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>
76 #include <asm/irq_regs.h>
77 #include <asm/mutex.h>
78 #ifdef CONFIG_PARAVIRT
79 #include <asm/paravirt.h>
83 #include "../workqueue_sched.h"
85 #define CREATE_TRACE_POINTS
86 #include <trace/events/sched.h>
88 void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
91 ktime_t soft
, hard
, now
;
94 if (hrtimer_active(period_timer
))
97 now
= hrtimer_cb_get_time(period_timer
);
98 hrtimer_forward(period_timer
, now
, period
);
100 soft
= hrtimer_get_softexpires(period_timer
);
101 hard
= hrtimer_get_expires(period_timer
);
102 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
103 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
104 HRTIMER_MODE_ABS_PINNED
, 0);
108 DEFINE_MUTEX(sched_domains_mutex
);
109 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
111 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
113 void update_rq_clock(struct rq
*rq
)
117 if (rq
->skip_clock_update
> 0)
120 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
122 update_rq_clock_task(rq
, delta
);
126 * Debugging: various feature bits
129 #define SCHED_FEAT(name, enabled) \
130 (1UL << __SCHED_FEAT_##name) * enabled |
132 const_debug
unsigned int sysctl_sched_features
=
133 #include "features.h"
138 #ifdef CONFIG_SCHED_DEBUG
139 #define SCHED_FEAT(name, enabled) \
142 static __read_mostly
char *sched_feat_names
[] = {
143 #include "features.h"
149 static int sched_feat_show(struct seq_file
*m
, void *v
)
153 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
154 if (!(sysctl_sched_features
& (1UL << i
)))
156 seq_printf(m
, "%s ", sched_feat_names
[i
]);
163 #ifdef HAVE_JUMP_LABEL
165 #define jump_label_key__true jump_label_key_enabled
166 #define jump_label_key__false jump_label_key_disabled
168 #define SCHED_FEAT(name, enabled) \
169 jump_label_key__##enabled ,
171 struct jump_label_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
172 #include "features.h"
177 static void sched_feat_disable(int i
)
179 if (jump_label_enabled(&sched_feat_keys
[i
]))
180 jump_label_dec(&sched_feat_keys
[i
]);
183 static void sched_feat_enable(int i
)
185 if (!jump_label_enabled(&sched_feat_keys
[i
]))
186 jump_label_inc(&sched_feat_keys
[i
]);
189 static void sched_feat_disable(int i
) { };
190 static void sched_feat_enable(int i
) { };
191 #endif /* HAVE_JUMP_LABEL */
194 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
195 size_t cnt
, loff_t
*ppos
)
205 if (copy_from_user(&buf
, ubuf
, cnt
))
211 if (strncmp(cmp
, "NO_", 3) == 0) {
216 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
217 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
219 sysctl_sched_features
&= ~(1UL << i
);
220 sched_feat_disable(i
);
222 sysctl_sched_features
|= (1UL << i
);
223 sched_feat_enable(i
);
229 if (i
== __SCHED_FEAT_NR
)
237 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
239 return single_open(filp
, sched_feat_show
, NULL
);
242 static const struct file_operations sched_feat_fops
= {
243 .open
= sched_feat_open
,
244 .write
= sched_feat_write
,
247 .release
= single_release
,
250 static __init
int sched_init_debug(void)
252 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
257 late_initcall(sched_init_debug
);
258 #endif /* CONFIG_SCHED_DEBUG */
261 * Number of tasks to iterate in a single balance run.
262 * Limited because this is done with IRQs disabled.
264 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
267 * period over which we average the RT time consumption, measured
272 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
275 * period over which we measure -rt task cpu usage in us.
278 unsigned int sysctl_sched_rt_period
= 1000000;
280 __read_mostly
int scheduler_running
;
283 * part of the period that we allow rt tasks to run in us.
286 int sysctl_sched_rt_runtime
= 950000;
291 * __task_rq_lock - lock the rq @p resides on.
293 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
298 lockdep_assert_held(&p
->pi_lock
);
302 raw_spin_lock(&rq
->lock
);
303 if (likely(rq
== task_rq(p
)))
305 raw_spin_unlock(&rq
->lock
);
310 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
312 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
313 __acquires(p
->pi_lock
)
319 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
321 raw_spin_lock(&rq
->lock
);
322 if (likely(rq
== task_rq(p
)))
324 raw_spin_unlock(&rq
->lock
);
325 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
329 static void __task_rq_unlock(struct rq
*rq
)
332 raw_spin_unlock(&rq
->lock
);
336 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
338 __releases(p
->pi_lock
)
340 raw_spin_unlock(&rq
->lock
);
341 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
345 * this_rq_lock - lock this runqueue and disable interrupts.
347 static struct rq
*this_rq_lock(void)
354 raw_spin_lock(&rq
->lock
);
359 #ifdef CONFIG_SCHED_HRTICK
361 * Use HR-timers to deliver accurate preemption points.
363 * Its all a bit involved since we cannot program an hrt while holding the
364 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
367 * When we get rescheduled we reprogram the hrtick_timer outside of the
371 static void hrtick_clear(struct rq
*rq
)
373 if (hrtimer_active(&rq
->hrtick_timer
))
374 hrtimer_cancel(&rq
->hrtick_timer
);
378 * High-resolution timer tick.
379 * Runs from hardirq context with interrupts disabled.
381 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
383 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
385 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
387 raw_spin_lock(&rq
->lock
);
389 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
390 raw_spin_unlock(&rq
->lock
);
392 return HRTIMER_NORESTART
;
397 * called from hardirq (IPI) context
399 static void __hrtick_start(void *arg
)
403 raw_spin_lock(&rq
->lock
);
404 hrtimer_restart(&rq
->hrtick_timer
);
405 rq
->hrtick_csd_pending
= 0;
406 raw_spin_unlock(&rq
->lock
);
410 * Called to set the hrtick timer state.
412 * called with rq->lock held and irqs disabled
414 void hrtick_start(struct rq
*rq
, u64 delay
)
416 struct hrtimer
*timer
= &rq
->hrtick_timer
;
417 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
419 hrtimer_set_expires(timer
, time
);
421 if (rq
== this_rq()) {
422 hrtimer_restart(timer
);
423 } else if (!rq
->hrtick_csd_pending
) {
424 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
425 rq
->hrtick_csd_pending
= 1;
430 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
432 int cpu
= (int)(long)hcpu
;
435 case CPU_UP_CANCELED
:
436 case CPU_UP_CANCELED_FROZEN
:
437 case CPU_DOWN_PREPARE
:
438 case CPU_DOWN_PREPARE_FROZEN
:
440 case CPU_DEAD_FROZEN
:
441 hrtick_clear(cpu_rq(cpu
));
448 static __init
void init_hrtick(void)
450 hotcpu_notifier(hotplug_hrtick
, 0);
454 * Called to set the hrtick timer state.
456 * called with rq->lock held and irqs disabled
458 void hrtick_start(struct rq
*rq
, u64 delay
)
460 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
461 HRTIMER_MODE_REL_PINNED
, 0);
464 static inline void init_hrtick(void)
467 #endif /* CONFIG_SMP */
469 static void init_rq_hrtick(struct rq
*rq
)
472 rq
->hrtick_csd_pending
= 0;
474 rq
->hrtick_csd
.flags
= 0;
475 rq
->hrtick_csd
.func
= __hrtick_start
;
476 rq
->hrtick_csd
.info
= rq
;
479 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
480 rq
->hrtick_timer
.function
= hrtick
;
482 #else /* CONFIG_SCHED_HRTICK */
483 static inline void hrtick_clear(struct rq
*rq
)
487 static inline void init_rq_hrtick(struct rq
*rq
)
491 static inline void init_hrtick(void)
494 #endif /* CONFIG_SCHED_HRTICK */
497 * resched_task - mark a task 'to be rescheduled now'.
499 * On UP this means the setting of the need_resched flag, on SMP it
500 * might also involve a cross-CPU call to trigger the scheduler on
505 #ifndef tsk_is_polling
506 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
509 void resched_task(struct task_struct
*p
)
513 assert_raw_spin_locked(&task_rq(p
)->lock
);
515 if (test_tsk_need_resched(p
))
518 set_tsk_need_resched(p
);
521 if (cpu
== smp_processor_id())
524 /* NEED_RESCHED must be visible before we test polling */
526 if (!tsk_is_polling(p
))
527 smp_send_reschedule(cpu
);
530 void resched_cpu(int cpu
)
532 struct rq
*rq
= cpu_rq(cpu
);
535 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
537 resched_task(cpu_curr(cpu
));
538 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
543 * In the semi idle case, use the nearest busy cpu for migrating timers
544 * from an idle cpu. This is good for power-savings.
546 * We don't do similar optimization for completely idle system, as
547 * selecting an idle cpu will add more delays to the timers than intended
548 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
550 int get_nohz_timer_target(void)
552 int cpu
= smp_processor_id();
554 struct sched_domain
*sd
;
557 for_each_domain(cpu
, sd
) {
558 for_each_cpu(i
, sched_domain_span(sd
)) {
570 * When add_timer_on() enqueues a timer into the timer wheel of an
571 * idle CPU then this timer might expire before the next timer event
572 * which is scheduled to wake up that CPU. In case of a completely
573 * idle system the next event might even be infinite time into the
574 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
575 * leaves the inner idle loop so the newly added timer is taken into
576 * account when the CPU goes back to idle and evaluates the timer
577 * wheel for the next timer event.
579 void wake_up_idle_cpu(int cpu
)
581 struct rq
*rq
= cpu_rq(cpu
);
583 if (cpu
== smp_processor_id())
587 * This is safe, as this function is called with the timer
588 * wheel base lock of (cpu) held. When the CPU is on the way
589 * to idle and has not yet set rq->curr to idle then it will
590 * be serialized on the timer wheel base lock and take the new
591 * timer into account automatically.
593 if (rq
->curr
!= rq
->idle
)
597 * We can set TIF_RESCHED on the idle task of the other CPU
598 * lockless. The worst case is that the other CPU runs the
599 * idle task through an additional NOOP schedule()
601 set_tsk_need_resched(rq
->idle
);
603 /* NEED_RESCHED must be visible before we test polling */
605 if (!tsk_is_polling(rq
->idle
))
606 smp_send_reschedule(cpu
);
609 static inline bool got_nohz_idle_kick(void)
611 int cpu
= smp_processor_id();
612 return idle_cpu(cpu
) && test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
615 #else /* CONFIG_NO_HZ */
617 static inline bool got_nohz_idle_kick(void)
622 #endif /* CONFIG_NO_HZ */
624 void sched_avg_update(struct rq
*rq
)
626 s64 period
= sched_avg_period();
628 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
630 * Inline assembly required to prevent the compiler
631 * optimising this loop into a divmod call.
632 * See __iter_div_u64_rem() for another example of this.
634 asm("" : "+rm" (rq
->age_stamp
));
635 rq
->age_stamp
+= period
;
640 #else /* !CONFIG_SMP */
641 void resched_task(struct task_struct
*p
)
643 assert_raw_spin_locked(&task_rq(p
)->lock
);
644 set_tsk_need_resched(p
);
646 #endif /* CONFIG_SMP */
648 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
649 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
651 * Iterate task_group tree rooted at *from, calling @down when first entering a
652 * node and @up when leaving it for the final time.
654 * Caller must hold rcu_lock or sufficient equivalent.
656 int walk_tg_tree_from(struct task_group
*from
,
657 tg_visitor down
, tg_visitor up
, void *data
)
659 struct task_group
*parent
, *child
;
665 ret
= (*down
)(parent
, data
);
668 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
675 ret
= (*up
)(parent
, data
);
676 if (ret
|| parent
== from
)
680 parent
= parent
->parent
;
687 int tg_nop(struct task_group
*tg
, void *data
)
693 void update_cpu_load(struct rq
*this_rq
);
695 static void set_load_weight(struct task_struct
*p
)
697 int prio
= p
->static_prio
- MAX_RT_PRIO
;
698 struct load_weight
*load
= &p
->se
.load
;
701 * SCHED_IDLE tasks get minimal weight:
703 if (p
->policy
== SCHED_IDLE
) {
704 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
705 load
->inv_weight
= WMULT_IDLEPRIO
;
709 load
->weight
= scale_load(prio_to_weight
[prio
]);
710 load
->inv_weight
= prio_to_wmult
[prio
];
713 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
716 sched_info_queued(p
);
717 p
->sched_class
->enqueue_task(rq
, p
, flags
);
720 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
723 sched_info_dequeued(p
);
724 p
->sched_class
->dequeue_task(rq
, p
, flags
);
727 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
729 if (task_contributes_to_load(p
))
730 rq
->nr_uninterruptible
--;
732 enqueue_task(rq
, p
, flags
);
735 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
737 if (task_contributes_to_load(p
))
738 rq
->nr_uninterruptible
++;
740 dequeue_task(rq
, p
, flags
);
743 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
746 * There are no locks covering percpu hardirq/softirq time.
747 * They are only modified in account_system_vtime, on corresponding CPU
748 * with interrupts disabled. So, writes are safe.
749 * They are read and saved off onto struct rq in update_rq_clock().
750 * This may result in other CPU reading this CPU's irq time and can
751 * race with irq/account_system_vtime on this CPU. We would either get old
752 * or new value with a side effect of accounting a slice of irq time to wrong
753 * task when irq is in progress while we read rq->clock. That is a worthy
754 * compromise in place of having locks on each irq in account_system_time.
756 static DEFINE_PER_CPU(u64
, cpu_hardirq_time
);
757 static DEFINE_PER_CPU(u64
, cpu_softirq_time
);
759 static DEFINE_PER_CPU(u64
, irq_start_time
);
760 static int sched_clock_irqtime
;
762 void enable_sched_clock_irqtime(void)
764 sched_clock_irqtime
= 1;
767 void disable_sched_clock_irqtime(void)
769 sched_clock_irqtime
= 0;
773 static DEFINE_PER_CPU(seqcount_t
, irq_time_seq
);
775 static inline void irq_time_write_begin(void)
777 __this_cpu_inc(irq_time_seq
.sequence
);
781 static inline void irq_time_write_end(void)
784 __this_cpu_inc(irq_time_seq
.sequence
);
787 static inline u64
irq_time_read(int cpu
)
793 seq
= read_seqcount_begin(&per_cpu(irq_time_seq
, cpu
));
794 irq_time
= per_cpu(cpu_softirq_time
, cpu
) +
795 per_cpu(cpu_hardirq_time
, cpu
);
796 } while (read_seqcount_retry(&per_cpu(irq_time_seq
, cpu
), seq
));
800 #else /* CONFIG_64BIT */
801 static inline void irq_time_write_begin(void)
805 static inline void irq_time_write_end(void)
809 static inline u64
irq_time_read(int cpu
)
811 return per_cpu(cpu_softirq_time
, cpu
) + per_cpu(cpu_hardirq_time
, cpu
);
813 #endif /* CONFIG_64BIT */
816 * Called before incrementing preempt_count on {soft,}irq_enter
817 * and before decrementing preempt_count on {soft,}irq_exit.
819 void account_system_vtime(struct task_struct
*curr
)
825 if (!sched_clock_irqtime
)
828 local_irq_save(flags
);
830 cpu
= smp_processor_id();
831 delta
= sched_clock_cpu(cpu
) - __this_cpu_read(irq_start_time
);
832 __this_cpu_add(irq_start_time
, delta
);
834 irq_time_write_begin();
836 * We do not account for softirq time from ksoftirqd here.
837 * We want to continue accounting softirq time to ksoftirqd thread
838 * in that case, so as not to confuse scheduler with a special task
839 * that do not consume any time, but still wants to run.
842 __this_cpu_add(cpu_hardirq_time
, delta
);
843 else if (in_serving_softirq() && curr
!= this_cpu_ksoftirqd())
844 __this_cpu_add(cpu_softirq_time
, delta
);
846 irq_time_write_end();
847 local_irq_restore(flags
);
849 EXPORT_SYMBOL_GPL(account_system_vtime
);
851 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
853 #ifdef CONFIG_PARAVIRT
854 static inline u64
steal_ticks(u64 steal
)
856 if (unlikely(steal
> NSEC_PER_SEC
))
857 return div_u64(steal
, TICK_NSEC
);
859 return __iter_div_u64_rem(steal
, TICK_NSEC
, &steal
);
863 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
866 * In theory, the compile should just see 0 here, and optimize out the call
867 * to sched_rt_avg_update. But I don't trust it...
869 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
870 s64 steal
= 0, irq_delta
= 0;
872 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
873 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
876 * Since irq_time is only updated on {soft,}irq_exit, we might run into
877 * this case when a previous update_rq_clock() happened inside a
880 * When this happens, we stop ->clock_task and only update the
881 * prev_irq_time stamp to account for the part that fit, so that a next
882 * update will consume the rest. This ensures ->clock_task is
885 * It does however cause some slight miss-attribution of {soft,}irq
886 * time, a more accurate solution would be to update the irq_time using
887 * the current rq->clock timestamp, except that would require using
890 if (irq_delta
> delta
)
893 rq
->prev_irq_time
+= irq_delta
;
896 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
897 if (static_branch((¶virt_steal_rq_enabled
))) {
900 steal
= paravirt_steal_clock(cpu_of(rq
));
901 steal
-= rq
->prev_steal_time_rq
;
903 if (unlikely(steal
> delta
))
906 st
= steal_ticks(steal
);
907 steal
= st
* TICK_NSEC
;
909 rq
->prev_steal_time_rq
+= steal
;
915 rq
->clock_task
+= delta
;
917 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
918 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
919 sched_rt_avg_update(rq
, irq_delta
+ steal
);
923 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
924 static int irqtime_account_hi_update(void)
926 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
931 local_irq_save(flags
);
932 latest_ns
= this_cpu_read(cpu_hardirq_time
);
933 if (nsecs_to_cputime64(latest_ns
) > cpustat
[CPUTIME_IRQ
])
935 local_irq_restore(flags
);
939 static int irqtime_account_si_update(void)
941 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
946 local_irq_save(flags
);
947 latest_ns
= this_cpu_read(cpu_softirq_time
);
948 if (nsecs_to_cputime64(latest_ns
) > cpustat
[CPUTIME_SOFTIRQ
])
950 local_irq_restore(flags
);
954 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
956 #define sched_clock_irqtime (0)
960 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
962 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
963 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
967 * Make it appear like a SCHED_FIFO task, its something
968 * userspace knows about and won't get confused about.
970 * Also, it will make PI more or less work without too
971 * much confusion -- but then, stop work should not
972 * rely on PI working anyway.
974 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
976 stop
->sched_class
= &stop_sched_class
;
979 cpu_rq(cpu
)->stop
= stop
;
983 * Reset it back to a normal scheduling class so that
984 * it can die in pieces.
986 old_stop
->sched_class
= &rt_sched_class
;
991 * __normal_prio - return the priority that is based on the static prio
993 static inline int __normal_prio(struct task_struct
*p
)
995 return p
->static_prio
;
999 * Calculate the expected normal priority: i.e. priority
1000 * without taking RT-inheritance into account. Might be
1001 * boosted by interactivity modifiers. Changes upon fork,
1002 * setprio syscalls, and whenever the interactivity
1003 * estimator recalculates.
1005 static inline int normal_prio(struct task_struct
*p
)
1009 if (task_has_rt_policy(p
))
1010 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1012 prio
= __normal_prio(p
);
1017 * Calculate the current priority, i.e. the priority
1018 * taken into account by the scheduler. This value might
1019 * be boosted by RT tasks, or might be boosted by
1020 * interactivity modifiers. Will be RT if the task got
1021 * RT-boosted. If not then it returns p->normal_prio.
1023 static int effective_prio(struct task_struct
*p
)
1025 p
->normal_prio
= normal_prio(p
);
1027 * If we are RT tasks or we were boosted to RT priority,
1028 * keep the priority unchanged. Otherwise, update priority
1029 * to the normal priority:
1031 if (!rt_prio(p
->prio
))
1032 return p
->normal_prio
;
1037 * task_curr - is this task currently executing on a CPU?
1038 * @p: the task in question.
1040 inline int task_curr(const struct task_struct
*p
)
1042 return cpu_curr(task_cpu(p
)) == p
;
1045 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1046 const struct sched_class
*prev_class
,
1049 if (prev_class
!= p
->sched_class
) {
1050 if (prev_class
->switched_from
)
1051 prev_class
->switched_from(rq
, p
);
1052 p
->sched_class
->switched_to(rq
, p
);
1053 } else if (oldprio
!= p
->prio
)
1054 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
1057 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
1059 const struct sched_class
*class;
1061 if (p
->sched_class
== rq
->curr
->sched_class
) {
1062 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
1064 for_each_class(class) {
1065 if (class == rq
->curr
->sched_class
)
1067 if (class == p
->sched_class
) {
1068 resched_task(rq
->curr
);
1075 * A queue event has occurred, and we're going to schedule. In
1076 * this case, we can save a useless back to back clock update.
1078 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
1079 rq
->skip_clock_update
= 1;
1083 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1085 #ifdef CONFIG_SCHED_DEBUG
1087 * We should never call set_task_cpu() on a blocked task,
1088 * ttwu() will sort out the placement.
1090 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
1091 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
1093 #ifdef CONFIG_LOCKDEP
1095 * The caller should hold either p->pi_lock or rq->lock, when changing
1096 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1098 * sched_move_task() holds both and thus holding either pins the cgroup,
1099 * see set_task_rq().
