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>
75 #include <linux/context_tracking.h>
76 #include <linux/compiler.h>
78 #include <asm/switch_to.h>
80 #include <asm/irq_regs.h>
81 #include <asm/mutex.h>
82 #ifdef CONFIG_PARAVIRT
83 #include <asm/paravirt.h>
87 #include "../workqueue_internal.h"
88 #include "../smpboot.h"
90 #define CREATE_TRACE_POINTS
91 #include <trace/events/sched.h>
93 void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period)
96 ktime_t soft, hard, now;
99 if (hrtimer_active(period_timer))
102 now = hrtimer_cb_get_time(period_timer);
103 hrtimer_forward(period_timer, now, period);
105 soft = hrtimer_get_softexpires(period_timer);
106 hard = hrtimer_get_expires(period_timer);
107 delta = ktime_to_ns(ktime_sub(hard, soft));
108 __hrtimer_start_range_ns(period_timer, soft, delta,
109 HRTIMER_MODE_ABS_PINNED, 0);
113 DEFINE_MUTEX(sched_domains_mutex);
114 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
116 static void update_rq_clock_task(struct rq *rq, s64 delta);
118 void update_rq_clock(struct rq *rq)
122 if (rq->skip_clock_update > 0)
125 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
129 update_rq_clock_task(rq, delta);
133 * Debugging: various feature bits
136 #define SCHED_FEAT(name, enabled) \
137 (1UL << __SCHED_FEAT_##name) * enabled |
139 const_debug unsigned int sysctl_sched_features =
140 #include "features.h"
145 #ifdef CONFIG_SCHED_DEBUG
146 #define SCHED_FEAT(name, enabled) \
149 static const char * const sched_feat_names[] = {
150 #include "features.h"
155 static int sched_feat_show(struct seq_file *m, void *v)
159 for (i = 0; i < __SCHED_FEAT_NR; i++) {
160 if (!(sysctl_sched_features & (1UL << i)))
162 seq_printf(m, "%s ", sched_feat_names[i]);
169 #ifdef HAVE_JUMP_LABEL
171 #define jump_label_key__true STATIC_KEY_INIT_TRUE
172 #define jump_label_key__false STATIC_KEY_INIT_FALSE
174 #define SCHED_FEAT(name, enabled) \
175 jump_label_key__##enabled ,
177 struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
178 #include "features.h"
183 static void sched_feat_disable(int i)
185 if (static_key_enabled(&sched_feat_keys[i]))
186 static_key_slow_dec(&sched_feat_keys[i]);
189 static void sched_feat_enable(int i)
191 if (!static_key_enabled(&sched_feat_keys[i]))
192 static_key_slow_inc(&sched_feat_keys[i]);
195 static void sched_feat_disable(int i) { };
196 static void sched_feat_enable(int i) { };
197 #endif /* HAVE_JUMP_LABEL */
199 static int sched_feat_set(char *cmp)
204 if (strncmp(cmp, "NO_", 3) == 0) {
209 for (i = 0; i < __SCHED_FEAT_NR; i++) {
210 if (strcmp(cmp, sched_feat_names[i]) == 0) {
212 sysctl_sched_features &= ~(1UL << i);
213 sched_feat_disable(i);
215 sysctl_sched_features |= (1UL << i);
216 sched_feat_enable(i);
226 sched_feat_write(struct file *filp, const char __user *ubuf,
227 size_t cnt, loff_t *ppos)
237 if (copy_from_user(&buf, ubuf, cnt))
243 /* Ensure the static_key remains in a consistent state */
244 inode = file_inode(filp);
245 mutex_lock(&inode->i_mutex);
246 i = sched_feat_set(cmp);
247 mutex_unlock(&inode->i_mutex);
248 if (i == __SCHED_FEAT_NR)
256 static int sched_feat_open(struct inode *inode, struct file *filp)
258 return single_open(filp, sched_feat_show, NULL);
261 static const struct file_operations sched_feat_fops = {
262 .open = sched_feat_open,
263 .write = sched_feat_write,
266 .release = single_release,
269 static __init int sched_init_debug(void)
271 debugfs_create_file("sched_features", 0644, NULL, NULL,
276 late_initcall(sched_init_debug);
277 #endif /* CONFIG_SCHED_DEBUG */
280 * Number of tasks to iterate in a single balance run.
281 * Limited because this is done with IRQs disabled.
283 const_debug unsigned int sysctl_sched_nr_migrate = 32;
286 * period over which we average the RT time consumption, measured
291 const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC;
294 * period over which we measure -rt task cpu usage in us.
297 unsigned int sysctl_sched_rt_period = 1000000;
299 __read_mostly int scheduler_running;
302 * part of the period that we allow rt tasks to run in us.
305 int sysctl_sched_rt_runtime = 950000;
308 * __task_rq_lock - lock the rq @p resides on.
310 static inline struct rq *__task_rq_lock(struct task_struct *p)
315 lockdep_assert_held(&p->pi_lock);
319 raw_spin_lock(&rq->lock);
320 if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
322 raw_spin_unlock(&rq->lock);
324 while (unlikely(task_on_rq_migrating(p)))
330 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
332 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
333 __acquires(p->pi_lock)
339 raw_spin_lock_irqsave(&p->pi_lock, *flags);
341 raw_spin_lock(&rq->lock);
342 if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
344 raw_spin_unlock(&rq->lock);
345 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
347 while (unlikely(task_on_rq_migrating(p)))
352 static void __task_rq_unlock(struct rq *rq)
355 raw_spin_unlock(&rq->lock);
359 task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
361 __releases(p->pi_lock)
363 raw_spin_unlock(&rq->lock);
364 raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
368 * this_rq_lock - lock this runqueue and disable interrupts.
370 static struct rq *this_rq_lock(void)
377 raw_spin_lock(&rq->lock);
382 #ifdef CONFIG_SCHED_HRTICK
384 * Use HR-timers to deliver accurate preemption points.
387 static void hrtick_clear(struct rq *rq)
389 if (hrtimer_active(&rq->hrtick_timer))
390 hrtimer_cancel(&rq->hrtick_timer);
394 * High-resolution timer tick.
395 * Runs from hardirq context with interrupts disabled.
397 static enum hrtimer_restart hrtick(struct hrtimer *timer)
399 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
401 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
403 raw_spin_lock(&rq->lock);
405 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
406 raw_spin_unlock(&rq->lock);
408 return HRTIMER_NORESTART;
413 static int __hrtick_restart(struct rq *rq)
415 struct hrtimer *timer = &rq->hrtick_timer;
416 ktime_t time = hrtimer_get_softexpires(timer);
418 return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0);
422 * called from hardirq (IPI) context
424 static void __hrtick_start(void *arg)
428 raw_spin_lock(&rq->lock);
429 __hrtick_restart(rq);
430 rq->hrtick_csd_pending = 0;
431 raw_spin_unlock(&rq->lock);
435 * Called to set the hrtick timer state.
437 * called with rq->lock held and irqs disabled
439 void hrtick_start(struct rq *rq, u64 delay)
441 struct hrtimer *timer = &rq->hrtick_timer;
446 * Don't schedule slices shorter than 10000ns, that just
447 * doesn't make sense and can cause timer DoS.
449 delta = max_t(s64, delay, 10000LL);
450 time = ktime_add_ns(timer->base->get_time(), delta);
452 hrtimer_set_expires(timer, time);
454 if (rq == this_rq()) {
455 __hrtick_restart(rq);
456 } else if (!rq->hrtick_csd_pending) {
457 smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
458 rq->hrtick_csd_pending = 1;
463 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
465 int cpu = (int)(long)hcpu;
468 case CPU_UP_CANCELED:
469 case CPU_UP_CANCELED_FROZEN:
470 case CPU_DOWN_PREPARE:
471 case CPU_DOWN_PREPARE_FROZEN:
473 case CPU_DEAD_FROZEN:
474 hrtick_clear(cpu_rq(cpu));
481 static __init void init_hrtick(void)
483 hotcpu_notifier(hotplug_hrtick, 0);
487 * Called to set the hrtick timer state.
489 * called with rq->lock held and irqs disabled
491 void hrtick_start(struct rq *rq, u64 delay)
493 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
494 HRTIMER_MODE_REL_PINNED, 0);
497 static inline void init_hrtick(void)
500 #endif /* CONFIG_SMP */
502 static void init_rq_hrtick(struct rq *rq)
505 rq->hrtick_csd_pending = 0;
507 rq->hrtick_csd.flags = 0;
508 rq->hrtick_csd.func = __hrtick_start;
509 rq->hrtick_csd.info = rq;
512 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
513 rq->hrtick_timer.function = hrtick;
515 #else /* CONFIG_SCHED_HRTICK */
516 static inline void hrtick_clear(struct rq *rq)
520 static inline void init_rq_hrtick(struct rq *rq)
524 static inline void init_hrtick(void)
527 #endif /* CONFIG_SCHED_HRTICK */
530 * cmpxchg based fetch_or, macro so it works for different integer types
532 #define fetch_or(ptr, val) \
533 ({ typeof(*(ptr)) __old, __val = *(ptr); \
535 __old = cmpxchg((ptr), __val, __val | (val)); \
536 if (__old == __val) \
543 #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
545 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
546 * this avoids any races wrt polling state changes and thereby avoids
549 static bool set_nr_and_not_polling(struct task_struct *p)
551 struct thread_info *ti = task_thread_info(p);
552 return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
556 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
558 * If this returns true, then the idle task promises to call
559 * sched_ttwu_pending() and reschedule soon.
561 static bool set_nr_if_polling(struct task_struct *p)
563 struct thread_info *ti = task_thread_info(p);
564 typeof(ti->flags) old, val = ACCESS_ONCE(ti->flags);
567 if (!(val & _TIF_POLLING_NRFLAG))
569 if (val & _TIF_NEED_RESCHED)
571 old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED);
580 static bool set_nr_and_not_polling(struct task_struct *p)
582 set_tsk_need_resched(p);
587 static bool set_nr_if_polling(struct task_struct *p)
595 * resched_curr - mark rq's current task 'to be rescheduled now'.
597 * On UP this means the setting of the need_resched flag, on SMP it
598 * might also involve a cross-CPU call to trigger the scheduler on
601 void resched_curr(struct rq *rq)
603 struct task_struct *curr = rq->curr;
606 lockdep_assert_held(&rq->lock);
608 if (test_tsk_need_resched(curr))
613 if (cpu == smp_processor_id()) {
614 set_tsk_need_resched(curr);
615 set_preempt_need_resched();
619 if (set_nr_and_not_polling(curr))
620 smp_send_reschedule(cpu);
622 trace_sched_wake_idle_without_ipi(cpu);
625 void resched_cpu(int cpu)
627 struct rq *rq = cpu_rq(cpu);
630 if (!raw_spin_trylock_irqsave(&rq->lock, flags))
633 raw_spin_unlock_irqrestore(&rq->lock, flags);
637 #ifdef CONFIG_NO_HZ_COMMON
639 * In the semi idle case, use the nearest busy cpu for migrating timers
640 * from an idle cpu. This is good for power-savings.
642 * We don't do similar optimization for completely idle system, as
643 * selecting an idle cpu will add more delays to the timers than intended
644 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
646 int get_nohz_timer_target(int pinned)
648 int cpu = smp_processor_id();
650 struct sched_domain *sd;
652 if (pinned || !get_sysctl_timer_migration() || !idle_cpu(cpu))
656 for_each_domain(cpu, sd) {
657 for_each_cpu(i, sched_domain_span(sd)) {
669 * When add_timer_on() enqueues a timer into the timer wheel of an
670 * idle CPU then this timer might expire before the next timer event
671 * which is scheduled to wake up that CPU. In case of a completely
672 * idle system the next event might even be infinite time into the
673 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
674 * leaves the inner idle loop so the newly added timer is taken into
675 * account when the CPU goes back to idle and evaluates the timer
676 * wheel for the next timer event.
678 static void wake_up_idle_cpu(int cpu)
680 struct rq *rq = cpu_rq(cpu);
682 if (cpu == smp_processor_id())
685 if (set_nr_and_not_polling(rq->idle))
686 smp_send_reschedule(cpu);
688 trace_sched_wake_idle_without_ipi(cpu);
691 static bool wake_up_full_nohz_cpu(int cpu)
694 * We just need the target to call irq_exit() and re-evaluate
695 * the next tick. The nohz full kick at least implies that.
696 * If needed we can still optimize that later with an
699 if (tick_nohz_full_cpu(cpu)) {
700 if (cpu != smp_processor_id() ||
701 tick_nohz_tick_stopped())
702 tick_nohz_full_kick_cpu(cpu);
709 void wake_up_nohz_cpu(int cpu)
711 if (!wake_up_full_nohz_cpu(cpu))
712 wake_up_idle_cpu(cpu);
715 static inline bool got_nohz_idle_kick(void)
717 int cpu = smp_processor_id();
719 if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)))
722 if (idle_cpu(cpu) && !need_resched())
726 * We can't run Idle Load Balance on this CPU for this time so we
727 * cancel it and clear NOHZ_BALANCE_KICK
729 clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu));
733 #else /* CONFIG_NO_HZ_COMMON */
735 static inline bool got_nohz_idle_kick(void)
740 #endif /* CONFIG_NO_HZ_COMMON */
742 #ifdef CONFIG_NO_HZ_FULL
743 bool sched_can_stop_tick(void)
746 * More than one running task need preemption.
747 * nr_running update is assumed to be visible
748 * after IPI is sent from wakers.
750 if (this_rq()->nr_running > 1)
755 #endif /* CONFIG_NO_HZ_FULL */
757 void sched_avg_update(struct rq *rq)
759 s64 period = sched_avg_period();
761 while ((s64)(rq_clock(rq) - rq->age_stamp) > period) {
763 * Inline assembly required to prevent the compiler
764 * optimising this loop into a divmod call.
765 * See __iter_div_u64_rem() for another example of this.
767 asm("" : "+rm" (rq->age_stamp));
768 rq->age_stamp += period;
773 #endif /* CONFIG_SMP */
775 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
776 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
778 * Iterate task_group tree rooted at *from, calling @down when first entering a
779 * node and @up when leaving it for the final time.
781 * Caller must hold rcu_lock or sufficient equivalent.
783 int walk_tg_tree_from(struct task_group *from,
784 tg_visitor down, tg_visitor up, void *data)
786 struct task_group *parent, *child;
792 ret = (*down)(parent, data);
795 list_for_each_entry_rcu(child, &parent->children, siblings) {
802 ret = (*up)(parent, data);
803 if (ret || parent == from)
807 parent = parent->parent;
814 int tg_nop(struct task_group *tg, void *data)
820 static void set_load_weight(struct task_struct *p)
822 int prio = p->static_prio - MAX_RT_PRIO;
823 struct load_weight *load = &p->se.load;
826 * SCHED_IDLE tasks get minimal weight:
828 if (p->policy == SCHED_IDLE) {
829 load->weight = scale_load(WEIGHT_IDLEPRIO);
830 load->inv_weight = WMULT_IDLEPRIO;
834 load->weight = scale_load(prio_to_weight[prio]);
835 load->inv_weight = prio_to_wmult[prio];
838 static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
841 sched_info_queued(rq, p);
842 p->sched_class->enqueue_task(rq, p, flags);
845 static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
848 sched_info_dequeued(rq, p);
849 p->sched_class->dequeue_task(rq, p, flags);
852 void activate_task(struct rq *rq, struct task_struct *p, int flags)
854 if (task_contributes_to_load(p))
855 rq->nr_uninterruptible--;
857 enqueue_task(rq, p, flags);
860 void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
862 if (task_contributes_to_load(p))
863 rq->nr_uninterruptible++;
865 dequeue_task(rq, p, flags);
868 static void update_rq_clock_task(struct rq *rq, s64 delta)
871 * In theory, the compile should just see 0 here, and optimize out the call
872 * to sched_rt_avg_update. But I don't trust it...
874 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
875 s64 steal = 0, irq_delta = 0;
877 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
878 irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
881 * Since irq_time is only updated on {soft,}irq_exit, we might run into
882 * this case when a previous update_rq_clock() happened inside a
885 * When this happens, we stop ->clock_task and only update the
886 * prev_irq_time stamp to account for the part that fit, so that a next
887 * update will consume the rest. This ensures ->clock_task is
890 * It does however cause some slight miss-attribution of {soft,}irq
891 * time, a more accurate solution would be to update the irq_time using
892 * the current rq->clock timestamp, except that would require using
895 if (irq_delta > delta)
898 rq->prev_irq_time += irq_delta;
901 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
902 if (static_key_false((¶virt_steal_rq_enabled))) {
903 steal = paravirt_steal_clock(cpu_of(rq));
904 steal -= rq->prev_steal_time_rq;
906 if (unlikely(steal > delta))
909 rq->prev_steal_time_rq += steal;
914 rq->clock_task += delta;
916 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
917 if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY))
918 sched_rt_avg_update(rq, irq_delta + steal);
922 void sched_set_stop_task(int cpu, struct task_struct *stop)
924 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
925 struct task_struct *old_stop = cpu_rq(cpu)->stop;
929 * Make it appear like a SCHED_FIFO task, its something
930 * userspace knows about and won't get confused about.
932 * Also, it will make PI more or less work without too
933 * much confusion -- but then, stop work should not
934 * rely on PI working anyway.
936 sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m);
938 stop->sched_class = &stop_sched_class;
941 cpu_rq(cpu)->stop = stop;
945 * Reset it back to a normal scheduling class so that
946 * it can die in pieces.
948 old_stop->sched_class = &rt_sched_class;
953 * __normal_prio - return the priority that is based on the static prio
955 static inline int __normal_prio(struct task_struct *p)
957 return p->static_prio;
961 * Calculate the expected normal priority: i.e. priority
962 * without taking RT-inheritance into account. Might be
963 * boosted by interactivity modifiers. Changes upon fork,
964 * setprio syscalls, and whenever the interactivity
965 * estimator recalculates.
967 static inline int normal_prio(struct task_struct *p)
971 if (task_has_dl_policy(p))
972 prio = MAX_DL_PRIO-1;
973 else if (task_has_rt_policy(p))
974 prio = MAX_RT_PRIO-1 - p->rt_priority;
976 prio = __normal_prio(p);
981 * Calculate the current priority, i.e. the priority
982 * taken into account by the scheduler. This value might
983 * be boosted by RT tasks, or might be boosted by
984 * interactivity modifiers. Will be RT if the task got
985 * RT-boosted. If not then it returns p->normal_prio.
987 static int effective_prio(struct task_struct *p)
989 p->normal_prio = normal_prio(p);
991 * If we are RT tasks or we were boosted to RT priority,
992 * keep the priority unchanged. Otherwise, update priority
993 * to the normal priority:
995 if (!rt_prio(p->prio))
996 return p->normal_prio;
1001 * task_curr - is this task currently executing on a CPU?
1002 * @p: the task in question.
1004 * Return: 1 if the task is currently executing. 0 otherwise.
1006 inline int task_curr(const struct task_struct *p)
1008 return cpu_curr(task_cpu(p)) == p;
1012 * Can drop rq->lock because from sched_class::switched_from() methods drop it.
1014 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1015 const struct sched_class *prev_class,
1018 if (prev_class != p->sched_class) {
1019 if (prev_class->switched_from)
1020 prev_class->switched_from(rq, p);
1021 /* Possble rq->lock 'hole'. */
1022 p->sched_class->switched_to(rq, p);
1023 } else if (oldprio != p->prio || dl_task(p))
1024 p->sched_class->prio_changed(rq, p, oldprio);
1027 void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
1029 const struct sched_class *class;
1031 if (p->sched_class == rq->curr->sched_class) {
1032 rq->curr->sched_class->check_preempt_curr(rq, p, flags);
1034 for_each_class(class) {
1035 if (class == rq->curr->sched_class)
1037 if (class == p->sched_class) {
1045 * A queue event has occurred, and we're going to schedule. In
1046 * this case, we can save a useless back to back clock update.
1048 if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr))
1049 rq->skip_clock_update = 1;
1053 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1055 #ifdef CONFIG_SCHED_DEBUG
1057 * We should never call set_task_cpu() on a blocked task,
1058 * ttwu() will sort out the placement.
1060 WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
1063 #ifdef CONFIG_LOCKDEP
1065 * The caller should hold either p->pi_lock or rq->lock, when changing
1066 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1068 * sched_move_task() holds both and thus holding either pins the cgroup,
1071 * Furthermore, all task_rq users should acquire both locks, see
1074 WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
1075 lockdep_is_held(&task_rq(p)->lock)));
1079 trace_sched_migrate_task(p, new_cpu);
1081 if (task_cpu(p) != new_cpu) {
1082 if (p->sched_class->migrate_task_rq)
1083 p->sched_class->migrate_task_rq(p, new_cpu);
1084 p->se.nr_migrations++;
1085 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);
1088 __set_task_cpu(p, new_cpu);
1091 static void __migrate_swap_task(struct task_struct *p, int cpu)
1093 if (task_on_rq_queued(p)) {
1094 struct rq *src_rq, *dst_rq;
1096 src_rq = task_rq(p);
1097 dst_rq = cpu_rq(cpu);
1099 deactivate_task(src_rq, p, 0);
1100 set_task_cpu(p, cpu);
1101 activate_task(dst_rq, p, 0);
1102 check_preempt_curr(dst_rq, p, 0);
1105 * Task isn't running anymore; make it appear like we migrated
1106 * it before it went to sleep. This means on wakeup we make the
1107 * previous cpu our targer instead of where it really is.
1113 struct migration_swap_arg {
1114 struct task_struct *src_task, *dst_task;
1115 int src_cpu, dst_cpu;
1118 static int migrate_swap_stop(void *data)
1120 struct migration_swap_arg *arg = data;
1121 struct rq *src_rq, *dst_rq;
1124 src_rq = cpu_rq(arg->src_cpu);
1125 dst_rq = cpu_rq(arg->dst_cpu);
1127 double_raw_lock(&arg->src_task->pi_lock,
1128 &arg->dst_task->pi_lock);
1129 double_rq_lock(src_rq, dst_rq);
1130 if (task_cpu(arg->dst_task) != arg->dst_cpu)
1133 if (task_cpu(arg->src_task) != arg->src_cpu)
1136 if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task)))
1139 if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task)))
1142 __migrate_swap_task(arg->src_task, arg->dst_cpu);
1143 __migrate_swap_task(arg->dst_task, arg->src_cpu);
1148 double_rq_unlock(src_rq, dst_rq);
1149 raw_spin_unlock(&arg->dst_task->pi_lock);
1150 raw_spin_unlock(&arg->src_task->pi_lock);
1156 * Cross migrate two tasks
1158 int migrate_swap(struct task_struct *cur, struct task_struct *p)
1160 struct migration_swap_arg arg;
1163 arg = (struct migration_swap_arg){
1165 .src_cpu = task_cpu(cur),
1167 .dst_cpu = task_cpu(p),
1170 if (arg.src_cpu == arg.dst_cpu)
1174 * These three tests are all lockless; this is OK since all of them
1175 * will be re-checked with proper locks held further down the line.
1177 if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu))
1180 if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task)))
1183 if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task)))
1186 trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu);
1187 ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg);
1193 struct migration_arg {
1194 struct task_struct *task;
1198 static int migration_cpu_stop(void *data);
1201 * wait_task_inactive - wait for a thread to unschedule.
1203 * If @match_state is nonzero, it's the @p->state value just checked and
1204 * not expected to change. If it changes, i.e. @p might have woken up,
1205 * then return zero. When we succeed in waiting for @p to be off its CPU,
1206 * we return a positive number (its total switch count). If a second call
1207 * a short while later returns the same number, the caller can be sure that
1208 * @p has remained unscheduled the whole time.
1210 * The caller must ensure that the task *will* unschedule sometime soon,
1211 * else this function might spin for a *long* time. This function can't
1212 * be called with interrupts off, or it may introduce deadlock with
1213 * smp_call_function() if an IPI is sent by the same process we are
1214 * waiting to become inactive.
