4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <asm/mmu_context.h>
36 #include <linux/interrupt.h>
37 #include <linux/capability.h>
38 #include <linux/completion.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/debug_locks.h>
41 #include <linux/perf_event.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/proc_fs.h>
58 #include <linux/seq_file.h>
59 #include <linux/sysctl.h>
60 #include <linux/syscalls.h>
61 #include <linux/times.h>
62 #include <linux/tsacct_kern.h>
63 #include <linux/kprobes.h>
64 #include <linux/delayacct.h>
65 #include <linux/unistd.h>
66 #include <linux/pagemap.h>
67 #include <linux/hrtimer.h>
68 #include <linux/tick.h>
69 #include <linux/debugfs.h>
70 #include <linux/ctype.h>
71 #include <linux/ftrace.h>
72 #include <linux/slab.h>
73 #include <linux/init_task.h>
74 #include <linux/binfmts.h>
75 #include <linux/context_tracking.h>
77 #include <asm/switch_to.h>
79 #include <asm/irq_regs.h>
80 #include <asm/mutex.h>
81 #ifdef CONFIG_PARAVIRT
82 #include <asm/paravirt.h>
86 #include "../workqueue_internal.h"
87 #include "../smpboot.h"
89 #define CREATE_TRACE_POINTS
90 #include <trace/events/sched.h>
92 void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
95 ktime_t soft
, hard
, now
;
98 if (hrtimer_active(period_timer
))
101 now
= hrtimer_cb_get_time(period_timer
);
102 hrtimer_forward(period_timer
, now
, period
);
104 soft
= hrtimer_get_softexpires(period_timer
);
105 hard
= hrtimer_get_expires(period_timer
);
106 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
107 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
108 HRTIMER_MODE_ABS_PINNED
, 0);
112 DEFINE_MUTEX(sched_domains_mutex
);
113 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
115 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
117 void update_rq_clock(struct rq
*rq
)
121 if (rq
->skip_clock_update
> 0)
124 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
126 update_rq_clock_task(rq
, delta
);
130 * Debugging: various feature bits
133 #define SCHED_FEAT(name, enabled) \
134 (1UL << __SCHED_FEAT_##name) * enabled |
136 const_debug
unsigned int sysctl_sched_features
=
137 #include "features.h"
142 #ifdef CONFIG_SCHED_DEBUG
143 #define SCHED_FEAT(name, enabled) \
146 static const char * const sched_feat_names
[] = {
147 #include "features.h"
152 static int sched_feat_show(struct seq_file
*m
, void *v
)
156 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
157 if (!(sysctl_sched_features
& (1UL << i
)))
159 seq_printf(m
, "%s ", sched_feat_names
[i
]);
166 #ifdef HAVE_JUMP_LABEL
168 #define jump_label_key__true STATIC_KEY_INIT_TRUE
169 #define jump_label_key__false STATIC_KEY_INIT_FALSE
171 #define SCHED_FEAT(name, enabled) \
172 jump_label_key__##enabled ,
174 struct static_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
175 #include "features.h"
180 static void sched_feat_disable(int i
)
182 if (static_key_enabled(&sched_feat_keys
[i
]))
183 static_key_slow_dec(&sched_feat_keys
[i
]);
186 static void sched_feat_enable(int i
)
188 if (!static_key_enabled(&sched_feat_keys
[i
]))
189 static_key_slow_inc(&sched_feat_keys
[i
]);
192 static void sched_feat_disable(int i
) { };
193 static void sched_feat_enable(int i
) { };
194 #endif /* HAVE_JUMP_LABEL */
196 static int sched_feat_set(char *cmp
)
201 if (strncmp(cmp
, "NO_", 3) == 0) {
206 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
207 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
209 sysctl_sched_features
&= ~(1UL << i
);
210 sched_feat_disable(i
);
212 sysctl_sched_features
|= (1UL << i
);
213 sched_feat_enable(i
);
223 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
224 size_t cnt
, loff_t
*ppos
)
233 if (copy_from_user(&buf
, ubuf
, cnt
))
239 i
= sched_feat_set(cmp
);
240 if (i
== __SCHED_FEAT_NR
)
248 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
250 return single_open(filp
, sched_feat_show
, NULL
);
253 static const struct file_operations sched_feat_fops
= {
254 .open
= sched_feat_open
,
255 .write
= sched_feat_write
,
258 .release
= single_release
,
261 static __init
int sched_init_debug(void)
263 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
268 late_initcall(sched_init_debug
);
269 #endif /* CONFIG_SCHED_DEBUG */
272 * Number of tasks to iterate in a single balance run.
273 * Limited because this is done with IRQs disabled.
275 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
278 * period over which we average the RT time consumption, measured
283 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
286 * period over which we measure -rt task cpu usage in us.
289 unsigned int sysctl_sched_rt_period
= 1000000;
291 __read_mostly
int scheduler_running
;
294 * part of the period that we allow rt tasks to run in us.
297 int sysctl_sched_rt_runtime
= 950000;
302 * __task_rq_lock - lock the rq @p resides on.
304 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
309 lockdep_assert_held(&p
->pi_lock
);
313 raw_spin_lock(&rq
->lock
);
314 if (likely(rq
== task_rq(p
)))
316 raw_spin_unlock(&rq
->lock
);
321 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
323 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
324 __acquires(p
->pi_lock
)
330 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
332 raw_spin_lock(&rq
->lock
);
333 if (likely(rq
== task_rq(p
)))
335 raw_spin_unlock(&rq
->lock
);
336 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
340 static void __task_rq_unlock(struct rq
*rq
)
343 raw_spin_unlock(&rq
->lock
);
347 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
349 __releases(p
->pi_lock
)
351 raw_spin_unlock(&rq
->lock
);
352 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
356 * this_rq_lock - lock this runqueue and disable interrupts.
358 static struct rq
*this_rq_lock(void)
365 raw_spin_lock(&rq
->lock
);
370 #ifdef CONFIG_SCHED_HRTICK
372 * Use HR-timers to deliver accurate preemption points.
375 static void hrtick_clear(struct rq
*rq
)
377 if (hrtimer_active(&rq
->hrtick_timer
))
378 hrtimer_cancel(&rq
->hrtick_timer
);
382 * High-resolution timer tick.
383 * Runs from hardirq context with interrupts disabled.
385 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
387 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
389 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
391 raw_spin_lock(&rq
->lock
);
393 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
394 raw_spin_unlock(&rq
->lock
);
396 return HRTIMER_NORESTART
;
401 static int __hrtick_restart(struct rq
*rq
)
403 struct hrtimer
*timer
= &rq
->hrtick_timer
;
404 ktime_t time
= hrtimer_get_softexpires(timer
);
406 return __hrtimer_start_range_ns(timer
, time
, 0, HRTIMER_MODE_ABS_PINNED
, 0);
410 * called from hardirq (IPI) context
412 static void __hrtick_start(void *arg
)
416 raw_spin_lock(&rq
->lock
);
417 __hrtick_restart(rq
);
418 rq
->hrtick_csd_pending
= 0;
419 raw_spin_unlock(&rq
->lock
);
423 * Called to set the hrtick timer state.
425 * called with rq->lock held and irqs disabled
427 void hrtick_start(struct rq
*rq
, u64 delay
)
429 struct hrtimer
*timer
= &rq
->hrtick_timer
;
430 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
432 hrtimer_set_expires(timer
, time
);
434 if (rq
== this_rq()) {
435 __hrtick_restart(rq
);
436 } else if (!rq
->hrtick_csd_pending
) {
437 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
438 rq
->hrtick_csd_pending
= 1;
443 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
445 int cpu
= (int)(long)hcpu
;
448 case CPU_UP_CANCELED
:
449 case CPU_UP_CANCELED_FROZEN
:
450 case CPU_DOWN_PREPARE
:
451 case CPU_DOWN_PREPARE_FROZEN
:
453 case CPU_DEAD_FROZEN
:
454 hrtick_clear(cpu_rq(cpu
));
461 static __init
void init_hrtick(void)
463 hotcpu_notifier(hotplug_hrtick
, 0);
467 * Called to set the hrtick timer state.
469 * called with rq->lock held and irqs disabled
471 void hrtick_start(struct rq
*rq
, u64 delay
)
473 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
474 HRTIMER_MODE_REL_PINNED
, 0);
477 static inline void init_hrtick(void)
480 #endif /* CONFIG_SMP */
482 static void init_rq_hrtick(struct rq
*rq
)
485 rq
->hrtick_csd_pending
= 0;
487 rq
->hrtick_csd
.flags
= 0;
488 rq
->hrtick_csd
.func
= __hrtick_start
;
489 rq
->hrtick_csd
.info
= rq
;
492 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
493 rq
->hrtick_timer
.function
= hrtick
;
495 #else /* CONFIG_SCHED_HRTICK */
496 static inline void hrtick_clear(struct rq
*rq
)
500 static inline void init_rq_hrtick(struct rq
*rq
)
504 static inline void init_hrtick(void)
507 #endif /* CONFIG_SCHED_HRTICK */
510 * resched_task - mark a task 'to be rescheduled now'.
512 * On UP this means the setting of the need_resched flag, on SMP it
513 * might also involve a cross-CPU call to trigger the scheduler on
517 void resched_task(struct task_struct
*p
)
521 assert_raw_spin_locked(&task_rq(p
)->lock
);
523 if (test_tsk_need_resched(p
))
526 set_tsk_need_resched(p
);
529 if (cpu
== smp_processor_id())
532 /* NEED_RESCHED must be visible before we test polling */
534 if (!tsk_is_polling(p
))
535 smp_send_reschedule(cpu
);
538 void resched_cpu(int cpu
)
540 struct rq
*rq
= cpu_rq(cpu
);
543 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
545 resched_task(cpu_curr(cpu
));
546 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
549 #ifdef CONFIG_NO_HZ_COMMON
551 * In the semi idle case, use the nearest busy cpu for migrating timers
552 * from an idle cpu. This is good for power-savings.
554 * We don't do similar optimization for completely idle system, as
555 * selecting an idle cpu will add more delays to the timers than intended
556 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
558 int get_nohz_timer_target(void)
560 int cpu
= smp_processor_id();
562 struct sched_domain
*sd
;
565 for_each_domain(cpu
, sd
) {
566 for_each_cpu(i
, sched_domain_span(sd
)) {
578 * When add_timer_on() enqueues a timer into the timer wheel of an
579 * idle CPU then this timer might expire before the next timer event
580 * which is scheduled to wake up that CPU. In case of a completely
581 * idle system the next event might even be infinite time into the
582 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
583 * leaves the inner idle loop so the newly added timer is taken into
584 * account when the CPU goes back to idle and evaluates the timer
585 * wheel for the next timer event.
587 static void wake_up_idle_cpu(int cpu
)
589 struct rq
*rq
= cpu_rq(cpu
);
591 if (cpu
== smp_processor_id())
595 * This is safe, as this function is called with the timer
596 * wheel base lock of (cpu) held. When the CPU is on the way
597 * to idle and has not yet set rq->curr to idle then it will
598 * be serialized on the timer wheel base lock and take the new
599 * timer into account automatically.
601 if (rq
->curr
!= rq
->idle
)
605 * We can set TIF_RESCHED on the idle task of the other CPU
606 * lockless. The worst case is that the other CPU runs the
607 * idle task through an additional NOOP schedule()
609 set_tsk_need_resched(rq
->idle
);
611 /* NEED_RESCHED must be visible before we test polling */
613 if (!tsk_is_polling(rq
->idle
))
614 smp_send_reschedule(cpu
);
617 static bool wake_up_full_nohz_cpu(int cpu
)
619 if (tick_nohz_full_cpu(cpu
)) {
620 if (cpu
!= smp_processor_id() ||
621 tick_nohz_tick_stopped())
622 smp_send_reschedule(cpu
);
629 void wake_up_nohz_cpu(int cpu
)
631 if (!wake_up_full_nohz_cpu(cpu
))
632 wake_up_idle_cpu(cpu
);
635 static inline bool got_nohz_idle_kick(void)
637 int cpu
= smp_processor_id();
639 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
642 if (idle_cpu(cpu
) && !need_resched())
646 * We can't run Idle Load Balance on this CPU for this time so we
647 * cancel it and clear NOHZ_BALANCE_KICK
649 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
653 #else /* CONFIG_NO_HZ_COMMON */
655 static inline bool got_nohz_idle_kick(void)
660 #endif /* CONFIG_NO_HZ_COMMON */
662 #ifdef CONFIG_NO_HZ_FULL
663 bool sched_can_stop_tick(void)
669 /* Make sure rq->nr_running update is visible after the IPI */
672 /* More than one running task need preemption */
673 if (rq
->nr_running
> 1)
678 #endif /* CONFIG_NO_HZ_FULL */
680 void sched_avg_update(struct rq
*rq
)
682 s64 period
= sched_avg_period();
684 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
686 * Inline assembly required to prevent the compiler
687 * optimising this loop into a divmod call.
688 * See __iter_div_u64_rem() for another example of this.
690 asm("" : "+rm" (rq
->age_stamp
));
691 rq
->age_stamp
+= period
;
696 #else /* !CONFIG_SMP */
697 void resched_task(struct task_struct
*p
)
699 assert_raw_spin_locked(&task_rq(p
)->lock
);
700 set_tsk_need_resched(p
);
702 #endif /* CONFIG_SMP */
704 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
705 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
707 * Iterate task_group tree rooted at *from, calling @down when first entering a
708 * node and @up when leaving it for the final time.
710 * Caller must hold rcu_lock or sufficient equivalent.
712 int walk_tg_tree_from(struct task_group
*from
,
713 tg_visitor down
, tg_visitor up
, void *data
)
715 struct task_group
*parent
, *child
;
721 ret
= (*down
)(parent
, data
);
724 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
731 ret
= (*up
)(parent
, data
);
732 if (ret
|| parent
== from
)
736 parent
= parent
->parent
;
743 int tg_nop(struct task_group
*tg
, void *data
)
749 static void set_load_weight(struct task_struct
*p
)
751 int prio
= p
->static_prio
- MAX_RT_PRIO
;
752 struct load_weight
*load
= &p
->se
.load
;
755 * SCHED_IDLE tasks get minimal weight:
757 if (p
->policy
== SCHED_IDLE
) {
758 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
759 load
->inv_weight
= WMULT_IDLEPRIO
;
763 load
->weight
= scale_load(prio_to_weight
[prio
]);
764 load
->inv_weight
= prio_to_wmult
[prio
];
767 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
770 sched_info_queued(p
);
771 p
->sched_class
->enqueue_task(rq
, p
, flags
);
774 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
777 sched_info_dequeued(p
);
778 p
->sched_class
->dequeue_task(rq
, p
, flags
);
781 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
783 if (task_contributes_to_load(p
))
784 rq
->nr_uninterruptible
--;
786 enqueue_task(rq
, p
, flags
);
789 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
791 if (task_contributes_to_load(p
))
792 rq
->nr_uninterruptible
++;
794 dequeue_task(rq
, p
, flags
);
797 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
800 * In theory, the compile should just see 0 here, and optimize out the call
801 * to sched_rt_avg_update. But I don't trust it...
803 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
804 s64 steal
= 0, irq_delta
= 0;
806 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
807 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
810 * Since irq_time is only updated on {soft,}irq_exit, we might run into
811 * this case when a previous update_rq_clock() happened inside a
814 * When this happens, we stop ->clock_task and only update the
815 * prev_irq_time stamp to account for the part that fit, so that a next
816 * update will consume the rest. This ensures ->clock_task is
819 * It does however cause some slight miss-attribution of {soft,}irq
820 * time, a more accurate solution would be to update the irq_time using
821 * the current rq->clock timestamp, except that would require using
824 if (irq_delta
> delta
)
827 rq
->prev_irq_time
+= irq_delta
;
830 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
831 if (static_key_false((¶virt_steal_rq_enabled
))) {
834 steal
= paravirt_steal_clock(cpu_of(rq
));
835 steal
-= rq
->prev_steal_time_rq
;
837 if (unlikely(steal
> delta
))
840 st
= steal_ticks(steal
);
841 steal
= st
* TICK_NSEC
;
843 rq
->prev_steal_time_rq
+= steal
;
849 rq
->clock_task
+= delta
;
851 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
852 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
853 sched_rt_avg_update(rq
, irq_delta
+ steal
);
857 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
859 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
860 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
864 * Make it appear like a SCHED_FIFO task, its something
865 * userspace knows about and won't get confused about.
867 * Also, it will make PI more or less work without too
868 * much confusion -- but then, stop work should not
869 * rely on PI working anyway.
871 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
873 stop
->sched_class
= &stop_sched_class
;
876 cpu_rq(cpu
)->stop
= stop
;
880 * Reset it back to a normal scheduling class so that
881 * it can die in pieces.
883 old_stop
->sched_class
= &rt_sched_class
;
888 * __normal_prio - return the priority that is based on the static prio
890 static inline int __normal_prio(struct task_struct
*p
)
892 return p
->static_prio
;
896 * Calculate the expected normal priority: i.e. priority
897 * without taking RT-inheritance into account. Might be
898 * boosted by interactivity modifiers. Changes upon fork,
899 * setprio syscalls, and whenever the interactivity
900 * estimator recalculates.
902 static inline int normal_prio(struct task_struct
*p
)
906 if (task_has_rt_policy(p
))
907 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
909 prio
= __normal_prio(p
);
914 * Calculate the current priority, i.e. the priority
915 * taken into account by the scheduler. This value might
916 * be boosted by RT tasks, or might be boosted by
917 * interactivity modifiers. Will be RT if the task got
918 * RT-boosted. If not then it returns p->normal_prio.
920 static int effective_prio(struct task_struct
*p
)
922 p
->normal_prio
= normal_prio(p
);
924 * If we are RT tasks or we were boosted to RT priority,
925 * keep the priority unchanged. Otherwise, update priority
926 * to the normal priority:
928 if (!rt_prio(p
->prio
))
929 return p
->normal_prio
;
934 * task_curr - is this task currently executing on a CPU?
935 * @p: the task in question.
937 inline int task_curr(const struct task_struct
*p
)
939 return cpu_curr(task_cpu(p
)) == p
;
942 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
943 const struct sched_class
*prev_class
,
946 if (prev_class
!= p
->sched_class
) {
947 if (prev_class
->switched_from
)
948 prev_class
->switched_from(rq
, p
);
949 p
->sched_class
->switched_to(rq
, p
);
950 } else if (oldprio
!= p
->prio
)
951 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
954 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
956 const struct sched_class
*class;
958 if (p
->sched_class
== rq
->curr
->sched_class
) {
959 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
961 for_each_class(class) {
962 if (class == rq
->curr
->sched_class
)
964 if (class == p
->sched_class
) {
965 resched_task(rq
->curr
);
972 * A queue event has occurred, and we're going to schedule. In
973 * this case, we can save a useless back to back clock update.
975 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
976 rq
->skip_clock_update
= 1;
979 static ATOMIC_NOTIFIER_HEAD(task_migration_notifier
);
981 void register_task_migration_notifier(struct notifier_block
*n
)
983 atomic_notifier_chain_register(&task_migration_notifier
, n
);
987 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
989 #ifdef CONFIG_SCHED_DEBUG
991 * We should never call set_task_cpu() on a blocked task,
992 * ttwu() will sort out the placement.
994 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
995 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
997 #ifdef CONFIG_LOCKDEP
999 * The caller should hold either p->pi_lock or rq->lock, when changing
1000 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1002 * sched_move_task() holds both and thus holding either pins the cgroup,
1005 * Furthermore, all task_rq users should acquire both locks, see
1008 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1009 lockdep_is_held(&task_rq(p
)->lock
)));
1013 trace_sched_migrate_task(p
, new_cpu
);
1015 if (task_cpu(p
) != new_cpu
) {
1016 struct task_migration_notifier tmn
;
1018 if (p
->sched_class
->migrate_task_rq
)
1019 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1020 p
->se
.nr_migrations
++;
1021 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1024 tmn
.from_cpu
= task_cpu(p
);
1025 tmn
.to_cpu
= new_cpu
;
1027 atomic_notifier_call_chain(&task_migration_notifier
, 0, &tmn
);
1030 __set_task_cpu(p
, new_cpu
);
1033 struct migration_arg
{
1034 struct task_struct
*task
;
1038 static int migration_cpu_stop(void *data
);
1041 * wait_task_inactive - wait for a thread to unschedule.
