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
;
2369 unsigned long long nr_context_switches(void)
2372 unsigned long long sum
= 0;
2374 for_each_possible_cpu(i
)
2375 sum
+= cpu_rq(i
)->nr_switches
;
2380 unsigned long nr_iowait(void)
2382 unsigned long i
, sum
= 0;
2384 for_each_possible_cpu(i
)
2385 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2390 unsigned long nr_iowait_cpu(int cpu
)
2392 struct rq
*this = cpu_rq(cpu
);
2393 return atomic_read(&this->nr_iowait
);
2399 * sched_exec - execve() is a valuable balancing opportunity, because at
2400 * this point the task has the smallest effective memory and cache footprint.
2402 void sched_exec(void)
2404 struct task_struct
*p
= current
;
2405 unsigned long flags
;
2408 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2409 dest_cpu
= p
->sched_class
->select_task_rq(p
, task_cpu(p
), SD_BALANCE_EXEC
, 0);
2410 if (dest_cpu
== smp_processor_id())
2413 if (likely(cpu_active(dest_cpu
))) {
2414 struct migration_arg arg
= { p
, dest_cpu
};
2416 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2417 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2421 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2426 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2427 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2429 EXPORT_PER_CPU_SYMBOL(kstat
);
2430 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2433 * Return any ns on the sched_clock that have not yet been accounted in
2434 * @p in case that task is currently running.
2436 * Called with task_rq_lock() held on @rq.
2438 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
2443 * Must be ->curr _and_ ->on_rq. If dequeued, we would
2444 * project cycles that may never be accounted to this
2445 * thread, breaking clock_gettime().
2447 if (task_current(rq
, p
) && p
->on_rq
) {
2448 update_rq_clock(rq
);
2449 ns
= rq_clock_task(rq
) - p
->se
.exec_start
;
2457 unsigned long long task_delta_exec(struct task_struct
*p
)
2459 unsigned long flags
;
2463 rq
= task_rq_lock(p
, &flags
);
2464 ns
= do_task_delta_exec(p
, rq
);
2465 task_rq_unlock(rq
, p
, &flags
);
2471 * Return accounted runtime for the task.
2472 * In case the task is currently running, return the runtime plus current's
2473 * pending runtime that have not been accounted yet.
2475 unsigned long long task_sched_runtime(struct task_struct
*p
)
2477 unsigned long flags
;
2481 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2483 * 64-bit doesn't need locks to atomically read a 64bit value.
2484 * So we have a optimization chance when the task's delta_exec is 0.
2485 * Reading ->on_cpu is racy, but this is ok.
2487 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2488 * If we race with it entering cpu, unaccounted time is 0. This is
2489 * indistinguishable from the read occurring a few cycles earlier.
2490 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
2491 * been accounted, so we're correct here as well.
2493 if (!p
->on_cpu
|| !p
->on_rq
)
2494 return p
->se
.sum_exec_runtime
;
2497 rq
= task_rq_lock(p
, &flags
);
2498 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
2499 task_rq_unlock(rq
, p
, &flags
);
2505 * This function gets called by the timer code, with HZ frequency.
2506 * We call it with interrupts disabled.
2508 void scheduler_tick(void)
2510 int cpu
= smp_processor_id();
2511 struct rq
*rq
= cpu_rq(cpu
);
2512 struct task_struct
*curr
= rq
->curr
;
2516 raw_spin_lock(&rq
->lock
);
2517 update_rq_clock(rq
);
2518 curr
->sched_class
->task_tick(rq
, curr
, 0);
2519 update_cpu_load_active(rq
);
2520 raw_spin_unlock(&rq
->lock
);
2522 perf_event_task_tick();
2525 rq
->idle_balance
= idle_cpu(cpu
);
2526 trigger_load_balance(rq
);
2528 rq_last_tick_reset(rq
);
2531 #ifdef CONFIG_NO_HZ_FULL
2533 * scheduler_tick_max_deferment
2535 * Keep at least one tick per second when a single
2536 * active task is running because the scheduler doesn't
2537 * yet completely support full dynticks environment.
2539 * This makes sure that uptime, CFS vruntime, load
2540 * balancing, etc... continue to move forward, even
2541 * with a very low granularity.
2543 * Return: Maximum deferment in nanoseconds.
2545 u64
scheduler_tick_max_deferment(void)
2547 struct rq
*rq
= this_rq();
2548 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2550 next
= rq
->last_sched_tick
+ HZ
;
2552 if (time_before_eq(next
, now
))
2555 return jiffies_to_nsecs(next
- now
);
2559 notrace
unsigned long get_parent_ip(unsigned long addr
)
2561 if (in_lock_functions(addr
)) {
2562 addr
= CALLER_ADDR2
;
2563 if (in_lock_functions(addr
))
2564 addr
= CALLER_ADDR3
;
2569 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2570 defined(CONFIG_PREEMPT_TRACER))
2572 void preempt_count_add(int val
)
2574 #ifdef CONFIG_DEBUG_PREEMPT
2578 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2581 __preempt_count_add(val
);
2582 #ifdef CONFIG_DEBUG_PREEMPT
2584 * Spinlock count overflowing soon?
2586 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2589 if (preempt_count() == val
) {
2590 unsigned long ip
= get_parent_ip(CALLER_ADDR1
);
2591 #ifdef CONFIG_DEBUG_PREEMPT
2592 current
->preempt_disable_ip
= ip
;
2594 trace_preempt_off(CALLER_ADDR0
, ip
);
2597 EXPORT_SYMBOL(preempt_count_add
);
2598 NOKPROBE_SYMBOL(preempt_count_add
);
2600 void preempt_count_sub(int val
)
2602 #ifdef CONFIG_DEBUG_PREEMPT
2606 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2609 * Is the spinlock portion underflowing?
2611 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2612 !(preempt_count() & PREEMPT_MASK
)))
2616 if (preempt_count() == val
)
2617 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2618 __preempt_count_sub(val
);
2620 EXPORT_SYMBOL(preempt_count_sub
);
2621 NOKPROBE_SYMBOL(preempt_count_sub
);
2626 * Print scheduling while atomic bug:
2628 static noinline
void __schedule_bug(struct task_struct
*prev
)
2630 if (oops_in_progress
)
2633 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2634 prev
->comm
, prev
->pid
, preempt_count());
2636 debug_show_held_locks(prev
);
2638 if (irqs_disabled())
2639 print_irqtrace_events(prev
);
2640 #ifdef CONFIG_DEBUG_PREEMPT
2641 if (in_atomic_preempt_off()) {
2642 pr_err("Preemption disabled at:");
2643 print_ip_sym(current
->preempt_disable_ip
);
2648 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2652 * Various schedule()-time debugging checks and statistics:
2654 static inline void schedule_debug(struct task_struct
*prev
)
2657 * Test if we are atomic. Since do_exit() needs to call into
2658 * schedule() atomically, we ignore that path. Otherwise whine
2659 * if we are scheduling when we should not.
2661 if (unlikely(in_atomic_preempt_off() && prev
->state
!= TASK_DEAD
))
2662 __schedule_bug(prev
);
2665 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2667 schedstat_inc(this_rq(), sched_count
);
2671 * Pick up the highest-prio task:
2673 static inline struct task_struct
*
2674 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
2676 const struct sched_class
*class = &fair_sched_class
;
2677 struct task_struct
*p
;
2680 * Optimization: we know that if all tasks are in
2681 * the fair class we can call that function directly:
2683 if (likely(prev
->sched_class
== class &&
2684 rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2685 p
= fair_sched_class
.pick_next_task(rq
, prev
);
2686 if (unlikely(p
== RETRY_TASK
))
2689 /* assumes fair_sched_class->next == idle_sched_class */
2691 p
= idle_sched_class
.pick_next_task(rq
, prev
);
2697 for_each_class(class) {
2698 p
= class->pick_next_task(rq
, prev
);
2700 if (unlikely(p
== RETRY_TASK
))
2706 BUG(); /* the idle class will always have a runnable task */
2710 * __schedule() is the main scheduler function.
2712 * The main means of driving the scheduler and thus entering this function are:
2714 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2716 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2717 * paths. For example, see arch/x86/entry_64.S.
2719 * To drive preemption between tasks, the scheduler sets the flag in timer
2720 * interrupt handler scheduler_tick().
2722 * 3. Wakeups don't really cause entry into schedule(). They add a
2723 * task to the run-queue and that's it.
2725 * Now, if the new task added to the run-queue preempts the current
2726 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2727 * called on the nearest possible occasion:
2729 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2731 * - in syscall or exception context, at the next outmost
2732 * preempt_enable(). (this might be as soon as the wake_up()'s
2735 * - in IRQ context, return from interrupt-handler to
2736 * preemptible context
2738 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2741 * - cond_resched() call
2742 * - explicit schedule() call
2743 * - return from syscall or exception to user-space
2744 * - return from interrupt-handler to user-space
2746 static void __sched
__schedule(void)
2748 struct task_struct
*prev
, *next
;
2749 unsigned long *switch_count
;
2755 cpu
= smp_processor_id();
2757 rcu_note_context_switch(cpu
);
2760 schedule_debug(prev
);
2762 if (sched_feat(HRTICK
))
2766 * Make sure that signal_pending_state()->signal_pending() below
2767 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2768 * done by the caller to avoid the race with signal_wake_up().
2770 smp_mb__before_spinlock();
2771 raw_spin_lock_irq(&rq
->lock
);
2773 switch_count
= &prev
->nivcsw
;
2774 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2775 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2776 prev
->state
= TASK_RUNNING
;
2778 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2782 * If a worker went to sleep, notify and ask workqueue
2783 * whether it wants to wake up a task to maintain
2786 if (prev
->flags
& PF_WQ_WORKER
) {
2787 struct task_struct
*to_wakeup
;
2789 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2791 try_to_wake_up_local(to_wakeup
);
2794 switch_count
= &prev
->nvcsw
;
2797 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
2798 update_rq_clock(rq
);
2800 next
= pick_next_task(rq
, prev
);
2801 clear_tsk_need_resched(prev
);
2802 clear_preempt_need_resched();
2803 rq
->skip_clock_update
= 0;
2805 if (likely(prev
!= next
)) {
2810 context_switch(rq
, prev
, next
); /* unlocks the rq */
2812 * The context switch have flipped the stack from under us
2813 * and restored the local variables which were saved when
2814 * this task called schedule() in the past. prev == current
2815 * is still correct, but it can be moved to another cpu/rq.
2817 cpu
= smp_processor_id();
2820 raw_spin_unlock_irq(&rq
->lock
);
2824 sched_preempt_enable_no_resched();
2829 static inline void sched_submit_work(struct task_struct
*tsk
)
2831 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2834 * If we are going to sleep and we have plugged IO queued,
2835 * make sure to submit it to avoid deadlocks.
2837 if (blk_needs_flush_plug(tsk
))
2838 blk_schedule_flush_plug(tsk
);
2841 asmlinkage __visible
void __sched
schedule(void)
2843 struct task_struct
*tsk
= current
;
2845 sched_submit_work(tsk
);
2848 EXPORT_SYMBOL(schedule
);
2850 #ifdef CONFIG_CONTEXT_TRACKING
2851 asmlinkage __visible
void __sched
schedule_user(void)
2854 * If we come here after a random call to set_need_resched(),
2855 * or we have been woken up remotely but the IPI has not yet arrived,
2856 * we haven't yet exited the RCU idle mode. Do it here manually until
2857 * we find a better solution.
2866 * schedule_preempt_disabled - called with preemption disabled
2868 * Returns with preemption disabled. Note: preempt_count must be 1
2870 void __sched
schedule_preempt_disabled(void)
2872 sched_preempt_enable_no_resched();
2877 #ifdef CONFIG_PREEMPT
2879 * this is the entry point to schedule() from in-kernel preemption
2880 * off of preempt_enable. Kernel preemptions off return from interrupt
2881 * occur there and call schedule directly.
2883 asmlinkage __visible
void __sched notrace
preempt_schedule(void)
2886 * If there is a non-zero preempt_count or interrupts are disabled,
2887 * we do not want to preempt the current task. Just return..
2889 if (likely(!preemptible()))
2893 __preempt_count_add(PREEMPT_ACTIVE
);
2895 __preempt_count_sub(PREEMPT_ACTIVE
);
2898 * Check again in case we missed a preemption opportunity
2899 * between schedule and now.
2902 } while (need_resched());
2904 NOKPROBE_SYMBOL(preempt_schedule
);
2905 EXPORT_SYMBOL(preempt_schedule
);
2906 #endif /* CONFIG_PREEMPT */
2909 * this is the entry point to schedule() from kernel preemption
2910 * off of irq context.
2911 * Note, that this is called and return with irqs disabled. This will
2912 * protect us against recursive calling from irq.
2914 asmlinkage __visible
void __sched
preempt_schedule_irq(void)
2916 enum ctx_state prev_state
;
2918 /* Catch callers which need to be fixed */
2919 BUG_ON(preempt_count() || !irqs_disabled());
2921 prev_state
= exception_enter();
2924 __preempt_count_add(PREEMPT_ACTIVE
);
2927 local_irq_disable();
2928 __preempt_count_sub(PREEMPT_ACTIVE
);
2931 * Check again in case we missed a preemption opportunity
2932 * between schedule and now.
2935 } while (need_resched());
2937 exception_exit(prev_state
);
2940 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2943 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2945 EXPORT_SYMBOL(default_wake_function
);
2947 #ifdef CONFIG_RT_MUTEXES
2950 * rt_mutex_setprio - set the current priority of a task
2952 * @prio: prio value (kernel-internal form)
2954 * This function changes the 'effective' priority of a task. It does
2955 * not touch ->normal_prio like __setscheduler().
2957 * Used by the rt_mutex code to implement priority inheritance
2958 * logic. Call site only calls if the priority of the task changed.
2960 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
2962 int oldprio
, on_rq
, running
, enqueue_flag
= 0;
2964 const struct sched_class
*prev_class
;
2966 BUG_ON(prio
> MAX_PRIO
);
2968 rq
= __task_rq_lock(p
);
2971 * Idle task boosting is a nono in general. There is one
2972 * exception, when PREEMPT_RT and NOHZ is active:
2974 * The idle task calls get_next_timer_interrupt() and holds
2975 * the timer wheel base->lock on the CPU and another CPU wants
2976 * to access the timer (probably to cancel it). We can safely
2977 * ignore the boosting request, as the idle CPU runs this code
2978 * with interrupts disabled and will complete the lock
2979 * protected section without being interrupted. So there is no
2980 * real need to boost.
2982 if (unlikely(p
== rq
->idle
)) {
2983 WARN_ON(p
!= rq
->curr
);
2984 WARN_ON(p
->pi_blocked_on
);
2988 trace_sched_pi_setprio(p
, prio
);
2990 prev_class
= p
->sched_class
;
2992 running
= task_current(rq
, p
);
2994 dequeue_task(rq
, p
, 0);
2996 p
->sched_class
->put_prev_task(rq
, p
);
2999 * Boosting condition are:
3000 * 1. -rt task is running and holds mutex A
3001 * --> -dl task blocks on mutex A
3003 * 2. -dl task is running and holds mutex A
3004 * --> -dl task blocks on mutex A and could preempt the
3007 if (dl_prio(prio
)) {
3008 struct task_struct
*pi_task
= rt_mutex_get_top_task(p
);
3009 if (!dl_prio(p
->normal_prio
) ||
3010 (pi_task
&& dl_entity_preempt(&pi_task
->dl
, &p
->dl
))) {
3011 p
->dl
.dl_boosted
= 1;
3012 p
->dl
.dl_throttled
= 0;
3013 enqueue_flag
= ENQUEUE_REPLENISH
;
3015 p
->dl
.dl_boosted
= 0;
3016 p
->sched_class
= &dl_sched_class
;
3017 } else if (rt_prio(prio
)) {
3018 if (dl_prio(oldprio
))
3019 p
->dl
.dl_boosted
= 0;
3021 enqueue_flag
= ENQUEUE_HEAD
;
3022 p
->sched_class
= &rt_sched_class
;
3024 if (dl_prio(oldprio
))
3025 p
->dl
.dl_boosted
= 0;
3026 p
->sched_class
= &fair_sched_class
;
3032 p
->sched_class
->set_curr_task(rq
);
3034 enqueue_task(rq
, p
, enqueue_flag
);
3036 check_class_changed(rq
, p
, prev_class
, oldprio
);
3038 __task_rq_unlock(rq
);
3042 void set_user_nice(struct task_struct
*p
, long nice
)
3044 int old_prio
, delta
, on_rq
;
3045 unsigned long flags
;
3048 if (task_nice(p
) == nice
|| nice
< MIN_NICE
|| nice
> MAX_NICE
)
3051 * We have to be careful, if called from sys_setpriority(),
3052 * the task might be in the middle of scheduling on another CPU.
