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 const char * const sched_feat_names[] = {
146 #include "features.h"
151 static int sched_feat_show(struct seq_file *m, void *v)
155 for (i = 0; i < __SCHED_FEAT_NR; i++) {
156 if (!(sysctl_sched_features & (1UL << i)))
158 seq_printf(m, "%s ", sched_feat_names[i]);
165 #ifdef HAVE_JUMP_LABEL
167 #define jump_label_key__true STATIC_KEY_INIT_TRUE
168 #define jump_label_key__false STATIC_KEY_INIT_FALSE
170 #define SCHED_FEAT(name, enabled) \
171 jump_label_key__##enabled ,
173 struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
174 #include "features.h"
179 static void sched_feat_disable(int i)
181 if (static_key_enabled(&sched_feat_keys[i]))
182 static_key_slow_dec(&sched_feat_keys[i]);
185 static void sched_feat_enable(int i)
187 if (!static_key_enabled(&sched_feat_keys[i]))
188 static_key_slow_inc(&sched_feat_keys[i]);
191 static void sched_feat_disable(int i) { };
192 static void sched_feat_enable(int i) { };
193 #endif /* HAVE_JUMP_LABEL */
196 sched_feat_write(struct file *filp, const char __user *ubuf,
197 size_t cnt, loff_t *ppos)
207 if (copy_from_user(&buf, ubuf, cnt))
213 if (strncmp(cmp, "NO_", 3) == 0) {
218 for (i = 0; i < __SCHED_FEAT_NR; i++) {
219 if (strcmp(cmp, sched_feat_names[i]) == 0) {
221 sysctl_sched_features &= ~(1UL << i);
222 sched_feat_disable(i);
224 sysctl_sched_features |= (1UL << i);
225 sched_feat_enable(i);
231 if (i == __SCHED_FEAT_NR)
239 static int sched_feat_open(struct inode *inode, struct file *filp)
241 return single_open(filp, sched_feat_show, NULL);
244 static const struct file_operations sched_feat_fops = {
245 .open = sched_feat_open,
246 .write = sched_feat_write,
249 .release = single_release,
252 static __init int sched_init_debug(void)
254 debugfs_create_file("sched_features", 0644, NULL, NULL,
259 late_initcall(sched_init_debug);
260 #endif /* CONFIG_SCHED_DEBUG */
263 * Number of tasks to iterate in a single balance run.
264 * Limited because this is done with IRQs disabled.
266 const_debug unsigned int sysctl_sched_nr_migrate = 32;
269 * period over which we average the RT time consumption, measured
274 const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
277 * period over which we measure -rt task cpu usage in us.
280 unsigned int sysctl_sched_rt_period = 1000000;
282 __read_mostly int scheduler_running;
285 * part of the period that we allow rt tasks to run in us.
288 int sysctl_sched_rt_runtime = 950000;
293 * __task_rq_lock - lock the rq @p resides on.
295 static inline struct rq *__task_rq_lock(struct task_struct *p)
300 lockdep_assert_held(&p->pi_lock);
304 raw_spin_lock(&rq->lock);
305 if (likely(rq == task_rq(p)))
307 raw_spin_unlock(&rq->lock);
312 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
314 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
315 __acquires(p->pi_lock)
321 raw_spin_lock_irqsave(&p->pi_lock, *flags);
323 raw_spin_lock(&rq->lock);
324 if (likely(rq == task_rq(p)))
326 raw_spin_unlock(&rq->lock);
327 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
331 static void __task_rq_unlock(struct rq *rq)
334 raw_spin_unlock(&rq->lock);
338 task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
340 __releases(p->pi_lock)
342 raw_spin_unlock(&rq->lock);
343 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
347 * this_rq_lock - lock this runqueue and disable interrupts.
349 static struct rq *this_rq_lock(void)
356 raw_spin_lock(&rq->lock);
361 #ifdef CONFIG_SCHED_HRTICK
363 * Use HR-timers to deliver accurate preemption points.
365 * Its all a bit involved since we cannot program an hrt while holding the
366 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
369 * When we get rescheduled we reprogram the hrtick_timer outside of the
373 static void hrtick_clear(struct rq *rq)
375 if (hrtimer_active(&rq->hrtick_timer))
376 hrtimer_cancel(&rq->hrtick_timer);
380 * High-resolution timer tick.
381 * Runs from hardirq context with interrupts disabled.
383 static enum hrtimer_restart hrtick(struct hrtimer *timer)
385 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
387 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
389 raw_spin_lock(&rq->lock);
391 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
392 raw_spin_unlock(&rq->lock);
394 return HRTIMER_NORESTART;
399 * called from hardirq (IPI) context
401 static void __hrtick_start(void *arg)
405 raw_spin_lock(&rq->lock);
406 hrtimer_restart(&rq->hrtick_timer);
407 rq->hrtick_csd_pending = 0;
408 raw_spin_unlock(&rq->lock);
412 * Called to set the hrtick timer state.
414 * called with rq->lock held and irqs disabled
416 void hrtick_start(struct rq *rq, u64 delay)
418 struct hrtimer *timer = &rq->hrtick_timer;
419 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
421 hrtimer_set_expires(timer, time);
423 if (rq == this_rq()) {
424 hrtimer_restart(timer);
425 } else if (!rq->hrtick_csd_pending) {
426 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
427 rq->hrtick_csd_pending = 1;
432 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
434 int cpu = (int)(long)hcpu;
437 case CPU_UP_CANCELED:
438 case CPU_UP_CANCELED_FROZEN:
439 case CPU_DOWN_PREPARE:
440 case CPU_DOWN_PREPARE_FROZEN:
442 case CPU_DEAD_FROZEN:
443 hrtick_clear(cpu_rq(cpu));
450 static __init void init_hrtick(void)
452 hotcpu_notifier(hotplug_hrtick, 0);
456 * Called to set the hrtick timer state.
458 * called with rq->lock held and irqs disabled
460 void hrtick_start(struct rq *rq, u64 delay)
462 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
463 HRTIMER_MODE_REL_PINNED, 0);
466 static inline void init_hrtick(void)
469 #endif /* CONFIG_SMP */
471 static void init_rq_hrtick(struct rq *rq)
474 rq->hrtick_csd_pending = 0;
476 rq->hrtick_csd.flags = 0;
477 rq->hrtick_csd.func = __hrtick_start;
478 rq->hrtick_csd.info = rq;
481 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
482 rq->hrtick_timer.function = hrtick;
484 #else /* CONFIG_SCHED_HRTICK */
485 static inline void hrtick_clear(struct rq *rq)
489 static inline void init_rq_hrtick(struct rq *rq)
493 static inline void init_hrtick(void)
496 #endif /* CONFIG_SCHED_HRTICK */
499 * resched_task - mark a task 'to be rescheduled now'.
501 * On UP this means the setting of the need_resched flag, on SMP it
502 * might also involve a cross-CPU call to trigger the scheduler on
507 #ifndef tsk_is_polling
508 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
511 void resched_task(struct task_struct *p)
515 assert_raw_spin_locked(&task_rq(p)->lock);
517 if (test_tsk_need_resched(p))
520 set_tsk_need_resched(p);
523 if (cpu == smp_processor_id())
526 /* NEED_RESCHED must be visible before we test polling */
528 if (!tsk_is_polling(p))
529 smp_send_reschedule(cpu);
532 void resched_cpu(int cpu)
534 struct rq *rq = cpu_rq(cpu);
537 if (!raw_spin_trylock_irqsave(&rq->lock, flags))
539 resched_task(cpu_curr(cpu));
540 raw_spin_unlock_irqrestore(&rq->lock, flags);
545 * In the semi idle case, use the nearest busy cpu for migrating timers
546 * from an idle cpu. This is good for power-savings.
548 * We don't do similar optimization for completely idle system, as
549 * selecting an idle cpu will add more delays to the timers than intended
550 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
552 int get_nohz_timer_target(void)
554 int cpu = smp_processor_id();
556 struct sched_domain *sd;
559 for_each_domain(cpu, sd) {
560 for_each_cpu(i, sched_domain_span(sd)) {
572 * When add_timer_on() enqueues a timer into the timer wheel of an
573 * idle CPU then this timer might expire before the next timer event
574 * which is scheduled to wake up that CPU. In case of a completely
575 * idle system the next event might even be infinite time into the
576 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
577 * leaves the inner idle loop so the newly added timer is taken into
578 * account when the CPU goes back to idle and evaluates the timer
579 * wheel for the next timer event.
581 void wake_up_idle_cpu(int cpu)
583 struct rq *rq = cpu_rq(cpu);
585 if (cpu == smp_processor_id())
589 * This is safe, as this function is called with the timer
590 * wheel base lock of (cpu) held. When the CPU is on the way
591 * to idle and has not yet set rq->curr to idle then it will
592 * be serialized on the timer wheel base lock and take the new
593 * timer into account automatically.
595 if (rq->curr != rq->idle)
599 * We can set TIF_RESCHED on the idle task of the other CPU
600 * lockless. The worst case is that the other CPU runs the
601 * idle task through an additional NOOP schedule()
603 set_tsk_need_resched(rq->idle);
605 /* NEED_RESCHED must be visible before we test polling */
607 if (!tsk_is_polling(rq->idle))
608 smp_send_reschedule(cpu);
611 static inline bool got_nohz_idle_kick(void)
613 int cpu = smp_processor_id();
614 return idle_cpu(cpu) && test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));
617 #else /* CONFIG_NO_HZ */
619 static inline bool got_nohz_idle_kick(void)
624 #endif /* CONFIG_NO_HZ */
626 void sched_avg_update(struct rq *rq)
628 s64 period = sched_avg_period();
630 while ((s64)(rq->clock - rq->age_stamp) > period) {
632 * Inline assembly required to prevent the compiler
633 * optimising this loop into a divmod call.
634 * See __iter_div_u64_rem() for another example of this.
636 asm("" : "+rm" (rq->age_stamp));
637 rq->age_stamp += period;
642 #else /* !CONFIG_SMP */
643 void resched_task(struct task_struct *p)
645 assert_raw_spin_locked(&task_rq(p)->lock);
646 set_tsk_need_resched(p);
648 #endif /* CONFIG_SMP */
650 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
651 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
653 * Iterate task_group tree rooted at *from, calling @down when first entering a
654 * node and @up when leaving it for the final time.
656 * Caller must hold rcu_lock or sufficient equivalent.
658 int walk_tg_tree_from(struct task_group *from,
659 tg_visitor down, tg_visitor up, void *data)
661 struct task_group *parent, *child;
667 ret = (*down)(parent, data);
670 list_for_each_entry_rcu(child, &parent->children, siblings) {
677 ret = (*up)(parent, data);
678 if (ret || parent == from)
682 parent = parent->parent;
689 int tg_nop(struct task_group *tg, void *data)
695 static void set_load_weight(struct task_struct *p)
697 int prio = p->static_prio - MAX_RT_PRIO;
698 struct load_weight *load = &p->se.load;
701 * SCHED_IDLE tasks get minimal weight:
703 if (p->policy == SCHED_IDLE) {
704 load->weight = scale_load(WEIGHT_IDLEPRIO);
705 load->inv_weight = WMULT_IDLEPRIO;
709 load->weight = scale_load(prio_to_weight[prio]);
710 load->inv_weight = prio_to_wmult[prio];
713 static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
716 sched_info_queued(p);
717 p->sched_class->enqueue_task(rq, p, flags);
720 static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
723 sched_info_dequeued(p);
724 p->sched_class->dequeue_task(rq, p, flags);
727 void activate_task(struct rq *rq, struct task_struct *p, int flags)
729 if (task_contributes_to_load(p))
730 rq->nr_uninterruptible--;
732 enqueue_task(rq, p, flags);
735 void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
737 if (task_contributes_to_load(p))
738 rq->nr_uninterruptible++;
740 dequeue_task(rq, p, flags);
743 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
746 * There are no locks covering percpu hardirq/softirq time.
747 * They are only modified in account_system_vtime, on corresponding CPU
748 * with interrupts disabled. So, writes are safe.
749 * They are read and saved off onto struct rq in update_rq_clock().
750 * This may result in other CPU reading this CPU's irq time and can
751 * race with irq/account_system_vtime on this CPU. We would either get old
752 * or new value with a side effect of accounting a slice of irq time to wrong
753 * task when irq is in progress while we read rq->clock. That is a worthy
754 * compromise in place of having locks on each irq in account_system_time.
756 static DEFINE_PER_CPU(u64, cpu_hardirq_time);
757 static DEFINE_PER_CPU(u64, cpu_softirq_time);
759 static DEFINE_PER_CPU(u64, irq_start_time);
760 static int sched_clock_irqtime;
762 void enable_sched_clock_irqtime(void)
764 sched_clock_irqtime = 1;
767 void disable_sched_clock_irqtime(void)
769 sched_clock_irqtime = 0;
773 static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
775 static inline void irq_time_write_begin(void)
777 __this_cpu_inc(irq_time_seq.sequence);
781 static inline void irq_time_write_end(void)
784 __this_cpu_inc(irq_time_seq.sequence);
787 static inline u64 irq_time_read(int cpu)
793 seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
794 irq_time = per_cpu(cpu_softirq_time, cpu) +
795 per_cpu(cpu_hardirq_time, cpu);
796 } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));
800 #else /* CONFIG_64BIT */
801 static inline void irq_time_write_begin(void)
805 static inline void irq_time_write_end(void)
809 static inline u64 irq_time_read(int cpu)
811 return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
813 #endif /* CONFIG_64BIT */
816 * Called before incrementing preempt_count on {soft,}irq_enter
817 * and before decrementing preempt_count on {soft,}irq_exit.
819 void account_system_vtime(struct task_struct *curr)
825 if (!sched_clock_irqtime)
828 local_irq_save(flags);
830 cpu = smp_processor_id();
831 delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
832 __this_cpu_add(irq_start_time, delta);
834 irq_time_write_begin();
836 * We do not account for softirq time from ksoftirqd here.
837 * We want to continue accounting softirq time to ksoftirqd thread
838 * in that case, so as not to confuse scheduler with a special task
839 * that do not consume any time, but still wants to run.
842 __this_cpu_add(cpu_hardirq_time, delta);
843 else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
844 __this_cpu_add(cpu_softirq_time, delta);
846 irq_time_write_end();
847 local_irq_restore(flags);
849 EXPORT_SYMBOL_GPL(account_system_vtime);
851 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
853 #ifdef CONFIG_PARAVIRT
854 static inline u64 steal_ticks(u64 steal)
856 if (unlikely(steal > NSEC_PER_SEC))
857 return div_u64(steal, TICK_NSEC);
859 return __iter_div_u64_rem(steal, TICK_NSEC, &steal);
863 static void update_rq_clock_task(struct rq *rq, s64 delta)
866 * In theory, the compile should just see 0 here, and optimize out the call
867 * to sched_rt_avg_update. But I don't trust it...
869 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
870 s64 steal = 0, irq_delta = 0;
872 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
873 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
876 * Since irq_time is only updated on {soft,}irq_exit, we might run into
877 * this case when a previous update_rq_clock() happened inside a
880 * When this happens, we stop ->clock_task and only update the
881 * prev_irq_time stamp to account for the part that fit, so that a next
882 * update will consume the rest. This ensures ->clock_task is
885 * It does however cause some slight miss-attribution of {soft,}irq
886 * time, a more accurate solution would be to update the irq_time using
887 * the current rq->clock timestamp, except that would require using
890 if (irq_delta > delta)
893 rq->prev_irq_time += irq_delta;
896 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
897 if (static_key_false((¶virt_steal_rq_enabled))) {
900 steal = paravirt_steal_clock(cpu_of(rq));
901 steal -= rq->prev_steal_time_rq;
903 if (unlikely(steal > delta))
906 st = steal_ticks(steal);
907 steal = st * TICK_NSEC;
909 rq->prev_steal_time_rq += steal;
915 rq->clock_task += delta;
917 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
918 if ((irq_delta + steal) && sched_feat(NONTASK_POWER))
919 sched_rt_avg_update(rq, irq_delta + steal);
923 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
924 static int irqtime_account_hi_update(void)
926 u64 *cpustat = kcpustat_this_cpu->cpustat;
931 local_irq_save(flags);
932 latest_ns = this_cpu_read(cpu_hardirq_time);
933 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ])
935 local_irq_restore(flags);
939 static int irqtime_account_si_update(void)
941 u64 *cpustat = kcpustat_this_cpu->cpustat;
946 local_irq_save(flags);
947 latest_ns = this_cpu_read(cpu_softirq_time);
948 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ])
950 local_irq_restore(flags);
954 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
956 #define sched_clock_irqtime (0)
960 void sched_set_stop_task(int cpu, struct task_struct *stop)
962 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
963 struct task_struct *old_stop = cpu_rq(cpu)->stop;
967 * Make it appear like a SCHED_FIFO task, its something
968 * userspace knows about and won't get confused about.
970 * Also, it will make PI more or less work without too
971 * much confusion -- but then, stop work should not
972 * rely on PI working anyway.
974 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m);
976 stop->sched_class = &stop_sched_class;
979 cpu_rq(cpu)->stop = stop;
983 * Reset it back to a normal scheduling class so that
984 * it can die in pieces.
986 old_stop->sched_class = &rt_sched_class;
991 * __normal_prio - return the priority that is based on the static prio
993 static inline int __normal_prio(struct task_struct *p)
995 return p->static_prio;
999 * Calculate the expected normal priority: i.e. priority
1000 * without taking RT-inheritance into account. Might be
1001 * boosted by interactivity modifiers. Changes upon fork,
1002 * setprio syscalls, and whenever the interactivity
1003 * estimator recalculates.
1005 static inline int normal_prio(struct task_struct *p)
1009 if (task_has_rt_policy(p))
1010 prio = MAX_RT_PRIO-1 - p->rt_priority;
1012 prio = __normal_prio(p);
1017 * Calculate the current priority, i.e. the priority
1018 * taken into account by the scheduler. This value might
1019 * be boosted by RT tasks, or might be boosted by
1020 * interactivity modifiers. Will be RT if the task got
1021 * RT-boosted. If not then it returns p->normal_prio.
1023 static int effective_prio(struct task_struct *p)
1025 p->normal_prio = normal_prio(p);
1027 * If we are RT tasks or we were boosted to RT priority,
1028 * keep the priority unchanged. Otherwise, update priority
1029 * to the normal priority:
1031 if (!rt_prio(p->prio))
1032 return p->normal_prio;
1037 * task_curr - is this task currently executing on a CPU?
1038 * @p: the task in question.
1040 inline int task_curr(const struct task_struct *p)
1042 return cpu_curr(task_cpu(p)) == p;
1045 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1046 const struct sched_class *prev_class,
1049 if (prev_class != p->sched_class) {
1050 if (prev_class->switched_from)
1051 prev_class->switched_from(rq, p);
1052 p->sched_class->switched_to(rq, p);
1053 } else if (oldprio != p->prio)
1054 p->sched_class->prio_changed(rq, p, oldprio);
1057 void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
1059 const struct sched_class *class;
1061 if (p->sched_class == rq->curr->sched_class) {
1062 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
1064 for_each_class(class) {
1065 if (class == rq->curr->sched_class)
1067 if (class == p->sched_class) {
1068 resched_task(rq->curr);
1075 * A queue event has occurred, and we're going to schedule. In
1076 * this case, we can save a useless back to back clock update.
1078 if (rq->curr->on_rq && test_tsk_need_resched(rq->curr))
1079 rq->skip_clock_update = 1;
1083 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1085 #ifdef CONFIG_SCHED_DEBUG
1087 * We should never call set_task_cpu() on a blocked task,
1088 * ttwu() will sort out the placement.
1090 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
1091 !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE));
1093 #ifdef CONFIG_LOCKDEP
1095 * The caller should hold either p->pi_lock or rq->lock, when changing
1096 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1098 * sched_move_task() holds both and thus holding either pins the cgroup,
1099 * see set_task_rq().
1101 * Furthermore, all task_rq users should acquire both locks, see
1104 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
1105 lockdep_is_held(&task_rq(p)->lock)));
1109 trace_sched_migrate_task(p, new_cpu);
1111 if (task_cpu(p) != new_cpu) {
1112 p->se.nr_migrations++;
1113 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);
1116 __set_task_cpu(p, new_cpu);
1119 struct migration_arg {
1120 struct task_struct *task;
1124 static int migration_cpu_stop(void *data);
1127 * wait_task_inactive - wait for a thread to unschedule.
1129 * If @match_state is nonzero, it's the @p->state value just checked and
1130 * not expected to change. If it changes, i.e. @p might have woken up,
1131 * then return zero. When we succeed in waiting for @p to be off its CPU,
1132 * we return a positive number (its total switch count). If a second call
1133 * a short while later returns the same number, the caller can be sure that
1134 * @p has remained unscheduled the whole time.
1136 * The caller must ensure that the task *will* unschedule sometime soon,
1137 * else this function might spin for a *long* time. This function can't
1138 * be called with interrupts off, or it may introduce deadlock with
1139 * smp_call_function() if an IPI is sent by the same process we are
1140 * waiting to become inactive.
1142 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1144 unsigned long flags;
1151 * We do the initial early heuristics without holding
1152 * any task-queue locks at all. We'll only try to get
1153 * the runqueue lock when things look like they will
1159 * If the task is actively running on another CPU
1160 * still, just relax and busy-wait without holding
1163 * NOTE! Since we don't hold any locks, it's not
1164 * even sure that "rq" stays as the right runqueue!
1165 * But we don't care, since "task_running()" will
1166 * return false if the runqueue has changed and p
1167 * is actually now running somewhere else!
1169 while (task_running(rq, p)) {
1170 if (match_state && unlikely(p->state != match_state))
1176 * Ok, time to look more closely! We need the rq
1177 * lock now, to be *sure*. If we're wrong, we'll
1178 * just go back and repeat.
1180 rq = task_rq_lock(p, &flags);
1181 trace_sched_wait_task(p);
1182 running = task_running(rq, p);
1185 if (!match_state || p->state == match_state)
1186 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1187 task_rq_unlock(rq, p, &flags);
1190 * If it changed from the expected state, bail out now.
1192 if (unlikely(!ncsw))
1196 * Was it really running after all now that we
1197 * checked with the proper locks actually held?
1199 * Oops. Go back and try again..
1201 if (unlikely(running)) {
1207 * It's not enough that it's not actively running,
1208 * it must be off the runqueue _entirely_, and not
1211 * So if it was still runnable (but just not actively
1212 * running right now), it's preempted, and we should
1213 * yield - it could be a while.
1215 if (unlikely(on_rq)) {
1216 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
1218 set_current_state(TASK_UNINTERRUPTIBLE);
1219 schedule_hrtimeout(&to, HRTIMER_MODE_REL);
1224 * Ahh, all good. It wasn't running, and it wasn't
1225 * runnable, which means that it will never become
1226 * running in the future either. We're all done!
1235 * kick_process - kick a running thread to enter/exit the kernel
1236 * @p: the to-be-kicked thread
1238 * Cause a process which is running on another CPU to enter
1239 * kernel-mode, without any delay. (to get signals handled.)
