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 #ifdef CONFIG_PARAVIRT
78 #include <asm/paravirt.h>
82 #include "../workqueue_sched.h"
84 #define CREATE_TRACE_POINTS
85 #include <trace/events/sched.h>
87 void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
90 ktime_t soft
, hard
, now
;
93 if (hrtimer_active(period_timer
))
96 now
= hrtimer_cb_get_time(period_timer
);
97 hrtimer_forward(period_timer
, now
, period
);
99 soft
= hrtimer_get_softexpires(period_timer
);
100 hard
= hrtimer_get_expires(period_timer
);
101 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
102 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
103 HRTIMER_MODE_ABS_PINNED
, 0);
107 DEFINE_MUTEX(sched_domains_mutex
);
108 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
110 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
112 void update_rq_clock(struct rq
*rq
)
116 if (rq
->skip_clock_update
> 0)
119 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
121 update_rq_clock_task(rq
, delta
);
125 * Debugging: various feature bits
128 #define SCHED_FEAT(name, enabled) \
129 (1UL << __SCHED_FEAT_##name) * enabled |
131 const_debug
unsigned int sysctl_sched_features
=
132 #include "features.h"
137 #ifdef CONFIG_SCHED_DEBUG
138 #define SCHED_FEAT(name, enabled) \
141 static __read_mostly
char *sched_feat_names
[] = {
142 #include "features.h"
148 static int sched_feat_show(struct seq_file
*m
, void *v
)
152 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
153 if (!(sysctl_sched_features
& (1UL << i
)))
155 seq_printf(m
, "%s ", sched_feat_names
[i
]);
162 #ifdef HAVE_JUMP_LABEL
164 #define jump_label_key__true jump_label_key_enabled
165 #define jump_label_key__false jump_label_key_disabled
167 #define SCHED_FEAT(name, enabled) \
168 jump_label_key__##enabled ,
170 struct jump_label_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
171 #include "features.h"
176 static void sched_feat_disable(int i
)
178 if (jump_label_enabled(&sched_feat_keys
[i
]))
179 jump_label_dec(&sched_feat_keys
[i
]);
182 static void sched_feat_enable(int i
)
184 if (!jump_label_enabled(&sched_feat_keys
[i
]))
185 jump_label_inc(&sched_feat_keys
[i
]);
188 static void sched_feat_disable(int i
) { };
189 static void sched_feat_enable(int i
) { };
190 #endif /* HAVE_JUMP_LABEL */
193 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
194 size_t cnt
, loff_t
*ppos
)
204 if (copy_from_user(&buf
, ubuf
, cnt
))
210 if (strncmp(cmp
, "NO_", 3) == 0) {
215 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
216 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
218 sysctl_sched_features
&= ~(1UL << i
);
219 sched_feat_disable(i
);
221 sysctl_sched_features
|= (1UL << i
);
222 sched_feat_enable(i
);
228 if (i
== __SCHED_FEAT_NR
)
236 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
238 return single_open(filp
, sched_feat_show
, NULL
);
241 static const struct file_operations sched_feat_fops
= {
242 .open
= sched_feat_open
,
243 .write
= sched_feat_write
,
246 .release
= single_release
,
249 static __init
int sched_init_debug(void)
251 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
256 late_initcall(sched_init_debug
);
257 #endif /* CONFIG_SCHED_DEBUG */
260 * Number of tasks to iterate in a single balance run.
261 * Limited because this is done with IRQs disabled.
263 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
266 * period over which we average the RT time consumption, measured
271 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
274 * period over which we measure -rt task cpu usage in us.
277 unsigned int sysctl_sched_rt_period
= 1000000;
279 __read_mostly
int scheduler_running
;
282 * part of the period that we allow rt tasks to run in us.
285 int sysctl_sched_rt_runtime
= 950000;
290 * __task_rq_lock - lock the rq @p resides on.
292 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
297 lockdep_assert_held(&p
->pi_lock
);
301 raw_spin_lock(&rq
->lock
);
302 if (likely(rq
== task_rq(p
)))
304 raw_spin_unlock(&rq
->lock
);
309 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
311 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
312 __acquires(p
->pi_lock
)
318 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
320 raw_spin_lock(&rq
->lock
);
321 if (likely(rq
== task_rq(p
)))
323 raw_spin_unlock(&rq
->lock
);
324 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
328 static void __task_rq_unlock(struct rq
*rq
)
331 raw_spin_unlock(&rq
->lock
);
335 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
337 __releases(p
->pi_lock
)
339 raw_spin_unlock(&rq
->lock
);
340 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
344 * this_rq_lock - lock this runqueue and disable interrupts.
346 static struct rq
*this_rq_lock(void)
353 raw_spin_lock(&rq
->lock
);
358 #ifdef CONFIG_SCHED_HRTICK
360 * Use HR-timers to deliver accurate preemption points.
362 * Its all a bit involved since we cannot program an hrt while holding the
363 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
366 * When we get rescheduled we reprogram the hrtick_timer outside of the
370 static void hrtick_clear(struct rq
*rq
)
372 if (hrtimer_active(&rq
->hrtick_timer
))
373 hrtimer_cancel(&rq
->hrtick_timer
);
377 * High-resolution timer tick.
378 * Runs from hardirq context with interrupts disabled.
380 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
382 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
384 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
386 raw_spin_lock(&rq
->lock
);
388 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
389 raw_spin_unlock(&rq
->lock
);
391 return HRTIMER_NORESTART
;
396 * called from hardirq (IPI) context
398 static void __hrtick_start(void *arg
)
402 raw_spin_lock(&rq
->lock
);
403 hrtimer_restart(&rq
->hrtick_timer
);
404 rq
->hrtick_csd_pending
= 0;
405 raw_spin_unlock(&rq
->lock
);
409 * Called to set the hrtick timer state.
411 * called with rq->lock held and irqs disabled
413 void hrtick_start(struct rq
*rq
, u64 delay
)
415 struct hrtimer
*timer
= &rq
->hrtick_timer
;
416 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
418 hrtimer_set_expires(timer
, time
);
420 if (rq
== this_rq()) {
421 hrtimer_restart(timer
);
422 } else if (!rq
->hrtick_csd_pending
) {
423 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
424 rq
->hrtick_csd_pending
= 1;
429 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
431 int cpu
= (int)(long)hcpu
;
434 case CPU_UP_CANCELED
:
435 case CPU_UP_CANCELED_FROZEN
:
436 case CPU_DOWN_PREPARE
:
437 case CPU_DOWN_PREPARE_FROZEN
:
439 case CPU_DEAD_FROZEN
:
440 hrtick_clear(cpu_rq(cpu
));
447 static __init
void init_hrtick(void)
449 hotcpu_notifier(hotplug_hrtick
, 0);
453 * Called to set the hrtick timer state.
455 * called with rq->lock held and irqs disabled
457 void hrtick_start(struct rq
*rq
, u64 delay
)
459 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
460 HRTIMER_MODE_REL_PINNED
, 0);
463 static inline void init_hrtick(void)
466 #endif /* CONFIG_SMP */
468 static void init_rq_hrtick(struct rq
*rq
)
471 rq
->hrtick_csd_pending
= 0;
473 rq
->hrtick_csd
.flags
= 0;
474 rq
->hrtick_csd
.func
= __hrtick_start
;
475 rq
->hrtick_csd
.info
= rq
;
478 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
479 rq
->hrtick_timer
.function
= hrtick
;
481 #else /* CONFIG_SCHED_HRTICK */
482 static inline void hrtick_clear(struct rq
*rq
)
486 static inline void init_rq_hrtick(struct rq
*rq
)
490 static inline void init_hrtick(void)
493 #endif /* CONFIG_SCHED_HRTICK */
496 * resched_task - mark a task 'to be rescheduled now'.
498 * On UP this means the setting of the need_resched flag, on SMP it
499 * might also involve a cross-CPU call to trigger the scheduler on
504 #ifndef tsk_is_polling
505 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
508 void resched_task(struct task_struct
*p
)
512 assert_raw_spin_locked(&task_rq(p
)->lock
);
514 if (test_tsk_need_resched(p
))
517 set_tsk_need_resched(p
);
520 if (cpu
== smp_processor_id())
523 /* NEED_RESCHED must be visible before we test polling */
525 if (!tsk_is_polling(p
))
526 smp_send_reschedule(cpu
);
529 void resched_cpu(int cpu
)
531 struct rq
*rq
= cpu_rq(cpu
);
534 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
536 resched_task(cpu_curr(cpu
));
537 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
542 * In the semi idle case, use the nearest busy cpu for migrating timers
543 * from an idle cpu. This is good for power-savings.
545 * We don't do similar optimization for completely idle system, as
546 * selecting an idle cpu will add more delays to the timers than intended
547 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
549 int get_nohz_timer_target(void)
551 int cpu
= smp_processor_id();
553 struct sched_domain
*sd
;
556 for_each_domain(cpu
, sd
) {
557 for_each_cpu(i
, sched_domain_span(sd
)) {
569 * When add_timer_on() enqueues a timer into the timer wheel of an
570 * idle CPU then this timer might expire before the next timer event
571 * which is scheduled to wake up that CPU. In case of a completely
572 * idle system the next event might even be infinite time into the
573 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
574 * leaves the inner idle loop so the newly added timer is taken into
575 * account when the CPU goes back to idle and evaluates the timer
576 * wheel for the next timer event.
578 void wake_up_idle_cpu(int cpu
)
580 struct rq
*rq
= cpu_rq(cpu
);
582 if (cpu
== smp_processor_id())
586 * This is safe, as this function is called with the timer
587 * wheel base lock of (cpu) held. When the CPU is on the way
588 * to idle and has not yet set rq->curr to idle then it will
589 * be serialized on the timer wheel base lock and take the new
590 * timer into account automatically.
592 if (rq
->curr
!= rq
->idle
)
596 * We can set TIF_RESCHED on the idle task of the other CPU
597 * lockless. The worst case is that the other CPU runs the
598 * idle task through an additional NOOP schedule()
600 set_tsk_need_resched(rq
->idle
);
602 /* NEED_RESCHED must be visible before we test polling */
604 if (!tsk_is_polling(rq
->idle
))
605 smp_send_reschedule(cpu
);
608 static inline bool got_nohz_idle_kick(void)
610 int cpu
= smp_processor_id();
611 return idle_cpu(cpu
) && test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
614 #else /* CONFIG_NO_HZ */
616 static inline bool got_nohz_idle_kick(void)
621 #endif /* CONFIG_NO_HZ */
623 void sched_avg_update(struct rq
*rq
)
625 s64 period
= sched_avg_period();
627 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
629 * Inline assembly required to prevent the compiler
630 * optimising this loop into a divmod call.
631 * See __iter_div_u64_rem() for another example of this.
633 asm("" : "+rm" (rq
->age_stamp
));
634 rq
->age_stamp
+= period
;
639 #else /* !CONFIG_SMP */
640 void resched_task(struct task_struct
*p
)
642 assert_raw_spin_locked(&task_rq(p
)->lock
);
643 set_tsk_need_resched(p
);
645 #endif /* CONFIG_SMP */
647 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
648 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
650 * Iterate task_group tree rooted at *from, calling @down when first entering a
651 * node and @up when leaving it for the final time.
653 * Caller must hold rcu_lock or sufficient equivalent.
655 int walk_tg_tree_from(struct task_group
*from
,
656 tg_visitor down
, tg_visitor up
, void *data
)
658 struct task_group
*parent
, *child
;
664 ret
= (*down
)(parent
, data
);
667 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
674 ret
= (*up
)(parent
, data
);
675 if (ret
|| parent
== from
)
679 parent
= parent
->parent
;
686 int tg_nop(struct task_group
*tg
, void *data
)
692 void update_cpu_load(struct rq
*this_rq
);
694 static void set_load_weight(struct task_struct
*p
)
696 int prio
= p
->static_prio
- MAX_RT_PRIO
;
697 struct load_weight
*load
= &p
->se
.load
;
700 * SCHED_IDLE tasks get minimal weight:
702 if (p
->policy
== SCHED_IDLE
) {
703 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
704 load
->inv_weight
= WMULT_IDLEPRIO
;
708 load
->weight
= scale_load(prio_to_weight
[prio
]);
709 load
->inv_weight
= prio_to_wmult
[prio
];
712 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
715 sched_info_queued(p
);
716 p
->sched_class
->enqueue_task(rq
, p
, flags
);
719 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
722 sched_info_dequeued(p
);
723 p
->sched_class
->dequeue_task(rq
, p
, flags
);
727 * activate_task - move a task to the runqueue.
729 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
731 if (task_contributes_to_load(p
))
732 rq
->nr_uninterruptible
--;
734 enqueue_task(rq
, p
, flags
);
738 * deactivate_task - remove a task from the runqueue.
740 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
742 if (task_contributes_to_load(p
))
743 rq
->nr_uninterruptible
++;
745 dequeue_task(rq
, p
, flags
);
748 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
751 * There are no locks covering percpu hardirq/softirq time.
752 * They are only modified in account_system_vtime, on corresponding CPU
753 * with interrupts disabled. So, writes are safe.
754 * They are read and saved off onto struct rq in update_rq_clock().
755 * This may result in other CPU reading this CPU's irq time and can
756 * race with irq/account_system_vtime on this CPU. We would either get old
757 * or new value with a side effect of accounting a slice of irq time to wrong
758 * task when irq is in progress while we read rq->clock. That is a worthy
759 * compromise in place of having locks on each irq in account_system_time.
761 static DEFINE_PER_CPU(u64
, cpu_hardirq_time
);
762 static DEFINE_PER_CPU(u64
, cpu_softirq_time
);
764 static DEFINE_PER_CPU(u64
, irq_start_time
);
765 static int sched_clock_irqtime
;
767 void enable_sched_clock_irqtime(void)
769 sched_clock_irqtime
= 1;
772 void disable_sched_clock_irqtime(void)
774 sched_clock_irqtime
= 0;
778 static DEFINE_PER_CPU(seqcount_t
, irq_time_seq
);
780 static inline void irq_time_write_begin(void)
782 __this_cpu_inc(irq_time_seq
.sequence
);
786 static inline void irq_time_write_end(void)
789 __this_cpu_inc(irq_time_seq
.sequence
);
792 static inline u64
irq_time_read(int cpu
)
798 seq
= read_seqcount_begin(&per_cpu(irq_time_seq
, cpu
));
799 irq_time
= per_cpu(cpu_softirq_time
, cpu
) +
800 per_cpu(cpu_hardirq_time
, cpu
);
801 } while (read_seqcount_retry(&per_cpu(irq_time_seq
, cpu
), seq
));
805 #else /* CONFIG_64BIT */
806 static inline void irq_time_write_begin(void)
810 static inline void irq_time_write_end(void)
814 static inline u64
irq_time_read(int cpu
)
816 return per_cpu(cpu_softirq_time
, cpu
) + per_cpu(cpu_hardirq_time
, cpu
);
818 #endif /* CONFIG_64BIT */
821 * Called before incrementing preempt_count on {soft,}irq_enter
822 * and before decrementing preempt_count on {soft,}irq_exit.
824 void account_system_vtime(struct task_struct
*curr
)
830 if (!sched_clock_irqtime
)
833 local_irq_save(flags
);
835 cpu
= smp_processor_id();
836 delta
= sched_clock_cpu(cpu
) - __this_cpu_read(irq_start_time
);
837 __this_cpu_add(irq_start_time
, delta
);
839 irq_time_write_begin();
841 * We do not account for softirq time from ksoftirqd here.
842 * We want to continue accounting softirq time to ksoftirqd thread
843 * in that case, so as not to confuse scheduler with a special task
844 * that do not consume any time, but still wants to run.
847 __this_cpu_add(cpu_hardirq_time
, delta
);
848 else if (in_serving_softirq() && curr
!= this_cpu_ksoftirqd())
849 __this_cpu_add(cpu_softirq_time
, delta
);
851 irq_time_write_end();
852 local_irq_restore(flags
);
854 EXPORT_SYMBOL_GPL(account_system_vtime
);
856 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
858 #ifdef CONFIG_PARAVIRT
859 static inline u64
steal_ticks(u64 steal
)
861 if (unlikely(steal
> NSEC_PER_SEC
))
862 return div_u64(steal
, TICK_NSEC
);
864 return __iter_div_u64_rem(steal
, TICK_NSEC
, &steal
);
868 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
871 * In theory, the compile should just see 0 here, and optimize out the call
872 * to sched_rt_avg_update. But I don't trust it...
874 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
875 s64 steal
= 0, irq_delta
= 0;
877 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
878 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
881 * Since irq_time is only updated on {soft,}irq_exit, we might run into
882 * this case when a previous update_rq_clock() happened inside a
885 * When this happens, we stop ->clock_task and only update the
886 * prev_irq_time stamp to account for the part that fit, so that a next
887 * update will consume the rest. This ensures ->clock_task is
890 * It does however cause some slight miss-attribution of {soft,}irq
891 * time, a more accurate solution would be to update the irq_time using
892 * the current rq->clock timestamp, except that would require using
895 if (irq_delta
> delta
)
898 rq
->prev_irq_time
+= irq_delta
;
901 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
902 if (static_branch((¶virt_steal_rq_enabled
))) {
905 steal
= paravirt_steal_clock(cpu_of(rq
));
906 steal
-= rq
->prev_steal_time_rq
;
908 if (unlikely(steal
> delta
))
911 st
= steal_ticks(steal
);
912 steal
= st
* TICK_NSEC
;
914 rq
->prev_steal_time_rq
+= steal
;
920 rq
->clock_task
+= delta
;
922 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
923 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
924 sched_rt_avg_update(rq
, irq_delta
+ steal
);
928 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
929 static int irqtime_account_hi_update(void)
931 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
936 local_irq_save(flags
);
937 latest_ns
= this_cpu_read(cpu_hardirq_time
);
938 if (nsecs_to_cputime64(latest_ns
) > cpustat
[CPUTIME_IRQ
])
940 local_irq_restore(flags
);
944 static int irqtime_account_si_update(void)
946 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
951 local_irq_save(flags
);
952 latest_ns
= this_cpu_read(cpu_softirq_time
);
953 if (nsecs_to_cputime64(latest_ns
) > cpustat
[CPUTIME_SOFTIRQ
])
955 local_irq_restore(flags
);
959 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
961 #define sched_clock_irqtime (0)
965 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
967 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
968 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
972 * Make it appear like a SCHED_FIFO task, its something
973 * userspace knows about and won't get confused about.
975 * Also, it will make PI more or less work without too
976 * much confusion -- but then, stop work should not
977 * rely on PI working anyway.
979 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
981 stop
->sched_class
= &stop_sched_class
;
984 cpu_rq(cpu
)->stop
= stop
;
988 * Reset it back to a normal scheduling class so that
989 * it can die in pieces.
991 old_stop
->sched_class
= &rt_sched_class
;
996 * __normal_prio - return the priority that is based on the static prio
998 static inline int __normal_prio(struct task_struct
*p
)
1000 return p
->static_prio
;
1004 * Calculate the expected normal priority: i.e. priority
1005 * without taking RT-inheritance into account. Might be
1006 * boosted by interactivity modifiers. Changes upon fork,
1007 * setprio syscalls, and whenever the interactivity
1008 * estimator recalculates.
1010 static inline int normal_prio(struct task_struct
*p
)
1014 if (task_has_rt_policy(p
))
1015 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1017 prio
= __normal_prio(p
);
1022 * Calculate the current priority, i.e. the priority
1023 * taken into account by the scheduler. This value might
1024 * be boosted by RT tasks, or might be boosted by
1025 * interactivity modifiers. Will be RT if the task got
1026 * RT-boosted. If not then it returns p->normal_prio.
1028 static int effective_prio(struct task_struct
*p
)
1030 p
->normal_prio
= normal_prio(p
);
1032 * If we are RT tasks or we were boosted to RT priority,
1033 * keep the priority unchanged. Otherwise, update priority
1034 * to the normal priority:
1036 if (!rt_prio(p
->prio
))
1037 return p
->normal_prio
;
1042 * task_curr - is this task currently executing on a CPU?
1043 * @p: the task in question.
1045 inline int task_curr(const struct task_struct
*p
)
1047 return cpu_curr(task_cpu(p
)) == p
;
1050 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1051 const struct sched_class
*prev_class
,
1054 if (prev_class
!= p
->sched_class
) {
1055 if (prev_class
->switched_from
)
1056 prev_class
->switched_from(rq
, p
);
1057 p
->sched_class
->switched_to(rq
, p
);
1058 } else if (oldprio
!= p
->prio
)
1059 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
1062 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
1064 const struct sched_class
*class;
1066 if (p
->sched_class
== rq
->curr
->sched_class
) {
1067 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
1069 for_each_class(class) {
1070 if (class == rq
->curr
->sched_class
)
1072 if (class == p
->sched_class
) {
1073 resched_task(rq
->curr
);
1080 * A queue event has occurred, and we're going to schedule. In
1081 * this case, we can save a useless back to back clock update.
1083 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
1084 rq
->skip_clock_update
= 1;
1088 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1090 #ifdef CONFIG_SCHED_DEBUG
1092 * We should never call set_task_cpu() on a blocked task,
1093 * ttwu() will sort out the placement.
1095 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
1096 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
1098 #ifdef CONFIG_LOCKDEP
1100 * The caller should hold either p->pi_lock or rq->lock, when changing
1101 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1103 * sched_move_task() holds both and thus holding either pins the cgroup,
1104 * see set_task_rq().
1106 * Furthermore, all task_rq users should acquire both locks, see
1109 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1110 lockdep_is_held(&task_rq(p
)->lock
)));
1114 trace_sched_migrate_task(p
, new_cpu
);
1116 if (task_cpu(p
) != new_cpu
) {
1117 p
->se
.nr_migrations
++;
1118 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1121 __set_task_cpu(p
, new_cpu
);
1124 struct migration_arg
{
1125 struct task_struct
*task
;
1129 static int migration_cpu_stop(void *data
);
1132 * wait_task_inactive - wait for a thread to unschedule.
