1; |
9814 | |
9815 | err: |
9816 | return 0; |
9817 | } |
9818 | |
9819 | static inline void register_fair_sched_group(struct task_group *tg, int cpu) |
9820 | { |
9821 | list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list, |
9822 | &cpu_rq(cpu)->leaf_cfs_rq_list); |
9823 | } |
9824 | |
9825 | static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) |
9826 | { |
9827 | list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list); |
9828 | } |
9829 | #else /* !CONFG_FAIR_GROUP_SCHED */ |
9830 | static inline void free_fair_sched_group(struct task_group *tg) |
9831 | { |
9832 | } |
9833 | |
9834 | static inline |
9835 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) |
9836 | { |
9837 | return 1; |
9838 | } |
9839 | |
9840 | static inline void register_fair_sched_group(struct task_group *tg, int cpu) |
9841 | { |
9842 | } |
9843 | |
9844 | static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) |
9845 | { |
9846 | } |
9847 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
9848 | |
9849 | #ifdef CONFIG_RT_GROUP_SCHED |
9850 | static void free_rt_sched_group(struct task_group *tg) |
9851 | { |
9852 | int i; |
9853 | |
9854 | destroy_rt_bandwidth(&tg->rt_bandwidth); |
9855 | |
9856 | for_each_possible_cpu(i) { |
9857 | if (tg->rt_rq) |
9858 | kfree(tg->rt_rq[i]); |
9859 | if (tg->rt_se) |
9860 | kfree(tg->rt_se[i]); |
9861 | } |
9862 | |
9863 | kfree(tg->rt_rq); |
9864 | kfree(tg->rt_se); |
9865 | } |
9866 | |
9867 | static |
9868 | int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) |
9869 | { |
9870 | struct rt_rq *rt_rq; |
9871 | struct sched_rt_entity *rt_se; |
9872 | struct rq *rq; |
9873 | int i; |
9874 | |
9875 | tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL); |
9876 | if (!tg->rt_rq) |
9877 | goto err; |
9878 | tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL); |
9879 | if (!tg->rt_se) |
9880 | goto err; |
9881 | |
9882 | init_rt_bandwidth(&tg->rt_bandwidth, |
9883 | ktime_to_ns(def_rt_bandwidth.rt_period), 0); |
9884 | |
9885 | for_each_possible_cpu(i) { |
9886 | rq = cpu_rq(i); |
9887 | |
9888 | rt_rq = kzalloc_node(sizeof(struct rt_rq), |
9889 | GFP_KERNEL, cpu_to_node(i)); |
9890 | if (!rt_rq) |
9891 | goto err; |
9892 | |
9893 | rt_se = kzalloc_node(sizeof(struct sched_rt_entity), |
9894 | GFP_KERNEL, cpu_to_node(i)); |
9895 | if (!rt_se) |
9896 | goto err; |
9897 | |
9898 | init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]); |
9899 | } |
9900 | |
9901 | return 1; |
9902 | |
9903 | err: |
9904 | return 0; |
9905 | } |
9906 | |
9907 | static inline void register_rt_sched_group(struct task_group *tg, int cpu) |
9908 | { |
9909 | list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list, |
9910 | &cpu_rq(cpu)->leaf_rt_rq_list); |
9911 | } |
9912 | |
9913 | static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) |
9914 | { |
9915 | list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list); |
9916 | } |
9917 | #else /* !CONFIG_RT_GROUP_SCHED */ |
9918 | static inline void free_rt_sched_group(struct task_group *tg) |
9919 | { |
9920 | } |
9921 | |
9922 | static inline |
9923 | int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) |
9924 | { |
9925 | return 1; |
9926 | } |
9927 | |
9928 | static inline void register_rt_sched_group(struct task_group *tg, int cpu) |
9929 | { |
9930 | } |
9931 | |
9932 | static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) |
9933 | { |
9934 | } |
9935 | #endif /* CONFIG_RT_GROUP_SCHED */ |
9936 | |
9937 | #ifdef CONFIG_GROUP_SCHED |
9938 | static void free_sched_group(struct task_group *tg) |
9939 | { |
9940 | free_fair_sched_group(tg); |
9941 | free_rt_sched_group(tg); |
9942 | kfree(tg); |
9943 | } |
9944 | |
9945 | /* allocate runqueue etc for a new task group */ |
9946 | struct task_group *sched_create_group(struct task_group *parent) |
9947 | { |
9948 | struct task_group *tg; |
9949 | unsigned long flags; |
9950 | int i; |
9951 | |
9952 | tg = kzalloc(sizeof(*tg), GFP_KERNEL); |
9953 | if (!tg) |
9954 | return ERR_PTR(-ENOMEM); |
9955 | |
9956 | if (!alloc_fair_sched_group(tg, parent)) |
9957 | goto err; |
9958 | |
9959 | if (!alloc_rt_sched_group(tg, parent)) |
9960 | goto err; |
9961 | |
9962 | spin_lock_irqsave(&task_group_lock, flags); |
9963 | for_each_possible_cpu(i) { |
9964 | register_fair_sched_group(tg, i); |
9965 | register_rt_sched_group(tg, i); |
9966 | } |
9967 | list_add_rcu(&tg->list, &task_groups); |
9968 | |