1241 * NOTE: this function doesn't have to take the runqueue lock,
1242 * because all it wants to ensure is that the remote task enters
1243 * the kernel. If the IPI races and the task has been migrated
1244 * to another CPU then no harm is done and the purpose has been
1247 void kick_process(struct task_struct *p)
1253 if ((cpu != smp_processor_id()) && task_curr(p))
1254 smp_send_reschedule(cpu);
1257 EXPORT_SYMBOL_GPL(kick_process);
1258 #endif /* CONFIG_SMP */
1262 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1264 static int select_fallback_rq(int cpu, struct task_struct *p)
1266 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(cpu));
1267 enum { cpuset, possible, fail } state = cpuset;
1270 /* Look for allowed, online CPU in same node. */
1271 for_each_cpu(dest_cpu, nodemask) {
1272 if (!cpu_online(dest_cpu))
1274 if (!cpu_active(dest_cpu))
1276 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
1281 /* Any allowed, online CPU? */
1282 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) {
1283 if (!cpu_online(dest_cpu))
1285 if (!cpu_active(dest_cpu))
1292 /* No more Mr. Nice Guy. */
1293 cpuset_cpus_allowed_fallback(p);
1298 do_set_cpus_allowed(p, cpu_possible_mask);
1309 if (state != cpuset) {
1311 * Don't tell them about moving exiting tasks or
1312 * kernel threads (both mm NULL), since they never
1315 if (p->mm && printk_ratelimit()) {
1316 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1317 task_pid_nr(p), p->comm, cpu);
1325 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1328 int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
1330 int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags);
1333 * In order not to call set_task_cpu() on a blocking task we need
1334 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1337 * Since this is common to all placement strategies, this lives here.
1339 * [ this allows ->select_task() to simply return task_cpu(p) and
1340 * not worry about this generic constraint ]
1342 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
1344 cpu = select_fallback_rq(task_cpu(p), p);
1349 static void update_avg(u64 *avg, u64 sample)
1351 s64 diff = sample - *avg;
1357 ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
1359 #ifdef CONFIG_SCHEDSTATS
1360 struct rq *rq = this_rq();
1363 int this_cpu = smp_processor_id();
1365 if (cpu == this_cpu) {
1366 schedstat_inc(rq, ttwu_local);
1367 schedstat_inc(p, se.statistics.nr_wakeups_local);
1369 struct sched_domain *sd;
1371 schedstat_inc(p, se.statistics.nr_wakeups_remote);
1373 for_each_domain(this_cpu, sd) {
1374 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
1375 schedstat_inc(sd, ttwu_wake_remote);
1382 if (wake_flags & WF_MIGRATED)
1383 schedstat_inc(p, se.statistics.nr_wakeups_migrate);
1385 #endif /* CONFIG_SMP */
1387 schedstat_inc(rq, ttwu_count);
1388 schedstat_inc(p, se.statistics.nr_wakeups);
1390 if (wake_flags & WF_SYNC)
1391 schedstat_inc(p, se.statistics.nr_wakeups_sync);
1393 #endif /* CONFIG_SCHEDSTATS */
1396 static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
1398 activate_task(rq, p, en_flags);
1401 /* if a worker is waking up, notify workqueue */
1402 if (p->flags & PF_WQ_WORKER)
1403 wq_worker_waking_up(p, cpu_of(rq));
1407 * Mark the task runnable and perform wakeup-preemption.
1410 ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
1412 trace_sched_wakeup(p, true);
1413 check_preempt_curr(rq, p, wake_flags);
1415 p->state = TASK_RUNNING;
1417 if (p->sched_class->task_woken)
1418 p->sched_class->task_woken(rq, p);
1420 if (rq->idle_stamp) {
1421 u64 delta = rq->clock - rq->idle_stamp;
1422 u64 max = 2*sysctl_sched_migration_cost;
1427 update_avg(&rq->avg_idle, delta);
1434 ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
1437 if (p->sched_contributes_to_load)
1438 rq->nr_uninterruptible--;
1441 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
1442 ttwu_do_wakeup(rq, p, wake_flags);
1446 * Called in case the task @p isn't fully descheduled from its runqueue,
1447 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1448 * since all we need to do is flip p->state to TASK_RUNNING, since
1449 * the task is still ->on_rq.
1451 static int ttwu_remote(struct task_struct *p, int wake_flags)
1456 rq = __task_rq_lock(p);
1458 ttwu_do_wakeup(rq, p, wake_flags);
1461 __task_rq_unlock(rq);
1467 static void sched_ttwu_pending(void)
1469 struct rq *rq = this_rq();
1470 struct llist_node *llist = llist_del_all(&rq->wake_list);
1471 struct task_struct *p;
1473 raw_spin_lock(&rq->lock);
1476 p = llist_entry(llist, struct task_struct, wake_entry);
1477 llist = llist_next(llist);
1478 ttwu_do_activate(rq, p, 0);
1481 raw_spin_unlock(&rq->lock);
1484 void scheduler_ipi(void)
1486 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
1490 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1491 * traditionally all their work was done from the interrupt return
1492 * path. Now that we actually do some work, we need to make sure
1495 * Some archs already do call them, luckily irq_enter/exit nest
1498 * Arguably we should visit all archs and update all handlers,
1499 * however a fair share of IPIs are still resched only so this would
1500 * somewhat pessimize the simple resched case.
1503 sched_ttwu_pending();
1506 * Check if someone kicked us for doing the nohz idle load balance.
1508 if (unlikely(got_nohz_idle_kick() && !need_resched())) {
1509 this_rq()->idle_balance = 1;
1510 raise_softirq_irqoff(SCHED_SOFTIRQ);
1515 static void ttwu_queue_remote(struct task_struct *p, int cpu)
1517 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list))
1518 smp_send_reschedule(cpu);
1521 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1522 static int ttwu_activate_remote(struct task_struct *p, int wake_flags)
1527 rq = __task_rq_lock(p);
1529 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
1530 ttwu_do_wakeup(rq, p, wake_flags);
1533 __task_rq_unlock(rq);
1538 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1540 bool cpus_share_cache(int this_cpu, int that_cpu)
1542 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
1544 #endif /* CONFIG_SMP */
1546 static void ttwu_queue(struct task_struct *p, int cpu)
1548 struct rq *rq = cpu_rq(cpu);
1550 #if defined(CONFIG_SMP)
1551 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) {
1552 sched_clock_cpu(cpu); /* sync clocks x-cpu */
1553 ttwu_queue_remote(p, cpu);
1558 raw_spin_lock(&rq->lock);
1559 ttwu_do_activate(rq, p, 0);
1560 raw_spin_unlock(&rq->lock);
1564 * try_to_wake_up - wake up a thread
1565 * @p: the thread to be awakened
1566 * @state: the mask of task states that can be woken
1567 * @wake_flags: wake modifier flags (WF_*)
1569 * Put it on the run-queue if it's not already there. The "current"
1570 * thread is always on the run-queue (except when the actual
1571 * re-schedule is in progress), and as such you're allowed to do
1572 * the simpler "current->state = TASK_RUNNING" to mark yourself
1573 * runnable without the overhead of this.
1575 * Returns %true if @p was woken up, %false if it was already running
1576 * or @state didn't match @p's state.
1579 try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
1581 unsigned long flags;
1582 int cpu, success = 0;
1585 raw_spin_lock_irqsave(&p->pi_lock, flags);
1586 if (!(p->state & state))
1589 success = 1; /* we're going to change ->state */
1592 if (p->on_rq && ttwu_remote(p, wake_flags))
1597 * If the owning (remote) cpu is still in the middle of schedule() with
1598 * this task as prev, wait until its done referencing the task.
1601 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1603 * In case the architecture enables interrupts in
1604 * context_switch(), we cannot busy wait, since that
1605 * would lead to deadlocks when an interrupt hits and
1606 * tries to wake up @prev. So bail and do a complete
1609 if (ttwu_activate_remote(p, wake_flags))
1616 * Pairs with the smp_wmb() in finish_lock_switch().
1620 p->sched_contributes_to_load = !!task_contributes_to_load(p);
1621 p->state = TASK_WAKING;
1623 if (p->sched_class->task_waking)
1624 p->sched_class->task_waking(p);
1626 cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
1627 if (task_cpu(p) != cpu) {
1628 wake_flags |= WF_MIGRATED;
1629 set_task_cpu(p, cpu);
1631 #endif /* CONFIG_SMP */
1635 ttwu_stat(p, cpu, wake_flags);
1637 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1643 * try_to_wake_up_local - try to wake up a local task with rq lock held
1644 * @p: the thread to be awakened
1646 * Put @p on the run-queue if it's not already there. The caller must
1647 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1650 static void try_to_wake_up_local(struct task_struct *p)
1652 struct rq *rq = task_rq(p);
1654 BUG_ON(rq != this_rq());
1655 BUG_ON(p == current);
1656 lockdep_assert_held(&rq->lock);
1658 if (!raw_spin_trylock(&p->pi_lock)) {
1659 raw_spin_unlock(&rq->lock);
1660 raw_spin_lock(&p->pi_lock);
1661 raw_spin_lock(&rq->lock);
1664 if (!(p->state & TASK_NORMAL))
1668 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
1670 ttwu_do_wakeup(rq, p, 0);
1671 ttwu_stat(p, smp_processor_id(), 0);
1673 raw_spin_unlock(&p->pi_lock);
1677 * wake_up_process - Wake up a specific process
1678 * @p: The process to be woken up.
1680 * Attempt to wake up the nominated process and move it to the set of runnable
1681 * processes. Returns 1 if the process was woken up, 0 if it was already
1684 * It may be assumed that this function implies a write memory barrier before
1685 * changing the task state if and only if any tasks are woken up.
1687 int wake_up_process(struct task_struct *p)
1689 return try_to_wake_up(p, TASK_ALL, 0);
1691 EXPORT_SYMBOL(wake_up_process);
1693 int wake_up_state(struct task_struct *p, unsigned int state)
1695 return try_to_wake_up(p, state, 0);
1699 * Perform scheduler related setup for a newly forked process p.
1700 * p is forked by current.
1702 * __sched_fork() is basic setup used by init_idle() too:
1704 static void __sched_fork(struct task_struct *p)
1709 p->se.exec_start = 0;
1710 p->se.sum_exec_runtime = 0;
1711 p->se.prev_sum_exec_runtime = 0;
1712 p->se.nr_migrations = 0;
1714 INIT_LIST_HEAD(&p->se.group_node);
1716 #ifdef CONFIG_SCHEDSTATS
1717 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
1720 INIT_LIST_HEAD(&p->rt.run_list);
1722 #ifdef CONFIG_PREEMPT_NOTIFIERS
1723 INIT_HLIST_HEAD(&p->preempt_notifiers);
1728 * fork()/clone()-time setup:
1730 void sched_fork(struct task_struct *p)
1732 unsigned long flags;
1733 int cpu = get_cpu();
1737 * We mark the process as running here. This guarantees that
1738 * nobody will actually run it, and a signal or other external
1739 * event cannot wake it up and insert it on the runqueue either.
1741 p->state = TASK_RUNNING;
1744 * Make sure we do not leak PI boosting priority to the child.
1746 p->prio = current->normal_prio;
1749 * Revert to default priority/policy on fork if requested.
1751 if (unlikely(p->sched_reset_on_fork)) {
1752 if (task_has_rt_policy(p)) {
1753 p->policy = SCHED_NORMAL;
1754 p->static_prio = NICE_TO_PRIO(0);
1756 } else if (PRIO_TO_NICE(p->static_prio) < 0)
1757 p->static_prio = NICE_TO_PRIO(0);
1759 p->prio = p->normal_prio = __normal_prio(p);
1763 * We don't need the reset flag anymore after the fork. It has
1764 * fulfilled its duty:
1766 p->sched_reset_on_fork = 0;
1769 if (!rt_prio(p->prio))
1770 p->sched_class = &fair_sched_class;
1772 if (p->sched_class->task_fork)
1773 p->sched_class->task_fork(p);
1776 * The child is not yet in the pid-hash so no cgroup attach races,
1777 * and the cgroup is pinned to this child due to cgroup_fork()
1778 * is ran before sched_fork().
1780 * Silence PROVE_RCU.
1782 raw_spin_lock_irqsave(&p->pi_lock, flags);
1783 set_task_cpu(p, cpu);
1784 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1786 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1787 if (likely(sched_info_on()))
1788 memset(&p->sched_info, 0, sizeof(p->sched_info));
1790 #if defined(CONFIG_SMP)
1793 #ifdef CONFIG_PREEMPT_COUNT
1794 /* Want to start with kernel preemption disabled. */
1795 task_thread_info(p)->preempt_count = 1;
1798 plist_node_init(&p->pushable_tasks, MAX_PRIO);
1805 * wake_up_new_task - wake up a newly created task for the first time.
1807 * This function will do some initial scheduler statistics housekeeping
1808 * that must be done for every newly created context, then puts the task
1809 * on the runqueue and wakes it.
1811 void wake_up_new_task(struct task_struct *p)
1813 unsigned long flags;
1816 raw_spin_lock_irqsave(&p->pi_lock, flags);
1819 * Fork balancing, do it here and not earlier because:
1820 * - cpus_allowed can change in the fork path
1821 * - any previously selected cpu might disappear through hotplug
1823 set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0));
1826 rq = __task_rq_lock(p);
1827 activate_task(rq, p, 0);
1829 trace_sched_wakeup_new(p, true);
1830 check_preempt_curr(rq, p, WF_FORK);
1832 if (p->sched_class->task_woken)
1833 p->sched_class->task_woken(rq, p);
1835 task_rq_unlock(rq, p, &flags);
1838 #ifdef CONFIG_PREEMPT_NOTIFIERS
1841 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1842 * @notifier: notifier struct to register
1844 void preempt_notifier_register(struct preempt_notifier *notifier)
1846 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
1848 EXPORT_SYMBOL_GPL(preempt_notifier_register);
1851 * preempt_notifier_unregister - no longer interested in preemption notifications
1852 * @notifier: notifier struct to unregister
1854 * This is safe to call from within a preemption notifier.
1856 void preempt_notifier_unregister(struct preempt_notifier *notifier)
1858 hlist_del(¬ifier->link);
1860 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
1862 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1864 struct preempt_notifier *notifier;
1865 struct hlist_node *node;
1867 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
1868 notifier->ops->sched_in(notifier, raw_smp_processor_id());
1872 fire_sched_out_preempt_notifiers(struct task_struct *curr,
1873 struct task_struct *next)
1875 struct preempt_notifier *notifier;
1876 struct hlist_node *node;
1878 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
1879 notifier->ops->sched_out(notifier, next);
1882 #else /* !CONFIG_PREEMPT_NOTIFIERS */
1884 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1889 fire_sched_out_preempt_notifiers(struct task_struct *curr,
1890 struct task_struct *next)
1894 #endif /* CONFIG_PREEMPT_NOTIFIERS */
1897 * prepare_task_switch - prepare to switch tasks
1898 * @rq: the runqueue preparing to switch
1899 * @prev: the current task that is being switched out
1900 * @next: the task we are going to switch to.
1902 * This is called with the rq lock held and interrupts off. It must
1903 * be paired with a subsequent finish_task_switch after the context
1906 * prepare_task_switch sets up locking and calls architecture specific
1910 prepare_task_switch(struct rq *rq, struct task_struct *prev,
1911 struct task_struct *next)
1913 sched_info_switch(prev, next);
1914 perf_event_task_sched_out(prev, next);
1915 fire_sched_out_preempt_notifiers(prev, next);
1916 prepare_lock_switch(rq, next);
1917 prepare_arch_switch(next);
1918 trace_sched_switch(prev, next);
1922 * finish_task_switch - clean up after a task-switch
1923 * @rq: runqueue associated with task-switch
1924 * @prev: the thread we just switched away from.
1926 * finish_task_switch must be called after the context switch, paired
1927 * with a prepare_task_switch call before the context switch.
1928 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1929 * and do any other architecture-specific cleanup actions.
1931 * Note that we may have delayed dropping an mm in context_switch(). If
1932 * so, we finish that here outside of the runqueue lock. (Doing it
1933 * with the lock held can cause deadlocks; see schedule() for
1936 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
1937 __releases(rq->lock)
1939 struct mm_struct *mm = rq->prev_mm;
1945 * A task struct has one reference for the use as "current".
1946 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1947 * schedule one last time. The schedule call will never return, and
1948 * the scheduled task must drop that reference.
1949 * The test for TASK_DEAD must occur while the runqueue locks are
1950 * still held, otherwise prev could be scheduled on another cpu, die
1951 * there before we look at prev->state, and then the reference would
1953 * Manfred Spraul <manfred@colorfullife.com>
1955 prev_state = prev->state;
1956 finish_arch_switch(prev);
1957 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1958 local_irq_disable();
1959 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1960 perf_event_task_sched_in(prev, current);
1961 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1963 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1964 finish_lock_switch(rq, prev);
1965 finish_arch_post_lock_switch();
1967 fire_sched_in_preempt_notifiers(current);
1970 if (unlikely(prev_state == TASK_DEAD)) {
1972 * Remove function-return probe instances associated with this
1973 * task and put them back on the free list.
1975 kprobe_flush_task(prev);
1976 put_task_struct(prev);
1982 /* assumes rq->lock is held */
1983 static inline void pre_schedule(struct rq *rq, struct task_struct *prev)
1985 if (prev->sched_class->pre_schedule)
1986 prev->sched_class->pre_schedule(rq, prev);
1989 /* rq->lock is NOT held, but preemption is disabled */
1990 static inline void post_schedule(struct rq *rq)
1992 if (rq->post_schedule) {
1993 unsigned long flags;
1995 raw_spin_lock_irqsave(&rq->lock, flags);
1996 if (rq->curr->sched_class->post_schedule)
1997 rq->curr->sched_class->post_schedule(rq);
1998 raw_spin_unlock_irqrestore(&rq->lock, flags);
2000 rq->post_schedule = 0;
2006 static inline void pre_schedule(struct rq *rq, struct task_struct *p)
2010 static inline void post_schedule(struct rq *rq)
2017 * schedule_tail - first thing a freshly forked thread must call.
2018 * @prev: the thread we just switched away from.
2020 asmlinkage void schedule_tail(struct task_struct *prev)
2021 __releases(rq->lock)
2023 struct rq *rq = this_rq();
2025 finish_task_switch(rq, prev);
2028 * FIXME: do we need to worry about rq being invalidated by the
2033 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2034 /* In this case, finish_task_switch does not reenable preemption */
2037 if (current->set_child_tid)
2038 put_user(task_pid_vnr(current), current->set_child_tid);
2042 * context_switch - switch to the new MM and the new
2043 * thread's register state.
2046 context_switch(struct rq *rq, struct task_struct *prev,
2047 struct task_struct *next)
2049 struct mm_struct *mm, *oldmm;
2051 prepare_task_switch(rq, prev, next);
2054 oldmm = prev->active_mm;
2056 * For paravirt, this is coupled with an exit in switch_to to
2057 * combine the page table reload and the switch backend into
2060 arch_start_context_switch(prev);
2063 next->active_mm = oldmm;
2064 atomic_inc(&oldmm->mm_count);
2065 enter_lazy_tlb(oldmm, next);
2067 switch_mm(oldmm, mm, next);
2070 prev->active_mm = NULL;
2071 rq->prev_mm = oldmm;
2074 * Since the runqueue lock will be released by the next
2075 * task (which is an invalid locking op but in the case
2076 * of the scheduler it's an obvious special-case), so we
2077 * do an early lockdep release here:
2079 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2080 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2083 /* Here we just switch the register state and the stack. */
2084 rcu_switch_from(prev);
2085 switch_to(prev, next, prev);
2089 * this_rq must be evaluated again because prev may have moved
2090 * CPUs since it called schedule(), thus the 'rq' on its stack
2091 * frame will be invalid.
2093 finish_task_switch(this_rq(), prev);
2097 * nr_running, nr_uninterruptible and nr_context_switches:
2099 * externally visible scheduler statistics: current number of runnable
2100 * threads, current number of uninterruptible-sleeping threads, total
2101 * number of context switches performed since bootup.
2103 unsigned long nr_running(void)
2105 unsigned long i, sum = 0;
2107 for_each_online_cpu(i)
2108 sum += cpu_rq(i)->nr_running;
2113 unsigned long nr_uninterruptible(void)
2115 unsigned long i, sum = 0;
2117 for_each_possible_cpu(i)
2118 sum += cpu_rq(i)->nr_uninterruptible;
2121 * Since we read the counters lockless, it might be slightly
2122 * inaccurate. Do not allow it to go below zero though:
2124 if (unlikely((long)sum < 0))
2130 unsigned long long nr_context_switches(void)
2133 unsigned long long sum = 0;
2135 for_each_possible_cpu(i)
2136 sum += cpu_rq(i)->nr_switches;
2141 unsigned long nr_iowait(void)
2143 unsigned long i, sum = 0;
2145 for_each_possible_cpu(i)
2146 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2151 unsigned long nr_iowait_cpu(int cpu)
2153 struct rq *this = cpu_rq(cpu);
2154 return atomic_read(&this->nr_iowait);
2157 unsigned long this_cpu_load(void)
2159 struct rq *this = this_rq();
2160 return this->cpu_load[0];
2165 * Global load-average calculations
2167 * We take a distributed and async approach to calculating the global load-avg
2168 * in order to minimize overhead.
2170 * The global load average is an exponentially decaying average of nr_running +
2171 * nr_uninterruptible.
2173 * Once every LOAD_FREQ:
2176 * for_each_possible_cpu(cpu)
2177 * nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible;
2179 * avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n)
2181 * Due to a number of reasons the above turns in the mess below:
2183 * - for_each_possible_cpu() is prohibitively expensive on machines with
2184 * serious number of cpus, therefore we need to take a distributed approach
2185 * to calculating nr_active.
2187 * \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0
2188 * = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) }
2190 * So assuming nr_active := 0 when we start out -- true per definition, we
2191 * can simply take per-cpu deltas and fold those into a global accumulate
2192 * to obtain the same result. See calc_load_fold_active().
2194 * Furthermore, in order to avoid synchronizing all per-cpu delta folding
2195 * across the machine, we assume 10 ticks is sufficient time for every
2196 * cpu to have completed this task.
2198 * This places an upper-bound on the IRQ-off latency of the machine. Then
2199 * again, being late doesn't loose the delta, just wrecks the sample.
2201 * - cpu_rq()->nr_uninterruptible isn't accurately tracked per-cpu because
2202 * this would add another cross-cpu cacheline miss and atomic operation
2203 * to the wakeup path. Instead we increment on whatever cpu the task ran
2204 * when it went into uninterruptible state and decrement on whatever cpu
2205 * did the wakeup. This means that only the sum of nr_uninterruptible over
2206 * all cpus yields the correct result.
2208 * This covers the NO_HZ=n code, for extra head-aches, see the comment below.
2211 /* Variables and functions for calc_load */
2212 static atomic_long_t calc_load_tasks;
2213 static unsigned long calc_load_update;
2214 unsigned long avenrun[3];
2215 EXPORT_SYMBOL(avenrun); /* should be removed */
2218 * get_avenrun - get the load average array
2219 * @loads: pointer to dest load array
2220 * @offset: offset to add
2221 * @shift: shift count to shift the result left
2223 * These values are estimates at best, so no need for locking.
2225 void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
2227 loads[0] = (avenrun[0] + offset) << shift;
2228 loads[1] = (avenrun[1] + offset) << shift;
2229 loads[2] = (avenrun[2] + offset) << shift;
2232 static long calc_load_fold_active(struct rq *this_rq)
2234 long nr_active, delta = 0;
2236 nr_active = this_rq->nr_running;
2237 nr_active += (long) this_rq->nr_uninterruptible;
2239 if (nr_active != this_rq->calc_load_active) {
2240 delta = nr_active - this_rq->calc_load_active;
2241 this_rq->calc_load_active = nr_active;
2248 * a1 = a0 * e + a * (1 - e)
2250 static unsigned long
2251 calc_load(unsigned long load, unsigned long exp, unsigned long active)
2254 load += active * (FIXED_1 - exp);
2255 load += 1UL << (FSHIFT - 1);
2256 return load >> FSHIFT;
2261 * Handle NO_HZ for the global load-average.