1134 * If @match_state is nonzero, it's the @p->state value just checked and
1135 * not expected to change. If it changes, i.e. @p might have woken up,
1136 * then return zero. When we succeed in waiting for @p to be off its CPU,
1137 * we return a positive number (its total switch count). If a second call
1138 * a short while later returns the same number, the caller can be sure that
1139 * @p has remained unscheduled the whole time.
1141 * The caller must ensure that the task *will* unschedule sometime soon,
1142 * else this function might spin for a *long* time. This function can't
1143 * be called with interrupts off, or it may introduce deadlock with
1144 * smp_call_function() if an IPI is sent by the same process we are
1145 * waiting to become inactive.
1147 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1149 unsigned long flags
;
1156 * We do the initial early heuristics without holding
1157 * any task-queue locks at all. We'll only try to get
1158 * the runqueue lock when things look like they will
1164 * If the task is actively running on another CPU
1165 * still, just relax and busy-wait without holding
1168 * NOTE! Since we don't hold any locks, it's not
1169 * even sure that "rq" stays as the right runqueue!
1170 * But we don't care, since "task_running()" will
1171 * return false if the runqueue has changed and p
1172 * is actually now running somewhere else!
1174 while (task_running(rq
, p
)) {
1175 if (match_state
&& unlikely(p
->state
!= match_state
))
1181 * Ok, time to look more closely! We need the rq
1182 * lock now, to be *sure*. If we're wrong, we'll
1183 * just go back and repeat.
1185 rq
= task_rq_lock(p
, &flags
);
1186 trace_sched_wait_task(p
);
1187 running
= task_running(rq
, p
);
1190 if (!match_state
|| p
->state
== match_state
)
1191 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1192 task_rq_unlock(rq
, p
, &flags
);
1195 * If it changed from the expected state, bail out now.
1197 if (unlikely(!ncsw
))
1201 * Was it really running after all now that we
1202 * checked with the proper locks actually held?
1204 * Oops. Go back and try again..
1206 if (unlikely(running
)) {
1212 * It's not enough that it's not actively running,
1213 * it must be off the runqueue _entirely_, and not
1216 * So if it was still runnable (but just not actively
1217 * running right now), it's preempted, and we should
1218 * yield - it could be a while.
1220 if (unlikely(on_rq
)) {
1221 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1223 set_current_state(TASK_UNINTERRUPTIBLE
);
1224 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1229 * Ahh, all good. It wasn't running, and it wasn't
1230 * runnable, which means that it will never become
1231 * running in the future either. We're all done!
1240 * kick_process - kick a running thread to enter/exit the kernel
1241 * @p: the to-be-kicked thread
1243 * Cause a process which is running on another CPU to enter
1244 * kernel-mode, without any delay. (to get signals handled.)
1246 * NOTE: this function doesn't have to take the runqueue lock,
1247 * because all it wants to ensure is that the remote task enters
1248 * the kernel. If the IPI races and the task has been migrated
1249 * to another CPU then no harm is done and the purpose has been
1252 void kick_process(struct task_struct
*p
)
1258 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1259 smp_send_reschedule(cpu
);
1262 EXPORT_SYMBOL_GPL(kick_process
);
1263 #endif /* CONFIG_SMP */
1267 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1269 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1272 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
1274 /* Look for allowed, online CPU in same node. */
1275 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
1276 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1279 /* Any allowed, online CPU? */
1280 dest_cpu
= cpumask_any_and(tsk_cpus_allowed(p
), cpu_active_mask
);
1281 if (dest_cpu
< nr_cpu_ids
)
1284 /* No more Mr. Nice Guy. */
1285 dest_cpu
= cpuset_cpus_allowed_fallback(p
);
1287 * Don't tell them about moving exiting tasks or
1288 * kernel threads (both mm NULL), since they never
1291 if (p
->mm
&& printk_ratelimit()) {
1292 printk(KERN_INFO
"process %d (%s) no longer affine to cpu%d\n",
1293 task_pid_nr(p
), p
->comm
, cpu
);
1300 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1303 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
1305 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
1308 * In order not to call set_task_cpu() on a blocking task we need
1309 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1312 * Since this is common to all placement strategies, this lives here.
1314 * [ this allows ->select_task() to simply return task_cpu(p) and
1315 * not worry about this generic constraint ]
1317 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1319 cpu
= select_fallback_rq(task_cpu(p
), p
);
1324 static void update_avg(u64
*avg
, u64 sample
)
1326 s64 diff
= sample
- *avg
;
1332 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1334 #ifdef CONFIG_SCHEDSTATS
1335 struct rq
*rq
= this_rq();
1338 int this_cpu
= smp_processor_id();
1340 if (cpu
== this_cpu
) {
1341 schedstat_inc(rq
, ttwu_local
);
1342 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1344 struct sched_domain
*sd
;
1346 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1348 for_each_domain(this_cpu
, sd
) {
1349 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1350 schedstat_inc(sd
, ttwu_wake_remote
);
1357 if (wake_flags
& WF_MIGRATED
)
1358 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1360 #endif /* CONFIG_SMP */
1362 schedstat_inc(rq
, ttwu_count
);
1363 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1365 if (wake_flags
& WF_SYNC
)
1366 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1368 #endif /* CONFIG_SCHEDSTATS */
1371 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1373 activate_task(rq
, p
, en_flags
);
1376 /* if a worker is waking up, notify workqueue */
1377 if (p
->flags
& PF_WQ_WORKER
)
1378 wq_worker_waking_up(p
, cpu_of(rq
));
1382 * Mark the task runnable and perform wakeup-preemption.
1385 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1387 trace_sched_wakeup(p
, true);
1388 check_preempt_curr(rq
, p
, wake_flags
);
1390 p
->state
= TASK_RUNNING
;
1392 if (p
->sched_class
->task_woken
)
1393 p
->sched_class
->task_woken(rq
, p
);
1395 if (rq
->idle_stamp
) {
1396 u64 delta
= rq
->clock
- rq
->idle_stamp
;
1397 u64 max
= 2*sysctl_sched_migration_cost
;
1402 update_avg(&rq
->avg_idle
, delta
);
1409 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1412 if (p
->sched_contributes_to_load
)
1413 rq
->nr_uninterruptible
--;
1416 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1417 ttwu_do_wakeup(rq
, p
, wake_flags
);
1421 * Called in case the task @p isn't fully descheduled from its runqueue,
1422 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1423 * since all we need to do is flip p->state to TASK_RUNNING, since
1424 * the task is still ->on_rq.
1426 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1431 rq
= __task_rq_lock(p
);
1433 ttwu_do_wakeup(rq
, p
, wake_flags
);
1436 __task_rq_unlock(rq
);
1442 static void sched_ttwu_pending(void)
1444 struct rq
*rq
= this_rq();
1445 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1446 struct task_struct
*p
;
1448 raw_spin_lock(&rq
->lock
);
1451 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1452 llist
= llist_next(llist
);
1453 ttwu_do_activate(rq
, p
, 0);
1456 raw_spin_unlock(&rq
->lock
);
1459 void scheduler_ipi(void)
1461 if (llist_empty(&this_rq()->wake_list
) && !got_nohz_idle_kick())
1465 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1466 * traditionally all their work was done from the interrupt return
1467 * path. Now that we actually do some work, we need to make sure
1470 * Some archs already do call them, luckily irq_enter/exit nest
1473 * Arguably we should visit all archs and update all handlers,
1474 * however a fair share of IPIs are still resched only so this would
1475 * somewhat pessimize the simple resched case.
1478 sched_ttwu_pending();
1481 * Check if someone kicked us for doing the nohz idle load balance.
1483 if (unlikely(got_nohz_idle_kick() && !need_resched())) {
1484 this_rq()->idle_balance
= 1;
1485 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1490 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1492 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
1493 smp_send_reschedule(cpu
);
1496 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1497 static int ttwu_activate_remote(struct task_struct
*p
, int wake_flags
)
1502 rq
= __task_rq_lock(p
);
1504 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1505 ttwu_do_wakeup(rq
, p
, wake_flags
);
1508 __task_rq_unlock(rq
);
1513 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1515 static inline int ttwu_share_cache(int this_cpu
, int that_cpu
)
1517 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1519 #endif /* CONFIG_SMP */
1521 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1523 struct rq
*rq
= cpu_rq(cpu
);
1525 #if defined(CONFIG_SMP)
1526 if (sched_feat(TTWU_QUEUE
) && !ttwu_share_cache(smp_processor_id(), cpu
)) {
1527 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1528 ttwu_queue_remote(p
, cpu
);
1533 raw_spin_lock(&rq
->lock
);
1534 ttwu_do_activate(rq
, p
, 0);
1535 raw_spin_unlock(&rq
->lock
);
1539 * try_to_wake_up - wake up a thread
1540 * @p: the thread to be awakened
1541 * @state: the mask of task states that can be woken
1542 * @wake_flags: wake modifier flags (WF_*)
1544 * Put it on the run-queue if it's not already there. The "current"
1545 * thread is always on the run-queue (except when the actual
1546 * re-schedule is in progress), and as such you're allowed to do
1547 * the simpler "current->state = TASK_RUNNING" to mark yourself
1548 * runnable without the overhead of this.
1550 * Returns %true if @p was woken up, %false if it was already running
1551 * or @state didn't match @p's state.
1554 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1556 unsigned long flags
;
1557 int cpu
, success
= 0;
1560 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1561 if (!(p
->state
& state
))
1564 success
= 1; /* we're going to change ->state */
1567 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1572 * If the owning (remote) cpu is still in the middle of schedule() with
1573 * this task as prev, wait until its done referencing the task.
1576 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1578 * In case the architecture enables interrupts in
1579 * context_switch(), we cannot busy wait, since that
1580 * would lead to deadlocks when an interrupt hits and
1581 * tries to wake up @prev. So bail and do a complete
1584 if (ttwu_activate_remote(p
, wake_flags
))
1591 * Pairs with the smp_wmb() in finish_lock_switch().
1595 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1596 p
->state
= TASK_WAKING
;
1598 if (p
->sched_class
->task_waking
)
1599 p
->sched_class
->task_waking(p
);
1601 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
1602 if (task_cpu(p
) != cpu
) {
1603 wake_flags
|= WF_MIGRATED
;
1604 set_task_cpu(p
, cpu
);
1606 #endif /* CONFIG_SMP */
1610 ttwu_stat(p
, cpu
, wake_flags
);
1612 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1618 * try_to_wake_up_local - try to wake up a local task with rq lock held
1619 * @p: the thread to be awakened
1621 * Put @p on the run-queue if it's not already there. The caller must
1622 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1625 static void try_to_wake_up_local(struct task_struct
*p
)
1627 struct rq
*rq
= task_rq(p
);
1629 BUG_ON(rq
!= this_rq());
1630 BUG_ON(p
== current
);
1631 lockdep_assert_held(&rq
->lock
);
1633 if (!raw_spin_trylock(&p
->pi_lock
)) {
1634 raw_spin_unlock(&rq
->lock
);
1635 raw_spin_lock(&p
->pi_lock
);
1636 raw_spin_lock(&rq
->lock
);
1639 if (!(p
->state
& TASK_NORMAL
))
1643 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1645 ttwu_do_wakeup(rq
, p
, 0);
1646 ttwu_stat(p
, smp_processor_id(), 0);
1648 raw_spin_unlock(&p
->pi_lock
);
1652 * wake_up_process - Wake up a specific process
1653 * @p: The process to be woken up.
1655 * Attempt to wake up the nominated process and move it to the set of runnable
1656 * processes. Returns 1 if the process was woken up, 0 if it was already
1659 * It may be assumed that this function implies a write memory barrier before
1660 * changing the task state if and only if any tasks are woken up.
1662 int wake_up_process(struct task_struct
*p
)
1664 return try_to_wake_up(p
, TASK_ALL
, 0);
1666 EXPORT_SYMBOL(wake_up_process
);
1668 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1670 return try_to_wake_up(p
, state
, 0);
1674 * Perform scheduler related setup for a newly forked process p.
1675 * p is forked by current.
1677 * __sched_fork() is basic setup used by init_idle() too:
1679 static void __sched_fork(struct task_struct
*p
)
1684 p
->se
.exec_start
= 0;
1685 p
->se
.sum_exec_runtime
= 0;
1686 p
->se
.prev_sum_exec_runtime
= 0;
1687 p
->se
.nr_migrations
= 0;
1689 INIT_LIST_HEAD(&p
->se
.group_node
);
1691 #ifdef CONFIG_SCHEDSTATS
1692 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1695 INIT_LIST_HEAD(&p
->rt
.run_list
);
1697 #ifdef CONFIG_PREEMPT_NOTIFIERS
1698 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1703 * fork()/clone()-time setup:
1705 void sched_fork(struct task_struct
*p
)
1707 unsigned long flags
;
1708 int cpu
= get_cpu();
1712 * We mark the process as running here. This guarantees that
1713 * nobody will actually run it, and a signal or other external
1714 * event cannot wake it up and insert it on the runqueue either.
1716 p
->state
= TASK_RUNNING
;
1719 * Make sure we do not leak PI boosting priority to the child.
1721 p
->prio
= current
->normal_prio
;
1724 * Revert to default priority/policy on fork if requested.
1726 if (unlikely(p
->sched_reset_on_fork
)) {
1727 if (task_has_rt_policy(p
)) {
1728 p
->policy
= SCHED_NORMAL
;
1729 p
->static_prio
= NICE_TO_PRIO(0);
1731 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1732 p
->static_prio
= NICE_TO_PRIO(0);
1734 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1738 * We don't need the reset flag anymore after the fork. It has
1739 * fulfilled its duty:
1741 p
->sched_reset_on_fork
= 0;
1744 if (!rt_prio(p
->prio
))
1745 p
->sched_class
= &fair_sched_class
;
1747 if (p
->sched_class
->task_fork
)
1748 p
->sched_class
->task_fork(p
);
1751 * The child is not yet in the pid-hash so no cgroup attach races,
1752 * and the cgroup is pinned to this child due to cgroup_fork()
1753 * is ran before sched_fork().
1755 * Silence PROVE_RCU.
1757 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1758 set_task_cpu(p
, cpu
);
1759 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1761 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1762 if (likely(sched_info_on()))
1763 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1765 #if defined(CONFIG_SMP)
1768 #ifdef CONFIG_PREEMPT_COUNT
1769 /* Want to start with kernel preemption disabled. */
1770 task_thread_info(p
)->preempt_count
= 1;
1773 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1780 * wake_up_new_task - wake up a newly created task for the first time.
1782 * This function will do some initial scheduler statistics housekeeping
1783 * that must be done for every newly created context, then puts the task
1784 * on the runqueue and wakes it.
1786 void wake_up_new_task(struct task_struct
*p
)
1788 unsigned long flags
;
1791 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1794 * Fork balancing, do it here and not earlier because:
1795 * - cpus_allowed can change in the fork path
1796 * - any previously selected cpu might disappear through hotplug
1798 set_task_cpu(p
, select_task_rq(p
, SD_BALANCE_FORK
, 0));
1801 rq
= __task_rq_lock(p
);
1802 activate_task(rq
, p
, 0);
1804 trace_sched_wakeup_new(p
, true);
1805 check_preempt_curr(rq
, p
, WF_FORK
);
1807 if (p
->sched_class
->task_woken
)
1808 p
->sched_class
->task_woken(rq
, p
);
1810 task_rq_unlock(rq
, p
, &flags
);
1813 #ifdef CONFIG_PREEMPT_NOTIFIERS
1816 * preempt_notifier_register - tell me when current is being preempted & rescheduled
1817 * @notifier: notifier struct to register
1819 void preempt_notifier_register(struct preempt_notifier
*notifier
)
1821 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
1823 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
1826 * preempt_notifier_unregister - no longer interested in preemption notifications
1827 * @notifier: notifier struct to unregister
1829 * This is safe to call from within a preemption notifier.
1831 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
1833 hlist_del(¬ifier
->link
);
1835 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
1837 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1839 struct preempt_notifier
*notifier
;
1840 struct hlist_node
*node
;
1842 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
1843 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
1847 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1848 struct task_struct
*next
)
1850 struct preempt_notifier
*notifier
;
1851 struct hlist_node
*node
;
1853 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
1854 notifier
->ops
->sched_out(notifier
, next
);
1857 #else /* !CONFIG_PREEMPT_NOTIFIERS */
1859 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
1864 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
1865 struct task_struct
*next
)
1869 #endif /* CONFIG_PREEMPT_NOTIFIERS */
1872 * prepare_task_switch - prepare to switch tasks
1873 * @rq: the runqueue preparing to switch
1874 * @prev: the current task that is being switched out
1875 * @next: the task we are going to switch to.
1877 * This is called with the rq lock held and interrupts off. It must
1878 * be paired with a subsequent finish_task_switch after the context
1881 * prepare_task_switch sets up locking and calls architecture specific
1885 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
1886 struct task_struct
*next
)
1888 sched_info_switch(prev
, next
);
1889 perf_event_task_sched_out(prev
, next
);
1890 fire_sched_out_preempt_notifiers(prev
, next
);
1891 prepare_lock_switch(rq
, next
);
1892 prepare_arch_switch(next
);
1893 trace_sched_switch(prev
, next
);
1897 * finish_task_switch - clean up after a task-switch
1898 * @rq: runqueue associated with task-switch
1899 * @prev: the thread we just switched away from.
1901 * finish_task_switch must be called after the context switch, paired
1902 * with a prepare_task_switch call before the context switch.
1903 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1904 * and do any other architecture-specific cleanup actions.
1906 * Note that we may have delayed dropping an mm in context_switch(). If
1907 * so, we finish that here outside of the runqueue lock. (Doing it
1908 * with the lock held can cause deadlocks; see schedule() for
1911 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
1912 __releases(rq
->lock
)
1914 struct mm_struct
*mm
= rq
->prev_mm
;
1920 * A task struct has one reference for the use as "current".
1921 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
1922 * schedule one last time. The schedule call will never return, and
1923 * the scheduled task must drop that reference.
1924 * The test for TASK_DEAD must occur while the runqueue locks are
1925 * still held, otherwise prev could be scheduled on another cpu, die
1926 * there before we look at prev->state, and then the reference would
1928 * Manfred Spraul <manfred@colorfullife.com>
1930 prev_state
= prev
->state
;
1931 finish_arch_switch(prev
);
1932 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1933 local_irq_disable();
1934 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1935 perf_event_task_sched_in(prev
, current
);
1936 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1938 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
1939 finish_lock_switch(rq
, prev
);
1940 trace_sched_stat_sleeptime(current
, rq
->clock
);
1942 fire_sched_in_preempt_notifiers(current
);
1945 if (unlikely(prev_state
== TASK_DEAD
)) {
1947 * Remove function-return probe instances associated with this
1948 * task and put them back on the free list.
1950 kprobe_flush_task(prev
);
1951 put_task_struct(prev
);
1957 /* assumes rq->lock is held */
1958 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
1960 if (prev
->sched_class
->pre_schedule
)
1961 prev
->sched_class
->pre_schedule(rq
, prev
);
1964 /* rq->lock is NOT held, but preemption is disabled */
1965 static inline void post_schedule(struct rq
*rq
)
1967 if (rq
->post_schedule
) {
1968 unsigned long flags
;
1970 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1971 if (rq
->curr
->sched_class
->post_schedule
)
1972 rq
->curr
->sched_class
->post_schedule(rq
);
1973 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1975 rq
->post_schedule
= 0;
1981 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
1985 static inline void post_schedule(struct rq
*rq
)
1992 * schedule_tail - first thing a freshly forked thread must call.
1993 * @prev: the thread we just switched away from.
1995 asmlinkage
void schedule_tail(struct task_struct
*prev
)
1996 __releases(rq
->lock
)
1998 struct rq
*rq
= this_rq();
2000 finish_task_switch(rq
, prev
);
2003 * FIXME: do we need to worry about rq being invalidated by the
2008 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2009 /* In this case, finish_task_switch does not reenable preemption */
2012 if (current
->set_child_tid
)
2013 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2017 * context_switch - switch to the new MM and the new
2018 * thread's register state.
2021 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2022 struct task_struct
*next
)
2024 struct mm_struct
*mm
, *oldmm
;
2026 prepare_task_switch(rq
, prev
, next
);
2029 oldmm
= prev
->active_mm
;
2031 * For paravirt, this is coupled with an exit in switch_to to
2032 * combine the page table reload and the switch backend into
2035 arch_start_context_switch(prev
);
2038 next
->active_mm
= oldmm
;
2039 atomic_inc(&oldmm
->mm_count
);
2040 enter_lazy_tlb(oldmm
, next
);
2042 switch_mm(oldmm
, mm
, next
);
2045 prev
->active_mm
= NULL
;
2046 rq
->prev_mm
= oldmm
;
2049 * Since the runqueue lock will be released by the next
2050 * task (which is an invalid locking op but in the case
2051 * of the scheduler it's an obvious special-case), so we
2052 * do an early lockdep release here:
2054 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2055 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2058 /* Here we just switch the register state and the stack. */
2059 switch_to(prev
, next
, prev
);
2063 * this_rq must be evaluated again because prev may have moved
2064 * CPUs since it called schedule(), thus the 'rq' on its stack
2065 * frame will be invalid.
2067 finish_task_switch(this_rq(), prev
);
2071 * nr_running, nr_uninterruptible and nr_context_switches:
2073 * externally visible scheduler statistics: current number of runnable
2074 * threads, current number of uninterruptible-sleeping threads, total
2075 * number of context switches performed since bootup.