1216 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1218 unsigned long flags;
1219 int running, queued;
1225 * We do the initial early heuristics without holding
1226 * any task-queue locks at all. We'll only try to get
1227 * the runqueue lock when things look like they will
1233 * If the task is actively running on another CPU
1234 * still, just relax and busy-wait without holding
1237 * NOTE! Since we don't hold any locks, it's not
1238 * even sure that "rq" stays as the right runqueue!
1239 * But we don't care, since "task_running()" will
1240 * return false if the runqueue has changed and p
1241 * is actually now running somewhere else!
1243 while (task_running(rq, p)) {
1244 if (match_state && unlikely(p->state != match_state))
1250 * Ok, time to look more closely! We need the rq
1251 * lock now, to be *sure*. If we're wrong, we'll
1252 * just go back and repeat.
1254 rq = task_rq_lock(p, &flags);
1255 trace_sched_wait_task(p);
1256 running = task_running(rq, p);
1257 queued = task_on_rq_queued(p);
1259 if (!match_state || p->state == match_state)
1260 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1261 task_rq_unlock(rq, p, &flags);
1264 * If it changed from the expected state, bail out now.
1266 if (unlikely(!ncsw))
1270 * Was it really running after all now that we
1271 * checked with the proper locks actually held?
1273 * Oops. Go back and try again..
1275 if (unlikely(running)) {
1281 * It's not enough that it's not actively running,
1282 * it must be off the runqueue _entirely_, and not
1285 * So if it was still runnable (but just not actively
1286 * running right now), it's preempted, and we should
1287 * yield - it could be a while.
1289 if (unlikely(queued)) {
1290 ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
1292 set_current_state(TASK_UNINTERRUPTIBLE);
1293 schedule_hrtimeout(&to, HRTIMER_MODE_REL);
1298 * Ahh, all good. It wasn't running, and it wasn't
1299 * runnable, which means that it will never become
1300 * running in the future either. We're all done!
1309 * kick_process - kick a running thread to enter/exit the kernel
1310 * @p: the to-be-kicked thread
1312 * Cause a process which is running on another CPU to enter
1313 * kernel-mode, without any delay. (to get signals handled.)
1315 * NOTE: this function doesn't have to take the runqueue lock,
1316 * because all it wants to ensure is that the remote task enters
1317 * the kernel. If the IPI races and the task has been migrated
1318 * to another CPU then no harm is done and the purpose has been
1321 void kick_process(struct task_struct *p)
1327 if ((cpu != smp_processor_id()) && task_curr(p))
1328 smp_send_reschedule(cpu);
1331 EXPORT_SYMBOL_GPL(kick_process);
1332 #endif /* CONFIG_SMP */
1336 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1338 static int select_fallback_rq(int cpu, struct task_struct *p)
1340 int nid = cpu_to_node(cpu);
1341 const struct cpumask *nodemask = NULL;
1342 enum { cpuset, possible, fail } state = cpuset;
1346 * If the node that the cpu is on has been offlined, cpu_to_node()
1347 * will return -1. There is no cpu on the node, and we should
1348 * select the cpu on the other node.
1351 nodemask = cpumask_of_node(nid);
1353 /* Look for allowed, online CPU in same node. */
1354 for_each_cpu(dest_cpu, nodemask) {
1355 if (!cpu_online(dest_cpu))
1357 if (!cpu_active(dest_cpu))
1359 if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
1365 /* Any allowed, online CPU? */
1366 for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) {
1367 if (!cpu_online(dest_cpu))
1369 if (!cpu_active(dest_cpu))
1376 /* No more Mr. Nice Guy. */
1377 cpuset_cpus_allowed_fallback(p);
1382 do_set_cpus_allowed(p, cpu_possible_mask);
1393 if (state != cpuset) {
1395 * Don't tell them about moving exiting tasks or
1396 * kernel threads (both mm NULL), since they never
1399 if (p->mm && printk_ratelimit()) {
1400 printk_deferred("process %d (%s) no longer affine to cpu%d\n",
1401 task_pid_nr(p), p->comm, cpu);
1409 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1412 int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
1414 if (p->nr_cpus_allowed > 1)
1415 cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags);
1418 * In order not to call set_task_cpu() on a blocking task we need
1419 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1422 * Since this is common to all placement strategies, this lives here.
1424 * [ this allows ->select_task() to simply return task_cpu(p) and
1425 * not worry about this generic constraint ]
1427 if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||
1429 cpu = select_fallback_rq(task_cpu(p), p);
1434 static void update_avg(u64 *avg, u64 sample)
1436 s64 diff = sample - *avg;
1442 ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
1444 #ifdef CONFIG_SCHEDSTATS
1445 struct rq *rq = this_rq();
1448 int this_cpu = smp_processor_id();
1450 if (cpu == this_cpu) {
1451 schedstat_inc(rq, ttwu_local);
1452 schedstat_inc(p, se.statistics.nr_wakeups_local);
1454 struct sched_domain *sd;
1456 schedstat_inc(p, se.statistics.nr_wakeups_remote);
1458 for_each_domain(this_cpu, sd) {
1459 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
1460 schedstat_inc(sd, ttwu_wake_remote);
1467 if (wake_flags & WF_MIGRATED)
1468 schedstat_inc(p, se.statistics.nr_wakeups_migrate);
1470 #endif /* CONFIG_SMP */
1472 schedstat_inc(rq, ttwu_count);
1473 schedstat_inc(p, se.statistics.nr_wakeups);
1475 if (wake_flags & WF_SYNC)
1476 schedstat_inc(p, se.statistics.nr_wakeups_sync);
1478 #endif /* CONFIG_SCHEDSTATS */
1481 static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
1483 activate_task(rq, p, en_flags);
1484 p->on_rq = TASK_ON_RQ_QUEUED;
1486 /* if a worker is waking up, notify workqueue */
1487 if (p->flags & PF_WQ_WORKER)
1488 wq_worker_waking_up(p, cpu_of(rq));
1492 * Mark the task runnable and perform wakeup-preemption.
1495 ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
1497 check_preempt_curr(rq, p, wake_flags);
1498 trace_sched_wakeup(p, true);
1500 p->state = TASK_RUNNING;
1502 if (p->sched_class->task_woken)
1503 p->sched_class->task_woken(rq, p);
1505 if (rq->idle_stamp) {
1506 u64 delta = rq_clock(rq) - rq->idle_stamp;
1507 u64 max = 2*rq->max_idle_balance_cost;
1509 update_avg(&rq->avg_idle, delta);
1511 if (rq->avg_idle > max)
1520 ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
1523 if (p->sched_contributes_to_load)
1524 rq->nr_uninterruptible--;
1527 ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING);
1528 ttwu_do_wakeup(rq, p, wake_flags);
1532 * Called in case the task @p isn't fully descheduled from its runqueue,
1533 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1534 * since all we need to do is flip p->state to TASK_RUNNING, since
1535 * the task is still ->on_rq.
1537 static int ttwu_remote(struct task_struct *p, int wake_flags)
1542 rq = __task_rq_lock(p);
1543 if (task_on_rq_queued(p)) {
1544 /* check_preempt_curr() may use rq clock */
1545 update_rq_clock(rq);
1546 ttwu_do_wakeup(rq, p, wake_flags);
1549 __task_rq_unlock(rq);
1555 void sched_ttwu_pending(void)
1557 struct rq *rq = this_rq();
1558 struct llist_node *llist = llist_del_all(&rq->wake_list);
1559 struct task_struct *p;
1560 unsigned long flags;
1565 raw_spin_lock_irqsave(&rq->lock, flags);
1568 p = llist_entry(llist, struct task_struct, wake_entry);
1569 llist = llist_next(llist);
1570 ttwu_do_activate(rq, p, 0);
1573 raw_spin_unlock_irqrestore(&rq->lock, flags);
1576 void scheduler_ipi(void)
1579 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1580 * TIF_NEED_RESCHED remotely (for the first time) will also send
1583 preempt_fold_need_resched();
1585 if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick())
1589 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1590 * traditionally all their work was done from the interrupt return
1591 * path. Now that we actually do some work, we need to make sure
1594 * Some archs already do call them, luckily irq_enter/exit nest
1597 * Arguably we should visit all archs and update all handlers,
1598 * however a fair share of IPIs are still resched only so this would
1599 * somewhat pessimize the simple resched case.
1602 sched_ttwu_pending();
1605 * Check if someone kicked us for doing the nohz idle load balance.
1607 if (unlikely(got_nohz_idle_kick())) {
1608 this_rq()->idle_balance = 1;
1609 raise_softirq_irqoff(SCHED_SOFTIRQ);
1614 static void ttwu_queue_remote(struct task_struct *p, int cpu)
1616 struct rq *rq = cpu_rq(cpu);
1618 if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) {
1619 if (!set_nr_if_polling(rq->idle))
1620 smp_send_reschedule(cpu);
1622 trace_sched_wake_idle_without_ipi(cpu);
1626 void wake_up_if_idle(int cpu)
1628 struct rq *rq = cpu_rq(cpu);
1629 unsigned long flags;
1633 if (!is_idle_task(rcu_dereference(rq->curr)))
1636 if (set_nr_if_polling(rq->idle)) {
1637 trace_sched_wake_idle_without_ipi(cpu);
1639 raw_spin_lock_irqsave(&rq->lock, flags);
1640 if (is_idle_task(rq->curr))
1641 smp_send_reschedule(cpu);
1642 /* Else cpu is not in idle, do nothing here */
1643 raw_spin_unlock_irqrestore(&rq->lock, flags);
1650 bool cpus_share_cache(int this_cpu, int that_cpu)
1652 return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
1654 #endif /* CONFIG_SMP */
1656 static void ttwu_queue(struct task_struct *p, int cpu)
1658 struct rq *rq = cpu_rq(cpu);
1660 #if defined(CONFIG_SMP)
1661 if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) {
1662 sched_clock_cpu(cpu); /* sync clocks x-cpu */
1663 ttwu_queue_remote(p, cpu);
1668 raw_spin_lock(&rq->lock);
1669 ttwu_do_activate(rq, p, 0);
1670 raw_spin_unlock(&rq->lock);
1674 * try_to_wake_up - wake up a thread
1675 * @p: the thread to be awakened
1676 * @state: the mask of task states that can be woken
1677 * @wake_flags: wake modifier flags (WF_*)
1679 * Put it on the run-queue if it's not already there. The "current"
1680 * thread is always on the run-queue (except when the actual
1681 * re-schedule is in progress), and as such you're allowed to do
1682 * the simpler "current->state = TASK_RUNNING" to mark yourself
1683 * runnable without the overhead of this.
1685 * Return: %true if @p was woken up, %false if it was already running.
1686 * or @state didn't match @p's state.
1689 try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
1691 unsigned long flags;
1692 int cpu, success = 0;
1695 * If we are going to wake up a thread waiting for CONDITION we
1696 * need to ensure that CONDITION=1 done by the caller can not be
1697 * reordered with p->state check below. This pairs with mb() in
1698 * set_current_state() the waiting thread does.
1700 smp_mb__before_spinlock();
1701 raw_spin_lock_irqsave(&p->pi_lock, flags);
1702 if (!(p->state & state))
1705 success = 1; /* we're going to change ->state */
1708 if (p->on_rq && ttwu_remote(p, wake_flags))
1713 * If the owning (remote) cpu is still in the middle of schedule() with
1714 * this task as prev, wait until its done referencing the task.
1719 * Pairs with the smp_wmb() in finish_lock_switch().
1723 p->sched_contributes_to_load = !!task_contributes_to_load(p);
1724 p->state = TASK_WAKING;
1726 if (p->sched_class->task_waking)
1727 p->sched_class->task_waking(p);
1729 cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags);
1730 if (task_cpu(p) != cpu) {
1731 wake_flags |= WF_MIGRATED;
1732 set_task_cpu(p, cpu);
1734 #endif /* CONFIG_SMP */
1738 ttwu_stat(p, cpu, wake_flags);
1740 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1746 * try_to_wake_up_local - try to wake up a local task with rq lock held
1747 * @p: the thread to be awakened
1749 * Put @p on the run-queue if it's not already there. The caller must
1750 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1753 static void try_to_wake_up_local(struct task_struct *p)
1755 struct rq *rq = task_rq(p);
1757 if (WARN_ON_ONCE(rq != this_rq()) ||
1758 WARN_ON_ONCE(p == current))
1761 lockdep_assert_held(&rq->lock);
1763 if (!raw_spin_trylock(&p->pi_lock)) {
1764 raw_spin_unlock(&rq->lock);
1765 raw_spin_lock(&p->pi_lock);
1766 raw_spin_lock(&rq->lock);
1769 if (!(p->state & TASK_NORMAL))
1772 if (!task_on_rq_queued(p))
1773 ttwu_activate(rq, p, ENQUEUE_WAKEUP);
1775 ttwu_do_wakeup(rq, p, 0);
1776 ttwu_stat(p, smp_processor_id(), 0);
1778 raw_spin_unlock(&p->pi_lock);
1782 * wake_up_process - Wake up a specific process
1783 * @p: The process to be woken up.
1785 * Attempt to wake up the nominated process and move it to the set of runnable
1788 * Return: 1 if the process was woken up, 0 if it was already running.
1790 * It may be assumed that this function implies a write memory barrier before
1791 * changing the task state if and only if any tasks are woken up.
1793 int wake_up_process(struct task_struct *p)
1795 WARN_ON(task_is_stopped_or_traced(p));
1796 return try_to_wake_up(p, TASK_NORMAL, 0);
1798 EXPORT_SYMBOL(wake_up_process);
1800 int wake_up_state(struct task_struct *p, unsigned int state)
1802 return try_to_wake_up(p, state, 0);
1806 * This function clears the sched_dl_entity static params.
1808 void __dl_clear_params(struct task_struct *p)
1810 struct sched_dl_entity *dl_se = &p->dl;
1812 dl_se->dl_runtime = 0;
1813 dl_se->dl_deadline = 0;
1814 dl_se->dl_period = 0;
1818 dl_se->dl_throttled = 0;
1820 dl_se->dl_yielded = 0;
1824 * Perform scheduler related setup for a newly forked process p.
1825 * p is forked by current.
1827 * __sched_fork() is basic setup used by init_idle() too:
1829 static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
1834 p->se.exec_start = 0;
1835 p->se.sum_exec_runtime = 0;
1836 p->se.prev_sum_exec_runtime = 0;
1837 p->se.nr_migrations = 0;
1839 INIT_LIST_HEAD(&p->se.group_node);
1841 #ifdef CONFIG_SCHEDSTATS
1842 memset(&p->se.statistics, 0, sizeof(p->se.statistics));
1845 RB_CLEAR_NODE(&p->dl.rb_node);
1846 init_dl_task_timer(&p->dl);
1847 __dl_clear_params(p);
1849 INIT_LIST_HEAD(&p->rt.run_list);
1851 #ifdef CONFIG_PREEMPT_NOTIFIERS
1852 INIT_HLIST_HEAD(&p->preempt_notifiers);
1855 #ifdef CONFIG_NUMA_BALANCING
1856 if (p->mm && atomic_read(&p->mm->mm_users) == 1) {
1857 p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay);
1858 p->mm->numa_scan_seq = 0;
1861 if (clone_flags & CLONE_VM)
1862 p->numa_preferred_nid = current->numa_preferred_nid;
1864 p->numa_preferred_nid = -1;
1866 p->node_stamp = 0ULL;
1867 p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0;
1868 p->numa_scan_period = sysctl_numa_balancing_scan_delay;
1869 p->numa_work.next = &p->numa_work;
1870 p->numa_faults = NULL;
1871 p->last_task_numa_placement = 0;
1872 p->last_sum_exec_runtime = 0;
1874 p->numa_group = NULL;
1875 #endif /* CONFIG_NUMA_BALANCING */
1878 #ifdef CONFIG_NUMA_BALANCING
1879 #ifdef CONFIG_SCHED_DEBUG
1880 void set_numabalancing_state(bool enabled)
1883 sched_feat_set("NUMA");
1885 sched_feat_set("NO_NUMA");
1888 __read_mostly bool numabalancing_enabled;
1890 void set_numabalancing_state(bool enabled)
1892 numabalancing_enabled = enabled;
1894 #endif /* CONFIG_SCHED_DEBUG */
1896 #ifdef CONFIG_PROC_SYSCTL
1897 int sysctl_numa_balancing(struct ctl_table *table, int write,
1898 void __user *buffer, size_t *lenp, loff_t *ppos)
1902 int state = numabalancing_enabled;
1904 if (write && !capable(CAP_SYS_ADMIN))
1909 err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
1913 set_numabalancing_state(state);
1920 * fork()/clone()-time setup:
1922 int sched_fork(unsigned long clone_flags, struct task_struct *p)
1924 unsigned long flags;
1925 int cpu = get_cpu();
1927 __sched_fork(clone_flags, p);
1929 * We mark the process as running here. This guarantees that
1930 * nobody will actually run it, and a signal or other external
1931 * event cannot wake it up and insert it on the runqueue either.
1933 p->state = TASK_RUNNING;
1936 * Make sure we do not leak PI boosting priority to the child.
1938 p->prio = current->normal_prio;
1941 * Revert to default priority/policy on fork if requested.
1943 if (unlikely(p->sched_reset_on_fork)) {
1944 if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
1945 p->policy = SCHED_NORMAL;
1946 p->static_prio = NICE_TO_PRIO(0);
1948 } else if (PRIO_TO_NICE(p->static_prio) < 0)
1949 p->static_prio = NICE_TO_PRIO(0);
1951 p->prio = p->normal_prio = __normal_prio(p);
1955 * We don't need the reset flag anymore after the fork. It has
1956 * fulfilled its duty:
1958 p->sched_reset_on_fork = 0;
1961 if (dl_prio(p->prio)) {
1964 } else if (rt_prio(p->prio)) {
1965 p->sched_class = &rt_sched_class;
1967 p->sched_class = &fair_sched_class;
1970 if (p->sched_class->task_fork)
1971 p->sched_class->task_fork(p);
1974 * The child is not yet in the pid-hash so no cgroup attach races,
1975 * and the cgroup is pinned to this child due to cgroup_fork()
1976 * is ran before sched_fork().
1978 * Silence PROVE_RCU.
1980 raw_spin_lock_irqsave(&p->pi_lock, flags);
1981 set_task_cpu(p, cpu);
1982 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
1984 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1985 if (likely(sched_info_on()))
1986 memset(&p->sched_info, 0, sizeof(p->sched_info));
1988 #if defined(CONFIG_SMP)
1991 init_task_preempt_count(p);
1993 plist_node_init(&p->pushable_tasks, MAX_PRIO);
1994 RB_CLEAR_NODE(&p->pushable_dl_tasks);
2001 unsigned long to_ratio(u64 period, u64 runtime)
2003 if (runtime == RUNTIME_INF)
2007 * Doing this here saves a lot of checks in all
2008 * the calling paths, and returning zero seems
2009 * safe for them anyway.
2014 return div64_u64(runtime << 20, period);
2018 inline struct dl_bw *dl_bw_of(int i)
2020 rcu_lockdep_assert(rcu_read_lock_sched_held(),
2021 "sched RCU must be held");
2022 return &cpu_rq(i)->rd->dl_bw;
2025 static inline int dl_bw_cpus(int i)
2027 struct root_domain *rd = cpu_rq(i)->rd;
2030 rcu_lockdep_assert(rcu_read_lock_sched_held(),
2031 "sched RCU must be held");
2032 for_each_cpu_and(i, rd->span, cpu_active_mask)
2038 inline struct dl_bw *dl_bw_of(int i)
2040 return &cpu_rq(i)->dl.dl_bw;
2043 static inline int dl_bw_cpus(int i)
2050 * We must be sure that accepting a new task (or allowing changing the
2051 * parameters of an existing one) is consistent with the bandwidth
2052 * constraints. If yes, this function also accordingly updates the currently
2053 * allocated bandwidth to reflect the new situation.
2055 * This function is called while holding p's rq->lock.
2057 * XXX we should delay bw change until the task's 0-lag point, see
2060 static int dl_overflow(struct task_struct *p, int policy,
2061 const struct sched_attr *attr)
2064 struct dl_bw *dl_b = dl_bw_of(task_cpu(p));
2065 u64 period = attr->sched_period ?: attr->sched_deadline;
2066 u64 runtime = attr->sched_runtime;
2067 u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0;
2070 if (new_bw == p->dl.dl_bw)
2074 * Either if a task, enters, leave, or stays -deadline but changes
2075 * its parameters, we may need to update accordingly the total
2076 * allocated bandwidth of the container.
2078 raw_spin_lock(&dl_b->lock);
2079 cpus = dl_bw_cpus(task_cpu(p));
2080 if (dl_policy(policy) && !task_has_dl_policy(p) &&
2081 !__dl_overflow(dl_b, cpus, 0, new_bw)) {
2082 __dl_add(dl_b, new_bw);
2084 } else if (dl_policy(policy) && task_has_dl_policy(p) &&
2085 !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) {
2086 __dl_clear(dl_b, p->dl.dl_bw);
2087 __dl_add(dl_b, new_bw);
2089 } else if (!dl_policy(policy) && task_has_dl_policy(p)) {
2090 __dl_clear(dl_b, p->dl.dl_bw);
2093 raw_spin_unlock(&dl_b->lock);
2098 extern void init_dl_bw(struct dl_bw *dl_b);
2101 * wake_up_new_task - wake up a newly created task for the first time.
2103 * This function will do some initial scheduler statistics housekeeping
2104 * that must be done for every newly created context, then puts the task
2105 * on the runqueue and wakes it.
2107 void wake_up_new_task(struct task_struct *p)
2109 unsigned long flags;
2112 raw_spin_lock_irqsave(&p->pi_lock, flags);
2115 * Fork balancing, do it here and not earlier because:
2116 * - cpus_allowed can change in the fork path
2117 * - any previously selected cpu might disappear through hotplug
2119 set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0));
2122 /* Initialize new task's runnable average */
2123 init_task_runnable_average(p);
2124 rq = __task_rq_lock(p);
2125 activate_task(rq, p, 0);
2126 p->on_rq = TASK_ON_RQ_QUEUED;
2127 trace_sched_wakeup_new(p, true);
2128 check_preempt_curr(rq, p, WF_FORK);
2130 if (p->sched_class->task_woken)
2131 p->sched_class->task_woken(rq, p);
2133 task_rq_unlock(rq, p, &flags);
2136 #ifdef CONFIG_PREEMPT_NOTIFIERS
2139 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2140 * @notifier: notifier struct to register
2142 void preempt_notifier_register(struct preempt_notifier *notifier)
2144 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2146 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2149 * preempt_notifier_unregister - no longer interested in preemption notifications
2150 * @notifier: notifier struct to unregister
2152 * This is safe to call from within a preemption notifier.
2154 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2156 hlist_del(¬ifier->link);
2158 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2160 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2162 struct preempt_notifier *notifier;
2164 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
2165 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2169 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2170 struct task_struct *next)
2172 struct preempt_notifier *notifier;
2174 hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
2175 notifier->ops->sched_out(notifier, next);
2178 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2180 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2185 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2186 struct task_struct *next)
2190 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2193 * prepare_task_switch - prepare to switch tasks
2194 * @rq: the runqueue preparing to switch
2195 * @prev: the current task that is being switched out
2196 * @next: the task we are going to switch to.
2198 * This is called with the rq lock held and interrupts off. It must
2199 * be paired with a subsequent finish_task_switch after the context
2202 * prepare_task_switch sets up locking and calls architecture specific
2206 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2207 struct task_struct *next)
2209 trace_sched_switch(prev, next);
2210 sched_info_switch(rq, prev, next);
2211 perf_event_task_sched_out(prev, next);
2212 fire_sched_out_preempt_notifiers(prev, next);
2213 prepare_lock_switch(rq, next);
2214 prepare_arch_switch(next);
2218 * finish_task_switch - clean up after a task-switch
2219 * @prev: the thread we just switched away from.
2221 * finish_task_switch must be called after the context switch, paired
2222 * with a prepare_task_switch call before the context switch.
2223 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2224 * and do any other architecture-specific cleanup actions.
