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>
77 #include <asm/switch_to.h>
79 #include <asm/irq_regs.h>
80 #include <asm/mutex.h>
81 #ifdef CONFIG_PARAVIRT
82 #include <asm/paravirt.h>
86 #include "../workqueue_internal.h"
87 #include "../smpboot.h"
89 #define CREATE_TRACE_POINTS
90 #include <trace/events/sched.h>
92 void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
95 ktime_t soft
, hard
, now
;
98 if (hrtimer_active(period_timer
))
101 now
= hrtimer_cb_get_time(period_timer
);
102 hrtimer_forward(period_timer
, now
, period
);
104 soft
= hrtimer_get_softexpires(period_timer
);
105 hard
= hrtimer_get_expires(period_timer
);
106 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
107 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
108 HRTIMER_MODE_ABS_PINNED
, 0);
112 DEFINE_MUTEX(sched_domains_mutex
);
113 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
115 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
117 void update_rq_clock(struct rq
*rq
)
121 if (rq
->skip_clock_update
> 0)
124 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
126 update_rq_clock_task(rq
, delta
);
130 * Debugging: various feature bits
133 #define SCHED_FEAT(name, enabled) \
134 (1UL << __SCHED_FEAT_##name) * enabled |
136 const_debug
unsigned int sysctl_sched_features
=
137 #include "features.h"
142 #ifdef CONFIG_SCHED_DEBUG
143 #define SCHED_FEAT(name, enabled) \
146 static const char * const sched_feat_names
[] = {
147 #include "features.h"
152 static int sched_feat_show(struct seq_file
*m
, void *v
)
156 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
157 if (!(sysctl_sched_features
& (1UL << i
)))
159 seq_printf(m
, "%s ", sched_feat_names
[i
]);
166 #ifdef HAVE_JUMP_LABEL
168 #define jump_label_key__true STATIC_KEY_INIT_TRUE
169 #define jump_label_key__false STATIC_KEY_INIT_FALSE
171 #define SCHED_FEAT(name, enabled) \
172 jump_label_key__##enabled ,
174 struct static_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
175 #include "features.h"
180 static void sched_feat_disable(int i
)
182 if (static_key_enabled(&sched_feat_keys
[i
]))
183 static_key_slow_dec(&sched_feat_keys
[i
]);
186 static void sched_feat_enable(int i
)
188 if (!static_key_enabled(&sched_feat_keys
[i
]))
189 static_key_slow_inc(&sched_feat_keys
[i
]);
192 static void sched_feat_disable(int i
) { };
193 static void sched_feat_enable(int i
) { };
194 #endif /* HAVE_JUMP_LABEL */
196 static int sched_feat_set(char *cmp
)
201 if (strncmp(cmp
, "NO_", 3) == 0) {
206 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
207 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
209 sysctl_sched_features
&= ~(1UL << i
);
210 sched_feat_disable(i
);
212 sysctl_sched_features
|= (1UL << i
);
213 sched_feat_enable(i
);
223 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
224 size_t cnt
, loff_t
*ppos
)
233 if (copy_from_user(&buf
, ubuf
, cnt
))
239 i
= sched_feat_set(cmp
);
240 if (i
== __SCHED_FEAT_NR
)
248 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
250 return single_open(filp
, sched_feat_show
, NULL
);
253 static const struct file_operations sched_feat_fops
= {
254 .open
= sched_feat_open
,
255 .write
= sched_feat_write
,
258 .release
= single_release
,
261 static __init
int sched_init_debug(void)
263 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
268 late_initcall(sched_init_debug
);
269 #endif /* CONFIG_SCHED_DEBUG */
272 * Number of tasks to iterate in a single balance run.
273 * Limited because this is done with IRQs disabled.
275 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
278 * period over which we average the RT time consumption, measured
283 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
286 * period over which we measure -rt task cpu usage in us.
289 unsigned int sysctl_sched_rt_period
= 1000000;
291 __read_mostly
int scheduler_running
;
294 * part of the period that we allow rt tasks to run in us.
297 int sysctl_sched_rt_runtime
= 950000;
302 * __task_rq_lock - lock the rq @p resides on.
304 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
309 lockdep_assert_held(&p
->pi_lock
);
313 raw_spin_lock(&rq
->lock
);
314 if (likely(rq
== task_rq(p
)))
316 raw_spin_unlock(&rq
->lock
);
321 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
323 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
324 __acquires(p
->pi_lock
)
330 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
332 raw_spin_lock(&rq
->lock
);
333 if (likely(rq
== task_rq(p
)))
335 raw_spin_unlock(&rq
->lock
);
336 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
340 static void __task_rq_unlock(struct rq
*rq
)
343 raw_spin_unlock(&rq
->lock
);
347 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
349 __releases(p
->pi_lock
)
351 raw_spin_unlock(&rq
->lock
);
352 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
356 * this_rq_lock - lock this runqueue and disable interrupts.
358 static struct rq
*this_rq_lock(void)
365 raw_spin_lock(&rq
->lock
);
370 #ifdef CONFIG_SCHED_HRTICK
372 * Use HR-timers to deliver accurate preemption points.
375 static void hrtick_clear(struct rq
*rq
)
377 if (hrtimer_active(&rq
->hrtick_timer
))
378 hrtimer_cancel(&rq
->hrtick_timer
);
382 * High-resolution timer tick.
383 * Runs from hardirq context with interrupts disabled.
385 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
387 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
389 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
391 raw_spin_lock(&rq
->lock
);
393 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
394 raw_spin_unlock(&rq
->lock
);
396 return HRTIMER_NORESTART
;
401 static int __hrtick_restart(struct rq
*rq
)
403 struct hrtimer
*timer
= &rq
->hrtick_timer
;
404 ktime_t time
= hrtimer_get_softexpires(timer
);
406 return __hrtimer_start_range_ns(timer
, time
, 0, HRTIMER_MODE_ABS_PINNED
, 0);
410 * called from hardirq (IPI) context
412 static void __hrtick_start(void *arg
)
416 raw_spin_lock(&rq
->lock
);
417 __hrtick_restart(rq
);
418 rq
->hrtick_csd_pending
= 0;
419 raw_spin_unlock(&rq
->lock
);
423 * Called to set the hrtick timer state.
425 * called with rq->lock held and irqs disabled
427 void hrtick_start(struct rq
*rq
, u64 delay
)
429 struct hrtimer
*timer
= &rq
->hrtick_timer
;
430 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
432 hrtimer_set_expires(timer
, time
);
434 if (rq
== this_rq()) {
435 __hrtick_restart(rq
);
436 } else if (!rq
->hrtick_csd_pending
) {
437 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
438 rq
->hrtick_csd_pending
= 1;
443 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
445 int cpu
= (int)(long)hcpu
;
448 case CPU_UP_CANCELED
:
449 case CPU_UP_CANCELED_FROZEN
:
450 case CPU_DOWN_PREPARE
:
451 case CPU_DOWN_PREPARE_FROZEN
:
453 case CPU_DEAD_FROZEN
:
454 hrtick_clear(cpu_rq(cpu
));
461 static __init
void init_hrtick(void)
463 hotcpu_notifier(hotplug_hrtick
, 0);
467 * Called to set the hrtick timer state.
469 * called with rq->lock held and irqs disabled
471 void hrtick_start(struct rq
*rq
, u64 delay
)
473 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
474 HRTIMER_MODE_REL_PINNED
, 0);
477 static inline void init_hrtick(void)
480 #endif /* CONFIG_SMP */
482 static void init_rq_hrtick(struct rq
*rq
)
485 rq
->hrtick_csd_pending
= 0;
487 rq
->hrtick_csd
.flags
= 0;
488 rq
->hrtick_csd
.func
= __hrtick_start
;
489 rq
->hrtick_csd
.info
= rq
;
492 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
493 rq
->hrtick_timer
.function
= hrtick
;
495 #else /* CONFIG_SCHED_HRTICK */
496 static inline void hrtick_clear(struct rq
*rq
)
500 static inline void init_rq_hrtick(struct rq
*rq
)
504 static inline void init_hrtick(void)
507 #endif /* CONFIG_SCHED_HRTICK */
510 * resched_task - mark a task 'to be rescheduled now'.
512 * On UP this means the setting of the need_resched flag, on SMP it
513 * might also involve a cross-CPU call to trigger the scheduler on
517 void resched_task(struct task_struct
*p
)
521 assert_raw_spin_locked(&task_rq(p
)->lock
);
523 if (test_tsk_need_resched(p
))
526 set_tsk_need_resched(p
);
529 if (cpu
== smp_processor_id())
532 /* NEED_RESCHED must be visible before we test polling */
534 if (!tsk_is_polling(p
))
535 smp_send_reschedule(cpu
);
538 void resched_cpu(int cpu
)
540 struct rq
*rq
= cpu_rq(cpu
);
543 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
545 resched_task(cpu_curr(cpu
));
546 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
549 #ifdef CONFIG_NO_HZ_COMMON
551 * In the semi idle case, use the nearest busy cpu for migrating timers
552 * from an idle cpu. This is good for power-savings.
554 * We don't do similar optimization for completely idle system, as
555 * selecting an idle cpu will add more delays to the timers than intended
556 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
558 int get_nohz_timer_target(void)
560 int cpu
= smp_processor_id();
562 struct sched_domain
*sd
;
565 for_each_domain(cpu
, sd
) {
566 for_each_cpu(i
, sched_domain_span(sd
)) {
578 * When add_timer_on() enqueues a timer into the timer wheel of an
579 * idle CPU then this timer might expire before the next timer event
580 * which is scheduled to wake up that CPU. In case of a completely
581 * idle system the next event might even be infinite time into the
582 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
583 * leaves the inner idle loop so the newly added timer is taken into
584 * account when the CPU goes back to idle and evaluates the timer
585 * wheel for the next timer event.
587 static void wake_up_idle_cpu(int cpu
)
589 struct rq
*rq
= cpu_rq(cpu
);
591 if (cpu
== smp_processor_id())
595 * This is safe, as this function is called with the timer
596 * wheel base lock of (cpu) held. When the CPU is on the way
597 * to idle and has not yet set rq->curr to idle then it will
598 * be serialized on the timer wheel base lock and take the new
599 * timer into account automatically.
601 if (rq
->curr
!= rq
->idle
)
605 * We can set TIF_RESCHED on the idle task of the other CPU
606 * lockless. The worst case is that the other CPU runs the
607 * idle task through an additional NOOP schedule()
609 set_tsk_need_resched(rq
->idle
);
611 /* NEED_RESCHED must be visible before we test polling */
613 if (!tsk_is_polling(rq
->idle
))
614 smp_send_reschedule(cpu
);
617 static bool wake_up_full_nohz_cpu(int cpu
)
619 if (tick_nohz_full_cpu(cpu
)) {
620 if (cpu
!= smp_processor_id() ||
621 tick_nohz_tick_stopped())
622 smp_send_reschedule(cpu
);
629 void wake_up_nohz_cpu(int cpu
)
631 if (!wake_up_full_nohz_cpu(cpu
))
632 wake_up_idle_cpu(cpu
);
635 static inline bool got_nohz_idle_kick(void)
637 int cpu
= smp_processor_id();
639 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
642 if (idle_cpu(cpu
) && !need_resched())
646 * We can't run Idle Load Balance on this CPU for this time so we
647 * cancel it and clear NOHZ_BALANCE_KICK
649 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
653 #else /* CONFIG_NO_HZ_COMMON */
655 static inline bool got_nohz_idle_kick(void)
660 #endif /* CONFIG_NO_HZ_COMMON */
662 #ifdef CONFIG_NO_HZ_FULL
663 bool sched_can_stop_tick(void)
669 /* Make sure rq->nr_running update is visible after the IPI */
672 /* More than one running task need preemption */
673 if (rq
->nr_running
> 1)
678 #endif /* CONFIG_NO_HZ_FULL */
680 void sched_avg_update(struct rq
*rq
)
682 s64 period
= sched_avg_period();
684 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
686 * Inline assembly required to prevent the compiler
687 * optimising this loop into a divmod call.
688 * See __iter_div_u64_rem() for another example of this.
690 asm("" : "+rm" (rq
->age_stamp
));
691 rq
->age_stamp
+= period
;
696 #else /* !CONFIG_SMP */
697 void resched_task(struct task_struct
*p
)
699 assert_raw_spin_locked(&task_rq(p
)->lock
);
700 set_tsk_need_resched(p
);
702 #endif /* CONFIG_SMP */
704 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
705 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
707 * Iterate task_group tree rooted at *from, calling @down when first entering a
708 * node and @up when leaving it for the final time.
710 * Caller must hold rcu_lock or sufficient equivalent.
712 int walk_tg_tree_from(struct task_group
*from
,
713 tg_visitor down
, tg_visitor up
, void *data
)
715 struct task_group
*parent
, *child
;
721 ret
= (*down
)(parent
, data
);
724 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
731 ret
= (*up
)(parent
, data
);
732 if (ret
|| parent
== from
)
736 parent
= parent
->parent
;
743 int tg_nop(struct task_group
*tg
, void *data
)
749 static void set_load_weight(struct task_struct
*p
)
751 int prio
= p
->static_prio
- MAX_RT_PRIO
;
752 struct load_weight
*load
= &p
->se
.load
;
755 * SCHED_IDLE tasks get minimal weight:
757 if (p
->policy
== SCHED_IDLE
) {
758 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
759 load
->inv_weight
= WMULT_IDLEPRIO
;
763 load
->weight
= scale_load(prio_to_weight
[prio
]);
764 load
->inv_weight
= prio_to_wmult
[prio
];
767 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
770 sched_info_queued(p
);
771 p
->sched_class
->enqueue_task(rq
, p
, flags
);
774 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
777 sched_info_dequeued(p
);
778 p
->sched_class
->dequeue_task(rq
, p
, flags
);
781 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
783 if (task_contributes_to_load(p
))
784 rq
->nr_uninterruptible
--;
786 enqueue_task(rq
, p
, flags
);
789 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
791 if (task_contributes_to_load(p
))
792 rq
->nr_uninterruptible
++;
794 dequeue_task(rq
, p
, flags
);
797 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
800 * In theory, the compile should just see 0 here, and optimize out the call
801 * to sched_rt_avg_update. But I don't trust it...
803 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
804 s64 steal
= 0, irq_delta
= 0;
806 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
807 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
810 * Since irq_time is only updated on {soft,}irq_exit, we might run into
811 * this case when a previous update_rq_clock() happened inside a
814 * When this happens, we stop ->clock_task and only update the
815 * prev_irq_time stamp to account for the part that fit, so that a next
816 * update will consume the rest. This ensures ->clock_task is
819 * It does however cause some slight miss-attribution of {soft,}irq
820 * time, a more accurate solution would be to update the irq_time using
821 * the current rq->clock timestamp, except that would require using
824 if (irq_delta
> delta
)
827 rq
->prev_irq_time
+= irq_delta
;
830 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
831 if (static_key_false((¶virt_steal_rq_enabled
))) {
834 steal
= paravirt_steal_clock(cpu_of(rq
));
835 steal
-= rq
->prev_steal_time_rq
;
837 if (unlikely(steal
> delta
))
840 st
= steal_ticks(steal
);
841 steal
= st
* TICK_NSEC
;
843 rq
->prev_steal_time_rq
+= steal
;
849 rq
->clock_task
+= delta
;
851 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
852 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
853 sched_rt_avg_update(rq
, irq_delta
+ steal
);
857 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
859 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
860 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
864 * Make it appear like a SCHED_FIFO task, its something
865 * userspace knows about and won't get confused about.
867 * Also, it will make PI more or less work without too
868 * much confusion -- but then, stop work should not
869 * rely on PI working anyway.
871 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
873 stop
->sched_class
= &stop_sched_class
;
876 cpu_rq(cpu
)->stop
= stop
;
880 * Reset it back to a normal scheduling class so that
881 * it can die in pieces.
883 old_stop
->sched_class
= &rt_sched_class
;
888 * __normal_prio - return the priority that is based on the static prio
890 static inline int __normal_prio(struct task_struct
*p
)
892 return p
->static_prio
;
896 * Calculate the expected normal priority: i.e. priority
897 * without taking RT-inheritance into account. Might be
898 * boosted by interactivity modifiers. Changes upon fork,
899 * setprio syscalls, and whenever the interactivity
900 * estimator recalculates.
902 static inline int normal_prio(struct task_struct
*p
)
906 if (task_has_rt_policy(p
))
907 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
909 prio
= __normal_prio(p
);
914 * Calculate the current priority, i.e. the priority
915 * taken into account by the scheduler. This value might
916 * be boosted by RT tasks, or might be boosted by
917 * interactivity modifiers. Will be RT if the task got
918 * RT-boosted. If not then it returns p->normal_prio.
920 static int effective_prio(struct task_struct
*p
)
922 p
->normal_prio
= normal_prio(p
);
924 * If we are RT tasks or we were boosted to RT priority,
925 * keep the priority unchanged. Otherwise, update priority
926 * to the normal priority:
928 if (!rt_prio(p
->prio
))
929 return p
->normal_prio
;
934 * task_curr - is this task currently executing on a CPU?
935 * @p: the task in question.
937 * Return: 1 if the task is currently executing. 0 otherwise.
939 inline int task_curr(const struct task_struct
*p
)
941 return cpu_curr(task_cpu(p
)) == p
;
944 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
945 const struct sched_class
*prev_class
,
948 if (prev_class
!= p
->sched_class
) {
949 if (prev_class
->switched_from
)
950 prev_class
->switched_from(rq
, p
);
951 p
->sched_class
->switched_to(rq
, p
);
952 } else if (oldprio
!= p
->prio
)
953 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
956 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
958 const struct sched_class
*class;
960 if (p
->sched_class
== rq
->curr
->sched_class
) {
961 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
963 for_each_class(class) {
964 if (class == rq
->curr
->sched_class
)
966 if (class == p
->sched_class
) {
967 resched_task(rq
->curr
);
974 * A queue event has occurred, and we're going to schedule. In
975 * this case, we can save a useless back to back clock update.
977 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
978 rq
->skip_clock_update
= 1;
981 static ATOMIC_NOTIFIER_HEAD(task_migration_notifier
);
983 void register_task_migration_notifier(struct notifier_block
*n
)
985 atomic_notifier_chain_register(&task_migration_notifier
, n
);
989 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
991 #ifdef CONFIG_SCHED_DEBUG
993 * We should never call set_task_cpu() on a blocked task,
994 * ttwu() will sort out the placement.
996 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
997 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
999 #ifdef CONFIG_LOCKDEP
1001 * The caller should hold either p->pi_lock or rq->lock, when changing
1002 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1004 * sched_move_task() holds both and thus holding either pins the cgroup,
1007 * Furthermore, all task_rq users should acquire both locks, see
1010 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1011 lockdep_is_held(&task_rq(p
)->lock
)));
1015 trace_sched_migrate_task(p
, new_cpu
);
1017 if (task_cpu(p
) != new_cpu
) {
1018 struct task_migration_notifier tmn
;
1020 if (p
->sched_class
->migrate_task_rq
)
1021 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1022 p
->se
.nr_migrations
++;
1023 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1026 tmn
.from_cpu
= task_cpu(p
);
1027 tmn
.to_cpu
= new_cpu
;
1029 atomic_notifier_call_chain(&task_migration_notifier
, 0, &tmn
);
1032 __set_task_cpu(p
, new_cpu
);
1035 struct migration_arg
{
1036 struct task_struct
*task
;
1040 static int migration_cpu_stop(void *data
);
1043 * wait_task_inactive - wait for a thread to unschedule.
1045 * If @match_state is nonzero, it's the @p->state value just checked and
1046 * not expected to change. If it changes, i.e. @p might have woken up,
1047 * then return zero. When we succeed in waiting for @p to be off its CPU,
1048 * we return a positive number (its total switch count). If a second call
1049 * a short while later returns the same number, the caller can be sure that
1050 * @p has remained unscheduled the whole time.
1052 * The caller must ensure that the task *will* unschedule sometime soon,
1053 * else this function might spin for a *long* time. This function can't
1054 * be called with interrupts off, or it may introduce deadlock with
1055 * smp_call_function() if an IPI is sent by the same process we are
1056 * waiting to become inactive.
