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1da177e4 1/*
391e43da 2 * kernel/sched/core.c
1da177e4
LT
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
c31f2e8a
IM
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
b9131769
IM
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
1da177e4
LT
27 */
28
29#include <linux/mm.h>
30#include <linux/module.h>
31#include <linux/nmi.h>
32#include <linux/init.h>
dff06c15 33#include <linux/uaccess.h>
1da177e4 34#include <linux/highmem.h>
1da177e4
LT
35#include <asm/mmu_context.h>
36#include <linux/interrupt.h>
c59ede7b 37#include <linux/capability.h>
1da177e4
LT
38#include <linux/completion.h>
39#include <linux/kernel_stat.h>
9a11b49a 40#include <linux/debug_locks.h>
cdd6c482 41#include <linux/perf_event.h>
1da177e4
LT
42#include <linux/security.h>
43#include <linux/notifier.h>
44#include <linux/profile.h>
7dfb7103 45#include <linux/freezer.h>
198e2f18 46#include <linux/vmalloc.h>
1da177e4
LT
47#include <linux/blkdev.h>
48#include <linux/delay.h>
b488893a 49#include <linux/pid_namespace.h>
1da177e4
LT
50#include <linux/smp.h>
51#include <linux/threads.h>
52#include <linux/timer.h>
53#include <linux/rcupdate.h>
54#include <linux/cpu.h>
55#include <linux/cpuset.h>
56#include <linux/percpu.h>
b5aadf7f 57#include <linux/proc_fs.h>
1da177e4 58#include <linux/seq_file.h>
e692ab53 59#include <linux/sysctl.h>
1da177e4
LT
60#include <linux/syscalls.h>
61#include <linux/times.h>
8f0ab514 62#include <linux/tsacct_kern.h>
c6fd91f0 63#include <linux/kprobes.h>
0ff92245 64#include <linux/delayacct.h>
dff06c15 65#include <linux/unistd.h>
f5ff8422 66#include <linux/pagemap.h>
8f4d37ec 67#include <linux/hrtimer.h>
30914a58 68#include <linux/tick.h>
f00b45c1
PZ
69#include <linux/debugfs.h>
70#include <linux/ctype.h>
6cd8a4bb 71#include <linux/ftrace.h>
5a0e3ad6 72#include <linux/slab.h>
f1c6f1a7 73#include <linux/init_task.h>
40401530 74#include <linux/binfmts.h>
91d1aa43 75#include <linux/context_tracking.h>
1da177e4 76
96f951ed 77#include <asm/switch_to.h>
5517d86b 78#include <asm/tlb.h>
838225b4 79#include <asm/irq_regs.h>
db7e527d 80#include <asm/mutex.h>
e6e6685a
GC
81#ifdef CONFIG_PARAVIRT
82#include <asm/paravirt.h>
83#endif
1da177e4 84
029632fb 85#include "sched.h"
ea138446 86#include "../workqueue_internal.h"
29d5e047 87#include "../smpboot.h"
6e0534f2 88
a8d154b0 89#define CREATE_TRACE_POINTS
ad8d75ff 90#include <trace/events/sched.h>
a8d154b0 91
029632fb 92void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period)
d0b27fa7 93{
58088ad0
PT
94 unsigned long delta;
95 ktime_t soft, hard, now;
d0b27fa7 96
58088ad0
PT
97 for (;;) {
98 if (hrtimer_active(period_timer))
99 break;
100
101 now = hrtimer_cb_get_time(period_timer);
102 hrtimer_forward(period_timer, now, period);
d0b27fa7 103
58088ad0
PT
104 soft = hrtimer_get_softexpires(period_timer);
105 hard = hrtimer_get_expires(period_timer);
106 delta = ktime_to_ns(ktime_sub(hard, soft));
107 __hrtimer_start_range_ns(period_timer, soft, delta,
108 HRTIMER_MODE_ABS_PINNED, 0);
109 }
110}
111
029632fb
PZ
112DEFINE_MUTEX(sched_domains_mutex);
113DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
dc61b1d6 114
fe44d621 115static void update_rq_clock_task(struct rq *rq, s64 delta);
305e6835 116
029632fb 117void update_rq_clock(struct rq *rq)
3e51f33f 118{
fe44d621 119 s64 delta;
305e6835 120
61eadef6 121 if (rq->skip_clock_update > 0)
f26f9aff 122 return;
aa483808 123
fe44d621
PZ
124 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
125 rq->clock += delta;
126 update_rq_clock_task(rq, delta);
3e51f33f
PZ
127}
128
bf5c91ba
IM
129/*
130 * Debugging: various feature bits
131 */
f00b45c1 132
f00b45c1
PZ
133#define SCHED_FEAT(name, enabled) \
134 (1UL << __SCHED_FEAT_##name) * enabled |
135
bf5c91ba 136const_debug unsigned int sysctl_sched_features =
391e43da 137#include "features.h"
f00b45c1
PZ
138 0;
139
140#undef SCHED_FEAT
141
142#ifdef CONFIG_SCHED_DEBUG
143#define SCHED_FEAT(name, enabled) \
144 #name ,
145
1292531f 146static const char * const sched_feat_names[] = {
391e43da 147#include "features.h"
f00b45c1
PZ
148};
149
150#undef SCHED_FEAT
151
34f3a814 152static int sched_feat_show(struct seq_file *m, void *v)
f00b45c1 153{
f00b45c1
PZ
154 int i;
155
f8b6d1cc 156 for (i = 0; i < __SCHED_FEAT_NR; i++) {
34f3a814
LZ
157 if (!(sysctl_sched_features & (1UL << i)))
158 seq_puts(m, "NO_");
159 seq_printf(m, "%s ", sched_feat_names[i]);
f00b45c1 160 }
34f3a814 161 seq_puts(m, "\n");
f00b45c1 162
34f3a814 163 return 0;
f00b45c1
PZ
164}
165
f8b6d1cc
PZ
166#ifdef HAVE_JUMP_LABEL
167
c5905afb
IM
168#define jump_label_key__true STATIC_KEY_INIT_TRUE
169#define jump_label_key__false STATIC_KEY_INIT_FALSE
f8b6d1cc
PZ
170
171#define SCHED_FEAT(name, enabled) \
172 jump_label_key__##enabled ,
173
c5905afb 174struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
f8b6d1cc
PZ
175#include "features.h"
176};
177
178#undef SCHED_FEAT
179
180static void sched_feat_disable(int i)
181{
c5905afb
IM
182 if (static_key_enabled(&sched_feat_keys[i]))
183 static_key_slow_dec(&sched_feat_keys[i]);
f8b6d1cc
PZ
184}
185
186static void sched_feat_enable(int i)
187{
c5905afb
IM
188 if (!static_key_enabled(&sched_feat_keys[i]))
189 static_key_slow_inc(&sched_feat_keys[i]);
f8b6d1cc
PZ
190}
191#else
192static void sched_feat_disable(int i) { };
193static void sched_feat_enable(int i) { };
194#endif /* HAVE_JUMP_LABEL */
195
1a687c2e 196static int sched_feat_set(char *cmp)
f00b45c1 197{
f00b45c1 198 int i;
1a687c2e 199 int neg = 0;
f00b45c1 200
524429c3 201 if (strncmp(cmp, "NO_", 3) == 0) {
f00b45c1
PZ
202 neg = 1;
203 cmp += 3;
204 }
205
f8b6d1cc 206 for (i = 0; i < __SCHED_FEAT_NR; i++) {
7740191c 207 if (strcmp(cmp, sched_feat_names[i]) == 0) {
f8b6d1cc 208 if (neg) {
f00b45c1 209 sysctl_sched_features &= ~(1UL << i);
f8b6d1cc
PZ
210 sched_feat_disable(i);
211 } else {
f00b45c1 212 sysctl_sched_features |= (1UL << i);
f8b6d1cc
PZ
213 sched_feat_enable(i);
214 }
f00b45c1
PZ
215 break;
216 }
217 }
218
1a687c2e
MG
219 return i;
220}
221
222static ssize_t
223sched_feat_write(struct file *filp, const char __user *ubuf,
224 size_t cnt, loff_t *ppos)
225{
226 char buf[64];
227 char *cmp;
228 int i;
229
230 if (cnt > 63)
231 cnt = 63;
232
233 if (copy_from_user(&buf, ubuf, cnt))
234 return -EFAULT;
235
236 buf[cnt] = 0;
237 cmp = strstrip(buf);
238
239 i = sched_feat_set(cmp);
f8b6d1cc 240 if (i == __SCHED_FEAT_NR)
f00b45c1
PZ
241 return -EINVAL;
242
42994724 243 *ppos += cnt;
f00b45c1
PZ
244
245 return cnt;
246}
247
34f3a814
LZ
248static int sched_feat_open(struct inode *inode, struct file *filp)
249{
250 return single_open(filp, sched_feat_show, NULL);
251}
252
828c0950 253static const struct file_operations sched_feat_fops = {
34f3a814
LZ
254 .open = sched_feat_open,
255 .write = sched_feat_write,
256 .read = seq_read,
257 .llseek = seq_lseek,
258 .release = single_release,
f00b45c1
PZ
259};
260
261static __init int sched_init_debug(void)
262{
f00b45c1
PZ
263 debugfs_create_file("sched_features", 0644, NULL, NULL,
264 &sched_feat_fops);
265
266 return 0;
267}
268late_initcall(sched_init_debug);
f8b6d1cc 269#endif /* CONFIG_SCHED_DEBUG */
bf5c91ba 270
b82d9fdd
PZ
271/*
272 * Number of tasks to iterate in a single balance run.
273 * Limited because this is done with IRQs disabled.
274 */
275const_debug unsigned int sysctl_sched_nr_migrate = 32;
276
e9e9250b
PZ
277/*
278 * period over which we average the RT time consumption, measured
279 * in ms.
280 *
281 * default: 1s
282 */
283const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
284
fa85ae24 285/*
9f0c1e56 286 * period over which we measure -rt task cpu usage in us.
fa85ae24
PZ
287 * default: 1s
288 */
9f0c1e56 289unsigned int sysctl_sched_rt_period = 1000000;
fa85ae24 290
029632fb 291__read_mostly int scheduler_running;
6892b75e 292
9f0c1e56
PZ
293/*
294 * part of the period that we allow rt tasks to run in us.
295 * default: 0.95s
296 */
297int sysctl_sched_rt_runtime = 950000;
fa85ae24 298
fa85ae24 299
1da177e4 300
0970d299 301/*
0122ec5b 302 * __task_rq_lock - lock the rq @p resides on.
b29739f9 303 */
70b97a7f 304static inline struct rq *__task_rq_lock(struct task_struct *p)
b29739f9
IM
305 __acquires(rq->lock)
306{
0970d299
PZ
307 struct rq *rq;
308
0122ec5b
PZ
309 lockdep_assert_held(&p->pi_lock);
310
3a5c359a 311 for (;;) {
0970d299 312 rq = task_rq(p);
05fa785c 313 raw_spin_lock(&rq->lock);
65cc8e48 314 if (likely(rq == task_rq(p)))
3a5c359a 315 return rq;
05fa785c 316 raw_spin_unlock(&rq->lock);
b29739f9 317 }
b29739f9
IM
318}
319
1da177e4 320/*
0122ec5b 321 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
1da177e4 322 */
70b97a7f 323static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
0122ec5b 324 __acquires(p->pi_lock)
1da177e4
LT
325 __acquires(rq->lock)
326{
70b97a7f 327 struct rq *rq;
1da177e4 328
3a5c359a 329 for (;;) {
0122ec5b 330 raw_spin_lock_irqsave(&p->pi_lock, *flags);
3a5c359a 331 rq = task_rq(p);
05fa785c 332 raw_spin_lock(&rq->lock);
65cc8e48 333 if (likely(rq == task_rq(p)))
3a5c359a 334 return rq;
0122ec5b
PZ
335 raw_spin_unlock(&rq->lock);
336 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
1da177e4 337 }
1da177e4
LT
338}
339
a9957449 340static void __task_rq_unlock(struct rq *rq)
b29739f9
IM
341 __releases(rq->lock)
342{
05fa785c 343 raw_spin_unlock(&rq->lock);
b29739f9
IM
344}
345
0122ec5b
PZ
346static inline void
347task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
1da177e4 348 __releases(rq->lock)
0122ec5b 349 __releases(p->pi_lock)
1da177e4 350{
0122ec5b
PZ
351 raw_spin_unlock(&rq->lock);
352 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
1da177e4
LT
353}
354
1da177e4 355/*
cc2a73b5 356 * this_rq_lock - lock this runqueue and disable interrupts.
1da177e4 357 */
a9957449 358static struct rq *this_rq_lock(void)
1da177e4
LT
359 __acquires(rq->lock)
360{
70b97a7f 361 struct rq *rq;
1da177e4
LT
362
363 local_irq_disable();
364 rq = this_rq();
05fa785c 365 raw_spin_lock(&rq->lock);
1da177e4
LT
366
367 return rq;
368}
369
8f4d37ec
PZ
370#ifdef CONFIG_SCHED_HRTICK
371/*
372 * Use HR-timers to deliver accurate preemption points.
8f4d37ec 373 */
8f4d37ec 374
8f4d37ec
PZ
375static void hrtick_clear(struct rq *rq)
376{
377 if (hrtimer_active(&rq->hrtick_timer))
378 hrtimer_cancel(&rq->hrtick_timer);
379}
380
8f4d37ec
PZ
381/*
382 * High-resolution timer tick.
383 * Runs from hardirq context with interrupts disabled.
384 */
385static enum hrtimer_restart hrtick(struct hrtimer *timer)
386{
387 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
388
389 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
390
05fa785c 391 raw_spin_lock(&rq->lock);
3e51f33f 392 update_rq_clock(rq);
8f4d37ec 393 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
05fa785c 394 raw_spin_unlock(&rq->lock);
8f4d37ec
PZ
395
396 return HRTIMER_NORESTART;
397}
398
95e904c7 399#ifdef CONFIG_SMP
971ee28c
PZ
400
401static int __hrtick_restart(struct rq *rq)
402{
403 struct hrtimer *timer = &rq->hrtick_timer;
404 ktime_t time = hrtimer_get_softexpires(timer);
405
406 return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0);
407}
408
31656519
PZ
409/*
410 * called from hardirq (IPI) context
411 */
412static void __hrtick_start(void *arg)
b328ca18 413{
31656519 414 struct rq *rq = arg;
b328ca18 415
05fa785c 416 raw_spin_lock(&rq->lock);
971ee28c 417 __hrtick_restart(rq);
31656519 418 rq->hrtick_csd_pending = 0;
05fa785c 419 raw_spin_unlock(&rq->lock);
b328ca18
PZ
420}
421
31656519
PZ
422/*
423 * Called to set the hrtick timer state.
424 *
425 * called with rq->lock held and irqs disabled
426 */
029632fb 427void hrtick_start(struct rq *rq, u64 delay)
b328ca18 428{
31656519
PZ
429 struct hrtimer *timer = &rq->hrtick_timer;
430 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
b328ca18 431
cc584b21 432 hrtimer_set_expires(timer, time);
31656519
PZ
433
434 if (rq == this_rq()) {
971ee28c 435 __hrtick_restart(rq);
31656519 436 } else if (!rq->hrtick_csd_pending) {
6e275637 437 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
31656519
PZ
438 rq->hrtick_csd_pending = 1;
439 }
b328ca18
PZ
440}
441
442static int
443hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
444{
445 int cpu = (int)(long)hcpu;
446
447 switch (action) {
448 case CPU_UP_CANCELED:
449 case CPU_UP_CANCELED_FROZEN:
450 case CPU_DOWN_PREPARE:
451 case CPU_DOWN_PREPARE_FROZEN:
452 case CPU_DEAD:
453 case CPU_DEAD_FROZEN:
31656519 454 hrtick_clear(cpu_rq(cpu));
b328ca18
PZ
455 return NOTIFY_OK;
456 }
457
458 return NOTIFY_DONE;
459}
460
fa748203 461static __init void init_hrtick(void)
b328ca18
PZ
462{
463 hotcpu_notifier(hotplug_hrtick, 0);
464}
31656519
PZ
465#else
466/*
467 * Called to set the hrtick timer state.
468 *
469 * called with rq->lock held and irqs disabled
470 */
029632fb 471void hrtick_start(struct rq *rq, u64 delay)
31656519 472{
7f1e2ca9 473 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
5c333864 474 HRTIMER_MODE_REL_PINNED, 0);
31656519 475}
b328ca18 476
006c75f1 477static inline void init_hrtick(void)
8f4d37ec 478{
8f4d37ec 479}
31656519 480#endif /* CONFIG_SMP */
8f4d37ec 481
31656519 482static void init_rq_hrtick(struct rq *rq)
8f4d37ec 483{
31656519
PZ
484#ifdef CONFIG_SMP
485 rq->hrtick_csd_pending = 0;
8f4d37ec 486
31656519
PZ
487 rq->hrtick_csd.flags = 0;
488 rq->hrtick_csd.func = __hrtick_start;
489 rq->hrtick_csd.info = rq;
490#endif
8f4d37ec 491
31656519
PZ
492 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
493 rq->hrtick_timer.function = hrtick;
8f4d37ec 494}
006c75f1 495#else /* CONFIG_SCHED_HRTICK */
8f4d37ec
PZ
496static inline void hrtick_clear(struct rq *rq)
497{
498}
499
8f4d37ec
PZ
500static inline void init_rq_hrtick(struct rq *rq)
501{
502}
503
b328ca18
PZ
504static inline void init_hrtick(void)
505{
506}
006c75f1 507#endif /* CONFIG_SCHED_HRTICK */
8f4d37ec 508
c24d20db
IM
509/*
510 * resched_task - mark a task 'to be rescheduled now'.
511 *
512 * On UP this means the setting of the need_resched flag, on SMP it
513 * might also involve a cross-CPU call to trigger the scheduler on
514 * the target CPU.
515 */
516#ifdef CONFIG_SMP
029632fb 517void resched_task(struct task_struct *p)
c24d20db
IM
518{
519 int cpu;
520
05fa785c 521 assert_raw_spin_locked(&task_rq(p)->lock);
c24d20db 522
5ed0cec0 523 if (test_tsk_need_resched(p))
c24d20db
IM
524 return;
525
5ed0cec0 526 set_tsk_need_resched(p);
c24d20db
IM
527
528 cpu = task_cpu(p);
529 if (cpu == smp_processor_id())
530 return;
531
532 /* NEED_RESCHED must be visible before we test polling */
533 smp_mb();
534 if (!tsk_is_polling(p))
535 smp_send_reschedule(cpu);
536}
537
029632fb 538void resched_cpu(int cpu)
c24d20db
IM
539{
540 struct rq *rq = cpu_rq(cpu);
541 unsigned long flags;
542
05fa785c 543 if (!raw_spin_trylock_irqsave(&rq->lock, flags))
c24d20db
IM
544 return;
545 resched_task(cpu_curr(cpu));
05fa785c 546 raw_spin_unlock_irqrestore(&rq->lock, flags);
c24d20db 547}
06d8308c 548
3451d024 549#ifdef CONFIG_NO_HZ_COMMON
83cd4fe2
VP
550/*
551 * In the semi idle case, use the nearest busy cpu for migrating timers
552 * from an idle cpu. This is good for power-savings.
553 *
554 * We don't do similar optimization for completely idle system, as
555 * selecting an idle cpu will add more delays to the timers than intended
556 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
557 */
558int get_nohz_timer_target(void)
559{
560 int cpu = smp_processor_id();
561 int i;
562 struct sched_domain *sd;
563
057f3fad 564 rcu_read_lock();
83cd4fe2 565 for_each_domain(cpu, sd) {
057f3fad
PZ
566 for_each_cpu(i, sched_domain_span(sd)) {
567 if (!idle_cpu(i)) {
568 cpu = i;
569 goto unlock;
570 }
571 }
83cd4fe2 572 }
057f3fad
PZ
573unlock:
574 rcu_read_unlock();
83cd4fe2
VP
575 return cpu;
576}
06d8308c
TG
577/*
578 * When add_timer_on() enqueues a timer into the timer wheel of an
579 * idle CPU then this timer might expire before the next timer event
580 * which is scheduled to wake up that CPU. In case of a completely
581 * idle system the next event might even be infinite time into the
582 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
583 * leaves the inner idle loop so the newly added timer is taken into
584 * account when the CPU goes back to idle and evaluates the timer
585 * wheel for the next timer event.
586 */
1c20091e 587static void wake_up_idle_cpu(int cpu)
06d8308c
TG
588{
589 struct rq *rq = cpu_rq(cpu);
590
591 if (cpu == smp_processor_id())
592 return;
593
594 /*
595 * This is safe, as this function is called with the timer
596 * wheel base lock of (cpu) held. When the CPU is on the way
597 * to idle and has not yet set rq->curr to idle then it will
598 * be serialized on the timer wheel base lock and take the new
599 * timer into account automatically.
600 */
601 if (rq->curr != rq->idle)
602 return;
45bf76df 603
45bf76df 604 /*
06d8308c
TG
605 * We can set TIF_RESCHED on the idle task of the other CPU
606 * lockless. The worst case is that the other CPU runs the
607 * idle task through an additional NOOP schedule()
45bf76df 608 */
5ed0cec0 609 set_tsk_need_resched(rq->idle);
45bf76df 610
06d8308c
TG
611 /* NEED_RESCHED must be visible before we test polling */
612 smp_mb();
613 if (!tsk_is_polling(rq->idle))
614 smp_send_reschedule(cpu);
45bf76df
IM
615}
616
c5bfece2 617static bool wake_up_full_nohz_cpu(int cpu)
1c20091e 618{
c5bfece2 619 if (tick_nohz_full_cpu(cpu)) {
1c20091e
FW
620 if (cpu != smp_processor_id() ||
621 tick_nohz_tick_stopped())
622 smp_send_reschedule(cpu);
623 return true;
624 }
625
626 return false;
627}
628
629void wake_up_nohz_cpu(int cpu)
630{
c5bfece2 631 if (!wake_up_full_nohz_cpu(cpu))
1c20091e
FW
632 wake_up_idle_cpu(cpu);
633}
634
ca38062e 635static inline bool got_nohz_idle_kick(void)
45bf76df 636{
1c792db7 637 int cpu = smp_processor_id();
873b4c65
VG
638
639 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)))
640 return false;
641
642 if (idle_cpu(cpu) && !need_resched())
643 return true;
644
645 /*
646 * We can't run Idle Load Balance on this CPU for this time so we
647 * cancel it and clear NOHZ_BALANCE_KICK
648 */
649 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));
650 return false;
45bf76df
IM
651}
652
3451d024 653#else /* CONFIG_NO_HZ_COMMON */
45bf76df 654
ca38062e 655static inline bool got_nohz_idle_kick(void)
2069dd75 656{
ca38062e 657 return false;
2069dd75
PZ
658}
659
3451d024 660#endif /* CONFIG_NO_HZ_COMMON */
d842de87 661
ce831b38
FW
662#ifdef CONFIG_NO_HZ_FULL
663bool sched_can_stop_tick(void)
664{
665 struct rq *rq;
666
667 rq = this_rq();
668
669 /* Make sure rq->nr_running update is visible after the IPI */
670 smp_rmb();
671
672 /* More than one running task need preemption */
673 if (rq->nr_running > 1)
674 return false;
675
676 return true;
677}
678#endif /* CONFIG_NO_HZ_FULL */
d842de87 679
029632fb 680void sched_avg_update(struct rq *rq)
18d95a28 681{
e9e9250b
PZ
682 s64 period = sched_avg_period();
683
78becc27 684 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) {
0d98bb26
WD
685 /*
686 * Inline assembly required to prevent the compiler
687 * optimising this loop into a divmod call.
688 * See __iter_div_u64_rem() for another example of this.
689 */
690 asm("" : "+rm" (rq->age_stamp));
e9e9250b
PZ
691 rq->age_stamp += period;
692 rq->rt_avg /= 2;
693 }
18d95a28
PZ
694}
695
6d6bc0ad 696#else /* !CONFIG_SMP */
029632fb 697void resched_task(struct task_struct *p)
18d95a28 698{
05fa785c 699 assert_raw_spin_locked(&task_rq(p)->lock);
31656519 700 set_tsk_need_resched(p);
18d95a28 701}
6d6bc0ad 702#endif /* CONFIG_SMP */
18d95a28 703
a790de99
PT
704#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
705 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
c09595f6 706/*
8277434e
PT
707 * Iterate task_group tree rooted at *from, calling @down when first entering a
708 * node and @up when leaving it for the final time.
709 *
710 * Caller must hold rcu_lock or sufficient equivalent.
c09595f6 711 */
029632fb 712int walk_tg_tree_from(struct task_group *from,
8277434e 713 tg_visitor down, tg_visitor up, void *data)
c09595f6
PZ
714{
715 struct task_group *parent, *child;
eb755805 716 int ret;
c09595f6 717
8277434e
PT
718 parent = from;
719
c09595f6 720down:
eb755805
PZ
721 ret = (*down)(parent, data);
722 if (ret)
8277434e 723 goto out;
c09595f6
PZ
724 list_for_each_entry_rcu(child, &parent->children, siblings) {
725 parent = child;
726 goto down;
727
728up:
729 continue;
730 }
eb755805 731 ret = (*up)(parent, data);
8277434e
PT
732 if (ret || parent == from)
733 goto out;
c09595f6
PZ
734
735 child = parent;
736 parent = parent->parent;
737 if (parent)
738 goto up;
8277434e 739out:
eb755805 740 return ret;
c09595f6
PZ
741}
742
029632fb 743int tg_nop(struct task_group *tg, void *data)
eb755805 744{
e2b245f8 745 return 0;
eb755805 746}
18d95a28
PZ
747#endif
748
45bf76df
IM
749static void set_load_weight(struct task_struct *p)
750{
f05998d4
NR
751 int prio = p->static_prio - MAX_RT_PRIO;
752 struct load_weight *load = &p->se.load;
753
dd41f596
IM
754 /*
755 * SCHED_IDLE tasks get minimal weight:
756 */
757 if (p->policy == SCHED_IDLE) {
c8b28116 758 load->weight = scale_load(WEIGHT_IDLEPRIO);
f05998d4 759 load->inv_weight = WMULT_IDLEPRIO;
dd41f596
IM
760 return;
761 }
71f8bd46 762
c8b28116 763 load->weight = scale_load(prio_to_weight[prio]);
f05998d4 764 load->inv_weight = prio_to_wmult[prio];
71f8bd46
IM
765}
766
371fd7e7 767static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
2087a1ad 768{
a64692a3 769 update_rq_clock(rq);
dd41f596 770 sched_info_queued(p);
371fd7e7 771 p->sched_class->enqueue_task(rq, p, flags);
71f8bd46
IM
772}
773
371fd7e7 774static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
71f8bd46 775{
a64692a3 776 update_rq_clock(rq);
46ac22ba 777 sched_info_dequeued(p);
371fd7e7 778 p->sched_class->dequeue_task(rq, p, flags);
71f8bd46
IM
779}
780
029632fb 781void activate_task(struct rq *rq, struct task_struct *p, int flags)
1e3c88bd
PZ
782{
783 if (task_contributes_to_load(p))
784 rq->nr_uninterruptible--;
785
371fd7e7 786 enqueue_task(rq, p, flags);
1e3c88bd
PZ
787}
788
029632fb 789void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
1e3c88bd
PZ
790{
791 if (task_contributes_to_load(p))
792 rq->nr_uninterruptible++;
793
371fd7e7 794 dequeue_task(rq, p, flags);
1e3c88bd
PZ
795}
796
fe44d621 797static void update_rq_clock_task(struct rq *rq, s64 delta)
aa483808 798{
095c0aa8
GC
799/*
800 * In theory, the compile should just see 0 here, and optimize out the call
801 * to sched_rt_avg_update. But I don't trust it...
802 */
803#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
804 s64 steal = 0, irq_delta = 0;
805#endif
806#ifdef CONFIG_IRQ_TIME_ACCOUNTING
8e92c201 807 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
fe44d621
PZ
808
809 /*
810 * Since irq_time is only updated on {soft,}irq_exit, we might run into
811 * this case when a previous update_rq_clock() happened inside a
812 * {soft,}irq region.
813 *
814 * When this happens, we stop ->clock_task and only update the
815 * prev_irq_time stamp to account for the part that fit, so that a next
816 * update will consume the rest. This ensures ->clock_task is
817 * monotonic.
818 *
819 * It does however cause some slight miss-attribution of {soft,}irq
820 * time, a more accurate solution would be to update the irq_time using
821 * the current rq->clock timestamp, except that would require using
822 * atomic ops.
823 */
824 if (irq_delta > delta)
825 irq_delta = delta;
826
827 rq->prev_irq_time += irq_delta;
828 delta -= irq_delta;
095c0aa8
GC
829#endif
830#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
c5905afb 831 if (static_key_false((&paravirt_steal_rq_enabled))) {
095c0aa8
GC
832 u64 st;
833
834 steal = paravirt_steal_clock(cpu_of(rq));
835 steal -= rq->prev_steal_time_rq;
836
837 if (unlikely(steal > delta))
838 steal = delta;
839
840 st = steal_ticks(steal);
841 steal = st * TICK_NSEC;
842
843 rq->prev_steal_time_rq += steal;
844
845 delta -= steal;
846 }
847#endif
848
fe44d621
PZ
849 rq->clock_task += delta;
850
095c0aa8
GC
851#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
852 if ((irq_delta + steal) && sched_feat(NONTASK_POWER))
853 sched_rt_avg_update(rq, irq_delta + steal);
854#endif
aa483808
VP
855}
856
34f971f6
PZ
857void sched_set_stop_task(int cpu, struct task_struct *stop)
858{
859 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
860 struct task_struct *old_stop = cpu_rq(cpu)->stop;
861
862 if (stop) {
863 /*
864 * Make it appear like a SCHED_FIFO task, its something
865 * userspace knows about and won't get confused about.
866 *
867 * Also, it will make PI more or less work without too
868 * much confusion -- but then, stop work should not
869 * rely on PI working anyway.
870 */
871 sched_setscheduler_nocheck(stop, SCHED_FIFO, &param);
872
873 stop->sched_class = &stop_sched_class;
874 }
875
876 cpu_rq(cpu)->stop = stop;
877
878 if (old_stop) {
879 /*
880 * Reset it back to a normal scheduling class so that
881 * it can die in pieces.
882 */
883 old_stop->sched_class = &rt_sched_class;
884 }
885}
886
14531189 887/*
dd41f596 888 * __normal_prio - return the priority that is based on the static prio
14531189 889 */
14531189
IM
890static inline int __normal_prio(struct task_struct *p)
891{
dd41f596 892 return p->static_prio;
14531189
IM
893}
894
b29739f9
IM
895/*
896 * Calculate the expected normal priority: i.e. priority
897 * without taking RT-inheritance into account. Might be
898 * boosted by interactivity modifiers. Changes upon fork,
899 * setprio syscalls, and whenever the interactivity
900 * estimator recalculates.
901 */
36c8b586 902static inline int normal_prio(struct task_struct *p)
b29739f9
IM
903{
904 int prio;
905
e05606d3 906 if (task_has_rt_policy(p))
b29739f9
IM
907 prio = MAX_RT_PRIO-1 - p->rt_priority;
908 else
909 prio = __normal_prio(p);
910 return prio;
911}
912
913/*
914 * Calculate the current priority, i.e. the priority
915 * taken into account by the scheduler. This value might
916 * be boosted by RT tasks, or might be boosted by
917 * interactivity modifiers. Will be RT if the task got
918 * RT-boosted. If not then it returns p->normal_prio.
919 */
36c8b586 920static int effective_prio(struct task_struct *p)
b29739f9
IM
921{
922 p->normal_prio = normal_prio(p);
923 /*
924 * If we are RT tasks or we were boosted to RT priority,
925 * keep the priority unchanged. Otherwise, update priority
926 * to the normal priority:
927 */
928 if (!rt_prio(p->prio))
929 return p->normal_prio;
930 return p->prio;
931}
932
1da177e4
LT
933/**
934 * task_curr - is this task currently executing on a CPU?
935 * @p: the task in question.
e69f6186
YB
936 *
937 * Return: 1 if the task is currently executing. 0 otherwise.
1da177e4 938 */
36c8b586 939inline int task_curr(const struct task_struct *p)
1da177e4
LT
940{
941 return cpu_curr(task_cpu(p)) == p;
942}
943
cb469845
SR
944static inline void check_class_changed(struct rq *rq, struct task_struct *p,
945 const struct sched_class *prev_class,
da7a735e 946 int oldprio)
cb469845
SR
947{
948 if (prev_class != p->sched_class) {
949 if (prev_class->switched_from)
da7a735e
PZ
950 prev_class->switched_from(rq, p);
951 p->sched_class->switched_to(rq, p);
952 } else if (oldprio != p->prio)
953 p->sched_class->prio_changed(rq, p, oldprio);
cb469845
SR
954}
955
029632fb 956void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
1e5a7405
PZ
957{
958 const struct sched_class *class;
959
960 if (p->sched_class == rq->curr->sched_class) {
961 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
962 } else {
963 for_each_class(class) {
964 if (class == rq->curr->sched_class)
965 break;
966 if (class == p->sched_class) {
967 resched_task(rq->curr);
968 break;
969 }
970 }
971 }
972
973 /*
974 * A queue event has occurred, and we're going to schedule. In
975 * this case, we can save a useless back to back clock update.
976 */
fd2f4419 977 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr))
1e5a7405
PZ
978 rq->skip_clock_update = 1;
979}
980
1da177e4 981#ifdef CONFIG_SMP
dd41f596 982void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
c65cc870 983{
e2912009
PZ
984#ifdef CONFIG_SCHED_DEBUG
985 /*
986 * We should never call set_task_cpu() on a blocked task,
987 * ttwu() will sort out the placement.
988 */
077614ee
PZ
989 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
990 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
0122ec5b
PZ
991
992#ifdef CONFIG_LOCKDEP
6c6c54e1
PZ
993 /*
994 * The caller should hold either p->pi_lock or rq->lock, when changing
995 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
996 *
997 * sched_move_task() holds both and thus holding either pins the cgroup,
8323f26c 998 * see task_group().
6c6c54e1
PZ
999 *
1000 * Furthermore, all task_rq users should acquire both locks, see
1001 * task_rq_lock().
1002 */
0122ec5b
PZ
1003 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
1004 lockdep_is_held(&task_rq(p)->lock)));
1005#endif
e2912009
PZ
1006#endif
1007
de1d7286 1008 trace_sched_migrate_task(p, new_cpu);
cbc34ed1 1009
0c69774e 1010 if (task_cpu(p) != new_cpu) {
0a74bef8
PT
1011 if (p->sched_class->migrate_task_rq)
1012 p->sched_class->migrate_task_rq(p, new_cpu);
0c69774e 1013 p->se.nr_migrations++;
a8b0ca17 1014 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);
0c69774e 1015 }
dd41f596
IM
1016
1017 __set_task_cpu(p, new_cpu);
c65cc870
IM
1018}
1019
969c7921 1020struct migration_arg {
36c8b586 1021 struct task_struct *task;
1da177e4 1022 int dest_cpu;
70b97a7f 1023};
1da177e4 1024
969c7921
TH
1025static int migration_cpu_stop(void *data);
1026
1da177e4
LT
1027/*
1028 * wait_task_inactive - wait for a thread to unschedule.
1029 *
85ba2d86
RM
1030 * If @match_state is nonzero, it's the @p->state value just checked and
1031 * not expected to change. If it changes, i.e. @p might have woken up,
1032 * then return zero. When we succeed in waiting for @p to be off its CPU,
1033 * we return a positive number (its total switch count). If a second call
1034 * a short while later returns the same number, the caller can be sure that
1035 * @p has remained unscheduled the whole time.
1036 *
1da177e4
LT
1037 * The caller must ensure that the task *will* unschedule sometime soon,
1038 * else this function might spin for a *long* time. This function can't
1039 * be called with interrupts off, or it may introduce deadlock with
1040 * smp_call_function() if an IPI is sent by the same process we are
1041 * waiting to become inactive.
