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_sched.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 */
197 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
198 size_t cnt
, loff_t
*ppos
)
208 if (copy_from_user(&buf
, ubuf
, cnt
))
214 if (strncmp(cmp
, "NO_", 3) == 0) {
219 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
220 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
222 sysctl_sched_features
&= ~(1UL << i
);
223 sched_feat_disable(i
);
225 sysctl_sched_features
|= (1UL << i
);
226 sched_feat_enable(i
);
232 if (i
== __SCHED_FEAT_NR
)
240 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
242 return single_open(filp
, sched_feat_show
, NULL
);
245 static const struct file_operations sched_feat_fops
= {
246 .open
= sched_feat_open
,
247 .write
= sched_feat_write
,
250 .release
= single_release
,
253 static __init
int sched_init_debug(void)
255 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
260 late_initcall(sched_init_debug
);
261 #endif /* CONFIG_SCHED_DEBUG */
264 * Number of tasks to iterate in a single balance run.
265 * Limited because this is done with IRQs disabled.
267 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
270 * period over which we average the RT time consumption, measured
275 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
278 * period over which we measure -rt task cpu usage in us.
281 unsigned int sysctl_sched_rt_period
= 1000000;
283 __read_mostly
int scheduler_running
;
286 * part of the period that we allow rt tasks to run in us.
289 int sysctl_sched_rt_runtime
= 950000;
294 * __task_rq_lock - lock the rq @p resides on.
296 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
301 lockdep_assert_held(&p
->pi_lock
);
305 raw_spin_lock(&rq
->lock
);
306 if (likely(rq
== task_rq(p
)))
308 raw_spin_unlock(&rq
->lock
);
313 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
315 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
316 __acquires(p
->pi_lock
)
322 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
324 raw_spin_lock(&rq
->lock
);
325 if (likely(rq
== task_rq(p
)))
327 raw_spin_unlock(&rq
->lock
);
328 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
332 static void __task_rq_unlock(struct rq
*rq
)
335 raw_spin_unlock(&rq
->lock
);
339 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
341 __releases(p
->pi_lock
)
343 raw_spin_unlock(&rq
->lock
);
344 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
348 * this_rq_lock - lock this runqueue and disable interrupts.
350 static struct rq
*this_rq_lock(void)
357 raw_spin_lock(&rq
->lock
);
362 #ifdef CONFIG_SCHED_HRTICK
364 * Use HR-timers to deliver accurate preemption points.
366 * Its all a bit involved since we cannot program an hrt while holding the
367 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
370 * When we get rescheduled we reprogram the hrtick_timer outside of the
374 static void hrtick_clear(struct rq
*rq
)
376 if (hrtimer_active(&rq
->hrtick_timer
))
377 hrtimer_cancel(&rq
->hrtick_timer
);
381 * High-resolution timer tick.
382 * Runs from hardirq context with interrupts disabled.
384 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
386 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
388 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
390 raw_spin_lock(&rq
->lock
);
392 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
393 raw_spin_unlock(&rq
->lock
);
395 return HRTIMER_NORESTART
;
400 * called from hardirq (IPI) context
402 static void __hrtick_start(void *arg
)
406 raw_spin_lock(&rq
->lock
);
407 hrtimer_restart(&rq
->hrtick_timer
);
408 rq
->hrtick_csd_pending
= 0;
409 raw_spin_unlock(&rq
->lock
);
413 * Called to set the hrtick timer state.
415 * called with rq->lock held and irqs disabled
417 void hrtick_start(struct rq
*rq
, u64 delay
)
419 struct hrtimer
*timer
= &rq
->hrtick_timer
;
420 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
422 hrtimer_set_expires(timer
, time
);
424 if (rq
== this_rq()) {
425 hrtimer_restart(timer
);
426 } else if (!rq
->hrtick_csd_pending
) {
427 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
428 rq
->hrtick_csd_pending
= 1;
433 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
435 int cpu
= (int)(long)hcpu
;
438 case CPU_UP_CANCELED
:
439 case CPU_UP_CANCELED_FROZEN
:
440 case CPU_DOWN_PREPARE
:
441 case CPU_DOWN_PREPARE_FROZEN
:
443 case CPU_DEAD_FROZEN
:
444 hrtick_clear(cpu_rq(cpu
));
451 static __init
void init_hrtick(void)
453 hotcpu_notifier(hotplug_hrtick
, 0);
457 * Called to set the hrtick timer state.
459 * called with rq->lock held and irqs disabled
461 void hrtick_start(struct rq
*rq
, u64 delay
)
463 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
464 HRTIMER_MODE_REL_PINNED
, 0);
467 static inline void init_hrtick(void)
470 #endif /* CONFIG_SMP */
472 static void init_rq_hrtick(struct rq
*rq
)
475 rq
->hrtick_csd_pending
= 0;
477 rq
->hrtick_csd
.flags
= 0;
478 rq
->hrtick_csd
.func
= __hrtick_start
;
479 rq
->hrtick_csd
.info
= rq
;
482 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
483 rq
->hrtick_timer
.function
= hrtick
;
485 #else /* CONFIG_SCHED_HRTICK */
486 static inline void hrtick_clear(struct rq
*rq
)
490 static inline void init_rq_hrtick(struct rq
*rq
)
494 static inline void init_hrtick(void)
497 #endif /* CONFIG_SCHED_HRTICK */
500 * resched_task - mark a task 'to be rescheduled now'.
502 * On UP this means the setting of the need_resched flag, on SMP it
503 * might also involve a cross-CPU call to trigger the scheduler on
508 #ifndef tsk_is_polling
509 #define tsk_is_polling(t) 0
512 void resched_task(struct task_struct
*p
)
516 assert_raw_spin_locked(&task_rq(p
)->lock
);
518 if (test_tsk_need_resched(p
))
521 set_tsk_need_resched(p
);
524 if (cpu
== smp_processor_id())
527 /* NEED_RESCHED must be visible before we test polling */
529 if (!tsk_is_polling(p
))
530 smp_send_reschedule(cpu
);
533 void resched_cpu(int cpu
)
535 struct rq
*rq
= cpu_rq(cpu
);
538 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
540 resched_task(cpu_curr(cpu
));
541 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
546 * In the semi idle case, use the nearest busy cpu for migrating timers
547 * from an idle cpu. This is good for power-savings.
549 * We don't do similar optimization for completely idle system, as
550 * selecting an idle cpu will add more delays to the timers than intended
551 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
553 int get_nohz_timer_target(void)
555 int cpu
= smp_processor_id();
557 struct sched_domain
*sd
;
560 for_each_domain(cpu
, sd
) {
561 for_each_cpu(i
, sched_domain_span(sd
)) {
573 * When add_timer_on() enqueues a timer into the timer wheel of an
574 * idle CPU then this timer might expire before the next timer event
575 * which is scheduled to wake up that CPU. In case of a completely
576 * idle system the next event might even be infinite time into the
577 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
578 * leaves the inner idle loop so the newly added timer is taken into
579 * account when the CPU goes back to idle and evaluates the timer
580 * wheel for the next timer event.
582 void wake_up_idle_cpu(int cpu
)
584 struct rq
*rq
= cpu_rq(cpu
);
586 if (cpu
== smp_processor_id())
590 * This is safe, as this function is called with the timer
591 * wheel base lock of (cpu) held. When the CPU is on the way
592 * to idle and has not yet set rq->curr to idle then it will
593 * be serialized on the timer wheel base lock and take the new
594 * timer into account automatically.
596 if (rq
->curr
!= rq
->idle
)
600 * We can set TIF_RESCHED on the idle task of the other CPU
601 * lockless. The worst case is that the other CPU runs the
602 * idle task through an additional NOOP schedule()
604 set_tsk_need_resched(rq
->idle
);
606 /* NEED_RESCHED must be visible before we test polling */
608 if (!tsk_is_polling(rq
->idle
))
609 smp_send_reschedule(cpu
);
612 static inline bool got_nohz_idle_kick(void)
614 int cpu
= smp_processor_id();
615 return idle_cpu(cpu
) && test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
618 #else /* CONFIG_NO_HZ */
620 static inline bool got_nohz_idle_kick(void)
625 #endif /* CONFIG_NO_HZ */
627 void sched_avg_update(struct rq
*rq
)
629 s64 period
= sched_avg_period();
631 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
633 * Inline assembly required to prevent the compiler
634 * optimising this loop into a divmod call.
635 * See __iter_div_u64_rem() for another example of this.
637 asm("" : "+rm" (rq
->age_stamp
));
638 rq
->age_stamp
+= period
;
643 #else /* !CONFIG_SMP */
644 void resched_task(struct task_struct
*p
)
646 assert_raw_spin_locked(&task_rq(p
)->lock
);
647 set_tsk_need_resched(p
);
649 #endif /* CONFIG_SMP */
651 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
652 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
654 * Iterate task_group tree rooted at *from, calling @down when first entering a
655 * node and @up when leaving it for the final time.
657 * Caller must hold rcu_lock or sufficient equivalent.
659 int walk_tg_tree_from(struct task_group
*from
,
660 tg_visitor down
, tg_visitor up
, void *data
)
662 struct task_group
*parent
, *child
;
668 ret
= (*down
)(parent
, data
);
671 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
678 ret
= (*up
)(parent
, data
);
679 if (ret
|| parent
== from
)
683 parent
= parent
->parent
;
690 int tg_nop(struct task_group
*tg
, void *data
)
696 static void set_load_weight(struct task_struct
*p
)
698 int prio
= p
->static_prio
- MAX_RT_PRIO
;
699 struct load_weight
*load
= &p
->se
.load
;
702 * SCHED_IDLE tasks get minimal weight:
704 if (p
->policy
== SCHED_IDLE
) {
705 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
706 load
->inv_weight
= WMULT_IDLEPRIO
;
710 load
->weight
= scale_load(prio_to_weight
[prio
]);
711 load
->inv_weight
= prio_to_wmult
[prio
];
714 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
717 sched_info_queued(p
);
718 p
->sched_class
->enqueue_task(rq
, p
, flags
);
721 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
724 sched_info_dequeued(p
);
725 p
->sched_class
->dequeue_task(rq
, p
, flags
);
728 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
730 if (task_contributes_to_load(p
))
731 rq
->nr_uninterruptible
--;
733 enqueue_task(rq
, p
, flags
);
736 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
738 if (task_contributes_to_load(p
))
739 rq
->nr_uninterruptible
++;
741 dequeue_task(rq
, p
, flags
);
744 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
747 * In theory, the compile should just see 0 here, and optimize out the call
748 * to sched_rt_avg_update. But I don't trust it...
750 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
751 s64 steal
= 0, irq_delta
= 0;
753 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
754 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
757 * Since irq_time is only updated on {soft,}irq_exit, we might run into
758 * this case when a previous update_rq_clock() happened inside a
761 * When this happens, we stop ->clock_task and only update the
762 * prev_irq_time stamp to account for the part that fit, so that a next
763 * update will consume the rest. This ensures ->clock_task is
766 * It does however cause some slight miss-attribution of {soft,}irq
767 * time, a more accurate solution would be to update the irq_time using
768 * the current rq->clock timestamp, except that would require using
771 if (irq_delta
> delta
)
774 rq
->prev_irq_time
+= irq_delta
;
777 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
778 if (static_key_false((¶virt_steal_rq_enabled
))) {
781 steal
= paravirt_steal_clock(cpu_of(rq
));
782 steal
-= rq
->prev_steal_time_rq
;
784 if (unlikely(steal
> delta
))
787 st
= steal_ticks(steal
);
788 steal
= st
* TICK_NSEC
;
790 rq
->prev_steal_time_rq
+= steal
;
796 rq
->clock_task
+= delta
;
798 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
799 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
800 sched_rt_avg_update(rq
, irq_delta
+ steal
);
804 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
806 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
807 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
811 * Make it appear like a SCHED_FIFO task, its something
812 * userspace knows about and won't get confused about.
814 * Also, it will make PI more or less work without too
815 * much confusion -- but then, stop work should not
816 * rely on PI working anyway.
818 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
820 stop
->sched_class
= &stop_sched_class
;
823 cpu_rq(cpu
)->stop
= stop
;
827 * Reset it back to a normal scheduling class so that
828 * it can die in pieces.
830 old_stop
->sched_class
= &rt_sched_class
;
835 * __normal_prio - return the priority that is based on the static prio
837 static inline int __normal_prio(struct task_struct
*p
)
839 return p
->static_prio
;
843 * Calculate the expected normal priority: i.e. priority
844 * without taking RT-inheritance into account. Might be
845 * boosted by interactivity modifiers. Changes upon fork,
846 * setprio syscalls, and whenever the interactivity
847 * estimator recalculates.
849 static inline int normal_prio(struct task_struct
*p
)
853 if (task_has_rt_policy(p
))
854 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
856 prio
= __normal_prio(p
);
861 * Calculate the current priority, i.e. the priority
862 * taken into account by the scheduler. This value might
863 * be boosted by RT tasks, or might be boosted by
864 * interactivity modifiers. Will be RT if the task got
865 * RT-boosted. If not then it returns p->normal_prio.
867 static int effective_prio(struct task_struct
*p
)
869 p
->normal_prio
= normal_prio(p
);
871 * If we are RT tasks or we were boosted to RT priority,
872 * keep the priority unchanged. Otherwise, update priority
873 * to the normal priority:
875 if (!rt_prio(p
->prio
))
876 return p
->normal_prio
;
881 * task_curr - is this task currently executing on a CPU?
882 * @p: the task in question.
884 inline int task_curr(const struct task_struct
*p
)
886 return cpu_curr(task_cpu(p
)) == p
;
889 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
890 const struct sched_class
*prev_class
,
893 if (prev_class
!= p
->sched_class
) {
894 if (prev_class
->switched_from
)
895 prev_class
->switched_from(rq
, p
);
896 p
->sched_class
->switched_to(rq
, p
);
897 } else if (oldprio
!= p
->prio
)
898 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
901 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
903 const struct sched_class
*class;
905 if (p
->sched_class
== rq
->curr
->sched_class
) {
906 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
908 for_each_class(class) {
909 if (class == rq
->curr
->sched_class
)
911 if (class == p
->sched_class
) {
912 resched_task(rq
->curr
);
919 * A queue event has occurred, and we're going to schedule. In
920 * this case, we can save a useless back to back clock update.
922 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
923 rq
->skip_clock_update
= 1;
926 static ATOMIC_NOTIFIER_HEAD(task_migration_notifier
);
928 void register_task_migration_notifier(struct notifier_block
*n
)
930 atomic_notifier_chain_register(&task_migration_notifier
, n
);
934 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
936 #ifdef CONFIG_SCHED_DEBUG
938 * We should never call set_task_cpu() on a blocked task,
939 * ttwu() will sort out the placement.
941 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
942 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
944 #ifdef CONFIG_LOCKDEP
946 * The caller should hold either p->pi_lock or rq->lock, when changing
947 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
949 * sched_move_task() holds both and thus holding either pins the cgroup,
952 * Furthermore, all task_rq users should acquire both locks, see
955 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
956 lockdep_is_held(&task_rq(p
)->lock
)));
960 trace_sched_migrate_task(p
, new_cpu
);
962 if (task_cpu(p
) != new_cpu
) {
963 struct task_migration_notifier tmn
;
965 if (p
->sched_class
->migrate_task_rq
)
966 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
967 p
->se
.nr_migrations
++;
968 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
971 tmn
.from_cpu
= task_cpu(p
);
972 tmn
.to_cpu
= new_cpu
;
974 atomic_notifier_call_chain(&task_migration_notifier
, 0, &tmn
);
977 __set_task_cpu(p
, new_cpu
);
980 struct migration_arg
{
981 struct task_struct
*task
;
985 static int migration_cpu_stop(void *data
);
988 * wait_task_inactive - wait for a thread to unschedule.
990 * If @match_state is nonzero, it's the @p->state value just checked and
991 * not expected to change. If it changes, i.e. @p might have woken up,
992 * then return zero. When we succeed in waiting for @p to be off its CPU,
993 * we return a positive number (its total switch count). If a second call
994 * a short while later returns the same number, the caller can be sure that
995 * @p has remained unscheduled the whole time.
997 * The caller must ensure that the task *will* unschedule sometime soon,
998 * else this function might spin for a *long* time. This function can't
999 * be called with interrupts off, or it may introduce deadlock with
1000 * smp_call_function() if an IPI is sent by the same process we are
1001 * waiting to become inactive.
1003 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1005 unsigned long flags
;
1012 * We do the initial early heuristics without holding
1013 * any task-queue locks at all. We'll only try to get
1014 * the runqueue lock when things look like they will
1020 * If the task is actively running on another CPU
1021 * still, just relax and busy-wait without holding
1024 * NOTE! Since we don't hold any locks, it's not
1025 * even sure that "rq" stays as the right runqueue!
1026 * But we don't care, since "task_running()" will
1027 * return false if the runqueue has changed and p
1028 * is actually now running somewhere else!
1030 while (task_running(rq
, p
)) {
1031 if (match_state
&& unlikely(p
->state
!= match_state
))
1037 * Ok, time to look more closely! We need the rq
1038 * lock now, to be *sure*. If we're wrong, we'll
1039 * just go back and repeat.
1041 rq
= task_rq_lock(p
, &flags
);
1042 trace_sched_wait_task(p
);
1043 running
= task_running(rq
, p
);
1046 if (!match_state
|| p
->state
== match_state
)
1047 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1048 task_rq_unlock(rq
, p
, &flags
);
1051 * If it changed from the expected state, bail out now.
1053 if (unlikely(!ncsw
))
1057 * Was it really running after all now that we
1058 * checked with the proper locks actually held?
1060 * Oops. Go back and try again..
1062 if (unlikely(running
)) {
1068 * It's not enough that it's not actively running,
1069 * it must be off the runqueue _entirely_, and not
1072 * So if it was still runnable (but just not actively
1073 * running right now), it's preempted, and we should
1074 * yield - it could be a while.
1076 if (unlikely(on_rq
)) {
1077 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1079 set_current_state(TASK_UNINTERRUPTIBLE
);
1080 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1085 * Ahh, all good. It wasn't running, and it wasn't
1086 * runnable, which means that it will never become
1087 * running in the future either. We're all done!
1096 * kick_process - kick a running thread to enter/exit the kernel
1097 * @p: the to-be-kicked thread
1099 * Cause a process which is running on another CPU to enter
1100 * kernel-mode, without any delay. (to get signals handled.)
1102 * NOTE: this function doesn't have to take the runqueue lock,
1103 * because all it wants to ensure is that the remote task enters
1104 * the kernel. If the IPI races and the task has been migrated
1105 * to another CPU then no harm is done and the purpose has been
1108 void kick_process(struct task_struct
*p
)
1114 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1115 smp_send_reschedule(cpu
);
1118 EXPORT_SYMBOL_GPL(kick_process
);
1119 #endif /* CONFIG_SMP */
1123 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1125 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1127 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
1128 enum { cpuset
, possible
, fail
} state
= cpuset
;
1131 /* Look for allowed, online CPU in same node. */
1132 for_each_cpu(dest_cpu
, nodemask
) {
1133 if (!cpu_online(dest_cpu
))
1135 if (!cpu_active(dest_cpu
))
1137 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1142 /* Any allowed, online CPU? */
1143 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1144 if (!cpu_online(dest_cpu
))
1146 if (!cpu_active(dest_cpu
))
1153 /* No more Mr. Nice Guy. */
1154 cpuset_cpus_allowed_fallback(p
);
1159 do_set_cpus_allowed(p
, cpu_possible_mask
);
1170 if (state
!= cpuset
) {
1172 * Don't tell them about moving exiting tasks or
1173 * kernel threads (both mm NULL), since they never
1176 if (p
->mm
&& printk_ratelimit()) {
1177 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1178 task_pid_nr(p
), p
->comm
, cpu
);
1186 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1189 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
1191 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
1194 * In order not to call set_task_cpu() on a blocking task we need
1195 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1198 * Since this is common to all placement strategies, this lives here.
1200 * [ this allows ->select_task() to simply return task_cpu(p) and
1201 * not worry about this generic constraint ]
1203 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1205 cpu
= select_fallback_rq(task_cpu(p
), p
);
1210 static void update_avg(u64
*avg
, u64 sample
)
1212 s64 diff
= sample
- *avg
;
1218 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1220 #ifdef CONFIG_SCHEDSTATS
1221 struct rq
*rq
= this_rq();
1224 int this_cpu
= smp_processor_id();
1226 if (cpu
== this_cpu
) {
1227 schedstat_inc(rq
, ttwu_local
);
1228 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1230 struct sched_domain
*sd
;
1232 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1234 for_each_domain(this_cpu
, sd
) {
1235 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1236 schedstat_inc(sd
, ttwu_wake_remote
);
1243 if (wake_flags
& WF_MIGRATED
)
1244 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1246 #endif /* CONFIG_SMP */
1248 schedstat_inc(rq
, ttwu_count
);
1249 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1251 if (wake_flags
& WF_SYNC
)
1252 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1254 #endif /* CONFIG_SCHEDSTATS */
1257 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1259 activate_task(rq
, p
, en_flags
);
1262 /* if a worker is waking up, notify workqueue */
1263 if (p
->flags
& PF_WQ_WORKER
)
1264 wq_worker_waking_up(p
, cpu_of(rq
));
1268 * Mark the task runnable and perform wakeup-preemption.