1058 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1060 unsigned long flags
;
1067 * We do the initial early heuristics without holding
1068 * any task-queue locks at all. We'll only try to get
1069 * the runqueue lock when things look like they will
1075 * If the task is actively running on another CPU
1076 * still, just relax and busy-wait without holding
1079 * NOTE! Since we don't hold any locks, it's not
1080 * even sure that "rq" stays as the right runqueue!
1081 * But we don't care, since "task_running()" will
1082 * return false if the runqueue has changed and p
1083 * is actually now running somewhere else!
1085 while (task_running(rq
, p
)) {
1086 if (match_state
&& unlikely(p
->state
!= match_state
))
1092 * Ok, time to look more closely! We need the rq
1093 * lock now, to be *sure*. If we're wrong, we'll
1094 * just go back and repeat.
1096 rq
= task_rq_lock(p
, &flags
);
1097 trace_sched_wait_task(p
);
1098 running
= task_running(rq
, p
);
1101 if (!match_state
|| p
->state
== match_state
)
1102 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1103 task_rq_unlock(rq
, p
, &flags
);
1106 * If it changed from the expected state, bail out now.
1108 if (unlikely(!ncsw
))
1112 * Was it really running after all now that we
1113 * checked with the proper locks actually held?
1115 * Oops. Go back and try again..
1117 if (unlikely(running
)) {
1123 * It's not enough that it's not actively running,
1124 * it must be off the runqueue _entirely_, and not
1127 * So if it was still runnable (but just not actively
1128 * running right now), it's preempted, and we should
1129 * yield - it could be a while.
1131 if (unlikely(on_rq
)) {
1132 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1134 set_current_state(TASK_UNINTERRUPTIBLE
);
1135 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1140 * Ahh, all good. It wasn't running, and it wasn't
1141 * runnable, which means that it will never become
1142 * running in the future either. We're all done!
1151 * kick_process - kick a running thread to enter/exit the kernel
1152 * @p: the to-be-kicked thread
1154 * Cause a process which is running on another CPU to enter
1155 * kernel-mode, without any delay. (to get signals handled.)
1157 * NOTE: this function doesn't have to take the runqueue lock,
1158 * because all it wants to ensure is that the remote task enters
1159 * the kernel. If the IPI races and the task has been migrated
1160 * to another CPU then no harm is done and the purpose has been
1163 void kick_process(struct task_struct
*p
)
1169 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1170 smp_send_reschedule(cpu
);
1173 EXPORT_SYMBOL_GPL(kick_process
);
1174 #endif /* CONFIG_SMP */
1178 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1180 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1182 int nid
= cpu_to_node(cpu
);
1183 const struct cpumask
*nodemask
= NULL
;
1184 enum { cpuset
, possible
, fail
} state
= cpuset
;
1188 * If the node that the cpu is on has been offlined, cpu_to_node()
1189 * will return -1. There is no cpu on the node, and we should
1190 * select the cpu on the other node.
1193 nodemask
= cpumask_of_node(nid
);
1195 /* Look for allowed, online CPU in same node. */
1196 for_each_cpu(dest_cpu
, nodemask
) {
1197 if (!cpu_online(dest_cpu
))
1199 if (!cpu_active(dest_cpu
))
1201 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1207 /* Any allowed, online CPU? */
1208 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1209 if (!cpu_online(dest_cpu
))
1211 if (!cpu_active(dest_cpu
))
1218 /* No more Mr. Nice Guy. */
1219 cpuset_cpus_allowed_fallback(p
);
1224 do_set_cpus_allowed(p
, cpu_possible_mask
);
1235 if (state
!= cpuset
) {
1237 * Don't tell them about moving exiting tasks or
1238 * kernel threads (both mm NULL), since they never
1241 if (p
->mm
&& printk_ratelimit()) {
1242 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1243 task_pid_nr(p
), p
->comm
, cpu
);
1251 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1254 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
1256 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
1259 * In order not to call set_task_cpu() on a blocking task we need
1260 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1263 * Since this is common to all placement strategies, this lives here.
1265 * [ this allows ->select_task() to simply return task_cpu(p) and
1266 * not worry about this generic constraint ]
1268 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1270 cpu
= select_fallback_rq(task_cpu(p
), p
);
1275 static void update_avg(u64
*avg
, u64 sample
)
1277 s64 diff
= sample
- *avg
;
1283 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1285 #ifdef CONFIG_SCHEDSTATS
1286 struct rq
*rq
= this_rq();
1289 int this_cpu
= smp_processor_id();
1291 if (cpu
== this_cpu
) {
1292 schedstat_inc(rq
, ttwu_local
);
1293 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1295 struct sched_domain
*sd
;
1297 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1299 for_each_domain(this_cpu
, sd
) {
1300 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1301 schedstat_inc(sd
, ttwu_wake_remote
);
1308 if (wake_flags
& WF_MIGRATED
)
1309 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1311 #endif /* CONFIG_SMP */
1313 schedstat_inc(rq
, ttwu_count
);
1314 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1316 if (wake_flags
& WF_SYNC
)
1317 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1319 #endif /* CONFIG_SCHEDSTATS */
1322 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1324 activate_task(rq
, p
, en_flags
);
1327 /* if a worker is waking up, notify workqueue */
1328 if (p
->flags
& PF_WQ_WORKER
)
1329 wq_worker_waking_up(p
, cpu_of(rq
));
1333 * Mark the task runnable and perform wakeup-preemption.
1336 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1338 check_preempt_curr(rq
, p
, wake_flags
);
1339 trace_sched_wakeup(p
, true);
1341 p
->state
= TASK_RUNNING
;
1343 if (p
->sched_class
->task_woken
)
1344 p
->sched_class
->task_woken(rq
, p
);
1346 if (rq
->idle_stamp
) {
1347 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1348 u64 max
= 2*sysctl_sched_migration_cost
;
1353 update_avg(&rq
->avg_idle
, delta
);
1360 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1363 if (p
->sched_contributes_to_load
)
1364 rq
->nr_uninterruptible
--;
1367 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1368 ttwu_do_wakeup(rq
, p
, wake_flags
);
1372 * Called in case the task @p isn't fully descheduled from its runqueue,
1373 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1374 * since all we need to do is flip p->state to TASK_RUNNING, since
1375 * the task is still ->on_rq.
1377 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1382 rq
= __task_rq_lock(p
);
1384 /* check_preempt_curr() may use rq clock */
1385 update_rq_clock(rq
);
1386 ttwu_do_wakeup(rq
, p
, wake_flags
);
1389 __task_rq_unlock(rq
);
1395 static void sched_ttwu_pending(void)
1397 struct rq
*rq
= this_rq();
1398 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1399 struct task_struct
*p
;
1401 raw_spin_lock(&rq
->lock
);
1404 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1405 llist
= llist_next(llist
);
1406 ttwu_do_activate(rq
, p
, 0);
1409 raw_spin_unlock(&rq
->lock
);
1412 void scheduler_ipi(void)
1414 if (llist_empty(&this_rq()->wake_list
)
1415 && !tick_nohz_full_cpu(smp_processor_id())
1416 && !got_nohz_idle_kick())
1420 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1421 * traditionally all their work was done from the interrupt return
1422 * path. Now that we actually do some work, we need to make sure
1425 * Some archs already do call them, luckily irq_enter/exit nest
1428 * Arguably we should visit all archs and update all handlers,
1429 * however a fair share of IPIs are still resched only so this would
1430 * somewhat pessimize the simple resched case.
1433 tick_nohz_full_check();
1434 sched_ttwu_pending();
1437 * Check if someone kicked us for doing the nohz idle load balance.
1439 if (unlikely(got_nohz_idle_kick())) {
1440 this_rq()->idle_balance
= 1;
1441 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1446 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1448 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
1449 smp_send_reschedule(cpu
);
1452 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1454 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1456 #endif /* CONFIG_SMP */
1458 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1460 struct rq
*rq
= cpu_rq(cpu
);
1462 #if defined(CONFIG_SMP)
1463 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1464 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1465 ttwu_queue_remote(p
, cpu
);
1470 raw_spin_lock(&rq
->lock
);
1471 ttwu_do_activate(rq
, p
, 0);
1472 raw_spin_unlock(&rq
->lock
);
1476 * try_to_wake_up - wake up a thread
1477 * @p: the thread to be awakened
1478 * @state: the mask of task states that can be woken
1479 * @wake_flags: wake modifier flags (WF_*)
1481 * Put it on the run-queue if it's not already there. The "current"
1482 * thread is always on the run-queue (except when the actual
1483 * re-schedule is in progress), and as such you're allowed to do
1484 * the simpler "current->state = TASK_RUNNING" to mark yourself
1485 * runnable without the overhead of this.
1487 * Return: %true if @p was woken up, %false if it was already running.
1488 * or @state didn't match @p's state.
1491 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1493 unsigned long flags
;
1494 int cpu
, success
= 0;
1497 * If we are going to wake up a thread waiting for CONDITION we
1498 * need to ensure that CONDITION=1 done by the caller can not be
1499 * reordered with p->state check below. This pairs with mb() in
1500 * set_current_state() the waiting thread does.
1502 smp_mb__before_spinlock();
1503 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1504 if (!(p
->state
& state
))
1507 success
= 1; /* we're going to change ->state */
1510 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1515 * If the owning (remote) cpu is still in the middle of schedule() with
1516 * this task as prev, wait until its done referencing the task.
1521 * Pairs with the smp_wmb() in finish_lock_switch().
1525 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1526 p
->state
= TASK_WAKING
;
1528 if (p
->sched_class
->task_waking
)
1529 p
->sched_class
->task_waking(p
);
1531 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
1532 if (task_cpu(p
) != cpu
) {
1533 wake_flags
|= WF_MIGRATED
;
1534 set_task_cpu(p
, cpu
);
1536 #endif /* CONFIG_SMP */
1540 ttwu_stat(p
, cpu
, wake_flags
);
1542 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1548 * try_to_wake_up_local - try to wake up a local task with rq lock held
1549 * @p: the thread to be awakened
1551 * Put @p on the run-queue if it's not already there. The caller must
1552 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1555 static void try_to_wake_up_local(struct task_struct
*p
)
1557 struct rq
*rq
= task_rq(p
);
1559 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1560 WARN_ON_ONCE(p
== current
))
1563 lockdep_assert_held(&rq
->lock
);
1565 if (!raw_spin_trylock(&p
->pi_lock
)) {
1566 raw_spin_unlock(&rq
->lock
);
1567 raw_spin_lock(&p
->pi_lock
);
1568 raw_spin_lock(&rq
->lock
);
1571 if (!(p
->state
& TASK_NORMAL
))
1575 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1577 ttwu_do_wakeup(rq
, p
, 0);
1578 ttwu_stat(p
, smp_processor_id(), 0);
1580 raw_spin_unlock(&p
->pi_lock
);
1584 * wake_up_process - Wake up a specific process
1585 * @p: The process to be woken up.
1587 * Attempt to wake up the nominated process and move it to the set of runnable
1590 * Return: 1 if the process was woken up, 0 if it was already running.
1592 * It may be assumed that this function implies a write memory barrier before
1593 * changing the task state if and only if any tasks are woken up.
1595 int wake_up_process(struct task_struct
*p
)
1597 WARN_ON(task_is_stopped_or_traced(p
));
1598 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1600 EXPORT_SYMBOL(wake_up_process
);
1602 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1604 return try_to_wake_up(p
, state
, 0);
1608 * Perform scheduler related setup for a newly forked process p.
1609 * p is forked by current.
1611 * __sched_fork() is basic setup used by init_idle() too:
1613 static void __sched_fork(struct task_struct
*p
)
1618 p
->se
.exec_start
= 0;
1619 p
->se
.sum_exec_runtime
= 0;
1620 p
->se
.prev_sum_exec_runtime
= 0;
1621 p
->se
.nr_migrations
= 0;
1623 INIT_LIST_HEAD(&p
->se
.group_node
);
1625 #ifdef CONFIG_SCHEDSTATS
1626 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1629 INIT_LIST_HEAD(&p
->rt
.run_list
);
1631 #ifdef CONFIG_PREEMPT_NOTIFIERS
1632 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1635 #ifdef CONFIG_NUMA_BALANCING
1636 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1637 p
->mm
->numa_next_scan
= jiffies
;
1638 p
->mm
->numa_next_reset
= jiffies
;
1639 p
->mm
->numa_scan_seq
= 0;
1642 p
->node_stamp
= 0ULL;
1643 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1644 p
->numa_migrate_seq
= p
->mm
? p
->mm
->numa_scan_seq
- 1 : 0;
1645 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1646 p
->numa_work
.next
= &p
->numa_work
;
1647 #endif /* CONFIG_NUMA_BALANCING */
1650 #ifdef CONFIG_NUMA_BALANCING
1651 #ifdef CONFIG_SCHED_DEBUG
1652 void set_numabalancing_state(bool enabled
)
1655 sched_feat_set("NUMA");
1657 sched_feat_set("NO_NUMA");
1660 __read_mostly
bool numabalancing_enabled
;
1662 void set_numabalancing_state(bool enabled
)
1664 numabalancing_enabled
= enabled
;
1666 #endif /* CONFIG_SCHED_DEBUG */
1667 #endif /* CONFIG_NUMA_BALANCING */
1670 * fork()/clone()-time setup:
1672 void sched_fork(struct task_struct
*p
)
1674 unsigned long flags
;
1675 int cpu
= get_cpu();
1679 * We mark the process as running here. This guarantees that
1680 * nobody will actually run it, and a signal or other external
1681 * event cannot wake it up and insert it on the runqueue either.
1683 p
->state
= TASK_RUNNING
;
1686 * Make sure we do not leak PI boosting priority to the child.
1688 p
->prio
= current
->normal_prio
;
1691 * Revert to default priority/policy on fork if requested.
1693 if (unlikely(p
->sched_reset_on_fork
)) {
1694 if (task_has_rt_policy(p
)) {
1695 p
->policy
= SCHED_NORMAL
;
1696 p
->static_prio
= NICE_TO_PRIO(0);
1698 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1699 p
->static_prio
= NICE_TO_PRIO(0);
1701 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1705 * We don't need the reset flag anymore after the fork. It has
1706 * fulfilled its duty:
1708 p
->sched_reset_on_fork
= 0;
1711 if (!rt_prio(p
->prio
))
1712 p
->sched_class
= &fair_sched_class
;
1714 if (p
->sched_class
->task_fork
)
1715 p
->sched_class
->task_fork(p
);
1718 * The child is not yet in the pid-hash so no cgroup attach races,
1719 * and the cgroup is pinned to this child due to cgroup_fork()
1720 * is ran before sched_fork().
1722 * Silence PROVE_RCU.
1724 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1725 set_task_cpu(p
, cpu
);
1726 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1728 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1729 if (likely(sched_info_on()))
1730 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1732 #if defined(CONFIG_SMP)
1735 #ifdef CONFIG_PREEMPT_COUNT
1736 /* Want to start with kernel preemption disabled. */
1737 task_thread_info(p
)->preempt_count
= 1;
1740 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1747 * wake_up_new_task - wake up a newly created task for the first time.
1749 * This function will do some initial scheduler statistics housekeeping
1750 * that must be done for every newly created context, then puts the task
1751 * on the runqueue and wakes it.
1753 void wake_up_new_task(struct task_struct
*p
)
1755 unsigned long flags
;
1758 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1761 * Fork balancing, do it here and not earlier because:
1762 * - cpus_allowed can change in the fork path
1763 * - any previously selected cpu might disappear through hotplug
1765 set_task_cpu(p
, select_task_rq(p
, SD_BALANCE_FORK
, 0));
1768 /* Initialize new task's runnable average */
1769 init_task_runnable_average(p
);
1770 rq
= __task_rq_lock(p
);
1771 activate_task(rq
, p
, 0);
1773 trace_sched_wakeup_new(p
, true);
1774 check_preempt_curr(rq
, p
, WF_FORK
);
1776 if (p
->sched_class
->task_woken
)
1777 p
->sched_class
->task_woken(rq
, p
);
1779 task_rq_unlock(rq
, p
, &flags
);
1782 #ifdef CONFIG_PREEMPT_NOTIFIERS
1785 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1786 * @notifier: notifier struct to register
1788 void preempt_notifier_register(struct preempt_notifier
*notifier
)
1790 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
1792 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
1795 * preempt_notifier_unregister - no longer interested in preemption notifications
1796 * @notifier: notifier struct to unregister
1798 * This is safe to call from within a preemption notifier.
1800 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
1802 hlist_del(¬ifier
->link
);
1804 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
1806 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1808 struct preempt_notifier
*notifier
;
1810 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
1811 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
1815 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1816 struct task_struct
*next
)
1818 struct preempt_notifier
*notifier
;
1820 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
1821 notifier
->ops
->sched_out(notifier
, next
);
1824 #else /* !CONFIG_PREEMPT_NOTIFIERS */
1826 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1831 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1832 struct task_struct
*next
)
1836 #endif /* CONFIG_PREEMPT_NOTIFIERS */
1839 * prepare_task_switch - prepare to switch tasks
1840 * @rq: the runqueue preparing to switch
1841 * @prev: the current task that is being switched out
1842 * @next: the task we are going to switch to.
1844 * This is called with the rq lock held and interrupts off. It must
1845 * be paired with a subsequent finish_task_switch after the context
1848 * prepare_task_switch sets up locking and calls architecture specific
1852 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
1853 struct task_struct
*next
)
1855 trace_sched_switch(prev
, next
);
1856 sched_info_switch(prev
, next
);
1857 perf_event_task_sched_out(prev
, next
);
1858 fire_sched_out_preempt_notifiers(prev
, next
);
1859 prepare_lock_switch(rq
, next
);
1860 prepare_arch_switch(next
);
1864 * finish_task_switch - clean up after a task-switch
1865 * @rq: runqueue associated with task-switch
1866 * @prev: the thread we just switched away from.
1868 * finish_task_switch must be called after the context switch, paired
1869 * with a prepare_task_switch call before the context switch.
1870 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1871 * and do any other architecture-specific cleanup actions.
1873 * Note that we may have delayed dropping an mm in context_switch(). If
1874 * so, we finish that here outside of the runqueue lock. (Doing it
1875 * with the lock held can cause deadlocks; see schedule() for
1878 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
1879 __releases(rq
->lock
)
1881 struct mm_struct
*mm
= rq
->prev_mm
;
1887 * A task struct has one reference for the use as "current".
1888 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1889 * schedule one last time. The schedule call will never return, and
1890 * the scheduled task must drop that reference.
1891 * The test for TASK_DEAD must occur while the runqueue locks are
1892 * still held, otherwise prev could be scheduled on another cpu, die
1893 * there before we look at prev->state, and then the reference would
1895 * Manfred Spraul <manfred@colorfullife.com>
1897 prev_state
= prev
->state
;
1898 vtime_task_switch(prev
);
1899 finish_arch_switch(prev
);
1900 perf_event_task_sched_in(prev
, current
);
1901 finish_lock_switch(rq
, prev
);
1902 finish_arch_post_lock_switch();
1904 fire_sched_in_preempt_notifiers(current
);
1907 if (unlikely(prev_state
== TASK_DEAD
)) {
1909 * Remove function-return probe instances associated with this
1910 * task and put them back on the free list.
1912 kprobe_flush_task(prev
);
1913 put_task_struct(prev
);
1916 tick_nohz_task_switch(current
);
1921 /* assumes rq->lock is held */
1922 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
1924 if (prev
->sched_class
->pre_schedule
)
1925 prev
->sched_class
->pre_schedule(rq
, prev
);
1928 /* rq->lock is NOT held, but preemption is disabled */
1929 static inline void post_schedule(struct rq
*rq
)
1931 if (rq
->post_schedule
) {
1932 unsigned long flags
;
1934 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1935 if (rq
->curr
->sched_class
->post_schedule
)
1936 rq
->curr
->sched_class
->post_schedule(rq
);
1937 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1939 rq
->post_schedule
= 0;
1945 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
1949 static inline void post_schedule(struct rq
*rq
)
1956 * schedule_tail - first thing a freshly forked thread must call.
1957 * @prev: the thread we just switched away from.
