4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <asm/mmu_context.h>
36 #include <linux/interrupt.h>
37 #include <linux/capability.h>
38 #include <linux/completion.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/debug_locks.h>
41 #include <linux/perf_event.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/proc_fs.h>
58 #include <linux/seq_file.h>
59 #include <linux/sysctl.h>
60 #include <linux/syscalls.h>
61 #include <linux/times.h>
62 #include <linux/tsacct_kern.h>
63 #include <linux/kprobes.h>
64 #include <linux/delayacct.h>
65 #include <linux/unistd.h>
66 #include <linux/pagemap.h>
67 #include <linux/hrtimer.h>
68 #include <linux/tick.h>
69 #include <linux/debugfs.h>
70 #include <linux/ctype.h>
71 #include <linux/ftrace.h>
72 #include <linux/slab.h>
73 #include <linux/init_task.h>
74 #include <linux/binfmts.h>
75 #include <linux/context_tracking.h>
76 #include <linux/compiler.h>
78 #include <asm/switch_to.h>
80 #include <asm/irq_regs.h>
81 #include <asm/mutex.h>
82 #ifdef CONFIG_PARAVIRT
83 #include <asm/paravirt.h>
87 #include "../workqueue_internal.h"
88 #include "../smpboot.h"
90 #define CREATE_TRACE_POINTS
91 #include <trace/events/sched.h>
93 void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
96 ktime_t soft
, hard
, now
;
99 if (hrtimer_active(period_timer
))
102 now
= hrtimer_cb_get_time(period_timer
);
103 hrtimer_forward(period_timer
, now
, period
);
105 soft
= hrtimer_get_softexpires(period_timer
);
106 hard
= hrtimer_get_expires(period_timer
);
107 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
108 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
109 HRTIMER_MODE_ABS_PINNED
, 0);
113 DEFINE_MUTEX(sched_domains_mutex
);
114 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
116 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
118 void update_rq_clock(struct rq
*rq
)
122 if (rq
->skip_clock_update
> 0)
125 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
127 update_rq_clock_task(rq
, delta
);
131 * Debugging: various feature bits
134 #define SCHED_FEAT(name, enabled) \
135 (1UL << __SCHED_FEAT_##name) * enabled |
137 const_debug
unsigned int sysctl_sched_features
=
138 #include "features.h"
143 #ifdef CONFIG_SCHED_DEBUG
144 #define SCHED_FEAT(name, enabled) \
147 static const char * const sched_feat_names
[] = {
148 #include "features.h"
153 static int sched_feat_show(struct seq_file
*m
, void *v
)
157 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
158 if (!(sysctl_sched_features
& (1UL << i
)))
160 seq_printf(m
, "%s ", sched_feat_names
[i
]);
167 #ifdef HAVE_JUMP_LABEL
169 #define jump_label_key__true STATIC_KEY_INIT_TRUE
170 #define jump_label_key__false STATIC_KEY_INIT_FALSE
172 #define SCHED_FEAT(name, enabled) \
173 jump_label_key__##enabled ,
175 struct static_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
176 #include "features.h"
181 static void sched_feat_disable(int i
)
183 if (static_key_enabled(&sched_feat_keys
[i
]))
184 static_key_slow_dec(&sched_feat_keys
[i
]);
187 static void sched_feat_enable(int i
)
189 if (!static_key_enabled(&sched_feat_keys
[i
]))
190 static_key_slow_inc(&sched_feat_keys
[i
]);
193 static void sched_feat_disable(int i
) { };
194 static void sched_feat_enable(int i
) { };
195 #endif /* HAVE_JUMP_LABEL */
197 static int sched_feat_set(char *cmp
)
202 if (strncmp(cmp
, "NO_", 3) == 0) {
207 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
208 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
210 sysctl_sched_features
&= ~(1UL << i
);
211 sched_feat_disable(i
);
213 sysctl_sched_features
|= (1UL << i
);
214 sched_feat_enable(i
);
224 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
225 size_t cnt
, loff_t
*ppos
)
234 if (copy_from_user(&buf
, ubuf
, cnt
))
240 i
= sched_feat_set(cmp
);
241 if (i
== __SCHED_FEAT_NR
)
249 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
251 return single_open(filp
, sched_feat_show
, NULL
);
254 static const struct file_operations sched_feat_fops
= {
255 .open
= sched_feat_open
,
256 .write
= sched_feat_write
,
259 .release
= single_release
,
262 static __init
int sched_init_debug(void)
264 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
269 late_initcall(sched_init_debug
);
270 #endif /* CONFIG_SCHED_DEBUG */
273 * Number of tasks to iterate in a single balance run.
274 * Limited because this is done with IRQs disabled.
276 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
279 * period over which we average the RT time consumption, measured
284 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
287 * period over which we measure -rt task cpu usage in us.
290 unsigned int sysctl_sched_rt_period
= 1000000;
292 __read_mostly
int scheduler_running
;
295 * part of the period that we allow rt tasks to run in us.
298 int sysctl_sched_rt_runtime
= 950000;
301 * __task_rq_lock - lock the rq @p resides on.
303 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
308 lockdep_assert_held(&p
->pi_lock
);
312 raw_spin_lock(&rq
->lock
);
313 if (likely(rq
== task_rq(p
)))
315 raw_spin_unlock(&rq
->lock
);
320 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
322 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
323 __acquires(p
->pi_lock
)
329 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
331 raw_spin_lock(&rq
->lock
);
332 if (likely(rq
== task_rq(p
)))
334 raw_spin_unlock(&rq
->lock
);
335 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
339 static void __task_rq_unlock(struct rq
*rq
)
342 raw_spin_unlock(&rq
->lock
);
346 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
348 __releases(p
->pi_lock
)
350 raw_spin_unlock(&rq
->lock
);
351 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
355 * this_rq_lock - lock this runqueue and disable interrupts.
357 static struct rq
*this_rq_lock(void)
364 raw_spin_lock(&rq
->lock
);
369 #ifdef CONFIG_SCHED_HRTICK
371 * Use HR-timers to deliver accurate preemption points.
374 static void hrtick_clear(struct rq
*rq
)
376 if (hrtimer_active(&rq
->hrtick_timer
))
377 hrtimer_cancel(&rq
->hrtick_timer
);
381 * High-resolution timer tick.
382 * Runs from hardirq context with interrupts disabled.
384 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
386 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
388 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
390 raw_spin_lock(&rq
->lock
);
392 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
393 raw_spin_unlock(&rq
->lock
);
395 return HRTIMER_NORESTART
;
400 static int __hrtick_restart(struct rq
*rq
)
402 struct hrtimer
*timer
= &rq
->hrtick_timer
;
403 ktime_t time
= hrtimer_get_softexpires(timer
);
405 return __hrtimer_start_range_ns(timer
, time
, 0, HRTIMER_MODE_ABS_PINNED
, 0);
409 * called from hardirq (IPI) context
411 static void __hrtick_start(void *arg
)
415 raw_spin_lock(&rq
->lock
);
416 __hrtick_restart(rq
);
417 rq
->hrtick_csd_pending
= 0;
418 raw_spin_unlock(&rq
->lock
);
422 * Called to set the hrtick timer state.
424 * called with rq->lock held and irqs disabled
426 void hrtick_start(struct rq
*rq
, u64 delay
)
428 struct hrtimer
*timer
= &rq
->hrtick_timer
;
429 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
431 hrtimer_set_expires(timer
, time
);
433 if (rq
== this_rq()) {
434 __hrtick_restart(rq
);
435 } else if (!rq
->hrtick_csd_pending
) {
436 smp_call_function_single_async(cpu_of(rq
), &rq
->hrtick_csd
);
437 rq
->hrtick_csd_pending
= 1;
442 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
444 int cpu
= (int)(long)hcpu
;
447 case CPU_UP_CANCELED
:
448 case CPU_UP_CANCELED_FROZEN
:
449 case CPU_DOWN_PREPARE
:
450 case CPU_DOWN_PREPARE_FROZEN
:
452 case CPU_DEAD_FROZEN
:
453 hrtick_clear(cpu_rq(cpu
));
460 static __init
void init_hrtick(void)
462 hotcpu_notifier(hotplug_hrtick
, 0);
466 * Called to set the hrtick timer state.
468 * called with rq->lock held and irqs disabled
470 void hrtick_start(struct rq
*rq
, u64 delay
)
472 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
473 HRTIMER_MODE_REL_PINNED
, 0);
476 static inline void init_hrtick(void)
479 #endif /* CONFIG_SMP */
481 static void init_rq_hrtick(struct rq
*rq
)
484 rq
->hrtick_csd_pending
= 0;
486 rq
->hrtick_csd
.flags
= 0;
487 rq
->hrtick_csd
.func
= __hrtick_start
;
488 rq
->hrtick_csd
.info
= rq
;
491 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
492 rq
->hrtick_timer
.function
= hrtick
;
494 #else /* CONFIG_SCHED_HRTICK */
495 static inline void hrtick_clear(struct rq
*rq
)
499 static inline void init_rq_hrtick(struct rq
*rq
)
503 static inline void init_hrtick(void)
506 #endif /* CONFIG_SCHED_HRTICK */
509 * cmpxchg based fetch_or, macro so it works for different integer types
511 #define fetch_or(ptr, val) \
512 ({ typeof(*(ptr)) __old, __val = *(ptr); \
514 __old = cmpxchg((ptr), __val, __val | (val)); \
515 if (__old == __val) \
522 #ifdef TIF_POLLING_NRFLAG
524 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
525 * this avoids any races wrt polling state changes and thereby avoids
528 static bool set_nr_and_not_polling(struct task_struct
*p
)
530 struct thread_info
*ti
= task_thread_info(p
);
531 return !(fetch_or(&ti
->flags
, _TIF_NEED_RESCHED
) & _TIF_POLLING_NRFLAG
);
534 static bool set_nr_and_not_polling(struct task_struct
*p
)
536 set_tsk_need_resched(p
);
542 * resched_task - mark a task 'to be rescheduled now'.
544 * On UP this means the setting of the need_resched flag, on SMP it
545 * might also involve a cross-CPU call to trigger the scheduler on
548 void resched_task(struct task_struct
*p
)
552 lockdep_assert_held(&task_rq(p
)->lock
);
554 if (test_tsk_need_resched(p
))
559 if (cpu
== smp_processor_id()) {
560 set_tsk_need_resched(p
);
561 set_preempt_need_resched();
565 if (set_nr_and_not_polling(p
))
566 smp_send_reschedule(cpu
);
569 void resched_cpu(int cpu
)
571 struct rq
*rq
= cpu_rq(cpu
);
574 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
576 resched_task(cpu_curr(cpu
));
577 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
581 #ifdef CONFIG_NO_HZ_COMMON
583 * In the semi idle case, use the nearest busy cpu for migrating timers
584 * from an idle cpu. This is good for power-savings.
586 * We don't do similar optimization for completely idle system, as
587 * selecting an idle cpu will add more delays to the timers than intended
588 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
590 int get_nohz_timer_target(int pinned
)
592 int cpu
= smp_processor_id();
594 struct sched_domain
*sd
;
596 if (pinned
|| !get_sysctl_timer_migration() || !idle_cpu(cpu
))
600 for_each_domain(cpu
, sd
) {
601 for_each_cpu(i
, sched_domain_span(sd
)) {
613 * When add_timer_on() enqueues a timer into the timer wheel of an
614 * idle CPU then this timer might expire before the next timer event
615 * which is scheduled to wake up that CPU. In case of a completely
616 * idle system the next event might even be infinite time into the
617 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
618 * leaves the inner idle loop so the newly added timer is taken into
619 * account when the CPU goes back to idle and evaluates the timer
620 * wheel for the next timer event.
622 static void wake_up_idle_cpu(int cpu
)
624 struct rq
*rq
= cpu_rq(cpu
);
626 if (cpu
== smp_processor_id())
630 * This is safe, as this function is called with the timer
631 * wheel base lock of (cpu) held. When the CPU is on the way
632 * to idle and has not yet set rq->curr to idle then it will
633 * be serialized on the timer wheel base lock and take the new
634 * timer into account automatically.
636 if (rq
->curr
!= rq
->idle
)
640 * We can set TIF_RESCHED on the idle task of the other CPU
641 * lockless. The worst case is that the other CPU runs the
642 * idle task through an additional NOOP schedule()
644 set_tsk_need_resched(rq
->idle
);
646 /* NEED_RESCHED must be visible before we test polling */
648 if (!tsk_is_polling(rq
->idle
))
649 smp_send_reschedule(cpu
);
652 static bool wake_up_full_nohz_cpu(int cpu
)
654 if (tick_nohz_full_cpu(cpu
)) {
655 if (cpu
!= smp_processor_id() ||
656 tick_nohz_tick_stopped())
657 smp_send_reschedule(cpu
);
664 void wake_up_nohz_cpu(int cpu
)
666 if (!wake_up_full_nohz_cpu(cpu
))
667 wake_up_idle_cpu(cpu
);
670 static inline bool got_nohz_idle_kick(void)
672 int cpu
= smp_processor_id();
674 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
677 if (idle_cpu(cpu
) && !need_resched())
681 * We can't run Idle Load Balance on this CPU for this time so we
682 * cancel it and clear NOHZ_BALANCE_KICK
684 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
688 #else /* CONFIG_NO_HZ_COMMON */
690 static inline bool got_nohz_idle_kick(void)
695 #endif /* CONFIG_NO_HZ_COMMON */
697 #ifdef CONFIG_NO_HZ_FULL
698 bool sched_can_stop_tick(void)
704 /* Make sure rq->nr_running update is visible after the IPI */
707 /* More than one running task need preemption */
708 if (rq
->nr_running
> 1)
713 #endif /* CONFIG_NO_HZ_FULL */
715 void sched_avg_update(struct rq
*rq
)
717 s64 period
= sched_avg_period();
719 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
721 * Inline assembly required to prevent the compiler
722 * optimising this loop into a divmod call.
723 * See __iter_div_u64_rem() for another example of this.
725 asm("" : "+rm" (rq
->age_stamp
));
726 rq
->age_stamp
+= period
;
731 #endif /* CONFIG_SMP */
733 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
734 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
736 * Iterate task_group tree rooted at *from, calling @down when first entering a
737 * node and @up when leaving it for the final time.
739 * Caller must hold rcu_lock or sufficient equivalent.
741 int walk_tg_tree_from(struct task_group
*from
,
742 tg_visitor down
, tg_visitor up
, void *data
)
744 struct task_group
*parent
, *child
;
750 ret
= (*down
)(parent
, data
);
753 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
760 ret
= (*up
)(parent
, data
);
761 if (ret
|| parent
== from
)
765 parent
= parent
->parent
;
772 int tg_nop(struct task_group
*tg
, void *data
)
778 static void set_load_weight(struct task_struct
*p
)
780 int prio
= p
->static_prio
- MAX_RT_PRIO
;
781 struct load_weight
*load
= &p
->se
.load
;
784 * SCHED_IDLE tasks get minimal weight:
786 if (p
->policy
== SCHED_IDLE
) {
787 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
788 load
->inv_weight
= WMULT_IDLEPRIO
;
792 load
->weight
= scale_load(prio_to_weight
[prio
]);
793 load
->inv_weight
= prio_to_wmult
[prio
];
796 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
799 sched_info_queued(rq
, p
);
800 p
->sched_class
->enqueue_task(rq
, p
, flags
);
803 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
806 sched_info_dequeued(rq
, p
);
807 p
->sched_class
->dequeue_task(rq
, p
, flags
);
810 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
812 if (task_contributes_to_load(p
))
813 rq
->nr_uninterruptible
--;
815 enqueue_task(rq
, p
, flags
);
818 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
820 if (task_contributes_to_load(p
))
821 rq
->nr_uninterruptible
++;
823 dequeue_task(rq
, p
, flags
);
826 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
829 * In theory, the compile should just see 0 here, and optimize out the call
830 * to sched_rt_avg_update. But I don't trust it...
832 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
833 s64 steal
= 0, irq_delta
= 0;
835 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
836 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
839 * Since irq_time is only updated on {soft,}irq_exit, we might run into
840 * this case when a previous update_rq_clock() happened inside a
843 * When this happens, we stop ->clock_task and only update the
844 * prev_irq_time stamp to account for the part that fit, so that a next
845 * update will consume the rest. This ensures ->clock_task is
848 * It does however cause some slight miss-attribution of {soft,}irq
849 * time, a more accurate solution would be to update the irq_time using
850 * the current rq->clock timestamp, except that would require using
853 if (irq_delta
> delta
)
856 rq
->prev_irq_time
+= irq_delta
;
859 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
860 if (static_key_false((¶virt_steal_rq_enabled
))) {
861 steal
= paravirt_steal_clock(cpu_of(rq
));
862 steal
-= rq
->prev_steal_time_rq
;
864 if (unlikely(steal
> delta
))
867 rq
->prev_steal_time_rq
+= steal
;
872 rq
->clock_task
+= delta
;
874 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
875 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
876 sched_rt_avg_update(rq
, irq_delta
+ steal
);
880 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
882 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
883 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
887 * Make it appear like a SCHED_FIFO task, its something
888 * userspace knows about and won't get confused about.
890 * Also, it will make PI more or less work without too
891 * much confusion -- but then, stop work should not
892 * rely on PI working anyway.
894 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
896 stop
->sched_class
= &stop_sched_class
;
899 cpu_rq(cpu
)->stop
= stop
;
903 * Reset it back to a normal scheduling class so that
904 * it can die in pieces.
906 old_stop
->sched_class
= &rt_sched_class
;
911 * __normal_prio - return the priority that is based on the static prio
913 static inline int __normal_prio(struct task_struct
*p
)
915 return p
->static_prio
;
919 * Calculate the expected normal priority: i.e. priority
920 * without taking RT-inheritance into account. Might be
921 * boosted by interactivity modifiers. Changes upon fork,
922 * setprio syscalls, and whenever the interactivity
923 * estimator recalculates.
925 static inline int normal_prio(struct task_struct
*p
)
929 if (task_has_dl_policy(p
))
930 prio
= MAX_DL_PRIO
-1;
931 else if (task_has_rt_policy(p
))
932 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
934 prio
= __normal_prio(p
);
939 * Calculate the current priority, i.e. the priority
940 * taken into account by the scheduler. This value might
941 * be boosted by RT tasks, or might be boosted by
942 * interactivity modifiers. Will be RT if the task got
943 * RT-boosted. If not then it returns p->normal_prio.
945 static int effective_prio(struct task_struct
*p
)
947 p
->normal_prio
= normal_prio(p
);
949 * If we are RT tasks or we were boosted to RT priority,
950 * keep the priority unchanged. Otherwise, update priority
951 * to the normal priority:
953 if (!rt_prio(p
->prio
))
954 return p
->normal_prio
;
959 * task_curr - is this task currently executing on a CPU?
960 * @p: the task in question.
962 * Return: 1 if the task is currently executing. 0 otherwise.
964 inline int task_curr(const struct task_struct
*p
)
966 return cpu_curr(task_cpu(p
)) == p
;
969 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
970 const struct sched_class
*prev_class
,
973 if (prev_class
!= p
->sched_class
) {
974 if (prev_class
->switched_from
)
975 prev_class
->switched_from(rq
, p
);
976 p
->sched_class
->switched_to(rq
, p
);
977 } else if (oldprio
!= p
->prio
|| dl_task(p
))
978 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
981 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
983 const struct sched_class
*class;
985 if (p
->sched_class
== rq
->curr
->sched_class
) {
986 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
988 for_each_class(class) {
989 if (class == rq
->curr
->sched_class
)
991 if (class == p
->sched_class
) {
992 resched_task(rq
->curr
);
999 * A queue event has occurred, and we're going to schedule. In
1000 * this case, we can save a useless back to back clock update.
1002 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
1003 rq
->skip_clock_update
= 1;
1007 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1009 #ifdef CONFIG_SCHED_DEBUG
1011 * We should never call set_task_cpu() on a blocked task,
1012 * ttwu() will sort out the placement.
1014 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
1015 !(task_preempt_count(p
) & PREEMPT_ACTIVE
));
1017 #ifdef CONFIG_LOCKDEP
1019 * The caller should hold either p->pi_lock or rq->lock, when changing
1020 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1022 * sched_move_task() holds both and thus holding either pins the cgroup,
1025 * Furthermore, all task_rq users should acquire both locks, see
1028 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1029 lockdep_is_held(&task_rq(p
)->lock
)));
1033 trace_sched_migrate_task(p
, new_cpu
);
1035 if (task_cpu(p
) != new_cpu
) {
1036 if (p
->sched_class
->migrate_task_rq
)
1037 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1038 p
->se
.nr_migrations
++;
1039 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1042 __set_task_cpu(p
, new_cpu
);
1045 static void __migrate_swap_task(struct task_struct
*p
, int cpu
)
1048 struct rq
*src_rq
, *dst_rq
;
1050 src_rq
= task_rq(p
);
1051 dst_rq
= cpu_rq(cpu
);
1053 deactivate_task(src_rq
, p
, 0);
1054 set_task_cpu(p
, cpu
);
1055 activate_task(dst_rq
, p
, 0);
1056 check_preempt_curr(dst_rq
, p
, 0);
1059 * Task isn't running anymore; make it appear like we migrated
1060 * it before it went to sleep. This means on wakeup we make the
1061 * previous cpu our targer instead of where it really is.
1067 struct migration_swap_arg
{
1068 struct task_struct
*src_task
, *dst_task
;
1069 int src_cpu
, dst_cpu
;
1072 static int migrate_swap_stop(void *data
)
1074 struct migration_swap_arg
*arg
= data
;
1075 struct rq
*src_rq
, *dst_rq
;
1078 src_rq
= cpu_rq(arg
->src_cpu
);
1079 dst_rq
= cpu_rq(arg
->dst_cpu
);
1081 double_raw_lock(&arg
->src_task
->pi_lock
,
1082 &arg
->dst_task
->pi_lock
);
1083 double_rq_lock(src_rq
, dst_rq
);
1084 if (task_cpu(arg
->dst_task
) != arg
->dst_cpu
)
1087 if (task_cpu(arg
->src_task
) != arg
->src_cpu
)
1090 if (!cpumask_test_cpu(arg
->dst_cpu
, tsk_cpus_allowed(arg
->src_task
)))
1093 if (!cpumask_test_cpu(arg
->src_cpu
, tsk_cpus_allowed(arg
->dst_task
)))
1096 __migrate_swap_task(arg
->src_task
, arg
->dst_cpu
);
1097 __migrate_swap_task(arg
->dst_task
, arg
->src_cpu
);
1102 double_rq_unlock(src_rq
, dst_rq
);
1103 raw_spin_unlock(&arg
->dst_task
->pi_lock
);
1104 raw_spin_unlock(&arg
->src_task
->pi_lock
);
1110 * Cross migrate two tasks
1112 int migrate_swap(struct task_struct
*cur
, struct task_struct
*p
)
1114 struct migration_swap_arg arg
;
1117 arg
= (struct migration_swap_arg
){
1119 .src_cpu
= task_cpu(cur
),
1121 .dst_cpu
= task_cpu(p
),
1124 if (arg
.src_cpu
== arg
.dst_cpu
)
1128 * These three tests are all lockless; this is OK since all of them
1129 * will be re-checked with proper locks held further down the line.
