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;
309 /* cpus with isolated domains */
310 cpumask_var_t cpu_isolated_map
;
313 * this_rq_lock - lock this runqueue and disable interrupts.
315 static struct rq
*this_rq_lock(void)
322 raw_spin_lock(&rq
->lock
);
327 #ifdef CONFIG_SCHED_HRTICK
329 * Use HR-timers to deliver accurate preemption points.
332 static void hrtick_clear(struct rq
*rq
)
334 if (hrtimer_active(&rq
->hrtick_timer
))
335 hrtimer_cancel(&rq
->hrtick_timer
);
339 * High-resolution timer tick.
340 * Runs from hardirq context with interrupts disabled.
342 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
344 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
346 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
348 raw_spin_lock(&rq
->lock
);
350 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
351 raw_spin_unlock(&rq
->lock
);
353 return HRTIMER_NORESTART
;
358 static int __hrtick_restart(struct rq
*rq
)
360 struct hrtimer
*timer
= &rq
->hrtick_timer
;
361 ktime_t time
= hrtimer_get_softexpires(timer
);
363 return __hrtimer_start_range_ns(timer
, time
, 0, HRTIMER_MODE_ABS_PINNED
, 0);
367 * called from hardirq (IPI) context
369 static void __hrtick_start(void *arg
)
373 raw_spin_lock(&rq
->lock
);
374 __hrtick_restart(rq
);
375 rq
->hrtick_csd_pending
= 0;
376 raw_spin_unlock(&rq
->lock
);
380 * Called to set the hrtick timer state.
382 * called with rq->lock held and irqs disabled
384 void hrtick_start(struct rq
*rq
, u64 delay
)
386 struct hrtimer
*timer
= &rq
->hrtick_timer
;
391 * Don't schedule slices shorter than 10000ns, that just
392 * doesn't make sense and can cause timer DoS.
394 delta
= max_t(s64
, delay
, 10000LL);
395 time
= ktime_add_ns(timer
->base
->get_time(), delta
);
397 hrtimer_set_expires(timer
, time
);
399 if (rq
== this_rq()) {
400 __hrtick_restart(rq
);
401 } else if (!rq
->hrtick_csd_pending
) {
402 smp_call_function_single_async(cpu_of(rq
), &rq
->hrtick_csd
);
403 rq
->hrtick_csd_pending
= 1;
408 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
410 int cpu
= (int)(long)hcpu
;
413 case CPU_UP_CANCELED
:
414 case CPU_UP_CANCELED_FROZEN
:
415 case CPU_DOWN_PREPARE
:
416 case CPU_DOWN_PREPARE_FROZEN
:
418 case CPU_DEAD_FROZEN
:
419 hrtick_clear(cpu_rq(cpu
));
426 static __init
void init_hrtick(void)
428 hotcpu_notifier(hotplug_hrtick
, 0);
432 * Called to set the hrtick timer state.
434 * called with rq->lock held and irqs disabled
436 void hrtick_start(struct rq
*rq
, u64 delay
)
439 * Don't schedule slices shorter than 10000ns, that just
440 * doesn't make sense. Rely on vruntime for fairness.
442 delay
= max_t(u64
, delay
, 10000LL);
443 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
444 HRTIMER_MODE_REL_PINNED
, 0);
447 static inline void init_hrtick(void)
450 #endif /* CONFIG_SMP */
452 static void init_rq_hrtick(struct rq
*rq
)
455 rq
->hrtick_csd_pending
= 0;
457 rq
->hrtick_csd
.flags
= 0;
458 rq
->hrtick_csd
.func
= __hrtick_start
;
459 rq
->hrtick_csd
.info
= rq
;
462 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
463 rq
->hrtick_timer
.function
= hrtick
;
465 #else /* CONFIG_SCHED_HRTICK */
466 static inline void hrtick_clear(struct rq
*rq
)
470 static inline void init_rq_hrtick(struct rq
*rq
)
474 static inline void init_hrtick(void)
477 #endif /* CONFIG_SCHED_HRTICK */
480 * cmpxchg based fetch_or, macro so it works for different integer types
482 #define fetch_or(ptr, val) \
483 ({ typeof(*(ptr)) __old, __val = *(ptr); \
485 __old = cmpxchg((ptr), __val, __val | (val)); \
486 if (__old == __val) \
493 #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
495 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
496 * this avoids any races wrt polling state changes and thereby avoids
499 static bool set_nr_and_not_polling(struct task_struct
*p
)
501 struct thread_info
*ti
= task_thread_info(p
);
502 return !(fetch_or(&ti
->flags
, _TIF_NEED_RESCHED
) & _TIF_POLLING_NRFLAG
);
506 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
508 * If this returns true, then the idle task promises to call
509 * sched_ttwu_pending() and reschedule soon.
511 static bool set_nr_if_polling(struct task_struct
*p
)
513 struct thread_info
*ti
= task_thread_info(p
);
514 typeof(ti
->flags
) old
, val
= ACCESS_ONCE(ti
->flags
);
517 if (!(val
& _TIF_POLLING_NRFLAG
))
519 if (val
& _TIF_NEED_RESCHED
)
521 old
= cmpxchg(&ti
->flags
, val
, val
| _TIF_NEED_RESCHED
);
530 static bool set_nr_and_not_polling(struct task_struct
*p
)
532 set_tsk_need_resched(p
);
537 static bool set_nr_if_polling(struct task_struct
*p
)
545 * resched_curr - mark rq's current task 'to be rescheduled now'.
547 * On UP this means the setting of the need_resched flag, on SMP it
548 * might also involve a cross-CPU call to trigger the scheduler on
551 void resched_curr(struct rq
*rq
)
553 struct task_struct
*curr
= rq
->curr
;
556 lockdep_assert_held(&rq
->lock
);
558 if (test_tsk_need_resched(curr
))
563 if (cpu
== smp_processor_id()) {
564 set_tsk_need_resched(curr
);
565 set_preempt_need_resched();
569 if (set_nr_and_not_polling(curr
))
570 smp_send_reschedule(cpu
);
572 trace_sched_wake_idle_without_ipi(cpu
);
575 void resched_cpu(int cpu
)
577 struct rq
*rq
= cpu_rq(cpu
);
580 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
583 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
587 #ifdef CONFIG_NO_HZ_COMMON
589 * In the semi idle case, use the nearest busy cpu for migrating timers
590 * from an idle cpu. This is good for power-savings.
592 * We don't do similar optimization for completely idle system, as
593 * selecting an idle cpu will add more delays to the timers than intended
594 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
596 int get_nohz_timer_target(int pinned
)
598 int cpu
= smp_processor_id();
600 struct sched_domain
*sd
;
602 if (pinned
|| !get_sysctl_timer_migration() || !idle_cpu(cpu
))
606 for_each_domain(cpu
, sd
) {
607 for_each_cpu(i
, sched_domain_span(sd
)) {
619 * When add_timer_on() enqueues a timer into the timer wheel of an
620 * idle CPU then this timer might expire before the next timer event
621 * which is scheduled to wake up that CPU. In case of a completely
622 * idle system the next event might even be infinite time into the
623 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
624 * leaves the inner idle loop so the newly added timer is taken into
625 * account when the CPU goes back to idle and evaluates the timer
626 * wheel for the next timer event.
628 static void wake_up_idle_cpu(int cpu
)
630 struct rq
*rq
= cpu_rq(cpu
);
632 if (cpu
== smp_processor_id())
635 if (set_nr_and_not_polling(rq
->idle
))
636 smp_send_reschedule(cpu
);
638 trace_sched_wake_idle_without_ipi(cpu
);
641 static bool wake_up_full_nohz_cpu(int cpu
)
644 * We just need the target to call irq_exit() and re-evaluate
645 * the next tick. The nohz full kick at least implies that.
646 * If needed we can still optimize that later with an
649 if (tick_nohz_full_cpu(cpu
)) {
650 if (cpu
!= smp_processor_id() ||
651 tick_nohz_tick_stopped())
652 tick_nohz_full_kick_cpu(cpu
);
659 void wake_up_nohz_cpu(int cpu
)
661 if (!wake_up_full_nohz_cpu(cpu
))
662 wake_up_idle_cpu(cpu
);
665 static inline bool got_nohz_idle_kick(void)
667 int cpu
= smp_processor_id();
669 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
672 if (idle_cpu(cpu
) && !need_resched())
676 * We can't run Idle Load Balance on this CPU for this time so we
677 * cancel it and clear NOHZ_BALANCE_KICK
679 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
683 #else /* CONFIG_NO_HZ_COMMON */
685 static inline bool got_nohz_idle_kick(void)
690 #endif /* CONFIG_NO_HZ_COMMON */
692 #ifdef CONFIG_NO_HZ_FULL
693 bool sched_can_stop_tick(void)
696 * FIFO realtime policy runs the highest priority task. Other runnable
697 * tasks are of a lower priority. The scheduler tick does nothing.
699 if (current
->policy
== SCHED_FIFO
)
703 * Round-robin realtime tasks time slice with other tasks at the same
704 * realtime priority. Is this task the only one at this priority?
706 if (current
->policy
== SCHED_RR
) {
707 struct sched_rt_entity
*rt_se
= ¤t
->rt
;
709 return rt_se
->run_list
.prev
== rt_se
->run_list
.next
;
713 * More than one running task need preemption.
714 * nr_running update is assumed to be visible
715 * after IPI is sent from wakers.
717 if (this_rq()->nr_running
> 1)
722 #endif /* CONFIG_NO_HZ_FULL */
724 void sched_avg_update(struct rq
*rq
)
726 s64 period
= sched_avg_period();
728 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
730 * Inline assembly required to prevent the compiler
731 * optimising this loop into a divmod call.
732 * See __iter_div_u64_rem() for another example of this.
734 asm("" : "+rm" (rq
->age_stamp
));
735 rq
->age_stamp
+= period
;
740 #endif /* CONFIG_SMP */
742 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
743 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
745 * Iterate task_group tree rooted at *from, calling @down when first entering a
746 * node and @up when leaving it for the final time.
748 * Caller must hold rcu_lock or sufficient equivalent.
750 int walk_tg_tree_from(struct task_group
*from
,
751 tg_visitor down
, tg_visitor up
, void *data
)
753 struct task_group
*parent
, *child
;
759 ret
= (*down
)(parent
, data
);
762 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
769 ret
= (*up
)(parent
, data
);
770 if (ret
|| parent
== from
)
774 parent
= parent
->parent
;
781 int tg_nop(struct task_group
*tg
, void *data
)
787 static void set_load_weight(struct task_struct
*p
)
789 int prio
= p
->static_prio
- MAX_RT_PRIO
;
790 struct load_weight
*load
= &p
->se
.load
;
793 * SCHED_IDLE tasks get minimal weight:
795 if (p
->policy
== SCHED_IDLE
) {
796 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
797 load
->inv_weight
= WMULT_IDLEPRIO
;
801 load
->weight
= scale_load(prio_to_weight
[prio
]);
802 load
->inv_weight
= prio_to_wmult
[prio
];
805 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
808 sched_info_queued(rq
, p
);
809 p
->sched_class
->enqueue_task(rq
, p
, flags
);
812 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
815 sched_info_dequeued(rq
, p
);
816 p
->sched_class
->dequeue_task(rq
, p
, flags
);
819 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
821 if (task_contributes_to_load(p
))
822 rq
->nr_uninterruptible
--;
824 enqueue_task(rq
, p
, flags
);
827 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
829 if (task_contributes_to_load(p
))
830 rq
->nr_uninterruptible
++;
832 dequeue_task(rq
, p
, flags
);
835 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
838 * In theory, the compile should just see 0 here, and optimize out the call
839 * to sched_rt_avg_update. But I don't trust it...