1959 asmlinkage
void schedule_tail(struct task_struct
*prev
)
1960 __releases(rq
->lock
)
1962 struct rq
*rq
= this_rq();
1964 finish_task_switch(rq
, prev
);
1967 * FIXME: do we need to worry about rq being invalidated by the
1972 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
1973 /* In this case, finish_task_switch does not reenable preemption */
1976 if (current
->set_child_tid
)
1977 put_user(task_pid_vnr(current
), current
->set_child_tid
);
1981 * context_switch - switch to the new MM and the new
1982 * thread's register state.
1985 context_switch(struct rq
*rq
, struct task_struct
*prev
,
1986 struct task_struct
*next
)
1988 struct mm_struct
*mm
, *oldmm
;
1990 prepare_task_switch(rq
, prev
, next
);
1993 oldmm
= prev
->active_mm
;
1995 * For paravirt, this is coupled with an exit in switch_to to
1996 * combine the page table reload and the switch backend into
1999 arch_start_context_switch(prev
);
2002 next
->active_mm
= oldmm
;
2003 atomic_inc(&oldmm
->mm_count
);
2004 enter_lazy_tlb(oldmm
, next
);
2006 switch_mm(oldmm
, mm
, next
);
2009 prev
->active_mm
= NULL
;
2010 rq
->prev_mm
= oldmm
;
2013 * Since the runqueue lock will be released by the next
2014 * task (which is an invalid locking op but in the case
2015 * of the scheduler it's an obvious special-case), so we
2016 * do an early lockdep release here:
2018 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2019 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2022 context_tracking_task_switch(prev
, next
);
2023 /* Here we just switch the register state and the stack. */
2024 switch_to(prev
, next
, prev
);
2028 * this_rq must be evaluated again because prev may have moved
2029 * CPUs since it called schedule(), thus the 'rq' on its stack
2030 * frame will be invalid.
2032 finish_task_switch(this_rq(), prev
);
2036 * nr_running and nr_context_switches:
2038 * externally visible scheduler statistics: current number of runnable
2039 * threads, total number of context switches performed since bootup.
2041 unsigned long nr_running(void)
2043 unsigned long i
, sum
= 0;
2045 for_each_online_cpu(i
)
2046 sum
+= cpu_rq(i
)->nr_running
;
2051 unsigned long long nr_context_switches(void)
2054 unsigned long long sum
= 0;
2056 for_each_possible_cpu(i
)
2057 sum
+= cpu_rq(i
)->nr_switches
;
2062 unsigned long nr_iowait(void)
2064 unsigned long i
, sum
= 0;
2066 for_each_possible_cpu(i
)
2067 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2072 unsigned long nr_iowait_cpu(int cpu
)
2074 struct rq
*this = cpu_rq(cpu
);
2075 return atomic_read(&this->nr_iowait
);
2081 * sched_exec - execve() is a valuable balancing opportunity, because at
2082 * this point the task has the smallest effective memory and cache footprint.
2084 void sched_exec(void)
2086 struct task_struct
*p
= current
;
2087 unsigned long flags
;
2090 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2091 dest_cpu
= p
->sched_class
->select_task_rq(p
, SD_BALANCE_EXEC
, 0);
2092 if (dest_cpu
== smp_processor_id())
2095 if (likely(cpu_active(dest_cpu
))) {
2096 struct migration_arg arg
= { p
, dest_cpu
};
2098 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2099 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2103 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2108 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2109 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2111 EXPORT_PER_CPU_SYMBOL(kstat
);
2112 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2115 * Return any ns on the sched_clock that have not yet been accounted in
2116 * @p in case that task is currently running.
2118 * Called with task_rq_lock() held on @rq.
2120 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2124 if (task_current(rq
, p
)) {
2125 update_rq_clock(rq
);
2126 ns
= rq_clock_task(rq
) - p
->se
.exec_start
;
2134 unsigned long long task_delta_exec(struct task_struct
*p
)
2136 unsigned long flags
;
2140 rq
= task_rq_lock(p
, &flags
);
2141 ns
= do_task_delta_exec(p
, rq
);
2142 task_rq_unlock(rq
, p
, &flags
);
2148 * Return accounted runtime for the task.
2149 * In case the task is currently running, return the runtime plus current's
2150 * pending runtime that have not been accounted yet.
2152 unsigned long long task_sched_runtime(struct task_struct
*p
)
2154 unsigned long flags
;
2158 rq
= task_rq_lock(p
, &flags
);
2159 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2160 task_rq_unlock(rq
, p
, &flags
);
2166 * This function gets called by the timer code, with HZ frequency.
2167 * We call it with interrupts disabled.
2169 void scheduler_tick(void)
2171 int cpu
= smp_processor_id();
2172 struct rq
*rq
= cpu_rq(cpu
);
2173 struct task_struct
*curr
= rq
->curr
;
2177 raw_spin_lock(&rq
->lock
);
2178 update_rq_clock(rq
);
2179 curr
->sched_class
->task_tick(rq
, curr
, 0);
2180 update_cpu_load_active(rq
);
2181 raw_spin_unlock(&rq
->lock
);
2183 perf_event_task_tick();
2186 rq
->idle_balance
= idle_cpu(cpu
);
2187 trigger_load_balance(rq
, cpu
);
2189 rq_last_tick_reset(rq
);
2192 #ifdef CONFIG_NO_HZ_FULL
2194 * scheduler_tick_max_deferment
2196 * Keep at least one tick per second when a single
2197 * active task is running because the scheduler doesn't
2198 * yet completely support full dynticks environment.
2200 * This makes sure that uptime, CFS vruntime, load
2201 * balancing, etc... continue to move forward, even
2202 * with a very low granularity.
2204 * Return: Maximum deferment in nanoseconds.
2206 u64
scheduler_tick_max_deferment(void)
2208 struct rq
*rq
= this_rq();
2209 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2211 next
= rq
->last_sched_tick
+ HZ
;
2213 if (time_before_eq(next
, now
))
2216 return jiffies_to_usecs(next
- now
) * NSEC_PER_USEC
;
2220 notrace
unsigned long get_parent_ip(unsigned long addr
)
2222 if (in_lock_functions(addr
)) {
2223 addr
= CALLER_ADDR2
;
2224 if (in_lock_functions(addr
))
2225 addr
= CALLER_ADDR3
;
2230 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2231 defined(CONFIG_PREEMPT_TRACER))
2233 void __kprobes
add_preempt_count(int val
)
2235 #ifdef CONFIG_DEBUG_PREEMPT
2239 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2242 preempt_count() += val
;
2243 #ifdef CONFIG_DEBUG_PREEMPT
2245 * Spinlock count overflowing soon?
2247 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2250 if (preempt_count() == val
)
2251 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2253 EXPORT_SYMBOL(add_preempt_count
);
2255 void __kprobes
sub_preempt_count(int val
)
2257 #ifdef CONFIG_DEBUG_PREEMPT
2261 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2264 * Is the spinlock portion underflowing?
2266 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2267 !(preempt_count() & PREEMPT_MASK
)))
2271 if (preempt_count() == val
)
2272 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2273 preempt_count() -= val
;
2275 EXPORT_SYMBOL(sub_preempt_count
);
2280 * Print scheduling while atomic bug:
2282 static noinline
void __schedule_bug(struct task_struct
*prev
)
2284 if (oops_in_progress
)
2287 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2288 prev
->comm
, prev
->pid
, preempt_count());
2290 debug_show_held_locks(prev
);
2292 if (irqs_disabled())
2293 print_irqtrace_events(prev
);
2295 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2299 * Various schedule()-time debugging checks and statistics:
2301 static inline void schedule_debug(struct task_struct
*prev
)
2304 * Test if we are atomic. Since do_exit() needs to call into
2305 * schedule() atomically, we ignore that path for now.
2306 * Otherwise, whine if we are scheduling when we should not be.
2308 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
2309 __schedule_bug(prev
);
2312 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2314 schedstat_inc(this_rq(), sched_count
);
2317 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
2319 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
2320 update_rq_clock(rq
);
2321 prev
->sched_class
->put_prev_task(rq
, prev
);
2325 * Pick up the highest-prio task:
2327 static inline struct task_struct
*
2328 pick_next_task(struct rq
*rq
)
2330 const struct sched_class
*class;
2331 struct task_struct
*p
;
2334 * Optimization: we know that if all tasks are in
2335 * the fair class we can call that function directly:
2337 if (likely(rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2338 p
= fair_sched_class
.pick_next_task(rq
);
2343 for_each_class(class) {
2344 p
= class->pick_next_task(rq
);
2349 BUG(); /* the idle class will always have a runnable task */
2353 * __schedule() is the main scheduler function.
2355 * The main means of driving the scheduler and thus entering this function are:
2357 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2359 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2360 * paths. For example, see arch/x86/entry_64.S.
2362 * To drive preemption between tasks, the scheduler sets the flag in timer
2363 * interrupt handler scheduler_tick().
2365 * 3. Wakeups don't really cause entry into schedule(). They add a
2366 * task to the run-queue and that's it.
2368 * Now, if the new task added to the run-queue preempts the current
2369 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2370 * called on the nearest possible occasion:
2372 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2374 * - in syscall or exception context, at the next outmost
2375 * preempt_enable(). (this might be as soon as the wake_up()'s
2378 * - in IRQ context, return from interrupt-handler to
2379 * preemptible context
2381 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2384 * - cond_resched() call
2385 * - explicit schedule() call
2386 * - return from syscall or exception to user-space
2387 * - return from interrupt-handler to user-space
2389 static void __sched
__schedule(void)
2391 struct task_struct
*prev
, *next
;
2392 unsigned long *switch_count
;
2398 cpu
= smp_processor_id();
2400 rcu_note_context_switch(cpu
);
2403 schedule_debug(prev
);
2405 if (sched_feat(HRTICK
))
2409 * Make sure that signal_pending_state()->signal_pending() below
2410 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2411 * done by the caller to avoid the race with signal_wake_up().
2413 smp_mb__before_spinlock();
2414 raw_spin_lock_irq(&rq
->lock
);
2416 switch_count
= &prev
->nivcsw
;
2417 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2418 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2419 prev
->state
= TASK_RUNNING
;
2421 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2425 * If a worker went to sleep, notify and ask workqueue
2426 * whether it wants to wake up a task to maintain
2429 if (prev
->flags
& PF_WQ_WORKER
) {
2430 struct task_struct
*to_wakeup
;
2432 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2434 try_to_wake_up_local(to_wakeup
);
2437 switch_count
= &prev
->nvcsw
;
2440 pre_schedule(rq
, prev
);
2442 if (unlikely(!rq
->nr_running
))
2443 idle_balance(cpu
, rq
);
2445 put_prev_task(rq
, prev
);
2446 next
= pick_next_task(rq
);
2447 clear_tsk_need_resched(prev
);
2448 rq
->skip_clock_update
= 0;
2450 if (likely(prev
!= next
)) {
2455 context_switch(rq
, prev
, next
); /* unlocks the rq */
2457 * The context switch have flipped the stack from under us
2458 * and restored the local variables which were saved when
2459 * this task called schedule() in the past. prev == current
2460 * is still correct, but it can be moved to another cpu/rq.
2462 cpu
= smp_processor_id();
2465 raw_spin_unlock_irq(&rq
->lock
);
2469 sched_preempt_enable_no_resched();
2474 static inline void sched_submit_work(struct task_struct
*tsk
)
2476 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2479 * If we are going to sleep and we have plugged IO queued,
2480 * make sure to submit it to avoid deadlocks.
2482 if (blk_needs_flush_plug(tsk
))
2483 blk_schedule_flush_plug(tsk
);
2486 asmlinkage
void __sched
schedule(void)
2488 struct task_struct
*tsk
= current
;
2490 sched_submit_work(tsk
);
2493 EXPORT_SYMBOL(schedule
);
2495 #ifdef CONFIG_CONTEXT_TRACKING
2496 asmlinkage
void __sched
schedule_user(void)
2499 * If we come here after a random call to set_need_resched(),
2500 * or we have been woken up remotely but the IPI has not yet arrived,
2501 * we haven't yet exited the RCU idle mode. Do it here manually until
2502 * we find a better solution.
2511 * schedule_preempt_disabled - called with preemption disabled
2513 * Returns with preemption disabled. Note: preempt_count must be 1
2515 void __sched
schedule_preempt_disabled(void)
2517 sched_preempt_enable_no_resched();
2522 #ifdef CONFIG_PREEMPT
2524 * this is the entry point to schedule() from in-kernel preemption
2525 * off of preempt_enable. Kernel preemptions off return from interrupt
2526 * occur there and call schedule directly.
2528 asmlinkage
void __sched notrace
preempt_schedule(void)
2530 struct thread_info
*ti
= current_thread_info();
2533 * If there is a non-zero preempt_count or interrupts are disabled,
2534 * we do not want to preempt the current task. Just return..
2536 if (likely(ti
->preempt_count
|| irqs_disabled()))
2540 add_preempt_count_notrace(PREEMPT_ACTIVE
);
2542 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
2545 * Check again in case we missed a preemption opportunity
2546 * between schedule and now.
2549 } while (need_resched());
2551 EXPORT_SYMBOL(preempt_schedule
);
2554 * this is the entry point to schedule() from kernel preemption
2555 * off of irq context.
2556 * Note, that this is called and return with irqs disabled. This will
2557 * protect us against recursive calling from irq.
2559 asmlinkage
void __sched
preempt_schedule_irq(void)
2561 struct thread_info
*ti
= current_thread_info();
2562 enum ctx_state prev_state
;
2564 /* Catch callers which need to be fixed */
2565 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
2567 prev_state
= exception_enter();
2570 add_preempt_count(PREEMPT_ACTIVE
);
2573 local_irq_disable();
2574 sub_preempt_count(PREEMPT_ACTIVE
);
2577 * Check again in case we missed a preemption opportunity
2578 * between schedule and now.
2581 } while (need_resched());
2583 exception_exit(prev_state
);
2586 #endif /* CONFIG_PREEMPT */
2588 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2591 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2593 EXPORT_SYMBOL(default_wake_function
);
2596 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
2597 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
2598 * number) then we wake all the non-exclusive tasks and one exclusive task.
2600 * There are circumstances in which we can try to wake a task which has already
2601 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
2602 * zero in this (rare) case, and we handle it by continuing to scan the queue.
2604 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
2605 int nr_exclusive
, int wake_flags
, void *key
)
2607 wait_queue_t
*curr
, *next
;
2609 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
2610 unsigned flags
= curr
->flags
;
2612 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
2613 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
2619 * __wake_up - wake up threads blocked on a waitqueue.
2621 * @mode: which threads
2622 * @nr_exclusive: how many wake-one or wake-many threads to wake up
2623 * @key: is directly passed to the wakeup function
2625 * It may be assumed that this function implies a write memory barrier before
2626 * changing the task state if and only if any tasks are woken up.
2628 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
2629 int nr_exclusive
, void *key
)
2631 unsigned long flags
;
2633 spin_lock_irqsave(&q
->lock
, flags
);
2634 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
2635 spin_unlock_irqrestore(&q
->lock
, flags
);
2637 EXPORT_SYMBOL(__wake_up
);
2640 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
2642 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
, int nr
)
2644 __wake_up_common(q
, mode
, nr
, 0, NULL
);
2646 EXPORT_SYMBOL_GPL(__wake_up_locked
);
2648 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
2650 __wake_up_common(q
, mode
, 1, 0, key
);
2652 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
2655 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
2657 * @mode: which threads
2658 * @nr_exclusive: how many wake-one or wake-many threads to wake up
2659 * @key: opaque value to be passed to wakeup targets
2661 * The sync wakeup differs that the waker knows that it will schedule
2662 * away soon, so while the target thread will be woken up, it will not
2663 * be migrated to another CPU - ie. the two threads are 'synchronized'
2664 * with each other. This can prevent needless bouncing between CPUs.
2666 * On UP it can prevent extra preemption.
2668 * It may be assumed that this function implies a write memory barrier before
2669 * changing the task state if and only if any tasks are woken up.
2671 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
2672 int nr_exclusive
, void *key
)
2674 unsigned long flags
;
2675 int wake_flags
= WF_SYNC
;
2680 if (unlikely(!nr_exclusive
))
2683 spin_lock_irqsave(&q
->lock
, flags
);
2684 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
2685 spin_unlock_irqrestore(&q
->lock
, flags
);
2687 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
2690 * __wake_up_sync - see __wake_up_sync_key()
2692 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
2694 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
2696 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
2699 * complete: - signals a single thread waiting on this completion
2700 * @x: holds the state of this particular completion
2702 * This will wake up a single thread waiting on this completion. Threads will be
2703 * awakened in the same order in which they were queued.
2705 * See also complete_all(), wait_for_completion() and related routines.
2707 * It may be assumed that this function implies a write memory barrier before
2708 * changing the task state if and only if any tasks are woken up.
2710 void complete(struct completion
*x
)
2712 unsigned long flags
;
2714 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2716 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
2717 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2719 EXPORT_SYMBOL(complete
);
2722 * complete_all: - signals all threads waiting on this completion
2723 * @x: holds the state of this particular completion
2725 * This will wake up all threads waiting on this particular completion event.
2727 * It may be assumed that this function implies a write memory barrier before
2728 * changing the task state if and only if any tasks are woken up.
2730 void complete_all(struct completion
*x
)
2732 unsigned long flags
;
2734 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2735 x
->done
+= UINT_MAX
/2;
2736 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
2737 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2739 EXPORT_SYMBOL(complete_all
);
2741 static inline long __sched
2742 do_wait_for_common(struct completion
*x
,
2743 long (*action
)(long), long timeout
, int state
)
2746 DECLARE_WAITQUEUE(wait
, current
);
2748 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
2750 if (signal_pending_state(state
, current
)) {
2751 timeout
= -ERESTARTSYS
;
2754 __set_current_state(state
);
2755 spin_unlock_irq(&x
->wait
.lock
);
2756 timeout
= action(timeout
);
2757 spin_lock_irq(&x
->wait
.lock
);
2758 } while (!x
->done
&& timeout
);
2759 __remove_wait_queue(&x
->wait
, &wait
);
2764 return timeout
?: 1;
2767 static inline long __sched
2768 __wait_for_common(struct completion
*x
,
2769 long (*action
)(long), long timeout
, int state
)
2773 spin_lock_irq(&x
->wait
.lock
);
2774 timeout
= do_wait_for_common(x
, action
, timeout
, state
);
2775 spin_unlock_irq(&x
->wait
.lock
);
2780 wait_for_common(struct completion
*x
, long timeout
, int state
)
2782 return __wait_for_common(x
, schedule_timeout
, timeout
, state
);
2786 wait_for_common_io(struct completion
*x
, long timeout
, int state
)
2788 return __wait_for_common(x
, io_schedule_timeout
, timeout
, state
);
2792 * wait_for_completion: - waits for completion of a task
2793 * @x: holds the state of this particular completion
2795 * This waits to be signaled for completion of a specific task. It is NOT
2796 * interruptible and there is no timeout.
2798 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
2799 * and interrupt capability. Also see complete().
2801 void __sched
wait_for_completion(struct completion
*x
)
2803 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
2805 EXPORT_SYMBOL(wait_for_completion
);
2808 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
2809 * @x: holds the state of this particular completion
2810 * @timeout: timeout value in jiffies
2812 * This waits for either a completion of a specific task to be signaled or for a
2813 * specified timeout to expire. The timeout is in jiffies. It is not
2816 * Return: 0 if timed out, and positive (at least 1, or number of jiffies left
2817 * till timeout) if completed.
2819 unsigned long __sched
2820 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
2822 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
2824 EXPORT_SYMBOL(wait_for_completion_timeout
);
2827 * wait_for_completion_io: - waits for completion of a task
2828 * @x: holds the state of this particular completion
2830 * This waits to be signaled for completion of a specific task. It is NOT
2831 * interruptible and there is no timeout. The caller is accounted as waiting
2834 void __sched
wait_for_completion_io(struct completion
*x
)
2836 wait_for_common_io(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
2838 EXPORT_SYMBOL(wait_for_completion_io
);
2841 * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout)
2842 * @x: holds the state of this particular completion
2843 * @timeout: timeout value in jiffies
2845 * This waits for either a completion of a specific task to be signaled or for a
2846 * specified timeout to expire. The timeout is in jiffies. It is not
2847 * interruptible. The caller is accounted as waiting for IO.