1042 */
85ba2d86 1043unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1da177e4
LT
1044{
1045 unsigned long flags;
dd41f596 1046 int running, on_rq;
85ba2d86 1047 unsigned long ncsw;
70b97a7f 1048 struct rq *rq;
1da177e4 1049
3a5c359a
AK
1050 for (;;) {
1051 /*
1052 * We do the initial early heuristics without holding
1053 * any task-queue locks at all. We'll only try to get
1054 * the runqueue lock when things look like they will
1055 * work out!
1056 */
1057 rq = task_rq(p);
fa490cfd 1058
3a5c359a
AK
1059 /*
1060 * If the task is actively running on another CPU
1061 * still, just relax and busy-wait without holding
1062 * any locks.
1063 *
1064 * NOTE! Since we don't hold any locks, it's not
1065 * even sure that "rq" stays as the right runqueue!
1066 * But we don't care, since "task_running()" will
1067 * return false if the runqueue has changed and p
1068 * is actually now running somewhere else!
1069 */
85ba2d86
RM
1070 while (task_running(rq, p)) {
1071 if (match_state && unlikely(p->state != match_state))
1072 return 0;
3a5c359a 1073 cpu_relax();
85ba2d86 1074 }
fa490cfd 1075
3a5c359a
AK
1076 /*
1077 * Ok, time to look more closely! We need the rq
1078 * lock now, to be *sure*. If we're wrong, we'll
1079 * just go back and repeat.
1080 */
1081 rq = task_rq_lock(p, &flags);
27a9da65 1082 trace_sched_wait_task(p);
3a5c359a 1083 running = task_running(rq, p);
fd2f4419 1084 on_rq = p->on_rq;
85ba2d86 1085 ncsw = 0;
f31e11d8 1086 if (!match_state || p->state == match_state)
93dcf55f 1087 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
0122ec5b 1088 task_rq_unlock(rq, p, &flags);
fa490cfd 1089
85ba2d86
RM
1090 /*
1091 * If it changed from the expected state, bail out now.
1092 */
1093 if (unlikely(!ncsw))
1094 break;
1095
3a5c359a
AK
1096 /*
1097 * Was it really running after all now that we
1098 * checked with the proper locks actually held?
1099 *
1100 * Oops. Go back and try again..
1101 */
1102 if (unlikely(running)) {
1103 cpu_relax();
1104 continue;
1105 }
fa490cfd 1106
3a5c359a
AK
1107 /*
1108 * It's not enough that it's not actively running,
1109 * it must be off the runqueue _entirely_, and not
1110 * preempted!
1111 *
80dd99b3 1112 * So if it was still runnable (but just not actively
3a5c359a
AK
1113 * running right now), it's preempted, and we should
1114 * yield - it could be a while.
1115 */
1116 if (unlikely(on_rq)) {
8eb90c30
TG
1117 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
1118
1119 set_current_state(TASK_UNINTERRUPTIBLE);
1120 schedule_hrtimeout(&to, HRTIMER_MODE_REL);
3a5c359a
AK
1121 continue;
1122 }
fa490cfd 1123
3a5c359a
AK
1124 /*
1125 * Ahh, all good. It wasn't running, and it wasn't
1126 * runnable, which means that it will never become
1127 * running in the future either. We're all done!
1128 */
1129 break;
1130 }
85ba2d86
RM
1131
1132 return ncsw;
1da177e4
LT
1133}
1134
1135/***
1136 * kick_process - kick a running thread to enter/exit the kernel
1137 * @p: the to-be-kicked thread
1138 *
1139 * Cause a process which is running on another CPU to enter
1140 * kernel-mode, without any delay. (to get signals handled.)
1141 *
25985edc 1142 * NOTE: this function doesn't have to take the runqueue lock,
1da177e4
LT
1143 * because all it wants to ensure is that the remote task enters
1144 * the kernel. If the IPI races and the task has been migrated
1145 * to another CPU then no harm is done and the purpose has been
1146 * achieved as well.
1147 */
36c8b586 1148void kick_process(struct task_struct *p)
1da177e4
LT
1149{
1150 int cpu;
1151
1152 preempt_disable();
1153 cpu = task_cpu(p);
1154 if ((cpu != smp_processor_id()) && task_curr(p))
1155 smp_send_reschedule(cpu);
1156 preempt_enable();
1157}
b43e3521 1158EXPORT_SYMBOL_GPL(kick_process);
476d139c 1159#endif /* CONFIG_SMP */
1da177e4 1160
970b13ba 1161#ifdef CONFIG_SMP
30da688e 1162/*
013fdb80 1163 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
30da688e 1164 */
5da9a0fb
PZ
1165static int select_fallback_rq(int cpu, struct task_struct *p)
1166{
aa00d89c
TC
1167 int nid = cpu_to_node(cpu);
1168 const struct cpumask *nodemask = NULL;
2baab4e9
PZ
1169 enum { cpuset, possible, fail } state = cpuset;
1170 int dest_cpu;
5da9a0fb 1171
aa00d89c
TC
1172 /*
1173 * If the node that the cpu is on has been offlined, cpu_to_node()
1174 * will return -1. There is no cpu on the node, and we should
1175 * select the cpu on the other node.
1176 */
1177 if (nid != -1) {
1178 nodemask = cpumask_of_node(nid);
1179
1180 /* Look for allowed, online CPU in same node. */
1181 for_each_cpu(dest_cpu, nodemask) {
1182 if (!cpu_online(dest_cpu))
1183 continue;
1184 if (!cpu_active(dest_cpu))
1185 continue;
1186 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
1187 return dest_cpu;
1188 }
2baab4e9 1189 }
5da9a0fb 1190
2baab4e9
PZ
1191 for (;;) {
1192 /* Any allowed, online CPU? */
e3831edd 1193 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) {
2baab4e9
PZ
1194 if (!cpu_online(dest_cpu))
1195 continue;
1196 if (!cpu_active(dest_cpu))
1197 continue;
1198 goto out;
1199 }
5da9a0fb 1200
2baab4e9
PZ
1201 switch (state) {
1202 case cpuset:
1203 /* No more Mr. Nice Guy. */
1204 cpuset_cpus_allowed_fallback(p);
1205 state = possible;
1206 break;
1207
1208 case possible:
1209 do_set_cpus_allowed(p, cpu_possible_mask);
1210 state = fail;
1211 break;
1212
1213 case fail:
1214 BUG();
1215 break;
1216 }
1217 }
1218
1219out:
1220 if (state != cpuset) {
1221 /*
1222 * Don't tell them about moving exiting tasks or
1223 * kernel threads (both mm NULL), since they never
1224 * leave kernel.
1225 */
1226 if (p->mm && printk_ratelimit()) {
1227 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1228 task_pid_nr(p), p->comm, cpu);
1229 }
5da9a0fb
PZ
1230 }
1231
1232 return dest_cpu;
1233}
1234
e2912009 1235/*
013fdb80 1236 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
e2912009 1237 */
970b13ba 1238static inline
7608dec2 1239int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
970b13ba 1240{
7608dec2 1241 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
e2912009
PZ
1242
1243 /*
1244 * In order not to call set_task_cpu() on a blocking task we need
1245 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1246 * cpu.
1247 *
1248 * Since this is common to all placement strategies, this lives here.
1249 *
1250 * [ this allows ->select_task() to simply return task_cpu(p) and
1251 * not worry about this generic constraint ]
1252 */
fa17b507 1253 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
70f11205 1254 !cpu_online(cpu)))
5da9a0fb 1255 cpu = select_fallback_rq(task_cpu(p), p);
e2912009
PZ
1256
1257 return cpu;
970b13ba 1258}
09a40af5
MG
1259
1260static void update_avg(u64 *avg, u64 sample)
1261{
1262 s64 diff = sample - *avg;
1263 *avg += diff >> 3;
1264}
970b13ba
PZ
1265#endif
1266
d7c01d27 1267static void
b84cb5df 1268ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
9ed3811a 1269{
d7c01d27 1270#ifdef CONFIG_SCHEDSTATS
b84cb5df
PZ
1271 struct rq *rq = this_rq();
1272
d7c01d27
PZ
1273#ifdef CONFIG_SMP
1274 int this_cpu = smp_processor_id();
1275
1276 if (cpu == this_cpu) {
1277 schedstat_inc(rq, ttwu_local);
1278 schedstat_inc(p, se.statistics.nr_wakeups_local);
1279 } else {
1280 struct sched_domain *sd;
1281
1282 schedstat_inc(p, se.statistics.nr_wakeups_remote);
057f3fad 1283 rcu_read_lock();
d7c01d27
PZ
1284 for_each_domain(this_cpu, sd) {
1285 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
1286 schedstat_inc(sd, ttwu_wake_remote);
1287 break;
1288 }
1289 }
057f3fad 1290 rcu_read_unlock();
d7c01d27 1291 }
f339b9dc
PZ
1292
1293 if (wake_flags & WF_MIGRATED)
1294 schedstat_inc(p, se.statistics.nr_wakeups_migrate);
1295
d7c01d27
PZ
1296#endif /* CONFIG_SMP */
1297
1298 schedstat_inc(rq, ttwu_count);
9ed3811a 1299 schedstat_inc(p, se.statistics.nr_wakeups);
d7c01d27
PZ
1300
1301 if (wake_flags & WF_SYNC)
9ed3811a 1302 schedstat_inc(p, se.statistics.nr_wakeups_sync);
d7c01d27 1303
d7c01d27
PZ
1304#endif /* CONFIG_SCHEDSTATS */
1305}
1306
1307static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
1308{
9ed3811a 1309 activate_task(rq, p, en_flags);
fd2f4419 1310 p->on_rq = 1;
c2f7115e
PZ
1311
1312 /* if a worker is waking up, notify workqueue */
1313 if (p->flags & PF_WQ_WORKER)
1314 wq_worker_waking_up(p, cpu_of(rq));
9ed3811a
TH
1315}
1316
23f41eeb
PZ
1317/*
1318 * Mark the task runnable and perform wakeup-preemption.
1319 */
89363381 1320static void
23f41eeb 1321ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
9ed3811a 1322{
9ed3811a 1323 check_preempt_curr(rq, p, wake_flags);
a8d7ad52 1324 trace_sched_wakeup(p, true);
9ed3811a
TH
1325
1326 p->state = TASK_RUNNING;
1327#ifdef CONFIG_SMP
1328 if (p->sched_class->task_woken)
1329 p->sched_class->task_woken(rq, p);
1330
e69c6341 1331 if (rq->idle_stamp) {
78becc27 1332 u64 delta = rq_clock(rq) - rq->idle_stamp;
9ed3811a
TH
1333 u64 max = 2*sysctl_sched_migration_cost;
1334
1335 if (delta > max)
1336 rq->avg_idle = max;
1337 else
1338 update_avg(&rq->avg_idle, delta);
1339 rq->idle_stamp = 0;
1340 }
1341#endif
1342}
1343
c05fbafb
PZ
1344static void
1345ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
1346{
1347#ifdef CONFIG_SMP
1348 if (p->sched_contributes_to_load)
1349 rq->nr_uninterruptible--;
1350#endif
1351
1352 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
1353 ttwu_do_wakeup(rq, p, wake_flags);
1354}
1355
1356/*
1357 * Called in case the task @p isn't fully descheduled from its runqueue,
1358 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1359 * since all we need to do is flip p->state to TASK_RUNNING, since
1360 * the task is still ->on_rq.
1361 */
1362static int ttwu_remote(struct task_struct *p, int wake_flags)
1363{
1364 struct rq *rq;
1365 int ret = 0;
1366
1367 rq = __task_rq_lock(p);
1368 if (p->on_rq) {
1ad4ec0d
FW
1369 /* check_preempt_curr() may use rq clock */
1370 update_rq_clock(rq);
c05fbafb
PZ
1371 ttwu_do_wakeup(rq, p, wake_flags);
1372 ret = 1;
1373 }
1374 __task_rq_unlock(rq);
1375
1376 return ret;
1377}
1378
317f3941 1379#ifdef CONFIG_SMP
fa14ff4a 1380static void sched_ttwu_pending(void)
317f3941
PZ
1381{
1382 struct rq *rq = this_rq();
fa14ff4a
PZ
1383 struct llist_node *llist = llist_del_all(&rq->wake_list);
1384 struct task_struct *p;
317f3941
PZ
1385
1386 raw_spin_lock(&rq->lock);
1387
fa14ff4a
PZ
1388 while (llist) {
1389 p = llist_entry(llist, struct task_struct, wake_entry);
1390 llist = llist_next(llist);
317f3941
PZ
1391 ttwu_do_activate(rq, p, 0);
1392 }
1393
1394 raw_spin_unlock(&rq->lock);
1395}
1396
1397void scheduler_ipi(void)
1398{
873b4c65
VG
1399 if (llist_empty(&this_rq()->wake_list)
1400 && !tick_nohz_full_cpu(smp_processor_id())
1401 && !got_nohz_idle_kick())
c5d753a5
PZ
1402 return;
1403
1404 /*
1405 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1406 * traditionally all their work was done from the interrupt return
1407 * path. Now that we actually do some work, we need to make sure
1408 * we do call them.
1409 *
1410 * Some archs already do call them, luckily irq_enter/exit nest
1411 * properly.
1412 *
1413 * Arguably we should visit all archs and update all handlers,
1414 * however a fair share of IPIs are still resched only so this would
1415 * somewhat pessimize the simple resched case.
1416 */
1417 irq_enter();
ff442c51 1418 tick_nohz_full_check();
fa14ff4a 1419 sched_ttwu_pending();
ca38062e
SS
1420
1421 /*
1422 * Check if someone kicked us for doing the nohz idle load balance.
1423 */
873b4c65 1424 if (unlikely(got_nohz_idle_kick())) {
6eb57e0d 1425 this_rq()->idle_balance = 1;
ca38062e 1426 raise_softirq_irqoff(SCHED_SOFTIRQ);
6eb57e0d 1427 }
c5d753a5 1428 irq_exit();
317f3941
PZ
1429}
1430
1431static void ttwu_queue_remote(struct task_struct *p, int cpu)
1432{
fa14ff4a 1433 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list))
317f3941
PZ
1434 smp_send_reschedule(cpu);
1435}
d6aa8f85 1436
39be3501 1437bool cpus_share_cache(int this_cpu, int that_cpu)
518cd623
PZ
1438{
1439 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
1440}
d6aa8f85 1441#endif /* CONFIG_SMP */
317f3941 1442
c05fbafb
PZ
1443static void ttwu_queue(struct task_struct *p, int cpu)
1444{
1445 struct rq *rq = cpu_rq(cpu);
1446
17d9f311 1447#if defined(CONFIG_SMP)
39be3501 1448 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) {
f01114cb 1449 sched_clock_cpu(cpu); /* sync clocks x-cpu */
317f3941
PZ
1450 ttwu_queue_remote(p, cpu);
1451 return;
1452 }
1453#endif
1454
c05fbafb
PZ
1455 raw_spin_lock(&rq->lock);
1456 ttwu_do_activate(rq, p, 0);
1457 raw_spin_unlock(&rq->lock);
9ed3811a
TH
1458}
1459
1460/**
1da177e4 1461 * try_to_wake_up - wake up a thread
9ed3811a 1462 * @p: the thread to be awakened
1da177e4 1463 * @state: the mask of task states that can be woken
9ed3811a 1464 * @wake_flags: wake modifier flags (WF_*)
1da177e4
LT
1465 *
1466 * Put it on the run-queue if it's not already there. The "current"
1467 * thread is always on the run-queue (except when the actual
1468 * re-schedule is in progress), and as such you're allowed to do
1469 * the simpler "current->state = TASK_RUNNING" to mark yourself
1470 * runnable without the overhead of this.
1471 *
e69f6186 1472 * Return: %true if @p was woken up, %false if it was already running.
9ed3811a 1473 * or @state didn't match @p's state.
1da177e4 1474 */
e4a52bcb
PZ
1475static int
1476try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
1da177e4 1477{
1da177e4 1478 unsigned long flags;
c05fbafb 1479 int cpu, success = 0;
2398f2c6 1480
e0acd0a6
ON
1481 /*
1482 * If we are going to wake up a thread waiting for CONDITION we
1483 * need to ensure that CONDITION=1 done by the caller can not be
1484 * reordered with p->state check below. This pairs with mb() in
1485 * set_current_state() the waiting thread does.
1486 */
1487 smp_mb__before_spinlock();
013fdb80 1488 raw_spin_lock_irqsave(&p->pi_lock, flags);
e9c84311 1489 if (!(p->state & state))
1da177e4
LT
1490 goto out;
1491
c05fbafb 1492 success = 1; /* we're going to change ->state */
1da177e4 1493 cpu = task_cpu(p);
1da177e4 1494
c05fbafb
PZ
1495 if (p->on_rq && ttwu_remote(p, wake_flags))
1496 goto stat;
1da177e4 1497
1da177e4 1498#ifdef CONFIG_SMP
e9c84311 1499 /*
c05fbafb
PZ
1500 * If the owning (remote) cpu is still in the middle of schedule() with
1501 * this task as prev, wait until its done referencing the task.
e9c84311 1502 */
f3e94786 1503 while (p->on_cpu)
e4a52bcb 1504 cpu_relax();
0970d299 1505 /*
e4a52bcb 1506 * Pairs with the smp_wmb() in finish_lock_switch().
0970d299 1507 */
e4a52bcb 1508 smp_rmb();
1da177e4 1509
a8e4f2ea 1510 p->sched_contributes_to_load = !!task_contributes_to_load(p);
e9c84311 1511 p->state = TASK_WAKING;
e7693a36 1512
e4a52bcb 1513 if (p->sched_class->task_waking)
74f8e4b2 1514 p->sched_class->task_waking(p);
efbbd05a 1515
7608dec2 1516 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
f339b9dc
PZ
1517 if (task_cpu(p) != cpu) {
1518 wake_flags |= WF_MIGRATED;
e4a52bcb 1519 set_task_cpu(p, cpu);
f339b9dc 1520 }
1da177e4 1521#endif /* CONFIG_SMP */
1da177e4 1522
c05fbafb
PZ
1523 ttwu_queue(p, cpu);
1524stat:
b84cb5df 1525 ttwu_stat(p, cpu, wake_flags);
1da177e4 1526out:
013fdb80 1527 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1da177e4
LT
1528
1529 return success;
1530}
1531
21aa9af0
TH
1532/**
1533 * try_to_wake_up_local - try to wake up a local task with rq lock held
1534 * @p: the thread to be awakened
1535 *
2acca55e 1536 * Put @p on the run-queue if it's not already there. The caller must
21aa9af0 1537 * ensure that this_rq() is locked, @p is bound to this_rq() and not
2acca55e 1538 * the current task.
21aa9af0
TH
1539 */
1540static void try_to_wake_up_local(struct task_struct *p)
1541{
1542 struct rq *rq = task_rq(p);
21aa9af0 1543
383efcd0
TH
1544 if (WARN_ON_ONCE(rq != this_rq()) ||
1545 WARN_ON_ONCE(p == current))
1546 return;
1547
21aa9af0
TH
1548 lockdep_assert_held(&rq->lock);
1549
2acca55e
PZ
1550 if (!raw_spin_trylock(&p->pi_lock)) {
1551 raw_spin_unlock(&rq->lock);
1552 raw_spin_lock(&p->pi_lock);
1553 raw_spin_lock(&rq->lock);
1554 }
1555
21aa9af0 1556 if (!(p->state & TASK_NORMAL))
2acca55e 1557 goto out;
21aa9af0 1558
fd2f4419 1559 if (!p->on_rq)
d7c01d27
PZ
1560 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
1561
23f41eeb 1562 ttwu_do_wakeup(rq, p, 0);
b84cb5df 1563 ttwu_stat(p, smp_processor_id(), 0);
2acca55e
PZ
1564out:
1565 raw_spin_unlock(&p->pi_lock);
21aa9af0
TH
1566}
1567
50fa610a
DH
1568/**
1569 * wake_up_process - Wake up a specific process
1570 * @p: The process to be woken up.
1571 *
1572 * Attempt to wake up the nominated process and move it to the set of runnable
e69f6186
YB
1573 * processes.
1574 *
1575 * Return: 1 if the process was woken up, 0 if it was already running.
50fa610a
DH
1576 *
1577 * It may be assumed that this function implies a write memory barrier before
1578 * changing the task state if and only if any tasks are woken up.
1579 */
7ad5b3a5 1580int wake_up_process(struct task_struct *p)
1da177e4 1581{
9067ac85
ON
1582 WARN_ON(task_is_stopped_or_traced(p));
1583 return try_to_wake_up(p, TASK_NORMAL, 0);
1da177e4 1584}
1da177e4
LT
1585EXPORT_SYMBOL(wake_up_process);
1586
7ad5b3a5 1587int wake_up_state(struct task_struct *p, unsigned int state)
1da177e4
LT
1588{
1589 return try_to_wake_up(p, state, 0);
1590}
1591
1da177e4
LT
1592/*
1593 * Perform scheduler related setup for a newly forked process p.
1594 * p is forked by current.
dd41f596
IM
1595 *
1596 * __sched_fork() is basic setup used by init_idle() too:
1597 */
1598static void __sched_fork(struct task_struct *p)
1599{
fd2f4419
PZ
1600 p->on_rq = 0;
1601
1602 p->se.on_rq = 0;
dd41f596
IM
1603 p->se.exec_start = 0;
1604 p->se.sum_exec_runtime = 0;
f6cf891c 1605 p->se.prev_sum_exec_runtime = 0;
6c594c21 1606 p->se.nr_migrations = 0;
da7a735e 1607 p->se.vruntime = 0;
fd2f4419 1608 INIT_LIST_HEAD(&p->se.group_node);
6cfb0d5d
IM
1609
1610#ifdef CONFIG_SCHEDSTATS
41acab88 1611 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
6cfb0d5d 1612#endif
476d139c 1613
fa717060 1614 INIT_LIST_HEAD(&p->rt.run_list);
476d139c 1615
e107be36
AK
1616#ifdef CONFIG_PREEMPT_NOTIFIERS
1617 INIT_HLIST_HEAD(&p->preempt_notifiers);
1618#endif
cbee9f88
PZ
1619
1620#ifdef CONFIG_NUMA_BALANCING
1621 if (p->mm && atomic_read(&p->mm->mm_users) == 1) {
1622 p->mm->numa_next_scan = jiffies;
b8593bfd 1623 p->mm->numa_next_reset = jiffies;
cbee9f88
PZ
1624 p->mm->numa_scan_seq = 0;
1625 }
1626
1627 p->node_stamp = 0ULL;
1628 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0;
1629 p->numa_migrate_seq = p->mm ? p->mm->numa_scan_seq - 1 : 0;
4b96a29b 1630 p->numa_scan_period = sysctl_numa_balancing_scan_delay;
cbee9f88
PZ
1631 p->numa_work.next = &p->numa_work;
1632#endif /* CONFIG_NUMA_BALANCING */
dd41f596
IM
1633}
1634
1a687c2e 1635#ifdef CONFIG_NUMA_BALANCING
3105b86a 1636#ifdef CONFIG_SCHED_DEBUG
1a687c2e
MG
1637void set_numabalancing_state(bool enabled)
1638{
1639 if (enabled)
1640 sched_feat_set("NUMA");
1641 else
1642 sched_feat_set("NO_NUMA");
1643}
3105b86a
MG
1644#else
1645__read_mostly bool numabalancing_enabled;
1646
1647void set_numabalancing_state(bool enabled)
1648{
1649 numabalancing_enabled = enabled;
dd41f596 1650}
3105b86a 1651#endif /* CONFIG_SCHED_DEBUG */
1a687c2e 1652#endif /* CONFIG_NUMA_BALANCING */
dd41f596
IM
1653
1654/*
1655 * fork()/clone()-time setup:
1656 */
3e51e3ed 1657void sched_fork(struct task_struct *p)
dd41f596 1658{
0122ec5b 1659 unsigned long flags;
dd41f596
IM
1660 int cpu = get_cpu();
1661
1662 __sched_fork(p);
06b83b5f 1663 /*
0017d735 1664 * We mark the process as running here. This guarantees that
06b83b5f
PZ
1665 * nobody will actually run it, and a signal or other external
1666 * event cannot wake it up and insert it on the runqueue either.
1667 */
0017d735 1668 p->state = TASK_RUNNING;
dd41f596 1669
c350a04e
MG
1670 /*
1671 * Make sure we do not leak PI boosting priority to the child.
1672 */
1673 p->prio = current->normal_prio;
1674
b9dc29e7
MG
1675 /*
1676 * Revert to default priority/policy on fork if requested.
1677 */
1678 if (unlikely(p->sched_reset_on_fork)) {
c350a04e 1679 if (task_has_rt_policy(p)) {
b9dc29e7 1680 p->policy = SCHED_NORMAL;
6c697bdf 1681 p->static_prio = NICE_TO_PRIO(0);
c350a04e
MG
1682 p->rt_priority = 0;
1683 } else if (PRIO_TO_NICE(p->static_prio) < 0)
1684 p->static_prio = NICE_TO_PRIO(0);
1685
1686 p->prio = p->normal_prio = __normal_prio(p);
1687 set_load_weight(p);
6c697bdf 1688
b9dc29e7
MG
1689 /*
1690 * We don't need the reset flag anymore after the fork. It has
1691 * fulfilled its duty:
1692 */
1693 p->sched_reset_on_fork = 0;
1694 }
ca94c442 1695
2ddbf952
HS
1696 if (!rt_prio(p->prio))
1697 p->sched_class = &fair_sched_class;
b29739f9 1698
cd29fe6f
PZ
1699 if (p->sched_class->task_fork)
1700 p->sched_class->task_fork(p);
1701
86951599
PZ
1702 /*
1703 * The child is not yet in the pid-hash so no cgroup attach races,
1704 * and the cgroup is pinned to this child due to cgroup_fork()
1705 * is ran before sched_fork().
1706 *
1707 * Silence PROVE_RCU.
1708 */
0122ec5b 1709 raw_spin_lock_irqsave(&p->pi_lock, flags);
5f3edc1b 1710 set_task_cpu(p, cpu);
0122ec5b 1711 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
5f3edc1b 1712
52f17b6c 1713#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
dd41f596 1714 if (likely(sched_info_on()))
52f17b6c 1715 memset(&p->sched_info, 0, sizeof(p->sched_info));
1da177e4 1716#endif
3ca7a440
PZ
1717#if defined(CONFIG_SMP)
1718 p->on_cpu = 0;
4866cde0 1719#endif
bdd4e85d 1720#ifdef CONFIG_PREEMPT_COUNT
4866cde0 1721 /* Want to start with kernel preemption disabled. */
a1261f54 1722 task_thread_info(p)->preempt_count = 1;
1da177e4 1723#endif
806c09a7 1724#ifdef CONFIG_SMP
917b627d 1725 plist_node_init(&p->pushable_tasks, MAX_PRIO);
806c09a7 1726#endif
917b627d 1727
476d139c 1728 put_cpu();
1da177e4
LT
1729}
1730
1731/*
1732 * wake_up_new_task - wake up a newly created task for the first time.
1733 *
1734 * This function will do some initial scheduler statistics housekeeping
1735 * that must be done for every newly created context, then puts the task
1736 * on the runqueue and wakes it.
1737 */
3e51e3ed 1738void wake_up_new_task(struct task_struct *p)
1da177e4
LT
1739{
1740 unsigned long flags;
dd41f596 1741 struct rq *rq;
fabf318e 1742
ab2515c4 1743 raw_spin_lock_irqsave(&p->pi_lock, flags);
fabf318e
PZ
1744#ifdef CONFIG_SMP
1745 /*
1746 * Fork balancing, do it here and not earlier because:
1747 * - cpus_allowed can change in the fork path
1748 * - any previously selected cpu might disappear through hotplug
fabf318e 1749 */
ab2515c4 1750 set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0));
0017d735
PZ
1751#endif
1752
a75cdaa9
AS
1753 /* Initialize new task's runnable average */
1754 init_task_runnable_average(p);
ab2515c4 1755 rq = __task_rq_lock(p);
cd29fe6f 1756 activate_task(rq, p, 0);
fd2f4419 1757 p->on_rq = 1;
89363381 1758 trace_sched_wakeup_new(p, true);
a7558e01 1759 check_preempt_curr(rq, p, WF_FORK);
9a897c5a 1760#ifdef CONFIG_SMP
efbbd05a
PZ
1761 if (p->sched_class->task_woken)
1762 p->sched_class->task_woken(rq, p);
9a897c5a 1763#endif
0122ec5b 1764 task_rq_unlock(rq, p, &flags);
1da177e4
LT
1765}
1766
e107be36
AK
1767#ifdef CONFIG_PREEMPT_NOTIFIERS
1768
1769/**
80dd99b3 1770 * preempt_notifier_register - tell me when current is being preempted & rescheduled
421cee29 1771 * @notifier: notifier struct to register
e107be36
AK
1772 */
1773void preempt_notifier_register(struct preempt_notifier *notifier)
1774{
1775 hlist_add_head(&notifier->link, &current->preempt_notifiers);
1776}
1777EXPORT_SYMBOL_GPL(preempt_notifier_register);
1778
1779/**
1780 * preempt_notifier_unregister - no longer interested in preemption notifications
421cee29 1781 * @notifier: notifier struct to unregister
e107be36
AK
1782 *
1783 * This is safe to call from within a preemption notifier.
1784 */
1785void preempt_notifier_unregister(struct preempt_notifier *notifier)
1786{
1787 hlist_del(&notifier->link);
1788}
1789EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
1790
1791static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1792{
1793 struct preempt_notifier *notifier;
e107be36 1794
b67bfe0d 1795 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
e107be36
AK
1796 notifier->ops->sched_in(notifier, raw_smp_processor_id());
1797}
1798
1799static void
1800fire_sched_out_preempt_notifiers(struct task_struct *curr,
1801 struct task_struct *next)
1802{
1803 struct preempt_notifier *notifier;
e107be36 1804
b67bfe0d 1805 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
e107be36
AK
1806 notifier->ops->sched_out(notifier, next);
1807}
1808
6d6bc0ad 1809#else /* !CONFIG_PREEMPT_NOTIFIERS */
e107be36
AK
1810
1811static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1812{
1813}
1814
1815static void
1816fire_sched_out_preempt_notifiers(struct task_struct *curr,
1817 struct task_struct *next)
1818{
1819}
1820
6d6bc0ad 1821#endif /* CONFIG_PREEMPT_NOTIFIERS */
e107be36 1822
4866cde0
NP
1823/**
1824 * prepare_task_switch - prepare to switch tasks
1825 * @rq: the runqueue preparing to switch
421cee29 1826 * @prev: the current task that is being switched out
4866cde0
NP
1827 * @next: the task we are going to switch to.
1828 *
1829 * This is called with the rq lock held and interrupts off. It must
1830 * be paired with a subsequent finish_task_switch after the context
1831 * switch.
1832 *
1833 * prepare_task_switch sets up locking and calls architecture specific
1834 * hooks.
1835 */
e107be36
AK
1836static inline void
1837prepare_task_switch(struct rq *rq, struct task_struct *prev,
1838 struct task_struct *next)
4866cde0 1839{
895dd92c 1840 trace_sched_switch(prev, next);
fe4b04fa
PZ
1841 sched_info_switch(prev, next);
1842 perf_event_task_sched_out(prev, next);
e107be36 1843 fire_sched_out_preempt_notifiers(prev, next);
4866cde0
NP
1844 prepare_lock_switch(rq, next);
1845 prepare_arch_switch(next);
1846}
1847
1da177e4
LT
1848/**
1849 * finish_task_switch - clean up after a task-switch
344babaa 1850 * @rq: runqueue associated with task-switch
1da177e4
LT
1851 * @prev: the thread we just switched away from.
1852 *
4866cde0
NP
1853 * finish_task_switch must be called after the context switch, paired
1854 * with a prepare_task_switch call before the context switch.
1855 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1856 * and do any other architecture-specific cleanup actions.
1da177e4
LT
1857 *
1858 * Note that we may have delayed dropping an mm in context_switch(). If
41a2d6cf 1859 * so, we finish that here outside of the runqueue lock. (Doing it
1da177e4
LT
1860 * with the lock held can cause deadlocks; see schedule() for
1861 * details.)
1862 */
a9957449 1863static void finish_task_switch(struct rq *rq, struct task_struct *prev)
1da177e4
LT
1864 __releases(rq->lock)
1865{
1da177e4 1866 struct mm_struct *mm = rq->prev_mm;
55a101f8 1867 long prev_state;
1da177e4
LT
1868
1869 rq->prev_mm = NULL;
1870
1871 /*
1872 * A task struct has one reference for the use as "current".
c394cc9f 1873 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
55a101f8
ON
1874 * schedule one last time. The schedule call will never return, and
1875 * the scheduled task must drop that reference.
c394cc9f 1876 * The test for TASK_DEAD must occur while the runqueue locks are
1da177e4
LT
1877 * still held, otherwise prev could be scheduled on another cpu, die
1878 * there before we look at prev->state, and then the reference would
1879 * be dropped twice.
1880 * Manfred Spraul <manfred@colorfullife.com>
1881 */
55a101f8 1882 prev_state = prev->state;
bf9fae9f 1883 vtime_task_switch(prev);
4866cde0 1884 finish_arch_switch(prev);
a8d757ef 1885 perf_event_task_sched_in(prev, current);
4866cde0 1886 finish_lock_switch(rq, prev);
01f23e16 1887 finish_arch_post_lock_switch();
e8fa1362 1888
e107be36 1889 fire_sched_in_preempt_notifiers(current);
1da177e4
LT
1890 if (mm)
1891 mmdrop(mm);
c394cc9f 1892 if (unlikely(prev_state == TASK_DEAD)) {
c6fd91f0 1893 /*
1894 * Remove function-return probe instances associated with this
1895 * task and put them back on the free list.
9761eea8 1896 */
c6fd91f0 1897 kprobe_flush_task(prev);
1da177e4 1898 put_task_struct(prev);
c6fd91f0 1899 }
99e5ada9
FW
1900
1901 tick_nohz_task_switch(current);
1da177e4
LT
1902}
1903
3f029d3c
GH
1904#ifdef CONFIG_SMP
1905
1906/* assumes rq->lock is held */
1907static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
1908{
1909 if (prev->sched_class->pre_schedule)
1910 prev->sched_class->pre_schedule(rq, prev);
1911}
1912
1913/* rq->lock is NOT held, but preemption is disabled */
1914static inline void post_schedule(struct rq *rq)
1915{
1916 if (rq->post_schedule) {
1917 unsigned long flags;
1918
05fa785c 1919 raw_spin_lock_irqsave(&rq->lock, flags);
3f029d3c
GH
1920 if (rq->curr->sched_class->post_schedule)
1921 rq->curr->sched_class->post_schedule(rq);
05fa785c 1922 raw_spin_unlock_irqrestore(&rq->lock, flags);
3f029d3c
GH
1923
1924 rq->post_schedule = 0;
1925 }
1926}
1927
1928#else
da19ab51 1929
3f029d3c
GH
1930static inline void pre_schedule(struct rq *rq, struct task_struct *p)
1931{
1932}
1933
1934static inline void post_schedule(struct rq *rq)
1935{
1da177e4
LT
1936}
1937
3f029d3c
GH
1938#endif
1939
1da177e4
LT
1940/**
1941 * schedule_tail - first thing a freshly forked thread must call.
1942 * @prev: the thread we just switched away from.
1943 */
36c8b586 1944asmlinkage void schedule_tail(struct task_struct *prev)
1da177e4
LT
1945 __releases(rq->lock)
1946{
70b97a7f
IM
1947 struct rq *rq = this_rq();
1948
4866cde0 1949 finish_task_switch(rq, prev);
da19ab51 1950
3f029d3c
GH
1951 /*
1952 * FIXME: do we need to worry about rq being invalidated by the
1953 * task_switch?
1954 */
1955 post_schedule(rq);
70b97a7f 1956
4866cde0
NP
1957#ifdef __ARCH_WANT_UNLOCKED_CTXSW
1958 /* In this case, finish_task_switch does not reenable preemption */
1959 preempt_enable();
1960#endif
1da177e4 1961 if (current->set_child_tid)
b488893a 1962 put_user(task_pid_vnr(current), current->set_child_tid);
1da177e4
LT
1963}
1964
1965/*
1966 * context_switch - switch to the new MM and the new
1967 * thread's register state.
