4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <asm/mmu_context.h>
36 #include <linux/interrupt.h>
37 #include <linux/capability.h>
38 #include <linux/completion.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/debug_locks.h>
41 #include <linux/perf_event.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/proc_fs.h>
58 #include <linux/seq_file.h>
59 #include <linux/sysctl.h>
60 #include <linux/syscalls.h>
61 #include <linux/times.h>
62 #include <linux/tsacct_kern.h>
63 #include <linux/kprobes.h>
64 #include <linux/delayacct.h>
65 #include <linux/unistd.h>
66 #include <linux/pagemap.h>
67 #include <linux/hrtimer.h>
68 #include <linux/tick.h>
69 #include <linux/debugfs.h>
70 #include <linux/ctype.h>
71 #include <linux/ftrace.h>
72 #include <linux/slab.h>
73 #include <linux/init_task.h>
74 #include <linux/binfmts.h>
75 #include <linux/context_tracking.h>
76 #include <linux/compiler.h>
78 #include <asm/switch_to.h>
80 #include <asm/irq_regs.h>
81 #include <asm/mutex.h>
82 #ifdef CONFIG_PARAVIRT
83 #include <asm/paravirt.h>
87 #include "../workqueue_internal.h"
88 #include "../smpboot.h"
90 #define CREATE_TRACE_POINTS
91 #include <trace/events/sched.h>
93 void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
96 ktime_t soft
, hard
, now
;
99 if (hrtimer_active(period_timer
))
102 now
= hrtimer_cb_get_time(period_timer
);
103 hrtimer_forward(period_timer
, now
, period
);
105 soft
= hrtimer_get_softexpires(period_timer
);
106 hard
= hrtimer_get_expires(period_timer
);
107 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
108 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
109 HRTIMER_MODE_ABS_PINNED
, 0);
113 DEFINE_MUTEX(sched_domains_mutex
);
114 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
116 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
118 void update_rq_clock(struct rq
*rq
)
122 lockdep_assert_held(&rq
->lock
);
124 if (rq
->clock_skip_update
& RQCF_ACT_SKIP
)
127 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
131 update_rq_clock_task(rq
, delta
);
135 * Debugging: various feature bits
138 #define SCHED_FEAT(name, enabled) \
139 (1UL << __SCHED_FEAT_##name) * enabled |
141 const_debug
unsigned int sysctl_sched_features
=
142 #include "features.h"
147 #ifdef CONFIG_SCHED_DEBUG
148 #define SCHED_FEAT(name, enabled) \
151 static const char * const sched_feat_names
[] = {
152 #include "features.h"
157 static int sched_feat_show(struct seq_file
*m
, void *v
)
161 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
162 if (!(sysctl_sched_features
& (1UL << i
)))
164 seq_printf(m
, "%s ", sched_feat_names
[i
]);
171 #ifdef HAVE_JUMP_LABEL
173 #define jump_label_key__true STATIC_KEY_INIT_TRUE
174 #define jump_label_key__false STATIC_KEY_INIT_FALSE
176 #define SCHED_FEAT(name, enabled) \
177 jump_label_key__##enabled ,
179 struct static_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
180 #include "features.h"
185 static void sched_feat_disable(int i
)
187 if (static_key_enabled(&sched_feat_keys
[i
]))
188 static_key_slow_dec(&sched_feat_keys
[i
]);
191 static void sched_feat_enable(int i
)
193 if (!static_key_enabled(&sched_feat_keys
[i
]))
194 static_key_slow_inc(&sched_feat_keys
[i
]);
197 static void sched_feat_disable(int i
) { };
198 static void sched_feat_enable(int i
) { };
199 #endif /* HAVE_JUMP_LABEL */
201 static int sched_feat_set(char *cmp
)
206 if (strncmp(cmp
, "NO_", 3) == 0) {
211 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
212 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
214 sysctl_sched_features
&= ~(1UL << i
);
215 sched_feat_disable(i
);
217 sysctl_sched_features
|= (1UL << i
);
218 sched_feat_enable(i
);
228 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
229 size_t cnt
, loff_t
*ppos
)
239 if (copy_from_user(&buf
, ubuf
, cnt
))
245 /* Ensure the static_key remains in a consistent state */
246 inode
= file_inode(filp
);
247 mutex_lock(&inode
->i_mutex
);
248 i
= sched_feat_set(cmp
);
249 mutex_unlock(&inode
->i_mutex
);
250 if (i
== __SCHED_FEAT_NR
)
258 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
260 return single_open(filp
, sched_feat_show
, NULL
);
263 static const struct file_operations sched_feat_fops
= {
264 .open
= sched_feat_open
,
265 .write
= sched_feat_write
,
268 .release
= single_release
,
271 static __init
int sched_init_debug(void)
273 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
278 late_initcall(sched_init_debug
);
279 #endif /* CONFIG_SCHED_DEBUG */
282 * Number of tasks to iterate in a single balance run.
283 * Limited because this is done with IRQs disabled.
285 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
288 * period over which we average the RT time consumption, measured
293 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
296 * period over which we measure -rt task cpu usage in us.
299 unsigned int sysctl_sched_rt_period
= 1000000;
301 __read_mostly
int scheduler_running
;
304 * part of the period that we allow rt tasks to run in us.
307 int sysctl_sched_rt_runtime
= 950000;
310 * this_rq_lock - lock this runqueue and disable interrupts.
312 static struct rq
*this_rq_lock(void)
319 raw_spin_lock(&rq
->lock
);
324 #ifdef CONFIG_SCHED_HRTICK
326 * Use HR-timers to deliver accurate preemption points.
329 static void hrtick_clear(struct rq
*rq
)
331 if (hrtimer_active(&rq
->hrtick_timer
))
332 hrtimer_cancel(&rq
->hrtick_timer
);
336 * High-resolution timer tick.
337 * Runs from hardirq context with interrupts disabled.
339 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
341 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
343 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
345 raw_spin_lock(&rq
->lock
);
347 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
348 raw_spin_unlock(&rq
->lock
);
350 return HRTIMER_NORESTART
;
355 static int __hrtick_restart(struct rq
*rq
)
357 struct hrtimer
*timer
= &rq
->hrtick_timer
;
358 ktime_t time
= hrtimer_get_softexpires(timer
);
360 return __hrtimer_start_range_ns(timer
, time
, 0, HRTIMER_MODE_ABS_PINNED
, 0);
364 * called from hardirq (IPI) context
366 static void __hrtick_start(void *arg
)
370 raw_spin_lock(&rq
->lock
);
371 __hrtick_restart(rq
);
372 rq
->hrtick_csd_pending
= 0;
373 raw_spin_unlock(&rq
->lock
);
377 * Called to set the hrtick timer state.
379 * called with rq->lock held and irqs disabled
381 void hrtick_start(struct rq
*rq
, u64 delay
)
383 struct hrtimer
*timer
= &rq
->hrtick_timer
;
388 * Don't schedule slices shorter than 10000ns, that just
389 * doesn't make sense and can cause timer DoS.
391 delta
= max_t(s64
, delay
, 10000LL);
392 time
= ktime_add_ns(timer
->base
->get_time(), delta
);
394 hrtimer_set_expires(timer
, time
);
396 if (rq
== this_rq()) {
397 __hrtick_restart(rq
);
398 } else if (!rq
->hrtick_csd_pending
) {
399 smp_call_function_single_async(cpu_of(rq
), &rq
->hrtick_csd
);
400 rq
->hrtick_csd_pending
= 1;
405 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
407 int cpu
= (int)(long)hcpu
;
410 case CPU_UP_CANCELED
:
411 case CPU_UP_CANCELED_FROZEN
:
412 case CPU_DOWN_PREPARE
:
413 case CPU_DOWN_PREPARE_FROZEN
:
415 case CPU_DEAD_FROZEN
:
416 hrtick_clear(cpu_rq(cpu
));
423 static __init
void init_hrtick(void)
425 hotcpu_notifier(hotplug_hrtick
, 0);
429 * Called to set the hrtick timer state.
431 * called with rq->lock held and irqs disabled
433 void hrtick_start(struct rq
*rq
, u64 delay
)
436 * Don't schedule slices shorter than 10000ns, that just
437 * doesn't make sense. Rely on vruntime for fairness.
439 delay
= max_t(u64
, delay
, 10000LL);
440 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
441 HRTIMER_MODE_REL_PINNED
, 0);
444 static inline void init_hrtick(void)
447 #endif /* CONFIG_SMP */
449 static void init_rq_hrtick(struct rq
*rq
)
452 rq
->hrtick_csd_pending
= 0;
454 rq
->hrtick_csd
.flags
= 0;
455 rq
->hrtick_csd
.func
= __hrtick_start
;
456 rq
->hrtick_csd
.info
= rq
;
459 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
460 rq
->hrtick_timer
.function
= hrtick
;
462 #else /* CONFIG_SCHED_HRTICK */
463 static inline void hrtick_clear(struct rq
*rq
)
467 static inline void init_rq_hrtick(struct rq
*rq
)
471 static inline void init_hrtick(void)
474 #endif /* CONFIG_SCHED_HRTICK */
477 * cmpxchg based fetch_or, macro so it works for different integer types
479 #define fetch_or(ptr, val) \
480 ({ typeof(*(ptr)) __old, __val = *(ptr); \
482 __old = cmpxchg((ptr), __val, __val | (val)); \
483 if (__old == __val) \
490 #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
492 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
493 * this avoids any races wrt polling state changes and thereby avoids
496 static bool set_nr_and_not_polling(struct task_struct
*p
)
498 struct thread_info
*ti
= task_thread_info(p
);
499 return !(fetch_or(&ti
->flags
, _TIF_NEED_RESCHED
) & _TIF_POLLING_NRFLAG
);
503 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
505 * If this returns true, then the idle task promises to call
506 * sched_ttwu_pending() and reschedule soon.
508 static bool set_nr_if_polling(struct task_struct
*p
)
510 struct thread_info
*ti
= task_thread_info(p
);
511 typeof(ti
->flags
) old
, val
= ACCESS_ONCE(ti
->flags
);
514 if (!(val
& _TIF_POLLING_NRFLAG
))
516 if (val
& _TIF_NEED_RESCHED
)
518 old
= cmpxchg(&ti
->flags
, val
, val
| _TIF_NEED_RESCHED
);
527 static bool set_nr_and_not_polling(struct task_struct
*p
)
529 set_tsk_need_resched(p
);
534 static bool set_nr_if_polling(struct task_struct
*p
)
542 * resched_curr - mark rq's current task 'to be rescheduled now'.
544 * On UP this means the setting of the need_resched flag, on SMP it
545 * might also involve a cross-CPU call to trigger the scheduler on
548 void resched_curr(struct rq
*rq
)
550 struct task_struct
*curr
= rq
->curr
;
553 lockdep_assert_held(&rq
->lock
);
555 if (test_tsk_need_resched(curr
))
560 if (cpu
== smp_processor_id()) {
561 set_tsk_need_resched(curr
);
562 set_preempt_need_resched();
566 if (set_nr_and_not_polling(curr
))
567 smp_send_reschedule(cpu
);
569 trace_sched_wake_idle_without_ipi(cpu
);
572 void resched_cpu(int cpu
)
574 struct rq
*rq
= cpu_rq(cpu
);
577 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
580 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
584 #ifdef CONFIG_NO_HZ_COMMON
586 * In the semi idle case, use the nearest busy cpu for migrating timers
587 * from an idle cpu. This is good for power-savings.
589 * We don't do similar optimization for completely idle system, as
590 * selecting an idle cpu will add more delays to the timers than intended
591 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
593 int get_nohz_timer_target(int pinned
)
595 int cpu
= smp_processor_id();
597 struct sched_domain
*sd
;
599 if (pinned
|| !get_sysctl_timer_migration() || !idle_cpu(cpu
))
603 for_each_domain(cpu
, sd
) {
604 for_each_cpu(i
, sched_domain_span(sd
)) {
616 * When add_timer_on() enqueues a timer into the timer wheel of an
617 * idle CPU then this timer might expire before the next timer event
618 * which is scheduled to wake up that CPU. In case of a completely
619 * idle system the next event might even be infinite time into the
620 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
621 * leaves the inner idle loop so the newly added timer is taken into
622 * account when the CPU goes back to idle and evaluates the timer
623 * wheel for the next timer event.
625 static void wake_up_idle_cpu(int cpu
)
627 struct rq
*rq
= cpu_rq(cpu
);
629 if (cpu
== smp_processor_id())
632 if (set_nr_and_not_polling(rq
->idle
))
633 smp_send_reschedule(cpu
);
635 trace_sched_wake_idle_without_ipi(cpu
);
638 static bool wake_up_full_nohz_cpu(int cpu
)
641 * We just need the target to call irq_exit() and re-evaluate
642 * the next tick. The nohz full kick at least implies that.
643 * If needed we can still optimize that later with an
646 if (tick_nohz_full_cpu(cpu
)) {
647 if (cpu
!= smp_processor_id() ||
648 tick_nohz_tick_stopped())
649 tick_nohz_full_kick_cpu(cpu
);
656 void wake_up_nohz_cpu(int cpu
)
658 if (!wake_up_full_nohz_cpu(cpu
))
659 wake_up_idle_cpu(cpu
);
662 static inline bool got_nohz_idle_kick(void)
664 int cpu
= smp_processor_id();
666 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
669 if (idle_cpu(cpu
) && !need_resched())
673 * We can't run Idle Load Balance on this CPU for this time so we
674 * cancel it and clear NOHZ_BALANCE_KICK
676 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
680 #else /* CONFIG_NO_HZ_COMMON */
682 static inline bool got_nohz_idle_kick(void)
687 #endif /* CONFIG_NO_HZ_COMMON */
689 #ifdef CONFIG_NO_HZ_FULL
690 bool sched_can_stop_tick(void)
693 * FIFO realtime policy runs the highest priority task. Other runnable
694 * tasks are of a lower priority. The scheduler tick does nothing.
696 if (current
->policy
== SCHED_FIFO
)
700 * Round-robin realtime tasks time slice with other tasks at the same
701 * realtime priority. Is this task the only one at this priority?
703 if (current
->policy
== SCHED_RR
) {
704 struct sched_rt_entity
*rt_se
= ¤t
->rt
;
706 return rt_se
->run_list
.prev
== rt_se
->run_list
.next
;
710 * More than one running task need preemption.
711 * nr_running update is assumed to be visible
712 * after IPI is sent from wakers.
714 if (this_rq()->nr_running
> 1)
719 #endif /* CONFIG_NO_HZ_FULL */
721 void sched_avg_update(struct rq
*rq
)
723 s64 period
= sched_avg_period();
725 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
727 * Inline assembly required to prevent the compiler
728 * optimising this loop into a divmod call.
729 * See __iter_div_u64_rem() for another example of this.
731 asm("" : "+rm" (rq
->age_stamp
));
732 rq
->age_stamp
+= period
;
737 #endif /* CONFIG_SMP */
739 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
740 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
742 * Iterate task_group tree rooted at *from, calling @down when first entering a
743 * node and @up when leaving it for the final time.
745 * Caller must hold rcu_lock or sufficient equivalent.
747 int walk_tg_tree_from(struct task_group
*from
,
748 tg_visitor down
, tg_visitor up
, void *data
)
750 struct task_group
*parent
, *child
;
756 ret
= (*down
)(parent
, data
);
759 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
766 ret
= (*up
)(parent
, data
);
767 if (ret
|| parent
== from
)
771 parent
= parent
->parent
;
778 int tg_nop(struct task_group
*tg
, void *data
)
784 static void set_load_weight(struct task_struct
*p
)
786 int prio
= p
->static_prio
- MAX_RT_PRIO
;
787 struct load_weight
*load
= &p
->se
.load
;
790 * SCHED_IDLE tasks get minimal weight:
792 if (p
->policy
== SCHED_IDLE
) {
793 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
794 load
->inv_weight
= WMULT_IDLEPRIO
;
798 load
->weight
= scale_load(prio_to_weight
[prio
]);
799 load
->inv_weight
= prio_to_wmult
[prio
];
802 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
805 sched_info_queued(rq
, p
);
806 p
->sched_class
->enqueue_task(rq
, p
, flags
);
809 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
812 sched_info_dequeued(rq
, p
);
813 p
->sched_class
->dequeue_task(rq
, p
, flags
);
816 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
818 if (task_contributes_to_load(p
))
819 rq
->nr_uninterruptible
--;
821 enqueue_task(rq
, p
, flags
);
824 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
826 if (task_contributes_to_load(p
))
827 rq
->nr_uninterruptible
++;
829 dequeue_task(rq
, p
, flags
);
832 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
835 * In theory, the compile should just see 0 here, and optimize out the call
836 * to sched_rt_avg_update. But I don't trust it...
838 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
839 s64 steal
= 0, irq_delta
= 0;
841 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
842 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
845 * Since irq_time is only updated on {soft,}irq_exit, we might run into
846 * this case when a previous update_rq_clock() happened inside a
849 * When this happens, we stop ->clock_task and only update the
850 * prev_irq_time stamp to account for the part that fit, so that a next
851 * update will consume the rest. This ensures ->clock_task is
854 * It does however cause some slight miss-attribution of {soft,}irq
855 * time, a more accurate solution would be to update the irq_time using
856 * the current rq->clock timestamp, except that would require using
859 if (irq_delta
> delta
)
862 rq
->prev_irq_time
+= irq_delta
;
865 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
866 if (static_key_false((¶virt_steal_rq_enabled
))) {
867 steal
= paravirt_steal_clock(cpu_of(rq
));
868 steal
-= rq
->prev_steal_time_rq
;
870 if (unlikely(steal
> delta
))
873 rq
->prev_steal_time_rq
+= steal
;
878 rq
->clock_task
+= delta
;
880 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
881 if ((irq_delta
+ steal
) && sched_feat(NONTASK_CAPACITY
))
882 sched_rt_avg_update(rq
, irq_delta
+ steal
);
886 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
888 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
889 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
893 * Make it appear like a SCHED_FIFO task, its something
894 * userspace knows about and won't get confused about.
896 * Also, it will make PI more or less work without too
897 * much confusion -- but then, stop work should not
898 * rely on PI working anyway.
900 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
902 stop
->sched_class
= &stop_sched_class
;
905 cpu_rq(cpu
)->stop
= stop
;
909 * Reset it back to a normal scheduling class so that
910 * it can die in pieces.
912 old_stop
->sched_class
= &rt_sched_class
;
917 * __normal_prio - return the priority that is based on the static prio
919 static inline int __normal_prio(struct task_struct
*p
)
921 return p
->static_prio
;
925 * Calculate the expected normal priority: i.e. priority
926 * without taking RT-inheritance into account. Might be
927 * boosted by interactivity modifiers. Changes upon fork,
928 * setprio syscalls, and whenever the interactivity
929 * estimator recalculates.
931 static inline int normal_prio(struct task_struct
*p
)
935 if (task_has_dl_policy(p
))
936 prio
= MAX_DL_PRIO
-1;
937 else if (task_has_rt_policy(p
))
938 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
940 prio
= __normal_prio(p
);
945 * Calculate the current priority, i.e. the priority
946 * taken into account by the scheduler. This value might
947 * be boosted by RT tasks, or might be boosted by
948 * interactivity modifiers. Will be RT if the task got
949 * RT-boosted. If not then it returns p->normal_prio.
951 static int effective_prio(struct task_struct
*p
)
953 p
->normal_prio
= normal_prio(p
);
955 * If we are RT tasks or we were boosted to RT priority,
956 * keep the priority unchanged. Otherwise, update priority
957 * to the normal priority:
959 if (!rt_prio(p
->prio
))
960 return p
->normal_prio
;
965 * task_curr - is this task currently executing on a CPU?
966 * @p: the task in question.
968 * Return: 1 if the task is currently executing. 0 otherwise.
970 inline int task_curr(const struct task_struct
*p
)
972 return cpu_curr(task_cpu(p
)) == p
;
976 * Can drop rq->lock because from sched_class::switched_from() methods drop it.
978 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
979 const struct sched_class
*prev_class
,
982 if (prev_class
!= p
->sched_class
) {
983 if (prev_class
->switched_from
)
984 prev_class
->switched_from(rq
, p
);
985 /* Possble rq->lock 'hole'. */
986 p
->sched_class
->switched_to(rq
, p
);
987 } else if (oldprio
!= p
->prio
|| dl_task(p
))
988 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
991 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
993 const struct sched_class
*class;
995 if (p
->sched_class
== rq
->curr
->sched_class
) {
996 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
998 for_each_class(class) {
999 if (class == rq
->curr
->sched_class
)
1001 if (class == p
->sched_class
) {
1009 * A queue event has occurred, and we're going to schedule. In
1010 * this case, we can save a useless back to back clock update.
1012 if (task_on_rq_queued(rq
->curr
) && test_tsk_need_resched(rq
->curr
))
1013 rq_clock_skip_update(rq
, true);
1017 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1019 #ifdef CONFIG_SCHED_DEBUG
1021 * We should never call set_task_cpu() on a blocked task,
1022 * ttwu() will sort out the placement.
1024 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
1027 #ifdef CONFIG_LOCKDEP
1029 * The caller should hold either p->pi_lock or rq->lock, when changing
1030 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1032 * sched_move_task() holds both and thus holding either pins the cgroup,
1035 * Furthermore, all task_rq users should acquire both locks, see
1038 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1039 lockdep_is_held(&task_rq(p
)->lock
)));
1043 trace_sched_migrate_task(p
, new_cpu
);
1045 if (task_cpu(p
) != new_cpu
) {
1046 if (p
->sched_class
->migrate_task_rq
)
1047 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1048 p
->se
.nr_migrations
++;
1049 perf_sw_event_sched(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, 0);
1052 __set_task_cpu(p
, new_cpu
);
1055 static void __migrate_swap_task(struct task_struct
*p
, int cpu
)
1057 if (task_on_rq_queued(p
)) {
1058 struct rq
*src_rq
, *dst_rq
;
1060 src_rq
= task_rq(p
);
1061 dst_rq
= cpu_rq(cpu
);
1063 deactivate_task(src_rq
, p
, 0);
1064 set_task_cpu(p
, cpu
);
1065 activate_task(dst_rq
, p
, 0);
1066 check_preempt_curr(dst_rq
, p
, 0);
1069 * Task isn't running anymore; make it appear like we migrated
1070 * it before it went to sleep. This means on wakeup we make the
1071 * previous cpu our targer instead of where it really is.
1077 struct migration_swap_arg
{
1078 struct task_struct
*src_task
, *dst_task
;
1079 int src_cpu
, dst_cpu
;
1082 static int migrate_swap_stop(void *data
)
1084 struct migration_swap_arg
*arg
= data
;
1085 struct rq
*src_rq
, *dst_rq
;
1088 src_rq
= cpu_rq(arg
->src_cpu
);
1089 dst_rq
= cpu_rq(arg
->dst_cpu
);
1091 double_raw_lock(&arg
->src_task
->pi_lock
,
1092 &arg
->dst_task
->pi_lock
);
1093 double_rq_lock(src_rq
, dst_rq
);
1094 if (task_cpu(arg
->dst_task
) != arg
->dst_cpu
)
1097 if (task_cpu(arg
->src_task
) != arg
->src_cpu
)
1100 if (!cpumask_test_cpu(arg
->dst_cpu
, tsk_cpus_allowed(arg
->src_task
)))
1103 if (!cpumask_test_cpu(arg
->src_cpu
, tsk_cpus_allowed(arg
->dst_task
)))
1106 __migrate_swap_task(arg
->src_task
, arg
->dst_cpu
);
1107 __migrate_swap_task(arg
->dst_task
, arg
->src_cpu
);
1112 double_rq_unlock(src_rq
, dst_rq
);
1113 raw_spin_unlock(&arg
->dst_task
->pi_lock
);
1114 raw_spin_unlock(&arg
->src_task
->pi_lock
);
1120 * Cross migrate two tasks
1122 int migrate_swap(struct task_struct
*cur
, struct task_struct
*p
)
1124 struct migration_swap_arg arg
;
1127 arg
= (struct migration_swap_arg
){
1129 .src_cpu
= task_cpu(cur
),
1131 .dst_cpu
= task_cpu(p
),
1134 if (arg
.src_cpu
== arg
.dst_cpu
)
1138 * These three tests are all lockless; this is OK since all of them
1139 * will be re-checked with proper locks held further down the line.