1271 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1273 trace_sched_wakeup(p
, true);
1274 check_preempt_curr(rq
, p
, wake_flags
);
1276 p
->state
= TASK_RUNNING
;
1278 if (p
->sched_class
->task_woken
)
1279 p
->sched_class
->task_woken(rq
, p
);
1281 if (rq
->idle_stamp
) {
1282 u64 delta
= rq
->clock
- rq
->idle_stamp
;
1283 u64 max
= 2*sysctl_sched_migration_cost
;
1288 update_avg(&rq
->avg_idle
, delta
);
1295 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1298 if (p
->sched_contributes_to_load
)
1299 rq
->nr_uninterruptible
--;
1302 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1303 ttwu_do_wakeup(rq
, p
, wake_flags
);
1307 * Called in case the task @p isn't fully descheduled from its runqueue,
1308 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1309 * since all we need to do is flip p->state to TASK_RUNNING, since
1310 * the task is still ->on_rq.
1312 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1317 rq
= __task_rq_lock(p
);
1319 ttwu_do_wakeup(rq
, p
, wake_flags
);
1322 __task_rq_unlock(rq
);
1328 static void sched_ttwu_pending(void)
1330 struct rq
*rq
= this_rq();
1331 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1332 struct task_struct
*p
;
1334 raw_spin_lock(&rq
->lock
);
1337 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1338 llist
= llist_next(llist
);
1339 ttwu_do_activate(rq
, p
, 0);
1342 raw_spin_unlock(&rq
->lock
);
1345 void scheduler_ipi(void)
1347 if (llist_empty(&this_rq()->wake_list
) && !got_nohz_idle_kick())
1351 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1352 * traditionally all their work was done from the interrupt return
1353 * path. Now that we actually do some work, we need to make sure
1356 * Some archs already do call them, luckily irq_enter/exit nest
1359 * Arguably we should visit all archs and update all handlers,
1360 * however a fair share of IPIs are still resched only so this would
1361 * somewhat pessimize the simple resched case.
1364 sched_ttwu_pending();
1367 * Check if someone kicked us for doing the nohz idle load balance.
1369 if (unlikely(got_nohz_idle_kick() && !need_resched())) {
1370 this_rq()->idle_balance
= 1;
1371 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1376 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1378 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
1379 smp_send_reschedule(cpu
);
1382 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1384 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1386 #endif /* CONFIG_SMP */
1388 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1390 struct rq
*rq
= cpu_rq(cpu
);
1392 #if defined(CONFIG_SMP)
1393 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1394 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1395 ttwu_queue_remote(p
, cpu
);
1400 raw_spin_lock(&rq
->lock
);
1401 ttwu_do_activate(rq
, p
, 0);
1402 raw_spin_unlock(&rq
->lock
);
1406 * try_to_wake_up - wake up a thread
1407 * @p: the thread to be awakened
1408 * @state: the mask of task states that can be woken
1409 * @wake_flags: wake modifier flags (WF_*)
1411 * Put it on the run-queue if it's not already there. The "current"
1412 * thread is always on the run-queue (except when the actual
1413 * re-schedule is in progress), and as such you're allowed to do
1414 * the simpler "current->state = TASK_RUNNING" to mark yourself
1415 * runnable without the overhead of this.
1417 * Returns %true if @p was woken up, %false if it was already running
1418 * or @state didn't match @p's state.
1421 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1423 unsigned long flags
;
1424 int cpu
, success
= 0;
1427 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1428 if (!(p
->state
& state
))
1431 success
= 1; /* we're going to change ->state */
1434 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1439 * If the owning (remote) cpu is still in the middle of schedule() with
1440 * this task as prev, wait until its done referencing the task.
1445 * Pairs with the smp_wmb() in finish_lock_switch().
1449 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1450 p
->state
= TASK_WAKING
;
1452 if (p
->sched_class
->task_waking
)
1453 p
->sched_class
->task_waking(p
);
1455 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
1456 if (task_cpu(p
) != cpu
) {
1457 wake_flags
|= WF_MIGRATED
;
1458 set_task_cpu(p
, cpu
);
1460 #endif /* CONFIG_SMP */
1464 ttwu_stat(p
, cpu
, wake_flags
);
1466 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1472 * try_to_wake_up_local - try to wake up a local task with rq lock held
1473 * @p: the thread to be awakened
1475 * Put @p on the run-queue if it's not already there. The caller must
1476 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1479 static void try_to_wake_up_local(struct task_struct
*p
)
1481 struct rq
*rq
= task_rq(p
);
1483 BUG_ON(rq
!= this_rq());
1484 BUG_ON(p
== current
);
1485 lockdep_assert_held(&rq
->lock
);
1487 if (!raw_spin_trylock(&p
->pi_lock
)) {
1488 raw_spin_unlock(&rq
->lock
);
1489 raw_spin_lock(&p
->pi_lock
);
1490 raw_spin_lock(&rq
->lock
);
1493 if (!(p
->state
& TASK_NORMAL
))
1497 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1499 ttwu_do_wakeup(rq
, p
, 0);
1500 ttwu_stat(p
, smp_processor_id(), 0);
1502 raw_spin_unlock(&p
->pi_lock
);
1506 * wake_up_process - Wake up a specific process
1507 * @p: The process to be woken up.
1509 * Attempt to wake up the nominated process and move it to the set of runnable
1510 * processes. Returns 1 if the process was woken up, 0 if it was already
1513 * It may be assumed that this function implies a write memory barrier before
1514 * changing the task state if and only if any tasks are woken up.
1516 int wake_up_process(struct task_struct
*p
)
1518 return try_to_wake_up(p
, TASK_ALL
, 0);
1520 EXPORT_SYMBOL(wake_up_process
);
1522 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1524 return try_to_wake_up(p
, state
, 0);
1528 * Perform scheduler related setup for a newly forked process p.
1529 * p is forked by current.
1531 * __sched_fork() is basic setup used by init_idle() too:
1533 static void __sched_fork(struct task_struct
*p
)
1538 p
->se
.exec_start
= 0;
1539 p
->se
.sum_exec_runtime
= 0;
1540 p
->se
.prev_sum_exec_runtime
= 0;
1541 p
->se
.nr_migrations
= 0;
1543 INIT_LIST_HEAD(&p
->se
.group_node
);
1546 * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
1547 * removed when useful for applications beyond shares distribution (e.g.
1550 #if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)
1551 p
->se
.avg
.runnable_avg_period
= 0;
1552 p
->se
.avg
.runnable_avg_sum
= 0;
1554 #ifdef CONFIG_SCHEDSTATS
1555 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1558 INIT_LIST_HEAD(&p
->rt
.run_list
);
1560 #ifdef CONFIG_PREEMPT_NOTIFIERS
1561 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1566 * fork()/clone()-time setup:
1568 void sched_fork(struct task_struct
*p
)
1570 unsigned long flags
;
1571 int cpu
= get_cpu();
1575 * We mark the process as running here. This guarantees that
1576 * nobody will actually run it, and a signal or other external
1577 * event cannot wake it up and insert it on the runqueue either.
1579 p
->state
= TASK_RUNNING
;
1582 * Make sure we do not leak PI boosting priority to the child.
1584 p
->prio
= current
->normal_prio
;
1587 * Revert to default priority/policy on fork if requested.
1589 if (unlikely(p
->sched_reset_on_fork
)) {
1590 if (task_has_rt_policy(p
)) {
1591 p
->policy
= SCHED_NORMAL
;
1592 p
->static_prio
= NICE_TO_PRIO(0);
1594 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1595 p
->static_prio
= NICE_TO_PRIO(0);
1597 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1601 * We don't need the reset flag anymore after the fork. It has
1602 * fulfilled its duty:
1604 p
->sched_reset_on_fork
= 0;
1607 if (!rt_prio(p
->prio
))
1608 p
->sched_class
= &fair_sched_class
;
1610 if (p
->sched_class
->task_fork
)
1611 p
->sched_class
->task_fork(p
);
1614 * The child is not yet in the pid-hash so no cgroup attach races,
1615 * and the cgroup is pinned to this child due to cgroup_fork()
1616 * is ran before sched_fork().
1618 * Silence PROVE_RCU.
1620 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1621 set_task_cpu(p
, cpu
);
1622 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1624 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1625 if (likely(sched_info_on()))
1626 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1628 #if defined(CONFIG_SMP)
1631 #ifdef CONFIG_PREEMPT_COUNT
1632 /* Want to start with kernel preemption disabled. */
1633 task_thread_info(p
)->preempt_count
= 1;
1636 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1643 * wake_up_new_task - wake up a newly created task for the first time.
1645 * This function will do some initial scheduler statistics housekeeping
1646 * that must be done for every newly created context, then puts the task
1647 * on the runqueue and wakes it.
1649 void wake_up_new_task(struct task_struct
*p
)
1651 unsigned long flags
;
1654 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1657 * Fork balancing, do it here and not earlier because:
1658 * - cpus_allowed can change in the fork path
1659 * - any previously selected cpu might disappear through hotplug
1661 set_task_cpu(p
, select_task_rq(p
, SD_BALANCE_FORK
, 0));
1664 rq
= __task_rq_lock(p
);
1665 activate_task(rq
, p
, 0);
1667 trace_sched_wakeup_new(p
, true);
1668 check_preempt_curr(rq
, p
, WF_FORK
);
1670 if (p
->sched_class
->task_woken
)
1671 p
->sched_class
->task_woken(rq
, p
);
1673 task_rq_unlock(rq
, p
, &flags
);
1676 #ifdef CONFIG_PREEMPT_NOTIFIERS
1679 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1680 * @notifier: notifier struct to register
1682 void preempt_notifier_register(struct preempt_notifier
*notifier
)
1684 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
1686 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
1689 * preempt_notifier_unregister - no longer interested in preemption notifications
1690 * @notifier: notifier struct to unregister
1692 * This is safe to call from within a preemption notifier.
1694 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
1696 hlist_del(¬ifier
->link
);
1698 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
1700 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1702 struct preempt_notifier
*notifier
;
1703 struct hlist_node
*node
;
1705 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
1706 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
1710 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1711 struct task_struct
*next
)
1713 struct preempt_notifier
*notifier
;
1714 struct hlist_node
*node
;
1716 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
1717 notifier
->ops
->sched_out(notifier
, next
);
1720 #else /* !CONFIG_PREEMPT_NOTIFIERS */
1722 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1727 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1728 struct task_struct
*next
)
1732 #endif /* CONFIG_PREEMPT_NOTIFIERS */
1735 * prepare_task_switch - prepare to switch tasks
1736 * @rq: the runqueue preparing to switch
1737 * @prev: the current task that is being switched out
1738 * @next: the task we are going to switch to.
1740 * This is called with the rq lock held and interrupts off. It must
1741 * be paired with a subsequent finish_task_switch after the context
1744 * prepare_task_switch sets up locking and calls architecture specific
1748 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
1749 struct task_struct
*next
)
1751 trace_sched_switch(prev
, next
);
1752 sched_info_switch(prev
, next
);
1753 perf_event_task_sched_out(prev
, next
);
1754 fire_sched_out_preempt_notifiers(prev
, next
);
1755 prepare_lock_switch(rq
, next
);
1756 prepare_arch_switch(next
);
1760 * finish_task_switch - clean up after a task-switch
1761 * @rq: runqueue associated with task-switch
1762 * @prev: the thread we just switched away from.
1764 * finish_task_switch must be called after the context switch, paired
1765 * with a prepare_task_switch call before the context switch.
1766 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1767 * and do any other architecture-specific cleanup actions.
1769 * Note that we may have delayed dropping an mm in context_switch(). If
1770 * so, we finish that here outside of the runqueue lock. (Doing it
1771 * with the lock held can cause deadlocks; see schedule() for
1774 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
1775 __releases(rq
->lock
)
1777 struct mm_struct
*mm
= rq
->prev_mm
;
1783 * A task struct has one reference for the use as "current".
1784 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1785 * schedule one last time. The schedule call will never return, and
1786 * the scheduled task must drop that reference.
1787 * The test for TASK_DEAD must occur while the runqueue locks are
1788 * still held, otherwise prev could be scheduled on another cpu, die
1789 * there before we look at prev->state, and then the reference would
1791 * Manfred Spraul <manfred@colorfullife.com>
1793 prev_state
= prev
->state
;
1794 vtime_task_switch(prev
);
1795 finish_arch_switch(prev
);
1796 perf_event_task_sched_in(prev
, current
);
1797 finish_lock_switch(rq
, prev
);
1798 finish_arch_post_lock_switch();
1800 fire_sched_in_preempt_notifiers(current
);
1803 if (unlikely(prev_state
== TASK_DEAD
)) {
1805 * Remove function-return probe instances associated with this
1806 * task and put them back on the free list.
1808 kprobe_flush_task(prev
);
1809 put_task_struct(prev
);
1815 /* assumes rq->lock is held */
1816 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
1818 if (prev
->sched_class
->pre_schedule
)
1819 prev
->sched_class
->pre_schedule(rq
, prev
);
1822 /* rq->lock is NOT held, but preemption is disabled */
1823 static inline void post_schedule(struct rq
*rq
)
1825 if (rq
->post_schedule
) {
1826 unsigned long flags
;
1828 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1829 if (rq
->curr
->sched_class
->post_schedule
)
1830 rq
->curr
->sched_class
->post_schedule(rq
);
1831 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1833 rq
->post_schedule
= 0;
1839 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
1843 static inline void post_schedule(struct rq
*rq
)
1850 * schedule_tail - first thing a freshly forked thread must call.
1851 * @prev: the thread we just switched away from.
1853 asmlinkage
void schedule_tail(struct task_struct
*prev
)
1854 __releases(rq
->lock
)
1856 struct rq
*rq
= this_rq();
1858 finish_task_switch(rq
, prev
);
1861 * FIXME: do we need to worry about rq being invalidated by the
1866 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
1867 /* In this case, finish_task_switch does not reenable preemption */
1870 if (current
->set_child_tid
)
1871 put_user(task_pid_vnr(current
), current
->set_child_tid
);
1875 * context_switch - switch to the new MM and the new
1876 * thread's register state.
1879 context_switch(struct rq
*rq
, struct task_struct
*prev
,
1880 struct task_struct
*next
)
1882 struct mm_struct
*mm
, *oldmm
;
1884 prepare_task_switch(rq
, prev
, next
);
1887 oldmm
= prev
->active_mm
;
1889 * For paravirt, this is coupled with an exit in switch_to to
1890 * combine the page table reload and the switch backend into
1893 arch_start_context_switch(prev
);
1896 next
->active_mm
= oldmm
;
1897 atomic_inc(&oldmm
->mm_count
);
1898 enter_lazy_tlb(oldmm
, next
);
1900 switch_mm(oldmm
, mm
, next
);
1903 prev
->active_mm
= NULL
;
1904 rq
->prev_mm
= oldmm
;
1907 * Since the runqueue lock will be released by the next
1908 * task (which is an invalid locking op but in the case
1909 * of the scheduler it's an obvious special-case), so we
1910 * do an early lockdep release here:
1912 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
1913 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
1916 context_tracking_task_switch(prev
, next
);
1917 /* Here we just switch the register state and the stack. */
1918 switch_to(prev
, next
, prev
);
1922 * this_rq must be evaluated again because prev may have moved
1923 * CPUs since it called schedule(), thus the 'rq' on its stack
1924 * frame will be invalid.
1926 finish_task_switch(this_rq(), prev
);
1930 * nr_running, nr_uninterruptible and nr_context_switches:
1932 * externally visible scheduler statistics: current number of runnable
1933 * threads, current number of uninterruptible-sleeping threads, total
1934 * number of context switches performed since bootup.
1936 unsigned long nr_running(void)
1938 unsigned long i
, sum
= 0;
1940 for_each_online_cpu(i
)
1941 sum
+= cpu_rq(i
)->nr_running
;
1946 unsigned long nr_uninterruptible(void)
1948 unsigned long i
, sum
= 0;
1950 for_each_possible_cpu(i
)
1951 sum
+= cpu_rq(i
)->nr_uninterruptible
;
1954 * Since we read the counters lockless, it might be slightly
1955 * inaccurate. Do not allow it to go below zero though:
1957 if (unlikely((long)sum
< 0))
1963 unsigned long long nr_context_switches(void)
1966 unsigned long long sum
= 0;
1968 for_each_possible_cpu(i
)
1969 sum
+= cpu_rq(i
)->nr_switches
;
1974 unsigned long nr_iowait(void)
1976 unsigned long i
, sum
= 0;
1978 for_each_possible_cpu(i
)
1979 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
1984 unsigned long nr_iowait_cpu(int cpu
)
1986 struct rq
*this = cpu_rq(cpu
);
1987 return atomic_read(&this->nr_iowait
);
1990 unsigned long this_cpu_load(void)
1992 struct rq
*this = this_rq();
1993 return this->cpu_load
[0];
1998 * Global load-average calculations
2000 * We take a distributed and async approach to calculating the global load-avg
2001 * in order to minimize overhead.
2003 * The global load average is an exponentially decaying average of nr_running +
2004 * nr_uninterruptible.
2006 * Once every LOAD_FREQ:
2009 * for_each_possible_cpu(cpu)
2010 * nr_active += cpu_of(cpu)->nr_running + cpu_of(cpu)->nr_uninterruptible;
2012 * avenrun[n] = avenrun[0] * exp_n + nr_active * (1 - exp_n)
2014 * Due to a number of reasons the above turns in the mess below:
2016 * - for_each_possible_cpu() is prohibitively expensive on machines with
2017 * serious number of cpus, therefore we need to take a distributed approach
2018 * to calculating nr_active.
2020 * \Sum_i x_i(t) = \Sum_i x_i(t) - x_i(t_0) | x_i(t_0) := 0
2021 * = \Sum_i { \Sum_j=1 x_i(t_j) - x_i(t_j-1) }
2023 * So assuming nr_active := 0 when we start out -- true per definition, we
2024 * can simply take per-cpu deltas and fold those into a global accumulate
2025 * to obtain the same result. See calc_load_fold_active().
2027 * Furthermore, in order to avoid synchronizing all per-cpu delta folding
2028 * across the machine, we assume 10 ticks is sufficient time for every
2029 * cpu to have completed this task.
2031 * This places an upper-bound on the IRQ-off latency of the machine. Then
2032 * again, being late doesn't loose the delta, just wrecks the sample.
2034 * - cpu_rq()->nr_uninterruptible isn't accurately tracked per-cpu because
2035 * this would add another cross-cpu cacheline miss and atomic operation
2036 * to the wakeup path. Instead we increment on whatever cpu the task ran
2037 * when it went into uninterruptible state and decrement on whatever cpu
2038 * did the wakeup. This means that only the sum of nr_uninterruptible over
2039 * all cpus yields the correct result.
2041 * This covers the NO_HZ=n code, for extra head-aches, see the comment below.
2044 /* Variables and functions for calc_load */
2045 static atomic_long_t calc_load_tasks
;
2046 static unsigned long calc_load_update
;
2047 unsigned long avenrun
[3];
2048 EXPORT_SYMBOL(avenrun
); /* should be removed */
2051 * get_avenrun - get the load average array
2052 * @loads: pointer to dest load array
2053 * @offset: offset to add
2054 * @shift: shift count to shift the result left
2056 * These values are estimates at best, so no need for locking.
2058 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
2060 loads
[0] = (avenrun
[0] + offset
) << shift
;
2061 loads
[1] = (avenrun
[1] + offset
) << shift
;
2062 loads
[2] = (avenrun
[2] + offset
) << shift
;
2065 static long calc_load_fold_active(struct rq
*this_rq
)
2067 long nr_active
, delta
= 0;
2069 nr_active
= this_rq
->nr_running
;
2070 nr_active
+= (long) this_rq
->nr_uninterruptible
;
2072 if (nr_active
!= this_rq
->calc_load_active
) {
2073 delta
= nr_active
- this_rq
->calc_load_active
;
2074 this_rq
->calc_load_active
= nr_active
;
2081 * a1 = a0 * e + a * (1 - e)
2083 static unsigned long
2084 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
2087 load
+= active
* (FIXED_1
- exp
);
2088 load
+= 1UL << (FSHIFT
- 1);
2089 return load
>> FSHIFT
;
2094 * Handle NO_HZ for the global load-average.
2096 * Since the above described distributed algorithm to compute the global
2097 * load-average relies on per-cpu sampling from the tick, it is affected by
2100 * The basic idea is to fold the nr_active delta into a global idle-delta upon
2101 * entering NO_HZ state such that we can include this as an 'extra' cpu delta
2102 * when we read the global state.
2104 * Obviously reality has to ruin such a delightfully simple scheme:
2106 * - When we go NO_HZ idle during the window, we can negate our sample
2107 * contribution, causing under-accounting.
2109 * We avoid this by keeping two idle-delta counters and flipping them
2110 * when the window starts, thus separating old and new NO_HZ load.
2112 * The only trick is the slight shift in index flip for read vs write.
2116 * |-|-----------|-|-----------|-|-----------|-|
2117 * r:0 0 1 1 0 0 1 1 0
2118 * w:0 1 1 0 0 1 1 0 0
2120 * This ensures we'll fold the old idle contribution in this window while
2121 * accumlating the new one.