1968 */
dd41f596 1969static inline void
70b97a7f 1970context_switch(struct rq *rq, struct task_struct *prev,
36c8b586 1971 struct task_struct *next)
1da177e4 1972{
dd41f596 1973 struct mm_struct *mm, *oldmm;
1da177e4 1974
e107be36 1975 prepare_task_switch(rq, prev, next);
fe4b04fa 1976
dd41f596
IM
1977 mm = next->mm;
1978 oldmm = prev->active_mm;
9226d125
ZA
1979 /*
1980 * For paravirt, this is coupled with an exit in switch_to to
1981 * combine the page table reload and the switch backend into
1982 * one hypercall.
1983 */
224101ed 1984 arch_start_context_switch(prev);
9226d125 1985
31915ab4 1986 if (!mm) {
1da177e4
LT
1987 next->active_mm = oldmm;
1988 atomic_inc(&oldmm->mm_count);
1989 enter_lazy_tlb(oldmm, next);
1990 } else
1991 switch_mm(oldmm, mm, next);
1992
31915ab4 1993 if (!prev->mm) {
1da177e4 1994 prev->active_mm = NULL;
1da177e4
LT
1995 rq->prev_mm = oldmm;
1996 }
3a5f5e48
IM
1997 /*
1998 * Since the runqueue lock will be released by the next
1999 * task (which is an invalid locking op but in the case
2000 * of the scheduler it's an obvious special-case), so we
2001 * do an early lockdep release here:
2002 */
2003#ifndef __ARCH_WANT_UNLOCKED_CTXSW
8a25d5de 2004 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
3a5f5e48 2005#endif
1da177e4 2006
91d1aa43 2007 context_tracking_task_switch(prev, next);
1da177e4
LT
2008 /* Here we just switch the register state and the stack. */
2009 switch_to(prev, next, prev);
2010
dd41f596
IM
2011 barrier();
2012 /*
2013 * this_rq must be evaluated again because prev may have moved
2014 * CPUs since it called schedule(), thus the 'rq' on its stack
2015 * frame will be invalid.
2016 */
2017 finish_task_switch(this_rq(), prev);
1da177e4
LT
2018}
2019
2020/*
1c3e8264 2021 * nr_running and nr_context_switches:
1da177e4
LT
2022 *
2023 * externally visible scheduler statistics: current number of runnable
1c3e8264 2024 * threads, total number of context switches performed since bootup.
1da177e4
LT
2025 */
2026unsigned long nr_running(void)
2027{
2028 unsigned long i, sum = 0;
2029
2030 for_each_online_cpu(i)
2031 sum += cpu_rq(i)->nr_running;
2032
2033 return sum;
f711f609 2034}
1da177e4 2035
1da177e4 2036unsigned long long nr_context_switches(void)
46cb4b7c 2037{
cc94abfc
SR
2038 int i;
2039 unsigned long long sum = 0;
46cb4b7c 2040
0a945022 2041 for_each_possible_cpu(i)
1da177e4 2042 sum += cpu_rq(i)->nr_switches;
46cb4b7c 2043
1da177e4
LT
2044 return sum;
2045}
483b4ee6 2046
1da177e4
LT
2047unsigned long nr_iowait(void)
2048{
2049 unsigned long i, sum = 0;
483b4ee6 2050
0a945022 2051 for_each_possible_cpu(i)
1da177e4 2052 sum += atomic_read(&cpu_rq(i)->nr_iowait);
46cb4b7c 2053
1da177e4
LT
2054 return sum;
2055}
483b4ee6 2056
8c215bd3 2057unsigned long nr_iowait_cpu(int cpu)
69d25870 2058{
8c215bd3 2059 struct rq *this = cpu_rq(cpu);
69d25870
AV
2060 return atomic_read(&this->nr_iowait);
2061}
46cb4b7c 2062
dd41f596 2063#ifdef CONFIG_SMP
8a0be9ef 2064
46cb4b7c 2065/*
38022906
PZ
2066 * sched_exec - execve() is a valuable balancing opportunity, because at
2067 * this point the task has the smallest effective memory and cache footprint.
46cb4b7c 2068 */
38022906 2069void sched_exec(void)
46cb4b7c 2070{
38022906 2071 struct task_struct *p = current;
1da177e4 2072 unsigned long flags;
0017d735 2073 int dest_cpu;
46cb4b7c 2074
8f42ced9 2075 raw_spin_lock_irqsave(&p->pi_lock, flags);
7608dec2 2076 dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0);
0017d735
PZ
2077 if (dest_cpu == smp_processor_id())
2078 goto unlock;
38022906 2079
8f42ced9 2080 if (likely(cpu_active(dest_cpu))) {
969c7921 2081 struct migration_arg arg = { p, dest_cpu };
46cb4b7c 2082
8f42ced9
PZ
2083 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2084 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
1da177e4
LT
2085 return;
2086 }
0017d735 2087unlock:
8f42ced9 2088 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1da177e4 2089}
dd41f596 2090
1da177e4
LT
2091#endif
2092
1da177e4 2093DEFINE_PER_CPU(struct kernel_stat, kstat);
3292beb3 2094DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
1da177e4
LT
2095
2096EXPORT_PER_CPU_SYMBOL(kstat);
3292beb3 2097EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
1da177e4
LT
2098
2099/*
c5f8d995 2100 * Return any ns on the sched_clock that have not yet been accounted in
f06febc9 2101 * @p in case that task is currently running.
c5f8d995
HS
2102 *
2103 * Called with task_rq_lock() held on @rq.
1da177e4 2104 */
c5f8d995
HS
2105static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
2106{
2107 u64 ns = 0;
2108
2109 if (task_current(rq, p)) {
2110 update_rq_clock(rq);
78becc27 2111 ns = rq_clock_task(rq) - p->se.exec_start;
c5f8d995
HS
2112 if ((s64)ns < 0)
2113 ns = 0;
2114 }
2115
2116 return ns;
2117}
2118
bb34d92f 2119unsigned long long task_delta_exec(struct task_struct *p)
1da177e4 2120{
1da177e4 2121 unsigned long flags;
41b86e9c 2122 struct rq *rq;
bb34d92f 2123 u64 ns = 0;
48f24c4d 2124
41b86e9c 2125 rq = task_rq_lock(p, &flags);
c5f8d995 2126 ns = do_task_delta_exec(p, rq);
0122ec5b 2127 task_rq_unlock(rq, p, &flags);
1508487e 2128
c5f8d995
HS
2129 return ns;
2130}
f06febc9 2131
c5f8d995
HS
2132/*
2133 * Return accounted runtime for the task.
2134 * In case the task is currently running, return the runtime plus current's
2135 * pending runtime that have not been accounted yet.
2136 */
2137unsigned long long task_sched_runtime(struct task_struct *p)
2138{
2139 unsigned long flags;
2140 struct rq *rq;
2141 u64 ns = 0;
2142
2143 rq = task_rq_lock(p, &flags);
2144 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
0122ec5b 2145 task_rq_unlock(rq, p, &flags);
c5f8d995
HS
2146
2147 return ns;
2148}
48f24c4d 2149
7835b98b
CL
2150/*
2151 * This function gets called by the timer code, with HZ frequency.
2152 * We call it with interrupts disabled.
7835b98b
CL
2153 */
2154void scheduler_tick(void)
2155{
7835b98b
CL
2156 int cpu = smp_processor_id();
2157 struct rq *rq = cpu_rq(cpu);
dd41f596 2158 struct task_struct *curr = rq->curr;
3e51f33f
PZ
2159
2160 sched_clock_tick();
dd41f596 2161
05fa785c 2162 raw_spin_lock(&rq->lock);
3e51f33f 2163 update_rq_clock(rq);
fa85ae24 2164 curr->sched_class->task_tick(rq, curr, 0);
83dfd523 2165 update_cpu_load_active(rq);
05fa785c 2166 raw_spin_unlock(&rq->lock);
7835b98b 2167
e9d2b064 2168 perf_event_task_tick();
e220d2dc 2169
e418e1c2 2170#ifdef CONFIG_SMP
6eb57e0d 2171 rq->idle_balance = idle_cpu(cpu);
dd41f596 2172 trigger_load_balance(rq, cpu);
e418e1c2 2173#endif
265f22a9 2174 rq_last_tick_reset(rq);
1da177e4
LT
2175}
2176
265f22a9
FW
2177#ifdef CONFIG_NO_HZ_FULL
2178/**
2179 * scheduler_tick_max_deferment
2180 *
2181 * Keep at least one tick per second when a single
2182 * active task is running because the scheduler doesn't
2183 * yet completely support full dynticks environment.
2184 *
2185 * This makes sure that uptime, CFS vruntime, load
2186 * balancing, etc... continue to move forward, even
2187 * with a very low granularity.
e69f6186
YB
2188 *
2189 * Return: Maximum deferment in nanoseconds.
265f22a9
FW
2190 */
2191u64 scheduler_tick_max_deferment(void)
2192{
2193 struct rq *rq = this_rq();
2194 unsigned long next, now = ACCESS_ONCE(jiffies);
2195
2196 next = rq->last_sched_tick + HZ;
2197
2198 if (time_before_eq(next, now))
2199 return 0;
2200
2201 return jiffies_to_usecs(next - now) * NSEC_PER_USEC;
1da177e4 2202}
265f22a9 2203#endif
1da177e4 2204
132380a0 2205notrace unsigned long get_parent_ip(unsigned long addr)
6cd8a4bb
SR
2206{
2207 if (in_lock_functions(addr)) {
2208 addr = CALLER_ADDR2;
2209 if (in_lock_functions(addr))
2210 addr = CALLER_ADDR3;
2211 }
2212 return addr;
2213}
1da177e4 2214
7e49fcce
SR
2215#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2216 defined(CONFIG_PREEMPT_TRACER))
2217
43627582 2218void __kprobes add_preempt_count(int val)
1da177e4 2219{
6cd8a4bb 2220#ifdef CONFIG_DEBUG_PREEMPT
1da177e4
LT
2221 /*
2222 * Underflow?
2223 */
9a11b49a
IM
2224 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2225 return;
6cd8a4bb 2226#endif
1da177e4 2227 preempt_count() += val;
6cd8a4bb 2228#ifdef CONFIG_DEBUG_PREEMPT
1da177e4
LT
2229 /*
2230 * Spinlock count overflowing soon?
2231 */
33859f7f
MOS
2232 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
2233 PREEMPT_MASK - 10);
6cd8a4bb
SR
2234#endif
2235 if (preempt_count() == val)
2236 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
1da177e4
LT
2237}
2238EXPORT_SYMBOL(add_preempt_count);
2239
43627582 2240void __kprobes sub_preempt_count(int val)
1da177e4 2241{
6cd8a4bb 2242#ifdef CONFIG_DEBUG_PREEMPT
1da177e4
LT
2243 /*
2244 * Underflow?
2245 */
01e3eb82 2246 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
9a11b49a 2247 return;
1da177e4
LT
2248 /*
2249 * Is the spinlock portion underflowing?
2250 */
9a11b49a
IM
2251 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
2252 !(preempt_count() & PREEMPT_MASK)))
2253 return;
6cd8a4bb 2254#endif
9a11b49a 2255
6cd8a4bb
SR
2256 if (preempt_count() == val)
2257 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
1da177e4
LT
2258 preempt_count() -= val;
2259}
2260EXPORT_SYMBOL(sub_preempt_count);
2261
2262#endif
2263
2264/*
dd41f596 2265 * Print scheduling while atomic bug:
1da177e4 2266 */
dd41f596 2267static noinline void __schedule_bug(struct task_struct *prev)
1da177e4 2268{
664dfa65
DJ
2269 if (oops_in_progress)
2270 return;
2271
3df0fc5b
PZ
2272 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
2273 prev->comm, prev->pid, preempt_count());
838225b4 2274
dd41f596 2275 debug_show_held_locks(prev);
e21f5b15 2276 print_modules();
dd41f596
IM
2277 if (irqs_disabled())
2278 print_irqtrace_events(prev);
6135fc1e 2279 dump_stack();
373d4d09 2280 add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
dd41f596 2281}
1da177e4 2282
dd41f596
IM
2283/*
2284 * Various schedule()-time debugging checks and statistics:
2285 */
2286static inline void schedule_debug(struct task_struct *prev)
2287{
1da177e4 2288 /*
41a2d6cf 2289 * Test if we are atomic. Since do_exit() needs to call into
1da177e4
LT
2290 * schedule() atomically, we ignore that path for now.
2291 * Otherwise, whine if we are scheduling when we should not be.
2292 */
3f33a7ce 2293 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
dd41f596 2294 __schedule_bug(prev);
b3fbab05 2295 rcu_sleep_check();
dd41f596 2296
1da177e4
LT
2297 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
2298
2d72376b 2299 schedstat_inc(this_rq(), sched_count);
dd41f596
IM
2300}
2301
6cecd084 2302static void put_prev_task(struct rq *rq, struct task_struct *prev)
df1c99d4 2303{
61eadef6 2304 if (prev->on_rq || rq->skip_clock_update < 0)
a64692a3 2305 update_rq_clock(rq);
6cecd084 2306 prev->sched_class->put_prev_task(rq, prev);
df1c99d4
MG
2307}
2308
dd41f596
IM
2309/*
2310 * Pick up the highest-prio task:
2311 */
2312static inline struct task_struct *
b67802ea 2313pick_next_task(struct rq *rq)
dd41f596 2314{
5522d5d5 2315 const struct sched_class *class;
dd41f596 2316 struct task_struct *p;
1da177e4
LT
2317
2318 /*
dd41f596
IM
2319 * Optimization: we know that if all tasks are in
2320 * the fair class we can call that function directly:
1da177e4 2321 */
953bfcd1 2322 if (likely(rq->nr_running == rq->cfs.h_nr_running)) {
fb8d4724 2323 p = fair_sched_class.pick_next_task(rq);
dd41f596
IM
2324 if (likely(p))
2325 return p;
1da177e4
LT
2326 }
2327
34f971f6 2328 for_each_class(class) {
fb8d4724 2329 p = class->pick_next_task(rq);
dd41f596
IM
2330 if (p)
2331 return p;
dd41f596 2332 }
34f971f6
PZ
2333
2334 BUG(); /* the idle class will always have a runnable task */
dd41f596 2335}
1da177e4 2336
dd41f596 2337/*
c259e01a 2338 * __schedule() is the main scheduler function.
edde96ea
PE
2339 *
2340 * The main means of driving the scheduler and thus entering this function are:
2341 *
2342 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2343 *
2344 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2345 * paths. For example, see arch/x86/entry_64.S.
2346 *
2347 * To drive preemption between tasks, the scheduler sets the flag in timer
2348 * interrupt handler scheduler_tick().
2349 *
2350 * 3. Wakeups don't really cause entry into schedule(). They add a
2351 * task to the run-queue and that's it.
2352 *
2353 * Now, if the new task added to the run-queue preempts the current
2354 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2355 * called on the nearest possible occasion:
2356 *
2357 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2358 *
2359 * - in syscall or exception context, at the next outmost
2360 * preempt_enable(). (this might be as soon as the wake_up()'s
2361 * spin_unlock()!)
2362 *
2363 * - in IRQ context, return from interrupt-handler to
2364 * preemptible context
2365 *
2366 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2367 * then at the next:
2368 *
2369 * - cond_resched() call
2370 * - explicit schedule() call
2371 * - return from syscall or exception to user-space
2372 * - return from interrupt-handler to user-space
dd41f596 2373 */
c259e01a 2374static void __sched __schedule(void)
dd41f596
IM
2375{
2376 struct task_struct *prev, *next;
67ca7bde 2377 unsigned long *switch_count;
dd41f596 2378 struct rq *rq;
31656519 2379 int cpu;
dd41f596 2380
ff743345
PZ
2381need_resched:
2382 preempt_disable();
dd41f596
IM
2383 cpu = smp_processor_id();
2384 rq = cpu_rq(cpu);
25502a6c 2385 rcu_note_context_switch(cpu);
dd41f596 2386 prev = rq->curr;
dd41f596 2387
dd41f596 2388 schedule_debug(prev);
1da177e4 2389
31656519 2390 if (sched_feat(HRTICK))
f333fdc9 2391 hrtick_clear(rq);
8f4d37ec 2392
e0acd0a6
ON
2393 /*
2394 * Make sure that signal_pending_state()->signal_pending() below
2395 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2396 * done by the caller to avoid the race with signal_wake_up().
2397 */
2398 smp_mb__before_spinlock();
05fa785c 2399 raw_spin_lock_irq(&rq->lock);
1da177e4 2400
246d86b5 2401 switch_count = &prev->nivcsw;
1da177e4 2402 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
21aa9af0 2403 if (unlikely(signal_pending_state(prev->state, prev))) {
1da177e4 2404 prev->state = TASK_RUNNING;
21aa9af0 2405 } else {
2acca55e
PZ
2406 deactivate_task(rq, prev, DEQUEUE_SLEEP);
2407 prev->on_rq = 0;
2408
21aa9af0 2409 /*
2acca55e
PZ
2410 * If a worker went to sleep, notify and ask workqueue
2411 * whether it wants to wake up a task to maintain
2412 * concurrency.
21aa9af0
TH
2413 */
2414 if (prev->flags & PF_WQ_WORKER) {
2415 struct task_struct *to_wakeup;
2416
2417 to_wakeup = wq_worker_sleeping(prev, cpu);
2418 if (to_wakeup)
2419 try_to_wake_up_local(to_wakeup);
2420 }
21aa9af0 2421 }
dd41f596 2422 switch_count = &prev->nvcsw;
1da177e4
LT
2423 }
2424
3f029d3c 2425 pre_schedule(rq, prev);
f65eda4f 2426
dd41f596 2427 if (unlikely(!rq->nr_running))
1da177e4 2428 idle_balance(cpu, rq);
1da177e4 2429
df1c99d4 2430 put_prev_task(rq, prev);
b67802ea 2431 next = pick_next_task(rq);
f26f9aff
MG
2432 clear_tsk_need_resched(prev);
2433 rq->skip_clock_update = 0;
1da177e4 2434
1da177e4 2435 if (likely(prev != next)) {
1da177e4
LT
2436 rq->nr_switches++;
2437 rq->curr = next;
2438 ++*switch_count;
2439
dd41f596 2440 context_switch(rq, prev, next); /* unlocks the rq */
8f4d37ec 2441 /*
246d86b5
ON
2442 * The context switch have flipped the stack from under us
2443 * and restored the local variables which were saved when
2444 * this task called schedule() in the past. prev == current
2445 * is still correct, but it can be moved to another cpu/rq.
8f4d37ec
PZ
2446 */
2447 cpu = smp_processor_id();
2448 rq = cpu_rq(cpu);
1da177e4 2449 } else
05fa785c 2450 raw_spin_unlock_irq(&rq->lock);
1da177e4 2451
3f029d3c 2452 post_schedule(rq);
1da177e4 2453
ba74c144 2454 sched_preempt_enable_no_resched();
ff743345 2455 if (need_resched())
1da177e4
LT
2456 goto need_resched;
2457}
c259e01a 2458
9c40cef2
TG
2459static inline void sched_submit_work(struct task_struct *tsk)
2460{
3c7d5184 2461 if (!tsk->state || tsk_is_pi_blocked(tsk))
9c40cef2
TG
2462 return;
2463 /*
2464 * If we are going to sleep and we have plugged IO queued,
2465 * make sure to submit it to avoid deadlocks.
2466 */
2467 if (blk_needs_flush_plug(tsk))
2468 blk_schedule_flush_plug(tsk);
2469}
2470
6ebbe7a0 2471asmlinkage void __sched schedule(void)
c259e01a 2472{
9c40cef2
TG
2473 struct task_struct *tsk = current;
2474
2475 sched_submit_work(tsk);
c259e01a
TG
2476 __schedule();
2477}
1da177e4
LT
2478EXPORT_SYMBOL(schedule);
2479
91d1aa43 2480#ifdef CONFIG_CONTEXT_TRACKING
20ab65e3
FW
2481asmlinkage void __sched schedule_user(void)
2482{
2483 /*
2484 * If we come here after a random call to set_need_resched(),
2485 * or we have been woken up remotely but the IPI has not yet arrived,
2486 * we haven't yet exited the RCU idle mode. Do it here manually until
2487 * we find a better solution.
2488 */
91d1aa43 2489 user_exit();
20ab65e3 2490 schedule();
91d1aa43 2491 user_enter();
20ab65e3
FW
2492}
2493#endif
2494
c5491ea7
TG
2495/**
2496 * schedule_preempt_disabled - called with preemption disabled
2497 *
2498 * Returns with preemption disabled. Note: preempt_count must be 1
2499 */
2500void __sched schedule_preempt_disabled(void)
2501{
ba74c144 2502 sched_preempt_enable_no_resched();
c5491ea7
TG
2503 schedule();
2504 preempt_disable();
2505}
2506
1da177e4
LT
2507#ifdef CONFIG_PREEMPT
2508/*
2ed6e34f 2509 * this is the entry point to schedule() from in-kernel preemption
41a2d6cf 2510 * off of preempt_enable. Kernel preemptions off return from interrupt
1da177e4
LT
2511 * occur there and call schedule directly.
2512 */
d1f74e20 2513asmlinkage void __sched notrace preempt_schedule(void)
1da177e4 2514{
1da177e4
LT
2515 /*
2516 * If there is a non-zero preempt_count or interrupts are disabled,
41a2d6cf 2517 * we do not want to preempt the current task. Just return..
1da177e4 2518 */
fbb00b56 2519 if (likely(!preemptible()))
1da177e4
LT
2520 return;
2521
3a5c359a 2522 do {
d1f74e20 2523 add_preempt_count_notrace(PREEMPT_ACTIVE);
c259e01a 2524 __schedule();
d1f74e20 2525 sub_preempt_count_notrace(PREEMPT_ACTIVE);
1da177e4 2526
3a5c359a
AK
2527 /*
2528 * Check again in case we missed a preemption opportunity
2529 * between schedule and now.
2530 */
2531 barrier();
5ed0cec0 2532 } while (need_resched());
1da177e4 2533}
1da177e4
LT
2534EXPORT_SYMBOL(preempt_schedule);
2535
2536/*
2ed6e34f 2537 * this is the entry point to schedule() from kernel preemption
1da177e4
LT
2538 * off of irq context.
2539 * Note, that this is called and return with irqs disabled. This will
2540 * protect us against recursive calling from irq.
2541 */
2542asmlinkage void __sched preempt_schedule_irq(void)
2543{
2544 struct thread_info *ti = current_thread_info();
b22366cd 2545 enum ctx_state prev_state;
6478d880 2546
2ed6e34f 2547 /* Catch callers which need to be fixed */
1da177e4
LT
2548 BUG_ON(ti->preempt_count || !irqs_disabled());
2549
b22366cd
FW
2550 prev_state = exception_enter();
2551
3a5c359a
AK
2552 do {
2553 add_preempt_count(PREEMPT_ACTIVE);
3a5c359a 2554 local_irq_enable();
c259e01a 2555 __schedule();
3a5c359a 2556 local_irq_disable();
3a5c359a 2557 sub_preempt_count(PREEMPT_ACTIVE);
1da177e4 2558
3a5c359a
AK
2559 /*
2560 * Check again in case we missed a preemption opportunity
2561 * between schedule and now.
2562 */
2563 barrier();
5ed0cec0 2564 } while (need_resched());
b22366cd
FW
2565
2566 exception_exit(prev_state);
1da177e4
LT
2567}
2568
2569#endif /* CONFIG_PREEMPT */
2570
63859d4f 2571int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
95cdf3b7 2572 void *key)
1da177e4 2573{
63859d4f 2574 return try_to_wake_up(curr->private, mode, wake_flags);
1da177e4 2575}
1da177e4
LT
2576EXPORT_SYMBOL(default_wake_function);
2577
2578/*
41a2d6cf
IM
2579 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
2580 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
1da177e4
LT
2581 * number) then we wake all the non-exclusive tasks and one exclusive task.
2582 *
2583 * There are circumstances in which we can try to wake a task which has already
41a2d6cf 2584 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
1da177e4
LT
2585 * zero in this (rare) case, and we handle it by continuing to scan the queue.
2586 */
78ddb08f 2587static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
63859d4f 2588 int nr_exclusive, int wake_flags, void *key)
1da177e4 2589{
2e45874c 2590 wait_queue_t *curr, *next;
1da177e4 2591
2e45874c 2592 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
48f24c4d
IM
2593 unsigned flags = curr->flags;
2594
63859d4f 2595 if (curr->func(curr, mode, wake_flags, key) &&
48f24c4d 2596 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
1da177e4
LT
2597 break;
2598 }
2599}
2600
2601/**
2602 * __wake_up - wake up threads blocked on a waitqueue.
2603 * @q: the waitqueue
2604 * @mode: which threads
2605 * @nr_exclusive: how many wake-one or wake-many threads to wake up
67be2dd1 2606 * @key: is directly passed to the wakeup function
50fa610a
DH
2607 *
2608 * It may be assumed that this function implies a write memory barrier before
2609 * changing the task state if and only if any tasks are woken up.
1da177e4 2610 */
7ad5b3a5 2611void __wake_up(wait_queue_head_t *q, unsigned int mode,
95cdf3b7 2612 int nr_exclusive, void *key)
1da177e4
LT
2613{
2614 unsigned long flags;
2615
2616 spin_lock_irqsave(&q->lock, flags);
2617 __wake_up_common(q, mode, nr_exclusive, 0, key);
2618 spin_unlock_irqrestore(&q->lock, flags);
2619}
1da177e4
LT
2620EXPORT_SYMBOL(__wake_up);
2621
2622/*
2623 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
2624 */
63b20011 2625void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr)
1da177e4 2626{
63b20011 2627 __wake_up_common(q, mode, nr, 0, NULL);
1da177e4 2628}
22c43c81 2629EXPORT_SYMBOL_GPL(__wake_up_locked);
1da177e4 2630
4ede816a
DL
2631void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
2632{
2633 __wake_up_common(q, mode, 1, 0, key);
2634}
bf294b41 2635EXPORT_SYMBOL_GPL(__wake_up_locked_key);
4ede816a 2636
1da177e4 2637/**
4ede816a 2638 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
1da177e4
LT
2639 * @q: the waitqueue
2640 * @mode: which threads
2641 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4ede816a 2642 * @key: opaque value to be passed to wakeup targets
1da177e4
LT
2643 *
2644 * The sync wakeup differs that the waker knows that it will schedule
2645 * away soon, so while the target thread will be woken up, it will not
2646 * be migrated to another CPU - ie. the two threads are 'synchronized'
2647 * with each other. This can prevent needless bouncing between CPUs.
2648 *
2649 * On UP it can prevent extra preemption.
50fa610a
DH
2650 *
2651 * It may be assumed that this function implies a write memory barrier before
2652 * changing the task state if and only if any tasks are woken up.
1da177e4 2653 */
4ede816a
DL
2654void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
2655 int nr_exclusive, void *key)
1da177e4
LT
2656{
2657 unsigned long flags;
7d478721 2658 int wake_flags = WF_SYNC;
1da177e4
LT
2659
2660 if (unlikely(!q))
2661 return;
2662
cedce3e7 2663 if (unlikely(nr_exclusive != 1))
7d478721 2664 wake_flags = 0;
1da177e4
LT
2665
2666 spin_lock_irqsave(&q->lock, flags);
7d478721 2667 __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
1da177e4
LT
2668 spin_unlock_irqrestore(&q->lock, flags);
2669}
4ede816a
DL
2670EXPORT_SYMBOL_GPL(__wake_up_sync_key);
2671
2672/*
2673 * __wake_up_sync - see __wake_up_sync_key()
2674 */
2675void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
2676{
2677 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
2678}
1da177e4
LT
2679EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
2680
65eb3dc6
KD
2681/**
2682 * complete: - signals a single thread waiting on this completion
2683 * @x: holds the state of this particular completion
2684 *
2685 * This will wake up a single thread waiting on this completion. Threads will be
2686 * awakened in the same order in which they were queued.
2687 *
2688 * See also complete_all(), wait_for_completion() and related routines.
50fa610a
DH
2689 *
2690 * It may be assumed that this function implies a write memory barrier before
2691 * changing the task state if and only if any tasks are woken up.
65eb3dc6 2692 */
b15136e9 2693void complete(struct completion *x)
1da177e4
LT
2694{
2695 unsigned long flags;
2696
2697 spin_lock_irqsave(&x->wait.lock, flags);
2698 x->done++;
d9514f6c 2699 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
1da177e4
LT
2700 spin_unlock_irqrestore(&x->wait.lock, flags);
2701}
2702EXPORT_SYMBOL(complete);
2703
65eb3dc6
KD
2704/**
2705 * complete_all: - signals all threads waiting on this completion
2706 * @x: holds the state of this particular completion
2707 *
2708 * This will wake up all threads waiting on this particular completion event.
50fa610a
DH
2709 *
2710 * It may be assumed that this function implies a write memory barrier before
2711 * changing the task state if and only if any tasks are woken up.
65eb3dc6 2712 */
b15136e9 2713void complete_all(struct completion *x)
1da177e4
LT
2714{
2715 unsigned long flags;
2716
2717 spin_lock_irqsave(&x->wait.lock, flags);
2718 x->done += UINT_MAX/2;
d9514f6c 2719 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
1da177e4
LT
2720 spin_unlock_irqrestore(&x->wait.lock, flags);
2721}
2722EXPORT_SYMBOL(complete_all);
2723
8cbbe86d 2724static inline long __sched
686855f5
VD
2725do_wait_for_common(struct completion *x,
2726 long (*action)(long), long timeout, int state)
1da177e4 2727{
1da177e4
LT
2728 if (!x->done) {
2729 DECLARE_WAITQUEUE(wait, current);
2730
a93d2f17 2731 __add_wait_queue_tail_exclusive(&x->wait, &wait);
1da177e4 2732 do {
94d3d824 2733 if (signal_pending_state(state, current)) {
ea71a546
ON
2734 timeout = -ERESTARTSYS;
2735 break;
8cbbe86d
AK
2736 }
2737 __set_current_state(state);
1da177e4 2738 spin_unlock_irq(&x->wait.lock);
686855f5 2739 timeout = action(timeout);
1da177e4 2740 spin_lock_irq(&x->wait.lock);
ea71a546 2741 } while (!x->done && timeout);
1da177e4 2742 __remove_wait_queue(&x->wait, &wait);
ea71a546
ON
2743 if (!x->done)
2744 return timeout;
1da177e4
LT
2745 }
2746 x->done--;
ea71a546 2747 return timeout ?: 1;
1da177e4 2748}
1da177e4 2749
686855f5
VD
2750static inline long __sched
2751__wait_for_common(struct completion *x,
2752 long (*action)(long), long timeout, int state)
1da177e4 2753{
1da177e4
LT
2754 might_sleep();
2755
2756 spin_lock_irq(&x->wait.lock);
686855f5 2757 timeout = do_wait_for_common(x, action, timeout, state);
1da177e4 2758 spin_unlock_irq(&x->wait.lock);
8cbbe86d
AK
2759 return timeout;
2760}
1da177e4 2761
686855f5
VD
2762static long __sched
2763wait_for_common(struct completion *x, long timeout, int state)
2764{
2765 return __wait_for_common(x, schedule_timeout, timeout, state);
2766}
2767
2768static long __sched
2769wait_for_common_io(struct completion *x, long timeout, int state)
2770{
2771 return __wait_for_common(x, io_schedule_timeout, timeout, state);
2772}
2773
65eb3dc6
KD
2774/**
2775 * wait_for_completion: - waits for completion of a task
2776 * @x: holds the state of this particular completion
2777 *
2778 * This waits to be signaled for completion of a specific task. It is NOT
2779 * interruptible and there is no timeout.
2780 *
2781 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
2782 * and interrupt capability. Also see complete().
2783 */
b15136e9 2784void __sched wait_for_completion(struct completion *x)
8cbbe86d
AK
2785{
2786 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
1da177e4 2787}
8cbbe86d 2788EXPORT_SYMBOL(wait_for_completion);
1da177e4 2789
65eb3dc6
KD
2790/**
2791 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
2792 * @x: holds the state of this particular completion
2793 * @timeout: timeout value in jiffies
2794 *
2795 * This waits for either a completion of a specific task to be signaled or for a
2796 * specified timeout to expire. The timeout is in jiffies. It is not
2797 * interruptible.
c6dc7f05 2798 *
e69f6186
YB
2799 * Return: 0 if timed out, and positive (at least 1, or number of jiffies left
2800 * till timeout) if completed.
65eb3dc6 2801 */
b15136e9 2802unsigned long __sched
8cbbe86d 2803wait_for_completion_timeout(struct completion *x, unsigned long timeout)
1da177e4 2804{
8cbbe86d 2805 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
1da177e4 2806}
8cbbe86d 2807EXPORT_SYMBOL(wait_for_completion_timeout);
1da177e4 2808
686855f5
VD
2809/**
2810 * wait_for_completion_io: - waits for completion of a task
2811 * @x: holds the state of this particular completion
2812 *
2813 * This waits to be signaled for completion of a specific task. It is NOT
2814 * interruptible and there is no timeout. The caller is accounted as waiting
2815 * for IO.
2816 */
2817void __sched wait_for_completion_io(struct completion *x)
2818{
2819 wait_for_common_io(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
2820}
2821EXPORT_SYMBOL(wait_for_completion_io);
2822
2823/**
2824 * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout)
2825 * @x: holds the state of this particular completion
2826 * @timeout: timeout value in jiffies
2827 *
2828 * This waits for either a completion of a specific task to be signaled or for a
2829 * specified timeout to expire. The timeout is in jiffies. It is not
2830 * interruptible. The caller is accounted as waiting for IO.
2831 *
e69f6186
YB
2832 * Return: 0 if timed out, and positive (at least 1, or number of jiffies left
2833 * till timeout) if completed.
686855f5
VD
2834 */
2835unsigned long __sched
2836wait_for_completion_io_timeout(struct completion *x, unsigned long timeout)
2837{
2838 return wait_for_common_io(x, timeout, TASK_UNINTERRUPTIBLE);
2839}
2840EXPORT_SYMBOL(wait_for_completion_io_timeout);
2841
65eb3dc6
KD
2842/**
2843 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
2844 * @x: holds the state of this particular completion
2845 *
2846 * This waits for completion of a specific task to be signaled. It is
2847 * interruptible.
c6dc7f05 2848 *
e69f6186 2849 * Return: -ERESTARTSYS if interrupted, 0 if completed.
65eb3dc6 2850 */
8cbbe86d 2851int __sched wait_for_completion_interruptible(struct completion *x)
0fec171c 2852{
51e97990
AK
2853 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
2854 if (t == -ERESTARTSYS)
2855 return t;
2856 return 0;
0fec171c 2857}
8cbbe86d 2858EXPORT_SYMBOL(wait_for_completion_interruptible);
1da177e4 2859
65eb3dc6
KD
2860/**
2861 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
2862 * @x: holds the state of this particular completion
2863 * @timeout: timeout value in jiffies
2864 *
2865 * This waits for either a completion of a specific task to be signaled or for a
2866 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
c6dc7f05 2867 *
e69f6186
YB
2868 * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
2869 * or number of jiffies left till timeout) if completed.
65eb3dc6 2870 */
6bf41237 2871long __sched
8cbbe86d
AK
2872wait_for_completion_interruptible_timeout(struct completion *x,
2873 unsigned long timeout)
0fec171c 2874{
8cbbe86d 2875 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
0fec171c 2876}
8cbbe86d 2877EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
1da177e4 2878
65eb3dc6
KD
2879/**
2880 * wait_for_completion_killable: - waits for completion of a task (killable)
2881 * @x: holds the state of this particular completion
2882 *
2883 * This waits to be signaled for completion of a specific task. It can be
2884 * interrupted by a kill signal.
c6dc7f05 2885 *
e69f6186 2886 * Return: -ERESTARTSYS if interrupted, 0 if completed.