2226 * Note that we may have delayed dropping an mm in context_switch(). If
2227 * so, we finish that here outside of the runqueue lock. (Doing it
2228 * with the lock held can cause deadlocks; see schedule() for
2231 * The context switch have flipped the stack from under us and restored the
2232 * local variables which were saved when this task called schedule() in the
2233 * past. prev == current is still correct but we need to recalculate this_rq
2234 * because prev may have moved to another CPU.
2236 static struct rq *finish_task_switch(struct task_struct *prev)
2237 __releases(rq->lock)
2239 struct rq *rq = this_rq();
2240 struct mm_struct *mm = rq->prev_mm;
2246 * A task struct has one reference for the use as "current".
2247 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2248 * schedule one last time. The schedule call will never return, and
2249 * the scheduled task must drop that reference.
2250 * The test for TASK_DEAD must occur while the runqueue locks are
2251 * still held, otherwise prev could be scheduled on another cpu, die
2252 * there before we look at prev->state, and then the reference would
2254 * Manfred Spraul <manfred@colorfullife.com>
2256 prev_state = prev->state;
2257 vtime_task_switch(prev);
2258 finish_arch_switch(prev);
2259 perf_event_task_sched_in(prev, current);
2260 finish_lock_switch(rq, prev);
2261 finish_arch_post_lock_switch();
2263 fire_sched_in_preempt_notifiers(current);
2266 if (unlikely(prev_state == TASK_DEAD)) {
2267 if (prev->sched_class->task_dead)
2268 prev->sched_class->task_dead(prev);
2271 * Remove function-return probe instances associated with this
2272 * task and put them back on the free list.
2274 kprobe_flush_task(prev);
2275 put_task_struct(prev);
2278 tick_nohz_task_switch(current);
2284 /* rq->lock is NOT held, but preemption is disabled */
2285 static inline void post_schedule(struct rq *rq)
2287 if (rq->post_schedule) {
2288 unsigned long flags;
2290 raw_spin_lock_irqsave(&rq->lock, flags);
2291 if (rq->curr->sched_class->post_schedule)
2292 rq->curr->sched_class->post_schedule(rq);
2293 raw_spin_unlock_irqrestore(&rq->lock, flags);
2295 rq->post_schedule = 0;
2301 static inline void post_schedule(struct rq *rq)
2308 * schedule_tail - first thing a freshly forked thread must call.
2309 * @prev: the thread we just switched away from.
2311 asmlinkage __visible void schedule_tail(struct task_struct *prev)
2312 __releases(rq->lock)
2316 /* finish_task_switch() drops rq->lock and enables preemtion */
2318 rq = finish_task_switch(prev);
2322 if (current->set_child_tid)
2323 put_user(task_pid_vnr(current), current->set_child_tid);
2327 * context_switch - switch to the new MM and the new thread's register state.
2329 static inline struct rq *
2330 context_switch(struct rq *rq, struct task_struct *prev,
2331 struct task_struct *next)
2333 struct mm_struct *mm, *oldmm;
2335 prepare_task_switch(rq, prev, next);
2338 oldmm = prev->active_mm;
2340 * For paravirt, this is coupled with an exit in switch_to to
2341 * combine the page table reload and the switch backend into
2344 arch_start_context_switch(prev);
2347 next->active_mm = oldmm;
2348 atomic_inc(&oldmm->mm_count);
2349 enter_lazy_tlb(oldmm, next);
2351 switch_mm(oldmm, mm, next);
2354 prev->active_mm = NULL;
2355 rq->prev_mm = oldmm;
2358 * Since the runqueue lock will be released by the next
2359 * task (which is an invalid locking op but in the case
2360 * of the scheduler it's an obvious special-case), so we
2361 * do an early lockdep release here:
2363 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2365 context_tracking_task_switch(prev, next);
2366 /* Here we just switch the register state and the stack. */
2367 switch_to(prev, next, prev);
2370 return finish_task_switch(prev);
2374 * nr_running and nr_context_switches:
2376 * externally visible scheduler statistics: current number of runnable
2377 * threads, total number of context switches performed since bootup.
2379 unsigned long nr_running(void)
2381 unsigned long i, sum = 0;
2383 for_each_online_cpu(i)
2384 sum += cpu_rq(i)->nr_running;
2390 * Check if only the current task is running on the cpu.
2392 bool single_task_running(void)
2394 if (cpu_rq(smp_processor_id())->nr_running == 1)
2399 EXPORT_SYMBOL(single_task_running);
2401 unsigned long long nr_context_switches(void)
2404 unsigned long long sum = 0;
2406 for_each_possible_cpu(i)
2407 sum += cpu_rq(i)->nr_switches;
2412 unsigned long nr_iowait(void)
2414 unsigned long i, sum = 0;
2416 for_each_possible_cpu(i)
2417 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2422 unsigned long nr_iowait_cpu(int cpu)
2424 struct rq *this = cpu_rq(cpu);
2425 return atomic_read(&this->nr_iowait);
2428 void get_iowait_load(unsigned long *nr_waiters, unsigned long *load)
2430 struct rq *this = this_rq();
2431 *nr_waiters = atomic_read(&this->nr_iowait);
2432 *load = this->cpu_load[0];
2438 * sched_exec - execve() is a valuable balancing opportunity, because at
2439 * this point the task has the smallest effective memory and cache footprint.
2441 void sched_exec(void)
2443 struct task_struct *p = current;
2444 unsigned long flags;
2447 raw_spin_lock_irqsave(&p->pi_lock, flags);
2448 dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0);
2449 if (dest_cpu == smp_processor_id())
2452 if (likely(cpu_active(dest_cpu))) {
2453 struct migration_arg arg = { p, dest_cpu };
2455 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2456 stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
2460 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
2465 DEFINE_PER_CPU(struct kernel_stat, kstat);
2466 DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
2468 EXPORT_PER_CPU_SYMBOL(kstat);
2469 EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
2472 * Return accounted runtime for the task.
2473 * In case the task is currently running, return the runtime plus current's
2474 * pending runtime that have not been accounted yet.
2476 unsigned long long task_sched_runtime(struct task_struct *p)
2478 unsigned long flags;
2482 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2484 * 64-bit doesn't need locks to atomically read a 64bit value.
2485 * So we have a optimization chance when the task's delta_exec is 0.
2486 * Reading ->on_cpu is racy, but this is ok.
2488 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2489 * If we race with it entering cpu, unaccounted time is 0. This is
2490 * indistinguishable from the read occurring a few cycles earlier.
2491 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
2492 * been accounted, so we're correct here as well.
2494 if (!p->on_cpu || !task_on_rq_queued(p))
2495 return p->se.sum_exec_runtime;
2498 rq = task_rq_lock(p, &flags);
2500 * Must be ->curr _and_ ->on_rq. If dequeued, we would
2501 * project cycles that may never be accounted to this
2502 * thread, breaking clock_gettime().
2504 if (task_current(rq, p) && task_on_rq_queued(p)) {
2505 update_rq_clock(rq);
2506 p->sched_class->update_curr(rq);
2508 ns = p->se.sum_exec_runtime;
2509 task_rq_unlock(rq, p, &flags);
2515 * This function gets called by the timer code, with HZ frequency.
2516 * We call it with interrupts disabled.
2518 void scheduler_tick(void)
2520 int cpu = smp_processor_id();
2521 struct rq *rq = cpu_rq(cpu);
2522 struct task_struct *curr = rq->curr;
2526 raw_spin_lock(&rq->lock);
2527 update_rq_clock(rq);
2528 curr->sched_class->task_tick(rq, curr, 0);
2529 update_cpu_load_active(rq);
2530 raw_spin_unlock(&rq->lock);
2532 perf_event_task_tick();
2535 rq->idle_balance = idle_cpu(cpu);
2536 trigger_load_balance(rq);
2538 rq_last_tick_reset(rq);
2541 #ifdef CONFIG_NO_HZ_FULL
2543 * scheduler_tick_max_deferment
2545 * Keep at least one tick per second when a single
2546 * active task is running because the scheduler doesn't
2547 * yet completely support full dynticks environment.
2549 * This makes sure that uptime, CFS vruntime, load
2550 * balancing, etc... continue to move forward, even
2551 * with a very low granularity.
2553 * Return: Maximum deferment in nanoseconds.
2555 u64 scheduler_tick_max_deferment(void)
2557 struct rq *rq = this_rq();
2558 unsigned long next, now = ACCESS_ONCE(jiffies);
2560 next = rq->last_sched_tick + HZ;
2562 if (time_before_eq(next, now))
2565 return jiffies_to_nsecs(next - now);
2569 notrace unsigned long get_parent_ip(unsigned long addr)
2571 if (in_lock_functions(addr)) {
2572 addr = CALLER_ADDR2;
2573 if (in_lock_functions(addr))
2574 addr = CALLER_ADDR3;
2579 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2580 defined(CONFIG_PREEMPT_TRACER))
2582 void preempt_count_add(int val)
2584 #ifdef CONFIG_DEBUG_PREEMPT
2588 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2591 __preempt_count_add(val);
2592 #ifdef CONFIG_DEBUG_PREEMPT
2594 * Spinlock count overflowing soon?
2596 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
2599 if (preempt_count() == val) {
2600 unsigned long ip = get_parent_ip(CALLER_ADDR1);
2601 #ifdef CONFIG_DEBUG_PREEMPT
2602 current->preempt_disable_ip = ip;
2604 trace_preempt_off(CALLER_ADDR0, ip);
2607 EXPORT_SYMBOL(preempt_count_add);
2608 NOKPROBE_SYMBOL(preempt_count_add);
2610 void preempt_count_sub(int val)
2612 #ifdef CONFIG_DEBUG_PREEMPT
2616 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
2619 * Is the spinlock portion underflowing?
2621 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
2622 !(preempt_count() & PREEMPT_MASK)))
2626 if (preempt_count() == val)
2627 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
2628 __preempt_count_sub(val);
2630 EXPORT_SYMBOL(preempt_count_sub);
2631 NOKPROBE_SYMBOL(preempt_count_sub);
2636 * Print scheduling while atomic bug:
2638 static noinline void __schedule_bug(struct task_struct *prev)
2640 if (oops_in_progress)
2643 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
2644 prev->comm, prev->pid, preempt_count());
2646 debug_show_held_locks(prev);
2648 if (irqs_disabled())
2649 print_irqtrace_events(prev);
2650 #ifdef CONFIG_DEBUG_PREEMPT
2651 if (in_atomic_preempt_off()) {
2652 pr_err("Preemption disabled at:");
2653 print_ip_sym(current->preempt_disable_ip);
2658 add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
2662 * Various schedule()-time debugging checks and statistics:
2664 static inline void schedule_debug(struct task_struct *prev)
2666 #ifdef CONFIG_SCHED_STACK_END_CHECK
2667 BUG_ON(unlikely(task_stack_end_corrupted(prev)));
2670 * Test if we are atomic. Since do_exit() needs to call into
2671 * schedule() atomically, we ignore that path. Otherwise whine
2672 * if we are scheduling when we should not.
2674 if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD))
2675 __schedule_bug(prev);
2678 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
2680 schedstat_inc(this_rq(), sched_count);
2684 * Pick up the highest-prio task:
2686 static inline struct task_struct *
2687 pick_next_task(struct rq *rq, struct task_struct *prev)
2689 const struct sched_class *class = &fair_sched_class;
2690 struct task_struct *p;
2693 * Optimization: we know that if all tasks are in
2694 * the fair class we can call that function directly:
2696 if (likely(prev->sched_class == class &&
2697 rq->nr_running == rq->cfs.h_nr_running)) {
2698 p = fair_sched_class.pick_next_task(rq, prev);
2699 if (unlikely(p == RETRY_TASK))
2702 /* assumes fair_sched_class->next == idle_sched_class */
2704 p = idle_sched_class.pick_next_task(rq, prev);
2710 for_each_class(class) {
2711 p = class->pick_next_task(rq, prev);
2713 if (unlikely(p == RETRY_TASK))
2719 BUG(); /* the idle class will always have a runnable task */
2723 * __schedule() is the main scheduler function.
2725 * The main means of driving the scheduler and thus entering this function are:
2727 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2729 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2730 * paths. For example, see arch/x86/entry_64.S.
2732 * To drive preemption between tasks, the scheduler sets the flag in timer
2733 * interrupt handler scheduler_tick().
2735 * 3. Wakeups don't really cause entry into schedule(). They add a
2736 * task to the run-queue and that's it.
2738 * Now, if the new task added to the run-queue preempts the current
2739 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2740 * called on the nearest possible occasion:
2742 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2744 * - in syscall or exception context, at the next outmost
2745 * preempt_enable(). (this might be as soon as the wake_up()'s
2748 * - in IRQ context, return from interrupt-handler to
2749 * preemptible context
2751 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2754 * - cond_resched() call
2755 * - explicit schedule() call
2756 * - return from syscall or exception to user-space
2757 * - return from interrupt-handler to user-space
2759 static void __sched __schedule(void)
2761 struct task_struct *prev, *next;
2762 unsigned long *switch_count;
2768 cpu = smp_processor_id();
2770 rcu_note_context_switch();
2773 schedule_debug(prev);
2775 if (sched_feat(HRTICK))
2779 * Make sure that signal_pending_state()->signal_pending() below
2780 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2781 * done by the caller to avoid the race with signal_wake_up().
2783 smp_mb__before_spinlock();
2784 raw_spin_lock_irq(&rq->lock);
2786 switch_count = &prev->nivcsw;
2787 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
2788 if (unlikely(signal_pending_state(prev->state, prev))) {
2789 prev->state = TASK_RUNNING;
2791 deactivate_task(rq, prev, DEQUEUE_SLEEP);
2795 * If a worker went to sleep, notify and ask workqueue
2796 * whether it wants to wake up a task to maintain
2799 if (prev->flags & PF_WQ_WORKER) {
2800 struct task_struct *to_wakeup;
2802 to_wakeup = wq_worker_sleeping(prev, cpu);
2804 try_to_wake_up_local(to_wakeup);
2807 switch_count = &prev->nvcsw;
2810 if (task_on_rq_queued(prev) || rq->skip_clock_update < 0)
2811 update_rq_clock(rq);
2813 next = pick_next_task(rq, prev);
2814 clear_tsk_need_resched(prev);
2815 clear_preempt_need_resched();
2816 rq->skip_clock_update = 0;
2818 if (likely(prev != next)) {
2823 rq = context_switch(rq, prev, next); /* unlocks the rq */
2826 raw_spin_unlock_irq(&rq->lock);
2830 sched_preempt_enable_no_resched();
2835 static inline void sched_submit_work(struct task_struct *tsk)
2837 if (!tsk->state || tsk_is_pi_blocked(tsk))
2840 * If we are going to sleep and we have plugged IO queued,
2841 * make sure to submit it to avoid deadlocks.
2843 if (blk_needs_flush_plug(tsk))
2844 blk_schedule_flush_plug(tsk);
2847 asmlinkage __visible void __sched schedule(void)
2849 struct task_struct *tsk = current;
2851 sched_submit_work(tsk);
2854 EXPORT_SYMBOL(schedule);
2856 #ifdef CONFIG_CONTEXT_TRACKING
2857 asmlinkage __visible void __sched schedule_user(void)
2860 * If we come here after a random call to set_need_resched(),
2861 * or we have been woken up remotely but the IPI has not yet arrived,
2862 * we haven't yet exited the RCU idle mode. Do it here manually until
2863 * we find a better solution.
2865 * NB: There are buggy callers of this function. Ideally we
2866 * should warn if prev_state != IN_USER, but that will trigger
2867 * too frequently to make sense yet.
2869 enum ctx_state prev_state = exception_enter();
2871 exception_exit(prev_state);
2876 * schedule_preempt_disabled - called with preemption disabled
2878 * Returns with preemption disabled. Note: preempt_count must be 1
2880 void __sched schedule_preempt_disabled(void)
2882 sched_preempt_enable_no_resched();
2887 #ifdef CONFIG_PREEMPT
2889 * this is the entry point to schedule() from in-kernel preemption
2890 * off of preempt_enable. Kernel preemptions off return from interrupt
2891 * occur there and call schedule directly.
2893 asmlinkage __visible void __sched notrace preempt_schedule(void)
2896 * If there is a non-zero preempt_count or interrupts are disabled,
2897 * we do not want to preempt the current task. Just return..
2899 if (likely(!preemptible()))
2903 __preempt_count_add(PREEMPT_ACTIVE);
2905 __preempt_count_sub(PREEMPT_ACTIVE);
2908 * Check again in case we missed a preemption opportunity
2909 * between schedule and now.
2912 } while (need_resched());
2914 NOKPROBE_SYMBOL(preempt_schedule);
2915 EXPORT_SYMBOL(preempt_schedule);
2917 #ifdef CONFIG_CONTEXT_TRACKING
2919 * preempt_schedule_context - preempt_schedule called by tracing
2921 * The tracing infrastructure uses preempt_enable_notrace to prevent
2922 * recursion and tracing preempt enabling caused by the tracing
2923 * infrastructure itself. But as tracing can happen in areas coming
2924 * from userspace or just about to enter userspace, a preempt enable
2925 * can occur before user_exit() is called. This will cause the scheduler
2926 * to be called when the system is still in usermode.
2928 * To prevent this, the preempt_enable_notrace will use this function
2929 * instead of preempt_schedule() to exit user context if needed before
2930 * calling the scheduler.
2932 asmlinkage __visible void __sched notrace preempt_schedule_context(void)
2934 enum ctx_state prev_ctx;
2936 if (likely(!preemptible()))
2940 __preempt_count_add(PREEMPT_ACTIVE);
2942 * Needs preempt disabled in case user_exit() is traced
2943 * and the tracer calls preempt_enable_notrace() causing
2944 * an infinite recursion.
2946 prev_ctx = exception_enter();
2948 exception_exit(prev_ctx);
2950 __preempt_count_sub(PREEMPT_ACTIVE);
2952 } while (need_resched());
2954 EXPORT_SYMBOL_GPL(preempt_schedule_context);
2955 #endif /* CONFIG_CONTEXT_TRACKING */
2957 #endif /* CONFIG_PREEMPT */
2960 * this is the entry point to schedule() from kernel preemption
2961 * off of irq context.
2962 * Note, that this is called and return with irqs disabled. This will
2963 * protect us against recursive calling from irq.
2965 asmlinkage __visible void __sched preempt_schedule_irq(void)
2967 enum ctx_state prev_state;
2969 /* Catch callers which need to be fixed */
2970 BUG_ON(preempt_count() || !irqs_disabled());
2972 prev_state = exception_enter();
2975 __preempt_count_add(PREEMPT_ACTIVE);
2978 local_irq_disable();
2979 __preempt_count_sub(PREEMPT_ACTIVE);
2982 * Check again in case we missed a preemption opportunity
2983 * between schedule and now.
2986 } while (need_resched());
2988 exception_exit(prev_state);
2991 int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
2994 return try_to_wake_up(curr->private, mode, wake_flags);
2996 EXPORT_SYMBOL(default_wake_function);
2998 #ifdef CONFIG_RT_MUTEXES
3001 * rt_mutex_setprio - set the current priority of a task
3003 * @prio: prio value (kernel-internal form)
3005 * This function changes the 'effective' priority of a task. It does
3006 * not touch ->normal_prio like __setscheduler().
3008 * Used by the rt_mutex code to implement priority inheritance
3009 * logic. Call site only calls if the priority of the task changed.
3011 void rt_mutex_setprio(struct task_struct *p, int prio)
3013 int oldprio, queued, running, enqueue_flag = 0;
3015 const struct sched_class *prev_class;
3017 BUG_ON(prio > MAX_PRIO);
3019 rq = __task_rq_lock(p);
3022 * Idle task boosting is a nono in general. There is one
3023 * exception, when PREEMPT_RT and NOHZ is active:
3025 * The idle task calls get_next_timer_interrupt() and holds
3026 * the timer wheel base->lock on the CPU and another CPU wants
3027 * to access the timer (probably to cancel it). We can safely
3028 * ignore the boosting request, as the idle CPU runs this code
3029 * with interrupts disabled and will complete the lock
3030 * protected section without being interrupted. So there is no
3031 * real need to boost.
3033 if (unlikely(p == rq->idle)) {
3034 WARN_ON(p != rq->curr);
3035 WARN_ON(p->pi_blocked_on);
3039 trace_sched_pi_setprio(p, prio);
3041 prev_class = p->sched_class;
3042 queued = task_on_rq_queued(p);
3043 running = task_current(rq, p);
3045 dequeue_task(rq, p, 0);
3047 put_prev_task(rq, p);
3050 * Boosting condition are:
3051 * 1. -rt task is running and holds mutex A
3052 * --> -dl task blocks on mutex A
3054 * 2. -dl task is running and holds mutex A
3055 * --> -dl task blocks on mutex A and could preempt the
3058 if (dl_prio(prio)) {
3059 struct task_struct *pi_task = rt_mutex_get_top_task(p);
3060 if (!dl_prio(p->normal_prio) ||
3061 (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) {
3062 p->dl.dl_boosted = 1;
3063 p->dl.dl_throttled = 0;
3064 enqueue_flag = ENQUEUE_REPLENISH;
3066 p->dl.dl_boosted = 0;
3067 p->sched_class = &dl_sched_class;
3068 } else if (rt_prio(prio)) {
3069 if (dl_prio(oldprio))
3070 p->dl.dl_boosted = 0;
3072 enqueue_flag = ENQUEUE_HEAD;
3073 p->sched_class = &rt_sched_class;
3075 if (dl_prio(oldprio))
3076 p->dl.dl_boosted = 0;
3077 p->sched_class = &fair_sched_class;
3083 p->sched_class->set_curr_task(rq);
3085 enqueue_task(rq, p, enqueue_flag);
3087 check_class_changed(rq, p, prev_class, oldprio);
3089 __task_rq_unlock(rq);
3093 void set_user_nice(struct task_struct *p, long nice)
3095 int old_prio, delta, queued;
3096 unsigned long flags;
3099 if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
3102 * We have to be careful, if called from sys_setpriority(),
3103 * the task might be in the middle of scheduling on another CPU.
3105 rq = task_rq_lock(p, &flags);
3107 * The RT priorities are set via sched_setscheduler(), but we still
3108 * allow the 'normal' nice value to be set - but as expected
3109 * it wont have any effect on scheduling until the task is
3110 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3112 if (task_has_dl_policy(p) || task_has_rt_policy(p)) {
3113 p->static_prio = NICE_TO_PRIO(nice);
3116 queued = task_on_rq_queued(p);
3118 dequeue_task(rq, p, 0);
3120 p->static_prio = NICE_TO_PRIO(nice);
3123 p->prio = effective_prio(p);
3124 delta = p->prio - old_prio;
3127 enqueue_task(rq, p, 0);
3129 * If the task increased its priority or is running and
3130 * lowered its priority, then reschedule its CPU:
3132 if (delta < 0 || (delta > 0 && task_running(rq, p)))
3136 task_rq_unlock(rq, p, &flags);
3138 EXPORT_SYMBOL(set_user_nice);
3141 * can_nice - check if a task can reduce its nice value
3145 int can_nice(const struct task_struct *p, const int nice)
3147 /* convert nice value [19,-20] to rlimit style value [1,40] */
3148 int nice_rlim = nice_to_rlimit(nice);
3150 return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
3151 capable(CAP_SYS_NICE));
3154 #ifdef __ARCH_WANT_SYS_NICE
3157 * sys_nice - change the priority of the current process.
3158 * @increment: priority increment
3160 * sys_setpriority is a more generic, but much slower function that
3161 * does similar things.
3163 SYSCALL_DEFINE1(nice, int, increment)
3168 * Setpriority might change our priority at the same moment.
3169 * We don't have to worry. Conceptually one call occurs first
3170 * and we have a single winner.
3172 increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
3173 nice = task_nice(current) + increment;
3175 nice = clamp_val(nice, MIN_NICE, MAX_NICE);
3176 if (increment < 0 && !can_nice(current, nice))
3179 retval = security_task_setnice(current, nice);
3183 set_user_nice(current, nice);
3190 * task_prio - return the priority value of a given task.