2263 * Since the above described distributed algorithm to compute the global
2264 * load-average relies on per-cpu sampling from the tick, it is affected by
2267 * The basic idea is to fold the nr_active delta into a global idle-delta upon
2268 * entering NO_HZ state such that we can include this as an 'extra' cpu delta
2269 * when we read the global state.
2271 * Obviously reality has to ruin such a delightfully simple scheme:
2273 * - When we go NO_HZ idle during the window, we can negate our sample
2274 * contribution, causing under-accounting.
2276 * We avoid this by keeping two idle-delta counters and flipping them
2277 * when the window starts, thus separating old and new NO_HZ load.
2279 * The only trick is the slight shift in index flip for read vs write.
2283 * |-|-----------|-|-----------|-|-----------|-|
2284 * r:0 0 1 1 0 0 1 1 0
2285 * w:0 1 1 0 0 1 1 0 0
2287 * This ensures we'll fold the old idle contribution in this window while
2288 * accumlating the new one.
2290 * - When we wake up from NO_HZ idle during the window, we push up our
2291 * contribution, since we effectively move our sample point to a known
2294 * This is solved by pushing the window forward, and thus skipping the
2295 * sample, for this cpu (effectively using the idle-delta for this cpu which
2296 * was in effect at the time the window opened). This also solves the issue
2297 * of having to deal with a cpu having been in NOHZ idle for multiple
2298 * LOAD_FREQ intervals.
2300 * When making the ILB scale, we should try to pull this in as well.
2302 static atomic_long_t calc_load_idle[2];
2303 static int calc_load_idx;
2305 static inline int calc_load_write_idx(void)
2307 int idx = calc_load_idx;
2310 * See calc_global_nohz(), if we observe the new index, we also
2311 * need to observe the new update time.
2316 * If the folding window started, make sure we start writing in the
2319 if (!time_before(jiffies, calc_load_update))
2325 static inline int calc_load_read_idx(void)
2327 return calc_load_idx & 1;
2330 void calc_load_enter_idle(void)
2332 struct rq *this_rq = this_rq();
2336 * We're going into NOHZ mode, if there's any pending delta, fold it
2337 * into the pending idle delta.
2339 delta = calc_load_fold_active(this_rq);
2341 int idx = calc_load_write_idx();
2342 atomic_long_add(delta, &calc_load_idle[idx]);
2346 void calc_load_exit_idle(void)
2348 struct rq *this_rq = this_rq();
2351 * If we're still before the sample window, we're done.
2353 if (time_before(jiffies, this_rq->calc_load_update))
2357 * We woke inside or after the sample window, this means we're already
2358 * accounted through the nohz accounting, so skip the entire deal and
2359 * sync up for the next window.
2361 this_rq->calc_load_update = calc_load_update;
2362 if (time_before(jiffies, this_rq->calc_load_update + 10))
2363 this_rq->calc_load_update += LOAD_FREQ;
2366 static long calc_load_fold_idle(void)
2368 int idx = calc_load_read_idx();
2371 if (atomic_long_read(&calc_load_idle[idx]))
2372 delta = atomic_long_xchg(&calc_load_idle[idx], 0);
2378 * fixed_power_int - compute: x^n, in O(log n) time
2380 * @x: base of the power
2381 * @frac_bits: fractional bits of @x
2382 * @n: power to raise @x to.
2384 * By exploiting the relation between the definition of the natural power
2385 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
2386 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
2387 * (where: n_i \elem {0, 1}, the binary vector representing n),
2388 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
2389 * of course trivially computable in O(log_2 n), the length of our binary
2392 static unsigned long
2393 fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
2395 unsigned long result = 1UL << frac_bits;
2400 result += 1UL << (frac_bits - 1);
2401 result >>= frac_bits;
2407 x += 1UL << (frac_bits - 1);
2415 * a1 = a0 * e + a * (1 - e)
2417 * a2 = a1 * e + a * (1 - e)
2418 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
2419 * = a0 * e^2 + a * (1 - e) * (1 + e)
2421 * a3 = a2 * e + a * (1 - e)
2422 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
2423 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
2427 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
2428 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
2429 * = a0 * e^n + a * (1 - e^n)
2431 * [1] application of the geometric series:
2434 * S_n := \Sum x^i = -------------
2437 static unsigned long
2438 calc_load_n(unsigned long load, unsigned long exp,
2439 unsigned long active, unsigned int n)
2442 return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
2446 * NO_HZ can leave us missing all per-cpu ticks calling
2447 * calc_load_account_active(), but since an idle CPU folds its delta into
2448 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
2449 * in the pending idle delta if our idle period crossed a load cycle boundary.
2451 * Once we've updated the global active value, we need to apply the exponential
2452 * weights adjusted to the number of cycles missed.
2454 static void calc_global_nohz(void)
2456 long delta, active, n;
2458 if (!time_before(jiffies, calc_load_update + 10)) {
2460 * Catch-up, fold however many we are behind still
2462 delta = jiffies - calc_load_update - 10;
2463 n = 1 + (delta / LOAD_FREQ);
2465 active = atomic_long_read(&calc_load_tasks);
2466 active = active > 0 ? active * FIXED_1 : 0;
2468 avenrun[0] = calc_load_n(avenrun[0], EXP_1, active, n);
2469 avenrun[1] = calc_load_n(avenrun[1], EXP_5, active, n);
2470 avenrun[2] = calc_load_n(avenrun[2], EXP_15, active, n);
2472 calc_load_update += n * LOAD_FREQ;
2476 * Flip the idle index...
2478 * Make sure we first write the new time then flip the index, so that
2479 * calc_load_write_idx() will see the new time when it reads the new
2480 * index, this avoids a double flip messing things up.
2485 #else /* !CONFIG_NO_HZ */
2487 static inline long calc_load_fold_idle(void) { return 0; }
2488 static inline void calc_global_nohz(void) { }
2490 #endif /* CONFIG_NO_HZ */
2493 * calc_load - update the avenrun load estimates 10 ticks after the
2494 * CPUs have updated calc_load_tasks.
2496 void calc_global_load(unsigned long ticks)
2500 if (time_before(jiffies, calc_load_update + 10))
2504 * Fold the 'old' idle-delta to include all NO_HZ cpus.
2506 delta = calc_load_fold_idle();
2508 atomic_long_add(delta, &calc_load_tasks);
2510 active = atomic_long_read(&calc_load_tasks);
2511 active = active > 0 ? active * FIXED_1 : 0;
2513 avenrun[0] = calc_load(avenrun[0], EXP_1, active);
2514 avenrun[1] = calc_load(avenrun[1], EXP_5, active);
2515 avenrun[2] = calc_load(avenrun[2], EXP_15, active);
2517 calc_load_update += LOAD_FREQ;
2520 * In case we idled for multiple LOAD_FREQ intervals, catch up in bulk.
2526 * Called from update_cpu_load() to periodically update this CPU's
2529 static void calc_load_account_active(struct rq *this_rq)
2533 if (time_before(jiffies, this_rq->calc_load_update))
2536 delta = calc_load_fold_active(this_rq);
2538 atomic_long_add(delta, &calc_load_tasks);
2540 this_rq->calc_load_update += LOAD_FREQ;
2544 * End of global load-average stuff
2548 * The exact cpuload at various idx values, calculated at every tick would be
2549 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
2551 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
2552 * on nth tick when cpu may be busy, then we have:
2553 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2554 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
2556 * decay_load_missed() below does efficient calculation of
2557 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2558 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
2560 * The calculation is approximated on a 128 point scale.
2561 * degrade_zero_ticks is the number of ticks after which load at any
2562 * particular idx is approximated to be zero.
2563 * degrade_factor is a precomputed table, a row for each load idx.
2564 * Each column corresponds to degradation factor for a power of two ticks,
2565 * based on 128 point scale.
2567 * row 2, col 3 (=12) says that the degradation at load idx 2 after
2568 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
2570 * With this power of 2 load factors, we can degrade the load n times
2571 * by looking at 1 bits in n and doing as many mult/shift instead of
2572 * n mult/shifts needed by the exact degradation.
2574 #define DEGRADE_SHIFT 7
2575 static const unsigned char
2576 degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128};
2577 static const unsigned char
2578 degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = {
2579 {0, 0, 0, 0, 0, 0, 0, 0},
2580 {64, 32, 8, 0, 0, 0, 0, 0},
2581 {96, 72, 40, 12, 1, 0, 0},
2582 {112, 98, 75, 43, 15, 1, 0},
2583 {120, 112, 98, 76, 45, 16, 2} };
2586 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
2587 * would be when CPU is idle and so we just decay the old load without
2588 * adding any new load.
2590 static unsigned long
2591 decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
2595 if (!missed_updates)
2598 if (missed_updates >= degrade_zero_ticks[idx])
2602 return load >> missed_updates;
2604 while (missed_updates) {
2605 if (missed_updates % 2)
2606 load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT;
2608 missed_updates >>= 1;
2615 * Update rq->cpu_load[] statistics. This function is usually called every
2616 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
2617 * every tick. We fix it up based on jiffies.
2619 static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
2620 unsigned long pending_updates)
2624 this_rq->nr_load_updates++;
2626 /* Update our load: */
2627 this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
2628 for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2629 unsigned long old_load, new_load;
2631 /* scale is effectively 1 << i now, and >> i divides by scale */
2633 old_load = this_rq->cpu_load[i];
2634 old_load = decay_load_missed(old_load, pending_updates - 1, i);
2635 new_load = this_load;
2637 * Round up the averaging division if load is increasing. This
2638 * prevents us from getting stuck on 9 if the load is 10, for
2641 if (new_load > old_load)
2642 new_load += scale - 1;
2644 this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
2647 sched_avg_update(this_rq);
2652 * There is no sane way to deal with nohz on smp when using jiffies because the
2653 * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading
2654 * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}.
2656 * Therefore we cannot use the delta approach from the regular tick since that
2657 * would seriously skew the load calculation. However we'll make do for those
2658 * updates happening while idle (nohz_idle_balance) or coming out of idle
2659 * (tick_nohz_idle_exit).
2661 * This means we might still be one tick off for nohz periods.
2665 * Called from nohz_idle_balance() to update the load ratings before doing the
2668 void update_idle_cpu_load(struct rq *this_rq)
2670 unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
2671 unsigned long load = this_rq->load.weight;
2672 unsigned long pending_updates;
2675 * bail if there's load or we're actually up-to-date.
2677 if (load || curr_jiffies == this_rq->last_load_update_tick)
2680 pending_updates = curr_jiffies - this_rq->last_load_update_tick;
2681 this_rq->last_load_update_tick = curr_jiffies;
2683 __update_cpu_load(this_rq, load, pending_updates);
2687 * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed.
2689 void update_cpu_load_nohz(void)
2691 struct rq *this_rq = this_rq();
2692 unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
2693 unsigned long pending_updates;
2695 if (curr_jiffies == this_rq->last_load_update_tick)
2698 raw_spin_lock(&this_rq->lock);
2699 pending_updates = curr_jiffies - this_rq->last_load_update_tick;
2700 if (pending_updates) {
2701 this_rq->last_load_update_tick = curr_jiffies;
2703 * We were idle, this means load 0, the current load might be
2704 * !0 due to remote wakeups and the sort.
2706 __update_cpu_load(this_rq, 0, pending_updates);
2708 raw_spin_unlock(&this_rq->lock);
2710 #endif /* CONFIG_NO_HZ */
2713 * Called from scheduler_tick()
2715 static void update_cpu_load_active(struct rq *this_rq)
2718 * See the mess around update_idle_cpu_load() / update_cpu_load_nohz().
2720 this_rq->last_load_update_tick = jiffies;
2721 __update_cpu_load(this_rq, this_rq->load.weight, 1);
2723 calc_load_account_active(this_rq);
2729 * sched_exec - execve() is a valuable balancing opportunity, because at
2730 * this point the task has the smallest effective memory and cache footprint.
2732 void sched_exec(void)
2734 struct task_struct *p = current;
2735 unsigned long flags;
2738 raw_spin_lock_irqsave(&p->pi_lock, flags);
2739 dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0);
2740 if (dest_cpu == smp_processor_id())
2743 if (likely(cpu_active(dest_cpu))) {
2744 struct migration_arg arg = { p, dest_cpu };
2746 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2747 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
2751 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2756 DEFINE_PER_CPU(struct kernel_stat, kstat);
2757 DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
2759 EXPORT_PER_CPU_SYMBOL(kstat);
2760 EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
2763 * Return any ns on the sched_clock that have not yet been accounted in
2764 * @p in case that task is currently running.
2766 * Called with task_rq_lock() held on @rq.
2768 static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
2772 if (task_current(rq, p)) {
2773 update_rq_clock(rq);
2774 ns = rq->clock_task - p->se.exec_start;
2782 unsigned long long task_delta_exec(struct task_struct *p)
2784 unsigned long flags;
2788 rq = task_rq_lock(p, &flags);
2789 ns = do_task_delta_exec(p, rq);
2790 task_rq_unlock(rq, p, &flags);
2796 * Return accounted runtime for the task.
2797 * In case the task is currently running, return the runtime plus current's
2798 * pending runtime that have not been accounted yet.
2800 unsigned long long task_sched_runtime(struct task_struct *p)
2802 unsigned long flags;
2806 rq = task_rq_lock(p, &flags);
2807 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
2808 task_rq_unlock(rq, p, &flags);
2813 #ifdef CONFIG_CGROUP_CPUACCT
2814 struct cgroup_subsys cpuacct_subsys;
2815 struct cpuacct root_cpuacct;
2818 static inline void task_group_account_field(struct task_struct *p, int index,
2821 #ifdef CONFIG_CGROUP_CPUACCT
2822 struct kernel_cpustat *kcpustat;
2826 * Since all updates are sure to touch the root cgroup, we
2827 * get ourselves ahead and touch it first. If the root cgroup
2828 * is the only cgroup, then nothing else should be necessary.
2831 __get_cpu_var(kernel_cpustat).cpustat[index] += tmp;
2833 #ifdef CONFIG_CGROUP_CPUACCT
2834 if (unlikely(!cpuacct_subsys.active))
2839 while (ca && (ca != &root_cpuacct)) {
2840 kcpustat = this_cpu_ptr(ca->cpustat);
2841 kcpustat->cpustat[index] += tmp;
2850 * Account user cpu time to a process.
2851 * @p: the process that the cpu time gets accounted to
2852 * @cputime: the cpu time spent in user space since the last update
2853 * @cputime_scaled: cputime scaled by cpu frequency
2855 void account_user_time(struct task_struct *p, cputime_t cputime,
2856 cputime_t cputime_scaled)
2860 /* Add user time to process. */
2861 p->utime += cputime;
2862 p->utimescaled += cputime_scaled;
2863 account_group_user_time(p, cputime);
2865 index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
2867 /* Add user time to cpustat. */
2868 task_group_account_field(p, index, (__force u64) cputime);
2870 /* Account for user time used */
2871 acct_update_integrals(p);
2875 * Account guest cpu time to a process.
2876 * @p: the process that the cpu time gets accounted to
2877 * @cputime: the cpu time spent in virtual machine since the last update
2878 * @cputime_scaled: cputime scaled by cpu frequency
2880 static void account_guest_time(struct task_struct *p, cputime_t cputime,
2881 cputime_t cputime_scaled)
2883 u64 *cpustat = kcpustat_this_cpu->cpustat;
2885 /* Add guest time to process. */
2886 p->utime += cputime;
2887 p->utimescaled += cputime_scaled;
2888 account_group_user_time(p, cputime);
2889 p->gtime += cputime;
2891 /* Add guest time to cpustat. */
2892 if (TASK_NICE(p) > 0) {
2893 cpustat[CPUTIME_NICE] += (__force u64) cputime;
2894 cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;
2896 cpustat[CPUTIME_USER] += (__force u64) cputime;
2897 cpustat[CPUTIME_GUEST] += (__force u64) cputime;
2902 * Account system cpu time to a process and desired cpustat field
2903 * @p: the process that the cpu time gets accounted to
2904 * @cputime: the cpu time spent in kernel space since the last update
2905 * @cputime_scaled: cputime scaled by cpu frequency
2906 * @target_cputime64: pointer to cpustat field that has to be updated
2909 void __account_system_time(struct task_struct *p, cputime_t cputime,
2910 cputime_t cputime_scaled, int index)
2912 /* Add system time to process. */
2913 p->stime += cputime;
2914 p->stimescaled += cputime_scaled;
2915 account_group_system_time(p, cputime);
2917 /* Add system time to cpustat. */
2918 task_group_account_field(p, index, (__force u64) cputime);
2920 /* Account for system time used */
2921 acct_update_integrals(p);
2925 * Account system cpu time to a process.
2926 * @p: the process that the cpu time gets accounted to
2927 * @hardirq_offset: the offset to subtract from hardirq_count()
2928 * @cputime: the cpu time spent in kernel space since the last update
2929 * @cputime_scaled: cputime scaled by cpu frequency
2931 void account_system_time(struct task_struct *p, int hardirq_offset,
2932 cputime_t cputime, cputime_t cputime_scaled)
2936 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
2937 account_guest_time(p, cputime, cputime_scaled);
2941 if (hardirq_count() - hardirq_offset)
2942 index = CPUTIME_IRQ;
2943 else if (in_serving_softirq())
2944 index = CPUTIME_SOFTIRQ;
2946 index = CPUTIME_SYSTEM;
2948 __account_system_time(p, cputime, cputime_scaled, index);
2952 * Account for involuntary wait time.
2953 * @cputime: the cpu time spent in involuntary wait
2955 void account_steal_time(cputime_t cputime)
2957 u64 *cpustat = kcpustat_this_cpu->cpustat;
2959 cpustat[CPUTIME_STEAL] += (__force u64) cputime;
2963 * Account for idle time.
2964 * @cputime: the cpu time spent in idle wait
2966 void account_idle_time(cputime_t cputime)
2968 u64 *cpustat = kcpustat_this_cpu->cpustat;
2969 struct rq *rq = this_rq();
2971 if (atomic_read(&rq->nr_iowait) > 0)
2972 cpustat[CPUTIME_IOWAIT] += (__force u64) cputime;
2974 cpustat[CPUTIME_IDLE] += (__force u64) cputime;
2977 static __always_inline bool steal_account_process_tick(void)
2979 #ifdef CONFIG_PARAVIRT
2980 if (static_key_false(¶virt_steal_enabled)) {
2983 steal = paravirt_steal_clock(smp_processor_id());
2984 steal -= this_rq()->prev_steal_time;
2986 st = steal_ticks(steal);
2987 this_rq()->prev_steal_time += st * TICK_NSEC;
2989 account_steal_time(st);
2996 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
2998 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
3000 * Account a tick to a process and cpustat
3001 * @p: the process that the cpu time gets accounted to
3002 * @user_tick: is the tick from userspace
3003 * @rq: the pointer to rq
3005 * Tick demultiplexing follows the order
3006 * - pending hardirq update
3007 * - pending softirq update
3011 * - check for guest_time
3012 * - else account as system_time
3014 * Check for hardirq is done both for system and user time as there is
3015 * no timer going off while we are on hardirq and hence we may never get an
3016 * opportunity to update it solely in system time.
3017 * p->stime and friends are only updated on system time and not on irq
3018 * softirq as those do not count in task exec_runtime any more.
3020 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
3023 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
3024 u64 *cpustat = kcpustat_this_cpu->cpustat;
3026 if (steal_account_process_tick())
3029 if (irqtime_account_hi_update()) {
3030 cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
3031 } else if (irqtime_account_si_update()) {
3032 cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
3033 } else if (this_cpu_ksoftirqd() == p) {
3035 * ksoftirqd time do not get accounted in cpu_softirq_time.
3036 * So, we have to handle it separately here.
3037 * Also, p->stime needs to be updated for ksoftirqd.
3039 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
3041 } else if (user_tick) {
3042 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
3043 } else if (p == rq->idle) {
3044 account_idle_time(cputime_one_jiffy);
3045 } else if (p->flags & PF_VCPU) { /* System time or guest time */
3046 account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
3048 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
3053 static void irqtime_account_idle_ticks(int ticks)
3056 struct rq *rq = this_rq();
3058 for (i = 0; i < ticks; i++)
3059 irqtime_account_process_tick(current, 0, rq);
3061 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
3062 static void irqtime_account_idle_ticks(int ticks) {}
3063 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
3065 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
3068 * Account a single tick of cpu time.
3069 * @p: the process that the cpu time gets accounted to
3070 * @user_tick: indicates if the tick is a user or a system tick
3072 void account_process_tick(struct task_struct *p, int user_tick)
3074 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
3075 struct rq *rq = this_rq();
3077 if (sched_clock_irqtime) {
3078 irqtime_account_process_tick(p, user_tick, rq);
3082 if (steal_account_process_tick())
3086 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
3087 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
3088 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
3091 account_idle_time(cputime_one_jiffy);
3095 * Account multiple ticks of steal time.
3096 * @p: the process from which the cpu time has been stolen
3097 * @ticks: number of stolen ticks
3099 void account_steal_ticks(unsigned long ticks)
3101 account_steal_time(jiffies_to_cputime(ticks));
3105 * Account multiple ticks of idle time.
3106 * @ticks: number of stolen ticks
3108 void account_idle_ticks(unsigned long ticks)
3111 if (sched_clock_irqtime) {
3112 irqtime_account_idle_ticks(ticks);
3116 account_idle_time(jiffies_to_cputime(ticks));
3122 * Use precise platform statistics if available:
3124 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
3125 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3131 void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3133 struct task_cputime cputime;
3135 thread_group_cputime(p, &cputime);
3137 *ut = cputime.utime;
3138 *st = cputime.stime;
3142 #ifndef nsecs_to_cputime
3143 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
3146 void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3148 cputime_t rtime, utime = p->utime, total = utime + p->stime;
3151 * Use CFS's precise accounting:
3153 rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
3156 u64 temp = (__force u64) rtime;
3158 temp *= (__force u64) utime;
3159 do_div(temp, (__force u32) total);
3160 utime = (__force cputime_t) temp;
3165 * Compare with previous values, to keep monotonicity:
3167 p->prev_utime = max(p->prev_utime, utime);
3168 p->prev_stime = max(p->prev_stime, rtime - p->prev_utime);
3170 *ut = p->prev_utime;
3171 *st = p->prev_stime;
3175 * Must be called with siglock held.
3177 void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
3179 struct signal_struct *sig = p->signal;
3180 struct task_cputime cputime;
3181 cputime_t rtime, utime, total;
3183 thread_group_cputime(p, &cputime);
3185 total = cputime.utime + cputime.stime;
3186 rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
3189 u64 temp = (__force u64) rtime;
3191 temp *= (__force u64) cputime.utime;
3192 do_div(temp, (__force u32) total);
3193 utime = (__force cputime_t) temp;
3197 sig->prev_utime = max(sig->prev_utime, utime);
3198 sig->prev_stime = max(sig->prev_stime, rtime - sig->prev_utime);
3200 *ut = sig->prev_utime;
3201 *st = sig->prev_stime;
3206 * This function gets called by the timer code, with HZ frequency.
3207 * We call it with interrupts disabled.