1131 if (!cpu_active(arg
.src_cpu
) || !cpu_active(arg
.dst_cpu
))
1134 if (!cpumask_test_cpu(arg
.dst_cpu
, tsk_cpus_allowed(arg
.src_task
)))
1137 if (!cpumask_test_cpu(arg
.src_cpu
, tsk_cpus_allowed(arg
.dst_task
)))
1140 trace_sched_swap_numa(cur
, arg
.src_cpu
, p
, arg
.dst_cpu
);
1141 ret
= stop_two_cpus(arg
.dst_cpu
, arg
.src_cpu
, migrate_swap_stop
, &arg
);
1147 struct migration_arg
{
1148 struct task_struct
*task
;
1152 static int migration_cpu_stop(void *data
);
1155 * wait_task_inactive - wait for a thread to unschedule.
1157 * If @match_state is nonzero, it's the @p->state value just checked and
1158 * not expected to change. If it changes, i.e. @p might have woken up,
1159 * then return zero. When we succeed in waiting for @p to be off its CPU,
1160 * we return a positive number (its total switch count). If a second call
1161 * a short while later returns the same number, the caller can be sure that
1162 * @p has remained unscheduled the whole time.
1164 * The caller must ensure that the task *will* unschedule sometime soon,
1165 * else this function might spin for a *long* time. This function can't
1166 * be called with interrupts off, or it may introduce deadlock with
1167 * smp_call_function() if an IPI is sent by the same process we are
1168 * waiting to become inactive.
1170 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1172 unsigned long flags
;
1179 * We do the initial early heuristics without holding
1180 * any task-queue locks at all. We'll only try to get
1181 * the runqueue lock when things look like they will
1187 * If the task is actively running on another CPU
1188 * still, just relax and busy-wait without holding
1191 * NOTE! Since we don't hold any locks, it's not
1192 * even sure that "rq" stays as the right runqueue!
1193 * But we don't care, since "task_running()" will
1194 * return false if the runqueue has changed and p
1195 * is actually now running somewhere else!
1197 while (task_running(rq
, p
)) {
1198 if (match_state
&& unlikely(p
->state
!= match_state
))
1204 * Ok, time to look more closely! We need the rq
1205 * lock now, to be *sure*. If we're wrong, we'll
1206 * just go back and repeat.
1208 rq
= task_rq_lock(p
, &flags
);
1209 trace_sched_wait_task(p
);
1210 running
= task_running(rq
, p
);
1213 if (!match_state
|| p
->state
== match_state
)
1214 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1215 task_rq_unlock(rq
, p
, &flags
);
1218 * If it changed from the expected state, bail out now.
1220 if (unlikely(!ncsw
))
1224 * Was it really running after all now that we
1225 * checked with the proper locks actually held?
1227 * Oops. Go back and try again..
1229 if (unlikely(running
)) {
1235 * It's not enough that it's not actively running,
1236 * it must be off the runqueue _entirely_, and not
1239 * So if it was still runnable (but just not actively
1240 * running right now), it's preempted, and we should
1241 * yield - it could be a while.
1243 if (unlikely(on_rq
)) {
1244 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1246 set_current_state(TASK_UNINTERRUPTIBLE
);
1247 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1252 * Ahh, all good. It wasn't running, and it wasn't
1253 * runnable, which means that it will never become
1254 * running in the future either. We're all done!
1263 * kick_process - kick a running thread to enter/exit the kernel
1264 * @p: the to-be-kicked thread
1266 * Cause a process which is running on another CPU to enter
1267 * kernel-mode, without any delay. (to get signals handled.)
1269 * NOTE: this function doesn't have to take the runqueue lock,
1270 * because all it wants to ensure is that the remote task enters
1271 * the kernel. If the IPI races and the task has been migrated
1272 * to another CPU then no harm is done and the purpose has been
1275 void kick_process(struct task_struct
*p
)
1281 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1282 smp_send_reschedule(cpu
);
1285 EXPORT_SYMBOL_GPL(kick_process
);
1286 #endif /* CONFIG_SMP */
1290 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1292 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1294 int nid
= cpu_to_node(cpu
);
1295 const struct cpumask
*nodemask
= NULL
;
1296 enum { cpuset
, possible
, fail
} state
= cpuset
;
1300 * If the node that the cpu is on has been offlined, cpu_to_node()
1301 * will return -1. There is no cpu on the node, and we should
1302 * select the cpu on the other node.
1305 nodemask
= cpumask_of_node(nid
);
1307 /* Look for allowed, online CPU in same node. */
1308 for_each_cpu(dest_cpu
, nodemask
) {
1309 if (!cpu_online(dest_cpu
))
1311 if (!cpu_active(dest_cpu
))
1313 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1319 /* Any allowed, online CPU? */
1320 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1321 if (!cpu_online(dest_cpu
))
1323 if (!cpu_active(dest_cpu
))
1330 /* No more Mr. Nice Guy. */
1331 cpuset_cpus_allowed_fallback(p
);
1336 do_set_cpus_allowed(p
, cpu_possible_mask
);
1347 if (state
!= cpuset
) {
1349 * Don't tell them about moving exiting tasks or
1350 * kernel threads (both mm NULL), since they never
1353 if (p
->mm
&& printk_ratelimit()) {
1354 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1355 task_pid_nr(p
), p
->comm
, cpu
);
1363 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1366 int select_task_rq(struct task_struct
*p
, int cpu
, int sd_flags
, int wake_flags
)
1368 cpu
= p
->sched_class
->select_task_rq(p
, cpu
, sd_flags
, wake_flags
);
1371 * In order not to call set_task_cpu() on a blocking task we need
1372 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1375 * Since this is common to all placement strategies, this lives here.
1377 * [ this allows ->select_task() to simply return task_cpu(p) and
1378 * not worry about this generic constraint ]
1380 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1382 cpu
= select_fallback_rq(task_cpu(p
), p
);
1387 static void update_avg(u64
*avg
, u64 sample
)
1389 s64 diff
= sample
- *avg
;
1395 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1397 #ifdef CONFIG_SCHEDSTATS
1398 struct rq
*rq
= this_rq();
1401 int this_cpu
= smp_processor_id();
1403 if (cpu
== this_cpu
) {
1404 schedstat_inc(rq
, ttwu_local
);
1405 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1407 struct sched_domain
*sd
;
1409 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1411 for_each_domain(this_cpu
, sd
) {
1412 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1413 schedstat_inc(sd
, ttwu_wake_remote
);
1420 if (wake_flags
& WF_MIGRATED
)
1421 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1423 #endif /* CONFIG_SMP */
1425 schedstat_inc(rq
, ttwu_count
);
1426 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1428 if (wake_flags
& WF_SYNC
)
1429 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1431 #endif /* CONFIG_SCHEDSTATS */
1434 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1436 activate_task(rq
, p
, en_flags
);
1439 /* if a worker is waking up, notify workqueue */
1440 if (p
->flags
& PF_WQ_WORKER
)
1441 wq_worker_waking_up(p
, cpu_of(rq
));
1445 * Mark the task runnable and perform wakeup-preemption.
1448 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1450 check_preempt_curr(rq
, p
, wake_flags
);
1451 trace_sched_wakeup(p
, true);
1453 p
->state
= TASK_RUNNING
;
1455 if (p
->sched_class
->task_woken
)
1456 p
->sched_class
->task_woken(rq
, p
);
1458 if (rq
->idle_stamp
) {
1459 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1460 u64 max
= 2*rq
->max_idle_balance_cost
;
1462 update_avg(&rq
->avg_idle
, delta
);
1464 if (rq
->avg_idle
> max
)
1473 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1476 if (p
->sched_contributes_to_load
)
1477 rq
->nr_uninterruptible
--;
1480 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1481 ttwu_do_wakeup(rq
, p
, wake_flags
);
1485 * Called in case the task @p isn't fully descheduled from its runqueue,
1486 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1487 * since all we need to do is flip p->state to TASK_RUNNING, since
1488 * the task is still ->on_rq.
1490 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1495 rq
= __task_rq_lock(p
);
1497 /* check_preempt_curr() may use rq clock */
1498 update_rq_clock(rq
);
1499 ttwu_do_wakeup(rq
, p
, wake_flags
);
1502 __task_rq_unlock(rq
);
1508 static void sched_ttwu_pending(void)
1510 struct rq
*rq
= this_rq();
1511 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1512 struct task_struct
*p
;
1514 raw_spin_lock(&rq
->lock
);
1517 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1518 llist
= llist_next(llist
);
1519 ttwu_do_activate(rq
, p
, 0);
1522 raw_spin_unlock(&rq
->lock
);
1525 void scheduler_ipi(void)
1528 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1529 * TIF_NEED_RESCHED remotely (for the first time) will also send
1532 preempt_fold_need_resched();
1534 if (llist_empty(&this_rq()->wake_list
)
1535 && !tick_nohz_full_cpu(smp_processor_id())
1536 && !got_nohz_idle_kick())
1540 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1541 * traditionally all their work was done from the interrupt return
1542 * path. Now that we actually do some work, we need to make sure
1545 * Some archs already do call them, luckily irq_enter/exit nest
1548 * Arguably we should visit all archs and update all handlers,
1549 * however a fair share of IPIs are still resched only so this would
1550 * somewhat pessimize the simple resched case.
1553 tick_nohz_full_check();
1554 sched_ttwu_pending();
1557 * Check if someone kicked us for doing the nohz idle load balance.
1559 if (unlikely(got_nohz_idle_kick())) {
1560 this_rq()->idle_balance
= 1;
1561 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1566 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1568 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
1569 smp_send_reschedule(cpu
);
1572 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1574 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1576 #endif /* CONFIG_SMP */
1578 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1580 struct rq
*rq
= cpu_rq(cpu
);
1582 #if defined(CONFIG_SMP)
1583 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1584 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1585 ttwu_queue_remote(p
, cpu
);
1590 raw_spin_lock(&rq
->lock
);
1591 ttwu_do_activate(rq
, p
, 0);
1592 raw_spin_unlock(&rq
->lock
);
1596 * try_to_wake_up - wake up a thread
1597 * @p: the thread to be awakened
1598 * @state: the mask of task states that can be woken
1599 * @wake_flags: wake modifier flags (WF_*)
1601 * Put it on the run-queue if it's not already there. The "current"
1602 * thread is always on the run-queue (except when the actual
1603 * re-schedule is in progress), and as such you're allowed to do
1604 * the simpler "current->state = TASK_RUNNING" to mark yourself
1605 * runnable without the overhead of this.
1607 * Return: %true if @p was woken up, %false if it was already running.
1608 * or @state didn't match @p's state.
1611 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1613 unsigned long flags
;
1614 int cpu
, success
= 0;
1617 * If we are going to wake up a thread waiting for CONDITION we
1618 * need to ensure that CONDITION=1 done by the caller can not be
1619 * reordered with p->state check below. This pairs with mb() in
1620 * set_current_state() the waiting thread does.
1622 smp_mb__before_spinlock();
1623 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1624 if (!(p
->state
& state
))
1627 success
= 1; /* we're going to change ->state */
1630 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1635 * If the owning (remote) cpu is still in the middle of schedule() with
1636 * this task as prev, wait until its done referencing the task.
1641 * Pairs with the smp_wmb() in finish_lock_switch().
1645 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1646 p
->state
= TASK_WAKING
;
1648 if (p
->sched_class
->task_waking
)
1649 p
->sched_class
->task_waking(p
);
1651 cpu
= select_task_rq(p
, p
->wake_cpu
, SD_BALANCE_WAKE
, wake_flags
);
1652 if (task_cpu(p
) != cpu
) {
1653 wake_flags
|= WF_MIGRATED
;
1654 set_task_cpu(p
, cpu
);
1656 #endif /* CONFIG_SMP */
1660 ttwu_stat(p
, cpu
, wake_flags
);
1662 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1668 * try_to_wake_up_local - try to wake up a local task with rq lock held
1669 * @p: the thread to be awakened
1671 * Put @p on the run-queue if it's not already there. The caller must
1672 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1675 static void try_to_wake_up_local(struct task_struct
*p
)
1677 struct rq
*rq
= task_rq(p
);
1679 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1680 WARN_ON_ONCE(p
== current
))
1683 lockdep_assert_held(&rq
->lock
);
1685 if (!raw_spin_trylock(&p
->pi_lock
)) {
1686 raw_spin_unlock(&rq
->lock
);
1687 raw_spin_lock(&p
->pi_lock
);
1688 raw_spin_lock(&rq
->lock
);
1691 if (!(p
->state
& TASK_NORMAL
))
1695 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1697 ttwu_do_wakeup(rq
, p
, 0);
1698 ttwu_stat(p
, smp_processor_id(), 0);
1700 raw_spin_unlock(&p
->pi_lock
);
1704 * wake_up_process - Wake up a specific process
1705 * @p: The process to be woken up.
1707 * Attempt to wake up the nominated process and move it to the set of runnable
1710 * Return: 1 if the process was woken up, 0 if it was already running.
1712 * It may be assumed that this function implies a write memory barrier before
1713 * changing the task state if and only if any tasks are woken up.
1715 int wake_up_process(struct task_struct
*p
)
1717 WARN_ON(task_is_stopped_or_traced(p
));
1718 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1720 EXPORT_SYMBOL(wake_up_process
);
1722 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1724 return try_to_wake_up(p
, state
, 0);
1728 * Perform scheduler related setup for a newly forked process p.
1729 * p is forked by current.
1731 * __sched_fork() is basic setup used by init_idle() too:
1733 static void __sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1738 p
->se
.exec_start
= 0;
1739 p
->se
.sum_exec_runtime
= 0;
1740 p
->se
.prev_sum_exec_runtime
= 0;
1741 p
->se
.nr_migrations
= 0;
1743 INIT_LIST_HEAD(&p
->se
.group_node
);
1745 #ifdef CONFIG_SCHEDSTATS
1746 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1749 RB_CLEAR_NODE(&p
->dl
.rb_node
);
1750 hrtimer_init(&p
->dl
.dl_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1751 p
->dl
.dl_runtime
= p
->dl
.runtime
= 0;
1752 p
->dl
.dl_deadline
= p
->dl
.deadline
= 0;
1753 p
->dl
.dl_period
= 0;
1756 INIT_LIST_HEAD(&p
->rt
.run_list
);
1758 #ifdef CONFIG_PREEMPT_NOTIFIERS
1759 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1762 #ifdef CONFIG_NUMA_BALANCING
1763 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1764 p
->mm
->numa_next_scan
= jiffies
+ msecs_to_jiffies(sysctl_numa_balancing_scan_delay
);
1765 p
->mm
->numa_scan_seq
= 0;
1768 if (clone_flags
& CLONE_VM
)
1769 p
->numa_preferred_nid
= current
->numa_preferred_nid
;
1771 p
->numa_preferred_nid
= -1;
1773 p
->node_stamp
= 0ULL;
1774 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1775 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1776 p
->numa_work
.next
= &p
->numa_work
;
1777 p
->numa_faults_memory
= NULL
;
1778 p
->numa_faults_buffer_memory
= NULL
;
1779 p
->last_task_numa_placement
= 0;
1780 p
->last_sum_exec_runtime
= 0;
1782 INIT_LIST_HEAD(&p
->numa_entry
);
1783 p
->numa_group
= NULL
;
1784 #endif /* CONFIG_NUMA_BALANCING */
1787 #ifdef CONFIG_NUMA_BALANCING
1788 #ifdef CONFIG_SCHED_DEBUG
1789 void set_numabalancing_state(bool enabled
)
1792 sched_feat_set("NUMA");
1794 sched_feat_set("NO_NUMA");
1797 __read_mostly
bool numabalancing_enabled
;
1799 void set_numabalancing_state(bool enabled
)
1801 numabalancing_enabled
= enabled
;
1803 #endif /* CONFIG_SCHED_DEBUG */
1805 #ifdef CONFIG_PROC_SYSCTL
1806 int sysctl_numa_balancing(struct ctl_table
*table
, int write
,
1807 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1811 int state
= numabalancing_enabled
;
1813 if (write
&& !capable(CAP_SYS_ADMIN
))
1818 err
= proc_dointvec_minmax(&t
, write
, buffer
, lenp
, ppos
);
1822 set_numabalancing_state(state
);
1829 * fork()/clone()-time setup:
1831 int sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1833 unsigned long flags
;
1834 int cpu
= get_cpu();
1836 __sched_fork(clone_flags
, p
);
1838 * We mark the process as running here. This guarantees that
1839 * nobody will actually run it, and a signal or other external
1840 * event cannot wake it up and insert it on the runqueue either.
1842 p
->state
= TASK_RUNNING
;
1845 * Make sure we do not leak PI boosting priority to the child.
1847 p
->prio
= current
->normal_prio
;
1850 * Revert to default priority/policy on fork if requested.
1852 if (unlikely(p
->sched_reset_on_fork
)) {
1853 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
1854 p
->policy
= SCHED_NORMAL
;
1855 p
->static_prio
= NICE_TO_PRIO(0);
1857 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1858 p
->static_prio
= NICE_TO_PRIO(0);
1860 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1864 * We don't need the reset flag anymore after the fork. It has
1865 * fulfilled its duty:
1867 p
->sched_reset_on_fork
= 0;
1870 if (dl_prio(p
->prio
)) {
1873 } else if (rt_prio(p
->prio
)) {
1874 p
->sched_class
= &rt_sched_class
;
1876 p
->sched_class
= &fair_sched_class
;
1879 if (p
->sched_class
->task_fork
)
1880 p
->sched_class
->task_fork(p
);
1883 * The child is not yet in the pid-hash so no cgroup attach races,
1884 * and the cgroup is pinned to this child due to cgroup_fork()
1885 * is ran before sched_fork().
1887 * Silence PROVE_RCU.
1889 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1890 set_task_cpu(p
, cpu
);
1891 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1893 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1894 if (likely(sched_info_on()))
1895 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1897 #if defined(CONFIG_SMP)
1900 init_task_preempt_count(p
);
1902 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1903 RB_CLEAR_NODE(&p
->pushable_dl_tasks
);
1910 unsigned long to_ratio(u64 period
, u64 runtime
)
1912 if (runtime
== RUNTIME_INF
)
1916 * Doing this here saves a lot of checks in all
1917 * the calling paths, and returning zero seems
1918 * safe for them anyway.
1923 return div64_u64(runtime
<< 20, period
);
1927 inline struct dl_bw
*dl_bw_of(int i
)
1929 return &cpu_rq(i
)->rd
->dl_bw
;
1932 static inline int dl_bw_cpus(int i
)
1934 struct root_domain
*rd
= cpu_rq(i
)->rd
;
1937 for_each_cpu_and(i
, rd
->span
, cpu_active_mask
)
1943 inline struct dl_bw
*dl_bw_of(int i
)
1945 return &cpu_rq(i
)->dl
.dl_bw
;
1948 static inline int dl_bw_cpus(int i
)
1955 void __dl_clear(struct dl_bw
*dl_b
, u64 tsk_bw
)
1957 dl_b
->total_bw
-= tsk_bw
;
1961 void __dl_add(struct dl_bw
*dl_b
, u64 tsk_bw
)
1963 dl_b
->total_bw
+= tsk_bw
;
1967 bool __dl_overflow(struct dl_bw
*dl_b
, int cpus
, u64 old_bw
, u64 new_bw
)
1969 return dl_b
->bw
!= -1 &&
1970 dl_b
->bw
* cpus
< dl_b
->total_bw
- old_bw
+ new_bw
;
1974 * We must be sure that accepting a new task (or allowing changing the
1975 * parameters of an existing one) is consistent with the bandwidth
1976 * constraints. If yes, this function also accordingly updates the currently
1977 * allocated bandwidth to reflect the new situation.
1979 * This function is called while holding p's rq->lock.
1981 static int dl_overflow(struct task_struct
*p
, int policy
,
1982 const struct sched_attr
*attr
)
1985 struct dl_bw
*dl_b
= dl_bw_of(task_cpu(p
));
1986 u64 period
= attr
->sched_period
?: attr
->sched_deadline
;
1987 u64 runtime
= attr
->sched_runtime
;
1988 u64 new_bw
= dl_policy(policy
) ? to_ratio(period
, runtime
) : 0;
1991 if (new_bw
== p
->dl
.dl_bw
)
1995 * Either if a task, enters, leave, or stays -deadline but changes
1996 * its parameters, we may need to update accordingly the total
1997 * allocated bandwidth of the container.
1999 raw_spin_lock(&dl_b
->lock
);
2000 cpus
= dl_bw_cpus(task_cpu(p
));
2001 if (dl_policy(policy
) && !task_has_dl_policy(p
) &&
2002 !__dl_overflow(dl_b
, cpus
, 0, new_bw
)) {
2003 __dl_add(dl_b
, new_bw
);
2005 } else if (dl_policy(policy
) && task_has_dl_policy(p
) &&
2006 !__dl_overflow(dl_b
, cpus
, p
->dl
.dl_bw
, new_bw
)) {
2007 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2008 __dl_add(dl_b
, new_bw
);
2010 } else if (!dl_policy(policy
) && task_has_dl_policy(p
)) {
2011 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2014 raw_spin_unlock(&dl_b
->lock
);
2019 extern void init_dl_bw(struct dl_bw
*dl_b
);
2022 * wake_up_new_task - wake up a newly created task for the first time.
2024 * This function will do some initial scheduler statistics housekeeping
2025 * that must be done for every newly created context, then puts the task
2026 * on the runqueue and wakes it.
