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 * resched_task - mark a task 'to be rescheduled now'.
511 * On UP this means the setting of the need_resched flag, on SMP it
512 * might also involve a cross-CPU call to trigger the scheduler on
515 void resched_task(struct task_struct
*p
)
519 lockdep_assert_held(&task_rq(p
)->lock
);
521 if (test_tsk_need_resched(p
))
524 set_tsk_need_resched(p
);
527 if (cpu
== smp_processor_id()) {
528 set_preempt_need_resched();
532 /* NEED_RESCHED must be visible before we test polling */
534 if (!tsk_is_polling(p
))
535 smp_send_reschedule(cpu
);
538 void resched_cpu(int cpu
)
540 struct rq
*rq
= cpu_rq(cpu
);
543 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
545 resched_task(cpu_curr(cpu
));
546 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
550 #ifdef CONFIG_NO_HZ_COMMON
552 * In the semi idle case, use the nearest busy cpu for migrating timers
553 * from an idle cpu. This is good for power-savings.
555 * We don't do similar optimization for completely idle system, as
556 * selecting an idle cpu will add more delays to the timers than intended
557 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
559 int get_nohz_timer_target(int pinned
)
561 int cpu
= smp_processor_id();
563 struct sched_domain
*sd
;
565 if (pinned
|| !get_sysctl_timer_migration() || !idle_cpu(cpu
))
569 for_each_domain(cpu
, sd
) {
570 for_each_cpu(i
, sched_domain_span(sd
)) {
582 * When add_timer_on() enqueues a timer into the timer wheel of an
583 * idle CPU then this timer might expire before the next timer event
584 * which is scheduled to wake up that CPU. In case of a completely
585 * idle system the next event might even be infinite time into the
586 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
587 * leaves the inner idle loop so the newly added timer is taken into
588 * account when the CPU goes back to idle and evaluates the timer
589 * wheel for the next timer event.
591 static void wake_up_idle_cpu(int cpu
)
593 struct rq
*rq
= cpu_rq(cpu
);
595 if (cpu
== smp_processor_id())
599 * This is safe, as this function is called with the timer
600 * wheel base lock of (cpu) held. When the CPU is on the way
601 * to idle and has not yet set rq->curr to idle then it will
602 * be serialized on the timer wheel base lock and take the new
603 * timer into account automatically.
605 if (rq
->curr
!= rq
->idle
)
609 * We can set TIF_RESCHED on the idle task of the other CPU
610 * lockless. The worst case is that the other CPU runs the
611 * idle task through an additional NOOP schedule()
613 set_tsk_need_resched(rq
->idle
);
615 /* NEED_RESCHED must be visible before we test polling */
617 if (!tsk_is_polling(rq
->idle
))
618 smp_send_reschedule(cpu
);
621 static bool wake_up_full_nohz_cpu(int cpu
)
623 if (tick_nohz_full_cpu(cpu
)) {
624 if (cpu
!= smp_processor_id() ||
625 tick_nohz_tick_stopped())
626 smp_send_reschedule(cpu
);
633 void wake_up_nohz_cpu(int cpu
)
635 if (!wake_up_full_nohz_cpu(cpu
))
636 wake_up_idle_cpu(cpu
);
639 static inline bool got_nohz_idle_kick(void)
641 int cpu
= smp_processor_id();
643 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
646 if (idle_cpu(cpu
) && !need_resched())
650 * We can't run Idle Load Balance on this CPU for this time so we
651 * cancel it and clear NOHZ_BALANCE_KICK
653 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
657 #else /* CONFIG_NO_HZ_COMMON */
659 static inline bool got_nohz_idle_kick(void)
664 #endif /* CONFIG_NO_HZ_COMMON */
666 #ifdef CONFIG_NO_HZ_FULL
667 bool sched_can_stop_tick(void)
673 /* Make sure rq->nr_running update is visible after the IPI */
676 /* More than one running task need preemption */
677 if (rq
->nr_running
> 1)
682 #endif /* CONFIG_NO_HZ_FULL */
684 void sched_avg_update(struct rq
*rq
)
686 s64 period
= sched_avg_period();
688 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
690 * Inline assembly required to prevent the compiler
691 * optimising this loop into a divmod call.
692 * See __iter_div_u64_rem() for another example of this.
694 asm("" : "+rm" (rq
->age_stamp
));
695 rq
->age_stamp
+= period
;
700 #endif /* CONFIG_SMP */
702 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
703 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
705 * Iterate task_group tree rooted at *from, calling @down when first entering a
706 * node and @up when leaving it for the final time.
708 * Caller must hold rcu_lock or sufficient equivalent.
710 int walk_tg_tree_from(struct task_group
*from
,
711 tg_visitor down
, tg_visitor up
, void *data
)
713 struct task_group
*parent
, *child
;
719 ret
= (*down
)(parent
, data
);
722 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
729 ret
= (*up
)(parent
, data
);
730 if (ret
|| parent
== from
)
734 parent
= parent
->parent
;
741 int tg_nop(struct task_group
*tg
, void *data
)
747 static void set_load_weight(struct task_struct
*p
)
749 int prio
= p
->static_prio
- MAX_RT_PRIO
;
750 struct load_weight
*load
= &p
->se
.load
;
753 * SCHED_IDLE tasks get minimal weight:
755 if (p
->policy
== SCHED_IDLE
) {
756 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
757 load
->inv_weight
= WMULT_IDLEPRIO
;
761 load
->weight
= scale_load(prio_to_weight
[prio
]);
762 load
->inv_weight
= prio_to_wmult
[prio
];
765 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
768 sched_info_queued(rq
, p
);
769 p
->sched_class
->enqueue_task(rq
, p
, flags
);
772 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
775 sched_info_dequeued(rq
, p
);
776 p
->sched_class
->dequeue_task(rq
, p
, flags
);
779 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
781 if (task_contributes_to_load(p
))
782 rq
->nr_uninterruptible
--;
784 enqueue_task(rq
, p
, flags
);
787 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
789 if (task_contributes_to_load(p
))
790 rq
->nr_uninterruptible
++;
792 dequeue_task(rq
, p
, flags
);
795 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
798 * In theory, the compile should just see 0 here, and optimize out the call
799 * to sched_rt_avg_update. But I don't trust it...
801 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
802 s64 steal
= 0, irq_delta
= 0;
804 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
805 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
808 * Since irq_time is only updated on {soft,}irq_exit, we might run into
809 * this case when a previous update_rq_clock() happened inside a
812 * When this happens, we stop ->clock_task and only update the
813 * prev_irq_time stamp to account for the part that fit, so that a next
814 * update will consume the rest. This ensures ->clock_task is
817 * It does however cause some slight miss-attribution of {soft,}irq
818 * time, a more accurate solution would be to update the irq_time using
819 * the current rq->clock timestamp, except that would require using
822 if (irq_delta
> delta
)
825 rq
->prev_irq_time
+= irq_delta
;
828 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
829 if (static_key_false((¶virt_steal_rq_enabled
))) {
830 steal
= paravirt_steal_clock(cpu_of(rq
));
831 steal
-= rq
->prev_steal_time_rq
;
833 if (unlikely(steal
> delta
))
836 rq
->prev_steal_time_rq
+= steal
;
841 rq
->clock_task
+= delta
;
843 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
844 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
845 sched_rt_avg_update(rq
, irq_delta
+ steal
);
849 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
851 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
852 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
856 * Make it appear like a SCHED_FIFO task, its something
857 * userspace knows about and won't get confused about.
859 * Also, it will make PI more or less work without too
860 * much confusion -- but then, stop work should not
861 * rely on PI working anyway.
863 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
865 stop
->sched_class
= &stop_sched_class
;
868 cpu_rq(cpu
)->stop
= stop
;
872 * Reset it back to a normal scheduling class so that
873 * it can die in pieces.
875 old_stop
->sched_class
= &rt_sched_class
;
880 * __normal_prio - return the priority that is based on the static prio
882 static inline int __normal_prio(struct task_struct
*p
)
884 return p
->static_prio
;
888 * Calculate the expected normal priority: i.e. priority
889 * without taking RT-inheritance into account. Might be
890 * boosted by interactivity modifiers. Changes upon fork,
891 * setprio syscalls, and whenever the interactivity
892 * estimator recalculates.
894 static inline int normal_prio(struct task_struct
*p
)
898 if (task_has_dl_policy(p
))
899 prio
= MAX_DL_PRIO
-1;
900 else if (task_has_rt_policy(p
))
901 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
903 prio
= __normal_prio(p
);
908 * Calculate the current priority, i.e. the priority
909 * taken into account by the scheduler. This value might
910 * be boosted by RT tasks, or might be boosted by
911 * interactivity modifiers. Will be RT if the task got
912 * RT-boosted. If not then it returns p->normal_prio.
914 static int effective_prio(struct task_struct
*p
)
916 p
->normal_prio
= normal_prio(p
);
918 * If we are RT tasks or we were boosted to RT priority,
919 * keep the priority unchanged. Otherwise, update priority
920 * to the normal priority:
922 if (!rt_prio(p
->prio
))
923 return p
->normal_prio
;
928 * task_curr - is this task currently executing on a CPU?
929 * @p: the task in question.
931 * Return: 1 if the task is currently executing. 0 otherwise.
933 inline int task_curr(const struct task_struct
*p
)
935 return cpu_curr(task_cpu(p
)) == p
;
938 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
939 const struct sched_class
*prev_class
,
942 if (prev_class
!= p
->sched_class
) {
943 if (prev_class
->switched_from
)
944 prev_class
->switched_from(rq
, p
);
945 p
->sched_class
->switched_to(rq
, p
);
946 } else if (oldprio
!= p
->prio
|| dl_task(p
))
947 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
950 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
952 const struct sched_class
*class;
954 if (p
->sched_class
== rq
->curr
->sched_class
) {
955 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
957 for_each_class(class) {
958 if (class == rq
->curr
->sched_class
)
960 if (class == p
->sched_class
) {
961 resched_task(rq
->curr
);
968 * A queue event has occurred, and we're going to schedule. In
969 * this case, we can save a useless back to back clock update.
971 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
972 rq
->skip_clock_update
= 1;
976 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
978 #ifdef CONFIG_SCHED_DEBUG
980 * We should never call set_task_cpu() on a blocked task,
981 * ttwu() will sort out the placement.
983 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
984 !(task_preempt_count(p
) & PREEMPT_ACTIVE
));
986 #ifdef CONFIG_LOCKDEP
988 * The caller should hold either p->pi_lock or rq->lock, when changing
989 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
991 * sched_move_task() holds both and thus holding either pins the cgroup,
994 * Furthermore, all task_rq users should acquire both locks, see
997 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
998 lockdep_is_held(&task_rq(p
)->lock
)));
1002 trace_sched_migrate_task(p
, new_cpu
);
1004 if (task_cpu(p
) != new_cpu
) {
1005 if (p
->sched_class
->migrate_task_rq
)
1006 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1007 p
->se
.nr_migrations
++;
1008 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1011 __set_task_cpu(p
, new_cpu
);
1014 static void __migrate_swap_task(struct task_struct
*p
, int cpu
)
1017 struct rq
*src_rq
, *dst_rq
;
1019 src_rq
= task_rq(p
);
1020 dst_rq
= cpu_rq(cpu
);
1022 deactivate_task(src_rq
, p
, 0);
1023 set_task_cpu(p
, cpu
);
1024 activate_task(dst_rq
, p
, 0);
1025 check_preempt_curr(dst_rq
, p
, 0);
1028 * Task isn't running anymore; make it appear like we migrated
1029 * it before it went to sleep. This means on wakeup we make the
1030 * previous cpu our targer instead of where it really is.
1036 struct migration_swap_arg
{
1037 struct task_struct
*src_task
, *dst_task
;
1038 int src_cpu
, dst_cpu
;
1041 static int migrate_swap_stop(void *data
)
1043 struct migration_swap_arg
*arg
= data
;
1044 struct rq
*src_rq
, *dst_rq
;
1047 src_rq
= cpu_rq(arg
->src_cpu
);
1048 dst_rq
= cpu_rq(arg
->dst_cpu
);
1050 double_raw_lock(&arg
->src_task
->pi_lock
,
1051 &arg
->dst_task
->pi_lock
);
1052 double_rq_lock(src_rq
, dst_rq
);
1053 if (task_cpu(arg
->dst_task
) != arg
->dst_cpu
)
1056 if (task_cpu(arg
->src_task
) != arg
->src_cpu
)
1059 if (!cpumask_test_cpu(arg
->dst_cpu
, tsk_cpus_allowed(arg
->src_task
)))
1062 if (!cpumask_test_cpu(arg
->src_cpu
, tsk_cpus_allowed(arg
->dst_task
)))
1065 __migrate_swap_task(arg
->src_task
, arg
->dst_cpu
);
1066 __migrate_swap_task(arg
->dst_task
, arg
->src_cpu
);
1071 double_rq_unlock(src_rq
, dst_rq
);
1072 raw_spin_unlock(&arg
->dst_task
->pi_lock
);
1073 raw_spin_unlock(&arg
->src_task
->pi_lock
);
1079 * Cross migrate two tasks
1081 int migrate_swap(struct task_struct
*cur
, struct task_struct
*p
)
1083 struct migration_swap_arg arg
;
1086 arg
= (struct migration_swap_arg
){
1088 .src_cpu
= task_cpu(cur
),
1090 .dst_cpu
= task_cpu(p
),
1093 if (arg
.src_cpu
== arg
.dst_cpu
)
1097 * These three tests are all lockless; this is OK since all of them
1098 * will be re-checked with proper locks held further down the line.
1100 if (!cpu_active(arg
.src_cpu
) || !cpu_active(arg
.dst_cpu
))
1103 if (!cpumask_test_cpu(arg
.dst_cpu
, tsk_cpus_allowed(arg
.src_task
)))
1106 if (!cpumask_test_cpu(arg
.src_cpu
, tsk_cpus_allowed(arg
.dst_task
)))
1109 trace_sched_swap_numa(cur
, arg
.src_cpu
, p
, arg
.dst_cpu
);
1110 ret
= stop_two_cpus(arg
.dst_cpu
, arg
.src_cpu
, migrate_swap_stop
, &arg
);
1116 struct migration_arg
{
1117 struct task_struct
*task
;
1121 static int migration_cpu_stop(void *data
);
1124 * wait_task_inactive - wait for a thread to unschedule.
1126 * If @match_state is nonzero, it's the @p->state value just checked and
1127 * not expected to change. If it changes, i.e. @p might have woken up,
1128 * then return zero. When we succeed in waiting for @p to be off its CPU,
1129 * we return a positive number (its total switch count). If a second call
1130 * a short while later returns the same number, the caller can be sure that
1131 * @p has remained unscheduled the whole time.
1133 * The caller must ensure that the task *will* unschedule sometime soon,
1134 * else this function might spin for a *long* time. This function can't
1135 * be called with interrupts off, or it may introduce deadlock with
1136 * smp_call_function() if an IPI is sent by the same process we are
1137 * waiting to become inactive.
1139 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1141 unsigned long flags
;
1148 * We do the initial early heuristics without holding
1149 * any task-queue locks at all. We'll only try to get
1150 * the runqueue lock when things look like they will
1156 * If the task is actively running on another CPU
1157 * still, just relax and busy-wait without holding
1160 * NOTE! Since we don't hold any locks, it's not
1161 * even sure that "rq" stays as the right runqueue!
1162 * But we don't care, since "task_running()" will
1163 * return false if the runqueue has changed and p
1164 * is actually now running somewhere else!
1166 while (task_running(rq
, p
)) {
1167 if (match_state
&& unlikely(p
->state
!= match_state
))
1173 * Ok, time to look more closely! We need the rq
1174 * lock now, to be *sure*. If we're wrong, we'll
1175 * just go back and repeat.
1177 rq
= task_rq_lock(p
, &flags
);
1178 trace_sched_wait_task(p
);
1179 running
= task_running(rq
, p
);
1182 if (!match_state
|| p
->state
== match_state
)
1183 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1184 task_rq_unlock(rq
, p
, &flags
);
1187 * If it changed from the expected state, bail out now.
1189 if (unlikely(!ncsw
))
1193 * Was it really running after all now that we
1194 * checked with the proper locks actually held?
1196 * Oops. Go back and try again..
1198 if (unlikely(running
)) {
1204 * It's not enough that it's not actively running,
1205 * it must be off the runqueue _entirely_, and not
1208 * So if it was still runnable (but just not actively
1209 * running right now), it's preempted, and we should
1210 * yield - it could be a while.
1212 if (unlikely(on_rq
)) {
1213 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1215 set_current_state(TASK_UNINTERRUPTIBLE
);
1216 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1221 * Ahh, all good. It wasn't running, and it wasn't
1222 * runnable, which means that it will never become
1223 * running in the future either. We're all done!
1232 * kick_process - kick a running thread to enter/exit the kernel
1233 * @p: the to-be-kicked thread
1235 * Cause a process which is running on another CPU to enter
1236 * kernel-mode, without any delay. (to get signals handled.)
1238 * NOTE: this function doesn't have to take the runqueue lock,
1239 * because all it wants to ensure is that the remote task enters
1240 * the kernel. If the IPI races and the task has been migrated
1241 * to another CPU then no harm is done and the purpose has been
1244 void kick_process(struct task_struct
*p
)
1250 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1251 smp_send_reschedule(cpu
);
1254 EXPORT_SYMBOL_GPL(kick_process
);
1255 #endif /* CONFIG_SMP */
1259 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1261 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1263 int nid
= cpu_to_node(cpu
);
1264 const struct cpumask
*nodemask
= NULL
;
1265 enum { cpuset
, possible
, fail
} state
= cpuset
;
1269 * If the node that the cpu is on has been offlined, cpu_to_node()
1270 * will return -1. There is no cpu on the node, and we should
1271 * select the cpu on the other node.
1274 nodemask
= cpumask_of_node(nid
);
1276 /* Look for allowed, online CPU in same node. */
1277 for_each_cpu(dest_cpu
, nodemask
) {
1278 if (!cpu_online(dest_cpu
))
1280 if (!cpu_active(dest_cpu
))
1282 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1288 /* Any allowed, online CPU? */
1289 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1290 if (!cpu_online(dest_cpu
))
1292 if (!cpu_active(dest_cpu
))
1299 /* No more Mr. Nice Guy. */
1300 cpuset_cpus_allowed_fallback(p
);
1305 do_set_cpus_allowed(p
, cpu_possible_mask
);
1316 if (state
!= cpuset
) {
1318 * Don't tell them about moving exiting tasks or
1319 * kernel threads (both mm NULL), since they never
1322 if (p
->mm
&& printk_ratelimit()) {
1323 printk_sched("process %d (%s) no longer affine to cpu%d\n",
1324 task_pid_nr(p
), p
->comm
, cpu
);
1332 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1335 int select_task_rq(struct task_struct
*p
, int cpu
, int sd_flags
, int wake_flags
)
1337 cpu
= p
->sched_class
->select_task_rq(p
, cpu
, sd_flags
, wake_flags
);
1340 * In order not to call set_task_cpu() on a blocking task we need
1341 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1344 * Since this is common to all placement strategies, this lives here.
1346 * [ this allows ->select_task() to simply return task_cpu(p) and
1347 * not worry about this generic constraint ]
1349 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1351 cpu
= select_fallback_rq(task_cpu(p
), p
);
1356 static void update_avg(u64
*avg
, u64 sample
)
1358 s64 diff
= sample
- *avg
;
1364 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1366 #ifdef CONFIG_SCHEDSTATS
1367 struct rq
*rq
= this_rq();
1370 int this_cpu
= smp_processor_id();
1372 if (cpu
== this_cpu
) {
1373 schedstat_inc(rq
, ttwu_local
);
1374 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1376 struct sched_domain
*sd
;
1378 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1380 for_each_domain(this_cpu
, sd
) {
1381 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1382 schedstat_inc(sd
, ttwu_wake_remote
);
1389 if (wake_flags
& WF_MIGRATED
)
1390 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1392 #endif /* CONFIG_SMP */
1394 schedstat_inc(rq
, ttwu_count
);
1395 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1397 if (wake_flags
& WF_SYNC
)
1398 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1400 #endif /* CONFIG_SCHEDSTATS */
1403 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1405 activate_task(rq
, p
, en_flags
);
1408 /* if a worker is waking up, notify workqueue */
1409 if (p
->flags
& PF_WQ_WORKER
)
1410 wq_worker_waking_up(p
, cpu_of(rq
));
1414 * Mark the task runnable and perform wakeup-preemption.
1417 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1419 check_preempt_curr(rq
, p
, wake_flags
);
1420 trace_sched_wakeup(p
, true);
1422 p
->state
= TASK_RUNNING
;
1424 if (p
->sched_class
->task_woken
)
1425 p
->sched_class
->task_woken(rq
, p
);
1427 if (rq
->idle_stamp
) {
1428 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1429 u64 max
= 2*rq
->max_idle_balance_cost
;
1431 update_avg(&rq
->avg_idle
, delta
);
1433 if (rq
->avg_idle
> max
)
1442 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1445 if (p
->sched_contributes_to_load
)
1446 rq
->nr_uninterruptible
--;
1449 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1450 ttwu_do_wakeup(rq
, p
, wake_flags
);
1454 * Called in case the task @p isn't fully descheduled from its runqueue,
1455 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1456 * since all we need to do is flip p->state to TASK_RUNNING, since
1457 * the task is still ->on_rq.
