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1 | /* |
2 | * kernel/sched/core.c |
3 | * |
4 | * Kernel scheduler and related syscalls |
5 | * |
6 | * Copyright (C) 1991-2002 Linus Torvalds |
7 | * |
8 | * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and |
9 | * make semaphores SMP safe |
10 | * 1998-11-19 Implemented schedule_timeout() and related stuff |
11 | * by Andrea Arcangeli |
12 | * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: |
13 | * hybrid priority-list and round-robin design with |
14 | * an array-switch method of distributing timeslices |
15 | * and per-CPU runqueues. Cleanups and useful suggestions |
16 | * by Davide Libenzi, preemptible kernel bits by Robert Love. |
17 | * 2003-09-03 Interactivity tuning by Con Kolivas. |
18 | * 2004-04-02 Scheduler domains code by Nick Piggin |
19 | * 2007-04-15 Work begun on replacing all interactivity tuning with a |
20 | * fair scheduling design by Con Kolivas. |
21 | * 2007-05-05 Load balancing (smp-nice) and other improvements |
22 | * by Peter Williams |
23 | * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith |
24 | * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri |
25 | * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, |
26 | * Thomas Gleixner, Mike Kravetz |
27 | */ |
28 | |
29 | #include <linux/mm.h> |
30 | #include <linux/module.h> |
31 | #include <linux/nmi.h> |
32 | #include <linux/init.h> |
33 | #include <linux/uaccess.h> |
34 | #include <linux/highmem.h> |
35 | #include <asm/mmu_context.h> |
36 | #include <linux/interrupt.h> |
37 | #include <linux/capability.h> |
38 | #include <linux/completion.h> |
39 | #include <linux/kernel_stat.h> |
40 | #include <linux/debug_locks.h> |
41 | #include <linux/perf_event.h> |
42 | #include <linux/security.h> |
43 | #include <linux/notifier.h> |
44 | #include <linux/profile.h> |
45 | #include <linux/freezer.h> |
46 | #include <linux/vmalloc.h> |
47 | #include <linux/blkdev.h> |
48 | #include <linux/delay.h> |
49 | #include <linux/pid_namespace.h> |
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> |
57 | #include <linux/proc_fs.h> |
58 | #include <linux/seq_file.h> |
59 | #include <linux/sysctl.h> |
60 | #include <linux/syscalls.h> |
61 | #include <linux/times.h> |
62 | #include <linux/tsacct_kern.h> |
63 | #include <linux/kprobes.h> |
64 | #include <linux/delayacct.h> |
65 | #include <linux/unistd.h> |
66 | #include <linux/pagemap.h> |
67 | #include <linux/hrtimer.h> |
68 | #include <linux/tick.h> |
69 | #include <linux/debugfs.h> |
70 | #include <linux/ctype.h> |
71 | #include <linux/ftrace.h> |
72 | #include <linux/slab.h> |
73 | #include <linux/init_task.h> |
74 | #include <linux/binfmts.h> |
75 | |
76 | #include <asm/switch_to.h> |
77 | #include <asm/tlb.h> |
78 | #include <asm/irq_regs.h> |
79 | #include <asm/mutex.h> |
80 | #ifdef CONFIG_PARAVIRT |
81 | #include <asm/paravirt.h> |
82 | #endif |
83 | |
84 | #include "sched.h" |
85 | #include "../workqueue_sched.h" |
86 | #include "../smpboot.h" |
87 | |
88 | #define CREATE_TRACE_POINTS |
89 | #include <trace/events/sched.h> |
90 | |
91 | void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) |
92 | { |
93 | unsigned long delta; |
94 | ktime_t soft, hard, now; |
95 | |
96 | for (;;) { |
97 | if (hrtimer_active(period_timer)) |
98 | break; |
99 | |
100 | now = hrtimer_cb_get_time(period_timer); |
101 | hrtimer_forward(period_timer, now, period); |
102 | |
103 | soft = hrtimer_get_softexpires(period_timer); |
104 | hard = hrtimer_get_expires(period_timer); |
105 | delta = ktime_to_ns(ktime_sub(hard, soft)); |
106 | __hrtimer_start_range_ns(period_timer, soft, delta, |
107 | HRTIMER_MODE_ABS_PINNED, 0); |
108 | } |
109 | } |
110 | |
111 | DEFINE_MUTEX(sched_domains_mutex); |
112 | DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
113 | |
114 | static void update_rq_clock_task(struct rq *rq, s64 delta); |
115 | |
116 | void update_rq_clock(struct rq *rq) |
117 | { |
118 | s64 delta; |
119 | |
120 | if (rq->skip_clock_update > 0) |
121 | return; |
122 | |
123 | delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; |
124 | rq->clock += delta; |
125 | update_rq_clock_task(rq, delta); |
126 | } |
127 | |
128 | /* |
129 | * Debugging: various feature bits |
130 | */ |
131 | |
132 | #define SCHED_FEAT(name, enabled) \ |
133 | (1UL << __SCHED_FEAT_##name) * enabled | |
134 | |
135 | const_debug unsigned int sysctl_sched_features = |
136 | #include "features.h" |
137 | 0; |
138 | |
139 | #undef SCHED_FEAT |
140 | |
141 | #ifdef CONFIG_SCHED_DEBUG |
142 | #define SCHED_FEAT(name, enabled) \ |
143 | #name , |
144 | |
145 | static const char * const sched_feat_names[] = { |
146 | #include "features.h" |
147 | }; |
148 | |
149 | #undef SCHED_FEAT |
150 | |
151 | static int sched_feat_show(struct seq_file *m, void *v) |
152 | { |
153 | int i; |
154 | |
155 | for (i = 0; i < __SCHED_FEAT_NR; i++) { |
156 | if (!(sysctl_sched_features & (1UL << i))) |
157 | seq_puts(m, "NO_"); |
158 | seq_printf(m, "%s ", sched_feat_names[i]); |
159 | } |
160 | seq_puts(m, "\n"); |
161 | |
162 | return 0; |
163 | } |
164 | |
165 | #ifdef HAVE_JUMP_LABEL |
166 | |
167 | #define jump_label_key__true STATIC_KEY_INIT_TRUE |
168 | #define jump_label_key__false STATIC_KEY_INIT_FALSE |
169 | |
170 | #define SCHED_FEAT(name, enabled) \ |
171 | jump_label_key__##enabled , |
172 | |
173 | struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { |
174 | #include "features.h" |
175 | }; |
176 | |
177 | #undef SCHED_FEAT |
178 | |
179 | static void sched_feat_disable(int i) |
180 | { |
181 | if (static_key_enabled(&sched_feat_keys[i])) |
182 | static_key_slow_dec(&sched_feat_keys[i]); |
183 | } |
184 | |
185 | static void sched_feat_enable(int i) |
186 | { |
187 | if (!static_key_enabled(&sched_feat_keys[i])) |
188 | static_key_slow_inc(&sched_feat_keys[i]); |
189 | } |
190 | #else |
191 | static void sched_feat_disable(int i) { }; |
192 | static void sched_feat_enable(int i) { }; |
193 | #endif /* HAVE_JUMP_LABEL */ |
194 | |
195 | static ssize_t |
196 | sched_feat_write(struct file *filp, const char __user *ubuf, |
197 | size_t cnt, loff_t *ppos) |
198 | { |
199 | char buf[64]; |
200 | char *cmp; |
201 | int neg = 0; |
202 | int i; |
203 | |
204 | if (cnt > 63) |
205 | cnt = 63; |
206 | |
207 | if (copy_from_user(&buf, ubuf, cnt)) |
208 | return -EFAULT; |
209 | |
210 | buf[cnt] = 0; |
211 | cmp = strstrip(buf); |
212 | |
213 | if (strncmp(cmp, "NO_", 3) == 0) { |
214 | neg = 1; |
215 | cmp += 3; |
216 | } |
217 | |
218 | for (i = 0; i < __SCHED_FEAT_NR; i++) { |
219 | if (strcmp(cmp, sched_feat_names[i]) == 0) { |
220 | if (neg) { |
221 | sysctl_sched_features &= ~(1UL << i); |
222 | sched_feat_disable(i); |
223 | } else { |
224 | sysctl_sched_features |= (1UL << i); |
225 | sched_feat_enable(i); |
226 | } |
227 | break; |
228 | } |
229 | } |
230 | |
231 | if (i == __SCHED_FEAT_NR) |
232 | return -EINVAL; |
233 | |
234 | *ppos += cnt; |
235 | |
236 | return cnt; |
237 | } |
238 | |
239 | static int sched_feat_open(struct inode *inode, struct file *filp) |
240 | { |
241 | return single_open(filp, sched_feat_show, NULL); |
242 | } |
243 | |
244 | static const struct file_operations sched_feat_fops = { |
245 | .open = sched_feat_open, |
246 | .write = sched_feat_write, |
247 | .read = seq_read, |
248 | .llseek = seq_lseek, |
249 | .release = single_release, |
250 | }; |
251 | |
252 | static __init int sched_init_debug(void) |
253 | { |
254 | debugfs_create_file("sched_features", 0644, NULL, NULL, |
255 | &sched_feat_fops); |
256 | |
257 | return 0; |
258 | } |
259 | late_initcall(sched_init_debug); |
260 | #endif /* CONFIG_SCHED_DEBUG */ |
261 | |
262 | /* |
263 | * Number of tasks to iterate in a single balance run. |
264 | * Limited because this is done with IRQs disabled. |
265 | */ |
266 | const_debug unsigned int sysctl_sched_nr_migrate = 32; |
267 | |
268 | /* |
269 | * period over which we average the RT time consumption, measured |
270 | * in ms. |
271 | * |
272 | * default: 1s |
273 | */ |
274 | const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; |
275 | |
276 | /* |
277 | * period over which we measure -rt task cpu usage in us. |
278 | * default: 1s |
279 | */ |
280 | unsigned int sysctl_sched_rt_period = 1000000; |
281 | |
282 | __read_mostly int scheduler_running; |
283 | |
284 | /* |
285 | * part of the period that we allow rt tasks to run in us. |
286 | * default: 0.95s |
287 | */ |
288 | int sysctl_sched_rt_runtime = 950000; |
289 | |
290 | |
291 | |
292 | /* |
293 | * __task_rq_lock - lock the rq @p resides on. |
294 | */ |
295 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
296 | __acquires(rq->lock) |
297 | { |
298 | struct rq *rq; |
299 | |
300 | lockdep_assert_held(&p->pi_lock); |
301 | |
302 | for (;;) { |
303 | rq = task_rq(p); |
304 | raw_spin_lock(&rq->lock); |
305 | if (likely(rq == task_rq(p))) |
306 | return rq; |
307 | raw_spin_unlock(&rq->lock); |
308 | } |
309 | } |
310 | |
311 | /* |
312 | * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. |
313 | */ |
314 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
315 | __acquires(p->pi_lock) |
316 | __acquires(rq->lock) |
317 | { |
318 | struct rq *rq; |
319 | |
320 | for (;;) { |
321 | raw_spin_lock_irqsave(&p->pi_lock, *flags); |
322 | rq = task_rq(p); |
323 | raw_spin_lock(&rq->lock); |
324 | if (likely(rq == task_rq(p))) |
325 | return rq; |
326 | raw_spin_unlock(&rq->lock); |
327 | raw_spin_unlock_irqrestore(&p->pi_lock, *flags); |
328 | } |
329 | } |
330 | |
331 | static void __task_rq_unlock(struct rq *rq) |
332 | __releases(rq->lock) |
333 | { |
334 | raw_spin_unlock(&rq->lock); |
335 | } |
336 | |
337 | static inline void |
338 | task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) |
339 | __releases(rq->lock) |
340 | __releases(p->pi_lock) |
341 | { |
342 | raw_spin_unlock(&rq->lock); |
343 | raw_spin_unlock_irqrestore(&p->pi_lock, *flags); |
344 | } |
345 | |
346 | /* |
347 | * this_rq_lock - lock this runqueue and disable interrupts. |
348 | */ |
349 | static struct rq *this_rq_lock(void) |
350 | __acquires(rq->lock) |
351 | { |
352 | struct rq *rq; |
353 | |
354 | local_irq_disable(); |
355 | rq = this_rq(); |
356 | raw_spin_lock(&rq->lock); |
357 | |
358 | return rq; |
359 | } |
360 | |
361 | #ifdef CONFIG_SCHED_HRTICK |
362 | /* |
363 | * Use HR-timers to deliver accurate preemption points. |
364 | * |
365 | * Its all a bit involved since we cannot program an hrt while holding the |
366 | * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a |
367 | * reschedule event. |
368 | * |
369 | * When we get rescheduled we reprogram the hrtick_timer outside of the |
370 | * rq->lock. |
371 | */ |
372 | |
373 | static void hrtick_clear(struct rq *rq) |
374 | { |
375 | if (hrtimer_active(&rq->hrtick_timer)) |
376 | hrtimer_cancel(&rq->hrtick_timer); |
377 | } |
378 | |
379 | /* |
380 | * High-resolution timer tick. |
381 | * Runs from hardirq context with interrupts disabled. |
382 | */ |
383 | static enum hrtimer_restart hrtick(struct hrtimer *timer) |
384 | { |
385 | struct rq *rq = container_of(timer, struct rq, hrtick_timer); |
386 | |
387 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); |
388 | |
389 | raw_spin_lock(&rq->lock); |
390 | update_rq_clock(rq); |
391 | rq->curr->sched_class->task_tick(rq, rq->curr, 1); |
392 | raw_spin_unlock(&rq->lock); |
393 | |
394 | return HRTIMER_NORESTART; |
395 | } |
396 | |
397 | #ifdef CONFIG_SMP |
398 | /* |
399 | * called from hardirq (IPI) context |
400 | */ |
401 | static void __hrtick_start(void *arg) |
402 | { |
403 | struct rq *rq = arg; |
404 | |
405 | raw_spin_lock(&rq->lock); |
406 | hrtimer_restart(&rq->hrtick_timer); |
407 | rq->hrtick_csd_pending = 0; |
408 | raw_spin_unlock(&rq->lock); |
409 | } |
410 | |
411 | /* |
412 | * Called to set the hrtick timer state. |
413 | * |
414 | * called with rq->lock held and irqs disabled |
415 | */ |
416 | void hrtick_start(struct rq *rq, u64 delay) |
417 | { |
418 | struct hrtimer *timer = &rq->hrtick_timer; |
419 | ktime_t time = ktime_add_ns(timer->base->get_time(), delay); |
420 | |
421 | hrtimer_set_expires(timer, time); |
422 | |
423 | if (rq == this_rq()) { |
424 | hrtimer_restart(timer); |
425 | } else if (!rq->hrtick_csd_pending) { |
426 | __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); |
427 | rq->hrtick_csd_pending = 1; |
428 | } |
429 | } |
430 | |
431 | static int |
432 | hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) |
433 | { |
434 | int cpu = (int)(long)hcpu; |
435 | |
436 | switch (action) { |
437 | case CPU_UP_CANCELED: |
438 | case CPU_UP_CANCELED_FROZEN: |
439 | case CPU_DOWN_PREPARE: |
440 | case CPU_DOWN_PREPARE_FROZEN: |
441 | case CPU_DEAD: |
442 | case CPU_DEAD_FROZEN: |
443 | hrtick_clear(cpu_rq(cpu)); |
444 | return NOTIFY_OK; |
445 | } |
446 | |
447 | return NOTIFY_DONE; |
448 | } |
449 | |
450 | static __init void init_hrtick(void) |
451 | { |
452 | hotcpu_notifier(hotplug_hrtick, 0); |
453 | } |
454 | #else |
455 | /* |
456 | * Called to set the hrtick timer state. |
457 | * |
458 | * called with rq->lock held and irqs disabled |
459 | */ |
460 | void hrtick_start(struct rq *rq, u64 delay) |
461 | { |
462 | __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, |
463 | HRTIMER_MODE_REL_PINNED, 0); |
464 | } |
465 | |
466 | static inline void init_hrtick(void) |
467 | { |
468 | } |
469 | #endif /* CONFIG_SMP */ |
470 | |
471 | static void init_rq_hrtick(struct rq *rq) |
472 | { |
473 | #ifdef CONFIG_SMP |
474 | rq->hrtick_csd_pending = 0; |
475 | |
476 | rq->hrtick_csd.flags = 0; |
477 | rq->hrtick_csd.func = __hrtick_start; |
478 | rq->hrtick_csd.info = rq; |
479 | #endif |
480 | |
481 | hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
482 | rq->hrtick_timer.function = hrtick; |
483 | } |
484 | #else /* CONFIG_SCHED_HRTICK */ |
485 | static inline void hrtick_clear(struct rq *rq) |
486 | { |
487 | } |
488 | |
489 | static inline void init_rq_hrtick(struct rq *rq) |
490 | { |
491 | } |
492 | |
493 | static inline void init_hrtick(void) |
494 | { |
495 | } |
496 | #endif /* CONFIG_SCHED_HRTICK */ |
497 | |
498 | /* |
499 | * resched_task - mark a task 'to be rescheduled now'. |
500 | * |
501 | * On UP this means the setting of the need_resched flag, on SMP it |
502 | * might also involve a cross-CPU call to trigger the scheduler on |
503 | * the target CPU. |
504 | */ |
505 | #ifdef CONFIG_SMP |
506 | |
507 | #ifndef tsk_is_polling |
508 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) |
509 | #endif |
510 | |
511 | void resched_task(struct task_struct *p) |
512 | { |
513 | int cpu; |
514 | |
515 | assert_raw_spin_locked(&task_rq(p)->lock); |
516 | |
517 | if (test_tsk_need_resched(p)) |
518 | return; |
519 | |
520 | set_tsk_need_resched(p); |
521 | |
522 | cpu = task_cpu(p); |
523 | if (cpu == smp_processor_id()) |
524 | return; |
525 | |
526 | /* NEED_RESCHED must be visible before we test polling */ |
527 | smp_mb(); |
528 | if (!tsk_is_polling(p)) |
529 | smp_send_reschedule(cpu); |
530 | } |
531 | |
532 | void resched_cpu(int cpu) |
533 | { |
534 | struct rq *rq = cpu_rq(cpu); |
535 | unsigned long flags; |
536 | |
537 | if (!raw_spin_trylock_irqsave(&rq->lock, flags)) |
538 | return; |
539 | resched_task(cpu_curr(cpu)); |
540 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
541 | } |
542 | |
543 | #ifdef CONFIG_NO_HZ |
544 | /* |
545 | * In the semi idle case, use the nearest busy cpu for migrating timers |
546 | * from an idle cpu. This is good for power-savings. |
547 | * |
548 | * We don't do similar optimization for completely idle system, as |
549 | * selecting an idle cpu will add more delays to the timers than intended |
550 | * (as that cpu's timer base may not be uptodate wrt jiffies etc). |
551 | */ |
552 | int get_nohz_timer_target(void) |
553 | { |
554 | int cpu = smp_processor_id(); |
555 | int i; |
556 | struct sched_domain *sd; |
557 | |
558 | rcu_read_lock(); |
559 | for_each_domain(cpu, sd) { |
560 | for_each_cpu(i, sched_domain_span(sd)) { |
561 | if (!idle_cpu(i)) { |
562 | cpu = i; |
563 | goto unlock; |
564 | } |
565 | } |
566 | } |
567 | unlock: |
568 | rcu_read_unlock(); |
569 | return cpu; |
570 | } |
571 | /* |
572 | * When add_timer_on() enqueues a timer into the timer wheel of an |
573 | * idle CPU then this timer might expire before the next timer event |
574 | * which is scheduled to wake up that CPU. In case of a completely |
575 | * idle system the next event might even be infinite time into the |
576 | * future. wake_up_idle_cpu() ensures that the CPU is woken up and |
577 | * leaves the inner idle loop so the newly added timer is taken into |
578 | * account when the CPU goes back to idle and evaluates the timer |
579 | * wheel for the next timer event. |
580 | */ |
581 | void wake_up_idle_cpu(int cpu) |
582 | { |
583 | struct rq *rq = cpu_rq(cpu); |
584 | |
585 | if (cpu == smp_processor_id()) |
586 | return; |
587 | |
588 | /* |
589 | * This is safe, as this function is called with the timer |
590 | * wheel base lock of (cpu) held. When the CPU is on the way |
591 | * to idle and has not yet set rq->curr to idle then it will |
592 | * be serialized on the timer wheel base lock and take the new |
593 | * timer into account automatically. |
594 | */ |
595 | if (rq->curr != rq->idle) |
596 | return; |
597 | |
598 | /* |
599 | * We can set TIF_RESCHED on the idle task of the other CPU |
600 | * lockless. The worst case is that the other CPU runs the |
601 | * idle task through an additional NOOP schedule() |
602 | */ |
603 | set_tsk_need_resched(rq->idle); |
604 | |
605 | /* NEED_RESCHED must be visible before we test polling */ |
606 | smp_mb(); |
607 | if (!tsk_is_polling(rq->idle)) |
608 | smp_send_reschedule(cpu); |
609 | } |
610 | |
611 | static inline bool got_nohz_idle_kick(void) |
612 | { |
613 | int cpu = smp_processor_id(); |
614 | return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); |
615 | } |
616 | |
617 | #else /* CONFIG_NO_HZ */ |
618 | |
619 | static inline bool got_nohz_idle_kick(void) |
620 | { |
621 | return false; |
622 | } |
623 | |
624 | #endif /* CONFIG_NO_HZ */ |
625 | |
626 | void sched_avg_update(struct rq *rq) |
627 | { |
628 | s64 period = sched_avg_period(); |
629 | |
630 | while ((s64)(rq->clock - rq->age_stamp) > period) { |
631 | /* |
632 | * Inline assembly required to prevent the compiler |
633 | * optimising this loop into a divmod call. |
634 | * See __iter_div_u64_rem() for another example of this. |
635 | */ |
636 | asm("" : "+rm" (rq->age_stamp)); |
637 | rq->age_stamp += period; |
638 | rq->rt_avg /= 2; |
639 | } |
640 | } |
641 | |
642 | #else /* !CONFIG_SMP */ |
643 | void resched_task(struct task_struct *p) |
644 | { |
645 | assert_raw_spin_locked(&task_rq(p)->lock); |
646 | set_tsk_need_resched(p); |
647 | } |
648 | #endif /* CONFIG_SMP */ |
649 | |
650 | #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ |
651 | (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) |
652 | /* |
653 | * Iterate task_group tree rooted at *from, calling @down when first entering a |
654 | * node and @up when leaving it for the final time. |
655 | * |
656 | * Caller must hold rcu_lock or sufficient equivalent. |
657 | */ |
658 | int walk_tg_tree_from(struct task_group *from, |
659 | tg_visitor down, tg_visitor up, void *data) |
660 | { |
661 | struct task_group *parent, *child; |
662 | int ret; |
663 | |
664 | parent = from; |
665 | |
666 | down: |
667 | ret = (*down)(parent, data); |
668 | if (ret) |
669 | goto out; |
670 | list_for_each_entry_rcu(child, &parent->children, siblings) { |
671 | parent = child; |
672 | goto down; |
673 | |
674 | up: |
675 | continue; |
676 | } |
677 | ret = (*up)(parent, data); |
678 | if (ret || parent == from) |
679 | goto out; |
680 | |
681 | child = parent; |
682 | parent = parent->parent; |
683 | if (parent) |
684 | goto up; |
685 | out: |
686 | return ret; |
687 | } |
688 | |
689 | int tg_nop(struct task_group *tg, void *data) |
690 | { |
691 | return 0; |
692 | } |
693 | #endif |
694 | |
695 | static void set_load_weight(struct task_struct *p) |
696 | { |
697 | int prio = p->static_prio - MAX_RT_PRIO; |
698 | struct load_weight *load = &p->se.load; |
699 | |
700 | /* |
701 | * SCHED_IDLE tasks get minimal weight: |
702 | */ |
703 | if (p->policy == SCHED_IDLE) { |
704 | load->weight = scale_load(WEIGHT_IDLEPRIO); |
705 | load->inv_weight = WMULT_IDLEPRIO; |
706 | return; |
707 | } |
708 | |
709 | load->weight = scale_load(prio_to_weight[prio]); |
710 | load->inv_weight = prio_to_wmult[prio]; |
711 | } |
712 | |
713 | static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) |
714 | { |
715 | update_rq_clock(rq); |
716 | sched_info_queued(p); |
717 | p->sched_class->enqueue_task(rq, p, flags); |
718 | } |
719 | |
720 | static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) |
721 | { |
722 | update_rq_clock(rq); |
723 | sched_info_dequeued(p); |
724 | p->sched_class->dequeue_task(rq, p, flags); |
725 | } |
726 | |
727 | void activate_task(struct rq *rq, struct task_struct *p, int flags) |
728 | { |
729 | if (task_contributes_to_load(p)) |
730 | rq->nr_uninterruptible--; |
731 | |
732 | enqueue_task(rq, p, flags); |
733 | } |
734 | |
735 | void deactivate_task(struct rq *rq, struct task_struct *p, int flags) |
736 | { |
737 | if (task_contributes_to_load(p)) |
738 | rq->nr_uninterruptible++; |
739 | |
740 | dequeue_task(rq, p, flags); |
741 | } |
742 | |
743 | #ifdef CONFIG_IRQ_TIME_ACCOUNTING |
744 | |
745 | /* |
746 | * There are no locks covering percpu hardirq/softirq time. |
747 | * They are only modified in account_system_vtime, on corresponding CPU |
748 | * with interrupts disabled. So, writes are safe. |
749 | * They are read and saved off onto struct rq in update_rq_clock(). |
750 | * This may result in other CPU reading this CPU's irq time and can |
751 | * race with irq/account_system_vtime on this CPU. We would either get old |
752 | * or new value with a side effect of accounting a slice of irq time to wrong |
753 | * task when irq is in progress while we read rq->clock. That is a worthy |
754 | * compromise in place of having locks on each irq in account_system_time. |
755 | */ |
756 | static DEFINE_PER_CPU(u64, cpu_hardirq_time); |
757 | static DEFINE_PER_CPU(u64, cpu_softirq_time); |
758 | |
759 | static DEFINE_PER_CPU(u64, irq_start_time); |
760 | static int sched_clock_irqtime; |
761 | |
762 | void enable_sched_clock_irqtime(void) |
763 | { |
764 | sched_clock_irqtime = 1; |
765 | } |
766 | |
767 | void disable_sched_clock_irqtime(void) |
768 | { |
769 | sched_clock_irqtime = 0; |
770 | } |
771 | |
772 | #ifndef CONFIG_64BIT |
773 | static DEFINE_PER_CPU(seqcount_t, irq_time_seq); |
774 | |
775 | static inline void irq_time_write_begin(void) |
776 | { |
777 | __this_cpu_inc(irq_time_seq.sequence); |
778 | smp_wmb(); |
779 | } |
780 | |
781 | static inline void irq_time_write_end(void) |
782 | { |
783 | smp_wmb(); |
784 | __this_cpu_inc(irq_time_seq.sequence); |
785 | } |
786 | |
787 | static inline u64 irq_time_read(int cpu) |
788 | { |
789 | u64 irq_time; |
790 | unsigned seq; |
791 | |
792 | do { |
793 | seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu)); |
794 | irq_time = per_cpu(cpu_softirq_time, cpu) + |
795 | per_cpu(cpu_hardirq_time, cpu); |
796 | } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq)); |
797 | |
798 | return irq_time; |
799 | } |
800 | #else /* CONFIG_64BIT */ |
801 | static inline void irq_time_write_begin(void) |
802 | { |
803 | } |
804 | |
805 | static inline void irq_time_write_end(void) |
806 | { |
807 | } |
808 | |
809 | static inline u64 irq_time_read(int cpu) |
810 | { |
811 | return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu); |
812 | } |
813 | #endif /* CONFIG_64BIT */ |
814 | |
815 | /* |
816 | * Called before incrementing preempt_count on {soft,}irq_enter |
817 | * and before decrementing preempt_count on {soft,}irq_exit. |
818 | */ |
819 | void account_system_vtime(struct task_struct *curr) |
820 | { |
821 | unsigned long flags; |
822 | s64 delta; |
823 | int cpu; |
824 | |
825 | if (!sched_clock_irqtime) |
826 | return; |
827 | |
828 | local_irq_save(flags); |
829 | |
830 | cpu = smp_processor_id(); |
831 | delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time); |
832 | __this_cpu_add(irq_start_time, delta); |
833 | |
834 | irq_time_write_begin(); |
835 | /* |
836 | * We do not account for softirq time from ksoftirqd here. |
837 | * We want to continue accounting softirq time to ksoftirqd thread |
838 | * in that case, so as not to confuse scheduler with a special task |
839 | * that do not consume any time, but still wants to run. |
840 | */ |
841 | if (hardirq_count()) |
842 | __this_cpu_add(cpu_hardirq_time, delta); |
843 | else if (in_serving_softirq() && curr != this_cpu_ksoftirqd()) |
844 | __this_cpu_add(cpu_softirq_time, delta); |
845 | |
846 | irq_time_write_end(); |
847 | local_irq_restore(flags); |
848 | } |
849 | EXPORT_SYMBOL_GPL(account_system_vtime); |
850 | |
851 | #endif /* CONFIG_IRQ_TIME_ACCOUNTING */ |
852 | |
853 | #ifdef CONFIG_PARAVIRT |
854 | static inline u64 steal_ticks(u64 steal) |
855 | { |
856 | if (unlikely(steal > NSEC_PER_SEC)) |
857 | return div_u64(steal, TICK_NSEC); |
858 | |
859 | return __iter_div_u64_rem(steal, TICK_NSEC, &steal); |
860 | } |
861 | #endif |
862 | |
863 | static void update_rq_clock_task(struct rq *rq, s64 delta) |
864 | { |
865 | /* |
866 | * In theory, the compile should just see 0 here, and optimize out the call |
867 | * to sched_rt_avg_update. But I don't trust it... |
868 | */ |
869 | #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) |
870 | s64 steal = 0, irq_delta = 0; |
871 | #endif |
872 | #ifdef CONFIG_IRQ_TIME_ACCOUNTING |
873 | irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; |
874 | |
875 | /* |
876 | * Since irq_time is only updated on {soft,}irq_exit, we might run into |
877 | * this case when a previous update_rq_clock() happened inside a |
878 | * {soft,}irq region. |
879 | * |
880 | * When this happens, we stop ->clock_task and only update the |
881 | * prev_irq_time stamp to account for the part that fit, so that a next |
882 | * update will consume the rest. This ensures ->clock_task is |
883 | * monotonic. |
884 | * |
885 | * It does however cause some slight miss-attribution of {soft,}irq |
886 | * time, a more accurate solution would be to update the irq_time using |
887 | * the current rq->clock timestamp, except that would require using |
888 | * atomic ops. |
889 | */ |
890 | if (irq_delta > delta) |
891 | irq_delta = delta; |
892 | |
893 | rq->prev_irq_time += irq_delta; |
894 | delta -= irq_delta; |
895 | #endif |
896 | #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING |
897 | if (static_key_false((¶virt_steal_rq_enabled))) { |
898 | u64 st; |
899 | |
900 | steal = paravirt_steal_clock(cpu_of(rq)); |
901 | steal -= rq->prev_steal_time_rq; |
902 | |
903 | if (unlikely(steal > delta)) |
904 | steal = delta; |
905 | |
906 | st = steal_ticks(steal); |
907 | steal = st * TICK_NSEC; |
908 | |
909 | rq->prev_steal_time_rq += steal; |
910 | |
911 | delta -= steal; |
912 | } |
913 | #endif |
914 | |
915 | rq->clock_task += delta; |
916 | |
917 | #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) |
918 | if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) |
919 | sched_rt_avg_update(rq, irq_delta + steal); |
920 | #endif |
921 | } |
922 | |
923 | #ifdef CONFIG_IRQ_TIME_ACCOUNTING |
924 | static int irqtime_account_hi_update(void) |
925 | { |
926 | u64 *cpustat = kcpustat_this_cpu->cpustat; |
927 | unsigned long flags; |
928 | u64 latest_ns; |
929 | int ret = 0; |
930 | |
931 | local_irq_save(flags); |
932 | latest_ns = this_cpu_read(cpu_hardirq_time); |
933 | if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ]) |
934 | ret = 1; |
935 | local_irq_restore(flags); |
936 | return ret; |
937 | } |
938 | |
939 | static int irqtime_account_si_update(void) |
940 | { |
941 | u64 *cpustat = kcpustat_this_cpu->cpustat; |
942 | unsigned long flags; |
943 | u64 latest_ns; |
944 | int ret = 0; |
945 | |
946 | local_irq_save(flags); |
947 | latest_ns = this_cpu_read(cpu_softirq_time); |
948 | if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ]) |
949 | ret = 1; |
950 | local_irq_restore(flags); |
951 | return ret; |
952 | } |
953 | |
954 | #else /* CONFIG_IRQ_TIME_ACCOUNTING */ |
955 | |
956 | #define sched_clock_irqtime (0) |
957 | |
958 | #endif |
959 | |
960 | void sched_set_stop_task(int cpu, struct task_struct *stop) |
961 | { |
962 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; |
963 | struct task_struct *old_stop = cpu_rq(cpu)->stop; |
964 | |
965 | if (stop) { |
966 | /* |
967 | * Make it appear like a SCHED_FIFO task, its something |
968 | * userspace knows about and won't get confused about. |
969 | * |
970 | * Also, it will make PI more or less work without too |
971 | * much confusion -- but then, stop work should not |
972 | * rely on PI working anyway. |
973 | */ |
974 | sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); |
975 | |
976 | stop->sched_class = &stop_sched_class; |
977 | } |
978 | |
979 | cpu_rq(cpu)->stop = stop; |
980 | |
981 | if (old_stop) { |
982 | /* |
983 | * Reset it back to a normal scheduling class so that |
984 | * it can die in pieces. |
985 | */ |
986 | old_stop->sched_class = &rt_sched_class; |
987 | } |
988 | } |
989 | |
990 | /* |
991 | * __normal_prio - return the priority that is based on the static prio |
992 | */ |
993 | static inline int __normal_prio(struct task_struct *p) |
994 | { |
995 | return p->static_prio; |
996 | } |
997 | |
998 | /* |
999 | * Calculate the expected normal priority: i.e. priority |
1000 | * without taking RT-inheritance into account. Might be |
1001 | * boosted by interactivity modifiers. Changes upon fork, |
1002 | * setprio syscalls, and whenever the interactivity |
1003 | * estimator recalculates. |
1004 | */ |
1005 | static inline int normal_prio(struct task_struct *p) |
1006 | { |
1007 | int prio; |
1008 | |
1009 | if (task_has_rt_policy(p)) |
1010 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
1011 | else |
1012 | prio = __normal_prio(p); |
1013 | return prio; |
1014 | } |
1015 | |
1016 | /* |
1017 | * Calculate the current priority, i.e. the priority |
1018 | * taken into account by the scheduler. This value might |
1019 | * be boosted by RT tasks, or might be boosted by |
1020 | * interactivity modifiers. Will be RT if the task got |
1021 | * RT-boosted. If not then it returns p->normal_prio. |
1022 | */ |
1023 | static int effective_prio(struct task_struct *p) |
1024 | { |
1025 | p->normal_prio = normal_prio(p); |
1026 | /* |
1027 | * If we are RT tasks or we were boosted to RT priority, |
1028 | * keep the priority unchanged. Otherwise, update priority |
1029 | * to the normal priority: |
1030 | */ |
1031 | if (!rt_prio(p->prio)) |
1032 | return p->normal_prio; |
1033 | return p->prio; |
1034 | } |
1035 | |
1036 | /** |
1037 | * task_curr - is this task currently executing on a CPU? |
1038 | * @p: the task in question. |
1039 | */ |
1040 | inline int task_curr(const struct task_struct *p) |
1041 | { |
1042 | return cpu_curr(task_cpu(p)) == p; |
1043 | } |
1044 | |
1045 | static inline void check_class_changed(struct rq *rq, struct task_struct *p, |
1046 | const struct sched_class *prev_class, |
1047 | int oldprio) |
1048 | { |
1049 | if (prev_class != p->sched_class) { |
1050 | if (prev_class->switched_from) |
1051 | prev_class->switched_from(rq, p); |
1052 | p->sched_class->switched_to(rq, p); |
1053 | } else if (oldprio != p->prio) |
1054 | p->sched_class->prio_changed(rq, p, oldprio); |
1055 | } |
1056 | |
1057 | void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) |
1058 | { |
1059 | const struct sched_class *class; |
1060 | |
1061 | if (p->sched_class == rq->curr->sched_class) { |
1062 | rq->curr->sched_class->check_preempt_curr(rq, p, flags); |
1063 | } else { |
1064 | for_each_class(class) { |
1065 | if (class == rq->curr->sched_class) |
1066 | break; |
1067 | if (class == p->sched_class) { |
1068 | resched_task(rq->curr); |
1069 | break; |
1070 | } |
1071 | } |
1072 | } |
1073 | |
1074 | /* |
1075 | * A queue event has occurred, and we're going to schedule. In |
1076 | * this case, we can save a useless back to back clock update. |
1077 | */ |
1078 | if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) |
1079 | rq->skip_clock_update = 1; |
1080 | } |
1081 | |
1082 | #ifdef CONFIG_SMP |
1083 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
1084 | { |
1085 | #ifdef CONFIG_SCHED_DEBUG |
1086 | /* |
1087 | * We should never call set_task_cpu() on a blocked task, |
1088 | * ttwu() will sort out the placement. |
1089 | */ |
1090 | WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && |
1091 | !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); |
1092 | |
1093 | #ifdef CONFIG_LOCKDEP |
1094 | /* |
1095 | * The caller should hold either p->pi_lock or rq->lock, when changing |
1096 | * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. |
1097 | * |
1098 | * sched_move_task() holds both and thus holding either pins the cgroup, |
1099 | * see set_task_rq(). |
1100 | * |
1101 | * Furthermore, all task_rq users should acquire both locks, see |
1102 | * task_rq_lock(). |
1103 | */ |
1104 | WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || |
1105 | lockdep_is_held(&task_rq(p)->lock))); |
1106 | #endif |
1107 | #endif |
1108 | |
1109 | trace_sched_migrate_task(p, new_cpu); |
1110 | |
1111 | if (task_cpu(p) != new_cpu) { |
1112 | p->se.nr_migrations++; |
1113 | perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); |
1114 | } |
1115 | |
1116 | __set_task_cpu(p, new_cpu); |
1117 | } |
1118 | |
1119 | struct migration_arg { |
1120 | struct task_struct *task; |
1121 | int dest_cpu; |
1122 | }; |
1123 | |
1124 | static int migration_cpu_stop(void *data); |
1125 | |
1126 | /* |
1127 | * wait_task_inactive - wait for a thread to unschedule. |
1128 | * |