3191 * @p: the task in question.
3193 * Return: The priority value as seen by users in /proc.
3194 * RT tasks are offset by -200. Normal tasks are centered
3195 * around 0, value goes from -16 to +15.
3197 int task_prio(const struct task_struct *p)
3199 return p->prio - MAX_RT_PRIO;
3203 * idle_cpu - is a given cpu idle currently?
3204 * @cpu: the processor in question.
3206 * Return: 1 if the CPU is currently idle. 0 otherwise.
3208 int idle_cpu(int cpu)
3210 struct rq *rq = cpu_rq(cpu);
3212 if (rq->curr != rq->idle)
3219 if (!llist_empty(&rq->wake_list))
3227 * idle_task - return the idle task for a given cpu.
3228 * @cpu: the processor in question.
3230 * Return: The idle task for the cpu @cpu.
3232 struct task_struct *idle_task(int cpu)
3234 return cpu_rq(cpu)->idle;
3238 * find_process_by_pid - find a process with a matching PID value.
3239 * @pid: the pid in question.
3241 * The task of @pid, if found. %NULL otherwise.
3243 static struct task_struct *find_process_by_pid(pid_t pid)
3245 return pid ? find_task_by_vpid(pid) : current;
3249 * This function initializes the sched_dl_entity of a newly becoming
3250 * SCHED_DEADLINE task.
3252 * Only the static values are considered here, the actual runtime and the
3253 * absolute deadline will be properly calculated when the task is enqueued
3254 * for the first time with its new policy.
3257 __setparam_dl(struct task_struct *p, const struct sched_attr *attr)
3259 struct sched_dl_entity *dl_se = &p->dl;
3261 dl_se->dl_runtime = attr->sched_runtime;
3262 dl_se->dl_deadline = attr->sched_deadline;
3263 dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline;
3264 dl_se->flags = attr->sched_flags;
3265 dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime);
3268 * Changing the parameters of a task is 'tricky' and we're not doing
3269 * the correct thing -- also see task_dead_dl() and switched_from_dl().
3271 * What we SHOULD do is delay the bandwidth release until the 0-lag
3272 * point. This would include retaining the task_struct until that time
3273 * and change dl_overflow() to not immediately decrement the current
3276 * Instead we retain the current runtime/deadline and let the new
3277 * parameters take effect after the current reservation period lapses.
3278 * This is safe (albeit pessimistic) because the 0-lag point is always
3279 * before the current scheduling deadline.
3281 * We can still have temporary overloads because we do not delay the
3282 * change in bandwidth until that time; so admission control is
3283 * not on the safe side. It does however guarantee tasks will never
3284 * consume more than promised.
3289 * sched_setparam() passes in -1 for its policy, to let the functions
3290 * it calls know not to change it.
3292 #define SETPARAM_POLICY -1
3294 static void __setscheduler_params(struct task_struct *p,
3295 const struct sched_attr *attr)
3297 int policy = attr->sched_policy;
3299 if (policy == SETPARAM_POLICY)
3304 if (dl_policy(policy))
3305 __setparam_dl(p, attr);
3306 else if (fair_policy(policy))
3307 p->static_prio = NICE_TO_PRIO(attr->sched_nice);
3310 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3311 * !rt_policy. Always setting this ensures that things like
3312 * getparam()/getattr() don't report silly values for !rt tasks.
3314 p->rt_priority = attr->sched_priority;
3315 p->normal_prio = normal_prio(p);
3319 /* Actually do priority change: must hold pi & rq lock. */
3320 static void __setscheduler(struct rq *rq, struct task_struct *p,
3321 const struct sched_attr *attr)
3323 __setscheduler_params(p, attr);
3326 * If we get here, there was no pi waiters boosting the
3327 * task. It is safe to use the normal prio.
3329 p->prio = normal_prio(p);
3331 if (dl_prio(p->prio))
3332 p->sched_class = &dl_sched_class;
3333 else if (rt_prio(p->prio))
3334 p->sched_class = &rt_sched_class;
3336 p->sched_class = &fair_sched_class;
3340 __getparam_dl(struct task_struct *p, struct sched_attr *attr)
3342 struct sched_dl_entity *dl_se = &p->dl;
3344 attr->sched_priority = p->rt_priority;
3345 attr->sched_runtime = dl_se->dl_runtime;
3346 attr->sched_deadline = dl_se->dl_deadline;
3347 attr->sched_period = dl_se->dl_period;
3348 attr->sched_flags = dl_se->flags;
3352 * This function validates the new parameters of a -deadline task.
3353 * We ask for the deadline not being zero, and greater or equal
3354 * than the runtime, as well as the period of being zero or
3355 * greater than deadline. Furthermore, we have to be sure that
3356 * user parameters are above the internal resolution of 1us (we
3357 * check sched_runtime only since it is always the smaller one) and
3358 * below 2^63 ns (we have to check both sched_deadline and
3359 * sched_period, as the latter can be zero).
3362 __checkparam_dl(const struct sched_attr *attr)
3365 if (attr->sched_deadline == 0)
3369 * Since we truncate DL_SCALE bits, make sure we're at least
3372 if (attr->sched_runtime < (1ULL << DL_SCALE))
3376 * Since we use the MSB for wrap-around and sign issues, make
3377 * sure it's not set (mind that period can be equal to zero).
3379 if (attr->sched_deadline & (1ULL << 63) ||
3380 attr->sched_period & (1ULL << 63))
3383 /* runtime <= deadline <= period (if period != 0) */
3384 if ((attr->sched_period != 0 &&
3385 attr->sched_period < attr->sched_deadline) ||
3386 attr->sched_deadline < attr->sched_runtime)
3393 * check the target process has a UID that matches the current process's
3395 static bool check_same_owner(struct task_struct *p)
3397 const struct cred *cred = current_cred(), *pcred;
3401 pcred = __task_cred(p);
3402 match = (uid_eq(cred->euid, pcred->euid) ||
3403 uid_eq(cred->euid, pcred->uid));
3408 static int __sched_setscheduler(struct task_struct *p,
3409 const struct sched_attr *attr,
3412 int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 :
3413 MAX_RT_PRIO - 1 - attr->sched_priority;
3414 int retval, oldprio, oldpolicy = -1, queued, running;
3415 int policy = attr->sched_policy;
3416 unsigned long flags;
3417 const struct sched_class *prev_class;
3421 /* may grab non-irq protected spin_locks */
3422 BUG_ON(in_interrupt());
3424 /* double check policy once rq lock held */
3426 reset_on_fork = p->sched_reset_on_fork;
3427 policy = oldpolicy = p->policy;
3429 reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);
3431 if (policy != SCHED_DEADLINE &&
3432 policy != SCHED_FIFO && policy != SCHED_RR &&
3433 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
3434 policy != SCHED_IDLE)
3438 if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK))
3442 * Valid priorities for SCHED_FIFO and SCHED_RR are
3443 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3444 * SCHED_BATCH and SCHED_IDLE is 0.
3446 if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) ||
3447 (!p->mm && attr->sched_priority > MAX_RT_PRIO-1))
3449 if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
3450 (rt_policy(policy) != (attr->sched_priority != 0)))
3454 * Allow unprivileged RT tasks to decrease priority:
3456 if (user && !capable(CAP_SYS_NICE)) {
3457 if (fair_policy(policy)) {
3458 if (attr->sched_nice < task_nice(p) &&
3459 !can_nice(p, attr->sched_nice))
3463 if (rt_policy(policy)) {
3464 unsigned long rlim_rtprio =
3465 task_rlimit(p, RLIMIT_RTPRIO);
3467 /* can't set/change the rt policy */
3468 if (policy != p->policy && !rlim_rtprio)
3471 /* can't increase priority */
3472 if (attr->sched_priority > p->rt_priority &&
3473 attr->sched_priority > rlim_rtprio)
3478 * Can't set/change SCHED_DEADLINE policy at all for now
3479 * (safest behavior); in the future we would like to allow
3480 * unprivileged DL tasks to increase their relative deadline
3481 * or reduce their runtime (both ways reducing utilization)
3483 if (dl_policy(policy))
3487 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3488 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3490 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
3491 if (!can_nice(p, task_nice(p)))
3495 /* can't change other user's priorities */
3496 if (!check_same_owner(p))
3499 /* Normal users shall not reset the sched_reset_on_fork flag */
3500 if (p->sched_reset_on_fork && !reset_on_fork)
3505 retval = security_task_setscheduler(p);
3511 * make sure no PI-waiters arrive (or leave) while we are
3512 * changing the priority of the task:
3514 * To be able to change p->policy safely, the appropriate
3515 * runqueue lock must be held.
3517 rq = task_rq_lock(p, &flags);
3520 * Changing the policy of the stop threads its a very bad idea
3522 if (p == rq->stop) {
3523 task_rq_unlock(rq, p, &flags);
3528 * If not changing anything there's no need to proceed further,
3529 * but store a possible modification of reset_on_fork.
3531 if (unlikely(policy == p->policy)) {
3532 if (fair_policy(policy) && attr->sched_nice != task_nice(p))
3534 if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
3536 if (dl_policy(policy))
3539 p->sched_reset_on_fork = reset_on_fork;
3540 task_rq_unlock(rq, p, &flags);
3546 #ifdef CONFIG_RT_GROUP_SCHED
3548 * Do not allow realtime tasks into groups that have no runtime
3551 if (rt_bandwidth_enabled() && rt_policy(policy) &&
3552 task_group(p)->rt_bandwidth.rt_runtime == 0 &&
3553 !task_group_is_autogroup(task_group(p))) {
3554 task_rq_unlock(rq, p, &flags);
3559 if (dl_bandwidth_enabled() && dl_policy(policy)) {
3560 cpumask_t *span = rq->rd->span;
3563 * Don't allow tasks with an affinity mask smaller than
3564 * the entire root_domain to become SCHED_DEADLINE. We
3565 * will also fail if there's no bandwidth available.
3567 if (!cpumask_subset(span, &p->cpus_allowed) ||
3568 rq->rd->dl_bw.bw == 0) {
3569 task_rq_unlock(rq, p, &flags);
3576 /* recheck policy now with rq lock held */
3577 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
3578 policy = oldpolicy = -1;
3579 task_rq_unlock(rq, p, &flags);
3584 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3585 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3588 if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) {
3589 task_rq_unlock(rq, p, &flags);
3593 p->sched_reset_on_fork = reset_on_fork;
3597 * Special case for priority boosted tasks.
3599 * If the new priority is lower or equal (user space view)
3600 * than the current (boosted) priority, we just store the new
3601 * normal parameters and do not touch the scheduler class and
3602 * the runqueue. This will be done when the task deboost
3605 if (rt_mutex_check_prio(p, newprio)) {
3606 __setscheduler_params(p, attr);
3607 task_rq_unlock(rq, p, &flags);
3611 queued = task_on_rq_queued(p);
3612 running = task_current(rq, p);
3614 dequeue_task(rq, p, 0);
3616 put_prev_task(rq, p);
3618 prev_class = p->sched_class;
3619 __setscheduler(rq, p, attr);
3622 p->sched_class->set_curr_task(rq);
3625 * We enqueue to tail when the priority of a task is
3626 * increased (user space view).
3628 enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0);
3631 check_class_changed(rq, p, prev_class, oldprio);
3632 task_rq_unlock(rq, p, &flags);
3634 rt_mutex_adjust_pi(p);
3639 static int _sched_setscheduler(struct task_struct *p, int policy,
3640 const struct sched_param *param, bool check)
3642 struct sched_attr attr = {
3643 .sched_policy = policy,
3644 .sched_priority = param->sched_priority,
3645 .sched_nice = PRIO_TO_NICE(p->static_prio),
3648 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
3649 if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
3650 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
3651 policy &= ~SCHED_RESET_ON_FORK;
3652 attr.sched_policy = policy;
3655 return __sched_setscheduler(p, &attr, check);
3658 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3659 * @p: the task in question.
3660 * @policy: new policy.
3661 * @param: structure containing the new RT priority.
3663 * Return: 0 on success. An error code otherwise.
3665 * NOTE that the task may be already dead.
3667 int sched_setscheduler(struct task_struct *p, int policy,
3668 const struct sched_param *param)
3670 return _sched_setscheduler(p, policy, param, true);
3672 EXPORT_SYMBOL_GPL(sched_setscheduler);
3674 int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
3676 return __sched_setscheduler(p, attr, true);
3678 EXPORT_SYMBOL_GPL(sched_setattr);
3681 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3682 * @p: the task in question.
3683 * @policy: new policy.
3684 * @param: structure containing the new RT priority.
3686 * Just like sched_setscheduler, only don't bother checking if the
3687 * current context has permission. For example, this is needed in
3688 * stop_machine(): we create temporary high priority worker threads,
3689 * but our caller might not have that capability.
3691 * Return: 0 on success. An error code otherwise.
3693 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
3694 const struct sched_param *param)
3696 return _sched_setscheduler(p, policy, param, false);
3700 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
3702 struct sched_param lparam;
3703 struct task_struct *p;
3706 if (!param || pid < 0)
3708 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
3713 p = find_process_by_pid(pid);
3715 retval = sched_setscheduler(p, policy, &lparam);
3722 * Mimics kernel/events/core.c perf_copy_attr().
3724 static int sched_copy_attr(struct sched_attr __user *uattr,
3725 struct sched_attr *attr)
3730 if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0))
3734 * zero the full structure, so that a short copy will be nice.
3736 memset(attr, 0, sizeof(*attr));
3738 ret = get_user(size, &uattr->size);
3742 if (size > PAGE_SIZE) /* silly large */
3745 if (!size) /* abi compat */
3746 size = SCHED_ATTR_SIZE_VER0;
3748 if (size < SCHED_ATTR_SIZE_VER0)
3752 * If we're handed a bigger struct than we know of,
3753 * ensure all the unknown bits are 0 - i.e. new
3754 * user-space does not rely on any kernel feature
3755 * extensions we dont know about yet.
3757 if (size > sizeof(*attr)) {
3758 unsigned char __user *addr;
3759 unsigned char __user *end;
3762 addr = (void __user *)uattr + sizeof(*attr);
3763 end = (void __user *)uattr + size;
3765 for (; addr < end; addr++) {
3766 ret = get_user(val, addr);
3772 size = sizeof(*attr);
3775 ret = copy_from_user(attr, uattr, size);
3780 * XXX: do we want to be lenient like existing syscalls; or do we want
3781 * to be strict and return an error on out-of-bounds values?
3783 attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE);
3788 put_user(sizeof(*attr), &uattr->size);
3793 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3794 * @pid: the pid in question.
3795 * @policy: new policy.
3796 * @param: structure containing the new RT priority.
3798 * Return: 0 on success. An error code otherwise.
3800 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
3801 struct sched_param __user *, param)
3803 /* negative values for policy are not valid */
3807 return do_sched_setscheduler(pid, policy, param);
3811 * sys_sched_setparam - set/change the RT priority of a thread
3812 * @pid: the pid in question.
3813 * @param: structure containing the new RT priority.
3815 * Return: 0 on success. An error code otherwise.
3817 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
3819 return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
3823 * sys_sched_setattr - same as above, but with extended sched_attr
3824 * @pid: the pid in question.
3825 * @uattr: structure containing the extended parameters.
3826 * @flags: for future extension.
3828 SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
3829 unsigned int, flags)
3831 struct sched_attr attr;
3832 struct task_struct *p;
3835 if (!uattr || pid < 0 || flags)
3838 retval = sched_copy_attr(uattr, &attr);
3842 if ((int)attr.sched_policy < 0)
3847 p = find_process_by_pid(pid);
3849 retval = sched_setattr(p, &attr);
3856 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3857 * @pid: the pid in question.
3859 * Return: On success, the policy of the thread. Otherwise, a negative error
3862 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
3864 struct task_struct *p;
3872 p = find_process_by_pid(pid);
3874 retval = security_task_getscheduler(p);
3877 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
3884 * sys_sched_getparam - get the RT priority of a thread
3885 * @pid: the pid in question.
3886 * @param: structure containing the RT priority.
3888 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3891 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
3893 struct sched_param lp = { .sched_priority = 0 };
3894 struct task_struct *p;
3897 if (!param || pid < 0)
3901 p = find_process_by_pid(pid);
3906 retval = security_task_getscheduler(p);
3910 if (task_has_rt_policy(p))
3911 lp.sched_priority = p->rt_priority;
3915 * This one might sleep, we cannot do it with a spinlock held ...
3917 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
3926 static int sched_read_attr(struct sched_attr __user *uattr,
3927 struct sched_attr *attr,
3932 if (!access_ok(VERIFY_WRITE, uattr, usize))
3936 * If we're handed a smaller struct than we know of,
3937 * ensure all the unknown bits are 0 - i.e. old
3938 * user-space does not get uncomplete information.
3940 if (usize < sizeof(*attr)) {
3941 unsigned char *addr;
3944 addr = (void *)attr + usize;
3945 end = (void *)attr + sizeof(*attr);
3947 for (; addr < end; addr++) {
3955 ret = copy_to_user(uattr, attr, attr->size);
3963 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
3964 * @pid: the pid in question.
3965 * @uattr: structure containing the extended parameters.
3966 * @size: sizeof(attr) for fwd/bwd comp.
3967 * @flags: for future extension.
3969 SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
3970 unsigned int, size, unsigned int, flags)
3972 struct sched_attr attr = {
3973 .size = sizeof(struct sched_attr),
3975 struct task_struct *p;
3978 if (!uattr || pid < 0 || size > PAGE_SIZE ||
3979 size < SCHED_ATTR_SIZE_VER0 || flags)
3983 p = find_process_by_pid(pid);
3988 retval = security_task_getscheduler(p);
3992 attr.sched_policy = p->policy;
3993 if (p->sched_reset_on_fork)
3994 attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
3995 if (task_has_dl_policy(p))
3996 __getparam_dl(p, &attr);
3997 else if (task_has_rt_policy(p))
3998 attr.sched_priority = p->rt_priority;
4000 attr.sched_nice = task_nice(p);
4004 retval = sched_read_attr(uattr, &attr, size);
4012 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
4014 cpumask_var_t cpus_allowed, new_mask;
4015 struct task_struct *p;
4020 p = find_process_by_pid(pid);
4026 /* Prevent p going away */
4030 if (p->flags & PF_NO_SETAFFINITY) {
4034 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
4038 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
4040 goto out_free_cpus_allowed;
4043 if (!check_same_owner(p)) {
4045 if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
4047 goto out_free_new_mask;
4052 retval = security_task_setscheduler(p);
4054 goto out_free_new_mask;
4057 cpuset_cpus_allowed(p, cpus_allowed);
4058 cpumask_and(new_mask, in_mask, cpus_allowed);
4061 * Since bandwidth control happens on root_domain basis,
4062 * if admission test is enabled, we only admit -deadline
4063 * tasks allowed to run on all the CPUs in the task's
4067 if (task_has_dl_policy(p) && dl_bandwidth_enabled()) {
4069 if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) {
4072 goto out_free_new_mask;
4078 retval = set_cpus_allowed_ptr(p, new_mask);
4081 cpuset_cpus_allowed(p, cpus_allowed);
4082 if (!cpumask_subset(new_mask, cpus_allowed)) {
4084 * We must have raced with a concurrent cpuset
4085 * update. Just reset the cpus_allowed to the
4086 * cpuset's cpus_allowed
4088 cpumask_copy(new_mask, cpus_allowed);
4093 free_cpumask_var(new_mask);
4094 out_free_cpus_allowed:
4095 free_cpumask_var(cpus_allowed);
4101 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
4102 struct cpumask *new_mask)
4104 if (len < cpumask_size())
4105 cpumask_clear(new_mask);
4106 else if (len > cpumask_size())
4107 len = cpumask_size();
4109 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
4113 * sys_sched_setaffinity - set the cpu affinity of a process
4114 * @pid: pid of the process
4115 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4116 * @user_mask_ptr: user-space pointer to the new cpu mask
4118 * Return: 0 on success. An error code otherwise.
4120 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
4121 unsigned long __user *, user_mask_ptr)
4123 cpumask_var_t new_mask;
4126 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
4129 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
4131 retval = sched_setaffinity(pid, new_mask);
4132 free_cpumask_var(new_mask);
4136 long sched_getaffinity(pid_t pid, struct cpumask *mask)
4138 struct task_struct *p;
4139 unsigned long flags;
4145 p = find_process_by_pid(pid);
4149 retval = security_task_getscheduler(p);
4153 raw_spin_lock_irqsave(&p->pi_lock, flags);
4154 cpumask_and(mask, &p->cpus_allowed, cpu_active_mask);
4155 raw_spin_unlock_irqrestore(&p->pi_lock, flags);
4164 * sys_sched_getaffinity - get the cpu affinity of a process
4165 * @pid: pid of the process
4166 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4167 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4169 * Return: 0 on success. An error code otherwise.
4171 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
4172 unsigned long __user *, user_mask_ptr)
4177 if ((len * BITS_PER_BYTE) < nr_cpu_ids)
4179 if (len & (sizeof(unsigned long)-1))
4182 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
4185 ret = sched_getaffinity(pid, mask);
4187 size_t retlen = min_t(size_t, len, cpumask_size());
4189 if (copy_to_user(user_mask_ptr, mask, retlen))
4194 free_cpumask_var(mask);
4200 * sys_sched_yield - yield the current processor to other threads.
4202 * This function yields the current CPU to other tasks. If there are no
4203 * other threads running on this CPU then this function will return.
4207 SYSCALL_DEFINE0(sched_yield)
4209 struct rq *rq = this_rq_lock();
4211 schedstat_inc(rq, yld_count);
4212 current->sched_class->yield_task(rq);
4215 * Since we are going to call schedule() anyway, there's
4216 * no need to preempt or enable interrupts:
4218 __release(rq->lock);
4219 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
4220 do_raw_spin_unlock(&rq->lock);
4221 sched_preempt_enable_no_resched();
4228 static void __cond_resched(void)
4230 __preempt_count_add(PREEMPT_ACTIVE);
4232 __preempt_count_sub(PREEMPT_ACTIVE);
4235 int __sched _cond_resched(void)
4237 if (should_resched()) {
4243 EXPORT_SYMBOL(_cond_resched);
4246 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4247 * call schedule, and on return reacquire the lock.
4249 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4250 * operations here to prevent schedule() from being called twice (once via
4251 * spin_unlock(), once by hand).
4253 int __cond_resched_lock(spinlock_t *lock)
4255 int resched = should_resched();
4258 lockdep_assert_held(lock);
4260 if (spin_needbreak(lock) || resched) {
4271 EXPORT_SYMBOL(__cond_resched_lock);
4273 int __sched __cond_resched_softirq(void)
4275 BUG_ON(!in_softirq());
4277 if (should_resched()) {
4285 EXPORT_SYMBOL(__cond_resched_softirq);
4288 * yield - yield the current processor to other threads.
4290 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4292 * The scheduler is at all times free to pick the calling task as the most
4293 * eligible task to run, if removing the yield() call from your code breaks
4294 * it, its already broken.
4296 * Typical broken usage is:
4301 * where one assumes that yield() will let 'the other' process run that will
4302 * make event true. If the current task is a SCHED_FIFO task that will never
4303 * happen. Never use yield() as a progress guarantee!!
4305 * If you want to use yield() to wait for something, use wait_event().
4306 * If you want to use yield() to be 'nice' for others, use cond_resched().
4307 * If you still want to use yield(), do not!
4309 void __sched yield(void)
4311 set_current_state(TASK_RUNNING);
4314 EXPORT_SYMBOL(yield);
4317 * yield_to - yield the current processor to another thread in
4318 * your thread group, or accelerate that thread toward the
4319 * processor it's on.
4321 * @preempt: whether task preemption is allowed or not
4323 * It's the caller's job to ensure that the target task struct
4324 * can't go away on us before we can do any checks.
4327 * true (>0) if we indeed boosted the target task.
4328 * false (0) if we failed to boost the target.
4329 * -ESRCH if there's no task to yield to.