2849 * Return: 0 if timed out, and positive (at least 1, or number of jiffies left
2850 * till timeout) if completed.
2852 unsigned long __sched
2853 wait_for_completion_io_timeout(struct completion
*x
, unsigned long timeout
)
2855 return wait_for_common_io(x
, timeout
, TASK_UNINTERRUPTIBLE
);
2857 EXPORT_SYMBOL(wait_for_completion_io_timeout
);
2860 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
2861 * @x: holds the state of this particular completion
2863 * This waits for completion of a specific task to be signaled. It is
2866 * Return: -ERESTARTSYS if interrupted, 0 if completed.
2868 int __sched
wait_for_completion_interruptible(struct completion
*x
)
2870 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
2871 if (t
== -ERESTARTSYS
)
2875 EXPORT_SYMBOL(wait_for_completion_interruptible
);
2878 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
2879 * @x: holds the state of this particular completion
2880 * @timeout: timeout value in jiffies
2882 * This waits for either a completion of a specific task to be signaled or for a
2883 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
2885 * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
2886 * or number of jiffies left till timeout) if completed.
2889 wait_for_completion_interruptible_timeout(struct completion
*x
,
2890 unsigned long timeout
)
2892 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
2894 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
2897 * wait_for_completion_killable: - waits for completion of a task (killable)
2898 * @x: holds the state of this particular completion
2900 * This waits to be signaled for completion of a specific task. It can be
2901 * interrupted by a kill signal.
2903 * Return: -ERESTARTSYS if interrupted, 0 if completed.
2905 int __sched
wait_for_completion_killable(struct completion
*x
)
2907 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
2908 if (t
== -ERESTARTSYS
)
2912 EXPORT_SYMBOL(wait_for_completion_killable
);
2915 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
2916 * @x: holds the state of this particular completion
2917 * @timeout: timeout value in jiffies
2919 * This waits for either a completion of a specific task to be
2920 * signaled or for a specified timeout to expire. It can be
2921 * interrupted by a kill signal. The timeout is in jiffies.
2923 * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1,
2924 * or number of jiffies left till timeout) if completed.
2927 wait_for_completion_killable_timeout(struct completion
*x
,
2928 unsigned long timeout
)
2930 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
2932 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
2935 * try_wait_for_completion - try to decrement a completion without blocking
2936 * @x: completion structure
2938 * Return: 0 if a decrement cannot be done without blocking
2939 * 1 if a decrement succeeded.
2941 * If a completion is being used as a counting completion,
2942 * attempt to decrement the counter without blocking. This
2943 * enables us to avoid waiting if the resource the completion
2944 * is protecting is not available.
2946 bool try_wait_for_completion(struct completion
*x
)
2948 unsigned long flags
;
2951 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2956 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2959 EXPORT_SYMBOL(try_wait_for_completion
);
2962 * completion_done - Test to see if a completion has any waiters
2963 * @x: completion structure
2965 * Return: 0 if there are waiters (wait_for_completion() in progress)
2966 * 1 if there are no waiters.
2969 bool completion_done(struct completion
*x
)
2971 unsigned long flags
;
2974 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2977 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2980 EXPORT_SYMBOL(completion_done
);
2983 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
2985 unsigned long flags
;
2988 init_waitqueue_entry(&wait
, current
);
2990 __set_current_state(state
);
2992 spin_lock_irqsave(&q
->lock
, flags
);
2993 __add_wait_queue(q
, &wait
);
2994 spin_unlock(&q
->lock
);
2995 timeout
= schedule_timeout(timeout
);
2996 spin_lock_irq(&q
->lock
);
2997 __remove_wait_queue(q
, &wait
);
2998 spin_unlock_irqrestore(&q
->lock
, flags
);
3003 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
3005 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3007 EXPORT_SYMBOL(interruptible_sleep_on
);
3010 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3012 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
3014 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
3016 void __sched
sleep_on(wait_queue_head_t
*q
)
3018 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3020 EXPORT_SYMBOL(sleep_on
);
3022 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3024 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
3026 EXPORT_SYMBOL(sleep_on_timeout
);
3028 #ifdef CONFIG_RT_MUTEXES
3031 * rt_mutex_setprio - set the current priority of a task
3033 * @prio: prio value (kernel-internal form)
3035 * This function changes the 'effective' priority of a task. It does
3036 * not touch ->normal_prio like __setscheduler().
3038 * Used by the rt_mutex code to implement priority inheritance logic.
3040 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
3042 int oldprio
, on_rq
, running
;
3044 const struct sched_class
*prev_class
;
3046 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
3048 rq
= __task_rq_lock(p
);
3051 * Idle task boosting is a nono in general. There is one
3052 * exception, when PREEMPT_RT and NOHZ is active:
3054 * The idle task calls get_next_timer_interrupt() and holds
3055 * the timer wheel base->lock on the CPU and another CPU wants
3056 * to access the timer (probably to cancel it). We can safely
3057 * ignore the boosting request, as the idle CPU runs this code
3058 * with interrupts disabled and will complete the lock
3059 * protected section without being interrupted. So there is no
3060 * real need to boost.
3062 if (unlikely(p
== rq
->idle
)) {
3063 WARN_ON(p
!= rq
->curr
);
3064 WARN_ON(p
->pi_blocked_on
);
3068 trace_sched_pi_setprio(p
, prio
);
3070 prev_class
= p
->sched_class
;
3072 running
= task_current(rq
, p
);
3074 dequeue_task(rq
, p
, 0);
3076 p
->sched_class
->put_prev_task(rq
, p
);
3079 p
->sched_class
= &rt_sched_class
;
3081 p
->sched_class
= &fair_sched_class
;
3086 p
->sched_class
->set_curr_task(rq
);
3088 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
3090 check_class_changed(rq
, p
, prev_class
, oldprio
);
3092 __task_rq_unlock(rq
);
3095 void set_user_nice(struct task_struct
*p
, long nice
)
3097 int old_prio
, delta
, on_rq
;
3098 unsigned long flags
;
3101 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
3104 * We have to be careful, if called from sys_setpriority(),
3105 * the task might be in the middle of scheduling on another CPU.
3107 rq
= task_rq_lock(p
, &flags
);
3109 * The RT priorities are set via sched_setscheduler(), but we still
3110 * allow the 'normal' nice value to be set - but as expected
3111 * it wont have any effect on scheduling until the task is
3112 * SCHED_FIFO/SCHED_RR:
3114 if (task_has_rt_policy(p
)) {
3115 p
->static_prio
= NICE_TO_PRIO(nice
);
3120 dequeue_task(rq
, p
, 0);
3122 p
->static_prio
= NICE_TO_PRIO(nice
);
3125 p
->prio
= effective_prio(p
);
3126 delta
= p
->prio
- old_prio
;
3129 enqueue_task(rq
, p
, 0);
3131 * If the task increased its priority or is running and
3132 * lowered its priority, then reschedule its CPU:
3134 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3135 resched_task(rq
->curr
);
3138 task_rq_unlock(rq
, p
, &flags
);
3140 EXPORT_SYMBOL(set_user_nice
);
3143 * can_nice - check if a task can reduce its nice value
3147 int can_nice(const struct task_struct
*p
, const int nice
)
3149 /* convert nice value [19,-20] to rlimit style value [1,40] */
3150 int nice_rlim
= 20 - nice
;
3152 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3153 capable(CAP_SYS_NICE
));
3156 #ifdef __ARCH_WANT_SYS_NICE
3159 * sys_nice - change the priority of the current process.
3160 * @increment: priority increment
3162 * sys_setpriority is a more generic, but much slower function that
3163 * does similar things.
3165 SYSCALL_DEFINE1(nice
, int, increment
)
3170 * Setpriority might change our priority at the same moment.
3171 * We don't have to worry. Conceptually one call occurs first
3172 * and we have a single winner.
3174 if (increment
< -40)
3179 nice
= TASK_NICE(current
) + increment
;
3185 if (increment
< 0 && !can_nice(current
, nice
))
3188 retval
= security_task_setnice(current
, nice
);
3192 set_user_nice(current
, nice
);
3199 * task_prio - return the priority value of a given task.
3200 * @p: the task in question.
3202 * Return: The priority value as seen by users in /proc.
3203 * RT tasks are offset by -200. Normal tasks are centered
3204 * around 0, value goes from -16 to +15.
3206 int task_prio(const struct task_struct
*p
)
3208 return p
->prio
- MAX_RT_PRIO
;
3212 * task_nice - return the nice value of a given task.
3213 * @p: the task in question.
3215 * Return: The nice value [ -20 ... 0 ... 19 ].
3217 int task_nice(const struct task_struct
*p
)
3219 return TASK_NICE(p
);
3221 EXPORT_SYMBOL(task_nice
);
3224 * idle_cpu - is a given cpu idle currently?
3225 * @cpu: the processor in question.
3227 * Return: 1 if the CPU is currently idle. 0 otherwise.
3229 int idle_cpu(int cpu
)
3231 struct rq
*rq
= cpu_rq(cpu
);
3233 if (rq
->curr
!= rq
->idle
)
3240 if (!llist_empty(&rq
->wake_list
))
3248 * idle_task - return the idle task for a given cpu.
3249 * @cpu: the processor in question.
3251 * Return: The idle task for the cpu @cpu.
3253 struct task_struct
*idle_task(int cpu
)
3255 return cpu_rq(cpu
)->idle
;
3259 * find_process_by_pid - find a process with a matching PID value.
3260 * @pid: the pid in question.
3262 * The task of @pid, if found. %NULL otherwise.
3264 static struct task_struct
*find_process_by_pid(pid_t pid
)
3266 return pid
? find_task_by_vpid(pid
) : current
;
3269 /* Actually do priority change: must hold rq lock. */
3271 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
3274 p
->rt_priority
= prio
;
3275 p
->normal_prio
= normal_prio(p
);
3276 /* we are holding p->pi_lock already */
3277 p
->prio
= rt_mutex_getprio(p
);
3278 if (rt_prio(p
->prio
))
3279 p
->sched_class
= &rt_sched_class
;
3281 p
->sched_class
= &fair_sched_class
;
3286 * check the target process has a UID that matches the current process's
3288 static bool check_same_owner(struct task_struct
*p
)
3290 const struct cred
*cred
= current_cred(), *pcred
;
3294 pcred
= __task_cred(p
);
3295 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3296 uid_eq(cred
->euid
, pcred
->uid
));
3301 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
3302 const struct sched_param
*param
, bool user
)
3304 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
3305 unsigned long flags
;
3306 const struct sched_class
*prev_class
;
3310 /* may grab non-irq protected spin_locks */
3311 BUG_ON(in_interrupt());
3313 /* double check policy once rq lock held */
3315 reset_on_fork
= p
->sched_reset_on_fork
;
3316 policy
= oldpolicy
= p
->policy
;
3318 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
3319 policy
&= ~SCHED_RESET_ON_FORK
;
3321 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3322 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3323 policy
!= SCHED_IDLE
)
3328 * Valid priorities for SCHED_FIFO and SCHED_RR are
3329 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3330 * SCHED_BATCH and SCHED_IDLE is 0.
3332 if (param
->sched_priority
< 0 ||
3333 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3334 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
3336 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
3340 * Allow unprivileged RT tasks to decrease priority:
3342 if (user
&& !capable(CAP_SYS_NICE
)) {
3343 if (rt_policy(policy
)) {
3344 unsigned long rlim_rtprio
=
3345 task_rlimit(p
, RLIMIT_RTPRIO
);
3347 /* can't set/change the rt policy */
3348 if (policy
!= p
->policy
&& !rlim_rtprio
)
3351 /* can't increase priority */
3352 if (param
->sched_priority
> p
->rt_priority
&&
3353 param
->sched_priority
> rlim_rtprio
)
3358 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3359 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3361 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3362 if (!can_nice(p
, TASK_NICE(p
)))
3366 /* can't change other user's priorities */
3367 if (!check_same_owner(p
))
3370 /* Normal users shall not reset the sched_reset_on_fork flag */
3371 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3376 retval
= security_task_setscheduler(p
);
3382 * make sure no PI-waiters arrive (or leave) while we are
3383 * changing the priority of the task:
3385 * To be able to change p->policy safely, the appropriate
3386 * runqueue lock must be held.
3388 rq
= task_rq_lock(p
, &flags
);
3391 * Changing the policy of the stop threads its a very bad idea
3393 if (p
== rq
->stop
) {
3394 task_rq_unlock(rq
, p
, &flags
);
3399 * If not changing anything there's no need to proceed further:
3401 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
3402 param
->sched_priority
== p
->rt_priority
))) {
3403 task_rq_unlock(rq
, p
, &flags
);
3407 #ifdef CONFIG_RT_GROUP_SCHED
3410 * Do not allow realtime tasks into groups that have no runtime
3413 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3414 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3415 !task_group_is_autogroup(task_group(p
))) {
3416 task_rq_unlock(rq
, p
, &flags
);
3422 /* recheck policy now with rq lock held */
3423 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3424 policy
= oldpolicy
= -1;
3425 task_rq_unlock(rq
, p
, &flags
);
3429 running
= task_current(rq
, p
);
3431 dequeue_task(rq
, p
, 0);
3433 p
->sched_class
->put_prev_task(rq
, p
);
3435 p
->sched_reset_on_fork
= reset_on_fork
;
3438 prev_class
= p
->sched_class
;
3439 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
3442 p
->sched_class
->set_curr_task(rq
);
3444 enqueue_task(rq
, p
, 0);
3446 check_class_changed(rq
, p
, prev_class
, oldprio
);
3447 task_rq_unlock(rq
, p
, &flags
);
3449 rt_mutex_adjust_pi(p
);
3455 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3456 * @p: the task in question.
3457 * @policy: new policy.
3458 * @param: structure containing the new RT priority.
3460 * Return: 0 on success. An error code otherwise.
3462 * NOTE that the task may be already dead.
3464 int sched_setscheduler(struct task_struct
*p
, int policy
,
3465 const struct sched_param
*param
)
3467 return __sched_setscheduler(p
, policy
, param
, true);
3469 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3472 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3473 * @p: the task in question.
3474 * @policy: new policy.
3475 * @param: structure containing the new RT priority.
3477 * Just like sched_setscheduler, only don't bother checking if the
3478 * current context has permission. For example, this is needed in
3479 * stop_machine(): we create temporary high priority worker threads,
3480 * but our caller might not have that capability.
3482 * Return: 0 on success. An error code otherwise.
3484 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3485 const struct sched_param
*param
)
3487 return __sched_setscheduler(p
, policy
, param
, false);
3491 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3493 struct sched_param lparam
;
3494 struct task_struct
*p
;
3497 if (!param
|| pid
< 0)
3499 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3504 p
= find_process_by_pid(pid
);
3506 retval
= sched_setscheduler(p
, policy
, &lparam
);
3513 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3514 * @pid: the pid in question.
3515 * @policy: new policy.
3516 * @param: structure containing the new RT priority.
3518 * Return: 0 on success. An error code otherwise.
3520 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3521 struct sched_param __user
*, param
)
3523 /* negative values for policy are not valid */
3527 return do_sched_setscheduler(pid
, policy
, param
);
3531 * sys_sched_setparam - set/change the RT priority of a thread
3532 * @pid: the pid in question.
3533 * @param: structure containing the new RT priority.
3535 * Return: 0 on success. An error code otherwise.
3537 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3539 return do_sched_setscheduler(pid
, -1, param
);
3543 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3544 * @pid: the pid in question.
3546 * Return: On success, the policy of the thread. Otherwise, a negative error
3549 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3551 struct task_struct
*p
;
3559 p
= find_process_by_pid(pid
);
3561 retval
= security_task_getscheduler(p
);
3564 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3571 * sys_sched_getparam - get the RT priority of a thread
3572 * @pid: the pid in question.
3573 * @param: structure containing the RT priority.
3575 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3578 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3580 struct sched_param lp
;
3581 struct task_struct
*p
;
3584 if (!param
|| pid
< 0)
3588 p
= find_process_by_pid(pid
);
3593 retval
= security_task_getscheduler(p
);
3597 lp
.sched_priority
= p
->rt_priority
;
3601 * This one might sleep, we cannot do it with a spinlock held ...
3603 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3612 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
3614 cpumask_var_t cpus_allowed
, new_mask
;
3615 struct task_struct
*p
;
3621 p
= find_process_by_pid(pid
);
3628 /* Prevent p going away */
3632 if (p
->flags
& PF_NO_SETAFFINITY
) {
3636 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
3640 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
3642 goto out_free_cpus_allowed
;
3645 if (!check_same_owner(p
)) {
3647 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
3654 retval
= security_task_setscheduler(p
);
3658 cpuset_cpus_allowed(p
, cpus_allowed
);
3659 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
3661 retval
= set_cpus_allowed_ptr(p
, new_mask
);
3664 cpuset_cpus_allowed(p
, cpus_allowed
);
3665 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
3667 * We must have raced with a concurrent cpuset
3668 * update. Just reset the cpus_allowed to the
3669 * cpuset's cpus_allowed
3671 cpumask_copy(new_mask
, cpus_allowed
);
3676 free_cpumask_var(new_mask
);
3677 out_free_cpus_allowed
:
3678 free_cpumask_var(cpus_allowed
);
3685 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
3686 struct cpumask
*new_mask
)
3688 if (len
< cpumask_size())
3689 cpumask_clear(new_mask
);
3690 else if (len
> cpumask_size())
3691 len
= cpumask_size();
3693 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
3697 * sys_sched_setaffinity - set the cpu affinity of a process
3698 * @pid: pid of the process
3699 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3700 * @user_mask_ptr: user-space pointer to the new cpu mask
3702 * Return: 0 on success. An error code otherwise.
3704 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
3705 unsigned long __user
*, user_mask_ptr
)
3707 cpumask_var_t new_mask
;
3710 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
3713 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
3715 retval
= sched_setaffinity(pid
, new_mask
);
3716 free_cpumask_var(new_mask
);
3720 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
3722 struct task_struct
*p
;
3723 unsigned long flags
;
3730 p
= find_process_by_pid(pid
);
3734 retval
= security_task_getscheduler(p
);
3738 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
3739 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
3740 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
3750 * sys_sched_getaffinity - get the cpu affinity of a process
3751 * @pid: pid of the process
3752 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3753 * @user_mask_ptr: user-space pointer to hold the current cpu mask
3755 * Return: 0 on success. An error code otherwise.
3757 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
3758 unsigned long __user
*, user_mask_ptr
)
3763 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
3765 if (len
& (sizeof(unsigned long)-1))
3768 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
3771 ret
= sched_getaffinity(pid
, mask
);
3773 size_t retlen
= min_t(size_t, len
, cpumask_size());
3775 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
3780 free_cpumask_var(mask
);
3786 * sys_sched_yield - yield the current processor to other threads.
3788 * This function yields the current CPU to other tasks. If there are no
3789 * other threads running on this CPU then this function will return.
3793 SYSCALL_DEFINE0(sched_yield
)
3795 struct rq
*rq
= this_rq_lock();
3797 schedstat_inc(rq
, yld_count
);
3798 current
->sched_class
->yield_task(rq
);
3801 * Since we are going to call schedule() anyway, there's
3802 * no need to preempt or enable interrupts:
3804 __release(rq
->lock
);
3805 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
3806 do_raw_spin_unlock(&rq
->lock
);
3807 sched_preempt_enable_no_resched();
3814 static inline int should_resched(void)
3816 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
3819 static void __cond_resched(void)
3821 add_preempt_count(PREEMPT_ACTIVE
);
3823 sub_preempt_count(PREEMPT_ACTIVE
);
3826 int __sched
_cond_resched(void)
3828 if (should_resched()) {
3834 EXPORT_SYMBOL(_cond_resched
);
3837 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
3838 * call schedule, and on return reacquire the lock.
3840 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
3841 * operations here to prevent schedule() from being called twice (once via
3842 * spin_unlock(), once by hand).
3844 int __cond_resched_lock(spinlock_t
*lock
)
3846 int resched
= should_resched();
3849 lockdep_assert_held(lock
);
3851 if (spin_needbreak(lock
) || resched
) {
3862 EXPORT_SYMBOL(__cond_resched_lock
);
3864 int __sched
__cond_resched_softirq(void)
3866 BUG_ON(!in_softirq());
3868 if (should_resched()) {
3876 EXPORT_SYMBOL(__cond_resched_softirq
);
3879 * yield - yield the current processor to other threads.