2123 * - When we wake up from NO_HZ idle during the window, we push up our
2124 * contribution, since we effectively move our sample point to a known
2127 * This is solved by pushing the window forward, and thus skipping the
2128 * sample, for this cpu (effectively using the idle-delta for this cpu which
2129 * was in effect at the time the window opened). This also solves the issue
2130 * of having to deal with a cpu having been in NOHZ idle for multiple
2131 * LOAD_FREQ intervals.
2133 * When making the ILB scale, we should try to pull this in as well.
2135 static atomic_long_t calc_load_idle
[2];
2136 static int calc_load_idx
;
2138 static inline int calc_load_write_idx(void)
2140 int idx
= calc_load_idx
;
2143 * See calc_global_nohz(), if we observe the new index, we also
2144 * need to observe the new update time.
2149 * If the folding window started, make sure we start writing in the
2152 if (!time_before(jiffies
, calc_load_update
))
2158 static inline int calc_load_read_idx(void)
2160 return calc_load_idx
& 1;
2163 void calc_load_enter_idle(void)
2165 struct rq
*this_rq
= this_rq();
2169 * We're going into NOHZ mode, if there's any pending delta, fold it
2170 * into the pending idle delta.
2172 delta
= calc_load_fold_active(this_rq
);
2174 int idx
= calc_load_write_idx();
2175 atomic_long_add(delta
, &calc_load_idle
[idx
]);
2179 void calc_load_exit_idle(void)
2181 struct rq
*this_rq
= this_rq();
2184 * If we're still before the sample window, we're done.
2186 if (time_before(jiffies
, this_rq
->calc_load_update
))
2190 * We woke inside or after the sample window, this means we're already
2191 * accounted through the nohz accounting, so skip the entire deal and
2192 * sync up for the next window.
2194 this_rq
->calc_load_update
= calc_load_update
;
2195 if (time_before(jiffies
, this_rq
->calc_load_update
+ 10))
2196 this_rq
->calc_load_update
+= LOAD_FREQ
;
2199 static long calc_load_fold_idle(void)
2201 int idx
= calc_load_read_idx();
2204 if (atomic_long_read(&calc_load_idle
[idx
]))
2205 delta
= atomic_long_xchg(&calc_load_idle
[idx
], 0);
2211 * fixed_power_int - compute: x^n, in O(log n) time
2213 * @x: base of the power
2214 * @frac_bits: fractional bits of @x
2215 * @n: power to raise @x to.
2217 * By exploiting the relation between the definition of the natural power
2218 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
2219 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
2220 * (where: n_i \elem {0, 1}, the binary vector representing n),
2221 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
2222 * of course trivially computable in O(log_2 n), the length of our binary
2225 static unsigned long
2226 fixed_power_int(unsigned long x
, unsigned int frac_bits
, unsigned int n
)
2228 unsigned long result
= 1UL << frac_bits
;
2233 result
+= 1UL << (frac_bits
- 1);
2234 result
>>= frac_bits
;
2240 x
+= 1UL << (frac_bits
- 1);
2248 * a1 = a0 * e + a * (1 - e)
2250 * a2 = a1 * e + a * (1 - e)
2251 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
2252 * = a0 * e^2 + a * (1 - e) * (1 + e)
2254 * a3 = a2 * e + a * (1 - e)
2255 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
2256 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
2260 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
2261 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
2262 * = a0 * e^n + a * (1 - e^n)
2264 * [1] application of the geometric series:
2267 * S_n := \Sum x^i = -------------
2270 static unsigned long
2271 calc_load_n(unsigned long load
, unsigned long exp
,
2272 unsigned long active
, unsigned int n
)
2275 return calc_load(load
, fixed_power_int(exp
, FSHIFT
, n
), active
);
2279 * NO_HZ can leave us missing all per-cpu ticks calling
2280 * calc_load_account_active(), but since an idle CPU folds its delta into
2281 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
2282 * in the pending idle delta if our idle period crossed a load cycle boundary.
2284 * Once we've updated the global active value, we need to apply the exponential
2285 * weights adjusted to the number of cycles missed.
2287 static void calc_global_nohz(void)
2289 long delta
, active
, n
;
2291 if (!time_before(jiffies
, calc_load_update
+ 10)) {
2293 * Catch-up, fold however many we are behind still
2295 delta
= jiffies
- calc_load_update
- 10;
2296 n
= 1 + (delta
/ LOAD_FREQ
);
2298 active
= atomic_long_read(&calc_load_tasks
);
2299 active
= active
> 0 ? active
* FIXED_1
: 0;
2301 avenrun
[0] = calc_load_n(avenrun
[0], EXP_1
, active
, n
);
2302 avenrun
[1] = calc_load_n(avenrun
[1], EXP_5
, active
, n
);
2303 avenrun
[2] = calc_load_n(avenrun
[2], EXP_15
, active
, n
);
2305 calc_load_update
+= n
* LOAD_FREQ
;
2309 * Flip the idle index...
2311 * Make sure we first write the new time then flip the index, so that
2312 * calc_load_write_idx() will see the new time when it reads the new
2313 * index, this avoids a double flip messing things up.
2318 #else /* !CONFIG_NO_HZ */
2320 static inline long calc_load_fold_idle(void) { return 0; }
2321 static inline void calc_global_nohz(void) { }
2323 #endif /* CONFIG_NO_HZ */
2326 * calc_load - update the avenrun load estimates 10 ticks after the
2327 * CPUs have updated calc_load_tasks.
2329 void calc_global_load(unsigned long ticks
)
2333 if (time_before(jiffies
, calc_load_update
+ 10))
2337 * Fold the 'old' idle-delta to include all NO_HZ cpus.
2339 delta
= calc_load_fold_idle();
2341 atomic_long_add(delta
, &calc_load_tasks
);
2343 active
= atomic_long_read(&calc_load_tasks
);
2344 active
= active
> 0 ? active
* FIXED_1
: 0;
2346 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
2347 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
2348 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
2350 calc_load_update
+= LOAD_FREQ
;
2353 * In case we idled for multiple LOAD_FREQ intervals, catch up in bulk.
2359 * Called from update_cpu_load() to periodically update this CPU's
2362 static void calc_load_account_active(struct rq
*this_rq
)
2366 if (time_before(jiffies
, this_rq
->calc_load_update
))
2369 delta
= calc_load_fold_active(this_rq
);
2371 atomic_long_add(delta
, &calc_load_tasks
);
2373 this_rq
->calc_load_update
+= LOAD_FREQ
;
2377 * End of global load-average stuff
2381 * The exact cpuload at various idx values, calculated at every tick would be
2382 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
2384 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
2385 * on nth tick when cpu may be busy, then we have:
2386 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2387 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
2389 * decay_load_missed() below does efficient calculation of
2390 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2391 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
2393 * The calculation is approximated on a 128 point scale.
2394 * degrade_zero_ticks is the number of ticks after which load at any
2395 * particular idx is approximated to be zero.
2396 * degrade_factor is a precomputed table, a row for each load idx.
2397 * Each column corresponds to degradation factor for a power of two ticks,
2398 * based on 128 point scale.
2400 * row 2, col 3 (=12) says that the degradation at load idx 2 after
2401 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
2403 * With this power of 2 load factors, we can degrade the load n times
2404 * by looking at 1 bits in n and doing as many mult/shift instead of
2405 * n mult/shifts needed by the exact degradation.
2407 #define DEGRADE_SHIFT 7
2408 static const unsigned char
2409 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
2410 static const unsigned char
2411 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
2412 {0, 0, 0, 0, 0, 0, 0, 0},
2413 {64, 32, 8, 0, 0, 0, 0, 0},
2414 {96, 72, 40, 12, 1, 0, 0},
2415 {112, 98, 75, 43, 15, 1, 0},
2416 {120, 112, 98, 76, 45, 16, 2} };
2419 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
2420 * would be when CPU is idle and so we just decay the old load without
2421 * adding any new load.
2423 static unsigned long
2424 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
2428 if (!missed_updates
)
2431 if (missed_updates
>= degrade_zero_ticks
[idx
])
2435 return load
>> missed_updates
;
2437 while (missed_updates
) {
2438 if (missed_updates
% 2)
2439 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
2441 missed_updates
>>= 1;
2448 * Update rq->cpu_load[] statistics. This function is usually called every
2449 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
2450 * every tick. We fix it up based on jiffies.
2452 static void __update_cpu_load(struct rq
*this_rq
, unsigned long this_load
,
2453 unsigned long pending_updates
)
2457 this_rq
->nr_load_updates
++;
2459 /* Update our load: */
2460 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
2461 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2462 unsigned long old_load
, new_load
;
2464 /* scale is effectively 1 << i now, and >> i divides by scale */
2466 old_load
= this_rq
->cpu_load
[i
];
2467 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
2468 new_load
= this_load
;
2470 * Round up the averaging division if load is increasing. This
2471 * prevents us from getting stuck on 9 if the load is 10, for
2474 if (new_load
> old_load
)
2475 new_load
+= scale
- 1;
2477 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
2480 sched_avg_update(this_rq
);
2485 * There is no sane way to deal with nohz on smp when using jiffies because the
2486 * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading
2487 * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}.
2489 * Therefore we cannot use the delta approach from the regular tick since that
2490 * would seriously skew the load calculation. However we'll make do for those
2491 * updates happening while idle (nohz_idle_balance) or coming out of idle
2492 * (tick_nohz_idle_exit).
2494 * This means we might still be one tick off for nohz periods.
2498 * Called from nohz_idle_balance() to update the load ratings before doing the
2501 void update_idle_cpu_load(struct rq
*this_rq
)
2503 unsigned long curr_jiffies
= ACCESS_ONCE(jiffies
);
2504 unsigned long load
= this_rq
->load
.weight
;
2505 unsigned long pending_updates
;
2508 * bail if there's load or we're actually up-to-date.
2510 if (load
|| curr_jiffies
== this_rq
->last_load_update_tick
)
2513 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
2514 this_rq
->last_load_update_tick
= curr_jiffies
;
2516 __update_cpu_load(this_rq
, load
, pending_updates
);
2520 * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed.
2522 void update_cpu_load_nohz(void)
2524 struct rq
*this_rq
= this_rq();
2525 unsigned long curr_jiffies
= ACCESS_ONCE(jiffies
);
2526 unsigned long pending_updates
;
2528 if (curr_jiffies
== this_rq
->last_load_update_tick
)
2531 raw_spin_lock(&this_rq
->lock
);
2532 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
2533 if (pending_updates
) {
2534 this_rq
->last_load_update_tick
= curr_jiffies
;
2536 * We were idle, this means load 0, the current load might be
2537 * !0 due to remote wakeups and the sort.
2539 __update_cpu_load(this_rq
, 0, pending_updates
);
2541 raw_spin_unlock(&this_rq
->lock
);
2543 #endif /* CONFIG_NO_HZ */
2546 * Called from scheduler_tick()
2548 static void update_cpu_load_active(struct rq
*this_rq
)
2551 * See the mess around update_idle_cpu_load() / update_cpu_load_nohz().
2553 this_rq
->last_load_update_tick
= jiffies
;
2554 __update_cpu_load(this_rq
, this_rq
->load
.weight
, 1);
2556 calc_load_account_active(this_rq
);
2562 * sched_exec - execve() is a valuable balancing opportunity, because at
2563 * this point the task has the smallest effective memory and cache footprint.
2565 void sched_exec(void)
2567 struct task_struct
*p
= current
;
2568 unsigned long flags
;
2571 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2572 dest_cpu
= p
->sched_class
->select_task_rq(p
, SD_BALANCE_EXEC
, 0);
2573 if (dest_cpu
== smp_processor_id())
2576 if (likely(cpu_active(dest_cpu
))) {
2577 struct migration_arg arg
= { p
, dest_cpu
};
2579 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2580 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2584 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2589 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2590 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2592 EXPORT_PER_CPU_SYMBOL(kstat
);
2593 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2596 * Return any ns on the sched_clock that have not yet been accounted in
2597 * @p in case that task is currently running.
2599 * Called with task_rq_lock() held on @rq.
2601 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2605 if (task_current(rq
, p
)) {
2606 update_rq_clock(rq
);
2607 ns
= rq
->clock_task
- p
->se
.exec_start
;
2615 unsigned long long task_delta_exec(struct task_struct
*p
)
2617 unsigned long flags
;
2621 rq
= task_rq_lock(p
, &flags
);
2622 ns
= do_task_delta_exec(p
, rq
);
2623 task_rq_unlock(rq
, p
, &flags
);
2629 * Return accounted runtime for the task.
2630 * In case the task is currently running, return the runtime plus current's
2631 * pending runtime that have not been accounted yet.
2633 unsigned long long task_sched_runtime(struct task_struct
*p
)
2635 unsigned long flags
;
2639 rq
= task_rq_lock(p
, &flags
);
2640 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2641 task_rq_unlock(rq
, p
, &flags
);
2647 * This function gets called by the timer code, with HZ frequency.
2648 * We call it with interrupts disabled.
2650 void scheduler_tick(void)
2652 int cpu
= smp_processor_id();
2653 struct rq
*rq
= cpu_rq(cpu
);
2654 struct task_struct
*curr
= rq
->curr
;
2658 raw_spin_lock(&rq
->lock
);
2659 update_rq_clock(rq
);
2660 update_cpu_load_active(rq
);
2661 curr
->sched_class
->task_tick(rq
, curr
, 0);
2662 raw_spin_unlock(&rq
->lock
);
2664 perf_event_task_tick();
2667 rq
->idle_balance
= idle_cpu(cpu
);
2668 trigger_load_balance(rq
, cpu
);
2672 notrace
unsigned long get_parent_ip(unsigned long addr
)
2674 if (in_lock_functions(addr
)) {
2675 addr
= CALLER_ADDR2
;
2676 if (in_lock_functions(addr
))
2677 addr
= CALLER_ADDR3
;
2682 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2683 defined(CONFIG_PREEMPT_TRACER))
2685 void __kprobes
add_preempt_count(int val
)
2687 #ifdef CONFIG_DEBUG_PREEMPT
2691 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2694 preempt_count() += val
;
2695 #ifdef CONFIG_DEBUG_PREEMPT
2697 * Spinlock count overflowing soon?
2699 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2702 if (preempt_count() == val
)
2703 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2705 EXPORT_SYMBOL(add_preempt_count
);
2707 void __kprobes
sub_preempt_count(int val
)
2709 #ifdef CONFIG_DEBUG_PREEMPT
2713 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2716 * Is the spinlock portion underflowing?
2718 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2719 !(preempt_count() & PREEMPT_MASK
)))
2723 if (preempt_count() == val
)
2724 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2725 preempt_count() -= val
;
2727 EXPORT_SYMBOL(sub_preempt_count
);
2732 * Print scheduling while atomic bug:
2734 static noinline
void __schedule_bug(struct task_struct
*prev
)
2736 if (oops_in_progress
)
2739 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2740 prev
->comm
, prev
->pid
, preempt_count());
2742 debug_show_held_locks(prev
);
2744 if (irqs_disabled())
2745 print_irqtrace_events(prev
);
2747 add_taint(TAINT_WARN
);
2751 * Various schedule()-time debugging checks and statistics:
2753 static inline void schedule_debug(struct task_struct
*prev
)
2756 * Test if we are atomic. Since do_exit() needs to call into
2757 * schedule() atomically, we ignore that path for now.
2758 * Otherwise, whine if we are scheduling when we should not be.
2760 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
2761 __schedule_bug(prev
);
2764 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2766 schedstat_inc(this_rq(), sched_count
);
2769 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
2771 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
2772 update_rq_clock(rq
);
2773 prev
->sched_class
->put_prev_task(rq
, prev
);
2777 * Pick up the highest-prio task:
2779 static inline struct task_struct
*
2780 pick_next_task(struct rq
*rq
)
2782 const struct sched_class
*class;
2783 struct task_struct
*p
;
2786 * Optimization: we know that if all tasks are in
2787 * the fair class we can call that function directly:
2789 if (likely(rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2790 p
= fair_sched_class
.pick_next_task(rq
);
2795 for_each_class(class) {
2796 p
= class->pick_next_task(rq
);
2801 BUG(); /* the idle class will always have a runnable task */
2805 * __schedule() is the main scheduler function.
2807 * The main means of driving the scheduler and thus entering this function are:
2809 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2811 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2812 * paths. For example, see arch/x86/entry_64.S.
2814 * To drive preemption between tasks, the scheduler sets the flag in timer
2815 * interrupt handler scheduler_tick().
2817 * 3. Wakeups don't really cause entry into schedule(). They add a
2818 * task to the run-queue and that's it.
2820 * Now, if the new task added to the run-queue preempts the current
2821 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2822 * called on the nearest possible occasion:
2824 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2826 * - in syscall or exception context, at the next outmost
2827 * preempt_enable(). (this might be as soon as the wake_up()'s
2830 * - in IRQ context, return from interrupt-handler to
2831 * preemptible context
2833 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2836 * - cond_resched() call
2837 * - explicit schedule() call
2838 * - return from syscall or exception to user-space
2839 * - return from interrupt-handler to user-space
2841 static void __sched
__schedule(void)
2843 struct task_struct
*prev
, *next
;
2844 unsigned long *switch_count
;
2850 cpu
= smp_processor_id();
2852 rcu_note_context_switch(cpu
);
2855 schedule_debug(prev
);
2857 if (sched_feat(HRTICK
))
2860 raw_spin_lock_irq(&rq
->lock
);
2862 switch_count
= &prev
->nivcsw
;
2863 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2864 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2865 prev
->state
= TASK_RUNNING
;
2867 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2871 * If a worker went to sleep, notify and ask workqueue
2872 * whether it wants to wake up a task to maintain
2875 if (prev
->flags
& PF_WQ_WORKER
) {
2876 struct task_struct
*to_wakeup
;
2878 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2880 try_to_wake_up_local(to_wakeup
);
2883 switch_count
= &prev
->nvcsw
;
2886 pre_schedule(rq
, prev
);
2888 if (unlikely(!rq
->nr_running
))
2889 idle_balance(cpu
, rq
);
2891 put_prev_task(rq
, prev
);
2892 next
= pick_next_task(rq
);
2893 clear_tsk_need_resched(prev
);
2894 rq
->skip_clock_update
= 0;
2896 if (likely(prev
!= next
)) {
2901 context_switch(rq
, prev
, next
); /* unlocks the rq */
2903 * The context switch have flipped the stack from under us
2904 * and restored the local variables which were saved when
2905 * this task called schedule() in the past. prev == current
2906 * is still correct, but it can be moved to another cpu/rq.
2908 cpu
= smp_processor_id();
2911 raw_spin_unlock_irq(&rq
->lock
);
2915 sched_preempt_enable_no_resched();
2920 static inline void sched_submit_work(struct task_struct
*tsk
)
2922 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2925 * If we are going to sleep and we have plugged IO queued,
2926 * make sure to submit it to avoid deadlocks.
2928 if (blk_needs_flush_plug(tsk
))
2929 blk_schedule_flush_plug(tsk
);
2932 asmlinkage
void __sched
schedule(void)
2934 struct task_struct
*tsk
= current
;
2936 sched_submit_work(tsk
);
2939 EXPORT_SYMBOL(schedule
);
2941 #ifdef CONFIG_CONTEXT_TRACKING
2942 asmlinkage
void __sched
schedule_user(void)
2945 * If we come here after a random call to set_need_resched(),
2946 * or we have been woken up remotely but the IPI has not yet arrived,
2947 * we haven't yet exited the RCU idle mode. Do it here manually until
2948 * we find a better solution.
2957 * schedule_preempt_disabled - called with preemption disabled
2959 * Returns with preemption disabled. Note: preempt_count must be 1
2961 void __sched
schedule_preempt_disabled(void)
2963 sched_preempt_enable_no_resched();
2968 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
2970 static inline bool owner_running(struct mutex
*lock
, struct task_struct
*owner
)
2972 if (lock
->owner
!= owner
)
2976 * Ensure we emit the owner->on_cpu, dereference _after_ checking
2977 * lock->owner still matches owner, if that fails, owner might
2978 * point to free()d memory, if it still matches, the rcu_read_lock()
2979 * ensures the memory stays valid.
2983 return owner
->on_cpu
;
2987 * Look out! "owner" is an entirely speculative pointer
2988 * access and not reliable.
2990 int mutex_spin_on_owner(struct mutex
*lock
, struct task_struct
*owner
)
2992 if (!sched_feat(OWNER_SPIN
))
2996 while (owner_running(lock
, owner
)) {
3000 arch_mutex_cpu_relax();
3005 * We break out the loop above on need_resched() and when the
3006 * owner changed, which is a sign for heavy contention. Return
3007 * success only when lock->owner is NULL.
3009 return lock
->owner
== NULL
;
3013 #ifdef CONFIG_PREEMPT
3015 * this is the entry point to schedule() from in-kernel preemption
3016 * off of preempt_enable. Kernel preemptions off return from interrupt
3017 * occur there and call schedule directly.
3019 asmlinkage
void __sched notrace
preempt_schedule(void)
3021 struct thread_info
*ti
= current_thread_info();
3024 * If there is a non-zero preempt_count or interrupts are disabled,
3025 * we do not want to preempt the current task. Just return..
3027 if (likely(ti
->preempt_count
|| irqs_disabled()))
3031 add_preempt_count_notrace(PREEMPT_ACTIVE
);
3033 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
3036 * Check again in case we missed a preemption opportunity
3037 * between schedule and now.