1141 if (!cpu_active(arg
.src_cpu
) || !cpu_active(arg
.dst_cpu
))
1144 if (!cpumask_test_cpu(arg
.dst_cpu
, tsk_cpus_allowed(arg
.src_task
)))
1147 if (!cpumask_test_cpu(arg
.src_cpu
, tsk_cpus_allowed(arg
.dst_task
)))
1150 trace_sched_swap_numa(cur
, arg
.src_cpu
, p
, arg
.dst_cpu
);
1151 ret
= stop_two_cpus(arg
.dst_cpu
, arg
.src_cpu
, migrate_swap_stop
, &arg
);
1157 struct migration_arg
{
1158 struct task_struct
*task
;
1162 static int migration_cpu_stop(void *data
);
1165 * wait_task_inactive - wait for a thread to unschedule.
1167 * If @match_state is nonzero, it's the @p->state value just checked and
1168 * not expected to change. If it changes, i.e. @p might have woken up,
1169 * then return zero. When we succeed in waiting for @p to be off its CPU,
1170 * we return a positive number (its total switch count). If a second call
1171 * a short while later returns the same number, the caller can be sure that
1172 * @p has remained unscheduled the whole time.
1174 * The caller must ensure that the task *will* unschedule sometime soon,
1175 * else this function might spin for a *long* time. This function can't
1176 * be called with interrupts off, or it may introduce deadlock with
1177 * smp_call_function() if an IPI is sent by the same process we are
1178 * waiting to become inactive.
1180 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1182 unsigned long flags
;
1183 int running
, queued
;
1189 * We do the initial early heuristics without holding
1190 * any task-queue locks at all. We'll only try to get
1191 * the runqueue lock when things look like they will
1197 * If the task is actively running on another CPU
1198 * still, just relax and busy-wait without holding
1201 * NOTE! Since we don't hold any locks, it's not
1202 * even sure that "rq" stays as the right runqueue!
1203 * But we don't care, since "task_running()" will
1204 * return false if the runqueue has changed and p
1205 * is actually now running somewhere else!
1207 while (task_running(rq
, p
)) {
1208 if (match_state
&& unlikely(p
->state
!= match_state
))
1214 * Ok, time to look more closely! We need the rq
1215 * lock now, to be *sure*. If we're wrong, we'll
1216 * just go back and repeat.
1218 rq
= task_rq_lock(p
, &flags
);
1219 trace_sched_wait_task(p
);
1220 running
= task_running(rq
, p
);
1221 queued
= task_on_rq_queued(p
);
1223 if (!match_state
|| p
->state
== match_state
)
1224 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1225 task_rq_unlock(rq
, p
, &flags
);
1228 * If it changed from the expected state, bail out now.
1230 if (unlikely(!ncsw
))
1234 * Was it really running after all now that we
1235 * checked with the proper locks actually held?
1237 * Oops. Go back and try again..
1239 if (unlikely(running
)) {
1245 * It's not enough that it's not actively running,
1246 * it must be off the runqueue _entirely_, and not
1249 * So if it was still runnable (but just not actively
1250 * running right now), it's preempted, and we should
1251 * yield - it could be a while.
1253 if (unlikely(queued
)) {
1254 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1256 set_current_state(TASK_UNINTERRUPTIBLE
);
1257 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1262 * Ahh, all good. It wasn't running, and it wasn't
1263 * runnable, which means that it will never become
1264 * running in the future either. We're all done!
1273 * kick_process - kick a running thread to enter/exit the kernel
1274 * @p: the to-be-kicked thread
1276 * Cause a process which is running on another CPU to enter
1277 * kernel-mode, without any delay. (to get signals handled.)
1279 * NOTE: this function doesn't have to take the runqueue lock,
1280 * because all it wants to ensure is that the remote task enters
1281 * the kernel. If the IPI races and the task has been migrated
1282 * to another CPU then no harm is done and the purpose has been
1285 void kick_process(struct task_struct
*p
)
1291 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1292 smp_send_reschedule(cpu
);
1295 EXPORT_SYMBOL_GPL(kick_process
);
1296 #endif /* CONFIG_SMP */
1300 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1302 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1304 int nid
= cpu_to_node(cpu
);
1305 const struct cpumask
*nodemask
= NULL
;
1306 enum { cpuset
, possible
, fail
} state
= cpuset
;
1310 * If the node that the cpu is on has been offlined, cpu_to_node()
1311 * will return -1. There is no cpu on the node, and we should
1312 * select the cpu on the other node.
1315 nodemask
= cpumask_of_node(nid
);
1317 /* Look for allowed, online CPU in same node. */
1318 for_each_cpu(dest_cpu
, nodemask
) {
1319 if (!cpu_online(dest_cpu
))
1321 if (!cpu_active(dest_cpu
))
1323 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1329 /* Any allowed, online CPU? */
1330 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1331 if (!cpu_online(dest_cpu
))
1333 if (!cpu_active(dest_cpu
))
1340 /* No more Mr. Nice Guy. */
1341 cpuset_cpus_allowed_fallback(p
);
1346 do_set_cpus_allowed(p
, cpu_possible_mask
);
1357 if (state
!= cpuset
) {
1359 * Don't tell them about moving exiting tasks or
1360 * kernel threads (both mm NULL), since they never
1363 if (p
->mm
&& printk_ratelimit()) {
1364 printk_deferred("process %d (%s) no longer affine to cpu%d\n",
1365 task_pid_nr(p
), p
->comm
, cpu
);
1373 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1376 int select_task_rq(struct task_struct
*p
, int cpu
, int sd_flags
, int wake_flags
)
1378 if (p
->nr_cpus_allowed
> 1)
1379 cpu
= p
->sched_class
->select_task_rq(p
, cpu
, sd_flags
, wake_flags
);
1382 * In order not to call set_task_cpu() on a blocking task we need
1383 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1386 * Since this is common to all placement strategies, this lives here.
1388 * [ this allows ->select_task() to simply return task_cpu(p) and
1389 * not worry about this generic constraint ]
1391 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1393 cpu
= select_fallback_rq(task_cpu(p
), p
);
1398 static void update_avg(u64
*avg
, u64 sample
)
1400 s64 diff
= sample
- *avg
;
1406 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1408 #ifdef CONFIG_SCHEDSTATS
1409 struct rq
*rq
= this_rq();
1412 int this_cpu
= smp_processor_id();
1414 if (cpu
== this_cpu
) {
1415 schedstat_inc(rq
, ttwu_local
);
1416 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1418 struct sched_domain
*sd
;
1420 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1422 for_each_domain(this_cpu
, sd
) {
1423 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1424 schedstat_inc(sd
, ttwu_wake_remote
);
1431 if (wake_flags
& WF_MIGRATED
)
1432 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1434 #endif /* CONFIG_SMP */
1436 schedstat_inc(rq
, ttwu_count
);
1437 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1439 if (wake_flags
& WF_SYNC
)
1440 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1442 #endif /* CONFIG_SCHEDSTATS */
1445 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1447 activate_task(rq
, p
, en_flags
);
1448 p
->on_rq
= TASK_ON_RQ_QUEUED
;
1450 /* if a worker is waking up, notify workqueue */
1451 if (p
->flags
& PF_WQ_WORKER
)
1452 wq_worker_waking_up(p
, cpu_of(rq
));
1456 * Mark the task runnable and perform wakeup-preemption.
1459 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1461 check_preempt_curr(rq
, p
, wake_flags
);
1462 trace_sched_wakeup(p
, true);
1464 p
->state
= TASK_RUNNING
;
1466 if (p
->sched_class
->task_woken
)
1467 p
->sched_class
->task_woken(rq
, p
);
1469 if (rq
->idle_stamp
) {
1470 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1471 u64 max
= 2*rq
->max_idle_balance_cost
;
1473 update_avg(&rq
->avg_idle
, delta
);
1475 if (rq
->avg_idle
> max
)
1484 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1487 if (p
->sched_contributes_to_load
)
1488 rq
->nr_uninterruptible
--;
1491 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1492 ttwu_do_wakeup(rq
, p
, wake_flags
);
1496 * Called in case the task @p isn't fully descheduled from its runqueue,
1497 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1498 * since all we need to do is flip p->state to TASK_RUNNING, since
1499 * the task is still ->on_rq.
1501 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1506 rq
= __task_rq_lock(p
);
1507 if (task_on_rq_queued(p
)) {
1508 /* check_preempt_curr() may use rq clock */
1509 update_rq_clock(rq
);
1510 ttwu_do_wakeup(rq
, p
, wake_flags
);
1513 __task_rq_unlock(rq
);
1519 void sched_ttwu_pending(void)
1521 struct rq
*rq
= this_rq();
1522 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1523 struct task_struct
*p
;
1524 unsigned long flags
;
1529 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1532 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1533 llist
= llist_next(llist
);
1534 ttwu_do_activate(rq
, p
, 0);
1537 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1540 void scheduler_ipi(void)
1543 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1544 * TIF_NEED_RESCHED remotely (for the first time) will also send
1547 preempt_fold_need_resched();
1549 if (llist_empty(&this_rq()->wake_list
) && !got_nohz_idle_kick())
1553 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1554 * traditionally all their work was done from the interrupt return
1555 * path. Now that we actually do some work, we need to make sure
1558 * Some archs already do call them, luckily irq_enter/exit nest
1561 * Arguably we should visit all archs and update all handlers,
1562 * however a fair share of IPIs are still resched only so this would
1563 * somewhat pessimize the simple resched case.
1566 sched_ttwu_pending();
1569 * Check if someone kicked us for doing the nohz idle load balance.
1571 if (unlikely(got_nohz_idle_kick())) {
1572 this_rq()->idle_balance
= 1;
1573 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1578 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1580 struct rq
*rq
= cpu_rq(cpu
);
1582 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
)) {
1583 if (!set_nr_if_polling(rq
->idle
))
1584 smp_send_reschedule(cpu
);
1586 trace_sched_wake_idle_without_ipi(cpu
);
1590 void wake_up_if_idle(int cpu
)
1592 struct rq
*rq
= cpu_rq(cpu
);
1593 unsigned long flags
;
1597 if (!is_idle_task(rcu_dereference(rq
->curr
)))
1600 if (set_nr_if_polling(rq
->idle
)) {
1601 trace_sched_wake_idle_without_ipi(cpu
);
1603 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1604 if (is_idle_task(rq
->curr
))
1605 smp_send_reschedule(cpu
);
1606 /* Else cpu is not in idle, do nothing here */
1607 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1614 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1616 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1618 #endif /* CONFIG_SMP */
1620 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1622 struct rq
*rq
= cpu_rq(cpu
);
1624 #if defined(CONFIG_SMP)
1625 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1626 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1627 ttwu_queue_remote(p
, cpu
);
1632 raw_spin_lock(&rq
->lock
);
1633 ttwu_do_activate(rq
, p
, 0);
1634 raw_spin_unlock(&rq
->lock
);
1638 * try_to_wake_up - wake up a thread
1639 * @p: the thread to be awakened
1640 * @state: the mask of task states that can be woken
1641 * @wake_flags: wake modifier flags (WF_*)
1643 * Put it on the run-queue if it's not already there. The "current"
1644 * thread is always on the run-queue (except when the actual
1645 * re-schedule is in progress), and as such you're allowed to do
1646 * the simpler "current->state = TASK_RUNNING" to mark yourself
1647 * runnable without the overhead of this.
1649 * Return: %true if @p was woken up, %false if it was already running.
1650 * or @state didn't match @p's state.
1653 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1655 unsigned long flags
;
1656 int cpu
, success
= 0;
1659 * If we are going to wake up a thread waiting for CONDITION we
1660 * need to ensure that CONDITION=1 done by the caller can not be
1661 * reordered with p->state check below. This pairs with mb() in
1662 * set_current_state() the waiting thread does.
1664 smp_mb__before_spinlock();
1665 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1666 if (!(p
->state
& state
))
1669 success
= 1; /* we're going to change ->state */
1672 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1677 * If the owning (remote) cpu is still in the middle of schedule() with
1678 * this task as prev, wait until its done referencing the task.
1683 * Pairs with the smp_wmb() in finish_lock_switch().
1687 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1688 p
->state
= TASK_WAKING
;
1690 if (p
->sched_class
->task_waking
)
1691 p
->sched_class
->task_waking(p
);
1693 cpu
= select_task_rq(p
, p
->wake_cpu
, SD_BALANCE_WAKE
, wake_flags
);
1694 if (task_cpu(p
) != cpu
) {
1695 wake_flags
|= WF_MIGRATED
;
1696 set_task_cpu(p
, cpu
);
1698 #endif /* CONFIG_SMP */
1702 ttwu_stat(p
, cpu
, wake_flags
);
1704 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1710 * try_to_wake_up_local - try to wake up a local task with rq lock held
1711 * @p: the thread to be awakened
1713 * Put @p on the run-queue if it's not already there. The caller must
1714 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1717 static void try_to_wake_up_local(struct task_struct
*p
)
1719 struct rq
*rq
= task_rq(p
);
1721 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1722 WARN_ON_ONCE(p
== current
))
1725 lockdep_assert_held(&rq
->lock
);
1727 if (!raw_spin_trylock(&p
->pi_lock
)) {
1728 raw_spin_unlock(&rq
->lock
);
1729 raw_spin_lock(&p
->pi_lock
);
1730 raw_spin_lock(&rq
->lock
);
1733 if (!(p
->state
& TASK_NORMAL
))
1736 if (!task_on_rq_queued(p
))
1737 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1739 ttwu_do_wakeup(rq
, p
, 0);
1740 ttwu_stat(p
, smp_processor_id(), 0);
1742 raw_spin_unlock(&p
->pi_lock
);
1746 * wake_up_process - Wake up a specific process
1747 * @p: The process to be woken up.
1749 * Attempt to wake up the nominated process and move it to the set of runnable
1752 * Return: 1 if the process was woken up, 0 if it was already running.
1754 * It may be assumed that this function implies a write memory barrier before
1755 * changing the task state if and only if any tasks are woken up.
1757 int wake_up_process(struct task_struct
*p
)
1759 WARN_ON(task_is_stopped_or_traced(p
));
1760 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1762 EXPORT_SYMBOL(wake_up_process
);
1764 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1766 return try_to_wake_up(p
, state
, 0);
1770 * This function clears the sched_dl_entity static params.
1772 void __dl_clear_params(struct task_struct
*p
)
1774 struct sched_dl_entity
*dl_se
= &p
->dl
;
1776 dl_se
->dl_runtime
= 0;
1777 dl_se
->dl_deadline
= 0;
1778 dl_se
->dl_period
= 0;
1782 dl_se
->dl_throttled
= 0;
1784 dl_se
->dl_yielded
= 0;
1788 * Perform scheduler related setup for a newly forked process p.
1789 * p is forked by current.
1791 * __sched_fork() is basic setup used by init_idle() too:
1793 static void __sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1798 p
->se
.exec_start
= 0;
1799 p
->se
.sum_exec_runtime
= 0;
1800 p
->se
.prev_sum_exec_runtime
= 0;
1801 p
->se
.nr_migrations
= 0;
1804 p
->se
.avg
.decay_count
= 0;
1806 INIT_LIST_HEAD(&p
->se
.group_node
);
1808 #ifdef CONFIG_SCHEDSTATS
1809 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1812 RB_CLEAR_NODE(&p
->dl
.rb_node
);
1813 init_dl_task_timer(&p
->dl
);
1814 __dl_clear_params(p
);
1816 INIT_LIST_HEAD(&p
->rt
.run_list
);
1818 #ifdef CONFIG_PREEMPT_NOTIFIERS
1819 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1822 #ifdef CONFIG_NUMA_BALANCING
1823 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1824 p
->mm
->numa_next_scan
= jiffies
+ msecs_to_jiffies(sysctl_numa_balancing_scan_delay
);
1825 p
->mm
->numa_scan_seq
= 0;
1828 if (clone_flags
& CLONE_VM
)
1829 p
->numa_preferred_nid
= current
->numa_preferred_nid
;
1831 p
->numa_preferred_nid
= -1;
1833 p
->node_stamp
= 0ULL;
1834 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1835 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1836 p
->numa_work
.next
= &p
->numa_work
;
1837 p
->numa_faults
= NULL
;
1838 p
->last_task_numa_placement
= 0;
1839 p
->last_sum_exec_runtime
= 0;
1841 p
->numa_group
= NULL
;
1842 #endif /* CONFIG_NUMA_BALANCING */
1845 #ifdef CONFIG_NUMA_BALANCING
1846 #ifdef CONFIG_SCHED_DEBUG
1847 void set_numabalancing_state(bool enabled
)
1850 sched_feat_set("NUMA");
1852 sched_feat_set("NO_NUMA");
1855 __read_mostly
bool numabalancing_enabled
;
1857 void set_numabalancing_state(bool enabled
)
1859 numabalancing_enabled
= enabled
;
1861 #endif /* CONFIG_SCHED_DEBUG */
1863 #ifdef CONFIG_PROC_SYSCTL
1864 int sysctl_numa_balancing(struct ctl_table
*table
, int write
,
1865 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1869 int state
= numabalancing_enabled
;
1871 if (write
&& !capable(CAP_SYS_ADMIN
))
1876 err
= proc_dointvec_minmax(&t
, write
, buffer
, lenp
, ppos
);
1880 set_numabalancing_state(state
);
1887 * fork()/clone()-time setup:
1889 int sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1891 unsigned long flags
;
1892 int cpu
= get_cpu();
1894 __sched_fork(clone_flags
, p
);
1896 * We mark the process as running here. This guarantees that
1897 * nobody will actually run it, and a signal or other external
1898 * event cannot wake it up and insert it on the runqueue either.
1900 p
->state
= TASK_RUNNING
;
1903 * Make sure we do not leak PI boosting priority to the child.
1905 p
->prio
= current
->normal_prio
;
1908 * Revert to default priority/policy on fork if requested.
1910 if (unlikely(p
->sched_reset_on_fork
)) {
1911 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
1912 p
->policy
= SCHED_NORMAL
;
1913 p
->static_prio
= NICE_TO_PRIO(0);
1915 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1916 p
->static_prio
= NICE_TO_PRIO(0);
1918 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1922 * We don't need the reset flag anymore after the fork. It has
1923 * fulfilled its duty:
1925 p
->sched_reset_on_fork
= 0;
1928 if (dl_prio(p
->prio
)) {
1931 } else if (rt_prio(p
->prio
)) {
1932 p
->sched_class
= &rt_sched_class
;
1934 p
->sched_class
= &fair_sched_class
;
1937 if (p
->sched_class
->task_fork
)
1938 p
->sched_class
->task_fork(p
);
1941 * The child is not yet in the pid-hash so no cgroup attach races,
1942 * and the cgroup is pinned to this child due to cgroup_fork()
1943 * is ran before sched_fork().
1945 * Silence PROVE_RCU.
1947 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1948 set_task_cpu(p
, cpu
);
1949 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1951 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1952 if (likely(sched_info_on()))
1953 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1955 #if defined(CONFIG_SMP)
1958 init_task_preempt_count(p
);
1960 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1961 RB_CLEAR_NODE(&p
->pushable_dl_tasks
);
1968 unsigned long to_ratio(u64 period
, u64 runtime
)
1970 if (runtime
== RUNTIME_INF
)
1974 * Doing this here saves a lot of checks in all
1975 * the calling paths, and returning zero seems
1976 * safe for them anyway.
1981 return div64_u64(runtime
<< 20, period
);
1985 inline struct dl_bw
*dl_bw_of(int i
)
1987 rcu_lockdep_assert(rcu_read_lock_sched_held(),
1988 "sched RCU must be held");
1989 return &cpu_rq(i
)->rd
->dl_bw
;
1992 static inline int dl_bw_cpus(int i
)
1994 struct root_domain
*rd
= cpu_rq(i
)->rd
;
1997 rcu_lockdep_assert(rcu_read_lock_sched_held(),
1998 "sched RCU must be held");
1999 for_each_cpu_and(i
, rd
->span
, cpu_active_mask
)
2005 inline struct dl_bw
*dl_bw_of(int i
)
2007 return &cpu_rq(i
)->dl
.dl_bw
;
2010 static inline int dl_bw_cpus(int i
)
2017 * We must be sure that accepting a new task (or allowing changing the
2018 * parameters of an existing one) is consistent with the bandwidth
2019 * constraints. If yes, this function also accordingly updates the currently
2020 * allocated bandwidth to reflect the new situation.
2022 * This function is called while holding p's rq->lock.
2024 * XXX we should delay bw change until the task's 0-lag point, see
2027 static int dl_overflow(struct task_struct
*p
, int policy
,
2028 const struct sched_attr
*attr
)
2031 struct dl_bw
*dl_b
= dl_bw_of(task_cpu(p
));
2032 u64 period
= attr
->sched_period
?: attr
->sched_deadline
;
2033 u64 runtime
= attr
->sched_runtime
;
2034 u64 new_bw
= dl_policy(policy
) ? to_ratio(period
, runtime
) : 0;
2037 if (new_bw
== p
->dl
.dl_bw
)
2041 * Either if a task, enters, leave, or stays -deadline but changes
2042 * its parameters, we may need to update accordingly the total
2043 * allocated bandwidth of the container.
2045 raw_spin_lock(&dl_b
->lock
);
2046 cpus
= dl_bw_cpus(task_cpu(p
));
2047 if (dl_policy(policy
) && !task_has_dl_policy(p
) &&
2048 !__dl_overflow(dl_b
, cpus
, 0, new_bw
)) {
2049 __dl_add(dl_b
, new_bw
);
2051 } else if (dl_policy(policy
) && task_has_dl_policy(p
) &&
2052 !__dl_overflow(dl_b
, cpus
, p
->dl
.dl_bw
, new_bw
)) {
2053 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2054 __dl_add(dl_b
, new_bw
);
2056 } else if (!dl_policy(policy
) && task_has_dl_policy(p
)) {
2057 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2060 raw_spin_unlock(&dl_b
->lock
);
2065 extern void init_dl_bw(struct dl_bw
*dl_b
);
2068 * wake_up_new_task - wake up a newly created task for the first time.
2070 * This function will do some initial scheduler statistics housekeeping
2071 * that must be done for every newly created context, then puts the task
2072 * on the runqueue and wakes it.
2074 void wake_up_new_task(struct task_struct
*p
)
2076 unsigned long flags
;
2079 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2082 * Fork balancing, do it here and not earlier because:
2083 * - cpus_allowed can change in the fork path
2084 * - any previously selected cpu might disappear through hotplug
2086 set_task_cpu(p
, select_task_rq(p
, task_cpu(p
), SD_BALANCE_FORK
, 0));
2089 /* Initialize new task's runnable average */
2090 init_task_runnable_average(p
);
2091 rq
= __task_rq_lock(p
);
2092 activate_task(rq
, p
, 0);
2093 p
->on_rq
= TASK_ON_RQ_QUEUED
;
2094 trace_sched_wakeup_new(p
, true);
2095 check_preempt_curr(rq
, p
, WF_FORK
);
2097 if (p
->sched_class
->task_woken
)
2098 p
->sched_class
->task_woken(rq
, p
);
2100 task_rq_unlock(rq
, p
, &flags
);
2103 #ifdef CONFIG_PREEMPT_NOTIFIERS
2106 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2107 * @notifier: notifier struct to register
2109 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2111 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2113 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2116 * preempt_notifier_unregister - no longer interested in preemption notifications
2117 * @notifier: notifier struct to unregister
2119 * This is safe to call from within a preemption notifier.
2121 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2123 hlist_del(¬ifier
->link
);
2125 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2127 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2129 struct preempt_notifier
*notifier
;
2131 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2132 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2136 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2137 struct task_struct
*next
)
2139 struct preempt_notifier
*notifier
;
2141 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2142 notifier
->ops
->sched_out(notifier
, next
);
2145 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2147 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2152 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2153 struct task_struct
*next
)
2157 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2160 * prepare_task_switch - prepare to switch tasks
2161 * @rq: the runqueue preparing to switch
2162 * @prev: the current task that is being switched out
2163 * @next: the task we are going to switch to.