1101 * Furthermore, all task_rq users should acquire both locks, see
1104 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1105 lockdep_is_held(&task_rq(p
)->lock
)));
1109 trace_sched_migrate_task(p
, new_cpu
);
1111 if (task_cpu(p
) != new_cpu
) {
1112 p
->se
.nr_migrations
++;
1113 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1116 __set_task_cpu(p
, new_cpu
);
1119 struct migration_arg
{
1120 struct task_struct
*task
;
1124 static int migration_cpu_stop(void *data
);
1127 * wait_task_inactive - wait for a thread to unschedule.
1129 * If @match_state is nonzero, it's the @p->state value just checked and
1130 * not expected to change. If it changes, i.e. @p might have woken up,
1131 * then return zero. When we succeed in waiting for @p to be off its CPU,
1132 * we return a positive number (its total switch count). If a second call
1133 * a short while later returns the same number, the caller can be sure that
1134 * @p has remained unscheduled the whole time.
1136 * The caller must ensure that the task *will* unschedule sometime soon,
1137 * else this function might spin for a *long* time. This function can't
1138 * be called with interrupts off, or it may introduce deadlock with
1139 * smp_call_function() if an IPI is sent by the same process we are
1140 * waiting to become inactive.
1142 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1144 unsigned long flags
;
1151 * We do the initial early heuristics without holding
1152 * any task-queue locks at all. We'll only try to get
1153 * the runqueue lock when things look like they will
1159 * If the task is actively running on another CPU
1160 * still, just relax and busy-wait without holding
1163 * NOTE! Since we don't hold any locks, it's not
1164 * even sure that "rq" stays as the right runqueue!
1165 * But we don't care, since "task_running()" will
1166 * return false if the runqueue has changed and p
1167 * is actually now running somewhere else!
1169 while (task_running(rq
, p
)) {
1170 if (match_state
&& unlikely(p
->state
!= match_state
))
1176 * Ok, time to look more closely! We need the rq
1177 * lock now, to be *sure*. If we're wrong, we'll
1178 * just go back and repeat.
1180 rq
= task_rq_lock(p
, &flags
);
1181 trace_sched_wait_task(p
);
1182 running
= task_running(rq
, p
);
1185 if (!match_state
|| p
->state
== match_state
)
1186 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1187 task_rq_unlock(rq
, p
, &flags
);
1190 * If it changed from the expected state, bail out now.
1192 if (unlikely(!ncsw
))
1196 * Was it really running after all now that we
1197 * checked with the proper locks actually held?
1199 * Oops. Go back and try again..
1201 if (unlikely(running
)) {
1207 * It's not enough that it's not actively running,
1208 * it must be off the runqueue _entirely_, and not
1211 * So if it was still runnable (but just not actively
1212 * running right now), it's preempted, and we should
1213 * yield - it could be a while.
1215 if (unlikely(on_rq
)) {
1216 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1218 set_current_state(TASK_UNINTERRUPTIBLE
);
1219 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1224 * Ahh, all good. It wasn't running, and it wasn't
1225 * runnable, which means that it will never become
1226 * running in the future either. We're all done!
1235 * kick_process - kick a running thread to enter/exit the kernel
1236 * @p: the to-be-kicked thread
1238 * Cause a process which is running on another CPU to enter
1239 * kernel-mode, without any delay. (to get signals handled.)
1241 * NOTE: this function doesn't have to take the runqueue lock,
1242 * because all it wants to ensure is that the remote task enters
1243 * the kernel. If the IPI races and the task has been migrated
1244 * to another CPU then no harm is done and the purpose has been
1247 void kick_process(struct task_struct
*p
)
1253 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1254 smp_send_reschedule(cpu
);
1257 EXPORT_SYMBOL_GPL(kick_process
);
1258 #endif /* CONFIG_SMP */
1262 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1264 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1267 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
1269 /* Look for allowed, online CPU in same node. */
1270 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
1271 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1274 /* Any allowed, online CPU? */
1275 dest_cpu
= cpumask_any_and(tsk_cpus_allowed(p
), cpu_active_mask
);
1276 if (dest_cpu
< nr_cpu_ids
)
1279 /* No more Mr. Nice Guy. */
1280 dest_cpu
= cpuset_cpus_allowed_fallback(p
);
1282 * Don't tell them about moving exiting tasks or
1283 * kernel threads (both mm NULL), since they never
1286 if (p
->mm
&& printk_ratelimit()) {
1287 printk(KERN_INFO
"process %d (%s) no longer affine to cpu%d\n",
1288 task_pid_nr(p
), p
->comm
, cpu
);
1295 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1298 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
1300 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
1303 * In order not to call set_task_cpu() on a blocking task we need
1304 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1307 * Since this is common to all placement strategies, this lives here.
1309 * [ this allows ->select_task() to simply return task_cpu(p) and
1310 * not worry about this generic constraint ]
1312 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1314 cpu
= select_fallback_rq(task_cpu(p
), p
);
1319 static void update_avg(u64
*avg
, u64 sample
)
1321 s64 diff
= sample
- *avg
;
1327 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1329 #ifdef CONFIG_SCHEDSTATS
1330 struct rq
*rq
= this_rq();
1333 int this_cpu
= smp_processor_id();
1335 if (cpu
== this_cpu
) {
1336 schedstat_inc(rq
, ttwu_local
);
1337 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1339 struct sched_domain
*sd
;
1341 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1343 for_each_domain(this_cpu
, sd
) {
1344 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1345 schedstat_inc(sd
, ttwu_wake_remote
);
1352 if (wake_flags
& WF_MIGRATED
)
1353 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1355 #endif /* CONFIG_SMP */
1357 schedstat_inc(rq
, ttwu_count
);
1358 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1360 if (wake_flags
& WF_SYNC
)
1361 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1363 #endif /* CONFIG_SCHEDSTATS */
1366 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1368 activate_task(rq
, p
, en_flags
);
1371 /* if a worker is waking up, notify workqueue */
1372 if (p
->flags
& PF_WQ_WORKER
)
1373 wq_worker_waking_up(p
, cpu_of(rq
));
1377 * Mark the task runnable and perform wakeup-preemption.
1380 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1382 trace_sched_wakeup(p
, true);
1383 check_preempt_curr(rq
, p
, wake_flags
);
1385 p
->state
= TASK_RUNNING
;
1387 if (p
->sched_class
->task_woken
)
1388 p
->sched_class
->task_woken(rq
, p
);
1390 if (rq
->idle_stamp
) {
1391 u64 delta
= rq
->clock
- rq
->idle_stamp
;
1392 u64 max
= 2*sysctl_sched_migration_cost
;
1397 update_avg(&rq
->avg_idle
, delta
);
1404 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1407 if (p
->sched_contributes_to_load
)
1408 rq
->nr_uninterruptible
--;
1411 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1412 ttwu_do_wakeup(rq
, p
, wake_flags
);
1416 * Called in case the task @p isn't fully descheduled from its runqueue,
1417 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1418 * since all we need to do is flip p->state to TASK_RUNNING, since
1419 * the task is still ->on_rq.
1421 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1426 rq
= __task_rq_lock(p
);
1428 ttwu_do_wakeup(rq
, p
, wake_flags
);
1431 __task_rq_unlock(rq
);
1437 static void sched_ttwu_pending(void)
1439 struct rq
*rq
= this_rq();
1440 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1441 struct task_struct
*p
;
1443 raw_spin_lock(&rq
->lock
);
1446 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1447 llist
= llist_next(llist
);
1448 ttwu_do_activate(rq
, p
, 0);
1451 raw_spin_unlock(&rq
->lock
);
1454 void scheduler_ipi(void)
1456 if (llist_empty(&this_rq()->wake_list
) && !got_nohz_idle_kick())
1460 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1461 * traditionally all their work was done from the interrupt return
1462 * path. Now that we actually do some work, we need to make sure
1465 * Some archs already do call them, luckily irq_enter/exit nest
1468 * Arguably we should visit all archs and update all handlers,
1469 * however a fair share of IPIs are still resched only so this would
1470 * somewhat pessimize the simple resched case.
1473 sched_ttwu_pending();
1476 * Check if someone kicked us for doing the nohz idle load balance.
1478 if (unlikely(got_nohz_idle_kick() && !need_resched())) {
1479 this_rq()->idle_balance
= 1;
1480 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1485 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1487 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
1488 smp_send_reschedule(cpu
);
1491 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1492 static int ttwu_activate_remote(struct task_struct
*p
, int wake_flags
)
1497 rq
= __task_rq_lock(p
);
1499 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1500 ttwu_do_wakeup(rq
, p
, wake_flags
);
1503 __task_rq_unlock(rq
);
1508 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1510 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1512 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1514 #endif /* CONFIG_SMP */
1516 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1518 struct rq
*rq
= cpu_rq(cpu
);
1520 #if defined(CONFIG_SMP)
1521 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1522 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1523 ttwu_queue_remote(p
, cpu
);
1528 raw_spin_lock(&rq
->lock
);
1529 ttwu_do_activate(rq
, p
, 0);
1530 raw_spin_unlock(&rq
->lock
);
1534 * try_to_wake_up - wake up a thread
1535 * @p: the thread to be awakened
1536 * @state: the mask of task states that can be woken
1537 * @wake_flags: wake modifier flags (WF_*)
1539 * Put it on the run-queue if it's not already there. The "current"
1540 * thread is always on the run-queue (except when the actual
1541 * re-schedule is in progress), and as such you're allowed to do
1542 * the simpler "current->state = TASK_RUNNING" to mark yourself
1543 * runnable without the overhead of this.
1545 * Returns %true if @p was woken up, %false if it was already running
1546 * or @state didn't match @p's state.
1549 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1551 unsigned long flags
;
1552 int cpu
, success
= 0;
1555 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1556 if (!(p
->state
& state
))
1559 success
= 1; /* we're going to change ->state */
1562 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1567 * If the owning (remote) cpu is still in the middle of schedule() with
1568 * this task as prev, wait until its done referencing the task.
1571 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1573 * In case the architecture enables interrupts in
1574 * context_switch(), we cannot busy wait, since that
1575 * would lead to deadlocks when an interrupt hits and
1576 * tries to wake up @prev. So bail and do a complete
1579 if (ttwu_activate_remote(p
, wake_flags
))
1586 * Pairs with the smp_wmb() in finish_lock_switch().
1590 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1591 p
->state
= TASK_WAKING
;
1593 if (p
->sched_class
->task_waking
)
1594 p
->sched_class
->task_waking(p
);
1596 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
1597 if (task_cpu(p
) != cpu
) {
1598 wake_flags
|= WF_MIGRATED
;
1599 set_task_cpu(p
, cpu
);
1601 #endif /* CONFIG_SMP */
1605 ttwu_stat(p
, cpu
, wake_flags
);
1607 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1613 * try_to_wake_up_local - try to wake up a local task with rq lock held
1614 * @p: the thread to be awakened
1616 * Put @p on the run-queue if it's not already there. The caller must
1617 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1620 static void try_to_wake_up_local(struct task_struct
*p
)
1622 struct rq
*rq
= task_rq(p
);
1624 BUG_ON(rq
!= this_rq());
1625 BUG_ON(p
== current
);
1626 lockdep_assert_held(&rq
->lock
);
1628 if (!raw_spin_trylock(&p
->pi_lock
)) {
1629 raw_spin_unlock(&rq
->lock
);
1630 raw_spin_lock(&p
->pi_lock
);
1631 raw_spin_lock(&rq
->lock
);
1634 if (!(p
->state
& TASK_NORMAL
))
1638 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1640 ttwu_do_wakeup(rq
, p
, 0);
1641 ttwu_stat(p
, smp_processor_id(), 0);
1643 raw_spin_unlock(&p
->pi_lock
);
1647 * wake_up_process - Wake up a specific process
1648 * @p: The process to be woken up.
1650 * Attempt to wake up the nominated process and move it to the set of runnable
1651 * processes. Returns 1 if the process was woken up, 0 if it was already
1654 * It may be assumed that this function implies a write memory barrier before
1655 * changing the task state if and only if any tasks are woken up.
1657 int wake_up_process(struct task_struct
*p
)
1659 return try_to_wake_up(p
, TASK_ALL
, 0);
1661 EXPORT_SYMBOL(wake_up_process
);
1663 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1665 return try_to_wake_up(p
, state
, 0);
1669 * Perform scheduler related setup for a newly forked process p.
1670 * p is forked by current.
1672 * __sched_fork() is basic setup used by init_idle() too:
1674 static void __sched_fork(struct task_struct
*p
)
1679 p
->se
.exec_start
= 0;
1680 p
->se
.sum_exec_runtime
= 0;
1681 p
->se
.prev_sum_exec_runtime
= 0;
1682 p
->se
.nr_migrations
= 0;
1684 INIT_LIST_HEAD(&p
->se
.group_node
);
1686 #ifdef CONFIG_SCHEDSTATS
1687 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1690 INIT_LIST_HEAD(&p
->rt
.run_list
);
1692 #ifdef CONFIG_PREEMPT_NOTIFIERS
1693 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1698 * fork()/clone()-time setup:
1700 void sched_fork(struct task_struct
*p
)
1702 unsigned long flags
;
1703 int cpu
= get_cpu();
1707 * We mark the process as running here. This guarantees that
1708 * nobody will actually run it, and a signal or other external
1709 * event cannot wake it up and insert it on the runqueue either.
1711 p
->state
= TASK_RUNNING
;
1714 * Make sure we do not leak PI boosting priority to the child.
1716 p
->prio
= current
->normal_prio
;
1719 * Revert to default priority/policy on fork if requested.
1721 if (unlikely(p
->sched_reset_on_fork
)) {
1722 if (task_has_rt_policy(p
)) {
1723 p
->policy
= SCHED_NORMAL
;
1724 p
->static_prio
= NICE_TO_PRIO(0);
1726 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1727 p
->static_prio
= NICE_TO_PRIO(0);
1729 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1733 * We don't need the reset flag anymore after the fork. It has
1734 * fulfilled its duty:
1736 p
->sched_reset_on_fork
= 0;
1739 if (!rt_prio(p
->prio
))
1740 p
->sched_class
= &fair_sched_class
;
1742 if (p
->sched_class
->task_fork
)
1743 p
->sched_class
->task_fork(p
);
1746 * The child is not yet in the pid-hash so no cgroup attach races,
1747 * and the cgroup is pinned to this child due to cgroup_fork()
1748 * is ran before sched_fork().
1750 * Silence PROVE_RCU.
1752 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1753 set_task_cpu(p
, cpu
);
1754 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1756 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1757 if (likely(sched_info_on()))
1758 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1760 #if defined(CONFIG_SMP)
1763 #ifdef CONFIG_PREEMPT_COUNT
1764 /* Want to start with kernel preemption disabled. */
1765 task_thread_info(p
)->preempt_count
= 1;
1768 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1775 * wake_up_new_task - wake up a newly created task for the first time.
1777 * This function will do some initial scheduler statistics housekeeping
1778 * that must be done for every newly created context, then puts the task
1779 * on the runqueue and wakes it.
1781 void wake_up_new_task(struct task_struct
*p
)
1783 unsigned long flags
;
1786 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1789 * Fork balancing, do it here and not earlier because:
1790 * - cpus_allowed can change in the fork path
1791 * - any previously selected cpu might disappear through hotplug
1793 set_task_cpu(p
, select_task_rq(p
, SD_BALANCE_FORK
, 0));
1796 rq
= __task_rq_lock(p
);
1797 activate_task(rq
, p
, 0);
1799 trace_sched_wakeup_new(p
, true);
1800 check_preempt_curr(rq
, p
, WF_FORK
);
1802 if (p
->sched_class
->task_woken
)
1803 p
->sched_class
->task_woken(rq
, p
);
1805 task_rq_unlock(rq
, p
, &flags
);
1808 #ifdef CONFIG_PREEMPT_NOTIFIERS
1811 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1812 * @notifier: notifier struct to register
1814 void preempt_notifier_register(struct preempt_notifier
*notifier
)
1816 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
1818 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
1821 * preempt_notifier_unregister - no longer interested in preemption notifications
1822 * @notifier: notifier struct to unregister
1824 * This is safe to call from within a preemption notifier.
1826 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
1828 hlist_del(¬ifier
->link
);
1830 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
1832 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1834 struct preempt_notifier
*notifier
;
1835 struct hlist_node
*node
;
1837 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
1838 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
1842 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1843 struct task_struct
*next
)
1845 struct preempt_notifier
*notifier
;
1846 struct hlist_node
*node
;
1848 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
1849 notifier
->ops
->sched_out(notifier
, next
);
1852 #else /* !CONFIG_PREEMPT_NOTIFIERS */
1854 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1859 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1860 struct task_struct
*next
)
1864 #endif /* CONFIG_PREEMPT_NOTIFIERS */
1867 * prepare_task_switch - prepare to switch tasks
1868 * @rq: the runqueue preparing to switch
1869 * @prev: the current task that is being switched out
1870 * @next: the task we are going to switch to.
1872 * This is called with the rq lock held and interrupts off. It must
1873 * be paired with a subsequent finish_task_switch after the context
1876 * prepare_task_switch sets up locking and calls architecture specific
1880 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
1881 struct task_struct
*next
)
1883 sched_info_switch(prev
, next
);
1884 perf_event_task_sched_out(prev
, next
);
1885 fire_sched_out_preempt_notifiers(prev
, next
);
1886 prepare_lock_switch(rq
, next
);
1887 prepare_arch_switch(next
);
1888 trace_sched_switch(prev
, next
);
1892 * finish_task_switch - clean up after a task-switch
1893 * @rq: runqueue associated with task-switch
1894 * @prev: the thread we just switched away from.
1896 * finish_task_switch must be called after the context switch, paired
1897 * with a prepare_task_switch call before the context switch.
1898 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1899 * and do any other architecture-specific cleanup actions.
1901 * Note that we may have delayed dropping an mm in context_switch(). If
1902 * so, we finish that here outside of the runqueue lock. (Doing it
1903 * with the lock held can cause deadlocks; see schedule() for
1906 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
1907 __releases(rq
->lock
)
1909 struct mm_struct
*mm
= rq
->prev_mm
;
1915 * A task struct has one reference for the use as "current".
1916 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1917 * schedule one last time. The schedule call will never return, and
1918 * the scheduled task must drop that reference.
1919 * The test for TASK_DEAD must occur while the runqueue locks are
1920 * still held, otherwise prev could be scheduled on another cpu, die
1921 * there before we look at prev->state, and then the reference would
1923 * Manfred Spraul <manfred@colorfullife.com>
1925 prev_state
= prev
->state
;
1926 finish_arch_switch(prev
);
1927 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1928 local_irq_disable();
1929 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1930 perf_event_task_sched_in(prev
, current
);
1931 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1933 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1934 finish_lock_switch(rq
, prev
);
1935 trace_sched_stat_sleeptime(current
, rq
->clock
);
1937 fire_sched_in_preempt_notifiers(current
);
1940 if (unlikely(prev_state
== TASK_DEAD
)) {
1942 * Remove function-return probe instances associated with this
1943 * task and put them back on the free list.
1945 kprobe_flush_task(prev
);
1946 put_task_struct(prev
);
1952 /* assumes rq->lock is held */
1953 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
1955 if (prev
->sched_class
->pre_schedule
)
1956 prev
->sched_class
->pre_schedule(rq
, prev
);
1959 /* rq->lock is NOT held, but preemption is disabled */
1960 static inline void post_schedule(struct rq
*rq
)
1962 if (rq
->post_schedule
) {
1963 unsigned long flags
;
1965 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1966 if (rq
->curr
->sched_class
->post_schedule
)
1967 rq
->curr
->sched_class
->post_schedule(rq
);
1968 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1970 rq
->post_schedule
= 0;
1976 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
1980 static inline void post_schedule(struct rq
*rq
)
1987 * schedule_tail - first thing a freshly forked thread must call.
1988 * @prev: the thread we just switched away from.
1990 asmlinkage
void schedule_tail(struct task_struct
*prev
)
1991 __releases(rq
->lock
)
1993 struct rq
*rq
= this_rq();
1995 finish_task_switch(rq
, prev
);
1998 * FIXME: do we need to worry about rq being invalidated by the
2003 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2004 /* In this case, finish_task_switch does not reenable preemption */
2007 if (current
->set_child_tid
)
2008 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2012 * context_switch - switch to the new MM and the new
2013 * thread's register state.
2016 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2017 struct task_struct
*next
)
2019 struct mm_struct
*mm
, *oldmm
;
2021 prepare_task_switch(rq
, prev
, next
);
2024 oldmm
= prev
->active_mm
;
2026 * For paravirt, this is coupled with an exit in switch_to to
2027 * combine the page table reload and the switch backend into
2030 arch_start_context_switch(prev
);
2033 next
->active_mm
= oldmm
;
2034 atomic_inc(&oldmm
->mm_count
);
2035 enter_lazy_tlb(oldmm
, next
);
2037 switch_mm(oldmm
, mm
, next
);
2040 prev
->active_mm
= NULL
;
2041 rq
->prev_mm
= oldmm
;
2044 * Since the runqueue lock will be released by the next
2045 * task (which is an invalid locking op but in the case
2046 * of the scheduler it's an obvious special-case), so we
2047 * do an early lockdep release here:
2049 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2050 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2053 /* Here we just switch the register state and the stack. */
2054 switch_to(prev
, next
, prev
);
2058 * this_rq must be evaluated again because prev may have moved
2059 * CPUs since it called schedule(), thus the 'rq' on its stack
2060 * frame will be invalid.
2062 finish_task_switch(this_rq(), prev
);
2066 * nr_running, nr_uninterruptible and nr_context_switches:
2068 * externally visible scheduler statistics: current number of runnable
2069 * threads, current number of uninterruptible-sleeping threads, total
2070 * number of context switches performed since bootup.
