Root/
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 | /* |
327 | * Strictly speaking this rcu_read_lock() is not needed since the |
328 | * task_group is tied to the cgroup, which in turn can never go away |
329 | * as long as there are tasks attached to it. |
330 | * |
331 | * However since task_group() uses task_subsys_state() which is an |
332 | * rcu_dereference() user, this quiets CONFIG_PROVE_RCU. |
333 | */ |
334 | rcu_read_lock(); |
335 | #ifdef CONFIG_FAIR_GROUP_SCHED |
336 | p->se.cfs_rq = task_group(p)->cfs_rq[cpu]; |
337 | p->se.parent = task_group(p)->se[cpu]; |
338 | #endif |
339 | |
340 | #ifdef CONFIG_RT_GROUP_SCHED |
341 | p->rt.rt_rq = task_group(p)->rt_rq[cpu]; |
342 | p->rt.parent = task_group(p)->rt_se[cpu]; |
343 | #endif |
344 | rcu_read_unlock(); |
345 | } |
346 | |
347 | #else |
348 | |
349 | static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { } |
350 | static inline struct task_group *task_group(struct task_struct *p) |
351 | { |
352 | return NULL; |
353 | } |
354 | |
355 | #endif /* CONFIG_CGROUP_SCHED */ |
356 | |
357 | /* CFS-related fields in a runqueue */ |
358 | struct cfs_rq { |
359 | struct load_weight load; |
360 | unsigned long nr_running; |
361 | |
362 | u64 exec_clock; |
363 | u64 min_vruntime; |
364 | |
365 | struct rb_root tasks_timeline; |
366 | struct rb_node *rb_leftmost; |
367 | |
368 | struct list_head tasks; |
369 | struct list_head *balance_iterator; |
370 | |
371 | /* |
372 | * 'curr' points to currently running entity on this cfs_rq. |
373 | * It is set to NULL otherwise (i.e when none are currently running). |
374 | */ |
375 | struct sched_entity *curr, *next, *last; |
376 | |
377 | unsigned int nr_spread_over; |
378 | |
379 | #ifdef CONFIG_FAIR_GROUP_SCHED |
380 | struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ |
381 | |
382 | /* |
383 | * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in |
384 | * a hierarchy). Non-leaf lrqs hold other higher schedulable entities |
385 | * (like users, containers etc.) |
386 | * |
387 | * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This |
388 | * list is used during load balance. |
389 | */ |
390 | struct list_head leaf_cfs_rq_list; |
391 | struct task_group *tg; /* group that "owns" this runqueue */ |
392 | |
393 | #ifdef CONFIG_SMP |
394 | /* |
395 | * the part of load.weight contributed by tasks |
396 | */ |
397 | unsigned long task_weight; |
398 | |
399 | /* |
400 | * h_load = weight * f(tg) |
401 | * |
402 | * Where f(tg) is the recursive weight fraction assigned to |
403 | * this group. |
404 | */ |
405 | unsigned long h_load; |
406 | |
407 | /* |
408 | * this cpu's part of tg->shares |
409 | */ |
410 | unsigned long shares; |
411 | |
412 | /* |
413 | * load.weight at the time we set shares |
414 | */ |
415 | unsigned long rq_weight; |
416 | #endif |
417 | #endif |
418 | }; |
419 | |
420 | /* Real-Time classes' related field in a runqueue: */ |
421 | struct rt_rq { |
422 | struct rt_prio_array active; |
423 | unsigned long rt_nr_running; |
424 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
425 | struct { |
426 | int curr; /* highest queued rt task prio */ |
427 | #ifdef CONFIG_SMP |
428 | int next; /* next highest */ |
429 | #endif |
430 | } highest_prio; |
431 | #endif |
432 | #ifdef CONFIG_SMP |
433 | unsigned long rt_nr_migratory; |
434 | unsigned long rt_nr_total; |
435 | int overloaded; |
436 | struct plist_head pushable_tasks; |
437 | #endif |
438 | int rt_throttled; |
439 | u64 rt_time; |
440 | u64 rt_runtime; |
441 | /* Nests inside the rq lock: */ |
442 | raw_spinlock_t rt_runtime_lock; |
443 | |
444 | #ifdef CONFIG_RT_GROUP_SCHED |
445 | unsigned long rt_nr_boosted; |
446 | |
447 | struct rq *rq; |
448 | struct list_head leaf_rt_rq_list; |
449 | struct task_group *tg; |
450 | #endif |
451 | }; |
452 | |
453 | #ifdef CONFIG_SMP |
454 | |
455 | /* |
456 | * We add the notion of a root-domain which will be used to define per-domain |
457 | * variables. Each exclusive cpuset essentially defines an island domain by |
458 | * fully partitioning the member cpus from any other cpuset. Whenever a new |
459 | * exclusive cpuset is created, we also create and attach a new root-domain |
460 | * object. |
461 | * |
462 | */ |
463 | struct root_domain { |
464 | atomic_t refcount; |
465 | cpumask_var_t span; |
466 | cpumask_var_t online; |
467 | |
468 | /* |
469 | * The "RT overload" flag: it gets set if a CPU has more than |
470 | * one runnable RT task. |
471 | */ |
472 | cpumask_var_t rto_mask; |
473 | atomic_t rto_count; |
474 | #ifdef CONFIG_SMP |
475 | struct cpupri cpupri; |
476 | #endif |
477 | }; |
478 | |
479 | /* |
480 | * By default the system creates a single root-domain with all cpus as |
481 | * members (mimicking the global state we have today). |
482 | */ |
483 | static struct root_domain def_root_domain; |
484 | |
485 | #endif |
486 | |
487 | /* |
488 | * This is the main, per-CPU runqueue data structure. |
489 | * |
490 | * Locking rule: those places that want to lock multiple runqueues |
491 | * (such as the load balancing or the thread migration code), lock |
492 | * acquire operations must be ordered by ascending &runqueue. |
493 | */ |
494 | struct rq { |
495 | /* runqueue lock: */ |
496 | raw_spinlock_t lock; |
497 | |
498 | /* |
499 | * nr_running and cpu_load should be in the same cacheline because |
500 | * remote CPUs use both these fields when doing load calculation. |
501 | */ |
502 | unsigned long nr_running; |
503 | #define CPU_LOAD_IDX_MAX 5 |
504 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; |
505 | #ifdef CONFIG_NO_HZ |
506 | unsigned char in_nohz_recently; |
507 | #endif |
508 | /* capture load from *all* tasks on this cpu: */ |
509 | struct load_weight load; |
510 | unsigned long nr_load_updates; |
511 | u64 nr_switches; |
512 | |
513 | struct cfs_rq cfs; |
514 | struct rt_rq rt; |
515 | |
516 | #ifdef CONFIG_FAIR_GROUP_SCHED |
517 | /* list of leaf cfs_rq on this cpu: */ |
518 | struct list_head leaf_cfs_rq_list; |
519 | #endif |
520 | #ifdef CONFIG_RT_GROUP_SCHED |
521 | struct list_head leaf_rt_rq_list; |
522 | #endif |
523 | |
524 | /* |
525 | * This is part of a global counter where only the total sum |
526 | * over all CPUs matters. A task can increase this counter on |
527 | * one CPU and if it got migrated afterwards it may decrease |
528 | * it on another CPU. Always updated under the runqueue lock: |
529 | */ |
530 | unsigned long nr_uninterruptible; |
531 | |
532 | struct task_struct *curr, *idle; |
533 | unsigned long next_balance; |
534 | struct mm_struct *prev_mm; |
535 | |
536 | u64 clock; |
537 | |
538 | atomic_t nr_iowait; |
539 | |
540 | #ifdef CONFIG_SMP |
541 | struct root_domain *rd; |
542 | struct sched_domain *sd; |
543 | |
544 | unsigned char idle_at_tick; |
545 | /* For active balancing */ |
546 | int post_schedule; |
547 | int active_balance; |
548 | int push_cpu; |
549 | /* cpu of this runqueue: */ |
550 | int cpu; |
551 | int online; |
552 | |
553 | unsigned long avg_load_per_task; |
554 | |
555 | struct task_struct *migration_thread; |
556 | struct list_head migration_queue; |
557 | |
558 | u64 rt_avg; |
559 | u64 age_stamp; |
560 | u64 idle_stamp; |
561 | u64 avg_idle; |
562 | #endif |
563 | |
564 | /* calc_load related fields */ |
565 | unsigned long calc_load_update; |
566 | long calc_load_active; |
567 | |
568 | #ifdef CONFIG_SCHED_HRTICK |
569 | #ifdef CONFIG_SMP |
570 | int hrtick_csd_pending; |
571 | struct call_single_data hrtick_csd; |
572 | #endif |
573 | struct hrtimer hrtick_timer; |
574 | #endif |
575 | |
576 | #ifdef CONFIG_SCHEDSTATS |
577 | /* latency stats */ |
578 | struct sched_info rq_sched_info; |
579 | unsigned long long rq_cpu_time; |
580 | /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */ |
581 | |
582 | /* sys_sched_yield() stats */ |
583 | unsigned int yld_count; |
584 | |
585 | /* schedule() stats */ |
586 | unsigned int sched_switch; |
587 | unsigned int sched_count; |
588 | unsigned int sched_goidle; |
589 | |
590 | /* try_to_wake_up() stats */ |
591 | unsigned int ttwu_count; |
592 | unsigned int ttwu_local; |
593 | |
594 | /* BKL stats */ |
595 | unsigned int bkl_count; |
596 | #endif |
597 | }; |
598 | |
599 | static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
600 | |
601 | static inline |
602 | void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) |
603 | { |
604 | rq->curr->sched_class->check_preempt_curr(rq, p, flags); |
605 | } |
606 | |
607 | static inline int cpu_of(struct rq *rq) |
608 | { |
609 | #ifdef CONFIG_SMP |
610 | return rq->cpu; |
611 | #else |
612 | return 0; |
613 | #endif |
614 | } |
615 | |
616 | #define rcu_dereference_check_sched_domain(p) \ |
617 | rcu_dereference_check((p), \ |
618 | rcu_read_lock_sched_held() || \ |
619 | lockdep_is_held(&sched_domains_mutex)) |
620 | |
621 | /* |
622 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. |
623 | * See detach_destroy_domains: synchronize_sched for details. |
624 | * |
625 | * The domain tree of any CPU may only be accessed from within |
626 | * preempt-disabled sections. |
627 | */ |
628 | #define for_each_domain(cpu, __sd) \ |
629 | for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) |
630 | |
631 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) |
632 | #define this_rq() (&__get_cpu_var(runqueues)) |
633 | #define task_rq(p) cpu_rq(task_cpu(p)) |
634 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) |
635 | #define raw_rq() (&__raw_get_cpu_var(runqueues)) |
636 | |
637 | inline void update_rq_clock(struct rq *rq) |
638 | { |
639 | rq->clock = sched_clock_cpu(cpu_of(rq)); |
640 | } |
641 | |
642 | /* |
643 | * Tunables that become constants when CONFIG_SCHED_DEBUG is off: |
644 | */ |
645 | #ifdef CONFIG_SCHED_DEBUG |
646 | # define const_debug __read_mostly |
647 | #else |
648 | # define const_debug static const |
649 | #endif |
650 | |
651 | /** |
652 | * runqueue_is_locked |
653 | * @cpu: the processor in question. |
654 | * |
655 | * Returns true if the current cpu runqueue is locked. |
656 | * This interface allows printk to be called with the runqueue lock |
657 | * held and know whether or not it is OK to wake up the klogd. |
658 | */ |
659 | int runqueue_is_locked(int cpu) |
660 | { |
661 | return raw_spin_is_locked(&cpu_rq(cpu)->lock); |
662 | } |
663 | |
664 | /* |
665 | * Debugging: various feature bits |
666 | */ |
667 | |
668 | #define SCHED_FEAT(name, enabled) \ |
669 | __SCHED_FEAT_##name , |
670 | |
671 | enum { |
672 | #include "sched_features.h" |
673 | }; |
674 | |
675 | #undef SCHED_FEAT |
676 | |
677 | #define SCHED_FEAT(name, enabled) \ |
678 | (1UL << __SCHED_FEAT_##name) * enabled | |
679 | |
680 | const_debug unsigned int sysctl_sched_features = |
681 | #include "sched_features.h" |
682 | 0; |
683 | |
684 | #undef SCHED_FEAT |
685 | |
686 | #ifdef CONFIG_SCHED_DEBUG |
687 | #define SCHED_FEAT(name, enabled) \ |
688 | #name , |
689 | |
690 | static __read_mostly char *sched_feat_names[] = { |
691 | #include "sched_features.h" |
692 | NULL |
693 | }; |
694 | |
695 | #undef SCHED_FEAT |
696 | |
697 | static int sched_feat_show(struct seq_file *m, void *v) |
698 | { |
699 | int i; |
700 | |
701 | for (i = 0; sched_feat_names[i]; i++) { |
702 | if (!(sysctl_sched_features & (1UL << i))) |
703 | seq_puts(m, "NO_"); |
704 | seq_printf(m, "%s ", sched_feat_names[i]); |
705 | } |
706 | seq_puts(m, "\n"); |
707 | |
708 | return 0; |
709 | } |
710 | |
711 | static ssize_t |
712 | sched_feat_write(struct file *filp, const char __user *ubuf, |
713 | size_t cnt, loff_t *ppos) |
714 | { |
715 | char buf[64]; |
716 | char *cmp = buf; |
717 | int neg = 0; |
718 | int i; |
719 | |
720 | if (cnt > 63) |
721 | cnt = 63; |
722 | |
723 | if (copy_from_user(&buf, ubuf, cnt)) |
724 | return -EFAULT; |
725 | |
726 | buf[cnt] = 0; |
727 | |
728 | if (strncmp(buf, "NO_", 3) == 0) { |
729 | neg = 1; |
730 | cmp += 3; |
731 | } |
732 | |
733 | for (i = 0; sched_feat_names[i]; i++) { |
734 | int len = strlen(sched_feat_names[i]); |
735 | |
736 | if (strncmp(cmp, sched_feat_names[i], len) == 0) { |
737 | if (neg) |
738 | sysctl_sched_features &= ~(1UL << i); |
739 | else |
740 | sysctl_sched_features |= (1UL << i); |
741 | break; |
742 | } |
743 | } |
744 | |
745 | if (!sched_feat_names[i]) |
746 | return -EINVAL; |
747 | |
748 | *ppos += cnt; |
749 | |
750 | return cnt; |
751 | } |
752 | |
753 | static int sched_feat_open(struct inode *inode, struct file *filp) |
754 | { |
755 | return single_open(filp, sched_feat_show, NULL); |
756 | } |
757 | |
758 | static const struct file_operations sched_feat_fops = { |
759 | .open = sched_feat_open, |
760 | .write = sched_feat_write, |
761 | .read = seq_read, |
762 | .llseek = seq_lseek, |
763 | .release = single_release, |
764 | }; |
765 | |
766 | static __init int sched_init_debug(void) |
767 | { |
768 | debugfs_create_file("sched_features", 0644, NULL, NULL, |
769 | &sched_feat_fops); |
770 | |
771 | return 0; |
772 | } |
773 | late_initcall(sched_init_debug); |
774 | |
775 | #endif |
776 | |
777 | #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) |
778 | |
779 | /* |
780 | * Number of tasks to iterate in a single balance run. |
781 | * Limited because this is done with IRQs disabled. |
782 | */ |
783 | const_debug unsigned int sysctl_sched_nr_migrate = 32; |
784 | |
785 | /* |
786 | * ratelimit for updating the group shares. |
787 | * default: 0.25ms |
788 | */ |
789 | unsigned int sysctl_sched_shares_ratelimit = 250000; |
790 | unsigned int normalized_sysctl_sched_shares_ratelimit = 250000; |
791 | |
792 | /* |
793 | * Inject some fuzzyness into changing the per-cpu group shares |
794 | * this avoids remote rq-locks at the expense of fairness. |
795 | * default: 4 |
796 | */ |
797 | unsigned int sysctl_sched_shares_thresh = 4; |
798 | |
799 | /* |
800 | * period over which we average the RT time consumption, measured |
801 | * in ms. |
802 | * |
803 | * default: 1s |
804 | */ |
805 | const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; |
806 | |
807 | /* |
808 | * period over which we measure -rt task cpu usage in us. |
809 | * default: 1s |
810 | */ |
811 | unsigned int sysctl_sched_rt_period = 1000000; |
812 | |
813 | static __read_mostly int scheduler_running; |
814 | |
815 | /* |
816 | * part of the period that we allow rt tasks to run in us. |
817 | * default: 0.95s |
818 | */ |
819 | int sysctl_sched_rt_runtime = 950000; |
820 | |
821 | static inline u64 global_rt_period(void) |
822 | { |
823 | return (u64)sysctl_sched_rt_period * NSEC_PER_USEC; |
824 | } |
825 | |
826 | static inline u64 global_rt_runtime(void) |
827 | { |
828 | if (sysctl_sched_rt_runtime < 0) |
829 | return RUNTIME_INF; |
830 | |
831 | return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC; |
832 | } |
833 | |
834 | #ifndef prepare_arch_switch |
835 | # define prepare_arch_switch(next) do { } while (0) |
836 | #endif |
837 | #ifndef finish_arch_switch |
838 | # define finish_arch_switch(prev) do { } while (0) |
839 | #endif |
840 | |
841 | static inline int task_current(struct rq *rq, struct task_struct *p) |
842 | { |
843 | return rq->curr == p; |
844 | } |
845 | |
846 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
847 | static inline int task_running(struct rq *rq, struct task_struct *p) |
848 | { |
849 | return task_current(rq, p); |
850 | } |
851 | |
852 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
853 | { |
854 | } |
855 | |
856 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
857 | { |
858 | #ifdef CONFIG_DEBUG_SPINLOCK |
859 | /* this is a valid case when another task releases the spinlock */ |
860 | rq->lock.owner = current; |
861 | #endif |
862 | /* |
863 | * If we are tracking spinlock dependencies then we have to |
864 | * fix up the runqueue lock - which gets 'carried over' from |
865 | * prev into current: |
866 | */ |
867 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); |
868 | |
869 | raw_spin_unlock_irq(&rq->lock); |
870 | } |
871 | |
872 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ |
873 | static inline int task_running(struct rq *rq, struct task_struct *p) |
874 | { |
875 | #ifdef CONFIG_SMP |
876 | return p->oncpu; |
877 | #else |
878 | return task_current(rq, p); |
879 | #endif |
880 | } |
881 | |
882 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
883 | { |
884 | #ifdef CONFIG_SMP |
885 | /* |
886 | * We can optimise this out completely for !SMP, because the |
887 | * SMP rebalancing from interrupt is the only thing that cares |
888 | * here. |
889 | */ |
890 | next->oncpu = 1; |
891 | #endif |
892 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
893 | raw_spin_unlock_irq(&rq->lock); |
894 | #else |
895 | raw_spin_unlock(&rq->lock); |
896 | #endif |
897 | } |
898 | |
899 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
900 | { |
901 | #ifdef CONFIG_SMP |
902 | /* |
903 | * After ->oncpu is cleared, the task can be moved to a different CPU. |
904 | * We must ensure this doesn't happen until the switch is completely |
905 | * finished. |
906 | */ |
907 | smp_wmb(); |
908 | prev->oncpu = 0; |
909 | #endif |
910 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
911 | local_irq_enable(); |
912 | #endif |
913 | } |
914 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ |
915 | |
916 | /* |
917 | * Check whether the task is waking, we use this to synchronize against |
918 | * ttwu() so that task_cpu() reports a stable number. |
919 | * |
920 | * We need to make an exception for PF_STARTING tasks because the fork |
921 | * path might require task_rq_lock() to work, eg. it can call |
922 | * set_cpus_allowed_ptr() from the cpuset clone_ns code. |
923 | */ |
924 | static inline int task_is_waking(struct task_struct *p) |
925 | { |
926 | return unlikely((p->state == TASK_WAKING) && !(p->flags & PF_STARTING)); |
927 | } |
928 | |
929 | /* |
930 | * __task_rq_lock - lock the runqueue a given task resides on. |
931 | * Must be called interrupts disabled. |
932 | */ |
933 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
934 | __acquires(rq->lock) |
935 | { |
936 | struct rq *rq; |
937 | |
938 | for (;;) { |
939 | while (task_is_waking(p)) |
940 | cpu_relax(); |
941 | rq = task_rq(p); |
942 | raw_spin_lock(&rq->lock); |
943 | if (likely(rq == task_rq(p) && !task_is_waking(p))) |
944 | return rq; |
945 | raw_spin_unlock(&rq->lock); |
946 | } |
947 | } |
948 | |
949 | /* |
950 | * task_rq_lock - lock the runqueue a given task resides on and disable |
951 | * interrupts. Note the ordering: we can safely lookup the task_rq without |
952 | * explicitly disabling preemption. |
953 | */ |
954 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
955 | __acquires(rq->lock) |
956 | { |
957 | struct rq *rq; |
958 | |
959 | for (;;) { |
960 | while (task_is_waking(p)) |
961 | cpu_relax(); |
962 | local_irq_save(*flags); |
963 | rq = task_rq(p); |
964 | raw_spin_lock(&rq->lock); |
965 | if (likely(rq == task_rq(p) && !task_is_waking(p))) |
966 | return rq; |
967 | raw_spin_unlock_irqrestore(&rq->lock, *flags); |
968 | } |
969 | } |
970 | |
971 | void task_rq_unlock_wait(struct task_struct *p) |
972 | { |
973 | struct rq *rq = task_rq(p); |
974 | |
975 | smp_mb(); /* spin-unlock-wait is not a full memory barrier */ |
976 | raw_spin_unlock_wait(&rq->lock); |
977 | } |
978 | |
979 | static void __task_rq_unlock(struct rq *rq) |
980 | __releases(rq->lock) |
981 | { |
982 | raw_spin_unlock(&rq->lock); |
983 | } |
984 | |
985 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
986 | __releases(rq->lock) |
987 | { |
988 | raw_spin_unlock_irqrestore(&rq->lock, *flags); |
989 | } |
990 | |
991 | /* |
992 | * this_rq_lock - lock this runqueue and disable interrupts. |
993 | */ |
994 | static struct rq *this_rq_lock(void) |
995 | __acquires(rq->lock) |
996 | { |
997 | struct rq *rq; |
998 | |
999 | local_irq_disable(); |
1000 | rq = this_rq(); |
1001 | raw_spin_lock(&rq->lock); |
1002 | |
1003 | return rq; |
1004 | } |
1005 | |
1006 | #ifdef CONFIG_SCHED_HRTICK |
1007 | /* |
1008 | * Use HR-timers to deliver accurate preemption points. |
1009 | * |
1010 | * Its all a bit involved since we cannot program an hrt while holding the |
1011 | * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a |
1012 | * reschedule event. |
1013 | * |
1014 | * When we get rescheduled we reprogram the hrtick_timer outside of the |
1015 | * rq->lock. |
1016 | */ |
1017 | |
1018 | /* |
1019 | * Use hrtick when: |
1020 | * - enabled by features |
1021 | * - hrtimer is actually high res |
1022 | */ |
1023 | static inline int hrtick_enabled(struct rq *rq) |
1024 | { |
1025 | if (!sched_feat(HRTICK)) |
1026 | return 0; |
1027 | if (!cpu_active(cpu_of(rq))) |
1028 | return 0; |
1029 | return hrtimer_is_hres_active(&rq->hrtick_timer); |
1030 | } |
1031 | |
1032 | static void hrtick_clear(struct rq *rq) |
1033 | { |
1034 | if (hrtimer_active(&rq->hrtick_timer)) |
1035 | hrtimer_cancel(&rq->hrtick_timer); |
1036 | } |
1037 | |
1038 | /* |
1039 | * High-resolution timer tick. |
1040 | * Runs from hardirq context with interrupts disabled. |
1041 | */ |
1042 | static enum hrtimer_restart hrtick(struct hrtimer *timer) |
1043 | { |
1044 | struct rq *rq = container_of(timer, struct rq, hrtick_timer); |
1045 | |
1046 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); |
1047 | |
1048 | raw_spin_lock(&rq->lock); |
1049 | update_rq_clock(rq); |
1050 | rq->curr->sched_class->task_tick(rq, rq->curr, 1); |
1051 | raw_spin_unlock(&rq->lock); |
1052 | |
1053 | return HRTIMER_NORESTART; |
1054 | } |
1055 | |
1056 | #ifdef CONFIG_SMP |
1057 | /* |
1058 | * called from hardirq (IPI) context |
1059 | */ |
1060 | static void __hrtick_start(void *arg) |
1061 | { |
1062 | struct rq *rq = arg; |
1063 | |
1064 | raw_spin_lock(&rq->lock); |
1065 | hrtimer_restart(&rq->hrtick_timer); |
1066 | rq->hrtick_csd_pending = 0; |
1067 | raw_spin_unlock(&rq->lock); |
1068 | } |
1069 | |
1070 | /* |
1071 | * Called to set the hrtick timer state. |
1072 | * |
1073 | * called with rq->lock held and irqs disabled |
1074 | */ |
1075 | static void hrtick_start(struct rq *rq, u64 delay) |
1076 | { |
1077 | struct hrtimer *timer = &rq->hrtick_timer; |
1078 | ktime_t time = ktime_add_ns(timer->base->get_time(), delay); |
1079 | |
1080 | hrtimer_set_expires(timer, time); |
1081 | |
1082 | if (rq == this_rq()) { |
1083 | hrtimer_restart(timer); |
1084 | } else if (!rq->hrtick_csd_pending) { |
1085 | __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); |
1086 | rq->hrtick_csd_pending = 1; |
1087 | } |
1088 | } |
1089 | |
1090 | static int |
1091 | hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) |
1092 | { |
1093 | int cpu = (int)(long)hcpu; |
1094 | |
1095 | switch (action) { |
1096 | case CPU_UP_CANCELED: |
1097 | case CPU_UP_CANCELED_FROZEN: |
1098 | case CPU_DOWN_PREPARE: |
1099 | case CPU_DOWN_PREPARE_FROZEN: |
1100 | case CPU_DEAD: |
1101 | case CPU_DEAD_FROZEN: |
1102 | hrtick_clear(cpu_rq(cpu)); |
1103 | return NOTIFY_OK; |
1104 | } |
1105 | |
1106 | return NOTIFY_DONE; |
1107 | } |
1108 | |
1109 | static __init void init_hrtick(void) |
1110 | { |
1111 | hotcpu_notifier(hotplug_hrtick, 0); |
1112 | } |
1113 | #else |
1114 | /* |
1115 | * Called to set the hrtick timer state. |
1116 | * |
1117 | * called with rq->lock held and irqs disabled |
1118 | */ |
1119 | static void hrtick_start(struct rq *rq, u64 delay) |
1120 | { |
1121 | __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, |
1122 | HRTIMER_MODE_REL_PINNED, 0); |
1123 | } |
1124 | |
1125 | static inline void init_hrtick(void) |
1126 | { |
1127 | } |
1128 | #endif /* CONFIG_SMP */ |
1129 | |
1130 | static void init_rq_hrtick(struct rq *rq) |
1131 | { |
1132 | #ifdef CONFIG_SMP |
1133 | rq->hrtick_csd_pending = 0; |
1134 | |
1135 | rq->hrtick_csd.flags = 0; |
1136 | rq->hrtick_csd.func = __hrtick_start; |
1137 | rq->hrtick_csd.info = rq; |
1138 | #endif |
1139 | |
1140 | hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
1141 | rq->hrtick_timer.function = hrtick; |
1142 | } |
1143 | #else /* CONFIG_SCHED_HRTICK */ |
1144 | static inline void hrtick_clear(struct rq *rq) |
1145 | { |
1146 | } |
1147 | |
1148 | static inline void init_rq_hrtick(struct rq *rq) |
1149 | { |
1150 | } |
1151 | |
1152 | static inline void init_hrtick(void) |
1153 | { |
1154 | } |
1155 | #endif /* CONFIG_SCHED_HRTICK */ |
1156 | |
1157 | /* |
1158 | * resched_task - mark a task 'to be rescheduled now'. |
1159 | * |
1160 | * On UP this means the setting of the need_resched flag, on SMP it |
1161 | * might also involve a cross-CPU call to trigger the scheduler on |
1162 | * the target CPU. |
1163 | */ |
1164 | #ifdef CONFIG_SMP |
1165 | |
1166 | #ifndef tsk_is_polling |
1167 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) |
1168 | #endif |
1169 | |
1170 | static void resched_task(struct task_struct *p) |
1171 | { |
1172 | int cpu; |
1173 | |
1174 | assert_raw_spin_locked(&task_rq(p)->lock); |
1175 | |
1176 | if (test_tsk_need_resched(p)) |
1177 | return; |
1178 | |
1179 | set_tsk_need_resched(p); |
1180 | |
1181 | cpu = task_cpu(p); |
1182 | if (cpu == smp_processor_id()) |
1183 | return; |
1184 | |
1185 | /* NEED_RESCHED must be visible before we test polling */ |
1186 | smp_mb(); |
1187 | if (!tsk_is_polling(p)) |
1188 | smp_send_reschedule(cpu); |
1189 | } |
1190 | |
1191 | static void resched_cpu(int cpu) |
1192 | { |
1193 | struct rq *rq = cpu_rq(cpu); |
1194 | unsigned long flags; |
1195 | |
1196 | if (!raw_spin_trylock_irqsave(&rq->lock, flags)) |
1197 | return; |
1198 | resched_task(cpu_curr(cpu)); |
1199 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
1200 | } |
1201 | |
1202 | #ifdef CONFIG_NO_HZ |
1203 | /* |
1204 | * When add_timer_on() enqueues a timer into the timer wheel of an |
1205 | * idle CPU then this timer might expire before the next timer event |
1206 | * which is scheduled to wake up that CPU. In case of a completely |
1207 | * idle system the next event might even be infinite time into the |
1208 | * future. wake_up_idle_cpu() ensures that the CPU is woken up and |
1209 | * leaves the inner idle loop so the newly added timer is taken into |
1210 | * account when the CPU goes back to idle and evaluates the timer |
1211 | * wheel for the next timer event. |
1212 | */ |
1213 | void wake_up_idle_cpu(int cpu) |
1214 | { |
1215 | struct rq *rq = cpu_rq(cpu); |
1216 | |
1217 | if (cpu == smp_processor_id()) |
1218 | return; |
1219 | |
1220 | /* |
1221 | * This is safe, as this function is called with the timer |
1222 | * wheel base lock of (cpu) held. When the CPU is on the way |
1223 | * to idle and has not yet set rq->curr to idle then it will |
1224 | * be serialized on the timer wheel base lock and take the new |
1225 | * timer into account automatically. |
1226 | */ |
1227 | if (rq->curr != rq->idle) |
1228 | return; |
1229 | |
1230 | /* |
1231 | * We can set TIF_RESCHED on the idle task of the other CPU |
1232 | * lockless. The worst case is that the other CPU runs the |
1233 | * idle task through an additional NOOP schedule() |
1234 | */ |
1235 | set_tsk_need_resched(rq->idle); |
1236 | |
1237 | /* NEED_RESCHED must be visible before we test polling */ |
1238 | smp_mb(); |
1239 | if (!tsk_is_polling(rq->idle)) |
1240 | smp_send_reschedule(cpu); |
1241 | } |
1242 | #endif /* CONFIG_NO_HZ */ |
1243 | |
1244 | static u64 sched_avg_period(void) |
1245 | { |
1246 | return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2; |
1247 | } |
1248 | |
1249 | static void sched_avg_update(struct rq *rq) |
1250 | { |
1251 | s64 period = sched_avg_period(); |
1252 | |
1253 | while ((s64)(rq->clock - rq->age_stamp) > period) { |
1254 | rq->age_stamp += period; |
1255 | rq->rt_avg /= 2; |
1256 | } |
1257 | } |
1258 | |
1259 | static void sched_rt_avg_update(struct rq *rq, u64 rt_delta) |
1260 | { |
1261 | rq->rt_avg += rt_delta; |
1262 | sched_avg_update(rq); |
1263 | } |
1264 | |
1265 | #else /* !CONFIG_SMP */ |
1266 | static void resched_task(struct task_struct *p) |
1267 | { |
1268 | assert_raw_spin_locked(&task_rq(p)->lock); |
1269 | set_tsk_need_resched(p); |
1270 | } |
1271 | |
1272 | static void sched_rt_avg_update(struct rq *rq, u64 rt_delta) |
1273 | { |
1274 | } |
1275 | #endif /* CONFIG_SMP */ |
1276 | |
1277 | #if BITS_PER_LONG == 32 |
1278 | # define WMULT_CONST (~0UL) |
1279 | #else |
1280 | # define WMULT_CONST (1UL << 32) |
1281 | #endif |
1282 | |
1283 | #define WMULT_SHIFT 32 |
1284 | |
1285 | /* |
1286 | * Shift right and round: |
1287 | */ |
1288 | #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) |
1289 | |
1290 | /* |
1291 | * delta *= weight / lw |
1292 | */ |
1293 | static unsigned long |
1294 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
1295 | struct load_weight *lw) |
1296 | { |
1297 | u64 tmp; |
1298 | |
1299 | if (!lw->inv_weight) { |
1300 | if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST)) |
1301 | lw->inv_weight = 1; |
1302 | else |
1303 | lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2) |
1304 | / (lw->weight+1); |
1305 | } |
1306 | |
1307 | tmp = (u64)delta_exec * weight; |
1308 | /* |
1309 | * Check whether we'd overflow the 64-bit multiplication: |
1310 | */ |
1311 | if (unlikely(tmp > WMULT_CONST)) |
1312 | tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, |
1313 | WMULT_SHIFT/2); |
1314 | else |
1315 | tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); |
1316 | |
1317 | return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); |
1318 | } |
1319 | |
1320 | static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
1321 | { |
1322 | lw->weight += inc; |
1323 | lw->inv_weight = 0; |
1324 | } |
1325 | |
1326 | static inline void update_load_sub(struct load_weight *lw, unsigned long dec) |
1327 | { |
1328 | lw->weight -= dec; |
1329 | lw->inv_weight = 0; |
1330 | } |
1331 | |
1332 | /* |
1333 | * To aid in avoiding the subversion of "niceness" due to uneven distribution |
1334 | * of tasks with abnormal "nice" values across CPUs the contribution that |
1335 | * each task makes to its run queue's load is weighted according to its |
1336 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a |
1337 | * scaled version of the new time slice allocation that they receive on time |
1338 | * slice expiry etc. |
1339 | */ |
1340 | |
1341 | #define WEIGHT_IDLEPRIO 3 |
1342 | #define WMULT_IDLEPRIO 1431655765 |
1343 | |
1344 | /* |
1345 | * Nice levels are multiplicative, with a gentle 10% change for every |
1346 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to |
1347 | * nice 1, it will get ~10% less CPU time than another CPU-bound task |
1348 | * that remained on nice 0. |
1349 | * |
1350 | * The "10% effect" is relative and cumulative: from _any_ nice level, |
1351 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level |
1352 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. |
1353 | * If a task goes up by ~10% and another task goes down by ~10% then |
1354 | * the relative distance between them is ~25%.) |
1355 | */ |
1356 | static const int prio_to_weight[40] = { |
1357 | /* -20 */ 88761, 71755, 56483, 46273, 36291, |
1358 | /* -15 */ 29154, 23254, 18705, 14949, 11916, |
1359 | /* -10 */ 9548, 7620, 6100, 4904, 3906, |
1360 | /* -5 */ 3121, 2501, 1991, 1586, 1277, |
1361 | /* 0 */ 1024, 820, 655, 526, 423, |
1362 | /* 5 */ 335, 272, 215, 172, 137, |
1363 | /* 10 */ 110, 87, 70, 56, 45, |
1364 | /* 15 */ 36, 29, 23, 18, 15, |
1365 | }; |
1366 | |
1367 | /* |
1368 | * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. |
1369 | * |
1370 | * In cases where the weight does not change often, we can use the |
1371 | * precalculated inverse to speed up arithmetics by turning divisions |
1372 | * into multiplications: |
1373 | */ |
1374 | static const u32 prio_to_wmult[40] = { |
1375 | /* -20 */ 48388, 59856, 76040, 92818, 118348, |
1376 | /* -15 */ 147320, 184698, 229616, 287308, 360437, |
1377 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, |
1378 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, |
1379 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, |
1380 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, |
1381 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, |
1382 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, |
1383 | }; |
1384 | |
1385 | /* Time spent by the tasks of the cpu accounting group executing in ... */ |
1386 | enum cpuacct_stat_index { |
1387 | CPUACCT_STAT_USER, /* ... user mode */ |
1388 | CPUACCT_STAT_SYSTEM, /* ... kernel mode */ |
1389 | |
1390 | CPUACCT_STAT_NSTATS, |
1391 | }; |
1392 | |
1393 | #ifdef CONFIG_CGROUP_CPUACCT |
1394 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime); |
1395 | static void cpuacct_update_stats(struct task_struct *tsk, |
1396 | enum cpuacct_stat_index idx, cputime_t val); |
1397 | #else |
1398 | static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} |
1399 | static inline void cpuacct_update_stats(struct task_struct *tsk, |
1400 | enum cpuacct_stat_index idx, cputime_t val) {} |
1401 | #endif |
1402 | |
1403 | static inline void inc_cpu_load(struct rq *rq, unsigned long load) |
1404 | { |
1405 | update_load_add(&rq->load, load); |
1406 | } |
1407 | |
1408 | static inline void dec_cpu_load(struct rq *rq, unsigned long load) |
1409 | { |
1410 | update_load_sub(&rq->load, load); |
1411 | } |
1412 | |
1413 | #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED) |
1414 | typedef int (*tg_visitor)(struct task_group *, void *); |
1415 | |
1416 | /* |
1417 | * Iterate the full tree, calling @down when first entering a node and @up when |
1418 | * leaving it for the final time. |
1419 | */ |
1420 | static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data) |
1421 | { |
1422 | struct task_group *parent, *child; |
1423 | int ret; |
1424 | |
1425 | rcu_read_lock(); |
1426 | parent = &root_task_group; |
1427 | down: |
1428 | ret = (*down)(parent, data); |
1429 | if (ret) |
1430 | goto out_unlock; |
1431 | list_for_each_entry_rcu(child, &parent->children, siblings) { |
1432 | parent = child; |
1433 | goto down; |
1434 | |
1435 | up: |
1436 | continue; |
1437 | } |
1438 | ret = (*up)(parent, data); |
1439 | if (ret) |
1440 | goto out_unlock; |
1441 | |
1442 | child = parent; |
1443 | parent = parent->parent; |
1444 | if (parent) |
1445 | goto up; |
1446 | out_unlock: |
1447 | rcu_read_unlock(); |
1448 | |
1449 | return ret; |
1450 | } |
1451 | |
1452 | static int tg_nop(struct task_group *tg, void *data) |
1453 | { |
1454 | return 0; |
1455 | } |
1456 | #endif |
1457 | |
1458 | #ifdef CONFIG_SMP |
1459 | /* Used instead of source_load when we know the type == 0 */ |
1460 | static unsigned long weighted_cpuload(const int cpu) |
1461 | { |
1462 | return cpu_rq(cpu)->load.weight; |
1463 | } |
1464 | |
1465 | /* |
1466 | * Return a low guess at the load of a migration-source cpu weighted |
1467 | * according to the scheduling class and "nice" value. |
1468 | * |
1469 | * We want to under-estimate the load of migration sources, to |
1470 | * balance conservatively. |
1471 | */ |
1472 | static unsigned long source_load(int cpu, int type) |
1473 | { |
1474 | struct rq *rq = cpu_rq(cpu); |
1475 | unsigned long total = weighted_cpuload(cpu); |
1476 | |
1477 | if (type == 0 || !sched_feat(LB_BIAS)) |
1478 | return total; |
1479 | |
1480 | return min(rq->cpu_load[type-1], total); |
1481 | } |
1482 | |
1483 | /* |