65eb3dc6 2887 */
009e577e
MW
2888int __sched wait_for_completion_killable(struct completion *x)
2889{
2890 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
2891 if (t == -ERESTARTSYS)
2892 return t;
2893 return 0;
2894}
2895EXPORT_SYMBOL(wait_for_completion_killable);
2896
0aa12fb4
SW
2897/**
2898 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
2899 * @x: holds the state of this particular completion
2900 * @timeout: timeout value in jiffies
2901 *
2902 * This waits for either a completion of a specific task to be
2903 * signaled or for a specified timeout to expire. It can be
2904 * interrupted by a kill signal. The timeout is in jiffies.
c6dc7f05 2905 *
e69f6186
YB
2906 * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
2907 * or number of jiffies left till timeout) if completed.
0aa12fb4 2908 */
6bf41237 2909long __sched
0aa12fb4
SW
2910wait_for_completion_killable_timeout(struct completion *x,
2911 unsigned long timeout)
2912{
2913 return wait_for_common(x, timeout, TASK_KILLABLE);
2914}
2915EXPORT_SYMBOL(wait_for_completion_killable_timeout);
2916
be4de352
DC
2917/**
2918 * try_wait_for_completion - try to decrement a completion without blocking
2919 * @x: completion structure
2920 *
e69f6186 2921 * Return: 0 if a decrement cannot be done without blocking
be4de352
DC
2922 * 1 if a decrement succeeded.
2923 *
2924 * If a completion is being used as a counting completion,
2925 * attempt to decrement the counter without blocking. This
2926 * enables us to avoid waiting if the resource the completion
2927 * is protecting is not available.
2928 */
2929bool try_wait_for_completion(struct completion *x)
2930{
7539a3b3 2931 unsigned long flags;
be4de352
DC
2932 int ret = 1;
2933
7539a3b3 2934 spin_lock_irqsave(&x->wait.lock, flags);
be4de352
DC
2935 if (!x->done)
2936 ret = 0;
2937 else
2938 x->done--;
7539a3b3 2939 spin_unlock_irqrestore(&x->wait.lock, flags);
be4de352
DC
2940 return ret;
2941}
2942EXPORT_SYMBOL(try_wait_for_completion);
2943
2944/**
2945 * completion_done - Test to see if a completion has any waiters
2946 * @x: completion structure
2947 *
e69f6186 2948 * Return: 0 if there are waiters (wait_for_completion() in progress)
be4de352
DC
2949 * 1 if there are no waiters.
2950 *
2951 */
2952bool completion_done(struct completion *x)
2953{
7539a3b3 2954 unsigned long flags;
be4de352
DC
2955 int ret = 1;
2956
7539a3b3 2957 spin_lock_irqsave(&x->wait.lock, flags);
be4de352
DC
2958 if (!x->done)
2959 ret = 0;
7539a3b3 2960 spin_unlock_irqrestore(&x->wait.lock, flags);
be4de352
DC
2961 return ret;
2962}
2963EXPORT_SYMBOL(completion_done);
2964
8cbbe86d
AK
2965static long __sched
2966sleep_on_common(wait_queue_head_t *q, int state, long timeout)
1da177e4 2967{
0fec171c
IM
2968 unsigned long flags;
2969 wait_queue_t wait;
2970
2971 init_waitqueue_entry(&wait, current);
1da177e4 2972
8cbbe86d 2973 __set_current_state(state);
1da177e4 2974
8cbbe86d
AK
2975 spin_lock_irqsave(&q->lock, flags);
2976 __add_wait_queue(q, &wait);
2977 spin_unlock(&q->lock);
2978 timeout = schedule_timeout(timeout);
2979 spin_lock_irq(&q->lock);
2980 __remove_wait_queue(q, &wait);
2981 spin_unlock_irqrestore(&q->lock, flags);
2982
2983 return timeout;
2984}
2985
2986void __sched interruptible_sleep_on(wait_queue_head_t *q)
2987{
2988 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
1da177e4 2989}
1da177e4
LT
2990EXPORT_SYMBOL(interruptible_sleep_on);
2991
0fec171c 2992long __sched
95cdf3b7 2993interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
1da177e4 2994{
8cbbe86d 2995 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
1da177e4 2996}
1da177e4
LT
2997EXPORT_SYMBOL(interruptible_sleep_on_timeout);
2998
0fec171c 2999void __sched sleep_on(wait_queue_head_t *q)
1da177e4 3000{
8cbbe86d 3001 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
1da177e4 3002}
1da177e4
LT
3003EXPORT_SYMBOL(sleep_on);
3004
0fec171c 3005long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
1da177e4 3006{
8cbbe86d 3007 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
1da177e4 3008}
1da177e4
LT
3009EXPORT_SYMBOL(sleep_on_timeout);
3010
b29739f9
IM
3011#ifdef CONFIG_RT_MUTEXES
3012
3013/*
3014 * rt_mutex_setprio - set the current priority of a task
3015 * @p: task
3016 * @prio: prio value (kernel-internal form)
3017 *
3018 * This function changes the 'effective' priority of a task. It does
3019 * not touch ->normal_prio like __setscheduler().
3020 *
3021 * Used by the rt_mutex code to implement priority inheritance logic.
3022 */
36c8b586 3023void rt_mutex_setprio(struct task_struct *p, int prio)
b29739f9 3024{
83b699ed 3025 int oldprio, on_rq, running;
70b97a7f 3026 struct rq *rq;
83ab0aa0 3027 const struct sched_class *prev_class;
b29739f9
IM
3028
3029 BUG_ON(prio < 0 || prio > MAX_PRIO);
3030
0122ec5b 3031 rq = __task_rq_lock(p);
b29739f9 3032
1c4dd99b
TG
3033 /*
3034 * Idle task boosting is a nono in general. There is one
3035 * exception, when PREEMPT_RT and NOHZ is active:
3036 *
3037 * The idle task calls get_next_timer_interrupt() and holds
3038 * the timer wheel base->lock on the CPU and another CPU wants
3039 * to access the timer (probably to cancel it). We can safely
3040 * ignore the boosting request, as the idle CPU runs this code
3041 * with interrupts disabled and will complete the lock
3042 * protected section without being interrupted. So there is no
3043 * real need to boost.
3044 */
3045 if (unlikely(p == rq->idle)) {
3046 WARN_ON(p != rq->curr);
3047 WARN_ON(p->pi_blocked_on);
3048 goto out_unlock;
3049 }
3050
a8027073 3051 trace_sched_pi_setprio(p, prio);
d5f9f942 3052 oldprio = p->prio;
83ab0aa0 3053 prev_class = p->sched_class;
fd2f4419 3054 on_rq = p->on_rq;
051a1d1a 3055 running = task_current(rq, p);
0e1f3483 3056 if (on_rq)
69be72c1 3057 dequeue_task(rq, p, 0);
0e1f3483
HS
3058 if (running)
3059 p->sched_class->put_prev_task(rq, p);
dd41f596
IM
3060
3061 if (rt_prio(prio))
3062 p->sched_class = &rt_sched_class;
3063 else
3064 p->sched_class = &fair_sched_class;
3065
b29739f9
IM
3066 p->prio = prio;
3067
0e1f3483
HS
3068 if (running)
3069 p->sched_class->set_curr_task(rq);
da7a735e 3070 if (on_rq)
371fd7e7 3071 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
cb469845 3072
da7a735e 3073 check_class_changed(rq, p, prev_class, oldprio);
1c4dd99b 3074out_unlock:
0122ec5b 3075 __task_rq_unlock(rq);
b29739f9 3076}
b29739f9 3077#endif
36c8b586 3078void set_user_nice(struct task_struct *p, long nice)
1da177e4 3079{
dd41f596 3080 int old_prio, delta, on_rq;
1da177e4 3081 unsigned long flags;
70b97a7f 3082 struct rq *rq;
1da177e4
LT
3083
3084 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
3085 return;
3086 /*
3087 * We have to be careful, if called from sys_setpriority(),
3088 * the task might be in the middle of scheduling on another CPU.
3089 */
3090 rq = task_rq_lock(p, &flags);
3091 /*
3092 * The RT priorities are set via sched_setscheduler(), but we still
3093 * allow the 'normal' nice value to be set - but as expected
3094 * it wont have any effect on scheduling until the task is
dd41f596 3095 * SCHED_FIFO/SCHED_RR:
1da177e4 3096 */
e05606d3 3097 if (task_has_rt_policy(p)) {
1da177e4
LT
3098 p->static_prio = NICE_TO_PRIO(nice);
3099 goto out_unlock;
3100 }
fd2f4419 3101 on_rq = p->on_rq;
c09595f6 3102 if (on_rq)
69be72c1 3103 dequeue_task(rq, p, 0);
1da177e4 3104
1da177e4 3105 p->static_prio = NICE_TO_PRIO(nice);
2dd73a4f 3106 set_load_weight(p);
b29739f9
IM
3107 old_prio = p->prio;
3108 p->prio = effective_prio(p);
3109 delta = p->prio - old_prio;
1da177e4 3110
dd41f596 3111 if (on_rq) {
371fd7e7 3112 enqueue_task(rq, p, 0);
1da177e4 3113 /*
d5f9f942
AM
3114 * If the task increased its priority or is running and
3115 * lowered its priority, then reschedule its CPU:
1da177e4 3116 */
d5f9f942 3117 if (delta < 0 || (delta > 0 && task_running(rq, p)))
1da177e4
LT
3118 resched_task(rq->curr);
3119 }
3120out_unlock:
0122ec5b 3121 task_rq_unlock(rq, p, &flags);
1da177e4 3122}
1da177e4
LT
3123EXPORT_SYMBOL(set_user_nice);
3124
e43379f1
MM
3125/*
3126 * can_nice - check if a task can reduce its nice value
3127 * @p: task
3128 * @nice: nice value
3129 */
36c8b586 3130int can_nice(const struct task_struct *p, const int nice)
e43379f1 3131{
024f4747
MM
3132 /* convert nice value [19,-20] to rlimit style value [1,40] */
3133 int nice_rlim = 20 - nice;
48f24c4d 3134
78d7d407 3135 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
e43379f1
MM
3136 capable(CAP_SYS_NICE));
3137}
3138
1da177e4
LT
3139#ifdef __ARCH_WANT_SYS_NICE
3140
3141/*
3142 * sys_nice - change the priority of the current process.
3143 * @increment: priority increment
3144 *
3145 * sys_setpriority is a more generic, but much slower function that
3146 * does similar things.
3147 */
5add95d4 3148SYSCALL_DEFINE1(nice, int, increment)
1da177e4 3149{
48f24c4d 3150 long nice, retval;
1da177e4
LT
3151
3152 /*
3153 * Setpriority might change our priority at the same moment.
3154 * We don't have to worry. Conceptually one call occurs first
3155 * and we have a single winner.
3156 */
e43379f1
MM
3157 if (increment < -40)
3158 increment = -40;
1da177e4
LT
3159 if (increment > 40)
3160 increment = 40;
3161
2b8f836f 3162 nice = TASK_NICE(current) + increment;
1da177e4
LT
3163 if (nice < -20)
3164 nice = -20;
3165 if (nice > 19)
3166 nice = 19;
3167
e43379f1
MM
3168 if (increment < 0 && !can_nice(current, nice))
3169 return -EPERM;
3170
1da177e4
LT
3171 retval = security_task_setnice(current, nice);
3172 if (retval)
3173 return retval;
3174
3175 set_user_nice(current, nice);
3176 return 0;
3177}
3178
3179#endif
3180
3181/**
3182 * task_prio - return the priority value of a given task.
3183 * @p: the task in question.
3184 *
e69f6186 3185 * Return: The priority value as seen by users in /proc.
1da177e4
LT
3186 * RT tasks are offset by -200. Normal tasks are centered
3187 * around 0, value goes from -16 to +15.
3188 */
36c8b586 3189int task_prio(const struct task_struct *p)
1da177e4
LT
3190{
3191 return p->prio - MAX_RT_PRIO;
3192}
3193
3194/**
3195 * task_nice - return the nice value of a given task.
3196 * @p: the task in question.
e69f6186
YB
3197 *
3198 * Return: The nice value [ -20 ... 0 ... 19 ].
1da177e4 3199 */
36c8b586 3200int task_nice(const struct task_struct *p)
1da177e4
LT
3201{
3202 return TASK_NICE(p);
3203}
150d8bed 3204EXPORT_SYMBOL(task_nice);
1da177e4
LT
3205
3206/**
3207 * idle_cpu - is a given cpu idle currently?
3208 * @cpu: the processor in question.
e69f6186
YB
3209 *
3210 * Return: 1 if the CPU is currently idle. 0 otherwise.
1da177e4
LT
3211 */
3212int idle_cpu(int cpu)
3213{
908a3283
TG
3214 struct rq *rq = cpu_rq(cpu);
3215
3216 if (rq->curr != rq->idle)
3217 return 0;
3218
3219 if (rq->nr_running)
3220 return 0;
3221
3222#ifdef CONFIG_SMP
3223 if (!llist_empty(&rq->wake_list))
3224 return 0;
3225#endif
3226
3227 return 1;
1da177e4
LT
3228}
3229
1da177e4
LT
3230/**
3231 * idle_task - return the idle task for a given cpu.
3232 * @cpu: the processor in question.
e69f6186
YB
3233 *
3234 * Return: The idle task for the cpu @cpu.
1da177e4 3235 */
36c8b586 3236struct task_struct *idle_task(int cpu)
1da177e4
LT
3237{
3238 return cpu_rq(cpu)->idle;
3239}
3240
3241/**
3242 * find_process_by_pid - find a process with a matching PID value.
3243 * @pid: the pid in question.
e69f6186
YB
3244 *
3245 * The task of @pid, if found. %NULL otherwise.
1da177e4 3246 */
a9957449 3247static struct task_struct *find_process_by_pid(pid_t pid)
1da177e4 3248{
228ebcbe 3249 return pid ? find_task_by_vpid(pid) : current;
1da177e4
LT
3250}
3251
3252/* Actually do priority change: must hold rq lock. */
dd41f596
IM
3253static void
3254__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
1da177e4 3255{
1da177e4
LT
3256 p->policy = policy;
3257 p->rt_priority = prio;
b29739f9
IM
3258 p->normal_prio = normal_prio(p);
3259 /* we are holding p->pi_lock already */
3260 p->prio = rt_mutex_getprio(p);
ffd44db5
PZ
3261 if (rt_prio(p->prio))
3262 p->sched_class = &rt_sched_class;
3263 else
3264 p->sched_class = &fair_sched_class;
2dd73a4f 3265 set_load_weight(p);
1da177e4
LT
3266}
3267
c69e8d9c
DH
3268/*
3269 * check the target process has a UID that matches the current process's
3270 */
3271static bool check_same_owner(struct task_struct *p)
3272{
3273 const struct cred *cred = current_cred(), *pcred;
3274 bool match;
3275
3276 rcu_read_lock();
3277 pcred = __task_cred(p);
9c806aa0
EB
3278 match = (uid_eq(cred->euid, pcred->euid) ||
3279 uid_eq(cred->euid, pcred->uid));
c69e8d9c
DH
3280 rcu_read_unlock();
3281 return match;
3282}
3283
961ccddd 3284static int __sched_setscheduler(struct task_struct *p, int policy,
fe7de49f 3285 const struct sched_param *param, bool user)
1da177e4 3286{
83b699ed 3287 int retval, oldprio, oldpolicy = -1, on_rq, running;
1da177e4 3288 unsigned long flags;
83ab0aa0 3289 const struct sched_class *prev_class;
70b97a7f 3290 struct rq *rq;
ca94c442 3291 int reset_on_fork;
1da177e4 3292
66e5393a
SR
3293 /* may grab non-irq protected spin_locks */
3294 BUG_ON(in_interrupt());
1da177e4
LT
3295recheck:
3296 /* double check policy once rq lock held */
ca94c442
LP
3297 if (policy < 0) {
3298 reset_on_fork = p->sched_reset_on_fork;
1da177e4 3299 policy = oldpolicy = p->policy;
ca94c442
LP
3300 } else {
3301 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
3302 policy &= ~SCHED_RESET_ON_FORK;
3303
3304 if (policy != SCHED_FIFO && policy != SCHED_RR &&
3305 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
3306 policy != SCHED_IDLE)
3307 return -EINVAL;
3308 }
3309
1da177e4
LT
3310 /*
3311 * Valid priorities for SCHED_FIFO and SCHED_RR are
dd41f596
IM
3312 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3313 * SCHED_BATCH and SCHED_IDLE is 0.
1da177e4
LT
3314 */
3315 if (param->sched_priority < 0 ||
95cdf3b7 3316 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
d46523ea 3317 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
1da177e4 3318 return -EINVAL;
e05606d3 3319 if (rt_policy(policy) != (param->sched_priority != 0))
1da177e4
LT
3320 return -EINVAL;
3321
37e4ab3f
OC
3322 /*
3323 * Allow unprivileged RT tasks to decrease priority:
3324 */
961ccddd 3325 if (user && !capable(CAP_SYS_NICE)) {
e05606d3 3326 if (rt_policy(policy)) {
a44702e8
ON
3327 unsigned long rlim_rtprio =
3328 task_rlimit(p, RLIMIT_RTPRIO);
8dc3e909
ON
3329
3330 /* can't set/change the rt policy */
3331 if (policy != p->policy && !rlim_rtprio)
3332 return -EPERM;
3333
3334 /* can't increase priority */
3335 if (param->sched_priority > p->rt_priority &&
3336 param->sched_priority > rlim_rtprio)
3337 return -EPERM;
3338 }
c02aa73b 3339
dd41f596 3340 /*
c02aa73b
DH
3341 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3342 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
dd41f596 3343 */
c02aa73b
DH
3344 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
3345 if (!can_nice(p, TASK_NICE(p)))
3346 return -EPERM;
3347 }
5fe1d75f 3348
37e4ab3f 3349 /* can't change other user's priorities */
c69e8d9c 3350 if (!check_same_owner(p))
37e4ab3f 3351 return -EPERM;
ca94c442
LP
3352
3353 /* Normal users shall not reset the sched_reset_on_fork flag */
3354 if (p->sched_reset_on_fork && !reset_on_fork)
3355 return -EPERM;
37e4ab3f 3356 }
1da177e4 3357
725aad24 3358 if (user) {
b0ae1981 3359 retval = security_task_setscheduler(p);
725aad24
JF
3360 if (retval)
3361 return retval;
3362 }
3363
b29739f9
IM
3364 /*
3365 * make sure no PI-waiters arrive (or leave) while we are
3366 * changing the priority of the task:
0122ec5b 3367 *
25985edc 3368 * To be able to change p->policy safely, the appropriate
1da177e4
LT
3369 * runqueue lock must be held.
3370 */
0122ec5b 3371 rq = task_rq_lock(p, &flags);
dc61b1d6 3372
34f971f6
PZ
3373 /*
3374 * Changing the policy of the stop threads its a very bad idea
3375 */
3376 if (p == rq->stop) {
0122ec5b 3377 task_rq_unlock(rq, p, &flags);
34f971f6
PZ
3378 return -EINVAL;
3379 }
3380
a51e9198
DF
3381 /*
3382 * If not changing anything there's no need to proceed further:
3383 */
3384 if (unlikely(policy == p->policy && (!rt_policy(policy) ||
3385 param->sched_priority == p->rt_priority))) {
45afb173 3386 task_rq_unlock(rq, p, &flags);
a51e9198
DF
3387 return 0;
3388 }
3389
dc61b1d6
PZ
3390#ifdef CONFIG_RT_GROUP_SCHED
3391 if (user) {
3392 /*
3393 * Do not allow realtime tasks into groups that have no runtime
3394 * assigned.
3395 */
3396 if (rt_bandwidth_enabled() && rt_policy(policy) &&
f4493771
MG
3397 task_group(p)->rt_bandwidth.rt_runtime == 0 &&
3398 !task_group_is_autogroup(task_group(p))) {
0122ec5b 3399 task_rq_unlock(rq, p, &flags);
dc61b1d6
PZ
3400 return -EPERM;
3401 }
3402 }
3403#endif
3404
1da177e4
LT
3405 /* recheck policy now with rq lock held */
3406 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
3407 policy = oldpolicy = -1;
0122ec5b 3408 task_rq_unlock(rq, p, &flags);
1da177e4
LT
3409 goto recheck;
3410 }
fd2f4419 3411 on_rq = p->on_rq;
051a1d1a 3412 running = task_current(rq, p);
0e1f3483 3413 if (on_rq)
4ca9b72b 3414 dequeue_task(rq, p, 0);
0e1f3483
HS
3415 if (running)
3416 p->sched_class->put_prev_task(rq, p);
f6b53205 3417
ca94c442
LP
3418 p->sched_reset_on_fork = reset_on_fork;
3419
1da177e4 3420 oldprio = p->prio;
83ab0aa0 3421 prev_class = p->sched_class;
dd41f596 3422 __setscheduler(rq, p, policy, param->sched_priority);
f6b53205 3423
0e1f3483
HS
3424 if (running)
3425 p->sched_class->set_curr_task(rq);
da7a735e 3426 if (on_rq)
4ca9b72b 3427 enqueue_task(rq, p, 0);
cb469845 3428
da7a735e 3429 check_class_changed(rq, p, prev_class, oldprio);
0122ec5b 3430 task_rq_unlock(rq, p, &flags);
b29739f9 3431
95e02ca9
TG
3432 rt_mutex_adjust_pi(p);
3433
1da177e4
LT
3434 return 0;
3435}
961ccddd
RR
3436
3437/**
3438 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3439 * @p: the task in question.
3440 * @policy: new policy.
3441 * @param: structure containing the new RT priority.
3442 *
e69f6186
YB
3443 * Return: 0 on success. An error code otherwise.
3444 *
961ccddd
RR
3445 * NOTE that the task may be already dead.
3446 */
3447int sched_setscheduler(struct task_struct *p, int policy,
fe7de49f 3448 const struct sched_param *param)
961ccddd
RR
3449{
3450 return __sched_setscheduler(p, policy, param, true);
3451}
1da177e4
LT
3452EXPORT_SYMBOL_GPL(sched_setscheduler);
3453
961ccddd
RR
3454/**
3455 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3456 * @p: the task in question.
3457 * @policy: new policy.
3458 * @param: structure containing the new RT priority.
3459 *
3460 * Just like sched_setscheduler, only don't bother checking if the
3461 * current context has permission. For example, this is needed in
3462 * stop_machine(): we create temporary high priority worker threads,
3463 * but our caller might not have that capability.
e69f6186
YB
3464 *
3465 * Return: 0 on success. An error code otherwise.
961ccddd
RR
3466 */
3467int sched_setscheduler_nocheck(struct task_struct *p, int policy,
fe7de49f 3468 const struct sched_param *param)
961ccddd
RR
3469{
3470 return __sched_setscheduler(p, policy, param, false);
3471}
3472
95cdf3b7
IM
3473static int
3474do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
1da177e4 3475{
1da177e4
LT
3476 struct sched_param lparam;
3477 struct task_struct *p;
36c8b586 3478 int retval;
1da177e4
LT
3479
3480 if (!param || pid < 0)
3481 return -EINVAL;
3482 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
3483 return -EFAULT;
5fe1d75f
ON
3484
3485 rcu_read_lock();
3486 retval = -ESRCH;
1da177e4 3487 p = find_process_by_pid(pid);
5fe1d75f
ON
3488 if (p != NULL)
3489 retval = sched_setscheduler(p, policy, &lparam);
3490 rcu_read_unlock();
36c8b586 3491
1da177e4
LT
3492 return retval;
3493}
3494
3495/**
3496 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3497 * @pid: the pid in question.
3498 * @policy: new policy.
3499 * @param: structure containing the new RT priority.
e69f6186
YB
3500 *
3501 * Return: 0 on success. An error code otherwise.
1da177e4 3502 */
5add95d4
HC
3503SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
3504 struct sched_param __user *, param)
1da177e4 3505{
c21761f1
JB
3506 /* negative values for policy are not valid */
3507 if (policy < 0)
3508 return -EINVAL;
3509
1da177e4
LT
3510 return do_sched_setscheduler(pid, policy, param);
3511}
3512
3513/**
3514 * sys_sched_setparam - set/change the RT priority of a thread
3515 * @pid: the pid in question.
3516 * @param: structure containing the new RT priority.
e69f6186
YB
3517 *
3518 * Return: 0 on success. An error code otherwise.
1da177e4 3519 */
5add95d4 3520SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
1da177e4
LT
3521{
3522 return do_sched_setscheduler(pid, -1, param);
3523}
3524
3525/**
3526 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3527 * @pid: the pid in question.
e69f6186
YB
3528 *
3529 * Return: On success, the policy of the thread. Otherwise, a negative error
3530 * code.
1da177e4 3531 */
5add95d4 3532SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
1da177e4 3533{
36c8b586 3534 struct task_struct *p;
3a5c359a 3535 int retval;
1da177e4
LT
3536
3537 if (pid < 0)
3a5c359a 3538 return -EINVAL;
1da177e4
LT
3539
3540 retval = -ESRCH;
5fe85be0 3541 rcu_read_lock();
1da177e4
LT
3542 p = find_process_by_pid(pid);
3543 if (p) {
3544 retval = security_task_getscheduler(p);
3545 if (!retval)
ca94c442
LP
3546 retval = p->policy
3547 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
1da177e4 3548 }
5fe85be0 3549 rcu_read_unlock();
1da177e4
LT
3550 return retval;
3551}
3552
3553/**
ca94c442 3554 * sys_sched_getparam - get the RT priority of a thread
1da177e4
LT
3555 * @pid: the pid in question.
3556 * @param: structure containing the RT priority.
e69f6186
YB
3557 *
3558 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3559 * code.
1da177e4 3560 */
5add95d4 3561SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
1da177e4
LT
3562{
3563 struct sched_param lp;
36c8b586 3564 struct task_struct *p;
3a5c359a 3565 int retval;
1da177e4
LT
3566
3567 if (!param || pid < 0)
3a5c359a 3568 return -EINVAL;
1da177e4 3569
5fe85be0 3570 rcu_read_lock();
1da177e4
LT
3571 p = find_process_by_pid(pid);
3572 retval = -ESRCH;
3573 if (!p)
3574 goto out_unlock;
3575
3576 retval = security_task_getscheduler(p);
3577 if (retval)
3578 goto out_unlock;
3579
3580 lp.sched_priority = p->rt_priority;
5fe85be0 3581 rcu_read_unlock();
1da177e4
LT
3582
3583 /*
3584 * This one might sleep, we cannot do it with a spinlock held ...
3585 */
3586 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
3587
1da177e4
LT
3588 return retval;
3589
3590out_unlock:
5fe85be0 3591 rcu_read_unlock();
1da177e4
LT
3592 return retval;
3593}
3594
96f874e2 3595long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
1da177e4 3596{
5a16f3d3 3597 cpumask_var_t cpus_allowed, new_mask;
36c8b586
IM
3598 struct task_struct *p;
3599 int retval;
1da177e4 3600
95402b38 3601 get_online_cpus();
23f5d142 3602 rcu_read_lock();
1da177e4
LT
3603
3604 p = find_process_by_pid(pid);
3605 if (!p) {
23f5d142 3606 rcu_read_unlock();
95402b38 3607 put_online_cpus();
1da177e4
LT
3608 return -ESRCH;
3609 }
3610
23f5d142 3611 /* Prevent p going away */
1da177e4 3612 get_task_struct(p);
23f5d142 3613 rcu_read_unlock();
1da177e4 3614
14a40ffc
TH
3615 if (p->flags & PF_NO_SETAFFINITY) {
3616 retval = -EINVAL;
3617 goto out_put_task;
3618 }
5a16f3d3
RR
3619 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
3620 retval = -ENOMEM;
3621 goto out_put_task;
3622 }
3623 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
3624 retval = -ENOMEM;
3625 goto out_free_cpus_allowed;
3626 }
1da177e4 3627 retval = -EPERM;
4c44aaaf
EB
3628 if (!check_same_owner(p)) {
3629 rcu_read_lock();
3630 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
3631 rcu_read_unlock();
3632 goto out_unlock;
3633 }
3634 rcu_read_unlock();
3635 }
1da177e4 3636
b0ae1981 3637 retval = security_task_setscheduler(p);
e7834f8f
DQ
3638 if (retval)
3639 goto out_unlock;
3640
5a16f3d3
RR
3641 cpuset_cpus_allowed(p, cpus_allowed);
3642 cpumask_and(new_mask, in_mask, cpus_allowed);
49246274 3643again:
5a16f3d3 3644 retval = set_cpus_allowed_ptr(p, new_mask);
1da177e4 3645
8707d8b8 3646 if (!retval) {
5a16f3d3
RR
3647 cpuset_cpus_allowed(p, cpus_allowed);
3648 if (!cpumask_subset(new_mask, cpus_allowed)) {
8707d8b8
PM
3649 /*
3650 * We must have raced with a concurrent cpuset
3651 * update. Just reset the cpus_allowed to the
3652 * cpuset's cpus_allowed
3653 */
5a16f3d3 3654 cpumask_copy(new_mask, cpus_allowed);
8707d8b8
PM
3655 goto again;
3656 }
3657 }
1da177e4 3658out_unlock:
5a16f3d3
RR
3659 free_cpumask_var(new_mask);
3660out_free_cpus_allowed:
3661 free_cpumask_var(cpus_allowed);
3662out_put_task:
1da177e4 3663 put_task_struct(p);
95402b38 3664 put_online_cpus();
1da177e4
LT
3665 return retval;
3666}
3667
3668static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
96f874e2 3669 struct cpumask *new_mask)
1da177e4 3670{
96f874e2
RR
3671 if (len < cpumask_size())
3672 cpumask_clear(new_mask);
3673 else if (len > cpumask_size())
3674 len = cpumask_size();
3675
1da177e4
LT
3676 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
3677}
3678
3679/**
3680 * sys_sched_setaffinity - set the cpu affinity of a process
3681 * @pid: pid of the process
3682 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3683 * @user_mask_ptr: user-space pointer to the new cpu mask
e69f6186
YB
3684 *
3685 * Return: 0 on success. An error code otherwise.
1da177e4 3686 */
5add95d4
HC
3687SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
3688 unsigned long __user *, user_mask_ptr)
1da177e4 3689{
5a16f3d3 3690 cpumask_var_t new_mask;
1da177e4
LT
3691 int retval;
3692
5a16f3d3
RR
3693 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
3694 return -ENOMEM;
1da177e4 3695
5a16f3d3
RR
3696 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
3697 if (retval == 0)
3698 retval = sched_setaffinity(pid, new_mask);
3699 free_cpumask_var(new_mask);
3700 return retval;
1da177e4
LT
3701}
3702
96f874e2 3703long sched_getaffinity(pid_t pid, struct cpumask *mask)
1da177e4 3704{
36c8b586 3705 struct task_struct *p;
31605683 3706 unsigned long flags;
1da177e4 3707 int retval;
1da177e4 3708
95402b38 3709 get_online_cpus();
23f5d142 3710 rcu_read_lock();
1da177e4
LT
3711
3712 retval = -ESRCH;
3713 p = find_process_by_pid(pid);
3714 if (!p)
3715 goto out_unlock;
3716
e7834f8f
DQ
3717 retval = security_task_getscheduler(p);
3718 if (retval)
3719 goto out_unlock;
3720
013fdb80 3721 raw_spin_lock_irqsave(&p->pi_lock, flags);
96f874e2 3722 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
013fdb80 3723 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1da177e4
LT
3724
3725out_unlock:
23f5d142 3726 rcu_read_unlock();
95402b38 3727 put_online_cpus();
1da177e4 3728
9531b62f 3729 return retval;
1da177e4
LT
3730}
3731
3732/**
3733 * sys_sched_getaffinity - get the cpu affinity of a process
3734 * @pid: pid of the process
3735 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3736 * @user_mask_ptr: user-space pointer to hold the current cpu mask
e69f6186
YB
3737 *
3738 * Return: 0 on success. An error code otherwise.
1da177e4 3739 */
5add95d4
HC
3740SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
3741 unsigned long __user *, user_mask_ptr)
1da177e4
LT
3742{
3743 int ret;
f17c8607 3744 cpumask_var_t mask;
1da177e4 3745
84fba5ec 3746 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
cd3d8031
KM
3747 return -EINVAL;
3748 if (len & (sizeof(unsigned long)-1))
1da177e4
LT
3749 return -EINVAL;
3750
f17c8607
RR
3751 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
3752 return -ENOMEM;
1da177e4 3753
f17c8607
RR
3754 ret = sched_getaffinity(pid, mask);
3755 if (ret == 0) {
8bc037fb 3756 size_t retlen = min_t(size_t, len, cpumask_size());
cd3d8031
KM
3757
3758 if (copy_to_user(user_mask_ptr, mask, retlen))
f17c8607
RR
3759 ret = -EFAULT;
3760 else
cd3d8031 3761 ret = retlen;
f17c8607
RR
3762 }
3763 free_cpumask_var(mask);
1da177e4 3764
f17c8607 3765 return ret;
1da177e4
LT
3766}
3767
3768/**
3769 * sys_sched_yield - yield the current processor to other threads.
3770 *
dd41f596
IM
3771 * This function yields the current CPU to other tasks. If there are no
3772 * other threads running on this CPU then this function will return.
e69f6186
YB
3773 *
3774 * Return: 0.
1da177e4 3775 */
5add95d4 3776SYSCALL_DEFINE0(sched_yield)
1da177e4 3777{
70b97a7f 3778 struct rq *rq = this_rq_lock();
1da177e4 3779
2d72376b 3780 schedstat_inc(rq, yld_count);
4530d7ab 3781 current->sched_class->yield_task(rq);
1da177e4
LT
3782
3783 /*
3784 * Since we are going to call schedule() anyway, there's
3785 * no need to preempt or enable interrupts:
3786 */
3787 __release(rq->lock);
8a25d5de 3788 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
9828ea9d 3789 do_raw_spin_unlock(&rq->lock);
ba74c144 3790 sched_preempt_enable_no_resched();
1da177e4
LT
3791
3792 schedule();
3793
3794 return 0;
3795}
3796
d86ee480
PZ
3797static inline int should_resched(void)
3798{
3799 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
3800}
3801
e7b38404 3802static void __cond_resched(void)
1da177e4 3803{
e7aaaa69 3804 add_preempt_count(PREEMPT_ACTIVE);
c259e01a 3805 __schedule();
e7aaaa69 3806 sub_preempt_count(PREEMPT_ACTIVE);
1da177e4
LT
3807}
3808
02b67cc3 3809int __sched _cond_resched(void)
1da177e4 3810{
d86ee480 3811 if (should_resched()) {
1da177e4
LT
3812 __cond_resched();
3813 return 1;
3814 }
3815 return 0;
3816}
02b67cc3 3817EXPORT_SYMBOL(_cond_resched);
1da177e4
LT
3818
3819/*
613afbf8 3820 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
1da177e4
LT
3821 * call schedule, and on return reacquire the lock.
3822 *
41a2d6cf 3823 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
1da177e4
LT
3824 * operations here to prevent schedule() from being called twice (once via
3825 * spin_unlock(), once by hand).
3826 */
613afbf8 3827int __cond_resched_lock(spinlock_t *lock)
1da177e4 3828{
d86ee480 3829 int resched = should_resched();
6df3cecb
JK
3830 int ret = 0;
3831
f607c668
PZ
3832 lockdep_assert_held(lock);
3833
95c354fe 3834 if (spin_needbreak(lock) || resched) {
1da177e4 3835 spin_unlock(lock);
d86ee480 3836 if (resched)
95c354fe
NP
3837 __cond_resched();
3838 else
3839 cpu_relax();
6df3cecb 3840 ret = 1;
1da177e4 3841 spin_lock(lock);
1da177e4 3842 }
6df3cecb 3843 return ret;
1da177e4 3844}
613afbf8 3845EXPORT_SYMBOL(__cond_resched_lock);
1da177e4 3846
613afbf8 3847int __sched __cond_resched_softirq(void)
1da177e4
LT
3848{
3849 BUG_ON(!in_softirq());
3850
d86ee480 3851 if (should_resched()) {
98d82567 3852 local_bh_enable();
1da177e4
LT
3853 __cond_resched();
3854 local_bh_disable();
3855 return 1;
3856 }
3857 return 0;
3858}
613afbf8 3859EXPORT_SYMBOL(__cond_resched_softirq);
1da177e4 3860
1da177e4
LT
3861/**
3862 * yield - yield the current processor to other threads.