2072 unsigned long nr_running(void)
2074 unsigned long i
, sum
= 0;
2076 for_each_online_cpu(i
)
2077 sum
+= cpu_rq(i
)->nr_running
;
2082 unsigned long nr_uninterruptible(void)
2084 unsigned long i
, sum
= 0;
2086 for_each_possible_cpu(i
)
2087 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2090 * Since we read the counters lockless, it might be slightly
2091 * inaccurate. Do not allow it to go below zero though:
2093 if (unlikely((long)sum
< 0))
2099 unsigned long long nr_context_switches(void)
2102 unsigned long long sum
= 0;
2104 for_each_possible_cpu(i
)
2105 sum
+= cpu_rq(i
)->nr_switches
;
2110 unsigned long nr_iowait(void)
2112 unsigned long i
, sum
= 0;
2114 for_each_possible_cpu(i
)
2115 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2120 unsigned long nr_iowait_cpu(int cpu
)
2122 struct rq
*this = cpu_rq(cpu
);
2123 return atomic_read(&this->nr_iowait
);
2126 unsigned long this_cpu_load(void)
2128 struct rq
*this = this_rq();
2129 return this->cpu_load
[0];
2133 /* Variables and functions for calc_load */
2134 static atomic_long_t calc_load_tasks
;
2135 static unsigned long calc_load_update
;
2136 unsigned long avenrun
[3];
2137 EXPORT_SYMBOL(avenrun
);
2139 static long calc_load_fold_active(struct rq
*this_rq
)
2141 long nr_active
, delta
= 0;
2143 nr_active
= this_rq
->nr_running
;
2144 nr_active
+= (long) this_rq
->nr_uninterruptible
;
2146 if (nr_active
!= this_rq
->calc_load_active
) {
2147 delta
= nr_active
- this_rq
->calc_load_active
;
2148 this_rq
->calc_load_active
= nr_active
;
2154 static unsigned long
2155 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
2158 load
+= active
* (FIXED_1
- exp
);
2159 load
+= 1UL << (FSHIFT
- 1);
2160 return load
>> FSHIFT
;
2165 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
2167 * When making the ILB scale, we should try to pull this in as well.
2169 static atomic_long_t calc_load_tasks_idle
;
2171 void calc_load_account_idle(struct rq
*this_rq
)
2175 delta
= calc_load_fold_active(this_rq
);
2177 atomic_long_add(delta
, &calc_load_tasks_idle
);
2180 static long calc_load_fold_idle(void)
2185 * Its got a race, we don't care...
2187 if (atomic_long_read(&calc_load_tasks_idle
))
2188 delta
= atomic_long_xchg(&calc_load_tasks_idle
, 0);
2194 * fixed_power_int - compute: x^n, in O(log n) time
2196 * @x: base of the power
2197 * @frac_bits: fractional bits of @x
2198 * @n: power to raise @x to.
2200 * By exploiting the relation between the definition of the natural power
2201 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
2202 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
2203 * (where: n_i \elem {0, 1}, the binary vector representing n),
2204 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
2205 * of course trivially computable in O(log_2 n), the length of our binary
2208 static unsigned long
2209 fixed_power_int(unsigned long x
, unsigned int frac_bits
, unsigned int n
)
2211 unsigned long result
= 1UL << frac_bits
;
2216 result
+= 1UL << (frac_bits
- 1);
2217 result
>>= frac_bits
;
2223 x
+= 1UL << (frac_bits
- 1);
2231 * a1 = a0 * e + a * (1 - e)
2233 * a2 = a1 * e + a * (1 - e)
2234 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
2235 * = a0 * e^2 + a * (1 - e) * (1 + e)
2237 * a3 = a2 * e + a * (1 - e)
2238 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
2239 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
2243 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
2244 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
2245 * = a0 * e^n + a * (1 - e^n)
2247 * [1] application of the geometric series:
2250 * S_n := \Sum x^i = -------------
2253 static unsigned long
2254 calc_load_n(unsigned long load
, unsigned long exp
,
2255 unsigned long active
, unsigned int n
)
2258 return calc_load(load
, fixed_power_int(exp
, FSHIFT
, n
), active
);
2262 * NO_HZ can leave us missing all per-cpu ticks calling
2263 * calc_load_account_active(), but since an idle CPU folds its delta into
2264 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
2265 * in the pending idle delta if our idle period crossed a load cycle boundary.
2267 * Once we've updated the global active value, we need to apply the exponential
2268 * weights adjusted to the number of cycles missed.
2270 static void calc_global_nohz(unsigned long ticks
)
2272 long delta
, active
, n
;
2274 if (time_before(jiffies
, calc_load_update
))
2278 * If we crossed a calc_load_update boundary, make sure to fold
2279 * any pending idle changes, the respective CPUs might have
2280 * missed the tick driven calc_load_account_active() update
2283 delta
= calc_load_fold_idle();
2285 atomic_long_add(delta
, &calc_load_tasks
);
2288 * If we were idle for multiple load cycles, apply them.
2290 if (ticks
>= LOAD_FREQ
) {
2291 n
= ticks
/ LOAD_FREQ
;
2293 active
= atomic_long_read(&calc_load_tasks
);
2294 active
= active
> 0 ? active
* FIXED_1
: 0;
2296 avenrun
[0] = calc_load_n(avenrun
[0], EXP_1
, active
, n
);
2297 avenrun
[1] = calc_load_n(avenrun
[1], EXP_5
, active
, n
);
2298 avenrun
[2] = calc_load_n(avenrun
[2], EXP_15
, active
, n
);
2300 calc_load_update
+= n
* LOAD_FREQ
;
2304 * Its possible the remainder of the above division also crosses
2305 * a LOAD_FREQ period, the regular check in calc_global_load()
2306 * which comes after this will take care of that.
2308 * Consider us being 11 ticks before a cycle completion, and us
2309 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
2310 * age us 4 cycles, and the test in calc_global_load() will
2311 * pick up the final one.
2315 void calc_load_account_idle(struct rq
*this_rq
)
2319 static inline long calc_load_fold_idle(void)
2324 static void calc_global_nohz(unsigned long ticks
)
2330 * get_avenrun - get the load average array
2331 * @loads: pointer to dest load array
2332 * @offset: offset to add
2333 * @shift: shift count to shift the result left
2335 * These values are estimates at best, so no need for locking.
2337 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
2339 loads
[0] = (avenrun
[0] + offset
) << shift
;
2340 loads
[1] = (avenrun
[1] + offset
) << shift
;
2341 loads
[2] = (avenrun
[2] + offset
) << shift
;
2345 * calc_load - update the avenrun load estimates 10 ticks after the
2346 * CPUs have updated calc_load_tasks.
2348 void calc_global_load(unsigned long ticks
)
2352 calc_global_nohz(ticks
);
2354 if (time_before(jiffies
, calc_load_update
+ 10))
2357 active
= atomic_long_read(&calc_load_tasks
);
2358 active
= active
> 0 ? active
* FIXED_1
: 0;
2360 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
2361 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
2362 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
2364 calc_load_update
+= LOAD_FREQ
;
2368 * Called from update_cpu_load() to periodically update this CPU's
2371 static void calc_load_account_active(struct rq
*this_rq
)
2375 if (time_before(jiffies
, this_rq
->calc_load_update
))
2378 delta
= calc_load_fold_active(this_rq
);
2379 delta
+= calc_load_fold_idle();
2381 atomic_long_add(delta
, &calc_load_tasks
);
2383 this_rq
->calc_load_update
+= LOAD_FREQ
;
2387 * The exact cpuload at various idx values, calculated at every tick would be
2388 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
2390 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
2391 * on nth tick when cpu may be busy, then we have:
2392 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2393 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
2395 * decay_load_missed() below does efficient calculation of
2396 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2397 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
2399 * The calculation is approximated on a 128 point scale.
2400 * degrade_zero_ticks is the number of ticks after which load at any
2401 * particular idx is approximated to be zero.
2402 * degrade_factor is a precomputed table, a row for each load idx.
2403 * Each column corresponds to degradation factor for a power of two ticks,
2404 * based on 128 point scale.
2406 * row 2, col 3 (=12) says that the degradation at load idx 2 after
2407 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
2409 * With this power of 2 load factors, we can degrade the load n times
2410 * by looking at 1 bits in n and doing as many mult/shift instead of
2411 * n mult/shifts needed by the exact degradation.
2413 #define DEGRADE_SHIFT 7
2414 static const unsigned char
2415 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
2416 static const unsigned char
2417 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
2418 {0, 0, 0, 0, 0, 0, 0, 0},
2419 {64, 32, 8, 0, 0, 0, 0, 0},
2420 {96, 72, 40, 12, 1, 0, 0},
2421 {112, 98, 75, 43, 15, 1, 0},
2422 {120, 112, 98, 76, 45, 16, 2} };
2425 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
2426 * would be when CPU is idle and so we just decay the old load without
2427 * adding any new load.
2429 static unsigned long
2430 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
2434 if (!missed_updates
)
2437 if (missed_updates
>= degrade_zero_ticks
[idx
])
2441 return load
>> missed_updates
;
2443 while (missed_updates
) {
2444 if (missed_updates
% 2)
2445 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
2447 missed_updates
>>= 1;
2454 * Update rq->cpu_load[] statistics. This function is usually called every
2455 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
2456 * every tick. We fix it up based on jiffies.
2458 void update_cpu_load(struct rq
*this_rq
)
2460 unsigned long this_load
= this_rq
->load
.weight
;
2461 unsigned long curr_jiffies
= jiffies
;
2462 unsigned long pending_updates
;
2465 this_rq
->nr_load_updates
++;
2467 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
2468 if (curr_jiffies
== this_rq
->last_load_update_tick
)
2471 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
2472 this_rq
->last_load_update_tick
= curr_jiffies
;
2474 /* Update our load: */
2475 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
2476 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2477 unsigned long old_load
, new_load
;
2479 /* scale is effectively 1 << i now, and >> i divides by scale */
2481 old_load
= this_rq
->cpu_load
[i
];
2482 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
2483 new_load
= this_load
;
2485 * Round up the averaging division if load is increasing. This
2486 * prevents us from getting stuck on 9 if the load is 10, for
2489 if (new_load
> old_load
)
2490 new_load
+= scale
- 1;
2492 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
2495 sched_avg_update(this_rq
);
2498 static void update_cpu_load_active(struct rq
*this_rq
)
2500 update_cpu_load(this_rq
);
2502 calc_load_account_active(this_rq
);
2508 * sched_exec - execve() is a valuable balancing opportunity, because at
2509 * this point the task has the smallest effective memory and cache footprint.
2511 void sched_exec(void)
2513 struct task_struct
*p
= current
;
2514 unsigned long flags
;
2517 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2518 dest_cpu
= p
->sched_class
->select_task_rq(p
, SD_BALANCE_EXEC
, 0);
2519 if (dest_cpu
== smp_processor_id())
2522 if (likely(cpu_active(dest_cpu
))) {
2523 struct migration_arg arg
= { p
, dest_cpu
};
2525 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2526 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2530 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2535 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2536 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2538 EXPORT_PER_CPU_SYMBOL(kstat
);
2539 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2542 * Return any ns on the sched_clock that have not yet been accounted in
2543 * @p in case that task is currently running.
2545 * Called with task_rq_lock() held on @rq.
2547 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2551 if (task_current(rq
, p
)) {
2552 update_rq_clock(rq
);
2553 ns
= rq
->clock_task
- p
->se
.exec_start
;
2561 unsigned long long task_delta_exec(struct task_struct
*p
)
2563 unsigned long flags
;
2567 rq
= task_rq_lock(p
, &flags
);
2568 ns
= do_task_delta_exec(p
, rq
);
2569 task_rq_unlock(rq
, p
, &flags
);
2575 * Return accounted runtime for the task.
2576 * In case the task is currently running, return the runtime plus current's
2577 * pending runtime that have not been accounted yet.
2579 unsigned long long task_sched_runtime(struct task_struct
*p
)
2581 unsigned long flags
;
2585 rq
= task_rq_lock(p
, &flags
);
2586 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2587 task_rq_unlock(rq
, p
, &flags
);
2592 #ifdef CONFIG_CGROUP_CPUACCT
2593 struct cgroup_subsys cpuacct_subsys
;
2594 struct cpuacct root_cpuacct
;
2597 static inline void task_group_account_field(struct task_struct
*p
, int index
,
2600 #ifdef CONFIG_CGROUP_CPUACCT
2601 struct kernel_cpustat
*kcpustat
;
2605 * Since all updates are sure to touch the root cgroup, we
2606 * get ourselves ahead and touch it first. If the root cgroup
2607 * is the only cgroup, then nothing else should be necessary.
2610 __get_cpu_var(kernel_cpustat
).cpustat
[index
] += tmp
;
2612 #ifdef CONFIG_CGROUP_CPUACCT
2613 if (unlikely(!cpuacct_subsys
.active
))
2618 while (ca
&& (ca
!= &root_cpuacct
)) {
2619 kcpustat
= this_cpu_ptr(ca
->cpustat
);
2620 kcpustat
->cpustat
[index
] += tmp
;
2629 * Account user cpu time to a process.
2630 * @p: the process that the cpu time gets accounted to
2631 * @cputime: the cpu time spent in user space since the last update
2632 * @cputime_scaled: cputime scaled by cpu frequency
2634 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
2635 cputime_t cputime_scaled
)
2639 /* Add user time to process. */
2640 p
->utime
+= cputime
;
2641 p
->utimescaled
+= cputime_scaled
;
2642 account_group_user_time(p
, cputime
);
2644 index
= (TASK_NICE(p
) > 0) ? CPUTIME_NICE
: CPUTIME_USER
;
2646 /* Add user time to cpustat. */
2647 task_group_account_field(p
, index
, (__force u64
) cputime
);
2649 /* Account for user time used */
2650 acct_update_integrals(p
);
2654 * Account guest cpu time to a process.
2655 * @p: the process that the cpu time gets accounted to
2656 * @cputime: the cpu time spent in virtual machine since the last update
2657 * @cputime_scaled: cputime scaled by cpu frequency
2659 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
2660 cputime_t cputime_scaled
)
2662 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
2664 /* Add guest time to process. */
2665 p
->utime
+= cputime
;
2666 p
->utimescaled
+= cputime_scaled
;
2667 account_group_user_time(p
, cputime
);
2668 p
->gtime
+= cputime
;
2670 /* Add guest time to cpustat. */
2671 if (TASK_NICE(p
) > 0) {
2672 cpustat
[CPUTIME_NICE
] += (__force u64
) cputime
;
2673 cpustat
[CPUTIME_GUEST_NICE
] += (__force u64
) cputime
;
2675 cpustat
[CPUTIME_USER
] += (__force u64
) cputime
;
2676 cpustat
[CPUTIME_GUEST
] += (__force u64
) cputime
;
2681 * Account system cpu time to a process and desired cpustat field
2682 * @p: the process that the cpu time gets accounted to
2683 * @cputime: the cpu time spent in kernel space since the last update
2684 * @cputime_scaled: cputime scaled by cpu frequency
2685 * @target_cputime64: pointer to cpustat field that has to be updated
2688 void __account_system_time(struct task_struct
*p
, cputime_t cputime
,
2689 cputime_t cputime_scaled
, int index
)
2691 /* Add system time to process. */
2692 p
->stime
+= cputime
;
2693 p
->stimescaled
+= cputime_scaled
;
2694 account_group_system_time(p
, cputime
);
2696 /* Add system time to cpustat. */
2697 task_group_account_field(p
, index
, (__force u64
) cputime
);
2699 /* Account for system time used */
2700 acct_update_integrals(p
);
2704 * Account system cpu time to a process.
2705 * @p: the process that the cpu time gets accounted to
2706 * @hardirq_offset: the offset to subtract from hardirq_count()
2707 * @cputime: the cpu time spent in kernel space since the last update
2708 * @cputime_scaled: cputime scaled by cpu frequency
2710 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
2711 cputime_t cputime
, cputime_t cputime_scaled
)
2715 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
2716 account_guest_time(p
, cputime
, cputime_scaled
);
2720 if (hardirq_count() - hardirq_offset
)
2721 index
= CPUTIME_IRQ
;
2722 else if (in_serving_softirq())
2723 index
= CPUTIME_SOFTIRQ
;
2725 index
= CPUTIME_SYSTEM
;
2727 __account_system_time(p
, cputime
, cputime_scaled
, index
);
2731 * Account for involuntary wait time.
2732 * @cputime: the cpu time spent in involuntary wait
2734 void account_steal_time(cputime_t cputime
)
2736 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
2738 cpustat
[CPUTIME_STEAL
] += (__force u64
) cputime
;
2742 * Account for idle time.
2743 * @cputime: the cpu time spent in idle wait
2745 void account_idle_time(cputime_t cputime
)
2747 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
2748 struct rq
*rq
= this_rq();
2750 if (atomic_read(&rq
->nr_iowait
) > 0)
2751 cpustat
[CPUTIME_IOWAIT
] += (__force u64
) cputime
;
2753 cpustat
[CPUTIME_IDLE
] += (__force u64
) cputime
;
2756 static __always_inline
bool steal_account_process_tick(void)
2758 #ifdef CONFIG_PARAVIRT
2759 if (static_branch(¶virt_steal_enabled
)) {
2762 steal
= paravirt_steal_clock(smp_processor_id());
2763 steal
-= this_rq()->prev_steal_time
;
2765 st
= steal_ticks(steal
);
2766 this_rq()->prev_steal_time
+= st
* TICK_NSEC
;
2768 account_steal_time(st
);
2775 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
2777 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
2779 * Account a tick to a process and cpustat
2780 * @p: the process that the cpu time gets accounted to
2781 * @user_tick: is the tick from userspace
2782 * @rq: the pointer to rq
2784 * Tick demultiplexing follows the order
2785 * - pending hardirq update
2786 * - pending softirq update
2790 * - check for guest_time
2791 * - else account as system_time
2793 * Check for hardirq is done both for system and user time as there is
2794 * no timer going off while we are on hardirq and hence we may never get an
2795 * opportunity to update it solely in system time.
2796 * p->stime and friends are only updated on system time and not on irq
2797 * softirq as those do not count in task exec_runtime any more.
2799 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
2802 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
2803 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
2805 if (steal_account_process_tick())
2808 if (irqtime_account_hi_update()) {
2809 cpustat
[CPUTIME_IRQ
] += (__force u64
) cputime_one_jiffy
;
2810 } else if (irqtime_account_si_update()) {
2811 cpustat
[CPUTIME_SOFTIRQ
] += (__force u64
) cputime_one_jiffy
;
2812 } else if (this_cpu_ksoftirqd() == p
) {
2814 * ksoftirqd time do not get accounted in cpu_softirq_time.
2815 * So, we have to handle it separately here.
2816 * Also, p->stime needs to be updated for ksoftirqd.
2818 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
2820 } else if (user_tick
) {
2821 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
2822 } else if (p
== rq
->idle
) {
2823 account_idle_time(cputime_one_jiffy
);
2824 } else if (p
->flags
& PF_VCPU
) { /* System time or guest time */
2825 account_guest_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
2827 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
2832 static void irqtime_account_idle_ticks(int ticks
)
2835 struct rq
*rq
= this_rq();
2837 for (i
= 0; i
< ticks
; i
++)
2838 irqtime_account_process_tick(current
, 0, rq
);
2840 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
2841 static void irqtime_account_idle_ticks(int ticks
) {}
2842 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
2844 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
2847 * Account a single tick of cpu time.
2848 * @p: the process that the cpu time gets accounted to
2849 * @user_tick: indicates if the tick is a user or a system tick
2851 void account_process_tick(struct task_struct
*p
, int user_tick
)
2853 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
2854 struct rq
*rq
= this_rq();
2856 if (sched_clock_irqtime
) {
2857 irqtime_account_process_tick(p
, user_tick
, rq
);
2861 if (steal_account_process_tick())
2865 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
2866 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
2867 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
2870 account_idle_time(cputime_one_jiffy
);
2874 * Account multiple ticks of steal time.
2875 * @p: the process from which the cpu time has been stolen
2876 * @ticks: number of stolen ticks
2878 void account_steal_ticks(unsigned long ticks
)
2880 account_steal_time(jiffies_to_cputime(ticks
));
2884 * Account multiple ticks of idle time.
2885 * @ticks: number of stolen ticks
2887 void account_idle_ticks(unsigned long ticks
)
2890 if (sched_clock_irqtime
) {
2891 irqtime_account_idle_ticks(ticks
);
2895 account_idle_time(jiffies_to_cputime(ticks
));
2901 * Use precise platform statistics if available:
2903 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
2904 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
2910 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
2912 struct task_cputime cputime
;
2914 thread_group_cputime(p
, &cputime
);
2916 *ut
= cputime
.utime
;
2917 *st
= cputime
.stime
;
2921 #ifndef nsecs_to_cputime
2922 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
2925 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
2927 cputime_t rtime
, utime
= p
->utime
, total
= utime
+ p
->stime
;
2930 * Use CFS's precise accounting:
2932 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
2935 u64 temp
= (__force u64
) rtime
;
2937 temp
*= (__force u64
) utime
;
2938 do_div(temp
, (__force u32
) total
);
2939 utime
= (__force cputime_t
) temp
;
2944 * Compare with previous values, to keep monotonicity:
2946 p
->prev_utime
= max(p
->prev_utime
, utime
);
2947 p
->prev_stime
= max(p
->prev_stime
, rtime
- p
->prev_utime
);
2949 *ut
= p
->prev_utime
;
2950 *st
= p
->prev_stime
;
2954 * Must be called with siglock held.