1484 | * Return a high guess at the load of a migration-target cpu weighted |
1485 | * according to the scheduling class and "nice" value. |
1486 | */ |
1487 | static unsigned long target_load(int cpu, int type) |
1488 | { |
1489 | struct rq *rq = cpu_rq(cpu); |
1490 | unsigned long total = weighted_cpuload(cpu); |
1491 | |
1492 | if (type == 0 || !sched_feat(LB_BIAS)) |
1493 | return total; |
1494 | |
1495 | return max(rq->cpu_load[type-1], total); |
1496 | } |
1497 | |
1498 | static struct sched_group *group_of(int cpu) |
1499 | { |
1500 | struct sched_domain *sd = rcu_dereference_sched(cpu_rq(cpu)->sd); |
1501 | |
1502 | if (!sd) |
1503 | return NULL; |
1504 | |
1505 | return sd->groups; |
1506 | } |
1507 | |
1508 | static unsigned long power_of(int cpu) |
1509 | { |
1510 | struct sched_group *group = group_of(cpu); |
1511 | |
1512 | if (!group) |
1513 | return SCHED_LOAD_SCALE; |
1514 | |
1515 | return group->cpu_power; |
1516 | } |
1517 | |
1518 | static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); |
1519 | |
1520 | static unsigned long cpu_avg_load_per_task(int cpu) |
1521 | { |
1522 | struct rq *rq = cpu_rq(cpu); |
1523 | unsigned long nr_running = ACCESS_ONCE(rq->nr_running); |
1524 | |
1525 | if (nr_running) |
1526 | rq->avg_load_per_task = rq->load.weight / nr_running; |
1527 | else |
1528 | rq->avg_load_per_task = 0; |
1529 | |
1530 | return rq->avg_load_per_task; |
1531 | } |
1532 | |
1533 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1534 | |
1535 | static __read_mostly unsigned long __percpu *update_shares_data; |
1536 | |
1537 | static void __set_se_shares(struct sched_entity *se, unsigned long shares); |
1538 | |
1539 | /* |
1540 | * Calculate and set the cpu's group shares. |
1541 | */ |
1542 | static void update_group_shares_cpu(struct task_group *tg, int cpu, |
1543 | unsigned long sd_shares, |
1544 | unsigned long sd_rq_weight, |
1545 | unsigned long *usd_rq_weight) |
1546 | { |
1547 | unsigned long shares, rq_weight; |
1548 | int boost = 0; |
1549 | |
1550 | rq_weight = usd_rq_weight[cpu]; |
1551 | if (!rq_weight) { |
1552 | boost = 1; |
1553 | rq_weight = NICE_0_LOAD; |
1554 | } |
1555 | |
1556 | /* |
1557 | * \Sum_j shares_j * rq_weight_i |
1558 | * shares_i = ----------------------------- |
1559 | * \Sum_j rq_weight_j |
1560 | */ |
1561 | shares = (sd_shares * rq_weight) / sd_rq_weight; |
1562 | shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES); |
1563 | |
1564 | if (abs(shares - tg->se[cpu]->load.weight) > |
1565 | sysctl_sched_shares_thresh) { |
1566 | struct rq *rq = cpu_rq(cpu); |
1567 | unsigned long flags; |
1568 | |
1569 | raw_spin_lock_irqsave(&rq->lock, flags); |
1570 | tg->cfs_rq[cpu]->rq_weight = boost ? 0 : rq_weight; |
1571 | tg->cfs_rq[cpu]->shares = boost ? 0 : shares; |
1572 | __set_se_shares(tg->se[cpu], shares); |
1573 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
1574 | } |
1575 | } |
1576 | |
1577 | /* |
1578 | * Re-compute the task group their per cpu shares over the given domain. |
1579 | * This needs to be done in a bottom-up fashion because the rq weight of a |
1580 | * parent group depends on the shares of its child groups. |
1581 | */ |
1582 | static int tg_shares_up(struct task_group *tg, void *data) |
1583 | { |
1584 | unsigned long weight, rq_weight = 0, sum_weight = 0, shares = 0; |
1585 | unsigned long *usd_rq_weight; |
1586 | struct sched_domain *sd = data; |
1587 | unsigned long flags; |
1588 | int i; |
1589 | |
1590 | if (!tg->se[0]) |
1591 | return 0; |
1592 | |
1593 | local_irq_save(flags); |
1594 | usd_rq_weight = per_cpu_ptr(update_shares_data, smp_processor_id()); |
1595 | |
1596 | for_each_cpu(i, sched_domain_span(sd)) { |
1597 | weight = tg->cfs_rq[i]->load.weight; |
1598 | usd_rq_weight[i] = weight; |
1599 | |
1600 | rq_weight += weight; |
1601 | /* |
1602 | * If there are currently no tasks on the cpu pretend there |
1603 | * is one of average load so that when a new task gets to |
1604 | * run here it will not get delayed by group starvation. |
1605 | */ |
1606 | if (!weight) |
1607 | weight = NICE_0_LOAD; |
1608 | |
1609 | sum_weight += weight; |
1610 | shares += tg->cfs_rq[i]->shares; |
1611 | } |
1612 | |
1613 | if (!rq_weight) |
1614 | rq_weight = sum_weight; |
1615 | |
1616 | if ((!shares && rq_weight) || shares > tg->shares) |
1617 | shares = tg->shares; |
1618 | |
1619 | if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) |
1620 | shares = tg->shares; |
1621 | |
1622 | for_each_cpu(i, sched_domain_span(sd)) |
1623 | update_group_shares_cpu(tg, i, shares, rq_weight, usd_rq_weight); |
1624 | |
1625 | local_irq_restore(flags); |
1626 | |
1627 | return 0; |
1628 | } |
1629 | |
1630 | /* |
1631 | * Compute the cpu's hierarchical load factor for each task group. |
1632 | * This needs to be done in a top-down fashion because the load of a child |
1633 | * group is a fraction of its parents load. |
1634 | */ |
1635 | static int tg_load_down(struct task_group *tg, void *data) |
1636 | { |
1637 | unsigned long load; |
1638 | long cpu = (long)data; |
1639 | |
1640 | if (!tg->parent) { |
1641 | load = cpu_rq(cpu)->load.weight; |
1642 | } else { |
1643 | load = tg->parent->cfs_rq[cpu]->h_load; |
1644 | load *= tg->cfs_rq[cpu]->shares; |
1645 | load /= tg->parent->cfs_rq[cpu]->load.weight + 1; |
1646 | } |
1647 | |
1648 | tg->cfs_rq[cpu]->h_load = load; |
1649 | |
1650 | return 0; |
1651 | } |
1652 | |
1653 | static void update_shares(struct sched_domain *sd) |
1654 | { |
1655 | s64 elapsed; |
1656 | u64 now; |
1657 | |
1658 | if (root_task_group_empty()) |
1659 | return; |
1660 | |
1661 | now = cpu_clock(raw_smp_processor_id()); |
1662 | elapsed = now - sd->last_update; |
1663 | |
1664 | if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) { |
1665 | sd->last_update = now; |
1666 | walk_tg_tree(tg_nop, tg_shares_up, sd); |
1667 | } |
1668 | } |
1669 | |
1670 | static void update_h_load(long cpu) |
1671 | { |
1672 | if (root_task_group_empty()) |
1673 | return; |
1674 | |
1675 | walk_tg_tree(tg_load_down, tg_nop, (void *)cpu); |
1676 | } |
1677 | |
1678 | #else |
1679 | |
1680 | static inline void update_shares(struct sched_domain *sd) |
1681 | { |
1682 | } |
1683 | |
1684 | #endif |
1685 | |
1686 | #ifdef CONFIG_PREEMPT |
1687 | |
1688 | static void double_rq_lock(struct rq *rq1, struct rq *rq2); |
1689 | |
1690 | /* |
1691 | * fair double_lock_balance: Safely acquires both rq->locks in a fair |
1692 | * way at the expense of forcing extra atomic operations in all |
1693 | * invocations. This assures that the double_lock is acquired using the |
1694 | * same underlying policy as the spinlock_t on this architecture, which |
1695 | * reduces latency compared to the unfair variant below. However, it |
1696 | * also adds more overhead and therefore may reduce throughput. |
1697 | */ |
1698 | static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1699 | __releases(this_rq->lock) |
1700 | __acquires(busiest->lock) |
1701 | __acquires(this_rq->lock) |
1702 | { |
1703 | raw_spin_unlock(&this_rq->lock); |
1704 | double_rq_lock(this_rq, busiest); |
1705 | |
1706 | return 1; |
1707 | } |
1708 | |
1709 | #else |
1710 | /* |
1711 | * Unfair double_lock_balance: Optimizes throughput at the expense of |
1712 | * latency by eliminating extra atomic operations when the locks are |
1713 | * already in proper order on entry. This favors lower cpu-ids and will |
1714 | * grant the double lock to lower cpus over higher ids under contention, |
1715 | * regardless of entry order into the function. |
1716 | */ |
1717 | static int _double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1718 | __releases(this_rq->lock) |
1719 | __acquires(busiest->lock) |
1720 | __acquires(this_rq->lock) |
1721 | { |
1722 | int ret = 0; |
1723 | |
1724 | if (unlikely(!raw_spin_trylock(&busiest->lock))) { |
1725 | if (busiest < this_rq) { |
1726 | raw_spin_unlock(&this_rq->lock); |
1727 | raw_spin_lock(&busiest->lock); |
1728 | raw_spin_lock_nested(&this_rq->lock, |
1729 | SINGLE_DEPTH_NESTING); |
1730 | ret = 1; |
1731 | } else |
1732 | raw_spin_lock_nested(&busiest->lock, |
1733 | SINGLE_DEPTH_NESTING); |
1734 | } |
1735 | return ret; |
1736 | } |
1737 | |
1738 | #endif /* CONFIG_PREEMPT */ |
1739 | |
1740 | /* |
1741 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. |
1742 | */ |
1743 | static int double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1744 | { |
1745 | if (unlikely(!irqs_disabled())) { |
1746 | /* printk() doesn't work good under rq->lock */ |
1747 | raw_spin_unlock(&this_rq->lock); |
1748 | BUG_ON(1); |
1749 | } |
1750 | |
1751 | return _double_lock_balance(this_rq, busiest); |
1752 | } |
1753 | |
1754 | static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest) |
1755 | __releases(busiest->lock) |
1756 | { |
1757 | raw_spin_unlock(&busiest->lock); |
1758 | lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_); |
1759 | } |
1760 | |
1761 | /* |
1762 | * double_rq_lock - safely lock two runqueues |
1763 | * |
1764 | * Note this does not disable interrupts like task_rq_lock, |
1765 | * you need to do so manually before calling. |
1766 | */ |
1767 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
1768 | __acquires(rq1->lock) |
1769 | __acquires(rq2->lock) |
1770 | { |
1771 | BUG_ON(!irqs_disabled()); |
1772 | if (rq1 == rq2) { |
1773 | raw_spin_lock(&rq1->lock); |
1774 | __acquire(rq2->lock); /* Fake it out ;) */ |
1775 | } else { |
1776 | if (rq1 < rq2) { |
1777 | raw_spin_lock(&rq1->lock); |
1778 | raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING); |
1779 | } else { |
1780 | raw_spin_lock(&rq2->lock); |
1781 | raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING); |
1782 | } |
1783 | } |
1784 | update_rq_clock(rq1); |
1785 | update_rq_clock(rq2); |
1786 | } |
1787 | |
1788 | /* |
1789 | * double_rq_unlock - safely unlock two runqueues |
1790 | * |
1791 | * Note this does not restore interrupts like task_rq_unlock, |
1792 | * you need to do so manually after calling. |
1793 | */ |
1794 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
1795 | __releases(rq1->lock) |
1796 | __releases(rq2->lock) |
1797 | { |
1798 | raw_spin_unlock(&rq1->lock); |
1799 | if (rq1 != rq2) |
1800 | raw_spin_unlock(&rq2->lock); |
1801 | else |
1802 | __release(rq2->lock); |
1803 | } |
1804 | |
1805 | #endif |
1806 | |
1807 | #ifdef CONFIG_FAIR_GROUP_SCHED |
1808 | static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) |
1809 | { |
1810 | #ifdef CONFIG_SMP |
1811 | cfs_rq->shares = shares; |
1812 | #endif |
1813 | } |
1814 | #endif |
1815 | |
1816 | static void calc_load_account_active(struct rq *this_rq); |
1817 | static void update_sysctl(void); |
1818 | static int get_update_sysctl_factor(void); |
1819 | |
1820 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) |
1821 | { |
1822 | set_task_rq(p, cpu); |
1823 | #ifdef CONFIG_SMP |
1824 | /* |
1825 | * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be |
1826 | * successfuly executed on another CPU. We must ensure that updates of |
1827 | * per-task data have been completed by this moment. |
1828 | */ |
1829 | smp_wmb(); |
1830 | task_thread_info(p)->cpu = cpu; |
1831 | #endif |
1832 | } |
1833 | |
1834 | static const struct sched_class rt_sched_class; |
1835 | |
1836 | #define sched_class_highest (&rt_sched_class) |
1837 | #define for_each_class(class) \ |
1838 | for (class = sched_class_highest; class; class = class->next) |
1839 | |
1840 | #include "sched_stats.h" |
1841 | |
1842 | static void inc_nr_running(struct rq *rq) |
1843 | { |
1844 | rq->nr_running++; |
1845 | } |
1846 | |
1847 | static void dec_nr_running(struct rq *rq) |
1848 | { |
1849 | rq->nr_running--; |
1850 | } |
1851 | |
1852 | static void set_load_weight(struct task_struct *p) |
1853 | { |
1854 | if (task_has_rt_policy(p)) { |
1855 | p->se.load.weight = prio_to_weight[0] * 2; |
1856 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; |
1857 | return; |
1858 | } |
1859 | |
1860 | /* |
1861 | * SCHED_IDLE tasks get minimal weight: |
1862 | */ |
1863 | if (p->policy == SCHED_IDLE) { |
1864 | p->se.load.weight = WEIGHT_IDLEPRIO; |
1865 | p->se.load.inv_weight = WMULT_IDLEPRIO; |
1866 | return; |
1867 | } |
1868 | |
1869 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
1870 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; |
1871 | } |
1872 | |
1873 | static void update_avg(u64 *avg, u64 sample) |
1874 | { |
1875 | s64 diff = sample - *avg; |
1876 | *avg += diff >> 3; |
1877 | } |
1878 | |
1879 | static void |
1880 | enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head) |
1881 | { |
1882 | if (wakeup) |
1883 | p->se.start_runtime = p->se.sum_exec_runtime; |
1884 | |
1885 | sched_info_queued(p); |
1886 | p->sched_class->enqueue_task(rq, p, wakeup, head); |
1887 | p->se.on_rq = 1; |
1888 | } |
1889 | |
1890 | static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) |
1891 | { |
1892 | if (sleep) { |
1893 | if (p->se.last_wakeup) { |
1894 | update_avg(&p->se.avg_overlap, |
1895 | p->se.sum_exec_runtime - p->se.last_wakeup); |
1896 | p->se.last_wakeup = 0; |
1897 | } else { |
1898 | update_avg(&p->se.avg_wakeup, |
1899 | sysctl_sched_wakeup_granularity); |
1900 | } |
1901 | } |
1902 | |
1903 | sched_info_dequeued(p); |
1904 | p->sched_class->dequeue_task(rq, p, sleep); |
1905 | p->se.on_rq = 0; |
1906 | } |
1907 | |
1908 | /* |
1909 | * activate_task - move a task to the runqueue. |
1910 | */ |
1911 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1912 | { |
1913 | if (task_contributes_to_load(p)) |
1914 | rq->nr_uninterruptible--; |
1915 | |
1916 | enqueue_task(rq, p, wakeup, false); |
1917 | inc_nr_running(rq); |
1918 | } |
1919 | |
1920 | /* |
1921 | * deactivate_task - remove a task from the runqueue. |
1922 | */ |
1923 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1924 | { |
1925 | if (task_contributes_to_load(p)) |
1926 | rq->nr_uninterruptible++; |
1927 | |
1928 | dequeue_task(rq, p, sleep); |
1929 | dec_nr_running(rq); |
1930 | } |
1931 | |
1932 | #include "sched_idletask.c" |
1933 | #include "sched_fair.c" |
1934 | #include "sched_rt.c" |
1935 | #ifdef CONFIG_SCHED_DEBUG |
1936 | # include "sched_debug.c" |
1937 | #endif |
1938 | |
1939 | /* |
1940 | * __normal_prio - return the priority that is based on the static prio |
1941 | */ |
1942 | static inline int __normal_prio(struct task_struct *p) |
1943 | { |
1944 | return p->static_prio; |
1945 | } |
1946 | |
1947 | /* |
1948 | * Calculate the expected normal priority: i.e. priority |
1949 | * without taking RT-inheritance into account. Might be |
1950 | * boosted by interactivity modifiers. Changes upon fork, |
1951 | * setprio syscalls, and whenever the interactivity |
1952 | * estimator recalculates. |
1953 | */ |
1954 | static inline int normal_prio(struct task_struct *p) |
1955 | { |
1956 | int prio; |
1957 | |
1958 | if (task_has_rt_policy(p)) |
1959 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
1960 | else |
1961 | prio = __normal_prio(p); |
1962 | return prio; |
1963 | } |
1964 | |
1965 | /* |
1966 | * Calculate the current priority, i.e. the priority |
1967 | * taken into account by the scheduler. This value might |
1968 | * be boosted by RT tasks, or might be boosted by |
1969 | * interactivity modifiers. Will be RT if the task got |
1970 | * RT-boosted. If not then it returns p->normal_prio. |
1971 | */ |
1972 | static int effective_prio(struct task_struct *p) |
1973 | { |
1974 | p->normal_prio = normal_prio(p); |
1975 | /* |
1976 | * If we are RT tasks or we were boosted to RT priority, |
1977 | * keep the priority unchanged. Otherwise, update priority |
1978 | * to the normal priority: |
1979 | */ |
1980 | if (!rt_prio(p->prio)) |
1981 | return p->normal_prio; |
1982 | return p->prio; |
1983 | } |
1984 | |
1985 | /** |
1986 | * task_curr - is this task currently executing on a CPU? |
1987 | * @p: the task in question. |
1988 | */ |
1989 | inline int task_curr(const struct task_struct *p) |
1990 | { |
1991 | return cpu_curr(task_cpu(p)) == p; |
1992 | } |
1993 | |
1994 | static inline void check_class_changed(struct rq *rq, struct task_struct *p, |
1995 | const struct sched_class *prev_class, |
1996 | int oldprio, int running) |
1997 | { |
1998 | if (prev_class != p->sched_class) { |
1999 | if (prev_class->switched_from) |
2000 | prev_class->switched_from(rq, p, running); |
2001 | p->sched_class->switched_to(rq, p, running); |
2002 | } else |
2003 | p->sched_class->prio_changed(rq, p, oldprio, running); |
2004 | } |
2005 | |
2006 | #ifdef CONFIG_SMP |
2007 | /* |
2008 | * Is this task likely cache-hot: |
2009 | */ |
2010 | static int |
2011 | task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) |
2012 | { |
2013 | s64 delta; |
2014 | |
2015 | if (p->sched_class != &fair_sched_class) |
2016 | return 0; |
2017 | |
2018 | /* |
2019 | * Buddy candidates are cache hot: |
2020 | */ |
2021 | if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running && |
2022 | (&p->se == cfs_rq_of(&p->se)->next || |
2023 | &p->se == cfs_rq_of(&p->se)->last)) |
2024 | return 1; |
2025 | |
2026 | if (sysctl_sched_migration_cost == -1) |
2027 | return 1; |
2028 | if (sysctl_sched_migration_cost == 0) |
2029 | return 0; |
2030 | |
2031 | delta = now - p->se.exec_start; |
2032 | |
2033 | return delta < (s64)sysctl_sched_migration_cost; |
2034 | } |
2035 | |
2036 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
2037 | { |
2038 | #ifdef CONFIG_SCHED_DEBUG |
2039 | /* |
2040 | * We should never call set_task_cpu() on a blocked task, |
2041 | * ttwu() will sort out the placement. |
2042 | */ |
2043 | WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && |
2044 | !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); |
2045 | #endif |
2046 | |
2047 | trace_sched_migrate_task(p, new_cpu); |
2048 | |
2049 | if (task_cpu(p) != new_cpu) { |
2050 | p->se.nr_migrations++; |
2051 | perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, 1, NULL, 0); |
2052 | } |
2053 | |
2054 | __set_task_cpu(p, new_cpu); |
2055 | } |
2056 | |
2057 | struct migration_req { |
2058 | struct list_head list; |
2059 | |
2060 | struct task_struct *task; |
2061 | int dest_cpu; |
2062 | |
2063 | struct completion done; |
2064 | }; |
2065 | |
2066 | /* |
2067 | * The task's runqueue lock must be held. |
2068 | * Returns true if you have to wait for migration thread. |
2069 | */ |
2070 | static int |
2071 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
2072 | { |
2073 | struct rq *rq = task_rq(p); |
2074 | |
2075 | /* |
2076 | * If the task is not on a runqueue (and not running), then |
2077 | * the next wake-up will properly place the task. |
2078 | */ |
2079 | if (!p->se.on_rq && !task_running(rq, p)) |
2080 | return 0; |
2081 | |
2082 | init_completion(&req->done); |
2083 | req->task = p; |
2084 | req->dest_cpu = dest_cpu; |
2085 | list_add(&req->list, &rq->migration_queue); |
2086 | |
2087 | return 1; |
2088 | } |
2089 | |
2090 | /* |
2091 | * wait_task_context_switch - wait for a thread to complete at least one |
2092 | * context switch. |
2093 | * |
2094 | * @p must not be current. |
2095 | */ |
2096 | void wait_task_context_switch(struct task_struct *p) |
2097 | { |
2098 | unsigned long nvcsw, nivcsw, flags; |
2099 | int running; |
2100 | struct rq *rq; |
2101 | |
2102 | nvcsw = p->nvcsw; |
2103 | nivcsw = p->nivcsw; |
2104 | for (;;) { |
2105 | /* |
2106 | * The runqueue is assigned before the actual context |
2107 | * switch. We need to take the runqueue lock. |
2108 | * |
2109 | * We could check initially without the lock but it is |
2110 | * very likely that we need to take the lock in every |
2111 | * iteration. |
2112 | */ |
2113 | rq = task_rq_lock(p, &flags); |
2114 | running = task_running(rq, p); |
2115 | task_rq_unlock(rq, &flags); |
2116 | |
2117 | if (likely(!running)) |
2118 | break; |
2119 | /* |
2120 | * The switch count is incremented before the actual |
2121 | * context switch. We thus wait for two switches to be |
2122 | * sure at least one completed. |
2123 | */ |
2124 | if ((p->nvcsw - nvcsw) > 1) |
2125 | break; |
2126 | if ((p->nivcsw - nivcsw) > 1) |
2127 | break; |
2128 | |
2129 | cpu_relax(); |
2130 | } |
2131 | } |
2132 | |
2133 | /* |
2134 | * wait_task_inactive - wait for a thread to unschedule. |
2135 | * |
2136 | * If @match_state is nonzero, it's the @p->state value just checked and |
2137 | * not expected to change. If it changes, i.e. @p might have woken up, |
2138 | * then return zero. When we succeed in waiting for @p to be off its CPU, |
2139 | * we return a positive number (its total switch count). If a second call |
2140 | * a short while later returns the same number, the caller can be sure that |
2141 | * @p has remained unscheduled the whole time. |
2142 | * |
2143 | * The caller must ensure that the task *will* unschedule sometime soon, |
2144 | * else this function might spin for a *long* time. This function can't |
2145 | * be called with interrupts off, or it may introduce deadlock with |
2146 | * smp_call_function() if an IPI is sent by the same process we are |
2147 | * waiting to become inactive. |
2148 | */ |
2149 | unsigned long wait_task_inactive(struct task_struct *p, long match_state) |
2150 | { |
2151 | unsigned long flags; |
2152 | int running, on_rq; |
2153 | unsigned long ncsw; |
2154 | struct rq *rq; |
2155 | |
2156 | for (;;) { |
2157 | /* |
2158 | * We do the initial early heuristics without holding |
2159 | * any task-queue locks at all. We'll only try to get |
2160 | * the runqueue lock when things look like they will |
2161 | * work out! |
2162 | */ |
2163 | rq = task_rq(p); |
2164 | |
2165 | /* |
2166 | * If the task is actively running on another CPU |
2167 | * still, just relax and busy-wait without holding |
2168 | * any locks. |
2169 | * |
2170 | * NOTE! Since we don't hold any locks, it's not |
2171 | * even sure that "rq" stays as the right runqueue! |
2172 | * But we don't care, since "task_running()" will |
2173 | * return false if the runqueue has changed and p |
2174 | * is actually now running somewhere else! |
2175 | */ |
2176 | while (task_running(rq, p)) { |
2177 | if (match_state && unlikely(p->state != match_state)) |
2178 | return 0; |
2179 | cpu_relax(); |
2180 | } |
2181 | |
2182 | /* |
2183 | * Ok, time to look more closely! We need the rq |
2184 | * lock now, to be *sure*. If we're wrong, we'll |
2185 | * just go back and repeat. |
2186 | */ |
2187 | rq = task_rq_lock(p, &flags); |
2188 | trace_sched_wait_task(rq, p); |
2189 | running = task_running(rq, p); |
2190 | on_rq = p->se.on_rq; |
2191 | ncsw = 0; |
2192 | if (!match_state || p->state == match_state) |
2193 | ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ |
2194 | task_rq_unlock(rq, &flags); |
2195 | |
2196 | /* |
2197 | * If it changed from the expected state, bail out now. |
2198 | */ |
2199 | if (unlikely(!ncsw)) |
2200 | break; |
2201 | |
2202 | /* |
2203 | * Was it really running after all now that we |
2204 | * checked with the proper locks actually held? |
2205 | * |
2206 | * Oops. Go back and try again.. |
2207 | */ |
2208 | if (unlikely(running)) { |
2209 | cpu_relax(); |
2210 | continue; |
2211 | } |
2212 | |
2213 | /* |
2214 | * It's not enough that it's not actively running, |
2215 | * it must be off the runqueue _entirely_, and not |
2216 | * preempted! |
2217 | * |
2218 | * So if it was still runnable (but just not actively |
2219 | * running right now), it's preempted, and we should |
2220 | * yield - it could be a while. |
2221 | */ |
2222 | if (unlikely(on_rq)) { |
2223 | schedule_timeout_uninterruptible(1); |
2224 | continue; |
2225 | } |
2226 | |
2227 | /* |
2228 | * Ahh, all good. It wasn't running, and it wasn't |
2229 | * runnable, which means that it will never become |
2230 | * running in the future either. We're all done! |
2231 | */ |
2232 | break; |
2233 | } |
2234 | |
2235 | return ncsw; |
2236 | } |
2237 | |
2238 | /*** |
2239 | * kick_process - kick a running thread to enter/exit the kernel |
2240 | * @p: the to-be-kicked thread |
2241 | * |
2242 | * Cause a process which is running on another CPU to enter |
2243 | * kernel-mode, without any delay. (to get signals handled.) |
2244 | * |
2245 | * NOTE: this function doesnt have to take the runqueue lock, |
2246 | * because all it wants to ensure is that the remote task enters |
2247 | * the kernel. If the IPI races and the task has been migrated |
2248 | * to another CPU then no harm is done and the purpose has been |
2249 | * achieved as well. |
2250 | */ |
2251 | void kick_process(struct task_struct *p) |
2252 | { |
2253 | int cpu; |
2254 | |
2255 | preempt_disable(); |
2256 | cpu = task_cpu(p); |
2257 | if ((cpu != smp_processor_id()) && task_curr(p)) |
2258 | smp_send_reschedule(cpu); |
2259 | preempt_enable(); |
2260 | } |
2261 | EXPORT_SYMBOL_GPL(kick_process); |
2262 | #endif /* CONFIG_SMP */ |
2263 | |
2264 | /** |
2265 | * task_oncpu_function_call - call a function on the cpu on which a task runs |
2266 | * @p: the task to evaluate |
2267 | * @func: the function to be called |
2268 | * @info: the function call argument |
2269 | * |
2270 | * Calls the function @func when the task is currently running. This might |
2271 | * be on the current CPU, which just calls the function directly |
2272 | */ |
2273 | void task_oncpu_function_call(struct task_struct *p, |
2274 | void (*func) (void *info), void *info) |
2275 | { |
2276 | int cpu; |
2277 | |
2278 | preempt_disable(); |
2279 | cpu = task_cpu(p); |
2280 | if (task_curr(p)) |
2281 | smp_call_function_single(cpu, func, info, 1); |
2282 | preempt_enable(); |
2283 | } |
2284 | |
2285 | #ifdef CONFIG_SMP |
2286 | static int select_fallback_rq(int cpu, struct task_struct *p) |
2287 | { |
2288 | int dest_cpu; |
2289 | const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu)); |
2290 | |
2291 | /* Look for allowed, online CPU in same node. */ |
2292 | for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask) |
2293 | if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed)) |
2294 | return dest_cpu; |
2295 | |
2296 | /* Any allowed, online CPU? */ |
2297 | dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask); |
2298 | if (dest_cpu < nr_cpu_ids) |
2299 | return dest_cpu; |
2300 | |
2301 | /* No more Mr. Nice Guy. */ |
2302 | if (dest_cpu >= nr_cpu_ids) { |
2303 | rcu_read_lock(); |
2304 | cpuset_cpus_allowed_locked(p, &p->cpus_allowed); |
2305 | rcu_read_unlock(); |
2306 | dest_cpu = cpumask_any_and(cpu_active_mask, &p->cpus_allowed); |
2307 | |
2308 | /* |
2309 | * Don't tell them about moving exiting tasks or |
2310 | * kernel threads (both mm NULL), since they never |
2311 | * leave kernel. |
2312 | */ |
2313 | if (p->mm && printk_ratelimit()) { |
2314 | printk(KERN_INFO "process %d (%s) no " |
2315 | "longer affine to cpu%d\n", |
2316 | task_pid_nr(p), p->comm, cpu); |
2317 | } |
2318 | } |
2319 | |
2320 | return dest_cpu; |
2321 | } |
2322 | |
2323 | /* |
2324 | * Gets called from 3 sites (exec, fork, wakeup), since it is called without |
2325 | * holding rq->lock we need to ensure ->cpus_allowed is stable, this is done |
2326 | * by: |
2327 | * |
2328 | * exec: is unstable, retry loop |
2329 | * fork & wake-up: serialize ->cpus_allowed against TASK_WAKING |
2330 | */ |
2331 | static inline |
2332 | int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) |
2333 | { |
2334 | int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags); |
2335 | |
2336 | /* |
2337 | * In order not to call set_task_cpu() on a blocking task we need |
2338 | * to rely on ttwu() to place the task on a valid ->cpus_allowed |
2339 | * cpu. |
2340 | * |
2341 | * Since this is common to all placement strategies, this lives here. |
2342 | * |
2343 | * [ this allows ->select_task() to simply return task_cpu(p) and |
2344 | * not worry about this generic constraint ] |
2345 | */ |
2346 | if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) || |
2347 | !cpu_online(cpu))) |
2348 | cpu = select_fallback_rq(task_cpu(p), p); |
2349 | |
2350 | return cpu; |
2351 | } |
2352 | #endif |
2353 | |
2354 | /*** |
2355 | * try_to_wake_up - wake up a thread |
2356 | * @p: the to-be-woken-up thread |
2357 | * @state: the mask of task states that can be woken |
2358 | * @sync: do a synchronous wakeup? |
2359 | * |
2360 | * Put it on the run-queue if it's not already there. The "current" |
2361 | * thread is always on the run-queue (except when the actual |
2362 | * re-schedule is in progress), and as such you're allowed to do |
2363 | * the simpler "current->state = TASK_RUNNING" to mark yourself |
2364 | * runnable without the overhead of this. |
2365 | * |
2366 | * returns failure only if the task is already active. |
2367 | */ |
2368 | static int try_to_wake_up(struct task_struct *p, unsigned int state, |
2369 | int wake_flags) |
2370 | { |
2371 | int cpu, orig_cpu, this_cpu, success = 0; |
2372 | unsigned long flags; |
2373 | struct rq *rq; |
2374 | |
2375 | if (!sched_feat(SYNC_WAKEUPS)) |
2376 | wake_flags &= ~WF_SYNC; |
2377 | |
2378 | this_cpu = get_cpu(); |
2379 | |
2380 | smp_wmb(); |
2381 | rq = task_rq_lock(p, &flags); |
2382 | update_rq_clock(rq); |
2383 | if (!(p->state & state)) |
2384 | goto out; |
2385 | |
2386 | if (p->se.on_rq) |
2387 | goto out_running; |
2388 | |
2389 | cpu = task_cpu(p); |
2390 | orig_cpu = cpu; |
2391 | |
2392 | #ifdef CONFIG_SMP |
2393 | if (unlikely(task_running(rq, p))) |
2394 | goto out_activate; |
2395 | |
2396 | /* |
2397 | * In order to handle concurrent wakeups and release the rq->lock |
2398 | * we put the task in TASK_WAKING state. |
2399 | * |
2400 | * First fix up the nr_uninterruptible count: |
2401 | */ |
2402 | if (task_contributes_to_load(p)) |
2403 | rq->nr_uninterruptible--; |
2404 | p->state = TASK_WAKING; |
2405 | |
2406 | if (p->sched_class->task_waking) |
2407 | p->sched_class->task_waking(rq, p); |
2408 | |
2409 | __task_rq_unlock(rq); |
2410 | |
2411 | cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); |
2412 | if (cpu != orig_cpu) { |
2413 | /* |
2414 | * Since we migrate the task without holding any rq->lock, |
2415 | * we need to be careful with task_rq_lock(), since that |
2416 | * might end up locking an invalid rq. |
2417 | */ |
2418 | set_task_cpu(p, cpu); |
2419 | } |
2420 | |
2421 | rq = cpu_rq(cpu); |
2422 | raw_spin_lock(&rq->lock); |
2423 | update_rq_clock(rq); |
2424 | |
2425 | /* |
2426 | * We migrated the task without holding either rq->lock, however |
2427 | * since the task is not on the task list itself, nobody else |
2428 | * will try and migrate the task, hence the rq should match the |
2429 | * cpu we just moved it to. |
2430 | */ |
2431 | WARN_ON(task_cpu(p) != cpu); |
2432 | WARN_ON(p->state != TASK_WAKING); |
2433 | |
2434 | #ifdef CONFIG_SCHEDSTATS |
2435 | schedstat_inc(rq, ttwu_count); |
2436 | if (cpu == this_cpu) |
2437 | schedstat_inc(rq, ttwu_local); |
2438 | else { |
2439 | struct sched_domain *sd; |
2440 | for_each_domain(this_cpu, sd) { |
2441 | if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
2442 | schedstat_inc(sd, ttwu_wake_remote); |
2443 | break; |
2444 | } |
2445 | } |
2446 | } |
2447 | #endif /* CONFIG_SCHEDSTATS */ |
2448 | |
2449 | out_activate: |
2450 | #endif /* CONFIG_SMP */ |
2451 | schedstat_inc(p, se.nr_wakeups); |
2452 | if (wake_flags & WF_SYNC) |
2453 | schedstat_inc(p, se.nr_wakeups_sync); |
2454 | if (orig_cpu != cpu) |
2455 | schedstat_inc(p, se.nr_wakeups_migrate); |
2456 | if (cpu == this_cpu) |
2457 | schedstat_inc(p, se.nr_wakeups_local); |
2458 | else |
2459 | schedstat_inc(p, se.nr_wakeups_remote); |
2460 | activate_task(rq, p, 1); |
2461 | success = 1; |
2462 | |
2463 | /* |
2464 | * Only attribute actual wakeups done by this task. |
2465 | */ |
2466 | if (!in_interrupt()) { |
2467 | struct sched_entity *se = ¤t->se; |
2468 | u64 sample = se->sum_exec_runtime; |
2469 | |
2470 | if (se->last_wakeup) |
2471 | sample -= se->last_wakeup; |
2472 | else |
2473 | sample -= se->start_runtime; |
2474 | update_avg(&se->avg_wakeup, sample); |
2475 | |
2476 | se->last_wakeup = se->sum_exec_runtime; |
2477 | } |
2478 | |
2479 | out_running: |
2480 | trace_sched_wakeup(rq, p, success); |
2481 | check_preempt_curr(rq, p, wake_flags); |
2482 | |
2483 | p->state = TASK_RUNNING; |
2484 | #ifdef CONFIG_SMP |
2485 | if (p->sched_class->task_woken) |
2486 | p->sched_class->task_woken(rq, p); |
2487 | |
2488 | if (unlikely(rq->idle_stamp)) { |
2489 | u64 delta = rq->clock - rq->idle_stamp; |
2490 | u64 max = 2*sysctl_sched_migration_cost; |
2491 | |
2492 | if (delta > max) |
2493 | rq->avg_idle = max; |
2494 | else |
2495 | update_avg(&rq->avg_idle, delta); |
2496 | rq->idle_stamp = 0; |
2497 | } |
2498 | #endif |
2499 | out: |
2500 | task_rq_unlock(rq, &flags); |
2501 | put_cpu(); |
2502 | |
2503 | return success; |
2504 | } |
2505 | |
2506 | /** |
2507 | * wake_up_process - Wake up a specific process |
2508 | * @p: The process to be woken up. |
2509 | * |
2510 | * Attempt to wake up the nominated process and move it to the set of runnable |
2511 | * processes. Returns 1 if the process was woken up, 0 if it was already |
2512 | * running. |
2513 | * |
2514 | * It may be assumed that this function implies a write memory barrier before |
2515 | * changing the task state if and only if any tasks are woken up. |
2516 | */ |
2517 | int wake_up_process(struct task_struct *p) |
2518 | { |
2519 | return try_to_wake_up(p, TASK_ALL, 0); |
2520 | } |
2521 | EXPORT_SYMBOL(wake_up_process); |
2522 | |
2523 | int wake_up_state(struct task_struct *p, unsigned int state) |
2524 | { |
2525 | return try_to_wake_up(p, state, 0); |
2526 | } |
2527 | |
2528 | /* |
2529 | * Perform scheduler related setup for a newly forked process p. |
2530 | * p is forked by current. |
2531 | * |
2532 | * __sched_fork() is basic setup used by init_idle() too: |
2533 | */ |
2534 | static void __sched_fork(struct task_struct *p) |
2535 | { |
2536 | p->se.exec_start = 0; |
2537 | p->se.sum_exec_runtime = 0; |
2538 | p->se.prev_sum_exec_runtime = 0; |
2539 | p->se.nr_migrations = 0; |
2540 | p->se.last_wakeup = 0; |
2541 | p->se.avg_overlap = 0; |
2542 | p->se.start_runtime = 0; |
2543 | p->se.avg_wakeup = sysctl_sched_wakeup_granularity; |
2544 | |
2545 | #ifdef CONFIG_SCHEDSTATS |
2546 | p->se.wait_start = 0; |
2547 | p->se.wait_max = 0; |
2548 | p->se.wait_count = 0; |
2549 | p->se.wait_sum = 0; |
2550 | |
2551 | p->se.sleep_start = 0; |
2552 | p->se.sleep_max = 0; |
2553 | p->se.sum_sleep_runtime = 0; |
2554 | |
2555 | p->se.block_start = 0; |
2556 | p->se.block_max = 0; |
2557 | p->se.exec_max = 0; |
2558 | p->se.slice_max = 0; |
2559 | |
2560 | p->se.nr_migrations_cold = 0; |
2561 | p->se.nr_failed_migrations_affine = 0; |
2562 | p->se.nr_failed_migrations_running = 0; |
2563 | p->se.nr_failed_migrations_hot = 0; |
2564 | p->se.nr_forced_migrations = 0; |
2565 | |
2566 | p->se.nr_wakeups = 0; |
2567 | p->se.nr_wakeups_sync = 0; |
2568 | p->se.nr_wakeups_migrate = 0; |
2569 | p->se.nr_wakeups_local = 0; |
2570 | p->se.nr_wakeups_remote = 0; |
2571 | p->se.nr_wakeups_affine = 0; |
2572 | p->se.nr_wakeups_affine_attempts = 0; |
2573 | p->se.nr_wakeups_passive = 0; |
2574 | p->se.nr_wakeups_idle = 0; |
2575 | |
2576 | #endif |
2577 | |
2578 | INIT_LIST_HEAD(&p->rt.run_list); |
2579 | p->se.on_rq = 0; |
2580 | INIT_LIST_HEAD(&p->se.group_node); |
2581 | |