2028 void wake_up_new_task(struct task_struct
*p
)
2030 unsigned long flags
;
2033 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2036 * Fork balancing, do it here and not earlier because:
2037 * - cpus_allowed can change in the fork path
2038 * - any previously selected cpu might disappear through hotplug
2040 set_task_cpu(p
, select_task_rq(p
, task_cpu(p
), SD_BALANCE_FORK
, 0));
2043 /* Initialize new task's runnable average */
2044 init_task_runnable_average(p
);
2045 rq
= __task_rq_lock(p
);
2046 activate_task(rq
, p
, 0);
2048 trace_sched_wakeup_new(p
, true);
2049 check_preempt_curr(rq
, p
, WF_FORK
);
2051 if (p
->sched_class
->task_woken
)
2052 p
->sched_class
->task_woken(rq
, p
);
2054 task_rq_unlock(rq
, p
, &flags
);
2057 #ifdef CONFIG_PREEMPT_NOTIFIERS
2060 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2061 * @notifier: notifier struct to register
2063 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2065 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2067 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2070 * preempt_notifier_unregister - no longer interested in preemption notifications
2071 * @notifier: notifier struct to unregister
2073 * This is safe to call from within a preemption notifier.
2075 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2077 hlist_del(¬ifier
->link
);
2079 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2081 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2083 struct preempt_notifier
*notifier
;
2085 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2086 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2090 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2091 struct task_struct
*next
)
2093 struct preempt_notifier
*notifier
;
2095 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2096 notifier
->ops
->sched_out(notifier
, next
);
2099 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2101 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2106 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2107 struct task_struct
*next
)
2111 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2114 * prepare_task_switch - prepare to switch tasks
2115 * @rq: the runqueue preparing to switch
2116 * @prev: the current task that is being switched out
2117 * @next: the task we are going to switch to.
2119 * This is called with the rq lock held and interrupts off. It must
2120 * be paired with a subsequent finish_task_switch after the context
2123 * prepare_task_switch sets up locking and calls architecture specific
2127 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2128 struct task_struct
*next
)
2130 trace_sched_switch(prev
, next
);
2131 sched_info_switch(rq
, prev
, next
);
2132 perf_event_task_sched_out(prev
, next
);
2133 fire_sched_out_preempt_notifiers(prev
, next
);
2134 prepare_lock_switch(rq
, next
);
2135 prepare_arch_switch(next
);
2139 * finish_task_switch - clean up after a task-switch
2140 * @rq: runqueue associated with task-switch
2141 * @prev: the thread we just switched away from.
2143 * finish_task_switch must be called after the context switch, paired
2144 * with a prepare_task_switch call before the context switch.
2145 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2146 * and do any other architecture-specific cleanup actions.
2148 * Note that we may have delayed dropping an mm in context_switch(). If
2149 * so, we finish that here outside of the runqueue lock. (Doing it
2150 * with the lock held can cause deadlocks; see schedule() for
2153 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2154 __releases(rq
->lock
)
2156 struct mm_struct
*mm
= rq
->prev_mm
;
2162 * A task struct has one reference for the use as "current".
2163 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2164 * schedule one last time. The schedule call will never return, and
2165 * the scheduled task must drop that reference.
2166 * The test for TASK_DEAD must occur while the runqueue locks are
2167 * still held, otherwise prev could be scheduled on another cpu, die
2168 * there before we look at prev->state, and then the reference would
2170 * Manfred Spraul <manfred@colorfullife.com>
2172 prev_state
= prev
->state
;
2173 vtime_task_switch(prev
);
2174 finish_arch_switch(prev
);
2175 perf_event_task_sched_in(prev
, current
);
2176 finish_lock_switch(rq
, prev
);
2177 finish_arch_post_lock_switch();
2179 fire_sched_in_preempt_notifiers(current
);
2182 if (unlikely(prev_state
== TASK_DEAD
)) {
2183 if (prev
->sched_class
->task_dead
)
2184 prev
->sched_class
->task_dead(prev
);
2187 * Remove function-return probe instances associated with this
2188 * task and put them back on the free list.
2190 kprobe_flush_task(prev
);
2191 put_task_struct(prev
);
2194 tick_nohz_task_switch(current
);
2199 /* rq->lock is NOT held, but preemption is disabled */
2200 static inline void post_schedule(struct rq
*rq
)
2202 if (rq
->post_schedule
) {
2203 unsigned long flags
;
2205 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2206 if (rq
->curr
->sched_class
->post_schedule
)
2207 rq
->curr
->sched_class
->post_schedule(rq
);
2208 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2210 rq
->post_schedule
= 0;
2216 static inline void post_schedule(struct rq
*rq
)
2223 * schedule_tail - first thing a freshly forked thread must call.
2224 * @prev: the thread we just switched away from.
2226 asmlinkage __visible
void schedule_tail(struct task_struct
*prev
)
2227 __releases(rq
->lock
)
2229 struct rq
*rq
= this_rq();
2231 finish_task_switch(rq
, prev
);
2234 * FIXME: do we need to worry about rq being invalidated by the
2239 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2240 /* In this case, finish_task_switch does not reenable preemption */
2243 if (current
->set_child_tid
)
2244 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2248 * context_switch - switch to the new MM and the new
2249 * thread's register state.
2252 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2253 struct task_struct
*next
)
2255 struct mm_struct
*mm
, *oldmm
;
2257 prepare_task_switch(rq
, prev
, next
);
2260 oldmm
= prev
->active_mm
;
2262 * For paravirt, this is coupled with an exit in switch_to to
2263 * combine the page table reload and the switch backend into
2266 arch_start_context_switch(prev
);
2269 next
->active_mm
= oldmm
;
2270 atomic_inc(&oldmm
->mm_count
);
2271 enter_lazy_tlb(oldmm
, next
);
2273 switch_mm(oldmm
, mm
, next
);
2276 prev
->active_mm
= NULL
;
2277 rq
->prev_mm
= oldmm
;
2280 * Since the runqueue lock will be released by the next
2281 * task (which is an invalid locking op but in the case
2282 * of the scheduler it's an obvious special-case), so we
2283 * do an early lockdep release here:
2285 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2286 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2289 context_tracking_task_switch(prev
, next
);
2290 /* Here we just switch the register state and the stack. */
2291 switch_to(prev
, next
, prev
);
2295 * this_rq must be evaluated again because prev may have moved
2296 * CPUs since it called schedule(), thus the 'rq' on its stack
2297 * frame will be invalid.
2299 finish_task_switch(this_rq(), prev
);
2303 * nr_running and nr_context_switches:
2305 * externally visible scheduler statistics: current number of runnable
2306 * threads, total number of context switches performed since bootup.
2308 unsigned long nr_running(void)
2310 unsigned long i
, sum
= 0;
2312 for_each_online_cpu(i
)
2313 sum
+= cpu_rq(i
)->nr_running
;
2318 unsigned long long nr_context_switches(void)
2321 unsigned long long sum
= 0;
2323 for_each_possible_cpu(i
)
2324 sum
+= cpu_rq(i
)->nr_switches
;
2329 unsigned long nr_iowait(void)
2331 unsigned long i
, sum
= 0;
2333 for_each_possible_cpu(i
)
2334 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2339 unsigned long nr_iowait_cpu(int cpu
)
2341 struct rq
*this = cpu_rq(cpu
);
2342 return atomic_read(&this->nr_iowait
);
2348 * sched_exec - execve() is a valuable balancing opportunity, because at
2349 * this point the task has the smallest effective memory and cache footprint.
2351 void sched_exec(void)
2353 struct task_struct
*p
= current
;
2354 unsigned long flags
;
2357 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2358 dest_cpu
= p
->sched_class
->select_task_rq(p
, task_cpu(p
), SD_BALANCE_EXEC
, 0);
2359 if (dest_cpu
== smp_processor_id())
2362 if (likely(cpu_active(dest_cpu
))) {
2363 struct migration_arg arg
= { p
, dest_cpu
};
2365 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2366 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2370 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2375 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2376 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2378 EXPORT_PER_CPU_SYMBOL(kstat
);
2379 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2382 * Return any ns on the sched_clock that have not yet been accounted in
2383 * @p in case that task is currently running.
2385 * Called with task_rq_lock() held on @rq.
2387 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2391 if (task_current(rq
, p
)) {
2392 update_rq_clock(rq
);
2393 ns
= rq_clock_task(rq
) - p
->se
.exec_start
;
2401 unsigned long long task_delta_exec(struct task_struct
*p
)
2403 unsigned long flags
;
2407 rq
= task_rq_lock(p
, &flags
);
2408 ns
= do_task_delta_exec(p
, rq
);
2409 task_rq_unlock(rq
, p
, &flags
);
2415 * Return accounted runtime for the task.
2416 * In case the task is currently running, return the runtime plus current's
2417 * pending runtime that have not been accounted yet.
2419 unsigned long long task_sched_runtime(struct task_struct
*p
)
2421 unsigned long flags
;
2425 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2427 * 64-bit doesn't need locks to atomically read a 64bit value.
2428 * So we have a optimization chance when the task's delta_exec is 0.
2429 * Reading ->on_cpu is racy, but this is ok.
2431 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2432 * If we race with it entering cpu, unaccounted time is 0. This is
2433 * indistinguishable from the read occurring a few cycles earlier.
2436 return p
->se
.sum_exec_runtime
;
2439 rq
= task_rq_lock(p
, &flags
);
2440 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2441 task_rq_unlock(rq
, p
, &flags
);
2447 * This function gets called by the timer code, with HZ frequency.
2448 * We call it with interrupts disabled.
2450 void scheduler_tick(void)
2452 int cpu
= smp_processor_id();
2453 struct rq
*rq
= cpu_rq(cpu
);
2454 struct task_struct
*curr
= rq
->curr
;
2458 raw_spin_lock(&rq
->lock
);
2459 update_rq_clock(rq
);
2460 curr
->sched_class
->task_tick(rq
, curr
, 0);
2461 update_cpu_load_active(rq
);
2462 raw_spin_unlock(&rq
->lock
);
2464 perf_event_task_tick();
2467 rq
->idle_balance
= idle_cpu(cpu
);
2468 trigger_load_balance(rq
);
2470 rq_last_tick_reset(rq
);
2473 #ifdef CONFIG_NO_HZ_FULL
2475 * scheduler_tick_max_deferment
2477 * Keep at least one tick per second when a single
2478 * active task is running because the scheduler doesn't
2479 * yet completely support full dynticks environment.
2481 * This makes sure that uptime, CFS vruntime, load
2482 * balancing, etc... continue to move forward, even
2483 * with a very low granularity.
2485 * Return: Maximum deferment in nanoseconds.
2487 u64
scheduler_tick_max_deferment(void)
2489 struct rq
*rq
= this_rq();
2490 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2492 next
= rq
->last_sched_tick
+ HZ
;
2494 if (time_before_eq(next
, now
))
2497 return jiffies_to_nsecs(next
- now
);
2501 notrace
unsigned long get_parent_ip(unsigned long addr
)
2503 if (in_lock_functions(addr
)) {
2504 addr
= CALLER_ADDR2
;
2505 if (in_lock_functions(addr
))
2506 addr
= CALLER_ADDR3
;
2511 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2512 defined(CONFIG_PREEMPT_TRACER))
2514 void __kprobes
preempt_count_add(int val
)
2516 #ifdef CONFIG_DEBUG_PREEMPT
2520 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2523 __preempt_count_add(val
);
2524 #ifdef CONFIG_DEBUG_PREEMPT
2526 * Spinlock count overflowing soon?
2528 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2531 if (preempt_count() == val
) {
2532 unsigned long ip
= get_parent_ip(CALLER_ADDR1
);
2533 #ifdef CONFIG_DEBUG_PREEMPT
2534 current
->preempt_disable_ip
= ip
;
2536 trace_preempt_off(CALLER_ADDR0
, ip
);
2539 EXPORT_SYMBOL(preempt_count_add
);
2541 void __kprobes
preempt_count_sub(int val
)
2543 #ifdef CONFIG_DEBUG_PREEMPT
2547 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2550 * Is the spinlock portion underflowing?
2552 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2553 !(preempt_count() & PREEMPT_MASK
)))
2557 if (preempt_count() == val
)
2558 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2559 __preempt_count_sub(val
);
2561 EXPORT_SYMBOL(preempt_count_sub
);
2566 * Print scheduling while atomic bug:
2568 static noinline
void __schedule_bug(struct task_struct
*prev
)
2570 if (oops_in_progress
)
2573 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2574 prev
->comm
, prev
->pid
, preempt_count());
2576 debug_show_held_locks(prev
);
2578 if (irqs_disabled())
2579 print_irqtrace_events(prev
);
2580 #ifdef CONFIG_DEBUG_PREEMPT
2581 if (in_atomic_preempt_off()) {
2582 pr_err("Preemption disabled at:");
2583 print_ip_sym(current
->preempt_disable_ip
);
2588 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2592 * Various schedule()-time debugging checks and statistics:
2594 static inline void schedule_debug(struct task_struct
*prev
)
2597 * Test if we are atomic. Since do_exit() needs to call into
2598 * schedule() atomically, we ignore that path. Otherwise whine
2599 * if we are scheduling when we should not.
2601 if (unlikely(in_atomic_preempt_off() && prev
->state
!= TASK_DEAD
))
2602 __schedule_bug(prev
);
2605 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2607 schedstat_inc(this_rq(), sched_count
);
2611 * Pick up the highest-prio task:
2613 static inline struct task_struct
*
2614 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
2616 const struct sched_class
*class = &fair_sched_class
;
2617 struct task_struct
*p
;
2620 * Optimization: we know that if all tasks are in
2621 * the fair class we can call that function directly:
2623 if (likely(prev
->sched_class
== class &&
2624 rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2625 p
= fair_sched_class
.pick_next_task(rq
, prev
);
2626 if (unlikely(p
== RETRY_TASK
))
2629 /* assumes fair_sched_class->next == idle_sched_class */
2631 p
= idle_sched_class
.pick_next_task(rq
, prev
);
2637 for_each_class(class) {
2638 p
= class->pick_next_task(rq
, prev
);
2640 if (unlikely(p
== RETRY_TASK
))
2646 BUG(); /* the idle class will always have a runnable task */
2650 * __schedule() is the main scheduler function.
2652 * The main means of driving the scheduler and thus entering this function are:
2654 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2656 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2657 * paths. For example, see arch/x86/entry_64.S.
2659 * To drive preemption between tasks, the scheduler sets the flag in timer
2660 * interrupt handler scheduler_tick().
2662 * 3. Wakeups don't really cause entry into schedule(). They add a
2663 * task to the run-queue and that's it.
2665 * Now, if the new task added to the run-queue preempts the current
2666 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2667 * called on the nearest possible occasion:
2669 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2671 * - in syscall or exception context, at the next outmost
2672 * preempt_enable(). (this might be as soon as the wake_up()'s
2675 * - in IRQ context, return from interrupt-handler to
2676 * preemptible context
2678 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2681 * - cond_resched() call
2682 * - explicit schedule() call
2683 * - return from syscall or exception to user-space
2684 * - return from interrupt-handler to user-space
2686 static void __sched
__schedule(void)
2688 struct task_struct
*prev
, *next
;
2689 unsigned long *switch_count
;
2695 cpu
= smp_processor_id();
2697 rcu_note_context_switch(cpu
);
2700 schedule_debug(prev
);
2702 if (sched_feat(HRTICK
))
2706 * Make sure that signal_pending_state()->signal_pending() below
2707 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2708 * done by the caller to avoid the race with signal_wake_up().
2710 smp_mb__before_spinlock();
2711 raw_spin_lock_irq(&rq
->lock
);
2713 switch_count
= &prev
->nivcsw
;
2714 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2715 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2716 prev
->state
= TASK_RUNNING
;
2718 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2722 * If a worker went to sleep, notify and ask workqueue
2723 * whether it wants to wake up a task to maintain
2726 if (prev
->flags
& PF_WQ_WORKER
) {
2727 struct task_struct
*to_wakeup
;
2729 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2731 try_to_wake_up_local(to_wakeup
);
2734 switch_count
= &prev
->nvcsw
;
2737 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
2738 update_rq_clock(rq
);
2740 next
= pick_next_task(rq
, prev
);
2741 clear_tsk_need_resched(prev
);
2742 clear_preempt_need_resched();
2743 rq
->skip_clock_update
= 0;
2745 if (likely(prev
!= next
)) {
2750 context_switch(rq
, prev
, next
); /* unlocks the rq */
2752 * The context switch have flipped the stack from under us
2753 * and restored the local variables which were saved when
2754 * this task called schedule() in the past. prev == current
2755 * is still correct, but it can be moved to another cpu/rq.
2757 cpu
= smp_processor_id();
2760 raw_spin_unlock_irq(&rq
->lock
);
2764 sched_preempt_enable_no_resched();
2769 static inline void sched_submit_work(struct task_struct
*tsk
)
2771 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2774 * If we are going to sleep and we have plugged IO queued,
2775 * make sure to submit it to avoid deadlocks.
2777 if (blk_needs_flush_plug(tsk
))
2778 blk_schedule_flush_plug(tsk
);
2781 asmlinkage __visible
void __sched
schedule(void)
2783 struct task_struct
*tsk
= current
;
2785 sched_submit_work(tsk
);
2788 EXPORT_SYMBOL(schedule
);
2790 #ifdef CONFIG_CONTEXT_TRACKING
2791 asmlinkage __visible
void __sched
schedule_user(void)
2794 * If we come here after a random call to set_need_resched(),
2795 * or we have been woken up remotely but the IPI has not yet arrived,
2796 * we haven't yet exited the RCU idle mode. Do it here manually until
2797 * we find a better solution.
2806 * schedule_preempt_disabled - called with preemption disabled
2808 * Returns with preemption disabled. Note: preempt_count must be 1
2810 void __sched
schedule_preempt_disabled(void)
2812 sched_preempt_enable_no_resched();
2817 #ifdef CONFIG_PREEMPT
2819 * this is the entry point to schedule() from in-kernel preemption
2820 * off of preempt_enable. Kernel preemptions off return from interrupt
2821 * occur there and call schedule directly.
2823 asmlinkage __visible
void __sched notrace
preempt_schedule(void)
2826 * If there is a non-zero preempt_count or interrupts are disabled,
2827 * we do not want to preempt the current task. Just return..
2829 if (likely(!preemptible()))
2833 __preempt_count_add(PREEMPT_ACTIVE
);
2835 __preempt_count_sub(PREEMPT_ACTIVE
);
2838 * Check again in case we missed a preemption opportunity
2839 * between schedule and now.
2842 } while (need_resched());
2844 EXPORT_SYMBOL(preempt_schedule
);
2845 #endif /* CONFIG_PREEMPT */
2848 * this is the entry point to schedule() from kernel preemption
2849 * off of irq context.
2850 * Note, that this is called and return with irqs disabled. This will
2851 * protect us against recursive calling from irq.
2853 asmlinkage __visible
void __sched
preempt_schedule_irq(void)
2855 enum ctx_state prev_state
;
2857 /* Catch callers which need to be fixed */
2858 BUG_ON(preempt_count() || !irqs_disabled());
2860 prev_state
= exception_enter();
2863 __preempt_count_add(PREEMPT_ACTIVE
);
2866 local_irq_disable();
2867 __preempt_count_sub(PREEMPT_ACTIVE
);
2870 * Check again in case we missed a preemption opportunity
2871 * between schedule and now.
2874 } while (need_resched());
2876 exception_exit(prev_state
);
2879 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2882 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2884 EXPORT_SYMBOL(default_wake_function
);
2886 #ifdef CONFIG_RT_MUTEXES
2889 * rt_mutex_setprio - set the current priority of a task
2891 * @prio: prio value (kernel-internal form)
2893 * This function changes the 'effective' priority of a task. It does
2894 * not touch ->normal_prio like __setscheduler().
2896 * Used by the rt_mutex code to implement priority inheritance
2897 * logic. Call site only calls if the priority of the task changed.
2899 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
2901 int oldprio
, on_rq
, running
, enqueue_flag
= 0;
2903 const struct sched_class
*prev_class
;
2905 BUG_ON(prio
> MAX_PRIO
);
2907 rq
= __task_rq_lock(p
);
2910 * Idle task boosting is a nono in general. There is one
2911 * exception, when PREEMPT_RT and NOHZ is active:
2913 * The idle task calls get_next_timer_interrupt() and holds
2914 * the timer wheel base->lock on the CPU and another CPU wants
2915 * to access the timer (probably to cancel it). We can safely
2916 * ignore the boosting request, as the idle CPU runs this code
2917 * with interrupts disabled and will complete the lock
2918 * protected section without being interrupted. So there is no
2919 * real need to boost.
2921 if (unlikely(p
== rq
->idle
)) {
2922 WARN_ON(p
!= rq
->curr
);
2923 WARN_ON(p
->pi_blocked_on
);
2927 trace_sched_pi_setprio(p
, prio
);
2928 p
->pi_top_task
= rt_mutex_get_top_task(p
);
2930 prev_class
= p
->sched_class
;
2932 running
= task_current(rq
, p
);
2934 dequeue_task(rq
, p
, 0);
2936 p
->sched_class
->put_prev_task(rq
, p
);
2939 * Boosting condition are:
2940 * 1. -rt task is running and holds mutex A
2941 * --> -dl task blocks on mutex A
2943 * 2. -dl task is running and holds mutex A
2944 * --> -dl task blocks on mutex A and could preempt the
2947 if (dl_prio(prio
)) {
2948 if (!dl_prio(p
->normal_prio
) || (p
->pi_top_task
&&
2949 dl_entity_preempt(&p
->pi_top_task
->dl
, &p
->dl
))) {
2950 p
->dl
.dl_boosted
= 1;
2951 p
->dl
.dl_throttled
= 0;
2952 enqueue_flag
= ENQUEUE_REPLENISH
;
2954 p
->dl
.dl_boosted
= 0;
2955 p
->sched_class
= &dl_sched_class
;
2956 } else if (rt_prio(prio
)) {
2957 if (dl_prio(oldprio
))
2958 p
->dl
.dl_boosted
= 0;
2960 enqueue_flag
= ENQUEUE_HEAD
;
2961 p
->sched_class
= &rt_sched_class
;
2963 if (dl_prio(oldprio
))
2964 p
->dl
.dl_boosted
= 0;
2965 p
->sched_class
= &fair_sched_class
;
2971 p
->sched_class
->set_curr_task(rq
);
2973 enqueue_task(rq
, p
, enqueue_flag
);
2975 check_class_changed(rq
, p
, prev_class
, oldprio
);
2977 __task_rq_unlock(rq
);
2981 void set_user_nice(struct task_struct
*p
, long nice
)
2983 int old_prio
, delta
, on_rq
;
2984 unsigned long flags
;
2987 if (task_nice(p
) == nice
|| nice
< MIN_NICE
|| nice
> MAX_NICE
)
2990 * We have to be careful, if called from sys_setpriority(),
2991 * the task might be in the middle of scheduling on another CPU.