9969 | WARN_ON(!parent); /* root should already exist */ |
9970 | |
9971 | tg->parent = parent; |
9972 | INIT_LIST_HEAD(&tg->children); |
9973 | list_add_rcu(&tg->siblings, &parent->children); |
9974 | spin_unlock_irqrestore(&task_group_lock, flags); |
9975 | |
9976 | return tg; |
9977 | |
9978 | err: |
9979 | free_sched_group(tg); |
9980 | return ERR_PTR(-ENOMEM); |
9981 | } |
9982 | |
9983 | /* rcu callback to free various structures associated with a task group */ |
9984 | static void free_sched_group_rcu(struct rcu_head *rhp) |
9985 | { |
9986 | /* now it should be safe to free those cfs_rqs */ |
9987 | free_sched_group(container_of(rhp, struct task_group, rcu)); |
9988 | } |
9989 | |
9990 | /* Destroy runqueue etc associated with a task group */ |
9991 | void sched_destroy_group(struct task_group *tg) |
9992 | { |
9993 | unsigned long flags; |
9994 | int i; |
9995 | |
9996 | spin_lock_irqsave(&task_group_lock, flags); |
9997 | for_each_possible_cpu(i) { |
9998 | unregister_fair_sched_group(tg, i); |
9999 | unregister_rt_sched_group(tg, i); |
10000 | } |
10001 | list_del_rcu(&tg->list); |
10002 | list_del_rcu(&tg->siblings); |
10003 | spin_unlock_irqrestore(&task_group_lock, flags); |
10004 | |
10005 | /* wait for possible concurrent references to cfs_rqs complete */ |
10006 | call_rcu(&tg->rcu, free_sched_group_rcu); |
10007 | } |
10008 | |
10009 | /* change task's runqueue when it moves between groups. |
10010 | * The caller of this function should have put the task in its new group |
10011 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to |
10012 | * reflect its new group. |
10013 | */ |
10014 | void sched_move_task(struct task_struct *tsk) |
10015 | { |
10016 | int on_rq, running; |
10017 | unsigned long flags; |
10018 | struct rq *rq; |
10019 | |
10020 | rq = task_rq_lock(tsk, &flags); |
10021 | |
10022 | update_rq_clock(rq); |
10023 | |
10024 | running = task_current(rq, tsk); |
10025 | on_rq = tsk->se.on_rq; |
10026 | |
10027 | if (on_rq) |
10028 | dequeue_task(rq, tsk, 0); |
10029 | if (unlikely(running)) |
10030 | tsk->sched_class->put_prev_task(rq, tsk); |
10031 | |
10032 | set_task_rq(tsk, task_cpu(tsk)); |
10033 | |
10034 | #ifdef CONFIG_FAIR_GROUP_SCHED |
10035 | if (tsk->sched_class->moved_group) |
10036 | tsk->sched_class->moved_group(tsk); |
10037 | #endif |
10038 | |
10039 | if (unlikely(running)) |
10040 | tsk->sched_class->set_curr_task(rq); |
10041 | if (on_rq) |
10042 | enqueue_task(rq, tsk, 0); |
10043 | |
10044 | task_rq_unlock(rq, &flags); |
10045 | } |
10046 | #endif /* CONFIG_GROUP_SCHED */ |
10047 | |
10048 | #ifdef CONFIG_FAIR_GROUP_SCHED |
10049 | static void __set_se_shares(struct sched_entity *se, unsigned long shares) |
10050 | { |
10051 | struct cfs_rq *cfs_rq = se->cfs_rq; |
10052 | int on_rq; |
10053 | |
10054 | on_rq = se->on_rq; |
10055 | if (on_rq) |
10056 | dequeue_entity(cfs_rq, se, 0); |
10057 | |
10058 | se->load.weight = shares; |
10059 | se->load.inv_weight = 0; |
10060 | |
10061 | if (on_rq) |
10062 | enqueue_entity(cfs_rq, se, 0); |
10063 | } |
10064 | |
10065 | static void set_se_shares(struct sched_entity *se, unsigned long shares) |
10066 | { |
10067 | struct cfs_rq *cfs_rq = se->cfs_rq; |
10068 | struct rq *rq = cfs_rq->rq; |
10069 | unsigned long flags; |
10070 | |
10071 | spin_lock_irqsave(&rq->lock, flags); |
10072 | __set_se_shares(se, shares); |
10073 | spin_unlock_irqrestore(&rq->lock, flags); |
10074 | } |
10075 | |
10076 | static DEFINE_MUTEX(shares_mutex); |
10077 | |
10078 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) |
10079 | { |
10080 | int i; |
10081 | unsigned long flags; |
10082 | |
10083 | /* |
10084 | * We can't change the weight of the root cgroup. |
10085 | */ |
10086 | if (!tg->se[0]) |
10087 | return -EINVAL; |
10088 | |
10089 | if (shares < MIN_SHARES) |
10090 | shares = MIN_SHARES; |
10091 | else if (shares > MAX_SHARES) |
10092 | shares = MAX_SHARES; |
10093 | |
10094 | mutex_lock(&shares_mutex); |
10095 | if (tg->shares == shares) |
10096 | goto done; |
10097 | |
10098 | spin_lock_irqsave(&task_group_lock, flags); |
10099 | for_each_possible_cpu(i) |
10100 | unregister_fair_sched_group(tg, i); |
10101 | list_del_rcu(&tg->siblings); |
10102 | spin_unlock_irqrestore(&task_group_lock, flags); |
10103 | |
10104 | /* wait for any ongoing reference to this group to finish */ |
10105 | synchronize_sched(); |
10106 | |
10107 | /* |