2582 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
2583 | INIT_HLIST_HEAD(&p->preempt_notifiers); |
2584 | #endif |
2585 | } |
2586 | |
2587 | /* |
2588 | * fork()/clone()-time setup: |
2589 | */ |
2590 | void sched_fork(struct task_struct *p, int clone_flags) |
2591 | { |
2592 | int cpu = get_cpu(); |
2593 | |
2594 | __sched_fork(p); |
2595 | /* |
2596 | * We mark the process as waking here. This guarantees that |
2597 | * nobody will actually run it, and a signal or other external |
2598 | * event cannot wake it up and insert it on the runqueue either. |
2599 | */ |
2600 | p->state = TASK_WAKING; |
2601 | |
2602 | /* |
2603 | * Revert to default priority/policy on fork if requested. |
2604 | */ |
2605 | if (unlikely(p->sched_reset_on_fork)) { |
2606 | if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) { |
2607 | p->policy = SCHED_NORMAL; |
2608 | p->normal_prio = p->static_prio; |
2609 | } |
2610 | |
2611 | if (PRIO_TO_NICE(p->static_prio) < 0) { |
2612 | p->static_prio = NICE_TO_PRIO(0); |
2613 | p->normal_prio = p->static_prio; |
2614 | set_load_weight(p); |
2615 | } |
2616 | |
2617 | /* |
2618 | * We don't need the reset flag anymore after the fork. It has |
2619 | * fulfilled its duty: |
2620 | */ |
2621 | p->sched_reset_on_fork = 0; |
2622 | } |
2623 | |
2624 | /* |
2625 | * Make sure we do not leak PI boosting priority to the child. |
2626 | */ |
2627 | p->prio = current->normal_prio; |
2628 | |
2629 | if (!rt_prio(p->prio)) |
2630 | p->sched_class = &fair_sched_class; |
2631 | |
2632 | if (p->sched_class->task_fork) |
2633 | p->sched_class->task_fork(p); |
2634 | |
2635 | set_task_cpu(p, cpu); |
2636 | |
2637 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
2638 | if (likely(sched_info_on())) |
2639 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
2640 | #endif |
2641 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
2642 | p->oncpu = 0; |
2643 | #endif |
2644 | #ifdef CONFIG_PREEMPT |
2645 | /* Want to start with kernel preemption disabled. */ |
2646 | task_thread_info(p)->preempt_count = 1; |
2647 | #endif |
2648 | plist_node_init(&p->pushable_tasks, MAX_PRIO); |
2649 | |
2650 | put_cpu(); |
2651 | } |
2652 | |
2653 | /* |
2654 | * wake_up_new_task - wake up a newly created task for the first time. |
2655 | * |
2656 | * This function will do some initial scheduler statistics housekeeping |
2657 | * that must be done for every newly created context, then puts the task |
2658 | * on the runqueue and wakes it. |
2659 | */ |
2660 | void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
2661 | { |
2662 | unsigned long flags; |
2663 | struct rq *rq; |
2664 | int cpu __maybe_unused = get_cpu(); |
2665 | |
2666 | #ifdef CONFIG_SMP |
2667 | /* |
2668 | * Fork balancing, do it here and not earlier because: |
2669 | * - cpus_allowed can change in the fork path |
2670 | * - any previously selected cpu might disappear through hotplug |
2671 | * |
2672 | * We still have TASK_WAKING but PF_STARTING is gone now, meaning |
2673 | * ->cpus_allowed is stable, we have preemption disabled, meaning |
2674 | * cpu_online_mask is stable. |
2675 | */ |
2676 | cpu = select_task_rq(p, SD_BALANCE_FORK, 0); |
2677 | set_task_cpu(p, cpu); |
2678 | #endif |
2679 | |
2680 | /* |
2681 | * Since the task is not on the rq and we still have TASK_WAKING set |
2682 | * nobody else will migrate this task. |
2683 | */ |
2684 | rq = cpu_rq(cpu); |
2685 | raw_spin_lock_irqsave(&rq->lock, flags); |
2686 | |
2687 | BUG_ON(p->state != TASK_WAKING); |
2688 | p->state = TASK_RUNNING; |
2689 | update_rq_clock(rq); |
2690 | activate_task(rq, p, 0); |
2691 | trace_sched_wakeup_new(rq, p, 1); |
2692 | check_preempt_curr(rq, p, WF_FORK); |
2693 | #ifdef CONFIG_SMP |
2694 | if (p->sched_class->task_woken) |
2695 | p->sched_class->task_woken(rq, p); |
2696 | #endif |
2697 | task_rq_unlock(rq, &flags); |
2698 | put_cpu(); |
2699 | } |
2700 | |
2701 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
2702 | |
2703 | /** |
2704 | * preempt_notifier_register - tell me when current is being preempted & rescheduled |
2705 | * @notifier: notifier struct to register |
2706 | */ |
2707 | void preempt_notifier_register(struct preempt_notifier *notifier) |
2708 | { |
2709 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); |
2710 | } |
2711 | EXPORT_SYMBOL_GPL(preempt_notifier_register); |
2712 | |
2713 | /** |
2714 | * preempt_notifier_unregister - no longer interested in preemption notifications |
2715 | * @notifier: notifier struct to unregister |
2716 | * |
2717 | * This is safe to call from within a preemption notifier. |
2718 | */ |
2719 | void preempt_notifier_unregister(struct preempt_notifier *notifier) |
2720 | { |
2721 | hlist_del(¬ifier->link); |
2722 | } |
2723 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); |
2724 | |
2725 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
2726 | { |
2727 | struct preempt_notifier *notifier; |
2728 | struct hlist_node *node; |
2729 | |
2730 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) |
2731 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); |
2732 | } |
2733 | |
2734 | static void |
2735 | fire_sched_out_preempt_notifiers(struct task_struct *curr, |
2736 | struct task_struct *next) |
2737 | { |
2738 | struct preempt_notifier *notifier; |
2739 | struct hlist_node *node; |
2740 | |
2741 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) |
2742 | notifier->ops->sched_out(notifier, next); |
2743 | } |
2744 | |
2745 | #else /* !CONFIG_PREEMPT_NOTIFIERS */ |
2746 | |
2747 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
2748 | { |
2749 | } |
2750 | |
2751 | static void |
2752 | fire_sched_out_preempt_notifiers(struct task_struct *curr, |
2753 | struct task_struct *next) |
2754 | { |
2755 | } |
2756 | |
2757 | #endif /* CONFIG_PREEMPT_NOTIFIERS */ |
2758 | |
2759 | /** |
2760 | * prepare_task_switch - prepare to switch tasks |
2761 | * @rq: the runqueue preparing to switch |
2762 | * @prev: the current task that is being switched out |
2763 | * @next: the task we are going to switch to. |
2764 | * |
2765 | * This is called with the rq lock held and interrupts off. It must |
2766 | * be paired with a subsequent finish_task_switch after the context |
2767 | * switch. |
2768 | * |
2769 | * prepare_task_switch sets up locking and calls architecture specific |
2770 | * hooks. |
2771 | */ |
2772 | static inline void |
2773 | prepare_task_switch(struct rq *rq, struct task_struct *prev, |
2774 | struct task_struct *next) |
2775 | { |
2776 | fire_sched_out_preempt_notifiers(prev, next); |
2777 | prepare_lock_switch(rq, next); |
2778 | prepare_arch_switch(next); |
2779 | } |
2780 | |
2781 | /** |
2782 | * finish_task_switch - clean up after a task-switch |
2783 | * @rq: runqueue associated with task-switch |
2784 | * @prev: the thread we just switched away from. |
2785 | * |
2786 | * finish_task_switch must be called after the context switch, paired |
2787 | * with a prepare_task_switch call before the context switch. |
2788 | * finish_task_switch will reconcile locking set up by prepare_task_switch, |
2789 | * and do any other architecture-specific cleanup actions. |
2790 | * |
2791 | * Note that we may have delayed dropping an mm in context_switch(). If |
2792 | * so, we finish that here outside of the runqueue lock. (Doing it |
2793 | * with the lock held can cause deadlocks; see schedule() for |
2794 | * details.) |
2795 | */ |
2796 | static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
2797 | __releases(rq->lock) |
2798 | { |
2799 | struct mm_struct *mm = rq->prev_mm; |
2800 | long prev_state; |
2801 | |
2802 | rq->prev_mm = NULL; |
2803 | |
2804 | /* |
2805 | * A task struct has one reference for the use as "current". |
2806 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
2807 | * schedule one last time. The schedule call will never return, and |
2808 | * the scheduled task must drop that reference. |
2809 | * The test for TASK_DEAD must occur while the runqueue locks are |
2810 | * still held, otherwise prev could be scheduled on another cpu, die |
2811 | * there before we look at prev->state, and then the reference would |
2812 | * be dropped twice. |
2813 | * Manfred Spraul <manfred@colorfullife.com> |
2814 | */ |
2815 | prev_state = prev->state; |
2816 | finish_arch_switch(prev); |
2817 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
2818 | local_irq_disable(); |
2819 | #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ |
2820 | perf_event_task_sched_in(current); |
2821 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
2822 | local_irq_enable(); |
2823 | #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ |
2824 | finish_lock_switch(rq, prev); |
2825 | |
2826 | fire_sched_in_preempt_notifiers(current); |
2827 | if (mm) |
2828 | mmdrop(mm); |
2829 | if (unlikely(prev_state == TASK_DEAD)) { |
2830 | /* |
2831 | * Remove function-return probe instances associated with this |
2832 | * task and put them back on the free list. |
2833 | */ |
2834 | kprobe_flush_task(prev); |
2835 | put_task_struct(prev); |
2836 | } |
2837 | } |
2838 | |
2839 | #ifdef CONFIG_SMP |
2840 | |
2841 | /* assumes rq->lock is held */ |
2842 | static inline void pre_schedule(struct rq *rq, struct task_struct *prev) |
2843 | { |
2844 | if (prev->sched_class->pre_schedule) |
2845 | prev->sched_class->pre_schedule(rq, prev); |
2846 | } |
2847 | |
2848 | /* rq->lock is NOT held, but preemption is disabled */ |
2849 | static inline void post_schedule(struct rq *rq) |
2850 | { |
2851 | if (rq->post_schedule) { |
2852 | unsigned long flags; |
2853 | |
2854 | raw_spin_lock_irqsave(&rq->lock, flags); |
2855 | if (rq->curr->sched_class->post_schedule) |
2856 | rq->curr->sched_class->post_schedule(rq); |
2857 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
2858 | |
2859 | rq->post_schedule = 0; |
2860 | } |
2861 | } |
2862 | |
2863 | #else |
2864 | |
2865 | static inline void pre_schedule(struct rq *rq, struct task_struct *p) |
2866 | { |
2867 | } |
2868 | |
2869 | static inline void post_schedule(struct rq *rq) |
2870 | { |
2871 | } |
2872 | |
2873 | #endif |
2874 | |
2875 | /** |
2876 | * schedule_tail - first thing a freshly forked thread must call. |
2877 | * @prev: the thread we just switched away from. |
2878 | */ |
2879 | asmlinkage void schedule_tail(struct task_struct *prev) |
2880 | __releases(rq->lock) |
2881 | { |
2882 | struct rq *rq = this_rq(); |
2883 | |
2884 | finish_task_switch(rq, prev); |
2885 | |
2886 | /* |
2887 | * FIXME: do we need to worry about rq being invalidated by the |
2888 | * task_switch? |
2889 | */ |
2890 | post_schedule(rq); |
2891 | |
2892 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW |
2893 | /* In this case, finish_task_switch does not reenable preemption */ |
2894 | preempt_enable(); |
2895 | #endif |
2896 | if (current->set_child_tid) |
2897 | put_user(task_pid_vnr(current), current->set_child_tid); |
2898 | } |
2899 | |
2900 | /* |
2901 | * context_switch - switch to the new MM and the new |
2902 | * thread's register state. |
2903 | */ |
2904 | static inline void |
2905 | context_switch(struct rq *rq, struct task_struct *prev, |
2906 | struct task_struct *next) |
2907 | { |
2908 | struct mm_struct *mm, *oldmm; |
2909 | |
2910 | prepare_task_switch(rq, prev, next); |
2911 | trace_sched_switch(rq, prev, next); |
2912 | mm = next->mm; |
2913 | oldmm = prev->active_mm; |
2914 | /* |
2915 | * For paravirt, this is coupled with an exit in switch_to to |
2916 | * combine the page table reload and the switch backend into |
2917 | * one hypercall. |
2918 | */ |
2919 | arch_start_context_switch(prev); |
2920 | |
2921 | if (likely(!mm)) { |
2922 | next->active_mm = oldmm; |
2923 | atomic_inc(&oldmm->mm_count); |
2924 | enter_lazy_tlb(oldmm, next); |
2925 | } else |
2926 | switch_mm(oldmm, mm, next); |
2927 | |
2928 | if (likely(!prev->mm)) { |
2929 | prev->active_mm = NULL; |
2930 | rq->prev_mm = oldmm; |
2931 | } |
2932 | /* |
2933 | * Since the runqueue lock will be released by the next |
2934 | * task (which is an invalid locking op but in the case |
2935 | * of the scheduler it's an obvious special-case), so we |
2936 | * do an early lockdep release here: |
2937 | */ |
2938 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
2939 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
2940 | #endif |
2941 | |
2942 | /* Here we just switch the register state and the stack. */ |
2943 | switch_to(prev, next, prev); |
2944 | |
2945 | barrier(); |
2946 | /* |
2947 | * this_rq must be evaluated again because prev may have moved |
2948 | * CPUs since it called schedule(), thus the 'rq' on its stack |
2949 | * frame will be invalid. |
2950 | */ |
2951 | finish_task_switch(this_rq(), prev); |
2952 | } |
2953 | |
2954 | /* |
2955 | * nr_running, nr_uninterruptible and nr_context_switches: |
2956 | * |
2957 | * externally visible scheduler statistics: current number of runnable |
2958 | * threads, current number of uninterruptible-sleeping threads, total |
2959 | * number of context switches performed since bootup. |
2960 | */ |
2961 | unsigned long nr_running(void) |
2962 | { |
2963 | unsigned long i, sum = 0; |
2964 | |
2965 | for_each_online_cpu(i) |
2966 | sum += cpu_rq(i)->nr_running; |
2967 | |
2968 | return sum; |
2969 | } |
2970 | |
2971 | unsigned long nr_uninterruptible(void) |
2972 | { |
2973 | unsigned long i, sum = 0; |
2974 | |
2975 | for_each_possible_cpu(i) |
2976 | sum += cpu_rq(i)->nr_uninterruptible; |
2977 | |
2978 | /* |
2979 | * Since we read the counters lockless, it might be slightly |
2980 | * inaccurate. Do not allow it to go below zero though: |
2981 | */ |
2982 | if (unlikely((long)sum < 0)) |
2983 | sum = 0; |
2984 | |
2985 | return sum; |
2986 | } |
2987 | |
2988 | unsigned long long nr_context_switches(void) |
2989 | { |
2990 | int i; |
2991 | unsigned long long sum = 0; |
2992 | |
2993 | for_each_possible_cpu(i) |
2994 | sum += cpu_rq(i)->nr_switches; |
2995 | |
2996 | return sum; |
2997 | } |
2998 | |
2999 | unsigned long nr_iowait(void) |
3000 | { |
3001 | unsigned long i, sum = 0; |
3002 | |
3003 | for_each_possible_cpu(i) |
3004 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
3005 | |
3006 | return sum; |
3007 | } |
3008 | |
3009 | unsigned long nr_iowait_cpu(void) |
3010 | { |
3011 | struct rq *this = this_rq(); |
3012 | return atomic_read(&this->nr_iowait); |
3013 | } |
3014 | |
3015 | unsigned long this_cpu_load(void) |
3016 | { |
3017 | struct rq *this = this_rq(); |
3018 | return this->cpu_load[0]; |
3019 | } |
3020 | |
3021 | |
3022 | /* Variables and functions for calc_load */ |
3023 | static atomic_long_t calc_load_tasks; |
3024 | static unsigned long calc_load_update; |
3025 | unsigned long avenrun[3]; |
3026 | EXPORT_SYMBOL(avenrun); |
3027 | |
3028 | /** |
3029 | * get_avenrun - get the load average array |
3030 | * @loads: pointer to dest load array |
3031 | * @offset: offset to add |
3032 | * @shift: shift count to shift the result left |
3033 | * |
3034 | * These values are estimates at best, so no need for locking. |
3035 | */ |
3036 | void get_avenrun(unsigned long *loads, unsigned long offset, int shift) |
3037 | { |
3038 | loads[0] = (avenrun[0] + offset) << shift; |
3039 | loads[1] = (avenrun[1] + offset) << shift; |
3040 | loads[2] = (avenrun[2] + offset) << shift; |
3041 | } |
3042 | |
3043 | static unsigned long |
3044 | calc_load(unsigned long load, unsigned long exp, unsigned long active) |
3045 | { |
3046 | load *= exp; |
3047 | load += active * (FIXED_1 - exp); |
3048 | return load >> FSHIFT; |
3049 | } |
3050 | |
3051 | /* |
3052 | * calc_load - update the avenrun load estimates 10 ticks after the |
3053 | * CPUs have updated calc_load_tasks. |
3054 | */ |
3055 | void calc_global_load(void) |
3056 | { |
3057 | unsigned long upd = calc_load_update + 10; |
3058 | long active; |
3059 | |
3060 | if (time_before(jiffies, upd)) |
3061 | return; |
3062 | |
3063 | active = atomic_long_read(&calc_load_tasks); |
3064 | active = active > 0 ? active * FIXED_1 : 0; |
3065 | |
3066 | avenrun[0] = calc_load(avenrun[0], EXP_1, active); |
3067 | avenrun[1] = calc_load(avenrun[1], EXP_5, active); |
3068 | avenrun[2] = calc_load(avenrun[2], EXP_15, active); |
3069 | |
3070 | calc_load_update += LOAD_FREQ; |
3071 | } |
3072 | |
3073 | /* |
3074 | * Either called from update_cpu_load() or from a cpu going idle |
3075 | */ |
3076 | static void calc_load_account_active(struct rq *this_rq) |
3077 | { |
3078 | long nr_active, delta; |
3079 | |
3080 | nr_active = this_rq->nr_running; |
3081 | nr_active += (long) this_rq->nr_uninterruptible; |
3082 | |
3083 | if (nr_active != this_rq->calc_load_active) { |
3084 | delta = nr_active - this_rq->calc_load_active; |
3085 | this_rq->calc_load_active = nr_active; |
3086 | atomic_long_add(delta, &calc_load_tasks); |
3087 | } |
3088 | } |
3089 | |
3090 | /* |
3091 | * Update rq->cpu_load[] statistics. This function is usually called every |
3092 | * scheduler tick (TICK_NSEC). |
3093 | */ |
3094 | static void update_cpu_load(struct rq *this_rq) |
3095 | { |
3096 | unsigned long this_load = this_rq->load.weight; |
3097 | int i, scale; |
3098 | |
3099 | this_rq->nr_load_updates++; |
3100 | |
3101 | /* Update our load: */ |
3102 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { |
3103 | unsigned long old_load, new_load; |
3104 | |
3105 | /* scale is effectively 1 << i now, and >> i divides by scale */ |
3106 | |
3107 | old_load = this_rq->cpu_load[i]; |
3108 | new_load = this_load; |
3109 | /* |
3110 | * Round up the averaging division if load is increasing. This |
3111 | * prevents us from getting stuck on 9 if the load is 10, for |
3112 | * example. |
3113 | */ |
3114 | if (new_load > old_load) |
3115 | new_load += scale-1; |
3116 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; |
3117 | } |
3118 | |
3119 | if (time_after_eq(jiffies, this_rq->calc_load_update)) { |
3120 | this_rq->calc_load_update += LOAD_FREQ; |
3121 | calc_load_account_active(this_rq); |
3122 | } |
3123 | } |
3124 | |
3125 | #ifdef CONFIG_SMP |
3126 | |
3127 | /* |
3128 | * sched_exec - execve() is a valuable balancing opportunity, because at |
3129 | * this point the task has the smallest effective memory and cache footprint. |
3130 | */ |
3131 | void sched_exec(void) |
3132 | { |
3133 | struct task_struct *p = current; |
3134 | struct migration_req req; |
3135 | int dest_cpu, this_cpu; |
3136 | unsigned long flags; |
3137 | struct rq *rq; |
3138 | |
3139 | again: |
3140 | this_cpu = get_cpu(); |
3141 | dest_cpu = select_task_rq(p, SD_BALANCE_EXEC, 0); |
3142 | if (dest_cpu == this_cpu) { |
3143 | put_cpu(); |
3144 | return; |
3145 | } |
3146 | |
3147 | rq = task_rq_lock(p, &flags); |
3148 | put_cpu(); |
3149 | |
3150 | /* |
3151 | * select_task_rq() can race against ->cpus_allowed |
3152 | */ |
3153 | if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed) |
3154 | || unlikely(!cpu_active(dest_cpu))) { |
3155 | task_rq_unlock(rq, &flags); |
3156 | goto again; |
3157 | } |
3158 | |
3159 | /* force the process onto the specified CPU */ |
3160 | if (migrate_task(p, dest_cpu, &req)) { |
3161 | /* Need to wait for migration thread (might exit: take ref). */ |
3162 | struct task_struct *mt = rq->migration_thread; |
3163 | |
3164 | get_task_struct(mt); |
3165 | task_rq_unlock(rq, &flags); |
3166 | wake_up_process(mt); |
3167 | put_task_struct(mt); |
3168 | wait_for_completion(&req.done); |
3169 | |
3170 | return; |
3171 | } |
3172 | task_rq_unlock(rq, &flags); |
3173 | } |
3174 | |
3175 | #endif |
3176 | |
3177 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3178 | |
3179 | EXPORT_PER_CPU_SYMBOL(kstat); |
3180 | |
3181 | /* |
3182 | * Return any ns on the sched_clock that have not yet been accounted in |
3183 | * @p in case that task is currently running. |
3184 | * |
3185 | * Called with task_rq_lock() held on @rq. |
3186 | */ |
3187 | static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) |
3188 | { |
3189 | u64 ns = 0; |
3190 | |
3191 | if (task_current(rq, p)) { |
3192 | update_rq_clock(rq); |
3193 | ns = rq->clock - p->se.exec_start; |
3194 | if ((s64)ns < 0) |
3195 | ns = 0; |
3196 | } |
3197 | |
3198 | return ns; |
3199 | } |
3200 | |
3201 | unsigned long long task_delta_exec(struct task_struct *p) |
3202 | { |
3203 | unsigned long flags; |
3204 | struct rq *rq; |
3205 | u64 ns = 0; |
3206 | |
3207 | rq = task_rq_lock(p, &flags); |
3208 | ns = do_task_delta_exec(p, rq); |
3209 | task_rq_unlock(rq, &flags); |
3210 | |
3211 | return ns; |
3212 | } |
3213 | |
3214 | /* |
3215 | * Return accounted runtime for the task. |
3216 | * In case the task is currently running, return the runtime plus current's |
3217 | * pending runtime that have not been accounted yet. |
3218 | */ |
3219 | unsigned long long task_sched_runtime(struct task_struct *p) |
3220 | { |
3221 | unsigned long flags; |
3222 | struct rq *rq; |
3223 | u64 ns = 0; |
3224 | |
3225 | rq = task_rq_lock(p, &flags); |
3226 | ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); |
3227 | task_rq_unlock(rq, &flags); |
3228 | |
3229 | return ns; |
3230 | } |
3231 | |
3232 | /* |
3233 | * Return sum_exec_runtime for the thread group. |
3234 | * In case the task is currently running, return the sum plus current's |
3235 | * pending runtime that have not been accounted yet. |
3236 | * |
3237 | * Note that the thread group might have other running tasks as well, |
3238 | * so the return value not includes other pending runtime that other |
3239 | * running tasks might have. |
3240 | */ |
3241 | unsigned long long thread_group_sched_runtime(struct task_struct *p) |
3242 | { |
3243 | struct task_cputime totals; |
3244 | unsigned long flags; |
3245 | struct rq *rq; |
3246 | u64 ns; |
3247 | |
3248 | rq = task_rq_lock(p, &flags); |
3249 | thread_group_cputime(p, &totals); |
3250 | ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq); |
3251 | task_rq_unlock(rq, &flags); |
3252 | |
3253 | return ns; |
3254 | } |
3255 | |
3256 | /* |
3257 | * Account user cpu time to a process. |
3258 | * @p: the process that the cpu time gets accounted to |
3259 | * @cputime: the cpu time spent in user space since the last update |
3260 | * @cputime_scaled: cputime scaled by cpu frequency |
3261 | */ |
3262 | void account_user_time(struct task_struct *p, cputime_t cputime, |
3263 | cputime_t cputime_scaled) |
3264 | { |
3265 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
3266 | cputime64_t tmp; |
3267 | |
3268 | /* Add user time to process. */ |
3269 | p->utime = cputime_add(p->utime, cputime); |
3270 | p->utimescaled = cputime_add(p->utimescaled, cputime_scaled); |
3271 | account_group_user_time(p, cputime); |
3272 | |
3273 | /* Add user time to cpustat. */ |
3274 | tmp = cputime_to_cputime64(cputime); |
3275 | if (TASK_NICE(p) > 0) |
3276 | cpustat->nice = cputime64_add(cpustat->nice, tmp); |
3277 | else |
3278 | cpustat->user = cputime64_add(cpustat->user, tmp); |
3279 | |
3280 | cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime); |
3281 | /* Account for user time used */ |
3282 | acct_update_integrals(p); |
3283 | } |
3284 | |
3285 | /* |
3286 | * Account guest cpu time to a process. |
3287 | * @p: the process that the cpu time gets accounted to |
3288 | * @cputime: the cpu time spent in virtual machine since the last update |
3289 | * @cputime_scaled: cputime scaled by cpu frequency |
3290 | */ |
3291 | static void account_guest_time(struct task_struct *p, cputime_t cputime, |
3292 | cputime_t cputime_scaled) |
3293 | { |
3294 | cputime64_t tmp; |
3295 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
3296 | |
3297 | tmp = cputime_to_cputime64(cputime); |
3298 | |
3299 | /* Add guest time to process. */ |
3300 | p->utime = cputime_add(p->utime, cputime); |
3301 | p->utimescaled = cputime_add(p->utimescaled, cputime_scaled); |
3302 | account_group_user_time(p, cputime); |
3303 | p->gtime = cputime_add(p->gtime, cputime); |
3304 | |
3305 | /* Add guest time to cpustat. */ |
3306 | if (TASK_NICE(p) > 0) { |
3307 | cpustat->nice = cputime64_add(cpustat->nice, tmp); |
3308 | cpustat->guest_nice = cputime64_add(cpustat->guest_nice, tmp); |
3309 | } else { |
3310 | cpustat->user = cputime64_add(cpustat->user, tmp); |
3311 | cpustat->guest = cputime64_add(cpustat->guest, tmp); |
3312 | } |
3313 | } |
3314 | |
3315 | /* |
3316 | * Account system cpu time to a process. |
3317 | * @p: the process that the cpu time gets accounted to |
3318 | * @hardirq_offset: the offset to subtract from hardirq_count() |
3319 | * @cputime: the cpu time spent in kernel space since the last update |
3320 | * @cputime_scaled: cputime scaled by cpu frequency |
3321 | */ |
3322 | void account_system_time(struct task_struct *p, int hardirq_offset, |
3323 | cputime_t cputime, cputime_t cputime_scaled) |
3324 | { |
3325 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
3326 | cputime64_t tmp; |
3327 | |
3328 | if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { |
3329 | account_guest_time(p, cputime, cputime_scaled); |
3330 | return; |
3331 | } |
3332 | |
3333 | /* Add system time to process. */ |
3334 | p->stime = cputime_add(p->stime, cputime); |
3335 | p->stimescaled = cputime_add(p->stimescaled, cputime_scaled); |
3336 | account_group_system_time(p, cputime); |
3337 | |
3338 | /* Add system time to cpustat. */ |
3339 | tmp = cputime_to_cputime64(cputime); |
3340 | if (hardirq_count() - hardirq_offset) |
3341 | cpustat->irq = cputime64_add(cpustat->irq, tmp); |
3342 | else if (softirq_count()) |
3343 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); |
3344 | else |
3345 | cpustat->system = cputime64_add(cpustat->system, tmp); |
3346 | |
3347 | cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime); |
3348 | |
3349 | /* Account for system time used */ |
3350 | acct_update_integrals(p); |
3351 | } |
3352 | |
3353 | /* |
3354 | * Account for involuntary wait time. |
3355 | * @steal: the cpu time spent in involuntary wait |
3356 | */ |
3357 | void account_steal_time(cputime_t cputime) |
3358 | { |
3359 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
3360 | cputime64_t cputime64 = cputime_to_cputime64(cputime); |
3361 | |
3362 | cpustat->steal = cputime64_add(cpustat->steal, cputime64); |
3363 | } |
3364 | |
3365 | /* |
3366 | * Account for idle time. |
3367 | * @cputime: the cpu time spent in idle wait |
3368 | */ |
3369 | void account_idle_time(cputime_t cputime) |
3370 | { |
3371 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
3372 | cputime64_t cputime64 = cputime_to_cputime64(cputime); |
3373 | struct rq *rq = this_rq(); |
3374 | |
3375 | if (atomic_read(&rq->nr_iowait) > 0) |
3376 | cpustat->iowait = cputime64_add(cpustat->iowait, cputime64); |
3377 | else |
3378 | cpustat->idle = cputime64_add(cpustat->idle, cputime64); |
3379 | } |
3380 | |
3381 | #ifndef CONFIG_VIRT_CPU_ACCOUNTING |
3382 | |
3383 | /* |
3384 | * Account a single tick of cpu time. |
3385 | * @p: the process that the cpu time gets accounted to |
3386 | * @user_tick: indicates if the tick is a user or a system tick |
3387 | */ |
3388 | void account_process_tick(struct task_struct *p, int user_tick) |
3389 | { |
3390 | cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); |
3391 | struct rq *rq = this_rq(); |
3392 | |
3393 | if (user_tick) |
3394 | account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); |
3395 | else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) |
3396 | account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, |
3397 | one_jiffy_scaled); |
3398 | else |
3399 | account_idle_time(cputime_one_jiffy); |
3400 | } |
3401 | |
3402 | /* |
3403 | * Account multiple ticks of steal time. |
3404 | * @p: the process from which the cpu time has been stolen |
3405 | * @ticks: number of stolen ticks |
3406 | */ |
3407 | void account_steal_ticks(unsigned long ticks) |
3408 | { |
3409 | account_steal_time(jiffies_to_cputime(ticks)); |
3410 | } |
3411 | |
3412 | /* |
3413 | * Account multiple ticks of idle time. |
3414 | * @ticks: number of stolen ticks |
3415 | */ |
3416 | void account_idle_ticks(unsigned long ticks) |
3417 | { |
3418 | account_idle_time(jiffies_to_cputime(ticks)); |
3419 | } |
3420 | |
3421 | #endif |
3422 | |
3423 | /* |
3424 | * Use precise platform statistics if available: |
3425 | */ |
3426 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING |
3427 | void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) |
3428 | { |
3429 | *ut = p->utime; |
3430 | *st = p->stime; |
3431 | } |
3432 | |
3433 | void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) |
3434 | { |
3435 | struct task_cputime cputime; |
3436 | |
3437 | thread_group_cputime(p, &cputime); |
3438 | |
3439 | *ut = cputime.utime; |
3440 | *st = cputime.stime; |
3441 | } |
3442 | #else |
3443 | |
3444 | #ifndef nsecs_to_cputime |
3445 | # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs) |
3446 | #endif |
3447 | |
3448 | void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) |
3449 | { |
3450 | cputime_t rtime, utime = p->utime, total = cputime_add(utime, p->stime); |
3451 | |
3452 | /* |
3453 | * Use CFS's precise accounting: |
3454 | */ |
3455 | rtime = nsecs_to_cputime(p->se.sum_exec_runtime); |
3456 | |
3457 | if (total) { |
3458 | u64 temp; |
3459 | |
3460 | temp = (u64)(rtime * utime); |
3461 | do_div(temp, total); |
3462 | utime = (cputime_t)temp; |
3463 | } else |
3464 | utime = rtime; |
3465 | |
3466 | /* |
3467 | * Compare with previous values, to keep monotonicity: |
3468 | */ |
3469 | p->prev_utime = max(p->prev_utime, utime); |
3470 | p->prev_stime = max(p->prev_stime, cputime_sub(rtime, p->prev_utime)); |
3471 | |
3472 | *ut = p->prev_utime; |
3473 | *st = p->prev_stime; |
3474 | } |
3475 | |
3476 | /* |
3477 | * Must be called with siglock held. |
3478 | */ |
3479 | void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) |
3480 | { |
3481 | struct signal_struct *sig = p->signal; |
3482 | struct task_cputime cputime; |
3483 | cputime_t rtime, utime, total; |
3484 | |
3485 | thread_group_cputime(p, &cputime); |
3486 | |
3487 | total = cputime_add(cputime.utime, cputime.stime); |
3488 | rtime = nsecs_to_cputime(cputime.sum_exec_runtime); |
3489 | |
3490 | if (total) { |
3491 | u64 temp; |
3492 | |
3493 | temp = (u64)(rtime * cputime.utime); |
3494 | do_div(temp, total); |
3495 | utime = (cputime_t)temp; |
3496 | } else |
3497 | utime = rtime; |
3498 | |
3499 | sig->prev_utime = max(sig->prev_utime, utime); |
3500 | sig->prev_stime = max(sig->prev_stime, |
3501 | cputime_sub(rtime, sig->prev_utime)); |
3502 | |
3503 | *ut = sig->prev_utime; |
3504 | *st = sig->prev_stime; |
3505 | } |
3506 | #endif |
3507 | |
3508 | /* |
3509 | * This function gets called by the timer code, with HZ frequency. |
3510 | * We call it with interrupts disabled. |
3511 | * |
3512 | * It also gets called by the fork code, when changing the parent's |
3513 | * timeslices. |
3514 | */ |
3515 | void scheduler_tick(void) |
3516 | { |
3517 | int cpu = smp_processor_id(); |
3518 | struct rq *rq = cpu_rq(cpu); |
3519 | struct task_struct *curr = rq->curr; |
3520 | |
3521 | sched_clock_tick(); |
3522 | |
3523 | raw_spin_lock(&rq->lock); |
3524 | update_rq_clock(rq); |
3525 | update_cpu_load(rq); |
3526 | curr->sched_class->task_tick(rq, curr, 0); |
3527 | raw_spin_unlock(&rq->lock); |
3528 | |
3529 | perf_event_task_tick(curr); |
3530 | |
3531 | #ifdef CONFIG_SMP |
3532 | rq->idle_at_tick = idle_cpu(cpu); |
3533 | trigger_load_balance(rq, cpu); |
3534 | #endif |
3535 | } |
3536 | |
3537 | notrace unsigned long get_parent_ip(unsigned long addr) |
3538 | { |
3539 | if (in_lock_functions(addr)) { |
3540 | addr = CALLER_ADDR2; |
3541 | if (in_lock_functions(addr)) |
3542 | addr = CALLER_ADDR3; |
3543 | } |
3544 | return addr; |
3545 | } |
3546 | |
3547 | #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ |
3548 | defined(CONFIG_PREEMPT_TRACER)) |
3549 | |
3550 | void __kprobes add_preempt_count(int val) |
3551 | { |
3552 | #ifdef CONFIG_DEBUG_PREEMPT |
3553 | /* |
3554 | * Underflow? |
3555 | */ |
3556 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3557 | return; |
3558 | #endif |
3559 | preempt_count() += val; |
3560 | #ifdef CONFIG_DEBUG_PREEMPT |
3561 | /* |
3562 | * Spinlock count overflowing soon? |
3563 | */ |
3564 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3565 | PREEMPT_MASK - 10); |
3566 | #endif |
3567 | if (preempt_count() == val) |
3568 | trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); |
3569 | } |
3570 | EXPORT_SYMBOL(add_preempt_count); |
3571 | |
3572 | void __kprobes sub_preempt_count(int val) |
3573 | { |
3574 | #ifdef CONFIG_DEBUG_PREEMPT |
3575 | /* |
3576 | * Underflow? |
3577 | */ |
3578 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3579 | return; |
3580 | /* |
3581 | * Is the spinlock portion underflowing? |
3582 | */ |
3583 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3584 | !(preempt_count() & PREEMPT_MASK))) |
3585 | return; |
3586 | #endif |
3587 | |
3588 | if (preempt_count() == val) |
3589 | trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); |
3590 | preempt_count() -= val; |
3591 | } |
3592 | EXPORT_SYMBOL(sub_preempt_count); |
3593 | |
3594 | #endif |
3595 | |
3596 | /* |
3597 | * Print scheduling while atomic bug: |
3598 | */ |
3599 | static noinline void __schedule_bug(struct task_struct *prev) |
3600 | { |
3601 | struct pt_regs *regs = get_irq_regs(); |
3602 | |
3603 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", |
3604 | prev->comm, prev->pid, preempt_count()); |
3605 | |
3606 | debug_show_held_locks(prev); |
3607 | print_modules(); |
3608 | if (irqs_disabled()) |
3609 | print_irqtrace_events(prev); |
3610 | |
3611 | if (regs) |
3612 | show_regs(regs); |
3613 | else |
3614 | dump_stack(); |
3615 | } |
3616 | |
3617 | /* |
3618 | * Various schedule()-time debugging checks and statistics: |
3619 | */ |
3620 | static inline void schedule_debug(struct task_struct *prev) |
3621 | { |
3622 | /* |
3623 | * Test if we are atomic. Since do_exit() needs to call into |
3624 | * schedule() atomically, we ignore that path for now. |
3625 | * Otherwise, whine if we are scheduling when we should not be. |
3626 | */ |
3627 | if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) |
3628 | __schedule_bug(prev); |
3629 | |
3630 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3631 | |
3632 | schedstat_inc(this_rq(), sched_count); |
3633 | #ifdef CONFIG_SCHEDSTATS |
3634 | if (unlikely(prev->lock_depth >= 0)) { |
3635 | schedstat_inc(this_rq(), bkl_count); |
3636 | schedstat_inc(prev, sched_info.bkl_count); |
3637 | } |
3638 | #endif |
3639 | } |
3640 | |
3641 | static void put_prev_task(struct rq *rq, struct task_struct *prev) |
3642 | { |
3643 | if (prev->state == TASK_RUNNING) { |
3644 | u64 runtime = prev->se.sum_exec_runtime; |
3645 | |
3646 | runtime -= prev->se.prev_sum_exec_runtime; |
3647 | runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost); |
3648 | |
3649 | /* |
3650 | * In order to avoid avg_overlap growing stale when we are |
3651 | * indeed overlapping and hence not getting put to sleep, grow |
3652 | * the avg_overlap on preemption. |
3653 | * |
3654 | * We use the average preemption runtime because that |
3655 | * correlates to the amount of cache footprint a task can |
3656 | * build up. |
3657 | */ |
3658 | update_avg(&prev->se.avg_overlap, runtime); |
3659 | } |