1129 | * If @match_state is nonzero, it's the @p->state value just checked and |
1130 | * not expected to change. If it changes, i.e. @p might have woken up, |
1131 | * then return zero. When we succeed in waiting for @p to be off its CPU, |
1132 | * we return a positive number (its total switch count). If a second call |
1133 | * a short while later returns the same number, the caller can be sure that |
1134 | * @p has remained unscheduled the whole time. |
1135 | * |
1136 | * The caller must ensure that the task *will* unschedule sometime soon, |
1137 | * else this function might spin for a *long* time. This function can't |
1138 | * be called with interrupts off, or it may introduce deadlock with |
1139 | * smp_call_function() if an IPI is sent by the same process we are |
1140 | * waiting to become inactive. |
1141 | */ |
1142 | unsigned long wait_task_inactive(struct task_struct *p, long match_state) |
1143 | { |
1144 | unsigned long flags; |
1145 | int running, on_rq; |
1146 | unsigned long ncsw; |
1147 | struct rq *rq; |
1148 | |
1149 | for (;;) { |
1150 | /* |
1151 | * We do the initial early heuristics without holding |
1152 | * any task-queue locks at all. We'll only try to get |
1153 | * the runqueue lock when things look like they will |
1154 | * work out! |
1155 | */ |
1156 | rq = task_rq(p); |
1157 | |
1158 | /* |
1159 | * If the task is actively running on another CPU |
1160 | * still, just relax and busy-wait without holding |
1161 | * any locks. |
1162 | * |
1163 | * NOTE! Since we don't hold any locks, it's not |
1164 | * even sure that "rq" stays as the right runqueue! |
1165 | * But we don't care, since "task_running()" will |
1166 | * return false if the runqueue has changed and p |
1167 | * is actually now running somewhere else! |
1168 | */ |
1169 | while (task_running(rq, p)) { |
1170 | if (match_state && unlikely(p->state != match_state)) |
1171 | return 0; |
1172 | cpu_relax(); |
1173 | } |
1174 | |
1175 | /* |
1176 | * Ok, time to look more closely! We need the rq |
1177 | * lock now, to be *sure*. If we're wrong, we'll |
1178 | * just go back and repeat. |
1179 | */ |
1180 | rq = task_rq_lock(p, &flags); |
1181 | trace_sched_wait_task(p); |
1182 | running = task_running(rq, p); |
1183 | on_rq = p->on_rq; |
1184 | ncsw = 0; |
1185 | if (!match_state || p->state == match_state) |
1186 | ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ |
1187 | task_rq_unlock(rq, p, &flags); |
1188 | |
1189 | /* |
1190 | * If it changed from the expected state, bail out now. |
1191 | */ |
1192 | if (unlikely(!ncsw)) |
1193 | break; |
1194 | |
1195 | /* |
1196 | * Was it really running after all now that we |
1197 | * checked with the proper locks actually held? |
1198 | * |
1199 | * Oops. Go back and try again.. |
1200 | */ |
1201 | if (unlikely(running)) { |
1202 | cpu_relax(); |
1203 | continue; |
1204 | } |
1205 | |
1206 | /* |
1207 | * It's not enough that it's not actively running, |
1208 | * it must be off the runqueue _entirely_, and not |
1209 | * preempted! |
1210 | * |
1211 | * So if it was still runnable (but just not actively |
1212 | * running right now), it's preempted, and we should |
1213 | * yield - it could be a while. |
1214 | */ |
1215 | if (unlikely(on_rq)) { |
1216 | ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); |
1217 | |
1218 | set_current_state(TASK_UNINTERRUPTIBLE); |
1219 | schedule_hrtimeout(&to, HRTIMER_MODE_REL); |
1220 | continue; |
1221 | } |
1222 | |
1223 | /* |
1224 | * Ahh, all good. It wasn't running, and it wasn't |
1225 | * runnable, which means that it will never become |
1226 | * running in the future either. We're all done! |
1227 | */ |
1228 | break; |
1229 | } |
1230 | |
1231 | return ncsw; |
1232 | } |
1233 | |
1234 | /*** |
1235 | * kick_process - kick a running thread to enter/exit the kernel |
1236 | * @p: the to-be-kicked thread |
1237 | * |
1238 | * Cause a process which is running on another CPU to enter |
1239 | * kernel-mode, without any delay. (to get signals handled.) |
1240 | * |
1241 | * NOTE: this function doesn't have to take the runqueue lock, |
1242 | * because all it wants to ensure is that the remote task enters |
1243 | * the kernel. If the IPI races and the task has been migrated |
1244 | * to another CPU then no harm is done and the purpose has been |
1245 | * achieved as well. |
1246 | */ |
1247 | void kick_process(struct task_struct *p) |
1248 | { |
1249 | int cpu; |
1250 | |
1251 | preempt_disable(); |
1252 | cpu = task_cpu(p); |
1253 | if ((cpu != smp_processor_id()) && task_curr(p)) |
1254 | smp_send_reschedule(cpu); |
1255 | preempt_enable(); |
1256 | } |
1257 | EXPORT_SYMBOL_GPL(kick_process); |
1258 | #endif /* CONFIG_SMP */ |
1259 | |
1260 | #ifdef CONFIG_SMP |
1261 | /* |
1262 | * ->cpus_allowed is protected by both rq->lock and p->pi_lock |
1263 | */ |
1264 | static int select_fallback_rq(int cpu, struct task_struct *p) |
1265 | { |
1266 | const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu)); |
1267 | enum { cpuset, possible, fail } state = cpuset; |
1268 | int dest_cpu; |
1269 | |
1270 | /* Look for allowed, online CPU in same node. */ |
1271 | for_each_cpu(dest_cpu, nodemask) { |
1272 | if (!cpu_online(dest_cpu)) |
1273 | continue; |
1274 | if (!cpu_active(dest_cpu)) |
1275 | continue; |
1276 | if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) |
1277 | return dest_cpu; |
1278 | } |
1279 | |
1280 | for (;;) { |
1281 | /* Any allowed, online CPU? */ |
1282 | for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { |
1283 | if (!cpu_online(dest_cpu)) |
1284 | continue; |
1285 | if (!cpu_active(dest_cpu)) |
1286 | continue; |
1287 | goto out; |
1288 | } |
1289 | |
1290 | switch (state) { |
1291 | case cpuset: |
1292 | /* No more Mr. Nice Guy. */ |
1293 | cpuset_cpus_allowed_fallback(p); |
1294 | state = possible; |
1295 | break; |
1296 | |
1297 | case possible: |
1298 | do_set_cpus_allowed(p, cpu_possible_mask); |
1299 | state = fail; |
1300 | break; |
1301 | |
1302 | case fail: |
1303 | BUG(); |
1304 | break; |
1305 | } |
1306 | } |
1307 | |
1308 | out: |
1309 | if (state != cpuset) { |
1310 | /* |
1311 | * Don't tell them about moving exiting tasks or |
1312 | * kernel threads (both mm NULL), since they never |
1313 | * leave kernel. |
1314 | */ |
1315 | if (p->mm && printk_ratelimit()) { |
1316 | printk_sched("process %d (%s) no longer affine to cpu%d\n", |
1317 | task_pid_nr(p), p->comm, cpu); |
1318 | } |
1319 | } |
1320 | |
1321 | return dest_cpu; |
1322 | } |
1323 | |
1324 | /* |
1325 | * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. |
1326 | */ |
1327 | static inline |
1328 | int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) |
1329 | { |
1330 | int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags); |
1331 | |
1332 | /* |
1333 | * In order not to call set_task_cpu() on a blocking task we need |
1334 | * to rely on ttwu() to place the task on a valid ->cpus_allowed |
1335 | * cpu. |
1336 | * |
1337 | * Since this is common to all placement strategies, this lives here. |
1338 | * |
1339 | * [ this allows ->select_task() to simply return task_cpu(p) and |
1340 | * not worry about this generic constraint ] |
1341 | */ |
1342 | if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || |
1343 | !cpu_online(cpu))) |
1344 | cpu = select_fallback_rq(task_cpu(p), p); |
1345 | |
1346 | return cpu; |
1347 | } |
1348 | |
1349 | static void update_avg(u64 *avg, u64 sample) |
1350 | { |
1351 | s64 diff = sample - *avg; |
1352 | *avg += diff >> 3; |
1353 | } |
1354 | #endif |
1355 | |
1356 | static void |
1357 | ttwu_stat(struct task_struct *p, int cpu, int wake_flags) |
1358 | { |
1359 | #ifdef CONFIG_SCHEDSTATS |
1360 | struct rq *rq = this_rq(); |
1361 | |
1362 | #ifdef CONFIG_SMP |
1363 | int this_cpu = smp_processor_id(); |
1364 | |
1365 | if (cpu == this_cpu) { |
1366 | schedstat_inc(rq, ttwu_local); |
1367 | schedstat_inc(p, se.statistics.nr_wakeups_local); |
1368 | } else { |
1369 | struct sched_domain *sd; |
1370 | |
1371 | schedstat_inc(p, se.statistics.nr_wakeups_remote); |
1372 | rcu_read_lock(); |
1373 | for_each_domain(this_cpu, sd) { |
1374 | if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
1375 | schedstat_inc(sd, ttwu_wake_remote); |
1376 | break; |
1377 | } |
1378 | } |
1379 | rcu_read_unlock(); |
1380 | } |
1381 | |
1382 | if (wake_flags & WF_MIGRATED) |
1383 | schedstat_inc(p, se.statistics.nr_wakeups_migrate); |
1384 | |
1385 | #endif /* CONFIG_SMP */ |
1386 | |
1387 | schedstat_inc(rq, ttwu_count); |
1388 | schedstat_inc(p, se.statistics.nr_wakeups); |
1389 | |
1390 | if (wake_flags & WF_SYNC) |
1391 | schedstat_inc(p, se.statistics.nr_wakeups_sync); |
1392 | |
1393 | #endif /* CONFIG_SCHEDSTATS */ |
1394 | } |
1395 | |
1396 | static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) |
1397 | { |
1398 | activate_task(rq, p, en_flags); |
1399 | p->on_rq = 1; |
1400 | |
1401 | /* if a worker is waking up, notify workqueue */ |
1402 | if (p->flags & PF_WQ_WORKER) |
1403 | wq_worker_waking_up(p, cpu_of(rq)); |
1404 | } |
1405 | |
1406 | /* |
1407 | * Mark the task runnable and perform wakeup-preemption. |
1408 | */ |
1409 | static void |
1410 | ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) |
1411 | { |
1412 | trace_sched_wakeup(p, true); |
1413 | check_preempt_curr(rq, p, wake_flags); |
1414 | |
1415 | p->state = TASK_RUNNING; |
1416 | #ifdef CONFIG_SMP |
1417 | if (p->sched_class->task_woken) |
1418 | p->sched_class->task_woken(rq, p); |
1419 | |
1420 | if (rq->idle_stamp) { |
1421 | u64 delta = rq->clock - rq->idle_stamp; |
1422 | u64 max = 2*sysctl_sched_migration_cost; |
1423 | |
1424 | if (delta > max) |
1425 | rq->avg_idle = max; |
1426 | else |
1427 | update_avg(&rq->avg_idle, delta); |
1428 | rq->idle_stamp = 0; |
1429 | } |
1430 | #endif |
1431 | } |
1432 | |
1433 | static void |
1434 | ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) |
1435 | { |
1436 | #ifdef CONFIG_SMP |
1437 | if (p->sched_contributes_to_load) |
1438 | rq->nr_uninterruptible--; |
1439 | #endif |
1440 | |
1441 | ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); |
1442 | ttwu_do_wakeup(rq, p, wake_flags); |
1443 | } |
1444 | |
1445 | /* |
1446 | * Called in case the task @p isn't fully descheduled from its runqueue, |
1447 | * in this case we must do a remote wakeup. Its a 'light' wakeup though, |
1448 | * since all we need to do is flip p->state to TASK_RUNNING, since |
1449 | * the task is still ->on_rq. |
1450 | */ |
1451 | static int ttwu_remote(struct task_struct *p, int wake_flags) |
1452 | { |
1453 | struct rq *rq; |
1454 | int ret = 0; |
1455 | |
1456 | rq = __task_rq_lock(p); |
1457 | if (p->on_rq) { |
1458 | ttwu_do_wakeup(rq, p, wake_flags); |
1459 | ret = 1; |
1460 | } |
1461 | __task_rq_unlock(rq); |
1462 | |
1463 | return ret; |
1464 | } |
1465 | |
1466 | #ifdef CONFIG_SMP |
1467 | static void sched_ttwu_pending(void) |
1468 | { |
1469 | struct rq *rq = this_rq(); |
1470 | struct llist_node *llist = llist_del_all(&rq->wake_list); |
1471 | struct task_struct *p; |
1472 | |
1473 | raw_spin_lock(&rq->lock); |
1474 | |
1475 | while (llist) { |
1476 | p = llist_entry(llist, struct task_struct, wake_entry); |
1477 | llist = llist_next(llist); |
1478 | ttwu_do_activate(rq, p, 0); |
1479 | } |
1480 | |
1481 | raw_spin_unlock(&rq->lock); |
1482 | } |
1483 | |
1484 | void scheduler_ipi(void) |
1485 | { |
1486 | if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) |
1487 | return; |
1488 | |
1489 | /* |
1490 | * Not all reschedule IPI handlers call irq_enter/irq_exit, since |
1491 | * traditionally all their work was done from the interrupt return |
1492 | * path. Now that we actually do some work, we need to make sure |
1493 | * we do call them. |
1494 | * |
1495 | * Some archs already do call them, luckily irq_enter/exit nest |
1496 | * properly. |
1497 | * |
1498 | * Arguably we should visit all archs and update all handlers, |
1499 | * however a fair share of IPIs are still resched only so this would |
1500 | * somewhat pessimize the simple resched case. |
1501 | */ |
1502 | irq_enter(); |
1503 | sched_ttwu_pending(); |
1504 | |
1505 | /* |
1506 | * Check if someone kicked us for doing the nohz idle load balance. |
1507 | */ |
1508 | if (unlikely(got_nohz_idle_kick() && !need_resched())) { |
1509 | this_rq()->idle_balance = 1; |
1510 | raise_softirq_irqoff(SCHED_SOFTIRQ); |
1511 | } |
1512 | irq_exit(); |
1513 | } |
1514 | |
1515 | static void ttwu_queue_remote(struct task_struct *p, int cpu) |
1516 | { |
1517 | if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) |
1518 | smp_send_reschedule(cpu); |
1519 | } |
1520 | |
1521 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1522 | static int ttwu_activate_remote(struct task_struct *p, int wake_flags) |
1523 | { |
1524 | struct rq *rq; |
1525 | int ret = 0; |
1526 | |
1527 | rq = __task_rq_lock(p); |
1528 | if (p->on_cpu) { |
1529 | ttwu_activate(rq, p, ENQUEUE_WAKEUP); |
1530 | ttwu_do_wakeup(rq, p, wake_flags); |
1531 | ret = 1; |
1532 | } |
1533 | __task_rq_unlock(rq); |
1534 | |
1535 | return ret; |
1536 | |
1537 | } |
1538 | #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ |
1539 | |
1540 | bool cpus_share_cache(int this_cpu, int that_cpu) |
1541 | { |
1542 | return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); |
1543 | } |
1544 | #endif /* CONFIG_SMP */ |
1545 | |
1546 | static void ttwu_queue(struct task_struct *p, int cpu) |
1547 | { |
1548 | struct rq *rq = cpu_rq(cpu); |
1549 | |
1550 | #if defined(CONFIG_SMP) |
1551 | if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { |
1552 | sched_clock_cpu(cpu); /* sync clocks x-cpu */ |
1553 | ttwu_queue_remote(p, cpu); |
1554 | return; |
1555 | } |
1556 | #endif |
1557 | |
1558 | raw_spin_lock(&rq->lock); |
1559 | ttwu_do_activate(rq, p, 0); |
1560 | raw_spin_unlock(&rq->lock); |
1561 | } |
1562 | |
1563 | /** |
1564 | * try_to_wake_up - wake up a thread |
1565 | * @p: the thread to be awakened |
1566 | * @state: the mask of task states that can be woken |
1567 | * @wake_flags: wake modifier flags (WF_*) |
1568 | * |
1569 | * Put it on the run-queue if it's not already there. The "current" |
1570 | * thread is always on the run-queue (except when the actual |
1571 | * re-schedule is in progress), and as such you're allowed to do |
1572 | * the simpler "current->state = TASK_RUNNING" to mark yourself |
1573 | * runnable without the overhead of this. |
1574 | * |
1575 | * Returns %true if @p was woken up, %false if it was already running |
1576 | * or @state didn't match @p's state. |
1577 | */ |
1578 | static int |
1579 | try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) |
1580 | { |
1581 | unsigned long flags; |
1582 | int cpu, success = 0; |
1583 | |
1584 | smp_wmb(); |
1585 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
1586 | if (!(p->state & state)) |
1587 | goto out; |
1588 | |
1589 | success = 1; /* we're going to change ->state */ |
1590 | cpu = task_cpu(p); |
1591 | |
1592 | if (p->on_rq && ttwu_remote(p, wake_flags)) |
1593 | goto stat; |
1594 | |
1595 | #ifdef CONFIG_SMP |
1596 | /* |
1597 | * If the owning (remote) cpu is still in the middle of schedule() with |
1598 | * this task as prev, wait until its done referencing the task. |
1599 | */ |
1600 | while (p->on_cpu) { |
1601 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1602 | /* |
1603 | * In case the architecture enables interrupts in |
1604 | * context_switch(), we cannot busy wait, since that |
1605 | * would lead to deadlocks when an interrupt hits and |
1606 | * tries to wake up @prev. So bail and do a complete |
1607 | * remote wakeup. |
1608 | */ |
1609 | if (ttwu_activate_remote(p, wake_flags)) |
1610 | goto stat; |
1611 | #else |
1612 | cpu_relax(); |
1613 | #endif |
1614 | } |
1615 | /* |
1616 | * Pairs with the smp_wmb() in finish_lock_switch(). |
1617 | */ |
1618 | smp_rmb(); |
1619 | |
1620 | p->sched_contributes_to_load = !!task_contributes_to_load(p); |
1621 | p->state = TASK_WAKING; |
1622 | |
1623 | if (p->sched_class->task_waking) |
1624 | p->sched_class->task_waking(p); |
1625 | |
1626 | cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); |
1627 | if (task_cpu(p) != cpu) { |
1628 | wake_flags |= WF_MIGRATED; |
1629 | set_task_cpu(p, cpu); |
1630 | } |
1631 | #endif /* CONFIG_SMP */ |
1632 | |
1633 | ttwu_queue(p, cpu); |
1634 | stat: |
1635 | ttwu_stat(p, cpu, wake_flags); |
1636 | out: |
1637 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1638 | |
1639 | return success; |
1640 | } |
1641 | |
1642 | /** |
1643 | * try_to_wake_up_local - try to wake up a local task with rq lock held |
1644 | * @p: the thread to be awakened |
1645 | * |
1646 | * Put @p on the run-queue if it's not already there. The caller must |
1647 | * ensure that this_rq() is locked, @p is bound to this_rq() and not |
1648 | * the current task. |
1649 | */ |
1650 | static void try_to_wake_up_local(struct task_struct *p) |
1651 | { |
1652 | struct rq *rq = task_rq(p); |
1653 | |
1654 | BUG_ON(rq != this_rq()); |
1655 | BUG_ON(p == current); |
1656 | lockdep_assert_held(&rq->lock); |
1657 | |
1658 | if (!raw_spin_trylock(&p->pi_lock)) { |
1659 | raw_spin_unlock(&rq->lock); |
1660 | raw_spin_lock(&p->pi_lock); |
1661 | raw_spin_lock(&rq->lock); |
1662 | } |
1663 | |
1664 | if (!(p->state & TASK_NORMAL)) |
1665 | goto out; |
1666 | |
1667 | if (!p->on_rq) |
1668 | ttwu_activate(rq, p, ENQUEUE_WAKEUP); |
1669 | |
1670 | ttwu_do_wakeup(rq, p, 0); |
1671 | ttwu_stat(p, smp_processor_id(), 0); |
1672 | out: |
1673 | raw_spin_unlock(&p->pi_lock); |
1674 | } |
1675 | |
1676 | /** |
1677 | * wake_up_process - Wake up a specific process |
1678 | * @p: The process to be woken up. |
1679 | * |
1680 | * Attempt to wake up the nominated process and move it to the set of runnable |
1681 | * processes. Returns 1 if the process was woken up, 0 if it was already |
1682 | * running. |
1683 | * |
1684 | * It may be assumed that this function implies a write memory barrier before |
1685 | * changing the task state if and only if any tasks are woken up. |
1686 | */ |
1687 | int wake_up_process(struct task_struct *p) |
1688 | { |
1689 | return try_to_wake_up(p, TASK_ALL, 0); |
1690 | } |
1691 | EXPORT_SYMBOL(wake_up_process); |
1692 | |
1693 | int wake_up_state(struct task_struct *p, unsigned int state) |
1694 | { |
1695 | return try_to_wake_up(p, state, 0); |
1696 | } |
1697 | |
1698 | /* |
1699 | * Perform scheduler related setup for a newly forked process p. |
1700 | * p is forked by current. |
1701 | * |
1702 | * __sched_fork() is basic setup used by init_idle() too: |
1703 | */ |
1704 | static void __sched_fork(struct task_struct *p) |
1705 | { |
1706 | p->on_rq = 0; |
1707 | |
1708 | p->se.on_rq = 0; |
1709 | p->se.exec_start = 0; |
1710 | p->se.sum_exec_runtime = 0; |
1711 | p->se.prev_sum_exec_runtime = 0; |
1712 | p->se.nr_migrations = 0; |
1713 | p->se.vruntime = 0; |
1714 | INIT_LIST_HEAD(&p->se.group_node); |
1715 | |
1716 | #ifdef CONFIG_SCHEDSTATS |
1717 | memset(&p->se.statistics, 0, sizeof(p->se.statistics)); |
1718 | #endif |
1719 | |
1720 | INIT_LIST_HEAD(&p->rt.run_list); |
1721 | |
1722 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1723 | INIT_HLIST_HEAD(&p->preempt_notifiers); |
1724 | #endif |
1725 | } |
1726 | |
1727 | /* |
1728 | * fork()/clone()-time setup: |
1729 | */ |
1730 | void sched_fork(struct task_struct *p) |
1731 | { |
1732 | unsigned long flags; |
1733 | int cpu = get_cpu(); |
1734 | |
1735 | __sched_fork(p); |
1736 | /* |
1737 | * We mark the process as running here. This guarantees that |
1738 | * nobody will actually run it, and a signal or other external |
1739 | * event cannot wake it up and insert it on the runqueue either. |
1740 | */ |
1741 | p->state = TASK_RUNNING; |
1742 | |
1743 | /* |
1744 | * Make sure we do not leak PI boosting priority to the child. |
1745 | */ |
1746 | p->prio = current->normal_prio; |
1747 | |
1748 | /* |
1749 | * Revert to default priority/policy on fork if requested. |
1750 | */ |
1751 | if (unlikely(p->sched_reset_on_fork)) { |
1752 | if (task_has_rt_policy(p)) { |
1753 | p->policy = SCHED_NORMAL; |
1754 | p->static_prio = NICE_TO_PRIO(0); |
1755 | p->rt_priority = 0; |
1756 | } else if (PRIO_TO_NICE(p->static_prio) < 0) |
1757 | p->static_prio = NICE_TO_PRIO(0); |
1758 | |
1759 | p->prio = p->normal_prio = __normal_prio(p); |
1760 | set_load_weight(p); |
1761 | |
1762 | /* |
1763 | * We don't need the reset flag anymore after the fork. It has |
1764 | * fulfilled its duty: |
1765 | */ |
1766 | p->sched_reset_on_fork = 0; |
1767 | } |
1768 | |
1769 | if (!rt_prio(p->prio)) |
1770 | p->sched_class = &fair_sched_class; |
1771 | |
1772 | if (p->sched_class->task_fork) |
1773 | p->sched_class->task_fork(p); |
1774 | |
1775 | /* |
1776 | * The child is not yet in the pid-hash so no cgroup attach races, |
1777 | * and the cgroup is pinned to this child due to cgroup_fork() |
1778 | * is ran before sched_fork(). |
1779 | * |
1780 | * Silence PROVE_RCU. |
1781 | */ |
1782 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
1783 | set_task_cpu(p, cpu); |
1784 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1785 | |
1786 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
1787 | if (likely(sched_info_on())) |
1788 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1789 | #endif |
1790 | #if defined(CONFIG_SMP) |
1791 | p->on_cpu = 0; |
1792 | #endif |
1793 | #ifdef CONFIG_PREEMPT_COUNT |
1794 | /* Want to start with kernel preemption disabled. */ |
1795 | task_thread_info(p)->preempt_count = 1; |
1796 | #endif |
1797 | #ifdef CONFIG_SMP |
1798 | plist_node_init(&p->pushable_tasks, MAX_PRIO); |
1799 | #endif |
1800 | |
1801 | put_cpu(); |
1802 | } |
1803 | |
1804 | /* |
1805 | * wake_up_new_task - wake up a newly created task for the first time. |
1806 | * |
1807 | * This function will do some initial scheduler statistics housekeeping |
1808 | * that must be done for every newly created context, then puts the task |
1809 | * on the runqueue and wakes it. |
1810 | */ |
1811 | void wake_up_new_task(struct task_struct *p) |
1812 | { |
1813 | unsigned long flags; |
1814 | struct rq *rq; |
1815 | |
1816 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
1817 | #ifdef CONFIG_SMP |
1818 | /* |
1819 | * Fork balancing, do it here and not earlier because: |
1820 | * - cpus_allowed can change in the fork path |
1821 | * - any previously selected cpu might disappear through hotplug |
1822 | */ |
1823 | set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0)); |
1824 | #endif |
1825 | |
1826 | rq = __task_rq_lock(p); |
1827 | activate_task(rq, p, 0); |
1828 | p->on_rq = 1; |
1829 | trace_sched_wakeup_new(p, true); |
1830 | check_preempt_curr(rq, p, WF_FORK); |
1831 | #ifdef CONFIG_SMP |
1832 | if (p->sched_class->task_woken) |
1833 | p->sched_class->task_woken(rq, p); |
1834 | #endif |
1835 | task_rq_unlock(rq, p, &flags); |
1836 | } |
1837 | |
1838 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1839 | |
1840 | /** |
1841 | * preempt_notifier_register - tell me when current is being preempted & rescheduled |
1842 | * @notifier: notifier struct to register |
1843 | */ |
1844 | void preempt_notifier_register(struct preempt_notifier *notifier) |
1845 | { |
1846 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); |
1847 | } |
1848 | EXPORT_SYMBOL_GPL(preempt_notifier_register); |
1849 | |
1850 | /** |
1851 | * preempt_notifier_unregister - no longer interested in preemption notifications |
1852 | * @notifier: notifier struct to unregister |
1853 | * |
1854 | * This is safe to call from within a preemption notifier. |
1855 | */ |
1856 | void preempt_notifier_unregister(struct preempt_notifier *notifier) |
1857 | { |
1858 | hlist_del(¬ifier->link); |
1859 | } |
1860 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); |
1861 | |
1862 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
1863 | { |
1864 | struct preempt_notifier *notifier; |
1865 | struct hlist_node *node; |
1866 | |
1867 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) |
1868 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); |
1869 | } |
1870 | |
1871 | static void |
1872 | fire_sched_out_preempt_notifiers(struct task_struct *curr, |
1873 | struct task_struct *next) |
1874 | { |
1875 | struct preempt_notifier *notifier; |
1876 | struct hlist_node *node; |
1877 | |
1878 | hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) |
1879 | notifier->ops->sched_out(notifier, next); |
1880 | } |
1881 | |
1882 | #else /* !CONFIG_PREEMPT_NOTIFIERS */ |
1883 | |
1884 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
1885 | { |
1886 | } |
1887 | |
1888 | static void |
1889 | fire_sched_out_preempt_notifiers(struct task_struct *curr, |
1890 | struct task_struct *next) |
1891 | { |
1892 | } |
1893 | |
1894 | #endif /* CONFIG_PREEMPT_NOTIFIERS */ |
1895 | |
1896 | /** |
1897 | * prepare_task_switch - prepare to switch tasks |
1898 | * @rq: the runqueue preparing to switch |
1899 | * @prev: the current task that is being switched out |
1900 | * @next: the task we are going to switch to. |
1901 | * |
1902 | * This is called with the rq lock held and interrupts off. It must |
1903 | * be paired with a subsequent finish_task_switch after the context |
1904 | * switch. |
1905 | * |
1906 | * prepare_task_switch sets up locking and calls architecture specific |
1907 | * hooks. |
1908 | */ |
1909 | static inline void |
1910 | prepare_task_switch(struct rq *rq, struct task_struct *prev, |
1911 | struct task_struct *next) |
1912 | { |
1913 | sched_info_switch(prev, next); |
1914 | perf_event_task_sched_out(prev, next); |
1915 | fire_sched_out_preempt_notifiers(prev, next); |
1916 | prepare_lock_switch(rq, next); |
1917 | prepare_arch_switch(next); |
1918 | trace_sched_switch(prev, next); |
1919 | } |
1920 | |
1921 | /** |
1922 | * finish_task_switch - clean up after a task-switch |
1923 | * @rq: runqueue associated with task-switch |
1924 | * @prev: the thread we just switched away from. |
1925 | * |
1926 | * finish_task_switch must be called after the context switch, paired |
1927 | * with a prepare_task_switch call before the context switch. |
1928 | * finish_task_switch will reconcile locking set up by prepare_task_switch, |
1929 | * and do any other architecture-specific cleanup actions. |
1930 | * |
1931 | * Note that we may have delayed dropping an mm in context_switch(). If |
1932 | * so, we finish that here outside of the runqueue lock. (Doing it |
1933 | * with the lock held can cause deadlocks; see schedule() for |
1934 | * details.) |
1935 | */ |
1936 | static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1937 | __releases(rq->lock) |
1938 | { |
1939 | struct mm_struct *mm = rq->prev_mm; |
1940 | long prev_state; |
1941 | |
1942 | rq->prev_mm = NULL; |
1943 | |
1944 | /* |
1945 | * A task struct has one reference for the use as "current". |
1946 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
1947 | * schedule one last time. The schedule call will never return, and |
1948 | * the scheduled task must drop that reference. |
1949 | * The test for TASK_DEAD must occur while the runqueue locks are |
1950 | * still held, otherwise prev could be scheduled on another cpu, die |
1951 | * there before we look at prev->state, and then the reference would |
1952 | * be dropped twice. |
1953 | * Manfred Spraul <manfred@colorfullife.com> |
1954 | */ |
1955 | prev_state = prev->state; |
1956 | finish_arch_switch(prev); |
1957 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1958 | local_irq_disable(); |
1959 | #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ |
1960 | perf_event_task_sched_in(prev, current); |
1961 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
1962 | local_irq_enable(); |
1963 | #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ |
1964 | finish_lock_switch(rq, prev); |
1965 | finish_arch_post_lock_switch(); |
1966 | |
1967 | fire_sched_in_preempt_notifiers(current); |
1968 | if (mm) |
1969 | mmdrop(mm); |
1970 | if (unlikely(prev_state == TASK_DEAD)) { |
1971 | /* |
1972 | * Remove function-return probe instances associated with this |
1973 | * task and put them back on the free list. |
1974 | */ |
1975 | kprobe_flush_task(prev); |
1976 | put_task_struct(prev); |
1977 | } |
1978 | } |
1979 | |
1980 | #ifdef CONFIG_SMP |
1981 | |
1982 | /* assumes rq->lock is held */ |
1983 | static inline void pre_schedule(struct rq *rq, struct task_struct *prev) |
1984 | { |
1985 | if (prev->sched_class->pre_schedule) |
1986 | prev->sched_class->pre_schedule(rq, prev); |
1987 | } |
1988 | |
1989 | /* rq->lock is NOT held, but preemption is disabled */ |
1990 | static inline void post_schedule(struct rq *rq) |
1991 | { |
1992 | if (rq->post_schedule) { |
1993 | unsigned long flags; |
1994 | |
1995 | raw_spin_lock_irqsave(&rq->lock, flags); |
1996 | if (rq->curr->sched_class->post_schedule) |
1997 | rq->curr->sched_class->post_schedule(rq); |
1998 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
1999 | |
2000 | rq->post_schedule = 0; |
2001 | } |
2002 | } |
2003 | |
2004 | #else |
2005 | |
2006 | static inline void pre_schedule(struct rq *rq, struct task_struct *p) |
2007 | { |
2008 | } |
2009 | |
2010 | static inline void post_schedule(struct rq *rq) |
2011 | { |
2012 | } |
2013 | |
2014 | #endif |
2015 | |
2016 | /** |
2017 | * schedule_tail - first thing a freshly forked thread must call. |
2018 | * @prev: the thread we just switched away from. |
2019 | */ |
2020 | asmlinkage void schedule_tail(struct task_struct *prev) |
2021 | __releases(rq->lock) |
2022 | { |
2023 | struct rq *rq = this_rq(); |
2024 | |
2025 | finish_task_switch(rq, prev); |
2026 | |
2027 | /* |
2028 | * FIXME: do we need to worry about rq being invalidated by the |
2029 | * task_switch? |
2030 | */ |
2031 | post_schedule(rq); |
2032 | |
2033 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW |
2034 | /* In this case, finish_task_switch does not reenable preemption */ |
2035 | preempt_enable(); |
2036 | #endif |
2037 | if (current->set_child_tid) |
2038 | put_user(task_pid_vnr(current), current->set_child_tid); |
2039 | } |
2040 | |
2041 | /* |
2042 | * context_switch - switch to the new MM and the new |
2043 | * thread's register state. |
2044 | */ |
2045 | static inline void |
2046 | context_switch(struct rq *rq, struct task_struct *prev, |
2047 | struct task_struct *next) |
2048 | { |
2049 | struct mm_struct *mm, *oldmm; |
2050 | |
2051 | prepare_task_switch(rq, prev, next); |
2052 | |
2053 | mm = next->mm; |
2054 | oldmm = prev->active_mm; |
2055 | /* |
2056 | * For paravirt, this is coupled with an exit in switch_to to |
2057 | * combine the page table reload and the switch backend into |
2058 | * one hypercall. |
2059 | */ |
2060 | arch_start_context_switch(prev); |
2061 | |
2062 | if (!mm) { |
2063 | next->active_mm = oldmm; |
2064 | atomic_inc(&oldmm->mm_count); |
2065 | enter_lazy_tlb(oldmm, next); |
2066 | } else |
2067 | switch_mm(oldmm, mm, next); |
2068 | |
2069 | if (!prev->mm) { |
2070 | prev->active_mm = NULL; |
2071 | rq->prev_mm = oldmm; |
2072 | } |
2073 | /* |
2074 | * Since the runqueue lock will be released by the next |
2075 | * task (which is an invalid locking op but in the case |
2076 | * of the scheduler it's an obvious special-case), so we |
2077 | * do an early lockdep release here: |
2078 | */ |
2079 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
2080 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
2081 | #endif |
2082 | |
2083 | /* Here we just switch the register state and the stack. */ |
2084 | switch_to(prev, next, prev); |
2085 | |
2086 | barrier(); |
2087 | /* |
2088 | * this_rq must be evaluated again because prev may have moved |
2089 | * CPUs since it called schedule(), thus the 'rq' on its stack |
2090 | * frame will be invalid. |
2091 | */ |
2092 | finish_task_switch(this_rq(), prev); |
2093 | } |
2094 | |
2095 | /* |
2096 | * nr_running, nr_uninterruptible and nr_context_switches: |
2097 | * |
2098 | * externally visible scheduler statistics: current number of runnable |
2099 | * threads, current number of uninterruptible-sleeping threads, total |
2100 | * number of context switches performed since bootup. |
2101 | */ |
2102 | unsigned long nr_running(void) |
2103 | { |
2104 | unsigned long i, sum = 0; |
2105 | |
2106 | for_each_online_cpu(i) |
2107 | sum += cpu_rq(i)->nr_running; |
2108 | |
2109 | return sum; |
2110 | } |
2111 | |
2112 | unsigned long nr_uninterruptible(void) |
2113 | { |
2114 | unsigned long i, sum = 0; |
2115 | |
2116 | for_each_possible_cpu(i) |
2117 | sum += cpu_rq(i)->nr_uninterruptible; |
2118 | |
2119 | /* |
2120 | * Since we read the counters lockless, it might be slightly |
2121 | * inaccurate. Do not allow it to go below zero though: |
2122 | */ |
2123 | if (unlikely((long)sum < 0)) |
2124 | sum = 0; |
2125 | |
2126 | return sum; |
2127 | } |
2128 | |
2129 | unsigned long long nr_context_switches(void) |
2130 | { |
2131 | int i; |
2132 | unsigned long long sum = 0; |
2133 | |
2134 | for_each_possible_cpu(i) |
2135 | sum += cpu_rq(i)->nr_switches; |
2136 | |
2137 | return sum; |
2138 | } |
2139 | |
2140 | unsigned long nr_iowait(void) |
2141 | { |
2142 | unsigned long i, sum = 0; |
2143 | |
2144 | for_each_possible_cpu(i) |
2145 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
2146 | |
2147 | return sum; |
2148 | } |
2149 | |
2150 | unsigned long nr_iowait_cpu(int cpu) |
2151 | { |
2152 | struct rq *this = cpu_rq(cpu); |
2153 | return atomic_read(&this->nr_iowait); |
2154 | } |
2155 | |
2156 | unsigned long this_cpu_load(void) |
2157 | { |
2158 | struct rq *this = this_rq(); |
2159 | return this->cpu_load[0]; |
2160 | } |
2161 | |
2162 | |
2163 | /* |
2164 | * Global load-average calculations |
2165 | * |
2166 | * We take a distributed and async approach to calculating the global load-avg |
2167 | * in order to minimize overhead. |
2168 | * |
2169 | * The global load average is an exponentially decaying average of nr_running + |
2170 | * nr_uninterruptible. |
2171 | * |
2172 | * Once every LOAD_FREQ: |