2165 * This is called with the rq lock held and interrupts off. It must
2166 * be paired with a subsequent finish_task_switch after the context
2169 * prepare_task_switch sets up locking and calls architecture specific
2173 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2174 struct task_struct
*next
)
2176 trace_sched_switch(prev
, next
);
2177 sched_info_switch(rq
, prev
, next
);
2178 perf_event_task_sched_out(prev
, next
);
2179 fire_sched_out_preempt_notifiers(prev
, next
);
2180 prepare_lock_switch(rq
, next
);
2181 prepare_arch_switch(next
);
2185 * finish_task_switch - clean up after a task-switch
2186 * @prev: the thread we just switched away from.
2188 * finish_task_switch must be called after the context switch, paired
2189 * with a prepare_task_switch call before the context switch.
2190 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2191 * and do any other architecture-specific cleanup actions.
2193 * Note that we may have delayed dropping an mm in context_switch(). If
2194 * so, we finish that here outside of the runqueue lock. (Doing it
2195 * with the lock held can cause deadlocks; see schedule() for
2198 * The context switch have flipped the stack from under us and restored the
2199 * local variables which were saved when this task called schedule() in the
2200 * past. prev == current is still correct but we need to recalculate this_rq
2201 * because prev may have moved to another CPU.
2203 static struct rq
*finish_task_switch(struct task_struct
*prev
)
2204 __releases(rq
->lock
)
2206 struct rq
*rq
= this_rq();
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
);
2251 /* rq->lock is NOT held, but preemption is disabled */
2252 static inline void post_schedule(struct rq
*rq
)
2254 if (rq
->post_schedule
) {
2255 unsigned long flags
;
2257 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2258 if (rq
->curr
->sched_class
->post_schedule
)
2259 rq
->curr
->sched_class
->post_schedule(rq
);
2260 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2262 rq
->post_schedule
= 0;
2268 static inline void post_schedule(struct rq
*rq
)
2275 * schedule_tail - first thing a freshly forked thread must call.
2276 * @prev: the thread we just switched away from.
2278 asmlinkage __visible
void schedule_tail(struct task_struct
*prev
)
2279 __releases(rq
->lock
)
2283 /* finish_task_switch() drops rq->lock and enables preemtion */
2285 rq
= finish_task_switch(prev
);
2289 if (current
->set_child_tid
)
2290 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2294 * context_switch - switch to the new MM and the new thread's register state.
2296 static inline struct rq
*
2297 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2298 struct task_struct
*next
)
2300 struct mm_struct
*mm
, *oldmm
;
2302 prepare_task_switch(rq
, prev
, next
);
2305 oldmm
= prev
->active_mm
;
2307 * For paravirt, this is coupled with an exit in switch_to to
2308 * combine the page table reload and the switch backend into
2311 arch_start_context_switch(prev
);
2314 next
->active_mm
= oldmm
;
2315 atomic_inc(&oldmm
->mm_count
);
2316 enter_lazy_tlb(oldmm
, next
);
2318 switch_mm(oldmm
, mm
, next
);
2321 prev
->active_mm
= NULL
;
2322 rq
->prev_mm
= oldmm
;
2325 * Since the runqueue lock will be released by the next
2326 * task (which is an invalid locking op but in the case
2327 * of the scheduler it's an obvious special-case), so we
2328 * do an early lockdep release here:
2330 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2332 context_tracking_task_switch(prev
, next
);
2333 /* Here we just switch the register state and the stack. */
2334 switch_to(prev
, next
, prev
);
2337 return finish_task_switch(prev
);
2341 * nr_running and nr_context_switches:
2343 * externally visible scheduler statistics: current number of runnable
2344 * threads, total number of context switches performed since bootup.
2346 unsigned long nr_running(void)
2348 unsigned long i
, sum
= 0;
2350 for_each_online_cpu(i
)
2351 sum
+= cpu_rq(i
)->nr_running
;
2357 * Check if only the current task is running on the cpu.
2359 bool single_task_running(void)
2361 if (cpu_rq(smp_processor_id())->nr_running
== 1)
2366 EXPORT_SYMBOL(single_task_running
);
2368 unsigned long long nr_context_switches(void)
2371 unsigned long long sum
= 0;
2373 for_each_possible_cpu(i
)
2374 sum
+= cpu_rq(i
)->nr_switches
;
2379 unsigned long nr_iowait(void)
2381 unsigned long i
, sum
= 0;
2383 for_each_possible_cpu(i
)
2384 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2389 unsigned long nr_iowait_cpu(int cpu
)
2391 struct rq
*this = cpu_rq(cpu
);
2392 return atomic_read(&this->nr_iowait
);
2395 void get_iowait_load(unsigned long *nr_waiters
, unsigned long *load
)
2397 struct rq
*this = this_rq();
2398 *nr_waiters
= atomic_read(&this->nr_iowait
);
2399 *load
= this->cpu_load
[0];
2405 * sched_exec - execve() is a valuable balancing opportunity, because at
2406 * this point the task has the smallest effective memory and cache footprint.
2408 void sched_exec(void)
2410 struct task_struct
*p
= current
;
2411 unsigned long flags
;
2414 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2415 dest_cpu
= p
->sched_class
->select_task_rq(p
, task_cpu(p
), SD_BALANCE_EXEC
, 0);
2416 if (dest_cpu
== smp_processor_id())
2419 if (likely(cpu_active(dest_cpu
))) {
2420 struct migration_arg arg
= { p
, dest_cpu
};
2422 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2423 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2427 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2432 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2433 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2435 EXPORT_PER_CPU_SYMBOL(kstat
);
2436 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2439 * Return accounted runtime for the task.
2440 * In case the task is currently running, return the runtime plus current's
2441 * pending runtime that have not been accounted yet.
2443 unsigned long long task_sched_runtime(struct task_struct
*p
)
2445 unsigned long flags
;
2449 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2451 * 64-bit doesn't need locks to atomically read a 64bit value.
2452 * So we have a optimization chance when the task's delta_exec is 0.
2453 * Reading ->on_cpu is racy, but this is ok.
2455 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2456 * If we race with it entering cpu, unaccounted time is 0. This is
2457 * indistinguishable from the read occurring a few cycles earlier.
2458 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
2459 * been accounted, so we're correct here as well.
2461 if (!p
->on_cpu
|| !task_on_rq_queued(p
))
2462 return p
->se
.sum_exec_runtime
;
2465 rq
= task_rq_lock(p
, &flags
);
2467 * Must be ->curr _and_ ->on_rq. If dequeued, we would
2468 * project cycles that may never be accounted to this
2469 * thread, breaking clock_gettime().
2471 if (task_current(rq
, p
) && task_on_rq_queued(p
)) {
2472 update_rq_clock(rq
);
2473 p
->sched_class
->update_curr(rq
);
2475 ns
= p
->se
.sum_exec_runtime
;
2476 task_rq_unlock(rq
, p
, &flags
);
2482 * This function gets called by the timer code, with HZ frequency.
2483 * We call it with interrupts disabled.
2485 void scheduler_tick(void)
2487 int cpu
= smp_processor_id();
2488 struct rq
*rq
= cpu_rq(cpu
);
2489 struct task_struct
*curr
= rq
->curr
;
2493 raw_spin_lock(&rq
->lock
);
2494 update_rq_clock(rq
);
2495 curr
->sched_class
->task_tick(rq
, curr
, 0);
2496 update_cpu_load_active(rq
);
2497 raw_spin_unlock(&rq
->lock
);
2499 perf_event_task_tick();
2502 rq
->idle_balance
= idle_cpu(cpu
);
2503 trigger_load_balance(rq
);
2505 rq_last_tick_reset(rq
);
2508 #ifdef CONFIG_NO_HZ_FULL
2510 * scheduler_tick_max_deferment
2512 * Keep at least one tick per second when a single
2513 * active task is running because the scheduler doesn't
2514 * yet completely support full dynticks environment.
2516 * This makes sure that uptime, CFS vruntime, load
2517 * balancing, etc... continue to move forward, even
2518 * with a very low granularity.
2520 * Return: Maximum deferment in nanoseconds.
2522 u64
scheduler_tick_max_deferment(void)
2524 struct rq
*rq
= this_rq();
2525 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2527 next
= rq
->last_sched_tick
+ HZ
;
2529 if (time_before_eq(next
, now
))
2532 return jiffies_to_nsecs(next
- now
);
2536 notrace
unsigned long get_parent_ip(unsigned long addr
)
2538 if (in_lock_functions(addr
)) {
2539 addr
= CALLER_ADDR2
;
2540 if (in_lock_functions(addr
))
2541 addr
= CALLER_ADDR3
;
2546 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2547 defined(CONFIG_PREEMPT_TRACER))
2549 void preempt_count_add(int val
)
2551 #ifdef CONFIG_DEBUG_PREEMPT
2555 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2558 __preempt_count_add(val
);
2559 #ifdef CONFIG_DEBUG_PREEMPT
2561 * Spinlock count overflowing soon?
2563 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2566 if (preempt_count() == val
) {
2567 unsigned long ip
= get_parent_ip(CALLER_ADDR1
);
2568 #ifdef CONFIG_DEBUG_PREEMPT
2569 current
->preempt_disable_ip
= ip
;
2571 trace_preempt_off(CALLER_ADDR0
, ip
);
2574 EXPORT_SYMBOL(preempt_count_add
);
2575 NOKPROBE_SYMBOL(preempt_count_add
);
2577 void preempt_count_sub(int val
)
2579 #ifdef CONFIG_DEBUG_PREEMPT
2583 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2586 * Is the spinlock portion underflowing?
2588 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2589 !(preempt_count() & PREEMPT_MASK
)))
2593 if (preempt_count() == val
)
2594 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2595 __preempt_count_sub(val
);
2597 EXPORT_SYMBOL(preempt_count_sub
);
2598 NOKPROBE_SYMBOL(preempt_count_sub
);
2603 * Print scheduling while atomic bug:
2605 static noinline
void __schedule_bug(struct task_struct
*prev
)
2607 if (oops_in_progress
)
2610 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2611 prev
->comm
, prev
->pid
, preempt_count());
2613 debug_show_held_locks(prev
);
2615 if (irqs_disabled())
2616 print_irqtrace_events(prev
);
2617 #ifdef CONFIG_DEBUG_PREEMPT
2618 if (in_atomic_preempt_off()) {
2619 pr_err("Preemption disabled at:");
2620 print_ip_sym(current
->preempt_disable_ip
);
2625 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2629 * Various schedule()-time debugging checks and statistics:
2631 static inline void schedule_debug(struct task_struct
*prev
)
2633 #ifdef CONFIG_SCHED_STACK_END_CHECK
2634 BUG_ON(unlikely(task_stack_end_corrupted(prev
)));
2637 * Test if we are atomic. Since do_exit() needs to call into
2638 * schedule() atomically, we ignore that path. Otherwise whine
2639 * if we are scheduling when we should not.
2641 if (unlikely(in_atomic_preempt_off() && prev
->state
!= TASK_DEAD
))
2642 __schedule_bug(prev
);
2645 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2647 schedstat_inc(this_rq(), sched_count
);
2651 * Pick up the highest-prio task:
2653 static inline struct task_struct
*
2654 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
2656 const struct sched_class
*class = &fair_sched_class
;
2657 struct task_struct
*p
;
2660 * Optimization: we know that if all tasks are in
2661 * the fair class we can call that function directly:
2663 if (likely(prev
->sched_class
== class &&
2664 rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2665 p
= fair_sched_class
.pick_next_task(rq
, prev
);
2666 if (unlikely(p
== RETRY_TASK
))
2669 /* assumes fair_sched_class->next == idle_sched_class */
2671 p
= idle_sched_class
.pick_next_task(rq
, prev
);
2677 for_each_class(class) {
2678 p
= class->pick_next_task(rq
, prev
);
2680 if (unlikely(p
== RETRY_TASK
))
2686 BUG(); /* the idle class will always have a runnable task */
2690 * __schedule() is the main scheduler function.
2692 * The main means of driving the scheduler and thus entering this function are:
2694 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2696 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2697 * paths. For example, see arch/x86/entry_64.S.
2699 * To drive preemption between tasks, the scheduler sets the flag in timer
2700 * interrupt handler scheduler_tick().
2702 * 3. Wakeups don't really cause entry into schedule(). They add a
2703 * task to the run-queue and that's it.
2705 * Now, if the new task added to the run-queue preempts the current
2706 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2707 * called on the nearest possible occasion:
2709 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2711 * - in syscall or exception context, at the next outmost
2712 * preempt_enable(). (this might be as soon as the wake_up()'s
2715 * - in IRQ context, return from interrupt-handler to
2716 * preemptible context
2718 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2721 * - cond_resched() call
2722 * - explicit schedule() call
2723 * - return from syscall or exception to user-space
2724 * - return from interrupt-handler to user-space
2726 * WARNING: all callers must re-check need_resched() afterward and reschedule
2727 * accordingly in case an event triggered the need for rescheduling (such as
2728 * an interrupt waking up a task) while preemption was disabled in __schedule().
2730 static void __sched
__schedule(void)
2732 struct task_struct
*prev
, *next
;
2733 unsigned long *switch_count
;
2738 cpu
= smp_processor_id();
2740 rcu_note_context_switch();
2743 schedule_debug(prev
);
2745 if (sched_feat(HRTICK
))
2749 * Make sure that signal_pending_state()->signal_pending() below
2750 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2751 * done by the caller to avoid the race with signal_wake_up().
2753 smp_mb__before_spinlock();
2754 raw_spin_lock_irq(&rq
->lock
);
2756 rq
->clock_skip_update
<<= 1; /* promote REQ to ACT */
2758 switch_count
= &prev
->nivcsw
;
2759 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2760 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2761 prev
->state
= TASK_RUNNING
;
2763 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2767 * If a worker went to sleep, notify and ask workqueue
2768 * whether it wants to wake up a task to maintain
2771 if (prev
->flags
& PF_WQ_WORKER
) {
2772 struct task_struct
*to_wakeup
;
2774 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2776 try_to_wake_up_local(to_wakeup
);
2779 switch_count
= &prev
->nvcsw
;
2782 if (task_on_rq_queued(prev
))
2783 update_rq_clock(rq
);
2785 next
= pick_next_task(rq
, prev
);
2786 clear_tsk_need_resched(prev
);
2787 clear_preempt_need_resched();
2788 rq
->clock_skip_update
= 0;
2790 if (likely(prev
!= next
)) {
2795 rq
= context_switch(rq
, prev
, next
); /* unlocks the rq */
2798 raw_spin_unlock_irq(&rq
->lock
);
2802 sched_preempt_enable_no_resched();
2805 static inline void sched_submit_work(struct task_struct
*tsk
)
2807 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2810 * If we are going to sleep and we have plugged IO queued,
2811 * make sure to submit it to avoid deadlocks.
2813 if (blk_needs_flush_plug(tsk
))
2814 blk_schedule_flush_plug(tsk
);
2817 asmlinkage __visible
void __sched
schedule(void)
2819 struct task_struct
*tsk
= current
;
2821 sched_submit_work(tsk
);
2824 } while (need_resched());
2826 EXPORT_SYMBOL(schedule
);
2828 #ifdef CONFIG_CONTEXT_TRACKING
2829 asmlinkage __visible
void __sched
schedule_user(void)
2832 * If we come here after a random call to set_need_resched(),
2833 * or we have been woken up remotely but the IPI has not yet arrived,
2834 * we haven't yet exited the RCU idle mode. Do it here manually until
2835 * we find a better solution.
2837 * NB: There are buggy callers of this function. Ideally we
2838 * should warn if prev_state != IN_USER, but that will trigger
2839 * too frequently to make sense yet.
2841 enum ctx_state prev_state
= exception_enter();
2843 exception_exit(prev_state
);
2848 * schedule_preempt_disabled - called with preemption disabled
2850 * Returns with preemption disabled. Note: preempt_count must be 1
2852 void __sched
schedule_preempt_disabled(void)
2854 sched_preempt_enable_no_resched();
2859 static void __sched notrace
preempt_schedule_common(void)
2862 __preempt_count_add(PREEMPT_ACTIVE
);
2864 __preempt_count_sub(PREEMPT_ACTIVE
);
2867 * Check again in case we missed a preemption opportunity
2868 * between schedule and now.
2871 } while (need_resched());
2874 #ifdef CONFIG_PREEMPT
2876 * this is the entry point to schedule() from in-kernel preemption
2877 * off of preempt_enable. Kernel preemptions off return from interrupt
2878 * occur there and call schedule directly.
2880 asmlinkage __visible
void __sched notrace
preempt_schedule(void)
2883 * If there is a non-zero preempt_count or interrupts are disabled,
2884 * we do not want to preempt the current task. Just return..
2886 if (likely(!preemptible()))
2889 preempt_schedule_common();
2891 NOKPROBE_SYMBOL(preempt_schedule
);
2892 EXPORT_SYMBOL(preempt_schedule
);
2894 #ifdef CONFIG_CONTEXT_TRACKING
2896 * preempt_schedule_context - preempt_schedule called by tracing
2898 * The tracing infrastructure uses preempt_enable_notrace to prevent
2899 * recursion and tracing preempt enabling caused by the tracing
2900 * infrastructure itself. But as tracing can happen in areas coming
2901 * from userspace or just about to enter userspace, a preempt enable
2902 * can occur before user_exit() is called. This will cause the scheduler
2903 * to be called when the system is still in usermode.
2905 * To prevent this, the preempt_enable_notrace will use this function
2906 * instead of preempt_schedule() to exit user context if needed before
2907 * calling the scheduler.
2909 asmlinkage __visible
void __sched notrace
preempt_schedule_context(void)
2911 enum ctx_state prev_ctx
;
2913 if (likely(!preemptible()))
2917 __preempt_count_add(PREEMPT_ACTIVE
);
2919 * Needs preempt disabled in case user_exit() is traced
2920 * and the tracer calls preempt_enable_notrace() causing
2921 * an infinite recursion.
2923 prev_ctx
= exception_enter();
2925 exception_exit(prev_ctx
);
2927 __preempt_count_sub(PREEMPT_ACTIVE
);
2929 } while (need_resched());
2931 EXPORT_SYMBOL_GPL(preempt_schedule_context
);
2932 #endif /* CONFIG_CONTEXT_TRACKING */
2934 #endif /* CONFIG_PREEMPT */
2937 * this is the entry point to schedule() from kernel preemption
2938 * off of irq context.
2939 * Note, that this is called and return with irqs disabled. This will
2940 * protect us against recursive calling from irq.
2942 asmlinkage __visible
void __sched
preempt_schedule_irq(void)
2944 enum ctx_state prev_state
;
2946 /* Catch callers which need to be fixed */
2947 BUG_ON(preempt_count() || !irqs_disabled());
2949 prev_state
= exception_enter();
2952 __preempt_count_add(PREEMPT_ACTIVE
);
2955 local_irq_disable();
2956 __preempt_count_sub(PREEMPT_ACTIVE
);
2959 * Check again in case we missed a preemption opportunity
2960 * between schedule and now.
2963 } while (need_resched());
2965 exception_exit(prev_state
);
2968 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2971 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2973 EXPORT_SYMBOL(default_wake_function
);
2975 #ifdef CONFIG_RT_MUTEXES
2978 * rt_mutex_setprio - set the current priority of a task
2980 * @prio: prio value (kernel-internal form)
2982 * This function changes the 'effective' priority of a task. It does
2983 * not touch ->normal_prio like __setscheduler().
2985 * Used by the rt_mutex code to implement priority inheritance
2986 * logic. Call site only calls if the priority of the task changed.
2988 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
2990 int oldprio
, queued
, running
, enqueue_flag
= 0;
2992 const struct sched_class
*prev_class
;
2994 BUG_ON(prio
> MAX_PRIO
);
2996 rq
= __task_rq_lock(p
);
2999 * Idle task boosting is a nono in general. There is one
3000 * exception, when PREEMPT_RT and NOHZ is active:
3002 * The idle task calls get_next_timer_interrupt() and holds
3003 * the timer wheel base->lock on the CPU and another CPU wants
3004 * to access the timer (probably to cancel it). We can safely
3005 * ignore the boosting request, as the idle CPU runs this code
3006 * with interrupts disabled and will complete the lock
3007 * protected section without being interrupted. So there is no
3008 * real need to boost.
3010 if (unlikely(p
== rq
->idle
)) {
3011 WARN_ON(p
!= rq
->curr
);
3012 WARN_ON(p
->pi_blocked_on
);
3016 trace_sched_pi_setprio(p
, prio
);
3018 prev_class
= p
->sched_class
;
3019 queued
= task_on_rq_queued(p
);
3020 running
= task_current(rq
, p
);
3022 dequeue_task(rq
, p
, 0);
3024 put_prev_task(rq
, p
);
3027 * Boosting condition are:
3028 * 1. -rt task is running and holds mutex A
3029 * --> -dl task blocks on mutex A
3031 * 2. -dl task is running and holds mutex A
3032 * --> -dl task blocks on mutex A and could preempt the
3035 if (dl_prio(prio
)) {
3036 struct task_struct
*pi_task
= rt_mutex_get_top_task(p
);
3037 if (!dl_prio(p
->normal_prio
) ||
3038 (pi_task
&& dl_entity_preempt(&pi_task
->dl
, &p
->dl
))) {
3039 p
->dl
.dl_boosted
= 1;
3040 p
->dl
.dl_throttled
= 0;
3041 enqueue_flag
= ENQUEUE_REPLENISH
;
3043 p
->dl
.dl_boosted
= 0;
3044 p
->sched_class
= &dl_sched_class
;
3045 } else if (rt_prio(prio
)) {
3046 if (dl_prio(oldprio
))
3047 p
->dl
.dl_boosted
= 0;
3049 enqueue_flag
= ENQUEUE_HEAD
;
3050 p
->sched_class
= &rt_sched_class
;
3052 if (dl_prio(oldprio
))
3053 p
->dl
.dl_boosted
= 0;
3054 if (rt_prio(oldprio
))
3056 p
->sched_class
= &fair_sched_class
;
3062 p
->sched_class
->set_curr_task(rq
);
3064 enqueue_task(rq
, p
, enqueue_flag
);
3066 check_class_changed(rq
, p
, prev_class
, oldprio
);
3068 __task_rq_unlock(rq
);
3072 void set_user_nice(struct task_struct
*p
, long nice
)
3074 int old_prio
, delta
, queued
;
3075 unsigned long flags
;
3078 if (task_nice(p
) == nice
|| nice
< MIN_NICE
|| nice
> MAX_NICE
)
3081 * We have to be careful, if called from sys_setpriority(),
3082 * the task might be in the middle of scheduling on another CPU.
3084 rq
= task_rq_lock(p
, &flags
);
3086 * The RT priorities are set via sched_setscheduler(), but we still
3087 * allow the 'normal' nice value to be set - but as expected
3088 * it wont have any effect on scheduling until the task is
3089 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3091 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
3092 p
->static_prio
= NICE_TO_PRIO(nice
);
3095 queued
= task_on_rq_queued(p
);
3097 dequeue_task(rq
, p
, 0);
3099 p
->static_prio
= NICE_TO_PRIO(nice
);
3102 p
->prio
= effective_prio(p
);
3103 delta
= p
->prio
- old_prio
;
3106 enqueue_task(rq
, p
, 0);
3108 * If the task increased its priority or is running and
3109 * lowered its priority, then reschedule its CPU:
3111 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3115 task_rq_unlock(rq
, p
, &flags
);
3117 EXPORT_SYMBOL(set_user_nice
);
3120 * can_nice - check if a task can reduce its nice value
3124 int can_nice(const struct task_struct
*p
, const int nice
)
3126 /* convert nice value [19,-20] to rlimit style value [1,40] */
3127 int nice_rlim
= nice_to_rlimit(nice
);
3129 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3130 capable(CAP_SYS_NICE
));
3133 #ifdef __ARCH_WANT_SYS_NICE
3136 * sys_nice - change the priority of the current process.
