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 #ifdef smp_mb__before_atomic
94 void __smp_mb__before_atomic(void)
96 smp_mb__before_atomic();
98 EXPORT_SYMBOL(__smp_mb__before_atomic
);
101 #ifdef smp_mb__after_atomic
102 void __smp_mb__after_atomic(void)
104 smp_mb__after_atomic();
106 EXPORT_SYMBOL(__smp_mb__after_atomic
);
109 void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
112 ktime_t soft
, hard
, now
;
115 if (hrtimer_active(period_timer
))
118 now
= hrtimer_cb_get_time(period_timer
);
119 hrtimer_forward(period_timer
, now
, period
);
121 soft
= hrtimer_get_softexpires(period_timer
);
122 hard
= hrtimer_get_expires(period_timer
);
123 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
124 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
125 HRTIMER_MODE_ABS_PINNED
, 0);
129 DEFINE_MUTEX(sched_domains_mutex
);
130 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
132 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
134 void update_rq_clock(struct rq
*rq
)
138 if (rq
->skip_clock_update
> 0)
141 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
145 update_rq_clock_task(rq
, delta
);
149 * Debugging: various feature bits
152 #define SCHED_FEAT(name, enabled) \
153 (1UL << __SCHED_FEAT_##name) * enabled |
155 const_debug
unsigned int sysctl_sched_features
=
156 #include "features.h"
161 #ifdef CONFIG_SCHED_DEBUG
162 #define SCHED_FEAT(name, enabled) \
165 static const char * const sched_feat_names
[] = {
166 #include "features.h"
171 static int sched_feat_show(struct seq_file
*m
, void *v
)
175 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
176 if (!(sysctl_sched_features
& (1UL << i
)))
178 seq_printf(m
, "%s ", sched_feat_names
[i
]);
185 #ifdef HAVE_JUMP_LABEL
187 #define jump_label_key__true STATIC_KEY_INIT_TRUE
188 #define jump_label_key__false STATIC_KEY_INIT_FALSE
190 #define SCHED_FEAT(name, enabled) \
191 jump_label_key__##enabled ,
193 struct static_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
194 #include "features.h"
199 static void sched_feat_disable(int i
)
201 if (static_key_enabled(&sched_feat_keys
[i
]))
202 static_key_slow_dec(&sched_feat_keys
[i
]);
205 static void sched_feat_enable(int i
)
207 if (!static_key_enabled(&sched_feat_keys
[i
]))
208 static_key_slow_inc(&sched_feat_keys
[i
]);
211 static void sched_feat_disable(int i
) { };
212 static void sched_feat_enable(int i
) { };
213 #endif /* HAVE_JUMP_LABEL */
215 static int sched_feat_set(char *cmp
)
220 if (strncmp(cmp
, "NO_", 3) == 0) {
225 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
226 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
228 sysctl_sched_features
&= ~(1UL << i
);
229 sched_feat_disable(i
);
231 sysctl_sched_features
|= (1UL << i
);
232 sched_feat_enable(i
);
242 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
243 size_t cnt
, loff_t
*ppos
)
253 if (copy_from_user(&buf
, ubuf
, cnt
))
259 /* Ensure the static_key remains in a consistent state */
260 inode
= file_inode(filp
);
261 mutex_lock(&inode
->i_mutex
);
262 i
= sched_feat_set(cmp
);
263 mutex_unlock(&inode
->i_mutex
);
264 if (i
== __SCHED_FEAT_NR
)
272 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
274 return single_open(filp
, sched_feat_show
, NULL
);
277 static const struct file_operations sched_feat_fops
= {
278 .open
= sched_feat_open
,
279 .write
= sched_feat_write
,
282 .release
= single_release
,
285 static __init
int sched_init_debug(void)
287 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
292 late_initcall(sched_init_debug
);
293 #endif /* CONFIG_SCHED_DEBUG */
296 * Number of tasks to iterate in a single balance run.
297 * Limited because this is done with IRQs disabled.
299 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
302 * period over which we average the RT time consumption, measured
307 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
310 * period over which we measure -rt task cpu usage in us.
313 unsigned int sysctl_sched_rt_period
= 1000000;
315 __read_mostly
int scheduler_running
;
318 * part of the period that we allow rt tasks to run in us.
321 int sysctl_sched_rt_runtime
= 950000;
324 * __task_rq_lock - lock the rq @p resides on.
326 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
331 lockdep_assert_held(&p
->pi_lock
);
335 raw_spin_lock(&rq
->lock
);
336 if (likely(rq
== task_rq(p
)))
338 raw_spin_unlock(&rq
->lock
);
343 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
345 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
346 __acquires(p
->pi_lock
)
352 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
354 raw_spin_lock(&rq
->lock
);
355 if (likely(rq
== task_rq(p
)))
357 raw_spin_unlock(&rq
->lock
);
358 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
362 static void __task_rq_unlock(struct rq
*rq
)
365 raw_spin_unlock(&rq
->lock
);
369 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
371 __releases(p
->pi_lock
)
373 raw_spin_unlock(&rq
->lock
);
374 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
378 * this_rq_lock - lock this runqueue and disable interrupts.
380 static struct rq
*this_rq_lock(void)
387 raw_spin_lock(&rq
->lock
);
392 #ifdef CONFIG_SCHED_HRTICK
394 * Use HR-timers to deliver accurate preemption points.
397 static void hrtick_clear(struct rq
*rq
)
399 if (hrtimer_active(&rq
->hrtick_timer
))
400 hrtimer_cancel(&rq
->hrtick_timer
);
404 * High-resolution timer tick.
405 * Runs from hardirq context with interrupts disabled.
407 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
409 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
411 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
413 raw_spin_lock(&rq
->lock
);
415 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
416 raw_spin_unlock(&rq
->lock
);
418 return HRTIMER_NORESTART
;
423 static int __hrtick_restart(struct rq
*rq
)
425 struct hrtimer
*timer
= &rq
->hrtick_timer
;
426 ktime_t time
= hrtimer_get_softexpires(timer
);
428 return __hrtimer_start_range_ns(timer
, time
, 0, HRTIMER_MODE_ABS_PINNED
, 0);
432 * called from hardirq (IPI) context
434 static void __hrtick_start(void *arg
)
438 raw_spin_lock(&rq
->lock
);
439 __hrtick_restart(rq
);
440 rq
->hrtick_csd_pending
= 0;
441 raw_spin_unlock(&rq
->lock
);
445 * Called to set the hrtick timer state.
447 * called with rq->lock held and irqs disabled
449 void hrtick_start(struct rq
*rq
, u64 delay
)
451 struct hrtimer
*timer
= &rq
->hrtick_timer
;
452 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
454 hrtimer_set_expires(timer
, time
);
456 if (rq
== this_rq()) {
457 __hrtick_restart(rq
);
458 } else if (!rq
->hrtick_csd_pending
) {
459 smp_call_function_single_async(cpu_of(rq
), &rq
->hrtick_csd
);
460 rq
->hrtick_csd_pending
= 1;
465 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
467 int cpu
= (int)(long)hcpu
;
470 case CPU_UP_CANCELED
:
471 case CPU_UP_CANCELED_FROZEN
:
472 case CPU_DOWN_PREPARE
:
473 case CPU_DOWN_PREPARE_FROZEN
:
475 case CPU_DEAD_FROZEN
:
476 hrtick_clear(cpu_rq(cpu
));
483 static __init
void init_hrtick(void)
485 hotcpu_notifier(hotplug_hrtick
, 0);
489 * Called to set the hrtick timer state.
491 * called with rq->lock held and irqs disabled
493 void hrtick_start(struct rq
*rq
, u64 delay
)
495 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
496 HRTIMER_MODE_REL_PINNED
, 0);
499 static inline void init_hrtick(void)
502 #endif /* CONFIG_SMP */
504 static void init_rq_hrtick(struct rq
*rq
)
507 rq
->hrtick_csd_pending
= 0;
509 rq
->hrtick_csd
.flags
= 0;
510 rq
->hrtick_csd
.func
= __hrtick_start
;
511 rq
->hrtick_csd
.info
= rq
;
514 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
515 rq
->hrtick_timer
.function
= hrtick
;
517 #else /* CONFIG_SCHED_HRTICK */
518 static inline void hrtick_clear(struct rq
*rq
)
522 static inline void init_rq_hrtick(struct rq
*rq
)
526 static inline void init_hrtick(void)
529 #endif /* CONFIG_SCHED_HRTICK */
532 * cmpxchg based fetch_or, macro so it works for different integer types
534 #define fetch_or(ptr, val) \
535 ({ typeof(*(ptr)) __old, __val = *(ptr); \
537 __old = cmpxchg((ptr), __val, __val | (val)); \
538 if (__old == __val) \
545 #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
547 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
548 * this avoids any races wrt polling state changes and thereby avoids
551 static bool set_nr_and_not_polling(struct task_struct
*p
)
553 struct thread_info
*ti
= task_thread_info(p
);
554 return !(fetch_or(&ti
->flags
, _TIF_NEED_RESCHED
) & _TIF_POLLING_NRFLAG
);
558 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
560 * If this returns true, then the idle task promises to call
561 * sched_ttwu_pending() and reschedule soon.
563 static bool set_nr_if_polling(struct task_struct
*p
)
565 struct thread_info
*ti
= task_thread_info(p
);
566 typeof(ti
->flags
) old
, val
= ACCESS_ONCE(ti
->flags
);
569 if (!(val
& _TIF_POLLING_NRFLAG
))
571 if (val
& _TIF_NEED_RESCHED
)
573 old
= cmpxchg(&ti
->flags
, val
, val
| _TIF_NEED_RESCHED
);
582 static bool set_nr_and_not_polling(struct task_struct
*p
)
584 set_tsk_need_resched(p
);
589 static bool set_nr_if_polling(struct task_struct
*p
)
597 * resched_curr - mark rq's current task 'to be rescheduled now'.
599 * On UP this means the setting of the need_resched flag, on SMP it
600 * might also involve a cross-CPU call to trigger the scheduler on
603 void resched_curr(struct rq
*rq
)
605 struct task_struct
*curr
= rq
->curr
;
608 lockdep_assert_held(&rq
->lock
);
610 if (test_tsk_need_resched(curr
))
615 if (cpu
== smp_processor_id()) {
616 set_tsk_need_resched(curr
);
617 set_preempt_need_resched();
621 if (set_nr_and_not_polling(curr
))
622 smp_send_reschedule(cpu
);
624 trace_sched_wake_idle_without_ipi(cpu
);
627 void resched_cpu(int cpu
)
629 struct rq
*rq
= cpu_rq(cpu
);
632 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
635 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
639 #ifdef CONFIG_NO_HZ_COMMON
641 * In the semi idle case, use the nearest busy cpu for migrating timers
642 * from an idle cpu. This is good for power-savings.
644 * We don't do similar optimization for completely idle system, as
645 * selecting an idle cpu will add more delays to the timers than intended
646 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
648 int get_nohz_timer_target(int pinned
)
650 int cpu
= smp_processor_id();
652 struct sched_domain
*sd
;
654 if (pinned
|| !get_sysctl_timer_migration() || !idle_cpu(cpu
))
658 for_each_domain(cpu
, sd
) {
659 for_each_cpu(i
, sched_domain_span(sd
)) {
671 * When add_timer_on() enqueues a timer into the timer wheel of an
672 * idle CPU then this timer might expire before the next timer event
673 * which is scheduled to wake up that CPU. In case of a completely
674 * idle system the next event might even be infinite time into the
675 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
676 * leaves the inner idle loop so the newly added timer is taken into
677 * account when the CPU goes back to idle and evaluates the timer
678 * wheel for the next timer event.
680 static void wake_up_idle_cpu(int cpu
)
682 struct rq
*rq
= cpu_rq(cpu
);
684 if (cpu
== smp_processor_id())
687 if (set_nr_and_not_polling(rq
->idle
))
688 smp_send_reschedule(cpu
);
690 trace_sched_wake_idle_without_ipi(cpu
);
693 static bool wake_up_full_nohz_cpu(int cpu
)
696 * We just need the target to call irq_exit() and re-evaluate
697 * the next tick. The nohz full kick at least implies that.
698 * If needed we can still optimize that later with an
701 if (tick_nohz_full_cpu(cpu
)) {
702 if (cpu
!= smp_processor_id() ||
703 tick_nohz_tick_stopped())
704 tick_nohz_full_kick_cpu(cpu
);
711 void wake_up_nohz_cpu(int cpu
)
713 if (!wake_up_full_nohz_cpu(cpu
))
714 wake_up_idle_cpu(cpu
);
717 static inline bool got_nohz_idle_kick(void)
719 int cpu
= smp_processor_id();
721 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
724 if (idle_cpu(cpu
) && !need_resched())
728 * We can't run Idle Load Balance on this CPU for this time so we
729 * cancel it and clear NOHZ_BALANCE_KICK
731 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
735 #else /* CONFIG_NO_HZ_COMMON */
737 static inline bool got_nohz_idle_kick(void)
742 #endif /* CONFIG_NO_HZ_COMMON */
744 #ifdef CONFIG_NO_HZ_FULL
745 bool sched_can_stop_tick(void)
748 * More than one running task need preemption.
749 * nr_running update is assumed to be visible
750 * after IPI is sent from wakers.
752 if (this_rq()->nr_running
> 1)
757 #endif /* CONFIG_NO_HZ_FULL */
759 void sched_avg_update(struct rq
*rq
)
761 s64 period
= sched_avg_period();
763 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
765 * Inline assembly required to prevent the compiler
766 * optimising this loop into a divmod call.
767 * See __iter_div_u64_rem() for another example of this.
769 asm("" : "+rm" (rq
->age_stamp
));
770 rq
->age_stamp
+= period
;
775 #endif /* CONFIG_SMP */
777 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
778 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
780 * Iterate task_group tree rooted at *from, calling @down when first entering a
781 * node and @up when leaving it for the final time.
783 * Caller must hold rcu_lock or sufficient equivalent.
785 int walk_tg_tree_from(struct task_group
*from
,
786 tg_visitor down
, tg_visitor up
, void *data
)
788 struct task_group
*parent
, *child
;
794 ret
= (*down
)(parent
, data
);
797 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
804 ret
= (*up
)(parent
, data
);
805 if (ret
|| parent
== from
)
809 parent
= parent
->parent
;
816 int tg_nop(struct task_group
*tg
, void *data
)
822 static void set_load_weight(struct task_struct
*p
)
824 int prio
= p
->static_prio
- MAX_RT_PRIO
;
825 struct load_weight
*load
= &p
->se
.load
;
828 * SCHED_IDLE tasks get minimal weight:
830 if (p
->policy
== SCHED_IDLE
) {
831 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
832 load
->inv_weight
= WMULT_IDLEPRIO
;
836 load
->weight
= scale_load(prio_to_weight
[prio
]);
837 load
->inv_weight
= prio_to_wmult
[prio
];
840 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
843 sched_info_queued(rq
, p
);
844 p
->sched_class
->enqueue_task(rq
, p
, flags
);
847 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
850 sched_info_dequeued(rq
, p
);
851 p
->sched_class
->dequeue_task(rq
, p
, flags
);
854 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
856 if (task_contributes_to_load(p
))
857 rq
->nr_uninterruptible
--;
859 enqueue_task(rq
, p
, flags
);
862 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
864 if (task_contributes_to_load(p
))
865 rq
->nr_uninterruptible
++;
867 dequeue_task(rq
, p
, flags
);
870 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
873 * In theory, the compile should just see 0 here, and optimize out the call
874 * to sched_rt_avg_update. But I don't trust it...
876 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
877 s64 steal
= 0, irq_delta
= 0;
879 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
880 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
883 * Since irq_time is only updated on {soft,}irq_exit, we might run into
884 * this case when a previous update_rq_clock() happened inside a
887 * When this happens, we stop ->clock_task and only update the
888 * prev_irq_time stamp to account for the part that fit, so that a next
889 * update will consume the rest. This ensures ->clock_task is
892 * It does however cause some slight miss-attribution of {soft,}irq
893 * time, a more accurate solution would be to update the irq_time using
894 * the current rq->clock timestamp, except that would require using
897 if (irq_delta
> delta
)
900 rq
->prev_irq_time
+= irq_delta
;
903 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
904 if (static_key_false((¶virt_steal_rq_enabled
))) {
905 steal
= paravirt_steal_clock(cpu_of(rq
));
906 steal
-= rq
->prev_steal_time_rq
;
908 if (unlikely(steal
> delta
))
911 rq
->prev_steal_time_rq
+= steal
;
916 rq
->clock_task
+= delta
;
918 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
919 if ((irq_delta
+ steal
) && sched_feat(NONTASK_CAPACITY
))
920 sched_rt_avg_update(rq
, irq_delta
+ steal
);
924 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
926 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
927 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
931 * Make it appear like a SCHED_FIFO task, its something
932 * userspace knows about and won't get confused about.
934 * Also, it will make PI more or less work without too
935 * much confusion -- but then, stop work should not
936 * rely on PI working anyway.
938 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
940 stop
->sched_class
= &stop_sched_class
;
943 cpu_rq(cpu
)->stop
= stop
;
947 * Reset it back to a normal scheduling class so that
948 * it can die in pieces.
950 old_stop
->sched_class
= &rt_sched_class
;
955 * __normal_prio - return the priority that is based on the static prio
957 static inline int __normal_prio(struct task_struct
*p
)
959 return p
->static_prio
;
963 * Calculate the expected normal priority: i.e. priority
964 * without taking RT-inheritance into account. Might be
965 * boosted by interactivity modifiers. Changes upon fork,
966 * setprio syscalls, and whenever the interactivity
967 * estimator recalculates.
969 static inline int normal_prio(struct task_struct
*p
)
973 if (task_has_dl_policy(p
))
974 prio
= MAX_DL_PRIO
-1;
975 else if (task_has_rt_policy(p
))
976 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
978 prio
= __normal_prio(p
);
983 * Calculate the current priority, i.e. the priority
984 * taken into account by the scheduler. This value might
985 * be boosted by RT tasks, or might be boosted by
986 * interactivity modifiers. Will be RT if the task got
987 * RT-boosted. If not then it returns p->normal_prio.
989 static int effective_prio(struct task_struct
*p
)
991 p
->normal_prio
= normal_prio(p
);
993 * If we are RT tasks or we were boosted to RT priority,
994 * keep the priority unchanged. Otherwise, update priority
995 * to the normal priority:
997 if (!rt_prio(p
->prio
))
998 return p
->normal_prio
;
1003 * task_curr - is this task currently executing on a CPU?
1004 * @p: the task in question.
1006 * Return: 1 if the task is currently executing. 0 otherwise.
1008 inline int task_curr(const struct task_struct
*p
)
1010 return cpu_curr(task_cpu(p
)) == p
;
1013 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1014 const struct sched_class
*prev_class
,
1017 if (prev_class
!= p
->sched_class
) {
1018 if (prev_class
->switched_from
)
1019 prev_class
->switched_from(rq
, p
);
1020 p
->sched_class
->switched_to(rq
, p
);
1021 } else if (oldprio
!= p
->prio
|| dl_task(p
))
1022 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
1025 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
1027 const struct sched_class
*class;
1029 if (p
->sched_class
== rq
->curr
->sched_class
) {
1030 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
1032 for_each_class(class) {
1033 if (class == rq
->curr
->sched_class
)
1035 if (class == p
->sched_class
) {
1043 * A queue event has occurred, and we're going to schedule. In
1044 * this case, we can save a useless back to back clock update.
1046 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
1047 rq
->skip_clock_update
= 1;
1051 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1053 #ifdef CONFIG_SCHED_DEBUG
1055 * We should never call set_task_cpu() on a blocked task,
1056 * ttwu() will sort out the placement.
1058 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
1059 !(task_preempt_count(p
) & PREEMPT_ACTIVE
));
1061 #ifdef CONFIG_LOCKDEP
1063 * The caller should hold either p->pi_lock or rq->lock, when changing
1064 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1066 * sched_move_task() holds both and thus holding either pins the cgroup,
1069 * Furthermore, all task_rq users should acquire both locks, see
1072 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1073 lockdep_is_held(&task_rq(p
)->lock
)));
1077 trace_sched_migrate_task(p
, new_cpu
);
1079 if (task_cpu(p
) != new_cpu
) {
1080 if (p
->sched_class
->migrate_task_rq
)
1081 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1082 p
->se
.nr_migrations
++;
1083 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1086 __set_task_cpu(p
, new_cpu
);
1089 static void __migrate_swap_task(struct task_struct
*p
, int cpu
)
1092 struct rq
*src_rq
, *dst_rq
;
1094 src_rq
= task_rq(p
);
1095 dst_rq
= cpu_rq(cpu
);
1097 deactivate_task(src_rq
, p
, 0);
1098 set_task_cpu(p
, cpu
);
1099 activate_task(dst_rq
, p
, 0);
1100 check_preempt_curr(dst_rq
, p
, 0);
1103 * Task isn't running anymore; make it appear like we migrated
1104 * it before it went to sleep. This means on wakeup we make the
1105 * previous cpu our targer instead of where it really is.
1111 struct migration_swap_arg
{
1112 struct task_struct
*src_task
, *dst_task
;
1113 int src_cpu
, dst_cpu
;
1116 static int migrate_swap_stop(void *data
)
1118 struct migration_swap_arg
*arg
= data
;
1119 struct rq
*src_rq
, *dst_rq
;
1122 src_rq
= cpu_rq(arg
->src_cpu
);
1123 dst_rq
= cpu_rq(arg
->dst_cpu
);
1125 double_raw_lock(&arg
->src_task
->pi_lock
,
1126 &arg
->dst_task
->pi_lock
);
1127 double_rq_lock(src_rq
, dst_rq
);
1128 if (task_cpu(arg
->dst_task
) != arg
->dst_cpu
)
1131 if (task_cpu(arg
->src_task
) != arg
->src_cpu
)
1134 if (!cpumask_test_cpu(arg
->dst_cpu
, tsk_cpus_allowed(arg
->src_task
)))
1137 if (!cpumask_test_cpu(arg
->src_cpu
, tsk_cpus_allowed(arg
->dst_task
)))
1140 __migrate_swap_task(arg
->src_task
, arg
->dst_cpu
);
1141 __migrate_swap_task(arg
->dst_task
, arg
->src_cpu
);
1146 double_rq_unlock(src_rq
, dst_rq
);
1147 raw_spin_unlock(&arg
->dst_task
->pi_lock
);
1148 raw_spin_unlock(&arg
->src_task
->pi_lock
);
1154 * Cross migrate two tasks
1156 int migrate_swap(struct task_struct
*cur
, struct task_struct
*p
)
1158 struct migration_swap_arg arg
;
1161 arg
= (struct migration_swap_arg
){
1163 .src_cpu
= task_cpu(cur
),
1165 .dst_cpu
= task_cpu(p
),
1168 if (arg
.src_cpu
== arg
.dst_cpu
)
1172 * These three tests are all lockless; this is OK since all of them
1173 * will be re-checked with proper locks held further down the line.