2173 | * |
2174 | * nr_active = 0; |
2175 | * for_each_possible_cpu(cpu) |
2176 | * nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible; |
2177 | * |
2178 | * avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n) |
2179 | * |
2180 | * Due to a number of reasons the above turns in the mess below: |
2181 | * |
2182 | * - for_each_possible_cpu() is prohibitively expensive on machines with |
2183 | * serious number of cpus, therefore we need to take a distributed approach |
2184 | * to calculating nr_active. |
2185 | * |
2186 | * \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0 |
2187 | * = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) } |
2188 | * |
2189 | * So assuming nr_active := 0 when we start out -- true per definition, we |
2190 | * can simply take per-cpu deltas and fold those into a global accumulate |
2191 | * to obtain the same result. See calc_load_fold_active(). |
2192 | * |
2193 | * Furthermore, in order to avoid synchronizing all per-cpu delta folding |
2194 | * across the machine, we assume 10 ticks is sufficient time for every |
2195 | * cpu to have completed this task. |
2196 | * |
2197 | * This places an upper-bound on the IRQ-off latency of the machine. Then |
2198 | * again, being late doesn't loose the delta, just wrecks the sample. |
2199 | * |
2200 | * - cpu_rq()->nr_uninterruptible isn't accurately tracked per-cpu because |
2201 | * this would add another cross-cpu cacheline miss and atomic operation |
2202 | * to the wakeup path. Instead we increment on whatever cpu the task ran |
2203 | * when it went into uninterruptible state and decrement on whatever cpu |
2204 | * did the wakeup. This means that only the sum of nr_uninterruptible over |
2205 | * all cpus yields the correct result. |
2206 | * |
2207 | * This covers the NO_HZ=n code, for extra head-aches, see the comment below. |
2208 | */ |
2209 | |
2210 | /* Variables and functions for calc_load */ |
2211 | static atomic_long_t calc_load_tasks; |
2212 | static unsigned long calc_load_update; |
2213 | unsigned long avenrun[3]; |
2214 | EXPORT_SYMBOL(avenrun); /* should be removed */ |
2215 | |
2216 | /** |
2217 | * get_avenrun - get the load average array |
2218 | * @loads: pointer to dest load array |
2219 | * @offset: offset to add |
2220 | * @shift: shift count to shift the result left |
2221 | * |
2222 | * These values are estimates at best, so no need for locking. |
2223 | */ |
2224 | void get_avenrun(unsigned long *loads, unsigned long offset, int shift) |
2225 | { |
2226 | loads[0] = (avenrun[0] + offset) << shift; |
2227 | loads[1] = (avenrun[1] + offset) << shift; |
2228 | loads[2] = (avenrun[2] + offset) << shift; |
2229 | } |
2230 | |
2231 | static long calc_load_fold_active(struct rq *this_rq) |
2232 | { |
2233 | long nr_active, delta = 0; |
2234 | |
2235 | nr_active = this_rq->nr_running; |
2236 | nr_active += (long) this_rq->nr_uninterruptible; |
2237 | |
2238 | if (nr_active != this_rq->calc_load_active) { |
2239 | delta = nr_active - this_rq->calc_load_active; |
2240 | this_rq->calc_load_active = nr_active; |
2241 | } |
2242 | |
2243 | return delta; |
2244 | } |
2245 | |
2246 | /* |
2247 | * a1 = a0 * e + a * (1 - e) |
2248 | */ |
2249 | static unsigned long |
2250 | calc_load(unsigned long load, unsigned long exp, unsigned long active) |
2251 | { |
2252 | load *= exp; |
2253 | load += active * (FIXED_1 - exp); |
2254 | load += 1UL << (FSHIFT - 1); |
2255 | return load >> FSHIFT; |
2256 | } |
2257 | |
2258 | #ifdef CONFIG_NO_HZ |
2259 | /* |
2260 | * Handle NO_HZ for the global load-average. |
2261 | * |
2262 | * Since the above described distributed algorithm to compute the global |
2263 | * load-average relies on per-cpu sampling from the tick, it is affected by |
2264 | * NO_HZ. |
2265 | * |
2266 | * The basic idea is to fold the nr_active delta into a global idle-delta upon |
2267 | * entering NO_HZ state such that we can include this as an 'extra' cpu delta |
2268 | * when we read the global state. |
2269 | * |
2270 | * Obviously reality has to ruin such a delightfully simple scheme: |
2271 | * |
2272 | * - When we go NO_HZ idle during the window, we can negate our sample |
2273 | * contribution, causing under-accounting. |
2274 | * |
2275 | * We avoid this by keeping two idle-delta counters and flipping them |
2276 | * when the window starts, thus separating old and new NO_HZ load. |
2277 | * |
2278 | * The only trick is the slight shift in index flip for read vs write. |
2279 | * |
2280 | * 0s 5s 10s 15s |
2281 | * +10 +10 +10 +10 |
2282 | * |-|-----------|-|-----------|-|-----------|-| |
2283 | * r:0 0 1 1 0 0 1 1 0 |
2284 | * w:0 1 1 0 0 1 1 0 0 |
2285 | * |
2286 | * This ensures we'll fold the old idle contribution in this window while |
2287 | * accumlating the new one. |
2288 | * |
2289 | * - When we wake up from NO_HZ idle during the window, we push up our |
2290 | * contribution, since we effectively move our sample point to a known |
2291 | * busy state. |
2292 | * |
2293 | * This is solved by pushing the window forward, and thus skipping the |
2294 | * sample, for this cpu (effectively using the idle-delta for this cpu which |
2295 | * was in effect at the time the window opened). This also solves the issue |
2296 | * of having to deal with a cpu having been in NOHZ idle for multiple |
2297 | * LOAD_FREQ intervals. |
2298 | * |
2299 | * When making the ILB scale, we should try to pull this in as well. |
2300 | */ |
2301 | static atomic_long_t calc_load_idle[2]; |
2302 | static int calc_load_idx; |
2303 | |
2304 | static inline int calc_load_write_idx(void) |
2305 | { |
2306 | int idx = calc_load_idx; |
2307 | |
2308 | /* |
2309 | * See calc_global_nohz(), if we observe the new index, we also |
2310 | * need to observe the new update time. |
2311 | */ |
2312 | smp_rmb(); |
2313 | |
2314 | /* |
2315 | * If the folding window started, make sure we start writing in the |
2316 | * next idle-delta. |
2317 | */ |
2318 | if (!time_before(jiffies, calc_load_update)) |
2319 | idx++; |
2320 | |
2321 | return idx & 1; |
2322 | } |
2323 | |
2324 | static inline int calc_load_read_idx(void) |
2325 | { |
2326 | return calc_load_idx & 1; |
2327 | } |
2328 | |
2329 | void calc_load_enter_idle(void) |
2330 | { |
2331 | struct rq *this_rq = this_rq(); |
2332 | long delta; |
2333 | |
2334 | /* |
2335 | * We're going into NOHZ mode, if there's any pending delta, fold it |
2336 | * into the pending idle delta. |
2337 | */ |
2338 | delta = calc_load_fold_active(this_rq); |
2339 | if (delta) { |
2340 | int idx = calc_load_write_idx(); |
2341 | atomic_long_add(delta, &calc_load_idle[idx]); |
2342 | } |
2343 | } |
2344 | |
2345 | void calc_load_exit_idle(void) |
2346 | { |
2347 | struct rq *this_rq = this_rq(); |
2348 | |
2349 | /* |
2350 | * If we're still before the sample window, we're done. |
2351 | */ |
2352 | if (time_before(jiffies, this_rq->calc_load_update)) |
2353 | return; |
2354 | |
2355 | /* |
2356 | * We woke inside or after the sample window, this means we're already |
2357 | * accounted through the nohz accounting, so skip the entire deal and |
2358 | * sync up for the next window. |
2359 | */ |
2360 | this_rq->calc_load_update = calc_load_update; |
2361 | if (time_before(jiffies, this_rq->calc_load_update + 10)) |
2362 | this_rq->calc_load_update += LOAD_FREQ; |
2363 | } |
2364 | |
2365 | static long calc_load_fold_idle(void) |
2366 | { |
2367 | int idx = calc_load_read_idx(); |
2368 | long delta = 0; |
2369 | |
2370 | if (atomic_long_read(&calc_load_idle[idx])) |
2371 | delta = atomic_long_xchg(&calc_load_idle[idx], 0); |
2372 | |
2373 | return delta; |
2374 | } |
2375 | |
2376 | /** |
2377 | * fixed_power_int - compute: x^n, in O(log n) time |
2378 | * |
2379 | * @x: base of the power |
2380 | * @frac_bits: fractional bits of @x |
2381 | * @n: power to raise @x to. |
2382 | * |
2383 | * By exploiting the relation between the definition of the natural power |
2384 | * function: x^n := x*x*...*x (x multiplied by itself for n times), and |
2385 | * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i, |
2386 | * (where: n_i \elem {0, 1}, the binary vector representing n), |
2387 | * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is |
2388 | * of course trivially computable in O(log_2 n), the length of our binary |
2389 | * vector. |
2390 | */ |
2391 | static unsigned long |
2392 | fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n) |
2393 | { |
2394 | unsigned long result = 1UL << frac_bits; |
2395 | |
2396 | if (n) for (;;) { |
2397 | if (n & 1) { |
2398 | result *= x; |
2399 | result += 1UL << (frac_bits - 1); |
2400 | result >>= frac_bits; |
2401 | } |
2402 | n >>= 1; |
2403 | if (!n) |
2404 | break; |
2405 | x *= x; |
2406 | x += 1UL << (frac_bits - 1); |
2407 | x >>= frac_bits; |
2408 | } |
2409 | |
2410 | return result; |
2411 | } |
2412 | |
2413 | /* |
2414 | * a1 = a0 * e + a * (1 - e) |
2415 | * |
2416 | * a2 = a1 * e + a * (1 - e) |
2417 | * = (a0 * e + a * (1 - e)) * e + a * (1 - e) |
2418 | * = a0 * e^2 + a * (1 - e) * (1 + e) |
2419 | * |
2420 | * a3 = a2 * e + a * (1 - e) |
2421 | * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e) |
2422 | * = a0 * e^3 + a * (1 - e) * (1 + e + e^2) |
2423 | * |
2424 | * ... |
2425 | * |
2426 | * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1] |
2427 | * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e) |
2428 | * = a0 * e^n + a * (1 - e^n) |
2429 | * |
2430 | * [1] application of the geometric series: |
2431 | * |
2432 | * n 1 - x^(n+1) |
2433 | * S_n := \Sum x^i = ------------- |
2434 | * i=0 1 - x |
2435 | */ |
2436 | static unsigned long |
2437 | calc_load_n(unsigned long load, unsigned long exp, |
2438 | unsigned long active, unsigned int n) |
2439 | { |
2440 | |
2441 | return calc_load(load, fixed_power_int(exp, FSHIFT, n), active); |
2442 | } |
2443 | |
2444 | /* |
2445 | * NO_HZ can leave us missing all per-cpu ticks calling |
2446 | * calc_load_account_active(), but since an idle CPU folds its delta into |
2447 | * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold |
2448 | * in the pending idle delta if our idle period crossed a load cycle boundary. |
2449 | * |
2450 | * Once we've updated the global active value, we need to apply the exponential |
2451 | * weights adjusted to the number of cycles missed. |
2452 | */ |
2453 | static void calc_global_nohz(void) |
2454 | { |
2455 | long delta, active, n; |
2456 | |
2457 | if (!time_before(jiffies, calc_load_update + 10)) { |
2458 | /* |
2459 | * Catch-up, fold however many we are behind still |
2460 | */ |
2461 | delta = jiffies - calc_load_update - 10; |
2462 | n = 1 + (delta / LOAD_FREQ); |
2463 | |
2464 | active = atomic_long_read(&calc_load_tasks); |
2465 | active = active > 0 ? active * FIXED_1 : 0; |
2466 | |
2467 | avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n); |
2468 | avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n); |
2469 | avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n); |
2470 | |
2471 | calc_load_update += n * LOAD_FREQ; |
2472 | } |
2473 | |
2474 | /* |
2475 | * Flip the idle index... |
2476 | * |
2477 | * Make sure we first write the new time then flip the index, so that |
2478 | * calc_load_write_idx() will see the new time when it reads the new |
2479 | * index, this avoids a double flip messing things up. |
2480 | */ |
2481 | smp_wmb(); |
2482 | calc_load_idx++; |
2483 | } |
2484 | #else /* !CONFIG_NO_HZ */ |
2485 | |
2486 | static inline long calc_load_fold_idle(void) { return 0; } |
2487 | static inline void calc_global_nohz(void) { } |
2488 | |
2489 | #endif /* CONFIG_NO_HZ */ |
2490 | |
2491 | /* |
2492 | * calc_load - update the avenrun load estimates 10 ticks after the |
2493 | * CPUs have updated calc_load_tasks. |
2494 | */ |
2495 | void calc_global_load(unsigned long ticks) |
2496 | { |
2497 | long active, delta; |
2498 | |
2499 | if (time_before(jiffies, calc_load_update + 10)) |
2500 | return; |
2501 | |
2502 | /* |
2503 | * Fold the 'old' idle-delta to include all NO_HZ cpus. |
2504 | */ |
2505 | delta = calc_load_fold_idle(); |
2506 | if (delta) |
2507 | atomic_long_add(delta, &calc_load_tasks); |
2508 | |
2509 | active = atomic_long_read(&calc_load_tasks); |
2510 | active = active > 0 ? active * FIXED_1 : 0; |
2511 | |
2512 | avenrun[0] = calc_load(avenrun[0], EXP_1, active); |
2513 | avenrun[1] = calc_load(avenrun[1], EXP_5, active); |
2514 | avenrun[2] = calc_load(avenrun[2], EXP_15, active); |
2515 | |
2516 | calc_load_update += LOAD_FREQ; |
2517 | |
2518 | /* |
2519 | * In case we idled for multiple LOAD_FREQ intervals, catch up in bulk. |
2520 | */ |
2521 | calc_global_nohz(); |
2522 | } |
2523 | |
2524 | /* |
2525 | * Called from update_cpu_load() to periodically update this CPU's |
2526 | * active count. |
2527 | */ |
2528 | static void calc_load_account_active(struct rq *this_rq) |
2529 | { |
2530 | long delta; |
2531 | |
2532 | if (time_before(jiffies, this_rq->calc_load_update)) |
2533 | return; |
2534 | |
2535 | delta = calc_load_fold_active(this_rq); |
2536 | if (delta) |
2537 | atomic_long_add(delta, &calc_load_tasks); |
2538 | |
2539 | this_rq->calc_load_update += LOAD_FREQ; |
2540 | } |
2541 | |
2542 | /* |
2543 | * End of global load-average stuff |
2544 | */ |
2545 | |
2546 | /* |
2547 | * The exact cpuload at various idx values, calculated at every tick would be |
2548 | * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load |
2549 | * |
2550 | * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called |
2551 | * on nth tick when cpu may be busy, then we have: |
2552 | * load = ((2^idx - 1) / 2^idx)^(n-1) * load |
2553 | * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load |
2554 | * |
2555 | * decay_load_missed() below does efficient calculation of |
2556 | * load = ((2^idx - 1) / 2^idx)^(n-1) * load |
2557 | * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load |
2558 | * |
2559 | * The calculation is approximated on a 128 point scale. |
2560 | * degrade_zero_ticks is the number of ticks after which load at any |
2561 | * particular idx is approximated to be zero. |
2562 | * degrade_factor is a precomputed table, a row for each load idx. |
2563 | * Each column corresponds to degradation factor for a power of two ticks, |
2564 | * based on 128 point scale. |
2565 | * Example: |
2566 | * row 2, col 3 (=12) says that the degradation at load idx 2 after |
2567 | * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). |
2568 | * |
2569 | * With this power of 2 load factors, we can degrade the load n times |
2570 | * by looking at 1 bits in n and doing as many mult/shift instead of |
2571 | * n mult/shifts needed by the exact degradation. |
2572 | */ |
2573 | #define DEGRADE_SHIFT 7 |
2574 | static const unsigned char |
2575 | degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; |
2576 | static const unsigned char |
2577 | degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { |
2578 | {0, 0, 0, 0, 0, 0, 0, 0}, |
2579 | {64, 32, 8, 0, 0, 0, 0, 0}, |
2580 | {96, 72, 40, 12, 1, 0, 0}, |
2581 | {112, 98, 75, 43, 15, 1, 0}, |
2582 | {120, 112, 98, 76, 45, 16, 2} }; |
2583 | |
2584 | /* |
2585 | * Update cpu_load for any missed ticks, due to tickless idle. The backlog |
2586 | * would be when CPU is idle and so we just decay the old load without |
2587 | * adding any new load. |
2588 | */ |
2589 | static unsigned long |
2590 | decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) |
2591 | { |
2592 | int j = 0; |
2593 | |
2594 | if (!missed_updates) |
2595 | return load; |
2596 | |
2597 | if (missed_updates >= degrade_zero_ticks[idx]) |
2598 | return 0; |
2599 | |
2600 | if (idx == 1) |
2601 | return load >> missed_updates; |
2602 | |
2603 | while (missed_updates) { |
2604 | if (missed_updates % 2) |
2605 | load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; |
2606 | |
2607 | missed_updates >>= 1; |
2608 | j++; |
2609 | } |
2610 | return load; |
2611 | } |
2612 | |
2613 | /* |
2614 | * Update rq->cpu_load[] statistics. This function is usually called every |
2615 | * scheduler tick (TICK_NSEC). With tickless idle this will not be called |
2616 | * every tick. We fix it up based on jiffies. |
2617 | */ |
2618 | static void __update_cpu_load(struct rq *this_rq, unsigned long this_load, |
2619 | unsigned long pending_updates) |
2620 | { |
2621 | int i, scale; |
2622 | |
2623 | this_rq->nr_load_updates++; |
2624 | |
2625 | /* Update our load: */ |
2626 | this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ |
2627 | for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { |
2628 | unsigned long old_load, new_load; |
2629 | |
2630 | /* scale is effectively 1 << i now, and >> i divides by scale */ |
2631 | |
2632 | old_load = this_rq->cpu_load[i]; |
2633 | old_load = decay_load_missed(old_load, pending_updates - 1, i); |
2634 | new_load = this_load; |
2635 | /* |
2636 | * Round up the averaging division if load is increasing. This |
2637 | * prevents us from getting stuck on 9 if the load is 10, for |
2638 | * example. |
2639 | */ |
2640 | if (new_load > old_load) |
2641 | new_load += scale - 1; |
2642 | |
2643 | this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; |
2644 | } |
2645 | |
2646 | sched_avg_update(this_rq); |
2647 | } |
2648 | |
2649 | #ifdef CONFIG_NO_HZ |
2650 | /* |
2651 | * There is no sane way to deal with nohz on smp when using jiffies because the |
2652 | * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading |
2653 | * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}. |
2654 | * |
2655 | * Therefore we cannot use the delta approach from the regular tick since that |
2656 | * would seriously skew the load calculation. However we'll make do for those |
2657 | * updates happening while idle (nohz_idle_balance) or coming out of idle |
2658 | * (tick_nohz_idle_exit). |
2659 | * |
2660 | * This means we might still be one tick off for nohz periods. |
2661 | */ |
2662 | |
2663 | /* |
2664 | * Called from nohz_idle_balance() to update the load ratings before doing the |
2665 | * idle balance. |
2666 | */ |
2667 | void update_idle_cpu_load(struct rq *this_rq) |
2668 | { |
2669 | unsigned long curr_jiffies = ACCESS_ONCE(jiffies); |
2670 | unsigned long load = this_rq->load.weight; |
2671 | unsigned long pending_updates; |
2672 | |
2673 | /* |
2674 | * bail if there's load or we're actually up-to-date. |
2675 | */ |
2676 | if (load || curr_jiffies == this_rq->last_load_update_tick) |
2677 | return; |
2678 | |
2679 | pending_updates = curr_jiffies - this_rq->last_load_update_tick; |
2680 | this_rq->last_load_update_tick = curr_jiffies; |
2681 | |
2682 | __update_cpu_load(this_rq, load, pending_updates); |
2683 | } |
2684 | |
2685 | /* |
2686 | * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed. |
2687 | */ |
2688 | void update_cpu_load_nohz(void) |
2689 | { |
2690 | struct rq *this_rq = this_rq(); |
2691 | unsigned long curr_jiffies = ACCESS_ONCE(jiffies); |
2692 | unsigned long pending_updates; |
2693 | |
2694 | if (curr_jiffies == this_rq->last_load_update_tick) |
2695 | return; |
2696 | |
2697 | raw_spin_lock(&this_rq->lock); |
2698 | pending_updates = curr_jiffies - this_rq->last_load_update_tick; |
2699 | if (pending_updates) { |
2700 | this_rq->last_load_update_tick = curr_jiffies; |
2701 | /* |
2702 | * We were idle, this means load 0, the current load might be |
2703 | * !0 due to remote wakeups and the sort. |
2704 | */ |
2705 | __update_cpu_load(this_rq, 0, pending_updates); |
2706 | } |
2707 | raw_spin_unlock(&this_rq->lock); |
2708 | } |
2709 | #endif /* CONFIG_NO_HZ */ |
2710 | |
2711 | /* |
2712 | * Called from scheduler_tick() |
2713 | */ |
2714 | static void update_cpu_load_active(struct rq *this_rq) |
2715 | { |
2716 | /* |
2717 | * See the mess around update_idle_cpu_load() / update_cpu_load_nohz(). |
2718 | */ |
2719 | this_rq->last_load_update_tick = jiffies; |
2720 | __update_cpu_load(this_rq, this_rq->load.weight, 1); |
2721 | |
2722 | calc_load_account_active(this_rq); |
2723 | } |
2724 | |
2725 | #ifdef CONFIG_SMP |
2726 | |
2727 | /* |
2728 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2729 | * this point the task has the smallest effective memory and cache footprint. |
2730 | */ |
2731 | void sched_exec(void) |
2732 | { |
2733 | struct task_struct *p = current; |
2734 | unsigned long flags; |
2735 | int dest_cpu; |
2736 | |
2737 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
2738 | dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); |
2739 | if (dest_cpu == smp_processor_id()) |
2740 | goto unlock; |
2741 | |
2742 | if (likely(cpu_active(dest_cpu))) { |
2743 | struct migration_arg arg = { p, dest_cpu }; |
2744 | |
2745 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
2746 | stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); |
2747 | return; |
2748 | } |
2749 | unlock: |
2750 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
2751 | } |
2752 | |
2753 | #endif |
2754 | |
2755 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
2756 | DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); |
2757 | |
2758 | EXPORT_PER_CPU_SYMBOL(kstat); |
2759 | EXPORT_PER_CPU_SYMBOL(kernel_cpustat); |
2760 | |
2761 | /* |
2762 | * Return any ns on the sched_clock that have not yet been accounted in |
2763 | * @p in case that task is currently running. |
2764 | * |
2765 | * Called with task_rq_lock() held on @rq. |
2766 | */ |
2767 | static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) |
2768 | { |
2769 | u64 ns = 0; |
2770 | |
2771 | if (task_current(rq, p)) { |
2772 | update_rq_clock(rq); |
2773 | ns = rq->clock_task - p->se.exec_start; |
2774 | if ((s64)ns < 0) |
2775 | ns = 0; |
2776 | } |
2777 | |
2778 | return ns; |
2779 | } |
2780 | |
2781 | unsigned long long task_delta_exec(struct task_struct *p) |
2782 | { |
2783 | unsigned long flags; |
2784 | struct rq *rq; |
2785 | u64 ns = 0; |
2786 | |
2787 | rq = task_rq_lock(p, &flags); |
2788 | ns = do_task_delta_exec(p, rq); |
2789 | task_rq_unlock(rq, p, &flags); |
2790 | |
2791 | return ns; |
2792 | } |
2793 | |
2794 | /* |
2795 | * Return accounted runtime for the task. |
2796 | * In case the task is currently running, return the runtime plus current's |
2797 | * pending runtime that have not been accounted yet. |
2798 | */ |
2799 | unsigned long long task_sched_runtime(struct task_struct *p) |
2800 | { |
2801 | unsigned long flags; |
2802 | struct rq *rq; |
2803 | u64 ns = 0; |
2804 | |
2805 | rq = task_rq_lock(p, &flags); |
2806 | ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); |
2807 | task_rq_unlock(rq, p, &flags); |
2808 | |
2809 | return ns; |
2810 | } |
2811 | |
2812 | #ifdef CONFIG_CGROUP_CPUACCT |
2813 | struct cgroup_subsys cpuacct_subsys; |
2814 | struct cpuacct root_cpuacct; |
2815 | #endif |
2816 | |
2817 | static inline void task_group_account_field(struct task_struct *p, int index, |
2818 | u64 tmp) |
2819 | { |
2820 | #ifdef CONFIG_CGROUP_CPUACCT |
2821 | struct kernel_cpustat *kcpustat; |
2822 | struct cpuacct *ca; |
2823 | #endif |
2824 | /* |
2825 | * Since all updates are sure to touch the root cgroup, we |
2826 | * get ourselves ahead and touch it first. If the root cgroup |
2827 | * is the only cgroup, then nothing else should be necessary. |
2828 | * |
2829 | */ |
2830 | __get_cpu_var(kernel_cpustat).cpustat[index] += tmp; |
2831 | |
2832 | #ifdef CONFIG_CGROUP_CPUACCT |
2833 | if (unlikely(!cpuacct_subsys.active)) |
2834 | return; |
2835 | |
2836 | rcu_read_lock(); |
2837 | ca = task_ca(p); |
2838 | while (ca && (ca != &root_cpuacct)) { |
2839 | kcpustat = this_cpu_ptr(ca->cpustat); |
2840 | kcpustat->cpustat[index] += tmp; |
2841 | ca = parent_ca(ca); |
2842 | } |
2843 | rcu_read_unlock(); |
2844 | #endif |
2845 | } |
2846 | |
2847 | |
2848 | /* |
2849 | * Account user cpu time to a process. |
2850 | * @p: the process that the cpu time gets accounted to |
2851 | * @cputime: the cpu time spent in user space since the last update |
2852 | * @cputime_scaled: cputime scaled by cpu frequency |
2853 | */ |
2854 | void account_user_time(struct task_struct *p, cputime_t cputime, |
2855 | cputime_t cputime_scaled) |
2856 | { |
2857 | int index; |
2858 | |
2859 | /* Add user time to process. */ |
2860 | p->utime += cputime; |
2861 | p->utimescaled += cputime_scaled; |
2862 | account_group_user_time(p, cputime); |
2863 | |
2864 | index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER; |
2865 | |
2866 | /* Add user time to cpustat. */ |
2867 | task_group_account_field(p, index, (__force u64) cputime); |
2868 | |
2869 | /* Account for user time used */ |
2870 | acct_update_integrals(p); |
2871 | } |
2872 | |
2873 | /* |
2874 | * Account guest cpu time to a process. |
2875 | * @p: the process that the cpu time gets accounted to |
2876 | * @cputime: the cpu time spent in virtual machine since the last update |
2877 | * @cputime_scaled: cputime scaled by cpu frequency |
2878 | */ |
2879 | static void account_guest_time(struct task_struct *p, cputime_t cputime, |
2880 | cputime_t cputime_scaled) |
2881 | { |
2882 | u64 *cpustat = kcpustat_this_cpu->cpustat; |
2883 | |
2884 | /* Add guest time to process. */ |
2885 | p->utime += cputime; |
2886 | p->utimescaled += cputime_scaled; |
2887 | account_group_user_time(p, cputime); |
2888 | p->gtime += cputime; |
2889 | |
2890 | /* Add guest time to cpustat. */ |
2891 | if (TASK_NICE(p) > 0) { |
2892 | cpustat[CPUTIME_NICE] += (__force u64) cputime; |
2893 | cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime; |
2894 | } else { |
2895 | cpustat[CPUTIME_USER] += (__force u64) cputime; |
2896 | cpustat[CPUTIME_GUEST] += (__force u64) cputime; |
2897 | } |
2898 | } |
2899 | |
2900 | /* |
2901 | * Account system cpu time to a process and desired cpustat field |
2902 | * @p: the process that the cpu time gets accounted to |
2903 | * @cputime: the cpu time spent in kernel space since the last update |
2904 | * @cputime_scaled: cputime scaled by cpu frequency |
2905 | * @target_cputime64: pointer to cpustat field that has to be updated |
2906 | */ |
2907 | static inline |
2908 | void __account_system_time(struct task_struct *p, cputime_t cputime, |
2909 | cputime_t cputime_scaled, int index) |
2910 | { |
2911 | /* Add system time to process. */ |
2912 | p->stime += cputime; |
2913 | p->stimescaled += cputime_scaled; |
2914 | account_group_system_time(p, cputime); |
2915 | |
2916 | /* Add system time to cpustat. */ |
2917 | task_group_account_field(p, index, (__force u64) cputime); |
2918 | |
2919 | /* Account for system time used */ |
2920 | acct_update_integrals(p); |
2921 | } |
2922 | |
2923 | /* |
2924 | * Account system cpu time to a process. |
2925 | * @p: the process that the cpu time gets accounted to |
2926 | * @hardirq_offset: the offset to subtract from hardirq_count() |
2927 | * @cputime: the cpu time spent in kernel space since the last update |
2928 | * @cputime_scaled: cputime scaled by cpu frequency |
2929 | */ |
2930 | void account_system_time(struct task_struct *p, int hardirq_offset, |
2931 | cputime_t cputime, cputime_t cputime_scaled) |
2932 | { |
2933 | int index; |
2934 | |
2935 | if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { |
2936 | account_guest_time(p, cputime, cputime_scaled); |
2937 | return; |
2938 | } |
2939 | |
2940 | if (hardirq_count() - hardirq_offset) |
2941 | index = CPUTIME_IRQ; |
2942 | else if (in_serving_softirq()) |
2943 | index = CPUTIME_SOFTIRQ; |
2944 | else |
2945 | index = CPUTIME_SYSTEM; |
2946 | |
2947 | __account_system_time(p, cputime, cputime_scaled, index); |
2948 | } |
2949 | |
2950 | /* |
2951 | * Account for involuntary wait time. |
2952 | * @cputime: the cpu time spent in involuntary wait |
2953 | */ |
2954 | void account_steal_time(cputime_t cputime) |
2955 | { |
2956 | u64 *cpustat = kcpustat_this_cpu->cpustat; |
2957 | |
2958 | cpustat[CPUTIME_STEAL] += (__force u64) cputime; |
2959 | } |
2960 | |
2961 | /* |
2962 | * Account for idle time. |
2963 | * @cputime: the cpu time spent in idle wait |
2964 | */ |
2965 | void account_idle_time(cputime_t cputime) |
2966 | { |
2967 | u64 *cpustat = kcpustat_this_cpu->cpustat; |
2968 | struct rq *rq = this_rq(); |
2969 | |
2970 | if (atomic_read(&rq->nr_iowait) > 0) |
2971 | cpustat[CPUTIME_IOWAIT] += (__force u64) cputime; |
2972 | else |
2973 | cpustat[CPUTIME_IDLE] += (__force u64) cputime; |
2974 | } |
2975 | |
2976 | static __always_inline bool steal_account_process_tick(void) |
2977 | { |
2978 | #ifdef CONFIG_PARAVIRT |
2979 | if (static_key_false(¶virt_steal_enabled)) { |
2980 | u64 steal, st = 0; |
2981 | |
2982 | steal = paravirt_steal_clock(smp_processor_id()); |
2983 | steal -= this_rq()->prev_steal_time; |
2984 | |
2985 | st = steal_ticks(steal); |
2986 | this_rq()->prev_steal_time += st * TICK_NSEC; |
2987 | |
2988 | account_steal_time(st); |
2989 | return st; |
2990 | } |
2991 | #endif |
2992 | return false; |
2993 | } |
2994 | |
2995 | #ifndef CONFIG_VIRT_CPU_ACCOUNTING |
2996 | |
2997 | #ifdef CONFIG_IRQ_TIME_ACCOUNTING |
2998 | /* |
2999 | * Account a tick to a process and cpustat |
3000 | * @p: the process that the cpu time gets accounted to |
3001 | * @user_tick: is the tick from userspace |
3002 | * @rq: the pointer to rq |
3003 | * |
3004 | * Tick demultiplexing follows the order |
3005 | * - pending hardirq update |
3006 | * - pending softirq update |
3007 | * - user_time |
3008 | * - idle_time |
3009 | * - system time |
3010 | * - check for guest_time |
3011 | * - else account as system_time |
3012 | * |
3013 | * Check for hardirq is done both for system and user time as there is |
3014 | * no timer going off while we are on hardirq and hence we may never get an |
3015 | * opportunity to update it solely in system time. |
3016 | * p->stime and friends are only updated on system time and not on irq |
3017 | * softirq as those do not count in task exec_runtime any more. |
3018 | */ |
3019 | static void irqtime_account_process_tick(struct task_struct *p, int user_tick, |
3020 | struct rq *rq) |
3021 | { |
3022 | cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); |
3023 | u64 *cpustat = kcpustat_this_cpu->cpustat; |
3024 | |
3025 | if (steal_account_process_tick()) |
3026 | return; |
3027 | |
3028 | if (irqtime_account_hi_update()) { |
3029 | cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy; |
3030 | } else if (irqtime_account_si_update()) { |
3031 | cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy; |
3032 | } else if (this_cpu_ksoftirqd() == p) { |
3033 | /* |
3034 | * ksoftirqd time do not get accounted in cpu_softirq_time. |
3035 | * So, we have to handle it separately here. |
3036 | * Also, p->stime needs to be updated for ksoftirqd. |
3037 | */ |
3038 | __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, |
3039 | CPUTIME_SOFTIRQ); |
3040 | } else if (user_tick) { |
3041 | account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); |
3042 | } else if (p == rq->idle) { |
3043 | account_idle_time(cputime_one_jiffy); |
3044 | } else if (p->flags & PF_VCPU) { /* System time or guest time */ |
3045 | account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled); |
3046 | } else { |
3047 | __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, |
3048 | CPUTIME_SYSTEM); |
3049 | } |
3050 | } |
3051 | |
3052 | static void irqtime_account_idle_ticks(int ticks) |
3053 | { |
3054 | int i; |
3055 | struct rq *rq = this_rq(); |
3056 | |
3057 | for (i = 0; i < ticks; i++) |
3058 | irqtime_account_process_tick(current, 0, rq); |
3059 | } |
3060 | #else /* CONFIG_IRQ_TIME_ACCOUNTING */ |
3061 | static void irqtime_account_idle_ticks(int ticks) {} |
3062 | static void irqtime_account_process_tick(struct task_struct *p, int user_tick, |
3063 | struct rq *rq) {} |
3064 | #endif /* CONFIG_IRQ_TIME_ACCOUNTING */ |
3065 | |
3066 | /* |
3067 | * Account a single tick of cpu time. |
3068 | * @p: the process that the cpu time gets accounted to |
3069 | * @user_tick: indicates if the tick is a user or a system tick |
3070 | */ |
3071 | void account_process_tick(struct task_struct *p, int user_tick) |
3072 | { |
3073 | cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); |
3074 | struct rq *rq = this_rq(); |
3075 | |
3076 | if (sched_clock_irqtime) { |
3077 | irqtime_account_process_tick(p, user_tick, rq); |
3078 | return; |
3079 | } |
3080 | |
3081 | if (steal_account_process_tick()) |
3082 | return; |
3083 | |
3084 | if (user_tick) |
3085 | account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); |
3086 | else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) |
3087 | account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, |
3088 | one_jiffy_scaled); |
3089 | else |
3090 | account_idle_time(cputime_one_jiffy); |
3091 | } |
3092 | |
3093 | /* |
3094 | * Account multiple ticks of steal time. |
3095 | * @p: the process from which the cpu time has been stolen |
3096 | * @ticks: number of stolen ticks |
3097 | */ |
3098 | void account_steal_ticks(unsigned long ticks) |
3099 | { |
3100 | account_steal_time(jiffies_to_cputime(ticks)); |
3101 | } |
3102 | |
3103 | /* |
3104 | * Account multiple ticks of idle time. |
3105 | * @ticks: number of stolen ticks |
3106 | */ |
3107 | void account_idle_ticks(unsigned long ticks) |
3108 | { |
3109 | |
3110 | if (sched_clock_irqtime) { |
3111 | irqtime_account_idle_ticks(ticks); |
3112 | return; |
3113 | } |
3114 | |
3115 | account_idle_time(jiffies_to_cputime(ticks)); |
3116 | } |
3117 | |
3118 | #endif |
3119 | |
3120 | /* |
3121 | * Use precise platform statistics if available: |
3122 | */ |
3123 | #ifdef CONFIG_VIRT_CPU_ACCOUNTING |
3124 | void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) |
3125 | { |
3126 | *ut = p->utime; |
3127 | *st = p->stime; |
3128 | } |
3129 | |
3130 | void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) |
3131 | { |
3132 | struct task_cputime cputime; |
3133 | |
3134 | thread_group_cputime(p, &cputime); |
3135 | |
3136 | *ut = cputime.utime; |
3137 | *st = cputime.stime; |
3138 | } |
3139 | #else |
3140 | |
3141 | #ifndef nsecs_to_cputime |