4331 int __sched yield_to(struct task_struct *p, bool preempt)
4333 struct task_struct *curr = current;
4334 struct rq *rq, *p_rq;
4335 unsigned long flags;
4338 local_irq_save(flags);
4344 * If we're the only runnable task on the rq and target rq also
4345 * has only one task, there's absolutely no point in yielding.
4347 if (rq->nr_running == 1 && p_rq->nr_running == 1) {
4352 double_rq_lock(rq, p_rq);
4353 if (task_rq(p) != p_rq) {
4354 double_rq_unlock(rq, p_rq);
4358 if (!curr->sched_class->yield_to_task)
4361 if (curr->sched_class != p->sched_class)
4364 if (task_running(p_rq, p) || p->state)
4367 yielded = curr->sched_class->yield_to_task(rq, p, preempt);
4369 schedstat_inc(rq, yld_count);
4371 * Make p's CPU reschedule; pick_next_entity takes care of
4374 if (preempt && rq != p_rq)
4379 double_rq_unlock(rq, p_rq);
4381 local_irq_restore(flags);
4388 EXPORT_SYMBOL_GPL(yield_to);
4391 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4392 * that process accounting knows that this is a task in IO wait state.
4394 void __sched io_schedule(void)
4396 struct rq *rq = raw_rq();
4398 delayacct_blkio_start();
4399 atomic_inc(&rq->nr_iowait);
4400 blk_flush_plug(current);
4401 current->in_iowait = 1;
4403 current->in_iowait = 0;
4404 atomic_dec(&rq->nr_iowait);
4405 delayacct_blkio_end();
4407 EXPORT_SYMBOL(io_schedule);
4409 long __sched io_schedule_timeout(long timeout)
4411 struct rq *rq = raw_rq();
4414 delayacct_blkio_start();
4415 atomic_inc(&rq->nr_iowait);
4416 blk_flush_plug(current);
4417 current->in_iowait = 1;
4418 ret = schedule_timeout(timeout);
4419 current->in_iowait = 0;
4420 atomic_dec(&rq->nr_iowait);
4421 delayacct_blkio_end();
4426 * sys_sched_get_priority_max - return maximum RT priority.
4427 * @policy: scheduling class.
4429 * Return: On success, this syscall returns the maximum
4430 * rt_priority that can be used by a given scheduling class.
4431 * On failure, a negative error code is returned.
4433 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
4440 ret = MAX_USER_RT_PRIO-1;
4442 case SCHED_DEADLINE:
4453 * sys_sched_get_priority_min - return minimum RT priority.
4454 * @policy: scheduling class.
4456 * Return: On success, this syscall returns the minimum
4457 * rt_priority that can be used by a given scheduling class.
4458 * On failure, a negative error code is returned.
4460 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
4469 case SCHED_DEADLINE:
4479 * sys_sched_rr_get_interval - return the default timeslice of a process.
4480 * @pid: pid of the process.
4481 * @interval: userspace pointer to the timeslice value.
4483 * this syscall writes the default timeslice value of a given process
4484 * into the user-space timespec buffer. A value of '0' means infinity.
4486 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4489 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
4490 struct timespec __user *, interval)
4492 struct task_struct *p;
4493 unsigned int time_slice;
4494 unsigned long flags;
4504 p = find_process_by_pid(pid);
4508 retval = security_task_getscheduler(p);
4512 rq = task_rq_lock(p, &flags);
4514 if (p->sched_class->get_rr_interval)
4515 time_slice = p->sched_class->get_rr_interval(rq, p);
4516 task_rq_unlock(rq, p, &flags);
4519 jiffies_to_timespec(time_slice, &t);
4520 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
4528 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
4530 void sched_show_task(struct task_struct *p)
4532 unsigned long free = 0;
4536 state = p->state ? __ffs(p->state) + 1 : 0;
4537 printk(KERN_INFO "%-15.15s %c", p->comm,
4538 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
4539 #if BITS_PER_LONG == 32
4540 if (state == TASK_RUNNING)
4541 printk(KERN_CONT " running ");
4543 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
4545 if (state == TASK_RUNNING)
4546 printk(KERN_CONT " running task ");
4548 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
4550 #ifdef CONFIG_DEBUG_STACK_USAGE
4551 free = stack_not_used(p);
4556 ppid = task_pid_nr(rcu_dereference(p->real_parent));
4558 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
4559 task_pid_nr(p), ppid,
4560 (unsigned long)task_thread_info(p)->flags);
4562 print_worker_info(KERN_INFO, p);
4563 show_stack(p, NULL);
4566 void show_state_filter(unsigned long state_filter)
4568 struct task_struct *g, *p;
4570 #if BITS_PER_LONG == 32
4572 " task PC stack pid father\n");
4575 " task PC stack pid father\n");
4578 for_each_process_thread(g, p) {
4580 * reset the NMI-timeout, listing all files on a slow
4581 * console might take a lot of time:
4583 touch_nmi_watchdog();
4584 if (!state_filter || (p->state & state_filter))
4588 touch_all_softlockup_watchdogs();
4590 #ifdef CONFIG_SCHED_DEBUG
4591 sysrq_sched_debug_show();
4595 * Only show locks if all tasks are dumped:
4598 debug_show_all_locks();
4601 void init_idle_bootup_task(struct task_struct *idle)
4603 idle->sched_class = &idle_sched_class;
4607 * init_idle - set up an idle thread for a given CPU
4608 * @idle: task in question
4609 * @cpu: cpu the idle task belongs to
4611 * NOTE: this function does not set the idle thread's NEED_RESCHED
4612 * flag, to make booting more robust.
4614 void init_idle(struct task_struct *idle, int cpu)
4616 struct rq *rq = cpu_rq(cpu);
4617 unsigned long flags;
4619 raw_spin_lock_irqsave(&rq->lock, flags);
4621 __sched_fork(0, idle);
4622 idle->state = TASK_RUNNING;
4623 idle->se.exec_start = sched_clock();
4625 do_set_cpus_allowed(idle, cpumask_of(cpu));
4627 * We're having a chicken and egg problem, even though we are
4628 * holding rq->lock, the cpu isn't yet set to this cpu so the
4629 * lockdep check in task_group() will fail.
4631 * Similar case to sched_fork(). / Alternatively we could
4632 * use task_rq_lock() here and obtain the other rq->lock.
4637 __set_task_cpu(idle, cpu);
4640 rq->curr = rq->idle = idle;
4641 idle->on_rq = TASK_ON_RQ_QUEUED;
4642 #if defined(CONFIG_SMP)
4645 raw_spin_unlock_irqrestore(&rq->lock, flags);
4647 /* Set the preempt count _outside_ the spinlocks! */
4648 init_idle_preempt_count(idle, cpu);
4651 * The idle tasks have their own, simple scheduling class:
4653 idle->sched_class = &idle_sched_class;
4654 ftrace_graph_init_idle_task(idle, cpu);
4655 vtime_init_idle(idle, cpu);
4656 #if defined(CONFIG_SMP)
4657 sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
4661 int cpuset_cpumask_can_shrink(const struct cpumask *cur,
4662 const struct cpumask *trial)
4664 int ret = 1, trial_cpus;
4665 struct dl_bw *cur_dl_b;
4666 unsigned long flags;
4668 if (!cpumask_weight(cur))
4671 rcu_read_lock_sched();
4672 cur_dl_b = dl_bw_of(cpumask_any(cur));
4673 trial_cpus = cpumask_weight(trial);
4675 raw_spin_lock_irqsave(&cur_dl_b->lock, flags);
4676 if (cur_dl_b->bw != -1 &&
4677 cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw)
4679 raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags);
4680 rcu_read_unlock_sched();
4685 int task_can_attach(struct task_struct *p,
4686 const struct cpumask *cs_cpus_allowed)
4691 * Kthreads which disallow setaffinity shouldn't be moved
4692 * to a new cpuset; we don't want to change their cpu
4693 * affinity and isolating such threads by their set of
4694 * allowed nodes is unnecessary. Thus, cpusets are not
4695 * applicable for such threads. This prevents checking for
4696 * success of set_cpus_allowed_ptr() on all attached tasks
4697 * before cpus_allowed may be changed.
4699 if (p->flags & PF_NO_SETAFFINITY) {
4705 if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span,
4707 unsigned int dest_cpu = cpumask_any_and(cpu_active_mask,
4712 unsigned long flags;
4714 rcu_read_lock_sched();
4715 dl_b = dl_bw_of(dest_cpu);
4716 raw_spin_lock_irqsave(&dl_b->lock, flags);
4717 cpus = dl_bw_cpus(dest_cpu);
4718 overflow = __dl_overflow(dl_b, cpus, 0, p->dl.dl_bw);
4723 * We reserve space for this task in the destination
4724 * root_domain, as we can't fail after this point.
4725 * We will free resources in the source root_domain
4726 * later on (see set_cpus_allowed_dl()).
4728 __dl_add(dl_b, p->dl.dl_bw);
4730 raw_spin_unlock_irqrestore(&dl_b->lock, flags);
4731 rcu_read_unlock_sched();
4741 * move_queued_task - move a queued task to new rq.
4743 * Returns (locked) new rq. Old rq's lock is released.
4745 static struct rq *move_queued_task(struct task_struct *p, int new_cpu)
4747 struct rq *rq = task_rq(p);
4749 lockdep_assert_held(&rq->lock);
4751 dequeue_task(rq, p, 0);
4752 p->on_rq = TASK_ON_RQ_MIGRATING;
4753 set_task_cpu(p, new_cpu);
4754 raw_spin_unlock(&rq->lock);
4756 rq = cpu_rq(new_cpu);
4758 raw_spin_lock(&rq->lock);
4759 BUG_ON(task_cpu(p) != new_cpu);
4760 p->on_rq = TASK_ON_RQ_QUEUED;
4761 enqueue_task(rq, p, 0);
4762 check_preempt_curr(rq, p, 0);
4767 void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
4769 if (p->sched_class && p->sched_class->set_cpus_allowed)
4770 p->sched_class->set_cpus_allowed(p, new_mask);
4772 cpumask_copy(&p->cpus_allowed, new_mask);
4773 p->nr_cpus_allowed = cpumask_weight(new_mask);
4777 * This is how migration works:
4779 * 1) we invoke migration_cpu_stop() on the target CPU using
4781 * 2) stopper starts to run (implicitly forcing the migrated thread
4783 * 3) it checks whether the migrated task is still in the wrong runqueue.
4784 * 4) if it's in the wrong runqueue then the migration thread removes
4785 * it and puts it into the right queue.
4786 * 5) stopper completes and stop_one_cpu() returns and the migration
4791 * Change a given task's CPU affinity. Migrate the thread to a
4792 * proper CPU and schedule it away if the CPU it's executing on
4793 * is removed from the allowed bitmask.
4795 * NOTE: the caller must have a valid reference to the task, the
4796 * task must not exit() & deallocate itself prematurely. The
4797 * call is not atomic; no spinlocks may be held.
4799 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
4801 unsigned long flags;
4803 unsigned int dest_cpu;
4806 rq = task_rq_lock(p, &flags);
4808 if (cpumask_equal(&p->cpus_allowed, new_mask))
4811 if (!cpumask_intersects(new_mask, cpu_active_mask)) {
4816 do_set_cpus_allowed(p, new_mask);
4818 /* Can the task run on the task's current CPU? If so, we're done */
4819 if (cpumask_test_cpu(task_cpu(p), new_mask))
4822 dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
4823 if (task_running(rq, p) || p->state == TASK_WAKING) {
4824 struct migration_arg arg = { p, dest_cpu };
4825 /* Need help from migration thread: drop lock and wait. */
4826 task_rq_unlock(rq, p, &flags);
4827 stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
4828 tlb_migrate_finish(p->mm);
4830 } else if (task_on_rq_queued(p))
4831 rq = move_queued_task(p, dest_cpu);
4833 task_rq_unlock(rq, p, &flags);
4837 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
4840 * Move (not current) task off this cpu, onto dest cpu. We're doing
4841 * this because either it can't run here any more (set_cpus_allowed()
4842 * away from this CPU, or CPU going down), or because we're
4843 * attempting to rebalance this task on exec (sched_exec).
4845 * So we race with normal scheduler movements, but that's OK, as long
4846 * as the task is no longer on this CPU.
4848 * Returns non-zero if task was successfully migrated.
4850 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
4855 if (unlikely(!cpu_active(dest_cpu)))
4858 rq = cpu_rq(src_cpu);
4860 raw_spin_lock(&p->pi_lock);
4861 raw_spin_lock(&rq->lock);
4862 /* Already moved. */
4863 if (task_cpu(p) != src_cpu)
4866 /* Affinity changed (again). */
4867 if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))
4871 * If we're not on a rq, the next wake-up will ensure we're
4874 if (task_on_rq_queued(p))
4875 rq = move_queued_task(p, dest_cpu);
4879 raw_spin_unlock(&rq->lock);
4880 raw_spin_unlock(&p->pi_lock);
4884 #ifdef CONFIG_NUMA_BALANCING
4885 /* Migrate current task p to target_cpu */
4886 int migrate_task_to(struct task_struct *p, int target_cpu)
4888 struct migration_arg arg = { p, target_cpu };
4889 int curr_cpu = task_cpu(p);
4891 if (curr_cpu == target_cpu)
4894 if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p)))
4897 /* TODO: This is not properly updating schedstats */
4899 trace_sched_move_numa(p, curr_cpu, target_cpu);
4900 return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg);
4904 * Requeue a task on a given node and accurately track the number of NUMA
4905 * tasks on the runqueues
4907 void sched_setnuma(struct task_struct *p, int nid)
4910 unsigned long flags;
4911 bool queued, running;
4913 rq = task_rq_lock(p, &flags);
4914 queued = task_on_rq_queued(p);
4915 running = task_current(rq, p);
4918 dequeue_task(rq, p, 0);
4920 put_prev_task(rq, p);
4922 p->numa_preferred_nid = nid;
4925 p->sched_class->set_curr_task(rq);
4927 enqueue_task(rq, p, 0);
4928 task_rq_unlock(rq, p, &flags);
4933 * migration_cpu_stop - this will be executed by a highprio stopper thread
4934 * and performs thread migration by bumping thread off CPU then
4935 * 'pushing' onto another runqueue.
4937 static int migration_cpu_stop(void *data)
4939 struct migration_arg *arg = data;
4942 * The original target cpu might have gone down and we might
4943 * be on another cpu but it doesn't matter.
4945 local_irq_disable();
4947 * We need to explicitly wake pending tasks before running
4948 * __migrate_task() such that we will not miss enforcing cpus_allowed
4949 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
4951 sched_ttwu_pending();
4952 __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu);
4957 #ifdef CONFIG_HOTPLUG_CPU
4960 * Ensures that the idle task is using init_mm right before its cpu goes
4963 void idle_task_exit(void)
4965 struct mm_struct *mm = current->active_mm;
4967 BUG_ON(cpu_online(smp_processor_id()));
4969 if (mm != &init_mm) {
4970 switch_mm(mm, &init_mm, current);
4971 finish_arch_post_lock_switch();
4977 * Since this CPU is going 'away' for a while, fold any nr_active delta
4978 * we might have. Assumes we're called after migrate_tasks() so that the
4979 * nr_active count is stable.
4981 * Also see the comment "Global load-average calculations".
4983 static void calc_load_migrate(struct rq *rq)
4985 long delta = calc_load_fold_active(rq);
4987 atomic_long_add(delta, &calc_load_tasks);
4990 static void put_prev_task_fake(struct rq *rq, struct task_struct *prev)
4994 static const struct sched_class fake_sched_class = {
4995 .put_prev_task = put_prev_task_fake,
4998 static struct task_struct fake_task = {
5000 * Avoid pull_{rt,dl}_task()
5002 .prio = MAX_PRIO + 1,
5003 .sched_class = &fake_sched_class,
5007 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5008 * try_to_wake_up()->select_task_rq().
5010 * Called with rq->lock held even though we'er in stop_machine() and
5011 * there's no concurrency possible, we hold the required locks anyway
5012 * because of lock validation efforts.
5014 static void migrate_tasks(unsigned int dead_cpu)
5016 struct rq *rq = cpu_rq(dead_cpu);
5017 struct task_struct *next, *stop = rq->stop;
5021 * Fudge the rq selection such that the below task selection loop
5022 * doesn't get stuck on the currently eligible stop task.
5024 * We're currently inside stop_machine() and the rq is either stuck
5025 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5026 * either way we should never end up calling schedule() until we're
5032 * put_prev_task() and pick_next_task() sched
5033 * class method both need to have an up-to-date
5034 * value of rq->clock[_task]
5036 update_rq_clock(rq);
5040 * There's this thread running, bail when that's the only
5043 if (rq->nr_running == 1)
5046 next = pick_next_task(rq, &fake_task);
5048 next->sched_class->put_prev_task(rq, next);
5050 /* Find suitable destination for @next, with force if needed. */
5051 dest_cpu = select_fallback_rq(dead_cpu, next);
5052 raw_spin_unlock(&rq->lock);
5054 __migrate_task(next, dead_cpu, dest_cpu);
5056 raw_spin_lock(&rq->lock);
5062 #endif /* CONFIG_HOTPLUG_CPU */
5064 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5066 static struct ctl_table sd_ctl_dir[] = {
5068 .procname = "sched_domain",
5074 static struct ctl_table sd_ctl_root[] = {
5076 .procname = "kernel",
5078 .child = sd_ctl_dir,
5083 static struct ctl_table *sd_alloc_ctl_entry(int n)
5085 struct ctl_table *entry =
5086 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
5091 static void sd_free_ctl_entry(struct ctl_table **tablep)
5093 struct ctl_table *entry;
5096 * In the intermediate directories, both the child directory and
5097 * procname are dynamically allocated and could fail but the mode
5098 * will always be set. In the lowest directory the names are
5099 * static strings and all have proc handlers.
5101 for (entry = *tablep; entry->mode; entry++) {
5103 sd_free_ctl_entry(&entry->child);
5104 if (entry->proc_handler == NULL)
5105 kfree(entry->procname);
5112 static int min_load_idx = 0;
5113 static int max_load_idx = CPU_LOAD_IDX_MAX-1;
5116 set_table_entry(struct ctl_table *entry,
5117 const char *procname, void *data, int maxlen,
5118 umode_t mode, proc_handler *proc_handler,
5121 entry->procname = procname;
5123 entry->maxlen = maxlen;
5125 entry->proc_handler = proc_handler;
5128 entry->extra1 = &min_load_idx;
5129 entry->extra2 = &max_load_idx;
5133 static struct ctl_table *
5134 sd_alloc_ctl_domain_table(struct sched_domain *sd)
5136 struct ctl_table *table = sd_alloc_ctl_entry(14);
5141 set_table_entry(&table[0], "min_interval", &sd->min_interval,
5142 sizeof(long), 0644, proc_doulongvec_minmax, false);
5143 set_table_entry(&table[1], "max_interval", &sd->max_interval,
5144 sizeof(long), 0644, proc_doulongvec_minmax, false);
5145 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
5146 sizeof(int), 0644, proc_dointvec_minmax, true);
5147 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
5148 sizeof(int), 0644, proc_dointvec_minmax, true);
5149 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
5150 sizeof(int), 0644, proc_dointvec_minmax, true);
5151 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
5152 sizeof(int), 0644, proc_dointvec_minmax, true);
5153 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
5154 sizeof(int), 0644, proc_dointvec_minmax, true);
5155 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
5156 sizeof(int), 0644, proc_dointvec_minmax, false);
5157 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
5158 sizeof(int), 0644, proc_dointvec_minmax, false);
5159 set_table_entry(&table[9], "cache_nice_tries",
5160 &sd->cache_nice_tries,
5161 sizeof(int), 0644, proc_dointvec_minmax, false);
5162 set_table_entry(&table[10], "flags", &sd->flags,
5163 sizeof(int), 0644, proc_dointvec_minmax, false);
5164 set_table_entry(&table[11], "max_newidle_lb_cost",
5165 &sd->max_newidle_lb_cost,
5166 sizeof(long), 0644, proc_doulongvec_minmax, false);
5167 set_table_entry(&table[12], "name", sd->name,
5168 CORENAME_MAX_SIZE, 0444, proc_dostring, false);
5169 /* &table[13] is terminator */
5174 static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu)
5176 struct ctl_table *entry, *table;
5177 struct sched_domain *sd;
5178 int domain_num = 0, i;
5181 for_each_domain(cpu, sd)
5183 entry = table = sd_alloc_ctl_entry(domain_num + 1);
5188 for_each_domain(cpu, sd) {
5189 snprintf(buf, 32, "domain%d", i);
5190 entry->procname = kstrdup(buf, GFP_KERNEL);
5192 entry->child = sd_alloc_ctl_domain_table(sd);
5199 static struct ctl_table_header *sd_sysctl_header;
5200 static void register_sched_domain_sysctl(void)
5202 int i, cpu_num = num_possible_cpus();
5203 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
5206 WARN_ON(sd_ctl_dir[0].child);
5207 sd_ctl_dir[0].child = entry;
5212 for_each_possible_cpu(i) {
5213 snprintf(buf, 32, "cpu%d", i);
5214 entry->procname = kstrdup(buf, GFP_KERNEL);
5216 entry->child = sd_alloc_ctl_cpu_table(i);
5220 WARN_ON(sd_sysctl_header);
5221 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
5224 /* may be called multiple times per register */
5225 static void unregister_sched_domain_sysctl(void)
5227 if (sd_sysctl_header)
5228 unregister_sysctl_table(sd_sysctl_header);
5229 sd_sysctl_header = NULL;
5230 if (sd_ctl_dir[0].child)
5231 sd_free_ctl_entry(&sd_ctl_dir[0].child);
5234 static void register_sched_domain_sysctl(void)
5237 static void unregister_sched_domain_sysctl(void)
5242 static void set_rq_online(struct rq *rq)
5245 const struct sched_class *class;
5247 cpumask_set_cpu(rq->cpu, rq->rd->online);
5250 for_each_class(class) {
5251 if (class->rq_online)
5252 class->rq_online(rq);
5257 static void set_rq_offline(struct rq *rq)
5260 const struct sched_class *class;
5262 for_each_class(class) {
5263 if (class->rq_offline)
5264 class->rq_offline(rq);
5267 cpumask_clear_cpu(rq->cpu, rq->rd->online);
5273 * migration_call - callback that gets triggered when a CPU is added.
5274 * Here we can start up the necessary migration thread for the new CPU.
5277 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
5279 int cpu = (long)hcpu;
5280 unsigned long flags;
5281 struct rq *rq = cpu_rq(cpu);
5283 switch (action & ~CPU_TASKS_FROZEN) {
5285 case CPU_UP_PREPARE:
5286 rq->calc_load_update = calc_load_update;
5290 /* Update our root-domain */
5291 raw_spin_lock_irqsave(&rq->lock, flags);
5293 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5297 raw_spin_unlock_irqrestore(&rq->lock, flags);
5300 #ifdef CONFIG_HOTPLUG_CPU
5302 sched_ttwu_pending();
5303 /* Update our root-domain */
5304 raw_spin_lock_irqsave(&rq->lock, flags);
5306 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
5310 BUG_ON(rq->nr_running != 1); /* the migration thread */
5311 raw_spin_unlock_irqrestore(&rq->lock, flags);
5315 calc_load_migrate(rq);
5320 update_max_interval();
5326 * Register at high priority so that task migration (migrate_all_tasks)
5327 * happens before everything else. This has to be lower priority than
5328 * the notifier in the perf_event subsystem, though.