2077 unsigned long nr_running(void)
2079 unsigned long i
, sum
= 0;
2081 for_each_online_cpu(i
)
2082 sum
+= cpu_rq(i
)->nr_running
;
2087 unsigned long nr_uninterruptible(void)
2089 unsigned long i
, sum
= 0;
2091 for_each_possible_cpu(i
)
2092 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2095 * Since we read the counters lockless, it might be slightly
2096 * inaccurate. Do not allow it to go below zero though:
2098 if (unlikely((long)sum
< 0))
2104 unsigned long long nr_context_switches(void)
2107 unsigned long long sum
= 0;
2109 for_each_possible_cpu(i
)
2110 sum
+= cpu_rq(i
)->nr_switches
;
2115 unsigned long nr_iowait(void)
2117 unsigned long i
, sum
= 0;
2119 for_each_possible_cpu(i
)
2120 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2125 unsigned long nr_iowait_cpu(int cpu
)
2127 struct rq
*this = cpu_rq(cpu
);
2128 return atomic_read(&this->nr_iowait
);
2131 unsigned long this_cpu_load(void)
2133 struct rq
*this = this_rq();
2134 return this->cpu_load
[0];
2138 /* Variables and functions for calc_load */
2139 static atomic_long_t calc_load_tasks
;
2140 static unsigned long calc_load_update
;
2141 unsigned long avenrun
[3];
2142 EXPORT_SYMBOL(avenrun
);
2144 static long calc_load_fold_active(struct rq
*this_rq
)
2146 long nr_active
, delta
= 0;
2148 nr_active
= this_rq
->nr_running
;
2149 nr_active
+= (long) this_rq
->nr_uninterruptible
;
2151 if (nr_active
!= this_rq
->calc_load_active
) {
2152 delta
= nr_active
- this_rq
->calc_load_active
;
2153 this_rq
->calc_load_active
= nr_active
;
2159 static unsigned long
2160 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
2163 load
+= active
* (FIXED_1
- exp
);
2164 load
+= 1UL << (FSHIFT
- 1);
2165 return load
>> FSHIFT
;
2170 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
2172 * When making the ILB scale, we should try to pull this in as well.
2174 static atomic_long_t calc_load_tasks_idle
;
2176 void calc_load_account_idle(struct rq
*this_rq
)
2180 delta
= calc_load_fold_active(this_rq
);
2182 atomic_long_add(delta
, &calc_load_tasks_idle
);
2185 static long calc_load_fold_idle(void)
2190 * Its got a race, we don't care...
2192 if (atomic_long_read(&calc_load_tasks_idle
))
2193 delta
= atomic_long_xchg(&calc_load_tasks_idle
, 0);
2199 * fixed_power_int - compute: x^n, in O(log n) time
2201 * @x: base of the power
2202 * @frac_bits: fractional bits of @x
2203 * @n: power to raise @x to.
2205 * By exploiting the relation between the definition of the natural power
2206 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
2207 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
2208 * (where: n_i \elem {0, 1}, the binary vector representing n),
2209 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
2210 * of course trivially computable in O(log_2 n), the length of our binary
2213 static unsigned long
2214 fixed_power_int(unsigned long x
, unsigned int frac_bits
, unsigned int n
)
2216 unsigned long result
= 1UL << frac_bits
;
2221 result
+= 1UL << (frac_bits
- 1);
2222 result
>>= frac_bits
;
2228 x
+= 1UL << (frac_bits
- 1);
2236 * a1 = a0 * e + a * (1 - e)
2238 * a2 = a1 * e + a * (1 - e)
2239 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
2240 * = a0 * e^2 + a * (1 - e) * (1 + e)
2242 * a3 = a2 * e + a * (1 - e)
2243 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
2244 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
2248 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
2249 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
2250 * = a0 * e^n + a * (1 - e^n)
2252 * [1] application of the geometric series:
2255 * S_n := \Sum x^i = -------------
2258 static unsigned long
2259 calc_load_n(unsigned long load
, unsigned long exp
,
2260 unsigned long active
, unsigned int n
)
2263 return calc_load(load
, fixed_power_int(exp
, FSHIFT
, n
), active
);
2267 * NO_HZ can leave us missing all per-cpu ticks calling
2268 * calc_load_account_active(), but since an idle CPU folds its delta into
2269 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
2270 * in the pending idle delta if our idle period crossed a load cycle boundary.
2272 * Once we've updated the global active value, we need to apply the exponential
2273 * weights adjusted to the number of cycles missed.
2275 static void calc_global_nohz(unsigned long ticks
)
2277 long delta
, active
, n
;
2279 if (time_before(jiffies
, calc_load_update
))
2283 * If we crossed a calc_load_update boundary, make sure to fold
2284 * any pending idle changes, the respective CPUs might have
2285 * missed the tick driven calc_load_account_active() update
2288 delta
= calc_load_fold_idle();
2290 atomic_long_add(delta
, &calc_load_tasks
);
2293 * If we were idle for multiple load cycles, apply them.
2295 if (ticks
>= LOAD_FREQ
) {
2296 n
= ticks
/ LOAD_FREQ
;
2298 active
= atomic_long_read(&calc_load_tasks
);
2299 active
= active
> 0 ? active
* FIXED_1
: 0;
2301 avenrun
[0] = calc_load_n(avenrun
[0], EXP_1
, active
, n
);
2302 avenrun
[1] = calc_load_n(avenrun
[1], EXP_5
, active
, n
);
2303 avenrun
[2] = calc_load_n(avenrun
[2], EXP_15
, active
, n
);
2305 calc_load_update
+= n
* LOAD_FREQ
;
2309 * Its possible the remainder of the above division also crosses
2310 * a LOAD_FREQ period, the regular check in calc_global_load()
2311 * which comes after this will take care of that.
2313 * Consider us being 11 ticks before a cycle completion, and us
2314 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
2315 * age us 4 cycles, and the test in calc_global_load() will
2316 * pick up the final one.
2320 void calc_load_account_idle(struct rq
*this_rq
)
2324 static inline long calc_load_fold_idle(void)
2329 static void calc_global_nohz(unsigned long ticks
)
2335 * get_avenrun - get the load average array
2336 * @loads: pointer to dest load array
2337 * @offset: offset to add
2338 * @shift: shift count to shift the result left
2340 * These values are estimates at best, so no need for locking.
2342 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
2344 loads
[0] = (avenrun
[0] + offset
) << shift
;
2345 loads
[1] = (avenrun
[1] + offset
) << shift
;
2346 loads
[2] = (avenrun
[2] + offset
) << shift
;
2350 * calc_load - update the avenrun load estimates 10 ticks after the
2351 * CPUs have updated calc_load_tasks.
2353 void calc_global_load(unsigned long ticks
)
2357 calc_global_nohz(ticks
);
2359 if (time_before(jiffies
, calc_load_update
+ 10))
2362 active
= atomic_long_read(&calc_load_tasks
);
2363 active
= active
> 0 ? active
* FIXED_1
: 0;
2365 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
2366 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
2367 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
2369 calc_load_update
+= LOAD_FREQ
;
2373 * Called from update_cpu_load() to periodically update this CPU's
2376 static void calc_load_account_active(struct rq
*this_rq
)
2380 if (time_before(jiffies
, this_rq
->calc_load_update
))
2383 delta
= calc_load_fold_active(this_rq
);
2384 delta
+= calc_load_fold_idle();
2386 atomic_long_add(delta
, &calc_load_tasks
);
2388 this_rq
->calc_load_update
+= LOAD_FREQ
;
2392 * The exact cpuload at various idx values, calculated at every tick would be
2393 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
2395 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
2396 * on nth tick when cpu may be busy, then we have:
2397 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2398 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
2400 * decay_load_missed() below does efficient calculation of
2401 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
2402 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
2404 * The calculation is approximated on a 128 point scale.
2405 * degrade_zero_ticks is the number of ticks after which load at any
2406 * particular idx is approximated to be zero.
2407 * degrade_factor is a precomputed table, a row for each load idx.
2408 * Each column corresponds to degradation factor for a power of two ticks,
2409 * based on 128 point scale.
2411 * row 2, col 3 (=12) says that the degradation at load idx 2 after
2412 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
2414 * With this power of 2 load factors, we can degrade the load n times
2415 * by looking at 1 bits in n and doing as many mult/shift instead of
2416 * n mult/shifts needed by the exact degradation.
2418 #define DEGRADE_SHIFT 7
2419 static const unsigned char
2420 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
2421 static const unsigned char
2422 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
2423 {0, 0, 0, 0, 0, 0, 0, 0},
2424 {64, 32, 8, 0, 0, 0, 0, 0},
2425 {96, 72, 40, 12, 1, 0, 0},
2426 {112, 98, 75, 43, 15, 1, 0},
2427 {120, 112, 98, 76, 45, 16, 2} };
2430 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
2431 * would be when CPU is idle and so we just decay the old load without
2432 * adding any new load.
2434 static unsigned long
2435 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
2439 if (!missed_updates
)
2442 if (missed_updates
>= degrade_zero_ticks
[idx
])
2446 return load
>> missed_updates
;
2448 while (missed_updates
) {
2449 if (missed_updates
% 2)
2450 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
2452 missed_updates
>>= 1;
2459 * Update rq->cpu_load[] statistics. This function is usually called every
2460 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
2461 * every tick. We fix it up based on jiffies.
2463 void update_cpu_load(struct rq
*this_rq
)
2465 unsigned long this_load
= this_rq
->load
.weight
;
2466 unsigned long curr_jiffies
= jiffies
;
2467 unsigned long pending_updates
;
2470 this_rq
->nr_load_updates
++;
2472 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
2473 if (curr_jiffies
== this_rq
->last_load_update_tick
)
2476 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
2477 this_rq
->last_load_update_tick
= curr_jiffies
;
2479 /* Update our load: */
2480 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
2481 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2482 unsigned long old_load
, new_load
;
2484 /* scale is effectively 1 << i now, and >> i divides by scale */
2486 old_load
= this_rq
->cpu_load
[i
];
2487 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
2488 new_load
= this_load
;
2490 * Round up the averaging division if load is increasing. This
2491 * prevents us from getting stuck on 9 if the load is 10, for
2494 if (new_load
> old_load
)
2495 new_load
+= scale
- 1;
2497 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
2500 sched_avg_update(this_rq
);
2503 static void update_cpu_load_active(struct rq
*this_rq
)
2505 update_cpu_load(this_rq
);
2507 calc_load_account_active(this_rq
);
2513 * sched_exec - execve() is a valuable balancing opportunity, because at
2514 * this point the task has the smallest effective memory and cache footprint.
2516 void sched_exec(void)
2518 struct task_struct
*p
= current
;
2519 unsigned long flags
;
2522 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2523 dest_cpu
= p
->sched_class
->select_task_rq(p
, SD_BALANCE_EXEC
, 0);
2524 if (dest_cpu
== smp_processor_id())
2527 if (likely(cpu_active(dest_cpu
))) {
2528 struct migration_arg arg
= { p
, dest_cpu
};
2530 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2531 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2535 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2540 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2541 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2543 EXPORT_PER_CPU_SYMBOL(kstat
);
2544 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2547 * Return any ns on the sched_clock that have not yet been accounted in
2548 * @p in case that task is currently running.
2550 * Called with task_rq_lock() held on @rq.
2552 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2556 if (task_current(rq
, p
)) {
2557 update_rq_clock(rq
);
2558 ns
= rq
->clock_task
- p
->se
.exec_start
;
2566 unsigned long long task_delta_exec(struct task_struct
*p
)
2568 unsigned long flags
;
2572 rq
= task_rq_lock(p
, &flags
);
2573 ns
= do_task_delta_exec(p
, rq
);
2574 task_rq_unlock(rq
, p
, &flags
);
2580 * Return accounted runtime for the task.
2581 * In case the task is currently running, return the runtime plus current's
2582 * pending runtime that have not been accounted yet.
2584 unsigned long long task_sched_runtime(struct task_struct
*p
)
2586 unsigned long flags
;
2590 rq
= task_rq_lock(p
, &flags
);
2591 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2592 task_rq_unlock(rq
, p
, &flags
);
2597 #ifdef CONFIG_CGROUP_CPUACCT
2598 struct cgroup_subsys cpuacct_subsys
;
2599 struct cpuacct root_cpuacct
;
2602 static inline void task_group_account_field(struct task_struct
*p
, int index
,
2605 #ifdef CONFIG_CGROUP_CPUACCT
2606 struct kernel_cpustat
*kcpustat
;
2610 * Since all updates are sure to touch the root cgroup, we
2611 * get ourselves ahead and touch it first. If the root cgroup
2612 * is the only cgroup, then nothing else should be necessary.
2615 __get_cpu_var(kernel_cpustat
).cpustat
[index
] += tmp
;
2617 #ifdef CONFIG_CGROUP_CPUACCT
2618 if (unlikely(!cpuacct_subsys
.active
))
2623 while (ca
&& (ca
!= &root_cpuacct
)) {
2624 kcpustat
= this_cpu_ptr(ca
->cpustat
);
2625 kcpustat
->cpustat
[index
] += tmp
;
2634 * Account user cpu time to a process.
2635 * @p: the process that the cpu time gets accounted to
2636 * @cputime: the cpu time spent in user space since the last update
2637 * @cputime_scaled: cputime scaled by cpu frequency
2639 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
2640 cputime_t cputime_scaled
)
2644 /* Add user time to process. */
2645 p
->utime
+= cputime
;
2646 p
->utimescaled
+= cputime_scaled
;
2647 account_group_user_time(p
, cputime
);
2649 index
= (TASK_NICE(p
) > 0) ? CPUTIME_NICE
: CPUTIME_USER
;
2651 /* Add user time to cpustat. */
2652 task_group_account_field(p
, index
, (__force u64
) cputime
);
2654 /* Account for user time used */
2655 acct_update_integrals(p
);
2659 * Account guest cpu time to a process.
2660 * @p: the process that the cpu time gets accounted to
2661 * @cputime: the cpu time spent in virtual machine since the last update
2662 * @cputime_scaled: cputime scaled by cpu frequency
2664 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
2665 cputime_t cputime_scaled
)
2667 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
2669 /* Add guest time to process. */
2670 p
->utime
+= cputime
;
2671 p
->utimescaled
+= cputime_scaled
;
2672 account_group_user_time(p
, cputime
);
2673 p
->gtime
+= cputime
;
2675 /* Add guest time to cpustat. */
2676 if (TASK_NICE(p
) > 0) {
2677 cpustat
[CPUTIME_NICE
] += (__force u64
) cputime
;
2678 cpustat
[CPUTIME_GUEST_NICE
] += (__force u64
) cputime
;
2680 cpustat
[CPUTIME_USER
] += (__force u64
) cputime
;
2681 cpustat
[CPUTIME_GUEST
] += (__force u64
) cputime
;
2686 * Account system cpu time to a process and desired cpustat field
2687 * @p: the process that the cpu time gets accounted to
2688 * @cputime: the cpu time spent in kernel space since the last update
2689 * @cputime_scaled: cputime scaled by cpu frequency
2690 * @target_cputime64: pointer to cpustat field that has to be updated
2693 void __account_system_time(struct task_struct
*p
, cputime_t cputime
,
2694 cputime_t cputime_scaled
, int index
)
2696 /* Add system time to process. */
2697 p
->stime
+= cputime
;
2698 p
->stimescaled
+= cputime_scaled
;
2699 account_group_system_time(p
, cputime
);
2701 /* Add system time to cpustat. */
2702 task_group_account_field(p
, index
, (__force u64
) cputime
);
2704 /* Account for system time used */
2705 acct_update_integrals(p
);
2709 * Account system cpu time to a process.
2710 * @p: the process that the cpu time gets accounted to
2711 * @hardirq_offset: the offset to subtract from hardirq_count()
2712 * @cputime: the cpu time spent in kernel space since the last update
2713 * @cputime_scaled: cputime scaled by cpu frequency
2715 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
2716 cputime_t cputime
, cputime_t cputime_scaled
)
2720 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
2721 account_guest_time(p
, cputime
, cputime_scaled
);
2725 if (hardirq_count() - hardirq_offset
)
2726 index
= CPUTIME_IRQ
;
2727 else if (in_serving_softirq())
2728 index
= CPUTIME_SOFTIRQ
;
2730 index
= CPUTIME_SYSTEM
;
2732 __account_system_time(p
, cputime
, cputime_scaled
, index
);
2736 * Account for involuntary wait time.
2737 * @cputime: the cpu time spent in involuntary wait
2739 void account_steal_time(cputime_t cputime
)
2741 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
2743 cpustat
[CPUTIME_STEAL
] += (__force u64
) cputime
;
2747 * Account for idle time.
2748 * @cputime: the cpu time spent in idle wait
2750 void account_idle_time(cputime_t cputime
)
2752 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
2753 struct rq
*rq
= this_rq();
2755 if (atomic_read(&rq
->nr_iowait
) > 0)
2756 cpustat
[CPUTIME_IOWAIT
] += (__force u64
) cputime
;
2758 cpustat
[CPUTIME_IDLE
] += (__force u64
) cputime
;
2761 static __always_inline
bool steal_account_process_tick(void)
2763 #ifdef CONFIG_PARAVIRT
2764 if (static_branch(¶virt_steal_enabled
)) {
2767 steal
= paravirt_steal_clock(smp_processor_id());
2768 steal
-= this_rq()->prev_steal_time
;
2770 st
= steal_ticks(steal
);
2771 this_rq()->prev_steal_time
+= st
* TICK_NSEC
;
2773 account_steal_time(st
);
2780 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
2782 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
2784 * Account a tick to a process and cpustat
2785 * @p: the process that the cpu time gets accounted to
2786 * @user_tick: is the tick from userspace
2787 * @rq: the pointer to rq
2789 * Tick demultiplexing follows the order
2790 * - pending hardirq update
2791 * - pending softirq update
2795 * - check for guest_time
2796 * - else account as system_time
2798 * Check for hardirq is done both for system and user time as there is
2799 * no timer going off while we are on hardirq and hence we may never get an
2800 * opportunity to update it solely in system time.
2801 * p->stime and friends are only updated on system time and not on irq
2802 * softirq as those do not count in task exec_runtime any more.
2804 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
2807 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
2808 u64
*cpustat
= kcpustat_this_cpu
->cpustat
;
2810 if (steal_account_process_tick())
2813 if (irqtime_account_hi_update()) {
2814 cpustat
[CPUTIME_IRQ
] += (__force u64
) cputime_one_jiffy
;
2815 } else if (irqtime_account_si_update()) {
2816 cpustat
[CPUTIME_SOFTIRQ
] += (__force u64
) cputime_one_jiffy
;
2817 } else if (this_cpu_ksoftirqd() == p
) {
2819 * ksoftirqd time do not get accounted in cpu_softirq_time.
2820 * So, we have to handle it separately here.
2821 * Also, p->stime needs to be updated for ksoftirqd.
2823 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
2825 } else if (user_tick
) {
2826 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
2827 } else if (p
== rq
->idle
) {
2828 account_idle_time(cputime_one_jiffy
);
2829 } else if (p
->flags
& PF_VCPU
) { /* System time or guest time */
2830 account_guest_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
2832 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
2837 static void irqtime_account_idle_ticks(int ticks
)
2840 struct rq
*rq
= this_rq();
2842 for (i
= 0; i
< ticks
; i
++)
2843 irqtime_account_process_tick(current
, 0, rq
);
2845 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
2846 static void irqtime_account_idle_ticks(int ticks
) {}
2847 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
2849 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
2852 * Account a single tick of cpu time.
2853 * @p: the process that the cpu time gets accounted to
2854 * @user_tick: indicates if the tick is a user or a system tick
2856 void account_process_tick(struct task_struct
*p
, int user_tick
)
2858 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
2859 struct rq
*rq
= this_rq();
2861 if (sched_clock_irqtime
) {
2862 irqtime_account_process_tick(p
, user_tick
, rq
);
2866 if (steal_account_process_tick())
2870 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
2871 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
2872 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
2875 account_idle_time(cputime_one_jiffy
);
2879 * Account multiple ticks of steal time.
2880 * @p: the process from which the cpu time has been stolen
2881 * @ticks: number of stolen ticks
2883 void account_steal_ticks(unsigned long ticks
)
2885 account_steal_time(jiffies_to_cputime(ticks
));
2889 * Account multiple ticks of idle time.
2890 * @ticks: number of stolen ticks
2892 void account_idle_ticks(unsigned long ticks
)
2895 if (sched_clock_irqtime
) {
2896 irqtime_account_idle_ticks(ticks
);
2900 account_idle_time(jiffies_to_cputime(ticks
));
2906 * Use precise platform statistics if available:
2908 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
2909 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
2915 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
2917 struct task_cputime cputime
;
2919 thread_group_cputime(p
, &cputime
);
2921 *ut
= cputime
.utime
;
2922 *st
= cputime
.stime
;
2926 #ifndef nsecs_to_cputime
2927 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
2930 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
2932 cputime_t rtime
, utime
= p
->utime
, total
= utime
+ p
->stime
;
2935 * Use CFS's precise accounting:
2937 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
2940 u64 temp
= (__force u64
) rtime
;
2942 temp
*= (__force u64
) utime
;
2943 do_div(temp
, (__force u32
) total
);
2944 utime
= (__force cputime_t
) temp
;
2949 * Compare with previous values, to keep monotonicity:
2951 p
->prev_utime
= max(p
->prev_utime
, utime
);
2952 p
->prev_stime
= max(p
->prev_stime
, rtime
- p
->prev_utime
);
2954 *ut
= p
->prev_utime
;
2955 *st
= p
->prev_stime
;
2959 * Must be called with siglock held.