3040 } while (need_resched());
3042 EXPORT_SYMBOL(preempt_schedule
);
3045 * this is the entry point to schedule() from kernel preemption
3046 * off of irq context.
3047 * Note, that this is called and return with irqs disabled. This will
3048 * protect us against recursive calling from irq.
3050 asmlinkage
void __sched
preempt_schedule_irq(void)
3052 struct thread_info
*ti
= current_thread_info();
3054 /* Catch callers which need to be fixed */
3055 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
3059 add_preempt_count(PREEMPT_ACTIVE
);
3062 local_irq_disable();
3063 sub_preempt_count(PREEMPT_ACTIVE
);
3066 * Check again in case we missed a preemption opportunity
3067 * between schedule and now.
3070 } while (need_resched());
3073 #endif /* CONFIG_PREEMPT */
3075 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
3078 return try_to_wake_up(curr
->private, mode
, wake_flags
);
3080 EXPORT_SYMBOL(default_wake_function
);
3083 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3084 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3085 * number) then we wake all the non-exclusive tasks and one exclusive task.
3087 * There are circumstances in which we can try to wake a task which has already
3088 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3089 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3091 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
3092 int nr_exclusive
, int wake_flags
, void *key
)
3094 wait_queue_t
*curr
, *next
;
3096 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
3097 unsigned flags
= curr
->flags
;
3099 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
3100 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
3106 * __wake_up - wake up threads blocked on a waitqueue.
3108 * @mode: which threads
3109 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3110 * @key: is directly passed to the wakeup function
3112 * It may be assumed that this function implies a write memory barrier before
3113 * changing the task state if and only if any tasks are woken up.
3115 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
3116 int nr_exclusive
, void *key
)
3118 unsigned long flags
;
3120 spin_lock_irqsave(&q
->lock
, flags
);
3121 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
3122 spin_unlock_irqrestore(&q
->lock
, flags
);
3124 EXPORT_SYMBOL(__wake_up
);
3127 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3129 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
, int nr
)
3131 __wake_up_common(q
, mode
, nr
, 0, NULL
);
3133 EXPORT_SYMBOL_GPL(__wake_up_locked
);
3135 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
3137 __wake_up_common(q
, mode
, 1, 0, key
);
3139 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
3142 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
3144 * @mode: which threads
3145 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3146 * @key: opaque value to be passed to wakeup targets
3148 * The sync wakeup differs that the waker knows that it will schedule
3149 * away soon, so while the target thread will be woken up, it will not
3150 * be migrated to another CPU - ie. the two threads are 'synchronized'
3151 * with each other. This can prevent needless bouncing between CPUs.
3153 * On UP it can prevent extra preemption.
3155 * It may be assumed that this function implies a write memory barrier before
3156 * changing the task state if and only if any tasks are woken up.
3158 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
3159 int nr_exclusive
, void *key
)
3161 unsigned long flags
;
3162 int wake_flags
= WF_SYNC
;
3167 if (unlikely(!nr_exclusive
))
3170 spin_lock_irqsave(&q
->lock
, flags
);
3171 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
3172 spin_unlock_irqrestore(&q
->lock
, flags
);
3174 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
3177 * __wake_up_sync - see __wake_up_sync_key()
3179 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
3181 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
3183 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
3186 * complete: - signals a single thread waiting on this completion
3187 * @x: holds the state of this particular completion
3189 * This will wake up a single thread waiting on this completion. Threads will be
3190 * awakened in the same order in which they were queued.
3192 * See also complete_all(), wait_for_completion() and related routines.
3194 * It may be assumed that this function implies a write memory barrier before
3195 * changing the task state if and only if any tasks are woken up.
3197 void complete(struct completion
*x
)
3199 unsigned long flags
;
3201 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3203 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
3204 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3206 EXPORT_SYMBOL(complete
);
3209 * complete_all: - signals all threads waiting on this completion
3210 * @x: holds the state of this particular completion
3212 * This will wake up all threads waiting on this particular completion event.
3214 * It may be assumed that this function implies a write memory barrier before
3215 * changing the task state if and only if any tasks are woken up.
3217 void complete_all(struct completion
*x
)
3219 unsigned long flags
;
3221 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3222 x
->done
+= UINT_MAX
/2;
3223 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
3224 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3226 EXPORT_SYMBOL(complete_all
);
3228 static inline long __sched
3229 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
3232 DECLARE_WAITQUEUE(wait
, current
);
3234 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
3236 if (signal_pending_state(state
, current
)) {
3237 timeout
= -ERESTARTSYS
;
3240 __set_current_state(state
);
3241 spin_unlock_irq(&x
->wait
.lock
);
3242 timeout
= schedule_timeout(timeout
);
3243 spin_lock_irq(&x
->wait
.lock
);
3244 } while (!x
->done
&& timeout
);
3245 __remove_wait_queue(&x
->wait
, &wait
);
3250 return timeout
?: 1;
3254 wait_for_common(struct completion
*x
, long timeout
, int state
)
3258 spin_lock_irq(&x
->wait
.lock
);
3259 timeout
= do_wait_for_common(x
, timeout
, state
);
3260 spin_unlock_irq(&x
->wait
.lock
);
3265 * wait_for_completion: - waits for completion of a task
3266 * @x: holds the state of this particular completion
3268 * This waits to be signaled for completion of a specific task. It is NOT
3269 * interruptible and there is no timeout.
3271 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
3272 * and interrupt capability. Also see complete().
3274 void __sched
wait_for_completion(struct completion
*x
)
3276 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
3278 EXPORT_SYMBOL(wait_for_completion
);
3281 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
3282 * @x: holds the state of this particular completion
3283 * @timeout: timeout value in jiffies
3285 * This waits for either a completion of a specific task to be signaled or for a
3286 * specified timeout to expire. The timeout is in jiffies. It is not
3289 * The return value is 0 if timed out, and positive (at least 1, or number of
3290 * jiffies left till timeout) if completed.
3292 unsigned long __sched
3293 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
3295 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
3297 EXPORT_SYMBOL(wait_for_completion_timeout
);
3300 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
3301 * @x: holds the state of this particular completion
3303 * This waits for completion of a specific task to be signaled. It is
3306 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3308 int __sched
wait_for_completion_interruptible(struct completion
*x
)
3310 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
3311 if (t
== -ERESTARTSYS
)
3315 EXPORT_SYMBOL(wait_for_completion_interruptible
);
3318 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
3319 * @x: holds the state of this particular completion
3320 * @timeout: timeout value in jiffies
3322 * This waits for either a completion of a specific task to be signaled or for a
3323 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
3325 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3326 * positive (at least 1, or number of jiffies left till timeout) if completed.
3329 wait_for_completion_interruptible_timeout(struct completion
*x
,
3330 unsigned long timeout
)
3332 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
3334 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
3337 * wait_for_completion_killable: - waits for completion of a task (killable)
3338 * @x: holds the state of this particular completion
3340 * This waits to be signaled for completion of a specific task. It can be
3341 * interrupted by a kill signal.
3343 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3345 int __sched
wait_for_completion_killable(struct completion
*x
)
3347 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
3348 if (t
== -ERESTARTSYS
)
3352 EXPORT_SYMBOL(wait_for_completion_killable
);
3355 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
3356 * @x: holds the state of this particular completion
3357 * @timeout: timeout value in jiffies
3359 * This waits for either a completion of a specific task to be
3360 * signaled or for a specified timeout to expire. It can be
3361 * interrupted by a kill signal. The timeout is in jiffies.
3363 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3364 * positive (at least 1, or number of jiffies left till timeout) if completed.
3367 wait_for_completion_killable_timeout(struct completion
*x
,
3368 unsigned long timeout
)
3370 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
3372 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
3375 * try_wait_for_completion - try to decrement a completion without blocking
3376 * @x: completion structure
3378 * Returns: 0 if a decrement cannot be done without blocking
3379 * 1 if a decrement succeeded.
3381 * If a completion is being used as a counting completion,
3382 * attempt to decrement the counter without blocking. This
3383 * enables us to avoid waiting if the resource the completion
3384 * is protecting is not available.
3386 bool try_wait_for_completion(struct completion
*x
)
3388 unsigned long flags
;
3391 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3396 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3399 EXPORT_SYMBOL(try_wait_for_completion
);
3402 * completion_done - Test to see if a completion has any waiters
3403 * @x: completion structure
3405 * Returns: 0 if there are waiters (wait_for_completion() in progress)
3406 * 1 if there are no waiters.
3409 bool completion_done(struct completion
*x
)
3411 unsigned long flags
;
3414 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3417 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3420 EXPORT_SYMBOL(completion_done
);
3423 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
3425 unsigned long flags
;
3428 init_waitqueue_entry(&wait
, current
);
3430 __set_current_state(state
);
3432 spin_lock_irqsave(&q
->lock
, flags
);
3433 __add_wait_queue(q
, &wait
);
3434 spin_unlock(&q
->lock
);
3435 timeout
= schedule_timeout(timeout
);
3436 spin_lock_irq(&q
->lock
);
3437 __remove_wait_queue(q
, &wait
);
3438 spin_unlock_irqrestore(&q
->lock
, flags
);
3443 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
3445 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3447 EXPORT_SYMBOL(interruptible_sleep_on
);
3450 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3452 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
3454 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
3456 void __sched
sleep_on(wait_queue_head_t
*q
)
3458 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3460 EXPORT_SYMBOL(sleep_on
);
3462 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3464 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
3466 EXPORT_SYMBOL(sleep_on_timeout
);
3468 #ifdef CONFIG_RT_MUTEXES
3471 * rt_mutex_setprio - set the current priority of a task
3473 * @prio: prio value (kernel-internal form)
3475 * This function changes the 'effective' priority of a task. It does
3476 * not touch ->normal_prio like __setscheduler().
3478 * Used by the rt_mutex code to implement priority inheritance logic.
3480 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
3482 int oldprio
, on_rq
, running
;
3484 const struct sched_class
*prev_class
;
3486 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
3488 rq
= __task_rq_lock(p
);
3491 * Idle task boosting is a nono in general. There is one
3492 * exception, when PREEMPT_RT and NOHZ is active:
3494 * The idle task calls get_next_timer_interrupt() and holds
3495 * the timer wheel base->lock on the CPU and another CPU wants
3496 * to access the timer (probably to cancel it). We can safely
3497 * ignore the boosting request, as the idle CPU runs this code
3498 * with interrupts disabled and will complete the lock
3499 * protected section without being interrupted. So there is no
3500 * real need to boost.
3502 if (unlikely(p
== rq
->idle
)) {
3503 WARN_ON(p
!= rq
->curr
);
3504 WARN_ON(p
->pi_blocked_on
);
3508 trace_sched_pi_setprio(p
, prio
);
3510 prev_class
= p
->sched_class
;
3512 running
= task_current(rq
, p
);
3514 dequeue_task(rq
, p
, 0);
3516 p
->sched_class
->put_prev_task(rq
, p
);
3519 p
->sched_class
= &rt_sched_class
;
3521 p
->sched_class
= &fair_sched_class
;
3526 p
->sched_class
->set_curr_task(rq
);
3528 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
3530 check_class_changed(rq
, p
, prev_class
, oldprio
);
3532 __task_rq_unlock(rq
);
3535 void set_user_nice(struct task_struct
*p
, long nice
)
3537 int old_prio
, delta
, on_rq
;
3538 unsigned long flags
;
3541 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
3544 * We have to be careful, if called from sys_setpriority(),
3545 * the task might be in the middle of scheduling on another CPU.
3547 rq
= task_rq_lock(p
, &flags
);
3549 * The RT priorities are set via sched_setscheduler(), but we still
3550 * allow the 'normal' nice value to be set - but as expected
3551 * it wont have any effect on scheduling until the task is
3552 * SCHED_FIFO/SCHED_RR:
3554 if (task_has_rt_policy(p
)) {
3555 p
->static_prio
= NICE_TO_PRIO(nice
);
3560 dequeue_task(rq
, p
, 0);
3562 p
->static_prio
= NICE_TO_PRIO(nice
);
3565 p
->prio
= effective_prio(p
);
3566 delta
= p
->prio
- old_prio
;
3569 enqueue_task(rq
, p
, 0);
3571 * If the task increased its priority or is running and
3572 * lowered its priority, then reschedule its CPU:
3574 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3575 resched_task(rq
->curr
);
3578 task_rq_unlock(rq
, p
, &flags
);
3580 EXPORT_SYMBOL(set_user_nice
);
3583 * can_nice - check if a task can reduce its nice value
3587 int can_nice(const struct task_struct
*p
, const int nice
)
3589 /* convert nice value [19,-20] to rlimit style value [1,40] */
3590 int nice_rlim
= 20 - nice
;
3592 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3593 capable(CAP_SYS_NICE
));
3596 #ifdef __ARCH_WANT_SYS_NICE
3599 * sys_nice - change the priority of the current process.
3600 * @increment: priority increment
3602 * sys_setpriority is a more generic, but much slower function that
3603 * does similar things.
3605 SYSCALL_DEFINE1(nice
, int, increment
)
3610 * Setpriority might change our priority at the same moment.
3611 * We don't have to worry. Conceptually one call occurs first
3612 * and we have a single winner.
3614 if (increment
< -40)
3619 nice
= TASK_NICE(current
) + increment
;
3625 if (increment
< 0 && !can_nice(current
, nice
))
3628 retval
= security_task_setnice(current
, nice
);
3632 set_user_nice(current
, nice
);
3639 * task_prio - return the priority value of a given task.
3640 * @p: the task in question.
3642 * This is the priority value as seen by users in /proc.
3643 * RT tasks are offset by -200. Normal tasks are centered
3644 * around 0, value goes from -16 to +15.
3646 int task_prio(const struct task_struct
*p
)
3648 return p
->prio
- MAX_RT_PRIO
;
3652 * task_nice - return the nice value of a given task.
3653 * @p: the task in question.
3655 int task_nice(const struct task_struct
*p
)
3657 return TASK_NICE(p
);
3659 EXPORT_SYMBOL(task_nice
);
3662 * idle_cpu - is a given cpu idle currently?
3663 * @cpu: the processor in question.
3665 int idle_cpu(int cpu
)
3667 struct rq
*rq
= cpu_rq(cpu
);
3669 if (rq
->curr
!= rq
->idle
)
3676 if (!llist_empty(&rq
->wake_list
))
3684 * idle_task - return the idle task for a given cpu.
3685 * @cpu: the processor in question.
3687 struct task_struct
*idle_task(int cpu
)
3689 return cpu_rq(cpu
)->idle
;
3693 * find_process_by_pid - find a process with a matching PID value.
3694 * @pid: the pid in question.
3696 static struct task_struct
*find_process_by_pid(pid_t pid
)
3698 return pid
? find_task_by_vpid(pid
) : current
;
3701 /* Actually do priority change: must hold rq lock. */
3703 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
3706 p
->rt_priority
= prio
;
3707 p
->normal_prio
= normal_prio(p
);
3708 /* we are holding p->pi_lock already */
3709 p
->prio
= rt_mutex_getprio(p
);
3710 if (rt_prio(p
->prio
))
3711 p
->sched_class
= &rt_sched_class
;
3713 p
->sched_class
= &fair_sched_class
;
3718 * check the target process has a UID that matches the current process's
3720 static bool check_same_owner(struct task_struct
*p
)
3722 const struct cred
*cred
= current_cred(), *pcred
;
3726 pcred
= __task_cred(p
);
3727 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3728 uid_eq(cred
->euid
, pcred
->uid
));
3733 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
3734 const struct sched_param
*param
, bool user
)
3736 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
3737 unsigned long flags
;
3738 const struct sched_class
*prev_class
;
3742 /* may grab non-irq protected spin_locks */
3743 BUG_ON(in_interrupt());
3745 /* double check policy once rq lock held */
3747 reset_on_fork
= p
->sched_reset_on_fork
;
3748 policy
= oldpolicy
= p
->policy
;
3750 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
3751 policy
&= ~SCHED_RESET_ON_FORK
;
3753 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3754 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3755 policy
!= SCHED_IDLE
)
3760 * Valid priorities for SCHED_FIFO and SCHED_RR are
3761 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3762 * SCHED_BATCH and SCHED_IDLE is 0.
3764 if (param
->sched_priority
< 0 ||
3765 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3766 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
3768 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
3772 * Allow unprivileged RT tasks to decrease priority:
3774 if (user
&& !capable(CAP_SYS_NICE
)) {
3775 if (rt_policy(policy
)) {
3776 unsigned long rlim_rtprio
=
3777 task_rlimit(p
, RLIMIT_RTPRIO
);
3779 /* can't set/change the rt policy */
3780 if (policy
!= p
->policy
&& !rlim_rtprio
)
3783 /* can't increase priority */
3784 if (param
->sched_priority
> p
->rt_priority
&&
3785 param
->sched_priority
> rlim_rtprio
)
3790 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3791 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3793 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3794 if (!can_nice(p
, TASK_NICE(p
)))
3798 /* can't change other user's priorities */
3799 if (!check_same_owner(p
))
3802 /* Normal users shall not reset the sched_reset_on_fork flag */
3803 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3808 retval
= security_task_setscheduler(p
);
3814 * make sure no PI-waiters arrive (or leave) while we are
3815 * changing the priority of the task:
3817 * To be able to change p->policy safely, the appropriate
3818 * runqueue lock must be held.
3820 rq
= task_rq_lock(p
, &flags
);
3823 * Changing the policy of the stop threads its a very bad idea
3825 if (p
== rq
->stop
) {
3826 task_rq_unlock(rq
, p
, &flags
);
3831 * If not changing anything there's no need to proceed further:
3833 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
3834 param
->sched_priority
== p
->rt_priority
))) {
3835 task_rq_unlock(rq
, p
, &flags
);
3839 #ifdef CONFIG_RT_GROUP_SCHED
3842 * Do not allow realtime tasks into groups that have no runtime
3845 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3846 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3847 !task_group_is_autogroup(task_group(p
))) {
3848 task_rq_unlock(rq
, p
, &flags
);
3854 /* recheck policy now with rq lock held */
3855 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3856 policy
= oldpolicy
= -1;
3857 task_rq_unlock(rq
, p
, &flags
);
3861 running
= task_current(rq
, p
);
3863 dequeue_task(rq
, p
, 0);
3865 p
->sched_class
->put_prev_task(rq
, p
);
3867 p
->sched_reset_on_fork
= reset_on_fork
;
3870 prev_class
= p
->sched_class
;
3871 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
3874 p
->sched_class
->set_curr_task(rq
);
3876 enqueue_task(rq
, p
, 0);
3878 check_class_changed(rq
, p
, prev_class
, oldprio
);
3879 task_rq_unlock(rq
, p
, &flags
);
3881 rt_mutex_adjust_pi(p
);
3887 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3888 * @p: the task in question.
3889 * @policy: new policy.
3890 * @param: structure containing the new RT priority.
3892 * NOTE that the task may be already dead.
3894 int sched_setscheduler(struct task_struct
*p
, int policy
,
3895 const struct sched_param
*param
)
3897 return __sched_setscheduler(p
, policy
, param
, true);
3899 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3902 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3903 * @p: the task in question.
3904 * @policy: new policy.
3905 * @param: structure containing the new RT priority.
3907 * Just like sched_setscheduler, only don't bother checking if the
3908 * current context has permission. For example, this is needed in
3909 * stop_machine(): we create temporary high priority worker threads,
3910 * but our caller might not have that capability.
3912 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3913 const struct sched_param
*param
)
3915 return __sched_setscheduler(p
, policy
, param
, false);
3919 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3921 struct sched_param lparam
;
3922 struct task_struct
*p
;
3925 if (!param
|| pid
< 0)
3927 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3932 p
= find_process_by_pid(pid
);
3934 retval
= sched_setscheduler(p
, policy
, &lparam
);
3941 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3942 * @pid: the pid in question.
3943 * @policy: new policy.
3944 * @param: structure containing the new RT priority.
3946 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3947 struct sched_param __user
*, param
)
3949 /* negative values for policy are not valid */
3953 return do_sched_setscheduler(pid
, policy
, param
);
3957 * sys_sched_setparam - set/change the RT priority of a thread
3958 * @pid: the pid in question.
3959 * @param: structure containing the new RT priority.
3961 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3963 return do_sched_setscheduler(pid
, -1, param
);
3967 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3968 * @pid: the pid in question.
3970 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3972 struct task_struct
*p
;
3980 p
= find_process_by_pid(pid
);
3982 retval
= security_task_getscheduler(p
);
3985 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3992 * sys_sched_getparam - get the RT priority of a thread
3993 * @pid: the pid in question.
3994 * @param: structure containing the RT priority.
3996 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3998 struct sched_param lp
;
3999 struct task_struct
*p
;
4002 if (!param
|| pid
< 0)
4006 p
= find_process_by_pid(pid
);
4011 retval
= security_task_getscheduler(p
);
4015 lp
.sched_priority
= p
->rt_priority
;
4019 * This one might sleep, we cannot do it with a spinlock held ...