1043 * If @match_state is nonzero, it's the @p->state value just checked and
1044 * not expected to change. If it changes, i.e. @p might have woken up,
1045 * then return zero. When we succeed in waiting for @p to be off its CPU,
1046 * we return a positive number (its total switch count). If a second call
1047 * a short while later returns the same number, the caller can be sure that
1048 * @p has remained unscheduled the whole time.
1050 * The caller must ensure that the task *will* unschedule sometime soon,
1051 * else this function might spin for a *long* time. This function can't
1052 * be called with interrupts off, or it may introduce deadlock with
1053 * smp_call_function() if an IPI is sent by the same process we are
1054 * waiting to become inactive.
1056 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1058 unsigned long flags
;
1065 * We do the initial early heuristics without holding
1066 * any task-queue locks at all. We'll only try to get
1067 * the runqueue lock when things look like they will
1073 * If the task is actively running on another CPU
1074 * still, just relax and busy-wait without holding
1077 * NOTE! Since we don't hold any locks, it's not
1078 * even sure that "rq" stays as the right runqueue!
1079 * But we don't care, since "task_running()" will
1080 * return false if the runqueue has changed and p
1081 * is actually now running somewhere else!
1083 while (task_running(rq
, p
)) {
1084 if (match_state
&& unlikely(p
->state
!= match_state
))
1090 * Ok, time to look more closely! We need the rq
1091 * lock now, to be *sure*. If we're wrong, we'll
1092 * just go back and repeat.
1094 rq
= task_rq_lock(p
, &flags
);
1095 trace_sched_wait_task(p
);
1096 running
= task_running(rq
, p
);
1099 if (!match_state
|| p
->state
== match_state
)
1100 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1101 task_rq_unlock(rq
, p
, &flags
);
1104 * If it changed from the expected state, bail out now.
1106 if (unlikely(!ncsw
))
1110 * Was it really running after all now that we
1111 * checked with the proper locks actually held?
1113 * Oops. Go back and try again..
1115 if (unlikely(running
)) {
1121 * It's not enough that it's not actively running,
1122 * it must be off the runqueue _entirely_, and not
1125 * So if it was still runnable (but just not actively
1126 * running right now), it's preempted, and we should
1127 * yield - it could be a while.
1129 if (unlikely(on_rq
)) {
1130 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1132 set_current_state(TASK_UNINTERRUPTIBLE
);
1133 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1138 * Ahh, all good. It wasn't running, and it wasn't
1139 * runnable, which means that it will never become
1140 * running in the future either. We're all done!
1149 * kick_process - kick a running thread to enter/exit the kernel
1150 * @p: the to-be-kicked thread
1152 * Cause a process which is running on another CPU to enter
1153 * kernel-mode, without any delay. (to get signals handled.)
1155 * NOTE: this function doesn't have to take the runqueue lock,
1156 * because all it wants to ensure is that the remote task enters
1157 * the kernel. If the IPI races and the task has been migrated
1158 * to another CPU then no harm is done and the purpose has been
1161 void kick_process(struct task_struct
*p
)
1167 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1168 smp_send_reschedule(cpu
);
1171 EXPORT_SYMBOL_GPL(kick_process
);
1172 #endif /* CONFIG_SMP */
1176 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1178 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1180 int nid
= cpu_to_node(cpu
);
1181 const struct cpumask
*nodemask
= NULL
;
1182 enum { cpuset
, possible
, fail
} state
= cpuset
;
1186 * If the node that the cpu is on has been offlined, cpu_to_node()
1187 * will return -1. There is no cpu on the node, and we should
1188 * select the cpu on the other node.
1191 nodemask
= cpumask_of_node(nid
);
1193 /* Look for allowed, online CPU in same node. */
1194 for_each_cpu(dest_cpu
, nodemask
) {
1195 if (!cpu_online(dest_cpu
))
1197 if (!cpu_active(dest_cpu
))
1199 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1205 /* Any allowed, online CPU? */
1206 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1207 if (!cpu_online(dest_cpu
))
1209 if (!cpu_active(dest_cpu
))
1216 /* No more Mr. Nice Guy. */
1217 cpuset_cpus_allowed_fallback(p
);
1222 do_set_cpus_allowed(p
, cpu_possible_mask
);
1233 if (state
!= cpuset
) {
1235 * Don't tell them about moving exiting tasks or
1236 * kernel threads (both mm NULL), since they never
1239 if (p
->mm
&& printk_ratelimit()) {
1240 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1241 task_pid_nr(p
), p
->comm
, cpu
);
1249 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1252 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
1254 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
1257 * In order not to call set_task_cpu() on a blocking task we need
1258 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1261 * Since this is common to all placement strategies, this lives here.
1263 * [ this allows ->select_task() to simply return task_cpu(p) and
1264 * not worry about this generic constraint ]
1266 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1268 cpu
= select_fallback_rq(task_cpu(p
), p
);
1273 static void update_avg(u64
*avg
, u64 sample
)
1275 s64 diff
= sample
- *avg
;
1281 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1283 #ifdef CONFIG_SCHEDSTATS
1284 struct rq
*rq
= this_rq();
1287 int this_cpu
= smp_processor_id();
1289 if (cpu
== this_cpu
) {
1290 schedstat_inc(rq
, ttwu_local
);
1291 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1293 struct sched_domain
*sd
;
1295 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1297 for_each_domain(this_cpu
, sd
) {
1298 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1299 schedstat_inc(sd
, ttwu_wake_remote
);
1306 if (wake_flags
& WF_MIGRATED
)
1307 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1309 #endif /* CONFIG_SMP */
1311 schedstat_inc(rq
, ttwu_count
);
1312 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1314 if (wake_flags
& WF_SYNC
)
1315 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1317 #endif /* CONFIG_SCHEDSTATS */
1320 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1322 activate_task(rq
, p
, en_flags
);
1325 /* if a worker is waking up, notify workqueue */
1326 if (p
->flags
& PF_WQ_WORKER
)
1327 wq_worker_waking_up(p
, cpu_of(rq
));
1331 * Mark the task runnable and perform wakeup-preemption.
1334 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1336 check_preempt_curr(rq
, p
, wake_flags
);
1337 trace_sched_wakeup(p
, true);
1339 p
->state
= TASK_RUNNING
;
1341 if (p
->sched_class
->task_woken
)
1342 p
->sched_class
->task_woken(rq
, p
);
1344 if (rq
->idle_stamp
) {
1345 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1346 u64 max
= 2*sysctl_sched_migration_cost
;
1351 update_avg(&rq
->avg_idle
, delta
);
1358 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1361 if (p
->sched_contributes_to_load
)
1362 rq
->nr_uninterruptible
--;
1365 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1366 ttwu_do_wakeup(rq
, p
, wake_flags
);
1370 * Called in case the task @p isn't fully descheduled from its runqueue,
1371 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1372 * since all we need to do is flip p->state to TASK_RUNNING, since
1373 * the task is still ->on_rq.
1375 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1380 rq
= __task_rq_lock(p
);
1382 /* check_preempt_curr() may use rq clock */
1383 update_rq_clock(rq
);
1384 ttwu_do_wakeup(rq
, p
, wake_flags
);
1387 __task_rq_unlock(rq
);
1393 static void sched_ttwu_pending(void)
1395 struct rq
*rq
= this_rq();
1396 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1397 struct task_struct
*p
;
1399 raw_spin_lock(&rq
->lock
);
1402 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1403 llist
= llist_next(llist
);
1404 ttwu_do_activate(rq
, p
, 0);
1407 raw_spin_unlock(&rq
->lock
);
1410 void scheduler_ipi(void)
1412 if (llist_empty(&this_rq()->wake_list
)
1413 && !tick_nohz_full_cpu(smp_processor_id())
1414 && !got_nohz_idle_kick())
1418 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1419 * traditionally all their work was done from the interrupt return
1420 * path. Now that we actually do some work, we need to make sure
1423 * Some archs already do call them, luckily irq_enter/exit nest
1426 * Arguably we should visit all archs and update all handlers,
1427 * however a fair share of IPIs are still resched only so this would
1428 * somewhat pessimize the simple resched case.
1431 tick_nohz_full_check();
1432 sched_ttwu_pending();
1435 * Check if someone kicked us for doing the nohz idle load balance.
1437 if (unlikely(got_nohz_idle_kick())) {
1438 this_rq()->idle_balance
= 1;
1439 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1444 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1446 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
1447 smp_send_reschedule(cpu
);
1450 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1452 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1454 #endif /* CONFIG_SMP */
1456 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1458 struct rq
*rq
= cpu_rq(cpu
);
1460 #if defined(CONFIG_SMP)
1461 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1462 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1463 ttwu_queue_remote(p
, cpu
);
1468 raw_spin_lock(&rq
->lock
);
1469 ttwu_do_activate(rq
, p
, 0);
1470 raw_spin_unlock(&rq
->lock
);
1474 * try_to_wake_up - wake up a thread
1475 * @p: the thread to be awakened
1476 * @state: the mask of task states that can be woken
1477 * @wake_flags: wake modifier flags (WF_*)
1479 * Put it on the run-queue if it's not already there. The "current"
1480 * thread is always on the run-queue (except when the actual
1481 * re-schedule is in progress), and as such you're allowed to do
1482 * the simpler "current->state = TASK_RUNNING" to mark yourself
1483 * runnable without the overhead of this.
1485 * Returns %true if @p was woken up, %false if it was already running
1486 * or @state didn't match @p's state.
1489 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1491 unsigned long flags
;
1492 int cpu
, success
= 0;
1495 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1496 if (!(p
->state
& state
))
1499 success
= 1; /* we're going to change ->state */
1502 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1507 * If the owning (remote) cpu is still in the middle of schedule() with
1508 * this task as prev, wait until its done referencing the task.
1513 * Pairs with the smp_wmb() in finish_lock_switch().
1517 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1518 p
->state
= TASK_WAKING
;
1520 if (p
->sched_class
->task_waking
)
1521 p
->sched_class
->task_waking(p
);
1523 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
1524 if (task_cpu(p
) != cpu
) {
1525 wake_flags
|= WF_MIGRATED
;
1526 set_task_cpu(p
, cpu
);
1528 #endif /* CONFIG_SMP */
1532 ttwu_stat(p
, cpu
, wake_flags
);
1534 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1540 * try_to_wake_up_local - try to wake up a local task with rq lock held
1541 * @p: the thread to be awakened
1543 * Put @p on the run-queue if it's not already there. The caller must
1544 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1547 static void try_to_wake_up_local(struct task_struct
*p
)
1549 struct rq
*rq
= task_rq(p
);
1551 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1552 WARN_ON_ONCE(p
== current
))
1555 lockdep_assert_held(&rq
->lock
);
1557 if (!raw_spin_trylock(&p
->pi_lock
)) {
1558 raw_spin_unlock(&rq
->lock
);
1559 raw_spin_lock(&p
->pi_lock
);
1560 raw_spin_lock(&rq
->lock
);
1563 if (!(p
->state
& TASK_NORMAL
))
1567 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1569 ttwu_do_wakeup(rq
, p
, 0);
1570 ttwu_stat(p
, smp_processor_id(), 0);
1572 raw_spin_unlock(&p
->pi_lock
);
1576 * wake_up_process - Wake up a specific process
1577 * @p: The process to be woken up.
1579 * Attempt to wake up the nominated process and move it to the set of runnable
1580 * processes. Returns 1 if the process was woken up, 0 if it was already
1583 * It may be assumed that this function implies a write memory barrier before
1584 * changing the task state if and only if any tasks are woken up.
1586 int wake_up_process(struct task_struct
*p
)
1588 WARN_ON(task_is_stopped_or_traced(p
));
1589 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1591 EXPORT_SYMBOL(wake_up_process
);
1593 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1595 return try_to_wake_up(p
, state
, 0);
1599 * Perform scheduler related setup for a newly forked process p.
1600 * p is forked by current.
1602 * __sched_fork() is basic setup used by init_idle() too:
1604 static void __sched_fork(struct task_struct
*p
)
1609 p
->se
.exec_start
= 0;
1610 p
->se
.sum_exec_runtime
= 0;
1611 p
->se
.prev_sum_exec_runtime
= 0;
1612 p
->se
.nr_migrations
= 0;
1614 INIT_LIST_HEAD(&p
->se
.group_node
);
1616 #ifdef CONFIG_SCHEDSTATS
1617 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1620 INIT_LIST_HEAD(&p
->rt
.run_list
);
1622 #ifdef CONFIG_PREEMPT_NOTIFIERS
1623 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1626 #ifdef CONFIG_NUMA_BALANCING
1627 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1628 p
->mm
->numa_next_scan
= jiffies
;
1629 p
->mm
->numa_next_reset
= jiffies
;
1630 p
->mm
->numa_scan_seq
= 0;
1633 p
->node_stamp
= 0ULL;
1634 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1635 p
->numa_migrate_seq
= p
->mm
? p
->mm
->numa_scan_seq
- 1 : 0;
1636 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1637 p
->numa_work
.next
= &p
->numa_work
;
1638 #endif /* CONFIG_NUMA_BALANCING */
1641 #ifdef CONFIG_NUMA_BALANCING
1642 #ifdef CONFIG_SCHED_DEBUG
1643 void set_numabalancing_state(bool enabled
)
1646 sched_feat_set("NUMA");
1648 sched_feat_set("NO_NUMA");
1651 __read_mostly
bool numabalancing_enabled
;
1653 void set_numabalancing_state(bool enabled
)
1655 numabalancing_enabled
= enabled
;
1657 #endif /* CONFIG_SCHED_DEBUG */
1658 #endif /* CONFIG_NUMA_BALANCING */
1661 * fork()/clone()-time setup:
1663 void sched_fork(struct task_struct
*p
)
1665 unsigned long flags
;
1666 int cpu
= get_cpu();
1670 * We mark the process as running here. This guarantees that
1671 * nobody will actually run it, and a signal or other external
1672 * event cannot wake it up and insert it on the runqueue either.
1674 p
->state
= TASK_RUNNING
;
1677 * Make sure we do not leak PI boosting priority to the child.
1679 p
->prio
= current
->normal_prio
;
1682 * Revert to default priority/policy on fork if requested.
1684 if (unlikely(p
->sched_reset_on_fork
)) {
1685 if (task_has_rt_policy(p
)) {
1686 p
->policy
= SCHED_NORMAL
;
1687 p
->static_prio
= NICE_TO_PRIO(0);
1689 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1690 p
->static_prio
= NICE_TO_PRIO(0);
1692 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1696 * We don't need the reset flag anymore after the fork. It has
1697 * fulfilled its duty:
1699 p
->sched_reset_on_fork
= 0;
1702 if (!rt_prio(p
->prio
))
1703 p
->sched_class
= &fair_sched_class
;
1705 if (p
->sched_class
->task_fork
)
1706 p
->sched_class
->task_fork(p
);
1709 * The child is not yet in the pid-hash so no cgroup attach races,
1710 * and the cgroup is pinned to this child due to cgroup_fork()
1711 * is ran before sched_fork().
1713 * Silence PROVE_RCU.
1715 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1716 set_task_cpu(p
, cpu
);
1717 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1719 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1720 if (likely(sched_info_on()))
1721 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1723 #if defined(CONFIG_SMP)
1726 #ifdef CONFIG_PREEMPT_COUNT
1727 /* Want to start with kernel preemption disabled. */
1728 task_thread_info(p
)->preempt_count
= 1;
1731 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1738 * wake_up_new_task - wake up a newly created task for the first time.
1740 * This function will do some initial scheduler statistics housekeeping
1741 * that must be done for every newly created context, then puts the task
1742 * on the runqueue and wakes it.
1744 void wake_up_new_task(struct task_struct
*p
)
1746 unsigned long flags
;
1749 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1752 * Fork balancing, do it here and not earlier because:
1753 * - cpus_allowed can change in the fork path
1754 * - any previously selected cpu might disappear through hotplug
1756 set_task_cpu(p
, select_task_rq(p
, SD_BALANCE_FORK
, 0));
1759 /* Initialize new task's runnable average */
1760 init_task_runnable_average(p
);
1761 rq
= __task_rq_lock(p
);
1762 activate_task(rq
, p
, 0);
1764 trace_sched_wakeup_new(p
, true);
1765 check_preempt_curr(rq
, p
, WF_FORK
);
1767 if (p
->sched_class
->task_woken
)
1768 p
->sched_class
->task_woken(rq
, p
);
1770 task_rq_unlock(rq
, p
, &flags
);
1773 #ifdef CONFIG_PREEMPT_NOTIFIERS
1776 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1777 * @notifier: notifier struct to register
1779 void preempt_notifier_register(struct preempt_notifier
*notifier
)
1781 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
1783 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
1786 * preempt_notifier_unregister - no longer interested in preemption notifications
1787 * @notifier: notifier struct to unregister
1789 * This is safe to call from within a preemption notifier.
1791 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
1793 hlist_del(¬ifier
->link
);
1795 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
1797 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1799 struct preempt_notifier
*notifier
;
1801 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
1802 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
1806 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1807 struct task_struct
*next
)
1809 struct preempt_notifier
*notifier
;
1811 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
1812 notifier
->ops
->sched_out(notifier
, next
);
1815 #else /* !CONFIG_PREEMPT_NOTIFIERS */
1817 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1822 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1823 struct task_struct
*next
)
1827 #endif /* CONFIG_PREEMPT_NOTIFIERS */
1830 * prepare_task_switch - prepare to switch tasks
1831 * @rq: the runqueue preparing to switch
1832 * @prev: the current task that is being switched out
1833 * @next: the task we are going to switch to.
1835 * This is called with the rq lock held and interrupts off. It must
1836 * be paired with a subsequent finish_task_switch after the context
1839 * prepare_task_switch sets up locking and calls architecture specific
1843 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
1844 struct task_struct
*next
)
1846 trace_sched_switch(prev
, next
);
1847 sched_info_switch(prev
, next
);
1848 perf_event_task_sched_out(prev
, next
);
1849 fire_sched_out_preempt_notifiers(prev
, next
);
1850 prepare_lock_switch(rq
, next
);
1851 prepare_arch_switch(next
);
1855 * finish_task_switch - clean up after a task-switch
1856 * @rq: runqueue associated with task-switch
1857 * @prev: the thread we just switched away from.
1859 * finish_task_switch must be called after the context switch, paired
1860 * with a prepare_task_switch call before the context switch.
1861 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1862 * and do any other architecture-specific cleanup actions.
1864 * Note that we may have delayed dropping an mm in context_switch(). If
1865 * so, we finish that here outside of the runqueue lock. (Doing it
1866 * with the lock held can cause deadlocks; see schedule() for
1869 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
1870 __releases(rq
->lock
)
1872 struct mm_struct
*mm
= rq
->prev_mm
;
1878 * A task struct has one reference for the use as "current".
1879 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1880 * schedule one last time. The schedule call will never return, and
1881 * the scheduled task must drop that reference.
1882 * The test for TASK_DEAD must occur while the runqueue locks are
1883 * still held, otherwise prev could be scheduled on another cpu, die
1884 * there before we look at prev->state, and then the reference would
1886 * Manfred Spraul <manfred@colorfullife.com>
1888 prev_state
= prev
->state
;
1889 vtime_task_switch(prev
);
1890 finish_arch_switch(prev
);
1891 perf_event_task_sched_in(prev
, current
);
1892 finish_lock_switch(rq
, prev
);
1893 finish_arch_post_lock_switch();
1895 fire_sched_in_preempt_notifiers(current
);
1898 if (unlikely(prev_state
== TASK_DEAD
)) {
1900 * Remove function-return probe instances associated with this
1901 * task and put them back on the free list.
