4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
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
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
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
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>
76 #include <asm/switch_to.h>
78 #include <asm/irq_regs.h>
79 #include <asm/mutex.h>
80 #ifdef CONFIG_PARAVIRT
81 #include <asm/paravirt.h>
85 #include "../workqueue_sched.h"
86 #include "../smpboot.h"
88 #define CREATE_TRACE_POINTS
89 #include <trace/events/sched.h>
91 void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period)
94 ktime_t soft, hard, now;
97 if (hrtimer_active(period_timer))
100 now = hrtimer_cb_get_time(period_timer);
101 hrtimer_forward(period_timer, now, period);
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);
111 DEFINE_MUTEX(sched_domains_mutex);
112 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
114 static void update_rq_clock_task(struct rq *rq, s64 delta);
116 void update_rq_clock(struct rq *rq)
120 if (rq->skip_clock_update > 0)
123 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
125 update_rq_clock_task(rq, delta);
129 * Debugging: various feature bits
132 #define SCHED_FEAT(name, enabled) \
133 (1UL << __SCHED_FEAT_##name) * enabled |
135 const_debug unsigned int sysctl_sched_features =
136 #include "features.h"
141 #ifdef CONFIG_SCHED_DEBUG
142 #define SCHED_FEAT(name, enabled) \
145 static __read_mostly char *sched_feat_names[] = {
146 #include "features.h"
152 static int sched_feat_show(struct seq_file *m, void *v)
156 for (i = 0; i < __SCHED_FEAT_NR; i++) {
157 if (!(sysctl_sched_features & (1UL << i)))
159 seq_printf(m, "%s ", sched_feat_names[i]);
166 #ifdef HAVE_JUMP_LABEL
168 #define jump_label_key__true STATIC_KEY_INIT_TRUE
169 #define jump_label_key__false STATIC_KEY_INIT_FALSE
171 #define SCHED_FEAT(name, enabled) \
172 jump_label_key__##enabled ,
174 struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
175 #include "features.h"
180 static void sched_feat_disable(int i)
182 if (static_key_enabled(&sched_feat_keys[i]))
183 static_key_slow_dec(&sched_feat_keys[i]);
186 static void sched_feat_enable(int i)
188 if (!static_key_enabled(&sched_feat_keys[i]))
189 static_key_slow_inc(&sched_feat_keys[i]);
192 static void sched_feat_disable(int i) { };
193 static void sched_feat_enable(int i) { };
194 #endif /* HAVE_JUMP_LABEL */
197 sched_feat_write(struct file *filp, const char __user *ubuf,
198 size_t cnt, loff_t *ppos)
208 if (copy_from_user(&buf, ubuf, cnt))
214 if (strncmp(cmp, "NO_", 3) == 0) {
219 for (i = 0; i < __SCHED_FEAT_NR; i++) {
220 if (strcmp(cmp, sched_feat_names[i]) == 0) {
222 sysctl_sched_features &= ~(1UL << i);
223 sched_feat_disable(i);
225 sysctl_sched_features |= (1UL << i);
226 sched_feat_enable(i);
232 if (i == __SCHED_FEAT_NR)
240 static int sched_feat_open(struct inode *inode, struct file *filp)
242 return single_open(filp, sched_feat_show, NULL);
245 static const struct file_operations sched_feat_fops = {
246 .open = sched_feat_open,
247 .write = sched_feat_write,
250 .release = single_release,
253 static __init int sched_init_debug(void)
255 debugfs_create_file("sched_features", 0644, NULL, NULL,
260 late_initcall(sched_init_debug);
261 #endif /* CONFIG_SCHED_DEBUG */
264 * Number of tasks to iterate in a single balance run.
265 * Limited because this is done with IRQs disabled.
267 const_debug unsigned int sysctl_sched_nr_migrate = 32;
270 * period over which we average the RT time consumption, measured
275 const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
278 * period over which we measure -rt task cpu usage in us.
281 unsigned int sysctl_sched_rt_period = 1000000;
283 __read_mostly int scheduler_running;
286 * part of the period that we allow rt tasks to run in us.
289 int sysctl_sched_rt_runtime = 950000;
294 * __task_rq_lock - lock the rq @p resides on.
296 static inline struct rq *__task_rq_lock(struct task_struct *p)
301 lockdep_assert_held(&p->pi_lock);
305 raw_spin_lock(&rq->lock);
306 if (likely(rq == task_rq(p)))
308 raw_spin_unlock(&rq->lock);
313 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
315 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
316 __acquires(p->pi_lock)
322 raw_spin_lock_irqsave(&p->pi_lock, *flags);
324 raw_spin_lock(&rq->lock);
325 if (likely(rq == task_rq(p)))
327 raw_spin_unlock(&rq->lock);
328 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
332 static void __task_rq_unlock(struct rq *rq)
335 raw_spin_unlock(&rq->lock);
339 task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
341 __releases(p->pi_lock)
343 raw_spin_unlock(&rq->lock);
344 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
348 * this_rq_lock - lock this runqueue and disable interrupts.
350 static struct rq *this_rq_lock(void)
357 raw_spin_lock(&rq->lock);
362 #ifdef CONFIG_SCHED_HRTICK
364 * Use HR-timers to deliver accurate preemption points.
366 * Its all a bit involved since we cannot program an hrt while holding the
367 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
370 * When we get rescheduled we reprogram the hrtick_timer outside of the
374 static void hrtick_clear(struct rq *rq)
376 if (hrtimer_active(&rq->hrtick_timer))
377 hrtimer_cancel(&rq->hrtick_timer);
381 * High-resolution timer tick.
382 * Runs from hardirq context with interrupts disabled.
384 static enum hrtimer_restart hrtick(struct hrtimer *timer)
386 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
388 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
390 raw_spin_lock(&rq->lock);
392 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
393 raw_spin_unlock(&rq->lock);
395 return HRTIMER_NORESTART;
400 * called from hardirq (IPI) context
402 static void __hrtick_start(void *arg)
406 raw_spin_lock(&rq->lock);
407 hrtimer_restart(&rq->hrtick_timer);
408 rq->hrtick_csd_pending = 0;
409 raw_spin_unlock(&rq->lock);
413 * Called to set the hrtick timer state.
415 * called with rq->lock held and irqs disabled
417 void hrtick_start(struct rq *rq, u64 delay)
419 struct hrtimer *timer = &rq->hrtick_timer;
420 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
422 hrtimer_set_expires(timer, time);
424 if (rq == this_rq()) {
425 hrtimer_restart(timer);
426 } else if (!rq->hrtick_csd_pending) {
427 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
428 rq->hrtick_csd_pending = 1;
433 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
435 int cpu = (int)(long)hcpu;
438 case CPU_UP_CANCELED:
439 case CPU_UP_CANCELED_FROZEN:
440 case CPU_DOWN_PREPARE:
441 case CPU_DOWN_PREPARE_FROZEN:
443 case CPU_DEAD_FROZEN:
444 hrtick_clear(cpu_rq(cpu));
451 static __init void init_hrtick(void)
453 hotcpu_notifier(hotplug_hrtick, 0);
457 * Called to set the hrtick timer state.
459 * called with rq->lock held and irqs disabled
461 void hrtick_start(struct rq *rq, u64 delay)
463 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
464 HRTIMER_MODE_REL_PINNED, 0);
467 static inline void init_hrtick(void)
470 #endif /* CONFIG_SMP */
472 static void init_rq_hrtick(struct rq *rq)
475 rq->hrtick_csd_pending = 0;
477 rq->hrtick_csd.flags = 0;
478 rq->hrtick_csd.func = __hrtick_start;
479 rq->hrtick_csd.info = rq;
482 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
483 rq->hrtick_timer.function = hrtick;
485 #else /* CONFIG_SCHED_HRTICK */
486 static inline void hrtick_clear(struct rq *rq)
490 static inline void init_rq_hrtick(struct rq *rq)
494 static inline void init_hrtick(void)
497 #endif /* CONFIG_SCHED_HRTICK */
500 * resched_task - mark a task 'to be rescheduled now'.
502 * On UP this means the setting of the need_resched flag, on SMP it
503 * might also involve a cross-CPU call to trigger the scheduler on
508 #ifndef tsk_is_polling
509 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
512 void resched_task(struct task_struct *p)
516 assert_raw_spin_locked(&task_rq(p)->lock);
518 if (test_tsk_need_resched(p))
521 set_tsk_need_resched(p);
524 if (cpu == smp_processor_id())
527 /* NEED_RESCHED must be visible before we test polling */
529 if (!tsk_is_polling(p))
530 smp_send_reschedule(cpu);
533 void resched_cpu(int cpu)
535 struct rq *rq = cpu_rq(cpu);
538 if (!raw_spin_trylock_irqsave(&rq->lock, flags))
540 resched_task(cpu_curr(cpu));
541 raw_spin_unlock_irqrestore(&rq->lock, flags);
546 * In the semi idle case, use the nearest busy cpu for migrating timers
547 * from an idle cpu. This is good for power-savings.
549 * We don't do similar optimization for completely idle system, as
550 * selecting an idle cpu will add more delays to the timers than intended
551 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
553 int get_nohz_timer_target(void)
555 int cpu = smp_processor_id();
557 struct sched_domain *sd;
560 for_each_domain(cpu, sd) {
561 for_each_cpu(i, sched_domain_span(sd)) {
573 * When add_timer_on() enqueues a timer into the timer wheel of an
574 * idle CPU then this timer might expire before the next timer event
575 * which is scheduled to wake up that CPU. In case of a completely
576 * idle system the next event might even be infinite time into the
577 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
578 * leaves the inner idle loop so the newly added timer is taken into
579 * account when the CPU goes back to idle and evaluates the timer
580 * wheel for the next timer event.
582 void wake_up_idle_cpu(int cpu)
584 struct rq *rq = cpu_rq(cpu);
586 if (cpu == smp_processor_id())
590 * This is safe, as this function is called with the timer
591 * wheel base lock of (cpu) held. When the CPU is on the way
592 * to idle and has not yet set rq->curr to idle then it will
593 * be serialized on the timer wheel base lock and take the new
594 * timer into account automatically.
596 if (rq->curr != rq->idle)
600 * We can set TIF_RESCHED on the idle task of the other CPU
601 * lockless. The worst case is that the other CPU runs the
602 * idle task through an additional NOOP schedule()
604 set_tsk_need_resched(rq->idle);
606 /* NEED_RESCHED must be visible before we test polling */
608 if (!tsk_is_polling(rq->idle))
609 smp_send_reschedule(cpu);
612 static inline bool got_nohz_idle_kick(void)
614 int cpu = smp_processor_id();
615 return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));
618 #else /* CONFIG_NO_HZ */
620 static inline bool got_nohz_idle_kick(void)
625 #endif /* CONFIG_NO_HZ */
627 void sched_avg_update(struct rq *rq)
629 s64 period = sched_avg_period();
631 while ((s64)(rq->clock - rq->age_stamp) > period) {
633 * Inline assembly required to prevent the compiler
634 * optimising this loop into a divmod call.
635 * See __iter_div_u64_rem() for another example of this.
637 asm("" : "+rm" (rq->age_stamp));
638 rq->age_stamp += period;
643 #else /* !CONFIG_SMP */
644 void resched_task(struct task_struct *p)
646 assert_raw_spin_locked(&task_rq(p)->lock);
647 set_tsk_need_resched(p);
649 #endif /* CONFIG_SMP */
651 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
652 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
654 * Iterate task_group tree rooted at *from, calling @down when first entering a
655 * node and @up when leaving it for the final time.
657 * Caller must hold rcu_lock or sufficient equivalent.
659 int walk_tg_tree_from(struct task_group *from,
660 tg_visitor down, tg_visitor up, void *data)
662 struct task_group *parent, *child;
668 ret = (*down)(parent, data);
671 list_for_each_entry_rcu(child, &parent->children, siblings) {
678 ret = (*up)(parent, data);
679 if (ret || parent == from)
683 parent = parent->parent;
690 int tg_nop(struct task_group *tg, void *data)
696 static void set_load_weight(struct task_struct *p)
698 int prio = p->static_prio - MAX_RT_PRIO;
699 struct load_weight *load = &p->se.load;
702 * SCHED_IDLE tasks get minimal weight:
704 if (p->policy == SCHED_IDLE) {
705 load->weight = scale_load(WEIGHT_IDLEPRIO);
706 load->inv_weight = WMULT_IDLEPRIO;
710 load->weight = scale_load(prio_to_weight[prio]);
711 load->inv_weight = prio_to_wmult[prio];
714 static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
717 sched_info_queued(p);
718 p->sched_class->enqueue_task(rq, p, flags);
721 static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
724 sched_info_dequeued(p);
725 p->sched_class->dequeue_task(rq, p, flags);
728 void activate_task(struct rq *rq, struct task_struct *p, int flags)
730 if (task_contributes_to_load(p))
731 rq->nr_uninterruptible--;
733 enqueue_task(rq, p, flags);
736 void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
738 if (task_contributes_to_load(p))
739 rq->nr_uninterruptible++;
741 dequeue_task(rq, p, flags);
744 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
747 * There are no locks covering percpu hardirq/softirq time.
748 * They are only modified in account_system_vtime, on corresponding CPU
749 * with interrupts disabled. So, writes are safe.
750 * They are read and saved off onto struct rq in update_rq_clock().
751 * This may result in other CPU reading this CPU's irq time and can
752 * race with irq/account_system_vtime on this CPU. We would either get old
753 * or new value with a side effect of accounting a slice of irq time to wrong
754 * task when irq is in progress while we read rq->clock. That is a worthy
755 * compromise in place of having locks on each irq in account_system_time.
757 static DEFINE_PER_CPU(u64, cpu_hardirq_time);
758 static DEFINE_PER_CPU(u64, cpu_softirq_time);
760 static DEFINE_PER_CPU(u64, irq_start_time);
761 static int sched_clock_irqtime;
763 void enable_sched_clock_irqtime(void)
765 sched_clock_irqtime = 1;
768 void disable_sched_clock_irqtime(void)
770 sched_clock_irqtime = 0;
774 static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
776 static inline void irq_time_write_begin(void)
778 __this_cpu_inc(irq_time_seq.sequence);
782 static inline void irq_time_write_end(void)
785 __this_cpu_inc(irq_time_seq.sequence);
788 static inline u64 irq_time_read(int cpu)
794 seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
795 irq_time = per_cpu(cpu_softirq_time, cpu) +
796 per_cpu(cpu_hardirq_time, cpu);
797 } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));
801 #else /* CONFIG_64BIT */
802 static inline void irq_time_write_begin(void)
806 static inline void irq_time_write_end(void)
810 static inline u64 irq_time_read(int cpu)
812 return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
814 #endif /* CONFIG_64BIT */
817 * Called before incrementing preempt_count on {soft,}irq_enter
818 * and before decrementing preempt_count on {soft,}irq_exit.
820 void account_system_vtime(struct task_struct *curr)
826 if (!sched_clock_irqtime)
829 local_irq_save(flags);
831 cpu = smp_processor_id();
832 delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
833 __this_cpu_add(irq_start_time, delta);
835 irq_time_write_begin();
837 * We do not account for softirq time from ksoftirqd here.
838 * We want to continue accounting softirq time to ksoftirqd thread
839 * in that case, so as not to confuse scheduler with a special task
840 * that do not consume any time, but still wants to run.
843 __this_cpu_add(cpu_hardirq_time, delta);
844 else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
845 __this_cpu_add(cpu_softirq_time, delta);
847 irq_time_write_end();
848 local_irq_restore(flags);
850 EXPORT_SYMBOL_GPL(account_system_vtime);
852 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
854 #ifdef CONFIG_PARAVIRT
855 static inline u64 steal_ticks(u64 steal)
857 if (unlikely(steal > NSEC_PER_SEC))
858 return div_u64(steal, TICK_NSEC);
860 return __iter_div_u64_rem(steal, TICK_NSEC, &steal);
864 static void update_rq_clock_task(struct rq *rq, s64 delta)
867 * In theory, the compile should just see 0 here, and optimize out the call
868 * to sched_rt_avg_update. But I don't trust it...
870 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
871 s64 steal = 0, irq_delta = 0;
873 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
874 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
877 * Since irq_time is only updated on {soft,}irq_exit, we might run into
878 * this case when a previous update_rq_clock() happened inside a
881 * When this happens, we stop ->clock_task and only update the
882 * prev_irq_time stamp to account for the part that fit, so that a next
883 * update will consume the rest. This ensures ->clock_task is
886 * It does however cause some slight miss-attribution of {soft,}irq
887 * time, a more accurate solution would be to update the irq_time using
888 * the current rq->clock timestamp, except that would require using
891 if (irq_delta > delta)
894 rq->prev_irq_time += irq_delta;
897 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
898 if (static_key_false((¶virt_steal_rq_enabled))) {
901 steal = paravirt_steal_clock(cpu_of(rq));
902 steal -= rq->prev_steal_time_rq;
904 if (unlikely(steal > delta))
907 st = steal_ticks(steal);
908 steal = st * TICK_NSEC;
910 rq->prev_steal_time_rq += steal;
916 rq->clock_task += delta;
918 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
919 if ((irq_delta + steal) && sched_feat(NONTASK_POWER))
920 sched_rt_avg_update(rq, irq_delta + steal);
924 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
925 static int irqtime_account_hi_update(void)
927 u64 *cpustat = kcpustat_this_cpu->cpustat;
932 local_irq_save(flags);
933 latest_ns = this_cpu_read(cpu_hardirq_time);
934 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ])
936 local_irq_restore(flags);
940 static int irqtime_account_si_update(void)
942 u64 *cpustat = kcpustat_this_cpu->cpustat;
947 local_irq_save(flags);
948 latest_ns = this_cpu_read(cpu_softirq_time);
949 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ])
951 local_irq_restore(flags);
955 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
957 #define sched_clock_irqtime (0)
961 void sched_set_stop_task(int cpu, struct task_struct *stop)
963 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
964 struct task_struct *old_stop = cpu_rq(cpu)->stop;
968 * Make it appear like a SCHED_FIFO task, its something
969 * userspace knows about and won't get confused about.
971 * Also, it will make PI more or less work without too
972 * much confusion -- but then, stop work should not
973 * rely on PI working anyway.
975 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m);
977 stop->sched_class = &stop_sched_class;
980 cpu_rq(cpu)->stop = stop;
984 * Reset it back to a normal scheduling class so that
985 * it can die in pieces.
987 old_stop->sched_class = &rt_sched_class;
992 * __normal_prio - return the priority that is based on the static prio
994 static inline int __normal_prio(struct task_struct *p)
996 return p->static_prio;
1000 * Calculate the expected normal priority: i.e. priority
1001 * without taking RT-inheritance into account. Might be
1002 * boosted by interactivity modifiers. Changes upon fork,
1003 * setprio syscalls, and whenever the interactivity
1004 * estimator recalculates.
1006 static inline int normal_prio(struct task_struct *p)
1010 if (task_has_rt_policy(p))
1011 prio = MAX_RT_PRIO-1 - p->rt_priority;
1013 prio = __normal_prio(p);
1018 * Calculate the current priority, i.e. the priority
1019 * taken into account by the scheduler. This value might
1020 * be boosted by RT tasks, or might be boosted by
1021 * interactivity modifiers. Will be RT if the task got
1022 * RT-boosted. If not then it returns p->normal_prio.
1024 static int effective_prio(struct task_struct *p)
1026 p->normal_prio = normal_prio(p);
1028 * If we are RT tasks or we were boosted to RT priority,
1029 * keep the priority unchanged. Otherwise, update priority
1030 * to the normal priority:
1032 if (!rt_prio(p->prio))
1033 return p->normal_prio;
1038 * task_curr - is this task currently executing on a CPU?
1039 * @p: the task in question.
1041 inline int task_curr(const struct task_struct *p)
1043 return cpu_curr(task_cpu(p)) == p;
1046 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1047 const struct sched_class *prev_class,
1050 if (prev_class != p->sched_class) {
1051 if (prev_class->switched_from)
1052 prev_class->switched_from(rq, p);
1053 p->sched_class->switched_to(rq, p);
1054 } else if (oldprio != p->prio)
1055 p->sched_class->prio_changed(rq, p, oldprio);
1058 void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
1060 const struct sched_class *class;
1062 if (p->sched_class == rq->curr->sched_class) {
1063 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
1065 for_each_class(class) {
1066 if (class == rq->curr->sched_class)
1068 if (class == p->sched_class) {
1069 resched_task(rq->curr);
1076 * A queue event has occurred, and we're going to schedule. In
1077 * this case, we can save a useless back to back clock update.
1079 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr))
1080 rq->skip_clock_update = 1;
1084 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1086 #ifdef CONFIG_SCHED_DEBUG
1088 * We should never call set_task_cpu() on a blocked task,
1089 * ttwu() will sort out the placement.
1091 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
1092 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
1094 #ifdef CONFIG_LOCKDEP
1096 * The caller should hold either p->pi_lock or rq->lock, when changing
1097 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1099 * sched_move_task() holds both and thus holding either pins the cgroup,
1100 * see set_task_rq().
1102 * Furthermore, all task_rq users should acquire both locks, see
1105 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
1106 lockdep_is_held(&task_rq(p)->lock)));
1110 trace_sched_migrate_task(p, new_cpu);
1112 if (task_cpu(p) != new_cpu) {
1113 p->se.nr_migrations++;
1114 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);
1117 __set_task_cpu(p, new_cpu);
1120 struct migration_arg {
1121 struct task_struct *task;
1125 static int migration_cpu_stop(void *data);
1128 * wait_task_inactive - wait for a thread to unschedule.
1130 * If @match_state is nonzero, it's the @p->state value just checked and
1131 * not expected to change. If it changes, i.e. @p might have woken up,
1132 * then return zero. When we succeed in waiting for @p to be off its CPU,
1133 * we return a positive number (its total switch count). If a second call
1134 * a short while later returns the same number, the caller can be sure that
1135 * @p has remained unscheduled the whole time.
1137 * The caller must ensure that the task *will* unschedule sometime soon,
1138 * else this function might spin for a *long* time. This function can't
1139 * be called with interrupts off, or it may introduce deadlock with
1140 * smp_call_function() if an IPI is sent by the same process we are
1141 * waiting to become inactive.
1143 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1145 unsigned long flags;
1152 * We do the initial early heuristics without holding
1153 * any task-queue locks at all. We'll only try to get
1154 * the runqueue lock when things look like they will
1160 * If the task is actively running on another CPU
1161 * still, just relax and busy-wait without holding
1164 * NOTE! Since we don't hold any locks, it's not
1165 * even sure that "rq" stays as the right runqueue!