2993 rq
= task_rq_lock(p
, &flags
);
2995 * The RT priorities are set via sched_setscheduler(), but we still
2996 * allow the 'normal' nice value to be set - but as expected
2997 * it wont have any effect on scheduling until the task is
2998 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3000 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
3001 p
->static_prio
= NICE_TO_PRIO(nice
);
3006 dequeue_task(rq
, p
, 0);
3008 p
->static_prio
= NICE_TO_PRIO(nice
);
3011 p
->prio
= effective_prio(p
);
3012 delta
= p
->prio
- old_prio
;
3015 enqueue_task(rq
, p
, 0);
3017 * If the task increased its priority or is running and
3018 * lowered its priority, then reschedule its CPU:
3020 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3021 resched_task(rq
->curr
);
3024 task_rq_unlock(rq
, p
, &flags
);
3026 EXPORT_SYMBOL(set_user_nice
);
3029 * can_nice - check if a task can reduce its nice value
3033 int can_nice(const struct task_struct
*p
, const int nice
)
3035 /* convert nice value [19,-20] to rlimit style value [1,40] */
3036 int nice_rlim
= nice_to_rlimit(nice
);
3038 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3039 capable(CAP_SYS_NICE
));
3042 #ifdef __ARCH_WANT_SYS_NICE
3045 * sys_nice - change the priority of the current process.
3046 * @increment: priority increment
3048 * sys_setpriority is a more generic, but much slower function that
3049 * does similar things.
3051 SYSCALL_DEFINE1(nice
, int, increment
)
3056 * Setpriority might change our priority at the same moment.
3057 * We don't have to worry. Conceptually one call occurs first
3058 * and we have a single winner.
3060 increment
= clamp(increment
, -NICE_WIDTH
, NICE_WIDTH
);
3061 nice
= task_nice(current
) + increment
;
3063 nice
= clamp_val(nice
, MIN_NICE
, MAX_NICE
);
3064 if (increment
< 0 && !can_nice(current
, nice
))
3067 retval
= security_task_setnice(current
, nice
);
3071 set_user_nice(current
, nice
);
3078 * task_prio - return the priority value of a given task.
3079 * @p: the task in question.
3081 * Return: The priority value as seen by users in /proc.
3082 * RT tasks are offset by -200. Normal tasks are centered
3083 * around 0, value goes from -16 to +15.
3085 int task_prio(const struct task_struct
*p
)
3087 return p
->prio
- MAX_RT_PRIO
;
3091 * idle_cpu - is a given cpu idle currently?
3092 * @cpu: the processor in question.
3094 * Return: 1 if the CPU is currently idle. 0 otherwise.
3096 int idle_cpu(int cpu
)
3098 struct rq
*rq
= cpu_rq(cpu
);
3100 if (rq
->curr
!= rq
->idle
)
3107 if (!llist_empty(&rq
->wake_list
))
3115 * idle_task - return the idle task for a given cpu.
3116 * @cpu: the processor in question.
3118 * Return: The idle task for the cpu @cpu.
3120 struct task_struct
*idle_task(int cpu
)
3122 return cpu_rq(cpu
)->idle
;
3126 * find_process_by_pid - find a process with a matching PID value.
3127 * @pid: the pid in question.
3129 * The task of @pid, if found. %NULL otherwise.
3131 static struct task_struct
*find_process_by_pid(pid_t pid
)
3133 return pid
? find_task_by_vpid(pid
) : current
;
3137 * This function initializes the sched_dl_entity of a newly becoming
3138 * SCHED_DEADLINE task.
3140 * Only the static values are considered here, the actual runtime and the
3141 * absolute deadline will be properly calculated when the task is enqueued
3142 * for the first time with its new policy.
3145 __setparam_dl(struct task_struct
*p
, const struct sched_attr
*attr
)
3147 struct sched_dl_entity
*dl_se
= &p
->dl
;
3149 init_dl_task_timer(dl_se
);
3150 dl_se
->dl_runtime
= attr
->sched_runtime
;
3151 dl_se
->dl_deadline
= attr
->sched_deadline
;
3152 dl_se
->dl_period
= attr
->sched_period
?: dl_se
->dl_deadline
;
3153 dl_se
->flags
= attr
->sched_flags
;
3154 dl_se
->dl_bw
= to_ratio(dl_se
->dl_period
, dl_se
->dl_runtime
);
3155 dl_se
->dl_throttled
= 0;
3157 dl_se
->dl_yielded
= 0;
3160 static void __setscheduler_params(struct task_struct
*p
,
3161 const struct sched_attr
*attr
)
3163 int policy
= attr
->sched_policy
;
3165 if (policy
== -1) /* setparam */
3170 if (dl_policy(policy
))
3171 __setparam_dl(p
, attr
);
3172 else if (fair_policy(policy
))
3173 p
->static_prio
= NICE_TO_PRIO(attr
->sched_nice
);
3176 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3177 * !rt_policy. Always setting this ensures that things like
3178 * getparam()/getattr() don't report silly values for !rt tasks.
3180 p
->rt_priority
= attr
->sched_priority
;
3181 p
->normal_prio
= normal_prio(p
);
3185 /* Actually do priority change: must hold pi & rq lock. */
3186 static void __setscheduler(struct rq
*rq
, struct task_struct
*p
,
3187 const struct sched_attr
*attr
)
3189 __setscheduler_params(p
, attr
);
3192 * If we get here, there was no pi waiters boosting the
3193 * task. It is safe to use the normal prio.
3195 p
->prio
= normal_prio(p
);
3197 if (dl_prio(p
->prio
))
3198 p
->sched_class
= &dl_sched_class
;
3199 else if (rt_prio(p
->prio
))
3200 p
->sched_class
= &rt_sched_class
;
3202 p
->sched_class
= &fair_sched_class
;
3206 __getparam_dl(struct task_struct
*p
, struct sched_attr
*attr
)
3208 struct sched_dl_entity
*dl_se
= &p
->dl
;
3210 attr
->sched_priority
= p
->rt_priority
;
3211 attr
->sched_runtime
= dl_se
->dl_runtime
;
3212 attr
->sched_deadline
= dl_se
->dl_deadline
;
3213 attr
->sched_period
= dl_se
->dl_period
;
3214 attr
->sched_flags
= dl_se
->flags
;
3218 * This function validates the new parameters of a -deadline task.
3219 * We ask for the deadline not being zero, and greater or equal
3220 * than the runtime, as well as the period of being zero or
3221 * greater than deadline. Furthermore, we have to be sure that
3222 * user parameters are above the internal resolution of 1us (we
3223 * check sched_runtime only since it is always the smaller one) and
3224 * below 2^63 ns (we have to check both sched_deadline and
3225 * sched_period, as the latter can be zero).
3228 __checkparam_dl(const struct sched_attr
*attr
)
3231 if (attr
->sched_deadline
== 0)
3235 * Since we truncate DL_SCALE bits, make sure we're at least
3238 if (attr
->sched_runtime
< (1ULL << DL_SCALE
))
3242 * Since we use the MSB for wrap-around and sign issues, make
3243 * sure it's not set (mind that period can be equal to zero).
3245 if (attr
->sched_deadline
& (1ULL << 63) ||
3246 attr
->sched_period
& (1ULL << 63))
3249 /* runtime <= deadline <= period (if period != 0) */
3250 if ((attr
->sched_period
!= 0 &&
3251 attr
->sched_period
< attr
->sched_deadline
) ||
3252 attr
->sched_deadline
< attr
->sched_runtime
)
3259 * check the target process has a UID that matches the current process's
3261 static bool check_same_owner(struct task_struct
*p
)
3263 const struct cred
*cred
= current_cred(), *pcred
;
3267 pcred
= __task_cred(p
);
3268 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3269 uid_eq(cred
->euid
, pcred
->uid
));
3274 static int __sched_setscheduler(struct task_struct
*p
,
3275 const struct sched_attr
*attr
,
3278 int newprio
= dl_policy(attr
->sched_policy
) ? MAX_DL_PRIO
- 1 :
3279 MAX_RT_PRIO
- 1 - attr
->sched_priority
;
3280 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
3281 int policy
= attr
->sched_policy
;
3282 unsigned long flags
;
3283 const struct sched_class
*prev_class
;
3287 /* may grab non-irq protected spin_locks */
3288 BUG_ON(in_interrupt());
3290 /* double check policy once rq lock held */
3292 reset_on_fork
= p
->sched_reset_on_fork
;
3293 policy
= oldpolicy
= p
->policy
;
3295 reset_on_fork
= !!(attr
->sched_flags
& SCHED_FLAG_RESET_ON_FORK
);
3297 if (policy
!= SCHED_DEADLINE
&&
3298 policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3299 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3300 policy
!= SCHED_IDLE
)
3304 if (attr
->sched_flags
& ~(SCHED_FLAG_RESET_ON_FORK
))
3308 * Valid priorities for SCHED_FIFO and SCHED_RR are
3309 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3310 * SCHED_BATCH and SCHED_IDLE is 0.
3312 if ((p
->mm
&& attr
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3313 (!p
->mm
&& attr
->sched_priority
> MAX_RT_PRIO
-1))
3315 if ((dl_policy(policy
) && !__checkparam_dl(attr
)) ||
3316 (rt_policy(policy
) != (attr
->sched_priority
!= 0)))
3320 * Allow unprivileged RT tasks to decrease priority:
3322 if (user
&& !capable(CAP_SYS_NICE
)) {
3323 if (fair_policy(policy
)) {
3324 if (attr
->sched_nice
< task_nice(p
) &&
3325 !can_nice(p
, attr
->sched_nice
))
3329 if (rt_policy(policy
)) {
3330 unsigned long rlim_rtprio
=
3331 task_rlimit(p
, RLIMIT_RTPRIO
);
3333 /* can't set/change the rt policy */
3334 if (policy
!= p
->policy
&& !rlim_rtprio
)
3337 /* can't increase priority */
3338 if (attr
->sched_priority
> p
->rt_priority
&&
3339 attr
->sched_priority
> rlim_rtprio
)
3344 * Can't set/change SCHED_DEADLINE policy at all for now
3345 * (safest behavior); in the future we would like to allow
3346 * unprivileged DL tasks to increase their relative deadline
3347 * or reduce their runtime (both ways reducing utilization)
3349 if (dl_policy(policy
))
3353 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3354 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3356 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3357 if (!can_nice(p
, task_nice(p
)))
3361 /* can't change other user's priorities */
3362 if (!check_same_owner(p
))
3365 /* Normal users shall not reset the sched_reset_on_fork flag */
3366 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3371 retval
= security_task_setscheduler(p
);
3377 * make sure no PI-waiters arrive (or leave) while we are
3378 * changing the priority of the task:
3380 * To be able to change p->policy safely, the appropriate
3381 * runqueue lock must be held.
3383 rq
= task_rq_lock(p
, &flags
);
3386 * Changing the policy of the stop threads its a very bad idea
3388 if (p
== rq
->stop
) {
3389 task_rq_unlock(rq
, p
, &flags
);
3394 * If not changing anything there's no need to proceed further,
3395 * but store a possible modification of reset_on_fork.
3397 if (unlikely(policy
== p
->policy
)) {
3398 if (fair_policy(policy
) && attr
->sched_nice
!= task_nice(p
))
3400 if (rt_policy(policy
) && attr
->sched_priority
!= p
->rt_priority
)
3402 if (dl_policy(policy
))
3405 p
->sched_reset_on_fork
= reset_on_fork
;
3406 task_rq_unlock(rq
, p
, &flags
);
3412 #ifdef CONFIG_RT_GROUP_SCHED
3414 * Do not allow realtime tasks into groups that have no runtime
3417 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3418 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3419 !task_group_is_autogroup(task_group(p
))) {
3420 task_rq_unlock(rq
, p
, &flags
);
3425 if (dl_bandwidth_enabled() && dl_policy(policy
)) {
3426 cpumask_t
*span
= rq
->rd
->span
;
3429 * Don't allow tasks with an affinity mask smaller than
3430 * the entire root_domain to become SCHED_DEADLINE. We
3431 * will also fail if there's no bandwidth available.
3433 if (!cpumask_subset(span
, &p
->cpus_allowed
) ||
3434 rq
->rd
->dl_bw
.bw
== 0) {
3435 task_rq_unlock(rq
, p
, &flags
);
3442 /* recheck policy now with rq lock held */
3443 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3444 policy
= oldpolicy
= -1;
3445 task_rq_unlock(rq
, p
, &flags
);
3450 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3451 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3454 if ((dl_policy(policy
) || dl_task(p
)) && dl_overflow(p
, policy
, attr
)) {
3455 task_rq_unlock(rq
, p
, &flags
);
3459 p
->sched_reset_on_fork
= reset_on_fork
;
3463 * Special case for priority boosted tasks.
3465 * If the new priority is lower or equal (user space view)
3466 * than the current (boosted) priority, we just store the new
3467 * normal parameters and do not touch the scheduler class and
3468 * the runqueue. This will be done when the task deboost
3471 if (rt_mutex_check_prio(p
, newprio
)) {
3472 __setscheduler_params(p
, attr
);
3473 task_rq_unlock(rq
, p
, &flags
);
3478 running
= task_current(rq
, p
);
3480 dequeue_task(rq
, p
, 0);
3482 p
->sched_class
->put_prev_task(rq
, p
);
3484 prev_class
= p
->sched_class
;
3485 __setscheduler(rq
, p
, attr
);
3488 p
->sched_class
->set_curr_task(rq
);
3491 * We enqueue to tail when the priority of a task is
3492 * increased (user space view).
3494 enqueue_task(rq
, p
, oldprio
<= p
->prio
? ENQUEUE_HEAD
: 0);
3497 check_class_changed(rq
, p
, prev_class
, oldprio
);
3498 task_rq_unlock(rq
, p
, &flags
);
3500 rt_mutex_adjust_pi(p
);
3505 static int _sched_setscheduler(struct task_struct
*p
, int policy
,
3506 const struct sched_param
*param
, bool check
)
3508 struct sched_attr attr
= {
3509 .sched_policy
= policy
,
3510 .sched_priority
= param
->sched_priority
,
3511 .sched_nice
= PRIO_TO_NICE(p
->static_prio
),
3515 * Fixup the legacy SCHED_RESET_ON_FORK hack
3517 if (policy
& SCHED_RESET_ON_FORK
) {
3518 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3519 policy
&= ~SCHED_RESET_ON_FORK
;
3520 attr
.sched_policy
= policy
;
3523 return __sched_setscheduler(p
, &attr
, check
);
3526 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3527 * @p: the task in question.
3528 * @policy: new policy.
3529 * @param: structure containing the new RT priority.
3531 * Return: 0 on success. An error code otherwise.
3533 * NOTE that the task may be already dead.
3535 int sched_setscheduler(struct task_struct
*p
, int policy
,
3536 const struct sched_param
*param
)
3538 return _sched_setscheduler(p
, policy
, param
, true);
3540 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3542 int sched_setattr(struct task_struct
*p
, const struct sched_attr
*attr
)
3544 return __sched_setscheduler(p
, attr
, true);
3546 EXPORT_SYMBOL_GPL(sched_setattr
);
3549 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3550 * @p: the task in question.
3551 * @policy: new policy.
3552 * @param: structure containing the new RT priority.
3554 * Just like sched_setscheduler, only don't bother checking if the
3555 * current context has permission. For example, this is needed in
3556 * stop_machine(): we create temporary high priority worker threads,
3557 * but our caller might not have that capability.
3559 * Return: 0 on success. An error code otherwise.
3561 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3562 const struct sched_param
*param
)
3564 return _sched_setscheduler(p
, policy
, param
, false);
3568 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3570 struct sched_param lparam
;
3571 struct task_struct
*p
;
3574 if (!param
|| pid
< 0)
3576 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3581 p
= find_process_by_pid(pid
);
3583 retval
= sched_setscheduler(p
, policy
, &lparam
);
3590 * Mimics kernel/events/core.c perf_copy_attr().
3592 static int sched_copy_attr(struct sched_attr __user
*uattr
,
3593 struct sched_attr
*attr
)
3598 if (!access_ok(VERIFY_WRITE
, uattr
, SCHED_ATTR_SIZE_VER0
))
3602 * zero the full structure, so that a short copy will be nice.
3604 memset(attr
, 0, sizeof(*attr
));
3606 ret
= get_user(size
, &uattr
->size
);
3610 if (size
> PAGE_SIZE
) /* silly large */
3613 if (!size
) /* abi compat */
3614 size
= SCHED_ATTR_SIZE_VER0
;
3616 if (size
< SCHED_ATTR_SIZE_VER0
)
3620 * If we're handed a bigger struct than we know of,
3621 * ensure all the unknown bits are 0 - i.e. new
3622 * user-space does not rely on any kernel feature
3623 * extensions we dont know about yet.
3625 if (size
> sizeof(*attr
)) {
3626 unsigned char __user
*addr
;
3627 unsigned char __user
*end
;
3630 addr
= (void __user
*)uattr
+ sizeof(*attr
);
3631 end
= (void __user
*)uattr
+ size
;
3633 for (; addr
< end
; addr
++) {
3634 ret
= get_user(val
, addr
);
3640 size
= sizeof(*attr
);
3643 ret
= copy_from_user(attr
, uattr
, size
);
3648 * XXX: do we want to be lenient like existing syscalls; or do we want
3649 * to be strict and return an error on out-of-bounds values?
3651 attr
->sched_nice
= clamp(attr
->sched_nice
, MIN_NICE
, MAX_NICE
);
3656 put_user(sizeof(*attr
), &uattr
->size
);
3661 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3662 * @pid: the pid in question.
3663 * @policy: new policy.
3664 * @param: structure containing the new RT priority.
3666 * Return: 0 on success. An error code otherwise.
3668 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3669 struct sched_param __user
*, param
)
3671 /* negative values for policy are not valid */
3675 return do_sched_setscheduler(pid
, policy
, param
);
3679 * sys_sched_setparam - set/change the RT priority of a thread
3680 * @pid: the pid in question.
3681 * @param: structure containing the new RT priority.
3683 * Return: 0 on success. An error code otherwise.
3685 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3687 return do_sched_setscheduler(pid
, -1, param
);
3691 * sys_sched_setattr - same as above, but with extended sched_attr
3692 * @pid: the pid in question.
3693 * @uattr: structure containing the extended parameters.
3694 * @flags: for future extension.
3696 SYSCALL_DEFINE3(sched_setattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3697 unsigned int, flags
)
3699 struct sched_attr attr
;
3700 struct task_struct
*p
;
3703 if (!uattr
|| pid
< 0 || flags
)
3706 retval
= sched_copy_attr(uattr
, &attr
);
3710 if (attr
.sched_policy
< 0)
3715 p
= find_process_by_pid(pid
);
3717 retval
= sched_setattr(p
, &attr
);
3724 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3725 * @pid: the pid in question.
3727 * Return: On success, the policy of the thread. Otherwise, a negative error
3730 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3732 struct task_struct
*p
;
3740 p
= find_process_by_pid(pid
);
3742 retval
= security_task_getscheduler(p
);
3745 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3752 * sys_sched_getparam - get the RT priority of a thread
3753 * @pid: the pid in question.
3754 * @param: structure containing the RT priority.
3756 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3759 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3761 struct sched_param lp
= { .sched_priority
= 0 };
3762 struct task_struct
*p
;
3765 if (!param
|| pid
< 0)
3769 p
= find_process_by_pid(pid
);
3774 retval
= security_task_getscheduler(p
);
3778 if (task_has_rt_policy(p
))
3779 lp
.sched_priority
= p
->rt_priority
;
3783 * This one might sleep, we cannot do it with a spinlock held ...
3785 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3794 static int sched_read_attr(struct sched_attr __user
*uattr
,
3795 struct sched_attr
*attr
,
3800 if (!access_ok(VERIFY_WRITE
, uattr
, usize
))
3804 * If we're handed a smaller struct than we know of,
3805 * ensure all the unknown bits are 0 - i.e. old
3806 * user-space does not get uncomplete information.
3808 if (usize
< sizeof(*attr
)) {
3809 unsigned char *addr
;
3812 addr
= (void *)attr
+ usize
;
3813 end
= (void *)attr
+ sizeof(*attr
);
3815 for (; addr
< end
; addr
++) {
3823 ret
= copy_to_user(uattr
, attr
, attr
->size
);
3831 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
3832 * @pid: the pid in question.
3833 * @uattr: structure containing the extended parameters.
3834 * @size: sizeof(attr) for fwd/bwd comp.
3835 * @flags: for future extension.
3837 SYSCALL_DEFINE4(sched_getattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3838 unsigned int, size
, unsigned int, flags
)
3840 struct sched_attr attr
= {
3841 .size
= sizeof(struct sched_attr
),
3843 struct task_struct
*p
;
3846 if (!uattr
|| pid
< 0 || size
> PAGE_SIZE
||
3847 size
< SCHED_ATTR_SIZE_VER0
|| flags
)
3851 p
= find_process_by_pid(pid
);
3856 retval
= security_task_getscheduler(p
);
3860 attr
.sched_policy
= p
->policy
;
3861 if (p
->sched_reset_on_fork
)
3862 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3863 if (task_has_dl_policy(p
))
3864 __getparam_dl(p
, &attr
);
3865 else if (task_has_rt_policy(p
))
3866 attr
.sched_priority
= p
->rt_priority
;
3868 attr
.sched_nice
= task_nice(p
);
3872 retval
= sched_read_attr(uattr
, &attr
, size
);
3880 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
3882 cpumask_var_t cpus_allowed
, new_mask
;
3883 struct task_struct
*p
;
3888 p
= find_process_by_pid(pid
);
3894 /* Prevent p going away */
3898 if (p
->flags
& PF_NO_SETAFFINITY
) {
3902 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
3906 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
3908 goto out_free_cpus_allowed
;
3911 if (!check_same_owner(p
)) {
3913 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
3920 retval
= security_task_setscheduler(p
);
3925 cpuset_cpus_allowed(p
, cpus_allowed
);
3926 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
3929 * Since bandwidth control happens on root_domain basis,
3930 * if admission test is enabled, we only admit -deadline
3931 * tasks allowed to run on all the CPUs in the task's
3935 if (task_has_dl_policy(p
)) {
3936 const struct cpumask
*span
= task_rq(p
)->rd
->span
;
3938 if (dl_bandwidth_enabled() && !cpumask_subset(span
, new_mask
)) {
3945 retval
= set_cpus_allowed_ptr(p
, new_mask
);
3948 cpuset_cpus_allowed(p
, cpus_allowed
);
3949 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
3951 * We must have raced with a concurrent cpuset
3952 * update. Just reset the cpus_allowed to the
3953 * cpuset's cpus_allowed
3955 cpumask_copy(new_mask
, cpus_allowed
);
3960 free_cpumask_var(new_mask
);
3961 out_free_cpus_allowed
:
3962 free_cpumask_var(cpus_allowed
);
3968 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
3969 struct cpumask
*new_mask
)
3971 if (len
< cpumask_size())
3972 cpumask_clear(new_mask
);
3973 else if (len
> cpumask_size())
3974 len
= cpumask_size();
3976 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
3980 * sys_sched_setaffinity - set the cpu affinity of a process
3981 * @pid: pid of the process
3982 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3983 * @user_mask_ptr: user-space pointer to the new cpu mask
3985 * Return: 0 on success. An error code otherwise.