3863 *
8e3fabfd
PZ
3864 * Do not ever use this function, there's a 99% chance you're doing it wrong.
3865 *
3866 * The scheduler is at all times free to pick the calling task as the most
3867 * eligible task to run, if removing the yield() call from your code breaks
3868 * it, its already broken.
3869 *
3870 * Typical broken usage is:
3871 *
3872 * while (!event)
3873 * yield();
3874 *
3875 * where one assumes that yield() will let 'the other' process run that will
3876 * make event true. If the current task is a SCHED_FIFO task that will never
3877 * happen. Never use yield() as a progress guarantee!!
3878 *
3879 * If you want to use yield() to wait for something, use wait_event().
3880 * If you want to use yield() to be 'nice' for others, use cond_resched().
3881 * If you still want to use yield(), do not!
1da177e4
LT
3882 */
3883void __sched yield(void)
3884{
3885 set_current_state(TASK_RUNNING);
3886 sys_sched_yield();
3887}
1da177e4
LT
3888EXPORT_SYMBOL(yield);
3889
d95f4122
MG
3890/**
3891 * yield_to - yield the current processor to another thread in
3892 * your thread group, or accelerate that thread toward the
3893 * processor it's on.
16addf95
RD
3894 * @p: target task
3895 * @preempt: whether task preemption is allowed or not
d95f4122
MG
3896 *
3897 * It's the caller's job to ensure that the target task struct
3898 * can't go away on us before we can do any checks.
3899 *
e69f6186 3900 * Return:
7b270f60
PZ
3901 * true (>0) if we indeed boosted the target task.
3902 * false (0) if we failed to boost the target.
3903 * -ESRCH if there's no task to yield to.
d95f4122
MG
3904 */
3905bool __sched yield_to(struct task_struct *p, bool preempt)
3906{
3907 struct task_struct *curr = current;
3908 struct rq *rq, *p_rq;
3909 unsigned long flags;
c3c18640 3910 int yielded = 0;
d95f4122
MG
3911
3912 local_irq_save(flags);
3913 rq = this_rq();
3914
3915again:
3916 p_rq = task_rq(p);
7b270f60
PZ
3917 /*
3918 * If we're the only runnable task on the rq and target rq also
3919 * has only one task, there's absolutely no point in yielding.
3920 */
3921 if (rq->nr_running == 1 && p_rq->nr_running == 1) {
3922 yielded = -ESRCH;
3923 goto out_irq;
3924 }
3925
d95f4122
MG
3926 double_rq_lock(rq, p_rq);
3927 while (task_rq(p) != p_rq) {
3928 double_rq_unlock(rq, p_rq);
3929 goto again;
3930 }
3931
3932 if (!curr->sched_class->yield_to_task)
7b270f60 3933 goto out_unlock;
d95f4122
MG
3934
3935 if (curr->sched_class != p->sched_class)
7b270f60 3936 goto out_unlock;
d95f4122
MG
3937
3938 if (task_running(p_rq, p) || p->state)
7b270f60 3939 goto out_unlock;
d95f4122
MG
3940
3941 yielded = curr->sched_class->yield_to_task(rq, p, preempt);
6d1cafd8 3942 if (yielded) {
d95f4122 3943 schedstat_inc(rq, yld_count);
6d1cafd8
VP
3944 /*
3945 * Make p's CPU reschedule; pick_next_entity takes care of
3946 * fairness.
3947 */
3948 if (preempt && rq != p_rq)
3949 resched_task(p_rq->curr);
3950 }
d95f4122 3951
7b270f60 3952out_unlock:
d95f4122 3953 double_rq_unlock(rq, p_rq);
7b270f60 3954out_irq:
d95f4122
MG
3955 local_irq_restore(flags);
3956
7b270f60 3957 if (yielded > 0)
d95f4122
MG
3958 schedule();
3959
3960 return yielded;
3961}
3962EXPORT_SYMBOL_GPL(yield_to);
3963
1da177e4 3964/*
41a2d6cf 3965 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
1da177e4 3966 * that process accounting knows that this is a task in IO wait state.
1da177e4
LT
3967 */
3968void __sched io_schedule(void)
3969{
54d35f29 3970 struct rq *rq = raw_rq();
1da177e4 3971
0ff92245 3972 delayacct_blkio_start();
1da177e4 3973 atomic_inc(&rq->nr_iowait);
73c10101 3974 blk_flush_plug(current);
8f0dfc34 3975 current->in_iowait = 1;
1da177e4 3976 schedule();
8f0dfc34 3977 current->in_iowait = 0;
1da177e4 3978 atomic_dec(&rq->nr_iowait);
0ff92245 3979 delayacct_blkio_end();
1da177e4 3980}
1da177e4
LT
3981EXPORT_SYMBOL(io_schedule);
3982
3983long __sched io_schedule_timeout(long timeout)
3984{
54d35f29 3985 struct rq *rq = raw_rq();
1da177e4
LT
3986 long ret;
3987
0ff92245 3988 delayacct_blkio_start();
1da177e4 3989 atomic_inc(&rq->nr_iowait);
73c10101 3990 blk_flush_plug(current);
8f0dfc34 3991 current->in_iowait = 1;
1da177e4 3992 ret = schedule_timeout(timeout);
8f0dfc34 3993 current->in_iowait = 0;
1da177e4 3994 atomic_dec(&rq->nr_iowait);
0ff92245 3995 delayacct_blkio_end();
1da177e4
LT
3996 return ret;
3997}
3998
3999/**
4000 * sys_sched_get_priority_max - return maximum RT priority.
4001 * @policy: scheduling class.
4002 *
e69f6186
YB
4003 * Return: On success, this syscall returns the maximum
4004 * rt_priority that can be used by a given scheduling class.
4005 * On failure, a negative error code is returned.
1da177e4 4006 */
5add95d4 4007SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
1da177e4
LT
4008{
4009 int ret = -EINVAL;
4010
4011 switch (policy) {
4012 case SCHED_FIFO:
4013 case SCHED_RR:
4014 ret = MAX_USER_RT_PRIO-1;
4015 break;
4016 case SCHED_NORMAL:
b0a9499c 4017 case SCHED_BATCH:
dd41f596 4018 case SCHED_IDLE:
1da177e4
LT
4019 ret = 0;
4020 break;
4021 }
4022 return ret;
4023}
4024
4025/**
4026 * sys_sched_get_priority_min - return minimum RT priority.
4027 * @policy: scheduling class.
4028 *
e69f6186
YB
4029 * Return: On success, this syscall returns the minimum
4030 * rt_priority that can be used by a given scheduling class.
4031 * On failure, a negative error code is returned.
1da177e4 4032 */
5add95d4 4033SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
1da177e4
LT
4034{
4035 int ret = -EINVAL;
4036
4037 switch (policy) {
4038 case SCHED_FIFO:
4039 case SCHED_RR:
4040 ret = 1;
4041 break;
4042 case SCHED_NORMAL:
b0a9499c 4043 case SCHED_BATCH:
dd41f596 4044 case SCHED_IDLE:
1da177e4
LT
4045 ret = 0;
4046 }
4047 return ret;
4048}
4049
4050/**
4051 * sys_sched_rr_get_interval - return the default timeslice of a process.
4052 * @pid: pid of the process.
4053 * @interval: userspace pointer to the timeslice value.
4054 *
4055 * this syscall writes the default timeslice value of a given process
4056 * into the user-space timespec buffer. A value of '0' means infinity.
e69f6186
YB
4057 *
4058 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4059 * an error code.
1da177e4 4060 */
17da2bd9 4061SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
754fe8d2 4062 struct timespec __user *, interval)
1da177e4 4063{
36c8b586 4064 struct task_struct *p;
a4ec24b4 4065 unsigned int time_slice;
dba091b9
TG
4066 unsigned long flags;
4067 struct rq *rq;
3a5c359a 4068 int retval;
1da177e4 4069 struct timespec t;
1da177e4
LT
4070
4071 if (pid < 0)
3a5c359a 4072 return -EINVAL;
1da177e4
LT
4073
4074 retval = -ESRCH;
1a551ae7 4075 rcu_read_lock();
1da177e4
LT
4076 p = find_process_by_pid(pid);
4077 if (!p)
4078 goto out_unlock;
4079
4080 retval = security_task_getscheduler(p);
4081 if (retval)
4082 goto out_unlock;
4083
dba091b9
TG
4084 rq = task_rq_lock(p, &flags);
4085 time_slice = p->sched_class->get_rr_interval(rq, p);
0122ec5b 4086 task_rq_unlock(rq, p, &flags);
a4ec24b4 4087
1a551ae7 4088 rcu_read_unlock();
a4ec24b4 4089 jiffies_to_timespec(time_slice, &t);
1da177e4 4090 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
1da177e4 4091 return retval;
3a5c359a 4092
1da177e4 4093out_unlock:
1a551ae7 4094 rcu_read_unlock();
1da177e4
LT
4095 return retval;
4096}
4097
7c731e0a 4098static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
36c8b586 4099
82a1fcb9 4100void sched_show_task(struct task_struct *p)
1da177e4 4101{
1da177e4 4102 unsigned long free = 0;
4e79752c 4103 int ppid;
36c8b586 4104 unsigned state;
1da177e4 4105
1da177e4 4106 state = p->state ? __ffs(p->state) + 1 : 0;
28d0686c 4107 printk(KERN_INFO "%-15.15s %c", p->comm,
2ed6e34f 4108 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
4bd77321 4109#if BITS_PER_LONG == 32
1da177e4 4110 if (state == TASK_RUNNING)
3df0fc5b 4111 printk(KERN_CONT " running ");
1da177e4 4112 else
3df0fc5b 4113 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
1da177e4
LT
4114#else
4115 if (state == TASK_RUNNING)
3df0fc5b 4116 printk(KERN_CONT " running task ");
1da177e4 4117 else
3df0fc5b 4118 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
1da177e4
LT
4119#endif
4120#ifdef CONFIG_DEBUG_STACK_USAGE
7c9f8861 4121 free = stack_not_used(p);
1da177e4 4122#endif
4e79752c
PM
4123 rcu_read_lock();
4124 ppid = task_pid_nr(rcu_dereference(p->real_parent));
4125 rcu_read_unlock();
3df0fc5b 4126 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
4e79752c 4127 task_pid_nr(p), ppid,
aa47b7e0 4128 (unsigned long)task_thread_info(p)->flags);
1da177e4 4129
3d1cb205 4130 print_worker_info(KERN_INFO, p);
5fb5e6de 4131 show_stack(p, NULL);
1da177e4
LT
4132}
4133
e59e2ae2 4134void show_state_filter(unsigned long state_filter)
1da177e4 4135{
36c8b586 4136 struct task_struct *g, *p;
1da177e4 4137
4bd77321 4138#if BITS_PER_LONG == 32
3df0fc5b
PZ
4139 printk(KERN_INFO
4140 " task PC stack pid father\n");
1da177e4 4141#else
3df0fc5b
PZ
4142 printk(KERN_INFO
4143 " task PC stack pid father\n");
1da177e4 4144#endif
510f5acc 4145 rcu_read_lock();
1da177e4
LT
4146 do_each_thread(g, p) {
4147 /*
4148 * reset the NMI-timeout, listing all files on a slow
25985edc 4149 * console might take a lot of time:
1da177e4
LT
4150 */
4151 touch_nmi_watchdog();
39bc89fd 4152 if (!state_filter || (p->state & state_filter))
82a1fcb9 4153 sched_show_task(p);
1da177e4
LT
4154 } while_each_thread(g, p);
4155
04c9167f
JF
4156 touch_all_softlockup_watchdogs();
4157
dd41f596
IM
4158#ifdef CONFIG_SCHED_DEBUG
4159 sysrq_sched_debug_show();
4160#endif
510f5acc 4161 rcu_read_unlock();
e59e2ae2
IM
4162 /*
4163 * Only show locks if all tasks are dumped:
4164 */
93335a21 4165 if (!state_filter)
e59e2ae2 4166 debug_show_all_locks();
1da177e4
LT
4167}
4168
0db0628d 4169void init_idle_bootup_task(struct task_struct *idle)
1df21055 4170{
dd41f596 4171 idle->sched_class = &idle_sched_class;
1df21055
IM
4172}
4173
f340c0d1
IM
4174/**
4175 * init_idle - set up an idle thread for a given CPU
4176 * @idle: task in question
4177 * @cpu: cpu the idle task belongs to
4178 *
4179 * NOTE: this function does not set the idle thread's NEED_RESCHED
4180 * flag, to make booting more robust.
4181 */
0db0628d 4182void init_idle(struct task_struct *idle, int cpu)
1da177e4 4183{
70b97a7f 4184 struct rq *rq = cpu_rq(cpu);
1da177e4
LT
4185 unsigned long flags;
4186
05fa785c 4187 raw_spin_lock_irqsave(&rq->lock, flags);
5cbd54ef 4188
dd41f596 4189 __sched_fork(idle);
06b83b5f 4190 idle->state = TASK_RUNNING;
dd41f596
IM
4191 idle->se.exec_start = sched_clock();
4192
1e1b6c51 4193 do_set_cpus_allowed(idle, cpumask_of(cpu));
6506cf6c
PZ
4194 /*
4195 * We're having a chicken and egg problem, even though we are
4196 * holding rq->lock, the cpu isn't yet set to this cpu so the
4197 * lockdep check in task_group() will fail.
4198 *
4199 * Similar case to sched_fork(). / Alternatively we could
4200 * use task_rq_lock() here and obtain the other rq->lock.
4201 *
4202 * Silence PROVE_RCU
4203 */
4204 rcu_read_lock();
dd41f596 4205 __set_task_cpu(idle, cpu);
6506cf6c 4206 rcu_read_unlock();
1da177e4 4207
1da177e4 4208 rq->curr = rq->idle = idle;
3ca7a440
PZ
4209#if defined(CONFIG_SMP)
4210 idle->on_cpu = 1;
4866cde0 4211#endif
05fa785c 4212 raw_spin_unlock_irqrestore(&rq->lock, flags);
1da177e4
LT
4213
4214 /* Set the preempt count _outside_ the spinlocks! */
a1261f54 4215 task_thread_info(idle)->preempt_count = 0;
55cd5340 4216
dd41f596
IM
4217 /*
4218 * The idle tasks have their own, simple scheduling class:
4219 */
4220 idle->sched_class = &idle_sched_class;
868baf07 4221 ftrace_graph_init_idle_task(idle, cpu);
45eacc69 4222 vtime_init_idle(idle, cpu);
f1c6f1a7
CE
4223#if defined(CONFIG_SMP)
4224 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
4225#endif
19978ca6
IM
4226}
4227
1da177e4 4228#ifdef CONFIG_SMP
1e1b6c51
KM
4229void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
4230{
4231 if (p->sched_class && p->sched_class->set_cpus_allowed)
4232 p->sched_class->set_cpus_allowed(p, new_mask);
4939602a
PZ
4233
4234 cpumask_copy(&p->cpus_allowed, new_mask);
29baa747 4235 p->nr_cpus_allowed = cpumask_weight(new_mask);
1e1b6c51
KM
4236}
4237
1da177e4
LT
4238/*
4239 * This is how migration works:
4240 *
969c7921
TH
4241 * 1) we invoke migration_cpu_stop() on the target CPU using
4242 * stop_one_cpu().
4243 * 2) stopper starts to run (implicitly forcing the migrated thread
4244 * off the CPU)
4245 * 3) it checks whether the migrated task is still in the wrong runqueue.
4246 * 4) if it's in the wrong runqueue then the migration thread removes
1da177e4 4247 * it and puts it into the right queue.
969c7921
TH
4248 * 5) stopper completes and stop_one_cpu() returns and the migration
4249 * is done.
1da177e4
LT
4250 */
4251
4252/*
4253 * Change a given task's CPU affinity. Migrate the thread to a
4254 * proper CPU and schedule it away if the CPU it's executing on
4255 * is removed from the allowed bitmask.
4256 *
4257 * NOTE: the caller must have a valid reference to the task, the
41a2d6cf 4258 * task must not exit() & deallocate itself prematurely. The
1da177e4
LT
4259 * call is not atomic; no spinlocks may be held.
4260 */
96f874e2 4261int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
1da177e4
LT
4262{
4263 unsigned long flags;
70b97a7f 4264 struct rq *rq;
969c7921 4265 unsigned int dest_cpu;
48f24c4d 4266 int ret = 0;
1da177e4
LT
4267
4268 rq = task_rq_lock(p, &flags);
e2912009 4269
db44fc01
YZ
4270 if (cpumask_equal(&p->cpus_allowed, new_mask))
4271 goto out;
4272
6ad4c188 4273 if (!cpumask_intersects(new_mask, cpu_active_mask)) {
1da177e4
LT
4274 ret = -EINVAL;
4275 goto out;
4276 }
4277
1e1b6c51 4278 do_set_cpus_allowed(p, new_mask);
73fe6aae 4279
1da177e4 4280 /* Can the task run on the task's current CPU? If so, we're done */
96f874e2 4281 if (cpumask_test_cpu(task_cpu(p), new_mask))
1da177e4
LT
4282 goto out;
4283
969c7921 4284 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
bd8e7dde 4285 if (p->on_rq) {
969c7921 4286 struct migration_arg arg = { p, dest_cpu };
1da177e4 4287 /* Need help from migration thread: drop lock and wait. */
0122ec5b 4288 task_rq_unlock(rq, p, &flags);
969c7921 4289 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
1da177e4
LT
4290 tlb_migrate_finish(p->mm);
4291 return 0;
4292 }
4293out:
0122ec5b 4294 task_rq_unlock(rq, p, &flags);
48f24c4d 4295
1da177e4
LT
4296 return ret;
4297}
cd8ba7cd 4298EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
1da177e4
LT
4299
4300/*
41a2d6cf 4301 * Move (not current) task off this cpu, onto dest cpu. We're doing
1da177e4
LT
4302 * this because either it can't run here any more (set_cpus_allowed()
4303 * away from this CPU, or CPU going down), or because we're
4304 * attempting to rebalance this task on exec (sched_exec).
4305 *
4306 * So we race with normal scheduler movements, but that's OK, as long
4307 * as the task is no longer on this CPU.
efc30814
KK
4308 *
4309 * Returns non-zero if task was successfully migrated.
1da177e4 4310 */
efc30814 4311static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
1da177e4 4312{
70b97a7f 4313 struct rq *rq_dest, *rq_src;
e2912009 4314 int ret = 0;
1da177e4 4315
e761b772 4316 if (unlikely(!cpu_active(dest_cpu)))
efc30814 4317 return ret;
1da177e4
LT
4318
4319 rq_src = cpu_rq(src_cpu);
4320 rq_dest = cpu_rq(dest_cpu);
4321
0122ec5b 4322 raw_spin_lock(&p->pi_lock);
1da177e4
LT
4323 double_rq_lock(rq_src, rq_dest);
4324 /* Already moved. */
4325 if (task_cpu(p) != src_cpu)
b1e38734 4326 goto done;
1da177e4 4327 /* Affinity changed (again). */
fa17b507 4328 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
b1e38734 4329 goto fail;
1da177e4 4330
e2912009
PZ
4331 /*
4332 * If we're not on a rq, the next wake-up will ensure we're
4333 * placed properly.
4334 */
fd2f4419 4335 if (p->on_rq) {
4ca9b72b 4336 dequeue_task(rq_src, p, 0);
e2912009 4337 set_task_cpu(p, dest_cpu);
4ca9b72b 4338 enqueue_task(rq_dest, p, 0);
15afe09b 4339 check_preempt_curr(rq_dest, p, 0);
1da177e4 4340 }
b1e38734 4341done:
efc30814 4342 ret = 1;
b1e38734 4343fail:
1da177e4 4344 double_rq_unlock(rq_src, rq_dest);
0122ec5b 4345 raw_spin_unlock(&p->pi_lock);
efc30814 4346 return ret;
1da177e4
LT
4347}
4348
4349/*
969c7921
TH
4350 * migration_cpu_stop - this will be executed by a highprio stopper thread
4351 * and performs thread migration by bumping thread off CPU then
4352 * 'pushing' onto another runqueue.
1da177e4 4353 */
969c7921 4354static int migration_cpu_stop(void *data)
1da177e4 4355{
969c7921 4356 struct migration_arg *arg = data;
f7b4cddc 4357
969c7921
TH
4358 /*
4359 * The original target cpu might have gone down and we might
4360 * be on another cpu but it doesn't matter.
4361 */
f7b4cddc 4362 local_irq_disable();
969c7921 4363 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
f7b4cddc 4364 local_irq_enable();
1da177e4 4365 return 0;
f7b4cddc
ON
4366}
4367
1da177e4 4368#ifdef CONFIG_HOTPLUG_CPU
48c5ccae 4369
054b9108 4370/*
48c5ccae
PZ
4371 * Ensures that the idle task is using init_mm right before its cpu goes
4372 * offline.
054b9108 4373 */
48c5ccae 4374void idle_task_exit(void)
1da177e4 4375{
48c5ccae 4376 struct mm_struct *mm = current->active_mm;
e76bd8d9 4377
48c5ccae 4378 BUG_ON(cpu_online(smp_processor_id()));
e76bd8d9 4379
48c5ccae
PZ
4380 if (mm != &init_mm)
4381 switch_mm(mm, &init_mm, current);
4382 mmdrop(mm);
1da177e4
LT
4383}
4384
4385/*
5d180232
PZ
4386 * Since this CPU is going 'away' for a while, fold any nr_active delta
4387 * we might have. Assumes we're called after migrate_tasks() so that the
4388 * nr_active count is stable.
4389 *
4390 * Also see the comment "Global load-average calculations".
1da177e4 4391 */
5d180232 4392static void calc_load_migrate(struct rq *rq)
1da177e4 4393{
5d180232
PZ
4394 long delta = calc_load_fold_active(rq);
4395 if (delta)
4396 atomic_long_add(delta, &calc_load_tasks);
1da177e4
LT
4397}
4398
48f24c4d 4399/*
48c5ccae
PZ
4400 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4401 * try_to_wake_up()->select_task_rq().
4402 *
4403 * Called with rq->lock held even though we'er in stop_machine() and
4404 * there's no concurrency possible, we hold the required locks anyway
4405 * because of lock validation efforts.
1da177e4 4406 */
48c5ccae 4407static void migrate_tasks(unsigned int dead_cpu)
1da177e4 4408{
70b97a7f 4409 struct rq *rq = cpu_rq(dead_cpu);
48c5ccae
PZ
4410 struct task_struct *next, *stop = rq->stop;
4411 int dest_cpu;
1da177e4
LT
4412
4413 /*
48c5ccae
PZ
4414 * Fudge the rq selection such that the below task selection loop
4415 * doesn't get stuck on the currently eligible stop task.
4416 *
4417 * We're currently inside stop_machine() and the rq is either stuck
4418 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4419 * either way we should never end up calling schedule() until we're
4420 * done here.
1da177e4 4421 */
48c5ccae 4422 rq->stop = NULL;
48f24c4d 4423
77bd3970
FW
4424 /*
4425 * put_prev_task() and pick_next_task() sched
4426 * class method both need to have an up-to-date
4427 * value of rq->clock[_task]
4428 */
4429 update_rq_clock(rq);
4430
dd41f596 4431 for ( ; ; ) {
48c5ccae
PZ
4432 /*
4433 * There's this thread running, bail when that's the only
4434 * remaining thread.
4435 */
4436 if (rq->nr_running == 1)
dd41f596 4437 break;
48c5ccae 4438
b67802ea 4439 next = pick_next_task(rq);
48c5ccae 4440 BUG_ON(!next);
79c53799 4441 next->sched_class->put_prev_task(rq, next);
e692ab53 4442
48c5ccae
PZ
4443 /* Find suitable destination for @next, with force if needed. */
4444 dest_cpu = select_fallback_rq(dead_cpu, next);
4445 raw_spin_unlock(&rq->lock);
4446
4447 __migrate_task(next, dead_cpu, dest_cpu);
4448
4449 raw_spin_lock(&rq->lock);
1da177e4 4450 }
dce48a84 4451
48c5ccae 4452 rq->stop = stop;
dce48a84 4453}
48c5ccae 4454
1da177e4
LT
4455#endif /* CONFIG_HOTPLUG_CPU */
4456
e692ab53
NP
4457#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4458
4459static struct ctl_table sd_ctl_dir[] = {
e0361851
AD
4460 {
4461 .procname = "sched_domain",
c57baf1e 4462 .mode = 0555,
e0361851 4463 },
56992309 4464 {}
e692ab53
NP
4465};
4466
4467static struct ctl_table sd_ctl_root[] = {
e0361851
AD
4468 {
4469 .procname = "kernel",
c57baf1e 4470 .mode = 0555,
e0361851
AD
4471 .child = sd_ctl_dir,
4472 },
56992309 4473 {}
e692ab53
NP
4474};
4475
4476static struct ctl_table *sd_alloc_ctl_entry(int n)
4477{
4478 struct ctl_table *entry =
5cf9f062 4479 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
e692ab53 4480
e692ab53
NP
4481 return entry;
4482}
4483
6382bc90
MM
4484static void sd_free_ctl_entry(struct ctl_table **tablep)
4485{
cd790076 4486 struct ctl_table *entry;
6382bc90 4487
cd790076
MM
4488 /*
4489 * In the intermediate directories, both the child directory and
4490 * procname are dynamically allocated and could fail but the mode
41a2d6cf 4491 * will always be set. In the lowest directory the names are
cd790076
MM
4492 * static strings and all have proc handlers.
4493 */
4494 for (entry = *tablep; entry->mode; entry++) {
6382bc90
MM
4495 if (entry->child)
4496 sd_free_ctl_entry(&entry->child);
cd790076
MM
4497 if (entry->proc_handler == NULL)
4498 kfree(entry->procname);
4499 }
6382bc90
MM
4500
4501 kfree(*tablep);
4502 *tablep = NULL;
4503}
4504
201c373e 4505static int min_load_idx = 0;
fd9b86d3 4506static int max_load_idx = CPU_LOAD_IDX_MAX-1;
201c373e 4507
e692ab53 4508static void
e0361851 4509set_table_entry(struct ctl_table *entry,
e692ab53 4510 const char *procname, void *data, int maxlen,
201c373e
NK
4511 umode_t mode, proc_handler *proc_handler,
4512 bool load_idx)
e692ab53 4513{
e692ab53
NP
4514 entry->procname = procname;
4515 entry->data = data;
4516 entry->maxlen = maxlen;
4517 entry->mode = mode;
4518 entry->proc_handler = proc_handler;
201c373e
NK
4519
4520 if (load_idx) {
4521 entry->extra1 = &min_load_idx;
4522 entry->extra2 = &max_load_idx;
4523 }
e692ab53
NP
4524}
4525
4526static struct ctl_table *
4527sd_alloc_ctl_domain_table(struct sched_domain *sd)
4528{
a5d8c348 4529 struct ctl_table *table = sd_alloc_ctl_entry(13);
e692ab53 4530
ad1cdc1d
MM
4531 if (table == NULL)
4532 return NULL;
4533
e0361851 4534 set_table_entry(&table[0], "min_interval", &sd->min_interval,
201c373e 4535 sizeof(long), 0644, proc_doulongvec_minmax, false);
e0361851 4536 set_table_entry(&table[1], "max_interval", &sd->max_interval,
201c373e 4537 sizeof(long), 0644, proc_doulongvec_minmax, false);
e0361851 4538 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
201c373e 4539 sizeof(int), 0644, proc_dointvec_minmax, true);
e0361851 4540 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
201c373e 4541 sizeof(int), 0644, proc_dointvec_minmax, true);
e0361851 4542 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
201c373e 4543 sizeof(int), 0644, proc_dointvec_minmax, true);
e0361851 4544 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
201c373e 4545 sizeof(int), 0644, proc_dointvec_minmax, true);
e0361851 4546 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
201c373e 4547 sizeof(int), 0644, proc_dointvec_minmax, true);
e0361851 4548 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
201c373e 4549 sizeof(int), 0644, proc_dointvec_minmax, false);
e0361851 4550 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
201c373e 4551 sizeof(int), 0644, proc_dointvec_minmax, false);
ace8b3d6 4552 set_table_entry(&table[9], "cache_nice_tries",
e692ab53 4553 &sd->cache_nice_tries,
201c373e 4554 sizeof(int), 0644, proc_dointvec_minmax, false);
ace8b3d6 4555 set_table_entry(&table[10], "flags", &sd->flags,
201c373e 4556 sizeof(int), 0644, proc_dointvec_minmax, false);
a5d8c348 4557 set_table_entry(&table[11], "name", sd->name,
201c373e 4558 CORENAME_MAX_SIZE, 0444, proc_dostring, false);
a5d8c348 4559 /* &table[12] is terminator */
e692ab53
NP
4560
4561 return table;
4562}
4563
be7002e6 4564static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu)
e692ab53
NP
4565{
4566 struct ctl_table *entry, *table;
4567 struct sched_domain *sd;
4568 int domain_num = 0, i;
4569 char buf[32];
4570
4571 for_each_domain(cpu, sd)
4572 domain_num++;
4573 entry = table = sd_alloc_ctl_entry(domain_num + 1);
ad1cdc1d
MM
4574 if (table == NULL)
4575 return NULL;
e692ab53
NP
4576
4577 i = 0;
4578 for_each_domain(cpu, sd) {
4579 snprintf(buf, 32, "domain%d", i);
e692ab53 4580 entry->procname = kstrdup(buf, GFP_KERNEL);
c57baf1e 4581 entry->mode = 0555;
e692ab53
NP
4582 entry->child = sd_alloc_ctl_domain_table(sd);
4583 entry++;
4584 i++;
4585 }
4586 return table;
4587}
4588
4589static struct ctl_table_header *sd_sysctl_header;
6382bc90 4590static void register_sched_domain_sysctl(void)
e692ab53 4591{
6ad4c188 4592 int i, cpu_num = num_possible_cpus();
e692ab53
NP
4593 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
4594 char buf[32];
4595
7378547f
MM
4596 WARN_ON(sd_ctl_dir[0].child);
4597 sd_ctl_dir[0].child = entry;
4598
ad1cdc1d
MM
4599 if (entry == NULL)
4600 return;
4601
6ad4c188 4602 for_each_possible_cpu(i) {
e692ab53 4603 snprintf(buf, 32, "cpu%d", i);
e692ab53 4604 entry->procname = kstrdup(buf, GFP_KERNEL);
c57baf1e 4605 entry->mode = 0555;
e692ab53 4606 entry->child = sd_alloc_ctl_cpu_table(i);
97b6ea7b 4607 entry++;
e692ab53 4608 }
7378547f
MM
4609
4610 WARN_ON(sd_sysctl_header);
e692ab53
NP
4611 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
4612}
6382bc90 4613
7378547f 4614/* may be called multiple times per register */
6382bc90
MM
4615static void unregister_sched_domain_sysctl(void)
4616{
7378547f
MM
4617 if (sd_sysctl_header)
4618 unregister_sysctl_table(sd_sysctl_header);
6382bc90 4619 sd_sysctl_header = NULL;
7378547f
MM
4620 if (sd_ctl_dir[0].child)
4621 sd_free_ctl_entry(&sd_ctl_dir[0].child);
6382bc90 4622}
e692ab53 4623#else
6382bc90
MM
4624static void register_sched_domain_sysctl(void)
4625{
4626}
4627static void unregister_sched_domain_sysctl(void)
e692ab53
NP
4628{
4629}
4630#endif
4631
1f11eb6a
GH
4632static void set_rq_online(struct rq *rq)
4633{
4634 if (!rq->online) {
4635 const struct sched_class *class;
4636
c6c4927b 4637 cpumask_set_cpu(rq->cpu, rq->rd->online);
1f11eb6a
GH
4638 rq->online = 1;
4639
4640 for_each_class(class) {
4641 if (class->rq_online)
4642 class->rq_online(rq);
4643 }
4644 }
4645}
4646
4647static void set_rq_offline(struct rq *rq)
4648{
4649 if (rq->online) {
4650 const struct sched_class *class;
4651
4652 for_each_class(class) {
4653 if (class->rq_offline)
4654 class->rq_offline(rq);
4655 }
4656
c6c4927b 4657 cpumask_clear_cpu(rq->cpu, rq->rd->online);
1f11eb6a
GH
4658 rq->online = 0;
4659 }
4660}
4661
1da177e4
LT
4662/*
4663 * migration_call - callback that gets triggered when a CPU is added.
4664 * Here we can start up the necessary migration thread for the new CPU.
4665 */
0db0628d 4666static int
48f24c4d 4667migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
1da177e4 4668{
48f24c4d 4669 int cpu = (long)hcpu;
1da177e4 4670 unsigned long flags;
969c7921 4671 struct rq *rq = cpu_rq(cpu);
1da177e4 4672
48c5ccae 4673 switch (action & ~CPU_TASKS_FROZEN) {
5be9361c 4674
1da177e4 4675 case CPU_UP_PREPARE:
a468d389 4676 rq->calc_load_update = calc_load_update;
1da177e4 4677 break;
48f24c4d 4678
1da177e4 4679 case CPU_ONLINE:
1f94ef59 4680 /* Update our root-domain */
05fa785c 4681 raw_spin_lock_irqsave(&rq->lock, flags);
1f94ef59 4682 if (rq->rd) {
c6c4927b 4683 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
1f11eb6a
GH
4684
4685 set_rq_online(rq);
1f94ef59 4686 }
05fa785c 4687 raw_spin_unlock_irqrestore(&rq->lock, flags);
1da177e4 4688 break;
48f24c4d 4689
1da177e4 4690#ifdef CONFIG_HOTPLUG_CPU
08f503b0 4691 case CPU_DYING:
317f3941 4692 sched_ttwu_pending();
57d885fe 4693 /* Update our root-domain */
05fa785c 4694 raw_spin_lock_irqsave(&rq->lock, flags);
57d885fe 4695 if (rq->rd) {
c6c4927b 4696 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
1f11eb6a 4697 set_rq_offline(rq);
57d885fe 4698 }
48c5ccae
PZ
4699 migrate_tasks(cpu);
4700 BUG_ON(rq->nr_running != 1); /* the migration thread */
05fa785c 4701 raw_spin_unlock_irqrestore(&rq->lock, flags);
5d180232 4702 break;
48c5ccae 4703
5d180232 4704 case CPU_DEAD:
f319da0c 4705 calc_load_migrate(rq);
57d885fe 4706 break;
1da177e4
LT
4707#endif
4708 }
49c022e6
PZ
4709
4710 update_max_interval();
4711
1da177e4
LT
4712 return NOTIFY_OK;
4713}
4714
f38b0820
PM
4715/*
4716 * Register at high priority so that task migration (migrate_all_tasks)
4717 * happens before everything else. This has to be lower priority than
cdd6c482 4718 * the notifier in the perf_event subsystem, though.