1166 * But we don't care, since "task_running()" will
1167 * return false if the runqueue has changed and p
1168 * is actually now running somewhere else!
1170 while (task_running(rq, p)) {
1171 if (match_state && unlikely(p->state != match_state))
1177 * Ok, time to look more closely! We need the rq
1178 * lock now, to be *sure*. If we're wrong, we'll
1179 * just go back and repeat.
1181 rq = task_rq_lock(p, &flags);
1182 trace_sched_wait_task(p);
1183 running = task_running(rq, p);
1186 if (!match_state || p->state == match_state)
1187 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1188 task_rq_unlock(rq, p, &flags);
1191 * If it changed from the expected state, bail out now.
1193 if (unlikely(!ncsw))
1197 * Was it really running after all now that we
1198 * checked with the proper locks actually held?
1200 * Oops. Go back and try again..
1202 if (unlikely(running)) {
1208 * It's not enough that it's not actively running,
1209 * it must be off the runqueue _entirely_, and not
1212 * So if it was still runnable (but just not actively
1213 * running right now), it's preempted, and we should
1214 * yield - it could be a while.
1216 if (unlikely(on_rq)) {
1217 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
1219 set_current_state(TASK_UNINTERRUPTIBLE);
1220 schedule_hrtimeout(&to, HRTIMER_MODE_REL);
1225 * Ahh, all good. It wasn't running, and it wasn't
1226 * runnable, which means that it will never become
1227 * running in the future either. We're all done!
1236 * kick_process - kick a running thread to enter/exit the kernel
1237 * @p: the to-be-kicked thread
1239 * Cause a process which is running on another CPU to enter
1240 * kernel-mode, without any delay. (to get signals handled.)
1242 * NOTE: this function doesn't have to take the runqueue lock,
1243 * because all it wants to ensure is that the remote task enters
1244 * the kernel. If the IPI races and the task has been migrated
1245 * to another CPU then no harm is done and the purpose has been
1248 void kick_process(struct task_struct *p)
1254 if ((cpu != smp_processor_id()) && task_curr(p))
1255 smp_send_reschedule(cpu);
1258 EXPORT_SYMBOL_GPL(kick_process);
1259 #endif /* CONFIG_SMP */
1263 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1265 static int select_fallback_rq(int cpu, struct task_struct *p)
1267 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));
1268 enum { cpuset, possible, fail } state = cpuset;
1271 /* Look for allowed, online CPU in same node. */
1272 for_each_cpu(dest_cpu, nodemask) {
1273 if (!cpu_online(dest_cpu))
1275 if (!cpu_active(dest_cpu))
1277 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
1282 /* Any allowed, online CPU? */
1283 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) {
1284 if (!cpu_online(dest_cpu))
1286 if (!cpu_active(dest_cpu))
1293 /* No more Mr. Nice Guy. */
1294 cpuset_cpus_allowed_fallback(p);
1299 do_set_cpus_allowed(p, cpu_possible_mask);
1310 if (state != cpuset) {
1312 * Don't tell them about moving exiting tasks or
1313 * kernel threads (both mm NULL), since they never
1316 if (p->mm && printk_ratelimit()) {
1317 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1318 task_pid_nr(p), p->comm, cpu);
1326 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1329 int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
1331 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
1334 * In order not to call set_task_cpu() on a blocking task we need
1335 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1338 * Since this is common to all placement strategies, this lives here.
1340 * [ this allows ->select_task() to simply return task_cpu(p) and
1341 * not worry about this generic constraint ]
1343 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
1345 cpu = select_fallback_rq(task_cpu(p), p);
1350 static void update_avg(u64 *avg, u64 sample)
1352 s64 diff = sample - *avg;
1358 ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
1360 #ifdef CONFIG_SCHEDSTATS
1361 struct rq *rq = this_rq();
1364 int this_cpu = smp_processor_id();
1366 if (cpu == this_cpu) {
1367 schedstat_inc(rq, ttwu_local);
1368 schedstat_inc(p, se.statistics.nr_wakeups_local);
1370 struct sched_domain *sd;
1372 schedstat_inc(p, se.statistics.nr_wakeups_remote);
1374 for_each_domain(this_cpu, sd) {
1375 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
1376 schedstat_inc(sd, ttwu_wake_remote);
1383 if (wake_flags & WF_MIGRATED)
1384 schedstat_inc(p, se.statistics.nr_wakeups_migrate);
1386 #endif /* CONFIG_SMP */
1388 schedstat_inc(rq, ttwu_count);
1389 schedstat_inc(p, se.statistics.nr_wakeups);
1391 if (wake_flags & WF_SYNC)
1392 schedstat_inc(p, se.statistics.nr_wakeups_sync);
1394 #endif /* CONFIG_SCHEDSTATS */
1397 static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
1399 activate_task(rq, p, en_flags);
1402 /* if a worker is waking up, notify workqueue */
1403 if (p->flags & PF_WQ_WORKER)
1404 wq_worker_waking_up(p, cpu_of(rq));
1408 * Mark the task runnable and perform wakeup-preemption.
1411 ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
1413 trace_sched_wakeup(p, true);
1414 check_preempt_curr(rq, p, wake_flags);
1416 p->state = TASK_RUNNING;
1418 if (p->sched_class->task_woken)
1419 p->sched_class->task_woken(rq, p);
1421 if (rq->idle_stamp) {
1422 u64 delta = rq->clock - rq->idle_stamp;
1423 u64 max = 2*sysctl_sched_migration_cost;
1428 update_avg(&rq->avg_idle, delta);
1435 ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
1438 if (p->sched_contributes_to_load)
1439 rq->nr_uninterruptible--;
1442 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
1443 ttwu_do_wakeup(rq, p, wake_flags);
1447 * Called in case the task @p isn't fully descheduled from its runqueue,
1448 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1449 * since all we need to do is flip p->state to TASK_RUNNING, since
1450 * the task is still ->on_rq.
1452 static int ttwu_remote(struct task_struct *p, int wake_flags)
1457 rq = __task_rq_lock(p);
1459 ttwu_do_wakeup(rq, p, wake_flags);
1462 __task_rq_unlock(rq);
1468 static void sched_ttwu_pending(void)
1470 struct rq *rq = this_rq();
1471 struct llist_node *llist = llist_del_all(&rq->wake_list);
1472 struct task_struct *p;
1474 raw_spin_lock(&rq->lock);
1477 p = llist_entry(llist, struct task_struct, wake_entry);
1478 llist = llist_next(llist);
1479 ttwu_do_activate(rq, p, 0);
1482 raw_spin_unlock(&rq->lock);
1485 void scheduler_ipi(void)
1487 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
1491 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1492 * traditionally all their work was done from the interrupt return
1493 * path. Now that we actually do some work, we need to make sure
1496 * Some archs already do call them, luckily irq_enter/exit nest
1499 * Arguably we should visit all archs and update all handlers,
1500 * however a fair share of IPIs are still resched only so this would
1501 * somewhat pessimize the simple resched case.
1504 sched_ttwu_pending();
1507 * Check if someone kicked us for doing the nohz idle load balance.
1509 if (unlikely(got_nohz_idle_kick() && !need_resched())) {
1510 this_rq()->idle_balance = 1;
1511 raise_softirq_irqoff(SCHED_SOFTIRQ);
1516 static void ttwu_queue_remote(struct task_struct *p, int cpu)
1518 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list))
1519 smp_send_reschedule(cpu);
1522 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1523 static int ttwu_activate_remote(struct task_struct *p, int wake_flags)
1528 rq = __task_rq_lock(p);
1530 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
1531 ttwu_do_wakeup(rq, p, wake_flags);
1534 __task_rq_unlock(rq);
1539 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1541 bool cpus_share_cache(int this_cpu, int that_cpu)
1543 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
1545 #endif /* CONFIG_SMP */
1547 static void ttwu_queue(struct task_struct *p, int cpu)
1549 struct rq *rq = cpu_rq(cpu);
1551 #if defined(CONFIG_SMP)
1552 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) {
1553 sched_clock_cpu(cpu); /* sync clocks x-cpu */
1554 ttwu_queue_remote(p, cpu);
1559 raw_spin_lock(&rq->lock);
1560 ttwu_do_activate(rq, p, 0);
1561 raw_spin_unlock(&rq->lock);
1565 * try_to_wake_up - wake up a thread
1566 * @p: the thread to be awakened
1567 * @state: the mask of task states that can be woken
1568 * @wake_flags: wake modifier flags (WF_*)
1570 * Put it on the run-queue if it's not already there. The "current"
1571 * thread is always on the run-queue (except when the actual
1572 * re-schedule is in progress), and as such you're allowed to do
1573 * the simpler "current->state = TASK_RUNNING" to mark yourself
1574 * runnable without the overhead of this.
1576 * Returns %true if @p was woken up, %false if it was already running
1577 * or @state didn't match @p's state.
1580 try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
1582 unsigned long flags;
1583 int cpu, success = 0;
1586 raw_spin_lock_irqsave(&p->pi_lock, flags);
1587 if (!(p->state & state))
1590 success = 1; /* we're going to change ->state */
1593 if (p->on_rq && ttwu_remote(p, wake_flags))
1598 * If the owning (remote) cpu is still in the middle of schedule() with
1599 * this task as prev, wait until its done referencing the task.
1602 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1604 * In case the architecture enables interrupts in
1605 * context_switch(), we cannot busy wait, since that
1606 * would lead to deadlocks when an interrupt hits and
1607 * tries to wake up @prev. So bail and do a complete
1610 if (ttwu_activate_remote(p, wake_flags))
1617 * Pairs with the smp_wmb() in finish_lock_switch().
1621 p->sched_contributes_to_load = !!task_contributes_to_load(p);
1622 p->state = TASK_WAKING;
1624 if (p->sched_class->task_waking)
1625 p->sched_class->task_waking(p);
1627 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
1628 if (task_cpu(p) != cpu) {
1629 wake_flags |= WF_MIGRATED;
1630 set_task_cpu(p, cpu);
1632 #endif /* CONFIG_SMP */
1636 ttwu_stat(p, cpu, wake_flags);
1638 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1644 * try_to_wake_up_local - try to wake up a local task with rq lock held
1645 * @p: the thread to be awakened
1647 * Put @p on the run-queue if it's not already there. The caller must
1648 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1651 static void try_to_wake_up_local(struct task_struct *p)
1653 struct rq *rq = task_rq(p);
1655 BUG_ON(rq != this_rq());
1656 BUG_ON(p == current);
1657 lockdep_assert_held(&rq->lock);
1659 if (!raw_spin_trylock(&p->pi_lock)) {
1660 raw_spin_unlock(&rq->lock);
1661 raw_spin_lock(&p->pi_lock);
1662 raw_spin_lock(&rq->lock);
1665 if (!(p->state & TASK_NORMAL))
1669 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
1671 ttwu_do_wakeup(rq, p, 0);
1672 ttwu_stat(p, smp_processor_id(), 0);
1674 raw_spin_unlock(&p->pi_lock);
1678 * wake_up_process - Wake up a specific process
1679 * @p: The process to be woken up.
1681 * Attempt to wake up the nominated process and move it to the set of runnable
1682 * processes. Returns 1 if the process was woken up, 0 if it was already
1685 * It may be assumed that this function implies a write memory barrier before
1686 * changing the task state if and only if any tasks are woken up.
1688 int wake_up_process(struct task_struct *p)
1690 return try_to_wake_up(p, TASK_ALL, 0);
1692 EXPORT_SYMBOL(wake_up_process);
1694 int wake_up_state(struct task_struct *p, unsigned int state)
1696 return try_to_wake_up(p, state, 0);
1700 * Perform scheduler related setup for a newly forked process p.
1701 * p is forked by current.
1703 * __sched_fork() is basic setup used by init_idle() too:
1705 static void __sched_fork(struct task_struct *p)
1710 p->se.exec_start = 0;
1711 p->se.sum_exec_runtime = 0;
1712 p->se.prev_sum_exec_runtime = 0;
1713 p->se.nr_migrations = 0;
1715 INIT_LIST_HEAD(&p->se.group_node);
1717 #ifdef CONFIG_SCHEDSTATS
1718 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
1721 INIT_LIST_HEAD(&p->rt.run_list);
1723 #ifdef CONFIG_PREEMPT_NOTIFIERS
1724 INIT_HLIST_HEAD(&p->preempt_notifiers);
1729 * fork()/clone()-time setup:
1731 void sched_fork(struct task_struct *p)
1733 unsigned long flags;
1734 int cpu = get_cpu();
1738 * We mark the process as running here. This guarantees that
1739 * nobody will actually run it, and a signal or other external
1740 * event cannot wake it up and insert it on the runqueue either.
1742 p->state = TASK_RUNNING;
1745 * Make sure we do not leak PI boosting priority to the child.
1747 p->prio = current->normal_prio;
1750 * Revert to default priority/policy on fork if requested.
1752 if (unlikely(p->sched_reset_on_fork)) {
1753 if (task_has_rt_policy(p)) {
1754 p->policy = SCHED_NORMAL;
1755 p->static_prio = NICE_TO_PRIO(0);
1757 } else if (PRIO_TO_NICE(p->static_prio) < 0)
1758 p->static_prio = NICE_TO_PRIO(0);
1760 p->prio = p->normal_prio = __normal_prio(p);
1764 * We don't need the reset flag anymore after the fork. It has
1765 * fulfilled its duty:
1767 p->sched_reset_on_fork = 0;
1770 if (!rt_prio(p->prio))
1771 p->sched_class = &fair_sched_class;
1773 if (p->sched_class->task_fork)
1774 p->sched_class->task_fork(p);
1777 * The child is not yet in the pid-hash so no cgroup attach races,
1778 * and the cgroup is pinned to this child due to cgroup_fork()
1779 * is ran before sched_fork().
1781 * Silence PROVE_RCU.
1783 raw_spin_lock_irqsave(&p->pi_lock, flags);
1784 set_task_cpu(p, cpu);
1785 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1787 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1788 if (likely(sched_info_on()))
1789 memset(&p->sched_info, 0, sizeof(p->sched_info));
1791 #if defined(CONFIG_SMP)
1794 #ifdef CONFIG_PREEMPT_COUNT
1795 /* Want to start with kernel preemption disabled. */
1796 task_thread_info(p)->preempt_count = 1;
1799 plist_node_init(&p->pushable_tasks, MAX_PRIO);
1806 * wake_up_new_task - wake up a newly created task for the first time.
1808 * This function will do some initial scheduler statistics housekeeping
1809 * that must be done for every newly created context, then puts the task
1810 * on the runqueue and wakes it.
1812 void wake_up_new_task(struct task_struct *p)
1814 unsigned long flags;
1817 raw_spin_lock_irqsave(&p->pi_lock, flags);
1820 * Fork balancing, do it here and not earlier because:
1821 * - cpus_allowed can change in the fork path
1822 * - any previously selected cpu might disappear through hotplug
1824 set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0));
1827 rq = __task_rq_lock(p);
1828 activate_task(rq, p, 0);
1830 trace_sched_wakeup_new(p, true);
1831 check_preempt_curr(rq, p, WF_FORK);
1833 if (p->sched_class->task_woken)
1834 p->sched_class->task_woken(rq, p);
1836 task_rq_unlock(rq, p, &flags);
1839 #ifdef CONFIG_PREEMPT_NOTIFIERS
1842 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1843 * @notifier: notifier struct to register
1845 void preempt_notifier_register(struct preempt_notifier *notifier)
1847 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
1849 EXPORT_SYMBOL_GPL(preempt_notifier_register);
1852 * preempt_notifier_unregister - no longer interested in preemption notifications
1853 * @notifier: notifier struct to unregister
1855 * This is safe to call from within a preemption notifier.
1857 void preempt_notifier_unregister(struct preempt_notifier *notifier)
1859 hlist_del(¬ifier->link);
1861 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
1863 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1865 struct preempt_notifier *notifier;
1866 struct hlist_node *node;
1868 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
1869 notifier->ops->sched_in(notifier, raw_smp_processor_id());
1873 fire_sched_out_preempt_notifiers(struct task_struct *curr,
1874 struct task_struct *next)
1876 struct preempt_notifier *notifier;
1877 struct hlist_node *node;
1879 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
1880 notifier->ops->sched_out(notifier, next);
1883 #else /* !CONFIG_PREEMPT_NOTIFIERS */
1885 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1890 fire_sched_out_preempt_notifiers(struct task_struct *curr,
1891 struct task_struct *next)
1895 #endif /* CONFIG_PREEMPT_NOTIFIERS */
1898 * prepare_task_switch - prepare to switch tasks
1899 * @rq: the runqueue preparing to switch
1900 * @prev: the current task that is being switched out
1901 * @next: the task we are going to switch to.
1903 * This is called with the rq lock held and interrupts off. It must
1904 * be paired with a subsequent finish_task_switch after the context
1907 * prepare_task_switch sets up locking and calls architecture specific
1911 prepare_task_switch(struct rq *rq, struct task_struct *prev,
1912 struct task_struct *next)
1914 sched_info_switch(prev, next);
1915 perf_event_task_sched_out(prev, next);
1916 fire_sched_out_preempt_notifiers(prev, next);
1917 prepare_lock_switch(rq, next);
1918 prepare_arch_switch(next);
1919 trace_sched_switch(prev, next);
1923 * finish_task_switch - clean up after a task-switch
1924 * @rq: runqueue associated with task-switch
1925 * @prev: the thread we just switched away from.
1927 * finish_task_switch must be called after the context switch, paired
1928 * with a prepare_task_switch call before the context switch.
1929 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1930 * and do any other architecture-specific cleanup actions.
1932 * Note that we may have delayed dropping an mm in context_switch(). If
1933 * so, we finish that here outside of the runqueue lock. (Doing it
1934 * with the lock held can cause deadlocks; see schedule() for
1937 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
1938 __releases(rq->lock)
1940 struct mm_struct *mm = rq->prev_mm;
1946 * A task struct has one reference for the use as "current".
1947 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1948 * schedule one last time. The schedule call will never return, and
1949 * the scheduled task must drop that reference.
1950 * The test for TASK_DEAD must occur while the runqueue locks are
1951 * still held, otherwise prev could be scheduled on another cpu, die
1952 * there before we look at prev->state, and then the reference would
1954 * Manfred Spraul <manfred@colorfullife.com>
1956 prev_state = prev->state;
1957 finish_arch_switch(prev);
1958 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1959 local_irq_disable();
1960 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1961 perf_event_task_sched_in(prev, current);
1962 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1964 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1965 finish_lock_switch(rq, prev);
1966 finish_arch_post_lock_switch();
1968 fire_sched_in_preempt_notifiers(current);
1971 if (unlikely(prev_state == TASK_DEAD)) {
1973 * Remove function-return probe instances associated with this
1974 * task and put them back on the free list.
1976 kprobe_flush_task(prev);
1977 put_task_struct(prev);
1983 /* assumes rq->lock is held */
1984 static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
1986 if (prev->sched_class->pre_schedule)
1987 prev->sched_class->pre_schedule(rq, prev);
1990 /* rq->lock is NOT held, but preemption is disabled */
1991 static inline void post_schedule(struct rq *rq)
1993 if (rq->post_schedule) {
1994 unsigned long flags;
1996 raw_spin_lock_irqsave(&rq->lock, flags);
1997 if (rq->curr->sched_class->post_schedule)
1998 rq->curr->sched_class->post_schedule(rq);
1999 raw_spin_unlock_irqrestore(&rq->lock, flags);
2001 rq->post_schedule = 0;
2007 static inline void pre_schedule(struct rq *rq, struct task_struct *p)
2011 static inline void post_schedule(struct rq *rq)
2018 * schedule_tail - first thing a freshly forked thread must call.
2019 * @prev: the thread we just switched away from.
2021 asmlinkage void schedule_tail(struct task_struct *prev)
2022 __releases(rq->lock)
2024 struct rq *rq = this_rq();
2026 finish_task_switch(rq, prev);
2029 * FIXME: do we need to worry about rq being invalidated by the
2034 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2035 /* In this case, finish_task_switch does not reenable preemption */
2038 if (current->set_child_tid)
2039 put_user(task_pid_vnr(current), current->set_child_tid);
2043 * context_switch - switch to the new MM and the new
2044 * thread's register state.
2047 context_switch(struct rq *rq, struct task_struct *prev,
2048 struct task_struct *next)
2050 struct mm_struct *mm, *oldmm;
2052 prepare_task_switch(rq, prev, next);
2055 oldmm = prev->active_mm;
2057 * For paravirt, this is coupled with an exit in switch_to to
2058 * combine the page table reload and the switch backend into
2061 arch_start_context_switch(prev);
2064 next->active_mm = oldmm;
2065 atomic_inc(&oldmm->mm_count);
2066 enter_lazy_tlb(oldmm, next);
2068 switch_mm(oldmm, mm, next);
2071 prev->active_mm = NULL;
2072 rq->prev_mm = oldmm;
2075 * Since the runqueue lock will be released by the next
2076 * task (which is an invalid locking op but in the case
2077 * of the scheduler it's an obvious special-case), so we
2078 * do an early lockdep release here:
2080 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2081 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2084 /* Here we just switch the register state and the stack. */
2085 rcu_switch_from(prev);
2086 switch_to(prev, next, prev);
2090 * this_rq must be evaluated again because prev may have moved
2091 * CPUs since it called schedule(), thus the 'rq' on its stack
2092 * frame will be invalid.
2094 finish_task_switch(this_rq(), prev);
2098 * nr_running, nr_uninterruptible and nr_context_switches:
2100 * externally visible scheduler statistics: current number of runnable
2101 * threads, current number of uninterruptible-sleeping threads, total
2102 * number of context switches performed since bootup.