2961 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
2963 struct signal_struct
*sig
= p
->signal
;
2964 struct task_cputime cputime
;
2965 cputime_t rtime
, utime
, total
;
2967 thread_group_cputime(p
, &cputime
);
2969 total
= cputime
.utime
+ cputime
.stime
;
2970 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
2973 u64 temp
= (__force u64
) rtime
;
2975 temp
*= (__force u64
) cputime
.utime
;
2976 do_div(temp
, (__force u32
) total
);
2977 utime
= (__force cputime_t
) temp
;
2981 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
2982 sig
->prev_stime
= max(sig
->prev_stime
, rtime
- sig
->prev_utime
);
2984 *ut
= sig
->prev_utime
;
2985 *st
= sig
->prev_stime
;
2990 * This function gets called by the timer code, with HZ frequency.
2991 * We call it with interrupts disabled.
2993 void scheduler_tick(void)
2995 int cpu
= smp_processor_id();
2996 struct rq
*rq
= cpu_rq(cpu
);
2997 struct task_struct
*curr
= rq
->curr
;
3001 raw_spin_lock(&rq
->lock
);
3002 update_rq_clock(rq
);
3003 update_cpu_load_active(rq
);
3004 curr
->sched_class
->task_tick(rq
, curr
, 0);
3005 raw_spin_unlock(&rq
->lock
);
3007 perf_event_task_tick();
3010 rq
->idle_balance
= idle_cpu(cpu
);
3011 trigger_load_balance(rq
, cpu
);
3015 notrace
unsigned long get_parent_ip(unsigned long addr
)
3017 if (in_lock_functions(addr
)) {
3018 addr
= CALLER_ADDR2
;
3019 if (in_lock_functions(addr
))
3020 addr
= CALLER_ADDR3
;
3025 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3026 defined(CONFIG_PREEMPT_TRACER))
3028 void __kprobes
add_preempt_count(int val
)
3030 #ifdef CONFIG_DEBUG_PREEMPT
3034 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3037 preempt_count() += val
;
3038 #ifdef CONFIG_DEBUG_PREEMPT
3040 * Spinlock count overflowing soon?
3042 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3045 if (preempt_count() == val
)
3046 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3048 EXPORT_SYMBOL(add_preempt_count
);
3050 void __kprobes
sub_preempt_count(int val
)
3052 #ifdef CONFIG_DEBUG_PREEMPT
3056 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3059 * Is the spinlock portion underflowing?
3061 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3062 !(preempt_count() & PREEMPT_MASK
)))
3066 if (preempt_count() == val
)
3067 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3068 preempt_count() -= val
;
3070 EXPORT_SYMBOL(sub_preempt_count
);
3075 * Print scheduling while atomic bug:
3077 static noinline
void __schedule_bug(struct task_struct
*prev
)
3079 struct pt_regs
*regs
= get_irq_regs();
3081 if (oops_in_progress
)
3084 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3085 prev
->comm
, prev
->pid
, preempt_count());
3087 debug_show_held_locks(prev
);
3089 if (irqs_disabled())
3090 print_irqtrace_events(prev
);
3099 * Various schedule()-time debugging checks and statistics:
3101 static inline void schedule_debug(struct task_struct
*prev
)
3104 * Test if we are atomic. Since do_exit() needs to call into
3105 * schedule() atomically, we ignore that path for now.
3106 * Otherwise, whine if we are scheduling when we should not be.
3108 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
3109 __schedule_bug(prev
);
3112 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
3114 schedstat_inc(this_rq(), sched_count
);
3117 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
3119 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
3120 update_rq_clock(rq
);
3121 prev
->sched_class
->put_prev_task(rq
, prev
);
3125 * Pick up the highest-prio task:
3127 static inline struct task_struct
*
3128 pick_next_task(struct rq
*rq
)
3130 const struct sched_class
*class;
3131 struct task_struct
*p
;
3134 * Optimization: we know that if all tasks are in
3135 * the fair class we can call that function directly:
3137 if (likely(rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
3138 p
= fair_sched_class
.pick_next_task(rq
);
3143 for_each_class(class) {
3144 p
= class->pick_next_task(rq
);
3149 BUG(); /* the idle class will always have a runnable task */
3153 * __schedule() is the main scheduler function.
3155 static void __sched
__schedule(void)
3157 struct task_struct
*prev
, *next
;
3158 unsigned long *switch_count
;
3164 cpu
= smp_processor_id();
3166 rcu_note_context_switch(cpu
);
3169 schedule_debug(prev
);
3171 if (sched_feat(HRTICK
))
3174 raw_spin_lock_irq(&rq
->lock
);
3176 switch_count
= &prev
->nivcsw
;
3177 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
3178 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
3179 prev
->state
= TASK_RUNNING
;
3181 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
3185 * If a worker went to sleep, notify and ask workqueue
3186 * whether it wants to wake up a task to maintain
3189 if (prev
->flags
& PF_WQ_WORKER
) {
3190 struct task_struct
*to_wakeup
;
3192 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
3194 try_to_wake_up_local(to_wakeup
);
3197 switch_count
= &prev
->nvcsw
;
3200 pre_schedule(rq
, prev
);
3202 if (unlikely(!rq
->nr_running
))
3203 idle_balance(cpu
, rq
);
3205 put_prev_task(rq
, prev
);
3206 next
= pick_next_task(rq
);
3207 clear_tsk_need_resched(prev
);
3208 rq
->skip_clock_update
= 0;
3210 if (likely(prev
!= next
)) {
3215 context_switch(rq
, prev
, next
); /* unlocks the rq */
3217 * The context switch have flipped the stack from under us
3218 * and restored the local variables which were saved when
3219 * this task called schedule() in the past. prev == current
3220 * is still correct, but it can be moved to another cpu/rq.
3222 cpu
= smp_processor_id();
3225 raw_spin_unlock_irq(&rq
->lock
);
3229 preempt_enable_no_resched();
3234 static inline void sched_submit_work(struct task_struct
*tsk
)
3239 * If we are going to sleep and we have plugged IO queued,
3240 * make sure to submit it to avoid deadlocks.
3242 if (blk_needs_flush_plug(tsk
))
3243 blk_schedule_flush_plug(tsk
);
3246 asmlinkage
void __sched
schedule(void)
3248 struct task_struct
*tsk
= current
;
3250 sched_submit_work(tsk
);
3253 EXPORT_SYMBOL(schedule
);
3255 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3257 static inline bool owner_running(struct mutex
*lock
, struct task_struct
*owner
)
3259 if (lock
->owner
!= owner
)
3263 * Ensure we emit the owner->on_cpu, dereference _after_ checking
3264 * lock->owner still matches owner, if that fails, owner might
3265 * point to free()d memory, if it still matches, the rcu_read_lock()
3266 * ensures the memory stays valid.
3270 return owner
->on_cpu
;
3274 * Look out! "owner" is an entirely speculative pointer
3275 * access and not reliable.
3277 int mutex_spin_on_owner(struct mutex
*lock
, struct task_struct
*owner
)
3279 if (!sched_feat(OWNER_SPIN
))
3283 while (owner_running(lock
, owner
)) {
3287 arch_mutex_cpu_relax();
3292 * We break out the loop above on need_resched() and when the
3293 * owner changed, which is a sign for heavy contention. Return
3294 * success only when lock->owner is NULL.
3296 return lock
->owner
== NULL
;
3300 #ifdef CONFIG_PREEMPT
3302 * this is the entry point to schedule() from in-kernel preemption
3303 * off of preempt_enable. Kernel preemptions off return from interrupt
3304 * occur there and call schedule directly.
3306 asmlinkage
void __sched notrace
preempt_schedule(void)
3308 struct thread_info
*ti
= current_thread_info();
3311 * If there is a non-zero preempt_count or interrupts are disabled,
3312 * we do not want to preempt the current task. Just return..
3314 if (likely(ti
->preempt_count
|| irqs_disabled()))
3318 add_preempt_count_notrace(PREEMPT_ACTIVE
);
3320 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
3323 * Check again in case we missed a preemption opportunity
3324 * between schedule and now.
3327 } while (need_resched());
3329 EXPORT_SYMBOL(preempt_schedule
);
3332 * this is the entry point to schedule() from kernel preemption
3333 * off of irq context.
3334 * Note, that this is called and return with irqs disabled. This will
3335 * protect us against recursive calling from irq.
3337 asmlinkage
void __sched
preempt_schedule_irq(void)
3339 struct thread_info
*ti
= current_thread_info();
3341 /* Catch callers which need to be fixed */
3342 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
3345 add_preempt_count(PREEMPT_ACTIVE
);
3348 local_irq_disable();
3349 sub_preempt_count(PREEMPT_ACTIVE
);
3352 * Check again in case we missed a preemption opportunity
3353 * between schedule and now.
3356 } while (need_resched());
3359 #endif /* CONFIG_PREEMPT */
3361 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
3364 return try_to_wake_up(curr
->private, mode
, wake_flags
);
3366 EXPORT_SYMBOL(default_wake_function
);
3369 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3370 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3371 * number) then we wake all the non-exclusive tasks and one exclusive task.
3373 * There are circumstances in which we can try to wake a task which has already
3374 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3375 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3377 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
3378 int nr_exclusive
, int wake_flags
, void *key
)
3380 wait_queue_t
*curr
, *next
;
3382 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
3383 unsigned flags
= curr
->flags
;
3385 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
3386 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
3392 * __wake_up - wake up threads blocked on a waitqueue.
3394 * @mode: which threads
3395 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3396 * @key: is directly passed to the wakeup function
3398 * It may be assumed that this function implies a write memory barrier before
3399 * changing the task state if and only if any tasks are woken up.
3401 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
3402 int nr_exclusive
, void *key
)
3404 unsigned long flags
;
3406 spin_lock_irqsave(&q
->lock
, flags
);
3407 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
3408 spin_unlock_irqrestore(&q
->lock
, flags
);
3410 EXPORT_SYMBOL(__wake_up
);
3413 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3415 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
3417 __wake_up_common(q
, mode
, 1, 0, NULL
);
3419 EXPORT_SYMBOL_GPL(__wake_up_locked
);
3421 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
3423 __wake_up_common(q
, mode
, 1, 0, key
);
3425 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
3428 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
3430 * @mode: which threads
3431 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3432 * @key: opaque value to be passed to wakeup targets
3434 * The sync wakeup differs that the waker knows that it will schedule
3435 * away soon, so while the target thread will be woken up, it will not
3436 * be migrated to another CPU - ie. the two threads are 'synchronized'
3437 * with each other. This can prevent needless bouncing between CPUs.
3439 * On UP it can prevent extra preemption.
3441 * It may be assumed that this function implies a write memory barrier before
3442 * changing the task state if and only if any tasks are woken up.
3444 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
3445 int nr_exclusive
, void *key
)
3447 unsigned long flags
;
3448 int wake_flags
= WF_SYNC
;
3453 if (unlikely(!nr_exclusive
))
3456 spin_lock_irqsave(&q
->lock
, flags
);
3457 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
3458 spin_unlock_irqrestore(&q
->lock
, flags
);
3460 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
3463 * __wake_up_sync - see __wake_up_sync_key()
3465 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
3467 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
3469 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
3472 * complete: - signals a single thread waiting on this completion
3473 * @x: holds the state of this particular completion
3475 * This will wake up a single thread waiting on this completion. Threads will be
3476 * awakened in the same order in which they were queued.
3478 * See also complete_all(), wait_for_completion() and related routines.
3480 * It may be assumed that this function implies a write memory barrier before
3481 * changing the task state if and only if any tasks are woken up.
3483 void complete(struct completion
*x
)
3485 unsigned long flags
;
3487 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3489 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
3490 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3492 EXPORT_SYMBOL(complete
);
3495 * complete_all: - signals all threads waiting on this completion
3496 * @x: holds the state of this particular completion
3498 * This will wake up all threads waiting on this particular completion event.
3500 * It may be assumed that this function implies a write memory barrier before
3501 * changing the task state if and only if any tasks are woken up.
3503 void complete_all(struct completion
*x
)
3505 unsigned long flags
;
3507 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3508 x
->done
+= UINT_MAX
/2;
3509 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
3510 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3512 EXPORT_SYMBOL(complete_all
);
3514 static inline long __sched
3515 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
3518 DECLARE_WAITQUEUE(wait
, current
);
3520 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
3522 if (signal_pending_state(state
, current
)) {
3523 timeout
= -ERESTARTSYS
;
3526 __set_current_state(state
);
3527 spin_unlock_irq(&x
->wait
.lock
);
3528 timeout
= schedule_timeout(timeout
);
3529 spin_lock_irq(&x
->wait
.lock
);
3530 } while (!x
->done
&& timeout
);
3531 __remove_wait_queue(&x
->wait
, &wait
);
3536 return timeout
?: 1;
3540 wait_for_common(struct completion
*x
, long timeout
, int state
)
3544 spin_lock_irq(&x
->wait
.lock
);
3545 timeout
= do_wait_for_common(x
, timeout
, state
);
3546 spin_unlock_irq(&x
->wait
.lock
);
3551 * wait_for_completion: - waits for completion of a task
3552 * @x: holds the state of this particular completion
3554 * This waits to be signaled for completion of a specific task. It is NOT
3555 * interruptible and there is no timeout.
3557 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
3558 * and interrupt capability. Also see complete().
3560 void __sched
wait_for_completion(struct completion
*x
)
3562 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
3564 EXPORT_SYMBOL(wait_for_completion
);
3567 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
3568 * @x: holds the state of this particular completion
3569 * @timeout: timeout value in jiffies
3571 * This waits for either a completion of a specific task to be signaled or for a
3572 * specified timeout to expire. The timeout is in jiffies. It is not
3575 * The return value is 0 if timed out, and positive (at least 1, or number of
3576 * jiffies left till timeout) if completed.
3578 unsigned long __sched
3579 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
3581 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
3583 EXPORT_SYMBOL(wait_for_completion_timeout
);
3586 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
3587 * @x: holds the state of this particular completion
3589 * This waits for completion of a specific task to be signaled. It is
3592 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3594 int __sched
wait_for_completion_interruptible(struct completion
*x
)
3596 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
3597 if (t
== -ERESTARTSYS
)
3601 EXPORT_SYMBOL(wait_for_completion_interruptible
);
3604 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
3605 * @x: holds the state of this particular completion
3606 * @timeout: timeout value in jiffies
3608 * This waits for either a completion of a specific task to be signaled or for a
3609 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
3611 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3612 * positive (at least 1, or number of jiffies left till timeout) if completed.
3615 wait_for_completion_interruptible_timeout(struct completion
*x
,
3616 unsigned long timeout
)
3618 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
3620 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
3623 * wait_for_completion_killable: - waits for completion of a task (killable)
3624 * @x: holds the state of this particular completion
3626 * This waits to be signaled for completion of a specific task. It can be
3627 * interrupted by a kill signal.
3629 * The return value is -ERESTARTSYS if interrupted, 0 if completed.
3631 int __sched
wait_for_completion_killable(struct completion
*x
)
3633 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
3634 if (t
== -ERESTARTSYS
)
3638 EXPORT_SYMBOL(wait_for_completion_killable
);
3641 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
3642 * @x: holds the state of this particular completion
3643 * @timeout: timeout value in jiffies
3645 * This waits for either a completion of a specific task to be
3646 * signaled or for a specified timeout to expire. It can be
3647 * interrupted by a kill signal. The timeout is in jiffies.
3649 * The return value is -ERESTARTSYS if interrupted, 0 if timed out,
3650 * positive (at least 1, or number of jiffies left till timeout) if completed.
3653 wait_for_completion_killable_timeout(struct completion
*x
,
3654 unsigned long timeout
)
3656 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
3658 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
3661 * try_wait_for_completion - try to decrement a completion without blocking
3662 * @x: completion structure
3664 * Returns: 0 if a decrement cannot be done without blocking
3665 * 1 if a decrement succeeded.
3667 * If a completion is being used as a counting completion,
3668 * attempt to decrement the counter without blocking. This
3669 * enables us to avoid waiting if the resource the completion
3670 * is protecting is not available.
3672 bool try_wait_for_completion(struct completion
*x
)
3674 unsigned long flags
;
3677 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3682 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3685 EXPORT_SYMBOL(try_wait_for_completion
);
3688 * completion_done - Test to see if a completion has any waiters
3689 * @x: completion structure
3691 * Returns: 0 if there are waiters (wait_for_completion() in progress)
3692 * 1 if there are no waiters.
3695 bool completion_done(struct completion
*x
)
3697 unsigned long flags
;
3700 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3703 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3706 EXPORT_SYMBOL(completion_done
);
3709 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
3711 unsigned long flags
;
3714 init_waitqueue_entry(&wait
, current
);
3716 __set_current_state(state
);
3718 spin_lock_irqsave(&q
->lock
, flags
);
3719 __add_wait_queue(q
, &wait
);
3720 spin_unlock(&q
->lock
);
3721 timeout
= schedule_timeout(timeout
);
3722 spin_lock_irq(&q
->lock
);
3723 __remove_wait_queue(q
, &wait
);
3724 spin_unlock_irqrestore(&q
->lock
, flags
);
3729 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
3731 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3733 EXPORT_SYMBOL(interruptible_sleep_on
);
3736 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3738 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
3740 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
3742 void __sched
sleep_on(wait_queue_head_t
*q
)
3744 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
3746 EXPORT_SYMBOL(sleep_on
);
3748 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
3750 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
3752 EXPORT_SYMBOL(sleep_on_timeout
);
3754 #ifdef CONFIG_RT_MUTEXES
3757 * rt_mutex_setprio - set the current priority of a task
3759 * @prio: prio value (kernel-internal form)
3761 * This function changes the 'effective' priority of a task. It does
3762 * not touch ->normal_prio like __setscheduler().
3764 * Used by the rt_mutex code to implement priority inheritance logic.
3766 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
3768 int oldprio
, on_rq
, running
;
3770 const struct sched_class
*prev_class
;
3772 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
3774 rq
= __task_rq_lock(p
);
3776 trace_sched_pi_setprio(p
, prio
);
3778 prev_class
= p
->sched_class
;
3780 running
= task_current(rq
, p
);
3782 dequeue_task(rq
, p
, 0);
3784 p
->sched_class
->put_prev_task(rq
, p
);
3787 p
->sched_class
= &rt_sched_class
;
3789 p
->sched_class
= &fair_sched_class
;
3794 p
->sched_class
->set_curr_task(rq
);
3796 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
3798 check_class_changed(rq
, p
, prev_class
, oldprio
);
3799 __task_rq_unlock(rq
);
3804 void set_user_nice(struct task_struct
*p
, long nice
)
3806 int old_prio
, delta
, on_rq
;
3807 unsigned long flags
;
3810 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
3813 * We have to be careful, if called from sys_setpriority(),
3814 * the task might be in the middle of scheduling on another CPU.
3816 rq
= task_rq_lock(p
, &flags
);
3818 * The RT priorities are set via sched_setscheduler(), but we still
3819 * allow the 'normal' nice value to be set - but as expected
3820 * it wont have any effect on scheduling until the task is
3821 * SCHED_FIFO/SCHED_RR:
3823 if (task_has_rt_policy(p
)) {
3824 p
->static_prio
= NICE_TO_PRIO(nice
);
3829 dequeue_task(rq
, p
, 0);
3831 p
->static_prio
= NICE_TO_PRIO(nice
);
3834 p
->prio
= effective_prio(p
);
3835 delta
= p
->prio
- old_prio
;
3838 enqueue_task(rq
, p
, 0);
3840 * If the task increased its priority or is running and
3841 * lowered its priority, then reschedule its CPU:
3843 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3844 resched_task(rq
->curr
);
3847 task_rq_unlock(rq
, p
, &flags
);
3849 EXPORT_SYMBOL(set_user_nice
);
3852 * can_nice - check if a task can reduce its nice value
3856 int can_nice(const struct task_struct
*p
, const int nice
)
3858 /* convert nice value [19,-20] to rlimit style value [1,40] */
3859 int nice_rlim
= 20 - nice
;
3861 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3862 capable(CAP_SYS_NICE
));
3865 #ifdef __ARCH_WANT_SYS_NICE
3868 * sys_nice - change the priority of the current process.
3869 * @increment: priority increment
3871 * sys_setpriority is a more generic, but much slower function that
3872 * does similar things.
3874 SYSCALL_DEFINE1(nice
, int, increment
)
3879 * Setpriority might change our priority at the same moment.
3880 * We don't have to worry. Conceptually one call occurs first
3881 * and we have a single winner.
3883 if (increment
< -40)
3888 nice
= TASK_NICE(current
) + increment
;
3894 if (increment
< 0 && !can_nice(current
, nice
))
3897 retval
= security_task_setnice(current
, nice
);
3901 set_user_nice(current
, nice
);
3908 * task_prio - return the priority value of a given task.
3909 * @p: the task in question.
3911 * This is the priority value as seen by users in /proc.
3912 * RT tasks are offset by -200. Normal tasks are centered
3913 * around 0, value goes from -16 to +15.
3915 int task_prio(const struct task_struct
*p
)
3917 return p
->prio
- MAX_RT_PRIO
;
3921 * task_nice - return the nice value of a given task.
3922 * @p: the task in question.
3924 int task_nice(const struct task_struct
*p
)
3926 return TASK_NICE(p
);
3928 EXPORT_SYMBOL(task_nice
);
3931 * idle_cpu - is a given cpu idle currently?
3932 * @cpu: the processor in question.
3934 int idle_cpu(int cpu
)
3936 struct rq
*rq
= cpu_rq(cpu
);
3938 if (rq
->curr
!= rq
->idle
)
3945 if (!llist_empty(&rq
->wake_list
))
3953 * idle_task - return the idle task for a given cpu.
3954 * @cpu: the processor in question.