2956 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
2958 struct signal_struct
*sig
= p
->signal
;
2959 struct task_cputime cputime
;
2960 cputime_t rtime
, utime
, total
;
2962 thread_group_cputime(p
, &cputime
);
2964 total
= cputime
.utime
+ cputime
.stime
;
2965 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
2968 u64 temp
= (__force u64
) rtime
;
2970 temp
*= (__force u64
) cputime
.utime
;
2971 do_div(temp
, (__force u32
) total
);
2972 utime
= (__force cputime_t
) temp
;
2976 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
2977 sig
->prev_stime
= max(sig
->prev_stime
, rtime
- sig
->prev_utime
);
2979 *ut
= sig
->prev_utime
;
2980 *st
= sig
->prev_stime
;
2985 * This function gets called by the timer code, with HZ frequency.
2986 * We call it with interrupts disabled.
2988 void scheduler_tick(void)
2990 int cpu
= smp_processor_id();
2991 struct rq
*rq
= cpu_rq(cpu
);
2992 struct task_struct
*curr
= rq
->curr
;
2996 raw_spin_lock(&rq
->lock
);
2997 update_rq_clock(rq
);
2998 update_cpu_load_active(rq
);
2999 curr
->sched_class
->task_tick(rq
, curr
, 0);
3000 raw_spin_unlock(&rq
->lock
);
3002 perf_event_task_tick();
3005 rq
->idle_balance
= idle_cpu(cpu
);
3006 trigger_load_balance(rq
, cpu
);
3010 notrace
unsigned long get_parent_ip(unsigned long addr
)
3012 if (in_lock_functions(addr
)) {
3013 addr
= CALLER_ADDR2
;
3014 if (in_lock_functions(addr
))
3015 addr
= CALLER_ADDR3
;
3020 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3021 defined(CONFIG_PREEMPT_TRACER))
3023 void __kprobes
add_preempt_count(int val
)
3025 #ifdef CONFIG_DEBUG_PREEMPT
3029 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3032 preempt_count() += val
;
3033 #ifdef CONFIG_DEBUG_PREEMPT
3035 * Spinlock count overflowing soon?
3037 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3040 if (preempt_count() == val
)
3041 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3043 EXPORT_SYMBOL(add_preempt_count
);
3045 void __kprobes
sub_preempt_count(int val
)
3047 #ifdef CONFIG_DEBUG_PREEMPT
3051 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3054 * Is the spinlock portion underflowing?
3056 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3057 !(preempt_count() & PREEMPT_MASK
)))
3061 if (preempt_count() == val
)
3062 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3063 preempt_count() -= val
;
3065 EXPORT_SYMBOL(sub_preempt_count
);
3070 * Print scheduling while atomic bug:
3072 static noinline
void __schedule_bug(struct task_struct
*prev
)
3074 struct pt_regs
*regs
= get_irq_regs();
3076 if (oops_in_progress
)
3079 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3080 prev
->comm
, prev
->pid
, preempt_count());
3082 debug_show_held_locks(prev
);
3084 if (irqs_disabled())
3085 print_irqtrace_events(prev
);
3094 * Various schedule()-time debugging checks and statistics:
3096 static inline void schedule_debug(struct task_struct
*prev
)
3099 * Test if we are atomic. Since do_exit() needs to call into
3100 * schedule() atomically, we ignore that path for now.
3101 * Otherwise, whine if we are scheduling when we should not be.
3103 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
3104 __schedule_bug(prev
);
3107 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
3109 schedstat_inc(this_rq(), sched_count
);
3112 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
3114 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
3115 update_rq_clock(rq
);
3116 prev
->sched_class
->put_prev_task(rq
, prev
);
3120 * Pick up the highest-prio task:
3122 static inline struct task_struct
*
3123 pick_next_task(struct rq
*rq
)
3125 const struct sched_class
*class;
3126 struct task_struct
*p
;
3129 * Optimization: we know that if all tasks are in
3130 * the fair class we can call that function directly:
3132 if (likely(rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
3133 p
= fair_sched_class
.pick_next_task(rq
);
3138 for_each_class(class) {
3139 p
= class->pick_next_task(rq
);
3144 BUG(); /* the idle class will always have a runnable task */
3148 * __schedule() is the main scheduler function.
3150 static void __sched
__schedule(void)
3152 struct task_struct
*prev
, *next
;
3153 unsigned long *switch_count
;
3159 cpu
= smp_processor_id();
3161 rcu_note_context_switch(cpu
);
3164 schedule_debug(prev
);
3166 if (sched_feat(HRTICK
))
3169 raw_spin_lock_irq(&rq
->lock
);
3171 switch_count
= &prev
->nivcsw
;
3172 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
3173 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
3174 prev
->state
= TASK_RUNNING
;
3176 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
3180 * If a worker went to sleep, notify and ask workqueue
3181 * whether it wants to wake up a task to maintain
3184 if (prev
->flags
& PF_WQ_WORKER
) {
3185 struct task_struct
*to_wakeup
;
3187 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
3189 try_to_wake_up_local(to_wakeup
);
3192 switch_count
= &prev
->nvcsw
;
3195 pre_schedule(rq
, prev
);
3197 if (unlikely(!rq
->nr_running
))
3198 idle_balance(cpu
, rq
);
3200 put_prev_task(rq
, prev
);
3201 next
= pick_next_task(rq
);
3202 clear_tsk_need_resched(prev
);
3203 rq
->skip_clock_update
= 0;
3205 if (likely(prev
!= next
)) {
3210 context_switch(rq
, prev
, next
); /* unlocks the rq */
3212 * The context switch have flipped the stack from under us
3213 * and restored the local variables which were saved when
3214 * this task called schedule() in the past. prev == current
3215 * is still correct, but it can be moved to another cpu/rq.
3217 cpu
= smp_processor_id();
3220 raw_spin_unlock_irq(&rq
->lock
);
3224 preempt_enable_no_resched();
3229 static inline void sched_submit_work(struct task_struct
*tsk
)
3234 * If we are going to sleep and we have plugged IO queued,
3235 * make sure to submit it to avoid deadlocks.
3237 if (blk_needs_flush_plug(tsk
))
3238 blk_schedule_flush_plug(tsk
);
3241 asmlinkage
void __sched
schedule(void)
3243 struct task_struct
*tsk
= current
;
3245 sched_submit_work(tsk
);
3248 EXPORT_SYMBOL(schedule
);
3250 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3252 static inline bool owner_running(struct mutex
*lock
, struct task_struct
*owner
)
3254 if (lock
->owner
!= owner
)
3258 * Ensure we emit the owner->on_cpu, dereference _after_ checking
3259 * lock->owner still matches owner, if that fails, owner might
3260 * point to free()d memory, if it still matches, the rcu_read_lock()
3261 * ensures the memory stays valid.
3265 return owner
->on_cpu
;
3269 * Look out! "owner" is an entirely speculative pointer
3270 * access and not reliable.
3272 int mutex_spin_on_owner(struct mutex
*lock
, struct task_struct
*owner
)
3274 if (!sched_feat(OWNER_SPIN
))
3278 while (owner_running(lock
, owner
)) {
3282 arch_mutex_cpu_relax();
3287 * We break out the loop above on need_resched() and when the
3288 * owner changed, which is a sign for heavy contention. Return
3289 * success only when lock->owner is NULL.
3291 return lock
->owner
== NULL
;
3295 #ifdef CONFIG_PREEMPT
3297 * this is the entry point to schedule() from in-kernel preemption
3298 * off of preempt_enable. Kernel preemptions off return from interrupt
3299 * occur there and call schedule directly.
3301 asmlinkage
void __sched notrace
preempt_schedule(void)
3303 struct thread_info
*ti
= current_thread_info();
3306 * If there is a non-zero preempt_count or interrupts are disabled,
3307 * we do not want to preempt the current task. Just return..
3309 if (likely(ti
->preempt_count
|| irqs_disabled()))
3313 add_preempt_count_notrace(PREEMPT_ACTIVE
);
3315 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
3318 * Check again in case we missed a preemption opportunity
3319 * between schedule and now.
3322 } while (need_resched());
3324 EXPORT_SYMBOL(preempt_schedule
);
3327 * this is the entry point to schedule() from kernel preemption
3328 * off of irq context.
3329 * Note, that this is called and return with irqs disabled. This will
3330 * protect us against recursive calling from irq.
3332 asmlinkage
void __sched
preempt_schedule_irq(void)
3334 struct thread_info
*ti
= current_thread_info();
3336 /* Catch callers which need to be fixed */
3337 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
3340 add_preempt_count(PREEMPT_ACTIVE
);
3343 local_irq_disable();
3344 sub_preempt_count(PREEMPT_ACTIVE
);
3347 * Check again in case we missed a preemption opportunity
3348 * between schedule and now.
3351 } while (need_resched());
3354 #endif /* CONFIG_PREEMPT */
3356 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
3359 return try_to_wake_up(curr
->private, mode
, wake_flags
);
3361 EXPORT_SYMBOL(default_wake_function
);
3364 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3365 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3366 * number) then we wake all the non-exclusive tasks and one exclusive task.
3368 * There are circumstances in which we can try to wake a task which has already
3369 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3370 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3372 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
3373 int nr_exclusive
, int wake_flags
, void *key
)
3375 wait_queue_t
*curr
, *next
;
3377 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
3378 unsigned flags
= curr
->flags
;
3380 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
3381 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
3387 * __wake_up - wake up threads blocked on a waitqueue.
3389 * @mode: which threads
3390 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3391 * @key: is directly passed to the wakeup function
3393 * It may be assumed that this function implies a write memory barrier before
3394 * changing the task state if and only if any tasks are woken up.
3396 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
3397 int nr_exclusive
, void *key
)
3399 unsigned long flags
;
3401 spin_lock_irqsave(&q
->lock
, flags
);
3402 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
3403 spin_unlock_irqrestore(&q
->lock
, flags
);
3405 EXPORT_SYMBOL(__wake_up
);
3408 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3410 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
3412 __wake_up_common(q
, mode
, 1, 0, NULL
);
3414 EXPORT_SYMBOL_GPL(__wake_up_locked
);
3416 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
3418 __wake_up_common(q
, mode
, 1, 0, key
);
3420 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
3423 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
3425 * @mode: which threads
3426 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3427 * @key: opaque value to be passed to wakeup targets
3429 * The sync wakeup differs that the waker knows that it will schedule
3430 * away soon, so while the target thread will be woken up, it will not
3431 * be migrated to another CPU - ie. the two threads are 'synchronized'
3432 * with each other. This can prevent needless bouncing between CPUs.
3434 * On UP it can prevent extra preemption.
3436 * It may be assumed that this function implies a write memory barrier before
3437 * changing the task state if and only if any tasks are woken up.
3439 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
3440 int nr_exclusive
, void *key
)
3442 unsigned long flags
;
3443 int wake_flags
= WF_SYNC
;
3448 if (unlikely(!nr_exclusive
))
3451 spin_lock_irqsave(&q
->lock
, flags
);
3452 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
3453 spin_unlock_irqrestore(&q
->lock
, flags
);
3455 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
3458 * __wake_up_sync - see __wake_up_sync_key()
3460 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
3462 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
3464 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
3467 * complete: - signals a single thread waiting on this completion
3468 * @x: holds the state of this particular completion
3470 * This will wake up a single thread waiting on this completion. Threads will be
3471 * awakened in the same order in which they were queued.
3473 * See also complete_all(), wait_for_completion() and related routines.
3475 * It may be assumed that this function implies a write memory barrier before
3476 * changing the task state if and only if any tasks are woken up.
3478 void complete(struct completion
*x
)
3480 unsigned long flags
;
3482 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3484 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
3485 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3487 EXPORT_SYMBOL(complete
);
3490 * complete_all: - signals all threads waiting on this completion
3491 * @x: holds the state of this particular completion
3493 * This will wake up all threads waiting on this particular completion event.
3495 * It may be assumed that this function implies a write memory barrier before
3496 * changing the task state if and only if any tasks are woken up.
3498 void complete_all(struct completion
*x
)
3500 unsigned long flags
;
3502 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3503 x
->done
+= UINT_MAX
/2;
3504 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
3505 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3507 EXPORT_SYMBOL(complete_all
);
3509 static inline long __sched
3510 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
3513 DECLARE_WAITQUEUE(wait
, current
);
3515 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
3517 if (signal_pending_state(state
, current
)) {
3518 timeout
= -ERESTARTSYS
;
3521 __set_current_state(state
);
3522 spin_unlock_irq(&x
->wait
.lock
);
3523 timeout
= schedule_timeout(timeout
);
3524 spin_lock_irq(&x
->wait
.lock
);
3525 } while (!x
->done
&& timeout
);
3526 __remove_wait_queue(&x
->wait
, &wait
);
3531 return timeout
?: 1;
3535 wait_for_common(struct completion
*x
, long timeout
, int state
)
3539 spin_lock_irq(&x
->wait
.lock
);
3540 timeout
= do_wait_for_common(x
, timeout
, state
);
3541 spin_unlock_irq(&x
->wait
.lock
);
3546 * wait_for_completion: - waits for completion of a task
3547 * @x: holds the state of this particular completion
3549 * This waits to be signaled for completion of a specific task. It is NOT
3550 * interruptible and there is no timeout.
3552 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
3553 * and interrupt capability. Also see complete().
3555 void __sched
wait_for_completion(struct completion
*x
)
3557 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
3559 EXPORT_SYMBOL(wait_for_completion
);
3562 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
3563 * @x: holds the state of this particular completion
3564 * @timeout: timeout value in jiffies
3566 * This waits for either a completion of a specific task to be signaled or for a
3567 * specified timeout to expire. The timeout is in jiffies. It is not
3570 * The return value is 0 if timed out, and positive (at least 1, or number of
3571 * jiffies left till timeout) if completed.
3573 unsigned long __sched
3574 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
3576 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
3578 EXPORT_SYMBOL(wait_for_completion_timeout
);
3581 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
3582 * @x: holds the state of this particular completion
3584 * This waits for completion of a specific task to be signaled. It is
3587 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3589 int __sched
wait_for_completion_interruptible(struct completion
*x
)
3591 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
3592 if (t
== -ERESTARTSYS
)
3596 EXPORT_SYMBOL(wait_for_completion_interruptible
);
3599 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
3600 * @x: holds the state of this particular completion
3601 * @timeout: timeout value in jiffies
3603 * This waits for either a completion of a specific task to be signaled or for a
3604 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
3606 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3607 * positive (at least 1, or number of jiffies left till timeout) if completed.
3610 wait_for_completion_interruptible_timeout(struct completion
*x
,
3611 unsigned long timeout
)
3613 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
3615 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
3618 * wait_for_completion_killable: - waits for completion of a task (killable)
3619 * @x: holds the state of this particular completion
3621 * This waits to be signaled for completion of a specific task. It can be
3622 * interrupted by a kill signal.
3624 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3626 int __sched
wait_for_completion_killable(struct completion
*x
)
3628 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
3629 if (t
== -ERESTARTSYS
)
3633 EXPORT_SYMBOL(wait_for_completion_killable
);
3636 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
3637 * @x: holds the state of this particular completion
3638 * @timeout: timeout value in jiffies
3640 * This waits for either a completion of a specific task to be
3641 * signaled or for a specified timeout to expire. It can be
3642 * interrupted by a kill signal. The timeout is in jiffies.
3644 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3645 * positive (at least 1, or number of jiffies left till timeout) if completed.
3648 wait_for_completion_killable_timeout(struct completion
*x
,
3649 unsigned long timeout
)
3651 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
3653 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
3656 * try_wait_for_completion - try to decrement a completion without blocking
3657 * @x: completion structure
3659 * Returns: 0 if a decrement cannot be done without blocking
3660 * 1 if a decrement succeeded.
3662 * If a completion is being used as a counting completion,
3663 * attempt to decrement the counter without blocking. This
3664 * enables us to avoid waiting if the resource the completion
3665 * is protecting is not available.
3667 bool try_wait_for_completion(struct completion
*x
)
3669 unsigned long flags
;
3672 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3677 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3680 EXPORT_SYMBOL(try_wait_for_completion
);
3683 * completion_done - Test to see if a completion has any waiters
3684 * @x: completion structure
3686 * Returns: 0 if there are waiters (wait_for_completion() in progress)
3687 * 1 if there are no waiters.
3690 bool completion_done(struct completion
*x
)
3692 unsigned long flags
;
3695 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3698 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3701 EXPORT_SYMBOL(completion_done
);
3704 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
3706 unsigned long flags
;
3709 init_waitqueue_entry(&wait
, current
);
3711 __set_current_state(state
);
3713 spin_lock_irqsave(&q
->lock
, flags
);
3714 __add_wait_queue(q
, &wait
);
3715 spin_unlock(&q
->lock
);
3716 timeout
= schedule_timeout(timeout
);
3717 spin_lock_irq(&q
->lock
);
3718 __remove_wait_queue(q
, &wait
);
3719 spin_unlock_irqrestore(&q
->lock
, flags
);
3724 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
3726 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3728 EXPORT_SYMBOL(interruptible_sleep_on
);
3731 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3733 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
3735 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
3737 void __sched
sleep_on(wait_queue_head_t
*q
)
3739 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3741 EXPORT_SYMBOL(sleep_on
);
3743 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3745 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
3747 EXPORT_SYMBOL(sleep_on_timeout
);
3749 #ifdef CONFIG_RT_MUTEXES
3752 * rt_mutex_setprio - set the current priority of a task
3754 * @prio: prio value (kernel-internal form)
3756 * This function changes the 'effective' priority of a task. It does
3757 * not touch ->normal_prio like __setscheduler().
3759 * Used by the rt_mutex code to implement priority inheritance logic.
3761 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
3763 int oldprio
, on_rq
, running
;
3765 const struct sched_class
*prev_class
;
3767 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
3769 rq
= __task_rq_lock(p
);
3771 trace_sched_pi_setprio(p
, prio
);
3773 prev_class
= p
->sched_class
;
3775 running
= task_current(rq
, p
);
3777 dequeue_task(rq
, p
, 0);
3779 p
->sched_class
->put_prev_task(rq
, p
);
3782 p
->sched_class
= &rt_sched_class
;
3784 p
->sched_class
= &fair_sched_class
;
3789 p
->sched_class
->set_curr_task(rq
);
3791 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
3793 check_class_changed(rq
, p
, prev_class
, oldprio
);
3794 __task_rq_unlock(rq
);
3799 void set_user_nice(struct task_struct
*p
, long nice
)
3801 int old_prio
, delta
, on_rq
;
3802 unsigned long flags
;
3805 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
3808 * We have to be careful, if called from sys_setpriority(),
3809 * the task might be in the middle of scheduling on another CPU.
3811 rq
= task_rq_lock(p
, &flags
);
3813 * The RT priorities are set via sched_setscheduler(), but we still
3814 * allow the 'normal' nice value to be set - but as expected
3815 * it wont have any effect on scheduling until the task is
3816 * SCHED_FIFO/SCHED_RR:
3818 if (task_has_rt_policy(p
)) {
3819 p
->static_prio
= NICE_TO_PRIO(nice
);
3824 dequeue_task(rq
, p
, 0);
3826 p
->static_prio
= NICE_TO_PRIO(nice
);
3829 p
->prio
= effective_prio(p
);
3830 delta
= p
->prio
- old_prio
;
3833 enqueue_task(rq
, p
, 0);
3835 * If the task increased its priority or is running and
3836 * lowered its priority, then reschedule its CPU:
3838 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3839 resched_task(rq
->curr
);
3842 task_rq_unlock(rq
, p
, &flags
);
3844 EXPORT_SYMBOL(set_user_nice
);
3847 * can_nice - check if a task can reduce its nice value
3851 int can_nice(const struct task_struct
*p
, const int nice
)
3853 /* convert nice value [19,-20] to rlimit style value [1,40] */
3854 int nice_rlim
= 20 - nice
;
3856 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3857 capable(CAP_SYS_NICE
));
3860 #ifdef __ARCH_WANT_SYS_NICE
3863 * sys_nice - change the priority of the current process.
3864 * @increment: priority increment
3866 * sys_setpriority is a more generic, but much slower function that
3867 * does similar things.
3869 SYSCALL_DEFINE1(nice
, int, increment
)
3874 * Setpriority might change our priority at the same moment.
3875 * We don't have to worry. Conceptually one call occurs first
3876 * and we have a single winner.
3878 if (increment
< -40)
3883 nice
= TASK_NICE(current
) + increment
;
3889 if (increment
< 0 && !can_nice(current
, nice
))
3892 retval
= security_task_setnice(current
, nice
);
3896 set_user_nice(current
, nice
);
3903 * task_prio - return the priority value of a given task.
3904 * @p: the task in question.
3906 * This is the priority value as seen by users in /proc.
3907 * RT tasks are offset by -200. Normal tasks are centered
3908 * around 0, value goes from -16 to +15.
3910 int task_prio(const struct task_struct
*p
)
3912 return p
->prio
- MAX_RT_PRIO
;
3916 * task_nice - return the nice value of a given task.
3917 * @p: the task in question.
3919 int task_nice(const struct task_struct
*p
)
3921 return TASK_NICE(p
);
3923 EXPORT_SYMBOL(task_nice
);
3926 * idle_cpu - is a given cpu idle currently?
3927 * @cpu: the processor in question.
3929 int idle_cpu(int cpu
)
3931 struct rq
*rq
= cpu_rq(cpu
);
3933 if (rq
->curr
!= rq
->idle
)
3940 if (!llist_empty(&rq
->wake_list
))
3948 * idle_task - return the idle task for a given cpu.
3949 * @cpu: the processor in question.
3951 struct task_struct
*idle_task(int cpu
)
3953 return cpu_rq(cpu
)->idle
;
3957 * find_process_by_pid - find a process with a matching PID value.
3958 * @pid: the pid in question.