4021 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4030 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4032 cpumask_var_t cpus_allowed
, new_mask
;
4033 struct task_struct
*p
;
4039 p
= find_process_by_pid(pid
);
4046 /* Prevent p going away */
4050 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4054 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4056 goto out_free_cpus_allowed
;
4059 if (!check_same_owner(p
) && !ns_capable(task_user_ns(p
), CAP_SYS_NICE
))
4062 retval
= security_task_setscheduler(p
);
4066 cpuset_cpus_allowed(p
, cpus_allowed
);
4067 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4069 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4072 cpuset_cpus_allowed(p
, cpus_allowed
);
4073 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4075 * We must have raced with a concurrent cpuset
4076 * update. Just reset the cpus_allowed to the
4077 * cpuset's cpus_allowed
4079 cpumask_copy(new_mask
, cpus_allowed
);
4084 free_cpumask_var(new_mask
);
4085 out_free_cpus_allowed
:
4086 free_cpumask_var(cpus_allowed
);
4093 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4094 struct cpumask
*new_mask
)
4096 if (len
< cpumask_size())
4097 cpumask_clear(new_mask
);
4098 else if (len
> cpumask_size())
4099 len
= cpumask_size();
4101 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4105 * sys_sched_setaffinity - set the cpu affinity of a process
4106 * @pid: pid of the process
4107 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4108 * @user_mask_ptr: user-space pointer to the new cpu mask
4110 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4111 unsigned long __user
*, user_mask_ptr
)
4113 cpumask_var_t new_mask
;
4116 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4119 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4121 retval
= sched_setaffinity(pid
, new_mask
);
4122 free_cpumask_var(new_mask
);
4126 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4128 struct task_struct
*p
;
4129 unsigned long flags
;
4136 p
= find_process_by_pid(pid
);
4140 retval
= security_task_getscheduler(p
);
4144 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4145 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
4146 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4156 * sys_sched_getaffinity - get the cpu affinity of a process
4157 * @pid: pid of the process
4158 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4159 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4161 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4162 unsigned long __user
*, user_mask_ptr
)
4167 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4169 if (len
& (sizeof(unsigned long)-1))
4172 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4175 ret
= sched_getaffinity(pid
, mask
);
4177 size_t retlen
= min_t(size_t, len
, cpumask_size());
4179 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4184 free_cpumask_var(mask
);
4190 * sys_sched_yield - yield the current processor to other threads.
4192 * This function yields the current CPU to other tasks. If there are no
4193 * other threads running on this CPU then this function will return.
4195 SYSCALL_DEFINE0(sched_yield
)
4197 struct rq
*rq
= this_rq_lock();
4199 schedstat_inc(rq
, yld_count
);
4200 current
->sched_class
->yield_task(rq
);
4203 * Since we are going to call schedule() anyway, there's
4204 * no need to preempt or enable interrupts:
4206 __release(rq
->lock
);
4207 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4208 do_raw_spin_unlock(&rq
->lock
);
4209 sched_preempt_enable_no_resched();
4216 static inline int should_resched(void)
4218 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
4221 static void __cond_resched(void)
4223 add_preempt_count(PREEMPT_ACTIVE
);
4225 sub_preempt_count(PREEMPT_ACTIVE
);
4228 int __sched
_cond_resched(void)
4230 if (should_resched()) {
4236 EXPORT_SYMBOL(_cond_resched
);
4239 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4240 * call schedule, and on return reacquire the lock.
4242 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4243 * operations here to prevent schedule() from being called twice (once via
4244 * spin_unlock(), once by hand).
4246 int __cond_resched_lock(spinlock_t
*lock
)
4248 int resched
= should_resched();
4251 lockdep_assert_held(lock
);
4253 if (spin_needbreak(lock
) || resched
) {
4264 EXPORT_SYMBOL(__cond_resched_lock
);
4266 int __sched
__cond_resched_softirq(void)
4268 BUG_ON(!in_softirq());
4270 if (should_resched()) {
4278 EXPORT_SYMBOL(__cond_resched_softirq
);
4281 * yield - yield the current processor to other threads.
4283 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4285 * The scheduler is at all times free to pick the calling task as the most
4286 * eligible task to run, if removing the yield() call from your code breaks
4287 * it, its already broken.
4289 * Typical broken usage is:
4294 * where one assumes that yield() will let 'the other' process run that will
4295 * make event true. If the current task is a SCHED_FIFO task that will never
4296 * happen. Never use yield() as a progress guarantee!!
4298 * If you want to use yield() to wait for something, use wait_event().
4299 * If you want to use yield() to be 'nice' for others, use cond_resched().
4300 * If you still want to use yield(), do not!
4302 void __sched
yield(void)
4304 set_current_state(TASK_RUNNING
);
4307 EXPORT_SYMBOL(yield
);
4310 * yield_to - yield the current processor to another thread in
4311 * your thread group, or accelerate that thread toward the
4312 * processor it's on.
4314 * @preempt: whether task preemption is allowed or not
4316 * It's the caller's job to ensure that the target task struct
4317 * can't go away on us before we can do any checks.
4319 * Returns true if we indeed boosted the target task.
4321 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
4323 struct task_struct
*curr
= current
;
4324 struct rq
*rq
, *p_rq
;
4325 unsigned long flags
;
4328 local_irq_save(flags
);
4333 double_rq_lock(rq
, p_rq
);
4334 while (task_rq(p
) != p_rq
) {
4335 double_rq_unlock(rq
, p_rq
);
4339 if (!curr
->sched_class
->yield_to_task
)
4342 if (curr
->sched_class
!= p
->sched_class
)
4345 if (task_running(p_rq
, p
) || p
->state
)
4348 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4350 schedstat_inc(rq
, yld_count
);
4352 * Make p's CPU reschedule; pick_next_entity takes care of
4355 if (preempt
&& rq
!= p_rq
)
4356 resched_task(p_rq
->curr
);
4360 double_rq_unlock(rq
, p_rq
);
4361 local_irq_restore(flags
);
4368 EXPORT_SYMBOL_GPL(yield_to
);
4371 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4372 * that process accounting knows that this is a task in IO wait state.
4374 void __sched
io_schedule(void)
4376 struct rq
*rq
= raw_rq();
4378 delayacct_blkio_start();
4379 atomic_inc(&rq
->nr_iowait
);
4380 blk_flush_plug(current
);
4381 current
->in_iowait
= 1;
4383 current
->in_iowait
= 0;
4384 atomic_dec(&rq
->nr_iowait
);
4385 delayacct_blkio_end();
4387 EXPORT_SYMBOL(io_schedule
);
4389 long __sched
io_schedule_timeout(long timeout
)
4391 struct rq
*rq
= raw_rq();
4394 delayacct_blkio_start();
4395 atomic_inc(&rq
->nr_iowait
);
4396 blk_flush_plug(current
);
4397 current
->in_iowait
= 1;
4398 ret
= schedule_timeout(timeout
);
4399 current
->in_iowait
= 0;
4400 atomic_dec(&rq
->nr_iowait
);
4401 delayacct_blkio_end();
4406 * sys_sched_get_priority_max - return maximum RT priority.
4407 * @policy: scheduling class.
4409 * this syscall returns the maximum rt_priority that can be used
4410 * by a given scheduling class.
4412 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4419 ret
= MAX_USER_RT_PRIO
-1;
4431 * sys_sched_get_priority_min - return minimum RT priority.
4432 * @policy: scheduling class.
4434 * this syscall returns the minimum rt_priority that can be used
4435 * by a given scheduling class.
4437 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4455 * sys_sched_rr_get_interval - return the default timeslice of a process.
4456 * @pid: pid of the process.
4457 * @interval: userspace pointer to the timeslice value.
4459 * this syscall writes the default timeslice value of a given process
4460 * into the user-space timespec buffer. A value of '0' means infinity.
4462 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4463 struct timespec __user
*, interval
)
4465 struct task_struct
*p
;
4466 unsigned int time_slice
;
4467 unsigned long flags
;
4477 p
= find_process_by_pid(pid
);
4481 retval
= security_task_getscheduler(p
);
4485 rq
= task_rq_lock(p
, &flags
);
4486 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4487 task_rq_unlock(rq
, p
, &flags
);
4490 jiffies_to_timespec(time_slice
, &t
);
4491 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4499 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4501 void sched_show_task(struct task_struct
*p
)
4503 unsigned long free
= 0;
4507 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4508 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4509 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4510 #if BITS_PER_LONG == 32
4511 if (state
== TASK_RUNNING
)
4512 printk(KERN_CONT
" running ");
4514 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4516 if (state
== TASK_RUNNING
)
4517 printk(KERN_CONT
" running task ");
4519 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4521 #ifdef CONFIG_DEBUG_STACK_USAGE
4522 free
= stack_not_used(p
);
4525 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4527 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4528 task_pid_nr(p
), ppid
,
4529 (unsigned long)task_thread_info(p
)->flags
);
4531 show_stack(p
, NULL
);
4534 void show_state_filter(unsigned long state_filter
)
4536 struct task_struct
*g
, *p
;
4538 #if BITS_PER_LONG == 32
4540 " task PC stack pid father\n");
4543 " task PC stack pid father\n");
4546 do_each_thread(g
, p
) {
4548 * reset the NMI-timeout, listing all files on a slow
4549 * console might take a lot of time:
4551 touch_nmi_watchdog();
4552 if (!state_filter
|| (p
->state
& state_filter
))
4554 } while_each_thread(g
, p
);
4556 touch_all_softlockup_watchdogs();
4558 #ifdef CONFIG_SCHED_DEBUG
4559 sysrq_sched_debug_show();
4563 * Only show locks if all tasks are dumped:
4566 debug_show_all_locks();
4569 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
4571 idle
->sched_class
= &idle_sched_class
;
4575 * init_idle - set up an idle thread for a given CPU
4576 * @idle: task in question
4577 * @cpu: cpu the idle task belongs to
4579 * NOTE: this function does not set the idle thread's NEED_RESCHED
4580 * flag, to make booting more robust.
4582 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
4584 struct rq
*rq
= cpu_rq(cpu
);
4585 unsigned long flags
;
4587 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4590 idle
->state
= TASK_RUNNING
;
4591 idle
->se
.exec_start
= sched_clock();
4593 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4595 * We're having a chicken and egg problem, even though we are
4596 * holding rq->lock, the cpu isn't yet set to this cpu so the
4597 * lockdep check in task_group() will fail.
4599 * Similar case to sched_fork(). / Alternatively we could
4600 * use task_rq_lock() here and obtain the other rq->lock.
4605 __set_task_cpu(idle
, cpu
);
4608 rq
->curr
= rq
->idle
= idle
;
4609 #if defined(CONFIG_SMP)
4612 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4614 /* Set the preempt count _outside_ the spinlocks! */
4615 task_thread_info(idle
)->preempt_count
= 0;
4618 * The idle tasks have their own, simple scheduling class:
4620 idle
->sched_class
= &idle_sched_class
;
4621 ftrace_graph_init_idle_task(idle
, cpu
);
4622 #if defined(CONFIG_SMP)
4623 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4628 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4630 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4631 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4633 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4634 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4638 * This is how migration works:
4640 * 1) we invoke migration_cpu_stop() on the target CPU using
4642 * 2) stopper starts to run (implicitly forcing the migrated thread
4644 * 3) it checks whether the migrated task is still in the wrong runqueue.
4645 * 4) if it's in the wrong runqueue then the migration thread removes
4646 * it and puts it into the right queue.
4647 * 5) stopper completes and stop_one_cpu() returns and the migration
4652 * Change a given task's CPU affinity. Migrate the thread to a
4653 * proper CPU and schedule it away if the CPU it's executing on
4654 * is removed from the allowed bitmask.
4656 * NOTE: the caller must have a valid reference to the task, the
4657 * task must not exit() & deallocate itself prematurely. The
4658 * call is not atomic; no spinlocks may be held.
4660 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4662 unsigned long flags
;
4664 unsigned int dest_cpu
;
4667 rq
= task_rq_lock(p
, &flags
);
4669 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4672 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4677 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
)) {
4682 do_set_cpus_allowed(p
, new_mask
);
4684 /* Can the task run on the task's current CPU? If so, we're done */
4685 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4688 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4690 struct migration_arg arg
= { p
, dest_cpu
};
4691 /* Need help from migration thread: drop lock and wait. */
4692 task_rq_unlock(rq
, p
, &flags
);
4693 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4694 tlb_migrate_finish(p
->mm
);
4698 task_rq_unlock(rq
, p
, &flags
);
4702 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4705 * Move (not current) task off this cpu, onto dest cpu. We're doing
4706 * this because either it can't run here any more (set_cpus_allowed()
4707 * away from this CPU, or CPU going down), or because we're
4708 * attempting to rebalance this task on exec (sched_exec).
4710 * So we race with normal scheduler movements, but that's OK, as long
4711 * as the task is no longer on this CPU.
4713 * Returns non-zero if task was successfully migrated.
4715 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4717 struct rq
*rq_dest
, *rq_src
;
4720 if (unlikely(!cpu_active(dest_cpu
)))
4723 rq_src
= cpu_rq(src_cpu
);
4724 rq_dest
= cpu_rq(dest_cpu
);
4726 raw_spin_lock(&p
->pi_lock
);
4727 double_rq_lock(rq_src
, rq_dest
);
4728 /* Already moved. */
4729 if (task_cpu(p
) != src_cpu
)
4731 /* Affinity changed (again). */
4732 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4736 * If we're not on a rq, the next wake-up will ensure we're
4740 dequeue_task(rq_src
, p
, 0);
4741 set_task_cpu(p
, dest_cpu
);
4742 enqueue_task(rq_dest
, p
, 0);
4743 check_preempt_curr(rq_dest
, p
, 0);
4748 double_rq_unlock(rq_src
, rq_dest
);
4749 raw_spin_unlock(&p
->pi_lock
);
4754 * migration_cpu_stop - this will be executed by a highprio stopper thread
4755 * and performs thread migration by bumping thread off CPU then
4756 * 'pushing' onto another runqueue.
4758 static int migration_cpu_stop(void *data
)
4760 struct migration_arg
*arg
= data
;
4763 * The original target cpu might have gone down and we might
4764 * be on another cpu but it doesn't matter.
4766 local_irq_disable();
4767 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4772 #ifdef CONFIG_HOTPLUG_CPU
4775 * Ensures that the idle task is using init_mm right before its cpu goes
4778 void idle_task_exit(void)
4780 struct mm_struct
*mm
= current
->active_mm
;
4782 BUG_ON(cpu_online(smp_processor_id()));
4785 switch_mm(mm
, &init_mm
, current
);
4790 * Since this CPU is going 'away' for a while, fold any nr_active delta
4791 * we might have. Assumes we're called after migrate_tasks() so that the
4792 * nr_active count is stable.
4794 * Also see the comment "Global load-average calculations".
4796 static void calc_load_migrate(struct rq
*rq
)
4798 long delta
= calc_load_fold_active(rq
);
4800 atomic_long_add(delta
, &calc_load_tasks
);
4804 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4805 * try_to_wake_up()->select_task_rq().
4807 * Called with rq->lock held even though we'er in stop_machine() and
4808 * there's no concurrency possible, we hold the required locks anyway
4809 * because of lock validation efforts.
4811 static void migrate_tasks(unsigned int dead_cpu
)
4813 struct rq
*rq
= cpu_rq(dead_cpu
);
4814 struct task_struct
*next
, *stop
= rq
->stop
;
4818 * Fudge the rq selection such that the below task selection loop
4819 * doesn't get stuck on the currently eligible stop task.
4821 * We're currently inside stop_machine() and the rq is either stuck
4822 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4823 * either way we should never end up calling schedule() until we're
4830 * There's this thread running, bail when that's the only
4833 if (rq
->nr_running
== 1)
4836 next
= pick_next_task(rq
);
4838 next
->sched_class
->put_prev_task(rq
, next
);
4840 /* Find suitable destination for @next, with force if needed. */
4841 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
4842 raw_spin_unlock(&rq
->lock
);
4844 __migrate_task(next
, dead_cpu
, dest_cpu
);
4846 raw_spin_lock(&rq
->lock
);
4852 #endif /* CONFIG_HOTPLUG_CPU */
4854 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4856 static struct ctl_table sd_ctl_dir
[] = {
4858 .procname
= "sched_domain",
4864 static struct ctl_table sd_ctl_root
[] = {
4866 .procname
= "kernel",
4868 .child
= sd_ctl_dir
,
4873 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
4875 struct ctl_table
*entry
=
4876 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
4881 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
4883 struct ctl_table
*entry
;
4886 * In the intermediate directories, both the child directory and
4887 * procname are dynamically allocated and could fail but the mode
4888 * will always be set. In the lowest directory the names are
4889 * static strings and all have proc handlers.
4891 for (entry
= *tablep
; entry
->mode
; entry
++) {
4893 sd_free_ctl_entry(&entry
->child
);
4894 if (entry
->proc_handler
== NULL
)
4895 kfree(entry
->procname
);
4902 static int min_load_idx
= 0;
4903 static int max_load_idx
= CPU_LOAD_IDX_MAX
;
4906 set_table_entry(struct ctl_table
*entry
,
4907 const char *procname
, void *data
, int maxlen
,
4908 umode_t mode
, proc_handler
*proc_handler
,
4911 entry
->procname
= procname
;
4913 entry
->maxlen
= maxlen
;
4915 entry
->proc_handler
= proc_handler
;
4918 entry
->extra1
= &min_load_idx
;
4919 entry
->extra2
= &max_load_idx
;
4923 static struct ctl_table
*
4924 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
4926 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
4931 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
4932 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4933 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
4934 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4935 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
4936 sizeof(int), 0644, proc_dointvec_minmax
, true);
4937 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
4938 sizeof(int), 0644, proc_dointvec_minmax
, true);
4939 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
4940 sizeof(int), 0644, proc_dointvec_minmax
, true);
4941 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
4942 sizeof(int), 0644, proc_dointvec_minmax
, true);
4943 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
4944 sizeof(int), 0644, proc_dointvec_minmax
, true);
4945 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
4946 sizeof(int), 0644, proc_dointvec_minmax
, false);
4947 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
4948 sizeof(int), 0644, proc_dointvec_minmax
, false);
4949 set_table_entry(&table
[9], "cache_nice_tries",
4950 &sd
->cache_nice_tries
,
4951 sizeof(int), 0644, proc_dointvec_minmax
, false);
4952 set_table_entry(&table
[10], "flags", &sd
->flags
,
4953 sizeof(int), 0644, proc_dointvec_minmax
, false);
4954 set_table_entry(&table
[11], "name", sd
->name
,
4955 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
4956 /* &table[12] is terminator */
4961 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
4963 struct ctl_table
*entry
, *table
;
4964 struct sched_domain
*sd
;
4965 int domain_num
= 0, i
;
4968 for_each_domain(cpu
, sd
)
4970 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
4975 for_each_domain(cpu
, sd
) {
4976 snprintf(buf
, 32, "domain%d", i
);
4977 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4979 entry
->child
= sd_alloc_ctl_domain_table(sd
);
4986 static struct ctl_table_header
*sd_sysctl_header
;
4987 static void register_sched_domain_sysctl(void)
4989 int i
, cpu_num
= num_possible_cpus();
4990 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
4993 WARN_ON(sd_ctl_dir
[0].child
);
4994 sd_ctl_dir
[0].child
= entry
;
4999 for_each_possible_cpu(i
) {
5000 snprintf(buf
, 32, "cpu%d", i
);
5001 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5003 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5007 WARN_ON(sd_sysctl_header
);
5008 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5011 /* may be called multiple times per register */
5012 static void unregister_sched_domain_sysctl(void)
5014 if (sd_sysctl_header
)
5015 unregister_sysctl_table(sd_sysctl_header
);
5016 sd_sysctl_header
= NULL
;
5017 if (sd_ctl_dir
[0].child
)
5018 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5021 static void register_sched_domain_sysctl(void)
5024 static void unregister_sched_domain_sysctl(void)
5029 static void set_rq_online(struct rq
*rq
)
5032 const struct sched_class
*class;
5034 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5037 for_each_class(class) {
5038 if (class->rq_online
)
5039 class->rq_online(rq
);
5044 static void set_rq_offline(struct rq
*rq
)
5047 const struct sched_class
*class;
5049 for_each_class(class) {
5050 if (class->rq_offline
)
5051 class->rq_offline(rq
);
5054 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5060 * migration_call - callback that gets triggered when a CPU is added.
5061 * Here we can start up the necessary migration thread for the new CPU.
5063 static int __cpuinit
5064 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5066 int cpu
= (long)hcpu
;
5067 unsigned long flags
;
5068 struct rq
*rq
= cpu_rq(cpu
);
5070 switch (action
& ~CPU_TASKS_FROZEN
) {
5072 case CPU_UP_PREPARE
:
5073 rq
->calc_load_update
= calc_load_update
;
5077 /* Update our root-domain */
5078 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5080 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5084 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5087 #ifdef CONFIG_HOTPLUG_CPU
5089 sched_ttwu_pending();
5090 /* Update our root-domain */
5091 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5093 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5097 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5098 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5102 calc_load_migrate(rq
);
5107 update_max_interval();
5113 * Register at high priority so that task migration (migrate_all_tasks)
5114 * happens before everything else. This has to be lower priority than
5115 * the notifier in the perf_event subsystem, though.