1175 if (!cpu_active(arg
.src_cpu
) || !cpu_active(arg
.dst_cpu
))
1178 if (!cpumask_test_cpu(arg
.dst_cpu
, tsk_cpus_allowed(arg
.src_task
)))
1181 if (!cpumask_test_cpu(arg
.src_cpu
, tsk_cpus_allowed(arg
.dst_task
)))
1184 trace_sched_swap_numa(cur
, arg
.src_cpu
, p
, arg
.dst_cpu
);
1185 ret
= stop_two_cpus(arg
.dst_cpu
, arg
.src_cpu
, migrate_swap_stop
, &arg
);
1191 struct migration_arg
{
1192 struct task_struct
*task
;
1196 static int migration_cpu_stop(void *data
);
1199 * wait_task_inactive - wait for a thread to unschedule.
1201 * If @match_state is nonzero, it's the @p->state value just checked and
1202 * not expected to change. If it changes, i.e. @p might have woken up,
1203 * then return zero. When we succeed in waiting for @p to be off its CPU,
1204 * we return a positive number (its total switch count). If a second call
1205 * a short while later returns the same number, the caller can be sure that
1206 * @p has remained unscheduled the whole time.
1208 * The caller must ensure that the task *will* unschedule sometime soon,
1209 * else this function might spin for a *long* time. This function can't
1210 * be called with interrupts off, or it may introduce deadlock with
1211 * smp_call_function() if an IPI is sent by the same process we are
1212 * waiting to become inactive.
1214 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1216 unsigned long flags
;
1223 * We do the initial early heuristics without holding
1224 * any task-queue locks at all. We'll only try to get
1225 * the runqueue lock when things look like they will
1231 * If the task is actively running on another CPU
1232 * still, just relax and busy-wait without holding
1235 * NOTE! Since we don't hold any locks, it's not
1236 * even sure that "rq" stays as the right runqueue!
1237 * But we don't care, since "task_running()" will
1238 * return false if the runqueue has changed and p
1239 * is actually now running somewhere else!
1241 while (task_running(rq
, p
)) {
1242 if (match_state
&& unlikely(p
->state
!= match_state
))
1248 * Ok, time to look more closely! We need the rq
1249 * lock now, to be *sure*. If we're wrong, we'll
1250 * just go back and repeat.
1252 rq
= task_rq_lock(p
, &flags
);
1253 trace_sched_wait_task(p
);
1254 running
= task_running(rq
, p
);
1257 if (!match_state
|| p
->state
== match_state
)
1258 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1259 task_rq_unlock(rq
, p
, &flags
);
1262 * If it changed from the expected state, bail out now.
1264 if (unlikely(!ncsw
))
1268 * Was it really running after all now that we
1269 * checked with the proper locks actually held?
1271 * Oops. Go back and try again..
1273 if (unlikely(running
)) {
1279 * It's not enough that it's not actively running,
1280 * it must be off the runqueue _entirely_, and not
1283 * So if it was still runnable (but just not actively
1284 * running right now), it's preempted, and we should
1285 * yield - it could be a while.
1287 if (unlikely(on_rq
)) {
1288 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1290 set_current_state(TASK_UNINTERRUPTIBLE
);
1291 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1296 * Ahh, all good. It wasn't running, and it wasn't
1297 * runnable, which means that it will never become
1298 * running in the future either. We're all done!
1307 * kick_process - kick a running thread to enter/exit the kernel
1308 * @p: the to-be-kicked thread
1310 * Cause a process which is running on another CPU to enter
1311 * kernel-mode, without any delay. (to get signals handled.)
1313 * NOTE: this function doesn't have to take the runqueue lock,
1314 * because all it wants to ensure is that the remote task enters
1315 * the kernel. If the IPI races and the task has been migrated
1316 * to another CPU then no harm is done and the purpose has been
1319 void kick_process(struct task_struct
*p
)
1325 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1326 smp_send_reschedule(cpu
);
1329 EXPORT_SYMBOL_GPL(kick_process
);
1330 #endif /* CONFIG_SMP */
1334 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1336 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1338 int nid
= cpu_to_node(cpu
);
1339 const struct cpumask
*nodemask
= NULL
;
1340 enum { cpuset
, possible
, fail
} state
= cpuset
;
1344 * If the node that the cpu is on has been offlined, cpu_to_node()
1345 * will return -1. There is no cpu on the node, and we should
1346 * select the cpu on the other node.
1349 nodemask
= cpumask_of_node(nid
);
1351 /* Look for allowed, online CPU in same node. */
1352 for_each_cpu(dest_cpu
, nodemask
) {
1353 if (!cpu_online(dest_cpu
))
1355 if (!cpu_active(dest_cpu
))
1357 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1363 /* Any allowed, online CPU? */
1364 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1365 if (!cpu_online(dest_cpu
))
1367 if (!cpu_active(dest_cpu
))
1374 /* No more Mr. Nice Guy. */
1375 cpuset_cpus_allowed_fallback(p
);
1380 do_set_cpus_allowed(p
, cpu_possible_mask
);
1391 if (state
!= cpuset
) {
1393 * Don't tell them about moving exiting tasks or
1394 * kernel threads (both mm NULL), since they never
1397 if (p
->mm
&& printk_ratelimit()) {
1398 printk_deferred("process %d (%s) no longer affine to cpu%d\n",
1399 task_pid_nr(p
), p
->comm
, cpu
);
1407 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1410 int select_task_rq(struct task_struct
*p
, int cpu
, int sd_flags
, int wake_flags
)
1412 cpu
= p
->sched_class
->select_task_rq(p
, cpu
, sd_flags
, wake_flags
);
1415 * In order not to call set_task_cpu() on a blocking task we need
1416 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1419 * Since this is common to all placement strategies, this lives here.
1421 * [ this allows ->select_task() to simply return task_cpu(p) and
1422 * not worry about this generic constraint ]
1424 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1426 cpu
= select_fallback_rq(task_cpu(p
), p
);
1431 static void update_avg(u64
*avg
, u64 sample
)
1433 s64 diff
= sample
- *avg
;
1439 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1441 #ifdef CONFIG_SCHEDSTATS
1442 struct rq
*rq
= this_rq();
1445 int this_cpu
= smp_processor_id();
1447 if (cpu
== this_cpu
) {
1448 schedstat_inc(rq
, ttwu_local
);
1449 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1451 struct sched_domain
*sd
;
1453 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1455 for_each_domain(this_cpu
, sd
) {
1456 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1457 schedstat_inc(sd
, ttwu_wake_remote
);
1464 if (wake_flags
& WF_MIGRATED
)
1465 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1467 #endif /* CONFIG_SMP */
1469 schedstat_inc(rq
, ttwu_count
);
1470 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1472 if (wake_flags
& WF_SYNC
)
1473 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1475 #endif /* CONFIG_SCHEDSTATS */
1478 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1480 activate_task(rq
, p
, en_flags
);
1483 /* if a worker is waking up, notify workqueue */
1484 if (p
->flags
& PF_WQ_WORKER
)
1485 wq_worker_waking_up(p
, cpu_of(rq
));
1489 * Mark the task runnable and perform wakeup-preemption.
1492 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1494 check_preempt_curr(rq
, p
, wake_flags
);
1495 trace_sched_wakeup(p
, true);
1497 p
->state
= TASK_RUNNING
;
1499 if (p
->sched_class
->task_woken
)
1500 p
->sched_class
->task_woken(rq
, p
);
1502 if (rq
->idle_stamp
) {
1503 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1504 u64 max
= 2*rq
->max_idle_balance_cost
;
1506 update_avg(&rq
->avg_idle
, delta
);
1508 if (rq
->avg_idle
> max
)
1517 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1520 if (p
->sched_contributes_to_load
)
1521 rq
->nr_uninterruptible
--;
1524 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1525 ttwu_do_wakeup(rq
, p
, wake_flags
);
1529 * Called in case the task @p isn't fully descheduled from its runqueue,
1530 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1531 * since all we need to do is flip p->state to TASK_RUNNING, since
1532 * the task is still ->on_rq.
1534 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1539 rq
= __task_rq_lock(p
);
1541 /* check_preempt_curr() may use rq clock */
1542 update_rq_clock(rq
);
1543 ttwu_do_wakeup(rq
, p
, wake_flags
);
1546 __task_rq_unlock(rq
);
1552 void sched_ttwu_pending(void)
1554 struct rq
*rq
= this_rq();
1555 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1556 struct task_struct
*p
;
1557 unsigned long flags
;
1562 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1565 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1566 llist
= llist_next(llist
);
1567 ttwu_do_activate(rq
, p
, 0);
1570 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1573 void scheduler_ipi(void)
1576 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1577 * TIF_NEED_RESCHED remotely (for the first time) will also send
1580 preempt_fold_need_resched();
1582 if (llist_empty(&this_rq()->wake_list
) && !got_nohz_idle_kick())
1586 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1587 * traditionally all their work was done from the interrupt return
1588 * path. Now that we actually do some work, we need to make sure
1591 * Some archs already do call them, luckily irq_enter/exit nest
1594 * Arguably we should visit all archs and update all handlers,
1595 * however a fair share of IPIs are still resched only so this would
1596 * somewhat pessimize the simple resched case.
1599 sched_ttwu_pending();
1602 * Check if someone kicked us for doing the nohz idle load balance.
1604 if (unlikely(got_nohz_idle_kick())) {
1605 this_rq()->idle_balance
= 1;
1606 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1611 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1613 struct rq
*rq
= cpu_rq(cpu
);
1615 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
)) {
1616 if (!set_nr_if_polling(rq
->idle
))
1617 smp_send_reschedule(cpu
);
1619 trace_sched_wake_idle_without_ipi(cpu
);
1623 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1625 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1627 #endif /* CONFIG_SMP */
1629 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1631 struct rq
*rq
= cpu_rq(cpu
);
1633 #if defined(CONFIG_SMP)
1634 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1635 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1636 ttwu_queue_remote(p
, cpu
);
1641 raw_spin_lock(&rq
->lock
);
1642 ttwu_do_activate(rq
, p
, 0);
1643 raw_spin_unlock(&rq
->lock
);
1647 * try_to_wake_up - wake up a thread
1648 * @p: the thread to be awakened
1649 * @state: the mask of task states that can be woken
1650 * @wake_flags: wake modifier flags (WF_*)
1652 * Put it on the run-queue if it's not already there. The "current"
1653 * thread is always on the run-queue (except when the actual
1654 * re-schedule is in progress), and as such you're allowed to do
1655 * the simpler "current->state = TASK_RUNNING" to mark yourself
1656 * runnable without the overhead of this.
1658 * Return: %true if @p was woken up, %false if it was already running.
1659 * or @state didn't match @p's state.
1662 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1664 unsigned long flags
;
1665 int cpu
, success
= 0;
1668 * If we are going to wake up a thread waiting for CONDITION we
1669 * need to ensure that CONDITION=1 done by the caller can not be
1670 * reordered with p->state check below. This pairs with mb() in
1671 * set_current_state() the waiting thread does.
1673 smp_mb__before_spinlock();
1674 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1675 if (!(p
->state
& state
))
1678 success
= 1; /* we're going to change ->state */
1681 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1686 * If the owning (remote) cpu is still in the middle of schedule() with
1687 * this task as prev, wait until its done referencing the task.
1692 * Pairs with the smp_wmb() in finish_lock_switch().
1696 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1697 p
->state
= TASK_WAKING
;
1699 if (p
->sched_class
->task_waking
)
1700 p
->sched_class
->task_waking(p
);
1702 cpu
= select_task_rq(p
, p
->wake_cpu
, SD_BALANCE_WAKE
, wake_flags
);
1703 if (task_cpu(p
) != cpu
) {
1704 wake_flags
|= WF_MIGRATED
;
1705 set_task_cpu(p
, cpu
);
1707 #endif /* CONFIG_SMP */
1711 ttwu_stat(p
, cpu
, wake_flags
);
1713 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1719 * try_to_wake_up_local - try to wake up a local task with rq lock held
1720 * @p: the thread to be awakened
1722 * Put @p on the run-queue if it's not already there. The caller must
1723 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1726 static void try_to_wake_up_local(struct task_struct
*p
)
1728 struct rq
*rq
= task_rq(p
);
1730 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1731 WARN_ON_ONCE(p
== current
))
1734 lockdep_assert_held(&rq
->lock
);
1736 if (!raw_spin_trylock(&p
->pi_lock
)) {
1737 raw_spin_unlock(&rq
->lock
);
1738 raw_spin_lock(&p
->pi_lock
);
1739 raw_spin_lock(&rq
->lock
);
1742 if (!(p
->state
& TASK_NORMAL
))
1746 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1748 ttwu_do_wakeup(rq
, p
, 0);
1749 ttwu_stat(p
, smp_processor_id(), 0);
1751 raw_spin_unlock(&p
->pi_lock
);
1755 * wake_up_process - Wake up a specific process
1756 * @p: The process to be woken up.
1758 * Attempt to wake up the nominated process and move it to the set of runnable
1761 * Return: 1 if the process was woken up, 0 if it was already running.
1763 * It may be assumed that this function implies a write memory barrier before
1764 * changing the task state if and only if any tasks are woken up.
1766 int wake_up_process(struct task_struct
*p
)
1768 WARN_ON(task_is_stopped_or_traced(p
));
1769 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1771 EXPORT_SYMBOL(wake_up_process
);
1773 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1775 return try_to_wake_up(p
, state
, 0);
1779 * Perform scheduler related setup for a newly forked process p.
1780 * p is forked by current.
1782 * __sched_fork() is basic setup used by init_idle() too:
1784 static void __sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1789 p
->se
.exec_start
= 0;
1790 p
->se
.sum_exec_runtime
= 0;
1791 p
->se
.prev_sum_exec_runtime
= 0;
1792 p
->se
.nr_migrations
= 0;
1794 INIT_LIST_HEAD(&p
->se
.group_node
);
1796 #ifdef CONFIG_SCHEDSTATS
1797 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1800 RB_CLEAR_NODE(&p
->dl
.rb_node
);
1801 hrtimer_init(&p
->dl
.dl_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1802 p
->dl
.dl_runtime
= p
->dl
.runtime
= 0;
1803 p
->dl
.dl_deadline
= p
->dl
.deadline
= 0;
1804 p
->dl
.dl_period
= 0;
1807 INIT_LIST_HEAD(&p
->rt
.run_list
);
1809 #ifdef CONFIG_PREEMPT_NOTIFIERS
1810 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1813 #ifdef CONFIG_NUMA_BALANCING
1814 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1815 p
->mm
->numa_next_scan
= jiffies
+ msecs_to_jiffies(sysctl_numa_balancing_scan_delay
);
1816 p
->mm
->numa_scan_seq
= 0;
1819 if (clone_flags
& CLONE_VM
)
1820 p
->numa_preferred_nid
= current
->numa_preferred_nid
;
1822 p
->numa_preferred_nid
= -1;
1824 p
->node_stamp
= 0ULL;
1825 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1826 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1827 p
->numa_work
.next
= &p
->numa_work
;
1828 p
->numa_faults_memory
= NULL
;
1829 p
->numa_faults_buffer_memory
= NULL
;
1830 p
->last_task_numa_placement
= 0;
1831 p
->last_sum_exec_runtime
= 0;
1833 INIT_LIST_HEAD(&p
->numa_entry
);
1834 p
->numa_group
= NULL
;
1835 #endif /* CONFIG_NUMA_BALANCING */
1838 #ifdef CONFIG_NUMA_BALANCING
1839 #ifdef CONFIG_SCHED_DEBUG
1840 void set_numabalancing_state(bool enabled
)
1843 sched_feat_set("NUMA");
1845 sched_feat_set("NO_NUMA");
1848 __read_mostly
bool numabalancing_enabled
;
1850 void set_numabalancing_state(bool enabled
)
1852 numabalancing_enabled
= enabled
;
1854 #endif /* CONFIG_SCHED_DEBUG */
1856 #ifdef CONFIG_PROC_SYSCTL
1857 int sysctl_numa_balancing(struct ctl_table
*table
, int write
,
1858 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1862 int state
= numabalancing_enabled
;
1864 if (write
&& !capable(CAP_SYS_ADMIN
))
1869 err
= proc_dointvec_minmax(&t
, write
, buffer
, lenp
, ppos
);
1873 set_numabalancing_state(state
);
1880 * fork()/clone()-time setup:
1882 int sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1884 unsigned long flags
;
1885 int cpu
= get_cpu();
1887 __sched_fork(clone_flags
, p
);
1889 * We mark the process as running here. This guarantees that
1890 * nobody will actually run it, and a signal or other external
1891 * event cannot wake it up and insert it on the runqueue either.
1893 p
->state
= TASK_RUNNING
;
1896 * Make sure we do not leak PI boosting priority to the child.
1898 p
->prio
= current
->normal_prio
;
1901 * Revert to default priority/policy on fork if requested.
1903 if (unlikely(p
->sched_reset_on_fork
)) {
1904 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
1905 p
->policy
= SCHED_NORMAL
;
1906 p
->static_prio
= NICE_TO_PRIO(0);
1908 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1909 p
->static_prio
= NICE_TO_PRIO(0);
1911 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1915 * We don't need the reset flag anymore after the fork. It has
1916 * fulfilled its duty:
1918 p
->sched_reset_on_fork
= 0;
1921 if (dl_prio(p
->prio
)) {
1924 } else if (rt_prio(p
->prio
)) {
1925 p
->sched_class
= &rt_sched_class
;
1927 p
->sched_class
= &fair_sched_class
;
1930 if (p
->sched_class
->task_fork
)
1931 p
->sched_class
->task_fork(p
);
1934 * The child is not yet in the pid-hash so no cgroup attach races,
1935 * and the cgroup is pinned to this child due to cgroup_fork()
1936 * is ran before sched_fork().
1938 * Silence PROVE_RCU.
1940 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1941 set_task_cpu(p
, cpu
);
1942 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1944 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1945 if (likely(sched_info_on()))
1946 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1948 #if defined(CONFIG_SMP)
1951 init_task_preempt_count(p
);
1953 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1954 RB_CLEAR_NODE(&p
->pushable_dl_tasks
);
1961 unsigned long to_ratio(u64 period
, u64 runtime
)
1963 if (runtime
== RUNTIME_INF
)
1967 * Doing this here saves a lot of checks in all
1968 * the calling paths, and returning zero seems
1969 * safe for them anyway.
1974 return div64_u64(runtime
<< 20, period
);
1978 inline struct dl_bw
*dl_bw_of(int i
)
1980 return &cpu_rq(i
)->rd
->dl_bw
;
1983 static inline int dl_bw_cpus(int i
)
1985 struct root_domain
*rd
= cpu_rq(i
)->rd
;
1988 for_each_cpu_and(i
, rd
->span
, cpu_active_mask
)
1994 inline struct dl_bw
*dl_bw_of(int i
)
1996 return &cpu_rq(i
)->dl
.dl_bw
;
1999 static inline int dl_bw_cpus(int i
)
2006 void __dl_clear(struct dl_bw
*dl_b
, u64 tsk_bw
)
2008 dl_b
->total_bw
-= tsk_bw
;
2012 void __dl_add(struct dl_bw
*dl_b
, u64 tsk_bw
)
2014 dl_b
->total_bw
+= tsk_bw
;
2018 bool __dl_overflow(struct dl_bw
*dl_b
, int cpus
, u64 old_bw
, u64 new_bw
)
2020 return dl_b
->bw
!= -1 &&
2021 dl_b
->bw
* cpus
< dl_b
->total_bw
- old_bw
+ new_bw
;
2025 * We must be sure that accepting a new task (or allowing changing the
2026 * parameters of an existing one) is consistent with the bandwidth
2027 * constraints. If yes, this function also accordingly updates the currently
2028 * allocated bandwidth to reflect the new situation.
2030 * This function is called while holding p's rq->lock.
2032 static int dl_overflow(struct task_struct
*p
, int policy
,
2033 const struct sched_attr
*attr
)
2036 struct dl_bw
*dl_b
= dl_bw_of(task_cpu(p
));
2037 u64 period
= attr
->sched_period
?: attr
->sched_deadline
;
2038 u64 runtime
= attr
->sched_runtime
;
2039 u64 new_bw
= dl_policy(policy
) ? to_ratio(period
, runtime
) : 0;
2042 if (new_bw
== p
->dl
.dl_bw
)
2046 * Either if a task, enters, leave, or stays -deadline but changes
2047 * its parameters, we may need to update accordingly the total
2048 * allocated bandwidth of the container.
2050 raw_spin_lock(&dl_b
->lock
);
2051 cpus
= dl_bw_cpus(task_cpu(p
));
2052 if (dl_policy(policy
) && !task_has_dl_policy(p
) &&
2053 !__dl_overflow(dl_b
, cpus
, 0, new_bw
)) {
2054 __dl_add(dl_b
, new_bw
);
2056 } else if (dl_policy(policy
) && task_has_dl_policy(p
) &&
2057 !__dl_overflow(dl_b
, cpus
, p
->dl
.dl_bw
, new_bw
)) {
2058 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2059 __dl_add(dl_b
, new_bw
);
2061 } else if (!dl_policy(policy
) && task_has_dl_policy(p
)) {
2062 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2065 raw_spin_unlock(&dl_b
->lock
);
2070 extern void init_dl_bw(struct dl_bw
*dl_b
);
2073 * wake_up_new_task - wake up a newly created task for the first time.
2075 * This function will do some initial scheduler statistics housekeeping
2076 * that must be done for every newly created context, then puts the task
2077 * on the runqueue and wakes it.
2079 void wake_up_new_task(struct task_struct
*p
)
2081 unsigned long flags
;
2084 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2087 * Fork balancing, do it here and not earlier because:
2088 * - cpus_allowed can change in the fork path
2089 * - any previously selected cpu might disappear through hotplug
2091 set_task_cpu(p
, select_task_rq(p
, task_cpu(p
), SD_BALANCE_FORK
, 0));
2094 /* Initialize new task's runnable average */
2095 init_task_runnable_average(p
);
2096 rq
= __task_rq_lock(p
);
2097 activate_task(rq
, p
, 0);
2099 trace_sched_wakeup_new(p
, true);
2100 check_preempt_curr(rq
, p
, WF_FORK
);
2102 if (p
->sched_class
->task_woken
)
2103 p
->sched_class
->task_woken(rq
, p
);
2105 task_rq_unlock(rq
, p
, &flags
);
2108 #ifdef CONFIG_PREEMPT_NOTIFIERS
2111 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2112 * @notifier: notifier struct to register
2114 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2116 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2118 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2121 * preempt_notifier_unregister - no longer interested in preemption notifications
2122 * @notifier: notifier struct to unregister
2124 * This is safe to call from within a preemption notifier.