3960 static struct task_struct
*find_process_by_pid(pid_t pid
)
3962 return pid
? find_task_by_vpid(pid
) : current
;
3965 /* Actually do priority change: must hold rq lock. */
3967 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
3970 p
->rt_priority
= prio
;
3971 p
->normal_prio
= normal_prio(p
);
3972 /* we are holding p->pi_lock already */
3973 p
->prio
= rt_mutex_getprio(p
);
3974 if (rt_prio(p
->prio
))
3975 p
->sched_class
= &rt_sched_class
;
3977 p
->sched_class
= &fair_sched_class
;
3982 * check the target process has a UID that matches the current process's
3984 static bool check_same_owner(struct task_struct
*p
)
3986 const struct cred
*cred
= current_cred(), *pcred
;
3990 pcred
= __task_cred(p
);
3991 if (cred
->user
->user_ns
== pcred
->user
->user_ns
)
3992 match
= (cred
->euid
== pcred
->euid
||
3993 cred
->euid
== pcred
->uid
);
4000 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
4001 const struct sched_param
*param
, bool user
)
4003 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4004 unsigned long flags
;
4005 const struct sched_class
*prev_class
;
4009 /* may grab non-irq protected spin_locks */
4010 BUG_ON(in_interrupt());
4012 /* double check policy once rq lock held */
4014 reset_on_fork
= p
->sched_reset_on_fork
;
4015 policy
= oldpolicy
= p
->policy
;
4017 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
4018 policy
&= ~SCHED_RESET_ON_FORK
;
4020 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4021 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4022 policy
!= SCHED_IDLE
)
4027 * Valid priorities for SCHED_FIFO and SCHED_RR are
4028 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4029 * SCHED_BATCH and SCHED_IDLE is 0.
4031 if (param
->sched_priority
< 0 ||
4032 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4033 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4035 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4039 * Allow unprivileged RT tasks to decrease priority:
4041 if (user
&& !capable(CAP_SYS_NICE
)) {
4042 if (rt_policy(policy
)) {
4043 unsigned long rlim_rtprio
=
4044 task_rlimit(p
, RLIMIT_RTPRIO
);
4046 /* can't set/change the rt policy */
4047 if (policy
!= p
->policy
&& !rlim_rtprio
)
4050 /* can't increase priority */
4051 if (param
->sched_priority
> p
->rt_priority
&&
4052 param
->sched_priority
> rlim_rtprio
)
4057 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4058 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4060 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
4061 if (!can_nice(p
, TASK_NICE(p
)))
4065 /* can't change other user's priorities */
4066 if (!check_same_owner(p
))
4069 /* Normal users shall not reset the sched_reset_on_fork flag */
4070 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
4075 retval
= security_task_setscheduler(p
);
4081 * make sure no PI-waiters arrive (or leave) while we are
4082 * changing the priority of the task:
4084 * To be able to change p->policy safely, the appropriate
4085 * runqueue lock must be held.
4087 rq
= task_rq_lock(p
, &flags
);
4090 * Changing the policy of the stop threads its a very bad idea
4092 if (p
== rq
->stop
) {
4093 task_rq_unlock(rq
, p
, &flags
);
4098 * If not changing anything there's no need to proceed further:
4100 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
4101 param
->sched_priority
== p
->rt_priority
))) {
4103 __task_rq_unlock(rq
);
4104 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4108 #ifdef CONFIG_RT_GROUP_SCHED
4111 * Do not allow realtime tasks into groups that have no runtime
4114 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
4115 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
4116 !task_group_is_autogroup(task_group(p
))) {
4117 task_rq_unlock(rq
, p
, &flags
);
4123 /* recheck policy now with rq lock held */
4124 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4125 policy
= oldpolicy
= -1;
4126 task_rq_unlock(rq
, p
, &flags
);
4130 running
= task_current(rq
, p
);
4132 dequeue_task(rq
, p
, 0);
4134 p
->sched_class
->put_prev_task(rq
, p
);
4136 p
->sched_reset_on_fork
= reset_on_fork
;
4139 prev_class
= p
->sched_class
;
4140 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4143 p
->sched_class
->set_curr_task(rq
);
4145 enqueue_task(rq
, p
, 0);
4147 check_class_changed(rq
, p
, prev_class
, oldprio
);
4148 task_rq_unlock(rq
, p
, &flags
);
4150 rt_mutex_adjust_pi(p
);
4156 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4157 * @p: the task in question.
4158 * @policy: new policy.
4159 * @param: structure containing the new RT priority.
4161 * NOTE that the task may be already dead.
4163 int sched_setscheduler(struct task_struct
*p
, int policy
,
4164 const struct sched_param
*param
)
4166 return __sched_setscheduler(p
, policy
, param
, true);
4168 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4171 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4172 * @p: the task in question.
4173 * @policy: new policy.
4174 * @param: structure containing the new RT priority.
4176 * Just like sched_setscheduler, only don't bother checking if the
4177 * current context has permission. For example, this is needed in
4178 * stop_machine(): we create temporary high priority worker threads,
4179 * but our caller might not have that capability.
4181 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
4182 const struct sched_param
*param
)
4184 return __sched_setscheduler(p
, policy
, param
, false);
4188 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4190 struct sched_param lparam
;
4191 struct task_struct
*p
;
4194 if (!param
|| pid
< 0)
4196 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4201 p
= find_process_by_pid(pid
);
4203 retval
= sched_setscheduler(p
, policy
, &lparam
);
4210 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4211 * @pid: the pid in question.
4212 * @policy: new policy.
4213 * @param: structure containing the new RT priority.
4215 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
4216 struct sched_param __user
*, param
)
4218 /* negative values for policy are not valid */
4222 return do_sched_setscheduler(pid
, policy
, param
);
4226 * sys_sched_setparam - set/change the RT priority of a thread
4227 * @pid: the pid in question.
4228 * @param: structure containing the new RT priority.
4230 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4232 return do_sched_setscheduler(pid
, -1, param
);
4236 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4237 * @pid: the pid in question.
4239 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
4241 struct task_struct
*p
;
4249 p
= find_process_by_pid(pid
);
4251 retval
= security_task_getscheduler(p
);
4254 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
4261 * sys_sched_getparam - get the RT priority of a thread
4262 * @pid: the pid in question.
4263 * @param: structure containing the RT priority.
4265 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4267 struct sched_param lp
;
4268 struct task_struct
*p
;
4271 if (!param
|| pid
< 0)
4275 p
= find_process_by_pid(pid
);
4280 retval
= security_task_getscheduler(p
);
4284 lp
.sched_priority
= p
->rt_priority
;
4288 * This one might sleep, we cannot do it with a spinlock held ...
4290 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4299 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4301 cpumask_var_t cpus_allowed
, new_mask
;
4302 struct task_struct
*p
;
4308 p
= find_process_by_pid(pid
);
4315 /* Prevent p going away */
4319 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4323 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4325 goto out_free_cpus_allowed
;
4328 if (!check_same_owner(p
) && !ns_capable(task_user_ns(p
), CAP_SYS_NICE
))
4331 retval
= security_task_setscheduler(p
);
4335 cpuset_cpus_allowed(p
, cpus_allowed
);
4336 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4338 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4341 cpuset_cpus_allowed(p
, cpus_allowed
);
4342 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4344 * We must have raced with a concurrent cpuset
4345 * update. Just reset the cpus_allowed to the
4346 * cpuset's cpus_allowed
4348 cpumask_copy(new_mask
, cpus_allowed
);
4353 free_cpumask_var(new_mask
);
4354 out_free_cpus_allowed
:
4355 free_cpumask_var(cpus_allowed
);
4362 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4363 struct cpumask
*new_mask
)
4365 if (len
< cpumask_size())
4366 cpumask_clear(new_mask
);
4367 else if (len
> cpumask_size())
4368 len
= cpumask_size();
4370 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4374 * sys_sched_setaffinity - set the cpu affinity of a process
4375 * @pid: pid of the process
4376 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4377 * @user_mask_ptr: user-space pointer to the new cpu mask
4379 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4380 unsigned long __user
*, user_mask_ptr
)
4382 cpumask_var_t new_mask
;
4385 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4388 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4390 retval
= sched_setaffinity(pid
, new_mask
);
4391 free_cpumask_var(new_mask
);
4395 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4397 struct task_struct
*p
;
4398 unsigned long flags
;
4405 p
= find_process_by_pid(pid
);
4409 retval
= security_task_getscheduler(p
);
4413 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4414 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
4415 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4425 * sys_sched_getaffinity - get the cpu affinity of a process
4426 * @pid: pid of the process
4427 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4428 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4430 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4431 unsigned long __user
*, user_mask_ptr
)
4436 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4438 if (len
& (sizeof(unsigned long)-1))
4441 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4444 ret
= sched_getaffinity(pid
, mask
);
4446 size_t retlen
= min_t(size_t, len
, cpumask_size());
4448 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4453 free_cpumask_var(mask
);
4459 * sys_sched_yield - yield the current processor to other threads.
4461 * This function yields the current CPU to other tasks. If there are no
4462 * other threads running on this CPU then this function will return.
4464 SYSCALL_DEFINE0(sched_yield
)
4466 struct rq
*rq
= this_rq_lock();
4468 schedstat_inc(rq
, yld_count
);
4469 current
->sched_class
->yield_task(rq
);
4472 * Since we are going to call schedule() anyway, there's
4473 * no need to preempt or enable interrupts:
4475 __release(rq
->lock
);
4476 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4477 do_raw_spin_unlock(&rq
->lock
);
4478 preempt_enable_no_resched();
4485 static inline int should_resched(void)
4487 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
4490 static void __cond_resched(void)
4492 add_preempt_count(PREEMPT_ACTIVE
);
4494 sub_preempt_count(PREEMPT_ACTIVE
);
4497 int __sched
_cond_resched(void)
4499 if (should_resched()) {
4505 EXPORT_SYMBOL(_cond_resched
);
4508 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4509 * call schedule, and on return reacquire the lock.
4511 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4512 * operations here to prevent schedule() from being called twice (once via
4513 * spin_unlock(), once by hand).
4515 int __cond_resched_lock(spinlock_t
*lock
)
4517 int resched
= should_resched();
4520 lockdep_assert_held(lock
);
4522 if (spin_needbreak(lock
) || resched
) {
4533 EXPORT_SYMBOL(__cond_resched_lock
);
4535 int __sched
__cond_resched_softirq(void)
4537 BUG_ON(!in_softirq());
4539 if (should_resched()) {
4547 EXPORT_SYMBOL(__cond_resched_softirq
);
4550 * yield - yield the current processor to other threads.
4552 * This is a shortcut for kernel-space yielding - it marks the
4553 * thread runnable and calls sys_sched_yield().
4555 void __sched
yield(void)
4557 set_current_state(TASK_RUNNING
);
4560 EXPORT_SYMBOL(yield
);
4563 * yield_to - yield the current processor to another thread in
4564 * your thread group, or accelerate that thread toward the
4565 * processor it's on.
4567 * @preempt: whether task preemption is allowed or not
4569 * It's the caller's job to ensure that the target task struct
4570 * can't go away on us before we can do any checks.
4572 * Returns true if we indeed boosted the target task.
4574 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
4576 struct task_struct
*curr
= current
;
4577 struct rq
*rq
, *p_rq
;
4578 unsigned long flags
;
4581 local_irq_save(flags
);
4586 double_rq_lock(rq
, p_rq
);
4587 while (task_rq(p
) != p_rq
) {
4588 double_rq_unlock(rq
, p_rq
);
4592 if (!curr
->sched_class
->yield_to_task
)
4595 if (curr
->sched_class
!= p
->sched_class
)
4598 if (task_running(p_rq
, p
) || p
->state
)
4601 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4603 schedstat_inc(rq
, yld_count
);
4605 * Make p's CPU reschedule; pick_next_entity takes care of
4608 if (preempt
&& rq
!= p_rq
)
4609 resched_task(p_rq
->curr
);
4612 * We might have set it in task_yield_fair(), but are
4613 * not going to schedule(), so don't want to skip
4616 rq
->skip_clock_update
= 0;
4620 double_rq_unlock(rq
, p_rq
);
4621 local_irq_restore(flags
);
4628 EXPORT_SYMBOL_GPL(yield_to
);
4631 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4632 * that process accounting knows that this is a task in IO wait state.
4634 void __sched
io_schedule(void)
4636 struct rq
*rq
= raw_rq();
4638 delayacct_blkio_start();
4639 atomic_inc(&rq
->nr_iowait
);
4640 blk_flush_plug(current
);
4641 current
->in_iowait
= 1;
4643 current
->in_iowait
= 0;
4644 atomic_dec(&rq
->nr_iowait
);
4645 delayacct_blkio_end();
4647 EXPORT_SYMBOL(io_schedule
);
4649 long __sched
io_schedule_timeout(long timeout
)
4651 struct rq
*rq
= raw_rq();
4654 delayacct_blkio_start();
4655 atomic_inc(&rq
->nr_iowait
);
4656 blk_flush_plug(current
);
4657 current
->in_iowait
= 1;
4658 ret
= schedule_timeout(timeout
);
4659 current
->in_iowait
= 0;
4660 atomic_dec(&rq
->nr_iowait
);
4661 delayacct_blkio_end();
4666 * sys_sched_get_priority_max - return maximum RT priority.
4667 * @policy: scheduling class.
4669 * this syscall returns the maximum rt_priority that can be used
4670 * by a given scheduling class.
4672 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4679 ret
= MAX_USER_RT_PRIO
-1;
4691 * sys_sched_get_priority_min - return minimum RT priority.
4692 * @policy: scheduling class.
4694 * this syscall returns the minimum rt_priority that can be used
4695 * by a given scheduling class.
4697 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4715 * sys_sched_rr_get_interval - return the default timeslice of a process.
4716 * @pid: pid of the process.
4717 * @interval: userspace pointer to the timeslice value.
4719 * this syscall writes the default timeslice value of a given process
4720 * into the user-space timespec buffer. A value of '0' means infinity.
4722 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4723 struct timespec __user
*, interval
)
4725 struct task_struct
*p
;
4726 unsigned int time_slice
;
4727 unsigned long flags
;
4737 p
= find_process_by_pid(pid
);
4741 retval
= security_task_getscheduler(p
);
4745 rq
= task_rq_lock(p
, &flags
);
4746 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4747 task_rq_unlock(rq
, p
, &flags
);
4750 jiffies_to_timespec(time_slice
, &t
);
4751 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4759 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4761 void sched_show_task(struct task_struct
*p
)
4763 unsigned long free
= 0;
4766 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4767 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4768 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4769 #if BITS_PER_LONG == 32
4770 if (state
== TASK_RUNNING
)
4771 printk(KERN_CONT
" running ");
4773 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4775 if (state
== TASK_RUNNING
)
4776 printk(KERN_CONT
" running task ");
4778 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4780 #ifdef CONFIG_DEBUG_STACK_USAGE
4781 free
= stack_not_used(p
);
4783 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4784 task_pid_nr(p
), task_pid_nr(rcu_dereference(p
->real_parent
)),
4785 (unsigned long)task_thread_info(p
)->flags
);
4787 show_stack(p
, NULL
);
4790 void show_state_filter(unsigned long state_filter
)
4792 struct task_struct
*g
, *p
;
4794 #if BITS_PER_LONG == 32
4796 " task PC stack pid father\n");
4799 " task PC stack pid father\n");
4802 do_each_thread(g
, p
) {
4804 * reset the NMI-timeout, listing all files on a slow
4805 * console might take a lot of time:
4807 touch_nmi_watchdog();
4808 if (!state_filter
|| (p
->state
& state_filter
))
4810 } while_each_thread(g
, p
);
4812 touch_all_softlockup_watchdogs();
4814 #ifdef CONFIG_SCHED_DEBUG
4815 sysrq_sched_debug_show();
4819 * Only show locks if all tasks are dumped:
4822 debug_show_all_locks();
4825 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
4827 idle
->sched_class
= &idle_sched_class
;
4831 * init_idle - set up an idle thread for a given CPU
4832 * @idle: task in question
4833 * @cpu: cpu the idle task belongs to
4835 * NOTE: this function does not set the idle thread's NEED_RESCHED
4836 * flag, to make booting more robust.
4838 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
4840 struct rq
*rq
= cpu_rq(cpu
);
4841 unsigned long flags
;
4843 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4846 idle
->state
= TASK_RUNNING
;
4847 idle
->se
.exec_start
= sched_clock();
4849 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4851 * We're having a chicken and egg problem, even though we are
4852 * holding rq->lock, the cpu isn't yet set to this cpu so the
4853 * lockdep check in task_group() will fail.
4855 * Similar case to sched_fork(). / Alternatively we could
4856 * use task_rq_lock() here and obtain the other rq->lock.
4861 __set_task_cpu(idle
, cpu
);
4864 rq
->curr
= rq
->idle
= idle
;
4865 #if defined(CONFIG_SMP)
4868 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4870 /* Set the preempt count _outside_ the spinlocks! */
4871 task_thread_info(idle
)->preempt_count
= 0;
4874 * The idle tasks have their own, simple scheduling class:
4876 idle
->sched_class
= &idle_sched_class
;
4877 ftrace_graph_init_idle_task(idle
, cpu
);
4878 #if defined(CONFIG_SMP)
4879 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4884 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4886 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4887 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4889 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4890 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
4894 * This is how migration works:
4896 * 1) we invoke migration_cpu_stop() on the target CPU using
4898 * 2) stopper starts to run (implicitly forcing the migrated thread
4900 * 3) it checks whether the migrated task is still in the wrong runqueue.
4901 * 4) if it's in the wrong runqueue then the migration thread removes
4902 * it and puts it into the right queue.
4903 * 5) stopper completes and stop_one_cpu() returns and the migration
4908 * Change a given task's CPU affinity. Migrate the thread to a
4909 * proper CPU and schedule it away if the CPU it's executing on
4910 * is removed from the allowed bitmask.
4912 * NOTE: the caller must have a valid reference to the task, the
4913 * task must not exit() & deallocate itself prematurely. The
4914 * call is not atomic; no spinlocks may be held.
4916 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4918 unsigned long flags
;
4920 unsigned int dest_cpu
;
4923 rq
= task_rq_lock(p
, &flags
);
4925 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4928 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4933 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
)) {
4938 do_set_cpus_allowed(p
, new_mask
);
4940 /* Can the task run on the task's current CPU? If so, we're done */
4941 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4944 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4946 struct migration_arg arg
= { p
, dest_cpu
};
4947 /* Need help from migration thread: drop lock and wait. */
4948 task_rq_unlock(rq
, p
, &flags
);
4949 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4950 tlb_migrate_finish(p
->mm
);
4954 task_rq_unlock(rq
, p
, &flags
);
4958 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4961 * Move (not current) task off this cpu, onto dest cpu. We're doing
4962 * this because either it can't run here any more (set_cpus_allowed()
4963 * away from this CPU, or CPU going down), or because we're
4964 * attempting to rebalance this task on exec (sched_exec).
4966 * So we race with normal scheduler movements, but that's OK, as long
4967 * as the task is no longer on this CPU.
4969 * Returns non-zero if task was successfully migrated.
4971 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4973 struct rq
*rq_dest
, *rq_src
;
4976 if (unlikely(!cpu_active(dest_cpu
)))
4979 rq_src
= cpu_rq(src_cpu
);
4980 rq_dest
= cpu_rq(dest_cpu
);
4982 raw_spin_lock(&p
->pi_lock
);
4983 double_rq_lock(rq_src
, rq_dest
);
4984 /* Already moved. */
4985 if (task_cpu(p
) != src_cpu
)
4987 /* Affinity changed (again). */
4988 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4992 * If we're not on a rq, the next wake-up will ensure we're
4996 dequeue_task(rq_src
, p
, 0);
4997 set_task_cpu(p
, dest_cpu
);
4998 enqueue_task(rq_dest
, p
, 0);
4999 check_preempt_curr(rq_dest
, p
, 0);
5004 double_rq_unlock(rq_src
, rq_dest
);
5005 raw_spin_unlock(&p
->pi_lock
);
5010 * migration_cpu_stop - this will be executed by a highprio stopper thread
5011 * and performs thread migration by bumping thread off CPU then
5012 * 'pushing' onto another runqueue.
5014 static int migration_cpu_stop(void *data
)
5016 struct migration_arg
*arg
= data
;
5019 * The original target cpu might have gone down and we might
5020 * be on another cpu but it doesn't matter.
5022 local_irq_disable();
5023 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
5028 #ifdef CONFIG_HOTPLUG_CPU
5031 * Ensures that the idle task is using init_mm right before its cpu goes
5034 void idle_task_exit(void)
5036 struct mm_struct
*mm
= current
->active_mm
;
5038 BUG_ON(cpu_online(smp_processor_id()));
5041 switch_mm(mm
, &init_mm
, current
);
5046 * While a dead CPU has no uninterruptible tasks queued at this point,
5047 * it might still have a nonzero ->nr_uninterruptible counter, because
5048 * for performance reasons the counter is not stricly tracking tasks to
5049 * their home CPUs. So we just add the counter to another CPU's counter,
5050 * to keep the global sum constant after CPU-down:
5052 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5054 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
5056 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5057 rq_src
->nr_uninterruptible
= 0;
5061 * remove the tasks which were accounted by rq from calc_load_tasks.
5063 static void calc_global_load_remove(struct rq
*rq
)
5065 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
5066 rq
->calc_load_active
= 0;
5070 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5071 * try_to_wake_up()->select_task_rq().
5073 * Called with rq->lock held even though we'er in stop_machine() and
5074 * there's no concurrency possible, we hold the required locks anyway
5075 * because of lock validation efforts.