5117 static struct notifier_block __cpuinitdata migration_notifier
= {
5118 .notifier_call
= migration_call
,
5119 .priority
= CPU_PRI_MIGRATION
,
5122 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
5123 unsigned long action
, void *hcpu
)
5125 switch (action
& ~CPU_TASKS_FROZEN
) {
5127 case CPU_DOWN_FAILED
:
5128 set_cpu_active((long)hcpu
, true);
5135 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
5136 unsigned long action
, void *hcpu
)
5138 switch (action
& ~CPU_TASKS_FROZEN
) {
5139 case CPU_DOWN_PREPARE
:
5140 set_cpu_active((long)hcpu
, false);
5147 static int __init
migration_init(void)
5149 void *cpu
= (void *)(long)smp_processor_id();
5152 /* Initialize migration for the boot CPU */
5153 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5154 BUG_ON(err
== NOTIFY_BAD
);
5155 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5156 register_cpu_notifier(&migration_notifier
);
5158 /* Register cpu active notifiers */
5159 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5160 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5164 early_initcall(migration_init
);
5169 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5171 #ifdef CONFIG_SCHED_DEBUG
5173 static __read_mostly
int sched_debug_enabled
;
5175 static int __init
sched_debug_setup(char *str
)
5177 sched_debug_enabled
= 1;
5181 early_param("sched_debug", sched_debug_setup
);
5183 static inline bool sched_debug(void)
5185 return sched_debug_enabled
;
5188 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5189 struct cpumask
*groupmask
)
5191 struct sched_group
*group
= sd
->groups
;
5194 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5195 cpumask_clear(groupmask
);
5197 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5199 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5200 printk("does not load-balance\n");
5202 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5207 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5209 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5210 printk(KERN_ERR
"ERROR: domain->span does not contain "
5213 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5214 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5218 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5222 printk(KERN_ERR
"ERROR: group is NULL\n");
5227 * Even though we initialize ->power to something semi-sane,
5228 * we leave power_orig unset. This allows us to detect if
5229 * domain iteration is still funny without causing /0 traps.
5231 if (!group
->sgp
->power_orig
) {
5232 printk(KERN_CONT
"\n");
5233 printk(KERN_ERR
"ERROR: domain->cpu_power not "
5238 if (!cpumask_weight(sched_group_cpus(group
))) {
5239 printk(KERN_CONT
"\n");
5240 printk(KERN_ERR
"ERROR: empty group\n");
5244 if (!(sd
->flags
& SD_OVERLAP
) &&
5245 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5246 printk(KERN_CONT
"\n");
5247 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5251 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5253 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
5255 printk(KERN_CONT
" %s", str
);
5256 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
5257 printk(KERN_CONT
" (cpu_power = %d)",
5261 group
= group
->next
;
5262 } while (group
!= sd
->groups
);
5263 printk(KERN_CONT
"\n");
5265 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5266 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5269 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5270 printk(KERN_ERR
"ERROR: parent span is not a superset "
5271 "of domain->span\n");
5275 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5279 if (!sched_debug_enabled
)
5283 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5287 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5290 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5298 #else /* !CONFIG_SCHED_DEBUG */
5299 # define sched_domain_debug(sd, cpu) do { } while (0)
5300 static inline bool sched_debug(void)
5304 #endif /* CONFIG_SCHED_DEBUG */
5306 static int sd_degenerate(struct sched_domain
*sd
)
5308 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5311 /* Following flags need at least 2 groups */
5312 if (sd
->flags
& (SD_LOAD_BALANCE
|
5313 SD_BALANCE_NEWIDLE
|
5317 SD_SHARE_PKG_RESOURCES
)) {
5318 if (sd
->groups
!= sd
->groups
->next
)
5322 /* Following flags don't use groups */
5323 if (sd
->flags
& (SD_WAKE_AFFINE
))
5330 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5332 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5334 if (sd_degenerate(parent
))
5337 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5340 /* Flags needing groups don't count if only 1 group in parent */
5341 if (parent
->groups
== parent
->groups
->next
) {
5342 pflags
&= ~(SD_LOAD_BALANCE
|
5343 SD_BALANCE_NEWIDLE
|
5347 SD_SHARE_PKG_RESOURCES
);
5348 if (nr_node_ids
== 1)
5349 pflags
&= ~SD_SERIALIZE
;
5351 if (~cflags
& pflags
)
5357 static void free_rootdomain(struct rcu_head
*rcu
)
5359 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5361 cpupri_cleanup(&rd
->cpupri
);
5362 free_cpumask_var(rd
->rto_mask
);
5363 free_cpumask_var(rd
->online
);
5364 free_cpumask_var(rd
->span
);
5368 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5370 struct root_domain
*old_rd
= NULL
;
5371 unsigned long flags
;
5373 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5378 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5381 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5384 * If we dont want to free the old_rt yet then
5385 * set old_rd to NULL to skip the freeing later
5388 if (!atomic_dec_and_test(&old_rd
->refcount
))
5392 atomic_inc(&rd
->refcount
);
5395 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5396 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5399 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5402 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5405 static int init_rootdomain(struct root_domain
*rd
)
5407 memset(rd
, 0, sizeof(*rd
));
5409 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5411 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5413 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5416 if (cpupri_init(&rd
->cpupri
) != 0)
5421 free_cpumask_var(rd
->rto_mask
);
5423 free_cpumask_var(rd
->online
);
5425 free_cpumask_var(rd
->span
);
5431 * By default the system creates a single root-domain with all cpus as
5432 * members (mimicking the global state we have today).
5434 struct root_domain def_root_domain
;
5436 static void init_defrootdomain(void)
5438 init_rootdomain(&def_root_domain
);
5440 atomic_set(&def_root_domain
.refcount
, 1);
5443 static struct root_domain
*alloc_rootdomain(void)
5445 struct root_domain
*rd
;
5447 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5451 if (init_rootdomain(rd
) != 0) {
5459 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
5461 struct sched_group
*tmp
, *first
;
5470 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
5475 } while (sg
!= first
);
5478 static void free_sched_domain(struct rcu_head
*rcu
)
5480 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5483 * If its an overlapping domain it has private groups, iterate and
5486 if (sd
->flags
& SD_OVERLAP
) {
5487 free_sched_groups(sd
->groups
, 1);
5488 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5489 kfree(sd
->groups
->sgp
);
5495 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5497 call_rcu(&sd
->rcu
, free_sched_domain
);
5500 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5502 for (; sd
; sd
= sd
->parent
)
5503 destroy_sched_domain(sd
, cpu
);
5507 * Keep a special pointer to the highest sched_domain that has
5508 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5509 * allows us to avoid some pointer chasing select_idle_sibling().
5511 * Also keep a unique ID per domain (we use the first cpu number in
5512 * the cpumask of the domain), this allows us to quickly tell if
5513 * two cpus are in the same cache domain, see cpus_share_cache().
5515 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5516 DEFINE_PER_CPU(int, sd_llc_id
);
5518 static void update_top_cache_domain(int cpu
)
5520 struct sched_domain
*sd
;
5523 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5525 id
= cpumask_first(sched_domain_span(sd
));
5527 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5528 per_cpu(sd_llc_id
, cpu
) = id
;
5532 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5533 * hold the hotplug lock.
5536 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5538 struct rq
*rq
= cpu_rq(cpu
);
5539 struct sched_domain
*tmp
;
5541 /* Remove the sched domains which do not contribute to scheduling. */
5542 for (tmp
= sd
; tmp
; ) {
5543 struct sched_domain
*parent
= tmp
->parent
;
5547 if (sd_parent_degenerate(tmp
, parent
)) {
5548 tmp
->parent
= parent
->parent
;
5550 parent
->parent
->child
= tmp
;
5551 destroy_sched_domain(parent
, cpu
);
5556 if (sd
&& sd_degenerate(sd
)) {
5559 destroy_sched_domain(tmp
, cpu
);
5564 sched_domain_debug(sd
, cpu
);
5566 rq_attach_root(rq
, rd
);
5568 rcu_assign_pointer(rq
->sd
, sd
);
5569 destroy_sched_domains(tmp
, cpu
);
5571 update_top_cache_domain(cpu
);
5574 /* cpus with isolated domains */
5575 static cpumask_var_t cpu_isolated_map
;
5577 /* Setup the mask of cpus configured for isolated domains */
5578 static int __init
isolated_cpu_setup(char *str
)
5580 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5581 cpulist_parse(str
, cpu_isolated_map
);
5585 __setup("isolcpus=", isolated_cpu_setup
);
5587 static const struct cpumask
*cpu_cpu_mask(int cpu
)
5589 return cpumask_of_node(cpu_to_node(cpu
));
5593 struct sched_domain
**__percpu sd
;
5594 struct sched_group
**__percpu sg
;
5595 struct sched_group_power
**__percpu sgp
;
5599 struct sched_domain
** __percpu sd
;
5600 struct root_domain
*rd
;
5610 struct sched_domain_topology_level
;
5612 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
5613 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
5615 #define SDTL_OVERLAP 0x01
5617 struct sched_domain_topology_level
{
5618 sched_domain_init_f init
;
5619 sched_domain_mask_f mask
;
5622 struct sd_data data
;
5626 * Build an iteration mask that can exclude certain CPUs from the upwards
5629 * Asymmetric node setups can result in situations where the domain tree is of
5630 * unequal depth, make sure to skip domains that already cover the entire
5633 * In that case build_sched_domains() will have terminated the iteration early
5634 * and our sibling sd spans will be empty. Domains should always include the
5635 * cpu they're built on, so check that.
5638 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5640 const struct cpumask
*span
= sched_domain_span(sd
);
5641 struct sd_data
*sdd
= sd
->private;
5642 struct sched_domain
*sibling
;
5645 for_each_cpu(i
, span
) {
5646 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5647 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5650 cpumask_set_cpu(i
, sched_group_mask(sg
));
5655 * Return the canonical balance cpu for this group, this is the first cpu
5656 * of this group that's also in the iteration mask.
5658 int group_balance_cpu(struct sched_group
*sg
)
5660 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5664 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5666 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5667 const struct cpumask
*span
= sched_domain_span(sd
);
5668 struct cpumask
*covered
= sched_domains_tmpmask
;
5669 struct sd_data
*sdd
= sd
->private;
5670 struct sched_domain
*child
;
5673 cpumask_clear(covered
);
5675 for_each_cpu(i
, span
) {
5676 struct cpumask
*sg_span
;
5678 if (cpumask_test_cpu(i
, covered
))
5681 child
= *per_cpu_ptr(sdd
->sd
, i
);
5683 /* See the comment near build_group_mask(). */
5684 if (!cpumask_test_cpu(i
, sched_domain_span(child
)))
5687 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5688 GFP_KERNEL
, cpu_to_node(cpu
));
5693 sg_span
= sched_group_cpus(sg
);
5695 child
= child
->child
;
5696 cpumask_copy(sg_span
, sched_domain_span(child
));
5698 cpumask_set_cpu(i
, sg_span
);
5700 cpumask_or(covered
, covered
, sg_span
);
5702 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, i
);
5703 if (atomic_inc_return(&sg
->sgp
->ref
) == 1)
5704 build_group_mask(sd
, sg
);
5707 * Initialize sgp->power such that even if we mess up the
5708 * domains and no possible iteration will get us here, we won't
5711 sg
->sgp
->power
= SCHED_POWER_SCALE
* cpumask_weight(sg_span
);
5714 * Make sure the first group of this domain contains the
5715 * canonical balance cpu. Otherwise the sched_domain iteration
5716 * breaks. See update_sg_lb_stats().
5718 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5719 group_balance_cpu(sg
) == cpu
)
5729 sd
->groups
= groups
;
5734 free_sched_groups(first
, 0);
5739 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5741 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5742 struct sched_domain
*child
= sd
->child
;
5745 cpu
= cpumask_first(sched_domain_span(child
));
5748 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5749 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
5750 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
5757 * build_sched_groups will build a circular linked list of the groups
5758 * covered by the given span, and will set each group's ->cpumask correctly,
5759 * and ->cpu_power to 0.
5761 * Assumes the sched_domain tree is fully constructed
5764 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5766 struct sched_group
*first
= NULL
, *last
= NULL
;
5767 struct sd_data
*sdd
= sd
->private;
5768 const struct cpumask
*span
= sched_domain_span(sd
);
5769 struct cpumask
*covered
;
5772 get_group(cpu
, sdd
, &sd
->groups
);
5773 atomic_inc(&sd
->groups
->ref
);
5775 if (cpu
!= cpumask_first(sched_domain_span(sd
)))
5778 lockdep_assert_held(&sched_domains_mutex
);
5779 covered
= sched_domains_tmpmask
;
5781 cpumask_clear(covered
);
5783 for_each_cpu(i
, span
) {
5784 struct sched_group
*sg
;
5785 int group
= get_group(i
, sdd
, &sg
);
5788 if (cpumask_test_cpu(i
, covered
))
5791 cpumask_clear(sched_group_cpus(sg
));
5793 cpumask_setall(sched_group_mask(sg
));
5795 for_each_cpu(j
, span
) {
5796 if (get_group(j
, sdd
, NULL
) != group
)
5799 cpumask_set_cpu(j
, covered
);
5800 cpumask_set_cpu(j
, sched_group_cpus(sg
));
5815 * Initialize sched groups cpu_power.
5817 * cpu_power indicates the capacity of sched group, which is used while
5818 * distributing the load between different sched groups in a sched domain.
5819 * Typically cpu_power for all the groups in a sched domain will be same unless
5820 * there are asymmetries in the topology. If there are asymmetries, group
5821 * having more cpu_power will pickup more load compared to the group having
5824 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
5826 struct sched_group
*sg
= sd
->groups
;
5828 WARN_ON(!sd
|| !sg
);
5831 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
5833 } while (sg
!= sd
->groups
);
5835 if (cpu
!= group_balance_cpu(sg
))
5838 update_group_power(sd
, cpu
);
5839 atomic_set(&sg
->sgp
->nr_busy_cpus
, sg
->group_weight
);
5842 int __weak
arch_sd_sibling_asym_packing(void)
5844 return 0*SD_ASYM_PACKING
;
5848 * Initializers for schedule domains
5849 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5852 #ifdef CONFIG_SCHED_DEBUG
5853 # define SD_INIT_NAME(sd, type) sd->name = #type
5855 # define SD_INIT_NAME(sd, type) do { } while (0)
5858 #define SD_INIT_FUNC(type) \
5859 static noinline struct sched_domain * \
5860 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
5862 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
5863 *sd = SD_##type##_INIT; \
5864 SD_INIT_NAME(sd, type); \
5865 sd->private = &tl->data; \
5870 #ifdef CONFIG_SCHED_SMT
5871 SD_INIT_FUNC(SIBLING
)
5873 #ifdef CONFIG_SCHED_MC
5876 #ifdef CONFIG_SCHED_BOOK
5880 static int default_relax_domain_level
= -1;
5881 int sched_domain_level_max
;
5883 static int __init
setup_relax_domain_level(char *str
)
5885 if (kstrtoint(str
, 0, &default_relax_domain_level
))
5886 pr_warn("Unable to set relax_domain_level\n");
5890 __setup("relax_domain_level=", setup_relax_domain_level
);
5892 static void set_domain_attribute(struct sched_domain
*sd
,
5893 struct sched_domain_attr
*attr
)
5897 if (!attr
|| attr
->relax_domain_level
< 0) {
5898 if (default_relax_domain_level
< 0)
5901 request
= default_relax_domain_level
;
5903 request
= attr
->relax_domain_level
;
5904 if (request
< sd
->level
) {
5905 /* turn off idle balance on this domain */
5906 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5908 /* turn on idle balance on this domain */
5909 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5913 static void __sdt_free(const struct cpumask
*cpu_map
);
5914 static int __sdt_alloc(const struct cpumask
*cpu_map
);
5916 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
5917 const struct cpumask
*cpu_map
)
5921 if (!atomic_read(&d
->rd
->refcount
))
5922 free_rootdomain(&d
->rd
->rcu
); /* fall through */
5924 free_percpu(d
->sd
); /* fall through */
5926 __sdt_free(cpu_map
); /* fall through */
5932 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
5933 const struct cpumask
*cpu_map
)
5935 memset(d
, 0, sizeof(*d
));
5937 if (__sdt_alloc(cpu_map
))
5938 return sa_sd_storage
;
5939 d
->sd
= alloc_percpu(struct sched_domain
*);
5941 return sa_sd_storage
;
5942 d
->rd
= alloc_rootdomain();
5945 return sa_rootdomain
;
5949 * NULL the sd_data elements we've used to build the sched_domain and
5950 * sched_group structure so that the subsequent __free_domain_allocs()
5951 * will not free the data we're using.
5953 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
5955 struct sd_data
*sdd
= sd
->private;
5957 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
5958 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
5960 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
5961 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
5963 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
5964 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
5967 #ifdef CONFIG_SCHED_SMT
5968 static const struct cpumask
*cpu_smt_mask(int cpu
)
5970 return topology_thread_cpumask(cpu
);
5975 * Topology list, bottom-up.
5977 static struct sched_domain_topology_level default_topology
[] = {
5978 #ifdef CONFIG_SCHED_SMT
5979 { sd_init_SIBLING
, cpu_smt_mask
, },
5981 #ifdef CONFIG_SCHED_MC
5982 { sd_init_MC
, cpu_coregroup_mask
, },
5984 #ifdef CONFIG_SCHED_BOOK
5985 { sd_init_BOOK
, cpu_book_mask
, },
5987 { sd_init_CPU
, cpu_cpu_mask
, },
5991 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
5995 static int sched_domains_numa_levels
;
5996 static int *sched_domains_numa_distance
;
5997 static struct cpumask
***sched_domains_numa_masks
;
5998 static int sched_domains_curr_level
;
6000 static inline int sd_local_flags(int level
)
6002 if (sched_domains_numa_distance
[level
] > RECLAIM_DISTANCE
)
6005 return SD_BALANCE_EXEC
| SD_BALANCE_FORK
| SD_WAKE_AFFINE
;
6008 static struct sched_domain
*
6009 sd_numa_init(struct sched_domain_topology_level
*tl
, int cpu
)
6011 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
6012 int level
= tl
->numa_level
;
6013 int sd_weight
= cpumask_weight(
6014 sched_domains_numa_masks
[level
][cpu_to_node(cpu
)]);
6016 *sd
= (struct sched_domain
){
6017 .min_interval
= sd_weight
,
6018 .max_interval
= 2*sd_weight
,
6020 .imbalance_pct
= 125,
6021 .cache_nice_tries
= 2,
6028 .flags
= 1*SD_LOAD_BALANCE
6029 | 1*SD_BALANCE_NEWIDLE
6034 | 0*SD_SHARE_CPUPOWER
6035 | 0*SD_SHARE_PKG_RESOURCES
6037 | 0*SD_PREFER_SIBLING
6038 | sd_local_flags(level
)
6040 .last_balance
= jiffies
,
6041 .balance_interval
= sd_weight
,
6043 SD_INIT_NAME(sd
, NUMA
);
6044 sd
->private = &tl
->data
;
6047 * Ugly hack to pass state to sd_numa_mask()...
6049 sched_domains_curr_level
= tl
->numa_level
;
6054 static const struct cpumask
*sd_numa_mask(int cpu
)
6056 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6059 static void sched_numa_warn(const char *str
)
6061 static int done
= false;
6069 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6071 for (i
= 0; i
< nr_node_ids
; i
++) {
6072 printk(KERN_WARNING
" ");
6073 for (j
= 0; j
< nr_node_ids
; j
++)
6074 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6075 printk(KERN_CONT
"\n");
6077 printk(KERN_WARNING
"\n");
6080 static bool find_numa_distance(int distance
)
6084 if (distance
== node_distance(0, 0))
6087 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6088 if (sched_domains_numa_distance
[i
] == distance
)
6095 static void sched_init_numa(void)
6097 int next_distance
, curr_distance
= node_distance(0, 0);
6098 struct sched_domain_topology_level
*tl
;
6102 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6103 if (!sched_domains_numa_distance
)
6107 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6108 * unique distances in the node_distance() table.
6110 * Assumes node_distance(0,j) includes all distances in
6111 * node_distance(i,j) in order to avoid cubic time.
6113 next_distance
= curr_distance
;
6114 for (i
= 0; i
< nr_node_ids
; i
++) {
6115 for (j
= 0; j
< nr_node_ids
; j
++) {
6116 for (k
= 0; k
< nr_node_ids
; k
++) {
6117 int distance
= node_distance(i
, k
);
6119 if (distance
> curr_distance
&&
6120 (distance
< next_distance
||
6121 next_distance
== curr_distance
))
6122 next_distance
= distance
;
6125 * While not a strong assumption it would be nice to know
6126 * about cases where if node A is connected to B, B is not
6127 * equally connected to A.
6129 if (sched_debug() && node_distance(k
, i
) != distance
)
6130 sched_numa_warn("Node-distance not symmetric");
6132 if (sched_debug() && i
&& !find_numa_distance(distance
))
6133 sched_numa_warn("Node-0 not representative");
6135 if (next_distance
!= curr_distance
) {
6136 sched_domains_numa_distance
[level
++] = next_distance
;
6137 sched_domains_numa_levels
= level
;
6138 curr_distance
= next_distance
;
6143 * In case of sched_debug() we verify the above assumption.
6149 * 'level' contains the number of unique distances, excluding the
6150 * identity distance node_distance(i,i).
6152 * The sched_domains_nume_distance[] array includes the actual distance
6157 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6158 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6159 * the array will contain less then 'level' members. This could be
6160 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6161 * in other functions.
6163 * We reset it to 'level' at the end of this function.