2126 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2128 hlist_del(¬ifier
->link
);
2130 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2132 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2134 struct preempt_notifier
*notifier
;
2136 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2137 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2141 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2142 struct task_struct
*next
)
2144 struct preempt_notifier
*notifier
;
2146 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2147 notifier
->ops
->sched_out(notifier
, next
);
2150 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2152 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2157 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2158 struct task_struct
*next
)
2162 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2165 * prepare_task_switch - prepare to switch tasks
2166 * @rq: the runqueue preparing to switch
2167 * @prev: the current task that is being switched out
2168 * @next: the task we are going to switch to.
2170 * This is called with the rq lock held and interrupts off. It must
2171 * be paired with a subsequent finish_task_switch after the context
2174 * prepare_task_switch sets up locking and calls architecture specific
2178 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2179 struct task_struct
*next
)
2181 trace_sched_switch(prev
, next
);
2182 sched_info_switch(rq
, prev
, next
);
2183 perf_event_task_sched_out(prev
, next
);
2184 fire_sched_out_preempt_notifiers(prev
, next
);
2185 prepare_lock_switch(rq
, next
);
2186 prepare_arch_switch(next
);
2190 * finish_task_switch - clean up after a task-switch
2191 * @rq: runqueue associated with task-switch
2192 * @prev: the thread we just switched away from.
2194 * finish_task_switch must be called after the context switch, paired
2195 * with a prepare_task_switch call before the context switch.
2196 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2197 * and do any other architecture-specific cleanup actions.
2199 * Note that we may have delayed dropping an mm in context_switch(). If
2200 * so, we finish that here outside of the runqueue lock. (Doing it
2201 * with the lock held can cause deadlocks; see schedule() for
2204 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2205 __releases(rq
->lock
)
2207 struct mm_struct
*mm
= rq
->prev_mm
;
2213 * A task struct has one reference for the use as "current".
2214 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2215 * schedule one last time. The schedule call will never return, and
2216 * the scheduled task must drop that reference.
2217 * The test for TASK_DEAD must occur while the runqueue locks are
2218 * still held, otherwise prev could be scheduled on another cpu, die
2219 * there before we look at prev->state, and then the reference would
2221 * Manfred Spraul <manfred@colorfullife.com>
2223 prev_state
= prev
->state
;
2224 vtime_task_switch(prev
);
2225 finish_arch_switch(prev
);
2226 perf_event_task_sched_in(prev
, current
);
2227 finish_lock_switch(rq
, prev
);
2228 finish_arch_post_lock_switch();
2230 fire_sched_in_preempt_notifiers(current
);
2233 if (unlikely(prev_state
== TASK_DEAD
)) {
2234 if (prev
->sched_class
->task_dead
)
2235 prev
->sched_class
->task_dead(prev
);
2238 * Remove function-return probe instances associated with this
2239 * task and put them back on the free list.
2241 kprobe_flush_task(prev
);
2242 put_task_struct(prev
);
2245 tick_nohz_task_switch(current
);
2250 /* rq->lock is NOT held, but preemption is disabled */
2251 static inline void post_schedule(struct rq
*rq
)
2253 if (rq
->post_schedule
) {
2254 unsigned long flags
;
2256 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2257 if (rq
->curr
->sched_class
->post_schedule
)
2258 rq
->curr
->sched_class
->post_schedule(rq
);
2259 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2261 rq
->post_schedule
= 0;
2267 static inline void post_schedule(struct rq
*rq
)
2274 * schedule_tail - first thing a freshly forked thread must call.
2275 * @prev: the thread we just switched away from.
2277 asmlinkage __visible
void schedule_tail(struct task_struct
*prev
)
2278 __releases(rq
->lock
)
2280 struct rq
*rq
= this_rq();
2282 finish_task_switch(rq
, prev
);
2285 * FIXME: do we need to worry about rq being invalidated by the
2290 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2291 /* In this case, finish_task_switch does not reenable preemption */
2294 if (current
->set_child_tid
)
2295 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2299 * context_switch - switch to the new MM and the new
2300 * thread's register state.
2303 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2304 struct task_struct
*next
)
2306 struct mm_struct
*mm
, *oldmm
;
2308 prepare_task_switch(rq
, prev
, next
);
2311 oldmm
= prev
->active_mm
;
2313 * For paravirt, this is coupled with an exit in switch_to to
2314 * combine the page table reload and the switch backend into
2317 arch_start_context_switch(prev
);
2320 next
->active_mm
= oldmm
;
2321 atomic_inc(&oldmm
->mm_count
);
2322 enter_lazy_tlb(oldmm
, next
);
2324 switch_mm(oldmm
, mm
, next
);
2327 prev
->active_mm
= NULL
;
2328 rq
->prev_mm
= oldmm
;
2331 * Since the runqueue lock will be released by the next
2332 * task (which is an invalid locking op but in the case
2333 * of the scheduler it's an obvious special-case), so we
2334 * do an early lockdep release here:
2336 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2337 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2340 context_tracking_task_switch(prev
, next
);
2341 /* Here we just switch the register state and the stack. */
2342 switch_to(prev
, next
, prev
);
2346 * this_rq must be evaluated again because prev may have moved
2347 * CPUs since it called schedule(), thus the 'rq' on its stack
2348 * frame will be invalid.
2350 finish_task_switch(this_rq(), prev
);
2354 * nr_running and nr_context_switches:
2356 * externally visible scheduler statistics: current number of runnable
2357 * threads, total number of context switches performed since bootup.
2359 unsigned long nr_running(void)
2361 unsigned long i
, sum
= 0;
2363 for_each_online_cpu(i
)
2364 sum
+= cpu_rq(i
)->nr_running
;
2370 * Check if only the current task is running on the cpu.
2372 bool single_task_running(void)
2374 if (cpu_rq(smp_processor_id())->nr_running
== 1)
2379 EXPORT_SYMBOL(single_task_running
);
2381 unsigned long long nr_context_switches(void)
2384 unsigned long long sum
= 0;
2386 for_each_possible_cpu(i
)
2387 sum
+= cpu_rq(i
)->nr_switches
;
2392 unsigned long nr_iowait(void)
2394 unsigned long i
, sum
= 0;
2396 for_each_possible_cpu(i
)
2397 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2402 unsigned long nr_iowait_cpu(int cpu
)
2404 struct rq
*this = cpu_rq(cpu
);
2405 return atomic_read(&this->nr_iowait
);
2408 void get_iowait_load(unsigned long *nr_waiters
, unsigned long *load
)
2410 struct rq
*this = this_rq();
2411 *nr_waiters
= atomic_read(&this->nr_iowait
);
2412 *load
= this->cpu_load
[0];
2418 * sched_exec - execve() is a valuable balancing opportunity, because at
2419 * this point the task has the smallest effective memory and cache footprint.
2421 void sched_exec(void)
2423 struct task_struct
*p
= current
;
2424 unsigned long flags
;
2427 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2428 dest_cpu
= p
->sched_class
->select_task_rq(p
, task_cpu(p
), SD_BALANCE_EXEC
, 0);
2429 if (dest_cpu
== smp_processor_id())
2432 if (likely(cpu_active(dest_cpu
))) {
2433 struct migration_arg arg
= { p
, dest_cpu
};
2435 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2436 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2440 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2445 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2446 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2448 EXPORT_PER_CPU_SYMBOL(kstat
);
2449 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2452 * Return any ns on the sched_clock that have not yet been accounted in
2453 * @p in case that task is currently running.
2455 * Called with task_rq_lock() held on @rq.
2457 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2462 * Must be ->curr _and_ ->on_rq. If dequeued, we would
2463 * project cycles that may never be accounted to this
2464 * thread, breaking clock_gettime().
2466 if (task_current(rq
, p
) && p
->on_rq
) {
2467 update_rq_clock(rq
);
2468 ns
= rq_clock_task(rq
) - p
->se
.exec_start
;
2476 unsigned long long task_delta_exec(struct task_struct
*p
)
2478 unsigned long flags
;
2482 rq
= task_rq_lock(p
, &flags
);
2483 ns
= do_task_delta_exec(p
, rq
);
2484 task_rq_unlock(rq
, p
, &flags
);
2490 * Return accounted runtime for the task.
2491 * In case the task is currently running, return the runtime plus current's
2492 * pending runtime that have not been accounted yet.
2494 unsigned long long task_sched_runtime(struct task_struct
*p
)
2496 unsigned long flags
;
2500 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2502 * 64-bit doesn't need locks to atomically read a 64bit value.
2503 * So we have a optimization chance when the task's delta_exec is 0.
2504 * Reading ->on_cpu is racy, but this is ok.
2506 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2507 * If we race with it entering cpu, unaccounted time is 0. This is
2508 * indistinguishable from the read occurring a few cycles earlier.
2509 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
2510 * been accounted, so we're correct here as well.
2512 if (!p
->on_cpu
|| !p
->on_rq
)
2513 return p
->se
.sum_exec_runtime
;
2516 rq
= task_rq_lock(p
, &flags
);
2517 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2518 task_rq_unlock(rq
, p
, &flags
);
2524 * This function gets called by the timer code, with HZ frequency.
2525 * We call it with interrupts disabled.
2527 void scheduler_tick(void)
2529 int cpu
= smp_processor_id();
2530 struct rq
*rq
= cpu_rq(cpu
);
2531 struct task_struct
*curr
= rq
->curr
;
2535 raw_spin_lock(&rq
->lock
);
2536 update_rq_clock(rq
);
2537 curr
->sched_class
->task_tick(rq
, curr
, 0);
2538 update_cpu_load_active(rq
);
2539 raw_spin_unlock(&rq
->lock
);
2541 perf_event_task_tick();
2544 rq
->idle_balance
= idle_cpu(cpu
);
2545 trigger_load_balance(rq
);
2547 rq_last_tick_reset(rq
);
2550 #ifdef CONFIG_NO_HZ_FULL
2552 * scheduler_tick_max_deferment
2554 * Keep at least one tick per second when a single
2555 * active task is running because the scheduler doesn't
2556 * yet completely support full dynticks environment.
2558 * This makes sure that uptime, CFS vruntime, load
2559 * balancing, etc... continue to move forward, even
2560 * with a very low granularity.
2562 * Return: Maximum deferment in nanoseconds.
2564 u64
scheduler_tick_max_deferment(void)
2566 struct rq
*rq
= this_rq();
2567 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2569 next
= rq
->last_sched_tick
+ HZ
;
2571 if (time_before_eq(next
, now
))
2574 return jiffies_to_nsecs(next
- now
);
2578 notrace
unsigned long get_parent_ip(unsigned long addr
)
2580 if (in_lock_functions(addr
)) {
2581 addr
= CALLER_ADDR2
;
2582 if (in_lock_functions(addr
))
2583 addr
= CALLER_ADDR3
;
2588 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2589 defined(CONFIG_PREEMPT_TRACER))
2591 void preempt_count_add(int val
)
2593 #ifdef CONFIG_DEBUG_PREEMPT
2597 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2600 __preempt_count_add(val
);
2601 #ifdef CONFIG_DEBUG_PREEMPT
2603 * Spinlock count overflowing soon?
2605 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2608 if (preempt_count() == val
) {
2609 unsigned long ip
= get_parent_ip(CALLER_ADDR1
);
2610 #ifdef CONFIG_DEBUG_PREEMPT
2611 current
->preempt_disable_ip
= ip
;
2613 trace_preempt_off(CALLER_ADDR0
, ip
);
2616 EXPORT_SYMBOL(preempt_count_add
);
2617 NOKPROBE_SYMBOL(preempt_count_add
);
2619 void preempt_count_sub(int val
)
2621 #ifdef CONFIG_DEBUG_PREEMPT
2625 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2628 * Is the spinlock portion underflowing?
2630 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2631 !(preempt_count() & PREEMPT_MASK
)))
2635 if (preempt_count() == val
)
2636 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2637 __preempt_count_sub(val
);
2639 EXPORT_SYMBOL(preempt_count_sub
);
2640 NOKPROBE_SYMBOL(preempt_count_sub
);
2645 * Print scheduling while atomic bug:
2647 static noinline
void __schedule_bug(struct task_struct
*prev
)
2649 if (oops_in_progress
)
2652 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2653 prev
->comm
, prev
->pid
, preempt_count());
2655 debug_show_held_locks(prev
);
2657 if (irqs_disabled())
2658 print_irqtrace_events(prev
);
2659 #ifdef CONFIG_DEBUG_PREEMPT
2660 if (in_atomic_preempt_off()) {
2661 pr_err("Preemption disabled at:");
2662 print_ip_sym(current
->preempt_disable_ip
);
2667 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2671 * Various schedule()-time debugging checks and statistics:
2673 static inline void schedule_debug(struct task_struct
*prev
)
2676 * Test if we are atomic. Since do_exit() needs to call into
2677 * schedule() atomically, we ignore that path. Otherwise whine
2678 * if we are scheduling when we should not.
2680 if (unlikely(in_atomic_preempt_off() && prev
->state
!= TASK_DEAD
))
2681 __schedule_bug(prev
);
2684 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2686 schedstat_inc(this_rq(), sched_count
);
2690 * Pick up the highest-prio task:
2692 static inline struct task_struct
*
2693 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
2695 const struct sched_class
*class = &fair_sched_class
;
2696 struct task_struct
*p
;
2699 * Optimization: we know that if all tasks are in
2700 * the fair class we can call that function directly:
2702 if (likely(prev
->sched_class
== class &&
2703 rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2704 p
= fair_sched_class
.pick_next_task(rq
, prev
);
2705 if (unlikely(p
== RETRY_TASK
))
2708 /* assumes fair_sched_class->next == idle_sched_class */
2710 p
= idle_sched_class
.pick_next_task(rq
, prev
);
2716 for_each_class(class) {
2717 p
= class->pick_next_task(rq
, prev
);
2719 if (unlikely(p
== RETRY_TASK
))
2725 BUG(); /* the idle class will always have a runnable task */
2729 * __schedule() is the main scheduler function.
2731 * The main means of driving the scheduler and thus entering this function are:
2733 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2735 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2736 * paths. For example, see arch/x86/entry_64.S.
2738 * To drive preemption between tasks, the scheduler sets the flag in timer
2739 * interrupt handler scheduler_tick().
2741 * 3. Wakeups don't really cause entry into schedule(). They add a
2742 * task to the run-queue and that's it.
2744 * Now, if the new task added to the run-queue preempts the current
2745 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2746 * called on the nearest possible occasion:
2748 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2750 * - in syscall or exception context, at the next outmost
2751 * preempt_enable(). (this might be as soon as the wake_up()'s
2754 * - in IRQ context, return from interrupt-handler to
2755 * preemptible context
2757 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2760 * - cond_resched() call
2761 * - explicit schedule() call
2762 * - return from syscall or exception to user-space
2763 * - return from interrupt-handler to user-space
2765 static void __sched
__schedule(void)
2767 struct task_struct
*prev
, *next
;
2768 unsigned long *switch_count
;
2774 cpu
= smp_processor_id();
2776 rcu_note_context_switch(cpu
);
2779 schedule_debug(prev
);
2781 if (sched_feat(HRTICK
))
2785 * Make sure that signal_pending_state()->signal_pending() below
2786 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2787 * done by the caller to avoid the race with signal_wake_up().
2789 smp_mb__before_spinlock();
2790 raw_spin_lock_irq(&rq
->lock
);
2792 switch_count
= &prev
->nivcsw
;
2793 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2794 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2795 prev
->state
= TASK_RUNNING
;
2797 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2801 * If a worker went to sleep, notify and ask workqueue
2802 * whether it wants to wake up a task to maintain
2805 if (prev
->flags
& PF_WQ_WORKER
) {
2806 struct task_struct
*to_wakeup
;
2808 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2810 try_to_wake_up_local(to_wakeup
);
2813 switch_count
= &prev
->nvcsw
;
2816 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
2817 update_rq_clock(rq
);
2819 next
= pick_next_task(rq
, prev
);
2820 clear_tsk_need_resched(prev
);
2821 clear_preempt_need_resched();
2822 rq
->skip_clock_update
= 0;
2824 if (likely(prev
!= next
)) {
2829 context_switch(rq
, prev
, next
); /* unlocks the rq */
2831 * The context switch have flipped the stack from under us
2832 * and restored the local variables which were saved when
2833 * this task called schedule() in the past. prev == current
2834 * is still correct, but it can be moved to another cpu/rq.
2836 cpu
= smp_processor_id();
2839 raw_spin_unlock_irq(&rq
->lock
);
2843 sched_preempt_enable_no_resched();
2848 static inline void sched_submit_work(struct task_struct
*tsk
)
2850 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2853 * If we are going to sleep and we have plugged IO queued,
2854 * make sure to submit it to avoid deadlocks.
2856 if (blk_needs_flush_plug(tsk
))
2857 blk_schedule_flush_plug(tsk
);
2860 asmlinkage __visible
void __sched
schedule(void)
2862 struct task_struct
*tsk
= current
;
2864 sched_submit_work(tsk
);
2867 EXPORT_SYMBOL(schedule
);
2869 #ifdef CONFIG_CONTEXT_TRACKING
2870 asmlinkage __visible
void __sched
schedule_user(void)
2873 * If we come here after a random call to set_need_resched(),
2874 * or we have been woken up remotely but the IPI has not yet arrived,
2875 * we haven't yet exited the RCU idle mode. Do it here manually until
2876 * we find a better solution.
2885 * schedule_preempt_disabled - called with preemption disabled
2887 * Returns with preemption disabled. Note: preempt_count must be 1
2889 void __sched
schedule_preempt_disabled(void)
2891 sched_preempt_enable_no_resched();
2896 #ifdef CONFIG_PREEMPT
2898 * this is the entry point to schedule() from in-kernel preemption
2899 * off of preempt_enable. Kernel preemptions off return from interrupt
2900 * occur there and call schedule directly.
2902 asmlinkage __visible
void __sched notrace
preempt_schedule(void)
2905 * If there is a non-zero preempt_count or interrupts are disabled,
2906 * we do not want to preempt the current task. Just return..
2908 if (likely(!preemptible()))
2912 __preempt_count_add(PREEMPT_ACTIVE
);
2914 __preempt_count_sub(PREEMPT_ACTIVE
);
2917 * Check again in case we missed a preemption opportunity
2918 * between schedule and now.
2921 } while (need_resched());
2923 NOKPROBE_SYMBOL(preempt_schedule
);
2924 EXPORT_SYMBOL(preempt_schedule
);
2925 #endif /* CONFIG_PREEMPT */
2928 * this is the entry point to schedule() from kernel preemption
2929 * off of irq context.
2930 * Note, that this is called and return with irqs disabled. This will
2931 * protect us against recursive calling from irq.
2933 asmlinkage __visible
void __sched
preempt_schedule_irq(void)
2935 enum ctx_state prev_state
;
2937 /* Catch callers which need to be fixed */
2938 BUG_ON(preempt_count() || !irqs_disabled());
2940 prev_state
= exception_enter();
2943 __preempt_count_add(PREEMPT_ACTIVE
);
2946 local_irq_disable();
2947 __preempt_count_sub(PREEMPT_ACTIVE
);
2950 * Check again in case we missed a preemption opportunity
2951 * between schedule and now.
2954 } while (need_resched());
2956 exception_exit(prev_state
);
2959 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2962 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2964 EXPORT_SYMBOL(default_wake_function
);
2966 #ifdef CONFIG_RT_MUTEXES
2969 * rt_mutex_setprio - set the current priority of a task
2971 * @prio: prio value (kernel-internal form)
2973 * This function changes the 'effective' priority of a task. It does
2974 * not touch ->normal_prio like __setscheduler().
2976 * Used by the rt_mutex code to implement priority inheritance
2977 * logic. Call site only calls if the priority of the task changed.
2979 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
2981 int oldprio
, on_rq
, running
, enqueue_flag
= 0;
2983 const struct sched_class
*prev_class
;
2985 BUG_ON(prio
> MAX_PRIO
);
2987 rq
= __task_rq_lock(p
);
2990 * Idle task boosting is a nono in general. There is one
2991 * exception, when PREEMPT_RT and NOHZ is active:
2993 * The idle task calls get_next_timer_interrupt() and holds
2994 * the timer wheel base->lock on the CPU and another CPU wants
2995 * to access the timer (probably to cancel it). We can safely
2996 * ignore the boosting request, as the idle CPU runs this code
2997 * with interrupts disabled and will complete the lock
2998 * protected section without being interrupted. So there is no
2999 * real need to boost.
3001 if (unlikely(p
== rq
->idle
)) {
3002 WARN_ON(p
!= rq
->curr
);
3003 WARN_ON(p
->pi_blocked_on
);
3007 trace_sched_pi_setprio(p
, prio
);
3009 prev_class
= p
->sched_class
;
3011 running
= task_current(rq
, p
);
3013 dequeue_task(rq
, p
, 0);
3015 p
->sched_class
->put_prev_task(rq
, p
);
3018 * Boosting condition are:
3019 * 1. -rt task is running and holds mutex A
3020 * --> -dl task blocks on mutex A
3022 * 2. -dl task is running and holds mutex A
3023 * --> -dl task blocks on mutex A and could preempt the
3026 if (dl_prio(prio
)) {
3027 struct task_struct
*pi_task
= rt_mutex_get_top_task(p
);
3028 if (!dl_prio(p
->normal_prio
) ||
3029 (pi_task
&& dl_entity_preempt(&pi_task
->dl
, &p
->dl
))) {
3030 p
->dl
.dl_boosted
= 1;
3031 p
->dl
.dl_throttled
= 0;
3032 enqueue_flag
= ENQUEUE_REPLENISH
;
3034 p
->dl
.dl_boosted
= 0;
3035 p
->sched_class
= &dl_sched_class
;
3036 } else if (rt_prio(prio
)) {
3037 if (dl_prio(oldprio
))
3038 p
->dl
.dl_boosted
= 0;
3040 enqueue_flag
= ENQUEUE_HEAD
;
3041 p
->sched_class
= &rt_sched_class
;
3043 if (dl_prio(oldprio
))
3044 p
->dl
.dl_boosted
= 0;
3045 p
->sched_class
= &fair_sched_class
;
3051 p
->sched_class
->set_curr_task(rq
);
3053 enqueue_task(rq
, p
, enqueue_flag
);
3055 check_class_changed(rq
, p
, prev_class
, oldprio
);
3057 __task_rq_unlock(rq
);
3061 void set_user_nice(struct task_struct
*p
, long nice
)
3063 int old_prio
, delta
, on_rq
;
3064 unsigned long flags
;
3067 if (task_nice(p
) == nice
|| nice
< MIN_NICE
|| nice
> MAX_NICE
)
3070 * We have to be careful, if called from sys_setpriority(),
3071 * the task might be in the middle of scheduling on another CPU.