3142 | # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs) |
3143 | #endif |
3144 | |
3145 | void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st) |
3146 | { |
3147 | cputime_t rtime, utime = p->utime, total = utime + p->stime; |
3148 | |
3149 | /* |
3150 | * Use CFS's precise accounting: |
3151 | */ |
3152 | rtime = nsecs_to_cputime(p->se.sum_exec_runtime); |
3153 | |
3154 | if (total) { |
3155 | u64 temp = (__force u64) rtime; |
3156 | |
3157 | temp *= (__force u64) utime; |
3158 | do_div(temp, (__force u32) total); |
3159 | utime = (__force cputime_t) temp; |
3160 | } else |
3161 | utime = rtime; |
3162 | |
3163 | /* |
3164 | * Compare with previous values, to keep monotonicity: |
3165 | */ |
3166 | p->prev_utime = max(p->prev_utime, utime); |
3167 | p->prev_stime = max(p->prev_stime, rtime - p->prev_utime); |
3168 | |
3169 | *ut = p->prev_utime; |
3170 | *st = p->prev_stime; |
3171 | } |
3172 | |
3173 | /* |
3174 | * Must be called with siglock held. |
3175 | */ |
3176 | void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st) |
3177 | { |
3178 | struct signal_struct *sig = p->signal; |
3179 | struct task_cputime cputime; |
3180 | cputime_t rtime, utime, total; |
3181 | |
3182 | thread_group_cputime(p, &cputime); |
3183 | |
3184 | total = cputime.utime + cputime.stime; |
3185 | rtime = nsecs_to_cputime(cputime.sum_exec_runtime); |
3186 | |
3187 | if (total) { |
3188 | u64 temp = (__force u64) rtime; |
3189 | |
3190 | temp *= (__force u64) cputime.utime; |
3191 | do_div(temp, (__force u32) total); |
3192 | utime = (__force cputime_t) temp; |
3193 | } else |
3194 | utime = rtime; |
3195 | |
3196 | sig->prev_utime = max(sig->prev_utime, utime); |
3197 | sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime); |
3198 | |
3199 | *ut = sig->prev_utime; |
3200 | *st = sig->prev_stime; |
3201 | } |
3202 | #endif |
3203 | |
3204 | /* |
3205 | * This function gets called by the timer code, with HZ frequency. |
3206 | * We call it with interrupts disabled. |
3207 | */ |
3208 | void scheduler_tick(void) |
3209 | { |
3210 | int cpu = smp_processor_id(); |
3211 | struct rq *rq = cpu_rq(cpu); |
3212 | struct task_struct *curr = rq->curr; |
3213 | |
3214 | sched_clock_tick(); |
3215 | |
3216 | raw_spin_lock(&rq->lock); |
3217 | update_rq_clock(rq); |
3218 | update_cpu_load_active(rq); |
3219 | curr->sched_class->task_tick(rq, curr, 0); |
3220 | raw_spin_unlock(&rq->lock); |
3221 | |
3222 | perf_event_task_tick(); |
3223 | |
3224 | #ifdef CONFIG_SMP |
3225 | rq->idle_balance = idle_cpu(cpu); |
3226 | trigger_load_balance(rq, cpu); |
3227 | #endif |
3228 | } |
3229 | |
3230 | notrace unsigned long get_parent_ip(unsigned long addr) |
3231 | { |
3232 | if (in_lock_functions(addr)) { |
3233 | addr = CALLER_ADDR2; |
3234 | if (in_lock_functions(addr)) |
3235 | addr = CALLER_ADDR3; |
3236 | } |
3237 | return addr; |
3238 | } |
3239 | |
3240 | #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ |
3241 | defined(CONFIG_PREEMPT_TRACER)) |
3242 | |
3243 | void __kprobes add_preempt_count(int val) |
3244 | { |
3245 | #ifdef CONFIG_DEBUG_PREEMPT |
3246 | /* |
3247 | * Underflow? |
3248 | */ |
3249 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3250 | return; |
3251 | #endif |
3252 | preempt_count() += val; |
3253 | #ifdef CONFIG_DEBUG_PREEMPT |
3254 | /* |
3255 | * Spinlock count overflowing soon? |
3256 | */ |
3257 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3258 | PREEMPT_MASK - 10); |
3259 | #endif |
3260 | if (preempt_count() == val) |
3261 | trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); |
3262 | } |
3263 | EXPORT_SYMBOL(add_preempt_count); |
3264 | |
3265 | void __kprobes sub_preempt_count(int val) |
3266 | { |
3267 | #ifdef CONFIG_DEBUG_PREEMPT |
3268 | /* |
3269 | * Underflow? |
3270 | */ |
3271 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3272 | return; |
3273 | /* |
3274 | * Is the spinlock portion underflowing? |
3275 | */ |
3276 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3277 | !(preempt_count() & PREEMPT_MASK))) |
3278 | return; |
3279 | #endif |
3280 | |
3281 | if (preempt_count() == val) |
3282 | trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); |
3283 | preempt_count() -= val; |
3284 | } |
3285 | EXPORT_SYMBOL(sub_preempt_count); |
3286 | |
3287 | #endif |
3288 | |
3289 | /* |
3290 | * Print scheduling while atomic bug: |
3291 | */ |
3292 | static noinline void __schedule_bug(struct task_struct *prev) |
3293 | { |
3294 | if (oops_in_progress) |
3295 | return; |
3296 | |
3297 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", |
3298 | prev->comm, prev->pid, preempt_count()); |
3299 | |
3300 | debug_show_held_locks(prev); |
3301 | print_modules(); |
3302 | if (irqs_disabled()) |
3303 | print_irqtrace_events(prev); |
3304 | dump_stack(); |
3305 | add_taint(TAINT_WARN); |
3306 | } |
3307 | |
3308 | /* |
3309 | * Various schedule()-time debugging checks and statistics: |
3310 | */ |
3311 | static inline void schedule_debug(struct task_struct *prev) |
3312 | { |
3313 | /* |
3314 | * Test if we are atomic. Since do_exit() needs to call into |
3315 | * schedule() atomically, we ignore that path for now. |
3316 | * Otherwise, whine if we are scheduling when we should not be. |
3317 | */ |
3318 | if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) |
3319 | __schedule_bug(prev); |
3320 | rcu_sleep_check(); |
3321 | |
3322 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3323 | |
3324 | schedstat_inc(this_rq(), sched_count); |
3325 | } |
3326 | |
3327 | static void put_prev_task(struct rq *rq, struct task_struct *prev) |
3328 | { |
3329 | if (prev->on_rq || rq->skip_clock_update < 0) |
3330 | update_rq_clock(rq); |
3331 | prev->sched_class->put_prev_task(rq, prev); |
3332 | } |
3333 | |
3334 | /* |
3335 | * Pick up the highest-prio task: |
3336 | */ |
3337 | static inline struct task_struct * |
3338 | pick_next_task(struct rq *rq) |
3339 | { |
3340 | const struct sched_class *class; |
3341 | struct task_struct *p; |
3342 | |
3343 | /* |
3344 | * Optimization: we know that if all tasks are in |
3345 | * the fair class we can call that function directly: |
3346 | */ |
3347 | if (likely(rq->nr_running == rq->cfs.h_nr_running)) { |
3348 | p = fair_sched_class.pick_next_task(rq); |
3349 | if (likely(p)) |
3350 | return p; |
3351 | } |
3352 | |
3353 | for_each_class(class) { |
3354 | p = class->pick_next_task(rq); |
3355 | if (p) |
3356 | return p; |
3357 | } |
3358 | |
3359 | BUG(); /* the idle class will always have a runnable task */ |
3360 | } |
3361 | |
3362 | /* |
3363 | * __schedule() is the main scheduler function. |
3364 | */ |
3365 | static void __sched __schedule(void) |
3366 | { |
3367 | struct task_struct *prev, *next; |
3368 | unsigned long *switch_count; |
3369 | struct rq *rq; |
3370 | int cpu; |
3371 | |
3372 | need_resched: |
3373 | preempt_disable(); |
3374 | cpu = smp_processor_id(); |
3375 | rq = cpu_rq(cpu); |
3376 | rcu_note_context_switch(cpu); |
3377 | prev = rq->curr; |
3378 | |
3379 | schedule_debug(prev); |
3380 | |
3381 | if (sched_feat(HRTICK)) |
3382 | hrtick_clear(rq); |
3383 | |
3384 | raw_spin_lock_irq(&rq->lock); |
3385 | |
3386 | switch_count = &prev->nivcsw; |
3387 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
3388 | if (unlikely(signal_pending_state(prev->state, prev))) { |
3389 | prev->state = TASK_RUNNING; |
3390 | } else { |
3391 | deactivate_task(rq, prev, DEQUEUE_SLEEP); |
3392 | prev->on_rq = 0; |
3393 | |
3394 | /* |
3395 | * If a worker went to sleep, notify and ask workqueue |
3396 | * whether it wants to wake up a task to maintain |
3397 | * concurrency. |
3398 | */ |
3399 | if (prev->flags & PF_WQ_WORKER) { |
3400 | struct task_struct *to_wakeup; |
3401 | |
3402 | to_wakeup = wq_worker_sleeping(prev, cpu); |
3403 | if (to_wakeup) |
3404 | try_to_wake_up_local(to_wakeup); |
3405 | } |
3406 | } |
3407 | switch_count = &prev->nvcsw; |
3408 | } |
3409 | |
3410 | pre_schedule(rq, prev); |
3411 | |
3412 | if (unlikely(!rq->nr_running)) |
3413 | idle_balance(cpu, rq); |
3414 | |
3415 | put_prev_task(rq, prev); |
3416 | next = pick_next_task(rq); |
3417 | clear_tsk_need_resched(prev); |
3418 | rq->skip_clock_update = 0; |
3419 | |
3420 | if (likely(prev != next)) { |
3421 | rq->nr_switches++; |
3422 | rq->curr = next; |
3423 | ++*switch_count; |
3424 | |
3425 | context_switch(rq, prev, next); /* unlocks the rq */ |
3426 | /* |
3427 | * The context switch have flipped the stack from under us |
3428 | * and restored the local variables which were saved when |
3429 | * this task called schedule() in the past. prev == current |
3430 | * is still correct, but it can be moved to another cpu/rq. |
3431 | */ |
3432 | cpu = smp_processor_id(); |
3433 | rq = cpu_rq(cpu); |
3434 | } else |
3435 | raw_spin_unlock_irq(&rq->lock); |
3436 | |
3437 | post_schedule(rq); |
3438 | |
3439 | sched_preempt_enable_no_resched(); |
3440 | if (need_resched()) |
3441 | goto need_resched; |
3442 | } |
3443 | |
3444 | static inline void sched_submit_work(struct task_struct *tsk) |
3445 | { |
3446 | if (!tsk->state || tsk_is_pi_blocked(tsk)) |
3447 | return; |
3448 | /* |
3449 | * If we are going to sleep and we have plugged IO queued, |
3450 | * make sure to submit it to avoid deadlocks. |
3451 | */ |
3452 | if (blk_needs_flush_plug(tsk)) |
3453 | blk_schedule_flush_plug(tsk); |
3454 | } |
3455 | |
3456 | asmlinkage void __sched schedule(void) |
3457 | { |
3458 | struct task_struct *tsk = current; |
3459 | |
3460 | sched_submit_work(tsk); |
3461 | __schedule(); |
3462 | } |
3463 | EXPORT_SYMBOL(schedule); |
3464 | |
3465 | /** |
3466 | * schedule_preempt_disabled - called with preemption disabled |
3467 | * |
3468 | * Returns with preemption disabled. Note: preempt_count must be 1 |
3469 | */ |
3470 | void __sched schedule_preempt_disabled(void) |
3471 | { |
3472 | sched_preempt_enable_no_resched(); |
3473 | schedule(); |
3474 | preempt_disable(); |
3475 | } |
3476 | |
3477 | #ifdef CONFIG_MUTEX_SPIN_ON_OWNER |
3478 | |
3479 | static inline bool owner_running(struct mutex *lock, struct task_struct *owner) |
3480 | { |
3481 | if (lock->owner != owner) |
3482 | return false; |
3483 | |
3484 | /* |
3485 | * Ensure we emit the owner->on_cpu, dereference _after_ checking |
3486 | * lock->owner still matches owner, if that fails, owner might |
3487 | * point to free()d memory, if it still matches, the rcu_read_lock() |
3488 | * ensures the memory stays valid. |
3489 | */ |
3490 | barrier(); |
3491 | |
3492 | return owner->on_cpu; |
3493 | } |
3494 | |
3495 | /* |
3496 | * Look out! "owner" is an entirely speculative pointer |
3497 | * access and not reliable. |
3498 | */ |
3499 | int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) |
3500 | { |
3501 | if (!sched_feat(OWNER_SPIN)) |
3502 | return 0; |
3503 | |
3504 | rcu_read_lock(); |
3505 | while (owner_running(lock, owner)) { |
3506 | if (need_resched()) |
3507 | break; |
3508 | |
3509 | arch_mutex_cpu_relax(); |
3510 | } |
3511 | rcu_read_unlock(); |
3512 | |
3513 | /* |
3514 | * We break out the loop above on need_resched() and when the |
3515 | * owner changed, which is a sign for heavy contention. Return |
3516 | * success only when lock->owner is NULL. |
3517 | */ |
3518 | return lock->owner == NULL; |
3519 | } |
3520 | #endif |
3521 | |
3522 | #ifdef CONFIG_PREEMPT |
3523 | /* |
3524 | * this is the entry point to schedule() from in-kernel preemption |
3525 | * off of preempt_enable. Kernel preemptions off return from interrupt |
3526 | * occur there and call schedule directly. |
3527 | */ |
3528 | asmlinkage void __sched notrace preempt_schedule(void) |
3529 | { |
3530 | struct thread_info *ti = current_thread_info(); |
3531 | |
3532 | /* |
3533 | * If there is a non-zero preempt_count or interrupts are disabled, |
3534 | * we do not want to preempt the current task. Just return.. |
3535 | */ |
3536 | if (likely(ti->preempt_count || irqs_disabled())) |
3537 | return; |
3538 | |
3539 | do { |
3540 | add_preempt_count_notrace(PREEMPT_ACTIVE); |
3541 | __schedule(); |
3542 | sub_preempt_count_notrace(PREEMPT_ACTIVE); |
3543 | |
3544 | /* |
3545 | * Check again in case we missed a preemption opportunity |
3546 | * between schedule and now. |
3547 | */ |
3548 | barrier(); |
3549 | } while (need_resched()); |
3550 | } |
3551 | EXPORT_SYMBOL(preempt_schedule); |
3552 | |
3553 | /* |
3554 | * this is the entry point to schedule() from kernel preemption |
3555 | * off of irq context. |
3556 | * Note, that this is called and return with irqs disabled. This will |
3557 | * protect us against recursive calling from irq. |
3558 | */ |
3559 | asmlinkage void __sched preempt_schedule_irq(void) |
3560 | { |
3561 | struct thread_info *ti = current_thread_info(); |
3562 | |
3563 | /* Catch callers which need to be fixed */ |
3564 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
3565 | |
3566 | do { |
3567 | add_preempt_count(PREEMPT_ACTIVE); |
3568 | local_irq_enable(); |
3569 | __schedule(); |
3570 | local_irq_disable(); |
3571 | sub_preempt_count(PREEMPT_ACTIVE); |
3572 | |
3573 | /* |
3574 | * Check again in case we missed a preemption opportunity |
3575 | * between schedule and now. |
3576 | */ |
3577 | barrier(); |
3578 | } while (need_resched()); |
3579 | } |
3580 | |
3581 | #endif /* CONFIG_PREEMPT */ |
3582 | |
3583 | int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, |
3584 | void *key) |
3585 | { |
3586 | return try_to_wake_up(curr->private, mode, wake_flags); |
3587 | } |
3588 | EXPORT_SYMBOL(default_wake_function); |
3589 | |
3590 | /* |
3591 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
3592 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve |
3593 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
3594 | * |
3595 | * There are circumstances in which we can try to wake a task which has already |
3596 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
3597 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
3598 | */ |
3599 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, |
3600 | int nr_exclusive, int wake_flags, void *key) |
3601 | { |
3602 | wait_queue_t *curr, *next; |
3603 | |
3604 | list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
3605 | unsigned flags = curr->flags; |
3606 | |
3607 | if (curr->func(curr, mode, wake_flags, key) && |
3608 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
3609 | break; |
3610 | } |
3611 | } |
3612 | |
3613 | /** |
3614 | * __wake_up - wake up threads blocked on a waitqueue. |
3615 | * @q: the waitqueue |
3616 | * @mode: which threads |
3617 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
3618 | * @key: is directly passed to the wakeup function |
3619 | * |
3620 | * It may be assumed that this function implies a write memory barrier before |
3621 | * changing the task state if and only if any tasks are woken up. |
3622 | */ |
3623 | void __wake_up(wait_queue_head_t *q, unsigned int mode, |
3624 | int nr_exclusive, void *key) |
3625 | { |
3626 | unsigned long flags; |
3627 | |
3628 | spin_lock_irqsave(&q->lock, flags); |
3629 | __wake_up_common(q, mode, nr_exclusive, 0, key); |
3630 | spin_unlock_irqrestore(&q->lock, flags); |
3631 | } |
3632 | EXPORT_SYMBOL(__wake_up); |
3633 | |
3634 | /* |
3635 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. |
3636 | */ |
3637 | void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr) |
3638 | { |
3639 | __wake_up_common(q, mode, nr, 0, NULL); |
3640 | } |
3641 | EXPORT_SYMBOL_GPL(__wake_up_locked); |
3642 | |
3643 | void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) |
3644 | { |
3645 | __wake_up_common(q, mode, 1, 0, key); |
3646 | } |
3647 | EXPORT_SYMBOL_GPL(__wake_up_locked_key); |
3648 | |
3649 | /** |
3650 | * __wake_up_sync_key - wake up threads blocked on a waitqueue. |
3651 | * @q: the waitqueue |
3652 | * @mode: which threads |
3653 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
3654 | * @key: opaque value to be passed to wakeup targets |
3655 | * |
3656 | * The sync wakeup differs that the waker knows that it will schedule |
3657 | * away soon, so while the target thread will be woken up, it will not |
3658 | * be migrated to another CPU - ie. the two threads are 'synchronized' |
3659 | * with each other. This can prevent needless bouncing between CPUs. |
3660 | * |
3661 | * On UP it can prevent extra preemption. |
3662 | * |
3663 | * It may be assumed that this function implies a write memory barrier before |
3664 | * changing the task state if and only if any tasks are woken up. |
3665 | */ |
3666 | void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, |
3667 | int nr_exclusive, void *key) |
3668 | { |
3669 | unsigned long flags; |
3670 | int wake_flags = WF_SYNC; |
3671 | |
3672 | if (unlikely(!q)) |
3673 | return; |
3674 | |
3675 | if (unlikely(!nr_exclusive)) |
3676 | wake_flags = 0; |
3677 | |
3678 | spin_lock_irqsave(&q->lock, flags); |
3679 | __wake_up_common(q, mode, nr_exclusive, wake_flags, key); |
3680 | spin_unlock_irqrestore(&q->lock, flags); |
3681 | } |
3682 | EXPORT_SYMBOL_GPL(__wake_up_sync_key); |
3683 | |
3684 | /* |
3685 | * __wake_up_sync - see __wake_up_sync_key() |
3686 | */ |
3687 | void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) |
3688 | { |
3689 | __wake_up_sync_key(q, mode, nr_exclusive, NULL); |
3690 | } |
3691 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ |
3692 | |
3693 | /** |
3694 | * complete: - signals a single thread waiting on this completion |
3695 | * @x: holds the state of this particular completion |
3696 | * |
3697 | * This will wake up a single thread waiting on this completion. Threads will be |
3698 | * awakened in the same order in which they were queued. |
3699 | * |
3700 | * See also complete_all(), wait_for_completion() and related routines. |
3701 | * |
3702 | * It may be assumed that this function implies a write memory barrier before |
3703 | * changing the task state if and only if any tasks are woken up. |
3704 | */ |
3705 | void complete(struct completion *x) |
3706 | { |
3707 | unsigned long flags; |
3708 | |
3709 | spin_lock_irqsave(&x->wait.lock, flags); |
3710 | x->done++; |
3711 | __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); |
3712 | spin_unlock_irqrestore(&x->wait.lock, flags); |
3713 | } |
3714 | EXPORT_SYMBOL(complete); |
3715 | |
3716 | /** |
3717 | * complete_all: - signals all threads waiting on this completion |
3718 | * @x: holds the state of this particular completion |
3719 | * |
3720 | * This will wake up all threads waiting on this particular completion event. |
3721 | * |
3722 | * It may be assumed that this function implies a write memory barrier before |
3723 | * changing the task state if and only if any tasks are woken up. |
3724 | */ |
3725 | void complete_all(struct completion *x) |
3726 | { |
3727 | unsigned long flags; |
3728 | |
3729 | spin_lock_irqsave(&x->wait.lock, flags); |
3730 | x->done += UINT_MAX/2; |
3731 | __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); |
3732 | spin_unlock_irqrestore(&x->wait.lock, flags); |
3733 | } |
3734 | EXPORT_SYMBOL(complete_all); |
3735 | |
3736 | static inline long __sched |
3737 | do_wait_for_common(struct completion *x, long timeout, int state) |
3738 | { |
3739 | if (!x->done) { |
3740 | DECLARE_WAITQUEUE(wait, current); |
3741 | |
3742 | __add_wait_queue_tail_exclusive(&x->wait, &wait); |
3743 | do { |
3744 | if (signal_pending_state(state, current)) { |
3745 | timeout = -ERESTARTSYS; |
3746 | break; |
3747 | } |
3748 | __set_current_state(state); |
3749 | spin_unlock_irq(&x->wait.lock); |
3750 | timeout = schedule_timeout(timeout); |
3751 | spin_lock_irq(&x->wait.lock); |
3752 | } while (!x->done && timeout); |
3753 | __remove_wait_queue(&x->wait, &wait); |
3754 | if (!x->done) |
3755 | return timeout; |
3756 | } |
3757 | x->done--; |
3758 | return timeout ?: 1; |
3759 | } |
3760 | |
3761 | static long __sched |
3762 | wait_for_common(struct completion *x, long timeout, int state) |
3763 | { |
3764 | might_sleep(); |
3765 | |
3766 | spin_lock_irq(&x->wait.lock); |
3767 | timeout = do_wait_for_common(x, timeout, state); |
3768 | spin_unlock_irq(&x->wait.lock); |
3769 | return timeout; |
3770 | } |
3771 | |
3772 | /** |
3773 | * wait_for_completion: - waits for completion of a task |
3774 | * @x: holds the state of this particular completion |
3775 | * |
3776 | * This waits to be signaled for completion of a specific task. It is NOT |
3777 | * interruptible and there is no timeout. |
3778 | * |
3779 | * See also similar routines (i.e. wait_for_completion_timeout()) with timeout |
3780 | * and interrupt capability. Also see complete(). |
3781 | */ |
3782 | void __sched wait_for_completion(struct completion *x) |
3783 | { |
3784 | wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); |
3785 | } |
3786 | EXPORT_SYMBOL(wait_for_completion); |
3787 | |
3788 | /** |
3789 | * wait_for_completion_timeout: - waits for completion of a task (w/timeout) |
3790 | * @x: holds the state of this particular completion |
3791 | * @timeout: timeout value in jiffies |
3792 | * |
3793 | * This waits for either a completion of a specific task to be signaled or for a |
3794 | * specified timeout to expire. The timeout is in jiffies. It is not |
3795 | * interruptible. |
3796 | * |
3797 | * The return value is 0 if timed out, and positive (at least 1, or number of |
3798 | * jiffies left till timeout) if completed. |
3799 | */ |
3800 | unsigned long __sched |
3801 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
3802 | { |
3803 | return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
3804 | } |
3805 | EXPORT_SYMBOL(wait_for_completion_timeout); |
3806 | |
3807 | /** |
3808 | * wait_for_completion_interruptible: - waits for completion of a task (w/intr) |
3809 | * @x: holds the state of this particular completion |
3810 | * |
3811 | * This waits for completion of a specific task to be signaled. It is |
3812 | * interruptible. |
3813 | * |
3814 | * The return value is -ERESTARTSYS if interrupted, 0 if completed. |
3815 | */ |
3816 | int __sched wait_for_completion_interruptible(struct completion *x) |
3817 | { |
3818 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
3819 | if (t == -ERESTARTSYS) |
3820 | return t; |
3821 | return 0; |
3822 | } |
3823 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
3824 | |
3825 | /** |
3826 | * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) |
3827 | * @x: holds the state of this particular completion |
3828 | * @timeout: timeout value in jiffies |
3829 | * |
3830 | * This waits for either a completion of a specific task to be signaled or for a |
3831 | * specified timeout to expire. It is interruptible. The timeout is in jiffies. |
3832 | * |
3833 | * The return value is -ERESTARTSYS if interrupted, 0 if timed out, |
3834 | * positive (at least 1, or number of jiffies left till timeout) if completed. |
3835 | */ |
3836 | long __sched |
3837 | wait_for_completion_interruptible_timeout(struct completion *x, |
3838 | unsigned long timeout) |
3839 | { |
3840 | return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
3841 | } |
3842 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
3843 | |
3844 | /** |
3845 | * wait_for_completion_killable: - waits for completion of a task (killable) |
3846 | * @x: holds the state of this particular completion |
3847 | * |
3848 | * This waits to be signaled for completion of a specific task. It can be |
3849 | * interrupted by a kill signal. |
3850 | * |
3851 | * The return value is -ERESTARTSYS if interrupted, 0 if completed. |
3852 | */ |
3853 | int __sched wait_for_completion_killable(struct completion *x) |
3854 | { |
3855 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); |
3856 | if (t == -ERESTARTSYS) |
3857 | return t; |
3858 | return 0; |
3859 | } |
3860 | EXPORT_SYMBOL(wait_for_completion_killable); |
3861 | |
3862 | /** |
3863 | * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable)) |
3864 | * @x: holds the state of this particular completion |
3865 | * @timeout: timeout value in jiffies |
3866 | * |
3867 | * This waits for either a completion of a specific task to be |
3868 | * signaled or for a specified timeout to expire. It can be |
3869 | * interrupted by a kill signal. The timeout is in jiffies. |
3870 | * |
3871 | * The return value is -ERESTARTSYS if interrupted, 0 if timed out, |
3872 | * positive (at least 1, or number of jiffies left till timeout) if completed. |
3873 | */ |
3874 | long __sched |
3875 | wait_for_completion_killable_timeout(struct completion *x, |
3876 | unsigned long timeout) |
3877 | { |
3878 | return wait_for_common(x, timeout, TASK_KILLABLE); |
3879 | } |
3880 | EXPORT_SYMBOL(wait_for_completion_killable_timeout); |
3881 | |
3882 | /** |
3883 | * try_wait_for_completion - try to decrement a completion without blocking |
3884 | * @x: completion structure |
3885 | * |
3886 | * Returns: 0 if a decrement cannot be done without blocking |
3887 | * 1 if a decrement succeeded. |
3888 | * |
3889 | * If a completion is being used as a counting completion, |
3890 | * attempt to decrement the counter without blocking. This |
3891 | * enables us to avoid waiting if the resource the completion |
3892 | * is protecting is not available. |
3893 | */ |
3894 | bool try_wait_for_completion(struct completion *x) |
3895 | { |
3896 | unsigned long flags; |
3897 | int ret = 1; |
3898 | |
3899 | spin_lock_irqsave(&x->wait.lock, flags); |
3900 | if (!x->done) |
3901 | ret = 0; |
3902 | else |
3903 | x->done--; |
3904 | spin_unlock_irqrestore(&x->wait.lock, flags); |
3905 | return ret; |
3906 | } |
3907 | EXPORT_SYMBOL(try_wait_for_completion); |
3908 | |
3909 | /** |
3910 | * completion_done - Test to see if a completion has any waiters |
3911 | * @x: completion structure |
3912 | * |
3913 | * Returns: 0 if there are waiters (wait_for_completion() in progress) |
3914 | * 1 if there are no waiters. |
3915 | * |
3916 | */ |
3917 | bool completion_done(struct completion *x) |
3918 | { |
3919 | unsigned long flags; |
3920 | int ret = 1; |
3921 | |
3922 | spin_lock_irqsave(&x->wait.lock, flags); |
3923 | if (!x->done) |
3924 | ret = 0; |
3925 | spin_unlock_irqrestore(&x->wait.lock, flags); |
3926 | return ret; |
3927 | } |
3928 | EXPORT_SYMBOL(completion_done); |
3929 | |
3930 | static long __sched |
3931 | sleep_on_common(wait_queue_head_t *q, int state, long timeout) |
3932 | { |
3933 | unsigned long flags; |
3934 | wait_queue_t wait; |
3935 | |
3936 | init_waitqueue_entry(&wait, current); |
3937 | |
3938 | __set_current_state(state); |
3939 | |
3940 | spin_lock_irqsave(&q->lock, flags); |
3941 | __add_wait_queue(q, &wait); |
3942 | spin_unlock(&q->lock); |
3943 | timeout = schedule_timeout(timeout); |
3944 | spin_lock_irq(&q->lock); |
3945 | __remove_wait_queue(q, &wait); |
3946 | spin_unlock_irqrestore(&q->lock, flags); |
3947 | |
3948 | return timeout; |
3949 | } |
3950 | |
3951 | void __sched interruptible_sleep_on(wait_queue_head_t *q) |
3952 | { |
3953 | sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
3954 | } |
3955 | EXPORT_SYMBOL(interruptible_sleep_on); |
3956 | |
3957 | long __sched |
3958 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
3959 | { |
3960 | return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
3961 | } |
3962 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
3963 | |
3964 | void __sched sleep_on(wait_queue_head_t *q) |
3965 | { |
3966 | sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
3967 | } |
3968 | EXPORT_SYMBOL(sleep_on); |
3969 | |
3970 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
3971 | { |
3972 | return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
3973 | } |
3974 | EXPORT_SYMBOL(sleep_on_timeout); |
3975 | |
3976 | #ifdef CONFIG_RT_MUTEXES |
3977 | |
3978 | /* |
3979 | * rt_mutex_setprio - set the current priority of a task |
3980 | * @p: task |
3981 | * @prio: prio value (kernel-internal form) |
3982 | * |
3983 | * This function changes the 'effective' priority of a task. It does |
3984 | * not touch ->normal_prio like __setscheduler(). |
3985 | * |
3986 | * Used by the rt_mutex code to implement priority inheritance logic. |
3987 | */ |
3988 | void rt_mutex_setprio(struct task_struct *p, int prio) |
3989 | { |
3990 | int oldprio, on_rq, running; |
3991 | struct rq *rq; |
3992 | const struct sched_class *prev_class; |
3993 | |
3994 | BUG_ON(prio < 0 || prio > MAX_PRIO); |
3995 | |
3996 | rq = __task_rq_lock(p); |
3997 | |
3998 | /* |
3999 | * Idle task boosting is a nono in general. There is one |
4000 | * exception, when PREEMPT_RT and NOHZ is active: |
4001 | * |
4002 | * The idle task calls get_next_timer_interrupt() and holds |
4003 | * the timer wheel base->lock on the CPU and another CPU wants |
4004 | * to access the timer (probably to cancel it). We can safely |
4005 | * ignore the boosting request, as the idle CPU runs this code |
4006 | * with interrupts disabled and will complete the lock |
4007 | * protected section without being interrupted. So there is no |
4008 | * real need to boost. |
4009 | */ |
4010 | if (unlikely(p == rq->idle)) { |
4011 | WARN_ON(p != rq->curr); |
4012 | WARN_ON(p->pi_blocked_on); |
4013 | goto out_unlock; |
4014 | } |
4015 | |
4016 | trace_sched_pi_setprio(p, prio); |
4017 | oldprio = p->prio; |
4018 | prev_class = p->sched_class; |
4019 | on_rq = p->on_rq; |
4020 | running = task_current(rq, p); |
4021 | if (on_rq) |
4022 | dequeue_task(rq, p, 0); |
4023 | if (running) |
4024 | p->sched_class->put_prev_task(rq, p); |
4025 | |
4026 | if (rt_prio(prio)) |
4027 | p->sched_class = &rt_sched_class; |
4028 | else |
4029 | p->sched_class = &fair_sched_class; |
4030 | |
4031 | p->prio = prio; |
4032 | |
4033 | if (running) |
4034 | p->sched_class->set_curr_task(rq); |
4035 | if (on_rq) |
4036 | enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0); |
4037 | |
4038 | check_class_changed(rq, p, prev_class, oldprio); |
4039 | out_unlock: |
4040 | __task_rq_unlock(rq); |
4041 | } |
4042 | #endif |
4043 | void set_user_nice(struct task_struct *p, long nice) |
4044 | { |
4045 | int old_prio, delta, on_rq; |
4046 | unsigned long flags; |
4047 | struct rq *rq; |
4048 | |
4049 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) |
4050 | return; |
4051 | /* |
4052 | * We have to be careful, if called from sys_setpriority(), |
4053 | * the task might be in the middle of scheduling on another CPU. |
4054 | */ |
4055 | rq = task_rq_lock(p, &flags); |
4056 | /* |
4057 | * The RT priorities are set via sched_setscheduler(), but we still |
4058 | * allow the 'normal' nice value to be set - but as expected |
4059 | * it wont have any effect on scheduling until the task is |
4060 | * SCHED_FIFO/SCHED_RR: |
4061 | */ |
4062 | if (task_has_rt_policy(p)) { |
4063 | p->static_prio = NICE_TO_PRIO(nice); |
4064 | goto out_unlock; |
4065 | } |
4066 | on_rq = p->on_rq; |
4067 | if (on_rq) |
4068 | dequeue_task(rq, p, 0); |
4069 | |
4070 | p->static_prio = NICE_TO_PRIO(nice); |
4071 | set_load_weight(p); |
4072 | old_prio = p->prio; |
4073 | p->prio = effective_prio(p); |
4074 | delta = p->prio - old_prio; |
4075 | |
4076 | if (on_rq) { |
4077 | enqueue_task(rq, p, 0); |
4078 | /* |
4079 | * If the task increased its priority or is running and |
4080 | * lowered its priority, then reschedule its CPU: |
4081 | */ |
4082 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
4083 | resched_task(rq->curr); |
4084 | } |
4085 | out_unlock: |
4086 | task_rq_unlock(rq, p, &flags); |
4087 | } |
4088 | EXPORT_SYMBOL(set_user_nice); |
4089 | |
4090 | /* |
4091 | * can_nice - check if a task can reduce its nice value |
4092 | * @p: task |
4093 | * @nice: nice value |
4094 | */ |
4095 | int can_nice(const struct task_struct *p, const int nice) |
4096 | { |
4097 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
4098 | int nice_rlim = 20 - nice; |
4099 | |
4100 | return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || |
4101 | capable(CAP_SYS_NICE)); |
4102 | } |
4103 | |
4104 | #ifdef __ARCH_WANT_SYS_NICE |
4105 | |
4106 | /* |
4107 | * sys_nice - change the priority of the current process. |
4108 | * @increment: priority increment |
4109 | * |
4110 | * sys_setpriority is a more generic, but much slower function that |
4111 | * does similar things. |
4112 | */ |
4113 | SYSCALL_DEFINE1(nice, int, increment) |
4114 | { |
4115 | long nice, retval; |
4116 | |
4117 | /* |
4118 | * Setpriority might change our priority at the same moment. |
4119 | * We don't have to worry. Conceptually one call occurs first |
4120 | * and we have a single winner. |
4121 | */ |
4122 | if (increment < -40) |
4123 | increment = -40; |
4124 | if (increment > 40) |
4125 | increment = 40; |
4126 | |
4127 | nice = TASK_NICE(current) + increment; |
4128 | if (nice < -20) |
4129 | nice = -20; |
4130 | if (nice > 19) |
4131 | nice = 19; |
4132 | |
4133 | if (increment < 0 && !can_nice(current, nice)) |
4134 | return -EPERM; |
4135 | |
4136 | retval = security_task_setnice(current, nice); |
4137 | if (retval) |
4138 | return retval; |
4139 | |
4140 | set_user_nice(current, nice); |
4141 | return 0; |
4142 | } |
4143 | |
4144 | #endif |
4145 | |
4146 | /** |
4147 | * task_prio - return the priority value of a given task. |
4148 | * @p: the task in question. |
4149 | * |
4150 | * This is the priority value as seen by users in /proc. |
4151 | * RT tasks are offset by -200. Normal tasks are centered |
4152 | * around 0, value goes from -16 to +15. |
4153 | */ |
4154 | int task_prio(const struct task_struct *p) |
4155 | { |
4156 | return p->prio - MAX_RT_PRIO; |
4157 | } |
4158 | |
4159 | /** |
4160 | * task_nice - return the nice value of a given task. |
4161 | * @p: the task in question. |
4162 | */ |
4163 | int task_nice(const struct task_struct *p) |
4164 | { |
4165 | return TASK_NICE(p); |
4166 | } |
4167 | EXPORT_SYMBOL(task_nice); |
4168 | |
4169 | /** |
4170 | * idle_cpu - is a given cpu idle currently? |
4171 | * @cpu: the processor in question. |
4172 | */ |
4173 | int idle_cpu(int cpu) |
4174 | { |
4175 | struct rq *rq = cpu_rq(cpu); |