1903 kprobe_flush_task(prev
);
1904 put_task_struct(prev
);
1907 tick_nohz_task_switch(current
);
1912 /* assumes rq->lock is held */
1913 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
1915 if (prev
->sched_class
->pre_schedule
)
1916 prev
->sched_class
->pre_schedule(rq
, prev
);
1919 /* rq->lock is NOT held, but preemption is disabled */
1920 static inline void post_schedule(struct rq
*rq
)
1922 if (rq
->post_schedule
) {
1923 unsigned long flags
;
1925 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1926 if (rq
->curr
->sched_class
->post_schedule
)
1927 rq
->curr
->sched_class
->post_schedule(rq
);
1928 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1930 rq
->post_schedule
= 0;
1936 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
1940 static inline void post_schedule(struct rq
*rq
)
1947 * schedule_tail - first thing a freshly forked thread must call.
1948 * @prev: the thread we just switched away from.
1950 asmlinkage
void schedule_tail(struct task_struct
*prev
)
1951 __releases(rq
->lock
)
1953 struct rq
*rq
= this_rq();
1955 finish_task_switch(rq
, prev
);
1958 * FIXME: do we need to worry about rq being invalidated by the
1963 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
1964 /* In this case, finish_task_switch does not reenable preemption */
1967 if (current
->set_child_tid
)
1968 put_user(task_pid_vnr(current
), current
->set_child_tid
);
1972 * context_switch - switch to the new MM and the new
1973 * thread's register state.
1976 context_switch(struct rq
*rq
, struct task_struct
*prev
,
1977 struct task_struct
*next
)
1979 struct mm_struct
*mm
, *oldmm
;
1981 prepare_task_switch(rq
, prev
, next
);
1984 oldmm
= prev
->active_mm
;
1986 * For paravirt, this is coupled with an exit in switch_to to
1987 * combine the page table reload and the switch backend into
1990 arch_start_context_switch(prev
);
1993 next
->active_mm
= oldmm
;
1994 atomic_inc(&oldmm
->mm_count
);
1995 enter_lazy_tlb(oldmm
, next
);
1997 switch_mm(oldmm
, mm
, next
);
2000 prev
->active_mm
= NULL
;
2001 rq
->prev_mm
= oldmm
;
2004 * Since the runqueue lock will be released by the next
2005 * task (which is an invalid locking op but in the case
2006 * of the scheduler it's an obvious special-case), so we
2007 * do an early lockdep release here:
2009 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2010 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2013 context_tracking_task_switch(prev
, next
);
2014 /* Here we just switch the register state and the stack. */
2015 switch_to(prev
, next
, prev
);
2019 * this_rq must be evaluated again because prev may have moved
2020 * CPUs since it called schedule(), thus the 'rq' on its stack
2021 * frame will be invalid.
2023 finish_task_switch(this_rq(), prev
);
2027 * nr_running and nr_context_switches:
2029 * externally visible scheduler statistics: current number of runnable
2030 * threads, total number of context switches performed since bootup.
2032 unsigned long nr_running(void)
2034 unsigned long i
, sum
= 0;
2036 for_each_online_cpu(i
)
2037 sum
+= cpu_rq(i
)->nr_running
;
2042 unsigned long long nr_context_switches(void)
2045 unsigned long long sum
= 0;
2047 for_each_possible_cpu(i
)
2048 sum
+= cpu_rq(i
)->nr_switches
;
2053 unsigned long nr_iowait(void)
2055 unsigned long i
, sum
= 0;
2057 for_each_possible_cpu(i
)
2058 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2063 unsigned long nr_iowait_cpu(int cpu
)
2065 struct rq
*this = cpu_rq(cpu
);
2066 return atomic_read(&this->nr_iowait
);
2072 * sched_exec - execve() is a valuable balancing opportunity, because at
2073 * this point the task has the smallest effective memory and cache footprint.
2075 void sched_exec(void)
2077 struct task_struct
*p
= current
;
2078 unsigned long flags
;
2081 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2082 dest_cpu
= p
->sched_class
->select_task_rq(p
, SD_BALANCE_EXEC
, 0);
2083 if (dest_cpu
== smp_processor_id())
2086 if (likely(cpu_active(dest_cpu
))) {
2087 struct migration_arg arg
= { p
, dest_cpu
};
2089 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2090 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2094 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2099 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2100 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2102 EXPORT_PER_CPU_SYMBOL(kstat
);
2103 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2106 * Return any ns on the sched_clock that have not yet been accounted in
2107 * @p in case that task is currently running.
2109 * Called with task_rq_lock() held on @rq.
2111 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2115 if (task_current(rq
, p
)) {
2116 update_rq_clock(rq
);
2117 ns
= rq_clock_task(rq
) - p
->se
.exec_start
;
2125 unsigned long long task_delta_exec(struct task_struct
*p
)
2127 unsigned long flags
;
2131 rq
= task_rq_lock(p
, &flags
);
2132 ns
= do_task_delta_exec(p
, rq
);
2133 task_rq_unlock(rq
, p
, &flags
);
2139 * Return accounted runtime for the task.
2140 * In case the task is currently running, return the runtime plus current's
2141 * pending runtime that have not been accounted yet.
2143 unsigned long long task_sched_runtime(struct task_struct
*p
)
2145 unsigned long flags
;
2149 rq
= task_rq_lock(p
, &flags
);
2150 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2151 task_rq_unlock(rq
, p
, &flags
);
2157 * This function gets called by the timer code, with HZ frequency.
2158 * We call it with interrupts disabled.
2160 void scheduler_tick(void)
2162 int cpu
= smp_processor_id();
2163 struct rq
*rq
= cpu_rq(cpu
);
2164 struct task_struct
*curr
= rq
->curr
;
2168 raw_spin_lock(&rq
->lock
);
2169 update_rq_clock(rq
);
2170 curr
->sched_class
->task_tick(rq
, curr
, 0);
2171 update_cpu_load_active(rq
);
2172 raw_spin_unlock(&rq
->lock
);
2174 perf_event_task_tick();
2177 rq
->idle_balance
= idle_cpu(cpu
);
2178 trigger_load_balance(rq
, cpu
);
2180 rq_last_tick_reset(rq
);
2183 #ifdef CONFIG_NO_HZ_FULL
2185 * scheduler_tick_max_deferment
2187 * Keep at least one tick per second when a single
2188 * active task is running because the scheduler doesn't
2189 * yet completely support full dynticks environment.
2191 * This makes sure that uptime, CFS vruntime, load
2192 * balancing, etc... continue to move forward, even
2193 * with a very low granularity.
2195 u64
scheduler_tick_max_deferment(void)
2197 struct rq
*rq
= this_rq();
2198 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2200 next
= rq
->last_sched_tick
+ HZ
;
2202 if (time_before_eq(next
, now
))
2205 return jiffies_to_usecs(next
- now
) * NSEC_PER_USEC
;
2209 notrace
unsigned long get_parent_ip(unsigned long addr
)
2211 if (in_lock_functions(addr
)) {
2212 addr
= CALLER_ADDR2
;
2213 if (in_lock_functions(addr
))
2214 addr
= CALLER_ADDR3
;
2219 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2220 defined(CONFIG_PREEMPT_TRACER))
2222 void __kprobes
add_preempt_count(int val
)
2224 #ifdef CONFIG_DEBUG_PREEMPT
2228 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2231 preempt_count() += val
;
2232 #ifdef CONFIG_DEBUG_PREEMPT
2234 * Spinlock count overflowing soon?
2236 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2239 if (preempt_count() == val
)
2240 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2242 EXPORT_SYMBOL(add_preempt_count
);
2244 void __kprobes
sub_preempt_count(int val
)
2246 #ifdef CONFIG_DEBUG_PREEMPT
2250 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2253 * Is the spinlock portion underflowing?
2255 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2256 !(preempt_count() & PREEMPT_MASK
)))
2260 if (preempt_count() == val
)
2261 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2262 preempt_count() -= val
;
2264 EXPORT_SYMBOL(sub_preempt_count
);
2269 * Print scheduling while atomic bug:
2271 static noinline
void __schedule_bug(struct task_struct
*prev
)
2273 if (oops_in_progress
)
2276 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2277 prev
->comm
, prev
->pid
, preempt_count());
2279 debug_show_held_locks(prev
);
2281 if (irqs_disabled())
2282 print_irqtrace_events(prev
);
2284 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2288 * Various schedule()-time debugging checks and statistics:
2290 static inline void schedule_debug(struct task_struct
*prev
)
2293 * Test if we are atomic. Since do_exit() needs to call into
2294 * schedule() atomically, we ignore that path for now.
2295 * Otherwise, whine if we are scheduling when we should not be.
2297 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
2298 __schedule_bug(prev
);
2301 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2303 schedstat_inc(this_rq(), sched_count
);
2306 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
2308 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
2309 update_rq_clock(rq
);
2310 prev
->sched_class
->put_prev_task(rq
, prev
);
2314 * Pick up the highest-prio task:
2316 static inline struct task_struct
*
2317 pick_next_task(struct rq
*rq
)
2319 const struct sched_class
*class;
2320 struct task_struct
*p
;
2323 * Optimization: we know that if all tasks are in
2324 * the fair class we can call that function directly:
2326 if (likely(rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2327 p
= fair_sched_class
.pick_next_task(rq
);
2332 for_each_class(class) {
2333 p
= class->pick_next_task(rq
);
2338 BUG(); /* the idle class will always have a runnable task */
2342 * __schedule() is the main scheduler function.
2344 * The main means of driving the scheduler and thus entering this function are:
2346 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2348 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2349 * paths. For example, see arch/x86/entry_64.S.
2351 * To drive preemption between tasks, the scheduler sets the flag in timer
2352 * interrupt handler scheduler_tick().
2354 * 3. Wakeups don't really cause entry into schedule(). They add a
2355 * task to the run-queue and that's it.
2357 * Now, if the new task added to the run-queue preempts the current
2358 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2359 * called on the nearest possible occasion:
2361 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2363 * - in syscall or exception context, at the next outmost
2364 * preempt_enable(). (this might be as soon as the wake_up()'s
2367 * - in IRQ context, return from interrupt-handler to
2368 * preemptible context
2370 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2373 * - cond_resched() call
2374 * - explicit schedule() call
2375 * - return from syscall or exception to user-space
2376 * - return from interrupt-handler to user-space
2378 static void __sched
__schedule(void)
2380 struct task_struct
*prev
, *next
;
2381 unsigned long *switch_count
;
2387 cpu
= smp_processor_id();
2389 rcu_note_context_switch(cpu
);
2392 schedule_debug(prev
);
2394 if (sched_feat(HRTICK
))
2397 raw_spin_lock_irq(&rq
->lock
);
2399 switch_count
= &prev
->nivcsw
;
2400 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2401 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2402 prev
->state
= TASK_RUNNING
;
2404 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2408 * If a worker went to sleep, notify and ask workqueue
2409 * whether it wants to wake up a task to maintain
2412 if (prev
->flags
& PF_WQ_WORKER
) {
2413 struct task_struct
*to_wakeup
;
2415 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2417 try_to_wake_up_local(to_wakeup
);
2420 switch_count
= &prev
->nvcsw
;
2423 pre_schedule(rq
, prev
);
2425 if (unlikely(!rq
->nr_running
))
2426 idle_balance(cpu
, rq
);
2428 put_prev_task(rq
, prev
);
2429 next
= pick_next_task(rq
);
2430 clear_tsk_need_resched(prev
);
2431 rq
->skip_clock_update
= 0;
2433 if (likely(prev
!= next
)) {
2438 context_switch(rq
, prev
, next
); /* unlocks the rq */
2440 * The context switch have flipped the stack from under us
2441 * and restored the local variables which were saved when
2442 * this task called schedule() in the past. prev == current
2443 * is still correct, but it can be moved to another cpu/rq.
2445 cpu
= smp_processor_id();
2448 raw_spin_unlock_irq(&rq
->lock
);
2452 sched_preempt_enable_no_resched();
2457 static inline void sched_submit_work(struct task_struct
*tsk
)
2459 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2462 * If we are going to sleep and we have plugged IO queued,
2463 * make sure to submit it to avoid deadlocks.
2465 if (blk_needs_flush_plug(tsk
))
2466 blk_schedule_flush_plug(tsk
);
2469 asmlinkage
void __sched
schedule(void)
2471 struct task_struct
*tsk
= current
;
2473 sched_submit_work(tsk
);
2476 EXPORT_SYMBOL(schedule
);
2478 #ifdef CONFIG_CONTEXT_TRACKING
2479 asmlinkage
void __sched
schedule_user(void)
2482 * If we come here after a random call to set_need_resched(),
2483 * or we have been woken up remotely but the IPI has not yet arrived,
2484 * we haven't yet exited the RCU idle mode. Do it here manually until
2485 * we find a better solution.
2494 * schedule_preempt_disabled - called with preemption disabled
2496 * Returns with preemption disabled. Note: preempt_count must be 1
2498 void __sched
schedule_preempt_disabled(void)
2500 sched_preempt_enable_no_resched();
2505 #ifdef CONFIG_PREEMPT
2507 * this is the entry point to schedule() from in-kernel preemption
2508 * off of preempt_enable. Kernel preemptions off return from interrupt
2509 * occur there and call schedule directly.
2511 asmlinkage
void __sched notrace
preempt_schedule(void)
2513 struct thread_info
*ti
= current_thread_info();
2516 * If there is a non-zero preempt_count or interrupts are disabled,
2517 * we do not want to preempt the current task. Just return..
2519 if (likely(ti
->preempt_count
|| irqs_disabled()))
2523 add_preempt_count_notrace(PREEMPT_ACTIVE
);
2525 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
2528 * Check again in case we missed a preemption opportunity
2529 * between schedule and now.
2532 } while (need_resched());
2534 EXPORT_SYMBOL(preempt_schedule
);
2537 * this is the entry point to schedule() from kernel preemption
2538 * off of irq context.
2539 * Note, that this is called and return with irqs disabled. This will
2540 * protect us against recursive calling from irq.
2542 asmlinkage
void __sched
preempt_schedule_irq(void)
2544 struct thread_info
*ti
= current_thread_info();
2545 enum ctx_state prev_state
;
2547 /* Catch callers which need to be fixed */
2548 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
2550 prev_state
= exception_enter();
2553 add_preempt_count(PREEMPT_ACTIVE
);
2556 local_irq_disable();
2557 sub_preempt_count(PREEMPT_ACTIVE
);
2560 * Check again in case we missed a preemption opportunity
2561 * between schedule and now.
2564 } while (need_resched());
2566 exception_exit(prev_state
);
2569 #endif /* CONFIG_PREEMPT */
2571 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2574 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2576 EXPORT_SYMBOL(default_wake_function
);
2579 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
2580 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
2581 * number) then we wake all the non-exclusive tasks and one exclusive task.
2583 * There are circumstances in which we can try to wake a task which has already
2584 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
2585 * zero in this (rare) case, and we handle it by continuing to scan the queue.
2587 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
2588 int nr_exclusive
, int wake_flags
, void *key
)
2590 wait_queue_t
*curr
, *next
;
2592 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
2593 unsigned flags
= curr
->flags
;
2595 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
2596 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
2602 * __wake_up - wake up threads blocked on a waitqueue.
2604 * @mode: which threads
2605 * @nr_exclusive: how many wake-one or wake-many threads to wake up
2606 * @key: is directly passed to the wakeup function
2608 * It may be assumed that this function implies a write memory barrier before
2609 * changing the task state if and only if any tasks are woken up.
2611 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
2612 int nr_exclusive
, void *key
)
2614 unsigned long flags
;
2616 spin_lock_irqsave(&q
->lock
, flags
);
2617 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
2618 spin_unlock_irqrestore(&q
->lock
, flags
);
2620 EXPORT_SYMBOL(__wake_up
);
2623 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
2625 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
, int nr
)
2627 __wake_up_common(q
, mode
, nr
, 0, NULL
);
2629 EXPORT_SYMBOL_GPL(__wake_up_locked
);
2631 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
2633 __wake_up_common(q
, mode
, 1, 0, key
);
2635 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
2638 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
2640 * @mode: which threads
2641 * @nr_exclusive: how many wake-one or wake-many threads to wake up
2642 * @key: opaque value to be passed to wakeup targets
2644 * The sync wakeup differs that the waker knows that it will schedule
2645 * away soon, so while the target thread will be woken up, it will not
2646 * be migrated to another CPU - ie. the two threads are 'synchronized'
2647 * with each other. This can prevent needless bouncing between CPUs.
2649 * On UP it can prevent extra preemption.
2651 * It may be assumed that this function implies a write memory barrier before
2652 * changing the task state if and only if any tasks are woken up.
2654 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
2655 int nr_exclusive
, void *key
)
2657 unsigned long flags
;
2658 int wake_flags
= WF_SYNC
;
2663 if (unlikely(!nr_exclusive
))
2666 spin_lock_irqsave(&q
->lock
, flags
);
2667 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
2668 spin_unlock_irqrestore(&q
->lock
, flags
);
2670 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
2673 * __wake_up_sync - see __wake_up_sync_key()
2675 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
2677 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
2679 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
2682 * complete: - signals a single thread waiting on this completion
2683 * @x: holds the state of this particular completion
2685 * This will wake up a single thread waiting on this completion. Threads will be
2686 * awakened in the same order in which they were queued.
2688 * See also complete_all(), wait_for_completion() and related routines.
2690 * It may be assumed that this function implies a write memory barrier before
2691 * changing the task state if and only if any tasks are woken up.
2693 void complete(struct completion
*x
)
2695 unsigned long flags
;
2697 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2699 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
2700 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2702 EXPORT_SYMBOL(complete
);
2705 * complete_all: - signals all threads waiting on this completion
2706 * @x: holds the state of this particular completion
2708 * This will wake up all threads waiting on this particular completion event.
2710 * It may be assumed that this function implies a write memory barrier before
2711 * changing the task state if and only if any tasks are woken up.
2713 void complete_all(struct completion
*x
)
2715 unsigned long flags
;
2717 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2718 x
->done
+= UINT_MAX
/2;
2719 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
2720 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2722 EXPORT_SYMBOL(complete_all
);
2724 static inline long __sched
2725 do_wait_for_common(struct completion
*x
,
2726 long (*action
)(long), long timeout
, int state
)
2729 DECLARE_WAITQUEUE(wait
, current
);
2731 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
2733 if (signal_pending_state(state
, current
)) {
2734 timeout
= -ERESTARTSYS
;
2737 __set_current_state(state
);
2738 spin_unlock_irq(&x
->wait
.lock
);
2739 timeout
= action(timeout
);
2740 spin_lock_irq(&x
->wait
.lock
);
2741 } while (!x
->done
&& timeout
);
2742 __remove_wait_queue(&x
->wait
, &wait
);
2747 return timeout
?: 1;
2750 static inline long __sched
2751 __wait_for_common(struct completion
*x
,
2752 long (*action
)(long), long timeout
, int state
)
2756 spin_lock_irq(&x
->wait
.lock
);
2757 timeout
= do_wait_for_common(x
, action
, timeout
, state
);
2758 spin_unlock_irq(&x
->wait
.lock
);
2763 wait_for_common(struct completion
*x
, long timeout
, int state
)
2765 return __wait_for_common(x
, schedule_timeout
, timeout
, state
);
2769 wait_for_common_io(struct completion
*x
, long timeout
, int state
)
2771 return __wait_for_common(x
, io_schedule_timeout
, timeout
, state
);
2775 * wait_for_completion: - waits for completion of a task
2776 * @x: holds the state of this particular completion
2778 * This waits to be signaled for completion of a specific task. It is NOT
2779 * interruptible and there is no timeout.
2781 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
2782 * and interrupt capability. Also see complete().
2784 void __sched
wait_for_completion(struct completion
*x
)
2786 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
2788 EXPORT_SYMBOL(wait_for_completion
);
2791 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
2792 * @x: holds the state of this particular completion
2793 * @timeout: timeout value in jiffies
2795 * This waits for either a completion of a specific task to be signaled or for a
2796 * specified timeout to expire. The timeout is in jiffies. It is not
2799 * The return value is 0 if timed out, and positive (at least 1, or number of
2800 * jiffies left till timeout) if completed.