3073 rq
= task_rq_lock(p
, &flags
);
3075 * The RT priorities are set via sched_setscheduler(), but we still
3076 * allow the 'normal' nice value to be set - but as expected
3077 * it wont have any effect on scheduling until the task is
3078 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3080 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
3081 p
->static_prio
= NICE_TO_PRIO(nice
);
3086 dequeue_task(rq
, p
, 0);
3088 p
->static_prio
= NICE_TO_PRIO(nice
);
3091 p
->prio
= effective_prio(p
);
3092 delta
= p
->prio
- old_prio
;
3095 enqueue_task(rq
, p
, 0);
3097 * If the task increased its priority or is running and
3098 * lowered its priority, then reschedule its CPU:
3100 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3104 task_rq_unlock(rq
, p
, &flags
);
3106 EXPORT_SYMBOL(set_user_nice
);
3109 * can_nice - check if a task can reduce its nice value
3113 int can_nice(const struct task_struct
*p
, const int nice
)
3115 /* convert nice value [19,-20] to rlimit style value [1,40] */
3116 int nice_rlim
= nice_to_rlimit(nice
);
3118 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3119 capable(CAP_SYS_NICE
));
3122 #ifdef __ARCH_WANT_SYS_NICE
3125 * sys_nice - change the priority of the current process.
3126 * @increment: priority increment
3128 * sys_setpriority is a more generic, but much slower function that
3129 * does similar things.
3131 SYSCALL_DEFINE1(nice
, int, increment
)
3136 * Setpriority might change our priority at the same moment.
3137 * We don't have to worry. Conceptually one call occurs first
3138 * and we have a single winner.
3140 increment
= clamp(increment
, -NICE_WIDTH
, NICE_WIDTH
);
3141 nice
= task_nice(current
) + increment
;
3143 nice
= clamp_val(nice
, MIN_NICE
, MAX_NICE
);
3144 if (increment
< 0 && !can_nice(current
, nice
))
3147 retval
= security_task_setnice(current
, nice
);
3151 set_user_nice(current
, nice
);
3158 * task_prio - return the priority value of a given task.
3159 * @p: the task in question.
3161 * Return: The priority value as seen by users in /proc.
3162 * RT tasks are offset by -200. Normal tasks are centered
3163 * around 0, value goes from -16 to +15.
3165 int task_prio(const struct task_struct
*p
)
3167 return p
->prio
- MAX_RT_PRIO
;
3171 * idle_cpu - is a given cpu idle currently?
3172 * @cpu: the processor in question.
3174 * Return: 1 if the CPU is currently idle. 0 otherwise.
3176 int idle_cpu(int cpu
)
3178 struct rq
*rq
= cpu_rq(cpu
);
3180 if (rq
->curr
!= rq
->idle
)
3187 if (!llist_empty(&rq
->wake_list
))
3195 * idle_task - return the idle task for a given cpu.
3196 * @cpu: the processor in question.
3198 * Return: The idle task for the cpu @cpu.
3200 struct task_struct
*idle_task(int cpu
)
3202 return cpu_rq(cpu
)->idle
;
3206 * find_process_by_pid - find a process with a matching PID value.
3207 * @pid: the pid in question.
3209 * The task of @pid, if found. %NULL otherwise.
3211 static struct task_struct
*find_process_by_pid(pid_t pid
)
3213 return pid
? find_task_by_vpid(pid
) : current
;
3217 * This function initializes the sched_dl_entity of a newly becoming
3218 * SCHED_DEADLINE task.
3220 * Only the static values are considered here, the actual runtime and the
3221 * absolute deadline will be properly calculated when the task is enqueued
3222 * for the first time with its new policy.
3225 __setparam_dl(struct task_struct
*p
, const struct sched_attr
*attr
)
3227 struct sched_dl_entity
*dl_se
= &p
->dl
;
3229 init_dl_task_timer(dl_se
);
3230 dl_se
->dl_runtime
= attr
->sched_runtime
;
3231 dl_se
->dl_deadline
= attr
->sched_deadline
;
3232 dl_se
->dl_period
= attr
->sched_period
?: dl_se
->dl_deadline
;
3233 dl_se
->flags
= attr
->sched_flags
;
3234 dl_se
->dl_bw
= to_ratio(dl_se
->dl_period
, dl_se
->dl_runtime
);
3235 dl_se
->dl_throttled
= 0;
3237 dl_se
->dl_yielded
= 0;
3241 * sched_setparam() passes in -1 for its policy, to let the functions
3242 * it calls know not to change it.
3244 #define SETPARAM_POLICY -1
3246 static void __setscheduler_params(struct task_struct
*p
,
3247 const struct sched_attr
*attr
)
3249 int policy
= attr
->sched_policy
;
3251 if (policy
== SETPARAM_POLICY
)
3256 if (dl_policy(policy
))
3257 __setparam_dl(p
, attr
);
3258 else if (fair_policy(policy
))
3259 p
->static_prio
= NICE_TO_PRIO(attr
->sched_nice
);
3262 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3263 * !rt_policy. Always setting this ensures that things like
3264 * getparam()/getattr() don't report silly values for !rt tasks.
3266 p
->rt_priority
= attr
->sched_priority
;
3267 p
->normal_prio
= normal_prio(p
);
3271 /* Actually do priority change: must hold pi & rq lock. */
3272 static void __setscheduler(struct rq
*rq
, struct task_struct
*p
,
3273 const struct sched_attr
*attr
)
3275 __setscheduler_params(p
, attr
);
3278 * If we get here, there was no pi waiters boosting the
3279 * task. It is safe to use the normal prio.
3281 p
->prio
= normal_prio(p
);
3283 if (dl_prio(p
->prio
))
3284 p
->sched_class
= &dl_sched_class
;
3285 else if (rt_prio(p
->prio
))
3286 p
->sched_class
= &rt_sched_class
;
3288 p
->sched_class
= &fair_sched_class
;
3292 __getparam_dl(struct task_struct
*p
, struct sched_attr
*attr
)
3294 struct sched_dl_entity
*dl_se
= &p
->dl
;
3296 attr
->sched_priority
= p
->rt_priority
;
3297 attr
->sched_runtime
= dl_se
->dl_runtime
;
3298 attr
->sched_deadline
= dl_se
->dl_deadline
;
3299 attr
->sched_period
= dl_se
->dl_period
;
3300 attr
->sched_flags
= dl_se
->flags
;
3304 * This function validates the new parameters of a -deadline task.
3305 * We ask for the deadline not being zero, and greater or equal
3306 * than the runtime, as well as the period of being zero or
3307 * greater than deadline. Furthermore, we have to be sure that
3308 * user parameters are above the internal resolution of 1us (we
3309 * check sched_runtime only since it is always the smaller one) and
3310 * below 2^63 ns (we have to check both sched_deadline and
3311 * sched_period, as the latter can be zero).
3314 __checkparam_dl(const struct sched_attr
*attr
)
3317 if (attr
->sched_deadline
== 0)
3321 * Since we truncate DL_SCALE bits, make sure we're at least
3324 if (attr
->sched_runtime
< (1ULL << DL_SCALE
))
3328 * Since we use the MSB for wrap-around and sign issues, make
3329 * sure it's not set (mind that period can be equal to zero).
3331 if (attr
->sched_deadline
& (1ULL << 63) ||
3332 attr
->sched_period
& (1ULL << 63))
3335 /* runtime <= deadline <= period (if period != 0) */
3336 if ((attr
->sched_period
!= 0 &&
3337 attr
->sched_period
< attr
->sched_deadline
) ||
3338 attr
->sched_deadline
< attr
->sched_runtime
)
3345 * check the target process has a UID that matches the current process's
3347 static bool check_same_owner(struct task_struct
*p
)
3349 const struct cred
*cred
= current_cred(), *pcred
;
3353 pcred
= __task_cred(p
);
3354 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3355 uid_eq(cred
->euid
, pcred
->uid
));
3360 static int __sched_setscheduler(struct task_struct
*p
,
3361 const struct sched_attr
*attr
,
3364 int newprio
= dl_policy(attr
->sched_policy
) ? MAX_DL_PRIO
- 1 :
3365 MAX_RT_PRIO
- 1 - attr
->sched_priority
;
3366 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
3367 int policy
= attr
->sched_policy
;
3368 unsigned long flags
;
3369 const struct sched_class
*prev_class
;
3373 /* may grab non-irq protected spin_locks */
3374 BUG_ON(in_interrupt());
3376 /* double check policy once rq lock held */
3378 reset_on_fork
= p
->sched_reset_on_fork
;
3379 policy
= oldpolicy
= p
->policy
;
3381 reset_on_fork
= !!(attr
->sched_flags
& SCHED_FLAG_RESET_ON_FORK
);
3383 if (policy
!= SCHED_DEADLINE
&&
3384 policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3385 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3386 policy
!= SCHED_IDLE
)
3390 if (attr
->sched_flags
& ~(SCHED_FLAG_RESET_ON_FORK
))
3394 * Valid priorities for SCHED_FIFO and SCHED_RR are
3395 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3396 * SCHED_BATCH and SCHED_IDLE is 0.
3398 if ((p
->mm
&& attr
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3399 (!p
->mm
&& attr
->sched_priority
> MAX_RT_PRIO
-1))
3401 if ((dl_policy(policy
) && !__checkparam_dl(attr
)) ||
3402 (rt_policy(policy
) != (attr
->sched_priority
!= 0)))
3406 * Allow unprivileged RT tasks to decrease priority:
3408 if (user
&& !capable(CAP_SYS_NICE
)) {
3409 if (fair_policy(policy
)) {
3410 if (attr
->sched_nice
< task_nice(p
) &&
3411 !can_nice(p
, attr
->sched_nice
))
3415 if (rt_policy(policy
)) {
3416 unsigned long rlim_rtprio
=
3417 task_rlimit(p
, RLIMIT_RTPRIO
);
3419 /* can't set/change the rt policy */
3420 if (policy
!= p
->policy
&& !rlim_rtprio
)
3423 /* can't increase priority */
3424 if (attr
->sched_priority
> p
->rt_priority
&&
3425 attr
->sched_priority
> rlim_rtprio
)
3430 * Can't set/change SCHED_DEADLINE policy at all for now
3431 * (safest behavior); in the future we would like to allow
3432 * unprivileged DL tasks to increase their relative deadline
3433 * or reduce their runtime (both ways reducing utilization)
3435 if (dl_policy(policy
))
3439 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3440 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3442 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3443 if (!can_nice(p
, task_nice(p
)))
3447 /* can't change other user's priorities */
3448 if (!check_same_owner(p
))
3451 /* Normal users shall not reset the sched_reset_on_fork flag */
3452 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3457 retval
= security_task_setscheduler(p
);
3463 * make sure no PI-waiters arrive (or leave) while we are
3464 * changing the priority of the task:
3466 * To be able to change p->policy safely, the appropriate
3467 * runqueue lock must be held.
3469 rq
= task_rq_lock(p
, &flags
);
3472 * Changing the policy of the stop threads its a very bad idea
3474 if (p
== rq
->stop
) {
3475 task_rq_unlock(rq
, p
, &flags
);
3480 * If not changing anything there's no need to proceed further,
3481 * but store a possible modification of reset_on_fork.
3483 if (unlikely(policy
== p
->policy
)) {
3484 if (fair_policy(policy
) && attr
->sched_nice
!= task_nice(p
))
3486 if (rt_policy(policy
) && attr
->sched_priority
!= p
->rt_priority
)
3488 if (dl_policy(policy
))
3491 p
->sched_reset_on_fork
= reset_on_fork
;
3492 task_rq_unlock(rq
, p
, &flags
);
3498 #ifdef CONFIG_RT_GROUP_SCHED
3500 * Do not allow realtime tasks into groups that have no runtime
3503 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3504 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3505 !task_group_is_autogroup(task_group(p
))) {
3506 task_rq_unlock(rq
, p
, &flags
);
3511 if (dl_bandwidth_enabled() && dl_policy(policy
)) {
3512 cpumask_t
*span
= rq
->rd
->span
;
3515 * Don't allow tasks with an affinity mask smaller than
3516 * the entire root_domain to become SCHED_DEADLINE. We
3517 * will also fail if there's no bandwidth available.
3519 if (!cpumask_subset(span
, &p
->cpus_allowed
) ||
3520 rq
->rd
->dl_bw
.bw
== 0) {
3521 task_rq_unlock(rq
, p
, &flags
);
3528 /* recheck policy now with rq lock held */
3529 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3530 policy
= oldpolicy
= -1;
3531 task_rq_unlock(rq
, p
, &flags
);
3536 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3537 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3540 if ((dl_policy(policy
) || dl_task(p
)) && dl_overflow(p
, policy
, attr
)) {
3541 task_rq_unlock(rq
, p
, &flags
);
3545 p
->sched_reset_on_fork
= reset_on_fork
;
3549 * Special case for priority boosted tasks.
3551 * If the new priority is lower or equal (user space view)
3552 * than the current (boosted) priority, we just store the new
3553 * normal parameters and do not touch the scheduler class and
3554 * the runqueue. This will be done when the task deboost
3557 if (rt_mutex_check_prio(p
, newprio
)) {
3558 __setscheduler_params(p
, attr
);
3559 task_rq_unlock(rq
, p
, &flags
);
3564 running
= task_current(rq
, p
);
3566 dequeue_task(rq
, p
, 0);
3568 p
->sched_class
->put_prev_task(rq
, p
);
3570 prev_class
= p
->sched_class
;
3571 __setscheduler(rq
, p
, attr
);
3574 p
->sched_class
->set_curr_task(rq
);
3577 * We enqueue to tail when the priority of a task is
3578 * increased (user space view).
3580 enqueue_task(rq
, p
, oldprio
<= p
->prio
? ENQUEUE_HEAD
: 0);
3583 check_class_changed(rq
, p
, prev_class
, oldprio
);
3584 task_rq_unlock(rq
, p
, &flags
);
3586 rt_mutex_adjust_pi(p
);
3591 static int _sched_setscheduler(struct task_struct
*p
, int policy
,
3592 const struct sched_param
*param
, bool check
)
3594 struct sched_attr attr
= {
3595 .sched_policy
= policy
,
3596 .sched_priority
= param
->sched_priority
,
3597 .sched_nice
= PRIO_TO_NICE(p
->static_prio
),
3600 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
3601 if ((policy
!= SETPARAM_POLICY
) && (policy
& SCHED_RESET_ON_FORK
)) {
3602 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3603 policy
&= ~SCHED_RESET_ON_FORK
;
3604 attr
.sched_policy
= policy
;
3607 return __sched_setscheduler(p
, &attr
, check
);
3610 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3611 * @p: the task in question.
3612 * @policy: new policy.
3613 * @param: structure containing the new RT priority.
3615 * Return: 0 on success. An error code otherwise.
3617 * NOTE that the task may be already dead.
3619 int sched_setscheduler(struct task_struct
*p
, int policy
,
3620 const struct sched_param
*param
)
3622 return _sched_setscheduler(p
, policy
, param
, true);
3624 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3626 int sched_setattr(struct task_struct
*p
, const struct sched_attr
*attr
)
3628 return __sched_setscheduler(p
, attr
, true);
3630 EXPORT_SYMBOL_GPL(sched_setattr
);
3633 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3634 * @p: the task in question.
3635 * @policy: new policy.
3636 * @param: structure containing the new RT priority.
3638 * Just like sched_setscheduler, only don't bother checking if the
3639 * current context has permission. For example, this is needed in
3640 * stop_machine(): we create temporary high priority worker threads,
3641 * but our caller might not have that capability.
3643 * Return: 0 on success. An error code otherwise.
3645 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3646 const struct sched_param
*param
)
3648 return _sched_setscheduler(p
, policy
, param
, false);
3652 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3654 struct sched_param lparam
;
3655 struct task_struct
*p
;
3658 if (!param
|| pid
< 0)
3660 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3665 p
= find_process_by_pid(pid
);
3667 retval
= sched_setscheduler(p
, policy
, &lparam
);
3674 * Mimics kernel/events/core.c perf_copy_attr().
3676 static int sched_copy_attr(struct sched_attr __user
*uattr
,
3677 struct sched_attr
*attr
)
3682 if (!access_ok(VERIFY_WRITE
, uattr
, SCHED_ATTR_SIZE_VER0
))
3686 * zero the full structure, so that a short copy will be nice.
3688 memset(attr
, 0, sizeof(*attr
));
3690 ret
= get_user(size
, &uattr
->size
);
3694 if (size
> PAGE_SIZE
) /* silly large */
3697 if (!size
) /* abi compat */
3698 size
= SCHED_ATTR_SIZE_VER0
;
3700 if (size
< SCHED_ATTR_SIZE_VER0
)
3704 * If we're handed a bigger struct than we know of,
3705 * ensure all the unknown bits are 0 - i.e. new
3706 * user-space does not rely on any kernel feature
3707 * extensions we dont know about yet.
3709 if (size
> sizeof(*attr
)) {
3710 unsigned char __user
*addr
;
3711 unsigned char __user
*end
;
3714 addr
= (void __user
*)uattr
+ sizeof(*attr
);
3715 end
= (void __user
*)uattr
+ size
;
3717 for (; addr
< end
; addr
++) {
3718 ret
= get_user(val
, addr
);
3724 size
= sizeof(*attr
);
3727 ret
= copy_from_user(attr
, uattr
, size
);
3732 * XXX: do we want to be lenient like existing syscalls; or do we want
3733 * to be strict and return an error on out-of-bounds values?
3735 attr
->sched_nice
= clamp(attr
->sched_nice
, MIN_NICE
, MAX_NICE
);
3740 put_user(sizeof(*attr
), &uattr
->size
);
3745 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3746 * @pid: the pid in question.
3747 * @policy: new policy.
3748 * @param: structure containing the new RT priority.
3750 * Return: 0 on success. An error code otherwise.
3752 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3753 struct sched_param __user
*, param
)
3755 /* negative values for policy are not valid */
3759 return do_sched_setscheduler(pid
, policy
, param
);
3763 * sys_sched_setparam - set/change the RT priority of a thread
3764 * @pid: the pid in question.
3765 * @param: structure containing the new RT priority.
3767 * Return: 0 on success. An error code otherwise.
3769 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3771 return do_sched_setscheduler(pid
, SETPARAM_POLICY
, param
);
3775 * sys_sched_setattr - same as above, but with extended sched_attr
3776 * @pid: the pid in question.
3777 * @uattr: structure containing the extended parameters.
3778 * @flags: for future extension.
3780 SYSCALL_DEFINE3(sched_setattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3781 unsigned int, flags
)
3783 struct sched_attr attr
;
3784 struct task_struct
*p
;
3787 if (!uattr
|| pid
< 0 || flags
)
3790 retval
= sched_copy_attr(uattr
, &attr
);
3794 if ((int)attr
.sched_policy
< 0)
3799 p
= find_process_by_pid(pid
);
3801 retval
= sched_setattr(p
, &attr
);
3808 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3809 * @pid: the pid in question.
3811 * Return: On success, the policy of the thread. Otherwise, a negative error
3814 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3816 struct task_struct
*p
;
3824 p
= find_process_by_pid(pid
);
3826 retval
= security_task_getscheduler(p
);
3829 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3836 * sys_sched_getparam - get the RT priority of a thread
3837 * @pid: the pid in question.
3838 * @param: structure containing the RT priority.
3840 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3843 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3845 struct sched_param lp
= { .sched_priority
= 0 };
3846 struct task_struct
*p
;
3849 if (!param
|| pid
< 0)
3853 p
= find_process_by_pid(pid
);
3858 retval
= security_task_getscheduler(p
);
3862 if (task_has_rt_policy(p
))
3863 lp
.sched_priority
= p
->rt_priority
;
3867 * This one might sleep, we cannot do it with a spinlock held ...
3869 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3878 static int sched_read_attr(struct sched_attr __user
*uattr
,
3879 struct sched_attr
*attr
,
3884 if (!access_ok(VERIFY_WRITE
, uattr
, usize
))
3888 * If we're handed a smaller struct than we know of,
3889 * ensure all the unknown bits are 0 - i.e. old
3890 * user-space does not get uncomplete information.
3892 if (usize
< sizeof(*attr
)) {
3893 unsigned char *addr
;
3896 addr
= (void *)attr
+ usize
;
3897 end
= (void *)attr
+ sizeof(*attr
);
3899 for (; addr
< end
; addr
++) {
3907 ret
= copy_to_user(uattr
, attr
, attr
->size
);
3915 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
3916 * @pid: the pid in question.
3917 * @uattr: structure containing the extended parameters.
3918 * @size: sizeof(attr) for fwd/bwd comp.
3919 * @flags: for future extension.
3921 SYSCALL_DEFINE4(sched_getattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3922 unsigned int, size
, unsigned int, flags
)
3924 struct sched_attr attr
= {
3925 .size
= sizeof(struct sched_attr
),
3927 struct task_struct
*p
;
3930 if (!uattr
|| pid
< 0 || size
> PAGE_SIZE
||
3931 size
< SCHED_ATTR_SIZE_VER0
|| flags
)
3935 p
= find_process_by_pid(pid
);
3940 retval
= security_task_getscheduler(p
);
3944 attr
.sched_policy
= p
->policy
;
3945 if (p
->sched_reset_on_fork
)
3946 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3947 if (task_has_dl_policy(p
))
3948 __getparam_dl(p
, &attr
);
3949 else if (task_has_rt_policy(p
))
3950 attr
.sched_priority
= p
->rt_priority
;
3952 attr
.sched_nice
= task_nice(p
);
3956 retval
= sched_read_attr(uattr
, &attr
, size
);
3964 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
3966 cpumask_var_t cpus_allowed
, new_mask
;
3967 struct task_struct
*p
;
3972 p
= find_process_by_pid(pid
);
3978 /* Prevent p going away */
3982 if (p
->flags
& PF_NO_SETAFFINITY
) {
3986 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
3990 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
3992 goto out_free_cpus_allowed
;
3995 if (!check_same_owner(p
)) {
3997 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
4004 retval
= security_task_setscheduler(p
);
4009 cpuset_cpus_allowed(p
, cpus_allowed
);
4010 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4013 * Since bandwidth control happens on root_domain basis,
4014 * if admission test is enabled, we only admit -deadline
4015 * tasks allowed to run on all the CPUs in the task's
4019 if (task_has_dl_policy(p
)) {
4020 const struct cpumask
*span
= task_rq(p
)->rd
->span
;
4022 if (dl_bandwidth_enabled() && !cpumask_subset(span
, new_mask
)) {
4029 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4032 cpuset_cpus_allowed(p
, cpus_allowed
);
4033 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4035 * We must have raced with a concurrent cpuset
4036 * update. Just reset the cpus_allowed to the
4037 * cpuset's cpus_allowed
4039 cpumask_copy(new_mask
, cpus_allowed
);
4044 free_cpumask_var(new_mask
);
4045 out_free_cpus_allowed
:
4046 free_cpumask_var(cpus_allowed
);
4052 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4053 struct cpumask
*new_mask
)
4055 if (len
< cpumask_size())
4056 cpumask_clear(new_mask
);
4057 else if (len
> cpumask_size())
4058 len
= cpumask_size();
4060 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4064 * sys_sched_setaffinity - set the cpu affinity of a process
4065 * @pid: pid of the process
4066 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4067 * @user_mask_ptr: user-space pointer to the new cpu mask
4069 * Return: 0 on success. An error code otherwise.