3137 * @increment: priority increment
3139 * sys_setpriority is a more generic, but much slower function that
3140 * does similar things.
3142 SYSCALL_DEFINE1(nice
, int, increment
)
3147 * Setpriority might change our priority at the same moment.
3148 * We don't have to worry. Conceptually one call occurs first
3149 * and we have a single winner.
3151 increment
= clamp(increment
, -NICE_WIDTH
, NICE_WIDTH
);
3152 nice
= task_nice(current
) + increment
;
3154 nice
= clamp_val(nice
, MIN_NICE
, MAX_NICE
);
3155 if (increment
< 0 && !can_nice(current
, nice
))
3158 retval
= security_task_setnice(current
, nice
);
3162 set_user_nice(current
, nice
);
3169 * task_prio - return the priority value of a given task.
3170 * @p: the task in question.
3172 * Return: The priority value as seen by users in /proc.
3173 * RT tasks are offset by -200. Normal tasks are centered
3174 * around 0, value goes from -16 to +15.
3176 int task_prio(const struct task_struct
*p
)
3178 return p
->prio
- MAX_RT_PRIO
;
3182 * idle_cpu - is a given cpu idle currently?
3183 * @cpu: the processor in question.
3185 * Return: 1 if the CPU is currently idle. 0 otherwise.
3187 int idle_cpu(int cpu
)
3189 struct rq
*rq
= cpu_rq(cpu
);
3191 if (rq
->curr
!= rq
->idle
)
3198 if (!llist_empty(&rq
->wake_list
))
3206 * idle_task - return the idle task for a given cpu.
3207 * @cpu: the processor in question.
3209 * Return: The idle task for the cpu @cpu.
3211 struct task_struct
*idle_task(int cpu
)
3213 return cpu_rq(cpu
)->idle
;
3217 * find_process_by_pid - find a process with a matching PID value.
3218 * @pid: the pid in question.
3220 * The task of @pid, if found. %NULL otherwise.
3222 static struct task_struct
*find_process_by_pid(pid_t pid
)
3224 return pid
? find_task_by_vpid(pid
) : current
;
3228 * This function initializes the sched_dl_entity of a newly becoming
3229 * SCHED_DEADLINE task.
3231 * Only the static values are considered here, the actual runtime and the
3232 * absolute deadline will be properly calculated when the task is enqueued
3233 * for the first time with its new policy.
3236 __setparam_dl(struct task_struct
*p
, const struct sched_attr
*attr
)
3238 struct sched_dl_entity
*dl_se
= &p
->dl
;
3240 dl_se
->dl_runtime
= attr
->sched_runtime
;
3241 dl_se
->dl_deadline
= attr
->sched_deadline
;
3242 dl_se
->dl_period
= attr
->sched_period
?: dl_se
->dl_deadline
;
3243 dl_se
->flags
= attr
->sched_flags
;
3244 dl_se
->dl_bw
= to_ratio(dl_se
->dl_period
, dl_se
->dl_runtime
);
3247 * Changing the parameters of a task is 'tricky' and we're not doing
3248 * the correct thing -- also see task_dead_dl() and switched_from_dl().
3250 * What we SHOULD do is delay the bandwidth release until the 0-lag
3251 * point. This would include retaining the task_struct until that time
3252 * and change dl_overflow() to not immediately decrement the current
3255 * Instead we retain the current runtime/deadline and let the new
3256 * parameters take effect after the current reservation period lapses.
3257 * This is safe (albeit pessimistic) because the 0-lag point is always
3258 * before the current scheduling deadline.
3260 * We can still have temporary overloads because we do not delay the
3261 * change in bandwidth until that time; so admission control is
3262 * not on the safe side. It does however guarantee tasks will never
3263 * consume more than promised.
3268 * sched_setparam() passes in -1 for its policy, to let the functions
3269 * it calls know not to change it.
3271 #define SETPARAM_POLICY -1
3273 static void __setscheduler_params(struct task_struct
*p
,
3274 const struct sched_attr
*attr
)
3276 int policy
= attr
->sched_policy
;
3278 if (policy
== SETPARAM_POLICY
)
3283 if (dl_policy(policy
))
3284 __setparam_dl(p
, attr
);
3285 else if (fair_policy(policy
))
3286 p
->static_prio
= NICE_TO_PRIO(attr
->sched_nice
);
3289 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3290 * !rt_policy. Always setting this ensures that things like
3291 * getparam()/getattr() don't report silly values for !rt tasks.
3293 p
->rt_priority
= attr
->sched_priority
;
3294 p
->normal_prio
= normal_prio(p
);
3298 /* Actually do priority change: must hold pi & rq lock. */
3299 static void __setscheduler(struct rq
*rq
, struct task_struct
*p
,
3300 const struct sched_attr
*attr
)
3302 __setscheduler_params(p
, attr
);
3305 * If we get here, there was no pi waiters boosting the
3306 * task. It is safe to use the normal prio.
3308 p
->prio
= normal_prio(p
);
3310 if (dl_prio(p
->prio
))
3311 p
->sched_class
= &dl_sched_class
;
3312 else if (rt_prio(p
->prio
))
3313 p
->sched_class
= &rt_sched_class
;
3315 p
->sched_class
= &fair_sched_class
;
3319 __getparam_dl(struct task_struct
*p
, struct sched_attr
*attr
)
3321 struct sched_dl_entity
*dl_se
= &p
->dl
;
3323 attr
->sched_priority
= p
->rt_priority
;
3324 attr
->sched_runtime
= dl_se
->dl_runtime
;
3325 attr
->sched_deadline
= dl_se
->dl_deadline
;
3326 attr
->sched_period
= dl_se
->dl_period
;
3327 attr
->sched_flags
= dl_se
->flags
;
3331 * This function validates the new parameters of a -deadline task.
3332 * We ask for the deadline not being zero, and greater or equal
3333 * than the runtime, as well as the period of being zero or
3334 * greater than deadline. Furthermore, we have to be sure that
3335 * user parameters are above the internal resolution of 1us (we
3336 * check sched_runtime only since it is always the smaller one) and
3337 * below 2^63 ns (we have to check both sched_deadline and
3338 * sched_period, as the latter can be zero).
3341 __checkparam_dl(const struct sched_attr
*attr
)
3344 if (attr
->sched_deadline
== 0)
3348 * Since we truncate DL_SCALE bits, make sure we're at least
3351 if (attr
->sched_runtime
< (1ULL << DL_SCALE
))
3355 * Since we use the MSB for wrap-around and sign issues, make
3356 * sure it's not set (mind that period can be equal to zero).
3358 if (attr
->sched_deadline
& (1ULL << 63) ||
3359 attr
->sched_period
& (1ULL << 63))
3362 /* runtime <= deadline <= period (if period != 0) */
3363 if ((attr
->sched_period
!= 0 &&
3364 attr
->sched_period
< attr
->sched_deadline
) ||
3365 attr
->sched_deadline
< attr
->sched_runtime
)
3372 * check the target process has a UID that matches the current process's
3374 static bool check_same_owner(struct task_struct
*p
)
3376 const struct cred
*cred
= current_cred(), *pcred
;
3380 pcred
= __task_cred(p
);
3381 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3382 uid_eq(cred
->euid
, pcred
->uid
));
3387 static bool dl_param_changed(struct task_struct
*p
,
3388 const struct sched_attr
*attr
)
3390 struct sched_dl_entity
*dl_se
= &p
->dl
;
3392 if (dl_se
->dl_runtime
!= attr
->sched_runtime
||
3393 dl_se
->dl_deadline
!= attr
->sched_deadline
||
3394 dl_se
->dl_period
!= attr
->sched_period
||
3395 dl_se
->flags
!= attr
->sched_flags
)
3401 static int __sched_setscheduler(struct task_struct
*p
,
3402 const struct sched_attr
*attr
,
3405 int newprio
= dl_policy(attr
->sched_policy
) ? MAX_DL_PRIO
- 1 :
3406 MAX_RT_PRIO
- 1 - attr
->sched_priority
;
3407 int retval
, oldprio
, oldpolicy
= -1, queued
, running
;
3408 int policy
= attr
->sched_policy
;
3409 unsigned long flags
;
3410 const struct sched_class
*prev_class
;
3414 /* may grab non-irq protected spin_locks */
3415 BUG_ON(in_interrupt());
3417 /* double check policy once rq lock held */
3419 reset_on_fork
= p
->sched_reset_on_fork
;
3420 policy
= oldpolicy
= p
->policy
;
3422 reset_on_fork
= !!(attr
->sched_flags
& SCHED_FLAG_RESET_ON_FORK
);
3424 if (policy
!= SCHED_DEADLINE
&&
3425 policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3426 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3427 policy
!= SCHED_IDLE
)
3431 if (attr
->sched_flags
& ~(SCHED_FLAG_RESET_ON_FORK
))
3435 * Valid priorities for SCHED_FIFO and SCHED_RR are
3436 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3437 * SCHED_BATCH and SCHED_IDLE is 0.
3439 if ((p
->mm
&& attr
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3440 (!p
->mm
&& attr
->sched_priority
> MAX_RT_PRIO
-1))
3442 if ((dl_policy(policy
) && !__checkparam_dl(attr
)) ||
3443 (rt_policy(policy
) != (attr
->sched_priority
!= 0)))
3447 * Allow unprivileged RT tasks to decrease priority:
3449 if (user
&& !capable(CAP_SYS_NICE
)) {
3450 if (fair_policy(policy
)) {
3451 if (attr
->sched_nice
< task_nice(p
) &&
3452 !can_nice(p
, attr
->sched_nice
))
3456 if (rt_policy(policy
)) {
3457 unsigned long rlim_rtprio
=
3458 task_rlimit(p
, RLIMIT_RTPRIO
);
3460 /* can't set/change the rt policy */
3461 if (policy
!= p
->policy
&& !rlim_rtprio
)
3464 /* can't increase priority */
3465 if (attr
->sched_priority
> p
->rt_priority
&&
3466 attr
->sched_priority
> rlim_rtprio
)
3471 * Can't set/change SCHED_DEADLINE policy at all for now
3472 * (safest behavior); in the future we would like to allow
3473 * unprivileged DL tasks to increase their relative deadline
3474 * or reduce their runtime (both ways reducing utilization)
3476 if (dl_policy(policy
))
3480 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3481 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3483 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3484 if (!can_nice(p
, task_nice(p
)))
3488 /* can't change other user's priorities */
3489 if (!check_same_owner(p
))
3492 /* Normal users shall not reset the sched_reset_on_fork flag */
3493 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3498 retval
= security_task_setscheduler(p
);
3504 * make sure no PI-waiters arrive (or leave) while we are
3505 * changing the priority of the task:
3507 * To be able to change p->policy safely, the appropriate
3508 * runqueue lock must be held.
3510 rq
= task_rq_lock(p
, &flags
);
3513 * Changing the policy of the stop threads its a very bad idea
3515 if (p
== rq
->stop
) {
3516 task_rq_unlock(rq
, p
, &flags
);
3521 * If not changing anything there's no need to proceed further,
3522 * but store a possible modification of reset_on_fork.
3524 if (unlikely(policy
== p
->policy
)) {
3525 if (fair_policy(policy
) && attr
->sched_nice
!= task_nice(p
))
3527 if (rt_policy(policy
) && attr
->sched_priority
!= p
->rt_priority
)
3529 if (dl_policy(policy
) && dl_param_changed(p
, attr
))
3532 p
->sched_reset_on_fork
= reset_on_fork
;
3533 task_rq_unlock(rq
, p
, &flags
);
3539 #ifdef CONFIG_RT_GROUP_SCHED
3541 * Do not allow realtime tasks into groups that have no runtime
3544 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3545 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3546 !task_group_is_autogroup(task_group(p
))) {
3547 task_rq_unlock(rq
, p
, &flags
);
3552 if (dl_bandwidth_enabled() && dl_policy(policy
)) {
3553 cpumask_t
*span
= rq
->rd
->span
;
3556 * Don't allow tasks with an affinity mask smaller than
3557 * the entire root_domain to become SCHED_DEADLINE. We
3558 * will also fail if there's no bandwidth available.
3560 if (!cpumask_subset(span
, &p
->cpus_allowed
) ||
3561 rq
->rd
->dl_bw
.bw
== 0) {
3562 task_rq_unlock(rq
, p
, &flags
);
3569 /* recheck policy now with rq lock held */
3570 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3571 policy
= oldpolicy
= -1;
3572 task_rq_unlock(rq
, p
, &flags
);
3577 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3578 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3581 if ((dl_policy(policy
) || dl_task(p
)) && dl_overflow(p
, policy
, attr
)) {
3582 task_rq_unlock(rq
, p
, &flags
);
3586 p
->sched_reset_on_fork
= reset_on_fork
;
3590 * Special case for priority boosted tasks.
3592 * If the new priority is lower or equal (user space view)
3593 * than the current (boosted) priority, we just store the new
3594 * normal parameters and do not touch the scheduler class and
3595 * the runqueue. This will be done when the task deboost
3598 if (rt_mutex_check_prio(p
, newprio
)) {
3599 __setscheduler_params(p
, attr
);
3600 task_rq_unlock(rq
, p
, &flags
);
3604 queued
= task_on_rq_queued(p
);
3605 running
= task_current(rq
, p
);
3607 dequeue_task(rq
, p
, 0);
3609 put_prev_task(rq
, p
);
3611 prev_class
= p
->sched_class
;
3612 __setscheduler(rq
, p
, attr
);
3615 p
->sched_class
->set_curr_task(rq
);
3618 * We enqueue to tail when the priority of a task is
3619 * increased (user space view).
3621 enqueue_task(rq
, p
, oldprio
<= p
->prio
? ENQUEUE_HEAD
: 0);
3624 check_class_changed(rq
, p
, prev_class
, oldprio
);
3625 task_rq_unlock(rq
, p
, &flags
);
3627 rt_mutex_adjust_pi(p
);
3632 static int _sched_setscheduler(struct task_struct
*p
, int policy
,
3633 const struct sched_param
*param
, bool check
)
3635 struct sched_attr attr
= {
3636 .sched_policy
= policy
,
3637 .sched_priority
= param
->sched_priority
,
3638 .sched_nice
= PRIO_TO_NICE(p
->static_prio
),
3641 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
3642 if ((policy
!= SETPARAM_POLICY
) && (policy
& SCHED_RESET_ON_FORK
)) {
3643 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3644 policy
&= ~SCHED_RESET_ON_FORK
;
3645 attr
.sched_policy
= policy
;
3648 return __sched_setscheduler(p
, &attr
, check
);
3651 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3652 * @p: the task in question.
3653 * @policy: new policy.
3654 * @param: structure containing the new RT priority.
3656 * Return: 0 on success. An error code otherwise.
3658 * NOTE that the task may be already dead.
3660 int sched_setscheduler(struct task_struct
*p
, int policy
,
3661 const struct sched_param
*param
)
3663 return _sched_setscheduler(p
, policy
, param
, true);
3665 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3667 int sched_setattr(struct task_struct
*p
, const struct sched_attr
*attr
)
3669 return __sched_setscheduler(p
, attr
, true);
3671 EXPORT_SYMBOL_GPL(sched_setattr
);
3674 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3675 * @p: the task in question.
3676 * @policy: new policy.
3677 * @param: structure containing the new RT priority.
3679 * Just like sched_setscheduler, only don't bother checking if the
3680 * current context has permission. For example, this is needed in
3681 * stop_machine(): we create temporary high priority worker threads,
3682 * but our caller might not have that capability.
3684 * Return: 0 on success. An error code otherwise.
3686 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3687 const struct sched_param
*param
)
3689 return _sched_setscheduler(p
, policy
, param
, false);
3693 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3695 struct sched_param lparam
;
3696 struct task_struct
*p
;
3699 if (!param
|| pid
< 0)
3701 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3706 p
= find_process_by_pid(pid
);
3708 retval
= sched_setscheduler(p
, policy
, &lparam
);
3715 * Mimics kernel/events/core.c perf_copy_attr().
3717 static int sched_copy_attr(struct sched_attr __user
*uattr
,
3718 struct sched_attr
*attr
)
3723 if (!access_ok(VERIFY_WRITE
, uattr
, SCHED_ATTR_SIZE_VER0
))
3727 * zero the full structure, so that a short copy will be nice.
3729 memset(attr
, 0, sizeof(*attr
));
3731 ret
= get_user(size
, &uattr
->size
);
3735 if (size
> PAGE_SIZE
) /* silly large */
3738 if (!size
) /* abi compat */
3739 size
= SCHED_ATTR_SIZE_VER0
;
3741 if (size
< SCHED_ATTR_SIZE_VER0
)
3745 * If we're handed a bigger struct than we know of,
3746 * ensure all the unknown bits are 0 - i.e. new
3747 * user-space does not rely on any kernel feature
3748 * extensions we dont know about yet.
3750 if (size
> sizeof(*attr
)) {
3751 unsigned char __user
*addr
;
3752 unsigned char __user
*end
;
3755 addr
= (void __user
*)uattr
+ sizeof(*attr
);
3756 end
= (void __user
*)uattr
+ size
;
3758 for (; addr
< end
; addr
++) {
3759 ret
= get_user(val
, addr
);
3765 size
= sizeof(*attr
);
3768 ret
= copy_from_user(attr
, uattr
, size
);
3773 * XXX: do we want to be lenient like existing syscalls; or do we want
3774 * to be strict and return an error on out-of-bounds values?
3776 attr
->sched_nice
= clamp(attr
->sched_nice
, MIN_NICE
, MAX_NICE
);
3781 put_user(sizeof(*attr
), &uattr
->size
);
3786 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3787 * @pid: the pid in question.
3788 * @policy: new policy.
3789 * @param: structure containing the new RT priority.
3791 * Return: 0 on success. An error code otherwise.
3793 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3794 struct sched_param __user
*, param
)
3796 /* negative values for policy are not valid */
3800 return do_sched_setscheduler(pid
, policy
, param
);
3804 * sys_sched_setparam - set/change the RT priority of a thread
3805 * @pid: the pid in question.
3806 * @param: structure containing the new RT priority.
3808 * Return: 0 on success. An error code otherwise.
3810 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3812 return do_sched_setscheduler(pid
, SETPARAM_POLICY
, param
);
3816 * sys_sched_setattr - same as above, but with extended sched_attr
3817 * @pid: the pid in question.
3818 * @uattr: structure containing the extended parameters.
3819 * @flags: for future extension.
3821 SYSCALL_DEFINE3(sched_setattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3822 unsigned int, flags
)
3824 struct sched_attr attr
;
3825 struct task_struct
*p
;
3828 if (!uattr
|| pid
< 0 || flags
)
3831 retval
= sched_copy_attr(uattr
, &attr
);
3835 if ((int)attr
.sched_policy
< 0)
3840 p
= find_process_by_pid(pid
);
3842 retval
= sched_setattr(p
, &attr
);
3849 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3850 * @pid: the pid in question.
3852 * Return: On success, the policy of the thread. Otherwise, a negative error
3855 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3857 struct task_struct
*p
;
3865 p
= find_process_by_pid(pid
);
3867 retval
= security_task_getscheduler(p
);
3870 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3877 * sys_sched_getparam - get the RT priority of a thread
3878 * @pid: the pid in question.
3879 * @param: structure containing the RT priority.
3881 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3884 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3886 struct sched_param lp
= { .sched_priority
= 0 };
3887 struct task_struct
*p
;
3890 if (!param
|| pid
< 0)
3894 p
= find_process_by_pid(pid
);
3899 retval
= security_task_getscheduler(p
);
3903 if (task_has_rt_policy(p
))
3904 lp
.sched_priority
= p
->rt_priority
;
3908 * This one might sleep, we cannot do it with a spinlock held ...
3910 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3919 static int sched_read_attr(struct sched_attr __user
*uattr
,
3920 struct sched_attr
*attr
,
3925 if (!access_ok(VERIFY_WRITE
, uattr
, usize
))
3929 * If we're handed a smaller struct than we know of,
3930 * ensure all the unknown bits are 0 - i.e. old
3931 * user-space does not get uncomplete information.
3933 if (usize
< sizeof(*attr
)) {
3934 unsigned char *addr
;
3937 addr
= (void *)attr
+ usize
;
3938 end
= (void *)attr
+ sizeof(*attr
);
3940 for (; addr
< end
; addr
++) {
3948 ret
= copy_to_user(uattr
, attr
, attr
->size
);
3956 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
3957 * @pid: the pid in question.
3958 * @uattr: structure containing the extended parameters.
3959 * @size: sizeof(attr) for fwd/bwd comp.
3960 * @flags: for future extension.
3962 SYSCALL_DEFINE4(sched_getattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3963 unsigned int, size
, unsigned int, flags
)
3965 struct sched_attr attr
= {
3966 .size
= sizeof(struct sched_attr
),
3968 struct task_struct
*p
;
3971 if (!uattr
|| pid
< 0 || size
> PAGE_SIZE
||
3972 size
< SCHED_ATTR_SIZE_VER0
|| flags
)
3976 p
= find_process_by_pid(pid
);
3981 retval
= security_task_getscheduler(p
);
3985 attr
.sched_policy
= p
->policy
;
3986 if (p
->sched_reset_on_fork
)
3987 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3988 if (task_has_dl_policy(p
))
3989 __getparam_dl(p
, &attr
);
3990 else if (task_has_rt_policy(p
))
3991 attr
.sched_priority
= p
->rt_priority
;
3993 attr
.sched_nice
= task_nice(p
);
3997 retval
= sched_read_attr(uattr
, &attr
, size
);
4005 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4007 cpumask_var_t cpus_allowed
, new_mask
;
4008 struct task_struct
*p
;
4013 p
= find_process_by_pid(pid
);
4019 /* Prevent p going away */
4023 if (p
->flags
& PF_NO_SETAFFINITY
) {
4027 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4031 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4033 goto out_free_cpus_allowed
;
4036 if (!check_same_owner(p
)) {
4038 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
4040 goto out_free_new_mask
;
4045 retval
= security_task_setscheduler(p
);
4047 goto out_free_new_mask
;
4050 cpuset_cpus_allowed(p
, cpus_allowed
);
4051 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4054 * Since bandwidth control happens on root_domain basis,
4055 * if admission test is enabled, we only admit -deadline
4056 * tasks allowed to run on all the CPUs in the task's
4060 if (task_has_dl_policy(p
) && dl_bandwidth_enabled()) {
4062 if (!cpumask_subset(task_rq(p
)->rd
->span
, new_mask
)) {
4065 goto out_free_new_mask
;
4071 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4074 cpuset_cpus_allowed(p
, cpus_allowed
);
4075 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4077 * We must have raced with a concurrent cpuset
4078 * update. Just reset the cpus_allowed to the
4079 * cpuset's cpus_allowed
4081 cpumask_copy(new_mask
, cpus_allowed
);
4086 free_cpumask_var(new_mask
);
4087 out_free_cpus_allowed
:
4088 free_cpumask_var(cpus_allowed
);
4094 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4095 struct cpumask
*new_mask
)
4097 if (len
< cpumask_size())
4098 cpumask_clear(new_mask
);
4099 else if (len
> cpumask_size())
4100 len
= cpumask_size();
4102 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4106 * sys_sched_setaffinity - set the cpu affinity of a process
4107 * @pid: pid of the process
4108 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4109 * @user_mask_ptr: user-space pointer to the new cpu mask
4111 * Return: 0 on success. An error code otherwise.
4113 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4114 unsigned long __user
*, user_mask_ptr
)
4116 cpumask_var_t new_mask
;
4119 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4122 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4124 retval
= sched_setaffinity(pid
, new_mask
);
4125 free_cpumask_var(new_mask
);
4129 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4131 struct task_struct
*p
;
4132 unsigned long flags
;
4138 p
= find_process_by_pid(pid
);
4142 retval
= security_task_getscheduler(p
);
4146 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4147 cpumask_and(mask
, &p
->cpus_allowed
, cpu_active_mask
);
4148 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4157 * sys_sched_getaffinity - get the cpu affinity of a process
4158 * @pid: pid of the process
4159 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4160 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4162 * Return: 0 on success. An error code otherwise.
