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.
374 * Its all a bit involved since we cannot program an hrt while holding the
375 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
378 * When we get rescheduled we reprogram the hrtick_timer outside of the
382 static void hrtick_clear(struct rq
*rq
)
384 if (hrtimer_active(&rq
->hrtick_timer
))
385 hrtimer_cancel(&rq
->hrtick_timer
);
389 * High-resolution timer tick.
390 * Runs from hardirq context with interrupts disabled.
392 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
394 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
396 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
398 raw_spin_lock(&rq
->lock
);
400 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
401 raw_spin_unlock(&rq
->lock
);
403 return HRTIMER_NORESTART
;
408 * called from hardirq (IPI) context
410 static void __hrtick_start(void *arg
)
414 raw_spin_lock(&rq
->lock
);
415 hrtimer_restart(&rq
->hrtick_timer
);
416 rq
->hrtick_csd_pending
= 0;
417 raw_spin_unlock(&rq
->lock
);
421 * Called to set the hrtick timer state.
423 * called with rq->lock held and irqs disabled
425 void hrtick_start(struct rq
*rq
, u64 delay
)
427 struct hrtimer
*timer
= &rq
->hrtick_timer
;
428 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
430 hrtimer_set_expires(timer
, time
);
432 if (rq
== this_rq()) {
433 hrtimer_restart(timer
);
434 } else if (!rq
->hrtick_csd_pending
) {
435 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
436 rq
->hrtick_csd_pending
= 1;
441 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
443 int cpu
= (int)(long)hcpu
;
446 case CPU_UP_CANCELED
:
447 case CPU_UP_CANCELED_FROZEN
:
448 case CPU_DOWN_PREPARE
:
449 case CPU_DOWN_PREPARE_FROZEN
:
451 case CPU_DEAD_FROZEN
:
452 hrtick_clear(cpu_rq(cpu
));
459 static __init
void init_hrtick(void)
461 hotcpu_notifier(hotplug_hrtick
, 0);
465 * Called to set the hrtick timer state.
467 * called with rq->lock held and irqs disabled
469 void hrtick_start(struct rq
*rq
, u64 delay
)
471 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
472 HRTIMER_MODE_REL_PINNED
, 0);
475 static inline void init_hrtick(void)
478 #endif /* CONFIG_SMP */
480 static void init_rq_hrtick(struct rq
*rq
)
483 rq
->hrtick_csd_pending
= 0;
485 rq
->hrtick_csd
.flags
= 0;
486 rq
->hrtick_csd
.func
= __hrtick_start
;
487 rq
->hrtick_csd
.info
= rq
;
490 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
491 rq
->hrtick_timer
.function
= hrtick
;
493 #else /* CONFIG_SCHED_HRTICK */
494 static inline void hrtick_clear(struct rq
*rq
)
498 static inline void init_rq_hrtick(struct rq
*rq
)
502 static inline void init_hrtick(void)
505 #endif /* CONFIG_SCHED_HRTICK */
508 * resched_task - mark a task 'to be rescheduled now'.
510 * On UP this means the setting of the need_resched flag, on SMP it
511 * might also involve a cross-CPU call to trigger the scheduler on
515 void resched_task(struct task_struct
*p
)
519 assert_raw_spin_locked(&task_rq(p
)->lock
);
521 if (test_tsk_need_resched(p
))
524 set_tsk_need_resched(p
);
527 if (cpu
== smp_processor_id())
530 /* NEED_RESCHED must be visible before we test polling */
532 if (!tsk_is_polling(p
))
533 smp_send_reschedule(cpu
);
536 void resched_cpu(int cpu
)
538 struct rq
*rq
= cpu_rq(cpu
);
541 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
543 resched_task(cpu_curr(cpu
));
544 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
547 #ifdef CONFIG_NO_HZ_COMMON
549 * In the semi idle case, use the nearest busy cpu for migrating timers
550 * from an idle cpu. This is good for power-savings.
552 * We don't do similar optimization for completely idle system, as
553 * selecting an idle cpu will add more delays to the timers than intended
554 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
556 int get_nohz_timer_target(void)
558 int cpu
= smp_processor_id();
560 struct sched_domain
*sd
;
563 for_each_domain(cpu
, sd
) {
564 for_each_cpu(i
, sched_domain_span(sd
)) {
576 * When add_timer_on() enqueues a timer into the timer wheel of an
577 * idle CPU then this timer might expire before the next timer event
578 * which is scheduled to wake up that CPU. In case of a completely
579 * idle system the next event might even be infinite time into the
580 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
581 * leaves the inner idle loop so the newly added timer is taken into
582 * account when the CPU goes back to idle and evaluates the timer
583 * wheel for the next timer event.
585 static void wake_up_idle_cpu(int cpu
)
587 struct rq
*rq
= cpu_rq(cpu
);
589 if (cpu
== smp_processor_id())
593 * This is safe, as this function is called with the timer
594 * wheel base lock of (cpu) held. When the CPU is on the way
595 * to idle and has not yet set rq->curr to idle then it will
596 * be serialized on the timer wheel base lock and take the new
597 * timer into account automatically.
599 if (rq
->curr
!= rq
->idle
)
603 * We can set TIF_RESCHED on the idle task of the other CPU
604 * lockless. The worst case is that the other CPU runs the
605 * idle task through an additional NOOP schedule()
607 set_tsk_need_resched(rq
->idle
);
609 /* NEED_RESCHED must be visible before we test polling */
611 if (!tsk_is_polling(rq
->idle
))
612 smp_send_reschedule(cpu
);
615 static bool wake_up_full_nohz_cpu(int cpu
)
617 if (tick_nohz_full_cpu(cpu
)) {
618 if (cpu
!= smp_processor_id() ||
619 tick_nohz_tick_stopped())
620 smp_send_reschedule(cpu
);
627 void wake_up_nohz_cpu(int cpu
)
629 if (!wake_up_full_nohz_cpu(cpu
))
630 wake_up_idle_cpu(cpu
);
633 static inline bool got_nohz_idle_kick(void)
635 int cpu
= smp_processor_id();
637 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
640 if (idle_cpu(cpu
) && !need_resched())
644 * We can't run Idle Load Balance on this CPU for this time so we
645 * cancel it and clear NOHZ_BALANCE_KICK
647 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
651 #else /* CONFIG_NO_HZ_COMMON */
653 static inline bool got_nohz_idle_kick(void)
658 #endif /* CONFIG_NO_HZ_COMMON */
660 #ifdef CONFIG_NO_HZ_FULL
661 bool sched_can_stop_tick(void)
667 /* Make sure rq->nr_running update is visible after the IPI */
670 /* More than one running task need preemption */
671 if (rq
->nr_running
> 1)
676 #endif /* CONFIG_NO_HZ_FULL */
678 void sched_avg_update(struct rq
*rq
)
680 s64 period
= sched_avg_period();
682 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
684 * Inline assembly required to prevent the compiler
685 * optimising this loop into a divmod call.
686 * See __iter_div_u64_rem() for another example of this.
688 asm("" : "+rm" (rq
->age_stamp
));
689 rq
->age_stamp
+= period
;
694 #else /* !CONFIG_SMP */
695 void resched_task(struct task_struct
*p
)
697 assert_raw_spin_locked(&task_rq(p
)->lock
);
698 set_tsk_need_resched(p
);
700 #endif /* CONFIG_SMP */
702 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
703 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
705 * Iterate task_group tree rooted at *from, calling @down when first entering a
706 * node and @up when leaving it for the final time.
708 * Caller must hold rcu_lock or sufficient equivalent.
710 int walk_tg_tree_from(struct task_group
*from
,
711 tg_visitor down
, tg_visitor up
, void *data
)
713 struct task_group
*parent
, *child
;
719 ret
= (*down
)(parent
, data
);
722 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
729 ret
= (*up
)(parent
, data
);
730 if (ret
|| parent
== from
)
734 parent
= parent
->parent
;
741 int tg_nop(struct task_group
*tg
, void *data
)
747 static void set_load_weight(struct task_struct
*p
)
749 int prio
= p
->static_prio
- MAX_RT_PRIO
;
750 struct load_weight
*load
= &p
->se
.load
;
753 * SCHED_IDLE tasks get minimal weight:
755 if (p
->policy
== SCHED_IDLE
) {
756 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
757 load
->inv_weight
= WMULT_IDLEPRIO
;
761 load
->weight
= scale_load(prio_to_weight
[prio
]);
762 load
->inv_weight
= prio_to_wmult
[prio
];
765 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
768 sched_info_queued(p
);
769 p
->sched_class
->enqueue_task(rq
, p
, flags
);
772 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
775 sched_info_dequeued(p
);
776 p
->sched_class
->dequeue_task(rq
, p
, flags
);
779 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
781 if (task_contributes_to_load(p
))
782 rq
->nr_uninterruptible
--;
784 enqueue_task(rq
, p
, flags
);
787 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
789 if (task_contributes_to_load(p
))
790 rq
->nr_uninterruptible
++;
792 dequeue_task(rq
, p
, flags
);
795 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
798 * In theory, the compile should just see 0 here, and optimize out the call
799 * to sched_rt_avg_update. But I don't trust it...
801 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
802 s64 steal
= 0, irq_delta
= 0;
804 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
805 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
808 * Since irq_time is only updated on {soft,}irq_exit, we might run into
809 * this case when a previous update_rq_clock() happened inside a
812 * When this happens, we stop ->clock_task and only update the
813 * prev_irq_time stamp to account for the part that fit, so that a next
814 * update will consume the rest. This ensures ->clock_task is
817 * It does however cause some slight miss-attribution of {soft,}irq
818 * time, a more accurate solution would be to update the irq_time using
819 * the current rq->clock timestamp, except that would require using
822 if (irq_delta
> delta
)
825 rq
->prev_irq_time
+= irq_delta
;
828 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
829 if (static_key_false((¶virt_steal_rq_enabled
))) {
832 steal
= paravirt_steal_clock(cpu_of(rq
));
833 steal
-= rq
->prev_steal_time_rq
;
835 if (unlikely(steal
> delta
))
838 st
= steal_ticks(steal
);
839 steal
= st
* TICK_NSEC
;
841 rq
->prev_steal_time_rq
+= steal
;
847 rq
->clock_task
+= delta
;
849 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
850 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
851 sched_rt_avg_update(rq
, irq_delta
+ steal
);
855 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
857 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
858 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
862 * Make it appear like a SCHED_FIFO task, its something
863 * userspace knows about and won't get confused about.
865 * Also, it will make PI more or less work without too
866 * much confusion -- but then, stop work should not
867 * rely on PI working anyway.
869 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
871 stop
->sched_class
= &stop_sched_class
;
874 cpu_rq(cpu
)->stop
= stop
;
878 * Reset it back to a normal scheduling class so that
879 * it can die in pieces.
881 old_stop
->sched_class
= &rt_sched_class
;
886 * __normal_prio - return the priority that is based on the static prio
888 static inline int __normal_prio(struct task_struct
*p
)
890 return p
->static_prio
;
894 * Calculate the expected normal priority: i.e. priority
895 * without taking RT-inheritance into account. Might be
896 * boosted by interactivity modifiers. Changes upon fork,
897 * setprio syscalls, and whenever the interactivity
898 * estimator recalculates.
900 static inline int normal_prio(struct task_struct
*p
)
904 if (task_has_rt_policy(p
))
905 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
907 prio
= __normal_prio(p
);
912 * Calculate the current priority, i.e. the priority
913 * taken into account by the scheduler. This value might
914 * be boosted by RT tasks, or might be boosted by
915 * interactivity modifiers. Will be RT if the task got
916 * RT-boosted. If not then it returns p->normal_prio.
918 static int effective_prio(struct task_struct
*p
)
920 p
->normal_prio
= normal_prio(p
);
922 * If we are RT tasks or we were boosted to RT priority,
923 * keep the priority unchanged. Otherwise, update priority
924 * to the normal priority:
926 if (!rt_prio(p
->prio
))
927 return p
->normal_prio
;
932 * task_curr - is this task currently executing on a CPU?
933 * @p: the task in question.
935 inline int task_curr(const struct task_struct
*p
)
937 return cpu_curr(task_cpu(p
)) == p
;
940 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
941 const struct sched_class
*prev_class
,
944 if (prev_class
!= p
->sched_class
) {
945 if (prev_class
->switched_from
)
946 prev_class
->switched_from(rq
, p
);
947 p
->sched_class
->switched_to(rq
, p
);
948 } else if (oldprio
!= p
->prio
)
949 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
952 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
954 const struct sched_class
*class;
956 if (p
->sched_class
== rq
->curr
->sched_class
) {
957 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
959 for_each_class(class) {
960 if (class == rq
->curr
->sched_class
)
962 if (class == p
->sched_class
) {
963 resched_task(rq
->curr
);
970 * A queue event has occurred, and we're going to schedule. In
971 * this case, we can save a useless back to back clock update.
973 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
974 rq
->skip_clock_update
= 1;
977 static ATOMIC_NOTIFIER_HEAD(task_migration_notifier
);
979 void register_task_migration_notifier(struct notifier_block
*n
)
981 atomic_notifier_chain_register(&task_migration_notifier
, n
);
985 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
987 #ifdef CONFIG_SCHED_DEBUG
989 * We should never call set_task_cpu() on a blocked task,
990 * ttwu() will sort out the placement.
992 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
993 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
995 #ifdef CONFIG_LOCKDEP
997 * The caller should hold either p->pi_lock or rq->lock, when changing
998 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1000 * sched_move_task() holds both and thus holding either pins the cgroup,
1003 * Furthermore, all task_rq users should acquire both locks, see
1006 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1007 lockdep_is_held(&task_rq(p
)->lock
)));
1011 trace_sched_migrate_task(p
, new_cpu
);
1013 if (task_cpu(p
) != new_cpu
) {
1014 struct task_migration_notifier tmn
;
1016 if (p
->sched_class
->migrate_task_rq
)
1017 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1018 p
->se
.nr_migrations
++;
1019 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1022 tmn
.from_cpu
= task_cpu(p
);
1023 tmn
.to_cpu
= new_cpu
;
1025 atomic_notifier_call_chain(&task_migration_notifier
, 0, &tmn
);
1028 __set_task_cpu(p
, new_cpu
);
1031 struct migration_arg
{
1032 struct task_struct
*task
;
1036 static int migration_cpu_stop(void *data
);
1039 * wait_task_inactive - wait for a thread to unschedule.
1041 * If @match_state is nonzero, it's the @p->state value just checked and
1042 * not expected to change. If it changes, i.e. @p might have woken up,
1043 * then return zero. When we succeed in waiting for @p to be off its CPU,
1044 * we return a positive number (its total switch count). If a second call
1045 * a short while later returns the same number, the caller can be sure that
1046 * @p has remained unscheduled the whole time.
1048 * The caller must ensure that the task *will* unschedule sometime soon,
1049 * else this function might spin for a *long* time. This function can't
1050 * be called with interrupts off, or it may introduce deadlock with
1051 * smp_call_function() if an IPI is sent by the same process we are
1052 * waiting to become inactive.
1054 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1056 unsigned long flags
;
1063 * We do the initial early heuristics without holding
1064 * any task-queue locks at all. We'll only try to get
1065 * the runqueue lock when things look like they will
1071 * If the task is actively running on another CPU
1072 * still, just relax and busy-wait without holding
1075 * NOTE! Since we don't hold any locks, it's not
1076 * even sure that "rq" stays as the right runqueue!
1077 * But we don't care, since "task_running()" will
1078 * return false if the runqueue has changed and p
1079 * is actually now running somewhere else!
1081 while (task_running(rq
, p
)) {
1082 if (match_state
&& unlikely(p
->state
!= match_state
))
1088 * Ok, time to look more closely! We need the rq
1089 * lock now, to be *sure*. If we're wrong, we'll
1090 * just go back and repeat.
1092 rq
= task_rq_lock(p
, &flags
);
1093 trace_sched_wait_task(p
);
1094 running
= task_running(rq
, p
);
1097 if (!match_state
|| p
->state
== match_state
)
1098 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1099 task_rq_unlock(rq
, p
, &flags
);
1102 * If it changed from the expected state, bail out now.
1104 if (unlikely(!ncsw
))
1108 * Was it really running after all now that we
1109 * checked with the proper locks actually held?
1111 * Oops. Go back and try again..
1113 if (unlikely(running
)) {
1119 * It's not enough that it's not actively running,
1120 * it must be off the runqueue _entirely_, and not
1123 * So if it was still runnable (but just not actively
1124 * running right now), it's preempted, and we should
1125 * yield - it could be a while.
1127 if (unlikely(on_rq
)) {
1128 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1130 set_current_state(TASK_UNINTERRUPTIBLE
);
1131 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1136 * Ahh, all good. It wasn't running, and it wasn't
1137 * runnable, which means that it will never become
1138 * running in the future either. We're all done!
1147 * kick_process - kick a running thread to enter/exit the kernel
1148 * @p: the to-be-kicked thread
1150 * Cause a process which is running on another CPU to enter
1151 * kernel-mode, without any delay. (to get signals handled.)
1153 * NOTE: this function doesn't have to take the runqueue lock,
1154 * because all it wants to ensure is that the remote task enters
1155 * the kernel. If the IPI races and the task has been migrated
1156 * to another CPU then no harm is done and the purpose has been
1159 void kick_process(struct task_struct
*p
)
1165 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1166 smp_send_reschedule(cpu
);
1169 EXPORT_SYMBOL_GPL(kick_process
);
1170 #endif /* CONFIG_SMP */
1174 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1176 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1178 int nid
= cpu_to_node(cpu
);
1179 const struct cpumask
*nodemask
= NULL
;
1180 enum { cpuset
, possible
, fail
} state
= cpuset
;
1184 * If the node that the cpu is on has been offlined, cpu_to_node()
1185 * will return -1. There is no cpu on the node, and we should
1186 * select the cpu on the other node.
1189 nodemask
= cpumask_of_node(nid
);
1191 /* Look for allowed, online CPU in same node. */
1192 for_each_cpu(dest_cpu
, nodemask
) {
1193 if (!cpu_online(dest_cpu
))
1195 if (!cpu_active(dest_cpu
))
1197 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1203 /* Any allowed, online CPU? */
1204 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1205 if (!cpu_online(dest_cpu
))
1207 if (!cpu_active(dest_cpu
))
1214 /* No more Mr. Nice Guy. */
1215 cpuset_cpus_allowed_fallback(p
);
1220 do_set_cpus_allowed(p
, cpu_possible_mask
);
1231 if (state
!= cpuset
) {
1233 * Don't tell them about moving exiting tasks or
1234 * kernel threads (both mm NULL), since they never
1237 if (p
->mm
&& printk_ratelimit()) {
1238 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1239 task_pid_nr(p
), p
->comm
, cpu
);
1247 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1250 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
1252 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
1255 * In order not to call set_task_cpu() on a blocking task we need
1256 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1259 * Since this is common to all placement strategies, this lives here.