4071 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4072 unsigned long __user
*, user_mask_ptr
)
4074 cpumask_var_t new_mask
;
4077 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4080 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4082 retval
= sched_setaffinity(pid
, new_mask
);
4083 free_cpumask_var(new_mask
);
4087 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4089 struct task_struct
*p
;
4090 unsigned long flags
;
4096 p
= find_process_by_pid(pid
);
4100 retval
= security_task_getscheduler(p
);
4104 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4105 cpumask_and(mask
, &p
->cpus_allowed
, cpu_active_mask
);
4106 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4115 * sys_sched_getaffinity - get the cpu affinity of a process
4116 * @pid: pid of the process
4117 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4118 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4120 * Return: 0 on success. An error code otherwise.
4122 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4123 unsigned long __user
*, user_mask_ptr
)
4128 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4130 if (len
& (sizeof(unsigned long)-1))
4133 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4136 ret
= sched_getaffinity(pid
, mask
);
4138 size_t retlen
= min_t(size_t, len
, cpumask_size());
4140 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4145 free_cpumask_var(mask
);
4151 * sys_sched_yield - yield the current processor to other threads.
4153 * This function yields the current CPU to other tasks. If there are no
4154 * other threads running on this CPU then this function will return.
4158 SYSCALL_DEFINE0(sched_yield
)
4160 struct rq
*rq
= this_rq_lock();
4162 schedstat_inc(rq
, yld_count
);
4163 current
->sched_class
->yield_task(rq
);
4166 * Since we are going to call schedule() anyway, there's
4167 * no need to preempt or enable interrupts:
4169 __release(rq
->lock
);
4170 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4171 do_raw_spin_unlock(&rq
->lock
);
4172 sched_preempt_enable_no_resched();
4179 static void __cond_resched(void)
4181 __preempt_count_add(PREEMPT_ACTIVE
);
4183 __preempt_count_sub(PREEMPT_ACTIVE
);
4186 int __sched
_cond_resched(void)
4188 if (should_resched()) {
4194 EXPORT_SYMBOL(_cond_resched
);
4197 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4198 * call schedule, and on return reacquire the lock.
4200 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4201 * operations here to prevent schedule() from being called twice (once via
4202 * spin_unlock(), once by hand).
4204 int __cond_resched_lock(spinlock_t
*lock
)
4206 int resched
= should_resched();
4209 lockdep_assert_held(lock
);
4211 if (spin_needbreak(lock
) || resched
) {
4222 EXPORT_SYMBOL(__cond_resched_lock
);
4224 int __sched
__cond_resched_softirq(void)
4226 BUG_ON(!in_softirq());
4228 if (should_resched()) {
4236 EXPORT_SYMBOL(__cond_resched_softirq
);
4239 * yield - yield the current processor to other threads.
4241 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4243 * The scheduler is at all times free to pick the calling task as the most
4244 * eligible task to run, if removing the yield() call from your code breaks
4245 * it, its already broken.
4247 * Typical broken usage is:
4252 * where one assumes that yield() will let 'the other' process run that will
4253 * make event true. If the current task is a SCHED_FIFO task that will never
4254 * happen. Never use yield() as a progress guarantee!!
4256 * If you want to use yield() to wait for something, use wait_event().
4257 * If you want to use yield() to be 'nice' for others, use cond_resched().
4258 * If you still want to use yield(), do not!
4260 void __sched
yield(void)
4262 set_current_state(TASK_RUNNING
);
4265 EXPORT_SYMBOL(yield
);
4268 * yield_to - yield the current processor to another thread in
4269 * your thread group, or accelerate that thread toward the
4270 * processor it's on.
4272 * @preempt: whether task preemption is allowed or not
4274 * It's the caller's job to ensure that the target task struct
4275 * can't go away on us before we can do any checks.
4278 * true (>0) if we indeed boosted the target task.
4279 * false (0) if we failed to boost the target.
4280 * -ESRCH if there's no task to yield to.
4282 int __sched
yield_to(struct task_struct
*p
, bool preempt
)
4284 struct task_struct
*curr
= current
;
4285 struct rq
*rq
, *p_rq
;
4286 unsigned long flags
;
4289 local_irq_save(flags
);
4295 * If we're the only runnable task on the rq and target rq also
4296 * has only one task, there's absolutely no point in yielding.
4298 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
4303 double_rq_lock(rq
, p_rq
);
4304 if (task_rq(p
) != p_rq
) {
4305 double_rq_unlock(rq
, p_rq
);
4309 if (!curr
->sched_class
->yield_to_task
)
4312 if (curr
->sched_class
!= p
->sched_class
)
4315 if (task_running(p_rq
, p
) || p
->state
)
4318 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4320 schedstat_inc(rq
, yld_count
);
4322 * Make p's CPU reschedule; pick_next_entity takes care of
4325 if (preempt
&& rq
!= p_rq
)
4330 double_rq_unlock(rq
, p_rq
);
4332 local_irq_restore(flags
);
4339 EXPORT_SYMBOL_GPL(yield_to
);
4342 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4343 * that process accounting knows that this is a task in IO wait state.
4345 void __sched
io_schedule(void)
4347 struct rq
*rq
= raw_rq();
4349 delayacct_blkio_start();
4350 atomic_inc(&rq
->nr_iowait
);
4351 blk_flush_plug(current
);
4352 current
->in_iowait
= 1;
4354 current
->in_iowait
= 0;
4355 atomic_dec(&rq
->nr_iowait
);
4356 delayacct_blkio_end();
4358 EXPORT_SYMBOL(io_schedule
);
4360 long __sched
io_schedule_timeout(long timeout
)
4362 struct rq
*rq
= raw_rq();
4365 delayacct_blkio_start();
4366 atomic_inc(&rq
->nr_iowait
);
4367 blk_flush_plug(current
);
4368 current
->in_iowait
= 1;
4369 ret
= schedule_timeout(timeout
);
4370 current
->in_iowait
= 0;
4371 atomic_dec(&rq
->nr_iowait
);
4372 delayacct_blkio_end();
4377 * sys_sched_get_priority_max - return maximum RT priority.
4378 * @policy: scheduling class.
4380 * Return: On success, this syscall returns the maximum
4381 * rt_priority that can be used by a given scheduling class.
4382 * On failure, a negative error code is returned.
4384 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4391 ret
= MAX_USER_RT_PRIO
-1;
4393 case SCHED_DEADLINE
:
4404 * sys_sched_get_priority_min - return minimum RT priority.
4405 * @policy: scheduling class.
4407 * Return: On success, this syscall returns the minimum
4408 * rt_priority that can be used by a given scheduling class.
4409 * On failure, a negative error code is returned.
4411 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4420 case SCHED_DEADLINE
:
4430 * sys_sched_rr_get_interval - return the default timeslice of a process.
4431 * @pid: pid of the process.
4432 * @interval: userspace pointer to the timeslice value.
4434 * this syscall writes the default timeslice value of a given process
4435 * into the user-space timespec buffer. A value of '0' means infinity.
4437 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4440 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4441 struct timespec __user
*, interval
)
4443 struct task_struct
*p
;
4444 unsigned int time_slice
;
4445 unsigned long flags
;
4455 p
= find_process_by_pid(pid
);
4459 retval
= security_task_getscheduler(p
);
4463 rq
= task_rq_lock(p
, &flags
);
4465 if (p
->sched_class
->get_rr_interval
)
4466 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4467 task_rq_unlock(rq
, p
, &flags
);
4470 jiffies_to_timespec(time_slice
, &t
);
4471 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4479 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4481 void sched_show_task(struct task_struct
*p
)
4483 unsigned long free
= 0;
4487 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4488 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4489 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4490 #if BITS_PER_LONG == 32
4491 if (state
== TASK_RUNNING
)
4492 printk(KERN_CONT
" running ");
4494 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4496 if (state
== TASK_RUNNING
)
4497 printk(KERN_CONT
" running task ");
4499 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4501 #ifdef CONFIG_DEBUG_STACK_USAGE
4502 free
= stack_not_used(p
);
4505 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4507 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4508 task_pid_nr(p
), ppid
,
4509 (unsigned long)task_thread_info(p
)->flags
);
4511 print_worker_info(KERN_INFO
, p
);
4512 show_stack(p
, NULL
);
4515 void show_state_filter(unsigned long state_filter
)
4517 struct task_struct
*g
, *p
;
4519 #if BITS_PER_LONG == 32
4521 " task PC stack pid father\n");
4524 " task PC stack pid father\n");
4527 do_each_thread(g
, p
) {
4529 * reset the NMI-timeout, listing all files on a slow
4530 * console might take a lot of time:
4532 touch_nmi_watchdog();
4533 if (!state_filter
|| (p
->state
& state_filter
))
4535 } while_each_thread(g
, p
);
4537 touch_all_softlockup_watchdogs();
4539 #ifdef CONFIG_SCHED_DEBUG
4540 sysrq_sched_debug_show();
4544 * Only show locks if all tasks are dumped:
4547 debug_show_all_locks();
4550 void init_idle_bootup_task(struct task_struct
*idle
)
4552 idle
->sched_class
= &idle_sched_class
;
4556 * init_idle - set up an idle thread for a given CPU
4557 * @idle: task in question
4558 * @cpu: cpu the idle task belongs to
4560 * NOTE: this function does not set the idle thread's NEED_RESCHED
4561 * flag, to make booting more robust.
4563 void init_idle(struct task_struct
*idle
, int cpu
)
4565 struct rq
*rq
= cpu_rq(cpu
);
4566 unsigned long flags
;
4568 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4570 __sched_fork(0, idle
);
4571 idle
->state
= TASK_RUNNING
;
4572 idle
->se
.exec_start
= sched_clock();
4574 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4576 * We're having a chicken and egg problem, even though we are
4577 * holding rq->lock, the cpu isn't yet set to this cpu so the
4578 * lockdep check in task_group() will fail.
4580 * Similar case to sched_fork(). / Alternatively we could
4581 * use task_rq_lock() here and obtain the other rq->lock.
4586 __set_task_cpu(idle
, cpu
);
4589 rq
->curr
= rq
->idle
= idle
;
4591 #if defined(CONFIG_SMP)
4594 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4596 /* Set the preempt count _outside_ the spinlocks! */
4597 init_idle_preempt_count(idle
, cpu
);
4600 * The idle tasks have their own, simple scheduling class:
4602 idle
->sched_class
= &idle_sched_class
;
4603 ftrace_graph_init_idle_task(idle
, cpu
);
4604 vtime_init_idle(idle
, cpu
);
4605 #if defined(CONFIG_SMP)
4606 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4611 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4613 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4614 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4616 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4617 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4621 * This is how migration works:
4623 * 1) we invoke migration_cpu_stop() on the target CPU using
4625 * 2) stopper starts to run (implicitly forcing the migrated thread
4627 * 3) it checks whether the migrated task is still in the wrong runqueue.
4628 * 4) if it's in the wrong runqueue then the migration thread removes
4629 * it and puts it into the right queue.
4630 * 5) stopper completes and stop_one_cpu() returns and the migration
4635 * Change a given task's CPU affinity. Migrate the thread to a
4636 * proper CPU and schedule it away if the CPU it's executing on
4637 * is removed from the allowed bitmask.
4639 * NOTE: the caller must have a valid reference to the task, the
4640 * task must not exit() & deallocate itself prematurely. The
4641 * call is not atomic; no spinlocks may be held.
4643 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4645 unsigned long flags
;
4647 unsigned int dest_cpu
;
4650 rq
= task_rq_lock(p
, &flags
);
4652 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4655 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4660 do_set_cpus_allowed(p
, new_mask
);
4662 /* Can the task run on the task's current CPU? If so, we're done */
4663 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4666 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4668 struct migration_arg arg
= { p
, dest_cpu
};
4669 /* Need help from migration thread: drop lock and wait. */
4670 task_rq_unlock(rq
, p
, &flags
);
4671 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4672 tlb_migrate_finish(p
->mm
);
4676 task_rq_unlock(rq
, p
, &flags
);
4680 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4683 * Move (not current) task off this cpu, onto dest cpu. We're doing
4684 * this because either it can't run here any more (set_cpus_allowed()
4685 * away from this CPU, or CPU going down), or because we're
4686 * attempting to rebalance this task on exec (sched_exec).
4688 * So we race with normal scheduler movements, but that's OK, as long
4689 * as the task is no longer on this CPU.
4691 * Returns non-zero if task was successfully migrated.
4693 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4695 struct rq
*rq_dest
, *rq_src
;
4698 if (unlikely(!cpu_active(dest_cpu
)))
4701 rq_src
= cpu_rq(src_cpu
);
4702 rq_dest
= cpu_rq(dest_cpu
);
4704 raw_spin_lock(&p
->pi_lock
);
4705 double_rq_lock(rq_src
, rq_dest
);
4706 /* Already moved. */
4707 if (task_cpu(p
) != src_cpu
)
4709 /* Affinity changed (again). */
4710 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4714 * If we're not on a rq, the next wake-up will ensure we're
4718 dequeue_task(rq_src
, p
, 0);
4719 set_task_cpu(p
, dest_cpu
);
4720 enqueue_task(rq_dest
, p
, 0);
4721 check_preempt_curr(rq_dest
, p
, 0);
4726 double_rq_unlock(rq_src
, rq_dest
);
4727 raw_spin_unlock(&p
->pi_lock
);
4731 #ifdef CONFIG_NUMA_BALANCING
4732 /* Migrate current task p to target_cpu */
4733 int migrate_task_to(struct task_struct
*p
, int target_cpu
)
4735 struct migration_arg arg
= { p
, target_cpu
};
4736 int curr_cpu
= task_cpu(p
);
4738 if (curr_cpu
== target_cpu
)
4741 if (!cpumask_test_cpu(target_cpu
, tsk_cpus_allowed(p
)))
4744 /* TODO: This is not properly updating schedstats */
4746 trace_sched_move_numa(p
, curr_cpu
, target_cpu
);
4747 return stop_one_cpu(curr_cpu
, migration_cpu_stop
, &arg
);
4751 * Requeue a task on a given node and accurately track the number of NUMA
4752 * tasks on the runqueues
4754 void sched_setnuma(struct task_struct
*p
, int nid
)
4757 unsigned long flags
;
4758 bool on_rq
, running
;
4760 rq
= task_rq_lock(p
, &flags
);
4762 running
= task_current(rq
, p
);
4765 dequeue_task(rq
, p
, 0);
4767 p
->sched_class
->put_prev_task(rq
, p
);
4769 p
->numa_preferred_nid
= nid
;
4772 p
->sched_class
->set_curr_task(rq
);
4774 enqueue_task(rq
, p
, 0);
4775 task_rq_unlock(rq
, p
, &flags
);
4780 * migration_cpu_stop - this will be executed by a highprio stopper thread
4781 * and performs thread migration by bumping thread off CPU then
4782 * 'pushing' onto another runqueue.
4784 static int migration_cpu_stop(void *data
)
4786 struct migration_arg
*arg
= data
;
4789 * The original target cpu might have gone down and we might
4790 * be on another cpu but it doesn't matter.
4792 local_irq_disable();
4793 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4798 #ifdef CONFIG_HOTPLUG_CPU
4801 * Ensures that the idle task is using init_mm right before its cpu goes
4804 void idle_task_exit(void)
4806 struct mm_struct
*mm
= current
->active_mm
;
4808 BUG_ON(cpu_online(smp_processor_id()));
4810 if (mm
!= &init_mm
) {
4811 switch_mm(mm
, &init_mm
, current
);
4812 finish_arch_post_lock_switch();
4818 * Since this CPU is going 'away' for a while, fold any nr_active delta
4819 * we might have. Assumes we're called after migrate_tasks() so that the
4820 * nr_active count is stable.
4822 * Also see the comment "Global load-average calculations".
4824 static void calc_load_migrate(struct rq
*rq
)
4826 long delta
= calc_load_fold_active(rq
);
4828 atomic_long_add(delta
, &calc_load_tasks
);
4831 static void put_prev_task_fake(struct rq
*rq
, struct task_struct
*prev
)
4835 static const struct sched_class fake_sched_class
= {
4836 .put_prev_task
= put_prev_task_fake
,
4839 static struct task_struct fake_task
= {
4841 * Avoid pull_{rt,dl}_task()
4843 .prio
= MAX_PRIO
+ 1,
4844 .sched_class
= &fake_sched_class
,
4848 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4849 * try_to_wake_up()->select_task_rq().
4851 * Called with rq->lock held even though we'er in stop_machine() and
4852 * there's no concurrency possible, we hold the required locks anyway
4853 * because of lock validation efforts.
4855 static void migrate_tasks(unsigned int dead_cpu
)
4857 struct rq
*rq
= cpu_rq(dead_cpu
);
4858 struct task_struct
*next
, *stop
= rq
->stop
;
4862 * Fudge the rq selection such that the below task selection loop
4863 * doesn't get stuck on the currently eligible stop task.
4865 * We're currently inside stop_machine() and the rq is either stuck
4866 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4867 * either way we should never end up calling schedule() until we're
4873 * put_prev_task() and pick_next_task() sched
4874 * class method both need to have an up-to-date
4875 * value of rq->clock[_task]
4877 update_rq_clock(rq
);
4881 * There's this thread running, bail when that's the only
4884 if (rq
->nr_running
== 1)
4887 next
= pick_next_task(rq
, &fake_task
);
4889 next
->sched_class
->put_prev_task(rq
, next
);
4891 /* Find suitable destination for @next, with force if needed. */
4892 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
4893 raw_spin_unlock(&rq
->lock
);
4895 __migrate_task(next
, dead_cpu
, dest_cpu
);
4897 raw_spin_lock(&rq
->lock
);
4903 #endif /* CONFIG_HOTPLUG_CPU */
4905 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4907 static struct ctl_table sd_ctl_dir
[] = {
4909 .procname
= "sched_domain",
4915 static struct ctl_table sd_ctl_root
[] = {
4917 .procname
= "kernel",
4919 .child
= sd_ctl_dir
,
4924 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
4926 struct ctl_table
*entry
=
4927 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
4932 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
4934 struct ctl_table
*entry
;
4937 * In the intermediate directories, both the child directory and
4938 * procname are dynamically allocated and could fail but the mode
4939 * will always be set. In the lowest directory the names are
4940 * static strings and all have proc handlers.
4942 for (entry
= *tablep
; entry
->mode
; entry
++) {
4944 sd_free_ctl_entry(&entry
->child
);
4945 if (entry
->proc_handler
== NULL
)
4946 kfree(entry
->procname
);
4953 static int min_load_idx
= 0;
4954 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
4957 set_table_entry(struct ctl_table
*entry
,
4958 const char *procname
, void *data
, int maxlen
,
4959 umode_t mode
, proc_handler
*proc_handler
,
4962 entry
->procname
= procname
;
4964 entry
->maxlen
= maxlen
;
4966 entry
->proc_handler
= proc_handler
;
4969 entry
->extra1
= &min_load_idx
;
4970 entry
->extra2
= &max_load_idx
;
4974 static struct ctl_table
*
4975 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
4977 struct ctl_table
*table
= sd_alloc_ctl_entry(14);
4982 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
4983 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4984 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
4985 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4986 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
4987 sizeof(int), 0644, proc_dointvec_minmax
, true);
4988 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
4989 sizeof(int), 0644, proc_dointvec_minmax
, true);
4990 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
4991 sizeof(int), 0644, proc_dointvec_minmax
, true);
4992 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
4993 sizeof(int), 0644, proc_dointvec_minmax
, true);
4994 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
4995 sizeof(int), 0644, proc_dointvec_minmax
, true);
4996 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
4997 sizeof(int), 0644, proc_dointvec_minmax
, false);
4998 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
4999 sizeof(int), 0644, proc_dointvec_minmax
, false);
5000 set_table_entry(&table
[9], "cache_nice_tries",
5001 &sd
->cache_nice_tries
,
5002 sizeof(int), 0644, proc_dointvec_minmax
, false);
5003 set_table_entry(&table
[10], "flags", &sd
->flags
,
5004 sizeof(int), 0644, proc_dointvec_minmax
, false);
5005 set_table_entry(&table
[11], "max_newidle_lb_cost",
5006 &sd
->max_newidle_lb_cost
,
5007 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5008 set_table_entry(&table
[12], "name", sd
->name
,
5009 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
5010 /* &table[13] is terminator */
5015 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5017 struct ctl_table
*entry
, *table
;
5018 struct sched_domain
*sd
;
5019 int domain_num
= 0, i
;
5022 for_each_domain(cpu
, sd
)
5024 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5029 for_each_domain(cpu
, sd
) {
5030 snprintf(buf
, 32, "domain%d", i
);
5031 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5033 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5040 static struct ctl_table_header
*sd_sysctl_header
;
5041 static void register_sched_domain_sysctl(void)
5043 int i
, cpu_num
= num_possible_cpus();
5044 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5047 WARN_ON(sd_ctl_dir
[0].child
);
5048 sd_ctl_dir
[0].child
= entry
;
5053 for_each_possible_cpu(i
) {
5054 snprintf(buf
, 32, "cpu%d", i
);
5055 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5057 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5061 WARN_ON(sd_sysctl_header
);
5062 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5065 /* may be called multiple times per register */
5066 static void unregister_sched_domain_sysctl(void)
5068 if (sd_sysctl_header
)
5069 unregister_sysctl_table(sd_sysctl_header
);
5070 sd_sysctl_header
= NULL
;
5071 if (sd_ctl_dir
[0].child
)
5072 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5075 static void register_sched_domain_sysctl(void)
5078 static void unregister_sched_domain_sysctl(void)
5083 static void set_rq_online(struct rq
*rq
)
5086 const struct sched_class
*class;
5088 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5091 for_each_class(class) {
5092 if (class->rq_online
)
5093 class->rq_online(rq
);
5098 static void set_rq_offline(struct rq
*rq
)
5101 const struct sched_class
*class;
5103 for_each_class(class) {
5104 if (class->rq_offline
)
5105 class->rq_offline(rq
);
5108 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5114 * migration_call - callback that gets triggered when a CPU is added.
5115 * Here we can start up the necessary migration thread for the new CPU.