3881 * Do not ever use this function, there's a 99% chance you're doing it wrong.
3883 * The scheduler is at all times free to pick the calling task as the most
3884 * eligible task to run, if removing the yield() call from your code breaks
3885 * it, its already broken.
3887 * Typical broken usage is:
3892 * where one assumes that yield() will let 'the other' process run that will
3893 * make event true. If the current task is a SCHED_FIFO task that will never
3894 * happen. Never use yield() as a progress guarantee!!
3896 * If you want to use yield() to wait for something, use wait_event().
3897 * If you want to use yield() to be 'nice' for others, use cond_resched().
3898 * If you still want to use yield(), do not!
3900 void __sched
yield(void)
3902 set_current_state(TASK_RUNNING
);
3905 EXPORT_SYMBOL(yield
);
3908 * yield_to - yield the current processor to another thread in
3909 * your thread group, or accelerate that thread toward the
3910 * processor it's on.
3912 * @preempt: whether task preemption is allowed or not
3914 * It's the caller's job to ensure that the target task struct
3915 * can't go away on us before we can do any checks.
3918 * true (>0) if we indeed boosted the target task.
3919 * false (0) if we failed to boost the target.
3920 * -ESRCH if there's no task to yield to.
3922 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
3924 struct task_struct
*curr
= current
;
3925 struct rq
*rq
, *p_rq
;
3926 unsigned long flags
;
3929 local_irq_save(flags
);
3935 * If we're the only runnable task on the rq and target rq also
3936 * has only one task, there's absolutely no point in yielding.
3938 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
3943 double_rq_lock(rq
, p_rq
);
3944 while (task_rq(p
) != p_rq
) {
3945 double_rq_unlock(rq
, p_rq
);
3949 if (!curr
->sched_class
->yield_to_task
)
3952 if (curr
->sched_class
!= p
->sched_class
)
3955 if (task_running(p_rq
, p
) || p
->state
)
3958 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
3960 schedstat_inc(rq
, yld_count
);
3962 * Make p's CPU reschedule; pick_next_entity takes care of
3965 if (preempt
&& rq
!= p_rq
)
3966 resched_task(p_rq
->curr
);
3970 double_rq_unlock(rq
, p_rq
);
3972 local_irq_restore(flags
);
3979 EXPORT_SYMBOL_GPL(yield_to
);
3982 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
3983 * that process accounting knows that this is a task in IO wait state.
3985 void __sched
io_schedule(void)
3987 struct rq
*rq
= raw_rq();
3989 delayacct_blkio_start();
3990 atomic_inc(&rq
->nr_iowait
);
3991 blk_flush_plug(current
);
3992 current
->in_iowait
= 1;
3994 current
->in_iowait
= 0;
3995 atomic_dec(&rq
->nr_iowait
);
3996 delayacct_blkio_end();
3998 EXPORT_SYMBOL(io_schedule
);
4000 long __sched
io_schedule_timeout(long timeout
)
4002 struct rq
*rq
= raw_rq();
4005 delayacct_blkio_start();
4006 atomic_inc(&rq
->nr_iowait
);
4007 blk_flush_plug(current
);
4008 current
->in_iowait
= 1;
4009 ret
= schedule_timeout(timeout
);
4010 current
->in_iowait
= 0;
4011 atomic_dec(&rq
->nr_iowait
);
4012 delayacct_blkio_end();
4017 * sys_sched_get_priority_max - return maximum RT priority.
4018 * @policy: scheduling class.
4020 * Return: On success, this syscall returns the maximum
4021 * rt_priority that can be used by a given scheduling class.
4022 * On failure, a negative error code is returned.
4024 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4031 ret
= MAX_USER_RT_PRIO
-1;
4043 * sys_sched_get_priority_min - return minimum RT priority.
4044 * @policy: scheduling class.
4046 * Return: On success, this syscall returns the minimum
4047 * rt_priority that can be used by a given scheduling class.
4048 * On failure, a negative error code is returned.
4050 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4068 * sys_sched_rr_get_interval - return the default timeslice of a process.
4069 * @pid: pid of the process.
4070 * @interval: userspace pointer to the timeslice value.
4072 * this syscall writes the default timeslice value of a given process
4073 * into the user-space timespec buffer. A value of '0' means infinity.
4075 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4078 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4079 struct timespec __user
*, interval
)
4081 struct task_struct
*p
;
4082 unsigned int time_slice
;
4083 unsigned long flags
;
4093 p
= find_process_by_pid(pid
);
4097 retval
= security_task_getscheduler(p
);
4101 rq
= task_rq_lock(p
, &flags
);
4102 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4103 task_rq_unlock(rq
, p
, &flags
);
4106 jiffies_to_timespec(time_slice
, &t
);
4107 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4115 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4117 void sched_show_task(struct task_struct
*p
)
4119 unsigned long free
= 0;
4123 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4124 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4125 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4126 #if BITS_PER_LONG == 32
4127 if (state
== TASK_RUNNING
)
4128 printk(KERN_CONT
" running ");
4130 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4132 if (state
== TASK_RUNNING
)
4133 printk(KERN_CONT
" running task ");
4135 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4137 #ifdef CONFIG_DEBUG_STACK_USAGE
4138 free
= stack_not_used(p
);
4141 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4143 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4144 task_pid_nr(p
), ppid
,
4145 (unsigned long)task_thread_info(p
)->flags
);
4147 print_worker_info(KERN_INFO
, p
);
4148 show_stack(p
, NULL
);
4151 void show_state_filter(unsigned long state_filter
)
4153 struct task_struct
*g
, *p
;
4155 #if BITS_PER_LONG == 32
4157 " task PC stack pid father\n");
4160 " task PC stack pid father\n");
4163 do_each_thread(g
, p
) {
4165 * reset the NMI-timeout, listing all files on a slow
4166 * console might take a lot of time:
4168 touch_nmi_watchdog();
4169 if (!state_filter
|| (p
->state
& state_filter
))
4171 } while_each_thread(g
, p
);
4173 touch_all_softlockup_watchdogs();
4175 #ifdef CONFIG_SCHED_DEBUG
4176 sysrq_sched_debug_show();
4180 * Only show locks if all tasks are dumped:
4183 debug_show_all_locks();
4186 void init_idle_bootup_task(struct task_struct
*idle
)
4188 idle
->sched_class
= &idle_sched_class
;
4192 * init_idle - set up an idle thread for a given CPU
4193 * @idle: task in question
4194 * @cpu: cpu the idle task belongs to
4196 * NOTE: this function does not set the idle thread's NEED_RESCHED
4197 * flag, to make booting more robust.
4199 void init_idle(struct task_struct
*idle
, int cpu
)
4201 struct rq
*rq
= cpu_rq(cpu
);
4202 unsigned long flags
;
4204 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4207 idle
->state
= TASK_RUNNING
;
4208 idle
->se
.exec_start
= sched_clock();
4210 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4212 * We're having a chicken and egg problem, even though we are
4213 * holding rq->lock, the cpu isn't yet set to this cpu so the
4214 * lockdep check in task_group() will fail.
4216 * Similar case to sched_fork(). / Alternatively we could
4217 * use task_rq_lock() here and obtain the other rq->lock.
4222 __set_task_cpu(idle
, cpu
);
4225 rq
->curr
= rq
->idle
= idle
;
4226 #if defined(CONFIG_SMP)
4229 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4231 /* Set the preempt count _outside_ the spinlocks! */
4232 task_thread_info(idle
)->preempt_count
= 0;
4235 * The idle tasks have their own, simple scheduling class:
4237 idle
->sched_class
= &idle_sched_class
;
4238 ftrace_graph_init_idle_task(idle
, cpu
);
4239 vtime_init_idle(idle
, cpu
);
4240 #if defined(CONFIG_SMP)
4241 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4246 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4248 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4249 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4251 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4252 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4256 * This is how migration works:
4258 * 1) we invoke migration_cpu_stop() on the target CPU using
4260 * 2) stopper starts to run (implicitly forcing the migrated thread
4262 * 3) it checks whether the migrated task is still in the wrong runqueue.
4263 * 4) if it's in the wrong runqueue then the migration thread removes
4264 * it and puts it into the right queue.
4265 * 5) stopper completes and stop_one_cpu() returns and the migration
4270 * Change a given task's CPU affinity. Migrate the thread to a
4271 * proper CPU and schedule it away if the CPU it's executing on
4272 * is removed from the allowed bitmask.
4274 * NOTE: the caller must have a valid reference to the task, the
4275 * task must not exit() & deallocate itself prematurely. The
4276 * call is not atomic; no spinlocks may be held.
4278 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4280 unsigned long flags
;
4282 unsigned int dest_cpu
;
4285 rq
= task_rq_lock(p
, &flags
);
4287 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4290 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4295 do_set_cpus_allowed(p
, new_mask
);
4297 /* Can the task run on the task's current CPU? If so, we're done */
4298 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4301 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4303 struct migration_arg arg
= { p
, dest_cpu
};
4304 /* Need help from migration thread: drop lock and wait. */
4305 task_rq_unlock(rq
, p
, &flags
);
4306 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4307 tlb_migrate_finish(p
->mm
);
4311 task_rq_unlock(rq
, p
, &flags
);
4315 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4318 * Move (not current) task off this cpu, onto dest cpu. We're doing
4319 * this because either it can't run here any more (set_cpus_allowed()
4320 * away from this CPU, or CPU going down), or because we're
4321 * attempting to rebalance this task on exec (sched_exec).
4323 * So we race with normal scheduler movements, but that's OK, as long
4324 * as the task is no longer on this CPU.
4326 * Returns non-zero if task was successfully migrated.
4328 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4330 struct rq
*rq_dest
, *rq_src
;
4333 if (unlikely(!cpu_active(dest_cpu
)))
4336 rq_src
= cpu_rq(src_cpu
);
4337 rq_dest
= cpu_rq(dest_cpu
);
4339 raw_spin_lock(&p
->pi_lock
);
4340 double_rq_lock(rq_src
, rq_dest
);
4341 /* Already moved. */
4342 if (task_cpu(p
) != src_cpu
)
4344 /* Affinity changed (again). */
4345 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4349 * If we're not on a rq, the next wake-up will ensure we're
4353 dequeue_task(rq_src
, p
, 0);
4354 set_task_cpu(p
, dest_cpu
);
4355 enqueue_task(rq_dest
, p
, 0);
4356 check_preempt_curr(rq_dest
, p
, 0);
4361 double_rq_unlock(rq_src
, rq_dest
);
4362 raw_spin_unlock(&p
->pi_lock
);
4367 * migration_cpu_stop - this will be executed by a highprio stopper thread
4368 * and performs thread migration by bumping thread off CPU then
4369 * 'pushing' onto another runqueue.
4371 static int migration_cpu_stop(void *data
)
4373 struct migration_arg
*arg
= data
;
4376 * The original target cpu might have gone down and we might
4377 * be on another cpu but it doesn't matter.
4379 local_irq_disable();
4380 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4385 #ifdef CONFIG_HOTPLUG_CPU
4388 * Ensures that the idle task is using init_mm right before its cpu goes
4391 void idle_task_exit(void)
4393 struct mm_struct
*mm
= current
->active_mm
;
4395 BUG_ON(cpu_online(smp_processor_id()));
4398 switch_mm(mm
, &init_mm
, current
);
4403 * Since this CPU is going 'away' for a while, fold any nr_active delta
4404 * we might have. Assumes we're called after migrate_tasks() so that the
4405 * nr_active count is stable.
4407 * Also see the comment "Global load-average calculations".
4409 static void calc_load_migrate(struct rq
*rq
)
4411 long delta
= calc_load_fold_active(rq
);
4413 atomic_long_add(delta
, &calc_load_tasks
);
4417 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4418 * try_to_wake_up()->select_task_rq().
4420 * Called with rq->lock held even though we'er in stop_machine() and
4421 * there's no concurrency possible, we hold the required locks anyway
4422 * because of lock validation efforts.
4424 static void migrate_tasks(unsigned int dead_cpu
)
4426 struct rq
*rq
= cpu_rq(dead_cpu
);
4427 struct task_struct
*next
, *stop
= rq
->stop
;
4431 * Fudge the rq selection such that the below task selection loop
4432 * doesn't get stuck on the currently eligible stop task.
4434 * We're currently inside stop_machine() and the rq is either stuck
4435 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4436 * either way we should never end up calling schedule() until we're
4442 * put_prev_task() and pick_next_task() sched
4443 * class method both need to have an up-to-date
4444 * value of rq->clock[_task]
4446 update_rq_clock(rq
);
4450 * There's this thread running, bail when that's the only
4453 if (rq
->nr_running
== 1)
4456 next
= pick_next_task(rq
);
4458 next
->sched_class
->put_prev_task(rq
, next
);
4460 /* Find suitable destination for @next, with force if needed. */
4461 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
4462 raw_spin_unlock(&rq
->lock
);
4464 __migrate_task(next
, dead_cpu
, dest_cpu
);
4466 raw_spin_lock(&rq
->lock
);
4472 #endif /* CONFIG_HOTPLUG_CPU */
4474 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4476 static struct ctl_table sd_ctl_dir
[] = {
4478 .procname
= "sched_domain",
4484 static struct ctl_table sd_ctl_root
[] = {
4486 .procname
= "kernel",
4488 .child
= sd_ctl_dir
,
4493 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
4495 struct ctl_table
*entry
=
4496 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
4501 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
4503 struct ctl_table
*entry
;
4506 * In the intermediate directories, both the child directory and
4507 * procname are dynamically allocated and could fail but the mode
4508 * will always be set. In the lowest directory the names are
4509 * static strings and all have proc handlers.
4511 for (entry
= *tablep
; entry
->mode
; entry
++) {
4513 sd_free_ctl_entry(&entry
->child
);
4514 if (entry
->proc_handler
== NULL
)
4515 kfree(entry
->procname
);
4522 static int min_load_idx
= 0;
4523 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
4526 set_table_entry(struct ctl_table
*entry
,
4527 const char *procname
, void *data
, int maxlen
,
4528 umode_t mode
, proc_handler
*proc_handler
,
4531 entry
->procname
= procname
;
4533 entry
->maxlen
= maxlen
;
4535 entry
->proc_handler
= proc_handler
;
4538 entry
->extra1
= &min_load_idx
;
4539 entry
->extra2
= &max_load_idx
;
4543 static struct ctl_table
*
4544 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
4546 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
4551 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
4552 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4553 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
4554 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4555 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
4556 sizeof(int), 0644, proc_dointvec_minmax
, true);
4557 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
4558 sizeof(int), 0644, proc_dointvec_minmax
, true);
4559 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
4560 sizeof(int), 0644, proc_dointvec_minmax
, true);
4561 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
4562 sizeof(int), 0644, proc_dointvec_minmax
, true);
4563 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
4564 sizeof(int), 0644, proc_dointvec_minmax
, true);
4565 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
4566 sizeof(int), 0644, proc_dointvec_minmax
, false);
4567 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
4568 sizeof(int), 0644, proc_dointvec_minmax
, false);
4569 set_table_entry(&table
[9], "cache_nice_tries",
4570 &sd
->cache_nice_tries
,
4571 sizeof(int), 0644, proc_dointvec_minmax
, false);
4572 set_table_entry(&table
[10], "flags", &sd
->flags
,
4573 sizeof(int), 0644, proc_dointvec_minmax
, false);
4574 set_table_entry(&table
[11], "name", sd
->name
,
4575 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
4576 /* &table[12] is terminator */
4581 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
4583 struct ctl_table
*entry
, *table
;
4584 struct sched_domain
*sd
;
4585 int domain_num
= 0, i
;
4588 for_each_domain(cpu
, sd
)
4590 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
4595 for_each_domain(cpu
, sd
) {
4596 snprintf(buf
, 32, "domain%d", i
);
4597 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4599 entry
->child
= sd_alloc_ctl_domain_table(sd
);
4606 static struct ctl_table_header
*sd_sysctl_header
;
4607 static void register_sched_domain_sysctl(void)
4609 int i
, cpu_num
= num_possible_cpus();
4610 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
4613 WARN_ON(sd_ctl_dir
[0].child
);
4614 sd_ctl_dir
[0].child
= entry
;
4619 for_each_possible_cpu(i
) {
4620 snprintf(buf
, 32, "cpu%d", i
);
4621 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4623 entry
->child
= sd_alloc_ctl_cpu_table(i
);
4627 WARN_ON(sd_sysctl_header
);
4628 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
4631 /* may be called multiple times per register */
4632 static void unregister_sched_domain_sysctl(void)
4634 if (sd_sysctl_header
)
4635 unregister_sysctl_table(sd_sysctl_header
);
4636 sd_sysctl_header
= NULL
;
4637 if (sd_ctl_dir
[0].child
)
4638 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
4641 static void register_sched_domain_sysctl(void)
4644 static void unregister_sched_domain_sysctl(void)
4649 static void set_rq_online(struct rq
*rq
)
4652 const struct sched_class
*class;
4654 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
4657 for_each_class(class) {
4658 if (class->rq_online
)
4659 class->rq_online(rq
);
4664 static void set_rq_offline(struct rq
*rq
)
4667 const struct sched_class
*class;
4669 for_each_class(class) {
4670 if (class->rq_offline
)
4671 class->rq_offline(rq
);
4674 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
4680 * migration_call - callback that gets triggered when a CPU is added.
4681 * Here we can start up the necessary migration thread for the new CPU.
4684 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
4686 int cpu
= (long)hcpu
;
4687 unsigned long flags
;
4688 struct rq
*rq
= cpu_rq(cpu
);
4690 switch (action
& ~CPU_TASKS_FROZEN
) {
4692 case CPU_UP_PREPARE
:
4693 rq
->calc_load_update
= calc_load_update
;
4697 /* Update our root-domain */
4698 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4700 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
4704 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4707 #ifdef CONFIG_HOTPLUG_CPU
4709 sched_ttwu_pending();
4710 /* Update our root-domain */
4711 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4713 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
4717 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
4718 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4722 calc_load_migrate(rq
);
4727 update_max_interval();
4733 * Register at high priority so that task migration (migrate_all_tasks)
4734 * happens before everything else. This has to be lower priority than
4735 * the notifier in the perf_event subsystem, though.
4737 static struct notifier_block migration_notifier
= {
4738 .notifier_call
= migration_call
,
4739 .priority
= CPU_PRI_MIGRATION
,
4742 static int sched_cpu_active(struct notifier_block
*nfb
,
4743 unsigned long action
, void *hcpu
)
4745 switch (action
& ~CPU_TASKS_FROZEN
) {
4747 case CPU_DOWN_FAILED
:
4748 set_cpu_active((long)hcpu
, true);
4755 static int sched_cpu_inactive(struct notifier_block
*nfb
,
4756 unsigned long action
, void *hcpu
)
4758 switch (action
& ~CPU_TASKS_FROZEN
) {
4759 case CPU_DOWN_PREPARE
:
4760 set_cpu_active((long)hcpu
, false);
4767 static int __init
migration_init(void)
4769 void *cpu
= (void *)(long)smp_processor_id();
4772 /* Initialize migration for the boot CPU */
4773 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
4774 BUG_ON(err
== NOTIFY_BAD
);
4775 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
4776 register_cpu_notifier(&migration_notifier
);
4778 /* Register cpu active notifiers */
4779 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
4780 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
4784 early_initcall(migration_init
);
4789 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
4791 #ifdef CONFIG_SCHED_DEBUG
4793 static __read_mostly
int sched_debug_enabled
;
4795 static int __init
sched_debug_setup(char *str
)
4797 sched_debug_enabled
= 1;
4801 early_param("sched_debug", sched_debug_setup
);
4803 static inline bool sched_debug(void)
4805 return sched_debug_enabled
;
4808 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
4809 struct cpumask
*groupmask
)
4811 struct sched_group
*group
= sd
->groups
;
4814 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
4815 cpumask_clear(groupmask
);
4817 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
4819 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
4820 printk("does not load-balance\n");
4822 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
4827 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
4829 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
4830 printk(KERN_ERR
"ERROR: domain->span does not contain "
4833 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
4834 printk(KERN_ERR
"ERROR: domain->groups does not contain"
4838 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
4842 printk(KERN_ERR
"ERROR: group is NULL\n");
4847 * Even though we initialize ->power to something semi-sane,
4848 * we leave power_orig unset. This allows us to detect if
4849 * domain iteration is still funny without causing /0 traps.