3054 rq
= task_rq_lock(p
, &flags
);
3056 * The RT priorities are set via sched_setscheduler(), but we still
3057 * allow the 'normal' nice value to be set - but as expected
3058 * it wont have any effect on scheduling until the task is
3059 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3061 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
3062 p
->static_prio
= NICE_TO_PRIO(nice
);
3067 dequeue_task(rq
, p
, 0);
3069 p
->static_prio
= NICE_TO_PRIO(nice
);
3072 p
->prio
= effective_prio(p
);
3073 delta
= p
->prio
- old_prio
;
3076 enqueue_task(rq
, p
, 0);
3078 * If the task increased its priority or is running and
3079 * lowered its priority, then reschedule its CPU:
3081 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3085 task_rq_unlock(rq
, p
, &flags
);
3087 EXPORT_SYMBOL(set_user_nice
);
3090 * can_nice - check if a task can reduce its nice value
3094 int can_nice(const struct task_struct
*p
, const int nice
)
3096 /* convert nice value [19,-20] to rlimit style value [1,40] */
3097 int nice_rlim
= nice_to_rlimit(nice
);
3099 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3100 capable(CAP_SYS_NICE
));
3103 #ifdef __ARCH_WANT_SYS_NICE
3106 * sys_nice - change the priority of the current process.
3107 * @increment: priority increment
3109 * sys_setpriority is a more generic, but much slower function that
3110 * does similar things.
3112 SYSCALL_DEFINE1(nice
, int, increment
)
3117 * Setpriority might change our priority at the same moment.
3118 * We don't have to worry. Conceptually one call occurs first
3119 * and we have a single winner.
3121 increment
= clamp(increment
, -NICE_WIDTH
, NICE_WIDTH
);
3122 nice
= task_nice(current
) + increment
;
3124 nice
= clamp_val(nice
, MIN_NICE
, MAX_NICE
);
3125 if (increment
< 0 && !can_nice(current
, nice
))
3128 retval
= security_task_setnice(current
, nice
);
3132 set_user_nice(current
, nice
);
3139 * task_prio - return the priority value of a given task.
3140 * @p: the task in question.
3142 * Return: The priority value as seen by users in /proc.
3143 * RT tasks are offset by -200. Normal tasks are centered
3144 * around 0, value goes from -16 to +15.
3146 int task_prio(const struct task_struct
*p
)
3148 return p
->prio
- MAX_RT_PRIO
;
3152 * idle_cpu - is a given cpu idle currently?
3153 * @cpu: the processor in question.
3155 * Return: 1 if the CPU is currently idle. 0 otherwise.
3157 int idle_cpu(int cpu
)
3159 struct rq
*rq
= cpu_rq(cpu
);
3161 if (rq
->curr
!= rq
->idle
)
3168 if (!llist_empty(&rq
->wake_list
))
3176 * idle_task - return the idle task for a given cpu.
3177 * @cpu: the processor in question.
3179 * Return: The idle task for the cpu @cpu.
3181 struct task_struct
*idle_task(int cpu
)
3183 return cpu_rq(cpu
)->idle
;
3187 * find_process_by_pid - find a process with a matching PID value.
3188 * @pid: the pid in question.
3190 * The task of @pid, if found. %NULL otherwise.
3192 static struct task_struct
*find_process_by_pid(pid_t pid
)
3194 return pid
? find_task_by_vpid(pid
) : current
;
3198 * This function initializes the sched_dl_entity of a newly becoming
3199 * SCHED_DEADLINE task.
3201 * Only the static values are considered here, the actual runtime and the
3202 * absolute deadline will be properly calculated when the task is enqueued
3203 * for the first time with its new policy.
3206 __setparam_dl(struct task_struct
*p
, const struct sched_attr
*attr
)
3208 struct sched_dl_entity
*dl_se
= &p
->dl
;
3210 init_dl_task_timer(dl_se
);
3211 dl_se
->dl_runtime
= attr
->sched_runtime
;
3212 dl_se
->dl_deadline
= attr
->sched_deadline
;
3213 dl_se
->dl_period
= attr
->sched_period
?: dl_se
->dl_deadline
;
3214 dl_se
->flags
= attr
->sched_flags
;
3215 dl_se
->dl_bw
= to_ratio(dl_se
->dl_period
, dl_se
->dl_runtime
);
3216 dl_se
->dl_throttled
= 0;
3218 dl_se
->dl_yielded
= 0;
3222 * sched_setparam() passes in -1 for its policy, to let the functions
3223 * it calls know not to change it.
3225 #define SETPARAM_POLICY -1
3227 static void __setscheduler_params(struct task_struct
*p
,
3228 const struct sched_attr
*attr
)
3230 int policy
= attr
->sched_policy
;
3232 if (policy
== SETPARAM_POLICY
)
3237 if (dl_policy(policy
))
3238 __setparam_dl(p
, attr
);
3239 else if (fair_policy(policy
))
3240 p
->static_prio
= NICE_TO_PRIO(attr
->sched_nice
);
3243 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3244 * !rt_policy. Always setting this ensures that things like
3245 * getparam()/getattr() don't report silly values for !rt tasks.
3247 p
->rt_priority
= attr
->sched_priority
;
3248 p
->normal_prio
= normal_prio(p
);
3252 /* Actually do priority change: must hold pi & rq lock. */
3253 static void __setscheduler(struct rq
*rq
, struct task_struct
*p
,
3254 const struct sched_attr
*attr
)
3256 __setscheduler_params(p
, attr
);
3259 * If we get here, there was no pi waiters boosting the
3260 * task. It is safe to use the normal prio.
3262 p
->prio
= normal_prio(p
);
3264 if (dl_prio(p
->prio
))
3265 p
->sched_class
= &dl_sched_class
;
3266 else if (rt_prio(p
->prio
))
3267 p
->sched_class
= &rt_sched_class
;
3269 p
->sched_class
= &fair_sched_class
;
3273 __getparam_dl(struct task_struct
*p
, struct sched_attr
*attr
)
3275 struct sched_dl_entity
*dl_se
= &p
->dl
;
3277 attr
->sched_priority
= p
->rt_priority
;
3278 attr
->sched_runtime
= dl_se
->dl_runtime
;
3279 attr
->sched_deadline
= dl_se
->dl_deadline
;
3280 attr
->sched_period
= dl_se
->dl_period
;
3281 attr
->sched_flags
= dl_se
->flags
;
3285 * This function validates the new parameters of a -deadline task.
3286 * We ask for the deadline not being zero, and greater or equal
3287 * than the runtime, as well as the period of being zero or
3288 * greater than deadline. Furthermore, we have to be sure that
3289 * user parameters are above the internal resolution of 1us (we
3290 * check sched_runtime only since it is always the smaller one) and
3291 * below 2^63 ns (we have to check both sched_deadline and
3292 * sched_period, as the latter can be zero).
3295 __checkparam_dl(const struct sched_attr
*attr
)
3298 if (attr
->sched_deadline
== 0)
3302 * Since we truncate DL_SCALE bits, make sure we're at least
3305 if (attr
->sched_runtime
< (1ULL << DL_SCALE
))
3309 * Since we use the MSB for wrap-around and sign issues, make
3310 * sure it's not set (mind that period can be equal to zero).
3312 if (attr
->sched_deadline
& (1ULL << 63) ||
3313 attr
->sched_period
& (1ULL << 63))
3316 /* runtime <= deadline <= period (if period != 0) */
3317 if ((attr
->sched_period
!= 0 &&
3318 attr
->sched_period
< attr
->sched_deadline
) ||
3319 attr
->sched_deadline
< attr
->sched_runtime
)
3326 * check the target process has a UID that matches the current process's
3328 static bool check_same_owner(struct task_struct
*p
)
3330 const struct cred
*cred
= current_cred(), *pcred
;
3334 pcred
= __task_cred(p
);
3335 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3336 uid_eq(cred
->euid
, pcred
->uid
));
3341 static int __sched_setscheduler(struct task_struct
*p
,
3342 const struct sched_attr
*attr
,
3345 int newprio
= dl_policy(attr
->sched_policy
) ? MAX_DL_PRIO
- 1 :
3346 MAX_RT_PRIO
- 1 - attr
->sched_priority
;
3347 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
3348 int policy
= attr
->sched_policy
;
3349 unsigned long flags
;
3350 const struct sched_class
*prev_class
;
3354 /* may grab non-irq protected spin_locks */
3355 BUG_ON(in_interrupt());
3357 /* double check policy once rq lock held */
3359 reset_on_fork
= p
->sched_reset_on_fork
;
3360 policy
= oldpolicy
= p
->policy
;
3362 reset_on_fork
= !!(attr
->sched_flags
& SCHED_FLAG_RESET_ON_FORK
);
3364 if (policy
!= SCHED_DEADLINE
&&
3365 policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3366 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3367 policy
!= SCHED_IDLE
)
3371 if (attr
->sched_flags
& ~(SCHED_FLAG_RESET_ON_FORK
))
3375 * Valid priorities for SCHED_FIFO and SCHED_RR are
3376 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3377 * SCHED_BATCH and SCHED_IDLE is 0.
3379 if ((p
->mm
&& attr
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3380 (!p
->mm
&& attr
->sched_priority
> MAX_RT_PRIO
-1))
3382 if ((dl_policy(policy
) && !__checkparam_dl(attr
)) ||
3383 (rt_policy(policy
) != (attr
->sched_priority
!= 0)))
3387 * Allow unprivileged RT tasks to decrease priority:
3389 if (user
&& !capable(CAP_SYS_NICE
)) {
3390 if (fair_policy(policy
)) {
3391 if (attr
->sched_nice
< task_nice(p
) &&
3392 !can_nice(p
, attr
->sched_nice
))
3396 if (rt_policy(policy
)) {
3397 unsigned long rlim_rtprio
=
3398 task_rlimit(p
, RLIMIT_RTPRIO
);
3400 /* can't set/change the rt policy */
3401 if (policy
!= p
->policy
&& !rlim_rtprio
)
3404 /* can't increase priority */
3405 if (attr
->sched_priority
> p
->rt_priority
&&
3406 attr
->sched_priority
> rlim_rtprio
)
3411 * Can't set/change SCHED_DEADLINE policy at all for now
3412 * (safest behavior); in the future we would like to allow
3413 * unprivileged DL tasks to increase their relative deadline
3414 * or reduce their runtime (both ways reducing utilization)
3416 if (dl_policy(policy
))
3420 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3421 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3423 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3424 if (!can_nice(p
, task_nice(p
)))
3428 /* can't change other user's priorities */
3429 if (!check_same_owner(p
))
3432 /* Normal users shall not reset the sched_reset_on_fork flag */
3433 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3438 retval
= security_task_setscheduler(p
);
3444 * make sure no PI-waiters arrive (or leave) while we are
3445 * changing the priority of the task:
3447 * To be able to change p->policy safely, the appropriate
3448 * runqueue lock must be held.
3450 rq
= task_rq_lock(p
, &flags
);
3453 * Changing the policy of the stop threads its a very bad idea
3455 if (p
== rq
->stop
) {
3456 task_rq_unlock(rq
, p
, &flags
);
3461 * If not changing anything there's no need to proceed further,
3462 * but store a possible modification of reset_on_fork.
3464 if (unlikely(policy
== p
->policy
)) {
3465 if (fair_policy(policy
) && attr
->sched_nice
!= task_nice(p
))
3467 if (rt_policy(policy
) && attr
->sched_priority
!= p
->rt_priority
)
3469 if (dl_policy(policy
))
3472 p
->sched_reset_on_fork
= reset_on_fork
;
3473 task_rq_unlock(rq
, p
, &flags
);
3479 #ifdef CONFIG_RT_GROUP_SCHED
3481 * Do not allow realtime tasks into groups that have no runtime
3484 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3485 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3486 !task_group_is_autogroup(task_group(p
))) {
3487 task_rq_unlock(rq
, p
, &flags
);
3492 if (dl_bandwidth_enabled() && dl_policy(policy
)) {
3493 cpumask_t
*span
= rq
->rd
->span
;
3496 * Don't allow tasks with an affinity mask smaller than
3497 * the entire root_domain to become SCHED_DEADLINE. We
3498 * will also fail if there's no bandwidth available.
3500 if (!cpumask_subset(span
, &p
->cpus_allowed
) ||
3501 rq
->rd
->dl_bw
.bw
== 0) {
3502 task_rq_unlock(rq
, p
, &flags
);
3509 /* recheck policy now with rq lock held */
3510 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3511 policy
= oldpolicy
= -1;
3512 task_rq_unlock(rq
, p
, &flags
);
3517 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3518 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3521 if ((dl_policy(policy
) || dl_task(p
)) && dl_overflow(p
, policy
, attr
)) {
3522 task_rq_unlock(rq
, p
, &flags
);
3526 p
->sched_reset_on_fork
= reset_on_fork
;
3530 * Special case for priority boosted tasks.
3532 * If the new priority is lower or equal (user space view)
3533 * than the current (boosted) priority, we just store the new
3534 * normal parameters and do not touch the scheduler class and
3535 * the runqueue. This will be done when the task deboost
3538 if (rt_mutex_check_prio(p
, newprio
)) {
3539 __setscheduler_params(p
, attr
);
3540 task_rq_unlock(rq
, p
, &flags
);
3545 running
= task_current(rq
, p
);
3547 dequeue_task(rq
, p
, 0);
3549 p
->sched_class
->put_prev_task(rq
, p
);
3551 prev_class
= p
->sched_class
;
3552 __setscheduler(rq
, p
, attr
);
3555 p
->sched_class
->set_curr_task(rq
);
3558 * We enqueue to tail when the priority of a task is
3559 * increased (user space view).
3561 enqueue_task(rq
, p
, oldprio
<= p
->prio
? ENQUEUE_HEAD
: 0);
3564 check_class_changed(rq
, p
, prev_class
, oldprio
);
3565 task_rq_unlock(rq
, p
, &flags
);
3567 rt_mutex_adjust_pi(p
);
3572 static int _sched_setscheduler(struct task_struct
*p
, int policy
,
3573 const struct sched_param
*param
, bool check
)
3575 struct sched_attr attr
= {
3576 .sched_policy
= policy
,
3577 .sched_priority
= param
->sched_priority
,
3578 .sched_nice
= PRIO_TO_NICE(p
->static_prio
),
3581 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
3582 if ((policy
!= SETPARAM_POLICY
) && (policy
& SCHED_RESET_ON_FORK
)) {
3583 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3584 policy
&= ~SCHED_RESET_ON_FORK
;
3585 attr
.sched_policy
= policy
;
3588 return __sched_setscheduler(p
, &attr
, check
);
3591 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3592 * @p: the task in question.
3593 * @policy: new policy.
3594 * @param: structure containing the new RT priority.
3596 * Return: 0 on success. An error code otherwise.
3598 * NOTE that the task may be already dead.
3600 int sched_setscheduler(struct task_struct
*p
, int policy
,
3601 const struct sched_param
*param
)
3603 return _sched_setscheduler(p
, policy
, param
, true);
3605 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3607 int sched_setattr(struct task_struct
*p
, const struct sched_attr
*attr
)
3609 return __sched_setscheduler(p
, attr
, true);
3611 EXPORT_SYMBOL_GPL(sched_setattr
);
3614 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3615 * @p: the task in question.
3616 * @policy: new policy.
3617 * @param: structure containing the new RT priority.
3619 * Just like sched_setscheduler, only don't bother checking if the
3620 * current context has permission. For example, this is needed in
3621 * stop_machine(): we create temporary high priority worker threads,
3622 * but our caller might not have that capability.
3624 * Return: 0 on success. An error code otherwise.
3626 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3627 const struct sched_param
*param
)
3629 return _sched_setscheduler(p
, policy
, param
, false);
3633 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3635 struct sched_param lparam
;
3636 struct task_struct
*p
;
3639 if (!param
|| pid
< 0)
3641 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3646 p
= find_process_by_pid(pid
);
3648 retval
= sched_setscheduler(p
, policy
, &lparam
);
3655 * Mimics kernel/events/core.c perf_copy_attr().