841 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
842 s64 steal
= 0, irq_delta
= 0;
844 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
845 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
848 * Since irq_time is only updated on {soft,}irq_exit, we might run into
849 * this case when a previous update_rq_clock() happened inside a
852 * When this happens, we stop ->clock_task and only update the
853 * prev_irq_time stamp to account for the part that fit, so that a next
854 * update will consume the rest. This ensures ->clock_task is
857 * It does however cause some slight miss-attribution of {soft,}irq
858 * time, a more accurate solution would be to update the irq_time using
859 * the current rq->clock timestamp, except that would require using
862 if (irq_delta
> delta
)
865 rq
->prev_irq_time
+= irq_delta
;
868 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
869 if (static_key_false((¶virt_steal_rq_enabled
))) {
870 steal
= paravirt_steal_clock(cpu_of(rq
));
871 steal
-= rq
->prev_steal_time_rq
;
873 if (unlikely(steal
> delta
))
876 rq
->prev_steal_time_rq
+= steal
;
881 rq
->clock_task
+= delta
;
883 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
884 if ((irq_delta
+ steal
) && sched_feat(NONTASK_CAPACITY
))
885 sched_rt_avg_update(rq
, irq_delta
+ steal
);
889 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
891 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
892 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
896 * Make it appear like a SCHED_FIFO task, its something
897 * userspace knows about and won't get confused about.
899 * Also, it will make PI more or less work without too
900 * much confusion -- but then, stop work should not
901 * rely on PI working anyway.
903 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
905 stop
->sched_class
= &stop_sched_class
;
908 cpu_rq(cpu
)->stop
= stop
;
912 * Reset it back to a normal scheduling class so that
913 * it can die in pieces.
915 old_stop
->sched_class
= &rt_sched_class
;
920 * __normal_prio - return the priority that is based on the static prio
922 static inline int __normal_prio(struct task_struct
*p
)
924 return p
->static_prio
;
928 * Calculate the expected normal priority: i.e. priority
929 * without taking RT-inheritance into account. Might be
930 * boosted by interactivity modifiers. Changes upon fork,
931 * setprio syscalls, and whenever the interactivity
932 * estimator recalculates.
934 static inline int normal_prio(struct task_struct
*p
)
938 if (task_has_dl_policy(p
))
939 prio
= MAX_DL_PRIO
-1;
940 else if (task_has_rt_policy(p
))
941 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
943 prio
= __normal_prio(p
);
948 * Calculate the current priority, i.e. the priority
949 * taken into account by the scheduler. This value might
950 * be boosted by RT tasks, or might be boosted by
951 * interactivity modifiers. Will be RT if the task got
952 * RT-boosted. If not then it returns p->normal_prio.
954 static int effective_prio(struct task_struct
*p
)
956 p
->normal_prio
= normal_prio(p
);
958 * If we are RT tasks or we were boosted to RT priority,
959 * keep the priority unchanged. Otherwise, update priority
960 * to the normal priority:
962 if (!rt_prio(p
->prio
))
963 return p
->normal_prio
;
968 * task_curr - is this task currently executing on a CPU?
969 * @p: the task in question.
971 * Return: 1 if the task is currently executing. 0 otherwise.
973 inline int task_curr(const struct task_struct
*p
)
975 return cpu_curr(task_cpu(p
)) == p
;
979 * Can drop rq->lock because from sched_class::switched_from() methods drop it.
981 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
982 const struct sched_class
*prev_class
,
985 if (prev_class
!= p
->sched_class
) {
986 if (prev_class
->switched_from
)
987 prev_class
->switched_from(rq
, p
);
988 /* Possble rq->lock 'hole'. */
989 p
->sched_class
->switched_to(rq
, p
);
990 } else if (oldprio
!= p
->prio
|| dl_task(p
))
991 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
994 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
996 const struct sched_class
*class;
998 if (p
->sched_class
== rq
->curr
->sched_class
) {
999 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
1001 for_each_class(class) {
1002 if (class == rq
->curr
->sched_class
)
1004 if (class == p
->sched_class
) {
1012 * A queue event has occurred, and we're going to schedule. In
1013 * this case, we can save a useless back to back clock update.
1015 if (task_on_rq_queued(rq
->curr
) && test_tsk_need_resched(rq
->curr
))
1016 rq_clock_skip_update(rq
, true);
1020 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1022 #ifdef CONFIG_SCHED_DEBUG
1024 * We should never call set_task_cpu() on a blocked task,
1025 * ttwu() will sort out the placement.
1027 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
1030 #ifdef CONFIG_LOCKDEP
1032 * The caller should hold either p->pi_lock or rq->lock, when changing
1033 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1035 * sched_move_task() holds both and thus holding either pins the cgroup,
1038 * Furthermore, all task_rq users should acquire both locks, see
1041 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1042 lockdep_is_held(&task_rq(p
)->lock
)));
1046 trace_sched_migrate_task(p
, new_cpu
);
1048 if (task_cpu(p
) != new_cpu
) {
1049 if (p
->sched_class
->migrate_task_rq
)
1050 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1051 p
->se
.nr_migrations
++;
1052 perf_sw_event_sched(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, 0);
1055 __set_task_cpu(p
, new_cpu
);
1058 static void __migrate_swap_task(struct task_struct
*p
, int cpu
)
1060 if (task_on_rq_queued(p
)) {
1061 struct rq
*src_rq
, *dst_rq
;
1063 src_rq
= task_rq(p
);
1064 dst_rq
= cpu_rq(cpu
);
1066 deactivate_task(src_rq
, p
, 0);
1067 set_task_cpu(p
, cpu
);
1068 activate_task(dst_rq
, p
, 0);
1069 check_preempt_curr(dst_rq
, p
, 0);
1072 * Task isn't running anymore; make it appear like we migrated
1073 * it before it went to sleep. This means on wakeup we make the
1074 * previous cpu our targer instead of where it really is.
1080 struct migration_swap_arg
{
1081 struct task_struct
*src_task
, *dst_task
;
1082 int src_cpu
, dst_cpu
;
1085 static int migrate_swap_stop(void *data
)
1087 struct migration_swap_arg
*arg
= data
;
1088 struct rq
*src_rq
, *dst_rq
;
1091 src_rq
= cpu_rq(arg
->src_cpu
);
1092 dst_rq
= cpu_rq(arg
->dst_cpu
);
1094 double_raw_lock(&arg
->src_task
->pi_lock
,
1095 &arg
->dst_task
->pi_lock
);
1096 double_rq_lock(src_rq
, dst_rq
);
1097 if (task_cpu(arg
->dst_task
) != arg
->dst_cpu
)
1100 if (task_cpu(arg
->src_task
) != arg
->src_cpu
)
1103 if (!cpumask_test_cpu(arg
->dst_cpu
, tsk_cpus_allowed(arg
->src_task
)))
1106 if (!cpumask_test_cpu(arg
->src_cpu
, tsk_cpus_allowed(arg
->dst_task
)))
1109 __migrate_swap_task(arg
->src_task
, arg
->dst_cpu
);
1110 __migrate_swap_task(arg
->dst_task
, arg
->src_cpu
);
1115 double_rq_unlock(src_rq
, dst_rq
);
1116 raw_spin_unlock(&arg
->dst_task
->pi_lock
);
1117 raw_spin_unlock(&arg
->src_task
->pi_lock
);
1123 * Cross migrate two tasks
1125 int migrate_swap(struct task_struct
*cur
, struct task_struct
*p
)
1127 struct migration_swap_arg arg
;
1130 arg
= (struct migration_swap_arg
){
1132 .src_cpu
= task_cpu(cur
),
1134 .dst_cpu
= task_cpu(p
),
1137 if (arg
.src_cpu
== arg
.dst_cpu
)
1141 * These three tests are all lockless; this is OK since all of them
1142 * will be re-checked with proper locks held further down the line.
1144 if (!cpu_active(arg
.src_cpu
) || !cpu_active(arg
.dst_cpu
))
1147 if (!cpumask_test_cpu(arg
.dst_cpu
, tsk_cpus_allowed(arg
.src_task
)))
1150 if (!cpumask_test_cpu(arg
.src_cpu
, tsk_cpus_allowed(arg
.dst_task
)))
1153 trace_sched_swap_numa(cur
, arg
.src_cpu
, p
, arg
.dst_cpu
);
1154 ret
= stop_two_cpus(arg
.dst_cpu
, arg
.src_cpu
, migrate_swap_stop
, &arg
);
1160 struct migration_arg
{
1161 struct task_struct
*task
;
1165 static int migration_cpu_stop(void *data
);
1168 * wait_task_inactive - wait for a thread to unschedule.
1170 * If @match_state is nonzero, it's the @p->state value just checked and
1171 * not expected to change. If it changes, i.e. @p might have woken up,
1172 * then return zero. When we succeed in waiting for @p to be off its CPU,
1173 * we return a positive number (its total switch count). If a second call
1174 * a short while later returns the same number, the caller can be sure that
1175 * @p has remained unscheduled the whole time.
1177 * The caller must ensure that the task *will* unschedule sometime soon,
1178 * else this function might spin for a *long* time. This function can't
1179 * be called with interrupts off, or it may introduce deadlock with
1180 * smp_call_function() if an IPI is sent by the same process we are
1181 * waiting to become inactive.
1183 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1185 unsigned long flags
;
1186 int running
, queued
;
1192 * We do the initial early heuristics without holding
1193 * any task-queue locks at all. We'll only try to get
1194 * the runqueue lock when things look like they will
1200 * If the task is actively running on another CPU
1201 * still, just relax and busy-wait without holding
1204 * NOTE! Since we don't hold any locks, it's not
1205 * even sure that "rq" stays as the right runqueue!
1206 * But we don't care, since "task_running()" will
1207 * return false if the runqueue has changed and p
1208 * is actually now running somewhere else!
1210 while (task_running(rq
, p
)) {
1211 if (match_state
&& unlikely(p
->state
!= match_state
))
1217 * Ok, time to look more closely! We need the rq
1218 * lock now, to be *sure*. If we're wrong, we'll
1219 * just go back and repeat.
1221 rq
= task_rq_lock(p
, &flags
);
1222 trace_sched_wait_task(p
);
1223 running
= task_running(rq
, p
);
1224 queued
= task_on_rq_queued(p
);
1226 if (!match_state
|| p
->state
== match_state
)
1227 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1228 task_rq_unlock(rq
, p
, &flags
);
1231 * If it changed from the expected state, bail out now.
1233 if (unlikely(!ncsw
))
1237 * Was it really running after all now that we
1238 * checked with the proper locks actually held?
1240 * Oops. Go back and try again..
1242 if (unlikely(running
)) {
1248 * It's not enough that it's not actively running,
1249 * it must be off the runqueue _entirely_, and not
1252 * So if it was still runnable (but just not actively
1253 * running right now), it's preempted, and we should
1254 * yield - it could be a while.
1256 if (unlikely(queued
)) {
1257 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1259 set_current_state(TASK_UNINTERRUPTIBLE
);
1260 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1265 * Ahh, all good. It wasn't running, and it wasn't
1266 * runnable, which means that it will never become
1267 * running in the future either. We're all done!
1276 * kick_process - kick a running thread to enter/exit the kernel
1277 * @p: the to-be-kicked thread
1279 * Cause a process which is running on another CPU to enter
1280 * kernel-mode, without any delay. (to get signals handled.)
1282 * NOTE: this function doesn't have to take the runqueue lock,
1283 * because all it wants to ensure is that the remote task enters
1284 * the kernel. If the IPI races and the task has been migrated
1285 * to another CPU then no harm is done and the purpose has been
1288 void kick_process(struct task_struct
*p
)
1294 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1295 smp_send_reschedule(cpu
);
1298 EXPORT_SYMBOL_GPL(kick_process
);
1299 #endif /* CONFIG_SMP */
1303 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1305 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1307 int nid
= cpu_to_node(cpu
);
1308 const struct cpumask
*nodemask
= NULL
;
1309 enum { cpuset
, possible
, fail
} state
= cpuset
;
1313 * If the node that the cpu is on has been offlined, cpu_to_node()
1314 * will return -1. There is no cpu on the node, and we should
1315 * select the cpu on the other node.