2802 unsigned long __sched
2803 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
2805 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
2807 EXPORT_SYMBOL(wait_for_completion_timeout
);
2810 * wait_for_completion_io: - waits for completion of a task
2811 * @x: holds the state of this particular completion
2813 * This waits to be signaled for completion of a specific task. It is NOT
2814 * interruptible and there is no timeout. The caller is accounted as waiting
2817 void __sched
wait_for_completion_io(struct completion
*x
)
2819 wait_for_common_io(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
2821 EXPORT_SYMBOL(wait_for_completion_io
);
2824 * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout)
2825 * @x: holds the state of this particular completion
2826 * @timeout: timeout value in jiffies
2828 * This waits for either a completion of a specific task to be signaled or for a
2829 * specified timeout to expire. The timeout is in jiffies. It is not
2830 * interruptible. The caller is accounted as waiting for IO.
2832 * The return value is 0 if timed out, and positive (at least 1, or number of
2833 * jiffies left till timeout) if completed.
2835 unsigned long __sched
2836 wait_for_completion_io_timeout(struct completion
*x
, unsigned long timeout
)
2838 return wait_for_common_io(x
, timeout
, TASK_UNINTERRUPTIBLE
);
2840 EXPORT_SYMBOL(wait_for_completion_io_timeout
);
2843 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
2844 * @x: holds the state of this particular completion
2846 * This waits for completion of a specific task to be signaled. It is
2849 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
2851 int __sched
wait_for_completion_interruptible(struct completion
*x
)
2853 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
2854 if (t
== -ERESTARTSYS
)
2858 EXPORT_SYMBOL(wait_for_completion_interruptible
);
2861 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
2862 * @x: holds the state of this particular completion
2863 * @timeout: timeout value in jiffies
2865 * This waits for either a completion of a specific task to be signaled or for a
2866 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
2868 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
2869 * positive (at least 1, or number of jiffies left till timeout) if completed.
2872 wait_for_completion_interruptible_timeout(struct completion
*x
,
2873 unsigned long timeout
)
2875 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
2877 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
2880 * wait_for_completion_killable: - waits for completion of a task (killable)
2881 * @x: holds the state of this particular completion
2883 * This waits to be signaled for completion of a specific task. It can be
2884 * interrupted by a kill signal.
2886 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
2888 int __sched
wait_for_completion_killable(struct completion
*x
)
2890 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
2891 if (t
== -ERESTARTSYS
)
2895 EXPORT_SYMBOL(wait_for_completion_killable
);
2898 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
2899 * @x: holds the state of this particular completion
2900 * @timeout: timeout value in jiffies
2902 * This waits for either a completion of a specific task to be
2903 * signaled or for a specified timeout to expire. It can be
2904 * interrupted by a kill signal. The timeout is in jiffies.
2906 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
2907 * positive (at least 1, or number of jiffies left till timeout) if completed.
2910 wait_for_completion_killable_timeout(struct completion
*x
,
2911 unsigned long timeout
)
2913 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
2915 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
2918 * try_wait_for_completion - try to decrement a completion without blocking
2919 * @x: completion structure
2921 * Returns: 0 if a decrement cannot be done without blocking
2922 * 1 if a decrement succeeded.
2924 * If a completion is being used as a counting completion,
2925 * attempt to decrement the counter without blocking. This
2926 * enables us to avoid waiting if the resource the completion
2927 * is protecting is not available.
2929 bool try_wait_for_completion(struct completion
*x
)
2931 unsigned long flags
;
2934 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2939 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2942 EXPORT_SYMBOL(try_wait_for_completion
);
2945 * completion_done - Test to see if a completion has any waiters
2946 * @x: completion structure
2948 * Returns: 0 if there are waiters (wait_for_completion() in progress)
2949 * 1 if there are no waiters.
2952 bool completion_done(struct completion
*x
)
2954 unsigned long flags
;
2957 spin_lock_irqsave(&x
->wait
.lock
, flags
);
2960 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
2963 EXPORT_SYMBOL(completion_done
);
2966 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
2968 unsigned long flags
;
2971 init_waitqueue_entry(&wait
, current
);
2973 __set_current_state(state
);
2975 spin_lock_irqsave(&q
->lock
, flags
);
2976 __add_wait_queue(q
, &wait
);
2977 spin_unlock(&q
->lock
);
2978 timeout
= schedule_timeout(timeout
);
2979 spin_lock_irq(&q
->lock
);
2980 __remove_wait_queue(q
, &wait
);
2981 spin_unlock_irqrestore(&q
->lock
, flags
);
2986 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
2988 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
2990 EXPORT_SYMBOL(interruptible_sleep_on
);
2993 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
2995 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
2997 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
2999 void __sched
sleep_on(wait_queue_head_t
*q
)
3001 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3003 EXPORT_SYMBOL(sleep_on
);
3005 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3007 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
3009 EXPORT_SYMBOL(sleep_on_timeout
);
3011 #ifdef CONFIG_RT_MUTEXES
3014 * rt_mutex_setprio - set the current priority of a task
3016 * @prio: prio value (kernel-internal form)
3018 * This function changes the 'effective' priority of a task. It does
3019 * not touch ->normal_prio like __setscheduler().
3021 * Used by the rt_mutex code to implement priority inheritance logic.
3023 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
3025 int oldprio
, on_rq
, running
;
3027 const struct sched_class
*prev_class
;
3029 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
3031 rq
= __task_rq_lock(p
);
3034 * Idle task boosting is a nono in general. There is one
3035 * exception, when PREEMPT_RT and NOHZ is active:
3037 * The idle task calls get_next_timer_interrupt() and holds
3038 * the timer wheel base->lock on the CPU and another CPU wants
3039 * to access the timer (probably to cancel it). We can safely
3040 * ignore the boosting request, as the idle CPU runs this code
3041 * with interrupts disabled and will complete the lock
3042 * protected section without being interrupted. So there is no
3043 * real need to boost.
3045 if (unlikely(p
== rq
->idle
)) {
3046 WARN_ON(p
!= rq
->curr
);
3047 WARN_ON(p
->pi_blocked_on
);
3051 trace_sched_pi_setprio(p
, prio
);
3053 prev_class
= p
->sched_class
;
3055 running
= task_current(rq
, p
);
3057 dequeue_task(rq
, p
, 0);
3059 p
->sched_class
->put_prev_task(rq
, p
);
3062 p
->sched_class
= &rt_sched_class
;
3064 p
->sched_class
= &fair_sched_class
;
3069 p
->sched_class
->set_curr_task(rq
);
3071 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
3073 check_class_changed(rq
, p
, prev_class
, oldprio
);
3075 __task_rq_unlock(rq
);
3078 void set_user_nice(struct task_struct
*p
, long nice
)
3080 int old_prio
, delta
, on_rq
;
3081 unsigned long flags
;
3084 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
3087 * We have to be careful, if called from sys_setpriority(),
3088 * the task might be in the middle of scheduling on another CPU.
3090 rq
= task_rq_lock(p
, &flags
);
3092 * The RT priorities are set via sched_setscheduler(), but we still
3093 * allow the 'normal' nice value to be set - but as expected
3094 * it wont have any effect on scheduling until the task is
3095 * SCHED_FIFO/SCHED_RR:
3097 if (task_has_rt_policy(p
)) {
3098 p
->static_prio
= NICE_TO_PRIO(nice
);
3103 dequeue_task(rq
, p
, 0);
3105 p
->static_prio
= NICE_TO_PRIO(nice
);
3108 p
->prio
= effective_prio(p
);
3109 delta
= p
->prio
- old_prio
;
3112 enqueue_task(rq
, p
, 0);
3114 * If the task increased its priority or is running and
3115 * lowered its priority, then reschedule its CPU:
3117 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3118 resched_task(rq
->curr
);
3121 task_rq_unlock(rq
, p
, &flags
);
3123 EXPORT_SYMBOL(set_user_nice
);
3126 * can_nice - check if a task can reduce its nice value
3130 int can_nice(const struct task_struct
*p
, const int nice
)
3132 /* convert nice value [19,-20] to rlimit style value [1,40] */
3133 int nice_rlim
= 20 - nice
;
3135 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3136 capable(CAP_SYS_NICE
));
3139 #ifdef __ARCH_WANT_SYS_NICE
3142 * sys_nice - change the priority of the current process.
3143 * @increment: priority increment
3145 * sys_setpriority is a more generic, but much slower function that
3146 * does similar things.
3148 SYSCALL_DEFINE1(nice
, int, increment
)
3153 * Setpriority might change our priority at the same moment.
3154 * We don't have to worry. Conceptually one call occurs first
3155 * and we have a single winner.
3157 if (increment
< -40)
3162 nice
= TASK_NICE(current
) + increment
;
3168 if (increment
< 0 && !can_nice(current
, nice
))
3171 retval
= security_task_setnice(current
, nice
);
3175 set_user_nice(current
, nice
);
3182 * task_prio - return the priority value of a given task.
3183 * @p: the task in question.
3185 * This is the priority value as seen by users in /proc.
3186 * RT tasks are offset by -200. Normal tasks are centered
3187 * around 0, value goes from -16 to +15.
3189 int task_prio(const struct task_struct
*p
)
3191 return p
->prio
- MAX_RT_PRIO
;
3195 * task_nice - return the nice value of a given task.
3196 * @p: the task in question.
3198 int task_nice(const struct task_struct
*p
)
3200 return TASK_NICE(p
);
3202 EXPORT_SYMBOL(task_nice
);
3205 * idle_cpu - is a given cpu idle currently?
3206 * @cpu: the processor in question.
3208 int idle_cpu(int cpu
)
3210 struct rq
*rq
= cpu_rq(cpu
);
3212 if (rq
->curr
!= rq
->idle
)
3219 if (!llist_empty(&rq
->wake_list
))
3227 * idle_task - return the idle task for a given cpu.
3228 * @cpu: the processor in question.
3230 struct task_struct
*idle_task(int cpu
)
3232 return cpu_rq(cpu
)->idle
;
3236 * find_process_by_pid - find a process with a matching PID value.
3237 * @pid: the pid in question.
3239 static struct task_struct
*find_process_by_pid(pid_t pid
)
3241 return pid
? find_task_by_vpid(pid
) : current
;
3244 /* Actually do priority change: must hold rq lock. */
3246 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
3249 p
->rt_priority
= prio
;
3250 p
->normal_prio
= normal_prio(p
);
3251 /* we are holding p->pi_lock already */
3252 p
->prio
= rt_mutex_getprio(p
);
3253 if (rt_prio(p
->prio
))
3254 p
->sched_class
= &rt_sched_class
;
3256 p
->sched_class
= &fair_sched_class
;
3261 * check the target process has a UID that matches the current process's
3263 static bool check_same_owner(struct task_struct
*p
)
3265 const struct cred
*cred
= current_cred(), *pcred
;
3269 pcred
= __task_cred(p
);
3270 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3271 uid_eq(cred
->euid
, pcred
->uid
));
3276 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
3277 const struct sched_param
*param
, bool user
)
3279 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
3280 unsigned long flags
;
3281 const struct sched_class
*prev_class
;
3285 /* may grab non-irq protected spin_locks */
3286 BUG_ON(in_interrupt());
3288 /* double check policy once rq lock held */
3290 reset_on_fork
= p
->sched_reset_on_fork
;
3291 policy
= oldpolicy
= p
->policy
;
3293 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
3294 policy
&= ~SCHED_RESET_ON_FORK
;
3296 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3297 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3298 policy
!= SCHED_IDLE
)
3303 * Valid priorities for SCHED_FIFO and SCHED_RR are
3304 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3305 * SCHED_BATCH and SCHED_IDLE is 0.
3307 if (param
->sched_priority
< 0 ||
3308 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3309 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
3311 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
3315 * Allow unprivileged RT tasks to decrease priority:
3317 if (user
&& !capable(CAP_SYS_NICE
)) {
3318 if (rt_policy(policy
)) {
3319 unsigned long rlim_rtprio
=
3320 task_rlimit(p
, RLIMIT_RTPRIO
);
3322 /* can't set/change the rt policy */
3323 if (policy
!= p
->policy
&& !rlim_rtprio
)
3326 /* can't increase priority */
3327 if (param
->sched_priority
> p
->rt_priority
&&
3328 param
->sched_priority
> rlim_rtprio
)
3333 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3334 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3336 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3337 if (!can_nice(p
, TASK_NICE(p
)))
3341 /* can't change other user's priorities */
3342 if (!check_same_owner(p
))
3345 /* Normal users shall not reset the sched_reset_on_fork flag */
3346 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3351 retval
= security_task_setscheduler(p
);
3357 * make sure no PI-waiters arrive (or leave) while we are
3358 * changing the priority of the task:
3360 * To be able to change p->policy safely, the appropriate
3361 * runqueue lock must be held.
3363 rq
= task_rq_lock(p
, &flags
);
3366 * Changing the policy of the stop threads its a very bad idea
3368 if (p
== rq
->stop
) {
3369 task_rq_unlock(rq
, p
, &flags
);
3374 * If not changing anything there's no need to proceed further:
3376 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
3377 param
->sched_priority
== p
->rt_priority
))) {
3378 task_rq_unlock(rq
, p
, &flags
);
3382 #ifdef CONFIG_RT_GROUP_SCHED
3385 * Do not allow realtime tasks into groups that have no runtime
3388 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3389 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3390 !task_group_is_autogroup(task_group(p
))) {
3391 task_rq_unlock(rq
, p
, &flags
);
3397 /* recheck policy now with rq lock held */
3398 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3399 policy
= oldpolicy
= -1;
3400 task_rq_unlock(rq
, p
, &flags
);
3404 running
= task_current(rq
, p
);
3406 dequeue_task(rq
, p
, 0);
3408 p
->sched_class
->put_prev_task(rq
, p
);
3410 p
->sched_reset_on_fork
= reset_on_fork
;
3413 prev_class
= p
->sched_class
;
3414 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
3417 p
->sched_class
->set_curr_task(rq
);
3419 enqueue_task(rq
, p
, 0);
3421 check_class_changed(rq
, p
, prev_class
, oldprio
);
3422 task_rq_unlock(rq
, p
, &flags
);
3424 rt_mutex_adjust_pi(p
);
3430 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3431 * @p: the task in question.
3432 * @policy: new policy.
3433 * @param: structure containing the new RT priority.
3435 * NOTE that the task may be already dead.
3437 int sched_setscheduler(struct task_struct
*p
, int policy
,
3438 const struct sched_param
*param
)
3440 return __sched_setscheduler(p
, policy
, param
, true);
3442 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3445 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3446 * @p: the task in question.
3447 * @policy: new policy.
3448 * @param: structure containing the new RT priority.
3450 * Just like sched_setscheduler, only don't bother checking if the
3451 * current context has permission. For example, this is needed in
3452 * stop_machine(): we create temporary high priority worker threads,
3453 * but our caller might not have that capability.
3455 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3456 const struct sched_param
*param
)
3458 return __sched_setscheduler(p
, policy
, param
, false);
3462 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3464 struct sched_param lparam
;
3465 struct task_struct
*p
;
3468 if (!param
|| pid
< 0)
3470 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3475 p
= find_process_by_pid(pid
);
3477 retval
= sched_setscheduler(p
, policy
, &lparam
);
3484 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3485 * @pid: the pid in question.
3486 * @policy: new policy.
3487 * @param: structure containing the new RT priority.
3489 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3490 struct sched_param __user
*, param
)
3492 /* negative values for policy are not valid */
3496 return do_sched_setscheduler(pid
, policy
, param
);
3500 * sys_sched_setparam - set/change the RT priority of a thread
3501 * @pid: the pid in question.
3502 * @param: structure containing the new RT priority.
3504 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3506 return do_sched_setscheduler(pid
, -1, param
);
3510 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3511 * @pid: the pid in question.
3513 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3515 struct task_struct
*p
;
3523 p
= find_process_by_pid(pid
);
3525 retval
= security_task_getscheduler(p
);
3528 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3535 * sys_sched_getparam - get the RT priority of a thread
3536 * @pid: the pid in question.
3537 * @param: structure containing the RT priority.
3539 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3541 struct sched_param lp
;
3542 struct task_struct
*p
;
3545 if (!param
|| pid
< 0)
3549 p
= find_process_by_pid(pid
);
3554 retval
= security_task_getscheduler(p
);
3558 lp
.sched_priority
= p
->rt_priority
;
3562 * This one might sleep, we cannot do it with a spinlock held ...
3564 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3573 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
3575 cpumask_var_t cpus_allowed
, new_mask
;
3576 struct task_struct
*p
;
3582 p
= find_process_by_pid(pid
);
3589 /* Prevent p going away */
3593 if (p
->flags
& PF_NO_SETAFFINITY
) {
3597 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
3601 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
3603 goto out_free_cpus_allowed
;
3606 if (!check_same_owner(p
)) {
3608 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
3615 retval
= security_task_setscheduler(p
);
3619 cpuset_cpus_allowed(p
, cpus_allowed
);
3620 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
3622 retval
= set_cpus_allowed_ptr(p
, new_mask
);
3625 cpuset_cpus_allowed(p
, cpus_allowed
);
3626 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
3628 * We must have raced with a concurrent cpuset
3629 * update. Just reset the cpus_allowed to the
3630 * cpuset's cpus_allowed
3632 cpumask_copy(new_mask
, cpus_allowed
);
3637 free_cpumask_var(new_mask
);
3638 out_free_cpus_allowed
:
3639 free_cpumask_var(cpus_allowed
);
3646 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
3647 struct cpumask
*new_mask
)
3649 if (len
< cpumask_size())
3650 cpumask_clear(new_mask
);
3651 else if (len
> cpumask_size())
3652 len
= cpumask_size();
3654 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
3658 * sys_sched_setaffinity - set the cpu affinity of a process
3659 * @pid: pid of the process
3660 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3661 * @user_mask_ptr: user-space pointer to the new cpu mask
3663 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
3664 unsigned long __user
*, user_mask_ptr
)
3666 cpumask_var_t new_mask
;
3669 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
3672 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
3674 retval
= sched_setaffinity(pid
, new_mask
);
3675 free_cpumask_var(new_mask
);
3679 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
3681 struct task_struct
*p
;
3682 unsigned long flags
;
3689 p
= find_process_by_pid(pid
);
3693 retval
= security_task_getscheduler(p
);
3697 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
3698 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
3699 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
3709 * sys_sched_getaffinity - get the cpu affinity of a process
3710 * @pid: pid of the process
3711 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3712 * @user_mask_ptr: user-space pointer to hold the current cpu mask
3714 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
3715 unsigned long __user
*, user_mask_ptr
)
3720 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
3722 if (len
& (sizeof(unsigned long)-1))
3725 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
3728 ret
= sched_getaffinity(pid
, mask
);
3730 size_t retlen
= min_t(size_t, len
, cpumask_size());
3732 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
3737 free_cpumask_var(mask
);
3743 * sys_sched_yield - yield the current processor to other threads.
3745 * This function yields the current CPU to other tasks. If there are no
3746 * other threads running on this CPU then this function will return.
3748 SYSCALL_DEFINE0(sched_yield
)
3750 struct rq
*rq
= this_rq_lock();
3752 schedstat_inc(rq
, yld_count
);
3753 current
->sched_class
->yield_task(rq
);
3756 * Since we are going to call schedule() anyway, there's
3757 * no need to preempt or enable interrupts:
3759 __release(rq
->lock
);
3760 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
3761 do_raw_spin_unlock(&rq
->lock
);
3762 sched_preempt_enable_no_resched();
3769 static inline int should_resched(void)
3771 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
3774 static void __cond_resched(void)
3776 add_preempt_count(PREEMPT_ACTIVE
);
3778 sub_preempt_count(PREEMPT_ACTIVE
);
3781 int __sched
_cond_resched(void)
3783 if (should_resched()) {
3789 EXPORT_SYMBOL(_cond_resched
);
3792 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
3793 * call schedule, and on return reacquire the lock.
3795 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
3796 * operations here to prevent schedule() from being called twice (once via
3797 * spin_unlock(), once by hand).
3799 int __cond_resched_lock(spinlock_t
*lock
)
3801 int resched
= should_resched();
3804 lockdep_assert_held(lock
);
3806 if (spin_needbreak(lock
) || resched
) {
3817 EXPORT_SYMBOL(__cond_resched_lock
);
3819 int __sched
__cond_resched_softirq(void)
3821 BUG_ON(!in_softirq());
3823 if (should_resched()) {
3831 EXPORT_SYMBOL(__cond_resched_softirq
);
3834 * yield - yield the current processor to other threads.