3660 | prev->sched_class->put_prev_task(rq, prev); |
3661 | } |
3662 | |
3663 | /* |
3664 | * Pick up the highest-prio task: |
3665 | */ |
3666 | static inline struct task_struct * |
3667 | pick_next_task(struct rq *rq) |
3668 | { |
3669 | const struct sched_class *class; |
3670 | struct task_struct *p; |
3671 | |
3672 | /* |
3673 | * Optimization: we know that if all tasks are in |
3674 | * the fair class we can call that function directly: |
3675 | */ |
3676 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
3677 | p = fair_sched_class.pick_next_task(rq); |
3678 | if (likely(p)) |
3679 | return p; |
3680 | } |
3681 | |
3682 | class = sched_class_highest; |
3683 | for ( ; ; ) { |
3684 | p = class->pick_next_task(rq); |
3685 | if (p) |
3686 | return p; |
3687 | /* |
3688 | * Will never be NULL as the idle class always |
3689 | * returns a non-NULL p: |
3690 | */ |
3691 | class = class->next; |
3692 | } |
3693 | } |
3694 | |
3695 | /* |
3696 | * schedule() is the main scheduler function. |
3697 | */ |
3698 | asmlinkage void __sched schedule(void) |
3699 | { |
3700 | struct task_struct *prev, *next; |
3701 | unsigned long *switch_count; |
3702 | struct rq *rq; |
3703 | int cpu; |
3704 | |
3705 | need_resched: |
3706 | preempt_disable(); |
3707 | cpu = smp_processor_id(); |
3708 | rq = cpu_rq(cpu); |
3709 | rcu_sched_qs(cpu); |
3710 | prev = rq->curr; |
3711 | switch_count = &prev->nivcsw; |
3712 | |
3713 | release_kernel_lock(prev); |
3714 | need_resched_nonpreemptible: |
3715 | |
3716 | schedule_debug(prev); |
3717 | |
3718 | if (sched_feat(HRTICK)) |
3719 | hrtick_clear(rq); |
3720 | |
3721 | raw_spin_lock_irq(&rq->lock); |
3722 | update_rq_clock(rq); |
3723 | clear_tsk_need_resched(prev); |
3724 | |
3725 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
3726 | if (unlikely(signal_pending_state(prev->state, prev))) |
3727 | prev->state = TASK_RUNNING; |
3728 | else |
3729 | deactivate_task(rq, prev, 1); |
3730 | switch_count = &prev->nvcsw; |
3731 | } |
3732 | |
3733 | pre_schedule(rq, prev); |
3734 | |
3735 | if (unlikely(!rq->nr_running)) |
3736 | idle_balance(cpu, rq); |
3737 | |
3738 | put_prev_task(rq, prev); |
3739 | next = pick_next_task(rq); |
3740 | |
3741 | if (likely(prev != next)) { |
3742 | sched_info_switch(prev, next); |
3743 | perf_event_task_sched_out(prev, next); |
3744 | |
3745 | rq->nr_switches++; |
3746 | rq->curr = next; |
3747 | ++*switch_count; |
3748 | |
3749 | context_switch(rq, prev, next); /* unlocks the rq */ |
3750 | /* |
3751 | * the context switch might have flipped the stack from under |
3752 | * us, hence refresh the local variables. |
3753 | */ |
3754 | cpu = smp_processor_id(); |
3755 | rq = cpu_rq(cpu); |
3756 | } else |
3757 | raw_spin_unlock_irq(&rq->lock); |
3758 | |
3759 | post_schedule(rq); |
3760 | |
3761 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
3762 | prev = rq->curr; |
3763 | switch_count = &prev->nivcsw; |
3764 | goto need_resched_nonpreemptible; |
3765 | } |
3766 | |
3767 | preempt_enable_no_resched(); |
3768 | if (need_resched()) |
3769 | goto need_resched; |
3770 | } |
3771 | EXPORT_SYMBOL(schedule); |
3772 | |
3773 | #ifdef CONFIG_MUTEX_SPIN_ON_OWNER |
3774 | /* |
3775 | * Look out! "owner" is an entirely speculative pointer |
3776 | * access and not reliable. |
3777 | */ |
3778 | int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner) |
3779 | { |
3780 | unsigned int cpu; |
3781 | struct rq *rq; |
3782 | |
3783 | if (!sched_feat(OWNER_SPIN)) |
3784 | return 0; |
3785 | |
3786 | #ifdef CONFIG_DEBUG_PAGEALLOC |
3787 | /* |
3788 | * Need to access the cpu field knowing that |
3789 | * DEBUG_PAGEALLOC could have unmapped it if |
3790 | * the mutex owner just released it and exited. |
3791 | */ |
3792 | if (probe_kernel_address(&owner->cpu, cpu)) |
3793 | return 0; |
3794 | #else |
3795 | cpu = owner->cpu; |
3796 | #endif |
3797 | |
3798 | /* |
3799 | * Even if the access succeeded (likely case), |
3800 | * the cpu field may no longer be valid. |
3801 | */ |
3802 | if (cpu >= nr_cpumask_bits) |
3803 | return 0; |
3804 | |
3805 | /* |
3806 | * We need to validate that we can do a |
3807 | * get_cpu() and that we have the percpu area. |
3808 | */ |
3809 | if (!cpu_online(cpu)) |
3810 | return 0; |
3811 | |
3812 | rq = cpu_rq(cpu); |
3813 | |
3814 | for (;;) { |
3815 | /* |
3816 | * Owner changed, break to re-assess state. |
3817 | */ |
3818 | if (lock->owner != owner) |
3819 | break; |
3820 | |
3821 | /* |
3822 | * Is that owner really running on that cpu? |
3823 | */ |
3824 | if (task_thread_info(rq->curr) != owner || need_resched()) |
3825 | return 0; |
3826 | |
3827 | cpu_relax(); |
3828 | } |
3829 | |
3830 | return 1; |
3831 | } |
3832 | #endif |
3833 | |
3834 | #ifdef CONFIG_PREEMPT |
3835 | /* |
3836 | * this is the entry point to schedule() from in-kernel preemption |
3837 | * off of preempt_enable. Kernel preemptions off return from interrupt |
3838 | * occur there and call schedule directly. |
3839 | */ |
3840 | asmlinkage void __sched preempt_schedule(void) |
3841 | { |
3842 | struct thread_info *ti = current_thread_info(); |
3843 | |
3844 | /* |
3845 | * If there is a non-zero preempt_count or interrupts are disabled, |
3846 | * we do not want to preempt the current task. Just return.. |
3847 | */ |
3848 | if (likely(ti->preempt_count || irqs_disabled())) |
3849 | return; |
3850 | |
3851 | do { |
3852 | add_preempt_count(PREEMPT_ACTIVE); |
3853 | schedule(); |
3854 | sub_preempt_count(PREEMPT_ACTIVE); |
3855 | |
3856 | /* |
3857 | * Check again in case we missed a preemption opportunity |
3858 | * between schedule and now. |
3859 | */ |
3860 | barrier(); |
3861 | } while (need_resched()); |
3862 | } |
3863 | EXPORT_SYMBOL(preempt_schedule); |
3864 | |
3865 | /* |
3866 | * this is the entry point to schedule() from kernel preemption |
3867 | * off of irq context. |
3868 | * Note, that this is called and return with irqs disabled. This will |
3869 | * protect us against recursive calling from irq. |
3870 | */ |
3871 | asmlinkage void __sched preempt_schedule_irq(void) |
3872 | { |
3873 | struct thread_info *ti = current_thread_info(); |
3874 | |
3875 | /* Catch callers which need to be fixed */ |
3876 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
3877 | |
3878 | do { |
3879 | add_preempt_count(PREEMPT_ACTIVE); |
3880 | local_irq_enable(); |
3881 | schedule(); |
3882 | local_irq_disable(); |
3883 | sub_preempt_count(PREEMPT_ACTIVE); |
3884 | |
3885 | /* |
3886 | * Check again in case we missed a preemption opportunity |
3887 | * between schedule and now. |
3888 | */ |
3889 | barrier(); |
3890 | } while (need_resched()); |
3891 | } |
3892 | |
3893 | #endif /* CONFIG_PREEMPT */ |
3894 | |
3895 | int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, |
3896 | void *key) |
3897 | { |
3898 | return try_to_wake_up(curr->private, mode, wake_flags); |
3899 | } |
3900 | EXPORT_SYMBOL(default_wake_function); |
3901 | |
3902 | /* |
3903 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
3904 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve |
3905 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
3906 | * |
3907 | * There are circumstances in which we can try to wake a task which has already |
3908 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
3909 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
3910 | */ |
3911 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, |
3912 | int nr_exclusive, int wake_flags, void *key) |
3913 | { |
3914 | wait_queue_t *curr, *next; |
3915 | |
3916 | list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
3917 | unsigned flags = curr->flags; |
3918 | |
3919 | if (curr->func(curr, mode, wake_flags, key) && |
3920 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
3921 | break; |
3922 | } |
3923 | } |
3924 | |
3925 | /** |
3926 | * __wake_up - wake up threads blocked on a waitqueue. |
3927 | * @q: the waitqueue |
3928 | * @mode: which threads |
3929 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
3930 | * @key: is directly passed to the wakeup function |
3931 | * |
3932 | * It may be assumed that this function implies a write memory barrier before |
3933 | * changing the task state if and only if any tasks are woken up. |
3934 | */ |
3935 | void __wake_up(wait_queue_head_t *q, unsigned int mode, |
3936 | int nr_exclusive, void *key) |
3937 | { |
3938 | unsigned long flags; |
3939 | |
3940 | spin_lock_irqsave(&q->lock, flags); |
3941 | __wake_up_common(q, mode, nr_exclusive, 0, key); |
3942 | spin_unlock_irqrestore(&q->lock, flags); |
3943 | } |
3944 | EXPORT_SYMBOL(__wake_up); |
3945 | |
3946 | /* |
3947 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. |
3948 | */ |
3949 | void __wake_up_locked(wait_queue_head_t *q, unsigned int mode) |
3950 | { |
3951 | __wake_up_common(q, mode, 1, 0, NULL); |
3952 | } |
3953 | |
3954 | void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) |
3955 | { |
3956 | __wake_up_common(q, mode, 1, 0, key); |
3957 | } |
3958 | |
3959 | /** |
3960 | * __wake_up_sync_key - wake up threads blocked on a waitqueue. |
3961 | * @q: the waitqueue |
3962 | * @mode: which threads |
3963 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
3964 | * @key: opaque value to be passed to wakeup targets |
3965 | * |
3966 | * The sync wakeup differs that the waker knows that it will schedule |
3967 | * away soon, so while the target thread will be woken up, it will not |
3968 | * be migrated to another CPU - ie. the two threads are 'synchronized' |
3969 | * with each other. This can prevent needless bouncing between CPUs. |
3970 | * |
3971 | * On UP it can prevent extra preemption. |
3972 | * |
3973 | * It may be assumed that this function implies a write memory barrier before |
3974 | * changing the task state if and only if any tasks are woken up. |
3975 | */ |
3976 | void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, |
3977 | int nr_exclusive, void *key) |
3978 | { |
3979 | unsigned long flags; |
3980 | int wake_flags = WF_SYNC; |
3981 | |
3982 | if (unlikely(!q)) |
3983 | return; |
3984 | |
3985 | if (unlikely(!nr_exclusive)) |
3986 | wake_flags = 0; |
3987 | |
3988 | spin_lock_irqsave(&q->lock, flags); |
3989 | __wake_up_common(q, mode, nr_exclusive, wake_flags, key); |
3990 | spin_unlock_irqrestore(&q->lock, flags); |
3991 | } |
3992 | EXPORT_SYMBOL_GPL(__wake_up_sync_key); |
3993 | |
3994 | /* |
3995 | * __wake_up_sync - see __wake_up_sync_key() |
3996 | */ |
3997 | void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) |
3998 | { |
3999 | __wake_up_sync_key(q, mode, nr_exclusive, NULL); |
4000 | } |
4001 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ |
4002 | |
4003 | /** |
4004 | * complete: - signals a single thread waiting on this completion |
4005 | * @x: holds the state of this particular completion |
4006 | * |
4007 | * This will wake up a single thread waiting on this completion. Threads will be |
4008 | * awakened in the same order in which they were queued. |
4009 | * |
4010 | * See also complete_all(), wait_for_completion() and related routines. |
4011 | * |
4012 | * It may be assumed that this function implies a write memory barrier before |
4013 | * changing the task state if and only if any tasks are woken up. |
4014 | */ |
4015 | void complete(struct completion *x) |
4016 | { |
4017 | unsigned long flags; |
4018 | |
4019 | spin_lock_irqsave(&x->wait.lock, flags); |
4020 | x->done++; |
4021 | __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); |
4022 | spin_unlock_irqrestore(&x->wait.lock, flags); |
4023 | } |
4024 | EXPORT_SYMBOL(complete); |
4025 | |
4026 | /** |
4027 | * complete_all: - signals all threads waiting on this completion |
4028 | * @x: holds the state of this particular completion |
4029 | * |
4030 | * This will wake up all threads waiting on this particular completion event. |
4031 | * |
4032 | * It may be assumed that this function implies a write memory barrier before |
4033 | * changing the task state if and only if any tasks are woken up. |
4034 | */ |
4035 | void complete_all(struct completion *x) |
4036 | { |
4037 | unsigned long flags; |
4038 | |
4039 | spin_lock_irqsave(&x->wait.lock, flags); |
4040 | x->done += UINT_MAX/2; |
4041 | __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); |
4042 | spin_unlock_irqrestore(&x->wait.lock, flags); |
4043 | } |
4044 | EXPORT_SYMBOL(complete_all); |
4045 | |
4046 | static inline long __sched |
4047 | do_wait_for_common(struct completion *x, long timeout, int state) |
4048 | { |
4049 | if (!x->done) { |
4050 | DECLARE_WAITQUEUE(wait, current); |
4051 | |
4052 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
4053 | __add_wait_queue_tail(&x->wait, &wait); |
4054 | do { |
4055 | if (signal_pending_state(state, current)) { |
4056 | timeout = -ERESTARTSYS; |
4057 | break; |
4058 | } |
4059 | __set_current_state(state); |
4060 | spin_unlock_irq(&x->wait.lock); |
4061 | timeout = schedule_timeout(timeout); |
4062 | spin_lock_irq(&x->wait.lock); |
4063 | } while (!x->done && timeout); |
4064 | __remove_wait_queue(&x->wait, &wait); |
4065 | if (!x->done) |
4066 | return timeout; |
4067 | } |
4068 | x->done--; |
4069 | return timeout ?: 1; |
4070 | } |
4071 | |
4072 | static long __sched |
4073 | wait_for_common(struct completion *x, long timeout, int state) |
4074 | { |
4075 | might_sleep(); |
4076 | |
4077 | spin_lock_irq(&x->wait.lock); |
4078 | timeout = do_wait_for_common(x, timeout, state); |
4079 | spin_unlock_irq(&x->wait.lock); |
4080 | return timeout; |
4081 | } |
4082 | |
4083 | /** |
4084 | * wait_for_completion: - waits for completion of a task |
4085 | * @x: holds the state of this particular completion |
4086 | * |
4087 | * This waits to be signaled for completion of a specific task. It is NOT |
4088 | * interruptible and there is no timeout. |
4089 | * |
4090 | * See also similar routines (i.e. wait_for_completion_timeout()) with timeout |
4091 | * and interrupt capability. Also see complete(). |
4092 | */ |
4093 | void __sched wait_for_completion(struct completion *x) |
4094 | { |
4095 | wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); |
4096 | } |
4097 | EXPORT_SYMBOL(wait_for_completion); |
4098 | |
4099 | /** |
4100 | * wait_for_completion_timeout: - waits for completion of a task (w/timeout) |
4101 | * @x: holds the state of this particular completion |
4102 | * @timeout: timeout value in jiffies |
4103 | * |
4104 | * This waits for either a completion of a specific task to be signaled or for a |
4105 | * specified timeout to expire. The timeout is in jiffies. It is not |
4106 | * interruptible. |
4107 | */ |
4108 | unsigned long __sched |
4109 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
4110 | { |
4111 | return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
4112 | } |
4113 | EXPORT_SYMBOL(wait_for_completion_timeout); |
4114 | |
4115 | /** |
4116 | * wait_for_completion_interruptible: - waits for completion of a task (w/intr) |
4117 | * @x: holds the state of this particular completion |
4118 | * |
4119 | * This waits for completion of a specific task to be signaled. It is |
4120 | * interruptible. |
4121 | */ |
4122 | int __sched wait_for_completion_interruptible(struct completion *x) |
4123 | { |
4124 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
4125 | if (t == -ERESTARTSYS) |
4126 | return t; |
4127 | return 0; |
4128 | } |
4129 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
4130 | |
4131 | /** |
4132 | * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) |
4133 | * @x: holds the state of this particular completion |
4134 | * @timeout: timeout value in jiffies |
4135 | * |
4136 | * This waits for either a completion of a specific task to be signaled or for a |
4137 | * specified timeout to expire. It is interruptible. The timeout is in jiffies. |
4138 | */ |
4139 | unsigned long __sched |
4140 | wait_for_completion_interruptible_timeout(struct completion *x, |
4141 | unsigned long timeout) |
4142 | { |
4143 | return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
4144 | } |
4145 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
4146 | |
4147 | /** |
4148 | * wait_for_completion_killable: - waits for completion of a task (killable) |
4149 | * @x: holds the state of this particular completion |
4150 | * |
4151 | * This waits to be signaled for completion of a specific task. It can be |
4152 | * interrupted by a kill signal. |
4153 | */ |
4154 | int __sched wait_for_completion_killable(struct completion *x) |
4155 | { |
4156 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); |
4157 | if (t == -ERESTARTSYS) |
4158 | return t; |
4159 | return 0; |
4160 | } |
4161 | EXPORT_SYMBOL(wait_for_completion_killable); |
4162 | |
4163 | /** |
4164 | * try_wait_for_completion - try to decrement a completion without blocking |
4165 | * @x: completion structure |
4166 | * |
4167 | * Returns: 0 if a decrement cannot be done without blocking |
4168 | * 1 if a decrement succeeded. |
4169 | * |
4170 | * If a completion is being used as a counting completion, |
4171 | * attempt to decrement the counter without blocking. This |
4172 | * enables us to avoid waiting if the resource the completion |
4173 | * is protecting is not available. |
4174 | */ |
4175 | bool try_wait_for_completion(struct completion *x) |
4176 | { |
4177 | unsigned long flags; |
4178 | int ret = 1; |
4179 | |
4180 | spin_lock_irqsave(&x->wait.lock, flags); |
4181 | if (!x->done) |
4182 | ret = 0; |
4183 | else |
4184 | x->done--; |
4185 | spin_unlock_irqrestore(&x->wait.lock, flags); |
4186 | return ret; |
4187 | } |
4188 | EXPORT_SYMBOL(try_wait_for_completion); |
4189 | |
4190 | /** |
4191 | * completion_done - Test to see if a completion has any waiters |
4192 | * @x: completion structure |
4193 | * |
4194 | * Returns: 0 if there are waiters (wait_for_completion() in progress) |
4195 | * 1 if there are no waiters. |
4196 | * |
4197 | */ |
4198 | bool completion_done(struct completion *x) |
4199 | { |
4200 | unsigned long flags; |
4201 | int ret = 1; |
4202 | |
4203 | spin_lock_irqsave(&x->wait.lock, flags); |
4204 | if (!x->done) |
4205 | ret = 0; |
4206 | spin_unlock_irqrestore(&x->wait.lock, flags); |
4207 | return ret; |
4208 | } |
4209 | EXPORT_SYMBOL(completion_done); |
4210 | |
4211 | static long __sched |
4212 | sleep_on_common(wait_queue_head_t *q, int state, long timeout) |
4213 | { |
4214 | unsigned long flags; |
4215 | wait_queue_t wait; |
4216 | |
4217 | init_waitqueue_entry(&wait, current); |
4218 | |
4219 | __set_current_state(state); |
4220 | |
4221 | spin_lock_irqsave(&q->lock, flags); |
4222 | __add_wait_queue(q, &wait); |
4223 | spin_unlock(&q->lock); |
4224 | timeout = schedule_timeout(timeout); |
4225 | spin_lock_irq(&q->lock); |
4226 | __remove_wait_queue(q, &wait); |
4227 | spin_unlock_irqrestore(&q->lock, flags); |
4228 | |
4229 | return timeout; |
4230 | } |
4231 | |
4232 | void __sched interruptible_sleep_on(wait_queue_head_t *q) |
4233 | { |
4234 | sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
4235 | } |
4236 | EXPORT_SYMBOL(interruptible_sleep_on); |
4237 | |
4238 | long __sched |
4239 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
4240 | { |
4241 | return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
4242 | } |
4243 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
4244 | |
4245 | void __sched sleep_on(wait_queue_head_t *q) |
4246 | { |
4247 | sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
4248 | } |
4249 | EXPORT_SYMBOL(sleep_on); |
4250 | |
4251 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
4252 | { |
4253 | return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
4254 | } |
4255 | EXPORT_SYMBOL(sleep_on_timeout); |
4256 | |
4257 | #ifdef CONFIG_RT_MUTEXES |
4258 | |
4259 | /* |
4260 | * rt_mutex_setprio - set the current priority of a task |
4261 | * @p: task |
4262 | * @prio: prio value (kernel-internal form) |
4263 | * |
4264 | * This function changes the 'effective' priority of a task. It does |
4265 | * not touch ->normal_prio like __setscheduler(). |
4266 | * |
4267 | * Used by the rt_mutex code to implement priority inheritance logic. |
4268 | */ |
4269 | void rt_mutex_setprio(struct task_struct *p, int prio) |
4270 | { |
4271 | unsigned long flags; |
4272 | int oldprio, on_rq, running; |
4273 | struct rq *rq; |
4274 | const struct sched_class *prev_class; |
4275 | |
4276 | BUG_ON(prio < 0 || prio > MAX_PRIO); |
4277 | |
4278 | rq = task_rq_lock(p, &flags); |
4279 | update_rq_clock(rq); |
4280 | |
4281 | oldprio = p->prio; |
4282 | prev_class = p->sched_class; |
4283 | on_rq = p->se.on_rq; |
4284 | running = task_current(rq, p); |
4285 | if (on_rq) |
4286 | dequeue_task(rq, p, 0); |
4287 | if (running) |
4288 | p->sched_class->put_prev_task(rq, p); |
4289 | |
4290 | if (rt_prio(prio)) |
4291 | p->sched_class = &rt_sched_class; |
4292 | else |
4293 | p->sched_class = &fair_sched_class; |
4294 | |
4295 | p->prio = prio; |
4296 | |
4297 | if (running) |
4298 | p->sched_class->set_curr_task(rq); |
4299 | if (on_rq) { |
4300 | enqueue_task(rq, p, 0, oldprio < prio); |
4301 | |
4302 | check_class_changed(rq, p, prev_class, oldprio, running); |
4303 | } |
4304 | task_rq_unlock(rq, &flags); |
4305 | } |
4306 | |
4307 | #endif |
4308 | |
4309 | void set_user_nice(struct task_struct *p, long nice) |
4310 | { |
4311 | int old_prio, delta, on_rq; |
4312 | unsigned long flags; |
4313 | struct rq *rq; |
4314 | |
4315 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) |
4316 | return; |
4317 | /* |
4318 | * We have to be careful, if called from sys_setpriority(), |
4319 | * the task might be in the middle of scheduling on another CPU. |
4320 | */ |
4321 | rq = task_rq_lock(p, &flags); |
4322 | update_rq_clock(rq); |
4323 | /* |
4324 | * The RT priorities are set via sched_setscheduler(), but we still |
4325 | * allow the 'normal' nice value to be set - but as expected |
4326 | * it wont have any effect on scheduling until the task is |
4327 | * SCHED_FIFO/SCHED_RR: |
4328 | */ |
4329 | if (task_has_rt_policy(p)) { |
4330 | p->static_prio = NICE_TO_PRIO(nice); |
4331 | goto out_unlock; |
4332 | } |
4333 | on_rq = p->se.on_rq; |
4334 | if (on_rq) |
4335 | dequeue_task(rq, p, 0); |
4336 | |
4337 | p->static_prio = NICE_TO_PRIO(nice); |
4338 | set_load_weight(p); |
4339 | old_prio = p->prio; |
4340 | p->prio = effective_prio(p); |
4341 | delta = p->prio - old_prio; |
4342 | |
4343 | if (on_rq) { |
4344 | enqueue_task(rq, p, 0, false); |
4345 | /* |
4346 | * If the task increased its priority or is running and |
4347 | * lowered its priority, then reschedule its CPU: |
4348 | */ |
4349 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
4350 | resched_task(rq->curr); |
4351 | } |
4352 | out_unlock: |
4353 | task_rq_unlock(rq, &flags); |
4354 | } |
4355 | EXPORT_SYMBOL(set_user_nice); |
4356 | |
4357 | /* |
4358 | * can_nice - check if a task can reduce its nice value |
4359 | * @p: task |
4360 | * @nice: nice value |
4361 | */ |
4362 | int can_nice(const struct task_struct *p, const int nice) |
4363 | { |
4364 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
4365 | int nice_rlim = 20 - nice; |
4366 | |
4367 | return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || |
4368 | capable(CAP_SYS_NICE)); |
4369 | } |
4370 | |
4371 | #ifdef __ARCH_WANT_SYS_NICE |
4372 | |
4373 | /* |
4374 | * sys_nice - change the priority of the current process. |
4375 | * @increment: priority increment |
4376 | * |
4377 | * sys_setpriority is a more generic, but much slower function that |
4378 | * does similar things. |
4379 | */ |
4380 | SYSCALL_DEFINE1(nice, int, increment) |
4381 | { |
4382 | long nice, retval; |
4383 | |
4384 | /* |
4385 | * Setpriority might change our priority at the same moment. |
4386 | * We don't have to worry. Conceptually one call occurs first |
4387 | * and we have a single winner. |
4388 | */ |
4389 | if (increment < -40) |
4390 | increment = -40; |
4391 | if (increment > 40) |
4392 | increment = 40; |
4393 | |
4394 | nice = TASK_NICE(current) + increment; |
4395 | if (nice < -20) |
4396 | nice = -20; |
4397 | if (nice > 19) |
4398 | nice = 19; |
4399 | |
4400 | if (increment < 0 && !can_nice(current, nice)) |
4401 | return -EPERM; |
4402 | |
4403 | retval = security_task_setnice(current, nice); |
4404 | if (retval) |
4405 | return retval; |
4406 | |
4407 | set_user_nice(current, nice); |
4408 | return 0; |
4409 | } |
4410 | |
4411 | #endif |
4412 | |
4413 | /** |
4414 | * task_prio - return the priority value of a given task. |
4415 | * @p: the task in question. |
4416 | * |
4417 | * This is the priority value as seen by users in /proc. |
4418 | * RT tasks are offset by -200. Normal tasks are centered |
4419 | * around 0, value goes from -16 to +15. |
4420 | */ |
4421 | int task_prio(const struct task_struct *p) |
4422 | { |
4423 | return p->prio - MAX_RT_PRIO; |
4424 | } |
4425 | |
4426 | /** |
4427 | * task_nice - return the nice value of a given task. |
4428 | * @p: the task in question. |
4429 | */ |
4430 | int task_nice(const struct task_struct *p) |
4431 | { |
4432 | return TASK_NICE(p); |
4433 | } |
4434 | EXPORT_SYMBOL(task_nice); |
4435 | |
4436 | /** |
4437 | * idle_cpu - is a given cpu idle currently? |
4438 | * @cpu: the processor in question. |
4439 | */ |
4440 | int idle_cpu(int cpu) |
4441 | { |
4442 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; |
4443 | } |
4444 | |
4445 | /** |
4446 | * idle_task - return the idle task for a given cpu. |
4447 | * @cpu: the processor in question. |
4448 | */ |
4449 | struct task_struct *idle_task(int cpu) |
4450 | { |
4451 | return cpu_rq(cpu)->idle; |
4452 | } |
4453 | |
4454 | /** |
4455 | * find_process_by_pid - find a process with a matching PID value. |
4456 | * @pid: the pid in question. |
4457 | */ |
4458 | static struct task_struct *find_process_by_pid(pid_t pid) |
4459 | { |
4460 | return pid ? find_task_by_vpid(pid) : current; |
4461 | } |
4462 | |
4463 | /* Actually do priority change: must hold rq lock. */ |
4464 | static void |
4465 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) |
4466 | { |
4467 | BUG_ON(p->se.on_rq); |
4468 | |
4469 | p->policy = policy; |
4470 | p->rt_priority = prio; |
4471 | p->normal_prio = normal_prio(p); |
4472 | /* we are holding p->pi_lock already */ |
4473 | p->prio = rt_mutex_getprio(p); |
4474 | if (rt_prio(p->prio)) |
4475 | p->sched_class = &rt_sched_class; |
4476 | else |
4477 | p->sched_class = &fair_sched_class; |
4478 | set_load_weight(p); |
4479 | } |
4480 | |
4481 | /* |
4482 | * check the target process has a UID that matches the current process's |
4483 | */ |
4484 | static bool check_same_owner(struct task_struct *p) |
4485 | { |
4486 | const struct cred *cred = current_cred(), *pcred; |
4487 | bool match; |
4488 | |
4489 | rcu_read_lock(); |
4490 | pcred = __task_cred(p); |
4491 | match = (cred->euid == pcred->euid || |
4492 | cred->euid == pcred->uid); |
4493 | rcu_read_unlock(); |
4494 | return match; |
4495 | } |
4496 | |
4497 | static int __sched_setscheduler(struct task_struct *p, int policy, |
4498 | struct sched_param *param, bool user) |
4499 | { |
4500 | int retval, oldprio, oldpolicy = -1, on_rq, running; |
4501 | unsigned long flags; |
4502 | const struct sched_class *prev_class; |
4503 | struct rq *rq; |
4504 | int reset_on_fork; |
4505 | |
4506 | /* may grab non-irq protected spin_locks */ |
4507 | BUG_ON(in_interrupt()); |
4508 | recheck: |
4509 | /* double check policy once rq lock held */ |
4510 | if (policy < 0) { |
4511 | reset_on_fork = p->sched_reset_on_fork; |
4512 | policy = oldpolicy = p->policy; |
4513 | } else { |
4514 | reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); |
4515 | policy &= ~SCHED_RESET_ON_FORK; |
4516 | |
4517 | if (policy != SCHED_FIFO && policy != SCHED_RR && |
4518 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4519 | policy != SCHED_IDLE) |
4520 | return -EINVAL; |
4521 | } |
4522 | |
4523 | /* |
4524 | * Valid priorities for SCHED_FIFO and SCHED_RR are |
4525 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4526 | * SCHED_BATCH and SCHED_IDLE is 0. |
4527 | */ |
4528 | if (param->sched_priority < 0 || |
4529 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
4530 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
4531 | return -EINVAL; |
4532 | if (rt_policy(policy) != (param->sched_priority != 0)) |
4533 | return -EINVAL; |
4534 | |
4535 | /* |
4536 | * Allow unprivileged RT tasks to decrease priority: |
4537 | */ |
4538 | if (user && !capable(CAP_SYS_NICE)) { |
4539 | if (rt_policy(policy)) { |
4540 | unsigned long rlim_rtprio; |
4541 | |
4542 | if (!lock_task_sighand(p, &flags)) |
4543 | return -ESRCH; |
4544 | rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO); |
4545 | unlock_task_sighand(p, &flags); |
4546 | |
4547 | /* can't set/change the rt policy */ |
4548 | if (policy != p->policy && !rlim_rtprio) |
4549 | return -EPERM; |
4550 | |
4551 | /* can't increase priority */ |
4552 | if (param->sched_priority > p->rt_priority && |
4553 | param->sched_priority > rlim_rtprio) |
4554 | return -EPERM; |
4555 | } |
4556 | /* |
4557 | * Like positive nice levels, dont allow tasks to |
4558 | * move out of SCHED_IDLE either: |
4559 | */ |
4560 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) |
4561 | return -EPERM; |
4562 | |
4563 | /* can't change other user's priorities */ |
4564 | if (!check_same_owner(p)) |
4565 | return -EPERM; |
4566 | |
4567 | /* Normal users shall not reset the sched_reset_on_fork flag */ |
4568 | if (p->sched_reset_on_fork && !reset_on_fork) |
4569 | return -EPERM; |
4570 | } |
4571 | |
4572 | if (user) { |
4573 | #ifdef CONFIG_RT_GROUP_SCHED |
4574 | /* |
4575 | * Do not allow realtime tasks into groups that have no runtime |
4576 | * assigned. |
4577 | */ |
4578 | if (rt_bandwidth_enabled() && rt_policy(policy) && |
4579 | task_group(p)->rt_bandwidth.rt_runtime == 0) |
4580 | return -EPERM; |
4581 | #endif |
4582 | |
4583 | retval = security_task_setscheduler(p, policy, param); |
4584 | if (retval) |
4585 | return retval; |
4586 | } |
4587 | |
4588 | /* |
4589 | * make sure no PI-waiters arrive (or leave) while we are |
4590 | * changing the priority of the task: |
4591 | */ |
4592 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
4593 | /* |
4594 | * To be able to change p->policy safely, the apropriate |
4595 | * runqueue lock must be held. |
4596 | */ |
4597 | rq = __task_rq_lock(p); |
4598 | /* recheck policy now with rq lock held */ |
4599 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { |
4600 | policy = oldpolicy = -1; |
4601 | __task_rq_unlock(rq); |
4602 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
4603 | goto recheck; |
4604 | } |
4605 | update_rq_clock(rq); |
4606 | on_rq = p->se.on_rq; |
4607 | running = task_current(rq, p); |
4608 | if (on_rq) |
4609 | deactivate_task(rq, p, 0); |
4610 | if (running) |
4611 | p->sched_class->put_prev_task(rq, p); |
4612 | |
4613 | p->sched_reset_on_fork = reset_on_fork; |
4614 | |
4615 | oldprio = p->prio; |
4616 | prev_class = p->sched_class; |
4617 | __setscheduler(rq, p, policy, param->sched_priority); |
4618 | |
4619 | if (running) |
4620 | p->sched_class->set_curr_task(rq); |
4621 | if (on_rq) { |
4622 | activate_task(rq, p, 0); |
4623 | |
4624 | check_class_changed(rq, p, prev_class, oldprio, running); |
4625 | } |
4626 | __task_rq_unlock(rq); |
4627 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
4628 | |
4629 | rt_mutex_adjust_pi(p); |
4630 | |
4631 | return 0; |
4632 | } |
4633 | |
4634 | /** |
4635 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
4636 | * @p: the task in question. |
4637 | * @policy: new policy. |
4638 | * @param: structure containing the new RT priority. |
4639 | * |
4640 | * NOTE that the task may be already dead. |
4641 | */ |
4642 | int sched_setscheduler(struct task_struct *p, int policy, |
4643 | struct sched_param *param) |
4644 | { |
4645 | return __sched_setscheduler(p, policy, param, true); |
4646 | } |
4647 | EXPORT_SYMBOL_GPL(sched_setscheduler); |
4648 | |
4649 | /** |
4650 | * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. |
4651 | * @p: the task in question. |
4652 | * @policy: new policy. |
4653 | * @param: structure containing the new RT priority. |
4654 | * |
4655 | * Just like sched_setscheduler, only don't bother checking if the |
4656 | * current context has permission. For example, this is needed in |
4657 | * stop_machine(): we create temporary high priority worker threads, |
4658 | * but our caller might not have that capability. |
4659 | */ |
4660 | int sched_setscheduler_nocheck(struct task_struct *p, int policy, |
4661 | struct sched_param *param) |
4662 | { |
4663 | return __sched_setscheduler(p, policy, param, false); |
4664 | } |
4665 | |
4666 | static int |
4667 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) |
4668 | { |
4669 | struct sched_param lparam; |
4670 | struct task_struct *p; |
4671 | int retval; |
4672 | |
4673 | if (!param || pid < 0) |
4674 | return -EINVAL; |
4675 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) |
4676 | return -EFAULT; |
4677 | |
4678 | rcu_read_lock(); |
4679 | retval = -ESRCH; |
4680 | p = find_process_by_pid(pid); |
4681 | if (p != NULL) |
4682 | retval = sched_setscheduler(p, policy, &lparam); |
4683 | rcu_read_unlock(); |
4684 | |
4685 | return retval; |
4686 | } |
4687 | |
4688 | /** |
4689 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority |
4690 | * @pid: the pid in question. |
4691 | * @policy: new policy. |
4692 | * @param: structure containing the new RT priority. |
4693 | */ |
4694 | SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, |
4695 | struct sched_param __user *, param) |
4696 | { |
4697 | /* negative values for policy are not valid */ |
4698 | if (policy < 0) |
4699 | return -EINVAL; |
4700 | |
4701 | return do_sched_setscheduler(pid, policy, param); |
4702 | } |
4703 | |
4704 | /** |
4705 | * sys_sched_setparam - set/change the RT priority of a thread |
4706 | * @pid: the pid in question. |
4707 | * @param: structure containing the new RT priority. |
4708 | */ |
4709 | SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) |
4710 | { |
4711 | return do_sched_setscheduler(pid, -1, param); |
4712 | } |
4713 | |
4714 | /** |
4715 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread |
4716 | * @pid: the pid in question. |
4717 | */ |
4718 | SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) |
4719 | { |
4720 | struct task_struct *p; |
4721 | int retval; |
4722 | |
4723 | if (pid < 0) |
4724 | return -EINVAL; |
4725 | |
4726 | retval = -ESRCH; |
4727 | rcu_read_lock(); |
4728 | p = find_process_by_pid(pid); |
4729 | if (p) { |
4730 | retval = security_task_getscheduler(p); |
4731 | if (!retval) |
4732 | retval = p->policy |
4733 | | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); |
4734 | } |
4735 | rcu_read_unlock(); |
4736 | return retval; |
4737 | } |
4738 | |
4739 | /** |
4740 | * sys_sched_getparam - get the RT priority of a thread |
4741 | * @pid: the pid in question. |
4742 | * @param: structure containing the RT priority. |
4743 | */ |
4744 | SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) |
4745 | { |
4746 | struct sched_param lp; |
4747 | struct task_struct *p; |
4748 | int retval; |
4749 | |
4750 | if (!param || pid < 0) |
4751 | return -EINVAL; |
4752 | |
4753 | rcu_read_lock(); |