5118 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5120 int cpu
= (long)hcpu
;
5121 unsigned long flags
;
5122 struct rq
*rq
= cpu_rq(cpu
);
5124 switch (action
& ~CPU_TASKS_FROZEN
) {
5126 case CPU_UP_PREPARE
:
5127 rq
->calc_load_update
= calc_load_update
;
5131 /* Update our root-domain */
5132 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5134 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5138 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5141 #ifdef CONFIG_HOTPLUG_CPU
5143 sched_ttwu_pending();
5144 /* Update our root-domain */
5145 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5147 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5151 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5152 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5156 calc_load_migrate(rq
);
5161 update_max_interval();
5167 * Register at high priority so that task migration (migrate_all_tasks)
5168 * happens before everything else. This has to be lower priority than
5169 * the notifier in the perf_event subsystem, though.
5171 static struct notifier_block migration_notifier
= {
5172 .notifier_call
= migration_call
,
5173 .priority
= CPU_PRI_MIGRATION
,
5176 static void __cpuinit
set_cpu_rq_start_time(void)
5178 int cpu
= smp_processor_id();
5179 struct rq
*rq
= cpu_rq(cpu
);
5180 rq
->age_stamp
= sched_clock_cpu(cpu
);
5183 static int sched_cpu_active(struct notifier_block
*nfb
,
5184 unsigned long action
, void *hcpu
)
5186 switch (action
& ~CPU_TASKS_FROZEN
) {
5188 set_cpu_rq_start_time();
5190 case CPU_DOWN_FAILED
:
5191 set_cpu_active((long)hcpu
, true);
5198 static int sched_cpu_inactive(struct notifier_block
*nfb
,
5199 unsigned long action
, void *hcpu
)
5201 unsigned long flags
;
5202 long cpu
= (long)hcpu
;
5204 switch (action
& ~CPU_TASKS_FROZEN
) {
5205 case CPU_DOWN_PREPARE
:
5206 set_cpu_active(cpu
, false);
5208 /* explicitly allow suspend */
5209 if (!(action
& CPU_TASKS_FROZEN
)) {
5210 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
5214 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
5215 cpus
= dl_bw_cpus(cpu
);
5216 overflow
= __dl_overflow(dl_b
, cpus
, 0, 0);
5217 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
5220 return notifier_from_errno(-EBUSY
);
5228 static int __init
migration_init(void)
5230 void *cpu
= (void *)(long)smp_processor_id();
5233 /* Initialize migration for the boot CPU */
5234 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5235 BUG_ON(err
== NOTIFY_BAD
);
5236 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5237 register_cpu_notifier(&migration_notifier
);
5239 /* Register cpu active notifiers */
5240 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5241 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5245 early_initcall(migration_init
);
5250 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5252 #ifdef CONFIG_SCHED_DEBUG
5254 static __read_mostly
int sched_debug_enabled
;
5256 static int __init
sched_debug_setup(char *str
)
5258 sched_debug_enabled
= 1;
5262 early_param("sched_debug", sched_debug_setup
);
5264 static inline bool sched_debug(void)
5266 return sched_debug_enabled
;
5269 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5270 struct cpumask
*groupmask
)
5272 struct sched_group
*group
= sd
->groups
;
5275 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5276 cpumask_clear(groupmask
);
5278 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5280 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5281 printk("does not load-balance\n");
5283 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5288 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5290 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5291 printk(KERN_ERR
"ERROR: domain->span does not contain "
5294 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5295 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5299 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5303 printk(KERN_ERR
"ERROR: group is NULL\n");
5308 * Even though we initialize ->capacity to something semi-sane,
5309 * we leave capacity_orig unset. This allows us to detect if
5310 * domain iteration is still funny without causing /0 traps.
5312 if (!group
->sgc
->capacity_orig
) {
5313 printk(KERN_CONT
"\n");
5314 printk(KERN_ERR
"ERROR: domain->cpu_capacity not set\n");
5318 if (!cpumask_weight(sched_group_cpus(group
))) {
5319 printk(KERN_CONT
"\n");
5320 printk(KERN_ERR
"ERROR: empty group\n");
5324 if (!(sd
->flags
& SD_OVERLAP
) &&
5325 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5326 printk(KERN_CONT
"\n");
5327 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5331 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5333 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
5335 printk(KERN_CONT
" %s", str
);
5336 if (group
->sgc
->capacity
!= SCHED_CAPACITY_SCALE
) {
5337 printk(KERN_CONT
" (cpu_capacity = %d)",
5338 group
->sgc
->capacity
);
5341 group
= group
->next
;
5342 } while (group
!= sd
->groups
);
5343 printk(KERN_CONT
"\n");
5345 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5346 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5349 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5350 printk(KERN_ERR
"ERROR: parent span is not a superset "
5351 "of domain->span\n");
5355 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5359 if (!sched_debug_enabled
)
5363 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5367 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5370 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5378 #else /* !CONFIG_SCHED_DEBUG */
5379 # define sched_domain_debug(sd, cpu) do { } while (0)
5380 static inline bool sched_debug(void)
5384 #endif /* CONFIG_SCHED_DEBUG */
5386 static int sd_degenerate(struct sched_domain
*sd
)
5388 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5391 /* Following flags need at least 2 groups */
5392 if (sd
->flags
& (SD_LOAD_BALANCE
|
5393 SD_BALANCE_NEWIDLE
|
5396 SD_SHARE_CPUCAPACITY
|
5397 SD_SHARE_PKG_RESOURCES
|
5398 SD_SHARE_POWERDOMAIN
)) {
5399 if (sd
->groups
!= sd
->groups
->next
)
5403 /* Following flags don't use groups */
5404 if (sd
->flags
& (SD_WAKE_AFFINE
))
5411 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5413 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5415 if (sd_degenerate(parent
))
5418 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5421 /* Flags needing groups don't count if only 1 group in parent */
5422 if (parent
->groups
== parent
->groups
->next
) {
5423 pflags
&= ~(SD_LOAD_BALANCE
|
5424 SD_BALANCE_NEWIDLE
|
5427 SD_SHARE_CPUCAPACITY
|
5428 SD_SHARE_PKG_RESOURCES
|
5430 SD_SHARE_POWERDOMAIN
);
5431 if (nr_node_ids
== 1)
5432 pflags
&= ~SD_SERIALIZE
;
5434 if (~cflags
& pflags
)
5440 static void free_rootdomain(struct rcu_head
*rcu
)
5442 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5444 cpupri_cleanup(&rd
->cpupri
);
5445 cpudl_cleanup(&rd
->cpudl
);
5446 free_cpumask_var(rd
->dlo_mask
);
5447 free_cpumask_var(rd
->rto_mask
);
5448 free_cpumask_var(rd
->online
);
5449 free_cpumask_var(rd
->span
);
5453 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5455 struct root_domain
*old_rd
= NULL
;
5456 unsigned long flags
;
5458 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5463 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5466 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5469 * If we dont want to free the old_rd yet then
5470 * set old_rd to NULL to skip the freeing later
5473 if (!atomic_dec_and_test(&old_rd
->refcount
))
5477 atomic_inc(&rd
->refcount
);
5480 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5481 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5484 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5487 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5490 static int init_rootdomain(struct root_domain
*rd
)
5492 memset(rd
, 0, sizeof(*rd
));
5494 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5496 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5498 if (!alloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
5500 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5503 init_dl_bw(&rd
->dl_bw
);
5504 if (cpudl_init(&rd
->cpudl
) != 0)
5507 if (cpupri_init(&rd
->cpupri
) != 0)
5512 free_cpumask_var(rd
->rto_mask
);
5514 free_cpumask_var(rd
->dlo_mask
);
5516 free_cpumask_var(rd
->online
);
5518 free_cpumask_var(rd
->span
);
5524 * By default the system creates a single root-domain with all cpus as
5525 * members (mimicking the global state we have today).
5527 struct root_domain def_root_domain
;
5529 static void init_defrootdomain(void)
5531 init_rootdomain(&def_root_domain
);
5533 atomic_set(&def_root_domain
.refcount
, 1);
5536 static struct root_domain
*alloc_rootdomain(void)
5538 struct root_domain
*rd
;
5540 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5544 if (init_rootdomain(rd
) != 0) {
5552 static void free_sched_groups(struct sched_group
*sg
, int free_sgc
)
5554 struct sched_group
*tmp
, *first
;
5563 if (free_sgc
&& atomic_dec_and_test(&sg
->sgc
->ref
))
5568 } while (sg
!= first
);
5571 static void free_sched_domain(struct rcu_head
*rcu
)
5573 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5576 * If its an overlapping domain it has private groups, iterate and
5579 if (sd
->flags
& SD_OVERLAP
) {
5580 free_sched_groups(sd
->groups
, 1);
5581 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5582 kfree(sd
->groups
->sgc
);
5588 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5590 call_rcu(&sd
->rcu
, free_sched_domain
);
5593 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5595 for (; sd
; sd
= sd
->parent
)
5596 destroy_sched_domain(sd
, cpu
);
5600 * Keep a special pointer to the highest sched_domain that has
5601 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5602 * allows us to avoid some pointer chasing select_idle_sibling().
5604 * Also keep a unique ID per domain (we use the first cpu number in
5605 * the cpumask of the domain), this allows us to quickly tell if
5606 * two cpus are in the same cache domain, see cpus_share_cache().
5608 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5609 DEFINE_PER_CPU(int, sd_llc_size
);
5610 DEFINE_PER_CPU(int, sd_llc_id
);
5611 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
5612 DEFINE_PER_CPU(struct sched_domain
*, sd_busy
);
5613 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
5615 static void update_top_cache_domain(int cpu
)
5617 struct sched_domain
*sd
;
5618 struct sched_domain
*busy_sd
= NULL
;
5622 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5624 id
= cpumask_first(sched_domain_span(sd
));
5625 size
= cpumask_weight(sched_domain_span(sd
));
5626 busy_sd
= sd
->parent
; /* sd_busy */
5628 rcu_assign_pointer(per_cpu(sd_busy
, cpu
), busy_sd
);
5630 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5631 per_cpu(sd_llc_size
, cpu
) = size
;
5632 per_cpu(sd_llc_id
, cpu
) = id
;
5634 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
5635 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
5637 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
5638 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
5642 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5643 * hold the hotplug lock.
5646 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5648 struct rq
*rq
= cpu_rq(cpu
);
5649 struct sched_domain
*tmp
;
5651 /* Remove the sched domains which do not contribute to scheduling. */
5652 for (tmp
= sd
; tmp
; ) {
5653 struct sched_domain
*parent
= tmp
->parent
;
5657 if (sd_parent_degenerate(tmp
, parent
)) {
5658 tmp
->parent
= parent
->parent
;
5660 parent
->parent
->child
= tmp
;
5662 * Transfer SD_PREFER_SIBLING down in case of a
5663 * degenerate parent; the spans match for this
5664 * so the property transfers.
5666 if (parent
->flags
& SD_PREFER_SIBLING
)
5667 tmp
->flags
|= SD_PREFER_SIBLING
;
5668 destroy_sched_domain(parent
, cpu
);
5673 if (sd
&& sd_degenerate(sd
)) {
5676 destroy_sched_domain(tmp
, cpu
);
5681 sched_domain_debug(sd
, cpu
);
5683 rq_attach_root(rq
, rd
);
5685 rcu_assign_pointer(rq
->sd
, sd
);
5686 destroy_sched_domains(tmp
, cpu
);
5688 update_top_cache_domain(cpu
);
5691 /* cpus with isolated domains */
5692 static cpumask_var_t cpu_isolated_map
;
5694 /* Setup the mask of cpus configured for isolated domains */
5695 static int __init
isolated_cpu_setup(char *str
)
5697 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5698 cpulist_parse(str
, cpu_isolated_map
);
5702 __setup("isolcpus=", isolated_cpu_setup
);
5705 struct sched_domain
** __percpu sd
;
5706 struct root_domain
*rd
;
5717 * Build an iteration mask that can exclude certain CPUs from the upwards
5720 * Asymmetric node setups can result in situations where the domain tree is of
5721 * unequal depth, make sure to skip domains that already cover the entire
5724 * In that case build_sched_domains() will have terminated the iteration early
5725 * and our sibling sd spans will be empty. Domains should always include the
5726 * cpu they're built on, so check that.
5729 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5731 const struct cpumask
*span
= sched_domain_span(sd
);
5732 struct sd_data
*sdd
= sd
->private;
5733 struct sched_domain
*sibling
;
5736 for_each_cpu(i
, span
) {
5737 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5738 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5741 cpumask_set_cpu(i
, sched_group_mask(sg
));
5746 * Return the canonical balance cpu for this group, this is the first cpu
5747 * of this group that's also in the iteration mask.
5749 int group_balance_cpu(struct sched_group
*sg
)
5751 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5755 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5757 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5758 const struct cpumask
*span
= sched_domain_span(sd
);
5759 struct cpumask
*covered
= sched_domains_tmpmask
;
5760 struct sd_data
*sdd
= sd
->private;
5761 struct sched_domain
*child
;
5764 cpumask_clear(covered
);
5766 for_each_cpu(i
, span
) {
5767 struct cpumask
*sg_span
;
5769 if (cpumask_test_cpu(i
, covered
))
5772 child
= *per_cpu_ptr(sdd
->sd
, i
);
5774 /* See the comment near build_group_mask(). */
5775 if (!cpumask_test_cpu(i
, sched_domain_span(child
)))
5778 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5779 GFP_KERNEL
, cpu_to_node(cpu
));
5784 sg_span
= sched_group_cpus(sg
);
5786 child
= child
->child
;
5787 cpumask_copy(sg_span
, sched_domain_span(child
));
5789 cpumask_set_cpu(i
, sg_span
);
5791 cpumask_or(covered
, covered
, sg_span
);
5793 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, i
);
5794 if (atomic_inc_return(&sg
->sgc
->ref
) == 1)
5795 build_group_mask(sd
, sg
);
5798 * Initialize sgc->capacity such that even if we mess up the
5799 * domains and no possible iteration will get us here, we won't
5802 sg
->sgc
->capacity
= SCHED_CAPACITY_SCALE
* cpumask_weight(sg_span
);
5803 sg
->sgc
->capacity_orig
= sg
->sgc
->capacity
;
5806 * Make sure the first group of this domain contains the
5807 * canonical balance cpu. Otherwise the sched_domain iteration
5808 * breaks. See update_sg_lb_stats().
5810 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5811 group_balance_cpu(sg
) == cpu
)
5821 sd
->groups
= groups
;
5826 free_sched_groups(first
, 0);
5831 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5833 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5834 struct sched_domain
*child
= sd
->child
;
5837 cpu
= cpumask_first(sched_domain_span(child
));
5840 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5841 (*sg
)->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
5842 atomic_set(&(*sg
)->sgc
->ref
, 1); /* for claim_allocations */
5849 * build_sched_groups will build a circular linked list of the groups
5850 * covered by the given span, and will set each group's ->cpumask correctly,
5851 * and ->cpu_capacity to 0.
5853 * Assumes the sched_domain tree is fully constructed
5856 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5858 struct sched_group
*first
= NULL
, *last
= NULL
;
5859 struct sd_data
*sdd
= sd
->private;
5860 const struct cpumask
*span
= sched_domain_span(sd
);
5861 struct cpumask
*covered
;
5864 get_group(cpu
, sdd
, &sd
->groups
);
5865 atomic_inc(&sd
->groups
->ref
);
5867 if (cpu
!= cpumask_first(span
))
5870 lockdep_assert_held(&sched_domains_mutex
);
5871 covered
= sched_domains_tmpmask
;
5873 cpumask_clear(covered
);
5875 for_each_cpu(i
, span
) {
5876 struct sched_group
*sg
;
5879 if (cpumask_test_cpu(i
, covered
))
5882 group
= get_group(i
, sdd
, &sg
);
5883 cpumask_setall(sched_group_mask(sg
));
5885 for_each_cpu(j
, span
) {
5886 if (get_group(j
, sdd
, NULL
) != group
)
5889 cpumask_set_cpu(j
, covered
);
5890 cpumask_set_cpu(j
, sched_group_cpus(sg
));
5905 * Initialize sched groups cpu_capacity.
5907 * cpu_capacity indicates the capacity of sched group, which is used while
5908 * distributing the load between different sched groups in a sched domain.
5909 * Typically cpu_capacity for all the groups in a sched domain will be same
5910 * unless there are asymmetries in the topology. If there are asymmetries,
5911 * group having more cpu_capacity will pickup more load compared to the
5912 * group having less cpu_capacity.
5914 static void init_sched_groups_capacity(int cpu
, struct sched_domain
*sd
)
5916 struct sched_group
*sg
= sd
->groups
;
5921 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
5923 } while (sg
!= sd
->groups
);
5925 if (cpu
!= group_balance_cpu(sg
))
5928 update_group_capacity(sd
, cpu
);
5929 atomic_set(&sg
->sgc
->nr_busy_cpus
, sg
->group_weight
);
5933 * Initializers for schedule domains
5934 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5937 static int default_relax_domain_level
= -1;
5938 int sched_domain_level_max
;
5940 static int __init
setup_relax_domain_level(char *str
)
5942 if (kstrtoint(str
, 0, &default_relax_domain_level
))
5943 pr_warn("Unable to set relax_domain_level\n");
5947 __setup("relax_domain_level=", setup_relax_domain_level
);
5949 static void set_domain_attribute(struct sched_domain
*sd
,
5950 struct sched_domain_attr
*attr
)
5954 if (!attr
|| attr
->relax_domain_level
< 0) {
5955 if (default_relax_domain_level
< 0)
5958 request
= default_relax_domain_level
;
5960 request
= attr
->relax_domain_level
;
5961 if (request
< sd
->level
) {
5962 /* turn off idle balance on this domain */
5963 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5965 /* turn on idle balance on this domain */
5966 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5970 static void __sdt_free(const struct cpumask
*cpu_map
);
5971 static int __sdt_alloc(const struct cpumask
*cpu_map
);
5973 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
5974 const struct cpumask
*cpu_map
)
5978 if (!atomic_read(&d
->rd
->refcount
))
5979 free_rootdomain(&d
->rd
->rcu
); /* fall through */
5981 free_percpu(d
->sd
); /* fall through */
5983 __sdt_free(cpu_map
); /* fall through */
5989 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
5990 const struct cpumask
*cpu_map
)
5992 memset(d
, 0, sizeof(*d
));
5994 if (__sdt_alloc(cpu_map
))
5995 return sa_sd_storage
;
5996 d
->sd
= alloc_percpu(struct sched_domain
*);
5998 return sa_sd_storage
;
5999 d
->rd
= alloc_rootdomain();
6002 return sa_rootdomain
;
6006 * NULL the sd_data elements we've used to build the sched_domain and
6007 * sched_group structure so that the subsequent __free_domain_allocs()
6008 * will not free the data we're using.
6010 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
6012 struct sd_data
*sdd
= sd
->private;
6014 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
6015 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
6017 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
6018 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
6020 if (atomic_read(&(*per_cpu_ptr(sdd
->sgc
, cpu
))->ref
))
6021 *per_cpu_ptr(sdd
->sgc
, cpu
) = NULL
;
6025 static int sched_domains_numa_levels
;
6026 static int *sched_domains_numa_distance
;
6027 static struct cpumask
***sched_domains_numa_masks
;
6028 static int sched_domains_curr_level
;
6032 * SD_flags allowed in topology descriptions.
6034 * SD_SHARE_CPUCAPACITY - describes SMT topologies
6035 * SD_SHARE_PKG_RESOURCES - describes shared caches
6036 * SD_NUMA - describes NUMA topologies
6037 * SD_SHARE_POWERDOMAIN - describes shared power domain
6040 * SD_ASYM_PACKING - describes SMT quirks
6042 #define TOPOLOGY_SD_FLAGS \
6043 (SD_SHARE_CPUCAPACITY | \
6044 SD_SHARE_PKG_RESOURCES | \
6047 SD_SHARE_POWERDOMAIN)
6049 static struct sched_domain
*
6050 sd_init(struct sched_domain_topology_level
*tl
, int cpu
)
6052 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
6053 int sd_weight
, sd_flags
= 0;
6057 * Ugly hack to pass state to sd_numa_mask()...
6059 sched_domains_curr_level
= tl
->numa_level
;
6062 sd_weight
= cpumask_weight(tl
->mask(cpu
));
6065 sd_flags
= (*tl
->sd_flags
)();
6066 if (WARN_ONCE(sd_flags
& ~TOPOLOGY_SD_FLAGS
,
6067 "wrong sd_flags in topology description\n"))
6068 sd_flags
&= ~TOPOLOGY_SD_FLAGS
;
6070 *sd
= (struct sched_domain
){
6071 .min_interval
= sd_weight
,
6072 .max_interval
= 2*sd_weight
,
6074 .imbalance_pct
= 125,
6076 .cache_nice_tries
= 0,
6083 .flags
= 1*SD_LOAD_BALANCE
6084 | 1*SD_BALANCE_NEWIDLE
6089 | 0*SD_SHARE_CPUCAPACITY
6090 | 0*SD_SHARE_PKG_RESOURCES
6092 | 0*SD_PREFER_SIBLING
6097 .last_balance
= jiffies
,
6098 .balance_interval
= sd_weight
,
6100 .max_newidle_lb_cost
= 0,
6101 .next_decay_max_lb_cost
= jiffies
,
6102 #ifdef CONFIG_SCHED_DEBUG
6108 * Convert topological properties into behaviour.
6111 if (sd
->flags
& SD_SHARE_CPUCAPACITY
) {
6112 sd
->imbalance_pct
= 110;
6113 sd
->smt_gain
= 1178; /* ~15% */
6115 } else if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
6116 sd
->imbalance_pct
= 117;
6117 sd
->cache_nice_tries
= 1;
6121 } else if (sd
->flags
& SD_NUMA
) {
6122 sd
->cache_nice_tries
= 2;
6126 sd
->flags
|= SD_SERIALIZE
;
6127 if (sched_domains_numa_distance
[tl
->numa_level
] > RECLAIM_DISTANCE
) {
6128 sd
->flags
&= ~(SD_BALANCE_EXEC
|
6135 sd
->flags
|= SD_PREFER_SIBLING
;
6136 sd
->cache_nice_tries
= 1;
6141 sd
->private = &tl
->data
;
6147 * Topology list, bottom-up.