1261 * [ this allows ->select_task() to simply return task_cpu(p) and
1262 * not worry about this generic constraint ]
1264 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1266 cpu
= select_fallback_rq(task_cpu(p
), p
);
1271 static void update_avg(u64
*avg
, u64 sample
)
1273 s64 diff
= sample
- *avg
;
1279 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1281 #ifdef CONFIG_SCHEDSTATS
1282 struct rq
*rq
= this_rq();
1285 int this_cpu
= smp_processor_id();
1287 if (cpu
== this_cpu
) {
1288 schedstat_inc(rq
, ttwu_local
);
1289 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1291 struct sched_domain
*sd
;
1293 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1295 for_each_domain(this_cpu
, sd
) {
1296 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1297 schedstat_inc(sd
, ttwu_wake_remote
);
1304 if (wake_flags
& WF_MIGRATED
)
1305 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1307 #endif /* CONFIG_SMP */
1309 schedstat_inc(rq
, ttwu_count
);
1310 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1312 if (wake_flags
& WF_SYNC
)
1313 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1315 #endif /* CONFIG_SCHEDSTATS */
1318 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1320 activate_task(rq
, p
, en_flags
);
1323 /* if a worker is waking up, notify workqueue */
1324 if (p
->flags
& PF_WQ_WORKER
)
1325 wq_worker_waking_up(p
, cpu_of(rq
));
1329 * Mark the task runnable and perform wakeup-preemption.
1332 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1334 check_preempt_curr(rq
, p
, wake_flags
);
1335 trace_sched_wakeup(p
, true);
1337 p
->state
= TASK_RUNNING
;
1339 if (p
->sched_class
->task_woken
)
1340 p
->sched_class
->task_woken(rq
, p
);
1342 if (rq
->idle_stamp
) {
1343 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1344 u64 max
= 2*sysctl_sched_migration_cost
;
1349 update_avg(&rq
->avg_idle
, delta
);
1356 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1359 if (p
->sched_contributes_to_load
)
1360 rq
->nr_uninterruptible
--;
1363 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1364 ttwu_do_wakeup(rq
, p
, wake_flags
);
1368 * Called in case the task @p isn't fully descheduled from its runqueue,
1369 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1370 * since all we need to do is flip p->state to TASK_RUNNING, since
1371 * the task is still ->on_rq.
1373 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1378 rq
= __task_rq_lock(p
);
1380 /* check_preempt_curr() may use rq clock */
1381 update_rq_clock(rq
);
1382 ttwu_do_wakeup(rq
, p
, wake_flags
);
1385 __task_rq_unlock(rq
);
1391 static void sched_ttwu_pending(void)
1393 struct rq
*rq
= this_rq();
1394 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1395 struct task_struct
*p
;
1397 raw_spin_lock(&rq
->lock
);
1400 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1401 llist
= llist_next(llist
);
1402 ttwu_do_activate(rq
, p
, 0);
1405 raw_spin_unlock(&rq
->lock
);
1408 void scheduler_ipi(void)
1410 if (llist_empty(&this_rq()->wake_list
)
1411 && !tick_nohz_full_cpu(smp_processor_id())
1412 && !got_nohz_idle_kick())
1416 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1417 * traditionally all their work was done from the interrupt return
1418 * path. Now that we actually do some work, we need to make sure
1421 * Some archs already do call them, luckily irq_enter/exit nest
1424 * Arguably we should visit all archs and update all handlers,
1425 * however a fair share of IPIs are still resched only so this would
1426 * somewhat pessimize the simple resched case.
1429 tick_nohz_full_check();
1430 sched_ttwu_pending();
1433 * Check if someone kicked us for doing the nohz idle load balance.
1435 if (unlikely(got_nohz_idle_kick())) {
1436 this_rq()->idle_balance
= 1;
1437 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1442 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1444 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
1445 smp_send_reschedule(cpu
);
1448 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1450 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1452 #endif /* CONFIG_SMP */
1454 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1456 struct rq
*rq
= cpu_rq(cpu
);
1458 #if defined(CONFIG_SMP)
1459 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1460 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1461 ttwu_queue_remote(p
, cpu
);
1466 raw_spin_lock(&rq
->lock
);
1467 ttwu_do_activate(rq
, p
, 0);
1468 raw_spin_unlock(&rq
->lock
);
1472 * try_to_wake_up - wake up a thread
1473 * @p: the thread to be awakened
1474 * @state: the mask of task states that can be woken
1475 * @wake_flags: wake modifier flags (WF_*)
1477 * Put it on the run-queue if it's not already there. The "current"
1478 * thread is always on the run-queue (except when the actual
1479 * re-schedule is in progress), and as such you're allowed to do
1480 * the simpler "current->state = TASK_RUNNING" to mark yourself
1481 * runnable without the overhead of this.
1483 * Returns %true if @p was woken up, %false if it was already running
1484 * or @state didn't match @p's state.
1487 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1489 unsigned long flags
;
1490 int cpu
, success
= 0;
1493 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1494 if (!(p
->state
& state
))
1497 success
= 1; /* we're going to change ->state */
1500 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1505 * If the owning (remote) cpu is still in the middle of schedule() with
1506 * this task as prev, wait until its done referencing the task.
1511 * Pairs with the smp_wmb() in finish_lock_switch().
1515 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1516 p
->state
= TASK_WAKING
;
1518 if (p
->sched_class
->task_waking
)
1519 p
->sched_class
->task_waking(p
);
1521 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
1522 if (task_cpu(p
) != cpu
) {
1523 wake_flags
|= WF_MIGRATED
;
1524 set_task_cpu(p
, cpu
);
1526 #endif /* CONFIG_SMP */
1530 ttwu_stat(p
, cpu
, wake_flags
);
1532 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1538 * try_to_wake_up_local - try to wake up a local task with rq lock held
1539 * @p: the thread to be awakened
1541 * Put @p on the run-queue if it's not already there. The caller must
1542 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1545 static void try_to_wake_up_local(struct task_struct
*p
)
1547 struct rq
*rq
= task_rq(p
);
1549 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1550 WARN_ON_ONCE(p
== current
))
1553 lockdep_assert_held(&rq
->lock
);
1555 if (!raw_spin_trylock(&p
->pi_lock
)) {
1556 raw_spin_unlock(&rq
->lock
);
1557 raw_spin_lock(&p
->pi_lock
);
1558 raw_spin_lock(&rq
->lock
);
1561 if (!(p
->state
& TASK_NORMAL
))
1565 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1567 ttwu_do_wakeup(rq
, p
, 0);
1568 ttwu_stat(p
, smp_processor_id(), 0);
1570 raw_spin_unlock(&p
->pi_lock
);
1574 * wake_up_process - Wake up a specific process
1575 * @p: The process to be woken up.
1577 * Attempt to wake up the nominated process and move it to the set of runnable
1578 * processes. Returns 1 if the process was woken up, 0 if it was already
1581 * It may be assumed that this function implies a write memory barrier before
1582 * changing the task state if and only if any tasks are woken up.
1584 int wake_up_process(struct task_struct
*p
)
1586 WARN_ON(task_is_stopped_or_traced(p
));
1587 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1589 EXPORT_SYMBOL(wake_up_process
);
1591 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1593 return try_to_wake_up(p
, state
, 0);
1597 * Perform scheduler related setup for a newly forked process p.
1598 * p is forked by current.
1600 * __sched_fork() is basic setup used by init_idle() too:
1602 static void __sched_fork(struct task_struct
*p
)
1607 p
->se
.exec_start
= 0;
1608 p
->se
.sum_exec_runtime
= 0;
1609 p
->se
.prev_sum_exec_runtime
= 0;
1610 p
->se
.nr_migrations
= 0;
1612 INIT_LIST_HEAD(&p
->se
.group_node
);
1615 * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
1616 * removed when useful for applications beyond shares distribution (e.g.
1619 #if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)
1620 p
->se
.avg
.runnable_avg_period
= 0;
1621 p
->se
.avg
.runnable_avg_sum
= 0;
1623 #ifdef CONFIG_SCHEDSTATS
1624 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1627 INIT_LIST_HEAD(&p
->rt
.run_list
);
1629 #ifdef CONFIG_PREEMPT_NOTIFIERS
1630 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1633 #ifdef CONFIG_NUMA_BALANCING
1634 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1635 p
->mm
->numa_next_scan
= jiffies
;
1636 p
->mm
->numa_next_reset
= jiffies
;
1637 p
->mm
->numa_scan_seq
= 0;
1640 p
->node_stamp
= 0ULL;
1641 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1642 p
->numa_migrate_seq
= p
->mm
? p
->mm
->numa_scan_seq
- 1 : 0;
1643 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1644 p
->numa_work
.next
= &p
->numa_work
;
1645 #endif /* CONFIG_NUMA_BALANCING */
1648 #ifdef CONFIG_NUMA_BALANCING
1649 #ifdef CONFIG_SCHED_DEBUG
1650 void set_numabalancing_state(bool enabled
)
1653 sched_feat_set("NUMA");
1655 sched_feat_set("NO_NUMA");
1658 __read_mostly
bool numabalancing_enabled
;
1660 void set_numabalancing_state(bool enabled
)
1662 numabalancing_enabled
= enabled
;
1664 #endif /* CONFIG_SCHED_DEBUG */
1665 #endif /* CONFIG_NUMA_BALANCING */
1668 * fork()/clone()-time setup:
1670 void sched_fork(struct task_struct
*p
)
1672 unsigned long flags
;
1673 int cpu
= get_cpu();
1677 * We mark the process as running here. This guarantees that
1678 * nobody will actually run it, and a signal or other external
1679 * event cannot wake it up and insert it on the runqueue either.
1681 p
->state
= TASK_RUNNING
;
1684 * Make sure we do not leak PI boosting priority to the child.
1686 p
->prio
= current
->normal_prio
;
1689 * Revert to default priority/policy on fork if requested.
1691 if (unlikely(p
->sched_reset_on_fork
)) {
1692 if (task_has_rt_policy(p
)) {
1693 p
->policy
= SCHED_NORMAL
;
1694 p
->static_prio
= NICE_TO_PRIO(0);
1696 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1697 p
->static_prio
= NICE_TO_PRIO(0);
1699 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1703 * We don't need the reset flag anymore after the fork. It has
1704 * fulfilled its duty:
1706 p
->sched_reset_on_fork
= 0;
1709 if (!rt_prio(p
->prio
))
1710 p
->sched_class
= &fair_sched_class
;
1712 if (p
->sched_class
->task_fork
)
1713 p
->sched_class
->task_fork(p
);
1716 * The child is not yet in the pid-hash so no cgroup attach races,
1717 * and the cgroup is pinned to this child due to cgroup_fork()
1718 * is ran before sched_fork().
1720 * Silence PROVE_RCU.
1722 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1723 set_task_cpu(p
, cpu
);
1724 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1726 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1727 if (likely(sched_info_on()))
1728 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1730 #if defined(CONFIG_SMP)
1733 #ifdef CONFIG_PREEMPT_COUNT
1734 /* Want to start with kernel preemption disabled. */
1735 task_thread_info(p
)->preempt_count
= 1;
1738 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1745 * wake_up_new_task - wake up a newly created task for the first time.
1747 * This function will do some initial scheduler statistics housekeeping
1748 * that must be done for every newly created context, then puts the task
1749 * on the runqueue and wakes it.
1751 void wake_up_new_task(struct task_struct
*p
)
1753 unsigned long flags
;
1756 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1759 * Fork balancing, do it here and not earlier because:
1760 * - cpus_allowed can change in the fork path
1761 * - any previously selected cpu might disappear through hotplug
1763 set_task_cpu(p
, select_task_rq(p
, SD_BALANCE_FORK
, 0));
1766 rq
= __task_rq_lock(p
);
1767 activate_task(rq
, p
, 0);
1769 trace_sched_wakeup_new(p
, true);
1770 check_preempt_curr(rq
, p
, WF_FORK
);
1772 if (p
->sched_class
->task_woken
)
1773 p
->sched_class
->task_woken(rq
, p
);
1775 task_rq_unlock(rq
, p
, &flags
);
1778 #ifdef CONFIG_PREEMPT_NOTIFIERS
1781 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1782 * @notifier: notifier struct to register
1784 void preempt_notifier_register(struct preempt_notifier
*notifier
)
1786 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
1788 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
1791 * preempt_notifier_unregister - no longer interested in preemption notifications
1792 * @notifier: notifier struct to unregister
1794 * This is safe to call from within a preemption notifier.
1796 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
1798 hlist_del(¬ifier
->link
);
1800 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
1802 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1804 struct preempt_notifier
*notifier
;
1806 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
1807 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
1811 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1812 struct task_struct
*next
)
1814 struct preempt_notifier
*notifier
;
1816 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
1817 notifier
->ops
->sched_out(notifier
, next
);
1820 #else /* !CONFIG_PREEMPT_NOTIFIERS */
1822 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1827 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1828 struct task_struct
*next
)
1832 #endif /* CONFIG_PREEMPT_NOTIFIERS */
1835 * prepare_task_switch - prepare to switch tasks
1836 * @rq: the runqueue preparing to switch
1837 * @prev: the current task that is being switched out
1838 * @next: the task we are going to switch to.
1840 * This is called with the rq lock held and interrupts off. It must
1841 * be paired with a subsequent finish_task_switch after the context
1844 * prepare_task_switch sets up locking and calls architecture specific
1848 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
1849 struct task_struct
*next
)
1851 trace_sched_switch(prev
, next
);
1852 sched_info_switch(prev
, next
);
1853 perf_event_task_sched_out(prev
, next
);
1854 fire_sched_out_preempt_notifiers(prev
, next
);
1855 prepare_lock_switch(rq
, next
);
1856 prepare_arch_switch(next
);
1860 * finish_task_switch - clean up after a task-switch
1861 * @rq: runqueue associated with task-switch
1862 * @prev: the thread we just switched away from.
1864 * finish_task_switch must be called after the context switch, paired
1865 * with a prepare_task_switch call before the context switch.
1866 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1867 * and do any other architecture-specific cleanup actions.
1869 * Note that we may have delayed dropping an mm in context_switch(). If
1870 * so, we finish that here outside of the runqueue lock. (Doing it
1871 * with the lock held can cause deadlocks; see schedule() for
1874 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
1875 __releases(rq
->lock
)
1877 struct mm_struct
*mm
= rq
->prev_mm
;
1883 * A task struct has one reference for the use as "current".
1884 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1885 * schedule one last time. The schedule call will never return, and
1886 * the scheduled task must drop that reference.
1887 * The test for TASK_DEAD must occur while the runqueue locks are
1888 * still held, otherwise prev could be scheduled on another cpu, die
1889 * there before we look at prev->state, and then the reference would
1891 * Manfred Spraul <manfred@colorfullife.com>
1893 prev_state
= prev
->state
;
1894 vtime_task_switch(prev
);
1895 finish_arch_switch(prev
);
1896 perf_event_task_sched_in(prev
, current
);
1897 finish_lock_switch(rq
, prev
);
1898 finish_arch_post_lock_switch();
1900 fire_sched_in_preempt_notifiers(current
);
1903 if (unlikely(prev_state
== TASK_DEAD
)) {
1905 * Remove function-return probe instances associated with this
1906 * task and put them back on the free list.
1908 kprobe_flush_task(prev
);
1909 put_task_struct(prev
);
1912 tick_nohz_task_switch(current
);
1917 /* assumes rq->lock is held */
1918 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
1920 if (prev
->sched_class
->pre_schedule
)
1921 prev
->sched_class
->pre_schedule(rq
, prev
);
1924 /* rq->lock is NOT held, but preemption is disabled */
1925 static inline void post_schedule(struct rq
*rq
)
1927 if (rq
->post_schedule
) {
1928 unsigned long flags
;
1930 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1931 if (rq
->curr
->sched_class
->post_schedule
)
1932 rq
->curr
->sched_class
->post_schedule(rq
);
1933 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1935 rq
->post_schedule
= 0;
1941 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
1945 static inline void post_schedule(struct rq
*rq
)
1952 * schedule_tail - first thing a freshly forked thread must call.
1953 * @prev: the thread we just switched away from.
1955 asmlinkage
void schedule_tail(struct task_struct
*prev
)
1956 __releases(rq
->lock
)
1958 struct rq
*rq
= this_rq();
1960 finish_task_switch(rq
, prev
);
1963 * FIXME: do we need to worry about rq being invalidated by the
1968 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
1969 /* In this case, finish_task_switch does not reenable preemption */
1972 if (current
->set_child_tid
)
1973 put_user(task_pid_vnr(current
), current
->set_child_tid
);
1977 * context_switch - switch to the new MM and the new
1978 * thread's register state.
1981 context_switch(struct rq
*rq
, struct task_struct
*prev
,
1982 struct task_struct
*next
)
1984 struct mm_struct
*mm
, *oldmm
;
1986 prepare_task_switch(rq
, prev
, next
);
1989 oldmm
= prev
->active_mm
;
1991 * For paravirt, this is coupled with an exit in switch_to to
1992 * combine the page table reload and the switch backend into
1995 arch_start_context_switch(prev
);
1998 next
->active_mm
= oldmm
;
1999 atomic_inc(&oldmm
->mm_count
);
2000 enter_lazy_tlb(oldmm
, next
);
2002 switch_mm(oldmm
, mm
, next
);
2005 prev
->active_mm
= NULL
;
2006 rq
->prev_mm
= oldmm
;
2009 * Since the runqueue lock will be released by the next
2010 * task (which is an invalid locking op but in the case
2011 * of the scheduler it's an obvious special-case), so we
2012 * do an early lockdep release here:
2014 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2015 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2018 context_tracking_task_switch(prev
, next
);
2019 /* Here we just switch the register state and the stack. */
2020 switch_to(prev
, next
, prev
);
2024 * this_rq must be evaluated again because prev may have moved
2025 * CPUs since it called schedule(), thus the 'rq' on its stack
2026 * frame will be invalid.
2028 finish_task_switch(this_rq(), prev
);
2032 * nr_running and nr_context_switches:
2034 * externally visible scheduler statistics: current number of runnable
2035 * threads, total number of context switches performed since bootup.
2037 unsigned long nr_running(void)
2039 unsigned long i
, sum
= 0;
2041 for_each_online_cpu(i
)
2042 sum
+= cpu_rq(i
)->nr_running
;
2047 unsigned long long nr_context_switches(void)
2050 unsigned long long sum
= 0;
2052 for_each_possible_cpu(i
)
2053 sum
+= cpu_rq(i
)->nr_switches
;
2058 unsigned long nr_iowait(void)
2060 unsigned long i
, sum
= 0;
2062 for_each_possible_cpu(i
)
2063 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2068 unsigned long nr_iowait_cpu(int cpu
)
2070 struct rq
*this = cpu_rq(cpu
);
2071 return atomic_read(&this->nr_iowait
);
2077 * sched_exec - execve() is a valuable balancing opportunity, because at
2078 * this point the task has the smallest effective memory and cache footprint.
2080 void sched_exec(void)
2082 struct task_struct
*p
= current
;
2083 unsigned long flags
;
2086 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2087 dest_cpu
= p
->sched_class
->select_task_rq(p
, SD_BALANCE_EXEC
, 0);
2088 if (dest_cpu
== smp_processor_id())
2091 if (likely(cpu_active(dest_cpu
))) {
2092 struct migration_arg arg
= { p
, dest_cpu
};
2094 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2095 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2099 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2104 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2105 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2107 EXPORT_PER_CPU_SYMBOL(kstat
);
2108 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2111 * Return any ns on the sched_clock that have not yet been accounted in
2112 * @p in case that task is currently running.
2114 * Called with task_rq_lock() held on @rq.
2116 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2120 if (task_current(rq
, p
)) {
2121 update_rq_clock(rq
);
2122 ns
= rq_clock_task(rq
) - p
->se
.exec_start
;
2130 unsigned long long task_delta_exec(struct task_struct
*p
)
2132 unsigned long flags
;
2136 rq
= task_rq_lock(p
, &flags
);
2137 ns
= do_task_delta_exec(p
, rq
);
2138 task_rq_unlock(rq
, p
, &flags
);
2144 * Return accounted runtime for the task.