10108 | * Now we are free to modify the group's share on each cpu |
10109 | * w/o tripping rebalance_share or load_balance_fair. |
10110 | */ |
10111 | tg->shares = shares; |
10112 | for_each_possible_cpu(i) { |
10113 | /* |
10114 | * force a rebalance |
10115 | */ |
10116 | cfs_rq_set_shares(tg->cfs_rq[i], 0); |
10117 | set_se_shares(tg->se[i], shares); |
10118 | } |
10119 | |
10120 | /* |
10121 | * Enable load balance activity on this group, by inserting it back on |
10122 | * each cpu's rq->leaf_cfs_rq_list. |
10123 | */ |
10124 | spin_lock_irqsave(&task_group_lock, flags); |
10125 | for_each_possible_cpu(i) |
10126 | register_fair_sched_group(tg, i); |
10127 | list_add_rcu(&tg->siblings, &tg->parent->children); |
10128 | spin_unlock_irqrestore(&task_group_lock, flags); |
10129 | done: |
10130 | mutex_unlock(&shares_mutex); |
10131 | return 0; |
10132 | } |
10133 | |
10134 | unsigned long sched_group_shares(struct task_group *tg) |
10135 | { |
10136 | return tg->shares; |
10137 | } |
10138 | #endif |
10139 | |
10140 | #ifdef CONFIG_RT_GROUP_SCHED |
10141 | /* |
10142 | * Ensure that the real time constraints are schedulable. |
10143 | */ |
10144 | static DEFINE_MUTEX(rt_constraints_mutex); |
10145 | |
10146 | static unsigned long to_ratio(u64 period, u64 runtime) |
10147 | { |
10148 | if (runtime == RUNTIME_INF) |
10149 | return 1ULL << 20; |
10150 | |
10151 | return div64_u64(runtime << 20, period); |
10152 | } |
10153 | |
10154 | /* Must be called with tasklist_lock held */ |
10155 | static inline int tg_has_rt_tasks(struct task_group *tg) |
10156 | { |
10157 | struct task_struct *g, *p; |
10158 | |
10159 | do_each_thread(g, p) { |
10160 | if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg) |
10161 | return 1; |
10162 | } while_each_thread(g, p); |
10163 | |
10164 | return 0; |
10165 | } |
10166 | |
10167 | struct rt_schedulable_data { |
10168 | struct task_group *tg; |
10169 | u64 rt_period; |
10170 | u64 rt_runtime; |
10171 | }; |
10172 | |
10173 | static int tg_schedulable(struct task_group *tg, void *data) |
10174 | { |
10175 | struct rt_schedulable_data *d = data; |
10176 | struct task_group *child; |
10177 | unsigned long total, sum = 0; |
10178 | u64 period, runtime; |
10179 | |
10180 | period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
10181 | runtime = tg->rt_bandwidth.rt_runtime; |
10182 | |
10183 | if (tg == d->tg) { |
10184 | period = d->rt_period; |
10185 | runtime = d->rt_runtime; |
10186 | } |
10187 | |
10188 | #ifdef CONFIG_USER_SCHED |
10189 | if (tg == &root_task_group) { |
10190 | period = global_rt_period(); |
10191 | runtime = global_rt_runtime(); |
10192 | } |
10193 | #endif |
10194 | |
10195 | /* |
10196 | * Cannot have more runtime than the period. |
10197 | */ |
10198 | if (runtime > period && runtime != RUNTIME_INF) |
10199 | return -EINVAL; |
10200 | |
10201 | /* |
10202 | * Ensure we don't starve existing RT tasks. |
10203 | */ |
10204 | if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) |
10205 | return -EBUSY; |
10206 | |
10207 | total = to_ratio(period, runtime); |
10208 | |
10209 | /* |
10210 | * Nobody can have more than the global setting allows. |
10211 | */ |
10212 | if (total > to_ratio(global_rt_period(), global_rt_runtime())) |
10213 | return -EINVAL; |
10214 | |
10215 | /* |
10216 | * The sum of our children's runtime should not exceed our own. |
10217 | */ |
10218 | list_for_each_entry_rcu(child, &tg->children, siblings) { |
10219 | period = ktime_to_ns(child->rt_bandwidth.rt_period); |
10220 | runtime = child->rt_bandwidth.rt_runtime; |
10221 | |
10222 | if (child == d->tg) { |
10223 | period = d->rt_period; |
10224 | runtime = d->rt_runtime; |
10225 | } |
10226 | |
10227 | sum += to_ratio(period, runtime); |
10228 | } |
10229 | |
10230 | if (sum > total) |
10231 | return -EINVAL; |
10232 | |
10233 | return 0; |
10234 | } |
10235 | |
10236 | static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) |
10237 | { |
10238 | struct rt_schedulable_data data = { |
10239 | .tg = tg, |
10240 | .rt_period = period, |
10241 | .rt_runtime = runtime, |
10242 | }; |
10243 | |
10244 | return walk_tg_tree(tg_schedulable, tg_nop, &data); |
10245 | } |
10246 | |
10247 | static int tg_set_bandwidth(struct task_group *tg, |
10248 | u64 rt_period, u64 rt_runtime) |
10249 | { |
10250 | int i, err = 0; |
10251 | |
10252 | mutex_lock(&rt_constraints_mutex); |
10253 | read_lock(&tasklist_lock); |
10254 | err = __rt_schedulable(tg, rt_period, rt_runtime); |