1318 nodemask
= cpumask_of_node(nid
);
1320 /* Look for allowed, online CPU in same node. */
1321 for_each_cpu(dest_cpu
, nodemask
) {
1322 if (!cpu_online(dest_cpu
))
1324 if (!cpu_active(dest_cpu
))
1326 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1332 /* Any allowed, online CPU? */
1333 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1334 if (!cpu_online(dest_cpu
))
1336 if (!cpu_active(dest_cpu
))
1343 /* No more Mr. Nice Guy. */
1344 cpuset_cpus_allowed_fallback(p
);
1349 do_set_cpus_allowed(p
, cpu_possible_mask
);
1360 if (state
!= cpuset
) {
1362 * Don't tell them about moving exiting tasks or
1363 * kernel threads (both mm NULL), since they never
1366 if (p
->mm
&& printk_ratelimit()) {
1367 printk_deferred("process %d (%s) no longer affine to cpu%d\n",
1368 task_pid_nr(p
), p
->comm
, cpu
);
1376 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1379 int select_task_rq(struct task_struct
*p
, int cpu
, int sd_flags
, int wake_flags
)
1381 if (p
->nr_cpus_allowed
> 1)
1382 cpu
= p
->sched_class
->select_task_rq(p
, cpu
, sd_flags
, wake_flags
);
1385 * In order not to call set_task_cpu() on a blocking task we need
1386 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1389 * Since this is common to all placement strategies, this lives here.
1391 * [ this allows ->select_task() to simply return task_cpu(p) and
1392 * not worry about this generic constraint ]
1394 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1396 cpu
= select_fallback_rq(task_cpu(p
), p
);
1401 static void update_avg(u64
*avg
, u64 sample
)
1403 s64 diff
= sample
- *avg
;
1409 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1411 #ifdef CONFIG_SCHEDSTATS
1412 struct rq
*rq
= this_rq();
1415 int this_cpu
= smp_processor_id();
1417 if (cpu
== this_cpu
) {
1418 schedstat_inc(rq
, ttwu_local
);
1419 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1421 struct sched_domain
*sd
;
1423 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1425 for_each_domain(this_cpu
, sd
) {
1426 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1427 schedstat_inc(sd
, ttwu_wake_remote
);
1434 if (wake_flags
& WF_MIGRATED
)
1435 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1437 #endif /* CONFIG_SMP */
1439 schedstat_inc(rq
, ttwu_count
);
1440 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1442 if (wake_flags
& WF_SYNC
)
1443 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1445 #endif /* CONFIG_SCHEDSTATS */
1448 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1450 activate_task(rq
, p
, en_flags
);
1451 p
->on_rq
= TASK_ON_RQ_QUEUED
;
1453 /* if a worker is waking up, notify workqueue */
1454 if (p
->flags
& PF_WQ_WORKER
)
1455 wq_worker_waking_up(p
, cpu_of(rq
));
1459 * Mark the task runnable and perform wakeup-preemption.
1462 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1464 check_preempt_curr(rq
, p
, wake_flags
);
1465 trace_sched_wakeup(p
, true);
1467 p
->state
= TASK_RUNNING
;
1469 if (p
->sched_class
->task_woken
)
1470 p
->sched_class
->task_woken(rq
, p
);
1472 if (rq
->idle_stamp
) {
1473 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1474 u64 max
= 2*rq
->max_idle_balance_cost
;
1476 update_avg(&rq
->avg_idle
, delta
);
1478 if (rq
->avg_idle
> max
)
1487 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1490 if (p
->sched_contributes_to_load
)
1491 rq
->nr_uninterruptible
--;
1494 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1495 ttwu_do_wakeup(rq
, p
, wake_flags
);
1499 * Called in case the task @p isn't fully descheduled from its runqueue,
1500 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1501 * since all we need to do is flip p->state to TASK_RUNNING, since
1502 * the task is still ->on_rq.
1504 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1509 rq
= __task_rq_lock(p
);
1510 if (task_on_rq_queued(p
)) {
1511 /* check_preempt_curr() may use rq clock */
1512 update_rq_clock(rq
);
1513 ttwu_do_wakeup(rq
, p
, wake_flags
);
1516 __task_rq_unlock(rq
);
1522 void sched_ttwu_pending(void)
1524 struct rq
*rq
= this_rq();
1525 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1526 struct task_struct
*p
;
1527 unsigned long flags
;
1532 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1535 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1536 llist
= llist_next(llist
);
1537 ttwu_do_activate(rq
, p
, 0);
1540 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1543 void scheduler_ipi(void)
1546 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1547 * TIF_NEED_RESCHED remotely (for the first time) will also send
1550 preempt_fold_need_resched();
1552 if (llist_empty(&this_rq()->wake_list
) && !got_nohz_idle_kick())
1556 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1557 * traditionally all their work was done from the interrupt return
1558 * path. Now that we actually do some work, we need to make sure
1561 * Some archs already do call them, luckily irq_enter/exit nest
1564 * Arguably we should visit all archs and update all handlers,
1565 * however a fair share of IPIs are still resched only so this would
1566 * somewhat pessimize the simple resched case.
1569 sched_ttwu_pending();
1572 * Check if someone kicked us for doing the nohz idle load balance.
1574 if (unlikely(got_nohz_idle_kick())) {
1575 this_rq()->idle_balance
= 1;
1576 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1581 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1583 struct rq
*rq
= cpu_rq(cpu
);
1585 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
)) {
1586 if (!set_nr_if_polling(rq
->idle
))
1587 smp_send_reschedule(cpu
);
1589 trace_sched_wake_idle_without_ipi(cpu
);
1593 void wake_up_if_idle(int cpu
)
1595 struct rq
*rq
= cpu_rq(cpu
);
1596 unsigned long flags
;
1600 if (!is_idle_task(rcu_dereference(rq
->curr
)))
1603 if (set_nr_if_polling(rq
->idle
)) {
1604 trace_sched_wake_idle_without_ipi(cpu
);
1606 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1607 if (is_idle_task(rq
->curr
))
1608 smp_send_reschedule(cpu
);
1609 /* Else cpu is not in idle, do nothing here */
1610 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1617 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1619 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1621 #endif /* CONFIG_SMP */
1623 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1625 struct rq
*rq
= cpu_rq(cpu
);
1627 #if defined(CONFIG_SMP)
1628 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1629 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1630 ttwu_queue_remote(p
, cpu
);
1635 raw_spin_lock(&rq
->lock
);
1636 ttwu_do_activate(rq
, p
, 0);
1637 raw_spin_unlock(&rq
->lock
);
1641 * try_to_wake_up - wake up a thread
1642 * @p: the thread to be awakened
1643 * @state: the mask of task states that can be woken
1644 * @wake_flags: wake modifier flags (WF_*)
1646 * Put it on the run-queue if it's not already there. The "current"
1647 * thread is always on the run-queue (except when the actual
1648 * re-schedule is in progress), and as such you're allowed to do
1649 * the simpler "current->state = TASK_RUNNING" to mark yourself
1650 * runnable without the overhead of this.
1652 * Return: %true if @p was woken up, %false if it was already running.
1653 * or @state didn't match @p's state.
1656 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1658 unsigned long flags
;
1659 int cpu
, success
= 0;
1662 * If we are going to wake up a thread waiting for CONDITION we
1663 * need to ensure that CONDITION=1 done by the caller can not be
1664 * reordered with p->state check below. This pairs with mb() in
1665 * set_current_state() the waiting thread does.
1667 smp_mb__before_spinlock();
1668 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1669 if (!(p
->state
& state
))
1672 success
= 1; /* we're going to change ->state */
1675 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1680 * If the owning (remote) cpu is still in the middle of schedule() with
1681 * this task as prev, wait until its done referencing the task.
1686 * Pairs with the smp_wmb() in finish_lock_switch().
1690 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1691 p
->state
= TASK_WAKING
;
1693 if (p
->sched_class
->task_waking
)
1694 p
->sched_class
->task_waking(p
);
1696 cpu
= select_task_rq(p
, p
->wake_cpu
, SD_BALANCE_WAKE
, wake_flags
);
1697 if (task_cpu(p
) != cpu
) {
1698 wake_flags
|= WF_MIGRATED
;
1699 set_task_cpu(p
, cpu
);
1701 #endif /* CONFIG_SMP */
1705 ttwu_stat(p
, cpu
, wake_flags
);
1707 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1713 * try_to_wake_up_local - try to wake up a local task with rq lock held
1714 * @p: the thread to be awakened
1716 * Put @p on the run-queue if it's not already there. The caller must
1717 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1720 static void try_to_wake_up_local(struct task_struct
*p
)
1722 struct rq
*rq
= task_rq(p
);
1724 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1725 WARN_ON_ONCE(p
== current
))
1728 lockdep_assert_held(&rq
->lock
);
1730 if (!raw_spin_trylock(&p
->pi_lock
)) {
1731 raw_spin_unlock(&rq
->lock
);
1732 raw_spin_lock(&p
->pi_lock
);
1733 raw_spin_lock(&rq
->lock
);
1736 if (!(p
->state
& TASK_NORMAL
))
1739 if (!task_on_rq_queued(p
))
1740 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1742 ttwu_do_wakeup(rq
, p
, 0);
1743 ttwu_stat(p
, smp_processor_id(), 0);
1745 raw_spin_unlock(&p
->pi_lock
);
1749 * wake_up_process - Wake up a specific process
1750 * @p: The process to be woken up.
1752 * Attempt to wake up the nominated process and move it to the set of runnable
1755 * Return: 1 if the process was woken up, 0 if it was already running.
1757 * It may be assumed that this function implies a write memory barrier before
1758 * changing the task state if and only if any tasks are woken up.
1760 int wake_up_process(struct task_struct
*p
)
1762 WARN_ON(task_is_stopped_or_traced(p
));
1763 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1765 EXPORT_SYMBOL(wake_up_process
);
1767 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1769 return try_to_wake_up(p
, state
, 0);
1773 * This function clears the sched_dl_entity static params.
1775 void __dl_clear_params(struct task_struct
*p
)
1777 struct sched_dl_entity
*dl_se
= &p
->dl
;
1779 dl_se
->dl_runtime
= 0;
1780 dl_se
->dl_deadline
= 0;
1781 dl_se
->dl_period
= 0;
1785 dl_se
->dl_throttled
= 0;
1787 dl_se
->dl_yielded
= 0;
1791 * Perform scheduler related setup for a newly forked process p.
1792 * p is forked by current.