3836 * Do not ever use this function, there's a 99% chance you're doing it wrong.
3838 * The scheduler is at all times free to pick the calling task as the most
3839 * eligible task to run, if removing the yield() call from your code breaks
3840 * it, its already broken.
3842 * Typical broken usage is:
3847 * where one assumes that yield() will let 'the other' process run that will
3848 * make event true. If the current task is a SCHED_FIFO task that will never
3849 * happen. Never use yield() as a progress guarantee!!
3851 * If you want to use yield() to wait for something, use wait_event().
3852 * If you want to use yield() to be 'nice' for others, use cond_resched().
3853 * If you still want to use yield(), do not!
3855 void __sched
yield(void)
3857 set_current_state(TASK_RUNNING
);
3860 EXPORT_SYMBOL(yield
);
3863 * yield_to - yield the current processor to another thread in
3864 * your thread group, or accelerate that thread toward the
3865 * processor it's on.
3867 * @preempt: whether task preemption is allowed or not
3869 * It's the caller's job to ensure that the target task struct
3870 * can't go away on us before we can do any checks.
3873 * true (>0) if we indeed boosted the target task.
3874 * false (0) if we failed to boost the target.
3875 * -ESRCH if there's no task to yield to.
3877 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
3879 struct task_struct
*curr
= current
;
3880 struct rq
*rq
, *p_rq
;
3881 unsigned long flags
;
3884 local_irq_save(flags
);
3890 * If we're the only runnable task on the rq and target rq also
3891 * has only one task, there's absolutely no point in yielding.
3893 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
3898 double_rq_lock(rq
, p_rq
);
3899 while (task_rq(p
) != p_rq
) {
3900 double_rq_unlock(rq
, p_rq
);
3904 if (!curr
->sched_class
->yield_to_task
)
3907 if (curr
->sched_class
!= p
->sched_class
)
3910 if (task_running(p_rq
, p
) || p
->state
)
3913 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
3915 schedstat_inc(rq
, yld_count
);
3917 * Make p's CPU reschedule; pick_next_entity takes care of
3920 if (preempt
&& rq
!= p_rq
)
3921 resched_task(p_rq
->curr
);
3925 double_rq_unlock(rq
, p_rq
);
3927 local_irq_restore(flags
);
3934 EXPORT_SYMBOL_GPL(yield_to
);
3937 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
3938 * that process accounting knows that this is a task in IO wait state.
3940 void __sched
io_schedule(void)
3942 struct rq
*rq
= raw_rq();
3944 delayacct_blkio_start();
3945 atomic_inc(&rq
->nr_iowait
);
3946 blk_flush_plug(current
);
3947 current
->in_iowait
= 1;
3949 current
->in_iowait
= 0;
3950 atomic_dec(&rq
->nr_iowait
);
3951 delayacct_blkio_end();
3953 EXPORT_SYMBOL(io_schedule
);
3955 long __sched
io_schedule_timeout(long timeout
)
3957 struct rq
*rq
= raw_rq();
3960 delayacct_blkio_start();
3961 atomic_inc(&rq
->nr_iowait
);
3962 blk_flush_plug(current
);
3963 current
->in_iowait
= 1;
3964 ret
= schedule_timeout(timeout
);
3965 current
->in_iowait
= 0;
3966 atomic_dec(&rq
->nr_iowait
);
3967 delayacct_blkio_end();
3972 * sys_sched_get_priority_max - return maximum RT priority.
3973 * @policy: scheduling class.
3975 * this syscall returns the maximum rt_priority that can be used
3976 * by a given scheduling class.
3978 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
3985 ret
= MAX_USER_RT_PRIO
-1;
3997 * sys_sched_get_priority_min - return minimum RT priority.
3998 * @policy: scheduling class.
4000 * this syscall returns the minimum rt_priority that can be used
4001 * by a given scheduling class.
4003 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4021 * sys_sched_rr_get_interval - return the default timeslice of a process.
4022 * @pid: pid of the process.
4023 * @interval: userspace pointer to the timeslice value.
4025 * this syscall writes the default timeslice value of a given process
4026 * into the user-space timespec buffer. A value of '0' means infinity.
4028 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4029 struct timespec __user
*, interval
)
4031 struct task_struct
*p
;
4032 unsigned int time_slice
;
4033 unsigned long flags
;
4043 p
= find_process_by_pid(pid
);
4047 retval
= security_task_getscheduler(p
);
4051 rq
= task_rq_lock(p
, &flags
);
4052 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4053 task_rq_unlock(rq
, p
, &flags
);
4056 jiffies_to_timespec(time_slice
, &t
);
4057 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4065 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4067 void sched_show_task(struct task_struct
*p
)
4069 unsigned long free
= 0;
4073 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4074 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4075 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4076 #if BITS_PER_LONG == 32
4077 if (state
== TASK_RUNNING
)
4078 printk(KERN_CONT
" running ");
4080 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4082 if (state
== TASK_RUNNING
)
4083 printk(KERN_CONT
" running task ");
4085 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4087 #ifdef CONFIG_DEBUG_STACK_USAGE
4088 free
= stack_not_used(p
);
4091 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4093 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4094 task_pid_nr(p
), ppid
,
4095 (unsigned long)task_thread_info(p
)->flags
);
4097 print_worker_info(KERN_INFO
, p
);
4098 show_stack(p
, NULL
);
4101 void show_state_filter(unsigned long state_filter
)
4103 struct task_struct
*g
, *p
;
4105 #if BITS_PER_LONG == 32
4107 " task PC stack pid father\n");
4110 " task PC stack pid father\n");
4113 do_each_thread(g
, p
) {
4115 * reset the NMI-timeout, listing all files on a slow
4116 * console might take a lot of time:
4118 touch_nmi_watchdog();
4119 if (!state_filter
|| (p
->state
& state_filter
))
4121 } while_each_thread(g
, p
);
4123 touch_all_softlockup_watchdogs();
4125 #ifdef CONFIG_SCHED_DEBUG
4126 sysrq_sched_debug_show();
4130 * Only show locks if all tasks are dumped:
4133 debug_show_all_locks();
4136 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
4138 idle
->sched_class
= &idle_sched_class
;
4142 * init_idle - set up an idle thread for a given CPU
4143 * @idle: task in question
4144 * @cpu: cpu the idle task belongs to
4146 * NOTE: this function does not set the idle thread's NEED_RESCHED
4147 * flag, to make booting more robust.
4149 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
4151 struct rq
*rq
= cpu_rq(cpu
);
4152 unsigned long flags
;
4154 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4157 idle
->state
= TASK_RUNNING
;
4158 idle
->se
.exec_start
= sched_clock();
4160 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4162 * We're having a chicken and egg problem, even though we are
4163 * holding rq->lock, the cpu isn't yet set to this cpu so the
4164 * lockdep check in task_group() will fail.
4166 * Similar case to sched_fork(). / Alternatively we could
4167 * use task_rq_lock() here and obtain the other rq->lock.
4172 __set_task_cpu(idle
, cpu
);
4175 rq
->curr
= rq
->idle
= idle
;
4176 #if defined(CONFIG_SMP)
4179 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4181 /* Set the preempt count _outside_ the spinlocks! */
4182 task_thread_info(idle
)->preempt_count
= 0;
4185 * The idle tasks have their own, simple scheduling class:
4187 idle
->sched_class
= &idle_sched_class
;
4188 ftrace_graph_init_idle_task(idle
, cpu
);
4189 vtime_init_idle(idle
, cpu
);
4190 #if defined(CONFIG_SMP)
4191 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4196 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4198 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4199 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4201 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4202 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4206 * This is how migration works:
4208 * 1) we invoke migration_cpu_stop() on the target CPU using
4210 * 2) stopper starts to run (implicitly forcing the migrated thread
4212 * 3) it checks whether the migrated task is still in the wrong runqueue.
4213 * 4) if it's in the wrong runqueue then the migration thread removes
4214 * it and puts it into the right queue.
4215 * 5) stopper completes and stop_one_cpu() returns and the migration
4220 * Change a given task's CPU affinity. Migrate the thread to a
4221 * proper CPU and schedule it away if the CPU it's executing on
4222 * is removed from the allowed bitmask.
4224 * NOTE: the caller must have a valid reference to the task, the
4225 * task must not exit() & deallocate itself prematurely. The
4226 * call is not atomic; no spinlocks may be held.
4228 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4230 unsigned long flags
;
4232 unsigned int dest_cpu
;
4235 rq
= task_rq_lock(p
, &flags
);
4237 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4240 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4245 do_set_cpus_allowed(p
, new_mask
);
4247 /* Can the task run on the task's current CPU? If so, we're done */
4248 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4251 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4253 struct migration_arg arg
= { p
, dest_cpu
};
4254 /* Need help from migration thread: drop lock and wait. */
4255 task_rq_unlock(rq
, p
, &flags
);
4256 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4257 tlb_migrate_finish(p
->mm
);
4261 task_rq_unlock(rq
, p
, &flags
);
4265 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4268 * Move (not current) task off this cpu, onto dest cpu. We're doing
4269 * this because either it can't run here any more (set_cpus_allowed()
4270 * away from this CPU, or CPU going down), or because we're
4271 * attempting to rebalance this task on exec (sched_exec).
4273 * So we race with normal scheduler movements, but that's OK, as long
4274 * as the task is no longer on this CPU.
4276 * Returns non-zero if task was successfully migrated.
4278 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4280 struct rq
*rq_dest
, *rq_src
;
4283 if (unlikely(!cpu_active(dest_cpu
)))
4286 rq_src
= cpu_rq(src_cpu
);
4287 rq_dest
= cpu_rq(dest_cpu
);
4289 raw_spin_lock(&p
->pi_lock
);
4290 double_rq_lock(rq_src
, rq_dest
);
4291 /* Already moved. */
4292 if (task_cpu(p
) != src_cpu
)
4294 /* Affinity changed (again). */
4295 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4299 * If we're not on a rq, the next wake-up will ensure we're
4303 dequeue_task(rq_src
, p
, 0);
4304 set_task_cpu(p
, dest_cpu
);
4305 enqueue_task(rq_dest
, p
, 0);
4306 check_preempt_curr(rq_dest
, p
, 0);
4311 double_rq_unlock(rq_src
, rq_dest
);
4312 raw_spin_unlock(&p
->pi_lock
);
4317 * migration_cpu_stop - this will be executed by a highprio stopper thread
4318 * and performs thread migration by bumping thread off CPU then
4319 * 'pushing' onto another runqueue.
4321 static int migration_cpu_stop(void *data
)
4323 struct migration_arg
*arg
= data
;
4326 * The original target cpu might have gone down and we might
4327 * be on another cpu but it doesn't matter.
4329 local_irq_disable();
4330 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4335 #ifdef CONFIG_HOTPLUG_CPU
4338 * Ensures that the idle task is using init_mm right before its cpu goes
4341 void idle_task_exit(void)
4343 struct mm_struct
*mm
= current
->active_mm
;
4345 BUG_ON(cpu_online(smp_processor_id()));
4348 switch_mm(mm
, &init_mm
, current
);
4353 * Since this CPU is going 'away' for a while, fold any nr_active delta
4354 * we might have. Assumes we're called after migrate_tasks() so that the
4355 * nr_active count is stable.
4357 * Also see the comment "Global load-average calculations".
4359 static void calc_load_migrate(struct rq
*rq
)
4361 long delta
= calc_load_fold_active(rq
);
4363 atomic_long_add(delta
, &calc_load_tasks
);
4367 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4368 * try_to_wake_up()->select_task_rq().
4370 * Called with rq->lock held even though we'er in stop_machine() and
4371 * there's no concurrency possible, we hold the required locks anyway
4372 * because of lock validation efforts.
4374 static void migrate_tasks(unsigned int dead_cpu
)
4376 struct rq
*rq
= cpu_rq(dead_cpu
);
4377 struct task_struct
*next
, *stop
= rq
->stop
;
4381 * Fudge the rq selection such that the below task selection loop
4382 * doesn't get stuck on the currently eligible stop task.
4384 * We're currently inside stop_machine() and the rq is either stuck
4385 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4386 * either way we should never end up calling schedule() until we're
4392 * put_prev_task() and pick_next_task() sched
4393 * class method both need to have an up-to-date
4394 * value of rq->clock[_task]
4396 update_rq_clock(rq
);
4400 * There's this thread running, bail when that's the only
4403 if (rq
->nr_running
== 1)
4406 next
= pick_next_task(rq
);
4408 next
->sched_class
->put_prev_task(rq
, next
);
4410 /* Find suitable destination for @next, with force if needed. */
4411 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
4412 raw_spin_unlock(&rq
->lock
);
4414 __migrate_task(next
, dead_cpu
, dest_cpu
);
4416 raw_spin_lock(&rq
->lock
);
4422 #endif /* CONFIG_HOTPLUG_CPU */
4424 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4426 static struct ctl_table sd_ctl_dir
[] = {
4428 .procname
= "sched_domain",
4434 static struct ctl_table sd_ctl_root
[] = {
4436 .procname
= "kernel",
4438 .child
= sd_ctl_dir
,
4443 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
4445 struct ctl_table
*entry
=
4446 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
4451 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
4453 struct ctl_table
*entry
;
4456 * In the intermediate directories, both the child directory and
4457 * procname are dynamically allocated and could fail but the mode
4458 * will always be set. In the lowest directory the names are
4459 * static strings and all have proc handlers.
4461 for (entry
= *tablep
; entry
->mode
; entry
++) {
4463 sd_free_ctl_entry(&entry
->child
);
4464 if (entry
->proc_handler
== NULL
)
4465 kfree(entry
->procname
);
4472 static int min_load_idx
= 0;
4473 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
4476 set_table_entry(struct ctl_table
*entry
,
4477 const char *procname
, void *data
, int maxlen
,
4478 umode_t mode
, proc_handler
*proc_handler
,
4481 entry
->procname
= procname
;
4483 entry
->maxlen
= maxlen
;
4485 entry
->proc_handler
= proc_handler
;
4488 entry
->extra1
= &min_load_idx
;
4489 entry
->extra2
= &max_load_idx
;
4493 static struct ctl_table
*
4494 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
4496 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
4501 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
4502 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4503 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
4504 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4505 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
4506 sizeof(int), 0644, proc_dointvec_minmax
, true);
4507 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
4508 sizeof(int), 0644, proc_dointvec_minmax
, true);
4509 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
4510 sizeof(int), 0644, proc_dointvec_minmax
, true);
4511 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
4512 sizeof(int), 0644, proc_dointvec_minmax
, true);
4513 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
4514 sizeof(int), 0644, proc_dointvec_minmax
, true);
4515 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
4516 sizeof(int), 0644, proc_dointvec_minmax
, false);
4517 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
4518 sizeof(int), 0644, proc_dointvec_minmax
, false);
4519 set_table_entry(&table
[9], "cache_nice_tries",
4520 &sd
->cache_nice_tries
,
4521 sizeof(int), 0644, proc_dointvec_minmax
, false);
4522 set_table_entry(&table
[10], "flags", &sd
->flags
,
4523 sizeof(int), 0644, proc_dointvec_minmax
, false);
4524 set_table_entry(&table
[11], "name", sd
->name
,
4525 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
4526 /* &table[12] is terminator */
4531 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
4533 struct ctl_table
*entry
, *table
;
4534 struct sched_domain
*sd
;
4535 int domain_num
= 0, i
;
4538 for_each_domain(cpu
, sd
)
4540 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
4545 for_each_domain(cpu
, sd
) {
4546 snprintf(buf
, 32, "domain%d", i
);
4547 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4549 entry
->child
= sd_alloc_ctl_domain_table(sd
);
4556 static struct ctl_table_header
*sd_sysctl_header
;
4557 static void register_sched_domain_sysctl(void)
4559 int i
, cpu_num
= num_possible_cpus();
4560 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
4563 WARN_ON(sd_ctl_dir
[0].child
);
4564 sd_ctl_dir
[0].child
= entry
;
4569 for_each_possible_cpu(i
) {
4570 snprintf(buf
, 32, "cpu%d", i
);
4571 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4573 entry
->child
= sd_alloc_ctl_cpu_table(i
);
4577 WARN_ON(sd_sysctl_header
);
4578 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
4581 /* may be called multiple times per register */
4582 static void unregister_sched_domain_sysctl(void)
4584 if (sd_sysctl_header
)
4585 unregister_sysctl_table(sd_sysctl_header
);
4586 sd_sysctl_header
= NULL
;
4587 if (sd_ctl_dir
[0].child
)
4588 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
4591 static void register_sched_domain_sysctl(void)
4594 static void unregister_sched_domain_sysctl(void)
4599 static void set_rq_online(struct rq
*rq
)
4602 const struct sched_class
*class;
4604 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
4607 for_each_class(class) {
4608 if (class->rq_online
)
4609 class->rq_online(rq
);
4614 static void set_rq_offline(struct rq
*rq
)
4617 const struct sched_class
*class;
4619 for_each_class(class) {
4620 if (class->rq_offline
)
4621 class->rq_offline(rq
);
4624 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
4630 * migration_call - callback that gets triggered when a CPU is added.
4631 * Here we can start up the necessary migration thread for the new CPU.
4633 static int __cpuinit
4634 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
4636 int cpu
= (long)hcpu
;
4637 unsigned long flags
;
4638 struct rq
*rq
= cpu_rq(cpu
);
4640 switch (action
& ~CPU_TASKS_FROZEN
) {
4642 case CPU_UP_PREPARE
:
4643 rq
->calc_load_update
= calc_load_update
;
4647 /* Update our root-domain */
4648 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4650 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
4654 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4657 #ifdef CONFIG_HOTPLUG_CPU
4659 sched_ttwu_pending();
4660 /* Update our root-domain */
4661 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4663 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
4667 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
4668 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4672 calc_load_migrate(rq
);
4677 update_max_interval();
4683 * Register at high priority so that task migration (migrate_all_tasks)
4684 * happens before everything else. This has to be lower priority than
4685 * the notifier in the perf_event subsystem, though.
4687 static struct notifier_block __cpuinitdata migration_notifier
= {
4688 .notifier_call
= migration_call
,
4689 .priority
= CPU_PRI_MIGRATION
,
4692 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
4693 unsigned long action
, void *hcpu
)
4695 switch (action
& ~CPU_TASKS_FROZEN
) {
4697 case CPU_DOWN_FAILED
:
4698 set_cpu_active((long)hcpu
, true);
4705 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
4706 unsigned long action
, void *hcpu
)
4708 switch (action
& ~CPU_TASKS_FROZEN
) {
4709 case CPU_DOWN_PREPARE
:
4710 set_cpu_active((long)hcpu
, false);
4717 static int __init
migration_init(void)
4719 void *cpu
= (void *)(long)smp_processor_id();
4722 /* Initialize migration for the boot CPU */
4723 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
4724 BUG_ON(err
== NOTIFY_BAD
);
4725 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
4726 register_cpu_notifier(&migration_notifier
);
4728 /* Register cpu active notifiers */
4729 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
4730 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
4734 early_initcall(migration_init
);
4739 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
4741 #ifdef CONFIG_SCHED_DEBUG
4743 static __read_mostly
int sched_debug_enabled
;
4745 static int __init
sched_debug_setup(char *str
)
4747 sched_debug_enabled
= 1;
4751 early_param("sched_debug", sched_debug_setup
);
4753 static inline bool sched_debug(void)
4755 return sched_debug_enabled
;
4758 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
4759 struct cpumask
*groupmask
)
4761 struct sched_group
*group
= sd
->groups
;
4764 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
4765 cpumask_clear(groupmask
);
4767 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
4769 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
4770 printk("does not load-balance\n");
4772 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
4777 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
4779 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
4780 printk(KERN_ERR
"ERROR: domain->span does not contain "
4783 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
4784 printk(KERN_ERR
"ERROR: domain->groups does not contain"
4788 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
4792 printk(KERN_ERR
"ERROR: group is NULL\n");
4797 * Even though we initialize ->power to something semi-sane,
4798 * we leave power_orig unset. This allows us to detect if
4799 * domain iteration is still funny without causing /0 traps.