6165 sched_domains_numa_levels
= 0;
6167 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6168 if (!sched_domains_numa_masks
)
6172 * Now for each level, construct a mask per node which contains all
6173 * cpus of nodes that are that many hops away from us.
6175 for (i
= 0; i
< level
; i
++) {
6176 sched_domains_numa_masks
[i
] =
6177 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6178 if (!sched_domains_numa_masks
[i
])
6181 for (j
= 0; j
< nr_node_ids
; j
++) {
6182 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6186 sched_domains_numa_masks
[i
][j
] = mask
;
6188 for (k
= 0; k
< nr_node_ids
; k
++) {
6189 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6192 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6197 tl
= kzalloc((ARRAY_SIZE(default_topology
) + level
) *
6198 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6203 * Copy the default topology bits..
6205 for (i
= 0; default_topology
[i
].init
; i
++)
6206 tl
[i
] = default_topology
[i
];
6209 * .. and append 'j' levels of NUMA goodness.
6211 for (j
= 0; j
< level
; i
++, j
++) {
6212 tl
[i
] = (struct sched_domain_topology_level
){
6213 .init
= sd_numa_init
,
6214 .mask
= sd_numa_mask
,
6215 .flags
= SDTL_OVERLAP
,
6220 sched_domain_topology
= tl
;
6222 sched_domains_numa_levels
= level
;
6225 static void sched_domains_numa_masks_set(int cpu
)
6228 int node
= cpu_to_node(cpu
);
6230 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6231 for (j
= 0; j
< nr_node_ids
; j
++) {
6232 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6233 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6238 static void sched_domains_numa_masks_clear(int cpu
)
6241 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6242 for (j
= 0; j
< nr_node_ids
; j
++)
6243 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6248 * Update sched_domains_numa_masks[level][node] array when new cpus
6251 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6252 unsigned long action
,
6255 int cpu
= (long)hcpu
;
6257 switch (action
& ~CPU_TASKS_FROZEN
) {
6259 sched_domains_numa_masks_set(cpu
);
6263 sched_domains_numa_masks_clear(cpu
);
6273 static inline void sched_init_numa(void)
6277 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6278 unsigned long action
,
6283 #endif /* CONFIG_NUMA */
6285 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6287 struct sched_domain_topology_level
*tl
;
6290 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6291 struct sd_data
*sdd
= &tl
->data
;
6293 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6297 sdd
->sg
= alloc_percpu(struct sched_group
*);
6301 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
6305 for_each_cpu(j
, cpu_map
) {
6306 struct sched_domain
*sd
;
6307 struct sched_group
*sg
;
6308 struct sched_group_power
*sgp
;
6310 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6311 GFP_KERNEL
, cpu_to_node(j
));
6315 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6317 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6318 GFP_KERNEL
, cpu_to_node(j
));
6324 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6326 sgp
= kzalloc_node(sizeof(struct sched_group_power
) + cpumask_size(),
6327 GFP_KERNEL
, cpu_to_node(j
));
6331 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
6338 static void __sdt_free(const struct cpumask
*cpu_map
)
6340 struct sched_domain_topology_level
*tl
;
6343 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6344 struct sd_data
*sdd
= &tl
->data
;
6346 for_each_cpu(j
, cpu_map
) {
6347 struct sched_domain
*sd
;
6350 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6351 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6352 free_sched_groups(sd
->groups
, 0);
6353 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6357 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6359 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
6361 free_percpu(sdd
->sd
);
6363 free_percpu(sdd
->sg
);
6365 free_percpu(sdd
->sgp
);
6370 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6371 struct s_data
*d
, const struct cpumask
*cpu_map
,
6372 struct sched_domain_attr
*attr
, struct sched_domain
*child
,
6375 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
6379 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6381 sd
->level
= child
->level
+ 1;
6382 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6386 set_domain_attribute(sd
, attr
);
6392 * Build sched domains for a given set of cpus and attach the sched domains
6393 * to the individual cpus
6395 static int build_sched_domains(const struct cpumask
*cpu_map
,
6396 struct sched_domain_attr
*attr
)
6398 enum s_alloc alloc_state
= sa_none
;
6399 struct sched_domain
*sd
;
6401 int i
, ret
= -ENOMEM
;
6403 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6404 if (alloc_state
!= sa_rootdomain
)
6407 /* Set up domains for cpus specified by the cpu_map. */
6408 for_each_cpu(i
, cpu_map
) {
6409 struct sched_domain_topology_level
*tl
;
6412 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6413 sd
= build_sched_domain(tl
, &d
, cpu_map
, attr
, sd
, i
);
6414 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6415 sd
->flags
|= SD_OVERLAP
;
6416 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6423 *per_cpu_ptr(d
.sd
, i
) = sd
;
6426 /* Build the groups for the domains */
6427 for_each_cpu(i
, cpu_map
) {
6428 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6429 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6430 if (sd
->flags
& SD_OVERLAP
) {
6431 if (build_overlap_sched_groups(sd
, i
))
6434 if (build_sched_groups(sd
, i
))
6440 /* Calculate CPU power for physical packages and nodes */
6441 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6442 if (!cpumask_test_cpu(i
, cpu_map
))
6445 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6446 claim_allocations(i
, sd
);
6447 init_sched_groups_power(i
, sd
);
6451 /* Attach the domains */
6453 for_each_cpu(i
, cpu_map
) {
6454 sd
= *per_cpu_ptr(d
.sd
, i
);
6455 cpu_attach_domain(sd
, d
.rd
, i
);
6461 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6465 static cpumask_var_t
*doms_cur
; /* current sched domains */
6466 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6467 static struct sched_domain_attr
*dattr_cur
;
6468 /* attribues of custom domains in 'doms_cur' */
6471 * Special case: If a kmalloc of a doms_cur partition (array of
6472 * cpumask) fails, then fallback to a single sched domain,
6473 * as determined by the single cpumask fallback_doms.
6475 static cpumask_var_t fallback_doms
;
6478 * arch_update_cpu_topology lets virtualized architectures update the
6479 * cpu core maps. It is supposed to return 1 if the topology changed
6480 * or 0 if it stayed the same.
6482 int __attribute__((weak
)) arch_update_cpu_topology(void)
6487 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6490 cpumask_var_t
*doms
;
6492 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6495 for (i
= 0; i
< ndoms
; i
++) {
6496 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6497 free_sched_domains(doms
, i
);
6504 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6507 for (i
= 0; i
< ndoms
; i
++)
6508 free_cpumask_var(doms
[i
]);
6513 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6514 * For now this just excludes isolated cpus, but could be used to
6515 * exclude other special cases in the future.
6517 static int init_sched_domains(const struct cpumask
*cpu_map
)
6521 arch_update_cpu_topology();
6523 doms_cur
= alloc_sched_domains(ndoms_cur
);
6525 doms_cur
= &fallback_doms
;
6526 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6527 err
= build_sched_domains(doms_cur
[0], NULL
);
6528 register_sched_domain_sysctl();
6534 * Detach sched domains from a group of cpus specified in cpu_map
6535 * These cpus will now be attached to the NULL domain
6537 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6542 for_each_cpu(i
, cpu_map
)
6543 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6547 /* handle null as "default" */
6548 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6549 struct sched_domain_attr
*new, int idx_new
)
6551 struct sched_domain_attr tmp
;
6558 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6559 new ? (new + idx_new
) : &tmp
,
6560 sizeof(struct sched_domain_attr
));
6564 * Partition sched domains as specified by the 'ndoms_new'
6565 * cpumasks in the array doms_new[] of cpumasks. This compares
6566 * doms_new[] to the current sched domain partitioning, doms_cur[].
6567 * It destroys each deleted domain and builds each new domain.
6569 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6570 * The masks don't intersect (don't overlap.) We should setup one
6571 * sched domain for each mask. CPUs not in any of the cpumasks will
6572 * not be load balanced. If the same cpumask appears both in the
6573 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6576 * The passed in 'doms_new' should be allocated using
6577 * alloc_sched_domains. This routine takes ownership of it and will
6578 * free_sched_domains it when done with it. If the caller failed the
6579 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6580 * and partition_sched_domains() will fallback to the single partition
6581 * 'fallback_doms', it also forces the domains to be rebuilt.
6583 * If doms_new == NULL it will be replaced with cpu_online_mask.
6584 * ndoms_new == 0 is a special case for destroying existing domains,
6585 * and it will not create the default domain.
6587 * Call with hotplug lock held
6589 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6590 struct sched_domain_attr
*dattr_new
)
6595 mutex_lock(&sched_domains_mutex
);
6597 /* always unregister in case we don't destroy any domains */
6598 unregister_sched_domain_sysctl();
6600 /* Let architecture update cpu core mappings. */
6601 new_topology
= arch_update_cpu_topology();
6603 n
= doms_new
? ndoms_new
: 0;
6605 /* Destroy deleted domains */
6606 for (i
= 0; i
< ndoms_cur
; i
++) {
6607 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6608 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6609 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6612 /* no match - a current sched domain not in new doms_new[] */
6613 detach_destroy_domains(doms_cur
[i
]);
6618 if (doms_new
== NULL
) {
6620 doms_new
= &fallback_doms
;
6621 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6622 WARN_ON_ONCE(dattr_new
);
6625 /* Build new domains */
6626 for (i
= 0; i
< ndoms_new
; i
++) {
6627 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
6628 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6629 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6632 /* no match - add a new doms_new */
6633 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6638 /* Remember the new sched domains */
6639 if (doms_cur
!= &fallback_doms
)
6640 free_sched_domains(doms_cur
, ndoms_cur
);
6641 kfree(dattr_cur
); /* kfree(NULL) is safe */
6642 doms_cur
= doms_new
;
6643 dattr_cur
= dattr_new
;
6644 ndoms_cur
= ndoms_new
;
6646 register_sched_domain_sysctl();
6648 mutex_unlock(&sched_domains_mutex
);
6651 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6654 * Update cpusets according to cpu_active mask. If cpusets are
6655 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6656 * around partition_sched_domains().
6658 * If we come here as part of a suspend/resume, don't touch cpusets because we
6659 * want to restore it back to its original state upon resume anyway.
6661 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6665 case CPU_ONLINE_FROZEN
:
6666 case CPU_DOWN_FAILED_FROZEN
:
6669 * num_cpus_frozen tracks how many CPUs are involved in suspend
6670 * resume sequence. As long as this is not the last online
6671 * operation in the resume sequence, just build a single sched
6672 * domain, ignoring cpusets.
6675 if (likely(num_cpus_frozen
)) {
6676 partition_sched_domains(1, NULL
, NULL
);
6681 * This is the last CPU online operation. So fall through and
6682 * restore the original sched domains by considering the
6683 * cpuset configurations.
6687 case CPU_DOWN_FAILED
:
6688 cpuset_update_active_cpus(true);
6696 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6700 case CPU_DOWN_PREPARE
:
6701 cpuset_update_active_cpus(false);
6703 case CPU_DOWN_PREPARE_FROZEN
:
6705 partition_sched_domains(1, NULL
, NULL
);
6713 void __init
sched_init_smp(void)
6715 cpumask_var_t non_isolated_cpus
;
6717 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6718 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6723 mutex_lock(&sched_domains_mutex
);
6724 init_sched_domains(cpu_active_mask
);
6725 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6726 if (cpumask_empty(non_isolated_cpus
))
6727 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6728 mutex_unlock(&sched_domains_mutex
);
6731 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
6732 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6733 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6735 /* RT runtime code needs to handle some hotplug events */
6736 hotcpu_notifier(update_runtime
, 0);
6740 /* Move init over to a non-isolated CPU */
6741 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6743 sched_init_granularity();
6744 free_cpumask_var(non_isolated_cpus
);
6746 init_sched_rt_class();
6749 void __init
sched_init_smp(void)
6751 sched_init_granularity();
6753 #endif /* CONFIG_SMP */
6755 const_debug
unsigned int sysctl_timer_migration
= 1;
6757 int in_sched_functions(unsigned long addr
)
6759 return in_lock_functions(addr
) ||
6760 (addr
>= (unsigned long)__sched_text_start
6761 && addr
< (unsigned long)__sched_text_end
);
6764 #ifdef CONFIG_CGROUP_SCHED
6765 struct task_group root_task_group
;
6766 LIST_HEAD(task_groups
);
6769 DECLARE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
6771 void __init
sched_init(void)
6774 unsigned long alloc_size
= 0, ptr
;
6776 #ifdef CONFIG_FAIR_GROUP_SCHED
6777 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6779 #ifdef CONFIG_RT_GROUP_SCHED
6780 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6782 #ifdef CONFIG_CPUMASK_OFFSTACK
6783 alloc_size
+= num_possible_cpus() * cpumask_size();
6786 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6788 #ifdef CONFIG_FAIR_GROUP_SCHED
6789 root_task_group
.se
= (struct sched_entity
**)ptr
;
6790 ptr
+= nr_cpu_ids
* sizeof(void **);
6792 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6793 ptr
+= nr_cpu_ids
* sizeof(void **);
6795 #endif /* CONFIG_FAIR_GROUP_SCHED */
6796 #ifdef CONFIG_RT_GROUP_SCHED
6797 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6798 ptr
+= nr_cpu_ids
* sizeof(void **);
6800 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6801 ptr
+= nr_cpu_ids
* sizeof(void **);
6803 #endif /* CONFIG_RT_GROUP_SCHED */
6804 #ifdef CONFIG_CPUMASK_OFFSTACK
6805 for_each_possible_cpu(i
) {
6806 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
6807 ptr
+= cpumask_size();
6809 #endif /* CONFIG_CPUMASK_OFFSTACK */
6813 init_defrootdomain();
6816 init_rt_bandwidth(&def_rt_bandwidth
,
6817 global_rt_period(), global_rt_runtime());
6819 #ifdef CONFIG_RT_GROUP_SCHED
6820 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6821 global_rt_period(), global_rt_runtime());
6822 #endif /* CONFIG_RT_GROUP_SCHED */
6824 #ifdef CONFIG_CGROUP_SCHED
6825 list_add(&root_task_group
.list
, &task_groups
);
6826 INIT_LIST_HEAD(&root_task_group
.children
);
6827 INIT_LIST_HEAD(&root_task_group
.siblings
);
6828 autogroup_init(&init_task
);
6830 #endif /* CONFIG_CGROUP_SCHED */
6832 #ifdef CONFIG_CGROUP_CPUACCT
6833 root_cpuacct
.cpustat
= &kernel_cpustat
;
6834 root_cpuacct
.cpuusage
= alloc_percpu(u64
);
6835 /* Too early, not expected to fail */
6836 BUG_ON(!root_cpuacct
.cpuusage
);
6838 for_each_possible_cpu(i
) {
6842 raw_spin_lock_init(&rq
->lock
);
6844 rq
->calc_load_active
= 0;
6845 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6846 init_cfs_rq(&rq
->cfs
);
6847 init_rt_rq(&rq
->rt
, rq
);
6848 #ifdef CONFIG_FAIR_GROUP_SCHED
6849 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6850 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6852 * How much cpu bandwidth does root_task_group get?
6854 * In case of task-groups formed thr' the cgroup filesystem, it
6855 * gets 100% of the cpu resources in the system. This overall
6856 * system cpu resource is divided among the tasks of
6857 * root_task_group and its child task-groups in a fair manner,
6858 * based on each entity's (task or task-group's) weight
6859 * (se->load.weight).
6861 * In other words, if root_task_group has 10 tasks of weight
6862 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6863 * then A0's share of the cpu resource is:
6865 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6867 * We achieve this by letting root_task_group's tasks sit
6868 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6870 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6871 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6872 #endif /* CONFIG_FAIR_GROUP_SCHED */
6874 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6875 #ifdef CONFIG_RT_GROUP_SCHED
6876 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
6877 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6880 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6881 rq
->cpu_load
[j
] = 0;
6883 rq
->last_load_update_tick
= jiffies
;
6888 rq
->cpu_power
= SCHED_POWER_SCALE
;
6889 rq
->post_schedule
= 0;
6890 rq
->active_balance
= 0;
6891 rq
->next_balance
= jiffies
;
6896 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
6898 INIT_LIST_HEAD(&rq
->cfs_tasks
);
6900 rq_attach_root(rq
, &def_root_domain
);
6906 atomic_set(&rq
->nr_iowait
, 0);
6909 set_load_weight(&init_task
);
6911 #ifdef CONFIG_PREEMPT_NOTIFIERS
6912 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
6915 #ifdef CONFIG_RT_MUTEXES
6916 plist_head_init(&init_task
.pi_waiters
);
6920 * The boot idle thread does lazy MMU switching as well:
6922 atomic_inc(&init_mm
.mm_count
);
6923 enter_lazy_tlb(&init_mm
, current
);
6926 * Make us the idle thread. Technically, schedule() should not be
6927 * called from this thread, however somewhere below it might be,
6928 * but because we are the idle thread, we just pick up running again
6929 * when this runqueue becomes "idle".
6931 init_idle(current
, smp_processor_id());
6933 calc_load_update
= jiffies
+ LOAD_FREQ
;
6936 * During early bootup we pretend to be a normal task:
6938 current
->sched_class
= &fair_sched_class
;
6941 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
6942 /* May be allocated at isolcpus cmdline parse time */
6943 if (cpu_isolated_map
== NULL
)
6944 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
6945 idle_thread_set_boot_cpu();
6947 init_sched_fair_class();
6949 scheduler_running
= 1;
6952 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6953 static inline int preempt_count_equals(int preempt_offset
)
6955 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
6957 return (nested
== preempt_offset
);
6960 void __might_sleep(const char *file
, int line
, int preempt_offset
)
6962 static unsigned long prev_jiffy
; /* ratelimiting */
6964 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
6965 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
6966 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
6968 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
6970 prev_jiffy
= jiffies
;
6973 "BUG: sleeping function called from invalid context at %s:%d\n",
6976 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
6977 in_atomic(), irqs_disabled(),
6978 current
->pid
, current
->comm
);
6980 debug_show_held_locks(current
);
6981 if (irqs_disabled())
6982 print_irqtrace_events(current
);
6985 EXPORT_SYMBOL(__might_sleep
);
6988 #ifdef CONFIG_MAGIC_SYSRQ
6989 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
6991 const struct sched_class
*prev_class
= p
->sched_class
;
6992 int old_prio
= p
->prio
;
6997 dequeue_task(rq
, p
, 0);
6998 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7000 enqueue_task(rq
, p
, 0);
7001 resched_task(rq
->curr
);
7004 check_class_changed(rq
, p
, prev_class
, old_prio
);
7007 void normalize_rt_tasks(void)
7009 struct task_struct
*g
, *p
;
7010 unsigned long flags
;
7013 read_lock_irqsave(&tasklist_lock
, flags
);
7014 do_each_thread(g
, p
) {
7016 * Only normalize user tasks:
7021 p
->se
.exec_start
= 0;
7022 #ifdef CONFIG_SCHEDSTATS
7023 p
->se
.statistics
.wait_start
= 0;
7024 p
->se
.statistics
.sleep_start
= 0;
7025 p
->se
.statistics
.block_start
= 0;
7030 * Renice negative nice level userspace
7033 if (TASK_NICE(p
) < 0 && p
->mm
)
7034 set_user_nice(p
, 0);
7038 raw_spin_lock(&p
->pi_lock
);
7039 rq
= __task_rq_lock(p
);
7041 normalize_task(rq
, p
);
7043 __task_rq_unlock(rq
);
7044 raw_spin_unlock(&p
->pi_lock
);
7045 } while_each_thread(g
, p
);
7047 read_unlock_irqrestore(&tasklist_lock
, flags
);
7050 #endif /* CONFIG_MAGIC_SYSRQ */
7052 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7054 * These functions are only useful for the IA64 MCA handling, or kdb.
7056 * They can only be called when the whole system has been
7057 * stopped - every CPU needs to be quiescent, and no scheduling
7058 * activity can take place. Using them for anything else would
7059 * be a serious bug, and as a result, they aren't even visible
7060 * under any other configuration.
7064 * curr_task - return the current task for a given cpu.
7065 * @cpu: the processor in question.
7067 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7069 struct task_struct
*curr_task(int cpu
)
7071 return cpu_curr(cpu
);
7074 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7078 * set_curr_task - set the current task for a given cpu.
7079 * @cpu: the processor in question.
7080 * @p: the task pointer to set.
7082 * Description: This function must only be used when non-maskable interrupts
7083 * are serviced on a separate stack. It allows the architecture to switch the
7084 * notion of the current task on a cpu in a non-blocking manner. This function
7085 * must be called with all CPU's synchronized, and interrupts disabled, the
7086 * and caller must save the original value of the current task (see
7087 * curr_task() above) and restore that value before reenabling interrupts and
7088 * re-starting the system.