3209 void scheduler_tick(void)
3211 int cpu = smp_processor_id();
3212 struct rq *rq = cpu_rq(cpu);
3213 struct task_struct *curr = rq->curr;
3217 raw_spin_lock(&rq->lock);
3218 update_rq_clock(rq);
3219 update_cpu_load_active(rq);
3220 curr->sched_class->task_tick(rq, curr, 0);
3221 raw_spin_unlock(&rq->lock);
3223 perf_event_task_tick();
3226 rq->idle_balance = idle_cpu(cpu);
3227 trigger_load_balance(rq, cpu);
3231 notrace unsigned long get_parent_ip(unsigned long addr)
3233 if (in_lock_functions(addr)) {
3234 addr = CALLER_ADDR2;
3235 if (in_lock_functions(addr))
3236 addr = CALLER_ADDR3;
3241 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3242 defined(CONFIG_PREEMPT_TRACER))
3244 void __kprobes add_preempt_count(int val)
3246 #ifdef CONFIG_DEBUG_PREEMPT
3250 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3253 preempt_count() += val;
3254 #ifdef CONFIG_DEBUG_PREEMPT
3256 * Spinlock count overflowing soon?
3258 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
3261 if (preempt_count() == val)
3262 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3264 EXPORT_SYMBOL(add_preempt_count);
3266 void __kprobes sub_preempt_count(int val)
3268 #ifdef CONFIG_DEBUG_PREEMPT
3272 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3275 * Is the spinlock portion underflowing?
3277 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
3278 !(preempt_count() & PREEMPT_MASK)))
3282 if (preempt_count() == val)
3283 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
3284 preempt_count() -= val;
3286 EXPORT_SYMBOL(sub_preempt_count);
3291 * Print scheduling while atomic bug:
3293 static noinline void __schedule_bug(struct task_struct *prev)
3295 if (oops_in_progress)
3298 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
3299 prev->comm, prev->pid, preempt_count());
3301 debug_show_held_locks(prev);
3303 if (irqs_disabled())
3304 print_irqtrace_events(prev);
3306 add_taint(TAINT_WARN);
3310 * Various schedule()-time debugging checks and statistics:
3312 static inline void schedule_debug(struct task_struct *prev)
3315 * Test if we are atomic. Since do_exit() needs to call into
3316 * schedule() atomically, we ignore that path for now.
3317 * Otherwise, whine if we are scheduling when we should not be.
3319 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
3320 __schedule_bug(prev);
3323 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
3325 schedstat_inc(this_rq(), sched_count);
3328 static void put_prev_task(struct rq *rq, struct task_struct *prev)
3330 if (prev->on_rq || rq->skip_clock_update < 0)
3331 update_rq_clock(rq);
3332 prev->sched_class->put_prev_task(rq, prev);
3336 * Pick up the highest-prio task:
3338 static inline struct task_struct *
3339 pick_next_task(struct rq *rq)
3341 const struct sched_class *class;
3342 struct task_struct *p;
3345 * Optimization: we know that if all tasks are in
3346 * the fair class we can call that function directly:
3348 if (likely(rq->nr_running == rq->cfs.h_nr_running)) {
3349 p = fair_sched_class.pick_next_task(rq);
3354 for_each_class(class) {
3355 p = class->pick_next_task(rq);
3360 BUG(); /* the idle class will always have a runnable task */
3364 * __schedule() is the main scheduler function.
3366 static void __sched __schedule(void)
3368 struct task_struct *prev, *next;
3369 unsigned long *switch_count;
3375 cpu = smp_processor_id();
3377 rcu_note_context_switch(cpu);
3380 schedule_debug(prev);
3382 if (sched_feat(HRTICK))
3385 raw_spin_lock_irq(&rq->lock);
3387 switch_count = &prev->nivcsw;
3388 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
3389 if (unlikely(signal_pending_state(prev->state, prev))) {
3390 prev->state = TASK_RUNNING;
3392 deactivate_task(rq, prev, DEQUEUE_SLEEP);
3396 * If a worker went to sleep, notify and ask workqueue
3397 * whether it wants to wake up a task to maintain
3400 if (prev->flags & PF_WQ_WORKER) {
3401 struct task_struct *to_wakeup;
3403 to_wakeup = wq_worker_sleeping(prev, cpu);
3405 try_to_wake_up_local(to_wakeup);
3408 switch_count = &prev->nvcsw;
3411 pre_schedule(rq, prev);
3413 if (unlikely(!rq->nr_running))
3414 idle_balance(cpu, rq);
3416 put_prev_task(rq, prev);
3417 next = pick_next_task(rq);
3418 clear_tsk_need_resched(prev);
3419 rq->skip_clock_update = 0;
3421 if (likely(prev != next)) {
3426 context_switch(rq, prev, next); /* unlocks the rq */
3428 * The context switch have flipped the stack from under us
3429 * and restored the local variables which were saved when
3430 * this task called schedule() in the past. prev == current
3431 * is still correct, but it can be moved to another cpu/rq.
3433 cpu = smp_processor_id();
3436 raw_spin_unlock_irq(&rq->lock);
3440 sched_preempt_enable_no_resched();
3445 static inline void sched_submit_work(struct task_struct *tsk)
3447 if (!tsk->state || tsk_is_pi_blocked(tsk))
3450 * If we are going to sleep and we have plugged IO queued,
3451 * make sure to submit it to avoid deadlocks.
3453 if (blk_needs_flush_plug(tsk))
3454 blk_schedule_flush_plug(tsk);
3457 asmlinkage void __sched schedule(void)
3459 struct task_struct *tsk = current;
3461 sched_submit_work(tsk);
3464 EXPORT_SYMBOL(schedule);
3467 * schedule_preempt_disabled - called with preemption disabled
3469 * Returns with preemption disabled. Note: preempt_count must be 1
3471 void __sched schedule_preempt_disabled(void)
3473 sched_preempt_enable_no_resched();
3478 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3480 static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
3482 if (lock->owner != owner)
3486 * Ensure we emit the owner->on_cpu, dereference _after_ checking
3487 * lock->owner still matches owner, if that fails, owner might
3488 * point to free()d memory, if it still matches, the rcu_read_lock()
3489 * ensures the memory stays valid.
3493 return owner->on_cpu;
3497 * Look out! "owner" is an entirely speculative pointer
3498 * access and not reliable.
3500 int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
3502 if (!sched_feat(OWNER_SPIN))
3506 while (owner_running(lock, owner)) {
3510 arch_mutex_cpu_relax();
3515 * We break out the loop above on need_resched() and when the
3516 * owner changed, which is a sign for heavy contention. Return
3517 * success only when lock->owner is NULL.
3519 return lock->owner == NULL;
3523 #ifdef CONFIG_PREEMPT
3525 * this is the entry point to schedule() from in-kernel preemption
3526 * off of preempt_enable. Kernel preemptions off return from interrupt
3527 * occur there and call schedule directly.
3529 asmlinkage void __sched notrace preempt_schedule(void)
3531 struct thread_info *ti = current_thread_info();
3534 * If there is a non-zero preempt_count or interrupts are disabled,
3535 * we do not want to preempt the current task. Just return..
3537 if (likely(ti->preempt_count || irqs_disabled()))
3541 add_preempt_count_notrace(PREEMPT_ACTIVE);
3543 sub_preempt_count_notrace(PREEMPT_ACTIVE);
3546 * Check again in case we missed a preemption opportunity
3547 * between schedule and now.
3550 } while (need_resched());
3552 EXPORT_SYMBOL(preempt_schedule);
3555 * this is the entry point to schedule() from kernel preemption
3556 * off of irq context.
3557 * Note, that this is called and return with irqs disabled. This will
3558 * protect us against recursive calling from irq.
3560 asmlinkage void __sched preempt_schedule_irq(void)
3562 struct thread_info *ti = current_thread_info();
3564 /* Catch callers which need to be fixed */
3565 BUG_ON(ti->preempt_count || !irqs_disabled());
3568 add_preempt_count(PREEMPT_ACTIVE);
3571 local_irq_disable();
3572 sub_preempt_count(PREEMPT_ACTIVE);
3575 * Check again in case we missed a preemption opportunity
3576 * between schedule and now.
3579 } while (need_resched());
3582 #endif /* CONFIG_PREEMPT */
3584 int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
3587 return try_to_wake_up(curr->private, mode, wake_flags);
3589 EXPORT_SYMBOL(default_wake_function);
3592 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3593 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3594 * number) then we wake all the non-exclusive tasks and one exclusive task.
3596 * There are circumstances in which we can try to wake a task which has already
3597 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3598 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3600 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
3601 int nr_exclusive, int wake_flags, void *key)
3603 wait_queue_t *curr, *next;
3605 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
3606 unsigned flags = curr->flags;
3608 if (curr->func(curr, mode, wake_flags, key) &&
3609 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
3615 * __wake_up - wake up threads blocked on a waitqueue.
3617 * @mode: which threads
3618 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3619 * @key: is directly passed to the wakeup function
3621 * It may be assumed that this function implies a write memory barrier before
3622 * changing the task state if and only if any tasks are woken up.
3624 void __wake_up(wait_queue_head_t *q, unsigned int mode,
3625 int nr_exclusive, void *key)
3627 unsigned long flags;
3629 spin_lock_irqsave(&q->lock, flags);
3630 __wake_up_common(q, mode, nr_exclusive, 0, key);
3631 spin_unlock_irqrestore(&q->lock, flags);
3633 EXPORT_SYMBOL(__wake_up);
3636 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3638 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr)
3640 __wake_up_common(q, mode, nr, 0, NULL);
3642 EXPORT_SYMBOL_GPL(__wake_up_locked);
3644 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
3646 __wake_up_common(q, mode, 1, 0, key);
3648 EXPORT_SYMBOL_GPL(__wake_up_locked_key);
3651 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
3653 * @mode: which threads
3654 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3655 * @key: opaque value to be passed to wakeup targets
3657 * The sync wakeup differs that the waker knows that it will schedule
3658 * away soon, so while the target thread will be woken up, it will not
3659 * be migrated to another CPU - ie. the two threads are 'synchronized'
3660 * with each other. This can prevent needless bouncing between CPUs.
3662 * On UP it can prevent extra preemption.
3664 * It may be assumed that this function implies a write memory barrier before
3665 * changing the task state if and only if any tasks are woken up.
3667 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
3668 int nr_exclusive, void *key)
3670 unsigned long flags;
3671 int wake_flags = WF_SYNC;
3676 if (unlikely(!nr_exclusive))
3679 spin_lock_irqsave(&q->lock, flags);
3680 __wake_up_common(q, mode, nr_exclusive, wake_flags, key);
3681 spin_unlock_irqrestore(&q->lock, flags);
3683 EXPORT_SYMBOL_GPL(__wake_up_sync_key);
3686 * __wake_up_sync - see __wake_up_sync_key()
3688 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
3690 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
3692 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
3695 * complete: - signals a single thread waiting on this completion
3696 * @x: holds the state of this particular completion
3698 * This will wake up a single thread waiting on this completion. Threads will be
3699 * awakened in the same order in which they were queued.
3701 * See also complete_all(), wait_for_completion() and related routines.
3703 * It may be assumed that this function implies a write memory barrier before
3704 * changing the task state if and only if any tasks are woken up.
3706 void complete(struct completion *x)
3708 unsigned long flags;
3710 spin_lock_irqsave(&x->wait.lock, flags);
3712 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
3713 spin_unlock_irqrestore(&x->wait.lock, flags);
3715 EXPORT_SYMBOL(complete);
3718 * complete_all: - signals all threads waiting on this completion
3719 * @x: holds the state of this particular completion
3721 * This will wake up all threads waiting on this particular completion event.
3723 * It may be assumed that this function implies a write memory barrier before
3724 * changing the task state if and only if any tasks are woken up.
3726 void complete_all(struct completion *x)
3728 unsigned long flags;
3730 spin_lock_irqsave(&x->wait.lock, flags);
3731 x->done += UINT_MAX/2;
3732 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
3733 spin_unlock_irqrestore(&x->wait.lock, flags);
3735 EXPORT_SYMBOL(complete_all);
3737 static inline long __sched
3738 do_wait_for_common(struct completion *x, long timeout, int state)
3741 DECLARE_WAITQUEUE(wait, current);
3743 __add_wait_queue_tail_exclusive(&x->wait, &wait);
3745 if (signal_pending_state(state, current)) {
3746 timeout = -ERESTARTSYS;
3749 __set_current_state(state);
3750 spin_unlock_irq(&x->wait.lock);
3751 timeout = schedule_timeout(timeout);
3752 spin_lock_irq(&x->wait.lock);
3753 } while (!x->done && timeout);
3754 __remove_wait_queue(&x->wait, &wait);
3759 return timeout ?: 1;
3763 wait_for_common(struct completion *x, long timeout, int state)
3767 spin_lock_irq(&x->wait.lock);
3768 timeout = do_wait_for_common(x, timeout, state);
3769 spin_unlock_irq(&x->wait.lock);
3774 * wait_for_completion: - waits for completion of a task
3775 * @x: holds the state of this particular completion
3777 * This waits to be signaled for completion of a specific task. It is NOT
3778 * interruptible and there is no timeout.
3780 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
3781 * and interrupt capability. Also see complete().
3783 void __sched wait_for_completion(struct completion *x)
3785 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
3787 EXPORT_SYMBOL(wait_for_completion);
3790 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
3791 * @x: holds the state of this particular completion
3792 * @timeout: timeout value in jiffies
3794 * This waits for either a completion of a specific task to be signaled or for a
3795 * specified timeout to expire. The timeout is in jiffies. It is not
3798 * The return value is 0 if timed out, and positive (at least 1, or number of
3799 * jiffies left till timeout) if completed.
3801 unsigned long __sched
3802 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
3804 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
3806 EXPORT_SYMBOL(wait_for_completion_timeout);
3809 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
3810 * @x: holds the state of this particular completion
3812 * This waits for completion of a specific task to be signaled. It is
3815 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3817 int __sched wait_for_completion_interruptible(struct completion *x)
3819 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
3820 if (t == -ERESTARTSYS)
3824 EXPORT_SYMBOL(wait_for_completion_interruptible);
3827 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
3828 * @x: holds the state of this particular completion
3829 * @timeout: timeout value in jiffies
3831 * This waits for either a completion of a specific task to be signaled or for a
3832 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
3834 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3835 * positive (at least 1, or number of jiffies left till timeout) if completed.
3838 wait_for_completion_interruptible_timeout(struct completion *x,
3839 unsigned long timeout)
3841 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
3843 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
3846 * wait_for_completion_killable: - waits for completion of a task (killable)
3847 * @x: holds the state of this particular completion
3849 * This waits to be signaled for completion of a specific task. It can be
3850 * interrupted by a kill signal.
3852 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3854 int __sched wait_for_completion_killable(struct completion *x)
3856 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
3857 if (t == -ERESTARTSYS)
3861 EXPORT_SYMBOL(wait_for_completion_killable);
3864 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
3865 * @x: holds the state of this particular completion
3866 * @timeout: timeout value in jiffies
3868 * This waits for either a completion of a specific task to be
3869 * signaled or for a specified timeout to expire. It can be
3870 * interrupted by a kill signal. The timeout is in jiffies.
3872 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3873 * positive (at least 1, or number of jiffies left till timeout) if completed.
3876 wait_for_completion_killable_timeout(struct completion *x,
3877 unsigned long timeout)
3879 return wait_for_common(x, timeout, TASK_KILLABLE);
3881 EXPORT_SYMBOL(wait_for_completion_killable_timeout);
3884 * try_wait_for_completion - try to decrement a completion without blocking
3885 * @x: completion structure
3887 * Returns: 0 if a decrement cannot be done without blocking
3888 * 1 if a decrement succeeded.
3890 * If a completion is being used as a counting completion,
3891 * attempt to decrement the counter without blocking. This
3892 * enables us to avoid waiting if the resource the completion
3893 * is protecting is not available.
3895 bool try_wait_for_completion(struct completion *x)
3897 unsigned long flags;
3900 spin_lock_irqsave(&x->wait.lock, flags);
3905 spin_unlock_irqrestore(&x->wait.lock, flags);
3908 EXPORT_SYMBOL(try_wait_for_completion);
3911 * completion_done - Test to see if a completion has any waiters
3912 * @x: completion structure
3914 * Returns: 0 if there are waiters (wait_for_completion() in progress)
3915 * 1 if there are no waiters.
3918 bool completion_done(struct completion *x)
3920 unsigned long flags;
3923 spin_lock_irqsave(&x->wait.lock, flags);
3926 spin_unlock_irqrestore(&x->wait.lock, flags);
3929 EXPORT_SYMBOL(completion_done);
3932 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
3934 unsigned long flags;
3937 init_waitqueue_entry(&wait, current);
3939 __set_current_state(state);
3941 spin_lock_irqsave(&q->lock, flags);
3942 __add_wait_queue(q, &wait);
3943 spin_unlock(&q->lock);
3944 timeout = schedule_timeout(timeout);
3945 spin_lock_irq(&q->lock);
3946 __remove_wait_queue(q, &wait);
3947 spin_unlock_irqrestore(&q->lock, flags);
3952 void __sched interruptible_sleep_on(wait_queue_head_t *q)
3954 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
3956 EXPORT_SYMBOL(interruptible_sleep_on);
3959 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
3961 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
3963 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
3965 void __sched sleep_on(wait_queue_head_t *q)
3967 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
3969 EXPORT_SYMBOL(sleep_on);
3971 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
3973 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
3975 EXPORT_SYMBOL(sleep_on_timeout);
3977 #ifdef CONFIG_RT_MUTEXES
3980 * rt_mutex_setprio - set the current priority of a task
3982 * @prio: prio value (kernel-internal form)
3984 * This function changes the 'effective' priority of a task. It does
3985 * not touch ->normal_prio like __setscheduler().
3987 * Used by the rt_mutex code to implement priority inheritance logic.
3989 void rt_mutex_setprio(struct task_struct *p, int prio)
3991 int oldprio, on_rq, running;
3993 const struct sched_class *prev_class;
3995 BUG_ON(prio < 0 || prio > MAX_PRIO);
3997 rq = __task_rq_lock(p);
4000 * Idle task boosting is a nono in general. There is one
4001 * exception, when PREEMPT_RT and NOHZ is active:
4003 * The idle task calls get_next_timer_interrupt() and holds
4004 * the timer wheel base->lock on the CPU and another CPU wants
4005 * to access the timer (probably to cancel it). We can safely
4006 * ignore the boosting request, as the idle CPU runs this code
4007 * with interrupts disabled and will complete the lock
4008 * protected section without being interrupted. So there is no
4009 * real need to boost.
4011 if (unlikely(p == rq->idle)) {
4012 WARN_ON(p != rq->curr);
4013 WARN_ON(p->pi_blocked_on);
4017 trace_sched_pi_setprio(p, prio);
4019 prev_class = p->sched_class;
4021 running = task_current(rq, p);
4023 dequeue_task(rq, p, 0);
4025 p->sched_class->put_prev_task(rq, p);
4028 p->sched_class = &rt_sched_class;
4030 p->sched_class = &fair_sched_class;
4035 p->sched_class->set_curr_task(rq);
4037 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
4039 check_class_changed(rq, p, prev_class, oldprio);
4041 __task_rq_unlock(rq);
4044 void set_user_nice(struct task_struct *p, long nice)
4046 int old_prio, delta, on_rq;
4047 unsigned long flags;
4050 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
4053 * We have to be careful, if called from sys_setpriority(),
4054 * the task might be in the middle of scheduling on another CPU.
4056 rq = task_rq_lock(p, &flags);
4058 * The RT priorities are set via sched_setscheduler(), but we still
4059 * allow the 'normal' nice value to be set - but as expected
4060 * it wont have any effect on scheduling until the task is
4061 * SCHED_FIFO/SCHED_RR:
4063 if (task_has_rt_policy(p)) {
4064 p->static_prio = NICE_TO_PRIO(nice);
4069 dequeue_task(rq, p, 0);
4071 p->static_prio = NICE_TO_PRIO(nice);
4074 p->prio = effective_prio(p);
4075 delta = p->prio - old_prio;
4078 enqueue_task(rq, p, 0);
4080 * If the task increased its priority or is running and
4081 * lowered its priority, then reschedule its CPU:
4083 if (delta < 0 || (delta > 0 && task_running(rq, p)))
4084 resched_task(rq->curr);
4087 task_rq_unlock(rq, p, &flags);
4089 EXPORT_SYMBOL(set_user_nice);
4092 * can_nice - check if a task can reduce its nice value
4096 int can_nice(const struct task_struct *p, const int nice)
4098 /* convert nice value [19,-20] to rlimit style value [1,40] */
4099 int nice_rlim = 20 - nice;
4101 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
4102 capable(CAP_SYS_NICE));
4105 #ifdef __ARCH_WANT_SYS_NICE
4108 * sys_nice - change the priority of the current process.
4109 * @increment: priority increment
4111 * sys_setpriority is a more generic, but much slower function that
4112 * does similar things.
4114 SYSCALL_DEFINE1(nice, int, increment)
4119 * Setpriority might change our priority at the same moment.
4120 * We don't have to worry. Conceptually one call occurs first
4121 * and we have a single winner.
4123 if (increment < -40)
4128 nice = TASK_NICE(current) + increment;
4134 if (increment < 0 && !can_nice(current, nice))
4137 retval = security_task_setnice(current, nice);
4141 set_user_nice(current, nice);
4148 * task_prio - return the priority value of a given task.
4149 * @p: the task in question.
4151 * This is the priority value as seen by users in /proc.
4152 * RT tasks are offset by -200. Normal tasks are centered
4153 * around 0, value goes from -16 to +15.
4155 int task_prio(const struct task_struct *p)
4157 return p->prio - MAX_RT_PRIO;
4161 * task_nice - return the nice value of a given task.
4162 * @p: the task in question.
4164 int task_nice(const struct task_struct *p)
4166 return TASK_NICE(p);
4168 EXPORT_SYMBOL(task_nice);
4171 * idle_cpu - is a given cpu idle currently?
4172 * @cpu: the processor in question.
4174 int idle_cpu(int cpu)
4176 struct rq *rq = cpu_rq(cpu);
4178 if (rq->curr != rq->idle)
4185 if (!llist_empty(&rq->wake_list))
4193 * idle_task - return the idle task for a given cpu.
4194 * @cpu: the processor in question.
4196 struct task_struct *idle_task(int cpu)
4198 return cpu_rq(cpu)->idle;
4202 * find_process_by_pid - find a process with a matching PID value.
4203 * @pid: the pid in question.
4205 static struct task_struct *find_process_by_pid(pid_t pid)
4207 return pid ? find_task_by_vpid(pid) : current;
4210 /* Actually do priority change: must hold rq lock. */
4212 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
4215 p->rt_priority = prio;
4216 p->normal_prio = normal_prio(p);
4217 /* we are holding p->pi_lock already */
4218 p->prio = rt_mutex_getprio(p);
4219 if (rt_prio(p->prio))
4220 p->sched_class = &rt_sched_class;
4222 p->sched_class = &fair_sched_class;
4227 * check the target process has a UID that matches the current process's
4229 static bool check_same_owner(struct task_struct *p)
4231 const struct cred *cred = current_cred(), *pcred;
4235 pcred = __task_cred(p);
4236 match = (uid_eq(cred->euid, pcred->euid) ||
4237 uid_eq(cred->euid, pcred->uid));
4242 static int __sched_setscheduler(struct task_struct *p, int policy,
4243 const struct sched_param *param, bool user)
4245 int retval, oldprio, oldpolicy = -1, on_rq, running;
4246 unsigned long flags;
4247 const struct sched_class *prev_class;
4251 /* may grab non-irq protected spin_locks */
4252 BUG_ON(in_interrupt());
4254 /* double check policy once rq lock held */
4256 reset_on_fork = p->sched_reset_on_fork;
4257 policy = oldpolicy = p->policy;
4259 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
4260 policy &= ~SCHED_RESET_ON_FORK;
4262 if (policy != SCHED_FIFO && policy != SCHED_RR &&
4263 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
4264 policy != SCHED_IDLE)
4269 * Valid priorities for SCHED_FIFO and SCHED_RR are
4270 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4271 * SCHED_BATCH and SCHED_IDLE is 0.