4164 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4165 unsigned long __user
*, user_mask_ptr
)
4170 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4172 if (len
& (sizeof(unsigned long)-1))
4175 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4178 ret
= sched_getaffinity(pid
, mask
);
4180 size_t retlen
= min_t(size_t, len
, cpumask_size());
4182 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4187 free_cpumask_var(mask
);
4193 * sys_sched_yield - yield the current processor to other threads.
4195 * This function yields the current CPU to other tasks. If there are no
4196 * other threads running on this CPU then this function will return.
4200 SYSCALL_DEFINE0(sched_yield
)
4202 struct rq
*rq
= this_rq_lock();
4204 schedstat_inc(rq
, yld_count
);
4205 current
->sched_class
->yield_task(rq
);
4208 * Since we are going to call schedule() anyway, there's
4209 * no need to preempt or enable interrupts:
4211 __release(rq
->lock
);
4212 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4213 do_raw_spin_unlock(&rq
->lock
);
4214 sched_preempt_enable_no_resched();
4221 int __sched
_cond_resched(void)
4223 if (should_resched()) {
4224 preempt_schedule_common();
4229 EXPORT_SYMBOL(_cond_resched
);
4232 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4233 * call schedule, and on return reacquire the lock.
4235 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4236 * operations here to prevent schedule() from being called twice (once via
4237 * spin_unlock(), once by hand).
4239 int __cond_resched_lock(spinlock_t
*lock
)
4241 int resched
= should_resched();
4244 lockdep_assert_held(lock
);
4246 if (spin_needbreak(lock
) || resched
) {
4249 preempt_schedule_common();
4257 EXPORT_SYMBOL(__cond_resched_lock
);
4259 int __sched
__cond_resched_softirq(void)
4261 BUG_ON(!in_softirq());
4263 if (should_resched()) {
4265 preempt_schedule_common();
4271 EXPORT_SYMBOL(__cond_resched_softirq
);
4274 * yield - yield the current processor to other threads.
4276 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4278 * The scheduler is at all times free to pick the calling task as the most
4279 * eligible task to run, if removing the yield() call from your code breaks
4280 * it, its already broken.
4282 * Typical broken usage is:
4287 * where one assumes that yield() will let 'the other' process run that will
4288 * make event true. If the current task is a SCHED_FIFO task that will never
4289 * happen. Never use yield() as a progress guarantee!!
4291 * If you want to use yield() to wait for something, use wait_event().
4292 * If you want to use yield() to be 'nice' for others, use cond_resched().
4293 * If you still want to use yield(), do not!
4295 void __sched
yield(void)
4297 set_current_state(TASK_RUNNING
);
4300 EXPORT_SYMBOL(yield
);
4303 * yield_to - yield the current processor to another thread in
4304 * your thread group, or accelerate that thread toward the
4305 * processor it's on.
4307 * @preempt: whether task preemption is allowed or not
4309 * It's the caller's job to ensure that the target task struct
4310 * can't go away on us before we can do any checks.
4313 * true (>0) if we indeed boosted the target task.
4314 * false (0) if we failed to boost the target.
4315 * -ESRCH if there's no task to yield to.
4317 int __sched
yield_to(struct task_struct
*p
, bool preempt
)
4319 struct task_struct
*curr
= current
;
4320 struct rq
*rq
, *p_rq
;
4321 unsigned long flags
;
4324 local_irq_save(flags
);
4330 * If we're the only runnable task on the rq and target rq also
4331 * has only one task, there's absolutely no point in yielding.
4333 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
4338 double_rq_lock(rq
, p_rq
);
4339 if (task_rq(p
) != p_rq
) {
4340 double_rq_unlock(rq
, p_rq
);
4344 if (!curr
->sched_class
->yield_to_task
)
4347 if (curr
->sched_class
!= p
->sched_class
)
4350 if (task_running(p_rq
, p
) || p
->state
)
4353 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4355 schedstat_inc(rq
, yld_count
);
4357 * Make p's CPU reschedule; pick_next_entity takes care of
4360 if (preempt
&& rq
!= p_rq
)
4365 double_rq_unlock(rq
, p_rq
);
4367 local_irq_restore(flags
);
4374 EXPORT_SYMBOL_GPL(yield_to
);
4377 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4378 * that process accounting knows that this is a task in IO wait state.
4380 long __sched
io_schedule_timeout(long timeout
)
4382 int old_iowait
= current
->in_iowait
;
4386 current
->in_iowait
= 1;
4388 blk_schedule_flush_plug(current
);
4390 blk_flush_plug(current
);
4392 delayacct_blkio_start();
4394 atomic_inc(&rq
->nr_iowait
);
4395 ret
= schedule_timeout(timeout
);
4396 current
->in_iowait
= old_iowait
;
4397 atomic_dec(&rq
->nr_iowait
);
4398 delayacct_blkio_end();
4402 EXPORT_SYMBOL(io_schedule_timeout
);
4405 * sys_sched_get_priority_max - return maximum RT priority.
4406 * @policy: scheduling class.
4408 * Return: On success, this syscall returns the maximum
4409 * rt_priority that can be used by a given scheduling class.
4410 * On failure, a negative error code is returned.
4412 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4419 ret
= MAX_USER_RT_PRIO
-1;
4421 case SCHED_DEADLINE
:
4432 * sys_sched_get_priority_min - return minimum RT priority.
4433 * @policy: scheduling class.
4435 * Return: On success, this syscall returns the minimum
4436 * rt_priority that can be used by a given scheduling class.
4437 * On failure, a negative error code is returned.
4439 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4448 case SCHED_DEADLINE
:
4458 * sys_sched_rr_get_interval - return the default timeslice of a process.
4459 * @pid: pid of the process.
4460 * @interval: userspace pointer to the timeslice value.
4462 * this syscall writes the default timeslice value of a given process
4463 * into the user-space timespec buffer. A value of '0' means infinity.
4465 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4468 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4469 struct timespec __user
*, interval
)
4471 struct task_struct
*p
;
4472 unsigned int time_slice
;
4473 unsigned long flags
;
4483 p
= find_process_by_pid(pid
);
4487 retval
= security_task_getscheduler(p
);
4491 rq
= task_rq_lock(p
, &flags
);
4493 if (p
->sched_class
->get_rr_interval
)
4494 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4495 task_rq_unlock(rq
, p
, &flags
);
4498 jiffies_to_timespec(time_slice
, &t
);
4499 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4507 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4509 void sched_show_task(struct task_struct
*p
)
4511 unsigned long free
= 0;
4513 unsigned long state
= p
->state
;
4516 state
= __ffs(state
) + 1;
4517 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4518 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4519 #if BITS_PER_LONG == 32
4520 if (state
== TASK_RUNNING
)
4521 printk(KERN_CONT
" running ");
4523 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4525 if (state
== TASK_RUNNING
)
4526 printk(KERN_CONT
" running task ");
4528 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4530 #ifdef CONFIG_DEBUG_STACK_USAGE
4531 free
= stack_not_used(p
);
4536 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4538 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4539 task_pid_nr(p
), ppid
,
4540 (unsigned long)task_thread_info(p
)->flags
);
4542 print_worker_info(KERN_INFO
, p
);
4543 show_stack(p
, NULL
);
4546 void show_state_filter(unsigned long state_filter
)
4548 struct task_struct
*g
, *p
;
4550 #if BITS_PER_LONG == 32
4552 " task PC stack pid father\n");
4555 " task PC stack pid father\n");
4558 for_each_process_thread(g
, p
) {
4560 * reset the NMI-timeout, listing all files on a slow
4561 * console might take a lot of time:
4563 touch_nmi_watchdog();
4564 if (!state_filter
|| (p
->state
& state_filter
))
4568 touch_all_softlockup_watchdogs();
4570 #ifdef CONFIG_SCHED_DEBUG
4571 sysrq_sched_debug_show();
4575 * Only show locks if all tasks are dumped:
4578 debug_show_all_locks();
4581 void init_idle_bootup_task(struct task_struct
*idle
)
4583 idle
->sched_class
= &idle_sched_class
;
4587 * init_idle - set up an idle thread for a given CPU
4588 * @idle: task in question
4589 * @cpu: cpu the idle task belongs to
4591 * NOTE: this function does not set the idle thread's NEED_RESCHED
4592 * flag, to make booting more robust.
4594 void init_idle(struct task_struct
*idle
, int cpu
)
4596 struct rq
*rq
= cpu_rq(cpu
);
4597 unsigned long flags
;
4599 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4601 __sched_fork(0, idle
);
4602 idle
->state
= TASK_RUNNING
;
4603 idle
->se
.exec_start
= sched_clock();
4605 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4607 * We're having a chicken and egg problem, even though we are
4608 * holding rq->lock, the cpu isn't yet set to this cpu so the
4609 * lockdep check in task_group() will fail.
4611 * Similar case to sched_fork(). / Alternatively we could
4612 * use task_rq_lock() here and obtain the other rq->lock.
4617 __set_task_cpu(idle
, cpu
);
4620 rq
->curr
= rq
->idle
= idle
;
4621 idle
->on_rq
= TASK_ON_RQ_QUEUED
;
4622 #if defined(CONFIG_SMP)
4625 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4627 /* Set the preempt count _outside_ the spinlocks! */
4628 init_idle_preempt_count(idle
, cpu
);
4631 * The idle tasks have their own, simple scheduling class:
4633 idle
->sched_class
= &idle_sched_class
;
4634 ftrace_graph_init_idle_task(idle
, cpu
);
4635 vtime_init_idle(idle
, cpu
);
4636 #if defined(CONFIG_SMP)
4637 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4641 int cpuset_cpumask_can_shrink(const struct cpumask
*cur
,
4642 const struct cpumask
*trial
)
4644 int ret
= 1, trial_cpus
;
4645 struct dl_bw
*cur_dl_b
;
4646 unsigned long flags
;
4648 if (!cpumask_weight(cur
))
4651 rcu_read_lock_sched();
4652 cur_dl_b
= dl_bw_of(cpumask_any(cur
));
4653 trial_cpus
= cpumask_weight(trial
);
4655 raw_spin_lock_irqsave(&cur_dl_b
->lock
, flags
);
4656 if (cur_dl_b
->bw
!= -1 &&
4657 cur_dl_b
->bw
* trial_cpus
< cur_dl_b
->total_bw
)
4659 raw_spin_unlock_irqrestore(&cur_dl_b
->lock
, flags
);
4660 rcu_read_unlock_sched();
4665 int task_can_attach(struct task_struct
*p
,
4666 const struct cpumask
*cs_cpus_allowed
)
4671 * Kthreads which disallow setaffinity shouldn't be moved
4672 * to a new cpuset; we don't want to change their cpu
4673 * affinity and isolating such threads by their set of
4674 * allowed nodes is unnecessary. Thus, cpusets are not
4675 * applicable for such threads. This prevents checking for
4676 * success of set_cpus_allowed_ptr() on all attached tasks
4677 * before cpus_allowed may be changed.
4679 if (p
->flags
& PF_NO_SETAFFINITY
) {
4685 if (dl_task(p
) && !cpumask_intersects(task_rq(p
)->rd
->span
,
4687 unsigned int dest_cpu
= cpumask_any_and(cpu_active_mask
,
4692 unsigned long flags
;
4694 rcu_read_lock_sched();
4695 dl_b
= dl_bw_of(dest_cpu
);
4696 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
4697 cpus
= dl_bw_cpus(dest_cpu
);
4698 overflow
= __dl_overflow(dl_b
, cpus
, 0, p
->dl
.dl_bw
);
4703 * We reserve space for this task in the destination
4704 * root_domain, as we can't fail after this point.
4705 * We will free resources in the source root_domain
4706 * later on (see set_cpus_allowed_dl()).
4708 __dl_add(dl_b
, p
->dl
.dl_bw
);
4710 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
4711 rcu_read_unlock_sched();
4721 * move_queued_task - move a queued task to new rq.
4723 * Returns (locked) new rq. Old rq's lock is released.
4725 static struct rq
*move_queued_task(struct task_struct
*p
, int new_cpu
)
4727 struct rq
*rq
= task_rq(p
);
4729 lockdep_assert_held(&rq
->lock
);
4731 dequeue_task(rq
, p
, 0);
4732 p
->on_rq
= TASK_ON_RQ_MIGRATING
;
4733 set_task_cpu(p
, new_cpu
);
4734 raw_spin_unlock(&rq
->lock
);
4736 rq
= cpu_rq(new_cpu
);
4738 raw_spin_lock(&rq
->lock
);
4739 BUG_ON(task_cpu(p
) != new_cpu
);
4740 p
->on_rq
= TASK_ON_RQ_QUEUED
;
4741 enqueue_task(rq
, p
, 0);
4742 check_preempt_curr(rq
, p
, 0);
4747 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4749 if (p
->sched_class
->set_cpus_allowed
)
4750 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4752 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4753 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4757 * This is how migration works:
4759 * 1) we invoke migration_cpu_stop() on the target CPU using
4761 * 2) stopper starts to run (implicitly forcing the migrated thread
4763 * 3) it checks whether the migrated task is still in the wrong runqueue.
4764 * 4) if it's in the wrong runqueue then the migration thread removes
4765 * it and puts it into the right queue.
4766 * 5) stopper completes and stop_one_cpu() returns and the migration
4771 * Change a given task's CPU affinity. Migrate the thread to a
4772 * proper CPU and schedule it away if the CPU it's executing on
4773 * is removed from the allowed bitmask.
4775 * NOTE: the caller must have a valid reference to the task, the
4776 * task must not exit() & deallocate itself prematurely. The
4777 * call is not atomic; no spinlocks may be held.
4779 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4781 unsigned long flags
;
4783 unsigned int dest_cpu
;
4786 rq
= task_rq_lock(p
, &flags
);
4788 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4791 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4796 do_set_cpus_allowed(p
, new_mask
);
4798 /* Can the task run on the task's current CPU? If so, we're done */
4799 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4802 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4803 if (task_running(rq
, p
) || p
->state
== TASK_WAKING
) {
4804 struct migration_arg arg
= { p
, dest_cpu
};
4805 /* Need help from migration thread: drop lock and wait. */
4806 task_rq_unlock(rq
, p
, &flags
);
4807 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4808 tlb_migrate_finish(p
->mm
);
4810 } else if (task_on_rq_queued(p
))
4811 rq
= move_queued_task(p
, dest_cpu
);
4813 task_rq_unlock(rq
, p
, &flags
);
4817 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4820 * Move (not current) task off this cpu, onto dest cpu. We're doing
4821 * this because either it can't run here any more (set_cpus_allowed()
4822 * away from this CPU, or CPU going down), or because we're
4823 * attempting to rebalance this task on exec (sched_exec).
4825 * So we race with normal scheduler movements, but that's OK, as long
4826 * as the task is no longer on this CPU.
4828 * Returns non-zero if task was successfully migrated.
4830 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4835 if (unlikely(!cpu_active(dest_cpu
)))
4838 rq
= cpu_rq(src_cpu
);
4840 raw_spin_lock(&p
->pi_lock
);
4841 raw_spin_lock(&rq
->lock
);
4842 /* Already moved. */
4843 if (task_cpu(p
) != src_cpu
)
4846 /* Affinity changed (again). */
4847 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4851 * If we're not on a rq, the next wake-up will ensure we're
4854 if (task_on_rq_queued(p
))
4855 rq
= move_queued_task(p
, dest_cpu
);
4859 raw_spin_unlock(&rq
->lock
);
4860 raw_spin_unlock(&p
->pi_lock
);
4864 #ifdef CONFIG_NUMA_BALANCING
4865 /* Migrate current task p to target_cpu */
4866 int migrate_task_to(struct task_struct
*p
, int target_cpu
)
4868 struct migration_arg arg
= { p
, target_cpu
};
4869 int curr_cpu
= task_cpu(p
);
4871 if (curr_cpu
== target_cpu
)
4874 if (!cpumask_test_cpu(target_cpu
, tsk_cpus_allowed(p
)))
4877 /* TODO: This is not properly updating schedstats */
4879 trace_sched_move_numa(p
, curr_cpu
, target_cpu
);
4880 return stop_one_cpu(curr_cpu
, migration_cpu_stop
, &arg
);
4884 * Requeue a task on a given node and accurately track the number of NUMA
4885 * tasks on the runqueues
4887 void sched_setnuma(struct task_struct
*p
, int nid
)
4890 unsigned long flags
;
4891 bool queued
, running
;
4893 rq
= task_rq_lock(p
, &flags
);
4894 queued
= task_on_rq_queued(p
);
4895 running
= task_current(rq
, p
);
4898 dequeue_task(rq
, p
, 0);
4900 put_prev_task(rq
, p
);
4902 p
->numa_preferred_nid
= nid
;
4905 p
->sched_class
->set_curr_task(rq
);
4907 enqueue_task(rq
, p
, 0);
4908 task_rq_unlock(rq
, p
, &flags
);
4913 * migration_cpu_stop - this will be executed by a highprio stopper thread
4914 * and performs thread migration by bumping thread off CPU then
4915 * 'pushing' onto another runqueue.
4917 static int migration_cpu_stop(void *data
)
4919 struct migration_arg
*arg
= data
;
4922 * The original target cpu might have gone down and we might
4923 * be on another cpu but it doesn't matter.
4925 local_irq_disable();
4927 * We need to explicitly wake pending tasks before running
4928 * __migrate_task() such that we will not miss enforcing cpus_allowed
4929 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
4931 sched_ttwu_pending();
4932 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4937 #ifdef CONFIG_HOTPLUG_CPU
4940 * Ensures that the idle task is using init_mm right before its cpu goes
4943 void idle_task_exit(void)
4945 struct mm_struct
*mm
= current
->active_mm
;
4947 BUG_ON(cpu_online(smp_processor_id()));
4949 if (mm
!= &init_mm
) {
4950 switch_mm(mm
, &init_mm
, current
);
4951 finish_arch_post_lock_switch();
4957 * Since this CPU is going 'away' for a while, fold any nr_active delta
4958 * we might have. Assumes we're called after migrate_tasks() so that the
4959 * nr_active count is stable.
4961 * Also see the comment "Global load-average calculations".
4963 static void calc_load_migrate(struct rq
*rq
)
4965 long delta
= calc_load_fold_active(rq
);
4967 atomic_long_add(delta
, &calc_load_tasks
);
4970 static void put_prev_task_fake(struct rq
*rq
, struct task_struct
*prev
)
4974 static const struct sched_class fake_sched_class
= {
4975 .put_prev_task
= put_prev_task_fake
,
4978 static struct task_struct fake_task
= {
4980 * Avoid pull_{rt,dl}_task()
4982 .prio
= MAX_PRIO
+ 1,
4983 .sched_class
= &fake_sched_class
,
4987 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4988 * try_to_wake_up()->select_task_rq().
4990 * Called with rq->lock held even though we'er in stop_machine() and
4991 * there's no concurrency possible, we hold the required locks anyway
4992 * because of lock validation efforts.
4994 static void migrate_tasks(unsigned int dead_cpu
)
4996 struct rq
*rq
= cpu_rq(dead_cpu
);
4997 struct task_struct
*next
, *stop
= rq
->stop
;
5001 * Fudge the rq selection such that the below task selection loop
5002 * doesn't get stuck on the currently eligible stop task.
5004 * We're currently inside stop_machine() and the rq is either stuck
5005 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5006 * either way we should never end up calling schedule() until we're
5012 * put_prev_task() and pick_next_task() sched
5013 * class method both need to have an up-to-date
5014 * value of rq->clock[_task]
5016 update_rq_clock(rq
);
5020 * There's this thread running, bail when that's the only
5023 if (rq
->nr_running
== 1)
5026 next
= pick_next_task(rq
, &fake_task
);
5028 next
->sched_class
->put_prev_task(rq
, next
);
5030 /* Find suitable destination for @next, with force if needed. */
5031 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
5032 raw_spin_unlock(&rq
->lock
);
5034 __migrate_task(next
, dead_cpu
, dest_cpu
);
5036 raw_spin_lock(&rq
->lock
);
5042 #endif /* CONFIG_HOTPLUG_CPU */
5044 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5046 static struct ctl_table sd_ctl_dir
[] = {
5048 .procname
= "sched_domain",
5054 static struct ctl_table sd_ctl_root
[] = {
5056 .procname
= "kernel",
5058 .child
= sd_ctl_dir
,
5063 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5065 struct ctl_table
*entry
=
5066 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5071 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5073 struct ctl_table
*entry
;
5076 * In the intermediate directories, both the child directory and
5077 * procname are dynamically allocated and could fail but the mode
5078 * will always be set. In the lowest directory the names are
5079 * static strings and all have proc handlers.
5081 for (entry
= *tablep
; entry
->mode
; entry
++) {
5083 sd_free_ctl_entry(&entry
->child
);
5084 if (entry
->proc_handler
== NULL
)
5085 kfree(entry
->procname
);
5092 static int min_load_idx
= 0;
5093 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
5096 set_table_entry(struct ctl_table
*entry
,
5097 const char *procname
, void *data
, int maxlen
,
5098 umode_t mode
, proc_handler
*proc_handler
,
5101 entry
->procname
= procname
;
5103 entry
->maxlen
= maxlen
;
5105 entry
->proc_handler
= proc_handler
;
5108 entry
->extra1
= &min_load_idx
;
5109 entry
->extra2
= &max_load_idx
;
5113 static struct ctl_table
*
5114 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5116 struct ctl_table
*table
= sd_alloc_ctl_entry(14);
5121 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5122 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5123 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5124 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5125 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5126 sizeof(int), 0644, proc_dointvec_minmax
, true);
5127 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5128 sizeof(int), 0644, proc_dointvec_minmax
, true);
5129 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5130 sizeof(int), 0644, proc_dointvec_minmax
, true);
5131 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5132 sizeof(int), 0644, proc_dointvec_minmax
, true);
5133 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5134 sizeof(int), 0644, proc_dointvec_minmax
, true);
5135 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5136 sizeof(int), 0644, proc_dointvec_minmax
, false);
5137 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5138 sizeof(int), 0644, proc_dointvec_minmax
, false);
5139 set_table_entry(&table
[9], "cache_nice_tries",
5140 &sd
->cache_nice_tries
,
5141 sizeof(int), 0644, proc_dointvec_minmax
, false);
5142 set_table_entry(&table
[10], "flags", &sd
->flags
,
5143 sizeof(int), 0644, proc_dointvec_minmax
, false);
5144 set_table_entry(&table
[11], "max_newidle_lb_cost",
5145 &sd
->max_newidle_lb_cost
,
5146 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5147 set_table_entry(&table
[12], "name", sd
->name
,
5148 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
5149 /* &table[13] is terminator */
5154 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5156 struct ctl_table
*entry
, *table
;
5157 struct sched_domain
*sd
;
5158 int domain_num
= 0, i
;
5161 for_each_domain(cpu
, sd
)
5163 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5168 for_each_domain(cpu
, sd
) {
5169 snprintf(buf
, 32, "domain%d", i
);
5170 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5172 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5179 static struct ctl_table_header
*sd_sysctl_header
;
5180 static void register_sched_domain_sysctl(void)
5182 int i
, cpu_num
= num_possible_cpus();
5183 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5186 WARN_ON(sd_ctl_dir
[0].child
);
5187 sd_ctl_dir
[0].child
= entry
;
5192 for_each_possible_cpu(i
) {
5193 snprintf(buf
, 32, "cpu%d", i
);
5194 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5196 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5200 WARN_ON(sd_sysctl_header
);
5201 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5204 /* may be called multiple times per register */
5205 static void unregister_sched_domain_sysctl(void)
5207 if (sd_sysctl_header
)
5208 unregister_sysctl_table(sd_sysctl_header
);
5209 sd_sysctl_header
= NULL
;
5210 if (sd_ctl_dir
[0].child
)
5211 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5214 static void register_sched_domain_sysctl(void)
5217 static void unregister_sched_domain_sysctl(void)
5222 static void set_rq_online(struct rq
*rq
)
5225 const struct sched_class
*class;
5227 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5230 for_each_class(class) {
5231 if (class->rq_online
)
5232 class->rq_online(rq
);
5237 static void set_rq_offline(struct rq
*rq
)
5240 const struct sched_class
*class;
5242 for_each_class(class) {
5243 if (class->rq_offline
)
5244 class->rq_offline(rq
);
5247 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5253 * migration_call - callback that gets triggered when a CPU is added.