3657 static int sched_copy_attr(struct sched_attr __user
*uattr
,
3658 struct sched_attr
*attr
)
3663 if (!access_ok(VERIFY_WRITE
, uattr
, SCHED_ATTR_SIZE_VER0
))
3667 * zero the full structure, so that a short copy will be nice.
3669 memset(attr
, 0, sizeof(*attr
));
3671 ret
= get_user(size
, &uattr
->size
);
3675 if (size
> PAGE_SIZE
) /* silly large */
3678 if (!size
) /* abi compat */
3679 size
= SCHED_ATTR_SIZE_VER0
;
3681 if (size
< SCHED_ATTR_SIZE_VER0
)
3685 * If we're handed a bigger struct than we know of,
3686 * ensure all the unknown bits are 0 - i.e. new
3687 * user-space does not rely on any kernel feature
3688 * extensions we dont know about yet.
3690 if (size
> sizeof(*attr
)) {
3691 unsigned char __user
*addr
;
3692 unsigned char __user
*end
;
3695 addr
= (void __user
*)uattr
+ sizeof(*attr
);
3696 end
= (void __user
*)uattr
+ size
;
3698 for (; addr
< end
; addr
++) {
3699 ret
= get_user(val
, addr
);
3705 size
= sizeof(*attr
);
3708 ret
= copy_from_user(attr
, uattr
, size
);
3713 * XXX: do we want to be lenient like existing syscalls; or do we want
3714 * to be strict and return an error on out-of-bounds values?
3716 attr
->sched_nice
= clamp(attr
->sched_nice
, MIN_NICE
, MAX_NICE
);
3721 put_user(sizeof(*attr
), &uattr
->size
);
3726 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3727 * @pid: the pid in question.
3728 * @policy: new policy.
3729 * @param: structure containing the new RT priority.
3731 * Return: 0 on success. An error code otherwise.
3733 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3734 struct sched_param __user
*, param
)
3736 /* negative values for policy are not valid */
3740 return do_sched_setscheduler(pid
, policy
, param
);
3744 * sys_sched_setparam - set/change the RT priority of a thread
3745 * @pid: the pid in question.
3746 * @param: structure containing the new RT priority.
3748 * Return: 0 on success. An error code otherwise.
3750 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3752 return do_sched_setscheduler(pid
, SETPARAM_POLICY
, param
);
3756 * sys_sched_setattr - same as above, but with extended sched_attr
3757 * @pid: the pid in question.
3758 * @uattr: structure containing the extended parameters.
3759 * @flags: for future extension.
3761 SYSCALL_DEFINE3(sched_setattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3762 unsigned int, flags
)
3764 struct sched_attr attr
;
3765 struct task_struct
*p
;
3768 if (!uattr
|| pid
< 0 || flags
)
3771 retval
= sched_copy_attr(uattr
, &attr
);
3775 if ((int)attr
.sched_policy
< 0)
3780 p
= find_process_by_pid(pid
);
3782 retval
= sched_setattr(p
, &attr
);
3789 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3790 * @pid: the pid in question.
3792 * Return: On success, the policy of the thread. Otherwise, a negative error
3795 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3797 struct task_struct
*p
;
3805 p
= find_process_by_pid(pid
);
3807 retval
= security_task_getscheduler(p
);
3810 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3817 * sys_sched_getparam - get the RT priority of a thread
3818 * @pid: the pid in question.
3819 * @param: structure containing the RT priority.
3821 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3824 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3826 struct sched_param lp
= { .sched_priority
= 0 };
3827 struct task_struct
*p
;
3830 if (!param
|| pid
< 0)
3834 p
= find_process_by_pid(pid
);
3839 retval
= security_task_getscheduler(p
);
3843 if (task_has_rt_policy(p
))
3844 lp
.sched_priority
= p
->rt_priority
;
3848 * This one might sleep, we cannot do it with a spinlock held ...
3850 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3859 static int sched_read_attr(struct sched_attr __user
*uattr
,
3860 struct sched_attr
*attr
,
3865 if (!access_ok(VERIFY_WRITE
, uattr
, usize
))
3869 * If we're handed a smaller struct than we know of,
3870 * ensure all the unknown bits are 0 - i.e. old
3871 * user-space does not get uncomplete information.
3873 if (usize
< sizeof(*attr
)) {
3874 unsigned char *addr
;
3877 addr
= (void *)attr
+ usize
;
3878 end
= (void *)attr
+ sizeof(*attr
);
3880 for (; addr
< end
; addr
++) {
3888 ret
= copy_to_user(uattr
, attr
, attr
->size
);
3896 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
3897 * @pid: the pid in question.
3898 * @uattr: structure containing the extended parameters.
3899 * @size: sizeof(attr) for fwd/bwd comp.
3900 * @flags: for future extension.
3902 SYSCALL_DEFINE4(sched_getattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3903 unsigned int, size
, unsigned int, flags
)
3905 struct sched_attr attr
= {
3906 .size
= sizeof(struct sched_attr
),
3908 struct task_struct
*p
;
3911 if (!uattr
|| pid
< 0 || size
> PAGE_SIZE
||
3912 size
< SCHED_ATTR_SIZE_VER0
|| flags
)
3916 p
= find_process_by_pid(pid
);
3921 retval
= security_task_getscheduler(p
);
3925 attr
.sched_policy
= p
->policy
;
3926 if (p
->sched_reset_on_fork
)
3927 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3928 if (task_has_dl_policy(p
))
3929 __getparam_dl(p
, &attr
);
3930 else if (task_has_rt_policy(p
))
3931 attr
.sched_priority
= p
->rt_priority
;
3933 attr
.sched_nice
= task_nice(p
);
3937 retval
= sched_read_attr(uattr
, &attr
, size
);
3945 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
3947 cpumask_var_t cpus_allowed
, new_mask
;
3948 struct task_struct
*p
;
3953 p
= find_process_by_pid(pid
);
3959 /* Prevent p going away */
3963 if (p
->flags
& PF_NO_SETAFFINITY
) {
3967 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
3971 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
3973 goto out_free_cpus_allowed
;
3976 if (!check_same_owner(p
)) {
3978 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
3985 retval
= security_task_setscheduler(p
);
3990 cpuset_cpus_allowed(p
, cpus_allowed
);
3991 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
3994 * Since bandwidth control happens on root_domain basis,
3995 * if admission test is enabled, we only admit -deadline
3996 * tasks allowed to run on all the CPUs in the task's
4000 if (task_has_dl_policy(p
)) {
4001 const struct cpumask
*span
= task_rq(p
)->rd
->span
;
4003 if (dl_bandwidth_enabled() && !cpumask_subset(span
, new_mask
)) {
4010 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4013 cpuset_cpus_allowed(p
, cpus_allowed
);
4014 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4016 * We must have raced with a concurrent cpuset
4017 * update. Just reset the cpus_allowed to the
4018 * cpuset's cpus_allowed
4020 cpumask_copy(new_mask
, cpus_allowed
);
4025 free_cpumask_var(new_mask
);
4026 out_free_cpus_allowed
:
4027 free_cpumask_var(cpus_allowed
);
4033 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4034 struct cpumask
*new_mask
)
4036 if (len
< cpumask_size())
4037 cpumask_clear(new_mask
);
4038 else if (len
> cpumask_size())
4039 len
= cpumask_size();
4041 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4045 * sys_sched_setaffinity - set the cpu affinity of a process
4046 * @pid: pid of the process
4047 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4048 * @user_mask_ptr: user-space pointer to the new cpu mask
4050 * Return: 0 on success. An error code otherwise.
4052 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4053 unsigned long __user
*, user_mask_ptr
)
4055 cpumask_var_t new_mask
;
4058 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4061 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4063 retval
= sched_setaffinity(pid
, new_mask
);
4064 free_cpumask_var(new_mask
);
4068 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4070 struct task_struct
*p
;
4071 unsigned long flags
;
4077 p
= find_process_by_pid(pid
);
4081 retval
= security_task_getscheduler(p
);
4085 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4086 cpumask_and(mask
, &p
->cpus_allowed
, cpu_active_mask
);
4087 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4096 * sys_sched_getaffinity - get the cpu affinity of a process
4097 * @pid: pid of the process
4098 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4099 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4101 * Return: 0 on success. An error code otherwise.
4103 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4104 unsigned long __user
*, user_mask_ptr
)
4109 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4111 if (len
& (sizeof(unsigned long)-1))
4114 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4117 ret
= sched_getaffinity(pid
, mask
);
4119 size_t retlen
= min_t(size_t, len
, cpumask_size());
4121 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4126 free_cpumask_var(mask
);
4132 * sys_sched_yield - yield the current processor to other threads.
4134 * This function yields the current CPU to other tasks. If there are no
4135 * other threads running on this CPU then this function will return.
4139 SYSCALL_DEFINE0(sched_yield
)
4141 struct rq
*rq
= this_rq_lock();
4143 schedstat_inc(rq
, yld_count
);
4144 current
->sched_class
->yield_task(rq
);
4147 * Since we are going to call schedule() anyway, there's
4148 * no need to preempt or enable interrupts:
4150 __release(rq
->lock
);
4151 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4152 do_raw_spin_unlock(&rq
->lock
);
4153 sched_preempt_enable_no_resched();
4160 static void __cond_resched(void)
4162 __preempt_count_add(PREEMPT_ACTIVE
);
4164 __preempt_count_sub(PREEMPT_ACTIVE
);
4167 int __sched
_cond_resched(void)
4169 if (should_resched()) {
4175 EXPORT_SYMBOL(_cond_resched
);
4178 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4179 * call schedule, and on return reacquire the lock.
4181 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4182 * operations here to prevent schedule() from being called twice (once via
4183 * spin_unlock(), once by hand).
4185 int __cond_resched_lock(spinlock_t
*lock
)
4187 int resched
= should_resched();
4190 lockdep_assert_held(lock
);
4192 if (spin_needbreak(lock
) || resched
) {
4203 EXPORT_SYMBOL(__cond_resched_lock
);
4205 int __sched
__cond_resched_softirq(void)
4207 BUG_ON(!in_softirq());
4209 if (should_resched()) {
4217 EXPORT_SYMBOL(__cond_resched_softirq
);
4220 * yield - yield the current processor to other threads.
4222 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4224 * The scheduler is at all times free to pick the calling task as the most
4225 * eligible task to run, if removing the yield() call from your code breaks
4226 * it, its already broken.
4228 * Typical broken usage is:
4233 * where one assumes that yield() will let 'the other' process run that will
4234 * make event true. If the current task is a SCHED_FIFO task that will never
4235 * happen. Never use yield() as a progress guarantee!!
4237 * If you want to use yield() to wait for something, use wait_event().
4238 * If you want to use yield() to be 'nice' for others, use cond_resched().
4239 * If you still want to use yield(), do not!
4241 void __sched
yield(void)
4243 set_current_state(TASK_RUNNING
);
4246 EXPORT_SYMBOL(yield
);
4249 * yield_to - yield the current processor to another thread in
4250 * your thread group, or accelerate that thread toward the
4251 * processor it's on.
4253 * @preempt: whether task preemption is allowed or not
4255 * It's the caller's job to ensure that the target task struct
4256 * can't go away on us before we can do any checks.
4259 * true (>0) if we indeed boosted the target task.
4260 * false (0) if we failed to boost the target.
4261 * -ESRCH if there's no task to yield to.
4263 int __sched
yield_to(struct task_struct
*p
, bool preempt
)
4265 struct task_struct
*curr
= current
;
4266 struct rq
*rq
, *p_rq
;
4267 unsigned long flags
;
4270 local_irq_save(flags
);
4276 * If we're the only runnable task on the rq and target rq also
4277 * has only one task, there's absolutely no point in yielding.
4279 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
4284 double_rq_lock(rq
, p_rq
);
4285 if (task_rq(p
) != p_rq
) {
4286 double_rq_unlock(rq
, p_rq
);
4290 if (!curr
->sched_class
->yield_to_task
)
4293 if (curr
->sched_class
!= p
->sched_class
)
4296 if (task_running(p_rq
, p
) || p
->state
)
4299 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4301 schedstat_inc(rq
, yld_count
);
4303 * Make p's CPU reschedule; pick_next_entity takes care of
4306 if (preempt
&& rq
!= p_rq
)
4311 double_rq_unlock(rq
, p_rq
);
4313 local_irq_restore(flags
);
4320 EXPORT_SYMBOL_GPL(yield_to
);
4323 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4324 * that process accounting knows that this is a task in IO wait state.
4326 void __sched
io_schedule(void)
4328 struct rq
*rq
= raw_rq();
4330 delayacct_blkio_start();
4331 atomic_inc(&rq
->nr_iowait
);
4332 blk_flush_plug(current
);
4333 current
->in_iowait
= 1;
4335 current
->in_iowait
= 0;
4336 atomic_dec(&rq
->nr_iowait
);
4337 delayacct_blkio_end();
4339 EXPORT_SYMBOL(io_schedule
);
4341 long __sched
io_schedule_timeout(long timeout
)
4343 struct rq
*rq
= raw_rq();
4346 delayacct_blkio_start();
4347 atomic_inc(&rq
->nr_iowait
);
4348 blk_flush_plug(current
);
4349 current
->in_iowait
= 1;
4350 ret
= schedule_timeout(timeout
);
4351 current
->in_iowait
= 0;
4352 atomic_dec(&rq
->nr_iowait
);
4353 delayacct_blkio_end();
4358 * sys_sched_get_priority_max - return maximum RT priority.
4359 * @policy: scheduling class.
4361 * Return: On success, this syscall returns the maximum
4362 * rt_priority that can be used by a given scheduling class.
4363 * On failure, a negative error code is returned.
4365 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4372 ret
= MAX_USER_RT_PRIO
-1;
4374 case SCHED_DEADLINE
:
4385 * sys_sched_get_priority_min - return minimum RT priority.
4386 * @policy: scheduling class.
4388 * Return: On success, this syscall returns the minimum
4389 * rt_priority that can be used by a given scheduling class.
4390 * On failure, a negative error code is returned.
4392 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4401 case SCHED_DEADLINE
:
4411 * sys_sched_rr_get_interval - return the default timeslice of a process.
4412 * @pid: pid of the process.
4413 * @interval: userspace pointer to the timeslice value.
4415 * this syscall writes the default timeslice value of a given process
4416 * into the user-space timespec buffer. A value of '0' means infinity.
4418 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4421 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4422 struct timespec __user
*, interval
)
4424 struct task_struct
*p
;
4425 unsigned int time_slice
;
4426 unsigned long flags
;
4436 p
= find_process_by_pid(pid
);
4440 retval
= security_task_getscheduler(p
);
4444 rq
= task_rq_lock(p
, &flags
);
4446 if (p
->sched_class
->get_rr_interval
)
4447 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4448 task_rq_unlock(rq
, p
, &flags
);
4451 jiffies_to_timespec(time_slice
, &t
);
4452 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4460 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4462 void sched_show_task(struct task_struct
*p
)
4464 unsigned long free
= 0;
4468 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4469 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4470 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4471 #if BITS_PER_LONG == 32
4472 if (state
== TASK_RUNNING
)
4473 printk(KERN_CONT
" running ");
4475 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4477 if (state
== TASK_RUNNING
)
4478 printk(KERN_CONT
" running task ");
4480 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4482 #ifdef CONFIG_DEBUG_STACK_USAGE
4483 free
= stack_not_used(p
);
4486 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4488 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4489 task_pid_nr(p
), ppid
,
4490 (unsigned long)task_thread_info(p
)->flags
);
4492 print_worker_info(KERN_INFO
, p
);
4493 show_stack(p
, NULL
);
4496 void show_state_filter(unsigned long state_filter
)
4498 struct task_struct
*g
, *p
;
4500 #if BITS_PER_LONG == 32
4502 " task PC stack pid father\n");
4505 " task PC stack pid father\n");
4508 do_each_thread(g
, p
) {
4510 * reset the NMI-timeout, listing all files on a slow
4511 * console might take a lot of time:
4513 touch_nmi_watchdog();
4514 if (!state_filter
|| (p
->state
& state_filter
))
4516 } while_each_thread(g
, p
);
4518 touch_all_softlockup_watchdogs();
4520 #ifdef CONFIG_SCHED_DEBUG
4521 sysrq_sched_debug_show();
4525 * Only show locks if all tasks are dumped:
4528 debug_show_all_locks();
4531 void init_idle_bootup_task(struct task_struct
*idle
)
4533 idle
->sched_class
= &idle_sched_class
;
4537 * init_idle - set up an idle thread for a given CPU
4538 * @idle: task in question
4539 * @cpu: cpu the idle task belongs to
4541 * NOTE: this function does not set the idle thread's NEED_RESCHED
4542 * flag, to make booting more robust.