4273 if (param->sched_priority < 0 ||
4274 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
4275 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
4277 if (rt_policy(policy) != (param->sched_priority != 0))
4281 * Allow unprivileged RT tasks to decrease priority:
4283 if (user && !capable(CAP_SYS_NICE)) {
4284 if (rt_policy(policy)) {
4285 unsigned long rlim_rtprio =
4286 task_rlimit(p, RLIMIT_RTPRIO);
4288 /* can't set/change the rt policy */
4289 if (policy != p->policy && !rlim_rtprio)
4292 /* can't increase priority */
4293 if (param->sched_priority > p->rt_priority &&
4294 param->sched_priority > rlim_rtprio)
4299 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4300 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4302 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
4303 if (!can_nice(p, TASK_NICE(p)))
4307 /* can't change other user's priorities */
4308 if (!check_same_owner(p))
4311 /* Normal users shall not reset the sched_reset_on_fork flag */
4312 if (p->sched_reset_on_fork && !reset_on_fork)
4317 retval = security_task_setscheduler(p);
4323 * make sure no PI-waiters arrive (or leave) while we are
4324 * changing the priority of the task:
4326 * To be able to change p->policy safely, the appropriate
4327 * runqueue lock must be held.
4329 rq = task_rq_lock(p, &flags);
4332 * Changing the policy of the stop threads its a very bad idea
4334 if (p == rq->stop) {
4335 task_rq_unlock(rq, p, &flags);
4340 * If not changing anything there's no need to proceed further:
4342 if (unlikely(policy == p->policy && (!rt_policy(policy) ||
4343 param->sched_priority == p->rt_priority))) {
4345 __task_rq_unlock(rq);
4346 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4350 #ifdef CONFIG_RT_GROUP_SCHED
4353 * Do not allow realtime tasks into groups that have no runtime
4356 if (rt_bandwidth_enabled() && rt_policy(policy) &&
4357 task_group(p)->rt_bandwidth.rt_runtime == 0 &&
4358 !task_group_is_autogroup(task_group(p))) {
4359 task_rq_unlock(rq, p, &flags);
4365 /* recheck policy now with rq lock held */
4366 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
4367 policy = oldpolicy = -1;
4368 task_rq_unlock(rq, p, &flags);
4372 running = task_current(rq, p);
4374 dequeue_task(rq, p, 0);
4376 p->sched_class->put_prev_task(rq, p);
4378 p->sched_reset_on_fork = reset_on_fork;
4381 prev_class = p->sched_class;
4382 __setscheduler(rq, p, policy, param->sched_priority);
4385 p->sched_class->set_curr_task(rq);
4387 enqueue_task(rq, p, 0);
4389 check_class_changed(rq, p, prev_class, oldprio);
4390 task_rq_unlock(rq, p, &flags);
4392 rt_mutex_adjust_pi(p);
4398 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4399 * @p: the task in question.
4400 * @policy: new policy.
4401 * @param: structure containing the new RT priority.
4403 * NOTE that the task may be already dead.
4405 int sched_setscheduler(struct task_struct *p, int policy,
4406 const struct sched_param *param)
4408 return __sched_setscheduler(p, policy, param, true);
4410 EXPORT_SYMBOL_GPL(sched_setscheduler);
4413 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4414 * @p: the task in question.
4415 * @policy: new policy.
4416 * @param: structure containing the new RT priority.
4418 * Just like sched_setscheduler, only don't bother checking if the
4419 * current context has permission. For example, this is needed in
4420 * stop_machine(): we create temporary high priority worker threads,
4421 * but our caller might not have that capability.
4423 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
4424 const struct sched_param *param)
4426 return __sched_setscheduler(p, policy, param, false);
4430 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
4432 struct sched_param lparam;
4433 struct task_struct *p;
4436 if (!param || pid < 0)
4438 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
4443 p = find_process_by_pid(pid);
4445 retval = sched_setscheduler(p, policy, &lparam);
4452 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4453 * @pid: the pid in question.
4454 * @policy: new policy.
4455 * @param: structure containing the new RT priority.
4457 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
4458 struct sched_param __user *, param)
4460 /* negative values for policy are not valid */
4464 return do_sched_setscheduler(pid, policy, param);
4468 * sys_sched_setparam - set/change the RT priority of a thread
4469 * @pid: the pid in question.
4470 * @param: structure containing the new RT priority.
4472 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
4474 return do_sched_setscheduler(pid, -1, param);
4478 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4479 * @pid: the pid in question.
4481 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
4483 struct task_struct *p;
4491 p = find_process_by_pid(pid);
4493 retval = security_task_getscheduler(p);
4496 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
4503 * sys_sched_getparam - get the RT priority of a thread
4504 * @pid: the pid in question.
4505 * @param: structure containing the RT priority.
4507 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
4509 struct sched_param lp;
4510 struct task_struct *p;
4513 if (!param || pid < 0)
4517 p = find_process_by_pid(pid);
4522 retval = security_task_getscheduler(p);
4526 lp.sched_priority = p->rt_priority;
4530 * This one might sleep, we cannot do it with a spinlock held ...
4532 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
4541 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
4543 cpumask_var_t cpus_allowed, new_mask;
4544 struct task_struct *p;
4550 p = find_process_by_pid(pid);
4557 /* Prevent p going away */
4561 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
4565 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
4567 goto out_free_cpus_allowed;
4570 if (!check_same_owner(p) && !ns_capable(task_user_ns(p), CAP_SYS_NICE))
4573 retval = security_task_setscheduler(p);
4577 cpuset_cpus_allowed(p, cpus_allowed);
4578 cpumask_and(new_mask, in_mask, cpus_allowed);
4580 retval = set_cpus_allowed_ptr(p, new_mask);
4583 cpuset_cpus_allowed(p, cpus_allowed);
4584 if (!cpumask_subset(new_mask, cpus_allowed)) {
4586 * We must have raced with a concurrent cpuset
4587 * update. Just reset the cpus_allowed to the
4588 * cpuset's cpus_allowed
4590 cpumask_copy(new_mask, cpus_allowed);
4595 free_cpumask_var(new_mask);
4596 out_free_cpus_allowed:
4597 free_cpumask_var(cpus_allowed);
4604 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
4605 struct cpumask *new_mask)
4607 if (len < cpumask_size())
4608 cpumask_clear(new_mask);
4609 else if (len > cpumask_size())
4610 len = cpumask_size();
4612 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
4616 * sys_sched_setaffinity - set the cpu affinity of a process
4617 * @pid: pid of the process
4618 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4619 * @user_mask_ptr: user-space pointer to the new cpu mask
4621 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
4622 unsigned long __user *, user_mask_ptr)
4624 cpumask_var_t new_mask;
4627 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
4630 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
4632 retval = sched_setaffinity(pid, new_mask);
4633 free_cpumask_var(new_mask);
4637 long sched_getaffinity(pid_t pid, struct cpumask *mask)
4639 struct task_struct *p;
4640 unsigned long flags;
4647 p = find_process_by_pid(pid);
4651 retval = security_task_getscheduler(p);
4655 raw_spin_lock_irqsave(&p->pi_lock, flags);
4656 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
4657 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4667 * sys_sched_getaffinity - get the cpu affinity of a process
4668 * @pid: pid of the process
4669 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4670 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4672 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
4673 unsigned long __user *, user_mask_ptr)
4678 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
4680 if (len & (sizeof(unsigned long)-1))
4683 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
4686 ret = sched_getaffinity(pid, mask);
4688 size_t retlen = min_t(size_t, len, cpumask_size());
4690 if (copy_to_user(user_mask_ptr, mask, retlen))
4695 free_cpumask_var(mask);
4701 * sys_sched_yield - yield the current processor to other threads.
4703 * This function yields the current CPU to other tasks. If there are no
4704 * other threads running on this CPU then this function will return.
4706 SYSCALL_DEFINE0(sched_yield)
4708 struct rq *rq = this_rq_lock();
4710 schedstat_inc(rq, yld_count);
4711 current->sched_class->yield_task(rq);
4714 * Since we are going to call schedule() anyway, there's
4715 * no need to preempt or enable interrupts:
4717 __release(rq->lock);
4718 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
4719 do_raw_spin_unlock(&rq->lock);
4720 sched_preempt_enable_no_resched();
4727 static inline int should_resched(void)
4729 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
4732 static void __cond_resched(void)
4734 add_preempt_count(PREEMPT_ACTIVE);
4736 sub_preempt_count(PREEMPT_ACTIVE);
4739 int __sched _cond_resched(void)
4741 if (should_resched()) {
4747 EXPORT_SYMBOL(_cond_resched);
4750 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4751 * call schedule, and on return reacquire the lock.
4753 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4754 * operations here to prevent schedule() from being called twice (once via
4755 * spin_unlock(), once by hand).
4757 int __cond_resched_lock(spinlock_t *lock)
4759 int resched = should_resched();
4762 lockdep_assert_held(lock);
4764 if (spin_needbreak(lock) || resched) {
4775 EXPORT_SYMBOL(__cond_resched_lock);
4777 int __sched __cond_resched_softirq(void)
4779 BUG_ON(!in_softirq());
4781 if (should_resched()) {
4789 EXPORT_SYMBOL(__cond_resched_softirq);
4792 * yield - yield the current processor to other threads.
4794 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4796 * The scheduler is at all times free to pick the calling task as the most
4797 * eligible task to run, if removing the yield() call from your code breaks
4798 * it, its already broken.
4800 * Typical broken usage is:
4805 * where one assumes that yield() will let 'the other' process run that will
4806 * make event true. If the current task is a SCHED_FIFO task that will never
4807 * happen. Never use yield() as a progress guarantee!!
4809 * If you want to use yield() to wait for something, use wait_event().
4810 * If you want to use yield() to be 'nice' for others, use cond_resched().
4811 * If you still want to use yield(), do not!
4813 void __sched yield(void)
4815 set_current_state(TASK_RUNNING);
4818 EXPORT_SYMBOL(yield);
4821 * yield_to - yield the current processor to another thread in
4822 * your thread group, or accelerate that thread toward the
4823 * processor it's on.
4825 * @preempt: whether task preemption is allowed or not
4827 * It's the caller's job to ensure that the target task struct
4828 * can't go away on us before we can do any checks.
4830 * Returns true if we indeed boosted the target task.
4832 bool __sched yield_to(struct task_struct *p, bool preempt)
4834 struct task_struct *curr = current;
4835 struct rq *rq, *p_rq;
4836 unsigned long flags;
4839 local_irq_save(flags);
4844 double_rq_lock(rq, p_rq);
4845 while (task_rq(p) != p_rq) {
4846 double_rq_unlock(rq, p_rq);
4850 if (!curr->sched_class->yield_to_task)
4853 if (curr->sched_class != p->sched_class)
4856 if (task_running(p_rq, p) || p->state)
4859 yielded = curr->sched_class->yield_to_task(rq, p, preempt);
4861 schedstat_inc(rq, yld_count);
4863 * Make p's CPU reschedule; pick_next_entity takes care of
4866 if (preempt && rq != p_rq)
4867 resched_task(p_rq->curr);
4870 * We might have set it in task_yield_fair(), but are
4871 * not going to schedule(), so don't want to skip
4874 rq->skip_clock_update = 0;
4878 double_rq_unlock(rq, p_rq);
4879 local_irq_restore(flags);
4886 EXPORT_SYMBOL_GPL(yield_to);
4889 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4890 * that process accounting knows that this is a task in IO wait state.
4892 void __sched io_schedule(void)
4894 struct rq *rq = raw_rq();
4896 delayacct_blkio_start();
4897 atomic_inc(&rq->nr_iowait);
4898 blk_flush_plug(current);
4899 current->in_iowait = 1;
4901 current->in_iowait = 0;
4902 atomic_dec(&rq->nr_iowait);
4903 delayacct_blkio_end();
4905 EXPORT_SYMBOL(io_schedule);
4907 long __sched io_schedule_timeout(long timeout)
4909 struct rq *rq = raw_rq();
4912 delayacct_blkio_start();
4913 atomic_inc(&rq->nr_iowait);
4914 blk_flush_plug(current);
4915 current->in_iowait = 1;
4916 ret = schedule_timeout(timeout);
4917 current->in_iowait = 0;
4918 atomic_dec(&rq->nr_iowait);
4919 delayacct_blkio_end();
4924 * sys_sched_get_priority_max - return maximum RT priority.
4925 * @policy: scheduling class.
4927 * this syscall returns the maximum rt_priority that can be used
4928 * by a given scheduling class.
4930 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
4937 ret = MAX_USER_RT_PRIO-1;
4949 * sys_sched_get_priority_min - return minimum RT priority.
4950 * @policy: scheduling class.
4952 * this syscall returns the minimum rt_priority that can be used
4953 * by a given scheduling class.
4955 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
4973 * sys_sched_rr_get_interval - return the default timeslice of a process.
4974 * @pid: pid of the process.
4975 * @interval: userspace pointer to the timeslice value.
4977 * this syscall writes the default timeslice value of a given process
4978 * into the user-space timespec buffer. A value of '0' means infinity.
4980 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
4981 struct timespec __user *, interval)
4983 struct task_struct *p;
4984 unsigned int time_slice;
4985 unsigned long flags;
4995 p = find_process_by_pid(pid);
4999 retval = security_task_getscheduler(p);
5003 rq = task_rq_lock(p, &flags);
5004 time_slice = p->sched_class->get_rr_interval(rq, p);
5005 task_rq_unlock(rq, p, &flags);
5008 jiffies_to_timespec(time_slice, &t);
5009 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
5017 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
5019 void sched_show_task(struct task_struct *p)
5021 unsigned long free = 0;
5024 state = p->state ? __ffs(p->state) + 1 : 0;
5025 printk(KERN_INFO "%-15.15s %c", p->comm,
5026 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
5027 #if BITS_PER_LONG == 32
5028 if (state == TASK_RUNNING)
5029 printk(KERN_CONT " running ");
5031 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
5033 if (state == TASK_RUNNING)
5034 printk(KERN_CONT " running task ");
5036 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
5038 #ifdef CONFIG_DEBUG_STACK_USAGE
5039 free = stack_not_used(p);
5041 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
5042 task_pid_nr(p), task_pid_nr(rcu_dereference(p->real_parent)),
5043 (unsigned long)task_thread_info(p)->flags);
5045 show_stack(p, NULL);
5048 void show_state_filter(unsigned long state_filter)
5050 struct task_struct *g, *p;
5052 #if BITS_PER_LONG == 32
5054 " task PC stack pid father\n");
5057 " task PC stack pid father\n");
5060 do_each_thread(g, p) {
5062 * reset the NMI-timeout, listing all files on a slow
5063 * console might take a lot of time:
5065 touch_nmi_watchdog();
5066 if (!state_filter || (p->state & state_filter))
5068 } while_each_thread(g, p);
5070 touch_all_softlockup_watchdogs();
5072 #ifdef CONFIG_SCHED_DEBUG
5073 sysrq_sched_debug_show();
5077 * Only show locks if all tasks are dumped:
5080 debug_show_all_locks();
5083 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
5085 idle->sched_class = &idle_sched_class;
5089 * init_idle - set up an idle thread for a given CPU
5090 * @idle: task in question
5091 * @cpu: cpu the idle task belongs to
5093 * NOTE: this function does not set the idle thread's NEED_RESCHED
5094 * flag, to make booting more robust.
5096 void __cpuinit init_idle(struct task_struct *idle, int cpu)
5098 struct rq *rq = cpu_rq(cpu);
5099 unsigned long flags;
5101 raw_spin_lock_irqsave(&rq->lock, flags);
5104 idle->state = TASK_RUNNING;
5105 idle->se.exec_start = sched_clock();
5107 do_set_cpus_allowed(idle, cpumask_of(cpu));
5109 * We're having a chicken and egg problem, even though we are
5110 * holding rq->lock, the cpu isn't yet set to this cpu so the
5111 * lockdep check in task_group() will fail.
5113 * Similar case to sched_fork(). / Alternatively we could
5114 * use task_rq_lock() here and obtain the other rq->lock.
5119 __set_task_cpu(idle, cpu);
5122 rq->curr = rq->idle = idle;
5123 #if defined(CONFIG_SMP)
5126 raw_spin_unlock_irqrestore(&rq->lock, flags);
5128 /* Set the preempt count _outside_ the spinlocks! */
5129 task_thread_info(idle)->preempt_count = 0;
5132 * The idle tasks have their own, simple scheduling class:
5134 idle->sched_class = &idle_sched_class;
5135 ftrace_graph_init_idle_task(idle, cpu);
5136 #if defined(CONFIG_SMP)
5137 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
5142 void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
5144 if (p->sched_class && p->sched_class->set_cpus_allowed)
5145 p->sched_class->set_cpus_allowed(p, new_mask);
5147 cpumask_copy(&p->cpus_allowed, new_mask);
5148 p->nr_cpus_allowed = cpumask_weight(new_mask);
5152 * This is how migration works:
5154 * 1) we invoke migration_cpu_stop() on the target CPU using
5156 * 2) stopper starts to run (implicitly forcing the migrated thread
5158 * 3) it checks whether the migrated task is still in the wrong runqueue.
5159 * 4) if it's in the wrong runqueue then the migration thread removes
5160 * it and puts it into the right queue.
5161 * 5) stopper completes and stop_one_cpu() returns and the migration
5166 * Change a given task's CPU affinity. Migrate the thread to a
5167 * proper CPU and schedule it away if the CPU it's executing on
5168 * is removed from the allowed bitmask.
5170 * NOTE: the caller must have a valid reference to the task, the
5171 * task must not exit() & deallocate itself prematurely. The
5172 * call is not atomic; no spinlocks may be held.
5174 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
5176 unsigned long flags;
5178 unsigned int dest_cpu;
5181 rq = task_rq_lock(p, &flags);
5183 if (cpumask_equal(&p->cpus_allowed, new_mask))
5186 if (!cpumask_intersects(new_mask, cpu_active_mask)) {
5191 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) {
5196 do_set_cpus_allowed(p, new_mask);
5198 /* Can the task run on the task's current CPU? If so, we're done */
5199 if (cpumask_test_cpu(task_cpu(p), new_mask))
5202 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
5204 struct migration_arg arg = { p, dest_cpu };
5205 /* Need help from migration thread: drop lock and wait. */
5206 task_rq_unlock(rq, p, &flags);
5207 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
5208 tlb_migrate_finish(p->mm);
5212 task_rq_unlock(rq, p, &flags);
5216 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
5219 * Move (not current) task off this cpu, onto dest cpu. We're doing
5220 * this because either it can't run here any more (set_cpus_allowed()
5221 * away from this CPU, or CPU going down), or because we're
5222 * attempting to rebalance this task on exec (sched_exec).
5224 * So we race with normal scheduler movements, but that's OK, as long
5225 * as the task is no longer on this CPU.
5227 * Returns non-zero if task was successfully migrated.
5229 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
5231 struct rq *rq_dest, *rq_src;
5234 if (unlikely(!cpu_active(dest_cpu)))
5237 rq_src = cpu_rq(src_cpu);
5238 rq_dest = cpu_rq(dest_cpu);
5240 raw_spin_lock(&p->pi_lock);
5241 double_rq_lock(rq_src, rq_dest);
5242 /* Already moved. */
5243 if (task_cpu(p) != src_cpu)
5245 /* Affinity changed (again). */
5246 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
5250 * If we're not on a rq, the next wake-up will ensure we're
5254 dequeue_task(rq_src, p, 0);
5255 set_task_cpu(p, dest_cpu);
5256 enqueue_task(rq_dest, p, 0);
5257 check_preempt_curr(rq_dest, p, 0);
5262 double_rq_unlock(rq_src, rq_dest);
5263 raw_spin_unlock(&p->pi_lock);
5268 * migration_cpu_stop - this will be executed by a highprio stopper thread
5269 * and performs thread migration by bumping thread off CPU then
5270 * 'pushing' onto another runqueue.
5272 static int migration_cpu_stop(void *data)
5274 struct migration_arg *arg = data;
5277 * The original target cpu might have gone down and we might
5278 * be on another cpu but it doesn't matter.
5280 local_irq_disable();
5281 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
5286 #ifdef CONFIG_HOTPLUG_CPU
5289 * Ensures that the idle task is using init_mm right before its cpu goes
5292 void idle_task_exit(void)
5294 struct mm_struct *mm = current->active_mm;
5296 BUG_ON(cpu_online(smp_processor_id()));
5299 switch_mm(mm, &init_mm, current);
5304 * While a dead CPU has no uninterruptible tasks queued at this point,
5305 * it might still have a nonzero ->nr_uninterruptible counter, because
5306 * for performance reasons the counter is not stricly tracking tasks to
5307 * their home CPUs. So we just add the counter to another CPU's counter,
5308 * to keep the global sum constant after CPU-down:
5310 static void migrate_nr_uninterruptible(struct rq *rq_src)
5312 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
5314 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
5315 rq_src->nr_uninterruptible = 0;
5319 * remove the tasks which were accounted by rq from calc_load_tasks.
5321 static void calc_global_load_remove(struct rq *rq)
5323 atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
5324 rq->calc_load_active = 0;
5328 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5329 * try_to_wake_up()->select_task_rq().
5331 * Called with rq->lock held even though we'er in stop_machine() and
5332 * there's no concurrency possible, we hold the required locks anyway
5333 * because of lock validation efforts.
5335 static void migrate_tasks(unsigned int dead_cpu)
5337 struct rq *rq = cpu_rq(dead_cpu);
5338 struct task_struct *next, *stop = rq->stop;
5342 * Fudge the rq selection such that the below task selection loop
5343 * doesn't get stuck on the currently eligible stop task.
5345 * We're currently inside stop_machine() and the rq is either stuck
5346 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5347 * either way we should never end up calling schedule() until we're
5352 /* Ensure any throttled groups are reachable by pick_next_task */
5353 unthrottle_offline_cfs_rqs(rq);
5357 * There's this thread running, bail when that's the only
5360 if (rq->nr_running == 1)
5363 next = pick_next_task(rq);
5365 next->sched_class->put_prev_task(rq, next);
5367 /* Find suitable destination for @next, with force if needed. */
5368 dest_cpu = select_fallback_rq(dead_cpu, next);
5369 raw_spin_unlock(&rq->lock);
5371 __migrate_task(next, dead_cpu, dest_cpu);
5373 raw_spin_lock(&rq->lock);
5379 #endif /* CONFIG_HOTPLUG_CPU */
5381 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5383 static struct ctl_table sd_ctl_dir[] = {
5385 .procname = "sched_domain",
5391 static struct ctl_table sd_ctl_root[] = {
5393 .procname = "kernel",
5395 .child = sd_ctl_dir,
5400 static struct ctl_table *sd_alloc_ctl_entry(int n)
5402 struct ctl_table *entry =
5403 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
5408 static void sd_free_ctl_entry(struct ctl_table **tablep)
5410 struct ctl_table *entry;
5413 * In the intermediate directories, both the child directory and
5414 * procname are dynamically allocated and could fail but the mode
5415 * will always be set. In the lowest directory the names are
5416 * static strings and all have proc handlers.