5254 * Here we can start up the necessary migration thread for the new CPU.
5257 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5259 int cpu
= (long)hcpu
;
5260 unsigned long flags
;
5261 struct rq
*rq
= cpu_rq(cpu
);
5263 switch (action
& ~CPU_TASKS_FROZEN
) {
5265 case CPU_UP_PREPARE
:
5266 rq
->calc_load_update
= calc_load_update
;
5270 /* Update our root-domain */
5271 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5273 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5277 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5280 #ifdef CONFIG_HOTPLUG_CPU
5282 sched_ttwu_pending();
5283 /* Update our root-domain */
5284 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5286 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5290 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5291 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5295 calc_load_migrate(rq
);
5300 update_max_interval();
5306 * Register at high priority so that task migration (migrate_all_tasks)
5307 * happens before everything else. This has to be lower priority than
5308 * the notifier in the perf_event subsystem, though.
5310 static struct notifier_block migration_notifier
= {
5311 .notifier_call
= migration_call
,
5312 .priority
= CPU_PRI_MIGRATION
,
5315 static void __cpuinit
set_cpu_rq_start_time(void)
5317 int cpu
= smp_processor_id();
5318 struct rq
*rq
= cpu_rq(cpu
);
5319 rq
->age_stamp
= sched_clock_cpu(cpu
);
5322 static int sched_cpu_active(struct notifier_block
*nfb
,
5323 unsigned long action
, void *hcpu
)
5325 switch (action
& ~CPU_TASKS_FROZEN
) {
5327 set_cpu_rq_start_time();
5329 case CPU_DOWN_FAILED
:
5330 set_cpu_active((long)hcpu
, true);
5337 static int sched_cpu_inactive(struct notifier_block
*nfb
,
5338 unsigned long action
, void *hcpu
)
5340 unsigned long flags
;
5341 long cpu
= (long)hcpu
;
5344 switch (action
& ~CPU_TASKS_FROZEN
) {
5345 case CPU_DOWN_PREPARE
:
5346 set_cpu_active(cpu
, false);
5348 /* explicitly allow suspend */
5349 if (!(action
& CPU_TASKS_FROZEN
)) {
5353 rcu_read_lock_sched();
5354 dl_b
= dl_bw_of(cpu
);
5356 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
5357 cpus
= dl_bw_cpus(cpu
);
5358 overflow
= __dl_overflow(dl_b
, cpus
, 0, 0);
5359 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
5361 rcu_read_unlock_sched();
5364 return notifier_from_errno(-EBUSY
);
5372 static int __init
migration_init(void)
5374 void *cpu
= (void *)(long)smp_processor_id();
5377 /* Initialize migration for the boot CPU */
5378 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5379 BUG_ON(err
== NOTIFY_BAD
);
5380 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5381 register_cpu_notifier(&migration_notifier
);
5383 /* Register cpu active notifiers */
5384 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5385 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5389 early_initcall(migration_init
);
5394 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5396 #ifdef CONFIG_SCHED_DEBUG
5398 static __read_mostly
int sched_debug_enabled
;
5400 static int __init
sched_debug_setup(char *str
)
5402 sched_debug_enabled
= 1;
5406 early_param("sched_debug", sched_debug_setup
);
5408 static inline bool sched_debug(void)
5410 return sched_debug_enabled
;
5413 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5414 struct cpumask
*groupmask
)
5416 struct sched_group
*group
= sd
->groups
;
5418 cpumask_clear(groupmask
);
5420 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5422 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5423 printk("does not load-balance\n");
5425 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5430 printk(KERN_CONT
"span %*pbl level %s\n",
5431 cpumask_pr_args(sched_domain_span(sd
)), sd
->name
);
5433 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5434 printk(KERN_ERR
"ERROR: domain->span does not contain "
5437 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5438 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5442 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5446 printk(KERN_ERR
"ERROR: group is NULL\n");
5450 if (!cpumask_weight(sched_group_cpus(group
))) {
5451 printk(KERN_CONT
"\n");
5452 printk(KERN_ERR
"ERROR: empty group\n");
5456 if (!(sd
->flags
& SD_OVERLAP
) &&
5457 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5458 printk(KERN_CONT
"\n");
5459 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5463 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5465 printk(KERN_CONT
" %*pbl",
5466 cpumask_pr_args(sched_group_cpus(group
)));
5467 if (group
->sgc
->capacity
!= SCHED_CAPACITY_SCALE
) {
5468 printk(KERN_CONT
" (cpu_capacity = %d)",
5469 group
->sgc
->capacity
);
5472 group
= group
->next
;
5473 } while (group
!= sd
->groups
);
5474 printk(KERN_CONT
"\n");
5476 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5477 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5480 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5481 printk(KERN_ERR
"ERROR: parent span is not a superset "
5482 "of domain->span\n");
5486 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5490 if (!sched_debug_enabled
)
5494 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5498 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5501 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5509 #else /* !CONFIG_SCHED_DEBUG */
5510 # define sched_domain_debug(sd, cpu) do { } while (0)
5511 static inline bool sched_debug(void)
5515 #endif /* CONFIG_SCHED_DEBUG */
5517 static int sd_degenerate(struct sched_domain
*sd
)
5519 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5522 /* Following flags need at least 2 groups */
5523 if (sd
->flags
& (SD_LOAD_BALANCE
|
5524 SD_BALANCE_NEWIDLE
|
5527 SD_SHARE_CPUCAPACITY
|
5528 SD_SHARE_PKG_RESOURCES
|
5529 SD_SHARE_POWERDOMAIN
)) {
5530 if (sd
->groups
!= sd
->groups
->next
)
5534 /* Following flags don't use groups */
5535 if (sd
->flags
& (SD_WAKE_AFFINE
))
5542 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5544 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5546 if (sd_degenerate(parent
))
5549 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5552 /* Flags needing groups don't count if only 1 group in parent */
5553 if (parent
->groups
== parent
->groups
->next
) {
5554 pflags
&= ~(SD_LOAD_BALANCE
|
5555 SD_BALANCE_NEWIDLE
|
5558 SD_SHARE_CPUCAPACITY
|
5559 SD_SHARE_PKG_RESOURCES
|
5561 SD_SHARE_POWERDOMAIN
);
5562 if (nr_node_ids
== 1)
5563 pflags
&= ~SD_SERIALIZE
;
5565 if (~cflags
& pflags
)
5571 static void free_rootdomain(struct rcu_head
*rcu
)
5573 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5575 cpupri_cleanup(&rd
->cpupri
);
5576 cpudl_cleanup(&rd
->cpudl
);
5577 free_cpumask_var(rd
->dlo_mask
);
5578 free_cpumask_var(rd
->rto_mask
);
5579 free_cpumask_var(rd
->online
);
5580 free_cpumask_var(rd
->span
);
5584 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5586 struct root_domain
*old_rd
= NULL
;
5587 unsigned long flags
;
5589 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5594 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5597 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5600 * If we dont want to free the old_rd yet then
5601 * set old_rd to NULL to skip the freeing later
5604 if (!atomic_dec_and_test(&old_rd
->refcount
))
5608 atomic_inc(&rd
->refcount
);
5611 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5612 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5615 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5618 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5621 static int init_rootdomain(struct root_domain
*rd
)
5623 memset(rd
, 0, sizeof(*rd
));
5625 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5627 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5629 if (!alloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
5631 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5634 init_dl_bw(&rd
->dl_bw
);
5635 if (cpudl_init(&rd
->cpudl
) != 0)
5638 if (cpupri_init(&rd
->cpupri
) != 0)
5643 free_cpumask_var(rd
->rto_mask
);
5645 free_cpumask_var(rd
->dlo_mask
);
5647 free_cpumask_var(rd
->online
);
5649 free_cpumask_var(rd
->span
);
5655 * By default the system creates a single root-domain with all cpus as
5656 * members (mimicking the global state we have today).
5658 struct root_domain def_root_domain
;
5660 static void init_defrootdomain(void)
5662 init_rootdomain(&def_root_domain
);
5664 atomic_set(&def_root_domain
.refcount
, 1);
5667 static struct root_domain
*alloc_rootdomain(void)
5669 struct root_domain
*rd
;
5671 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5675 if (init_rootdomain(rd
) != 0) {
5683 static void free_sched_groups(struct sched_group
*sg
, int free_sgc
)
5685 struct sched_group
*tmp
, *first
;
5694 if (free_sgc
&& atomic_dec_and_test(&sg
->sgc
->ref
))
5699 } while (sg
!= first
);
5702 static void free_sched_domain(struct rcu_head
*rcu
)
5704 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5707 * If its an overlapping domain it has private groups, iterate and
5710 if (sd
->flags
& SD_OVERLAP
) {
5711 free_sched_groups(sd
->groups
, 1);
5712 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5713 kfree(sd
->groups
->sgc
);
5719 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5721 call_rcu(&sd
->rcu
, free_sched_domain
);
5724 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5726 for (; sd
; sd
= sd
->parent
)
5727 destroy_sched_domain(sd
, cpu
);
5731 * Keep a special pointer to the highest sched_domain that has
5732 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5733 * allows us to avoid some pointer chasing select_idle_sibling().
5735 * Also keep a unique ID per domain (we use the first cpu number in
5736 * the cpumask of the domain), this allows us to quickly tell if
5737 * two cpus are in the same cache domain, see cpus_share_cache().
5739 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5740 DEFINE_PER_CPU(int, sd_llc_size
);
5741 DEFINE_PER_CPU(int, sd_llc_id
);
5742 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
5743 DEFINE_PER_CPU(struct sched_domain
*, sd_busy
);
5744 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
5746 static void update_top_cache_domain(int cpu
)
5748 struct sched_domain
*sd
;
5749 struct sched_domain
*busy_sd
= NULL
;
5753 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5755 id
= cpumask_first(sched_domain_span(sd
));
5756 size
= cpumask_weight(sched_domain_span(sd
));
5757 busy_sd
= sd
->parent
; /* sd_busy */
5759 rcu_assign_pointer(per_cpu(sd_busy
, cpu
), busy_sd
);
5761 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5762 per_cpu(sd_llc_size
, cpu
) = size
;
5763 per_cpu(sd_llc_id
, cpu
) = id
;
5765 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
5766 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
5768 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
5769 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
5773 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5774 * hold the hotplug lock.
5777 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5779 struct rq
*rq
= cpu_rq(cpu
);
5780 struct sched_domain
*tmp
;
5782 /* Remove the sched domains which do not contribute to scheduling. */
5783 for (tmp
= sd
; tmp
; ) {
5784 struct sched_domain
*parent
= tmp
->parent
;
5788 if (sd_parent_degenerate(tmp
, parent
)) {
5789 tmp
->parent
= parent
->parent
;
5791 parent
->parent
->child
= tmp
;
5793 * Transfer SD_PREFER_SIBLING down in case of a
5794 * degenerate parent; the spans match for this
5795 * so the property transfers.
5797 if (parent
->flags
& SD_PREFER_SIBLING
)
5798 tmp
->flags
|= SD_PREFER_SIBLING
;
5799 destroy_sched_domain(parent
, cpu
);
5804 if (sd
&& sd_degenerate(sd
)) {
5807 destroy_sched_domain(tmp
, cpu
);
5812 sched_domain_debug(sd
, cpu
);
5814 rq_attach_root(rq
, rd
);
5816 rcu_assign_pointer(rq
->sd
, sd
);
5817 destroy_sched_domains(tmp
, cpu
);
5819 update_top_cache_domain(cpu
);
5822 /* cpus with isolated domains */
5823 static cpumask_var_t cpu_isolated_map
;
5825 /* Setup the mask of cpus configured for isolated domains */
5826 static int __init
isolated_cpu_setup(char *str
)
5828 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5829 cpulist_parse(str
, cpu_isolated_map
);
5833 __setup("isolcpus=", isolated_cpu_setup
);
5836 struct sched_domain
** __percpu sd
;
5837 struct root_domain
*rd
;
5848 * Build an iteration mask that can exclude certain CPUs from the upwards
5851 * Asymmetric node setups can result in situations where the domain tree is of
5852 * unequal depth, make sure to skip domains that already cover the entire
5855 * In that case build_sched_domains() will have terminated the iteration early
5856 * and our sibling sd spans will be empty. Domains should always include the
5857 * cpu they're built on, so check that.
5860 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5862 const struct cpumask
*span
= sched_domain_span(sd
);
5863 struct sd_data
*sdd
= sd
->private;
5864 struct sched_domain
*sibling
;
5867 for_each_cpu(i
, span
) {
5868 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5869 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5872 cpumask_set_cpu(i
, sched_group_mask(sg
));
5877 * Return the canonical balance cpu for this group, this is the first cpu
5878 * of this group that's also in the iteration mask.
5880 int group_balance_cpu(struct sched_group
*sg
)
5882 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5886 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5888 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5889 const struct cpumask
*span
= sched_domain_span(sd
);
5890 struct cpumask
*covered
= sched_domains_tmpmask
;
5891 struct sd_data
*sdd
= sd
->private;
5892 struct sched_domain
*sibling
;
5895 cpumask_clear(covered
);
5897 for_each_cpu(i
, span
) {
5898 struct cpumask
*sg_span
;
5900 if (cpumask_test_cpu(i
, covered
))
5903 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5905 /* See the comment near build_group_mask(). */
5906 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5909 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5910 GFP_KERNEL
, cpu_to_node(cpu
));
5915 sg_span
= sched_group_cpus(sg
);
5917 cpumask_copy(sg_span
, sched_domain_span(sibling
->child
));
5919 cpumask_set_cpu(i
, sg_span
);
5921 cpumask_or(covered
, covered
, sg_span
);
5923 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, i
);
5924 if (atomic_inc_return(&sg
->sgc
->ref
) == 1)
5925 build_group_mask(sd
, sg
);
5928 * Initialize sgc->capacity such that even if we mess up the
5929 * domains and no possible iteration will get us here, we won't
5932 sg
->sgc
->capacity
= SCHED_CAPACITY_SCALE
* cpumask_weight(sg_span
);
5935 * Make sure the first group of this domain contains the
5936 * canonical balance cpu. Otherwise the sched_domain iteration
5937 * breaks. See update_sg_lb_stats().
5939 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5940 group_balance_cpu(sg
) == cpu
)
5950 sd
->groups
= groups
;
5955 free_sched_groups(first
, 0);
5960 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5962 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5963 struct sched_domain
*child
= sd
->child
;
5966 cpu
= cpumask_first(sched_domain_span(child
));
5969 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5970 (*sg
)->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
5971 atomic_set(&(*sg
)->sgc
->ref
, 1); /* for claim_allocations */
5978 * build_sched_groups will build a circular linked list of the groups
5979 * covered by the given span, and will set each group's ->cpumask correctly,
5980 * and ->cpu_capacity to 0.
5982 * Assumes the sched_domain tree is fully constructed
5985 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5987 struct sched_group
*first
= NULL
, *last
= NULL
;
5988 struct sd_data
*sdd
= sd
->private;
5989 const struct cpumask
*span
= sched_domain_span(sd
);
5990 struct cpumask
*covered
;
5993 get_group(cpu
, sdd
, &sd
->groups
);
5994 atomic_inc(&sd
->groups
->ref
);
5996 if (cpu
!= cpumask_first(span
))
5999 lockdep_assert_held(&sched_domains_mutex
);
6000 covered
= sched_domains_tmpmask
;
6002 cpumask_clear(covered
);
6004 for_each_cpu(i
, span
) {
6005 struct sched_group
*sg
;
6008 if (cpumask_test_cpu(i
, covered
))
6011 group
= get_group(i
, sdd
, &sg
);
6012 cpumask_setall(sched_group_mask(sg
));
6014 for_each_cpu(j
, span
) {
6015 if (get_group(j
, sdd
, NULL
) != group
)
6018 cpumask_set_cpu(j
, covered
);
6019 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6034 * Initialize sched groups cpu_capacity.
6036 * cpu_capacity indicates the capacity of sched group, which is used while
6037 * distributing the load between different sched groups in a sched domain.
6038 * Typically cpu_capacity for all the groups in a sched domain will be same
6039 * unless there are asymmetries in the topology. If there are asymmetries,
6040 * group having more cpu_capacity will pickup more load compared to the
6041 * group having less cpu_capacity.
6043 static void init_sched_groups_capacity(int cpu
, struct sched_domain
*sd
)
6045 struct sched_group
*sg
= sd
->groups
;
6050 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
6052 } while (sg
!= sd
->groups
);
6054 if (cpu
!= group_balance_cpu(sg
))
6057 update_group_capacity(sd
, cpu
);
6058 atomic_set(&sg
->sgc
->nr_busy_cpus
, sg
->group_weight
);
6062 * Initializers for schedule domains
6063 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6066 static int default_relax_domain_level
= -1;
6067 int sched_domain_level_max
;
6069 static int __init
setup_relax_domain_level(char *str
)
6071 if (kstrtoint(str
, 0, &default_relax_domain_level
))
6072 pr_warn("Unable to set relax_domain_level\n");
6076 __setup("relax_domain_level=", setup_relax_domain_level
);
6078 static void set_domain_attribute(struct sched_domain
*sd
,
6079 struct sched_domain_attr
*attr
)
6083 if (!attr
|| attr
->relax_domain_level
< 0) {
6084 if (default_relax_domain_level
< 0)
6087 request
= default_relax_domain_level
;
6089 request
= attr
->relax_domain_level
;
6090 if (request
< sd
->level
) {
6091 /* turn off idle balance on this domain */
6092 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6094 /* turn on idle balance on this domain */
6095 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6099 static void __sdt_free(const struct cpumask
*cpu_map
);
6100 static int __sdt_alloc(const struct cpumask
*cpu_map
);
6102 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6103 const struct cpumask
*cpu_map
)
6107 if (!atomic_read(&d
->rd
->refcount
))
6108 free_rootdomain(&d
->rd
->rcu
); /* fall through */
6110 free_percpu(d
->sd
); /* fall through */
6112 __sdt_free(cpu_map
); /* fall through */
6118 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6119 const struct cpumask
*cpu_map
)
6121 memset(d
, 0, sizeof(*d
));
6123 if (__sdt_alloc(cpu_map
))
6124 return sa_sd_storage
;
6125 d
->sd
= alloc_percpu(struct sched_domain
*);
6127 return sa_sd_storage
;
6128 d
->rd
= alloc_rootdomain();
6131 return sa_rootdomain
;
6135 * NULL the sd_data elements we've used to build the sched_domain and
6136 * sched_group structure so that the subsequent __free_domain_allocs()
6137 * will not free the data we're using.
6139 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
6141 struct sd_data
*sdd
= sd
->private;
6143 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
6144 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
6146 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
6147 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
6149 if (atomic_read(&(*per_cpu_ptr(sdd
->sgc
, cpu
))->ref
))
6150 *per_cpu_ptr(sdd
->sgc
, cpu
) = NULL
;
6154 static int sched_domains_numa_levels
;
6155 enum numa_topology_type sched_numa_topology_type
;
6156 static int *sched_domains_numa_distance
;
6157 int sched_max_numa_distance
;
6158 static struct cpumask
***sched_domains_numa_masks
;
6159 static int sched_domains_curr_level
;
6163 * SD_flags allowed in topology descriptions.
6165 * SD_SHARE_CPUCAPACITY - describes SMT topologies
6166 * SD_SHARE_PKG_RESOURCES - describes shared caches
6167 * SD_NUMA - describes NUMA topologies
6168 * SD_SHARE_POWERDOMAIN - describes shared power domain
6171 * SD_ASYM_PACKING - describes SMT quirks
6173 #define TOPOLOGY_SD_FLAGS \
6174 (SD_SHARE_CPUCAPACITY | \
6175 SD_SHARE_PKG_RESOURCES | \
6178 SD_SHARE_POWERDOMAIN)
6180 static struct sched_domain
*
6181 sd_init(struct sched_domain_topology_level
*tl
, int cpu
)
6183 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
6184 int sd_weight
, sd_flags
= 0;
6188 * Ugly hack to pass state to sd_numa_mask()...
6190 sched_domains_curr_level
= tl
->numa_level
;
6193 sd_weight
= cpumask_weight(tl
->mask(cpu
));
6196 sd_flags
= (*tl
->sd_flags
)();
6197 if (WARN_ONCE(sd_flags
& ~TOPOLOGY_SD_FLAGS
,
6198 "wrong sd_flags in topology description\n"))
6199 sd_flags
&= ~TOPOLOGY_SD_FLAGS
;
6201 *sd
= (struct sched_domain
){
6202 .min_interval
= sd_weight
,
6203 .max_interval
= 2*sd_weight
,
6205 .imbalance_pct
= 125,
6207 .cache_nice_tries
= 0,
6214 .flags
= 1*SD_LOAD_BALANCE
6215 | 1*SD_BALANCE_NEWIDLE
6220 | 0*SD_SHARE_CPUCAPACITY
6221 | 0*SD_SHARE_PKG_RESOURCES
6223 | 0*SD_PREFER_SIBLING
6228 .last_balance
= jiffies
,
6229 .balance_interval
= sd_weight
,
6231 .max_newidle_lb_cost
= 0,
6232 .next_decay_max_lb_cost
= jiffies
,
6233 #ifdef CONFIG_SCHED_DEBUG
6239 * Convert topological properties into behaviour.
6242 if (sd
->flags
& SD_SHARE_CPUCAPACITY
) {
6243 sd
->flags
|= SD_PREFER_SIBLING
;
6244 sd
->imbalance_pct
= 110;
6245 sd
->smt_gain
= 1178; /* ~15% */
6247 } else if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
6248 sd
->imbalance_pct
= 117;
6249 sd
->cache_nice_tries
= 1;
6253 } else if (sd
->flags
& SD_NUMA
) {
6254 sd
->cache_nice_tries
= 2;
6258 sd
->flags
|= SD_SERIALIZE
;
6259 if (sched_domains_numa_distance
[tl
->numa_level
] > RECLAIM_DISTANCE
) {
6260 sd
->flags
&= ~(SD_BALANCE_EXEC
|
6267 sd
->flags
|= SD_PREFER_SIBLING
;
6268 sd
->cache_nice_tries
= 1;
6273 sd
->private = &tl
->data
;
6279 * Topology list, bottom-up.
6281 static struct sched_domain_topology_level default_topology
[] = {
6282 #ifdef CONFIG_SCHED_SMT
6283 { cpu_smt_mask
, cpu_smt_flags
, SD_INIT_NAME(SMT
) },
6285 #ifdef CONFIG_SCHED_MC
6286 { cpu_coregroup_mask
, cpu_core_flags
, SD_INIT_NAME(MC
) },
6288 { cpu_cpu_mask
, SD_INIT_NAME(DIE
) },
6292 struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6294 #define for_each_sd_topology(tl) \
6295 for (tl = sched_domain_topology; tl->mask; tl++)
6297 void set_sched_topology(struct sched_domain_topology_level
*tl
)
6299 sched_domain_topology
= tl
;
6304 static const struct cpumask
*sd_numa_mask(int cpu
)
6306 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6309 static void sched_numa_warn(const char *str
)
6311 static int done
= false;
6319 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6321 for (i
= 0; i
< nr_node_ids
; i
++) {
6322 printk(KERN_WARNING
" ");
6323 for (j
= 0; j
< nr_node_ids
; j
++)
6324 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6325 printk(KERN_CONT
"\n");
6327 printk(KERN_WARNING
"\n");
6330 bool find_numa_distance(int distance
)
6334 if (distance
== node_distance(0, 0))
6337 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6338 if (sched_domains_numa_distance
[i
] == distance
)
6346 * A system can have three types of NUMA topology:
6347 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
6348 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
6349 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
6351 * The difference between a glueless mesh topology and a backplane
6352 * topology lies in whether communication between not directly
6353 * connected nodes goes through intermediary nodes (where programs
6354 * could run), or through backplane controllers. This affects
6355 * placement of programs.