3987 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
3988 unsigned long __user
*, user_mask_ptr
)
3990 cpumask_var_t new_mask
;
3993 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
3996 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
3998 retval
= sched_setaffinity(pid
, new_mask
);
3999 free_cpumask_var(new_mask
);
4003 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4005 struct task_struct
*p
;
4006 unsigned long flags
;
4012 p
= find_process_by_pid(pid
);
4016 retval
= security_task_getscheduler(p
);
4020 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4021 cpumask_and(mask
, &p
->cpus_allowed
, cpu_active_mask
);
4022 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4031 * sys_sched_getaffinity - get the cpu affinity of a process
4032 * @pid: pid of the process
4033 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4034 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4036 * Return: 0 on success. An error code otherwise.
4038 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4039 unsigned long __user
*, user_mask_ptr
)
4044 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4046 if (len
& (sizeof(unsigned long)-1))
4049 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4052 ret
= sched_getaffinity(pid
, mask
);
4054 size_t retlen
= min_t(size_t, len
, cpumask_size());
4056 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4061 free_cpumask_var(mask
);
4067 * sys_sched_yield - yield the current processor to other threads.
4069 * This function yields the current CPU to other tasks. If there are no
4070 * other threads running on this CPU then this function will return.
4074 SYSCALL_DEFINE0(sched_yield
)
4076 struct rq
*rq
= this_rq_lock();
4078 schedstat_inc(rq
, yld_count
);
4079 current
->sched_class
->yield_task(rq
);
4082 * Since we are going to call schedule() anyway, there's
4083 * no need to preempt or enable interrupts:
4085 __release(rq
->lock
);
4086 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4087 do_raw_spin_unlock(&rq
->lock
);
4088 sched_preempt_enable_no_resched();
4095 static void __cond_resched(void)
4097 __preempt_count_add(PREEMPT_ACTIVE
);
4099 __preempt_count_sub(PREEMPT_ACTIVE
);
4102 int __sched
_cond_resched(void)
4104 if (should_resched()) {
4110 EXPORT_SYMBOL(_cond_resched
);
4113 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4114 * call schedule, and on return reacquire the lock.
4116 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4117 * operations here to prevent schedule() from being called twice (once via
4118 * spin_unlock(), once by hand).
4120 int __cond_resched_lock(spinlock_t
*lock
)
4122 int resched
= should_resched();
4125 lockdep_assert_held(lock
);
4127 if (spin_needbreak(lock
) || resched
) {
4138 EXPORT_SYMBOL(__cond_resched_lock
);
4140 int __sched
__cond_resched_softirq(void)
4142 BUG_ON(!in_softirq());
4144 if (should_resched()) {
4152 EXPORT_SYMBOL(__cond_resched_softirq
);
4155 * yield - yield the current processor to other threads.
4157 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4159 * The scheduler is at all times free to pick the calling task as the most
4160 * eligible task to run, if removing the yield() call from your code breaks
4161 * it, its already broken.
4163 * Typical broken usage is:
4168 * where one assumes that yield() will let 'the other' process run that will
4169 * make event true. If the current task is a SCHED_FIFO task that will never
4170 * happen. Never use yield() as a progress guarantee!!
4172 * If you want to use yield() to wait for something, use wait_event().
4173 * If you want to use yield() to be 'nice' for others, use cond_resched().
4174 * If you still want to use yield(), do not!
4176 void __sched
yield(void)
4178 set_current_state(TASK_RUNNING
);
4181 EXPORT_SYMBOL(yield
);
4184 * yield_to - yield the current processor to another thread in
4185 * your thread group, or accelerate that thread toward the
4186 * processor it's on.
4188 * @preempt: whether task preemption is allowed or not
4190 * It's the caller's job to ensure that the target task struct
4191 * can't go away on us before we can do any checks.
4194 * true (>0) if we indeed boosted the target task.
4195 * false (0) if we failed to boost the target.
4196 * -ESRCH if there's no task to yield to.
4198 int __sched
yield_to(struct task_struct
*p
, bool preempt
)
4200 struct task_struct
*curr
= current
;
4201 struct rq
*rq
, *p_rq
;
4202 unsigned long flags
;
4205 local_irq_save(flags
);
4211 * If we're the only runnable task on the rq and target rq also
4212 * has only one task, there's absolutely no point in yielding.
4214 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
4219 double_rq_lock(rq
, p_rq
);
4220 if (task_rq(p
) != p_rq
) {
4221 double_rq_unlock(rq
, p_rq
);
4225 if (!curr
->sched_class
->yield_to_task
)
4228 if (curr
->sched_class
!= p
->sched_class
)
4231 if (task_running(p_rq
, p
) || p
->state
)
4234 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4236 schedstat_inc(rq
, yld_count
);
4238 * Make p's CPU reschedule; pick_next_entity takes care of
4241 if (preempt
&& rq
!= p_rq
)
4242 resched_task(p_rq
->curr
);
4246 double_rq_unlock(rq
, p_rq
);
4248 local_irq_restore(flags
);
4255 EXPORT_SYMBOL_GPL(yield_to
);
4258 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4259 * that process accounting knows that this is a task in IO wait state.
4261 void __sched
io_schedule(void)
4263 struct rq
*rq
= raw_rq();
4265 delayacct_blkio_start();
4266 atomic_inc(&rq
->nr_iowait
);
4267 blk_flush_plug(current
);
4268 current
->in_iowait
= 1;
4270 current
->in_iowait
= 0;
4271 atomic_dec(&rq
->nr_iowait
);
4272 delayacct_blkio_end();
4274 EXPORT_SYMBOL(io_schedule
);
4276 long __sched
io_schedule_timeout(long timeout
)
4278 struct rq
*rq
= raw_rq();
4281 delayacct_blkio_start();
4282 atomic_inc(&rq
->nr_iowait
);
4283 blk_flush_plug(current
);
4284 current
->in_iowait
= 1;
4285 ret
= schedule_timeout(timeout
);
4286 current
->in_iowait
= 0;
4287 atomic_dec(&rq
->nr_iowait
);
4288 delayacct_blkio_end();
4293 * sys_sched_get_priority_max - return maximum RT priority.
4294 * @policy: scheduling class.
4296 * Return: On success, this syscall returns the maximum
4297 * rt_priority that can be used by a given scheduling class.
4298 * On failure, a negative error code is returned.
4300 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4307 ret
= MAX_USER_RT_PRIO
-1;
4309 case SCHED_DEADLINE
:
4320 * sys_sched_get_priority_min - return minimum RT priority.
4321 * @policy: scheduling class.
4323 * Return: On success, this syscall returns the minimum
4324 * rt_priority that can be used by a given scheduling class.
4325 * On failure, a negative error code is returned.
4327 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4336 case SCHED_DEADLINE
:
4346 * sys_sched_rr_get_interval - return the default timeslice of a process.
4347 * @pid: pid of the process.
4348 * @interval: userspace pointer to the timeslice value.
4350 * this syscall writes the default timeslice value of a given process
4351 * into the user-space timespec buffer. A value of '0' means infinity.
4353 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4356 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4357 struct timespec __user
*, interval
)
4359 struct task_struct
*p
;
4360 unsigned int time_slice
;
4361 unsigned long flags
;
4371 p
= find_process_by_pid(pid
);
4375 retval
= security_task_getscheduler(p
);
4379 rq
= task_rq_lock(p
, &flags
);
4381 if (p
->sched_class
->get_rr_interval
)
4382 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4383 task_rq_unlock(rq
, p
, &flags
);
4386 jiffies_to_timespec(time_slice
, &t
);
4387 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4395 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4397 void sched_show_task(struct task_struct
*p
)
4399 unsigned long free
= 0;
4403 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4404 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4405 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4406 #if BITS_PER_LONG == 32
4407 if (state
== TASK_RUNNING
)
4408 printk(KERN_CONT
" running ");
4410 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4412 if (state
== TASK_RUNNING
)
4413 printk(KERN_CONT
" running task ");
4415 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4417 #ifdef CONFIG_DEBUG_STACK_USAGE
4418 free
= stack_not_used(p
);
4421 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4423 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4424 task_pid_nr(p
), ppid
,
4425 (unsigned long)task_thread_info(p
)->flags
);
4427 print_worker_info(KERN_INFO
, p
);
4428 show_stack(p
, NULL
);
4431 void show_state_filter(unsigned long state_filter
)
4433 struct task_struct
*g
, *p
;
4435 #if BITS_PER_LONG == 32
4437 " task PC stack pid father\n");
4440 " task PC stack pid father\n");
4443 do_each_thread(g
, p
) {
4445 * reset the NMI-timeout, listing all files on a slow
4446 * console might take a lot of time:
4448 touch_nmi_watchdog();
4449 if (!state_filter
|| (p
->state
& state_filter
))
4451 } while_each_thread(g
, p
);
4453 touch_all_softlockup_watchdogs();
4455 #ifdef CONFIG_SCHED_DEBUG
4456 sysrq_sched_debug_show();
4460 * Only show locks if all tasks are dumped:
4463 debug_show_all_locks();
4466 void init_idle_bootup_task(struct task_struct
*idle
)
4468 idle
->sched_class
= &idle_sched_class
;
4472 * init_idle - set up an idle thread for a given CPU
4473 * @idle: task in question
4474 * @cpu: cpu the idle task belongs to
4476 * NOTE: this function does not set the idle thread's NEED_RESCHED
4477 * flag, to make booting more robust.
4479 void init_idle(struct task_struct
*idle
, int cpu
)
4481 struct rq
*rq
= cpu_rq(cpu
);
4482 unsigned long flags
;
4484 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4486 __sched_fork(0, idle
);
4487 idle
->state
= TASK_RUNNING
;
4488 idle
->se
.exec_start
= sched_clock();
4490 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4492 * We're having a chicken and egg problem, even though we are
4493 * holding rq->lock, the cpu isn't yet set to this cpu so the
4494 * lockdep check in task_group() will fail.
4496 * Similar case to sched_fork(). / Alternatively we could
4497 * use task_rq_lock() here and obtain the other rq->lock.
4502 __set_task_cpu(idle
, cpu
);
4505 rq
->curr
= rq
->idle
= idle
;
4507 #if defined(CONFIG_SMP)
4510 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4512 /* Set the preempt count _outside_ the spinlocks! */
4513 init_idle_preempt_count(idle
, cpu
);
4516 * The idle tasks have their own, simple scheduling class:
4518 idle
->sched_class
= &idle_sched_class
;
4519 ftrace_graph_init_idle_task(idle
, cpu
);
4520 vtime_init_idle(idle
, cpu
);
4521 #if defined(CONFIG_SMP)
4522 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4527 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4529 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4530 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4532 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4533 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4537 * This is how migration works:
4539 * 1) we invoke migration_cpu_stop() on the target CPU using
4541 * 2) stopper starts to run (implicitly forcing the migrated thread
4543 * 3) it checks whether the migrated task is still in the wrong runqueue.
4544 * 4) if it's in the wrong runqueue then the migration thread removes
4545 * it and puts it into the right queue.
4546 * 5) stopper completes and stop_one_cpu() returns and the migration
4551 * Change a given task's CPU affinity. Migrate the thread to a
4552 * proper CPU and schedule it away if the CPU it's executing on
4553 * is removed from the allowed bitmask.
4555 * NOTE: the caller must have a valid reference to the task, the
4556 * task must not exit() & deallocate itself prematurely. The
4557 * call is not atomic; no spinlocks may be held.
4559 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4561 unsigned long flags
;
4563 unsigned int dest_cpu
;
4566 rq
= task_rq_lock(p
, &flags
);
4568 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4571 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4576 do_set_cpus_allowed(p
, new_mask
);
4578 /* Can the task run on the task's current CPU? If so, we're done */
4579 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4582 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4584 struct migration_arg arg
= { p
, dest_cpu
};
4585 /* Need help from migration thread: drop lock and wait. */
4586 task_rq_unlock(rq
, p
, &flags
);
4587 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4588 tlb_migrate_finish(p
->mm
);
4592 task_rq_unlock(rq
, p
, &flags
);
4596 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4599 * Move (not current) task off this cpu, onto dest cpu. We're doing
4600 * this because either it can't run here any more (set_cpus_allowed()
4601 * away from this CPU, or CPU going down), or because we're
4602 * attempting to rebalance this task on exec (sched_exec).
4604 * So we race with normal scheduler movements, but that's OK, as long
4605 * as the task is no longer on this CPU.
4607 * Returns non-zero if task was successfully migrated.
4609 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4611 struct rq
*rq_dest
, *rq_src
;
4614 if (unlikely(!cpu_active(dest_cpu
)))
4617 rq_src
= cpu_rq(src_cpu
);
4618 rq_dest
= cpu_rq(dest_cpu
);
4620 raw_spin_lock(&p
->pi_lock
);
4621 double_rq_lock(rq_src
, rq_dest
);
4622 /* Already moved. */
4623 if (task_cpu(p
) != src_cpu
)
4625 /* Affinity changed (again). */
4626 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4630 * If we're not on a rq, the next wake-up will ensure we're
4634 dequeue_task(rq_src
, p
, 0);
4635 set_task_cpu(p
, dest_cpu
);
4636 enqueue_task(rq_dest
, p
, 0);
4637 check_preempt_curr(rq_dest
, p
, 0);
4642 double_rq_unlock(rq_src
, rq_dest
);
4643 raw_spin_unlock(&p
->pi_lock
);
4647 #ifdef CONFIG_NUMA_BALANCING
4648 /* Migrate current task p to target_cpu */
4649 int migrate_task_to(struct task_struct
*p
, int target_cpu
)
4651 struct migration_arg arg
= { p
, target_cpu
};
4652 int curr_cpu
= task_cpu(p
);
4654 if (curr_cpu
== target_cpu
)
4657 if (!cpumask_test_cpu(target_cpu
, tsk_cpus_allowed(p
)))
4660 /* TODO: This is not properly updating schedstats */
4662 trace_sched_move_numa(p
, curr_cpu
, target_cpu
);
4663 return stop_one_cpu(curr_cpu
, migration_cpu_stop
, &arg
);
4667 * Requeue a task on a given node and accurately track the number of NUMA
4668 * tasks on the runqueues
4670 void sched_setnuma(struct task_struct
*p
, int nid
)
4673 unsigned long flags
;
4674 bool on_rq
, running
;
4676 rq
= task_rq_lock(p
, &flags
);
4678 running
= task_current(rq
, p
);
4681 dequeue_task(rq
, p
, 0);
4683 p
->sched_class
->put_prev_task(rq
, p
);
4685 p
->numa_preferred_nid
= nid
;
4688 p
->sched_class
->set_curr_task(rq
);
4690 enqueue_task(rq
, p
, 0);
4691 task_rq_unlock(rq
, p
, &flags
);
4696 * migration_cpu_stop - this will be executed by a highprio stopper thread
4697 * and performs thread migration by bumping thread off CPU then
4698 * 'pushing' onto another runqueue.
4700 static int migration_cpu_stop(void *data
)
4702 struct migration_arg
*arg
= data
;
4705 * The original target cpu might have gone down and we might
4706 * be on another cpu but it doesn't matter.
4708 local_irq_disable();
4709 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4714 #ifdef CONFIG_HOTPLUG_CPU
4717 * Ensures that the idle task is using init_mm right before its cpu goes
4720 void idle_task_exit(void)
4722 struct mm_struct
*mm
= current
->active_mm
;
4724 BUG_ON(cpu_online(smp_processor_id()));
4726 if (mm
!= &init_mm
) {
4727 switch_mm(mm
, &init_mm
, current
);
4728 finish_arch_post_lock_switch();
4734 * Since this CPU is going 'away' for a while, fold any nr_active delta
4735 * we might have. Assumes we're called after migrate_tasks() so that the
4736 * nr_active count is stable.
4738 * Also see the comment "Global load-average calculations".
4740 static void calc_load_migrate(struct rq
*rq
)
4742 long delta
= calc_load_fold_active(rq
);
4744 atomic_long_add(delta
, &calc_load_tasks
);
4747 static void put_prev_task_fake(struct rq
*rq
, struct task_struct
*prev
)
4751 static const struct sched_class fake_sched_class
= {
4752 .put_prev_task
= put_prev_task_fake
,
4755 static struct task_struct fake_task
= {
4757 * Avoid pull_{rt,dl}_task()
4759 .prio
= MAX_PRIO
+ 1,
4760 .sched_class
= &fake_sched_class
,
4764 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4765 * try_to_wake_up()->select_task_rq().
4767 * Called with rq->lock held even though we'er in stop_machine() and
4768 * there's no concurrency possible, we hold the required locks anyway
4769 * because of lock validation efforts.
4771 static void migrate_tasks(unsigned int dead_cpu
)
4773 struct rq
*rq
= cpu_rq(dead_cpu
);
4774 struct task_struct
*next
, *stop
= rq
->stop
;
4778 * Fudge the rq selection such that the below task selection loop
4779 * doesn't get stuck on the currently eligible stop task.
4781 * We're currently inside stop_machine() and the rq is either stuck
4782 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4783 * either way we should never end up calling schedule() until we're
4789 * put_prev_task() and pick_next_task() sched
4790 * class method both need to have an up-to-date
4791 * value of rq->clock[_task]
4793 update_rq_clock(rq
);
4797 * There's this thread running, bail when that's the only
4800 if (rq
->nr_running
== 1)
4803 next
= pick_next_task(rq
, &fake_task
);
4805 next
->sched_class
->put_prev_task(rq
, next
);
4807 /* Find suitable destination for @next, with force if needed. */
4808 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
4809 raw_spin_unlock(&rq
->lock
);
4811 __migrate_task(next
, dead_cpu
, dest_cpu
);
4813 raw_spin_lock(&rq
->lock
);
4819 #endif /* CONFIG_HOTPLUG_CPU */
4821 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4823 static struct ctl_table sd_ctl_dir
[] = {
4825 .procname
= "sched_domain",
4831 static struct ctl_table sd_ctl_root
[] = {
4833 .procname
= "kernel",
4835 .child
= sd_ctl_dir
,
4840 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
4842 struct ctl_table
*entry
=
4843 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
4848 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
4850 struct ctl_table
*entry
;
4853 * In the intermediate directories, both the child directory and
4854 * procname are dynamically allocated and could fail but the mode
4855 * will always be set. In the lowest directory the names are
4856 * static strings and all have proc handlers.
4858 for (entry
= *tablep
; entry
->mode
; entry
++) {
4860 sd_free_ctl_entry(&entry
->child
);
4861 if (entry
->proc_handler
== NULL
)
4862 kfree(entry
->procname
);
4869 static int min_load_idx
= 0;
4870 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
4873 set_table_entry(struct ctl_table
*entry
,
4874 const char *procname
, void *data
, int maxlen
,
4875 umode_t mode
, proc_handler
*proc_handler
,
4878 entry
->procname
= procname
;
4880 entry
->maxlen
= maxlen
;
4882 entry
->proc_handler
= proc_handler
;
4885 entry
->extra1
= &min_load_idx
;
4886 entry
->extra2
= &max_load_idx
;
4890 static struct ctl_table
*
4891 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
4893 struct ctl_table
*table
= sd_alloc_ctl_entry(14);
4898 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
4899 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4900 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
4901 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4902 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
4903 sizeof(int), 0644, proc_dointvec_minmax
, true);
4904 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
4905 sizeof(int), 0644, proc_dointvec_minmax
, true);
4906 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
4907 sizeof(int), 0644, proc_dointvec_minmax
, true);
4908 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
4909 sizeof(int), 0644, proc_dointvec_minmax
, true);
4910 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
4911 sizeof(int), 0644, proc_dointvec_minmax
, true);
4912 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
4913 sizeof(int), 0644, proc_dointvec_minmax
, false);
4914 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
4915 sizeof(int), 0644, proc_dointvec_minmax
, false);
4916 set_table_entry(&table
[9], "cache_nice_tries",
4917 &sd
->cache_nice_tries
,
4918 sizeof(int), 0644, proc_dointvec_minmax
, false);
4919 set_table_entry(&table
[10], "flags", &sd
->flags
,
4920 sizeof(int), 0644, proc_dointvec_minmax
, false);
4921 set_table_entry(&table
[11], "max_newidle_lb_cost",
4922 &sd
->max_newidle_lb_cost
,
4923 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4924 set_table_entry(&table
[12], "name", sd
->name
,
4925 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
4926 /* &table[13] is terminator */
4931 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
4933 struct ctl_table
*entry
, *table
;
4934 struct sched_domain
*sd
;
4935 int domain_num
= 0, i
;
4938 for_each_domain(cpu
, sd
)
4940 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
4945 for_each_domain(cpu
, sd
) {
4946 snprintf(buf
, 32, "domain%d", i
);
4947 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4949 entry
->child
= sd_alloc_ctl_domain_table(sd
);
4956 static struct ctl_table_header
*sd_sysctl_header
;
4957 static void register_sched_domain_sysctl(void)
4959 int i
, cpu_num
= num_possible_cpus();
4960 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
4963 WARN_ON(sd_ctl_dir
[0].child
);
4964 sd_ctl_dir
[0].child
= entry
;
4969 for_each_possible_cpu(i
) {
4970 snprintf(buf
, 32, "cpu%d", i
);
4971 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4973 entry
->child
= sd_alloc_ctl_cpu_table(i
);
4977 WARN_ON(sd_sysctl_header
);
4978 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
4981 /* may be called multiple times per register */
4982 static void unregister_sched_domain_sysctl(void)
4984 if (sd_sysctl_header
)
4985 unregister_sysctl_table(sd_sysctl_header
);
4986 sd_sysctl_header
= NULL
;
4987 if (sd_ctl_dir
[0].child
)
4988 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
4991 static void register_sched_domain_sysctl(void)
4994 static void unregister_sched_domain_sysctl(void)
4999 static void set_rq_online(struct rq
*rq
)
5002 const struct sched_class
*class;
5004 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5007 for_each_class(class) {
5008 if (class->rq_online
)
5009 class->rq_online(rq
);
5014 static void set_rq_offline(struct rq
*rq
)
5017 const struct sched_class
*class;
5019 for_each_class(class) {
5020 if (class->rq_offline
)
5021 class->rq_offline(rq
);
5024 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5030 * migration_call - callback that gets triggered when a CPU is added.