2104 unsigned long nr_running(void)
2106 unsigned long i, sum = 0;
2108 for_each_online_cpu(i)
2109 sum += cpu_rq(i)->nr_running;
2114 unsigned long nr_uninterruptible(void)
2116 unsigned long i, sum = 0;
2118 for_each_possible_cpu(i)
2119 sum += cpu_rq(i)->nr_uninterruptible;
2122 * Since we read the counters lockless, it might be slightly
2123 * inaccurate. Do not allow it to go below zero though:
2125 if (unlikely((long)sum < 0))
2131 unsigned long long nr_context_switches(void)
2134 unsigned long long sum = 0;
2136 for_each_possible_cpu(i)
2137 sum += cpu_rq(i)->nr_switches;
2142 unsigned long nr_iowait(void)
2144 unsigned long i, sum = 0;
2146 for_each_possible_cpu(i)
2147 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2152 unsigned long nr_iowait_cpu(int cpu)
2154 struct rq *this = cpu_rq(cpu);
2155 return atomic_read(&this->nr_iowait);
2158 unsigned long this_cpu_load(void)
2160 struct rq *this = this_rq();
2161 return this->cpu_load[0];
2165 /* Variables and functions for calc_load */
2166 static atomic_long_t calc_load_tasks;
2167 static unsigned long calc_load_update;
2168 unsigned long avenrun[3];
2169 EXPORT_SYMBOL(avenrun);
2171 static long calc_load_fold_active(struct rq *this_rq)
2173 long nr_active, delta = 0;
2175 nr_active = this_rq->nr_running;
2176 nr_active += (long) this_rq->nr_uninterruptible;
2178 if (nr_active != this_rq->calc_load_active) {
2179 delta = nr_active - this_rq->calc_load_active;
2180 this_rq->calc_load_active = nr_active;
2186 static unsigned long
2187 calc_load(unsigned long load, unsigned long exp, unsigned long active)
2190 load += active * (FIXED_1 - exp);
2191 load += 1UL << (FSHIFT - 1);
2192 return load >> FSHIFT;
2197 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
2199 * When making the ILB scale, we should try to pull this in as well.
2201 static atomic_long_t calc_load_tasks_idle;
2203 void calc_load_account_idle(struct rq *this_rq)
2207 delta = calc_load_fold_active(this_rq);
2209 atomic_long_add(delta, &calc_load_tasks_idle);
2212 static long calc_load_fold_idle(void)
2217 * Its got a race, we don't care...
2219 if (atomic_long_read(&calc_load_tasks_idle))
2220 delta = atomic_long_xchg(&calc_load_tasks_idle, 0);
2226 * fixed_power_int - compute: x^n, in O(log n) time
2228 * @x: base of the power
2229 * @frac_bits: fractional bits of @x
2230 * @n: power to raise @x to.
2232 * By exploiting the relation between the definition of the natural power
2233 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
2234 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
2235 * (where: n_i \elem {0, 1}, the binary vector representing n),
2236 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
2237 * of course trivially computable in O(log_2 n), the length of our binary
2240 static unsigned long
2241 fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
2243 unsigned long result = 1UL << frac_bits;
2248 result += 1UL << (frac_bits - 1);
2249 result >>= frac_bits;
2255 x += 1UL << (frac_bits - 1);
2263 * a1 = a0 * e + a * (1 - e)
2265 * a2 = a1 * e + a * (1 - e)
2266 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
2267 * = a0 * e^2 + a * (1 - e) * (1 + e)
2269 * a3 = a2 * e + a * (1 - e)
2270 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
2271 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
2275 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
2276 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
2277 * = a0 * e^n + a * (1 - e^n)
2279 * [1] application of the geometric series:
2282 * S_n := \Sum x^i = -------------
2285 static unsigned long
2286 calc_load_n(unsigned long load, unsigned long exp,
2287 unsigned long active, unsigned int n)
2290 return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
2294 * NO_HZ can leave us missing all per-cpu ticks calling
2295 * calc_load_account_active(), but since an idle CPU folds its delta into
2296 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
2297 * in the pending idle delta if our idle period crossed a load cycle boundary.
2299 * Once we've updated the global active value, we need to apply the exponential
2300 * weights adjusted to the number of cycles missed.
2302 static void calc_global_nohz(void)
2304 long delta, active, n;
2307 * If we crossed a calc_load_update boundary, make sure to fold
2308 * any pending idle changes, the respective CPUs might have
2309 * missed the tick driven calc_load_account_active() update
2312 delta = calc_load_fold_idle();
2314 atomic_long_add(delta, &calc_load_tasks);
2317 * It could be the one fold was all it took, we done!
2319 if (time_before(jiffies, calc_load_update + 10))
2323 * Catch-up, fold however many we are behind still
2325 delta = jiffies - calc_load_update - 10;
2326 n = 1 + (delta / LOAD_FREQ);
2328 active = atomic_long_read(&calc_load_tasks);
2329 active = active > 0 ? active * FIXED_1 : 0;
2331 avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
2332 avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
2333 avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
2335 calc_load_update += n * LOAD_FREQ;
2338 void calc_load_account_idle(struct rq *this_rq)
2342 static inline long calc_load_fold_idle(void)
2347 static void calc_global_nohz(void)
2353 * get_avenrun - get the load average array
2354 * @loads: pointer to dest load array
2355 * @offset: offset to add
2356 * @shift: shift count to shift the result left
2358 * These values are estimates at best, so no need for locking.
2360 void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
2362 loads[0] = (avenrun[0] + offset) << shift;
2363 loads[1] = (avenrun[1] + offset) << shift;
2364 loads[2] = (avenrun[2] + offset) << shift;
2368 * calc_load - update the avenrun load estimates 10 ticks after the
2369 * CPUs have updated calc_load_tasks.
2371 void calc_global_load(unsigned long ticks)
2375 if (time_before(jiffies, calc_load_update + 10))
2378 active = atomic_long_read(&calc_load_tasks);
2379 active = active > 0 ? active * FIXED_1 : 0;
2381 avenrun[0] = calc_load(avenrun[0], EXP_1, active);
2382 avenrun[1] = calc_load(avenrun[1], EXP_5, active);
2383 avenrun[2] = calc_load(avenrun[2], EXP_15, active);
2385 calc_load_update += LOAD_FREQ;
2388 * Account one period with whatever state we found before
2389 * folding in the nohz state and ageing the entire idle period.
2391 * This avoids loosing a sample when we go idle between
2392 * calc_load_account_active() (10 ticks ago) and now and thus
2399 * Called from update_cpu_load() to periodically update this CPU's
2402 static void calc_load_account_active(struct rq *this_rq)
2406 if (time_before(jiffies, this_rq->calc_load_update))
2409 delta = calc_load_fold_active(this_rq);
2410 delta += calc_load_fold_idle();
2412 atomic_long_add(delta, &calc_load_tasks);
2414 this_rq->calc_load_update += LOAD_FREQ;
2418 * The exact cpuload at various idx values, calculated at every tick would be
2419 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
2421 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
2422 * on nth tick when cpu may be busy, then we have:
2423 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2424 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
2426 * decay_load_missed() below does efficient calculation of
2427 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2428 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
2430 * The calculation is approximated on a 128 point scale.
2431 * degrade_zero_ticks is the number of ticks after which load at any
2432 * particular idx is approximated to be zero.
2433 * degrade_factor is a precomputed table, a row for each load idx.
2434 * Each column corresponds to degradation factor for a power of two ticks,
2435 * based on 128 point scale.
2437 * row 2, col 3 (=12) says that the degradation at load idx 2 after
2438 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
2440 * With this power of 2 load factors, we can degrade the load n times
2441 * by looking at 1 bits in n and doing as many mult/shift instead of
2442 * n mult/shifts needed by the exact degradation.
2444 #define DEGRADE_SHIFT 7
2445 static const unsigned char
2446 degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128};
2447 static const unsigned char
2448 degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = {
2449 {0, 0, 0, 0, 0, 0, 0, 0},
2450 {64, 32, 8, 0, 0, 0, 0, 0},
2451 {96, 72, 40, 12, 1, 0, 0},
2452 {112, 98, 75, 43, 15, 1, 0},
2453 {120, 112, 98, 76, 45, 16, 2} };
2456 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
2457 * would be when CPU is idle and so we just decay the old load without
2458 * adding any new load.
2460 static unsigned long
2461 decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
2465 if (!missed_updates)
2468 if (missed_updates >= degrade_zero_ticks[idx])
2472 return load >> missed_updates;
2474 while (missed_updates) {
2475 if (missed_updates % 2)
2476 load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT;
2478 missed_updates >>= 1;
2485 * Update rq->cpu_load[] statistics. This function is usually called every
2486 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
2487 * every tick. We fix it up based on jiffies.
2489 static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
2490 unsigned long pending_updates)
2494 this_rq->nr_load_updates++;
2496 /* Update our load: */
2497 this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
2498 for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2499 unsigned long old_load, new_load;
2501 /* scale is effectively 1 << i now, and >> i divides by scale */
2503 old_load = this_rq->cpu_load[i];
2504 old_load = decay_load_missed(old_load, pending_updates - 1, i);
2505 new_load = this_load;
2507 * Round up the averaging division if load is increasing. This
2508 * prevents us from getting stuck on 9 if the load is 10, for
2511 if (new_load > old_load)
2512 new_load += scale - 1;
2514 this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
2517 sched_avg_update(this_rq);
2521 * Called from nohz_idle_balance() to update the load ratings before doing the
2524 void update_idle_cpu_load(struct rq *this_rq)
2526 unsigned long curr_jiffies = jiffies;
2527 unsigned long load = this_rq->load.weight;
2528 unsigned long pending_updates;
2531 * Bloody broken means of dealing with nohz, but better than nothing..
2532 * jiffies is updated by one cpu, another cpu can drift wrt the jiffy
2533 * update and see 0 difference the one time and 2 the next, even though
2534 * we ticked at roughtly the same rate.
2536 * Hence we only use this from nohz_idle_balance() and skip this
2537 * nonsense when called from the scheduler_tick() since that's
2538 * guaranteed a stable rate.
2540 if (load || curr_jiffies == this_rq->last_load_update_tick)
2543 pending_updates = curr_jiffies - this_rq->last_load_update_tick;
2544 this_rq->last_load_update_tick = curr_jiffies;
2546 __update_cpu_load(this_rq, load, pending_updates);
2550 * Called from scheduler_tick()
2552 static void update_cpu_load_active(struct rq *this_rq)
2555 * See the mess in update_idle_cpu_load().
2557 this_rq->last_load_update_tick = jiffies;
2558 __update_cpu_load(this_rq, this_rq->load.weight, 1);
2560 calc_load_account_active(this_rq);
2566 * sched_exec - execve() is a valuable balancing opportunity, because at
2567 * this point the task has the smallest effective memory and cache footprint.
2569 void sched_exec(void)
2571 struct task_struct *p = current;
2572 unsigned long flags;
2575 raw_spin_lock_irqsave(&p->pi_lock, flags);
2576 dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0);
2577 if (dest_cpu == smp_processor_id())
2580 if (likely(cpu_active(dest_cpu))) {
2581 struct migration_arg arg = { p, dest_cpu };
2583 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2584 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
2588 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2593 DEFINE_PER_CPU(struct kernel_stat, kstat);
2594 DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
2596 EXPORT_PER_CPU_SYMBOL(kstat);
2597 EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
2600 * Return any ns on the sched_clock that have not yet been accounted in
2601 * @p in case that task is currently running.
2603 * Called with task_rq_lock() held on @rq.
2605 static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
2609 if (task_current(rq, p)) {
2610 update_rq_clock(rq);
2611 ns = rq->clock_task - p->se.exec_start;
2619 unsigned long long task_delta_exec(struct task_struct *p)
2621 unsigned long flags;
2625 rq = task_rq_lock(p, &flags);
2626 ns = do_task_delta_exec(p, rq);
2627 task_rq_unlock(rq, p, &flags);
2633 * Return accounted runtime for the task.
2634 * In case the task is currently running, return the runtime plus current's
2635 * pending runtime that have not been accounted yet.
2637 unsigned long long task_sched_runtime(struct task_struct *p)
2639 unsigned long flags;
2643 rq = task_rq_lock(p, &flags);
2644 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
2645 task_rq_unlock(rq, p, &flags);
2650 #ifdef CONFIG_CGROUP_CPUACCT
2651 struct cgroup_subsys cpuacct_subsys;
2652 struct cpuacct root_cpuacct;
2655 static inline void task_group_account_field(struct task_struct *p, int index,
2658 #ifdef CONFIG_CGROUP_CPUACCT
2659 struct kernel_cpustat *kcpustat;
2663 * Since all updates are sure to touch the root cgroup, we
2664 * get ourselves ahead and touch it first. If the root cgroup
2665 * is the only cgroup, then nothing else should be necessary.
2668 __get_cpu_var(kernel_cpustat).cpustat[index] += tmp;
2670 #ifdef CONFIG_CGROUP_CPUACCT
2671 if (unlikely(!cpuacct_subsys.active))
2676 while (ca && (ca != &root_cpuacct)) {
2677 kcpustat = this_cpu_ptr(ca->cpustat);
2678 kcpustat->cpustat[index] += tmp;
2687 * Account user cpu time to a process.
2688 * @p: the process that the cpu time gets accounted to
2689 * @cputime: the cpu time spent in user space since the last update
2690 * @cputime_scaled: cputime scaled by cpu frequency
2692 void account_user_time(struct task_struct *p, cputime_t cputime,
2693 cputime_t cputime_scaled)
2697 /* Add user time to process. */
2698 p->utime += cputime;
2699 p->utimescaled += cputime_scaled;
2700 account_group_user_time(p, cputime);
2702 index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
2704 /* Add user time to cpustat. */
2705 task_group_account_field(p, index, (__force u64) cputime);
2707 /* Account for user time used */
2708 acct_update_integrals(p);
2712 * Account guest cpu time to a process.
2713 * @p: the process that the cpu time gets accounted to
2714 * @cputime: the cpu time spent in virtual machine since the last update
2715 * @cputime_scaled: cputime scaled by cpu frequency
2717 static void account_guest_time(struct task_struct *p, cputime_t cputime,
2718 cputime_t cputime_scaled)
2720 u64 *cpustat = kcpustat_this_cpu->cpustat;
2722 /* Add guest time to process. */
2723 p->utime += cputime;
2724 p->utimescaled += cputime_scaled;
2725 account_group_user_time(p, cputime);
2726 p->gtime += cputime;
2728 /* Add guest time to cpustat. */
2729 if (TASK_NICE(p) > 0) {
2730 cpustat[CPUTIME_NICE] += (__force u64) cputime;
2731 cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;
2733 cpustat[CPUTIME_USER] += (__force u64) cputime;
2734 cpustat[CPUTIME_GUEST] += (__force u64) cputime;
2739 * Account system cpu time to a process and desired cpustat field
2740 * @p: the process that the cpu time gets accounted to
2741 * @cputime: the cpu time spent in kernel space since the last update
2742 * @cputime_scaled: cputime scaled by cpu frequency
2743 * @target_cputime64: pointer to cpustat field that has to be updated
2746 void __account_system_time(struct task_struct *p, cputime_t cputime,
2747 cputime_t cputime_scaled, int index)
2749 /* Add system time to process. */
2750 p->stime += cputime;
2751 p->stimescaled += cputime_scaled;
2752 account_group_system_time(p, cputime);
2754 /* Add system time to cpustat. */
2755 task_group_account_field(p, index, (__force u64) cputime);
2757 /* Account for system time used */
2758 acct_update_integrals(p);
2762 * Account system cpu time to a process.
2763 * @p: the process that the cpu time gets accounted to
2764 * @hardirq_offset: the offset to subtract from hardirq_count()
2765 * @cputime: the cpu time spent in kernel space since the last update
2766 * @cputime_scaled: cputime scaled by cpu frequency
2768 void account_system_time(struct task_struct *p, int hardirq_offset,
2769 cputime_t cputime, cputime_t cputime_scaled)
2773 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
2774 account_guest_time(p, cputime, cputime_scaled);
2778 if (hardirq_count() - hardirq_offset)
2779 index = CPUTIME_IRQ;
2780 else if (in_serving_softirq())
2781 index = CPUTIME_SOFTIRQ;
2783 index = CPUTIME_SYSTEM;
2785 __account_system_time(p, cputime, cputime_scaled, index);
2789 * Account for involuntary wait time.
2790 * @cputime: the cpu time spent in involuntary wait
2792 void account_steal_time(cputime_t cputime)
2794 u64 *cpustat = kcpustat_this_cpu->cpustat;
2796 cpustat[CPUTIME_STEAL] += (__force u64) cputime;
2800 * Account for idle time.
2801 * @cputime: the cpu time spent in idle wait
2803 void account_idle_time(cputime_t cputime)
2805 u64 *cpustat = kcpustat_this_cpu->cpustat;
2806 struct rq *rq = this_rq();
2808 if (atomic_read(&rq->nr_iowait) > 0)
2809 cpustat[CPUTIME_IOWAIT] += (__force u64) cputime;
2811 cpustat[CPUTIME_IDLE] += (__force u64) cputime;
2814 static __always_inline bool steal_account_process_tick(void)
2816 #ifdef CONFIG_PARAVIRT
2817 if (static_key_false(¶virt_steal_enabled)) {
2820 steal = paravirt_steal_clock(smp_processor_id());
2821 steal -= this_rq()->prev_steal_time;
2823 st = steal_ticks(steal);
2824 this_rq()->prev_steal_time += st * TICK_NSEC;
2826 account_steal_time(st);
2833 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
2835 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
2837 * Account a tick to a process and cpustat
2838 * @p: the process that the cpu time gets accounted to
2839 * @user_tick: is the tick from userspace
2840 * @rq: the pointer to rq
2842 * Tick demultiplexing follows the order
2843 * - pending hardirq update
2844 * - pending softirq update
2848 * - check for guest_time
2849 * - else account as system_time
2851 * Check for hardirq is done both for system and user time as there is
2852 * no timer going off while we are on hardirq and hence we may never get an
2853 * opportunity to update it solely in system time.
2854 * p->stime and friends are only updated on system time and not on irq
2855 * softirq as those do not count in task exec_runtime any more.
2857 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
2860 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
2861 u64 *cpustat = kcpustat_this_cpu->cpustat;
2863 if (steal_account_process_tick())
2866 if (irqtime_account_hi_update()) {
2867 cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
2868 } else if (irqtime_account_si_update()) {
2869 cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
2870 } else if (this_cpu_ksoftirqd() == p) {
2872 * ksoftirqd time do not get accounted in cpu_softirq_time.
2873 * So, we have to handle it separately here.
2874 * Also, p->stime needs to be updated for ksoftirqd.
2876 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
2878 } else if (user_tick) {
2879 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
2880 } else if (p == rq->idle) {
2881 account_idle_time(cputime_one_jiffy);
2882 } else if (p->flags & PF_VCPU) { /* System time or guest time */
2883 account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
2885 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
2890 static void irqtime_account_idle_ticks(int ticks)
2893 struct rq *rq = this_rq();
2895 for (i = 0; i < ticks; i++)
2896 irqtime_account_process_tick(current, 0, rq);
2898 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
2899 static void irqtime_account_idle_ticks(int ticks) {}
2900 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
2902 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
2905 * Account a single tick of cpu time.
2906 * @p: the process that the cpu time gets accounted to
2907 * @user_tick: indicates if the tick is a user or a system tick
2909 void account_process_tick(struct task_struct *p, int user_tick)
2911 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
2912 struct rq *rq = this_rq();
2914 if (sched_clock_irqtime) {
2915 irqtime_account_process_tick(p, user_tick, rq);
2919 if (steal_account_process_tick())
2923 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
2924 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
2925 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
2928 account_idle_time(cputime_one_jiffy);
2932 * Account multiple ticks of steal time.
2933 * @p: the process from which the cpu time has been stolen
2934 * @ticks: number of stolen ticks
2936 void account_steal_ticks(unsigned long ticks)
2938 account_steal_time(jiffies_to_cputime(ticks));
2942 * Account multiple ticks of idle time.
2943 * @ticks: number of stolen ticks
2945 void account_idle_ticks(unsigned long ticks)
2948 if (sched_clock_irqtime) {
2949 irqtime_account_idle_ticks(ticks);
2953 account_idle_time(jiffies_to_cputime(ticks));
2959 * Use precise platform statistics if available:
2961 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
2962 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2968 void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2970 struct task_cputime cputime;
2972 thread_group_cputime(p, &cputime);
2974 *ut = cputime.utime;
2975 *st = cputime.stime;
2979 #ifndef nsecs_to_cputime
2980 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
2983 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
2985 cputime_t rtime, utime = p->utime, total = utime + p->stime;
2988 * Use CFS's precise accounting:
2990 rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
2993 u64 temp = (__force u64) rtime;
2995 temp *= (__force u64) utime;
2996 do_div(temp, (__force u32) total);
2997 utime = (__force cputime_t) temp;
3002 * Compare with previous values, to keep monotonicity:
3004 p->prev_utime = max(p->prev_utime, utime);
3005 p->prev_stime = max(p->prev_stime, rtime - p->prev_utime);
3007 *ut = p->prev_utime;
3008 *st = p->prev_stime;
3012 * Must be called with siglock held.
3014 void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3016 struct signal_struct *sig = p->signal;
3017 struct task_cputime cputime;
3018 cputime_t rtime, utime, total;
3020 thread_group_cputime(p, &cputime);
3022 total = cputime.utime + cputime.stime;
3023 rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
3026 u64 temp = (__force u64) rtime;
3028 temp *= (__force u64) cputime.utime;
3029 do_div(temp, (__force u32) total);
3030 utime = (__force cputime_t) temp;
3034 sig->prev_utime = max(sig->prev_utime, utime);
3035 sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime);
3037 *ut = sig->prev_utime;
3038 *st = sig->prev_stime;
3043 * This function gets called by the timer code, with HZ frequency.
3044 * We call it with interrupts disabled.
3046 void scheduler_tick(void)
3048 int cpu = smp_processor_id();
3049 struct rq *rq = cpu_rq(cpu);
3050 struct task_struct *curr = rq->curr;
3054 raw_spin_lock(&rq->lock);
3055 update_rq_clock(rq);
3056 update_cpu_load_active(rq);
3057 curr->sched_class->task_tick(rq, curr, 0);
3058 raw_spin_unlock(&rq->lock);
3060 perf_event_task_tick();
3063 rq->idle_balance = idle_cpu(cpu);
3064 trigger_load_balance(rq, cpu);
3068 notrace unsigned long get_parent_ip(unsigned long addr)
3070 if (in_lock_functions(addr)) {
3071 addr = CALLER_ADDR2;
3072 if (in_lock_functions(addr))
3073 addr = CALLER_ADDR3;
3078 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3079 defined(CONFIG_PREEMPT_TRACER))
3081 void __kprobes add_preempt_count(int val)
3083 #ifdef CONFIG_DEBUG_PREEMPT
3087 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3090 preempt_count() += val;
3091 #ifdef CONFIG_DEBUG_PREEMPT
3093 * Spinlock count overflowing soon?
3095 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
3098 if (preempt_count() == val)
3099 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3101 EXPORT_SYMBOL(add_preempt_count);
3103 void __kprobes sub_preempt_count(int val)
3105 #ifdef CONFIG_DEBUG_PREEMPT
3109 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3112 * Is the spinlock portion underflowing?