1459 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1464 rq
= __task_rq_lock(p
);
1466 /* check_preempt_curr() may use rq clock */
1467 update_rq_clock(rq
);
1468 ttwu_do_wakeup(rq
, p
, wake_flags
);
1471 __task_rq_unlock(rq
);
1477 static void sched_ttwu_pending(void)
1479 struct rq
*rq
= this_rq();
1480 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1481 struct task_struct
*p
;
1483 raw_spin_lock(&rq
->lock
);
1486 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1487 llist
= llist_next(llist
);
1488 ttwu_do_activate(rq
, p
, 0);
1491 raw_spin_unlock(&rq
->lock
);
1494 void scheduler_ipi(void)
1497 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1498 * TIF_NEED_RESCHED remotely (for the first time) will also send
1501 preempt_fold_need_resched();
1503 if (llist_empty(&this_rq()->wake_list
)
1504 && !tick_nohz_full_cpu(smp_processor_id())
1505 && !got_nohz_idle_kick())
1509 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1510 * traditionally all their work was done from the interrupt return
1511 * path. Now that we actually do some work, we need to make sure
1514 * Some archs already do call them, luckily irq_enter/exit nest
1517 * Arguably we should visit all archs and update all handlers,
1518 * however a fair share of IPIs are still resched only so this would
1519 * somewhat pessimize the simple resched case.
1522 tick_nohz_full_check();
1523 sched_ttwu_pending();
1526 * Check if someone kicked us for doing the nohz idle load balance.
1528 if (unlikely(got_nohz_idle_kick())) {
1529 this_rq()->idle_balance
= 1;
1530 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1535 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1537 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
1538 smp_send_reschedule(cpu
);
1541 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1543 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1545 #endif /* CONFIG_SMP */
1547 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1549 struct rq
*rq
= cpu_rq(cpu
);
1551 #if defined(CONFIG_SMP)
1552 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1553 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1554 ttwu_queue_remote(p
, cpu
);
1559 raw_spin_lock(&rq
->lock
);
1560 ttwu_do_activate(rq
, p
, 0);
1561 raw_spin_unlock(&rq
->lock
);
1565 * try_to_wake_up - wake up a thread
1566 * @p: the thread to be awakened
1567 * @state: the mask of task states that can be woken
1568 * @wake_flags: wake modifier flags (WF_*)
1570 * Put it on the run-queue if it's not already there. The "current"
1571 * thread is always on the run-queue (except when the actual
1572 * re-schedule is in progress), and as such you're allowed to do
1573 * the simpler "current->state = TASK_RUNNING" to mark yourself
1574 * runnable without the overhead of this.
1576 * Return: %true if @p was woken up, %false if it was already running.
1577 * or @state didn't match @p's state.
1580 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1582 unsigned long flags
;
1583 int cpu
, success
= 0;
1586 * If we are going to wake up a thread waiting for CONDITION we
1587 * need to ensure that CONDITION=1 done by the caller can not be
1588 * reordered with p->state check below. This pairs with mb() in
1589 * set_current_state() the waiting thread does.
1591 smp_mb__before_spinlock();
1592 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1593 if (!(p
->state
& state
))
1596 success
= 1; /* we're going to change ->state */
1599 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1604 * If the owning (remote) cpu is still in the middle of schedule() with
1605 * this task as prev, wait until its done referencing the task.
1610 * Pairs with the smp_wmb() in finish_lock_switch().
1614 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1615 p
->state
= TASK_WAKING
;
1617 if (p
->sched_class
->task_waking
)
1618 p
->sched_class
->task_waking(p
);
1620 cpu
= select_task_rq(p
, p
->wake_cpu
, SD_BALANCE_WAKE
, wake_flags
);
1621 if (task_cpu(p
) != cpu
) {
1622 wake_flags
|= WF_MIGRATED
;
1623 set_task_cpu(p
, cpu
);
1625 #endif /* CONFIG_SMP */
1629 ttwu_stat(p
, cpu
, wake_flags
);
1631 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1637 * try_to_wake_up_local - try to wake up a local task with rq lock held
1638 * @p: the thread to be awakened
1640 * Put @p on the run-queue if it's not already there. The caller must
1641 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1644 static void try_to_wake_up_local(struct task_struct
*p
)
1646 struct rq
*rq
= task_rq(p
);
1648 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1649 WARN_ON_ONCE(p
== current
))
1652 lockdep_assert_held(&rq
->lock
);
1654 if (!raw_spin_trylock(&p
->pi_lock
)) {
1655 raw_spin_unlock(&rq
->lock
);
1656 raw_spin_lock(&p
->pi_lock
);
1657 raw_spin_lock(&rq
->lock
);
1660 if (!(p
->state
& TASK_NORMAL
))
1664 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1666 ttwu_do_wakeup(rq
, p
, 0);
1667 ttwu_stat(p
, smp_processor_id(), 0);
1669 raw_spin_unlock(&p
->pi_lock
);
1673 * wake_up_process - Wake up a specific process
1674 * @p: The process to be woken up.
1676 * Attempt to wake up the nominated process and move it to the set of runnable
1679 * Return: 1 if the process was woken up, 0 if it was already running.
1681 * It may be assumed that this function implies a write memory barrier before
1682 * changing the task state if and only if any tasks are woken up.
1684 int wake_up_process(struct task_struct
*p
)
1686 WARN_ON(task_is_stopped_or_traced(p
));
1687 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1689 EXPORT_SYMBOL(wake_up_process
);
1691 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1693 return try_to_wake_up(p
, state
, 0);
1697 * Perform scheduler related setup for a newly forked process p.
1698 * p is forked by current.
1700 * __sched_fork() is basic setup used by init_idle() too:
1702 static void __sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1707 p
->se
.exec_start
= 0;
1708 p
->se
.sum_exec_runtime
= 0;
1709 p
->se
.prev_sum_exec_runtime
= 0;
1710 p
->se
.nr_migrations
= 0;
1712 INIT_LIST_HEAD(&p
->se
.group_node
);
1714 #ifdef CONFIG_SCHEDSTATS
1715 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1718 RB_CLEAR_NODE(&p
->dl
.rb_node
);
1719 hrtimer_init(&p
->dl
.dl_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1720 p
->dl
.dl_runtime
= p
->dl
.runtime
= 0;
1721 p
->dl
.dl_deadline
= p
->dl
.deadline
= 0;
1722 p
->dl
.dl_period
= 0;
1725 INIT_LIST_HEAD(&p
->rt
.run_list
);
1727 #ifdef CONFIG_PREEMPT_NOTIFIERS
1728 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1731 #ifdef CONFIG_NUMA_BALANCING
1732 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1733 p
->mm
->numa_next_scan
= jiffies
+ msecs_to_jiffies(sysctl_numa_balancing_scan_delay
);
1734 p
->mm
->numa_scan_seq
= 0;
1737 if (clone_flags
& CLONE_VM
)
1738 p
->numa_preferred_nid
= current
->numa_preferred_nid
;
1740 p
->numa_preferred_nid
= -1;
1742 p
->node_stamp
= 0ULL;
1743 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1744 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1745 p
->numa_work
.next
= &p
->numa_work
;
1746 p
->numa_faults_memory
= NULL
;
1747 p
->numa_faults_buffer_memory
= NULL
;
1748 p
->last_task_numa_placement
= 0;
1749 p
->last_sum_exec_runtime
= 0;
1751 INIT_LIST_HEAD(&p
->numa_entry
);
1752 p
->numa_group
= NULL
;
1753 #endif /* CONFIG_NUMA_BALANCING */
1756 #ifdef CONFIG_NUMA_BALANCING
1757 #ifdef CONFIG_SCHED_DEBUG
1758 void set_numabalancing_state(bool enabled
)
1761 sched_feat_set("NUMA");
1763 sched_feat_set("NO_NUMA");
1766 __read_mostly
bool numabalancing_enabled
;
1768 void set_numabalancing_state(bool enabled
)
1770 numabalancing_enabled
= enabled
;
1772 #endif /* CONFIG_SCHED_DEBUG */
1774 #ifdef CONFIG_PROC_SYSCTL
1775 int sysctl_numa_balancing(struct ctl_table
*table
, int write
,
1776 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1780 int state
= numabalancing_enabled
;
1782 if (write
&& !capable(CAP_SYS_ADMIN
))
1787 err
= proc_dointvec_minmax(&t
, write
, buffer
, lenp
, ppos
);
1791 set_numabalancing_state(state
);
1798 * fork()/clone()-time setup:
1800 int sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1802 unsigned long flags
;
1803 int cpu
= get_cpu();
1805 __sched_fork(clone_flags
, p
);
1807 * We mark the process as running here. This guarantees that
1808 * nobody will actually run it, and a signal or other external
1809 * event cannot wake it up and insert it on the runqueue either.
1811 p
->state
= TASK_RUNNING
;
1814 * Make sure we do not leak PI boosting priority to the child.
1816 p
->prio
= current
->normal_prio
;
1819 * Revert to default priority/policy on fork if requested.
1821 if (unlikely(p
->sched_reset_on_fork
)) {
1822 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
1823 p
->policy
= SCHED_NORMAL
;
1824 p
->static_prio
= NICE_TO_PRIO(0);
1826 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1827 p
->static_prio
= NICE_TO_PRIO(0);
1829 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1833 * We don't need the reset flag anymore after the fork. It has
1834 * fulfilled its duty:
1836 p
->sched_reset_on_fork
= 0;
1839 if (dl_prio(p
->prio
)) {
1842 } else if (rt_prio(p
->prio
)) {
1843 p
->sched_class
= &rt_sched_class
;
1845 p
->sched_class
= &fair_sched_class
;
1848 if (p
->sched_class
->task_fork
)
1849 p
->sched_class
->task_fork(p
);
1852 * The child is not yet in the pid-hash so no cgroup attach races,
1853 * and the cgroup is pinned to this child due to cgroup_fork()
1854 * is ran before sched_fork().
1856 * Silence PROVE_RCU.
1858 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1859 set_task_cpu(p
, cpu
);
1860 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1862 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1863 if (likely(sched_info_on()))
1864 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1866 #if defined(CONFIG_SMP)
1869 init_task_preempt_count(p
);
1871 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1872 RB_CLEAR_NODE(&p
->pushable_dl_tasks
);
1879 unsigned long to_ratio(u64 period
, u64 runtime
)
1881 if (runtime
== RUNTIME_INF
)
1885 * Doing this here saves a lot of checks in all
1886 * the calling paths, and returning zero seems
1887 * safe for them anyway.
1892 return div64_u64(runtime
<< 20, period
);
1896 inline struct dl_bw
*dl_bw_of(int i
)
1898 return &cpu_rq(i
)->rd
->dl_bw
;
1901 static inline int dl_bw_cpus(int i
)
1903 struct root_domain
*rd
= cpu_rq(i
)->rd
;
1906 for_each_cpu_and(i
, rd
->span
, cpu_active_mask
)
1912 inline struct dl_bw
*dl_bw_of(int i
)
1914 return &cpu_rq(i
)->dl
.dl_bw
;
1917 static inline int dl_bw_cpus(int i
)
1924 void __dl_clear(struct dl_bw
*dl_b
, u64 tsk_bw
)
1926 dl_b
->total_bw
-= tsk_bw
;
1930 void __dl_add(struct dl_bw
*dl_b
, u64 tsk_bw
)
1932 dl_b
->total_bw
+= tsk_bw
;
1936 bool __dl_overflow(struct dl_bw
*dl_b
, int cpus
, u64 old_bw
, u64 new_bw
)
1938 return dl_b
->bw
!= -1 &&
1939 dl_b
->bw
* cpus
< dl_b
->total_bw
- old_bw
+ new_bw
;
1943 * We must be sure that accepting a new task (or allowing changing the
1944 * parameters of an existing one) is consistent with the bandwidth
1945 * constraints. If yes, this function also accordingly updates the currently
1946 * allocated bandwidth to reflect the new situation.
1948 * This function is called while holding p's rq->lock.
1950 static int dl_overflow(struct task_struct
*p
, int policy
,
1951 const struct sched_attr
*attr
)
1954 struct dl_bw
*dl_b
= dl_bw_of(task_cpu(p
));
1955 u64 period
= attr
->sched_period
?: attr
->sched_deadline
;
1956 u64 runtime
= attr
->sched_runtime
;
1957 u64 new_bw
= dl_policy(policy
) ? to_ratio(period
, runtime
) : 0;
1960 if (new_bw
== p
->dl
.dl_bw
)
1964 * Either if a task, enters, leave, or stays -deadline but changes
1965 * its parameters, we may need to update accordingly the total
1966 * allocated bandwidth of the container.
1968 raw_spin_lock(&dl_b
->lock
);
1969 cpus
= dl_bw_cpus(task_cpu(p
));
1970 if (dl_policy(policy
) && !task_has_dl_policy(p
) &&
1971 !__dl_overflow(dl_b
, cpus
, 0, new_bw
)) {
1972 __dl_add(dl_b
, new_bw
);
1974 } else if (dl_policy(policy
) && task_has_dl_policy(p
) &&
1975 !__dl_overflow(dl_b
, cpus
, p
->dl
.dl_bw
, new_bw
)) {
1976 __dl_clear(dl_b
, p
->dl
.dl_bw
);
1977 __dl_add(dl_b
, new_bw
);
1979 } else if (!dl_policy(policy
) && task_has_dl_policy(p
)) {
1980 __dl_clear(dl_b
, p
->dl
.dl_bw
);
1983 raw_spin_unlock(&dl_b
->lock
);
1988 extern void init_dl_bw(struct dl_bw
*dl_b
);
1991 * wake_up_new_task - wake up a newly created task for the first time.
1993 * This function will do some initial scheduler statistics housekeeping
1994 * that must be done for every newly created context, then puts the task
1995 * on the runqueue and wakes it.
1997 void wake_up_new_task(struct task_struct
*p
)
1999 unsigned long flags
;
2002 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2005 * Fork balancing, do it here and not earlier because:
2006 * - cpus_allowed can change in the fork path
2007 * - any previously selected cpu might disappear through hotplug
2009 set_task_cpu(p
, select_task_rq(p
, task_cpu(p
), SD_BALANCE_FORK
, 0));
2012 /* Initialize new task's runnable average */
2013 init_task_runnable_average(p
);
2014 rq
= __task_rq_lock(p
);
2015 activate_task(rq
, p
, 0);
2017 trace_sched_wakeup_new(p
, true);
2018 check_preempt_curr(rq
, p
, WF_FORK
);
2020 if (p
->sched_class
->task_woken
)
2021 p
->sched_class
->task_woken(rq
, p
);
2023 task_rq_unlock(rq
, p
, &flags
);
2026 #ifdef CONFIG_PREEMPT_NOTIFIERS
2029 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2030 * @notifier: notifier struct to register
2032 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2034 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2036 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2039 * preempt_notifier_unregister - no longer interested in preemption notifications
2040 * @notifier: notifier struct to unregister
2042 * This is safe to call from within a preemption notifier.
2044 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2046 hlist_del(¬ifier
->link
);
2048 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2050 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2052 struct preempt_notifier
*notifier
;
2054 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2055 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2059 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2060 struct task_struct
*next
)
2062 struct preempt_notifier
*notifier
;
2064 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2065 notifier
->ops
->sched_out(notifier
, next
);
2068 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2070 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2075 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2076 struct task_struct
*next
)
2080 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2083 * prepare_task_switch - prepare to switch tasks
2084 * @rq: the runqueue preparing to switch
2085 * @prev: the current task that is being switched out
2086 * @next: the task we are going to switch to.
2088 * This is called with the rq lock held and interrupts off. It must
2089 * be paired with a subsequent finish_task_switch after the context
2092 * prepare_task_switch sets up locking and calls architecture specific
2096 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2097 struct task_struct
*next
)
2099 trace_sched_switch(prev
, next
);
2100 sched_info_switch(rq
, prev
, next
);
2101 perf_event_task_sched_out(prev
, next
);
2102 fire_sched_out_preempt_notifiers(prev
, next
);
2103 prepare_lock_switch(rq
, next
);
2104 prepare_arch_switch(next
);
2108 * finish_task_switch - clean up after a task-switch
2109 * @rq: runqueue associated with task-switch
2110 * @prev: the thread we just switched away from.
2112 * finish_task_switch must be called after the context switch, paired
2113 * with a prepare_task_switch call before the context switch.
2114 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2115 * and do any other architecture-specific cleanup actions.
2117 * Note that we may have delayed dropping an mm in context_switch(). If
2118 * so, we finish that here outside of the runqueue lock. (Doing it
2119 * with the lock held can cause deadlocks; see schedule() for
2122 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2123 __releases(rq
->lock
)
2125 struct mm_struct
*mm
= rq
->prev_mm
;
2131 * A task struct has one reference for the use as "current".
2132 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2133 * schedule one last time. The schedule call will never return, and
2134 * the scheduled task must drop that reference.
2135 * The test for TASK_DEAD must occur while the runqueue locks are
2136 * still held, otherwise prev could be scheduled on another cpu, die
2137 * there before we look at prev->state, and then the reference would
2139 * Manfred Spraul <manfred@colorfullife.com>
2141 prev_state
= prev
->state
;
2142 vtime_task_switch(prev
);
2143 finish_arch_switch(prev
);
2144 perf_event_task_sched_in(prev
, current
);
2145 finish_lock_switch(rq
, prev
);
2146 finish_arch_post_lock_switch();
2148 fire_sched_in_preempt_notifiers(current
);
2151 if (unlikely(prev_state
== TASK_DEAD
)) {
2152 if (prev
->sched_class
->task_dead
)
2153 prev
->sched_class
->task_dead(prev
);
2156 * Remove function-return probe instances associated with this
2157 * task and put them back on the free list.
2159 kprobe_flush_task(prev
);
2160 put_task_struct(prev
);
2163 tick_nohz_task_switch(current
);
2168 /* rq->lock is NOT held, but preemption is disabled */
2169 static inline void post_schedule(struct rq
*rq
)
2171 if (rq
->post_schedule
) {
2172 unsigned long flags
;
2174 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2175 if (rq
->curr
->sched_class
->post_schedule
)
2176 rq
->curr
->sched_class
->post_schedule(rq
);
2177 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2179 rq
->post_schedule
= 0;
2185 static inline void post_schedule(struct rq
*rq
)
2192 * schedule_tail - first thing a freshly forked thread must call.
2193 * @prev: the thread we just switched away from.
2195 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2196 __releases(rq
->lock
)
2198 struct rq
*rq
= this_rq();
2200 finish_task_switch(rq
, prev
);
2203 * FIXME: do we need to worry about rq being invalidated by the
2208 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2209 /* In this case, finish_task_switch does not reenable preemption */
2212 if (current
->set_child_tid
)
2213 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2217 * context_switch - switch to the new MM and the new
2218 * thread's register state.
2221 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2222 struct task_struct
*next
)
2224 struct mm_struct
*mm
, *oldmm
;
2226 prepare_task_switch(rq
, prev
, next
);
2229 oldmm
= prev
->active_mm
;
2231 * For paravirt, this is coupled with an exit in switch_to to
2232 * combine the page table reload and the switch backend into
2235 arch_start_context_switch(prev
);
2238 next
->active_mm
= oldmm
;
2239 atomic_inc(&oldmm
->mm_count
);
2240 enter_lazy_tlb(oldmm
, next
);
2242 switch_mm(oldmm
, mm
, next
);
2245 prev
->active_mm
= NULL
;
2246 rq
->prev_mm
= oldmm
;
2249 * Since the runqueue lock will be released by the next
2250 * task (which is an invalid locking op but in the case
2251 * of the scheduler it's an obvious special-case), so we
2252 * do an early lockdep release here:
2254 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2255 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2258 context_tracking_task_switch(prev
, next
);
2259 /* Here we just switch the register state and the stack. */
2260 switch_to(prev
, next
, prev
);
2264 * this_rq must be evaluated again because prev may have moved
2265 * CPUs since it called schedule(), thus the 'rq' on its stack
2266 * frame will be invalid.
2268 finish_task_switch(this_rq(), prev
);
2272 * nr_running and nr_context_switches:
2274 * externally visible scheduler statistics: current number of runnable
2275 * threads, total number of context switches performed since bootup.
2277 unsigned long nr_running(void)
2279 unsigned long i
, sum
= 0;
2281 for_each_online_cpu(i
)
2282 sum
+= cpu_rq(i
)->nr_running
;
2287 unsigned long long nr_context_switches(void)
2290 unsigned long long sum
= 0;
2292 for_each_possible_cpu(i
)
2293 sum
+= cpu_rq(i
)->nr_switches
;
2298 unsigned long nr_iowait(void)
2300 unsigned long i
, sum
= 0;
2302 for_each_possible_cpu(i
)
2303 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2308 unsigned long nr_iowait_cpu(int cpu
)
2310 struct rq
*this = cpu_rq(cpu
);
2311 return atomic_read(&this->nr_iowait
);
2317 * sched_exec - execve() is a valuable balancing opportunity, because at
2318 * this point the task has the smallest effective memory and cache footprint.