3956 struct task_struct
*idle_task(int cpu
)
3958 return cpu_rq(cpu
)->idle
;
3962 * find_process_by_pid - find a process with a matching PID value.
3963 * @pid: the pid in question.
3965 static struct task_struct
*find_process_by_pid(pid_t pid
)
3967 return pid
? find_task_by_vpid(pid
) : current
;
3970 /* Actually do priority change: must hold rq lock. */
3972 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
3975 p
->rt_priority
= prio
;
3976 p
->normal_prio
= normal_prio(p
);
3977 /* we are holding p->pi_lock already */
3978 p
->prio
= rt_mutex_getprio(p
);
3979 if (rt_prio(p
->prio
))
3980 p
->sched_class
= &rt_sched_class
;
3982 p
->sched_class
= &fair_sched_class
;
3987 * check the target process has a UID that matches the current process's
3989 static bool check_same_owner(struct task_struct
*p
)
3991 const struct cred
*cred
= current_cred(), *pcred
;
3995 pcred
= __task_cred(p
);
3996 if (cred
->user
->user_ns
== pcred
->user
->user_ns
)
3997 match
= (cred
->euid
== pcred
->euid
||
3998 cred
->euid
== pcred
->uid
);
4005 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
4006 const struct sched_param
*param
, bool user
)
4008 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4009 unsigned long flags
;
4010 const struct sched_class
*prev_class
;
4014 /* may grab non-irq protected spin_locks */
4015 BUG_ON(in_interrupt());
4017 /* double check policy once rq lock held */
4019 reset_on_fork
= p
->sched_reset_on_fork
;
4020 policy
= oldpolicy
= p
->policy
;
4022 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
4023 policy
&= ~SCHED_RESET_ON_FORK
;
4025 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4026 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4027 policy
!= SCHED_IDLE
)
4032 * Valid priorities for SCHED_FIFO and SCHED_RR are
4033 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4034 * SCHED_BATCH and SCHED_IDLE is 0.
4036 if (param
->sched_priority
< 0 ||
4037 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4038 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4040 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4044 * Allow unprivileged RT tasks to decrease priority:
4046 if (user
&& !capable(CAP_SYS_NICE
)) {
4047 if (rt_policy(policy
)) {
4048 unsigned long rlim_rtprio
=
4049 task_rlimit(p
, RLIMIT_RTPRIO
);
4051 /* can't set/change the rt policy */
4052 if (policy
!= p
->policy
&& !rlim_rtprio
)
4055 /* can't increase priority */
4056 if (param
->sched_priority
> p
->rt_priority
&&
4057 param
->sched_priority
> rlim_rtprio
)
4062 * Treat SCHED_IDLE as nice 20. Only allow a switch to
4063 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
4065 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
4066 if (!can_nice(p
, TASK_NICE(p
)))
4070 /* can't change other user's priorities */
4071 if (!check_same_owner(p
))
4074 /* Normal users shall not reset the sched_reset_on_fork flag */
4075 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
4080 retval
= security_task_setscheduler(p
);
4086 * make sure no PI-waiters arrive (or leave) while we are
4087 * changing the priority of the task:
4089 * To be able to change p->policy safely, the appropriate
4090 * runqueue lock must be held.
4092 rq
= task_rq_lock(p
, &flags
);
4095 * Changing the policy of the stop threads its a very bad idea
4097 if (p
== rq
->stop
) {
4098 task_rq_unlock(rq
, p
, &flags
);
4103 * If not changing anything there's no need to proceed further:
4105 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
4106 param
->sched_priority
== p
->rt_priority
))) {
4108 __task_rq_unlock(rq
);
4109 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4113 #ifdef CONFIG_RT_GROUP_SCHED
4116 * Do not allow realtime tasks into groups that have no runtime
4119 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
4120 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
4121 !task_group_is_autogroup(task_group(p
))) {
4122 task_rq_unlock(rq
, p
, &flags
);
4128 /* recheck policy now with rq lock held */
4129 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4130 policy
= oldpolicy
= -1;
4131 task_rq_unlock(rq
, p
, &flags
);
4135 running
= task_current(rq
, p
);
4137 deactivate_task(rq
, p
, 0);
4139 p
->sched_class
->put_prev_task(rq
, p
);
4141 p
->sched_reset_on_fork
= reset_on_fork
;
4144 prev_class
= p
->sched_class
;
4145 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4148 p
->sched_class
->set_curr_task(rq
);
4150 activate_task(rq
, p
, 0);
4152 check_class_changed(rq
, p
, prev_class
, oldprio
);
4153 task_rq_unlock(rq
, p
, &flags
);
4155 rt_mutex_adjust_pi(p
);
4161 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4162 * @p: the task in question.
4163 * @policy: new policy.
4164 * @param: structure containing the new RT priority.
4166 * NOTE that the task may be already dead.
4168 int sched_setscheduler(struct task_struct
*p
, int policy
,
4169 const struct sched_param
*param
)
4171 return __sched_setscheduler(p
, policy
, param
, true);
4173 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4176 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4177 * @p: the task in question.
4178 * @policy: new policy.
4179 * @param: structure containing the new RT priority.
4181 * Just like sched_setscheduler, only don't bother checking if the
4182 * current context has permission. For example, this is needed in
4183 * stop_machine(): we create temporary high priority worker threads,
4184 * but our caller might not have that capability.
4186 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
4187 const struct sched_param
*param
)
4189 return __sched_setscheduler(p
, policy
, param
, false);
4193 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4195 struct sched_param lparam
;
4196 struct task_struct
*p
;
4199 if (!param
|| pid
< 0)
4201 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4206 p
= find_process_by_pid(pid
);
4208 retval
= sched_setscheduler(p
, policy
, &lparam
);
4215 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4216 * @pid: the pid in question.
4217 * @policy: new policy.
4218 * @param: structure containing the new RT priority.
4220 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
4221 struct sched_param __user
*, param
)
4223 /* negative values for policy are not valid */
4227 return do_sched_setscheduler(pid
, policy
, param
);
4231 * sys_sched_setparam - set/change the RT priority of a thread
4232 * @pid: the pid in question.
4233 * @param: structure containing the new RT priority.
4235 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4237 return do_sched_setscheduler(pid
, -1, param
);
4241 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4242 * @pid: the pid in question.
4244 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
4246 struct task_struct
*p
;
4254 p
= find_process_by_pid(pid
);
4256 retval
= security_task_getscheduler(p
);
4259 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
4266 * sys_sched_getparam - get the RT priority of a thread
4267 * @pid: the pid in question.
4268 * @param: structure containing the RT priority.
4270 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4272 struct sched_param lp
;
4273 struct task_struct
*p
;
4276 if (!param
|| pid
< 0)
4280 p
= find_process_by_pid(pid
);
4285 retval
= security_task_getscheduler(p
);
4289 lp
.sched_priority
= p
->rt_priority
;
4293 * This one might sleep, we cannot do it with a spinlock held ...
4295 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4304 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4306 cpumask_var_t cpus_allowed
, new_mask
;
4307 struct task_struct
*p
;
4313 p
= find_process_by_pid(pid
);
4320 /* Prevent p going away */
4324 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4328 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4330 goto out_free_cpus_allowed
;
4333 if (!check_same_owner(p
) && !task_ns_capable(p
, CAP_SYS_NICE
))
4336 retval
= security_task_setscheduler(p
);
4340 cpuset_cpus_allowed(p
, cpus_allowed
);
4341 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4343 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4346 cpuset_cpus_allowed(p
, cpus_allowed
);
4347 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4349 * We must have raced with a concurrent cpuset
4350 * update. Just reset the cpus_allowed to the
4351 * cpuset's cpus_allowed
4353 cpumask_copy(new_mask
, cpus_allowed
);
4358 free_cpumask_var(new_mask
);
4359 out_free_cpus_allowed
:
4360 free_cpumask_var(cpus_allowed
);
4367 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4368 struct cpumask
*new_mask
)
4370 if (len
< cpumask_size())
4371 cpumask_clear(new_mask
);
4372 else if (len
> cpumask_size())
4373 len
= cpumask_size();
4375 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4379 * sys_sched_setaffinity - set the cpu affinity of a process
4380 * @pid: pid of the process
4381 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4382 * @user_mask_ptr: user-space pointer to the new cpu mask
4384 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4385 unsigned long __user
*, user_mask_ptr
)
4387 cpumask_var_t new_mask
;
4390 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4393 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4395 retval
= sched_setaffinity(pid
, new_mask
);
4396 free_cpumask_var(new_mask
);
4400 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4402 struct task_struct
*p
;
4403 unsigned long flags
;
4410 p
= find_process_by_pid(pid
);
4414 retval
= security_task_getscheduler(p
);
4418 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4419 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
4420 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4430 * sys_sched_getaffinity - get the cpu affinity of a process
4431 * @pid: pid of the process
4432 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4433 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4435 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4436 unsigned long __user
*, user_mask_ptr
)
4441 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4443 if (len
& (sizeof(unsigned long)-1))
4446 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4449 ret
= sched_getaffinity(pid
, mask
);
4451 size_t retlen
= min_t(size_t, len
, cpumask_size());
4453 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4458 free_cpumask_var(mask
);
4464 * sys_sched_yield - yield the current processor to other threads.
4466 * This function yields the current CPU to other tasks. If there are no
4467 * other threads running on this CPU then this function will return.
4469 SYSCALL_DEFINE0(sched_yield
)
4471 struct rq
*rq
= this_rq_lock();
4473 schedstat_inc(rq
, yld_count
);
4474 current
->sched_class
->yield_task(rq
);
4477 * Since we are going to call schedule() anyway, there's
4478 * no need to preempt or enable interrupts:
4480 __release(rq
->lock
);
4481 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4482 do_raw_spin_unlock(&rq
->lock
);
4483 preempt_enable_no_resched();
4490 static inline int should_resched(void)
4492 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
4495 static void __cond_resched(void)
4497 add_preempt_count(PREEMPT_ACTIVE
);
4499 sub_preempt_count(PREEMPT_ACTIVE
);
4502 int __sched
_cond_resched(void)
4504 if (should_resched()) {
4510 EXPORT_SYMBOL(_cond_resched
);
4513 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4514 * call schedule, and on return reacquire the lock.
4516 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4517 * operations here to prevent schedule() from being called twice (once via
4518 * spin_unlock(), once by hand).
4520 int __cond_resched_lock(spinlock_t
*lock
)
4522 int resched
= should_resched();
4525 lockdep_assert_held(lock
);
4527 if (spin_needbreak(lock
) || resched
) {
4538 EXPORT_SYMBOL(__cond_resched_lock
);
4540 int __sched
__cond_resched_softirq(void)
4542 BUG_ON(!in_softirq());
4544 if (should_resched()) {
4552 EXPORT_SYMBOL(__cond_resched_softirq
);
4555 * yield - yield the current processor to other threads.
4557 * This is a shortcut for kernel-space yielding - it marks the
4558 * thread runnable and calls sys_sched_yield().
4560 void __sched
yield(void)
4562 set_current_state(TASK_RUNNING
);
4565 EXPORT_SYMBOL(yield
);
4568 * yield_to - yield the current processor to another thread in
4569 * your thread group, or accelerate that thread toward the
4570 * processor it's on.
4572 * @preempt: whether task preemption is allowed or not
4574 * It's the caller's job to ensure that the target task struct
4575 * can't go away on us before we can do any checks.
4577 * Returns true if we indeed boosted the target task.
4579 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
4581 struct task_struct
*curr
= current
;
4582 struct rq
*rq
, *p_rq
;
4583 unsigned long flags
;
4586 local_irq_save(flags
);
4591 double_rq_lock(rq
, p_rq
);
4592 while (task_rq(p
) != p_rq
) {
4593 double_rq_unlock(rq
, p_rq
);
4597 if (!curr
->sched_class
->yield_to_task
)
4600 if (curr
->sched_class
!= p
->sched_class
)
4603 if (task_running(p_rq
, p
) || p
->state
)
4606 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4608 schedstat_inc(rq
, yld_count
);
4610 * Make p's CPU reschedule; pick_next_entity takes care of
4613 if (preempt
&& rq
!= p_rq
)
4614 resched_task(p_rq
->curr
);
4617 * We might have set it in task_yield_fair(), but are
4618 * not going to schedule(), so don't want to skip
4621 rq
->skip_clock_update
= 0;
4625 double_rq_unlock(rq
, p_rq
);
4626 local_irq_restore(flags
);
4633 EXPORT_SYMBOL_GPL(yield_to
);
4636 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4637 * that process accounting knows that this is a task in IO wait state.
4639 void __sched
io_schedule(void)
4641 struct rq
*rq
= raw_rq();
4643 delayacct_blkio_start();
4644 atomic_inc(&rq
->nr_iowait
);
4645 blk_flush_plug(current
);
4646 current
->in_iowait
= 1;
4648 current
->in_iowait
= 0;
4649 atomic_dec(&rq
->nr_iowait
);
4650 delayacct_blkio_end();
4652 EXPORT_SYMBOL(io_schedule
);
4654 long __sched
io_schedule_timeout(long timeout
)
4656 struct rq
*rq
= raw_rq();
4659 delayacct_blkio_start();
4660 atomic_inc(&rq
->nr_iowait
);
4661 blk_flush_plug(current
);
4662 current
->in_iowait
= 1;
4663 ret
= schedule_timeout(timeout
);
4664 current
->in_iowait
= 0;
4665 atomic_dec(&rq
->nr_iowait
);
4666 delayacct_blkio_end();
4671 * sys_sched_get_priority_max - return maximum RT priority.
4672 * @policy: scheduling class.
4674 * this syscall returns the maximum rt_priority that can be used
4675 * by a given scheduling class.
4677 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4684 ret
= MAX_USER_RT_PRIO
-1;
4696 * sys_sched_get_priority_min - return minimum RT priority.
4697 * @policy: scheduling class.
4699 * this syscall returns the minimum rt_priority that can be used
4700 * by a given scheduling class.
4702 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4720 * sys_sched_rr_get_interval - return the default timeslice of a process.
4721 * @pid: pid of the process.
4722 * @interval: userspace pointer to the timeslice value.
4724 * this syscall writes the default timeslice value of a given process
4725 * into the user-space timespec buffer. A value of '0' means infinity.
4727 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4728 struct timespec __user
*, interval
)
4730 struct task_struct
*p
;
4731 unsigned int time_slice
;
4732 unsigned long flags
;
4742 p
= find_process_by_pid(pid
);
4746 retval
= security_task_getscheduler(p
);
4750 rq
= task_rq_lock(p
, &flags
);
4751 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4752 task_rq_unlock(rq
, p
, &flags
);
4755 jiffies_to_timespec(time_slice
, &t
);
4756 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4764 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4766 void sched_show_task(struct task_struct
*p
)
4768 unsigned long free
= 0;
4771 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4772 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4773 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4774 #if BITS_PER_LONG == 32
4775 if (state
== TASK_RUNNING
)
4776 printk(KERN_CONT
" running ");
4778 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4780 if (state
== TASK_RUNNING
)
4781 printk(KERN_CONT
" running task ");
4783 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4785 #ifdef CONFIG_DEBUG_STACK_USAGE
4786 free
= stack_not_used(p
);
4788 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4789 task_pid_nr(p
), task_pid_nr(rcu_dereference(p
->real_parent
)),
4790 (unsigned long)task_thread_info(p
)->flags
);
4792 show_stack(p
, NULL
);
4795 void show_state_filter(unsigned long state_filter
)
4797 struct task_struct
*g
, *p
;
4799 #if BITS_PER_LONG == 32
4801 " task PC stack pid father\n");
4804 " task PC stack pid father\n");
4807 do_each_thread(g
, p
) {
4809 * reset the NMI-timeout, listing all files on a slow
4810 * console might take a lot of time:
4812 touch_nmi_watchdog();
4813 if (!state_filter
|| (p
->state
& state_filter
))
4815 } while_each_thread(g
, p
);
4817 touch_all_softlockup_watchdogs();
4819 #ifdef CONFIG_SCHED_DEBUG
4820 sysrq_sched_debug_show();
4824 * Only show locks if all tasks are dumped:
4827 debug_show_all_locks();
4830 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
4832 idle
->sched_class
= &idle_sched_class
;
4836 * init_idle - set up an idle thread for a given CPU
4837 * @idle: task in question
4838 * @cpu: cpu the idle task belongs to
4840 * NOTE: this function does not set the idle thread's NEED_RESCHED
4841 * flag, to make booting more robust.
4843 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
4845 struct rq
*rq
= cpu_rq(cpu
);
4846 unsigned long flags
;
4848 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4851 idle
->state
= TASK_RUNNING
;
4852 idle
->se
.exec_start
= sched_clock();
4854 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4856 * We're having a chicken and egg problem, even though we are
4857 * holding rq->lock, the cpu isn't yet set to this cpu so the
4858 * lockdep check in task_group() will fail.
4860 * Similar case to sched_fork(). / Alternatively we could
4861 * use task_rq_lock() here and obtain the other rq->lock.
4866 __set_task_cpu(idle
, cpu
);
4869 rq
->curr
= rq
->idle
= idle
;
4870 #if defined(CONFIG_SMP)
4873 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4875 /* Set the preempt count _outside_ the spinlocks! */
4876 task_thread_info(idle
)->preempt_count
= 0;
4879 * The idle tasks have their own, simple scheduling class:
4881 idle
->sched_class
= &idle_sched_class
;
4882 ftrace_graph_init_idle_task(idle
, cpu
);
4883 #if defined(CONFIG_SMP)
4884 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4889 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4891 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4892 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4894 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4895 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
4899 * This is how migration works:
4901 * 1) we invoke migration_cpu_stop() on the target CPU using
4903 * 2) stopper starts to run (implicitly forcing the migrated thread
4905 * 3) it checks whether the migrated task is still in the wrong runqueue.
4906 * 4) if it's in the wrong runqueue then the migration thread removes
4907 * it and puts it into the right queue.
4908 * 5) stopper completes and stop_one_cpu() returns and the migration
4913 * Change a given task's CPU affinity. Migrate the thread to a
4914 * proper CPU and schedule it away if the CPU it's executing on
4915 * is removed from the allowed bitmask.
4917 * NOTE: the caller must have a valid reference to the task, the
4918 * task must not exit() & deallocate itself prematurely. The
4919 * call is not atomic; no spinlocks may be held.
4921 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4923 unsigned long flags
;
4925 unsigned int dest_cpu
;
4928 rq
= task_rq_lock(p
, &flags
);
4930 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4933 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4938 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
)) {
4943 do_set_cpus_allowed(p
, new_mask
);
4945 /* Can the task run on the task's current CPU? If so, we're done */
4946 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4949 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4951 struct migration_arg arg
= { p
, dest_cpu
};
4952 /* Need help from migration thread: drop lock and wait. */
4953 task_rq_unlock(rq
, p
, &flags
);
4954 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4955 tlb_migrate_finish(p
->mm
);
4959 task_rq_unlock(rq
, p
, &flags
);
4963 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4966 * Move (not current) task off this cpu, onto dest cpu. We're doing
4967 * this because either it can't run here any more (set_cpus_allowed()
4968 * away from this CPU, or CPU going down), or because we're
4969 * attempting to rebalance this task on exec (sched_exec).
4971 * So we race with normal scheduler movements, but that's OK, as long
4972 * as the task is no longer on this CPU.
4974 * Returns non-zero if task was successfully migrated.
4976 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4978 struct rq
*rq_dest
, *rq_src
;
4981 if (unlikely(!cpu_active(dest_cpu
)))
4984 rq_src
= cpu_rq(src_cpu
);
4985 rq_dest
= cpu_rq(dest_cpu
);
4987 raw_spin_lock(&p
->pi_lock
);
4988 double_rq_lock(rq_src
, rq_dest
);
4989 /* Already moved. */
4990 if (task_cpu(p
) != src_cpu
)
4992 /* Affinity changed (again). */
4993 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4997 * If we're not on a rq, the next wake-up will ensure we're
5001 deactivate_task(rq_src
, p
, 0);
5002 set_task_cpu(p
, dest_cpu
);
5003 activate_task(rq_dest
, p
, 0);
5004 check_preempt_curr(rq_dest
, p
, 0);
5009 double_rq_unlock(rq_src
, rq_dest
);
5010 raw_spin_unlock(&p
->pi_lock
);
5015 * migration_cpu_stop - this will be executed by a highprio stopper thread
5016 * and performs thread migration by bumping thread off CPU then
5017 * 'pushing' onto another runqueue.
5019 static int migration_cpu_stop(void *data
)
5021 struct migration_arg
*arg
= data
;
5024 * The original target cpu might have gone down and we might
5025 * be on another cpu but it doesn't matter.
5027 local_irq_disable();
5028 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
5033 #ifdef CONFIG_HOTPLUG_CPU
5036 * Ensures that the idle task is using init_mm right before its cpu goes
5039 void idle_task_exit(void)
5041 struct mm_struct
*mm
= current
->active_mm
;
5043 BUG_ON(cpu_online(smp_processor_id()));
5046 switch_mm(mm
, &init_mm
, current
);
5051 * While a dead CPU has no uninterruptible tasks queued at this point,
5052 * it might still have a nonzero ->nr_uninterruptible counter, because
5053 * for performance reasons the counter is not stricly tracking tasks to
5054 * their home CPUs. So we just add the counter to another CPU's counter,
5055 * to keep the global sum constant after CPU-down:
5057 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5059 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
5061 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5062 rq_src
->nr_uninterruptible
= 0;
5066 * remove the tasks which were accounted by rq from calc_load_tasks.
5068 static void calc_global_load_remove(struct rq
*rq
)
5070 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
5071 rq
->calc_load_active
= 0;
5075 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5076 * try_to_wake_up()->select_task_rq().