6357 * The type of topology can be discerned with the following tests:
6358 * - If the maximum distance between any nodes is 1 hop, the system
6359 * is directly connected.
6360 * - If for two nodes A and B, located N > 1 hops away from each other,
6361 * there is an intermediary node C, which is < N hops away from both
6362 * nodes A and B, the system is a glueless mesh.
6364 static void init_numa_topology_type(void)
6368 n
= sched_max_numa_distance
;
6371 sched_numa_topology_type
= NUMA_DIRECT
;
6373 for_each_online_node(a
) {
6374 for_each_online_node(b
) {
6375 /* Find two nodes furthest removed from each other. */
6376 if (node_distance(a
, b
) < n
)
6379 /* Is there an intermediary node between a and b? */
6380 for_each_online_node(c
) {
6381 if (node_distance(a
, c
) < n
&&
6382 node_distance(b
, c
) < n
) {
6383 sched_numa_topology_type
=
6389 sched_numa_topology_type
= NUMA_BACKPLANE
;
6395 static void sched_init_numa(void)
6397 int next_distance
, curr_distance
= node_distance(0, 0);
6398 struct sched_domain_topology_level
*tl
;
6402 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6403 if (!sched_domains_numa_distance
)
6407 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6408 * unique distances in the node_distance() table.
6410 * Assumes node_distance(0,j) includes all distances in
6411 * node_distance(i,j) in order to avoid cubic time.
6413 next_distance
= curr_distance
;
6414 for (i
= 0; i
< nr_node_ids
; i
++) {
6415 for (j
= 0; j
< nr_node_ids
; j
++) {
6416 for (k
= 0; k
< nr_node_ids
; k
++) {
6417 int distance
= node_distance(i
, k
);
6419 if (distance
> curr_distance
&&
6420 (distance
< next_distance
||
6421 next_distance
== curr_distance
))
6422 next_distance
= distance
;
6425 * While not a strong assumption it would be nice to know
6426 * about cases where if node A is connected to B, B is not
6427 * equally connected to A.
6429 if (sched_debug() && node_distance(k
, i
) != distance
)
6430 sched_numa_warn("Node-distance not symmetric");
6432 if (sched_debug() && i
&& !find_numa_distance(distance
))
6433 sched_numa_warn("Node-0 not representative");
6435 if (next_distance
!= curr_distance
) {
6436 sched_domains_numa_distance
[level
++] = next_distance
;
6437 sched_domains_numa_levels
= level
;
6438 curr_distance
= next_distance
;
6443 * In case of sched_debug() we verify the above assumption.
6453 * 'level' contains the number of unique distances, excluding the
6454 * identity distance node_distance(i,i).
6456 * The sched_domains_numa_distance[] array includes the actual distance
6461 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6462 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6463 * the array will contain less then 'level' members. This could be
6464 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6465 * in other functions.
6467 * We reset it to 'level' at the end of this function.
6469 sched_domains_numa_levels
= 0;
6471 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6472 if (!sched_domains_numa_masks
)
6476 * Now for each level, construct a mask per node which contains all
6477 * cpus of nodes that are that many hops away from us.
6479 for (i
= 0; i
< level
; i
++) {
6480 sched_domains_numa_masks
[i
] =
6481 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6482 if (!sched_domains_numa_masks
[i
])
6485 for (j
= 0; j
< nr_node_ids
; j
++) {
6486 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6490 sched_domains_numa_masks
[i
][j
] = mask
;
6492 for (k
= 0; k
< nr_node_ids
; k
++) {
6493 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6496 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6501 /* Compute default topology size */
6502 for (i
= 0; sched_domain_topology
[i
].mask
; i
++);
6504 tl
= kzalloc((i
+ level
+ 1) *
6505 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6510 * Copy the default topology bits..
6512 for (i
= 0; sched_domain_topology
[i
].mask
; i
++)
6513 tl
[i
] = sched_domain_topology
[i
];
6516 * .. and append 'j' levels of NUMA goodness.
6518 for (j
= 0; j
< level
; i
++, j
++) {
6519 tl
[i
] = (struct sched_domain_topology_level
){
6520 .mask
= sd_numa_mask
,
6521 .sd_flags
= cpu_numa_flags
,
6522 .flags
= SDTL_OVERLAP
,
6528 sched_domain_topology
= tl
;
6530 sched_domains_numa_levels
= level
;
6531 sched_max_numa_distance
= sched_domains_numa_distance
[level
- 1];
6533 init_numa_topology_type();
6536 static void sched_domains_numa_masks_set(int cpu
)
6539 int node
= cpu_to_node(cpu
);
6541 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6542 for (j
= 0; j
< nr_node_ids
; j
++) {
6543 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6544 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6549 static void sched_domains_numa_masks_clear(int cpu
)
6552 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6553 for (j
= 0; j
< nr_node_ids
; j
++)
6554 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6559 * Update sched_domains_numa_masks[level][node] array when new cpus
6562 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6563 unsigned long action
,
6566 int cpu
= (long)hcpu
;
6568 switch (action
& ~CPU_TASKS_FROZEN
) {
6570 sched_domains_numa_masks_set(cpu
);
6574 sched_domains_numa_masks_clear(cpu
);
6584 static inline void sched_init_numa(void)
6588 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6589 unsigned long action
,
6594 #endif /* CONFIG_NUMA */
6596 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6598 struct sched_domain_topology_level
*tl
;
6601 for_each_sd_topology(tl
) {
6602 struct sd_data
*sdd
= &tl
->data
;
6604 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6608 sdd
->sg
= alloc_percpu(struct sched_group
*);
6612 sdd
->sgc
= alloc_percpu(struct sched_group_capacity
*);
6616 for_each_cpu(j
, cpu_map
) {
6617 struct sched_domain
*sd
;
6618 struct sched_group
*sg
;
6619 struct sched_group_capacity
*sgc
;
6621 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6622 GFP_KERNEL
, cpu_to_node(j
));
6626 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6628 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6629 GFP_KERNEL
, cpu_to_node(j
));
6635 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6637 sgc
= kzalloc_node(sizeof(struct sched_group_capacity
) + cpumask_size(),
6638 GFP_KERNEL
, cpu_to_node(j
));
6642 *per_cpu_ptr(sdd
->sgc
, j
) = sgc
;
6649 static void __sdt_free(const struct cpumask
*cpu_map
)
6651 struct sched_domain_topology_level
*tl
;
6654 for_each_sd_topology(tl
) {
6655 struct sd_data
*sdd
= &tl
->data
;
6657 for_each_cpu(j
, cpu_map
) {
6658 struct sched_domain
*sd
;
6661 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6662 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6663 free_sched_groups(sd
->groups
, 0);
6664 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6668 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6670 kfree(*per_cpu_ptr(sdd
->sgc
, j
));
6672 free_percpu(sdd
->sd
);
6674 free_percpu(sdd
->sg
);
6676 free_percpu(sdd
->sgc
);
6681 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6682 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6683 struct sched_domain
*child
, int cpu
)
6685 struct sched_domain
*sd
= sd_init(tl
, cpu
);
6689 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6691 sd
->level
= child
->level
+ 1;
6692 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6696 if (!cpumask_subset(sched_domain_span(child
),
6697 sched_domain_span(sd
))) {
6698 pr_err("BUG: arch topology borken\n");
6699 #ifdef CONFIG_SCHED_DEBUG
6700 pr_err(" the %s domain not a subset of the %s domain\n",
6701 child
->name
, sd
->name
);
6703 /* Fixup, ensure @sd has at least @child cpus. */
6704 cpumask_or(sched_domain_span(sd
),
6705 sched_domain_span(sd
),
6706 sched_domain_span(child
));
6710 set_domain_attribute(sd
, attr
);
6716 * Build sched domains for a given set of cpus and attach the sched domains
6717 * to the individual cpus
6719 static int build_sched_domains(const struct cpumask
*cpu_map
,
6720 struct sched_domain_attr
*attr
)
6722 enum s_alloc alloc_state
;
6723 struct sched_domain
*sd
;
6725 int i
, ret
= -ENOMEM
;
6727 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6728 if (alloc_state
!= sa_rootdomain
)
6731 /* Set up domains for cpus specified by the cpu_map. */
6732 for_each_cpu(i
, cpu_map
) {
6733 struct sched_domain_topology_level
*tl
;
6736 for_each_sd_topology(tl
) {
6737 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6738 if (tl
== sched_domain_topology
)
6739 *per_cpu_ptr(d
.sd
, i
) = sd
;
6740 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6741 sd
->flags
|= SD_OVERLAP
;
6742 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6747 /* Build the groups for the domains */
6748 for_each_cpu(i
, cpu_map
) {
6749 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6750 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6751 if (sd
->flags
& SD_OVERLAP
) {
6752 if (build_overlap_sched_groups(sd
, i
))
6755 if (build_sched_groups(sd
, i
))
6761 /* Calculate CPU capacity for physical packages and nodes */
6762 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6763 if (!cpumask_test_cpu(i
, cpu_map
))
6766 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6767 claim_allocations(i
, sd
);
6768 init_sched_groups_capacity(i
, sd
);
6772 /* Attach the domains */
6774 for_each_cpu(i
, cpu_map
) {
6775 sd
= *per_cpu_ptr(d
.sd
, i
);
6776 cpu_attach_domain(sd
, d
.rd
, i
);
6782 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6786 static cpumask_var_t
*doms_cur
; /* current sched domains */
6787 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6788 static struct sched_domain_attr
*dattr_cur
;
6789 /* attribues of custom domains in 'doms_cur' */
6792 * Special case: If a kmalloc of a doms_cur partition (array of
6793 * cpumask) fails, then fallback to a single sched domain,
6794 * as determined by the single cpumask fallback_doms.
6796 static cpumask_var_t fallback_doms
;
6799 * arch_update_cpu_topology lets virtualized architectures update the
6800 * cpu core maps. It is supposed to return 1 if the topology changed
6801 * or 0 if it stayed the same.
6803 int __weak
arch_update_cpu_topology(void)
6808 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6811 cpumask_var_t
*doms
;
6813 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6816 for (i
= 0; i
< ndoms
; i
++) {
6817 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6818 free_sched_domains(doms
, i
);
6825 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6828 for (i
= 0; i
< ndoms
; i
++)
6829 free_cpumask_var(doms
[i
]);
6834 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6835 * For now this just excludes isolated cpus, but could be used to
6836 * exclude other special cases in the future.
6838 static int init_sched_domains(const struct cpumask
*cpu_map
)
6842 arch_update_cpu_topology();
6844 doms_cur
= alloc_sched_domains(ndoms_cur
);
6846 doms_cur
= &fallback_doms
;
6847 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6848 err
= build_sched_domains(doms_cur
[0], NULL
);
6849 register_sched_domain_sysctl();
6855 * Detach sched domains from a group of cpus specified in cpu_map
6856 * These cpus will now be attached to the NULL domain
6858 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6863 for_each_cpu(i
, cpu_map
)
6864 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6868 /* handle null as "default" */
6869 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6870 struct sched_domain_attr
*new, int idx_new
)
6872 struct sched_domain_attr tmp
;
6879 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6880 new ? (new + idx_new
) : &tmp
,
6881 sizeof(struct sched_domain_attr
));
6885 * Partition sched domains as specified by the 'ndoms_new'
6886 * cpumasks in the array doms_new[] of cpumasks. This compares
6887 * doms_new[] to the current sched domain partitioning, doms_cur[].
6888 * It destroys each deleted domain and builds each new domain.
6890 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6891 * The masks don't intersect (don't overlap.) We should setup one
6892 * sched domain for each mask. CPUs not in any of the cpumasks will
6893 * not be load balanced. If the same cpumask appears both in the
6894 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6897 * The passed in 'doms_new' should be allocated using
6898 * alloc_sched_domains. This routine takes ownership of it and will
6899 * free_sched_domains it when done with it. If the caller failed the
6900 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6901 * and partition_sched_domains() will fallback to the single partition
6902 * 'fallback_doms', it also forces the domains to be rebuilt.
6904 * If doms_new == NULL it will be replaced with cpu_online_mask.
6905 * ndoms_new == 0 is a special case for destroying existing domains,
6906 * and it will not create the default domain.
6908 * Call with hotplug lock held
6910 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6911 struct sched_domain_attr
*dattr_new
)
6916 mutex_lock(&sched_domains_mutex
);
6918 /* always unregister in case we don't destroy any domains */
6919 unregister_sched_domain_sysctl();
6921 /* Let architecture update cpu core mappings. */
6922 new_topology
= arch_update_cpu_topology();
6924 n
= doms_new
? ndoms_new
: 0;
6926 /* Destroy deleted domains */
6927 for (i
= 0; i
< ndoms_cur
; i
++) {
6928 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6929 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6930 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6933 /* no match - a current sched domain not in new doms_new[] */
6934 detach_destroy_domains(doms_cur
[i
]);
6940 if (doms_new
== NULL
) {
6942 doms_new
= &fallback_doms
;
6943 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6944 WARN_ON_ONCE(dattr_new
);
6947 /* Build new domains */
6948 for (i
= 0; i
< ndoms_new
; i
++) {
6949 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6950 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6951 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6954 /* no match - add a new doms_new */
6955 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6960 /* Remember the new sched domains */
6961 if (doms_cur
!= &fallback_doms
)
6962 free_sched_domains(doms_cur
, ndoms_cur
);
6963 kfree(dattr_cur
); /* kfree(NULL) is safe */
6964 doms_cur
= doms_new
;
6965 dattr_cur
= dattr_new
;
6966 ndoms_cur
= ndoms_new
;
6968 register_sched_domain_sysctl();
6970 mutex_unlock(&sched_domains_mutex
);
6973 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6976 * Update cpusets according to cpu_active mask. If cpusets are
6977 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6978 * around partition_sched_domains().
6980 * If we come here as part of a suspend/resume, don't touch cpusets because we
6981 * want to restore it back to its original state upon resume anyway.
6983 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6987 case CPU_ONLINE_FROZEN
:
6988 case CPU_DOWN_FAILED_FROZEN
:
6991 * num_cpus_frozen tracks how many CPUs are involved in suspend
6992 * resume sequence. As long as this is not the last online
6993 * operation in the resume sequence, just build a single sched
6994 * domain, ignoring cpusets.
6997 if (likely(num_cpus_frozen
)) {
6998 partition_sched_domains(1, NULL
, NULL
);
7003 * This is the last CPU online operation. So fall through and
7004 * restore the original sched domains by considering the
7005 * cpuset configurations.
7009 case CPU_DOWN_FAILED
:
7010 cpuset_update_active_cpus(true);
7018 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7022 case CPU_DOWN_PREPARE
:
7023 cpuset_update_active_cpus(false);
7025 case CPU_DOWN_PREPARE_FROZEN
:
7027 partition_sched_domains(1, NULL
, NULL
);
7035 void __init
sched_init_smp(void)
7037 cpumask_var_t non_isolated_cpus
;
7039 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7040 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7045 * There's no userspace yet to cause hotplug operations; hence all the
7046 * cpu masks are stable and all blatant races in the below code cannot
7049 mutex_lock(&sched_domains_mutex
);
7050 init_sched_domains(cpu_active_mask
);
7051 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7052 if (cpumask_empty(non_isolated_cpus
))
7053 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7054 mutex_unlock(&sched_domains_mutex
);
7056 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
7057 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7058 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7062 /* Move init over to a non-isolated CPU */
7063 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7065 sched_init_granularity();
7066 free_cpumask_var(non_isolated_cpus
);
7068 init_sched_rt_class();
7069 init_sched_dl_class();
7072 void __init
sched_init_smp(void)
7074 sched_init_granularity();
7076 #endif /* CONFIG_SMP */
7078 const_debug
unsigned int sysctl_timer_migration
= 1;
7080 int in_sched_functions(unsigned long addr
)
7082 return in_lock_functions(addr
) ||
7083 (addr
>= (unsigned long)__sched_text_start
7084 && addr
< (unsigned long)__sched_text_end
);
7087 #ifdef CONFIG_CGROUP_SCHED
7089 * Default task group.
7090 * Every task in system belongs to this group at bootup.
7092 struct task_group root_task_group
;
7093 LIST_HEAD(task_groups
);
7096 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
7098 void __init
sched_init(void)
7101 unsigned long alloc_size
= 0, ptr
;
7103 #ifdef CONFIG_FAIR_GROUP_SCHED
7104 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7106 #ifdef CONFIG_RT_GROUP_SCHED
7107 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7110 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
7112 #ifdef CONFIG_FAIR_GROUP_SCHED
7113 root_task_group
.se
= (struct sched_entity
**)ptr
;
7114 ptr
+= nr_cpu_ids
* sizeof(void **);
7116 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7117 ptr
+= nr_cpu_ids
* sizeof(void **);
7119 #endif /* CONFIG_FAIR_GROUP_SCHED */
7120 #ifdef CONFIG_RT_GROUP_SCHED
7121 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7122 ptr
+= nr_cpu_ids
* sizeof(void **);
7124 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7125 ptr
+= nr_cpu_ids
* sizeof(void **);
7127 #endif /* CONFIG_RT_GROUP_SCHED */
7129 #ifdef CONFIG_CPUMASK_OFFSTACK
7130 for_each_possible_cpu(i
) {
7131 per_cpu(load_balance_mask
, i
) = (cpumask_var_t
)kzalloc_node(
7132 cpumask_size(), GFP_KERNEL
, cpu_to_node(i
));
7134 #endif /* CONFIG_CPUMASK_OFFSTACK */
7136 init_rt_bandwidth(&def_rt_bandwidth
,
7137 global_rt_period(), global_rt_runtime());
7138 init_dl_bandwidth(&def_dl_bandwidth
,
7139 global_rt_period(), global_rt_runtime());
7142 init_defrootdomain();
7145 #ifdef CONFIG_RT_GROUP_SCHED
7146 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7147 global_rt_period(), global_rt_runtime());
7148 #endif /* CONFIG_RT_GROUP_SCHED */
7150 #ifdef CONFIG_CGROUP_SCHED
7151 list_add(&root_task_group
.list
, &task_groups
);
7152 INIT_LIST_HEAD(&root_task_group
.children
);
7153 INIT_LIST_HEAD(&root_task_group
.siblings
);
7154 autogroup_init(&init_task
);
7156 #endif /* CONFIG_CGROUP_SCHED */
7158 for_each_possible_cpu(i
) {
7162 raw_spin_lock_init(&rq
->lock
);
7164 rq
->calc_load_active
= 0;
7165 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
7166 init_cfs_rq(&rq
->cfs
);
7167 init_rt_rq(&rq
->rt
);
7168 init_dl_rq(&rq
->dl
);
7169 #ifdef CONFIG_FAIR_GROUP_SCHED
7170 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
7171 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7173 * How much cpu bandwidth does root_task_group get?
7175 * In case of task-groups formed thr' the cgroup filesystem, it
7176 * gets 100% of the cpu resources in the system. This overall
7177 * system cpu resource is divided among the tasks of
7178 * root_task_group and its child task-groups in a fair manner,
7179 * based on each entity's (task or task-group's) weight
7180 * (se->load.weight).
7182 * In other words, if root_task_group has 10 tasks of weight
7183 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7184 * then A0's share of the cpu resource is:
7186 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7188 * We achieve this by letting root_task_group's tasks sit
7189 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7191 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
7192 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
7193 #endif /* CONFIG_FAIR_GROUP_SCHED */
7195 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7196 #ifdef CONFIG_RT_GROUP_SCHED
7197 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
7200 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7201 rq
->cpu_load
[j
] = 0;
7203 rq
->last_load_update_tick
= jiffies
;
7208 rq
->cpu_capacity
= rq
->cpu_capacity_orig
= SCHED_CAPACITY_SCALE
;
7209 rq
->post_schedule
= 0;
7210 rq
->active_balance
= 0;
7211 rq
->next_balance
= jiffies
;
7216 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7217 rq
->max_idle_balance_cost
= sysctl_sched_migration_cost
;
7219 INIT_LIST_HEAD(&rq
->cfs_tasks
);
7221 rq_attach_root(rq
, &def_root_domain
);
7222 #ifdef CONFIG_NO_HZ_COMMON
7225 #ifdef CONFIG_NO_HZ_FULL
7226 rq
->last_sched_tick
= 0;
7230 atomic_set(&rq
->nr_iowait
, 0);
7233 set_load_weight(&init_task
);
7235 #ifdef CONFIG_PREEMPT_NOTIFIERS
7236 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7240 * The boot idle thread does lazy MMU switching as well:
7242 atomic_inc(&init_mm
.mm_count
);
7243 enter_lazy_tlb(&init_mm
, current
);
7246 * During early bootup we pretend to be a normal task:
7248 current
->sched_class
= &fair_sched_class
;
7251 * Make us the idle thread. Technically, schedule() should not be
7252 * called from this thread, however somewhere below it might be,
7253 * but because we are the idle thread, we just pick up running again
7254 * when this runqueue becomes "idle".
7256 init_idle(current
, smp_processor_id());
7258 calc_load_update
= jiffies
+ LOAD_FREQ
;
7261 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
7262 /* May be allocated at isolcpus cmdline parse time */
7263 if (cpu_isolated_map
== NULL
)
7264 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7265 idle_thread_set_boot_cpu();
7266 set_cpu_rq_start_time();
7268 init_sched_fair_class();
7270 scheduler_running
= 1;
7273 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7274 static inline int preempt_count_equals(int preempt_offset
)
7276 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7278 return (nested
== preempt_offset
);
7281 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7284 * Blocking primitives will set (and therefore destroy) current->state,
7285 * since we will exit with TASK_RUNNING make sure we enter with it,
7286 * otherwise we will destroy state.
7288 WARN_ONCE(current
->state
!= TASK_RUNNING
&& current
->task_state_change
,
7289 "do not call blocking ops when !TASK_RUNNING; "
7290 "state=%lx set at [<%p>] %pS\n",
7292 (void *)current
->task_state_change
,
7293 (void *)current
->task_state_change
);
7295 ___might_sleep(file
, line
, preempt_offset
);
7297 EXPORT_SYMBOL(__might_sleep
);
7299 void ___might_sleep(const char *file
, int line
, int preempt_offset
)
7301 static unsigned long prev_jiffy
; /* ratelimiting */
7303 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7304 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled() &&
7305 !is_idle_task(current
)) ||
7306 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7308 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7310 prev_jiffy
= jiffies
;
7313 "BUG: sleeping function called from invalid context at %s:%d\n",
7316 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7317 in_atomic(), irqs_disabled(),
7318 current
->pid
, current
->comm
);
7320 if (task_stack_end_corrupted(current
))
7321 printk(KERN_EMERG
"Thread overran stack, or stack corrupted\n");
7323 debug_show_held_locks(current
);
7324 if (irqs_disabled())
7325 print_irqtrace_events(current
);
7326 #ifdef CONFIG_DEBUG_PREEMPT
7327 if (!preempt_count_equals(preempt_offset
)) {
7328 pr_err("Preemption disabled at:");
7329 print_ip_sym(current
->preempt_disable_ip
);
7335 EXPORT_SYMBOL(___might_sleep
);
7338 #ifdef CONFIG_MAGIC_SYSRQ
7339 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7341 const struct sched_class
*prev_class
= p
->sched_class
;
7342 struct sched_attr attr
= {
7343 .sched_policy
= SCHED_NORMAL
,
7345 int old_prio
= p
->prio
;
7348 queued
= task_on_rq_queued(p
);
7350 dequeue_task(rq
, p
, 0);
7351 __setscheduler(rq
, p
, &attr
);
7353 enqueue_task(rq
, p
, 0);
7357 check_class_changed(rq
, p
, prev_class
, old_prio
);
7360 void normalize_rt_tasks(void)
7362 struct task_struct
*g
, *p
;
7363 unsigned long flags
;
7366 read_lock(&tasklist_lock
);
7367 for_each_process_thread(g
, p
) {
7369 * Only normalize user tasks:
7371 if (p
->flags
& PF_KTHREAD
)
7374 p
->se
.exec_start
= 0;
7375 #ifdef CONFIG_SCHEDSTATS
7376 p
->se
.statistics
.wait_start
= 0;
7377 p
->se
.statistics
.sleep_start
= 0;
7378 p
->se
.statistics
.block_start
= 0;
7381 if (!dl_task(p
) && !rt_task(p
)) {
7383 * Renice negative nice level userspace
7386 if (task_nice(p
) < 0)
7387 set_user_nice(p
, 0);
7391 rq
= task_rq_lock(p
, &flags
);
7392 normalize_task(rq
, p
);
7393 task_rq_unlock(rq
, p
, &flags
);
7395 read_unlock(&tasklist_lock
);
7398 #endif /* CONFIG_MAGIC_SYSRQ */
7400 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7402 * These functions are only useful for the IA64 MCA handling, or kdb.