2320 void sched_exec(void)
2322 struct task_struct
*p
= current
;
2323 unsigned long flags
;
2326 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2327 dest_cpu
= p
->sched_class
->select_task_rq(p
, task_cpu(p
), SD_BALANCE_EXEC
, 0);
2328 if (dest_cpu
== smp_processor_id())
2331 if (likely(cpu_active(dest_cpu
))) {
2332 struct migration_arg arg
= { p
, dest_cpu
};
2334 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2335 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2339 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2344 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2345 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2347 EXPORT_PER_CPU_SYMBOL(kstat
);
2348 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2351 * Return any ns on the sched_clock that have not yet been accounted in
2352 * @p in case that task is currently running.
2354 * Called with task_rq_lock() held on @rq.
2356 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2360 if (task_current(rq
, p
)) {
2361 update_rq_clock(rq
);
2362 ns
= rq_clock_task(rq
) - p
->se
.exec_start
;
2370 unsigned long long task_delta_exec(struct task_struct
*p
)
2372 unsigned long flags
;
2376 rq
= task_rq_lock(p
, &flags
);
2377 ns
= do_task_delta_exec(p
, rq
);
2378 task_rq_unlock(rq
, p
, &flags
);
2384 * Return accounted runtime for the task.
2385 * In case the task is currently running, return the runtime plus current's
2386 * pending runtime that have not been accounted yet.
2388 unsigned long long task_sched_runtime(struct task_struct
*p
)
2390 unsigned long flags
;
2394 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2396 * 64-bit doesn't need locks to atomically read a 64bit value.
2397 * So we have a optimization chance when the task's delta_exec is 0.
2398 * Reading ->on_cpu is racy, but this is ok.
2400 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2401 * If we race with it entering cpu, unaccounted time is 0. This is
2402 * indistinguishable from the read occurring a few cycles earlier.
2405 return p
->se
.sum_exec_runtime
;
2408 rq
= task_rq_lock(p
, &flags
);
2409 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2410 task_rq_unlock(rq
, p
, &flags
);
2416 * This function gets called by the timer code, with HZ frequency.
2417 * We call it with interrupts disabled.
2419 void scheduler_tick(void)
2421 int cpu
= smp_processor_id();
2422 struct rq
*rq
= cpu_rq(cpu
);
2423 struct task_struct
*curr
= rq
->curr
;
2427 raw_spin_lock(&rq
->lock
);
2428 update_rq_clock(rq
);
2429 curr
->sched_class
->task_tick(rq
, curr
, 0);
2430 update_cpu_load_active(rq
);
2431 raw_spin_unlock(&rq
->lock
);
2433 perf_event_task_tick();
2436 rq
->idle_balance
= idle_cpu(cpu
);
2437 trigger_load_balance(rq
);
2439 rq_last_tick_reset(rq
);
2442 #ifdef CONFIG_NO_HZ_FULL
2444 * scheduler_tick_max_deferment
2446 * Keep at least one tick per second when a single
2447 * active task is running because the scheduler doesn't
2448 * yet completely support full dynticks environment.
2450 * This makes sure that uptime, CFS vruntime, load
2451 * balancing, etc... continue to move forward, even
2452 * with a very low granularity.
2454 * Return: Maximum deferment in nanoseconds.
2456 u64
scheduler_tick_max_deferment(void)
2458 struct rq
*rq
= this_rq();
2459 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2461 next
= rq
->last_sched_tick
+ HZ
;
2463 if (time_before_eq(next
, now
))
2466 return jiffies_to_nsecs(next
- now
);
2470 notrace
unsigned long get_parent_ip(unsigned long addr
)
2472 if (in_lock_functions(addr
)) {
2473 addr
= CALLER_ADDR2
;
2474 if (in_lock_functions(addr
))
2475 addr
= CALLER_ADDR3
;
2480 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2481 defined(CONFIG_PREEMPT_TRACER))
2483 void __kprobes
preempt_count_add(int val
)
2485 #ifdef CONFIG_DEBUG_PREEMPT
2489 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2492 __preempt_count_add(val
);
2493 #ifdef CONFIG_DEBUG_PREEMPT
2495 * Spinlock count overflowing soon?
2497 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2500 if (preempt_count() == val
) {
2501 unsigned long ip
= get_parent_ip(CALLER_ADDR1
);
2502 #ifdef CONFIG_DEBUG_PREEMPT
2503 current
->preempt_disable_ip
= ip
;
2505 trace_preempt_off(CALLER_ADDR0
, ip
);
2508 EXPORT_SYMBOL(preempt_count_add
);
2510 void __kprobes
preempt_count_sub(int val
)
2512 #ifdef CONFIG_DEBUG_PREEMPT
2516 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2519 * Is the spinlock portion underflowing?
2521 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2522 !(preempt_count() & PREEMPT_MASK
)))
2526 if (preempt_count() == val
)
2527 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2528 __preempt_count_sub(val
);
2530 EXPORT_SYMBOL(preempt_count_sub
);
2535 * Print scheduling while atomic bug:
2537 static noinline
void __schedule_bug(struct task_struct
*prev
)
2539 if (oops_in_progress
)
2542 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2543 prev
->comm
, prev
->pid
, preempt_count());
2545 debug_show_held_locks(prev
);
2547 if (irqs_disabled())
2548 print_irqtrace_events(prev
);
2549 #ifdef CONFIG_DEBUG_PREEMPT
2550 if (in_atomic_preempt_off()) {
2551 pr_err("Preemption disabled at:");
2552 print_ip_sym(current
->preempt_disable_ip
);
2557 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2561 * Various schedule()-time debugging checks and statistics:
2563 static inline void schedule_debug(struct task_struct
*prev
)
2566 * Test if we are atomic. Since do_exit() needs to call into
2567 * schedule() atomically, we ignore that path. Otherwise whine
2568 * if we are scheduling when we should not.
2570 if (unlikely(in_atomic_preempt_off() && prev
->state
!= TASK_DEAD
))
2571 __schedule_bug(prev
);
2574 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2576 schedstat_inc(this_rq(), sched_count
);
2580 * Pick up the highest-prio task:
2582 static inline struct task_struct
*
2583 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
2585 const struct sched_class
*class = &fair_sched_class
;
2586 struct task_struct
*p
;
2589 * Optimization: we know that if all tasks are in
2590 * the fair class we can call that function directly:
2592 if (likely(prev
->sched_class
== class &&
2593 rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2594 p
= fair_sched_class
.pick_next_task(rq
, prev
);
2595 if (unlikely(p
== RETRY_TASK
))
2598 /* assumes fair_sched_class->next == idle_sched_class */
2600 p
= idle_sched_class
.pick_next_task(rq
, prev
);
2606 for_each_class(class) {
2607 p
= class->pick_next_task(rq
, prev
);
2609 if (unlikely(p
== RETRY_TASK
))
2615 BUG(); /* the idle class will always have a runnable task */
2619 * __schedule() is the main scheduler function.
2621 * The main means of driving the scheduler and thus entering this function are:
2623 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2625 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2626 * paths. For example, see arch/x86/entry_64.S.
2628 * To drive preemption between tasks, the scheduler sets the flag in timer
2629 * interrupt handler scheduler_tick().
2631 * 3. Wakeups don't really cause entry into schedule(). They add a
2632 * task to the run-queue and that's it.
2634 * Now, if the new task added to the run-queue preempts the current
2635 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2636 * called on the nearest possible occasion:
2638 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2640 * - in syscall or exception context, at the next outmost
2641 * preempt_enable(). (this might be as soon as the wake_up()'s
2644 * - in IRQ context, return from interrupt-handler to
2645 * preemptible context
2647 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2650 * - cond_resched() call
2651 * - explicit schedule() call
2652 * - return from syscall or exception to user-space
2653 * - return from interrupt-handler to user-space
2655 static void __sched
__schedule(void)
2657 struct task_struct
*prev
, *next
;
2658 unsigned long *switch_count
;
2664 cpu
= smp_processor_id();
2666 rcu_note_context_switch(cpu
);
2669 schedule_debug(prev
);
2671 if (sched_feat(HRTICK
))
2675 * Make sure that signal_pending_state()->signal_pending() below
2676 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2677 * done by the caller to avoid the race with signal_wake_up().
2679 smp_mb__before_spinlock();
2680 raw_spin_lock_irq(&rq
->lock
);
2682 switch_count
= &prev
->nivcsw
;
2683 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2684 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2685 prev
->state
= TASK_RUNNING
;
2687 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2691 * If a worker went to sleep, notify and ask workqueue
2692 * whether it wants to wake up a task to maintain
2695 if (prev
->flags
& PF_WQ_WORKER
) {
2696 struct task_struct
*to_wakeup
;
2698 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2700 try_to_wake_up_local(to_wakeup
);
2703 switch_count
= &prev
->nvcsw
;
2706 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
2707 update_rq_clock(rq
);
2709 next
= pick_next_task(rq
, prev
);
2710 clear_tsk_need_resched(prev
);
2711 clear_preempt_need_resched();
2712 rq
->skip_clock_update
= 0;
2714 if (likely(prev
!= next
)) {
2719 context_switch(rq
, prev
, next
); /* unlocks the rq */
2721 * The context switch have flipped the stack from under us
2722 * and restored the local variables which were saved when
2723 * this task called schedule() in the past. prev == current
2724 * is still correct, but it can be moved to another cpu/rq.
2726 cpu
= smp_processor_id();
2729 raw_spin_unlock_irq(&rq
->lock
);
2733 sched_preempt_enable_no_resched();
2738 static inline void sched_submit_work(struct task_struct
*tsk
)
2740 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2743 * If we are going to sleep and we have plugged IO queued,
2744 * make sure to submit it to avoid deadlocks.
2746 if (blk_needs_flush_plug(tsk
))
2747 blk_schedule_flush_plug(tsk
);
2750 asmlinkage
void __sched
schedule(void)
2752 struct task_struct
*tsk
= current
;
2754 sched_submit_work(tsk
);
2757 EXPORT_SYMBOL(schedule
);
2759 #ifdef CONFIG_CONTEXT_TRACKING
2760 asmlinkage
void __sched
schedule_user(void)
2763 * If we come here after a random call to set_need_resched(),
2764 * or we have been woken up remotely but the IPI has not yet arrived,
2765 * we haven't yet exited the RCU idle mode. Do it here manually until
2766 * we find a better solution.
2775 * schedule_preempt_disabled - called with preemption disabled
2777 * Returns with preemption disabled. Note: preempt_count must be 1
2779 void __sched
schedule_preempt_disabled(void)
2781 sched_preempt_enable_no_resched();
2786 #ifdef CONFIG_PREEMPT
2788 * this is the entry point to schedule() from in-kernel preemption
2789 * off of preempt_enable. Kernel preemptions off return from interrupt
2790 * occur there and call schedule directly.
2792 asmlinkage
void __sched notrace
preempt_schedule(void)
2795 * If there is a non-zero preempt_count or interrupts are disabled,
2796 * we do not want to preempt the current task. Just return..
2798 if (likely(!preemptible()))
2802 __preempt_count_add(PREEMPT_ACTIVE
);
2804 __preempt_count_sub(PREEMPT_ACTIVE
);
2807 * Check again in case we missed a preemption opportunity
2808 * between schedule and now.
2811 } while (need_resched());
2813 EXPORT_SYMBOL(preempt_schedule
);
2814 #endif /* CONFIG_PREEMPT */
2817 * this is the entry point to schedule() from kernel preemption
2818 * off of irq context.
2819 * Note, that this is called and return with irqs disabled. This will
2820 * protect us against recursive calling from irq.
2822 asmlinkage
void __sched
preempt_schedule_irq(void)
2824 enum ctx_state prev_state
;
2826 /* Catch callers which need to be fixed */
2827 BUG_ON(preempt_count() || !irqs_disabled());
2829 prev_state
= exception_enter();
2832 __preempt_count_add(PREEMPT_ACTIVE
);
2835 local_irq_disable();
2836 __preempt_count_sub(PREEMPT_ACTIVE
);
2839 * Check again in case we missed a preemption opportunity
2840 * between schedule and now.
2843 } while (need_resched());
2845 exception_exit(prev_state
);
2848 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2851 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2853 EXPORT_SYMBOL(default_wake_function
);
2855 #ifdef CONFIG_RT_MUTEXES
2858 * rt_mutex_setprio - set the current priority of a task
2860 * @prio: prio value (kernel-internal form)
2862 * This function changes the 'effective' priority of a task. It does
2863 * not touch ->normal_prio like __setscheduler().
2865 * Used by the rt_mutex code to implement priority inheritance
2866 * logic. Call site only calls if the priority of the task changed.
2868 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
2870 int oldprio
, on_rq
, running
, enqueue_flag
= 0;
2872 const struct sched_class
*prev_class
;
2874 BUG_ON(prio
> MAX_PRIO
);
2876 rq
= __task_rq_lock(p
);
2879 * Idle task boosting is a nono in general. There is one
2880 * exception, when PREEMPT_RT and NOHZ is active:
2882 * The idle task calls get_next_timer_interrupt() and holds
2883 * the timer wheel base->lock on the CPU and another CPU wants
2884 * to access the timer (probably to cancel it). We can safely
2885 * ignore the boosting request, as the idle CPU runs this code
2886 * with interrupts disabled and will complete the lock
2887 * protected section without being interrupted. So there is no
2888 * real need to boost.
2890 if (unlikely(p
== rq
->idle
)) {
2891 WARN_ON(p
!= rq
->curr
);
2892 WARN_ON(p
->pi_blocked_on
);
2896 trace_sched_pi_setprio(p
, prio
);
2897 p
->pi_top_task
= rt_mutex_get_top_task(p
);
2899 prev_class
= p
->sched_class
;
2901 running
= task_current(rq
, p
);
2903 dequeue_task(rq
, p
, 0);
2905 p
->sched_class
->put_prev_task(rq
, p
);
2908 * Boosting condition are:
2909 * 1. -rt task is running and holds mutex A
2910 * --> -dl task blocks on mutex A
2912 * 2. -dl task is running and holds mutex A
2913 * --> -dl task blocks on mutex A and could preempt the
2916 if (dl_prio(prio
)) {
2917 if (!dl_prio(p
->normal_prio
) || (p
->pi_top_task
&&
2918 dl_entity_preempt(&p
->pi_top_task
->dl
, &p
->dl
))) {
2919 p
->dl
.dl_boosted
= 1;
2920 p
->dl
.dl_throttled
= 0;
2921 enqueue_flag
= ENQUEUE_REPLENISH
;
2923 p
->dl
.dl_boosted
= 0;
2924 p
->sched_class
= &dl_sched_class
;
2925 } else if (rt_prio(prio
)) {
2926 if (dl_prio(oldprio
))
2927 p
->dl
.dl_boosted
= 0;
2929 enqueue_flag
= ENQUEUE_HEAD
;
2930 p
->sched_class
= &rt_sched_class
;
2932 if (dl_prio(oldprio
))
2933 p
->dl
.dl_boosted
= 0;
2934 p
->sched_class
= &fair_sched_class
;
2940 p
->sched_class
->set_curr_task(rq
);
2942 enqueue_task(rq
, p
, enqueue_flag
);
2944 check_class_changed(rq
, p
, prev_class
, oldprio
);
2946 __task_rq_unlock(rq
);
2950 void set_user_nice(struct task_struct
*p
, long nice
)
2952 int old_prio
, delta
, on_rq
;
2953 unsigned long flags
;
2956 if (task_nice(p
) == nice
|| nice
< MIN_NICE
|| nice
> MAX_NICE
)
2959 * We have to be careful, if called from sys_setpriority(),
2960 * the task might be in the middle of scheduling on another CPU.
2962 rq
= task_rq_lock(p
, &flags
);
2964 * The RT priorities are set via sched_setscheduler(), but we still
2965 * allow the 'normal' nice value to be set - but as expected
2966 * it wont have any effect on scheduling until the task is
2967 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
2969 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
2970 p
->static_prio
= NICE_TO_PRIO(nice
);
2975 dequeue_task(rq
, p
, 0);
2977 p
->static_prio
= NICE_TO_PRIO(nice
);
2980 p
->prio
= effective_prio(p
);
2981 delta
= p
->prio
- old_prio
;
2984 enqueue_task(rq
, p
, 0);
2986 * If the task increased its priority or is running and
2987 * lowered its priority, then reschedule its CPU:
2989 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
2990 resched_task(rq
->curr
);
2993 task_rq_unlock(rq
, p
, &flags
);
2995 EXPORT_SYMBOL(set_user_nice
);
2998 * can_nice - check if a task can reduce its nice value
3002 int can_nice(const struct task_struct
*p
, const int nice
)
3004 /* convert nice value [19,-20] to rlimit style value [1,40] */
3005 int nice_rlim
= 20 - nice
;
3007 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3008 capable(CAP_SYS_NICE
));
3011 #ifdef __ARCH_WANT_SYS_NICE
3014 * sys_nice - change the priority of the current process.
3015 * @increment: priority increment
3017 * sys_setpriority is a more generic, but much slower function that
3018 * does similar things.
3020 SYSCALL_DEFINE1(nice
, int, increment
)
3025 * Setpriority might change our priority at the same moment.
3026 * We don't have to worry. Conceptually one call occurs first
3027 * and we have a single winner.
3029 if (increment
< -40)
3034 nice
= task_nice(current
) + increment
;
3035 if (nice
< MIN_NICE
)
3037 if (nice
> MAX_NICE
)
3040 if (increment
< 0 && !can_nice(current
, nice
))
3043 retval
= security_task_setnice(current
, nice
);
3047 set_user_nice(current
, nice
);
3054 * task_prio - return the priority value of a given task.
3055 * @p: the task in question.
3057 * Return: The priority value as seen by users in /proc.
3058 * RT tasks are offset by -200. Normal tasks are centered
3059 * around 0, value goes from -16 to +15.
3061 int task_prio(const struct task_struct
*p
)
3063 return p
->prio
- MAX_RT_PRIO
;
3067 * idle_cpu - is a given cpu idle currently?
3068 * @cpu: the processor in question.
3070 * Return: 1 if the CPU is currently idle. 0 otherwise.
3072 int idle_cpu(int cpu
)
3074 struct rq
*rq
= cpu_rq(cpu
);
3076 if (rq
->curr
!= rq
->idle
)
3083 if (!llist_empty(&rq
->wake_list
))
3091 * idle_task - return the idle task for a given cpu.
3092 * @cpu: the processor in question.
3094 * Return: The idle task for the cpu @cpu.
3096 struct task_struct
*idle_task(int cpu
)
3098 return cpu_rq(cpu
)->idle
;
3102 * find_process_by_pid - find a process with a matching PID value.
3103 * @pid: the pid in question.
3105 * The task of @pid, if found. %NULL otherwise.
3107 static struct task_struct
*find_process_by_pid(pid_t pid
)
3109 return pid
? find_task_by_vpid(pid
) : current
;
3113 * This function initializes the sched_dl_entity of a newly becoming
3114 * SCHED_DEADLINE task.
3116 * Only the static values are considered here, the actual runtime and the
3117 * absolute deadline will be properly calculated when the task is enqueued
3118 * for the first time with its new policy.
3121 __setparam_dl(struct task_struct
*p
, const struct sched_attr
*attr
)
3123 struct sched_dl_entity
*dl_se
= &p
->dl
;
3125 init_dl_task_timer(dl_se
);
3126 dl_se
->dl_runtime
= attr
->sched_runtime
;
3127 dl_se
->dl_deadline
= attr
->sched_deadline
;
3128 dl_se
->dl_period
= attr
->sched_period
?: dl_se
->dl_deadline
;
3129 dl_se
->flags
= attr
->sched_flags
;
3130 dl_se
->dl_bw
= to_ratio(dl_se
->dl_period
, dl_se
->dl_runtime
);
3131 dl_se
->dl_throttled
= 0;
3133 dl_se
->dl_yielded
= 0;
3136 static void __setscheduler_params(struct task_struct
*p
,
3137 const struct sched_attr
*attr
)
3139 int policy
= attr
->sched_policy
;
3141 if (policy
== -1) /* setparam */
3146 if (dl_policy(policy
))
3147 __setparam_dl(p
, attr
);
3148 else if (fair_policy(policy
))
3149 p
->static_prio
= NICE_TO_PRIO(attr
->sched_nice
);
3152 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3153 * !rt_policy. Always setting this ensures that things like
3154 * getparam()/getattr() don't report silly values for !rt tasks.
3156 p
->rt_priority
= attr
->sched_priority
;
3157 p
->normal_prio
= normal_prio(p
);
3161 /* Actually do priority change: must hold pi & rq lock. */
3162 static void __setscheduler(struct rq
*rq
, struct task_struct
*p
,
3163 const struct sched_attr
*attr
)
3165 __setscheduler_params(p
, attr
);
3168 * If we get here, there was no pi waiters boosting the
3169 * task. It is safe to use the normal prio.
3171 p
->prio
= normal_prio(p
);
3173 if (dl_prio(p
->prio
))
3174 p
->sched_class
= &dl_sched_class
;
3175 else if (rt_prio(p
->prio
))
3176 p
->sched_class
= &rt_sched_class
;
3178 p
->sched_class
= &fair_sched_class
;
3182 __getparam_dl(struct task_struct
*p
, struct sched_attr
*attr
)
3184 struct sched_dl_entity
*dl_se
= &p
->dl
;
3186 attr
->sched_priority
= p
->rt_priority
;
3187 attr
->sched_runtime
= dl_se
->dl_runtime
;
3188 attr
->sched_deadline
= dl_se
->dl_deadline
;
3189 attr
->sched_period
= dl_se
->dl_period
;
3190 attr
->sched_flags
= dl_se
->flags
;
3194 * This function validates the new parameters of a -deadline task.