2145 * In case the task is currently running, return the runtime plus current's
2146 * pending runtime that have not been accounted yet.
2148 unsigned long long task_sched_runtime(struct task_struct
*p
)
2150 unsigned long flags
;
2154 rq
= task_rq_lock(p
, &flags
);
2155 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2156 task_rq_unlock(rq
, p
, &flags
);
2162 * This function gets called by the timer code, with HZ frequency.
2163 * We call it with interrupts disabled.
2165 void scheduler_tick(void)
2167 int cpu
= smp_processor_id();
2168 struct rq
*rq
= cpu_rq(cpu
);
2169 struct task_struct
*curr
= rq
->curr
;
2173 raw_spin_lock(&rq
->lock
);
2174 update_rq_clock(rq
);
2175 update_cpu_load_active(rq
);
2176 curr
->sched_class
->task_tick(rq
, curr
, 0);
2177 raw_spin_unlock(&rq
->lock
);
2179 perf_event_task_tick();
2182 rq
->idle_balance
= idle_cpu(cpu
);
2183 trigger_load_balance(rq
, cpu
);
2185 rq_last_tick_reset(rq
);
2188 #ifdef CONFIG_NO_HZ_FULL
2190 * scheduler_tick_max_deferment
2192 * Keep at least one tick per second when a single
2193 * active task is running because the scheduler doesn't
2194 * yet completely support full dynticks environment.
2196 * This makes sure that uptime, CFS vruntime, load
2197 * balancing, etc... continue to move forward, even
2198 * with a very low granularity.
2200 u64
scheduler_tick_max_deferment(void)
2202 struct rq
*rq
= this_rq();
2203 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2205 next
= rq
->last_sched_tick
+ HZ
;
2207 if (time_before_eq(next
, now
))
2210 return jiffies_to_usecs(next
- now
) * NSEC_PER_USEC
;
2214 notrace
unsigned long get_parent_ip(unsigned long addr
)
2216 if (in_lock_functions(addr
)) {
2217 addr
= CALLER_ADDR2
;
2218 if (in_lock_functions(addr
))
2219 addr
= CALLER_ADDR3
;
2224 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2225 defined(CONFIG_PREEMPT_TRACER))
2227 void __kprobes
add_preempt_count(int val
)
2229 #ifdef CONFIG_DEBUG_PREEMPT
2233 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2236 preempt_count() += val
;
2237 #ifdef CONFIG_DEBUG_PREEMPT
2239 * Spinlock count overflowing soon?
2241 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2244 if (preempt_count() == val
)
2245 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2247 EXPORT_SYMBOL(add_preempt_count
);
2249 void __kprobes
sub_preempt_count(int val
)
2251 #ifdef CONFIG_DEBUG_PREEMPT
2255 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2258 * Is the spinlock portion underflowing?
2260 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2261 !(preempt_count() & PREEMPT_MASK
)))
2265 if (preempt_count() == val
)
2266 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2267 preempt_count() -= val
;
2269 EXPORT_SYMBOL(sub_preempt_count
);
2274 * Print scheduling while atomic bug:
2276 static noinline
void __schedule_bug(struct task_struct
*prev
)
2278 if (oops_in_progress
)
2281 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2282 prev
->comm
, prev
->pid
, preempt_count());
2284 debug_show_held_locks(prev
);
2286 if (irqs_disabled())
2287 print_irqtrace_events(prev
);
2289 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2293 * Various schedule()-time debugging checks and statistics:
2295 static inline void schedule_debug(struct task_struct
*prev
)
2298 * Test if we are atomic. Since do_exit() needs to call into
2299 * schedule() atomically, we ignore that path for now.
2300 * Otherwise, whine if we are scheduling when we should not be.
2302 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
2303 __schedule_bug(prev
);
2306 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2308 schedstat_inc(this_rq(), sched_count
);
2311 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
2313 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
2314 update_rq_clock(rq
);
2315 prev
->sched_class
->put_prev_task(rq
, prev
);
2319 * Pick up the highest-prio task:
2321 static inline struct task_struct
*
2322 pick_next_task(struct rq
*rq
)
2324 const struct sched_class
*class;
2325 struct task_struct
*p
;
2328 * Optimization: we know that if all tasks are in
2329 * the fair class we can call that function directly:
2331 if (likely(rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2332 p
= fair_sched_class
.pick_next_task(rq
);
2337 for_each_class(class) {
2338 p
= class->pick_next_task(rq
);
2343 BUG(); /* the idle class will always have a runnable task */
2347 * __schedule() is the main scheduler function.
2349 * The main means of driving the scheduler and thus entering this function are:
2351 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2353 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2354 * paths. For example, see arch/x86/entry_64.S.
2356 * To drive preemption between tasks, the scheduler sets the flag in timer
2357 * interrupt handler scheduler_tick().
2359 * 3. Wakeups don't really cause entry into schedule(). They add a
2360 * task to the run-queue and that's it.
2362 * Now, if the new task added to the run-queue preempts the current
2363 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2364 * called on the nearest possible occasion:
2366 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2368 * - in syscall or exception context, at the next outmost
2369 * preempt_enable(). (this might be as soon as the wake_up()'s
2372 * - in IRQ context, return from interrupt-handler to
2373 * preemptible context
2375 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2378 * - cond_resched() call
2379 * - explicit schedule() call
2380 * - return from syscall or exception to user-space
2381 * - return from interrupt-handler to user-space
2383 static void __sched
__schedule(void)
2385 struct task_struct
*prev
, *next
;
2386 unsigned long *switch_count
;
2392 cpu
= smp_processor_id();
2394 rcu_note_context_switch(cpu
);
2397 schedule_debug(prev
);
2399 if (sched_feat(HRTICK
))
2402 raw_spin_lock_irq(&rq
->lock
);
2404 switch_count
= &prev
->nivcsw
;
2405 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2406 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2407 prev
->state
= TASK_RUNNING
;
2409 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2413 * If a worker went to sleep, notify and ask workqueue
2414 * whether it wants to wake up a task to maintain
2417 if (prev
->flags
& PF_WQ_WORKER
) {
2418 struct task_struct
*to_wakeup
;
2420 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2422 try_to_wake_up_local(to_wakeup
);
2425 switch_count
= &prev
->nvcsw
;
2428 pre_schedule(rq
, prev
);
2430 if (unlikely(!rq
->nr_running
))
2431 idle_balance(cpu
, rq
);
2433 put_prev_task(rq
, prev
);
2434 next
= pick_next_task(rq
);
2435 clear_tsk_need_resched(prev
);
2436 rq
->skip_clock_update
= 0;
2438 if (likely(prev
!= next
)) {
2443 context_switch(rq
, prev
, next
); /* unlocks the rq */
2445 * The context switch have flipped the stack from under us
2446 * and restored the local variables which were saved when
2447 * this task called schedule() in the past. prev == current
2448 * is still correct, but it can be moved to another cpu/rq.
2450 cpu
= smp_processor_id();
2453 raw_spin_unlock_irq(&rq
->lock
);
2457 sched_preempt_enable_no_resched();
2462 static inline void sched_submit_work(struct task_struct
*tsk
)
2464 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2467 * If we are going to sleep and we have plugged IO queued,
2468 * make sure to submit it to avoid deadlocks.
2470 if (blk_needs_flush_plug(tsk
))
2471 blk_schedule_flush_plug(tsk
);
2474 asmlinkage
void __sched
schedule(void)
2476 struct task_struct
*tsk
= current
;
2478 sched_submit_work(tsk
);
2481 EXPORT_SYMBOL(schedule
);
2483 #ifdef CONFIG_CONTEXT_TRACKING
2484 asmlinkage
void __sched
schedule_user(void)
2487 * If we come here after a random call to set_need_resched(),
2488 * or we have been woken up remotely but the IPI has not yet arrived,
2489 * we haven't yet exited the RCU idle mode. Do it here manually until
2490 * we find a better solution.
2499 * schedule_preempt_disabled - called with preemption disabled
2501 * Returns with preemption disabled. Note: preempt_count must be 1
2503 void __sched
schedule_preempt_disabled(void)
2505 sched_preempt_enable_no_resched();
2510 #ifdef CONFIG_PREEMPT
2512 * this is the entry point to schedule() from in-kernel preemption
2513 * off of preempt_enable. Kernel preemptions off return from interrupt
2514 * occur there and call schedule directly.
2516 asmlinkage
void __sched notrace
preempt_schedule(void)
2518 struct thread_info
*ti
= current_thread_info();
2521 * If there is a non-zero preempt_count or interrupts are disabled,
2522 * we do not want to preempt the current task. Just return..
2524 if (likely(ti
->preempt_count
|| irqs_disabled()))
2528 add_preempt_count_notrace(PREEMPT_ACTIVE
);
2530 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
2533 * Check again in case we missed a preemption opportunity
2534 * between schedule and now.
2537 } while (need_resched());
2539 EXPORT_SYMBOL(preempt_schedule
);
2542 * this is the entry point to schedule() from kernel preemption
2543 * off of irq context.
2544 * Note, that this is called and return with irqs disabled. This will
2545 * protect us against recursive calling from irq.
2547 asmlinkage
void __sched
preempt_schedule_irq(void)
2549 struct thread_info
*ti
= current_thread_info();
2550 enum ctx_state prev_state
;
2552 /* Catch callers which need to be fixed */
2553 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
2555 prev_state
= exception_enter();
2558 add_preempt_count(PREEMPT_ACTIVE
);
2561 local_irq_disable();
2562 sub_preempt_count(PREEMPT_ACTIVE
);
2565 * Check again in case we missed a preemption opportunity
2566 * between schedule and now.
2569 } while (need_resched());
2571 exception_exit(prev_state
);
2574 #endif /* CONFIG_PREEMPT */
2576 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2579 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2581 EXPORT_SYMBOL(default_wake_function
);
2584 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
2585 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
2586 * number) then we wake all the non-exclusive tasks and one exclusive task.
2588 * There are circumstances in which we can try to wake a task which has already
2589 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
2590 * zero in this (rare) case, and we handle it by continuing to scan the queue.
2592 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
2593 int nr_exclusive
, int wake_flags
, void *key
)
2595 wait_queue_t
*curr
, *next
;
2597 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
2598 unsigned flags
= curr
->flags
;
2600 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
2601 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
2607 * __wake_up - wake up threads blocked on a waitqueue.
2609 * @mode: which threads
2610 * @nr_exclusive: how many wake-one or wake-many threads to wake up
2611 * @key: is directly passed to the wakeup function
2613 * It may be assumed that this function implies a write memory barrier before
2614 * changing the task state if and only if any tasks are woken up.
2616 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
2617 int nr_exclusive
, void *key
)
2619 unsigned long flags
;
2621 spin_lock_irqsave(&q
->lock
, flags
);
2622 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
2623 spin_unlock_irqrestore(&q
->lock
, flags
);
2625 EXPORT_SYMBOL(__wake_up
);
2628 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
2630 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
, int nr
)
2632 __wake_up_common(q
, mode
, nr
, 0, NULL
);
2634 EXPORT_SYMBOL_GPL(__wake_up_locked
);
2636 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
2638 __wake_up_common(q
, mode
, 1, 0, key
);
2640 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
2643 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
2645 * @mode: which threads
2646 * @nr_exclusive: how many wake-one or wake-many threads to wake up
2647 * @key: opaque value to be passed to wakeup targets
2649 * The sync wakeup differs that the waker knows that it will schedule
2650 * away soon, so while the target thread will be woken up, it will not
2651 * be migrated to another CPU - ie. the two threads are 'synchronized'
2652 * with each other. This can prevent needless bouncing between CPUs.
2654 * On UP it can prevent extra preemption.
2656 * It may be assumed that this function implies a write memory barrier before
2657 * changing the task state if and only if any tasks are woken up.
2659 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
2660 int nr_exclusive
, void *key
)
2662 unsigned long flags
;
2663 int wake_flags
= WF_SYNC
;
2668 if (unlikely(!nr_exclusive
))
2671 spin_lock_irqsave(&q
->lock
, flags
);
2672 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
2673 spin_unlock_irqrestore(&q
->lock
, flags
);
2675 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
2678 * __wake_up_sync - see __wake_up_sync_key()
2680 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
2682 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
2684 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
2687 * complete: - signals a single thread waiting on this completion
2688 * @x: holds the state of this particular completion
2690 * This will wake up a single thread waiting on this completion. Threads will be
2691 * awakened in the same order in which they were queued.
2693 * See also complete_all(), wait_for_completion() and related routines.
2695 * It may be assumed that this function implies a write memory barrier before
2696 * changing the task state if and only if any tasks are woken up.
2698 void complete(struct completion
*x
)
2700 unsigned long flags
;
2702 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2704 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
2705 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2707 EXPORT_SYMBOL(complete
);
2710 * complete_all: - signals all threads waiting on this completion
2711 * @x: holds the state of this particular completion
2713 * This will wake up all threads waiting on this particular completion event.
2715 * It may be assumed that this function implies a write memory barrier before
2716 * changing the task state if and only if any tasks are woken up.
2718 void complete_all(struct completion
*x
)
2720 unsigned long flags
;
2722 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2723 x
->done
+= UINT_MAX
/2;
2724 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
2725 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2727 EXPORT_SYMBOL(complete_all
);
2729 static inline long __sched
2730 do_wait_for_common(struct completion
*x
,
2731 long (*action
)(long), long timeout
, int state
)
2734 DECLARE_WAITQUEUE(wait
, current
);
2736 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
2738 if (signal_pending_state(state
, current
)) {
2739 timeout
= -ERESTARTSYS
;
2742 __set_current_state(state
);
2743 spin_unlock_irq(&x
->wait
.lock
);
2744 timeout
= action(timeout
);
2745 spin_lock_irq(&x
->wait
.lock
);
2746 } while (!x
->done
&& timeout
);
2747 __remove_wait_queue(&x
->wait
, &wait
);
2752 return timeout
?: 1;
2755 static inline long __sched
2756 __wait_for_common(struct completion
*x
,
2757 long (*action
)(long), long timeout
, int state
)
2761 spin_lock_irq(&x
->wait
.lock
);
2762 timeout
= do_wait_for_common(x
, action
, timeout
, state
);
2763 spin_unlock_irq(&x
->wait
.lock
);
2768 wait_for_common(struct completion
*x
, long timeout
, int state
)
2770 return __wait_for_common(x
, schedule_timeout
, timeout
, state
);
2774 wait_for_common_io(struct completion
*x
, long timeout
, int state
)
2776 return __wait_for_common(x
, io_schedule_timeout
, timeout
, state
);
2780 * wait_for_completion: - waits for completion of a task
2781 * @x: holds the state of this particular completion
2783 * This waits to be signaled for completion of a specific task. It is NOT
2784 * interruptible and there is no timeout.
2786 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
2787 * and interrupt capability. Also see complete().
2789 void __sched
wait_for_completion(struct completion
*x
)
2791 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
2793 EXPORT_SYMBOL(wait_for_completion
);
2796 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
2797 * @x: holds the state of this particular completion
2798 * @timeout: timeout value in jiffies
2800 * This waits for either a completion of a specific task to be signaled or for a
2801 * specified timeout to expire. The timeout is in jiffies. It is not
2804 * The return value is 0 if timed out, and positive (at least 1, or number of
2805 * jiffies left till timeout) if completed.
2807 unsigned long __sched
2808 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
2810 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
2812 EXPORT_SYMBOL(wait_for_completion_timeout
);
2815 * wait_for_completion_io: - waits for completion of a task
2816 * @x: holds the state of this particular completion
2818 * This waits to be signaled for completion of a specific task. It is NOT
2819 * interruptible and there is no timeout. The caller is accounted as waiting
2822 void __sched
wait_for_completion_io(struct completion
*x
)
2824 wait_for_common_io(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
2826 EXPORT_SYMBOL(wait_for_completion_io
);
2829 * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout)
2830 * @x: holds the state of this particular completion
2831 * @timeout: timeout value in jiffies
2833 * This waits for either a completion of a specific task to be signaled or for a
2834 * specified timeout to expire. The timeout is in jiffies. It is not
2835 * interruptible. The caller is accounted as waiting for IO.
2837 * The return value is 0 if timed out, and positive (at least 1, or number of
2838 * jiffies left till timeout) if completed.
2840 unsigned long __sched
2841 wait_for_completion_io_timeout(struct completion
*x
, unsigned long timeout
)
2843 return wait_for_common_io(x
, timeout
, TASK_UNINTERRUPTIBLE
);
2845 EXPORT_SYMBOL(wait_for_completion_io_timeout
);
2848 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
2849 * @x: holds the state of this particular completion
2851 * This waits for completion of a specific task to be signaled. It is
2854 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
2856 int __sched
wait_for_completion_interruptible(struct completion
*x
)
2858 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
2859 if (t
== -ERESTARTSYS
)
2863 EXPORT_SYMBOL(wait_for_completion_interruptible
);
2866 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
2867 * @x: holds the state of this particular completion
2868 * @timeout: timeout value in jiffies
2870 * This waits for either a completion of a specific task to be signaled or for a
2871 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
2873 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
2874 * positive (at least 1, or number of jiffies left till timeout) if completed.
2877 wait_for_completion_interruptible_timeout(struct completion
*x
,
2878 unsigned long timeout
)
2880 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
2882 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
2885 * wait_for_completion_killable: - waits for completion of a task (killable)
2886 * @x: holds the state of this particular completion
2888 * This waits to be signaled for completion of a specific task. It can be
2889 * interrupted by a kill signal.
2891 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
2893 int __sched
wait_for_completion_killable(struct completion
*x
)
2895 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
2896 if (t
== -ERESTARTSYS
)
2900 EXPORT_SYMBOL(wait_for_completion_killable
);
2903 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
2904 * @x: holds the state of this particular completion
2905 * @timeout: timeout value in jiffies
2907 * This waits for either a completion of a specific task to be
2908 * signaled or for a specified timeout to expire. It can be
2909 * interrupted by a kill signal. The timeout is in jiffies.
2911 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
2912 * positive (at least 1, or number of jiffies left till timeout) if completed.
2915 wait_for_completion_killable_timeout(struct completion
*x
,
2916 unsigned long timeout
)
2918 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
2920 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
2923 * try_wait_for_completion - try to decrement a completion without blocking
2924 * @x: completion structure
2926 * Returns: 0 if a decrement cannot be done without blocking
2927 * 1 if a decrement succeeded.
2929 * If a completion is being used as a counting completion,
2930 * attempt to decrement the counter without blocking. This
2931 * enables us to avoid waiting if the resource the completion
2932 * is protecting is not available.
2934 bool try_wait_for_completion(struct completion
*x
)
2936 unsigned long flags
;
2939 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2944 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2947 EXPORT_SYMBOL(try_wait_for_completion
);
2950 * completion_done - Test to see if a completion has any waiters
2951 * @x: completion structure
2953 * Returns: 0 if there are waiters (wait_for_completion() in progress)
2954 * 1 if there are no waiters.