4544 void init_idle(struct task_struct
*idle
, int cpu
)
4546 struct rq
*rq
= cpu_rq(cpu
);
4547 unsigned long flags
;
4549 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4551 __sched_fork(0, idle
);
4552 idle
->state
= TASK_RUNNING
;
4553 idle
->se
.exec_start
= sched_clock();
4555 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4557 * We're having a chicken and egg problem, even though we are
4558 * holding rq->lock, the cpu isn't yet set to this cpu so the
4559 * lockdep check in task_group() will fail.
4561 * Similar case to sched_fork(). / Alternatively we could
4562 * use task_rq_lock() here and obtain the other rq->lock.
4567 __set_task_cpu(idle
, cpu
);
4570 rq
->curr
= rq
->idle
= idle
;
4572 #if defined(CONFIG_SMP)
4575 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4577 /* Set the preempt count _outside_ the spinlocks! */
4578 init_idle_preempt_count(idle
, cpu
);
4581 * The idle tasks have their own, simple scheduling class:
4583 idle
->sched_class
= &idle_sched_class
;
4584 ftrace_graph_init_idle_task(idle
, cpu
);
4585 vtime_init_idle(idle
, cpu
);
4586 #if defined(CONFIG_SMP)
4587 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4592 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4594 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4595 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4597 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4598 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4602 * This is how migration works:
4604 * 1) we invoke migration_cpu_stop() on the target CPU using
4606 * 2) stopper starts to run (implicitly forcing the migrated thread
4608 * 3) it checks whether the migrated task is still in the wrong runqueue.
4609 * 4) if it's in the wrong runqueue then the migration thread removes
4610 * it and puts it into the right queue.
4611 * 5) stopper completes and stop_one_cpu() returns and the migration
4616 * Change a given task's CPU affinity. Migrate the thread to a
4617 * proper CPU and schedule it away if the CPU it's executing on
4618 * is removed from the allowed bitmask.
4620 * NOTE: the caller must have a valid reference to the task, the
4621 * task must not exit() & deallocate itself prematurely. The
4622 * call is not atomic; no spinlocks may be held.
4624 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4626 unsigned long flags
;
4628 unsigned int dest_cpu
;
4631 rq
= task_rq_lock(p
, &flags
);
4633 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4636 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4641 do_set_cpus_allowed(p
, new_mask
);
4643 /* Can the task run on the task's current CPU? If so, we're done */
4644 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4647 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4649 struct migration_arg arg
= { p
, dest_cpu
};
4650 /* Need help from migration thread: drop lock and wait. */
4651 task_rq_unlock(rq
, p
, &flags
);
4652 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4653 tlb_migrate_finish(p
->mm
);
4657 task_rq_unlock(rq
, p
, &flags
);
4661 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4664 * Move (not current) task off this cpu, onto dest cpu. We're doing
4665 * this because either it can't run here any more (set_cpus_allowed()
4666 * away from this CPU, or CPU going down), or because we're
4667 * attempting to rebalance this task on exec (sched_exec).
4669 * So we race with normal scheduler movements, but that's OK, as long
4670 * as the task is no longer on this CPU.
4672 * Returns non-zero if task was successfully migrated.
4674 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4676 struct rq
*rq_dest
, *rq_src
;
4679 if (unlikely(!cpu_active(dest_cpu
)))
4682 rq_src
= cpu_rq(src_cpu
);
4683 rq_dest
= cpu_rq(dest_cpu
);
4685 raw_spin_lock(&p
->pi_lock
);
4686 double_rq_lock(rq_src
, rq_dest
);
4687 /* Already moved. */
4688 if (task_cpu(p
) != src_cpu
)
4690 /* Affinity changed (again). */
4691 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4695 * If we're not on a rq, the next wake-up will ensure we're
4699 dequeue_task(rq_src
, p
, 0);
4700 set_task_cpu(p
, dest_cpu
);
4701 enqueue_task(rq_dest
, p
, 0);
4702 check_preempt_curr(rq_dest
, p
, 0);
4707 double_rq_unlock(rq_src
, rq_dest
);
4708 raw_spin_unlock(&p
->pi_lock
);
4712 #ifdef CONFIG_NUMA_BALANCING
4713 /* Migrate current task p to target_cpu */
4714 int migrate_task_to(struct task_struct
*p
, int target_cpu
)
4716 struct migration_arg arg
= { p
, target_cpu
};
4717 int curr_cpu
= task_cpu(p
);
4719 if (curr_cpu
== target_cpu
)
4722 if (!cpumask_test_cpu(target_cpu
, tsk_cpus_allowed(p
)))
4725 /* TODO: This is not properly updating schedstats */
4727 trace_sched_move_numa(p
, curr_cpu
, target_cpu
);
4728 return stop_one_cpu(curr_cpu
, migration_cpu_stop
, &arg
);
4732 * Requeue a task on a given node and accurately track the number of NUMA
4733 * tasks on the runqueues
4735 void sched_setnuma(struct task_struct
*p
, int nid
)
4738 unsigned long flags
;
4739 bool on_rq
, running
;
4741 rq
= task_rq_lock(p
, &flags
);
4743 running
= task_current(rq
, p
);
4746 dequeue_task(rq
, p
, 0);
4748 p
->sched_class
->put_prev_task(rq
, p
);
4750 p
->numa_preferred_nid
= nid
;
4753 p
->sched_class
->set_curr_task(rq
);
4755 enqueue_task(rq
, p
, 0);
4756 task_rq_unlock(rq
, p
, &flags
);
4761 * migration_cpu_stop - this will be executed by a highprio stopper thread
4762 * and performs thread migration by bumping thread off CPU then
4763 * 'pushing' onto another runqueue.
4765 static int migration_cpu_stop(void *data
)
4767 struct migration_arg
*arg
= data
;
4770 * The original target cpu might have gone down and we might
4771 * be on another cpu but it doesn't matter.
4773 local_irq_disable();
4774 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4779 #ifdef CONFIG_HOTPLUG_CPU
4782 * Ensures that the idle task is using init_mm right before its cpu goes
4785 void idle_task_exit(void)
4787 struct mm_struct
*mm
= current
->active_mm
;
4789 BUG_ON(cpu_online(smp_processor_id()));
4791 if (mm
!= &init_mm
) {
4792 switch_mm(mm
, &init_mm
, current
);
4793 finish_arch_post_lock_switch();
4799 * Since this CPU is going 'away' for a while, fold any nr_active delta
4800 * we might have. Assumes we're called after migrate_tasks() so that the
4801 * nr_active count is stable.
4803 * Also see the comment "Global load-average calculations".
4805 static void calc_load_migrate(struct rq
*rq
)
4807 long delta
= calc_load_fold_active(rq
);
4809 atomic_long_add(delta
, &calc_load_tasks
);
4812 static void put_prev_task_fake(struct rq
*rq
, struct task_struct
*prev
)
4816 static const struct sched_class fake_sched_class
= {
4817 .put_prev_task
= put_prev_task_fake
,
4820 static struct task_struct fake_task
= {
4822 * Avoid pull_{rt,dl}_task()
4824 .prio
= MAX_PRIO
+ 1,
4825 .sched_class
= &fake_sched_class
,
4829 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4830 * try_to_wake_up()->select_task_rq().
4832 * Called with rq->lock held even though we'er in stop_machine() and
4833 * there's no concurrency possible, we hold the required locks anyway
4834 * because of lock validation efforts.
4836 static void migrate_tasks(unsigned int dead_cpu
)
4838 struct rq
*rq
= cpu_rq(dead_cpu
);
4839 struct task_struct
*next
, *stop
= rq
->stop
;
4843 * Fudge the rq selection such that the below task selection loop
4844 * doesn't get stuck on the currently eligible stop task.
4846 * We're currently inside stop_machine() and the rq is either stuck
4847 * in the stop_machine_cpu_stop() loop, or we're executing this code,
4848 * either way we should never end up calling schedule() until we're
4854 * put_prev_task() and pick_next_task() sched
4855 * class method both need to have an up-to-date
4856 * value of rq->clock[_task]
4858 update_rq_clock(rq
);
4862 * There's this thread running, bail when that's the only
4865 if (rq
->nr_running
== 1)
4868 next
= pick_next_task(rq
, &fake_task
);
4870 next
->sched_class
->put_prev_task(rq
, next
);
4872 /* Find suitable destination for @next, with force if needed. */
4873 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
4874 raw_spin_unlock(&rq
->lock
);
4876 __migrate_task(next
, dead_cpu
, dest_cpu
);
4878 raw_spin_lock(&rq
->lock
);
4884 #endif /* CONFIG_HOTPLUG_CPU */
4886 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
4888 static struct ctl_table sd_ctl_dir
[] = {
4890 .procname
= "sched_domain",
4896 static struct ctl_table sd_ctl_root
[] = {
4898 .procname
= "kernel",
4900 .child
= sd_ctl_dir
,
4905 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
4907 struct ctl_table
*entry
=
4908 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
4913 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
4915 struct ctl_table
*entry
;
4918 * In the intermediate directories, both the child directory and
4919 * procname are dynamically allocated and could fail but the mode
4920 * will always be set. In the lowest directory the names are
4921 * static strings and all have proc handlers.
4923 for (entry
= *tablep
; entry
->mode
; entry
++) {
4925 sd_free_ctl_entry(&entry
->child
);
4926 if (entry
->proc_handler
== NULL
)
4927 kfree(entry
->procname
);
4934 static int min_load_idx
= 0;
4935 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
4938 set_table_entry(struct ctl_table
*entry
,
4939 const char *procname
, void *data
, int maxlen
,
4940 umode_t mode
, proc_handler
*proc_handler
,
4943 entry
->procname
= procname
;
4945 entry
->maxlen
= maxlen
;
4947 entry
->proc_handler
= proc_handler
;
4950 entry
->extra1
= &min_load_idx
;
4951 entry
->extra2
= &max_load_idx
;
4955 static struct ctl_table
*
4956 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
4958 struct ctl_table
*table
= sd_alloc_ctl_entry(14);
4963 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
4964 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4965 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
4966 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4967 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
4968 sizeof(int), 0644, proc_dointvec_minmax
, true);
4969 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
4970 sizeof(int), 0644, proc_dointvec_minmax
, true);
4971 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
4972 sizeof(int), 0644, proc_dointvec_minmax
, true);
4973 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
4974 sizeof(int), 0644, proc_dointvec_minmax
, true);
4975 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
4976 sizeof(int), 0644, proc_dointvec_minmax
, true);
4977 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
4978 sizeof(int), 0644, proc_dointvec_minmax
, false);
4979 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
4980 sizeof(int), 0644, proc_dointvec_minmax
, false);
4981 set_table_entry(&table
[9], "cache_nice_tries",
4982 &sd
->cache_nice_tries
,
4983 sizeof(int), 0644, proc_dointvec_minmax
, false);
4984 set_table_entry(&table
[10], "flags", &sd
->flags
,
4985 sizeof(int), 0644, proc_dointvec_minmax
, false);
4986 set_table_entry(&table
[11], "max_newidle_lb_cost",
4987 &sd
->max_newidle_lb_cost
,
4988 sizeof(long), 0644, proc_doulongvec_minmax
, false);
4989 set_table_entry(&table
[12], "name", sd
->name
,
4990 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
4991 /* &table[13] is terminator */
4996 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
4998 struct ctl_table
*entry
, *table
;
4999 struct sched_domain
*sd
;
5000 int domain_num
= 0, i
;
5003 for_each_domain(cpu
, sd
)
5005 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5010 for_each_domain(cpu
, sd
) {
5011 snprintf(buf
, 32, "domain%d", i
);
5012 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5014 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5021 static struct ctl_table_header
*sd_sysctl_header
;
5022 static void register_sched_domain_sysctl(void)
5024 int i
, cpu_num
= num_possible_cpus();
5025 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5028 WARN_ON(sd_ctl_dir
[0].child
);
5029 sd_ctl_dir
[0].child
= entry
;
5034 for_each_possible_cpu(i
) {
5035 snprintf(buf
, 32, "cpu%d", i
);
5036 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5038 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5042 WARN_ON(sd_sysctl_header
);
5043 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5046 /* may be called multiple times per register */
5047 static void unregister_sched_domain_sysctl(void)
5049 if (sd_sysctl_header
)
5050 unregister_sysctl_table(sd_sysctl_header
);
5051 sd_sysctl_header
= NULL
;
5052 if (sd_ctl_dir
[0].child
)
5053 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5056 static void register_sched_domain_sysctl(void)
5059 static void unregister_sched_domain_sysctl(void)
5064 static void set_rq_online(struct rq
*rq
)
5067 const struct sched_class
*class;
5069 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5072 for_each_class(class) {
5073 if (class->rq_online
)
5074 class->rq_online(rq
);
5079 static void set_rq_offline(struct rq
*rq
)
5082 const struct sched_class
*class;
5084 for_each_class(class) {
5085 if (class->rq_offline
)
5086 class->rq_offline(rq
);
5089 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5095 * migration_call - callback that gets triggered when a CPU is added.
5096 * Here we can start up the necessary migration thread for the new CPU.
5099 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5101 int cpu
= (long)hcpu
;
5102 unsigned long flags
;
5103 struct rq
*rq
= cpu_rq(cpu
);
5105 switch (action
& ~CPU_TASKS_FROZEN
) {
5107 case CPU_UP_PREPARE
:
5108 rq
->calc_load_update
= calc_load_update
;
5112 /* Update our root-domain */
5113 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5115 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5119 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5122 #ifdef CONFIG_HOTPLUG_CPU
5124 sched_ttwu_pending();
5125 /* Update our root-domain */
5126 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5128 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5132 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5133 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5137 calc_load_migrate(rq
);
5142 update_max_interval();
5148 * Register at high priority so that task migration (migrate_all_tasks)
5149 * happens before everything else. This has to be lower priority than
5150 * the notifier in the perf_event subsystem, though.
5152 static struct notifier_block migration_notifier
= {
5153 .notifier_call
= migration_call
,
5154 .priority
= CPU_PRI_MIGRATION
,
5157 static void __cpuinit
set_cpu_rq_start_time(void)
5159 int cpu
= smp_processor_id();
5160 struct rq
*rq
= cpu_rq(cpu
);
5161 rq
->age_stamp
= sched_clock_cpu(cpu
);
5164 static int sched_cpu_active(struct notifier_block
*nfb
,
5165 unsigned long action
, void *hcpu
)
5167 switch (action
& ~CPU_TASKS_FROZEN
) {
5169 set_cpu_rq_start_time();
5171 case CPU_DOWN_FAILED
:
5172 set_cpu_active((long)hcpu
, true);
5179 static int sched_cpu_inactive(struct notifier_block
*nfb
,
5180 unsigned long action
, void *hcpu
)
5182 unsigned long flags
;
5183 long cpu
= (long)hcpu
;
5185 switch (action
& ~CPU_TASKS_FROZEN
) {
5186 case CPU_DOWN_PREPARE
:
5187 set_cpu_active(cpu
, false);
5189 /* explicitly allow suspend */
5190 if (!(action
& CPU_TASKS_FROZEN
)) {
5191 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
5195 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
5196 cpus
= dl_bw_cpus(cpu
);
5197 overflow
= __dl_overflow(dl_b
, cpus
, 0, 0);
5198 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
5201 return notifier_from_errno(-EBUSY
);
5209 static int __init
migration_init(void)
5211 void *cpu
= (void *)(long)smp_processor_id();
5214 /* Initialize migration for the boot CPU */
5215 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5216 BUG_ON(err
== NOTIFY_BAD
);
5217 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5218 register_cpu_notifier(&migration_notifier
);
5220 /* Register cpu active notifiers */
5221 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5222 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5226 early_initcall(migration_init
);
5231 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5233 #ifdef CONFIG_SCHED_DEBUG
5235 static __read_mostly
int sched_debug_enabled
;
5237 static int __init
sched_debug_setup(char *str
)
5239 sched_debug_enabled
= 1;
5243 early_param("sched_debug", sched_debug_setup
);
5245 static inline bool sched_debug(void)
5247 return sched_debug_enabled
;
5250 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5251 struct cpumask
*groupmask
)
5253 struct sched_group
*group
= sd
->groups
;
5256 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5257 cpumask_clear(groupmask
);
5259 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5261 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5262 printk("does not load-balance\n");
5264 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5269 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5271 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5272 printk(KERN_ERR
"ERROR: domain->span does not contain "
5275 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5276 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5280 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5284 printk(KERN_ERR
"ERROR: group is NULL\n");
5289 * Even though we initialize ->capacity to something semi-sane,
5290 * we leave capacity_orig unset. This allows us to detect if
5291 * domain iteration is still funny without causing /0 traps.