3195 * We ask for the deadline not being zero, and greater or equal
3196 * than the runtime, as well as the period of being zero or
3197 * greater than deadline. Furthermore, we have to be sure that
3198 * user parameters are above the internal resolution of 1us (we
3199 * check sched_runtime only since it is always the smaller one) and
3200 * below 2^63 ns (we have to check both sched_deadline and
3201 * sched_period, as the latter can be zero).
3204 __checkparam_dl(const struct sched_attr
*attr
)
3207 if (attr
->sched_deadline
== 0)
3211 * Since we truncate DL_SCALE bits, make sure we're at least
3214 if (attr
->sched_runtime
< (1ULL << DL_SCALE
))
3218 * Since we use the MSB for wrap-around and sign issues, make
3219 * sure it's not set (mind that period can be equal to zero).
3221 if (attr
->sched_deadline
& (1ULL << 63) ||
3222 attr
->sched_period
& (1ULL << 63))
3225 /* runtime <= deadline <= period (if period != 0) */
3226 if ((attr
->sched_period
!= 0 &&
3227 attr
->sched_period
< attr
->sched_deadline
) ||
3228 attr
->sched_deadline
< attr
->sched_runtime
)
3235 * check the target process has a UID that matches the current process's
3237 static bool check_same_owner(struct task_struct
*p
)
3239 const struct cred
*cred
= current_cred(), *pcred
;
3243 pcred
= __task_cred(p
);
3244 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3245 uid_eq(cred
->euid
, pcred
->uid
));
3250 static int __sched_setscheduler(struct task_struct
*p
,
3251 const struct sched_attr
*attr
,
3254 int newprio
= dl_policy(attr
->sched_policy
) ? MAX_DL_PRIO
- 1 :
3255 MAX_RT_PRIO
- 1 - attr
->sched_priority
;
3256 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
3257 int policy
= attr
->sched_policy
;
3258 unsigned long flags
;
3259 const struct sched_class
*prev_class
;
3263 /* may grab non-irq protected spin_locks */
3264 BUG_ON(in_interrupt());
3266 /* double check policy once rq lock held */
3268 reset_on_fork
= p
->sched_reset_on_fork
;
3269 policy
= oldpolicy
= p
->policy
;
3271 reset_on_fork
= !!(attr
->sched_flags
& SCHED_FLAG_RESET_ON_FORK
);
3273 if (policy
!= SCHED_DEADLINE
&&
3274 policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3275 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3276 policy
!= SCHED_IDLE
)
3280 if (attr
->sched_flags
& ~(SCHED_FLAG_RESET_ON_FORK
))
3284 * Valid priorities for SCHED_FIFO and SCHED_RR are
3285 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3286 * SCHED_BATCH and SCHED_IDLE is 0.
3288 if ((p
->mm
&& attr
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3289 (!p
->mm
&& attr
->sched_priority
> MAX_RT_PRIO
-1))
3291 if ((dl_policy(policy
) && !__checkparam_dl(attr
)) ||
3292 (rt_policy(policy
) != (attr
->sched_priority
!= 0)))
3296 * Allow unprivileged RT tasks to decrease priority:
3298 if (user
&& !capable(CAP_SYS_NICE
)) {
3299 if (fair_policy(policy
)) {
3300 if (attr
->sched_nice
< task_nice(p
) &&
3301 !can_nice(p
, attr
->sched_nice
))
3305 if (rt_policy(policy
)) {
3306 unsigned long rlim_rtprio
=
3307 task_rlimit(p
, RLIMIT_RTPRIO
);
3309 /* can't set/change the rt policy */
3310 if (policy
!= p
->policy
&& !rlim_rtprio
)
3313 /* can't increase priority */
3314 if (attr
->sched_priority
> p
->rt_priority
&&
3315 attr
->sched_priority
> rlim_rtprio
)
3320 * Can't set/change SCHED_DEADLINE policy at all for now
3321 * (safest behavior); in the future we would like to allow
3322 * unprivileged DL tasks to increase their relative deadline
3323 * or reduce their runtime (both ways reducing utilization)
3325 if (dl_policy(policy
))
3329 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3330 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3332 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3333 if (!can_nice(p
, task_nice(p
)))
3337 /* can't change other user's priorities */
3338 if (!check_same_owner(p
))
3341 /* Normal users shall not reset the sched_reset_on_fork flag */
3342 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3347 retval
= security_task_setscheduler(p
);
3353 * make sure no PI-waiters arrive (or leave) while we are
3354 * changing the priority of the task:
3356 * To be able to change p->policy safely, the appropriate
3357 * runqueue lock must be held.
3359 rq
= task_rq_lock(p
, &flags
);
3362 * Changing the policy of the stop threads its a very bad idea
3364 if (p
== rq
->stop
) {
3365 task_rq_unlock(rq
, p
, &flags
);
3370 * If not changing anything there's no need to proceed further,
3371 * but store a possible modification of reset_on_fork.
3373 if (unlikely(policy
== p
->policy
)) {
3374 if (fair_policy(policy
) && attr
->sched_nice
!= task_nice(p
))
3376 if (rt_policy(policy
) && attr
->sched_priority
!= p
->rt_priority
)
3378 if (dl_policy(policy
))
3381 p
->sched_reset_on_fork
= reset_on_fork
;
3382 task_rq_unlock(rq
, p
, &flags
);
3388 #ifdef CONFIG_RT_GROUP_SCHED
3390 * Do not allow realtime tasks into groups that have no runtime
3393 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3394 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3395 !task_group_is_autogroup(task_group(p
))) {
3396 task_rq_unlock(rq
, p
, &flags
);
3401 if (dl_bandwidth_enabled() && dl_policy(policy
)) {
3402 cpumask_t
*span
= rq
->rd
->span
;
3405 * Don't allow tasks with an affinity mask smaller than
3406 * the entire root_domain to become SCHED_DEADLINE. We
3407 * will also fail if there's no bandwidth available.
3409 if (!cpumask_subset(span
, &p
->cpus_allowed
) ||
3410 rq
->rd
->dl_bw
.bw
== 0) {
3411 task_rq_unlock(rq
, p
, &flags
);
3418 /* recheck policy now with rq lock held */
3419 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3420 policy
= oldpolicy
= -1;
3421 task_rq_unlock(rq
, p
, &flags
);
3426 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3427 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3430 if ((dl_policy(policy
) || dl_task(p
)) && dl_overflow(p
, policy
, attr
)) {
3431 task_rq_unlock(rq
, p
, &flags
);
3435 p
->sched_reset_on_fork
= reset_on_fork
;
3439 * Special case for priority boosted tasks.
3441 * If the new priority is lower or equal (user space view)
3442 * than the current (boosted) priority, we just store the new
3443 * normal parameters and do not touch the scheduler class and
3444 * the runqueue. This will be done when the task deboost
3447 if (rt_mutex_check_prio(p
, newprio
)) {
3448 __setscheduler_params(p
, attr
);
3449 task_rq_unlock(rq
, p
, &flags
);
3454 running
= task_current(rq
, p
);
3456 dequeue_task(rq
, p
, 0);
3458 p
->sched_class
->put_prev_task(rq
, p
);
3460 prev_class
= p
->sched_class
;
3461 __setscheduler(rq
, p
, attr
);
3464 p
->sched_class
->set_curr_task(rq
);
3467 * We enqueue to tail when the priority of a task is
3468 * increased (user space view).
3470 enqueue_task(rq
, p
, oldprio
<= p
->prio
? ENQUEUE_HEAD
: 0);
3473 check_class_changed(rq
, p
, prev_class
, oldprio
);
3474 task_rq_unlock(rq
, p
, &flags
);
3476 rt_mutex_adjust_pi(p
);
3481 static int _sched_setscheduler(struct task_struct
*p
, int policy
,
3482 const struct sched_param
*param
, bool check
)
3484 struct sched_attr attr
= {
3485 .sched_policy
= policy
,
3486 .sched_priority
= param
->sched_priority
,
3487 .sched_nice
= PRIO_TO_NICE(p
->static_prio
),
3491 * Fixup the legacy SCHED_RESET_ON_FORK hack
3493 if (policy
& SCHED_RESET_ON_FORK
) {
3494 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3495 policy
&= ~SCHED_RESET_ON_FORK
;
3496 attr
.sched_policy
= policy
;
3499 return __sched_setscheduler(p
, &attr
, check
);
3502 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3503 * @p: the task in question.
3504 * @policy: new policy.
3505 * @param: structure containing the new RT priority.
3507 * Return: 0 on success. An error code otherwise.
3509 * NOTE that the task may be already dead.
3511 int sched_setscheduler(struct task_struct
*p
, int policy
,
3512 const struct sched_param
*param
)
3514 return _sched_setscheduler(p
, policy
, param
, true);
3516 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3518 int sched_setattr(struct task_struct
*p
, const struct sched_attr
*attr
)
3520 return __sched_setscheduler(p
, attr
, true);
3522 EXPORT_SYMBOL_GPL(sched_setattr
);
3525 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3526 * @p: the task in question.
3527 * @policy: new policy.
3528 * @param: structure containing the new RT priority.
3530 * Just like sched_setscheduler, only don't bother checking if the
3531 * current context has permission. For example, this is needed in
3532 * stop_machine(): we create temporary high priority worker threads,
3533 * but our caller might not have that capability.
3535 * Return: 0 on success. An error code otherwise.
3537 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3538 const struct sched_param
*param
)
3540 return _sched_setscheduler(p
, policy
, param
, false);
3544 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3546 struct sched_param lparam
;
3547 struct task_struct
*p
;
3550 if (!param
|| pid
< 0)
3552 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3557 p
= find_process_by_pid(pid
);
3559 retval
= sched_setscheduler(p
, policy
, &lparam
);
3566 * Mimics kernel/events/core.c perf_copy_attr().
3568 static int sched_copy_attr(struct sched_attr __user
*uattr
,
3569 struct sched_attr
*attr
)
3574 if (!access_ok(VERIFY_WRITE
, uattr
, SCHED_ATTR_SIZE_VER0
))
3578 * zero the full structure, so that a short copy will be nice.
3580 memset(attr
, 0, sizeof(*attr
));
3582 ret
= get_user(size
, &uattr
->size
);
3586 if (size
> PAGE_SIZE
) /* silly large */
3589 if (!size
) /* abi compat */
3590 size
= SCHED_ATTR_SIZE_VER0
;
3592 if (size
< SCHED_ATTR_SIZE_VER0
)
3596 * If we're handed a bigger struct than we know of,
3597 * ensure all the unknown bits are 0 - i.e. new
3598 * user-space does not rely on any kernel feature
3599 * extensions we dont know about yet.
3601 if (size
> sizeof(*attr
)) {
3602 unsigned char __user
*addr
;
3603 unsigned char __user
*end
;
3606 addr
= (void __user
*)uattr
+ sizeof(*attr
);
3607 end
= (void __user
*)uattr
+ size
;
3609 for (; addr
< end
; addr
++) {
3610 ret
= get_user(val
, addr
);
3616 size
= sizeof(*attr
);
3619 ret
= copy_from_user(attr
, uattr
, size
);
3624 * XXX: do we want to be lenient like existing syscalls; or do we want
3625 * to be strict and return an error on out-of-bounds values?
3627 attr
->sched_nice
= clamp(attr
->sched_nice
, MIN_NICE
, MAX_NICE
);
3633 put_user(sizeof(*attr
), &uattr
->size
);
3639 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3640 * @pid: the pid in question.
3641 * @policy: new policy.
3642 * @param: structure containing the new RT priority.
3644 * Return: 0 on success. An error code otherwise.
3646 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3647 struct sched_param __user
*, param
)
3649 /* negative values for policy are not valid */
3653 return do_sched_setscheduler(pid
, policy
, param
);
3657 * sys_sched_setparam - set/change the RT priority of a thread
3658 * @pid: the pid in question.
3659 * @param: structure containing the new RT priority.
3661 * Return: 0 on success. An error code otherwise.
3663 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3665 return do_sched_setscheduler(pid
, -1, param
);
3669 * sys_sched_setattr - same as above, but with extended sched_attr
3670 * @pid: the pid in question.
3671 * @uattr: structure containing the extended parameters.
3672 * @flags: for future extension.
3674 SYSCALL_DEFINE3(sched_setattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3675 unsigned int, flags
)
3677 struct sched_attr attr
;
3678 struct task_struct
*p
;
3681 if (!uattr
|| pid
< 0 || flags
)
3684 retval
= sched_copy_attr(uattr
, &attr
);
3688 if (attr
.sched_policy
< 0)
3693 p
= find_process_by_pid(pid
);
3695 retval
= sched_setattr(p
, &attr
);
3702 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3703 * @pid: the pid in question.
3705 * Return: On success, the policy of the thread. Otherwise, a negative error
3708 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3710 struct task_struct
*p
;
3718 p
= find_process_by_pid(pid
);
3720 retval
= security_task_getscheduler(p
);
3723 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3730 * sys_sched_getparam - get the RT priority of a thread
3731 * @pid: the pid in question.
3732 * @param: structure containing the RT priority.
3734 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3737 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3739 struct sched_param lp
= { .sched_priority
= 0 };
3740 struct task_struct
*p
;
3743 if (!param
|| pid
< 0)
3747 p
= find_process_by_pid(pid
);
3752 retval
= security_task_getscheduler(p
);
3756 if (task_has_rt_policy(p
))
3757 lp
.sched_priority
= p
->rt_priority
;
3761 * This one might sleep, we cannot do it with a spinlock held ...
3763 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3772 static int sched_read_attr(struct sched_attr __user
*uattr
,
3773 struct sched_attr
*attr
,
3778 if (!access_ok(VERIFY_WRITE
, uattr
, usize
))
3782 * If we're handed a smaller struct than we know of,
3783 * ensure all the unknown bits are 0 - i.e. old
3784 * user-space does not get uncomplete information.
3786 if (usize
< sizeof(*attr
)) {
3787 unsigned char *addr
;
3790 addr
= (void *)attr
+ usize
;
3791 end
= (void *)attr
+ sizeof(*attr
);
3793 for (; addr
< end
; addr
++) {
3801 ret
= copy_to_user(uattr
, attr
, attr
->size
);
3814 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
3815 * @pid: the pid in question.
3816 * @uattr: structure containing the extended parameters.
3817 * @size: sizeof(attr) for fwd/bwd comp.
3818 * @flags: for future extension.
3820 SYSCALL_DEFINE4(sched_getattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3821 unsigned int, size
, unsigned int, flags
)
3823 struct sched_attr attr
= {
3824 .size
= sizeof(struct sched_attr
),
3826 struct task_struct
*p
;
3829 if (!uattr
|| pid
< 0 || size
> PAGE_SIZE
||
3830 size
< SCHED_ATTR_SIZE_VER0
|| flags
)
3834 p
= find_process_by_pid(pid
);
3839 retval
= security_task_getscheduler(p
);
3843 attr
.sched_policy
= p
->policy
;
3844 if (p
->sched_reset_on_fork
)
3845 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3846 if (task_has_dl_policy(p
))
3847 __getparam_dl(p
, &attr
);
3848 else if (task_has_rt_policy(p
))
3849 attr
.sched_priority
= p
->rt_priority
;
3851 attr
.sched_nice
= task_nice(p
);
3855 retval
= sched_read_attr(uattr
, &attr
, size
);
3863 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
3865 cpumask_var_t cpus_allowed
, new_mask
;
3866 struct task_struct
*p
;
3871 p
= find_process_by_pid(pid
);
3877 /* Prevent p going away */
3881 if (p
->flags
& PF_NO_SETAFFINITY
) {
3885 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
3889 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
3891 goto out_free_cpus_allowed
;
3894 if (!check_same_owner(p
)) {
3896 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
3903 retval
= security_task_setscheduler(p
);
3908 cpuset_cpus_allowed(p
, cpus_allowed
);
3909 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
3912 * Since bandwidth control happens on root_domain basis,
3913 * if admission test is enabled, we only admit -deadline
3914 * tasks allowed to run on all the CPUs in the task's
3918 if (task_has_dl_policy(p
)) {
3919 const struct cpumask
*span
= task_rq(p
)->rd
->span
;
3921 if (dl_bandwidth_enabled() && !cpumask_subset(span
, new_mask
)) {
3928 retval
= set_cpus_allowed_ptr(p
, new_mask
);
3931 cpuset_cpus_allowed(p
, cpus_allowed
);
3932 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
3934 * We must have raced with a concurrent cpuset
3935 * update. Just reset the cpus_allowed to the
3936 * cpuset's cpus_allowed
3938 cpumask_copy(new_mask
, cpus_allowed
);
3943 free_cpumask_var(new_mask
);
3944 out_free_cpus_allowed
:
3945 free_cpumask_var(cpus_allowed
);
3951 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
3952 struct cpumask
*new_mask
)
3954 if (len
< cpumask_size())
3955 cpumask_clear(new_mask
);
3956 else if (len
> cpumask_size())
3957 len
= cpumask_size();
3959 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
3963 * sys_sched_setaffinity - set the cpu affinity of a process
3964 * @pid: pid of the process
3965 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
3966 * @user_mask_ptr: user-space pointer to the new cpu mask
3968 * Return: 0 on success. An error code otherwise.
3970 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
3971 unsigned long __user
*, user_mask_ptr
)
3973 cpumask_var_t new_mask
;
3976 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
3979 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
3981 retval
= sched_setaffinity(pid
, new_mask
);
3982 free_cpumask_var(new_mask
);
3986 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
3988 struct task_struct
*p
;
3989 unsigned long flags
;
3995 p
= find_process_by_pid(pid
);
3999 retval
= security_task_getscheduler(p
);
4003 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4004 cpumask_and(mask
, &p
->cpus_allowed
, cpu_active_mask
);
4005 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4014 * sys_sched_getaffinity - get the cpu affinity of a process
4015 * @pid: pid of the process
4016 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4017 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4019 * Return: 0 on success. An error code otherwise.
4021 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4022 unsigned long __user
*, user_mask_ptr
)
4027 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4029 if (len
& (sizeof(unsigned long)-1))
4032 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4035 ret
= sched_getaffinity(pid
, mask
);
4037 size_t retlen
= min_t(size_t, len
, cpumask_size());
4039 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4044 free_cpumask_var(mask
);
4050 * sys_sched_yield - yield the current processor to other threads.
4052 * This function yields the current CPU to other tasks. If there are no
4053 * other threads running on this CPU then this function will return.
4057 SYSCALL_DEFINE0(sched_yield
)
4059 struct rq
*rq
= this_rq_lock();
4061 schedstat_inc(rq
, yld_count
);
4062 current
->sched_class
->yield_task(rq
);
4065 * Since we are going to call schedule() anyway, there's
4066 * no need to preempt or enable interrupts:
4068 __release(rq
->lock
);
4069 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4070 do_raw_spin_unlock(&rq
->lock
);
4071 sched_preempt_enable_no_resched();
4078 static void __cond_resched(void)
4080 __preempt_count_add(PREEMPT_ACTIVE
);
4082 __preempt_count_sub(PREEMPT_ACTIVE
);
4085 int __sched
_cond_resched(void)
4087 if (should_resched()) {
4093 EXPORT_SYMBOL(_cond_resched
);
4096 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4097 * call schedule, and on return reacquire the lock.
4099 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4100 * operations here to prevent schedule() from being called twice (once via
4101 * spin_unlock(), once by hand).
4103 int __cond_resched_lock(spinlock_t
*lock
)
4105 int resched
= should_resched();
4108 lockdep_assert_held(lock
);
4110 if (spin_needbreak(lock
) || resched
) {
4121 EXPORT_SYMBOL(__cond_resched_lock
);
4123 int __sched
__cond_resched_softirq(void)
4125 BUG_ON(!in_softirq());
4127 if (should_resched()) {
4135 EXPORT_SYMBOL(__cond_resched_softirq
);
4138 * yield - yield the current processor to other threads.
4140 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4142 * The scheduler is at all times free to pick the calling task as the most
4143 * eligible task to run, if removing the yield() call from your code breaks
4144 * it, its already broken.
4146 * Typical broken usage is:
4151 * where one assumes that yield() will let 'the other' process run that will
4152 * make event true. If the current task is a SCHED_FIFO task that will never
4153 * happen. Never use yield() as a progress guarantee!!
4155 * If you want to use yield() to wait for something, use wait_event().
4156 * If you want to use yield() to be 'nice' for others, use cond_resched().
4157 * If you still want to use yield(), do not!
4159 void __sched
yield(void)
4161 set_current_state(TASK_RUNNING
);
4164 EXPORT_SYMBOL(yield
);
4167 * yield_to - yield the current processor to another thread in
4168 * your thread group, or accelerate that thread toward the
4169 * processor it's on.
4171 * @preempt: whether task preemption is allowed or not
4173 * It's the caller's job to ensure that the target task struct
4174 * can't go away on us before we can do any checks.