4801 if (!group
->sgp
->power_orig
) {
4802 printk(KERN_CONT
"\n");
4803 printk(KERN_ERR
"ERROR: domain->cpu_power not "
4808 if (!cpumask_weight(sched_group_cpus(group
))) {
4809 printk(KERN_CONT
"\n");
4810 printk(KERN_ERR
"ERROR: empty group\n");
4814 if (!(sd
->flags
& SD_OVERLAP
) &&
4815 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
4816 printk(KERN_CONT
"\n");
4817 printk(KERN_ERR
"ERROR: repeated CPUs\n");
4821 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
4823 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
4825 printk(KERN_CONT
" %s", str
);
4826 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
4827 printk(KERN_CONT
" (cpu_power = %d)",
4831 group
= group
->next
;
4832 } while (group
!= sd
->groups
);
4833 printk(KERN_CONT
"\n");
4835 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
4836 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
4839 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
4840 printk(KERN_ERR
"ERROR: parent span is not a superset "
4841 "of domain->span\n");
4845 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
4849 if (!sched_debug_enabled
)
4853 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
4857 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
4860 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
4868 #else /* !CONFIG_SCHED_DEBUG */
4869 # define sched_domain_debug(sd, cpu) do { } while (0)
4870 static inline bool sched_debug(void)
4874 #endif /* CONFIG_SCHED_DEBUG */
4876 static int sd_degenerate(struct sched_domain
*sd
)
4878 if (cpumask_weight(sched_domain_span(sd
)) == 1)
4881 /* Following flags need at least 2 groups */
4882 if (sd
->flags
& (SD_LOAD_BALANCE
|
4883 SD_BALANCE_NEWIDLE
|
4887 SD_SHARE_PKG_RESOURCES
)) {
4888 if (sd
->groups
!= sd
->groups
->next
)
4892 /* Following flags don't use groups */
4893 if (sd
->flags
& (SD_WAKE_AFFINE
))
4900 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
4902 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
4904 if (sd_degenerate(parent
))
4907 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
4910 /* Flags needing groups don't count if only 1 group in parent */
4911 if (parent
->groups
== parent
->groups
->next
) {
4912 pflags
&= ~(SD_LOAD_BALANCE
|
4913 SD_BALANCE_NEWIDLE
|
4917 SD_SHARE_PKG_RESOURCES
);
4918 if (nr_node_ids
== 1)
4919 pflags
&= ~SD_SERIALIZE
;
4921 if (~cflags
& pflags
)
4927 static void free_rootdomain(struct rcu_head
*rcu
)
4929 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
4931 cpupri_cleanup(&rd
->cpupri
);
4932 free_cpumask_var(rd
->rto_mask
);
4933 free_cpumask_var(rd
->online
);
4934 free_cpumask_var(rd
->span
);
4938 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
4940 struct root_domain
*old_rd
= NULL
;
4941 unsigned long flags
;
4943 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4948 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
4951 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
4954 * If we dont want to free the old_rt yet then
4955 * set old_rd to NULL to skip the freeing later
4958 if (!atomic_dec_and_test(&old_rd
->refcount
))
4962 atomic_inc(&rd
->refcount
);
4965 cpumask_set_cpu(rq
->cpu
, rd
->span
);
4966 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
4969 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4972 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
4975 static int init_rootdomain(struct root_domain
*rd
)
4977 memset(rd
, 0, sizeof(*rd
));
4979 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
4981 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
4983 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
4986 if (cpupri_init(&rd
->cpupri
) != 0)
4991 free_cpumask_var(rd
->rto_mask
);
4993 free_cpumask_var(rd
->online
);
4995 free_cpumask_var(rd
->span
);
5001 * By default the system creates a single root-domain with all cpus as
5002 * members (mimicking the global state we have today).
5004 struct root_domain def_root_domain
;
5006 static void init_defrootdomain(void)
5008 init_rootdomain(&def_root_domain
);
5010 atomic_set(&def_root_domain
.refcount
, 1);
5013 static struct root_domain
*alloc_rootdomain(void)
5015 struct root_domain
*rd
;
5017 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5021 if (init_rootdomain(rd
) != 0) {
5029 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
5031 struct sched_group
*tmp
, *first
;
5040 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
5045 } while (sg
!= first
);
5048 static void free_sched_domain(struct rcu_head
*rcu
)
5050 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5053 * If its an overlapping domain it has private groups, iterate and
5056 if (sd
->flags
& SD_OVERLAP
) {
5057 free_sched_groups(sd
->groups
, 1);
5058 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5059 kfree(sd
->groups
->sgp
);
5065 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5067 call_rcu(&sd
->rcu
, free_sched_domain
);
5070 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5072 for (; sd
; sd
= sd
->parent
)
5073 destroy_sched_domain(sd
, cpu
);
5077 * Keep a special pointer to the highest sched_domain that has
5078 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5079 * allows us to avoid some pointer chasing select_idle_sibling().
5081 * Also keep a unique ID per domain (we use the first cpu number in
5082 * the cpumask of the domain), this allows us to quickly tell if
5083 * two cpus are in the same cache domain, see cpus_share_cache().
5085 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5086 DEFINE_PER_CPU(int, sd_llc_id
);
5088 static void update_top_cache_domain(int cpu
)
5090 struct sched_domain
*sd
;
5093 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5095 id
= cpumask_first(sched_domain_span(sd
));
5097 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5098 per_cpu(sd_llc_id
, cpu
) = id
;
5102 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5103 * hold the hotplug lock.
5106 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5108 struct rq
*rq
= cpu_rq(cpu
);
5109 struct sched_domain
*tmp
;
5111 /* Remove the sched domains which do not contribute to scheduling. */
5112 for (tmp
= sd
; tmp
; ) {
5113 struct sched_domain
*parent
= tmp
->parent
;
5117 if (sd_parent_degenerate(tmp
, parent
)) {
5118 tmp
->parent
= parent
->parent
;
5120 parent
->parent
->child
= tmp
;
5121 destroy_sched_domain(parent
, cpu
);
5126 if (sd
&& sd_degenerate(sd
)) {
5129 destroy_sched_domain(tmp
, cpu
);
5134 sched_domain_debug(sd
, cpu
);
5136 rq_attach_root(rq
, rd
);
5138 rcu_assign_pointer(rq
->sd
, sd
);
5139 destroy_sched_domains(tmp
, cpu
);
5141 update_top_cache_domain(cpu
);
5144 /* cpus with isolated domains */
5145 static cpumask_var_t cpu_isolated_map
;
5147 /* Setup the mask of cpus configured for isolated domains */
5148 static int __init
isolated_cpu_setup(char *str
)
5150 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5151 cpulist_parse(str
, cpu_isolated_map
);
5155 __setup("isolcpus=", isolated_cpu_setup
);
5157 static const struct cpumask
*cpu_cpu_mask(int cpu
)
5159 return cpumask_of_node(cpu_to_node(cpu
));
5163 struct sched_domain
**__percpu sd
;
5164 struct sched_group
**__percpu sg
;
5165 struct sched_group_power
**__percpu sgp
;
5169 struct sched_domain
** __percpu sd
;
5170 struct root_domain
*rd
;
5180 struct sched_domain_topology_level
;
5182 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
5183 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
5185 #define SDTL_OVERLAP 0x01
5187 struct sched_domain_topology_level
{
5188 sched_domain_init_f init
;
5189 sched_domain_mask_f mask
;
5192 struct sd_data data
;
5196 * Build an iteration mask that can exclude certain CPUs from the upwards
5199 * Asymmetric node setups can result in situations where the domain tree is of
5200 * unequal depth, make sure to skip domains that already cover the entire
5203 * In that case build_sched_domains() will have terminated the iteration early
5204 * and our sibling sd spans will be empty. Domains should always include the
5205 * cpu they're built on, so check that.
5208 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5210 const struct cpumask
*span
= sched_domain_span(sd
);
5211 struct sd_data
*sdd
= sd
->private;
5212 struct sched_domain
*sibling
;
5215 for_each_cpu(i
, span
) {
5216 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5217 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5220 cpumask_set_cpu(i
, sched_group_mask(sg
));
5225 * Return the canonical balance cpu for this group, this is the first cpu
5226 * of this group that's also in the iteration mask.
5228 int group_balance_cpu(struct sched_group
*sg
)
5230 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5234 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5236 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5237 const struct cpumask
*span
= sched_domain_span(sd
);
5238 struct cpumask
*covered
= sched_domains_tmpmask
;
5239 struct sd_data
*sdd
= sd
->private;
5240 struct sched_domain
*child
;
5243 cpumask_clear(covered
);
5245 for_each_cpu(i
, span
) {
5246 struct cpumask
*sg_span
;
5248 if (cpumask_test_cpu(i
, covered
))
5251 child
= *per_cpu_ptr(sdd
->sd
, i
);
5253 /* See the comment near build_group_mask(). */
5254 if (!cpumask_test_cpu(i
, sched_domain_span(child
)))
5257 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5258 GFP_KERNEL
, cpu_to_node(cpu
));
5263 sg_span
= sched_group_cpus(sg
);
5265 child
= child
->child
;
5266 cpumask_copy(sg_span
, sched_domain_span(child
));
5268 cpumask_set_cpu(i
, sg_span
);
5270 cpumask_or(covered
, covered
, sg_span
);
5272 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, i
);
5273 if (atomic_inc_return(&sg
->sgp
->ref
) == 1)
5274 build_group_mask(sd
, sg
);
5277 * Initialize sgp->power such that even if we mess up the
5278 * domains and no possible iteration will get us here, we won't
5281 sg
->sgp
->power
= SCHED_POWER_SCALE
* cpumask_weight(sg_span
);
5284 * Make sure the first group of this domain contains the
5285 * canonical balance cpu. Otherwise the sched_domain iteration
5286 * breaks. See update_sg_lb_stats().
5288 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5289 group_balance_cpu(sg
) == cpu
)
5299 sd
->groups
= groups
;
5304 free_sched_groups(first
, 0);
5309 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5311 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5312 struct sched_domain
*child
= sd
->child
;
5315 cpu
= cpumask_first(sched_domain_span(child
));
5318 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5319 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
5320 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
5327 * build_sched_groups will build a circular linked list of the groups
5328 * covered by the given span, and will set each group's ->cpumask correctly,
5329 * and ->cpu_power to 0.
5331 * Assumes the sched_domain tree is fully constructed
5334 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5336 struct sched_group
*first
= NULL
, *last
= NULL
;
5337 struct sd_data
*sdd
= sd
->private;
5338 const struct cpumask
*span
= sched_domain_span(sd
);
5339 struct cpumask
*covered
;
5342 get_group(cpu
, sdd
, &sd
->groups
);
5343 atomic_inc(&sd
->groups
->ref
);
5345 if (cpu
!= cpumask_first(span
))
5348 lockdep_assert_held(&sched_domains_mutex
);
5349 covered
= sched_domains_tmpmask
;
5351 cpumask_clear(covered
);
5353 for_each_cpu(i
, span
) {
5354 struct sched_group
*sg
;
5357 if (cpumask_test_cpu(i
, covered
))
5360 group
= get_group(i
, sdd
, &sg
);
5361 cpumask_clear(sched_group_cpus(sg
));
5363 cpumask_setall(sched_group_mask(sg
));
5365 for_each_cpu(j
, span
) {
5366 if (get_group(j
, sdd
, NULL
) != group
)
5369 cpumask_set_cpu(j
, covered
);
5370 cpumask_set_cpu(j
, sched_group_cpus(sg
));
5385 * Initialize sched groups cpu_power.
5387 * cpu_power indicates the capacity of sched group, which is used while
5388 * distributing the load between different sched groups in a sched domain.
5389 * Typically cpu_power for all the groups in a sched domain will be same unless
5390 * there are asymmetries in the topology. If there are asymmetries, group
5391 * having more cpu_power will pickup more load compared to the group having
5394 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
5396 struct sched_group
*sg
= sd
->groups
;
5401 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
5403 } while (sg
!= sd
->groups
);
5405 if (cpu
!= group_balance_cpu(sg
))
5408 update_group_power(sd
, cpu
);
5409 atomic_set(&sg
->sgp
->nr_busy_cpus
, sg
->group_weight
);
5412 int __weak
arch_sd_sibling_asym_packing(void)
5414 return 0*SD_ASYM_PACKING
;
5418 * Initializers for schedule domains
5419 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5422 #ifdef CONFIG_SCHED_DEBUG
5423 # define SD_INIT_NAME(sd, type) sd->name = #type
5425 # define SD_INIT_NAME(sd, type) do { } while (0)
5428 #define SD_INIT_FUNC(type) \
5429 static noinline struct sched_domain * \
5430 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
5432 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
5433 *sd = SD_##type##_INIT; \
5434 SD_INIT_NAME(sd, type); \
5435 sd->private = &tl->data; \
5440 #ifdef CONFIG_SCHED_SMT
5441 SD_INIT_FUNC(SIBLING
)
5443 #ifdef CONFIG_SCHED_MC
5446 #ifdef CONFIG_SCHED_BOOK
5450 static int default_relax_domain_level
= -1;
5451 int sched_domain_level_max
;
5453 static int __init
setup_relax_domain_level(char *str
)
5455 if (kstrtoint(str
, 0, &default_relax_domain_level
))
5456 pr_warn("Unable to set relax_domain_level\n");
5460 __setup("relax_domain_level=", setup_relax_domain_level
);
5462 static void set_domain_attribute(struct sched_domain
*sd
,
5463 struct sched_domain_attr
*attr
)
5467 if (!attr
|| attr
->relax_domain_level
< 0) {
5468 if (default_relax_domain_level
< 0)
5471 request
= default_relax_domain_level
;
5473 request
= attr
->relax_domain_level
;
5474 if (request
< sd
->level
) {
5475 /* turn off idle balance on this domain */
5476 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5478 /* turn on idle balance on this domain */
5479 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5483 static void __sdt_free(const struct cpumask
*cpu_map
);
5484 static int __sdt_alloc(const struct cpumask
*cpu_map
);
5486 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
5487 const struct cpumask
*cpu_map
)
5491 if (!atomic_read(&d
->rd
->refcount
))
5492 free_rootdomain(&d
->rd
->rcu
); /* fall through */
5494 free_percpu(d
->sd
); /* fall through */
5496 __sdt_free(cpu_map
); /* fall through */
5502 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
5503 const struct cpumask
*cpu_map
)
5505 memset(d
, 0, sizeof(*d
));
5507 if (__sdt_alloc(cpu_map
))
5508 return sa_sd_storage
;
5509 d
->sd
= alloc_percpu(struct sched_domain
*);
5511 return sa_sd_storage
;
5512 d
->rd
= alloc_rootdomain();
5515 return sa_rootdomain
;
5519 * NULL the sd_data elements we've used to build the sched_domain and
5520 * sched_group structure so that the subsequent __free_domain_allocs()
5521 * will not free the data we're using.
5523 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
5525 struct sd_data
*sdd
= sd
->private;
5527 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
5528 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
5530 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
5531 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
5533 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
5534 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
5537 #ifdef CONFIG_SCHED_SMT
5538 static const struct cpumask
*cpu_smt_mask(int cpu
)
5540 return topology_thread_cpumask(cpu
);
5545 * Topology list, bottom-up.
5547 static struct sched_domain_topology_level default_topology
[] = {
5548 #ifdef CONFIG_SCHED_SMT
5549 { sd_init_SIBLING
, cpu_smt_mask
, },
5551 #ifdef CONFIG_SCHED_MC
5552 { sd_init_MC
, cpu_coregroup_mask
, },
5554 #ifdef CONFIG_SCHED_BOOK
5555 { sd_init_BOOK
, cpu_book_mask
, },
5557 { sd_init_CPU
, cpu_cpu_mask
, },
5561 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
5563 #define for_each_sd_topology(tl) \
5564 for (tl = sched_domain_topology; tl->init; tl++)
5568 static int sched_domains_numa_levels
;
5569 static int *sched_domains_numa_distance
;
5570 static struct cpumask
***sched_domains_numa_masks
;
5571 static int sched_domains_curr_level
;
5573 static inline int sd_local_flags(int level
)
5575 if (sched_domains_numa_distance
[level
] > RECLAIM_DISTANCE
)
5578 return SD_BALANCE_EXEC
| SD_BALANCE_FORK
| SD_WAKE_AFFINE
;
5581 static struct sched_domain
*
5582 sd_numa_init(struct sched_domain_topology_level
*tl
, int cpu
)
5584 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
5585 int level
= tl
->numa_level
;
5586 int sd_weight
= cpumask_weight(
5587 sched_domains_numa_masks
[level
][cpu_to_node(cpu
)]);
5589 *sd
= (struct sched_domain
){
5590 .min_interval
= sd_weight
,
5591 .max_interval
= 2*sd_weight
,
5593 .imbalance_pct
= 125,
5594 .cache_nice_tries
= 2,
5601 .flags
= 1*SD_LOAD_BALANCE
5602 | 1*SD_BALANCE_NEWIDLE
5607 | 0*SD_SHARE_CPUPOWER
5608 | 0*SD_SHARE_PKG_RESOURCES
5610 | 0*SD_PREFER_SIBLING
5611 | sd_local_flags(level
)
5613 .last_balance
= jiffies
,
5614 .balance_interval
= sd_weight
,
5616 SD_INIT_NAME(sd
, NUMA
);
5617 sd
->private = &tl
->data
;
5620 * Ugly hack to pass state to sd_numa_mask()...
5622 sched_domains_curr_level
= tl
->numa_level
;
5627 static const struct cpumask
*sd_numa_mask(int cpu
)
5629 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
5632 static void sched_numa_warn(const char *str
)
5634 static int done
= false;
5642 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
5644 for (i
= 0; i
< nr_node_ids
; i
++) {
5645 printk(KERN_WARNING
" ");
5646 for (j
= 0; j
< nr_node_ids
; j
++)
5647 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
5648 printk(KERN_CONT
"\n");
5650 printk(KERN_WARNING
"\n");
5653 static bool find_numa_distance(int distance
)
5657 if (distance
== node_distance(0, 0))
5660 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5661 if (sched_domains_numa_distance
[i
] == distance
)
5668 static void sched_init_numa(void)
5670 int next_distance
, curr_distance
= node_distance(0, 0);
5671 struct sched_domain_topology_level
*tl
;
5675 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
5676 if (!sched_domains_numa_distance
)
5680 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
5681 * unique distances in the node_distance() table.
5683 * Assumes node_distance(0,j) includes all distances in
5684 * node_distance(i,j) in order to avoid cubic time.
5686 next_distance
= curr_distance
;
5687 for (i
= 0; i
< nr_node_ids
; i
++) {
5688 for (j
= 0; j
< nr_node_ids
; j
++) {
5689 for (k
= 0; k
< nr_node_ids
; k
++) {
5690 int distance
= node_distance(i
, k
);
5692 if (distance
> curr_distance
&&
5693 (distance
< next_distance
||
5694 next_distance
== curr_distance
))
5695 next_distance
= distance
;
5698 * While not a strong assumption it would be nice to know
5699 * about cases where if node A is connected to B, B is not
5700 * equally connected to A.
5702 if (sched_debug() && node_distance(k
, i
) != distance
)
5703 sched_numa_warn("Node-distance not symmetric");
5705 if (sched_debug() && i
&& !find_numa_distance(distance
))
5706 sched_numa_warn("Node-0 not representative");
5708 if (next_distance
!= curr_distance
) {
5709 sched_domains_numa_distance
[level
++] = next_distance
;
5710 sched_domains_numa_levels
= level
;
5711 curr_distance
= next_distance
;
5716 * In case of sched_debug() we verify the above assumption.
5722 * 'level' contains the number of unique distances, excluding the
5723 * identity distance node_distance(i,i).
5725 * The sched_domains_numa_distance[] array includes the actual distance
5730 * Here, we should temporarily reset sched_domains_numa_levels to 0.
5731 * If it fails to allocate memory for array sched_domains_numa_masks[][],
5732 * the array will contain less then 'level' members. This could be
5733 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
5734 * in other functions.
5736 * We reset it to 'level' at the end of this function.
5738 sched_domains_numa_levels
= 0;
5740 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
5741 if (!sched_domains_numa_masks
)
5745 * Now for each level, construct a mask per node which contains all
5746 * cpus of nodes that are that many hops away from us.