4754 | p = find_process_by_pid(pid); |
4755 | retval = -ESRCH; |
4756 | if (!p) |
4757 | goto out_unlock; |
4758 | |
4759 | retval = security_task_getscheduler(p); |
4760 | if (retval) |
4761 | goto out_unlock; |
4762 | |
4763 | lp.sched_priority = p->rt_priority; |
4764 | rcu_read_unlock(); |
4765 | |
4766 | /* |
4767 | * This one might sleep, we cannot do it with a spinlock held ... |
4768 | */ |
4769 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; |
4770 | |
4771 | return retval; |
4772 | |
4773 | out_unlock: |
4774 | rcu_read_unlock(); |
4775 | return retval; |
4776 | } |
4777 | |
4778 | long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) |
4779 | { |
4780 | cpumask_var_t cpus_allowed, new_mask; |
4781 | struct task_struct *p; |
4782 | int retval; |
4783 | |
4784 | get_online_cpus(); |
4785 | rcu_read_lock(); |
4786 | |
4787 | p = find_process_by_pid(pid); |
4788 | if (!p) { |
4789 | rcu_read_unlock(); |
4790 | put_online_cpus(); |
4791 | return -ESRCH; |
4792 | } |
4793 | |
4794 | /* Prevent p going away */ |
4795 | get_task_struct(p); |
4796 | rcu_read_unlock(); |
4797 | |
4798 | if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { |
4799 | retval = -ENOMEM; |
4800 | goto out_put_task; |
4801 | } |
4802 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { |
4803 | retval = -ENOMEM; |
4804 | goto out_free_cpus_allowed; |
4805 | } |
4806 | retval = -EPERM; |
4807 | if (!check_same_owner(p) && !capable(CAP_SYS_NICE)) |
4808 | goto out_unlock; |
4809 | |
4810 | retval = security_task_setscheduler(p, 0, NULL); |
4811 | if (retval) |
4812 | goto out_unlock; |
4813 | |
4814 | cpuset_cpus_allowed(p, cpus_allowed); |
4815 | cpumask_and(new_mask, in_mask, cpus_allowed); |
4816 | again: |
4817 | retval = set_cpus_allowed_ptr(p, new_mask); |
4818 | |
4819 | if (!retval) { |
4820 | cpuset_cpus_allowed(p, cpus_allowed); |
4821 | if (!cpumask_subset(new_mask, cpus_allowed)) { |
4822 | /* |
4823 | * We must have raced with a concurrent cpuset |
4824 | * update. Just reset the cpus_allowed to the |
4825 | * cpuset's cpus_allowed |
4826 | */ |
4827 | cpumask_copy(new_mask, cpus_allowed); |
4828 | goto again; |
4829 | } |
4830 | } |
4831 | out_unlock: |
4832 | free_cpumask_var(new_mask); |
4833 | out_free_cpus_allowed: |
4834 | free_cpumask_var(cpus_allowed); |
4835 | out_put_task: |
4836 | put_task_struct(p); |
4837 | put_online_cpus(); |
4838 | return retval; |
4839 | } |
4840 | |
4841 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, |
4842 | struct cpumask *new_mask) |
4843 | { |
4844 | if (len < cpumask_size()) |
4845 | cpumask_clear(new_mask); |
4846 | else if (len > cpumask_size()) |
4847 | len = cpumask_size(); |
4848 | |
4849 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
4850 | } |
4851 | |
4852 | /** |
4853 | * sys_sched_setaffinity - set the cpu affinity of a process |
4854 | * @pid: pid of the process |
4855 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
4856 | * @user_mask_ptr: user-space pointer to the new cpu mask |
4857 | */ |
4858 | SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, |
4859 | unsigned long __user *, user_mask_ptr) |
4860 | { |
4861 | cpumask_var_t new_mask; |
4862 | int retval; |
4863 | |
4864 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) |
4865 | return -ENOMEM; |
4866 | |
4867 | retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); |
4868 | if (retval == 0) |
4869 | retval = sched_setaffinity(pid, new_mask); |
4870 | free_cpumask_var(new_mask); |
4871 | return retval; |
4872 | } |
4873 | |
4874 | long sched_getaffinity(pid_t pid, struct cpumask *mask) |
4875 | { |
4876 | struct task_struct *p; |
4877 | unsigned long flags; |
4878 | struct rq *rq; |
4879 | int retval; |
4880 | |
4881 | get_online_cpus(); |
4882 | rcu_read_lock(); |
4883 | |
4884 | retval = -ESRCH; |
4885 | p = find_process_by_pid(pid); |
4886 | if (!p) |
4887 | goto out_unlock; |
4888 | |
4889 | retval = security_task_getscheduler(p); |
4890 | if (retval) |
4891 | goto out_unlock; |
4892 | |
4893 | rq = task_rq_lock(p, &flags); |
4894 | cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); |
4895 | task_rq_unlock(rq, &flags); |
4896 | |
4897 | out_unlock: |
4898 | rcu_read_unlock(); |
4899 | put_online_cpus(); |
4900 | |
4901 | return retval; |
4902 | } |
4903 | |
4904 | /** |
4905 | * sys_sched_getaffinity - get the cpu affinity of a process |
4906 | * @pid: pid of the process |
4907 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
4908 | * @user_mask_ptr: user-space pointer to hold the current cpu mask |
4909 | */ |
4910 | SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, |
4911 | unsigned long __user *, user_mask_ptr) |
4912 | { |
4913 | int ret; |
4914 | cpumask_var_t mask; |
4915 | |
4916 | if ((len * BITS_PER_BYTE) < nr_cpu_ids) |
4917 | return -EINVAL; |
4918 | if (len & (sizeof(unsigned long)-1)) |
4919 | return -EINVAL; |
4920 | |
4921 | if (!alloc_cpumask_var(&mask, GFP_KERNEL)) |
4922 | return -ENOMEM; |
4923 | |
4924 | ret = sched_getaffinity(pid, mask); |
4925 | if (ret == 0) { |
4926 | size_t retlen = min_t(size_t, len, cpumask_size()); |
4927 | |
4928 | if (copy_to_user(user_mask_ptr, mask, retlen)) |
4929 | ret = -EFAULT; |
4930 | else |
4931 | ret = retlen; |
4932 | } |
4933 | free_cpumask_var(mask); |
4934 | |
4935 | return ret; |
4936 | } |
4937 | |
4938 | /** |
4939 | * sys_sched_yield - yield the current processor to other threads. |
4940 | * |
4941 | * This function yields the current CPU to other tasks. If there are no |
4942 | * other threads running on this CPU then this function will return. |
4943 | */ |
4944 | SYSCALL_DEFINE0(sched_yield) |
4945 | { |
4946 | struct rq *rq = this_rq_lock(); |
4947 | |
4948 | schedstat_inc(rq, yld_count); |
4949 | current->sched_class->yield_task(rq); |
4950 | |
4951 | /* |
4952 | * Since we are going to call schedule() anyway, there's |
4953 | * no need to preempt or enable interrupts: |
4954 | */ |
4955 | __release(rq->lock); |
4956 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
4957 | do_raw_spin_unlock(&rq->lock); |
4958 | preempt_enable_no_resched(); |
4959 | |
4960 | schedule(); |
4961 | |
4962 | return 0; |
4963 | } |
4964 | |
4965 | static inline int should_resched(void) |
4966 | { |
4967 | return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); |
4968 | } |
4969 | |
4970 | static void __cond_resched(void) |
4971 | { |
4972 | add_preempt_count(PREEMPT_ACTIVE); |
4973 | schedule(); |
4974 | sub_preempt_count(PREEMPT_ACTIVE); |
4975 | } |
4976 | |
4977 | int __sched _cond_resched(void) |
4978 | { |
4979 | if (should_resched()) { |
4980 | __cond_resched(); |
4981 | return 1; |
4982 | } |
4983 | return 0; |
4984 | } |
4985 | EXPORT_SYMBOL(_cond_resched); |
4986 | |
4987 | /* |
4988 | * __cond_resched_lock() - if a reschedule is pending, drop the given lock, |
4989 | * call schedule, and on return reacquire the lock. |
4990 | * |
4991 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
4992 | * operations here to prevent schedule() from being called twice (once via |
4993 | * spin_unlock(), once by hand). |
4994 | */ |
4995 | int __cond_resched_lock(spinlock_t *lock) |
4996 | { |
4997 | int resched = should_resched(); |
4998 | int ret = 0; |
4999 | |
5000 | lockdep_assert_held(lock); |
5001 | |
5002 | if (spin_needbreak(lock) || resched) { |
5003 | spin_unlock(lock); |
5004 | if (resched) |
5005 | __cond_resched(); |
5006 | else |
5007 | cpu_relax(); |
5008 | ret = 1; |
5009 | spin_lock(lock); |
5010 | } |
5011 | return ret; |
5012 | } |
5013 | EXPORT_SYMBOL(__cond_resched_lock); |
5014 | |
5015 | int __sched __cond_resched_softirq(void) |
5016 | { |
5017 | BUG_ON(!in_softirq()); |
5018 | |
5019 | if (should_resched()) { |
5020 | local_bh_enable(); |
5021 | __cond_resched(); |
5022 | local_bh_disable(); |
5023 | return 1; |
5024 | } |
5025 | return 0; |
5026 | } |
5027 | EXPORT_SYMBOL(__cond_resched_softirq); |
5028 | |
5029 | /** |
5030 | * yield - yield the current processor to other threads. |
5031 | * |
5032 | * This is a shortcut for kernel-space yielding - it marks the |
5033 | * thread runnable and calls sys_sched_yield(). |
5034 | */ |
5035 | void __sched yield(void) |
5036 | { |
5037 | set_current_state(TASK_RUNNING); |
5038 | sys_sched_yield(); |
5039 | } |
5040 | EXPORT_SYMBOL(yield); |
5041 | |
5042 | /* |
5043 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
5044 | * that process accounting knows that this is a task in IO wait state. |
5045 | */ |
5046 | void __sched io_schedule(void) |
5047 | { |
5048 | struct rq *rq = raw_rq(); |
5049 | |
5050 | delayacct_blkio_start(); |
5051 | atomic_inc(&rq->nr_iowait); |
5052 | current->in_iowait = 1; |
5053 | schedule(); |
5054 | current->in_iowait = 0; |
5055 | atomic_dec(&rq->nr_iowait); |
5056 | delayacct_blkio_end(); |
5057 | } |
5058 | EXPORT_SYMBOL(io_schedule); |
5059 | |
5060 | long __sched io_schedule_timeout(long timeout) |
5061 | { |
5062 | struct rq *rq = raw_rq(); |
5063 | long ret; |
5064 | |
5065 | delayacct_blkio_start(); |
5066 | atomic_inc(&rq->nr_iowait); |
5067 | current->in_iowait = 1; |
5068 | ret = schedule_timeout(timeout); |
5069 | current->in_iowait = 0; |
5070 | atomic_dec(&rq->nr_iowait); |
5071 | delayacct_blkio_end(); |
5072 | return ret; |
5073 | } |
5074 | |
5075 | /** |
5076 | * sys_sched_get_priority_max - return maximum RT priority. |
5077 | * @policy: scheduling class. |
5078 | * |
5079 | * this syscall returns the maximum rt_priority that can be used |
5080 | * by a given scheduling class. |
5081 | */ |
5082 | SYSCALL_DEFINE1(sched_get_priority_max, int, policy) |
5083 | { |
5084 | int ret = -EINVAL; |
5085 | |
5086 | switch (policy) { |
5087 | case SCHED_FIFO: |
5088 | case SCHED_RR: |
5089 | ret = MAX_USER_RT_PRIO-1; |
5090 | break; |
5091 | case SCHED_NORMAL: |
5092 | case SCHED_BATCH: |
5093 | case SCHED_IDLE: |
5094 | ret = 0; |
5095 | break; |
5096 | } |
5097 | return ret; |
5098 | } |
5099 | |
5100 | /** |
5101 | * sys_sched_get_priority_min - return minimum RT priority. |
5102 | * @policy: scheduling class. |
5103 | * |
5104 | * this syscall returns the minimum rt_priority that can be used |
5105 | * by a given scheduling class. |
5106 | */ |
5107 | SYSCALL_DEFINE1(sched_get_priority_min, int, policy) |
5108 | { |
5109 | int ret = -EINVAL; |
5110 | |
5111 | switch (policy) { |
5112 | case SCHED_FIFO: |
5113 | case SCHED_RR: |
5114 | ret = 1; |
5115 | break; |
5116 | case SCHED_NORMAL: |
5117 | case SCHED_BATCH: |
5118 | case SCHED_IDLE: |
5119 | ret = 0; |
5120 | } |
5121 | return ret; |
5122 | } |
5123 | |
5124 | /** |
5125 | * sys_sched_rr_get_interval - return the default timeslice of a process. |
5126 | * @pid: pid of the process. |
5127 | * @interval: userspace pointer to the timeslice value. |
5128 | * |
5129 | * this syscall writes the default timeslice value of a given process |
5130 | * into the user-space timespec buffer. A value of '0' means infinity. |
5131 | */ |
5132 | SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, |
5133 | struct timespec __user *, interval) |
5134 | { |
5135 | struct task_struct *p; |
5136 | unsigned int time_slice; |
5137 | unsigned long flags; |
5138 | struct rq *rq; |
5139 | int retval; |
5140 | struct timespec t; |
5141 | |
5142 | if (pid < 0) |
5143 | return -EINVAL; |
5144 | |
5145 | retval = -ESRCH; |
5146 | rcu_read_lock(); |
5147 | p = find_process_by_pid(pid); |
5148 | if (!p) |
5149 | goto out_unlock; |
5150 | |
5151 | retval = security_task_getscheduler(p); |
5152 | if (retval) |
5153 | goto out_unlock; |
5154 | |
5155 | rq = task_rq_lock(p, &flags); |
5156 | time_slice = p->sched_class->get_rr_interval(rq, p); |
5157 | task_rq_unlock(rq, &flags); |
5158 | |
5159 | rcu_read_unlock(); |
5160 | jiffies_to_timespec(time_slice, &t); |
5161 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
5162 | return retval; |
5163 | |
5164 | out_unlock: |
5165 | rcu_read_unlock(); |
5166 | return retval; |
5167 | } |
5168 | |
5169 | static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; |
5170 | |
5171 | void sched_show_task(struct task_struct *p) |
5172 | { |
5173 | unsigned long free = 0; |
5174 | unsigned state; |
5175 | |
5176 | state = p->state ? __ffs(p->state) + 1 : 0; |
5177 | printk(KERN_INFO "%-13.13s %c", p->comm, |
5178 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
5179 | #if BITS_PER_LONG == 32 |
5180 | if (state == TASK_RUNNING) |
5181 | printk(KERN_CONT " running "); |
5182 | else |
5183 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
5184 | #else |
5185 | if (state == TASK_RUNNING) |
5186 | printk(KERN_CONT " running task "); |
5187 | else |
5188 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
5189 | #endif |
5190 | #ifdef CONFIG_DEBUG_STACK_USAGE |
5191 | free = stack_not_used(p); |
5192 | #endif |
5193 | printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, |
5194 | task_pid_nr(p), task_pid_nr(p->real_parent), |
5195 | (unsigned long)task_thread_info(p)->flags); |
5196 | |
5197 | show_stack(p, NULL); |
5198 | } |
5199 | |
5200 | void show_state_filter(unsigned long state_filter) |
5201 | { |
5202 | struct task_struct *g, *p; |
5203 | |
5204 | #if BITS_PER_LONG == 32 |
5205 | printk(KERN_INFO |
5206 | " task PC stack pid father\n"); |
5207 | #else |
5208 | printk(KERN_INFO |
5209 | " task PC stack pid father\n"); |
5210 | #endif |
5211 | read_lock(&tasklist_lock); |
5212 | do_each_thread(g, p) { |
5213 | /* |
5214 | * reset the NMI-timeout, listing all files on a slow |
5215 | * console might take alot of time: |
5216 | */ |
5217 | touch_nmi_watchdog(); |
5218 | if (!state_filter || (p->state & state_filter)) |
5219 | sched_show_task(p); |
5220 | } while_each_thread(g, p); |
5221 | |
5222 | touch_all_softlockup_watchdogs(); |
5223 | |
5224 | #ifdef CONFIG_SCHED_DEBUG |
5225 | sysrq_sched_debug_show(); |
5226 | #endif |
5227 | read_unlock(&tasklist_lock); |
5228 | /* |
5229 | * Only show locks if all tasks are dumped: |
5230 | */ |
5231 | if (!state_filter) |
5232 | debug_show_all_locks(); |
5233 | } |
5234 | |
5235 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
5236 | { |
5237 | idle->sched_class = &idle_sched_class; |
5238 | } |
5239 | |
5240 | /** |
5241 | * init_idle - set up an idle thread for a given CPU |
5242 | * @idle: task in question |
5243 | * @cpu: cpu the idle task belongs to |
5244 | * |
5245 | * NOTE: this function does not set the idle thread's NEED_RESCHED |
5246 | * flag, to make booting more robust. |
5247 | */ |
5248 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
5249 | { |
5250 | struct rq *rq = cpu_rq(cpu); |
5251 | unsigned long flags; |
5252 | |
5253 | raw_spin_lock_irqsave(&rq->lock, flags); |
5254 | |
5255 | __sched_fork(idle); |
5256 | idle->state = TASK_RUNNING; |
5257 | idle->se.exec_start = sched_clock(); |
5258 | |
5259 | cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu)); |
5260 | __set_task_cpu(idle, cpu); |
5261 | |
5262 | rq->curr = rq->idle = idle; |
5263 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
5264 | idle->oncpu = 1; |
5265 | #endif |
5266 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5267 | |
5268 | /* Set the preempt count _outside_ the spinlocks! */ |
5269 | #if defined(CONFIG_PREEMPT) |
5270 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
5271 | #else |
5272 | task_thread_info(idle)->preempt_count = 0; |
5273 | #endif |
5274 | /* |
5275 | * The idle tasks have their own, simple scheduling class: |
5276 | */ |
5277 | idle->sched_class = &idle_sched_class; |
5278 | ftrace_graph_init_task(idle); |
5279 | } |
5280 | |
5281 | /* |
5282 | * In a system that switches off the HZ timer nohz_cpu_mask |
5283 | * indicates which cpus entered this state. This is used |
5284 | * in the rcu update to wait only for active cpus. For system |
5285 | * which do not switch off the HZ timer nohz_cpu_mask should |
5286 | * always be CPU_BITS_NONE. |
5287 | */ |
5288 | cpumask_var_t nohz_cpu_mask; |
5289 | |
5290 | /* |
5291 | * Increase the granularity value when there are more CPUs, |
5292 | * because with more CPUs the 'effective latency' as visible |
5293 | * to users decreases. But the relationship is not linear, |
5294 | * so pick a second-best guess by going with the log2 of the |
5295 | * number of CPUs. |
5296 | * |
5297 | * This idea comes from the SD scheduler of Con Kolivas: |
5298 | */ |
5299 | static int get_update_sysctl_factor(void) |
5300 | { |
5301 | unsigned int cpus = min_t(int, num_online_cpus(), 8); |
5302 | unsigned int factor; |
5303 | |
5304 | switch (sysctl_sched_tunable_scaling) { |
5305 | case SCHED_TUNABLESCALING_NONE: |
5306 | factor = 1; |
5307 | break; |
5308 | case SCHED_TUNABLESCALING_LINEAR: |
5309 | factor = cpus; |
5310 | break; |
5311 | case SCHED_TUNABLESCALING_LOG: |
5312 | default: |
5313 | factor = 1 + ilog2(cpus); |
5314 | break; |
5315 | } |
5316 | |
5317 | return factor; |
5318 | } |
5319 | |
5320 | static void update_sysctl(void) |
5321 | { |
5322 | unsigned int factor = get_update_sysctl_factor(); |
5323 | |
5324 | #define SET_SYSCTL(name) \ |
5325 | (sysctl_##name = (factor) * normalized_sysctl_##name) |
5326 | SET_SYSCTL(sched_min_granularity); |
5327 | SET_SYSCTL(sched_latency); |
5328 | SET_SYSCTL(sched_wakeup_granularity); |
5329 | SET_SYSCTL(sched_shares_ratelimit); |
5330 | #undef SET_SYSCTL |
5331 | } |
5332 | |
5333 | static inline void sched_init_granularity(void) |
5334 | { |
5335 | update_sysctl(); |
5336 | } |
5337 | |
5338 | #ifdef CONFIG_SMP |
5339 | /* |
5340 | * This is how migration works: |
5341 | * |
5342 | * 1) we queue a struct migration_req structure in the source CPU's |
5343 | * runqueue and wake up that CPU's migration thread. |
5344 | * 2) we down() the locked semaphore => thread blocks. |
5345 | * 3) migration thread wakes up (implicitly it forces the migrated |
5346 | * thread off the CPU) |
5347 | * 4) it gets the migration request and checks whether the migrated |
5348 | * task is still in the wrong runqueue. |
5349 | * 5) if it's in the wrong runqueue then the migration thread removes |
5350 | * it and puts it into the right queue. |
5351 | * 6) migration thread up()s the semaphore. |
5352 | * 7) we wake up and the migration is done. |
5353 | */ |
5354 | |
5355 | /* |
5356 | * Change a given task's CPU affinity. Migrate the thread to a |
5357 | * proper CPU and schedule it away if the CPU it's executing on |
5358 | * is removed from the allowed bitmask. |
5359 | * |
5360 | * NOTE: the caller must have a valid reference to the task, the |
5361 | * task must not exit() & deallocate itself prematurely. The |
5362 | * call is not atomic; no spinlocks may be held. |
5363 | */ |
5364 | int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) |
5365 | { |
5366 | struct migration_req req; |
5367 | unsigned long flags; |
5368 | struct rq *rq; |
5369 | int ret = 0; |
5370 | |
5371 | rq = task_rq_lock(p, &flags); |
5372 | |
5373 | if (!cpumask_intersects(new_mask, cpu_active_mask)) { |
5374 | ret = -EINVAL; |
5375 | goto out; |
5376 | } |
5377 | |
5378 | if (unlikely((p->flags & PF_THREAD_BOUND) && p != current && |
5379 | !cpumask_equal(&p->cpus_allowed, new_mask))) { |
5380 | ret = -EINVAL; |
5381 | goto out; |
5382 | } |
5383 | |
5384 | if (p->sched_class->set_cpus_allowed) |
5385 | p->sched_class->set_cpus_allowed(p, new_mask); |
5386 | else { |
5387 | cpumask_copy(&p->cpus_allowed, new_mask); |
5388 | p->rt.nr_cpus_allowed = cpumask_weight(new_mask); |
5389 | } |
5390 | |
5391 | /* Can the task run on the task's current CPU? If so, we're done */ |
5392 | if (cpumask_test_cpu(task_cpu(p), new_mask)) |
5393 | goto out; |
5394 | |
5395 | if (migrate_task(p, cpumask_any_and(cpu_active_mask, new_mask), &req)) { |
5396 | /* Need help from migration thread: drop lock and wait. */ |
5397 | struct task_struct *mt = rq->migration_thread; |
5398 | |
5399 | get_task_struct(mt); |
5400 | task_rq_unlock(rq, &flags); |
5401 | wake_up_process(mt); |
5402 | put_task_struct(mt); |
5403 | wait_for_completion(&req.done); |
5404 | tlb_migrate_finish(p->mm); |
5405 | return 0; |
5406 | } |
5407 | out: |
5408 | task_rq_unlock(rq, &flags); |
5409 | |
5410 | return ret; |
5411 | } |
5412 | EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); |
5413 | |
5414 | /* |
5415 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
5416 | * this because either it can't run here any more (set_cpus_allowed() |
5417 | * away from this CPU, or CPU going down), or because we're |
5418 | * attempting to rebalance this task on exec (sched_exec). |
5419 | * |
5420 | * So we race with normal scheduler movements, but that's OK, as long |
5421 | * as the task is no longer on this CPU. |
5422 | * |
5423 | * Returns non-zero if task was successfully migrated. |
5424 | */ |
5425 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
5426 | { |
5427 | struct rq *rq_dest, *rq_src; |
5428 | int ret = 0; |
5429 | |
5430 | if (unlikely(!cpu_active(dest_cpu))) |
5431 | return ret; |
5432 | |
5433 | rq_src = cpu_rq(src_cpu); |
5434 | rq_dest = cpu_rq(dest_cpu); |
5435 | |
5436 | double_rq_lock(rq_src, rq_dest); |
5437 | /* Already moved. */ |
5438 | if (task_cpu(p) != src_cpu) |
5439 | goto done; |
5440 | /* Affinity changed (again). */ |
5441 | if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)) |
5442 | goto fail; |
5443 | |
5444 | /* |
5445 | * If we're not on a rq, the next wake-up will ensure we're |
5446 | * placed properly. |
5447 | */ |
5448 | if (p->se.on_rq) { |
5449 | deactivate_task(rq_src, p, 0); |
5450 | set_task_cpu(p, dest_cpu); |
5451 | activate_task(rq_dest, p, 0); |
5452 | check_preempt_curr(rq_dest, p, 0); |
5453 | } |
5454 | done: |
5455 | ret = 1; |
5456 | fail: |
5457 | double_rq_unlock(rq_src, rq_dest); |
5458 | return ret; |
5459 | } |
5460 | |
5461 | #define RCU_MIGRATION_IDLE 0 |
5462 | #define RCU_MIGRATION_NEED_QS 1 |
5463 | #define RCU_MIGRATION_GOT_QS 2 |
5464 | #define RCU_MIGRATION_MUST_SYNC 3 |
5465 | |
5466 | /* |
5467 | * migration_thread - this is a highprio system thread that performs |
5468 | * thread migration by bumping thread off CPU then 'pushing' onto |
5469 | * another runqueue. |
5470 | */ |
5471 | static int migration_thread(void *data) |
5472 | { |
5473 | int badcpu; |
5474 | int cpu = (long)data; |
5475 | struct rq *rq; |
5476 | |
5477 | rq = cpu_rq(cpu); |
5478 | BUG_ON(rq->migration_thread != current); |
5479 | |
5480 | set_current_state(TASK_INTERRUPTIBLE); |
5481 | while (!kthread_should_stop()) { |
5482 | struct migration_req *req; |
5483 | struct list_head *head; |
5484 | |
5485 | raw_spin_lock_irq(&rq->lock); |
5486 | |
5487 | if (cpu_is_offline(cpu)) { |
5488 | raw_spin_unlock_irq(&rq->lock); |
5489 | break; |
5490 | } |
5491 | |
5492 | if (rq->active_balance) { |
5493 | active_load_balance(rq, cpu); |
5494 | rq->active_balance = 0; |
5495 | } |
5496 | |
5497 | head = &rq->migration_queue; |
5498 | |
5499 | if (list_empty(head)) { |
5500 | raw_spin_unlock_irq(&rq->lock); |
5501 | schedule(); |
5502 | set_current_state(TASK_INTERRUPTIBLE); |
5503 | continue; |
5504 | } |
5505 | req = list_entry(head->next, struct migration_req, list); |
5506 | list_del_init(head->next); |
5507 | |
5508 | if (req->task != NULL) { |
5509 | raw_spin_unlock(&rq->lock); |
5510 | __migrate_task(req->task, cpu, req->dest_cpu); |
5511 | } else if (likely(cpu == (badcpu = smp_processor_id()))) { |
5512 | req->dest_cpu = RCU_MIGRATION_GOT_QS; |
5513 | raw_spin_unlock(&rq->lock); |
5514 | } else { |
5515 | req->dest_cpu = RCU_MIGRATION_MUST_SYNC; |
5516 | raw_spin_unlock(&rq->lock); |
5517 | WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu, cpu); |
5518 | } |
5519 | local_irq_enable(); |
5520 | |
5521 | complete(&req->done); |
5522 | } |
5523 | __set_current_state(TASK_RUNNING); |
5524 | |
5525 | return 0; |
5526 | } |
5527 | |
5528 | #ifdef CONFIG_HOTPLUG_CPU |
5529 | |
5530 | static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) |
5531 | { |
5532 | int ret; |
5533 | |
5534 | local_irq_disable(); |
5535 | ret = __migrate_task(p, src_cpu, dest_cpu); |
5536 | local_irq_enable(); |
5537 | return ret; |
5538 | } |
5539 | |
5540 | /* |
5541 | * Figure out where task on dead CPU should go, use force if necessary. |
5542 | */ |
5543 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
5544 | { |
5545 | int dest_cpu; |
5546 | |
5547 | again: |
5548 | dest_cpu = select_fallback_rq(dead_cpu, p); |
5549 | |
5550 | /* It can have affinity changed while we were choosing. */ |
5551 | if (unlikely(!__migrate_task_irq(p, dead_cpu, dest_cpu))) |
5552 | goto again; |
5553 | } |
5554 | |
5555 | /* |
5556 | * While a dead CPU has no uninterruptible tasks queued at this point, |
5557 | * it might still have a nonzero ->nr_uninterruptible counter, because |
5558 | * for performance reasons the counter is not stricly tracking tasks to |
5559 | * their home CPUs. So we just add the counter to another CPU's counter, |
5560 | * to keep the global sum constant after CPU-down: |
5561 | */ |
5562 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
5563 | { |
5564 | struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask)); |
5565 | unsigned long flags; |
5566 | |
5567 | local_irq_save(flags); |
5568 | double_rq_lock(rq_src, rq_dest); |
5569 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; |
5570 | rq_src->nr_uninterruptible = 0; |
5571 | double_rq_unlock(rq_src, rq_dest); |
5572 | local_irq_restore(flags); |
5573 | } |
5574 | |
5575 | /* Run through task list and migrate tasks from the dead cpu. */ |
5576 | static void migrate_live_tasks(int src_cpu) |
5577 | { |
5578 | struct task_struct *p, *t; |
5579 | |
5580 | read_lock(&tasklist_lock); |
5581 | |
5582 | do_each_thread(t, p) { |
5583 | if (p == current) |
5584 | continue; |
5585 | |
5586 | if (task_cpu(p) == src_cpu) |
5587 | move_task_off_dead_cpu(src_cpu, p); |
5588 | } while_each_thread(t, p); |
5589 | |
5590 | read_unlock(&tasklist_lock); |
5591 | } |
5592 | |
5593 | /* |
5594 | * Schedules idle task to be the next runnable task on current CPU. |
5595 | * It does so by boosting its priority to highest possible. |
5596 | * Used by CPU offline code. |
5597 | */ |
5598 | void sched_idle_next(void) |
5599 | { |
5600 | int this_cpu = smp_processor_id(); |
5601 | struct rq *rq = cpu_rq(this_cpu); |
5602 | struct task_struct *p = rq->idle; |
5603 | unsigned long flags; |
5604 | |
5605 | /* cpu has to be offline */ |
5606 | BUG_ON(cpu_online(this_cpu)); |
5607 | |
5608 | /* |
5609 | * Strictly not necessary since rest of the CPUs are stopped by now |
5610 | * and interrupts disabled on the current cpu. |
5611 | */ |
5612 | raw_spin_lock_irqsave(&rq->lock, flags); |
5613 | |
5614 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
5615 | |
5616 | update_rq_clock(rq); |
5617 | activate_task(rq, p, 0); |
5618 | |
5619 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5620 | } |
5621 | |
5622 | /* |
5623 | * Ensures that the idle task is using init_mm right before its cpu goes |
5624 | * offline. |
5625 | */ |
5626 | void idle_task_exit(void) |
5627 | { |
5628 | struct mm_struct *mm = current->active_mm; |
5629 | |
5630 | BUG_ON(cpu_online(smp_processor_id())); |
5631 | |
5632 | if (mm != &init_mm) |
5633 | switch_mm(mm, &init_mm, current); |
5634 | mmdrop(mm); |
5635 | } |
5636 | |
5637 | /* called under rq->lock with disabled interrupts */ |
5638 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
5639 | { |
5640 | struct rq *rq = cpu_rq(dead_cpu); |
5641 | |
5642 | /* Must be exiting, otherwise would be on tasklist. */ |
5643 | BUG_ON(!p->exit_state); |
5644 | |
5645 | /* Cannot have done final schedule yet: would have vanished. */ |
5646 | BUG_ON(p->state == TASK_DEAD); |
5647 | |
5648 | get_task_struct(p); |
5649 | |
5650 | /* |
5651 | * Drop lock around migration; if someone else moves it, |
5652 | * that's OK. No task can be added to this CPU, so iteration is |
5653 | * fine. |
5654 | */ |
5655 | raw_spin_unlock_irq(&rq->lock); |
5656 | move_task_off_dead_cpu(dead_cpu, p); |
5657 | raw_spin_lock_irq(&rq->lock); |
5658 | |
5659 | put_task_struct(p); |
5660 | } |
5661 | |
5662 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ |
5663 | static void migrate_dead_tasks(unsigned int dead_cpu) |
5664 | { |
5665 | struct rq *rq = cpu_rq(dead_cpu); |
5666 | struct task_struct *next; |
5667 | |
5668 | for ( ; ; ) { |
5669 | if (!rq->nr_running) |
5670 | break; |
5671 | update_rq_clock(rq); |
5672 | next = pick_next_task(rq); |
5673 | if (!next) |
5674 | break; |
5675 | next->sched_class->put_prev_task(rq, next); |
5676 | migrate_dead(dead_cpu, next); |
5677 | |
5678 | } |
5679 | } |
5680 | |
5681 | /* |
5682 | * remove the tasks which were accounted by rq from calc_load_tasks. |
5683 | */ |
5684 | static void calc_global_load_remove(struct rq *rq) |
5685 | { |
5686 | atomic_long_sub(rq->calc_load_active, &calc_load_tasks); |
5687 | rq->calc_load_active = 0; |
5688 | } |
5689 | #endif /* CONFIG_HOTPLUG_CPU */ |
5690 | |
5691 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
5692 | |
5693 | static struct ctl_table sd_ctl_dir[] = { |
5694 | { |
5695 | .procname = "sched_domain", |
5696 | .mode = 0555, |
5697 | }, |
5698 | {} |
5699 | }; |
5700 | |
5701 | static struct ctl_table sd_ctl_root[] = { |
5702 | { |
5703 | .procname = "kernel", |
5704 | .mode = 0555, |
5705 | .child = sd_ctl_dir, |
5706 | }, |
5707 | {} |
5708 | }; |
5709 | |
5710 | static struct ctl_table *sd_alloc_ctl_entry(int n) |
5711 | { |
5712 | struct ctl_table *entry = |
5713 | kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
5714 | |
5715 | return entry; |
5716 | } |
5717 | |
5718 | static void sd_free_ctl_entry(struct ctl_table **tablep) |
5719 | { |
5720 | struct ctl_table *entry; |
5721 | |
5722 | /* |
5723 | * In the intermediate directories, both the child directory and |
5724 | * procname are dynamically allocated and could fail but the mode |
5725 | * will always be set. In the lowest directory the names are |
5726 | * static strings and all have proc handlers. |
5727 | */ |
5728 | for (entry = *tablep; entry->mode; entry++) { |
5729 | if (entry->child) |
5730 | sd_free_ctl_entry(&entry->child); |
5731 | if (entry->proc_handler == NULL) |
5732 | kfree(entry->procname); |
5733 | } |
5734 | |
5735 | kfree(*tablep); |
5736 | *tablep = NULL; |
5737 | } |
5738 | |
5739 | static void |
5740 | set_table_entry(struct ctl_table *entry, |
5741 | const char *procname, void *data, int maxlen, |
5742 | mode_t mode, proc_handler *proc_handler) |
5743 | { |
5744 | entry->procname = procname; |
5745 | entry->data = data; |
5746 | entry->maxlen = maxlen; |
5747 | entry->mode = mode; |
5748 | entry->proc_handler = proc_handler; |
5749 | } |
5750 | |
5751 | static struct ctl_table * |
5752 | sd_alloc_ctl_domain_table(struct sched_domain *sd) |
5753 | { |
5754 | struct ctl_table *table = sd_alloc_ctl_entry(13); |
5755 | |
5756 | if (table == NULL) |
5757 | return NULL; |
5758 | |
5759 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
5760 | sizeof(long), 0644, proc_doulongvec_minmax); |
5761 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
5762 | sizeof(long), 0644, proc_doulongvec_minmax); |
5763 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
5764 | sizeof(int), 0644, proc_dointvec_minmax); |
5765 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
5766 | sizeof(int), 0644, proc_dointvec_minmax); |
5767 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
5768 | sizeof(int), 0644, proc_dointvec_minmax); |
5769 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
5770 | sizeof(int), 0644, proc_dointvec_minmax); |
5771 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
5772 | sizeof(int), 0644, proc_dointvec_minmax); |
5773 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
5774 | sizeof(int), 0644, proc_dointvec_minmax); |
5775 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
5776 | sizeof(int), 0644, proc_dointvec_minmax); |
5777 | set_table_entry(&table[9], "cache_nice_tries", |
5778 | &sd->cache_nice_tries, |
5779 | sizeof(int), 0644, proc_dointvec_minmax); |
5780 | set_table_entry(&table[10], "flags", &sd->flags, |
5781 | sizeof(int), 0644, proc_dointvec_minmax); |
5782 | set_table_entry(&table[11], "name", sd->name, |
5783 | CORENAME_MAX_SIZE, 0444, proc_dostring); |
5784 | /* &table[12] is terminator */ |
5785 | |
5786 | return table; |
5787 | } |
5788 | |
5789 | static ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
5790 | { |
5791 | struct ctl_table *entry, *table; |
5792 | struct sched_domain *sd; |
5793 | int domain_num = 0, i; |
5794 | char buf[32]; |
5795 | |
5796 | for_each_domain(cpu, sd) |
5797 | domain_num++; |
5798 | entry = table = sd_alloc_ctl_entry(domain_num + 1); |
5799 | if (table == NULL) |
5800 | return NULL; |
5801 | |
5802 | i = 0; |
5803 | for_each_domain(cpu, sd) { |
5804 | snprintf(buf, 32, "domain%d", i); |
5805 | entry->procname = kstrdup(buf, GFP_KERNEL); |
5806 | entry->mode = 0555; |
5807 | entry->child = sd_alloc_ctl_domain_table(sd); |
5808 | entry++; |
5809 | i++; |
5810 | } |
5811 | return table; |
5812 | } |
5813 | |
5814 | static struct ctl_table_header *sd_sysctl_header; |
5815 | static void register_sched_domain_sysctl(void) |
5816 | { |
5817 | int i, cpu_num = num_possible_cpus(); |
5818 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); |
5819 | char buf[32]; |
5820 | |
5821 | WARN_ON(sd_ctl_dir[0].child); |
5822 | sd_ctl_dir[0].child = entry; |
5823 | |
5824 | if (entry == NULL) |
5825 | return; |
5826 | |
5827 | for_each_possible_cpu(i) { |
5828 | snprintf(buf, 32, "cpu%d", i); |
5829 | entry->procname = kstrdup(buf, GFP_KERNEL); |
5830 | entry->mode = 0555; |
5831 | entry->child = sd_alloc_ctl_cpu_table(i); |
5832 | entry++; |
5833 | } |
5834 | |
5835 | WARN_ON(sd_sysctl_header); |
5836 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
5837 | } |
5838 | |
5839 | /* may be called multiple times per register */ |
5840 | static void unregister_sched_domain_sysctl(void) |
5841 | { |
5842 | if (sd_sysctl_header) |
5843 | unregister_sysctl_table(sd_sysctl_header); |
5844 | sd_sysctl_header = NULL; |
5845 | if (sd_ctl_dir[0].child) |
5846 | sd_free_ctl_entry(&sd_ctl_dir[0].child); |
5847 | } |
5848 | #else |
5849 | static void register_sched_domain_sysctl(void) |
5850 | { |
5851 | } |
5852 | static void unregister_sched_domain_sysctl(void) |
5853 | { |
5854 | } |
5855 | #endif |
5856 | |
5857 | static void set_rq_online(struct rq *rq) |
5858 | { |
5859 | if (!rq->online) { |
5860 | const struct sched_class *class; |
5861 | |
5862 | cpumask_set_cpu(rq->cpu, rq->rd->online); |
5863 | rq->online = 1; |
5864 | |
5865 | for_each_class(class) { |
5866 | if (class->rq_online) |
5867 | class->rq_online(rq); |
5868 | } |
5869 | } |
5870 | } |
5871 | |
5872 | static void set_rq_offline(struct rq *rq) |
5873 | { |
5874 | if (rq->online) { |
5875 | const struct sched_class *class; |
5876 | |
5877 | for_each_class(class) { |
5878 | if (class->rq_offline) |
5879 | class->rq_offline(rq); |
5880 | } |
5881 | |
5882 | cpumask_clear_cpu(rq->cpu, rq->rd->online); |
5883 | rq->online = 0; |
5884 | } |
5885 | } |
5886 | |
5887 | /* |
5888 | * migration_call - callback that gets triggered when a CPU is added. |
5889 | * Here we can start up the necessary migration thread for the new CPU. |
5890 | */ |
5891 | static int __cpuinit |
5892 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) |