4177 * true (>0) if we indeed boosted the target task.
4178 * false (0) if we failed to boost the target.
4179 * -ESRCH if there's no task to yield to.
4181 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
4183 struct task_struct
*curr
= current
;
4184 struct rq
*rq
, *p_rq
;
4185 unsigned long flags
;
4188 local_irq_save(flags
);
4194 * If we're the only runnable task on the rq and target rq also
4195 * has only one task, there's absolutely no point in yielding.
4197 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
4202 double_rq_lock(rq
, p_rq
);
4203 if (task_rq(p
) != p_rq
) {
4204 double_rq_unlock(rq
, p_rq
);
4208 if (!curr
->sched_class
->yield_to_task
)
4211 if (curr
->sched_class
!= p
->sched_class
)
4214 if (task_running(p_rq
, p
) || p
->state
)
4217 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4219 schedstat_inc(rq
, yld_count
);
4221 * Make p's CPU reschedule; pick_next_entity takes care of
4224 if (preempt
&& rq
!= p_rq
)
4225 resched_task(p_rq
->curr
);
4229 double_rq_unlock(rq
, p_rq
);
4231 local_irq_restore(flags
);
4238 EXPORT_SYMBOL_GPL(yield_to
);
4241 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4242 * that process accounting knows that this is a task in IO wait state.
4244 void __sched
io_schedule(void)
4246 struct rq
*rq
= raw_rq();
4248 delayacct_blkio_start();
4249 atomic_inc(&rq
->nr_iowait
);
4250 blk_flush_plug(current
);
4251 current
->in_iowait
= 1;
4253 current
->in_iowait
= 0;
4254 atomic_dec(&rq
->nr_iowait
);
4255 delayacct_blkio_end();
4257 EXPORT_SYMBOL(io_schedule
);
4259 long __sched
io_schedule_timeout(long timeout
)
4261 struct rq
*rq
= raw_rq();
4264 delayacct_blkio_start();
4265 atomic_inc(&rq
->nr_iowait
);
4266 blk_flush_plug(current
);
4267 current
->in_iowait
= 1;
4268 ret
= schedule_timeout(timeout
);
4269 current
->in_iowait
= 0;
4270 atomic_dec(&rq
->nr_iowait
);
4271 delayacct_blkio_end();
4276 * sys_sched_get_priority_max - return maximum RT priority.
4277 * @policy: scheduling class.
4279 * Return: On success, this syscall returns the maximum
4280 * rt_priority that can be used by a given scheduling class.
4281 * On failure, a negative error code is returned.
4283 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4290 ret
= MAX_USER_RT_PRIO
-1;
4292 case SCHED_DEADLINE
:
4303 * sys_sched_get_priority_min - return minimum RT priority.
4304 * @policy: scheduling class.
4306 * Return: On success, this syscall returns the minimum
4307 * rt_priority that can be used by a given scheduling class.
4308 * On failure, a negative error code is returned.
4310 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4319 case SCHED_DEADLINE
:
4329 * sys_sched_rr_get_interval - return the default timeslice of a process.
4330 * @pid: pid of the process.
4331 * @interval: userspace pointer to the timeslice value.
4333 * this syscall writes the default timeslice value of a given process
4334 * into the user-space timespec buffer. A value of '0' means infinity.
4336 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4339 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4340 struct timespec __user
*, interval
)
4342 struct task_struct
*p
;
4343 unsigned int time_slice
;
4344 unsigned long flags
;
4354 p
= find_process_by_pid(pid
);
4358 retval
= security_task_getscheduler(p
);
4362 rq
= task_rq_lock(p
, &flags
);
4364 if (p
->sched_class
->get_rr_interval
)
4365 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4366 task_rq_unlock(rq
, p
, &flags
);
4369 jiffies_to_timespec(time_slice
, &t
);
4370 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4378 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4380 void sched_show_task(struct task_struct
*p
)
4382 unsigned long free
= 0;
4386 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4387 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4388 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4389 #if BITS_PER_LONG == 32
4390 if (state
== TASK_RUNNING
)
4391 printk(KERN_CONT
" running ");
4393 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4395 if (state
== TASK_RUNNING
)
4396 printk(KERN_CONT
" running task ");
4398 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4400 #ifdef CONFIG_DEBUG_STACK_USAGE
4401 free
= stack_not_used(p
);
4404 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4406 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4407 task_pid_nr(p
), ppid
,
4408 (unsigned long)task_thread_info(p
)->flags
);
4410 print_worker_info(KERN_INFO
, p
);
4411 show_stack(p
, NULL
);
4414 void show_state_filter(unsigned long state_filter
)
4416 struct task_struct
*g
, *p
;
4418 #if BITS_PER_LONG == 32
4420 " task PC stack pid father\n");
4423 " task PC stack pid father\n");
4426 do_each_thread(g
, p
) {
4428 * reset the NMI-timeout, listing all files on a slow
4429 * console might take a lot of time:
4431 touch_nmi_watchdog();
4432 if (!state_filter
|| (p
->state
& state_filter
))
4434 } while_each_thread(g
, p
);
4436 touch_all_softlockup_watchdogs();
4438 #ifdef CONFIG_SCHED_DEBUG
4439 sysrq_sched_debug_show();
4443 * Only show locks if all tasks are dumped:
4446 debug_show_all_locks();
4449 void init_idle_bootup_task(struct task_struct
*idle
)
4451 idle
->sched_class
= &idle_sched_class
;
4455 * init_idle - set up an idle thread for a given CPU
4456 * @idle: task in question
4457 * @cpu: cpu the idle task belongs to
4459 * NOTE: this function does not set the idle thread's NEED_RESCHED
4460 * flag, to make booting more robust.
4462 void init_idle(struct task_struct
*idle
, int cpu
)
4464 struct rq
*rq
= cpu_rq(cpu
);
4465 unsigned long flags
;
4467 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4469 __sched_fork(0, idle
);
4470 idle
->state
= TASK_RUNNING
;
4471 idle
->se
.exec_start
= sched_clock();
4473 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4475 * We're having a chicken and egg problem, even though we are
4476 * holding rq->lock, the cpu isn't yet set to this cpu so the
4477 * lockdep check in task_group() will fail.
4479 * Similar case to sched_fork(). / Alternatively we could
4480 * use task_rq_lock() here and obtain the other rq->lock.
4485 __set_task_cpu(idle
, cpu
);
4488 rq
->curr
= rq
->idle
= idle
;
4490 #if defined(CONFIG_SMP)
4493 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4495 /* Set the preempt count _outside_ the spinlocks! */
4496 init_idle_preempt_count(idle
, cpu
);
4499 * The idle tasks have their own, simple scheduling class:
4501 idle
->sched_class
= &idle_sched_class
;
4502 ftrace_graph_init_idle_task(idle
, cpu
);
4503 vtime_init_idle(idle
, cpu
);
4504 #if defined(CONFIG_SMP)
4505 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4510 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4512 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4513 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4515 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4516 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4520 * This is how migration works:
4522 * 1) we invoke migration_cpu_stop() on the target CPU using
4524 * 2) stopper starts to run (implicitly forcing the migrated thread
4526 * 3) it checks whether the migrated task is still in the wrong runqueue.
4527 * 4) if it's in the wrong runqueue then the migration thread removes
4528 * it and puts it into the right queue.
4529 * 5) stopper completes and stop_one_cpu() returns and the migration
4534 * Change a given task's CPU affinity. Migrate the thread to a
4535 * proper CPU and schedule it away if the CPU it's executing on
4536 * is removed from the allowed bitmask.
4538 * NOTE: the caller must have a valid reference to the task, the
4539 * task must not exit() & deallocate itself prematurely. The
4540 * call is not atomic; no spinlocks may be held.
4542 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4544 unsigned long flags
;
4546 unsigned int dest_cpu
;
4549 rq
= task_rq_lock(p
, &flags
);
4551 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4554 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4559 do_set_cpus_allowed(p
, new_mask
);
4561 /* Can the task run on the task's current CPU? If so, we're done */
4562 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4565 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4567 struct migration_arg arg
= { p
, dest_cpu
};
4568 /* Need help from migration thread: drop lock and wait. */
4569 task_rq_unlock(rq
, p
, &flags
);
4570 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4571 tlb_migrate_finish(p
->mm
);
4575 task_rq_unlock(rq
, p
, &flags
);
4579 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4582 * Move (not current) task off this cpu, onto dest cpu. We're doing
4583 * this because either it can't run here any more (set_cpus_allowed()
4584 * away from this CPU, or CPU going down), or because we're
4585 * attempting to rebalance this task on exec (sched_exec).
4587 * So we race with normal scheduler movements, but that's OK, as long
4588 * as the task is no longer on this CPU.
4590 * Returns non-zero if task was successfully migrated.
4592 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4594 struct rq
*rq_dest
, *rq_src
;
4597 if (unlikely(!cpu_active(dest_cpu
)))
4600 rq_src
= cpu_rq(src_cpu
);
4601 rq_dest
= cpu_rq(dest_cpu
);
4603 raw_spin_lock(&p
->pi_lock
);
4604 double_rq_lock(rq_src
, rq_dest
);
4605 /* Already moved. */
4606 if (task_cpu(p
) != src_cpu
)
4608 /* Affinity changed (again). */
4609 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4613 * If we're not on a rq, the next wake-up will ensure we're
4617 dequeue_task(rq_src
, p
, 0);
4618 set_task_cpu(p
, dest_cpu
);
4619 enqueue_task(rq_dest
, p
, 0);
4620 check_preempt_curr(rq_dest
, p
, 0);
4625 double_rq_unlock(rq_src
, rq_dest
);
4626 raw_spin_unlock(&p
->pi_lock
);
4630 #ifdef CONFIG_NUMA_BALANCING
4631 /* Migrate current task p to target_cpu */
4632 int migrate_task_to(struct task_struct
*p
, int target_cpu
)
4634 struct migration_arg arg
= { p
, target_cpu
};
4635 int curr_cpu
= task_cpu(p
);
4637 if (curr_cpu
== target_cpu
)
4640 if (!cpumask_test_cpu(target_cpu
, tsk_cpus_allowed(p
)))
4643 /* TODO: This is not properly updating schedstats */
4645 trace_sched_move_numa(p
, curr_cpu
, target_cpu
);
4646 return stop_one_cpu(curr_cpu
, migration_cpu_stop
, &arg
);
4650 * Requeue a task on a given node and accurately track the number of NUMA
4651 * tasks on the runqueues
4653 void sched_setnuma(struct task_struct
*p
, int nid
)
4656 unsigned long flags
;
4657 bool on_rq
, running
;
4659 rq
= task_rq_lock(p
, &flags
);
4661 running
= task_current(rq
, p
);
4664 dequeue_task(rq
, p
, 0);
4666 p
->sched_class
->put_prev_task(rq
, p
);
4668 p
->numa_preferred_nid
= nid
;
4671 p
->sched_class
->set_curr_task(rq
);
4673 enqueue_task(rq
, p
, 0);
4674 task_rq_unlock(rq
, p
, &flags
);
4679 * migration_cpu_stop - this will be executed by a highprio stopper thread
4680 * and performs thread migration by bumping thread off CPU then
4681 * 'pushing' onto another runqueue.
4683 static int migration_cpu_stop(void *data
)
4685 struct migration_arg
*arg
= data
;
4688 * The original target cpu might have gone down and we might
4689 * be on another cpu but it doesn't matter.
4691 local_irq_disable();
4692 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4697 #ifdef CONFIG_HOTPLUG_CPU
4700 * Ensures that the idle task is using init_mm right before its cpu goes
4703 void idle_task_exit(void)
4705 struct mm_struct
*mm
= current
->active_mm
;
4707 BUG_ON(cpu_online(smp_processor_id()));
4709 if (mm
!= &init_mm
) {
4710 switch_mm(mm
, &init_mm
, current
);
4711 finish_arch_post_lock_switch();
4717 * Since this CPU is going 'away' for a while, fold any nr_active delta
4718 * we might have. Assumes we're called after migrate_tasks() so that the
4719 * nr_active count is stable.
4721 * Also see the comment "Global load-average calculations".
4723 static void calc_load_migrate(struct rq
*rq
)
4725 long delta
= calc_load_fold_active(rq
);
4727 atomic_long_add(delta
, &calc_load_tasks
);
4730 static void put_prev_task_fake(struct rq
*rq
, struct task_struct
*prev
)
4734 static const struct sched_class fake_sched_class
= {
4735 .put_prev_task
= put_prev_task_fake
,
4738 static struct task_struct fake_task
= {
4740 * Avoid pull_{rt,dl}_task()
4742 .prio
= MAX_PRIO
+ 1,
4743 .sched_class
= &fake_sched_class
,
4747 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4748 * try_to_wake_up()->select_task_rq().
4750 * Called with rq->lock held even though we'er in stop_machine() and
4751 * there's no concurrency possible, we hold the required locks anyway
4752 * because of lock validation efforts.
4754 static void migrate_tasks(unsigned int dead_cpu
)
4756 struct rq
*rq
= cpu_rq(dead_cpu
);
4757 struct task_struct
*next
, *stop
= rq
->stop
;
4761 * Fudge the rq selection such that the below task selection loop
4762 * doesn't get stuck on the currently eligible stop task.
4764 * We're currently inside stop_machine() and the rq is either stuck
4765 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4766 * either way we should never end up calling schedule() until we're
4772 * put_prev_task() and pick_next_task() sched
4773 * class method both need to have an up-to-date
4774 * value of rq->clock[_task]
4776 update_rq_clock(rq
);
4780 * There's this thread running, bail when that's the only
4783 if (rq
->nr_running
== 1)
4786 next
= pick_next_task(rq
, &fake_task
);
4788 next
->sched_class
->put_prev_task(rq
, next
);
4790 /* Find suitable destination for @next, with force if needed. */
4791 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
4792 raw_spin_unlock(&rq
->lock
);
4794 __migrate_task(next
, dead_cpu
, dest_cpu
);
4796 raw_spin_lock(&rq
->lock
);
4802 #endif /* CONFIG_HOTPLUG_CPU */
4804 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4806 static struct ctl_table sd_ctl_dir
[] = {
4808 .procname
= "sched_domain",
4814 static struct ctl_table sd_ctl_root
[] = {
4816 .procname
= "kernel",
4818 .child
= sd_ctl_dir
,
4823 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
4825 struct ctl_table
*entry
=
4826 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
4831 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
4833 struct ctl_table
*entry
;
4836 * In the intermediate directories, both the child directory and
4837 * procname are dynamically allocated and could fail but the mode
4838 * will always be set. In the lowest directory the names are
4839 * static strings and all have proc handlers.
4841 for (entry
= *tablep
; entry
->mode
; entry
++) {
4843 sd_free_ctl_entry(&entry
->child
);
4844 if (entry
->proc_handler
== NULL
)
4845 kfree(entry
->procname
);
4852 static int min_load_idx
= 0;
4853 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
4856 set_table_entry(struct ctl_table
*entry
,
4857 const char *procname
, void *data
, int maxlen
,
4858 umode_t mode
, proc_handler
*proc_handler
,
4861 entry
->procname
= procname
;
4863 entry
->maxlen
= maxlen
;
4865 entry
->proc_handler
= proc_handler
;
4868 entry
->extra1
= &min_load_idx
;
4869 entry
->extra2
= &max_load_idx
;
4873 static struct ctl_table
*
4874 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
4876 struct ctl_table
*table
= sd_alloc_ctl_entry(14);
4881 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
4882 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4883 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
4884 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4885 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
4886 sizeof(int), 0644, proc_dointvec_minmax
, true);
4887 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
4888 sizeof(int), 0644, proc_dointvec_minmax
, true);
4889 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
4890 sizeof(int), 0644, proc_dointvec_minmax
, true);
4891 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
4892 sizeof(int), 0644, proc_dointvec_minmax
, true);
4893 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
4894 sizeof(int), 0644, proc_dointvec_minmax
, true);
4895 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
4896 sizeof(int), 0644, proc_dointvec_minmax
, false);
4897 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
4898 sizeof(int), 0644, proc_dointvec_minmax
, false);
4899 set_table_entry(&table
[9], "cache_nice_tries",
4900 &sd
->cache_nice_tries
,
4901 sizeof(int), 0644, proc_dointvec_minmax
, false);
4902 set_table_entry(&table
[10], "flags", &sd
->flags
,
4903 sizeof(int), 0644, proc_dointvec_minmax
, false);
4904 set_table_entry(&table
[11], "max_newidle_lb_cost",
4905 &sd
->max_newidle_lb_cost
,
4906 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4907 set_table_entry(&table
[12], "name", sd
->name
,
4908 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
4909 /* &table[13] is terminator */
4914 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
4916 struct ctl_table
*entry
, *table
;
4917 struct sched_domain
*sd
;
4918 int domain_num
= 0, i
;
4921 for_each_domain(cpu
, sd
)
4923 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
4928 for_each_domain(cpu
, sd
) {
4929 snprintf(buf
, 32, "domain%d", i
);
4930 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4932 entry
->child
= sd_alloc_ctl_domain_table(sd
);
4939 static struct ctl_table_header
*sd_sysctl_header
;
4940 static void register_sched_domain_sysctl(void)
4942 int i
, cpu_num
= num_possible_cpus();
4943 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
4946 WARN_ON(sd_ctl_dir
[0].child
);
4947 sd_ctl_dir
[0].child
= entry
;
4952 for_each_possible_cpu(i
) {
4953 snprintf(buf
, 32, "cpu%d", i
);
4954 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
4956 entry
->child
= sd_alloc_ctl_cpu_table(i
);
4960 WARN_ON(sd_sysctl_header
);
4961 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
4964 /* may be called multiple times per register */
4965 static void unregister_sched_domain_sysctl(void)
4967 if (sd_sysctl_header
)
4968 unregister_sysctl_table(sd_sysctl_header
);
4969 sd_sysctl_header
= NULL
;
4970 if (sd_ctl_dir
[0].child
)
4971 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
4974 static void register_sched_domain_sysctl(void)
4977 static void unregister_sched_domain_sysctl(void)
4982 static void set_rq_online(struct rq
*rq
)
4985 const struct sched_class
*class;
4987 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
4990 for_each_class(class) {
4991 if (class->rq_online
)
4992 class->rq_online(rq
);
4997 static void set_rq_offline(struct rq
*rq
)
5000 const struct sched_class
*class;
5002 for_each_class(class) {
5003 if (class->rq_offline
)
5004 class->rq_offline(rq
);
5007 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5013 * migration_call - callback that gets triggered when a CPU is added.
5014 * Here we can start up the necessary migration thread for the new CPU.
5017 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5019 int cpu
= (long)hcpu
;
5020 unsigned long flags
;
5021 struct rq
*rq
= cpu_rq(cpu
);
5023 switch (action
& ~CPU_TASKS_FROZEN
) {
5025 case CPU_UP_PREPARE
:
5026 rq
->calc_load_update
= calc_load_update
;
5030 /* Update our root-domain */
5031 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5033 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5037 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5040 #ifdef CONFIG_HOTPLUG_CPU
5042 sched_ttwu_pending();
5043 /* Update our root-domain */
5044 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5046 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5050 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5051 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5055 calc_load_migrate(rq
);
5060 update_max_interval();
5066 * Register at high priority so that task migration (migrate_all_tasks)
5067 * happens before everything else. This has to be lower priority than
5068 * the notifier in the perf_event subsystem, though.
5070 static struct notifier_block migration_notifier
= {
5071 .notifier_call
= migration_call
,
5072 .priority
= CPU_PRI_MIGRATION
,
5075 static int sched_cpu_active(struct notifier_block
*nfb
,
5076 unsigned long action
, void *hcpu
)
5078 switch (action
& ~CPU_TASKS_FROZEN
) {
5080 case CPU_DOWN_FAILED
:
5081 set_cpu_active((long)hcpu
, true);
5088 static int sched_cpu_inactive(struct notifier_block
*nfb
,
5089 unsigned long action
, void *hcpu
)
5091 unsigned long flags
;
5092 long cpu
= (long)hcpu
;
5094 switch (action
& ~CPU_TASKS_FROZEN
) {
5095 case CPU_DOWN_PREPARE
:
5096 set_cpu_active(cpu
, false);
5098 /* explicitly allow suspend */
5099 if (!(action
& CPU_TASKS_FROZEN
)) {
5100 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
5104 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
5105 cpus
= dl_bw_cpus(cpu
);
5106 overflow
= __dl_overflow(dl_b
, cpus
, 0, 0);
5107 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
5110 return notifier_from_errno(-EBUSY
);
5118 static int __init
migration_init(void)
5120 void *cpu
= (void *)(long)smp_processor_id();
5123 /* Initialize migration for the boot CPU */
5124 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5125 BUG_ON(err
== NOTIFY_BAD
);
5126 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5127 register_cpu_notifier(&migration_notifier
);
5129 /* Register cpu active notifiers */
5130 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5131 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5135 early_initcall(migration_init
);
5140 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5142 #ifdef CONFIG_SCHED_DEBUG
5144 static __read_mostly
int sched_debug_enabled
;
5146 static int __init
sched_debug_setup(char *str
)
5148 sched_debug_enabled
= 1;
5152 early_param("sched_debug", sched_debug_setup
);
5154 static inline bool sched_debug(void)
5156 return sched_debug_enabled
;
5159 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5160 struct cpumask
*groupmask
)
5162 struct sched_group
*group
= sd
->groups
;
5165 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5166 cpumask_clear(groupmask
);
5168 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5170 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5171 printk("does not load-balance\n");
5173 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5178 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5180 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5181 printk(KERN_ERR
"ERROR: domain->span does not contain "
5184 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5185 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5189 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5193 printk(KERN_ERR
"ERROR: group is NULL\n");
5198 * Even though we initialize ->power to something semi-sane,
5199 * we leave power_orig unset. This allows us to detect if
5200 * domain iteration is still funny without causing /0 traps.