5077 static void migrate_tasks(unsigned int dead_cpu
)
5079 struct rq
*rq
= cpu_rq(dead_cpu
);
5080 struct task_struct
*next
, *stop
= rq
->stop
;
5084 * Fudge the rq selection such that the below task selection loop
5085 * doesn't get stuck on the currently eligible stop task.
5087 * We're currently inside stop_machine() and the rq is either stuck
5088 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5089 * either way we should never end up calling schedule() until we're
5094 /* Ensure any throttled groups are reachable by pick_next_task */
5095 unthrottle_offline_cfs_rqs(rq
);
5099 * There's this thread running, bail when that's the only
5102 if (rq
->nr_running
== 1)
5105 next
= pick_next_task(rq
);
5107 next
->sched_class
->put_prev_task(rq
, next
);
5109 /* Find suitable destination for @next, with force if needed. */
5110 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
5111 raw_spin_unlock(&rq
->lock
);
5113 __migrate_task(next
, dead_cpu
, dest_cpu
);
5115 raw_spin_lock(&rq
->lock
);
5121 #endif /* CONFIG_HOTPLUG_CPU */
5123 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5125 static struct ctl_table sd_ctl_dir
[] = {
5127 .procname
= "sched_domain",
5133 static struct ctl_table sd_ctl_root
[] = {
5135 .procname
= "kernel",
5137 .child
= sd_ctl_dir
,
5142 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5144 struct ctl_table
*entry
=
5145 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5150 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5152 struct ctl_table
*entry
;
5155 * In the intermediate directories, both the child directory and
5156 * procname are dynamically allocated and could fail but the mode
5157 * will always be set. In the lowest directory the names are
5158 * static strings and all have proc handlers.
5160 for (entry
= *tablep
; entry
->mode
; entry
++) {
5162 sd_free_ctl_entry(&entry
->child
);
5163 if (entry
->proc_handler
== NULL
)
5164 kfree(entry
->procname
);
5172 set_table_entry(struct ctl_table
*entry
,
5173 const char *procname
, void *data
, int maxlen
,
5174 umode_t mode
, proc_handler
*proc_handler
)
5176 entry
->procname
= procname
;
5178 entry
->maxlen
= maxlen
;
5180 entry
->proc_handler
= proc_handler
;
5183 static struct ctl_table
*
5184 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5186 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
5191 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5192 sizeof(long), 0644, proc_doulongvec_minmax
);
5193 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5194 sizeof(long), 0644, proc_doulongvec_minmax
);
5195 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5196 sizeof(int), 0644, proc_dointvec_minmax
);
5197 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5198 sizeof(int), 0644, proc_dointvec_minmax
);
5199 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5200 sizeof(int), 0644, proc_dointvec_minmax
);
5201 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5202 sizeof(int), 0644, proc_dointvec_minmax
);
5203 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5204 sizeof(int), 0644, proc_dointvec_minmax
);
5205 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5206 sizeof(int), 0644, proc_dointvec_minmax
);
5207 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5208 sizeof(int), 0644, proc_dointvec_minmax
);
5209 set_table_entry(&table
[9], "cache_nice_tries",
5210 &sd
->cache_nice_tries
,
5211 sizeof(int), 0644, proc_dointvec_minmax
);
5212 set_table_entry(&table
[10], "flags", &sd
->flags
,
5213 sizeof(int), 0644, proc_dointvec_minmax
);
5214 set_table_entry(&table
[11], "name", sd
->name
,
5215 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
5216 /* &table[12] is terminator */
5221 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5223 struct ctl_table
*entry
, *table
;
5224 struct sched_domain
*sd
;
5225 int domain_num
= 0, i
;
5228 for_each_domain(cpu
, sd
)
5230 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5235 for_each_domain(cpu
, sd
) {
5236 snprintf(buf
, 32, "domain%d", i
);
5237 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5239 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5246 static struct ctl_table_header
*sd_sysctl_header
;
5247 static void register_sched_domain_sysctl(void)
5249 int i
, cpu_num
= num_possible_cpus();
5250 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5253 WARN_ON(sd_ctl_dir
[0].child
);
5254 sd_ctl_dir
[0].child
= entry
;
5259 for_each_possible_cpu(i
) {
5260 snprintf(buf
, 32, "cpu%d", i
);
5261 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5263 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5267 WARN_ON(sd_sysctl_header
);
5268 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5271 /* may be called multiple times per register */
5272 static void unregister_sched_domain_sysctl(void)
5274 if (sd_sysctl_header
)
5275 unregister_sysctl_table(sd_sysctl_header
);
5276 sd_sysctl_header
= NULL
;
5277 if (sd_ctl_dir
[0].child
)
5278 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5281 static void register_sched_domain_sysctl(void)
5284 static void unregister_sched_domain_sysctl(void)
5289 static void set_rq_online(struct rq
*rq
)
5292 const struct sched_class
*class;
5294 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5297 for_each_class(class) {
5298 if (class->rq_online
)
5299 class->rq_online(rq
);
5304 static void set_rq_offline(struct rq
*rq
)
5307 const struct sched_class
*class;
5309 for_each_class(class) {
5310 if (class->rq_offline
)
5311 class->rq_offline(rq
);
5314 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5320 * migration_call - callback that gets triggered when a CPU is added.
5321 * Here we can start up the necessary migration thread for the new CPU.
5323 static int __cpuinit
5324 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5326 int cpu
= (long)hcpu
;
5327 unsigned long flags
;
5328 struct rq
*rq
= cpu_rq(cpu
);
5330 switch (action
& ~CPU_TASKS_FROZEN
) {
5332 case CPU_UP_PREPARE
:
5333 rq
->calc_load_update
= calc_load_update
;
5337 /* Update our root-domain */
5338 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5340 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5344 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5347 #ifdef CONFIG_HOTPLUG_CPU
5349 sched_ttwu_pending();
5350 /* Update our root-domain */
5351 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5353 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5357 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5358 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5360 migrate_nr_uninterruptible(rq
);
5361 calc_global_load_remove(rq
);
5366 update_max_interval();
5372 * Register at high priority so that task migration (migrate_all_tasks)
5373 * happens before everything else. This has to be lower priority than
5374 * the notifier in the perf_event subsystem, though.
5376 static struct notifier_block __cpuinitdata migration_notifier
= {
5377 .notifier_call
= migration_call
,
5378 .priority
= CPU_PRI_MIGRATION
,
5381 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
5382 unsigned long action
, void *hcpu
)
5384 switch (action
& ~CPU_TASKS_FROZEN
) {
5386 case CPU_DOWN_FAILED
:
5387 set_cpu_active((long)hcpu
, true);
5394 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
5395 unsigned long action
, void *hcpu
)
5397 switch (action
& ~CPU_TASKS_FROZEN
) {
5398 case CPU_DOWN_PREPARE
:
5399 set_cpu_active((long)hcpu
, false);
5406 static int __init
migration_init(void)
5408 void *cpu
= (void *)(long)smp_processor_id();
5411 /* Initialize migration for the boot CPU */
5412 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5413 BUG_ON(err
== NOTIFY_BAD
);
5414 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5415 register_cpu_notifier(&migration_notifier
);
5417 /* Register cpu active notifiers */
5418 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5419 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5423 early_initcall(migration_init
);
5428 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5430 #ifdef CONFIG_SCHED_DEBUG
5432 static __read_mostly
int sched_domain_debug_enabled
;
5434 static int __init
sched_domain_debug_setup(char *str
)
5436 sched_domain_debug_enabled
= 1;
5440 early_param("sched_debug", sched_domain_debug_setup
);
5442 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5443 struct cpumask
*groupmask
)
5445 struct sched_group
*group
= sd
->groups
;
5448 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5449 cpumask_clear(groupmask
);
5451 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5453 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5454 printk("does not load-balance\n");
5456 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5461 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5463 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5464 printk(KERN_ERR
"ERROR: domain->span does not contain "
5467 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5468 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5472 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5476 printk(KERN_ERR
"ERROR: group is NULL\n");
5480 if (!group
->sgp
->power
) {
5481 printk(KERN_CONT
"\n");
5482 printk(KERN_ERR
"ERROR: domain->cpu_power not "
5487 if (!cpumask_weight(sched_group_cpus(group
))) {
5488 printk(KERN_CONT
"\n");
5489 printk(KERN_ERR
"ERROR: empty group\n");
5493 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5494 printk(KERN_CONT
"\n");
5495 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5499 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5501 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
5503 printk(KERN_CONT
" %s", str
);
5504 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
5505 printk(KERN_CONT
" (cpu_power = %d)",
5509 group
= group
->next
;
5510 } while (group
!= sd
->groups
);
5511 printk(KERN_CONT
"\n");
5513 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5514 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5517 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5518 printk(KERN_ERR
"ERROR: parent span is not a superset "
5519 "of domain->span\n");
5523 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5527 if (!sched_domain_debug_enabled
)
5531 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5535 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5538 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5546 #else /* !CONFIG_SCHED_DEBUG */
5547 # define sched_domain_debug(sd, cpu) do { } while (0)
5548 #endif /* CONFIG_SCHED_DEBUG */
5550 static int sd_degenerate(struct sched_domain
*sd
)
5552 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5555 /* Following flags need at least 2 groups */
5556 if (sd
->flags
& (SD_LOAD_BALANCE
|
5557 SD_BALANCE_NEWIDLE
|
5561 SD_SHARE_PKG_RESOURCES
)) {
5562 if (sd
->groups
!= sd
->groups
->next
)
5566 /* Following flags don't use groups */
5567 if (sd
->flags
& (SD_WAKE_AFFINE
))
5574 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5576 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5578 if (sd_degenerate(parent
))
5581 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5584 /* Flags needing groups don't count if only 1 group in parent */
5585 if (parent
->groups
== parent
->groups
->next
) {
5586 pflags
&= ~(SD_LOAD_BALANCE
|
5587 SD_BALANCE_NEWIDLE
|
5591 SD_SHARE_PKG_RESOURCES
);
5592 if (nr_node_ids
== 1)
5593 pflags
&= ~SD_SERIALIZE
;
5595 if (~cflags
& pflags
)
5601 static void free_rootdomain(struct rcu_head
*rcu
)
5603 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5605 cpupri_cleanup(&rd
->cpupri
);
5606 free_cpumask_var(rd
->rto_mask
);
5607 free_cpumask_var(rd
->online
);
5608 free_cpumask_var(rd
->span
);
5612 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5614 struct root_domain
*old_rd
= NULL
;
5615 unsigned long flags
;
5617 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5622 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5625 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5628 * If we dont want to free the old_rt yet then
5629 * set old_rd to NULL to skip the freeing later
5632 if (!atomic_dec_and_test(&old_rd
->refcount
))
5636 atomic_inc(&rd
->refcount
);
5639 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5640 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5643 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5646 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5649 static int init_rootdomain(struct root_domain
*rd
)
5651 memset(rd
, 0, sizeof(*rd
));
5653 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5655 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5657 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5660 if (cpupri_init(&rd
->cpupri
) != 0)
5665 free_cpumask_var(rd
->rto_mask
);
5667 free_cpumask_var(rd
->online
);
5669 free_cpumask_var(rd
->span
);
5675 * By default the system creates a single root-domain with all cpus as
5676 * members (mimicking the global state we have today).
5678 struct root_domain def_root_domain
;
5680 static void init_defrootdomain(void)
5682 init_rootdomain(&def_root_domain
);
5684 atomic_set(&def_root_domain
.refcount
, 1);
5687 static struct root_domain
*alloc_rootdomain(void)
5689 struct root_domain
*rd
;
5691 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5695 if (init_rootdomain(rd
) != 0) {
5703 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
5705 struct sched_group
*tmp
, *first
;
5714 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
5719 } while (sg
!= first
);
5722 static void free_sched_domain(struct rcu_head
*rcu
)
5724 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5727 * If its an overlapping domain it has private groups, iterate and
5730 if (sd
->flags
& SD_OVERLAP
) {
5731 free_sched_groups(sd
->groups
, 1);
5732 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5733 kfree(sd
->groups
->sgp
);
5739 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5741 call_rcu(&sd
->rcu
, free_sched_domain
);
5744 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5746 for (; sd
; sd
= sd
->parent
)
5747 destroy_sched_domain(sd
, cpu
);
5751 * Keep a special pointer to the highest sched_domain that has
5752 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5753 * allows us to avoid some pointer chasing select_idle_sibling().
5755 * Also keep a unique ID per domain (we use the first cpu number in
5756 * the cpumask of the domain), this allows us to quickly tell if
5757 * two cpus are in the same cache domain, see cpus_share_cache().
5759 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5760 DEFINE_PER_CPU(int, sd_llc_id
);
5762 static void update_top_cache_domain(int cpu
)
5764 struct sched_domain
*sd
;
5767 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5769 id
= cpumask_first(sched_domain_span(sd
));
5771 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5772 per_cpu(sd_llc_id
, cpu
) = id
;
5776 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5777 * hold the hotplug lock.
5780 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5782 struct rq
*rq
= cpu_rq(cpu
);
5783 struct sched_domain
*tmp
;
5785 /* Remove the sched domains which do not contribute to scheduling. */
5786 for (tmp
= sd
; tmp
; ) {
5787 struct sched_domain
*parent
= tmp
->parent
;
5791 if (sd_parent_degenerate(tmp
, parent
)) {
5792 tmp
->parent
= parent
->parent
;
5794 parent
->parent
->child
= tmp
;
5795 destroy_sched_domain(parent
, cpu
);
5800 if (sd
&& sd_degenerate(sd
)) {
5803 destroy_sched_domain(tmp
, cpu
);
5808 sched_domain_debug(sd
, cpu
);
5810 rq_attach_root(rq
, rd
);
5812 rcu_assign_pointer(rq
->sd
, sd
);
5813 destroy_sched_domains(tmp
, cpu
);
5815 update_top_cache_domain(cpu
);
5818 /* cpus with isolated domains */
5819 static cpumask_var_t cpu_isolated_map
;
5821 /* Setup the mask of cpus configured for isolated domains */
5822 static int __init
isolated_cpu_setup(char *str
)
5824 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5825 cpulist_parse(str
, cpu_isolated_map
);
5829 __setup("isolcpus=", isolated_cpu_setup
);
5834 * find_next_best_node - find the next node to include in a sched_domain
5835 * @node: node whose sched_domain we're building
5836 * @used_nodes: nodes already in the sched_domain
5838 * Find the next node to include in a given scheduling domain. Simply
5839 * finds the closest node not already in the @used_nodes map.
5841 * Should use nodemask_t.
5843 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
5845 int i
, n
, val
, min_val
, best_node
= -1;
5849 for (i
= 0; i
< nr_node_ids
; i
++) {
5850 /* Start at @node */
5851 n
= (node
+ i
) % nr_node_ids
;
5853 if (!nr_cpus_node(n
))
5856 /* Skip already used nodes */
5857 if (node_isset(n
, *used_nodes
))
5860 /* Simple min distance search */
5861 val
= node_distance(node
, n
);
5863 if (val
< min_val
) {
5869 if (best_node
!= -1)
5870 node_set(best_node
, *used_nodes
);
5875 * sched_domain_node_span - get a cpumask for a node's sched_domain
5876 * @node: node whose cpumask we're constructing
5877 * @span: resulting cpumask
5879 * Given a node, construct a good cpumask for its sched_domain to span. It
5880 * should be one that prevents unnecessary balancing, but also spreads tasks
5883 static void sched_domain_node_span(int node
, struct cpumask
*span
)
5885 nodemask_t used_nodes
;
5888 cpumask_clear(span
);
5889 nodes_clear(used_nodes
);
5891 cpumask_or(span
, span
, cpumask_of_node(node
));
5892 node_set(node
, used_nodes
);
5894 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
5895 int next_node
= find_next_best_node(node
, &used_nodes
);
5898 cpumask_or(span
, span
, cpumask_of_node(next_node
));
5902 static const struct cpumask
*cpu_node_mask(int cpu
)
5904 lockdep_assert_held(&sched_domains_mutex
);
5906 sched_domain_node_span(cpu_to_node(cpu
), sched_domains_tmpmask
);
5908 return sched_domains_tmpmask
;
5911 static const struct cpumask
*cpu_allnodes_mask(int cpu
)
5913 return cpu_possible_mask
;
5915 #endif /* CONFIG_NUMA */
5917 static const struct cpumask
*cpu_cpu_mask(int cpu
)
5919 return cpumask_of_node(cpu_to_node(cpu
));
5922 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
5925 struct sched_domain
**__percpu sd
;
5926 struct sched_group
**__percpu sg
;
5927 struct sched_group_power
**__percpu sgp
;
5931 struct sched_domain
** __percpu sd
;
5932 struct root_domain
*rd
;
5942 struct sched_domain_topology_level
;
5944 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
5945 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
5947 #define SDTL_OVERLAP 0x01
5949 struct sched_domain_topology_level
{
5950 sched_domain_init_f init
;
5951 sched_domain_mask_f mask
;
5953 struct sd_data data
;
5957 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5959 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5960 const struct cpumask
*span
= sched_domain_span(sd
);
5961 struct cpumask
*covered
= sched_domains_tmpmask
;
5962 struct sd_data
*sdd
= sd
->private;
5963 struct sched_domain
*child
;
5966 cpumask_clear(covered
);
5968 for_each_cpu(i
, span
) {
5969 struct cpumask
*sg_span
;
5971 if (cpumask_test_cpu(i
, covered
))
5974 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5975 GFP_KERNEL
, cpu_to_node(cpu
));
5980 sg_span
= sched_group_cpus(sg
);
5982 child
= *per_cpu_ptr(sdd
->sd
, i
);
5984 child
= child
->child
;
5985 cpumask_copy(sg_span
, sched_domain_span(child
));
5987 cpumask_set_cpu(i
, sg_span
);
5989 cpumask_or(covered
, covered
, sg_span
);
5991 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, cpumask_first(sg_span
));
5992 atomic_inc(&sg
->sgp
->ref
);
5994 if (cpumask_test_cpu(cpu
, sg_span
))
6004 sd
->groups
= groups
;
6009 free_sched_groups(first
, 0);
6014 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
6016 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
6017 struct sched_domain
*child
= sd
->child
;
6020 cpu
= cpumask_first(sched_domain_span(child
));
6023 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
6024 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
6025 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
6032 * build_sched_groups will build a circular linked list of the groups
6033 * covered by the given span, and will set each group's ->cpumask correctly,
6034 * and ->cpu_power to 0.
6036 * Assumes the sched_domain tree is fully constructed
6039 build_sched_groups(struct sched_domain
*sd
, int cpu
)
6041 struct sched_group
*first
= NULL
, *last
= NULL
;
6042 struct sd_data
*sdd
= sd
->private;
6043 const struct cpumask
*span
= sched_domain_span(sd
);
6044 struct cpumask
*covered
;
6047 get_group(cpu
, sdd
, &sd
->groups
);
6048 atomic_inc(&sd
->groups
->ref
);
6050 if (cpu
!= cpumask_first(sched_domain_span(sd
)))
6053 lockdep_assert_held(&sched_domains_mutex
);
6054 covered
= sched_domains_tmpmask
;
6056 cpumask_clear(covered
);
6058 for_each_cpu(i
, span
) {
6059 struct sched_group
*sg
;
6060 int group
= get_group(i
, sdd
, &sg
);
6063 if (cpumask_test_cpu(i
, covered
))
6066 cpumask_clear(sched_group_cpus(sg
));
6069 for_each_cpu(j
, span
) {
6070 if (get_group(j
, sdd
, NULL
) != group
)
6073 cpumask_set_cpu(j
, covered
);
6074 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6089 * Initialize sched groups cpu_power.
6091 * cpu_power indicates the capacity of sched group, which is used while
6092 * distributing the load between different sched groups in a sched domain.
6093 * Typically cpu_power for all the groups in a sched domain will be same unless
6094 * there are asymmetries in the topology. If there are asymmetries, group
6095 * having more cpu_power will pickup more load compared to the group having
6098 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6100 struct sched_group
*sg
= sd
->groups
;
6102 WARN_ON(!sd
|| !sg
);
6105 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
6107 } while (sg
!= sd
->groups
);
6109 if (cpu
!= group_first_cpu(sg
))
6112 update_group_power(sd
, cpu
);
6113 atomic_set(&sg
->sgp
->nr_busy_cpus
, sg
->group_weight
);
6116 int __weak
arch_sd_sibling_asym_packing(void)
6118 return 0*SD_ASYM_PACKING
;
6122 * Initializers for schedule domains
6123 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6126 #ifdef CONFIG_SCHED_DEBUG
6127 # define SD_INIT_NAME(sd, type) sd->name = #type
6129 # define SD_INIT_NAME(sd, type) do { } while (0)
6132 #define SD_INIT_FUNC(type) \
6133 static noinline struct sched_domain * \
6134 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
6136 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
6137 *sd = SD_##type##_INIT; \
6138 SD_INIT_NAME(sd, type); \
6139 sd->private = &tl->data; \
6145 SD_INIT_FUNC(ALLNODES
)
6148 #ifdef CONFIG_SCHED_SMT
6149 SD_INIT_FUNC(SIBLING
)
6151 #ifdef CONFIG_SCHED_MC
6154 #ifdef CONFIG_SCHED_BOOK
6158 static int default_relax_domain_level
= -1;
6159 int sched_domain_level_max
;
6161 static int __init
setup_relax_domain_level(char *str
)
6165 val
= simple_strtoul(str
, NULL
, 0);
6166 if (val
< sched_domain_level_max
)
6167 default_relax_domain_level
= val
;
6171 __setup("relax_domain_level=", setup_relax_domain_level
);
6173 static void set_domain_attribute(struct sched_domain
*sd
,
6174 struct sched_domain_attr
*attr
)
6178 if (!attr
|| attr
->relax_domain_level
< 0) {
6179 if (default_relax_domain_level
< 0)
6182 request
= default_relax_domain_level
;
6184 request
= attr
->relax_domain_level
;
6185 if (request
< sd
->level
) {
6186 /* turn off idle balance on this domain */
6187 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6189 /* turn on idle balance on this domain */
6190 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6194 static void __sdt_free(const struct cpumask
*cpu_map
);
6195 static int __sdt_alloc(const struct cpumask
*cpu_map
);
6197 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6198 const struct cpumask
*cpu_map
)
6202 if (!atomic_read(&d
->rd
->refcount
))
6203 free_rootdomain(&d
->rd
->rcu
); /* fall through */
6205 free_percpu(d
->sd
); /* fall through */
6207 __sdt_free(cpu_map
); /* fall through */
6213 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6214 const struct cpumask
*cpu_map
)
6216 memset(d
, 0, sizeof(*d
));
6218 if (__sdt_alloc(cpu_map
))
6219 return sa_sd_storage
;
6220 d
->sd
= alloc_percpu(struct sched_domain
*);
6222 return sa_sd_storage
;
6223 d
->rd
= alloc_rootdomain();
6226 return sa_rootdomain
;
6230 * NULL the sd_data elements we've used to build the sched_domain and
6231 * sched_group structure so that the subsequent __free_domain_allocs()
6232 * will not free the data we're using.