5893 | { |
5894 | struct task_struct *p; |
5895 | int cpu = (long)hcpu; |
5896 | unsigned long flags; |
5897 | struct rq *rq; |
5898 | |
5899 | switch (action) { |
5900 | |
5901 | case CPU_UP_PREPARE: |
5902 | case CPU_UP_PREPARE_FROZEN: |
5903 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
5904 | if (IS_ERR(p)) |
5905 | return NOTIFY_BAD; |
5906 | kthread_bind(p, cpu); |
5907 | /* Must be high prio: stop_machine expects to yield to it. */ |
5908 | rq = task_rq_lock(p, &flags); |
5909 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
5910 | task_rq_unlock(rq, &flags); |
5911 | get_task_struct(p); |
5912 | cpu_rq(cpu)->migration_thread = p; |
5913 | rq->calc_load_update = calc_load_update; |
5914 | break; |
5915 | |
5916 | case CPU_ONLINE: |
5917 | case CPU_ONLINE_FROZEN: |
5918 | /* Strictly unnecessary, as first user will wake it. */ |
5919 | wake_up_process(cpu_rq(cpu)->migration_thread); |
5920 | |
5921 | /* Update our root-domain */ |
5922 | rq = cpu_rq(cpu); |
5923 | raw_spin_lock_irqsave(&rq->lock, flags); |
5924 | if (rq->rd) { |
5925 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
5926 | |
5927 | set_rq_online(rq); |
5928 | } |
5929 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5930 | break; |
5931 | |
5932 | #ifdef CONFIG_HOTPLUG_CPU |
5933 | case CPU_UP_CANCELED: |
5934 | case CPU_UP_CANCELED_FROZEN: |
5935 | if (!cpu_rq(cpu)->migration_thread) |
5936 | break; |
5937 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
5938 | kthread_bind(cpu_rq(cpu)->migration_thread, |
5939 | cpumask_any(cpu_online_mask)); |
5940 | kthread_stop(cpu_rq(cpu)->migration_thread); |
5941 | put_task_struct(cpu_rq(cpu)->migration_thread); |
5942 | cpu_rq(cpu)->migration_thread = NULL; |
5943 | break; |
5944 | |
5945 | case CPU_DEAD: |
5946 | case CPU_DEAD_FROZEN: |
5947 | cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */ |
5948 | migrate_live_tasks(cpu); |
5949 | rq = cpu_rq(cpu); |
5950 | kthread_stop(rq->migration_thread); |
5951 | put_task_struct(rq->migration_thread); |
5952 | rq->migration_thread = NULL; |
5953 | /* Idle task back to normal (off runqueue, low prio) */ |
5954 | raw_spin_lock_irq(&rq->lock); |
5955 | update_rq_clock(rq); |
5956 | deactivate_task(rq, rq->idle, 0); |
5957 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
5958 | rq->idle->sched_class = &idle_sched_class; |
5959 | migrate_dead_tasks(cpu); |
5960 | raw_spin_unlock_irq(&rq->lock); |
5961 | cpuset_unlock(); |
5962 | migrate_nr_uninterruptible(rq); |
5963 | BUG_ON(rq->nr_running != 0); |
5964 | calc_global_load_remove(rq); |
5965 | /* |
5966 | * No need to migrate the tasks: it was best-effort if |
5967 | * they didn't take sched_hotcpu_mutex. Just wake up |
5968 | * the requestors. |
5969 | */ |
5970 | raw_spin_lock_irq(&rq->lock); |
5971 | while (!list_empty(&rq->migration_queue)) { |
5972 | struct migration_req *req; |
5973 | |
5974 | req = list_entry(rq->migration_queue.next, |
5975 | struct migration_req, list); |
5976 | list_del_init(&req->list); |
5977 | raw_spin_unlock_irq(&rq->lock); |
5978 | complete(&req->done); |
5979 | raw_spin_lock_irq(&rq->lock); |
5980 | } |
5981 | raw_spin_unlock_irq(&rq->lock); |
5982 | break; |
5983 | |
5984 | case CPU_DYING: |
5985 | case CPU_DYING_FROZEN: |
5986 | /* Update our root-domain */ |
5987 | rq = cpu_rq(cpu); |
5988 | raw_spin_lock_irqsave(&rq->lock, flags); |
5989 | if (rq->rd) { |
5990 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
5991 | set_rq_offline(rq); |
5992 | } |
5993 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5994 | break; |
5995 | #endif |
5996 | } |
5997 | return NOTIFY_OK; |
5998 | } |
5999 | |
6000 | /* |
6001 | * Register at high priority so that task migration (migrate_all_tasks) |
6002 | * happens before everything else. This has to be lower priority than |
6003 | * the notifier in the perf_event subsystem, though. |
6004 | */ |
6005 | static struct notifier_block __cpuinitdata migration_notifier = { |
6006 | .notifier_call = migration_call, |
6007 | .priority = 10 |
6008 | }; |
6009 | |
6010 | static int __init migration_init(void) |
6011 | { |
6012 | void *cpu = (void *)(long)smp_processor_id(); |
6013 | int err; |
6014 | |
6015 | /* Start one for the boot CPU: */ |
6016 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
6017 | BUG_ON(err == NOTIFY_BAD); |
6018 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
6019 | register_cpu_notifier(&migration_notifier); |
6020 | |
6021 | return 0; |
6022 | } |
6023 | early_initcall(migration_init); |
6024 | #endif |
6025 | |
6026 | #ifdef CONFIG_SMP |
6027 | |
6028 | #ifdef CONFIG_SCHED_DEBUG |
6029 | |
6030 | static __read_mostly int sched_domain_debug_enabled; |
6031 | |
6032 | static int __init sched_domain_debug_setup(char *str) |
6033 | { |
6034 | sched_domain_debug_enabled = 1; |
6035 | |
6036 | return 0; |
6037 | } |
6038 | early_param("sched_debug", sched_domain_debug_setup); |
6039 | |
6040 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, |
6041 | struct cpumask *groupmask) |
6042 | { |
6043 | struct sched_group *group = sd->groups; |
6044 | char str[256]; |
6045 | |
6046 | cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); |
6047 | cpumask_clear(groupmask); |
6048 | |
6049 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); |
6050 | |
6051 | if (!(sd->flags & SD_LOAD_BALANCE)) { |
6052 | printk("does not load-balance\n"); |
6053 | if (sd->parent) |
6054 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
6055 | " has parent"); |
6056 | return -1; |
6057 | } |
6058 | |
6059 | printk(KERN_CONT "span %s level %s\n", str, sd->name); |
6060 | |
6061 | if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
6062 | printk(KERN_ERR "ERROR: domain->span does not contain " |
6063 | "CPU%d\n", cpu); |
6064 | } |
6065 | if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { |
6066 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
6067 | " CPU%d\n", cpu); |
6068 | } |
6069 | |
6070 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
6071 | do { |
6072 | if (!group) { |
6073 | printk("\n"); |
6074 | printk(KERN_ERR "ERROR: group is NULL\n"); |
6075 | break; |
6076 | } |
6077 | |
6078 | if (!group->cpu_power) { |
6079 | printk(KERN_CONT "\n"); |
6080 | printk(KERN_ERR "ERROR: domain->cpu_power not " |
6081 | "set\n"); |
6082 | break; |
6083 | } |
6084 | |
6085 | if (!cpumask_weight(sched_group_cpus(group))) { |
6086 | printk(KERN_CONT "\n"); |
6087 | printk(KERN_ERR "ERROR: empty group\n"); |
6088 | break; |
6089 | } |
6090 | |
6091 | if (cpumask_intersects(groupmask, sched_group_cpus(group))) { |
6092 | printk(KERN_CONT "\n"); |
6093 | printk(KERN_ERR "ERROR: repeated CPUs\n"); |
6094 | break; |
6095 | } |
6096 | |
6097 | cpumask_or(groupmask, groupmask, sched_group_cpus(group)); |
6098 | |
6099 | cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); |
6100 | |
6101 | printk(KERN_CONT " %s", str); |
6102 | if (group->cpu_power != SCHED_LOAD_SCALE) { |
6103 | printk(KERN_CONT " (cpu_power = %d)", |
6104 | group->cpu_power); |
6105 | } |
6106 | |
6107 | group = group->next; |
6108 | } while (group != sd->groups); |
6109 | printk(KERN_CONT "\n"); |
6110 | |
6111 | if (!cpumask_equal(sched_domain_span(sd), groupmask)) |
6112 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); |
6113 | |
6114 | if (sd->parent && |
6115 | !cpumask_subset(groupmask, sched_domain_span(sd->parent))) |
6116 | printk(KERN_ERR "ERROR: parent span is not a superset " |
6117 | "of domain->span\n"); |
6118 | return 0; |
6119 | } |
6120 | |
6121 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
6122 | { |
6123 | cpumask_var_t groupmask; |
6124 | int level = 0; |
6125 | |
6126 | if (!sched_domain_debug_enabled) |
6127 | return; |
6128 | |
6129 | if (!sd) { |
6130 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); |
6131 | return; |
6132 | } |
6133 | |
6134 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
6135 | |
6136 | if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) { |
6137 | printk(KERN_DEBUG "Cannot load-balance (out of memory)\n"); |
6138 | return; |
6139 | } |
6140 | |
6141 | for (;;) { |
6142 | if (sched_domain_debug_one(sd, cpu, level, groupmask)) |
6143 | break; |
6144 | level++; |
6145 | sd = sd->parent; |
6146 | if (!sd) |
6147 | break; |
6148 | } |
6149 | free_cpumask_var(groupmask); |
6150 | } |
6151 | #else /* !CONFIG_SCHED_DEBUG */ |
6152 | # define sched_domain_debug(sd, cpu) do { } while (0) |
6153 | #endif /* CONFIG_SCHED_DEBUG */ |
6154 | |
6155 | static int sd_degenerate(struct sched_domain *sd) |
6156 | { |
6157 | if (cpumask_weight(sched_domain_span(sd)) == 1) |
6158 | return 1; |
6159 | |
6160 | /* Following flags need at least 2 groups */ |
6161 | if (sd->flags & (SD_LOAD_BALANCE | |
6162 | SD_BALANCE_NEWIDLE | |
6163 | SD_BALANCE_FORK | |
6164 | SD_BALANCE_EXEC | |
6165 | SD_SHARE_CPUPOWER | |
6166 | SD_SHARE_PKG_RESOURCES)) { |
6167 | if (sd->groups != sd->groups->next) |
6168 | return 0; |
6169 | } |
6170 | |
6171 | /* Following flags don't use groups */ |
6172 | if (sd->flags & (SD_WAKE_AFFINE)) |
6173 | return 0; |
6174 | |
6175 | return 1; |
6176 | } |
6177 | |
6178 | static int |
6179 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) |
6180 | { |
6181 | unsigned long cflags = sd->flags, pflags = parent->flags; |
6182 | |
6183 | if (sd_degenerate(parent)) |
6184 | return 1; |
6185 | |
6186 | if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) |
6187 | return 0; |
6188 | |
6189 | /* Flags needing groups don't count if only 1 group in parent */ |
6190 | if (parent->groups == parent->groups->next) { |
6191 | pflags &= ~(SD_LOAD_BALANCE | |
6192 | SD_BALANCE_NEWIDLE | |
6193 | SD_BALANCE_FORK | |
6194 | SD_BALANCE_EXEC | |
6195 | SD_SHARE_CPUPOWER | |
6196 | SD_SHARE_PKG_RESOURCES); |
6197 | if (nr_node_ids == 1) |
6198 | pflags &= ~SD_SERIALIZE; |
6199 | } |
6200 | if (~cflags & pflags) |
6201 | return 0; |
6202 | |
6203 | return 1; |
6204 | } |
6205 | |
6206 | static void free_rootdomain(struct root_domain *rd) |
6207 | { |
6208 | synchronize_sched(); |
6209 | |
6210 | cpupri_cleanup(&rd->cpupri); |
6211 | |
6212 | free_cpumask_var(rd->rto_mask); |
6213 | free_cpumask_var(rd->online); |
6214 | free_cpumask_var(rd->span); |
6215 | kfree(rd); |
6216 | } |
6217 | |
6218 | static void rq_attach_root(struct rq *rq, struct root_domain *rd) |
6219 | { |
6220 | struct root_domain *old_rd = NULL; |
6221 | unsigned long flags; |
6222 | |
6223 | raw_spin_lock_irqsave(&rq->lock, flags); |
6224 | |
6225 | if (rq->rd) { |
6226 | old_rd = rq->rd; |
6227 | |
6228 | if (cpumask_test_cpu(rq->cpu, old_rd->online)) |
6229 | set_rq_offline(rq); |
6230 | |
6231 | cpumask_clear_cpu(rq->cpu, old_rd->span); |
6232 | |
6233 | /* |
6234 | * If we dont want to free the old_rt yet then |
6235 | * set old_rd to NULL to skip the freeing later |
6236 | * in this function: |
6237 | */ |
6238 | if (!atomic_dec_and_test(&old_rd->refcount)) |
6239 | old_rd = NULL; |
6240 | } |
6241 | |
6242 | atomic_inc(&rd->refcount); |
6243 | rq->rd = rd; |
6244 | |
6245 | cpumask_set_cpu(rq->cpu, rd->span); |
6246 | if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) |
6247 | set_rq_online(rq); |
6248 | |
6249 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
6250 | |
6251 | if (old_rd) |
6252 | free_rootdomain(old_rd); |
6253 | } |
6254 | |
6255 | static int init_rootdomain(struct root_domain *rd, bool bootmem) |
6256 | { |
6257 | gfp_t gfp = GFP_KERNEL; |
6258 | |
6259 | memset(rd, 0, sizeof(*rd)); |
6260 | |
6261 | if (bootmem) |
6262 | gfp = GFP_NOWAIT; |
6263 | |
6264 | if (!alloc_cpumask_var(&rd->span, gfp)) |
6265 | goto out; |
6266 | if (!alloc_cpumask_var(&rd->online, gfp)) |
6267 | goto free_span; |
6268 | if (!alloc_cpumask_var(&rd->rto_mask, gfp)) |
6269 | goto free_online; |
6270 | |
6271 | if (cpupri_init(&rd->cpupri, bootmem) != 0) |
6272 | goto free_rto_mask; |
6273 | return 0; |
6274 | |
6275 | free_rto_mask: |
6276 | free_cpumask_var(rd->rto_mask); |
6277 | free_online: |
6278 | free_cpumask_var(rd->online); |
6279 | free_span: |
6280 | free_cpumask_var(rd->span); |
6281 | out: |
6282 | return -ENOMEM; |
6283 | } |
6284 | |
6285 | static void init_defrootdomain(void) |
6286 | { |
6287 | init_rootdomain(&def_root_domain, true); |
6288 | |
6289 | atomic_set(&def_root_domain.refcount, 1); |
6290 | } |
6291 | |
6292 | static struct root_domain *alloc_rootdomain(void) |
6293 | { |
6294 | struct root_domain *rd; |
6295 | |
6296 | rd = kmalloc(sizeof(*rd), GFP_KERNEL); |
6297 | if (!rd) |
6298 | return NULL; |
6299 | |
6300 | if (init_rootdomain(rd, false) != 0) { |
6301 | kfree(rd); |
6302 | return NULL; |
6303 | } |
6304 | |
6305 | return rd; |
6306 | } |
6307 | |
6308 | /* |
6309 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
6310 | * hold the hotplug lock. |
6311 | */ |
6312 | static void |
6313 | cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) |
6314 | { |
6315 | struct rq *rq = cpu_rq(cpu); |
6316 | struct sched_domain *tmp; |
6317 | |
6318 | /* Remove the sched domains which do not contribute to scheduling. */ |
6319 | for (tmp = sd; tmp; ) { |
6320 | struct sched_domain *parent = tmp->parent; |
6321 | if (!parent) |
6322 | break; |
6323 | |
6324 | if (sd_parent_degenerate(tmp, parent)) { |
6325 | tmp->parent = parent->parent; |
6326 | if (parent->parent) |
6327 | parent->parent->child = tmp; |
6328 | } else |
6329 | tmp = tmp->parent; |
6330 | } |
6331 | |
6332 | if (sd && sd_degenerate(sd)) { |
6333 | sd = sd->parent; |
6334 | if (sd) |
6335 | sd->child = NULL; |
6336 | } |
6337 | |
6338 | sched_domain_debug(sd, cpu); |
6339 | |
6340 | rq_attach_root(rq, rd); |
6341 | rcu_assign_pointer(rq->sd, sd); |
6342 | } |
6343 | |
6344 | /* cpus with isolated domains */ |
6345 | static cpumask_var_t cpu_isolated_map; |
6346 | |
6347 | /* Setup the mask of cpus configured for isolated domains */ |
6348 | static int __init isolated_cpu_setup(char *str) |
6349 | { |
6350 | alloc_bootmem_cpumask_var(&cpu_isolated_map); |
6351 | cpulist_parse(str, cpu_isolated_map); |
6352 | return 1; |
6353 | } |
6354 | |
6355 | __setup("isolcpus=", isolated_cpu_setup); |
6356 | |
6357 | /* |
6358 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
6359 | * to a function which identifies what group(along with sched group) a CPU |
6360 | * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids |
6361 | * (due to the fact that we keep track of groups covered with a struct cpumask). |
6362 | * |
6363 | * init_sched_build_groups will build a circular linked list of the groups |
6364 | * covered by the given span, and will set each group's ->cpumask correctly, |
6365 | * and ->cpu_power to 0. |
6366 | */ |
6367 | static void |
6368 | init_sched_build_groups(const struct cpumask *span, |
6369 | const struct cpumask *cpu_map, |
6370 | int (*group_fn)(int cpu, const struct cpumask *cpu_map, |
6371 | struct sched_group **sg, |
6372 | struct cpumask *tmpmask), |
6373 | struct cpumask *covered, struct cpumask *tmpmask) |
6374 | { |
6375 | struct sched_group *first = NULL, *last = NULL; |
6376 | int i; |
6377 | |
6378 | cpumask_clear(covered); |
6379 | |
6380 | for_each_cpu(i, span) { |
6381 | struct sched_group *sg; |
6382 | int group = group_fn(i, cpu_map, &sg, tmpmask); |
6383 | int j; |
6384 | |
6385 | if (cpumask_test_cpu(i, covered)) |
6386 | continue; |
6387 | |
6388 | cpumask_clear(sched_group_cpus(sg)); |
6389 | sg->cpu_power = 0; |
6390 | |
6391 | for_each_cpu(j, span) { |
6392 | if (group_fn(j, cpu_map, NULL, tmpmask) != group) |
6393 | continue; |
6394 | |
6395 | cpumask_set_cpu(j, covered); |
6396 | cpumask_set_cpu(j, sched_group_cpus(sg)); |
6397 | } |
6398 | if (!first) |
6399 | first = sg; |
6400 | if (last) |
6401 | last->next = sg; |
6402 | last = sg; |
6403 | } |
6404 | last->next = first; |
6405 | } |
6406 | |
6407 | #define SD_NODES_PER_DOMAIN 16 |
6408 | |
6409 | #ifdef CONFIG_NUMA |
6410 | |
6411 | /** |
6412 | * find_next_best_node - find the next node to include in a sched_domain |
6413 | * @node: node whose sched_domain we're building |
6414 | * @used_nodes: nodes already in the sched_domain |
6415 | * |
6416 | * Find the next node to include in a given scheduling domain. Simply |
6417 | * finds the closest node not already in the @used_nodes map. |
6418 | * |
6419 | * Should use nodemask_t. |
6420 | */ |
6421 | static int find_next_best_node(int node, nodemask_t *used_nodes) |
6422 | { |
6423 | int i, n, val, min_val, best_node = 0; |
6424 | |
6425 | min_val = INT_MAX; |
6426 | |
6427 | for (i = 0; i < nr_node_ids; i++) { |
6428 | /* Start at @node */ |
6429 | n = (node + i) % nr_node_ids; |
6430 | |
6431 | if (!nr_cpus_node(n)) |
6432 | continue; |
6433 | |
6434 | /* Skip already used nodes */ |
6435 | if (node_isset(n, *used_nodes)) |
6436 | continue; |
6437 | |
6438 | /* Simple min distance search */ |
6439 | val = node_distance(node, n); |
6440 | |
6441 | if (val < min_val) { |
6442 | min_val = val; |
6443 | best_node = n; |
6444 | } |
6445 | } |
6446 | |
6447 | node_set(best_node, *used_nodes); |
6448 | return best_node; |
6449 | } |
6450 | |
6451 | /** |
6452 | * sched_domain_node_span - get a cpumask for a node's sched_domain |
6453 | * @node: node whose cpumask we're constructing |
6454 | * @span: resulting cpumask |
6455 | * |
6456 | * Given a node, construct a good cpumask for its sched_domain to span. It |
6457 | * should be one that prevents unnecessary balancing, but also spreads tasks |
6458 | * out optimally. |
6459 | */ |
6460 | static void sched_domain_node_span(int node, struct cpumask *span) |
6461 | { |
6462 | nodemask_t used_nodes; |
6463 | int i; |
6464 | |
6465 | cpumask_clear(span); |
6466 | nodes_clear(used_nodes); |
6467 | |
6468 | cpumask_or(span, span, cpumask_of_node(node)); |
6469 | node_set(node, used_nodes); |
6470 | |
6471 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { |
6472 | int next_node = find_next_best_node(node, &used_nodes); |
6473 | |
6474 | cpumask_or(span, span, cpumask_of_node(next_node)); |
6475 | } |
6476 | } |
6477 | #endif /* CONFIG_NUMA */ |
6478 | |
6479 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
6480 | |
6481 | /* |
6482 | * The cpus mask in sched_group and sched_domain hangs off the end. |
6483 | * |
6484 | * ( See the the comments in include/linux/sched.h:struct sched_group |
6485 | * and struct sched_domain. ) |
6486 | */ |
6487 | struct static_sched_group { |
6488 | struct sched_group sg; |
6489 | DECLARE_BITMAP(cpus, CONFIG_NR_CPUS); |
6490 | }; |
6491 | |
6492 | struct static_sched_domain { |
6493 | struct sched_domain sd; |
6494 | DECLARE_BITMAP(span, CONFIG_NR_CPUS); |
6495 | }; |
6496 | |
6497 | struct s_data { |
6498 | #ifdef CONFIG_NUMA |
6499 | int sd_allnodes; |
6500 | cpumask_var_t domainspan; |
6501 | cpumask_var_t covered; |
6502 | cpumask_var_t notcovered; |
6503 | #endif |
6504 | cpumask_var_t nodemask; |
6505 | cpumask_var_t this_sibling_map; |
6506 | cpumask_var_t this_core_map; |
6507 | cpumask_var_t send_covered; |
6508 | cpumask_var_t tmpmask; |
6509 | struct sched_group **sched_group_nodes; |
6510 | struct root_domain *rd; |
6511 | }; |
6512 | |
6513 | enum s_alloc { |
6514 | sa_sched_groups = 0, |
6515 | sa_rootdomain, |
6516 | sa_tmpmask, |
6517 | sa_send_covered, |
6518 | sa_this_core_map, |
6519 | sa_this_sibling_map, |
6520 | sa_nodemask, |
6521 | sa_sched_group_nodes, |
6522 | #ifdef CONFIG_NUMA |
6523 | sa_notcovered, |
6524 | sa_covered, |
6525 | sa_domainspan, |
6526 | #endif |
6527 | sa_none, |
6528 | }; |
6529 | |
6530 | /* |
6531 | * SMT sched-domains: |
6532 | */ |
6533 | #ifdef CONFIG_SCHED_SMT |
6534 | static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains); |
6535 | static DEFINE_PER_CPU(struct static_sched_group, sched_groups); |
6536 | |
6537 | static int |
6538 | cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map, |
6539 | struct sched_group **sg, struct cpumask *unused) |
6540 | { |
6541 | if (sg) |
6542 | *sg = &per_cpu(sched_groups, cpu).sg; |
6543 | return cpu; |
6544 | } |
6545 | #endif /* CONFIG_SCHED_SMT */ |
6546 | |
6547 | /* |
6548 | * multi-core sched-domains: |
6549 | */ |
6550 | #ifdef CONFIG_SCHED_MC |
6551 | static DEFINE_PER_CPU(struct static_sched_domain, core_domains); |
6552 | static DEFINE_PER_CPU(struct static_sched_group, sched_group_core); |
6553 | #endif /* CONFIG_SCHED_MC */ |
6554 | |
6555 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) |
6556 | static int |
6557 | cpu_to_core_group(int cpu, const struct cpumask *cpu_map, |
6558 | struct sched_group **sg, struct cpumask *mask) |
6559 | { |
6560 | int group; |
6561 | |
6562 | cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); |
6563 | group = cpumask_first(mask); |
6564 | if (sg) |
6565 | *sg = &per_cpu(sched_group_core, group).sg; |
6566 | return group; |
6567 | } |
6568 | #elif defined(CONFIG_SCHED_MC) |
6569 | static int |
6570 | cpu_to_core_group(int cpu, const struct cpumask *cpu_map, |
6571 | struct sched_group **sg, struct cpumask *unused) |
6572 | { |
6573 | if (sg) |
6574 | *sg = &per_cpu(sched_group_core, cpu).sg; |
6575 | return cpu; |
6576 | } |
6577 | #endif |
6578 | |
6579 | static DEFINE_PER_CPU(struct static_sched_domain, phys_domains); |
6580 | static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys); |
6581 | |
6582 | static int |
6583 | cpu_to_phys_group(int cpu, const struct cpumask *cpu_map, |
6584 | struct sched_group **sg, struct cpumask *mask) |
6585 | { |
6586 | int group; |
6587 | #ifdef CONFIG_SCHED_MC |
6588 | cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map); |
6589 | group = cpumask_first(mask); |
6590 | #elif defined(CONFIG_SCHED_SMT) |
6591 | cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map); |
6592 | group = cpumask_first(mask); |
6593 | #else |
6594 | group = cpu; |
6595 | #endif |
6596 | if (sg) |
6597 | *sg = &per_cpu(sched_group_phys, group).sg; |
6598 | return group; |
6599 | } |
6600 | |
6601 | #ifdef CONFIG_NUMA |
6602 | /* |
6603 | * The init_sched_build_groups can't handle what we want to do with node |
6604 | * groups, so roll our own. Now each node has its own list of groups which |
6605 | * gets dynamically allocated. |
6606 | */ |
6607 | static DEFINE_PER_CPU(struct static_sched_domain, node_domains); |
6608 | static struct sched_group ***sched_group_nodes_bycpu; |
6609 | |
6610 | static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains); |
6611 | static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes); |
6612 | |
6613 | static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map, |
6614 | struct sched_group **sg, |
6615 | struct cpumask *nodemask) |
6616 | { |
6617 | int group; |
6618 | |
6619 | cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map); |
6620 | group = cpumask_first(nodemask); |
6621 | |
6622 | if (sg) |
6623 | *sg = &per_cpu(sched_group_allnodes, group).sg; |
6624 | return group; |
6625 | } |
6626 | |
6627 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
6628 | { |
6629 | struct sched_group *sg = group_head; |
6630 | int j; |
6631 | |
6632 | if (!sg) |
6633 | return; |
6634 | do { |
6635 | for_each_cpu(j, sched_group_cpus(sg)) { |
6636 | struct sched_domain *sd; |
6637 | |
6638 | sd = &per_cpu(phys_domains, j).sd; |
6639 | if (j != group_first_cpu(sd->groups)) { |
6640 | /* |
6641 | * Only add "power" once for each |
6642 | * physical package. |
6643 | */ |
6644 | continue; |
6645 | } |
6646 | |
6647 | sg->cpu_power += sd->groups->cpu_power; |
6648 | } |
6649 | sg = sg->next; |
6650 | } while (sg != group_head); |
6651 | } |
6652 | |
6653 | static int build_numa_sched_groups(struct s_data *d, |
6654 | const struct cpumask *cpu_map, int num) |
6655 | { |
6656 | struct sched_domain *sd; |
6657 | struct sched_group *sg, *prev; |
6658 | int n, j; |
6659 | |
6660 | cpumask_clear(d->covered); |
6661 | cpumask_and(d->nodemask, cpumask_of_node(num), cpu_map); |
6662 | if (cpumask_empty(d->nodemask)) { |
6663 | d->sched_group_nodes[num] = NULL; |
6664 | goto out; |
6665 | } |
6666 | |
6667 | sched_domain_node_span(num, d->domainspan); |
6668 | cpumask_and(d->domainspan, d->domainspan, cpu_map); |
6669 | |
6670 | sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(), |
6671 | GFP_KERNEL, num); |
6672 | if (!sg) { |
6673 | printk(KERN_WARNING "Can not alloc domain group for node %d\n", |
6674 | num); |
6675 | return -ENOMEM; |
6676 | } |
6677 | d->sched_group_nodes[num] = sg; |
6678 | |
6679 | for_each_cpu(j, d->nodemask) { |
6680 | sd = &per_cpu(node_domains, j).sd; |
6681 | sd->groups = sg; |
6682 | } |
6683 | |
6684 | sg->cpu_power = 0; |
6685 | cpumask_copy(sched_group_cpus(sg), d->nodemask); |
6686 | sg->next = sg; |
6687 | cpumask_or(d->covered, d->covered, d->nodemask); |
6688 | |
6689 | prev = sg; |
6690 | for (j = 0; j < nr_node_ids; j++) { |
6691 | n = (num + j) % nr_node_ids; |
6692 | cpumask_complement(d->notcovered, d->covered); |
6693 | cpumask_and(d->tmpmask, d->notcovered, cpu_map); |
6694 | cpumask_and(d->tmpmask, d->tmpmask, d->domainspan); |
6695 | if (cpumask_empty(d->tmpmask)) |
6696 | break; |
6697 | cpumask_and(d->tmpmask, d->tmpmask, cpumask_of_node(n)); |
6698 | if (cpumask_empty(d->tmpmask)) |
6699 | continue; |
6700 | sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(), |
6701 | GFP_KERNEL, num); |
6702 | if (!sg) { |
6703 | printk(KERN_WARNING |
6704 | "Can not alloc domain group for node %d\n", j); |
6705 | return -ENOMEM; |
6706 | } |
6707 | sg->cpu_power = 0; |
6708 | cpumask_copy(sched_group_cpus(sg), d->tmpmask); |
6709 | sg->next = prev->next; |
6710 | cpumask_or(d->covered, d->covered, d->tmpmask); |
6711 | prev->next = sg; |
6712 | prev = sg; |
6713 | } |
6714 | out: |
6715 | return 0; |
6716 | } |
6717 | #endif /* CONFIG_NUMA */ |
6718 | |
6719 | #ifdef CONFIG_NUMA |
6720 | /* Free memory allocated for various sched_group structures */ |
6721 | static void free_sched_groups(const struct cpumask *cpu_map, |
6722 | struct cpumask *nodemask) |
6723 | { |
6724 | int cpu, i; |
6725 | |
6726 | for_each_cpu(cpu, cpu_map) { |
6727 | struct sched_group **sched_group_nodes |
6728 | = sched_group_nodes_bycpu[cpu]; |
6729 | |
6730 | if (!sched_group_nodes) |
6731 | continue; |
6732 | |
6733 | for (i = 0; i < nr_node_ids; i++) { |
6734 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; |
6735 | |
6736 | cpumask_and(nodemask, cpumask_of_node(i), cpu_map); |
6737 | if (cpumask_empty(nodemask)) |
6738 | continue; |
6739 | |
6740 | if (sg == NULL) |
6741 | continue; |
6742 | sg = sg->next; |
6743 | next_sg: |
6744 | oldsg = sg; |
6745 | sg = sg->next; |
6746 | kfree(oldsg); |
6747 | if (oldsg != sched_group_nodes[i]) |
6748 | goto next_sg; |
6749 | } |
6750 | kfree(sched_group_nodes); |
6751 | sched_group_nodes_bycpu[cpu] = NULL; |
6752 | } |
6753 | } |
6754 | #else /* !CONFIG_NUMA */ |
6755 | static void free_sched_groups(const struct cpumask *cpu_map, |
6756 | struct cpumask *nodemask) |
6757 | { |
6758 | } |
6759 | #endif /* CONFIG_NUMA */ |
6760 | |
6761 | /* |
6762 | * Initialize sched groups cpu_power. |
6763 | * |
6764 | * cpu_power indicates the capacity of sched group, which is used while |
6765 | * distributing the load between different sched groups in a sched domain. |
6766 | * Typically cpu_power for all the groups in a sched domain will be same unless |
6767 | * there are asymmetries in the topology. If there are asymmetries, group |
6768 | * having more cpu_power will pickup more load compared to the group having |
6769 | * less cpu_power. |
6770 | */ |
6771 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) |
6772 | { |
6773 | struct sched_domain *child; |
6774 | struct sched_group *group; |
6775 | long power; |
6776 | int weight; |
6777 | |
6778 | WARN_ON(!sd || !sd->groups); |
6779 | |
6780 | if (cpu != group_first_cpu(sd->groups)) |
6781 | return; |
6782 | |
6783 | child = sd->child; |
6784 | |
6785 | sd->groups->cpu_power = 0; |
6786 | |
6787 | if (!child) { |
6788 | power = SCHED_LOAD_SCALE; |
6789 | weight = cpumask_weight(sched_domain_span(sd)); |
6790 | /* |
6791 | * SMT siblings share the power of a single core. |
6792 | * Usually multiple threads get a better yield out of |
6793 | * that one core than a single thread would have, |
6794 | * reflect that in sd->smt_gain. |
6795 | */ |
6796 | if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { |
6797 | power *= sd->smt_gain; |
6798 | power /= weight; |
6799 | power >>= SCHED_LOAD_SHIFT; |
6800 | } |
6801 | sd->groups->cpu_power += power; |
6802 | return; |
6803 | } |
6804 | |
6805 | /* |
6806 | * Add cpu_power of each child group to this groups cpu_power. |
6807 | */ |
6808 | group = child->groups; |
6809 | do { |
6810 | sd->groups->cpu_power += group->cpu_power; |
6811 | group = group->next; |
6812 | } while (group != child->groups); |
6813 | } |
6814 | |
6815 | /* |
6816 | * Initializers for schedule domains |
6817 | * Non-inlined to reduce accumulated stack pressure in build_sched_domains() |
6818 | */ |
6819 | |
6820 | #ifdef CONFIG_SCHED_DEBUG |
6821 | # define SD_INIT_NAME(sd, type) sd->name = #type |
6822 | #else |
6823 | # define SD_INIT_NAME(sd, type) do { } while (0) |
6824 | #endif |
6825 | |
6826 | #define SD_INIT(sd, type) sd_init_##type(sd) |
6827 | |
6828 | #define SD_INIT_FUNC(type) \ |
6829 | static noinline void sd_init_##type(struct sched_domain *sd) \ |
6830 | { \ |
6831 | memset(sd, 0, sizeof(*sd)); \ |
6832 | *sd = SD_##type##_INIT; \ |
6833 | sd->level = SD_LV_##type; \ |
6834 | SD_INIT_NAME(sd, type); \ |
6835 | } |
6836 | |
6837 | SD_INIT_FUNC(CPU) |
6838 | #ifdef CONFIG_NUMA |
6839 | SD_INIT_FUNC(ALLNODES) |
6840 | SD_INIT_FUNC(NODE) |
6841 | #endif |
6842 | #ifdef CONFIG_SCHED_SMT |
6843 | SD_INIT_FUNC(SIBLING) |
6844 | #endif |
6845 | #ifdef CONFIG_SCHED_MC |
6846 | SD_INIT_FUNC(MC) |
6847 | #endif |
6848 | |
6849 | static int default_relax_domain_level = -1; |
6850 | |
6851 | static int __init setup_relax_domain_level(char *str) |
6852 | { |
6853 | unsigned long val; |
6854 | |
6855 | val = simple_strtoul(str, NULL, 0); |
6856 | if (val < SD_LV_MAX) |
6857 | default_relax_domain_level = val; |
6858 | |
6859 | return 1; |
6860 | } |
6861 | __setup("relax_domain_level=", setup_relax_domain_level); |
6862 | |
6863 | static void set_domain_attribute(struct sched_domain *sd, |
6864 | struct sched_domain_attr *attr) |
6865 | { |
6866 | int request; |
6867 | |
6868 | if (!attr || attr->relax_domain_level < 0) { |
6869 | if (default_relax_domain_level < 0) |
6870 | return; |
6871 | else |
6872 | request = default_relax_domain_level; |
6873 | } else |
6874 | request = attr->relax_domain_level; |
6875 | if (request < sd->level) { |
6876 | /* turn off idle balance on this domain */ |
6877 | sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
6878 | } else { |
6879 | /* turn on idle balance on this domain */ |
6880 | sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
6881 | } |
6882 | } |
6883 | |
6884 | static void __free_domain_allocs(struct s_data *d, enum s_alloc what, |
6885 | const struct cpumask *cpu_map) |
6886 | { |
6887 | switch (what) { |
6888 | case sa_sched_groups: |
6889 | free_sched_groups(cpu_map, d->tmpmask); /* fall through */ |
6890 | d->sched_group_nodes = NULL; |
6891 | case sa_rootdomain: |
6892 | free_rootdomain(d->rd); /* fall through */ |
6893 | case sa_tmpmask: |
6894 | free_cpumask_var(d->tmpmask); /* fall through */ |
6895 | case sa_send_covered: |
6896 | free_cpumask_var(d->send_covered); /* fall through */ |
6897 | case sa_this_core_map: |
6898 | free_cpumask_var(d->this_core_map); /* fall through */ |
6899 | case sa_this_sibling_map: |
6900 | free_cpumask_var(d->this_sibling_map); /* fall through */ |
6901 | case sa_nodemask: |
6902 | free_cpumask_var(d->nodemask); /* fall through */ |
6903 | case sa_sched_group_nodes: |
6904 | #ifdef CONFIG_NUMA |
6905 | kfree(d->sched_group_nodes); /* fall through */ |
6906 | case sa_notcovered: |
6907 | free_cpumask_var(d->notcovered); /* fall through */ |
6908 | case sa_covered: |
6909 | free_cpumask_var(d->covered); /* fall through */ |
6910 | case sa_domainspan: |
6911 | free_cpumask_var(d->domainspan); /* fall through */ |
6912 | #endif |
6913 | case sa_none: |
6914 | break; |
6915 | } |
6916 | } |
6917 | |
6918 | static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, |
6919 | const struct cpumask *cpu_map) |
6920 | { |
6921 | #ifdef CONFIG_NUMA |
6922 | if (!alloc_cpumask_var(&d->domainspan, GFP_KERNEL)) |
6923 | return sa_none; |
6924 | if (!alloc_cpumask_var(&d->covered, GFP_KERNEL)) |
6925 | return sa_domainspan; |
6926 | if (!alloc_cpumask_var(&d->notcovered, GFP_KERNEL)) |
6927 | return sa_covered; |
6928 | /* Allocate the per-node list of sched groups */ |
6929 | d->sched_group_nodes = kcalloc(nr_node_ids, |
6930 | sizeof(struct sched_group *), GFP_KERNEL); |
6931 | if (!d->sched_group_nodes) { |
6932 | printk(KERN_WARNING "Can not alloc sched group node list\n"); |
6933 | return sa_notcovered; |
6934 | } |
6935 | sched_group_nodes_bycpu[cpumask_first(cpu_map)] = d->sched_group_nodes; |
6936 | #endif |
6937 | if (!alloc_cpumask_var(&d->nodemask, GFP_KERNEL)) |
6938 | return sa_sched_group_nodes; |
6939 | if (!alloc_cpumask_var(&d->this_sibling_map, GFP_KERNEL)) |
6940 | return sa_nodemask; |
6941 | if (!alloc_cpumask_var(&d->this_core_map, GFP_KERNEL)) |
6942 | return sa_this_sibling_map; |
6943 | if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL)) |
6944 | return sa_this_core_map; |
6945 | if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL)) |
6946 | return sa_send_covered; |
6947 | d->rd = alloc_rootdomain(); |
6948 | if (!d->rd) { |
6949 | printk(KERN_WARNING "Cannot alloc root domain\n"); |
6950 | return sa_tmpmask; |
6951 | } |
6952 | return sa_rootdomain; |
6953 | } |
6954 | |
6955 | static struct sched_domain *__build_numa_sched_domains(struct s_data *d, |
6956 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, int i) |
6957 | { |
6958 | struct sched_domain *sd = NULL; |
6959 | #ifdef CONFIG_NUMA |
6960 | struct sched_domain *parent; |
6961 | |
6962 | d->sd_allnodes = 0; |
6963 | if (cpumask_weight(cpu_map) > |
6964 | SD_NODES_PER_DOMAIN * cpumask_weight(d->nodemask)) { |
6965 | sd = &per_cpu(allnodes_domains, i).sd; |
6966 | SD_INIT(sd, ALLNODES); |
6967 | set_domain_attribute(sd, attr); |
6968 | cpumask_copy(sched_domain_span(sd), cpu_map); |
6969 | cpu_to_allnodes_group(i, cpu_map, &sd->groups, d->tmpmask); |
6970 | d->sd_allnodes = 1; |
6971 | } |
6972 | parent = sd; |
6973 | |
6974 | sd = &per_cpu(node_domains, i).sd; |
6975 | SD_INIT(sd, NODE); |
6976 | set_domain_attribute(sd, attr); |
6977 | sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd)); |
6978 | sd->parent = parent; |
6979 | if (parent) |
6980 | parent->child = sd; |
6981 | cpumask_and(sched_domain_span(sd), sched_domain_span(sd), cpu_map); |
6982 | #endif |
6983 | return sd; |
6984 | } |
6985 | |
6986 | static struct sched_domain *__build_cpu_sched_domain(struct s_data *d, |
6987 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
6988 | struct sched_domain *parent, int i) |
6989 | { |
6990 | struct sched_domain *sd; |
6991 | sd = &per_cpu(phys_domains, i).sd; |
6992 | SD_INIT(sd, CPU); |
6993 | set_domain_attribute(sd, attr); |
6994 | cpumask_copy(sched_domain_span(sd), d->nodemask); |
6995 | sd->parent = parent; |
6996 | if (parent) |
6997 | parent->child = sd; |
6998 | cpu_to_phys_group(i, cpu_map, &sd->groups, d->tmpmask); |