1794 * __sched_fork() is basic setup used by init_idle() too:
1796 static void __sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1801 p
->se
.exec_start
= 0;
1802 p
->se
.sum_exec_runtime
= 0;
1803 p
->se
.prev_sum_exec_runtime
= 0;
1804 p
->se
.nr_migrations
= 0;
1807 p
->se
.avg
.decay_count
= 0;
1809 INIT_LIST_HEAD(&p
->se
.group_node
);
1811 #ifdef CONFIG_SCHEDSTATS
1812 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1815 RB_CLEAR_NODE(&p
->dl
.rb_node
);
1816 init_dl_task_timer(&p
->dl
);
1817 __dl_clear_params(p
);
1819 INIT_LIST_HEAD(&p
->rt
.run_list
);
1821 #ifdef CONFIG_PREEMPT_NOTIFIERS
1822 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1825 #ifdef CONFIG_NUMA_BALANCING
1826 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1827 p
->mm
->numa_next_scan
= jiffies
+ msecs_to_jiffies(sysctl_numa_balancing_scan_delay
);
1828 p
->mm
->numa_scan_seq
= 0;
1831 if (clone_flags
& CLONE_VM
)
1832 p
->numa_preferred_nid
= current
->numa_preferred_nid
;
1834 p
->numa_preferred_nid
= -1;
1836 p
->node_stamp
= 0ULL;
1837 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1838 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1839 p
->numa_work
.next
= &p
->numa_work
;
1840 p
->numa_faults
= NULL
;
1841 p
->last_task_numa_placement
= 0;
1842 p
->last_sum_exec_runtime
= 0;
1844 p
->numa_group
= NULL
;
1845 #endif /* CONFIG_NUMA_BALANCING */
1848 #ifdef CONFIG_NUMA_BALANCING
1849 #ifdef CONFIG_SCHED_DEBUG
1850 void set_numabalancing_state(bool enabled
)
1853 sched_feat_set("NUMA");
1855 sched_feat_set("NO_NUMA");
1858 __read_mostly
bool numabalancing_enabled
;
1860 void set_numabalancing_state(bool enabled
)
1862 numabalancing_enabled
= enabled
;
1864 #endif /* CONFIG_SCHED_DEBUG */
1866 #ifdef CONFIG_PROC_SYSCTL
1867 int sysctl_numa_balancing(struct ctl_table
*table
, int write
,
1868 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1872 int state
= numabalancing_enabled
;
1874 if (write
&& !capable(CAP_SYS_ADMIN
))
1879 err
= proc_dointvec_minmax(&t
, write
, buffer
, lenp
, ppos
);
1883 set_numabalancing_state(state
);
1890 * fork()/clone()-time setup:
1892 int sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1894 unsigned long flags
;
1895 int cpu
= get_cpu();
1897 __sched_fork(clone_flags
, p
);
1899 * We mark the process as running here. This guarantees that
1900 * nobody will actually run it, and a signal or other external
1901 * event cannot wake it up and insert it on the runqueue either.
1903 p
->state
= TASK_RUNNING
;
1906 * Make sure we do not leak PI boosting priority to the child.
1908 p
->prio
= current
->normal_prio
;
1911 * Revert to default priority/policy on fork if requested.
1913 if (unlikely(p
->sched_reset_on_fork
)) {
1914 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
1915 p
->policy
= SCHED_NORMAL
;
1916 p
->static_prio
= NICE_TO_PRIO(0);
1918 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1919 p
->static_prio
= NICE_TO_PRIO(0);
1921 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1925 * We don't need the reset flag anymore after the fork. It has
1926 * fulfilled its duty:
1928 p
->sched_reset_on_fork
= 0;
1931 if (dl_prio(p
->prio
)) {
1934 } else if (rt_prio(p
->prio
)) {
1935 p
->sched_class
= &rt_sched_class
;
1937 p
->sched_class
= &fair_sched_class
;
1940 if (p
->sched_class
->task_fork
)
1941 p
->sched_class
->task_fork(p
);
1944 * The child is not yet in the pid-hash so no cgroup attach races,
1945 * and the cgroup is pinned to this child due to cgroup_fork()
1946 * is ran before sched_fork().
1948 * Silence PROVE_RCU.
1950 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1951 set_task_cpu(p
, cpu
);
1952 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1954 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1955 if (likely(sched_info_on()))
1956 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1958 #if defined(CONFIG_SMP)
1961 init_task_preempt_count(p
);
1963 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1964 RB_CLEAR_NODE(&p
->pushable_dl_tasks
);
1971 unsigned long to_ratio(u64 period
, u64 runtime
)
1973 if (runtime
== RUNTIME_INF
)
1977 * Doing this here saves a lot of checks in all
1978 * the calling paths, and returning zero seems
1979 * safe for them anyway.
1984 return div64_u64(runtime
<< 20, period
);
1988 inline struct dl_bw
*dl_bw_of(int i
)
1990 rcu_lockdep_assert(rcu_read_lock_sched_held(),
1991 "sched RCU must be held");
1992 return &cpu_rq(i
)->rd
->dl_bw
;
1995 static inline int dl_bw_cpus(int i
)
1997 struct root_domain
*rd
= cpu_rq(i
)->rd
;
2000 rcu_lockdep_assert(rcu_read_lock_sched_held(),
2001 "sched RCU must be held");
2002 for_each_cpu_and(i
, rd
->span
, cpu_active_mask
)
2008 inline struct dl_bw
*dl_bw_of(int i
)
2010 return &cpu_rq(i
)->dl
.dl_bw
;
2013 static inline int dl_bw_cpus(int i
)
2020 * We must be sure that accepting a new task (or allowing changing the
2021 * parameters of an existing one) is consistent with the bandwidth
2022 * constraints. If yes, this function also accordingly updates the currently
2023 * allocated bandwidth to reflect the new situation.
2025 * This function is called while holding p's rq->lock.
2027 * XXX we should delay bw change until the task's 0-lag point, see
2030 static int dl_overflow(struct task_struct
*p
, int policy
,
2031 const struct sched_attr
*attr
)
2034 struct dl_bw
*dl_b
= dl_bw_of(task_cpu(p
));
2035 u64 period
= attr
->sched_period
?: attr
->sched_deadline
;
2036 u64 runtime
= attr
->sched_runtime
;
2037 u64 new_bw
= dl_policy(policy
) ? to_ratio(period
, runtime
) : 0;
2040 if (new_bw
== p
->dl
.dl_bw
)
2044 * Either if a task, enters, leave, or stays -deadline but changes
2045 * its parameters, we may need to update accordingly the total
2046 * allocated bandwidth of the container.
2048 raw_spin_lock(&dl_b
->lock
);
2049 cpus
= dl_bw_cpus(task_cpu(p
));
2050 if (dl_policy(policy
) && !task_has_dl_policy(p
) &&
2051 !__dl_overflow(dl_b
, cpus
, 0, new_bw
)) {
2052 __dl_add(dl_b
, new_bw
);
2054 } else if (dl_policy(policy
) && task_has_dl_policy(p
) &&
2055 !__dl_overflow(dl_b
, cpus
, p
->dl
.dl_bw
, new_bw
)) {
2056 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2057 __dl_add(dl_b
, new_bw
);
2059 } else if (!dl_policy(policy
) && task_has_dl_policy(p
)) {
2060 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2063 raw_spin_unlock(&dl_b
->lock
);
2068 extern void init_dl_bw(struct dl_bw
*dl_b
);
2071 * wake_up_new_task - wake up a newly created task for the first time.
2073 * This function will do some initial scheduler statistics housekeeping
2074 * that must be done for every newly created context, then puts the task
2075 * on the runqueue and wakes it.
2077 void wake_up_new_task(struct task_struct
*p
)
2079 unsigned long flags
;
2082 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2085 * Fork balancing, do it here and not earlier because:
2086 * - cpus_allowed can change in the fork path
2087 * - any previously selected cpu might disappear through hotplug
2089 set_task_cpu(p
, select_task_rq(p
, task_cpu(p
), SD_BALANCE_FORK
, 0));
2092 /* Initialize new task's runnable average */
2093 init_task_runnable_average(p
);
2094 rq
= __task_rq_lock(p
);
2095 activate_task(rq
, p
, 0);
2096 p
->on_rq
= TASK_ON_RQ_QUEUED
;
2097 trace_sched_wakeup_new(p
, true);
2098 check_preempt_curr(rq
, p
, WF_FORK
);
2100 if (p
->sched_class
->task_woken
)
2101 p
->sched_class
->task_woken(rq
, p
);
2103 task_rq_unlock(rq
, p
, &flags
);
2106 #ifdef CONFIG_PREEMPT_NOTIFIERS
2109 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2110 * @notifier: notifier struct to register
2112 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2114 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2116 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2119 * preempt_notifier_unregister - no longer interested in preemption notifications
2120 * @notifier: notifier struct to unregister
2122 * This is safe to call from within a preemption notifier.
2124 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2126 hlist_del(¬ifier
->link
);
2128 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2130 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2132 struct preempt_notifier
*notifier
;
2134 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2135 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2139 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2140 struct task_struct
*next
)
2142 struct preempt_notifier
*notifier
;
2144 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2145 notifier
->ops
->sched_out(notifier
, next
);
2148 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2150 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2155 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2156 struct task_struct
*next
)
2160 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2163 * prepare_task_switch - prepare to switch tasks
2164 * @rq: the runqueue preparing to switch
2165 * @prev: the current task that is being switched out
2166 * @next: the task we are going to switch to.
2168 * This is called with the rq lock held and interrupts off. It must
2169 * be paired with a subsequent finish_task_switch after the context
2172 * prepare_task_switch sets up locking and calls architecture specific
2176 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2177 struct task_struct
*next
)
2179 trace_sched_switch(prev
, next
);
2180 sched_info_switch(rq
, prev
, next
);
2181 perf_event_task_sched_out(prev
, next
);
2182 fire_sched_out_preempt_notifiers(prev
, next
);
2183 prepare_lock_switch(rq
, next
);
2184 prepare_arch_switch(next
);
2188 * finish_task_switch - clean up after a task-switch
2189 * @prev: the thread we just switched away from.
2191 * finish_task_switch must be called after the context switch, paired
2192 * with a prepare_task_switch call before the context switch.
2193 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2194 * and do any other architecture-specific cleanup actions.
2196 * Note that we may have delayed dropping an mm in context_switch(). If
2197 * so, we finish that here outside of the runqueue lock. (Doing it
2198 * with the lock held can cause deadlocks; see schedule() for
2201 * The context switch have flipped the stack from under us and restored the
2202 * local variables which were saved when this task called schedule() in the
2203 * past. prev == current is still correct but we need to recalculate this_rq
2204 * because prev may have moved to another CPU.
2206 static struct rq
*finish_task_switch(struct task_struct
*prev
)
2207 __releases(rq
->lock
)
2209 struct rq
*rq
= this_rq();
2210 struct mm_struct
*mm
= rq
->prev_mm
;
2216 * A task struct has one reference for the use as "current".
2217 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2218 * schedule one last time. The schedule call will never return, and
2219 * the scheduled task must drop that reference.
2220 * The test for TASK_DEAD must occur while the runqueue locks are
2221 * still held, otherwise prev could be scheduled on another cpu, die
2222 * there before we look at prev->state, and then the reference would
2224 * Manfred Spraul <manfred@colorfullife.com>
2226 prev_state
= prev
->state
;
2227 vtime_task_switch(prev
);
2228 finish_arch_switch(prev
);
2229 perf_event_task_sched_in(prev
, current
);
2230 finish_lock_switch(rq
, prev
);
2231 finish_arch_post_lock_switch();
2233 fire_sched_in_preempt_notifiers(current
);
2236 if (unlikely(prev_state
== TASK_DEAD
)) {
2237 if (prev
->sched_class
->task_dead
)
2238 prev
->sched_class
->task_dead(prev
);
2241 * Remove function-return probe instances associated with this
2242 * task and put them back on the free list.
2244 kprobe_flush_task(prev
);
2245 put_task_struct(prev
);
2248 tick_nohz_task_switch(current
);
2254 /* rq->lock is NOT held, but preemption is disabled */
2255 static inline void post_schedule(struct rq
*rq
)
2257 if (rq
->post_schedule
) {
2258 unsigned long flags
;
2260 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2261 if (rq
->curr
->sched_class
->post_schedule
)
2262 rq
->curr
->sched_class
->post_schedule(rq
);
2263 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2265 rq
->post_schedule
= 0;
2271 static inline void post_schedule(struct rq
*rq
)
2278 * schedule_tail - first thing a freshly forked thread must call.
2279 * @prev: the thread we just switched away from.