4176 | |
4177 | if (rq->curr != rq->idle) |
4178 | return 0; |
4179 | |
4180 | if (rq->nr_running) |
4181 | return 0; |
4182 | |
4183 | #ifdef CONFIG_SMP |
4184 | if (!llist_empty(&rq->wake_list)) |
4185 | return 0; |
4186 | #endif |
4187 | |
4188 | return 1; |
4189 | } |
4190 | |
4191 | /** |
4192 | * idle_task - return the idle task for a given cpu. |
4193 | * @cpu: the processor in question. |
4194 | */ |
4195 | struct task_struct *idle_task(int cpu) |
4196 | { |
4197 | return cpu_rq(cpu)->idle; |
4198 | } |
4199 | |
4200 | /** |
4201 | * find_process_by_pid - find a process with a matching PID value. |
4202 | * @pid: the pid in question. |
4203 | */ |
4204 | static struct task_struct *find_process_by_pid(pid_t pid) |
4205 | { |
4206 | return pid ? find_task_by_vpid(pid) : current; |
4207 | } |
4208 | |
4209 | /* Actually do priority change: must hold rq lock. */ |
4210 | static void |
4211 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) |
4212 | { |
4213 | p->policy = policy; |
4214 | p->rt_priority = prio; |
4215 | p->normal_prio = normal_prio(p); |
4216 | /* we are holding p->pi_lock already */ |
4217 | p->prio = rt_mutex_getprio(p); |
4218 | if (rt_prio(p->prio)) |
4219 | p->sched_class = &rt_sched_class; |
4220 | else |
4221 | p->sched_class = &fair_sched_class; |
4222 | set_load_weight(p); |
4223 | } |
4224 | |
4225 | /* |
4226 | * check the target process has a UID that matches the current process's |
4227 | */ |
4228 | static bool check_same_owner(struct task_struct *p) |
4229 | { |
4230 | const struct cred *cred = current_cred(), *pcred; |
4231 | bool match; |
4232 | |
4233 | rcu_read_lock(); |
4234 | pcred = __task_cred(p); |
4235 | match = (uid_eq(cred->euid, pcred->euid) || |
4236 | uid_eq(cred->euid, pcred->uid)); |
4237 | rcu_read_unlock(); |
4238 | return match; |
4239 | } |
4240 | |
4241 | static int __sched_setscheduler(struct task_struct *p, int policy, |
4242 | const struct sched_param *param, bool user) |
4243 | { |
4244 | int retval, oldprio, oldpolicy = -1, on_rq, running; |
4245 | unsigned long flags; |
4246 | const struct sched_class *prev_class; |
4247 | struct rq *rq; |
4248 | int reset_on_fork; |
4249 | |
4250 | /* may grab non-irq protected spin_locks */ |
4251 | BUG_ON(in_interrupt()); |
4252 | recheck: |
4253 | /* double check policy once rq lock held */ |
4254 | if (policy < 0) { |
4255 | reset_on_fork = p->sched_reset_on_fork; |
4256 | policy = oldpolicy = p->policy; |
4257 | } else { |
4258 | reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); |
4259 | policy &= ~SCHED_RESET_ON_FORK; |
4260 | |
4261 | if (policy != SCHED_FIFO && policy != SCHED_RR && |
4262 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4263 | policy != SCHED_IDLE) |
4264 | return -EINVAL; |
4265 | } |
4266 | |
4267 | /* |
4268 | * Valid priorities for SCHED_FIFO and SCHED_RR are |
4269 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4270 | * SCHED_BATCH and SCHED_IDLE is 0. |
4271 | */ |
4272 | if (param->sched_priority < 0 || |
4273 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
4274 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
4275 | return -EINVAL; |
4276 | if (rt_policy(policy) != (param->sched_priority != 0)) |
4277 | return -EINVAL; |
4278 | |
4279 | /* |
4280 | * Allow unprivileged RT tasks to decrease priority: |
4281 | */ |
4282 | if (user && !capable(CAP_SYS_NICE)) { |
4283 | if (rt_policy(policy)) { |
4284 | unsigned long rlim_rtprio = |
4285 | task_rlimit(p, RLIMIT_RTPRIO); |
4286 | |
4287 | /* can't set/change the rt policy */ |
4288 | if (policy != p->policy && !rlim_rtprio) |
4289 | return -EPERM; |
4290 | |
4291 | /* can't increase priority */ |
4292 | if (param->sched_priority > p->rt_priority && |
4293 | param->sched_priority > rlim_rtprio) |
4294 | return -EPERM; |
4295 | } |
4296 | |
4297 | /* |
4298 | * Treat SCHED_IDLE as nice 20. Only allow a switch to |
4299 | * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. |
4300 | */ |
4301 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { |
4302 | if (!can_nice(p, TASK_NICE(p))) |
4303 | return -EPERM; |
4304 | } |
4305 | |
4306 | /* can't change other user's priorities */ |
4307 | if (!check_same_owner(p)) |
4308 | return -EPERM; |
4309 | |
4310 | /* Normal users shall not reset the sched_reset_on_fork flag */ |
4311 | if (p->sched_reset_on_fork && !reset_on_fork) |
4312 | return -EPERM; |
4313 | } |
4314 | |
4315 | if (user) { |
4316 | retval = security_task_setscheduler(p); |
4317 | if (retval) |
4318 | return retval; |
4319 | } |
4320 | |
4321 | /* |
4322 | * make sure no PI-waiters arrive (or leave) while we are |
4323 | * changing the priority of the task: |
4324 | * |
4325 | * To be able to change p->policy safely, the appropriate |
4326 | * runqueue lock must be held. |
4327 | */ |
4328 | rq = task_rq_lock(p, &flags); |
4329 | |
4330 | /* |
4331 | * Changing the policy of the stop threads its a very bad idea |
4332 | */ |
4333 | if (p == rq->stop) { |
4334 | task_rq_unlock(rq, p, &flags); |
4335 | return -EINVAL; |
4336 | } |
4337 | |
4338 | /* |
4339 | * If not changing anything there's no need to proceed further: |
4340 | */ |
4341 | if (unlikely(policy == p->policy && (!rt_policy(policy) || |
4342 | param->sched_priority == p->rt_priority))) { |
4343 | |
4344 | __task_rq_unlock(rq); |
4345 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
4346 | return 0; |
4347 | } |
4348 | |
4349 | #ifdef CONFIG_RT_GROUP_SCHED |
4350 | if (user) { |
4351 | /* |
4352 | * Do not allow realtime tasks into groups that have no runtime |
4353 | * assigned. |
4354 | */ |
4355 | if (rt_bandwidth_enabled() && rt_policy(policy) && |
4356 | task_group(p)->rt_bandwidth.rt_runtime == 0 && |
4357 | !task_group_is_autogroup(task_group(p))) { |
4358 | task_rq_unlock(rq, p, &flags); |
4359 | return -EPERM; |
4360 | } |
4361 | } |
4362 | #endif |
4363 | |
4364 | /* recheck policy now with rq lock held */ |
4365 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { |
4366 | policy = oldpolicy = -1; |
4367 | task_rq_unlock(rq, p, &flags); |
4368 | goto recheck; |
4369 | } |
4370 | on_rq = p->on_rq; |
4371 | running = task_current(rq, p); |
4372 | if (on_rq) |
4373 | dequeue_task(rq, p, 0); |
4374 | if (running) |
4375 | p->sched_class->put_prev_task(rq, p); |
4376 | |
4377 | p->sched_reset_on_fork = reset_on_fork; |
4378 | |
4379 | oldprio = p->prio; |
4380 | prev_class = p->sched_class; |
4381 | __setscheduler(rq, p, policy, param->sched_priority); |
4382 | |
4383 | if (running) |
4384 | p->sched_class->set_curr_task(rq); |
4385 | if (on_rq) |
4386 | enqueue_task(rq, p, 0); |
4387 | |
4388 | check_class_changed(rq, p, prev_class, oldprio); |
4389 | task_rq_unlock(rq, p, &flags); |
4390 | |
4391 | rt_mutex_adjust_pi(p); |
4392 | |
4393 | return 0; |
4394 | } |
4395 | |
4396 | /** |
4397 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
4398 | * @p: the task in question. |
4399 | * @policy: new policy. |
4400 | * @param: structure containing the new RT priority. |
4401 | * |
4402 | * NOTE that the task may be already dead. |
4403 | */ |
4404 | int sched_setscheduler(struct task_struct *p, int policy, |
4405 | const struct sched_param *param) |
4406 | { |
4407 | return __sched_setscheduler(p, policy, param, true); |
4408 | } |
4409 | EXPORT_SYMBOL_GPL(sched_setscheduler); |
4410 | |
4411 | /** |
4412 | * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. |
4413 | * @p: the task in question. |
4414 | * @policy: new policy. |
4415 | * @param: structure containing the new RT priority. |
4416 | * |
4417 | * Just like sched_setscheduler, only don't bother checking if the |
4418 | * current context has permission. For example, this is needed in |
4419 | * stop_machine(): we create temporary high priority worker threads, |
4420 | * but our caller might not have that capability. |
4421 | */ |
4422 | int sched_setscheduler_nocheck(struct task_struct *p, int policy, |
4423 | const struct sched_param *param) |
4424 | { |
4425 | return __sched_setscheduler(p, policy, param, false); |
4426 | } |
4427 | |
4428 | static int |
4429 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) |
4430 | { |
4431 | struct sched_param lparam; |
4432 | struct task_struct *p; |
4433 | int retval; |
4434 | |
4435 | if (!param || pid < 0) |
4436 | return -EINVAL; |
4437 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) |
4438 | return -EFAULT; |
4439 | |
4440 | rcu_read_lock(); |
4441 | retval = -ESRCH; |
4442 | p = find_process_by_pid(pid); |
4443 | if (p != NULL) |
4444 | retval = sched_setscheduler(p, policy, &lparam); |
4445 | rcu_read_unlock(); |
4446 | |
4447 | return retval; |
4448 | } |
4449 | |
4450 | /** |
4451 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority |
4452 | * @pid: the pid in question. |
4453 | * @policy: new policy. |
4454 | * @param: structure containing the new RT priority. |
4455 | */ |
4456 | SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, |
4457 | struct sched_param __user *, param) |
4458 | { |
4459 | /* negative values for policy are not valid */ |
4460 | if (policy < 0) |
4461 | return -EINVAL; |
4462 | |
4463 | return do_sched_setscheduler(pid, policy, param); |
4464 | } |
4465 | |
4466 | /** |
4467 | * sys_sched_setparam - set/change the RT priority of a thread |
4468 | * @pid: the pid in question. |
4469 | * @param: structure containing the new RT priority. |
4470 | */ |
4471 | SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) |
4472 | { |
4473 | return do_sched_setscheduler(pid, -1, param); |
4474 | } |
4475 | |
4476 | /** |
4477 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread |
4478 | * @pid: the pid in question. |
4479 | */ |
4480 | SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) |
4481 | { |
4482 | struct task_struct *p; |
4483 | int retval; |
4484 | |
4485 | if (pid < 0) |
4486 | return -EINVAL; |
4487 | |
4488 | retval = -ESRCH; |
4489 | rcu_read_lock(); |
4490 | p = find_process_by_pid(pid); |
4491 | if (p) { |
4492 | retval = security_task_getscheduler(p); |
4493 | if (!retval) |
4494 | retval = p->policy |
4495 | | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); |
4496 | } |
4497 | rcu_read_unlock(); |
4498 | return retval; |
4499 | } |
4500 | |
4501 | /** |
4502 | * sys_sched_getparam - get the RT priority of a thread |
4503 | * @pid: the pid in question. |
4504 | * @param: structure containing the RT priority. |
4505 | */ |
4506 | SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) |
4507 | { |
4508 | struct sched_param lp; |
4509 | struct task_struct *p; |
4510 | int retval; |
4511 | |
4512 | if (!param || pid < 0) |
4513 | return -EINVAL; |
4514 | |
4515 | rcu_read_lock(); |
4516 | p = find_process_by_pid(pid); |
4517 | retval = -ESRCH; |
4518 | if (!p) |
4519 | goto out_unlock; |
4520 | |
4521 | retval = security_task_getscheduler(p); |
4522 | if (retval) |
4523 | goto out_unlock; |
4524 | |
4525 | lp.sched_priority = p->rt_priority; |
4526 | rcu_read_unlock(); |
4527 | |
4528 | /* |
4529 | * This one might sleep, we cannot do it with a spinlock held ... |
4530 | */ |
4531 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; |
4532 | |
4533 | return retval; |
4534 | |
4535 | out_unlock: |
4536 | rcu_read_unlock(); |
4537 | return retval; |
4538 | } |
4539 | |
4540 | long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) |
4541 | { |
4542 | cpumask_var_t cpus_allowed, new_mask; |
4543 | struct task_struct *p; |
4544 | int retval; |
4545 | |
4546 | get_online_cpus(); |
4547 | rcu_read_lock(); |
4548 | |
4549 | p = find_process_by_pid(pid); |
4550 | if (!p) { |
4551 | rcu_read_unlock(); |
4552 | put_online_cpus(); |
4553 | return -ESRCH; |
4554 | } |
4555 | |
4556 | /* Prevent p going away */ |
4557 | get_task_struct(p); |
4558 | rcu_read_unlock(); |
4559 | |
4560 | if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { |
4561 | retval = -ENOMEM; |
4562 | goto out_put_task; |
4563 | } |
4564 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { |
4565 | retval = -ENOMEM; |
4566 | goto out_free_cpus_allowed; |
4567 | } |
4568 | retval = -EPERM; |
4569 | if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE)) |
4570 | goto out_unlock; |
4571 | |
4572 | retval = security_task_setscheduler(p); |
4573 | if (retval) |
4574 | goto out_unlock; |
4575 | |
4576 | cpuset_cpus_allowed(p, cpus_allowed); |
4577 | cpumask_and(new_mask, in_mask, cpus_allowed); |
4578 | again: |
4579 | retval = set_cpus_allowed_ptr(p, new_mask); |
4580 | |
4581 | if (!retval) { |
4582 | cpuset_cpus_allowed(p, cpus_allowed); |
4583 | if (!cpumask_subset(new_mask, cpus_allowed)) { |
4584 | /* |
4585 | * We must have raced with a concurrent cpuset |
4586 | * update. Just reset the cpus_allowed to the |
4587 | * cpuset's cpus_allowed |
4588 | */ |
4589 | cpumask_copy(new_mask, cpus_allowed); |
4590 | goto again; |
4591 | } |
4592 | } |
4593 | out_unlock: |
4594 | free_cpumask_var(new_mask); |
4595 | out_free_cpus_allowed: |
4596 | free_cpumask_var(cpus_allowed); |
4597 | out_put_task: |
4598 | put_task_struct(p); |
4599 | put_online_cpus(); |
4600 | return retval; |
4601 | } |
4602 | |
4603 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, |
4604 | struct cpumask *new_mask) |
4605 | { |
4606 | if (len < cpumask_size()) |
4607 | cpumask_clear(new_mask); |
4608 | else if (len > cpumask_size()) |
4609 | len = cpumask_size(); |
4610 | |
4611 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
4612 | } |
4613 | |
4614 | /** |
4615 | * sys_sched_setaffinity - set the cpu affinity of a process |
4616 | * @pid: pid of the process |
4617 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
4618 | * @user_mask_ptr: user-space pointer to the new cpu mask |
4619 | */ |
4620 | SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, |
4621 | unsigned long __user *, user_mask_ptr) |
4622 | { |
4623 | cpumask_var_t new_mask; |
4624 | int retval; |
4625 | |
4626 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) |
4627 | return -ENOMEM; |
4628 | |
4629 | retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); |
4630 | if (retval == 0) |
4631 | retval = sched_setaffinity(pid, new_mask); |
4632 | free_cpumask_var(new_mask); |
4633 | return retval; |
4634 | } |
4635 | |
4636 | long sched_getaffinity(pid_t pid, struct cpumask *mask) |
4637 | { |
4638 | struct task_struct *p; |
4639 | unsigned long flags; |
4640 | int retval; |
4641 | |
4642 | get_online_cpus(); |
4643 | rcu_read_lock(); |
4644 | |
4645 | retval = -ESRCH; |
4646 | p = find_process_by_pid(pid); |
4647 | if (!p) |
4648 | goto out_unlock; |
4649 | |
4650 | retval = security_task_getscheduler(p); |
4651 | if (retval) |
4652 | goto out_unlock; |
4653 | |
4654 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
4655 | cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); |
4656 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
4657 | |
4658 | out_unlock: |
4659 | rcu_read_unlock(); |
4660 | put_online_cpus(); |
4661 | |
4662 | return retval; |
4663 | } |
4664 | |
4665 | /** |
4666 | * sys_sched_getaffinity - get the cpu affinity of a process |
4667 | * @pid: pid of the process |
4668 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
4669 | * @user_mask_ptr: user-space pointer to hold the current cpu mask |
4670 | */ |
4671 | SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, |
4672 | unsigned long __user *, user_mask_ptr) |
4673 | { |
4674 | int ret; |
4675 | cpumask_var_t mask; |
4676 | |
4677 | if ((len * BITS_PER_BYTE) < nr_cpu_ids) |
4678 | return -EINVAL; |
4679 | if (len & (sizeof(unsigned long)-1)) |
4680 | return -EINVAL; |
4681 | |
4682 | if (!alloc_cpumask_var(&mask, GFP_KERNEL)) |
4683 | return -ENOMEM; |
4684 | |
4685 | ret = sched_getaffinity(pid, mask); |
4686 | if (ret == 0) { |
4687 | size_t retlen = min_t(size_t, len, cpumask_size()); |
4688 | |
4689 | if (copy_to_user(user_mask_ptr, mask, retlen)) |
4690 | ret = -EFAULT; |
4691 | else |
4692 | ret = retlen; |
4693 | } |
4694 | free_cpumask_var(mask); |
4695 | |
4696 | return ret; |
4697 | } |
4698 | |
4699 | /** |
4700 | * sys_sched_yield - yield the current processor to other threads. |
4701 | * |
4702 | * This function yields the current CPU to other tasks. If there are no |
4703 | * other threads running on this CPU then this function will return. |
4704 | */ |
4705 | SYSCALL_DEFINE0(sched_yield) |
4706 | { |
4707 | struct rq *rq = this_rq_lock(); |
4708 | |
4709 | schedstat_inc(rq, yld_count); |
4710 | current->sched_class->yield_task(rq); |
4711 | |
4712 | /* |
4713 | * Since we are going to call schedule() anyway, there's |
4714 | * no need to preempt or enable interrupts: |
4715 | */ |
4716 | __release(rq->lock); |
4717 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
4718 | do_raw_spin_unlock(&rq->lock); |
4719 | sched_preempt_enable_no_resched(); |
4720 | |
4721 | schedule(); |
4722 | |
4723 | return 0; |
4724 | } |
4725 | |
4726 | static inline int should_resched(void) |
4727 | { |
4728 | return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); |
4729 | } |
4730 | |
4731 | static void __cond_resched(void) |
4732 | { |
4733 | add_preempt_count(PREEMPT_ACTIVE); |
4734 | __schedule(); |
4735 | sub_preempt_count(PREEMPT_ACTIVE); |
4736 | } |
4737 | |
4738 | int __sched _cond_resched(void) |
4739 | { |
4740 | if (should_resched()) { |
4741 | __cond_resched(); |
4742 | return 1; |
4743 | } |
4744 | return 0; |
4745 | } |
4746 | EXPORT_SYMBOL(_cond_resched); |
4747 | |
4748 | /* |
4749 | * __cond_resched_lock() - if a reschedule is pending, drop the given lock, |
4750 | * call schedule, and on return reacquire the lock. |
4751 | * |
4752 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
4753 | * operations here to prevent schedule() from being called twice (once via |
4754 | * spin_unlock(), once by hand). |
4755 | */ |
4756 | int __cond_resched_lock(spinlock_t *lock) |
4757 | { |
4758 | int resched = should_resched(); |
4759 | int ret = 0; |
4760 | |
4761 | lockdep_assert_held(lock); |
4762 | |
4763 | if (spin_needbreak(lock) || resched) { |
4764 | spin_unlock(lock); |
4765 | if (resched) |
4766 | __cond_resched(); |
4767 | else |
4768 | cpu_relax(); |
4769 | ret = 1; |
4770 | spin_lock(lock); |
4771 | } |
4772 | return ret; |
4773 | } |
4774 | EXPORT_SYMBOL(__cond_resched_lock); |
4775 | |
4776 | int __sched __cond_resched_softirq(void) |
4777 | { |
4778 | BUG_ON(!in_softirq()); |
4779 | |
4780 | if (should_resched()) { |
4781 | local_bh_enable(); |
4782 | __cond_resched(); |
4783 | local_bh_disable(); |
4784 | return 1; |
4785 | } |
4786 | return 0; |
4787 | } |
4788 | EXPORT_SYMBOL(__cond_resched_softirq); |
4789 | |
4790 | /** |
4791 | * yield - yield the current processor to other threads. |
4792 | * |
4793 | * Do not ever use this function, there's a 99% chance you're doing it wrong. |
4794 | * |
4795 | * The scheduler is at all times free to pick the calling task as the most |
4796 | * eligible task to run, if removing the yield() call from your code breaks |
4797 | * it, its already broken. |
4798 | * |
4799 | * Typical broken usage is: |
4800 | * |
4801 | * while (!event) |
4802 | * yield(); |
4803 | * |
4804 | * where one assumes that yield() will let 'the other' process run that will |
4805 | * make event true. If the current task is a SCHED_FIFO task that will never |
4806 | * happen. Never use yield() as a progress guarantee!! |
4807 | * |
4808 | * If you want to use yield() to wait for something, use wait_event(). |
4809 | * If you want to use yield() to be 'nice' for others, use cond_resched(). |
4810 | * If you still want to use yield(), do not! |
4811 | */ |
4812 | void __sched yield(void) |
4813 | { |
4814 | set_current_state(TASK_RUNNING); |
4815 | sys_sched_yield(); |
4816 | } |
4817 | EXPORT_SYMBOL(yield); |
4818 | |
4819 | /** |
4820 | * yield_to - yield the current processor to another thread in |
4821 | * your thread group, or accelerate that thread toward the |
4822 | * processor it's on. |
4823 | * @p: target task |
4824 | * @preempt: whether task preemption is allowed or not |
4825 | * |
4826 | * It's the caller's job to ensure that the target task struct |
4827 | * can't go away on us before we can do any checks. |
4828 | * |
4829 | * Returns true if we indeed boosted the target task. |
4830 | */ |
4831 | bool __sched yield_to(struct task_struct *p, bool preempt) |
4832 | { |
4833 | struct task_struct *curr = current; |
4834 | struct rq *rq, *p_rq; |
4835 | unsigned long flags; |
4836 | bool yielded = 0; |
4837 | |
4838 | local_irq_save(flags); |
4839 | rq = this_rq(); |
4840 | |
4841 | again: |
4842 | p_rq = task_rq(p); |
4843 | double_rq_lock(rq, p_rq); |
4844 | while (task_rq(p) != p_rq) { |
4845 | double_rq_unlock(rq, p_rq); |
4846 | goto again; |
4847 | } |
4848 | |
4849 | if (!curr->sched_class->yield_to_task) |
4850 | goto out; |
4851 | |
4852 | if (curr->sched_class != p->sched_class) |
4853 | goto out; |
4854 | |
4855 | if (task_running(p_rq, p) || p->state) |
4856 | goto out; |
4857 | |
4858 | yielded = curr->sched_class->yield_to_task(rq, p, preempt); |
4859 | if (yielded) { |
4860 | schedstat_inc(rq, yld_count); |
4861 | /* |
4862 | * Make p's CPU reschedule; pick_next_entity takes care of |
4863 | * fairness. |
4864 | */ |
4865 | if (preempt && rq != p_rq) |
4866 | resched_task(p_rq->curr); |
4867 | } else { |
4868 | /* |
4869 | * We might have set it in task_yield_fair(), but are |
4870 | * not going to schedule(), so don't want to skip |
4871 | * the next update. |
4872 | */ |
4873 | rq->skip_clock_update = 0; |
4874 | } |
4875 | |
4876 | out: |
4877 | double_rq_unlock(rq, p_rq); |
4878 | local_irq_restore(flags); |
4879 | |
4880 | if (yielded) |
4881 | schedule(); |
4882 | |
4883 | return yielded; |
4884 | } |
4885 | EXPORT_SYMBOL_GPL(yield_to); |
4886 | |
4887 | /* |
4888 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
4889 | * that process accounting knows that this is a task in IO wait state. |
4890 | */ |
4891 | void __sched io_schedule(void) |
4892 | { |
4893 | struct rq *rq = raw_rq(); |
4894 | |
4895 | delayacct_blkio_start(); |
4896 | atomic_inc(&rq->nr_iowait); |
4897 | blk_flush_plug(current); |
4898 | current->in_iowait = 1; |
4899 | schedule(); |
4900 | current->in_iowait = 0; |
4901 | atomic_dec(&rq->nr_iowait); |
4902 | delayacct_blkio_end(); |
4903 | } |
4904 | EXPORT_SYMBOL(io_schedule); |
4905 | |
4906 | long __sched io_schedule_timeout(long timeout) |
4907 | { |
4908 | struct rq *rq = raw_rq(); |
4909 | long ret; |
4910 | |
4911 | delayacct_blkio_start(); |
4912 | atomic_inc(&rq->nr_iowait); |
4913 | blk_flush_plug(current); |
4914 | current->in_iowait = 1; |
4915 | ret = schedule_timeout(timeout); |
4916 | current->in_iowait = 0; |
4917 | atomic_dec(&rq->nr_iowait); |
4918 | delayacct_blkio_end(); |
4919 | return ret; |
4920 | } |
4921 | |
4922 | /** |
4923 | * sys_sched_get_priority_max - return maximum RT priority. |
4924 | * @policy: scheduling class. |
4925 | * |
4926 | * this syscall returns the maximum rt_priority that can be used |
4927 | * by a given scheduling class. |
4928 | */ |
4929 | SYSCALL_DEFINE1(sched_get_priority_max, int, policy) |
4930 | { |
4931 | int ret = -EINVAL; |
4932 | |
4933 | switch (policy) { |
4934 | case SCHED_FIFO: |
4935 | case SCHED_RR: |
4936 | ret = MAX_USER_RT_PRIO-1; |
4937 | break; |
4938 | case SCHED_NORMAL: |
4939 | case SCHED_BATCH: |
4940 | case SCHED_IDLE: |
4941 | ret = 0; |
4942 | break; |
4943 | } |
4944 | return ret; |
4945 | } |
4946 | |
4947 | /** |
4948 | * sys_sched_get_priority_min - return minimum RT priority. |
4949 | * @policy: scheduling class. |
4950 | * |
4951 | * this syscall returns the minimum rt_priority that can be used |
4952 | * by a given scheduling class. |
4953 | */ |
4954 | SYSCALL_DEFINE1(sched_get_priority_min, int, policy) |
4955 | { |
4956 | int ret = -EINVAL; |
4957 | |
4958 | switch (policy) { |
4959 | case SCHED_FIFO: |
4960 | case SCHED_RR: |
4961 | ret = 1; |
4962 | break; |
4963 | case SCHED_NORMAL: |
4964 | case SCHED_BATCH: |
4965 | case SCHED_IDLE: |
4966 | ret = 0; |
4967 | } |
4968 | return ret; |
4969 | } |
4970 | |
4971 | /** |
4972 | * sys_sched_rr_get_interval - return the default timeslice of a process. |
4973 | * @pid: pid of the process. |
4974 | * @interval: userspace pointer to the timeslice value. |
4975 | * |
4976 | * this syscall writes the default timeslice value of a given process |
4977 | * into the user-space timespec buffer. A value of '0' means infinity. |
4978 | */ |
4979 | SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, |
4980 | struct timespec __user *, interval) |
4981 | { |
4982 | struct task_struct *p; |
4983 | unsigned int time_slice; |
4984 | unsigned long flags; |
4985 | struct rq *rq; |
4986 | int retval; |
4987 | struct timespec t; |
4988 | |
4989 | if (pid < 0) |
4990 | return -EINVAL; |
4991 | |
4992 | retval = -ESRCH; |
4993 | rcu_read_lock(); |
4994 | p = find_process_by_pid(pid); |
4995 | if (!p) |
4996 | goto out_unlock; |
4997 | |
4998 | retval = security_task_getscheduler(p); |
4999 | if (retval) |
5000 | goto out_unlock; |
5001 | |
5002 | rq = task_rq_lock(p, &flags); |
5003 | time_slice = p->sched_class->get_rr_interval(rq, p); |
5004 | task_rq_unlock(rq, p, &flags); |
5005 | |
5006 | rcu_read_unlock(); |
5007 | jiffies_to_timespec(time_slice, &t); |
5008 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
5009 | return retval; |
5010 | |
5011 | out_unlock: |
5012 | rcu_read_unlock(); |
5013 | return retval; |
5014 | } |
5015 | |
5016 | static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; |
5017 | |
5018 | void sched_show_task(struct task_struct *p) |
5019 | { |
5020 | unsigned long free = 0; |
5021 | unsigned state; |
5022 | |
5023 | state = p->state ? __ffs(p->state) + 1 : 0; |
5024 | printk(KERN_INFO "%-15.15s %c", p->comm, |
5025 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
5026 | #if BITS_PER_LONG == 32 |
5027 | if (state == TASK_RUNNING) |
5028 | printk(KERN_CONT " running "); |
5029 | else |
5030 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
5031 | #else |
5032 | if (state == TASK_RUNNING) |
5033 | printk(KERN_CONT " running task "); |
5034 | else |
5035 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
5036 | #endif |
5037 | #ifdef CONFIG_DEBUG_STACK_USAGE |
5038 | free = stack_not_used(p); |
5039 | #endif |
5040 | printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, |
5041 | task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)), |
5042 | (unsigned long)task_thread_info(p)->flags); |
5043 | |
5044 | show_stack(p, NULL); |
5045 | } |
5046 | |
5047 | void show_state_filter(unsigned long state_filter) |
5048 | { |
5049 | struct task_struct *g, *p; |
5050 | |
5051 | #if BITS_PER_LONG == 32 |
5052 | printk(KERN_INFO |
5053 | " task PC stack pid father\n"); |
5054 | #else |
5055 | printk(KERN_INFO |
5056 | " task PC stack pid father\n"); |
5057 | #endif |
5058 | rcu_read_lock(); |
5059 | do_each_thread(g, p) { |
5060 | /* |
5061 | * reset the NMI-timeout, listing all files on a slow |
5062 | * console might take a lot of time: |
5063 | */ |
5064 | touch_nmi_watchdog(); |
5065 | if (!state_filter || (p->state & state_filter)) |
5066 | sched_show_task(p); |
5067 | } while_each_thread(g, p); |
5068 | |
5069 | touch_all_softlockup_watchdogs(); |
5070 | |
5071 | #ifdef CONFIG_SCHED_DEBUG |
5072 | sysrq_sched_debug_show(); |
5073 | #endif |
5074 | rcu_read_unlock(); |
5075 | /* |
5076 | * Only show locks if all tasks are dumped: |
5077 | */ |
5078 | if (!state_filter) |
5079 | debug_show_all_locks(); |
5080 | } |
5081 | |
5082 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
5083 | { |
5084 | idle->sched_class = &idle_sched_class; |
5085 | } |
5086 | |
5087 | /** |
5088 | * init_idle - set up an idle thread for a given CPU |
5089 | * @idle: task in question |
5090 | * @cpu: cpu the idle task belongs to |
5091 | * |
5092 | * NOTE: this function does not set the idle thread's NEED_RESCHED |
5093 | * flag, to make booting more robust. |
5094 | */ |
5095 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
5096 | { |
5097 | struct rq *rq = cpu_rq(cpu); |
5098 | unsigned long flags; |
5099 | |
5100 | raw_spin_lock_irqsave(&rq->lock, flags); |
5101 | |
5102 | __sched_fork(idle); |
5103 | idle->state = TASK_RUNNING; |
5104 | idle->se.exec_start = sched_clock(); |
5105 | |
5106 | do_set_cpus_allowed(idle, cpumask_of(cpu)); |
5107 | /* |
5108 | * We're having a chicken and egg problem, even though we are |
5109 | * holding rq->lock, the cpu isn't yet set to this cpu so the |
5110 | * lockdep check in task_group() will fail. |
5111 | * |
5112 | * Similar case to sched_fork(). / Alternatively we could |
5113 | * use task_rq_lock() here and obtain the other rq->lock. |
5114 | * |
5115 | * Silence PROVE_RCU |
5116 | */ |
5117 | rcu_read_lock(); |
5118 | __set_task_cpu(idle, cpu); |
5119 | rcu_read_unlock(); |
5120 | |
5121 | rq->curr = rq->idle = idle; |
5122 | #if defined(CONFIG_SMP) |
5123 | idle->on_cpu = 1; |
5124 | #endif |
5125 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5126 | |
5127 | /* Set the preempt count _outside_ the spinlocks! */ |
5128 | task_thread_info(idle)->preempt_count = 0; |
5129 | |
5130 | /* |
5131 | * The idle tasks have their own, simple scheduling class: |
5132 | */ |
5133 | idle->sched_class = &idle_sched_class; |
5134 | ftrace_graph_init_idle_task(idle, cpu); |
5135 | #if defined(CONFIG_SMP) |
5136 | sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); |
5137 | #endif |
5138 | } |
5139 | |
5140 | #ifdef CONFIG_SMP |
5141 | void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) |
5142 | { |
5143 | if (p->sched_class && p->sched_class->set_cpus_allowed) |
5144 | p->sched_class->set_cpus_allowed(p, new_mask); |
5145 | |
5146 | cpumask_copy(&p->cpus_allowed, new_mask); |
5147 | p->nr_cpus_allowed = cpumask_weight(new_mask); |
5148 | } |
5149 | |
5150 | /* |
5151 | * This is how migration works: |
5152 | * |
5153 | * 1) we invoke migration_cpu_stop() on the target CPU using |
5154 | * stop_one_cpu(). |
5155 | * 2) stopper starts to run (implicitly forcing the migrated thread |
5156 | * off the CPU) |
5157 | * 3) it checks whether the migrated task is still in the wrong runqueue. |
5158 | * 4) if it's in the wrong runqueue then the migration thread removes |
5159 | * it and puts it into the right queue. |
5160 | * 5) stopper completes and stop_one_cpu() returns and the migration |
5161 | * is done. |
5162 | */ |
5163 | |
5164 | /* |
5165 | * Change a given task's CPU affinity. Migrate the thread to a |
5166 | * proper CPU and schedule it away if the CPU it's executing on |
5167 | * is removed from the allowed bitmask. |
5168 | * |
5169 | * NOTE: the caller must have a valid reference to the task, the |
5170 | * task must not exit() & deallocate itself prematurely. The |
5171 | * call is not atomic; no spinlocks may be held. |
5172 | */ |
5173 | int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) |
5174 | { |
5175 | unsigned long flags; |
5176 | struct rq *rq; |
5177 | unsigned int dest_cpu; |
5178 | int ret = 0; |
5179 | |
5180 | rq = task_rq_lock(p, &flags); |
5181 | |
5182 | if (cpumask_equal(&p->cpus_allowed, new_mask)) |
5183 | goto out; |
5184 | |
5185 | if (!cpumask_intersects(new_mask, cpu_active_mask)) { |
5186 | ret = -EINVAL; |
5187 | goto out; |
5188 | } |
5189 | |
5190 | if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) { |
5191 | ret = -EINVAL; |
5192 | goto out; |
5193 | } |
5194 | |
5195 | do_set_cpus_allowed(p, new_mask); |
5196 | |
5197 | /* Can the task run on the task's current CPU? If so, we're done */ |
5198 | if (cpumask_test_cpu(task_cpu(p), new_mask)) |
5199 | goto out; |
5200 | |
5201 | dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); |
5202 | if (p->on_rq) { |
5203 | struct migration_arg arg = { p, dest_cpu }; |
5204 | /* Need help from migration thread: drop lock and wait. */ |
5205 | task_rq_unlock(rq, p, &flags); |
5206 | stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); |
5207 | tlb_migrate_finish(p->mm); |
5208 | return 0; |
5209 | } |
5210 | out: |
5211 | task_rq_unlock(rq, p, &flags); |
5212 | |
5213 | return ret; |
5214 | } |
5215 | EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); |
5216 | |
5217 | /* |
5218 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
5219 | * this because either it can't run here any more (set_cpus_allowed() |
5220 | * away from this CPU, or CPU going down), or because we're |
5221 | * attempting to rebalance this task on exec (sched_exec). |
5222 | * |
5223 | * So we race with normal scheduler movements, but that's OK, as long |
5224 | * as the task is no longer on this CPU. |
5225 | * |
5226 | * Returns non-zero if task was successfully migrated. |
5227 | */ |
5228 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
5229 | { |
5230 | struct rq *rq_dest, *rq_src; |
5231 | int ret = 0; |
5232 | |
5233 | if (unlikely(!cpu_active(dest_cpu))) |
5234 | return ret; |
5235 | |
5236 | rq_src = cpu_rq(src_cpu); |
5237 | rq_dest = cpu_rq(dest_cpu); |
5238 | |
5239 | raw_spin_lock(&p->pi_lock); |
5240 | double_rq_lock(rq_src, rq_dest); |
5241 | /* Already moved. */ |
5242 | if (task_cpu(p) != src_cpu) |
5243 | goto done; |
5244 | /* Affinity changed (again). */ |
5245 | if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) |
5246 | goto fail; |
5247 | |
5248 | /* |
5249 | * If we're not on a rq, the next wake-up will ensure we're |
5250 | * placed properly. |
5251 | */ |
5252 | if (p->on_rq) { |
5253 | dequeue_task(rq_src, p, 0); |
5254 | set_task_cpu(p, dest_cpu); |
5255 | enqueue_task(rq_dest, p, 0); |
5256 | check_preempt_curr(rq_dest, p, 0); |
5257 | } |
5258 | done: |
5259 | ret = 1; |
5260 | fail: |
5261 | double_rq_unlock(rq_src, rq_dest); |
5262 | raw_spin_unlock(&p->pi_lock); |
5263 | return ret; |
5264 | } |
5265 | |
5266 | /* |
5267 | * migration_cpu_stop - this will be executed by a highprio stopper thread |
5268 | * and performs thread migration by bumping thread off CPU then |
5269 | * 'pushing' onto another runqueue. |
5270 | */ |