6999 | return sd; |
7000 | } |
7001 | |
7002 | static struct sched_domain *__build_mc_sched_domain(struct s_data *d, |
7003 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
7004 | struct sched_domain *parent, int i) |
7005 | { |
7006 | struct sched_domain *sd = parent; |
7007 | #ifdef CONFIG_SCHED_MC |
7008 | sd = &per_cpu(core_domains, i).sd; |
7009 | SD_INIT(sd, MC); |
7010 | set_domain_attribute(sd, attr); |
7011 | cpumask_and(sched_domain_span(sd), cpu_map, cpu_coregroup_mask(i)); |
7012 | sd->parent = parent; |
7013 | parent->child = sd; |
7014 | cpu_to_core_group(i, cpu_map, &sd->groups, d->tmpmask); |
7015 | #endif |
7016 | return sd; |
7017 | } |
7018 | |
7019 | static struct sched_domain *__build_smt_sched_domain(struct s_data *d, |
7020 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
7021 | struct sched_domain *parent, int i) |
7022 | { |
7023 | struct sched_domain *sd = parent; |
7024 | #ifdef CONFIG_SCHED_SMT |
7025 | sd = &per_cpu(cpu_domains, i).sd; |
7026 | SD_INIT(sd, SIBLING); |
7027 | set_domain_attribute(sd, attr); |
7028 | cpumask_and(sched_domain_span(sd), cpu_map, topology_thread_cpumask(i)); |
7029 | sd->parent = parent; |
7030 | parent->child = sd; |
7031 | cpu_to_cpu_group(i, cpu_map, &sd->groups, d->tmpmask); |
7032 | #endif |
7033 | return sd; |
7034 | } |
7035 | |
7036 | static void build_sched_groups(struct s_data *d, enum sched_domain_level l, |
7037 | const struct cpumask *cpu_map, int cpu) |
7038 | { |
7039 | switch (l) { |
7040 | #ifdef CONFIG_SCHED_SMT |
7041 | case SD_LV_SIBLING: /* set up CPU (sibling) groups */ |
7042 | cpumask_and(d->this_sibling_map, cpu_map, |
7043 | topology_thread_cpumask(cpu)); |
7044 | if (cpu == cpumask_first(d->this_sibling_map)) |
7045 | init_sched_build_groups(d->this_sibling_map, cpu_map, |
7046 | &cpu_to_cpu_group, |
7047 | d->send_covered, d->tmpmask); |
7048 | break; |
7049 | #endif |
7050 | #ifdef CONFIG_SCHED_MC |
7051 | case SD_LV_MC: /* set up multi-core groups */ |
7052 | cpumask_and(d->this_core_map, cpu_map, cpu_coregroup_mask(cpu)); |
7053 | if (cpu == cpumask_first(d->this_core_map)) |
7054 | init_sched_build_groups(d->this_core_map, cpu_map, |
7055 | &cpu_to_core_group, |
7056 | d->send_covered, d->tmpmask); |
7057 | break; |
7058 | #endif |
7059 | case SD_LV_CPU: /* set up physical groups */ |
7060 | cpumask_and(d->nodemask, cpumask_of_node(cpu), cpu_map); |
7061 | if (!cpumask_empty(d->nodemask)) |
7062 | init_sched_build_groups(d->nodemask, cpu_map, |
7063 | &cpu_to_phys_group, |
7064 | d->send_covered, d->tmpmask); |
7065 | break; |
7066 | #ifdef CONFIG_NUMA |
7067 | case SD_LV_ALLNODES: |
7068 | init_sched_build_groups(cpu_map, cpu_map, &cpu_to_allnodes_group, |
7069 | d->send_covered, d->tmpmask); |
7070 | break; |
7071 | #endif |
7072 | default: |
7073 | break; |
7074 | } |
7075 | } |
7076 | |
7077 | /* |
7078 | * Build sched domains for a given set of cpus and attach the sched domains |
7079 | * to the individual cpus |
7080 | */ |
7081 | static int __build_sched_domains(const struct cpumask *cpu_map, |
7082 | struct sched_domain_attr *attr) |
7083 | { |
7084 | enum s_alloc alloc_state = sa_none; |
7085 | struct s_data d; |
7086 | struct sched_domain *sd; |
7087 | int i; |
7088 | #ifdef CONFIG_NUMA |
7089 | d.sd_allnodes = 0; |
7090 | #endif |
7091 | |
7092 | alloc_state = __visit_domain_allocation_hell(&d, cpu_map); |
7093 | if (alloc_state != sa_rootdomain) |
7094 | goto error; |
7095 | alloc_state = sa_sched_groups; |
7096 | |
7097 | /* |
7098 | * Set up domains for cpus specified by the cpu_map. |
7099 | */ |
7100 | for_each_cpu(i, cpu_map) { |
7101 | cpumask_and(d.nodemask, cpumask_of_node(cpu_to_node(i)), |
7102 | cpu_map); |
7103 | |
7104 | sd = __build_numa_sched_domains(&d, cpu_map, attr, i); |
7105 | sd = __build_cpu_sched_domain(&d, cpu_map, attr, sd, i); |
7106 | sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i); |
7107 | sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i); |
7108 | } |
7109 | |
7110 | for_each_cpu(i, cpu_map) { |
7111 | build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i); |
7112 | build_sched_groups(&d, SD_LV_MC, cpu_map, i); |
7113 | } |
7114 | |
7115 | /* Set up physical groups */ |
7116 | for (i = 0; i < nr_node_ids; i++) |
7117 | build_sched_groups(&d, SD_LV_CPU, cpu_map, i); |
7118 | |
7119 | #ifdef CONFIG_NUMA |
7120 | /* Set up node groups */ |
7121 | if (d.sd_allnodes) |
7122 | build_sched_groups(&d, SD_LV_ALLNODES, cpu_map, 0); |
7123 | |
7124 | for (i = 0; i < nr_node_ids; i++) |
7125 | if (build_numa_sched_groups(&d, cpu_map, i)) |
7126 | goto error; |
7127 | #endif |
7128 | |
7129 | /* Calculate CPU power for physical packages and nodes */ |
7130 | #ifdef CONFIG_SCHED_SMT |
7131 | for_each_cpu(i, cpu_map) { |
7132 | sd = &per_cpu(cpu_domains, i).sd; |
7133 | init_sched_groups_power(i, sd); |
7134 | } |
7135 | #endif |
7136 | #ifdef CONFIG_SCHED_MC |
7137 | for_each_cpu(i, cpu_map) { |
7138 | sd = &per_cpu(core_domains, i).sd; |
7139 | init_sched_groups_power(i, sd); |
7140 | } |
7141 | #endif |
7142 | |
7143 | for_each_cpu(i, cpu_map) { |
7144 | sd = &per_cpu(phys_domains, i).sd; |
7145 | init_sched_groups_power(i, sd); |
7146 | } |
7147 | |
7148 | #ifdef CONFIG_NUMA |
7149 | for (i = 0; i < nr_node_ids; i++) |
7150 | init_numa_sched_groups_power(d.sched_group_nodes[i]); |
7151 | |
7152 | if (d.sd_allnodes) { |
7153 | struct sched_group *sg; |
7154 | |
7155 | cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg, |
7156 | d.tmpmask); |
7157 | init_numa_sched_groups_power(sg); |
7158 | } |
7159 | #endif |
7160 | |
7161 | /* Attach the domains */ |
7162 | for_each_cpu(i, cpu_map) { |
7163 | #ifdef CONFIG_SCHED_SMT |
7164 | sd = &per_cpu(cpu_domains, i).sd; |
7165 | #elif defined(CONFIG_SCHED_MC) |
7166 | sd = &per_cpu(core_domains, i).sd; |
7167 | #else |
7168 | sd = &per_cpu(phys_domains, i).sd; |
7169 | #endif |
7170 | cpu_attach_domain(sd, d.rd, i); |
7171 | } |
7172 | |
7173 | d.sched_group_nodes = NULL; /* don't free this we still need it */ |
7174 | __free_domain_allocs(&d, sa_tmpmask, cpu_map); |
7175 | return 0; |
7176 | |
7177 | error: |
7178 | __free_domain_allocs(&d, alloc_state, cpu_map); |
7179 | return -ENOMEM; |
7180 | } |
7181 | |
7182 | static int build_sched_domains(const struct cpumask *cpu_map) |
7183 | { |
7184 | return __build_sched_domains(cpu_map, NULL); |
7185 | } |
7186 | |
7187 | static cpumask_var_t *doms_cur; /* current sched domains */ |
7188 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ |
7189 | static struct sched_domain_attr *dattr_cur; |
7190 | /* attribues of custom domains in 'doms_cur' */ |
7191 | |
7192 | /* |
7193 | * Special case: If a kmalloc of a doms_cur partition (array of |
7194 | * cpumask) fails, then fallback to a single sched domain, |
7195 | * as determined by the single cpumask fallback_doms. |
7196 | */ |
7197 | static cpumask_var_t fallback_doms; |
7198 | |
7199 | /* |
7200 | * arch_update_cpu_topology lets virtualized architectures update the |
7201 | * cpu core maps. It is supposed to return 1 if the topology changed |
7202 | * or 0 if it stayed the same. |
7203 | */ |
7204 | int __attribute__((weak)) arch_update_cpu_topology(void) |
7205 | { |
7206 | return 0; |
7207 | } |
7208 | |
7209 | cpumask_var_t *alloc_sched_domains(unsigned int ndoms) |
7210 | { |
7211 | int i; |
7212 | cpumask_var_t *doms; |
7213 | |
7214 | doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); |
7215 | if (!doms) |
7216 | return NULL; |
7217 | for (i = 0; i < ndoms; i++) { |
7218 | if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { |
7219 | free_sched_domains(doms, i); |
7220 | return NULL; |
7221 | } |
7222 | } |
7223 | return doms; |
7224 | } |
7225 | |
7226 | void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) |
7227 | { |
7228 | unsigned int i; |
7229 | for (i = 0; i < ndoms; i++) |
7230 | free_cpumask_var(doms[i]); |
7231 | kfree(doms); |
7232 | } |
7233 | |
7234 | /* |
7235 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
7236 | * For now this just excludes isolated cpus, but could be used to |
7237 | * exclude other special cases in the future. |
7238 | */ |
7239 | static int arch_init_sched_domains(const struct cpumask *cpu_map) |
7240 | { |
7241 | int err; |
7242 | |
7243 | arch_update_cpu_topology(); |
7244 | ndoms_cur = 1; |
7245 | doms_cur = alloc_sched_domains(ndoms_cur); |
7246 | if (!doms_cur) |
7247 | doms_cur = &fallback_doms; |
7248 | cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); |
7249 | dattr_cur = NULL; |
7250 | err = build_sched_domains(doms_cur[0]); |
7251 | register_sched_domain_sysctl(); |
7252 | |
7253 | return err; |
7254 | } |
7255 | |
7256 | static void arch_destroy_sched_domains(const struct cpumask *cpu_map, |
7257 | struct cpumask *tmpmask) |
7258 | { |
7259 | free_sched_groups(cpu_map, tmpmask); |
7260 | } |
7261 | |
7262 | /* |
7263 | * Detach sched domains from a group of cpus specified in cpu_map |
7264 | * These cpus will now be attached to the NULL domain |
7265 | */ |
7266 | static void detach_destroy_domains(const struct cpumask *cpu_map) |
7267 | { |
7268 | /* Save because hotplug lock held. */ |
7269 | static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS); |
7270 | int i; |
7271 | |
7272 | for_each_cpu(i, cpu_map) |
7273 | cpu_attach_domain(NULL, &def_root_domain, i); |
7274 | synchronize_sched(); |
7275 | arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask)); |
7276 | } |
7277 | |
7278 | /* handle null as "default" */ |
7279 | static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, |
7280 | struct sched_domain_attr *new, int idx_new) |
7281 | { |
7282 | struct sched_domain_attr tmp; |
7283 | |
7284 | /* fast path */ |
7285 | if (!new && !cur) |
7286 | return 1; |
7287 | |
7288 | tmp = SD_ATTR_INIT; |
7289 | return !memcmp(cur ? (cur + idx_cur) : &tmp, |
7290 | new ? (new + idx_new) : &tmp, |
7291 | sizeof(struct sched_domain_attr)); |
7292 | } |
7293 | |
7294 | /* |
7295 | * Partition sched domains as specified by the 'ndoms_new' |
7296 | * cpumasks in the array doms_new[] of cpumasks. This compares |
7297 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
7298 | * It destroys each deleted domain and builds each new domain. |
7299 | * |
7300 | * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. |
7301 | * The masks don't intersect (don't overlap.) We should setup one |
7302 | * sched domain for each mask. CPUs not in any of the cpumasks will |
7303 | * not be load balanced. If the same cpumask appears both in the |
7304 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
7305 | * it as it is. |
7306 | * |
7307 | * The passed in 'doms_new' should be allocated using |
7308 | * alloc_sched_domains. This routine takes ownership of it and will |
7309 | * free_sched_domains it when done with it. If the caller failed the |
7310 | * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, |
7311 | * and partition_sched_domains() will fallback to the single partition |
7312 | * 'fallback_doms', it also forces the domains to be rebuilt. |
7313 | * |
7314 | * If doms_new == NULL it will be replaced with cpu_online_mask. |
7315 | * ndoms_new == 0 is a special case for destroying existing domains, |
7316 | * and it will not create the default domain. |
7317 | * |
7318 | * Call with hotplug lock held |
7319 | */ |
7320 | void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], |
7321 | struct sched_domain_attr *dattr_new) |
7322 | { |
7323 | int i, j, n; |
7324 | int new_topology; |
7325 | |
7326 | mutex_lock(&sched_domains_mutex); |
7327 | |
7328 | /* always unregister in case we don't destroy any domains */ |
7329 | unregister_sched_domain_sysctl(); |
7330 | |
7331 | /* Let architecture update cpu core mappings. */ |
7332 | new_topology = arch_update_cpu_topology(); |
7333 | |
7334 | n = doms_new ? ndoms_new : 0; |
7335 | |
7336 | /* Destroy deleted domains */ |
7337 | for (i = 0; i < ndoms_cur; i++) { |
7338 | for (j = 0; j < n && !new_topology; j++) { |
7339 | if (cpumask_equal(doms_cur[i], doms_new[j]) |
7340 | && dattrs_equal(dattr_cur, i, dattr_new, j)) |
7341 | goto match1; |
7342 | } |
7343 | /* no match - a current sched domain not in new doms_new[] */ |
7344 | detach_destroy_domains(doms_cur[i]); |
7345 | match1: |
7346 | ; |
7347 | } |
7348 | |
7349 | if (doms_new == NULL) { |
7350 | ndoms_cur = 0; |
7351 | doms_new = &fallback_doms; |
7352 | cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); |
7353 | WARN_ON_ONCE(dattr_new); |
7354 | } |
7355 | |
7356 | /* Build new domains */ |
7357 | for (i = 0; i < ndoms_new; i++) { |
7358 | for (j = 0; j < ndoms_cur && !new_topology; j++) { |
7359 | if (cpumask_equal(doms_new[i], doms_cur[j]) |
7360 | && dattrs_equal(dattr_new, i, dattr_cur, j)) |
7361 | goto match2; |
7362 | } |
7363 | /* no match - add a new doms_new */ |
7364 | __build_sched_domains(doms_new[i], |
7365 | dattr_new ? dattr_new + i : NULL); |
7366 | match2: |
7367 | ; |
7368 | } |
7369 | |
7370 | /* Remember the new sched domains */ |
7371 | if (doms_cur != &fallback_doms) |
7372 | free_sched_domains(doms_cur, ndoms_cur); |
7373 | kfree(dattr_cur); /* kfree(NULL) is safe */ |
7374 | doms_cur = doms_new; |
7375 | dattr_cur = dattr_new; |
7376 | ndoms_cur = ndoms_new; |
7377 | |
7378 | register_sched_domain_sysctl(); |
7379 | |
7380 | mutex_unlock(&sched_domains_mutex); |
7381 | } |
7382 | |
7383 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
7384 | static void arch_reinit_sched_domains(void) |
7385 | { |
7386 | get_online_cpus(); |
7387 | |
7388 | /* Destroy domains first to force the rebuild */ |
7389 | partition_sched_domains(0, NULL, NULL); |
7390 | |
7391 | rebuild_sched_domains(); |
7392 | put_online_cpus(); |
7393 | } |
7394 | |
7395 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) |
7396 | { |
7397 | unsigned int level = 0; |
7398 | |
7399 | if (sscanf(buf, "%u", &level) != 1) |
7400 | return -EINVAL; |
7401 | |
7402 | /* |
7403 | * level is always be positive so don't check for |
7404 | * level < POWERSAVINGS_BALANCE_NONE which is 0 |
7405 | * What happens on 0 or 1 byte write, |
7406 | * need to check for count as well? |
7407 | */ |
7408 | |
7409 | if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS) |
7410 | return -EINVAL; |
7411 | |
7412 | if (smt) |
7413 | sched_smt_power_savings = level; |
7414 | else |
7415 | sched_mc_power_savings = level; |
7416 | |
7417 | arch_reinit_sched_domains(); |
7418 | |
7419 | return count; |
7420 | } |
7421 | |
7422 | #ifdef CONFIG_SCHED_MC |
7423 | static ssize_t sched_mc_power_savings_show(struct sysdev_class *class, |
7424 | struct sysdev_class_attribute *attr, |
7425 | char *page) |
7426 | { |
7427 | return sprintf(page, "%u\n", sched_mc_power_savings); |
7428 | } |
7429 | static ssize_t sched_mc_power_savings_store(struct sysdev_class *class, |
7430 | struct sysdev_class_attribute *attr, |
7431 | const char *buf, size_t count) |
7432 | { |
7433 | return sched_power_savings_store(buf, count, 0); |
7434 | } |
7435 | static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644, |
7436 | sched_mc_power_savings_show, |
7437 | sched_mc_power_savings_store); |
7438 | #endif |
7439 | |
7440 | #ifdef CONFIG_SCHED_SMT |
7441 | static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev, |
7442 | struct sysdev_class_attribute *attr, |
7443 | char *page) |
7444 | { |
7445 | return sprintf(page, "%u\n", sched_smt_power_savings); |
7446 | } |
7447 | static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev, |
7448 | struct sysdev_class_attribute *attr, |
7449 | const char *buf, size_t count) |
7450 | { |
7451 | return sched_power_savings_store(buf, count, 1); |
7452 | } |
7453 | static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644, |
7454 | sched_smt_power_savings_show, |
7455 | sched_smt_power_savings_store); |
7456 | #endif |
7457 | |
7458 | int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) |
7459 | { |
7460 | int err = 0; |
7461 | |
7462 | #ifdef CONFIG_SCHED_SMT |
7463 | if (smt_capable()) |
7464 | err = sysfs_create_file(&cls->kset.kobj, |
7465 | &attr_sched_smt_power_savings.attr); |
7466 | #endif |
7467 | #ifdef CONFIG_SCHED_MC |
7468 | if (!err && mc_capable()) |
7469 | err = sysfs_create_file(&cls->kset.kobj, |
7470 | &attr_sched_mc_power_savings.attr); |
7471 | #endif |
7472 | return err; |
7473 | } |
7474 | #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ |
7475 | |
7476 | #ifndef CONFIG_CPUSETS |
7477 | /* |
7478 | * Add online and remove offline CPUs from the scheduler domains. |
7479 | * When cpusets are enabled they take over this function. |
7480 | */ |
7481 | static int update_sched_domains(struct notifier_block *nfb, |
7482 | unsigned long action, void *hcpu) |
7483 | { |
7484 | switch (action) { |
7485 | case CPU_ONLINE: |
7486 | case CPU_ONLINE_FROZEN: |
7487 | case CPU_DOWN_PREPARE: |
7488 | case CPU_DOWN_PREPARE_FROZEN: |
7489 | case CPU_DOWN_FAILED: |
7490 | case CPU_DOWN_FAILED_FROZEN: |
7491 | partition_sched_domains(1, NULL, NULL); |
7492 | return NOTIFY_OK; |
7493 | |
7494 | default: |
7495 | return NOTIFY_DONE; |
7496 | } |
7497 | } |
7498 | #endif |
7499 | |
7500 | static int update_runtime(struct notifier_block *nfb, |
7501 | unsigned long action, void *hcpu) |
7502 | { |
7503 | int cpu = (int)(long)hcpu; |
7504 | |
7505 | switch (action) { |
7506 | case CPU_DOWN_PREPARE: |
7507 | case CPU_DOWN_PREPARE_FROZEN: |
7508 | disable_runtime(cpu_rq(cpu)); |
7509 | return NOTIFY_OK; |
7510 | |
7511 | case CPU_DOWN_FAILED: |
7512 | case CPU_DOWN_FAILED_FROZEN: |
7513 | case CPU_ONLINE: |
7514 | case CPU_ONLINE_FROZEN: |
7515 | enable_runtime(cpu_rq(cpu)); |
7516 | return NOTIFY_OK; |
7517 | |
7518 | default: |
7519 | return NOTIFY_DONE; |
7520 | } |
7521 | } |
7522 | |
7523 | void __init sched_init_smp(void) |
7524 | { |
7525 | cpumask_var_t non_isolated_cpus; |
7526 | |
7527 | alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); |
7528 | alloc_cpumask_var(&fallback_doms, GFP_KERNEL); |
7529 | |
7530 | #if defined(CONFIG_NUMA) |
7531 | sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **), |
7532 | GFP_KERNEL); |
7533 | BUG_ON(sched_group_nodes_bycpu == NULL); |
7534 | #endif |
7535 | get_online_cpus(); |
7536 | mutex_lock(&sched_domains_mutex); |
7537 | arch_init_sched_domains(cpu_active_mask); |
7538 | cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); |
7539 | if (cpumask_empty(non_isolated_cpus)) |
7540 | cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); |
7541 | mutex_unlock(&sched_domains_mutex); |
7542 | put_online_cpus(); |
7543 | |
7544 | #ifndef CONFIG_CPUSETS |
7545 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
7546 | hotcpu_notifier(update_sched_domains, 0); |
7547 | #endif |
7548 | |
7549 | /* RT runtime code needs to handle some hotplug events */ |
7550 | hotcpu_notifier(update_runtime, 0); |
7551 | |
7552 | init_hrtick(); |
7553 | |
7554 | /* Move init over to a non-isolated CPU */ |
7555 | if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) |
7556 | BUG(); |
7557 | sched_init_granularity(); |
7558 | free_cpumask_var(non_isolated_cpus); |
7559 | |
7560 | init_sched_rt_class(); |
7561 | } |
7562 | #else |
7563 | void __init sched_init_smp(void) |
7564 | { |
7565 | sched_init_granularity(); |
7566 | } |
7567 | #endif /* CONFIG_SMP */ |
7568 | |
7569 | const_debug unsigned int sysctl_timer_migration = 1; |
7570 | |
7571 | int in_sched_functions(unsigned long addr) |
7572 | { |
7573 | return in_lock_functions(addr) || |
7574 | (addr >= (unsigned long)__sched_text_start |
7575 | && addr < (unsigned long)__sched_text_end); |
7576 | } |
7577 | |
7578 | static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
7579 | { |
7580 | cfs_rq->tasks_timeline = RB_ROOT; |
7581 | INIT_LIST_HEAD(&cfs_rq->tasks); |
7582 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7583 | cfs_rq->rq = rq; |
7584 | #endif |
7585 | cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
7586 | } |
7587 | |
7588 | static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq) |
7589 | { |
7590 | struct rt_prio_array *array; |
7591 | int i; |
7592 | |
7593 | array = &rt_rq->active; |
7594 | for (i = 0; i < MAX_RT_PRIO; i++) { |
7595 | INIT_LIST_HEAD(array->queue + i); |
7596 | __clear_bit(i, array->bitmap); |
7597 | } |
7598 | /* delimiter for bitsearch: */ |
7599 | __set_bit(MAX_RT_PRIO, array->bitmap); |
7600 | |
7601 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
7602 | rt_rq->highest_prio.curr = MAX_RT_PRIO; |
7603 | #ifdef CONFIG_SMP |
7604 | rt_rq->highest_prio.next = MAX_RT_PRIO; |
7605 | #endif |
7606 | #endif |
7607 | #ifdef CONFIG_SMP |
7608 | rt_rq->rt_nr_migratory = 0; |
7609 | rt_rq->overloaded = 0; |
7610 | plist_head_init_raw(&rt_rq->pushable_tasks, &rq->lock); |
7611 | #endif |
7612 | |
7613 | rt_rq->rt_time = 0; |
7614 | rt_rq->rt_throttled = 0; |
7615 | rt_rq->rt_runtime = 0; |
7616 | raw_spin_lock_init(&rt_rq->rt_runtime_lock); |
7617 | |
7618 | #ifdef CONFIG_RT_GROUP_SCHED |
7619 | rt_rq->rt_nr_boosted = 0; |
7620 | rt_rq->rq = rq; |
7621 | #endif |
7622 | } |
7623 | |
7624 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7625 | static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, |
7626 | struct sched_entity *se, int cpu, int add, |
7627 | struct sched_entity *parent) |
7628 | { |
7629 | struct rq *rq = cpu_rq(cpu); |
7630 | tg->cfs_rq[cpu] = cfs_rq; |
7631 | init_cfs_rq(cfs_rq, rq); |
7632 | cfs_rq->tg = tg; |
7633 | if (add) |
7634 | list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); |
7635 | |
7636 | tg->se[cpu] = se; |
7637 | /* se could be NULL for init_task_group */ |
7638 | if (!se) |
7639 | return; |
7640 | |
7641 | if (!parent) |
7642 | se->cfs_rq = &rq->cfs; |
7643 | else |
7644 | se->cfs_rq = parent->my_q; |
7645 | |
7646 | se->my_q = cfs_rq; |
7647 | se->load.weight = tg->shares; |
7648 | se->load.inv_weight = 0; |
7649 | se->parent = parent; |
7650 | } |
7651 | #endif |
7652 | |
7653 | #ifdef CONFIG_RT_GROUP_SCHED |
7654 | static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq, |
7655 | struct sched_rt_entity *rt_se, int cpu, int add, |
7656 | struct sched_rt_entity *parent) |
7657 | { |
7658 | struct rq *rq = cpu_rq(cpu); |
7659 | |
7660 | tg->rt_rq[cpu] = rt_rq; |
7661 | init_rt_rq(rt_rq, rq); |
7662 | rt_rq->tg = tg; |
7663 | rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime; |
7664 | if (add) |
7665 | list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list); |
7666 | |
7667 | tg->rt_se[cpu] = rt_se; |
7668 | if (!rt_se) |
7669 | return; |
7670 | |
7671 | if (!parent) |
7672 | rt_se->rt_rq = &rq->rt; |
7673 | else |
7674 | rt_se->rt_rq = parent->my_q; |
7675 | |
7676 | rt_se->my_q = rt_rq; |
7677 | rt_se->parent = parent; |
7678 | INIT_LIST_HEAD(&rt_se->run_list); |
7679 | } |
7680 | #endif |
7681 | |
7682 | void __init sched_init(void) |
7683 | { |
7684 | int i, j; |
7685 | unsigned long alloc_size = 0, ptr; |
7686 | |
7687 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7688 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); |
7689 | #endif |
7690 | #ifdef CONFIG_RT_GROUP_SCHED |
7691 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); |
7692 | #endif |
7693 | #ifdef CONFIG_CPUMASK_OFFSTACK |
7694 | alloc_size += num_possible_cpus() * cpumask_size(); |
7695 | #endif |
7696 | if (alloc_size) { |
7697 | ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); |
7698 | |
7699 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7700 | init_task_group.se = (struct sched_entity **)ptr; |
7701 | ptr += nr_cpu_ids * sizeof(void **); |
7702 | |
7703 | init_task_group.cfs_rq = (struct cfs_rq **)ptr; |
7704 | ptr += nr_cpu_ids * sizeof(void **); |
7705 | |
7706 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
7707 | #ifdef CONFIG_RT_GROUP_SCHED |
7708 | init_task_group.rt_se = (struct sched_rt_entity **)ptr; |
7709 | ptr += nr_cpu_ids * sizeof(void **); |
7710 | |
7711 | init_task_group.rt_rq = (struct rt_rq **)ptr; |
7712 | ptr += nr_cpu_ids * sizeof(void **); |
7713 | |
7714 | #endif /* CONFIG_RT_GROUP_SCHED */ |
7715 | #ifdef CONFIG_CPUMASK_OFFSTACK |
7716 | for_each_possible_cpu(i) { |
7717 | per_cpu(load_balance_tmpmask, i) = (void *)ptr; |
7718 | ptr += cpumask_size(); |
7719 | } |
7720 | #endif /* CONFIG_CPUMASK_OFFSTACK */ |
7721 | } |
7722 | |
7723 | #ifdef CONFIG_SMP |
7724 | init_defrootdomain(); |
7725 | #endif |
7726 | |
7727 | init_rt_bandwidth(&def_rt_bandwidth, |
7728 | global_rt_period(), global_rt_runtime()); |
7729 | |
7730 | #ifdef CONFIG_RT_GROUP_SCHED |
7731 | init_rt_bandwidth(&init_task_group.rt_bandwidth, |
7732 | global_rt_period(), global_rt_runtime()); |
7733 | #endif /* CONFIG_RT_GROUP_SCHED */ |
7734 | |
7735 | #ifdef CONFIG_CGROUP_SCHED |
7736 | list_add(&init_task_group.list, &task_groups); |
7737 | INIT_LIST_HEAD(&init_task_group.children); |
7738 | |
7739 | #endif /* CONFIG_CGROUP_SCHED */ |
7740 | |
7741 | #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP |
7742 | update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long), |
7743 | __alignof__(unsigned long)); |
7744 | #endif |
7745 | for_each_possible_cpu(i) { |
7746 | struct rq *rq; |
7747 | |
7748 | rq = cpu_rq(i); |
7749 | raw_spin_lock_init(&rq->lock); |
7750 | rq->nr_running = 0; |
7751 | rq->calc_load_active = 0; |
7752 | rq->calc_load_update = jiffies + LOAD_FREQ; |
7753 | init_cfs_rq(&rq->cfs, rq); |
7754 | init_rt_rq(&rq->rt, rq); |
7755 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7756 | init_task_group.shares = init_task_group_load; |
7757 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); |
7758 | #ifdef CONFIG_CGROUP_SCHED |
7759 | /* |
7760 | * How much cpu bandwidth does init_task_group get? |
7761 | * |
7762 | * In case of task-groups formed thr' the cgroup filesystem, it |
7763 | * gets 100% of the cpu resources in the system. This overall |
7764 | * system cpu resource is divided among the tasks of |
7765 | * init_task_group and its child task-groups in a fair manner, |
7766 | * based on each entity's (task or task-group's) weight |
7767 | * (se->load.weight). |
7768 | * |
7769 | * In other words, if init_task_group has 10 tasks of weight |
7770 | * 1024) and two child groups A0 and A1 (of weight 1024 each), |
7771 | * then A0's share of the cpu resource is: |
7772 | * |
7773 | * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% |
7774 | * |
7775 | * We achieve this by letting init_task_group's tasks sit |
7776 | * directly in rq->cfs (i.e init_task_group->se[] = NULL). |
7777 | */ |
7778 | init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL); |
7779 | #endif |
7780 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
7781 | |
7782 | rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; |
7783 | #ifdef CONFIG_RT_GROUP_SCHED |
7784 | INIT_LIST_HEAD(&rq->leaf_rt_rq_list); |
7785 | #ifdef CONFIG_CGROUP_SCHED |
7786 | init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL); |
7787 | #endif |
7788 | #endif |
7789 | |
7790 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
7791 | rq->cpu_load[j] = 0; |
7792 | #ifdef CONFIG_SMP |
7793 | rq->sd = NULL; |
7794 | rq->rd = NULL; |
7795 | rq->post_schedule = 0; |
7796 | rq->active_balance = 0; |
7797 | rq->next_balance = jiffies; |
7798 | rq->push_cpu = 0; |
7799 | rq->cpu = i; |
7800 | rq->online = 0; |
7801 | rq->migration_thread = NULL; |
7802 | rq->idle_stamp = 0; |
7803 | rq->avg_idle = 2*sysctl_sched_migration_cost; |
7804 | INIT_LIST_HEAD(&rq->migration_queue); |
7805 | rq_attach_root(rq, &def_root_domain); |
7806 | #endif |
7807 | init_rq_hrtick(rq); |
7808 | atomic_set(&rq->nr_iowait, 0); |
7809 | } |
7810 | |
7811 | set_load_weight(&init_task); |
7812 | |
7813 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
7814 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); |
7815 | #endif |
7816 | |
7817 | #ifdef CONFIG_SMP |
7818 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); |
7819 | #endif |
7820 | |
7821 | #ifdef CONFIG_RT_MUTEXES |
7822 | plist_head_init_raw(&init_task.pi_waiters, &init_task.pi_lock); |
7823 | #endif |
7824 | |
7825 | /* |
7826 | * The boot idle thread does lazy MMU switching as well: |
7827 | */ |
7828 | atomic_inc(&init_mm.mm_count); |
7829 | enter_lazy_tlb(&init_mm, current); |
7830 | |
7831 | /* |
7832 | * Make us the idle thread. Technically, schedule() should not be |
7833 | * called from this thread, however somewhere below it might be, |
7834 | * but because we are the idle thread, we just pick up running again |
7835 | * when this runqueue becomes "idle". |
7836 | */ |
7837 | init_idle(current, smp_processor_id()); |
7838 | |
7839 | calc_load_update = jiffies + LOAD_FREQ; |
7840 | |
7841 | /* |
7842 | * During early bootup we pretend to be a normal task: |
7843 | */ |
7844 | current->sched_class = &fair_sched_class; |
7845 | |
7846 | /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */ |
7847 | zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT); |
7848 | #ifdef CONFIG_SMP |
7849 | #ifdef CONFIG_NO_HZ |
7850 | zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT); |
7851 | alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT); |
7852 | #endif |
7853 | /* May be allocated at isolcpus cmdline parse time */ |
7854 | if (cpu_isolated_map == NULL) |
7855 | zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); |
7856 | #endif /* SMP */ |
7857 | |
7858 | perf_event_init(); |
7859 | |
7860 | scheduler_running = 1; |
7861 | } |
7862 | |
7863 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
7864 | static inline int preempt_count_equals(int preempt_offset) |
7865 | { |
7866 | int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); |
7867 | |
7868 | return (nested == PREEMPT_INATOMIC_BASE + preempt_offset); |
7869 | } |
7870 | |
7871 | void __might_sleep(const char *file, int line, int preempt_offset) |
7872 | { |
7873 | #ifdef in_atomic |
7874 | static unsigned long prev_jiffy; /* ratelimiting */ |
7875 | |
7876 | if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || |
7877 | system_state != SYSTEM_RUNNING || oops_in_progress) |
7878 | return; |
7879 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) |
7880 | return; |
7881 | prev_jiffy = jiffies; |
7882 | |
7883 | printk(KERN_ERR |
7884 | "BUG: sleeping function called from invalid context at %s:%d\n", |
7885 | file, line); |
7886 | printk(KERN_ERR |
7887 | "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", |
7888 | in_atomic(), irqs_disabled(), |
7889 | current->pid, current->comm); |
7890 | |
7891 | debug_show_held_locks(current); |
7892 | if (irqs_disabled()) |
7893 | print_irqtrace_events(current); |
7894 | dump_stack(); |
7895 | #endif |
7896 | } |
7897 | EXPORT_SYMBOL(__might_sleep); |
7898 | #endif |
7899 | |
7900 | #ifdef CONFIG_MAGIC_SYSRQ |
7901 | static void normalize_task(struct rq *rq, struct task_struct *p) |
7902 | { |
7903 | int on_rq; |
7904 | |
7905 | update_rq_clock(rq); |
7906 | on_rq = p->se.on_rq; |
7907 | if (on_rq) |
7908 | deactivate_task(rq, p, 0); |
7909 | __setscheduler(rq, p, SCHED_NORMAL, 0); |
7910 | if (on_rq) { |
7911 | activate_task(rq, p, 0); |
7912 | resched_task(rq->curr); |
7913 | } |
7914 | } |
7915 | |
7916 | void normalize_rt_tasks(void) |
7917 | { |
7918 | struct task_struct *g, *p; |
7919 | unsigned long flags; |
7920 | struct rq *rq; |
7921 | |
7922 | read_lock_irqsave(&tasklist_lock, flags); |
7923 | do_each_thread(g, p) { |
7924 | /* |
7925 | * Only normalize user tasks: |
7926 | */ |
7927 | if (!p->mm) |
7928 | continue; |
7929 | |
7930 | p->se.exec_start = 0; |
7931 | #ifdef CONFIG_SCHEDSTATS |
7932 | p->se.wait_start = 0; |
7933 | p->se.sleep_start = 0; |
7934 | p->se.block_start = 0; |
7935 | #endif |
7936 | |
7937 | if (!rt_task(p)) { |
7938 | /* |
7939 | * Renice negative nice level userspace |
7940 | * tasks back to 0: |
7941 | */ |
7942 | if (TASK_NICE(p) < 0 && p->mm) |
7943 | set_user_nice(p, 0); |
7944 | continue; |
7945 | } |
7946 | |
7947 | raw_spin_lock(&p->pi_lock); |
7948 | rq = __task_rq_lock(p); |
7949 | |
7950 | normalize_task(rq, p); |
7951 | |
7952 | __task_rq_unlock(rq); |
7953 | raw_spin_unlock(&p->pi_lock); |
7954 | } while_each_thread(g, p); |
7955 | |
7956 | read_unlock_irqrestore(&tasklist_lock, flags); |
7957 | } |
7958 | |
7959 | #endif /* CONFIG_MAGIC_SYSRQ */ |
7960 | |
7961 | #ifdef CONFIG_IA64 |
7962 | /* |
7963 | * These functions are only useful for the IA64 MCA handling. |
7964 | * |
7965 | * They can only be called when the whole system has been |
7966 | * stopped - every CPU needs to be quiescent, and no scheduling |
7967 | * activity can take place. Using them for anything else would |
7968 | * be a serious bug, and as a result, they aren't even visible |
7969 | * under any other configuration. |
7970 | */ |
7971 | |
7972 | /** |
7973 | * curr_task - return the current task for a given cpu. |
7974 | * @cpu: the processor in question. |
7975 | * |
7976 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
7977 | */ |
7978 | struct task_struct *curr_task(int cpu) |
7979 | { |
7980 | return cpu_curr(cpu); |
7981 | } |
7982 | |
7983 | /** |
7984 | * set_curr_task - set the current task for a given cpu. |
7985 | * @cpu: the processor in question. |
7986 | * @p: the task pointer to set. |
7987 | * |
7988 | * Description: This function must only be used when non-maskable interrupts |
7989 | * are serviced on a separate stack. It allows the architecture to switch the |
7990 | * notion of the current task on a cpu in a non-blocking manner. This function |
7991 | * must be called with all CPU's synchronized, and interrupts disabled, the |
7992 | * and caller must save the original value of the current task (see |
7993 | * curr_task() above) and restore that value before reenabling interrupts and |
7994 | * re-starting the system. |
7995 | * |
7996 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
7997 | */ |
7998 | void set_curr_task(int cpu, struct task_struct *p) |
7999 | { |
8000 | cpu_curr(cpu) = p; |
8001 | } |
8002 | |
8003 | #endif |
8004 | |
8005 | #ifdef CONFIG_FAIR_GROUP_SCHED |
8006 | static void free_fair_sched_group(struct task_group *tg) |
8007 | { |
8008 | int i; |
8009 | |
8010 | for_each_possible_cpu(i) { |
8011 | if (tg->cfs_rq) |
8012 | kfree(tg->cfs_rq[i]); |
8013 | if (tg->se) |
8014 | kfree(tg->se[i]); |
8015 | } |
8016 | |
8017 | kfree(tg->cfs_rq); |
8018 | kfree(tg->se); |
8019 | } |
8020 | |
8021 | static |
8022 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) |
8023 | { |
8024 | struct cfs_rq *cfs_rq; |
8025 | struct sched_entity *se; |
8026 | struct rq *rq; |
8027 | int i; |
8028 | |
8029 | tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL); |
8030 | if (!tg->cfs_rq) |
8031 | goto err; |
8032 | tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL); |
8033 | if (!tg->se) |
8034 | goto err; |
8035 | |
8036 | tg->shares = NICE_0_LOAD; |
8037 | |
8038 | for_each_possible_cpu(i) { |
8039 | rq = cpu_rq(i); |
8040 | |
8041 | cfs_rq = kzalloc_node(sizeof(struct cfs_rq), |
8042 | GFP_KERNEL, cpu_to_node(i)); |
8043 | if (!cfs_rq) |
8044 | goto err; |
8045 | |
8046 | se = kzalloc_node(sizeof(struct sched_entity), |
8047 | GFP_KERNEL, cpu_to_node(i)); |
8048 | if (!se) |
8049 | goto err_free_rq; |
8050 | |
8051 | init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]); |
8052 | } |
8053 | |
8054 | return 1; |
8055 | |
8056 | err_free_rq: |
8057 | kfree(cfs_rq); |