2957 bool completion_done(struct completion
*x
)
2959 unsigned long flags
;
2962 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2965 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2968 EXPORT_SYMBOL(completion_done
);
2971 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
2973 unsigned long flags
;
2976 init_waitqueue_entry(&wait
, current
);
2978 __set_current_state(state
);
2980 spin_lock_irqsave(&q
->lock
, flags
);
2981 __add_wait_queue(q
, &wait
);
2982 spin_unlock(&q
->lock
);
2983 timeout
= schedule_timeout(timeout
);
2984 spin_lock_irq(&q
->lock
);
2985 __remove_wait_queue(q
, &wait
);
2986 spin_unlock_irqrestore(&q
->lock
, flags
);
2991 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
2993 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
2995 EXPORT_SYMBOL(interruptible_sleep_on
);
2998 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3000 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
3002 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
3004 void __sched
sleep_on(wait_queue_head_t
*q
)
3006 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3008 EXPORT_SYMBOL(sleep_on
);
3010 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3012 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
3014 EXPORT_SYMBOL(sleep_on_timeout
);
3016 #ifdef CONFIG_RT_MUTEXES
3019 * rt_mutex_setprio - set the current priority of a task
3021 * @prio: prio value (kernel-internal form)
3023 * This function changes the 'effective' priority of a task. It does
3024 * not touch ->normal_prio like __setscheduler().
3026 * Used by the rt_mutex code to implement priority inheritance logic.
3028 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
3030 int oldprio
, on_rq
, running
;
3032 const struct sched_class
*prev_class
;
3034 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
3036 rq
= __task_rq_lock(p
);
3039 * Idle task boosting is a nono in general. There is one
3040 * exception, when PREEMPT_RT and NOHZ is active:
3042 * The idle task calls get_next_timer_interrupt() and holds
3043 * the timer wheel base->lock on the CPU and another CPU wants
3044 * to access the timer (probably to cancel it). We can safely
3045 * ignore the boosting request, as the idle CPU runs this code
3046 * with interrupts disabled and will complete the lock
3047 * protected section without being interrupted. So there is no
3048 * real need to boost.
3050 if (unlikely(p
== rq
->idle
)) {
3051 WARN_ON(p
!= rq
->curr
);
3052 WARN_ON(p
->pi_blocked_on
);
3056 trace_sched_pi_setprio(p
, prio
);
3058 prev_class
= p
->sched_class
;
3060 running
= task_current(rq
, p
);
3062 dequeue_task(rq
, p
, 0);
3064 p
->sched_class
->put_prev_task(rq
, p
);
3067 p
->sched_class
= &rt_sched_class
;
3069 p
->sched_class
= &fair_sched_class
;
3074 p
->sched_class
->set_curr_task(rq
);
3076 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
3078 check_class_changed(rq
, p
, prev_class
, oldprio
);
3080 __task_rq_unlock(rq
);
3083 void set_user_nice(struct task_struct
*p
, long nice
)
3085 int old_prio
, delta
, on_rq
;
3086 unsigned long flags
;
3089 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
3092 * We have to be careful, if called from sys_setpriority(),
3093 * the task might be in the middle of scheduling on another CPU.
3095 rq
= task_rq_lock(p
, &flags
);
3097 * The RT priorities are set via sched_setscheduler(), but we still
3098 * allow the 'normal' nice value to be set - but as expected
3099 * it wont have any effect on scheduling until the task is
3100 * SCHED_FIFO/SCHED_RR:
3102 if (task_has_rt_policy(p
)) {
3103 p
->static_prio
= NICE_TO_PRIO(nice
);
3108 dequeue_task(rq
, p
, 0);
3110 p
->static_prio
= NICE_TO_PRIO(nice
);
3113 p
->prio
= effective_prio(p
);
3114 delta
= p
->prio
- old_prio
;
3117 enqueue_task(rq
, p
, 0);
3119 * If the task increased its priority or is running and
3120 * lowered its priority, then reschedule its CPU:
3122 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3123 resched_task(rq
->curr
);
3126 task_rq_unlock(rq
, p
, &flags
);
3128 EXPORT_SYMBOL(set_user_nice
);
3131 * can_nice - check if a task can reduce its nice value
3135 int can_nice(const struct task_struct
*p
, const int nice
)
3137 /* convert nice value [19,-20] to rlimit style value [1,40] */
3138 int nice_rlim
= 20 - nice
;
3140 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3141 capable(CAP_SYS_NICE
));
3144 #ifdef __ARCH_WANT_SYS_NICE
3147 * sys_nice - change the priority of the current process.
3148 * @increment: priority increment
3150 * sys_setpriority is a more generic, but much slower function that
3151 * does similar things.
3153 SYSCALL_DEFINE1(nice
, int, increment
)
3158 * Setpriority might change our priority at the same moment.
3159 * We don't have to worry. Conceptually one call occurs first
3160 * and we have a single winner.
3162 if (increment
< -40)
3167 nice
= TASK_NICE(current
) + increment
;
3173 if (increment
< 0 && !can_nice(current
, nice
))
3176 retval
= security_task_setnice(current
, nice
);
3180 set_user_nice(current
, nice
);
3187 * task_prio - return the priority value of a given task.
3188 * @p: the task in question.
3190 * This is the priority value as seen by users in /proc.
3191 * RT tasks are offset by -200. Normal tasks are centered
3192 * around 0, value goes from -16 to +15.
3194 int task_prio(const struct task_struct
*p
)
3196 return p
->prio
- MAX_RT_PRIO
;
3200 * task_nice - return the nice value of a given task.
3201 * @p: the task in question.
3203 int task_nice(const struct task_struct
*p
)
3205 return TASK_NICE(p
);
3207 EXPORT_SYMBOL(task_nice
);
3210 * idle_cpu - is a given cpu idle currently?
3211 * @cpu: the processor in question.
3213 int idle_cpu(int cpu
)
3215 struct rq
*rq
= cpu_rq(cpu
);
3217 if (rq
->curr
!= rq
->idle
)
3224 if (!llist_empty(&rq
->wake_list
))
3232 * idle_task - return the idle task for a given cpu.
3233 * @cpu: the processor in question.
3235 struct task_struct
*idle_task(int cpu
)
3237 return cpu_rq(cpu
)->idle
;
3241 * find_process_by_pid - find a process with a matching PID value.
3242 * @pid: the pid in question.
3244 static struct task_struct
*find_process_by_pid(pid_t pid
)
3246 return pid
? find_task_by_vpid(pid
) : current
;
3249 /* Actually do priority change: must hold rq lock. */
3251 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
3254 p
->rt_priority
= prio
;
3255 p
->normal_prio
= normal_prio(p
);
3256 /* we are holding p->pi_lock already */
3257 p
->prio
= rt_mutex_getprio(p
);
3258 if (rt_prio(p
->prio
))
3259 p
->sched_class
= &rt_sched_class
;
3261 p
->sched_class
= &fair_sched_class
;
3266 * check the target process has a UID that matches the current process's
3268 static bool check_same_owner(struct task_struct
*p
)
3270 const struct cred
*cred
= current_cred(), *pcred
;
3274 pcred
= __task_cred(p
);
3275 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3276 uid_eq(cred
->euid
, pcred
->uid
));
3281 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
3282 const struct sched_param
*param
, bool user
)
3284 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
3285 unsigned long flags
;
3286 const struct sched_class
*prev_class
;
3290 /* may grab non-irq protected spin_locks */
3291 BUG_ON(in_interrupt());
3293 /* double check policy once rq lock held */
3295 reset_on_fork
= p
->sched_reset_on_fork
;
3296 policy
= oldpolicy
= p
->policy
;
3298 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
3299 policy
&= ~SCHED_RESET_ON_FORK
;
3301 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3302 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3303 policy
!= SCHED_IDLE
)
3308 * Valid priorities for SCHED_FIFO and SCHED_RR are
3309 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3310 * SCHED_BATCH and SCHED_IDLE is 0.
3312 if (param
->sched_priority
< 0 ||
3313 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3314 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
3316 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
3320 * Allow unprivileged RT tasks to decrease priority:
3322 if (user
&& !capable(CAP_SYS_NICE
)) {
3323 if (rt_policy(policy
)) {
3324 unsigned long rlim_rtprio
=
3325 task_rlimit(p
, RLIMIT_RTPRIO
);
3327 /* can't set/change the rt policy */
3328 if (policy
!= p
->policy
&& !rlim_rtprio
)
3331 /* can't increase priority */
3332 if (param
->sched_priority
> p
->rt_priority
&&
3333 param
->sched_priority
> rlim_rtprio
)
3338 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3339 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3341 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3342 if (!can_nice(p
, TASK_NICE(p
)))
3346 /* can't change other user's priorities */
3347 if (!check_same_owner(p
))
3350 /* Normal users shall not reset the sched_reset_on_fork flag */
3351 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3356 retval
= security_task_setscheduler(p
);
3362 * make sure no PI-waiters arrive (or leave) while we are
3363 * changing the priority of the task:
3365 * To be able to change p->policy safely, the appropriate
3366 * runqueue lock must be held.
3368 rq
= task_rq_lock(p
, &flags
);
3371 * Changing the policy of the stop threads its a very bad idea
3373 if (p
== rq
->stop
) {
3374 task_rq_unlock(rq
, p
, &flags
);
3379 * If not changing anything there's no need to proceed further:
3381 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
3382 param
->sched_priority
== p
->rt_priority
))) {
3383 task_rq_unlock(rq
, p
, &flags
);
3387 #ifdef CONFIG_RT_GROUP_SCHED
3390 * Do not allow realtime tasks into groups that have no runtime
3393 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3394 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3395 !task_group_is_autogroup(task_group(p
))) {
3396 task_rq_unlock(rq
, p
, &flags
);
3402 /* recheck policy now with rq lock held */
3403 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3404 policy
= oldpolicy
= -1;
3405 task_rq_unlock(rq
, p
, &flags
);
3409 running
= task_current(rq
, p
);
3411 dequeue_task(rq
, p
, 0);
3413 p
->sched_class
->put_prev_task(rq
, p
);
3415 p
->sched_reset_on_fork
= reset_on_fork
;
3418 prev_class
= p
->sched_class
;
3419 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
3422 p
->sched_class
->set_curr_task(rq
);
3424 enqueue_task(rq
, p
, 0);
3426 check_class_changed(rq
, p
, prev_class
, oldprio
);
3427 task_rq_unlock(rq
, p
, &flags
);
3429 rt_mutex_adjust_pi(p
);
3435 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3436 * @p: the task in question.
3437 * @policy: new policy.
3438 * @param: structure containing the new RT priority.
3440 * NOTE that the task may be already dead.
3442 int sched_setscheduler(struct task_struct
*p
, int policy
,
3443 const struct sched_param
*param
)
3445 return __sched_setscheduler(p
, policy
, param
, true);
3447 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3450 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3451 * @p: the task in question.
3452 * @policy: new policy.
3453 * @param: structure containing the new RT priority.
3455 * Just like sched_setscheduler, only don't bother checking if the
3456 * current context has permission. For example, this is needed in
3457 * stop_machine(): we create temporary high priority worker threads,
3458 * but our caller might not have that capability.
3460 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3461 const struct sched_param
*param
)
3463 return __sched_setscheduler(p
, policy
, param
, false);
3467 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3469 struct sched_param lparam
;
3470 struct task_struct
*p
;
3473 if (!param
|| pid
< 0)
3475 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3480 p
= find_process_by_pid(pid
);
3482 retval
= sched_setscheduler(p
, policy
, &lparam
);
3489 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3490 * @pid: the pid in question.
3491 * @policy: new policy.
3492 * @param: structure containing the new RT priority.
3494 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3495 struct sched_param __user
*, param
)
3497 /* negative values for policy are not valid */
3501 return do_sched_setscheduler(pid
, policy
, param
);
3505 * sys_sched_setparam - set/change the RT priority of a thread
3506 * @pid: the pid in question.
3507 * @param: structure containing the new RT priority.
3509 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3511 return do_sched_setscheduler(pid
, -1, param
);
3515 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3516 * @pid: the pid in question.
3518 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3520 struct task_struct
*p
;
3528 p
= find_process_by_pid(pid
);
3530 retval
= security_task_getscheduler(p
);
3533 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3540 * sys_sched_getparam - get the RT priority of a thread
3541 * @pid: the pid in question.
3542 * @param: structure containing the RT priority.
3544 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3546 struct sched_param lp
;
3547 struct task_struct
*p
;
3550 if (!param
|| pid
< 0)
3554 p
= find_process_by_pid(pid
);
3559 retval
= security_task_getscheduler(p
);
3563 lp
.sched_priority
= p
->rt_priority
;
3567 * This one might sleep, we cannot do it with a spinlock held ...
3569 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3578 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
3580 cpumask_var_t cpus_allowed
, new_mask
;
3581 struct task_struct
*p
;
3587 p
= find_process_by_pid(pid
);
3594 /* Prevent p going away */
3598 if (p
->flags
& PF_NO_SETAFFINITY
) {
3602 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
3606 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
3608 goto out_free_cpus_allowed
;
3611 if (!check_same_owner(p
)) {
3613 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
3620 retval
= security_task_setscheduler(p
);
3624 cpuset_cpus_allowed(p
, cpus_allowed
);
3625 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
3627 retval
= set_cpus_allowed_ptr(p
, new_mask
);
3630 cpuset_cpus_allowed(p
, cpus_allowed
);
3631 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
3633 * We must have raced with a concurrent cpuset
3634 * update. Just reset the cpus_allowed to the
3635 * cpuset's cpus_allowed
3637 cpumask_copy(new_mask
, cpus_allowed
);
3642 free_cpumask_var(new_mask
);
3643 out_free_cpus_allowed
:
3644 free_cpumask_var(cpus_allowed
);
3651 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
3652 struct cpumask
*new_mask
)
3654 if (len
< cpumask_size())
3655 cpumask_clear(new_mask
);
3656 else if (len
> cpumask_size())
3657 len
= cpumask_size();
3659 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
3663 * sys_sched_setaffinity - set the cpu affinity of a process
3664 * @pid: pid of the process
3665 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3666 * @user_mask_ptr: user-space pointer to the new cpu mask
3668 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
3669 unsigned long __user
*, user_mask_ptr
)
3671 cpumask_var_t new_mask
;
3674 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
3677 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
3679 retval
= sched_setaffinity(pid
, new_mask
);
3680 free_cpumask_var(new_mask
);
3684 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
3686 struct task_struct
*p
;
3687 unsigned long flags
;
3694 p
= find_process_by_pid(pid
);
3698 retval
= security_task_getscheduler(p
);
3702 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
3703 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
3704 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
3714 * sys_sched_getaffinity - get the cpu affinity of a process
3715 * @pid: pid of the process
3716 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3717 * @user_mask_ptr: user-space pointer to hold the current cpu mask
3719 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
3720 unsigned long __user
*, user_mask_ptr
)
3725 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
3727 if (len
& (sizeof(unsigned long)-1))
3730 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
3733 ret
= sched_getaffinity(pid
, mask
);
3735 size_t retlen
= min_t(size_t, len
, cpumask_size());
3737 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
3742 free_cpumask_var(mask
);
3748 * sys_sched_yield - yield the current processor to other threads.
3750 * This function yields the current CPU to other tasks. If there are no
3751 * other threads running on this CPU then this function will return.
3753 SYSCALL_DEFINE0(sched_yield
)
3755 struct rq
*rq
= this_rq_lock();
3757 schedstat_inc(rq
, yld_count
);
3758 current
->sched_class
->yield_task(rq
);
3761 * Since we are going to call schedule() anyway, there's
3762 * no need to preempt or enable interrupts:
3764 __release(rq
->lock
);
3765 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
3766 do_raw_spin_unlock(&rq
->lock
);
3767 sched_preempt_enable_no_resched();
3774 static inline int should_resched(void)
3776 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
3779 static void __cond_resched(void)
3781 add_preempt_count(PREEMPT_ACTIVE
);
3783 sub_preempt_count(PREEMPT_ACTIVE
);
3786 int __sched
_cond_resched(void)
3788 if (should_resched()) {
3794 EXPORT_SYMBOL(_cond_resched
);
3797 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
3798 * call schedule, and on return reacquire the lock.
3800 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
3801 * operations here to prevent schedule() from being called twice (once via
3802 * spin_unlock(), once by hand).
3804 int __cond_resched_lock(spinlock_t
*lock
)
3806 int resched
= should_resched();
3809 lockdep_assert_held(lock
);
3811 if (spin_needbreak(lock
) || resched
) {
3822 EXPORT_SYMBOL(__cond_resched_lock
);
3824 int __sched
__cond_resched_softirq(void)
3826 BUG_ON(!in_softirq());
3828 if (should_resched()) {
3836 EXPORT_SYMBOL(__cond_resched_softirq
);
3839 * yield - yield the current processor to other threads.
3841 * Do not ever use this function, there's a 99% chance you're doing it wrong.
3843 * The scheduler is at all times free to pick the calling task as the most
3844 * eligible task to run, if removing the yield() call from your code breaks
3845 * it, its already broken.
3847 * Typical broken usage is:
3852 * where one assumes that yield() will let 'the other' process run that will
3853 * make event true. If the current task is a SCHED_FIFO task that will never
3854 * happen. Never use yield() as a progress guarantee!!
3856 * If you want to use yield() to wait for something, use wait_event().
3857 * If you want to use yield() to be 'nice' for others, use cond_resched().
3858 * If you still want to use yield(), do not!
3860 void __sched
yield(void)
3862 set_current_state(TASK_RUNNING
);
3865 EXPORT_SYMBOL(yield
);
3868 * yield_to - yield the current processor to another thread in
3869 * your thread group, or accelerate that thread toward the
3870 * processor it's on.
3872 * @preempt: whether task preemption is allowed or not
3874 * It's the caller's job to ensure that the target task struct
3875 * can't go away on us before we can do any checks.
3878 * true (>0) if we indeed boosted the target task.
3879 * false (0) if we failed to boost the target.
3880 * -ESRCH if there's no task to yield to.
3882 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
3884 struct task_struct
*curr
= current
;
3885 struct rq
*rq
, *p_rq
;
3886 unsigned long flags
;
3889 local_irq_save(flags
);
3895 * If we're the only runnable task on the rq and target rq also
3896 * has only one task, there's absolutely no point in yielding.
3898 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
3903 double_rq_lock(rq
, p_rq
);
3904 while (task_rq(p
) != p_rq
) {
3905 double_rq_unlock(rq
, p_rq
);
3909 if (!curr
->sched_class
->yield_to_task
)
3912 if (curr
->sched_class
!= p
->sched_class
)
3915 if (task_running(p_rq
, p
) || p
->state
)
3918 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
3920 schedstat_inc(rq
, yld_count
);
3922 * Make p's CPU reschedule; pick_next_entity takes care of
3925 if (preempt
&& rq
!= p_rq
)
3926 resched_task(p_rq
->curr
);
3930 double_rq_unlock(rq
, p_rq
);
3932 local_irq_restore(flags
);
3939 EXPORT_SYMBOL_GPL(yield_to
);
3942 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
3943 * that process accounting knows that this is a task in IO wait state.
3945 void __sched
io_schedule(void)
3947 struct rq
*rq
= raw_rq();
3949 delayacct_blkio_start();
3950 atomic_inc(&rq
->nr_iowait
);
3951 blk_flush_plug(current
);
3952 current
->in_iowait
= 1;
3954 current
->in_iowait
= 0;
3955 atomic_dec(&rq
->nr_iowait
);
3956 delayacct_blkio_end();
3958 EXPORT_SYMBOL(io_schedule
);
3960 long __sched
io_schedule_timeout(long timeout
)
3962 struct rq
*rq
= raw_rq();
3965 delayacct_blkio_start();
3966 atomic_inc(&rq
->nr_iowait
);
3967 blk_flush_plug(current
);
3968 current
->in_iowait
= 1;
3969 ret
= schedule_timeout(timeout
);
3970 current
->in_iowait
= 0;
3971 atomic_dec(&rq
->nr_iowait
);
3972 delayacct_blkio_end();
3977 * sys_sched_get_priority_max - return maximum RT priority.