7090 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7092 void set_curr_task(int cpu
, struct task_struct
*p
)
7099 #ifdef CONFIG_CGROUP_SCHED
7100 /* task_group_lock serializes the addition/removal of task groups */
7101 static DEFINE_SPINLOCK(task_group_lock
);
7103 static void free_sched_group(struct task_group
*tg
)
7105 free_fair_sched_group(tg
);
7106 free_rt_sched_group(tg
);
7111 /* allocate runqueue etc for a new task group */
7112 struct task_group
*sched_create_group(struct task_group
*parent
)
7114 struct task_group
*tg
;
7115 unsigned long flags
;
7117 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7119 return ERR_PTR(-ENOMEM
);
7121 if (!alloc_fair_sched_group(tg
, parent
))
7124 if (!alloc_rt_sched_group(tg
, parent
))
7127 spin_lock_irqsave(&task_group_lock
, flags
);
7128 list_add_rcu(&tg
->list
, &task_groups
);
7130 WARN_ON(!parent
); /* root should already exist */
7132 tg
->parent
= parent
;
7133 INIT_LIST_HEAD(&tg
->children
);
7134 list_add_rcu(&tg
->siblings
, &parent
->children
);
7135 spin_unlock_irqrestore(&task_group_lock
, flags
);
7140 free_sched_group(tg
);
7141 return ERR_PTR(-ENOMEM
);
7144 /* rcu callback to free various structures associated with a task group */
7145 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7147 /* now it should be safe to free those cfs_rqs */
7148 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7151 /* Destroy runqueue etc associated with a task group */
7152 void sched_destroy_group(struct task_group
*tg
)
7154 unsigned long flags
;
7157 /* end participation in shares distribution */
7158 for_each_possible_cpu(i
)
7159 unregister_fair_sched_group(tg
, i
);
7161 spin_lock_irqsave(&task_group_lock
, flags
);
7162 list_del_rcu(&tg
->list
);
7163 list_del_rcu(&tg
->siblings
);
7164 spin_unlock_irqrestore(&task_group_lock
, flags
);
7166 /* wait for possible concurrent references to cfs_rqs complete */
7167 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7170 /* change task's runqueue when it moves between groups.
7171 * The caller of this function should have put the task in its new group
7172 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7173 * reflect its new group.
7175 void sched_move_task(struct task_struct
*tsk
)
7177 struct task_group
*tg
;
7179 unsigned long flags
;
7182 rq
= task_rq_lock(tsk
, &flags
);
7184 running
= task_current(rq
, tsk
);
7188 dequeue_task(rq
, tsk
, 0);
7189 if (unlikely(running
))
7190 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7192 tg
= container_of(task_subsys_state_check(tsk
, cpu_cgroup_subsys_id
,
7193 lockdep_is_held(&tsk
->sighand
->siglock
)),
7194 struct task_group
, css
);
7195 tg
= autogroup_task_group(tsk
, tg
);
7196 tsk
->sched_task_group
= tg
;
7198 #ifdef CONFIG_FAIR_GROUP_SCHED
7199 if (tsk
->sched_class
->task_move_group
)
7200 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
7203 set_task_rq(tsk
, task_cpu(tsk
));
7205 if (unlikely(running
))
7206 tsk
->sched_class
->set_curr_task(rq
);
7208 enqueue_task(rq
, tsk
, 0);
7210 task_rq_unlock(rq
, tsk
, &flags
);
7212 #endif /* CONFIG_CGROUP_SCHED */
7214 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
7215 static unsigned long to_ratio(u64 period
, u64 runtime
)
7217 if (runtime
== RUNTIME_INF
)
7220 return div64_u64(runtime
<< 20, period
);
7224 #ifdef CONFIG_RT_GROUP_SCHED
7226 * Ensure that the real time constraints are schedulable.
7228 static DEFINE_MUTEX(rt_constraints_mutex
);
7230 /* Must be called with tasklist_lock held */
7231 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7233 struct task_struct
*g
, *p
;
7235 do_each_thread(g
, p
) {
7236 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
7238 } while_each_thread(g
, p
);
7243 struct rt_schedulable_data
{
7244 struct task_group
*tg
;
7249 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7251 struct rt_schedulable_data
*d
= data
;
7252 struct task_group
*child
;
7253 unsigned long total
, sum
= 0;
7254 u64 period
, runtime
;
7256 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7257 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7260 period
= d
->rt_period
;
7261 runtime
= d
->rt_runtime
;
7265 * Cannot have more runtime than the period.
7267 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7271 * Ensure we don't starve existing RT tasks.
7273 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7276 total
= to_ratio(period
, runtime
);
7279 * Nobody can have more than the global setting allows.
7281 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7285 * The sum of our children's runtime should not exceed our own.
7287 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7288 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7289 runtime
= child
->rt_bandwidth
.rt_runtime
;
7291 if (child
== d
->tg
) {
7292 period
= d
->rt_period
;
7293 runtime
= d
->rt_runtime
;
7296 sum
+= to_ratio(period
, runtime
);
7305 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7309 struct rt_schedulable_data data
= {
7311 .rt_period
= period
,
7312 .rt_runtime
= runtime
,
7316 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7322 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7323 u64 rt_period
, u64 rt_runtime
)
7327 mutex_lock(&rt_constraints_mutex
);
7328 read_lock(&tasklist_lock
);
7329 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7333 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7334 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7335 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7337 for_each_possible_cpu(i
) {
7338 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7340 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7341 rt_rq
->rt_runtime
= rt_runtime
;
7342 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7344 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7346 read_unlock(&tasklist_lock
);
7347 mutex_unlock(&rt_constraints_mutex
);
7352 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7354 u64 rt_runtime
, rt_period
;
7356 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7357 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7358 if (rt_runtime_us
< 0)
7359 rt_runtime
= RUNTIME_INF
;
7361 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7364 long sched_group_rt_runtime(struct task_group
*tg
)
7368 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7371 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7372 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7373 return rt_runtime_us
;
7376 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7378 u64 rt_runtime
, rt_period
;
7380 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7381 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7386 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7389 long sched_group_rt_period(struct task_group
*tg
)
7393 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7394 do_div(rt_period_us
, NSEC_PER_USEC
);
7395 return rt_period_us
;
7398 static int sched_rt_global_constraints(void)
7400 u64 runtime
, period
;
7403 if (sysctl_sched_rt_period
<= 0)
7406 runtime
= global_rt_runtime();
7407 period
= global_rt_period();
7410 * Sanity check on the sysctl variables.
7412 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7415 mutex_lock(&rt_constraints_mutex
);
7416 read_lock(&tasklist_lock
);
7417 ret
= __rt_schedulable(NULL
, 0, 0);
7418 read_unlock(&tasklist_lock
);
7419 mutex_unlock(&rt_constraints_mutex
);
7424 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7426 /* Don't accept realtime tasks when there is no way for them to run */
7427 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7433 #else /* !CONFIG_RT_GROUP_SCHED */
7434 static int sched_rt_global_constraints(void)
7436 unsigned long flags
;
7439 if (sysctl_sched_rt_period
<= 0)
7443 * There's always some RT tasks in the root group
7444 * -- migration, kstopmachine etc..
7446 if (sysctl_sched_rt_runtime
== 0)
7449 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7450 for_each_possible_cpu(i
) {
7451 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7453 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7454 rt_rq
->rt_runtime
= global_rt_runtime();
7455 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7457 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7461 #endif /* CONFIG_RT_GROUP_SCHED */
7463 int sched_rt_handler(struct ctl_table
*table
, int write
,
7464 void __user
*buffer
, size_t *lenp
,
7468 int old_period
, old_runtime
;
7469 static DEFINE_MUTEX(mutex
);
7472 old_period
= sysctl_sched_rt_period
;
7473 old_runtime
= sysctl_sched_rt_runtime
;
7475 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7477 if (!ret
&& write
) {
7478 ret
= sched_rt_global_constraints();
7480 sysctl_sched_rt_period
= old_period
;
7481 sysctl_sched_rt_runtime
= old_runtime
;
7483 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7484 def_rt_bandwidth
.rt_period
=
7485 ns_to_ktime(global_rt_period());
7488 mutex_unlock(&mutex
);
7493 #ifdef CONFIG_CGROUP_SCHED
7495 /* return corresponding task_group object of a cgroup */
7496 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
7498 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
7499 struct task_group
, css
);
7502 static struct cgroup_subsys_state
*cpu_cgroup_css_alloc(struct cgroup
*cgrp
)
7504 struct task_group
*tg
, *parent
;
7506 if (!cgrp
->parent
) {
7507 /* This is early initialization for the top cgroup */
7508 return &root_task_group
.css
;
7511 parent
= cgroup_tg(cgrp
->parent
);
7512 tg
= sched_create_group(parent
);
7514 return ERR_PTR(-ENOMEM
);
7519 static void cpu_cgroup_css_free(struct cgroup
*cgrp
)
7521 struct task_group
*tg
= cgroup_tg(cgrp
);
7523 sched_destroy_group(tg
);
7526 static int cpu_cgroup_can_attach(struct cgroup
*cgrp
,
7527 struct cgroup_taskset
*tset
)
7529 struct task_struct
*task
;
7531 cgroup_taskset_for_each(task
, cgrp
, tset
) {
7532 #ifdef CONFIG_RT_GROUP_SCHED
7533 if (!sched_rt_can_attach(cgroup_tg(cgrp
), task
))
7536 /* We don't support RT-tasks being in separate groups */
7537 if (task
->sched_class
!= &fair_sched_class
)
7544 static void cpu_cgroup_attach(struct cgroup
*cgrp
,
7545 struct cgroup_taskset
*tset
)
7547 struct task_struct
*task
;
7549 cgroup_taskset_for_each(task
, cgrp
, tset
)
7550 sched_move_task(task
);
7554 cpu_cgroup_exit(struct cgroup
*cgrp
, struct cgroup
*old_cgrp
,
7555 struct task_struct
*task
)
7558 * cgroup_exit() is called in the copy_process() failure path.
7559 * Ignore this case since the task hasn't ran yet, this avoids
7560 * trying to poke a half freed task state from generic code.
7562 if (!(task
->flags
& PF_EXITING
))
7565 sched_move_task(task
);
7568 #ifdef CONFIG_FAIR_GROUP_SCHED
7569 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7572 return sched_group_set_shares(cgroup_tg(cgrp
), scale_load(shareval
));
7575 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7577 struct task_group
*tg
= cgroup_tg(cgrp
);
7579 return (u64
) scale_load_down(tg
->shares
);
7582 #ifdef CONFIG_CFS_BANDWIDTH
7583 static DEFINE_MUTEX(cfs_constraints_mutex
);
7585 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7586 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7588 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7590 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7592 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7593 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7595 if (tg
== &root_task_group
)
7599 * Ensure we have at some amount of bandwidth every period. This is
7600 * to prevent reaching a state of large arrears when throttled via
7601 * entity_tick() resulting in prolonged exit starvation.
7603 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7607 * Likewise, bound things on the otherside by preventing insane quota
7608 * periods. This also allows us to normalize in computing quota
7611 if (period
> max_cfs_quota_period
)
7614 mutex_lock(&cfs_constraints_mutex
);
7615 ret
= __cfs_schedulable(tg
, period
, quota
);
7619 runtime_enabled
= quota
!= RUNTIME_INF
;
7620 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7621 account_cfs_bandwidth_used(runtime_enabled
, runtime_was_enabled
);
7622 raw_spin_lock_irq(&cfs_b
->lock
);
7623 cfs_b
->period
= ns_to_ktime(period
);
7624 cfs_b
->quota
= quota
;
7626 __refill_cfs_bandwidth_runtime(cfs_b
);
7627 /* restart the period timer (if active) to handle new period expiry */
7628 if (runtime_enabled
&& cfs_b
->timer_active
) {
7629 /* force a reprogram */
7630 cfs_b
->timer_active
= 0;
7631 __start_cfs_bandwidth(cfs_b
);
7633 raw_spin_unlock_irq(&cfs_b
->lock
);
7635 for_each_possible_cpu(i
) {
7636 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7637 struct rq
*rq
= cfs_rq
->rq
;
7639 raw_spin_lock_irq(&rq
->lock
);
7640 cfs_rq
->runtime_enabled
= runtime_enabled
;
7641 cfs_rq
->runtime_remaining
= 0;
7643 if (cfs_rq
->throttled
)
7644 unthrottle_cfs_rq(cfs_rq
);
7645 raw_spin_unlock_irq(&rq
->lock
);
7648 mutex_unlock(&cfs_constraints_mutex
);
7653 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7657 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7658 if (cfs_quota_us
< 0)
7659 quota
= RUNTIME_INF
;
7661 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7663 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7666 long tg_get_cfs_quota(struct task_group
*tg
)
7670 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7673 quota_us
= tg
->cfs_bandwidth
.quota
;
7674 do_div(quota_us
, NSEC_PER_USEC
);
7679 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7683 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7684 quota
= tg
->cfs_bandwidth
.quota
;
7686 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7689 long tg_get_cfs_period(struct task_group
*tg
)
7693 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7694 do_div(cfs_period_us
, NSEC_PER_USEC
);
7696 return cfs_period_us
;
7699 static s64
cpu_cfs_quota_read_s64(struct cgroup
*cgrp
, struct cftype
*cft
)
7701 return tg_get_cfs_quota(cgroup_tg(cgrp
));
7704 static int cpu_cfs_quota_write_s64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7707 return tg_set_cfs_quota(cgroup_tg(cgrp
), cfs_quota_us
);
7710 static u64
cpu_cfs_period_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7712 return tg_get_cfs_period(cgroup_tg(cgrp
));
7715 static int cpu_cfs_period_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7718 return tg_set_cfs_period(cgroup_tg(cgrp
), cfs_period_us
);
7721 struct cfs_schedulable_data
{
7722 struct task_group
*tg
;
7727 * normalize group quota/period to be quota/max_period
7728 * note: units are usecs
7730 static u64
normalize_cfs_quota(struct task_group
*tg
,
7731 struct cfs_schedulable_data
*d
)
7739 period
= tg_get_cfs_period(tg
);
7740 quota
= tg_get_cfs_quota(tg
);
7743 /* note: these should typically be equivalent */
7744 if (quota
== RUNTIME_INF
|| quota
== -1)
7747 return to_ratio(period
, quota
);
7750 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7752 struct cfs_schedulable_data
*d
= data
;
7753 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7754 s64 quota
= 0, parent_quota
= -1;
7757 quota
= RUNTIME_INF
;
7759 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
7761 quota
= normalize_cfs_quota(tg
, d
);
7762 parent_quota
= parent_b
->hierarchal_quota
;
7765 * ensure max(child_quota) <= parent_quota, inherit when no
7768 if (quota
== RUNTIME_INF
)
7769 quota
= parent_quota
;
7770 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
7773 cfs_b
->hierarchal_quota
= quota
;
7778 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
7781 struct cfs_schedulable_data data
= {
7787 if (quota
!= RUNTIME_INF
) {
7788 do_div(data
.period
, NSEC_PER_USEC
);
7789 do_div(data
.quota
, NSEC_PER_USEC
);
7793 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
7799 static int cpu_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
7800 struct cgroup_map_cb
*cb
)
7802 struct task_group
*tg
= cgroup_tg(cgrp
);
7803 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7805 cb
->fill(cb
, "nr_periods", cfs_b
->nr_periods
);
7806 cb
->fill(cb
, "nr_throttled", cfs_b
->nr_throttled
);
7807 cb
->fill(cb
, "throttled_time", cfs_b
->throttled_time
);
7811 #endif /* CONFIG_CFS_BANDWIDTH */
7812 #endif /* CONFIG_FAIR_GROUP_SCHED */
7814 #ifdef CONFIG_RT_GROUP_SCHED
7815 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
7818 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
7821 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
7823 return sched_group_rt_runtime(cgroup_tg(cgrp
));
7826 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
7829 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
7832 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
7834 return sched_group_rt_period(cgroup_tg(cgrp
));
7836 #endif /* CONFIG_RT_GROUP_SCHED */
7838 static struct cftype cpu_files
[] = {
7839 #ifdef CONFIG_FAIR_GROUP_SCHED
7842 .read_u64
= cpu_shares_read_u64
,
7843 .write_u64
= cpu_shares_write_u64
,
7846 #ifdef CONFIG_CFS_BANDWIDTH
7848 .name
= "cfs_quota_us",
7849 .read_s64
= cpu_cfs_quota_read_s64
,
7850 .write_s64
= cpu_cfs_quota_write_s64
,
7853 .name
= "cfs_period_us",
7854 .read_u64
= cpu_cfs_period_read_u64
,
7855 .write_u64
= cpu_cfs_period_write_u64
,
7859 .read_map
= cpu_stats_show
,
7862 #ifdef CONFIG_RT_GROUP_SCHED
7864 .name
= "rt_runtime_us",
7865 .read_s64
= cpu_rt_runtime_read
,
7866 .write_s64
= cpu_rt_runtime_write
,
7869 .name
= "rt_period_us",
7870 .read_u64
= cpu_rt_period_read_uint
,
7871 .write_u64
= cpu_rt_period_write_uint
,
7877 struct cgroup_subsys cpu_cgroup_subsys
= {
7879 .css_alloc
= cpu_cgroup_css_alloc
,
7880 .css_free
= cpu_cgroup_css_free
,
7881 .can_attach
= cpu_cgroup_can_attach
,
7882 .attach
= cpu_cgroup_attach
,
7883 .exit
= cpu_cgroup_exit
,
7884 .subsys_id
= cpu_cgroup_subsys_id
,
7885 .base_cftypes
= cpu_files
,
7889 #endif /* CONFIG_CGROUP_SCHED */
7891 #ifdef CONFIG_CGROUP_CPUACCT
7894 * CPU accounting code for task groups.
7896 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
7897 * (balbir@in.ibm.com).
7900 struct cpuacct root_cpuacct
;
7902 /* create a new cpu accounting group */
7903 static struct cgroup_subsys_state
*cpuacct_css_alloc(struct cgroup
*cgrp
)
7908 return &root_cpuacct
.css
;
7910 ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
7914 ca
->cpuusage
= alloc_percpu(u64
);
7918 ca
->cpustat
= alloc_percpu(struct kernel_cpustat
);
7920 goto out_free_cpuusage
;
7925 free_percpu(ca
->cpuusage
);
7929 return ERR_PTR(-ENOMEM
);
7932 /* destroy an existing cpu accounting group */
7933 static void cpuacct_css_free(struct cgroup
*cgrp
)
7935 struct cpuacct
*ca
= cgroup_ca(cgrp
);
7937 free_percpu(ca
->cpustat
);
7938 free_percpu(ca
->cpuusage
);
7942 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
7944 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
7947 #ifndef CONFIG_64BIT
7949 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
7951 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
7953 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
7961 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
7963 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
7965 #ifndef CONFIG_64BIT
7967 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
7969 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
7971 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
7977 /* return total cpu usage (in nanoseconds) of a group */
7978 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
7980 struct cpuacct
*ca
= cgroup_ca(cgrp
);
7981 u64 totalcpuusage
= 0;
7984 for_each_present_cpu(i
)
7985 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
7987 return totalcpuusage
;
7990 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
7993 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8002 for_each_present_cpu(i
)
8003 cpuacct_cpuusage_write(ca
, i
, 0);
8009 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
8012 struct cpuacct
*ca
= cgroup_ca(cgroup
);
8016 for_each_present_cpu(i
) {
8017 percpu
= cpuacct_cpuusage_read(ca
, i
);
8018 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
8020 seq_printf(m
, "\n");
8024 static const char *cpuacct_stat_desc
[] = {
8025 [CPUACCT_STAT_USER
] = "user",
8026 [CPUACCT_STAT_SYSTEM
] = "system",
8029 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
8030 struct cgroup_map_cb
*cb
)
8032 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8036 for_each_online_cpu(cpu
) {
8037 struct kernel_cpustat
*kcpustat
= per_cpu_ptr(ca
->cpustat
, cpu
);
8038 val
+= kcpustat
->cpustat
[CPUTIME_USER
];
8039 val
+= kcpustat
->cpustat
[CPUTIME_NICE
];
8041 val
= cputime64_to_clock_t(val
);
8042 cb
->fill(cb
, cpuacct_stat_desc
[CPUACCT_STAT_USER
], val
);
8045 for_each_online_cpu(cpu
) {
8046 struct kernel_cpustat
*kcpustat
= per_cpu_ptr(ca
->cpustat
, cpu
);
8047 val
+= kcpustat
->cpustat
[CPUTIME_SYSTEM
];
8048 val
+= kcpustat
->cpustat
[CPUTIME_IRQ
];
8049 val
+= kcpustat
->cpustat
[CPUTIME_SOFTIRQ
];
8052 val
= cputime64_to_clock_t(val
);
8053 cb
->fill(cb
, cpuacct_stat_desc
[CPUACCT_STAT_SYSTEM
], val
);
8058 static struct cftype files
[] = {
8061 .read_u64
= cpuusage_read
,
8062 .write_u64
= cpuusage_write
,
8065 .name
= "usage_percpu",
8066 .read_seq_string
= cpuacct_percpu_seq_read
,
8070 .read_map
= cpuacct_stats_show
,
8076 * charge this task's execution time to its accounting group.
8078 * called with rq->lock held.
8080 void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8085 if (unlikely(!cpuacct_subsys
.active
))
8088 cpu
= task_cpu(tsk
);
8094 for (; ca
; ca
= parent_ca(ca
)) {
8095 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8096 *cpuusage
+= cputime
;
8102 struct cgroup_subsys cpuacct_subsys
= {
8104 .css_alloc
= cpuacct_css_alloc
,
8105 .css_free
= cpuacct_css_free
,
8106 .subsys_id
= cpuacct_subsys_id
,
8107 .base_cftypes
= files
,
8109 #endif /* CONFIG_CGROUP_CPUACCT */
8111 void dump_cpu_task(int cpu
)
8113 pr_info("Task dump for CPU %d:\n", cpu
);
8114 sched_show_task(cpu_curr(cpu
));