5202 if (!group
->sgp
->power_orig
) {
5203 printk(KERN_CONT
"\n");
5204 printk(KERN_ERR
"ERROR: domain->cpu_power not "
5209 if (!cpumask_weight(sched_group_cpus(group
))) {
5210 printk(KERN_CONT
"\n");
5211 printk(KERN_ERR
"ERROR: empty group\n");
5215 if (!(sd
->flags
& SD_OVERLAP
) &&
5216 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5217 printk(KERN_CONT
"\n");
5218 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5222 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5224 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
5226 printk(KERN_CONT
" %s", str
);
5227 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
5228 printk(KERN_CONT
" (cpu_power = %d)",
5232 group
= group
->next
;
5233 } while (group
!= sd
->groups
);
5234 printk(KERN_CONT
"\n");
5236 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5237 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5240 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5241 printk(KERN_ERR
"ERROR: parent span is not a superset "
5242 "of domain->span\n");
5246 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5250 if (!sched_debug_enabled
)
5254 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5258 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5261 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5269 #else /* !CONFIG_SCHED_DEBUG */
5270 # define sched_domain_debug(sd, cpu) do { } while (0)
5271 static inline bool sched_debug(void)
5275 #endif /* CONFIG_SCHED_DEBUG */
5277 static int sd_degenerate(struct sched_domain
*sd
)
5279 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5282 /* Following flags need at least 2 groups */
5283 if (sd
->flags
& (SD_LOAD_BALANCE
|
5284 SD_BALANCE_NEWIDLE
|
5288 SD_SHARE_PKG_RESOURCES
)) {
5289 if (sd
->groups
!= sd
->groups
->next
)
5293 /* Following flags don't use groups */
5294 if (sd
->flags
& (SD_WAKE_AFFINE
))
5301 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5303 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5305 if (sd_degenerate(parent
))
5308 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5311 /* Flags needing groups don't count if only 1 group in parent */
5312 if (parent
->groups
== parent
->groups
->next
) {
5313 pflags
&= ~(SD_LOAD_BALANCE
|
5314 SD_BALANCE_NEWIDLE
|
5318 SD_SHARE_PKG_RESOURCES
|
5320 if (nr_node_ids
== 1)
5321 pflags
&= ~SD_SERIALIZE
;
5323 if (~cflags
& pflags
)
5329 static void free_rootdomain(struct rcu_head
*rcu
)
5331 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5333 cpupri_cleanup(&rd
->cpupri
);
5334 cpudl_cleanup(&rd
->cpudl
);
5335 free_cpumask_var(rd
->dlo_mask
);
5336 free_cpumask_var(rd
->rto_mask
);
5337 free_cpumask_var(rd
->online
);
5338 free_cpumask_var(rd
->span
);
5342 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5344 struct root_domain
*old_rd
= NULL
;
5345 unsigned long flags
;
5347 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5352 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5355 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5358 * If we dont want to free the old_rd yet then
5359 * set old_rd to NULL to skip the freeing later
5362 if (!atomic_dec_and_test(&old_rd
->refcount
))
5366 atomic_inc(&rd
->refcount
);
5369 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5370 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5373 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5376 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5379 static int init_rootdomain(struct root_domain
*rd
)
5381 memset(rd
, 0, sizeof(*rd
));
5383 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5385 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5387 if (!alloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
5389 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5392 init_dl_bw(&rd
->dl_bw
);
5393 if (cpudl_init(&rd
->cpudl
) != 0)
5396 if (cpupri_init(&rd
->cpupri
) != 0)
5401 free_cpumask_var(rd
->rto_mask
);
5403 free_cpumask_var(rd
->dlo_mask
);
5405 free_cpumask_var(rd
->online
);
5407 free_cpumask_var(rd
->span
);
5413 * By default the system creates a single root-domain with all cpus as
5414 * members (mimicking the global state we have today).
5416 struct root_domain def_root_domain
;
5418 static void init_defrootdomain(void)
5420 init_rootdomain(&def_root_domain
);
5422 atomic_set(&def_root_domain
.refcount
, 1);
5425 static struct root_domain
*alloc_rootdomain(void)
5427 struct root_domain
*rd
;
5429 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5433 if (init_rootdomain(rd
) != 0) {
5441 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
5443 struct sched_group
*tmp
, *first
;
5452 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
5457 } while (sg
!= first
);
5460 static void free_sched_domain(struct rcu_head
*rcu
)
5462 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5465 * If its an overlapping domain it has private groups, iterate and
5468 if (sd
->flags
& SD_OVERLAP
) {
5469 free_sched_groups(sd
->groups
, 1);
5470 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5471 kfree(sd
->groups
->sgp
);
5477 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5479 call_rcu(&sd
->rcu
, free_sched_domain
);
5482 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5484 for (; sd
; sd
= sd
->parent
)
5485 destroy_sched_domain(sd
, cpu
);
5489 * Keep a special pointer to the highest sched_domain that has
5490 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5491 * allows us to avoid some pointer chasing select_idle_sibling().
5493 * Also keep a unique ID per domain (we use the first cpu number in
5494 * the cpumask of the domain), this allows us to quickly tell if
5495 * two cpus are in the same cache domain, see cpus_share_cache().
5497 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5498 DEFINE_PER_CPU(int, sd_llc_size
);
5499 DEFINE_PER_CPU(int, sd_llc_id
);
5500 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
5501 DEFINE_PER_CPU(struct sched_domain
*, sd_busy
);
5502 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
5504 static void update_top_cache_domain(int cpu
)
5506 struct sched_domain
*sd
;
5507 struct sched_domain
*busy_sd
= NULL
;
5511 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5513 id
= cpumask_first(sched_domain_span(sd
));
5514 size
= cpumask_weight(sched_domain_span(sd
));
5515 busy_sd
= sd
->parent
; /* sd_busy */
5517 rcu_assign_pointer(per_cpu(sd_busy
, cpu
), busy_sd
);
5519 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5520 per_cpu(sd_llc_size
, cpu
) = size
;
5521 per_cpu(sd_llc_id
, cpu
) = id
;
5523 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
5524 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
5526 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
5527 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
5531 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5532 * hold the hotplug lock.
5535 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5537 struct rq
*rq
= cpu_rq(cpu
);
5538 struct sched_domain
*tmp
;
5540 /* Remove the sched domains which do not contribute to scheduling. */
5541 for (tmp
= sd
; tmp
; ) {
5542 struct sched_domain
*parent
= tmp
->parent
;
5546 if (sd_parent_degenerate(tmp
, parent
)) {
5547 tmp
->parent
= parent
->parent
;
5549 parent
->parent
->child
= tmp
;
5551 * Transfer SD_PREFER_SIBLING down in case of a
5552 * degenerate parent; the spans match for this
5553 * so the property transfers.
5555 if (parent
->flags
& SD_PREFER_SIBLING
)
5556 tmp
->flags
|= SD_PREFER_SIBLING
;
5557 destroy_sched_domain(parent
, cpu
);
5562 if (sd
&& sd_degenerate(sd
)) {
5565 destroy_sched_domain(tmp
, cpu
);
5570 sched_domain_debug(sd
, cpu
);
5572 rq_attach_root(rq
, rd
);
5574 rcu_assign_pointer(rq
->sd
, sd
);
5575 destroy_sched_domains(tmp
, cpu
);
5577 update_top_cache_domain(cpu
);
5580 /* cpus with isolated domains */
5581 static cpumask_var_t cpu_isolated_map
;
5583 /* Setup the mask of cpus configured for isolated domains */
5584 static int __init
isolated_cpu_setup(char *str
)
5586 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5587 cpulist_parse(str
, cpu_isolated_map
);
5591 __setup("isolcpus=", isolated_cpu_setup
);
5593 static const struct cpumask
*cpu_cpu_mask(int cpu
)
5595 return cpumask_of_node(cpu_to_node(cpu
));
5599 struct sched_domain
**__percpu sd
;
5600 struct sched_group
**__percpu sg
;
5601 struct sched_group_power
**__percpu sgp
;
5605 struct sched_domain
** __percpu sd
;
5606 struct root_domain
*rd
;
5616 struct sched_domain_topology_level
;
5618 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
5619 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
5621 #define SDTL_OVERLAP 0x01
5623 struct sched_domain_topology_level
{
5624 sched_domain_init_f init
;
5625 sched_domain_mask_f mask
;
5628 struct sd_data data
;
5632 * Build an iteration mask that can exclude certain CPUs from the upwards
5635 * Asymmetric node setups can result in situations where the domain tree is of
5636 * unequal depth, make sure to skip domains that already cover the entire
5639 * In that case build_sched_domains() will have terminated the iteration early
5640 * and our sibling sd spans will be empty. Domains should always include the
5641 * cpu they're built on, so check that.
5644 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5646 const struct cpumask
*span
= sched_domain_span(sd
);
5647 struct sd_data
*sdd
= sd
->private;
5648 struct sched_domain
*sibling
;
5651 for_each_cpu(i
, span
) {
5652 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5653 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5656 cpumask_set_cpu(i
, sched_group_mask(sg
));
5661 * Return the canonical balance cpu for this group, this is the first cpu
5662 * of this group that's also in the iteration mask.
5664 int group_balance_cpu(struct sched_group
*sg
)
5666 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5670 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5672 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5673 const struct cpumask
*span
= sched_domain_span(sd
);
5674 struct cpumask
*covered
= sched_domains_tmpmask
;
5675 struct sd_data
*sdd
= sd
->private;
5676 struct sched_domain
*child
;
5679 cpumask_clear(covered
);
5681 for_each_cpu(i
, span
) {
5682 struct cpumask
*sg_span
;
5684 if (cpumask_test_cpu(i
, covered
))
5687 child
= *per_cpu_ptr(sdd
->sd
, i
);
5689 /* See the comment near build_group_mask(). */
5690 if (!cpumask_test_cpu(i
, sched_domain_span(child
)))
5693 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5694 GFP_KERNEL
, cpu_to_node(cpu
));
5699 sg_span
= sched_group_cpus(sg
);
5701 child
= child
->child
;
5702 cpumask_copy(sg_span
, sched_domain_span(child
));
5704 cpumask_set_cpu(i
, sg_span
);
5706 cpumask_or(covered
, covered
, sg_span
);
5708 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, i
);
5709 if (atomic_inc_return(&sg
->sgp
->ref
) == 1)
5710 build_group_mask(sd
, sg
);
5713 * Initialize sgp->power such that even if we mess up the
5714 * domains and no possible iteration will get us here, we won't
5717 sg
->sgp
->power
= SCHED_POWER_SCALE
* cpumask_weight(sg_span
);
5718 sg
->sgp
->power_orig
= sg
->sgp
->power
;
5721 * Make sure the first group of this domain contains the
5722 * canonical balance cpu. Otherwise the sched_domain iteration
5723 * breaks. See update_sg_lb_stats().
5725 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5726 group_balance_cpu(sg
) == cpu
)
5736 sd
->groups
= groups
;
5741 free_sched_groups(first
, 0);
5746 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5748 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5749 struct sched_domain
*child
= sd
->child
;
5752 cpu
= cpumask_first(sched_domain_span(child
));
5755 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5756 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
5757 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
5764 * build_sched_groups will build a circular linked list of the groups
5765 * covered by the given span, and will set each group's ->cpumask correctly,
5766 * and ->cpu_power to 0.
5768 * Assumes the sched_domain tree is fully constructed
5771 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5773 struct sched_group
*first
= NULL
, *last
= NULL
;
5774 struct sd_data
*sdd
= sd
->private;
5775 const struct cpumask
*span
= sched_domain_span(sd
);
5776 struct cpumask
*covered
;
5779 get_group(cpu
, sdd
, &sd
->groups
);
5780 atomic_inc(&sd
->groups
->ref
);
5782 if (cpu
!= cpumask_first(span
))
5785 lockdep_assert_held(&sched_domains_mutex
);
5786 covered
= sched_domains_tmpmask
;
5788 cpumask_clear(covered
);
5790 for_each_cpu(i
, span
) {
5791 struct sched_group
*sg
;
5794 if (cpumask_test_cpu(i
, covered
))
5797 group
= get_group(i
, sdd
, &sg
);
5798 cpumask_clear(sched_group_cpus(sg
));
5800 cpumask_setall(sched_group_mask(sg
));
5802 for_each_cpu(j
, span
) {
5803 if (get_group(j
, sdd
, NULL
) != group
)
5806 cpumask_set_cpu(j
, covered
);
5807 cpumask_set_cpu(j
, sched_group_cpus(sg
));
5822 * Initialize sched groups cpu_power.
5824 * cpu_power indicates the capacity of sched group, which is used while
5825 * distributing the load between different sched groups in a sched domain.
5826 * Typically cpu_power for all the groups in a sched domain will be same unless
5827 * there are asymmetries in the topology. If there are asymmetries, group
5828 * having more cpu_power will pickup more load compared to the group having
5831 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
5833 struct sched_group
*sg
= sd
->groups
;
5838 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
5840 } while (sg
!= sd
->groups
);
5842 if (cpu
!= group_balance_cpu(sg
))
5845 update_group_power(sd
, cpu
);
5846 atomic_set(&sg
->sgp
->nr_busy_cpus
, sg
->group_weight
);
5849 int __weak
arch_sd_sibling_asym_packing(void)
5851 return 0*SD_ASYM_PACKING
;
5855 * Initializers for schedule domains
5856 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5859 #ifdef CONFIG_SCHED_DEBUG
5860 # define SD_INIT_NAME(sd, type) sd->name = #type
5862 # define SD_INIT_NAME(sd, type) do { } while (0)
5865 #define SD_INIT_FUNC(type) \
5866 static noinline struct sched_domain * \
5867 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
5869 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
5870 *sd = SD_##type##_INIT; \
5871 SD_INIT_NAME(sd, type); \
5872 sd->private = &tl->data; \
5877 #ifdef CONFIG_SCHED_SMT
5878 SD_INIT_FUNC(SIBLING
)
5880 #ifdef CONFIG_SCHED_MC
5883 #ifdef CONFIG_SCHED_BOOK
5887 static int default_relax_domain_level
= -1;
5888 int sched_domain_level_max
;
5890 static int __init
setup_relax_domain_level(char *str
)
5892 if (kstrtoint(str
, 0, &default_relax_domain_level
))
5893 pr_warn("Unable to set relax_domain_level\n");
5897 __setup("relax_domain_level=", setup_relax_domain_level
);
5899 static void set_domain_attribute(struct sched_domain
*sd
,
5900 struct sched_domain_attr
*attr
)
5904 if (!attr
|| attr
->relax_domain_level
< 0) {
5905 if (default_relax_domain_level
< 0)
5908 request
= default_relax_domain_level
;
5910 request
= attr
->relax_domain_level
;
5911 if (request
< sd
->level
) {
5912 /* turn off idle balance on this domain */
5913 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5915 /* turn on idle balance on this domain */
5916 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5920 static void __sdt_free(const struct cpumask
*cpu_map
);
5921 static int __sdt_alloc(const struct cpumask
*cpu_map
);
5923 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
5924 const struct cpumask
*cpu_map
)
5928 if (!atomic_read(&d
->rd
->refcount
))
5929 free_rootdomain(&d
->rd
->rcu
); /* fall through */
5931 free_percpu(d
->sd
); /* fall through */
5933 __sdt_free(cpu_map
); /* fall through */
5939 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
5940 const struct cpumask
*cpu_map
)
5942 memset(d
, 0, sizeof(*d
));
5944 if (__sdt_alloc(cpu_map
))
5945 return sa_sd_storage
;
5946 d
->sd
= alloc_percpu(struct sched_domain
*);
5948 return sa_sd_storage
;
5949 d
->rd
= alloc_rootdomain();
5952 return sa_rootdomain
;
5956 * NULL the sd_data elements we've used to build the sched_domain and
5957 * sched_group structure so that the subsequent __free_domain_allocs()
5958 * will not free the data we're using.
5960 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
5962 struct sd_data
*sdd
= sd
->private;
5964 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
5965 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
5967 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
5968 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
5970 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
5971 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
5974 #ifdef CONFIG_SCHED_SMT
5975 static const struct cpumask
*cpu_smt_mask(int cpu
)
5977 return topology_thread_cpumask(cpu
);
5982 * Topology list, bottom-up.
5984 static struct sched_domain_topology_level default_topology
[] = {
5985 #ifdef CONFIG_SCHED_SMT
5986 { sd_init_SIBLING
, cpu_smt_mask
, },
5988 #ifdef CONFIG_SCHED_MC
5989 { sd_init_MC
, cpu_coregroup_mask
, },
5991 #ifdef CONFIG_SCHED_BOOK
5992 { sd_init_BOOK
, cpu_book_mask
, },
5994 { sd_init_CPU
, cpu_cpu_mask
, },
5998 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6000 #define for_each_sd_topology(tl) \
6001 for (tl = sched_domain_topology; tl->init; tl++)
6005 static int sched_domains_numa_levels
;
6006 static int *sched_domains_numa_distance
;
6007 static struct cpumask
***sched_domains_numa_masks
;
6008 static int sched_domains_curr_level
;
6010 static inline int sd_local_flags(int level
)
6012 if (sched_domains_numa_distance
[level
] > RECLAIM_DISTANCE
)
6015 return SD_BALANCE_EXEC
| SD_BALANCE_FORK
| SD_WAKE_AFFINE
;
6018 static struct sched_domain
*
6019 sd_numa_init(struct sched_domain_topology_level
*tl
, int cpu
)
6021 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
6022 int level
= tl
->numa_level
;
6023 int sd_weight
= cpumask_weight(
6024 sched_domains_numa_masks
[level
][cpu_to_node(cpu
)]);
6026 *sd
= (struct sched_domain
){
6027 .min_interval
= sd_weight
,
6028 .max_interval
= 2*sd_weight
,
6030 .imbalance_pct
= 125,
6031 .cache_nice_tries
= 2,
6038 .flags
= 1*SD_LOAD_BALANCE
6039 | 1*SD_BALANCE_NEWIDLE
6044 | 0*SD_SHARE_CPUPOWER
6045 | 0*SD_SHARE_PKG_RESOURCES
6047 | 0*SD_PREFER_SIBLING
6049 | sd_local_flags(level
)
6051 .last_balance
= jiffies
,
6052 .balance_interval
= sd_weight
,
6053 .max_newidle_lb_cost
= 0,
6054 .next_decay_max_lb_cost
= jiffies
,
6056 SD_INIT_NAME(sd
, NUMA
);
6057 sd
->private = &tl
->data
;
6060 * Ugly hack to pass state to sd_numa_mask()...
6062 sched_domains_curr_level
= tl
->numa_level
;
6067 static const struct cpumask
*sd_numa_mask(int cpu
)
6069 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6072 static void sched_numa_warn(const char *str
)
6074 static int done
= false;
6082 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6084 for (i
= 0; i
< nr_node_ids
; i
++) {
6085 printk(KERN_WARNING
" ");
6086 for (j
= 0; j
< nr_node_ids
; j
++)
6087 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6088 printk(KERN_CONT
"\n");
6090 printk(KERN_WARNING
"\n");
6093 static bool find_numa_distance(int distance
)
6097 if (distance
== node_distance(0, 0))
6100 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6101 if (sched_domains_numa_distance
[i
] == distance
)
6108 static void sched_init_numa(void)
6110 int next_distance
, curr_distance
= node_distance(0, 0);
6111 struct sched_domain_topology_level
*tl
;
6115 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6116 if (!sched_domains_numa_distance
)
6120 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6121 * unique distances in the node_distance() table.
6123 * Assumes node_distance(0,j) includes all distances in
6124 * node_distance(i,j) in order to avoid cubic time.
6126 next_distance
= curr_distance
;
6127 for (i
= 0; i
< nr_node_ids
; i
++) {
6128 for (j
= 0; j
< nr_node_ids
; j
++) {
6129 for (k
= 0; k
< nr_node_ids
; k
++) {
6130 int distance
= node_distance(i
, k
);
6132 if (distance
> curr_distance
&&
6133 (distance
< next_distance
||
6134 next_distance
== curr_distance
))
6135 next_distance
= distance
;
6138 * While not a strong assumption it would be nice to know
6139 * about cases where if node A is connected to B, B is not
6140 * equally connected to A.
6142 if (sched_debug() && node_distance(k
, i
) != distance
)
6143 sched_numa_warn("Node-distance not symmetric");
6145 if (sched_debug() && i
&& !find_numa_distance(distance
))
6146 sched_numa_warn("Node-0 not representative");
6148 if (next_distance
!= curr_distance
) {
6149 sched_domains_numa_distance
[level
++] = next_distance
;
6150 sched_domains_numa_levels
= level
;
6151 curr_distance
= next_distance
;
6156 * In case of sched_debug() we verify the above assumption.