5031 * Here we can start up the necessary migration thread for the new CPU.
5034 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5036 int cpu
= (long)hcpu
;
5037 unsigned long flags
;
5038 struct rq
*rq
= cpu_rq(cpu
);
5040 switch (action
& ~CPU_TASKS_FROZEN
) {
5042 case CPU_UP_PREPARE
:
5043 rq
->calc_load_update
= calc_load_update
;
5047 /* Update our root-domain */
5048 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5050 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5054 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5057 #ifdef CONFIG_HOTPLUG_CPU
5059 sched_ttwu_pending();
5060 /* Update our root-domain */
5061 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5063 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5067 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5068 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5072 calc_load_migrate(rq
);
5077 update_max_interval();
5083 * Register at high priority so that task migration (migrate_all_tasks)
5084 * happens before everything else. This has to be lower priority than
5085 * the notifier in the perf_event subsystem, though.
5087 static struct notifier_block migration_notifier
= {
5088 .notifier_call
= migration_call
,
5089 .priority
= CPU_PRI_MIGRATION
,
5092 static void __cpuinit
set_cpu_rq_start_time(void)
5094 int cpu
= smp_processor_id();
5095 struct rq
*rq
= cpu_rq(cpu
);
5096 rq
->age_stamp
= sched_clock_cpu(cpu
);
5099 static int sched_cpu_active(struct notifier_block
*nfb
,
5100 unsigned long action
, void *hcpu
)
5102 switch (action
& ~CPU_TASKS_FROZEN
) {
5104 set_cpu_rq_start_time();
5106 case CPU_DOWN_FAILED
:
5107 set_cpu_active((long)hcpu
, true);
5114 static int sched_cpu_inactive(struct notifier_block
*nfb
,
5115 unsigned long action
, void *hcpu
)
5117 unsigned long flags
;
5118 long cpu
= (long)hcpu
;
5120 switch (action
& ~CPU_TASKS_FROZEN
) {
5121 case CPU_DOWN_PREPARE
:
5122 set_cpu_active(cpu
, false);
5124 /* explicitly allow suspend */
5125 if (!(action
& CPU_TASKS_FROZEN
)) {
5126 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
5130 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
5131 cpus
= dl_bw_cpus(cpu
);
5132 overflow
= __dl_overflow(dl_b
, cpus
, 0, 0);
5133 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
5136 return notifier_from_errno(-EBUSY
);
5144 static int __init
migration_init(void)
5146 void *cpu
= (void *)(long)smp_processor_id();
5149 /* Initialize migration for the boot CPU */
5150 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5151 BUG_ON(err
== NOTIFY_BAD
);
5152 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5153 register_cpu_notifier(&migration_notifier
);
5155 /* Register cpu active notifiers */
5156 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5157 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5161 early_initcall(migration_init
);
5166 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5168 #ifdef CONFIG_SCHED_DEBUG
5170 static __read_mostly
int sched_debug_enabled
;
5172 static int __init
sched_debug_setup(char *str
)
5174 sched_debug_enabled
= 1;
5178 early_param("sched_debug", sched_debug_setup
);
5180 static inline bool sched_debug(void)
5182 return sched_debug_enabled
;
5185 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5186 struct cpumask
*groupmask
)
5188 struct sched_group
*group
= sd
->groups
;
5191 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5192 cpumask_clear(groupmask
);
5194 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5196 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5197 printk("does not load-balance\n");
5199 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5204 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5206 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5207 printk(KERN_ERR
"ERROR: domain->span does not contain "
5210 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5211 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5215 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5219 printk(KERN_ERR
"ERROR: group is NULL\n");
5224 * Even though we initialize ->capacity to something semi-sane,
5225 * we leave capacity_orig unset. This allows us to detect if
5226 * domain iteration is still funny without causing /0 traps.
5228 if (!group
->sgc
->capacity_orig
) {
5229 printk(KERN_CONT
"\n");
5230 printk(KERN_ERR
"ERROR: domain->cpu_capacity not set\n");
5234 if (!cpumask_weight(sched_group_cpus(group
))) {
5235 printk(KERN_CONT
"\n");
5236 printk(KERN_ERR
"ERROR: empty group\n");
5240 if (!(sd
->flags
& SD_OVERLAP
) &&
5241 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5242 printk(KERN_CONT
"\n");
5243 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5247 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5249 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
5251 printk(KERN_CONT
" %s", str
);
5252 if (group
->sgc
->capacity
!= SCHED_POWER_SCALE
) {
5253 printk(KERN_CONT
" (cpu_capacity = %d)",
5254 group
->sgc
->capacity
);
5257 group
= group
->next
;
5258 } while (group
!= sd
->groups
);
5259 printk(KERN_CONT
"\n");
5261 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5262 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5265 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5266 printk(KERN_ERR
"ERROR: parent span is not a superset "
5267 "of domain->span\n");
5271 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5275 if (!sched_debug_enabled
)
5279 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5283 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5286 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5294 #else /* !CONFIG_SCHED_DEBUG */
5295 # define sched_domain_debug(sd, cpu) do { } while (0)
5296 static inline bool sched_debug(void)
5300 #endif /* CONFIG_SCHED_DEBUG */
5302 static int sd_degenerate(struct sched_domain
*sd
)
5304 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5307 /* Following flags need at least 2 groups */
5308 if (sd
->flags
& (SD_LOAD_BALANCE
|
5309 SD_BALANCE_NEWIDLE
|
5313 SD_SHARE_PKG_RESOURCES
|
5314 SD_SHARE_POWERDOMAIN
)) {
5315 if (sd
->groups
!= sd
->groups
->next
)
5319 /* Following flags don't use groups */
5320 if (sd
->flags
& (SD_WAKE_AFFINE
))
5327 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5329 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5331 if (sd_degenerate(parent
))
5334 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5337 /* Flags needing groups don't count if only 1 group in parent */
5338 if (parent
->groups
== parent
->groups
->next
) {
5339 pflags
&= ~(SD_LOAD_BALANCE
|
5340 SD_BALANCE_NEWIDLE
|
5344 SD_SHARE_PKG_RESOURCES
|
5346 SD_SHARE_POWERDOMAIN
);
5347 if (nr_node_ids
== 1)
5348 pflags
&= ~SD_SERIALIZE
;
5350 if (~cflags
& pflags
)
5356 static void free_rootdomain(struct rcu_head
*rcu
)
5358 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5360 cpupri_cleanup(&rd
->cpupri
);
5361 cpudl_cleanup(&rd
->cpudl
);
5362 free_cpumask_var(rd
->dlo_mask
);
5363 free_cpumask_var(rd
->rto_mask
);
5364 free_cpumask_var(rd
->online
);
5365 free_cpumask_var(rd
->span
);
5369 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5371 struct root_domain
*old_rd
= NULL
;
5372 unsigned long flags
;
5374 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5379 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5382 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5385 * If we dont want to free the old_rd yet then
5386 * set old_rd to NULL to skip the freeing later
5389 if (!atomic_dec_and_test(&old_rd
->refcount
))
5393 atomic_inc(&rd
->refcount
);
5396 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5397 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5400 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5403 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5406 static int init_rootdomain(struct root_domain
*rd
)
5408 memset(rd
, 0, sizeof(*rd
));
5410 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5412 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5414 if (!alloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
5416 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5419 init_dl_bw(&rd
->dl_bw
);
5420 if (cpudl_init(&rd
->cpudl
) != 0)
5423 if (cpupri_init(&rd
->cpupri
) != 0)
5428 free_cpumask_var(rd
->rto_mask
);
5430 free_cpumask_var(rd
->dlo_mask
);
5432 free_cpumask_var(rd
->online
);
5434 free_cpumask_var(rd
->span
);
5440 * By default the system creates a single root-domain with all cpus as
5441 * members (mimicking the global state we have today).
5443 struct root_domain def_root_domain
;
5445 static void init_defrootdomain(void)
5447 init_rootdomain(&def_root_domain
);
5449 atomic_set(&def_root_domain
.refcount
, 1);
5452 static struct root_domain
*alloc_rootdomain(void)
5454 struct root_domain
*rd
;
5456 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5460 if (init_rootdomain(rd
) != 0) {
5468 static void free_sched_groups(struct sched_group
*sg
, int free_sgc
)
5470 struct sched_group
*tmp
, *first
;
5479 if (free_sgc
&& atomic_dec_and_test(&sg
->sgc
->ref
))
5484 } while (sg
!= first
);
5487 static void free_sched_domain(struct rcu_head
*rcu
)
5489 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5492 * If its an overlapping domain it has private groups, iterate and
5495 if (sd
->flags
& SD_OVERLAP
) {
5496 free_sched_groups(sd
->groups
, 1);
5497 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5498 kfree(sd
->groups
->sgc
);
5504 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5506 call_rcu(&sd
->rcu
, free_sched_domain
);
5509 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5511 for (; sd
; sd
= sd
->parent
)
5512 destroy_sched_domain(sd
, cpu
);
5516 * Keep a special pointer to the highest sched_domain that has
5517 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5518 * allows us to avoid some pointer chasing select_idle_sibling().
5520 * Also keep a unique ID per domain (we use the first cpu number in
5521 * the cpumask of the domain), this allows us to quickly tell if
5522 * two cpus are in the same cache domain, see cpus_share_cache().
5524 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5525 DEFINE_PER_CPU(int, sd_llc_size
);
5526 DEFINE_PER_CPU(int, sd_llc_id
);
5527 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
5528 DEFINE_PER_CPU(struct sched_domain
*, sd_busy
);
5529 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
5531 static void update_top_cache_domain(int cpu
)
5533 struct sched_domain
*sd
;
5534 struct sched_domain
*busy_sd
= NULL
;
5538 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5540 id
= cpumask_first(sched_domain_span(sd
));
5541 size
= cpumask_weight(sched_domain_span(sd
));
5542 busy_sd
= sd
->parent
; /* sd_busy */
5544 rcu_assign_pointer(per_cpu(sd_busy
, cpu
), busy_sd
);
5546 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5547 per_cpu(sd_llc_size
, cpu
) = size
;
5548 per_cpu(sd_llc_id
, cpu
) = id
;
5550 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
5551 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
5553 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
5554 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
5558 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5559 * hold the hotplug lock.
5562 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5564 struct rq
*rq
= cpu_rq(cpu
);
5565 struct sched_domain
*tmp
;
5567 /* Remove the sched domains which do not contribute to scheduling. */
5568 for (tmp
= sd
; tmp
; ) {
5569 struct sched_domain
*parent
= tmp
->parent
;
5573 if (sd_parent_degenerate(tmp
, parent
)) {
5574 tmp
->parent
= parent
->parent
;
5576 parent
->parent
->child
= tmp
;
5578 * Transfer SD_PREFER_SIBLING down in case of a
5579 * degenerate parent; the spans match for this
5580 * so the property transfers.
5582 if (parent
->flags
& SD_PREFER_SIBLING
)
5583 tmp
->flags
|= SD_PREFER_SIBLING
;
5584 destroy_sched_domain(parent
, cpu
);
5589 if (sd
&& sd_degenerate(sd
)) {
5592 destroy_sched_domain(tmp
, cpu
);
5597 sched_domain_debug(sd
, cpu
);
5599 rq_attach_root(rq
, rd
);
5601 rcu_assign_pointer(rq
->sd
, sd
);
5602 destroy_sched_domains(tmp
, cpu
);
5604 update_top_cache_domain(cpu
);
5607 /* cpus with isolated domains */
5608 static cpumask_var_t cpu_isolated_map
;
5610 /* Setup the mask of cpus configured for isolated domains */
5611 static int __init
isolated_cpu_setup(char *str
)
5613 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5614 cpulist_parse(str
, cpu_isolated_map
);
5618 __setup("isolcpus=", isolated_cpu_setup
);
5621 struct sched_domain
** __percpu sd
;
5622 struct root_domain
*rd
;
5633 * Build an iteration mask that can exclude certain CPUs from the upwards
5636 * Asymmetric node setups can result in situations where the domain tree is of
5637 * unequal depth, make sure to skip domains that already cover the entire
5640 * In that case build_sched_domains() will have terminated the iteration early
5641 * and our sibling sd spans will be empty. Domains should always include the
5642 * cpu they're built on, so check that.
5645 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5647 const struct cpumask
*span
= sched_domain_span(sd
);
5648 struct sd_data
*sdd
= sd
->private;
5649 struct sched_domain
*sibling
;
5652 for_each_cpu(i
, span
) {
5653 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5654 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5657 cpumask_set_cpu(i
, sched_group_mask(sg
));
5662 * Return the canonical balance cpu for this group, this is the first cpu
5663 * of this group that's also in the iteration mask.
5665 int group_balance_cpu(struct sched_group
*sg
)
5667 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5671 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5673 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5674 const struct cpumask
*span
= sched_domain_span(sd
);
5675 struct cpumask
*covered
= sched_domains_tmpmask
;
5676 struct sd_data
*sdd
= sd
->private;
5677 struct sched_domain
*child
;
5680 cpumask_clear(covered
);
5682 for_each_cpu(i
, span
) {
5683 struct cpumask
*sg_span
;
5685 if (cpumask_test_cpu(i
, covered
))
5688 child
= *per_cpu_ptr(sdd
->sd
, i
);
5690 /* See the comment near build_group_mask(). */
5691 if (!cpumask_test_cpu(i
, sched_domain_span(child
)))
5694 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5695 GFP_KERNEL
, cpu_to_node(cpu
));
5700 sg_span
= sched_group_cpus(sg
);
5702 child
= child
->child
;
5703 cpumask_copy(sg_span
, sched_domain_span(child
));
5705 cpumask_set_cpu(i
, sg_span
);
5707 cpumask_or(covered
, covered
, sg_span
);
5709 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, i
);
5710 if (atomic_inc_return(&sg
->sgc
->ref
) == 1)
5711 build_group_mask(sd
, sg
);
5714 * Initialize sgc->capacity such that even if we mess up the
5715 * domains and no possible iteration will get us here, we won't
5718 sg
->sgc
->capacity
= SCHED_POWER_SCALE
* cpumask_weight(sg_span
);
5719 sg
->sgc
->capacity_orig
= sg
->sgc
->capacity
;
5722 * Make sure the first group of this domain contains the
5723 * canonical balance cpu. Otherwise the sched_domain iteration
5724 * breaks. See update_sg_lb_stats().
5726 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5727 group_balance_cpu(sg
) == cpu
)
5737 sd
->groups
= groups
;
5742 free_sched_groups(first
, 0);
5747 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5749 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5750 struct sched_domain
*child
= sd
->child
;
5753 cpu
= cpumask_first(sched_domain_span(child
));
5756 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5757 (*sg
)->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
5758 atomic_set(&(*sg
)->sgc
->ref
, 1); /* for claim_allocations */
5765 * build_sched_groups will build a circular linked list of the groups
5766 * covered by the given span, and will set each group's ->cpumask correctly,
5767 * and ->cpu_power to 0.
5769 * Assumes the sched_domain tree is fully constructed
5772 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5774 struct sched_group
*first
= NULL
, *last
= NULL
;
5775 struct sd_data
*sdd
= sd
->private;
5776 const struct cpumask
*span
= sched_domain_span(sd
);
5777 struct cpumask
*covered
;
5780 get_group(cpu
, sdd
, &sd
->groups
);
5781 atomic_inc(&sd
->groups
->ref
);
5783 if (cpu
!= cpumask_first(span
))
5786 lockdep_assert_held(&sched_domains_mutex
);
5787 covered
= sched_domains_tmpmask
;
5789 cpumask_clear(covered
);
5791 for_each_cpu(i
, span
) {
5792 struct sched_group
*sg
;
5795 if (cpumask_test_cpu(i
, covered
))
5798 group
= get_group(i
, sdd
, &sg
);
5799 cpumask_setall(sched_group_mask(sg
));
5801 for_each_cpu(j
, span
) {
5802 if (get_group(j
, sdd
, NULL
) != group
)
5805 cpumask_set_cpu(j
, covered
);
5806 cpumask_set_cpu(j
, sched_group_cpus(sg
));
5821 * Initialize sched groups cpu_capacity.
5823 * cpu_capacity indicates the capacity of sched group, which is used while
5824 * distributing the load between different sched groups in a sched domain.
5825 * Typically cpu_capacity for all the groups in a sched domain will be same
5826 * unless there are asymmetries in the topology. If there are asymmetries,
5827 * group having more cpu_capacity will pickup more load compared to the
5828 * group having less cpu_capacity.
5830 static void init_sched_groups_capacity(int cpu
, struct sched_domain
*sd
)
5832 struct sched_group
*sg
= sd
->groups
;
5837 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
5839 } while (sg
!= sd
->groups
);
5841 if (cpu
!= group_balance_cpu(sg
))
5844 update_group_capacity(sd
, cpu
);
5845 atomic_set(&sg
->sgc
->nr_busy_cpus
, sg
->group_weight
);
5849 * Initializers for schedule domains
5850 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5853 static int default_relax_domain_level
= -1;
5854 int sched_domain_level_max
;
5856 static int __init
setup_relax_domain_level(char *str
)
5858 if (kstrtoint(str
, 0, &default_relax_domain_level
))
5859 pr_warn("Unable to set relax_domain_level\n");
5863 __setup("relax_domain_level=", setup_relax_domain_level
);
5865 static void set_domain_attribute(struct sched_domain
*sd
,
5866 struct sched_domain_attr
*attr
)
5870 if (!attr
|| attr
->relax_domain_level
< 0) {
5871 if (default_relax_domain_level
< 0)
5874 request
= default_relax_domain_level
;
5876 request
= attr
->relax_domain_level
;
5877 if (request
< sd
->level
) {
5878 /* turn off idle balance on this domain */
5879 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5881 /* turn on idle balance on this domain */
5882 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5886 static void __sdt_free(const struct cpumask
*cpu_map
);
5887 static int __sdt_alloc(const struct cpumask
*cpu_map
);
5889 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
5890 const struct cpumask
*cpu_map
)
5894 if (!atomic_read(&d
->rd
->refcount
))
5895 free_rootdomain(&d
->rd
->rcu
); /* fall through */
5897 free_percpu(d
->sd
); /* fall through */
5899 __sdt_free(cpu_map
); /* fall through */
5905 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
5906 const struct cpumask
*cpu_map
)
5908 memset(d
, 0, sizeof(*d
));
5910 if (__sdt_alloc(cpu_map
))
5911 return sa_sd_storage
;
5912 d
->sd
= alloc_percpu(struct sched_domain
*);
5914 return sa_sd_storage
;
5915 d
->rd
= alloc_rootdomain();
5918 return sa_rootdomain
;
5922 * NULL the sd_data elements we've used to build the sched_domain and
5923 * sched_group structure so that the subsequent __free_domain_allocs()
5924 * will not free the data we're using.
5926 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
5928 struct sd_data
*sdd
= sd
->private;
5930 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
5931 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
5933 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
5934 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
5936 if (atomic_read(&(*per_cpu_ptr(sdd
->sgc
, cpu
))->ref
))
5937 *per_cpu_ptr(sdd
->sgc
, cpu
) = NULL
;
5941 static int sched_domains_numa_levels
;
5942 static int *sched_domains_numa_distance
;
5943 static struct cpumask
***sched_domains_numa_masks
;
5944 static int sched_domains_curr_level
;
5948 * SD_flags allowed in topology descriptions.
5950 * SD_SHARE_CPUPOWER - describes SMT topologies
5951 * SD_SHARE_PKG_RESOURCES - describes shared caches
5952 * SD_NUMA - describes NUMA topologies
5953 * SD_SHARE_POWERDOMAIN - describes shared power domain
5956 * SD_ASYM_PACKING - describes SMT quirks
5958 #define TOPOLOGY_SD_FLAGS \
5959 (SD_SHARE_CPUPOWER | \
5960 SD_SHARE_PKG_RESOURCES | \
5963 SD_SHARE_POWERDOMAIN)
5965 static struct sched_domain
*
5966 sd_init(struct sched_domain_topology_level
*tl
, int cpu
)
5968 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
5969 int sd_weight
, sd_flags
= 0;
5973 * Ugly hack to pass state to sd_numa_mask()...
5975 sched_domains_curr_level
= tl
->numa_level
;
5978 sd_weight
= cpumask_weight(tl
->mask(cpu
));
5981 sd_flags
= (*tl
->sd_flags
)();
5982 if (WARN_ONCE(sd_flags
& ~TOPOLOGY_SD_FLAGS
,
5983 "wrong sd_flags in topology description\n"))
5984 sd_flags
&= ~TOPOLOGY_SD_FLAGS
;
5986 *sd
= (struct sched_domain
){
5987 .min_interval
= sd_weight
,
5988 .max_interval
= 2*sd_weight
,
5990 .imbalance_pct
= 125,
5992 .cache_nice_tries
= 0,
5999 .flags
= 1*SD_LOAD_BALANCE
6000 | 1*SD_BALANCE_NEWIDLE
6005 | 0*SD_SHARE_CPUPOWER
6006 | 0*SD_SHARE_PKG_RESOURCES
6008 | 0*SD_PREFER_SIBLING
6013 .last_balance
= jiffies
,
6014 .balance_interval
= sd_weight
,
6016 .max_newidle_lb_cost
= 0,
6017 .next_decay_max_lb_cost
= jiffies
,
6018 #ifdef CONFIG_SCHED_DEBUG
6024 * Convert topological properties into behaviour.
6027 if (sd
->flags
& SD_SHARE_CPUPOWER
) {
6028 sd
->imbalance_pct
= 110;
6029 sd
->smt_gain
= 1178; /* ~15% */
6031 } else if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
6032 sd
->imbalance_pct
= 117;
6033 sd
->cache_nice_tries
= 1;
6037 } else if (sd
->flags
& SD_NUMA
) {
6038 sd
->cache_nice_tries
= 2;
6042 sd
->flags
|= SD_SERIALIZE
;
6043 if (sched_domains_numa_distance
[tl
->numa_level
] > RECLAIM_DISTANCE
) {
6044 sd
->flags
&= ~(SD_BALANCE_EXEC
|
6051 sd
->flags
|= SD_PREFER_SIBLING
;
6052 sd
->cache_nice_tries
= 1;
6057 sd
->private = &tl
->data
;
6063 * Topology list, bottom-up.