3978 * @policy: scheduling class.
3980 * this syscall returns the maximum rt_priority that can be used
3981 * by a given scheduling class.
3983 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
3990 ret
= MAX_USER_RT_PRIO
-1;
4002 * sys_sched_get_priority_min - return minimum RT priority.
4003 * @policy: scheduling class.
4005 * this syscall returns the minimum rt_priority that can be used
4006 * by a given scheduling class.
4008 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4026 * sys_sched_rr_get_interval - return the default timeslice of a process.
4027 * @pid: pid of the process.
4028 * @interval: userspace pointer to the timeslice value.
4030 * this syscall writes the default timeslice value of a given process
4031 * into the user-space timespec buffer. A value of '0' means infinity.
4033 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4034 struct timespec __user
*, interval
)
4036 struct task_struct
*p
;
4037 unsigned int time_slice
;
4038 unsigned long flags
;
4048 p
= find_process_by_pid(pid
);
4052 retval
= security_task_getscheduler(p
);
4056 rq
= task_rq_lock(p
, &flags
);
4057 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4058 task_rq_unlock(rq
, p
, &flags
);
4061 jiffies_to_timespec(time_slice
, &t
);
4062 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4070 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4072 void sched_show_task(struct task_struct
*p
)
4074 unsigned long free
= 0;
4078 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4079 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4080 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4081 #if BITS_PER_LONG == 32
4082 if (state
== TASK_RUNNING
)
4083 printk(KERN_CONT
" running ");
4085 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4087 if (state
== TASK_RUNNING
)
4088 printk(KERN_CONT
" running task ");
4090 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4092 #ifdef CONFIG_DEBUG_STACK_USAGE
4093 free
= stack_not_used(p
);
4096 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4098 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4099 task_pid_nr(p
), ppid
,
4100 (unsigned long)task_thread_info(p
)->flags
);
4102 print_worker_info(KERN_INFO
, p
);
4103 show_stack(p
, NULL
);
4106 void show_state_filter(unsigned long state_filter
)
4108 struct task_struct
*g
, *p
;
4110 #if BITS_PER_LONG == 32
4112 " task PC stack pid father\n");
4115 " task PC stack pid father\n");
4118 do_each_thread(g
, p
) {
4120 * reset the NMI-timeout, listing all files on a slow
4121 * console might take a lot of time:
4123 touch_nmi_watchdog();
4124 if (!state_filter
|| (p
->state
& state_filter
))
4126 } while_each_thread(g
, p
);
4128 touch_all_softlockup_watchdogs();
4130 #ifdef CONFIG_SCHED_DEBUG
4131 sysrq_sched_debug_show();
4135 * Only show locks if all tasks are dumped:
4138 debug_show_all_locks();
4141 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
4143 idle
->sched_class
= &idle_sched_class
;
4147 * init_idle - set up an idle thread for a given CPU
4148 * @idle: task in question
4149 * @cpu: cpu the idle task belongs to
4151 * NOTE: this function does not set the idle thread's NEED_RESCHED
4152 * flag, to make booting more robust.
4154 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
4156 struct rq
*rq
= cpu_rq(cpu
);
4157 unsigned long flags
;
4159 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4162 idle
->state
= TASK_RUNNING
;
4163 idle
->se
.exec_start
= sched_clock();
4165 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4167 * We're having a chicken and egg problem, even though we are
4168 * holding rq->lock, the cpu isn't yet set to this cpu so the
4169 * lockdep check in task_group() will fail.
4171 * Similar case to sched_fork(). / Alternatively we could
4172 * use task_rq_lock() here and obtain the other rq->lock.
4177 __set_task_cpu(idle
, cpu
);
4180 rq
->curr
= rq
->idle
= idle
;
4181 #if defined(CONFIG_SMP)
4184 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4186 /* Set the preempt count _outside_ the spinlocks! */
4187 task_thread_info(idle
)->preempt_count
= 0;
4190 * The idle tasks have their own, simple scheduling class:
4192 idle
->sched_class
= &idle_sched_class
;
4193 ftrace_graph_init_idle_task(idle
, cpu
);
4194 vtime_init_idle(idle
);
4195 #if defined(CONFIG_SMP)
4196 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4201 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4203 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4204 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4206 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4207 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4211 * This is how migration works:
4213 * 1) we invoke migration_cpu_stop() on the target CPU using
4215 * 2) stopper starts to run (implicitly forcing the migrated thread
4217 * 3) it checks whether the migrated task is still in the wrong runqueue.
4218 * 4) if it's in the wrong runqueue then the migration thread removes
4219 * it and puts it into the right queue.
4220 * 5) stopper completes and stop_one_cpu() returns and the migration
4225 * Change a given task's CPU affinity. Migrate the thread to a
4226 * proper CPU and schedule it away if the CPU it's executing on
4227 * is removed from the allowed bitmask.
4229 * NOTE: the caller must have a valid reference to the task, the
4230 * task must not exit() & deallocate itself prematurely. The
4231 * call is not atomic; no spinlocks may be held.
4233 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4235 unsigned long flags
;
4237 unsigned int dest_cpu
;
4240 rq
= task_rq_lock(p
, &flags
);
4242 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4245 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4250 do_set_cpus_allowed(p
, new_mask
);
4252 /* Can the task run on the task's current CPU? If so, we're done */
4253 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4256 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4258 struct migration_arg arg
= { p
, dest_cpu
};
4259 /* Need help from migration thread: drop lock and wait. */
4260 task_rq_unlock(rq
, p
, &flags
);
4261 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4262 tlb_migrate_finish(p
->mm
);
4266 task_rq_unlock(rq
, p
, &flags
);
4270 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4273 * Move (not current) task off this cpu, onto dest cpu. We're doing
4274 * this because either it can't run here any more (set_cpus_allowed()
4275 * away from this CPU, or CPU going down), or because we're
4276 * attempting to rebalance this task on exec (sched_exec).
4278 * So we race with normal scheduler movements, but that's OK, as long
4279 * as the task is no longer on this CPU.
4281 * Returns non-zero if task was successfully migrated.
4283 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4285 struct rq
*rq_dest
, *rq_src
;
4288 if (unlikely(!cpu_active(dest_cpu
)))
4291 rq_src
= cpu_rq(src_cpu
);
4292 rq_dest
= cpu_rq(dest_cpu
);
4294 raw_spin_lock(&p
->pi_lock
);
4295 double_rq_lock(rq_src
, rq_dest
);
4296 /* Already moved. */
4297 if (task_cpu(p
) != src_cpu
)
4299 /* Affinity changed (again). */
4300 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4304 * If we're not on a rq, the next wake-up will ensure we're
4308 dequeue_task(rq_src
, p
, 0);
4309 set_task_cpu(p
, dest_cpu
);
4310 enqueue_task(rq_dest
, p
, 0);
4311 check_preempt_curr(rq_dest
, p
, 0);
4316 double_rq_unlock(rq_src
, rq_dest
);
4317 raw_spin_unlock(&p
->pi_lock
);
4322 * migration_cpu_stop - this will be executed by a highprio stopper thread
4323 * and performs thread migration by bumping thread off CPU then
4324 * 'pushing' onto another runqueue.
4326 static int migration_cpu_stop(void *data
)
4328 struct migration_arg
*arg
= data
;
4331 * The original target cpu might have gone down and we might
4332 * be on another cpu but it doesn't matter.
4334 local_irq_disable();
4335 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4340 #ifdef CONFIG_HOTPLUG_CPU
4343 * Ensures that the idle task is using init_mm right before its cpu goes
4346 void idle_task_exit(void)
4348 struct mm_struct
*mm
= current
->active_mm
;
4350 BUG_ON(cpu_online(smp_processor_id()));
4353 switch_mm(mm
, &init_mm
, current
);
4358 * Since this CPU is going 'away' for a while, fold any nr_active delta
4359 * we might have. Assumes we're called after migrate_tasks() so that the
4360 * nr_active count is stable.
4362 * Also see the comment "Global load-average calculations".
4364 static void calc_load_migrate(struct rq
*rq
)
4366 long delta
= calc_load_fold_active(rq
);
4368 atomic_long_add(delta
, &calc_load_tasks
);
4372 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4373 * try_to_wake_up()->select_task_rq().
4375 * Called with rq->lock held even though we'er in stop_machine() and
4376 * there's no concurrency possible, we hold the required locks anyway
4377 * because of lock validation efforts.
4379 static void migrate_tasks(unsigned int dead_cpu
)
4381 struct rq
*rq
= cpu_rq(dead_cpu
);
4382 struct task_struct
*next
, *stop
= rq
->stop
;
4386 * Fudge the rq selection such that the below task selection loop
4387 * doesn't get stuck on the currently eligible stop task.
4389 * We're currently inside stop_machine() and the rq is either stuck
4390 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4391 * either way we should never end up calling schedule() until we're
4397 * put_prev_task() and pick_next_task() sched
4398 * class method both need to have an up-to-date
4399 * value of rq->clock[_task]
4401 update_rq_clock(rq
);
4405 * There's this thread running, bail when that's the only
4408 if (rq
->nr_running
== 1)
4411 next
= pick_next_task(rq
);
4413 next
->sched_class
->put_prev_task(rq
, next
);
4415 /* Find suitable destination for @next, with force if needed. */
4416 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
4417 raw_spin_unlock(&rq
->lock
);
4419 __migrate_task(next
, dead_cpu
, dest_cpu
);
4421 raw_spin_lock(&rq
->lock
);
4427 #endif /* CONFIG_HOTPLUG_CPU */
4429 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4431 static struct ctl_table sd_ctl_dir
[] = {
4433 .procname
= "sched_domain",
4439 static struct ctl_table sd_ctl_root
[] = {
4441 .procname
= "kernel",
4443 .child
= sd_ctl_dir
,
4448 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
4450 struct ctl_table
*entry
=
4451 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
4456 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
4458 struct ctl_table
*entry
;
4461 * In the intermediate directories, both the child directory and
4462 * procname are dynamically allocated and could fail but the mode
4463 * will always be set. In the lowest directory the names are
4464 * static strings and all have proc handlers.
4466 for (entry
= *tablep
; entry
->mode
; entry
++) {
4468 sd_free_ctl_entry(&entry
->child
);
4469 if (entry
->proc_handler
== NULL
)
4470 kfree(entry
->procname
);
4477 static int min_load_idx
= 0;
4478 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
4481 set_table_entry(struct ctl_table
*entry
,
4482 const char *procname
, void *data
, int maxlen
,
4483 umode_t mode
, proc_handler
*proc_handler
,
4486 entry
->procname
= procname
;
4488 entry
->maxlen
= maxlen
;
4490 entry
->proc_handler
= proc_handler
;
4493 entry
->extra1
= &min_load_idx
;
4494 entry
->extra2
= &max_load_idx
;
4498 static struct ctl_table
*
4499 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
4501 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
4506 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
4507 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4508 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
4509 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4510 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
4511 sizeof(int), 0644, proc_dointvec_minmax
, true);
4512 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
4513 sizeof(int), 0644, proc_dointvec_minmax
, true);
4514 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
4515 sizeof(int), 0644, proc_dointvec_minmax
, true);
4516 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
4517 sizeof(int), 0644, proc_dointvec_minmax
, true);
4518 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
4519 sizeof(int), 0644, proc_dointvec_minmax
, true);
4520 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
4521 sizeof(int), 0644, proc_dointvec_minmax
, false);
4522 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
4523 sizeof(int), 0644, proc_dointvec_minmax
, false);
4524 set_table_entry(&table
[9], "cache_nice_tries",
4525 &sd
->cache_nice_tries
,
4526 sizeof(int), 0644, proc_dointvec_minmax
, false);
4527 set_table_entry(&table
[10], "flags", &sd
->flags
,
4528 sizeof(int), 0644, proc_dointvec_minmax
, false);
4529 set_table_entry(&table
[11], "name", sd
->name
,
4530 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
4531 /* &table[12] is terminator */
4536 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
4538 struct ctl_table
*entry
, *table
;
4539 struct sched_domain
*sd
;
4540 int domain_num
= 0, i
;
4543 for_each_domain(cpu
, sd
)
4545 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
4550 for_each_domain(cpu
, sd
) {
4551 snprintf(buf
, 32, "domain%d", i
);
4552 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4554 entry
->child
= sd_alloc_ctl_domain_table(sd
);
4561 static struct ctl_table_header
*sd_sysctl_header
;
4562 static void register_sched_domain_sysctl(void)
4564 int i
, cpu_num
= num_possible_cpus();
4565 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
4568 WARN_ON(sd_ctl_dir
[0].child
);
4569 sd_ctl_dir
[0].child
= entry
;
4574 for_each_possible_cpu(i
) {
4575 snprintf(buf
, 32, "cpu%d", i
);
4576 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4578 entry
->child
= sd_alloc_ctl_cpu_table(i
);
4582 WARN_ON(sd_sysctl_header
);
4583 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
4586 /* may be called multiple times per register */
4587 static void unregister_sched_domain_sysctl(void)
4589 if (sd_sysctl_header
)
4590 unregister_sysctl_table(sd_sysctl_header
);
4591 sd_sysctl_header
= NULL
;
4592 if (sd_ctl_dir
[0].child
)
4593 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
4596 static void register_sched_domain_sysctl(void)
4599 static void unregister_sched_domain_sysctl(void)
4604 static void set_rq_online(struct rq
*rq
)
4607 const struct sched_class
*class;
4609 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
4612 for_each_class(class) {
4613 if (class->rq_online
)
4614 class->rq_online(rq
);
4619 static void set_rq_offline(struct rq
*rq
)
4622 const struct sched_class
*class;
4624 for_each_class(class) {
4625 if (class->rq_offline
)
4626 class->rq_offline(rq
);
4629 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
4635 * migration_call - callback that gets triggered when a CPU is added.
4636 * Here we can start up the necessary migration thread for the new CPU.
4638 static int __cpuinit
4639 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
4641 int cpu
= (long)hcpu
;
4642 unsigned long flags
;
4643 struct rq
*rq
= cpu_rq(cpu
);
4645 switch (action
& ~CPU_TASKS_FROZEN
) {
4647 case CPU_UP_PREPARE
:
4648 rq
->calc_load_update
= calc_load_update
;
4652 /* Update our root-domain */
4653 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4655 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
4659 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4662 #ifdef CONFIG_HOTPLUG_CPU
4664 sched_ttwu_pending();
4665 /* Update our root-domain */
4666 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4668 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
4672 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
4673 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4677 calc_load_migrate(rq
);
4682 update_max_interval();
4688 * Register at high priority so that task migration (migrate_all_tasks)
4689 * happens before everything else. This has to be lower priority than
4690 * the notifier in the perf_event subsystem, though.
4692 static struct notifier_block __cpuinitdata migration_notifier
= {
4693 .notifier_call
= migration_call
,
4694 .priority
= CPU_PRI_MIGRATION
,
4697 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
4698 unsigned long action
, void *hcpu
)
4700 switch (action
& ~CPU_TASKS_FROZEN
) {
4702 case CPU_DOWN_FAILED
:
4703 set_cpu_active((long)hcpu
, true);
4710 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
4711 unsigned long action
, void *hcpu
)
4713 switch (action
& ~CPU_TASKS_FROZEN
) {
4714 case CPU_DOWN_PREPARE
:
4715 set_cpu_active((long)hcpu
, false);
4722 static int __init
migration_init(void)
4724 void *cpu
= (void *)(long)smp_processor_id();
4727 /* Initialize migration for the boot CPU */
4728 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
4729 BUG_ON(err
== NOTIFY_BAD
);
4730 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
4731 register_cpu_notifier(&migration_notifier
);
4733 /* Register cpu active notifiers */
4734 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
4735 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
4739 early_initcall(migration_init
);
4744 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
4746 #ifdef CONFIG_SCHED_DEBUG
4748 static __read_mostly
int sched_debug_enabled
;
4750 static int __init
sched_debug_setup(char *str
)
4752 sched_debug_enabled
= 1;
4756 early_param("sched_debug", sched_debug_setup
);
4758 static inline bool sched_debug(void)
4760 return sched_debug_enabled
;
4763 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
4764 struct cpumask
*groupmask
)
4766 struct sched_group
*group
= sd
->groups
;
4769 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
4770 cpumask_clear(groupmask
);
4772 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
4774 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
4775 printk("does not load-balance\n");
4777 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
4782 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
4784 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
4785 printk(KERN_ERR
"ERROR: domain->span does not contain "
4788 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
4789 printk(KERN_ERR
"ERROR: domain->groups does not contain"
4793 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
4797 printk(KERN_ERR
"ERROR: group is NULL\n");
4802 * Even though we initialize ->power to something semi-sane,
4803 * we leave power_orig unset. This allows us to detect if
4804 * domain iteration is still funny without causing /0 traps.
4806 if (!group
->sgp
->power_orig
) {
4807 printk(KERN_CONT
"\n");
4808 printk(KERN_ERR
"ERROR: domain->cpu_power not "
4813 if (!cpumask_weight(sched_group_cpus(group
))) {
4814 printk(KERN_CONT
"\n");
4815 printk(KERN_ERR
"ERROR: empty group\n");
4819 if (!(sd
->flags
& SD_OVERLAP
) &&
4820 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
4821 printk(KERN_CONT
"\n");
4822 printk(KERN_ERR
"ERROR: repeated CPUs\n");
4826 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
4828 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
4830 printk(KERN_CONT
" %s", str
);
4831 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
4832 printk(KERN_CONT
" (cpu_power = %d)",
4836 group
= group
->next
;
4837 } while (group
!= sd
->groups
);
4838 printk(KERN_CONT
"\n");
4840 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
4841 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
4844 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
4845 printk(KERN_ERR
"ERROR: parent span is not a superset "
4846 "of domain->span\n");
4850 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
4854 if (!sched_debug_enabled
)
4858 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
4862 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
4865 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
4873 #else /* !CONFIG_SCHED_DEBUG */
4874 # define sched_domain_debug(sd, cpu) do { } while (0)
4875 static inline bool sched_debug(void)
4879 #endif /* CONFIG_SCHED_DEBUG */
4881 static int sd_degenerate(struct sched_domain
*sd
)
4883 if (cpumask_weight(sched_domain_span(sd
)) == 1)
4886 /* Following flags need at least 2 groups */
4887 if (sd
->flags
& (SD_LOAD_BALANCE
|
4888 SD_BALANCE_NEWIDLE
|
4892 SD_SHARE_PKG_RESOURCES
)) {
4893 if (sd
->groups
!= sd
->groups
->next
)
4897 /* Following flags don't use groups */
4898 if (sd
->flags
& (SD_WAKE_AFFINE
))
4905 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
4907 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
4909 if (sd_degenerate(parent
))
4912 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
4915 /* Flags needing groups don't count if only 1 group in parent */
4916 if (parent
->groups
== parent
->groups
->next
) {
4917 pflags
&= ~(SD_LOAD_BALANCE
|
4918 SD_BALANCE_NEWIDLE
|
4922 SD_SHARE_PKG_RESOURCES
);
4923 if (nr_node_ids
== 1)
4924 pflags
&= ~SD_SERIALIZE
;
4926 if (~cflags
& pflags
)
4932 static void free_rootdomain(struct rcu_head
*rcu
)
4934 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
4936 cpupri_cleanup(&rd
->cpupri
);
4937 free_cpumask_var(rd
->rto_mask
);
4938 free_cpumask_var(rd
->online
);
4939 free_cpumask_var(rd
->span
);
4943 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
4945 struct root_domain
*old_rd
= NULL
;
4946 unsigned long flags
;
4948 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4953 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
4956 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
4959 * If we dont want to free the old_rt yet then
4960 * set old_rd to NULL to skip the freeing later
4963 if (!atomic_dec_and_test(&old_rd
->refcount
))
4967 atomic_inc(&rd
->refcount
);
4970 cpumask_set_cpu(rq
->cpu
, rd
->span
);
4971 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
4974 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4977 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
4980 static int init_rootdomain(struct root_domain
*rd
)
4982 memset(rd
, 0, sizeof(*rd
));
4984 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
4986 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
4988 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
4991 if (cpupri_init(&rd
->cpupri
) != 0)
4996 free_cpumask_var(rd
->rto_mask
);
4998 free_cpumask_var(rd
->online
);
5000 free_cpumask_var(rd
->span
);
5006 * By default the system creates a single root-domain with all cpus as
5007 * members (mimicking the global state we have today).