5418 for (entry = *tablep; entry->mode; entry++) {
5420 sd_free_ctl_entry(&entry->child);
5421 if (entry->proc_handler == NULL)
5422 kfree(entry->procname);
5430 set_table_entry(struct ctl_table *entry,
5431 const char *procname, void *data, int maxlen,
5432 umode_t mode, proc_handler *proc_handler)
5434 entry->procname = procname;
5436 entry->maxlen = maxlen;
5438 entry->proc_handler = proc_handler;
5441 static struct ctl_table *
5442 sd_alloc_ctl_domain_table(struct sched_domain *sd)
5444 struct ctl_table *table = sd_alloc_ctl_entry(13);
5449 set_table_entry(&table[0], "min_interval", &sd->min_interval,
5450 sizeof(long), 0644, proc_doulongvec_minmax);
5451 set_table_entry(&table[1], "max_interval", &sd->max_interval,
5452 sizeof(long), 0644, proc_doulongvec_minmax);
5453 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
5454 sizeof(int), 0644, proc_dointvec_minmax);
5455 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
5456 sizeof(int), 0644, proc_dointvec_minmax);
5457 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
5458 sizeof(int), 0644, proc_dointvec_minmax);
5459 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
5460 sizeof(int), 0644, proc_dointvec_minmax);
5461 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
5462 sizeof(int), 0644, proc_dointvec_minmax);
5463 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
5464 sizeof(int), 0644, proc_dointvec_minmax);
5465 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
5466 sizeof(int), 0644, proc_dointvec_minmax);
5467 set_table_entry(&table[9], "cache_nice_tries",
5468 &sd->cache_nice_tries,
5469 sizeof(int), 0644, proc_dointvec_minmax);
5470 set_table_entry(&table[10], "flags", &sd->flags,
5471 sizeof(int), 0644, proc_dointvec_minmax);
5472 set_table_entry(&table[11], "name", sd->name,
5473 CORENAME_MAX_SIZE, 0444, proc_dostring);
5474 /* &table[12] is terminator */
5479 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
5481 struct ctl_table *entry, *table;
5482 struct sched_domain *sd;
5483 int domain_num = 0, i;
5486 for_each_domain(cpu, sd)
5488 entry = table = sd_alloc_ctl_entry(domain_num + 1);
5493 for_each_domain(cpu, sd) {
5494 snprintf(buf, 32, "domain%d", i);
5495 entry->procname = kstrdup(buf, GFP_KERNEL);
5497 entry->child = sd_alloc_ctl_domain_table(sd);
5504 static struct ctl_table_header *sd_sysctl_header;
5505 static void register_sched_domain_sysctl(void)
5507 int i, cpu_num = num_possible_cpus();
5508 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
5511 WARN_ON(sd_ctl_dir[0].child);
5512 sd_ctl_dir[0].child = entry;
5517 for_each_possible_cpu(i) {
5518 snprintf(buf, 32, "cpu%d", i);
5519 entry->procname = kstrdup(buf, GFP_KERNEL);
5521 entry->child = sd_alloc_ctl_cpu_table(i);
5525 WARN_ON(sd_sysctl_header);
5526 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
5529 /* may be called multiple times per register */
5530 static void unregister_sched_domain_sysctl(void)
5532 if (sd_sysctl_header)
5533 unregister_sysctl_table(sd_sysctl_header);
5534 sd_sysctl_header = NULL;
5535 if (sd_ctl_dir[0].child)
5536 sd_free_ctl_entry(&sd_ctl_dir[0].child);
5539 static void register_sched_domain_sysctl(void)
5542 static void unregister_sched_domain_sysctl(void)
5547 static void set_rq_online(struct rq *rq)
5550 const struct sched_class *class;
5552 cpumask_set_cpu(rq->cpu, rq->rd->online);
5555 for_each_class(class) {
5556 if (class->rq_online)
5557 class->rq_online(rq);
5562 static void set_rq_offline(struct rq *rq)
5565 const struct sched_class *class;
5567 for_each_class(class) {
5568 if (class->rq_offline)
5569 class->rq_offline(rq);
5572 cpumask_clear_cpu(rq->cpu, rq->rd->online);
5578 * migration_call - callback that gets triggered when a CPU is added.
5579 * Here we can start up the necessary migration thread for the new CPU.
5581 static int __cpuinit
5582 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
5584 int cpu = (long)hcpu;
5585 unsigned long flags;
5586 struct rq *rq = cpu_rq(cpu);
5588 switch (action & ~CPU_TASKS_FROZEN) {
5590 case CPU_UP_PREPARE:
5591 rq->calc_load_update = calc_load_update;
5595 /* Update our root-domain */
5596 raw_spin_lock_irqsave(&rq->lock, flags);
5598 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5602 raw_spin_unlock_irqrestore(&rq->lock, flags);
5605 #ifdef CONFIG_HOTPLUG_CPU
5607 sched_ttwu_pending();
5608 /* Update our root-domain */
5609 raw_spin_lock_irqsave(&rq->lock, flags);
5611 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5615 BUG_ON(rq->nr_running != 1); /* the migration thread */
5616 raw_spin_unlock_irqrestore(&rq->lock, flags);
5618 migrate_nr_uninterruptible(rq);
5619 calc_global_load_remove(rq);
5624 update_max_interval();
5630 * Register at high priority so that task migration (migrate_all_tasks)
5631 * happens before everything else. This has to be lower priority than
5632 * the notifier in the perf_event subsystem, though.
5634 static struct notifier_block __cpuinitdata migration_notifier = {
5635 .notifier_call = migration_call,
5636 .priority = CPU_PRI_MIGRATION,
5639 static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
5640 unsigned long action, void *hcpu)
5642 switch (action & ~CPU_TASKS_FROZEN) {
5644 case CPU_DOWN_FAILED:
5645 set_cpu_active((long)hcpu, true);
5652 static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
5653 unsigned long action, void *hcpu)
5655 switch (action & ~CPU_TASKS_FROZEN) {
5656 case CPU_DOWN_PREPARE:
5657 set_cpu_active((long)hcpu, false);
5664 static int __init migration_init(void)
5666 void *cpu = (void *)(long)smp_processor_id();
5669 /* Initialize migration for the boot CPU */
5670 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
5671 BUG_ON(err == NOTIFY_BAD);
5672 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5673 register_cpu_notifier(&migration_notifier);
5675 /* Register cpu active notifiers */
5676 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
5677 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
5681 early_initcall(migration_init);
5686 static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
5688 #ifdef CONFIG_SCHED_DEBUG
5690 static __read_mostly int sched_debug_enabled;
5692 static int __init sched_debug_setup(char *str)
5694 sched_debug_enabled = 1;
5698 early_param("sched_debug", sched_debug_setup);
5700 static inline bool sched_debug(void)
5702 return sched_debug_enabled;
5705 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
5706 struct cpumask *groupmask)
5708 struct sched_group *group = sd->groups;
5711 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
5712 cpumask_clear(groupmask);
5714 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
5716 if (!(sd->flags & SD_LOAD_BALANCE)) {
5717 printk("does not load-balance\n");
5719 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
5724 printk(KERN_CONT "span %s level %s\n", str, sd->name);
5726 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
5727 printk(KERN_ERR "ERROR: domain->span does not contain "
5730 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
5731 printk(KERN_ERR "ERROR: domain->groups does not contain"
5735 printk(KERN_DEBUG "%*s groups:", level + 1, "");
5739 printk(KERN_ERR "ERROR: group is NULL\n");
5744 * Even though we initialize ->power to something semi-sane,
5745 * we leave power_orig unset. This allows us to detect if
5746 * domain iteration is still funny without causing /0 traps.
5748 if (!group->sgp->power_orig) {
5749 printk(KERN_CONT "\n");
5750 printk(KERN_ERR "ERROR: domain->cpu_power not "
5755 if (!cpumask_weight(sched_group_cpus(group))) {
5756 printk(KERN_CONT "\n");
5757 printk(KERN_ERR "ERROR: empty group\n");
5761 if (!(sd->flags & SD_OVERLAP) &&
5762 cpumask_intersects(groupmask, sched_group_cpus(group))) {
5763 printk(KERN_CONT "\n");
5764 printk(KERN_ERR "ERROR: repeated CPUs\n");
5768 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
5770 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
5772 printk(KERN_CONT " %s", str);
5773 if (group->sgp->power != SCHED_POWER_SCALE) {
5774 printk(KERN_CONT " (cpu_power = %d)",
5778 group = group->next;
5779 } while (group != sd->groups);
5780 printk(KERN_CONT "\n");
5782 if (!cpumask_equal(sched_domain_span(sd), groupmask))
5783 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
5786 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
5787 printk(KERN_ERR "ERROR: parent span is not a superset "
5788 "of domain->span\n");
5792 static void sched_domain_debug(struct sched_domain *sd, int cpu)
5796 if (!sched_debug_enabled)
5800 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
5804 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
5807 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
5815 #else /* !CONFIG_SCHED_DEBUG */
5816 # define sched_domain_debug(sd, cpu) do { } while (0)
5817 static inline bool sched_debug(void)
5821 #endif /* CONFIG_SCHED_DEBUG */
5823 static int sd_degenerate(struct sched_domain *sd)
5825 if (cpumask_weight(sched_domain_span(sd)) == 1)
5828 /* Following flags need at least 2 groups */
5829 if (sd->flags & (SD_LOAD_BALANCE |
5830 SD_BALANCE_NEWIDLE |
5834 SD_SHARE_PKG_RESOURCES)) {
5835 if (sd->groups != sd->groups->next)
5839 /* Following flags don't use groups */
5840 if (sd->flags & (SD_WAKE_AFFINE))
5847 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
5849 unsigned long cflags = sd->flags, pflags = parent->flags;
5851 if (sd_degenerate(parent))
5854 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
5857 /* Flags needing groups don't count if only 1 group in parent */
5858 if (parent->groups == parent->groups->next) {
5859 pflags &= ~(SD_LOAD_BALANCE |
5860 SD_BALANCE_NEWIDLE |
5864 SD_SHARE_PKG_RESOURCES);
5865 if (nr_node_ids == 1)
5866 pflags &= ~SD_SERIALIZE;
5868 if (~cflags & pflags)
5874 static void free_rootdomain(struct rcu_head *rcu)
5876 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
5878 cpupri_cleanup(&rd->cpupri);
5879 free_cpumask_var(rd->rto_mask);
5880 free_cpumask_var(rd->online);
5881 free_cpumask_var(rd->span);
5885 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
5887 struct root_domain *old_rd = NULL;
5888 unsigned long flags;
5890 raw_spin_lock_irqsave(&rq->lock, flags);
5895 if (cpumask_test_cpu(rq->cpu, old_rd->online))
5898 cpumask_clear_cpu(rq->cpu, old_rd->span);
5901 * If we dont want to free the old_rt yet then
5902 * set old_rd to NULL to skip the freeing later
5905 if (!atomic_dec_and_test(&old_rd->refcount))
5909 atomic_inc(&rd->refcount);
5912 cpumask_set_cpu(rq->cpu, rd->span);
5913 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
5916 raw_spin_unlock_irqrestore(&rq->lock, flags);
5919 call_rcu_sched(&old_rd->rcu, free_rootdomain);
5922 static int init_rootdomain(struct root_domain *rd)
5924 memset(rd, 0, sizeof(*rd));
5926 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
5928 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
5930 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
5933 if (cpupri_init(&rd->cpupri) != 0)
5938 free_cpumask_var(rd->rto_mask);
5940 free_cpumask_var(rd->online);
5942 free_cpumask_var(rd->span);
5948 * By default the system creates a single root-domain with all cpus as
5949 * members (mimicking the global state we have today).
5951 struct root_domain def_root_domain;
5953 static void init_defrootdomain(void)
5955 init_rootdomain(&def_root_domain);
5957 atomic_set(&def_root_domain.refcount, 1);
5960 static struct root_domain *alloc_rootdomain(void)
5962 struct root_domain *rd;
5964 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
5968 if (init_rootdomain(rd) != 0) {
5976 static void free_sched_groups(struct sched_group *sg, int free_sgp)
5978 struct sched_group *tmp, *first;
5987 if (free_sgp && atomic_dec_and_test(&sg->sgp->ref))
5992 } while (sg != first);
5995 static void free_sched_domain(struct rcu_head *rcu)
5997 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
6000 * If its an overlapping domain it has private groups, iterate and
6003 if (sd->flags & SD_OVERLAP) {
6004 free_sched_groups(sd->groups, 1);
6005 } else if (atomic_dec_and_test(&sd->groups->ref)) {
6006 kfree(sd->groups->sgp);
6012 static void destroy_sched_domain(struct sched_domain *sd, int cpu)
6014 call_rcu(&sd->rcu, free_sched_domain);
6017 static void destroy_sched_domains(struct sched_domain *sd, int cpu)
6019 for (; sd; sd = sd->parent)
6020 destroy_sched_domain(sd, cpu);
6024 * Keep a special pointer to the highest sched_domain that has
6025 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
6026 * allows us to avoid some pointer chasing select_idle_sibling().
6028 * Also keep a unique ID per domain (we use the first cpu number in
6029 * the cpumask of the domain), this allows us to quickly tell if
6030 * two cpus are in the same cache domain, see cpus_share_cache().
6032 DEFINE_PER_CPU(struct sched_domain *, sd_llc);
6033 DEFINE_PER_CPU(int, sd_llc_id);
6035 static void update_top_cache_domain(int cpu)
6037 struct sched_domain *sd;
6040 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
6042 id = cpumask_first(sched_domain_span(sd));
6044 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
6045 per_cpu(sd_llc_id, cpu) = id;
6049 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6050 * hold the hotplug lock.
6053 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
6055 struct rq *rq = cpu_rq(cpu);
6056 struct sched_domain *tmp;
6058 /* Remove the sched domains which do not contribute to scheduling. */
6059 for (tmp = sd; tmp; ) {
6060 struct sched_domain *parent = tmp->parent;
6064 if (sd_parent_degenerate(tmp, parent)) {
6065 tmp->parent = parent->parent;
6067 parent->parent->child = tmp;
6068 destroy_sched_domain(parent, cpu);
6073 if (sd && sd_degenerate(sd)) {
6076 destroy_sched_domain(tmp, cpu);
6081 sched_domain_debug(sd, cpu);
6083 rq_attach_root(rq, rd);
6085 rcu_assign_pointer(rq->sd, sd);
6086 destroy_sched_domains(tmp, cpu);
6088 update_top_cache_domain(cpu);
6091 /* cpus with isolated domains */
6092 static cpumask_var_t cpu_isolated_map;
6094 /* Setup the mask of cpus configured for isolated domains */
6095 static int __init isolated_cpu_setup(char *str)
6097 alloc_bootmem_cpumask_var(&cpu_isolated_map);
6098 cpulist_parse(str, cpu_isolated_map);
6102 __setup("isolcpus=", isolated_cpu_setup);
6104 static const struct cpumask *cpu_cpu_mask(int cpu)
6106 return cpumask_of_node(cpu_to_node(cpu));
6110 struct sched_domain **__percpu sd;
6111 struct sched_group **__percpu sg;
6112 struct sched_group_power **__percpu sgp;
6116 struct sched_domain ** __percpu sd;
6117 struct root_domain *rd;
6127 struct sched_domain_topology_level;
6129 typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
6130 typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
6132 #define SDTL_OVERLAP 0x01
6134 struct sched_domain_topology_level {
6135 sched_domain_init_f init;
6136 sched_domain_mask_f mask;
6139 struct sd_data data;
6143 * Build an iteration mask that can exclude certain CPUs from the upwards
6146 * Asymmetric node setups can result in situations where the domain tree is of
6147 * unequal depth, make sure to skip domains that already cover the entire
6150 * In that case build_sched_domains() will have terminated the iteration early
6151 * and our sibling sd spans will be empty. Domains should always include the
6152 * cpu they're built on, so check that.
6155 static void build_group_mask(struct sched_domain *sd, struct sched_group *sg)
6157 const struct cpumask *span = sched_domain_span(sd);
6158 struct sd_data *sdd = sd->private;
6159 struct sched_domain *sibling;
6162 for_each_cpu(i, span) {
6163 sibling = *per_cpu_ptr(sdd->sd, i);
6164 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
6167 cpumask_set_cpu(i, sched_group_mask(sg));
6172 * Return the canonical balance cpu for this group, this is the first cpu
6173 * of this group that's also in the iteration mask.
6175 int group_balance_cpu(struct sched_group *sg)
6177 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg));
6181 build_overlap_sched_groups(struct sched_domain *sd, int cpu)
6183 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
6184 const struct cpumask *span = sched_domain_span(sd);
6185 struct cpumask *covered = sched_domains_tmpmask;
6186 struct sd_data *sdd = sd->private;
6187 struct sched_domain *child;
6190 cpumask_clear(covered);
6192 for_each_cpu(i, span) {
6193 struct cpumask *sg_span;
6195 if (cpumask_test_cpu(i, covered))
6198 child = *per_cpu_ptr(sdd->sd, i);
6200 /* See the comment near build_group_mask(). */
6201 if (!cpumask_test_cpu(i, sched_domain_span(child)))
6204 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
6205 GFP_KERNEL, cpu_to_node(cpu));
6210 sg_span = sched_group_cpus(sg);
6212 child = child->child;
6213 cpumask_copy(sg_span, sched_domain_span(child));
6215 cpumask_set_cpu(i, sg_span);
6217 cpumask_or(covered, covered, sg_span);
6219 sg->sgp = *per_cpu_ptr(sdd->sgp, i);
6220 if (atomic_inc_return(&sg->sgp->ref) == 1)
6221 build_group_mask(sd, sg);
6224 * Initialize sgp->power such that even if we mess up the
6225 * domains and no possible iteration will get us here, we won't
6228 sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span);
6231 * Make sure the first group of this domain contains the
6232 * canonical balance cpu. Otherwise the sched_domain iteration
6233 * breaks. See update_sg_lb_stats().
6235 if ((!groups && cpumask_test_cpu(cpu, sg_span)) ||
6236 group_balance_cpu(sg) == cpu)
6246 sd->groups = groups;
6251 free_sched_groups(first, 0);
6256 static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
6258 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
6259 struct sched_domain *child = sd->child;
6262 cpu = cpumask_first(sched_domain_span(child));
6265 *sg = *per_cpu_ptr(sdd->sg, cpu);
6266 (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu);
6267 atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */
6274 * build_sched_groups will build a circular linked list of the groups
6275 * covered by the given span, and will set each group's ->cpumask correctly,
6276 * and ->cpu_power to 0.
6278 * Assumes the sched_domain tree is fully constructed
6281 build_sched_groups(struct sched_domain *sd, int cpu)
6283 struct sched_group *first = NULL, *last = NULL;
6284 struct sd_data *sdd = sd->private;
6285 const struct cpumask *span = sched_domain_span(sd);
6286 struct cpumask *covered;
6289 get_group(cpu, sdd, &sd->groups);
6290 atomic_inc(&sd->groups->ref);
6292 if (cpu != cpumask_first(sched_domain_span(sd)))
6295 lockdep_assert_held(&sched_domains_mutex);
6296 covered = sched_domains_tmpmask;
6298 cpumask_clear(covered);
6300 for_each_cpu(i, span) {
6301 struct sched_group *sg;
6302 int group = get_group(i, sdd, &sg);
6305 if (cpumask_test_cpu(i, covered))
6308 cpumask_clear(sched_group_cpus(sg));
6310 cpumask_setall(sched_group_mask(sg));
6312 for_each_cpu(j, span) {
6313 if (get_group(j, sdd, NULL) != group)
6316 cpumask_set_cpu(j, covered);
6317 cpumask_set_cpu(j, sched_group_cpus(sg));
6332 * Initialize sched groups cpu_power.
6334 * cpu_power indicates the capacity of sched group, which is used while
6335 * distributing the load between different sched groups in a sched domain.
6336 * Typically cpu_power for all the groups in a sched domain will be same unless
6337 * there are asymmetries in the topology. If there are asymmetries, group
6338 * having more cpu_power will pickup more load compared to the group having
6341 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
6343 struct sched_group *sg = sd->groups;
6345 WARN_ON(!sd || !sg);
6348 sg->group_weight = cpumask_weight(sched_group_cpus(sg));
6350 } while (sg != sd->groups);
6352 if (cpu != group_balance_cpu(sg))
6355 update_group_power(sd, cpu);
6356 atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
6359 int __weak arch_sd_sibling_asym_packing(void)
6361 return 0*SD_ASYM_PACKING;
6365 * Initializers for schedule domains
6366 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6369 #ifdef CONFIG_SCHED_DEBUG
6370 # define SD_INIT_NAME(sd, type) sd->name = #type
6372 # define SD_INIT_NAME(sd, type) do { } while (0)
6375 #define SD_INIT_FUNC(type) \
6376 static noinline struct sched_domain * \
6377 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
6379 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
6380 *sd = SD_##type##_INIT; \
6381 SD_INIT_NAME(sd, type); \
6382 sd->private = &tl->data; \
6387 #ifdef CONFIG_SCHED_SMT
6388 SD_INIT_FUNC(SIBLING)
6390 #ifdef CONFIG_SCHED_MC
6393 #ifdef CONFIG_SCHED_BOOK
6397 static int default_relax_domain_level = -1;
6398 int sched_domain_level_max;
6400 static int __init setup_relax_domain_level(char *str)
6402 if (kstrtoint(str, 0, &default_relax_domain_level))
6403 pr_warn("Unable to set relax_domain_level\n");
6407 __setup("relax_domain_level=", setup_relax_domain_level);
6409 static void set_domain_attribute(struct sched_domain *sd,
6410 struct sched_domain_attr *attr)
6414 if (!attr || attr->relax_domain_level < 0) {
6415 if (default_relax_domain_level < 0)
6418 request = default_relax_domain_level;
6420 request = attr->relax_domain_level;
6421 if (request < sd->level) {
6422 /* turn off idle balance on this domain */
6423 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6425 /* turn on idle balance on this domain */
6426 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6430 static void __sdt_free(const struct cpumask *cpu_map);
6431 static int __sdt_alloc(const struct cpumask *cpu_map);
6433 static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
6434 const struct cpumask *cpu_map)
6438 if (!atomic_read(&d->rd->refcount))
6439 free_rootdomain(&d->rd->rcu); /* fall through */
6441 free_percpu(d->sd); /* fall through */
6443 __sdt_free(cpu_map); /* fall through */
6449 static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
6450 const struct cpumask *cpu_map)
6452 memset(d, 0, sizeof(*d));
6454 if (__sdt_alloc(cpu_map))
6455 return sa_sd_storage;
6456 d->sd = alloc_percpu(struct sched_domain *);
6458 return sa_sd_storage;
6459 d->rd = alloc_rootdomain();
6462 return sa_rootdomain;
6466 * NULL the sd_data elements we've used to build the sched_domain and
6467 * sched_group structure so that the subsequent __free_domain_allocs()
6468 * will not free the data we're using.
6470 static void claim_allocations(int cpu, struct sched_domain *sd)
6472 struct sd_data *sdd = sd->private;
6474 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
6475 *per_cpu_ptr(sdd->sd, cpu) = NULL;
6477 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
6478 *per_cpu_ptr(sdd->sg, cpu) = NULL;
6480 if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref))
6481 *per_cpu_ptr(sdd->sgp, cpu) = NULL;
6484 #ifdef CONFIG_SCHED_SMT
6485 static const struct cpumask *cpu_smt_mask(int cpu)
6487 return topology_thread_cpumask(cpu);
6492 * Topology list, bottom-up.