3114 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
3115 !(preempt_count() & PREEMPT_MASK)))
3119 if (preempt_count() == val)
3120 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3121 preempt_count() -= val;
3123 EXPORT_SYMBOL(sub_preempt_count);
3128 * Print scheduling while atomic bug:
3130 static noinline void __schedule_bug(struct task_struct *prev)
3132 if (oops_in_progress)
3135 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
3136 prev->comm, prev->pid, preempt_count());
3138 debug_show_held_locks(prev);
3140 if (irqs_disabled())
3141 print_irqtrace_events(prev);
3143 add_taint(TAINT_WARN);
3147 * Various schedule()-time debugging checks and statistics:
3149 static inline void schedule_debug(struct task_struct *prev)
3152 * Test if we are atomic. Since do_exit() needs to call into
3153 * schedule() atomically, we ignore that path for now.
3154 * Otherwise, whine if we are scheduling when we should not be.
3156 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
3157 __schedule_bug(prev);
3160 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
3162 schedstat_inc(this_rq(), sched_count);
3165 static void put_prev_task(struct rq *rq, struct task_struct *prev)
3167 if (prev->on_rq || rq->skip_clock_update < 0)
3168 update_rq_clock(rq);
3169 prev->sched_class->put_prev_task(rq, prev);
3173 * Pick up the highest-prio task:
3175 static inline struct task_struct *
3176 pick_next_task(struct rq *rq)
3178 const struct sched_class *class;
3179 struct task_struct *p;
3182 * Optimization: we know that if all tasks are in
3183 * the fair class we can call that function directly:
3185 if (likely(rq->nr_running == rq->cfs.h_nr_running)) {
3186 p = fair_sched_class.pick_next_task(rq);
3191 for_each_class(class) {
3192 p = class->pick_next_task(rq);
3197 BUG(); /* the idle class will always have a runnable task */
3201 * __schedule() is the main scheduler function.
3203 static void __sched __schedule(void)
3205 struct task_struct *prev, *next;
3206 unsigned long *switch_count;
3212 cpu = smp_processor_id();
3214 rcu_note_context_switch(cpu);
3217 schedule_debug(prev);
3219 if (sched_feat(HRTICK))
3222 raw_spin_lock_irq(&rq->lock);
3224 switch_count = &prev->nivcsw;
3225 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
3226 if (unlikely(signal_pending_state(prev->state, prev))) {
3227 prev->state = TASK_RUNNING;
3229 deactivate_task(rq, prev, DEQUEUE_SLEEP);
3233 * If a worker went to sleep, notify and ask workqueue
3234 * whether it wants to wake up a task to maintain
3237 if (prev->flags & PF_WQ_WORKER) {
3238 struct task_struct *to_wakeup;
3240 to_wakeup = wq_worker_sleeping(prev, cpu);
3242 try_to_wake_up_local(to_wakeup);
3245 switch_count = &prev->nvcsw;
3248 pre_schedule(rq, prev);
3250 if (unlikely(!rq->nr_running))
3251 idle_balance(cpu, rq);
3253 put_prev_task(rq, prev);
3254 next = pick_next_task(rq);
3255 clear_tsk_need_resched(prev);
3256 rq->skip_clock_update = 0;
3258 if (likely(prev != next)) {
3263 context_switch(rq, prev, next); /* unlocks the rq */
3265 * The context switch have flipped the stack from under us
3266 * and restored the local variables which were saved when
3267 * this task called schedule() in the past. prev == current
3268 * is still correct, but it can be moved to another cpu/rq.
3270 cpu = smp_processor_id();
3273 raw_spin_unlock_irq(&rq->lock);
3277 sched_preempt_enable_no_resched();
3282 static inline void sched_submit_work(struct task_struct *tsk)
3284 if (!tsk->state || tsk_is_pi_blocked(tsk))
3287 * If we are going to sleep and we have plugged IO queued,
3288 * make sure to submit it to avoid deadlocks.
3290 if (blk_needs_flush_plug(tsk))
3291 blk_schedule_flush_plug(tsk);
3294 asmlinkage void __sched schedule(void)
3296 struct task_struct *tsk = current;
3298 sched_submit_work(tsk);
3301 EXPORT_SYMBOL(schedule);
3304 * schedule_preempt_disabled - called with preemption disabled
3306 * Returns with preemption disabled. Note: preempt_count must be 1
3308 void __sched schedule_preempt_disabled(void)
3310 sched_preempt_enable_no_resched();
3315 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3317 static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
3319 if (lock->owner != owner)
3323 * Ensure we emit the owner->on_cpu, dereference _after_ checking
3324 * lock->owner still matches owner, if that fails, owner might
3325 * point to free()d memory, if it still matches, the rcu_read_lock()
3326 * ensures the memory stays valid.
3330 return owner->on_cpu;
3334 * Look out! "owner" is an entirely speculative pointer
3335 * access and not reliable.
3337 int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
3339 if (!sched_feat(OWNER_SPIN))
3343 while (owner_running(lock, owner)) {
3347 arch_mutex_cpu_relax();
3352 * We break out the loop above on need_resched() and when the
3353 * owner changed, which is a sign for heavy contention. Return
3354 * success only when lock->owner is NULL.
3356 return lock->owner == NULL;
3360 #ifdef CONFIG_PREEMPT
3362 * this is the entry point to schedule() from in-kernel preemption
3363 * off of preempt_enable. Kernel preemptions off return from interrupt
3364 * occur there and call schedule directly.
3366 asmlinkage void __sched notrace preempt_schedule(void)
3368 struct thread_info *ti = current_thread_info();
3371 * If there is a non-zero preempt_count or interrupts are disabled,
3372 * we do not want to preempt the current task. Just return..
3374 if (likely(ti->preempt_count || irqs_disabled()))
3378 add_preempt_count_notrace(PREEMPT_ACTIVE);
3380 sub_preempt_count_notrace(PREEMPT_ACTIVE);
3383 * Check again in case we missed a preemption opportunity
3384 * between schedule and now.
3387 } while (need_resched());
3389 EXPORT_SYMBOL(preempt_schedule);
3392 * this is the entry point to schedule() from kernel preemption
3393 * off of irq context.
3394 * Note, that this is called and return with irqs disabled. This will
3395 * protect us against recursive calling from irq.
3397 asmlinkage void __sched preempt_schedule_irq(void)
3399 struct thread_info *ti = current_thread_info();
3401 /* Catch callers which need to be fixed */
3402 BUG_ON(ti->preempt_count || !irqs_disabled());
3405 add_preempt_count(PREEMPT_ACTIVE);
3408 local_irq_disable();
3409 sub_preempt_count(PREEMPT_ACTIVE);
3412 * Check again in case we missed a preemption opportunity
3413 * between schedule and now.
3416 } while (need_resched());
3419 #endif /* CONFIG_PREEMPT */
3421 int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
3424 return try_to_wake_up(curr->private, mode, wake_flags);
3426 EXPORT_SYMBOL(default_wake_function);
3429 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3430 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3431 * number) then we wake all the non-exclusive tasks and one exclusive task.
3433 * There are circumstances in which we can try to wake a task which has already
3434 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3435 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3437 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
3438 int nr_exclusive, int wake_flags, void *key)
3440 wait_queue_t *curr, *next;
3442 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
3443 unsigned flags = curr->flags;
3445 if (curr->func(curr, mode, wake_flags, key) &&
3446 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
3452 * __wake_up - wake up threads blocked on a waitqueue.
3454 * @mode: which threads
3455 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3456 * @key: is directly passed to the wakeup function
3458 * It may be assumed that this function implies a write memory barrier before
3459 * changing the task state if and only if any tasks are woken up.
3461 void __wake_up(wait_queue_head_t *q, unsigned int mode,
3462 int nr_exclusive, void *key)
3464 unsigned long flags;
3466 spin_lock_irqsave(&q->lock, flags);
3467 __wake_up_common(q, mode, nr_exclusive, 0, key);
3468 spin_unlock_irqrestore(&q->lock, flags);
3470 EXPORT_SYMBOL(__wake_up);
3473 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3475 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr)
3477 __wake_up_common(q, mode, nr, 0, NULL);
3479 EXPORT_SYMBOL_GPL(__wake_up_locked);
3481 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
3483 __wake_up_common(q, mode, 1, 0, key);
3485 EXPORT_SYMBOL_GPL(__wake_up_locked_key);
3488 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
3490 * @mode: which threads
3491 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3492 * @key: opaque value to be passed to wakeup targets
3494 * The sync wakeup differs that the waker knows that it will schedule
3495 * away soon, so while the target thread will be woken up, it will not
3496 * be migrated to another CPU - ie. the two threads are 'synchronized'
3497 * with each other. This can prevent needless bouncing between CPUs.
3499 * On UP it can prevent extra preemption.
3501 * It may be assumed that this function implies a write memory barrier before
3502 * changing the task state if and only if any tasks are woken up.
3504 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
3505 int nr_exclusive, void *key)
3507 unsigned long flags;
3508 int wake_flags = WF_SYNC;
3513 if (unlikely(!nr_exclusive))
3516 spin_lock_irqsave(&q->lock, flags);
3517 __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
3518 spin_unlock_irqrestore(&q->lock, flags);
3520 EXPORT_SYMBOL_GPL(__wake_up_sync_key);
3523 * __wake_up_sync - see __wake_up_sync_key()
3525 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
3527 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
3529 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
3532 * complete: - signals a single thread waiting on this completion
3533 * @x: holds the state of this particular completion
3535 * This will wake up a single thread waiting on this completion. Threads will be
3536 * awakened in the same order in which they were queued.
3538 * See also complete_all(), wait_for_completion() and related routines.
3540 * It may be assumed that this function implies a write memory barrier before
3541 * changing the task state if and only if any tasks are woken up.
3543 void complete(struct completion *x)
3545 unsigned long flags;
3547 spin_lock_irqsave(&x->wait.lock, flags);
3549 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
3550 spin_unlock_irqrestore(&x->wait.lock, flags);
3552 EXPORT_SYMBOL(complete);
3555 * complete_all: - signals all threads waiting on this completion
3556 * @x: holds the state of this particular completion
3558 * This will wake up all threads waiting on this particular completion event.
3560 * It may be assumed that this function implies a write memory barrier before
3561 * changing the task state if and only if any tasks are woken up.
3563 void complete_all(struct completion *x)
3565 unsigned long flags;
3567 spin_lock_irqsave(&x->wait.lock, flags);
3568 x->done += UINT_MAX/2;
3569 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
3570 spin_unlock_irqrestore(&x->wait.lock, flags);
3572 EXPORT_SYMBOL(complete_all);
3574 static inline long __sched
3575 do_wait_for_common(struct completion *x, long timeout, int state)
3578 DECLARE_WAITQUEUE(wait, current);
3580 __add_wait_queue_tail_exclusive(&x->wait, &wait);
3582 if (signal_pending_state(state, current)) {
3583 timeout = -ERESTARTSYS;
3586 __set_current_state(state);
3587 spin_unlock_irq(&x->wait.lock);
3588 timeout = schedule_timeout(timeout);
3589 spin_lock_irq(&x->wait.lock);
3590 } while (!x->done && timeout);
3591 __remove_wait_queue(&x->wait, &wait);
3596 return timeout ?: 1;
3600 wait_for_common(struct completion *x, long timeout, int state)
3604 spin_lock_irq(&x->wait.lock);
3605 timeout = do_wait_for_common(x, timeout, state);
3606 spin_unlock_irq(&x->wait.lock);
3611 * wait_for_completion: - waits for completion of a task
3612 * @x: holds the state of this particular completion
3614 * This waits to be signaled for completion of a specific task. It is NOT
3615 * interruptible and there is no timeout.
3617 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
3618 * and interrupt capability. Also see complete().
3620 void __sched wait_for_completion(struct completion *x)
3622 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
3624 EXPORT_SYMBOL(wait_for_completion);
3627 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
3628 * @x: holds the state of this particular completion
3629 * @timeout: timeout value in jiffies
3631 * This waits for either a completion of a specific task to be signaled or for a
3632 * specified timeout to expire. The timeout is in jiffies. It is not
3635 * The return value is 0 if timed out, and positive (at least 1, or number of
3636 * jiffies left till timeout) if completed.
3638 unsigned long __sched
3639 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
3641 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
3643 EXPORT_SYMBOL(wait_for_completion_timeout);
3646 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
3647 * @x: holds the state of this particular completion
3649 * This waits for completion of a specific task to be signaled. It is
3652 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3654 int __sched wait_for_completion_interruptible(struct completion *x)
3656 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
3657 if (t == -ERESTARTSYS)
3661 EXPORT_SYMBOL(wait_for_completion_interruptible);
3664 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
3665 * @x: holds the state of this particular completion
3666 * @timeout: timeout value in jiffies
3668 * This waits for either a completion of a specific task to be signaled or for a
3669 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
3671 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3672 * positive (at least 1, or number of jiffies left till timeout) if completed.
3675 wait_for_completion_interruptible_timeout(struct completion *x,
3676 unsigned long timeout)
3678 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
3680 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
3683 * wait_for_completion_killable: - waits for completion of a task (killable)
3684 * @x: holds the state of this particular completion
3686 * This waits to be signaled for completion of a specific task. It can be
3687 * interrupted by a kill signal.
3689 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3691 int __sched wait_for_completion_killable(struct completion *x)
3693 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
3694 if (t == -ERESTARTSYS)
3698 EXPORT_SYMBOL(wait_for_completion_killable);
3701 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
3702 * @x: holds the state of this particular completion
3703 * @timeout: timeout value in jiffies
3705 * This waits for either a completion of a specific task to be
3706 * signaled or for a specified timeout to expire. It can be
3707 * interrupted by a kill signal. The timeout is in jiffies.
3709 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3710 * positive (at least 1, or number of jiffies left till timeout) if completed.
3713 wait_for_completion_killable_timeout(struct completion *x,
3714 unsigned long timeout)
3716 return wait_for_common(x, timeout, TASK_KILLABLE);
3718 EXPORT_SYMBOL(wait_for_completion_killable_timeout);
3721 * try_wait_for_completion - try to decrement a completion without blocking
3722 * @x: completion structure
3724 * Returns: 0 if a decrement cannot be done without blocking
3725 * 1 if a decrement succeeded.
3727 * If a completion is being used as a counting completion,
3728 * attempt to decrement the counter without blocking. This
3729 * enables us to avoid waiting if the resource the completion
3730 * is protecting is not available.
3732 bool try_wait_for_completion(struct completion *x)
3734 unsigned long flags;
3737 spin_lock_irqsave(&x->wait.lock, flags);
3742 spin_unlock_irqrestore(&x->wait.lock, flags);
3745 EXPORT_SYMBOL(try_wait_for_completion);
3748 * completion_done - Test to see if a completion has any waiters
3749 * @x: completion structure
3751 * Returns: 0 if there are waiters (wait_for_completion() in progress)
3752 * 1 if there are no waiters.
3755 bool completion_done(struct completion *x)
3757 unsigned long flags;
3760 spin_lock_irqsave(&x->wait.lock, flags);
3763 spin_unlock_irqrestore(&x->wait.lock, flags);
3766 EXPORT_SYMBOL(completion_done);
3769 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
3771 unsigned long flags;
3774 init_waitqueue_entry(&wait, current);
3776 __set_current_state(state);
3778 spin_lock_irqsave(&q->lock, flags);
3779 __add_wait_queue(q, &wait);
3780 spin_unlock(&q->lock);
3781 timeout = schedule_timeout(timeout);
3782 spin_lock_irq(&q->lock);
3783 __remove_wait_queue(q, &wait);
3784 spin_unlock_irqrestore(&q->lock, flags);
3789 void __sched interruptible_sleep_on(wait_queue_head_t *q)
3791 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
3793 EXPORT_SYMBOL(interruptible_sleep_on);
3796 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
3798 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
3800 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
3802 void __sched sleep_on(wait_queue_head_t *q)
3804 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
3806 EXPORT_SYMBOL(sleep_on);
3808 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
3810 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
3812 EXPORT_SYMBOL(sleep_on_timeout);
3814 #ifdef CONFIG_RT_MUTEXES
3817 * rt_mutex_setprio - set the current priority of a task
3819 * @prio: prio value (kernel-internal form)
3821 * This function changes the 'effective' priority of a task. It does
3822 * not touch ->normal_prio like __setscheduler().
3824 * Used by the rt_mutex code to implement priority inheritance logic.
3826 void rt_mutex_setprio(struct task_struct *p, int prio)
3828 int oldprio, on_rq, running;
3830 const struct sched_class *prev_class;
3832 BUG_ON(prio < 0 || prio > MAX_PRIO);
3834 rq = __task_rq_lock(p);
3837 * Idle task boosting is a nono in general. There is one
3838 * exception, when PREEMPT_RT and NOHZ is active:
3840 * The idle task calls get_next_timer_interrupt() and holds
3841 * the timer wheel base->lock on the CPU and another CPU wants
3842 * to access the timer (probably to cancel it). We can safely
3843 * ignore the boosting request, as the idle CPU runs this code
3844 * with interrupts disabled and will complete the lock
3845 * protected section without being interrupted. So there is no
3846 * real need to boost.
3848 if (unlikely(p == rq->idle)) {
3849 WARN_ON(p != rq->curr);
3850 WARN_ON(p->pi_blocked_on);
3854 trace_sched_pi_setprio(p, prio);
3856 prev_class = p->sched_class;
3858 running = task_current(rq, p);
3860 dequeue_task(rq, p, 0);
3862 p->sched_class->put_prev_task(rq, p);
3865 p->sched_class = &rt_sched_class;
3867 p->sched_class = &fair_sched_class;
3872 p->sched_class->set_curr_task(rq);
3874 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
3876 check_class_changed(rq, p, prev_class, oldprio);
3878 __task_rq_unlock(rq);
3881 void set_user_nice(struct task_struct *p, long nice)
3883 int old_prio, delta, on_rq;
3884 unsigned long flags;
3887 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
3890 * We have to be careful, if called from sys_setpriority(),
3891 * the task might be in the middle of scheduling on another CPU.
3893 rq = task_rq_lock(p, &flags);
3895 * The RT priorities are set via sched_setscheduler(), but we still
3896 * allow the 'normal' nice value to be set - but as expected
3897 * it wont have any effect on scheduling until the task is
3898 * SCHED_FIFO/SCHED_RR:
3900 if (task_has_rt_policy(p)) {
3901 p->static_prio = NICE_TO_PRIO(nice);
3906 dequeue_task(rq, p, 0);
3908 p->static_prio = NICE_TO_PRIO(nice);
3911 p->prio = effective_prio(p);
3912 delta = p->prio - old_prio;
3915 enqueue_task(rq, p, 0);
3917 * If the task increased its priority or is running and
3918 * lowered its priority, then reschedule its CPU:
3920 if (delta < 0 || (delta > 0 && task_running(rq, p)))
3921 resched_task(rq->curr);
3924 task_rq_unlock(rq, p, &flags);
3926 EXPORT_SYMBOL(set_user_nice);
3929 * can_nice - check if a task can reduce its nice value
3933 int can_nice(const struct task_struct *p, const int nice)
3935 /* convert nice value [19,-20] to rlimit style value [1,40] */
3936 int nice_rlim = 20 - nice;
3938 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
3939 capable(CAP_SYS_NICE));
3942 #ifdef __ARCH_WANT_SYS_NICE
3945 * sys_nice - change the priority of the current process.
3946 * @increment: priority increment
3948 * sys_setpriority is a more generic, but much slower function that
3949 * does similar things.
3951 SYSCALL_DEFINE1(nice, int, increment)
3956 * Setpriority might change our priority at the same moment.
3957 * We don't have to worry. Conceptually one call occurs first
3958 * and we have a single winner.
3960 if (increment < -40)
3965 nice = TASK_NICE(current) + increment;
3971 if (increment < 0 && !can_nice(current, nice))
3974 retval = security_task_setnice(current, nice);
3978 set_user_nice(current, nice);
3985 * task_prio - return the priority value of a given task.
3986 * @p: the task in question.
3988 * This is the priority value as seen by users in /proc.
3989 * RT tasks are offset by -200. Normal tasks are centered
3990 * around 0, value goes from -16 to +15.
3992 int task_prio(const struct task_struct *p)
3994 return p->prio - MAX_RT_PRIO;
3998 * task_nice - return the nice value of a given task.
3999 * @p: the task in question.
4001 int task_nice(const struct task_struct *p)
4003 return TASK_NICE(p);
4005 EXPORT_SYMBOL(task_nice);
4008 * idle_cpu - is a given cpu idle currently?
4009 * @cpu: the processor in question.
4011 int idle_cpu(int cpu)
4013 struct rq *rq = cpu_rq(cpu);
4015 if (rq->curr != rq->idle)
4022 if (!llist_empty(&rq->wake_list))
4030 * idle_task - return the idle task for a given cpu.
4031 * @cpu: the processor in question.
4033 struct task_struct *idle_task(int cpu)
4035 return cpu_rq(cpu)->idle;
4039 * find_process_by_pid - find a process with a matching PID value.
4040 * @pid: the pid in question.
4042 static struct task_struct *find_process_by_pid(pid_t pid)
4044 return pid ? find_task_by_vpid(pid) : current;
4047 /* Actually do priority change: must hold rq lock. */
4049 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
4052 p->rt_priority = prio;
4053 p->normal_prio = normal_prio(p);
4054 /* we are holding p->pi_lock already */
4055 p->prio = rt_mutex_getprio(p);
4056 if (rt_prio(p->prio))
4057 p->sched_class = &rt_sched_class;
4059 p->sched_class = &fair_sched_class;
4064 * check the target process has a UID that matches the current process's
4066 static bool check_same_owner(struct task_struct *p)
4068 const struct cred *cred = current_cred(), *pcred;
4072 pcred = __task_cred(p);
4073 match = (uid_eq(cred->euid, pcred->euid) ||
4074 uid_eq(cred->euid, pcred->uid));
4079 static int __sched_setscheduler(struct task_struct *p, int policy,
4080 const struct sched_param *param, bool user)
4082 int retval, oldprio, oldpolicy = -1, on_rq, running;
4083 unsigned long flags;
4084 const struct sched_class *prev_class;
4088 /* may grab non-irq protected spin_locks */
4089 BUG_ON(in_interrupt());
4091 /* double check policy once rq lock held */
4093 reset_on_fork = p->sched_reset_on_fork;
4094 policy = oldpolicy = p->policy;
4096 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
4097 policy &= ~SCHED_RESET_ON_FORK;
4099 if (policy != SCHED_FIFO && policy != SCHED_RR &&
4100 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
4101 policy != SCHED_IDLE)
4106 * Valid priorities for SCHED_FIFO and SCHED_RR are
4107 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4108 * SCHED_BATCH and SCHED_IDLE is 0.