6162 * 'level' contains the number of unique distances, excluding the
6163 * identity distance node_distance(i,i).
6165 * The sched_domains_numa_distance[] array includes the actual distance
6170 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6171 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6172 * the array will contain less then 'level' members. This could be
6173 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6174 * in other functions.
6176 * We reset it to 'level' at the end of this function.
6178 sched_domains_numa_levels
= 0;
6180 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6181 if (!sched_domains_numa_masks
)
6185 * Now for each level, construct a mask per node which contains all
6186 * cpus of nodes that are that many hops away from us.
6188 for (i
= 0; i
< level
; i
++) {
6189 sched_domains_numa_masks
[i
] =
6190 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6191 if (!sched_domains_numa_masks
[i
])
6194 for (j
= 0; j
< nr_node_ids
; j
++) {
6195 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6199 sched_domains_numa_masks
[i
][j
] = mask
;
6201 for (k
= 0; k
< nr_node_ids
; k
++) {
6202 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6205 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6210 tl
= kzalloc((ARRAY_SIZE(default_topology
) + level
) *
6211 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6216 * Copy the default topology bits..
6218 for (i
= 0; default_topology
[i
].init
; i
++)
6219 tl
[i
] = default_topology
[i
];
6222 * .. and append 'j' levels of NUMA goodness.
6224 for (j
= 0; j
< level
; i
++, j
++) {
6225 tl
[i
] = (struct sched_domain_topology_level
){
6226 .init
= sd_numa_init
,
6227 .mask
= sd_numa_mask
,
6228 .flags
= SDTL_OVERLAP
,
6233 sched_domain_topology
= tl
;
6235 sched_domains_numa_levels
= level
;
6238 static void sched_domains_numa_masks_set(int cpu
)
6241 int node
= cpu_to_node(cpu
);
6243 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6244 for (j
= 0; j
< nr_node_ids
; j
++) {
6245 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6246 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6251 static void sched_domains_numa_masks_clear(int cpu
)
6254 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6255 for (j
= 0; j
< nr_node_ids
; j
++)
6256 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6261 * Update sched_domains_numa_masks[level][node] array when new cpus
6264 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6265 unsigned long action
,
6268 int cpu
= (long)hcpu
;
6270 switch (action
& ~CPU_TASKS_FROZEN
) {
6272 sched_domains_numa_masks_set(cpu
);
6276 sched_domains_numa_masks_clear(cpu
);
6286 static inline void sched_init_numa(void)
6290 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6291 unsigned long action
,
6296 #endif /* CONFIG_NUMA */
6298 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6300 struct sched_domain_topology_level
*tl
;
6303 for_each_sd_topology(tl
) {
6304 struct sd_data
*sdd
= &tl
->data
;
6306 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6310 sdd
->sg
= alloc_percpu(struct sched_group
*);
6314 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
6318 for_each_cpu(j
, cpu_map
) {
6319 struct sched_domain
*sd
;
6320 struct sched_group
*sg
;
6321 struct sched_group_power
*sgp
;
6323 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6324 GFP_KERNEL
, cpu_to_node(j
));
6328 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6330 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6331 GFP_KERNEL
, cpu_to_node(j
));
6337 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6339 sgp
= kzalloc_node(sizeof(struct sched_group_power
) + cpumask_size(),
6340 GFP_KERNEL
, cpu_to_node(j
));
6344 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
6351 static void __sdt_free(const struct cpumask
*cpu_map
)
6353 struct sched_domain_topology_level
*tl
;
6356 for_each_sd_topology(tl
) {
6357 struct sd_data
*sdd
= &tl
->data
;
6359 for_each_cpu(j
, cpu_map
) {
6360 struct sched_domain
*sd
;
6363 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6364 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6365 free_sched_groups(sd
->groups
, 0);
6366 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6370 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6372 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
6374 free_percpu(sdd
->sd
);
6376 free_percpu(sdd
->sg
);
6378 free_percpu(sdd
->sgp
);
6383 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6384 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6385 struct sched_domain
*child
, int cpu
)
6387 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
6391 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6393 sd
->level
= child
->level
+ 1;
6394 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6398 set_domain_attribute(sd
, attr
);
6404 * Build sched domains for a given set of cpus and attach the sched domains
6405 * to the individual cpus
6407 static int build_sched_domains(const struct cpumask
*cpu_map
,
6408 struct sched_domain_attr
*attr
)
6410 enum s_alloc alloc_state
;
6411 struct sched_domain
*sd
;
6413 int i
, ret
= -ENOMEM
;
6415 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6416 if (alloc_state
!= sa_rootdomain
)
6419 /* Set up domains for cpus specified by the cpu_map. */
6420 for_each_cpu(i
, cpu_map
) {
6421 struct sched_domain_topology_level
*tl
;
6424 for_each_sd_topology(tl
) {
6425 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6426 if (tl
== sched_domain_topology
)
6427 *per_cpu_ptr(d
.sd
, i
) = sd
;
6428 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6429 sd
->flags
|= SD_OVERLAP
;
6430 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6435 /* Build the groups for the domains */
6436 for_each_cpu(i
, cpu_map
) {
6437 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6438 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6439 if (sd
->flags
& SD_OVERLAP
) {
6440 if (build_overlap_sched_groups(sd
, i
))
6443 if (build_sched_groups(sd
, i
))
6449 /* Calculate CPU power for physical packages and nodes */
6450 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6451 if (!cpumask_test_cpu(i
, cpu_map
))
6454 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6455 claim_allocations(i
, sd
);
6456 init_sched_groups_power(i
, sd
);
6460 /* Attach the domains */
6462 for_each_cpu(i
, cpu_map
) {
6463 sd
= *per_cpu_ptr(d
.sd
, i
);
6464 cpu_attach_domain(sd
, d
.rd
, i
);
6470 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6474 static cpumask_var_t
*doms_cur
; /* current sched domains */
6475 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6476 static struct sched_domain_attr
*dattr_cur
;
6477 /* attribues of custom domains in 'doms_cur' */
6480 * Special case: If a kmalloc of a doms_cur partition (array of
6481 * cpumask) fails, then fallback to a single sched domain,
6482 * as determined by the single cpumask fallback_doms.
6484 static cpumask_var_t fallback_doms
;
6487 * arch_update_cpu_topology lets virtualized architectures update the
6488 * cpu core maps. It is supposed to return 1 if the topology changed
6489 * or 0 if it stayed the same.
6491 int __weak
arch_update_cpu_topology(void)
6496 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6499 cpumask_var_t
*doms
;
6501 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6504 for (i
= 0; i
< ndoms
; i
++) {
6505 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6506 free_sched_domains(doms
, i
);
6513 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6516 for (i
= 0; i
< ndoms
; i
++)
6517 free_cpumask_var(doms
[i
]);
6522 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6523 * For now this just excludes isolated cpus, but could be used to
6524 * exclude other special cases in the future.
6526 static int init_sched_domains(const struct cpumask
*cpu_map
)
6530 arch_update_cpu_topology();
6532 doms_cur
= alloc_sched_domains(ndoms_cur
);
6534 doms_cur
= &fallback_doms
;
6535 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6536 err
= build_sched_domains(doms_cur
[0], NULL
);
6537 register_sched_domain_sysctl();
6543 * Detach sched domains from a group of cpus specified in cpu_map
6544 * These cpus will now be attached to the NULL domain
6546 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6551 for_each_cpu(i
, cpu_map
)
6552 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6556 /* handle null as "default" */
6557 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6558 struct sched_domain_attr
*new, int idx_new
)
6560 struct sched_domain_attr tmp
;
6567 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6568 new ? (new + idx_new
) : &tmp
,
6569 sizeof(struct sched_domain_attr
));
6573 * Partition sched domains as specified by the 'ndoms_new'
6574 * cpumasks in the array doms_new[] of cpumasks. This compares
6575 * doms_new[] to the current sched domain partitioning, doms_cur[].
6576 * It destroys each deleted domain and builds each new domain.
6578 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6579 * The masks don't intersect (don't overlap.) We should setup one
6580 * sched domain for each mask. CPUs not in any of the cpumasks will
6581 * not be load balanced. If the same cpumask appears both in the
6582 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6585 * The passed in 'doms_new' should be allocated using
6586 * alloc_sched_domains. This routine takes ownership of it and will
6587 * free_sched_domains it when done with it. If the caller failed the
6588 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6589 * and partition_sched_domains() will fallback to the single partition
6590 * 'fallback_doms', it also forces the domains to be rebuilt.
6592 * If doms_new == NULL it will be replaced with cpu_online_mask.
6593 * ndoms_new == 0 is a special case for destroying existing domains,
6594 * and it will not create the default domain.
6596 * Call with hotplug lock held
6598 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6599 struct sched_domain_attr
*dattr_new
)
6604 mutex_lock(&sched_domains_mutex
);
6606 /* always unregister in case we don't destroy any domains */
6607 unregister_sched_domain_sysctl();
6609 /* Let architecture update cpu core mappings. */
6610 new_topology
= arch_update_cpu_topology();
6612 n
= doms_new
? ndoms_new
: 0;
6614 /* Destroy deleted domains */
6615 for (i
= 0; i
< ndoms_cur
; i
++) {
6616 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6617 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6618 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6621 /* no match - a current sched domain not in new doms_new[] */
6622 detach_destroy_domains(doms_cur
[i
]);
6628 if (doms_new
== NULL
) {
6630 doms_new
= &fallback_doms
;
6631 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6632 WARN_ON_ONCE(dattr_new
);
6635 /* Build new domains */
6636 for (i
= 0; i
< ndoms_new
; i
++) {
6637 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6638 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6639 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6642 /* no match - add a new doms_new */
6643 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6648 /* Remember the new sched domains */
6649 if (doms_cur
!= &fallback_doms
)
6650 free_sched_domains(doms_cur
, ndoms_cur
);
6651 kfree(dattr_cur
); /* kfree(NULL) is safe */
6652 doms_cur
= doms_new
;
6653 dattr_cur
= dattr_new
;
6654 ndoms_cur
= ndoms_new
;
6656 register_sched_domain_sysctl();
6658 mutex_unlock(&sched_domains_mutex
);
6661 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6664 * Update cpusets according to cpu_active mask. If cpusets are
6665 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6666 * around partition_sched_domains().
6668 * If we come here as part of a suspend/resume, don't touch cpusets because we
6669 * want to restore it back to its original state upon resume anyway.
6671 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6675 case CPU_ONLINE_FROZEN
:
6676 case CPU_DOWN_FAILED_FROZEN
:
6679 * num_cpus_frozen tracks how many CPUs are involved in suspend
6680 * resume sequence. As long as this is not the last online
6681 * operation in the resume sequence, just build a single sched
6682 * domain, ignoring cpusets.
6685 if (likely(num_cpus_frozen
)) {
6686 partition_sched_domains(1, NULL
, NULL
);
6691 * This is the last CPU online operation. So fall through and
6692 * restore the original sched domains by considering the
6693 * cpuset configurations.
6697 case CPU_DOWN_FAILED
:
6698 cpuset_update_active_cpus(true);
6706 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6710 case CPU_DOWN_PREPARE
:
6711 cpuset_update_active_cpus(false);
6713 case CPU_DOWN_PREPARE_FROZEN
:
6715 partition_sched_domains(1, NULL
, NULL
);
6723 void __init
sched_init_smp(void)
6725 cpumask_var_t non_isolated_cpus
;
6727 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6728 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6733 * There's no userspace yet to cause hotplug operations; hence all the
6734 * cpu masks are stable and all blatant races in the below code cannot
6737 mutex_lock(&sched_domains_mutex
);
6738 init_sched_domains(cpu_active_mask
);
6739 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6740 if (cpumask_empty(non_isolated_cpus
))
6741 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6742 mutex_unlock(&sched_domains_mutex
);
6744 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
6745 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6746 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6750 /* Move init over to a non-isolated CPU */
6751 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6753 sched_init_granularity();
6754 free_cpumask_var(non_isolated_cpus
);
6756 init_sched_rt_class();
6757 init_sched_dl_class();
6760 void __init
sched_init_smp(void)
6762 sched_init_granularity();
6764 #endif /* CONFIG_SMP */
6766 const_debug
unsigned int sysctl_timer_migration
= 1;
6768 int in_sched_functions(unsigned long addr
)
6770 return in_lock_functions(addr
) ||
6771 (addr
>= (unsigned long)__sched_text_start
6772 && addr
< (unsigned long)__sched_text_end
);
6775 #ifdef CONFIG_CGROUP_SCHED
6777 * Default task group.
6778 * Every task in system belongs to this group at bootup.
6780 struct task_group root_task_group
;
6781 LIST_HEAD(task_groups
);
6784 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
6786 void __init
sched_init(void)
6789 unsigned long alloc_size
= 0, ptr
;
6791 #ifdef CONFIG_FAIR_GROUP_SCHED
6792 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6794 #ifdef CONFIG_RT_GROUP_SCHED
6795 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6797 #ifdef CONFIG_CPUMASK_OFFSTACK
6798 alloc_size
+= num_possible_cpus() * cpumask_size();
6801 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6803 #ifdef CONFIG_FAIR_GROUP_SCHED
6804 root_task_group
.se
= (struct sched_entity
**)ptr
;
6805 ptr
+= nr_cpu_ids
* sizeof(void **);
6807 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6808 ptr
+= nr_cpu_ids
* sizeof(void **);
6810 #endif /* CONFIG_FAIR_GROUP_SCHED */
6811 #ifdef CONFIG_RT_GROUP_SCHED
6812 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6813 ptr
+= nr_cpu_ids
* sizeof(void **);
6815 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6816 ptr
+= nr_cpu_ids
* sizeof(void **);
6818 #endif /* CONFIG_RT_GROUP_SCHED */
6819 #ifdef CONFIG_CPUMASK_OFFSTACK
6820 for_each_possible_cpu(i
) {
6821 per_cpu(load_balance_mask
, i
) = (void *)ptr
;
6822 ptr
+= cpumask_size();
6824 #endif /* CONFIG_CPUMASK_OFFSTACK */
6827 init_rt_bandwidth(&def_rt_bandwidth
,
6828 global_rt_period(), global_rt_runtime());
6829 init_dl_bandwidth(&def_dl_bandwidth
,
6830 global_rt_period(), global_rt_runtime());
6833 init_defrootdomain();
6836 #ifdef CONFIG_RT_GROUP_SCHED
6837 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6838 global_rt_period(), global_rt_runtime());
6839 #endif /* CONFIG_RT_GROUP_SCHED */
6841 #ifdef CONFIG_CGROUP_SCHED
6842 list_add(&root_task_group
.list
, &task_groups
);
6843 INIT_LIST_HEAD(&root_task_group
.children
);
6844 INIT_LIST_HEAD(&root_task_group
.siblings
);
6845 autogroup_init(&init_task
);
6847 #endif /* CONFIG_CGROUP_SCHED */
6849 for_each_possible_cpu(i
) {
6853 raw_spin_lock_init(&rq
->lock
);
6855 rq
->calc_load_active
= 0;
6856 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6857 init_cfs_rq(&rq
->cfs
);
6858 init_rt_rq(&rq
->rt
, rq
);
6859 init_dl_rq(&rq
->dl
, rq
);
6860 #ifdef CONFIG_FAIR_GROUP_SCHED
6861 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6862 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6864 * How much cpu bandwidth does root_task_group get?
6866 * In case of task-groups formed thr' the cgroup filesystem, it
6867 * gets 100% of the cpu resources in the system. This overall
6868 * system cpu resource is divided among the tasks of
6869 * root_task_group and its child task-groups in a fair manner,
6870 * based on each entity's (task or task-group's) weight
6871 * (se->load.weight).
6873 * In other words, if root_task_group has 10 tasks of weight
6874 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6875 * then A0's share of the cpu resource is:
6877 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6879 * We achieve this by letting root_task_group's tasks sit
6880 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6882 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6883 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6884 #endif /* CONFIG_FAIR_GROUP_SCHED */
6886 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6887 #ifdef CONFIG_RT_GROUP_SCHED
6888 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6891 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6892 rq
->cpu_load
[j
] = 0;
6894 rq
->last_load_update_tick
= jiffies
;
6899 rq
->cpu_power
= SCHED_POWER_SCALE
;
6900 rq
->post_schedule
= 0;
6901 rq
->active_balance
= 0;
6902 rq
->next_balance
= jiffies
;
6907 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
6908 rq
->max_idle_balance_cost
= sysctl_sched_migration_cost
;
6910 INIT_LIST_HEAD(&rq
->cfs_tasks
);
6912 rq_attach_root(rq
, &def_root_domain
);
6913 #ifdef CONFIG_NO_HZ_COMMON
6916 #ifdef CONFIG_NO_HZ_FULL
6917 rq
->last_sched_tick
= 0;
6921 atomic_set(&rq
->nr_iowait
, 0);
6924 set_load_weight(&init_task
);
6926 #ifdef CONFIG_PREEMPT_NOTIFIERS
6927 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
6931 * The boot idle thread does lazy MMU switching as well:
6933 atomic_inc(&init_mm
.mm_count
);
6934 enter_lazy_tlb(&init_mm
, current
);
6937 * Make us the idle thread. Technically, schedule() should not be
6938 * called from this thread, however somewhere below it might be,
6939 * but because we are the idle thread, we just pick up running again
6940 * when this runqueue becomes "idle".
6942 init_idle(current
, smp_processor_id());
6944 calc_load_update
= jiffies
+ LOAD_FREQ
;
6947 * During early bootup we pretend to be a normal task:
6949 current
->sched_class
= &fair_sched_class
;
6952 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
6953 /* May be allocated at isolcpus cmdline parse time */
6954 if (cpu_isolated_map
== NULL
)
6955 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
6956 idle_thread_set_boot_cpu();
6958 init_sched_fair_class();
6960 scheduler_running
= 1;
6963 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
6964 static inline int preempt_count_equals(int preempt_offset
)
6966 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
6968 return (nested
== preempt_offset
);
6971 void __might_sleep(const char *file
, int line
, int preempt_offset
)
6973 static unsigned long prev_jiffy
; /* ratelimiting */
6975 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
6976 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled() &&
6977 !is_idle_task(current
)) ||
6978 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
6980 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
6982 prev_jiffy
= jiffies
;
6985 "BUG: sleeping function called from invalid context at %s:%d\n",
6988 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
6989 in_atomic(), irqs_disabled(),
6990 current
->pid
, current
->comm
);
6992 debug_show_held_locks(current
);
6993 if (irqs_disabled())
6994 print_irqtrace_events(current
);
6995 #ifdef CONFIG_DEBUG_PREEMPT
6996 if (!preempt_count_equals(preempt_offset
)) {
6997 pr_err("Preemption disabled at:");
6998 print_ip_sym(current
->preempt_disable_ip
);
7004 EXPORT_SYMBOL(__might_sleep
);
7007 #ifdef CONFIG_MAGIC_SYSRQ
7008 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7010 const struct sched_class
*prev_class
= p
->sched_class
;
7011 struct sched_attr attr
= {
7012 .sched_policy
= SCHED_NORMAL
,
7014 int old_prio
= p
->prio
;
7019 dequeue_task(rq
, p
, 0);
7020 __setscheduler(rq
, p
, &attr
);
7022 enqueue_task(rq
, p
, 0);
7023 resched_task(rq
->curr
);
7026 check_class_changed(rq
, p
, prev_class
, old_prio
);
7029 void normalize_rt_tasks(void)
7031 struct task_struct
*g
, *p
;
7032 unsigned long flags
;
7035 read_lock_irqsave(&tasklist_lock
, flags
);
7036 do_each_thread(g
, p
) {
7038 * Only normalize user tasks:
7043 p
->se
.exec_start
= 0;
7044 #ifdef CONFIG_SCHEDSTATS
7045 p
->se
.statistics
.wait_start
= 0;
7046 p
->se
.statistics
.sleep_start
= 0;
7047 p
->se
.statistics
.block_start
= 0;
7050 if (!dl_task(p
) && !rt_task(p
)) {
7052 * Renice negative nice level userspace
7055 if (task_nice(p
) < 0 && p
->mm
)
7056 set_user_nice(p
, 0);
7060 raw_spin_lock(&p
->pi_lock
);
7061 rq
= __task_rq_lock(p
);
7063 normalize_task(rq
, p
);
7065 __task_rq_unlock(rq
);
7066 raw_spin_unlock(&p
->pi_lock
);
7067 } while_each_thread(g
, p
);
7069 read_unlock_irqrestore(&tasklist_lock
, flags
);
7072 #endif /* CONFIG_MAGIC_SYSRQ */
7074 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7076 * These functions are only useful for the IA64 MCA handling, or kdb.
7078 * They can only be called when the whole system has been
7079 * stopped - every CPU needs to be quiescent, and no scheduling
7080 * activity can take place. Using them for anything else would
7081 * be a serious bug, and as a result, they aren't even visible
7082 * under any other configuration.
7086 * curr_task - return the current task for a given cpu.
7087 * @cpu: the processor in question.
7089 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7091 * Return: The current task for @cpu.
7093 struct task_struct
*curr_task(int cpu
)
7095 return cpu_curr(cpu
);
7098 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7102 * set_curr_task - set the current task for a given cpu.