10255 | if (err) |
10256 | goto unlock; |
10257 | |
10258 | spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
10259 | tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); |
10260 | tg->rt_bandwidth.rt_runtime = rt_runtime; |
10261 | |
10262 | for_each_possible_cpu(i) { |
10263 | struct rt_rq *rt_rq = tg->rt_rq[i]; |
10264 | |
10265 | spin_lock(&rt_rq->rt_runtime_lock); |
10266 | rt_rq->rt_runtime = rt_runtime; |
10267 | spin_unlock(&rt_rq->rt_runtime_lock); |
10268 | } |
10269 | spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
10270 | unlock: |
10271 | read_unlock(&tasklist_lock); |
10272 | mutex_unlock(&rt_constraints_mutex); |
10273 | |
10274 | return err; |
10275 | } |
10276 | |
10277 | int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) |
10278 | { |
10279 | u64 rt_runtime, rt_period; |
10280 | |
10281 | rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
10282 | rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; |
10283 | if (rt_runtime_us < 0) |
10284 | rt_runtime = RUNTIME_INF; |
10285 | |
10286 | return tg_set_bandwidth(tg, rt_period, rt_runtime); |
10287 | } |
10288 | |
10289 | long sched_group_rt_runtime(struct task_group *tg) |
10290 | { |
10291 | u64 rt_runtime_us; |
10292 | |
10293 | if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) |
10294 | return -1; |
10295 | |
10296 | rt_runtime_us = tg->rt_bandwidth.rt_runtime; |
10297 | do_div(rt_runtime_us, NSEC_PER_USEC); |
10298 | return rt_runtime_us; |
10299 | } |
10300 | |
10301 | int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) |
10302 | { |
10303 | u64 rt_runtime, rt_period; |
10304 | |
10305 | rt_period = (u64)rt_period_us * NSEC_PER_USEC; |
10306 | rt_runtime = tg->rt_bandwidth.rt_runtime; |
10307 | |
10308 | if (rt_period == 0) |
10309 | return -EINVAL; |
10310 | |
10311 | return tg_set_bandwidth(tg, rt_period, rt_runtime); |
10312 | } |
10313 | |
10314 | long sched_group_rt_period(struct task_group *tg) |
10315 | { |
10316 | u64 rt_period_us; |
10317 | |
10318 | rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); |
10319 | do_div(rt_period_us, NSEC_PER_USEC); |
10320 | return rt_period_us; |
10321 | } |
10322 | |
10323 | static int sched_rt_global_constraints(void) |
10324 | { |
10325 | u64 runtime, period; |
10326 | int ret = 0; |
10327 | |
10328 | if (sysctl_sched_rt_period <= 0) |
10329 | return -EINVAL; |
10330 | |
10331 | runtime = global_rt_runtime(); |
10332 | period = global_rt_period(); |
10333 | |
10334 | /* |
10335 | * Sanity check on the sysctl variables. |
10336 | */ |
10337 | if (runtime > period && runtime != RUNTIME_INF) |
10338 | return -EINVAL; |
10339 | |
10340 | mutex_lock(&rt_constraints_mutex); |
10341 | read_lock(&tasklist_lock); |
10342 | ret = __rt_schedulable(NULL, 0, 0); |
10343 | read_unlock(&tasklist_lock); |
10344 | mutex_unlock(&rt_constraints_mutex); |
10345 | |
10346 | return ret; |
10347 | } |
10348 | |
10349 | int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) |
10350 | { |
10351 | /* Don't accept realtime tasks when there is no way for them to run */ |
10352 | if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) |
10353 | return 0; |
10354 | |
10355 | return 1; |
10356 | } |
10357 | |
10358 | #else /* !CONFIG_RT_GROUP_SCHED */ |
10359 | static int sched_rt_global_constraints(void) |
10360 | { |
10361 | unsigned long flags; |
10362 | int i; |
10363 | |
10364 | if (sysctl_sched_rt_period <= 0) |
10365 | return -EINVAL; |
10366 | |
10367 | /* |
10368 | * There's always some RT tasks in the root group |
10369 | * -- migration, kstopmachine etc.. |
10370 | */ |
10371 | if (sysctl_sched_rt_runtime == 0) |
10372 | return -EBUSY; |
10373 | |
10374 | spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); |
10375 | for_each_possible_cpu(i) { |
10376 | struct rt_rq *rt_rq = &cpu_rq(i)->rt; |
10377 | |
10378 | spin_lock(&rt_rq->rt_runtime_lock); |
10379 | rt_rq->rt_runtime = global_rt_runtime(); |
10380 | spin_unlock(&rt_rq->rt_runtime_lock); |
10381 | } |
10382 | spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); |
10383 | |
10384 | return 0; |
10385 | } |
10386 | #endif /* CONFIG_RT_GROUP_SCHED */ |
10387 | |
10388 | int sched_rt_handler(struct ctl_table *table, int write, |
10389 | void __user *buffer, size_t *lenp, |
10390 | loff_t *ppos) |
10391 | { |
10392 | int ret; |
10393 | int old_period, old_runtime; |
10394 | static DEFINE_MUTEX(mutex); |
10395 | |