5078 * Called with rq->lock held even though we'er in stop_machine() and
5079 * there's no concurrency possible, we hold the required locks anyway
5080 * because of lock validation efforts.
5082 static void migrate_tasks(unsigned int dead_cpu
)
5084 struct rq
*rq
= cpu_rq(dead_cpu
);
5085 struct task_struct
*next
, *stop
= rq
->stop
;
5089 * Fudge the rq selection such that the below task selection loop
5090 * doesn't get stuck on the currently eligible stop task.
5092 * We're currently inside stop_machine() and the rq is either stuck
5093 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5094 * either way we should never end up calling schedule() until we're
5099 /* Ensure any throttled groups are reachable by pick_next_task */
5100 unthrottle_offline_cfs_rqs(rq
);
5104 * There's this thread running, bail when that's the only
5107 if (rq
->nr_running
== 1)
5110 next
= pick_next_task(rq
);
5112 next
->sched_class
->put_prev_task(rq
, next
);
5114 /* Find suitable destination for @next, with force if needed. */
5115 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
5116 raw_spin_unlock(&rq
->lock
);
5118 __migrate_task(next
, dead_cpu
, dest_cpu
);
5120 raw_spin_lock(&rq
->lock
);
5126 #endif /* CONFIG_HOTPLUG_CPU */
5128 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5130 static struct ctl_table sd_ctl_dir
[] = {
5132 .procname
= "sched_domain",
5138 static struct ctl_table sd_ctl_root
[] = {
5140 .procname
= "kernel",
5142 .child
= sd_ctl_dir
,
5147 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5149 struct ctl_table
*entry
=
5150 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5155 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5157 struct ctl_table
*entry
;
5160 * In the intermediate directories, both the child directory and
5161 * procname are dynamically allocated and could fail but the mode
5162 * will always be set. In the lowest directory the names are
5163 * static strings and all have proc handlers.
5165 for (entry
= *tablep
; entry
->mode
; entry
++) {
5167 sd_free_ctl_entry(&entry
->child
);
5168 if (entry
->proc_handler
== NULL
)
5169 kfree(entry
->procname
);
5177 set_table_entry(struct ctl_table
*entry
,
5178 const char *procname
, void *data
, int maxlen
,
5179 umode_t mode
, proc_handler
*proc_handler
)
5181 entry
->procname
= procname
;
5183 entry
->maxlen
= maxlen
;
5185 entry
->proc_handler
= proc_handler
;
5188 static struct ctl_table
*
5189 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5191 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
5196 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5197 sizeof(long), 0644, proc_doulongvec_minmax
);
5198 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5199 sizeof(long), 0644, proc_doulongvec_minmax
);
5200 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5201 sizeof(int), 0644, proc_dointvec_minmax
);
5202 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5203 sizeof(int), 0644, proc_dointvec_minmax
);
5204 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5205 sizeof(int), 0644, proc_dointvec_minmax
);
5206 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5207 sizeof(int), 0644, proc_dointvec_minmax
);
5208 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5209 sizeof(int), 0644, proc_dointvec_minmax
);
5210 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5211 sizeof(int), 0644, proc_dointvec_minmax
);
5212 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5213 sizeof(int), 0644, proc_dointvec_minmax
);
5214 set_table_entry(&table
[9], "cache_nice_tries",
5215 &sd
->cache_nice_tries
,
5216 sizeof(int), 0644, proc_dointvec_minmax
);
5217 set_table_entry(&table
[10], "flags", &sd
->flags
,
5218 sizeof(int), 0644, proc_dointvec_minmax
);
5219 set_table_entry(&table
[11], "name", sd
->name
,
5220 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
5221 /* &table[12] is terminator */
5226 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5228 struct ctl_table
*entry
, *table
;
5229 struct sched_domain
*sd
;
5230 int domain_num
= 0, i
;
5233 for_each_domain(cpu
, sd
)
5235 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5240 for_each_domain(cpu
, sd
) {
5241 snprintf(buf
, 32, "domain%d", i
);
5242 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5244 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5251 static struct ctl_table_header
*sd_sysctl_header
;
5252 static void register_sched_domain_sysctl(void)
5254 int i
, cpu_num
= num_possible_cpus();
5255 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5258 WARN_ON(sd_ctl_dir
[0].child
);
5259 sd_ctl_dir
[0].child
= entry
;
5264 for_each_possible_cpu(i
) {
5265 snprintf(buf
, 32, "cpu%d", i
);
5266 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5268 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5272 WARN_ON(sd_sysctl_header
);
5273 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5276 /* may be called multiple times per register */
5277 static void unregister_sched_domain_sysctl(void)
5279 if (sd_sysctl_header
)
5280 unregister_sysctl_table(sd_sysctl_header
);
5281 sd_sysctl_header
= NULL
;
5282 if (sd_ctl_dir
[0].child
)
5283 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5286 static void register_sched_domain_sysctl(void)
5289 static void unregister_sched_domain_sysctl(void)
5294 static void set_rq_online(struct rq
*rq
)
5297 const struct sched_class
*class;
5299 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5302 for_each_class(class) {
5303 if (class->rq_online
)
5304 class->rq_online(rq
);
5309 static void set_rq_offline(struct rq
*rq
)
5312 const struct sched_class
*class;
5314 for_each_class(class) {
5315 if (class->rq_offline
)
5316 class->rq_offline(rq
);
5319 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5325 * migration_call - callback that gets triggered when a CPU is added.
5326 * Here we can start up the necessary migration thread for the new CPU.
5328 static int __cpuinit
5329 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5331 int cpu
= (long)hcpu
;
5332 unsigned long flags
;
5333 struct rq
*rq
= cpu_rq(cpu
);
5335 switch (action
& ~CPU_TASKS_FROZEN
) {
5337 case CPU_UP_PREPARE
:
5338 rq
->calc_load_update
= calc_load_update
;
5342 /* Update our root-domain */
5343 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5345 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5349 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5352 #ifdef CONFIG_HOTPLUG_CPU
5354 sched_ttwu_pending();
5355 /* Update our root-domain */
5356 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5358 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5362 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5363 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5365 migrate_nr_uninterruptible(rq
);
5366 calc_global_load_remove(rq
);
5371 update_max_interval();
5377 * Register at high priority so that task migration (migrate_all_tasks)
5378 * happens before everything else. This has to be lower priority than
5379 * the notifier in the perf_event subsystem, though.
5381 static struct notifier_block __cpuinitdata migration_notifier
= {
5382 .notifier_call
= migration_call
,
5383 .priority
= CPU_PRI_MIGRATION
,
5386 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
5387 unsigned long action
, void *hcpu
)
5389 switch (action
& ~CPU_TASKS_FROZEN
) {
5391 case CPU_DOWN_FAILED
:
5392 set_cpu_active((long)hcpu
, true);
5399 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
5400 unsigned long action
, void *hcpu
)
5402 switch (action
& ~CPU_TASKS_FROZEN
) {
5403 case CPU_DOWN_PREPARE
:
5404 set_cpu_active((long)hcpu
, false);
5411 static int __init
migration_init(void)
5413 void *cpu
= (void *)(long)smp_processor_id();
5416 /* Initialize migration for the boot CPU */
5417 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5418 BUG_ON(err
== NOTIFY_BAD
);
5419 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5420 register_cpu_notifier(&migration_notifier
);
5422 /* Register cpu active notifiers */
5423 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5424 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5428 early_initcall(migration_init
);
5433 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5435 #ifdef CONFIG_SCHED_DEBUG
5437 static __read_mostly
int sched_domain_debug_enabled
;
5439 static int __init
sched_domain_debug_setup(char *str
)
5441 sched_domain_debug_enabled
= 1;
5445 early_param("sched_debug", sched_domain_debug_setup
);
5447 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5448 struct cpumask
*groupmask
)
5450 struct sched_group
*group
= sd
->groups
;
5453 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5454 cpumask_clear(groupmask
);
5456 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5458 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5459 printk("does not load-balance\n");
5461 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5466 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5468 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5469 printk(KERN_ERR
"ERROR: domain->span does not contain "
5472 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5473 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5477 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5481 printk(KERN_ERR
"ERROR: group is NULL\n");
5485 if (!group
->sgp
->power
) {
5486 printk(KERN_CONT
"\n");
5487 printk(KERN_ERR
"ERROR: domain->cpu_power not "
5492 if (!cpumask_weight(sched_group_cpus(group
))) {
5493 printk(KERN_CONT
"\n");
5494 printk(KERN_ERR
"ERROR: empty group\n");
5498 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5499 printk(KERN_CONT
"\n");
5500 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5504 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5506 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
5508 printk(KERN_CONT
" %s", str
);
5509 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
5510 printk(KERN_CONT
" (cpu_power = %d)",
5514 group
= group
->next
;
5515 } while (group
!= sd
->groups
);
5516 printk(KERN_CONT
"\n");
5518 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5519 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5522 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5523 printk(KERN_ERR
"ERROR: parent span is not a superset "
5524 "of domain->span\n");
5528 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5532 if (!sched_domain_debug_enabled
)
5536 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5540 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5543 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5551 #else /* !CONFIG_SCHED_DEBUG */
5552 # define sched_domain_debug(sd, cpu) do { } while (0)
5553 #endif /* CONFIG_SCHED_DEBUG */
5555 static int sd_degenerate(struct sched_domain
*sd
)
5557 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5560 /* Following flags need at least 2 groups */
5561 if (sd
->flags
& (SD_LOAD_BALANCE
|
5562 SD_BALANCE_NEWIDLE
|
5566 SD_SHARE_PKG_RESOURCES
)) {
5567 if (sd
->groups
!= sd
->groups
->next
)
5571 /* Following flags don't use groups */
5572 if (sd
->flags
& (SD_WAKE_AFFINE
))
5579 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5581 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5583 if (sd_degenerate(parent
))
5586 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5589 /* Flags needing groups don't count if only 1 group in parent */
5590 if (parent
->groups
== parent
->groups
->next
) {
5591 pflags
&= ~(SD_LOAD_BALANCE
|
5592 SD_BALANCE_NEWIDLE
|
5596 SD_SHARE_PKG_RESOURCES
);
5597 if (nr_node_ids
== 1)
5598 pflags
&= ~SD_SERIALIZE
;
5600 if (~cflags
& pflags
)
5606 static void free_rootdomain(struct rcu_head
*rcu
)
5608 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5610 cpupri_cleanup(&rd
->cpupri
);
5611 free_cpumask_var(rd
->rto_mask
);
5612 free_cpumask_var(rd
->online
);
5613 free_cpumask_var(rd
->span
);
5617 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5619 struct root_domain
*old_rd
= NULL
;
5620 unsigned long flags
;
5622 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5627 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5630 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5633 * If we dont want to free the old_rt yet then
5634 * set old_rd to NULL to skip the freeing later
5637 if (!atomic_dec_and_test(&old_rd
->refcount
))
5641 atomic_inc(&rd
->refcount
);
5644 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5645 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5648 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5651 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5654 static int init_rootdomain(struct root_domain
*rd
)
5656 memset(rd
, 0, sizeof(*rd
));
5658 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5660 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5662 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5665 if (cpupri_init(&rd
->cpupri
) != 0)
5670 free_cpumask_var(rd
->rto_mask
);
5672 free_cpumask_var(rd
->online
);
5674 free_cpumask_var(rd
->span
);
5680 * By default the system creates a single root-domain with all cpus as
5681 * members (mimicking the global state we have today).
5683 struct root_domain def_root_domain
;
5685 static void init_defrootdomain(void)
5687 init_rootdomain(&def_root_domain
);
5689 atomic_set(&def_root_domain
.refcount
, 1);
5692 static struct root_domain
*alloc_rootdomain(void)
5694 struct root_domain
*rd
;
5696 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5700 if (init_rootdomain(rd
) != 0) {
5708 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
5710 struct sched_group
*tmp
, *first
;
5719 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
5724 } while (sg
!= first
);
5727 static void free_sched_domain(struct rcu_head
*rcu
)
5729 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5732 * If its an overlapping domain it has private groups, iterate and
5735 if (sd
->flags
& SD_OVERLAP
) {
5736 free_sched_groups(sd
->groups
, 1);
5737 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5738 kfree(sd
->groups
->sgp
);
5744 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5746 call_rcu(&sd
->rcu
, free_sched_domain
);
5749 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5751 for (; sd
; sd
= sd
->parent
)
5752 destroy_sched_domain(sd
, cpu
);
5756 * Keep a special pointer to the highest sched_domain that has
5757 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5758 * allows us to avoid some pointer chasing select_idle_sibling().
5760 * Also keep a unique ID per domain (we use the first cpu number in
5761 * the cpumask of the domain), this allows us to quickly tell if
5762 * two cpus are in the same cache domain, see ttwu_share_cache().
5764 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5765 DEFINE_PER_CPU(int, sd_llc_id
);
5767 static void update_top_cache_domain(int cpu
)
5769 struct sched_domain
*sd
;
5772 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5774 id
= cpumask_first(sched_domain_span(sd
));
5776 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5777 per_cpu(sd_llc_id
, cpu
) = id
;
5781 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5782 * hold the hotplug lock.
5785 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5787 struct rq
*rq
= cpu_rq(cpu
);
5788 struct sched_domain
*tmp
;
5790 /* Remove the sched domains which do not contribute to scheduling. */
5791 for (tmp
= sd
; tmp
; ) {
5792 struct sched_domain
*parent
= tmp
->parent
;
5796 if (sd_parent_degenerate(tmp
, parent
)) {
5797 tmp
->parent
= parent
->parent
;
5799 parent
->parent
->child
= tmp
;
5800 destroy_sched_domain(parent
, cpu
);
5805 if (sd
&& sd_degenerate(sd
)) {
5808 destroy_sched_domain(tmp
, cpu
);
5813 sched_domain_debug(sd
, cpu
);
5815 rq_attach_root(rq
, rd
);
5817 rcu_assign_pointer(rq
->sd
, sd
);
5818 destroy_sched_domains(tmp
, cpu
);
5820 update_top_cache_domain(cpu
);
5823 /* cpus with isolated domains */
5824 static cpumask_var_t cpu_isolated_map
;
5826 /* Setup the mask of cpus configured for isolated domains */
5827 static int __init
isolated_cpu_setup(char *str
)
5829 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5830 cpulist_parse(str
, cpu_isolated_map
);
5834 __setup("isolcpus=", isolated_cpu_setup
);
5839 * find_next_best_node - find the next node to include in a sched_domain
5840 * @node: node whose sched_domain we're building
5841 * @used_nodes: nodes already in the sched_domain
5843 * Find the next node to include in a given scheduling domain. Simply
5844 * finds the closest node not already in the @used_nodes map.
5846 * Should use nodemask_t.
5848 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
5850 int i
, n
, val
, min_val
, best_node
= -1;
5854 for (i
= 0; i
< nr_node_ids
; i
++) {
5855 /* Start at @node */
5856 n
= (node
+ i
) % nr_node_ids
;
5858 if (!nr_cpus_node(n
))
5861 /* Skip already used nodes */
5862 if (node_isset(n
, *used_nodes
))
5865 /* Simple min distance search */
5866 val
= node_distance(node
, n
);
5868 if (val
< min_val
) {
5874 if (best_node
!= -1)
5875 node_set(best_node
, *used_nodes
);
5880 * sched_domain_node_span - get a cpumask for a node's sched_domain
5881 * @node: node whose cpumask we're constructing
5882 * @span: resulting cpumask
5884 * Given a node, construct a good cpumask for its sched_domain to span. It
5885 * should be one that prevents unnecessary balancing, but also spreads tasks
5888 static void sched_domain_node_span(int node
, struct cpumask
*span
)
5890 nodemask_t used_nodes
;
5893 cpumask_clear(span
);
5894 nodes_clear(used_nodes
);
5896 cpumask_or(span
, span
, cpumask_of_node(node
));
5897 node_set(node
, used_nodes
);
5899 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
5900 int next_node
= find_next_best_node(node
, &used_nodes
);
5903 cpumask_or(span
, span
, cpumask_of_node(next_node
));
5907 static const struct cpumask
*cpu_node_mask(int cpu
)
5909 lockdep_assert_held(&sched_domains_mutex
);
5911 sched_domain_node_span(cpu_to_node(cpu
), sched_domains_tmpmask
);
5913 return sched_domains_tmpmask
;
5916 static const struct cpumask
*cpu_allnodes_mask(int cpu
)
5918 return cpu_possible_mask
;
5920 #endif /* CONFIG_NUMA */
5922 static const struct cpumask
*cpu_cpu_mask(int cpu
)
5924 return cpumask_of_node(cpu_to_node(cpu
));
5927 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
5930 struct sched_domain
**__percpu sd
;
5931 struct sched_group
**__percpu sg
;
5932 struct sched_group_power
**__percpu sgp
;
5936 struct sched_domain
** __percpu sd
;
5937 struct root_domain
*rd
;
5947 struct sched_domain_topology_level
;
5949 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
5950 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
5952 #define SDTL_OVERLAP 0x01
5954 struct sched_domain_topology_level
{
5955 sched_domain_init_f init
;
5956 sched_domain_mask_f mask
;
5958 struct sd_data data
;
5962 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5964 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5965 const struct cpumask
*span
= sched_domain_span(sd
);
5966 struct cpumask
*covered
= sched_domains_tmpmask
;
5967 struct sd_data
*sdd
= sd
->private;
5968 struct sched_domain
*child
;
5971 cpumask_clear(covered
);
5973 for_each_cpu(i
, span
) {
5974 struct cpumask
*sg_span
;
5976 if (cpumask_test_cpu(i
, covered
))
5979 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5980 GFP_KERNEL
, cpu_to_node(cpu
));
5985 sg_span
= sched_group_cpus(sg
);
5987 child
= *per_cpu_ptr(sdd
->sd
, i
);
5989 child
= child
->child
;
5990 cpumask_copy(sg_span
, sched_domain_span(child
));
5992 cpumask_set_cpu(i
, sg_span
);
5994 cpumask_or(covered
, covered
, sg_span
);
5996 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, cpumask_first(sg_span
));
5997 atomic_inc(&sg
->sgp
->ref
);
5999 if (cpumask_test_cpu(cpu
, sg_span
))
6009 sd
->groups
= groups
;
6014 free_sched_groups(first
, 0);
6019 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
6021 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
6022 struct sched_domain
*child
= sd
->child
;
6025 cpu
= cpumask_first(sched_domain_span(child
));
6028 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
6029 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
6030 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
6037 * build_sched_groups will build a circular linked list of the groups
6038 * covered by the given span, and will set each group's ->cpumask correctly,
6039 * and ->cpu_power to 0.
6041 * Assumes the sched_domain tree is fully constructed
6044 build_sched_groups(struct sched_domain
*sd
, int cpu
)
6046 struct sched_group
*first
= NULL
, *last
= NULL
;
6047 struct sd_data
*sdd
= sd
->private;
6048 const struct cpumask
*span
= sched_domain_span(sd
);
6049 struct cpumask
*covered
;
6052 get_group(cpu
, sdd
, &sd
->groups
);
6053 atomic_inc(&sd
->groups
->ref
);
6055 if (cpu
!= cpumask_first(sched_domain_span(sd
)))
6058 lockdep_assert_held(&sched_domains_mutex
);
6059 covered
= sched_domains_tmpmask
;
6061 cpumask_clear(covered
);
6063 for_each_cpu(i
, span
) {
6064 struct sched_group
*sg
;
6065 int group
= get_group(i
, sdd
, &sg
);
6068 if (cpumask_test_cpu(i
, covered
))
6071 cpumask_clear(sched_group_cpus(sg
));
6074 for_each_cpu(j
, span
) {
6075 if (get_group(j
, sdd
, NULL
) != group
)
6078 cpumask_set_cpu(j
, covered
);
6079 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6094 * Initialize sched groups cpu_power.
6096 * cpu_power indicates the capacity of sched group, which is used while
6097 * distributing the load between different sched groups in a sched domain.
6098 * Typically cpu_power for all the groups in a sched domain will be same unless
6099 * there are asymmetries in the topology. If there are asymmetries, group
6100 * having more cpu_power will pickup more load compared to the group having
6103 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6105 struct sched_group
*sg
= sd
->groups
;
6107 WARN_ON(!sd
|| !sg
);
6110 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
6112 } while (sg
!= sd
->groups
);
6114 if (cpu
!= group_first_cpu(sg
))
6117 update_group_power(sd
, cpu
);
6118 atomic_set(&sg
->sgp
->nr_busy_cpus
, sg
->group_weight
);
6121 int __weak
arch_sd_sibling_asym_packing(void)
6123 return 0*SD_ASYM_PACKING
;
6127 * Initializers for schedule domains
6128 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6131 #ifdef CONFIG_SCHED_DEBUG
6132 # define SD_INIT_NAME(sd, type) sd->name = #type
6134 # define SD_INIT_NAME(sd, type) do { } while (0)
6137 #define SD_INIT_FUNC(type) \
6138 static noinline struct sched_domain * \
6139 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
6141 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
6142 *sd = SD_##type##_INIT; \
6143 SD_INIT_NAME(sd, type); \
6144 sd->private = &tl->data; \
6150 SD_INIT_FUNC(ALLNODES
)
6153 #ifdef CONFIG_SCHED_SMT
6154 SD_INIT_FUNC(SIBLING
)
6156 #ifdef CONFIG_SCHED_MC
6159 #ifdef CONFIG_SCHED_BOOK
6163 static int default_relax_domain_level
= -1;
6164 int sched_domain_level_max
;
6166 static int __init
setup_relax_domain_level(char *str
)
6170 val
= simple_strtoul(str
, NULL
, 0);
6171 if (val
< sched_domain_level_max
)
6172 default_relax_domain_level
= val
;
6176 __setup("relax_domain_level=", setup_relax_domain_level
);
6178 static void set_domain_attribute(struct sched_domain
*sd
,
6179 struct sched_domain_attr
*attr
)
6183 if (!attr
|| attr
->relax_domain_level
< 0) {
6184 if (default_relax_domain_level
< 0)
6187 request
= default_relax_domain_level
;
6189 request
= attr
->relax_domain_level
;
6190 if (request
< sd
->level
) {
6191 /* turn off idle balance on this domain */
6192 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6194 /* turn on idle balance on this domain */
6195 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6199 static void __sdt_free(const struct cpumask
*cpu_map
);
6200 static int __sdt_alloc(const struct cpumask
*cpu_map
);
6202 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6203 const struct cpumask
*cpu_map
)
6207 if (!atomic_read(&d
->rd
->refcount
))
6208 free_rootdomain(&d
->rd
->rcu
); /* fall through */
6210 free_percpu(d
->sd
); /* fall through */
6212 __sdt_free(cpu_map
); /* fall through */
6218 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6219 const struct cpumask
*cpu_map
)
6221 memset(d
, 0, sizeof(*d
));
6223 if (__sdt_alloc(cpu_map
))
6224 return sa_sd_storage
;
6225 d
->sd
= alloc_percpu(struct sched_domain
*);
6227 return sa_sd_storage
;
6228 d
->rd
= alloc_rootdomain();
6231 return sa_rootdomain
;
6235 * NULL the sd_data elements we've used to build the sched_domain and
6236 * sched_group structure so that the subsequent __free_domain_allocs()
6237 * will not free the data we're using.