2281 asmlinkage __visible
void schedule_tail(struct task_struct
*prev
)
2282 __releases(rq
->lock
)
2286 /* finish_task_switch() drops rq->lock and enables preemtion */
2288 rq
= finish_task_switch(prev
);
2292 if (current
->set_child_tid
)
2293 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2297 * context_switch - switch to the new MM and the new thread's register state.
2299 static inline struct rq
*
2300 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2301 struct task_struct
*next
)
2303 struct mm_struct
*mm
, *oldmm
;
2305 prepare_task_switch(rq
, prev
, next
);
2308 oldmm
= prev
->active_mm
;
2310 * For paravirt, this is coupled with an exit in switch_to to
2311 * combine the page table reload and the switch backend into
2314 arch_start_context_switch(prev
);
2317 next
->active_mm
= oldmm
;
2318 atomic_inc(&oldmm
->mm_count
);
2319 enter_lazy_tlb(oldmm
, next
);
2321 switch_mm(oldmm
, mm
, next
);
2324 prev
->active_mm
= NULL
;
2325 rq
->prev_mm
= oldmm
;
2328 * Since the runqueue lock will be released by the next
2329 * task (which is an invalid locking op but in the case
2330 * of the scheduler it's an obvious special-case), so we
2331 * do an early lockdep release here:
2333 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2335 context_tracking_task_switch(prev
, next
);
2336 /* Here we just switch the register state and the stack. */
2337 switch_to(prev
, next
, prev
);
2340 return finish_task_switch(prev
);
2344 * nr_running and nr_context_switches:
2346 * externally visible scheduler statistics: current number of runnable
2347 * threads, total number of context switches performed since bootup.
2349 unsigned long nr_running(void)
2351 unsigned long i
, sum
= 0;
2353 for_each_online_cpu(i
)
2354 sum
+= cpu_rq(i
)->nr_running
;
2360 * Check if only the current task is running on the cpu.
2362 bool single_task_running(void)
2364 if (cpu_rq(smp_processor_id())->nr_running
== 1)
2369 EXPORT_SYMBOL(single_task_running
);
2371 unsigned long long nr_context_switches(void)
2374 unsigned long long sum
= 0;
2376 for_each_possible_cpu(i
)
2377 sum
+= cpu_rq(i
)->nr_switches
;
2382 unsigned long nr_iowait(void)
2384 unsigned long i
, sum
= 0;
2386 for_each_possible_cpu(i
)
2387 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2392 unsigned long nr_iowait_cpu(int cpu
)
2394 struct rq
*this = cpu_rq(cpu
);
2395 return atomic_read(&this->nr_iowait
);
2398 void get_iowait_load(unsigned long *nr_waiters
, unsigned long *load
)
2400 struct rq
*this = this_rq();
2401 *nr_waiters
= atomic_read(&this->nr_iowait
);
2402 *load
= this->cpu_load
[0];
2408 * sched_exec - execve() is a valuable balancing opportunity, because at
2409 * this point the task has the smallest effective memory and cache footprint.
2411 void sched_exec(void)
2413 struct task_struct
*p
= current
;
2414 unsigned long flags
;
2417 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2418 dest_cpu
= p
->sched_class
->select_task_rq(p
, task_cpu(p
), SD_BALANCE_EXEC
, 0);
2419 if (dest_cpu
== smp_processor_id())
2422 if (likely(cpu_active(dest_cpu
))) {
2423 struct migration_arg arg
= { p
, dest_cpu
};
2425 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2426 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2430 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2435 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2436 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2438 EXPORT_PER_CPU_SYMBOL(kstat
);
2439 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2442 * Return accounted runtime for the task.
2443 * In case the task is currently running, return the runtime plus current's
2444 * pending runtime that have not been accounted yet.
2446 unsigned long long task_sched_runtime(struct task_struct
*p
)
2448 unsigned long flags
;
2452 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2454 * 64-bit doesn't need locks to atomically read a 64bit value.
2455 * So we have a optimization chance when the task's delta_exec is 0.
2456 * Reading ->on_cpu is racy, but this is ok.
2458 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2459 * If we race with it entering cpu, unaccounted time is 0. This is
2460 * indistinguishable from the read occurring a few cycles earlier.
2461 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
2462 * been accounted, so we're correct here as well.
2464 if (!p
->on_cpu
|| !task_on_rq_queued(p
))
2465 return p
->se
.sum_exec_runtime
;
2468 rq
= task_rq_lock(p
, &flags
);
2470 * Must be ->curr _and_ ->on_rq. If dequeued, we would
2471 * project cycles that may never be accounted to this
2472 * thread, breaking clock_gettime().
2474 if (task_current(rq
, p
) && task_on_rq_queued(p
)) {
2475 update_rq_clock(rq
);
2476 p
->sched_class
->update_curr(rq
);
2478 ns
= p
->se
.sum_exec_runtime
;
2479 task_rq_unlock(rq
, p
, &flags
);
2485 * This function gets called by the timer code, with HZ frequency.
2486 * We call it with interrupts disabled.
2488 void scheduler_tick(void)
2490 int cpu
= smp_processor_id();
2491 struct rq
*rq
= cpu_rq(cpu
);
2492 struct task_struct
*curr
= rq
->curr
;
2496 raw_spin_lock(&rq
->lock
);
2497 update_rq_clock(rq
);
2498 curr
->sched_class
->task_tick(rq
, curr
, 0);
2499 update_cpu_load_active(rq
);
2500 raw_spin_unlock(&rq
->lock
);
2502 perf_event_task_tick();
2505 rq
->idle_balance
= idle_cpu(cpu
);
2506 trigger_load_balance(rq
);
2508 rq_last_tick_reset(rq
);
2511 #ifdef CONFIG_NO_HZ_FULL
2513 * scheduler_tick_max_deferment
2515 * Keep at least one tick per second when a single
2516 * active task is running because the scheduler doesn't
2517 * yet completely support full dynticks environment.
2519 * This makes sure that uptime, CFS vruntime, load
2520 * balancing, etc... continue to move forward, even
2521 * with a very low granularity.
2523 * Return: Maximum deferment in nanoseconds.
2525 u64
scheduler_tick_max_deferment(void)
2527 struct rq
*rq
= this_rq();
2528 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2530 next
= rq
->last_sched_tick
+ HZ
;
2532 if (time_before_eq(next
, now
))
2535 return jiffies_to_nsecs(next
- now
);
2539 notrace
unsigned long get_parent_ip(unsigned long addr
)
2541 if (in_lock_functions(addr
)) {
2542 addr
= CALLER_ADDR2
;
2543 if (in_lock_functions(addr
))
2544 addr
= CALLER_ADDR3
;
2549 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2550 defined(CONFIG_PREEMPT_TRACER))
2552 void preempt_count_add(int val
)
2554 #ifdef CONFIG_DEBUG_PREEMPT
2558 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2561 __preempt_count_add(val
);
2562 #ifdef CONFIG_DEBUG_PREEMPT
2564 * Spinlock count overflowing soon?
2566 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2569 if (preempt_count() == val
) {
2570 unsigned long ip
= get_parent_ip(CALLER_ADDR1
);
2571 #ifdef CONFIG_DEBUG_PREEMPT
2572 current
->preempt_disable_ip
= ip
;
2574 trace_preempt_off(CALLER_ADDR0
, ip
);
2577 EXPORT_SYMBOL(preempt_count_add
);
2578 NOKPROBE_SYMBOL(preempt_count_add
);
2580 void preempt_count_sub(int val
)
2582 #ifdef CONFIG_DEBUG_PREEMPT
2586 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2589 * Is the spinlock portion underflowing?
2591 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2592 !(preempt_count() & PREEMPT_MASK
)))
2596 if (preempt_count() == val
)
2597 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2598 __preempt_count_sub(val
);
2600 EXPORT_SYMBOL(preempt_count_sub
);
2601 NOKPROBE_SYMBOL(preempt_count_sub
);
2606 * Print scheduling while atomic bug:
2608 static noinline
void __schedule_bug(struct task_struct
*prev
)
2610 if (oops_in_progress
)
2613 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2614 prev
->comm
, prev
->pid
, preempt_count());
2616 debug_show_held_locks(prev
);
2618 if (irqs_disabled())
2619 print_irqtrace_events(prev
);
2620 #ifdef CONFIG_DEBUG_PREEMPT
2621 if (in_atomic_preempt_off()) {
2622 pr_err("Preemption disabled at:");
2623 print_ip_sym(current
->preempt_disable_ip
);
2628 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2632 * Various schedule()-time debugging checks and statistics:
2634 static inline void schedule_debug(struct task_struct
*prev
)
2636 #ifdef CONFIG_SCHED_STACK_END_CHECK
2637 BUG_ON(unlikely(task_stack_end_corrupted(prev
)));
2640 * Test if we are atomic. Since do_exit() needs to call into
2641 * schedule() atomically, we ignore that path. Otherwise whine
2642 * if we are scheduling when we should not.
2644 if (unlikely(in_atomic_preempt_off() && prev
->state
!= TASK_DEAD
))
2645 __schedule_bug(prev
);
2648 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2650 schedstat_inc(this_rq(), sched_count
);
2654 * Pick up the highest-prio task:
2656 static inline struct task_struct
*
2657 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
2659 const struct sched_class
*class = &fair_sched_class
;
2660 struct task_struct
*p
;
2663 * Optimization: we know that if all tasks are in
2664 * the fair class we can call that function directly:
2666 if (likely(prev
->sched_class
== class &&
2667 rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2668 p
= fair_sched_class
.pick_next_task(rq
, prev
);
2669 if (unlikely(p
== RETRY_TASK
))
2672 /* assumes fair_sched_class->next == idle_sched_class */
2674 p
= idle_sched_class
.pick_next_task(rq
, prev
);
2680 for_each_class(class) {
2681 p
= class->pick_next_task(rq
, prev
);
2683 if (unlikely(p
== RETRY_TASK
))
2689 BUG(); /* the idle class will always have a runnable task */
2693 * __schedule() is the main scheduler function.
2695 * The main means of driving the scheduler and thus entering this function are:
2697 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2699 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2700 * paths. For example, see arch/x86/entry_64.S.
2702 * To drive preemption between tasks, the scheduler sets the flag in timer
2703 * interrupt handler scheduler_tick().
2705 * 3. Wakeups don't really cause entry into schedule(). They add a
2706 * task to the run-queue and that's it.
2708 * Now, if the new task added to the run-queue preempts the current
2709 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2710 * called on the nearest possible occasion:
2712 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2714 * - in syscall or exception context, at the next outmost
2715 * preempt_enable(). (this might be as soon as the wake_up()'s
2718 * - in IRQ context, return from interrupt-handler to
2719 * preemptible context
2721 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2724 * - cond_resched() call
2725 * - explicit schedule() call
2726 * - return from syscall or exception to user-space
2727 * - return from interrupt-handler to user-space
2729 * WARNING: all callers must re-check need_resched() afterward and reschedule
2730 * accordingly in case an event triggered the need for rescheduling (such as
2731 * an interrupt waking up a task) while preemption was disabled in __schedule().
2733 static void __sched
__schedule(void)
2735 struct task_struct
*prev
, *next
;
2736 unsigned long *switch_count
;
2741 cpu
= smp_processor_id();
2743 rcu_note_context_switch();
2746 schedule_debug(prev
);
2748 if (sched_feat(HRTICK
))
2752 * Make sure that signal_pending_state()->signal_pending() below
2753 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2754 * done by the caller to avoid the race with signal_wake_up().