10396 | mutex_lock(&mutex); |
10397 | old_period = sysctl_sched_rt_period; |
10398 | old_runtime = sysctl_sched_rt_runtime; |
10399 | |
10400 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
10401 | |
10402 | if (!ret && write) { |
10403 | ret = sched_rt_global_constraints(); |
10404 | if (ret) { |
10405 | sysctl_sched_rt_period = old_period; |
10406 | sysctl_sched_rt_runtime = old_runtime; |
10407 | } else { |
10408 | def_rt_bandwidth.rt_runtime = global_rt_runtime(); |
10409 | def_rt_bandwidth.rt_period = |
10410 | ns_to_ktime(global_rt_period()); |
10411 | } |
10412 | } |
10413 | mutex_unlock(&mutex); |
10414 | |
10415 | return ret; |
10416 | } |
10417 | |
10418 | #ifdef CONFIG_CGROUP_SCHED |
10419 | |
10420 | /* return corresponding task_group object of a cgroup */ |
10421 | static inline struct task_group *cgroup_tg(struct cgroup *cgrp) |
10422 | { |
10423 | return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), |
10424 | struct task_group, css); |
10425 | } |
10426 | |
10427 | static struct cgroup_subsys_state * |
10428 | cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp) |
10429 | { |
10430 | struct task_group *tg, *parent; |
10431 | |
10432 | if (!cgrp->parent) { |
10433 | /* This is early initialization for the top cgroup */ |
10434 | return &init_task_group.css; |
10435 | } |
10436 | |
10437 | parent = cgroup_tg(cgrp->parent); |
10438 | tg = sched_create_group(parent); |
10439 | if (IS_ERR(tg)) |
10440 | return ERR_PTR(-ENOMEM); |
10441 | |
10442 | return &tg->css; |
10443 | } |
10444 | |
10445 | static void |
10446 | cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) |
10447 | { |
10448 | struct task_group *tg = cgroup_tg(cgrp); |
10449 | |
10450 | sched_destroy_group(tg); |
10451 | } |
10452 | |
10453 | static int |
10454 | cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk) |
10455 | { |
10456 | #ifdef CONFIG_RT_GROUP_SCHED |
10457 | if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk)) |
10458 | return -EINVAL; |
10459 | #else |
10460 | /* We don't support RT-tasks being in separate groups */ |
10461 | if (tsk->sched_class != &fair_sched_class) |
10462 | return -EINVAL; |
10463 | #endif |
10464 | return 0; |
10465 | } |
10466 | |
10467 | static int |
10468 | cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
10469 | struct task_struct *tsk, bool threadgroup) |
10470 | { |
10471 | int retval = cpu_cgroup_can_attach_task(cgrp, tsk); |
10472 | if (retval) |
10473 | return retval; |
10474 | if (threadgroup) { |
10475 | struct task_struct *c; |
10476 | rcu_read_lock(); |
10477 | list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) { |
10478 | retval = cpu_cgroup_can_attach_task(cgrp, c); |
10479 | if (retval) { |
10480 | rcu_read_unlock(); |
10481 | return retval; |
10482 | } |
10483 | } |
10484 | rcu_read_unlock(); |
10485 | } |
10486 | return 0; |
10487 | } |
10488 | |
10489 | static void |
10490 | cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
10491 | struct cgroup *old_cont, struct task_struct *tsk, |
10492 | bool threadgroup) |
10493 | { |
10494 | sched_move_task(tsk); |
10495 | if (threadgroup) { |
10496 | struct task_struct *c; |
10497 | rcu_read_lock(); |
10498 | list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) { |
10499 | sched_move_task(c); |
10500 | } |
10501 | rcu_read_unlock(); |
10502 | } |
10503 | } |
10504 | |
10505 | #ifdef CONFIG_FAIR_GROUP_SCHED |
10506 | static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype, |
10507 | u64 shareval) |
10508 | { |
10509 | return sched_group_set_shares(cgroup_tg(cgrp), shareval); |
10510 | } |
10511 | |
10512 | static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) |
10513 | { |
10514 | struct task_group *tg = cgroup_tg(cgrp); |
10515 | |
10516 | return (u64) tg->shares; |
10517 | } |
10518 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
10519 | |
10520 | #ifdef CONFIG_RT_GROUP_SCHED |
10521 | static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, |
10522 | s64 val) |
10523 | { |
10524 | return sched_group_set_rt_runtime(cgroup_tg(cgrp), val); |
10525 | } |
10526 | |
10527 | static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft) |
10528 | { |
10529 | return sched_group_rt_runtime(cgroup_tg(cgrp)); |
10530 | } |
10531 | |
10532 | static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype, |
10533 | u64 rt_period_us) |
10534 | { |
10535 | return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us); |