6149 static struct sched_domain_topology_level default_topology
[] = {
6150 #ifdef CONFIG_SCHED_SMT
6151 { cpu_smt_mask
, cpu_smt_flags
, SD_INIT_NAME(SMT
) },
6153 #ifdef CONFIG_SCHED_MC
6154 { cpu_coregroup_mask
, cpu_core_flags
, SD_INIT_NAME(MC
) },
6156 { cpu_cpu_mask
, SD_INIT_NAME(DIE
) },
6160 struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6162 #define for_each_sd_topology(tl) \
6163 for (tl = sched_domain_topology; tl->mask; tl++)
6165 void set_sched_topology(struct sched_domain_topology_level
*tl
)
6167 sched_domain_topology
= tl
;
6172 static const struct cpumask
*sd_numa_mask(int cpu
)
6174 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6177 static void sched_numa_warn(const char *str
)
6179 static int done
= false;
6187 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6189 for (i
= 0; i
< nr_node_ids
; i
++) {
6190 printk(KERN_WARNING
" ");
6191 for (j
= 0; j
< nr_node_ids
; j
++)
6192 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6193 printk(KERN_CONT
"\n");
6195 printk(KERN_WARNING
"\n");
6198 static bool find_numa_distance(int distance
)
6202 if (distance
== node_distance(0, 0))
6205 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6206 if (sched_domains_numa_distance
[i
] == distance
)
6213 static void sched_init_numa(void)
6215 int next_distance
, curr_distance
= node_distance(0, 0);
6216 struct sched_domain_topology_level
*tl
;
6220 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6221 if (!sched_domains_numa_distance
)
6225 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6226 * unique distances in the node_distance() table.
6228 * Assumes node_distance(0,j) includes all distances in
6229 * node_distance(i,j) in order to avoid cubic time.
6231 next_distance
= curr_distance
;
6232 for (i
= 0; i
< nr_node_ids
; i
++) {
6233 for (j
= 0; j
< nr_node_ids
; j
++) {
6234 for (k
= 0; k
< nr_node_ids
; k
++) {
6235 int distance
= node_distance(i
, k
);
6237 if (distance
> curr_distance
&&
6238 (distance
< next_distance
||
6239 next_distance
== curr_distance
))
6240 next_distance
= distance
;
6243 * While not a strong assumption it would be nice to know
6244 * about cases where if node A is connected to B, B is not
6245 * equally connected to A.
6247 if (sched_debug() && node_distance(k
, i
) != distance
)
6248 sched_numa_warn("Node-distance not symmetric");
6250 if (sched_debug() && i
&& !find_numa_distance(distance
))
6251 sched_numa_warn("Node-0 not representative");
6253 if (next_distance
!= curr_distance
) {
6254 sched_domains_numa_distance
[level
++] = next_distance
;
6255 sched_domains_numa_levels
= level
;
6256 curr_distance
= next_distance
;
6261 * In case of sched_debug() we verify the above assumption.
6267 * 'level' contains the number of unique distances, excluding the
6268 * identity distance node_distance(i,i).
6270 * The sched_domains_numa_distance[] array includes the actual distance
6275 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6276 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6277 * the array will contain less then 'level' members. This could be
6278 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6279 * in other functions.
6281 * We reset it to 'level' at the end of this function.
6283 sched_domains_numa_levels
= 0;
6285 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6286 if (!sched_domains_numa_masks
)
6290 * Now for each level, construct a mask per node which contains all
6291 * cpus of nodes that are that many hops away from us.
6293 for (i
= 0; i
< level
; i
++) {
6294 sched_domains_numa_masks
[i
] =
6295 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6296 if (!sched_domains_numa_masks
[i
])
6299 for (j
= 0; j
< nr_node_ids
; j
++) {
6300 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6304 sched_domains_numa_masks
[i
][j
] = mask
;
6306 for (k
= 0; k
< nr_node_ids
; k
++) {
6307 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6310 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6315 /* Compute default topology size */
6316 for (i
= 0; sched_domain_topology
[i
].mask
; i
++);
6318 tl
= kzalloc((i
+ level
+ 1) *
6319 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6324 * Copy the default topology bits..
6326 for (i
= 0; sched_domain_topology
[i
].mask
; i
++)
6327 tl
[i
] = sched_domain_topology
[i
];
6330 * .. and append 'j' levels of NUMA goodness.
6332 for (j
= 0; j
< level
; i
++, j
++) {
6333 tl
[i
] = (struct sched_domain_topology_level
){
6334 .mask
= sd_numa_mask
,
6335 .sd_flags
= cpu_numa_flags
,
6336 .flags
= SDTL_OVERLAP
,
6342 sched_domain_topology
= tl
;
6344 sched_domains_numa_levels
= level
;
6347 static void sched_domains_numa_masks_set(int cpu
)
6350 int node
= cpu_to_node(cpu
);
6352 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6353 for (j
= 0; j
< nr_node_ids
; j
++) {
6354 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6355 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6360 static void sched_domains_numa_masks_clear(int cpu
)
6363 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6364 for (j
= 0; j
< nr_node_ids
; j
++)
6365 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6370 * Update sched_domains_numa_masks[level][node] array when new cpus
6373 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6374 unsigned long action
,
6377 int cpu
= (long)hcpu
;
6379 switch (action
& ~CPU_TASKS_FROZEN
) {
6381 sched_domains_numa_masks_set(cpu
);
6385 sched_domains_numa_masks_clear(cpu
);
6395 static inline void sched_init_numa(void)
6399 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6400 unsigned long action
,
6405 #endif /* CONFIG_NUMA */
6407 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6409 struct sched_domain_topology_level
*tl
;
6412 for_each_sd_topology(tl
) {
6413 struct sd_data
*sdd
= &tl
->data
;
6415 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6419 sdd
->sg
= alloc_percpu(struct sched_group
*);
6423 sdd
->sgc
= alloc_percpu(struct sched_group_capacity
*);
6427 for_each_cpu(j
, cpu_map
) {
6428 struct sched_domain
*sd
;
6429 struct sched_group
*sg
;
6430 struct sched_group_capacity
*sgc
;
6432 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6433 GFP_KERNEL
, cpu_to_node(j
));
6437 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6439 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6440 GFP_KERNEL
, cpu_to_node(j
));
6446 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6448 sgc
= kzalloc_node(sizeof(struct sched_group_capacity
) + cpumask_size(),
6449 GFP_KERNEL
, cpu_to_node(j
));
6453 *per_cpu_ptr(sdd
->sgc
, j
) = sgc
;
6460 static void __sdt_free(const struct cpumask
*cpu_map
)
6462 struct sched_domain_topology_level
*tl
;
6465 for_each_sd_topology(tl
) {
6466 struct sd_data
*sdd
= &tl
->data
;
6468 for_each_cpu(j
, cpu_map
) {
6469 struct sched_domain
*sd
;
6472 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6473 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6474 free_sched_groups(sd
->groups
, 0);
6475 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6479 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6481 kfree(*per_cpu_ptr(sdd
->sgc
, j
));
6483 free_percpu(sdd
->sd
);
6485 free_percpu(sdd
->sg
);
6487 free_percpu(sdd
->sgc
);
6492 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6493 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6494 struct sched_domain
*child
, int cpu
)
6496 struct sched_domain
*sd
= sd_init(tl
, cpu
);
6500 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6502 sd
->level
= child
->level
+ 1;
6503 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6507 if (!cpumask_subset(sched_domain_span(child
),
6508 sched_domain_span(sd
))) {
6509 pr_err("BUG: arch topology borken\n");
6510 #ifdef CONFIG_SCHED_DEBUG
6511 pr_err(" the %s domain not a subset of the %s domain\n",
6512 child
->name
, sd
->name
);
6514 /* Fixup, ensure @sd has at least @child cpus. */
6515 cpumask_or(sched_domain_span(sd
),
6516 sched_domain_span(sd
),
6517 sched_domain_span(child
));
6521 set_domain_attribute(sd
, attr
);
6527 * Build sched domains for a given set of cpus and attach the sched domains
6528 * to the individual cpus
6530 static int build_sched_domains(const struct cpumask
*cpu_map
,
6531 struct sched_domain_attr
*attr
)
6533 enum s_alloc alloc_state
;
6534 struct sched_domain
*sd
;
6536 int i
, ret
= -ENOMEM
;
6538 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6539 if (alloc_state
!= sa_rootdomain
)
6542 /* Set up domains for cpus specified by the cpu_map. */
6543 for_each_cpu(i
, cpu_map
) {
6544 struct sched_domain_topology_level
*tl
;
6547 for_each_sd_topology(tl
) {
6548 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6549 if (tl
== sched_domain_topology
)
6550 *per_cpu_ptr(d
.sd
, i
) = sd
;
6551 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6552 sd
->flags
|= SD_OVERLAP
;
6553 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6558 /* Build the groups for the domains */
6559 for_each_cpu(i
, cpu_map
) {
6560 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6561 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6562 if (sd
->flags
& SD_OVERLAP
) {
6563 if (build_overlap_sched_groups(sd
, i
))
6566 if (build_sched_groups(sd
, i
))
6572 /* Calculate CPU capacity for physical packages and nodes */
6573 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6574 if (!cpumask_test_cpu(i
, cpu_map
))
6577 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6578 claim_allocations(i
, sd
);
6579 init_sched_groups_capacity(i
, sd
);
6583 /* Attach the domains */
6585 for_each_cpu(i
, cpu_map
) {
6586 sd
= *per_cpu_ptr(d
.sd
, i
);
6587 cpu_attach_domain(sd
, d
.rd
, i
);
6593 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6597 static cpumask_var_t
*doms_cur
; /* current sched domains */
6598 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6599 static struct sched_domain_attr
*dattr_cur
;
6600 /* attribues of custom domains in 'doms_cur' */
6603 * Special case: If a kmalloc of a doms_cur partition (array of
6604 * cpumask) fails, then fallback to a single sched domain,
6605 * as determined by the single cpumask fallback_doms.
6607 static cpumask_var_t fallback_doms
;
6610 * arch_update_cpu_topology lets virtualized architectures update the
6611 * cpu core maps. It is supposed to return 1 if the topology changed
6612 * or 0 if it stayed the same.
6614 int __weak
arch_update_cpu_topology(void)
6619 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6622 cpumask_var_t
*doms
;
6624 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6627 for (i
= 0; i
< ndoms
; i
++) {
6628 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6629 free_sched_domains(doms
, i
);
6636 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6639 for (i
= 0; i
< ndoms
; i
++)
6640 free_cpumask_var(doms
[i
]);
6645 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6646 * For now this just excludes isolated cpus, but could be used to
6647 * exclude other special cases in the future.
6649 static int init_sched_domains(const struct cpumask
*cpu_map
)
6653 arch_update_cpu_topology();
6655 doms_cur
= alloc_sched_domains(ndoms_cur
);
6657 doms_cur
= &fallback_doms
;
6658 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6659 err
= build_sched_domains(doms_cur
[0], NULL
);
6660 register_sched_domain_sysctl();
6666 * Detach sched domains from a group of cpus specified in cpu_map
6667 * These cpus will now be attached to the NULL domain
6669 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6674 for_each_cpu(i
, cpu_map
)
6675 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6679 /* handle null as "default" */
6680 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6681 struct sched_domain_attr
*new, int idx_new
)
6683 struct sched_domain_attr tmp
;
6690 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6691 new ? (new + idx_new
) : &tmp
,
6692 sizeof(struct sched_domain_attr
));
6696 * Partition sched domains as specified by the 'ndoms_new'
6697 * cpumasks in the array doms_new[] of cpumasks. This compares
6698 * doms_new[] to the current sched domain partitioning, doms_cur[].
6699 * It destroys each deleted domain and builds each new domain.
6701 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6702 * The masks don't intersect (don't overlap.) We should setup one
6703 * sched domain for each mask. CPUs not in any of the cpumasks will
6704 * not be load balanced. If the same cpumask appears both in the
6705 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6708 * The passed in 'doms_new' should be allocated using
6709 * alloc_sched_domains. This routine takes ownership of it and will
6710 * free_sched_domains it when done with it. If the caller failed the
6711 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6712 * and partition_sched_domains() will fallback to the single partition
6713 * 'fallback_doms', it also forces the domains to be rebuilt.
6715 * If doms_new == NULL it will be replaced with cpu_online_mask.
6716 * ndoms_new == 0 is a special case for destroying existing domains,
6717 * and it will not create the default domain.
6719 * Call with hotplug lock held
6721 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6722 struct sched_domain_attr
*dattr_new
)
6727 mutex_lock(&sched_domains_mutex
);
6729 /* always unregister in case we don't destroy any domains */
6730 unregister_sched_domain_sysctl();
6732 /* Let architecture update cpu core mappings. */
6733 new_topology
= arch_update_cpu_topology();
6735 n
= doms_new
? ndoms_new
: 0;
6737 /* Destroy deleted domains */
6738 for (i
= 0; i
< ndoms_cur
; i
++) {
6739 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6740 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6741 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6744 /* no match - a current sched domain not in new doms_new[] */
6745 detach_destroy_domains(doms_cur
[i
]);
6751 if (doms_new
== NULL
) {
6753 doms_new
= &fallback_doms
;
6754 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6755 WARN_ON_ONCE(dattr_new
);
6758 /* Build new domains */
6759 for (i
= 0; i
< ndoms_new
; i
++) {
6760 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6761 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6762 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6765 /* no match - add a new doms_new */
6766 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6771 /* Remember the new sched domains */
6772 if (doms_cur
!= &fallback_doms
)
6773 free_sched_domains(doms_cur
, ndoms_cur
);
6774 kfree(dattr_cur
); /* kfree(NULL) is safe */
6775 doms_cur
= doms_new
;
6776 dattr_cur
= dattr_new
;
6777 ndoms_cur
= ndoms_new
;
6779 register_sched_domain_sysctl();
6781 mutex_unlock(&sched_domains_mutex
);
6784 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6787 * Update cpusets according to cpu_active mask. If cpusets are
6788 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6789 * around partition_sched_domains().
6791 * If we come here as part of a suspend/resume, don't touch cpusets because we
6792 * want to restore it back to its original state upon resume anyway.
6794 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6798 case CPU_ONLINE_FROZEN
:
6799 case CPU_DOWN_FAILED_FROZEN
:
6802 * num_cpus_frozen tracks how many CPUs are involved in suspend
6803 * resume sequence. As long as this is not the last online
6804 * operation in the resume sequence, just build a single sched
6805 * domain, ignoring cpusets.
6808 if (likely(num_cpus_frozen
)) {
6809 partition_sched_domains(1, NULL
, NULL
);
6814 * This is the last CPU online operation. So fall through and
6815 * restore the original sched domains by considering the
6816 * cpuset configurations.
6820 case CPU_DOWN_FAILED
:
6821 cpuset_update_active_cpus(true);
6829 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6833 case CPU_DOWN_PREPARE
:
6834 cpuset_update_active_cpus(false);
6836 case CPU_DOWN_PREPARE_FROZEN
:
6838 partition_sched_domains(1, NULL
, NULL
);
6846 void __init
sched_init_smp(void)
6848 cpumask_var_t non_isolated_cpus
;
6850 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6851 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6856 * There's no userspace yet to cause hotplug operations; hence all the
6857 * cpu masks are stable and all blatant races in the below code cannot
6860 mutex_lock(&sched_domains_mutex
);
6861 init_sched_domains(cpu_active_mask
);
6862 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6863 if (cpumask_empty(non_isolated_cpus
))
6864 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6865 mutex_unlock(&sched_domains_mutex
);
6867 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
6868 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6869 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6873 /* Move init over to a non-isolated CPU */
6874 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6876 sched_init_granularity();
6877 free_cpumask_var(non_isolated_cpus
);
6879 init_sched_rt_class();
6880 init_sched_dl_class();
6883 void __init
sched_init_smp(void)
6885 sched_init_granularity();
6887 #endif /* CONFIG_SMP */
6889 const_debug
unsigned int sysctl_timer_migration
= 1;
6891 int in_sched_functions(unsigned long addr
)
6893 return in_lock_functions(addr
) ||
6894 (addr
>= (unsigned long)__sched_text_start
6895 && addr
< (unsigned long)__sched_text_end
);
6898 #ifdef CONFIG_CGROUP_SCHED
6900 * Default task group.
6901 * Every task in system belongs to this group at bootup.
6903 struct task_group root_task_group
;
6904 LIST_HEAD(task_groups
);
6907 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
6909 void __init
sched_init(void)
6912 unsigned long alloc_size
= 0, ptr
;
6914 #ifdef CONFIG_FAIR_GROUP_SCHED
6915 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6917 #ifdef CONFIG_RT_GROUP_SCHED
6918 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6920 #ifdef CONFIG_CPUMASK_OFFSTACK
6921 alloc_size
+= num_possible_cpus() * cpumask_size();
6924 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6926 #ifdef CONFIG_FAIR_GROUP_SCHED
6927 root_task_group
.se
= (struct sched_entity
**)ptr
;
6928 ptr
+= nr_cpu_ids
* sizeof(void **);
6930 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6931 ptr
+= nr_cpu_ids
* sizeof(void **);
6933 #endif /* CONFIG_FAIR_GROUP_SCHED */
6934 #ifdef CONFIG_RT_GROUP_SCHED
6935 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6936 ptr
+= nr_cpu_ids
* sizeof(void **);
6938 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6939 ptr
+= nr_cpu_ids
* sizeof(void **);
6941 #endif /* CONFIG_RT_GROUP_SCHED */
6942 #ifdef CONFIG_CPUMASK_OFFSTACK
6943 for_each_possible_cpu(i
) {
6944 per_cpu(load_balance_mask
, i
) = (void *)ptr
;
6945 ptr
+= cpumask_size();
6947 #endif /* CONFIG_CPUMASK_OFFSTACK */
6950 init_rt_bandwidth(&def_rt_bandwidth
,
6951 global_rt_period(), global_rt_runtime());
6952 init_dl_bandwidth(&def_dl_bandwidth
,
6953 global_rt_period(), global_rt_runtime());
6956 init_defrootdomain();
6959 #ifdef CONFIG_RT_GROUP_SCHED
6960 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6961 global_rt_period(), global_rt_runtime());
6962 #endif /* CONFIG_RT_GROUP_SCHED */
6964 #ifdef CONFIG_CGROUP_SCHED
6965 list_add(&root_task_group
.list
, &task_groups
);
6966 INIT_LIST_HEAD(&root_task_group
.children
);
6967 INIT_LIST_HEAD(&root_task_group
.siblings
);
6968 autogroup_init(&init_task
);
6970 #endif /* CONFIG_CGROUP_SCHED */
6972 for_each_possible_cpu(i
) {
6976 raw_spin_lock_init(&rq
->lock
);
6978 rq
->calc_load_active
= 0;
6979 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6980 init_cfs_rq(&rq
->cfs
);
6981 init_rt_rq(&rq
->rt
, rq
);
6982 init_dl_rq(&rq
->dl
, rq
);
6983 #ifdef CONFIG_FAIR_GROUP_SCHED
6984 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6985 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6987 * How much cpu bandwidth does root_task_group get?
6989 * In case of task-groups formed thr' the cgroup filesystem, it
6990 * gets 100% of the cpu resources in the system. This overall
6991 * system cpu resource is divided among the tasks of
6992 * root_task_group and its child task-groups in a fair manner,
6993 * based on each entity's (task or task-group's) weight
6994 * (se->load.weight).
6996 * In other words, if root_task_group has 10 tasks of weight
6997 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6998 * then A0's share of the cpu resource is:
7000 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7002 * We achieve this by letting root_task_group's tasks sit
7003 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7005 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
7006 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
7007 #endif /* CONFIG_FAIR_GROUP_SCHED */
7009 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7010 #ifdef CONFIG_RT_GROUP_SCHED
7011 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
7014 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7015 rq
->cpu_load
[j
] = 0;
7017 rq
->last_load_update_tick
= jiffies
;
7022 rq
->cpu_capacity
= SCHED_CAPACITY_SCALE
;
7023 rq
->post_schedule
= 0;
7024 rq
->active_balance
= 0;
7025 rq
->next_balance
= jiffies
;
7030 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7031 rq
->max_idle_balance_cost
= sysctl_sched_migration_cost
;
7033 INIT_LIST_HEAD(&rq
->cfs_tasks
);
7035 rq_attach_root(rq
, &def_root_domain
);
7036 #ifdef CONFIG_NO_HZ_COMMON
7039 #ifdef CONFIG_NO_HZ_FULL
7040 rq
->last_sched_tick
= 0;
7044 atomic_set(&rq
->nr_iowait
, 0);
7047 set_load_weight(&init_task
);
7049 #ifdef CONFIG_PREEMPT_NOTIFIERS
7050 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7054 * The boot idle thread does lazy MMU switching as well:
7056 atomic_inc(&init_mm
.mm_count
);
7057 enter_lazy_tlb(&init_mm
, current
);
7060 * Make us the idle thread. Technically, schedule() should not be
7061 * called from this thread, however somewhere below it might be,
7062 * but because we are the idle thread, we just pick up running again
7063 * when this runqueue becomes "idle".
7065 init_idle(current
, smp_processor_id());
7067 calc_load_update
= jiffies
+ LOAD_FREQ
;
7070 * During early bootup we pretend to be a normal task:
7072 current
->sched_class
= &fair_sched_class
;
7075 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
7076 /* May be allocated at isolcpus cmdline parse time */
7077 if (cpu_isolated_map
== NULL
)
7078 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7079 idle_thread_set_boot_cpu();
7080 set_cpu_rq_start_time();
7082 init_sched_fair_class();
7084 scheduler_running
= 1;
7087 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7088 static inline int preempt_count_equals(int preempt_offset
)
7090 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7092 return (nested
== preempt_offset
);
7095 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7097 static unsigned long prev_jiffy
; /* ratelimiting */
7099 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7100 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled() &&
7101 !is_idle_task(current
)) ||
7102 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7104 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7106 prev_jiffy
= jiffies
;
7109 "BUG: sleeping function called from invalid context at %s:%d\n",
7112 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7113 in_atomic(), irqs_disabled(),
7114 current
->pid
, current
->comm
);
7116 debug_show_held_locks(current
);
7117 if (irqs_disabled())
7118 print_irqtrace_events(current
);
7119 #ifdef CONFIG_DEBUG_PREEMPT
7120 if (!preempt_count_equals(preempt_offset
)) {
7121 pr_err("Preemption disabled at:");
7122 print_ip_sym(current
->preempt_disable_ip
);
7128 EXPORT_SYMBOL(__might_sleep
);
7131 #ifdef CONFIG_MAGIC_SYSRQ
7132 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7134 const struct sched_class
*prev_class
= p
->sched_class
;
7135 struct sched_attr attr
= {
7136 .sched_policy
= SCHED_NORMAL
,
7138 int old_prio
= p
->prio
;
7143 dequeue_task(rq
, p
, 0);
7144 __setscheduler(rq
, p
, &attr
);
7146 enqueue_task(rq
, p
, 0);
7150 check_class_changed(rq
, p
, prev_class
, old_prio
);
7153 void normalize_rt_tasks(void)
7155 struct task_struct
*g
, *p
;
7156 unsigned long flags
;
7159 read_lock_irqsave(&tasklist_lock
, flags
);
7160 do_each_thread(g
, p
) {
7162 * Only normalize user tasks:
7167 p
->se
.exec_start
= 0;
7168 #ifdef CONFIG_SCHEDSTATS
7169 p
->se
.statistics
.wait_start
= 0;
7170 p
->se
.statistics
.sleep_start
= 0;
7171 p
->se
.statistics
.block_start
= 0;
7174 if (!dl_task(p
) && !rt_task(p
)) {
7176 * Renice negative nice level userspace
7179 if (task_nice(p
) < 0 && p
->mm
)
7180 set_user_nice(p
, 0);
7184 raw_spin_lock(&p
->pi_lock
);
7185 rq
= __task_rq_lock(p
);
7187 normalize_task(rq
, p
);
7189 __task_rq_unlock(rq
);
7190 raw_spin_unlock(&p
->pi_lock
);
7191 } while_each_thread(g
, p
);
7193 read_unlock_irqrestore(&tasklist_lock
, flags
);
7196 #endif /* CONFIG_MAGIC_SYSRQ */
7198 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7200 * These functions are only useful for the IA64 MCA handling, or kdb.