4851 if (!group
->sgp
->power_orig
) {
4852 printk(KERN_CONT
"\n");
4853 printk(KERN_ERR
"ERROR: domain->cpu_power not "
4858 if (!cpumask_weight(sched_group_cpus(group
))) {
4859 printk(KERN_CONT
"\n");
4860 printk(KERN_ERR
"ERROR: empty group\n");
4864 if (!(sd
->flags
& SD_OVERLAP
) &&
4865 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
4866 printk(KERN_CONT
"\n");
4867 printk(KERN_ERR
"ERROR: repeated CPUs\n");
4871 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
4873 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
4875 printk(KERN_CONT
" %s", str
);
4876 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
4877 printk(KERN_CONT
" (cpu_power = %d)",
4881 group
= group
->next
;
4882 } while (group
!= sd
->groups
);
4883 printk(KERN_CONT
"\n");
4885 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
4886 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
4889 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
4890 printk(KERN_ERR
"ERROR: parent span is not a superset "
4891 "of domain->span\n");
4895 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
4899 if (!sched_debug_enabled
)
4903 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
4907 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
4910 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
4918 #else /* !CONFIG_SCHED_DEBUG */
4919 # define sched_domain_debug(sd, cpu) do { } while (0)
4920 static inline bool sched_debug(void)
4924 #endif /* CONFIG_SCHED_DEBUG */
4926 static int sd_degenerate(struct sched_domain
*sd
)
4928 if (cpumask_weight(sched_domain_span(sd
)) == 1)
4931 /* Following flags need at least 2 groups */
4932 if (sd
->flags
& (SD_LOAD_BALANCE
|
4933 SD_BALANCE_NEWIDLE
|
4937 SD_SHARE_PKG_RESOURCES
)) {
4938 if (sd
->groups
!= sd
->groups
->next
)
4942 /* Following flags don't use groups */
4943 if (sd
->flags
& (SD_WAKE_AFFINE
))
4950 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
4952 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
4954 if (sd_degenerate(parent
))
4957 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
4960 /* Flags needing groups don't count if only 1 group in parent */
4961 if (parent
->groups
== parent
->groups
->next
) {
4962 pflags
&= ~(SD_LOAD_BALANCE
|
4963 SD_BALANCE_NEWIDLE
|
4967 SD_SHARE_PKG_RESOURCES
);
4968 if (nr_node_ids
== 1)
4969 pflags
&= ~SD_SERIALIZE
;
4971 if (~cflags
& pflags
)
4977 static void free_rootdomain(struct rcu_head
*rcu
)
4979 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
4981 cpupri_cleanup(&rd
->cpupri
);
4982 free_cpumask_var(rd
->rto_mask
);
4983 free_cpumask_var(rd
->online
);
4984 free_cpumask_var(rd
->span
);
4988 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
4990 struct root_domain
*old_rd
= NULL
;
4991 unsigned long flags
;
4993 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4998 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5001 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5004 * If we dont want to free the old_rt yet then
5005 * set old_rd to NULL to skip the freeing later
5008 if (!atomic_dec_and_test(&old_rd
->refcount
))
5012 atomic_inc(&rd
->refcount
);
5015 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5016 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5019 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5022 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5025 static int init_rootdomain(struct root_domain
*rd
)
5027 memset(rd
, 0, sizeof(*rd
));
5029 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5031 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5033 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5036 if (cpupri_init(&rd
->cpupri
) != 0)
5041 free_cpumask_var(rd
->rto_mask
);
5043 free_cpumask_var(rd
->online
);
5045 free_cpumask_var(rd
->span
);
5051 * By default the system creates a single root-domain with all cpus as
5052 * members (mimicking the global state we have today).
5054 struct root_domain def_root_domain
;
5056 static void init_defrootdomain(void)
5058 init_rootdomain(&def_root_domain
);
5060 atomic_set(&def_root_domain
.refcount
, 1);
5063 static struct root_domain
*alloc_rootdomain(void)
5065 struct root_domain
*rd
;
5067 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5071 if (init_rootdomain(rd
) != 0) {
5079 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
5081 struct sched_group
*tmp
, *first
;
5090 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
5095 } while (sg
!= first
);
5098 static void free_sched_domain(struct rcu_head
*rcu
)
5100 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5103 * If its an overlapping domain it has private groups, iterate and
5106 if (sd
->flags
& SD_OVERLAP
) {
5107 free_sched_groups(sd
->groups
, 1);
5108 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5109 kfree(sd
->groups
->sgp
);
5115 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5117 call_rcu(&sd
->rcu
, free_sched_domain
);
5120 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5122 for (; sd
; sd
= sd
->parent
)
5123 destroy_sched_domain(sd
, cpu
);
5127 * Keep a special pointer to the highest sched_domain that has
5128 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5129 * allows us to avoid some pointer chasing select_idle_sibling().
5131 * Also keep a unique ID per domain (we use the first cpu number in
5132 * the cpumask of the domain), this allows us to quickly tell if
5133 * two cpus are in the same cache domain, see cpus_share_cache().
5135 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5136 DEFINE_PER_CPU(int, sd_llc_id
);
5138 static void update_top_cache_domain(int cpu
)
5140 struct sched_domain
*sd
;
5143 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5145 id
= cpumask_first(sched_domain_span(sd
));
5147 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5148 per_cpu(sd_llc_id
, cpu
) = id
;
5152 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5153 * hold the hotplug lock.
5156 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5158 struct rq
*rq
= cpu_rq(cpu
);
5159 struct sched_domain
*tmp
;
5161 /* Remove the sched domains which do not contribute to scheduling. */
5162 for (tmp
= sd
; tmp
; ) {
5163 struct sched_domain
*parent
= tmp
->parent
;
5167 if (sd_parent_degenerate(tmp
, parent
)) {
5168 tmp
->parent
= parent
->parent
;
5170 parent
->parent
->child
= tmp
;
5171 destroy_sched_domain(parent
, cpu
);
5176 if (sd
&& sd_degenerate(sd
)) {
5179 destroy_sched_domain(tmp
, cpu
);
5184 sched_domain_debug(sd
, cpu
);
5186 rq_attach_root(rq
, rd
);
5188 rcu_assign_pointer(rq
->sd
, sd
);
5189 destroy_sched_domains(tmp
, cpu
);
5191 update_top_cache_domain(cpu
);
5194 /* cpus with isolated domains */
5195 static cpumask_var_t cpu_isolated_map
;
5197 /* Setup the mask of cpus configured for isolated domains */
5198 static int __init
isolated_cpu_setup(char *str
)
5200 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5201 cpulist_parse(str
, cpu_isolated_map
);
5205 __setup("isolcpus=", isolated_cpu_setup
);
5207 static const struct cpumask
*cpu_cpu_mask(int cpu
)
5209 return cpumask_of_node(cpu_to_node(cpu
));
5213 struct sched_domain
**__percpu sd
;
5214 struct sched_group
**__percpu sg
;
5215 struct sched_group_power
**__percpu sgp
;
5219 struct sched_domain
** __percpu sd
;
5220 struct root_domain
*rd
;
5230 struct sched_domain_topology_level
;
5232 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
5233 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
5235 #define SDTL_OVERLAP 0x01
5237 struct sched_domain_topology_level
{
5238 sched_domain_init_f init
;
5239 sched_domain_mask_f mask
;
5242 struct sd_data data
;
5246 * Build an iteration mask that can exclude certain CPUs from the upwards
5249 * Asymmetric node setups can result in situations where the domain tree is of
5250 * unequal depth, make sure to skip domains that already cover the entire
5253 * In that case build_sched_domains() will have terminated the iteration early
5254 * and our sibling sd spans will be empty. Domains should always include the
5255 * cpu they're built on, so check that.
5258 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5260 const struct cpumask
*span
= sched_domain_span(sd
);
5261 struct sd_data
*sdd
= sd
->private;
5262 struct sched_domain
*sibling
;
5265 for_each_cpu(i
, span
) {
5266 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5267 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5270 cpumask_set_cpu(i
, sched_group_mask(sg
));
5275 * Return the canonical balance cpu for this group, this is the first cpu
5276 * of this group that's also in the iteration mask.
5278 int group_balance_cpu(struct sched_group
*sg
)
5280 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5284 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5286 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5287 const struct cpumask
*span
= sched_domain_span(sd
);
5288 struct cpumask
*covered
= sched_domains_tmpmask
;
5289 struct sd_data
*sdd
= sd
->private;
5290 struct sched_domain
*child
;
5293 cpumask_clear(covered
);
5295 for_each_cpu(i
, span
) {
5296 struct cpumask
*sg_span
;
5298 if (cpumask_test_cpu(i
, covered
))
5301 child
= *per_cpu_ptr(sdd
->sd
, i
);
5303 /* See the comment near build_group_mask(). */
5304 if (!cpumask_test_cpu(i
, sched_domain_span(child
)))
5307 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5308 GFP_KERNEL
, cpu_to_node(cpu
));
5313 sg_span
= sched_group_cpus(sg
);
5315 child
= child
->child
;
5316 cpumask_copy(sg_span
, sched_domain_span(child
));
5318 cpumask_set_cpu(i
, sg_span
);
5320 cpumask_or(covered
, covered
, sg_span
);
5322 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, i
);
5323 if (atomic_inc_return(&sg
->sgp
->ref
) == 1)
5324 build_group_mask(sd
, sg
);
5327 * Initialize sgp->power such that even if we mess up the
5328 * domains and no possible iteration will get us here, we won't
5331 sg
->sgp
->power
= SCHED_POWER_SCALE
* cpumask_weight(sg_span
);
5334 * Make sure the first group of this domain contains the
5335 * canonical balance cpu. Otherwise the sched_domain iteration
5336 * breaks. See update_sg_lb_stats().
5338 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5339 group_balance_cpu(sg
) == cpu
)
5349 sd
->groups
= groups
;
5354 free_sched_groups(first
, 0);
5359 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5361 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5362 struct sched_domain
*child
= sd
->child
;
5365 cpu
= cpumask_first(sched_domain_span(child
));
5368 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5369 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
5370 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
5377 * build_sched_groups will build a circular linked list of the groups
5378 * covered by the given span, and will set each group's ->cpumask correctly,
5379 * and ->cpu_power to 0.
5381 * Assumes the sched_domain tree is fully constructed
5384 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5386 struct sched_group
*first
= NULL
, *last
= NULL
;
5387 struct sd_data
*sdd
= sd
->private;
5388 const struct cpumask
*span
= sched_domain_span(sd
);
5389 struct cpumask
*covered
;
5392 get_group(cpu
, sdd
, &sd
->groups
);
5393 atomic_inc(&sd
->groups
->ref
);
5395 if (cpu
!= cpumask_first(span
))
5398 lockdep_assert_held(&sched_domains_mutex
);
5399 covered
= sched_domains_tmpmask
;
5401 cpumask_clear(covered
);
5403 for_each_cpu(i
, span
) {
5404 struct sched_group
*sg
;
5407 if (cpumask_test_cpu(i
, covered
))
5410 group
= get_group(i
, sdd
, &sg
);
5411 cpumask_clear(sched_group_cpus(sg
));
5413 cpumask_setall(sched_group_mask(sg
));
5415 for_each_cpu(j
, span
) {
5416 if (get_group(j
, sdd
, NULL
) != group
)
5419 cpumask_set_cpu(j
, covered
);
5420 cpumask_set_cpu(j
, sched_group_cpus(sg
));
5435 * Initialize sched groups cpu_power.
5437 * cpu_power indicates the capacity of sched group, which is used while
5438 * distributing the load between different sched groups in a sched domain.
5439 * Typically cpu_power for all the groups in a sched domain will be same unless
5440 * there are asymmetries in the topology. If there are asymmetries, group
5441 * having more cpu_power will pickup more load compared to the group having
5444 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
5446 struct sched_group
*sg
= sd
->groups
;
5451 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
5453 } while (sg
!= sd
->groups
);
5455 if (cpu
!= group_balance_cpu(sg
))
5458 update_group_power(sd
, cpu
);
5459 atomic_set(&sg
->sgp
->nr_busy_cpus
, sg
->group_weight
);
5462 int __weak
arch_sd_sibling_asym_packing(void)
5464 return 0*SD_ASYM_PACKING
;
5468 * Initializers for schedule domains
5469 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5472 #ifdef CONFIG_SCHED_DEBUG
5473 # define SD_INIT_NAME(sd, type) sd->name = #type
5475 # define SD_INIT_NAME(sd, type) do { } while (0)
5478 #define SD_INIT_FUNC(type) \
5479 static noinline struct sched_domain * \
5480 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
5482 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
5483 *sd = SD_##type##_INIT; \
5484 SD_INIT_NAME(sd, type); \
5485 sd->private = &tl->data; \
5490 #ifdef CONFIG_SCHED_SMT
5491 SD_INIT_FUNC(SIBLING
)
5493 #ifdef CONFIG_SCHED_MC
5496 #ifdef CONFIG_SCHED_BOOK
5500 static int default_relax_domain_level
= -1;
5501 int sched_domain_level_max
;
5503 static int __init
setup_relax_domain_level(char *str
)
5505 if (kstrtoint(str
, 0, &default_relax_domain_level
))
5506 pr_warn("Unable to set relax_domain_level\n");
5510 __setup("relax_domain_level=", setup_relax_domain_level
);
5512 static void set_domain_attribute(struct sched_domain
*sd
,
5513 struct sched_domain_attr
*attr
)
5517 if (!attr
|| attr
->relax_domain_level
< 0) {
5518 if (default_relax_domain_level
< 0)
5521 request
= default_relax_domain_level
;
5523 request
= attr
->relax_domain_level
;
5524 if (request
< sd
->level
) {
5525 /* turn off idle balance on this domain */
5526 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5528 /* turn on idle balance on this domain */
5529 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5533 static void __sdt_free(const struct cpumask
*cpu_map
);
5534 static int __sdt_alloc(const struct cpumask
*cpu_map
);
5536 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
5537 const struct cpumask
*cpu_map
)
5541 if (!atomic_read(&d
->rd
->refcount
))
5542 free_rootdomain(&d
->rd
->rcu
); /* fall through */
5544 free_percpu(d
->sd
); /* fall through */
5546 __sdt_free(cpu_map
); /* fall through */
5552 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
5553 const struct cpumask
*cpu_map
)
5555 memset(d
, 0, sizeof(*d
));
5557 if (__sdt_alloc(cpu_map
))
5558 return sa_sd_storage
;
5559 d
->sd
= alloc_percpu(struct sched_domain
*);
5561 return sa_sd_storage
;
5562 d
->rd
= alloc_rootdomain();
5565 return sa_rootdomain
;
5569 * NULL the sd_data elements we've used to build the sched_domain and
5570 * sched_group structure so that the subsequent __free_domain_allocs()
5571 * will not free the data we're using.
5573 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
5575 struct sd_data
*sdd
= sd
->private;
5577 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
5578 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
5580 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
5581 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
5583 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
5584 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
5587 #ifdef CONFIG_SCHED_SMT
5588 static const struct cpumask
*cpu_smt_mask(int cpu
)
5590 return topology_thread_cpumask(cpu
);
5595 * Topology list, bottom-up.
5597 static struct sched_domain_topology_level default_topology
[] = {
5598 #ifdef CONFIG_SCHED_SMT
5599 { sd_init_SIBLING
, cpu_smt_mask
, },
5601 #ifdef CONFIG_SCHED_MC
5602 { sd_init_MC
, cpu_coregroup_mask
, },
5604 #ifdef CONFIG_SCHED_BOOK
5605 { sd_init_BOOK
, cpu_book_mask
, },
5607 { sd_init_CPU
, cpu_cpu_mask
, },
5611 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
5613 #define for_each_sd_topology(tl) \
5614 for (tl = sched_domain_topology; tl->init; tl++)
5618 static int sched_domains_numa_levels
;
5619 static int *sched_domains_numa_distance
;
5620 static struct cpumask
***sched_domains_numa_masks
;
5621 static int sched_domains_curr_level
;
5623 static inline int sd_local_flags(int level
)
5625 if (sched_domains_numa_distance
[level
] > RECLAIM_DISTANCE
)
5628 return SD_BALANCE_EXEC
| SD_BALANCE_FORK
| SD_WAKE_AFFINE
;
5631 static struct sched_domain
*
5632 sd_numa_init(struct sched_domain_topology_level
*tl
, int cpu
)
5634 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
5635 int level
= tl
->numa_level
;
5636 int sd_weight
= cpumask_weight(
5637 sched_domains_numa_masks
[level
][cpu_to_node(cpu
)]);
5639 *sd
= (struct sched_domain
){
5640 .min_interval
= sd_weight
,
5641 .max_interval
= 2*sd_weight
,
5643 .imbalance_pct
= 125,
5644 .cache_nice_tries
= 2,
5651 .flags
= 1*SD_LOAD_BALANCE
5652 | 1*SD_BALANCE_NEWIDLE
5657 | 0*SD_SHARE_CPUPOWER
5658 | 0*SD_SHARE_PKG_RESOURCES
5660 | 0*SD_PREFER_SIBLING
5661 | sd_local_flags(level
)
5663 .last_balance
= jiffies
,
5664 .balance_interval
= sd_weight
,
5666 SD_INIT_NAME(sd
, NUMA
);
5667 sd
->private = &tl
->data
;
5670 * Ugly hack to pass state to sd_numa_mask()...
5672 sched_domains_curr_level
= tl
->numa_level
;
5677 static const struct cpumask
*sd_numa_mask(int cpu
)
5679 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
5682 static void sched_numa_warn(const char *str
)
5684 static int done
= false;
5692 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
5694 for (i
= 0; i
< nr_node_ids
; i
++) {
5695 printk(KERN_WARNING
" ");
5696 for (j
= 0; j
< nr_node_ids
; j
++)
5697 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
5698 printk(KERN_CONT
"\n");
5700 printk(KERN_WARNING
"\n");
5703 static bool find_numa_distance(int distance
)
5707 if (distance
== node_distance(0, 0))
5710 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5711 if (sched_domains_numa_distance
[i
] == distance
)
5718 static void sched_init_numa(void)
5720 int next_distance
, curr_distance
= node_distance(0, 0);
5721 struct sched_domain_topology_level
*tl
;
5725 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
5726 if (!sched_domains_numa_distance
)
5730 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
5731 * unique distances in the node_distance() table.
5733 * Assumes node_distance(0,j) includes all distances in
5734 * node_distance(i,j) in order to avoid cubic time.
5736 next_distance
= curr_distance
;
5737 for (i
= 0; i
< nr_node_ids
; i
++) {
5738 for (j
= 0; j
< nr_node_ids
; j
++) {
5739 for (k
= 0; k
< nr_node_ids
; k
++) {
5740 int distance
= node_distance(i
, k
);
5742 if (distance
> curr_distance
&&
5743 (distance
< next_distance
||
5744 next_distance
== curr_distance
))
5745 next_distance
= distance
;
5748 * While not a strong assumption it would be nice to know
5749 * about cases where if node A is connected to B, B is not
5750 * equally connected to A.
5752 if (sched_debug() && node_distance(k
, i
) != distance
)
5753 sched_numa_warn("Node-distance not symmetric");
5755 if (sched_debug() && i
&& !find_numa_distance(distance
))
5756 sched_numa_warn("Node-0 not representative");
5758 if (next_distance
!= curr_distance
) {
5759 sched_domains_numa_distance
[level
++] = next_distance
;
5760 sched_domains_numa_levels
= level
;
5761 curr_distance
= next_distance
;
5766 * In case of sched_debug() we verify the above assumption.
5772 * 'level' contains the number of unique distances, excluding the
5773 * identity distance node_distance(i,i).
5775 * The sched_domains_numa_distance[] array includes the actual distance
5780 * Here, we should temporarily reset sched_domains_numa_levels to 0.
5781 * If it fails to allocate memory for array sched_domains_numa_masks[][],
5782 * the array will contain less then 'level' members. This could be
5783 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
5784 * in other functions.