10536 | } |
10537 | |
10538 | static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) |
10539 | { |
10540 | return sched_group_rt_period(cgroup_tg(cgrp)); |
10541 | } |
10542 | #endif /* CONFIG_RT_GROUP_SCHED */ |
10543 | |
10544 | static struct cftype cpu_files[] = { |
10545 | #ifdef CONFIG_FAIR_GROUP_SCHED |
10546 | { |
10547 | .name = "shares", |
10548 | .read_u64 = cpu_shares_read_u64, |
10549 | .write_u64 = cpu_shares_write_u64, |
10550 | }, |
10551 | #endif |
10552 | #ifdef CONFIG_RT_GROUP_SCHED |
10553 | { |
10554 | .name = "rt_runtime_us", |
10555 | .read_s64 = cpu_rt_runtime_read, |
10556 | .write_s64 = cpu_rt_runtime_write, |
10557 | }, |
10558 | { |
10559 | .name = "rt_period_us", |
10560 | .read_u64 = cpu_rt_period_read_uint, |
10561 | .write_u64 = cpu_rt_period_write_uint, |
10562 | }, |
10563 | #endif |
10564 | }; |
10565 | |
10566 | static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) |
10567 | { |
10568 | return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); |
10569 | } |
10570 | |
10571 | struct cgroup_subsys cpu_cgroup_subsys = { |
10572 | .name = "cpu", |
10573 | .create = cpu_cgroup_create, |
10574 | .destroy = cpu_cgroup_destroy, |
10575 | .can_attach = cpu_cgroup_can_attach, |
10576 | .attach = cpu_cgroup_attach, |
10577 | .populate = cpu_cgroup_populate, |
10578 | .subsys_id = cpu_cgroup_subsys_id, |
10579 | .early_init = 1, |
10580 | }; |
10581 | |
10582 | #endif /* CONFIG_CGROUP_SCHED */ |
10583 | |
10584 | #ifdef CONFIG_CGROUP_CPUACCT |
10585 | |
10586 | /* |
10587 | * CPU accounting code for task groups. |
10588 | * |
10589 | * Based on the work by Paul Menage (menage@google.com) and Balbir Singh |
10590 | * (balbir@in.ibm.com). |
10591 | */ |
10592 | |
10593 | /* track cpu usage of a group of tasks and its child groups */ |
10594 | struct cpuacct { |
10595 | struct cgroup_subsys_state css; |
10596 | /* cpuusage holds pointer to a u64-type object on every cpu */ |
10597 | u64 *cpuusage; |
10598 | struct percpu_counter cpustat[CPUACCT_STAT_NSTATS]; |
10599 | struct cpuacct *parent; |
10600 | }; |
10601 | |
10602 | struct cgroup_subsys cpuacct_subsys; |
10603 | |
10604 | /* return cpu accounting group corresponding to this container */ |
10605 | static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp) |
10606 | { |
10607 | return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id), |
10608 | struct cpuacct, css); |
10609 | } |
10610 | |
10611 | /* return cpu accounting group to which this task belongs */ |
10612 | static inline struct cpuacct *task_ca(struct task_struct *tsk) |
10613 | { |
10614 | return container_of(task_subsys_state(tsk, cpuacct_subsys_id), |
10615 | struct cpuacct, css); |
10616 | } |
10617 | |
10618 | /* create a new cpu accounting group */ |
10619 | static struct cgroup_subsys_state *cpuacct_create( |
10620 | struct cgroup_subsys *ss, struct cgroup *cgrp) |
10621 | { |
10622 | struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL); |
10623 | int i; |
10624 | |
10625 | if (!ca) |
10626 | goto out; |
10627 | |
10628 | ca->cpuusage = alloc_percpu(u64); |
10629 | if (!ca->cpuusage) |
10630 | goto out_free_ca; |
10631 | |
10632 | for (i = 0; i < CPUACCT_STAT_NSTATS; i++) |
10633 | if (percpu_counter_init(&ca->cpustat[i], 0)) |
10634 | goto out_free_counters; |
10635 | |
10636 | if (cgrp->parent) |
10637 | ca->parent = cgroup_ca(cgrp->parent); |
10638 | |
10639 | return &ca->css; |
10640 | |
10641 | out_free_counters: |
10642 | while (--i >= 0) |
10643 | percpu_counter_destroy(&ca->cpustat[i]); |
10644 | free_percpu(ca->cpuusage); |
10645 | out_free_ca: |
10646 | kfree(ca); |
10647 | out: |
10648 | return ERR_PTR(-ENOMEM); |
10649 | } |
10650 | |
10651 | /* destroy an existing cpu accounting group */ |
10652 | static void |
10653 | cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) |
10654 | { |
10655 | struct cpuacct *ca = cgroup_ca(cgrp); |
10656 | int i; |
10657 | |
10658 | for (i = 0; i < CPUACCT_STAT_NSTATS; i++) |
10659 | percpu_counter_destroy(&ca->cpustat[i]); |
10660 | free_percpu(ca->cpuusage); |
10661 | kfree(ca); |
10662 | } |
10663 | |
10664 | static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu) |
10665 | { |
10666 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
10667 | u64 data; |
10668 | |
10669 | #ifndef CONFIG_64BIT |
10670 | /* |
10671 | * Take rq->lock to make 64-bit read safe on 32-bit platforms. |
10672 | */ |