2756 smp_mb__before_spinlock();
2757 raw_spin_lock_irq(&rq
->lock
);
2759 rq
->clock_skip_update
<<= 1; /* promote REQ to ACT */
2761 switch_count
= &prev
->nivcsw
;
2762 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2763 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2764 prev
->state
= TASK_RUNNING
;
2766 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2770 * If a worker went to sleep, notify and ask workqueue
2771 * whether it wants to wake up a task to maintain
2774 if (prev
->flags
& PF_WQ_WORKER
) {
2775 struct task_struct
*to_wakeup
;
2777 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2779 try_to_wake_up_local(to_wakeup
);
2782 switch_count
= &prev
->nvcsw
;
2785 if (task_on_rq_queued(prev
))
2786 update_rq_clock(rq
);
2788 next
= pick_next_task(rq
, prev
);
2789 clear_tsk_need_resched(prev
);
2790 clear_preempt_need_resched();
2791 rq
->clock_skip_update
= 0;
2793 if (likely(prev
!= next
)) {
2798 rq
= context_switch(rq
, prev
, next
); /* unlocks the rq */
2801 raw_spin_unlock_irq(&rq
->lock
);
2805 sched_preempt_enable_no_resched();
2808 static inline void sched_submit_work(struct task_struct
*tsk
)
2810 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2813 * If we are going to sleep and we have plugged IO queued,
2814 * make sure to submit it to avoid deadlocks.
2816 if (blk_needs_flush_plug(tsk
))
2817 blk_schedule_flush_plug(tsk
);
2820 asmlinkage __visible
void __sched
schedule(void)
2822 struct task_struct
*tsk
= current
;
2824 sched_submit_work(tsk
);
2827 } while (need_resched());
2829 EXPORT_SYMBOL(schedule
);
2831 #ifdef CONFIG_CONTEXT_TRACKING
2832 asmlinkage __visible
void __sched
schedule_user(void)
2835 * If we come here after a random call to set_need_resched(),
2836 * or we have been woken up remotely but the IPI has not yet arrived,
2837 * we haven't yet exited the RCU idle mode. Do it here manually until
2838 * we find a better solution.
2840 * NB: There are buggy callers of this function. Ideally we
2841 * should warn if prev_state != CONTEXT_USER, but that will trigger
2842 * too frequently to make sense yet.
2844 enum ctx_state prev_state
= exception_enter();
2846 exception_exit(prev_state
);
2851 * schedule_preempt_disabled - called with preemption disabled
2853 * Returns with preemption disabled. Note: preempt_count must be 1
2855 void __sched
schedule_preempt_disabled(void)
2857 sched_preempt_enable_no_resched();
2862 static void __sched notrace
preempt_schedule_common(void)
2865 __preempt_count_add(PREEMPT_ACTIVE
);
2867 __preempt_count_sub(PREEMPT_ACTIVE
);
2870 * Check again in case we missed a preemption opportunity
2871 * between schedule and now.
2874 } while (need_resched());
2877 #ifdef CONFIG_PREEMPT
2879 * this is the entry point to schedule() from in-kernel preemption
2880 * off of preempt_enable. Kernel preemptions off return from interrupt
2881 * occur there and call schedule directly.
2883 asmlinkage __visible
void __sched notrace
preempt_schedule(void)
2886 * If there is a non-zero preempt_count or interrupts are disabled,
2887 * we do not want to preempt the current task. Just return..
2889 if (likely(!preemptible()))
2892 preempt_schedule_common();
2894 NOKPROBE_SYMBOL(preempt_schedule
);
2895 EXPORT_SYMBOL(preempt_schedule
);
2897 #ifdef CONFIG_CONTEXT_TRACKING
2899 * preempt_schedule_context - preempt_schedule called by tracing
2901 * The tracing infrastructure uses preempt_enable_notrace to prevent
2902 * recursion and tracing preempt enabling caused by the tracing
2903 * infrastructure itself. But as tracing can happen in areas coming
2904 * from userspace or just about to enter userspace, a preempt enable
2905 * can occur before user_exit() is called. This will cause the scheduler
2906 * to be called when the system is still in usermode.
2908 * To prevent this, the preempt_enable_notrace will use this function
2909 * instead of preempt_schedule() to exit user context if needed before
2910 * calling the scheduler.
2912 asmlinkage __visible
void __sched notrace
preempt_schedule_context(void)
2914 enum ctx_state prev_ctx
;
2916 if (likely(!preemptible()))
2920 __preempt_count_add(PREEMPT_ACTIVE
);
2922 * Needs preempt disabled in case user_exit() is traced
2923 * and the tracer calls preempt_enable_notrace() causing
2924 * an infinite recursion.
2926 prev_ctx
= exception_enter();
2928 exception_exit(prev_ctx
);
2930 __preempt_count_sub(PREEMPT_ACTIVE
);
2932 } while (need_resched());
2934 EXPORT_SYMBOL_GPL(preempt_schedule_context
);
2935 #endif /* CONFIG_CONTEXT_TRACKING */
2937 #endif /* CONFIG_PREEMPT */
2940 * this is the entry point to schedule() from kernel preemption
2941 * off of irq context.
2942 * Note, that this is called and return with irqs disabled. This will
2943 * protect us against recursive calling from irq.
2945 asmlinkage __visible
void __sched
preempt_schedule_irq(void)
2947 enum ctx_state prev_state
;
2949 /* Catch callers which need to be fixed */
2950 BUG_ON(preempt_count() || !irqs_disabled());
2952 prev_state
= exception_enter();
2955 __preempt_count_add(PREEMPT_ACTIVE
);
2958 local_irq_disable();
2959 __preempt_count_sub(PREEMPT_ACTIVE
);
2962 * Check again in case we missed a preemption opportunity
2963 * between schedule and now.
2966 } while (need_resched());
2968 exception_exit(prev_state
);
2971 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2974 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2976 EXPORT_SYMBOL(default_wake_function
);
2978 #ifdef CONFIG_RT_MUTEXES
2981 * rt_mutex_setprio - set the current priority of a task
2983 * @prio: prio value (kernel-internal form)
2985 * This function changes the 'effective' priority of a task. It does
2986 * not touch ->normal_prio like __setscheduler().
2988 * Used by the rt_mutex code to implement priority inheritance
2989 * logic. Call site only calls if the priority of the task changed.
2991 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
2993 int oldprio
, queued
, running
, enqueue_flag
= 0;
2995 const struct sched_class
*prev_class
;
2997 BUG_ON(prio
> MAX_PRIO
);
2999 rq
= __task_rq_lock(p
);
3002 * Idle task boosting is a nono in general. There is one
3003 * exception, when PREEMPT_RT and NOHZ is active:
3005 * The idle task calls get_next_timer_interrupt() and holds
3006 * the timer wheel base->lock on the CPU and another CPU wants
3007 * to access the timer (probably to cancel it). We can safely
3008 * ignore the boosting request, as the idle CPU runs this code
3009 * with interrupts disabled and will complete the lock
3010 * protected section without being interrupted. So there is no
3011 * real need to boost.
3013 if (unlikely(p
== rq
->idle
)) {
3014 WARN_ON(p
!= rq
->curr
);
3015 WARN_ON(p
->pi_blocked_on
);
3019 trace_sched_pi_setprio(p
, prio
);
3021 prev_class
= p
->sched_class
;
3022 queued
= task_on_rq_queued(p
);
3023 running
= task_current(rq
, p
);
3025 dequeue_task(rq
, p
, 0);
3027 put_prev_task(rq
, p
);
3030 * Boosting condition are:
3031 * 1. -rt task is running and holds mutex A
3032 * --> -dl task blocks on mutex A
3034 * 2. -dl task is running and holds mutex A
3035 * --> -dl task blocks on mutex A and could preempt the
3038 if (dl_prio(prio
)) {
3039 struct task_struct
*pi_task
= rt_mutex_get_top_task(p
);
3040 if (!dl_prio(p
->normal_prio
) ||
3041 (pi_task
&& dl_entity_preempt(&pi_task
->dl
, &p
->dl
))) {
3042 p
->dl
.dl_boosted
= 1;
3043 p
->dl
.dl_throttled
= 0;
3044 enqueue_flag
= ENQUEUE_REPLENISH
;
3046 p
->dl
.dl_boosted
= 0;
3047 p
->sched_class
= &dl_sched_class
;
3048 } else if (rt_prio(prio
)) {
3049 if (dl_prio(oldprio
))
3050 p
->dl
.dl_boosted
= 0;
3052 enqueue_flag
= ENQUEUE_HEAD
;
3053 p
->sched_class
= &rt_sched_class
;
3055 if (dl_prio(oldprio
))
3056 p
->dl
.dl_boosted
= 0;
3057 if (rt_prio(oldprio
))
3059 p
->sched_class
= &fair_sched_class
;
3065 p
->sched_class
->set_curr_task(rq
);
3067 enqueue_task(rq
, p
, enqueue_flag
);
3069 check_class_changed(rq
, p
, prev_class
, oldprio
);
3071 __task_rq_unlock(rq
);
3075 void set_user_nice(struct task_struct
*p
, long nice
)
3077 int old_prio
, delta
, queued
;
3078 unsigned long flags
;
3081 if (task_nice(p
) == nice
|| nice
< MIN_NICE
|| nice
> MAX_NICE
)
3084 * We have to be careful, if called from sys_setpriority(),
3085 * the task might be in the middle of scheduling on another CPU.
3087 rq
= task_rq_lock(p
, &flags
);
3089 * The RT priorities are set via sched_setscheduler(), but we still
3090 * allow the 'normal' nice value to be set - but as expected
3091 * it wont have any effect on scheduling until the task is
3092 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3094 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
3095 p
->static_prio
= NICE_TO_PRIO(nice
);
3098 queued
= task_on_rq_queued(p
);
3100 dequeue_task(rq
, p
, 0);
3102 p
->static_prio
= NICE_TO_PRIO(nice
);
3105 p
->prio
= effective_prio(p
);
3106 delta
= p
->prio
- old_prio
;
3109 enqueue_task(rq
, p
, 0);
3111 * If the task increased its priority or is running and
3112 * lowered its priority, then reschedule its CPU:
3114 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3118 task_rq_unlock(rq
, p
, &flags
);
3120 EXPORT_SYMBOL(set_user_nice
);
3123 * can_nice - check if a task can reduce its nice value
3127 int can_nice(const struct task_struct
*p
, const int nice
)
3129 /* convert nice value [19,-20] to rlimit style value [1,40] */
3130 int nice_rlim
= nice_to_rlimit(nice
);
3132 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3133 capable(CAP_SYS_NICE
));
3136 #ifdef __ARCH_WANT_SYS_NICE
3139 * sys_nice - change the priority of the current process.
3140 * @increment: priority increment
3142 * sys_setpriority is a more generic, but much slower function that
3143 * does similar things.
3145 SYSCALL_DEFINE1(nice
, int, increment
)
3150 * Setpriority might change our priority at the same moment.
3151 * We don't have to worry. Conceptually one call occurs first
3152 * and we have a single winner.
3154 increment
= clamp(increment
, -NICE_WIDTH
, NICE_WIDTH
);
3155 nice
= task_nice(current
) + increment
;
3157 nice
= clamp_val(nice
, MIN_NICE
, MAX_NICE
);
3158 if (increment
< 0 && !can_nice(current
, nice
))
3161 retval
= security_task_setnice(current
, nice
);
3165 set_user_nice(current
, nice
);
3172 * task_prio - return the priority value of a given task.
3173 * @p: the task in question.
3175 * Return: The priority value as seen by users in /proc.
3176 * RT tasks are offset by -200. Normal tasks are centered
3177 * around 0, value goes from -16 to +15.
3179 int task_prio(const struct task_struct
*p
)
3181 return p
->prio
- MAX_RT_PRIO
;
3185 * idle_cpu - is a given cpu idle currently?
3186 * @cpu: the processor in question.
3188 * Return: 1 if the CPU is currently idle. 0 otherwise.