5330 static struct notifier_block migration_notifier = {
5331 .notifier_call = migration_call,
5332 .priority = CPU_PRI_MIGRATION,
5335 static void __cpuinit set_cpu_rq_start_time(void)
5337 int cpu = smp_processor_id();
5338 struct rq *rq = cpu_rq(cpu);
5339 rq->age_stamp = sched_clock_cpu(cpu);
5342 static int sched_cpu_active(struct notifier_block *nfb,
5343 unsigned long action, void *hcpu)
5345 switch (action & ~CPU_TASKS_FROZEN) {
5347 set_cpu_rq_start_time();
5349 case CPU_DOWN_FAILED:
5350 set_cpu_active((long)hcpu, true);
5357 static int sched_cpu_inactive(struct notifier_block *nfb,
5358 unsigned long action, void *hcpu)
5360 unsigned long flags;
5361 long cpu = (long)hcpu;
5364 switch (action & ~CPU_TASKS_FROZEN) {
5365 case CPU_DOWN_PREPARE:
5366 set_cpu_active(cpu, false);
5368 /* explicitly allow suspend */
5369 if (!(action & CPU_TASKS_FROZEN)) {
5373 rcu_read_lock_sched();
5374 dl_b = dl_bw_of(cpu);
5376 raw_spin_lock_irqsave(&dl_b->lock, flags);
5377 cpus = dl_bw_cpus(cpu);
5378 overflow = __dl_overflow(dl_b, cpus, 0, 0);
5379 raw_spin_unlock_irqrestore(&dl_b->lock, flags);
5381 rcu_read_unlock_sched();
5384 return notifier_from_errno(-EBUSY);
5392 static int __init migration_init(void)
5394 void *cpu = (void *)(long)smp_processor_id();
5397 /* Initialize migration for the boot CPU */
5398 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
5399 BUG_ON(err == NOTIFY_BAD);
5400 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5401 register_cpu_notifier(&migration_notifier);
5403 /* Register cpu active notifiers */
5404 cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
5405 cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
5409 early_initcall(migration_init);
5414 static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */
5416 #ifdef CONFIG_SCHED_DEBUG
5418 static __read_mostly int sched_debug_enabled;
5420 static int __init sched_debug_setup(char *str)
5422 sched_debug_enabled = 1;
5426 early_param("sched_debug", sched_debug_setup);
5428 static inline bool sched_debug(void)
5430 return sched_debug_enabled;
5433 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
5434 struct cpumask *groupmask)
5436 struct sched_group *group = sd->groups;
5439 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
5440 cpumask_clear(groupmask);
5442 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
5444 if (!(sd->flags & SD_LOAD_BALANCE)) {
5445 printk("does not load-balance\n");
5447 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
5452 printk(KERN_CONT "span %s level %s\n", str, sd->name);
5454 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
5455 printk(KERN_ERR "ERROR: domain->span does not contain "
5458 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
5459 printk(KERN_ERR "ERROR: domain->groups does not contain"
5463 printk(KERN_DEBUG "%*s groups:", level + 1, "");
5467 printk(KERN_ERR "ERROR: group is NULL\n");
5472 * Even though we initialize ->capacity to something semi-sane,
5473 * we leave capacity_orig unset. This allows us to detect if
5474 * domain iteration is still funny without causing /0 traps.
5476 if (!group->sgc->capacity_orig) {
5477 printk(KERN_CONT "\n");
5478 printk(KERN_ERR "ERROR: domain->cpu_capacity not set\n");
5482 if (!cpumask_weight(sched_group_cpus(group))) {
5483 printk(KERN_CONT "\n");
5484 printk(KERN_ERR "ERROR: empty group\n");
5488 if (!(sd->flags & SD_OVERLAP) &&
5489 cpumask_intersects(groupmask, sched_group_cpus(group))) {
5490 printk(KERN_CONT "\n");
5491 printk(KERN_ERR "ERROR: repeated CPUs\n");
5495 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
5497 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
5499 printk(KERN_CONT " %s", str);
5500 if (group->sgc->capacity != SCHED_CAPACITY_SCALE) {
5501 printk(KERN_CONT " (cpu_capacity = %d)",
5502 group->sgc->capacity);
5505 group = group->next;
5506 } while (group != sd->groups);
5507 printk(KERN_CONT "\n");
5509 if (!cpumask_equal(sched_domain_span(sd), groupmask))
5510 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
5513 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
5514 printk(KERN_ERR "ERROR: parent span is not a superset "
5515 "of domain->span\n");
5519 static void sched_domain_debug(struct sched_domain *sd, int cpu)
5523 if (!sched_debug_enabled)
5527 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
5531 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
5534 if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
5542 #else /* !CONFIG_SCHED_DEBUG */
5543 # define sched_domain_debug(sd, cpu) do { } while (0)
5544 static inline bool sched_debug(void)
5548 #endif /* CONFIG_SCHED_DEBUG */
5550 static int sd_degenerate(struct sched_domain *sd)
5552 if (cpumask_weight(sched_domain_span(sd)) == 1)
5555 /* Following flags need at least 2 groups */
5556 if (sd->flags & (SD_LOAD_BALANCE |
5557 SD_BALANCE_NEWIDLE |
5560 SD_SHARE_CPUCAPACITY |
5561 SD_SHARE_PKG_RESOURCES |
5562 SD_SHARE_POWERDOMAIN)) {
5563 if (sd->groups != sd->groups->next)
5567 /* Following flags don't use groups */
5568 if (sd->flags & (SD_WAKE_AFFINE))
5575 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
5577 unsigned long cflags = sd->flags, pflags = parent->flags;
5579 if (sd_degenerate(parent))
5582 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
5585 /* Flags needing groups don't count if only 1 group in parent */
5586 if (parent->groups == parent->groups->next) {
5587 pflags &= ~(SD_LOAD_BALANCE |
5588 SD_BALANCE_NEWIDLE |
5591 SD_SHARE_CPUCAPACITY |
5592 SD_SHARE_PKG_RESOURCES |
5594 SD_SHARE_POWERDOMAIN);
5595 if (nr_node_ids == 1)
5596 pflags &= ~SD_SERIALIZE;
5598 if (~cflags & pflags)
5604 static void free_rootdomain(struct rcu_head *rcu)
5606 struct root_domain *rd = container_of(rcu, struct root_domain, rcu);
5608 cpupri_cleanup(&rd->cpupri);
5609 cpudl_cleanup(&rd->cpudl);
5610 free_cpumask_var(rd->dlo_mask);
5611 free_cpumask_var(rd->rto_mask);
5612 free_cpumask_var(rd->online);
5613 free_cpumask_var(rd->span);
5617 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
5619 struct root_domain *old_rd = NULL;
5620 unsigned long flags;
5622 raw_spin_lock_irqsave(&rq->lock, flags);
5627 if (cpumask_test_cpu(rq->cpu, old_rd->online))
5630 cpumask_clear_cpu(rq->cpu, old_rd->span);
5633 * If we dont want to free the old_rd yet then
5634 * set old_rd to NULL to skip the freeing later
5637 if (!atomic_dec_and_test(&old_rd->refcount))
5641 atomic_inc(&rd->refcount);
5644 cpumask_set_cpu(rq->cpu, rd->span);
5645 if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
5648 raw_spin_unlock_irqrestore(&rq->lock, flags);
5651 call_rcu_sched(&old_rd->rcu, free_rootdomain);
5654 static int init_rootdomain(struct root_domain *rd)
5656 memset(rd, 0, sizeof(*rd));
5658 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
5660 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
5662 if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL))
5664 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
5667 init_dl_bw(&rd->dl_bw);
5668 if (cpudl_init(&rd->cpudl) != 0)
5671 if (cpupri_init(&rd->cpupri) != 0)
5676 free_cpumask_var(rd->rto_mask);
5678 free_cpumask_var(rd->dlo_mask);
5680 free_cpumask_var(rd->online);
5682 free_cpumask_var(rd->span);
5688 * By default the system creates a single root-domain with all cpus as
5689 * members (mimicking the global state we have today).
5691 struct root_domain def_root_domain;
5693 static void init_defrootdomain(void)
5695 init_rootdomain(&def_root_domain);
5697 atomic_set(&def_root_domain.refcount, 1);
5700 static struct root_domain *alloc_rootdomain(void)
5702 struct root_domain *rd;
5704 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
5708 if (init_rootdomain(rd) != 0) {
5716 static void free_sched_groups(struct sched_group *sg, int free_sgc)
5718 struct sched_group *tmp, *first;
5727 if (free_sgc && atomic_dec_and_test(&sg->sgc->ref))
5732 } while (sg != first);
5735 static void free_sched_domain(struct rcu_head *rcu)
5737 struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
5740 * If its an overlapping domain it has private groups, iterate and
5743 if (sd->flags & SD_OVERLAP) {
5744 free_sched_groups(sd->groups, 1);
5745 } else if (atomic_dec_and_test(&sd->groups->ref)) {
5746 kfree(sd->groups->sgc);
5752 static void destroy_sched_domain(struct sched_domain *sd, int cpu)
5754 call_rcu(&sd->rcu, free_sched_domain);
5757 static void destroy_sched_domains(struct sched_domain *sd, int cpu)
5759 for (; sd; sd = sd->parent)
5760 destroy_sched_domain(sd, cpu);
5764 * Keep a special pointer to the highest sched_domain that has
5765 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5766 * allows us to avoid some pointer chasing select_idle_sibling().
5768 * Also keep a unique ID per domain (we use the first cpu number in
5769 * the cpumask of the domain), this allows us to quickly tell if
5770 * two cpus are in the same cache domain, see cpus_share_cache().
5772 DEFINE_PER_CPU(struct sched_domain *, sd_llc);
5773 DEFINE_PER_CPU(int, sd_llc_size);
5774 DEFINE_PER_CPU(int, sd_llc_id);
5775 DEFINE_PER_CPU(struct sched_domain *, sd_numa);
5776 DEFINE_PER_CPU(struct sched_domain *, sd_busy);
5777 DEFINE_PER_CPU(struct sched_domain *, sd_asym);
5779 static void update_top_cache_domain(int cpu)
5781 struct sched_domain *sd;
5782 struct sched_domain *busy_sd = NULL;
5786 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
5788 id = cpumask_first(sched_domain_span(sd));
5789 size = cpumask_weight(sched_domain_span(sd));
5790 busy_sd = sd->parent; /* sd_busy */
5792 rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd);
5794 rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
5795 per_cpu(sd_llc_size, cpu) = size;
5796 per_cpu(sd_llc_id, cpu) = id;
5798 sd = lowest_flag_domain(cpu, SD_NUMA);
5799 rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
5801 sd = highest_flag_domain(cpu, SD_ASYM_PACKING);
5802 rcu_assign_pointer(per_cpu(sd_asym, cpu), sd);
5806 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5807 * hold the hotplug lock.
5810 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
5812 struct rq *rq = cpu_rq(cpu);
5813 struct sched_domain *tmp;
5815 /* Remove the sched domains which do not contribute to scheduling. */
5816 for (tmp = sd; tmp; ) {
5817 struct sched_domain *parent = tmp->parent;
5821 if (sd_parent_degenerate(tmp, parent)) {
5822 tmp->parent = parent->parent;
5824 parent->parent->child = tmp;
5826 * Transfer SD_PREFER_SIBLING down in case of a
5827 * degenerate parent; the spans match for this
5828 * so the property transfers.
5830 if (parent->flags & SD_PREFER_SIBLING)
5831 tmp->flags |= SD_PREFER_SIBLING;
5832 destroy_sched_domain(parent, cpu);
5837 if (sd && sd_degenerate(sd)) {
5840 destroy_sched_domain(tmp, cpu);
5845 sched_domain_debug(sd, cpu);
5847 rq_attach_root(rq, rd);
5849 rcu_assign_pointer(rq->sd, sd);
5850 destroy_sched_domains(tmp, cpu);
5852 update_top_cache_domain(cpu);
5855 /* cpus with isolated domains */
5856 static cpumask_var_t cpu_isolated_map;
5858 /* Setup the mask of cpus configured for isolated domains */
5859 static int __init isolated_cpu_setup(char *str)
5861 alloc_bootmem_cpumask_var(&cpu_isolated_map);
5862 cpulist_parse(str, cpu_isolated_map);
5866 __setup("isolcpus=", isolated_cpu_setup);
5869 struct sched_domain ** __percpu sd;
5870 struct root_domain *rd;
5881 * Build an iteration mask that can exclude certain CPUs from the upwards
5884 * Asymmetric node setups can result in situations where the domain tree is of
5885 * unequal depth, make sure to skip domains that already cover the entire
5888 * In that case build_sched_domains() will have terminated the iteration early
5889 * and our sibling sd spans will be empty. Domains should always include the
5890 * cpu they're built on, so check that.
5893 static void build_group_mask(struct sched_domain *sd, struct sched_group *sg)
5895 const struct cpumask *span = sched_domain_span(sd);
5896 struct sd_data *sdd = sd->private;
5897 struct sched_domain *sibling;
5900 for_each_cpu(i, span) {
5901 sibling = *per_cpu_ptr(sdd->sd, i);
5902 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
5905 cpumask_set_cpu(i, sched_group_mask(sg));
5910 * Return the canonical balance cpu for this group, this is the first cpu
5911 * of this group that's also in the iteration mask.
5913 int group_balance_cpu(struct sched_group *sg)
5915 return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg));
5919 build_overlap_sched_groups(struct sched_domain *sd, int cpu)
5921 struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
5922 const struct cpumask *span = sched_domain_span(sd);
5923 struct cpumask *covered = sched_domains_tmpmask;
5924 struct sd_data *sdd = sd->private;
5925 struct sched_domain *sibling;
5928 cpumask_clear(covered);
5930 for_each_cpu(i, span) {
5931 struct cpumask *sg_span;
5933 if (cpumask_test_cpu(i, covered))
5936 sibling = *per_cpu_ptr(sdd->sd, i);
5938 /* See the comment near build_group_mask(). */
5939 if (!cpumask_test_cpu(i, sched_domain_span(sibling)))
5942 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
5943 GFP_KERNEL, cpu_to_node(cpu));
5948 sg_span = sched_group_cpus(sg);
5950 cpumask_copy(sg_span, sched_domain_span(sibling->child));
5952 cpumask_set_cpu(i, sg_span);
5954 cpumask_or(covered, covered, sg_span);
5956 sg->sgc = *per_cpu_ptr(sdd->sgc, i);
5957 if (atomic_inc_return(&sg->sgc->ref) == 1)
5958 build_group_mask(sd, sg);
5961 * Initialize sgc->capacity such that even if we mess up the
5962 * domains and no possible iteration will get us here, we won't
5965 sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);
5966 sg->sgc->capacity_orig = sg->sgc->capacity;
5969 * Make sure the first group of this domain contains the
5970 * canonical balance cpu. Otherwise the sched_domain iteration
5971 * breaks. See update_sg_lb_stats().
5973 if ((!groups && cpumask_test_cpu(cpu, sg_span)) ||
5974 group_balance_cpu(sg) == cpu)
5984 sd->groups = groups;
5989 free_sched_groups(first, 0);
5994 static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
5996 struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
5997 struct sched_domain *child = sd->child;
6000 cpu = cpumask_first(sched_domain_span(child));
6003 *sg = *per_cpu_ptr(sdd->sg, cpu);
6004 (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu);
6005 atomic_set(&(*sg)->sgc->ref, 1); /* for claim_allocations */
6012 * build_sched_groups will build a circular linked list of the groups
6013 * covered by the given span, and will set each group's ->cpumask correctly,
6014 * and ->cpu_capacity to 0.
6016 * Assumes the sched_domain tree is fully constructed
6019 build_sched_groups(struct sched_domain *sd, int cpu)
6021 struct sched_group *first = NULL, *last = NULL;
6022 struct sd_data *sdd = sd->private;
6023 const struct cpumask *span = sched_domain_span(sd);
6024 struct cpumask *covered;
6027 get_group(cpu, sdd, &sd->groups);
6028 atomic_inc(&sd->groups->ref);
6030 if (cpu != cpumask_first(span))
6033 lockdep_assert_held(&sched_domains_mutex);
6034 covered = sched_domains_tmpmask;
6036 cpumask_clear(covered);
6038 for_each_cpu(i, span) {
6039 struct sched_group *sg;
6042 if (cpumask_test_cpu(i, covered))
6045 group = get_group(i, sdd, &sg);
6046 cpumask_setall(sched_group_mask(sg));
6048 for_each_cpu(j, span) {
6049 if (get_group(j, sdd, NULL) != group)
6052 cpumask_set_cpu(j, covered);
6053 cpumask_set_cpu(j, sched_group_cpus(sg));
6068 * Initialize sched groups cpu_capacity.
6070 * cpu_capacity indicates the capacity of sched group, which is used while
6071 * distributing the load between different sched groups in a sched domain.
6072 * Typically cpu_capacity for all the groups in a sched domain will be same
6073 * unless there are asymmetries in the topology. If there are asymmetries,
6074 * group having more cpu_capacity will pickup more load compared to the
6075 * group having less cpu_capacity.
6077 static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
6079 struct sched_group *sg = sd->groups;
6084 sg->group_weight = cpumask_weight(sched_group_cpus(sg));
6086 } while (sg != sd->groups);
6088 if (cpu != group_balance_cpu(sg))
6091 update_group_capacity(sd, cpu);
6092 atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight);
6096 * Initializers for schedule domains
6097 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6100 static int default_relax_domain_level = -1;
6101 int sched_domain_level_max;
6103 static int __init setup_relax_domain_level(char *str)
6105 if (kstrtoint(str, 0, &default_relax_domain_level))
6106 pr_warn("Unable to set relax_domain_level\n");
6110 __setup("relax_domain_level=", setup_relax_domain_level);
6112 static void set_domain_attribute(struct sched_domain *sd,
6113 struct sched_domain_attr *attr)
6117 if (!attr || attr->relax_domain_level < 0) {
6118 if (default_relax_domain_level < 0)
6121 request = default_relax_domain_level;
6123 request = attr->relax_domain_level;
6124 if (request < sd->level) {
6125 /* turn off idle balance on this domain */
6126 sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6128 /* turn on idle balance on this domain */
6129 sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
6133 static void __sdt_free(const struct cpumask *cpu_map);
6134 static int __sdt_alloc(const struct cpumask *cpu_map);
6136 static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
6137 const struct cpumask *cpu_map)
6141 if (!atomic_read(&d->rd->refcount))
6142 free_rootdomain(&d->rd->rcu); /* fall through */
6144 free_percpu(d->sd); /* fall through */
6146 __sdt_free(cpu_map); /* fall through */
6152 static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
6153 const struct cpumask *cpu_map)
6155 memset(d, 0, sizeof(*d));
6157 if (__sdt_alloc(cpu_map))
6158 return sa_sd_storage;
6159 d->sd = alloc_percpu(struct sched_domain *);
6161 return sa_sd_storage;
6162 d->rd = alloc_rootdomain();
6165 return sa_rootdomain;
6169 * NULL the sd_data elements we've used to build the sched_domain and
6170 * sched_group structure so that the subsequent __free_domain_allocs()
6171 * will not free the data we're using.
6173 static void claim_allocations(int cpu, struct sched_domain *sd)
6175 struct sd_data *sdd = sd->private;
6177 WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
6178 *per_cpu_ptr(sdd->sd, cpu) = NULL;
6180 if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
6181 *per_cpu_ptr(sdd->sg, cpu) = NULL;
6183 if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref))
6184 *per_cpu_ptr(sdd->sgc, cpu) = NULL;
6188 static int sched_domains_numa_levels;
6189 enum numa_topology_type sched_numa_topology_type;
6190 static int *sched_domains_numa_distance;
6191 int sched_max_numa_distance;
6192 static struct cpumask ***sched_domains_numa_masks;
6193 static int sched_domains_curr_level;
6197 * SD_flags allowed in topology descriptions.
6199 * SD_SHARE_CPUCAPACITY - describes SMT topologies
6200 * SD_SHARE_PKG_RESOURCES - describes shared caches
6201 * SD_NUMA - describes NUMA topologies
6202 * SD_SHARE_POWERDOMAIN - describes shared power domain
6205 * SD_ASYM_PACKING - describes SMT quirks
6207 #define TOPOLOGY_SD_FLAGS \
6208 (SD_SHARE_CPUCAPACITY | \
6209 SD_SHARE_PKG_RESOURCES | \
6212 SD_SHARE_POWERDOMAIN)
6214 static struct sched_domain *
6215 sd_init(struct sched_domain_topology_level *tl, int cpu)
6217 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
6218 int sd_weight, sd_flags = 0;
6222 * Ugly hack to pass state to sd_numa_mask()...
6224 sched_domains_curr_level = tl->numa_level;
6227 sd_weight = cpumask_weight(tl->mask(cpu));
6230 sd_flags = (*tl->sd_flags)();
6231 if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS,
6232 "wrong sd_flags in topology description\n"))
6233 sd_flags &= ~TOPOLOGY_SD_FLAGS;
6235 *sd = (struct sched_domain){
6236 .min_interval = sd_weight,
6237 .max_interval = 2*sd_weight,
6239 .imbalance_pct = 125,
6241 .cache_nice_tries = 0,
6248 .flags = 1*SD_LOAD_BALANCE
6249 | 1*SD_BALANCE_NEWIDLE
6254 | 0*SD_SHARE_CPUCAPACITY
6255 | 0*SD_SHARE_PKG_RESOURCES
6257 | 0*SD_PREFER_SIBLING
6262 .last_balance = jiffies,
6263 .balance_interval = sd_weight,
6265 .max_newidle_lb_cost = 0,
6266 .next_decay_max_lb_cost = jiffies,
6267 #ifdef CONFIG_SCHED_DEBUG
6273 * Convert topological properties into behaviour.
6276 if (sd->flags & SD_SHARE_CPUCAPACITY) {
6277 sd->imbalance_pct = 110;
6278 sd->smt_gain = 1178; /* ~15% */
6280 } else if (sd->flags & SD_SHARE_PKG_RESOURCES) {
6281 sd->imbalance_pct = 117;
6282 sd->cache_nice_tries = 1;
6286 } else if (sd->flags & SD_NUMA) {
6287 sd->cache_nice_tries = 2;
6291 sd->flags |= SD_SERIALIZE;
6292 if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) {
6293 sd->flags &= ~(SD_BALANCE_EXEC |
6300 sd->flags |= SD_PREFER_SIBLING;
6301 sd->cache_nice_tries = 1;
6306 sd->private = &tl->data;
6312 * Topology list, bottom-up.
6314 static struct sched_domain_topology_level default_topology[] = {
6315 #ifdef CONFIG_SCHED_SMT
6316 { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
6318 #ifdef CONFIG_SCHED_MC
6319 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
6321 { cpu_cpu_mask, SD_INIT_NAME(DIE) },
6325 struct sched_domain_topology_level *sched_domain_topology = default_topology;
6327 #define for_each_sd_topology(tl) \
6328 for (tl = sched_domain_topology; tl->mask; tl++)
6330 void set_sched_topology(struct sched_domain_topology_level *tl)
6332 sched_domain_topology = tl;
6337 static const struct cpumask *sd_numa_mask(int cpu)
6339 return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)];
6342 static void sched_numa_warn(const char *str)
6344 static int done = false;
6352 printk(KERN_WARNING "ERROR: %s\n\n", str);
6354 for (i = 0; i < nr_node_ids; i++) {
6355 printk(KERN_WARNING " ");
6356 for (j = 0; j < nr_node_ids; j++)
6357 printk(KERN_CONT "%02d ", node_distance(i,j));
6358 printk(KERN_CONT "\n");
6360 printk(KERN_WARNING "\n");
6363 bool find_numa_distance(int distance)
6367 if (distance == node_distance(0, 0))
6370 for (i = 0; i < sched_domains_numa_levels; i++) {
6371 if (sched_domains_numa_distance[i] == distance)
6379 * A system can have three types of NUMA topology:
6380 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
6381 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
6382 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
6384 * The difference between a glueless mesh topology and a backplane
6385 * topology lies in whether communication between not directly
6386 * connected nodes goes through intermediary nodes (where programs
6387 * could run), or through backplane controllers. This affects
6388 * placement of programs.
6390 * The type of topology can be discerned with the following tests:
6391 * - If the maximum distance between any nodes is 1 hop, the system
6392 * is directly connected.
6393 * - If for two nodes A and B, located N > 1 hops away from each other,
6394 * there is an intermediary node C, which is < N hops away from both
6395 * nodes A and B, the system is a glueless mesh.