7404 * They can only be called when the whole system has been
7405 * stopped - every CPU needs to be quiescent, and no scheduling
7406 * activity can take place. Using them for anything else would
7407 * be a serious bug, and as a result, they aren't even visible
7408 * under any other configuration.
7412 * curr_task - return the current task for a given cpu.
7413 * @cpu: the processor in question.
7415 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7417 * Return: The current task for @cpu.
7419 struct task_struct
*curr_task(int cpu
)
7421 return cpu_curr(cpu
);
7424 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7428 * set_curr_task - set the current task for a given cpu.
7429 * @cpu: the processor in question.
7430 * @p: the task pointer to set.
7432 * Description: This function must only be used when non-maskable interrupts
7433 * are serviced on a separate stack. It allows the architecture to switch the
7434 * notion of the current task on a cpu in a non-blocking manner. This function
7435 * must be called with all CPU's synchronized, and interrupts disabled, the
7436 * and caller must save the original value of the current task (see
7437 * curr_task() above) and restore that value before reenabling interrupts and
7438 * re-starting the system.
7440 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7442 void set_curr_task(int cpu
, struct task_struct
*p
)
7449 #ifdef CONFIG_CGROUP_SCHED
7450 /* task_group_lock serializes the addition/removal of task groups */
7451 static DEFINE_SPINLOCK(task_group_lock
);
7453 static void free_sched_group(struct task_group
*tg
)
7455 free_fair_sched_group(tg
);
7456 free_rt_sched_group(tg
);
7461 /* allocate runqueue etc for a new task group */
7462 struct task_group
*sched_create_group(struct task_group
*parent
)
7464 struct task_group
*tg
;
7466 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7468 return ERR_PTR(-ENOMEM
);
7470 if (!alloc_fair_sched_group(tg
, parent
))
7473 if (!alloc_rt_sched_group(tg
, parent
))
7479 free_sched_group(tg
);
7480 return ERR_PTR(-ENOMEM
);
7483 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
7485 unsigned long flags
;
7487 spin_lock_irqsave(&task_group_lock
, flags
);
7488 list_add_rcu(&tg
->list
, &task_groups
);
7490 WARN_ON(!parent
); /* root should already exist */
7492 tg
->parent
= parent
;
7493 INIT_LIST_HEAD(&tg
->children
);
7494 list_add_rcu(&tg
->siblings
, &parent
->children
);
7495 spin_unlock_irqrestore(&task_group_lock
, flags
);
7498 /* rcu callback to free various structures associated with a task group */
7499 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7501 /* now it should be safe to free those cfs_rqs */
7502 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7505 /* Destroy runqueue etc associated with a task group */
7506 void sched_destroy_group(struct task_group
*tg
)
7508 /* wait for possible concurrent references to cfs_rqs complete */
7509 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7512 void sched_offline_group(struct task_group
*tg
)
7514 unsigned long flags
;
7517 /* end participation in shares distribution */
7518 for_each_possible_cpu(i
)
7519 unregister_fair_sched_group(tg
, i
);
7521 spin_lock_irqsave(&task_group_lock
, flags
);
7522 list_del_rcu(&tg
->list
);
7523 list_del_rcu(&tg
->siblings
);
7524 spin_unlock_irqrestore(&task_group_lock
, flags
);
7527 /* change task's runqueue when it moves between groups.
7528 * The caller of this function should have put the task in its new group
7529 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7530 * reflect its new group.
7532 void sched_move_task(struct task_struct
*tsk
)
7534 struct task_group
*tg
;
7535 int queued
, running
;
7536 unsigned long flags
;
7539 rq
= task_rq_lock(tsk
, &flags
);
7541 running
= task_current(rq
, tsk
);
7542 queued
= task_on_rq_queued(tsk
);
7545 dequeue_task(rq
, tsk
, 0);
7546 if (unlikely(running
))
7547 put_prev_task(rq
, tsk
);
7550 * All callers are synchronized by task_rq_lock(); we do not use RCU
7551 * which is pointless here. Thus, we pass "true" to task_css_check()
7552 * to prevent lockdep warnings.
7554 tg
= container_of(task_css_check(tsk
, cpu_cgrp_id
, true),
7555 struct task_group
, css
);
7556 tg
= autogroup_task_group(tsk
, tg
);
7557 tsk
->sched_task_group
= tg
;
7559 #ifdef CONFIG_FAIR_GROUP_SCHED
7560 if (tsk
->sched_class
->task_move_group
)
7561 tsk
->sched_class
->task_move_group(tsk
, queued
);
7564 set_task_rq(tsk
, task_cpu(tsk
));
7566 if (unlikely(running
))
7567 tsk
->sched_class
->set_curr_task(rq
);
7569 enqueue_task(rq
, tsk
, 0);
7571 task_rq_unlock(rq
, tsk
, &flags
);
7573 #endif /* CONFIG_CGROUP_SCHED */
7575 #ifdef CONFIG_RT_GROUP_SCHED
7577 * Ensure that the real time constraints are schedulable.
7579 static DEFINE_MUTEX(rt_constraints_mutex
);
7581 /* Must be called with tasklist_lock held */
7582 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7584 struct task_struct
*g
, *p
;
7587 * Autogroups do not have RT tasks; see autogroup_create().
7589 if (task_group_is_autogroup(tg
))
7592 for_each_process_thread(g
, p
) {
7593 if (rt_task(p
) && task_group(p
) == tg
)
7600 struct rt_schedulable_data
{
7601 struct task_group
*tg
;
7606 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7608 struct rt_schedulable_data
*d
= data
;
7609 struct task_group
*child
;
7610 unsigned long total
, sum
= 0;
7611 u64 period
, runtime
;
7613 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7614 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7617 period
= d
->rt_period
;
7618 runtime
= d
->rt_runtime
;
7622 * Cannot have more runtime than the period.
7624 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7628 * Ensure we don't starve existing RT tasks.
7630 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7633 total
= to_ratio(period
, runtime
);
7636 * Nobody can have more than the global setting allows.
7638 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7642 * The sum of our children's runtime should not exceed our own.
7644 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7645 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7646 runtime
= child
->rt_bandwidth
.rt_runtime
;
7648 if (child
== d
->tg
) {
7649 period
= d
->rt_period
;
7650 runtime
= d
->rt_runtime
;
7653 sum
+= to_ratio(period
, runtime
);
7662 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7666 struct rt_schedulable_data data
= {
7668 .rt_period
= period
,
7669 .rt_runtime
= runtime
,
7673 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7679 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7680 u64 rt_period
, u64 rt_runtime
)
7685 * Disallowing the root group RT runtime is BAD, it would disallow the
7686 * kernel creating (and or operating) RT threads.
7688 if (tg
== &root_task_group
&& rt_runtime
== 0)
7691 /* No period doesn't make any sense. */
7695 mutex_lock(&rt_constraints_mutex
);
7696 read_lock(&tasklist_lock
);
7697 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7701 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7702 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7703 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7705 for_each_possible_cpu(i
) {
7706 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7708 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7709 rt_rq
->rt_runtime
= rt_runtime
;
7710 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7712 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7714 read_unlock(&tasklist_lock
);
7715 mutex_unlock(&rt_constraints_mutex
);
7720 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7722 u64 rt_runtime
, rt_period
;
7724 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7725 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7726 if (rt_runtime_us
< 0)
7727 rt_runtime
= RUNTIME_INF
;
7729 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7732 static long sched_group_rt_runtime(struct task_group
*tg
)
7736 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7739 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7740 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7741 return rt_runtime_us
;
7744 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7746 u64 rt_runtime
, rt_period
;
7748 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7749 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7751 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7754 static long sched_group_rt_period(struct task_group
*tg
)
7758 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7759 do_div(rt_period_us
, NSEC_PER_USEC
);
7760 return rt_period_us
;
7762 #endif /* CONFIG_RT_GROUP_SCHED */
7764 #ifdef CONFIG_RT_GROUP_SCHED
7765 static int sched_rt_global_constraints(void)
7769 mutex_lock(&rt_constraints_mutex
);
7770 read_lock(&tasklist_lock
);
7771 ret
= __rt_schedulable(NULL
, 0, 0);
7772 read_unlock(&tasklist_lock
);
7773 mutex_unlock(&rt_constraints_mutex
);
7778 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7780 /* Don't accept realtime tasks when there is no way for them to run */
7781 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7787 #else /* !CONFIG_RT_GROUP_SCHED */
7788 static int sched_rt_global_constraints(void)
7790 unsigned long flags
;
7793 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7794 for_each_possible_cpu(i
) {
7795 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7797 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7798 rt_rq
->rt_runtime
= global_rt_runtime();
7799 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7801 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7805 #endif /* CONFIG_RT_GROUP_SCHED */
7807 static int sched_dl_global_validate(void)
7809 u64 runtime
= global_rt_runtime();
7810 u64 period
= global_rt_period();
7811 u64 new_bw
= to_ratio(period
, runtime
);
7814 unsigned long flags
;
7817 * Here we want to check the bandwidth not being set to some
7818 * value smaller than the currently allocated bandwidth in
7819 * any of the root_domains.
7821 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7822 * cycling on root_domains... Discussion on different/better
7823 * solutions is welcome!
7825 for_each_possible_cpu(cpu
) {
7826 rcu_read_lock_sched();
7827 dl_b
= dl_bw_of(cpu
);
7829 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7830 if (new_bw
< dl_b
->total_bw
)
7832 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7834 rcu_read_unlock_sched();
7843 static void sched_dl_do_global(void)
7848 unsigned long flags
;
7850 def_dl_bandwidth
.dl_period
= global_rt_period();
7851 def_dl_bandwidth
.dl_runtime
= global_rt_runtime();
7853 if (global_rt_runtime() != RUNTIME_INF
)
7854 new_bw
= to_ratio(global_rt_period(), global_rt_runtime());
7857 * FIXME: As above...
7859 for_each_possible_cpu(cpu
) {
7860 rcu_read_lock_sched();
7861 dl_b
= dl_bw_of(cpu
);
7863 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7865 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7867 rcu_read_unlock_sched();
7871 static int sched_rt_global_validate(void)
7873 if (sysctl_sched_rt_period
<= 0)
7876 if ((sysctl_sched_rt_runtime
!= RUNTIME_INF
) &&
7877 (sysctl_sched_rt_runtime
> sysctl_sched_rt_period
))
7883 static void sched_rt_do_global(void)
7885 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7886 def_rt_bandwidth
.rt_period
= ns_to_ktime(global_rt_period());
7889 int sched_rt_handler(struct ctl_table
*table
, int write
,
7890 void __user
*buffer
, size_t *lenp
,
7893 int old_period
, old_runtime
;
7894 static DEFINE_MUTEX(mutex
);
7898 old_period
= sysctl_sched_rt_period
;
7899 old_runtime
= sysctl_sched_rt_runtime
;
7901 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7903 if (!ret
&& write
) {
7904 ret
= sched_rt_global_validate();
7908 ret
= sched_dl_global_validate();
7912 ret
= sched_rt_global_constraints();
7916 sched_rt_do_global();
7917 sched_dl_do_global();
7921 sysctl_sched_rt_period
= old_period
;
7922 sysctl_sched_rt_runtime
= old_runtime
;
7924 mutex_unlock(&mutex
);
7929 int sched_rr_handler(struct ctl_table
*table
, int write
,
7930 void __user
*buffer
, size_t *lenp
,
7934 static DEFINE_MUTEX(mutex
);
7937 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7938 /* make sure that internally we keep jiffies */
7939 /* also, writing zero resets timeslice to default */
7940 if (!ret
&& write
) {
7941 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7942 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7944 mutex_unlock(&mutex
);
7948 #ifdef CONFIG_CGROUP_SCHED
7950 static inline struct task_group
*css_tg(struct cgroup_subsys_state
*css
)
7952 return css
? container_of(css
, struct task_group
, css
) : NULL
;
7955 static struct cgroup_subsys_state
*
7956 cpu_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
7958 struct task_group
*parent
= css_tg(parent_css
);
7959 struct task_group
*tg
;
7962 /* This is early initialization for the top cgroup */
7963 return &root_task_group
.css
;
7966 tg
= sched_create_group(parent
);
7968 return ERR_PTR(-ENOMEM
);
7973 static int cpu_cgroup_css_online(struct cgroup_subsys_state
*css
)
7975 struct task_group
*tg
= css_tg(css
);
7976 struct task_group
*parent
= css_tg(css
->parent
);
7979 sched_online_group(tg
, parent
);
7983 static void cpu_cgroup_css_free(struct cgroup_subsys_state
*css
)
7985 struct task_group
*tg
= css_tg(css
);
7987 sched_destroy_group(tg
);
7990 static void cpu_cgroup_css_offline(struct cgroup_subsys_state
*css
)
7992 struct task_group
*tg
= css_tg(css
);
7994 sched_offline_group(tg
);
7997 static void cpu_cgroup_fork(struct task_struct
*task
)
7999 sched_move_task(task
);
8002 static int cpu_cgroup_can_attach(struct cgroup_subsys_state
*css
,
8003 struct cgroup_taskset
*tset
)
8005 struct task_struct
*task
;
8007 cgroup_taskset_for_each(task
, tset
) {
8008 #ifdef CONFIG_RT_GROUP_SCHED
8009 if (!sched_rt_can_attach(css_tg(css
), task
))
8012 /* We don't support RT-tasks being in separate groups */
8013 if (task
->sched_class
!= &fair_sched_class
)
8020 static void cpu_cgroup_attach(struct cgroup_subsys_state
*css
,
8021 struct cgroup_taskset
*tset
)
8023 struct task_struct
*task
;
8025 cgroup_taskset_for_each(task
, tset
)
8026 sched_move_task(task
);
8029 static void cpu_cgroup_exit(struct cgroup_subsys_state
*css
,
8030 struct cgroup_subsys_state
*old_css
,
8031 struct task_struct
*task
)
8034 * cgroup_exit() is called in the copy_process() failure path.
8035 * Ignore this case since the task hasn't ran yet, this avoids
8036 * trying to poke a half freed task state from generic code.
8038 if (!(task
->flags
& PF_EXITING
))
8041 sched_move_task(task
);
8044 #ifdef CONFIG_FAIR_GROUP_SCHED
8045 static int cpu_shares_write_u64(struct cgroup_subsys_state
*css
,
8046 struct cftype
*cftype
, u64 shareval
)
8048 return sched_group_set_shares(css_tg(css
), scale_load(shareval
));
8051 static u64
cpu_shares_read_u64(struct cgroup_subsys_state
*css
,
8054 struct task_group
*tg
= css_tg(css
);
8056 return (u64
) scale_load_down(tg
->shares
);
8059 #ifdef CONFIG_CFS_BANDWIDTH
8060 static DEFINE_MUTEX(cfs_constraints_mutex
);
8062 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
8063 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
8065 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
8067 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
8069 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
8070 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8072 if (tg
== &root_task_group
)
8076 * Ensure we have at some amount of bandwidth every period. This is
8077 * to prevent reaching a state of large arrears when throttled via
8078 * entity_tick() resulting in prolonged exit starvation.
8080 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
8084 * Likewise, bound things on the otherside by preventing insane quota
8085 * periods. This also allows us to normalize in computing quota
8088 if (period
> max_cfs_quota_period
)
8092 * Prevent race between setting of cfs_rq->runtime_enabled and
8093 * unthrottle_offline_cfs_rqs().
8096 mutex_lock(&cfs_constraints_mutex
);
8097 ret
= __cfs_schedulable(tg
, period
, quota
);
8101 runtime_enabled
= quota
!= RUNTIME_INF
;
8102 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
8104 * If we need to toggle cfs_bandwidth_used, off->on must occur
8105 * before making related changes, and on->off must occur afterwards
8107 if (runtime_enabled
&& !runtime_was_enabled
)
8108 cfs_bandwidth_usage_inc();
8109 raw_spin_lock_irq(&cfs_b
->lock
);
8110 cfs_b
->period
= ns_to_ktime(period
);
8111 cfs_b
->quota
= quota
;
8113 __refill_cfs_bandwidth_runtime(cfs_b
);
8114 /* restart the period timer (if active) to handle new period expiry */
8115 if (runtime_enabled
&& cfs_b
->timer_active
) {
8116 /* force a reprogram */
8117 __start_cfs_bandwidth(cfs_b
, true);
8119 raw_spin_unlock_irq(&cfs_b
->lock
);
8121 for_each_online_cpu(i
) {
8122 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
8123 struct rq
*rq
= cfs_rq
->rq
;
8125 raw_spin_lock_irq(&rq
->lock
);
8126 cfs_rq
->runtime_enabled
= runtime_enabled
;
8127 cfs_rq
->runtime_remaining
= 0;
8129 if (cfs_rq
->throttled
)
8130 unthrottle_cfs_rq(cfs_rq
);
8131 raw_spin_unlock_irq(&rq
->lock
);
8133 if (runtime_was_enabled
&& !runtime_enabled
)
8134 cfs_bandwidth_usage_dec();
8136 mutex_unlock(&cfs_constraints_mutex
);
8142 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
8146 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
8147 if (cfs_quota_us
< 0)
8148 quota
= RUNTIME_INF
;
8150 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
8152 return tg_set_cfs_bandwidth(tg
, period
, quota
);
8155 long tg_get_cfs_quota(struct task_group
*tg
)
8159 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
8162 quota_us
= tg
->cfs_bandwidth
.quota
;
8163 do_div(quota_us
, NSEC_PER_USEC
);
8168 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
8172 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
8173 quota
= tg
->cfs_bandwidth
.quota
;
8175 return tg_set_cfs_bandwidth(tg
, period
, quota
);
8178 long tg_get_cfs_period(struct task_group
*tg
)
8182 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
8183 do_div(cfs_period_us
, NSEC_PER_USEC
);
8185 return cfs_period_us
;
8188 static s64
cpu_cfs_quota_read_s64(struct cgroup_subsys_state
*css
,
8191 return tg_get_cfs_quota(css_tg(css
));
8194 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state
*css
,
8195 struct cftype
*cftype
, s64 cfs_quota_us
)
8197 return tg_set_cfs_quota(css_tg(css
), cfs_quota_us
);
8200 static u64
cpu_cfs_period_read_u64(struct cgroup_subsys_state
*css
,
8203 return tg_get_cfs_period(css_tg(css
));
8206 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state
*css
,
8207 struct cftype
*cftype
, u64 cfs_period_us
)
8209 return tg_set_cfs_period(css_tg(css
), cfs_period_us
);
8212 struct cfs_schedulable_data
{
8213 struct task_group
*tg
;
8218 * normalize group quota/period to be quota/max_period
8219 * note: units are usecs
8221 static u64
normalize_cfs_quota(struct task_group
*tg
,
8222 struct cfs_schedulable_data
*d
)
8230 period
= tg_get_cfs_period(tg
);
8231 quota
= tg_get_cfs_quota(tg
);
8234 /* note: these should typically be equivalent */
8235 if (quota
== RUNTIME_INF
|| quota
== -1)
8238 return to_ratio(period
, quota
);
8241 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
8243 struct cfs_schedulable_data
*d
= data
;
8244 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8245 s64 quota
= 0, parent_quota
= -1;
8248 quota
= RUNTIME_INF
;
8250 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
8252 quota
= normalize_cfs_quota(tg
, d
);
8253 parent_quota
= parent_b
->hierarchical_quota
;
8256 * ensure max(child_quota) <= parent_quota, inherit when no
8259 if (quota
== RUNTIME_INF
)
8260 quota
= parent_quota
;
8261 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
8264 cfs_b
->hierarchical_quota
= quota
;
8269 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
8272 struct cfs_schedulable_data data
= {
8278 if (quota
!= RUNTIME_INF
) {
8279 do_div(data
.period
, NSEC_PER_USEC
);
8280 do_div(data
.quota
, NSEC_PER_USEC
);
8284 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
8290 static int cpu_stats_show(struct seq_file
*sf
, void *v
)
8292 struct task_group
*tg
= css_tg(seq_css(sf
));
8293 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8295 seq_printf(sf
, "nr_periods %d\n", cfs_b
->nr_periods
);
8296 seq_printf(sf
, "nr_throttled %d\n", cfs_b
->nr_throttled
);
8297 seq_printf(sf
, "throttled_time %llu\n", cfs_b
->throttled_time
);
8301 #endif /* CONFIG_CFS_BANDWIDTH */
8302 #endif /* CONFIG_FAIR_GROUP_SCHED */
8304 #ifdef CONFIG_RT_GROUP_SCHED
8305 static int cpu_rt_runtime_write(struct cgroup_subsys_state
*css
,
8306 struct cftype
*cft
, s64 val
)
8308 return sched_group_set_rt_runtime(css_tg(css
), val
);
8311 static s64
cpu_rt_runtime_read(struct cgroup_subsys_state
*css
,
8314 return sched_group_rt_runtime(css_tg(css
));
8317 static int cpu_rt_period_write_uint(struct cgroup_subsys_state
*css
,
8318 struct cftype
*cftype
, u64 rt_period_us
)
8320 return sched_group_set_rt_period(css_tg(css
), rt_period_us
);
8323 static u64
cpu_rt_period_read_uint(struct cgroup_subsys_state
*css
,
8326 return sched_group_rt_period(css_tg(css
));
8328 #endif /* CONFIG_RT_GROUP_SCHED */
8330 static struct cftype cpu_files
[] = {
8331 #ifdef CONFIG_FAIR_GROUP_SCHED
8334 .read_u64
= cpu_shares_read_u64
,
8335 .write_u64
= cpu_shares_write_u64
,
8338 #ifdef CONFIG_CFS_BANDWIDTH
8340 .name
= "cfs_quota_us",
8341 .read_s64
= cpu_cfs_quota_read_s64
,
8342 .write_s64
= cpu_cfs_quota_write_s64
,
8345 .name
= "cfs_period_us",
8346 .read_u64
= cpu_cfs_period_read_u64
,
8347 .write_u64
= cpu_cfs_period_write_u64
,
8351 .seq_show
= cpu_stats_show
,
8354 #ifdef CONFIG_RT_GROUP_SCHED
8356 .name
= "rt_runtime_us",
8357 .read_s64
= cpu_rt_runtime_read
,
8358 .write_s64
= cpu_rt_runtime_write
,
8361 .name
= "rt_period_us",
8362 .read_u64
= cpu_rt_period_read_uint
,
8363 .write_u64
= cpu_rt_period_write_uint
,
8369 struct cgroup_subsys cpu_cgrp_subsys
= {
8370 .css_alloc
= cpu_cgroup_css_alloc
,
8371 .css_free
= cpu_cgroup_css_free
,
8372 .css_online
= cpu_cgroup_css_online
,
8373 .css_offline
= cpu_cgroup_css_offline
,
8374 .fork
= cpu_cgroup_fork
,
8375 .can_attach
= cpu_cgroup_can_attach
,
8376 .attach
= cpu_cgroup_attach
,
8377 .exit
= cpu_cgroup_exit
,
8378 .legacy_cftypes
= cpu_files
,
8382 #endif /* CONFIG_CGROUP_SCHED */
8384 void dump_cpu_task(int cpu
)
8386 pr_info("Task dump for CPU %d:\n", cpu
);
8387 sched_show_task(cpu_curr(cpu
));