3190 int idle_cpu(int cpu
)
3192 struct rq
*rq
= cpu_rq(cpu
);
3194 if (rq
->curr
!= rq
->idle
)
3201 if (!llist_empty(&rq
->wake_list
))
3209 * idle_task - return the idle task for a given cpu.
3210 * @cpu: the processor in question.
3212 * Return: The idle task for the cpu @cpu.
3214 struct task_struct
*idle_task(int cpu
)
3216 return cpu_rq(cpu
)->idle
;
3220 * find_process_by_pid - find a process with a matching PID value.
3221 * @pid: the pid in question.
3223 * The task of @pid, if found. %NULL otherwise.
3225 static struct task_struct
*find_process_by_pid(pid_t pid
)
3227 return pid
? find_task_by_vpid(pid
) : current
;
3231 * This function initializes the sched_dl_entity of a newly becoming
3232 * SCHED_DEADLINE task.
3234 * Only the static values are considered here, the actual runtime and the
3235 * absolute deadline will be properly calculated when the task is enqueued
3236 * for the first time with its new policy.
3239 __setparam_dl(struct task_struct
*p
, const struct sched_attr
*attr
)
3241 struct sched_dl_entity
*dl_se
= &p
->dl
;
3243 dl_se
->dl_runtime
= attr
->sched_runtime
;
3244 dl_se
->dl_deadline
= attr
->sched_deadline
;
3245 dl_se
->dl_period
= attr
->sched_period
?: dl_se
->dl_deadline
;
3246 dl_se
->flags
= attr
->sched_flags
;
3247 dl_se
->dl_bw
= to_ratio(dl_se
->dl_period
, dl_se
->dl_runtime
);
3250 * Changing the parameters of a task is 'tricky' and we're not doing
3251 * the correct thing -- also see task_dead_dl() and switched_from_dl().
3253 * What we SHOULD do is delay the bandwidth release until the 0-lag
3254 * point. This would include retaining the task_struct until that time
3255 * and change dl_overflow() to not immediately decrement the current
3258 * Instead we retain the current runtime/deadline and let the new
3259 * parameters take effect after the current reservation period lapses.
3260 * This is safe (albeit pessimistic) because the 0-lag point is always
3261 * before the current scheduling deadline.
3263 * We can still have temporary overloads because we do not delay the
3264 * change in bandwidth until that time; so admission control is
3265 * not on the safe side. It does however guarantee tasks will never
3266 * consume more than promised.
3271 * sched_setparam() passes in -1 for its policy, to let the functions
3272 * it calls know not to change it.
3274 #define SETPARAM_POLICY -1
3276 static void __setscheduler_params(struct task_struct
*p
,
3277 const struct sched_attr
*attr
)
3279 int policy
= attr
->sched_policy
;
3281 if (policy
== SETPARAM_POLICY
)
3286 if (dl_policy(policy
))
3287 __setparam_dl(p
, attr
);
3288 else if (fair_policy(policy
))
3289 p
->static_prio
= NICE_TO_PRIO(attr
->sched_nice
);
3292 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3293 * !rt_policy. Always setting this ensures that things like
3294 * getparam()/getattr() don't report silly values for !rt tasks.
3296 p
->rt_priority
= attr
->sched_priority
;
3297 p
->normal_prio
= normal_prio(p
);
3301 /* Actually do priority change: must hold pi & rq lock. */
3302 static void __setscheduler(struct rq
*rq
, struct task_struct
*p
,
3303 const struct sched_attr
*attr
, bool keep_boost
)
3305 __setscheduler_params(p
, attr
);
3308 * Keep a potential priority boosting if called from
3309 * sched_setscheduler().
3312 p
->prio
= rt_mutex_get_effective_prio(p
, normal_prio(p
));
3314 p
->prio
= normal_prio(p
);
3316 if (dl_prio(p
->prio
))
3317 p
->sched_class
= &dl_sched_class
;
3318 else if (rt_prio(p
->prio
))
3319 p
->sched_class
= &rt_sched_class
;
3321 p
->sched_class
= &fair_sched_class
;
3325 __getparam_dl(struct task_struct
*p
, struct sched_attr
*attr
)
3327 struct sched_dl_entity
*dl_se
= &p
->dl
;
3329 attr
->sched_priority
= p
->rt_priority
;
3330 attr
->sched_runtime
= dl_se
->dl_runtime
;
3331 attr
->sched_deadline
= dl_se
->dl_deadline
;
3332 attr
->sched_period
= dl_se
->dl_period
;
3333 attr
->sched_flags
= dl_se
->flags
;
3337 * This function validates the new parameters of a -deadline task.
3338 * We ask for the deadline not being zero, and greater or equal
3339 * than the runtime, as well as the period of being zero or
3340 * greater than deadline. Furthermore, we have to be sure that
3341 * user parameters are above the internal resolution of 1us (we
3342 * check sched_runtime only since it is always the smaller one) and
3343 * below 2^63 ns (we have to check both sched_deadline and
3344 * sched_period, as the latter can be zero).
3347 __checkparam_dl(const struct sched_attr
*attr
)
3350 if (attr
->sched_deadline
== 0)
3354 * Since we truncate DL_SCALE bits, make sure we're at least
3357 if (attr
->sched_runtime
< (1ULL << DL_SCALE
))
3361 * Since we use the MSB for wrap-around and sign issues, make
3362 * sure it's not set (mind that period can be equal to zero).
3364 if (attr
->sched_deadline
& (1ULL << 63) ||
3365 attr
->sched_period
& (1ULL << 63))
3368 /* runtime <= deadline <= period (if period != 0) */
3369 if ((attr
->sched_period
!= 0 &&
3370 attr
->sched_period
< attr
->sched_deadline
) ||
3371 attr
->sched_deadline
< attr
->sched_runtime
)
3378 * check the target process has a UID that matches the current process's
3380 static bool check_same_owner(struct task_struct
*p
)
3382 const struct cred
*cred
= current_cred(), *pcred
;
3386 pcred
= __task_cred(p
);
3387 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3388 uid_eq(cred
->euid
, pcred
->uid
));
3393 static bool dl_param_changed(struct task_struct
*p
,
3394 const struct sched_attr
*attr
)
3396 struct sched_dl_entity
*dl_se
= &p
->dl
;
3398 if (dl_se
->dl_runtime
!= attr
->sched_runtime
||
3399 dl_se
->dl_deadline
!= attr
->sched_deadline
||
3400 dl_se
->dl_period
!= attr
->sched_period
||
3401 dl_se
->flags
!= attr
->sched_flags
)
3407 static int __sched_setscheduler(struct task_struct
*p
,
3408 const struct sched_attr
*attr
,
3411 int newprio
= dl_policy(attr
->sched_policy
) ? MAX_DL_PRIO
- 1 :
3412 MAX_RT_PRIO
- 1 - attr
->sched_priority
;
3413 int retval
, oldprio
, oldpolicy
= -1, queued
, running
;
3414 int new_effective_prio
, policy
= attr
->sched_policy
;
3415 unsigned long flags
;
3416 const struct sched_class
*prev_class
;
3420 /* may grab non-irq protected spin_locks */
3421 BUG_ON(in_interrupt());
3423 /* double check policy once rq lock held */
3425 reset_on_fork
= p
->sched_reset_on_fork
;
3426 policy
= oldpolicy
= p
->policy
;
3428 reset_on_fork
= !!(attr
->sched_flags
& SCHED_FLAG_RESET_ON_FORK
);
3430 if (policy
!= SCHED_DEADLINE
&&
3431 policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3432 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3433 policy
!= SCHED_IDLE
)
3437 if (attr
->sched_flags
& ~(SCHED_FLAG_RESET_ON_FORK
))
3441 * Valid priorities for SCHED_FIFO and SCHED_RR are
3442 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3443 * SCHED_BATCH and SCHED_IDLE is 0.
3445 if ((p
->mm
&& attr
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3446 (!p
->mm
&& attr
->sched_priority
> MAX_RT_PRIO
-1))
3448 if ((dl_policy(policy
) && !__checkparam_dl(attr
)) ||
3449 (rt_policy(policy
) != (attr
->sched_priority
!= 0)))
3453 * Allow unprivileged RT tasks to decrease priority:
3455 if (user
&& !capable(CAP_SYS_NICE
)) {
3456 if (fair_policy(policy
)) {
3457 if (attr
->sched_nice
< task_nice(p
) &&
3458 !can_nice(p
, attr
->sched_nice
))
3462 if (rt_policy(policy
)) {
3463 unsigned long rlim_rtprio
=
3464 task_rlimit(p
, RLIMIT_RTPRIO
);
3466 /* can't set/change the rt policy */
3467 if (policy
!= p
->policy
&& !rlim_rtprio
)
3470 /* can't increase priority */
3471 if (attr
->sched_priority
> p
->rt_priority
&&
3472 attr
->sched_priority
> rlim_rtprio
)
3477 * Can't set/change SCHED_DEADLINE policy at all for now
3478 * (safest behavior); in the future we would like to allow
3479 * unprivileged DL tasks to increase their relative deadline
3480 * or reduce their runtime (both ways reducing utilization)
3482 if (dl_policy(policy
))
3486 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3487 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3489 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3490 if (!can_nice(p
, task_nice(p
)))
3494 /* can't change other user's priorities */
3495 if (!check_same_owner(p
))
3498 /* Normal users shall not reset the sched_reset_on_fork flag */
3499 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3504 retval
= security_task_setscheduler(p
);
3510 * make sure no PI-waiters arrive (or leave) while we are
3511 * changing the priority of the task:
3513 * To be able to change p->policy safely, the appropriate
3514 * runqueue lock must be held.
3516 rq
= task_rq_lock(p
, &flags
);
3519 * Changing the policy of the stop threads its a very bad idea
3521 if (p
== rq
->stop
) {
3522 task_rq_unlock(rq
, p
, &flags
);
3527 * If not changing anything there's no need to proceed further,
3528 * but store a possible modification of reset_on_fork.
3530 if (unlikely(policy
== p
->policy
)) {
3531 if (fair_policy(policy
) && attr
->sched_nice
!= task_nice(p
))
3533 if (rt_policy(policy
) && attr
->sched_priority
!= p
->rt_priority
)
3535 if (dl_policy(policy
) && dl_param_changed(p
, attr
))
3538 p
->sched_reset_on_fork
= reset_on_fork
;
3539 task_rq_unlock(rq
, p
, &flags
);
3545 #ifdef CONFIG_RT_GROUP_SCHED
3547 * Do not allow realtime tasks into groups that have no runtime
3550 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3551 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3552 !task_group_is_autogroup(task_group(p
))) {
3553 task_rq_unlock(rq
, p
, &flags
);
3558 if (dl_bandwidth_enabled() && dl_policy(policy
)) {
3559 cpumask_t
*span
= rq
->rd
->span
;
3562 * Don't allow tasks with an affinity mask smaller than
3563 * the entire root_domain to become SCHED_DEADLINE. We
3564 * will also fail if there's no bandwidth available.
3566 if (!cpumask_subset(span
, &p
->cpus_allowed
) ||
3567 rq
->rd
->dl_bw
.bw
== 0) {
3568 task_rq_unlock(rq
, p
, &flags
);
3575 /* recheck policy now with rq lock held */
3576 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3577 policy
= oldpolicy
= -1;
3578 task_rq_unlock(rq
, p
, &flags
);
3583 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3584 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3587 if ((dl_policy(policy
) || dl_task(p
)) && dl_overflow(p
, policy
, attr
)) {
3588 task_rq_unlock(rq
, p
, &flags
);
3592 p
->sched_reset_on_fork
= reset_on_fork
;
3596 * Take priority boosted tasks into account. If the new
3597 * effective priority is unchanged, we just store the new
3598 * normal parameters and do not touch the scheduler class and
3599 * the runqueue. This will be done when the task deboost
3602 new_effective_prio
= rt_mutex_get_effective_prio(p
, newprio
);
3603 if (new_effective_prio
== oldprio
) {
3604 __setscheduler_params(p
, attr
);
3605 task_rq_unlock(rq
, p
, &flags
);
3609 queued
= task_on_rq_queued(p
);
3610 running
= task_current(rq
, p
);
3612 dequeue_task(rq
, p
, 0);
3614 put_prev_task(rq
, p
);
3616 prev_class
= p
->sched_class
;
3617 __setscheduler(rq
, p
, attr
, true);
3620 p
->sched_class
->set_curr_task(rq
);
3623 * We enqueue to tail when the priority of a task is
3624 * increased (user space view).