5786 * We reset it to 'level' at the end of this function.
5788 sched_domains_numa_levels
= 0;
5790 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
5791 if (!sched_domains_numa_masks
)
5795 * Now for each level, construct a mask per node which contains all
5796 * cpus of nodes that are that many hops away from us.
5798 for (i
= 0; i
< level
; i
++) {
5799 sched_domains_numa_masks
[i
] =
5800 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
5801 if (!sched_domains_numa_masks
[i
])
5804 for (j
= 0; j
< nr_node_ids
; j
++) {
5805 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
5809 sched_domains_numa_masks
[i
][j
] = mask
;
5811 for (k
= 0; k
< nr_node_ids
; k
++) {
5812 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
5815 cpumask_or(mask
, mask
, cpumask_of_node(k
));
5820 tl
= kzalloc((ARRAY_SIZE(default_topology
) + level
) *
5821 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
5826 * Copy the default topology bits..
5828 for (i
= 0; default_topology
[i
].init
; i
++)
5829 tl
[i
] = default_topology
[i
];
5832 * .. and append 'j' levels of NUMA goodness.
5834 for (j
= 0; j
< level
; i
++, j
++) {
5835 tl
[i
] = (struct sched_domain_topology_level
){
5836 .init
= sd_numa_init
,
5837 .mask
= sd_numa_mask
,
5838 .flags
= SDTL_OVERLAP
,
5843 sched_domain_topology
= tl
;
5845 sched_domains_numa_levels
= level
;
5848 static void sched_domains_numa_masks_set(int cpu
)
5851 int node
= cpu_to_node(cpu
);
5853 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5854 for (j
= 0; j
< nr_node_ids
; j
++) {
5855 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
5856 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
5861 static void sched_domains_numa_masks_clear(int cpu
)
5864 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5865 for (j
= 0; j
< nr_node_ids
; j
++)
5866 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
5871 * Update sched_domains_numa_masks[level][node] array when new cpus
5874 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
5875 unsigned long action
,
5878 int cpu
= (long)hcpu
;
5880 switch (action
& ~CPU_TASKS_FROZEN
) {
5882 sched_domains_numa_masks_set(cpu
);
5886 sched_domains_numa_masks_clear(cpu
);
5896 static inline void sched_init_numa(void)
5900 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
5901 unsigned long action
,
5906 #endif /* CONFIG_NUMA */
5908 static int __sdt_alloc(const struct cpumask
*cpu_map
)
5910 struct sched_domain_topology_level
*tl
;
5913 for_each_sd_topology(tl
) {
5914 struct sd_data
*sdd
= &tl
->data
;
5916 sdd
->sd
= alloc_percpu(struct sched_domain
*);
5920 sdd
->sg
= alloc_percpu(struct sched_group
*);
5924 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
5928 for_each_cpu(j
, cpu_map
) {
5929 struct sched_domain
*sd
;
5930 struct sched_group
*sg
;
5931 struct sched_group_power
*sgp
;
5933 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
5934 GFP_KERNEL
, cpu_to_node(j
));
5938 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
5940 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5941 GFP_KERNEL
, cpu_to_node(j
));
5947 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
5949 sgp
= kzalloc_node(sizeof(struct sched_group_power
) + cpumask_size(),
5950 GFP_KERNEL
, cpu_to_node(j
));
5954 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
5961 static void __sdt_free(const struct cpumask
*cpu_map
)
5963 struct sched_domain_topology_level
*tl
;
5966 for_each_sd_topology(tl
) {
5967 struct sd_data
*sdd
= &tl
->data
;
5969 for_each_cpu(j
, cpu_map
) {
5970 struct sched_domain
*sd
;
5973 sd
= *per_cpu_ptr(sdd
->sd
, j
);
5974 if (sd
&& (sd
->flags
& SD_OVERLAP
))
5975 free_sched_groups(sd
->groups
, 0);
5976 kfree(*per_cpu_ptr(sdd
->sd
, j
));
5980 kfree(*per_cpu_ptr(sdd
->sg
, j
));
5982 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
5984 free_percpu(sdd
->sd
);
5986 free_percpu(sdd
->sg
);
5988 free_percpu(sdd
->sgp
);
5993 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
5994 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
5995 struct sched_domain
*child
, int cpu
)
5997 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
6001 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6003 sd
->level
= child
->level
+ 1;
6004 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6008 set_domain_attribute(sd
, attr
);
6014 * Build sched domains for a given set of cpus and attach the sched domains
6015 * to the individual cpus
6017 static int build_sched_domains(const struct cpumask
*cpu_map
,
6018 struct sched_domain_attr
*attr
)
6020 enum s_alloc alloc_state
;
6021 struct sched_domain
*sd
;
6023 int i
, ret
= -ENOMEM
;
6025 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6026 if (alloc_state
!= sa_rootdomain
)
6029 /* Set up domains for cpus specified by the cpu_map. */
6030 for_each_cpu(i
, cpu_map
) {
6031 struct sched_domain_topology_level
*tl
;
6034 for_each_sd_topology(tl
) {
6035 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6036 if (tl
== sched_domain_topology
)
6037 *per_cpu_ptr(d
.sd
, i
) = sd
;
6038 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6039 sd
->flags
|= SD_OVERLAP
;
6040 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6045 /* Build the groups for the domains */
6046 for_each_cpu(i
, cpu_map
) {
6047 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6048 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6049 if (sd
->flags
& SD_OVERLAP
) {
6050 if (build_overlap_sched_groups(sd
, i
))
6053 if (build_sched_groups(sd
, i
))
6059 /* Calculate CPU power for physical packages and nodes */
6060 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6061 if (!cpumask_test_cpu(i
, cpu_map
))
6064 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6065 claim_allocations(i
, sd
);
6066 init_sched_groups_power(i
, sd
);
6070 /* Attach the domains */
6072 for_each_cpu(i
, cpu_map
) {
6073 sd
= *per_cpu_ptr(d
.sd
, i
);
6074 cpu_attach_domain(sd
, d
.rd
, i
);
6080 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6084 static cpumask_var_t
*doms_cur
; /* current sched domains */
6085 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6086 static struct sched_domain_attr
*dattr_cur
;
6087 /* attribues of custom domains in 'doms_cur' */
6090 * Special case: If a kmalloc of a doms_cur partition (array of
6091 * cpumask) fails, then fallback to a single sched domain,
6092 * as determined by the single cpumask fallback_doms.
6094 static cpumask_var_t fallback_doms
;
6097 * arch_update_cpu_topology lets virtualized architectures update the
6098 * cpu core maps. It is supposed to return 1 if the topology changed
6099 * or 0 if it stayed the same.
6101 int __attribute__((weak
)) arch_update_cpu_topology(void)
6106 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6109 cpumask_var_t
*doms
;
6111 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6114 for (i
= 0; i
< ndoms
; i
++) {
6115 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6116 free_sched_domains(doms
, i
);
6123 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6126 for (i
= 0; i
< ndoms
; i
++)
6127 free_cpumask_var(doms
[i
]);
6132 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6133 * For now this just excludes isolated cpus, but could be used to
6134 * exclude other special cases in the future.
6136 static int init_sched_domains(const struct cpumask
*cpu_map
)
6140 arch_update_cpu_topology();
6142 doms_cur
= alloc_sched_domains(ndoms_cur
);
6144 doms_cur
= &fallback_doms
;
6145 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6146 err
= build_sched_domains(doms_cur
[0], NULL
);
6147 register_sched_domain_sysctl();
6153 * Detach sched domains from a group of cpus specified in cpu_map
6154 * These cpus will now be attached to the NULL domain
6156 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6161 for_each_cpu(i
, cpu_map
)
6162 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6166 /* handle null as "default" */
6167 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6168 struct sched_domain_attr
*new, int idx_new
)
6170 struct sched_domain_attr tmp
;
6177 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6178 new ? (new + idx_new
) : &tmp
,
6179 sizeof(struct sched_domain_attr
));
6183 * Partition sched domains as specified by the 'ndoms_new'
6184 * cpumasks in the array doms_new[] of cpumasks. This compares
6185 * doms_new[] to the current sched domain partitioning, doms_cur[].
6186 * It destroys each deleted domain and builds each new domain.
6188 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6189 * The masks don't intersect (don't overlap.) We should setup one
6190 * sched domain for each mask. CPUs not in any of the cpumasks will
6191 * not be load balanced. If the same cpumask appears both in the
6192 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6195 * The passed in 'doms_new' should be allocated using
6196 * alloc_sched_domains. This routine takes ownership of it and will
6197 * free_sched_domains it when done with it. If the caller failed the
6198 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6199 * and partition_sched_domains() will fallback to the single partition
6200 * 'fallback_doms', it also forces the domains to be rebuilt.
6202 * If doms_new == NULL it will be replaced with cpu_online_mask.
6203 * ndoms_new == 0 is a special case for destroying existing domains,
6204 * and it will not create the default domain.
6206 * Call with hotplug lock held
6208 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6209 struct sched_domain_attr
*dattr_new
)
6214 mutex_lock(&sched_domains_mutex
);
6216 /* always unregister in case we don't destroy any domains */
6217 unregister_sched_domain_sysctl();
6219 /* Let architecture update cpu core mappings. */
6220 new_topology
= arch_update_cpu_topology();
6222 n
= doms_new
? ndoms_new
: 0;
6224 /* Destroy deleted domains */
6225 for (i
= 0; i
< ndoms_cur
; i
++) {
6226 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6227 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6228 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6231 /* no match - a current sched domain not in new doms_new[] */
6232 detach_destroy_domains(doms_cur
[i
]);
6237 if (doms_new
== NULL
) {
6239 doms_new
= &fallback_doms
;
6240 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6241 WARN_ON_ONCE(dattr_new
);
6244 /* Build new domains */
6245 for (i
= 0; i
< ndoms_new
; i
++) {
6246 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
6247 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6248 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6251 /* no match - add a new doms_new */
6252 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6257 /* Remember the new sched domains */
6258 if (doms_cur
!= &fallback_doms
)
6259 free_sched_domains(doms_cur
, ndoms_cur
);
6260 kfree(dattr_cur
); /* kfree(NULL) is safe */
6261 doms_cur
= doms_new
;
6262 dattr_cur
= dattr_new
;
6263 ndoms_cur
= ndoms_new
;
6265 register_sched_domain_sysctl();
6267 mutex_unlock(&sched_domains_mutex
);
6270 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6273 * Update cpusets according to cpu_active mask. If cpusets are
6274 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6275 * around partition_sched_domains().
6277 * If we come here as part of a suspend/resume, don't touch cpusets because we
6278 * want to restore it back to its original state upon resume anyway.
6280 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6284 case CPU_ONLINE_FROZEN
:
6285 case CPU_DOWN_FAILED_FROZEN
:
6288 * num_cpus_frozen tracks how many CPUs are involved in suspend
6289 * resume sequence. As long as this is not the last online
6290 * operation in the resume sequence, just build a single sched
6291 * domain, ignoring cpusets.
6294 if (likely(num_cpus_frozen
)) {
6295 partition_sched_domains(1, NULL
, NULL
);
6300 * This is the last CPU online operation. So fall through and
6301 * restore the original sched domains by considering the
6302 * cpuset configurations.
6306 case CPU_DOWN_FAILED
:
6307 cpuset_update_active_cpus(true);
6315 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6319 case CPU_DOWN_PREPARE
:
6320 cpuset_update_active_cpus(false);
6322 case CPU_DOWN_PREPARE_FROZEN
:
6324 partition_sched_domains(1, NULL
, NULL
);
6332 void __init
sched_init_smp(void)
6334 cpumask_var_t non_isolated_cpus
;
6336 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6337 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6342 mutex_lock(&sched_domains_mutex
);
6343 init_sched_domains(cpu_active_mask
);
6344 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6345 if (cpumask_empty(non_isolated_cpus
))
6346 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6347 mutex_unlock(&sched_domains_mutex
);
6350 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
6351 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6352 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6356 /* Move init over to a non-isolated CPU */
6357 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6359 sched_init_granularity();
6360 free_cpumask_var(non_isolated_cpus
);
6362 init_sched_rt_class();
6365 void __init
sched_init_smp(void)
6367 sched_init_granularity();
6369 #endif /* CONFIG_SMP */
6371 const_debug
unsigned int sysctl_timer_migration
= 1;
6373 int in_sched_functions(unsigned long addr
)
6375 return in_lock_functions(addr
) ||
6376 (addr
>= (unsigned long)__sched_text_start
6377 && addr
< (unsigned long)__sched_text_end
);
6380 #ifdef CONFIG_CGROUP_SCHED
6382 * Default task group.
6383 * Every task in system belongs to this group at bootup.
6385 struct task_group root_task_group
;
6386 LIST_HEAD(task_groups
);
6389 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
6391 void __init
sched_init(void)
6394 unsigned long alloc_size
= 0, ptr
;
6396 #ifdef CONFIG_FAIR_GROUP_SCHED
6397 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6399 #ifdef CONFIG_RT_GROUP_SCHED
6400 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6402 #ifdef CONFIG_CPUMASK_OFFSTACK
6403 alloc_size
+= num_possible_cpus() * cpumask_size();
6406 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6408 #ifdef CONFIG_FAIR_GROUP_SCHED
6409 root_task_group
.se
= (struct sched_entity
**)ptr
;
6410 ptr
+= nr_cpu_ids
* sizeof(void **);
6412 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6413 ptr
+= nr_cpu_ids
* sizeof(void **);
6415 #endif /* CONFIG_FAIR_GROUP_SCHED */
6416 #ifdef CONFIG_RT_GROUP_SCHED
6417 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6418 ptr
+= nr_cpu_ids
* sizeof(void **);
6420 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6421 ptr
+= nr_cpu_ids
* sizeof(void **);
6423 #endif /* CONFIG_RT_GROUP_SCHED */
6424 #ifdef CONFIG_CPUMASK_OFFSTACK
6425 for_each_possible_cpu(i
) {
6426 per_cpu(load_balance_mask
, i
) = (void *)ptr
;
6427 ptr
+= cpumask_size();
6429 #endif /* CONFIG_CPUMASK_OFFSTACK */
6433 init_defrootdomain();
6436 init_rt_bandwidth(&def_rt_bandwidth
,
6437 global_rt_period(), global_rt_runtime());
6439 #ifdef CONFIG_RT_GROUP_SCHED
6440 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6441 global_rt_period(), global_rt_runtime());
6442 #endif /* CONFIG_RT_GROUP_SCHED */
6444 #ifdef CONFIG_CGROUP_SCHED
6445 list_add(&root_task_group
.list
, &task_groups
);
6446 INIT_LIST_HEAD(&root_task_group
.children
);
6447 INIT_LIST_HEAD(&root_task_group
.siblings
);
6448 autogroup_init(&init_task
);
6450 #endif /* CONFIG_CGROUP_SCHED */
6452 for_each_possible_cpu(i
) {
6456 raw_spin_lock_init(&rq
->lock
);
6458 rq
->calc_load_active
= 0;
6459 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6460 init_cfs_rq(&rq
->cfs
);
6461 init_rt_rq(&rq
->rt
, rq
);
6462 #ifdef CONFIG_FAIR_GROUP_SCHED
6463 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6464 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6466 * How much cpu bandwidth does root_task_group get?
6468 * In case of task-groups formed thr' the cgroup filesystem, it
6469 * gets 100% of the cpu resources in the system. This overall
6470 * system cpu resource is divided among the tasks of
6471 * root_task_group and its child task-groups in a fair manner,
6472 * based on each entity's (task or task-group's) weight
6473 * (se->load.weight).
6475 * In other words, if root_task_group has 10 tasks of weight
6476 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6477 * then A0's share of the cpu resource is:
6479 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6481 * We achieve this by letting root_task_group's tasks sit
6482 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6484 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6485 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6486 #endif /* CONFIG_FAIR_GROUP_SCHED */
6488 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6489 #ifdef CONFIG_RT_GROUP_SCHED
6490 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
6491 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6494 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6495 rq
->cpu_load
[j
] = 0;
6497 rq
->last_load_update_tick
= jiffies
;
6502 rq
->cpu_power
= SCHED_POWER_SCALE
;
6503 rq
->post_schedule
= 0;
6504 rq
->active_balance
= 0;
6505 rq
->next_balance
= jiffies
;
6510 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
6512 INIT_LIST_HEAD(&rq
->cfs_tasks
);
6514 rq_attach_root(rq
, &def_root_domain
);
6515 #ifdef CONFIG_NO_HZ_COMMON
6518 #ifdef CONFIG_NO_HZ_FULL
6519 rq
->last_sched_tick
= 0;
6523 atomic_set(&rq
->nr_iowait
, 0);
6526 set_load_weight(&init_task
);
6528 #ifdef CONFIG_PREEMPT_NOTIFIERS
6529 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
6532 #ifdef CONFIG_RT_MUTEXES
6533 plist_head_init(&init_task
.pi_waiters
);
6537 * The boot idle thread does lazy MMU switching as well:
6539 atomic_inc(&init_mm
.mm_count
);
6540 enter_lazy_tlb(&init_mm
, current
);
6543 * Make us the idle thread. Technically, schedule() should not be
6544 * called from this thread, however somewhere below it might be,
6545 * but because we are the idle thread, we just pick up running again
6546 * when this runqueue becomes "idle".
6548 init_idle(current
, smp_processor_id());
6550 calc_load_update
= jiffies
+ LOAD_FREQ
;
6553 * During early bootup we pretend to be a normal task:
6555 current
->sched_class
= &fair_sched_class
;
6558 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
6559 /* May be allocated at isolcpus cmdline parse time */
6560 if (cpu_isolated_map
== NULL
)
6561 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
6562 idle_thread_set_boot_cpu();
6564 init_sched_fair_class();
6566 scheduler_running
= 1;
6569 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6570 static inline int preempt_count_equals(int preempt_offset
)
6572 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
6574 return (nested
== preempt_offset
);
6577 void __might_sleep(const char *file
, int line
, int preempt_offset
)
6579 static unsigned long prev_jiffy
; /* ratelimiting */
6581 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
6582 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
6583 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
6585 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
6587 prev_jiffy
= jiffies
;
6590 "BUG: sleeping function called from invalid context at %s:%d\n",
6593 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
6594 in_atomic(), irqs_disabled(),
6595 current
->pid
, current
->comm
);
6597 debug_show_held_locks(current
);
6598 if (irqs_disabled())
6599 print_irqtrace_events(current
);
6602 EXPORT_SYMBOL(__might_sleep
);
6605 #ifdef CONFIG_MAGIC_SYSRQ
6606 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
6608 const struct sched_class
*prev_class
= p
->sched_class
;
6609 int old_prio
= p
->prio
;
6614 dequeue_task(rq
, p
, 0);
6615 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
6617 enqueue_task(rq
, p
, 0);
6618 resched_task(rq
->curr
);
6621 check_class_changed(rq
, p
, prev_class
, old_prio
);
6624 void normalize_rt_tasks(void)
6626 struct task_struct
*g
, *p
;
6627 unsigned long flags
;
6630 read_lock_irqsave(&tasklist_lock
, flags
);
6631 do_each_thread(g
, p
) {
6633 * Only normalize user tasks:
6638 p
->se
.exec_start
= 0;
6639 #ifdef CONFIG_SCHEDSTATS
6640 p
->se
.statistics
.wait_start
= 0;
6641 p
->se
.statistics
.sleep_start
= 0;
6642 p
->se
.statistics
.block_start
= 0;
6647 * Renice negative nice level userspace
6650 if (TASK_NICE(p
) < 0 && p
->mm
)
6651 set_user_nice(p
, 0);
6655 raw_spin_lock(&p
->pi_lock
);
6656 rq
= __task_rq_lock(p
);
6658 normalize_task(rq
, p
);
6660 __task_rq_unlock(rq
);
6661 raw_spin_unlock(&p
->pi_lock
);
6662 } while_each_thread(g
, p
);
6664 read_unlock_irqrestore(&tasklist_lock
, flags
);
6667 #endif /* CONFIG_MAGIC_SYSRQ */
6669 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
6671 * These functions are only useful for the IA64 MCA handling, or kdb.
6673 * They can only be called when the whole system has been
6674 * stopped - every CPU needs to be quiescent, and no scheduling
6675 * activity can take place. Using them for anything else would
6676 * be a serious bug, and as a result, they aren't even visible
6677 * under any other configuration.