6065 static struct sched_domain_topology_level default_topology
[] = {
6066 #ifdef CONFIG_SCHED_SMT
6067 { cpu_smt_mask
, cpu_smt_flags
, SD_INIT_NAME(SMT
) },
6069 #ifdef CONFIG_SCHED_MC
6070 { cpu_coregroup_mask
, cpu_core_flags
, SD_INIT_NAME(MC
) },
6072 { cpu_cpu_mask
, SD_INIT_NAME(DIE
) },
6076 struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6078 #define for_each_sd_topology(tl) \
6079 for (tl = sched_domain_topology; tl->mask; tl++)
6081 void set_sched_topology(struct sched_domain_topology_level
*tl
)
6083 sched_domain_topology
= tl
;
6088 static const struct cpumask
*sd_numa_mask(int cpu
)
6090 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6093 static void sched_numa_warn(const char *str
)
6095 static int done
= false;
6103 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6105 for (i
= 0; i
< nr_node_ids
; i
++) {
6106 printk(KERN_WARNING
" ");
6107 for (j
= 0; j
< nr_node_ids
; j
++)
6108 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6109 printk(KERN_CONT
"\n");
6111 printk(KERN_WARNING
"\n");
6114 static bool find_numa_distance(int distance
)
6118 if (distance
== node_distance(0, 0))
6121 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6122 if (sched_domains_numa_distance
[i
] == distance
)
6129 static void sched_init_numa(void)
6131 int next_distance
, curr_distance
= node_distance(0, 0);
6132 struct sched_domain_topology_level
*tl
;
6136 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6137 if (!sched_domains_numa_distance
)
6141 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6142 * unique distances in the node_distance() table.
6144 * Assumes node_distance(0,j) includes all distances in
6145 * node_distance(i,j) in order to avoid cubic time.
6147 next_distance
= curr_distance
;
6148 for (i
= 0; i
< nr_node_ids
; i
++) {
6149 for (j
= 0; j
< nr_node_ids
; j
++) {
6150 for (k
= 0; k
< nr_node_ids
; k
++) {
6151 int distance
= node_distance(i
, k
);
6153 if (distance
> curr_distance
&&
6154 (distance
< next_distance
||
6155 next_distance
== curr_distance
))
6156 next_distance
= distance
;
6159 * While not a strong assumption it would be nice to know
6160 * about cases where if node A is connected to B, B is not
6161 * equally connected to A.
6163 if (sched_debug() && node_distance(k
, i
) != distance
)
6164 sched_numa_warn("Node-distance not symmetric");
6166 if (sched_debug() && i
&& !find_numa_distance(distance
))
6167 sched_numa_warn("Node-0 not representative");
6169 if (next_distance
!= curr_distance
) {
6170 sched_domains_numa_distance
[level
++] = next_distance
;
6171 sched_domains_numa_levels
= level
;
6172 curr_distance
= next_distance
;
6177 * In case of sched_debug() we verify the above assumption.
6183 * 'level' contains the number of unique distances, excluding the
6184 * identity distance node_distance(i,i).
6186 * The sched_domains_numa_distance[] array includes the actual distance
6191 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6192 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6193 * the array will contain less then 'level' members. This could be
6194 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6195 * in other functions.
6197 * We reset it to 'level' at the end of this function.
6199 sched_domains_numa_levels
= 0;
6201 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6202 if (!sched_domains_numa_masks
)
6206 * Now for each level, construct a mask per node which contains all
6207 * cpus of nodes that are that many hops away from us.
6209 for (i
= 0; i
< level
; i
++) {
6210 sched_domains_numa_masks
[i
] =
6211 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6212 if (!sched_domains_numa_masks
[i
])
6215 for (j
= 0; j
< nr_node_ids
; j
++) {
6216 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6220 sched_domains_numa_masks
[i
][j
] = mask
;
6222 for (k
= 0; k
< nr_node_ids
; k
++) {
6223 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6226 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6231 /* Compute default topology size */
6232 for (i
= 0; sched_domain_topology
[i
].mask
; i
++);
6234 tl
= kzalloc((i
+ level
+ 1) *
6235 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6240 * Copy the default topology bits..
6242 for (i
= 0; sched_domain_topology
[i
].mask
; i
++)
6243 tl
[i
] = sched_domain_topology
[i
];
6246 * .. and append 'j' levels of NUMA goodness.
6248 for (j
= 0; j
< level
; i
++, j
++) {
6249 tl
[i
] = (struct sched_domain_topology_level
){
6250 .mask
= sd_numa_mask
,
6251 .sd_flags
= cpu_numa_flags
,
6252 .flags
= SDTL_OVERLAP
,
6258 sched_domain_topology
= tl
;
6260 sched_domains_numa_levels
= level
;
6263 static void sched_domains_numa_masks_set(int cpu
)
6266 int node
= cpu_to_node(cpu
);
6268 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6269 for (j
= 0; j
< nr_node_ids
; j
++) {
6270 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6271 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6276 static void sched_domains_numa_masks_clear(int cpu
)
6279 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6280 for (j
= 0; j
< nr_node_ids
; j
++)
6281 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6286 * Update sched_domains_numa_masks[level][node] array when new cpus
6289 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6290 unsigned long action
,
6293 int cpu
= (long)hcpu
;
6295 switch (action
& ~CPU_TASKS_FROZEN
) {
6297 sched_domains_numa_masks_set(cpu
);
6301 sched_domains_numa_masks_clear(cpu
);
6311 static inline void sched_init_numa(void)
6315 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6316 unsigned long action
,
6321 #endif /* CONFIG_NUMA */
6323 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6325 struct sched_domain_topology_level
*tl
;
6328 for_each_sd_topology(tl
) {
6329 struct sd_data
*sdd
= &tl
->data
;
6331 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6335 sdd
->sg
= alloc_percpu(struct sched_group
*);
6339 sdd
->sgc
= alloc_percpu(struct sched_group_capacity
*);
6343 for_each_cpu(j
, cpu_map
) {
6344 struct sched_domain
*sd
;
6345 struct sched_group
*sg
;
6346 struct sched_group_capacity
*sgc
;
6348 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6349 GFP_KERNEL
, cpu_to_node(j
));
6353 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6355 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6356 GFP_KERNEL
, cpu_to_node(j
));
6362 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6364 sgc
= kzalloc_node(sizeof(struct sched_group_capacity
) + cpumask_size(),
6365 GFP_KERNEL
, cpu_to_node(j
));
6369 *per_cpu_ptr(sdd
->sgc
, j
) = sgc
;
6376 static void __sdt_free(const struct cpumask
*cpu_map
)
6378 struct sched_domain_topology_level
*tl
;
6381 for_each_sd_topology(tl
) {
6382 struct sd_data
*sdd
= &tl
->data
;
6384 for_each_cpu(j
, cpu_map
) {
6385 struct sched_domain
*sd
;
6388 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6389 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6390 free_sched_groups(sd
->groups
, 0);
6391 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6395 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6397 kfree(*per_cpu_ptr(sdd
->sgc
, j
));
6399 free_percpu(sdd
->sd
);
6401 free_percpu(sdd
->sg
);
6403 free_percpu(sdd
->sgc
);
6408 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6409 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6410 struct sched_domain
*child
, int cpu
)
6412 struct sched_domain
*sd
= sd_init(tl
, cpu
);
6416 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6418 sd
->level
= child
->level
+ 1;
6419 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6423 set_domain_attribute(sd
, attr
);
6429 * Build sched domains for a given set of cpus and attach the sched domains
6430 * to the individual cpus
6432 static int build_sched_domains(const struct cpumask
*cpu_map
,
6433 struct sched_domain_attr
*attr
)
6435 enum s_alloc alloc_state
;
6436 struct sched_domain
*sd
;
6438 int i
, ret
= -ENOMEM
;
6440 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6441 if (alloc_state
!= sa_rootdomain
)
6444 /* Set up domains for cpus specified by the cpu_map. */
6445 for_each_cpu(i
, cpu_map
) {
6446 struct sched_domain_topology_level
*tl
;
6449 for_each_sd_topology(tl
) {
6450 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6451 if (tl
== sched_domain_topology
)
6452 *per_cpu_ptr(d
.sd
, i
) = sd
;
6453 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6454 sd
->flags
|= SD_OVERLAP
;
6455 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6460 /* Build the groups for the domains */
6461 for_each_cpu(i
, cpu_map
) {
6462 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6463 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6464 if (sd
->flags
& SD_OVERLAP
) {
6465 if (build_overlap_sched_groups(sd
, i
))
6468 if (build_sched_groups(sd
, i
))
6474 /* Calculate CPU power for physical packages and nodes */
6475 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6476 if (!cpumask_test_cpu(i
, cpu_map
))
6479 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6480 claim_allocations(i
, sd
);
6481 init_sched_groups_capacity(i
, sd
);
6485 /* Attach the domains */
6487 for_each_cpu(i
, cpu_map
) {
6488 sd
= *per_cpu_ptr(d
.sd
, i
);
6489 cpu_attach_domain(sd
, d
.rd
, i
);
6495 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6499 static cpumask_var_t
*doms_cur
; /* current sched domains */
6500 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6501 static struct sched_domain_attr
*dattr_cur
;
6502 /* attribues of custom domains in 'doms_cur' */
6505 * Special case: If a kmalloc of a doms_cur partition (array of
6506 * cpumask) fails, then fallback to a single sched domain,
6507 * as determined by the single cpumask fallback_doms.
6509 static cpumask_var_t fallback_doms
;
6512 * arch_update_cpu_topology lets virtualized architectures update the
6513 * cpu core maps. It is supposed to return 1 if the topology changed
6514 * or 0 if it stayed the same.
6516 int __weak
arch_update_cpu_topology(void)
6521 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6524 cpumask_var_t
*doms
;
6526 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6529 for (i
= 0; i
< ndoms
; i
++) {
6530 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6531 free_sched_domains(doms
, i
);
6538 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6541 for (i
= 0; i
< ndoms
; i
++)
6542 free_cpumask_var(doms
[i
]);
6547 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6548 * For now this just excludes isolated cpus, but could be used to
6549 * exclude other special cases in the future.
6551 static int init_sched_domains(const struct cpumask
*cpu_map
)
6555 arch_update_cpu_topology();
6557 doms_cur
= alloc_sched_domains(ndoms_cur
);
6559 doms_cur
= &fallback_doms
;
6560 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6561 err
= build_sched_domains(doms_cur
[0], NULL
);
6562 register_sched_domain_sysctl();
6568 * Detach sched domains from a group of cpus specified in cpu_map
6569 * These cpus will now be attached to the NULL domain
6571 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6576 for_each_cpu(i
, cpu_map
)
6577 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6581 /* handle null as "default" */
6582 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6583 struct sched_domain_attr
*new, int idx_new
)
6585 struct sched_domain_attr tmp
;
6592 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6593 new ? (new + idx_new
) : &tmp
,
6594 sizeof(struct sched_domain_attr
));
6598 * Partition sched domains as specified by the 'ndoms_new'
6599 * cpumasks in the array doms_new[] of cpumasks. This compares
6600 * doms_new[] to the current sched domain partitioning, doms_cur[].
6601 * It destroys each deleted domain and builds each new domain.
6603 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6604 * The masks don't intersect (don't overlap.) We should setup one
6605 * sched domain for each mask. CPUs not in any of the cpumasks will
6606 * not be load balanced. If the same cpumask appears both in the
6607 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6610 * The passed in 'doms_new' should be allocated using
6611 * alloc_sched_domains. This routine takes ownership of it and will
6612 * free_sched_domains it when done with it. If the caller failed the
6613 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6614 * and partition_sched_domains() will fallback to the single partition
6615 * 'fallback_doms', it also forces the domains to be rebuilt.
6617 * If doms_new == NULL it will be replaced with cpu_online_mask.
6618 * ndoms_new == 0 is a special case for destroying existing domains,
6619 * and it will not create the default domain.
6621 * Call with hotplug lock held
6623 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6624 struct sched_domain_attr
*dattr_new
)
6629 mutex_lock(&sched_domains_mutex
);
6631 /* always unregister in case we don't destroy any domains */
6632 unregister_sched_domain_sysctl();
6634 /* Let architecture update cpu core mappings. */
6635 new_topology
= arch_update_cpu_topology();
6637 n
= doms_new
? ndoms_new
: 0;
6639 /* Destroy deleted domains */
6640 for (i
= 0; i
< ndoms_cur
; i
++) {
6641 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6642 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6643 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6646 /* no match - a current sched domain not in new doms_new[] */
6647 detach_destroy_domains(doms_cur
[i
]);
6653 if (doms_new
== NULL
) {
6655 doms_new
= &fallback_doms
;
6656 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6657 WARN_ON_ONCE(dattr_new
);
6660 /* Build new domains */
6661 for (i
= 0; i
< ndoms_new
; i
++) {
6662 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6663 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6664 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6667 /* no match - add a new doms_new */
6668 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6673 /* Remember the new sched domains */
6674 if (doms_cur
!= &fallback_doms
)
6675 free_sched_domains(doms_cur
, ndoms_cur
);
6676 kfree(dattr_cur
); /* kfree(NULL) is safe */
6677 doms_cur
= doms_new
;
6678 dattr_cur
= dattr_new
;
6679 ndoms_cur
= ndoms_new
;
6681 register_sched_domain_sysctl();
6683 mutex_unlock(&sched_domains_mutex
);
6686 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6689 * Update cpusets according to cpu_active mask. If cpusets are
6690 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6691 * around partition_sched_domains().
6693 * If we come here as part of a suspend/resume, don't touch cpusets because we
6694 * want to restore it back to its original state upon resume anyway.
6696 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6700 case CPU_ONLINE_FROZEN
:
6701 case CPU_DOWN_FAILED_FROZEN
:
6704 * num_cpus_frozen tracks how many CPUs are involved in suspend
6705 * resume sequence. As long as this is not the last online
6706 * operation in the resume sequence, just build a single sched
6707 * domain, ignoring cpusets.
6710 if (likely(num_cpus_frozen
)) {
6711 partition_sched_domains(1, NULL
, NULL
);
6716 * This is the last CPU online operation. So fall through and
6717 * restore the original sched domains by considering the
6718 * cpuset configurations.
6722 case CPU_DOWN_FAILED
:
6723 cpuset_update_active_cpus(true);
6731 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6735 case CPU_DOWN_PREPARE
:
6736 cpuset_update_active_cpus(false);
6738 case CPU_DOWN_PREPARE_FROZEN
:
6740 partition_sched_domains(1, NULL
, NULL
);
6748 void __init
sched_init_smp(void)
6750 cpumask_var_t non_isolated_cpus
;
6752 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6753 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6758 * There's no userspace yet to cause hotplug operations; hence all the
6759 * cpu masks are stable and all blatant races in the below code cannot
6762 mutex_lock(&sched_domains_mutex
);
6763 init_sched_domains(cpu_active_mask
);
6764 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6765 if (cpumask_empty(non_isolated_cpus
))
6766 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6767 mutex_unlock(&sched_domains_mutex
);
6769 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
6770 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6771 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6775 /* Move init over to a non-isolated CPU */
6776 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6778 sched_init_granularity();
6779 free_cpumask_var(non_isolated_cpus
);
6781 init_sched_rt_class();
6782 init_sched_dl_class();
6785 void __init
sched_init_smp(void)
6787 sched_init_granularity();
6789 #endif /* CONFIG_SMP */
6791 const_debug
unsigned int sysctl_timer_migration
= 1;
6793 int in_sched_functions(unsigned long addr
)
6795 return in_lock_functions(addr
) ||
6796 (addr
>= (unsigned long)__sched_text_start
6797 && addr
< (unsigned long)__sched_text_end
);
6800 #ifdef CONFIG_CGROUP_SCHED
6802 * Default task group.
6803 * Every task in system belongs to this group at bootup.
6805 struct task_group root_task_group
;
6806 LIST_HEAD(task_groups
);
6809 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
6811 void __init
sched_init(void)
6814 unsigned long alloc_size
= 0, ptr
;
6816 #ifdef CONFIG_FAIR_GROUP_SCHED
6817 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6819 #ifdef CONFIG_RT_GROUP_SCHED
6820 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6822 #ifdef CONFIG_CPUMASK_OFFSTACK
6823 alloc_size
+= num_possible_cpus() * cpumask_size();
6826 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6828 #ifdef CONFIG_FAIR_GROUP_SCHED
6829 root_task_group
.se
= (struct sched_entity
**)ptr
;
6830 ptr
+= nr_cpu_ids
* sizeof(void **);
6832 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6833 ptr
+= nr_cpu_ids
* sizeof(void **);
6835 #endif /* CONFIG_FAIR_GROUP_SCHED */
6836 #ifdef CONFIG_RT_GROUP_SCHED
6837 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6838 ptr
+= nr_cpu_ids
* sizeof(void **);
6840 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6841 ptr
+= nr_cpu_ids
* sizeof(void **);
6843 #endif /* CONFIG_RT_GROUP_SCHED */
6844 #ifdef CONFIG_CPUMASK_OFFSTACK
6845 for_each_possible_cpu(i
) {
6846 per_cpu(load_balance_mask
, i
) = (void *)ptr
;
6847 ptr
+= cpumask_size();
6849 #endif /* CONFIG_CPUMASK_OFFSTACK */
6852 init_rt_bandwidth(&def_rt_bandwidth
,
6853 global_rt_period(), global_rt_runtime());
6854 init_dl_bandwidth(&def_dl_bandwidth
,
6855 global_rt_period(), global_rt_runtime());
6858 init_defrootdomain();
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 for_each_possible_cpu(i
) {
6878 raw_spin_lock_init(&rq
->lock
);
6880 rq
->calc_load_active
= 0;
6881 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6882 init_cfs_rq(&rq
->cfs
);
6883 init_rt_rq(&rq
->rt
, rq
);
6884 init_dl_rq(&rq
->dl
, rq
);
6885 #ifdef CONFIG_FAIR_GROUP_SCHED
6886 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6887 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6889 * How much cpu bandwidth does root_task_group get?
6891 * In case of task-groups formed thr' the cgroup filesystem, it
6892 * gets 100% of the cpu resources in the system. This overall
6893 * system cpu resource is divided among the tasks of
6894 * root_task_group and its child task-groups in a fair manner,
6895 * based on each entity's (task or task-group's) weight
6896 * (se->load.weight).
6898 * In other words, if root_task_group has 10 tasks of weight
6899 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6900 * then A0's share of the cpu resource is:
6902 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6904 * We achieve this by letting root_task_group's tasks sit
6905 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6907 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6908 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6909 #endif /* CONFIG_FAIR_GROUP_SCHED */
6911 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6912 #ifdef CONFIG_RT_GROUP_SCHED
6913 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6916 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6917 rq
->cpu_load
[j
] = 0;
6919 rq
->last_load_update_tick
= jiffies
;
6924 rq
->cpu_power
= SCHED_POWER_SCALE
;
6925 rq
->post_schedule
= 0;
6926 rq
->active_balance
= 0;
6927 rq
->next_balance
= jiffies
;
6932 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
6933 rq
->max_idle_balance_cost
= sysctl_sched_migration_cost
;
6935 INIT_LIST_HEAD(&rq
->cfs_tasks
);
6937 rq_attach_root(rq
, &def_root_domain
);
6938 #ifdef CONFIG_NO_HZ_COMMON
6941 #ifdef CONFIG_NO_HZ_FULL
6942 rq
->last_sched_tick
= 0;
6946 atomic_set(&rq
->nr_iowait
, 0);
6949 set_load_weight(&init_task
);
6951 #ifdef CONFIG_PREEMPT_NOTIFIERS
6952 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
6956 * The boot idle thread does lazy MMU switching as well:
6958 atomic_inc(&init_mm
.mm_count
);
6959 enter_lazy_tlb(&init_mm
, current
);
6962 * Make us the idle thread. Technically, schedule() should not be
6963 * called from this thread, however somewhere below it might be,
6964 * but because we are the idle thread, we just pick up running again
6965 * when this runqueue becomes "idle".
6967 init_idle(current
, smp_processor_id());
6969 calc_load_update
= jiffies
+ LOAD_FREQ
;
6972 * During early bootup we pretend to be a normal task:
6974 current
->sched_class
= &fair_sched_class
;
6977 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
6978 /* May be allocated at isolcpus cmdline parse time */
6979 if (cpu_isolated_map
== NULL
)
6980 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
6981 idle_thread_set_boot_cpu();
6982 set_cpu_rq_start_time();
6984 init_sched_fair_class();
6986 scheduler_running
= 1;
6989 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6990 static inline int preempt_count_equals(int preempt_offset
)
6992 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
6994 return (nested
== preempt_offset
);
6997 void __might_sleep(const char *file
, int line
, int preempt_offset
)
6999 static unsigned long prev_jiffy
; /* ratelimiting */
7001 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7002 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled() &&
7003 !is_idle_task(current
)) ||
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
);
7021 #ifdef CONFIG_DEBUG_PREEMPT
7022 if (!preempt_count_equals(preempt_offset
)) {
7023 pr_err("Preemption disabled at:");
7024 print_ip_sym(current
->preempt_disable_ip
);
7030 EXPORT_SYMBOL(__might_sleep
);
7033 #ifdef CONFIG_MAGIC_SYSRQ
7034 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7036 const struct sched_class
*prev_class
= p
->sched_class
;
7037 struct sched_attr attr
= {
7038 .sched_policy
= SCHED_NORMAL
,
7040 int old_prio
= p
->prio
;
7045 dequeue_task(rq
, p
, 0);
7046 __setscheduler(rq
, p
, &attr
);
7048 enqueue_task(rq
, p
, 0);
7049 resched_task(rq
->curr
);
7052 check_class_changed(rq
, p
, prev_class
, old_prio
);
7055 void normalize_rt_tasks(void)
7057 struct task_struct
*g
, *p
;
7058 unsigned long flags
;
7061 read_lock_irqsave(&tasklist_lock
, flags
);
7062 do_each_thread(g
, p
) {
7064 * Only normalize user tasks:
7069 p
->se
.exec_start
= 0;
7070 #ifdef CONFIG_SCHEDSTATS
7071 p
->se
.statistics
.wait_start
= 0;
7072 p
->se
.statistics
.sleep_start
= 0;
7073 p
->se
.statistics
.block_start
= 0;
7076 if (!dl_task(p
) && !rt_task(p
)) {
7078 * Renice negative nice level userspace
7081 if (task_nice(p
) < 0 && p
->mm
)
7082 set_user_nice(p
, 0);
7086 raw_spin_lock(&p
->pi_lock
);
7087 rq
= __task_rq_lock(p
);
7089 normalize_task(rq
, p
);
7091 __task_rq_unlock(rq
);
7092 raw_spin_unlock(&p
->pi_lock
);
7093 } while_each_thread(g
, p
);
7095 read_unlock_irqrestore(&tasklist_lock
, flags
);
7098 #endif /* CONFIG_MAGIC_SYSRQ */
7100 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7102 * These functions are only useful for the IA64 MCA handling, or kdb.