5293 if (!group
->sgc
->capacity_orig
) {
5294 printk(KERN_CONT
"\n");
5295 printk(KERN_ERR
"ERROR: domain->cpu_capacity not set\n");
5299 if (!cpumask_weight(sched_group_cpus(group
))) {
5300 printk(KERN_CONT
"\n");
5301 printk(KERN_ERR
"ERROR: empty group\n");
5305 if (!(sd
->flags
& SD_OVERLAP
) &&
5306 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5307 printk(KERN_CONT
"\n");
5308 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5312 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5314 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
5316 printk(KERN_CONT
" %s", str
);
5317 if (group
->sgc
->capacity
!= SCHED_CAPACITY_SCALE
) {
5318 printk(KERN_CONT
" (cpu_capacity = %d)",
5319 group
->sgc
->capacity
);
5322 group
= group
->next
;
5323 } while (group
!= sd
->groups
);
5324 printk(KERN_CONT
"\n");
5326 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5327 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5330 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5331 printk(KERN_ERR
"ERROR: parent span is not a superset "
5332 "of domain->span\n");
5336 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5340 if (!sched_debug_enabled
)
5344 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5348 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5351 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5359 #else /* !CONFIG_SCHED_DEBUG */
5360 # define sched_domain_debug(sd, cpu) do { } while (0)
5361 static inline bool sched_debug(void)
5365 #endif /* CONFIG_SCHED_DEBUG */
5367 static int sd_degenerate(struct sched_domain
*sd
)
5369 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5372 /* Following flags need at least 2 groups */
5373 if (sd
->flags
& (SD_LOAD_BALANCE
|
5374 SD_BALANCE_NEWIDLE
|
5377 SD_SHARE_CPUCAPACITY
|
5378 SD_SHARE_PKG_RESOURCES
|
5379 SD_SHARE_POWERDOMAIN
)) {
5380 if (sd
->groups
!= sd
->groups
->next
)
5384 /* Following flags don't use groups */
5385 if (sd
->flags
& (SD_WAKE_AFFINE
))
5392 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5394 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5396 if (sd_degenerate(parent
))
5399 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5402 /* Flags needing groups don't count if only 1 group in parent */
5403 if (parent
->groups
== parent
->groups
->next
) {
5404 pflags
&= ~(SD_LOAD_BALANCE
|
5405 SD_BALANCE_NEWIDLE
|
5408 SD_SHARE_CPUCAPACITY
|
5409 SD_SHARE_PKG_RESOURCES
|
5411 SD_SHARE_POWERDOMAIN
);
5412 if (nr_node_ids
== 1)
5413 pflags
&= ~SD_SERIALIZE
;
5415 if (~cflags
& pflags
)
5421 static void free_rootdomain(struct rcu_head
*rcu
)
5423 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5425 cpupri_cleanup(&rd
->cpupri
);
5426 cpudl_cleanup(&rd
->cpudl
);
5427 free_cpumask_var(rd
->dlo_mask
);
5428 free_cpumask_var(rd
->rto_mask
);
5429 free_cpumask_var(rd
->online
);
5430 free_cpumask_var(rd
->span
);
5434 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5436 struct root_domain
*old_rd
= NULL
;
5437 unsigned long flags
;
5439 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5444 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5447 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5450 * If we dont want to free the old_rd yet then
5451 * set old_rd to NULL to skip the freeing later
5454 if (!atomic_dec_and_test(&old_rd
->refcount
))
5458 atomic_inc(&rd
->refcount
);
5461 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5462 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5465 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5468 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5471 static int init_rootdomain(struct root_domain
*rd
)
5473 memset(rd
, 0, sizeof(*rd
));
5475 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5477 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5479 if (!alloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
5481 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5484 init_dl_bw(&rd
->dl_bw
);
5485 if (cpudl_init(&rd
->cpudl
) != 0)
5488 if (cpupri_init(&rd
->cpupri
) != 0)
5493 free_cpumask_var(rd
->rto_mask
);
5495 free_cpumask_var(rd
->dlo_mask
);
5497 free_cpumask_var(rd
->online
);
5499 free_cpumask_var(rd
->span
);
5505 * By default the system creates a single root-domain with all cpus as
5506 * members (mimicking the global state we have today).
5508 struct root_domain def_root_domain
;
5510 static void init_defrootdomain(void)
5512 init_rootdomain(&def_root_domain
);
5514 atomic_set(&def_root_domain
.refcount
, 1);
5517 static struct root_domain
*alloc_rootdomain(void)
5519 struct root_domain
*rd
;
5521 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5525 if (init_rootdomain(rd
) != 0) {
5533 static void free_sched_groups(struct sched_group
*sg
, int free_sgc
)
5535 struct sched_group
*tmp
, *first
;
5544 if (free_sgc
&& atomic_dec_and_test(&sg
->sgc
->ref
))
5549 } while (sg
!= first
);
5552 static void free_sched_domain(struct rcu_head
*rcu
)
5554 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5557 * If its an overlapping domain it has private groups, iterate and
5560 if (sd
->flags
& SD_OVERLAP
) {
5561 free_sched_groups(sd
->groups
, 1);
5562 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5563 kfree(sd
->groups
->sgc
);
5569 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5571 call_rcu(&sd
->rcu
, free_sched_domain
);
5574 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5576 for (; sd
; sd
= sd
->parent
)
5577 destroy_sched_domain(sd
, cpu
);
5581 * Keep a special pointer to the highest sched_domain that has
5582 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5583 * allows us to avoid some pointer chasing select_idle_sibling().
5585 * Also keep a unique ID per domain (we use the first cpu number in
5586 * the cpumask of the domain), this allows us to quickly tell if
5587 * two cpus are in the same cache domain, see cpus_share_cache().
5589 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5590 DEFINE_PER_CPU(int, sd_llc_size
);
5591 DEFINE_PER_CPU(int, sd_llc_id
);
5592 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
5593 DEFINE_PER_CPU(struct sched_domain
*, sd_busy
);
5594 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
5596 static void update_top_cache_domain(int cpu
)
5598 struct sched_domain
*sd
;
5599 struct sched_domain
*busy_sd
= NULL
;
5603 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5605 id
= cpumask_first(sched_domain_span(sd
));
5606 size
= cpumask_weight(sched_domain_span(sd
));
5607 busy_sd
= sd
->parent
; /* sd_busy */
5609 rcu_assign_pointer(per_cpu(sd_busy
, cpu
), busy_sd
);
5611 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5612 per_cpu(sd_llc_size
, cpu
) = size
;
5613 per_cpu(sd_llc_id
, cpu
) = id
;
5615 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
5616 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
5618 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
5619 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
5623 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5624 * hold the hotplug lock.
5627 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5629 struct rq
*rq
= cpu_rq(cpu
);
5630 struct sched_domain
*tmp
;
5632 /* Remove the sched domains which do not contribute to scheduling. */
5633 for (tmp
= sd
; tmp
; ) {
5634 struct sched_domain
*parent
= tmp
->parent
;
5638 if (sd_parent_degenerate(tmp
, parent
)) {
5639 tmp
->parent
= parent
->parent
;
5641 parent
->parent
->child
= tmp
;
5643 * Transfer SD_PREFER_SIBLING down in case of a
5644 * degenerate parent; the spans match for this
5645 * so the property transfers.
5647 if (parent
->flags
& SD_PREFER_SIBLING
)
5648 tmp
->flags
|= SD_PREFER_SIBLING
;
5649 destroy_sched_domain(parent
, cpu
);
5654 if (sd
&& sd_degenerate(sd
)) {
5657 destroy_sched_domain(tmp
, cpu
);
5662 sched_domain_debug(sd
, cpu
);
5664 rq_attach_root(rq
, rd
);
5666 rcu_assign_pointer(rq
->sd
, sd
);
5667 destroy_sched_domains(tmp
, cpu
);
5669 update_top_cache_domain(cpu
);
5672 /* cpus with isolated domains */
5673 static cpumask_var_t cpu_isolated_map
;
5675 /* Setup the mask of cpus configured for isolated domains */
5676 static int __init
isolated_cpu_setup(char *str
)
5678 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5679 cpulist_parse(str
, cpu_isolated_map
);
5683 __setup("isolcpus=", isolated_cpu_setup
);
5686 struct sched_domain
** __percpu sd
;
5687 struct root_domain
*rd
;
5698 * Build an iteration mask that can exclude certain CPUs from the upwards
5701 * Asymmetric node setups can result in situations where the domain tree is of
5702 * unequal depth, make sure to skip domains that already cover the entire
5705 * In that case build_sched_domains() will have terminated the iteration early
5706 * and our sibling sd spans will be empty. Domains should always include the
5707 * cpu they're built on, so check that.
5710 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5712 const struct cpumask
*span
= sched_domain_span(sd
);
5713 struct sd_data
*sdd
= sd
->private;
5714 struct sched_domain
*sibling
;
5717 for_each_cpu(i
, span
) {
5718 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5719 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5722 cpumask_set_cpu(i
, sched_group_mask(sg
));
5727 * Return the canonical balance cpu for this group, this is the first cpu
5728 * of this group that's also in the iteration mask.
5730 int group_balance_cpu(struct sched_group
*sg
)
5732 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5736 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5738 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5739 const struct cpumask
*span
= sched_domain_span(sd
);
5740 struct cpumask
*covered
= sched_domains_tmpmask
;
5741 struct sd_data
*sdd
= sd
->private;
5742 struct sched_domain
*child
;
5745 cpumask_clear(covered
);
5747 for_each_cpu(i
, span
) {
5748 struct cpumask
*sg_span
;
5750 if (cpumask_test_cpu(i
, covered
))
5753 child
= *per_cpu_ptr(sdd
->sd
, i
);
5755 /* See the comment near build_group_mask(). */
5756 if (!cpumask_test_cpu(i
, sched_domain_span(child
)))
5759 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5760 GFP_KERNEL
, cpu_to_node(cpu
));
5765 sg_span
= sched_group_cpus(sg
);
5767 child
= child
->child
;
5768 cpumask_copy(sg_span
, sched_domain_span(child
));
5770 cpumask_set_cpu(i
, sg_span
);
5772 cpumask_or(covered
, covered
, sg_span
);
5774 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, i
);
5775 if (atomic_inc_return(&sg
->sgc
->ref
) == 1)
5776 build_group_mask(sd
, sg
);
5779 * Initialize sgc->capacity such that even if we mess up the
5780 * domains and no possible iteration will get us here, we won't
5783 sg
->sgc
->capacity
= SCHED_CAPACITY_SCALE
* cpumask_weight(sg_span
);
5784 sg
->sgc
->capacity_orig
= sg
->sgc
->capacity
;
5787 * Make sure the first group of this domain contains the
5788 * canonical balance cpu. Otherwise the sched_domain iteration
5789 * breaks. See update_sg_lb_stats().
5791 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5792 group_balance_cpu(sg
) == cpu
)
5802 sd
->groups
= groups
;
5807 free_sched_groups(first
, 0);
5812 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5814 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5815 struct sched_domain
*child
= sd
->child
;
5818 cpu
= cpumask_first(sched_domain_span(child
));
5821 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5822 (*sg
)->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
5823 atomic_set(&(*sg
)->sgc
->ref
, 1); /* for claim_allocations */
5830 * build_sched_groups will build a circular linked list of the groups
5831 * covered by the given span, and will set each group's ->cpumask correctly,
5832 * and ->cpu_capacity to 0.
5834 * Assumes the sched_domain tree is fully constructed
5837 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5839 struct sched_group
*first
= NULL
, *last
= NULL
;
5840 struct sd_data
*sdd
= sd
->private;
5841 const struct cpumask
*span
= sched_domain_span(sd
);
5842 struct cpumask
*covered
;
5845 get_group(cpu
, sdd
, &sd
->groups
);
5846 atomic_inc(&sd
->groups
->ref
);
5848 if (cpu
!= cpumask_first(span
))
5851 lockdep_assert_held(&sched_domains_mutex
);
5852 covered
= sched_domains_tmpmask
;
5854 cpumask_clear(covered
);
5856 for_each_cpu(i
, span
) {
5857 struct sched_group
*sg
;
5860 if (cpumask_test_cpu(i
, covered
))
5863 group
= get_group(i
, sdd
, &sg
);
5864 cpumask_setall(sched_group_mask(sg
));
5866 for_each_cpu(j
, span
) {
5867 if (get_group(j
, sdd
, NULL
) != group
)
5870 cpumask_set_cpu(j
, covered
);
5871 cpumask_set_cpu(j
, sched_group_cpus(sg
));
5886 * Initialize sched groups cpu_capacity.
5888 * cpu_capacity indicates the capacity of sched group, which is used while
5889 * distributing the load between different sched groups in a sched domain.
5890 * Typically cpu_capacity for all the groups in a sched domain will be same
5891 * unless there are asymmetries in the topology. If there are asymmetries,
5892 * group having more cpu_capacity will pickup more load compared to the
5893 * group having less cpu_capacity.
5895 static void init_sched_groups_capacity(int cpu
, struct sched_domain
*sd
)
5897 struct sched_group
*sg
= sd
->groups
;
5902 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
5904 } while (sg
!= sd
->groups
);
5906 if (cpu
!= group_balance_cpu(sg
))
5909 update_group_capacity(sd
, cpu
);
5910 atomic_set(&sg
->sgc
->nr_busy_cpus
, sg
->group_weight
);
5914 * Initializers for schedule domains
5915 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
5918 static int default_relax_domain_level
= -1;
5919 int sched_domain_level_max
;
5921 static int __init
setup_relax_domain_level(char *str
)
5923 if (kstrtoint(str
, 0, &default_relax_domain_level
))
5924 pr_warn("Unable to set relax_domain_level\n");
5928 __setup("relax_domain_level=", setup_relax_domain_level
);
5930 static void set_domain_attribute(struct sched_domain
*sd
,
5931 struct sched_domain_attr
*attr
)
5935 if (!attr
|| attr
->relax_domain_level
< 0) {
5936 if (default_relax_domain_level
< 0)
5939 request
= default_relax_domain_level
;
5941 request
= attr
->relax_domain_level
;
5942 if (request
< sd
->level
) {
5943 /* turn off idle balance on this domain */
5944 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5946 /* turn on idle balance on this domain */
5947 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
5951 static void __sdt_free(const struct cpumask
*cpu_map
);
5952 static int __sdt_alloc(const struct cpumask
*cpu_map
);
5954 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
5955 const struct cpumask
*cpu_map
)
5959 if (!atomic_read(&d
->rd
->refcount
))
5960 free_rootdomain(&d
->rd
->rcu
); /* fall through */
5962 free_percpu(d
->sd
); /* fall through */
5964 __sdt_free(cpu_map
); /* fall through */
5970 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
5971 const struct cpumask
*cpu_map
)
5973 memset(d
, 0, sizeof(*d
));
5975 if (__sdt_alloc(cpu_map
))
5976 return sa_sd_storage
;
5977 d
->sd
= alloc_percpu(struct sched_domain
*);
5979 return sa_sd_storage
;
5980 d
->rd
= alloc_rootdomain();
5983 return sa_rootdomain
;
5987 * NULL the sd_data elements we've used to build the sched_domain and
5988 * sched_group structure so that the subsequent __free_domain_allocs()
5989 * will not free the data we're using.
5991 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
5993 struct sd_data
*sdd
= sd
->private;
5995 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
5996 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
5998 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
5999 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
6001 if (atomic_read(&(*per_cpu_ptr(sdd
->sgc
, cpu
))->ref
))
6002 *per_cpu_ptr(sdd
->sgc
, cpu
) = NULL
;
6006 static int sched_domains_numa_levels
;
6007 static int *sched_domains_numa_distance
;
6008 static struct cpumask
***sched_domains_numa_masks
;
6009 static int sched_domains_curr_level
;
6013 * SD_flags allowed in topology descriptions.