6681 * curr_task - return the current task for a given cpu.
6682 * @cpu: the processor in question.
6684 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6686 * Return: The current task for @cpu.
6688 struct task_struct
*curr_task(int cpu
)
6690 return cpu_curr(cpu
);
6693 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
6697 * set_curr_task - set the current task for a given cpu.
6698 * @cpu: the processor in question.
6699 * @p: the task pointer to set.
6701 * Description: This function must only be used when non-maskable interrupts
6702 * are serviced on a separate stack. It allows the architecture to switch the
6703 * notion of the current task on a cpu in a non-blocking manner. This function
6704 * must be called with all CPU's synchronized, and interrupts disabled, the
6705 * and caller must save the original value of the current task (see
6706 * curr_task() above) and restore that value before reenabling interrupts and
6707 * re-starting the system.
6709 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6711 void set_curr_task(int cpu
, struct task_struct
*p
)
6718 #ifdef CONFIG_CGROUP_SCHED
6719 /* task_group_lock serializes the addition/removal of task groups */
6720 static DEFINE_SPINLOCK(task_group_lock
);
6722 static void free_sched_group(struct task_group
*tg
)
6724 free_fair_sched_group(tg
);
6725 free_rt_sched_group(tg
);
6730 /* allocate runqueue etc for a new task group */
6731 struct task_group
*sched_create_group(struct task_group
*parent
)
6733 struct task_group
*tg
;
6735 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
6737 return ERR_PTR(-ENOMEM
);
6739 if (!alloc_fair_sched_group(tg
, parent
))
6742 if (!alloc_rt_sched_group(tg
, parent
))
6748 free_sched_group(tg
);
6749 return ERR_PTR(-ENOMEM
);
6752 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
6754 unsigned long flags
;
6756 spin_lock_irqsave(&task_group_lock
, flags
);
6757 list_add_rcu(&tg
->list
, &task_groups
);
6759 WARN_ON(!parent
); /* root should already exist */
6761 tg
->parent
= parent
;
6762 INIT_LIST_HEAD(&tg
->children
);
6763 list_add_rcu(&tg
->siblings
, &parent
->children
);
6764 spin_unlock_irqrestore(&task_group_lock
, flags
);
6767 /* rcu callback to free various structures associated with a task group */
6768 static void free_sched_group_rcu(struct rcu_head
*rhp
)
6770 /* now it should be safe to free those cfs_rqs */
6771 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
6774 /* Destroy runqueue etc associated with a task group */
6775 void sched_destroy_group(struct task_group
*tg
)
6777 /* wait for possible concurrent references to cfs_rqs complete */
6778 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
6781 void sched_offline_group(struct task_group
*tg
)
6783 unsigned long flags
;
6786 /* end participation in shares distribution */
6787 for_each_possible_cpu(i
)
6788 unregister_fair_sched_group(tg
, i
);
6790 spin_lock_irqsave(&task_group_lock
, flags
);
6791 list_del_rcu(&tg
->list
);
6792 list_del_rcu(&tg
->siblings
);
6793 spin_unlock_irqrestore(&task_group_lock
, flags
);
6796 /* change task's runqueue when it moves between groups.
6797 * The caller of this function should have put the task in its new group
6798 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
6799 * reflect its new group.
6801 void sched_move_task(struct task_struct
*tsk
)
6803 struct task_group
*tg
;
6805 unsigned long flags
;
6808 rq
= task_rq_lock(tsk
, &flags
);
6810 running
= task_current(rq
, tsk
);
6814 dequeue_task(rq
, tsk
, 0);
6815 if (unlikely(running
))
6816 tsk
->sched_class
->put_prev_task(rq
, tsk
);
6818 tg
= container_of(task_subsys_state_check(tsk
, cpu_cgroup_subsys_id
,
6819 lockdep_is_held(&tsk
->sighand
->siglock
)),
6820 struct task_group
, css
);
6821 tg
= autogroup_task_group(tsk
, tg
);
6822 tsk
->sched_task_group
= tg
;
6824 #ifdef CONFIG_FAIR_GROUP_SCHED
6825 if (tsk
->sched_class
->task_move_group
)
6826 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
6829 set_task_rq(tsk
, task_cpu(tsk
));
6831 if (unlikely(running
))
6832 tsk
->sched_class
->set_curr_task(rq
);
6834 enqueue_task(rq
, tsk
, 0);
6836 task_rq_unlock(rq
, tsk
, &flags
);
6838 #endif /* CONFIG_CGROUP_SCHED */
6840 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
6841 static unsigned long to_ratio(u64 period
, u64 runtime
)
6843 if (runtime
== RUNTIME_INF
)
6846 return div64_u64(runtime
<< 20, period
);
6850 #ifdef CONFIG_RT_GROUP_SCHED
6852 * Ensure that the real time constraints are schedulable.
6854 static DEFINE_MUTEX(rt_constraints_mutex
);
6856 /* Must be called with tasklist_lock held */
6857 static inline int tg_has_rt_tasks(struct task_group
*tg
)
6859 struct task_struct
*g
, *p
;
6861 do_each_thread(g
, p
) {
6862 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
6864 } while_each_thread(g
, p
);
6869 struct rt_schedulable_data
{
6870 struct task_group
*tg
;
6875 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
6877 struct rt_schedulable_data
*d
= data
;
6878 struct task_group
*child
;
6879 unsigned long total
, sum
= 0;
6880 u64 period
, runtime
;
6882 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
6883 runtime
= tg
->rt_bandwidth
.rt_runtime
;
6886 period
= d
->rt_period
;
6887 runtime
= d
->rt_runtime
;
6891 * Cannot have more runtime than the period.
6893 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
6897 * Ensure we don't starve existing RT tasks.
6899 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
6902 total
= to_ratio(period
, runtime
);
6905 * Nobody can have more than the global setting allows.
6907 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
6911 * The sum of our children's runtime should not exceed our own.
6913 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
6914 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
6915 runtime
= child
->rt_bandwidth
.rt_runtime
;
6917 if (child
== d
->tg
) {
6918 period
= d
->rt_period
;
6919 runtime
= d
->rt_runtime
;
6922 sum
+= to_ratio(period
, runtime
);
6931 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
6935 struct rt_schedulable_data data
= {
6937 .rt_period
= period
,
6938 .rt_runtime
= runtime
,
6942 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
6948 static int tg_set_rt_bandwidth(struct task_group
*tg
,
6949 u64 rt_period
, u64 rt_runtime
)
6953 mutex_lock(&rt_constraints_mutex
);
6954 read_lock(&tasklist_lock
);
6955 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
6959 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
6960 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
6961 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
6963 for_each_possible_cpu(i
) {
6964 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
6966 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
6967 rt_rq
->rt_runtime
= rt_runtime
;
6968 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
6970 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
6972 read_unlock(&tasklist_lock
);
6973 mutex_unlock(&rt_constraints_mutex
);
6978 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
6980 u64 rt_runtime
, rt_period
;
6982 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
6983 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
6984 if (rt_runtime_us
< 0)
6985 rt_runtime
= RUNTIME_INF
;
6987 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
6990 static long sched_group_rt_runtime(struct task_group
*tg
)
6994 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
6997 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
6998 do_div(rt_runtime_us
, NSEC_PER_USEC
);
6999 return rt_runtime_us
;
7002 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7004 u64 rt_runtime
, rt_period
;
7006 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7007 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7012 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7015 static long sched_group_rt_period(struct task_group
*tg
)
7019 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7020 do_div(rt_period_us
, NSEC_PER_USEC
);
7021 return rt_period_us
;
7024 static int sched_rt_global_constraints(void)
7026 u64 runtime
, period
;
7029 if (sysctl_sched_rt_period
<= 0)
7032 runtime
= global_rt_runtime();
7033 period
= global_rt_period();
7036 * Sanity check on the sysctl variables.
7038 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7041 mutex_lock(&rt_constraints_mutex
);
7042 read_lock(&tasklist_lock
);
7043 ret
= __rt_schedulable(NULL
, 0, 0);
7044 read_unlock(&tasklist_lock
);
7045 mutex_unlock(&rt_constraints_mutex
);
7050 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7052 /* Don't accept realtime tasks when there is no way for them to run */
7053 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7059 #else /* !CONFIG_RT_GROUP_SCHED */
7060 static int sched_rt_global_constraints(void)
7062 unsigned long flags
;
7065 if (sysctl_sched_rt_period
<= 0)
7069 * There's always some RT tasks in the root group
7070 * -- migration, kstopmachine etc..
7072 if (sysctl_sched_rt_runtime
== 0)
7075 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7076 for_each_possible_cpu(i
) {
7077 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7079 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7080 rt_rq
->rt_runtime
= global_rt_runtime();
7081 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7083 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7087 #endif /* CONFIG_RT_GROUP_SCHED */
7089 int sched_rr_handler(struct ctl_table
*table
, int write
,
7090 void __user
*buffer
, size_t *lenp
,
7094 static DEFINE_MUTEX(mutex
);
7097 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7098 /* make sure that internally we keep jiffies */
7099 /* also, writing zero resets timeslice to default */
7100 if (!ret
&& write
) {
7101 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7102 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7104 mutex_unlock(&mutex
);
7108 int sched_rt_handler(struct ctl_table
*table
, int write
,
7109 void __user
*buffer
, size_t *lenp
,
7113 int old_period
, old_runtime
;
7114 static DEFINE_MUTEX(mutex
);
7117 old_period
= sysctl_sched_rt_period
;
7118 old_runtime
= sysctl_sched_rt_runtime
;
7120 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7122 if (!ret
&& write
) {
7123 ret
= sched_rt_global_constraints();
7125 sysctl_sched_rt_period
= old_period
;
7126 sysctl_sched_rt_runtime
= old_runtime
;
7128 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7129 def_rt_bandwidth
.rt_period
=
7130 ns_to_ktime(global_rt_period());
7133 mutex_unlock(&mutex
);
7138 #ifdef CONFIG_CGROUP_SCHED
7140 /* return corresponding task_group object of a cgroup */
7141 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
7143 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
7144 struct task_group
, css
);
7147 static struct cgroup_subsys_state
*cpu_cgroup_css_alloc(struct cgroup
*cgrp
)
7149 struct task_group
*tg
, *parent
;
7151 if (!cgrp
->parent
) {
7152 /* This is early initialization for the top cgroup */
7153 return &root_task_group
.css
;
7156 parent
= cgroup_tg(cgrp
->parent
);
7157 tg
= sched_create_group(parent
);
7159 return ERR_PTR(-ENOMEM
);
7164 static int cpu_cgroup_css_online(struct cgroup
*cgrp
)
7166 struct task_group
*tg
= cgroup_tg(cgrp
);
7167 struct task_group
*parent
;
7172 parent
= cgroup_tg(cgrp
->parent
);
7173 sched_online_group(tg
, parent
);
7177 static void cpu_cgroup_css_free(struct cgroup
*cgrp
)
7179 struct task_group
*tg
= cgroup_tg(cgrp
);
7181 sched_destroy_group(tg
);
7184 static void cpu_cgroup_css_offline(struct cgroup
*cgrp
)
7186 struct task_group
*tg
= cgroup_tg(cgrp
);
7188 sched_offline_group(tg
);
7191 static int cpu_cgroup_can_attach(struct cgroup
*cgrp
,
7192 struct cgroup_taskset
*tset
)
7194 struct task_struct
*task
;
7196 cgroup_taskset_for_each(task
, cgrp
, tset
) {
7197 #ifdef CONFIG_RT_GROUP_SCHED
7198 if (!sched_rt_can_attach(cgroup_tg(cgrp
), task
))
7201 /* We don't support RT-tasks being in separate groups */
7202 if (task
->sched_class
!= &fair_sched_class
)
7209 static void cpu_cgroup_attach(struct cgroup
*cgrp
,
7210 struct cgroup_taskset
*tset
)
7212 struct task_struct
*task
;
7214 cgroup_taskset_for_each(task
, cgrp
, tset
)
7215 sched_move_task(task
);
7219 cpu_cgroup_exit(struct cgroup
*cgrp
, struct cgroup
*old_cgrp
,
7220 struct task_struct
*task
)
7223 * cgroup_exit() is called in the copy_process() failure path.
7224 * Ignore this case since the task hasn't ran yet, this avoids
7225 * trying to poke a half freed task state from generic code.
7227 if (!(task
->flags
& PF_EXITING
))
7230 sched_move_task(task
);
7233 #ifdef CONFIG_FAIR_GROUP_SCHED
7234 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7237 return sched_group_set_shares(cgroup_tg(cgrp
), scale_load(shareval
));
7240 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7242 struct task_group
*tg
= cgroup_tg(cgrp
);
7244 return (u64
) scale_load_down(tg
->shares
);
7247 #ifdef CONFIG_CFS_BANDWIDTH
7248 static DEFINE_MUTEX(cfs_constraints_mutex
);
7250 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7251 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7253 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7255 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7257 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7258 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7260 if (tg
== &root_task_group
)
7264 * Ensure we have at some amount of bandwidth every period. This is
7265 * to prevent reaching a state of large arrears when throttled via
7266 * entity_tick() resulting in prolonged exit starvation.
7268 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7272 * Likewise, bound things on the otherside by preventing insane quota
7273 * periods. This also allows us to normalize in computing quota
7276 if (period
> max_cfs_quota_period
)
7279 mutex_lock(&cfs_constraints_mutex
);
7280 ret
= __cfs_schedulable(tg
, period
, quota
);
7284 runtime_enabled
= quota
!= RUNTIME_INF
;
7285 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7286 account_cfs_bandwidth_used(runtime_enabled
, runtime_was_enabled
);
7287 raw_spin_lock_irq(&cfs_b
->lock
);
7288 cfs_b
->period
= ns_to_ktime(period
);
7289 cfs_b
->quota
= quota
;
7291 __refill_cfs_bandwidth_runtime(cfs_b
);
7292 /* restart the period timer (if active) to handle new period expiry */
7293 if (runtime_enabled
&& cfs_b
->timer_active
) {
7294 /* force a reprogram */
7295 cfs_b
->timer_active
= 0;
7296 __start_cfs_bandwidth(cfs_b
);
7298 raw_spin_unlock_irq(&cfs_b
->lock
);
7300 for_each_possible_cpu(i
) {
7301 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7302 struct rq
*rq
= cfs_rq
->rq
;
7304 raw_spin_lock_irq(&rq
->lock
);
7305 cfs_rq
->runtime_enabled
= runtime_enabled
;
7306 cfs_rq
->runtime_remaining
= 0;
7308 if (cfs_rq
->throttled
)
7309 unthrottle_cfs_rq(cfs_rq
);
7310 raw_spin_unlock_irq(&rq
->lock
);
7313 mutex_unlock(&cfs_constraints_mutex
);
7318 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7322 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7323 if (cfs_quota_us
< 0)
7324 quota
= RUNTIME_INF
;
7326 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7328 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7331 long tg_get_cfs_quota(struct task_group
*tg
)
7335 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7338 quota_us
= tg
->cfs_bandwidth
.quota
;
7339 do_div(quota_us
, NSEC_PER_USEC
);
7344 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7348 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7349 quota
= tg
->cfs_bandwidth
.quota
;
7351 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7354 long tg_get_cfs_period(struct task_group
*tg
)
7358 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7359 do_div(cfs_period_us
, NSEC_PER_USEC
);
7361 return cfs_period_us
;
7364 static s64
cpu_cfs_quota_read_s64(struct cgroup
*cgrp
, struct cftype
*cft
)
7366 return tg_get_cfs_quota(cgroup_tg(cgrp
));
7369 static int cpu_cfs_quota_write_s64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7372 return tg_set_cfs_quota(cgroup_tg(cgrp
), cfs_quota_us
);
7375 static u64
cpu_cfs_period_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7377 return tg_get_cfs_period(cgroup_tg(cgrp
));
7380 static int cpu_cfs_period_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7383 return tg_set_cfs_period(cgroup_tg(cgrp
), cfs_period_us
);
7386 struct cfs_schedulable_data
{
7387 struct task_group
*tg
;
7392 * normalize group quota/period to be quota/max_period
7393 * note: units are usecs
7395 static u64
normalize_cfs_quota(struct task_group
*tg
,
7396 struct cfs_schedulable_data
*d
)
7404 period
= tg_get_cfs_period(tg
);
7405 quota
= tg_get_cfs_quota(tg
);
7408 /* note: these should typically be equivalent */
7409 if (quota
== RUNTIME_INF
|| quota
== -1)
7412 return to_ratio(period
, quota
);
7415 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7417 struct cfs_schedulable_data
*d
= data
;
7418 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7419 s64 quota
= 0, parent_quota
= -1;
7422 quota
= RUNTIME_INF
;
7424 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
7426 quota
= normalize_cfs_quota(tg
, d
);
7427 parent_quota
= parent_b
->hierarchal_quota
;
7430 * ensure max(child_quota) <= parent_quota, inherit when no
7433 if (quota
== RUNTIME_INF
)
7434 quota
= parent_quota
;
7435 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
7438 cfs_b
->hierarchal_quota
= quota
;
7443 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
7446 struct cfs_schedulable_data data
= {
7452 if (quota
!= RUNTIME_INF
) {
7453 do_div(data
.period
, NSEC_PER_USEC
);
7454 do_div(data
.quota
, NSEC_PER_USEC
);
7458 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
7464 static int cpu_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
7465 struct cgroup_map_cb
*cb
)
7467 struct task_group
*tg
= cgroup_tg(cgrp
);
7468 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7470 cb
->fill(cb
, "nr_periods", cfs_b
->nr_periods
);
7471 cb
->fill(cb
, "nr_throttled", cfs_b
->nr_throttled
);
7472 cb
->fill(cb
, "throttled_time", cfs_b
->throttled_time
);
7476 #endif /* CONFIG_CFS_BANDWIDTH */
7477 #endif /* CONFIG_FAIR_GROUP_SCHED */
7479 #ifdef CONFIG_RT_GROUP_SCHED
7480 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
7483 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
7486 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
7488 return sched_group_rt_runtime(cgroup_tg(cgrp
));
7491 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
7494 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
7497 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
7499 return sched_group_rt_period(cgroup_tg(cgrp
));
7501 #endif /* CONFIG_RT_GROUP_SCHED */
7503 static struct cftype cpu_files
[] = {
7504 #ifdef CONFIG_FAIR_GROUP_SCHED
7507 .read_u64
= cpu_shares_read_u64
,
7508 .write_u64
= cpu_shares_write_u64
,
7511 #ifdef CONFIG_CFS_BANDWIDTH
7513 .name
= "cfs_quota_us",
7514 .read_s64
= cpu_cfs_quota_read_s64
,
7515 .write_s64
= cpu_cfs_quota_write_s64
,
7518 .name
= "cfs_period_us",
7519 .read_u64
= cpu_cfs_period_read_u64
,
7520 .write_u64
= cpu_cfs_period_write_u64
,
7524 .read_map
= cpu_stats_show
,
7527 #ifdef CONFIG_RT_GROUP_SCHED
7529 .name
= "rt_runtime_us",
7530 .read_s64
= cpu_rt_runtime_read
,
7531 .write_s64
= cpu_rt_runtime_write
,
7534 .name
= "rt_period_us",
7535 .read_u64
= cpu_rt_period_read_uint
,
7536 .write_u64
= cpu_rt_period_write_uint
,
7542 struct cgroup_subsys cpu_cgroup_subsys
= {
7544 .css_alloc
= cpu_cgroup_css_alloc
,
7545 .css_free
= cpu_cgroup_css_free
,
7546 .css_online
= cpu_cgroup_css_online
,
7547 .css_offline
= cpu_cgroup_css_offline
,
7548 .can_attach
= cpu_cgroup_can_attach
,
7549 .attach
= cpu_cgroup_attach
,
7550 .exit
= cpu_cgroup_exit
,
7551 .subsys_id
= cpu_cgroup_subsys_id
,
7552 .base_cftypes
= cpu_files
,
7556 #endif /* CONFIG_CGROUP_SCHED */
7558 void dump_cpu_task(int cpu
)
7560 pr_info("Task dump for CPU %d:\n", cpu
);
7561 sched_show_task(cpu_curr(cpu
));