4110 if (param->sched_priority < 0 ||
4111 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
4112 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
4114 if (rt_policy(policy) != (param->sched_priority != 0))
4118 * Allow unprivileged RT tasks to decrease priority:
4120 if (user && !capable(CAP_SYS_NICE)) {
4121 if (rt_policy(policy)) {
4122 unsigned long rlim_rtprio =
4123 task_rlimit(p, RLIMIT_RTPRIO);
4125 /* can't set/change the rt policy */
4126 if (policy != p->policy && !rlim_rtprio)
4129 /* can't increase priority */
4130 if (param->sched_priority > p->rt_priority &&
4131 param->sched_priority > rlim_rtprio)
4136 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4137 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4139 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
4140 if (!can_nice(p, TASK_NICE(p)))
4144 /* can't change other user's priorities */
4145 if (!check_same_owner(p))
4148 /* Normal users shall not reset the sched_reset_on_fork flag */
4149 if (p->sched_reset_on_fork && !reset_on_fork)
4154 retval = security_task_setscheduler(p);
4160 * make sure no PI-waiters arrive (or leave) while we are
4161 * changing the priority of the task:
4163 * To be able to change p->policy safely, the appropriate
4164 * runqueue lock must be held.
4166 rq = task_rq_lock(p, &flags);
4169 * Changing the policy of the stop threads its a very bad idea
4171 if (p == rq->stop) {
4172 task_rq_unlock(rq, p, &flags);
4177 * If not changing anything there's no need to proceed further:
4179 if (unlikely(policy == p->policy && (!rt_policy(policy) ||
4180 param->sched_priority == p->rt_priority))) {
4182 __task_rq_unlock(rq);
4183 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4187 #ifdef CONFIG_RT_GROUP_SCHED
4190 * Do not allow realtime tasks into groups that have no runtime
4193 if (rt_bandwidth_enabled() && rt_policy(policy) &&
4194 task_group(p)->rt_bandwidth.rt_runtime == 0 &&
4195 !task_group_is_autogroup(task_group(p))) {
4196 task_rq_unlock(rq, p, &flags);
4202 /* recheck policy now with rq lock held */
4203 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
4204 policy = oldpolicy = -1;
4205 task_rq_unlock(rq, p, &flags);
4209 running = task_current(rq, p);
4211 dequeue_task(rq, p, 0);
4213 p->sched_class->put_prev_task(rq, p);
4215 p->sched_reset_on_fork = reset_on_fork;
4218 prev_class = p->sched_class;
4219 __setscheduler(rq, p, policy, param->sched_priority);
4222 p->sched_class->set_curr_task(rq);
4224 enqueue_task(rq, p, 0);
4226 check_class_changed(rq, p, prev_class, oldprio);
4227 task_rq_unlock(rq, p, &flags);
4229 rt_mutex_adjust_pi(p);
4235 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4236 * @p: the task in question.
4237 * @policy: new policy.
4238 * @param: structure containing the new RT priority.
4240 * NOTE that the task may be already dead.
4242 int sched_setscheduler(struct task_struct *p, int policy,
4243 const struct sched_param *param)
4245 return __sched_setscheduler(p, policy, param, true);
4247 EXPORT_SYMBOL_GPL(sched_setscheduler);
4250 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4251 * @p: the task in question.
4252 * @policy: new policy.
4253 * @param: structure containing the new RT priority.
4255 * Just like sched_setscheduler, only don't bother checking if the
4256 * current context has permission. For example, this is needed in
4257 * stop_machine(): we create temporary high priority worker threads,
4258 * but our caller might not have that capability.
4260 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
4261 const struct sched_param *param)
4263 return __sched_setscheduler(p, policy, param, false);
4267 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
4269 struct sched_param lparam;
4270 struct task_struct *p;
4273 if (!param || pid < 0)
4275 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
4280 p = find_process_by_pid(pid);
4282 retval = sched_setscheduler(p, policy, &lparam);
4289 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4290 * @pid: the pid in question.
4291 * @policy: new policy.
4292 * @param: structure containing the new RT priority.
4294 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
4295 struct sched_param __user *, param)
4297 /* negative values for policy are not valid */
4301 return do_sched_setscheduler(pid, policy, param);
4305 * sys_sched_setparam - set/change the RT priority of a thread
4306 * @pid: the pid in question.
4307 * @param: structure containing the new RT priority.
4309 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
4311 return do_sched_setscheduler(pid, -1, param);
4315 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4316 * @pid: the pid in question.
4318 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
4320 struct task_struct *p;
4328 p = find_process_by_pid(pid);
4330 retval = security_task_getscheduler(p);
4333 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
4340 * sys_sched_getparam - get the RT priority of a thread
4341 * @pid: the pid in question.
4342 * @param: structure containing the RT priority.
4344 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
4346 struct sched_param lp;
4347 struct task_struct *p;
4350 if (!param || pid < 0)
4354 p = find_process_by_pid(pid);
4359 retval = security_task_getscheduler(p);
4363 lp.sched_priority = p->rt_priority;
4367 * This one might sleep, we cannot do it with a spinlock held ...
4369 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
4378 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
4380 cpumask_var_t cpus_allowed, new_mask;
4381 struct task_struct *p;
4387 p = find_process_by_pid(pid);
4394 /* Prevent p going away */
4398 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
4402 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
4404 goto out_free_cpus_allowed;
4407 if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE))
4410 retval = security_task_setscheduler(p);
4414 cpuset_cpus_allowed(p, cpus_allowed);
4415 cpumask_and(new_mask, in_mask, cpus_allowed);
4417 retval = set_cpus_allowed_ptr(p, new_mask);
4420 cpuset_cpus_allowed(p, cpus_allowed);
4421 if (!cpumask_subset(new_mask, cpus_allowed)) {
4423 * We must have raced with a concurrent cpuset
4424 * update. Just reset the cpus_allowed to the
4425 * cpuset's cpus_allowed
4427 cpumask_copy(new_mask, cpus_allowed);
4432 free_cpumask_var(new_mask);
4433 out_free_cpus_allowed:
4434 free_cpumask_var(cpus_allowed);
4441 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
4442 struct cpumask *new_mask)
4444 if (len < cpumask_size())
4445 cpumask_clear(new_mask);
4446 else if (len > cpumask_size())
4447 len = cpumask_size();
4449 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
4453 * sys_sched_setaffinity - set the cpu affinity of a process
4454 * @pid: pid of the process
4455 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4456 * @user_mask_ptr: user-space pointer to the new cpu mask
4458 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
4459 unsigned long __user *, user_mask_ptr)
4461 cpumask_var_t new_mask;
4464 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
4467 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
4469 retval = sched_setaffinity(pid, new_mask);
4470 free_cpumask_var(new_mask);
4474 long sched_getaffinity(pid_t pid, struct cpumask *mask)
4476 struct task_struct *p;
4477 unsigned long flags;
4484 p = find_process_by_pid(pid);
4488 retval = security_task_getscheduler(p);
4492 raw_spin_lock_irqsave(&p->pi_lock, flags);
4493 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
4494 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4504 * sys_sched_getaffinity - get the cpu affinity of a process
4505 * @pid: pid of the process
4506 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4507 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4509 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
4510 unsigned long __user *, user_mask_ptr)
4515 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
4517 if (len & (sizeof(unsigned long)-1))
4520 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
4523 ret = sched_getaffinity(pid, mask);
4525 size_t retlen = min_t(size_t, len, cpumask_size());
4527 if (copy_to_user(user_mask_ptr, mask, retlen))
4532 free_cpumask_var(mask);
4538 * sys_sched_yield - yield the current processor to other threads.
4540 * This function yields the current CPU to other tasks. If there are no
4541 * other threads running on this CPU then this function will return.
4543 SYSCALL_DEFINE0(sched_yield)
4545 struct rq *rq = this_rq_lock();
4547 schedstat_inc(rq, yld_count);
4548 current->sched_class->yield_task(rq);
4551 * Since we are going to call schedule() anyway, there's
4552 * no need to preempt or enable interrupts:
4554 __release(rq->lock);
4555 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
4556 do_raw_spin_unlock(&rq->lock);
4557 sched_preempt_enable_no_resched();
4564 static inline int should_resched(void)
4566 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
4569 static void __cond_resched(void)
4571 add_preempt_count(PREEMPT_ACTIVE);
4573 sub_preempt_count(PREEMPT_ACTIVE);
4576 int __sched _cond_resched(void)
4578 if (should_resched()) {
4584 EXPORT_SYMBOL(_cond_resched);
4587 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4588 * call schedule, and on return reacquire the lock.
4590 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4591 * operations here to prevent schedule() from being called twice (once via
4592 * spin_unlock(), once by hand).
4594 int __cond_resched_lock(spinlock_t *lock)
4596 int resched = should_resched();
4599 lockdep_assert_held(lock);
4601 if (spin_needbreak(lock) || resched) {
4612 EXPORT_SYMBOL(__cond_resched_lock);
4614 int __sched __cond_resched_softirq(void)
4616 BUG_ON(!in_softirq());
4618 if (should_resched()) {
4626 EXPORT_SYMBOL(__cond_resched_softirq);
4629 * yield - yield the current processor to other threads.
4631 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4633 * The scheduler is at all times free to pick the calling task as the most
4634 * eligible task to run, if removing the yield() call from your code breaks
4635 * it, its already broken.
4637 * Typical broken usage is:
4642 * where one assumes that yield() will let 'the other' process run that will
4643 * make event true. If the current task is a SCHED_FIFO task that will never
4644 * happen. Never use yield() as a progress guarantee!!
4646 * If you want to use yield() to wait for something, use wait_event().
4647 * If you want to use yield() to be 'nice' for others, use cond_resched().
4648 * If you still want to use yield(), do not!
4650 void __sched yield(void)
4652 set_current_state(TASK_RUNNING);
4655 EXPORT_SYMBOL(yield);
4658 * yield_to - yield the current processor to another thread in
4659 * your thread group, or accelerate that thread toward the
4660 * processor it's on.
4662 * @preempt: whether task preemption is allowed or not
4664 * It's the caller's job to ensure that the target task struct
4665 * can't go away on us before we can do any checks.
4667 * Returns true if we indeed boosted the target task.
4669 bool __sched yield_to(struct task_struct *p, bool preempt)
4671 struct task_struct *curr = current;
4672 struct rq *rq, *p_rq;
4673 unsigned long flags;
4676 local_irq_save(flags);
4681 double_rq_lock(rq, p_rq);
4682 while (task_rq(p) != p_rq) {
4683 double_rq_unlock(rq, p_rq);
4687 if (!curr->sched_class->yield_to_task)
4690 if (curr->sched_class != p->sched_class)
4693 if (task_running(p_rq, p) || p->state)
4696 yielded = curr->sched_class->yield_to_task(rq, p, preempt);
4698 schedstat_inc(rq, yld_count);
4700 * Make p's CPU reschedule; pick_next_entity takes care of
4703 if (preempt && rq != p_rq)
4704 resched_task(p_rq->curr);
4707 * We might have set it in task_yield_fair(), but are
4708 * not going to schedule(), so don't want to skip
4711 rq->skip_clock_update = 0;
4715 double_rq_unlock(rq, p_rq);
4716 local_irq_restore(flags);
4723 EXPORT_SYMBOL_GPL(yield_to);
4726 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4727 * that process accounting knows that this is a task in IO wait state.
4729 void __sched io_schedule(void)
4731 struct rq *rq = raw_rq();
4733 delayacct_blkio_start();
4734 atomic_inc(&rq->nr_iowait);
4735 blk_flush_plug(current);
4736 current->in_iowait = 1;
4738 current->in_iowait = 0;
4739 atomic_dec(&rq->nr_iowait);
4740 delayacct_blkio_end();
4742 EXPORT_SYMBOL(io_schedule);
4744 long __sched io_schedule_timeout(long timeout)
4746 struct rq *rq = raw_rq();
4749 delayacct_blkio_start();
4750 atomic_inc(&rq->nr_iowait);
4751 blk_flush_plug(current);
4752 current->in_iowait = 1;
4753 ret = schedule_timeout(timeout);
4754 current->in_iowait = 0;
4755 atomic_dec(&rq->nr_iowait);
4756 delayacct_blkio_end();
4761 * sys_sched_get_priority_max - return maximum RT priority.
4762 * @policy: scheduling class.
4764 * this syscall returns the maximum rt_priority that can be used
4765 * by a given scheduling class.
4767 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
4774 ret = MAX_USER_RT_PRIO-1;
4786 * sys_sched_get_priority_min - return minimum RT priority.
4787 * @policy: scheduling class.
4789 * this syscall returns the minimum rt_priority that can be used
4790 * by a given scheduling class.
4792 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
4810 * sys_sched_rr_get_interval - return the default timeslice of a process.
4811 * @pid: pid of the process.
4812 * @interval: userspace pointer to the timeslice value.
4814 * this syscall writes the default timeslice value of a given process
4815 * into the user-space timespec buffer. A value of '0' means infinity.
4817 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
4818 struct timespec __user *, interval)
4820 struct task_struct *p;
4821 unsigned int time_slice;
4822 unsigned long flags;
4832 p = find_process_by_pid(pid);
4836 retval = security_task_getscheduler(p);
4840 rq = task_rq_lock(p, &flags);
4841 time_slice = p->sched_class->get_rr_interval(rq, p);
4842 task_rq_unlock(rq, p, &flags);
4845 jiffies_to_timespec(time_slice, &t);
4846 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
4854 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
4856 void sched_show_task(struct task_struct *p)
4858 unsigned long free = 0;
4861 state = p->state ? __ffs(p->state) + 1 : 0;
4862 printk(KERN_INFO "%-15.15s %c", p->comm,
4863 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
4864 #if BITS_PER_LONG == 32
4865 if (state == TASK_RUNNING)
4866 printk(KERN_CONT " running ");
4868 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
4870 if (state == TASK_RUNNING)
4871 printk(KERN_CONT " running task ");
4873 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
4875 #ifdef CONFIG_DEBUG_STACK_USAGE
4876 free = stack_not_used(p);
4878 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
4879 task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)),
4880 (unsigned long)task_thread_info(p)->flags);
4882 show_stack(p, NULL);
4885 void show_state_filter(unsigned long state_filter)
4887 struct task_struct *g, *p;
4889 #if BITS_PER_LONG == 32
4891 " task PC stack pid father\n");
4894 " task PC stack pid father\n");
4897 do_each_thread(g, p) {
4899 * reset the NMI-timeout, listing all files on a slow
4900 * console might take a lot of time:
4902 touch_nmi_watchdog();
4903 if (!state_filter || (p->state & state_filter))
4905 } while_each_thread(g, p);
4907 touch_all_softlockup_watchdogs();
4909 #ifdef CONFIG_SCHED_DEBUG
4910 sysrq_sched_debug_show();
4914 * Only show locks if all tasks are dumped:
4917 debug_show_all_locks();
4920 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
4922 idle->sched_class = &idle_sched_class;
4926 * init_idle - set up an idle thread for a given CPU
4927 * @idle: task in question
4928 * @cpu: cpu the idle task belongs to
4930 * NOTE: this function does not set the idle thread's NEED_RESCHED
4931 * flag, to make booting more robust.
4933 void __cpuinit init_idle(struct task_struct *idle, int cpu)
4935 struct rq *rq = cpu_rq(cpu);
4936 unsigned long flags;
4938 raw_spin_lock_irqsave(&rq->lock, flags);
4941 idle->state = TASK_RUNNING;
4942 idle->se.exec_start = sched_clock();
4944 do_set_cpus_allowed(idle, cpumask_of(cpu));
4946 * We're having a chicken and egg problem, even though we are
4947 * holding rq->lock, the cpu isn't yet set to this cpu so the
4948 * lockdep check in task_group() will fail.
4950 * Similar case to sched_fork(). / Alternatively we could
4951 * use task_rq_lock() here and obtain the other rq->lock.
4956 __set_task_cpu(idle, cpu);
4959 rq->curr = rq->idle = idle;
4960 #if defined(CONFIG_SMP)
4963 raw_spin_unlock_irqrestore(&rq->lock, flags);
4965 /* Set the preempt count _outside_ the spinlocks! */
4966 task_thread_info(idle)->preempt_count = 0;
4969 * The idle tasks have their own, simple scheduling class:
4971 idle->sched_class = &idle_sched_class;
4972 ftrace_graph_init_idle_task(idle, cpu);
4973 #if defined(CONFIG_SMP)
4974 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
4979 void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
4981 if (p->sched_class && p->sched_class->set_cpus_allowed)
4982 p->sched_class->set_cpus_allowed(p, new_mask);
4984 cpumask_copy(&p->cpus_allowed, new_mask);
4985 p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
4989 * This is how migration works:
4991 * 1) we invoke migration_cpu_stop() on the target CPU using
4993 * 2) stopper starts to run (implicitly forcing the migrated thread
4995 * 3) it checks whether the migrated task is still in the wrong runqueue.
4996 * 4) if it's in the wrong runqueue then the migration thread removes
4997 * it and puts it into the right queue.
4998 * 5) stopper completes and stop_one_cpu() returns and the migration
5003 * Change a given task's CPU affinity. Migrate the thread to a
5004 * proper CPU and schedule it away if the CPU it's executing on
5005 * is removed from the allowed bitmask.
5007 * NOTE: the caller must have a valid reference to the task, the
5008 * task must not exit() & deallocate itself prematurely. The
5009 * call is not atomic; no spinlocks may be held.
5011 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
5013 unsigned long flags;
5015 unsigned int dest_cpu;
5018 rq = task_rq_lock(p, &flags);
5020 if (cpumask_equal(&p->cpus_allowed, new_mask))
5023 if (!cpumask_intersects(new_mask, cpu_active_mask)) {
5028 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) {
5033 do_set_cpus_allowed(p, new_mask);
5035 /* Can the task run on the task's current CPU? If so, we're done */
5036 if (cpumask_test_cpu(task_cpu(p), new_mask))
5039 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
5041 struct migration_arg arg = { p, dest_cpu };
5042 /* Need help from migration thread: drop lock and wait. */
5043 task_rq_unlock(rq, p, &flags);
5044 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
5045 tlb_migrate_finish(p->mm);
5049 task_rq_unlock(rq, p, &flags);
5053 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
5056 * Move (not current) task off this cpu, onto dest cpu. We're doing
5057 * this because either it can't run here any more (set_cpus_allowed()
5058 * away from this CPU, or CPU going down), or because we're
5059 * attempting to rebalance this task on exec (sched_exec).
5061 * So we race with normal scheduler movements, but that's OK, as long
5062 * as the task is no longer on this CPU.
5064 * Returns non-zero if task was successfully migrated.
5066 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
5068 struct rq *rq_dest, *rq_src;
5071 if (unlikely(!cpu_active(dest_cpu)))
5074 rq_src = cpu_rq(src_cpu);
5075 rq_dest = cpu_rq(dest_cpu);
5077 raw_spin_lock(&p->pi_lock);
5078 double_rq_lock(rq_src, rq_dest);
5079 /* Already moved. */
5080 if (task_cpu(p) != src_cpu)
5082 /* Affinity changed (again). */
5083 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
5087 * If we're not on a rq, the next wake-up will ensure we're
5091 dequeue_task(rq_src, p, 0);
5092 set_task_cpu(p, dest_cpu);
5093 enqueue_task(rq_dest, p, 0);
5094 check_preempt_curr(rq_dest, p, 0);
5099 double_rq_unlock(rq_src, rq_dest);
5100 raw_spin_unlock(&p->pi_lock);
5105 * migration_cpu_stop - this will be executed by a highprio stopper thread
5106 * and performs thread migration by bumping thread off CPU then
5107 * 'pushing' onto another runqueue.
5109 static int migration_cpu_stop(void *data)
5111 struct migration_arg *arg = data;
5114 * The original target cpu might have gone down and we might
5115 * be on another cpu but it doesn't matter.
5117 local_irq_disable();
5118 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
5123 #ifdef CONFIG_HOTPLUG_CPU
5126 * Ensures that the idle task is using init_mm right before its cpu goes
5129 void idle_task_exit(void)
5131 struct mm_struct *mm = current->active_mm;
5133 BUG_ON(cpu_online(smp_processor_id()));
5136 switch_mm(mm, &init_mm, current);
5141 * While a dead CPU has no uninterruptible tasks queued at this point,
5142 * it might still have a nonzero ->nr_uninterruptible counter, because
5143 * for performance reasons the counter is not stricly tracking tasks to
5144 * their home CPUs. So we just add the counter to another CPU's counter,
5145 * to keep the global sum constant after CPU-down:
5147 static void migrate_nr_uninterruptible(struct rq *rq_src)
5149 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
5151 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
5152 rq_src->nr_uninterruptible = 0;
5156 * remove the tasks which were accounted by rq from calc_load_tasks.
5158 static void calc_global_load_remove(struct rq *rq)
5160 atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
5161 rq->calc_load_active = 0;
5165 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5166 * try_to_wake_up()->select_task_rq().
5168 * Called with rq->lock held even though we'er in stop_machine() and
5169 * there's no concurrency possible, we hold the required locks anyway
5170 * because of lock validation efforts.
5172 static void migrate_tasks(unsigned int dead_cpu)
5174 struct rq *rq = cpu_rq(dead_cpu);
5175 struct task_struct *next, *stop = rq->stop;
5179 * Fudge the rq selection such that the below task selection loop
5180 * doesn't get stuck on the currently eligible stop task.
5182 * We're currently inside stop_machine() and the rq is either stuck
5183 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5184 * either way we should never end up calling schedule() until we're
5189 /* Ensure any throttled groups are reachable by pick_next_task */
5190 unthrottle_offline_cfs_rqs(rq);
5194 * There's this thread running, bail when that's the only
5197 if (rq->nr_running == 1)
5200 next = pick_next_task(rq);
5202 next->sched_class->put_prev_task(rq, next);
5204 /* Find suitable destination for @next, with force if needed. */
5205 dest_cpu = select_fallback_rq(dead_cpu, next);
5206 raw_spin_unlock(&rq->lock);
5208 __migrate_task(next, dead_cpu, dest_cpu);
5210 raw_spin_lock(&rq->lock);
5216 #endif /* CONFIG_HOTPLUG_CPU */
5218 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5220 static struct ctl_table sd_ctl_dir[] = {
5222 .procname = "sched_domain",
5228 static struct ctl_table sd_ctl_root[] = {
5230 .procname = "kernel",
5232 .child = sd_ctl_dir,
5237 static struct ctl_table *sd_alloc_ctl_entry(int n)
5239 struct ctl_table *entry =
5240 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
5245 static void sd_free_ctl_entry(struct ctl_table **tablep)
5247 struct ctl_table *entry;
5250 * In the intermediate directories, both the child directory and
5251 * procname are dynamically allocated and could fail but the mode
5252 * will always be set. In the lowest directory the names are
5253 * static strings and all have proc handlers.