6397 static void init_numa_topology_type(void)
6401 n = sched_max_numa_distance;
6404 sched_numa_topology_type = NUMA_DIRECT;
6406 for_each_online_node(a) {
6407 for_each_online_node(b) {
6408 /* Find two nodes furthest removed from each other. */
6409 if (node_distance(a, b) < n)
6412 /* Is there an intermediary node between a and b? */
6413 for_each_online_node(c) {
6414 if (node_distance(a, c) < n &&
6415 node_distance(b, c) < n) {
6416 sched_numa_topology_type =
6422 sched_numa_topology_type = NUMA_BACKPLANE;
6428 static void sched_init_numa(void)
6430 int next_distance, curr_distance = node_distance(0, 0);
6431 struct sched_domain_topology_level *tl;
6435 sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL);
6436 if (!sched_domains_numa_distance)
6440 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6441 * unique distances in the node_distance() table.
6443 * Assumes node_distance(0,j) includes all distances in
6444 * node_distance(i,j) in order to avoid cubic time.
6446 next_distance = curr_distance;
6447 for (i = 0; i < nr_node_ids; i++) {
6448 for (j = 0; j < nr_node_ids; j++) {
6449 for (k = 0; k < nr_node_ids; k++) {
6450 int distance = node_distance(i, k);
6452 if (distance > curr_distance &&
6453 (distance < next_distance ||
6454 next_distance == curr_distance))
6455 next_distance = distance;
6458 * While not a strong assumption it would be nice to know
6459 * about cases where if node A is connected to B, B is not
6460 * equally connected to A.
6462 if (sched_debug() && node_distance(k, i) != distance)
6463 sched_numa_warn("Node-distance not symmetric");
6465 if (sched_debug() && i && !find_numa_distance(distance))
6466 sched_numa_warn("Node-0 not representative");
6468 if (next_distance != curr_distance) {
6469 sched_domains_numa_distance[level++] = next_distance;
6470 sched_domains_numa_levels = level;
6471 curr_distance = next_distance;
6476 * In case of sched_debug() we verify the above assumption.
6486 * 'level' contains the number of unique distances, excluding the
6487 * identity distance node_distance(i,i).
6489 * The sched_domains_numa_distance[] array includes the actual distance
6494 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6495 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6496 * the array will contain less then 'level' members. This could be
6497 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6498 * in other functions.
6500 * We reset it to 'level' at the end of this function.
6502 sched_domains_numa_levels = 0;
6504 sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
6505 if (!sched_domains_numa_masks)
6509 * Now for each level, construct a mask per node which contains all
6510 * cpus of nodes that are that many hops away from us.
6512 for (i = 0; i < level; i++) {
6513 sched_domains_numa_masks[i] =
6514 kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL);
6515 if (!sched_domains_numa_masks[i])
6518 for (j = 0; j < nr_node_ids; j++) {
6519 struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
6523 sched_domains_numa_masks[i][j] = mask;
6525 for (k = 0; k < nr_node_ids; k++) {
6526 if (node_distance(j, k) > sched_domains_numa_distance[i])
6529 cpumask_or(mask, mask, cpumask_of_node(k));
6534 /* Compute default topology size */
6535 for (i = 0; sched_domain_topology[i].mask; i++);
6537 tl = kzalloc((i + level + 1) *
6538 sizeof(struct sched_domain_topology_level), GFP_KERNEL);
6543 * Copy the default topology bits..
6545 for (i = 0; sched_domain_topology[i].mask; i++)
6546 tl[i] = sched_domain_topology[i];
6549 * .. and append 'j' levels of NUMA goodness.
6551 for (j = 0; j < level; i++, j++) {
6552 tl[i] = (struct sched_domain_topology_level){
6553 .mask = sd_numa_mask,
6554 .sd_flags = cpu_numa_flags,
6555 .flags = SDTL_OVERLAP,
6561 sched_domain_topology = tl;
6563 sched_domains_numa_levels = level;
6564 sched_max_numa_distance = sched_domains_numa_distance[level - 1];
6566 init_numa_topology_type();
6569 static void sched_domains_numa_masks_set(int cpu)
6572 int node = cpu_to_node(cpu);
6574 for (i = 0; i < sched_domains_numa_levels; i++) {
6575 for (j = 0; j < nr_node_ids; j++) {
6576 if (node_distance(j, node) <= sched_domains_numa_distance[i])
6577 cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
6582 static void sched_domains_numa_masks_clear(int cpu)
6585 for (i = 0; i < sched_domains_numa_levels; i++) {
6586 for (j = 0; j < nr_node_ids; j++)
6587 cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
6592 * Update sched_domains_numa_masks[level][node] array when new cpus
6595 static int sched_domains_numa_masks_update(struct notifier_block *nfb,
6596 unsigned long action,
6599 int cpu = (long)hcpu;
6601 switch (action & ~CPU_TASKS_FROZEN) {
6603 sched_domains_numa_masks_set(cpu);
6607 sched_domains_numa_masks_clear(cpu);
6617 static inline void sched_init_numa(void)
6621 static int sched_domains_numa_masks_update(struct notifier_block *nfb,
6622 unsigned long action,
6627 #endif /* CONFIG_NUMA */
6629 static int __sdt_alloc(const struct cpumask *cpu_map)
6631 struct sched_domain_topology_level *tl;
6634 for_each_sd_topology(tl) {
6635 struct sd_data *sdd = &tl->data;
6637 sdd->sd = alloc_percpu(struct sched_domain *);
6641 sdd->sg = alloc_percpu(struct sched_group *);
6645 sdd->sgc = alloc_percpu(struct sched_group_capacity *);
6649 for_each_cpu(j, cpu_map) {
6650 struct sched_domain *sd;
6651 struct sched_group *sg;
6652 struct sched_group_capacity *sgc;
6654 sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
6655 GFP_KERNEL, cpu_to_node(j));
6659 *per_cpu_ptr(sdd->sd, j) = sd;
6661 sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
6662 GFP_KERNEL, cpu_to_node(j));
6668 *per_cpu_ptr(sdd->sg, j) = sg;
6670 sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(),
6671 GFP_KERNEL, cpu_to_node(j));
6675 *per_cpu_ptr(sdd->sgc, j) = sgc;
6682 static void __sdt_free(const struct cpumask *cpu_map)
6684 struct sched_domain_topology_level *tl;
6687 for_each_sd_topology(tl) {
6688 struct sd_data *sdd = &tl->data;
6690 for_each_cpu(j, cpu_map) {
6691 struct sched_domain *sd;
6694 sd = *per_cpu_ptr(sdd->sd, j);
6695 if (sd && (sd->flags & SD_OVERLAP))
6696 free_sched_groups(sd->groups, 0);
6697 kfree(*per_cpu_ptr(sdd->sd, j));
6701 kfree(*per_cpu_ptr(sdd->sg, j));
6703 kfree(*per_cpu_ptr(sdd->sgc, j));
6705 free_percpu(sdd->sd);
6707 free_percpu(sdd->sg);
6709 free_percpu(sdd->sgc);
6714 struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
6715 const struct cpumask *cpu_map, struct sched_domain_attr *attr,
6716 struct sched_domain *child, int cpu)
6718 struct sched_domain *sd = sd_init(tl, cpu);
6722 cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
6724 sd->level = child->level + 1;
6725 sched_domain_level_max = max(sched_domain_level_max, sd->level);
6729 if (!cpumask_subset(sched_domain_span(child),
6730 sched_domain_span(sd))) {
6731 pr_err("BUG: arch topology borken\n");
6732 #ifdef CONFIG_SCHED_DEBUG
6733 pr_err(" the %s domain not a subset of the %s domain\n",
6734 child->name, sd->name);
6736 /* Fixup, ensure @sd has at least @child cpus. */
6737 cpumask_or(sched_domain_span(sd),
6738 sched_domain_span(sd),
6739 sched_domain_span(child));
6743 set_domain_attribute(sd, attr);
6749 * Build sched domains for a given set of cpus and attach the sched domains
6750 * to the individual cpus
6752 static int build_sched_domains(const struct cpumask *cpu_map,
6753 struct sched_domain_attr *attr)
6755 enum s_alloc alloc_state;
6756 struct sched_domain *sd;
6758 int i, ret = -ENOMEM;
6760 alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
6761 if (alloc_state != sa_rootdomain)
6764 /* Set up domains for cpus specified by the cpu_map. */
6765 for_each_cpu(i, cpu_map) {
6766 struct sched_domain_topology_level *tl;
6769 for_each_sd_topology(tl) {
6770 sd = build_sched_domain(tl, cpu_map, attr, sd, i);
6771 if (tl == sched_domain_topology)
6772 *per_cpu_ptr(d.sd, i) = sd;
6773 if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
6774 sd->flags |= SD_OVERLAP;
6775 if (cpumask_equal(cpu_map, sched_domain_span(sd)))
6780 /* Build the groups for the domains */
6781 for_each_cpu(i, cpu_map) {
6782 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6783 sd->span_weight = cpumask_weight(sched_domain_span(sd));
6784 if (sd->flags & SD_OVERLAP) {
6785 if (build_overlap_sched_groups(sd, i))
6788 if (build_sched_groups(sd, i))
6794 /* Calculate CPU capacity for physical packages and nodes */
6795 for (i = nr_cpumask_bits-1; i >= 0; i--) {
6796 if (!cpumask_test_cpu(i, cpu_map))
6799 for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
6800 claim_allocations(i, sd);
6801 init_sched_groups_capacity(i, sd);
6805 /* Attach the domains */
6807 for_each_cpu(i, cpu_map) {
6808 sd = *per_cpu_ptr(d.sd, i);
6809 cpu_attach_domain(sd, d.rd, i);
6815 __free_domain_allocs(&d, alloc_state, cpu_map);
6819 static cpumask_var_t *doms_cur; /* current sched domains */
6820 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
6821 static struct sched_domain_attr *dattr_cur;
6822 /* attribues of custom domains in 'doms_cur' */
6825 * Special case: If a kmalloc of a doms_cur partition (array of
6826 * cpumask) fails, then fallback to a single sched domain,
6827 * as determined by the single cpumask fallback_doms.
6829 static cpumask_var_t fallback_doms;
6832 * arch_update_cpu_topology lets virtualized architectures update the
6833 * cpu core maps. It is supposed to return 1 if the topology changed
6834 * or 0 if it stayed the same.
6836 int __weak arch_update_cpu_topology(void)
6841 cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
6844 cpumask_var_t *doms;
6846 doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
6849 for (i = 0; i < ndoms; i++) {
6850 if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
6851 free_sched_domains(doms, i);
6858 void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
6861 for (i = 0; i < ndoms; i++)
6862 free_cpumask_var(doms[i]);
6867 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6868 * For now this just excludes isolated cpus, but could be used to
6869 * exclude other special cases in the future.
6871 static int init_sched_domains(const struct cpumask *cpu_map)
6875 arch_update_cpu_topology();
6877 doms_cur = alloc_sched_domains(ndoms_cur);
6879 doms_cur = &fallback_doms;
6880 cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
6881 err = build_sched_domains(doms_cur[0], NULL);
6882 register_sched_domain_sysctl();
6888 * Detach sched domains from a group of cpus specified in cpu_map
6889 * These cpus will now be attached to the NULL domain
6891 static void detach_destroy_domains(const struct cpumask *cpu_map)
6896 for_each_cpu(i, cpu_map)
6897 cpu_attach_domain(NULL, &def_root_domain, i);
6901 /* handle null as "default" */
6902 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
6903 struct sched_domain_attr *new, int idx_new)
6905 struct sched_domain_attr tmp;
6912 return !memcmp(cur ? (cur + idx_cur) : &tmp,
6913 new ? (new + idx_new) : &tmp,
6914 sizeof(struct sched_domain_attr));
6918 * Partition sched domains as specified by the 'ndoms_new'
6919 * cpumasks in the array doms_new[] of cpumasks. This compares
6920 * doms_new[] to the current sched domain partitioning, doms_cur[].
6921 * It destroys each deleted domain and builds each new domain.
6923 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6924 * The masks don't intersect (don't overlap.) We should setup one
6925 * sched domain for each mask. CPUs not in any of the cpumasks will
6926 * not be load balanced. If the same cpumask appears both in the
6927 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6930 * The passed in 'doms_new' should be allocated using
6931 * alloc_sched_domains. This routine takes ownership of it and will
6932 * free_sched_domains it when done with it. If the caller failed the
6933 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6934 * and partition_sched_domains() will fallback to the single partition
6935 * 'fallback_doms', it also forces the domains to be rebuilt.
6937 * If doms_new == NULL it will be replaced with cpu_online_mask.
6938 * ndoms_new == 0 is a special case for destroying existing domains,
6939 * and it will not create the default domain.
6941 * Call with hotplug lock held
6943 void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
6944 struct sched_domain_attr *dattr_new)
6949 mutex_lock(&sched_domains_mutex);
6951 /* always unregister in case we don't destroy any domains */
6952 unregister_sched_domain_sysctl();
6954 /* Let architecture update cpu core mappings. */
6955 new_topology = arch_update_cpu_topology();
6957 n = doms_new ? ndoms_new : 0;
6959 /* Destroy deleted domains */
6960 for (i = 0; i < ndoms_cur; i++) {
6961 for (j = 0; j < n && !new_topology; j++) {
6962 if (cpumask_equal(doms_cur[i], doms_new[j])
6963 && dattrs_equal(dattr_cur, i, dattr_new, j))
6966 /* no match - a current sched domain not in new doms_new[] */
6967 detach_destroy_domains(doms_cur[i]);
6973 if (doms_new == NULL) {
6975 doms_new = &fallback_doms;
6976 cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
6977 WARN_ON_ONCE(dattr_new);
6980 /* Build new domains */
6981 for (i = 0; i < ndoms_new; i++) {
6982 for (j = 0; j < n && !new_topology; j++) {
6983 if (cpumask_equal(doms_new[i], doms_cur[j])
6984 && dattrs_equal(dattr_new, i, dattr_cur, j))
6987 /* no match - add a new doms_new */
6988 build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
6993 /* Remember the new sched domains */
6994 if (doms_cur != &fallback_doms)
6995 free_sched_domains(doms_cur, ndoms_cur);
6996 kfree(dattr_cur); /* kfree(NULL) is safe */
6997 doms_cur = doms_new;
6998 dattr_cur = dattr_new;
6999 ndoms_cur = ndoms_new;
7001 register_sched_domain_sysctl();
7003 mutex_unlock(&sched_domains_mutex);
7006 static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */
7009 * Update cpusets according to cpu_active mask. If cpusets are
7010 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7011 * around partition_sched_domains().
7013 * If we come here as part of a suspend/resume, don't touch cpusets because we
7014 * want to restore it back to its original state upon resume anyway.
7016 static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
7020 case CPU_ONLINE_FROZEN:
7021 case CPU_DOWN_FAILED_FROZEN:
7024 * num_cpus_frozen tracks how many CPUs are involved in suspend
7025 * resume sequence. As long as this is not the last online
7026 * operation in the resume sequence, just build a single sched
7027 * domain, ignoring cpusets.
7030 if (likely(num_cpus_frozen)) {
7031 partition_sched_domains(1, NULL, NULL);
7036 * This is the last CPU online operation. So fall through and
7037 * restore the original sched domains by considering the
7038 * cpuset configurations.
7042 case CPU_DOWN_FAILED:
7043 cpuset_update_active_cpus(true);
7051 static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
7055 case CPU_DOWN_PREPARE:
7056 cpuset_update_active_cpus(false);
7058 case CPU_DOWN_PREPARE_FROZEN:
7060 partition_sched_domains(1, NULL, NULL);
7068 void __init sched_init_smp(void)
7070 cpumask_var_t non_isolated_cpus;
7072 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
7073 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
7078 * There's no userspace yet to cause hotplug operations; hence all the
7079 * cpu masks are stable and all blatant races in the below code cannot
7082 mutex_lock(&sched_domains_mutex);
7083 init_sched_domains(cpu_active_mask);
7084 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
7085 if (cpumask_empty(non_isolated_cpus))
7086 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
7087 mutex_unlock(&sched_domains_mutex);
7089 hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
7090 hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
7091 hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
7095 /* Move init over to a non-isolated CPU */
7096 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
7098 sched_init_granularity();
7099 free_cpumask_var(non_isolated_cpus);
7101 init_sched_rt_class();
7102 init_sched_dl_class();
7105 void __init sched_init_smp(void)
7107 sched_init_granularity();
7109 #endif /* CONFIG_SMP */
7111 const_debug unsigned int sysctl_timer_migration = 1;
7113 int in_sched_functions(unsigned long addr)
7115 return in_lock_functions(addr) ||
7116 (addr >= (unsigned long)__sched_text_start
7117 && addr < (unsigned long)__sched_text_end);
7120 #ifdef CONFIG_CGROUP_SCHED
7122 * Default task group.
7123 * Every task in system belongs to this group at bootup.
7125 struct task_group root_task_group;
7126 LIST_HEAD(task_groups);
7129 DECLARE_PER_CPU(cpumask_var_t, load_balance_mask);
7131 void __init sched_init(void)
7134 unsigned long alloc_size = 0, ptr;
7136 #ifdef CONFIG_FAIR_GROUP_SCHED
7137 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7139 #ifdef CONFIG_RT_GROUP_SCHED
7140 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7143 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
7145 #ifdef CONFIG_FAIR_GROUP_SCHED
7146 root_task_group.se = (struct sched_entity **)ptr;
7147 ptr += nr_cpu_ids * sizeof(void **);
7149 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
7150 ptr += nr_cpu_ids * sizeof(void **);
7152 #endif /* CONFIG_FAIR_GROUP_SCHED */
7153 #ifdef CONFIG_RT_GROUP_SCHED
7154 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
7155 ptr += nr_cpu_ids * sizeof(void **);
7157 root_task_group.rt_rq = (struct rt_rq **)ptr;
7158 ptr += nr_cpu_ids * sizeof(void **);
7160 #endif /* CONFIG_RT_GROUP_SCHED */
7162 #ifdef CONFIG_CPUMASK_OFFSTACK
7163 for_each_possible_cpu(i) {
7164 per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node(
7165 cpumask_size(), GFP_KERNEL, cpu_to_node(i));
7167 #endif /* CONFIG_CPUMASK_OFFSTACK */
7169 init_rt_bandwidth(&def_rt_bandwidth,
7170 global_rt_period(), global_rt_runtime());
7171 init_dl_bandwidth(&def_dl_bandwidth,
7172 global_rt_period(), global_rt_runtime());
7175 init_defrootdomain();
7178 #ifdef CONFIG_RT_GROUP_SCHED
7179 init_rt_bandwidth(&root_task_group.rt_bandwidth,
7180 global_rt_period(), global_rt_runtime());
7181 #endif /* CONFIG_RT_GROUP_SCHED */
7183 #ifdef CONFIG_CGROUP_SCHED
7184 list_add(&root_task_group.list, &task_groups);
7185 INIT_LIST_HEAD(&root_task_group.children);
7186 INIT_LIST_HEAD(&root_task_group.siblings);
7187 autogroup_init(&init_task);
7189 #endif /* CONFIG_CGROUP_SCHED */
7191 for_each_possible_cpu(i) {
7195 raw_spin_lock_init(&rq->lock);
7197 rq->calc_load_active = 0;
7198 rq->calc_load_update = jiffies + LOAD_FREQ;
7199 init_cfs_rq(&rq->cfs);
7200 init_rt_rq(&rq->rt, rq);
7201 init_dl_rq(&rq->dl, rq);
7202 #ifdef CONFIG_FAIR_GROUP_SCHED
7203 root_task_group.shares = ROOT_TASK_GROUP_LOAD;
7204 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
7206 * How much cpu bandwidth does root_task_group get?
7208 * In case of task-groups formed thr' the cgroup filesystem, it
7209 * gets 100% of the cpu resources in the system. This overall
7210 * system cpu resource is divided among the tasks of
7211 * root_task_group and its child task-groups in a fair manner,
7212 * based on each entity's (task or task-group's) weight
7213 * (se->load.weight).
7215 * In other words, if root_task_group has 10 tasks of weight
7216 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7217 * then A0's share of the cpu resource is:
7219 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7221 * We achieve this by letting root_task_group's tasks sit
7222 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7224 init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
7225 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
7226 #endif /* CONFIG_FAIR_GROUP_SCHED */
7228 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
7229 #ifdef CONFIG_RT_GROUP_SCHED
7230 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
7233 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
7234 rq->cpu_load[j] = 0;
7236 rq->last_load_update_tick = jiffies;
7241 rq->cpu_capacity = SCHED_CAPACITY_SCALE;
7242 rq->post_schedule = 0;
7243 rq->active_balance = 0;
7244 rq->next_balance = jiffies;
7249 rq->avg_idle = 2*sysctl_sched_migration_cost;
7250 rq->max_idle_balance_cost = sysctl_sched_migration_cost;
7252 INIT_LIST_HEAD(&rq->cfs_tasks);
7254 rq_attach_root(rq, &def_root_domain);
7255 #ifdef CONFIG_NO_HZ_COMMON
7258 #ifdef CONFIG_NO_HZ_FULL
7259 rq->last_sched_tick = 0;
7263 atomic_set(&rq->nr_iowait, 0);
7266 set_load_weight(&init_task);
7268 #ifdef CONFIG_PREEMPT_NOTIFIERS
7269 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
7273 * The boot idle thread does lazy MMU switching as well:
7275 atomic_inc(&init_mm.mm_count);
7276 enter_lazy_tlb(&init_mm, current);
7279 * Make us the idle thread. Technically, schedule() should not be
7280 * called from this thread, however somewhere below it might be,
7281 * but because we are the idle thread, we just pick up running again
7282 * when this runqueue becomes "idle".
7284 init_idle(current, smp_processor_id());
7286 calc_load_update = jiffies + LOAD_FREQ;
7289 * During early bootup we pretend to be a normal task:
7291 current->sched_class = &fair_sched_class;
7294 zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
7295 /* May be allocated at isolcpus cmdline parse time */
7296 if (cpu_isolated_map == NULL)
7297 zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
7298 idle_thread_set_boot_cpu();
7299 set_cpu_rq_start_time();
7301 init_sched_fair_class();
7303 scheduler_running = 1;
7306 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7307 static inline int preempt_count_equals(int preempt_offset)
7309 int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
7311 return (nested == preempt_offset);
7314 void __might_sleep(const char *file, int line, int preempt_offset)
7317 * Blocking primitives will set (and therefore destroy) current->state,
7318 * since we will exit with TASK_RUNNING make sure we enter with it,
7319 * otherwise we will destroy state.
7321 WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
7322 "do not call blocking ops when !TASK_RUNNING; "
7323 "state=%lx set at [<%p>] %pS\n",
7325 (void *)current->task_state_change,
7326 (void *)current->task_state_change);
7328 ___might_sleep(file, line, preempt_offset);
7330 EXPORT_SYMBOL(__might_sleep);
7332 void ___might_sleep(const char *file, int line, int preempt_offset)
7334 static unsigned long prev_jiffy; /* ratelimiting */
7336 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7337 if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
7338 !is_idle_task(current)) ||
7339 system_state != SYSTEM_RUNNING || oops_in_progress)
7341 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
7343 prev_jiffy = jiffies;
7346 "BUG: sleeping function called from invalid context at %s:%d\n",
7349 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7350 in_atomic(), irqs_disabled(),
7351 current->pid, current->comm);
7353 debug_show_held_locks(current);
7354 if (irqs_disabled())
7355 print_irqtrace_events(current);
7356 #ifdef CONFIG_DEBUG_PREEMPT
7357 if (!preempt_count_equals(preempt_offset)) {
7358 pr_err("Preemption disabled at:");
7359 print_ip_sym(current->preempt_disable_ip);
7365 EXPORT_SYMBOL(___might_sleep);
7368 #ifdef CONFIG_MAGIC_SYSRQ
7369 static void normalize_task(struct rq *rq, struct task_struct *p)
7371 const struct sched_class *prev_class = p->sched_class;
7372 struct sched_attr attr = {
7373 .sched_policy = SCHED_NORMAL,
7375 int old_prio = p->prio;
7378 queued = task_on_rq_queued(p);
7380 dequeue_task(rq, p, 0);
7381 __setscheduler(rq, p, &attr);
7383 enqueue_task(rq, p, 0);
7387 check_class_changed(rq, p, prev_class, old_prio);
7390 void normalize_rt_tasks(void)
7392 struct task_struct *g, *p;
7393 unsigned long flags;
7396 read_lock(&tasklist_lock);
7397 for_each_process_thread(g, p) {
7399 * Only normalize user tasks:
7401 if (p->flags & PF_KTHREAD)
7404 p->se.exec_start = 0;
7405 #ifdef CONFIG_SCHEDSTATS
7406 p->se.statistics.wait_start = 0;
7407 p->se.statistics.sleep_start = 0;
7408 p->se.statistics.block_start = 0;
7411 if (!dl_task(p) && !rt_task(p)) {
7413 * Renice negative nice level userspace
7416 if (task_nice(p) < 0)
7417 set_user_nice(p, 0);
7421 rq = task_rq_lock(p, &flags);
7422 normalize_task(rq, p);
7423 task_rq_unlock(rq, p, &flags);
7425 read_unlock(&tasklist_lock);
7428 #endif /* CONFIG_MAGIC_SYSRQ */
7430 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7432 * These functions are only useful for the IA64 MCA handling, or kdb.