6494 static struct sched_domain_topology_level default_topology[] = {
6495 #ifdef CONFIG_SCHED_SMT
6496 { sd_init_SIBLING, cpu_smt_mask, },
6498 #ifdef CONFIG_SCHED_MC
6499 { sd_init_MC, cpu_coregroup_mask, },
6501 #ifdef CONFIG_SCHED_BOOK
6502 { sd_init_BOOK, cpu_book_mask, },
6504 { sd_init_CPU, cpu_cpu_mask, },
6508 static struct sched_domain_topology_level *sched_domain_topology = default_topology;
6512 static int sched_domains_numa_levels;
6513 static int *sched_domains_numa_distance;
6514 static struct cpumask ***sched_domains_numa_masks;
6515 static int sched_domains_curr_level;
6517 static inline int sd_local_flags(int level)
6519 if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE)
6522 return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE;
6525 static struct sched_domain *
6526 sd_numa_init(struct sched_domain_topology_level *tl, int cpu)
6528 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
6529 int level = tl->numa_level;
6530 int sd_weight = cpumask_weight(
6531 sched_domains_numa_masks[level][cpu_to_node(cpu)]);
6533 *sd = (struct sched_domain){
6534 .min_interval = sd_weight,
6535 .max_interval = 2*sd_weight,
6537 .imbalance_pct = 125,
6538 .cache_nice_tries = 2,
6545 .flags = 1*SD_LOAD_BALANCE
6546 | 1*SD_BALANCE_NEWIDLE
6552 | 0*SD_SHARE_CPUPOWER
6553 | 0*SD_SHARE_PKG_RESOURCES
6555 | 0*SD_PREFER_SIBLING
6556 | sd_local_flags(level)
6558 .last_balance = jiffies,
6559 .balance_interval = sd_weight,
6561 SD_INIT_NAME(sd, NUMA);
6562 sd->private = &tl->data;
6565 * Ugly hack to pass state to sd_numa_mask()...
6567 sched_domains_curr_level = tl->numa_level;
6572 static const struct cpumask *sd_numa_mask(int cpu)
6574 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
6577 static void sched_numa_warn(const char *str)
6579 static int done = false;
6587 printk(KERN_WARNING "ERROR: %s\n\n", str);
6589 for (i = 0; i < nr_node_ids; i++) {
6590 printk(KERN_WARNING " ");
6591 for (j = 0; j < nr_node_ids; j++)
6592 printk(KERN_CONT "%02d ", node_distance(i,j));
6593 printk(KERN_CONT "\n");
6595 printk(KERN_WARNING "\n");
6598 static bool find_numa_distance(int distance)
6602 if (distance == node_distance(0, 0))
6605 for (i = 0; i < sched_domains_numa_levels; i++) {
6606 if (sched_domains_numa_distance[i] == distance)
6613 static void sched_init_numa(void)
6615 int next_distance, curr_distance = node_distance(0, 0);
6616 struct sched_domain_topology_level *tl;
6620 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL);
6621 if (!sched_domains_numa_distance)
6625 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6626 * unique distances in the node_distance() table.
6628 * Assumes node_distance(0,j) includes all distances in
6629 * node_distance(i,j) in order to avoid cubic time.
6631 next_distance = curr_distance;
6632 for (i = 0; i < nr_node_ids; i++) {
6633 for (j = 0; j < nr_node_ids; j++) {
6634 for (k = 0; k < nr_node_ids; k++) {
6635 int distance = node_distance(i, k);
6637 if (distance > curr_distance &&
6638 (distance < next_distance ||
6639 next_distance == curr_distance))
6640 next_distance = distance;
6643 * While not a strong assumption it would be nice to know
6644 * about cases where if node A is connected to B, B is not
6645 * equally connected to A.
6647 if (sched_debug() && node_distance(k, i) != distance)
6648 sched_numa_warn("Node-distance not symmetric");
6650 if (sched_debug() && i && !find_numa_distance(distance))
6651 sched_numa_warn("Node-0 not representative");
6653 if (next_distance != curr_distance) {
6654 sched_domains_numa_distance[level++] = next_distance;
6655 sched_domains_numa_levels = level;
6656 curr_distance = next_distance;
6661 * In case of sched_debug() we verify the above assumption.
6667 * 'level' contains the number of unique distances, excluding the
6668 * identity distance node_distance(i,i).
6670 * The sched_domains_nume_distance[] array includes the actual distance
6674 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
6675 if (!sched_domains_numa_masks)
6679 * Now for each level, construct a mask per node which contains all
6680 * cpus of nodes that are that many hops away from us.
6682 for (i = 0; i < level; i++) {
6683 sched_domains_numa_masks[i] =
6684 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
6685 if (!sched_domains_numa_masks[i])
6688 for (j = 0; j < nr_node_ids; j++) {
6689 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
6693 sched_domains_numa_masks[i][j] = mask;
6695 for (k = 0; k < nr_node_ids; k++) {
6696 if (node_distance(j, k) > sched_domains_numa_distance[i])
6699 cpumask_or(mask, mask, cpumask_of_node(k));
6704 tl = kzalloc((ARRAY_SIZE(default_topology) + level) *
6705 sizeof(struct sched_domain_topology_level), GFP_KERNEL);
6710 * Copy the default topology bits..
6712 for (i = 0; default_topology[i].init; i++)
6713 tl[i] = default_topology[i];
6716 * .. and append 'j' levels of NUMA goodness.
6718 for (j = 0; j < level; i++, j++) {
6719 tl[i] = (struct sched_domain_topology_level){
6720 .init = sd_numa_init,
6721 .mask = sd_numa_mask,
6722 .flags = SDTL_OVERLAP,
6727 sched_domain_topology = tl;
6730 static inline void sched_init_numa(void)
6733 #endif /* CONFIG_NUMA */
6735 static int __sdt_alloc(const struct cpumask *cpu_map)
6737 struct sched_domain_topology_level *tl;
6740 for (tl = sched_domain_topology; tl->init; tl++) {
6741 struct sd_data *sdd = &tl->data;
6743 sdd->sd = alloc_percpu(struct sched_domain *);
6747 sdd->sg = alloc_percpu(struct sched_group *);
6751 sdd->sgp = alloc_percpu(struct sched_group_power *);
6755 for_each_cpu(j, cpu_map) {
6756 struct sched_domain *sd;
6757 struct sched_group *sg;
6758 struct sched_group_power *sgp;
6760 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
6761 GFP_KERNEL, cpu_to_node(j));
6765 *per_cpu_ptr(sdd->sd, j) = sd;
6767 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
6768 GFP_KERNEL, cpu_to_node(j));
6774 *per_cpu_ptr(sdd->sg, j) = sg;
6776 sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(),
6777 GFP_KERNEL, cpu_to_node(j));
6781 *per_cpu_ptr(sdd->sgp, j) = sgp;
6788 static void __sdt_free(const struct cpumask *cpu_map)
6790 struct sched_domain_topology_level *tl;
6793 for (tl = sched_domain_topology; tl->init; tl++) {
6794 struct sd_data *sdd = &tl->data;
6796 for_each_cpu(j, cpu_map) {
6797 struct sched_domain *sd;
6800 sd = *per_cpu_ptr(sdd->sd, j);
6801 if (sd && (sd->flags & SD_OVERLAP))
6802 free_sched_groups(sd->groups, 0);
6803 kfree(*per_cpu_ptr(sdd->sd, j));
6807 kfree(*per_cpu_ptr(sdd->sg, j));
6809 kfree(*per_cpu_ptr(sdd->sgp, j));
6811 free_percpu(sdd->sd);
6813 free_percpu(sdd->sg);
6815 free_percpu(sdd->sgp);
6820 struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
6821 struct s_data *d, const struct cpumask *cpu_map,
6822 struct sched_domain_attr *attr, struct sched_domain *child,
6825 struct sched_domain *sd = tl->init(tl, cpu);
6829 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
6831 sd->level = child->level + 1;
6832 sched_domain_level_max = max(sched_domain_level_max, sd->level);
6836 set_domain_attribute(sd, attr);
6842 * Build sched domains for a given set of cpus and attach the sched domains
6843 * to the individual cpus
6845 static int build_sched_domains(const struct cpumask *cpu_map,
6846 struct sched_domain_attr *attr)
6848 enum s_alloc alloc_state = sa_none;
6849 struct sched_domain *sd;
6851 int i, ret = -ENOMEM;
6853 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
6854 if (alloc_state != sa_rootdomain)
6857 /* Set up domains for cpus specified by the cpu_map. */
6858 for_each_cpu(i, cpu_map) {
6859 struct sched_domain_topology_level *tl;
6862 for (tl = sched_domain_topology; tl->init; tl++) {
6863 sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);
6864 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
6865 sd->flags |= SD_OVERLAP;
6866 if (cpumask_equal(cpu_map, sched_domain_span(sd)))
6873 *per_cpu_ptr(d.sd, i) = sd;
6876 /* Build the groups for the domains */
6877 for_each_cpu(i, cpu_map) {
6878 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6879 sd->span_weight = cpumask_weight(sched_domain_span(sd));
6880 if (sd->flags & SD_OVERLAP) {
6881 if (build_overlap_sched_groups(sd, i))
6884 if (build_sched_groups(sd, i))
6890 /* Calculate CPU power for physical packages and nodes */
6891 for (i = nr_cpumask_bits-1; i >= 0; i--) {
6892 if (!cpumask_test_cpu(i, cpu_map))
6895 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6896 claim_allocations(i, sd);
6897 init_sched_groups_power(i, sd);
6901 /* Attach the domains */
6903 for_each_cpu(i, cpu_map) {
6904 sd = *per_cpu_ptr(d.sd, i);
6905 cpu_attach_domain(sd, d.rd, i);
6911 __free_domain_allocs(&d, alloc_state, cpu_map);
6915 static cpumask_var_t *doms_cur; /* current sched domains */
6916 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
6917 static struct sched_domain_attr *dattr_cur;
6918 /* attribues of custom domains in 'doms_cur' */
6921 * Special case: If a kmalloc of a doms_cur partition (array of
6922 * cpumask) fails, then fallback to a single sched domain,
6923 * as determined by the single cpumask fallback_doms.
6925 static cpumask_var_t fallback_doms;
6928 * arch_update_cpu_topology lets virtualized architectures update the
6929 * cpu core maps. It is supposed to return 1 if the topology changed
6930 * or 0 if it stayed the same.
6932 int __attribute__((weak)) arch_update_cpu_topology(void)
6937 cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
6940 cpumask_var_t *doms;
6942 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
6945 for (i = 0; i < ndoms; i++) {
6946 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
6947 free_sched_domains(doms, i);
6954 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
6957 for (i = 0; i < ndoms; i++)
6958 free_cpumask_var(doms[i]);
6963 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6964 * For now this just excludes isolated cpus, but could be used to
6965 * exclude other special cases in the future.
6967 static int init_sched_domains(const struct cpumask *cpu_map)
6971 arch_update_cpu_topology();
6973 doms_cur = alloc_sched_domains(ndoms_cur);
6975 doms_cur = &fallback_doms;
6976 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
6977 err = build_sched_domains(doms_cur[0], NULL);
6978 register_sched_domain_sysctl();
6984 * Detach sched domains from a group of cpus specified in cpu_map
6985 * These cpus will now be attached to the NULL domain
6987 static void detach_destroy_domains(const struct cpumask *cpu_map)
6992 for_each_cpu(i, cpu_map)
6993 cpu_attach_domain(NULL, &def_root_domain, i);
6997 /* handle null as "default" */
6998 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
6999 struct sched_domain_attr *new, int idx_new)
7001 struct sched_domain_attr tmp;
7008 return !memcmp(cur ? (cur + idx_cur) : &tmp,
7009 new ? (new + idx_new) : &tmp,
7010 sizeof(struct sched_domain_attr));
7014 * Partition sched domains as specified by the 'ndoms_new'
7015 * cpumasks in the array doms_new[] of cpumasks. This compares
7016 * doms_new[] to the current sched domain partitioning, doms_cur[].
7017 * It destroys each deleted domain and builds each new domain.
7019 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7020 * The masks don't intersect (don't overlap.) We should setup one
7021 * sched domain for each mask. CPUs not in any of the cpumasks will
7022 * not be load balanced. If the same cpumask appears both in the
7023 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7026 * The passed in 'doms_new' should be allocated using
7027 * alloc_sched_domains. This routine takes ownership of it and will
7028 * free_sched_domains it when done with it. If the caller failed the
7029 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7030 * and partition_sched_domains() will fallback to the single partition
7031 * 'fallback_doms', it also forces the domains to be rebuilt.
7033 * If doms_new == NULL it will be replaced with cpu_online_mask.
7034 * ndoms_new == 0 is a special case for destroying existing domains,
7035 * and it will not create the default domain.
7037 * Call with hotplug lock held
7039 void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
7040 struct sched_domain_attr *dattr_new)
7045 mutex_lock(&sched_domains_mutex);
7047 /* always unregister in case we don't destroy any domains */
7048 unregister_sched_domain_sysctl();
7050 /* Let architecture update cpu core mappings. */
7051 new_topology = arch_update_cpu_topology();
7053 n = doms_new ? ndoms_new : 0;
7055 /* Destroy deleted domains */
7056 for (i = 0; i < ndoms_cur; i++) {
7057 for (j = 0; j < n && !new_topology; j++) {
7058 if (cpumask_equal(doms_cur[i], doms_new[j])
7059 && dattrs_equal(dattr_cur, i, dattr_new, j))
7062 /* no match - a current sched domain not in new doms_new[] */
7063 detach_destroy_domains(doms_cur[i]);
7068 if (doms_new == NULL) {
7070 doms_new = &fallback_doms;
7071 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
7072 WARN_ON_ONCE(dattr_new);
7075 /* Build new domains */
7076 for (i = 0; i < ndoms_new; i++) {
7077 for (j = 0; j < ndoms_cur && !new_topology; j++) {
7078 if (cpumask_equal(doms_new[i], doms_cur[j])
7079 && dattrs_equal(dattr_new, i, dattr_cur, j))
7082 /* no match - add a new doms_new */
7083 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
7088 /* Remember the new sched domains */
7089 if (doms_cur != &fallback_doms)
7090 free_sched_domains(doms_cur, ndoms_cur);
7091 kfree(dattr_cur); /* kfree(NULL) is safe */
7092 doms_cur = doms_new;
7093 dattr_cur = dattr_new;
7094 ndoms_cur = ndoms_new;
7096 register_sched_domain_sysctl();
7098 mutex_unlock(&sched_domains_mutex);
7102 * Update cpusets according to cpu_active mask. If cpusets are
7103 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7104 * around partition_sched_domains().
7106 static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
7109 switch (action & ~CPU_TASKS_FROZEN) {
7111 case CPU_DOWN_FAILED:
7112 cpuset_update_active_cpus();
7119 static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
7122 switch (action & ~CPU_TASKS_FROZEN) {
7123 case CPU_DOWN_PREPARE:
7124 cpuset_update_active_cpus();
7131 void __init sched_init_smp(void)
7133 cpumask_var_t non_isolated_cpus;
7135 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
7136 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
7141 mutex_lock(&sched_domains_mutex);
7142 init_sched_domains(cpu_active_mask);
7143 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
7144 if (cpumask_empty(non_isolated_cpus))
7145 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
7146 mutex_unlock(&sched_domains_mutex);
7149 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
7150 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
7152 /* RT runtime code needs to handle some hotplug events */
7153 hotcpu_notifier(update_runtime, 0);
7157 /* Move init over to a non-isolated CPU */
7158 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
7160 sched_init_granularity();
7161 free_cpumask_var(non_isolated_cpus);
7163 init_sched_rt_class();
7166 void __init sched_init_smp(void)
7168 sched_init_granularity();
7170 #endif /* CONFIG_SMP */
7172 const_debug unsigned int sysctl_timer_migration = 1;
7174 int in_sched_functions(unsigned long addr)
7176 return in_lock_functions(addr) ||
7177 (addr >= (unsigned long)__sched_text_start
7178 && addr < (unsigned long)__sched_text_end);
7181 #ifdef CONFIG_CGROUP_SCHED
7182 struct task_group root_task_group;
7185 DECLARE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
7187 void __init sched_init(void)
7190 unsigned long alloc_size = 0, ptr;
7192 #ifdef CONFIG_FAIR_GROUP_SCHED
7193 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7195 #ifdef CONFIG_RT_GROUP_SCHED
7196 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7198 #ifdef CONFIG_CPUMASK_OFFSTACK
7199 alloc_size += num_possible_cpus() * cpumask_size();
7202 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
7204 #ifdef CONFIG_FAIR_GROUP_SCHED
7205 root_task_group.se = (struct sched_entity **)ptr;
7206 ptr += nr_cpu_ids * sizeof(void **);
7208 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
7209 ptr += nr_cpu_ids * sizeof(void **);
7211 #endif /* CONFIG_FAIR_GROUP_SCHED */
7212 #ifdef CONFIG_RT_GROUP_SCHED
7213 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
7214 ptr += nr_cpu_ids * sizeof(void **);
7216 root_task_group.rt_rq = (struct rt_rq **)ptr;
7217 ptr += nr_cpu_ids * sizeof(void **);
7219 #endif /* CONFIG_RT_GROUP_SCHED */
7220 #ifdef CONFIG_CPUMASK_OFFSTACK
7221 for_each_possible_cpu(i) {
7222 per_cpu(load_balance_tmpmask, i) = (void *)ptr;
7223 ptr += cpumask_size();
7225 #endif /* CONFIG_CPUMASK_OFFSTACK */
7229 init_defrootdomain();
7232 init_rt_bandwidth(&def_rt_bandwidth,
7233 global_rt_period(), global_rt_runtime());
7235 #ifdef CONFIG_RT_GROUP_SCHED
7236 init_rt_bandwidth(&root_task_group.rt_bandwidth,
7237 global_rt_period(), global_rt_runtime());
7238 #endif /* CONFIG_RT_GROUP_SCHED */
7240 #ifdef CONFIG_CGROUP_SCHED
7241 list_add(&root_task_group.list, &task_groups);
7242 INIT_LIST_HEAD(&root_task_group.children);
7243 INIT_LIST_HEAD(&root_task_group.siblings);
7244 autogroup_init(&init_task);
7246 #endif /* CONFIG_CGROUP_SCHED */
7248 #ifdef CONFIG_CGROUP_CPUACCT
7249 root_cpuacct.cpustat = &kernel_cpustat;
7250 root_cpuacct.cpuusage = alloc_percpu(u64);
7251 /* Too early, not expected to fail */
7252 BUG_ON(!root_cpuacct.cpuusage);
7254 for_each_possible_cpu(i) {
7258 raw_spin_lock_init(&rq->lock);
7260 rq->calc_load_active = 0;
7261 rq->calc_load_update = jiffies + LOAD_FREQ;
7262 init_cfs_rq(&rq->cfs);
7263 init_rt_rq(&rq->rt, rq);
7264 #ifdef CONFIG_FAIR_GROUP_SCHED
7265 root_task_group.shares = ROOT_TASK_GROUP_LOAD;
7266 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
7268 * How much cpu bandwidth does root_task_group get?
7270 * In case of task-groups formed thr' the cgroup filesystem, it
7271 * gets 100% of the cpu resources in the system. This overall
7272 * system cpu resource is divided among the tasks of
7273 * root_task_group and its child task-groups in a fair manner,
7274 * based on each entity's (task or task-group's) weight
7275 * (se->load.weight).
7277 * In other words, if root_task_group has 10 tasks of weight
7278 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7279 * then A0's share of the cpu resource is:
7281 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7283 * We achieve this by letting root_task_group's tasks sit
7284 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7286 init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
7287 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
7288 #endif /* CONFIG_FAIR_GROUP_SCHED */
7290 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
7291 #ifdef CONFIG_RT_GROUP_SCHED
7292 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
7293 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
7296 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
7297 rq->cpu_load[j] = 0;
7299 rq->last_load_update_tick = jiffies;
7304 rq->cpu_power = SCHED_POWER_SCALE;
7305 rq->post_schedule = 0;
7306 rq->active_balance = 0;
7307 rq->next_balance = jiffies;
7312 rq->avg_idle = 2*sysctl_sched_migration_cost;
7314 INIT_LIST_HEAD(&rq->cfs_tasks);
7316 rq_attach_root(rq, &def_root_domain);
7322 atomic_set(&rq->nr_iowait, 0);
7325 set_load_weight(&init_task);
7327 #ifdef CONFIG_PREEMPT_NOTIFIERS
7328 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
7331 #ifdef CONFIG_RT_MUTEXES
7332 plist_head_init(&init_task.pi_waiters);
7336 * The boot idle thread does lazy MMU switching as well:
7338 atomic_inc(&init_mm.mm_count);
7339 enter_lazy_tlb(&init_mm, current);
7342 * Make us the idle thread. Technically, schedule() should not be
7343 * called from this thread, however somewhere below it might be,
7344 * but because we are the idle thread, we just pick up running again
7345 * when this runqueue becomes "idle".
7347 init_idle(current, smp_processor_id());
7349 calc_load_update = jiffies + LOAD_FREQ;
7352 * During early bootup we pretend to be a normal task:
7354 current->sched_class = &fair_sched_class;
7357 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
7358 /* May be allocated at isolcpus cmdline parse time */
7359 if (cpu_isolated_map == NULL)
7360 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
7361 idle_thread_set_boot_cpu();
7363 init_sched_fair_class();
7365 scheduler_running = 1;
7368 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7369 static inline int preempt_count_equals(int preempt_offset)
7371 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
7373 return (nested == preempt_offset);
7376 void __might_sleep(const char *file, int line, int preempt_offset)
7378 static unsigned long prev_jiffy; /* ratelimiting */
7380 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7381 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
7382 system_state != SYSTEM_RUNNING || oops_in_progress)
7384 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
7386 prev_jiffy = jiffies;
7389 "BUG: sleeping function called from invalid context at %s:%d\n",
7392 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7393 in_atomic(), irqs_disabled(),
7394 current->pid, current->comm);
7396 debug_show_held_locks(current);
7397 if (irqs_disabled())
7398 print_irqtrace_events(current);
7401 EXPORT_SYMBOL(__might_sleep);
7404 #ifdef CONFIG_MAGIC_SYSRQ
7405 static void normalize_task(struct rq *rq, struct task_struct *p)
7407 const struct sched_class *prev_class = p->sched_class;
7408 int old_prio = p->prio;
7413 dequeue_task(rq, p, 0);
7414 __setscheduler(rq, p, SCHED_NORMAL, 0);
7416 enqueue_task(rq, p, 0);
7417 resched_task(rq->curr);
7420 check_class_changed(rq, p, prev_class, old_prio);
7423 void normalize_rt_tasks(void)
7425 struct task_struct *g, *p;
7426 unsigned long flags;
7429 read_lock_irqsave(&tasklist_lock, flags);
7430 do_each_thread(g, p) {
7432 * Only normalize user tasks:
7437 p->se.exec_start = 0;
7438 #ifdef CONFIG_SCHEDSTATS
7439 p->se.statistics.wait_start = 0;
7440 p->se.statistics.sleep_start = 0;
7441 p->se.statistics.block_start = 0;
7446 * Renice negative nice level userspace
7449 if (TASK_NICE(p) < 0 && p->mm)
7450 set_user_nice(p, 0);
7454 raw_spin_lock(&p->pi_lock);
7455 rq = __task_rq_lock(p);
7457 normalize_task(rq, p);
7459 __task_rq_unlock(rq);
7460 raw_spin_unlock(&p->pi_lock);
7461 } while_each_thread(g, p);
7463 read_unlock_irqrestore(&tasklist_lock, flags);
7466 #endif /* CONFIG_MAGIC_SYSRQ */
7468 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7470 * These functions are only useful for the IA64 MCA handling, or kdb.