7103 * @cpu: the processor in question.
7104 * @p: the task pointer to set.
7106 * Description: This function must only be used when non-maskable interrupts
7107 * are serviced on a separate stack. It allows the architecture to switch the
7108 * notion of the current task on a cpu in a non-blocking manner. This function
7109 * must be called with all CPU's synchronized, and interrupts disabled, the
7110 * and caller must save the original value of the current task (see
7111 * curr_task() above) and restore that value before reenabling interrupts and
7112 * re-starting the system.
7114 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7116 void set_curr_task(int cpu
, struct task_struct
*p
)
7123 #ifdef CONFIG_CGROUP_SCHED
7124 /* task_group_lock serializes the addition/removal of task groups */
7125 static DEFINE_SPINLOCK(task_group_lock
);
7127 static void free_sched_group(struct task_group
*tg
)
7129 free_fair_sched_group(tg
);
7130 free_rt_sched_group(tg
);
7135 /* allocate runqueue etc for a new task group */
7136 struct task_group
*sched_create_group(struct task_group
*parent
)
7138 struct task_group
*tg
;
7140 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7142 return ERR_PTR(-ENOMEM
);
7144 if (!alloc_fair_sched_group(tg
, parent
))
7147 if (!alloc_rt_sched_group(tg
, parent
))
7153 free_sched_group(tg
);
7154 return ERR_PTR(-ENOMEM
);
7157 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
7159 unsigned long flags
;
7161 spin_lock_irqsave(&task_group_lock
, flags
);
7162 list_add_rcu(&tg
->list
, &task_groups
);
7164 WARN_ON(!parent
); /* root should already exist */
7166 tg
->parent
= parent
;
7167 INIT_LIST_HEAD(&tg
->children
);
7168 list_add_rcu(&tg
->siblings
, &parent
->children
);
7169 spin_unlock_irqrestore(&task_group_lock
, flags
);
7172 /* rcu callback to free various structures associated with a task group */
7173 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7175 /* now it should be safe to free those cfs_rqs */
7176 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7179 /* Destroy runqueue etc associated with a task group */
7180 void sched_destroy_group(struct task_group
*tg
)
7182 /* wait for possible concurrent references to cfs_rqs complete */
7183 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7186 void sched_offline_group(struct task_group
*tg
)
7188 unsigned long flags
;
7191 /* end participation in shares distribution */
7192 for_each_possible_cpu(i
)
7193 unregister_fair_sched_group(tg
, i
);
7195 spin_lock_irqsave(&task_group_lock
, flags
);
7196 list_del_rcu(&tg
->list
);
7197 list_del_rcu(&tg
->siblings
);
7198 spin_unlock_irqrestore(&task_group_lock
, flags
);
7201 /* change task's runqueue when it moves between groups.
7202 * The caller of this function should have put the task in its new group
7203 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7204 * reflect its new group.
7206 void sched_move_task(struct task_struct
*tsk
)
7208 struct task_group
*tg
;
7210 unsigned long flags
;
7213 rq
= task_rq_lock(tsk
, &flags
);
7215 running
= task_current(rq
, tsk
);
7219 dequeue_task(rq
, tsk
, 0);
7220 if (unlikely(running
))
7221 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7223 tg
= container_of(task_css_check(tsk
, cpu_cgrp_id
,
7224 lockdep_is_held(&tsk
->sighand
->siglock
)),
7225 struct task_group
, css
);
7226 tg
= autogroup_task_group(tsk
, tg
);
7227 tsk
->sched_task_group
= tg
;
7229 #ifdef CONFIG_FAIR_GROUP_SCHED
7230 if (tsk
->sched_class
->task_move_group
)
7231 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
7234 set_task_rq(tsk
, task_cpu(tsk
));
7236 if (unlikely(running
))
7237 tsk
->sched_class
->set_curr_task(rq
);
7239 enqueue_task(rq
, tsk
, 0);
7241 task_rq_unlock(rq
, tsk
, &flags
);
7243 #endif /* CONFIG_CGROUP_SCHED */
7245 #ifdef CONFIG_RT_GROUP_SCHED
7247 * Ensure that the real time constraints are schedulable.
7249 static DEFINE_MUTEX(rt_constraints_mutex
);
7251 /* Must be called with tasklist_lock held */
7252 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7254 struct task_struct
*g
, *p
;
7256 do_each_thread(g
, p
) {
7257 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
7259 } while_each_thread(g
, p
);
7264 struct rt_schedulable_data
{
7265 struct task_group
*tg
;
7270 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7272 struct rt_schedulable_data
*d
= data
;
7273 struct task_group
*child
;
7274 unsigned long total
, sum
= 0;
7275 u64 period
, runtime
;
7277 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7278 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7281 period
= d
->rt_period
;
7282 runtime
= d
->rt_runtime
;
7286 * Cannot have more runtime than the period.
7288 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7292 * Ensure we don't starve existing RT tasks.
7294 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7297 total
= to_ratio(period
, runtime
);
7300 * Nobody can have more than the global setting allows.
7302 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7306 * The sum of our children's runtime should not exceed our own.
7308 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7309 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7310 runtime
= child
->rt_bandwidth
.rt_runtime
;
7312 if (child
== d
->tg
) {
7313 period
= d
->rt_period
;
7314 runtime
= d
->rt_runtime
;
7317 sum
+= to_ratio(period
, runtime
);
7326 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7330 struct rt_schedulable_data data
= {
7332 .rt_period
= period
,
7333 .rt_runtime
= runtime
,
7337 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7343 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7344 u64 rt_period
, u64 rt_runtime
)
7348 mutex_lock(&rt_constraints_mutex
);
7349 read_lock(&tasklist_lock
);
7350 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7354 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7355 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7356 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7358 for_each_possible_cpu(i
) {
7359 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7361 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7362 rt_rq
->rt_runtime
= rt_runtime
;
7363 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7365 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7367 read_unlock(&tasklist_lock
);
7368 mutex_unlock(&rt_constraints_mutex
);
7373 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7375 u64 rt_runtime
, rt_period
;
7377 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7378 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7379 if (rt_runtime_us
< 0)
7380 rt_runtime
= RUNTIME_INF
;
7382 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7385 static long sched_group_rt_runtime(struct task_group
*tg
)
7389 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7392 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7393 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7394 return rt_runtime_us
;
7397 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7399 u64 rt_runtime
, rt_period
;
7401 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7402 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7407 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7410 static long sched_group_rt_period(struct task_group
*tg
)
7414 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7415 do_div(rt_period_us
, NSEC_PER_USEC
);
7416 return rt_period_us
;
7418 #endif /* CONFIG_RT_GROUP_SCHED */
7420 #ifdef CONFIG_RT_GROUP_SCHED
7421 static int sched_rt_global_constraints(void)
7425 mutex_lock(&rt_constraints_mutex
);
7426 read_lock(&tasklist_lock
);
7427 ret
= __rt_schedulable(NULL
, 0, 0);
7428 read_unlock(&tasklist_lock
);
7429 mutex_unlock(&rt_constraints_mutex
);
7434 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7436 /* Don't accept realtime tasks when there is no way for them to run */
7437 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7443 #else /* !CONFIG_RT_GROUP_SCHED */
7444 static int sched_rt_global_constraints(void)
7446 unsigned long flags
;
7449 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7450 for_each_possible_cpu(i
) {
7451 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7453 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7454 rt_rq
->rt_runtime
= global_rt_runtime();
7455 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7457 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7461 #endif /* CONFIG_RT_GROUP_SCHED */
7463 static int sched_dl_global_constraints(void)
7465 u64 runtime
= global_rt_runtime();
7466 u64 period
= global_rt_period();
7467 u64 new_bw
= to_ratio(period
, runtime
);
7469 unsigned long flags
;
7472 * Here we want to check the bandwidth not being set to some
7473 * value smaller than the currently allocated bandwidth in
7474 * any of the root_domains.
7476 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7477 * cycling on root_domains... Discussion on different/better
7478 * solutions is welcome!
7480 for_each_possible_cpu(cpu
) {
7481 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
7483 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7484 if (new_bw
< dl_b
->total_bw
)
7486 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7495 static void sched_dl_do_global(void)
7499 unsigned long flags
;
7501 def_dl_bandwidth
.dl_period
= global_rt_period();
7502 def_dl_bandwidth
.dl_runtime
= global_rt_runtime();
7504 if (global_rt_runtime() != RUNTIME_INF
)
7505 new_bw
= to_ratio(global_rt_period(), global_rt_runtime());
7508 * FIXME: As above...
7510 for_each_possible_cpu(cpu
) {
7511 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
7513 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7515 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7519 static int sched_rt_global_validate(void)
7521 if (sysctl_sched_rt_period
<= 0)
7524 if ((sysctl_sched_rt_runtime
!= RUNTIME_INF
) &&
7525 (sysctl_sched_rt_runtime
> sysctl_sched_rt_period
))
7531 static void sched_rt_do_global(void)
7533 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7534 def_rt_bandwidth
.rt_period
= ns_to_ktime(global_rt_period());
7537 int sched_rt_handler(struct ctl_table
*table
, int write
,
7538 void __user
*buffer
, size_t *lenp
,
7541 int old_period
, old_runtime
;
7542 static DEFINE_MUTEX(mutex
);
7546 old_period
= sysctl_sched_rt_period
;
7547 old_runtime
= sysctl_sched_rt_runtime
;
7549 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7551 if (!ret
&& write
) {
7552 ret
= sched_rt_global_validate();
7556 ret
= sched_rt_global_constraints();
7560 ret
= sched_dl_global_constraints();
7564 sched_rt_do_global();
7565 sched_dl_do_global();
7569 sysctl_sched_rt_period
= old_period
;
7570 sysctl_sched_rt_runtime
= old_runtime
;
7572 mutex_unlock(&mutex
);
7577 int sched_rr_handler(struct ctl_table
*table
, int write
,
7578 void __user
*buffer
, size_t *lenp
,
7582 static DEFINE_MUTEX(mutex
);
7585 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7586 /* make sure that internally we keep jiffies */
7587 /* also, writing zero resets timeslice to default */
7588 if (!ret
&& write
) {
7589 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7590 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7592 mutex_unlock(&mutex
);
7596 #ifdef CONFIG_CGROUP_SCHED
7598 static inline struct task_group
*css_tg(struct cgroup_subsys_state
*css
)
7600 return css
? container_of(css
, struct task_group
, css
) : NULL
;
7603 static struct cgroup_subsys_state
*
7604 cpu_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
7606 struct task_group
*parent
= css_tg(parent_css
);
7607 struct task_group
*tg
;
7610 /* This is early initialization for the top cgroup */
7611 return &root_task_group
.css
;
7614 tg
= sched_create_group(parent
);
7616 return ERR_PTR(-ENOMEM
);
7621 static int cpu_cgroup_css_online(struct cgroup_subsys_state
*css
)
7623 struct task_group
*tg
= css_tg(css
);
7624 struct task_group
*parent
= css_tg(css_parent(css
));
7627 sched_online_group(tg
, parent
);
7631 static void cpu_cgroup_css_free(struct cgroup_subsys_state
*css
)
7633 struct task_group
*tg
= css_tg(css
);
7635 sched_destroy_group(tg
);
7638 static void cpu_cgroup_css_offline(struct cgroup_subsys_state
*css
)
7640 struct task_group
*tg
= css_tg(css
);
7642 sched_offline_group(tg
);
7645 static int cpu_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7646 struct cgroup_taskset
*tset
)
7648 struct task_struct
*task
;
7650 cgroup_taskset_for_each(task
, tset
) {
7651 #ifdef CONFIG_RT_GROUP_SCHED
7652 if (!sched_rt_can_attach(css_tg(css
), task
))
7655 /* We don't support RT-tasks being in separate groups */
7656 if (task
->sched_class
!= &fair_sched_class
)
7663 static void cpu_cgroup_attach(struct cgroup_subsys_state
*css
,
7664 struct cgroup_taskset
*tset
)
7666 struct task_struct
*task
;
7668 cgroup_taskset_for_each(task
, tset
)
7669 sched_move_task(task
);
7672 static void cpu_cgroup_exit(struct cgroup_subsys_state
*css
,
7673 struct cgroup_subsys_state
*old_css
,
7674 struct task_struct
*task
)
7677 * cgroup_exit() is called in the copy_process() failure path.
7678 * Ignore this case since the task hasn't ran yet, this avoids
7679 * trying to poke a half freed task state from generic code.
7681 if (!(task
->flags
& PF_EXITING
))
7684 sched_move_task(task
);
7687 #ifdef CONFIG_FAIR_GROUP_SCHED
7688 static int cpu_shares_write_u64(struct cgroup_subsys_state
*css
,
7689 struct cftype
*cftype
, u64 shareval
)
7691 return sched_group_set_shares(css_tg(css
), scale_load(shareval
));
7694 static u64
cpu_shares_read_u64(struct cgroup_subsys_state
*css
,
7697 struct task_group
*tg
= css_tg(css
);
7699 return (u64
) scale_load_down(tg
->shares
);
7702 #ifdef CONFIG_CFS_BANDWIDTH
7703 static DEFINE_MUTEX(cfs_constraints_mutex
);
7705 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7706 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7708 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7710 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7712 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7713 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7715 if (tg
== &root_task_group
)
7719 * Ensure we have at some amount of bandwidth every period. This is
7720 * to prevent reaching a state of large arrears when throttled via
7721 * entity_tick() resulting in prolonged exit starvation.
7723 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7727 * Likewise, bound things on the otherside by preventing insane quota
7728 * periods. This also allows us to normalize in computing quota
7731 if (period
> max_cfs_quota_period
)
7734 mutex_lock(&cfs_constraints_mutex
);
7735 ret
= __cfs_schedulable(tg
, period
, quota
);
7739 runtime_enabled
= quota
!= RUNTIME_INF
;
7740 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7742 * If we need to toggle cfs_bandwidth_used, off->on must occur
7743 * before making related changes, and on->off must occur afterwards
7745 if (runtime_enabled
&& !runtime_was_enabled
)
7746 cfs_bandwidth_usage_inc();
7747 raw_spin_lock_irq(&cfs_b
->lock
);
7748 cfs_b
->period
= ns_to_ktime(period
);
7749 cfs_b
->quota
= quota
;
7751 __refill_cfs_bandwidth_runtime(cfs_b
);
7752 /* restart the period timer (if active) to handle new period expiry */
7753 if (runtime_enabled
&& cfs_b
->timer_active
) {
7754 /* force a reprogram */
7755 cfs_b
->timer_active
= 0;
7756 __start_cfs_bandwidth(cfs_b
);
7758 raw_spin_unlock_irq(&cfs_b
->lock
);
7760 for_each_possible_cpu(i
) {
7761 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7762 struct rq
*rq
= cfs_rq
->rq
;
7764 raw_spin_lock_irq(&rq
->lock
);
7765 cfs_rq
->runtime_enabled
= runtime_enabled
;
7766 cfs_rq
->runtime_remaining
= 0;
7768 if (cfs_rq
->throttled
)
7769 unthrottle_cfs_rq(cfs_rq
);
7770 raw_spin_unlock_irq(&rq
->lock
);
7772 if (runtime_was_enabled
&& !runtime_enabled
)
7773 cfs_bandwidth_usage_dec();
7775 mutex_unlock(&cfs_constraints_mutex
);
7780 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7784 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7785 if (cfs_quota_us
< 0)
7786 quota
= RUNTIME_INF
;
7788 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7790 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7793 long tg_get_cfs_quota(struct task_group
*tg
)
7797 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7800 quota_us
= tg
->cfs_bandwidth
.quota
;
7801 do_div(quota_us
, NSEC_PER_USEC
);
7806 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7810 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7811 quota
= tg
->cfs_bandwidth
.quota
;
7813 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7816 long tg_get_cfs_period(struct task_group
*tg
)
7820 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7821 do_div(cfs_period_us
, NSEC_PER_USEC
);
7823 return cfs_period_us
;
7826 static s64
cpu_cfs_quota_read_s64(struct cgroup_subsys_state
*css
,
7829 return tg_get_cfs_quota(css_tg(css
));
7832 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state
*css
,
7833 struct cftype
*cftype
, s64 cfs_quota_us
)
7835 return tg_set_cfs_quota(css_tg(css
), cfs_quota_us
);
7838 static u64
cpu_cfs_period_read_u64(struct cgroup_subsys_state
*css
,
7841 return tg_get_cfs_period(css_tg(css
));
7844 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state
*css
,
7845 struct cftype
*cftype
, u64 cfs_period_us
)
7847 return tg_set_cfs_period(css_tg(css
), cfs_period_us
);
7850 struct cfs_schedulable_data
{
7851 struct task_group
*tg
;
7856 * normalize group quota/period to be quota/max_period
7857 * note: units are usecs
7859 static u64
normalize_cfs_quota(struct task_group
*tg
,
7860 struct cfs_schedulable_data
*d
)
7868 period
= tg_get_cfs_period(tg
);
7869 quota
= tg_get_cfs_quota(tg
);
7872 /* note: these should typically be equivalent */
7873 if (quota
== RUNTIME_INF
|| quota
== -1)
7876 return to_ratio(period
, quota
);
7879 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7881 struct cfs_schedulable_data
*d
= data
;
7882 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7883 s64 quota
= 0, parent_quota
= -1;
7886 quota
= RUNTIME_INF
;
7888 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
7890 quota
= normalize_cfs_quota(tg
, d
);
7891 parent_quota
= parent_b
->hierarchal_quota
;
7894 * ensure max(child_quota) <= parent_quota, inherit when no
7897 if (quota
== RUNTIME_INF
)
7898 quota
= parent_quota
;
7899 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
7902 cfs_b
->hierarchal_quota
= quota
;
7907 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
7910 struct cfs_schedulable_data data
= {
7916 if (quota
!= RUNTIME_INF
) {
7917 do_div(data
.period
, NSEC_PER_USEC
);
7918 do_div(data
.quota
, NSEC_PER_USEC
);
7922 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
7928 static int cpu_stats_show(struct seq_file
*sf
, void *v
)
7930 struct task_group
*tg
= css_tg(seq_css(sf
));
7931 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7933 seq_printf(sf
, "nr_periods %d\n", cfs_b
->nr_periods
);
7934 seq_printf(sf
, "nr_throttled %d\n", cfs_b
->nr_throttled
);
7935 seq_printf(sf
, "throttled_time %llu\n", cfs_b
->throttled_time
);
7939 #endif /* CONFIG_CFS_BANDWIDTH */
7940 #endif /* CONFIG_FAIR_GROUP_SCHED */
7942 #ifdef CONFIG_RT_GROUP_SCHED
7943 static int cpu_rt_runtime_write(struct cgroup_subsys_state
*css
,
7944 struct cftype
*cft
, s64 val
)
7946 return sched_group_set_rt_runtime(css_tg(css
), val
);
7949 static s64
cpu_rt_runtime_read(struct cgroup_subsys_state
*css
,
7952 return sched_group_rt_runtime(css_tg(css
));
7955 static int cpu_rt_period_write_uint(struct cgroup_subsys_state
*css
,
7956 struct cftype
*cftype
, u64 rt_period_us
)
7958 return sched_group_set_rt_period(css_tg(css
), rt_period_us
);
7961 static u64
cpu_rt_period_read_uint(struct cgroup_subsys_state
*css
,
7964 return sched_group_rt_period(css_tg(css
));
7966 #endif /* CONFIG_RT_GROUP_SCHED */
7968 static struct cftype cpu_files
[] = {
7969 #ifdef CONFIG_FAIR_GROUP_SCHED
7972 .read_u64
= cpu_shares_read_u64
,
7973 .write_u64
= cpu_shares_write_u64
,
7976 #ifdef CONFIG_CFS_BANDWIDTH
7978 .name
= "cfs_quota_us",
7979 .read_s64
= cpu_cfs_quota_read_s64
,
7980 .write_s64
= cpu_cfs_quota_write_s64
,
7983 .name
= "cfs_period_us",
7984 .read_u64
= cpu_cfs_period_read_u64
,
7985 .write_u64
= cpu_cfs_period_write_u64
,
7989 .seq_show
= cpu_stats_show
,
7992 #ifdef CONFIG_RT_GROUP_SCHED
7994 .name
= "rt_runtime_us",
7995 .read_s64
= cpu_rt_runtime_read
,
7996 .write_s64
= cpu_rt_runtime_write
,
7999 .name
= "rt_period_us",
8000 .read_u64
= cpu_rt_period_read_uint
,
8001 .write_u64
= cpu_rt_period_write_uint
,
8007 struct cgroup_subsys cpu_cgrp_subsys
= {
8008 .css_alloc
= cpu_cgroup_css_alloc
,
8009 .css_free
= cpu_cgroup_css_free
,
8010 .css_online
= cpu_cgroup_css_online
,
8011 .css_offline
= cpu_cgroup_css_offline
,
8012 .can_attach
= cpu_cgroup_can_attach
,
8013 .attach
= cpu_cgroup_attach
,
8014 .exit
= cpu_cgroup_exit
,
8015 .base_cftypes
= cpu_files
,
8019 #endif /* CONFIG_CGROUP_SCHED */
8021 void dump_cpu_task(int cpu
)
8023 pr_info("Task dump for CPU %d:\n", cpu
);
8024 sched_show_task(cpu_curr(cpu
));