6015 * SD_SHARE_CPUCAPACITY - describes SMT topologies
6016 * SD_SHARE_PKG_RESOURCES - describes shared caches
6017 * SD_NUMA - describes NUMA topologies
6018 * SD_SHARE_POWERDOMAIN - describes shared power domain
6021 * SD_ASYM_PACKING - describes SMT quirks
6023 #define TOPOLOGY_SD_FLAGS \
6024 (SD_SHARE_CPUCAPACITY | \
6025 SD_SHARE_PKG_RESOURCES | \
6028 SD_SHARE_POWERDOMAIN)
6030 static struct sched_domain
*
6031 sd_init(struct sched_domain_topology_level
*tl
, int cpu
)
6033 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
6034 int sd_weight
, sd_flags
= 0;
6038 * Ugly hack to pass state to sd_numa_mask()...
6040 sched_domains_curr_level
= tl
->numa_level
;
6043 sd_weight
= cpumask_weight(tl
->mask(cpu
));
6046 sd_flags
= (*tl
->sd_flags
)();
6047 if (WARN_ONCE(sd_flags
& ~TOPOLOGY_SD_FLAGS
,
6048 "wrong sd_flags in topology description\n"))
6049 sd_flags
&= ~TOPOLOGY_SD_FLAGS
;
6051 *sd
= (struct sched_domain
){
6052 .min_interval
= sd_weight
,
6053 .max_interval
= 2*sd_weight
,
6055 .imbalance_pct
= 125,
6057 .cache_nice_tries
= 0,
6064 .flags
= 1*SD_LOAD_BALANCE
6065 | 1*SD_BALANCE_NEWIDLE
6070 | 0*SD_SHARE_CPUCAPACITY
6071 | 0*SD_SHARE_PKG_RESOURCES
6073 | 0*SD_PREFER_SIBLING
6078 .last_balance
= jiffies
,
6079 .balance_interval
= sd_weight
,
6081 .max_newidle_lb_cost
= 0,
6082 .next_decay_max_lb_cost
= jiffies
,
6083 #ifdef CONFIG_SCHED_DEBUG
6089 * Convert topological properties into behaviour.
6092 if (sd
->flags
& SD_SHARE_CPUCAPACITY
) {
6093 sd
->imbalance_pct
= 110;
6094 sd
->smt_gain
= 1178; /* ~15% */
6096 } else if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
6097 sd
->imbalance_pct
= 117;
6098 sd
->cache_nice_tries
= 1;
6102 } else if (sd
->flags
& SD_NUMA
) {
6103 sd
->cache_nice_tries
= 2;
6107 sd
->flags
|= SD_SERIALIZE
;
6108 if (sched_domains_numa_distance
[tl
->numa_level
] > RECLAIM_DISTANCE
) {
6109 sd
->flags
&= ~(SD_BALANCE_EXEC
|
6116 sd
->flags
|= SD_PREFER_SIBLING
;
6117 sd
->cache_nice_tries
= 1;
6122 sd
->private = &tl
->data
;
6128 * Topology list, bottom-up.
6130 static struct sched_domain_topology_level default_topology
[] = {
6131 #ifdef CONFIG_SCHED_SMT
6132 { cpu_smt_mask
, cpu_smt_flags
, SD_INIT_NAME(SMT
) },
6134 #ifdef CONFIG_SCHED_MC
6135 { cpu_coregroup_mask
, cpu_core_flags
, SD_INIT_NAME(MC
) },
6137 { cpu_cpu_mask
, SD_INIT_NAME(DIE
) },
6141 struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6143 #define for_each_sd_topology(tl) \
6144 for (tl = sched_domain_topology; tl->mask; tl++)
6146 void set_sched_topology(struct sched_domain_topology_level
*tl
)
6148 sched_domain_topology
= tl
;
6153 static const struct cpumask
*sd_numa_mask(int cpu
)
6155 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6158 static void sched_numa_warn(const char *str
)
6160 static int done
= false;
6168 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6170 for (i
= 0; i
< nr_node_ids
; i
++) {
6171 printk(KERN_WARNING
" ");
6172 for (j
= 0; j
< nr_node_ids
; j
++)
6173 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6174 printk(KERN_CONT
"\n");
6176 printk(KERN_WARNING
"\n");
6179 static bool find_numa_distance(int distance
)
6183 if (distance
== node_distance(0, 0))
6186 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6187 if (sched_domains_numa_distance
[i
] == distance
)
6194 static void sched_init_numa(void)
6196 int next_distance
, curr_distance
= node_distance(0, 0);
6197 struct sched_domain_topology_level
*tl
;
6201 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6202 if (!sched_domains_numa_distance
)
6206 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6207 * unique distances in the node_distance() table.
6209 * Assumes node_distance(0,j) includes all distances in
6210 * node_distance(i,j) in order to avoid cubic time.
6212 next_distance
= curr_distance
;
6213 for (i
= 0; i
< nr_node_ids
; i
++) {
6214 for (j
= 0; j
< nr_node_ids
; j
++) {
6215 for (k
= 0; k
< nr_node_ids
; k
++) {
6216 int distance
= node_distance(i
, k
);
6218 if (distance
> curr_distance
&&
6219 (distance
< next_distance
||
6220 next_distance
== curr_distance
))
6221 next_distance
= distance
;
6224 * While not a strong assumption it would be nice to know
6225 * about cases where if node A is connected to B, B is not
6226 * equally connected to A.
6228 if (sched_debug() && node_distance(k
, i
) != distance
)
6229 sched_numa_warn("Node-distance not symmetric");
6231 if (sched_debug() && i
&& !find_numa_distance(distance
))
6232 sched_numa_warn("Node-0 not representative");
6234 if (next_distance
!= curr_distance
) {
6235 sched_domains_numa_distance
[level
++] = next_distance
;
6236 sched_domains_numa_levels
= level
;
6237 curr_distance
= next_distance
;
6242 * In case of sched_debug() we verify the above assumption.
6248 * 'level' contains the number of unique distances, excluding the
6249 * identity distance node_distance(i,i).
6251 * The sched_domains_numa_distance[] array includes the actual distance
6256 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6257 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6258 * the array will contain less then 'level' members. This could be
6259 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6260 * in other functions.
6262 * We reset it to 'level' at the end of this function.
6264 sched_domains_numa_levels
= 0;
6266 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6267 if (!sched_domains_numa_masks
)
6271 * Now for each level, construct a mask per node which contains all
6272 * cpus of nodes that are that many hops away from us.
6274 for (i
= 0; i
< level
; i
++) {
6275 sched_domains_numa_masks
[i
] =
6276 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6277 if (!sched_domains_numa_masks
[i
])
6280 for (j
= 0; j
< nr_node_ids
; j
++) {
6281 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6285 sched_domains_numa_masks
[i
][j
] = mask
;
6287 for (k
= 0; k
< nr_node_ids
; k
++) {
6288 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6291 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6296 /* Compute default topology size */
6297 for (i
= 0; sched_domain_topology
[i
].mask
; i
++);
6299 tl
= kzalloc((i
+ level
+ 1) *
6300 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6305 * Copy the default topology bits..
6307 for (i
= 0; sched_domain_topology
[i
].mask
; i
++)
6308 tl
[i
] = sched_domain_topology
[i
];
6311 * .. and append 'j' levels of NUMA goodness.
6313 for (j
= 0; j
< level
; i
++, j
++) {
6314 tl
[i
] = (struct sched_domain_topology_level
){
6315 .mask
= sd_numa_mask
,
6316 .sd_flags
= cpu_numa_flags
,
6317 .flags
= SDTL_OVERLAP
,
6323 sched_domain_topology
= tl
;
6325 sched_domains_numa_levels
= level
;
6328 static void sched_domains_numa_masks_set(int cpu
)
6331 int node
= cpu_to_node(cpu
);
6333 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6334 for (j
= 0; j
< nr_node_ids
; j
++) {
6335 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6336 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6341 static void sched_domains_numa_masks_clear(int cpu
)
6344 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6345 for (j
= 0; j
< nr_node_ids
; j
++)
6346 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6351 * Update sched_domains_numa_masks[level][node] array when new cpus
6354 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6355 unsigned long action
,
6358 int cpu
= (long)hcpu
;
6360 switch (action
& ~CPU_TASKS_FROZEN
) {
6362 sched_domains_numa_masks_set(cpu
);
6366 sched_domains_numa_masks_clear(cpu
);
6376 static inline void sched_init_numa(void)
6380 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6381 unsigned long action
,
6386 #endif /* CONFIG_NUMA */
6388 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6390 struct sched_domain_topology_level
*tl
;
6393 for_each_sd_topology(tl
) {
6394 struct sd_data
*sdd
= &tl
->data
;
6396 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6400 sdd
->sg
= alloc_percpu(struct sched_group
*);
6404 sdd
->sgc
= alloc_percpu(struct sched_group_capacity
*);
6408 for_each_cpu(j
, cpu_map
) {
6409 struct sched_domain
*sd
;
6410 struct sched_group
*sg
;
6411 struct sched_group_capacity
*sgc
;
6413 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6414 GFP_KERNEL
, cpu_to_node(j
));
6418 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6420 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6421 GFP_KERNEL
, cpu_to_node(j
));
6427 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6429 sgc
= kzalloc_node(sizeof(struct sched_group_capacity
) + cpumask_size(),
6430 GFP_KERNEL
, cpu_to_node(j
));
6434 *per_cpu_ptr(sdd
->sgc
, j
) = sgc
;
6441 static void __sdt_free(const struct cpumask
*cpu_map
)
6443 struct sched_domain_topology_level
*tl
;
6446 for_each_sd_topology(tl
) {
6447 struct sd_data
*sdd
= &tl
->data
;
6449 for_each_cpu(j
, cpu_map
) {
6450 struct sched_domain
*sd
;
6453 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6454 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6455 free_sched_groups(sd
->groups
, 0);
6456 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6460 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6462 kfree(*per_cpu_ptr(sdd
->sgc
, j
));
6464 free_percpu(sdd
->sd
);
6466 free_percpu(sdd
->sg
);
6468 free_percpu(sdd
->sgc
);
6473 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6474 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6475 struct sched_domain
*child
, int cpu
)
6477 struct sched_domain
*sd
= sd_init(tl
, cpu
);
6481 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6483 sd
->level
= child
->level
+ 1;
6484 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6488 if (!cpumask_subset(sched_domain_span(child
),
6489 sched_domain_span(sd
))) {
6490 pr_err("BUG: arch topology borken\n");
6491 #ifdef CONFIG_SCHED_DEBUG
6492 pr_err(" the %s domain not a subset of the %s domain\n",
6493 child
->name
, sd
->name
);
6495 /* Fixup, ensure @sd has at least @child cpus. */
6496 cpumask_or(sched_domain_span(sd
),
6497 sched_domain_span(sd
),
6498 sched_domain_span(child
));
6502 set_domain_attribute(sd
, attr
);
6508 * Build sched domains for a given set of cpus and attach the sched domains
6509 * to the individual cpus
6511 static int build_sched_domains(const struct cpumask
*cpu_map
,
6512 struct sched_domain_attr
*attr
)
6514 enum s_alloc alloc_state
;
6515 struct sched_domain
*sd
;
6517 int i
, ret
= -ENOMEM
;
6519 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6520 if (alloc_state
!= sa_rootdomain
)
6523 /* Set up domains for cpus specified by the cpu_map. */
6524 for_each_cpu(i
, cpu_map
) {
6525 struct sched_domain_topology_level
*tl
;
6528 for_each_sd_topology(tl
) {
6529 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6530 if (tl
== sched_domain_topology
)
6531 *per_cpu_ptr(d
.sd
, i
) = sd
;
6532 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6533 sd
->flags
|= SD_OVERLAP
;
6534 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6539 /* Build the groups for the domains */
6540 for_each_cpu(i
, cpu_map
) {
6541 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6542 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6543 if (sd
->flags
& SD_OVERLAP
) {
6544 if (build_overlap_sched_groups(sd
, i
))
6547 if (build_sched_groups(sd
, i
))
6553 /* Calculate CPU capacity for physical packages and nodes */
6554 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6555 if (!cpumask_test_cpu(i
, cpu_map
))
6558 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6559 claim_allocations(i
, sd
);
6560 init_sched_groups_capacity(i
, sd
);
6564 /* Attach the domains */
6566 for_each_cpu(i
, cpu_map
) {
6567 sd
= *per_cpu_ptr(d
.sd
, i
);
6568 cpu_attach_domain(sd
, d
.rd
, i
);
6574 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6578 static cpumask_var_t
*doms_cur
; /* current sched domains */
6579 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6580 static struct sched_domain_attr
*dattr_cur
;
6581 /* attribues of custom domains in 'doms_cur' */
6584 * Special case: If a kmalloc of a doms_cur partition (array of
6585 * cpumask) fails, then fallback to a single sched domain,
6586 * as determined by the single cpumask fallback_doms.
6588 static cpumask_var_t fallback_doms
;
6591 * arch_update_cpu_topology lets virtualized architectures update the
6592 * cpu core maps. It is supposed to return 1 if the topology changed
6593 * or 0 if it stayed the same.
6595 int __weak
arch_update_cpu_topology(void)
6600 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6603 cpumask_var_t
*doms
;
6605 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6608 for (i
= 0; i
< ndoms
; i
++) {
6609 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6610 free_sched_domains(doms
, i
);
6617 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6620 for (i
= 0; i
< ndoms
; i
++)
6621 free_cpumask_var(doms
[i
]);
6626 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6627 * For now this just excludes isolated cpus, but could be used to
6628 * exclude other special cases in the future.
6630 static int init_sched_domains(const struct cpumask
*cpu_map
)
6634 arch_update_cpu_topology();
6636 doms_cur
= alloc_sched_domains(ndoms_cur
);
6638 doms_cur
= &fallback_doms
;
6639 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6640 err
= build_sched_domains(doms_cur
[0], NULL
);
6641 register_sched_domain_sysctl();
6647 * Detach sched domains from a group of cpus specified in cpu_map
6648 * These cpus will now be attached to the NULL domain
6650 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6655 for_each_cpu(i
, cpu_map
)
6656 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6660 /* handle null as "default" */
6661 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6662 struct sched_domain_attr
*new, int idx_new
)
6664 struct sched_domain_attr tmp
;
6671 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6672 new ? (new + idx_new
) : &tmp
,
6673 sizeof(struct sched_domain_attr
));
6677 * Partition sched domains as specified by the 'ndoms_new'
6678 * cpumasks in the array doms_new[] of cpumasks. This compares
6679 * doms_new[] to the current sched domain partitioning, doms_cur[].
6680 * It destroys each deleted domain and builds each new domain.
6682 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6683 * The masks don't intersect (don't overlap.) We should setup one
6684 * sched domain for each mask. CPUs not in any of the cpumasks will
6685 * not be load balanced. If the same cpumask appears both in the
6686 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6689 * The passed in 'doms_new' should be allocated using
6690 * alloc_sched_domains. This routine takes ownership of it and will
6691 * free_sched_domains it when done with it. If the caller failed the
6692 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6693 * and partition_sched_domains() will fallback to the single partition
6694 * 'fallback_doms', it also forces the domains to be rebuilt.
6696 * If doms_new == NULL it will be replaced with cpu_online_mask.
6697 * ndoms_new == 0 is a special case for destroying existing domains,
6698 * and it will not create the default domain.
6700 * Call with hotplug lock held
6702 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6703 struct sched_domain_attr
*dattr_new
)
6708 mutex_lock(&sched_domains_mutex
);
6710 /* always unregister in case we don't destroy any domains */
6711 unregister_sched_domain_sysctl();
6713 /* Let architecture update cpu core mappings. */
6714 new_topology
= arch_update_cpu_topology();
6716 n
= doms_new
? ndoms_new
: 0;
6718 /* Destroy deleted domains */
6719 for (i
= 0; i
< ndoms_cur
; i
++) {
6720 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6721 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6722 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6725 /* no match - a current sched domain not in new doms_new[] */
6726 detach_destroy_domains(doms_cur
[i
]);
6732 if (doms_new
== NULL
) {
6734 doms_new
= &fallback_doms
;
6735 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6736 WARN_ON_ONCE(dattr_new
);
6739 /* Build new domains */
6740 for (i
= 0; i
< ndoms_new
; i
++) {
6741 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6742 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6743 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6746 /* no match - add a new doms_new */
6747 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6752 /* Remember the new sched domains */
6753 if (doms_cur
!= &fallback_doms
)
6754 free_sched_domains(doms_cur
, ndoms_cur
);
6755 kfree(dattr_cur
); /* kfree(NULL) is safe */
6756 doms_cur
= doms_new
;
6757 dattr_cur
= dattr_new
;
6758 ndoms_cur
= ndoms_new
;
6760 register_sched_domain_sysctl();
6762 mutex_unlock(&sched_domains_mutex
);
6765 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6768 * Update cpusets according to cpu_active mask. If cpusets are
6769 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6770 * around partition_sched_domains().