5748 for (i
= 0; i
< level
; i
++) {
5749 sched_domains_numa_masks
[i
] =
5750 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
5751 if (!sched_domains_numa_masks
[i
])
5754 for (j
= 0; j
< nr_node_ids
; j
++) {
5755 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
5759 sched_domains_numa_masks
[i
][j
] = mask
;
5761 for (k
= 0; k
< nr_node_ids
; k
++) {
5762 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
5765 cpumask_or(mask
, mask
, cpumask_of_node(k
));
5770 tl
= kzalloc((ARRAY_SIZE(default_topology
) + level
) *
5771 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
5776 * Copy the default topology bits..
5778 for (i
= 0; default_topology
[i
].init
; i
++)
5779 tl
[i
] = default_topology
[i
];
5782 * .. and append 'j' levels of NUMA goodness.
5784 for (j
= 0; j
< level
; i
++, j
++) {
5785 tl
[i
] = (struct sched_domain_topology_level
){
5786 .init
= sd_numa_init
,
5787 .mask
= sd_numa_mask
,
5788 .flags
= SDTL_OVERLAP
,
5793 sched_domain_topology
= tl
;
5795 sched_domains_numa_levels
= level
;
5798 static void sched_domains_numa_masks_set(int cpu
)
5801 int node
= cpu_to_node(cpu
);
5803 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5804 for (j
= 0; j
< nr_node_ids
; j
++) {
5805 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
5806 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
5811 static void sched_domains_numa_masks_clear(int cpu
)
5814 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
5815 for (j
= 0; j
< nr_node_ids
; j
++)
5816 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
5821 * Update sched_domains_numa_masks[level][node] array when new cpus
5824 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
5825 unsigned long action
,
5828 int cpu
= (long)hcpu
;
5830 switch (action
& ~CPU_TASKS_FROZEN
) {
5832 sched_domains_numa_masks_set(cpu
);
5836 sched_domains_numa_masks_clear(cpu
);
5846 static inline void sched_init_numa(void)
5850 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
5851 unsigned long action
,
5856 #endif /* CONFIG_NUMA */
5858 static int __sdt_alloc(const struct cpumask
*cpu_map
)
5860 struct sched_domain_topology_level
*tl
;
5863 for_each_sd_topology(tl
) {
5864 struct sd_data
*sdd
= &tl
->data
;
5866 sdd
->sd
= alloc_percpu(struct sched_domain
*);
5870 sdd
->sg
= alloc_percpu(struct sched_group
*);
5874 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
5878 for_each_cpu(j
, cpu_map
) {
5879 struct sched_domain
*sd
;
5880 struct sched_group
*sg
;
5881 struct sched_group_power
*sgp
;
5883 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
5884 GFP_KERNEL
, cpu_to_node(j
));
5888 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
5890 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5891 GFP_KERNEL
, cpu_to_node(j
));
5897 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
5899 sgp
= kzalloc_node(sizeof(struct sched_group_power
) + cpumask_size(),
5900 GFP_KERNEL
, cpu_to_node(j
));
5904 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
5911 static void __sdt_free(const struct cpumask
*cpu_map
)
5913 struct sched_domain_topology_level
*tl
;
5916 for_each_sd_topology(tl
) {
5917 struct sd_data
*sdd
= &tl
->data
;
5919 for_each_cpu(j
, cpu_map
) {
5920 struct sched_domain
*sd
;
5923 sd
= *per_cpu_ptr(sdd
->sd
, j
);
5924 if (sd
&& (sd
->flags
& SD_OVERLAP
))
5925 free_sched_groups(sd
->groups
, 0);
5926 kfree(*per_cpu_ptr(sdd
->sd
, j
));
5930 kfree(*per_cpu_ptr(sdd
->sg
, j
));
5932 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
5934 free_percpu(sdd
->sd
);
5936 free_percpu(sdd
->sg
);
5938 free_percpu(sdd
->sgp
);
5943 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
5944 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
5945 struct sched_domain
*child
, int cpu
)
5947 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
5951 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
5953 sd
->level
= child
->level
+ 1;
5954 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
5958 set_domain_attribute(sd
, attr
);
5964 * Build sched domains for a given set of cpus and attach the sched domains
5965 * to the individual cpus
5967 static int build_sched_domains(const struct cpumask
*cpu_map
,
5968 struct sched_domain_attr
*attr
)
5970 enum s_alloc alloc_state
;
5971 struct sched_domain
*sd
;
5973 int i
, ret
= -ENOMEM
;
5975 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
5976 if (alloc_state
!= sa_rootdomain
)
5979 /* Set up domains for cpus specified by the cpu_map. */
5980 for_each_cpu(i
, cpu_map
) {
5981 struct sched_domain_topology_level
*tl
;
5984 for_each_sd_topology(tl
) {
5985 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
5986 if (tl
== sched_domain_topology
)
5987 *per_cpu_ptr(d
.sd
, i
) = sd
;
5988 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
5989 sd
->flags
|= SD_OVERLAP
;
5990 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
5995 /* Build the groups for the domains */
5996 for_each_cpu(i
, cpu_map
) {
5997 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
5998 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
5999 if (sd
->flags
& SD_OVERLAP
) {
6000 if (build_overlap_sched_groups(sd
, i
))
6003 if (build_sched_groups(sd
, i
))
6009 /* Calculate CPU power for physical packages and nodes */
6010 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6011 if (!cpumask_test_cpu(i
, cpu_map
))
6014 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6015 claim_allocations(i
, sd
);
6016 init_sched_groups_power(i
, sd
);
6020 /* Attach the domains */
6022 for_each_cpu(i
, cpu_map
) {
6023 sd
= *per_cpu_ptr(d
.sd
, i
);
6024 cpu_attach_domain(sd
, d
.rd
, i
);
6030 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6034 static cpumask_var_t
*doms_cur
; /* current sched domains */
6035 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6036 static struct sched_domain_attr
*dattr_cur
;
6037 /* attribues of custom domains in 'doms_cur' */
6040 * Special case: If a kmalloc of a doms_cur partition (array of
6041 * cpumask) fails, then fallback to a single sched domain,
6042 * as determined by the single cpumask fallback_doms.
6044 static cpumask_var_t fallback_doms
;
6047 * arch_update_cpu_topology lets virtualized architectures update the
6048 * cpu core maps. It is supposed to return 1 if the topology changed
6049 * or 0 if it stayed the same.
6051 int __attribute__((weak
)) arch_update_cpu_topology(void)
6056 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6059 cpumask_var_t
*doms
;
6061 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6064 for (i
= 0; i
< ndoms
; i
++) {
6065 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6066 free_sched_domains(doms
, i
);
6073 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6076 for (i
= 0; i
< ndoms
; i
++)
6077 free_cpumask_var(doms
[i
]);
6082 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6083 * For now this just excludes isolated cpus, but could be used to
6084 * exclude other special cases in the future.
6086 static int init_sched_domains(const struct cpumask
*cpu_map
)
6090 arch_update_cpu_topology();
6092 doms_cur
= alloc_sched_domains(ndoms_cur
);
6094 doms_cur
= &fallback_doms
;
6095 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6096 err
= build_sched_domains(doms_cur
[0], NULL
);
6097 register_sched_domain_sysctl();
6103 * Detach sched domains from a group of cpus specified in cpu_map
6104 * These cpus will now be attached to the NULL domain
6106 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6111 for_each_cpu(i
, cpu_map
)
6112 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6116 /* handle null as "default" */
6117 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6118 struct sched_domain_attr
*new, int idx_new
)
6120 struct sched_domain_attr tmp
;
6127 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6128 new ? (new + idx_new
) : &tmp
,
6129 sizeof(struct sched_domain_attr
));
6133 * Partition sched domains as specified by the 'ndoms_new'
6134 * cpumasks in the array doms_new[] of cpumasks. This compares
6135 * doms_new[] to the current sched domain partitioning, doms_cur[].
6136 * It destroys each deleted domain and builds each new domain.
6138 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6139 * The masks don't intersect (don't overlap.) We should setup one
6140 * sched domain for each mask. CPUs not in any of the cpumasks will
6141 * not be load balanced. If the same cpumask appears both in the
6142 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6145 * The passed in 'doms_new' should be allocated using
6146 * alloc_sched_domains. This routine takes ownership of it and will
6147 * free_sched_domains it when done with it. If the caller failed the
6148 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6149 * and partition_sched_domains() will fallback to the single partition
6150 * 'fallback_doms', it also forces the domains to be rebuilt.
6152 * If doms_new == NULL it will be replaced with cpu_online_mask.
6153 * ndoms_new == 0 is a special case for destroying existing domains,
6154 * and it will not create the default domain.
6156 * Call with hotplug lock held
6158 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6159 struct sched_domain_attr
*dattr_new
)
6164 mutex_lock(&sched_domains_mutex
);
6166 /* always unregister in case we don't destroy any domains */
6167 unregister_sched_domain_sysctl();
6169 /* Let architecture update cpu core mappings. */
6170 new_topology
= arch_update_cpu_topology();
6172 n
= doms_new
? ndoms_new
: 0;
6174 /* Destroy deleted domains */
6175 for (i
= 0; i
< ndoms_cur
; i
++) {
6176 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6177 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6178 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6181 /* no match - a current sched domain not in new doms_new[] */
6182 detach_destroy_domains(doms_cur
[i
]);
6187 if (doms_new
== NULL
) {
6189 doms_new
= &fallback_doms
;
6190 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6191 WARN_ON_ONCE(dattr_new
);
6194 /* Build new domains */
6195 for (i
= 0; i
< ndoms_new
; i
++) {
6196 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
6197 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6198 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6201 /* no match - add a new doms_new */
6202 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6207 /* Remember the new sched domains */
6208 if (doms_cur
!= &fallback_doms
)
6209 free_sched_domains(doms_cur
, ndoms_cur
);
6210 kfree(dattr_cur
); /* kfree(NULL) is safe */
6211 doms_cur
= doms_new
;
6212 dattr_cur
= dattr_new
;
6213 ndoms_cur
= ndoms_new
;
6215 register_sched_domain_sysctl();
6217 mutex_unlock(&sched_domains_mutex
);
6220 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6223 * Update cpusets according to cpu_active mask. If cpusets are
6224 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6225 * around partition_sched_domains().
6227 * If we come here as part of a suspend/resume, don't touch cpusets because we
6228 * want to restore it back to its original state upon resume anyway.
6230 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6234 case CPU_ONLINE_FROZEN
:
6235 case CPU_DOWN_FAILED_FROZEN
:
6238 * num_cpus_frozen tracks how many CPUs are involved in suspend
6239 * resume sequence. As long as this is not the last online
6240 * operation in the resume sequence, just build a single sched
6241 * domain, ignoring cpusets.
6244 if (likely(num_cpus_frozen
)) {
6245 partition_sched_domains(1, NULL
, NULL
);
6250 * This is the last CPU online operation. So fall through and
6251 * restore the original sched domains by considering the
6252 * cpuset configurations.
6256 case CPU_DOWN_FAILED
:
6257 cpuset_update_active_cpus(true);
6265 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6269 case CPU_DOWN_PREPARE
:
6270 cpuset_update_active_cpus(false);
6272 case CPU_DOWN_PREPARE_FROZEN
:
6274 partition_sched_domains(1, NULL
, NULL
);
6282 void __init
sched_init_smp(void)
6284 cpumask_var_t non_isolated_cpus
;
6286 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6287 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6292 mutex_lock(&sched_domains_mutex
);
6293 init_sched_domains(cpu_active_mask
);
6294 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6295 if (cpumask_empty(non_isolated_cpus
))
6296 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6297 mutex_unlock(&sched_domains_mutex
);
6300 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
6301 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6302 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6306 /* Move init over to a non-isolated CPU */
6307 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6309 sched_init_granularity();
6310 free_cpumask_var(non_isolated_cpus
);
6312 init_sched_rt_class();
6315 void __init
sched_init_smp(void)
6317 sched_init_granularity();
6319 #endif /* CONFIG_SMP */
6321 const_debug
unsigned int sysctl_timer_migration
= 1;
6323 int in_sched_functions(unsigned long addr
)
6325 return in_lock_functions(addr
) ||
6326 (addr
>= (unsigned long)__sched_text_start
6327 && addr
< (unsigned long)__sched_text_end
);
6330 #ifdef CONFIG_CGROUP_SCHED
6332 * Default task group.
6333 * Every task in system belongs to this group at bootup.
6335 struct task_group root_task_group
;
6336 LIST_HEAD(task_groups
);
6339 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
6341 void __init
sched_init(void)
6344 unsigned long alloc_size
= 0, ptr
;
6346 #ifdef CONFIG_FAIR_GROUP_SCHED
6347 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6349 #ifdef CONFIG_RT_GROUP_SCHED
6350 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6352 #ifdef CONFIG_CPUMASK_OFFSTACK
6353 alloc_size
+= num_possible_cpus() * cpumask_size();
6356 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6358 #ifdef CONFIG_FAIR_GROUP_SCHED
6359 root_task_group
.se
= (struct sched_entity
**)ptr
;
6360 ptr
+= nr_cpu_ids
* sizeof(void **);
6362 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6363 ptr
+= nr_cpu_ids
* sizeof(void **);
6365 #endif /* CONFIG_FAIR_GROUP_SCHED */
6366 #ifdef CONFIG_RT_GROUP_SCHED
6367 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6368 ptr
+= nr_cpu_ids
* sizeof(void **);
6370 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6371 ptr
+= nr_cpu_ids
* sizeof(void **);
6373 #endif /* CONFIG_RT_GROUP_SCHED */
6374 #ifdef CONFIG_CPUMASK_OFFSTACK
6375 for_each_possible_cpu(i
) {
6376 per_cpu(load_balance_mask
, i
) = (void *)ptr
;
6377 ptr
+= cpumask_size();
6379 #endif /* CONFIG_CPUMASK_OFFSTACK */
6383 init_defrootdomain();
6386 init_rt_bandwidth(&def_rt_bandwidth
,
6387 global_rt_period(), global_rt_runtime());
6389 #ifdef CONFIG_RT_GROUP_SCHED
6390 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6391 global_rt_period(), global_rt_runtime());
6392 #endif /* CONFIG_RT_GROUP_SCHED */
6394 #ifdef CONFIG_CGROUP_SCHED
6395 list_add(&root_task_group
.list
, &task_groups
);
6396 INIT_LIST_HEAD(&root_task_group
.children
);
6397 INIT_LIST_HEAD(&root_task_group
.siblings
);
6398 autogroup_init(&init_task
);
6400 #endif /* CONFIG_CGROUP_SCHED */
6402 for_each_possible_cpu(i
) {
6406 raw_spin_lock_init(&rq
->lock
);
6408 rq
->calc_load_active
= 0;
6409 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6410 init_cfs_rq(&rq
->cfs
);
6411 init_rt_rq(&rq
->rt
, rq
);
6412 #ifdef CONFIG_FAIR_GROUP_SCHED
6413 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6414 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6416 * How much cpu bandwidth does root_task_group get?
6418 * In case of task-groups formed thr' the cgroup filesystem, it
6419 * gets 100% of the cpu resources in the system. This overall
6420 * system cpu resource is divided among the tasks of
6421 * root_task_group and its child task-groups in a fair manner,
6422 * based on each entity's (task or task-group's) weight
6423 * (se->load.weight).
6425 * In other words, if root_task_group has 10 tasks of weight
6426 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6427 * then A0's share of the cpu resource is:
6429 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6431 * We achieve this by letting root_task_group's tasks sit
6432 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6434 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6435 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6436 #endif /* CONFIG_FAIR_GROUP_SCHED */
6438 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6439 #ifdef CONFIG_RT_GROUP_SCHED
6440 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
6441 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6444 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6445 rq
->cpu_load
[j
] = 0;
6447 rq
->last_load_update_tick
= jiffies
;
6452 rq
->cpu_power
= SCHED_POWER_SCALE
;
6453 rq
->post_schedule
= 0;
6454 rq
->active_balance
= 0;
6455 rq
->next_balance
= jiffies
;
6460 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
6462 INIT_LIST_HEAD(&rq
->cfs_tasks
);
6464 rq_attach_root(rq
, &def_root_domain
);
6465 #ifdef CONFIG_NO_HZ_COMMON
6468 #ifdef CONFIG_NO_HZ_FULL
6469 rq
->last_sched_tick
= 0;
6473 atomic_set(&rq
->nr_iowait
, 0);
6476 set_load_weight(&init_task
);
6478 #ifdef CONFIG_PREEMPT_NOTIFIERS
6479 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
6482 #ifdef CONFIG_RT_MUTEXES
6483 plist_head_init(&init_task
.pi_waiters
);
6487 * The boot idle thread does lazy MMU switching as well:
6489 atomic_inc(&init_mm
.mm_count
);
6490 enter_lazy_tlb(&init_mm
, current
);
6493 * Make us the idle thread. Technically, schedule() should not be
6494 * called from this thread, however somewhere below it might be,
6495 * but because we are the idle thread, we just pick up running again
6496 * when this runqueue becomes "idle".
6498 init_idle(current
, smp_processor_id());
6500 calc_load_update
= jiffies
+ LOAD_FREQ
;
6503 * During early bootup we pretend to be a normal task:
6505 current
->sched_class
= &fair_sched_class
;
6508 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
6509 /* May be allocated at isolcpus cmdline parse time */
6510 if (cpu_isolated_map
== NULL
)
6511 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
6512 idle_thread_set_boot_cpu();
6514 init_sched_fair_class();
6516 scheduler_running
= 1;
6519 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6520 static inline int preempt_count_equals(int preempt_offset
)
6522 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
6524 return (nested
== preempt_offset
);
6527 void __might_sleep(const char *file
, int line
, int preempt_offset
)
6529 static unsigned long prev_jiffy
; /* ratelimiting */
6531 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
6532 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
6533 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
6535 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
6537 prev_jiffy
= jiffies
;
6540 "BUG: sleeping function called from invalid context at %s:%d\n",
6543 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
6544 in_atomic(), irqs_disabled(),
6545 current
->pid
, current
->comm
);
6547 debug_show_held_locks(current
);
6548 if (irqs_disabled())
6549 print_irqtrace_events(current
);
6552 EXPORT_SYMBOL(__might_sleep
);
6555 #ifdef CONFIG_MAGIC_SYSRQ
6556 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
6558 const struct sched_class
*prev_class
= p
->sched_class
;
6559 int old_prio
= p
->prio
;
6564 dequeue_task(rq
, p
, 0);
6565 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
6567 enqueue_task(rq
, p
, 0);
6568 resched_task(rq
->curr
);
6571 check_class_changed(rq
, p
, prev_class
, old_prio
);
6574 void normalize_rt_tasks(void)
6576 struct task_struct
*g
, *p
;
6577 unsigned long flags
;
6580 read_lock_irqsave(&tasklist_lock
, flags
);
6581 do_each_thread(g
, p
) {
6583 * Only normalize user tasks:
6588 p
->se
.exec_start
= 0;
6589 #ifdef CONFIG_SCHEDSTATS
6590 p
->se
.statistics
.wait_start
= 0;
6591 p
->se
.statistics
.sleep_start
= 0;
6592 p
->se
.statistics
.block_start
= 0;
6597 * Renice negative nice level userspace
6600 if (TASK_NICE(p
) < 0 && p
->mm
)
6601 set_user_nice(p
, 0);
6605 raw_spin_lock(&p
->pi_lock
);
6606 rq
= __task_rq_lock(p
);
6608 normalize_task(rq
, p
);
6610 __task_rq_unlock(rq
);
6611 raw_spin_unlock(&p
->pi_lock
);
6612 } while_each_thread(g
, p
);
6614 read_unlock_irqrestore(&tasklist_lock
, flags
);
6617 #endif /* CONFIG_MAGIC_SYSRQ */
6619 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
6621 * These functions are only useful for the IA64 MCA handling, or kdb.
6623 * They can only be called when the whole system has been
6624 * stopped - every CPU needs to be quiescent, and no scheduling
6625 * activity can take place. Using them for anything else would
6626 * be a serious bug, and as a result, they aren't even visible
6627 * under any other configuration.