6234 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
6236 struct sd_data
*sdd
= sd
->private;
6238 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
6239 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
6241 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
6242 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
6244 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
6245 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
6248 #ifdef CONFIG_SCHED_SMT
6249 static const struct cpumask
*cpu_smt_mask(int cpu
)
6251 return topology_thread_cpumask(cpu
);
6256 * Topology list, bottom-up.
6258 static struct sched_domain_topology_level default_topology
[] = {
6259 #ifdef CONFIG_SCHED_SMT
6260 { sd_init_SIBLING
, cpu_smt_mask
, },
6262 #ifdef CONFIG_SCHED_MC
6263 { sd_init_MC
, cpu_coregroup_mask
, },
6265 #ifdef CONFIG_SCHED_BOOK
6266 { sd_init_BOOK
, cpu_book_mask
, },
6268 { sd_init_CPU
, cpu_cpu_mask
, },
6270 { sd_init_NODE
, cpu_node_mask
, SDTL_OVERLAP
, },
6271 { sd_init_ALLNODES
, cpu_allnodes_mask
, },
6276 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6278 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6280 struct sched_domain_topology_level
*tl
;
6283 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6284 struct sd_data
*sdd
= &tl
->data
;
6286 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6290 sdd
->sg
= alloc_percpu(struct sched_group
*);
6294 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
6298 for_each_cpu(j
, cpu_map
) {
6299 struct sched_domain
*sd
;
6300 struct sched_group
*sg
;
6301 struct sched_group_power
*sgp
;
6303 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6304 GFP_KERNEL
, cpu_to_node(j
));
6308 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6310 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6311 GFP_KERNEL
, cpu_to_node(j
));
6315 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6317 sgp
= kzalloc_node(sizeof(struct sched_group_power
),
6318 GFP_KERNEL
, cpu_to_node(j
));
6322 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
6329 static void __sdt_free(const struct cpumask
*cpu_map
)
6331 struct sched_domain_topology_level
*tl
;
6334 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6335 struct sd_data
*sdd
= &tl
->data
;
6337 for_each_cpu(j
, cpu_map
) {
6338 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, j
);
6339 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6340 free_sched_groups(sd
->groups
, 0);
6341 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6342 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6343 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
6345 free_percpu(sdd
->sd
);
6346 free_percpu(sdd
->sg
);
6347 free_percpu(sdd
->sgp
);
6351 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6352 struct s_data
*d
, const struct cpumask
*cpu_map
,
6353 struct sched_domain_attr
*attr
, struct sched_domain
*child
,
6356 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
6360 set_domain_attribute(sd
, attr
);
6361 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6363 sd
->level
= child
->level
+ 1;
6364 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6373 * Build sched domains for a given set of cpus and attach the sched domains
6374 * to the individual cpus
6376 static int build_sched_domains(const struct cpumask
*cpu_map
,
6377 struct sched_domain_attr
*attr
)
6379 enum s_alloc alloc_state
= sa_none
;
6380 struct sched_domain
*sd
;
6382 int i
, ret
= -ENOMEM
;
6384 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6385 if (alloc_state
!= sa_rootdomain
)
6388 /* Set up domains for cpus specified by the cpu_map. */
6389 for_each_cpu(i
, cpu_map
) {
6390 struct sched_domain_topology_level
*tl
;
6393 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6394 sd
= build_sched_domain(tl
, &d
, cpu_map
, attr
, sd
, i
);
6395 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6396 sd
->flags
|= SD_OVERLAP
;
6397 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6404 *per_cpu_ptr(d
.sd
, i
) = sd
;
6407 /* Build the groups for the domains */
6408 for_each_cpu(i
, cpu_map
) {
6409 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6410 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6411 if (sd
->flags
& SD_OVERLAP
) {
6412 if (build_overlap_sched_groups(sd
, i
))
6415 if (build_sched_groups(sd
, i
))
6421 /* Calculate CPU power for physical packages and nodes */
6422 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6423 if (!cpumask_test_cpu(i
, cpu_map
))
6426 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6427 claim_allocations(i
, sd
);
6428 init_sched_groups_power(i
, sd
);
6432 /* Attach the domains */
6434 for_each_cpu(i
, cpu_map
) {
6435 sd
= *per_cpu_ptr(d
.sd
, i
);
6436 cpu_attach_domain(sd
, d
.rd
, i
);
6442 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6446 static cpumask_var_t
*doms_cur
; /* current sched domains */
6447 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6448 static struct sched_domain_attr
*dattr_cur
;
6449 /* attribues of custom domains in 'doms_cur' */
6452 * Special case: If a kmalloc of a doms_cur partition (array of
6453 * cpumask) fails, then fallback to a single sched domain,
6454 * as determined by the single cpumask fallback_doms.
6456 static cpumask_var_t fallback_doms
;
6459 * arch_update_cpu_topology lets virtualized architectures update the
6460 * cpu core maps. It is supposed to return 1 if the topology changed
6461 * or 0 if it stayed the same.
6463 int __attribute__((weak
)) arch_update_cpu_topology(void)
6468 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6471 cpumask_var_t
*doms
;
6473 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6476 for (i
= 0; i
< ndoms
; i
++) {
6477 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6478 free_sched_domains(doms
, i
);
6485 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6488 for (i
= 0; i
< ndoms
; i
++)
6489 free_cpumask_var(doms
[i
]);
6494 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6495 * For now this just excludes isolated cpus, but could be used to
6496 * exclude other special cases in the future.
6498 static int init_sched_domains(const struct cpumask
*cpu_map
)
6502 arch_update_cpu_topology();
6504 doms_cur
= alloc_sched_domains(ndoms_cur
);
6506 doms_cur
= &fallback_doms
;
6507 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6509 err
= build_sched_domains(doms_cur
[0], NULL
);
6510 register_sched_domain_sysctl();
6516 * Detach sched domains from a group of cpus specified in cpu_map
6517 * These cpus will now be attached to the NULL domain
6519 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6524 for_each_cpu(i
, cpu_map
)
6525 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6529 /* handle null as "default" */
6530 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6531 struct sched_domain_attr
*new, int idx_new
)
6533 struct sched_domain_attr tmp
;
6540 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6541 new ? (new + idx_new
) : &tmp
,
6542 sizeof(struct sched_domain_attr
));
6546 * Partition sched domains as specified by the 'ndoms_new'
6547 * cpumasks in the array doms_new[] of cpumasks. This compares
6548 * doms_new[] to the current sched domain partitioning, doms_cur[].
6549 * It destroys each deleted domain and builds each new domain.
6551 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6552 * The masks don't intersect (don't overlap.) We should setup one
6553 * sched domain for each mask. CPUs not in any of the cpumasks will
6554 * not be load balanced. If the same cpumask appears both in the
6555 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6558 * The passed in 'doms_new' should be allocated using
6559 * alloc_sched_domains. This routine takes ownership of it and will
6560 * free_sched_domains it when done with it. If the caller failed the
6561 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6562 * and partition_sched_domains() will fallback to the single partition
6563 * 'fallback_doms', it also forces the domains to be rebuilt.
6565 * If doms_new == NULL it will be replaced with cpu_online_mask.
6566 * ndoms_new == 0 is a special case for destroying existing domains,
6567 * and it will not create the default domain.
6569 * Call with hotplug lock held
6571 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6572 struct sched_domain_attr
*dattr_new
)
6577 mutex_lock(&sched_domains_mutex
);
6579 /* always unregister in case we don't destroy any domains */
6580 unregister_sched_domain_sysctl();
6582 /* Let architecture update cpu core mappings. */
6583 new_topology
= arch_update_cpu_topology();
6585 n
= doms_new
? ndoms_new
: 0;
6587 /* Destroy deleted domains */
6588 for (i
= 0; i
< ndoms_cur
; i
++) {
6589 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6590 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6591 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6594 /* no match - a current sched domain not in new doms_new[] */
6595 detach_destroy_domains(doms_cur
[i
]);
6600 if (doms_new
== NULL
) {
6602 doms_new
= &fallback_doms
;
6603 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6604 WARN_ON_ONCE(dattr_new
);
6607 /* Build new domains */
6608 for (i
= 0; i
< ndoms_new
; i
++) {
6609 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
6610 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6611 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6614 /* no match - add a new doms_new */
6615 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6620 /* Remember the new sched domains */
6621 if (doms_cur
!= &fallback_doms
)
6622 free_sched_domains(doms_cur
, ndoms_cur
);
6623 kfree(dattr_cur
); /* kfree(NULL) is safe */
6624 doms_cur
= doms_new
;
6625 dattr_cur
= dattr_new
;
6626 ndoms_cur
= ndoms_new
;
6628 register_sched_domain_sysctl();
6630 mutex_unlock(&sched_domains_mutex
);
6633 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
6634 static void reinit_sched_domains(void)
6638 /* Destroy domains first to force the rebuild */
6639 partition_sched_domains(0, NULL
, NULL
);
6641 rebuild_sched_domains();
6645 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
6647 unsigned int level
= 0;
6649 if (sscanf(buf
, "%u", &level
) != 1)
6653 * level is always be positive so don't check for
6654 * level < POWERSAVINGS_BALANCE_NONE which is 0
6655 * What happens on 0 or 1 byte write,
6656 * need to check for count as well?
6659 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
6663 sched_smt_power_savings
= level
;
6665 sched_mc_power_savings
= level
;
6667 reinit_sched_domains();
6672 #ifdef CONFIG_SCHED_MC
6673 static ssize_t
sched_mc_power_savings_show(struct device
*dev
,
6674 struct device_attribute
*attr
,
6677 return sprintf(buf
, "%u\n", sched_mc_power_savings
);
6679 static ssize_t
sched_mc_power_savings_store(struct device
*dev
,
6680 struct device_attribute
*attr
,
6681 const char *buf
, size_t count
)
6683 return sched_power_savings_store(buf
, count
, 0);
6685 static DEVICE_ATTR(sched_mc_power_savings
, 0644,
6686 sched_mc_power_savings_show
,
6687 sched_mc_power_savings_store
);
6690 #ifdef CONFIG_SCHED_SMT
6691 static ssize_t
sched_smt_power_savings_show(struct device
*dev
,
6692 struct device_attribute
*attr
,
6695 return sprintf(buf
, "%u\n", sched_smt_power_savings
);
6697 static ssize_t
sched_smt_power_savings_store(struct device
*dev
,
6698 struct device_attribute
*attr
,
6699 const char *buf
, size_t count
)
6701 return sched_power_savings_store(buf
, count
, 1);
6703 static DEVICE_ATTR(sched_smt_power_savings
, 0644,
6704 sched_smt_power_savings_show
,
6705 sched_smt_power_savings_store
);
6708 int __init
sched_create_sysfs_power_savings_entries(struct device
*dev
)
6712 #ifdef CONFIG_SCHED_SMT
6714 err
= device_create_file(dev
, &dev_attr_sched_smt_power_savings
);
6716 #ifdef CONFIG_SCHED_MC
6717 if (!err
&& mc_capable())
6718 err
= device_create_file(dev
, &dev_attr_sched_mc_power_savings
);
6722 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
6725 * Update cpusets according to cpu_active mask. If cpusets are
6726 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6727 * around partition_sched_domains().
6729 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6732 switch (action
& ~CPU_TASKS_FROZEN
) {
6734 case CPU_DOWN_FAILED
:
6735 cpuset_update_active_cpus();
6742 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6745 switch (action
& ~CPU_TASKS_FROZEN
) {
6746 case CPU_DOWN_PREPARE
:
6747 cpuset_update_active_cpus();
6754 void __init
sched_init_smp(void)
6756 cpumask_var_t non_isolated_cpus
;
6758 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6759 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6762 mutex_lock(&sched_domains_mutex
);
6763 init_sched_domains(cpu_active_mask
);
6764 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6765 if (cpumask_empty(non_isolated_cpus
))
6766 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6767 mutex_unlock(&sched_domains_mutex
);
6770 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6771 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6773 /* RT runtime code needs to handle some hotplug events */
6774 hotcpu_notifier(update_runtime
, 0);
6778 /* Move init over to a non-isolated CPU */
6779 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6781 sched_init_granularity();
6782 free_cpumask_var(non_isolated_cpus
);
6784 init_sched_rt_class();
6787 void __init
sched_init_smp(void)
6789 sched_init_granularity();
6791 #endif /* CONFIG_SMP */
6793 const_debug
unsigned int sysctl_timer_migration
= 1;
6795 int in_sched_functions(unsigned long addr
)
6797 return in_lock_functions(addr
) ||
6798 (addr
>= (unsigned long)__sched_text_start
6799 && addr
< (unsigned long)__sched_text_end
);
6802 #ifdef CONFIG_CGROUP_SCHED
6803 struct task_group root_task_group
;
6806 DECLARE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
6808 void __init
sched_init(void)
6811 unsigned long alloc_size
= 0, ptr
;
6813 #ifdef CONFIG_FAIR_GROUP_SCHED
6814 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6816 #ifdef CONFIG_RT_GROUP_SCHED
6817 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6819 #ifdef CONFIG_CPUMASK_OFFSTACK
6820 alloc_size
+= num_possible_cpus() * cpumask_size();
6823 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6825 #ifdef CONFIG_FAIR_GROUP_SCHED
6826 root_task_group
.se
= (struct sched_entity
**)ptr
;
6827 ptr
+= nr_cpu_ids
* sizeof(void **);
6829 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6830 ptr
+= nr_cpu_ids
* sizeof(void **);
6832 #endif /* CONFIG_FAIR_GROUP_SCHED */
6833 #ifdef CONFIG_RT_GROUP_SCHED
6834 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6835 ptr
+= nr_cpu_ids
* sizeof(void **);
6837 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6838 ptr
+= nr_cpu_ids
* sizeof(void **);
6840 #endif /* CONFIG_RT_GROUP_SCHED */
6841 #ifdef CONFIG_CPUMASK_OFFSTACK
6842 for_each_possible_cpu(i
) {
6843 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
6844 ptr
+= cpumask_size();
6846 #endif /* CONFIG_CPUMASK_OFFSTACK */
6850 init_defrootdomain();
6853 init_rt_bandwidth(&def_rt_bandwidth
,
6854 global_rt_period(), global_rt_runtime());
6856 #ifdef CONFIG_RT_GROUP_SCHED
6857 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6858 global_rt_period(), global_rt_runtime());
6859 #endif /* CONFIG_RT_GROUP_SCHED */
6861 #ifdef CONFIG_CGROUP_SCHED
6862 list_add(&root_task_group
.list
, &task_groups
);
6863 INIT_LIST_HEAD(&root_task_group
.children
);
6864 INIT_LIST_HEAD(&root_task_group
.siblings
);
6865 autogroup_init(&init_task
);
6867 #endif /* CONFIG_CGROUP_SCHED */
6869 #ifdef CONFIG_CGROUP_CPUACCT
6870 root_cpuacct
.cpustat
= &kernel_cpustat
;
6871 root_cpuacct
.cpuusage
= alloc_percpu(u64
);
6872 /* Too early, not expected to fail */
6873 BUG_ON(!root_cpuacct
.cpuusage
);
6875 for_each_possible_cpu(i
) {
6879 raw_spin_lock_init(&rq
->lock
);
6881 rq
->calc_load_active
= 0;
6882 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6883 init_cfs_rq(&rq
->cfs
);
6884 init_rt_rq(&rq
->rt
, rq
);
6885 #ifdef CONFIG_FAIR_GROUP_SCHED
6886 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6887 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6889 * How much cpu bandwidth does root_task_group get?
6891 * In case of task-groups formed thr' the cgroup filesystem, it
6892 * gets 100% of the cpu resources in the system. This overall
6893 * system cpu resource is divided among the tasks of
6894 * root_task_group and its child task-groups in a fair manner,
6895 * based on each entity's (task or task-group's) weight
6896 * (se->load.weight).
6898 * In other words, if root_task_group has 10 tasks of weight
6899 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6900 * then A0's share of the cpu resource is:
6902 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6904 * We achieve this by letting root_task_group's tasks sit
6905 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6907 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6908 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6909 #endif /* CONFIG_FAIR_GROUP_SCHED */
6911 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6912 #ifdef CONFIG_RT_GROUP_SCHED
6913 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
6914 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6917 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6918 rq
->cpu_load
[j
] = 0;
6920 rq
->last_load_update_tick
= jiffies
;
6925 rq
->cpu_power
= SCHED_POWER_SCALE
;
6926 rq
->post_schedule
= 0;
6927 rq
->active_balance
= 0;
6928 rq
->next_balance
= jiffies
;
6933 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
6934 rq_attach_root(rq
, &def_root_domain
);
6940 atomic_set(&rq
->nr_iowait
, 0);
6943 set_load_weight(&init_task
);
6945 #ifdef CONFIG_PREEMPT_NOTIFIERS
6946 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
6949 #ifdef CONFIG_RT_MUTEXES
6950 plist_head_init(&init_task
.pi_waiters
);
6954 * The boot idle thread does lazy MMU switching as well:
6956 atomic_inc(&init_mm
.mm_count
);
6957 enter_lazy_tlb(&init_mm
, current
);
6960 * Make us the idle thread. Technically, schedule() should not be
6961 * called from this thread, however somewhere below it might be,
6962 * but because we are the idle thread, we just pick up running again
6963 * when this runqueue becomes "idle".
6965 init_idle(current
, smp_processor_id());
6967 calc_load_update
= jiffies
+ LOAD_FREQ
;
6970 * During early bootup we pretend to be a normal task:
6972 current
->sched_class
= &fair_sched_class
;
6975 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
6976 /* May be allocated at isolcpus cmdline parse time */
6977 if (cpu_isolated_map
== NULL
)
6978 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
6980 init_sched_fair_class();
6982 scheduler_running
= 1;
6985 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6986 static inline int preempt_count_equals(int preempt_offset
)
6988 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
6990 return (nested
== preempt_offset
);
6993 void __might_sleep(const char *file
, int line
, int preempt_offset
)
6995 static unsigned long prev_jiffy
; /* ratelimiting */
6997 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
6998 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
6999 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7001 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7003 prev_jiffy
= jiffies
;
7006 "BUG: sleeping function called from invalid context at %s:%d\n",
7009 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7010 in_atomic(), irqs_disabled(),
7011 current
->pid
, current
->comm
);
7013 debug_show_held_locks(current
);
7014 if (irqs_disabled())
7015 print_irqtrace_events(current
);
7018 EXPORT_SYMBOL(__might_sleep
);
7021 #ifdef CONFIG_MAGIC_SYSRQ
7022 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7024 const struct sched_class
*prev_class
= p
->sched_class
;
7025 int old_prio
= p
->prio
;
7030 dequeue_task(rq
, p
, 0);
7031 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7033 enqueue_task(rq
, p
, 0);
7034 resched_task(rq
->curr
);
7037 check_class_changed(rq
, p
, prev_class
, old_prio
);
7040 void normalize_rt_tasks(void)
7042 struct task_struct
*g
, *p
;
7043 unsigned long flags
;
7046 read_lock_irqsave(&tasklist_lock
, flags
);
7047 do_each_thread(g
, p
) {
7049 * Only normalize user tasks:
7054 p
->se
.exec_start
= 0;
7055 #ifdef CONFIG_SCHEDSTATS
7056 p
->se
.statistics
.wait_start
= 0;
7057 p
->se
.statistics
.sleep_start
= 0;
7058 p
->se
.statistics
.block_start
= 0;
7063 * Renice negative nice level userspace
7066 if (TASK_NICE(p
) < 0 && p
->mm
)
7067 set_user_nice(p
, 0);
7071 raw_spin_lock(&p
->pi_lock
);
7072 rq
= __task_rq_lock(p
);
7074 normalize_task(rq
, p
);
7076 __task_rq_unlock(rq
);
7077 raw_spin_unlock(&p
->pi_lock
);
7078 } while_each_thread(g
, p
);
7080 read_unlock_irqrestore(&tasklist_lock
, flags
);
7083 #endif /* CONFIG_MAGIC_SYSRQ */
7085 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7087 * These functions are only useful for the IA64 MCA handling, or kdb.
7089 * They can only be called when the whole system has been
7090 * stopped - every CPU needs to be quiescent, and no scheduling
7091 * activity can take place. Using them for anything else would
7092 * be a serious bug, and as a result, they aren't even visible
7093 * under any other configuration.
7097 * curr_task - return the current task for a given cpu.
7098 * @cpu: the processor in question.