6239 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
6241 struct sd_data
*sdd
= sd
->private;
6243 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
6244 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
6246 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
6247 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
6249 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
6250 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
6253 #ifdef CONFIG_SCHED_SMT
6254 static const struct cpumask
*cpu_smt_mask(int cpu
)
6256 return topology_thread_cpumask(cpu
);
6261 * Topology list, bottom-up.
6263 static struct sched_domain_topology_level default_topology
[] = {
6264 #ifdef CONFIG_SCHED_SMT
6265 { sd_init_SIBLING
, cpu_smt_mask
, },
6267 #ifdef CONFIG_SCHED_MC
6268 { sd_init_MC
, cpu_coregroup_mask
, },
6270 #ifdef CONFIG_SCHED_BOOK
6271 { sd_init_BOOK
, cpu_book_mask
, },
6273 { sd_init_CPU
, cpu_cpu_mask
, },
6275 { sd_init_NODE
, cpu_node_mask
, SDTL_OVERLAP
, },
6276 { sd_init_ALLNODES
, cpu_allnodes_mask
, },
6281 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6283 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6285 struct sched_domain_topology_level
*tl
;
6288 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6289 struct sd_data
*sdd
= &tl
->data
;
6291 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6295 sdd
->sg
= alloc_percpu(struct sched_group
*);
6299 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
6303 for_each_cpu(j
, cpu_map
) {
6304 struct sched_domain
*sd
;
6305 struct sched_group
*sg
;
6306 struct sched_group_power
*sgp
;
6308 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6309 GFP_KERNEL
, cpu_to_node(j
));
6313 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6315 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6316 GFP_KERNEL
, cpu_to_node(j
));
6320 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6322 sgp
= kzalloc_node(sizeof(struct sched_group_power
),
6323 GFP_KERNEL
, cpu_to_node(j
));
6327 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
6334 static void __sdt_free(const struct cpumask
*cpu_map
)
6336 struct sched_domain_topology_level
*tl
;
6339 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6340 struct sd_data
*sdd
= &tl
->data
;
6342 for_each_cpu(j
, cpu_map
) {
6343 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, j
);
6344 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6345 free_sched_groups(sd
->groups
, 0);
6346 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6347 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6348 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
6350 free_percpu(sdd
->sd
);
6351 free_percpu(sdd
->sg
);
6352 free_percpu(sdd
->sgp
);
6356 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6357 struct s_data
*d
, const struct cpumask
*cpu_map
,
6358 struct sched_domain_attr
*attr
, struct sched_domain
*child
,
6361 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
6365 set_domain_attribute(sd
, attr
);
6366 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6368 sd
->level
= child
->level
+ 1;
6369 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6378 * Build sched domains for a given set of cpus and attach the sched domains
6379 * to the individual cpus
6381 static int build_sched_domains(const struct cpumask
*cpu_map
,
6382 struct sched_domain_attr
*attr
)
6384 enum s_alloc alloc_state
= sa_none
;
6385 struct sched_domain
*sd
;
6387 int i
, ret
= -ENOMEM
;
6389 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6390 if (alloc_state
!= sa_rootdomain
)
6393 /* Set up domains for cpus specified by the cpu_map. */
6394 for_each_cpu(i
, cpu_map
) {
6395 struct sched_domain_topology_level
*tl
;
6398 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
6399 sd
= build_sched_domain(tl
, &d
, cpu_map
, attr
, sd
, i
);
6400 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6401 sd
->flags
|= SD_OVERLAP
;
6402 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6409 *per_cpu_ptr(d
.sd
, i
) = sd
;
6412 /* Build the groups for the domains */
6413 for_each_cpu(i
, cpu_map
) {
6414 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6415 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6416 if (sd
->flags
& SD_OVERLAP
) {
6417 if (build_overlap_sched_groups(sd
, i
))
6420 if (build_sched_groups(sd
, i
))
6426 /* Calculate CPU power for physical packages and nodes */
6427 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6428 if (!cpumask_test_cpu(i
, cpu_map
))
6431 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6432 claim_allocations(i
, sd
);
6433 init_sched_groups_power(i
, sd
);
6437 /* Attach the domains */
6439 for_each_cpu(i
, cpu_map
) {
6440 sd
= *per_cpu_ptr(d
.sd
, i
);
6441 cpu_attach_domain(sd
, d
.rd
, i
);
6447 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6451 static cpumask_var_t
*doms_cur
; /* current sched domains */
6452 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6453 static struct sched_domain_attr
*dattr_cur
;
6454 /* attribues of custom domains in 'doms_cur' */
6457 * Special case: If a kmalloc of a doms_cur partition (array of
6458 * cpumask) fails, then fallback to a single sched domain,
6459 * as determined by the single cpumask fallback_doms.
6461 static cpumask_var_t fallback_doms
;
6464 * arch_update_cpu_topology lets virtualized architectures update the
6465 * cpu core maps. It is supposed to return 1 if the topology changed
6466 * or 0 if it stayed the same.
6468 int __attribute__((weak
)) arch_update_cpu_topology(void)
6473 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6476 cpumask_var_t
*doms
;
6478 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6481 for (i
= 0; i
< ndoms
; i
++) {
6482 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6483 free_sched_domains(doms
, i
);
6490 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6493 for (i
= 0; i
< ndoms
; i
++)
6494 free_cpumask_var(doms
[i
]);
6499 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6500 * For now this just excludes isolated cpus, but could be used to
6501 * exclude other special cases in the future.
6503 static int init_sched_domains(const struct cpumask
*cpu_map
)
6507 arch_update_cpu_topology();
6509 doms_cur
= alloc_sched_domains(ndoms_cur
);
6511 doms_cur
= &fallback_doms
;
6512 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6514 err
= build_sched_domains(doms_cur
[0], NULL
);
6515 register_sched_domain_sysctl();
6521 * Detach sched domains from a group of cpus specified in cpu_map
6522 * These cpus will now be attached to the NULL domain
6524 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6529 for_each_cpu(i
, cpu_map
)
6530 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6534 /* handle null as "default" */
6535 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6536 struct sched_domain_attr
*new, int idx_new
)
6538 struct sched_domain_attr tmp
;
6545 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6546 new ? (new + idx_new
) : &tmp
,
6547 sizeof(struct sched_domain_attr
));
6551 * Partition sched domains as specified by the 'ndoms_new'
6552 * cpumasks in the array doms_new[] of cpumasks. This compares
6553 * doms_new[] to the current sched domain partitioning, doms_cur[].
6554 * It destroys each deleted domain and builds each new domain.
6556 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6557 * The masks don't intersect (don't overlap.) We should setup one
6558 * sched domain for each mask. CPUs not in any of the cpumasks will
6559 * not be load balanced. If the same cpumask appears both in the
6560 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6563 * The passed in 'doms_new' should be allocated using
6564 * alloc_sched_domains. This routine takes ownership of it and will
6565 * free_sched_domains it when done with it. If the caller failed the
6566 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6567 * and partition_sched_domains() will fallback to the single partition
6568 * 'fallback_doms', it also forces the domains to be rebuilt.
6570 * If doms_new == NULL it will be replaced with cpu_online_mask.
6571 * ndoms_new == 0 is a special case for destroying existing domains,
6572 * and it will not create the default domain.
6574 * Call with hotplug lock held
6576 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6577 struct sched_domain_attr
*dattr_new
)
6582 mutex_lock(&sched_domains_mutex
);
6584 /* always unregister in case we don't destroy any domains */
6585 unregister_sched_domain_sysctl();
6587 /* Let architecture update cpu core mappings. */
6588 new_topology
= arch_update_cpu_topology();
6590 n
= doms_new
? ndoms_new
: 0;
6592 /* Destroy deleted domains */
6593 for (i
= 0; i
< ndoms_cur
; i
++) {
6594 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6595 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6596 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6599 /* no match - a current sched domain not in new doms_new[] */
6600 detach_destroy_domains(doms_cur
[i
]);
6605 if (doms_new
== NULL
) {
6607 doms_new
= &fallback_doms
;
6608 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6609 WARN_ON_ONCE(dattr_new
);
6612 /* Build new domains */
6613 for (i
= 0; i
< ndoms_new
; i
++) {
6614 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
6615 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6616 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6619 /* no match - add a new doms_new */
6620 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6625 /* Remember the new sched domains */
6626 if (doms_cur
!= &fallback_doms
)
6627 free_sched_domains(doms_cur
, ndoms_cur
);
6628 kfree(dattr_cur
); /* kfree(NULL) is safe */
6629 doms_cur
= doms_new
;
6630 dattr_cur
= dattr_new
;
6631 ndoms_cur
= ndoms_new
;
6633 register_sched_domain_sysctl();
6635 mutex_unlock(&sched_domains_mutex
);
6638 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
6639 static void reinit_sched_domains(void)
6643 /* Destroy domains first to force the rebuild */
6644 partition_sched_domains(0, NULL
, NULL
);
6646 rebuild_sched_domains();
6650 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
6652 unsigned int level
= 0;
6654 if (sscanf(buf
, "%u", &level
) != 1)
6658 * level is always be positive so don't check for
6659 * level < POWERSAVINGS_BALANCE_NONE which is 0
6660 * What happens on 0 or 1 byte write,
6661 * need to check for count as well?
6664 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
6668 sched_smt_power_savings
= level
;
6670 sched_mc_power_savings
= level
;
6672 reinit_sched_domains();
6677 #ifdef CONFIG_SCHED_MC
6678 static ssize_t
sched_mc_power_savings_show(struct device
*dev
,
6679 struct device_attribute
*attr
,
6682 return sprintf(buf
, "%u\n", sched_mc_power_savings
);
6684 static ssize_t
sched_mc_power_savings_store(struct device
*dev
,
6685 struct device_attribute
*attr
,
6686 const char *buf
, size_t count
)
6688 return sched_power_savings_store(buf
, count
, 0);
6690 static DEVICE_ATTR(sched_mc_power_savings
, 0644,
6691 sched_mc_power_savings_show
,
6692 sched_mc_power_savings_store
);
6695 #ifdef CONFIG_SCHED_SMT
6696 static ssize_t
sched_smt_power_savings_show(struct device
*dev
,
6697 struct device_attribute
*attr
,
6700 return sprintf(buf
, "%u\n", sched_smt_power_savings
);
6702 static ssize_t
sched_smt_power_savings_store(struct device
*dev
,
6703 struct device_attribute
*attr
,
6704 const char *buf
, size_t count
)
6706 return sched_power_savings_store(buf
, count
, 1);
6708 static DEVICE_ATTR(sched_smt_power_savings
, 0644,
6709 sched_smt_power_savings_show
,
6710 sched_smt_power_savings_store
);
6713 int __init
sched_create_sysfs_power_savings_entries(struct device
*dev
)
6717 #ifdef CONFIG_SCHED_SMT
6719 err
= device_create_file(dev
, &dev_attr_sched_smt_power_savings
);
6721 #ifdef CONFIG_SCHED_MC
6722 if (!err
&& mc_capable())
6723 err
= device_create_file(dev
, &dev_attr_sched_mc_power_savings
);
6727 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
6730 * Update cpusets according to cpu_active mask. If cpusets are
6731 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6732 * around partition_sched_domains().
6734 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6737 switch (action
& ~CPU_TASKS_FROZEN
) {
6739 case CPU_DOWN_FAILED
:
6740 cpuset_update_active_cpus();
6747 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6750 switch (action
& ~CPU_TASKS_FROZEN
) {
6751 case CPU_DOWN_PREPARE
:
6752 cpuset_update_active_cpus();
6759 void __init
sched_init_smp(void)
6761 cpumask_var_t non_isolated_cpus
;
6763 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6764 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6767 mutex_lock(&sched_domains_mutex
);
6768 init_sched_domains(cpu_active_mask
);
6769 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6770 if (cpumask_empty(non_isolated_cpus
))
6771 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6772 mutex_unlock(&sched_domains_mutex
);
6775 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6776 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6778 /* RT runtime code needs to handle some hotplug events */
6779 hotcpu_notifier(update_runtime
, 0);
6783 /* Move init over to a non-isolated CPU */
6784 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6786 sched_init_granularity();
6787 free_cpumask_var(non_isolated_cpus
);
6789 init_sched_rt_class();
6792 void __init
sched_init_smp(void)
6794 sched_init_granularity();
6796 #endif /* CONFIG_SMP */
6798 const_debug
unsigned int sysctl_timer_migration
= 1;
6800 int in_sched_functions(unsigned long addr
)
6802 return in_lock_functions(addr
) ||
6803 (addr
>= (unsigned long)__sched_text_start
6804 && addr
< (unsigned long)__sched_text_end
);
6807 #ifdef CONFIG_CGROUP_SCHED
6808 struct task_group root_task_group
;
6811 DECLARE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
6813 void __init
sched_init(void)
6816 unsigned long alloc_size
= 0, ptr
;
6818 #ifdef CONFIG_FAIR_GROUP_SCHED
6819 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6821 #ifdef CONFIG_RT_GROUP_SCHED
6822 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6824 #ifdef CONFIG_CPUMASK_OFFSTACK
6825 alloc_size
+= num_possible_cpus() * cpumask_size();
6828 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6830 #ifdef CONFIG_FAIR_GROUP_SCHED
6831 root_task_group
.se
= (struct sched_entity
**)ptr
;
6832 ptr
+= nr_cpu_ids
* sizeof(void **);
6834 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6835 ptr
+= nr_cpu_ids
* sizeof(void **);
6837 #endif /* CONFIG_FAIR_GROUP_SCHED */
6838 #ifdef CONFIG_RT_GROUP_SCHED
6839 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6840 ptr
+= nr_cpu_ids
* sizeof(void **);
6842 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6843 ptr
+= nr_cpu_ids
* sizeof(void **);
6845 #endif /* CONFIG_RT_GROUP_SCHED */
6846 #ifdef CONFIG_CPUMASK_OFFSTACK
6847 for_each_possible_cpu(i
) {
6848 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
6849 ptr
+= cpumask_size();
6851 #endif /* CONFIG_CPUMASK_OFFSTACK */
6855 init_defrootdomain();
6858 init_rt_bandwidth(&def_rt_bandwidth
,
6859 global_rt_period(), global_rt_runtime());
6861 #ifdef CONFIG_RT_GROUP_SCHED
6862 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6863 global_rt_period(), global_rt_runtime());
6864 #endif /* CONFIG_RT_GROUP_SCHED */
6866 #ifdef CONFIG_CGROUP_SCHED
6867 list_add(&root_task_group
.list
, &task_groups
);
6868 INIT_LIST_HEAD(&root_task_group
.children
);
6869 INIT_LIST_HEAD(&root_task_group
.siblings
);
6870 autogroup_init(&init_task
);
6872 #endif /* CONFIG_CGROUP_SCHED */
6874 #ifdef CONFIG_CGROUP_CPUACCT
6875 root_cpuacct
.cpustat
= &kernel_cpustat
;
6876 root_cpuacct
.cpuusage
= alloc_percpu(u64
);
6877 /* Too early, not expected to fail */
6878 BUG_ON(!root_cpuacct
.cpuusage
);
6880 for_each_possible_cpu(i
) {
6884 raw_spin_lock_init(&rq
->lock
);
6886 rq
->calc_load_active
= 0;
6887 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6888 init_cfs_rq(&rq
->cfs
);
6889 init_rt_rq(&rq
->rt
, rq
);
6890 #ifdef CONFIG_FAIR_GROUP_SCHED
6891 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6892 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6894 * How much cpu bandwidth does root_task_group get?
6896 * In case of task-groups formed thr' the cgroup filesystem, it
6897 * gets 100% of the cpu resources in the system. This overall
6898 * system cpu resource is divided among the tasks of
6899 * root_task_group and its child task-groups in a fair manner,
6900 * based on each entity's (task or task-group's) weight
6901 * (se->load.weight).
6903 * In other words, if root_task_group has 10 tasks of weight
6904 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6905 * then A0's share of the cpu resource is:
6907 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6909 * We achieve this by letting root_task_group's tasks sit
6910 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6912 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6913 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6914 #endif /* CONFIG_FAIR_GROUP_SCHED */
6916 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6917 #ifdef CONFIG_RT_GROUP_SCHED
6918 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
6919 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6922 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6923 rq
->cpu_load
[j
] = 0;
6925 rq
->last_load_update_tick
= jiffies
;
6930 rq
->cpu_power
= SCHED_POWER_SCALE
;
6931 rq
->post_schedule
= 0;
6932 rq
->active_balance
= 0;
6933 rq
->next_balance
= jiffies
;
6938 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
6939 rq_attach_root(rq
, &def_root_domain
);
6945 atomic_set(&rq
->nr_iowait
, 0);
6948 set_load_weight(&init_task
);
6950 #ifdef CONFIG_PREEMPT_NOTIFIERS
6951 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
6954 #ifdef CONFIG_RT_MUTEXES
6955 plist_head_init(&init_task
.pi_waiters
);
6959 * The boot idle thread does lazy MMU switching as well:
6961 atomic_inc(&init_mm
.mm_count
);
6962 enter_lazy_tlb(&init_mm
, current
);
6965 * Make us the idle thread. Technically, schedule() should not be
6966 * called from this thread, however somewhere below it might be,
6967 * but because we are the idle thread, we just pick up running again
6968 * when this runqueue becomes "idle".
6970 init_idle(current
, smp_processor_id());
6972 calc_load_update
= jiffies
+ LOAD_FREQ
;
6975 * During early bootup we pretend to be a normal task:
6977 current
->sched_class
= &fair_sched_class
;
6980 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
6981 /* May be allocated at isolcpus cmdline parse time */
6982 if (cpu_isolated_map
== NULL
)
6983 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
6985 init_sched_fair_class();
6987 scheduler_running
= 1;
6990 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6991 static inline int preempt_count_equals(int preempt_offset
)
6993 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
6995 return (nested
== preempt_offset
);
6998 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7000 static unsigned long prev_jiffy
; /* ratelimiting */
7002 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7003 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
7004 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7006 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7008 prev_jiffy
= jiffies
;
7011 "BUG: sleeping function called from invalid context at %s:%d\n",
7014 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7015 in_atomic(), irqs_disabled(),
7016 current
->pid
, current
->comm
);
7018 debug_show_held_locks(current
);
7019 if (irqs_disabled())
7020 print_irqtrace_events(current
);
7023 EXPORT_SYMBOL(__might_sleep
);
7026 #ifdef CONFIG_MAGIC_SYSRQ
7027 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7029 const struct sched_class
*prev_class
= p
->sched_class
;
7030 int old_prio
= p
->prio
;
7035 deactivate_task(rq
, p
, 0);
7036 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7038 activate_task(rq
, p
, 0);
7039 resched_task(rq
->curr
);
7042 check_class_changed(rq
, p
, prev_class
, old_prio
);
7045 void normalize_rt_tasks(void)
7047 struct task_struct
*g
, *p
;
7048 unsigned long flags
;
7051 read_lock_irqsave(&tasklist_lock
, flags
);
7052 do_each_thread(g
, p
) {
7054 * Only normalize user tasks:
7059 p
->se
.exec_start
= 0;
7060 #ifdef CONFIG_SCHEDSTATS
7061 p
->se
.statistics
.wait_start
= 0;
7062 p
->se
.statistics
.sleep_start
= 0;
7063 p
->se
.statistics
.block_start
= 0;
7068 * Renice negative nice level userspace
7071 if (TASK_NICE(p
) < 0 && p
->mm
)
7072 set_user_nice(p
, 0);
7076 raw_spin_lock(&p
->pi_lock
);
7077 rq
= __task_rq_lock(p
);
7079 normalize_task(rq
, p
);
7081 __task_rq_unlock(rq
);
7082 raw_spin_unlock(&p
->pi_lock
);
7083 } while_each_thread(g
, p
);
7085 read_unlock_irqrestore(&tasklist_lock
, flags
);
7088 #endif /* CONFIG_MAGIC_SYSRQ */
7090 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7092 * These functions are only useful for the IA64 MCA handling, or kdb.
7094 * They can only be called when the whole system has been
7095 * stopped - every CPU needs to be quiescent, and no scheduling
7096 * activity can take place. Using them for anything else would
7097 * be a serious bug, and as a result, they aren't even visible
7098 * under any other configuration.