6631 * curr_task - return the current task for a given cpu.
6632 * @cpu: the processor in question.
6634 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6636 struct task_struct
*curr_task(int cpu
)
6638 return cpu_curr(cpu
);
6641 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
6645 * set_curr_task - set the current task for a given cpu.
6646 * @cpu: the processor in question.
6647 * @p: the task pointer to set.
6649 * Description: This function must only be used when non-maskable interrupts
6650 * are serviced on a separate stack. It allows the architecture to switch the
6651 * notion of the current task on a cpu in a non-blocking manner. This function
6652 * must be called with all CPU's synchronized, and interrupts disabled, the
6653 * and caller must save the original value of the current task (see
6654 * curr_task() above) and restore that value before reenabling interrupts and
6655 * re-starting the system.
6657 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6659 void set_curr_task(int cpu
, struct task_struct
*p
)
6666 #ifdef CONFIG_CGROUP_SCHED
6667 /* task_group_lock serializes the addition/removal of task groups */
6668 static DEFINE_SPINLOCK(task_group_lock
);
6670 static void free_sched_group(struct task_group
*tg
)
6672 free_fair_sched_group(tg
);
6673 free_rt_sched_group(tg
);
6678 /* allocate runqueue etc for a new task group */
6679 struct task_group
*sched_create_group(struct task_group
*parent
)
6681 struct task_group
*tg
;
6683 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
6685 return ERR_PTR(-ENOMEM
);
6687 if (!alloc_fair_sched_group(tg
, parent
))
6690 if (!alloc_rt_sched_group(tg
, parent
))
6696 free_sched_group(tg
);
6697 return ERR_PTR(-ENOMEM
);
6700 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
6702 unsigned long flags
;
6704 spin_lock_irqsave(&task_group_lock
, flags
);
6705 list_add_rcu(&tg
->list
, &task_groups
);
6707 WARN_ON(!parent
); /* root should already exist */
6709 tg
->parent
= parent
;
6710 INIT_LIST_HEAD(&tg
->children
);
6711 list_add_rcu(&tg
->siblings
, &parent
->children
);
6712 spin_unlock_irqrestore(&task_group_lock
, flags
);
6715 /* rcu callback to free various structures associated with a task group */
6716 static void free_sched_group_rcu(struct rcu_head
*rhp
)
6718 /* now it should be safe to free those cfs_rqs */
6719 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
6722 /* Destroy runqueue etc associated with a task group */
6723 void sched_destroy_group(struct task_group
*tg
)
6725 /* wait for possible concurrent references to cfs_rqs complete */
6726 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
6729 void sched_offline_group(struct task_group
*tg
)
6731 unsigned long flags
;
6734 /* end participation in shares distribution */
6735 for_each_possible_cpu(i
)
6736 unregister_fair_sched_group(tg
, i
);
6738 spin_lock_irqsave(&task_group_lock
, flags
);
6739 list_del_rcu(&tg
->list
);
6740 list_del_rcu(&tg
->siblings
);
6741 spin_unlock_irqrestore(&task_group_lock
, flags
);
6744 /* change task's runqueue when it moves between groups.
6745 * The caller of this function should have put the task in its new group
6746 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
6747 * reflect its new group.
6749 void sched_move_task(struct task_struct
*tsk
)
6751 struct task_group
*tg
;
6753 unsigned long flags
;
6756 rq
= task_rq_lock(tsk
, &flags
);
6758 running
= task_current(rq
, tsk
);
6762 dequeue_task(rq
, tsk
, 0);
6763 if (unlikely(running
))
6764 tsk
->sched_class
->put_prev_task(rq
, tsk
);
6766 tg
= container_of(task_subsys_state_check(tsk
, cpu_cgroup_subsys_id
,
6767 lockdep_is_held(&tsk
->sighand
->siglock
)),
6768 struct task_group
, css
);
6769 tg
= autogroup_task_group(tsk
, tg
);
6770 tsk
->sched_task_group
= tg
;
6772 #ifdef CONFIG_FAIR_GROUP_SCHED
6773 if (tsk
->sched_class
->task_move_group
)
6774 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
6777 set_task_rq(tsk
, task_cpu(tsk
));
6779 if (unlikely(running
))
6780 tsk
->sched_class
->set_curr_task(rq
);
6782 enqueue_task(rq
, tsk
, 0);
6784 task_rq_unlock(rq
, tsk
, &flags
);
6786 #endif /* CONFIG_CGROUP_SCHED */
6788 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
6789 static unsigned long to_ratio(u64 period
, u64 runtime
)
6791 if (runtime
== RUNTIME_INF
)
6794 return div64_u64(runtime
<< 20, period
);
6798 #ifdef CONFIG_RT_GROUP_SCHED
6800 * Ensure that the real time constraints are schedulable.
6802 static DEFINE_MUTEX(rt_constraints_mutex
);
6804 /* Must be called with tasklist_lock held */
6805 static inline int tg_has_rt_tasks(struct task_group
*tg
)
6807 struct task_struct
*g
, *p
;
6809 do_each_thread(g
, p
) {
6810 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
6812 } while_each_thread(g
, p
);
6817 struct rt_schedulable_data
{
6818 struct task_group
*tg
;
6823 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
6825 struct rt_schedulable_data
*d
= data
;
6826 struct task_group
*child
;
6827 unsigned long total
, sum
= 0;
6828 u64 period
, runtime
;
6830 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
6831 runtime
= tg
->rt_bandwidth
.rt_runtime
;
6834 period
= d
->rt_period
;
6835 runtime
= d
->rt_runtime
;
6839 * Cannot have more runtime than the period.
6841 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
6845 * Ensure we don't starve existing RT tasks.
6847 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
6850 total
= to_ratio(period
, runtime
);
6853 * Nobody can have more than the global setting allows.
6855 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
6859 * The sum of our children's runtime should not exceed our own.
6861 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
6862 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
6863 runtime
= child
->rt_bandwidth
.rt_runtime
;
6865 if (child
== d
->tg
) {
6866 period
= d
->rt_period
;
6867 runtime
= d
->rt_runtime
;
6870 sum
+= to_ratio(period
, runtime
);
6879 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
6883 struct rt_schedulable_data data
= {
6885 .rt_period
= period
,
6886 .rt_runtime
= runtime
,
6890 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
6896 static int tg_set_rt_bandwidth(struct task_group
*tg
,
6897 u64 rt_period
, u64 rt_runtime
)
6901 mutex_lock(&rt_constraints_mutex
);
6902 read_lock(&tasklist_lock
);
6903 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
6907 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
6908 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
6909 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
6911 for_each_possible_cpu(i
) {
6912 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
6914 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
6915 rt_rq
->rt_runtime
= rt_runtime
;
6916 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
6918 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
6920 read_unlock(&tasklist_lock
);
6921 mutex_unlock(&rt_constraints_mutex
);
6926 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
6928 u64 rt_runtime
, rt_period
;
6930 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
6931 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
6932 if (rt_runtime_us
< 0)
6933 rt_runtime
= RUNTIME_INF
;
6935 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
6938 static long sched_group_rt_runtime(struct task_group
*tg
)
6942 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
6945 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
6946 do_div(rt_runtime_us
, NSEC_PER_USEC
);
6947 return rt_runtime_us
;
6950 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
6952 u64 rt_runtime
, rt_period
;
6954 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
6955 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
6960 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
6963 static long sched_group_rt_period(struct task_group
*tg
)
6967 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
6968 do_div(rt_period_us
, NSEC_PER_USEC
);
6969 return rt_period_us
;
6972 static int sched_rt_global_constraints(void)
6974 u64 runtime
, period
;
6977 if (sysctl_sched_rt_period
<= 0)
6980 runtime
= global_rt_runtime();
6981 period
= global_rt_period();
6984 * Sanity check on the sysctl variables.
6986 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
6989 mutex_lock(&rt_constraints_mutex
);
6990 read_lock(&tasklist_lock
);
6991 ret
= __rt_schedulable(NULL
, 0, 0);
6992 read_unlock(&tasklist_lock
);
6993 mutex_unlock(&rt_constraints_mutex
);
6998 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7000 /* Don't accept realtime tasks when there is no way for them to run */
7001 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7007 #else /* !CONFIG_RT_GROUP_SCHED */
7008 static int sched_rt_global_constraints(void)
7010 unsigned long flags
;
7013 if (sysctl_sched_rt_period
<= 0)
7017 * There's always some RT tasks in the root group
7018 * -- migration, kstopmachine etc..
7020 if (sysctl_sched_rt_runtime
== 0)
7023 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7024 for_each_possible_cpu(i
) {
7025 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7027 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7028 rt_rq
->rt_runtime
= global_rt_runtime();
7029 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7031 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7035 #endif /* CONFIG_RT_GROUP_SCHED */
7037 int sched_rr_handler(struct ctl_table
*table
, int write
,
7038 void __user
*buffer
, size_t *lenp
,
7042 static DEFINE_MUTEX(mutex
);
7045 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7046 /* make sure that internally we keep jiffies */
7047 /* also, writing zero resets timeslice to default */
7048 if (!ret
&& write
) {
7049 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7050 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7052 mutex_unlock(&mutex
);
7056 int sched_rt_handler(struct ctl_table
*table
, int write
,
7057 void __user
*buffer
, size_t *lenp
,
7061 int old_period
, old_runtime
;
7062 static DEFINE_MUTEX(mutex
);
7065 old_period
= sysctl_sched_rt_period
;
7066 old_runtime
= sysctl_sched_rt_runtime
;
7068 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7070 if (!ret
&& write
) {
7071 ret
= sched_rt_global_constraints();
7073 sysctl_sched_rt_period
= old_period
;
7074 sysctl_sched_rt_runtime
= old_runtime
;
7076 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7077 def_rt_bandwidth
.rt_period
=
7078 ns_to_ktime(global_rt_period());
7081 mutex_unlock(&mutex
);
7086 #ifdef CONFIG_CGROUP_SCHED
7088 /* return corresponding task_group object of a cgroup */
7089 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
7091 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
7092 struct task_group
, css
);
7095 static struct cgroup_subsys_state
*cpu_cgroup_css_alloc(struct cgroup
*cgrp
)
7097 struct task_group
*tg
, *parent
;
7099 if (!cgrp
->parent
) {
7100 /* This is early initialization for the top cgroup */
7101 return &root_task_group
.css
;
7104 parent
= cgroup_tg(cgrp
->parent
);
7105 tg
= sched_create_group(parent
);
7107 return ERR_PTR(-ENOMEM
);
7112 static int cpu_cgroup_css_online(struct cgroup
*cgrp
)
7114 struct task_group
*tg
= cgroup_tg(cgrp
);
7115 struct task_group
*parent
;
7120 parent
= cgroup_tg(cgrp
->parent
);
7121 sched_online_group(tg
, parent
);
7125 static void cpu_cgroup_css_free(struct cgroup
*cgrp
)
7127 struct task_group
*tg
= cgroup_tg(cgrp
);
7129 sched_destroy_group(tg
);
7132 static void cpu_cgroup_css_offline(struct cgroup
*cgrp
)
7134 struct task_group
*tg
= cgroup_tg(cgrp
);
7136 sched_offline_group(tg
);
7139 static int cpu_cgroup_can_attach(struct cgroup
*cgrp
,
7140 struct cgroup_taskset
*tset
)
7142 struct task_struct
*task
;
7144 cgroup_taskset_for_each(task
, cgrp
, tset
) {
7145 #ifdef CONFIG_RT_GROUP_SCHED
7146 if (!sched_rt_can_attach(cgroup_tg(cgrp
), task
))
7149 /* We don't support RT-tasks being in separate groups */
7150 if (task
->sched_class
!= &fair_sched_class
)
7157 static void cpu_cgroup_attach(struct cgroup
*cgrp
,
7158 struct cgroup_taskset
*tset
)
7160 struct task_struct
*task
;
7162 cgroup_taskset_for_each(task
, cgrp
, tset
)
7163 sched_move_task(task
);
7167 cpu_cgroup_exit(struct cgroup
*cgrp
, struct cgroup
*old_cgrp
,
7168 struct task_struct
*task
)
7171 * cgroup_exit() is called in the copy_process() failure path.
7172 * Ignore this case since the task hasn't ran yet, this avoids
7173 * trying to poke a half freed task state from generic code.
7175 if (!(task
->flags
& PF_EXITING
))
7178 sched_move_task(task
);
7181 #ifdef CONFIG_FAIR_GROUP_SCHED
7182 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7185 return sched_group_set_shares(cgroup_tg(cgrp
), scale_load(shareval
));
7188 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7190 struct task_group
*tg
= cgroup_tg(cgrp
);
7192 return (u64
) scale_load_down(tg
->shares
);
7195 #ifdef CONFIG_CFS_BANDWIDTH
7196 static DEFINE_MUTEX(cfs_constraints_mutex
);
7198 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7199 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7201 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7203 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7205 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7206 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7208 if (tg
== &root_task_group
)
7212 * Ensure we have at some amount of bandwidth every period. This is
7213 * to prevent reaching a state of large arrears when throttled via
7214 * entity_tick() resulting in prolonged exit starvation.
7216 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7220 * Likewise, bound things on the otherside by preventing insane quota
7221 * periods. This also allows us to normalize in computing quota
7224 if (period
> max_cfs_quota_period
)
7227 mutex_lock(&cfs_constraints_mutex
);
7228 ret
= __cfs_schedulable(tg
, period
, quota
);
7232 runtime_enabled
= quota
!= RUNTIME_INF
;
7233 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7234 account_cfs_bandwidth_used(runtime_enabled
, runtime_was_enabled
);
7235 raw_spin_lock_irq(&cfs_b
->lock
);
7236 cfs_b
->period
= ns_to_ktime(period
);
7237 cfs_b
->quota
= quota
;
7239 __refill_cfs_bandwidth_runtime(cfs_b
);
7240 /* restart the period timer (if active) to handle new period expiry */
7241 if (runtime_enabled
&& cfs_b
->timer_active
) {
7242 /* force a reprogram */
7243 cfs_b
->timer_active
= 0;
7244 __start_cfs_bandwidth(cfs_b
);
7246 raw_spin_unlock_irq(&cfs_b
->lock
);
7248 for_each_possible_cpu(i
) {
7249 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7250 struct rq
*rq
= cfs_rq
->rq
;
7252 raw_spin_lock_irq(&rq
->lock
);
7253 cfs_rq
->runtime_enabled
= runtime_enabled
;
7254 cfs_rq
->runtime_remaining
= 0;
7256 if (cfs_rq
->throttled
)
7257 unthrottle_cfs_rq(cfs_rq
);
7258 raw_spin_unlock_irq(&rq
->lock
);
7261 mutex_unlock(&cfs_constraints_mutex
);
7266 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7270 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7271 if (cfs_quota_us
< 0)
7272 quota
= RUNTIME_INF
;
7274 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7276 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7279 long tg_get_cfs_quota(struct task_group
*tg
)
7283 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7286 quota_us
= tg
->cfs_bandwidth
.quota
;
7287 do_div(quota_us
, NSEC_PER_USEC
);
7292 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7296 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7297 quota
= tg
->cfs_bandwidth
.quota
;
7299 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7302 long tg_get_cfs_period(struct task_group
*tg
)
7306 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7307 do_div(cfs_period_us
, NSEC_PER_USEC
);
7309 return cfs_period_us
;
7312 static s64
cpu_cfs_quota_read_s64(struct cgroup
*cgrp
, struct cftype
*cft
)
7314 return tg_get_cfs_quota(cgroup_tg(cgrp
));
7317 static int cpu_cfs_quota_write_s64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7320 return tg_set_cfs_quota(cgroup_tg(cgrp
), cfs_quota_us
);
7323 static u64
cpu_cfs_period_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7325 return tg_get_cfs_period(cgroup_tg(cgrp
));
7328 static int cpu_cfs_period_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7331 return tg_set_cfs_period(cgroup_tg(cgrp
), cfs_period_us
);
7334 struct cfs_schedulable_data
{
7335 struct task_group
*tg
;
7340 * normalize group quota/period to be quota/max_period
7341 * note: units are usecs
7343 static u64
normalize_cfs_quota(struct task_group
*tg
,
7344 struct cfs_schedulable_data
*d
)
7352 period
= tg_get_cfs_period(tg
);
7353 quota
= tg_get_cfs_quota(tg
);
7356 /* note: these should typically be equivalent */
7357 if (quota
== RUNTIME_INF
|| quota
== -1)
7360 return to_ratio(period
, quota
);
7363 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7365 struct cfs_schedulable_data
*d
= data
;
7366 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7367 s64 quota
= 0, parent_quota
= -1;
7370 quota
= RUNTIME_INF
;
7372 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
7374 quota
= normalize_cfs_quota(tg
, d
);
7375 parent_quota
= parent_b
->hierarchal_quota
;
7378 * ensure max(child_quota) <= parent_quota, inherit when no
7381 if (quota
== RUNTIME_INF
)
7382 quota
= parent_quota
;
7383 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
7386 cfs_b
->hierarchal_quota
= quota
;
7391 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
7394 struct cfs_schedulable_data data
= {
7400 if (quota
!= RUNTIME_INF
) {
7401 do_div(data
.period
, NSEC_PER_USEC
);
7402 do_div(data
.quota
, NSEC_PER_USEC
);
7406 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
7412 static int cpu_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
7413 struct cgroup_map_cb
*cb
)
7415 struct task_group
*tg
= cgroup_tg(cgrp
);
7416 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7418 cb
->fill(cb
, "nr_periods", cfs_b
->nr_periods
);
7419 cb
->fill(cb
, "nr_throttled", cfs_b
->nr_throttled
);
7420 cb
->fill(cb
, "throttled_time", cfs_b
->throttled_time
);
7424 #endif /* CONFIG_CFS_BANDWIDTH */
7425 #endif /* CONFIG_FAIR_GROUP_SCHED */
7427 #ifdef CONFIG_RT_GROUP_SCHED
7428 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
7431 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
7434 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
7436 return sched_group_rt_runtime(cgroup_tg(cgrp
));
7439 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
7442 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
7445 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
7447 return sched_group_rt_period(cgroup_tg(cgrp
));
7449 #endif /* CONFIG_RT_GROUP_SCHED */
7451 static struct cftype cpu_files
[] = {
7452 #ifdef CONFIG_FAIR_GROUP_SCHED
7455 .read_u64
= cpu_shares_read_u64
,
7456 .write_u64
= cpu_shares_write_u64
,
7459 #ifdef CONFIG_CFS_BANDWIDTH
7461 .name
= "cfs_quota_us",
7462 .read_s64
= cpu_cfs_quota_read_s64
,
7463 .write_s64
= cpu_cfs_quota_write_s64
,
7466 .name
= "cfs_period_us",
7467 .read_u64
= cpu_cfs_period_read_u64
,
7468 .write_u64
= cpu_cfs_period_write_u64
,
7472 .read_map
= cpu_stats_show
,
7475 #ifdef CONFIG_RT_GROUP_SCHED
7477 .name
= "rt_runtime_us",
7478 .read_s64
= cpu_rt_runtime_read
,
7479 .write_s64
= cpu_rt_runtime_write
,
7482 .name
= "rt_period_us",
7483 .read_u64
= cpu_rt_period_read_uint
,
7484 .write_u64
= cpu_rt_period_write_uint
,
7490 struct cgroup_subsys cpu_cgroup_subsys
= {
7492 .css_alloc
= cpu_cgroup_css_alloc
,
7493 .css_free
= cpu_cgroup_css_free
,
7494 .css_online
= cpu_cgroup_css_online
,
7495 .css_offline
= cpu_cgroup_css_offline
,
7496 .can_attach
= cpu_cgroup_can_attach
,
7497 .attach
= cpu_cgroup_attach
,
7498 .exit
= cpu_cgroup_exit
,
7499 .subsys_id
= cpu_cgroup_subsys_id
,
7500 .base_cftypes
= cpu_files
,
7504 #endif /* CONFIG_CGROUP_SCHED */
7506 void dump_cpu_task(int cpu
)
7508 pr_info("Task dump for CPU %d:\n", cpu
);
7509 sched_show_task(cpu_curr(cpu
));