5271 | static int migration_cpu_stop(void *data) |
5272 | { |
5273 | struct migration_arg *arg = data; |
5274 | |
5275 | /* |
5276 | * The original target cpu might have gone down and we might |
5277 | * be on another cpu but it doesn't matter. |
5278 | */ |
5279 | local_irq_disable(); |
5280 | __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); |
5281 | local_irq_enable(); |
5282 | return 0; |
5283 | } |
5284 | |
5285 | #ifdef CONFIG_HOTPLUG_CPU |
5286 | |
5287 | /* |
5288 | * Ensures that the idle task is using init_mm right before its cpu goes |
5289 | * offline. |
5290 | */ |
5291 | void idle_task_exit(void) |
5292 | { |
5293 | struct mm_struct *mm = current->active_mm; |
5294 | |
5295 | BUG_ON(cpu_online(smp_processor_id())); |
5296 | |
5297 | if (mm != &init_mm) |
5298 | switch_mm(mm, &init_mm, current); |
5299 | mmdrop(mm); |
5300 | } |
5301 | |
5302 | /* |
5303 | * While a dead CPU has no uninterruptible tasks queued at this point, |
5304 | * it might still have a nonzero ->nr_uninterruptible counter, because |
5305 | * for performance reasons the counter is not stricly tracking tasks to |
5306 | * their home CPUs. So we just add the counter to another CPU's counter, |
5307 | * to keep the global sum constant after CPU-down: |
5308 | */ |
5309 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
5310 | { |
5311 | struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask)); |
5312 | |
5313 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; |
5314 | rq_src->nr_uninterruptible = 0; |
5315 | } |
5316 | |
5317 | /* |
5318 | * remove the tasks which were accounted by rq from calc_load_tasks. |
5319 | */ |
5320 | static void calc_global_load_remove(struct rq *rq) |
5321 | { |
5322 | atomic_long_sub(rq->calc_load_active, &calc_load_tasks); |
5323 | rq->calc_load_active = 0; |
5324 | } |
5325 | |
5326 | /* |
5327 | * Migrate all tasks from the rq, sleeping tasks will be migrated by |
5328 | * try_to_wake_up()->select_task_rq(). |
5329 | * |
5330 | * Called with rq->lock held even though we'er in stop_machine() and |
5331 | * there's no concurrency possible, we hold the required locks anyway |
5332 | * because of lock validation efforts. |
5333 | */ |
5334 | static void migrate_tasks(unsigned int dead_cpu) |
5335 | { |
5336 | struct rq *rq = cpu_rq(dead_cpu); |
5337 | struct task_struct *next, *stop = rq->stop; |
5338 | int dest_cpu; |
5339 | |
5340 | /* |
5341 | * Fudge the rq selection such that the below task selection loop |
5342 | * doesn't get stuck on the currently eligible stop task. |
5343 | * |
5344 | * We're currently inside stop_machine() and the rq is either stuck |
5345 | * in the stop_machine_cpu_stop() loop, or we're executing this code, |
5346 | * either way we should never end up calling schedule() until we're |
5347 | * done here. |
5348 | */ |
5349 | rq->stop = NULL; |
5350 | |
5351 | /* Ensure any throttled groups are reachable by pick_next_task */ |
5352 | unthrottle_offline_cfs_rqs(rq); |
5353 | |
5354 | for ( ; ; ) { |
5355 | /* |
5356 | * There's this thread running, bail when that's the only |
5357 | * remaining thread. |
5358 | */ |
5359 | if (rq->nr_running == 1) |
5360 | break; |
5361 | |
5362 | next = pick_next_task(rq); |
5363 | BUG_ON(!next); |
5364 | next->sched_class->put_prev_task(rq, next); |
5365 | |
5366 | /* Find suitable destination for @next, with force if needed. */ |
5367 | dest_cpu = select_fallback_rq(dead_cpu, next); |
5368 | raw_spin_unlock(&rq->lock); |
5369 | |
5370 | __migrate_task(next, dead_cpu, dest_cpu); |
5371 | |
5372 | raw_spin_lock(&rq->lock); |
5373 | } |
5374 | |
5375 | rq->stop = stop; |
5376 | } |
5377 | |
5378 | #endif /* CONFIG_HOTPLUG_CPU */ |
5379 | |
5380 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
5381 | |
5382 | static struct ctl_table sd_ctl_dir[] = { |
5383 | { |
5384 | .procname = "sched_domain", |
5385 | .mode = 0555, |
5386 | }, |
5387 | {} |
5388 | }; |
5389 | |
5390 | static struct ctl_table sd_ctl_root[] = { |
5391 | { |
5392 | .procname = "kernel", |
5393 | .mode = 0555, |
5394 | .child = sd_ctl_dir, |
5395 | }, |
5396 | {} |
5397 | }; |
5398 | |
5399 | static struct ctl_table *sd_alloc_ctl_entry(int n) |
5400 | { |
5401 | struct ctl_table *entry = |
5402 | kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
5403 | |
5404 | return entry; |
5405 | } |
5406 | |
5407 | static void sd_free_ctl_entry(struct ctl_table **tablep) |
5408 | { |
5409 | struct ctl_table *entry; |
5410 | |
5411 | /* |
5412 | * In the intermediate directories, both the child directory and |
5413 | * procname are dynamically allocated and could fail but the mode |
5414 | * will always be set. In the lowest directory the names are |
5415 | * static strings and all have proc handlers. |
5416 | */ |
5417 | for (entry = *tablep; entry->mode; entry++) { |
5418 | if (entry->child) |
5419 | sd_free_ctl_entry(&entry->child); |
5420 | if (entry->proc_handler == NULL) |
5421 | kfree(entry->procname); |
5422 | } |
5423 | |
5424 | kfree(*tablep); |
5425 | *tablep = NULL; |
5426 | } |
5427 | |
5428 | static void |
5429 | set_table_entry(struct ctl_table *entry, |
5430 | const char *procname, void *data, int maxlen, |
5431 | umode_t mode, proc_handler *proc_handler) |
5432 | { |
5433 | entry->procname = procname; |
5434 | entry->data = data; |
5435 | entry->maxlen = maxlen; |
5436 | entry->mode = mode; |
5437 | entry->proc_handler = proc_handler; |
5438 | } |
5439 | |
5440 | static struct ctl_table * |
5441 | sd_alloc_ctl_domain_table(struct sched_domain *sd) |
5442 | { |
5443 | struct ctl_table *table = sd_alloc_ctl_entry(13); |
5444 | |
5445 | if (table == NULL) |
5446 | return NULL; |
5447 | |
5448 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
5449 | sizeof(long), 0644, proc_doulongvec_minmax); |
5450 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
5451 | sizeof(long), 0644, proc_doulongvec_minmax); |
5452 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
5453 | sizeof(int), 0644, proc_dointvec_minmax); |
5454 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
5455 | sizeof(int), 0644, proc_dointvec_minmax); |
5456 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
5457 | sizeof(int), 0644, proc_dointvec_minmax); |
5458 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
5459 | sizeof(int), 0644, proc_dointvec_minmax); |
5460 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
5461 | sizeof(int), 0644, proc_dointvec_minmax); |
5462 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
5463 | sizeof(int), 0644, proc_dointvec_minmax); |
5464 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
5465 | sizeof(int), 0644, proc_dointvec_minmax); |
5466 | set_table_entry(&table[9], "cache_nice_tries", |
5467 | &sd->cache_nice_tries, |
5468 | sizeof(int), 0644, proc_dointvec_minmax); |
5469 | set_table_entry(&table[10], "flags", &sd->flags, |
5470 | sizeof(int), 0644, proc_dointvec_minmax); |
5471 | set_table_entry(&table[11], "name", sd->name, |
5472 | CORENAME_MAX_SIZE, 0444, proc_dostring); |
5473 | /* &table[12] is terminator */ |
5474 | |
5475 | return table; |
5476 | } |
5477 | |
5478 | static ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
5479 | { |
5480 | struct ctl_table *entry, *table; |
5481 | struct sched_domain *sd; |
5482 | int domain_num = 0, i; |
5483 | char buf[32]; |
5484 | |
5485 | for_each_domain(cpu, sd) |
5486 | domain_num++; |
5487 | entry = table = sd_alloc_ctl_entry(domain_num + 1); |
5488 | if (table == NULL) |
5489 | return NULL; |
5490 | |
5491 | i = 0; |
5492 | for_each_domain(cpu, sd) { |
5493 | snprintf(buf, 32, "domain%d", i); |
5494 | entry->procname = kstrdup(buf, GFP_KERNEL); |
5495 | entry->mode = 0555; |
5496 | entry->child = sd_alloc_ctl_domain_table(sd); |
5497 | entry++; |
5498 | i++; |
5499 | } |
5500 | return table; |
5501 | } |
5502 | |
5503 | static struct ctl_table_header *sd_sysctl_header; |
5504 | static void register_sched_domain_sysctl(void) |
5505 | { |
5506 | int i, cpu_num = num_possible_cpus(); |
5507 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); |
5508 | char buf[32]; |
5509 | |
5510 | WARN_ON(sd_ctl_dir[0].child); |
5511 | sd_ctl_dir[0].child = entry; |
5512 | |
5513 | if (entry == NULL) |
5514 | return; |
5515 | |
5516 | for_each_possible_cpu(i) { |
5517 | snprintf(buf, 32, "cpu%d", i); |
5518 | entry->procname = kstrdup(buf, GFP_KERNEL); |
5519 | entry->mode = 0555; |
5520 | entry->child = sd_alloc_ctl_cpu_table(i); |
5521 | entry++; |
5522 | } |
5523 | |
5524 | WARN_ON(sd_sysctl_header); |
5525 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
5526 | } |
5527 | |
5528 | /* may be called multiple times per register */ |
5529 | static void unregister_sched_domain_sysctl(void) |
5530 | { |
5531 | if (sd_sysctl_header) |
5532 | unregister_sysctl_table(sd_sysctl_header); |
5533 | sd_sysctl_header = NULL; |
5534 | if (sd_ctl_dir[0].child) |
5535 | sd_free_ctl_entry(&sd_ctl_dir[0].child); |
5536 | } |
5537 | #else |
5538 | static void register_sched_domain_sysctl(void) |
5539 | { |
5540 | } |
5541 | static void unregister_sched_domain_sysctl(void) |
5542 | { |
5543 | } |
5544 | #endif |
5545 | |
5546 | static void set_rq_online(struct rq *rq) |
5547 | { |
5548 | if (!rq->online) { |
5549 | const struct sched_class *class; |
5550 | |
5551 | cpumask_set_cpu(rq->cpu, rq->rd->online); |
5552 | rq->online = 1; |
5553 | |
5554 | for_each_class(class) { |
5555 | if (class->rq_online) |
5556 | class->rq_online(rq); |
5557 | } |
5558 | } |
5559 | } |
5560 | |
5561 | static void set_rq_offline(struct rq *rq) |
5562 | { |
5563 | if (rq->online) { |
5564 | const struct sched_class *class; |
5565 | |
5566 | for_each_class(class) { |
5567 | if (class->rq_offline) |
5568 | class->rq_offline(rq); |
5569 | } |
5570 | |
5571 | cpumask_clear_cpu(rq->cpu, rq->rd->online); |
5572 | rq->online = 0; |
5573 | } |
5574 | } |
5575 | |
5576 | /* |
5577 | * migration_call - callback that gets triggered when a CPU is added. |
5578 | * Here we can start up the necessary migration thread for the new CPU. |
5579 | */ |
5580 | static int __cpuinit |
5581 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) |
5582 | { |
5583 | int cpu = (long)hcpu; |
5584 | unsigned long flags; |
5585 | struct rq *rq = cpu_rq(cpu); |
5586 | |
5587 | switch (action & ~CPU_TASKS_FROZEN) { |
5588 | |
5589 | case CPU_UP_PREPARE: |
5590 | rq->calc_load_update = calc_load_update; |
5591 | break; |
5592 | |
5593 | case CPU_ONLINE: |
5594 | /* Update our root-domain */ |
5595 | raw_spin_lock_irqsave(&rq->lock, flags); |
5596 | if (rq->rd) { |
5597 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
5598 | |
5599 | set_rq_online(rq); |
5600 | } |
5601 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5602 | break; |
5603 | |
5604 | #ifdef CONFIG_HOTPLUG_CPU |
5605 | case CPU_DYING: |
5606 | sched_ttwu_pending(); |
5607 | /* Update our root-domain */ |
5608 | raw_spin_lock_irqsave(&rq->lock, flags); |
5609 | if (rq->rd) { |
5610 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
5611 | set_rq_offline(rq); |
5612 | } |
5613 | migrate_tasks(cpu); |
5614 | BUG_ON(rq->nr_running != 1); /* the migration thread */ |
5615 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5616 | |
5617 | migrate_nr_uninterruptible(rq); |
5618 | calc_global_load_remove(rq); |
5619 | break; |
5620 | #endif |
5621 | } |
5622 | |
5623 | update_max_interval(); |
5624 | |
5625 | return NOTIFY_OK; |
5626 | } |
5627 | |
5628 | /* |
5629 | * Register at high priority so that task migration (migrate_all_tasks) |
5630 | * happens before everything else. This has to be lower priority than |
5631 | * the notifier in the perf_event subsystem, though. |
5632 | */ |
5633 | static struct notifier_block __cpuinitdata migration_notifier = { |
5634 | .notifier_call = migration_call, |
5635 | .priority = CPU_PRI_MIGRATION, |
5636 | }; |
5637 | |
5638 | static int __cpuinit sched_cpu_active(struct notifier_block *nfb, |
5639 | unsigned long action, void *hcpu) |
5640 | { |
5641 | switch (action & ~CPU_TASKS_FROZEN) { |
5642 | case CPU_STARTING: |
5643 | case CPU_DOWN_FAILED: |
5644 | set_cpu_active((long)hcpu, true); |
5645 | return NOTIFY_OK; |
5646 | default: |
5647 | return NOTIFY_DONE; |
5648 | } |
5649 | } |
5650 | |
5651 | static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb, |
5652 | unsigned long action, void *hcpu) |
5653 | { |
5654 | switch (action & ~CPU_TASKS_FROZEN) { |
5655 | case CPU_DOWN_PREPARE: |
5656 | set_cpu_active((long)hcpu, false); |
5657 | return NOTIFY_OK; |
5658 | default: |
5659 | return NOTIFY_DONE; |
5660 | } |
5661 | } |
5662 | |
5663 | static int __init migration_init(void) |
5664 | { |
5665 | void *cpu = (void *)(long)smp_processor_id(); |
5666 | int err; |
5667 | |
5668 | /* Initialize migration for the boot CPU */ |
5669 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5670 | BUG_ON(err == NOTIFY_BAD); |
5671 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5672 | register_cpu_notifier(&migration_notifier); |
5673 | |
5674 | /* Register cpu active notifiers */ |
5675 | cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); |
5676 | cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); |
5677 | |
5678 | return 0; |
5679 | } |
5680 | early_initcall(migration_init); |
5681 | #endif |
5682 | |
5683 | #ifdef CONFIG_SMP |
5684 | |
5685 | static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ |
5686 | |
5687 | #ifdef CONFIG_SCHED_DEBUG |
5688 | |
5689 | static __read_mostly int sched_debug_enabled; |
5690 | |
5691 | static int __init sched_debug_setup(char *str) |
5692 | { |
5693 | sched_debug_enabled = 1; |
5694 | |
5695 | return 0; |
5696 | } |
5697 | early_param("sched_debug", sched_debug_setup); |
5698 | |
5699 | static inline bool sched_debug(void) |
5700 | { |
5701 | return sched_debug_enabled; |
5702 | } |
5703 | |
5704 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, |
5705 | struct cpumask *groupmask) |
5706 | { |
5707 | struct sched_group *group = sd->groups; |
5708 | char str[256]; |
5709 | |
5710 | cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); |
5711 | cpumask_clear(groupmask); |
5712 | |
5713 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); |
5714 | |
5715 | if (!(sd->flags & SD_LOAD_BALANCE)) { |
5716 | printk("does not load-balance\n"); |
5717 | if (sd->parent) |
5718 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
5719 | " has parent"); |
5720 | return -1; |
5721 | } |
5722 | |
5723 | printk(KERN_CONT "span %s level %s\n", str, sd->name); |
5724 | |
5725 | if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
5726 | printk(KERN_ERR "ERROR: domain->span does not contain " |
5727 | "CPU%d\n", cpu); |
5728 | } |
5729 | if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { |
5730 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
5731 | " CPU%d\n", cpu); |
5732 | } |
5733 | |
5734 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
5735 | do { |
5736 | if (!group) { |
5737 | printk("\n"); |
5738 | printk(KERN_ERR "ERROR: group is NULL\n"); |
5739 | break; |
5740 | } |
5741 | |
5742 | /* |
5743 | * Even though we initialize ->power to something semi-sane, |
5744 | * we leave power_orig unset. This allows us to detect if |
5745 | * domain iteration is still funny without causing /0 traps. |
5746 | */ |
5747 | if (!group->sgp->power_orig) { |
5748 | printk(KERN_CONT "\n"); |
5749 | printk(KERN_ERR "ERROR: domain->cpu_power not " |
5750 | "set\n"); |
5751 | break; |
5752 | } |
5753 | |
5754 | if (!cpumask_weight(sched_group_cpus(group))) { |
5755 | printk(KERN_CONT "\n"); |
5756 | printk(KERN_ERR "ERROR: empty group\n"); |
5757 | break; |
5758 | } |
5759 | |
5760 | if (!(sd->flags & SD_OVERLAP) && |
5761 | cpumask_intersects(groupmask, sched_group_cpus(group))) { |
5762 | printk(KERN_CONT "\n"); |
5763 | printk(KERN_ERR "ERROR: repeated CPUs\n"); |
5764 | break; |
5765 | } |
5766 | |
5767 | cpumask_or(groupmask, groupmask, sched_group_cpus(group)); |
5768 | |
5769 | cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); |
5770 | |
5771 | printk(KERN_CONT " %s", str); |
5772 | if (group->sgp->power != SCHED_POWER_SCALE) { |
5773 | printk(KERN_CONT " (cpu_power = %d)", |
5774 | group->sgp->power); |
5775 | } |
5776 | |
5777 | group = group->next; |
5778 | } while (group != sd->groups); |
5779 | printk(KERN_CONT "\n"); |
5780 | |
5781 | if (!cpumask_equal(sched_domain_span(sd), groupmask)) |
5782 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); |
5783 | |
5784 | if (sd->parent && |
5785 | !cpumask_subset(groupmask, sched_domain_span(sd->parent))) |
5786 | printk(KERN_ERR "ERROR: parent span is not a superset " |
5787 | "of domain->span\n"); |
5788 | return 0; |
5789 | } |
5790 | |
5791 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
5792 | { |
5793 | int level = 0; |
5794 | |
5795 | if (!sched_debug_enabled) |
5796 | return; |
5797 | |
5798 | if (!sd) { |
5799 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); |
5800 | return; |
5801 | } |
5802 | |
5803 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5804 | |
5805 | for (;;) { |
5806 | if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) |
5807 | break; |
5808 | level++; |
5809 | sd = sd->parent; |
5810 | if (!sd) |
5811 | break; |
5812 | } |
5813 | } |
5814 | #else /* !CONFIG_SCHED_DEBUG */ |
5815 | # define sched_domain_debug(sd, cpu) do { } while (0) |
5816 | static inline bool sched_debug(void) |
5817 | { |
5818 | return false; |
5819 | } |
5820 | #endif /* CONFIG_SCHED_DEBUG */ |
5821 | |
5822 | static int sd_degenerate(struct sched_domain *sd) |
5823 | { |
5824 | if (cpumask_weight(sched_domain_span(sd)) == 1) |
5825 | return 1; |
5826 | |
5827 | /* Following flags need at least 2 groups */ |
5828 | if (sd->flags & (SD_LOAD_BALANCE | |
5829 | SD_BALANCE_NEWIDLE | |
5830 | SD_BALANCE_FORK | |
5831 | SD_BALANCE_EXEC | |
5832 | SD_SHARE_CPUPOWER | |
5833 | SD_SHARE_PKG_RESOURCES)) { |
5834 | if (sd->groups != sd->groups->next) |
5835 | return 0; |
5836 | } |
5837 | |
5838 | /* Following flags don't use groups */ |
5839 | if (sd->flags & (SD_WAKE_AFFINE)) |
5840 | return 0; |
5841 | |
5842 | return 1; |
5843 | } |
5844 | |
5845 | static int |
5846 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) |
5847 | { |
5848 | unsigned long cflags = sd->flags, pflags = parent->flags; |
5849 | |
5850 | if (sd_degenerate(parent)) |
5851 | return 1; |
5852 | |
5853 | if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) |
5854 | return 0; |
5855 | |
5856 | /* Flags needing groups don't count if only 1 group in parent */ |
5857 | if (parent->groups == parent->groups->next) { |
5858 | pflags &= ~(SD_LOAD_BALANCE | |
5859 | SD_BALANCE_NEWIDLE | |
5860 | SD_BALANCE_FORK | |
5861 | SD_BALANCE_EXEC | |
5862 | SD_SHARE_CPUPOWER | |
5863 | SD_SHARE_PKG_RESOURCES); |
5864 | if (nr_node_ids == 1) |
5865 | pflags &= ~SD_SERIALIZE; |
5866 | } |
5867 | if (~cflags & pflags) |
5868 | return 0; |
5869 | |
5870 | return 1; |
5871 | } |
5872 | |
5873 | static void free_rootdomain(struct rcu_head *rcu) |
5874 | { |
5875 | struct root_domain *rd = container_of(rcu, struct root_domain, rcu); |
5876 | |
5877 | cpupri_cleanup(&rd->cpupri); |
5878 | free_cpumask_var(rd->rto_mask); |
5879 | free_cpumask_var(rd->online); |
5880 | free_cpumask_var(rd->span); |
5881 | kfree(rd); |
5882 | } |
5883 | |
5884 | static void rq_attach_root(struct rq *rq, struct root_domain *rd) |
5885 | { |
5886 | struct root_domain *old_rd = NULL; |
5887 | unsigned long flags; |
5888 | |
5889 | raw_spin_lock_irqsave(&rq->lock, flags); |
5890 | |
5891 | if (rq->rd) { |
5892 | old_rd = rq->rd; |
5893 | |
5894 | if (cpumask_test_cpu(rq->cpu, old_rd->online)) |
5895 | set_rq_offline(rq); |
5896 | |
5897 | cpumask_clear_cpu(rq->cpu, old_rd->span); |
5898 | |
5899 | /* |
5900 | * If we dont want to free the old_rt yet then |
5901 | * set old_rd to NULL to skip the freeing later |
5902 | * in this function: |
5903 | */ |
5904 | if (!atomic_dec_and_test(&old_rd->refcount)) |
5905 | old_rd = NULL; |
5906 | } |
5907 | |
5908 | atomic_inc(&rd->refcount); |
5909 | rq->rd = rd; |
5910 | |
5911 | cpumask_set_cpu(rq->cpu, rd->span); |
5912 | if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) |
5913 | set_rq_online(rq); |
5914 | |
5915 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5916 | |
5917 | if (old_rd) |
5918 | call_rcu_sched(&old_rd->rcu, free_rootdomain); |
5919 | } |
5920 | |
5921 | static int init_rootdomain(struct root_domain *rd) |
5922 | { |
5923 | memset(rd, 0, sizeof(*rd)); |
5924 | |
5925 | if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) |
5926 | goto out; |
5927 | if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) |
5928 | goto free_span; |
5929 | if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) |
5930 | goto free_online; |
5931 | |
5932 | if (cpupri_init(&rd->cpupri) != 0) |
5933 | goto free_rto_mask; |
5934 | return 0; |
5935 | |
5936 | free_rto_mask: |
5937 | free_cpumask_var(rd->rto_mask); |
5938 | free_online: |
5939 | free_cpumask_var(rd->online); |
5940 | free_span: |
5941 | free_cpumask_var(rd->span); |
5942 | out: |
5943 | return -ENOMEM; |
5944 | } |
5945 | |
5946 | /* |
5947 | * By default the system creates a single root-domain with all cpus as |
5948 | * members (mimicking the global state we have today). |
5949 | */ |
5950 | struct root_domain def_root_domain; |
5951 | |
5952 | static void init_defrootdomain(void) |
5953 | { |
5954 | init_rootdomain(&def_root_domain); |
5955 | |
5956 | atomic_set(&def_root_domain.refcount, 1); |
5957 | } |
5958 | |
5959 | static struct root_domain *alloc_rootdomain(void) |
5960 | { |
5961 | struct root_domain *rd; |
5962 | |
5963 | rd = kmalloc(sizeof(*rd), GFP_KERNEL); |
5964 | if (!rd) |
5965 | return NULL; |
5966 | |
5967 | if (init_rootdomain(rd) != 0) { |
5968 | kfree(rd); |
5969 | return NULL; |
5970 | } |
5971 | |
5972 | return rd; |
5973 | } |
5974 | |
5975 | static void free_sched_groups(struct sched_group *sg, int free_sgp) |
5976 | { |
5977 | struct sched_group *tmp, *first; |
5978 | |
5979 | if (!sg) |
5980 | return; |
5981 | |
5982 | first = sg; |
5983 | do { |
5984 | tmp = sg->next; |
5985 | |
5986 | if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) |
5987 | kfree(sg->sgp); |
5988 | |
5989 | kfree(sg); |
5990 | sg = tmp; |
5991 | } while (sg != first); |
5992 | } |
5993 | |
5994 | static void free_sched_domain(struct rcu_head *rcu) |
5995 | { |
5996 | struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); |
5997 | |
5998 | /* |
5999 | * If its an overlapping domain it has private groups, iterate and |
6000 | * nuke them all. |
6001 | */ |
6002 | if (sd->flags & SD_OVERLAP) { |
6003 | free_sched_groups(sd->groups, 1); |
6004 | } else if (atomic_dec_and_test(&sd->groups->ref)) { |
6005 | kfree(sd->groups->sgp); |
6006 | kfree(sd->groups); |
6007 | } |
6008 | kfree(sd); |
6009 | } |
6010 | |
6011 | static void destroy_sched_domain(struct sched_domain *sd, int cpu) |
6012 | { |
6013 | call_rcu(&sd->rcu, free_sched_domain); |
6014 | } |
6015 | |
6016 | static void destroy_sched_domains(struct sched_domain *sd, int cpu) |
6017 | { |
6018 | for (; sd; sd = sd->parent) |
6019 | destroy_sched_domain(sd, cpu); |
6020 | } |
6021 | |
6022 | /* |
6023 | * Keep a special pointer to the highest sched_domain that has |
6024 | * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this |
6025 | * allows us to avoid some pointer chasing select_idle_sibling(). |
6026 | * |
6027 | * Also keep a unique ID per domain (we use the first cpu number in |
6028 | * the cpumask of the domain), this allows us to quickly tell if |
6029 | * two cpus are in the same cache domain, see cpus_share_cache(). |
6030 | */ |
6031 | DEFINE_PER_CPU(struct sched_domain *, sd_llc); |
6032 | DEFINE_PER_CPU(int, sd_llc_id); |
6033 | |
6034 | static void update_top_cache_domain(int cpu) |
6035 | { |
6036 | struct sched_domain *sd; |
6037 | int id = cpu; |
6038 | |
6039 | sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); |
6040 | if (sd) |
6041 | id = cpumask_first(sched_domain_span(sd)); |
6042 | |
6043 | rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); |
6044 | per_cpu(sd_llc_id, cpu) = id; |
6045 | } |
6046 | |
6047 | /* |
6048 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
6049 | * hold the hotplug lock. |
6050 | */ |
6051 | static void |
6052 | cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) |
6053 | { |
6054 | struct rq *rq = cpu_rq(cpu); |
6055 | struct sched_domain *tmp; |
6056 | |
6057 | /* Remove the sched domains which do not contribute to scheduling. */ |
6058 | for (tmp = sd; tmp; ) { |
6059 | struct sched_domain *parent = tmp->parent; |
6060 | if (!parent) |
6061 | break; |
6062 | |
6063 | if (sd_parent_degenerate(tmp, parent)) { |
6064 | tmp->parent = parent->parent; |
6065 | if (parent->parent) |
6066 | parent->parent->child = tmp; |
6067 | destroy_sched_domain(parent, cpu); |
6068 | } else |
6069 | tmp = tmp->parent; |
6070 | } |
6071 | |
6072 | if (sd && sd_degenerate(sd)) { |
6073 | tmp = sd; |
6074 | sd = sd->parent; |
6075 | destroy_sched_domain(tmp, cpu); |
6076 | if (sd) |
6077 | sd->child = NULL; |
6078 | } |
6079 | |
6080 | sched_domain_debug(sd, cpu); |
6081 | |
6082 | rq_attach_root(rq, rd); |
6083 | tmp = rq->sd; |
6084 | rcu_assign_pointer(rq->sd, sd); |
6085 | destroy_sched_domains(tmp, cpu); |
6086 | |
6087 | update_top_cache_domain(cpu); |
6088 | } |
6089 | |
6090 | /* cpus with isolated domains */ |
6091 | static cpumask_var_t cpu_isolated_map; |
6092 | |
6093 | /* Setup the mask of cpus configured for isolated domains */ |
6094 | static int __init isolated_cpu_setup(char *str) |
6095 | { |
6096 | alloc_bootmem_cpumask_var(&cpu_isolated_map); |
6097 | cpulist_parse(str, cpu_isolated_map); |
6098 | return 1; |
6099 | } |
6100 | |
6101 | __setup("isolcpus=", isolated_cpu_setup); |
6102 | |
6103 | static const struct cpumask *cpu_cpu_mask(int cpu) |
6104 | { |
6105 | return cpumask_of_node(cpu_to_node(cpu)); |
6106 | } |
6107 | |
6108 | struct sd_data { |
6109 | struct sched_domain **__percpu sd; |
6110 | struct sched_group **__percpu sg; |
6111 | struct sched_group_power **__percpu sgp; |
6112 | }; |
6113 | |
6114 | struct s_data { |
6115 | struct sched_domain ** __percpu sd; |
6116 | struct root_domain *rd; |
6117 | }; |
6118 | |
6119 | enum s_alloc { |
6120 | sa_rootdomain, |
6121 | sa_sd, |
6122 | sa_sd_storage, |
6123 | sa_none, |
6124 | }; |
6125 | |
6126 | struct sched_domain_topology_level; |
6127 | |
6128 | typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); |
6129 | typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); |
6130 | |
6131 | #define SDTL_OVERLAP 0x01 |
6132 | |
6133 | struct sched_domain_topology_level { |
6134 | sched_domain_init_f init; |
6135 | sched_domain_mask_f mask; |
6136 | int flags; |
6137 | int numa_level; |
6138 | struct sd_data data; |
6139 | }; |
6140 | |
6141 | /* |
6142 | * Build an iteration mask that can exclude certain CPUs from the upwards |
6143 | * domain traversal. |
6144 | * |
6145 | * Asymmetric node setups can result in situations where the domain tree is of |
6146 | * unequal depth, make sure to skip domains that already cover the entire |
6147 | * range. |
6148 | * |
6149 | * In that case build_sched_domains() will have terminated the iteration early |
6150 | * and our sibling sd spans will be empty. Domains should always include the |
6151 | * cpu they're built on, so check that. |
6152 | * |
6153 | */ |
6154 | static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) |
6155 | { |
6156 | const struct cpumask *span = sched_domain_span(sd); |
6157 | struct sd_data *sdd = sd->private; |
6158 | struct sched_domain *sibling; |
6159 | int i; |
6160 | |
6161 | for_each_cpu(i, span) { |
6162 | sibling = *per_cpu_ptr(sdd->sd, i); |
6163 | if (!cpumask_test_cpu(i, sched_domain_span(sibling))) |
6164 | continue; |
6165 | |
6166 | cpumask_set_cpu(i, sched_group_mask(sg)); |
6167 | } |
6168 | } |
6169 | |
6170 | /* |
6171 | * Return the canonical balance cpu for this group, this is the first cpu |
6172 | * of this group that's also in the iteration mask. |
6173 | */ |
6174 | int group_balance_cpu(struct sched_group *sg) |
6175 | { |
6176 | return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); |
6177 | } |
6178 | |
6179 | static int |
6180 | build_overlap_sched_groups(struct sched_domain *sd, int cpu) |
6181 | { |
6182 | struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; |
6183 | const struct cpumask *span = sched_domain_span(sd); |
6184 | struct cpumask *covered = sched_domains_tmpmask; |
6185 | struct sd_data *sdd = sd->private; |
6186 | struct sched_domain *child; |
6187 | int i; |
6188 | |
6189 | cpumask_clear(covered); |
6190 | |
6191 | for_each_cpu(i, span) { |
6192 | struct cpumask *sg_span; |
6193 | |
6194 | if (cpumask_test_cpu(i, covered)) |
6195 | continue; |
6196 | |
6197 | child = *per_cpu_ptr(sdd->sd, i); |
6198 | |
6199 | /* See the comment near build_group_mask(). */ |
6200 | if (!cpumask_test_cpu(i, sched_domain_span(child))) |
6201 | continue; |
6202 | |
6203 | sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), |
6204 | GFP_KERNEL, cpu_to_node(cpu)); |
6205 | |
6206 | if (!sg) |
6207 | goto fail; |
6208 | |
6209 | sg_span = sched_group_cpus(sg); |
6210 | if (child->child) { |
6211 | child = child->child; |
6212 | cpumask_copy(sg_span, sched_domain_span(child)); |
6213 | } else |
6214 | cpumask_set_cpu(i, sg_span); |
6215 | |
6216 | cpumask_or(covered, covered, sg_span); |
6217 | |
6218 | sg->sgp = *per_cpu_ptr(sdd->sgp, i); |
6219 | if (atomic_inc_return(&sg->sgp->ref) == 1) |
6220 | build_group_mask(sd, sg); |
6221 | |
6222 | /* |
6223 | * Initialize sgp->power such that even if we mess up the |
6224 | * domains and no possible iteration will get us here, we won't |
6225 | * die on a /0 trap. |
6226 | */ |
6227 | sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); |
6228 | |
6229 | /* |
6230 | * Make sure the first group of this domain contains the |
6231 | * canonical balance cpu. Otherwise the sched_domain iteration |
6232 | * breaks. See update_sg_lb_stats(). |
6233 | */ |
6234 | if ((!groups && cpumask_test_cpu(cpu, sg_span)) || |
6235 | group_balance_cpu(sg) == cpu) |
6236 | groups = sg; |
6237 | |
6238 | if (!first) |
6239 | first = sg; |
6240 | if (last) |
6241 | last->next = sg; |
6242 | last = sg; |
6243 | last->next = first; |
6244 | } |
6245 | sd->groups = groups; |
6246 | |
6247 | return 0; |
6248 | |
6249 | fail: |
6250 | free_sched_groups(first, 0); |
6251 | |
6252 | return -ENOMEM; |
6253 | } |
6254 | |
6255 | static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) |
6256 | { |
6257 | struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); |
6258 | struct sched_domain *child = sd->child; |
6259 | |
6260 | if (child) |
6261 | cpu = cpumask_first(sched_domain_span(child)); |
6262 | |
6263 | if (sg) { |
6264 | *sg = *per_cpu_ptr(sdd->sg, cpu); |
6265 | (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); |
6266 | atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ |
6267 | } |
6268 | |
6269 | return cpu; |
6270 | } |
6271 | |
6272 | /* |
6273 | * build_sched_groups will build a circular linked list of the groups |
6274 | * covered by the given span, and will set each group's ->cpumask correctly, |
6275 | * and ->cpu_power to 0. |
6276 | * |
6277 | * Assumes the sched_domain tree is fully constructed |
6278 | */ |
6279 | static int |
6280 | build_sched_groups(struct sched_domain *sd, int cpu) |
6281 | { |
6282 | struct sched_group *first = NULL, *last = NULL; |
6283 | struct sd_data *sdd = sd->private; |
6284 | const struct cpumask *span = sched_domain_span(sd); |
6285 | struct cpumask *covered; |
6286 | int i; |
6287 | |
6288 | get_group(cpu, sdd, &sd->groups); |
6289 | atomic_inc(&sd->groups->ref); |
6290 | |
6291 | if (cpu != cpumask_first(sched_domain_span(sd))) |
6292 | return 0; |
6293 | |
6294 | lockdep_assert_held(&sched_domains_mutex); |
6295 | covered = sched_domains_tmpmask; |
6296 | |
6297 | cpumask_clear(covered); |
6298 | |
6299 | for_each_cpu(i, span) { |
6300 | struct sched_group *sg; |
6301 | int group = get_group(i, sdd, &sg); |
6302 | int j; |
6303 | |
6304 | if (cpumask_test_cpu(i, covered)) |
6305 | continue; |
6306 | |
6307 | cpumask_clear(sched_group_cpus(sg)); |
6308 | sg->sgp->power = 0; |
6309 | cpumask_setall(sched_group_mask(sg)); |
6310 | |
6311 | for_each_cpu(j, span) { |
6312 | if (get_group(j, sdd, NULL) != group) |
6313 | continue; |
6314 | |
6315 | cpumask_set_cpu(j, covered); |
6316 | cpumask_set_cpu(j, sched_group_cpus(sg)); |
6317 | } |
6318 | |
6319 | if (!first) |
6320 | first = sg; |
6321 | if (last) |
6322 | last->next = sg; |
6323 | last = sg; |
6324 | } |
6325 | last->next = first; |
6326 | |
6327 | return 0; |
6328 | } |
6329 | |
6330 | /* |
6331 | * Initialize sched groups cpu_power. |
6332 | * |
6333 | * cpu_power indicates the capacity of sched group, which is used while |
6334 | * distributing the load between different sched groups in a sched domain. |
6335 | * Typically cpu_power for all the groups in a sched domain will be same unless |
6336 | * there are asymmetries in the topology. If there are asymmetries, group |
6337 | * having more cpu_power will pickup more load compared to the group having |
6338 | * less cpu_power. |
6339 | */ |
6340 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) |
6341 | { |
6342 | struct sched_group *sg = sd->groups; |
6343 | |
6344 | WARN_ON(!sd || !sg); |
6345 | |
6346 | do { |
6347 | sg->group_weight = cpumask_weight(sched_group_cpus(sg)); |
6348 | sg = sg->next; |
6349 | } while (sg != sd->groups); |
6350 | |
6351 | if (cpu != group_balance_cpu(sg)) |
6352 | return; |
6353 | |
6354 | update_group_power(sd, cpu); |
6355 | atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); |
6356 | } |
6357 | |
6358 | int __weak arch_sd_sibling_asym_packing(void) |
6359 | { |
6360 | return 0*SD_ASYM_PACKING; |
6361 | } |
6362 | |
6363 | /* |
6364 | * Initializers for schedule domains |
6365 | * Non-inlined to reduce accumulated stack pressure in build_sched_domains() |