10673 | spin_lock_irq(&cpu_rq(cpu)->lock); |
10674 | data = *cpuusage; |
10675 | spin_unlock_irq(&cpu_rq(cpu)->lock); |
10676 | #else |
10677 | data = *cpuusage; |
10678 | #endif |
10679 | |
10680 | return data; |
10681 | } |
10682 | |
10683 | static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) |
10684 | { |
10685 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
10686 | |
10687 | #ifndef CONFIG_64BIT |
10688 | /* |
10689 | * Take rq->lock to make 64-bit write safe on 32-bit platforms. |
10690 | */ |
10691 | spin_lock_irq(&cpu_rq(cpu)->lock); |
10692 | *cpuusage = val; |
10693 | spin_unlock_irq(&cpu_rq(cpu)->lock); |
10694 | #else |
10695 | *cpuusage = val; |
10696 | #endif |
10697 | } |
10698 | |
10699 | /* return total cpu usage (in nanoseconds) of a group */ |
10700 | static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft) |
10701 | { |
10702 | struct cpuacct *ca = cgroup_ca(cgrp); |
10703 | u64 totalcpuusage = 0; |
10704 | int i; |
10705 | |
10706 | for_each_present_cpu(i) |
10707 | totalcpuusage += cpuacct_cpuusage_read(ca, i); |
10708 | |
10709 | return totalcpuusage; |
10710 | } |
10711 | |
10712 | static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype, |
10713 | u64 reset) |
10714 | { |
10715 | struct cpuacct *ca = cgroup_ca(cgrp); |
10716 | int err = 0; |
10717 | int i; |
10718 | |
10719 | if (reset) { |
10720 | err = -EINVAL; |
10721 | goto out; |
10722 | } |
10723 | |
10724 | for_each_present_cpu(i) |
10725 | cpuacct_cpuusage_write(ca, i, 0); |
10726 | |
10727 | out: |
10728 | return err; |
10729 | } |
10730 | |
10731 | static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft, |
10732 | struct seq_file *m) |
10733 | { |
10734 | struct cpuacct *ca = cgroup_ca(cgroup); |
10735 | u64 percpu; |
10736 | int i; |
10737 | |
10738 | for_each_present_cpu(i) { |
10739 | percpu = cpuacct_cpuusage_read(ca, i); |
10740 | seq_printf(m, "%llu ", (unsigned long long) percpu); |
10741 | } |
10742 | seq_printf(m, "\n"); |
10743 | return 0; |
10744 | } |
10745 | |
10746 | static const char *cpuacct_stat_desc[] = { |
10747 | [CPUACCT_STAT_USER] = "user", |
10748 | [CPUACCT_STAT_SYSTEM] = "system", |
10749 | }; |
10750 | |
10751 | static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft, |
10752 | struct cgroup_map_cb *cb) |
10753 | { |
10754 | struct cpuacct *ca = cgroup_ca(cgrp); |
10755 | int i; |
10756 | |
10757 | for (i = 0; i < CPUACCT_STAT_NSTATS; i++) { |
10758 | s64 val = percpu_counter_read(&ca->cpustat[i]); |
10759 | val = cputime64_to_clock_t(val); |
10760 | cb->fill(cb, cpuacct_stat_desc[i], val); |
10761 | } |
10762 | return 0; |
10763 | } |
10764 | |
10765 | static struct cftype files[] = { |
10766 | { |
10767 | .name = "usage", |
10768 | .read_u64 = cpuusage_read, |
10769 | .write_u64 = cpuusage_write, |
10770 | }, |
10771 | { |
10772 | .name = "usage_percpu", |
10773 | .read_seq_string = cpuacct_percpu_seq_read, |
10774 | }, |
10775 | { |
10776 | .name = "stat", |
10777 | .read_map = cpuacct_stats_show, |
10778 | }, |
10779 | }; |
10780 | |
10781 | static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) |
10782 | { |
10783 | return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files)); |
10784 | } |
10785 | |
10786 | /* |
10787 | * charge this task's execution time to its accounting group. |
10788 | * |
10789 | * called with rq->lock held. |
10790 | */ |
10791 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime) |
10792 | { |
10793 | struct cpuacct *ca; |
10794 | int cpu; |
10795 | |
10796 | if (unlikely(!cpuacct_subsys.active)) |
10797 | return; |
10798 | |
10799 | cpu = task_cpu(tsk); |
10800 | |
10801 | rcu_read_lock(); |
10802 | |
10803 | ca = task_ca(tsk); |
10804 | |
10805 | for (; ca; ca = ca->parent) { |
10806 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
10807 | *cpuusage += cputime; |
10808 | } |
10809 | |
10810 | rcu_read_unlock(); |
10811 | } |
10812 | |
10813 | /* |
10814 | * Charge the system/user time to the task's accounting group. |
10815 | */ |
10816 | static void cpuacct_update_stats(struct task_struct *tsk, |
10817 | enum cpuacct_stat_index idx, cputime_t val) |
10818 | { |
10819 | struct cpuacct *ca; |
10820 | |
10821 | if (unlikely(!cpuacct_subsys.active)) |
10822 | return; |
10823 | |
10824 | rcu_read_lock(); |
10825 | ca = task_ca(tsk); |
10826 | |
10827 | do { |
10828 | percpu_counter_add(&ca->cpustat[idx], val); |
10829 | ca = ca->parent; |
10830 | } while (ca); |