7202 * They can only be called when the whole system has been
7203 * stopped - every CPU needs to be quiescent, and no scheduling
7204 * activity can take place. Using them for anything else would
7205 * be a serious bug, and as a result, they aren't even visible
7206 * under any other configuration.
7210 * curr_task - return the current task for a given cpu.
7211 * @cpu: the processor in question.
7213 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7215 * Return: The current task for @cpu.
7217 struct task_struct
*curr_task(int cpu
)
7219 return cpu_curr(cpu
);
7222 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7226 * set_curr_task - set the current task for a given cpu.
7227 * @cpu: the processor in question.
7228 * @p: the task pointer to set.
7230 * Description: This function must only be used when non-maskable interrupts
7231 * are serviced on a separate stack. It allows the architecture to switch the
7232 * notion of the current task on a cpu in a non-blocking manner. This function
7233 * must be called with all CPU's synchronized, and interrupts disabled, the
7234 * and caller must save the original value of the current task (see
7235 * curr_task() above) and restore that value before reenabling interrupts and
7236 * re-starting the system.
7238 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7240 void set_curr_task(int cpu
, struct task_struct
*p
)
7247 #ifdef CONFIG_CGROUP_SCHED
7248 /* task_group_lock serializes the addition/removal of task groups */
7249 static DEFINE_SPINLOCK(task_group_lock
);
7251 static void free_sched_group(struct task_group
*tg
)
7253 free_fair_sched_group(tg
);
7254 free_rt_sched_group(tg
);
7259 /* allocate runqueue etc for a new task group */
7260 struct task_group
*sched_create_group(struct task_group
*parent
)
7262 struct task_group
*tg
;
7264 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7266 return ERR_PTR(-ENOMEM
);
7268 if (!alloc_fair_sched_group(tg
, parent
))
7271 if (!alloc_rt_sched_group(tg
, parent
))
7277 free_sched_group(tg
);
7278 return ERR_PTR(-ENOMEM
);
7281 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
7283 unsigned long flags
;
7285 spin_lock_irqsave(&task_group_lock
, flags
);
7286 list_add_rcu(&tg
->list
, &task_groups
);
7288 WARN_ON(!parent
); /* root should already exist */
7290 tg
->parent
= parent
;
7291 INIT_LIST_HEAD(&tg
->children
);
7292 list_add_rcu(&tg
->siblings
, &parent
->children
);
7293 spin_unlock_irqrestore(&task_group_lock
, flags
);
7296 /* rcu callback to free various structures associated with a task group */
7297 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7299 /* now it should be safe to free those cfs_rqs */
7300 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7303 /* Destroy runqueue etc associated with a task group */
7304 void sched_destroy_group(struct task_group
*tg
)
7306 /* wait for possible concurrent references to cfs_rqs complete */
7307 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7310 void sched_offline_group(struct task_group
*tg
)
7312 unsigned long flags
;
7315 /* end participation in shares distribution */
7316 for_each_possible_cpu(i
)
7317 unregister_fair_sched_group(tg
, i
);
7319 spin_lock_irqsave(&task_group_lock
, flags
);
7320 list_del_rcu(&tg
->list
);
7321 list_del_rcu(&tg
->siblings
);
7322 spin_unlock_irqrestore(&task_group_lock
, flags
);
7325 /* change task's runqueue when it moves between groups.
7326 * The caller of this function should have put the task in its new group
7327 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7328 * reflect its new group.
7330 void sched_move_task(struct task_struct
*tsk
)
7332 struct task_group
*tg
;
7334 unsigned long flags
;
7337 rq
= task_rq_lock(tsk
, &flags
);
7339 running
= task_current(rq
, tsk
);
7343 dequeue_task(rq
, tsk
, 0);
7344 if (unlikely(running
))
7345 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7347 tg
= container_of(task_css_check(tsk
, cpu_cgrp_id
,
7348 lockdep_is_held(&tsk
->sighand
->siglock
)),
7349 struct task_group
, css
);
7350 tg
= autogroup_task_group(tsk
, tg
);
7351 tsk
->sched_task_group
= tg
;
7353 #ifdef CONFIG_FAIR_GROUP_SCHED
7354 if (tsk
->sched_class
->task_move_group
)
7355 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
7358 set_task_rq(tsk
, task_cpu(tsk
));
7360 if (unlikely(running
))
7361 tsk
->sched_class
->set_curr_task(rq
);
7363 enqueue_task(rq
, tsk
, 0);
7365 task_rq_unlock(rq
, tsk
, &flags
);
7367 #endif /* CONFIG_CGROUP_SCHED */
7369 #ifdef CONFIG_RT_GROUP_SCHED
7371 * Ensure that the real time constraints are schedulable.
7373 static DEFINE_MUTEX(rt_constraints_mutex
);
7375 /* Must be called with tasklist_lock held */
7376 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7378 struct task_struct
*g
, *p
;
7380 do_each_thread(g
, p
) {
7381 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
7383 } while_each_thread(g
, p
);
7388 struct rt_schedulable_data
{
7389 struct task_group
*tg
;
7394 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7396 struct rt_schedulable_data
*d
= data
;
7397 struct task_group
*child
;
7398 unsigned long total
, sum
= 0;
7399 u64 period
, runtime
;
7401 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7402 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7405 period
= d
->rt_period
;
7406 runtime
= d
->rt_runtime
;
7410 * Cannot have more runtime than the period.
7412 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7416 * Ensure we don't starve existing RT tasks.
7418 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7421 total
= to_ratio(period
, runtime
);
7424 * Nobody can have more than the global setting allows.
7426 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7430 * The sum of our children's runtime should not exceed our own.
7432 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7433 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7434 runtime
= child
->rt_bandwidth
.rt_runtime
;
7436 if (child
== d
->tg
) {
7437 period
= d
->rt_period
;
7438 runtime
= d
->rt_runtime
;
7441 sum
+= to_ratio(period
, runtime
);
7450 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7454 struct rt_schedulable_data data
= {
7456 .rt_period
= period
,
7457 .rt_runtime
= runtime
,
7461 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7467 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7468 u64 rt_period
, u64 rt_runtime
)
7472 mutex_lock(&rt_constraints_mutex
);
7473 read_lock(&tasklist_lock
);
7474 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7478 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7479 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7480 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7482 for_each_possible_cpu(i
) {
7483 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7485 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7486 rt_rq
->rt_runtime
= rt_runtime
;
7487 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7489 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7491 read_unlock(&tasklist_lock
);
7492 mutex_unlock(&rt_constraints_mutex
);
7497 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7499 u64 rt_runtime
, rt_period
;
7501 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7502 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7503 if (rt_runtime_us
< 0)
7504 rt_runtime
= RUNTIME_INF
;
7506 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7509 static long sched_group_rt_runtime(struct task_group
*tg
)
7513 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7516 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7517 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7518 return rt_runtime_us
;
7521 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7523 u64 rt_runtime
, rt_period
;
7525 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7526 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7531 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7534 static long sched_group_rt_period(struct task_group
*tg
)
7538 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7539 do_div(rt_period_us
, NSEC_PER_USEC
);
7540 return rt_period_us
;
7542 #endif /* CONFIG_RT_GROUP_SCHED */
7544 #ifdef CONFIG_RT_GROUP_SCHED
7545 static int sched_rt_global_constraints(void)
7549 mutex_lock(&rt_constraints_mutex
);
7550 read_lock(&tasklist_lock
);
7551 ret
= __rt_schedulable(NULL
, 0, 0);
7552 read_unlock(&tasklist_lock
);
7553 mutex_unlock(&rt_constraints_mutex
);
7558 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7560 /* Don't accept realtime tasks when there is no way for them to run */
7561 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7567 #else /* !CONFIG_RT_GROUP_SCHED */
7568 static int sched_rt_global_constraints(void)
7570 unsigned long flags
;
7573 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7574 for_each_possible_cpu(i
) {
7575 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7577 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7578 rt_rq
->rt_runtime
= global_rt_runtime();
7579 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7581 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7585 #endif /* CONFIG_RT_GROUP_SCHED */
7587 static int sched_dl_global_constraints(void)
7589 u64 runtime
= global_rt_runtime();
7590 u64 period
= global_rt_period();
7591 u64 new_bw
= to_ratio(period
, runtime
);
7593 unsigned long flags
;
7596 * Here we want to check the bandwidth not being set to some
7597 * value smaller than the currently allocated bandwidth in
7598 * any of the root_domains.
7600 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7601 * cycling on root_domains... Discussion on different/better
7602 * solutions is welcome!
7604 for_each_possible_cpu(cpu
) {
7605 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
7607 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7608 if (new_bw
< dl_b
->total_bw
)
7610 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7619 static void sched_dl_do_global(void)
7623 unsigned long flags
;
7625 def_dl_bandwidth
.dl_period
= global_rt_period();
7626 def_dl_bandwidth
.dl_runtime
= global_rt_runtime();
7628 if (global_rt_runtime() != RUNTIME_INF
)
7629 new_bw
= to_ratio(global_rt_period(), global_rt_runtime());
7632 * FIXME: As above...
7634 for_each_possible_cpu(cpu
) {
7635 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
7637 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7639 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7643 static int sched_rt_global_validate(void)
7645 if (sysctl_sched_rt_period
<= 0)
7648 if ((sysctl_sched_rt_runtime
!= RUNTIME_INF
) &&
7649 (sysctl_sched_rt_runtime
> sysctl_sched_rt_period
))
7655 static void sched_rt_do_global(void)
7657 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7658 def_rt_bandwidth
.rt_period
= ns_to_ktime(global_rt_period());
7661 int sched_rt_handler(struct ctl_table
*table
, int write
,
7662 void __user
*buffer
, size_t *lenp
,
7665 int old_period
, old_runtime
;
7666 static DEFINE_MUTEX(mutex
);
7670 old_period
= sysctl_sched_rt_period
;
7671 old_runtime
= sysctl_sched_rt_runtime
;
7673 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7675 if (!ret
&& write
) {
7676 ret
= sched_rt_global_validate();
7680 ret
= sched_rt_global_constraints();
7684 ret
= sched_dl_global_constraints();
7688 sched_rt_do_global();
7689 sched_dl_do_global();
7693 sysctl_sched_rt_period
= old_period
;
7694 sysctl_sched_rt_runtime
= old_runtime
;
7696 mutex_unlock(&mutex
);
7701 int sched_rr_handler(struct ctl_table
*table
, int write
,
7702 void __user
*buffer
, size_t *lenp
,
7706 static DEFINE_MUTEX(mutex
);
7709 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7710 /* make sure that internally we keep jiffies */
7711 /* also, writing zero resets timeslice to default */
7712 if (!ret
&& write
) {
7713 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7714 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7716 mutex_unlock(&mutex
);
7720 #ifdef CONFIG_CGROUP_SCHED
7722 static inline struct task_group
*css_tg(struct cgroup_subsys_state
*css
)
7724 return css
? container_of(css
, struct task_group
, css
) : NULL
;
7727 static struct cgroup_subsys_state
*
7728 cpu_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
7730 struct task_group
*parent
= css_tg(parent_css
);
7731 struct task_group
*tg
;
7734 /* This is early initialization for the top cgroup */
7735 return &root_task_group
.css
;
7738 tg
= sched_create_group(parent
);
7740 return ERR_PTR(-ENOMEM
);
7745 static int cpu_cgroup_css_online(struct cgroup_subsys_state
*css
)
7747 struct task_group
*tg
= css_tg(css
);
7748 struct task_group
*parent
= css_tg(css
->parent
);
7751 sched_online_group(tg
, parent
);
7755 static void cpu_cgroup_css_free(struct cgroup_subsys_state
*css
)
7757 struct task_group
*tg
= css_tg(css
);
7759 sched_destroy_group(tg
);
7762 static void cpu_cgroup_css_offline(struct cgroup_subsys_state
*css
)
7764 struct task_group
*tg
= css_tg(css
);
7766 sched_offline_group(tg
);
7769 static int cpu_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7770 struct cgroup_taskset
*tset
)
7772 struct task_struct
*task
;
7774 cgroup_taskset_for_each(task
, tset
) {
7775 #ifdef CONFIG_RT_GROUP_SCHED
7776 if (!sched_rt_can_attach(css_tg(css
), task
))
7779 /* We don't support RT-tasks being in separate groups */
7780 if (task
->sched_class
!= &fair_sched_class
)
7787 static void cpu_cgroup_attach(struct cgroup_subsys_state
*css
,
7788 struct cgroup_taskset
*tset
)
7790 struct task_struct
*task
;
7792 cgroup_taskset_for_each(task
, tset
)
7793 sched_move_task(task
);
7796 static void cpu_cgroup_exit(struct cgroup_subsys_state
*css
,
7797 struct cgroup_subsys_state
*old_css
,
7798 struct task_struct
*task
)
7801 * cgroup_exit() is called in the copy_process() failure path.
7802 * Ignore this case since the task hasn't ran yet, this avoids
7803 * trying to poke a half freed task state from generic code.
7805 if (!(task
->flags
& PF_EXITING
))
7808 sched_move_task(task
);
7811 #ifdef CONFIG_FAIR_GROUP_SCHED
7812 static int cpu_shares_write_u64(struct cgroup_subsys_state
*css
,
7813 struct cftype
*cftype
, u64 shareval
)
7815 return sched_group_set_shares(css_tg(css
), scale_load(shareval
));
7818 static u64
cpu_shares_read_u64(struct cgroup_subsys_state
*css
,
7821 struct task_group
*tg
= css_tg(css
);
7823 return (u64
) scale_load_down(tg
->shares
);
7826 #ifdef CONFIG_CFS_BANDWIDTH
7827 static DEFINE_MUTEX(cfs_constraints_mutex
);
7829 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7830 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7832 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7834 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7836 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7837 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7839 if (tg
== &root_task_group
)
7843 * Ensure we have at some amount of bandwidth every period. This is
7844 * to prevent reaching a state of large arrears when throttled via
7845 * entity_tick() resulting in prolonged exit starvation.
7847 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7851 * Likewise, bound things on the otherside by preventing insane quota
7852 * periods. This also allows us to normalize in computing quota
7855 if (period
> max_cfs_quota_period
)
7859 * Prevent race between setting of cfs_rq->runtime_enabled and
7860 * unthrottle_offline_cfs_rqs().
7863 mutex_lock(&cfs_constraints_mutex
);
7864 ret
= __cfs_schedulable(tg
, period
, quota
);
7868 runtime_enabled
= quota
!= RUNTIME_INF
;
7869 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7871 * If we need to toggle cfs_bandwidth_used, off->on must occur
7872 * before making related changes, and on->off must occur afterwards
7874 if (runtime_enabled
&& !runtime_was_enabled
)
7875 cfs_bandwidth_usage_inc();
7876 raw_spin_lock_irq(&cfs_b
->lock
);
7877 cfs_b
->period
= ns_to_ktime(period
);
7878 cfs_b
->quota
= quota
;
7880 __refill_cfs_bandwidth_runtime(cfs_b
);
7881 /* restart the period timer (if active) to handle new period expiry */
7882 if (runtime_enabled
&& cfs_b
->timer_active
) {
7883 /* force a reprogram */
7884 __start_cfs_bandwidth(cfs_b
, true);
7886 raw_spin_unlock_irq(&cfs_b
->lock
);
7888 for_each_online_cpu(i
) {
7889 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7890 struct rq
*rq
= cfs_rq
->rq
;
7892 raw_spin_lock_irq(&rq
->lock
);
7893 cfs_rq
->runtime_enabled
= runtime_enabled
;
7894 cfs_rq
->runtime_remaining
= 0;
7896 if (cfs_rq
->throttled
)
7897 unthrottle_cfs_rq(cfs_rq
);
7898 raw_spin_unlock_irq(&rq
->lock
);
7900 if (runtime_was_enabled
&& !runtime_enabled
)
7901 cfs_bandwidth_usage_dec();
7903 mutex_unlock(&cfs_constraints_mutex
);
7909 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7913 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7914 if (cfs_quota_us
< 0)
7915 quota
= RUNTIME_INF
;
7917 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7919 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7922 long tg_get_cfs_quota(struct task_group
*tg
)
7926 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7929 quota_us
= tg
->cfs_bandwidth
.quota
;
7930 do_div(quota_us
, NSEC_PER_USEC
);
7935 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7939 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7940 quota
= tg
->cfs_bandwidth
.quota
;
7942 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7945 long tg_get_cfs_period(struct task_group
*tg
)
7949 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7950 do_div(cfs_period_us
, NSEC_PER_USEC
);
7952 return cfs_period_us
;
7955 static s64
cpu_cfs_quota_read_s64(struct cgroup_subsys_state
*css
,
7958 return tg_get_cfs_quota(css_tg(css
));
7961 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state
*css
,
7962 struct cftype
*cftype
, s64 cfs_quota_us
)
7964 return tg_set_cfs_quota(css_tg(css
), cfs_quota_us
);
7967 static u64
cpu_cfs_period_read_u64(struct cgroup_subsys_state
*css
,
7970 return tg_get_cfs_period(css_tg(css
));
7973 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state
*css
,
7974 struct cftype
*cftype
, u64 cfs_period_us
)
7976 return tg_set_cfs_period(css_tg(css
), cfs_period_us
);
7979 struct cfs_schedulable_data
{
7980 struct task_group
*tg
;
7985 * normalize group quota/period to be quota/max_period
7986 * note: units are usecs
7988 static u64
normalize_cfs_quota(struct task_group
*tg
,
7989 struct cfs_schedulable_data
*d
)
7997 period
= tg_get_cfs_period(tg
);
7998 quota
= tg_get_cfs_quota(tg
);
8001 /* note: these should typically be equivalent */
8002 if (quota
== RUNTIME_INF
|| quota
== -1)
8005 return to_ratio(period
, quota
);
8008 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
8010 struct cfs_schedulable_data
*d
= data
;
8011 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8012 s64 quota
= 0, parent_quota
= -1;
8015 quota
= RUNTIME_INF
;
8017 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
8019 quota
= normalize_cfs_quota(tg
, d
);
8020 parent_quota
= parent_b
->hierarchal_quota
;
8023 * ensure max(child_quota) <= parent_quota, inherit when no
8026 if (quota
== RUNTIME_INF
)
8027 quota
= parent_quota
;
8028 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
8031 cfs_b
->hierarchal_quota
= quota
;
8036 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
8039 struct cfs_schedulable_data data
= {
8045 if (quota
!= RUNTIME_INF
) {
8046 do_div(data
.period
, NSEC_PER_USEC
);
8047 do_div(data
.quota
, NSEC_PER_USEC
);
8051 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
8057 static int cpu_stats_show(struct seq_file
*sf
, void *v
)
8059 struct task_group
*tg
= css_tg(seq_css(sf
));
8060 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8062 seq_printf(sf
, "nr_periods %d\n", cfs_b
->nr_periods
);
8063 seq_printf(sf
, "nr_throttled %d\n", cfs_b
->nr_throttled
);
8064 seq_printf(sf
, "throttled_time %llu\n", cfs_b
->throttled_time
);
8068 #endif /* CONFIG_CFS_BANDWIDTH */
8069 #endif /* CONFIG_FAIR_GROUP_SCHED */
8071 #ifdef CONFIG_RT_GROUP_SCHED
8072 static int cpu_rt_runtime_write(struct cgroup_subsys_state
*css
,
8073 struct cftype
*cft
, s64 val
)
8075 return sched_group_set_rt_runtime(css_tg(css
), val
);
8078 static s64
cpu_rt_runtime_read(struct cgroup_subsys_state
*css
,
8081 return sched_group_rt_runtime(css_tg(css
));
8084 static int cpu_rt_period_write_uint(struct cgroup_subsys_state
*css
,
8085 struct cftype
*cftype
, u64 rt_period_us
)
8087 return sched_group_set_rt_period(css_tg(css
), rt_period_us
);
8090 static u64
cpu_rt_period_read_uint(struct cgroup_subsys_state
*css
,
8093 return sched_group_rt_period(css_tg(css
));
8095 #endif /* CONFIG_RT_GROUP_SCHED */
8097 static struct cftype cpu_files
[] = {
8098 #ifdef CONFIG_FAIR_GROUP_SCHED
8101 .read_u64
= cpu_shares_read_u64
,
8102 .write_u64
= cpu_shares_write_u64
,
8105 #ifdef CONFIG_CFS_BANDWIDTH
8107 .name
= "cfs_quota_us",
8108 .read_s64
= cpu_cfs_quota_read_s64
,
8109 .write_s64
= cpu_cfs_quota_write_s64
,
8112 .name
= "cfs_period_us",
8113 .read_u64
= cpu_cfs_period_read_u64
,
8114 .write_u64
= cpu_cfs_period_write_u64
,
8118 .seq_show
= cpu_stats_show
,
8121 #ifdef CONFIG_RT_GROUP_SCHED
8123 .name
= "rt_runtime_us",
8124 .read_s64
= cpu_rt_runtime_read
,
8125 .write_s64
= cpu_rt_runtime_write
,
8128 .name
= "rt_period_us",
8129 .read_u64
= cpu_rt_period_read_uint
,
8130 .write_u64
= cpu_rt_period_write_uint
,
8136 struct cgroup_subsys cpu_cgrp_subsys
= {
8137 .css_alloc
= cpu_cgroup_css_alloc
,
8138 .css_free
= cpu_cgroup_css_free
,
8139 .css_online
= cpu_cgroup_css_online
,
8140 .css_offline
= cpu_cgroup_css_offline
,
8141 .can_attach
= cpu_cgroup_can_attach
,
8142 .attach
= cpu_cgroup_attach
,
8143 .exit
= cpu_cgroup_exit
,
8144 .legacy_cftypes
= cpu_files
,
8148 #endif /* CONFIG_CGROUP_SCHED */
8150 void dump_cpu_task(int cpu
)
8152 pr_info("Task dump for CPU %d:\n", cpu
);
8153 sched_show_task(cpu_curr(cpu
));