6366 | */ |
6367 | |
6368 | #ifdef CONFIG_SCHED_DEBUG |
6369 | # define SD_INIT_NAME(sd, type) sd->name = #type |
6370 | #else |
6371 | # define SD_INIT_NAME(sd, type) do { } while (0) |
6372 | #endif |
6373 | |
6374 | #define SD_INIT_FUNC(type) \ |
6375 | static noinline struct sched_domain * \ |
6376 | sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ |
6377 | { \ |
6378 | struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ |
6379 | *sd = SD_##type##_INIT; \ |
6380 | SD_INIT_NAME(sd, type); \ |
6381 | sd->private = &tl->data; \ |
6382 | return sd; \ |
6383 | } |
6384 | |
6385 | SD_INIT_FUNC(CPU) |
6386 | #ifdef CONFIG_SCHED_SMT |
6387 | SD_INIT_FUNC(SIBLING) |
6388 | #endif |
6389 | #ifdef CONFIG_SCHED_MC |
6390 | SD_INIT_FUNC(MC) |
6391 | #endif |
6392 | #ifdef CONFIG_SCHED_BOOK |
6393 | SD_INIT_FUNC(BOOK) |
6394 | #endif |
6395 | |
6396 | static int default_relax_domain_level = -1; |
6397 | int sched_domain_level_max; |
6398 | |
6399 | static int __init setup_relax_domain_level(char *str) |
6400 | { |
6401 | if (kstrtoint(str, 0, &default_relax_domain_level)) |
6402 | pr_warn("Unable to set relax_domain_level\n"); |
6403 | |
6404 | return 1; |
6405 | } |
6406 | __setup("relax_domain_level=", setup_relax_domain_level); |
6407 | |
6408 | static void set_domain_attribute(struct sched_domain *sd, |
6409 | struct sched_domain_attr *attr) |
6410 | { |
6411 | int request; |
6412 | |
6413 | if (!attr || attr->relax_domain_level < 0) { |
6414 | if (default_relax_domain_level < 0) |
6415 | return; |
6416 | else |
6417 | request = default_relax_domain_level; |
6418 | } else |
6419 | request = attr->relax_domain_level; |
6420 | if (request < sd->level) { |
6421 | /* turn off idle balance on this domain */ |
6422 | sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
6423 | } else { |
6424 | /* turn on idle balance on this domain */ |
6425 | sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
6426 | } |
6427 | } |
6428 | |
6429 | static void __sdt_free(const struct cpumask *cpu_map); |
6430 | static int __sdt_alloc(const struct cpumask *cpu_map); |
6431 | |
6432 | static void __free_domain_allocs(struct s_data *d, enum s_alloc what, |
6433 | const struct cpumask *cpu_map) |
6434 | { |
6435 | switch (what) { |
6436 | case sa_rootdomain: |
6437 | if (!atomic_read(&d->rd->refcount)) |
6438 | free_rootdomain(&d->rd->rcu); /* fall through */ |
6439 | case sa_sd: |
6440 | free_percpu(d->sd); /* fall through */ |
6441 | case sa_sd_storage: |
6442 | __sdt_free(cpu_map); /* fall through */ |
6443 | case sa_none: |
6444 | break; |
6445 | } |
6446 | } |
6447 | |
6448 | static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, |
6449 | const struct cpumask *cpu_map) |
6450 | { |
6451 | memset(d, 0, sizeof(*d)); |
6452 | |
6453 | if (__sdt_alloc(cpu_map)) |
6454 | return sa_sd_storage; |
6455 | d->sd = alloc_percpu(struct sched_domain *); |
6456 | if (!d->sd) |
6457 | return sa_sd_storage; |
6458 | d->rd = alloc_rootdomain(); |
6459 | if (!d->rd) |
6460 | return sa_sd; |
6461 | return sa_rootdomain; |
6462 | } |
6463 | |
6464 | /* |
6465 | * NULL the sd_data elements we've used to build the sched_domain and |
6466 | * sched_group structure so that the subsequent __free_domain_allocs() |
6467 | * will not free the data we're using. |
6468 | */ |
6469 | static void claim_allocations(int cpu, struct sched_domain *sd) |
6470 | { |
6471 | struct sd_data *sdd = sd->private; |
6472 | |
6473 | WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); |
6474 | *per_cpu_ptr(sdd->sd, cpu) = NULL; |
6475 | |
6476 | if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) |
6477 | *per_cpu_ptr(sdd->sg, cpu) = NULL; |
6478 | |
6479 | if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) |
6480 | *per_cpu_ptr(sdd->sgp, cpu) = NULL; |
6481 | } |
6482 | |
6483 | #ifdef CONFIG_SCHED_SMT |
6484 | static const struct cpumask *cpu_smt_mask(int cpu) |
6485 | { |
6486 | return topology_thread_cpumask(cpu); |
6487 | } |
6488 | #endif |
6489 | |
6490 | /* |
6491 | * Topology list, bottom-up. |
6492 | */ |
6493 | static struct sched_domain_topology_level default_topology[] = { |
6494 | #ifdef CONFIG_SCHED_SMT |
6495 | { sd_init_SIBLING, cpu_smt_mask, }, |
6496 | #endif |
6497 | #ifdef CONFIG_SCHED_MC |
6498 | { sd_init_MC, cpu_coregroup_mask, }, |
6499 | #endif |
6500 | #ifdef CONFIG_SCHED_BOOK |
6501 | { sd_init_BOOK, cpu_book_mask, }, |
6502 | #endif |
6503 | { sd_init_CPU, cpu_cpu_mask, }, |
6504 | { NULL, }, |
6505 | }; |
6506 | |
6507 | static struct sched_domain_topology_level *sched_domain_topology = default_topology; |
6508 | |
6509 | #ifdef CONFIG_NUMA |
6510 | |
6511 | static int sched_domains_numa_levels; |
6512 | static int *sched_domains_numa_distance; |
6513 | static struct cpumask ***sched_domains_numa_masks; |
6514 | static int sched_domains_curr_level; |
6515 | |
6516 | static inline int sd_local_flags(int level) |
6517 | { |
6518 | if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) |
6519 | return 0; |
6520 | |
6521 | return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; |
6522 | } |
6523 | |
6524 | static struct sched_domain * |
6525 | sd_numa_init(struct sched_domain_topology_level *tl, int cpu) |
6526 | { |
6527 | struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); |
6528 | int level = tl->numa_level; |
6529 | int sd_weight = cpumask_weight( |
6530 | sched_domains_numa_masks[level][cpu_to_node(cpu)]); |
6531 | |
6532 | *sd = (struct sched_domain){ |
6533 | .min_interval = sd_weight, |
6534 | .max_interval = 2*sd_weight, |
6535 | .busy_factor = 32, |
6536 | .imbalance_pct = 125, |
6537 | .cache_nice_tries = 2, |
6538 | .busy_idx = 3, |
6539 | .idle_idx = 2, |
6540 | .newidle_idx = 0, |
6541 | .wake_idx = 0, |
6542 | .forkexec_idx = 0, |
6543 | |
6544 | .flags = 1*SD_LOAD_BALANCE |
6545 | | 1*SD_BALANCE_NEWIDLE |
6546 | | 0*SD_BALANCE_EXEC |
6547 | | 0*SD_BALANCE_FORK |
6548 | | 0*SD_BALANCE_WAKE |
6549 | | 0*SD_WAKE_AFFINE |
6550 | | 0*SD_PREFER_LOCAL |
6551 | | 0*SD_SHARE_CPUPOWER |
6552 | | 0*SD_SHARE_PKG_RESOURCES |
6553 | | 1*SD_SERIALIZE |
6554 | | 0*SD_PREFER_SIBLING |
6555 | | sd_local_flags(level) |
6556 | , |
6557 | .last_balance = jiffies, |
6558 | .balance_interval = sd_weight, |
6559 | }; |
6560 | SD_INIT_NAME(sd, NUMA); |
6561 | sd->private = &tl->data; |
6562 | |
6563 | /* |
6564 | * Ugly hack to pass state to sd_numa_mask()... |
6565 | */ |
6566 | sched_domains_curr_level = tl->numa_level; |
6567 | |
6568 | return sd; |
6569 | } |
6570 | |
6571 | static const struct cpumask *sd_numa_mask(int cpu) |
6572 | { |
6573 | return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; |
6574 | } |
6575 | |
6576 | static void sched_numa_warn(const char *str) |
6577 | { |
6578 | static int done = false; |
6579 | int i,j; |
6580 | |
6581 | if (done) |
6582 | return; |
6583 | |
6584 | done = true; |
6585 | |
6586 | printk(KERN_WARNING "ERROR: %s\n\n", str); |
6587 | |
6588 | for (i = 0; i < nr_node_ids; i++) { |
6589 | printk(KERN_WARNING " "); |
6590 | for (j = 0; j < nr_node_ids; j++) |
6591 | printk(KERN_CONT "%02d ", node_distance(i,j)); |
6592 | printk(KERN_CONT "\n"); |
6593 | } |
6594 | printk(KERN_WARNING "\n"); |
6595 | } |
6596 | |
6597 | static bool find_numa_distance(int distance) |
6598 | { |
6599 | int i; |
6600 | |
6601 | if (distance == node_distance(0, 0)) |
6602 | return true; |
6603 | |
6604 | for (i = 0; i < sched_domains_numa_levels; i++) { |
6605 | if (sched_domains_numa_distance[i] == distance) |
6606 | return true; |
6607 | } |
6608 | |
6609 | return false; |
6610 | } |
6611 | |
6612 | static void sched_init_numa(void) |
6613 | { |
6614 | int next_distance, curr_distance = node_distance(0, 0); |
6615 | struct sched_domain_topology_level *tl; |
6616 | int level = 0; |
6617 | int i, j, k; |
6618 | |
6619 | sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); |
6620 | if (!sched_domains_numa_distance) |
6621 | return; |
6622 | |
6623 | /* |
6624 | * O(nr_nodes^2) deduplicating selection sort -- in order to find the |
6625 | * unique distances in the node_distance() table. |
6626 | * |
6627 | * Assumes node_distance(0,j) includes all distances in |
6628 | * node_distance(i,j) in order to avoid cubic time. |
6629 | */ |
6630 | next_distance = curr_distance; |
6631 | for (i = 0; i < nr_node_ids; i++) { |
6632 | for (j = 0; j < nr_node_ids; j++) { |
6633 | for (k = 0; k < nr_node_ids; k++) { |
6634 | int distance = node_distance(i, k); |
6635 | |
6636 | if (distance > curr_distance && |
6637 | (distance < next_distance || |
6638 | next_distance == curr_distance)) |
6639 | next_distance = distance; |
6640 | |
6641 | /* |
6642 | * While not a strong assumption it would be nice to know |
6643 | * about cases where if node A is connected to B, B is not |
6644 | * equally connected to A. |
6645 | */ |
6646 | if (sched_debug() && node_distance(k, i) != distance) |
6647 | sched_numa_warn("Node-distance not symmetric"); |
6648 | |
6649 | if (sched_debug() && i && !find_numa_distance(distance)) |
6650 | sched_numa_warn("Node-0 not representative"); |
6651 | } |
6652 | if (next_distance != curr_distance) { |
6653 | sched_domains_numa_distance[level++] = next_distance; |
6654 | sched_domains_numa_levels = level; |
6655 | curr_distance = next_distance; |
6656 | } else break; |
6657 | } |
6658 | |
6659 | /* |
6660 | * In case of sched_debug() we verify the above assumption. |
6661 | */ |
6662 | if (!sched_debug()) |
6663 | break; |
6664 | } |
6665 | /* |
6666 | * 'level' contains the number of unique distances, excluding the |
6667 | * identity distance node_distance(i,i). |
6668 | * |
6669 | * The sched_domains_nume_distance[] array includes the actual distance |
6670 | * numbers. |
6671 | */ |
6672 | |
6673 | sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); |
6674 | if (!sched_domains_numa_masks) |
6675 | return; |
6676 | |
6677 | /* |
6678 | * Now for each level, construct a mask per node which contains all |
6679 | * cpus of nodes that are that many hops away from us. |
6680 | */ |
6681 | for (i = 0; i < level; i++) { |
6682 | sched_domains_numa_masks[i] = |
6683 | kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); |
6684 | if (!sched_domains_numa_masks[i]) |
6685 | return; |
6686 | |
6687 | for (j = 0; j < nr_node_ids; j++) { |
6688 | struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); |
6689 | if (!mask) |
6690 | return; |
6691 | |
6692 | sched_domains_numa_masks[i][j] = mask; |
6693 | |
6694 | for (k = 0; k < nr_node_ids; k++) { |
6695 | if (node_distance(j, k) > sched_domains_numa_distance[i]) |
6696 | continue; |
6697 | |
6698 | cpumask_or(mask, mask, cpumask_of_node(k)); |
6699 | } |
6700 | } |
6701 | } |
6702 | |
6703 | tl = kzalloc((ARRAY_SIZE(default_topology) + level) * |
6704 | sizeof(struct sched_domain_topology_level), GFP_KERNEL); |
6705 | if (!tl) |
6706 | return; |
6707 | |
6708 | /* |
6709 | * Copy the default topology bits.. |
6710 | */ |
6711 | for (i = 0; default_topology[i].init; i++) |
6712 | tl[i] = default_topology[i]; |
6713 | |
6714 | /* |
6715 | * .. and append 'j' levels of NUMA goodness. |
6716 | */ |
6717 | for (j = 0; j < level; i++, j++) { |
6718 | tl[i] = (struct sched_domain_topology_level){ |
6719 | .init = sd_numa_init, |
6720 | .mask = sd_numa_mask, |
6721 | .flags = SDTL_OVERLAP, |
6722 | .numa_level = j, |
6723 | }; |
6724 | } |
6725 | |
6726 | sched_domain_topology = tl; |
6727 | } |
6728 | #else |
6729 | static inline void sched_init_numa(void) |
6730 | { |
6731 | } |
6732 | #endif /* CONFIG_NUMA */ |
6733 | |
6734 | static int __sdt_alloc(const struct cpumask *cpu_map) |
6735 | { |
6736 | struct sched_domain_topology_level *tl; |
6737 | int j; |
6738 | |
6739 | for (tl = sched_domain_topology; tl->init; tl++) { |
6740 | struct sd_data *sdd = &tl->data; |
6741 | |
6742 | sdd->sd = alloc_percpu(struct sched_domain *); |
6743 | if (!sdd->sd) |
6744 | return -ENOMEM; |
6745 | |
6746 | sdd->sg = alloc_percpu(struct sched_group *); |
6747 | if (!sdd->sg) |
6748 | return -ENOMEM; |
6749 | |
6750 | sdd->sgp = alloc_percpu(struct sched_group_power *); |
6751 | if (!sdd->sgp) |
6752 | return -ENOMEM; |
6753 | |
6754 | for_each_cpu(j, cpu_map) { |
6755 | struct sched_domain *sd; |
6756 | struct sched_group *sg; |
6757 | struct sched_group_power *sgp; |
6758 | |
6759 | sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), |
6760 | GFP_KERNEL, cpu_to_node(j)); |
6761 | if (!sd) |
6762 | return -ENOMEM; |
6763 | |
6764 | *per_cpu_ptr(sdd->sd, j) = sd; |
6765 | |
6766 | sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), |
6767 | GFP_KERNEL, cpu_to_node(j)); |
6768 | if (!sg) |
6769 | return -ENOMEM; |
6770 | |
6771 | sg->next = sg; |
6772 | |
6773 | *per_cpu_ptr(sdd->sg, j) = sg; |
6774 | |
6775 | sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), |
6776 | GFP_KERNEL, cpu_to_node(j)); |
6777 | if (!sgp) |
6778 | return -ENOMEM; |
6779 | |
6780 | *per_cpu_ptr(sdd->sgp, j) = sgp; |
6781 | } |
6782 | } |
6783 | |
6784 | return 0; |
6785 | } |
6786 | |
6787 | static void __sdt_free(const struct cpumask *cpu_map) |
6788 | { |
6789 | struct sched_domain_topology_level *tl; |
6790 | int j; |
6791 | |
6792 | for (tl = sched_domain_topology; tl->init; tl++) { |
6793 | struct sd_data *sdd = &tl->data; |
6794 | |
6795 | for_each_cpu(j, cpu_map) { |
6796 | struct sched_domain *sd; |
6797 | |
6798 | if (sdd->sd) { |
6799 | sd = *per_cpu_ptr(sdd->sd, j); |
6800 | if (sd && (sd->flags & SD_OVERLAP)) |
6801 | free_sched_groups(sd->groups, 0); |
6802 | kfree(*per_cpu_ptr(sdd->sd, j)); |
6803 | } |
6804 | |
6805 | if (sdd->sg) |
6806 | kfree(*per_cpu_ptr(sdd->sg, j)); |
6807 | if (sdd->sgp) |
6808 | kfree(*per_cpu_ptr(sdd->sgp, j)); |
6809 | } |
6810 | free_percpu(sdd->sd); |
6811 | sdd->sd = NULL; |
6812 | free_percpu(sdd->sg); |
6813 | sdd->sg = NULL; |
6814 | free_percpu(sdd->sgp); |
6815 | sdd->sgp = NULL; |
6816 | } |
6817 | } |
6818 | |
6819 | struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, |
6820 | struct s_data *d, const struct cpumask *cpu_map, |
6821 | struct sched_domain_attr *attr, struct sched_domain *child, |
6822 | int cpu) |
6823 | { |
6824 | struct sched_domain *sd = tl->init(tl, cpu); |
6825 | if (!sd) |
6826 | return child; |
6827 | |
6828 | cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); |
6829 | if (child) { |
6830 | sd->level = child->level + 1; |
6831 | sched_domain_level_max = max(sched_domain_level_max, sd->level); |
6832 | child->parent = sd; |
6833 | } |
6834 | sd->child = child; |
6835 | set_domain_attribute(sd, attr); |
6836 | |
6837 | return sd; |
6838 | } |
6839 | |
6840 | /* |
6841 | * Build sched domains for a given set of cpus and attach the sched domains |
6842 | * to the individual cpus |
6843 | */ |
6844 | static int build_sched_domains(const struct cpumask *cpu_map, |
6845 | struct sched_domain_attr *attr) |
6846 | { |
6847 | enum s_alloc alloc_state = sa_none; |
6848 | struct sched_domain *sd; |
6849 | struct s_data d; |
6850 | int i, ret = -ENOMEM; |
6851 | |
6852 | alloc_state = __visit_domain_allocation_hell(&d, cpu_map); |
6853 | if (alloc_state != sa_rootdomain) |
6854 | goto error; |
6855 | |
6856 | /* Set up domains for cpus specified by the cpu_map. */ |
6857 | for_each_cpu(i, cpu_map) { |
6858 | struct sched_domain_topology_level *tl; |
6859 | |
6860 | sd = NULL; |
6861 | for (tl = sched_domain_topology; tl->init; tl++) { |
6862 | sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i); |
6863 | if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) |
6864 | sd->flags |= SD_OVERLAP; |
6865 | if (cpumask_equal(cpu_map, sched_domain_span(sd))) |
6866 | break; |
6867 | } |
6868 | |
6869 | while (sd->child) |
6870 | sd = sd->child; |
6871 | |
6872 | *per_cpu_ptr(d.sd, i) = sd; |
6873 | } |
6874 | |
6875 | /* Build the groups for the domains */ |
6876 | for_each_cpu(i, cpu_map) { |
6877 | for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { |
6878 | sd->span_weight = cpumask_weight(sched_domain_span(sd)); |
6879 | if (sd->flags & SD_OVERLAP) { |
6880 | if (build_overlap_sched_groups(sd, i)) |
6881 | goto error; |
6882 | } else { |
6883 | if (build_sched_groups(sd, i)) |
6884 | goto error; |
6885 | } |
6886 | } |
6887 | } |
6888 | |
6889 | /* Calculate CPU power for physical packages and nodes */ |
6890 | for (i = nr_cpumask_bits-1; i >= 0; i--) { |
6891 | if (!cpumask_test_cpu(i, cpu_map)) |
6892 | continue; |
6893 | |
6894 | for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { |
6895 | claim_allocations(i, sd); |
6896 | init_sched_groups_power(i, sd); |
6897 | } |
6898 | } |
6899 | |
6900 | /* Attach the domains */ |
6901 | rcu_read_lock(); |
6902 | for_each_cpu(i, cpu_map) { |
6903 | sd = *per_cpu_ptr(d.sd, i); |
6904 | cpu_attach_domain(sd, d.rd, i); |
6905 | } |
6906 | rcu_read_unlock(); |
6907 | |
6908 | ret = 0; |
6909 | error: |
6910 | __free_domain_allocs(&d, alloc_state, cpu_map); |
6911 | return ret; |
6912 | } |
6913 | |
6914 | static cpumask_var_t *doms_cur; /* current sched domains */ |
6915 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ |
6916 | static struct sched_domain_attr *dattr_cur; |
6917 | /* attribues of custom domains in 'doms_cur' */ |
6918 | |
6919 | /* |
6920 | * Special case: If a kmalloc of a doms_cur partition (array of |
6921 | * cpumask) fails, then fallback to a single sched domain, |
6922 | * as determined by the single cpumask fallback_doms. |
6923 | */ |
6924 | static cpumask_var_t fallback_doms; |
6925 | |
6926 | /* |
6927 | * arch_update_cpu_topology lets virtualized architectures update the |
6928 | * cpu core maps. It is supposed to return 1 if the topology changed |
6929 | * or 0 if it stayed the same. |
6930 | */ |
6931 | int __attribute__((weak)) arch_update_cpu_topology(void) |
6932 | { |
6933 | return 0; |
6934 | } |
6935 | |
6936 | cpumask_var_t *alloc_sched_domains(unsigned int ndoms) |
6937 | { |
6938 | int i; |
6939 | cpumask_var_t *doms; |
6940 | |
6941 | doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); |
6942 | if (!doms) |
6943 | return NULL; |
6944 | for (i = 0; i < ndoms; i++) { |
6945 | if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { |
6946 | free_sched_domains(doms, i); |
6947 | return NULL; |
6948 | } |
6949 | } |
6950 | return doms; |
6951 | } |
6952 | |
6953 | void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) |
6954 | { |
6955 | unsigned int i; |
6956 | for (i = 0; i < ndoms; i++) |
6957 | free_cpumask_var(doms[i]); |
6958 | kfree(doms); |
6959 | } |
6960 | |
6961 | /* |
6962 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
6963 | * For now this just excludes isolated cpus, but could be used to |
6964 | * exclude other special cases in the future. |
6965 | */ |
6966 | static int init_sched_domains(const struct cpumask *cpu_map) |
6967 | { |
6968 | int err; |
6969 | |
6970 | arch_update_cpu_topology(); |
6971 | ndoms_cur = 1; |
6972 | doms_cur = alloc_sched_domains(ndoms_cur); |
6973 | if (!doms_cur) |
6974 | doms_cur = &fallback_doms; |
6975 | cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); |
6976 | err = build_sched_domains(doms_cur[0], NULL); |
6977 | register_sched_domain_sysctl(); |
6978 | |
6979 | return err; |
6980 | } |
6981 | |
6982 | /* |
6983 | * Detach sched domains from a group of cpus specified in cpu_map |
6984 | * These cpus will now be attached to the NULL domain |
6985 | */ |
6986 | static void detach_destroy_domains(const struct cpumask *cpu_map) |
6987 | { |
6988 | int i; |
6989 | |
6990 | rcu_read_lock(); |
6991 | for_each_cpu(i, cpu_map) |
6992 | cpu_attach_domain(NULL, &def_root_domain, i); |
6993 | rcu_read_unlock(); |
6994 | } |
6995 | |
6996 | /* handle null as "default" */ |
6997 | static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, |
6998 | struct sched_domain_attr *new, int idx_new) |
6999 | { |
7000 | struct sched_domain_attr tmp; |
7001 | |
7002 | /* fast path */ |
7003 | if (!new && !cur) |
7004 | return 1; |
7005 | |
7006 | tmp = SD_ATTR_INIT; |
7007 | return !memcmp(cur ? (cur + idx_cur) : &tmp, |
7008 | new ? (new + idx_new) : &tmp, |
7009 | sizeof(struct sched_domain_attr)); |
7010 | } |
7011 | |
7012 | /* |
7013 | * Partition sched domains as specified by the 'ndoms_new' |
7014 | * cpumasks in the array doms_new[] of cpumasks. This compares |
7015 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
7016 | * It destroys each deleted domain and builds each new domain. |
7017 | * |
7018 | * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. |
7019 | * The masks don't intersect (don't overlap.) We should setup one |
7020 | * sched domain for each mask. CPUs not in any of the cpumasks will |
7021 | * not be load balanced. If the same cpumask appears both in the |
7022 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
7023 | * it as it is. |
7024 | * |
7025 | * The passed in 'doms_new' should be allocated using |
7026 | * alloc_sched_domains. This routine takes ownership of it and will |
7027 | * free_sched_domains it when done with it. If the caller failed the |
7028 | * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, |
7029 | * and partition_sched_domains() will fallback to the single partition |
7030 | * 'fallback_doms', it also forces the domains to be rebuilt. |
7031 | * |
7032 | * If doms_new == NULL it will be replaced with cpu_online_mask. |
7033 | * ndoms_new == 0 is a special case for destroying existing domains, |
7034 | * and it will not create the default domain. |
7035 | * |
7036 | * Call with hotplug lock held |
7037 | */ |
7038 | void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], |
7039 | struct sched_domain_attr *dattr_new) |
7040 | { |
7041 | int i, j, n; |
7042 | int new_topology; |
7043 | |
7044 | mutex_lock(&sched_domains_mutex); |
7045 | |
7046 | /* always unregister in case we don't destroy any domains */ |
7047 | unregister_sched_domain_sysctl(); |
7048 | |
7049 | /* Let architecture update cpu core mappings. */ |
7050 | new_topology = arch_update_cpu_topology(); |
7051 | |
7052 | n = doms_new ? ndoms_new : 0; |
7053 | |
7054 | /* Destroy deleted domains */ |
7055 | for (i = 0; i < ndoms_cur; i++) { |
7056 | for (j = 0; j < n && !new_topology; j++) { |
7057 | if (cpumask_equal(doms_cur[i], doms_new[j]) |
7058 | && dattrs_equal(dattr_cur, i, dattr_new, j)) |
7059 | goto match1; |
7060 | } |
7061 | /* no match - a current sched domain not in new doms_new[] */ |
7062 | detach_destroy_domains(doms_cur[i]); |
7063 | match1: |
7064 | ; |
7065 | } |
7066 | |
7067 | if (doms_new == NULL) { |
7068 | ndoms_cur = 0; |
7069 | doms_new = &fallback_doms; |
7070 | cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); |
7071 | WARN_ON_ONCE(dattr_new); |
7072 | } |
7073 | |
7074 | /* Build new domains */ |
7075 | for (i = 0; i < ndoms_new; i++) { |
7076 | for (j = 0; j < ndoms_cur && !new_topology; j++) { |
7077 | if (cpumask_equal(doms_new[i], doms_cur[j]) |
7078 | && dattrs_equal(dattr_new, i, dattr_cur, j)) |
7079 | goto match2; |
7080 | } |
7081 | /* no match - add a new doms_new */ |
7082 | build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); |
7083 | match2: |
7084 | ; |
7085 | } |
7086 | |
7087 | /* Remember the new sched domains */ |
7088 | if (doms_cur != &fallback_doms) |
7089 | free_sched_domains(doms_cur, ndoms_cur); |
7090 | kfree(dattr_cur); /* kfree(NULL) is safe */ |
7091 | doms_cur = doms_new; |
7092 | dattr_cur = dattr_new; |
7093 | ndoms_cur = ndoms_new; |
7094 | |
7095 | register_sched_domain_sysctl(); |
7096 | |
7097 | mutex_unlock(&sched_domains_mutex); |
7098 | } |
7099 | |
7100 | /* |
7101 | * Update cpusets according to cpu_active mask. If cpusets are |
7102 | * disabled, cpuset_update_active_cpus() becomes a simple wrapper |
7103 | * around partition_sched_domains(). |
7104 | */ |
7105 | static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, |
7106 | void *hcpu) |
7107 | { |
7108 | switch (action & ~CPU_TASKS_FROZEN) { |
7109 | case CPU_ONLINE: |
7110 | case CPU_DOWN_FAILED: |
7111 | cpuset_update_active_cpus(); |
7112 | return NOTIFY_OK; |
7113 | default: |
7114 | return NOTIFY_DONE; |
7115 | } |
7116 | } |
7117 | |
7118 | static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, |
7119 | void *hcpu) |
7120 | { |
7121 | switch (action & ~CPU_TASKS_FROZEN) { |
7122 | case CPU_DOWN_PREPARE: |
7123 | cpuset_update_active_cpus(); |
7124 | return NOTIFY_OK; |
7125 | default: |
7126 | return NOTIFY_DONE; |
7127 | } |
7128 | } |
7129 | |
7130 | void __init sched_init_smp(void) |
7131 | { |
7132 | cpumask_var_t non_isolated_cpus; |
7133 | |
7134 | alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); |
7135 | alloc_cpumask_var(&fallback_doms, GFP_KERNEL); |
7136 | |
7137 | sched_init_numa(); |
7138 | |
7139 | get_online_cpus(); |
7140 | mutex_lock(&sched_domains_mutex); |
7141 | init_sched_domains(cpu_active_mask); |
7142 | cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); |
7143 | if (cpumask_empty(non_isolated_cpus)) |
7144 | cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); |
7145 | mutex_unlock(&sched_domains_mutex); |
7146 | put_online_cpus(); |
7147 | |
7148 | hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); |
7149 | hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); |
7150 | |
7151 | /* RT runtime code needs to handle some hotplug events */ |
7152 | hotcpu_notifier(update_runtime, 0); |
7153 | |
7154 | init_hrtick(); |
7155 | |
7156 | /* Move init over to a non-isolated CPU */ |
7157 | if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) |
7158 | BUG(); |
7159 | sched_init_granularity(); |
7160 | free_cpumask_var(non_isolated_cpus); |
7161 | |
7162 | init_sched_rt_class(); |
7163 | } |
7164 | #else |
7165 | void __init sched_init_smp(void) |
7166 | { |
7167 | sched_init_granularity(); |
7168 | } |
7169 | #endif /* CONFIG_SMP */ |
7170 | |
7171 | const_debug unsigned int sysctl_timer_migration = 1; |
7172 | |
7173 | int in_sched_functions(unsigned long addr) |
7174 | { |
7175 | return in_lock_functions(addr) || |
7176 | (addr >= (unsigned long)__sched_text_start |
7177 | && addr < (unsigned long)__sched_text_end); |
7178 | } |
7179 | |
7180 | #ifdef CONFIG_CGROUP_SCHED |
7181 | struct task_group root_task_group; |
7182 | #endif |
7183 | |
7184 | DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask); |
7185 | |
7186 | void __init sched_init(void) |
7187 | { |
7188 | int i, j; |
7189 | unsigned long alloc_size = 0, ptr; |
7190 | |
7191 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7192 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); |
7193 | #endif |
7194 | #ifdef CONFIG_RT_GROUP_SCHED |
7195 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); |
7196 | #endif |
7197 | #ifdef CONFIG_CPUMASK_OFFSTACK |
7198 | alloc_size += num_possible_cpus() * cpumask_size(); |
7199 | #endif |
7200 | if (alloc_size) { |
7201 | ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); |
7202 | |
7203 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7204 | root_task_group.se = (struct sched_entity **)ptr; |
7205 | ptr += nr_cpu_ids * sizeof(void **); |
7206 | |
7207 | root_task_group.cfs_rq = (struct cfs_rq **)ptr; |
7208 | ptr += nr_cpu_ids * sizeof(void **); |
7209 | |
7210 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
7211 | #ifdef CONFIG_RT_GROUP_SCHED |
7212 | root_task_group.rt_se = (struct sched_rt_entity **)ptr; |
7213 | ptr += nr_cpu_ids * sizeof(void **); |
7214 | |
7215 | root_task_group.rt_rq = (struct rt_rq **)ptr; |
7216 | ptr += nr_cpu_ids * sizeof(void **); |
7217 | |
7218 | #endif /* CONFIG_RT_GROUP_SCHED */ |
7219 | #ifdef CONFIG_CPUMASK_OFFSTACK |
7220 | for_each_possible_cpu(i) { |
7221 | per_cpu(load_balance_tmpmask, i) = (void *)ptr; |
7222 | ptr += cpumask_size(); |
7223 | } |
7224 | #endif /* CONFIG_CPUMASK_OFFSTACK */ |
7225 | } |
7226 | |
7227 | #ifdef CONFIG_SMP |
7228 | init_defrootdomain(); |
7229 | #endif |
7230 | |
7231 | init_rt_bandwidth(&def_rt_bandwidth, |
7232 | global_rt_period(), global_rt_runtime()); |
7233 | |
7234 | #ifdef CONFIG_RT_GROUP_SCHED |
7235 | init_rt_bandwidth(&root_task_group.rt_bandwidth, |
7236 | global_rt_period(), global_rt_runtime()); |
7237 | #endif /* CONFIG_RT_GROUP_SCHED */ |
7238 | |
7239 | #ifdef CONFIG_CGROUP_SCHED |
7240 | list_add(&root_task_group.list, &task_groups); |
7241 | INIT_LIST_HEAD(&root_task_group.children); |
7242 | INIT_LIST_HEAD(&root_task_group.siblings); |
7243 | autogroup_init(&init_task); |
7244 | |
7245 | #endif /* CONFIG_CGROUP_SCHED */ |
7246 | |
7247 | #ifdef CONFIG_CGROUP_CPUACCT |
7248 | root_cpuacct.cpustat = &kernel_cpustat; |
7249 | root_cpuacct.cpuusage = alloc_percpu(u64); |
7250 | /* Too early, not expected to fail */ |
7251 | BUG_ON(!root_cpuacct.cpuusage); |
7252 | #endif |
7253 | for_each_possible_cpu(i) { |
7254 | struct rq *rq; |
7255 | |
7256 | rq = cpu_rq(i); |
7257 | raw_spin_lock_init(&rq->lock); |
7258 | rq->nr_running = 0; |
7259 | rq->calc_load_active = 0; |
7260 | rq->calc_load_update = jiffies + LOAD_FREQ; |
7261 | init_cfs_rq(&rq->cfs); |
7262 | init_rt_rq(&rq->rt, rq); |
7263 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7264 | root_task_group.shares = ROOT_TASK_GROUP_LOAD; |
7265 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); |
7266 | /* |
7267 | * How much cpu bandwidth does root_task_group get? |
7268 | * |
7269 | * In case of task-groups formed thr' the cgroup filesystem, it |
7270 | * gets 100% of the cpu resources in the system. This overall |
7271 | * system cpu resource is divided among the tasks of |
7272 | * root_task_group and its child task-groups in a fair manner, |
7273 | * based on each entity's (task or task-group's) weight |
7274 | * (se->load.weight). |
7275 | * |
7276 | * In other words, if root_task_group has 10 tasks of weight |
7277 | * 1024) and two child groups A0 and A1 (of weight 1024 each), |
7278 | * then A0's share of the cpu resource is: |
7279 | * |
7280 | * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% |
7281 | * |
7282 | * We achieve this by letting root_task_group's tasks sit |
7283 | * directly in rq->cfs (i.e root_task_group->se[] = NULL). |
7284 | */ |
7285 | init_cfs_bandwidth(&root_task_group.cfs_bandwidth); |
7286 | init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); |
7287 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
7288 | |
7289 | rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; |
7290 | #ifdef CONFIG_RT_GROUP_SCHED |
7291 | INIT_LIST_HEAD(&rq->leaf_rt_rq_list); |
7292 | init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); |
7293 | #endif |
7294 | |
7295 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
7296 | rq->cpu_load[j] = 0; |
7297 | |
7298 | rq->last_load_update_tick = jiffies; |
7299 | |
7300 | #ifdef CONFIG_SMP |
7301 | rq->sd = NULL; |
7302 | rq->rd = NULL; |
7303 | rq->cpu_power = SCHED_POWER_SCALE; |
7304 | rq->post_schedule = 0; |
7305 | rq->active_balance = 0; |
7306 | rq->next_balance = jiffies; |
7307 | rq->push_cpu = 0; |
7308 | rq->cpu = i; |
7309 | rq->online = 0; |
7310 | rq->idle_stamp = 0; |
7311 | rq->avg_idle = 2*sysctl_sched_migration_cost; |
7312 | |
7313 | INIT_LIST_HEAD(&rq->cfs_tasks); |
7314 | |
7315 | rq_attach_root(rq, &def_root_domain); |
7316 | #ifdef CONFIG_NO_HZ |
7317 | rq->nohz_flags = 0; |
7318 | #endif |
7319 | #endif |
7320 | init_rq_hrtick(rq); |
7321 | atomic_set(&rq->nr_iowait, 0); |
7322 | } |
7323 | |
7324 | set_load_weight(&init_task); |
7325 | |
7326 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
7327 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); |
7328 | #endif |
7329 | |
7330 | #ifdef CONFIG_RT_MUTEXES |
7331 | plist_head_init(&init_task.pi_waiters); |
7332 | #endif |
7333 | |
7334 | /* |
7335 | * The boot idle thread does lazy MMU switching as well: |
7336 | */ |
7337 | atomic_inc(&init_mm.mm_count); |
7338 | enter_lazy_tlb(&init_mm, current); |
7339 | |
7340 | /* |
7341 | * Make us the idle thread. Technically, schedule() should not be |
7342 | * called from this thread, however somewhere below it might be, |
7343 | * but because we are the idle thread, we just pick up running again |
7344 | * when this runqueue becomes "idle". |
7345 | */ |
7346 | init_idle(current, smp_processor_id()); |
7347 | |
7348 | calc_load_update = jiffies + LOAD_FREQ; |
7349 | |
7350 | /* |
7351 | * During early bootup we pretend to be a normal task: |
7352 | */ |
7353 | current->sched_class = &fair_sched_class; |
7354 | |
7355 | #ifdef CONFIG_SMP |
7356 | zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); |
7357 | /* May be allocated at isolcpus cmdline parse time */ |
7358 | if (cpu_isolated_map == NULL) |
7359 | zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); |
7360 | idle_thread_set_boot_cpu(); |
7361 | #endif |
7362 | init_sched_fair_class(); |
7363 | |
7364 | scheduler_running = 1; |
7365 | } |
7366 | |
7367 | #ifdef CONFIG_DEBUG_ATOMIC_SLEEP |
7368 | static inline int preempt_count_equals(int preempt_offset) |
7369 | { |
7370 | int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); |
7371 | |
7372 | return (nested == preempt_offset); |
7373 | } |
7374 | |
7375 | void __might_sleep(const char *file, int line, int preempt_offset) |
7376 | { |
7377 | static unsigned long prev_jiffy; /* ratelimiting */ |
7378 | |
7379 | rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ |
7380 | if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || |
7381 | system_state != SYSTEM_RUNNING || oops_in_progress) |
7382 | return; |
7383 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) |
7384 | return; |
7385 | prev_jiffy = jiffies; |
7386 | |
7387 | printk(KERN_ERR |
7388 | "BUG: sleeping function called from invalid context at %s:%d\n", |
7389 | file, line); |
7390 | printk(KERN_ERR |
7391 | "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", |
7392 | in_atomic(), irqs_disabled(), |
7393 | current->pid, current->comm); |
7394 | |
7395 | debug_show_held_locks(current); |
7396 | if (irqs_disabled()) |
7397 | print_irqtrace_events(current); |
7398 | dump_stack(); |
7399 | } |
7400 | EXPORT_SYMBOL(__might_sleep); |
7401 | #endif |
7402 | |
7403 | #ifdef CONFIG_MAGIC_SYSRQ |