5009 struct root_domain def_root_domain
;
5011 static void init_defrootdomain(void)
5013 init_rootdomain(&def_root_domain
);
5015 atomic_set(&def_root_domain
.refcount
, 1);
5018 static struct root_domain
*alloc_rootdomain(void)
5020 struct root_domain
*rd
;
5022 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5026 if (init_rootdomain(rd
) != 0) {
5034 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
5036 struct sched_group
*tmp
, *first
;
5045 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
5050 } while (sg
!= first
);
5053 static void free_sched_domain(struct rcu_head
*rcu
)
5055 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5058 * If its an overlapping domain it has private groups, iterate and
5061 if (sd
->flags
& SD_OVERLAP
) {
5062 free_sched_groups(sd
->groups
, 1);
5063 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5064 kfree(sd
->groups
->sgp
);
5070 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5072 call_rcu(&sd
->rcu
, free_sched_domain
);
5075 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5077 for (; sd
; sd
= sd
->parent
)
5078 destroy_sched_domain(sd
, cpu
);
5082 * Keep a special pointer to the highest sched_domain that has
5083 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5084 * allows us to avoid some pointer chasing select_idle_sibling().
5086 * Also keep a unique ID per domain (we use the first cpu number in
5087 * the cpumask of the domain), this allows us to quickly tell if
5088 * two cpus are in the same cache domain, see cpus_share_cache().
5090 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5091 DEFINE_PER_CPU(int, sd_llc_id
);
5093 static void update_top_cache_domain(int cpu
)
5095 struct sched_domain
*sd
;
5098 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5100 id
= cpumask_first(sched_domain_span(sd
));
5102 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5103 per_cpu(sd_llc_id
, cpu
) = id
;
5107 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5108 * hold the hotplug lock.
5111 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5113 struct rq
*rq
= cpu_rq(cpu
);
5114 struct sched_domain
*tmp
;
5116 /* Remove the sched domains which do not contribute to scheduling. */
5117 for (tmp
= sd
; tmp
; ) {
5118 struct sched_domain
*parent
= tmp
->parent
;
5122 if (sd_parent_degenerate(tmp
, parent
)) {
5123 tmp
->parent
= parent
->parent
;
5125 parent
->parent
->child
= tmp
;
5126 destroy_sched_domain(parent
, cpu
);
5131 if (sd
&& sd_degenerate(sd
)) {
5134 destroy_sched_domain(tmp
, cpu
);
5139 sched_domain_debug(sd
, cpu
);
5141 rq_attach_root(rq
, rd
);
5143 rcu_assign_pointer(rq
->sd
, sd
);
5144 destroy_sched_domains(tmp
, cpu
);
5146 update_top_cache_domain(cpu
);
5149 /* cpus with isolated domains */
5150 static cpumask_var_t cpu_isolated_map
;
5152 /* Setup the mask of cpus configured for isolated domains */
5153 static int __init
isolated_cpu_setup(char *str
)
5155 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5156 cpulist_parse(str
, cpu_isolated_map
);
5160 __setup("isolcpus=", isolated_cpu_setup
);
5162 static const struct cpumask
*cpu_cpu_mask(int cpu
)
5164 return cpumask_of_node(cpu_to_node(cpu
));
5168 struct sched_domain
**__percpu sd
;
5169 struct sched_group
**__percpu sg
;
5170 struct sched_group_power
**__percpu sgp
;
5174 struct sched_domain
** __percpu sd
;
5175 struct root_domain
*rd
;
5185 struct sched_domain_topology_level
;
5187 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
5188 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
5190 #define SDTL_OVERLAP 0x01
5192 struct sched_domain_topology_level
{
5193 sched_domain_init_f init
;
5194 sched_domain_mask_f mask
;
5197 struct sd_data data
;
5201 * Build an iteration mask that can exclude certain CPUs from the upwards
5204 * Asymmetric node setups can result in situations where the domain tree is of
5205 * unequal depth, make sure to skip domains that already cover the entire
5208 * In that case build_sched_domains() will have terminated the iteration early
5209 * and our sibling sd spans will be empty. Domains should always include the
5210 * cpu they're built on, so check that.
5213 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5215 const struct cpumask
*span
= sched_domain_span(sd
);
5216 struct sd_data
*sdd
= sd
->private;
5217 struct sched_domain
*sibling
;
5220 for_each_cpu(i
, span
) {
5221 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5222 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5225 cpumask_set_cpu(i
, sched_group_mask(sg
));
5230 * Return the canonical balance cpu for this group, this is the first cpu
5231 * of this group that's also in the iteration mask.
5233 int group_balance_cpu(struct sched_group
*sg
)
5235 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5239 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5241 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5242 const struct cpumask
*span
= sched_domain_span(sd
);
5243 struct cpumask
*covered
= sched_domains_tmpmask
;
5244 struct sd_data
*sdd
= sd
->private;
5245 struct sched_domain
*child
;
5248 cpumask_clear(covered
);
5250 for_each_cpu(i
, span
) {
5251 struct cpumask
*sg_span
;
5253 if (cpumask_test_cpu(i
, covered
))
5256 child
= *per_cpu_ptr(sdd
->sd
, i
);
5258 /* See the comment near build_group_mask(). */
5259 if (!cpumask_test_cpu(i
, sched_domain_span(child
)))
5262 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5263 GFP_KERNEL
, cpu_to_node(cpu
));
5268 sg_span
= sched_group_cpus(sg
);
5270 child
= child
->child
;
5271 cpumask_copy(sg_span
, sched_domain_span(child
));
5273 cpumask_set_cpu(i
, sg_span
);
5275 cpumask_or(covered
, covered
, sg_span
);
5277 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, i
);
5278 if (atomic_inc_return(&sg
->sgp
->ref
) == 1)
5279 build_group_mask(sd
, sg
);
5282 * Initialize sgp->power such that even if we mess up the
5283 * domains and no possible iteration will get us here, we won't
5286 sg
->sgp
->power
= SCHED_POWER_SCALE
* cpumask_weight(sg_span
);
5289 * Make sure the first group of this domain contains the
5290 * canonical balance cpu. Otherwise the sched_domain iteration
5291 * breaks. See update_sg_lb_stats().
5293 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5294 group_balance_cpu(sg
) == cpu
)
5304 sd
->groups
= groups
;
5309 free_sched_groups(first
, 0);
5314 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5316 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5317 struct sched_domain
*child
= sd
->child
;
5320 cpu
= cpumask_first(sched_domain_span(child
));
5323 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5324 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
5325 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
5332 * build_sched_groups will build a circular linked list of the groups
5333 * covered by the given span, and will set each group's ->cpumask correctly,
5334 * and ->cpu_power to 0.
5336 * Assumes the sched_domain tree is fully constructed
5339 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5341 struct sched_group
*first
= NULL
, *last
= NULL
;
5342 struct sd_data
*sdd
= sd
->private;
5343 const struct cpumask
*span
= sched_domain_span(sd
);
5344 struct cpumask
*covered
;
5347 get_group(cpu
, sdd
, &sd
->groups
);
5348 atomic_inc(&sd
->groups
->ref
);
5350 if (cpu
!= cpumask_first(span
))
5353 lockdep_assert_held(&sched_domains_mutex
);
5354 covered
= sched_domains_tmpmask
;
5356 cpumask_clear(covered
);
5358 for_each_cpu(i
, span
) {
5359 struct sched_group
*sg
;
5360 int group
= get_group(i
, sdd
, &sg
);
5363 if (cpumask_test_cpu(i
, covered
))
5366 cpumask_clear(sched_group_cpus(sg
));
5368 cpumask_setall(sched_group_mask(sg
));
5370 for_each_cpu(j
, span
) {
5371 if (get_group(j
, sdd
, NULL
) != group
)
5374 cpumask_set_cpu(j
, covered
);
5375 cpumask_set_cpu(j
, sched_group_cpus(sg
));
5390 * Initialize sched groups cpu_power.
5392 * cpu_power indicates the capacity of sched group, which is used while
5393 * distributing the load between different sched groups in a sched domain.
5394 * Typically cpu_power for all the groups in a sched domain will be same unless
5395 * there are asymmetries in the topology. If there are asymmetries, group
5396 * having more cpu_power will pickup more load compared to the group having
5399 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
5401 struct sched_group
*sg
= sd
->groups
;
5403 WARN_ON(!sd
|| !sg
);
5406 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
5408 } while (sg
!= sd
->groups
);
5410 if (cpu
!= group_balance_cpu(sg
))
5413 update_group_power(sd
, cpu
);
5414 atomic_set(&sg
->sgp
->nr_busy_cpus
, sg
->group_weight
);
5417 int __weak
arch_sd_sibling_asym_packing(void)
5419 return 0*SD_ASYM_PACKING
;
5423 * Initializers for schedule domains
5424 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5427 #ifdef CONFIG_SCHED_DEBUG
5428 # define SD_INIT_NAME(sd, type) sd->name = #type
5430 # define SD_INIT_NAME(sd, type) do { } while (0)
5433 #define SD_INIT_FUNC(type) \
5434 static noinline struct sched_domain * \
5435 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
5437 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
5438 *sd = SD_##type##_INIT; \
5439 SD_INIT_NAME(sd, type); \
5440 sd->private = &tl->data; \
5445 #ifdef CONFIG_SCHED_SMT
5446 SD_INIT_FUNC(SIBLING
)
5448 #ifdef CONFIG_SCHED_MC
5451 #ifdef CONFIG_SCHED_BOOK
5455 static int default_relax_domain_level
= -1;
5456 int sched_domain_level_max
;
5458 static int __init
setup_relax_domain_level(char *str
)
5460 if (kstrtoint(str
, 0, &default_relax_domain_level
))
5461 pr_warn("Unable to set relax_domain_level\n");
5465 __setup("relax_domain_level=", setup_relax_domain_level
);
5467 static void set_domain_attribute(struct sched_domain
*sd
,
5468 struct sched_domain_attr
*attr
)
5472 if (!attr
|| attr
->relax_domain_level
< 0) {
5473 if (default_relax_domain_level
< 0)
5476 request
= default_relax_domain_level
;
5478 request
= attr
->relax_domain_level
;
5479 if (request
< sd
->level
) {
5480 /* turn off idle balance on this domain */
5481 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5483 /* turn on idle balance on this domain */
5484 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5488 static void __sdt_free(const struct cpumask
*cpu_map
);
5489 static int __sdt_alloc(const struct cpumask
*cpu_map
);
5491 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
5492 const struct cpumask
*cpu_map
)
5496 if (!atomic_read(&d
->rd
->refcount
))
5497 free_rootdomain(&d
->rd
->rcu
); /* fall through */
5499 free_percpu(d
->sd
); /* fall through */
5501 __sdt_free(cpu_map
); /* fall through */
5507 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
5508 const struct cpumask
*cpu_map
)
5510 memset(d
, 0, sizeof(*d
));
5512 if (__sdt_alloc(cpu_map
))
5513 return sa_sd_storage
;
5514 d
->sd
= alloc_percpu(struct sched_domain
*);
5516 return sa_sd_storage
;
5517 d
->rd
= alloc_rootdomain();
5520 return sa_rootdomain
;
5524 * NULL the sd_data elements we've used to build the sched_domain and
5525 * sched_group structure so that the subsequent __free_domain_allocs()
5526 * will not free the data we're using.
5528 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
5530 struct sd_data
*sdd
= sd
->private;
5532 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
5533 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
5535 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
5536 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
5538 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
5539 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
5542 #ifdef CONFIG_SCHED_SMT
5543 static const struct cpumask
*cpu_smt_mask(int cpu
)
5545 return topology_thread_cpumask(cpu
);
5550 * Topology list, bottom-up.
5552 static struct sched_domain_topology_level default_topology
[] = {
5553 #ifdef CONFIG_SCHED_SMT
5554 { sd_init_SIBLING
, cpu_smt_mask
, },
5556 #ifdef CONFIG_SCHED_MC
5557 { sd_init_MC
, cpu_coregroup_mask
, },
5559 #ifdef CONFIG_SCHED_BOOK
5560 { sd_init_BOOK
, cpu_book_mask
, },
5562 { sd_init_CPU
, cpu_cpu_mask
, },
5566 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
5568 #define for_each_sd_topology(tl) \
5569 for (tl = sched_domain_topology; tl->init; tl++)
5573 static int sched_domains_numa_levels
;
5574 static int *sched_domains_numa_distance
;
5575 static struct cpumask
***sched_domains_numa_masks
;
5576 static int sched_domains_curr_level
;
5578 static inline int sd_local_flags(int level
)
5580 if (sched_domains_numa_distance
[level
] > RECLAIM_DISTANCE
)
5583 return SD_BALANCE_EXEC
| SD_BALANCE_FORK
| SD_WAKE_AFFINE
;
5586 static struct sched_domain
*
5587 sd_numa_init(struct sched_domain_topology_level
*tl
, int cpu
)
5589 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
5590 int level
= tl
->numa_level
;
5591 int sd_weight
= cpumask_weight(
5592 sched_domains_numa_masks
[level
][cpu_to_node(cpu
)]);
5594 *sd
= (struct sched_domain
){
5595 .min_interval
= sd_weight
,
5596 .max_interval
= 2*sd_weight
,
5598 .imbalance_pct
= 125,
5599 .cache_nice_tries
= 2,
5606 .flags
= 1*SD_LOAD_BALANCE
5607 | 1*SD_BALANCE_NEWIDLE
5612 | 0*SD_SHARE_CPUPOWER
5613 | 0*SD_SHARE_PKG_RESOURCES
5615 | 0*SD_PREFER_SIBLING
5616 | sd_local_flags(level
)
5618 .last_balance
= jiffies
,
5619 .balance_interval
= sd_weight
,
5621 SD_INIT_NAME(sd
, NUMA
);
5622 sd
->private = &tl
->data
;
5625 * Ugly hack to pass state to sd_numa_mask()...
5627 sched_domains_curr_level
= tl
->numa_level
;
5632 static const struct cpumask
*sd_numa_mask(int cpu
)
5634 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
5637 static void sched_numa_warn(const char *str
)
5639 static int done
= false;
5647 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
5649 for (i
= 0; i
< nr_node_ids
; i
++) {
5650 printk(KERN_WARNING
" ");
5651 for (j
= 0; j
< nr_node_ids
; j
++)
5652 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
5653 printk(KERN_CONT
"\n");
5655 printk(KERN_WARNING
"\n");
5658 static bool find_numa_distance(int distance
)
5662 if (distance
== node_distance(0, 0))
5665 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5666 if (sched_domains_numa_distance
[i
] == distance
)
5673 static void sched_init_numa(void)
5675 int next_distance
, curr_distance
= node_distance(0, 0);
5676 struct sched_domain_topology_level
*tl
;
5680 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
5681 if (!sched_domains_numa_distance
)
5685 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
5686 * unique distances in the node_distance() table.
5688 * Assumes node_distance(0,j) includes all distances in
5689 * node_distance(i,j) in order to avoid cubic time.
5691 next_distance
= curr_distance
;
5692 for (i
= 0; i
< nr_node_ids
; i
++) {
5693 for (j
= 0; j
< nr_node_ids
; j
++) {
5694 for (k
= 0; k
< nr_node_ids
; k
++) {
5695 int distance
= node_distance(i
, k
);
5697 if (distance
> curr_distance
&&
5698 (distance
< next_distance
||
5699 next_distance
== curr_distance
))
5700 next_distance
= distance
;
5703 * While not a strong assumption it would be nice to know
5704 * about cases where if node A is connected to B, B is not
5705 * equally connected to A.
5707 if (sched_debug() && node_distance(k
, i
) != distance
)
5708 sched_numa_warn("Node-distance not symmetric");
5710 if (sched_debug() && i
&& !find_numa_distance(distance
))
5711 sched_numa_warn("Node-0 not representative");
5713 if (next_distance
!= curr_distance
) {
5714 sched_domains_numa_distance
[level
++] = next_distance
;
5715 sched_domains_numa_levels
= level
;
5716 curr_distance
= next_distance
;
5721 * In case of sched_debug() we verify the above assumption.
5727 * 'level' contains the number of unique distances, excluding the
5728 * identity distance node_distance(i,i).
5730 * The sched_domains_numa_distance[] array includes the actual distance
5735 * Here, we should temporarily reset sched_domains_numa_levels to 0.
5736 * If it fails to allocate memory for array sched_domains_numa_masks[][],
5737 * the array will contain less then 'level' members. This could be
5738 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
5739 * in other functions.
5741 * We reset it to 'level' at the end of this function.
5743 sched_domains_numa_levels
= 0;
5745 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
5746 if (!sched_domains_numa_masks
)
5750 * Now for each level, construct a mask per node which contains all
5751 * cpus of nodes that are that many hops away from us.
5753 for (i
= 0; i
< level
; i
++) {
5754 sched_domains_numa_masks
[i
] =
5755 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
5756 if (!sched_domains_numa_masks
[i
])
5759 for (j
= 0; j
< nr_node_ids
; j
++) {
5760 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
5764 sched_domains_numa_masks
[i
][j
] = mask
;
5766 for (k
= 0; k
< nr_node_ids
; k
++) {
5767 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
5770 cpumask_or(mask
, mask
, cpumask_of_node(k
));
5775 tl
= kzalloc((ARRAY_SIZE(default_topology
) + level
) *
5776 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
5781 * Copy the default topology bits..
5783 for (i
= 0; default_topology
[i
].init
; i
++)
5784 tl
[i
] = default_topology
[i
];
5787 * .. and append 'j' levels of NUMA goodness.