7100 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7102 struct task_struct
*curr_task(int cpu
)
7104 return cpu_curr(cpu
);
7107 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7111 * set_curr_task - set the current task for a given cpu.
7112 * @cpu: the processor in question.
7113 * @p: the task pointer to set.
7115 * Description: This function must only be used when non-maskable interrupts
7116 * are serviced on a separate stack. It allows the architecture to switch the
7117 * notion of the current task on a cpu in a non-blocking manner. This function
7118 * must be called with all CPU's synchronized, and interrupts disabled, the
7119 * and caller must save the original value of the current task (see
7120 * curr_task() above) and restore that value before reenabling interrupts and
7121 * re-starting the system.
7123 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7125 void set_curr_task(int cpu
, struct task_struct
*p
)
7132 #ifdef CONFIG_CGROUP_SCHED
7133 /* task_group_lock serializes the addition/removal of task groups */
7134 static DEFINE_SPINLOCK(task_group_lock
);
7136 static void free_sched_group(struct task_group
*tg
)
7138 free_fair_sched_group(tg
);
7139 free_rt_sched_group(tg
);
7144 /* allocate runqueue etc for a new task group */
7145 struct task_group
*sched_create_group(struct task_group
*parent
)
7147 struct task_group
*tg
;
7148 unsigned long flags
;
7150 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7152 return ERR_PTR(-ENOMEM
);
7154 if (!alloc_fair_sched_group(tg
, parent
))
7157 if (!alloc_rt_sched_group(tg
, parent
))
7160 spin_lock_irqsave(&task_group_lock
, flags
);
7161 list_add_rcu(&tg
->list
, &task_groups
);
7163 WARN_ON(!parent
); /* root should already exist */
7165 tg
->parent
= parent
;
7166 INIT_LIST_HEAD(&tg
->children
);
7167 list_add_rcu(&tg
->siblings
, &parent
->children
);
7168 spin_unlock_irqrestore(&task_group_lock
, flags
);
7173 free_sched_group(tg
);
7174 return ERR_PTR(-ENOMEM
);
7177 /* rcu callback to free various structures associated with a task group */
7178 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7180 /* now it should be safe to free those cfs_rqs */
7181 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7184 /* Destroy runqueue etc associated with a task group */
7185 void sched_destroy_group(struct task_group
*tg
)
7187 unsigned long flags
;
7190 /* end participation in shares distribution */
7191 for_each_possible_cpu(i
)
7192 unregister_fair_sched_group(tg
, i
);
7194 spin_lock_irqsave(&task_group_lock
, flags
);
7195 list_del_rcu(&tg
->list
);
7196 list_del_rcu(&tg
->siblings
);
7197 spin_unlock_irqrestore(&task_group_lock
, flags
);
7199 /* wait for possible concurrent references to cfs_rqs complete */
7200 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7203 /* change task's runqueue when it moves between groups.
7204 * The caller of this function should have put the task in its new group
7205 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7206 * reflect its new group.
7208 void sched_move_task(struct task_struct
*tsk
)
7211 unsigned long flags
;
7214 rq
= task_rq_lock(tsk
, &flags
);
7216 running
= task_current(rq
, tsk
);
7220 dequeue_task(rq
, tsk
, 0);
7221 if (unlikely(running
))
7222 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7224 #ifdef CONFIG_FAIR_GROUP_SCHED
7225 if (tsk
->sched_class
->task_move_group
)
7226 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
7229 set_task_rq(tsk
, task_cpu(tsk
));
7231 if (unlikely(running
))
7232 tsk
->sched_class
->set_curr_task(rq
);
7234 enqueue_task(rq
, tsk
, 0);
7236 task_rq_unlock(rq
, tsk
, &flags
);
7238 #endif /* CONFIG_CGROUP_SCHED */
7240 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
7241 static unsigned long to_ratio(u64 period
, u64 runtime
)
7243 if (runtime
== RUNTIME_INF
)
7246 return div64_u64(runtime
<< 20, period
);
7250 #ifdef CONFIG_RT_GROUP_SCHED
7252 * Ensure that the real time constraints are schedulable.
7254 static DEFINE_MUTEX(rt_constraints_mutex
);
7256 /* Must be called with tasklist_lock held */
7257 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7259 struct task_struct
*g
, *p
;
7261 do_each_thread(g
, p
) {
7262 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
7264 } while_each_thread(g
, p
);
7269 struct rt_schedulable_data
{
7270 struct task_group
*tg
;
7275 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7277 struct rt_schedulable_data
*d
= data
;
7278 struct task_group
*child
;
7279 unsigned long total
, sum
= 0;
7280 u64 period
, runtime
;
7282 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7283 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7286 period
= d
->rt_period
;
7287 runtime
= d
->rt_runtime
;
7291 * Cannot have more runtime than the period.
7293 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7297 * Ensure we don't starve existing RT tasks.
7299 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7302 total
= to_ratio(period
, runtime
);
7305 * Nobody can have more than the global setting allows.
7307 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7311 * The sum of our children's runtime should not exceed our own.
7313 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7314 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7315 runtime
= child
->rt_bandwidth
.rt_runtime
;
7317 if (child
== d
->tg
) {
7318 period
= d
->rt_period
;
7319 runtime
= d
->rt_runtime
;
7322 sum
+= to_ratio(period
, runtime
);
7331 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7335 struct rt_schedulable_data data
= {
7337 .rt_period
= period
,
7338 .rt_runtime
= runtime
,
7342 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7348 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7349 u64 rt_period
, u64 rt_runtime
)
7353 mutex_lock(&rt_constraints_mutex
);
7354 read_lock(&tasklist_lock
);
7355 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7359 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7360 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7361 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7363 for_each_possible_cpu(i
) {
7364 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7366 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7367 rt_rq
->rt_runtime
= rt_runtime
;
7368 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7370 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7372 read_unlock(&tasklist_lock
);
7373 mutex_unlock(&rt_constraints_mutex
);
7378 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7380 u64 rt_runtime
, rt_period
;
7382 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7383 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7384 if (rt_runtime_us
< 0)
7385 rt_runtime
= RUNTIME_INF
;
7387 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7390 long sched_group_rt_runtime(struct task_group
*tg
)
7394 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7397 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7398 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7399 return rt_runtime_us
;
7402 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7404 u64 rt_runtime
, rt_period
;
7406 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7407 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7412 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7415 long sched_group_rt_period(struct task_group
*tg
)
7419 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7420 do_div(rt_period_us
, NSEC_PER_USEC
);
7421 return rt_period_us
;
7424 static int sched_rt_global_constraints(void)
7426 u64 runtime
, period
;
7429 if (sysctl_sched_rt_period
<= 0)
7432 runtime
= global_rt_runtime();
7433 period
= global_rt_period();
7436 * Sanity check on the sysctl variables.
7438 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7441 mutex_lock(&rt_constraints_mutex
);
7442 read_lock(&tasklist_lock
);
7443 ret
= __rt_schedulable(NULL
, 0, 0);
7444 read_unlock(&tasklist_lock
);
7445 mutex_unlock(&rt_constraints_mutex
);
7450 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7452 /* Don't accept realtime tasks when there is no way for them to run */
7453 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7459 #else /* !CONFIG_RT_GROUP_SCHED */
7460 static int sched_rt_global_constraints(void)
7462 unsigned long flags
;
7465 if (sysctl_sched_rt_period
<= 0)
7469 * There's always some RT tasks in the root group
7470 * -- migration, kstopmachine etc..
7472 if (sysctl_sched_rt_runtime
== 0)
7475 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7476 for_each_possible_cpu(i
) {
7477 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7479 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7480 rt_rq
->rt_runtime
= global_rt_runtime();
7481 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7483 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7487 #endif /* CONFIG_RT_GROUP_SCHED */
7489 int sched_rt_handler(struct ctl_table
*table
, int write
,
7490 void __user
*buffer
, size_t *lenp
,
7494 int old_period
, old_runtime
;
7495 static DEFINE_MUTEX(mutex
);
7498 old_period
= sysctl_sched_rt_period
;
7499 old_runtime
= sysctl_sched_rt_runtime
;
7501 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7503 if (!ret
&& write
) {
7504 ret
= sched_rt_global_constraints();
7506 sysctl_sched_rt_period
= old_period
;
7507 sysctl_sched_rt_runtime
= old_runtime
;
7509 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7510 def_rt_bandwidth
.rt_period
=
7511 ns_to_ktime(global_rt_period());
7514 mutex_unlock(&mutex
);
7519 #ifdef CONFIG_CGROUP_SCHED
7521 /* return corresponding task_group object of a cgroup */
7522 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
7524 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
7525 struct task_group
, css
);
7528 static struct cgroup_subsys_state
*
7529 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
7531 struct task_group
*tg
, *parent
;
7533 if (!cgrp
->parent
) {
7534 /* This is early initialization for the top cgroup */
7535 return &root_task_group
.css
;
7538 parent
= cgroup_tg(cgrp
->parent
);
7539 tg
= sched_create_group(parent
);
7541 return ERR_PTR(-ENOMEM
);
7547 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
7549 struct task_group
*tg
= cgroup_tg(cgrp
);
7551 sched_destroy_group(tg
);
7554 static int cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
7555 struct cgroup_taskset
*tset
)
7557 struct task_struct
*task
;
7559 cgroup_taskset_for_each(task
, cgrp
, tset
) {
7560 #ifdef CONFIG_RT_GROUP_SCHED
7561 if (!sched_rt_can_attach(cgroup_tg(cgrp
), task
))
7564 /* We don't support RT-tasks being in separate groups */
7565 if (task
->sched_class
!= &fair_sched_class
)
7572 static void cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
7573 struct cgroup_taskset
*tset
)
7575 struct task_struct
*task
;
7577 cgroup_taskset_for_each(task
, cgrp
, tset
)
7578 sched_move_task(task
);
7582 cpu_cgroup_exit(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
7583 struct cgroup
*old_cgrp
, struct task_struct
*task
)
7586 * cgroup_exit() is called in the copy_process() failure path.
7587 * Ignore this case since the task hasn't ran yet, this avoids
7588 * trying to poke a half freed task state from generic code.
7590 if (!(task
->flags
& PF_EXITING
))
7593 sched_move_task(task
);
7596 #ifdef CONFIG_FAIR_GROUP_SCHED
7597 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7600 return sched_group_set_shares(cgroup_tg(cgrp
), scale_load(shareval
));
7603 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7605 struct task_group
*tg
= cgroup_tg(cgrp
);
7607 return (u64
) scale_load_down(tg
->shares
);
7610 #ifdef CONFIG_CFS_BANDWIDTH
7611 static DEFINE_MUTEX(cfs_constraints_mutex
);
7613 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7614 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7616 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7618 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7620 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7621 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7623 if (tg
== &root_task_group
)
7627 * Ensure we have at some amount of bandwidth every period. This is
7628 * to prevent reaching a state of large arrears when throttled via
7629 * entity_tick() resulting in prolonged exit starvation.
7631 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7635 * Likewise, bound things on the otherside by preventing insane quota
7636 * periods. This also allows us to normalize in computing quota
7639 if (period
> max_cfs_quota_period
)
7642 mutex_lock(&cfs_constraints_mutex
);
7643 ret
= __cfs_schedulable(tg
, period
, quota
);
7647 runtime_enabled
= quota
!= RUNTIME_INF
;
7648 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7649 account_cfs_bandwidth_used(runtime_enabled
, runtime_was_enabled
);
7650 raw_spin_lock_irq(&cfs_b
->lock
);
7651 cfs_b
->period
= ns_to_ktime(period
);
7652 cfs_b
->quota
= quota
;
7654 __refill_cfs_bandwidth_runtime(cfs_b
);
7655 /* restart the period timer (if active) to handle new period expiry */
7656 if (runtime_enabled
&& cfs_b
->timer_active
) {
7657 /* force a reprogram */
7658 cfs_b
->timer_active
= 0;
7659 __start_cfs_bandwidth(cfs_b
);
7661 raw_spin_unlock_irq(&cfs_b
->lock
);
7663 for_each_possible_cpu(i
) {
7664 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7665 struct rq
*rq
= cfs_rq
->rq
;
7667 raw_spin_lock_irq(&rq
->lock
);
7668 cfs_rq
->runtime_enabled
= runtime_enabled
;
7669 cfs_rq
->runtime_remaining
= 0;
7671 if (cfs_rq
->throttled
)
7672 unthrottle_cfs_rq(cfs_rq
);
7673 raw_spin_unlock_irq(&rq
->lock
);
7676 mutex_unlock(&cfs_constraints_mutex
);
7681 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7685 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7686 if (cfs_quota_us
< 0)
7687 quota
= RUNTIME_INF
;
7689 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7691 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7694 long tg_get_cfs_quota(struct task_group
*tg
)
7698 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7701 quota_us
= tg
->cfs_bandwidth
.quota
;
7702 do_div(quota_us
, NSEC_PER_USEC
);
7707 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7711 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7712 quota
= tg
->cfs_bandwidth
.quota
;
7714 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7717 long tg_get_cfs_period(struct task_group
*tg
)
7721 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7722 do_div(cfs_period_us
, NSEC_PER_USEC
);
7724 return cfs_period_us
;
7727 static s64
cpu_cfs_quota_read_s64(struct cgroup
*cgrp
, struct cftype
*cft
)
7729 return tg_get_cfs_quota(cgroup_tg(cgrp
));
7732 static int cpu_cfs_quota_write_s64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7735 return tg_set_cfs_quota(cgroup_tg(cgrp
), cfs_quota_us
);
7738 static u64
cpu_cfs_period_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7740 return tg_get_cfs_period(cgroup_tg(cgrp
));
7743 static int cpu_cfs_period_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7746 return tg_set_cfs_period(cgroup_tg(cgrp
), cfs_period_us
);
7749 struct cfs_schedulable_data
{
7750 struct task_group
*tg
;
7755 * normalize group quota/period to be quota/max_period
7756 * note: units are usecs
7758 static u64
normalize_cfs_quota(struct task_group
*tg
,
7759 struct cfs_schedulable_data
*d
)
7767 period
= tg_get_cfs_period(tg
);
7768 quota
= tg_get_cfs_quota(tg
);
7771 /* note: these should typically be equivalent */
7772 if (quota
== RUNTIME_INF
|| quota
== -1)
7775 return to_ratio(period
, quota
);
7778 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7780 struct cfs_schedulable_data
*d
= data
;
7781 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7782 s64 quota
= 0, parent_quota
= -1;
7785 quota
= RUNTIME_INF
;
7787 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
7789 quota
= normalize_cfs_quota(tg
, d
);
7790 parent_quota
= parent_b
->hierarchal_quota
;
7793 * ensure max(child_quota) <= parent_quota, inherit when no
7796 if (quota
== RUNTIME_INF
)
7797 quota
= parent_quota
;
7798 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
7801 cfs_b
->hierarchal_quota
= quota
;
7806 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
7809 struct cfs_schedulable_data data
= {
7815 if (quota
!= RUNTIME_INF
) {
7816 do_div(data
.period
, NSEC_PER_USEC
);
7817 do_div(data
.quota
, NSEC_PER_USEC
);
7821 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
7827 static int cpu_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
7828 struct cgroup_map_cb
*cb
)
7830 struct task_group
*tg
= cgroup_tg(cgrp
);
7831 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7833 cb
->fill(cb
, "nr_periods", cfs_b
->nr_periods
);
7834 cb
->fill(cb
, "nr_throttled", cfs_b
->nr_throttled
);
7835 cb
->fill(cb
, "throttled_time", cfs_b
->throttled_time
);
7839 #endif /* CONFIG_CFS_BANDWIDTH */
7840 #endif /* CONFIG_FAIR_GROUP_SCHED */
7842 #ifdef CONFIG_RT_GROUP_SCHED
7843 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
7846 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
7849 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
7851 return sched_group_rt_runtime(cgroup_tg(cgrp
));
7854 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
7857 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
7860 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
7862 return sched_group_rt_period(cgroup_tg(cgrp
));
7864 #endif /* CONFIG_RT_GROUP_SCHED */
7866 static struct cftype cpu_files
[] = {
7867 #ifdef CONFIG_FAIR_GROUP_SCHED
7870 .read_u64
= cpu_shares_read_u64
,
7871 .write_u64
= cpu_shares_write_u64
,
7874 #ifdef CONFIG_CFS_BANDWIDTH
7876 .name
= "cfs_quota_us",
7877 .read_s64
= cpu_cfs_quota_read_s64
,
7878 .write_s64
= cpu_cfs_quota_write_s64
,
7881 .name
= "cfs_period_us",
7882 .read_u64
= cpu_cfs_period_read_u64
,
7883 .write_u64
= cpu_cfs_period_write_u64
,
7887 .read_map
= cpu_stats_show
,
7890 #ifdef CONFIG_RT_GROUP_SCHED
7892 .name
= "rt_runtime_us",
7893 .read_s64
= cpu_rt_runtime_read
,
7894 .write_s64
= cpu_rt_runtime_write
,
7897 .name
= "rt_period_us",
7898 .read_u64
= cpu_rt_period_read_uint
,
7899 .write_u64
= cpu_rt_period_write_uint
,
7904 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
7906 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
7909 struct cgroup_subsys cpu_cgroup_subsys
= {
7911 .create
= cpu_cgroup_create
,
7912 .destroy
= cpu_cgroup_destroy
,
7913 .can_attach
= cpu_cgroup_can_attach
,
7914 .attach
= cpu_cgroup_attach
,
7915 .exit
= cpu_cgroup_exit
,
7916 .populate
= cpu_cgroup_populate
,
7917 .subsys_id
= cpu_cgroup_subsys_id
,
7921 #endif /* CONFIG_CGROUP_SCHED */
7923 #ifdef CONFIG_CGROUP_CPUACCT
7926 * CPU accounting code for task groups.
7928 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
7929 * (balbir@in.ibm.com).
7932 /* create a new cpu accounting group */
7933 static struct cgroup_subsys_state
*cpuacct_create(
7934 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
7939 return &root_cpuacct
.css
;
7941 ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
7945 ca
->cpuusage
= alloc_percpu(u64
);
7949 ca
->cpustat
= alloc_percpu(struct kernel_cpustat
);
7951 goto out_free_cpuusage
;
7956 free_percpu(ca
->cpuusage
);
7960 return ERR_PTR(-ENOMEM
);
7963 /* destroy an existing cpu accounting group */
7965 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
7967 struct cpuacct
*ca
= cgroup_ca(cgrp
);
7969 free_percpu(ca
->cpustat
);
7970 free_percpu(ca
->cpuusage
);
7974 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
7976 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
7979 #ifndef CONFIG_64BIT
7981 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
7983 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
7985 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
7993 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
7995 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
7997 #ifndef CONFIG_64BIT
7999 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8001 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8003 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8009 /* return total cpu usage (in nanoseconds) of a group */
8010 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8012 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8013 u64 totalcpuusage
= 0;
8016 for_each_present_cpu(i
)
8017 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
8019 return totalcpuusage
;
8022 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8025 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8034 for_each_present_cpu(i
)
8035 cpuacct_cpuusage_write(ca
, i
, 0);
8041 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
8044 struct cpuacct
*ca
= cgroup_ca(cgroup
);
8048 for_each_present_cpu(i
) {
8049 percpu
= cpuacct_cpuusage_read(ca
, i
);
8050 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
8052 seq_printf(m
, "\n");
8056 static const char *cpuacct_stat_desc
[] = {
8057 [CPUACCT_STAT_USER
] = "user",
8058 [CPUACCT_STAT_SYSTEM
] = "system",
8061 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
8062 struct cgroup_map_cb
*cb
)
8064 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8068 for_each_online_cpu(cpu
) {
8069 struct kernel_cpustat
*kcpustat
= per_cpu_ptr(ca
->cpustat
, cpu
);
8070 val
+= kcpustat
->cpustat
[CPUTIME_USER
];
8071 val
+= kcpustat
->cpustat
[CPUTIME_NICE
];
8073 val
= cputime64_to_clock_t(val
);
8074 cb
->fill(cb
, cpuacct_stat_desc
[CPUACCT_STAT_USER
], val
);
8077 for_each_online_cpu(cpu
) {
8078 struct kernel_cpustat
*kcpustat
= per_cpu_ptr(ca
->cpustat
, cpu
);
8079 val
+= kcpustat
->cpustat
[CPUTIME_SYSTEM
];
8080 val
+= kcpustat
->cpustat
[CPUTIME_IRQ
];
8081 val
+= kcpustat
->cpustat
[CPUTIME_SOFTIRQ
];
8084 val
= cputime64_to_clock_t(val
);
8085 cb
->fill(cb
, cpuacct_stat_desc
[CPUACCT_STAT_SYSTEM
], val
);
8090 static struct cftype files
[] = {
8093 .read_u64
= cpuusage_read
,
8094 .write_u64
= cpuusage_write
,
8097 .name
= "usage_percpu",
8098 .read_seq_string
= cpuacct_percpu_seq_read
,
8102 .read_map
= cpuacct_stats_show
,
8106 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8108 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8112 * charge this task's execution time to its accounting group.
8114 * called with rq->lock held.
8116 void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8121 if (unlikely(!cpuacct_subsys
.active
))
8124 cpu
= task_cpu(tsk
);
8130 for (; ca
; ca
= parent_ca(ca
)) {
8131 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8132 *cpuusage
+= cputime
;
8138 struct cgroup_subsys cpuacct_subsys
= {
8140 .create
= cpuacct_create
,
8141 .destroy
= cpuacct_destroy
,
8142 .populate
= cpuacct_populate
,
8143 .subsys_id
= cpuacct_subsys_id
,
8145 #endif /* CONFIG_CGROUP_CPUACCT */