6772 * If we come here as part of a suspend/resume, don't touch cpusets because we
6773 * want to restore it back to its original state upon resume anyway.
6775 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6779 case CPU_ONLINE_FROZEN
:
6780 case CPU_DOWN_FAILED_FROZEN
:
6783 * num_cpus_frozen tracks how many CPUs are involved in suspend
6784 * resume sequence. As long as this is not the last online
6785 * operation in the resume sequence, just build a single sched
6786 * domain, ignoring cpusets.
6789 if (likely(num_cpus_frozen
)) {
6790 partition_sched_domains(1, NULL
, NULL
);
6795 * This is the last CPU online operation. So fall through and
6796 * restore the original sched domains by considering the
6797 * cpuset configurations.
6801 case CPU_DOWN_FAILED
:
6802 cpuset_update_active_cpus(true);
6810 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6814 case CPU_DOWN_PREPARE
:
6815 cpuset_update_active_cpus(false);
6817 case CPU_DOWN_PREPARE_FROZEN
:
6819 partition_sched_domains(1, NULL
, NULL
);
6827 void __init
sched_init_smp(void)
6829 cpumask_var_t non_isolated_cpus
;
6831 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
6832 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
6837 * There's no userspace yet to cause hotplug operations; hence all the
6838 * cpu masks are stable and all blatant races in the below code cannot
6841 mutex_lock(&sched_domains_mutex
);
6842 init_sched_domains(cpu_active_mask
);
6843 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
6844 if (cpumask_empty(non_isolated_cpus
))
6845 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
6846 mutex_unlock(&sched_domains_mutex
);
6848 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
6849 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
6850 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
6854 /* Move init over to a non-isolated CPU */
6855 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
6857 sched_init_granularity();
6858 free_cpumask_var(non_isolated_cpus
);
6860 init_sched_rt_class();
6861 init_sched_dl_class();
6864 void __init
sched_init_smp(void)
6866 sched_init_granularity();
6868 #endif /* CONFIG_SMP */
6870 const_debug
unsigned int sysctl_timer_migration
= 1;
6872 int in_sched_functions(unsigned long addr
)
6874 return in_lock_functions(addr
) ||
6875 (addr
>= (unsigned long)__sched_text_start
6876 && addr
< (unsigned long)__sched_text_end
);
6879 #ifdef CONFIG_CGROUP_SCHED
6881 * Default task group.
6882 * Every task in system belongs to this group at bootup.
6884 struct task_group root_task_group
;
6885 LIST_HEAD(task_groups
);
6888 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
6890 void __init
sched_init(void)
6893 unsigned long alloc_size
= 0, ptr
;
6895 #ifdef CONFIG_FAIR_GROUP_SCHED
6896 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6898 #ifdef CONFIG_RT_GROUP_SCHED
6899 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
6901 #ifdef CONFIG_CPUMASK_OFFSTACK
6902 alloc_size
+= num_possible_cpus() * cpumask_size();
6905 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
6907 #ifdef CONFIG_FAIR_GROUP_SCHED
6908 root_task_group
.se
= (struct sched_entity
**)ptr
;
6909 ptr
+= nr_cpu_ids
* sizeof(void **);
6911 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
6912 ptr
+= nr_cpu_ids
* sizeof(void **);
6914 #endif /* CONFIG_FAIR_GROUP_SCHED */
6915 #ifdef CONFIG_RT_GROUP_SCHED
6916 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
6917 ptr
+= nr_cpu_ids
* sizeof(void **);
6919 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
6920 ptr
+= nr_cpu_ids
* sizeof(void **);
6922 #endif /* CONFIG_RT_GROUP_SCHED */
6923 #ifdef CONFIG_CPUMASK_OFFSTACK
6924 for_each_possible_cpu(i
) {
6925 per_cpu(load_balance_mask
, i
) = (void *)ptr
;
6926 ptr
+= cpumask_size();
6928 #endif /* CONFIG_CPUMASK_OFFSTACK */
6931 init_rt_bandwidth(&def_rt_bandwidth
,
6932 global_rt_period(), global_rt_runtime());
6933 init_dl_bandwidth(&def_dl_bandwidth
,
6934 global_rt_period(), global_rt_runtime());
6937 init_defrootdomain();
6940 #ifdef CONFIG_RT_GROUP_SCHED
6941 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
6942 global_rt_period(), global_rt_runtime());
6943 #endif /* CONFIG_RT_GROUP_SCHED */
6945 #ifdef CONFIG_CGROUP_SCHED
6946 list_add(&root_task_group
.list
, &task_groups
);
6947 INIT_LIST_HEAD(&root_task_group
.children
);
6948 INIT_LIST_HEAD(&root_task_group
.siblings
);
6949 autogroup_init(&init_task
);
6951 #endif /* CONFIG_CGROUP_SCHED */
6953 for_each_possible_cpu(i
) {
6957 raw_spin_lock_init(&rq
->lock
);
6959 rq
->calc_load_active
= 0;
6960 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
6961 init_cfs_rq(&rq
->cfs
);
6962 init_rt_rq(&rq
->rt
, rq
);
6963 init_dl_rq(&rq
->dl
, rq
);
6964 #ifdef CONFIG_FAIR_GROUP_SCHED
6965 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
6966 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
6968 * How much cpu bandwidth does root_task_group get?
6970 * In case of task-groups formed thr' the cgroup filesystem, it
6971 * gets 100% of the cpu resources in the system. This overall
6972 * system cpu resource is divided among the tasks of
6973 * root_task_group and its child task-groups in a fair manner,
6974 * based on each entity's (task or task-group's) weight
6975 * (se->load.weight).
6977 * In other words, if root_task_group has 10 tasks of weight
6978 * 1024) and two child groups A0 and A1 (of weight 1024 each),
6979 * then A0's share of the cpu resource is:
6981 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
6983 * We achieve this by letting root_task_group's tasks sit
6984 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
6986 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
6987 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
6988 #endif /* CONFIG_FAIR_GROUP_SCHED */
6990 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
6991 #ifdef CONFIG_RT_GROUP_SCHED
6992 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
6995 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
6996 rq
->cpu_load
[j
] = 0;
6998 rq
->last_load_update_tick
= jiffies
;
7003 rq
->cpu_capacity
= SCHED_CAPACITY_SCALE
;
7004 rq
->post_schedule
= 0;
7005 rq
->active_balance
= 0;
7006 rq
->next_balance
= jiffies
;
7011 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7012 rq
->max_idle_balance_cost
= sysctl_sched_migration_cost
;
7014 INIT_LIST_HEAD(&rq
->cfs_tasks
);
7016 rq_attach_root(rq
, &def_root_domain
);
7017 #ifdef CONFIG_NO_HZ_COMMON
7020 #ifdef CONFIG_NO_HZ_FULL
7021 rq
->last_sched_tick
= 0;
7025 atomic_set(&rq
->nr_iowait
, 0);
7028 set_load_weight(&init_task
);
7030 #ifdef CONFIG_PREEMPT_NOTIFIERS
7031 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7035 * The boot idle thread does lazy MMU switching as well:
7037 atomic_inc(&init_mm
.mm_count
);
7038 enter_lazy_tlb(&init_mm
, current
);
7041 * Make us the idle thread. Technically, schedule() should not be
7042 * called from this thread, however somewhere below it might be,
7043 * but because we are the idle thread, we just pick up running again
7044 * when this runqueue becomes "idle".
7046 init_idle(current
, smp_processor_id());
7048 calc_load_update
= jiffies
+ LOAD_FREQ
;
7051 * During early bootup we pretend to be a normal task:
7053 current
->sched_class
= &fair_sched_class
;
7056 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
7057 /* May be allocated at isolcpus cmdline parse time */
7058 if (cpu_isolated_map
== NULL
)
7059 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7060 idle_thread_set_boot_cpu();
7061 set_cpu_rq_start_time();
7063 init_sched_fair_class();
7065 scheduler_running
= 1;
7068 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7069 static inline int preempt_count_equals(int preempt_offset
)
7071 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7073 return (nested
== preempt_offset
);
7076 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7078 static unsigned long prev_jiffy
; /* ratelimiting */
7080 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7081 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled() &&
7082 !is_idle_task(current
)) ||
7083 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7085 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7087 prev_jiffy
= jiffies
;
7090 "BUG: sleeping function called from invalid context at %s:%d\n",
7093 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7094 in_atomic(), irqs_disabled(),
7095 current
->pid
, current
->comm
);
7097 debug_show_held_locks(current
);
7098 if (irqs_disabled())
7099 print_irqtrace_events(current
);
7100 #ifdef CONFIG_DEBUG_PREEMPT
7101 if (!preempt_count_equals(preempt_offset
)) {
7102 pr_err("Preemption disabled at:");
7103 print_ip_sym(current
->preempt_disable_ip
);
7109 EXPORT_SYMBOL(__might_sleep
);
7112 #ifdef CONFIG_MAGIC_SYSRQ
7113 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7115 const struct sched_class
*prev_class
= p
->sched_class
;
7116 struct sched_attr attr
= {
7117 .sched_policy
= SCHED_NORMAL
,
7119 int old_prio
= p
->prio
;
7124 dequeue_task(rq
, p
, 0);
7125 __setscheduler(rq
, p
, &attr
);
7127 enqueue_task(rq
, p
, 0);
7131 check_class_changed(rq
, p
, prev_class
, old_prio
);
7134 void normalize_rt_tasks(void)
7136 struct task_struct
*g
, *p
;
7137 unsigned long flags
;
7140 read_lock_irqsave(&tasklist_lock
, flags
);
7141 do_each_thread(g
, p
) {
7143 * Only normalize user tasks:
7148 p
->se
.exec_start
= 0;
7149 #ifdef CONFIG_SCHEDSTATS
7150 p
->se
.statistics
.wait_start
= 0;
7151 p
->se
.statistics
.sleep_start
= 0;
7152 p
->se
.statistics
.block_start
= 0;
7155 if (!dl_task(p
) && !rt_task(p
)) {
7157 * Renice negative nice level userspace
7160 if (task_nice(p
) < 0 && p
->mm
)
7161 set_user_nice(p
, 0);
7165 raw_spin_lock(&p
->pi_lock
);
7166 rq
= __task_rq_lock(p
);
7168 normalize_task(rq
, p
);
7170 __task_rq_unlock(rq
);
7171 raw_spin_unlock(&p
->pi_lock
);
7172 } while_each_thread(g
, p
);
7174 read_unlock_irqrestore(&tasklist_lock
, flags
);
7177 #endif /* CONFIG_MAGIC_SYSRQ */
7179 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7181 * These functions are only useful for the IA64 MCA handling, or kdb.
7183 * They can only be called when the whole system has been
7184 * stopped - every CPU needs to be quiescent, and no scheduling
7185 * activity can take place. Using them for anything else would
7186 * be a serious bug, and as a result, they aren't even visible
7187 * under any other configuration.
7191 * curr_task - return the current task for a given cpu.
7192 * @cpu: the processor in question.
7194 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7196 * Return: The current task for @cpu.
7198 struct task_struct
*curr_task(int cpu
)
7200 return cpu_curr(cpu
);
7203 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7207 * set_curr_task - set the current task for a given cpu.
7208 * @cpu: the processor in question.
7209 * @p: the task pointer to set.
7211 * Description: This function must only be used when non-maskable interrupts
7212 * are serviced on a separate stack. It allows the architecture to switch the
7213 * notion of the current task on a cpu in a non-blocking manner. This function
7214 * must be called with all CPU's synchronized, and interrupts disabled, the
7215 * and caller must save the original value of the current task (see
7216 * curr_task() above) and restore that value before reenabling interrupts and
7217 * re-starting the system.
7219 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7221 void set_curr_task(int cpu
, struct task_struct
*p
)
7228 #ifdef CONFIG_CGROUP_SCHED
7229 /* task_group_lock serializes the addition/removal of task groups */
7230 static DEFINE_SPINLOCK(task_group_lock
);
7232 static void free_sched_group(struct task_group
*tg
)
7234 free_fair_sched_group(tg
);
7235 free_rt_sched_group(tg
);
7240 /* allocate runqueue etc for a new task group */
7241 struct task_group
*sched_create_group(struct task_group
*parent
)
7243 struct task_group
*tg
;
7245 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7247 return ERR_PTR(-ENOMEM
);
7249 if (!alloc_fair_sched_group(tg
, parent
))
7252 if (!alloc_rt_sched_group(tg
, parent
))
7258 free_sched_group(tg
);
7259 return ERR_PTR(-ENOMEM
);
7262 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
7264 unsigned long flags
;
7266 spin_lock_irqsave(&task_group_lock
, flags
);
7267 list_add_rcu(&tg
->list
, &task_groups
);
7269 WARN_ON(!parent
); /* root should already exist */
7271 tg
->parent
= parent
;
7272 INIT_LIST_HEAD(&tg
->children
);
7273 list_add_rcu(&tg
->siblings
, &parent
->children
);
7274 spin_unlock_irqrestore(&task_group_lock
, flags
);
7277 /* rcu callback to free various structures associated with a task group */
7278 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7280 /* now it should be safe to free those cfs_rqs */
7281 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7284 /* Destroy runqueue etc associated with a task group */
7285 void sched_destroy_group(struct task_group
*tg
)
7287 /* wait for possible concurrent references to cfs_rqs complete */
7288 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7291 void sched_offline_group(struct task_group
*tg
)
7293 unsigned long flags
;
7296 /* end participation in shares distribution */
7297 for_each_possible_cpu(i
)
7298 unregister_fair_sched_group(tg
, i
);
7300 spin_lock_irqsave(&task_group_lock
, flags
);
7301 list_del_rcu(&tg
->list
);
7302 list_del_rcu(&tg
->siblings
);
7303 spin_unlock_irqrestore(&task_group_lock
, flags
);
7306 /* change task's runqueue when it moves between groups.
7307 * The caller of this function should have put the task in its new group
7308 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7309 * reflect its new group.
7311 void sched_move_task(struct task_struct
*tsk
)
7313 struct task_group
*tg
;
7315 unsigned long flags
;
7318 rq
= task_rq_lock(tsk
, &flags
);
7320 running
= task_current(rq
, tsk
);
7324 dequeue_task(rq
, tsk
, 0);
7325 if (unlikely(running
))
7326 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7328 tg
= container_of(task_css_check(tsk
, cpu_cgrp_id
,
7329 lockdep_is_held(&tsk
->sighand
->siglock
)),
7330 struct task_group
, css
);
7331 tg
= autogroup_task_group(tsk
, tg
);
7332 tsk
->sched_task_group
= tg
;
7334 #ifdef CONFIG_FAIR_GROUP_SCHED
7335 if (tsk
->sched_class
->task_move_group
)
7336 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
7339 set_task_rq(tsk
, task_cpu(tsk
));
7341 if (unlikely(running
))
7342 tsk
->sched_class
->set_curr_task(rq
);
7344 enqueue_task(rq
, tsk
, 0);
7346 task_rq_unlock(rq
, tsk
, &flags
);
7348 #endif /* CONFIG_CGROUP_SCHED */
7350 #ifdef CONFIG_RT_GROUP_SCHED
7352 * Ensure that the real time constraints are schedulable.
7354 static DEFINE_MUTEX(rt_constraints_mutex
);
7356 /* Must be called with tasklist_lock held */
7357 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7359 struct task_struct
*g
, *p
;
7361 do_each_thread(g
, p
) {
7362 if (rt_task(p
) && task_rq(p
)->rt
.tg
== tg
)
7364 } while_each_thread(g
, p
);
7369 struct rt_schedulable_data
{
7370 struct task_group
*tg
;
7375 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7377 struct rt_schedulable_data
*d
= data
;
7378 struct task_group
*child
;
7379 unsigned long total
, sum
= 0;
7380 u64 period
, runtime
;
7382 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7383 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7386 period
= d
->rt_period
;
7387 runtime
= d
->rt_runtime
;
7391 * Cannot have more runtime than the period.
7393 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7397 * Ensure we don't starve existing RT tasks.
7399 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7402 total
= to_ratio(period
, runtime
);
7405 * Nobody can have more than the global setting allows.
7407 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7411 * The sum of our children's runtime should not exceed our own.