5789 for (j
= 0; j
< level
; i
++, j
++) {
5790 tl
[i
] = (struct sched_domain_topology_level
){
5791 .init
= sd_numa_init
,
5792 .mask
= sd_numa_mask
,
5793 .flags
= SDTL_OVERLAP
,
5798 sched_domain_topology
= tl
;
5800 sched_domains_numa_levels
= level
;
5803 static void sched_domains_numa_masks_set(int cpu
)
5806 int node
= cpu_to_node(cpu
);
5808 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5809 for (j
= 0; j
< nr_node_ids
; j
++) {
5810 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
5811 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
5816 static void sched_domains_numa_masks_clear(int cpu
)
5819 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5820 for (j
= 0; j
< nr_node_ids
; j
++)
5821 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
5826 * Update sched_domains_numa_masks[level][node] array when new cpus
5829 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
5830 unsigned long action
,
5833 int cpu
= (long)hcpu
;
5835 switch (action
& ~CPU_TASKS_FROZEN
) {
5837 sched_domains_numa_masks_set(cpu
);
5841 sched_domains_numa_masks_clear(cpu
);
5851 static inline void sched_init_numa(void)
5855 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
5856 unsigned long action
,
5861 #endif /* CONFIG_NUMA */
5863 static int __sdt_alloc(const struct cpumask
*cpu_map
)
5865 struct sched_domain_topology_level
*tl
;
5868 for_each_sd_topology(tl
) {
5869 struct sd_data
*sdd
= &tl
->data
;
5871 sdd
->sd
= alloc_percpu(struct sched_domain
*);
5875 sdd
->sg
= alloc_percpu(struct sched_group
*);
5879 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
5883 for_each_cpu(j
, cpu_map
) {
5884 struct sched_domain
*sd
;
5885 struct sched_group
*sg
;
5886 struct sched_group_power
*sgp
;
5888 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
5889 GFP_KERNEL
, cpu_to_node(j
));
5893 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
5895 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5896 GFP_KERNEL
, cpu_to_node(j
));
5902 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
5904 sgp
= kzalloc_node(sizeof(struct sched_group_power
) + cpumask_size(),
5905 GFP_KERNEL
, cpu_to_node(j
));
5909 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
5916 static void __sdt_free(const struct cpumask
*cpu_map
)
5918 struct sched_domain_topology_level
*tl
;
5921 for_each_sd_topology(tl
) {
5922 struct sd_data
*sdd
= &tl
->data
;
5924 for_each_cpu(j
, cpu_map
) {
5925 struct sched_domain
*sd
;
5928 sd
= *per_cpu_ptr(sdd
->sd
, j
);
5929 if (sd
&& (sd
->flags
& SD_OVERLAP
))
5930 free_sched_groups(sd
->groups
, 0);
5931 kfree(*per_cpu_ptr(sdd
->sd
, j
));
5935 kfree(*per_cpu_ptr(sdd
->sg
, j
));
5937 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
5939 free_percpu(sdd
->sd
);
5941 free_percpu(sdd
->sg
);
5943 free_percpu(sdd
->sgp
);
5948 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
5949 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
5950 struct sched_domain
*child
, int cpu
)
5952 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
5956 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
5958 sd
->level
= child
->level
+ 1;
5959 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
5963 set_domain_attribute(sd
, attr
);
5969 * Build sched domains for a given set of cpus and attach the sched domains
5970 * to the individual cpus
5972 static int build_sched_domains(const struct cpumask
*cpu_map
,
5973 struct sched_domain_attr
*attr
)
5975 enum s_alloc alloc_state
;
5976 struct sched_domain
*sd
;
5978 int i
, ret
= -ENOMEM
;
5980 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
5981 if (alloc_state
!= sa_rootdomain
)
5984 /* Set up domains for cpus specified by the cpu_map. */
5985 for_each_cpu(i
, cpu_map
) {
5986 struct sched_domain_topology_level
*tl
;
5989 for_each_sd_topology(tl
) {
5990 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
5991 if (tl
== sched_domain_topology
)
5992 *per_cpu_ptr(d
.sd
, i
) = sd
;
5993 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
5994 sd
->flags
|= SD_OVERLAP
;
5995 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6000 /* Build the groups for the domains */
6001 for_each_cpu(i
, cpu_map
) {
6002 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6003 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6004 if (sd
->flags
& SD_OVERLAP
) {
6005 if (build_overlap_sched_groups(sd
, i
))
6008 if (build_sched_groups(sd
, i
))
6014 /* Calculate CPU power for physical packages and nodes */
6015 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6016 if (!cpumask_test_cpu(i
, cpu_map
))
6019 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6020 claim_allocations(i
, sd
);
6021 init_sched_groups_power(i
, sd
);
6025 /* Attach the domains */
6027 for_each_cpu(i
, cpu_map
) {
6028 sd
= *per_cpu_ptr(d
.sd
, i
);
6029 cpu_attach_domain(sd
, d
.rd
, i
);
6035 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6039 static cpumask_var_t
*doms_cur
; /* current sched domains */
6040 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6041 static struct sched_domain_attr
*dattr_cur
;
6042 /* attribues of custom domains in 'doms_cur' */
6045 * Special case: If a kmalloc of a doms_cur partition (array of
6046 * cpumask) fails, then fallback to a single sched domain,
6047 * as determined by the single cpumask fallback_doms.
6049 static cpumask_var_t fallback_doms
;
6052 * arch_update_cpu_topology lets virtualized architectures update the
6053 * cpu core maps. It is supposed to return 1 if the topology changed
6054 * or 0 if it stayed the same.
6056 int __attribute__((weak
)) arch_update_cpu_topology(void)
6061 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6064 cpumask_var_t
*doms
;
6066 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6069 for (i
= 0; i
< ndoms
; i
++) {
6070 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6071 free_sched_domains(doms
, i
);
6078 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6081 for (i
= 0; i
< ndoms
; i
++)
6082 free_cpumask_var(doms
[i
]);
6087 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6088 * For now this just excludes isolated cpus, but could be used to
6089 * exclude other special cases in the future.
6091 static int init_sched_domains(const struct cpumask
*cpu_map
)
6095 arch_update_cpu_topology();
6097 doms_cur
= alloc_sched_domains(ndoms_cur
);
6099 doms_cur
= &fallback_doms
;
6100 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6101 err
= build_sched_domains(doms_cur
[0], NULL
);
6102 register_sched_domain_sysctl();
6108 * Detach sched domains from a group of cpus specified in cpu_map
6109 * These cpus will now be attached to the NULL domain
6111 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6116 for_each_cpu(i
, cpu_map
)
6117 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6121 /* handle null as "default" */
6122 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6123 struct sched_domain_attr
*new, int idx_new
)
6125 struct sched_domain_attr tmp
;
6132 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6133 new ? (new + idx_new
) : &tmp
,
6134 sizeof(struct sched_domain_attr
));
6138 * Partition sched domains as specified by the 'ndoms_new'
6139 * cpumasks in the array doms_new[] of cpumasks. This compares
6140 * doms_new[] to the current sched domain partitioning, doms_cur[].
6141 * It destroys each deleted domain and builds each new domain.
6143 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6144 * The masks don't intersect (don't overlap.) We should setup one
6145 * sched domain for each mask. CPUs not in any of the cpumasks will
6146 * not be load balanced. If the same cpumask appears both in the
6147 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6150 * The passed in 'doms_new' should be allocated using
6151 * alloc_sched_domains. This routine takes ownership of it and will
6152 * free_sched_domains it when done with it. If the caller failed the
6153 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6154 * and partition_sched_domains() will fallback to the single partition
6155 * 'fallback_doms', it also forces the domains to be rebuilt.
6157 * If doms_new == NULL it will be replaced with cpu_online_mask.
6158 * ndoms_new == 0 is a special case for destroying existing domains,
6159 * and it will not create the default domain.
6161 * Call with hotplug lock held
6163 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6164 struct sched_domain_attr
*dattr_new
)
6169 mutex_lock(&sched_domains_mutex
);
6171 /* always unregister in case we don't destroy any domains */
6172 unregister_sched_domain_sysctl();
6174 /* Let architecture update cpu core mappings. */
6175 new_topology
= arch_update_cpu_topology();
6177 n
= doms_new
? ndoms_new
: 0;
6179 /* Destroy deleted domains */
6180 for (i
= 0; i
< ndoms_cur
; i
++) {
6181 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6182 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6183 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6186 /* no match - a current sched domain not in new doms_new[] */
6187 detach_destroy_domains(doms_cur
[i
]);
6192 if (doms_new
== NULL
) {
6194 doms_new
= &fallback_doms
;
6195 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6196 WARN_ON_ONCE(dattr_new
);
6199 /* Build new domains */
6200 for (i
= 0; i
< ndoms_new
; i
++) {
6201 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
6202 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6203 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6206 /* no match - add a new doms_new */
6207 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6212 /* Remember the new sched domains */
6213 if (doms_cur
!= &fallback_doms
)
6214 free_sched_domains(doms_cur
, ndoms_cur
);
6215 kfree(dattr_cur
); /* kfree(NULL) is safe */
6216 doms_cur
= doms_new
;
6217 dattr_cur
= dattr_new
;
6218 ndoms_cur
= ndoms_new
;
6220 register_sched_domain_sysctl();
6222 mutex_unlock(&sched_domains_mutex
);
6225 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6228 * Update cpusets according to cpu_active mask. If cpusets are
6229 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6230 * around partition_sched_domains().
6232 * If we come here as part of a suspend/resume, don't touch cpusets because we
6233 * want to restore it back to its original state upon resume anyway.
6235 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6239 case CPU_ONLINE_FROZEN
:
6240 case CPU_DOWN_FAILED_FROZEN
:
6243 * num_cpus_frozen tracks how many CPUs are involved in suspend
6244 * resume sequence. As long as this is not the last online
6245 * operation in the resume sequence, just build a single sched
6246 * domain, ignoring cpusets.
6249 if (likely(num_cpus_frozen
)) {
6250 partition_sched_domains(1, NULL
, NULL
);
6255 * This is the last CPU online operation. So fall through and
6256 * restore the original sched domains by considering the
6257 * cpuset configurations.
6261 case CPU_DOWN_FAILED
:
6262 cpuset_update_active_cpus(true);
6270 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6274 case CPU_DOWN_PREPARE
:
6275 cpuset_update_active_cpus(false);
6277 case CPU_DOWN_PREPARE_FROZEN
:
6279 partition_sched_domains(1, NULL
, NULL
);
6287 void __init
sched_init_smp(void)
6289 cpumask_var_t non_isolated_cpus
;
6291 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6292 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6297 mutex_lock(&sched_domains_mutex
);
6298 init_sched_domains(cpu_active_mask
);
6299 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6300 if (cpumask_empty(non_isolated_cpus
))
6301 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6302 mutex_unlock(&sched_domains_mutex
);
6305 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
6306 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6307 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6311 /* Move init over to a non-isolated CPU */
6312 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6314 sched_init_granularity();
6315 free_cpumask_var(non_isolated_cpus
);
6317 init_sched_rt_class();
6320 void __init
sched_init_smp(void)
6322 sched_init_granularity();
6324 #endif /* CONFIG_SMP */
6326 const_debug
unsigned int sysctl_timer_migration
= 1;
6328 int in_sched_functions(unsigned long addr
)
6330 return in_lock_functions(addr
) ||
6331 (addr
>= (unsigned long)__sched_text_start
6332 && addr
< (unsigned long)__sched_text_end
);
6335 #ifdef CONFIG_CGROUP_SCHED
6337 * Default task group.
6338 * Every task in system belongs to this group at bootup.
6340 struct task_group root_task_group
;
6341 LIST_HEAD(task_groups
);
6344 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
6346 void __init
sched_init(void)
6349 unsigned long alloc_size
= 0, ptr
;
6351 #ifdef CONFIG_FAIR_GROUP_SCHED
6352 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6354 #ifdef CONFIG_RT_GROUP_SCHED
6355 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6357 #ifdef CONFIG_CPUMASK_OFFSTACK
6358 alloc_size
+= num_possible_cpus() * cpumask_size();
6361 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6363 #ifdef CONFIG_FAIR_GROUP_SCHED
6364 root_task_group
.se
= (struct sched_entity
**)ptr
;
6365 ptr
+= nr_cpu_ids
* sizeof(void **);
6367 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6368 ptr
+= nr_cpu_ids
* sizeof(void **);
6370 #endif /* CONFIG_FAIR_GROUP_SCHED */
6371 #ifdef CONFIG_RT_GROUP_SCHED
6372 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6373 ptr
+= nr_cpu_ids
* sizeof(void **);
6375 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6376 ptr
+= nr_cpu_ids
* sizeof(void **);
6378 #endif /* CONFIG_RT_GROUP_SCHED */
6379 #ifdef CONFIG_CPUMASK_OFFSTACK
6380 for_each_possible_cpu(i
) {
6381 per_cpu(load_balance_mask
, i
) = (void *)ptr
;
6382 ptr
+= cpumask_size();
6384 #endif /* CONFIG_CPUMASK_OFFSTACK */
6388 init_defrootdomain();
6391 init_rt_bandwidth(&def_rt_bandwidth
,
6392 global_rt_period(), global_rt_runtime());
6394 #ifdef CONFIG_RT_GROUP_SCHED
6395 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6396 global_rt_period(), global_rt_runtime());
6397 #endif /* CONFIG_RT_GROUP_SCHED */
6399 #ifdef CONFIG_CGROUP_SCHED
6400 list_add(&root_task_group
.list
, &task_groups
);
6401 INIT_LIST_HEAD(&root_task_group
.children
);
6402 INIT_LIST_HEAD(&root_task_group
.siblings
);
6403 autogroup_init(&init_task
);
6405 #endif /* CONFIG_CGROUP_SCHED */
6407 for_each_possible_cpu(i
) {
6411 raw_spin_lock_init(&rq
->lock
);
6413 rq
->calc_load_active
= 0;
6414 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6415 init_cfs_rq(&rq
->cfs
);
6416 init_rt_rq(&rq
->rt
, rq
);
6417 #ifdef CONFIG_FAIR_GROUP_SCHED
6418 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6419 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6421 * How much cpu bandwidth does root_task_group get?
6423 * In case of task-groups formed thr' the cgroup filesystem, it
6424 * gets 100% of the cpu resources in the system. This overall
6425 * system cpu resource is divided among the tasks of
6426 * root_task_group and its child task-groups in a fair manner,
6427 * based on each entity's (task or task-group's) weight
6428 * (se->load.weight).
6430 * In other words, if root_task_group has 10 tasks of weight
6431 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6432 * then A0's share of the cpu resource is:
6434 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6436 * We achieve this by letting root_task_group's tasks sit
6437 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6439 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6440 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6441 #endif /* CONFIG_FAIR_GROUP_SCHED */
6443 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6444 #ifdef CONFIG_RT_GROUP_SCHED
6445 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
6446 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6449 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6450 rq
->cpu_load
[j
] = 0;
6452 rq
->last_load_update_tick
= jiffies
;
6457 rq
->cpu_power
= SCHED_POWER_SCALE
;
6458 rq
->post_schedule
= 0;
6459 rq
->active_balance
= 0;
6460 rq
->next_balance
= jiffies
;
6465 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
6467 INIT_LIST_HEAD(&rq
->cfs_tasks
);
6469 rq_attach_root(rq
, &def_root_domain
);
6470 #ifdef CONFIG_NO_HZ_COMMON
6473 #ifdef CONFIG_NO_HZ_FULL
6474 rq
->last_sched_tick
= 0;
6478 atomic_set(&rq
->nr_iowait
, 0);
6481 set_load_weight(&init_task
);
6483 #ifdef CONFIG_PREEMPT_NOTIFIERS
6484 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
6487 #ifdef CONFIG_RT_MUTEXES
6488 plist_head_init(&init_task
.pi_waiters
);
6492 * The boot idle thread does lazy MMU switching as well:
6494 atomic_inc(&init_mm
.mm_count
);
6495 enter_lazy_tlb(&init_mm
, current
);
6498 * Make us the idle thread. Technically, schedule() should not be
6499 * called from this thread, however somewhere below it might be,
6500 * but because we are the idle thread, we just pick up running again
6501 * when this runqueue becomes "idle".
6503 init_idle(current
, smp_processor_id());
6505 calc_load_update
= jiffies
+ LOAD_FREQ
;
6508 * During early bootup we pretend to be a normal task:
6510 current
->sched_class
= &fair_sched_class
;
6513 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
6514 /* May be allocated at isolcpus cmdline parse time */
6515 if (cpu_isolated_map
== NULL
)
6516 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
6517 idle_thread_set_boot_cpu();
6519 init_sched_fair_class();
6521 scheduler_running
= 1;
6524 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6525 static inline int preempt_count_equals(int preempt_offset
)
6527 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
6529 return (nested
== preempt_offset
);
6532 void __might_sleep(const char *file
, int line
, int preempt_offset
)
6534 static unsigned long prev_jiffy
; /* ratelimiting */
6536 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
6537 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
6538 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
6540 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
6542 prev_jiffy
= jiffies
;
6545 "BUG: sleeping function called from invalid context at %s:%d\n",
6548 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
6549 in_atomic(), irqs_disabled(),
6550 current
->pid
, current
->comm
);
6552 debug_show_held_locks(current
);
6553 if (irqs_disabled())
6554 print_irqtrace_events(current
);
6557 EXPORT_SYMBOL(__might_sleep
);
6560 #ifdef CONFIG_MAGIC_SYSRQ
6561 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
6563 const struct sched_class
*prev_class
= p
->sched_class
;
6564 int old_prio
= p
->prio
;
6569 dequeue_task(rq
, p
, 0);
6570 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
6572 enqueue_task(rq
, p
, 0);
6573 resched_task(rq
->curr
);
6576 check_class_changed(rq
, p
, prev_class
, old_prio
);
6579 void normalize_rt_tasks(void)
6581 struct task_struct
*g
, *p
;
6582 unsigned long flags
;
6585 read_lock_irqsave(&tasklist_lock
, flags
);
6586 do_each_thread(g
, p
) {
6588 * Only normalize user tasks:
6593 p
->se
.exec_start
= 0;
6594 #ifdef CONFIG_SCHEDSTATS
6595 p
->se
.statistics
.wait_start
= 0;
6596 p
->se
.statistics
.sleep_start
= 0;
6597 p
->se
.statistics
.block_start
= 0;
6602 * Renice negative nice level userspace
6605 if (TASK_NICE(p
) < 0 && p
->mm
)
6606 set_user_nice(p
, 0);
6610 raw_spin_lock(&p
->pi_lock
);
6611 rq
= __task_rq_lock(p
);
6613 normalize_task(rq
, p
);
6615 __task_rq_unlock(rq
);
6616 raw_spin_unlock(&p
->pi_lock
);
6617 } while_each_thread(g
, p
);
6619 read_unlock_irqrestore(&tasklist_lock
, flags
);
6622 #endif /* CONFIG_MAGIC_SYSRQ */
6624 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
6626 * These functions are only useful for the IA64 MCA handling, or kdb.
6628 * They can only be called when the whole system has been
6629 * stopped - every CPU needs to be quiescent, and no scheduling
6630 * activity can take place. Using them for anything else would
6631 * be a serious bug, and as a result, they aren't even visible
6632 * under any other configuration.
6636 * curr_task - return the current task for a given cpu.
6637 * @cpu: the processor in question.
6639 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6641 struct task_struct
*curr_task(int cpu
)
6643 return cpu_curr(cpu
);
6646 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
6650 * set_curr_task - set the current task for a given cpu.
6651 * @cpu: the processor in question.
6652 * @p: the task pointer to set.
6654 * Description: This function must only be used when non-maskable interrupts
6655 * are serviced on a separate stack. It allows the architecture to switch the
6656 * notion of the current task on a cpu in a non-blocking manner. This function
6657 * must be called with all CPU's synchronized, and interrupts disabled, the
6658 * and caller must save the original value of the current task (see
6659 * curr_task() above) and restore that value before reenabling interrupts and
6660 * re-starting the system.