10831 | rcu_read_unlock(); |
10832 | } |
10833 | |
10834 | struct cgroup_subsys cpuacct_subsys = { |
10835 | .name = "cpuacct", |
10836 | .create = cpuacct_create, |
10837 | .destroy = cpuacct_destroy, |
10838 | .populate = cpuacct_populate, |
10839 | .subsys_id = cpuacct_subsys_id, |
10840 | }; |
10841 | #endif /* CONFIG_CGROUP_CPUACCT */ |
10842 | |
10843 | #ifndef CONFIG_SMP |
10844 | |
10845 | int rcu_expedited_torture_stats(char *page) |
10846 | { |
10847 | return 0; |
10848 | } |
10849 | EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats); |
10850 | |
10851 | void synchronize_sched_expedited(void) |
10852 | { |
10853 | } |
10854 | EXPORT_SYMBOL_GPL(synchronize_sched_expedited); |
10855 | |
10856 | #else /* #ifndef CONFIG_SMP */ |
10857 | |
10858 | static DEFINE_PER_CPU(struct migration_req, rcu_migration_req); |
10859 | static DEFINE_MUTEX(rcu_sched_expedited_mutex); |
10860 | |
10861 | #define RCU_EXPEDITED_STATE_POST -2 |
10862 | #define RCU_EXPEDITED_STATE_IDLE -1 |
10863 | |
10864 | static int rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE; |
10865 | |
10866 | int rcu_expedited_torture_stats(char *page) |
10867 | { |
10868 | int cnt = 0; |
10869 | int cpu; |
10870 | |
10871 | cnt += sprintf(&page[cnt], "state: %d /", rcu_expedited_state); |
10872 | for_each_online_cpu(cpu) { |
10873 | cnt += sprintf(&page[cnt], " %d:%d", |
10874 | cpu, per_cpu(rcu_migration_req, cpu).dest_cpu); |
10875 | } |
10876 | cnt += sprintf(&page[cnt], "\n"); |
10877 | return cnt; |
10878 | } |
10879 | EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats); |
10880 | |
10881 | static long synchronize_sched_expedited_count; |
10882 | |
10883 | /* |
10884 | * Wait for an rcu-sched grace period to elapse, but use "big hammer" |
10885 | * approach to force grace period to end quickly. This consumes |
10886 | * significant time on all CPUs, and is thus not recommended for |
10887 | * any sort of common-case code. |
10888 | * |
10889 | * Note that it is illegal to call this function while holding any |
10890 | * lock that is acquired by a CPU-hotplug notifier. Failing to |
10891 | * observe this restriction will result in deadlock. |
10892 | */ |
10893 | void synchronize_sched_expedited(void) |
10894 | { |
10895 | int cpu; |
10896 | unsigned long flags; |
10897 | bool need_full_sync = 0; |
10898 | struct rq *rq; |
10899 | struct migration_req *req; |
10900 | long snap; |
10901 | int trycount = 0; |
10902 | |
10903 | smp_mb(); /* ensure prior mod happens before capturing snap. */ |
10904 | snap = ACCESS_ONCE(synchronize_sched_expedited_count) + 1; |
10905 | get_online_cpus(); |
10906 | while (!mutex_trylock(&rcu_sched_expedited_mutex)) { |
10907 | put_online_cpus(); |
10908 | if (trycount++ < 10) |
10909 | udelay(trycount * num_online_cpus()); |
10910 | else { |
10911 | synchronize_sched(); |
10912 | return; |
10913 | } |
10914 | if (ACCESS_ONCE(synchronize_sched_expedited_count) - snap > 0) { |
10915 | smp_mb(); /* ensure test happens before caller kfree */ |
10916 | return; |
10917 | } |
10918 | get_online_cpus(); |
10919 | } |
10920 | rcu_expedited_state = RCU_EXPEDITED_STATE_POST; |
10921 | for_each_online_cpu(cpu) { |
10922 | rq = cpu_rq(cpu); |
10923 | req = &per_cpu(rcu_migration_req, cpu); |
10924 | init_completion(&req->done); |
10925 | req->task = NULL; |
10926 | req->dest_cpu = RCU_MIGRATION_NEED_QS; |
10927 | spin_lock_irqsave(&rq->lock, flags); |
10928 | list_add(&req->list, &rq->migration_queue); |
10929 | spin_unlock_irqrestore(&rq->lock, flags); |
10930 | wake_up_process(rq->migration_thread); |
10931 | } |
10932 | for_each_online_cpu(cpu) { |
10933 | rcu_expedited_state = cpu; |
10934 | req = &per_cpu(rcu_migration_req, cpu); |
10935 | rq = cpu_rq(cpu); |
10936 | wait_for_completion(&req->done); |
10937 | spin_lock_irqsave(&rq->lock, flags); |
10938 | if (unlikely(req->dest_cpu == RCU_MIGRATION_MUST_SYNC)) |
10939 | need_full_sync = 1; |
10940 | req->dest_cpu = RCU_MIGRATION_IDLE; |
10941 | spin_unlock_irqrestore(&rq->lock, flags); |
10942 | } |
10943 | rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE; |
10944 | mutex_unlock(&rcu_sched_expedited_mutex); |
10945 | put_online_cpus(); |
10946 | if (need_full_sync) |
10947 | synchronize_sched(); |
10948 | } |
10949 | EXPORT_SYMBOL_GPL(synchronize_sched_expedited); |
10950 | |
10951 | #endif /* #else #ifndef CONFIG_SMP */ |
10952 |
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