7404 | static void normalize_task(struct rq *rq, struct task_struct *p) |
7405 | { |
7406 | const struct sched_class *prev_class = p->sched_class; |
7407 | int old_prio = p->prio; |
7408 | int on_rq; |
7409 | |
7410 | on_rq = p->on_rq; |
7411 | if (on_rq) |
7412 | dequeue_task(rq, p, 0); |
7413 | __setscheduler(rq, p, SCHED_NORMAL, 0); |
7414 | if (on_rq) { |
7415 | enqueue_task(rq, p, 0); |
7416 | resched_task(rq->curr); |
7417 | } |
7418 | |
7419 | check_class_changed(rq, p, prev_class, old_prio); |
7420 | } |
7421 | |
7422 | void normalize_rt_tasks(void) |
7423 | { |
7424 | struct task_struct *g, *p; |
7425 | unsigned long flags; |
7426 | struct rq *rq; |
7427 | |
7428 | read_lock_irqsave(&tasklist_lock, flags); |
7429 | do_each_thread(g, p) { |
7430 | /* |
7431 | * Only normalize user tasks: |
7432 | */ |
7433 | if (!p->mm) |
7434 | continue; |
7435 | |
7436 | p->se.exec_start = 0; |
7437 | #ifdef CONFIG_SCHEDSTATS |
7438 | p->se.statistics.wait_start = 0; |
7439 | p->se.statistics.sleep_start = 0; |
7440 | p->se.statistics.block_start = 0; |
7441 | #endif |
7442 | |
7443 | if (!rt_task(p)) { |
7444 | /* |
7445 | * Renice negative nice level userspace |
7446 | * tasks back to 0: |
7447 | */ |
7448 | if (TASK_NICE(p) < 0 && p->mm) |
7449 | set_user_nice(p, 0); |
7450 | continue; |
7451 | } |
7452 | |
7453 | raw_spin_lock(&p->pi_lock); |
7454 | rq = __task_rq_lock(p); |
7455 | |
7456 | normalize_task(rq, p); |
7457 | |
7458 | __task_rq_unlock(rq); |
7459 | raw_spin_unlock(&p->pi_lock); |
7460 | } while_each_thread(g, p); |
7461 | |
7462 | read_unlock_irqrestore(&tasklist_lock, flags); |
7463 | } |
7464 | |
7465 | #endif /* CONFIG_MAGIC_SYSRQ */ |
7466 | |
7467 | #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) |
7468 | /* |
7469 | * These functions are only useful for the IA64 MCA handling, or kdb. |
7470 | * |
7471 | * They can only be called when the whole system has been |
7472 | * stopped - every CPU needs to be quiescent, and no scheduling |
7473 | * activity can take place. Using them for anything else would |
7474 | * be a serious bug, and as a result, they aren't even visible |
7475 | * under any other configuration. |
7476 | */ |
7477 | |
7478 | /** |
7479 | * curr_task - return the current task for a given cpu. |
7480 | * @cpu: the processor in question. |
7481 | * |
7482 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
7483 | */ |
7484 | struct task_struct *curr_task(int cpu) |
7485 | { |
7486 | return cpu_curr(cpu); |
7487 | } |
7488 | |
7489 | #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ |
7490 | |
7491 | #ifdef CONFIG_IA64 |
7492 | /** |
7493 | * set_curr_task - set the current task for a given cpu. |
7494 | * @cpu: the processor in question. |
7495 | * @p: the task pointer to set. |
7496 | * |
7497 | * Description: This function must only be used when non-maskable interrupts |
7498 | * are serviced on a separate stack. It allows the architecture to switch the |
7499 | * notion of the current task on a cpu in a non-blocking manner. This function |
7500 | * must be called with all CPU's synchronized, and interrupts disabled, the |
7501 | * and caller must save the original value of the current task (see |
7502 | * curr_task() above) and restore that value before reenabling interrupts and |
7503 | * re-starting the system. |
7504 | * |
7505 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
7506 | */ |
7507 | void set_curr_task(int cpu, struct task_struct *p) |
7508 | { |
7509 | cpu_curr(cpu) = p; |
7510 | } |
7511 | |
7512 | #endif |
7513 | |
7514 | #ifdef CONFIG_CGROUP_SCHED |
7515 | /* task_group_lock serializes the addition/removal of task groups */ |
7516 | static DEFINE_SPINLOCK(task_group_lock); |
7517 | |
7518 | static void free_sched_group(struct task_group *tg) |
7519 | { |
7520 | free_fair_sched_group(tg); |
7521 | free_rt_sched_group(tg); |
7522 | autogroup_free(tg); |
7523 | kfree(tg); |
7524 | } |
7525 | |
7526 | /* allocate runqueue etc for a new task group */ |
7527 | struct task_group *sched_create_group(struct task_group *parent) |
7528 | { |
7529 | struct task_group *tg; |
7530 | unsigned long flags; |
7531 | |
7532 | tg = kzalloc(sizeof(*tg), GFP_KERNEL); |
7533 | if (!tg) |
7534 | return ERR_PTR(-ENOMEM); |
7535 | |
7536 | if (!alloc_fair_sched_group(tg, parent)) |
7537 | goto err; |
7538 | |
7539 | if (!alloc_rt_sched_group(tg, parent)) |
7540 | goto err; |
7541 | |
7542 | spin_lock_irqsave(&task_group_lock, flags); |
7543 | list_add_rcu(&tg->list, &task_groups); |
7544 | |
7545 | WARN_ON(!parent); /* root should already exist */ |
7546 | |
7547 | tg->parent = parent; |
7548 | INIT_LIST_HEAD(&tg->children); |
7549 | list_add_rcu(&tg->siblings, &parent->children); |
7550 | spin_unlock_irqrestore(&task_group_lock, flags); |
7551 | |
7552 | return tg; |
7553 | |
7554 | err: |
7555 | free_sched_group(tg); |
7556 | return ERR_PTR(-ENOMEM); |
7557 | } |
7558 | |
7559 | /* rcu callback to free various structures associated with a task group */ |
7560 | static void free_sched_group_rcu(struct rcu_head *rhp) |
7561 | { |
7562 | /* now it should be safe to free those cfs_rqs */ |
7563 | free_sched_group(container_of(rhp, struct task_group, rcu)); |
7564 | } |
7565 | |
7566 | /* Destroy runqueue etc associated with a task group */ |
7567 | void sched_destroy_group(struct task_group *tg) |
7568 | { |
7569 | unsigned long flags; |
7570 | int i; |
7571 | |
7572 | /* end participation in shares distribution */ |
7573 | for_each_possible_cpu(i) |
7574 | unregister_fair_sched_group(tg, i); |
7575 | |
7576 | spin_lock_irqsave(&task_group_lock, flags); |
7577 | list_del_rcu(&tg->list); |
7578 | list_del_rcu(&tg->siblings); |
7579 | spin_unlock_irqrestore(&task_group_lock, flags); |
7580 | |
7581 | /* wait for possible concurrent references to cfs_rqs complete */ |
7582 | call_rcu(&tg->rcu, free_sched_group_rcu); |
7583 | } |
7584 | |
7585 | /* change task's runqueue when it moves between groups. |
7586 | * The caller of this function should have put the task in its new group |
7587 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to |
7588 | * reflect its new group. |
7589 | */ |
7590 | void sched_move_task(struct task_struct *tsk) |
7591 | { |
7592 | int on_rq, running; |
7593 | unsigned long flags; |
7594 | struct rq *rq; |
7595 | |
7596 | rq = task_rq_lock(tsk, &flags); |
7597 | |
7598 | running = task_current(rq, tsk); |
7599 | on_rq = tsk->on_rq; |
7600 | |
7601 | if (on_rq) |
7602 | dequeue_task(rq, tsk, 0); |
7603 | if (unlikely(running)) |
7604 | tsk->sched_class->put_prev_task(rq, tsk); |
7605 | |
7606 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7607 | if (tsk->sched_class->task_move_group) |
7608 | tsk->sched_class->task_move_group(tsk, on_rq); |
7609 | else |
7610 | #endif |
7611 | set_task_rq(tsk, task_cpu(tsk)); |
7612 | |
7613 | if (unlikely(running)) |
7614 | tsk->sched_class->set_curr_task(rq); |
7615 | if (on_rq) |
7616 | enqueue_task(rq, tsk, 0); |
7617 | |
7618 | task_rq_unlock(rq, tsk, &flags); |
7619 | } |
7620 | #endif /* CONFIG_CGROUP_SCHED */ |
7621 | |
7622 | #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH) |
7623 | static unsigned long to_ratio(u64 period, u64 runtime) |
7624 | { |
7625 | if (runtime == RUNTIME_INF) |
7626 | return 1ULL << 20; |
7627 | |
7628 | return div64_u64(runtime << 20, period); |
7629 | } |
7630 | #endif |
7631 | |
7632 | #ifdef CONFIG_RT_GROUP_SCHED |
7633 | /* |
7634 | * Ensure that the real time constraints are schedulable. |
7635 | */ |
7636 | static DEFINE_MUTEX(rt_constraints_mutex); |
7637 | |
7638 | /* Must be called with tasklist_lock held */ |
7639 | static inline int tg_has_rt_tasks(struct task_group *tg) |
7640 | { |
7641 | struct task_struct *g, *p; |
7642 | |
7643 | do_each_thread(g, p) { |
7644 | if (rt_task(p) && task_rq(p)->rt.tg == tg) |
7645 | return 1; |
7646 | } while_each_thread(g, p); |
7647 | |
7648 | return 0; |
7649 | } |
7650 | |
7651 | struct rt_schedulable_data { |
7652 | struct task_group *tg; |
7653 | u64 rt_period; |
7654 | u64 rt_runtime; |
7655 | }; |
7656 | |
7657 | static int tg_rt_schedulable(struct task_group *tg, void *data) |
7658 | { |
7659 | struct rt_schedulable_data *d = data; |
7660 | struct task_group *child; |
7661 | unsigned long total, sum = 0; |
7662 | u64 period, runtime; |
7663 | |
7664 | period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
7665 | runtime = tg->rt_bandwidth.rt_runtime; |
7666 | |
7667 | if (tg == d->tg) { |
7668 | period = d->rt_period; |
7669 | runtime = d->rt_runtime; |
7670 | } |
7671 | |
7672 | /* |
7673 | * Cannot have more runtime than the period. |
7674 | */ |
7675 | if (runtime > period && runtime != RUNTIME_INF) |
7676 | return -EINVAL; |
7677 | |
7678 | /* |
7679 | * Ensure we don't starve existing RT tasks. |
7680 | */ |
7681 | if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) |
7682 | return -EBUSY; |
7683 | |
7684 | total = to_ratio(period, runtime); |
7685 | |
7686 | /* |
7687 | * Nobody can have more than the global setting allows. |
7688 | */ |
7689 | if (total > to_ratio(global_rt_period(), global_rt_runtime())) |
7690 | return -EINVAL; |
7691 | |
7692 | /* |
7693 | * The sum of our children's runtime should not exceed our own. |
7694 | */ |
7695 | list_for_each_entry_rcu(child, &tg->children, siblings) { |
7696 | period = ktime_to_ns(child->rt_bandwidth.rt_period); |
7697 | runtime = child->rt_bandwidth.rt_runtime; |
7698 | |
7699 | if (child == d->tg) { |
7700 | period = d->rt_period; |
7701 | runtime = d->rt_runtime; |
7702 | } |
7703 | |
7704 | sum += to_ratio(period, runtime); |
7705 | } |
7706 | |
7707 | if (sum > total) |
7708 | return -EINVAL; |
7709 | |
7710 | return 0; |
7711 | } |
7712 | |
7713 | static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) |
7714 | { |
7715 | int ret; |
7716 | |
7717 | struct rt_schedulable_data data = { |
7718 | .tg = tg, |
7719 | .rt_period = period, |
7720 | .rt_runtime = runtime, |
7721 | }; |
7722 | |
7723 | rcu_read_lock(); |
7724 | ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); |
7725 | rcu_read_unlock(); |
7726 | |
7727 | return ret; |
7728 | } |
7729 | |
7730 | static int tg_set_rt_bandwidth(struct task_group *tg, |
7731 | u64 rt_period, u64 rt_runtime) |
7732 | { |
7733 | int i, err = 0; |
7734 | |
7735 | mutex_lock(&rt_constraints_mutex); |
7736 | read_lock(&tasklist_lock); |
7737 | err = __rt_schedulable(tg, rt_period, rt_runtime); |
7738 | if (err) |
7739 | goto unlock; |
7740 | |
7741 | raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
7742 | tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); |
7743 | tg->rt_bandwidth.rt_runtime = rt_runtime; |
7744 | |
7745 | for_each_possible_cpu(i) { |
7746 | struct rt_rq *rt_rq = tg->rt_rq[i]; |
7747 | |
7748 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
7749 | rt_rq->rt_runtime = rt_runtime; |
7750 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
7751 | } |
7752 | raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
7753 | unlock: |
7754 | read_unlock(&tasklist_lock); |
7755 | mutex_unlock(&rt_constraints_mutex); |
7756 | |
7757 | return err; |
7758 | } |
7759 | |
7760 | int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) |
7761 | { |
7762 | u64 rt_runtime, rt_period; |
7763 | |
7764 | rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
7765 | rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; |
7766 | if (rt_runtime_us < 0) |
7767 | rt_runtime = RUNTIME_INF; |
7768 | |
7769 | return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); |
7770 | } |
7771 | |
7772 | long sched_group_rt_runtime(struct task_group *tg) |
7773 | { |
7774 | u64 rt_runtime_us; |
7775 | |
7776 | if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) |
7777 | return -1; |
7778 | |
7779 | rt_runtime_us = tg->rt_bandwidth.rt_runtime; |
7780 | do_div(rt_runtime_us, NSEC_PER_USEC); |
7781 | return rt_runtime_us; |
7782 | } |
7783 | |
7784 | int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) |
7785 | { |
7786 | u64 rt_runtime, rt_period; |
7787 | |
7788 | rt_period = (u64)rt_period_us * NSEC_PER_USEC; |
7789 | rt_runtime = tg->rt_bandwidth.rt_runtime; |
7790 | |
7791 | if (rt_period == 0) |
7792 | return -EINVAL; |
7793 | |
7794 | return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); |
7795 | } |
7796 | |
7797 | long sched_group_rt_period(struct task_group *tg) |
7798 | { |
7799 | u64 rt_period_us; |
7800 | |
7801 | rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); |
7802 | do_div(rt_period_us, NSEC_PER_USEC); |
7803 | return rt_period_us; |
7804 | } |
7805 | |
7806 | static int sched_rt_global_constraints(void) |
7807 | { |
7808 | u64 runtime, period; |
7809 | int ret = 0; |
7810 | |
7811 | if (sysctl_sched_rt_period <= 0) |
7812 | return -EINVAL; |
7813 | |
7814 | runtime = global_rt_runtime(); |
7815 | period = global_rt_period(); |
7816 | |
7817 | /* |
7818 | * Sanity check on the sysctl variables. |
7819 | */ |
7820 | if (runtime > period && runtime != RUNTIME_INF) |
7821 | return -EINVAL; |
7822 | |
7823 | mutex_lock(&rt_constraints_mutex); |
7824 | read_lock(&tasklist_lock); |
7825 | ret = __rt_schedulable(NULL, 0, 0); |
7826 | read_unlock(&tasklist_lock); |
7827 | mutex_unlock(&rt_constraints_mutex); |
7828 | |
7829 | return ret; |
7830 | } |
7831 | |
7832 | int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) |
7833 | { |
7834 | /* Don't accept realtime tasks when there is no way for them to run */ |
7835 | if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) |
7836 | return 0; |
7837 | |
7838 | return 1; |
7839 | } |
7840 | |
7841 | #else /* !CONFIG_RT_GROUP_SCHED */ |
7842 | static int sched_rt_global_constraints(void) |
7843 | { |
7844 | unsigned long flags; |
7845 | int i; |
7846 | |
7847 | if (sysctl_sched_rt_period <= 0) |
7848 | return -EINVAL; |
7849 | |
7850 | /* |
7851 | * There's always some RT tasks in the root group |
7852 | * -- migration, kstopmachine etc.. |
7853 | */ |
7854 | if (sysctl_sched_rt_runtime == 0) |
7855 | return -EBUSY; |
7856 | |
7857 | raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); |
7858 | for_each_possible_cpu(i) { |
7859 | struct rt_rq *rt_rq = &cpu_rq(i)->rt; |
7860 | |
7861 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
7862 | rt_rq->rt_runtime = global_rt_runtime(); |
7863 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
7864 | } |
7865 | raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); |
7866 | |
7867 | return 0; |
7868 | } |
7869 | #endif /* CONFIG_RT_GROUP_SCHED */ |
7870 | |
7871 | int sched_rt_handler(struct ctl_table *table, int write, |
7872 | void __user *buffer, size_t *lenp, |
7873 | loff_t *ppos) |
7874 | { |
7875 | int ret; |
7876 | int old_period, old_runtime; |
7877 | static DEFINE_MUTEX(mutex); |
7878 | |
7879 | mutex_lock(&mutex); |
7880 | old_period = sysctl_sched_rt_period; |
7881 | old_runtime = sysctl_sched_rt_runtime; |
7882 | |
7883 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
7884 | |
7885 | if (!ret && write) { |
7886 | ret = sched_rt_global_constraints(); |
7887 | if (ret) { |
7888 | sysctl_sched_rt_period = old_period; |
7889 | sysctl_sched_rt_runtime = old_runtime; |
7890 | } else { |
7891 | def_rt_bandwidth.rt_runtime = global_rt_runtime(); |
7892 | def_rt_bandwidth.rt_period = |
7893 | ns_to_ktime(global_rt_period()); |
7894 | } |
7895 | } |
7896 | mutex_unlock(&mutex); |
7897 | |
7898 | return ret; |
7899 | } |
7900 | |
7901 | #ifdef CONFIG_CGROUP_SCHED |
7902 | |
7903 | /* return corresponding task_group object of a cgroup */ |
7904 | static inline struct task_group *cgroup_tg(struct cgroup *cgrp) |
7905 | { |
7906 | return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), |
7907 | struct task_group, css); |
7908 | } |
7909 | |
7910 | static struct cgroup_subsys_state *cpu_cgroup_create(struct cgroup *cgrp) |
7911 | { |
7912 | struct task_group *tg, *parent; |
7913 | |
7914 | if (!cgrp->parent) { |
7915 | /* This is early initialization for the top cgroup */ |
7916 | return &root_task_group.css; |
7917 | } |
7918 | |
7919 | parent = cgroup_tg(cgrp->parent); |
7920 | tg = sched_create_group(parent); |
7921 | if (IS_ERR(tg)) |
7922 | return ERR_PTR(-ENOMEM); |
7923 | |
7924 | return &tg->css; |
7925 | } |
7926 | |
7927 | static void cpu_cgroup_destroy(struct cgroup *cgrp) |
7928 | { |
7929 | struct task_group *tg = cgroup_tg(cgrp); |
7930 | |
7931 | sched_destroy_group(tg); |
7932 | } |
7933 | |
7934 | static int cpu_cgroup_can_attach(struct cgroup *cgrp, |
7935 | struct cgroup_taskset *tset) |
7936 | { |
7937 | struct task_struct *task; |
7938 | |
7939 | cgroup_taskset_for_each(task, cgrp, tset) { |
7940 | #ifdef CONFIG_RT_GROUP_SCHED |
7941 | if (!sched_rt_can_attach(cgroup_tg(cgrp), task)) |
7942 | return -EINVAL; |
7943 | #else |
7944 | /* We don't support RT-tasks being in separate groups */ |
7945 | if (task->sched_class != &fair_sched_class) |
7946 | return -EINVAL; |
7947 | #endif |
7948 | } |
7949 | return 0; |
7950 | } |
7951 | |
7952 | static void cpu_cgroup_attach(struct cgroup *cgrp, |
7953 | struct cgroup_taskset *tset) |
7954 | { |
7955 | struct task_struct *task; |
7956 | |
7957 | cgroup_taskset_for_each(task, cgrp, tset) |
7958 | sched_move_task(task); |
7959 | } |
7960 | |
7961 | static void |
7962 | cpu_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp, |
7963 | struct task_struct *task) |
7964 | { |
7965 | /* |
7966 | * cgroup_exit() is called in the copy_process() failure path. |
7967 | * Ignore this case since the task hasn't ran yet, this avoids |
7968 | * trying to poke a half freed task state from generic code. |
7969 | */ |
7970 | if (!(task->flags & PF_EXITING)) |
7971 | return; |
7972 | |
7973 | sched_move_task(task); |
7974 | } |
7975 | |
7976 | #ifdef CONFIG_FAIR_GROUP_SCHED |
7977 | static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype, |
7978 | u64 shareval) |
7979 | { |
7980 | return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval)); |
7981 | } |
7982 | |
7983 | static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) |
7984 | { |
7985 | struct task_group *tg = cgroup_tg(cgrp); |
7986 | |
7987 | return (u64) scale_load_down(tg->shares); |
7988 | } |
7989 | |
7990 | #ifdef CONFIG_CFS_BANDWIDTH |
7991 | static DEFINE_MUTEX(cfs_constraints_mutex); |
7992 | |
7993 | const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ |
7994 | const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ |
7995 | |
7996 | static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); |
7997 | |
7998 | static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) |
7999 | { |
8000 | int i, ret = 0, runtime_enabled, runtime_was_enabled; |
8001 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
8002 | |
8003 | if (tg == &root_task_group) |
8004 | return -EINVAL; |
8005 | |
8006 | /* |
8007 | * Ensure we have at some amount of bandwidth every period. This is |
8008 | * to prevent reaching a state of large arrears when throttled via |
8009 | * entity_tick() resulting in prolonged exit starvation. |
8010 | */ |
8011 | if (quota < min_cfs_quota_period || period < min_cfs_quota_period) |
8012 | return -EINVAL; |
8013 | |
8014 | /* |
8015 | * Likewise, bound things on the otherside by preventing insane quota |
8016 | * periods. This also allows us to normalize in computing quota |
8017 | * feasibility. |
8018 | */ |
8019 | if (period > max_cfs_quota_period) |
8020 | return -EINVAL; |
8021 | |
8022 | mutex_lock(&cfs_constraints_mutex); |
8023 | ret = __cfs_schedulable(tg, period, quota); |
8024 | if (ret) |
8025 | goto out_unlock; |
8026 | |
8027 | runtime_enabled = quota != RUNTIME_INF; |
8028 | runtime_was_enabled = cfs_b->quota != RUNTIME_INF; |
8029 | account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled); |
8030 | raw_spin_lock_irq(&cfs_b->lock); |
8031 | cfs_b->period = ns_to_ktime(period); |
8032 | cfs_b->quota = quota; |
8033 | |
8034 | __refill_cfs_bandwidth_runtime(cfs_b); |
8035 | /* restart the period timer (if active) to handle new period expiry */ |
8036 | if (runtime_enabled && cfs_b->timer_active) { |
8037 | /* force a reprogram */ |
8038 | cfs_b->timer_active = 0; |
8039 | __start_cfs_bandwidth(cfs_b); |
8040 | } |
8041 | raw_spin_unlock_irq(&cfs_b->lock); |
8042 | |
8043 | for_each_possible_cpu(i) { |
8044 | struct cfs_rq *cfs_rq = tg->cfs_rq[i]; |
8045 | struct rq *rq = cfs_rq->rq; |
8046 | |
8047 | raw_spin_lock_irq(&rq->lock); |
8048 | cfs_rq->runtime_enabled = runtime_enabled; |
8049 | cfs_rq->runtime_remaining = 0; |
8050 | |
8051 | if (cfs_rq->throttled) |
8052 | unthrottle_cfs_rq(cfs_rq); |
8053 | raw_spin_unlock_irq(&rq->lock); |
8054 | } |
8055 | out_unlock: |
8056 | mutex_unlock(&cfs_constraints_mutex); |
8057 | |
8058 | return ret; |
8059 | } |
8060 | |
8061 | int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) |
8062 | { |
8063 | u64 quota, period; |
8064 | |
8065 | period = ktime_to_ns(tg->cfs_bandwidth.period); |
8066 | if (cfs_quota_us < 0) |
8067 | quota = RUNTIME_INF; |
8068 | else |
8069 | quota = (u64)cfs_quota_us * NSEC_PER_USEC; |
8070 | |
8071 | return tg_set_cfs_bandwidth(tg, period, quota); |
8072 | } |
8073 | |
8074 | long tg_get_cfs_quota(struct task_group *tg) |
8075 | { |
8076 | u64 quota_us; |
8077 | |
8078 | if (tg->cfs_bandwidth.quota == RUNTIME_INF) |
8079 | return -1; |
8080 | |
8081 | quota_us = tg->cfs_bandwidth.quota; |
8082 | do_div(quota_us, NSEC_PER_USEC); |
8083 | |
8084 | return quota_us; |
8085 | } |
8086 | |
8087 | int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) |
8088 | { |
8089 | u64 quota, period; |
8090 | |
8091 | period = (u64)cfs_period_us * NSEC_PER_USEC; |
8092 | quota = tg->cfs_bandwidth.quota; |
8093 | |
8094 | return tg_set_cfs_bandwidth(tg, period, quota); |
8095 | } |
8096 | |
8097 | long tg_get_cfs_period(struct task_group *tg) |
8098 | { |
8099 | u64 cfs_period_us; |
8100 | |
8101 | cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); |
8102 | do_div(cfs_period_us, NSEC_PER_USEC); |
8103 | |
8104 | return cfs_period_us; |
8105 | } |
8106 | |
8107 | static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft) |
8108 | { |
8109 | return tg_get_cfs_quota(cgroup_tg(cgrp)); |
8110 | } |
8111 | |
8112 | static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype, |
8113 | s64 cfs_quota_us) |
8114 | { |
8115 | return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us); |
8116 | } |
8117 | |
8118 | static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft) |
8119 | { |
8120 | return tg_get_cfs_period(cgroup_tg(cgrp)); |
8121 | } |
8122 | |
8123 | static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype, |
8124 | u64 cfs_period_us) |
8125 | { |
8126 | return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us); |
8127 | } |
8128 | |
8129 | struct cfs_schedulable_data { |
8130 | struct task_group *tg; |
8131 | u64 period, quota; |
8132 | }; |
8133 | |
8134 | /* |
8135 | * normalize group quota/period to be quota/max_period |
8136 | * note: units are usecs |
8137 | */ |
8138 | static u64 normalize_cfs_quota(struct task_group *tg, |
8139 | struct cfs_schedulable_data *d) |
8140 | { |
8141 | u64 quota, period; |
8142 | |
8143 | if (tg == d->tg) { |
8144 | period = d->period; |
8145 | quota = d->quota; |
8146 | } else { |
8147 | period = tg_get_cfs_period(tg); |
8148 | quota = tg_get_cfs_quota(tg); |
8149 | } |
8150 | |
8151 | /* note: these should typically be equivalent */ |
8152 | if (quota == RUNTIME_INF || quota == -1) |
8153 | return RUNTIME_INF; |
8154 | |
8155 | return to_ratio(period, quota); |
8156 | } |
8157 | |
8158 | static int tg_cfs_schedulable_down(struct task_group *tg, void *data) |
8159 | { |
8160 | struct cfs_schedulable_data *d = data; |
8161 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
8162 | s64 quota = 0, parent_quota = -1; |
8163 | |
8164 | if (!tg->parent) { |
8165 | quota = RUNTIME_INF; |
8166 | } else { |
8167 | struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; |
8168 | |
8169 | quota = normalize_cfs_quota(tg, d); |
8170 | parent_quota = parent_b->hierarchal_quota; |
8171 | |
8172 | /* |
8173 | * ensure max(child_quota) <= parent_quota, inherit when no |
8174 | * limit is set |
8175 | */ |
8176 | if (quota == RUNTIME_INF) |
8177 | quota = parent_quota; |
8178 | else if (parent_quota != RUNTIME_INF && quota > parent_quota) |
8179 | return -EINVAL; |
8180 | } |
8181 | cfs_b->hierarchal_quota = quota; |
8182 | |
8183 | return 0; |
8184 | } |
8185 | |
8186 | static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) |
8187 | { |
8188 | int ret; |
8189 | struct cfs_schedulable_data data = { |
8190 | .tg = tg, |
8191 | .period = period, |
8192 | .quota = quota, |
8193 | }; |
8194 | |
8195 | if (quota != RUNTIME_INF) { |
8196 | do_div(data.period, NSEC_PER_USEC); |
8197 | do_div(data.quota, NSEC_PER_USEC); |
8198 | } |
8199 | |
8200 | rcu_read_lock(); |
8201 | ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); |
8202 | rcu_read_unlock(); |
8203 | |
8204 | return ret; |
8205 | } |
8206 | |
8207 | static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft, |
8208 | struct cgroup_map_cb *cb) |
8209 | { |
8210 | struct task_group *tg = cgroup_tg(cgrp); |
8211 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
8212 | |
8213 | cb->fill(cb, "nr_periods", cfs_b->nr_periods); |
8214 | cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); |
8215 | cb->fill(cb, "throttled_time", cfs_b->throttled_time); |
8216 | |
8217 | return 0; |
8218 | } |
8219 | #endif /* CONFIG_CFS_BANDWIDTH */ |
8220 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
8221 | |
8222 | #ifdef CONFIG_RT_GROUP_SCHED |
8223 | static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, |
8224 | s64 val) |
8225 | { |
8226 | return sched_group_set_rt_runtime(cgroup_tg(cgrp), val); |
8227 | } |
8228 | |
8229 | static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft) |
8230 | { |
8231 | return sched_group_rt_runtime(cgroup_tg(cgrp)); |
8232 | } |
8233 | |
8234 | static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype, |
8235 | u64 rt_period_us) |
8236 | { |
8237 | return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us); |
8238 | } |
8239 | |
8240 | static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) |
8241 | { |
8242 | return sched_group_rt_period(cgroup_tg(cgrp)); |
8243 | } |
8244 | #endif /* CONFIG_RT_GROUP_SCHED */ |
8245 | |
8246 | static struct cftype cpu_files[] = { |
8247 | #ifdef CONFIG_FAIR_GROUP_SCHED |
8248 | { |
8249 | .name = "shares", |
8250 | .read_u64 = cpu_shares_read_u64, |
8251 | .write_u64 = cpu_shares_write_u64, |
8252 | }, |
8253 | #endif |
8254 | #ifdef CONFIG_CFS_BANDWIDTH |
8255 | { |
8256 | .name = "cfs_quota_us", |
8257 | .read_s64 = cpu_cfs_quota_read_s64, |
8258 | .write_s64 = cpu_cfs_quota_write_s64, |
8259 | }, |
8260 | { |
8261 | .name = "cfs_period_us", |
8262 | .read_u64 = cpu_cfs_period_read_u64, |
8263 | .write_u64 = cpu_cfs_period_write_u64, |
8264 | }, |
8265 | { |
8266 | .name = "stat", |
8267 | .read_map = cpu_stats_show, |
8268 | }, |
8269 | #endif |
8270 | #ifdef CONFIG_RT_GROUP_SCHED |
8271 | { |
8272 | .name = "rt_runtime_us", |
8273 | .read_s64 = cpu_rt_runtime_read, |
8274 | .write_s64 = cpu_rt_runtime_write, |
8275 | }, |
8276 | { |
8277 | .name = "rt_period_us", |
8278 | .read_u64 = cpu_rt_period_read_uint, |
8279 | .write_u64 = cpu_rt_period_write_uint, |
8280 | }, |
8281 | #endif |
8282 | { } /* terminate */ |
8283 | }; |
8284 | |
8285 | struct cgroup_subsys cpu_cgroup_subsys = { |
8286 | .name = "cpu", |
8287 | .create = cpu_cgroup_create, |
8288 | .destroy = cpu_cgroup_destroy, |
8289 | .can_attach = cpu_cgroup_can_attach, |
8290 | .attach = cpu_cgroup_attach, |
8291 | .exit = cpu_cgroup_exit, |
8292 | .subsys_id = cpu_cgroup_subsys_id, |
8293 | .base_cftypes = cpu_files, |
8294 | .early_init = 1, |
8295 | }; |
8296 | |
8297 | #endif /* CONFIG_CGROUP_SCHED */ |
8298 | |
8299 | #ifdef CONFIG_CGROUP_CPUACCT |
8300 | |
8301 | /* |
8302 | * CPU accounting code for task groups. |
8303 | * |
8304 | * Based on the work by Paul Menage (menage@google.com) and Balbir Singh |
8305 | * (balbir@in.ibm.com). |
8306 | */ |
8307 | |
8308 | /* create a new cpu accounting group */ |
8309 | static struct cgroup_subsys_state *cpuacct_create(struct cgroup *cgrp) |
8310 | { |
8311 | struct cpuacct *ca; |
8312 | |
8313 | if (!cgrp->parent) |
8314 | return &root_cpuacct.css; |
8315 | |
8316 | ca = kzalloc(sizeof(*ca), GFP_KERNEL); |
8317 | if (!ca) |
8318 | goto out; |
8319 | |
8320 | ca->cpuusage = alloc_percpu(u64); |
8321 | if (!ca->cpuusage) |
8322 | goto out_free_ca; |
8323 | |
8324 | ca->cpustat = alloc_percpu(struct kernel_cpustat); |
8325 | if (!ca->cpustat) |
8326 | goto out_free_cpuusage; |
8327 | |
8328 | return &ca->css; |
8329 | |
8330 | out_free_cpuusage: |
8331 | free_percpu(ca->cpuusage); |
8332 | out_free_ca: |
8333 | kfree(ca); |
8334 | out: |
8335 | return ERR_PTR(-ENOMEM); |
8336 | } |
8337 | |
8338 | /* destroy an existing cpu accounting group */ |
8339 | static void cpuacct_destroy(struct cgroup *cgrp) |
8340 | { |
8341 | struct cpuacct *ca = cgroup_ca(cgrp); |
8342 | |
8343 | free_percpu(ca->cpustat); |
8344 | free_percpu(ca->cpuusage); |
8345 | kfree(ca); |
8346 | } |
8347 | |
8348 | static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu) |
8349 | { |
8350 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
8351 | u64 data; |
8352 | |
8353 | #ifndef CONFIG_64BIT |
8354 | /* |
8355 | * Take rq->lock to make 64-bit read safe on 32-bit platforms. |
8356 | */ |
8357 | raw_spin_lock_irq(&cpu_rq(cpu)->lock); |
8358 | data = *cpuusage; |
8359 | raw_spin_unlock_irq(&cpu_rq(cpu)->lock); |
8360 | #else |
8361 | data = *cpuusage; |
8362 | #endif |
8363 | |
8364 | return data; |
8365 | } |
8366 | |
8367 | static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val) |
8368 | { |
8369 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
8370 | |
8371 | #ifndef CONFIG_64BIT |
8372 | /* |
8373 | * Take rq->lock to make 64-bit write safe on 32-bit platforms. |
8374 | */ |
8375 | raw_spin_lock_irq(&cpu_rq(cpu)->lock); |
8376 | *cpuusage = val; |
8377 | raw_spin_unlock_irq(&cpu_rq(cpu)->lock); |
8378 | #else |
8379 | *cpuusage = val; |
8380 | #endif |
8381 | } |
8382 | |
8383 | /* return total cpu usage (in nanoseconds) of a group */ |
8384 | static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft) |
8385 | { |
8386 | struct cpuacct *ca = cgroup_ca(cgrp); |
8387 | u64 totalcpuusage = 0; |
8388 | int i; |
8389 | |
8390 | for_each_present_cpu(i) |
8391 | totalcpuusage += cpuacct_cpuusage_read(ca, i); |
8392 | |
8393 | return totalcpuusage; |
8394 | } |
8395 | |
8396 | static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype, |
8397 | u64 reset) |
8398 | { |
8399 | struct cpuacct *ca = cgroup_ca(cgrp); |
8400 | int err = 0; |
8401 | int i; |
8402 | |
8403 | if (reset) { |
8404 | err = -EINVAL; |
8405 | goto out; |
8406 | } |
8407 | |
8408 | for_each_present_cpu(i) |
8409 | cpuacct_cpuusage_write(ca, i, 0); |
8410 | |
8411 | out: |
8412 | return err; |
8413 | } |
8414 | |
8415 | static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft, |
8416 | struct seq_file *m) |
8417 | { |
8418 | struct cpuacct *ca = cgroup_ca(cgroup); |
8419 | u64 percpu; |
8420 | int i; |
8421 | |
8422 | for_each_present_cpu(i) { |
8423 | percpu = cpuacct_cpuusage_read(ca, i); |
8424 | seq_printf(m, "%llu ", (unsigned long long) percpu); |
8425 | } |
8426 | seq_printf(m, "\n"); |
8427 | return 0; |
8428 | } |
8429 | |
8430 | static const char *cpuacct_stat_desc[] = { |
8431 | [CPUACCT_STAT_USER] = "user", |
8432 | [CPUACCT_STAT_SYSTEM] = "system", |
8433 | }; |
8434 | |
8435 | static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft, |
8436 | struct cgroup_map_cb *cb) |
8437 | { |
8438 | struct cpuacct *ca = cgroup_ca(cgrp); |
8439 | int cpu; |
8440 | s64 val = 0; |
8441 | |
8442 | for_each_online_cpu(cpu) { |
8443 | struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); |
8444 | val += kcpustat->cpustat[CPUTIME_USER]; |
8445 | val += kcpustat->cpustat[CPUTIME_NICE]; |
8446 | } |
8447 | val = cputime64_to_clock_t(val); |
8448 | cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val); |
8449 | |
8450 | val = 0; |
8451 | for_each_online_cpu(cpu) { |
8452 | struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu); |
8453 | val += kcpustat->cpustat[CPUTIME_SYSTEM]; |
8454 | val += kcpustat->cpustat[CPUTIME_IRQ]; |
8455 | val += kcpustat->cpustat[CPUTIME_SOFTIRQ]; |
8456 | } |
8457 | |
8458 | val = cputime64_to_clock_t(val); |
8459 | cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val); |
8460 | |
8461 | return 0; |
8462 | } |
8463 | |
8464 | static struct cftype files[] = { |
8465 | { |
8466 | .name = "usage", |
8467 | .read_u64 = cpuusage_read, |
8468 | .write_u64 = cpuusage_write, |
8469 | }, |
8470 | { |
8471 | .name = "usage_percpu", |
8472 | .read_seq_string = cpuacct_percpu_seq_read, |
8473 | }, |
8474 | { |
8475 | .name = "stat", |
8476 | .read_map = cpuacct_stats_show, |
8477 | }, |
8478 | { } /* terminate */ |
8479 | }; |
8480 | |
8481 | /* |
8482 | * charge this task's execution time to its accounting group. |
8483 | * |
8484 | * called with rq->lock held. |
8485 | */ |
8486 | void cpuacct_charge(struct task_struct *tsk, u64 cputime) |
8487 | { |
8488 | struct cpuacct *ca; |
8489 | int cpu; |
8490 | |
8491 | if (unlikely(!cpuacct_subsys.active)) |
8492 | return; |
8493 | |
8494 | cpu = task_cpu(tsk); |
8495 | |
8496 | rcu_read_lock(); |
8497 | |
8498 | ca = task_ca(tsk); |
8499 | |
8500 | for (; ca; ca = parent_ca(ca)) { |
8501 | u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); |
8502 | *cpuusage += cputime; |
8503 | } |
8504 | |
8505 | rcu_read_unlock(); |
8506 | } |
8507 | |
8508 | struct cgroup_subsys cpuacct_subsys = { |
8509 | .name = "cpuacct", |
8510 | .create = cpuacct_create, |
8511 | .destroy = cpuacct_destroy, |
8512 | .subsys_id = cpuacct_subsys_id, |
8513 | .base_cftypes = files, |
8514 | }; |
8515 | #endif /* CONFIG_CGROUP_CPUACCT */ |
8516 |
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