6662 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6664 void set_curr_task(int cpu
, struct task_struct
*p
)
6671 #ifdef CONFIG_CGROUP_SCHED
6672 /* task_group_lock serializes the addition/removal of task groups */
6673 static DEFINE_SPINLOCK(task_group_lock
);
6675 static void free_sched_group(struct task_group
*tg
)
6677 free_fair_sched_group(tg
);
6678 free_rt_sched_group(tg
);
6683 /* allocate runqueue etc for a new task group */
6684 struct task_group
*sched_create_group(struct task_group
*parent
)
6686 struct task_group
*tg
;
6688 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
6690 return ERR_PTR(-ENOMEM
);
6692 if (!alloc_fair_sched_group(tg
, parent
))
6695 if (!alloc_rt_sched_group(tg
, parent
))
6701 free_sched_group(tg
);
6702 return ERR_PTR(-ENOMEM
);
6705 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
6707 unsigned long flags
;
6709 spin_lock_irqsave(&task_group_lock
, flags
);
6710 list_add_rcu(&tg
->list
, &task_groups
);
6712 WARN_ON(!parent
); /* root should already exist */
6714 tg
->parent
= parent
;
6715 INIT_LIST_HEAD(&tg
->children
);
6716 list_add_rcu(&tg
->siblings
, &parent
->children
);
6717 spin_unlock_irqrestore(&task_group_lock
, flags
);
6720 /* rcu callback to free various structures associated with a task group */
6721 static void free_sched_group_rcu(struct rcu_head
*rhp
)
6723 /* now it should be safe to free those cfs_rqs */
6724 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
6727 /* Destroy runqueue etc associated with a task group */
6728 void sched_destroy_group(struct task_group
*tg
)
6730 /* wait for possible concurrent references to cfs_rqs complete */
6731 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
6734 void sched_offline_group(struct task_group
*tg
)
6736 unsigned long flags
;
6739 /* end participation in shares distribution */
6740 for_each_possible_cpu(i
)
6741 unregister_fair_sched_group(tg
, i
);
6743 spin_lock_irqsave(&task_group_lock
, flags
);
6744 list_del_rcu(&tg
->list
);
6745 list_del_rcu(&tg
->siblings
);
6746 spin_unlock_irqrestore(&task_group_lock
, flags
);
6749 /* change task's runqueue when it moves between groups.
6750 * The caller of this function should have put the task in its new group
6751 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
6752 * reflect its new group.
6754 void sched_move_task(struct task_struct
*tsk
)
6756 struct task_group
*tg
;
6758 unsigned long flags
;
6761 rq
= task_rq_lock(tsk
, &flags
);
6763 running
= task_current(rq
, tsk
);
6767 dequeue_task(rq
, tsk
, 0);
6768 if (unlikely(running
))
6769 tsk
->sched_class
->put_prev_task(rq
, tsk
);
6771 tg
= container_of(task_subsys_state_check(tsk
, cpu_cgroup_subsys_id
,
6772 lockdep_is_held(&tsk
->sighand
->siglock
)),
6773 struct task_group
, css
);
6774 tg
= autogroup_task_group(tsk
, tg
);
6775 tsk
->sched_task_group
= tg
;
6777 #ifdef CONFIG_FAIR_GROUP_SCHED
6778 if (tsk
->sched_class
->task_move_group
)
6779 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
6782 set_task_rq(tsk
, task_cpu(tsk
));
6784 if (unlikely(running
))
6785 tsk
->sched_class
->set_curr_task(rq
);
6787 enqueue_task(rq
, tsk
, 0);
6789 task_rq_unlock(rq
, tsk
, &flags
);
6791 #endif /* CONFIG_CGROUP_SCHED */
6793 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
6794 static unsigned long to_ratio(u64 period
, u64 runtime
)
6796 if (runtime
== RUNTIME_INF
)
6799 return div64_u64(runtime
<< 20, period
);
6803 #ifdef CONFIG_RT_GROUP_SCHED
6805 * Ensure that the real time constraints are schedulable.
6807 static DEFINE_MUTEX(rt_constraints_mutex
);
6809 /* Must be called with tasklist_lock held */
6810 static inline int tg_has_rt_tasks(struct task_group
*tg
)
6812 struct task_struct
*g
, *p
;
6814 do_each_thread(g
, p
) {
6815 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
6817 } while_each_thread(g
, p
);
6822 struct rt_schedulable_data
{
6823 struct task_group
*tg
;
6828 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
6830 struct rt_schedulable_data
*d
= data
;
6831 struct task_group
*child
;
6832 unsigned long total
, sum
= 0;
6833 u64 period
, runtime
;
6835 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
6836 runtime
= tg
->rt_bandwidth
.rt_runtime
;
6839 period
= d
->rt_period
;
6840 runtime
= d
->rt_runtime
;
6844 * Cannot have more runtime than the period.
6846 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
6850 * Ensure we don't starve existing RT tasks.
6852 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
6855 total
= to_ratio(period
, runtime
);
6858 * Nobody can have more than the global setting allows.
6860 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
6864 * The sum of our children's runtime should not exceed our own.
6866 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
6867 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
6868 runtime
= child
->rt_bandwidth
.rt_runtime
;
6870 if (child
== d
->tg
) {
6871 period
= d
->rt_period
;
6872 runtime
= d
->rt_runtime
;
6875 sum
+= to_ratio(period
, runtime
);
6884 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
6888 struct rt_schedulable_data data
= {
6890 .rt_period
= period
,
6891 .rt_runtime
= runtime
,
6895 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
6901 static int tg_set_rt_bandwidth(struct task_group
*tg
,
6902 u64 rt_period
, u64 rt_runtime
)
6906 mutex_lock(&rt_constraints_mutex
);
6907 read_lock(&tasklist_lock
);
6908 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
6912 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
6913 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
6914 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
6916 for_each_possible_cpu(i
) {
6917 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
6919 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
6920 rt_rq
->rt_runtime
= rt_runtime
;
6921 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
6923 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
6925 read_unlock(&tasklist_lock
);
6926 mutex_unlock(&rt_constraints_mutex
);
6931 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
6933 u64 rt_runtime
, rt_period
;
6935 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
6936 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
6937 if (rt_runtime_us
< 0)
6938 rt_runtime
= RUNTIME_INF
;
6940 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
6943 static long sched_group_rt_runtime(struct task_group
*tg
)
6947 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
6950 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
6951 do_div(rt_runtime_us
, NSEC_PER_USEC
);
6952 return rt_runtime_us
;
6955 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
6957 u64 rt_runtime
, rt_period
;
6959 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
6960 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
6965 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
6968 static long sched_group_rt_period(struct task_group
*tg
)
6972 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
6973 do_div(rt_period_us
, NSEC_PER_USEC
);
6974 return rt_period_us
;
6977 static int sched_rt_global_constraints(void)
6979 u64 runtime
, period
;
6982 if (sysctl_sched_rt_period
<= 0)
6985 runtime
= global_rt_runtime();
6986 period
= global_rt_period();
6989 * Sanity check on the sysctl variables.
6991 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
6994 mutex_lock(&rt_constraints_mutex
);
6995 read_lock(&tasklist_lock
);
6996 ret
= __rt_schedulable(NULL
, 0, 0);
6997 read_unlock(&tasklist_lock
);
6998 mutex_unlock(&rt_constraints_mutex
);
7003 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7005 /* Don't accept realtime tasks when there is no way for them to run */
7006 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7012 #else /* !CONFIG_RT_GROUP_SCHED */
7013 static int sched_rt_global_constraints(void)
7015 unsigned long flags
;
7018 if (sysctl_sched_rt_period
<= 0)
7022 * There's always some RT tasks in the root group
7023 * -- migration, kstopmachine etc..
7025 if (sysctl_sched_rt_runtime
== 0)
7028 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7029 for_each_possible_cpu(i
) {
7030 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7032 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7033 rt_rq
->rt_runtime
= global_rt_runtime();
7034 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7036 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7040 #endif /* CONFIG_RT_GROUP_SCHED */
7042 int sched_rr_handler(struct ctl_table
*table
, int write
,
7043 void __user
*buffer
, size_t *lenp
,
7047 static DEFINE_MUTEX(mutex
);
7050 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7051 /* make sure that internally we keep jiffies */
7052 /* also, writing zero resets timeslice to default */
7053 if (!ret
&& write
) {
7054 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7055 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7057 mutex_unlock(&mutex
);
7061 int sched_rt_handler(struct ctl_table
*table
, int write
,
7062 void __user
*buffer
, size_t *lenp
,
7066 int old_period
, old_runtime
;
7067 static DEFINE_MUTEX(mutex
);
7070 old_period
= sysctl_sched_rt_period
;
7071 old_runtime
= sysctl_sched_rt_runtime
;
7073 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7075 if (!ret
&& write
) {
7076 ret
= sched_rt_global_constraints();
7078 sysctl_sched_rt_period
= old_period
;
7079 sysctl_sched_rt_runtime
= old_runtime
;
7081 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7082 def_rt_bandwidth
.rt_period
=
7083 ns_to_ktime(global_rt_period());
7086 mutex_unlock(&mutex
);
7091 #ifdef CONFIG_CGROUP_SCHED
7093 /* return corresponding task_group object of a cgroup */
7094 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
7096 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
7097 struct task_group
, css
);
7100 static struct cgroup_subsys_state
*cpu_cgroup_css_alloc(struct cgroup
*cgrp
)
7102 struct task_group
*tg
, *parent
;
7104 if (!cgrp
->parent
) {
7105 /* This is early initialization for the top cgroup */
7106 return &root_task_group
.css
;
7109 parent
= cgroup_tg(cgrp
->parent
);
7110 tg
= sched_create_group(parent
);
7112 return ERR_PTR(-ENOMEM
);
7117 static int cpu_cgroup_css_online(struct cgroup
*cgrp
)
7119 struct task_group
*tg
= cgroup_tg(cgrp
);
7120 struct task_group
*parent
;
7125 parent
= cgroup_tg(cgrp
->parent
);
7126 sched_online_group(tg
, parent
);
7130 static void cpu_cgroup_css_free(struct cgroup
*cgrp
)
7132 struct task_group
*tg
= cgroup_tg(cgrp
);
7134 sched_destroy_group(tg
);
7137 static void cpu_cgroup_css_offline(struct cgroup
*cgrp
)
7139 struct task_group
*tg
= cgroup_tg(cgrp
);
7141 sched_offline_group(tg
);
7144 static int cpu_cgroup_can_attach(struct cgroup
*cgrp
,
7145 struct cgroup_taskset
*tset
)
7147 struct task_struct
*task
;
7149 cgroup_taskset_for_each(task
, cgrp
, tset
) {
7150 #ifdef CONFIG_RT_GROUP_SCHED
7151 if (!sched_rt_can_attach(cgroup_tg(cgrp
), task
))
7154 /* We don't support RT-tasks being in separate groups */
7155 if (task
->sched_class
!= &fair_sched_class
)
7162 static void cpu_cgroup_attach(struct cgroup
*cgrp
,
7163 struct cgroup_taskset
*tset
)
7165 struct task_struct
*task
;
7167 cgroup_taskset_for_each(task
, cgrp
, tset
)
7168 sched_move_task(task
);
7172 cpu_cgroup_exit(struct cgroup
*cgrp
, struct cgroup
*old_cgrp
,
7173 struct task_struct
*task
)
7176 * cgroup_exit() is called in the copy_process() failure path.
7177 * Ignore this case since the task hasn't ran yet, this avoids
7178 * trying to poke a half freed task state from generic code.
7180 if (!(task
->flags
& PF_EXITING
))
7183 sched_move_task(task
);
7186 #ifdef CONFIG_FAIR_GROUP_SCHED
7187 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7190 return sched_group_set_shares(cgroup_tg(cgrp
), scale_load(shareval
));
7193 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7195 struct task_group
*tg
= cgroup_tg(cgrp
);
7197 return (u64
) scale_load_down(tg
->shares
);
7200 #ifdef CONFIG_CFS_BANDWIDTH
7201 static DEFINE_MUTEX(cfs_constraints_mutex
);
7203 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7204 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7206 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7208 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7210 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7211 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7213 if (tg
== &root_task_group
)
7217 * Ensure we have at some amount of bandwidth every period. This is
7218 * to prevent reaching a state of large arrears when throttled via
7219 * entity_tick() resulting in prolonged exit starvation.
7221 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7225 * Likewise, bound things on the otherside by preventing insane quota
7226 * periods. This also allows us to normalize in computing quota
7229 if (period
> max_cfs_quota_period
)
7232 mutex_lock(&cfs_constraints_mutex
);
7233 ret
= __cfs_schedulable(tg
, period
, quota
);
7237 runtime_enabled
= quota
!= RUNTIME_INF
;
7238 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7239 account_cfs_bandwidth_used(runtime_enabled
, runtime_was_enabled
);
7240 raw_spin_lock_irq(&cfs_b
->lock
);
7241 cfs_b
->period
= ns_to_ktime(period
);
7242 cfs_b
->quota
= quota
;
7244 __refill_cfs_bandwidth_runtime(cfs_b
);
7245 /* restart the period timer (if active) to handle new period expiry */
7246 if (runtime_enabled
&& cfs_b
->timer_active
) {
7247 /* force a reprogram */
7248 cfs_b
->timer_active
= 0;
7249 __start_cfs_bandwidth(cfs_b
);
7251 raw_spin_unlock_irq(&cfs_b
->lock
);
7253 for_each_possible_cpu(i
) {
7254 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7255 struct rq
*rq
= cfs_rq
->rq
;
7257 raw_spin_lock_irq(&rq
->lock
);
7258 cfs_rq
->runtime_enabled
= runtime_enabled
;
7259 cfs_rq
->runtime_remaining
= 0;
7261 if (cfs_rq
->throttled
)
7262 unthrottle_cfs_rq(cfs_rq
);
7263 raw_spin_unlock_irq(&rq
->lock
);
7266 mutex_unlock(&cfs_constraints_mutex
);
7271 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7275 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7276 if (cfs_quota_us
< 0)
7277 quota
= RUNTIME_INF
;
7279 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7281 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7284 long tg_get_cfs_quota(struct task_group
*tg
)
7288 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7291 quota_us
= tg
->cfs_bandwidth
.quota
;
7292 do_div(quota_us
, NSEC_PER_USEC
);
7297 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7301 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7302 quota
= tg
->cfs_bandwidth
.quota
;
7304 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7307 long tg_get_cfs_period(struct task_group
*tg
)
7311 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7312 do_div(cfs_period_us
, NSEC_PER_USEC
);
7314 return cfs_period_us
;
7317 static s64
cpu_cfs_quota_read_s64(struct cgroup
*cgrp
, struct cftype
*cft
)
7319 return tg_get_cfs_quota(cgroup_tg(cgrp
));
7322 static int cpu_cfs_quota_write_s64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7325 return tg_set_cfs_quota(cgroup_tg(cgrp
), cfs_quota_us
);
7328 static u64
cpu_cfs_period_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7330 return tg_get_cfs_period(cgroup_tg(cgrp
));
7333 static int cpu_cfs_period_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7336 return tg_set_cfs_period(cgroup_tg(cgrp
), cfs_period_us
);
7339 struct cfs_schedulable_data
{
7340 struct task_group
*tg
;
7345 * normalize group quota/period to be quota/max_period
7346 * note: units are usecs
7348 static u64
normalize_cfs_quota(struct task_group
*tg
,
7349 struct cfs_schedulable_data
*d
)
7357 period
= tg_get_cfs_period(tg
);
7358 quota
= tg_get_cfs_quota(tg
);
7361 /* note: these should typically be equivalent */
7362 if (quota
== RUNTIME_INF
|| quota
== -1)
7365 return to_ratio(period
, quota
);
7368 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7370 struct cfs_schedulable_data
*d
= data
;
7371 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7372 s64 quota
= 0, parent_quota
= -1;
7375 quota
= RUNTIME_INF
;
7377 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
7379 quota
= normalize_cfs_quota(tg
, d
);
7380 parent_quota
= parent_b
->hierarchal_quota
;
7383 * ensure max(child_quota) <= parent_quota, inherit when no
7386 if (quota
== RUNTIME_INF
)
7387 quota
= parent_quota
;
7388 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
7391 cfs_b
->hierarchal_quota
= quota
;
7396 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
7399 struct cfs_schedulable_data data
= {
7405 if (quota
!= RUNTIME_INF
) {
7406 do_div(data
.period
, NSEC_PER_USEC
);
7407 do_div(data
.quota
, NSEC_PER_USEC
);
7411 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
7417 static int cpu_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
7418 struct cgroup_map_cb
*cb
)
7420 struct task_group
*tg
= cgroup_tg(cgrp
);
7421 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7423 cb
->fill(cb
, "nr_periods", cfs_b
->nr_periods
);
7424 cb
->fill(cb
, "nr_throttled", cfs_b
->nr_throttled
);
7425 cb
->fill(cb
, "throttled_time", cfs_b
->throttled_time
);
7429 #endif /* CONFIG_CFS_BANDWIDTH */
7430 #endif /* CONFIG_FAIR_GROUP_SCHED */
7432 #ifdef CONFIG_RT_GROUP_SCHED
7433 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
7436 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
7439 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
7441 return sched_group_rt_runtime(cgroup_tg(cgrp
));
7444 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
7447 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
7450 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
7452 return sched_group_rt_period(cgroup_tg(cgrp
));
7454 #endif /* CONFIG_RT_GROUP_SCHED */
7456 static struct cftype cpu_files
[] = {
7457 #ifdef CONFIG_FAIR_GROUP_SCHED
7460 .read_u64
= cpu_shares_read_u64
,
7461 .write_u64
= cpu_shares_write_u64
,
7464 #ifdef CONFIG_CFS_BANDWIDTH
7466 .name
= "cfs_quota_us",
7467 .read_s64
= cpu_cfs_quota_read_s64
,
7468 .write_s64
= cpu_cfs_quota_write_s64
,
7471 .name
= "cfs_period_us",
7472 .read_u64
= cpu_cfs_period_read_u64
,
7473 .write_u64
= cpu_cfs_period_write_u64
,
7477 .read_map
= cpu_stats_show
,
7480 #ifdef CONFIG_RT_GROUP_SCHED
7482 .name
= "rt_runtime_us",
7483 .read_s64
= cpu_rt_runtime_read
,
7484 .write_s64
= cpu_rt_runtime_write
,
7487 .name
= "rt_period_us",
7488 .read_u64
= cpu_rt_period_read_uint
,
7489 .write_u64
= cpu_rt_period_write_uint
,
7495 struct cgroup_subsys cpu_cgroup_subsys
= {
7497 .css_alloc
= cpu_cgroup_css_alloc
,
7498 .css_free
= cpu_cgroup_css_free
,
7499 .css_online
= cpu_cgroup_css_online
,
7500 .css_offline
= cpu_cgroup_css_offline
,
7501 .can_attach
= cpu_cgroup_can_attach
,
7502 .attach
= cpu_cgroup_attach
,
7503 .exit
= cpu_cgroup_exit
,
7504 .subsys_id
= cpu_cgroup_subsys_id
,
7505 .base_cftypes
= cpu_files
,
7509 #endif /* CONFIG_CGROUP_SCHED */
7511 void dump_cpu_task(int cpu
)
7513 pr_info("Task dump for CPU %d:\n", cpu
);
7514 sched_show_task(cpu_curr(cpu
));