8058 | err: |
8059 | return 0; |
8060 | } |
8061 | |
8062 | static inline void register_fair_sched_group(struct task_group *tg, int cpu) |
8063 | { |
8064 | list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list, |
8065 | &cpu_rq(cpu)->leaf_cfs_rq_list); |
8066 | } |
8067 | |
8068 | static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) |
8069 | { |
8070 | list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list); |
8071 | } |
8072 | #else /* !CONFG_FAIR_GROUP_SCHED */ |
8073 | static inline void free_fair_sched_group(struct task_group *tg) |
8074 | { |
8075 | } |
8076 | |
8077 | static inline |
8078 | int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) |
8079 | { |
8080 | return 1; |
8081 | } |
8082 | |
8083 | static inline void register_fair_sched_group(struct task_group *tg, int cpu) |
8084 | { |
8085 | } |
8086 | |
8087 | static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) |
8088 | { |
8089 | } |
8090 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
8091 | |
8092 | #ifdef CONFIG_RT_GROUP_SCHED |
8093 | static void free_rt_sched_group(struct task_group *tg) |
8094 | { |
8095 | int i; |
8096 | |
8097 | destroy_rt_bandwidth(&tg->rt_bandwidth); |
8098 | |
8099 | for_each_possible_cpu(i) { |
8100 | if (tg->rt_rq) |
8101 | kfree(tg->rt_rq[i]); |
8102 | if (tg->rt_se) |
8103 | kfree(tg->rt_se[i]); |
8104 | } |
8105 | |
8106 | kfree(tg->rt_rq); |
8107 | kfree(tg->rt_se); |
8108 | } |
8109 | |
8110 | static |
8111 | int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) |
8112 | { |
8113 | struct rt_rq *rt_rq; |
8114 | struct sched_rt_entity *rt_se; |
8115 | struct rq *rq; |
8116 | int i; |
8117 | |
8118 | tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL); |
8119 | if (!tg->rt_rq) |
8120 | goto err; |
8121 | tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL); |
8122 | if (!tg->rt_se) |
8123 | goto err; |
8124 | |
8125 | init_rt_bandwidth(&tg->rt_bandwidth, |
8126 | ktime_to_ns(def_rt_bandwidth.rt_period), 0); |
8127 | |
8128 | for_each_possible_cpu(i) { |
8129 | rq = cpu_rq(i); |
8130 | |
8131 | rt_rq = kzalloc_node(sizeof(struct rt_rq), |
8132 | GFP_KERNEL, cpu_to_node(i)); |
8133 | if (!rt_rq) |
8134 | goto err; |
8135 | |
8136 | rt_se = kzalloc_node(sizeof(struct sched_rt_entity), |
8137 | GFP_KERNEL, cpu_to_node(i)); |
8138 | if (!rt_se) |
8139 | goto err_free_rq; |
8140 | |
8141 | init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]); |
8142 | } |
8143 | |
8144 | return 1; |
8145 | |
8146 | err_free_rq: |
8147 | kfree(rt_rq); |
8148 | err: |
8149 | return 0; |
8150 | } |
8151 | |
8152 | static inline void register_rt_sched_group(struct task_group *tg, int cpu) |
8153 | { |
8154 | list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list, |
8155 | &cpu_rq(cpu)->leaf_rt_rq_list); |
8156 | } |
8157 | |
8158 | static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) |
8159 | { |
8160 | list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list); |
8161 | } |
8162 | #else /* !CONFIG_RT_GROUP_SCHED */ |
8163 | static inline void free_rt_sched_group(struct task_group *tg) |
8164 | { |
8165 | } |
8166 | |
8167 | static inline |
8168 | int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) |
8169 | { |
8170 | return 1; |
8171 | } |
8172 | |
8173 | static inline void register_rt_sched_group(struct task_group *tg, int cpu) |
8174 | { |
8175 | } |
8176 | |
8177 | static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) |
8178 | { |
8179 | } |
8180 | #endif /* CONFIG_RT_GROUP_SCHED */ |
8181 | |
8182 | #ifdef CONFIG_CGROUP_SCHED |
8183 | static void free_sched_group(struct task_group *tg) |
8184 | { |
8185 | free_fair_sched_group(tg); |
8186 | free_rt_sched_group(tg); |
8187 | kfree(tg); |
8188 | } |
8189 | |
8190 | /* allocate runqueue etc for a new task group */ |
8191 | struct task_group *sched_create_group(struct task_group *parent) |
8192 | { |
8193 | struct task_group *tg; |
8194 | unsigned long flags; |
8195 | int i; |
8196 | |
8197 | tg = kzalloc(sizeof(*tg), GFP_KERNEL); |
8198 | if (!tg) |
8199 | return ERR_PTR(-ENOMEM); |
8200 | |
8201 | if (!alloc_fair_sched_group(tg, parent)) |
8202 | goto err; |
8203 | |
8204 | if (!alloc_rt_sched_group(tg, parent)) |
8205 | goto err; |
8206 | |
8207 | spin_lock_irqsave(&task_group_lock, flags); |
8208 | for_each_possible_cpu(i) { |
8209 | register_fair_sched_group(tg, i); |
8210 | register_rt_sched_group(tg, i); |
8211 | } |
8212 | list_add_rcu(&tg->list, &task_groups); |
8213 | |
8214 | WARN_ON(!parent); /* root should already exist */ |
8215 | |
8216 | tg->parent = parent; |
8217 | INIT_LIST_HEAD(&tg->children); |
8218 | list_add_rcu(&tg->siblings, &parent->children); |
8219 | spin_unlock_irqrestore(&task_group_lock, flags); |
8220 | |
8221 | return tg; |
8222 | |
8223 | err: |
8224 | free_sched_group(tg); |
8225 | return ERR_PTR(-ENOMEM); |
8226 | } |
8227 | |
8228 | /* rcu callback to free various structures associated with a task group */ |
8229 | static void free_sched_group_rcu(struct rcu_head *rhp) |
8230 | { |
8231 | /* now it should be safe to free those cfs_rqs */ |
8232 | free_sched_group(container_of(rhp, struct task_group, rcu)); |
8233 | } |
8234 | |
8235 | /* Destroy runqueue etc associated with a task group */ |
8236 | void sched_destroy_group(struct task_group *tg) |
8237 | { |
8238 | unsigned long flags; |
8239 | int i; |
8240 | |
8241 | spin_lock_irqsave(&task_group_lock, flags); |
8242 | for_each_possible_cpu(i) { |
8243 | unregister_fair_sched_group(tg, i); |
8244 | unregister_rt_sched_group(tg, i); |
8245 | } |
8246 | list_del_rcu(&tg->list); |
8247 | list_del_rcu(&tg->siblings); |
8248 | spin_unlock_irqrestore(&task_group_lock, flags); |
8249 | |
8250 | /* wait for possible concurrent references to cfs_rqs complete */ |
8251 | call_rcu(&tg->rcu, free_sched_group_rcu); |
8252 | } |
8253 | |
8254 | /* change task's runqueue when it moves between groups. |
8255 | * The caller of this function should have put the task in its new group |
8256 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to |
8257 | * reflect its new group. |
8258 | */ |
8259 | void sched_move_task(struct task_struct *tsk) |
8260 | { |
8261 | int on_rq, running; |
8262 | unsigned long flags; |
8263 | struct rq *rq; |
8264 | |
8265 | rq = task_rq_lock(tsk, &flags); |
8266 | |
8267 | update_rq_clock(rq); |
8268 | |
8269 | running = task_current(rq, tsk); |
8270 | on_rq = tsk->se.on_rq; |
8271 | |
8272 | if (on_rq) |
8273 | dequeue_task(rq, tsk, 0); |
8274 | if (unlikely(running)) |
8275 | tsk->sched_class->put_prev_task(rq, tsk); |
8276 | |
8277 | set_task_rq(tsk, task_cpu(tsk)); |
8278 | |
8279 | #ifdef CONFIG_FAIR_GROUP_SCHED |
8280 | if (tsk->sched_class->moved_group) |
8281 | tsk->sched_class->moved_group(tsk, on_rq); |
8282 | #endif |
8283 | |
8284 | if (unlikely(running)) |
8285 | tsk->sched_class->set_curr_task(rq); |
8286 | if (on_rq) |
8287 | enqueue_task(rq, tsk, 0, false); |
8288 | |
8289 | task_rq_unlock(rq, &flags); |
8290 | } |
8291 | #endif /* CONFIG_CGROUP_SCHED */ |
8292 | |
8293 | #ifdef CONFIG_FAIR_GROUP_SCHED |
8294 | static void __set_se_shares(struct sched_entity *se, unsigned long shares) |
8295 | { |
8296 | struct cfs_rq *cfs_rq = se->cfs_rq; |
8297 | int on_rq; |
8298 | |
8299 | on_rq = se->on_rq; |
8300 | if (on_rq) |
8301 | dequeue_entity(cfs_rq, se, 0); |
8302 | |
8303 | se->load.weight = shares; |
8304 | se->load.inv_weight = 0; |
8305 | |
8306 | if (on_rq) |
8307 | enqueue_entity(cfs_rq, se, 0); |
8308 | } |
8309 | |
8310 | static void set_se_shares(struct sched_entity *se, unsigned long shares) |
8311 | { |
8312 | struct cfs_rq *cfs_rq = se->cfs_rq; |
8313 | struct rq *rq = cfs_rq->rq; |
8314 | unsigned long flags; |
8315 | |
8316 | raw_spin_lock_irqsave(&rq->lock, flags); |
8317 | __set_se_shares(se, shares); |
8318 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
8319 | } |
8320 | |
8321 | static DEFINE_MUTEX(shares_mutex); |
8322 | |
8323 | int sched_group_set_shares(struct task_group *tg, unsigned long shares) |
8324 | { |
8325 | int i; |
8326 | unsigned long flags; |
8327 | |
8328 | /* |
8329 | * We can't change the weight of the root cgroup. |
8330 | */ |
8331 | if (!tg->se[0]) |
8332 | return -EINVAL; |
8333 | |
8334 | if (shares < MIN_SHARES) |
8335 | shares = MIN_SHARES; |
8336 | else if (shares > MAX_SHARES) |
8337 | shares = MAX_SHARES; |
8338 | |
8339 | mutex_lock(&shares_mutex); |
8340 | if (tg->shares == shares) |
8341 | goto done; |
8342 | |
8343 | spin_lock_irqsave(&task_group_lock, flags); |
8344 | for_each_possible_cpu(i) |
8345 | unregister_fair_sched_group(tg, i); |
8346 | list_del_rcu(&tg->siblings); |
8347 | spin_unlock_irqrestore(&task_group_lock, flags); |
8348 | |
8349 | /* wait for any ongoing reference to this group to finish */ |
8350 | synchronize_sched(); |
8351 | |
8352 | /* |
8353 | * Now we are free to modify the group's share on each cpu |
8354 | * w/o tripping rebalance_share or load_balance_fair. |
8355 | */ |
8356 | tg->shares = shares; |
8357 | for_each_possible_cpu(i) { |
8358 | /* |
8359 | * force a rebalance |
8360 | */ |
8361 | cfs_rq_set_shares(tg->cfs_rq[i], 0); |
8362 | set_se_shares(tg->se[i], shares); |
8363 | } |
8364 | |
8365 | /* |
8366 | * Enable load balance activity on this group, by inserting it back on |
8367 | * each cpu's rq->leaf_cfs_rq_list. |
8368 | */ |
8369 | spin_lock_irqsave(&task_group_lock, flags); |
8370 | for_each_possible_cpu(i) |
8371 | register_fair_sched_group(tg, i); |
8372 | list_add_rcu(&tg->siblings, &tg->parent->children); |
8373 | spin_unlock_irqrestore(&task_group_lock, flags); |
8374 | done: |
8375 | mutex_unlock(&shares_mutex); |
8376 | return 0; |
8377 | } |
8378 | |
8379 | unsigned long sched_group_shares(struct task_group *tg) |
8380 | { |
8381 | return tg->shares; |
8382 | } |
8383 | #endif |
8384 | |
8385 | #ifdef CONFIG_RT_GROUP_SCHED |
8386 | /* |
8387 | * Ensure that the real time constraints are schedulable. |
8388 | */ |
8389 | static DEFINE_MUTEX(rt_constraints_mutex); |
8390 | |
8391 | static unsigned long to_ratio(u64 period, u64 runtime) |
8392 | { |
8393 | if (runtime == RUNTIME_INF) |
8394 | return 1ULL << 20; |
8395 | |
8396 | return div64_u64(runtime << 20, period); |
8397 | } |
8398 | |
8399 | /* Must be called with tasklist_lock held */ |
8400 | static inline int tg_has_rt_tasks(struct task_group *tg) |
8401 | { |
8402 | struct task_struct *g, *p; |
8403 | |
8404 | do_each_thread(g, p) { |
8405 | if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg) |
8406 | return 1; |
8407 | } while_each_thread(g, p); |
8408 | |
8409 | return 0; |
8410 | } |
8411 | |
8412 | struct rt_schedulable_data { |
8413 | struct task_group *tg; |
8414 | u64 rt_period; |
8415 | u64 rt_runtime; |
8416 | }; |
8417 | |
8418 | static int tg_schedulable(struct task_group *tg, void *data) |
8419 | { |
8420 | struct rt_schedulable_data *d = data; |
8421 | struct task_group *child; |
8422 | unsigned long total, sum = 0; |
8423 | u64 period, runtime; |
8424 | |
8425 | period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
8426 | runtime = tg->rt_bandwidth.rt_runtime; |
8427 | |
8428 | if (tg == d->tg) { |
8429 | period = d->rt_period; |
8430 | runtime = d->rt_runtime; |
8431 | } |
8432 | |
8433 | /* |
8434 | * Cannot have more runtime than the period. |
8435 | */ |
8436 | if (runtime > period && runtime != RUNTIME_INF) |
8437 | return -EINVAL; |
8438 | |
8439 | /* |
8440 | * Ensure we don't starve existing RT tasks. |
8441 | */ |
8442 | if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) |
8443 | return -EBUSY; |
8444 | |
8445 | total = to_ratio(period, runtime); |
8446 | |
8447 | /* |
8448 | * Nobody can have more than the global setting allows. |
8449 | */ |
8450 | if (total > to_ratio(global_rt_period(), global_rt_runtime())) |
8451 | return -EINVAL; |
8452 | |
8453 | /* |
8454 | * The sum of our children's runtime should not exceed our own. |
8455 | */ |
8456 | list_for_each_entry_rcu(child, &tg->children, siblings) { |
8457 | period = ktime_to_ns(child->rt_bandwidth.rt_period); |
8458 | runtime = child->rt_bandwidth.rt_runtime; |
8459 | |
8460 | if (child == d->tg) { |
8461 | period = d->rt_period; |
8462 | runtime = d->rt_runtime; |
8463 | } |
8464 | |
8465 | sum += to_ratio(period, runtime); |
8466 | } |
8467 | |
8468 | if (sum > total) |
8469 | return -EINVAL; |
8470 | |
8471 | return 0; |
8472 | } |
8473 | |
8474 | static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) |
8475 | { |
8476 | struct rt_schedulable_data data = { |
8477 | .tg = tg, |
8478 | .rt_period = period, |
8479 | .rt_runtime = runtime, |
8480 | }; |
8481 | |
8482 | return walk_tg_tree(tg_schedulable, tg_nop, &data); |
8483 | } |
8484 | |
8485 | static int tg_set_bandwidth(struct task_group *tg, |
8486 | u64 rt_period, u64 rt_runtime) |
8487 | { |
8488 | int i, err = 0; |
8489 | |
8490 | mutex_lock(&rt_constraints_mutex); |
8491 | read_lock(&tasklist_lock); |
8492 | err = __rt_schedulable(tg, rt_period, rt_runtime); |
8493 | if (err) |
8494 | goto unlock; |
8495 | |
8496 | raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
8497 | tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); |
8498 | tg->rt_bandwidth.rt_runtime = rt_runtime; |
8499 | |
8500 | for_each_possible_cpu(i) { |
8501 | struct rt_rq *rt_rq = tg->rt_rq[i]; |
8502 | |
8503 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
8504 | rt_rq->rt_runtime = rt_runtime; |
8505 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
8506 | } |
8507 | raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
8508 | unlock: |
8509 | read_unlock(&tasklist_lock); |
8510 | mutex_unlock(&rt_constraints_mutex); |
8511 | |
8512 | return err; |
8513 | } |
8514 | |
8515 | int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) |
8516 | { |
8517 | u64 rt_runtime, rt_period; |
8518 | |
8519 | rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
8520 | rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; |
8521 | if (rt_runtime_us < 0) |
8522 | rt_runtime = RUNTIME_INF; |
8523 | |
8524 | return tg_set_bandwidth(tg, rt_period, rt_runtime); |
8525 | } |
8526 | |
8527 | long sched_group_rt_runtime(struct task_group *tg) |
8528 | { |
8529 | u64 rt_runtime_us; |
8530 | |
8531 | if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) |
8532 | return -1; |
8533 | |
8534 | rt_runtime_us = tg->rt_bandwidth.rt_runtime; |
8535 | do_div(rt_runtime_us, NSEC_PER_USEC); |
8536 | return rt_runtime_us; |
8537 | } |
8538 | |
8539 | int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) |
8540 | { |
8541 | u64 rt_runtime, rt_period; |
8542 | |
8543 | rt_period = (u64)rt_period_us * NSEC_PER_USEC; |
8544 | rt_runtime = tg->rt_bandwidth.rt_runtime; |
8545 | |
8546 | if (rt_period == 0) |
8547 | return -EINVAL; |
8548 | |
8549 | return tg_set_bandwidth(tg, rt_period, rt_runtime); |
8550 | } |
8551 | |
8552 | long sched_group_rt_period(struct task_group *tg) |
8553 | { |
8554 | u64 rt_period_us; |
8555 | |
8556 | rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); |
8557 | do_div(rt_period_us, NSEC_PER_USEC); |
8558 | return rt_period_us; |
8559 | } |
8560 | |
8561 | static int sched_rt_global_constraints(void) |
8562 | { |
8563 | u64 runtime, period; |
8564 | int ret = 0; |
8565 | |
8566 | if (sysctl_sched_rt_period <= 0) |
8567 | return -EINVAL; |
8568 | |
8569 | runtime = global_rt_runtime(); |
8570 | period = global_rt_period(); |
8571 | |
8572 | /* |
8573 | * Sanity check on the sysctl variables. |
8574 | */ |
8575 | if (runtime > period && runtime != RUNTIME_INF) |
8576 | return -EINVAL; |
8577 | |
8578 | mutex_lock(&rt_constraints_mutex); |
8579 | read_lock(&tasklist_lock); |
8580 | ret = __rt_schedulable(NULL, 0, 0); |
8581 | read_unlock(&tasklist_lock); |
8582 | mutex_unlock(&rt_constraints_mutex); |
8583 | |
8584 | return ret; |
8585 | } |
8586 | |
8587 | int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) |
8588 | { |
8589 | /* Don't accept realtime tasks when there is no way for them to run */ |
8590 | if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) |
8591 | return 0; |
8592 | |
8593 | return 1; |
8594 | } |
8595 | |
8596 | #else /* !CONFIG_RT_GROUP_SCHED */ |
8597 | static int sched_rt_global_constraints(void) |
8598 | { |
8599 | unsigned long flags; |
8600 | int i; |
8601 | |
8602 | if (sysctl_sched_rt_period <= 0) |
8603 | return -EINVAL; |
8604 | |
8605 | /* |
8606 | * There's always some RT tasks in the root group |
8607 | * -- migration, kstopmachine etc.. |
8608 | */ |
8609 | if (sysctl_sched_rt_runtime == 0) |
8610 | return -EBUSY; |
8611 | |
8612 | raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); |
8613 | for_each_possible_cpu(i) { |
8614 | struct rt_rq *rt_rq = &cpu_rq(i)->rt; |
8615 | |
8616 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
8617 | rt_rq->rt_runtime = global_rt_runtime(); |
8618 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
8619 | } |
8620 | raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); |
8621 | |
8622 | return 0; |
8623 | } |
8624 | #endif /* CONFIG_RT_GROUP_SCHED */ |
8625 | |
8626 | int sched_rt_handler(struct ctl_table *table, int write, |
8627 | void __user *buffer, size_t *lenp, |
8628 | loff_t *ppos) |
8629 | { |
8630 | int ret; |
8631 | int old_period, old_runtime; |
8632 | static DEFINE_MUTEX(mutex); |
8633 | |
8634 | mutex_lock(&mutex); |
8635 | old_period = sysctl_sched_rt_period; |
8636 | old_runtime = sysctl_sched_rt_runtime; |
8637 | |
8638 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
8639 | |
8640 | if (!ret && write) { |
8641 | ret = sched_rt_global_constraints(); |
8642 | if (ret) { |
8643 | sysctl_sched_rt_period = old_period; |
8644 | sysctl_sched_rt_runtime = old_runtime; |
8645 | } else { |
8646 | def_rt_bandwidth.rt_runtime = global_rt_runtime(); |
8647 | def_rt_bandwidth.rt_period = |
8648 | ns_to_ktime(global_rt_period()); |
8649 | } |
8650 | } |
8651 | mutex_unlock(&mutex); |
8652 | |
8653 | return ret; |
8654 | } |
8655 | |
8656 | #ifdef CONFIG_CGROUP_SCHED |
8657 | |
8658 | /* return corresponding task_group object of a cgroup */ |
8659 | static inline struct task_group *cgroup_tg(struct cgroup *cgrp) |
8660 | { |
8661 | return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), |
8662 | struct task_group, css); |
8663 | } |
8664 | |
8665 | static struct cgroup_subsys_state * |
8666 | cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp) |
8667 | { |
8668 | struct task_group *tg, *parent; |
8669 | |
8670 | if (!cgrp->parent) { |
8671 | /* This is early initialization for the top cgroup */ |
8672 | return &init_task_group.css; |
8673 | } |
8674 | |
8675 | parent = cgroup_tg(cgrp->parent); |
8676 | tg = sched_create_group(parent); |
8677 | if (IS_ERR(tg)) |
8678 | return ERR_PTR(-ENOMEM); |
8679 | |
8680 | return &tg->css; |
8681 | } |
8682 | |
8683 | static void |
8684 | cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) |
8685 | { |
8686 | struct task_group *tg = cgroup_tg(cgrp); |
8687 | |
8688 | sched_destroy_group(tg); |
8689 | } |
8690 | |
8691 | static int |
8692 | cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk) |
8693 | { |
8694 | #ifdef CONFIG_RT_GROUP_SCHED |
8695 | if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk)) |
8696 | return -EINVAL; |
8697 | #else |
8698 | /* We don't support RT-tasks being in separate groups */ |
8699 | if (tsk->sched_class != &fair_sched_class) |
8700 | return -EINVAL; |
8701 | #endif |
8702 | return 0; |
8703 | } |
8704 | |
8705 | static int |
8706 | cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
8707 | struct task_struct *tsk, bool threadgroup) |
8708 | { |
8709 | int retval = cpu_cgroup_can_attach_task(cgrp, tsk); |
8710 | if (retval) |
8711 | return retval; |
8712 | if (threadgroup) { |
8713 | struct task_struct *c; |
8714 | rcu_read_lock(); |
8715 | list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) { |
8716 | retval = cpu_cgroup_can_attach_task(cgrp, c); |
8717 | if (retval) { |
8718 | rcu_read_unlock(); |
8719 | return retval; |
8720 | } |
8721 | } |
8722 | rcu_read_unlock(); |
8723 | } |
8724 | return 0; |
8725 | } |
8726 | |
8727 | static void |
8728 | cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
8729 | struct cgroup *old_cont, struct task_struct *tsk, |
8730 | bool threadgroup) |
8731 | { |
8732 | sched_move_task(tsk); |
8733 | if (threadgroup) { |
8734 | struct task_struct *c; |
8735 | rcu_read_lock(); |
8736 | list_for_each_entry_rcu(c, &tsk->thread_group, thread_group) { |
8737 | sched_move_task(c); |
8738 | } |
8739 | rcu_read_unlock(); |
8740 | } |
8741 | } |
8742 | |
8743 | #ifdef CONFIG_FAIR_GROUP_SCHED |
8744 | static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype, |
8745 | u64 shareval) |
8746 | { |
8747 | return sched_group_set_shares(cgroup_tg(cgrp), shareval); |
8748 | } |
8749 | |
8750 | static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) |
8751 | { |
8752 | struct task_group *tg = cgroup_tg(cgrp); |
8753 | |
8754 | return (u64) tg->shares; |
8755 | } |
8756 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
8757 | |
8758 | #ifdef CONFIG_RT_GROUP_SCHED |
8759 | static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, |
8760 | s64 val) |
8761 | { |
8762 | return sched_group_set_rt_runtime(cgroup_tg(cgrp), val); |
8763 | } |
8764 | |
8765 | static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft) |
8766 | { |
8767 | return sched_group_rt_runtime(cgroup_tg(cgrp)); |
8768 | } |
8769 | |
8770 | static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype, |
8771 | u64 rt_period_us) |
8772 | { |
8773 | return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us); |
8774 | } |
8775 | |
8776 | static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) |
8777 | { |
8778 | return sched_group_rt_period(cgroup_tg(cgrp)); |
8779 | } |
8780 | #endif /* CONFIG_RT_GROUP_SCHED */ |
8781 | |
8782 | static struct cftype cpu_files[] = { |
8783 | #ifdef CONFIG_FAIR_GROUP_SCHED |
8784 | { |
8785 | .name = "shares", |
8786 | .read_u64 = cpu_shares_read_u64, |
8787 | .write_u64 = cpu_shares_write_u64, |
8788 | }, |
8789 | #endif |
8790 | #ifdef CONFIG_RT_GROUP_SCHED |
8791 | { |
8792 | .name = "rt_runtime_us", |
8793 | .read_s64 = cpu_rt_runtime_read, |
8794 | .write_s64 = cpu_rt_runtime_write, |
8795 | }, |
8796 | { |
8797 | .name = "rt_period_us", |
8798 | .read_u64 = cpu_rt_period_read_uint, |
8799 | .write_u64 = cpu_rt_period_write_uint, |
8800 | }, |
8801 | #endif |
8802 | }; |
8803 | |
8804 | static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) |
8805 | { |
8806 | return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); |
8807 | } |
8808 | |
8809 | struct cgroup_subsys cpu_cgroup_subsys = { |
8810 | .name = "cpu", |
8811 | .create = cpu_cgroup_create, |
8812 | .destroy = cpu_cgroup_destroy, |
8813 | .can_attach = cpu_cgroup_can_attach, |
8814 | .attach = cpu_cgroup_attach, |
8815 | .populate = cpu_cgroup_populate, |
8816 | .subsys_id = cpu_cgroup_subsys_id, |
8817 | .early_init = 1, |
8818 | }; |
8819 | |
8820 | #endif /* CONFIG_CGROUP_SCHED */ |
8821 | |
8822 | #ifdef CONFIG_CGROUP_CPUACCT |
8823 | |
8824 | /* |
8825 | * CPU accounting code for task groups. |
8826 | * |
8827 | * Based on the work by Paul Menage (menage@google.com) and Balbir Singh |
8828 | * (balbir@in.ibm.com). |
8829 | */ |
8830 | |
8831 | /* track cpu usage of a group of tasks and its child groups */ |
8832 | struct cpuacct { |
8833 | struct cgroup_subsys_state css; |
8834 | /* cpuusage holds pointer to a u64-type object on every cpu */ |
8835 | u64 __percpu *cpuusage; |
8836 | struct percpu_counter cpustat[CPUACCT_STAT_NSTATS]; |
8837 | struct cpuacct *parent; |
8838 | }; |
8839 | |
8840 | struct cgroup_subsys cpuacct_subsys; |
8841 | |
8842 | /* return cpu accounting group corresponding to this container */ |
8843 | static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp) |
8844 | { |
8845 | return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id), |
8846 | struct cpuacct, css); |
8847 | } |
8848 | |
8849 | /* return cpu accounting group to which this task belongs */ |
8850 | static inline struct cpuacct *task_ca(struct task_struct *tsk) |
8851 | { |
8852 | return container_of(task_subsys_state(tsk, cpuacct_subsys_id), |
8853 | struct cpuacct, css); |
8854 | } |
8855 | |
8856 | /* create a new cpu accounting group */ |
8857 | static struct cgroup_subsys_state *cpuacct_create( |
8858 | struct cgroup_subsys *ss, struct cgroup *cgrp) |
8859 | { |
8860 | struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL); |
8861 | int i; |
8862 | |
8863 | if (!ca) |
8864 | goto out; |
8865 | |
8866 | ca->cpuusage = alloc_percpu(u64); |
8867 | if (!ca->cpuusage) |
8868 | goto out_free_ca; |
8869 | |
8870 | for (i = 0; i < CPUACCT_STAT_NSTATS; i++) |
8871 | if (percpu_counter_init(&ca->cpustat[i], 0)) |
8872 | goto out_free_counters; |
8873 | |
8874 | if (cgrp->parent) |
8875 | ca->parent = cgroup_ca(cgrp->parent); |
8876 | |
8877 | return &ca->css; |
8878 | |
8879 | out_free_counters: |
8880 | while (--i >= 0) |
8881 | percpu_counter_destroy(&ca->cpustat[i]); |
8882 | free_percpu(ca->cpuusage); |
8883 | out_free_ca: |
8884 | kfree(ca); |
8885 | out: |
8886 | return ERR_PTR(-ENOMEM); |
8887 | } |
8888 | |
8889 | /* destroy an existing cpu accounting group */ |
8890 | static void |
8891 | cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) |
8892 | { |
8893 | struct cpuacct *ca = cgroup_ca(cgrp); |
8894 | int i; |
8895 | |
8896 | for (i = 0; i < CPUACCT_STAT_NSTATS; i++) |
8897 | percpu_counter_destroy(&ca->cpustat[i]); |
8898 | free_percpu(ca->cpuusage); |
8899 | kfree(ca); |
8900 | } |
8901 | |
8902 | static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu) |
8903 | { |
8904 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
8905 | u64 data; |
8906 | |
8907 | #ifndef CONFIG_64BIT |
8908 | /* |
8909 | * Take rq->lock to make 64-bit read safe on 32-bit platforms. |
8910 | */ |
8911 | raw_spin_lock_irq(&cpu_rq(cpu)->lock); |
8912 | data = *cpuusage; |
8913 | raw_spin_unlock_irq(&cpu_rq(cpu)->lock); |
8914 | #else |
8915 | data = *cpuusage; |
8916 | #endif |
8917 | |
8918 | return data; |
8919 | } |
8920 | |
8921 | static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) |
8922 | { |
8923 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
8924 | |
8925 | #ifndef CONFIG_64BIT |
8926 | /* |
8927 | * Take rq->lock to make 64-bit write safe on 32-bit platforms. |
8928 | */ |
8929 | raw_spin_lock_irq(&cpu_rq(cpu)->lock); |
8930 | *cpuusage = val; |
8931 | raw_spin_unlock_irq(&cpu_rq(cpu)->lock); |
8932 | #else |
8933 | *cpuusage = val; |
8934 | #endif |
8935 | } |
8936 | |
8937 | /* return total cpu usage (in nanoseconds) of a group */ |
8938 | static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft) |
8939 | { |
8940 | struct cpuacct *ca = cgroup_ca(cgrp); |
8941 | u64 totalcpuusage = 0; |
8942 | int i; |
8943 | |
8944 | for_each_present_cpu(i) |
8945 | totalcpuusage += cpuacct_cpuusage_read(ca, i); |
8946 | |
8947 | return totalcpuusage; |
8948 | } |
8949 | |
8950 | static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype, |
8951 | u64 reset) |
8952 | { |
8953 | struct cpuacct *ca = cgroup_ca(cgrp); |
8954 | int err = 0; |
8955 | int i; |
8956 | |
8957 | if (reset) { |
8958 | err = -EINVAL; |
8959 | goto out; |
8960 | } |
8961 | |
8962 | for_each_present_cpu(i) |
8963 | cpuacct_cpuusage_write(ca, i, 0); |
8964 | |
8965 | out: |
8966 | return err; |
8967 | } |
8968 | |
8969 | static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft, |
8970 | struct seq_file *m) |
8971 | { |
8972 | struct cpuacct *ca = cgroup_ca(cgroup); |
8973 | u64 percpu; |
8974 | int i; |
8975 | |
8976 | for_each_present_cpu(i) { |
8977 | percpu = cpuacct_cpuusage_read(ca, i); |
8978 | seq_printf(m, "%llu ", (unsigned long long) percpu); |
8979 | } |
8980 | seq_printf(m, "\n"); |
8981 | return 0; |
8982 | } |
8983 | |
8984 | static const char *cpuacct_stat_desc[] = { |
8985 | [CPUACCT_STAT_USER] = "user", |
8986 | [CPUACCT_STAT_SYSTEM] = "system", |
8987 | }; |
8988 | |
8989 | static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft, |
8990 | struct cgroup_map_cb *cb) |
8991 | { |
8992 | struct cpuacct *ca = cgroup_ca(cgrp); |
8993 | int i; |
8994 | |
8995 | for (i = 0; i < CPUACCT_STAT_NSTATS; i++) { |
8996 | s64 val = percpu_counter_read(&ca->cpustat[i]); |
8997 | val = cputime64_to_clock_t(val); |
8998 | cb->fill(cb, cpuacct_stat_desc[i], val); |
8999 | } |
9000 | return 0; |
9001 | } |
9002 | |
9003 | static struct cftype files[] = { |
9004 | { |
9005 | .name = "usage", |
9006 | .read_u64 = cpuusage_read, |
9007 | .write_u64 = cpuusage_write, |
9008 | }, |
9009 | { |
9010 | .name = "usage_percpu", |
9011 | .read_seq_string = cpuacct_percpu_seq_read, |
9012 | }, |
9013 | { |
9014 | .name = "stat", |
9015 | .read_map = cpuacct_stats_show, |
9016 | }, |
9017 | }; |
9018 | |
9019 | static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) |
9020 | { |
9021 | return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files)); |
9022 | } |
9023 | |
9024 | /* |
9025 | * charge this task's execution time to its accounting group. |
9026 | * |
9027 | * called with rq->lock held. |
9028 | */ |
9029 | static void cpuacct_charge(struct task_struct *tsk, u64 cputime) |
9030 | { |
9031 | struct cpuacct *ca; |
9032 | int cpu; |
9033 | |
9034 | if (unlikely(!cpuacct_subsys.active)) |
9035 | return; |
9036 | |
9037 | cpu = task_cpu(tsk); |
9038 | |
9039 | rcu_read_lock(); |
9040 | |
9041 | ca = task_ca(tsk); |
9042 | |
9043 | for (; ca; ca = ca->parent) { |
9044 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
9045 | *cpuusage += cputime; |
9046 | } |
9047 | |
9048 | rcu_read_unlock(); |
9049 | } |
9050 | |
9051 | /* |
9052 | * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large |
9053 | * in cputime_t units. As a result, cpuacct_update_stats calls |
9054 | * percpu_counter_add with values large enough to always overflow the |
9055 | * per cpu batch limit causing bad SMP scalability. |
9056 | * |
9057 | * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we |
9058 | * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled |
9059 | * and enabled. We cap it at INT_MAX which is the largest allowed batch value. |
9060 | */ |
9061 | #ifdef CONFIG_SMP |
9062 | #define CPUACCT_BATCH \ |
9063 | min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX) |
9064 | #else |
9065 | #define CPUACCT_BATCH 0 |
9066 | #endif |
9067 | |
9068 | /* |
9069 | * Charge the system/user time to the task's accounting group. |
9070 | */ |
9071 | static void cpuacct_update_stats(struct task_struct *tsk, |
9072 | enum cpuacct_stat_index idx, cputime_t val) |
9073 | { |
9074 | struct cpuacct *ca; |
9075 | int batch = CPUACCT_BATCH; |
9076 | |
9077 | if (unlikely(!cpuacct_subsys.active)) |
9078 | return; |
9079 | |
9080 | rcu_read_lock(); |
9081 | ca = task_ca(tsk); |
9082 | |
9083 | do { |
9084 | __percpu_counter_add(&ca->cpustat[idx], val, batch); |
9085 | ca = ca->parent; |
9086 | } while (ca); |
9087 | rcu_read_unlock(); |
9088 | } |
9089 | |
9090 | struct cgroup_subsys cpuacct_subsys = { |
9091 | .name = "cpuacct", |
9092 | .create = cpuacct_create, |
9093 | .destroy = cpuacct_destroy, |
9094 | .populate = cpuacct_populate, |
9095 | .subsys_id = cpuacct_subsys_id, |
9096 | }; |
9097 | #endif /* CONFIG_CGROUP_CPUACCT */ |
9098 | |
9099 | #ifndef CONFIG_SMP |
9100 | |
9101 | int rcu_expedited_torture_stats(char *page) |
9102 | { |
9103 | return 0; |
9104 | } |
9105 | EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats); |
9106 | |
9107 | void synchronize_sched_expedited(void) |
9108 | { |
9109 | } |
9110 | EXPORT_SYMBOL_GPL(synchronize_sched_expedited); |
9111 | |
9112 | #else /* #ifndef CONFIG_SMP */ |
9113 | |
9114 | static DEFINE_PER_CPU(struct migration_req, rcu_migration_req); |
9115 | static DEFINE_MUTEX(rcu_sched_expedited_mutex); |
9116 | |
9117 | #define RCU_EXPEDITED_STATE_POST -2 |
9118 | #define RCU_EXPEDITED_STATE_IDLE -1 |
9119 | |
9120 | static int rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE; |
9121 | |
9122 | int rcu_expedited_torture_stats(char *page) |
9123 | { |
9124 | int cnt = 0; |
9125 | int cpu; |
9126 | |
9127 | cnt += sprintf(&page[cnt], "state: %d /", rcu_expedited_state); |
9128 | for_each_online_cpu(cpu) { |
9129 | cnt += sprintf(&page[cnt], " %d:%d", |
9130 | cpu, per_cpu(rcu_migration_req, cpu).dest_cpu); |
9131 | } |
9132 | cnt += sprintf(&page[cnt], "\n"); |
9133 | return cnt; |
9134 | } |
9135 | EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats); |
9136 | |
9137 | static long synchronize_sched_expedited_count; |
9138 | |
9139 | /* |
9140 | * Wait for an rcu-sched grace period to elapse, but use "big hammer" |
9141 | * approach to force grace period to end quickly. This consumes |
9142 | * significant time on all CPUs, and is thus not recommended for |
9143 | * any sort of common-case code. |
9144 | * |
9145 | * Note that it is illegal to call this function while holding any |
9146 | * lock that is acquired by a CPU-hotplug notifier. Failing to |
9147 | * observe this restriction will result in deadlock. |
9148 | */ |
9149 | void synchronize_sched_expedited(void) |
9150 | { |
9151 | int cpu; |
9152 | unsigned long flags; |
9153 | bool need_full_sync = 0; |
9154 | struct rq *rq; |
9155 | struct migration_req *req; |
9156 | long snap; |
9157 | int trycount = 0; |
9158 | |
9159 | smp_mb(); /* ensure prior mod happens before capturing snap. */ |
9160 | snap = ACCESS_ONCE(synchronize_sched_expedited_count) + 1; |
9161 | get_online_cpus(); |
9162 | while (!mutex_trylock(&rcu_sched_expedited_mutex)) { |
9163 | put_online_cpus(); |
9164 | if (trycount++ < 10) |
9165 | udelay(trycount * num_online_cpus()); |
9166 | else { |
9167 | synchronize_sched(); |
9168 | return; |
9169 | } |
9170 | if (ACCESS_ONCE(synchronize_sched_expedited_count) - snap > 0) { |
9171 | smp_mb(); /* ensure test happens before caller kfree */ |
9172 | return; |
9173 | } |
9174 | get_online_cpus(); |
9175 | } |
9176 | rcu_expedited_state = RCU_EXPEDITED_STATE_POST; |
9177 | for_each_online_cpu(cpu) { |
9178 | rq = cpu_rq(cpu); |
9179 | req = &per_cpu(rcu_migration_req, cpu); |
9180 | init_completion(&req->done); |
9181 | req->task = NULL; |
9182 | req->dest_cpu = RCU_MIGRATION_NEED_QS; |
9183 | raw_spin_lock_irqsave(&rq->lock, flags); |
9184 | list_add(&req->list, &rq->migration_queue); |
9185 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
9186 | wake_up_process(rq->migration_thread); |
9187 | } |
9188 | for_each_online_cpu(cpu) { |
9189 | rcu_expedited_state = cpu; |
9190 | req = &per_cpu(rcu_migration_req, cpu); |
9191 | rq = cpu_rq(cpu); |
9192 | wait_for_completion(&req->done); |
9193 | raw_spin_lock_irqsave(&rq->lock, flags); |
9194 | if (unlikely(req->dest_cpu == RCU_MIGRATION_MUST_SYNC)) |
9195 | need_full_sync = 1; |
9196 | req->dest_cpu = RCU_MIGRATION_IDLE; |
9197 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
9198 | } |
9199 | rcu_expedited_state = RCU_EXPEDITED_STATE_IDLE; |
9200 | synchronize_sched_expedited_count++; |
9201 | mutex_unlock(&rcu_sched_expedited_mutex); |
9202 | put_online_cpus(); |
9203 | if (need_full_sync) |
9204 | synchronize_sched(); |
9205 | } |
9206 | EXPORT_SYMBOL_GPL(synchronize_sched_expedited); |
9207 | |
9208 | #endif /* #else #ifndef CONFIG_SMP */ |
9209 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9