7104 * They can only be called when the whole system has been
7105 * stopped - every CPU needs to be quiescent, and no scheduling
7106 * activity can take place. Using them for anything else would
7107 * be a serious bug, and as a result, they aren't even visible
7108 * under any other configuration.
7112 * curr_task - return the current task for a given cpu.
7113 * @cpu: the processor in question.
7115 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7117 * Return: The current task for @cpu.
7119 struct task_struct
*curr_task(int cpu
)
7121 return cpu_curr(cpu
);
7124 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7128 * set_curr_task - set the current task for a given cpu.
7129 * @cpu: the processor in question.
7130 * @p: the task pointer to set.
7132 * Description: This function must only be used when non-maskable interrupts
7133 * are serviced on a separate stack. It allows the architecture to switch the
7134 * notion of the current task on a cpu in a non-blocking manner. This function
7135 * must be called with all CPU's synchronized, and interrupts disabled, the
7136 * and caller must save the original value of the current task (see
7137 * curr_task() above) and restore that value before reenabling interrupts and
7138 * re-starting the system.
7140 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7142 void set_curr_task(int cpu
, struct task_struct
*p
)
7149 #ifdef CONFIG_CGROUP_SCHED
7150 /* task_group_lock serializes the addition/removal of task groups */
7151 static DEFINE_SPINLOCK(task_group_lock
);
7153 static void free_sched_group(struct task_group
*tg
)
7155 free_fair_sched_group(tg
);
7156 free_rt_sched_group(tg
);
7161 /* allocate runqueue etc for a new task group */
7162 struct task_group
*sched_create_group(struct task_group
*parent
)
7164 struct task_group
*tg
;
7166 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7168 return ERR_PTR(-ENOMEM
);
7170 if (!alloc_fair_sched_group(tg
, parent
))
7173 if (!alloc_rt_sched_group(tg
, parent
))
7179 free_sched_group(tg
);
7180 return ERR_PTR(-ENOMEM
);
7183 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
7185 unsigned long flags
;
7187 spin_lock_irqsave(&task_group_lock
, flags
);
7188 list_add_rcu(&tg
->list
, &task_groups
);
7190 WARN_ON(!parent
); /* root should already exist */
7192 tg
->parent
= parent
;
7193 INIT_LIST_HEAD(&tg
->children
);
7194 list_add_rcu(&tg
->siblings
, &parent
->children
);
7195 spin_unlock_irqrestore(&task_group_lock
, flags
);
7198 /* rcu callback to free various structures associated with a task group */
7199 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7201 /* now it should be safe to free those cfs_rqs */
7202 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7205 /* Destroy runqueue etc associated with a task group */
7206 void sched_destroy_group(struct task_group
*tg
)
7208 /* wait for possible concurrent references to cfs_rqs complete */
7209 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7212 void sched_offline_group(struct task_group
*tg
)
7214 unsigned long flags
;
7217 /* end participation in shares distribution */
7218 for_each_possible_cpu(i
)
7219 unregister_fair_sched_group(tg
, i
);
7221 spin_lock_irqsave(&task_group_lock
, flags
);
7222 list_del_rcu(&tg
->list
);
7223 list_del_rcu(&tg
->siblings
);
7224 spin_unlock_irqrestore(&task_group_lock
, flags
);
7227 /* change task's runqueue when it moves between groups.
7228 * The caller of this function should have put the task in its new group
7229 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7230 * reflect its new group.
7232 void sched_move_task(struct task_struct
*tsk
)
7234 struct task_group
*tg
;
7236 unsigned long flags
;
7239 rq
= task_rq_lock(tsk
, &flags
);
7241 running
= task_current(rq
, tsk
);
7245 dequeue_task(rq
, tsk
, 0);
7246 if (unlikely(running
))
7247 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7249 tg
= container_of(task_css_check(tsk
, cpu_cgrp_id
,
7250 lockdep_is_held(&tsk
->sighand
->siglock
)),
7251 struct task_group
, css
);
7252 tg
= autogroup_task_group(tsk
, tg
);
7253 tsk
->sched_task_group
= tg
;
7255 #ifdef CONFIG_FAIR_GROUP_SCHED
7256 if (tsk
->sched_class
->task_move_group
)
7257 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
7260 set_task_rq(tsk
, task_cpu(tsk
));
7262 if (unlikely(running
))
7263 tsk
->sched_class
->set_curr_task(rq
);
7265 enqueue_task(rq
, tsk
, 0);
7267 task_rq_unlock(rq
, tsk
, &flags
);
7269 #endif /* CONFIG_CGROUP_SCHED */
7271 #ifdef CONFIG_RT_GROUP_SCHED
7273 * Ensure that the real time constraints are schedulable.
7275 static DEFINE_MUTEX(rt_constraints_mutex
);
7277 /* Must be called with tasklist_lock held */
7278 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7280 struct task_struct
*g
, *p
;
7282 do_each_thread(g
, p
) {
7283 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
7285 } while_each_thread(g
, p
);
7290 struct rt_schedulable_data
{
7291 struct task_group
*tg
;
7296 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7298 struct rt_schedulable_data
*d
= data
;
7299 struct task_group
*child
;
7300 unsigned long total
, sum
= 0;
7301 u64 period
, runtime
;
7303 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7304 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7307 period
= d
->rt_period
;
7308 runtime
= d
->rt_runtime
;
7312 * Cannot have more runtime than the period.
7314 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7318 * Ensure we don't starve existing RT tasks.
7320 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7323 total
= to_ratio(period
, runtime
);
7326 * Nobody can have more than the global setting allows.
7328 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7332 * The sum of our children's runtime should not exceed our own.
7334 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7335 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7336 runtime
= child
->rt_bandwidth
.rt_runtime
;
7338 if (child
== d
->tg
) {
7339 period
= d
->rt_period
;
7340 runtime
= d
->rt_runtime
;
7343 sum
+= to_ratio(period
, runtime
);
7352 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7356 struct rt_schedulable_data data
= {
7358 .rt_period
= period
,
7359 .rt_runtime
= runtime
,
7363 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7369 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7370 u64 rt_period
, u64 rt_runtime
)
7374 mutex_lock(&rt_constraints_mutex
);
7375 read_lock(&tasklist_lock
);
7376 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7380 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7381 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7382 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7384 for_each_possible_cpu(i
) {
7385 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7387 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7388 rt_rq
->rt_runtime
= rt_runtime
;
7389 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7391 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7393 read_unlock(&tasklist_lock
);
7394 mutex_unlock(&rt_constraints_mutex
);
7399 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7401 u64 rt_runtime
, rt_period
;
7403 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7404 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7405 if (rt_runtime_us
< 0)
7406 rt_runtime
= RUNTIME_INF
;
7408 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7411 static long sched_group_rt_runtime(struct task_group
*tg
)
7415 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7418 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7419 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7420 return rt_runtime_us
;
7423 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7425 u64 rt_runtime
, rt_period
;
7427 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7428 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7433 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7436 static long sched_group_rt_period(struct task_group
*tg
)
7440 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7441 do_div(rt_period_us
, NSEC_PER_USEC
);
7442 return rt_period_us
;
7444 #endif /* CONFIG_RT_GROUP_SCHED */
7446 #ifdef CONFIG_RT_GROUP_SCHED
7447 static int sched_rt_global_constraints(void)
7451 mutex_lock(&rt_constraints_mutex
);
7452 read_lock(&tasklist_lock
);
7453 ret
= __rt_schedulable(NULL
, 0, 0);
7454 read_unlock(&tasklist_lock
);
7455 mutex_unlock(&rt_constraints_mutex
);
7460 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7462 /* Don't accept realtime tasks when there is no way for them to run */
7463 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7469 #else /* !CONFIG_RT_GROUP_SCHED */
7470 static int sched_rt_global_constraints(void)
7472 unsigned long flags
;
7475 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7476 for_each_possible_cpu(i
) {
7477 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7479 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7480 rt_rq
->rt_runtime
= global_rt_runtime();
7481 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7483 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7487 #endif /* CONFIG_RT_GROUP_SCHED */
7489 static int sched_dl_global_constraints(void)
7491 u64 runtime
= global_rt_runtime();
7492 u64 period
= global_rt_period();
7493 u64 new_bw
= to_ratio(period
, runtime
);
7495 unsigned long flags
;
7498 * Here we want to check the bandwidth not being set to some
7499 * value smaller than the currently allocated bandwidth in
7500 * any of the root_domains.
7502 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7503 * cycling on root_domains... Discussion on different/better
7504 * solutions is welcome!
7506 for_each_possible_cpu(cpu
) {
7507 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
7509 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7510 if (new_bw
< dl_b
->total_bw
)
7512 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7521 static void sched_dl_do_global(void)
7525 unsigned long flags
;
7527 def_dl_bandwidth
.dl_period
= global_rt_period();
7528 def_dl_bandwidth
.dl_runtime
= global_rt_runtime();
7530 if (global_rt_runtime() != RUNTIME_INF
)
7531 new_bw
= to_ratio(global_rt_period(), global_rt_runtime());
7534 * FIXME: As above...
7536 for_each_possible_cpu(cpu
) {
7537 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
7539 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7541 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7545 static int sched_rt_global_validate(void)
7547 if (sysctl_sched_rt_period
<= 0)
7550 if ((sysctl_sched_rt_runtime
!= RUNTIME_INF
) &&
7551 (sysctl_sched_rt_runtime
> sysctl_sched_rt_period
))
7557 static void sched_rt_do_global(void)
7559 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7560 def_rt_bandwidth
.rt_period
= ns_to_ktime(global_rt_period());
7563 int sched_rt_handler(struct ctl_table
*table
, int write
,
7564 void __user
*buffer
, size_t *lenp
,
7567 int old_period
, old_runtime
;
7568 static DEFINE_MUTEX(mutex
);
7572 old_period
= sysctl_sched_rt_period
;
7573 old_runtime
= sysctl_sched_rt_runtime
;
7575 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7577 if (!ret
&& write
) {
7578 ret
= sched_rt_global_validate();
7582 ret
= sched_rt_global_constraints();
7586 ret
= sched_dl_global_constraints();
7590 sched_rt_do_global();
7591 sched_dl_do_global();
7595 sysctl_sched_rt_period
= old_period
;
7596 sysctl_sched_rt_runtime
= old_runtime
;
7598 mutex_unlock(&mutex
);
7603 int sched_rr_handler(struct ctl_table
*table
, int write
,
7604 void __user
*buffer
, size_t *lenp
,
7608 static DEFINE_MUTEX(mutex
);
7611 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7612 /* make sure that internally we keep jiffies */
7613 /* also, writing zero resets timeslice to default */
7614 if (!ret
&& write
) {
7615 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7616 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7618 mutex_unlock(&mutex
);
7622 #ifdef CONFIG_CGROUP_SCHED
7624 static inline struct task_group
*css_tg(struct cgroup_subsys_state
*css
)
7626 return css
? container_of(css
, struct task_group
, css
) : NULL
;
7629 static struct cgroup_subsys_state
*
7630 cpu_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
7632 struct task_group
*parent
= css_tg(parent_css
);
7633 struct task_group
*tg
;
7636 /* This is early initialization for the top cgroup */
7637 return &root_task_group
.css
;
7640 tg
= sched_create_group(parent
);
7642 return ERR_PTR(-ENOMEM
);
7647 static int cpu_cgroup_css_online(struct cgroup_subsys_state
*css
)
7649 struct task_group
*tg
= css_tg(css
);
7650 struct task_group
*parent
= css_tg(css_parent(css
));
7653 sched_online_group(tg
, parent
);
7657 static void cpu_cgroup_css_free(struct cgroup_subsys_state
*css
)
7659 struct task_group
*tg
= css_tg(css
);
7661 sched_destroy_group(tg
);
7664 static void cpu_cgroup_css_offline(struct cgroup_subsys_state
*css
)
7666 struct task_group
*tg
= css_tg(css
);
7668 sched_offline_group(tg
);
7671 static int cpu_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7672 struct cgroup_taskset
*tset
)
7674 struct task_struct
*task
;
7676 cgroup_taskset_for_each(task
, tset
) {
7677 #ifdef CONFIG_RT_GROUP_SCHED
7678 if (!sched_rt_can_attach(css_tg(css
), task
))
7681 /* We don't support RT-tasks being in separate groups */
7682 if (task
->sched_class
!= &fair_sched_class
)
7689 static void cpu_cgroup_attach(struct cgroup_subsys_state
*css
,
7690 struct cgroup_taskset
*tset
)
7692 struct task_struct
*task
;
7694 cgroup_taskset_for_each(task
, tset
)
7695 sched_move_task(task
);
7698 static void cpu_cgroup_exit(struct cgroup_subsys_state
*css
,
7699 struct cgroup_subsys_state
*old_css
,
7700 struct task_struct
*task
)
7703 * cgroup_exit() is called in the copy_process() failure path.
7704 * Ignore this case since the task hasn't ran yet, this avoids
7705 * trying to poke a half freed task state from generic code.
7707 if (!(task
->flags
& PF_EXITING
))
7710 sched_move_task(task
);
7713 #ifdef CONFIG_FAIR_GROUP_SCHED
7714 static int cpu_shares_write_u64(struct cgroup_subsys_state
*css
,
7715 struct cftype
*cftype
, u64 shareval
)
7717 return sched_group_set_shares(css_tg(css
), scale_load(shareval
));
7720 static u64
cpu_shares_read_u64(struct cgroup_subsys_state
*css
,
7723 struct task_group
*tg
= css_tg(css
);
7725 return (u64
) scale_load_down(tg
->shares
);
7728 #ifdef CONFIG_CFS_BANDWIDTH
7729 static DEFINE_MUTEX(cfs_constraints_mutex
);
7731 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7732 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7734 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7736 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7738 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7739 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7741 if (tg
== &root_task_group
)
7745 * Ensure we have at some amount of bandwidth every period. This is
7746 * to prevent reaching a state of large arrears when throttled via
7747 * entity_tick() resulting in prolonged exit starvation.
7749 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7753 * Likewise, bound things on the otherside by preventing insane quota
7754 * periods. This also allows us to normalize in computing quota
7757 if (period
> max_cfs_quota_period
)
7760 mutex_lock(&cfs_constraints_mutex
);
7761 ret
= __cfs_schedulable(tg
, period
, quota
);
7765 runtime_enabled
= quota
!= RUNTIME_INF
;
7766 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7768 * If we need to toggle cfs_bandwidth_used, off->on must occur
7769 * before making related changes, and on->off must occur afterwards
7771 if (runtime_enabled
&& !runtime_was_enabled
)
7772 cfs_bandwidth_usage_inc();
7773 raw_spin_lock_irq(&cfs_b
->lock
);
7774 cfs_b
->period
= ns_to_ktime(period
);
7775 cfs_b
->quota
= quota
;
7777 __refill_cfs_bandwidth_runtime(cfs_b
);
7778 /* restart the period timer (if active) to handle new period expiry */
7779 if (runtime_enabled
&& cfs_b
->timer_active
) {
7780 /* force a reprogram */
7781 cfs_b
->timer_active
= 0;
7782 __start_cfs_bandwidth(cfs_b
);
7784 raw_spin_unlock_irq(&cfs_b
->lock
);
7786 for_each_possible_cpu(i
) {
7787 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7788 struct rq
*rq
= cfs_rq
->rq
;
7790 raw_spin_lock_irq(&rq
->lock
);
7791 cfs_rq
->runtime_enabled
= runtime_enabled
;
7792 cfs_rq
->runtime_remaining
= 0;
7794 if (cfs_rq
->throttled
)
7795 unthrottle_cfs_rq(cfs_rq
);
7796 raw_spin_unlock_irq(&rq
->lock
);
7798 if (runtime_was_enabled
&& !runtime_enabled
)
7799 cfs_bandwidth_usage_dec();
7801 mutex_unlock(&cfs_constraints_mutex
);
7806 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7810 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7811 if (cfs_quota_us
< 0)
7812 quota
= RUNTIME_INF
;
7814 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7816 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7819 long tg_get_cfs_quota(struct task_group
*tg
)
7823 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7826 quota_us
= tg
->cfs_bandwidth
.quota
;
7827 do_div(quota_us
, NSEC_PER_USEC
);
7832 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7836 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7837 quota
= tg
->cfs_bandwidth
.quota
;
7839 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7842 long tg_get_cfs_period(struct task_group
*tg
)
7846 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7847 do_div(cfs_period_us
, NSEC_PER_USEC
);
7849 return cfs_period_us
;
7852 static s64
cpu_cfs_quota_read_s64(struct cgroup_subsys_state
*css
,
7855 return tg_get_cfs_quota(css_tg(css
));
7858 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state
*css
,
7859 struct cftype
*cftype
, s64 cfs_quota_us
)
7861 return tg_set_cfs_quota(css_tg(css
), cfs_quota_us
);
7864 static u64
cpu_cfs_period_read_u64(struct cgroup_subsys_state
*css
,
7867 return tg_get_cfs_period(css_tg(css
));
7870 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state
*css
,
7871 struct cftype
*cftype
, u64 cfs_period_us
)
7873 return tg_set_cfs_period(css_tg(css
), cfs_period_us
);
7876 struct cfs_schedulable_data
{
7877 struct task_group
*tg
;
7882 * normalize group quota/period to be quota/max_period
7883 * note: units are usecs
7885 static u64
normalize_cfs_quota(struct task_group
*tg
,
7886 struct cfs_schedulable_data
*d
)
7894 period
= tg_get_cfs_period(tg
);
7895 quota
= tg_get_cfs_quota(tg
);
7898 /* note: these should typically be equivalent */
7899 if (quota
== RUNTIME_INF
|| quota
== -1)
7902 return to_ratio(period
, quota
);
7905 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7907 struct cfs_schedulable_data
*d
= data
;
7908 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7909 s64 quota
= 0, parent_quota
= -1;
7912 quota
= RUNTIME_INF
;
7914 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
7916 quota
= normalize_cfs_quota(tg
, d
);
7917 parent_quota
= parent_b
->hierarchal_quota
;
7920 * ensure max(child_quota) <= parent_quota, inherit when no
7923 if (quota
== RUNTIME_INF
)
7924 quota
= parent_quota
;
7925 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
7928 cfs_b
->hierarchal_quota
= quota
;
7933 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
7936 struct cfs_schedulable_data data
= {
7942 if (quota
!= RUNTIME_INF
) {
7943 do_div(data
.period
, NSEC_PER_USEC
);
7944 do_div(data
.quota
, NSEC_PER_USEC
);
7948 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
7954 static int cpu_stats_show(struct seq_file
*sf
, void *v
)
7956 struct task_group
*tg
= css_tg(seq_css(sf
));
7957 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7959 seq_printf(sf
, "nr_periods %d\n", cfs_b
->nr_periods
);
7960 seq_printf(sf
, "nr_throttled %d\n", cfs_b
->nr_throttled
);
7961 seq_printf(sf
, "throttled_time %llu\n", cfs_b
->throttled_time
);
7965 #endif /* CONFIG_CFS_BANDWIDTH */
7966 #endif /* CONFIG_FAIR_GROUP_SCHED */
7968 #ifdef CONFIG_RT_GROUP_SCHED
7969 static int cpu_rt_runtime_write(struct cgroup_subsys_state
*css
,
7970 struct cftype
*cft
, s64 val
)
7972 return sched_group_set_rt_runtime(css_tg(css
), val
);
7975 static s64
cpu_rt_runtime_read(struct cgroup_subsys_state
*css
,
7978 return sched_group_rt_runtime(css_tg(css
));
7981 static int cpu_rt_period_write_uint(struct cgroup_subsys_state
*css
,
7982 struct cftype
*cftype
, u64 rt_period_us
)
7984 return sched_group_set_rt_period(css_tg(css
), rt_period_us
);
7987 static u64
cpu_rt_period_read_uint(struct cgroup_subsys_state
*css
,
7990 return sched_group_rt_period(css_tg(css
));
7992 #endif /* CONFIG_RT_GROUP_SCHED */
7994 static struct cftype cpu_files
[] = {
7995 #ifdef CONFIG_FAIR_GROUP_SCHED
7998 .read_u64
= cpu_shares_read_u64
,
7999 .write_u64
= cpu_shares_write_u64
,
8002 #ifdef CONFIG_CFS_BANDWIDTH
8004 .name
= "cfs_quota_us",
8005 .read_s64
= cpu_cfs_quota_read_s64
,
8006 .write_s64
= cpu_cfs_quota_write_s64
,
8009 .name
= "cfs_period_us",
8010 .read_u64
= cpu_cfs_period_read_u64
,
8011 .write_u64
= cpu_cfs_period_write_u64
,
8015 .seq_show
= cpu_stats_show
,
8018 #ifdef CONFIG_RT_GROUP_SCHED
8020 .name
= "rt_runtime_us",
8021 .read_s64
= cpu_rt_runtime_read
,
8022 .write_s64
= cpu_rt_runtime_write
,
8025 .name
= "rt_period_us",
8026 .read_u64
= cpu_rt_period_read_uint
,
8027 .write_u64
= cpu_rt_period_write_uint
,
8033 struct cgroup_subsys cpu_cgrp_subsys
= {
8034 .css_alloc
= cpu_cgroup_css_alloc
,
8035 .css_free
= cpu_cgroup_css_free
,
8036 .css_online
= cpu_cgroup_css_online
,
8037 .css_offline
= cpu_cgroup_css_offline
,
8038 .can_attach
= cpu_cgroup_can_attach
,
8039 .attach
= cpu_cgroup_attach
,
8040 .exit
= cpu_cgroup_exit
,
8041 .base_cftypes
= cpu_files
,
8045 #endif /* CONFIG_CGROUP_SCHED */
8047 void dump_cpu_task(int cpu
)
8049 pr_info("Task dump for CPU %d:\n", cpu
);
8050 sched_show_task(cpu_curr(cpu
));