5255 for (entry = *tablep; entry->mode; entry++) {
5257 sd_free_ctl_entry(&entry->child);
5258 if (entry->proc_handler == NULL)
5259 kfree(entry->procname);
5267 set_table_entry(struct ctl_table *entry,
5268 const char *procname, void *data, int maxlen,
5269 umode_t mode, proc_handler *proc_handler)
5271 entry->procname = procname;
5273 entry->maxlen = maxlen;
5275 entry->proc_handler = proc_handler;
5278 static struct ctl_table *
5279 sd_alloc_ctl_domain_table(struct sched_domain *sd)
5281 struct ctl_table *table = sd_alloc_ctl_entry(13);
5286 set_table_entry(&table[0], "min_interval", &sd->min_interval,
5287 sizeof(long), 0644, proc_doulongvec_minmax);
5288 set_table_entry(&table[1], "max_interval", &sd->max_interval,
5289 sizeof(long), 0644, proc_doulongvec_minmax);
5290 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
5291 sizeof(int), 0644, proc_dointvec_minmax);
5292 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
5293 sizeof(int), 0644, proc_dointvec_minmax);
5294 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
5295 sizeof(int), 0644, proc_dointvec_minmax);
5296 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
5297 sizeof(int), 0644, proc_dointvec_minmax);
5298 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
5299 sizeof(int), 0644, proc_dointvec_minmax);
5300 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
5301 sizeof(int), 0644, proc_dointvec_minmax);
5302 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
5303 sizeof(int), 0644, proc_dointvec_minmax);
5304 set_table_entry(&table[9], "cache_nice_tries",
5305 &sd->cache_nice_tries,
5306 sizeof(int), 0644, proc_dointvec_minmax);
5307 set_table_entry(&table[10], "flags", &sd->flags,
5308 sizeof(int), 0644, proc_dointvec_minmax);
5309 set_table_entry(&table[11], "name", sd->name,
5310 CORENAME_MAX_SIZE, 0444, proc_dostring);
5311 /* &table[12] is terminator */
5316 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
5318 struct ctl_table *entry, *table;
5319 struct sched_domain *sd;
5320 int domain_num = 0, i;
5323 for_each_domain(cpu, sd)
5325 entry = table = sd_alloc_ctl_entry(domain_num + 1);
5330 for_each_domain(cpu, sd) {
5331 snprintf(buf, 32, "domain%d", i);
5332 entry->procname = kstrdup(buf, GFP_KERNEL);
5334 entry->child = sd_alloc_ctl_domain_table(sd);
5341 static struct ctl_table_header *sd_sysctl_header;
5342 static void register_sched_domain_sysctl(void)
5344 int i, cpu_num = num_possible_cpus();
5345 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
5348 WARN_ON(sd_ctl_dir[0].child);
5349 sd_ctl_dir[0].child = entry;
5354 for_each_possible_cpu(i) {
5355 snprintf(buf, 32, "cpu%d", i);
5356 entry->procname = kstrdup(buf, GFP_KERNEL);
5358 entry->child = sd_alloc_ctl_cpu_table(i);
5362 WARN_ON(sd_sysctl_header);
5363 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
5366 /* may be called multiple times per register */
5367 static void unregister_sched_domain_sysctl(void)
5369 if (sd_sysctl_header)
5370 unregister_sysctl_table(sd_sysctl_header);
5371 sd_sysctl_header = NULL;
5372 if (sd_ctl_dir[0].child)
5373 sd_free_ctl_entry(&sd_ctl_dir[0].child);
5376 static void register_sched_domain_sysctl(void)
5379 static void unregister_sched_domain_sysctl(void)
5384 static void set_rq_online(struct rq *rq)
5387 const struct sched_class *class;
5389 cpumask_set_cpu(rq->cpu, rq->rd->online);
5392 for_each_class(class) {
5393 if (class->rq_online)
5394 class->rq_online(rq);
5399 static void set_rq_offline(struct rq *rq)
5402 const struct sched_class *class;
5404 for_each_class(class) {
5405 if (class->rq_offline)
5406 class->rq_offline(rq);
5409 cpumask_clear_cpu(rq->cpu, rq->rd->online);
5415 * migration_call - callback that gets triggered when a CPU is added.
5416 * Here we can start up the necessary migration thread for the new CPU.
5418 static int __cpuinit
5419 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
5421 int cpu = (long)hcpu;
5422 unsigned long flags;
5423 struct rq *rq = cpu_rq(cpu);
5425 switch (action & ~CPU_TASKS_FROZEN) {
5427 case CPU_UP_PREPARE:
5428 rq->calc_load_update = calc_load_update;
5432 /* Update our root-domain */
5433 raw_spin_lock_irqsave(&rq->lock, flags);
5435 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5439 raw_spin_unlock_irqrestore(&rq->lock, flags);
5442 #ifdef CONFIG_HOTPLUG_CPU
5444 sched_ttwu_pending();
5445 /* Update our root-domain */
5446 raw_spin_lock_irqsave(&rq->lock, flags);
5448 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5452 BUG_ON(rq->nr_running != 1); /* the migration thread */
5453 raw_spin_unlock_irqrestore(&rq->lock, flags);
5455 migrate_nr_uninterruptible(rq);
5456 calc_global_load_remove(rq);
5461 update_max_interval();
5467 * Register at high priority so that task migration (migrate_all_tasks)
5468 * happens before everything else. This has to be lower priority than
5469 * the notifier in the perf_event subsystem, though.
5471 static struct notifier_block __cpuinitdata migration_notifier = {
5472 .notifier_call = migration_call,
5473 .priority = CPU_PRI_MIGRATION,
5476 static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
5477 unsigned long action, void *hcpu)
5479 switch (action & ~CPU_TASKS_FROZEN) {
5481 case CPU_DOWN_FAILED:
5482 set_cpu_active((long)hcpu, true);
5489 static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
5490 unsigned long action, void *hcpu)
5492 switch (action & ~CPU_TASKS_FROZEN) {
5493 case CPU_DOWN_PREPARE:
5494 set_cpu_active((long)hcpu, false);
5501 static int __init migration_init(void)
5503 void *cpu = (void *)(long)smp_processor_id();
5506 /* Initialize migration for the boot CPU */
5507 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
5508 BUG_ON(err == NOTIFY_BAD);
5509 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5510 register_cpu_notifier(&migration_notifier);
5512 /* Register cpu active notifiers */
5513 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
5514 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
5518 early_initcall(migration_init);
5523 static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
5525 #ifdef CONFIG_SCHED_DEBUG
5527 static __read_mostly int sched_domain_debug_enabled;
5529 static int __init sched_domain_debug_setup(char *str)
5531 sched_domain_debug_enabled = 1;
5535 early_param("sched_debug", sched_domain_debug_setup);
5537 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
5538 struct cpumask *groupmask)
5540 struct sched_group *group = sd->groups;
5543 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
5544 cpumask_clear(groupmask);
5546 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
5548 if (!(sd->flags & SD_LOAD_BALANCE)) {
5549 printk("does not load-balance\n");
5551 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
5556 printk(KERN_CONT "span %s level %s\n", str, sd->name);
5558 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
5559 printk(KERN_ERR "ERROR: domain->span does not contain "
5562 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
5563 printk(KERN_ERR "ERROR: domain->groups does not contain"
5567 printk(KERN_DEBUG "%*s groups:", level + 1, "");
5571 printk(KERN_ERR "ERROR: group is NULL\n");
5575 if (!group->sgp->power) {
5576 printk(KERN_CONT "\n");
5577 printk(KERN_ERR "ERROR: domain->cpu_power not "
5582 if (!cpumask_weight(sched_group_cpus(group))) {
5583 printk(KERN_CONT "\n");
5584 printk(KERN_ERR "ERROR: empty group\n");
5588 if (!(sd->flags & SD_OVERLAP) &&
5589 cpumask_intersects(groupmask, sched_group_cpus(group))) {
5590 printk(KERN_CONT "\n");
5591 printk(KERN_ERR "ERROR: repeated CPUs\n");
5595 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
5597 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
5599 printk(KERN_CONT " %s", str);
5600 if (group->sgp->power != SCHED_POWER_SCALE) {
5601 printk(KERN_CONT " (cpu_power = %d)",
5605 group = group->next;
5606 } while (group != sd->groups);
5607 printk(KERN_CONT "\n");
5609 if (!cpumask_equal(sched_domain_span(sd), groupmask))
5610 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
5613 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
5614 printk(KERN_ERR "ERROR: parent span is not a superset "
5615 "of domain->span\n");
5619 static void sched_domain_debug(struct sched_domain *sd, int cpu)
5623 if (!sched_domain_debug_enabled)
5627 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
5631 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
5634 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
5642 #else /* !CONFIG_SCHED_DEBUG */
5643 # define sched_domain_debug(sd, cpu) do { } while (0)
5644 #endif /* CONFIG_SCHED_DEBUG */
5646 static int sd_degenerate(struct sched_domain *sd)
5648 if (cpumask_weight(sched_domain_span(sd)) == 1)
5651 /* Following flags need at least 2 groups */
5652 if (sd->flags & (SD_LOAD_BALANCE |
5653 SD_BALANCE_NEWIDLE |
5657 SD_SHARE_PKG_RESOURCES)) {
5658 if (sd->groups != sd->groups->next)
5662 /* Following flags don't use groups */
5663 if (sd->flags & (SD_WAKE_AFFINE))
5670 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
5672 unsigned long cflags = sd->flags, pflags = parent->flags;
5674 if (sd_degenerate(parent))
5677 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
5680 /* Flags needing groups don't count if only 1 group in parent */
5681 if (parent->groups == parent->groups->next) {
5682 pflags &= ~(SD_LOAD_BALANCE |
5683 SD_BALANCE_NEWIDLE |
5687 SD_SHARE_PKG_RESOURCES);
5688 if (nr_node_ids == 1)
5689 pflags &= ~SD_SERIALIZE;
5691 if (~cflags & pflags)
5697 static void free_rootdomain(struct rcu_head *rcu)
5699 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
5701 cpupri_cleanup(&rd->cpupri);
5702 free_cpumask_var(rd->rto_mask);
5703 free_cpumask_var(rd->online);
5704 free_cpumask_var(rd->span);
5708 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
5710 struct root_domain *old_rd = NULL;
5711 unsigned long flags;
5713 raw_spin_lock_irqsave(&rq->lock, flags);
5718 if (cpumask_test_cpu(rq->cpu, old_rd->online))
5721 cpumask_clear_cpu(rq->cpu, old_rd->span);
5724 * If we dont want to free the old_rt yet then
5725 * set old_rd to NULL to skip the freeing later
5728 if (!atomic_dec_and_test(&old_rd->refcount))
5732 atomic_inc(&rd->refcount);
5735 cpumask_set_cpu(rq->cpu, rd->span);
5736 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
5739 raw_spin_unlock_irqrestore(&rq->lock, flags);
5742 call_rcu_sched(&old_rd->rcu, free_rootdomain);
5745 static int init_rootdomain(struct root_domain *rd)
5747 memset(rd, 0, sizeof(*rd));
5749 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
5751 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
5753 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
5756 if (cpupri_init(&rd->cpupri) != 0)
5761 free_cpumask_var(rd->rto_mask);
5763 free_cpumask_var(rd->online);
5765 free_cpumask_var(rd->span);
5771 * By default the system creates a single root-domain with all cpus as
5772 * members (mimicking the global state we have today).
5774 struct root_domain def_root_domain;
5776 static void init_defrootdomain(void)
5778 init_rootdomain(&def_root_domain);
5780 atomic_set(&def_root_domain.refcount, 1);
5783 static struct root_domain *alloc_rootdomain(void)
5785 struct root_domain *rd;
5787 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
5791 if (init_rootdomain(rd) != 0) {
5799 static void free_sched_groups(struct sched_group *sg, int free_sgp)
5801 struct sched_group *tmp, *first;
5810 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref))
5815 } while (sg != first);
5818 static void free_sched_domain(struct rcu_head *rcu)
5820 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
5823 * If its an overlapping domain it has private groups, iterate and
5826 if (sd->flags & SD_OVERLAP) {
5827 free_sched_groups(sd->groups, 1);
5828 } else if (atomic_dec_and_test(&sd->groups->ref)) {
5829 kfree(sd->groups->sgp);
5835 static void destroy_sched_domain(struct sched_domain *sd, int cpu)
5837 call_rcu(&sd->rcu, free_sched_domain);
5840 static void destroy_sched_domains(struct sched_domain *sd, int cpu)
5842 for (; sd; sd = sd->parent)
5843 destroy_sched_domain(sd, cpu);
5847 * Keep a special pointer to the highest sched_domain that has
5848 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5849 * allows us to avoid some pointer chasing select_idle_sibling().
5851 * Also keep a unique ID per domain (we use the first cpu number in
5852 * the cpumask of the domain), this allows us to quickly tell if
5853 * two cpus are in the same cache domain, see cpus_share_cache().
5855 DEFINE_PER_CPU(struct sched_domain *, sd_llc);
5856 DEFINE_PER_CPU(int, sd_llc_id);
5858 static void update_top_cache_domain(int cpu)
5860 struct sched_domain *sd;
5863 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
5865 id = cpumask_first(sched_domain_span(sd));
5867 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
5868 per_cpu(sd_llc_id, cpu) = id;
5872 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5873 * hold the hotplug lock.
5876 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
5878 struct rq *rq = cpu_rq(cpu);
5879 struct sched_domain *tmp;
5881 /* Remove the sched domains which do not contribute to scheduling. */
5882 for (tmp = sd; tmp; ) {
5883 struct sched_domain *parent = tmp->parent;
5887 if (sd_parent_degenerate(tmp, parent)) {
5888 tmp->parent = parent->parent;
5890 parent->parent->child = tmp;
5891 destroy_sched_domain(parent, cpu);
5896 if (sd && sd_degenerate(sd)) {
5899 destroy_sched_domain(tmp, cpu);
5904 sched_domain_debug(sd, cpu);
5906 rq_attach_root(rq, rd);
5908 rcu_assign_pointer(rq->sd, sd);
5909 destroy_sched_domains(tmp, cpu);
5911 update_top_cache_domain(cpu);
5914 /* cpus with isolated domains */
5915 static cpumask_var_t cpu_isolated_map;
5917 /* Setup the mask of cpus configured for isolated domains */
5918 static int __init isolated_cpu_setup(char *str)
5920 alloc_bootmem_cpumask_var(&cpu_isolated_map);
5921 cpulist_parse(str, cpu_isolated_map);
5925 __setup("isolcpus=", isolated_cpu_setup);
5927 static const struct cpumask *cpu_cpu_mask(int cpu)
5929 return cpumask_of_node(cpu_to_node(cpu));
5933 struct sched_domain **__percpu sd;
5934 struct sched_group **__percpu sg;
5935 struct sched_group_power **__percpu sgp;
5939 struct sched_domain ** __percpu sd;
5940 struct root_domain *rd;
5950 struct sched_domain_topology_level;
5952 typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
5953 typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
5955 #define SDTL_OVERLAP 0x01
5957 struct sched_domain_topology_level {
5958 sched_domain_init_f init;
5959 sched_domain_mask_f mask;
5962 struct sd_data data;
5966 build_overlap_sched_groups(struct sched_domain *sd, int cpu)
5968 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
5969 const struct cpumask *span = sched_domain_span(sd);
5970 struct cpumask *covered = sched_domains_tmpmask;
5971 struct sd_data *sdd = sd->private;
5972 struct sched_domain *child;
5975 cpumask_clear(covered);
5977 for_each_cpu(i, span) {
5978 struct cpumask *sg_span;
5980 if (cpumask_test_cpu(i, covered))
5983 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
5984 GFP_KERNEL, cpu_to_node(cpu));
5989 sg_span = sched_group_cpus(sg);
5991 child = *per_cpu_ptr(sdd->sd, i);
5993 child = child->child;
5994 cpumask_copy(sg_span, sched_domain_span(child));
5996 cpumask_set_cpu(i, sg_span);
5998 cpumask_or(covered, covered, sg_span);
6000 sg->sgp = *per_cpu_ptr(sdd->sgp, cpumask_first(sg_span));
6001 atomic_inc(&sg->sgp->ref);
6003 if (cpumask_test_cpu(cpu, sg_span))
6013 sd->groups = groups;
6018 free_sched_groups(first, 0);
6023 static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
6025 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
6026 struct sched_domain *child = sd->child;
6029 cpu = cpumask_first(sched_domain_span(child));
6032 *sg = *per_cpu_ptr(sdd->sg, cpu);
6033 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu);
6034 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */
6041 * build_sched_groups will build a circular linked list of the groups
6042 * covered by the given span, and will set each group's ->cpumask correctly,
6043 * and ->cpu_power to 0.
6045 * Assumes the sched_domain tree is fully constructed
6048 build_sched_groups(struct sched_domain *sd, int cpu)
6050 struct sched_group *first = NULL, *last = NULL;
6051 struct sd_data *sdd = sd->private;
6052 const struct cpumask *span = sched_domain_span(sd);
6053 struct cpumask *covered;
6056 get_group(cpu, sdd, &sd->groups);
6057 atomic_inc(&sd->groups->ref);
6059 if (cpu != cpumask_first(sched_domain_span(sd)))
6062 lockdep_assert_held(&sched_domains_mutex);
6063 covered = sched_domains_tmpmask;
6065 cpumask_clear(covered);
6067 for_each_cpu(i, span) {
6068 struct sched_group *sg;
6069 int group = get_group(i, sdd, &sg);
6072 if (cpumask_test_cpu(i, covered))
6075 cpumask_clear(sched_group_cpus(sg));
6078 for_each_cpu(j, span) {
6079 if (get_group(j, sdd, NULL) != group)
6082 cpumask_set_cpu(j, covered);
6083 cpumask_set_cpu(j, sched_group_cpus(sg));
6098 * Initialize sched groups cpu_power.
6100 * cpu_power indicates the capacity of sched group, which is used while
6101 * distributing the load between different sched groups in a sched domain.
6102 * Typically cpu_power for all the groups in a sched domain will be same unless
6103 * there are asymmetries in the topology. If there are asymmetries, group
6104 * having more cpu_power will pickup more load compared to the group having
6107 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
6109 struct sched_group *sg = sd->groups;
6111 WARN_ON(!sd || !sg);
6114 sg->group_weight = cpumask_weight(sched_group_cpus(sg));
6116 } while (sg != sd->groups);
6118 if (cpu != group_first_cpu(sg))
6121 update_group_power(sd, cpu);
6122 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
6125 int __weak arch_sd_sibling_asym_packing(void)
6127 return 0*SD_ASYM_PACKING;
6131 * Initializers for schedule domains
6132 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6135 #ifdef CONFIG_SCHED_DEBUG
6136 # define SD_INIT_NAME(sd, type) sd->name = #type
6138 # define SD_INIT_NAME(sd, type) do { } while (0)
6141 #define SD_INIT_FUNC(type) \
6142 static noinline struct sched_domain * \
6143 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
6145 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
6146 *sd = SD_##type##_INIT; \
6147 SD_INIT_NAME(sd, type); \
6148 sd->private = &tl->data; \
6153 #ifdef CONFIG_SCHED_SMT
6154 SD_INIT_FUNC(SIBLING)
6156 #ifdef CONFIG_SCHED_MC
6159 #ifdef CONFIG_SCHED_BOOK
6163 static int default_relax_domain_level = -1;
6164 int sched_domain_level_max;
6166 static int __init setup_relax_domain_level(char *str)
6170 val = simple_strtoul(str, NULL, 0);
6171 if (val < sched_domain_level_max)
6172 default_relax_domain_level = val;
6176 __setup("relax_domain_level=", setup_relax_domain_level);
6178 static void set_domain_attribute(struct sched_domain *sd,
6179 struct sched_domain_attr *attr)
6183 if (!attr || attr->relax_domain_level < 0) {
6184 if (default_relax_domain_level < 0)
6187 request = default_relax_domain_level;
6189 request = attr->relax_domain_level;
6190 if (request < sd->level) {
6191 /* turn off idle balance on this domain */
6192 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6194 /* turn on idle balance on this domain */
6195 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6199 static void __sdt_free(const struct cpumask *cpu_map);
6200 static int __sdt_alloc(const struct cpumask *cpu_map);
6202 static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
6203 const struct cpumask *cpu_map)
6207 if (!atomic_read(&d->rd->refcount))
6208 free_rootdomain(&d->rd->rcu); /* fall through */
6210 free_percpu(d->sd); /* fall through */
6212 __sdt_free(cpu_map); /* fall through */
6218 static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
6219 const struct cpumask *cpu_map)
6221 memset(d, 0, sizeof(*d));
6223 if (__sdt_alloc(cpu_map))
6224 return sa_sd_storage;
6225 d->sd = alloc_percpu(struct sched_domain *);
6227 return sa_sd_storage;
6228 d->rd = alloc_rootdomain();
6231 return sa_rootdomain;
6235 * NULL the sd_data elements we've used to build the sched_domain and
6236 * sched_group structure so that the subsequent __free_domain_allocs()
6237 * will not free the data we're using.
6239 static void claim_allocations(int cpu, struct sched_domain *sd)
6241 struct sd_data *sdd = sd->private;
6243 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
6244 *per_cpu_ptr(sdd->sd, cpu) = NULL;
6246 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
6247 *per_cpu_ptr(sdd->sg, cpu) = NULL;
6249 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref))
6250 *per_cpu_ptr(sdd->sgp, cpu) = NULL;
6253 #ifdef CONFIG_SCHED_SMT
6254 static const struct cpumask *cpu_smt_mask(int cpu)
6256 return topology_thread_cpumask(cpu);
6261 * Topology list, bottom-up.