7413 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7414 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7415 runtime
= child
->rt_bandwidth
.rt_runtime
;
7417 if (child
== d
->tg
) {
7418 period
= d
->rt_period
;
7419 runtime
= d
->rt_runtime
;
7422 sum
+= to_ratio(period
, runtime
);
7431 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7435 struct rt_schedulable_data data
= {
7437 .rt_period
= period
,
7438 .rt_runtime
= runtime
,
7442 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7448 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7449 u64 rt_period
, u64 rt_runtime
)
7453 mutex_lock(&rt_constraints_mutex
);
7454 read_lock(&tasklist_lock
);
7455 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7459 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7460 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7461 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7463 for_each_possible_cpu(i
) {
7464 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7466 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7467 rt_rq
->rt_runtime
= rt_runtime
;
7468 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7470 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7472 read_unlock(&tasklist_lock
);
7473 mutex_unlock(&rt_constraints_mutex
);
7478 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7480 u64 rt_runtime
, rt_period
;
7482 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7483 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7484 if (rt_runtime_us
< 0)
7485 rt_runtime
= RUNTIME_INF
;
7487 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7490 static long sched_group_rt_runtime(struct task_group
*tg
)
7494 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7497 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7498 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7499 return rt_runtime_us
;
7502 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7504 u64 rt_runtime
, rt_period
;
7506 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7507 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7512 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7515 static long sched_group_rt_period(struct task_group
*tg
)
7519 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7520 do_div(rt_period_us
, NSEC_PER_USEC
);
7521 return rt_period_us
;
7523 #endif /* CONFIG_RT_GROUP_SCHED */
7525 #ifdef CONFIG_RT_GROUP_SCHED
7526 static int sched_rt_global_constraints(void)
7530 mutex_lock(&rt_constraints_mutex
);
7531 read_lock(&tasklist_lock
);
7532 ret
= __rt_schedulable(NULL
, 0, 0);
7533 read_unlock(&tasklist_lock
);
7534 mutex_unlock(&rt_constraints_mutex
);
7539 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7541 /* Don't accept realtime tasks when there is no way for them to run */
7542 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7548 #else /* !CONFIG_RT_GROUP_SCHED */
7549 static int sched_rt_global_constraints(void)
7551 unsigned long flags
;
7554 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7555 for_each_possible_cpu(i
) {
7556 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7558 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7559 rt_rq
->rt_runtime
= global_rt_runtime();
7560 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7562 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7566 #endif /* CONFIG_RT_GROUP_SCHED */
7568 static int sched_dl_global_constraints(void)
7570 u64 runtime
= global_rt_runtime();
7571 u64 period
= global_rt_period();
7572 u64 new_bw
= to_ratio(period
, runtime
);
7574 unsigned long flags
;
7577 * Here we want to check the bandwidth not being set to some
7578 * value smaller than the currently allocated bandwidth in
7579 * any of the root_domains.
7581 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7582 * cycling on root_domains... Discussion on different/better
7583 * solutions is welcome!
7585 for_each_possible_cpu(cpu
) {
7586 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
7588 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7589 if (new_bw
< dl_b
->total_bw
)
7591 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7600 static void sched_dl_do_global(void)
7604 unsigned long flags
;
7606 def_dl_bandwidth
.dl_period
= global_rt_period();
7607 def_dl_bandwidth
.dl_runtime
= global_rt_runtime();
7609 if (global_rt_runtime() != RUNTIME_INF
)
7610 new_bw
= to_ratio(global_rt_period(), global_rt_runtime());
7613 * FIXME: As above...
7615 for_each_possible_cpu(cpu
) {
7616 struct dl_bw
*dl_b
= dl_bw_of(cpu
);
7618 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7620 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7624 static int sched_rt_global_validate(void)
7626 if (sysctl_sched_rt_period
<= 0)
7629 if ((sysctl_sched_rt_runtime
!= RUNTIME_INF
) &&
7630 (sysctl_sched_rt_runtime
> sysctl_sched_rt_period
))
7636 static void sched_rt_do_global(void)
7638 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7639 def_rt_bandwidth
.rt_period
= ns_to_ktime(global_rt_period());
7642 int sched_rt_handler(struct ctl_table
*table
, int write
,
7643 void __user
*buffer
, size_t *lenp
,
7646 int old_period
, old_runtime
;
7647 static DEFINE_MUTEX(mutex
);
7651 old_period
= sysctl_sched_rt_period
;
7652 old_runtime
= sysctl_sched_rt_runtime
;
7654 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7656 if (!ret
&& write
) {
7657 ret
= sched_rt_global_validate();
7661 ret
= sched_rt_global_constraints();
7665 ret
= sched_dl_global_constraints();
7669 sched_rt_do_global();
7670 sched_dl_do_global();
7674 sysctl_sched_rt_period
= old_period
;
7675 sysctl_sched_rt_runtime
= old_runtime
;
7677 mutex_unlock(&mutex
);
7682 int sched_rr_handler(struct ctl_table
*table
, int write
,
7683 void __user
*buffer
, size_t *lenp
,
7687 static DEFINE_MUTEX(mutex
);
7690 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7691 /* make sure that internally we keep jiffies */
7692 /* also, writing zero resets timeslice to default */
7693 if (!ret
&& write
) {
7694 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7695 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7697 mutex_unlock(&mutex
);
7701 #ifdef CONFIG_CGROUP_SCHED
7703 static inline struct task_group
*css_tg(struct cgroup_subsys_state
*css
)
7705 return css
? container_of(css
, struct task_group
, css
) : NULL
;
7708 static struct cgroup_subsys_state
*
7709 cpu_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
7711 struct task_group
*parent
= css_tg(parent_css
);
7712 struct task_group
*tg
;
7715 /* This is early initialization for the top cgroup */
7716 return &root_task_group
.css
;
7719 tg
= sched_create_group(parent
);
7721 return ERR_PTR(-ENOMEM
);
7726 static int cpu_cgroup_css_online(struct cgroup_subsys_state
*css
)
7728 struct task_group
*tg
= css_tg(css
);
7729 struct task_group
*parent
= css_tg(css
->parent
);
7732 sched_online_group(tg
, parent
);
7736 static void cpu_cgroup_css_free(struct cgroup_subsys_state
*css
)
7738 struct task_group
*tg
= css_tg(css
);
7740 sched_destroy_group(tg
);
7743 static void cpu_cgroup_css_offline(struct cgroup_subsys_state
*css
)
7745 struct task_group
*tg
= css_tg(css
);
7747 sched_offline_group(tg
);
7750 static int cpu_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7751 struct cgroup_taskset
*tset
)
7753 struct task_struct
*task
;
7755 cgroup_taskset_for_each(task
, tset
) {
7756 #ifdef CONFIG_RT_GROUP_SCHED
7757 if (!sched_rt_can_attach(css_tg(css
), task
))
7760 /* We don't support RT-tasks being in separate groups */
7761 if (task
->sched_class
!= &fair_sched_class
)
7768 static void cpu_cgroup_attach(struct cgroup_subsys_state
*css
,
7769 struct cgroup_taskset
*tset
)
7771 struct task_struct
*task
;
7773 cgroup_taskset_for_each(task
, tset
)
7774 sched_move_task(task
);
7777 static void cpu_cgroup_exit(struct cgroup_subsys_state
*css
,
7778 struct cgroup_subsys_state
*old_css
,
7779 struct task_struct
*task
)
7782 * cgroup_exit() is called in the copy_process() failure path.
7783 * Ignore this case since the task hasn't ran yet, this avoids
7784 * trying to poke a half freed task state from generic code.
7786 if (!(task
->flags
& PF_EXITING
))
7789 sched_move_task(task
);
7792 #ifdef CONFIG_FAIR_GROUP_SCHED
7793 static int cpu_shares_write_u64(struct cgroup_subsys_state
*css
,
7794 struct cftype
*cftype
, u64 shareval
)
7796 return sched_group_set_shares(css_tg(css
), scale_load(shareval
));
7799 static u64
cpu_shares_read_u64(struct cgroup_subsys_state
*css
,
7802 struct task_group
*tg
= css_tg(css
);
7804 return (u64
) scale_load_down(tg
->shares
);
7807 #ifdef CONFIG_CFS_BANDWIDTH
7808 static DEFINE_MUTEX(cfs_constraints_mutex
);
7810 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
7811 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
7813 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
7815 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
7817 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
7818 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7820 if (tg
== &root_task_group
)
7824 * Ensure we have at some amount of bandwidth every period. This is
7825 * to prevent reaching a state of large arrears when throttled via
7826 * entity_tick() resulting in prolonged exit starvation.
7828 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
7832 * Likewise, bound things on the otherside by preventing insane quota
7833 * periods. This also allows us to normalize in computing quota
7836 if (period
> max_cfs_quota_period
)
7840 * Prevent race between setting of cfs_rq->runtime_enabled and
7841 * unthrottle_offline_cfs_rqs().
7844 mutex_lock(&cfs_constraints_mutex
);
7845 ret
= __cfs_schedulable(tg
, period
, quota
);
7849 runtime_enabled
= quota
!= RUNTIME_INF
;
7850 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
7852 * If we need to toggle cfs_bandwidth_used, off->on must occur
7853 * before making related changes, and on->off must occur afterwards
7855 if (runtime_enabled
&& !runtime_was_enabled
)
7856 cfs_bandwidth_usage_inc();
7857 raw_spin_lock_irq(&cfs_b
->lock
);
7858 cfs_b
->period
= ns_to_ktime(period
);
7859 cfs_b
->quota
= quota
;
7861 __refill_cfs_bandwidth_runtime(cfs_b
);
7862 /* restart the period timer (if active) to handle new period expiry */
7863 if (runtime_enabled
&& cfs_b
->timer_active
) {
7864 /* force a reprogram */
7865 __start_cfs_bandwidth(cfs_b
, true);
7867 raw_spin_unlock_irq(&cfs_b
->lock
);
7869 for_each_online_cpu(i
) {
7870 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
7871 struct rq
*rq
= cfs_rq
->rq
;
7873 raw_spin_lock_irq(&rq
->lock
);
7874 cfs_rq
->runtime_enabled
= runtime_enabled
;
7875 cfs_rq
->runtime_remaining
= 0;
7877 if (cfs_rq
->throttled
)
7878 unthrottle_cfs_rq(cfs_rq
);
7879 raw_spin_unlock_irq(&rq
->lock
);
7881 if (runtime_was_enabled
&& !runtime_enabled
)
7882 cfs_bandwidth_usage_dec();
7884 mutex_unlock(&cfs_constraints_mutex
);
7890 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
7894 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7895 if (cfs_quota_us
< 0)
7896 quota
= RUNTIME_INF
;
7898 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
7900 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7903 long tg_get_cfs_quota(struct task_group
*tg
)
7907 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
7910 quota_us
= tg
->cfs_bandwidth
.quota
;
7911 do_div(quota_us
, NSEC_PER_USEC
);
7916 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
7920 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
7921 quota
= tg
->cfs_bandwidth
.quota
;
7923 return tg_set_cfs_bandwidth(tg
, period
, quota
);
7926 long tg_get_cfs_period(struct task_group
*tg
)
7930 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
7931 do_div(cfs_period_us
, NSEC_PER_USEC
);
7933 return cfs_period_us
;
7936 static s64
cpu_cfs_quota_read_s64(struct cgroup_subsys_state
*css
,
7939 return tg_get_cfs_quota(css_tg(css
));
7942 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state
*css
,
7943 struct cftype
*cftype
, s64 cfs_quota_us
)
7945 return tg_set_cfs_quota(css_tg(css
), cfs_quota_us
);
7948 static u64
cpu_cfs_period_read_u64(struct cgroup_subsys_state
*css
,
7951 return tg_get_cfs_period(css_tg(css
));
7954 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state
*css
,
7955 struct cftype
*cftype
, u64 cfs_period_us
)
7957 return tg_set_cfs_period(css_tg(css
), cfs_period_us
);
7960 struct cfs_schedulable_data
{
7961 struct task_group
*tg
;
7966 * normalize group quota/period to be quota/max_period
7967 * note: units are usecs
7969 static u64
normalize_cfs_quota(struct task_group
*tg
,
7970 struct cfs_schedulable_data
*d
)
7978 period
= tg_get_cfs_period(tg
);
7979 quota
= tg_get_cfs_quota(tg
);
7982 /* note: these should typically be equivalent */
7983 if (quota
== RUNTIME_INF
|| quota
== -1)
7986 return to_ratio(period
, quota
);
7989 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
7991 struct cfs_schedulable_data
*d
= data
;
7992 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
7993 s64 quota
= 0, parent_quota
= -1;
7996 quota
= RUNTIME_INF
;
7998 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
8000 quota
= normalize_cfs_quota(tg
, d
);
8001 parent_quota
= parent_b
->hierarchal_quota
;
8004 * ensure max(child_quota) <= parent_quota, inherit when no
8007 if (quota
== RUNTIME_INF
)
8008 quota
= parent_quota
;
8009 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
8012 cfs_b
->hierarchal_quota
= quota
;
8017 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
8020 struct cfs_schedulable_data data
= {
8026 if (quota
!= RUNTIME_INF
) {
8027 do_div(data
.period
, NSEC_PER_USEC
);
8028 do_div(data
.quota
, NSEC_PER_USEC
);
8032 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
8038 static int cpu_stats_show(struct seq_file
*sf
, void *v
)
8040 struct task_group
*tg
= css_tg(seq_css(sf
));
8041 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8043 seq_printf(sf
, "nr_periods %d\n", cfs_b
->nr_periods
);
8044 seq_printf(sf
, "nr_throttled %d\n", cfs_b
->nr_throttled
);
8045 seq_printf(sf
, "throttled_time %llu\n", cfs_b
->throttled_time
);
8049 #endif /* CONFIG_CFS_BANDWIDTH */
8050 #endif /* CONFIG_FAIR_GROUP_SCHED */
8052 #ifdef CONFIG_RT_GROUP_SCHED
8053 static int cpu_rt_runtime_write(struct cgroup_subsys_state
*css
,
8054 struct cftype
*cft
, s64 val
)
8056 return sched_group_set_rt_runtime(css_tg(css
), val
);
8059 static s64
cpu_rt_runtime_read(struct cgroup_subsys_state
*css
,
8062 return sched_group_rt_runtime(css_tg(css
));
8065 static int cpu_rt_period_write_uint(struct cgroup_subsys_state
*css
,
8066 struct cftype
*cftype
, u64 rt_period_us
)
8068 return sched_group_set_rt_period(css_tg(css
), rt_period_us
);
8071 static u64
cpu_rt_period_read_uint(struct cgroup_subsys_state
*css
,
8074 return sched_group_rt_period(css_tg(css
));
8076 #endif /* CONFIG_RT_GROUP_SCHED */
8078 static struct cftype cpu_files
[] = {
8079 #ifdef CONFIG_FAIR_GROUP_SCHED
8082 .read_u64
= cpu_shares_read_u64
,
8083 .write_u64
= cpu_shares_write_u64
,
8086 #ifdef CONFIG_CFS_BANDWIDTH
8088 .name
= "cfs_quota_us",
8089 .read_s64
= cpu_cfs_quota_read_s64
,
8090 .write_s64
= cpu_cfs_quota_write_s64
,
8093 .name
= "cfs_period_us",
8094 .read_u64
= cpu_cfs_period_read_u64
,
8095 .write_u64
= cpu_cfs_period_write_u64
,
8099 .seq_show
= cpu_stats_show
,
8102 #ifdef CONFIG_RT_GROUP_SCHED
8104 .name
= "rt_runtime_us",
8105 .read_s64
= cpu_rt_runtime_read
,
8106 .write_s64
= cpu_rt_runtime_write
,
8109 .name
= "rt_period_us",
8110 .read_u64
= cpu_rt_period_read_uint
,
8111 .write_u64
= cpu_rt_period_write_uint
,
8117 struct cgroup_subsys cpu_cgrp_subsys
= {
8118 .css_alloc
= cpu_cgroup_css_alloc
,
8119 .css_free
= cpu_cgroup_css_free
,
8120 .css_online
= cpu_cgroup_css_online
,
8121 .css_offline
= cpu_cgroup_css_offline
,
8122 .can_attach
= cpu_cgroup_can_attach
,
8123 .attach
= cpu_cgroup_attach
,
8124 .exit
= cpu_cgroup_exit
,
8125 .legacy_cftypes
= cpu_files
,
8129 #endif /* CONFIG_CGROUP_SCHED */
8131 void dump_cpu_task(int cpu
)
8133 pr_info("Task dump for CPU %d:\n", cpu
);
8134 sched_show_task(cpu_curr(cpu
));