7472 * They can only be called when the whole system has been
7473 * stopped - every CPU needs to be quiescent, and no scheduling
7474 * activity can take place. Using them for anything else would
7475 * be a serious bug, and as a result, they aren't even visible
7476 * under any other configuration.
7480 * curr_task - return the current task for a given cpu.
7481 * @cpu: the processor in question.
7483 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7485 struct task_struct *curr_task(int cpu)
7487 return cpu_curr(cpu);
7490 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7494 * set_curr_task - set the current task for a given cpu.
7495 * @cpu: the processor in question.
7496 * @p: the task pointer to set.
7498 * Description: This function must only be used when non-maskable interrupts
7499 * are serviced on a separate stack. It allows the architecture to switch the
7500 * notion of the current task on a cpu in a non-blocking manner. This function
7501 * must be called with all CPU's synchronized, and interrupts disabled, the
7502 * and caller must save the original value of the current task (see
7503 * curr_task() above) and restore that value before reenabling interrupts and
7504 * re-starting the system.
7506 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7508 void set_curr_task(int cpu, struct task_struct *p)
7515 #ifdef CONFIG_CGROUP_SCHED
7516 /* task_group_lock serializes the addition/removal of task groups */
7517 static DEFINE_SPINLOCK(task_group_lock);
7519 static void free_sched_group(struct task_group *tg)
7521 free_fair_sched_group(tg);
7522 free_rt_sched_group(tg);
7527 /* allocate runqueue etc for a new task group */
7528 struct task_group *sched_create_group(struct task_group *parent)
7530 struct task_group *tg;
7531 unsigned long flags;
7533 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
7535 return ERR_PTR(-ENOMEM);
7537 if (!alloc_fair_sched_group(tg, parent))
7540 if (!alloc_rt_sched_group(tg, parent))
7543 spin_lock_irqsave(&task_group_lock, flags);
7544 list_add_rcu(&tg->list, &task_groups);
7546 WARN_ON(!parent); /* root should already exist */
7548 tg->parent = parent;
7549 INIT_LIST_HEAD(&tg->children);
7550 list_add_rcu(&tg->siblings, &parent->children);
7551 spin_unlock_irqrestore(&task_group_lock, flags);
7556 free_sched_group(tg);
7557 return ERR_PTR(-ENOMEM);
7560 /* rcu callback to free various structures associated with a task group */
7561 static void free_sched_group_rcu(struct rcu_head *rhp)
7563 /* now it should be safe to free those cfs_rqs */
7564 free_sched_group(container_of(rhp, struct task_group, rcu));
7567 /* Destroy runqueue etc associated with a task group */
7568 void sched_destroy_group(struct task_group *tg)
7570 unsigned long flags;
7573 /* end participation in shares distribution */
7574 for_each_possible_cpu(i)
7575 unregister_fair_sched_group(tg, i);
7577 spin_lock_irqsave(&task_group_lock, flags);
7578 list_del_rcu(&tg->list);
7579 list_del_rcu(&tg->siblings);
7580 spin_unlock_irqrestore(&task_group_lock, flags);
7582 /* wait for possible concurrent references to cfs_rqs complete */
7583 call_rcu(&tg->rcu, free_sched_group_rcu);
7586 /* change task's runqueue when it moves between groups.
7587 * The caller of this function should have put the task in its new group
7588 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7589 * reflect its new group.
7591 void sched_move_task(struct task_struct *tsk)
7594 unsigned long flags;
7597 rq = task_rq_lock(tsk, &flags);
7599 running = task_current(rq, tsk);
7603 dequeue_task(rq, tsk, 0);
7604 if (unlikely(running))
7605 tsk->sched_class->put_prev_task(rq, tsk);
7607 #ifdef CONFIG_FAIR_GROUP_SCHED
7608 if (tsk->sched_class->task_move_group)
7609 tsk->sched_class->task_move_group(tsk, on_rq);
7612 set_task_rq(tsk, task_cpu(tsk));
7614 if (unlikely(running))
7615 tsk->sched_class->set_curr_task(rq);
7617 enqueue_task(rq, tsk, 0);
7619 task_rq_unlock(rq, tsk, &flags);
7621 #endif /* CONFIG_CGROUP_SCHED */
7623 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
7624 static unsigned long to_ratio(u64 period, u64 runtime)
7626 if (runtime == RUNTIME_INF)
7629 return div64_u64(runtime << 20, period);
7633 #ifdef CONFIG_RT_GROUP_SCHED
7635 * Ensure that the real time constraints are schedulable.
7637 static DEFINE_MUTEX(rt_constraints_mutex);
7639 /* Must be called with tasklist_lock held */
7640 static inline int tg_has_rt_tasks(struct task_group *tg)
7642 struct task_struct *g, *p;
7644 do_each_thread(g, p) {
7645 if (rt_task(p) && task_rq(p)->rt.tg == tg)
7647 } while_each_thread(g, p);
7652 struct rt_schedulable_data {
7653 struct task_group *tg;
7658 static int tg_rt_schedulable(struct task_group *tg, void *data)
7660 struct rt_schedulable_data *d = data;
7661 struct task_group *child;
7662 unsigned long total, sum = 0;
7663 u64 period, runtime;
7665 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7666 runtime = tg->rt_bandwidth.rt_runtime;
7669 period = d->rt_period;
7670 runtime = d->rt_runtime;
7674 * Cannot have more runtime than the period.
7676 if (runtime > period && runtime != RUNTIME_INF)
7680 * Ensure we don't starve existing RT tasks.
7682 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
7685 total = to_ratio(period, runtime);
7688 * Nobody can have more than the global setting allows.
7690 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
7694 * The sum of our children's runtime should not exceed our own.
7696 list_for_each_entry_rcu(child, &tg->children, siblings) {
7697 period = ktime_to_ns(child->rt_bandwidth.rt_period);
7698 runtime = child->rt_bandwidth.rt_runtime;
7700 if (child == d->tg) {
7701 period = d->rt_period;
7702 runtime = d->rt_runtime;
7705 sum += to_ratio(period, runtime);
7714 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
7718 struct rt_schedulable_data data = {
7720 .rt_period = period,
7721 .rt_runtime = runtime,
7725 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
7731 static int tg_set_rt_bandwidth(struct task_group *tg,
7732 u64 rt_period, u64 rt_runtime)
7736 mutex_lock(&rt_constraints_mutex);
7737 read_lock(&tasklist_lock);
7738 err = __rt_schedulable(tg, rt_period, rt_runtime);
7742 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7743 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
7744 tg->rt_bandwidth.rt_runtime = rt_runtime;
7746 for_each_possible_cpu(i) {
7747 struct rt_rq *rt_rq = tg->rt_rq[i];
7749 raw_spin_lock(&rt_rq->rt_runtime_lock);
7750 rt_rq->rt_runtime = rt_runtime;
7751 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7753 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7755 read_unlock(&tasklist_lock);
7756 mutex_unlock(&rt_constraints_mutex);
7761 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
7763 u64 rt_runtime, rt_period;
7765 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7766 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
7767 if (rt_runtime_us < 0)
7768 rt_runtime = RUNTIME_INF;
7770 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7773 long sched_group_rt_runtime(struct task_group *tg)
7777 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
7780 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
7781 do_div(rt_runtime_us, NSEC_PER_USEC);
7782 return rt_runtime_us;
7785 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
7787 u64 rt_runtime, rt_period;
7789 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
7790 rt_runtime = tg->rt_bandwidth.rt_runtime;
7795 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7798 long sched_group_rt_period(struct task_group *tg)
7802 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
7803 do_div(rt_period_us, NSEC_PER_USEC);
7804 return rt_period_us;
7807 static int sched_rt_global_constraints(void)
7809 u64 runtime, period;
7812 if (sysctl_sched_rt_period <= 0)
7815 runtime = global_rt_runtime();
7816 period = global_rt_period();
7819 * Sanity check on the sysctl variables.
7821 if (runtime > period && runtime != RUNTIME_INF)
7824 mutex_lock(&rt_constraints_mutex);
7825 read_lock(&tasklist_lock);
7826 ret = __rt_schedulable(NULL, 0, 0);
7827 read_unlock(&tasklist_lock);
7828 mutex_unlock(&rt_constraints_mutex);
7833 int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
7835 /* Don't accept realtime tasks when there is no way for them to run */
7836 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
7842 #else /* !CONFIG_RT_GROUP_SCHED */
7843 static int sched_rt_global_constraints(void)
7845 unsigned long flags;
7848 if (sysctl_sched_rt_period <= 0)
7852 * There's always some RT tasks in the root group
7853 * -- migration, kstopmachine etc..
7855 if (sysctl_sched_rt_runtime == 0)
7858 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
7859 for_each_possible_cpu(i) {
7860 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
7862 raw_spin_lock(&rt_rq->rt_runtime_lock);
7863 rt_rq->rt_runtime = global_rt_runtime();
7864 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7866 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
7870 #endif /* CONFIG_RT_GROUP_SCHED */
7872 int sched_rt_handler(struct ctl_table *table, int write,
7873 void __user *buffer, size_t *lenp,
7877 int old_period, old_runtime;
7878 static DEFINE_MUTEX(mutex);
7881 old_period = sysctl_sched_rt_period;
7882 old_runtime = sysctl_sched_rt_runtime;
7884 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7886 if (!ret && write) {
7887 ret = sched_rt_global_constraints();
7889 sysctl_sched_rt_period = old_period;
7890 sysctl_sched_rt_runtime = old_runtime;
7892 def_rt_bandwidth.rt_runtime = global_rt_runtime();
7893 def_rt_bandwidth.rt_period =
7894 ns_to_ktime(global_rt_period());
7897 mutex_unlock(&mutex);
7902 #ifdef CONFIG_CGROUP_SCHED
7904 /* return corresponding task_group object of a cgroup */
7905 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
7907 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
7908 struct task_group, css);
7911 static struct cgroup_subsys_state *cpu_cgroup_create(struct cgroup *cgrp)
7913 struct task_group *tg, *parent;
7915 if (!cgrp->parent) {
7916 /* This is early initialization for the top cgroup */
7917 return &root_task_group.css;
7920 parent = cgroup_tg(cgrp->parent);
7921 tg = sched_create_group(parent);
7923 return ERR_PTR(-ENOMEM);
7928 static void cpu_cgroup_destroy(struct cgroup *cgrp)
7930 struct task_group *tg = cgroup_tg(cgrp);
7932 sched_destroy_group(tg);
7935 static int cpu_cgroup_can_attach(struct cgroup *cgrp,
7936 struct cgroup_taskset *tset)
7938 struct task_struct *task;
7940 cgroup_taskset_for_each(task, cgrp, tset) {
7941 #ifdef CONFIG_RT_GROUP_SCHED
7942 if (!sched_rt_can_attach(cgroup_tg(cgrp), task))
7945 /* We don't support RT-tasks being in separate groups */
7946 if (task->sched_class != &fair_sched_class)
7953 static void cpu_cgroup_attach(struct cgroup *cgrp,
7954 struct cgroup_taskset *tset)
7956 struct task_struct *task;
7958 cgroup_taskset_for_each(task, cgrp, tset)
7959 sched_move_task(task);
7963 cpu_cgroup_exit(struct cgroup *cgrp, struct cgroup *old_cgrp,
7964 struct task_struct *task)
7967 * cgroup_exit() is called in the copy_process() failure path.
7968 * Ignore this case since the task hasn't ran yet, this avoids
7969 * trying to poke a half freed task state from generic code.
7971 if (!(task->flags & PF_EXITING))
7974 sched_move_task(task);
7977 #ifdef CONFIG_FAIR_GROUP_SCHED
7978 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
7981 return sched_group_set_shares(cgroup_tg(cgrp), scale_load(shareval));
7984 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
7986 struct task_group *tg = cgroup_tg(cgrp);
7988 return (u64) scale_load_down(tg->shares);
7991 #ifdef CONFIG_CFS_BANDWIDTH
7992 static DEFINE_MUTEX(cfs_constraints_mutex);
7994 const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
7995 const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
7997 static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
7999 static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
8001 int i, ret = 0, runtime_enabled, runtime_was_enabled;
8002 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8004 if (tg == &root_task_group)
8008 * Ensure we have at some amount of bandwidth every period. This is
8009 * to prevent reaching a state of large arrears when throttled via
8010 * entity_tick() resulting in prolonged exit starvation.
8012 if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
8016 * Likewise, bound things on the otherside by preventing insane quota
8017 * periods. This also allows us to normalize in computing quota
8020 if (period > max_cfs_quota_period)
8023 mutex_lock(&cfs_constraints_mutex);
8024 ret = __cfs_schedulable(tg, period, quota);
8028 runtime_enabled = quota != RUNTIME_INF;
8029 runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
8030 account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled);
8031 raw_spin_lock_irq(&cfs_b->lock);
8032 cfs_b->period = ns_to_ktime(period);
8033 cfs_b->quota = quota;
8035 __refill_cfs_bandwidth_runtime(cfs_b);
8036 /* restart the period timer (if active) to handle new period expiry */
8037 if (runtime_enabled && cfs_b->timer_active) {
8038 /* force a reprogram */
8039 cfs_b->timer_active = 0;
8040 __start_cfs_bandwidth(cfs_b);
8042 raw_spin_unlock_irq(&cfs_b->lock);
8044 for_each_possible_cpu(i) {
8045 struct cfs_rq *cfs_rq = tg->cfs_rq[i];
8046 struct rq *rq = cfs_rq->rq;
8048 raw_spin_lock_irq(&rq->lock);
8049 cfs_rq->runtime_enabled = runtime_enabled;
8050 cfs_rq->runtime_remaining = 0;
8052 if (cfs_rq->throttled)
8053 unthrottle_cfs_rq(cfs_rq);
8054 raw_spin_unlock_irq(&rq->lock);
8057 mutex_unlock(&cfs_constraints_mutex);
8062 int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
8066 period = ktime_to_ns(tg->cfs_bandwidth.period);
8067 if (cfs_quota_us < 0)
8068 quota = RUNTIME_INF;
8070 quota = (u64)cfs_quota_us * NSEC_PER_USEC;
8072 return tg_set_cfs_bandwidth(tg, period, quota);
8075 long tg_get_cfs_quota(struct task_group *tg)
8079 if (tg->cfs_bandwidth.quota == RUNTIME_INF)
8082 quota_us = tg->cfs_bandwidth.quota;
8083 do_div(quota_us, NSEC_PER_USEC);
8088 int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
8092 period = (u64)cfs_period_us * NSEC_PER_USEC;
8093 quota = tg->cfs_bandwidth.quota;
8095 return tg_set_cfs_bandwidth(tg, period, quota);
8098 long tg_get_cfs_period(struct task_group *tg)
8102 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
8103 do_div(cfs_period_us, NSEC_PER_USEC);
8105 return cfs_period_us;
8108 static s64 cpu_cfs_quota_read_s64(struct cgroup *cgrp, struct cftype *cft)
8110 return tg_get_cfs_quota(cgroup_tg(cgrp));
8113 static int cpu_cfs_quota_write_s64(struct cgroup *cgrp, struct cftype *cftype,
8116 return tg_set_cfs_quota(cgroup_tg(cgrp), cfs_quota_us);
8119 static u64 cpu_cfs_period_read_u64(struct cgroup *cgrp, struct cftype *cft)
8121 return tg_get_cfs_period(cgroup_tg(cgrp));
8124 static int cpu_cfs_period_write_u64(struct cgroup *cgrp, struct cftype *cftype,
8127 return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us);
8130 struct cfs_schedulable_data {
8131 struct task_group *tg;
8136 * normalize group quota/period to be quota/max_period
8137 * note: units are usecs
8139 static u64 normalize_cfs_quota(struct task_group *tg,
8140 struct cfs_schedulable_data *d)
8148 period = tg_get_cfs_period(tg);
8149 quota = tg_get_cfs_quota(tg);
8152 /* note: these should typically be equivalent */
8153 if (quota == RUNTIME_INF || quota == -1)
8156 return to_ratio(period, quota);
8159 static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
8161 struct cfs_schedulable_data *d = data;
8162 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8163 s64 quota = 0, parent_quota = -1;
8166 quota = RUNTIME_INF;
8168 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
8170 quota = normalize_cfs_quota(tg, d);
8171 parent_quota = parent_b->hierarchal_quota;
8174 * ensure max(child_quota) <= parent_quota, inherit when no
8177 if (quota == RUNTIME_INF)
8178 quota = parent_quota;
8179 else if (parent_quota != RUNTIME_INF && quota > parent_quota)
8182 cfs_b->hierarchal_quota = quota;
8187 static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
8190 struct cfs_schedulable_data data = {
8196 if (quota != RUNTIME_INF) {
8197 do_div(data.period, NSEC_PER_USEC);
8198 do_div(data.quota, NSEC_PER_USEC);
8202 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
8208 static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft,
8209 struct cgroup_map_cb *cb)
8211 struct task_group *tg = cgroup_tg(cgrp);
8212 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8214 cb->fill(cb, "nr_periods", cfs_b->nr_periods);
8215 cb->fill(cb, "nr_throttled", cfs_b->nr_throttled);
8216 cb->fill(cb, "throttled_time", cfs_b->throttled_time);
8220 #endif /* CONFIG_CFS_BANDWIDTH */
8221 #endif /* CONFIG_FAIR_GROUP_SCHED */
8223 #ifdef CONFIG_RT_GROUP_SCHED
8224 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
8227 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
8230 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
8232 return sched_group_rt_runtime(cgroup_tg(cgrp));
8235 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
8238 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
8241 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
8243 return sched_group_rt_period(cgroup_tg(cgrp));
8245 #endif /* CONFIG_RT_GROUP_SCHED */
8247 static struct cftype cpu_files[] = {
8248 #ifdef CONFIG_FAIR_GROUP_SCHED
8251 .read_u64 = cpu_shares_read_u64,
8252 .write_u64 = cpu_shares_write_u64,
8255 #ifdef CONFIG_CFS_BANDWIDTH
8257 .name = "cfs_quota_us",
8258 .read_s64 = cpu_cfs_quota_read_s64,
8259 .write_s64 = cpu_cfs_quota_write_s64,
8262 .name = "cfs_period_us",
8263 .read_u64 = cpu_cfs_period_read_u64,
8264 .write_u64 = cpu_cfs_period_write_u64,
8268 .read_map = cpu_stats_show,
8271 #ifdef CONFIG_RT_GROUP_SCHED
8273 .name = "rt_runtime_us",
8274 .read_s64 = cpu_rt_runtime_read,
8275 .write_s64 = cpu_rt_runtime_write,
8278 .name = "rt_period_us",
8279 .read_u64 = cpu_rt_period_read_uint,
8280 .write_u64 = cpu_rt_period_write_uint,
8286 struct cgroup_subsys cpu_cgroup_subsys = {
8288 .create = cpu_cgroup_create,
8289 .destroy = cpu_cgroup_destroy,
8290 .can_attach = cpu_cgroup_can_attach,
8291 .attach = cpu_cgroup_attach,
8292 .exit = cpu_cgroup_exit,
8293 .subsys_id = cpu_cgroup_subsys_id,
8294 .base_cftypes = cpu_files,
8298 #endif /* CONFIG_CGROUP_SCHED */
8300 #ifdef CONFIG_CGROUP_CPUACCT
8303 * CPU accounting code for task groups.
8305 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8306 * (balbir@in.ibm.com).
8309 /* create a new cpu accounting group */
8310 static struct cgroup_subsys_state *cpuacct_create(struct cgroup *cgrp)
8315 return &root_cpuacct.css;
8317 ca = kzalloc(sizeof(*ca), GFP_KERNEL);
8321 ca->cpuusage = alloc_percpu(u64);
8325 ca->cpustat = alloc_percpu(struct kernel_cpustat);
8327 goto out_free_cpuusage;
8332 free_percpu(ca->cpuusage);
8336 return ERR_PTR(-ENOMEM);
8339 /* destroy an existing cpu accounting group */
8340 static void cpuacct_destroy(struct cgroup *cgrp)
8342 struct cpuacct *ca = cgroup_ca(cgrp);
8344 free_percpu(ca->cpustat);
8345 free_percpu(ca->cpuusage);
8349 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
8351 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8354 #ifndef CONFIG_64BIT
8356 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
8358 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8360 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8368 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
8370 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8372 #ifndef CONFIG_64BIT
8374 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8376 raw_spin_lock_irq(&cpu_rq(cpu)->lock);
8378 raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
8384 /* return total cpu usage (in nanoseconds) of a group */
8385 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
8387 struct cpuacct *ca = cgroup_ca(cgrp);
8388 u64 totalcpuusage = 0;
8391 for_each_present_cpu(i)
8392 totalcpuusage += cpuacct_cpuusage_read(ca, i);
8394 return totalcpuusage;
8397 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
8400 struct cpuacct *ca = cgroup_ca(cgrp);
8409 for_each_present_cpu(i)
8410 cpuacct_cpuusage_write(ca, i, 0);
8416 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
8419 struct cpuacct *ca = cgroup_ca(cgroup);
8423 for_each_present_cpu(i) {
8424 percpu = cpuacct_cpuusage_read(ca, i);
8425 seq_printf(m, "%llu ", (unsigned long long) percpu);
8427 seq_printf(m, "\n");
8431 static const char *cpuacct_stat_desc[] = {
8432 [CPUACCT_STAT_USER] = "user",
8433 [CPUACCT_STAT_SYSTEM] = "system",
8436 static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
8437 struct cgroup_map_cb *cb)
8439 struct cpuacct *ca = cgroup_ca(cgrp);
8443 for_each_online_cpu(cpu) {
8444 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
8445 val += kcpustat->cpustat[CPUTIME_USER];
8446 val += kcpustat->cpustat[CPUTIME_NICE];
8448 val = cputime64_to_clock_t(val);
8449 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_USER], val);
8452 for_each_online_cpu(cpu) {
8453 struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
8454 val += kcpustat->cpustat[CPUTIME_SYSTEM];
8455 val += kcpustat->cpustat[CPUTIME_IRQ];
8456 val += kcpustat->cpustat[CPUTIME_SOFTIRQ];
8459 val = cputime64_to_clock_t(val);
8460 cb->fill(cb, cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val);
8465 static struct cftype files[] = {
8468 .read_u64 = cpuusage_read,
8469 .write_u64 = cpuusage_write,
8472 .name = "usage_percpu",
8473 .read_seq_string = cpuacct_percpu_seq_read,
8477 .read_map = cpuacct_stats_show,
8483 * charge this task's execution time to its accounting group.
8485 * called with rq->lock held.
8487 void cpuacct_charge(struct task_struct *tsk, u64 cputime)
8492 if (unlikely(!cpuacct_subsys.active))
8495 cpu = task_cpu(tsk);
8501 for (; ca; ca = parent_ca(ca)) {
8502 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
8503 *cpuusage += cputime;
8509 struct cgroup_subsys cpuacct_subsys = {
8511 .create = cpuacct_create,
8512 .destroy = cpuacct_destroy,
8513 .subsys_id = cpuacct_subsys_id,
8514 .base_cftypes = files,
8516 #endif /* CONFIG_CGROUP_CPUACCT */