7434 * They can only be called when the whole system has been
7435 * stopped - every CPU needs to be quiescent, and no scheduling
7436 * activity can take place. Using them for anything else would
7437 * be a serious bug, and as a result, they aren't even visible
7438 * under any other configuration.
7442 * curr_task - return the current task for a given cpu.
7443 * @cpu: the processor in question.
7445 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7447 * Return: The current task for @cpu.
7449 struct task_struct *curr_task(int cpu)
7451 return cpu_curr(cpu);
7454 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7458 * set_curr_task - set the current task for a given cpu.
7459 * @cpu: the processor in question.
7460 * @p: the task pointer to set.
7462 * Description: This function must only be used when non-maskable interrupts
7463 * are serviced on a separate stack. It allows the architecture to switch the
7464 * notion of the current task on a cpu in a non-blocking manner. This function
7465 * must be called with all CPU's synchronized, and interrupts disabled, the
7466 * and caller must save the original value of the current task (see
7467 * curr_task() above) and restore that value before reenabling interrupts and
7468 * re-starting the system.
7470 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7472 void set_curr_task(int cpu, struct task_struct *p)
7479 #ifdef CONFIG_CGROUP_SCHED
7480 /* task_group_lock serializes the addition/removal of task groups */
7481 static DEFINE_SPINLOCK(task_group_lock);
7483 static void free_sched_group(struct task_group *tg)
7485 free_fair_sched_group(tg);
7486 free_rt_sched_group(tg);
7491 /* allocate runqueue etc for a new task group */
7492 struct task_group *sched_create_group(struct task_group *parent)
7494 struct task_group *tg;
7496 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
7498 return ERR_PTR(-ENOMEM);
7500 if (!alloc_fair_sched_group(tg, parent))
7503 if (!alloc_rt_sched_group(tg, parent))
7509 free_sched_group(tg);
7510 return ERR_PTR(-ENOMEM);
7513 void sched_online_group(struct task_group *tg, struct task_group *parent)
7515 unsigned long flags;
7517 spin_lock_irqsave(&task_group_lock, flags);
7518 list_add_rcu(&tg->list, &task_groups);
7520 WARN_ON(!parent); /* root should already exist */
7522 tg->parent = parent;
7523 INIT_LIST_HEAD(&tg->children);
7524 list_add_rcu(&tg->siblings, &parent->children);
7525 spin_unlock_irqrestore(&task_group_lock, flags);
7528 /* rcu callback to free various structures associated with a task group */
7529 static void free_sched_group_rcu(struct rcu_head *rhp)
7531 /* now it should be safe to free those cfs_rqs */
7532 free_sched_group(container_of(rhp, struct task_group, rcu));
7535 /* Destroy runqueue etc associated with a task group */
7536 void sched_destroy_group(struct task_group *tg)
7538 /* wait for possible concurrent references to cfs_rqs complete */
7539 call_rcu(&tg->rcu, free_sched_group_rcu);
7542 void sched_offline_group(struct task_group *tg)
7544 unsigned long flags;
7547 /* end participation in shares distribution */
7548 for_each_possible_cpu(i)
7549 unregister_fair_sched_group(tg, i);
7551 spin_lock_irqsave(&task_group_lock, flags);
7552 list_del_rcu(&tg->list);
7553 list_del_rcu(&tg->siblings);
7554 spin_unlock_irqrestore(&task_group_lock, flags);
7557 /* change task's runqueue when it moves between groups.
7558 * The caller of this function should have put the task in its new group
7559 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7560 * reflect its new group.
7562 void sched_move_task(struct task_struct *tsk)
7564 struct task_group *tg;
7565 int queued, running;
7566 unsigned long flags;
7569 rq = task_rq_lock(tsk, &flags);
7571 running = task_current(rq, tsk);
7572 queued = task_on_rq_queued(tsk);
7575 dequeue_task(rq, tsk, 0);
7576 if (unlikely(running))
7577 put_prev_task(rq, tsk);
7580 * All callers are synchronized by task_rq_lock(); we do not use RCU
7581 * which is pointless here. Thus, we pass "true" to task_css_check()
7582 * to prevent lockdep warnings.
7584 tg = container_of(task_css_check(tsk, cpu_cgrp_id, true),
7585 struct task_group, css);
7586 tg = autogroup_task_group(tsk, tg);
7587 tsk->sched_task_group = tg;
7589 #ifdef CONFIG_FAIR_GROUP_SCHED
7590 if (tsk->sched_class->task_move_group)
7591 tsk->sched_class->task_move_group(tsk, queued);
7594 set_task_rq(tsk, task_cpu(tsk));
7596 if (unlikely(running))
7597 tsk->sched_class->set_curr_task(rq);
7599 enqueue_task(rq, tsk, 0);
7601 task_rq_unlock(rq, tsk, &flags);
7603 #endif /* CONFIG_CGROUP_SCHED */
7605 #ifdef CONFIG_RT_GROUP_SCHED
7607 * Ensure that the real time constraints are schedulable.
7609 static DEFINE_MUTEX(rt_constraints_mutex);
7611 /* Must be called with tasklist_lock held */
7612 static inline int tg_has_rt_tasks(struct task_group *tg)
7614 struct task_struct *g, *p;
7616 for_each_process_thread(g, p) {
7617 if (rt_task(p) && task_group(p) == tg)
7624 struct rt_schedulable_data {
7625 struct task_group *tg;
7630 static int tg_rt_schedulable(struct task_group *tg, void *data)
7632 struct rt_schedulable_data *d = data;
7633 struct task_group *child;
7634 unsigned long total, sum = 0;
7635 u64 period, runtime;
7637 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7638 runtime = tg->rt_bandwidth.rt_runtime;
7641 period = d->rt_period;
7642 runtime = d->rt_runtime;
7646 * Cannot have more runtime than the period.
7648 if (runtime > period && runtime != RUNTIME_INF)
7652 * Ensure we don't starve existing RT tasks.
7654 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
7657 total = to_ratio(period, runtime);
7660 * Nobody can have more than the global setting allows.
7662 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
7666 * The sum of our children's runtime should not exceed our own.
7668 list_for_each_entry_rcu(child, &tg->children, siblings) {
7669 period = ktime_to_ns(child->rt_bandwidth.rt_period);
7670 runtime = child->rt_bandwidth.rt_runtime;
7672 if (child == d->tg) {
7673 period = d->rt_period;
7674 runtime = d->rt_runtime;
7677 sum += to_ratio(period, runtime);
7686 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
7690 struct rt_schedulable_data data = {
7692 .rt_period = period,
7693 .rt_runtime = runtime,
7697 ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
7703 static int tg_set_rt_bandwidth(struct task_group *tg,
7704 u64 rt_period, u64 rt_runtime)
7708 mutex_lock(&rt_constraints_mutex);
7709 read_lock(&tasklist_lock);
7710 err = __rt_schedulable(tg, rt_period, rt_runtime);
7714 raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7715 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
7716 tg->rt_bandwidth.rt_runtime = rt_runtime;
7718 for_each_possible_cpu(i) {
7719 struct rt_rq *rt_rq = tg->rt_rq[i];
7721 raw_spin_lock(&rt_rq->rt_runtime_lock);
7722 rt_rq->rt_runtime = rt_runtime;
7723 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7725 raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
7727 read_unlock(&tasklist_lock);
7728 mutex_unlock(&rt_constraints_mutex);
7733 static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
7735 u64 rt_runtime, rt_period;
7737 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
7738 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
7739 if (rt_runtime_us < 0)
7740 rt_runtime = RUNTIME_INF;
7742 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7745 static long sched_group_rt_runtime(struct task_group *tg)
7749 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
7752 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
7753 do_div(rt_runtime_us, NSEC_PER_USEC);
7754 return rt_runtime_us;
7757 static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
7759 u64 rt_runtime, rt_period;
7761 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
7762 rt_runtime = tg->rt_bandwidth.rt_runtime;
7767 return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
7770 static long sched_group_rt_period(struct task_group *tg)
7774 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
7775 do_div(rt_period_us, NSEC_PER_USEC);
7776 return rt_period_us;
7778 #endif /* CONFIG_RT_GROUP_SCHED */
7780 #ifdef CONFIG_RT_GROUP_SCHED
7781 static int sched_rt_global_constraints(void)
7785 mutex_lock(&rt_constraints_mutex);
7786 read_lock(&tasklist_lock);
7787 ret = __rt_schedulable(NULL, 0, 0);
7788 read_unlock(&tasklist_lock);
7789 mutex_unlock(&rt_constraints_mutex);
7794 static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
7796 /* Don't accept realtime tasks when there is no way for them to run */
7797 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
7803 #else /* !CONFIG_RT_GROUP_SCHED */
7804 static int sched_rt_global_constraints(void)
7806 unsigned long flags;
7809 raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
7810 for_each_possible_cpu(i) {
7811 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
7813 raw_spin_lock(&rt_rq->rt_runtime_lock);
7814 rt_rq->rt_runtime = global_rt_runtime();
7815 raw_spin_unlock(&rt_rq->rt_runtime_lock);
7817 raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
7821 #endif /* CONFIG_RT_GROUP_SCHED */
7823 static int sched_dl_global_constraints(void)
7825 u64 runtime = global_rt_runtime();
7826 u64 period = global_rt_period();
7827 u64 new_bw = to_ratio(period, runtime);
7830 unsigned long flags;
7833 * Here we want to check the bandwidth not being set to some
7834 * value smaller than the currently allocated bandwidth in
7835 * any of the root_domains.
7837 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7838 * cycling on root_domains... Discussion on different/better
7839 * solutions is welcome!
7841 for_each_possible_cpu(cpu) {
7842 rcu_read_lock_sched();
7843 dl_b = dl_bw_of(cpu);
7845 raw_spin_lock_irqsave(&dl_b->lock, flags);
7846 if (new_bw < dl_b->total_bw)
7848 raw_spin_unlock_irqrestore(&dl_b->lock, flags);
7850 rcu_read_unlock_sched();
7859 static void sched_dl_do_global(void)
7864 unsigned long flags;
7866 def_dl_bandwidth.dl_period = global_rt_period();
7867 def_dl_bandwidth.dl_runtime = global_rt_runtime();
7869 if (global_rt_runtime() != RUNTIME_INF)
7870 new_bw = to_ratio(global_rt_period(), global_rt_runtime());
7873 * FIXME: As above...
7875 for_each_possible_cpu(cpu) {
7876 rcu_read_lock_sched();
7877 dl_b = dl_bw_of(cpu);
7879 raw_spin_lock_irqsave(&dl_b->lock, flags);
7881 raw_spin_unlock_irqrestore(&dl_b->lock, flags);
7883 rcu_read_unlock_sched();
7887 static int sched_rt_global_validate(void)
7889 if (sysctl_sched_rt_period <= 0)
7892 if ((sysctl_sched_rt_runtime != RUNTIME_INF) &&
7893 (sysctl_sched_rt_runtime > sysctl_sched_rt_period))
7899 static void sched_rt_do_global(void)
7901 def_rt_bandwidth.rt_runtime = global_rt_runtime();
7902 def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period());
7905 int sched_rt_handler(struct ctl_table *table, int write,
7906 void __user *buffer, size_t *lenp,
7909 int old_period, old_runtime;
7910 static DEFINE_MUTEX(mutex);
7914 old_period = sysctl_sched_rt_period;
7915 old_runtime = sysctl_sched_rt_runtime;
7917 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7919 if (!ret && write) {
7920 ret = sched_rt_global_validate();
7924 ret = sched_rt_global_constraints();
7928 ret = sched_dl_global_constraints();
7932 sched_rt_do_global();
7933 sched_dl_do_global();
7937 sysctl_sched_rt_period = old_period;
7938 sysctl_sched_rt_runtime = old_runtime;
7940 mutex_unlock(&mutex);
7945 int sched_rr_handler(struct ctl_table *table, int write,
7946 void __user *buffer, size_t *lenp,
7950 static DEFINE_MUTEX(mutex);
7953 ret = proc_dointvec(table, write, buffer, lenp, ppos);
7954 /* make sure that internally we keep jiffies */
7955 /* also, writing zero resets timeslice to default */
7956 if (!ret && write) {
7957 sched_rr_timeslice = sched_rr_timeslice <= 0 ?
7958 RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice);
7960 mutex_unlock(&mutex);
7964 #ifdef CONFIG_CGROUP_SCHED
7966 static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
7968 return css ? container_of(css, struct task_group, css) : NULL;
7971 static struct cgroup_subsys_state *
7972 cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
7974 struct task_group *parent = css_tg(parent_css);
7975 struct task_group *tg;
7978 /* This is early initialization for the top cgroup */
7979 return &root_task_group.css;
7982 tg = sched_create_group(parent);
7984 return ERR_PTR(-ENOMEM);
7989 static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
7991 struct task_group *tg = css_tg(css);
7992 struct task_group *parent = css_tg(css->parent);
7995 sched_online_group(tg, parent);
7999 static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
8001 struct task_group *tg = css_tg(css);
8003 sched_destroy_group(tg);
8006 static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css)
8008 struct task_group *tg = css_tg(css);
8010 sched_offline_group(tg);
8013 static void cpu_cgroup_fork(struct task_struct *task)
8015 sched_move_task(task);
8018 static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css,
8019 struct cgroup_taskset *tset)
8021 struct task_struct *task;
8023 cgroup_taskset_for_each(task, tset) {
8024 #ifdef CONFIG_RT_GROUP_SCHED
8025 if (!sched_rt_can_attach(css_tg(css), task))
8028 /* We don't support RT-tasks being in separate groups */
8029 if (task->sched_class != &fair_sched_class)
8036 static void cpu_cgroup_attach(struct cgroup_subsys_state *css,
8037 struct cgroup_taskset *tset)
8039 struct task_struct *task;
8041 cgroup_taskset_for_each(task, tset)
8042 sched_move_task(task);
8045 static void cpu_cgroup_exit(struct cgroup_subsys_state *css,
8046 struct cgroup_subsys_state *old_css,
8047 struct task_struct *task)
8050 * cgroup_exit() is called in the copy_process() failure path.
8051 * Ignore this case since the task hasn't ran yet, this avoids
8052 * trying to poke a half freed task state from generic code.
8054 if (!(task->flags & PF_EXITING))
8057 sched_move_task(task);
8060 #ifdef CONFIG_FAIR_GROUP_SCHED
8061 static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
8062 struct cftype *cftype, u64 shareval)
8064 return sched_group_set_shares(css_tg(css), scale_load(shareval));
8067 static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
8070 struct task_group *tg = css_tg(css);
8072 return (u64) scale_load_down(tg->shares);
8075 #ifdef CONFIG_CFS_BANDWIDTH
8076 static DEFINE_MUTEX(cfs_constraints_mutex);
8078 const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */
8079 const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */
8081 static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime);
8083 static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
8085 int i, ret = 0, runtime_enabled, runtime_was_enabled;
8086 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8088 if (tg == &root_task_group)
8092 * Ensure we have at some amount of bandwidth every period. This is
8093 * to prevent reaching a state of large arrears when throttled via
8094 * entity_tick() resulting in prolonged exit starvation.
8096 if (quota < min_cfs_quota_period || period < min_cfs_quota_period)
8100 * Likewise, bound things on the otherside by preventing insane quota
8101 * periods. This also allows us to normalize in computing quota
8104 if (period > max_cfs_quota_period)
8108 * Prevent race between setting of cfs_rq->runtime_enabled and
8109 * unthrottle_offline_cfs_rqs().
8112 mutex_lock(&cfs_constraints_mutex);
8113 ret = __cfs_schedulable(tg, period, quota);
8117 runtime_enabled = quota != RUNTIME_INF;
8118 runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
8120 * If we need to toggle cfs_bandwidth_used, off->on must occur
8121 * before making related changes, and on->off must occur afterwards
8123 if (runtime_enabled && !runtime_was_enabled)
8124 cfs_bandwidth_usage_inc();
8125 raw_spin_lock_irq(&cfs_b->lock);
8126 cfs_b->period = ns_to_ktime(period);
8127 cfs_b->quota = quota;
8129 __refill_cfs_bandwidth_runtime(cfs_b);
8130 /* restart the period timer (if active) to handle new period expiry */
8131 if (runtime_enabled && cfs_b->timer_active) {
8132 /* force a reprogram */
8133 __start_cfs_bandwidth(cfs_b, true);
8135 raw_spin_unlock_irq(&cfs_b->lock);
8137 for_each_online_cpu(i) {
8138 struct cfs_rq *cfs_rq = tg->cfs_rq[i];
8139 struct rq *rq = cfs_rq->rq;
8141 raw_spin_lock_irq(&rq->lock);
8142 cfs_rq->runtime_enabled = runtime_enabled;
8143 cfs_rq->runtime_remaining = 0;
8145 if (cfs_rq->throttled)
8146 unthrottle_cfs_rq(cfs_rq);
8147 raw_spin_unlock_irq(&rq->lock);
8149 if (runtime_was_enabled && !runtime_enabled)
8150 cfs_bandwidth_usage_dec();
8152 mutex_unlock(&cfs_constraints_mutex);
8158 int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)
8162 period = ktime_to_ns(tg->cfs_bandwidth.period);
8163 if (cfs_quota_us < 0)
8164 quota = RUNTIME_INF;
8166 quota = (u64)cfs_quota_us * NSEC_PER_USEC;
8168 return tg_set_cfs_bandwidth(tg, period, quota);
8171 long tg_get_cfs_quota(struct task_group *tg)
8175 if (tg->cfs_bandwidth.quota == RUNTIME_INF)
8178 quota_us = tg->cfs_bandwidth.quota;
8179 do_div(quota_us, NSEC_PER_USEC);
8184 int tg_set_cfs_period(struct task_group *tg, long cfs_period_us)
8188 period = (u64)cfs_period_us * NSEC_PER_USEC;
8189 quota = tg->cfs_bandwidth.quota;
8191 return tg_set_cfs_bandwidth(tg, period, quota);
8194 long tg_get_cfs_period(struct task_group *tg)
8198 cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period);
8199 do_div(cfs_period_us, NSEC_PER_USEC);
8201 return cfs_period_us;
8204 static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css,
8207 return tg_get_cfs_quota(css_tg(css));
8210 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css,
8211 struct cftype *cftype, s64 cfs_quota_us)
8213 return tg_set_cfs_quota(css_tg(css), cfs_quota_us);
8216 static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css,
8219 return tg_get_cfs_period(css_tg(css));
8222 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css,
8223 struct cftype *cftype, u64 cfs_period_us)
8225 return tg_set_cfs_period(css_tg(css), cfs_period_us);
8228 struct cfs_schedulable_data {
8229 struct task_group *tg;
8234 * normalize group quota/period to be quota/max_period
8235 * note: units are usecs
8237 static u64 normalize_cfs_quota(struct task_group *tg,
8238 struct cfs_schedulable_data *d)
8246 period = tg_get_cfs_period(tg);
8247 quota = tg_get_cfs_quota(tg);
8250 /* note: these should typically be equivalent */
8251 if (quota == RUNTIME_INF || quota == -1)
8254 return to_ratio(period, quota);
8257 static int tg_cfs_schedulable_down(struct task_group *tg, void *data)
8259 struct cfs_schedulable_data *d = data;
8260 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8261 s64 quota = 0, parent_quota = -1;
8264 quota = RUNTIME_INF;
8266 struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth;
8268 quota = normalize_cfs_quota(tg, d);
8269 parent_quota = parent_b->hierarchical_quota;
8272 * ensure max(child_quota) <= parent_quota, inherit when no
8275 if (quota == RUNTIME_INF)
8276 quota = parent_quota;
8277 else if (parent_quota != RUNTIME_INF && quota > parent_quota)
8280 cfs_b->hierarchical_quota = quota;
8285 static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
8288 struct cfs_schedulable_data data = {
8294 if (quota != RUNTIME_INF) {
8295 do_div(data.period, NSEC_PER_USEC);
8296 do_div(data.quota, NSEC_PER_USEC);
8300 ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);
8306 static int cpu_stats_show(struct seq_file *sf, void *v)
8308 struct task_group *tg = css_tg(seq_css(sf));
8309 struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
8311 seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods);
8312 seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled);
8313 seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time);
8317 #endif /* CONFIG_CFS_BANDWIDTH */
8318 #endif /* CONFIG_FAIR_GROUP_SCHED */
8320 #ifdef CONFIG_RT_GROUP_SCHED
8321 static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
8322 struct cftype *cft, s64 val)
8324 return sched_group_set_rt_runtime(css_tg(css), val);
8327 static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css,
8330 return sched_group_rt_runtime(css_tg(css));
8333 static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css,
8334 struct cftype *cftype, u64 rt_period_us)
8336 return sched_group_set_rt_period(css_tg(css), rt_period_us);
8339 static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
8342 return sched_group_rt_period(css_tg(css));
8344 #endif /* CONFIG_RT_GROUP_SCHED */
8346 static struct cftype cpu_files[] = {
8347 #ifdef CONFIG_FAIR_GROUP_SCHED
8350 .read_u64 = cpu_shares_read_u64,
8351 .write_u64 = cpu_shares_write_u64,
8354 #ifdef CONFIG_CFS_BANDWIDTH
8356 .name = "cfs_quota_us",
8357 .read_s64 = cpu_cfs_quota_read_s64,
8358 .write_s64 = cpu_cfs_quota_write_s64,
8361 .name = "cfs_period_us",
8362 .read_u64 = cpu_cfs_period_read_u64,
8363 .write_u64 = cpu_cfs_period_write_u64,
8367 .seq_show = cpu_stats_show,
8370 #ifdef CONFIG_RT_GROUP_SCHED
8372 .name = "rt_runtime_us",
8373 .read_s64 = cpu_rt_runtime_read,
8374 .write_s64 = cpu_rt_runtime_write,
8377 .name = "rt_period_us",
8378 .read_u64 = cpu_rt_period_read_uint,
8379 .write_u64 = cpu_rt_period_write_uint,
8385 struct cgroup_subsys cpu_cgrp_subsys = {
8386 .css_alloc = cpu_cgroup_css_alloc,
8387 .css_free = cpu_cgroup_css_free,
8388 .css_online = cpu_cgroup_css_online,
8389 .css_offline = cpu_cgroup_css_offline,
8390 .fork = cpu_cgroup_fork,
8391 .can_attach = cpu_cgroup_can_attach,
8392 .attach = cpu_cgroup_attach,
8393 .exit = cpu_cgroup_exit,
8394 .legacy_cftypes = cpu_files,
8398 #endif /* CONFIG_CGROUP_SCHED */
8400 void dump_cpu_task(int cpu)
8402 pr_info("Task dump for CPU %d:\n", cpu);
8403 sched_show_task(cpu_curr(cpu));