1da177e4 4719 */
0db0628d 4720static struct notifier_block migration_notifier = {
1da177e4 4721 .notifier_call = migration_call,
50a323b7 4722 .priority = CPU_PRI_MIGRATION,
1da177e4
LT
4723};
4724
0db0628d 4725static int sched_cpu_active(struct notifier_block *nfb,
3a101d05
TH
4726 unsigned long action, void *hcpu)
4727{
4728 switch (action & ~CPU_TASKS_FROZEN) {
5fbd036b 4729 case CPU_STARTING:
3a101d05
TH
4730 case CPU_DOWN_FAILED:
4731 set_cpu_active((long)hcpu, true);
4732 return NOTIFY_OK;
4733 default:
4734 return NOTIFY_DONE;
4735 }
4736}
4737
0db0628d 4738static int sched_cpu_inactive(struct notifier_block *nfb,
3a101d05
TH
4739 unsigned long action, void *hcpu)
4740{
4741 switch (action & ~CPU_TASKS_FROZEN) {
4742 case CPU_DOWN_PREPARE:
4743 set_cpu_active((long)hcpu, false);
4744 return NOTIFY_OK;
4745 default:
4746 return NOTIFY_DONE;
4747 }
4748}
4749
7babe8db 4750static int __init migration_init(void)
1da177e4
LT
4751{
4752 void *cpu = (void *)(long)smp_processor_id();
07dccf33 4753 int err;
48f24c4d 4754
3a101d05 4755 /* Initialize migration for the boot CPU */
07dccf33
AM
4756 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
4757 BUG_ON(err == NOTIFY_BAD);
1da177e4
LT
4758 migration_call(&migration_notifier, CPU_ONLINE, cpu);
4759 register_cpu_notifier(&migration_notifier);
7babe8db 4760
3a101d05
TH
4761 /* Register cpu active notifiers */
4762 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
4763 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
4764
a004cd42 4765 return 0;
1da177e4 4766}
7babe8db 4767early_initcall(migration_init);
1da177e4
LT
4768#endif
4769
4770#ifdef CONFIG_SMP
476f3534 4771
4cb98839
PZ
4772static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
4773
3e9830dc 4774#ifdef CONFIG_SCHED_DEBUG
4dcf6aff 4775
d039ac60 4776static __read_mostly int sched_debug_enabled;
f6630114 4777
d039ac60 4778static int __init sched_debug_setup(char *str)
f6630114 4779{
d039ac60 4780 sched_debug_enabled = 1;
f6630114
MT
4781
4782 return 0;
4783}
d039ac60
PZ
4784early_param("sched_debug", sched_debug_setup);
4785
4786static inline bool sched_debug(void)
4787{
4788 return sched_debug_enabled;
4789}
f6630114 4790
7c16ec58 4791static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
96f874e2 4792 struct cpumask *groupmask)
1da177e4 4793{
4dcf6aff 4794 struct sched_group *group = sd->groups;
434d53b0 4795 char str[256];
1da177e4 4796
968ea6d8 4797 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
96f874e2 4798 cpumask_clear(groupmask);
4dcf6aff
IM
4799
4800 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
4801
4802 if (!(sd->flags & SD_LOAD_BALANCE)) {
3df0fc5b 4803 printk("does not load-balance\n");
4dcf6aff 4804 if (sd->parent)
3df0fc5b
PZ
4805 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
4806 " has parent");
4dcf6aff 4807 return -1;
41c7ce9a
NP
4808 }
4809
3df0fc5b 4810 printk(KERN_CONT "span %s level %s\n", str, sd->name);
4dcf6aff 4811
758b2cdc 4812 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
3df0fc5b
PZ
4813 printk(KERN_ERR "ERROR: domain->span does not contain "
4814 "CPU%d\n", cpu);
4dcf6aff 4815 }
758b2cdc 4816 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
3df0fc5b
PZ
4817 printk(KERN_ERR "ERROR: domain->groups does not contain"
4818 " CPU%d\n", cpu);
4dcf6aff 4819 }
1da177e4 4820
4dcf6aff 4821 printk(KERN_DEBUG "%*s groups:", level + 1, "");
1da177e4 4822 do {
4dcf6aff 4823 if (!group) {
3df0fc5b
PZ
4824 printk("\n");
4825 printk(KERN_ERR "ERROR: group is NULL\n");
1da177e4
LT
4826 break;
4827 }
4828
c3decf0d
PZ
4829 /*
4830 * Even though we initialize ->power to something semi-sane,
4831 * we leave power_orig unset. This allows us to detect if
4832 * domain iteration is still funny without causing /0 traps.
4833 */
4834 if (!group->sgp->power_orig) {
3df0fc5b
PZ
4835 printk(KERN_CONT "\n");
4836 printk(KERN_ERR "ERROR: domain->cpu_power not "
4837 "set\n");
4dcf6aff
IM
4838 break;
4839 }
1da177e4 4840
758b2cdc 4841 if (!cpumask_weight(sched_group_cpus(group))) {
3df0fc5b
PZ
4842 printk(KERN_CONT "\n");
4843 printk(KERN_ERR "ERROR: empty group\n");
4dcf6aff
IM
4844 break;
4845 }
1da177e4 4846
cb83b629
PZ
4847 if (!(sd->flags & SD_OVERLAP) &&
4848 cpumask_intersects(groupmask, sched_group_cpus(group))) {
3df0fc5b
PZ
4849 printk(KERN_CONT "\n");
4850 printk(KERN_ERR "ERROR: repeated CPUs\n");
4dcf6aff
IM
4851 break;
4852 }
1da177e4 4853
758b2cdc 4854 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
1da177e4 4855
968ea6d8 4856 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
381512cf 4857
3df0fc5b 4858 printk(KERN_CONT " %s", str);
9c3f75cb 4859 if (group->sgp->power != SCHED_POWER_SCALE) {
3df0fc5b 4860 printk(KERN_CONT " (cpu_power = %d)",
9c3f75cb 4861 group->sgp->power);
381512cf 4862 }
1da177e4 4863
4dcf6aff
IM
4864 group = group->next;
4865 } while (group != sd->groups);
3df0fc5b 4866 printk(KERN_CONT "\n");
1da177e4 4867
758b2cdc 4868 if (!cpumask_equal(sched_domain_span(sd), groupmask))
3df0fc5b 4869 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
1da177e4 4870
758b2cdc
RR
4871 if (sd->parent &&
4872 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
3df0fc5b
PZ
4873 printk(KERN_ERR "ERROR: parent span is not a superset "
4874 "of domain->span\n");
4dcf6aff
IM
4875 return 0;
4876}
1da177e4 4877
4dcf6aff
IM
4878static void sched_domain_debug(struct sched_domain *sd, int cpu)
4879{
4880 int level = 0;
1da177e4 4881
d039ac60 4882 if (!sched_debug_enabled)
f6630114
MT
4883 return;
4884
4dcf6aff
IM
4885 if (!sd) {
4886 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
4887 return;
4888 }
1da177e4 4889
4dcf6aff
IM
4890 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
4891
4892 for (;;) {
4cb98839 4893 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
4dcf6aff 4894 break;
1da177e4
LT
4895 level++;
4896 sd = sd->parent;
33859f7f 4897 if (!sd)
4dcf6aff
IM
4898 break;
4899 }
1da177e4 4900}
6d6bc0ad 4901#else /* !CONFIG_SCHED_DEBUG */
48f24c4d 4902# define sched_domain_debug(sd, cpu) do { } while (0)
d039ac60
PZ
4903static inline bool sched_debug(void)
4904{
4905 return false;
4906}
6d6bc0ad 4907#endif /* CONFIG_SCHED_DEBUG */
1da177e4 4908
1a20ff27 4909static int sd_degenerate(struct sched_domain *sd)
245af2c7 4910{
758b2cdc 4911 if (cpumask_weight(sched_domain_span(sd)) == 1)
245af2c7
SS
4912 return 1;
4913
4914 /* Following flags need at least 2 groups */
4915 if (sd->flags & (SD_LOAD_BALANCE |
4916 SD_BALANCE_NEWIDLE |
4917 SD_BALANCE_FORK |
89c4710e
SS
4918 SD_BALANCE_EXEC |
4919 SD_SHARE_CPUPOWER |
4920 SD_SHARE_PKG_RESOURCES)) {
245af2c7
SS
4921 if (sd->groups != sd->groups->next)
4922 return 0;
4923 }
4924
4925 /* Following flags don't use groups */
c88d5910 4926 if (sd->flags & (SD_WAKE_AFFINE))
245af2c7
SS
4927 return 0;
4928
4929 return 1;
4930}
4931
48f24c4d
IM
4932static int
4933sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
245af2c7
SS
4934{
4935 unsigned long cflags = sd->flags, pflags = parent->flags;
4936
4937 if (sd_degenerate(parent))
4938 return 1;
4939
758b2cdc 4940 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
245af2c7
SS
4941 return 0;
4942
245af2c7
SS
4943 /* Flags needing groups don't count if only 1 group in parent */
4944 if (parent->groups == parent->groups->next) {
4945 pflags &= ~(SD_LOAD_BALANCE |
4946 SD_BALANCE_NEWIDLE |
4947 SD_BALANCE_FORK |
89c4710e
SS
4948 SD_BALANCE_EXEC |
4949 SD_SHARE_CPUPOWER |
10866e62
PZ
4950 SD_SHARE_PKG_RESOURCES |
4951 SD_PREFER_SIBLING);
5436499e
KC
4952 if (nr_node_ids == 1)
4953 pflags &= ~SD_SERIALIZE;
245af2c7
SS
4954 }
4955 if (~cflags & pflags)
4956 return 0;
4957
4958 return 1;
4959}
4960
dce840a0 4961static void free_rootdomain(struct rcu_head *rcu)
c6c4927b 4962{
dce840a0 4963 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
047106ad 4964
68e74568 4965 cpupri_cleanup(&rd->cpupri);
c6c4927b
RR
4966 free_cpumask_var(rd->rto_mask);
4967 free_cpumask_var(rd->online);
4968 free_cpumask_var(rd->span);
4969 kfree(rd);
4970}
4971
57d885fe
GH
4972static void rq_attach_root(struct rq *rq, struct root_domain *rd)
4973{
a0490fa3 4974 struct root_domain *old_rd = NULL;
57d885fe 4975 unsigned long flags;
57d885fe 4976
05fa785c 4977 raw_spin_lock_irqsave(&rq->lock, flags);
57d885fe
GH
4978
4979 if (rq->rd) {
a0490fa3 4980 old_rd = rq->rd;
57d885fe 4981
c6c4927b 4982 if (cpumask_test_cpu(rq->cpu, old_rd->online))
1f11eb6a 4983 set_rq_offline(rq);
57d885fe 4984
c6c4927b 4985 cpumask_clear_cpu(rq->cpu, old_rd->span);
dc938520 4986
a0490fa3
IM
4987 /*
4988 * If we dont want to free the old_rt yet then
4989 * set old_rd to NULL to skip the freeing later
4990 * in this function:
4991 */
4992 if (!atomic_dec_and_test(&old_rd->refcount))
4993 old_rd = NULL;
57d885fe
GH
4994 }
4995
4996 atomic_inc(&rd->refcount);
4997 rq->rd = rd;
4998
c6c4927b 4999 cpumask_set_cpu(rq->cpu, rd->span);
00aec93d 5000 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
1f11eb6a 5001 set_rq_online(rq);
57d885fe 5002
05fa785c 5003 raw_spin_unlock_irqrestore(&rq->lock, flags);
a0490fa3
IM
5004
5005 if (old_rd)
dce840a0 5006 call_rcu_sched(&old_rd->rcu, free_rootdomain);
57d885fe
GH
5007}
5008
68c38fc3 5009static int init_rootdomain(struct root_domain *rd)
57d885fe
GH
5010{
5011 memset(rd, 0, sizeof(*rd));
5012
68c38fc3 5013 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
0c910d28 5014 goto out;
68c38fc3 5015 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
c6c4927b 5016 goto free_span;
68c38fc3 5017 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
c6c4927b 5018 goto free_online;
6e0534f2 5019
68c38fc3 5020 if (cpupri_init(&rd->cpupri) != 0)
68e74568 5021 goto free_rto_mask;
c6c4927b 5022 return 0;
6e0534f2 5023
68e74568
RR
5024free_rto_mask:
5025 free_cpumask_var(rd->rto_mask);
c6c4927b
RR
5026free_online:
5027 free_cpumask_var(rd->online);
5028free_span:
5029 free_cpumask_var(rd->span);
0c910d28 5030out:
c6c4927b 5031 return -ENOMEM;
57d885fe
GH
5032}
5033
029632fb
PZ
5034/*
5035 * By default the system creates a single root-domain with all cpus as
5036 * members (mimicking the global state we have today).
5037 */
5038struct root_domain def_root_domain;
5039
57d885fe
GH
5040static void init_defrootdomain(void)
5041{
68c38fc3 5042 init_rootdomain(&def_root_domain);
c6c4927b 5043
57d885fe
GH
5044 atomic_set(&def_root_domain.refcount, 1);
5045}
5046
dc938520 5047static struct root_domain *alloc_rootdomain(void)
57d885fe
GH
5048{
5049 struct root_domain *rd;
5050
5051 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
5052 if (!rd)
5053 return NULL;
5054
68c38fc3 5055 if (init_rootdomain(rd) != 0) {
c6c4927b
RR
5056 kfree(rd);
5057 return NULL;
5058 }
57d885fe
GH
5059
5060 return rd;
5061}
5062
e3589f6c
PZ
5063static void free_sched_groups(struct sched_group *sg, int free_sgp)
5064{
5065 struct sched_group *tmp, *first;
5066
5067 if (!sg)
5068 return;
5069
5070 first = sg;
5071 do {
5072 tmp = sg->next;
5073
5074 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref))
5075 kfree(sg->sgp);
5076
5077 kfree(sg);
5078 sg = tmp;
5079 } while (sg != first);
5080}
5081
dce840a0
PZ
5082static void free_sched_domain(struct rcu_head *rcu)
5083{
5084 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
e3589f6c
PZ
5085
5086 /*
5087 * If its an overlapping domain it has private groups, iterate and
5088 * nuke them all.
5089 */
5090 if (sd->flags & SD_OVERLAP) {
5091 free_sched_groups(sd->groups, 1);
5092 } else if (atomic_dec_and_test(&sd->groups->ref)) {
9c3f75cb 5093 kfree(sd->groups->sgp);
dce840a0 5094 kfree(sd->groups);
9c3f75cb 5095 }
dce840a0
PZ
5096 kfree(sd);
5097}
5098
5099static void destroy_sched_domain(struct sched_domain *sd, int cpu)
5100{
5101 call_rcu(&sd->rcu, free_sched_domain);
5102}
5103
5104static void destroy_sched_domains(struct sched_domain *sd, int cpu)
5105{
5106 for (; sd; sd = sd->parent)
5107 destroy_sched_domain(sd, cpu);
5108}
5109
518cd623
PZ
5110/*
5111 * Keep a special pointer to the highest sched_domain that has
5112 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5113 * allows us to avoid some pointer chasing select_idle_sibling().
5114 *
5115 * Also keep a unique ID per domain (we use the first cpu number in
5116 * the cpumask of the domain), this allows us to quickly tell if
39be3501 5117 * two cpus are in the same cache domain, see cpus_share_cache().
518cd623
PZ
5118 */
5119DEFINE_PER_CPU(struct sched_domain *, sd_llc);
7d9ffa89 5120DEFINE_PER_CPU(int, sd_llc_size);
518cd623
PZ
5121DEFINE_PER_CPU(int, sd_llc_id);
5122
5123static void update_top_cache_domain(int cpu)
5124{
5125 struct sched_domain *sd;
5126 int id = cpu;
7d9ffa89 5127 int size = 1;
518cd623
PZ
5128
5129 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
7d9ffa89 5130 if (sd) {
518cd623 5131 id = cpumask_first(sched_domain_span(sd));
7d9ffa89
PZ
5132 size = cpumask_weight(sched_domain_span(sd));
5133 }
518cd623
PZ
5134
5135 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
7d9ffa89 5136 per_cpu(sd_llc_size, cpu) = size;
518cd623
PZ
5137 per_cpu(sd_llc_id, cpu) = id;
5138}
5139
1da177e4 5140/*
0eab9146 5141 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
1da177e4
LT
5142 * hold the hotplug lock.
5143 */
0eab9146
IM
5144static void
5145cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
1da177e4 5146{
70b97a7f 5147 struct rq *rq = cpu_rq(cpu);
245af2c7
SS
5148 struct sched_domain *tmp;
5149
5150 /* Remove the sched domains which do not contribute to scheduling. */
f29c9b1c 5151 for (tmp = sd; tmp; ) {
245af2c7
SS
5152 struct sched_domain *parent = tmp->parent;
5153 if (!parent)
5154 break;
f29c9b1c 5155
1a848870 5156 if (sd_parent_degenerate(tmp, parent)) {
245af2c7 5157 tmp->parent = parent->parent;
1a848870
SS
5158 if (parent->parent)
5159 parent->parent->child = tmp;
10866e62
PZ
5160 /*
5161 * Transfer SD_PREFER_SIBLING down in case of a
5162 * degenerate parent; the spans match for this
5163 * so the property transfers.
5164 */
5165 if (parent->flags & SD_PREFER_SIBLING)
5166 tmp->flags |= SD_PREFER_SIBLING;
dce840a0 5167 destroy_sched_domain(parent, cpu);
f29c9b1c
LZ
5168 } else
5169 tmp = tmp->parent;
245af2c7
SS
5170 }
5171
1a848870 5172 if (sd && sd_degenerate(sd)) {
dce840a0 5173 tmp = sd;
245af2c7 5174 sd = sd->parent;
dce840a0 5175 destroy_sched_domain(tmp, cpu);
1a848870
SS
5176 if (sd)
5177 sd->child = NULL;
5178 }
1da177e4 5179
4cb98839 5180 sched_domain_debug(sd, cpu);
1da177e4 5181
57d885fe 5182 rq_attach_root(rq, rd);
dce840a0 5183 tmp = rq->sd;
674311d5 5184 rcu_assign_pointer(rq->sd, sd);
dce840a0 5185 destroy_sched_domains(tmp, cpu);
518cd623
PZ
5186
5187 update_top_cache_domain(cpu);
1da177e4
LT
5188}
5189
5190/* cpus with isolated domains */
dcc30a35 5191static cpumask_var_t cpu_isolated_map;
1da177e4
LT
5192
5193/* Setup the mask of cpus configured for isolated domains */
5194static int __init isolated_cpu_setup(char *str)
5195{
bdddd296 5196 alloc_bootmem_cpumask_var(&cpu_isolated_map);
968ea6d8 5197 cpulist_parse(str, cpu_isolated_map);
1da177e4
LT
5198 return 1;
5199}
5200
8927f494 5201__setup("isolcpus=", isolated_cpu_setup);
1da177e4 5202
d3081f52
PZ
5203static const struct cpumask *cpu_cpu_mask(int cpu)
5204{
5205 return cpumask_of_node(cpu_to_node(cpu));
5206}
5207
dce840a0
PZ
5208struct sd_data {
5209 struct sched_domain **__percpu sd;
5210 struct sched_group **__percpu sg;
9c3f75cb 5211 struct sched_group_power **__percpu sgp;
dce840a0
PZ
5212};
5213
49a02c51 5214struct s_data {
21d42ccf 5215 struct sched_domain ** __percpu sd;
49a02c51
AH
5216 struct root_domain *rd;
5217};
5218
2109b99e 5219enum s_alloc {
2109b99e 5220 sa_rootdomain,
21d42ccf 5221 sa_sd,
dce840a0 5222 sa_sd_storage,
2109b99e
AH
5223 sa_none,
5224};
5225
54ab4ff4
PZ
5226struct sched_domain_topology_level;
5227
5228typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
eb7a74e6
PZ
5229typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
5230
e3589f6c
PZ
5231#define SDTL_OVERLAP 0x01
5232
eb7a74e6 5233struct sched_domain_topology_level {
2c402dc3
PZ
5234 sched_domain_init_f init;
5235 sched_domain_mask_f mask;
e3589f6c 5236 int flags;
cb83b629 5237 int numa_level;
54ab4ff4 5238 struct sd_data data;
eb7a74e6
PZ
5239};
5240
c1174876
PZ
5241/*
5242 * Build an iteration mask that can exclude certain CPUs from the upwards
5243 * domain traversal.
5244 *
5245 * Asymmetric node setups can result in situations where the domain tree is of
5246 * unequal depth, make sure to skip domains that already cover the entire
5247 * range.
5248 *
5249 * In that case build_sched_domains() will have terminated the iteration early
5250 * and our sibling sd spans will be empty. Domains should always include the
5251 * cpu they're built on, so check that.
5252 *
5253 */
5254static void build_group_mask(struct sched_domain *sd, struct sched_group *sg)
5255{
5256 const struct cpumask *span = sched_domain_span(sd);
5257 struct sd_data *sdd = sd->private;
5258 struct sched_domain *sibling;
5259 int i;
5260
5261 for_each_cpu(i, span) {
5262 sibling = *per_cpu_ptr(sdd->sd, i);
5263 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
5264 continue;
5265
5266 cpumask_set_cpu(i, sched_group_mask(sg));
5267 }
5268}
5269
5270/*
5271 * Return the canonical balance cpu for this group, this is the first cpu
5272 * of this group that's also in the iteration mask.
5273 */
5274int group_balance_cpu(struct sched_group *sg)
5275{
5276 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg));
5277}
5278
e3589f6c
PZ
5279static int
5280build_overlap_sched_groups(struct sched_domain *sd, int cpu)
5281{
5282 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
5283 const struct cpumask *span = sched_domain_span(sd);
5284 struct cpumask *covered = sched_domains_tmpmask;
5285 struct sd_data *sdd = sd->private;
5286 struct sched_domain *child;
5287 int i;
5288
5289 cpumask_clear(covered);
5290
5291 for_each_cpu(i, span) {
5292 struct cpumask *sg_span;
5293
5294 if (cpumask_test_cpu(i, covered))
5295 continue;
5296
c1174876
PZ
5297 child = *per_cpu_ptr(sdd->sd, i);
5298
5299 /* See the comment near build_group_mask(). */
5300 if (!cpumask_test_cpu(i, sched_domain_span(child)))
5301 continue;
5302
e3589f6c 5303 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
4d78a223 5304 GFP_KERNEL, cpu_to_node(cpu));
e3589f6c
PZ
5305
5306 if (!sg)
5307 goto fail;
5308
5309 sg_span = sched_group_cpus(sg);
e3589f6c
PZ
5310 if (child->child) {
5311 child = child->child;
5312 cpumask_copy(sg_span, sched_domain_span(child));
5313 } else
5314 cpumask_set_cpu(i, sg_span);
5315
5316 cpumask_or(covered, covered, sg_span);
5317
74a5ce20 5318 sg->sgp = *per_cpu_ptr(sdd->sgp, i);
c1174876
PZ
5319 if (atomic_inc_return(&sg->sgp->ref) == 1)
5320 build_group_mask(sd, sg);
5321
c3decf0d
PZ
5322 /*
5323 * Initialize sgp->power such that even if we mess up the
5324 * domains and no possible iteration will get us here, we won't
5325 * die on a /0 trap.
5326 */
5327 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span);
e3589f6c 5328
c1174876
PZ
5329 /*
5330 * Make sure the first group of this domain contains the
5331 * canonical balance cpu. Otherwise the sched_domain iteration
5332 * breaks. See update_sg_lb_stats().
5333 */
74a5ce20 5334 if ((!groups && cpumask_test_cpu(cpu, sg_span)) ||
c1174876 5335 group_balance_cpu(sg) == cpu)
e3589f6c
PZ
5336 groups = sg;
5337
5338 if (!first)
5339 first = sg;
5340 if (last)
5341 last->next = sg;
5342 last = sg;
5343 last->next = first;
5344 }
5345 sd->groups = groups;
5346
5347 return 0;
5348
5349fail:
5350 free_sched_groups(first, 0);
5351
5352 return -ENOMEM;
5353}
5354
dce840a0 5355static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
1da177e4 5356{
dce840a0
PZ
5357 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
5358 struct sched_domain *child = sd->child;
1da177e4 5359
dce840a0
PZ
5360 if (child)
5361 cpu = cpumask_first(sched_domain_span(child));
1e9f28fa 5362
9c3f75cb 5363 if (sg) {
dce840a0 5364 *sg = *per_cpu_ptr(sdd->sg, cpu);
9c3f75cb 5365 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu);
e3589f6c 5366 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */
9c3f75cb 5367 }
dce840a0
PZ
5368
5369 return cpu;
1e9f28fa 5370}
1e9f28fa 5371
01a08546 5372/*
dce840a0
PZ
5373 * build_sched_groups will build a circular linked list of the groups
5374 * covered by the given span, and will set each group's ->cpumask correctly,
5375 * and ->cpu_power to 0.
e3589f6c
PZ
5376 *
5377 * Assumes the sched_domain tree is fully constructed
01a08546 5378 */
e3589f6c
PZ
5379static int
5380build_sched_groups(struct sched_domain *sd, int cpu)
1da177e4 5381{
dce840a0
PZ
5382 struct sched_group *first = NULL, *last = NULL;
5383 struct sd_data *sdd = sd->private;
5384 const struct cpumask *span = sched_domain_span(sd);
f96225fd 5385 struct cpumask *covered;
dce840a0 5386 int i;
9c1cfda2 5387
e3589f6c
PZ
5388 get_group(cpu, sdd, &sd->groups);
5389 atomic_inc(&sd->groups->ref);
5390
0936629f 5391 if (cpu != cpumask_first(span))
e3589f6c
PZ
5392 return 0;
5393
f96225fd
PZ
5394 lockdep_assert_held(&sched_domains_mutex);
5395 covered = sched_domains_tmpmask;
5396
dce840a0 5397 cpumask_clear(covered);
6711cab4 5398
dce840a0
PZ
5399 for_each_cpu(i, span) {
5400 struct sched_group *sg;
cd08e923 5401 int group, j;
6711cab4 5402
dce840a0
PZ
5403 if (cpumask_test_cpu(i, covered))
5404 continue;
6711cab4 5405
cd08e923 5406 group = get_group(i, sdd, &sg);
dce840a0 5407 cpumask_clear(sched_group_cpus(sg));
9c3f75cb 5408 sg->sgp->power = 0;
c1174876 5409 cpumask_setall(sched_group_mask(sg));
0601a88d 5410
dce840a0
PZ
5411 for_each_cpu(j, span) {
5412 if (get_group(j, sdd, NULL) != group)
5413 continue;
0601a88d 5414
dce840a0
PZ
5415 cpumask_set_cpu(j, covered);
5416 cpumask_set_cpu(j, sched_group_cpus(sg));
5417 }
0601a88d 5418
dce840a0
PZ
5419 if (!first)
5420 first = sg;
5421 if (last)
5422 last->next = sg;
5423 last = sg;
5424 }
5425 last->next = first;
e3589f6c
PZ
5426
5427 return 0;
0601a88d 5428}
51888ca2 5429
89c4710e
SS
5430/*
5431 * Initialize sched groups cpu_power.
5432 *
5433 * cpu_power indicates the capacity of sched group, which is used while
5434 * distributing the load between different sched groups in a sched domain.
5435 * Typically cpu_power for all the groups in a sched domain will be same unless
5436 * there are asymmetries in the topology. If there are asymmetries, group
5437 * having more cpu_power will pickup more load compared to the group having
5438 * less cpu_power.
89c4710e
SS
5439 */
5440static void init_sched_groups_power(int cpu, struct sched_domain *sd)
5441{
e3589f6c 5442 struct sched_group *sg = sd->groups;
89c4710e 5443
94c95ba6 5444 WARN_ON(!sg);
e3589f6c
PZ
5445
5446 do {
5447 sg->group_weight = cpumask_weight(sched_group_cpus(sg));
5448 sg = sg->next;
5449 } while (sg != sd->groups);
89c4710e 5450
c1174876 5451 if (cpu != group_balance_cpu(sg))
e3589f6c 5452 return;
aae6d3dd 5453
d274cb30 5454 update_group_power(sd, cpu);
69e1e811 5455 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
89c4710e
SS
5456}
5457
029632fb
PZ
5458int __weak arch_sd_sibling_asym_packing(void)
5459{
5460 return 0*SD_ASYM_PACKING;
89c4710e
SS
5461}
5462
7c16ec58
MT
5463/*
5464 * Initializers for schedule domains
5465 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5466 */
5467
a5d8c348
IM
5468#ifdef CONFIG_SCHED_DEBUG
5469# define SD_INIT_NAME(sd, type) sd->name = #type
5470#else
5471# define SD_INIT_NAME(sd, type) do { } while (0)
5472#endif
5473
54ab4ff4
PZ
5474#define SD_INIT_FUNC(type) \
5475static noinline struct sched_domain * \
5476sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
5477{ \
5478 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
5479 *sd = SD_##type##_INIT; \
54ab4ff4
PZ
5480 SD_INIT_NAME(sd, type); \
5481 sd->private = &tl->data; \
5482 return sd; \
7c16ec58
MT
5483}
5484
5485SD_INIT_FUNC(CPU)
7c16ec58
MT
5486#ifdef CONFIG_SCHED_SMT
5487 SD_INIT_FUNC(SIBLING)
5488#endif
5489#ifdef CONFIG_SCHED_MC
5490 SD_INIT_FUNC(MC)
5491#endif
01a08546
HC
5492#ifdef CONFIG_SCHED_BOOK
5493 SD_INIT_FUNC(BOOK)
5494#endif
7c16ec58 5495
1d3504fc 5496static int default_relax_domain_level = -1;
60495e77 5497int sched_domain_level_max;
1d3504fc
HS
5498
5499static int __init setup_relax_domain_level(char *str)
5500{
a841f8ce
DS
5501 if (kstrtoint(str, 0, &default_relax_domain_level))
5502 pr_warn("Unable to set relax_domain_level\n");
30e0e178 5503
1d3504fc
HS
5504 return 1;
5505}
5506__setup("relax_domain_level=", setup_relax_domain_level);
5507
5508static void set_domain_attribute(struct sched_domain *sd,
5509 struct sched_domain_attr *attr)
5510{
5511 int request;
5512
5513 if (!attr || attr->relax_domain_level < 0) {
5514 if (default_relax_domain_level < 0)
5515 return;
5516 else
5517 request = default_relax_domain_level;
5518 } else
5519 request = attr->relax_domain_level;
5520 if (request < sd->level) {
5521 /* turn off idle balance on this domain */
c88d5910 5522 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
1d3504fc
HS
5523 } else {
5524 /* turn on idle balance on this domain */
c88d5910 5525 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
1d3504fc
HS
5526 }
5527}
5528
54ab4ff4
PZ
5529static void __sdt_free(const struct cpumask *cpu_map);
5530static int __sdt_alloc(const struct cpumask *cpu_map);
5531
2109b99e
AH
5532static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
5533 const struct cpumask *cpu_map)
5534{
5535 switch (what) {
2109b99e 5536 case sa_rootdomain:
822ff793
PZ
5537 if (!atomic_read(&d->rd->refcount))
5538 free_rootdomain(&d->rd->rcu); /* fall through */
21d42ccf
PZ
5539 case sa_sd:
5540 free_percpu(d->sd); /* fall through */
dce840a0 5541 case sa_sd_storage:
54ab4ff4 5542 __sdt_free(cpu_map); /* fall through */
2109b99e
AH
5543 case sa_none:
5544 break;
5545 }
5546}
3404c8d9 5547
2109b99e
AH
5548static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
5549 const struct cpumask *cpu_map)
5550{
dce840a0
PZ
5551 memset(d, 0, sizeof(*d));
5552
54ab4ff4
PZ
5553 if (__sdt_alloc(cpu_map))
5554 return sa_sd_storage;
dce840a0
PZ
5555 d->sd = alloc_percpu(struct sched_domain *);
5556 if (!d->sd)
5557 return sa_sd_storage;
2109b99e 5558 d->rd = alloc_rootdomain();
dce840a0 5559 if (!d->rd)
21d42ccf 5560 return sa_sd;
2109b99e
AH
5561 return sa_rootdomain;
5562}
57d885fe 5563
dce840a0
PZ
5564/*
5565 * NULL the sd_data elements we've used to build the sched_domain and
5566 * sched_group structure so that the subsequent __free_domain_allocs()
5567 * will not free the data we're using.
5568 */
5569static void claim_allocations(int cpu, struct sched_domain *sd)
5570{
5571 struct sd_data *sdd = sd->private;
dce840a0
PZ
5572
5573 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
5574 *per_cpu_ptr(sdd->sd, cpu) = NULL;
5575
e3589f6c 5576 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
dce840a0 5577 *per_cpu_ptr(sdd->sg, cpu) = NULL;
e3589f6c
PZ
5578
5579 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref))
9c3f75cb 5580 *per_cpu_ptr(sdd->sgp, cpu) = NULL;
dce840a0
PZ
5581}
5582
2c402dc3
PZ
5583#ifdef CONFIG_SCHED_SMT
5584static const struct cpumask *cpu_smt_mask(int cpu)
7f4588f3 5585{
2c402dc3 5586 return topology_thread_cpumask(cpu);
3bd65a80 5587}
2c402dc3 5588#endif
7f4588f3 5589
d069b916
PZ
5590/*
5591 * Topology list, bottom-up.
5592 */
2c402dc3 5593static struct sched_domain_topology_level default_topology[] = {
d069b916
PZ
5594#ifdef CONFIG_SCHED_SMT
5595 { sd_init_SIBLING, cpu_smt_mask, },
01a08546 5596#endif
1e9f28fa 5597#ifdef CONFIG_SCHED_MC
2c402dc3 5598 { sd_init_MC, cpu_coregroup_mask, },
1e9f28fa 5599#endif
d069b916
PZ
5600#ifdef CONFIG_SCHED_BOOK
5601 { sd_init_BOOK, cpu_book_mask, },
5602#endif
5603 { sd_init_CPU, cpu_cpu_mask, },
eb7a74e6
PZ
5604 { NULL, },
5605};
5606
5607static struct sched_domain_topology_level *sched_domain_topology = default_topology;
5608
27723a68
VK
5609#define for_each_sd_topology(tl) \
5610 for (tl = sched_domain_topology; tl->init; tl++)
5611
cb83b629
PZ
5612#ifdef CONFIG_NUMA
5613
5614static int sched_domains_numa_levels;
cb83b629
PZ
5615static int *sched_domains_numa_distance;
5616static struct cpumask ***sched_domains_numa_masks;
5617static int sched_domains_curr_level;
5618
cb83b629
PZ
5619static inline int sd_local_flags(int level)
5620{
10717dcd 5621 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE)
cb83b629
PZ
5622 return 0;
5623
5624 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE;
5625}
5626
5627static struct sched_domain *
5628sd_numa_init(struct sched_domain_topology_level *tl, int cpu)
5629{
5630 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
5631 int level = tl->numa_level;
5632 int sd_weight = cpumask_weight(
5633 sched_domains_numa_masks[level][cpu_to_node(cpu)]);
5634
5635 *sd = (struct sched_domain){
5636 .min_interval = sd_weight,
5637 .max_interval = 2*sd_weight,
5638 .busy_factor = 32,
870a0bb5 5639 .imbalance_pct = 125,
cb83b629
PZ
5640 .cache_nice_tries = 2,
5641 .busy_idx = 3,
5642 .idle_idx = 2,
5643 .newidle_idx = 0,
5644 .wake_idx = 0,
5645 .forkexec_idx = 0,
5646
5647 .flags = 1*SD_LOAD_BALANCE
5648 | 1*SD_BALANCE_NEWIDLE
5649 | 0*SD_BALANCE_EXEC
5650 | 0*SD_BALANCE_FORK
5651 | 0*SD_BALANCE_WAKE
5652 | 0*SD_WAKE_AFFINE
cb83b629 5653 | 0*SD_SHARE_CPUPOWER
cb83b629
PZ
5654 | 0*SD_SHARE_PKG_RESOURCES
5655 | 1*SD_SERIALIZE
5656 | 0*SD_PREFER_SIBLING
5657 | sd_local_flags(level)
5658 ,
5659 .last_balance = jiffies,
5660 .balance_interval = sd_weight,
5661 };
5662 SD_INIT_NAME(sd, NUMA);
5663 sd->private = &tl->data;
5664
5665 /*
5666 * Ugly hack to pass state to sd_numa_mask()...
5667 */
5668 sched_domains_curr_level = tl->numa_level;
5669
5670 return sd;
5671}
5672
5673static const struct cpumask *sd_numa_mask(int cpu)
5674{
5675 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
5676}
5677
d039ac60
PZ
5678static void sched_numa_warn(const char *str)
5679{
5680 static int done = false;
5681 int i,j;
5682
5683 if (done)
5684 return;
5685
5686 done = true;
5687
5688 printk(KERN_WARNING "ERROR: %s\n\n", str);
5689
5690 for (i = 0; i < nr_node_ids; i++) {
5691 printk(KERN_WARNING " ");
5692 for (j = 0; j < nr_node_ids; j++)
5693 printk(KERN_CONT "%02d ", node_distance(i,j));
5694 printk(KERN_CONT "\n");
5695 }
5696 printk(KERN_WARNING "\n");
5697}
5698
5699static bool find_numa_distance(int distance)
5700{
5701 int i;
5702
5703 if (distance == node_distance(0, 0))
5704 return true;
5705
5706 for (i = 0; i < sched_domains_numa_levels; i++) {
5707 if (sched_domains_numa_distance[i] == distance)
5708 return true;
5709 }
5710
5711 return false;
5712}
5713
cb83b629
PZ
5714static void sched_init_numa(void)
5715{
5716 int next_distance, curr_distance = node_distance(0, 0);
5717 struct sched_domain_topology_level *tl;
5718 int level = 0;
5719 int i, j, k;
5720
cb83b629
PZ
5721 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL);
5722 if (!sched_domains_numa_distance)
5723 return;
5724
5725 /*
5726 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
5727 * unique distances in the node_distance() table.
