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