7102 * curr_task - return the current task for a given cpu.
7103 * @cpu: the processor in question.
7105 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7107 struct task_struct
*curr_task(int cpu
)
7109 return cpu_curr(cpu
);
7112 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7116 * set_curr_task - set the current task for a given cpu.
7117 * @cpu: the processor in question.
7118 * @p: the task pointer to set.
7120 * Description: This function must only be used when non-maskable interrupts
7121 * are serviced on a separate stack. It allows the architecture to switch the
7122 * notion of the current task on a cpu in a non-blocking manner. This function
7123 * must be called with all CPU's synchronized, and interrupts disabled, the
7124 * and caller must save the original value of the current task (see
7125 * curr_task() above) and restore that value before reenabling interrupts and
7126 * re-starting the system.
7128 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7130 void set_curr_task(int cpu
, struct task_struct
*p
)
7137 #ifdef CONFIG_CGROUP_SCHED
7138 /* task_group_lock serializes the addition/removal of task groups */
7139 static DEFINE_SPINLOCK(task_group_lock
);
7141 static void free_sched_group(struct task_group
*tg
)
7143 free_fair_sched_group(tg
);
7144 free_rt_sched_group(tg
);
7149 /* allocate runqueue etc for a new task group */
7150 struct task_group
*sched_create_group(struct task_group
*parent
)
7152 struct task_group
*tg
;
7153 unsigned long flags
;
7155 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7157 return ERR_PTR(-ENOMEM
);
7159 if (!alloc_fair_sched_group(tg
, parent
))
7162 if (!alloc_rt_sched_group(tg
, parent
))
7165 spin_lock_irqsave(&task_group_lock
, flags
);
7166 list_add_rcu(&tg
->list
, &task_groups
);
7168 WARN_ON(!parent
); /* root should already exist */
7170 tg
->parent
= parent
;
7171 INIT_LIST_HEAD(&tg
->children
);
7172 list_add_rcu(&tg
->siblings
, &parent
->children
);
7173 spin_unlock_irqrestore(&task_group_lock
, flags
);
7178 free_sched_group(tg
);
7179 return ERR_PTR(-ENOMEM
);
7182 /* rcu callback to free various structures associated with a task group */
7183 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7185 /* now it should be safe to free those cfs_rqs */
7186 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7189 /* Destroy runqueue etc associated with a task group */
7190 void sched_destroy_group(struct task_group
*tg
)
7192 unsigned long flags
;
7195 /* end participation in shares distribution */
7196 for_each_possible_cpu(i
)
7197 unregister_fair_sched_group(tg
, i
);
7199 spin_lock_irqsave(&task_group_lock
, flags
);
7200 list_del_rcu(&tg
->list
);
7201 list_del_rcu(&tg
->siblings
);
7202 spin_unlock_irqrestore(&task_group_lock
, flags
);
7204 /* wait for possible concurrent references to cfs_rqs complete */
7205 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7208 /* change task's runqueue when it moves between groups.
7209 * The caller of this function should have put the task in its new group
7210 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7211 * reflect its new group.
7213 void sched_move_task(struct task_struct
*tsk
)
7216 unsigned long flags
;
7219 rq
= task_rq_lock(tsk
, &flags
);
7221 running
= task_current(rq
, tsk
);
7225 dequeue_task(rq
, tsk
, 0);
7226 if (unlikely(running
))
7227 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7229 #ifdef CONFIG_FAIR_GROUP_SCHED
7230 if (tsk
->sched_class
->task_move_group
)
7231 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
7234 set_task_rq(tsk
, task_cpu(tsk
));
7236 if (unlikely(running
))
7237 tsk
->sched_class
->set_curr_task(rq
);
7239 enqueue_task(rq
, tsk
, 0);
7241 task_rq_unlock(rq
, tsk
, &flags
);
7243 #endif /* CONFIG_CGROUP_SCHED */
7245 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
7246 static unsigned long to_ratio(u64 period
, u64 runtime
)
7248 if (runtime
== RUNTIME_INF
)
7251 return div64_u64(runtime
<< 20, period
);
7255 #ifdef CONFIG_RT_GROUP_SCHED
7257 * Ensure that the real time constraints are schedulable.
7259 static DEFINE_MUTEX(rt_constraints_mutex
);
7261 /* Must be called with tasklist_lock held */
7262 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7264 struct task_struct
*g
, *p
;
7266 do_each_thread(g
, p
) {
7267 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
7269 } while_each_thread(g
, p
);
7274 struct rt_schedulable_data
{
7275 struct task_group
*tg
;
7280 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7282 struct rt_schedulable_data
*d
= data
;
7283 struct task_group
*child
;
7284 unsigned long total
, sum
= 0;
7285 u64 period
, runtime
;
7287 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7288 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7291 period
= d
->rt_period
;
7292 runtime
= d
->rt_runtime
;
7296 * Cannot have more runtime than the period.
7298 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7302 * Ensure we don't starve existing RT tasks.
7304 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7307 total
= to_ratio(period
, runtime
);
7310 * Nobody can have more than the global setting allows.
7312 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7316 * The sum of our children's runtime should not exceed our own.
7318 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7319 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7320 runtime
= child
->rt_bandwidth
.rt_runtime
;
7322 if (child
== d
->tg
) {
7323 period
= d
->rt_period
;
7324 runtime
= d
->rt_runtime
;
7327 sum
+= to_ratio(period
, runtime
);
7336 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7340 struct rt_schedulable_data data
= {
7342 .rt_period
= period
,
7343 .rt_runtime
= runtime
,
7347 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7353 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7354 u64 rt_period
, u64 rt_runtime
)
7358 mutex_lock(&rt_constraints_mutex
);
7359 read_lock(&tasklist_lock
);
7360 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7364 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7365 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7366 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7368 for_each_possible_cpu(i
) {
7369 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7371 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7372 rt_rq
->rt_runtime
= rt_runtime
;
7373 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7375 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7377 read_unlock(&tasklist_lock
);
7378 mutex_unlock(&rt_constraints_mutex
);
7383 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7385 u64 rt_runtime
, rt_period
;
7387 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7388 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7389 if (rt_runtime_us
< 0)
7390 rt_runtime
= RUNTIME_INF
;
7392 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7395 long sched_group_rt_runtime(struct task_group
*tg
)
7399 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7402 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7403 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7404 return rt_runtime_us
;
7407 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7409 u64 rt_runtime
, rt_period
;
7411 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7412 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7417 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7420 long sched_group_rt_period(struct task_group
*tg
)
7424 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7425 do_div(rt_period_us
, NSEC_PER_USEC
);
7426 return rt_period_us
;
7429 static int sched_rt_global_constraints(void)
7431 u64 runtime
, period
;
7434 if (sysctl_sched_rt_period
<= 0)
7437 runtime
= global_rt_runtime();
7438 period
= global_rt_period();
7441 * Sanity check on the sysctl variables.
7443 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7446 mutex_lock(&rt_constraints_mutex
);
7447 read_lock(&tasklist_lock
);
7448 ret
= __rt_schedulable(NULL
, 0, 0);
7449 read_unlock(&tasklist_lock
);
7450 mutex_unlock(&rt_constraints_mutex
);
7455 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7457 /* Don't accept realtime tasks when there is no way for them to run */
7458 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7464 #else /* !CONFIG_RT_GROUP_SCHED */
7465 static int sched_rt_global_constraints(void)
7467 unsigned long flags
;
7470 if (sysctl_sched_rt_period
<= 0)
7474 * There's always some RT tasks in the root group
7475 * -- migration, kstopmachine etc..
7477 if (sysctl_sched_rt_runtime
== 0)
7480 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7481 for_each_possible_cpu(i
) {
7482 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7484 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7485 rt_rq
->rt_runtime
= global_rt_runtime();
7486 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7488 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7492 #endif /* CONFIG_RT_GROUP_SCHED */
7494 int sched_rt_handler(struct ctl_table
*table
, int write
,
7495 void __user
*buffer
, size_t *lenp
,
7499 int old_period
, old_runtime
;
7500 static DEFINE_MUTEX(mutex
);
7503 old_period
= sysctl_sched_rt_period
;
7504 old_runtime
= sysctl_sched_rt_runtime
;
7506 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7508 if (!ret
&& write
) {
7509 ret
= sched_rt_global_constraints();
7511 sysctl_sched_rt_period
= old_period
;
7512 sysctl_sched_rt_runtime
= old_runtime
;
7514 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7515 def_rt_bandwidth
.rt_period
=
7516 ns_to_ktime(global_rt_period());
7519 mutex_unlock(&mutex
);
7524 #ifdef CONFIG_CGROUP_SCHED
7526 /* return corresponding task_group object of a cgroup */
7527 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
7529 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
7530 struct task_group
, css
);
7533 static struct cgroup_subsys_state
*
7534 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
7536 struct task_group
*tg
, *parent
;
7538 if (!cgrp
->parent
) {
7539 /* This is early initialization for the top cgroup */
7540 return &root_task_group
.css
;
7543 parent
= cgroup_tg(cgrp
->parent
);
7544 tg
= sched_create_group(parent
);
7546 return ERR_PTR(-ENOMEM
);
7552 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
7554 struct task_group
*tg
= cgroup_tg(cgrp
);
7556 sched_destroy_group(tg
);
7559 static int cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
7560 struct cgroup_taskset
*tset
)
7562 struct task_struct
*task
;
7564 cgroup_taskset_for_each(task
, cgrp
, tset
) {
7565 #ifdef CONFIG_RT_GROUP_SCHED
7566 if (!sched_rt_can_attach(cgroup_tg(cgrp
), task
))
7569 /* We don't support RT-tasks being in separate groups */
7570 if (task
->sched_class
!= &fair_sched_class
)
7577 static void cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
7578 struct cgroup_taskset
*tset
)
7580 struct task_struct
*task
;
7582 cgroup_taskset_for_each(task
, cgrp
, tset
)
7583 sched_move_task(task
);
7587 cpu_cgroup_exit(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
7588 struct cgroup
*old_cgrp
, struct task_struct
*task
)
7591 * cgroup_exit() is called in the copy_process() failure path.
7592 * Ignore this case since the task hasn't ran yet, this avoids
7593 * trying to poke a half freed task state from generic code.
7595 if (!(task
->flags
& PF_EXITING
))
7598 sched_move_task(task
);
7601 #ifdef CONFIG_FAIR_GROUP_SCHED
7602 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7605 return sched_group_set_shares(cgroup_tg(cgrp
), scale_load(shareval
));
7608 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7610 struct task_group
*tg
= cgroup_tg(cgrp
);
7612 return (u64
) scale_load_down(tg
->shares
);
7615 #ifdef CONFIG_CFS_BANDWIDTH
7616 static DEFINE_MUTEX(cfs_constraints_mutex
);
7618 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7619 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7621 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7623 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7625 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7626 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7628 if (tg
== &root_task_group
)
7632 * Ensure we have at some amount of bandwidth every period. This is
7633 * to prevent reaching a state of large arrears when throttled via
7634 * entity_tick() resulting in prolonged exit starvation.
7636 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7640 * Likewise, bound things on the otherside by preventing insane quota
7641 * periods. This also allows us to normalize in computing quota
7644 if (period
> max_cfs_quota_period
)
7647 mutex_lock(&cfs_constraints_mutex
);
7648 ret
= __cfs_schedulable(tg
, period
, quota
);
7652 runtime_enabled
= quota
!= RUNTIME_INF
;
7653 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7654 account_cfs_bandwidth_used(runtime_enabled
, runtime_was_enabled
);
7655 raw_spin_lock_irq(&cfs_b
->lock
);
7656 cfs_b
->period
= ns_to_ktime(period
);
7657 cfs_b
->quota
= quota
;
7659 __refill_cfs_bandwidth_runtime(cfs_b
);
7660 /* restart the period timer (if active) to handle new period expiry */
7661 if (runtime_enabled
&& cfs_b
->timer_active
) {
7662 /* force a reprogram */
7663 cfs_b
->timer_active
= 0;
7664 __start_cfs_bandwidth(cfs_b
);
7666 raw_spin_unlock_irq(&cfs_b
->lock
);
7668 for_each_possible_cpu(i
) {
7669 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7670 struct rq
*rq
= cfs_rq
->rq
;
7672 raw_spin_lock_irq(&rq
->lock
);
7673 cfs_rq
->runtime_enabled
= runtime_enabled
;
7674 cfs_rq
->runtime_remaining
= 0;
7676 if (cfs_rq
->throttled
)
7677 unthrottle_cfs_rq(cfs_rq
);
7678 raw_spin_unlock_irq(&rq
->lock
);
7681 mutex_unlock(&cfs_constraints_mutex
);
7686 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7690 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7691 if (cfs_quota_us
< 0)
7692 quota
= RUNTIME_INF
;
7694 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7696 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7699 long tg_get_cfs_quota(struct task_group
*tg
)
7703 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7706 quota_us
= tg
->cfs_bandwidth
.quota
;
7707 do_div(quota_us
, NSEC_PER_USEC
);
7712 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7716 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7717 quota
= tg
->cfs_bandwidth
.quota
;
7719 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7722 long tg_get_cfs_period(struct task_group
*tg
)
7726 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7727 do_div(cfs_period_us
, NSEC_PER_USEC
);
7729 return cfs_period_us
;
7732 static s64
cpu_cfs_quota_read_s64(struct cgroup
*cgrp
, struct cftype
*cft
)
7734 return tg_get_cfs_quota(cgroup_tg(cgrp
));
7737 static int cpu_cfs_quota_write_s64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7740 return tg_set_cfs_quota(cgroup_tg(cgrp
), cfs_quota_us
);
7743 static u64
cpu_cfs_period_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
7745 return tg_get_cfs_period(cgroup_tg(cgrp
));
7748 static int cpu_cfs_period_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
7751 return tg_set_cfs_period(cgroup_tg(cgrp
), cfs_period_us
);
7754 struct cfs_schedulable_data
{
7755 struct task_group
*tg
;
7760 * normalize group quota/period to be quota/max_period
7761 * note: units are usecs
7763 static u64
normalize_cfs_quota(struct task_group
*tg
,
7764 struct cfs_schedulable_data
*d
)
7772 period
= tg_get_cfs_period(tg
);
7773 quota
= tg_get_cfs_quota(tg
);
7776 /* note: these should typically be equivalent */
7777 if (quota
== RUNTIME_INF
|| quota
== -1)
7780 return to_ratio(period
, quota
);
7783 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7785 struct cfs_schedulable_data
*d
= data
;
7786 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7787 s64 quota
= 0, parent_quota
= -1;
7790 quota
= RUNTIME_INF
;
7792 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
7794 quota
= normalize_cfs_quota(tg
, d
);
7795 parent_quota
= parent_b
->hierarchal_quota
;
7798 * ensure max(child_quota) <= parent_quota, inherit when no
7801 if (quota
== RUNTIME_INF
)
7802 quota
= parent_quota
;
7803 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
7806 cfs_b
->hierarchal_quota
= quota
;
7811 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
7814 struct cfs_schedulable_data data
= {
7820 if (quota
!= RUNTIME_INF
) {
7821 do_div(data
.period
, NSEC_PER_USEC
);
7822 do_div(data
.quota
, NSEC_PER_USEC
);
7826 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
7832 static int cpu_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
7833 struct cgroup_map_cb
*cb
)
7835 struct task_group
*tg
= cgroup_tg(cgrp
);
7836 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7838 cb
->fill(cb
, "nr_periods", cfs_b
->nr_periods
);
7839 cb
->fill(cb
, "nr_throttled", cfs_b
->nr_throttled
);
7840 cb
->fill(cb
, "throttled_time", cfs_b
->throttled_time
);
7844 #endif /* CONFIG_CFS_BANDWIDTH */
7845 #endif /* CONFIG_FAIR_GROUP_SCHED */
7847 #ifdef CONFIG_RT_GROUP_SCHED
7848 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
7851 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
7854 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
7856 return sched_group_rt_runtime(cgroup_tg(cgrp
));
7859 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
7862 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
7865 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
7867 return sched_group_rt_period(cgroup_tg(cgrp
));
7869 #endif /* CONFIG_RT_GROUP_SCHED */
7871 static struct cftype cpu_files
[] = {
7872 #ifdef CONFIG_FAIR_GROUP_SCHED
7875 .read_u64
= cpu_shares_read_u64
,
7876 .write_u64
= cpu_shares_write_u64
,
7879 #ifdef CONFIG_CFS_BANDWIDTH
7881 .name
= "cfs_quota_us",
7882 .read_s64
= cpu_cfs_quota_read_s64
,
7883 .write_s64
= cpu_cfs_quota_write_s64
,
7886 .name
= "cfs_period_us",
7887 .read_u64
= cpu_cfs_period_read_u64
,
7888 .write_u64
= cpu_cfs_period_write_u64
,
7892 .read_map
= cpu_stats_show
,
7895 #ifdef CONFIG_RT_GROUP_SCHED
7897 .name
= "rt_runtime_us",
7898 .read_s64
= cpu_rt_runtime_read
,
7899 .write_s64
= cpu_rt_runtime_write
,
7902 .name
= "rt_period_us",
7903 .read_u64
= cpu_rt_period_read_uint
,
7904 .write_u64
= cpu_rt_period_write_uint
,
7909 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
7911 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
7914 struct cgroup_subsys cpu_cgroup_subsys
= {
7916 .create
= cpu_cgroup_create
,
7917 .destroy
= cpu_cgroup_destroy
,
7918 .can_attach
= cpu_cgroup_can_attach
,
7919 .attach
= cpu_cgroup_attach
,
7920 .exit
= cpu_cgroup_exit
,
7921 .populate
= cpu_cgroup_populate
,
7922 .subsys_id
= cpu_cgroup_subsys_id
,
7926 #endif /* CONFIG_CGROUP_SCHED */
7928 #ifdef CONFIG_CGROUP_CPUACCT
7931 * CPU accounting code for task groups.
7933 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
7934 * (balbir@in.ibm.com).
7937 /* create a new cpu accounting group */
7938 static struct cgroup_subsys_state
*cpuacct_create(
7939 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
7944 return &root_cpuacct
.css
;
7946 ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
7950 ca
->cpuusage
= alloc_percpu(u64
);
7954 ca
->cpustat
= alloc_percpu(struct kernel_cpustat
);
7956 goto out_free_cpuusage
;
7961 free_percpu(ca
->cpuusage
);
7965 return ERR_PTR(-ENOMEM
);
7968 /* destroy an existing cpu accounting group */
7970 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
7972 struct cpuacct
*ca
= cgroup_ca(cgrp
);
7974 free_percpu(ca
->cpustat
);
7975 free_percpu(ca
->cpuusage
);
7979 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
7981 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
7984 #ifndef CONFIG_64BIT
7986 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
7988 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
7990 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
7998 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
8000 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8002 #ifndef CONFIG_64BIT
8004 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8006 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8008 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8014 /* return total cpu usage (in nanoseconds) of a group */
8015 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8017 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8018 u64 totalcpuusage
= 0;
8021 for_each_present_cpu(i
)
8022 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
8024 return totalcpuusage
;
8027 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8030 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8039 for_each_present_cpu(i
)
8040 cpuacct_cpuusage_write(ca
, i
, 0);
8046 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
8049 struct cpuacct
*ca
= cgroup_ca(cgroup
);
8053 for_each_present_cpu(i
) {
8054 percpu
= cpuacct_cpuusage_read(ca
, i
);
8055 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
8057 seq_printf(m
, "\n");
8061 static const char *cpuacct_stat_desc
[] = {
8062 [CPUACCT_STAT_USER
] = "user",
8063 [CPUACCT_STAT_SYSTEM
] = "system",
8066 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
8067 struct cgroup_map_cb
*cb
)
8069 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8073 for_each_online_cpu(cpu
) {
8074 struct kernel_cpustat
*kcpustat
= per_cpu_ptr(ca
->cpustat
, cpu
);
8075 val
+= kcpustat
->cpustat
[CPUTIME_USER
];
8076 val
+= kcpustat
->cpustat
[CPUTIME_NICE
];
8078 val
= cputime64_to_clock_t(val
);
8079 cb
->fill(cb
, cpuacct_stat_desc
[CPUACCT_STAT_USER
], val
);
8082 for_each_online_cpu(cpu
) {
8083 struct kernel_cpustat
*kcpustat
= per_cpu_ptr(ca
->cpustat
, cpu
);
8084 val
+= kcpustat
->cpustat
[CPUTIME_SYSTEM
];
8085 val
+= kcpustat
->cpustat
[CPUTIME_IRQ
];
8086 val
+= kcpustat
->cpustat
[CPUTIME_SOFTIRQ
];
8089 val
= cputime64_to_clock_t(val
);
8090 cb
->fill(cb
, cpuacct_stat_desc
[CPUACCT_STAT_SYSTEM
], val
);
8095 static struct cftype files
[] = {
8098 .read_u64
= cpuusage_read
,
8099 .write_u64
= cpuusage_write
,
8102 .name
= "usage_percpu",
8103 .read_seq_string
= cpuacct_percpu_seq_read
,
8107 .read_map
= cpuacct_stats_show
,
8111 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8113 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8117 * charge this task's execution time to its accounting group.
8119 * called with rq->lock held.
8121 void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8126 if (unlikely(!cpuacct_subsys
.active
))
8129 cpu
= task_cpu(tsk
);
8135 for (; ca
; ca
= parent_ca(ca
)) {
8136 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8137 *cpuusage
+= cputime
;
8143 struct cgroup_subsys cpuacct_subsys
= {
8145 .create
= cpuacct_create
,
8146 .destroy
= cpuacct_destroy
,
8147 .populate
= cpuacct_populate
,
8148 .subsys_id
= cpuacct_subsys_id
,
8150 #endif /* CONFIG_CGROUP_CPUACCT */