6263 static struct sched_domain_topology_level default_topology[] = {
6264 #ifdef CONFIG_SCHED_SMT
6265 { sd_init_SIBLING, cpu_smt_mask, },
6267 #ifdef CONFIG_SCHED_MC
6268 { sd_init_MC, cpu_coregroup_mask, },
6270 #ifdef CONFIG_SCHED_BOOK
6271 { sd_init_BOOK, cpu_book_mask, },
6273 { sd_init_CPU, cpu_cpu_mask, },
6277 static struct sched_domain_topology_level *sched_domain_topology = default_topology;
6281 static int sched_domains_numa_levels;
6282 static int sched_domains_numa_scale;
6283 static int *sched_domains_numa_distance;
6284 static struct cpumask ***sched_domains_numa_masks;
6285 static int sched_domains_curr_level;
6287 static inline int sd_local_flags(int level)
6289 if (sched_domains_numa_distance[level] > REMOTE_DISTANCE)
6292 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE;
6295 static struct sched_domain *
6296 sd_numa_init(struct sched_domain_topology_level *tl, int cpu)
6298 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
6299 int level = tl->numa_level;
6300 int sd_weight = cpumask_weight(
6301 sched_domains_numa_masks[level][cpu_to_node(cpu)]);
6303 *sd = (struct sched_domain){
6304 .min_interval = sd_weight,
6305 .max_interval = 2*sd_weight,
6307 .imbalance_pct = 125,
6308 .cache_nice_tries = 2,
6315 .flags = 1*SD_LOAD_BALANCE
6316 | 1*SD_BALANCE_NEWIDLE
6322 | 0*SD_SHARE_CPUPOWER
6323 | 0*SD_SHARE_PKG_RESOURCES
6325 | 0*SD_PREFER_SIBLING
6326 | sd_local_flags(level)
6328 .last_balance = jiffies,
6329 .balance_interval = sd_weight,
6331 SD_INIT_NAME(sd, NUMA);
6332 sd->private = &tl->data;
6335 * Ugly hack to pass state to sd_numa_mask()...
6337 sched_domains_curr_level = tl->numa_level;
6342 static const struct cpumask *sd_numa_mask(int cpu)
6344 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
6347 static void sched_init_numa(void)
6349 int next_distance, curr_distance = node_distance(0, 0);
6350 struct sched_domain_topology_level *tl;
6354 sched_domains_numa_scale = curr_distance;
6355 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL);
6356 if (!sched_domains_numa_distance)
6360 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6361 * unique distances in the node_distance() table.
6363 * Assumes node_distance(0,j) includes all distances in
6364 * node_distance(i,j) in order to avoid cubic time.
6366 * XXX: could be optimized to O(n log n) by using sort()
6368 next_distance = curr_distance;
6369 for (i = 0; i < nr_node_ids; i++) {
6370 for (j = 0; j < nr_node_ids; j++) {
6371 int distance = node_distance(0, j);
6372 if (distance > curr_distance &&
6373 (distance < next_distance ||
6374 next_distance == curr_distance))
6375 next_distance = distance;
6377 if (next_distance != curr_distance) {
6378 sched_domains_numa_distance[level++] = next_distance;
6379 sched_domains_numa_levels = level;
6380 curr_distance = next_distance;
6384 * 'level' contains the number of unique distances, excluding the
6385 * identity distance node_distance(i,i).
6387 * The sched_domains_nume_distance[] array includes the actual distance
6391 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
6392 if (!sched_domains_numa_masks)
6396 * Now for each level, construct a mask per node which contains all
6397 * cpus of nodes that are that many hops away from us.
6399 for (i = 0; i < level; i++) {
6400 sched_domains_numa_masks[i] =
6401 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
6402 if (!sched_domains_numa_masks[i])
6405 for (j = 0; j < nr_node_ids; j++) {
6406 struct cpumask *mask = kzalloc_node(cpumask_size(), GFP_KERNEL, j);
6410 sched_domains_numa_masks[i][j] = mask;
6412 for (k = 0; k < nr_node_ids; k++) {
6413 if (node_distance(j, k) > sched_domains_numa_distance[i])
6416 cpumask_or(mask, mask, cpumask_of_node(k));
6421 tl = kzalloc((ARRAY_SIZE(default_topology) + level) *
6422 sizeof(struct sched_domain_topology_level), GFP_KERNEL);
6427 * Copy the default topology bits..
6429 for (i = 0; default_topology[i].init; i++)
6430 tl[i] = default_topology[i];
6433 * .. and append 'j' levels of NUMA goodness.
6435 for (j = 0; j < level; i++, j++) {
6436 tl[i] = (struct sched_domain_topology_level){
6437 .init = sd_numa_init,
6438 .mask = sd_numa_mask,
6439 .flags = SDTL_OVERLAP,
6444 sched_domain_topology = tl;
6447 static inline void sched_init_numa(void)
6450 #endif /* CONFIG_NUMA */
6452 static int __sdt_alloc(const struct cpumask *cpu_map)
6454 struct sched_domain_topology_level *tl;
6457 for (tl = sched_domain_topology; tl->init; tl++) {
6458 struct sd_data *sdd = &tl->data;
6460 sdd->sd = alloc_percpu(struct sched_domain *);
6464 sdd->sg = alloc_percpu(struct sched_group *);
6468 sdd->sgp = alloc_percpu(struct sched_group_power *);
6472 for_each_cpu(j, cpu_map) {
6473 struct sched_domain *sd;
6474 struct sched_group *sg;
6475 struct sched_group_power *sgp;
6477 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
6478 GFP_KERNEL, cpu_to_node(j));
6482 *per_cpu_ptr(sdd->sd, j) = sd;
6484 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
6485 GFP_KERNEL, cpu_to_node(j));
6491 *per_cpu_ptr(sdd->sg, j) = sg;
6493 sgp = kzalloc_node(sizeof(struct sched_group_power),
6494 GFP_KERNEL, cpu_to_node(j));
6498 *per_cpu_ptr(sdd->sgp, j) = sgp;
6505 static void __sdt_free(const struct cpumask *cpu_map)
6507 struct sched_domain_topology_level *tl;
6510 for (tl = sched_domain_topology; tl->init; tl++) {
6511 struct sd_data *sdd = &tl->data;
6513 for_each_cpu(j, cpu_map) {
6514 struct sched_domain *sd;
6517 sd = *per_cpu_ptr(sdd->sd, j);
6518 if (sd && (sd->flags & SD_OVERLAP))
6519 free_sched_groups(sd->groups, 0);
6520 kfree(*per_cpu_ptr(sdd->sd, j));
6524 kfree(*per_cpu_ptr(sdd->sg, j));
6526 kfree(*per_cpu_ptr(sdd->sgp, j));
6528 free_percpu(sdd->sd);
6530 free_percpu(sdd->sg);
6532 free_percpu(sdd->sgp);
6537 struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
6538 struct s_data *d, const struct cpumask *cpu_map,
6539 struct sched_domain_attr *attr, struct sched_domain *child,
6542 struct sched_domain *sd = tl->init(tl, cpu);
6546 set_domain_attribute(sd, attr);
6547 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
6549 sd->level = child->level + 1;
6550 sched_domain_level_max = max(sched_domain_level_max, sd->level);
6559 * Build sched domains for a given set of cpus and attach the sched domains
6560 * to the individual cpus
6562 static int build_sched_domains(const struct cpumask *cpu_map,
6563 struct sched_domain_attr *attr)
6565 enum s_alloc alloc_state = sa_none;
6566 struct sched_domain *sd;
6568 int i, ret = -ENOMEM;
6570 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
6571 if (alloc_state != sa_rootdomain)
6574 /* Set up domains for cpus specified by the cpu_map. */
6575 for_each_cpu(i, cpu_map) {
6576 struct sched_domain_topology_level *tl;
6579 for (tl = sched_domain_topology; tl->init; tl++) {
6580 sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);
6581 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
6582 sd->flags |= SD_OVERLAP;
6583 if (cpumask_equal(cpu_map, sched_domain_span(sd)))
6590 *per_cpu_ptr(d.sd, i) = sd;
6593 /* Build the groups for the domains */
6594 for_each_cpu(i, cpu_map) {
6595 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6596 sd->span_weight = cpumask_weight(sched_domain_span(sd));
6597 if (sd->flags & SD_OVERLAP) {
6598 if (build_overlap_sched_groups(sd, i))
6601 if (build_sched_groups(sd, i))
6607 /* Calculate CPU power for physical packages and nodes */
6608 for (i = nr_cpumask_bits-1; i >= 0; i--) {
6609 if (!cpumask_test_cpu(i, cpu_map))
6612 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6613 claim_allocations(i, sd);
6614 init_sched_groups_power(i, sd);
6618 /* Attach the domains */
6620 for_each_cpu(i, cpu_map) {
6621 sd = *per_cpu_ptr(d.sd, i);
6622 cpu_attach_domain(sd, d.rd, i);
6628 __free_domain_allocs(&d, alloc_state, cpu_map);
6632 static cpumask_var_t *doms_cur; /* current sched domains */
6633 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
6634 static struct sched_domain_attr *dattr_cur;
6635 /* attribues of custom domains in 'doms_cur' */
6638 * Special case: If a kmalloc of a doms_cur partition (array of
6639 * cpumask) fails, then fallback to a single sched domain,
6640 * as determined by the single cpumask fallback_doms.
6642 static cpumask_var_t fallback_doms;
6645 * arch_update_cpu_topology lets virtualized architectures update the
6646 * cpu core maps. It is supposed to return 1 if the topology changed
6647 * or 0 if it stayed the same.
6649 int __attribute__((weak)) arch_update_cpu_topology(void)
6654 cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
6657 cpumask_var_t *doms;
6659 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
6662 for (i = 0; i < ndoms; i++) {
6663 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
6664 free_sched_domains(doms, i);
6671 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
6674 for (i = 0; i < ndoms; i++)
6675 free_cpumask_var(doms[i]);
6680 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6681 * For now this just excludes isolated cpus, but could be used to
6682 * exclude other special cases in the future.
6684 static int init_sched_domains(const struct cpumask *cpu_map)
6688 arch_update_cpu_topology();
6690 doms_cur = alloc_sched_domains(ndoms_cur);
6692 doms_cur = &fallback_doms;
6693 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
6695 err = build_sched_domains(doms_cur[0], NULL);
6696 register_sched_domain_sysctl();
6702 * Detach sched domains from a group of cpus specified in cpu_map
6703 * These cpus will now be attached to the NULL domain
6705 static void detach_destroy_domains(const struct cpumask *cpu_map)
6710 for_each_cpu(i, cpu_map)
6711 cpu_attach_domain(NULL, &def_root_domain, i);
6715 /* handle null as "default" */
6716 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
6717 struct sched_domain_attr *new, int idx_new)
6719 struct sched_domain_attr tmp;
6726 return !memcmp(cur ? (cur + idx_cur) : &tmp,
6727 new ? (new + idx_new) : &tmp,
6728 sizeof(struct sched_domain_attr));
6732 * Partition sched domains as specified by the 'ndoms_new'
6733 * cpumasks in the array doms_new[] of cpumasks. This compares
6734 * doms_new[] to the current sched domain partitioning, doms_cur[].
6735 * It destroys each deleted domain and builds each new domain.
6737 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6738 * The masks don't intersect (don't overlap.) We should setup one
6739 * sched domain for each mask. CPUs not in any of the cpumasks will
6740 * not be load balanced. If the same cpumask appears both in the
6741 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6744 * The passed in 'doms_new' should be allocated using
6745 * alloc_sched_domains. This routine takes ownership of it and will
6746 * free_sched_domains it when done with it. If the caller failed the
6747 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6748 * and partition_sched_domains() will fallback to the single partition
6749 * 'fallback_doms', it also forces the domains to be rebuilt.
6751 * If doms_new == NULL it will be replaced with cpu_online_mask.
6752 * ndoms_new == 0 is a special case for destroying existing domains,
6753 * and it will not create the default domain.
6755 * Call with hotplug lock held
6757 void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
6758 struct sched_domain_attr *dattr_new)
6763 mutex_lock(&sched_domains_mutex);
6765 /* always unregister in case we don't destroy any domains */
6766 unregister_sched_domain_sysctl();
6768 /* Let architecture update cpu core mappings. */
6769 new_topology = arch_update_cpu_topology();
6771 n = doms_new ? ndoms_new : 0;
6773 /* Destroy deleted domains */
6774 for (i = 0; i < ndoms_cur; i++) {
6775 for (j = 0; j < n && !new_topology; j++) {
6776 if (cpumask_equal(doms_cur[i], doms_new[j])
6777 && dattrs_equal(dattr_cur, i, dattr_new, j))
6780 /* no match - a current sched domain not in new doms_new[] */
6781 detach_destroy_domains(doms_cur[i]);
6786 if (doms_new == NULL) {
6788 doms_new = &fallback_doms;
6789 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
6790 WARN_ON_ONCE(dattr_new);
6793 /* Build new domains */
6794 for (i = 0; i < ndoms_new; i++) {
6795 for (j = 0; j < ndoms_cur && !new_topology; j++) {
6796 if (cpumask_equal(doms_new[i], doms_cur[j])
6797 && dattrs_equal(dattr_new, i, dattr_cur, j))
6800 /* no match - add a new doms_new */
6801 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
6806 /* Remember the new sched domains */
6807 if (doms_cur != &fallback_doms)
6808 free_sched_domains(doms_cur, ndoms_cur);
6809 kfree(dattr_cur); /* kfree(NULL) is safe */
6810 doms_cur = doms_new;
6811 dattr_cur = dattr_new;
6812 ndoms_cur = ndoms_new;
6814 register_sched_domain_sysctl();
6816 mutex_unlock(&sched_domains_mutex);
6820 * Update cpusets according to cpu_active mask. If cpusets are
6821 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6822 * around partition_sched_domains().
6824 static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
6827 switch (action & ~CPU_TASKS_FROZEN) {
6829 case CPU_DOWN_FAILED:
6830 cpuset_update_active_cpus();
6837 static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
6840 switch (action & ~CPU_TASKS_FROZEN) {
6841 case CPU_DOWN_PREPARE:
6842 cpuset_update_active_cpus();
6849 void __init sched_init_smp(void)
6851 cpumask_var_t non_isolated_cpus;
6853 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
6854 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
6859 mutex_lock(&sched_domains_mutex);
6860 init_sched_domains(cpu_active_mask);
6861 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
6862 if (cpumask_empty(non_isolated_cpus))
6863 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
6864 mutex_unlock(&sched_domains_mutex);
6867 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
6868 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
6870 /* RT runtime code needs to handle some hotplug events */
6871 hotcpu_notifier(update_runtime, 0);
6875 /* Move init over to a non-isolated CPU */
6876 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
6878 sched_init_granularity();
6879 free_cpumask_var(non_isolated_cpus);
6881 init_sched_rt_class();
6884 void __init sched_init_smp(void)
6886 sched_init_granularity();
6888 #endif /* CONFIG_SMP */
6890 const_debug unsigned int sysctl_timer_migration = 1;
6892 int in_sched_functions(unsigned long addr)
6894 return in_lock_functions(addr) ||
6895 (addr >= (unsigned long)__sched_text_start
6896 && addr < (unsigned long)__sched_text_end);
6899 #ifdef CONFIG_CGROUP_SCHED
6900 struct task_group root_task_group;
6903 DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
6905 void __init sched_init(void)
6908 unsigned long alloc_size = 0, ptr;
6910 #ifdef CONFIG_FAIR_GROUP_SCHED
6911 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
6913 #ifdef CONFIG_RT_GROUP_SCHED
6914 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
6916 #ifdef CONFIG_CPUMASK_OFFSTACK
6917 alloc_size += num_possible_cpus() * cpumask_size();
6920 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
6922 #ifdef CONFIG_FAIR_GROUP_SCHED
6923 root_task_group.se = (struct sched_entity **)ptr;
6924 ptr += nr_cpu_ids * sizeof(void **);
6926 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
6927 ptr += nr_cpu_ids * sizeof(void **);
6929 #endif /* CONFIG_FAIR_GROUP_SCHED */
6930 #ifdef CONFIG_RT_GROUP_SCHED
6931 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
6932 ptr += nr_cpu_ids * sizeof(void **);
6934 root_task_group.rt_rq = (struct rt_rq **)ptr;
6935 ptr += nr_cpu_ids * sizeof(void **);
6937 #endif /* CONFIG_RT_GROUP_SCHED */
6938 #ifdef CONFIG_CPUMASK_OFFSTACK
6939 for_each_possible_cpu(i) {
6940 per_cpu(load_balance_tmpmask, i) = (void *)ptr;
6941 ptr += cpumask_size();
6943 #endif /* CONFIG_CPUMASK_OFFSTACK */
6947 init_defrootdomain();
6950 init_rt_bandwidth(&def_rt_bandwidth,
6951 global_rt_period(), global_rt_runtime());
6953 #ifdef CONFIG_RT_GROUP_SCHED
6954 init_rt_bandwidth(&root_task_group.rt_bandwidth,
6955 global_rt_period(), global_rt_runtime());
6956 #endif /* CONFIG_RT_GROUP_SCHED */
6958 #ifdef CONFIG_CGROUP_SCHED
6959 list_add(&root_task_group.list, &task_groups);
6960 INIT_LIST_HEAD(&root_task_group.children);
6961 INIT_LIST_HEAD(&root_task_group.siblings);
6962 autogroup_init(&init_task);
6964 #endif /* CONFIG_CGROUP_SCHED */
6966 #ifdef CONFIG_CGROUP_CPUACCT
6967 root_cpuacct.cpustat = &kernel_cpustat;
6968 root_cpuacct.cpuusage = alloc_percpu(u64);
6969 /* Too early, not expected to fail */
6970 BUG_ON(!root_cpuacct.cpuusage);
6972 for_each_possible_cpu(i) {
6976 raw_spin_lock_init(&rq->lock);
6978 rq->calc_load_active = 0;
6979 rq->calc_load_update = jiffies + LOAD_FREQ;
6980 init_cfs_rq(&rq->cfs);
6981 init_rt_rq(&rq->rt, rq);
6982 #ifdef CONFIG_FAIR_GROUP_SCHED
6983 root_task_group.shares = ROOT_TASK_GROUP_LOAD;
6984 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
6986 * How much cpu bandwidth does root_task_group get?
6988 * In case of task-groups formed thr' the cgroup filesystem, it
6989 * gets 100% of the cpu resources in the system. This overall
6990 * system cpu resource is divided among the tasks of
6991 * root_task_group and its child task-groups in a fair manner,
6992 * based on each entity's (task or task-group's) weight
6993 * (se->load.weight).
6995 * In other words, if root_task_group has 10 tasks of weight
6996 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6997 * then A0's share of the cpu resource is:
6999 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7001 * We achieve this by letting root_task_group's tasks sit
7002 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7004 init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
7005 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
7006 #endif /* CONFIG_FAIR_GROUP_SCHED */
7008 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
7009 #ifdef CONFIG_RT_GROUP_SCHED
7010 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
7011 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
7014 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
7015 rq->cpu_load[j] = 0;
7017 rq->last_load_update_tick = jiffies;
7022 rq->cpu_power = SCHED_POWER_SCALE;
7023 rq->post_schedule = 0;
7024 rq->active_balance = 0;
7025 rq->next_balance = jiffies;
7030 rq->avg_idle = 2*sysctl_sched_migration_cost;
7032 INIT_LIST_HEAD(&rq->cfs_tasks);
7034 rq_attach_root(rq, &def_root_domain);
7040 atomic_set(&rq->nr_iowait, 0);
7043 set_load_weight(&init_task);
7045 #ifdef CONFIG_PREEMPT_NOTIFIERS
7046 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
7049 #ifdef CONFIG_RT_MUTEXES
7050 plist_head_init(&init_task.pi_waiters);
7054 * The boot idle thread does lazy MMU switching as well:
7056 atomic_inc(&init_mm.mm_count);
7057 enter_lazy_tlb(&init_mm, current);
7060 * Make us the idle thread. Technically, schedule() should not be
7061 * called from this thread, however somewhere below it might be,
7062 * but because we are the idle thread, we just pick up running again
7063 * when this runqueue becomes "idle".
7065 init_idle(current, smp_processor_id());
7067 calc_load_update = jiffies + LOAD_FREQ;
7070 * During early bootup we pretend to be a normal task:
7072 current->sched_class = &fair_sched_class;
7075 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
7076 /* May be allocated at isolcpus cmdline parse time */
7077 if (cpu_isolated_map == NULL)
7078 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
7079 idle_thread_set_boot_cpu();
7081 init_sched_fair_class();
7083 scheduler_running = 1;
7086 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7087 static inline int preempt_count_equals(int preempt_offset)
7089 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
7091 return (nested == preempt_offset);
7094 void __might_sleep(const char *file, int line, int preempt_offset)
7096 static unsigned long prev_jiffy; /* ratelimiting */
7098 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7099 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
7100 system_state != SYSTEM_RUNNING || oops_in_progress)
7102 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
7104 prev_jiffy = jiffies;
7107 "BUG: sleeping function called from invalid context at %s:%d\n",
7110 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7111 in_atomic(), irqs_disabled(),
7112 current->pid, current->comm);
7114 debug_show_held_locks(current);
7115 if (irqs_disabled())
7116 print_irqtrace_events(current);
7119 EXPORT_SYMBOL(__might_sleep);
7122 #ifdef CONFIG_MAGIC_SYSRQ
7123 static void normalize_task(struct rq *rq, struct task_struct *p)
7125 const struct sched_class *prev_class = p->sched_class;
7126 int old_prio = p->prio;
7131 dequeue_task(rq, p, 0);
7132 __setscheduler(rq, p, SCHED_NORMAL, 0);
7134 enqueue_task(rq, p, 0);
7135 resched_task(rq->curr);
7138 check_class_changed(rq, p, prev_class, old_prio);
7141 void normalize_rt_tasks(void)
7143 struct task_struct *g, *p;
7144 unsigned long flags;
7147 read_lock_irqsave(&tasklist_lock, flags);
7148 do_each_thread(g, p) {
7150 * Only normalize user tasks:
7155 p->se.exec_start = 0;
7156 #ifdef CONFIG_SCHEDSTATS
7157 p->se.statistics.wait_start = 0;
7158 p->se.statistics.sleep_start = 0;
7159 p->se.statistics.block_start = 0;
7164 * Renice negative nice level userspace
7167 if (TASK_NICE(p) < 0 && p->mm)
7168 set_user_nice(p, 0);
7172 raw_spin_lock(&p->pi_lock);
7173 rq = __task_rq_lock(p);
7175 normalize_task(rq, p);
7177 __task_rq_unlock(rq);
7178 raw_spin_unlock(&p->pi_lock);
7179 } while_each_thread(g, p);
7181 read_unlock_irqrestore(&tasklist_lock, flags);
7184 #endif /* CONFIG_MAGIC_SYSRQ */
7186 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7188 * These functions are only useful for the IA64 MCA handling, or kdb.