5728 *
5729 * Assumes node_distance(0,j) includes all distances in
5730 * node_distance(i,j) in order to avoid cubic time.
cb83b629
PZ
5731 */
5732 next_distance = curr_distance;
5733 for (i = 0; i < nr_node_ids; i++) {
5734 for (j = 0; j < nr_node_ids; j++) {
d039ac60
PZ
5735 for (k = 0; k < nr_node_ids; k++) {
5736 int distance = node_distance(i, k);
5737
5738 if (distance > curr_distance &&
5739 (distance < next_distance ||
5740 next_distance == curr_distance))
5741 next_distance = distance;
5742
5743 /*
5744 * While not a strong assumption it would be nice to know
5745 * about cases where if node A is connected to B, B is not
5746 * equally connected to A.
5747 */
5748 if (sched_debug() && node_distance(k, i) != distance)
5749 sched_numa_warn("Node-distance not symmetric");
5750
5751 if (sched_debug() && i && !find_numa_distance(distance))
5752 sched_numa_warn("Node-0 not representative");
5753 }
5754 if (next_distance != curr_distance) {
5755 sched_domains_numa_distance[level++] = next_distance;
5756 sched_domains_numa_levels = level;
5757 curr_distance = next_distance;
5758 } else break;
cb83b629 5759 }
d039ac60
PZ
5760
5761 /*
5762 * In case of sched_debug() we verify the above assumption.
5763 */
5764 if (!sched_debug())
5765 break;
cb83b629
PZ
5766 }
5767 /*
5768 * 'level' contains the number of unique distances, excluding the
5769 * identity distance node_distance(i,i).
5770 *
28b4a521 5771 * The sched_domains_numa_distance[] array includes the actual distance
cb83b629
PZ
5772 * numbers.
5773 */
5774
5f7865f3
TC
5775 /*
5776 * Here, we should temporarily reset sched_domains_numa_levels to 0.
5777 * If it fails to allocate memory for array sched_domains_numa_masks[][],
5778 * the array will contain less then 'level' members. This could be
5779 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
5780 * in other functions.
5781 *
5782 * We reset it to 'level' at the end of this function.
5783 */
5784 sched_domains_numa_levels = 0;
5785
cb83b629
PZ
5786 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
5787 if (!sched_domains_numa_masks)
5788 return;
5789
5790 /*
5791 * Now for each level, construct a mask per node which contains all
5792 * cpus of nodes that are that many hops away from us.
5793 */
5794 for (i = 0; i < level; i++) {
5795 sched_domains_numa_masks[i] =
5796 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
5797 if (!sched_domains_numa_masks[i])
5798 return;
5799
5800 for (j = 0; j < nr_node_ids; j++) {
2ea45800 5801 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
cb83b629
PZ
5802 if (!mask)
5803 return;
5804
5805 sched_domains_numa_masks[i][j] = mask;
5806
5807 for (k = 0; k < nr_node_ids; k++) {
dd7d8634 5808 if (node_distance(j, k) > sched_domains_numa_distance[i])
cb83b629
PZ
5809 continue;
5810
5811 cpumask_or(mask, mask, cpumask_of_node(k));
5812 }
5813 }
5814 }
5815
5816 tl = kzalloc((ARRAY_SIZE(default_topology) + level) *
5817 sizeof(struct sched_domain_topology_level), GFP_KERNEL);
5818 if (!tl)
5819 return;
5820
5821 /*
5822 * Copy the default topology bits..
5823 */
5824 for (i = 0; default_topology[i].init; i++)
5825 tl[i] = default_topology[i];
5826
5827 /*
5828 * .. and append 'j' levels of NUMA goodness.
5829 */
5830 for (j = 0; j < level; i++, j++) {
5831 tl[i] = (struct sched_domain_topology_level){
5832 .init = sd_numa_init,
5833 .mask = sd_numa_mask,
5834 .flags = SDTL_OVERLAP,
5835 .numa_level = j,
5836 };
5837 }
5838
5839 sched_domain_topology = tl;
5f7865f3
TC
5840
5841 sched_domains_numa_levels = level;
cb83b629 5842}
301a5cba
TC
5843
5844static void sched_domains_numa_masks_set(int cpu)
5845{
5846 int i, j;
5847 int node = cpu_to_node(cpu);
5848
5849 for (i = 0; i < sched_domains_numa_levels; i++) {
5850 for (j = 0; j < nr_node_ids; j++) {
5851 if (node_distance(j, node) <= sched_domains_numa_distance[i])
5852 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
5853 }
5854 }
5855}
5856
5857static void sched_domains_numa_masks_clear(int cpu)
5858{
5859 int i, j;
5860 for (i = 0; i < sched_domains_numa_levels; i++) {
5861 for (j = 0; j < nr_node_ids; j++)
5862 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
5863 }
5864}
5865
5866/*
5867 * Update sched_domains_numa_masks[level][node] array when new cpus
5868 * are onlined.
5869 */
5870static int sched_domains_numa_masks_update(struct notifier_block *nfb,
5871 unsigned long action,
5872 void *hcpu)
5873{
5874 int cpu = (long)hcpu;
5875
5876 switch (action & ~CPU_TASKS_FROZEN) {
5877 case CPU_ONLINE:
5878 sched_domains_numa_masks_set(cpu);
5879 break;
5880
5881 case CPU_DEAD:
5882 sched_domains_numa_masks_clear(cpu);
5883 break;
5884
5885 default:
5886 return NOTIFY_DONE;
5887 }
5888
5889 return NOTIFY_OK;
cb83b629
PZ
5890}
5891#else
5892static inline void sched_init_numa(void)
5893{
5894}
301a5cba
TC
5895
5896static int sched_domains_numa_masks_update(struct notifier_block *nfb,
5897 unsigned long action,
5898 void *hcpu)
5899{
5900 return 0;
5901}
cb83b629
PZ
5902#endif /* CONFIG_NUMA */
5903
54ab4ff4
PZ
5904static int __sdt_alloc(const struct cpumask *cpu_map)
5905{
5906 struct sched_domain_topology_level *tl;
5907 int j;
5908
27723a68 5909 for_each_sd_topology(tl) {
54ab4ff4
PZ
5910 struct sd_data *sdd = &tl->data;
5911
5912 sdd->sd = alloc_percpu(struct sched_domain *);
5913 if (!sdd->sd)
5914 return -ENOMEM;
5915
5916 sdd->sg = alloc_percpu(struct sched_group *);
5917 if (!sdd->sg)
5918 return -ENOMEM;
5919
9c3f75cb
PZ
5920 sdd->sgp = alloc_percpu(struct sched_group_power *);
5921 if (!sdd->sgp)
5922 return -ENOMEM;
5923
54ab4ff4
PZ
5924 for_each_cpu(j, cpu_map) {
5925 struct sched_domain *sd;
5926 struct sched_group *sg;
9c3f75cb 5927 struct sched_group_power *sgp;
54ab4ff4
PZ
5928
5929 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
5930 GFP_KERNEL, cpu_to_node(j));
5931 if (!sd)
5932 return -ENOMEM;
5933
5934 *per_cpu_ptr(sdd->sd, j) = sd;
5935
5936 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
5937 GFP_KERNEL, cpu_to_node(j));
5938 if (!sg)
5939 return -ENOMEM;
5940
30b4e9eb
IM
5941 sg->next = sg;
5942
54ab4ff4 5943 *per_cpu_ptr(sdd->sg, j) = sg;
9c3f75cb 5944
c1174876 5945 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(),
9c3f75cb
PZ
5946 GFP_KERNEL, cpu_to_node(j));
5947 if (!sgp)
5948 return -ENOMEM;
5949
5950 *per_cpu_ptr(sdd->sgp, j) = sgp;
54ab4ff4
PZ
5951 }
5952 }
5953
5954 return 0;
5955}
5956
5957static void __sdt_free(const struct cpumask *cpu_map)
5958{
5959 struct sched_domain_topology_level *tl;
5960 int j;
5961
27723a68 5962 for_each_sd_topology(tl) {
54ab4ff4
PZ
5963 struct sd_data *sdd = &tl->data;
5964
5965 for_each_cpu(j, cpu_map) {
fb2cf2c6 5966 struct sched_domain *sd;
5967
5968 if (sdd->sd) {
5969 sd = *per_cpu_ptr(sdd->sd, j);
5970 if (sd && (sd->flags & SD_OVERLAP))
5971 free_sched_groups(sd->groups, 0);
5972 kfree(*per_cpu_ptr(sdd->sd, j));
5973 }
5974
5975 if (sdd->sg)
5976 kfree(*per_cpu_ptr(sdd->sg, j));
5977 if (sdd->sgp)
5978 kfree(*per_cpu_ptr(sdd->sgp, j));
54ab4ff4
PZ
5979 }
5980 free_percpu(sdd->sd);
fb2cf2c6 5981 sdd->sd = NULL;
54ab4ff4 5982 free_percpu(sdd->sg);
fb2cf2c6 5983 sdd->sg = NULL;
9c3f75cb 5984 free_percpu(sdd->sgp);
fb2cf2c6 5985 sdd->sgp = NULL;
54ab4ff4
PZ
5986 }
5987}
5988
2c402dc3 5989struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
4a850cbe
VK
5990 const struct cpumask *cpu_map, struct sched_domain_attr *attr,
5991 struct sched_domain *child, int cpu)
2c402dc3 5992{
54ab4ff4 5993 struct sched_domain *sd = tl->init(tl, cpu);
2c402dc3 5994 if (!sd)
d069b916 5995 return child;
2c402dc3 5996
2c402dc3 5997 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
60495e77
PZ
5998 if (child) {
5999 sd->level = child->level + 1;
6000 sched_domain_level_max = max(sched_domain_level_max, sd->level);
d069b916 6001 child->parent = sd;
c75e0128 6002 sd->child = child;
60495e77 6003 }
a841f8ce 6004 set_domain_attribute(sd, attr);
2c402dc3
PZ
6005
6006 return sd;
6007}
6008
2109b99e
AH
6009/*
6010 * Build sched domains for a given set of cpus and attach the sched domains
6011 * to the individual cpus
6012 */
dce840a0
PZ
6013static int build_sched_domains(const struct cpumask *cpu_map,
6014 struct sched_domain_attr *attr)
2109b99e 6015{
1c632169 6016 enum s_alloc alloc_state;
dce840a0 6017 struct sched_domain *sd;
2109b99e 6018 struct s_data d;
822ff793 6019 int i, ret = -ENOMEM;
9c1cfda2 6020
2109b99e
AH
6021 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
6022 if (alloc_state != sa_rootdomain)
6023 goto error;
9c1cfda2 6024
dce840a0 6025 /* Set up domains for cpus specified by the cpu_map. */
abcd083a 6026 for_each_cpu(i, cpu_map) {
eb7a74e6
PZ
6027 struct sched_domain_topology_level *tl;
6028
3bd65a80 6029 sd = NULL;
27723a68 6030 for_each_sd_topology(tl) {
4a850cbe 6031 sd = build_sched_domain(tl, cpu_map, attr, sd, i);
22da9569
VK
6032 if (tl == sched_domain_topology)
6033 *per_cpu_ptr(d.sd, i) = sd;
e3589f6c
PZ
6034 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
6035 sd->flags |= SD_OVERLAP;
d110235d
PZ
6036 if (cpumask_equal(cpu_map, sched_domain_span(sd)))
6037 break;
e3589f6c 6038 }
dce840a0
PZ
6039 }
6040
6041 /* Build the groups for the domains */
6042 for_each_cpu(i, cpu_map) {
6043 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6044 sd->span_weight = cpumask_weight(sched_domain_span(sd));
e3589f6c
PZ
6045 if (sd->flags & SD_OVERLAP) {
6046 if (build_overlap_sched_groups(sd, i))
6047 goto error;
6048 } else {
6049 if (build_sched_groups(sd, i))
6050 goto error;
6051 }
1cf51902 6052 }
a06dadbe 6053 }
9c1cfda2 6054
1da177e4 6055 /* Calculate CPU power for physical packages and nodes */
a9c9a9b6
PZ
6056 for (i = nr_cpumask_bits-1; i >= 0; i--) {
6057 if (!cpumask_test_cpu(i, cpu_map))
6058 continue;
9c1cfda2 6059
dce840a0
PZ
6060 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6061 claim_allocations(i, sd);
cd4ea6ae 6062 init_sched_groups_power(i, sd);
dce840a0 6063 }
f712c0c7 6064 }
9c1cfda2 6065
1da177e4 6066 /* Attach the domains */
dce840a0 6067 rcu_read_lock();
abcd083a 6068 for_each_cpu(i, cpu_map) {
21d42ccf 6069 sd = *per_cpu_ptr(d.sd, i);
49a02c51 6070 cpu_attach_domain(sd, d.rd, i);
1da177e4 6071 }
dce840a0 6072 rcu_read_unlock();
51888ca2 6073
822ff793 6074 ret = 0;
51888ca2 6075error:
2109b99e 6076 __free_domain_allocs(&d, alloc_state, cpu_map);
822ff793 6077 return ret;
1da177e4 6078}
029190c5 6079
acc3f5d7 6080static cpumask_var_t *doms_cur; /* current sched domains */
029190c5 6081static int ndoms_cur; /* number of sched domains in 'doms_cur' */
4285f594
IM
6082static struct sched_domain_attr *dattr_cur;
6083 /* attribues of custom domains in 'doms_cur' */
029190c5
PJ
6084
6085/*
6086 * Special case: If a kmalloc of a doms_cur partition (array of
4212823f
RR
6087 * cpumask) fails, then fallback to a single sched domain,
6088 * as determined by the single cpumask fallback_doms.
029190c5 6089 */
4212823f 6090static cpumask_var_t fallback_doms;
029190c5 6091
ee79d1bd
HC
6092/*
6093 * arch_update_cpu_topology lets virtualized architectures update the
6094 * cpu core maps. It is supposed to return 1 if the topology changed
6095 * or 0 if it stayed the same.
6096 */
6097int __attribute__((weak)) arch_update_cpu_topology(void)
22e52b07 6098{
ee79d1bd 6099 return 0;
22e52b07
HC
6100}
6101
acc3f5d7
RR
6102cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
6103{
6104 int i;
6105 cpumask_var_t *doms;
6106
6107 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
6108 if (!doms)
6109 return NULL;
6110 for (i = 0; i < ndoms; i++) {
6111 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
6112 free_sched_domains(doms, i);
6113 return NULL;
6114 }
6115 }
6116 return doms;
6117}
6118
6119void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
6120{
6121 unsigned int i;
6122 for (i = 0; i < ndoms; i++)
6123 free_cpumask_var(doms[i]);
6124 kfree(doms);
6125}
6126
1a20ff27 6127/*
41a2d6cf 6128 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
029190c5
PJ
6129 * For now this just excludes isolated cpus, but could be used to
6130 * exclude other special cases in the future.
1a20ff27 6131 */
c4a8849a 6132static int init_sched_domains(const struct cpumask *cpu_map)
1a20ff27 6133{
7378547f
MM
6134 int err;
6135
22e52b07 6136 arch_update_cpu_topology();
029190c5 6137 ndoms_cur = 1;
acc3f5d7 6138 doms_cur = alloc_sched_domains(ndoms_cur);
029190c5 6139 if (!doms_cur)
acc3f5d7
RR
6140 doms_cur = &fallback_doms;
6141 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
dce840a0 6142 err = build_sched_domains(doms_cur[0], NULL);
6382bc90 6143 register_sched_domain_sysctl();
7378547f
MM
6144
6145 return err;
1a20ff27
DG
6146}
6147
1a20ff27
DG
6148/*
6149 * Detach sched domains from a group of cpus specified in cpu_map
6150 * These cpus will now be attached to the NULL domain
6151 */
96f874e2 6152static void detach_destroy_domains(const struct cpumask *cpu_map)
1a20ff27
DG
6153{
6154 int i;
6155
dce840a0 6156 rcu_read_lock();
abcd083a 6157 for_each_cpu(i, cpu_map)
57d885fe 6158 cpu_attach_domain(NULL, &def_root_domain, i);
dce840a0 6159 rcu_read_unlock();
1a20ff27
DG
6160}
6161
1d3504fc
HS
6162/* handle null as "default" */
6163static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
6164 struct sched_domain_attr *new, int idx_new)
6165{
6166 struct sched_domain_attr tmp;
6167
6168 /* fast path */
6169 if (!new && !cur)
6170 return 1;
6171
6172 tmp = SD_ATTR_INIT;
6173 return !memcmp(cur ? (cur + idx_cur) : &tmp,
6174 new ? (new + idx_new) : &tmp,
6175 sizeof(struct sched_domain_attr));
6176}
6177
029190c5
PJ
6178/*
6179 * Partition sched domains as specified by the 'ndoms_new'
41a2d6cf 6180 * cpumasks in the array doms_new[] of cpumasks. This compares
029190c5
PJ
6181 * doms_new[] to the current sched domain partitioning, doms_cur[].
6182 * It destroys each deleted domain and builds each new domain.
6183 *
acc3f5d7 6184 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
41a2d6cf
IM
6185 * The masks don't intersect (don't overlap.) We should setup one
6186 * sched domain for each mask. CPUs not in any of the cpumasks will
6187 * not be load balanced. If the same cpumask appears both in the
029190c5
PJ
6188 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6189 * it as it is.
6190 *
acc3f5d7
RR
6191 * The passed in 'doms_new' should be allocated using
6192 * alloc_sched_domains. This routine takes ownership of it and will
6193 * free_sched_domains it when done with it. If the caller failed the
6194 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6195 * and partition_sched_domains() will fallback to the single partition
6196 * 'fallback_doms', it also forces the domains to be rebuilt.
029190c5 6197 *
96f874e2 6198 * If doms_new == NULL it will be replaced with cpu_online_mask.
700018e0
LZ
6199 * ndoms_new == 0 is a special case for destroying existing domains,
6200 * and it will not create the default domain.
dfb512ec 6201 *
029190c5
PJ
6202 * Call with hotplug lock held
6203 */
acc3f5d7 6204void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
1d3504fc 6205 struct sched_domain_attr *dattr_new)
029190c5 6206{
dfb512ec 6207 int i, j, n;
d65bd5ec 6208 int new_topology;
029190c5 6209
712555ee 6210 mutex_lock(&sched_domains_mutex);
a1835615 6211
7378547f
MM
6212 /* always unregister in case we don't destroy any domains */
6213 unregister_sched_domain_sysctl();
6214
d65bd5ec
HC
6215 /* Let architecture update cpu core mappings. */
6216 new_topology = arch_update_cpu_topology();
6217
dfb512ec 6218 n = doms_new ? ndoms_new : 0;
029190c5
PJ
6219
6220 /* Destroy deleted domains */
6221 for (i = 0; i < ndoms_cur; i++) {
d65bd5ec 6222 for (j = 0; j < n && !new_topology; j++) {
acc3f5d7 6223 if (cpumask_equal(doms_cur[i], doms_new[j])
1d3504fc 6224 && dattrs_equal(dattr_cur, i, dattr_new, j))
029190c5
PJ
6225 goto match1;
6226 }
6227 /* no match - a current sched domain not in new doms_new[] */
acc3f5d7 6228 detach_destroy_domains(doms_cur[i]);
029190c5
PJ
6229match1:
6230 ;
6231 }
6232
c8d2d47a 6233 n = ndoms_cur;
e761b772 6234 if (doms_new == NULL) {
c8d2d47a 6235 n = 0;
acc3f5d7 6236 doms_new = &fallback_doms;
6ad4c188 6237 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
faa2f98f 6238 WARN_ON_ONCE(dattr_new);
e761b772
MK
6239 }
6240
029190c5
PJ
6241 /* Build new domains */
6242 for (i = 0; i < ndoms_new; i++) {
c8d2d47a 6243 for (j = 0; j < n && !new_topology; j++) {
acc3f5d7 6244 if (cpumask_equal(doms_new[i], doms_cur[j])
1d3504fc 6245 && dattrs_equal(dattr_new, i, dattr_cur, j))
029190c5
PJ
6246 goto match2;
6247 }
6248 /* no match - add a new doms_new */
dce840a0 6249 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
029190c5
PJ
6250match2:
6251 ;
6252 }
6253
6254 /* Remember the new sched domains */
acc3f5d7
RR
6255 if (doms_cur != &fallback_doms)
6256 free_sched_domains(doms_cur, ndoms_cur);
1d3504fc 6257 kfree(dattr_cur); /* kfree(NULL) is safe */
029190c5 6258 doms_cur = doms_new;
1d3504fc 6259 dattr_cur = dattr_new;
029190c5 6260 ndoms_cur = ndoms_new;
7378547f
MM
6261
6262 register_sched_domain_sysctl();
a1835615 6263
712555ee 6264 mutex_unlock(&sched_domains_mutex);
029190c5
PJ
6265}
6266
d35be8ba
SB
6267static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */
6268
1da177e4 6269/*
3a101d05
TH
6270 * Update cpusets according to cpu_active mask. If cpusets are
6271 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6272 * around partition_sched_domains().
d35be8ba
SB
6273 *
6274 * If we come here as part of a suspend/resume, don't touch cpusets because we
6275 * want to restore it back to its original state upon resume anyway.
1da177e4 6276 */
0b2e918a
TH
6277static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
6278 void *hcpu)
e761b772 6279{
d35be8ba
SB
6280 switch (action) {
6281 case CPU_ONLINE_FROZEN:
6282 case CPU_DOWN_FAILED_FROZEN:
6283
6284 /*
6285 * num_cpus_frozen tracks how many CPUs are involved in suspend
6286 * resume sequence. As long as this is not the last online
6287 * operation in the resume sequence, just build a single sched
6288 * domain, ignoring cpusets.
6289 */
6290 num_cpus_frozen--;
6291 if (likely(num_cpus_frozen)) {
6292 partition_sched_domains(1, NULL, NULL);
6293 break;
6294 }
6295
6296 /*
6297 * This is the last CPU online operation. So fall through and
6298 * restore the original sched domains by considering the
6299 * cpuset configurations.
6300 */
6301
e761b772 6302 case CPU_ONLINE:
6ad4c188 6303 case CPU_DOWN_FAILED:
7ddf96b0 6304 cpuset_update_active_cpus(true);
d35be8ba 6305 break;
3a101d05
TH
6306 default:
6307 return NOTIFY_DONE;
6308 }
d35be8ba 6309 return NOTIFY_OK;
3a101d05 6310}
e761b772 6311
0b2e918a
TH
6312static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
6313 void *hcpu)
3a101d05 6314{
d35be8ba 6315 switch (action) {
3a101d05 6316 case CPU_DOWN_PREPARE:
7ddf96b0 6317 cpuset_update_active_cpus(false);
d35be8ba
SB
6318 break;
6319 case CPU_DOWN_PREPARE_FROZEN:
6320 num_cpus_frozen++;
6321 partition_sched_domains(1, NULL, NULL);
6322 break;
e761b772
MK
6323 default:
6324 return NOTIFY_DONE;
6325 }
d35be8ba 6326 return NOTIFY_OK;
e761b772 6327}
e761b772 6328
1da177e4
LT
6329void __init sched_init_smp(void)
6330{
dcc30a35
RR
6331 cpumask_var_t non_isolated_cpus;
6332
6333 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
cb5fd13f 6334 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
5c1e1767 6335
cb83b629
PZ
6336 sched_init_numa();
6337
95402b38 6338 get_online_cpus();
712555ee 6339 mutex_lock(&sched_domains_mutex);
c4a8849a 6340 init_sched_domains(cpu_active_mask);
dcc30a35
RR
6341 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
6342 if (cpumask_empty(non_isolated_cpus))
6343 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
712555ee 6344 mutex_unlock(&sched_domains_mutex);
95402b38 6345 put_online_cpus();
e761b772 6346
301a5cba 6347 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
3a101d05
TH
6348 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
6349 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
e761b772 6350
b328ca18 6351 init_hrtick();
5c1e1767
NP
6352
6353 /* Move init over to a non-isolated CPU */
dcc30a35 6354 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
5c1e1767 6355 BUG();
19978ca6 6356 sched_init_granularity();
dcc30a35 6357 free_cpumask_var(non_isolated_cpus);
4212823f 6358
0e3900e6 6359 init_sched_rt_class();
1da177e4
LT
6360}
6361#else
6362void __init sched_init_smp(void)
6363{
19978ca6 6364 sched_init_granularity();
1da177e4
LT
6365}
6366#endif /* CONFIG_SMP */
6367
cd1bb94b
AB
6368const_debug unsigned int sysctl_timer_migration = 1;
6369
1da177e4
LT
6370int in_sched_functions(unsigned long addr)
6371{
1da177e4
LT
6372 return in_lock_functions(addr) ||
6373 (addr >= (unsigned long)__sched_text_start
6374 && addr < (unsigned long)__sched_text_end);
6375}
6376
029632fb 6377#ifdef CONFIG_CGROUP_SCHED
27b4b931
LZ
6378/*
6379 * Default task group.
6380 * Every task in system belongs to this group at bootup.
6381 */
029632fb 6382struct task_group root_task_group;
35cf4e50 6383LIST_HEAD(task_groups);
052f1dc7 6384#endif
6f505b16 6385
e6252c3e 6386DECLARE_PER_CPU(cpumask_var_t, load_balance_mask);
6f505b16 6387
1da177e4
LT
6388void __init sched_init(void)
6389{
dd41f596 6390 int i, j;
434d53b0
MT
6391 unsigned long alloc_size = 0, ptr;
6392
6393#ifdef CONFIG_FAIR_GROUP_SCHED
6394 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
6395#endif
6396#ifdef CONFIG_RT_GROUP_SCHED
6397 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
eff766a6 6398#endif
df7c8e84 6399#ifdef CONFIG_CPUMASK_OFFSTACK
8c083f08 6400 alloc_size += num_possible_cpus() * cpumask_size();
434d53b0 6401#endif
434d53b0 6402 if (alloc_size) {
36b7b6d4 6403 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
434d53b0
MT
6404
6405#ifdef CONFIG_FAIR_GROUP_SCHED
07e06b01 6406 root_task_group.se = (struct sched_entity **)ptr;
434d53b0
MT
6407 ptr += nr_cpu_ids * sizeof(void **);
6408
07e06b01 6409 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
434d53b0 6410 ptr += nr_cpu_ids * sizeof(void **);
eff766a6 6411
6d6bc0ad 6412#endif /* CONFIG_FAIR_GROUP_SCHED */
434d53b0 6413#ifdef CONFIG_RT_GROUP_SCHED
07e06b01 6414 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
434d53b0
MT
6415 ptr += nr_cpu_ids * sizeof(void **);
6416
07e06b01 6417 root_task_group.rt_rq = (struct rt_rq **)ptr;
eff766a6
PZ
6418 ptr += nr_cpu_ids * sizeof(void **);
6419
6d6bc0ad 6420#endif /* CONFIG_RT_GROUP_SCHED */
df7c8e84
RR
6421#ifdef CONFIG_CPUMASK_OFFSTACK
6422 for_each_possible_cpu(i) {
e6252c3e 6423 per_cpu(load_balance_mask, i) = (void *)ptr;
df7c8e84
RR
6424 ptr += cpumask_size();
6425 }
6426#endif /* CONFIG_CPUMASK_OFFSTACK */
434d53b0 6427 }
dd41f596 6428
57d885fe
GH
6429#ifdef CONFIG_SMP
6430 init_defrootdomain();
6431#endif
6432
d0b27fa7
PZ
6433 init_rt_bandwidth(&def_rt_bandwidth,
6434 global_rt_period(), global_rt_runtime());
6435
6436#ifdef CONFIG_RT_GROUP_SCHED
07e06b01 6437 init_rt_bandwidth(&root_task_group.rt_bandwidth,
d0b27fa7 6438 global_rt_period(), global_rt_runtime());
6d6bc0ad 6439#endif /* CONFIG_RT_GROUP_SCHED */
d0b27fa7 6440
7c941438 6441#ifdef CONFIG_CGROUP_SCHED
07e06b01
YZ
6442 list_add(&root_task_group.list, &task_groups);
6443 INIT_LIST_HEAD(&root_task_group.children);
f4d6f6c2 6444 INIT_LIST_HEAD(&root_task_group.siblings);
5091faa4 6445 autogroup_init(&init_task);
54c707e9 6446
7c941438 6447#endif /* CONFIG_CGROUP_SCHED */
6f505b16 6448
0a945022 6449 for_each_possible_cpu(i) {
70b97a7f 6450 struct rq *rq;
1da177e4
LT
6451
6452 rq = cpu_rq(i);
05fa785c 6453 raw_spin_lock_init(&rq->lock);
7897986b 6454 rq->nr_running = 0;
dce48a84
TG
6455 rq->calc_load_active = 0;
6456 rq->calc_load_update = jiffies + LOAD_FREQ;
acb5a9ba 6457 init_cfs_rq(&rq->cfs);
6f505b16 6458 init_rt_rq(&rq->rt, rq);
dd41f596 6459#ifdef CONFIG_FAIR_GROUP_SCHED
029632fb 6460 root_task_group.shares = ROOT_TASK_GROUP_LOAD;
6f505b16 6461 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
354d60c2 6462 /*
07e06b01 6463 * How much cpu bandwidth does root_task_group get?
354d60c2
DG
6464 *
6465 * In case of task-groups formed thr' the cgroup filesystem, it
6466 * gets 100% of the cpu resources in the system. This overall
6467 * system cpu resource is divided among the tasks of
07e06b01 6468 * root_task_group and its child task-groups in a fair manner,
354d60c2
DG
6469 * based on each entity's (task or task-group's) weight
6470 * (se->load.weight).
6471 *
07e06b01 6472 * In other words, if root_task_group has 10 tasks of weight
354d60c2
DG
6473 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6474 * then A0's share of the cpu resource is:
6475 *
0d905bca 6476 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
354d60c2 6477 *
07e06b01
YZ
6478 * We achieve this by letting root_task_group's tasks sit
6479 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
354d60c2 6480 */
ab84d31e 6481 init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
07e06b01 6482 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
354d60c2
DG
6483#endif /* CONFIG_FAIR_GROUP_SCHED */
6484
6485 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
052f1dc7 6486#ifdef CONFIG_RT_GROUP_SCHED
6f505b16 6487 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
07e06b01 6488 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
dd41f596 6489#endif
1da177e4 6490
dd41f596
IM
6491 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
6492 rq->cpu_load[j] = 0;
fdf3e95d
VP
6493
6494 rq->last_load_update_tick = jiffies;
6495
1da177e4 6496#ifdef CONFIG_SMP
41c7ce9a 6497 rq->sd = NULL;
57d885fe 6498 rq->rd = NULL;
1399fa78 6499 rq->cpu_power = SCHED_POWER_SCALE;
3f029d3c 6500 rq->post_schedule = 0;
1da177e4 6501 rq->active_balance = 0;
dd41f596 6502 rq->next_balance = jiffies;
1da177e4 6503 rq->push_cpu = 0;
0a2966b4 6504 rq->cpu = i;
1f11eb6a 6505 rq->online = 0;
eae0c9df
MG
6506 rq->idle_stamp = 0;
6507 rq->avg_idle = 2*sysctl_sched_migration_cost;
367456c7
PZ
6508
6509 INIT_LIST_HEAD(&rq->cfs_tasks);
6510
dc938520 6511 rq_attach_root(rq, &def_root_domain);
3451d024 6512#ifdef CONFIG_NO_HZ_COMMON
1c792db7 6513 rq->nohz_flags = 0;
83cd4fe2 6514#endif
265f22a9
FW
6515#ifdef CONFIG_NO_HZ_FULL
6516 rq->last_sched_tick = 0;
6517#endif
1da177e4 6518#endif
8f4d37ec 6519 init_rq_hrtick(rq);
1da177e4 6520 atomic_set(&rq->nr_iowait, 0);
1da177e4
LT
6521 }
6522
2dd73a4f 6523 set_load_weight(&init_task);
b50f60ce 6524
e107be36
AK
6525#ifdef CONFIG_PREEMPT_NOTIFIERS
6526 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
6527#endif
6528
b50f60ce 6529#ifdef CONFIG_RT_MUTEXES
732375c6 6530 plist_head_init(&init_task.pi_waiters);
b50f60ce
HC
6531#endif
6532
1da177e4
LT
6533 /*
6534 * The boot idle thread does lazy MMU switching as well:
6535 */
6536 atomic_inc(&init_mm.mm_count);
6537 enter_lazy_tlb(&init_mm, current);
6538
6539 /*
6540 * Make us the idle thread. Technically, schedule() should not be
6541 * called from this thread, however somewhere below it might be,
6542 * but because we are the idle thread, we just pick up running again
6543 * when this runqueue becomes "idle".
6544 */
6545 init_idle(current, smp_processor_id());
dce48a84
TG
6546
6547 calc_load_update = jiffies + LOAD_FREQ;
6548
dd41f596
IM
6549 /*
6550 * During early bootup we pretend to be a normal task:
6551 */
6552 current->sched_class = &fair_sched_class;
6892b75e 6553
bf4d83f6 6554#ifdef CONFIG_SMP
4cb98839 6555 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
bdddd296
RR
6556 /* May be allocated at isolcpus cmdline parse time */
6557 if (cpu_isolated_map == NULL)
6558 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
29d5e047 6559 idle_thread_set_boot_cpu();
029632fb
PZ
6560#endif
6561 init_sched_fair_class();
6a7b3dc3 6562
6892b75e 6563 scheduler_running = 1;
1da177e4
LT
6564}
6565
d902db1e 6566#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
e4aafea2
FW
6567static inline int preempt_count_equals(int preempt_offset)
6568{
234da7bc 6569 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
e4aafea2 6570
4ba8216c 6571 return (nested == preempt_offset);
e4aafea2
FW
6572}
6573
d894837f 6574void __might_sleep(const char *file, int line, int preempt_offset)
1da177e4 6575{
1da177e4
LT
6576 static unsigned long prev_jiffy; /* ratelimiting */
6577
b3fbab05 6578 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
e4aafea2
FW
6579 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
6580 system_state != SYSTEM_RUNNING || oops_in_progress)
aef745fc
IM
6581 return;
6582 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
6583 return;
6584 prev_jiffy = jiffies;
6585
3df0fc5b
PZ
6586 printk(KERN_ERR
6587 "BUG: sleeping function called from invalid context at %s:%d\n",
6588 file, line);
6589 printk(KERN_ERR
6590 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
6591 in_atomic(), irqs_disabled(),
6592 current->pid, current->comm);
aef745fc
IM
6593
6594 debug_show_held_locks(current);
6595 if (irqs_disabled())
6596 print_irqtrace_events(current);
6597 dump_stack();
1da177e4
LT
6598}
6599EXPORT_SYMBOL(__might_sleep);
6600#endif
6601
6602#ifdef CONFIG_MAGIC_SYSRQ
3a5e4dc1
AK
6603static void normalize_task(struct rq *rq, struct task_struct *p)
6604{
da7a735e
PZ
6605 const struct sched_class *prev_class = p->sched_class;
6606 int old_prio = p->prio;
3a5e4dc1 6607 int on_rq;
3e51f33f 6608
fd2f4419 6609 on_rq = p->on_rq;
3a5e4dc1 6610 if (on_rq)
4ca9b72b 6611 dequeue_task(rq, p, 0);
3a5e4dc1
AK
6612 __setscheduler(rq, p, SCHED_NORMAL, 0);
6613 if (on_rq) {
4ca9b72b 6614 enqueue_task(rq, p, 0);
3a5e4dc1
AK
6615 resched_task(rq->curr);
6616 }
da7a735e
PZ
6617
6618 check_class_changed(rq, p, prev_class, old_prio);
3a5e4dc1
AK
6619}
6620
1da177e4
LT
6621void normalize_rt_tasks(void)
6622{
a0f98a1c 6623 struct task_struct *g, *p;
1da177e4 6624 unsigned long flags;
70b97a7f 6625 struct rq *rq;
1da177e4 6626
4cf5d77a 6627 read_lock_irqsave(&tasklist_lock, flags);
a0f98a1c 6628 do_each_thread(g, p) {
178be793
IM
6629 /*
6630 * Only normalize user tasks:
6631 */
6632 if (!p->mm)
6633 continue;
6634
6cfb0d5d 6635 p->se.exec_start = 0;
6cfb0d5d 6636#ifdef CONFIG_SCHEDSTATS
41acab88
LDM
6637 p->se.statistics.wait_start = 0;
6638 p->se.statistics.sleep_start = 0;
6639 p->se.statistics.block_start = 0;
6cfb0d5d 6640#endif
dd41f596
IM
6641
6642 if (!rt_task(p)) {
6643 /*
6644 * Renice negative nice level userspace
6645 * tasks back to 0:
6646 */
6647 if (TASK_NICE(p) < 0 && p->mm)
6648 set_user_nice(p, 0);
1da177e4 6649 continue;
dd41f596 6650 }
1da177e4 6651
1d615482 6652 raw_spin_lock(&p->pi_lock);
b29739f9 6653 rq = __task_rq_lock(p);
1da177e4 6654
178be793 6655 normalize_task(rq, p);
3a5e4dc1 6656
b29739f9 6657 __task_rq_unlock(rq);
1d615482 6658 raw_spin_unlock(&p->pi_lock);
a0f98a1c
IM
6659 } while_each_thread(g, p);
6660
4cf5d77a 6661 read_unlock_irqrestore(&tasklist_lock, flags);
1da177e4
LT
6662}
6663
6664#endif /* CONFIG_MAGIC_SYSRQ */
1df5c10a 6665
67fc4e0c 6666#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
1df5c10a 6667/*
67fc4e0c 6668 * These functions are only useful for the IA64 MCA handling, or kdb.
1df5c10a
LT
6669 *
6670 * They can only be called when the whole system has been
6671 * stopped - every CPU needs to be quiescent, and no scheduling
6672 * activity can take place. Using them for anything else would
6673 * be a serious bug, and as a result, they aren't even visible
6674 * under any other configuration.
6675 */
6676
6677/**
6678 * curr_task - return the current task for a given cpu.
6679 * @cpu: the processor in question.
6680 *
6681 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
e69f6186
YB
6682 *
6683 * Return: The current task for @cpu.
1df5c10a 6684 */
36c8b586 6685struct task_struct *curr_task(int cpu)
1df5c10a
LT
6686{
6687 return cpu_curr(cpu);
6688}
6689
67fc4e0c
JW
6690#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
6691
6692#ifdef CONFIG_IA64
1df5c10a
LT
6693/**
6694 * set_curr_task - set the current task for a given cpu.
6695 * @cpu: the processor in question.
6696 * @p: the task pointer to set.
6697 *
6698 * Description: This function must only be used when non-maskable interrupts
41a2d6cf
IM
6699 * are serviced on a separate stack. It allows the architecture to switch the
6700 * notion of the current task on a cpu in a non-blocking manner. This function
1df5c10a
LT
6701 * must be called with all CPU's synchronized, and interrupts disabled, the
6702 * and caller must save the original value of the current task (see
6703 * curr_task() above) and restore that value before reenabling interrupts and
6704 * re-starting the system.
6705 *
6706 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6707 */
36c8b586 6708void set_curr_task(int cpu, struct task_struct *p)
1df5c10a
LT
6709{
6710 cpu_curr(cpu) = p;
6711}
6712
6713#endif
29f59db3 6714
7c941438 6715#ifdef CONFIG_CGROUP_SCHED
029632fb
PZ
6716/* task_group_lock serializes the addition/removal of task groups */
6717static DEFINE_SPINLOCK(task_group_lock);
6718
bccbe08a
PZ
6719static void free_sched_group(struct task_group *tg)
6720{
6721 free_fair_sched_group(tg);
6722 free_rt_sched_group(tg);
e9aa1dd1 6723 autogroup_free(tg);
bccbe08a
PZ
6724 kfree(tg);
6725}
6726
6727/* allocate runqueue etc for a new task group */
ec7dc8ac 6728struct task_group *sched_create_group(struct task_group *parent)
bccbe08a
PZ
6729{
6730 struct task_group *tg;
bccbe08a
PZ
6731
6732 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
6733 if (!tg)
6734 return ERR_PTR(-ENOMEM);
6735
ec7dc8ac 6736 if (!alloc_fair_sched_group(tg, parent))
bccbe08a
PZ
6737 goto err;
6738
ec7dc8ac 6739 if (!alloc_rt_sched_group(tg, parent))
bccbe08a
PZ
6740 goto err;
6741
ace783b9
LZ
6742 return tg;
6743
6744err:
6745 free_sched_group(tg);
6746 return ERR_PTR(-ENOMEM);
6747}
6748
6749void sched_online_group(struct task_group *tg, struct task_group *parent)
6750{
6751 unsigned long flags;
6752
8ed36996 6753 spin_lock_irqsave(&task_group_lock, flags);
6f505b16 6754 list_add_rcu(&tg->list, &task_groups);
f473aa5e
PZ
6755
6756 WARN_ON(!parent); /* root should already exist */
6757
6758 tg->parent = parent;
f473aa5e 6759 INIT_LIST_HEAD(&tg->children);
09f2724a 6760 list_add_rcu(&tg->siblings, &parent->children);
8ed36996 6761 spin_unlock_irqrestore(&task_group_lock, flags);
29f59db3
SV
6762}
6763
9b5b7751 6764/* rcu callback to free various structures associated with a task group */
6f505b16 6765static void free_sched_group_rcu(struct rcu_head *rhp)
29f59db3 6766{
29f59db3 6767 /* now it should be safe to free those cfs_rqs */
6f505b16 6768 free_sched_group(container_of(rhp, struct task_group, rcu));
29f59db3
SV
6769}
6770
9b5b7751 6771/* Destroy runqueue etc associated with a task group */
4cf86d77 6772void sched_destroy_group(struct task_group *tg)
ace783b9
LZ
6773{
6774 /* wait for possible concurrent references to cfs_rqs complete */
6775 call_rcu(&tg->rcu, free_sched_group_rcu);
6776}
6777
6778void sched_offline_group(struct task_group *tg)
29f59db3 6779{
8ed36996 6780 unsigned long flags;
9b5b7751 6781 int i;
29f59db3 6782
3d4b47b4
PZ
6783 /* end participation in shares distribution */
6784 for_each_possible_cpu(i)
bccbe08a 6785 unregister_fair_sched_group(tg, i);
3d4b47b4
PZ
6786
6787 spin_lock_irqsave(&task_group_lock, flags);
6f505b16 6788 list_del_rcu(&tg->list);
f473aa5e 6789 list_del_rcu(&tg->siblings);
8ed36996 6790 spin_unlock_irqrestore(&task_group_lock, flags);
29f59db3
SV
6791}
6792
9b5b7751 6793/* change task's runqueue when it moves between groups.
3a252015
IM
6794 * The caller of this function should have put the task in its new group
6795 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
6796 * reflect its new group.
9b5b7751
SV
6797 */
6798void sched_move_task(struct task_struct *tsk)
29f59db3 6799{
8323f26c 6800 struct task_group *tg;
29f59db3
SV
6801 int on_rq, running;
6802 unsigned long flags;
6803 struct rq *rq;
6804
6805 rq = task_rq_lock(tsk, &flags);
6806
051a1d1a 6807 running = task_current(rq, tsk);
fd2f4419 6808 on_rq = tsk->on_rq;
29f59db3 6809
0e1f3483 6810 if (on_rq)
29f59db3 6811 dequeue_task(rq, tsk, 0);
0e1f3483
HS
6812 if (unlikely(running))
6813 tsk->sched_class->put_prev_task(rq, tsk);
29f59db3 6814
8af01f56 6815 tg = container_of(task_css_check(tsk, cpu_cgroup_subsys_id,
8323f26c
PZ
6816 lockdep_is_held(&tsk->sighand->siglock)),
6817 struct task_group, css);
6818 tg = autogroup_task_group(tsk, tg);
6819 tsk->sched_task_group = tg;
6820
810b3817 6821#ifdef CONFIG_FAIR_GROUP_SCHED
b2b5ce02
PZ
6822 if (tsk->sched_class->task_move_group)
6823 tsk->sched_class->task_move_group(tsk, on_rq);
6824 else
810b3817 6825#endif
b2b5ce02 6826 set_task_rq(tsk, task_cpu(tsk));
810b3817 6827
0e1f3483
HS
6828 if (unlikely(running))
6829 tsk->sched_class->set_curr_task(rq);
6830 if (on_rq)
371fd7e7 6831 enqueue_task(rq, tsk, 0);
29f59db3 6832
0122ec5b 6833 task_rq_unlock(rq, tsk, &flags);
29f59db3 6834}
7c941438 6835#endif /* CONFIG_CGROUP_SCHED */
29f59db3 6836
a790de99 6837#if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
9f0c1e56
PZ
6838static unsigned long to_ratio(u64 period, u64 runtime)
6839{
6840 if (runtime == RUNTIME_INF)
9a7e0b18 6841 return 1ULL << 20;
9f0c1e56 6842
9a7e0b18 6843 return div64_u64(runtime << 20, period);
9f0c1e56 6844}
a790de99
PT
6845#endif
6846
6847#ifdef CONFIG_RT_GROUP_SCHED
6848/*
6849 * Ensure that the real time constraints are schedulable.
6850 */
6851static DEFINE_MUTEX(rt_constraints_mutex);
9f0c1e56 6852
9a7e0b18
PZ
6853/* Must be called with tasklist_lock held */
6854static inline int tg_has_rt_tasks(struct task_group *tg)
b40b2e8e 6855{
9a7e0b18 6856 struct task_struct *g, *p;
b40b2e8e 6857
9a7e0b18 6858 do_each_thread(g, p) {
029632fb 6859 if (rt_task(p) && task_rq(p)->rt.tg == tg)
9a7e0b18
PZ
6860 return 1;
6861 } while_each_thread(g, p);
b40b2e8e 6862
9a7e0b18
PZ
6863 return 0;
6864}
b40b2e8e 6865
9a7e0b18
PZ
6866struct rt_schedulable_data {
6867 struct task_group *tg;
6868 u64 rt_period;
6869 u64 rt_runtime;
6870};
b40b2e8e 6871
a790de99 6872static int tg_rt_schedulable(struct task_group *tg, void *data)
9a7e0b18
PZ
6873{
6874 struct rt_schedulable_data *d = data;
6875 struct task_group *child;
6876 unsigned long total, sum = 0;
6877 u64 period, runtime;
b40b2e8e 6878
9a7e0b18
PZ
6879 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
6880 runtime = tg->rt_bandwidth.rt_runtime;
b40b2e8e 6881
9a7e0b18
PZ
6882 if (tg == d->tg) {
6883 period = d->rt_period;
6884 runtime = d->rt_runtime;
b40b2e8e 6885 }
b40b2e8e 6886
4653f803
PZ
6887 /*
6888 * Cannot have more runtime than the period.
6889 */
6890 if (runtime > period && runtime != RUNTIME_INF)
6891 return -EINVAL;
6f505b16 6892
4653f803
PZ
6893 /*
6894 * Ensure we don't starve existing RT tasks.
6895 */
9a7e0b18
PZ
6896 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
6897 return -EBUSY;
6f505b16 6898
9a7e0b18 6899 total = to_ratio(period, runtime);
6f505b16 6900
4653f803
PZ
6901 /*
6902 * Nobody can have more than the global setting allows.
6903 */
6904 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
6905 return -EINVAL;
6f505b16 6906
4653f803
PZ
6907 /*
6908 * The sum of our children's runtime should not exceed our own.
6909 */
9a7e0b18
PZ
6910 list_for_each_entry_rcu(child, &tg->children, siblings) {
6911 period = ktime_to_ns(child->rt_bandwidth.rt_period);
6912 runtime = child->rt_bandwidth.rt_runtime;
6f505b16 6913
9a7e0b18
PZ
6914 if (child == d->tg) {
6915 period = d->rt_period;
6916 runtime = d->rt_runtime;
6917 }
6f505b16 6918
9a7e0b18 6919 sum += to_ratio(period, runtime);
9f0c1e56 6920 }
6f505b16 6921
9a7e0b18
PZ
6922 if (sum > total)
6923 return -EINVAL;
6924
6925 return 0;
6f505b16
PZ
6926}
6927
9a7e0b18 6928static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
521f1a24 6929{
8277434e
PT
6930 int ret;
6931
9a7e0b18
PZ
6932 struct rt_schedulable_data data = {
6933 .tg = tg,
6934 .rt_period = period,
6935 .rt_runtime = runtime,
6936 };
6937
8277434e
PT
6938 rcu_read_lock();
6939 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
6940 rcu_read_unlock();
6941
6942 return ret;
521f1a24
DG
6943}
6944
ab84d31e 6945static int tg_set_rt_bandwidth(struct task_group *tg,
d0b27fa7 6946 u64 rt_period, u64 rt_runtime)
6f505b16 6947{
ac086bc2 6948 int i, err = 0;
9f0c1e56 6949
9f0c1e56 6950 mutex_lock(&rt_constraints_mutex);
521f1a24 6951 read_lock(&tasklist_lock);
9a7e0b18
PZ
6952 err = __rt_schedulable(tg, rt_period, rt_runtime);
6953 if (err)
9f0c1e56 6954 goto unlock;
ac086bc2 6955
0986b11b 6956 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
d0b27fa7
PZ
6957 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
6958 tg->rt_bandwidth.rt_runtime = rt_runtime;
ac086bc2
PZ
6959
6960 for_each_possible_cpu(i) {
6961 struct rt_rq *rt_rq = tg->rt_rq[i];
6962
0986b11b 6963 raw_spin_lock(&rt_rq->rt_runtime_lock);
ac086bc2 6964 rt_rq->rt_runtime = rt_runtime;
0986b11b 6965 raw_spin_unlock(&rt_rq->rt_runtime_lock);
ac086bc2 6966 }
0986b11b 6967 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
49246274 6968unlock:
521f1a24 6969 read_unlock(&tasklist_lock);
9f0c1e56
PZ
6970 mutex_unlock(&rt_constraints_mutex);
6971
6972 return err;
6f505b16
PZ
6973}
6974
25cc7da7 6975static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
d0b27fa7
PZ
6976{
6977 u64 rt_runtime, rt_period;
6978
6979 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
6980 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
6981 if (rt_runtime_us < 0)
6982 rt_runtime = RUNTIME_INF;
6983
ab84d31e 6984 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
d0b27fa7
PZ
6985}
6986
25cc7da7 6987static long sched_group_rt_runtime(struct task_group *tg)
9f0c1e56
PZ
6988{
6989 u64 rt_runtime_us;
6990
d0b27fa7 6991 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
9f0c1e56
PZ
6992 return -1;
6993
d0b27fa7 6994 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
9f0c1e56
PZ
6995 do_div(rt_runtime_us, NSEC_PER_USEC);
6996 return rt_runtime_us;
6997}
d0b27fa7 6998
25cc7da7 6999static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
d0b27fa7
PZ
7000{
7001 u64 rt_runtime, rt_period;
7002
7003 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
7004 rt_runtime = tg->rt_bandwidth.rt_runtime;
7005
619b0488
R
7006 if (rt_period == 0)
7007 return -EINVAL;
7008
ab84d31e 7009 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
d0b27fa7
PZ
7010}
7011
25cc7da7 7012static long sched_group_rt_period(struct task_group *tg)
d0b27fa7
PZ
7013{
7014 u64 rt_period_us;
7015
7016 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
7017 do_div(rt_period_us, NSEC_PER_USEC);
7018 return rt_period_us;
7019}
7020
7021static int sched_rt_global_constraints(void)
7022{
4653f803 7023 u64 runtime, period;
d0b27fa7
PZ
7024 int ret = 0;
7025
ec5d4989
HS
7026 if (sysctl_sched_rt_period <= 0)
7027 return -EINVAL;
7028
4653f803
PZ
7029 runtime = global_rt_runtime();
7030 period = global_rt_period();
7031
7032 /*
7033 * Sanity check on the sysctl variables.
7034 */
7035 if (runtime > period && runtime != RUNTIME_INF)
7036 return -EINVAL;
10b612f4 7037
d0b27fa7 7038 mutex_lock(&rt_constraints_mutex);
9a7e0b18 7039 read_lock(&tasklist_lock);
4653f803 7040 ret = __rt_schedulable(NULL, 0, 0);
9a7e0b18 7041 read_unlock(&tasklist_lock);
d0b27fa7
PZ
7042 mutex_unlock(&rt_constraints_mutex);
7043
7044 return ret;
7045}
54e99124 7046
25cc7da7 7047static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
54e99124
DG
7048{
7049 /* Don't accept realtime tasks when there is no way for them to run */
7050 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
7051 return 0;
7052
7053 return 1;
7054}
7055
6d6bc0ad 7056#else /* !CONFIG_RT_GROUP_SCHED */
d0b27fa7
PZ
7057static int sched_rt_global_constraints(void)
7058{
ac086bc2
PZ
7059 unsigned long flags;
7060 int i;
7061
ec5d4989
HS
7062 if (sysctl_sched_rt_period <= 0)
7063 return -EINVAL;
7064
60aa605d
PZ
7065 /*
7066 * There's always some RT tasks in the root group
7067 * -- migration, kstopmachine etc..
7068 */
7069 if (sysctl_sched_rt_runtime == 0)
7070 return -EBUSY;
7071
0986b11b 7072 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
ac086bc2
PZ
7073 for_each_possible_cpu(i) {
7074 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
7075
0986b11b 7076 raw_spin_lock(&rt_rq->rt_runtime_lock);
ac086bc2 7077 rt_rq->rt_runtime = global_rt_runtime();
0986b11b 7078 raw_spin_unlock(&rt_rq->rt_runtime_lock);
ac086bc2 7079 }
0986b11b 7080 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
ac086bc2 7081
d0b27fa7
PZ
7082 return 0;
7083}
6d6bc0ad 7084#endif /* CONFIG_RT_GROUP_SCHED */
d0b27fa7 7085
ce0dbbbb
CW
7086int sched_rr_handler(struct ctl_table *table, int write,
7087 void __user *buffer, size_t *lenp,
7088 loff_t *ppos)
7089{
7090 int ret;
7091 static DEFINE_MUTEX(mutex);
7092
7093 mutex_lock(&mutex);
7094 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7095 /* make sure that internally we keep jiffies */
7096 /* also, writing zero resets timeslice to default */
7097 if (!ret && write) {
7098 sched_rr_timeslice = sched_rr_timeslice <= 0 ?
7099 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice);
7100 }
7101 mutex_unlock(&mutex);
7102 return ret;
7103}
7104
d0b27fa7 7105int sched_rt_handler(struct ctl_table *table, int write,
8d65af78 7106 void __user *buffer, size_t *lenp,
d0b27fa7
PZ
7107 loff_t *ppos)
7108{
7109 int ret;
7110 int old_period, old_runtime;
7111 static DEFINE_MUTEX(mutex);
7112
7113 mutex_lock(&mutex);
7114 old_period = sysctl_sched_rt_period;
7115 old_runtime = sysctl_sched_rt_runtime;
7116
8d65af78 7117 ret = proc_dointvec(table, write, buffer, lenp, ppos);
d0b27fa7
PZ
7118
7119 if (!ret && write) {
7120 ret = sched_rt_global_constraints();
7121 if (ret) {
7122 sysctl_sched_rt_period = old_period;
7123 sysctl_sched_rt_runtime = old_runtime;
7124 } else {
7125 def_rt_bandwidth.rt_runtime = global_rt_runtime();
7126 def_rt_bandwidth.rt_period =
7127 ns_to_ktime(global_rt_period());
7128 }
7129 }
7130 mutex_unlock(&mutex);
7131
7132 return ret;
7133}
68318b8e 7134
052f1dc7 7135#ifdef CONFIG_CGROUP_SCHED
68318b8e 7136
a7c6d554 7137static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
68318b8e 7138{
a7c6d554 7139 return css ? container_of(css, struct task_group, css) : NULL;
68318b8e
SV
7140}
7141
eb95419b
TH
7142static struct cgroup_subsys_state *
7143cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
68318b8e 7144{
eb95419b
TH
7145 struct task_group *parent = css_tg(parent_css);
7146 struct task_group *tg;
68318b8e 7147
eb95419b 7148 if (!parent) {
68318b8e 7149 /* This is early initialization for the top cgroup */
07e06b01 7150 return &root_task_group.css;
68318b8e
SV
7151 }
7152
ec7dc8ac 7153 tg = sched_create_group(parent);
68318b8e
SV
7154 if (IS_ERR(tg))
7155 return ERR_PTR(-ENOMEM);
7156
68318b8e
SV
7157 return &tg->css;
7158}
7159
eb95419b 7160static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
ace783b9 7161{
eb95419b
TH
7162 struct task_group *tg = css_tg(css);
7163 struct task_group *parent = css_tg(css_parent(css));
ace783b9 7164
63876986
TH
7165 if (parent)
7166 sched_online_group(tg, parent);
ace783b9
LZ
7167 return 0;
7168}
7169
eb95419b 7170static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
68318b8e 7171{
eb95419b 7172 struct task_group *tg = css_tg(css);
68318b8e
SV
7173
7174 sched_destroy_group(tg);
7175}
7176
eb95419b 7177static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css)
ace783b9 7178{
eb95419b 7179 struct task_group *tg = css_tg(css);
ace783b9
LZ
7180
7181 sched_offline_group(tg);
7182}
7183
eb95419b 7184static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css,
bb9d97b6 7185 struct cgroup_taskset *tset)
68318b8e 7186{
bb9d97b6
TH
7187 struct task_struct *task;
7188
d99c8727 7189 cgroup_taskset_for_each(task, css, tset) {
b68aa230 7190#ifdef CONFIG_RT_GROUP_SCHED
eb95419b 7191 if (!sched_rt_can_attach(css_tg(css), task))
bb9d97b6 7192 return -EINVAL;
b68aa230 7193#else
bb9d97b6
TH
7194 /* We don't support RT-tasks being in separate groups */
7195 if (task->sched_class != &fair_sched_class)
7196 return -EINVAL;
b68aa230 7197#endif
bb9d97b6 7198 }
be367d09
BB
7199 return 0;
7200}
68318b8e 7201
eb95419b 7202static void cpu_cgroup_attach(struct cgroup_subsys_state *css,
bb9d97b6 7203 struct cgroup_taskset *tset)
68318b8e 7204{
bb9d97b6
TH
7205 struct task_struct *task;
7206
d99c8727 7207 cgroup_taskset_for_each(task, css, tset)
bb9d97b6 7208 sched_move_task(task);
68318b8e
SV
7209}
7210
eb95419b
TH
7211static void cpu_cgroup_exit(struct cgroup_subsys_state *css,
7212 struct cgroup_subsys_state *old_css,
7213 struct task_struct *task)
068c5cc5
PZ
7214{
7215 /*
7216 * cgroup_exit() is called in the copy_process() failure path.
7217 * Ignore this case since the task hasn't ran yet, this avoids
7218 * trying to poke a half freed task state from generic code.
7219 */
7220 if (!(task->flags & PF_EXITING))
7221 return;
7222
7223 sched_move_task(task);
7224}
7225
052f1dc7 7226#ifdef CONFIG_FAIR_GROUP_SCHED
182446d0
TH
7227static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
7228 struct cftype *cftype, u64 shareval)
68318b8e 7229{
182446d0 7230 return sched_group_set_shares(css_tg(css), scale_load(shareval));
68318b8e
SV
7231}
7232
182446d0
TH
7233static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
7234 struct cftype *cft)
68318b8e 7235{
182446d0 7236 struct task_group *tg = css_tg(css);
68318b8e 7237
c8b28116 7238 return (u64) scale_load_down(tg->shares);
68318b8e 7239}
ab84d31e
PT
7240
7241#ifdef CONFIG_CFS_BANDWIDTH
a790de99
PT
7242static DEFINE_MUTEX(cfs_constraints_mutex);
7243
ab84d31e
PT
7244const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
7245const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
7246
a790de99
PT
7247static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
7248
ab84d31e
PT
7249static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
7250{
56f570e5 7251 int i, ret = 0, runtime_enabled, runtime_was_enabled;
029632fb 7252 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
ab84d31e
PT
7253
7254 if (tg == &root_task_group)
7255 return -EINVAL;
7256
7257 /*
7258 * Ensure we have at some amount of bandwidth every period. This is
7259 * to prevent reaching a state of large arrears when throttled via
7260 * entity_tick() resulting in prolonged exit starvation.
7261 */
7262 if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
7263 return -EINVAL;
7264
7265 /*
7266 * Likewise, bound things on the otherside by preventing insane quota
7267 * periods. This also allows us to normalize in computing quota
7268 * feasibility.
7269 */
7270 if (period > max_cfs_quota_period)
7271 return -EINVAL;
7272
a790de99
PT
7273 mutex_lock(&cfs_constraints_mutex);
7274 ret = __cfs_schedulable(tg, period, quota);
7275 if (ret)
7276 goto out_unlock;
7277
58088ad0 7278 runtime_enabled = quota != RUNTIME_INF;
56f570e5
PT
7279 runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
7280 account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled);
ab84d31e
PT
7281 raw_spin_lock_irq(&cfs_b->lock);
7282 cfs_b->period = ns_to_ktime(period);
7283 cfs_b->quota = quota;
58088ad0 7284
a9cf55b2 7285 __refill_cfs_bandwidth_runtime(cfs_b);
58088ad0
PT
7286 /* restart the period timer (if active) to handle new period expiry */
7287 if (runtime_enabled && cfs_b->timer_active) {
7288 /* force a reprogram */
7289 cfs_b->timer_active = 0;
7290 __start_cfs_bandwidth(cfs_b);
7291 }
ab84d31e
PT
7292 raw_spin_unlock_irq(&cfs_b->lock);
7293
7294 for_each_possible_cpu(i) {
7295 struct cfs_rq *cfs_rq = tg->cfs_rq[i];
029632fb 7296 struct rq *rq = cfs_rq->rq;
ab84d31e
PT
7297
7298 raw_spin_lock_irq(&rq->lock);
58088ad0 7299 cfs_rq->runtime_enabled = runtime_enabled;
ab84d31e 7300 cfs_rq->runtime_remaining = 0;
671fd9da 7301
029632fb 7302 if (cfs_rq->throttled)
671fd9da 7303 unthrottle_cfs_rq(cfs_rq);
ab84d31e
PT
7304 raw_spin_unlock_irq(&rq->lock);
7305 }
a790de99
PT
7306out_unlock:
7307 mutex_unlock(&cfs_constraints_mutex);
ab84d31e 7308
a790de99 7309 return ret;
ab84d31e
PT
7310}
7311
7312int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
7313{
7314 u64 quota, period;
7315
029632fb 7316 period = ktime_to_ns(tg->cfs_bandwidth.period);
ab84d31e
PT
7317 if (cfs_quota_us < 0)
7318 quota = RUNTIME_INF;
7319 else
7320 quota = (u64)cfs_quota_us * NSEC_PER_USEC;
7321
7322 return tg_set_cfs_bandwidth(tg, period, quota);
7323}
7324
7325long tg_get_cfs_quota(struct task_group *tg)
7326{
7327 u64 quota_us;
7328
029632fb 7329 if (tg->cfs_bandwidth.quota == RUNTIME_INF)
ab84d31e
PT
7330 return -1;
7331
029632fb 7332 quota_us = tg->cfs_bandwidth.quota;
ab84d31e
PT
7333 do_div(quota_us, NSEC_PER_USEC);
7334
7335 return quota_us;
7336}
7337
7338int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
7339{
7340 u64 quota, period;
7341
7342 period = (u64)cfs_period_us * NSEC_PER_USEC;
029632fb 7343 quota = tg->cfs_bandwidth.quota;
ab84d31e 7344
ab84d31e
PT
7345 return tg_set_cfs_bandwidth(tg, period, quota);
7346}
7347
7348long tg_get_cfs_period(struct task_group *tg)
7349{
7350 u64 cfs_period_us;
7351
029632fb 7352 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
ab84d31e
PT
7353 do_div(cfs_period_us, NSEC_PER_USEC);
7354
7355 return cfs_period_us;
7356}
7357
182446d0
TH
7358static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css,
7359 struct cftype *cft)
ab84d31e 7360{
182446d0 7361 return tg_get_cfs_quota(css_tg(css));
ab84d31e
PT
7362}
7363
182446d0
TH
7364static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css,
7365 struct cftype *cftype, s64 cfs_quota_us)
ab84d31e 7366{
182446d0 7367 return tg_set_cfs_quota(css_tg(css), cfs_quota_us);
ab84d31e
PT
7368}
7369
182446d0
TH
7370static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css,
7371 struct cftype *cft)
ab84d31e 7372{
182446d0 7373 return tg_get_cfs_period(css_tg(css));
ab84d31e
PT
7374}
7375
182446d0
TH
7376static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css,
7377 struct cftype *cftype, u64 cfs_period_us)
ab84d31e 7378{
182446d0 7379 return tg_set_cfs_period(css_tg(css), cfs_period_us);
ab84d31e
PT
7380}
7381
a790de99
PT
7382struct cfs_schedulable_data {
7383 struct task_group *tg;
7384 u64 period, quota;
7385};
7386
7387/*
7388 * normalize group quota/period to be quota/max_period
7389 * note: units are usecs
7390 */
7391static u64 normalize_cfs_quota(struct task_group *tg,
7392 struct cfs_schedulable_data *d)
7393{
7394 u64 quota, period;
7395
7396 if (tg == d->tg) {
7397 period = d->period;
7398 quota = d->quota;
7399 } else {
7400 period = tg_get_cfs_period(tg);
7401 quota = tg_get_cfs_quota(tg);
7402 }
7403
7404 /* note: these should typically be equivalent */
7405 if (quota == RUNTIME_INF || quota == -1)
7406 return RUNTIME_INF;
7407
7408 return to_ratio(period, quota);
7409}
7410
7411static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
7412{
7413 struct cfs_schedulable_data *d = data;
029632fb 7414 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
a790de99
PT
7415 s64 quota = 0, parent_quota = -1;
7416
7417 if (!tg->parent) {
7418 quota = RUNTIME_INF;
7419 } else {
029632fb 7420 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
a790de99
PT
7421
7422 quota = normalize_cfs_quota(tg, d);
7423 parent_quota = parent_b->hierarchal_quota;
7424
7425 /*
7426 * ensure max(child_quota) <= parent_quota, inherit when no
7427 * limit is set
7428 */
7429 if (quota == RUNTIME_INF)
7430 quota = parent_quota;
7431 else if (parent_quota != RUNTIME_INF && quota > parent_quota)
7432 return -EINVAL;
7433 }
7434 cfs_b->hierarchal_quota = quota;
7435
7436 return 0;
7437}
7438
7439static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
7440{
8277434e 7441 int ret;
a790de99
PT
7442 struct cfs_schedulable_data data = {
7443 .tg = tg,
7444 .period = period,
7445 .quota = quota,
7446 };
7447
7448 if (quota != RUNTIME_INF) {
7449 do_div(data.period, NSEC_PER_USEC);
7450 do_div(data.quota, NSEC_PER_USEC);
7451 }
7452
8277434e
PT
7453 rcu_read_lock();
7454 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
7455 rcu_read_unlock();
7456
7457 return ret;
a790de99 7458}
e8da1b18 7459
182446d0 7460static int cpu_stats_show(struct cgroup_subsys_state *css, struct cftype *cft,
e8da1b18
NR
7461 struct cgroup_map_cb *cb)
7462{
182446d0 7463 struct task_group *tg = css_tg(css);
029632fb 7464 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
e8da1b18
NR
7465
7466 cb->fill(cb, "nr_periods", cfs_b->nr_periods);
7467 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled);
7468 cb->fill(cb, "throttled_time", cfs_b->throttled_time);
7469
7470 return 0;
7471}
ab84d31e 7472#endif /* CONFIG_CFS_BANDWIDTH */
6d6bc0ad 7473#endif /* CONFIG_FAIR_GROUP_SCHED */
68318b8e 7474
052f1dc7 7475#ifdef CONFIG_RT_GROUP_SCHED
182446d0
TH
7476static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
7477 struct cftype *cft, s64 val)
6f505b16 7478{
182446d0 7479 return sched_group_set_rt_runtime(css_tg(css), val);
6f505b16
PZ
7480}
7481
182446d0
TH
7482static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css,
7483 struct cftype *cft)
6f505b16 7484{
182446d0 7485 return sched_group_rt_runtime(css_tg(css));
6f505b16 7486}
d0b27fa7 7487
182446d0
TH
7488static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css,
7489 struct cftype *cftype, u64 rt_period_us)
d0b27fa7 7490{
182446d0 7491 return sched_group_set_rt_period(css_tg(css), rt_period_us);
d0b27fa7
PZ
7492}
7493
182446d0
TH
7494static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
7495 struct cftype *cft)
d0b27fa7 7496{
182446d0 7497 return sched_group_rt_period(css_tg(css));
d0b27fa7 7498}
6d6bc0ad 7499#endif /* CONFIG_RT_GROUP_SCHED */
6f505b16 7500
fe5c7cc2 7501static struct cftype cpu_files[] = {
052f1dc7 7502#ifdef CONFIG_FAIR_GROUP_SCHED
fe5c7cc2
PM
7503 {
7504 .name = "shares",
f4c753b7
PM
7505 .read_u64 = cpu_shares_read_u64,
7506 .write_u64 = cpu_shares_write_u64,
fe5c7cc2 7507 },
052f1dc7 7508#endif
ab84d31e
PT
7509#ifdef CONFIG_CFS_BANDWIDTH
7510 {
7511 .name = "cfs_quota_us",
7512 .read_s64 = cpu_cfs_quota_read_s64,
7513 .write_s64 = cpu_cfs_quota_write_s64,
7514 },
7515 {
7516 .name = "cfs_period_us",
7517 .read_u64 = cpu_cfs_period_read_u64,
7518 .write_u64 = cpu_cfs_period_write_u64,
7519 },
e8da1b18
NR
7520 {
7521 .name = "stat",
7522 .read_map = cpu_stats_show,
7523 },
ab84d31e 7524#endif
052f1dc7 7525#ifdef CONFIG_RT_GROUP_SCHED
6f505b16 7526 {
9f0c1e56 7527 .name = "rt_runtime_us",
06ecb27c
PM
7528 .read_s64 = cpu_rt_runtime_read,
7529 .write_s64 = cpu_rt_runtime_write,
6f505b16 7530 },
d0b27fa7
PZ
7531 {
7532 .name = "rt_period_us",
f4c753b7
PM
7533 .read_u64 = cpu_rt_period_read_uint,
7534 .write_u64 = cpu_rt_period_write_uint,
d0b27fa7 7535 },
052f1dc7 7536#endif
4baf6e33 7537 { } /* terminate */
68318b8e
SV
7538};
7539
68318b8e 7540struct cgroup_subsys cpu_cgroup_subsys = {
38605cae 7541 .name = "cpu",
92fb9748
TH
7542 .css_alloc = cpu_cgroup_css_alloc,
7543 .css_free = cpu_cgroup_css_free,
ace783b9
LZ
7544 .css_online = cpu_cgroup_css_online,
7545 .css_offline = cpu_cgroup_css_offline,
bb9d97b6
TH
7546 .can_attach = cpu_cgroup_can_attach,
7547 .attach = cpu_cgroup_attach,
068c5cc5 7548 .exit = cpu_cgroup_exit,
38605cae 7549 .subsys_id = cpu_cgroup_subsys_id,
4baf6e33 7550 .base_cftypes = cpu_files,
68318b8e
SV
7551 .early_init = 1,
7552};
7553
052f1dc7 7554#endif /* CONFIG_CGROUP_SCHED */
d842de87 7555
b637a328
PM
7556void dump_cpu_task(int cpu)
7557{
7558 pr_info("Task dump for CPU %d:\n", cpu);
7559 sched_show_task(cpu_curr(cpu));
7560}