7190 * They can only be called when the whole system has been
7191 * stopped - every CPU needs to be quiescent, and no scheduling
7192 * activity can take place. Using them for anything else would
7193 * be a serious bug, and as a result, they aren't even visible
7194 * under any other configuration.
7198 * curr_task - return the current task for a given cpu.
7199 * @cpu: the processor in question.
7201 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7203 struct task_struct *curr_task(int cpu)
7205 return cpu_curr(cpu);
7208 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7212 * set_curr_task - set the current task for a given cpu.
7213 * @cpu: the processor in question.
7214 * @p: the task pointer to set.
7216 * Description: This function must only be used when non-maskable interrupts
7217 * are serviced on a separate stack. It allows the architecture to switch the
7218 * notion of the current task on a cpu in a non-blocking manner. This function
7219 * must be called with all CPU's synchronized, and interrupts disabled, the
7220 * and caller must save the original value of the current task (see
7221 * curr_task() above) and restore that value before reenabling interrupts and
7222 * re-starting the system.
7224 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7226 void set_curr_task(int cpu, struct task_struct *p)
7233 #ifdef CONFIG_CGROUP_SCHED
7234 /* task_group_lock serializes the addition/removal of task groups */
7235 static DEFINE_SPINLOCK(task_group_lock);
7237 static void free_sched_group(struct task_group *tg)
7239 free_fair_sched_group(tg);
7240 free_rt_sched_group(tg);
7245 /* allocate runqueue etc for a new task group */
7246 struct task_group *sched_create_group(struct task_group *parent)
7248 struct task_group *tg;
7249 unsigned long flags;
7251 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
7253 return ERR_PTR(-ENOMEM);
7255 if (!alloc_fair_sched_group(tg, parent))
7258 if (!alloc_rt_sched_group(tg, parent))
7261 spin_lock_irqsave(&task_group_lock, flags);
7262 list_add_rcu(&tg->list, &task_groups);
7264 WARN_ON(!parent); /* root should already exist */
7266 tg->parent = parent;
7267 INIT_LIST_HEAD(&tg->children);
7268 list_add_rcu(&tg->siblings, &parent->children);
7269 spin_unlock_irqrestore(&task_group_lock, flags);
7274 free_sched_group(tg);
7275 return ERR_PTR(-ENOMEM);
7278 /* rcu callback to free various structures associated with a task group */
7279 static void free_sched_group_rcu(struct rcu_head *rhp)
7281 /* now it should be safe to free those cfs_rqs */
7282 free_sched_group(container_of(rhp, struct task_group, rcu));
7285 /* Destroy runqueue etc associated with a task group */
7286 void sched_destroy_group(struct task_group *tg)
7288 unsigned long flags;
7291 /* end participation in shares distribution */
7292 for_each_possible_cpu(i)
7293 unregister_fair_sched_group(tg, i);
7295 spin_lock_irqsave(&task_group_lock, flags);
7296 list_del_rcu(&tg->list);
7297 list_del_rcu(&tg->siblings);
7298 spin_unlock_irqrestore(&task_group_lock, flags);
7300 /* wait for possible concurrent references to cfs_rqs complete */
7301 call_rcu(&tg->rcu, free_sched_group_rcu);
7304 /* change task's runqueue when it moves between groups.
7305 * The caller of this function should have put the task in its new group
7306 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7307 * reflect its new group.
7309 void sched_move_task(struct task_struct *tsk)
7312 unsigned long flags;
7315 rq = task_rq_lock(tsk, &flags);
7317 running = task_current(rq, tsk);
7321 dequeue_task(rq, tsk, 0);
7322 if (unlikely(running))
7323 tsk->sched_class->put_prev_task(rq, tsk);
7325 #ifdef CONFIG_FAIR_GROUP_SCHED
7326 if (tsk->sched_class->task_move_group)
7327 tsk->sched_class->task_move_group(tsk, on_rq);
7330 set_task_rq(tsk, task_cpu(tsk));
7332 if (unlikely(running))
7333 tsk->sched_class->set_curr_task(rq);
7335 enqueue_task(rq, tsk, 0);
7337 task_rq_unlock(rq, tsk, &flags);
7339 #endif /* CONFIG_CGROUP_SCHED */
7341 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
7342 static unsigned long to_ratio(u64 period, u64 runtime)
7344 if (runtime == RUNTIME_INF)
7347 return div64_u64(runtime << 20, period);
7351 #ifdef CONFIG_RT_GROUP_SCHED
7353 * Ensure that the real time constraints are schedulable.
7355 static DEFINE_MUTEX(rt_constraints_mutex);
7357 /* Must be called with tasklist_lock held */
7358 static inline int tg_has_rt_tasks(struct task_group *tg)
7360 struct task_struct *g, *p;
7362 do_each_thread(g, p) {
7363 if (rt_task(p) && task_rq(p)->rt.tg == tg)
7365 } while_each_thread(g, p);
7370 struct rt_schedulable_data {
7371 struct task_group *tg;
7376 static int tg_rt_schedulable(struct task_group *tg, void *data)
7378 struct rt_schedulable_data *d = data;
7379 struct task_group *child;
7380 unsigned long total, sum = 0;
7381 u64 period, runtime;
7383 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7384 runtime = tg->rt_bandwidth.rt_runtime;
7387 period = d->rt_period;
7388 runtime = d->rt_runtime;
7392 * Cannot have more runtime than the period.
7394 if (runtime > period && runtime != RUNTIME_INF)
7398 * Ensure we don't starve existing RT tasks.
7400 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
7403 total = to_ratio(period, runtime);
7406 * Nobody can have more than the global setting allows.
7408 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
7412 * The sum of our children's runtime should not exceed our own.
7414 list_for_each_entry_rcu(child, &tg->children, siblings) {
7415 period = ktime_to_ns(child->rt_bandwidth.rt_period);
7416 runtime = child->rt_bandwidth.rt_runtime;
7418 if (child == d->tg) {
7419 period = d->rt_period;
7420 runtime = d->rt_runtime;
7423 sum += to_ratio(period, runtime);
7432 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
7436 struct rt_schedulable_data data = {
7438 .rt_period = period,
7439 .rt_runtime = runtime,
7443 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
7449 static int tg_set_rt_bandwidth(struct task_group *tg,
7450 u64 rt_period, u64 rt_runtime)
7454 mutex_lock(&rt_constraints_mutex);
7455 read_lock(&tasklist_lock);
7456 err = __rt_schedulable(tg, rt_period, rt_runtime);
7460 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7461 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
7462 tg->rt_bandwidth.rt_runtime = rt_runtime;
7464 for_each_possible_cpu(i) {
7465 struct rt_rq *rt_rq = tg->rt_rq[i];
7467 raw_spin_lock(&rt_rq->rt_runtime_lock);
7468 rt_rq->rt_runtime = rt_runtime;
7469 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7471 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7473 read_unlock(&tasklist_lock);
7474 mutex_unlock(&rt_constraints_mutex);
7479 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
7481 u64 rt_runtime, rt_period;
7483 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7484 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
7485 if (rt_runtime_us < 0)
7486 rt_runtime = RUNTIME_INF;
7488 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7491 long sched_group_rt_runtime(struct task_group *tg)
7495 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
7498 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
7499 do_div(rt_runtime_us, NSEC_PER_USEC);
7500 return rt_runtime_us;
7503 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
7505 u64 rt_runtime, rt_period;
7507 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
7508 rt_runtime = tg->rt_bandwidth.rt_runtime;
7513 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7516 long sched_group_rt_period(struct task_group *tg)
7520 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
7521 do_div(rt_period_us, NSEC_PER_USEC);
7522 return rt_period_us;
7525 static int sched_rt_global_constraints(void)
7527 u64 runtime, period;
7530 if (sysctl_sched_rt_period <= 0)
7533 runtime = global_rt_runtime();
7534 period = global_rt_period();
7537 * Sanity check on the sysctl variables.
7539 if (runtime > period && runtime != RUNTIME_INF)
7542 mutex_lock(&rt_constraints_mutex);
7543 read_lock(&tasklist_lock);
7544 ret = __rt_schedulable(NULL, 0, 0);
7545 read_unlock(&tasklist_lock);
7546 mutex_unlock(&rt_constraints_mutex);
7551 int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
7553 /* Don't accept realtime tasks when there is no way for them to run */
7554 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
7560 #else /* !CONFIG_RT_GROUP_SCHED */
7561 static int sched_rt_global_constraints(void)
7563 unsigned long flags;
7566 if (sysctl_sched_rt_period <= 0)
7570 * There's always some RT tasks in the root group
7571 * -- migration, kstopmachine etc..
7573 if (sysctl_sched_rt_runtime == 0)
7576 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
7577 for_each_possible_cpu(i) {
7578 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
7580 raw_spin_lock(&rt_rq->rt_runtime_lock);
7581 rt_rq->rt_runtime = global_rt_runtime();
7582 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7584 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
7588 #endif /* CONFIG_RT_GROUP_SCHED */
7590 int sched_rt_handler(struct ctl_table *table, int write,
7591 void __user *buffer, size_t *lenp,
7595 int old_period, old_runtime;
7596 static DEFINE_MUTEX(mutex);
7599 old_period = sysctl_sched_rt_period;
7600 old_runtime = sysctl_sched_rt_runtime;
7602 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7604 if (!ret && write) {
7605 ret = sched_rt_global_constraints();
7607 sysctl_sched_rt_period = old_period;
7608 sysctl_sched_rt_runtime = old_runtime;
7610 def_rt_bandwidth.rt_runtime = global_rt_runtime();
7611 def_rt_bandwidth.rt_period =
7612 ns_to_ktime(global_rt_period());
7615 mutex_unlock(&mutex);
7620 #ifdef CONFIG_CGROUP_SCHED
7622 /* return corresponding task_group object of a cgroup */
7623 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
7625 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
7626 struct task_group, css);
7629 static struct cgroup_subsys_state *cpu_cgroup_create(struct cgroup *cgrp)
7631 struct task_group *tg, *parent;
7633 if (!cgrp->parent) {
7634 /* This is early initialization for the top cgroup */
7635 return &root_task_group.css;
7638 parent = cgroup_tg(cgrp->parent);
7639 tg = sched_create_group(parent);
7641 return ERR_PTR(-ENOMEM);
7646 static void cpu_cgroup_destroy(struct cgroup *cgrp)
7648 struct task_group *tg = cgroup_tg(cgrp);
7650 sched_destroy_group(tg);
7653 static int cpu_cgroup_can_attach(struct cgroup *cgrp,
7654 struct cgroup_taskset *tset)
7656 struct task_struct *task;
7658 cgroup_taskset_for_each(task, cgrp, tset) {
7659 #ifdef CONFIG_RT_GROUP_SCHED
7660 if (!sched_rt_can_attach(cgroup_tg(cgrp), task))
7663 /* We don't support RT-tasks being in separate groups */
7664 if (task->sched_class != &fair_sched_class)
7671 static void cpu_cgroup_attach(struct cgroup *cgrp,
7672 struct cgroup_taskset *tset)
7674 struct task_struct *task;
7676 cgroup_taskset_for_each(task, cgrp, tset)
7677 sched_move_task(task);
7681 cpu_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp,
7682 struct task_struct *task)
7685 * cgroup_exit() is called in the copy_process() failure path.
7686 * Ignore this case since the task hasn't ran yet, this avoids
7687 * trying to poke a half freed task state from generic code.
7689 if (!(task->flags & PF_EXITING))
7692 sched_move_task(task);
7695 #ifdef CONFIG_FAIR_GROUP_SCHED
7696 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
7699 return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval));
7702 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
7704 struct task_group *tg = cgroup_tg(cgrp);
7706 return (u64) scale_load_down(tg->shares);
7709 #ifdef CONFIG_CFS_BANDWIDTH
7710 static DEFINE_MUTEX(cfs_constraints_mutex);
7712 const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
7713 const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
7715 static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
7717 static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
7719 int i, ret = 0, runtime_enabled, runtime_was_enabled;
7720 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7722 if (tg == &root_task_group)
7726 * Ensure we have at some amount of bandwidth every period. This is
7727 * to prevent reaching a state of large arrears when throttled via
7728 * entity_tick() resulting in prolonged exit starvation.
7730 if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
7734 * Likewise, bound things on the otherside by preventing insane quota
7735 * periods. This also allows us to normalize in computing quota
7738 if (period > max_cfs_quota_period)
7741 mutex_lock(&cfs_constraints_mutex);
7742 ret = __cfs_schedulable(tg, period, quota);
7746 runtime_enabled = quota != RUNTIME_INF;
7747 runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
7748 account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled);
7749 raw_spin_lock_irq(&cfs_b->lock);
7750 cfs_b->period = ns_to_ktime(period);
7751 cfs_b->quota = quota;
7753 __refill_cfs_bandwidth_runtime(cfs_b);
7754 /* restart the period timer (if active) to handle new period expiry */
7755 if (runtime_enabled && cfs_b->timer_active) {
7756 /* force a reprogram */
7757 cfs_b->timer_active = 0;
7758 __start_cfs_bandwidth(cfs_b);
7760 raw_spin_unlock_irq(&cfs_b->lock);
7762 for_each_possible_cpu(i) {
7763 struct cfs_rq *cfs_rq = tg->cfs_rq[i];
7764 struct rq *rq = cfs_rq->rq;
7766 raw_spin_lock_irq(&rq->lock);
7767 cfs_rq->runtime_enabled = runtime_enabled;
7768 cfs_rq->runtime_remaining = 0;
7770 if (cfs_rq->throttled)
7771 unthrottle_cfs_rq(cfs_rq);
7772 raw_spin_unlock_irq(&rq->lock);
7775 mutex_unlock(&cfs_constraints_mutex);
7780 int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
7784 period = ktime_to_ns(tg->cfs_bandwidth.period);
7785 if (cfs_quota_us < 0)
7786 quota = RUNTIME_INF;
7788 quota = (u64)cfs_quota_us * NSEC_PER_USEC;
7790 return tg_set_cfs_bandwidth(tg, period, quota);
7793 long tg_get_cfs_quota(struct task_group *tg)
7797 if (tg->cfs_bandwidth.quota == RUNTIME_INF)
7800 quota_us = tg->cfs_bandwidth.quota;
7801 do_div(quota_us, NSEC_PER_USEC);
7806 int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
7810 period = (u64)cfs_period_us * NSEC_PER_USEC;
7811 quota = tg->cfs_bandwidth.quota;
7813 return tg_set_cfs_bandwidth(tg, period, quota);
7816 long tg_get_cfs_period(struct task_group *tg)
7820 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
7821 do_div(cfs_period_us, NSEC_PER_USEC);
7823 return cfs_period_us;
7826 static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft)
7828 return tg_get_cfs_quota(cgroup_tg(cgrp));
7831 static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype,
7834 return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us);
7837 static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft)
7839 return tg_get_cfs_period(cgroup_tg(cgrp));
7842 static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype,
7845 return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us);
7848 struct cfs_schedulable_data {
7849 struct task_group *tg;
7854 * normalize group quota/period to be quota/max_period
7855 * note: units are usecs
7857 static u64 normalize_cfs_quota(struct task_group *tg,
7858 struct cfs_schedulable_data *d)
7866 period = tg_get_cfs_period(tg);
7867 quota = tg_get_cfs_quota(tg);
7870 /* note: these should typically be equivalent */
7871 if (quota == RUNTIME_INF || quota == -1)
7874 return to_ratio(period, quota);
7877 static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
7879 struct cfs_schedulable_data *d = data;
7880 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7881 s64 quota = 0, parent_quota = -1;
7884 quota = RUNTIME_INF;
7886 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
7888 quota = normalize_cfs_quota(tg, d);
7889 parent_quota = parent_b->hierarchal_quota;
7892 * ensure max(child_quota) <= parent_quota, inherit when no
7895 if (quota == RUNTIME_INF)
7896 quota = parent_quota;
7897 else if (parent_quota != RUNTIME_INF && quota > parent_quota)
7900 cfs_b->hierarchal_quota = quota;
7905 static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
7908 struct cfs_schedulable_data data = {
7914 if (quota != RUNTIME_INF) {
7915 do_div(data.period, NSEC_PER_USEC);
7916 do_div(data.quota, NSEC_PER_USEC);
7920 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
7926 static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft,
7927 struct cgroup_map_cb *cb)
7929 struct task_group *tg = cgroup_tg(cgrp);
7930 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
7932 cb->fill(cb, "nr_periods", cfs_b->nr_periods);
7933 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled);
7934 cb->fill(cb, "throttled_time", cfs_b->throttled_time);
7938 #endif /* CONFIG_CFS_BANDWIDTH */
7939 #endif /* CONFIG_FAIR_GROUP_SCHED */
7941 #ifdef CONFIG_RT_GROUP_SCHED
7942 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
7945 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
7948 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
7950 return sched_group_rt_runtime(cgroup_tg(cgrp));
7953 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
7956 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
7959 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
7961 return sched_group_rt_period(cgroup_tg(cgrp));
7963 #endif /* CONFIG_RT_GROUP_SCHED */
7965 static struct cftype cpu_files[] = {
7966 #ifdef CONFIG_FAIR_GROUP_SCHED
7969 .read_u64 = cpu_shares_read_u64,
7970 .write_u64 = cpu_shares_write_u64,
7973 #ifdef CONFIG_CFS_BANDWIDTH
7975 .name = "cfs_quota_us",
7976 .read_s64 = cpu_cfs_quota_read_s64,
7977 .write_s64 = cpu_cfs_quota_write_s64,
7980 .name = "cfs_period_us",
7981 .read_u64 = cpu_cfs_period_read_u64,
7982 .write_u64 = cpu_cfs_period_write_u64,
7986 .read_map = cpu_stats_show,
7989 #ifdef CONFIG_RT_GROUP_SCHED
7991 .name = "rt_runtime_us",
7992 .read_s64 = cpu_rt_runtime_read,
7993 .write_s64 = cpu_rt_runtime_write,
7996 .name = "rt_period_us",
7997 .read_u64 = cpu_rt_period_read_uint,
7998 .write_u64 = cpu_rt_period_write_uint,
8004 struct cgroup_subsys cpu_cgroup_subsys = {
8006 .create = cpu_cgroup_create,
8007 .destroy = cpu_cgroup_destroy,
8008 .can_attach = cpu_cgroup_can_attach,
8009 .attach = cpu_cgroup_attach,
8010 .exit = cpu_cgroup_exit,
8011 .subsys_id = cpu_cgroup_subsys_id,
8012 .base_cftypes = cpu_files,
8016 #endif /* CONFIG_CGROUP_SCHED */
8018 #ifdef CONFIG_CGROUP_CPUACCT
8021 * CPU accounting code for task groups.
8023 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8024 * (balbir@in.ibm.com).
8027 /* create a new cpu accounting group */
8028 static struct cgroup_subsys_state *cpuacct_create(struct cgroup *cgrp)
8033 return &root_cpuacct.css;
8035 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
8039 ca->cpuusage = alloc_percpu(u64);
8043 ca->cpustat = alloc_percpu(struct kernel_cpustat);
8045 goto out_free_cpuusage;
8050 free_percpu(ca->cpuusage);
8054 return ERR_PTR(-ENOMEM);
8057 /* destroy an existing cpu accounting group */
8058 static void cpuacct_destroy(struct cgroup *cgrp)
8060 struct cpuacct *ca = cgroup_ca(cgrp);
8062 free_percpu(ca->cpustat);
8063 free_percpu(ca->cpuusage);
8067 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
8069 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8072 #ifndef CONFIG_64BIT
8074 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
8076 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8078 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8086 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
8088 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8090 #ifndef CONFIG_64BIT
8092 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8094 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8096 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8102 /* return total cpu usage (in nanoseconds) of a group */
8103 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
8105 struct cpuacct *ca = cgroup_ca(cgrp);
8106 u64 totalcpuusage = 0;
8109 for_each_present_cpu(i)
8110 totalcpuusage += cpuacct_cpuusage_read(ca, i);
8112 return totalcpuusage;
8115 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
8118 struct cpuacct *ca = cgroup_ca(cgrp);
8127 for_each_present_cpu(i)
8128 cpuacct_cpuusage_write(ca, i, 0);
8134 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
8137 struct cpuacct *ca = cgroup_ca(cgroup);
8141 for_each_present_cpu(i) {
8142 percpu = cpuacct_cpuusage_read(ca, i);
8143 seq_printf(m, "%llu ", (unsigned long long) percpu);
8145 seq_printf(m, "\n");
8149 static const char *cpuacct_stat_desc[] = {
8150 [CPUACCT_STAT_USER] = "user",
8151 [CPUACCT_STAT_SYSTEM] = "system",
8154 static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
8155 struct cgroup_map_cb *cb)
8157 struct cpuacct *ca = cgroup_ca(cgrp);
8161 for_each_online_cpu(cpu) {
8162 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
8163 val += kcpustat->cpustat[CPUTIME_USER];
8164 val += kcpustat->cpustat[CPUTIME_NICE];
8166 val = cputime64_to_clock_t(val);
8167 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val);
8170 for_each_online_cpu(cpu) {
8171 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
8172 val += kcpustat->cpustat[CPUTIME_SYSTEM];
8173 val += kcpustat->cpustat[CPUTIME_IRQ];
8174 val += kcpustat->cpustat[CPUTIME_SOFTIRQ];
8177 val = cputime64_to_clock_t(val);
8178 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val);
8183 static struct cftype files[] = {
8186 .read_u64 = cpuusage_read,
8187 .write_u64 = cpuusage_write,
8190 .name = "usage_percpu",
8191 .read_seq_string = cpuacct_percpu_seq_read,
8195 .read_map = cpuacct_stats_show,
8201 * charge this task's execution time to its accounting group.
8203 * called with rq->lock held.
8205 void cpuacct_charge(struct task_struct *tsk, u64 cputime)
8210 if (unlikely(!cpuacct_subsys.active))
8213 cpu = task_cpu(tsk);
8219 for (; ca; ca = parent_ca(ca)) {
8220 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8221 *cpuusage += cputime;
8227 struct cgroup_subsys cpuacct_subsys = {
8229 .create = cpuacct_create,
8230 .destroy = cpuacct_destroy,
8231 .subsys_id = cpuacct_subsys_id,
8232 .base_cftypes = files,
8234 #endif /* CONFIG_CGROUP_CPUACCT */