3626 enqueue_task(rq
, p
, oldprio
<= p
->prio
? ENQUEUE_HEAD
: 0);
3629 check_class_changed(rq
, p
, prev_class
, oldprio
);
3630 task_rq_unlock(rq
, p
, &flags
);
3632 rt_mutex_adjust_pi(p
);
3637 static int _sched_setscheduler(struct task_struct
*p
, int policy
,
3638 const struct sched_param
*param
, bool check
)
3640 struct sched_attr attr
= {
3641 .sched_policy
= policy
,
3642 .sched_priority
= param
->sched_priority
,
3643 .sched_nice
= PRIO_TO_NICE(p
->static_prio
),
3646 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
3647 if ((policy
!= SETPARAM_POLICY
) && (policy
& SCHED_RESET_ON_FORK
)) {
3648 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3649 policy
&= ~SCHED_RESET_ON_FORK
;
3650 attr
.sched_policy
= policy
;
3653 return __sched_setscheduler(p
, &attr
, check
);
3656 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3657 * @p: the task in question.
3658 * @policy: new policy.
3659 * @param: structure containing the new RT priority.
3661 * Return: 0 on success. An error code otherwise.
3663 * NOTE that the task may be already dead.
3665 int sched_setscheduler(struct task_struct
*p
, int policy
,
3666 const struct sched_param
*param
)
3668 return _sched_setscheduler(p
, policy
, param
, true);
3670 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3672 int sched_setattr(struct task_struct
*p
, const struct sched_attr
*attr
)
3674 return __sched_setscheduler(p
, attr
, true);
3676 EXPORT_SYMBOL_GPL(sched_setattr
);
3679 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3680 * @p: the task in question.
3681 * @policy: new policy.
3682 * @param: structure containing the new RT priority.
3684 * Just like sched_setscheduler, only don't bother checking if the
3685 * current context has permission. For example, this is needed in
3686 * stop_machine(): we create temporary high priority worker threads,
3687 * but our caller might not have that capability.
3689 * Return: 0 on success. An error code otherwise.
3691 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3692 const struct sched_param
*param
)
3694 return _sched_setscheduler(p
, policy
, param
, false);
3698 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3700 struct sched_param lparam
;
3701 struct task_struct
*p
;
3704 if (!param
|| pid
< 0)
3706 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3711 p
= find_process_by_pid(pid
);
3713 retval
= sched_setscheduler(p
, policy
, &lparam
);
3720 * Mimics kernel/events/core.c perf_copy_attr().
3722 static int sched_copy_attr(struct sched_attr __user
*uattr
,
3723 struct sched_attr
*attr
)
3728 if (!access_ok(VERIFY_WRITE
, uattr
, SCHED_ATTR_SIZE_VER0
))
3732 * zero the full structure, so that a short copy will be nice.
3734 memset(attr
, 0, sizeof(*attr
));
3736 ret
= get_user(size
, &uattr
->size
);
3740 if (size
> PAGE_SIZE
) /* silly large */
3743 if (!size
) /* abi compat */
3744 size
= SCHED_ATTR_SIZE_VER0
;
3746 if (size
< SCHED_ATTR_SIZE_VER0
)
3750 * If we're handed a bigger struct than we know of,
3751 * ensure all the unknown bits are 0 - i.e. new
3752 * user-space does not rely on any kernel feature
3753 * extensions we dont know about yet.
3755 if (size
> sizeof(*attr
)) {
3756 unsigned char __user
*addr
;
3757 unsigned char __user
*end
;
3760 addr
= (void __user
*)uattr
+ sizeof(*attr
);
3761 end
= (void __user
*)uattr
+ size
;
3763 for (; addr
< end
; addr
++) {
3764 ret
= get_user(val
, addr
);
3770 size
= sizeof(*attr
);
3773 ret
= copy_from_user(attr
, uattr
, size
);
3778 * XXX: do we want to be lenient like existing syscalls; or do we want
3779 * to be strict and return an error on out-of-bounds values?
3781 attr
->sched_nice
= clamp(attr
->sched_nice
, MIN_NICE
, MAX_NICE
);
3786 put_user(sizeof(*attr
), &uattr
->size
);
3791 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3792 * @pid: the pid in question.
3793 * @policy: new policy.
3794 * @param: structure containing the new RT priority.
3796 * Return: 0 on success. An error code otherwise.
3798 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3799 struct sched_param __user
*, param
)
3801 /* negative values for policy are not valid */
3805 return do_sched_setscheduler(pid
, policy
, param
);
3809 * sys_sched_setparam - set/change the RT priority of a thread
3810 * @pid: the pid in question.
3811 * @param: structure containing the new RT priority.
3813 * Return: 0 on success. An error code otherwise.
3815 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3817 return do_sched_setscheduler(pid
, SETPARAM_POLICY
, param
);
3821 * sys_sched_setattr - same as above, but with extended sched_attr
3822 * @pid: the pid in question.
3823 * @uattr: structure containing the extended parameters.
3824 * @flags: for future extension.
3826 SYSCALL_DEFINE3(sched_setattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3827 unsigned int, flags
)
3829 struct sched_attr attr
;
3830 struct task_struct
*p
;
3833 if (!uattr
|| pid
< 0 || flags
)
3836 retval
= sched_copy_attr(uattr
, &attr
);
3840 if ((int)attr
.sched_policy
< 0)
3845 p
= find_process_by_pid(pid
);
3847 retval
= sched_setattr(p
, &attr
);
3854 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3855 * @pid: the pid in question.
3857 * Return: On success, the policy of the thread. Otherwise, a negative error
3860 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3862 struct task_struct
*p
;
3870 p
= find_process_by_pid(pid
);
3872 retval
= security_task_getscheduler(p
);
3875 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3882 * sys_sched_getparam - get the RT priority of a thread
3883 * @pid: the pid in question.
3884 * @param: structure containing the RT priority.
3886 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3889 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3891 struct sched_param lp
= { .sched_priority
= 0 };
3892 struct task_struct
*p
;
3895 if (!param
|| pid
< 0)
3899 p
= find_process_by_pid(pid
);
3904 retval
= security_task_getscheduler(p
);
3908 if (task_has_rt_policy(p
))
3909 lp
.sched_priority
= p
->rt_priority
;
3913 * This one might sleep, we cannot do it with a spinlock held ...
3915 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3924 static int sched_read_attr(struct sched_attr __user
*uattr
,
3925 struct sched_attr
*attr
,
3930 if (!access_ok(VERIFY_WRITE
, uattr
, usize
))
3934 * If we're handed a smaller struct than we know of,
3935 * ensure all the unknown bits are 0 - i.e. old
3936 * user-space does not get uncomplete information.
3938 if (usize
< sizeof(*attr
)) {
3939 unsigned char *addr
;
3942 addr
= (void *)attr
+ usize
;
3943 end
= (void *)attr
+ sizeof(*attr
);
3945 for (; addr
< end
; addr
++) {
3953 ret
= copy_to_user(uattr
, attr
, attr
->size
);
3961 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
3962 * @pid: the pid in question.
3963 * @uattr: structure containing the extended parameters.
3964 * @size: sizeof(attr) for fwd/bwd comp.
3965 * @flags: for future extension.
3967 SYSCALL_DEFINE4(sched_getattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3968 unsigned int, size
, unsigned int, flags
)
3970 struct sched_attr attr
= {
3971 .size
= sizeof(struct sched_attr
),
3973 struct task_struct
*p
;
3976 if (!uattr
|| pid
< 0 || size
> PAGE_SIZE
||
3977 size
< SCHED_ATTR_SIZE_VER0
|| flags
)
3981 p
= find_process_by_pid(pid
);
3986 retval
= security_task_getscheduler(p
);
3990 attr
.sched_policy
= p
->policy
;
3991 if (p
->sched_reset_on_fork
)
3992 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3993 if (task_has_dl_policy(p
))
3994 __getparam_dl(p
, &attr
);
3995 else if (task_has_rt_policy(p
))
3996 attr
.sched_priority
= p
->rt_priority
;
3998 attr
.sched_nice
= task_nice(p
);
4002 retval
= sched_read_attr(uattr
, &attr
, size
);
4010 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4012 cpumask_var_t cpus_allowed
, new_mask
;
4013 struct task_struct
*p
;
4018 p
= find_process_by_pid(pid
);
4024 /* Prevent p going away */
4028 if (p
->flags
& PF_NO_SETAFFINITY
) {
4032 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4036 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4038 goto out_free_cpus_allowed
;
4041 if (!check_same_owner(p
)) {
4043 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
4045 goto out_free_new_mask
;
4050 retval
= security_task_setscheduler(p
);
4052 goto out_free_new_mask
;
4055 cpuset_cpus_allowed(p
, cpus_allowed
);
4056 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4059 * Since bandwidth control happens on root_domain basis,
4060 * if admission test is enabled, we only admit -deadline
4061 * tasks allowed to run on all the CPUs in the task's
4065 if (task_has_dl_policy(p
) && dl_bandwidth_enabled()) {
4067 if (!cpumask_subset(task_rq(p
)->rd
->span
, new_mask
)) {
4070 goto out_free_new_mask
;
4076 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4079 cpuset_cpus_allowed(p
, cpus_allowed
);
4080 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4082 * We must have raced with a concurrent cpuset
4083 * update. Just reset the cpus_allowed to the
4084 * cpuset's cpus_allowed
4086 cpumask_copy(new_mask
, cpus_allowed
);
4091 free_cpumask_var(new_mask
);
4092 out_free_cpus_allowed
:
4093 free_cpumask_var(cpus_allowed
);
4099 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4100 struct cpumask
*new_mask
)
4102 if (len
< cpumask_size())
4103 cpumask_clear(new_mask
);
4104 else if (len
> cpumask_size())
4105 len
= cpumask_size();
4107 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4111 * sys_sched_setaffinity - set the cpu affinity of a process
4112 * @pid: pid of the process
4113 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4114 * @user_mask_ptr: user-space pointer to the new cpu mask
4116 * Return: 0 on success. An error code otherwise.
4118 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4119 unsigned long __user
*, user_mask_ptr
)
4121 cpumask_var_t new_mask
;
4124 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4127 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4129 retval
= sched_setaffinity(pid
, new_mask
);
4130 free_cpumask_var(new_mask
);
4134 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4136 struct task_struct
*p
;
4137 unsigned long flags
;
4143 p
= find_process_by_pid(pid
);
4147 retval
= security_task_getscheduler(p
);
4151 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4152 cpumask_and(mask
, &p
->cpus_allowed
, cpu_active_mask
);
4153 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4162 * sys_sched_getaffinity - get the cpu affinity of a process
4163 * @pid: pid of the process
4164 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4165 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4167 * Return: 0 on success. An error code otherwise.
4169 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4170 unsigned long __user
*, user_mask_ptr
)
4175 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4177 if (len
& (sizeof(unsigned long)-1))
4180 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4183 ret
= sched_getaffinity(pid
, mask
);
4185 size_t retlen
= min_t(size_t, len
, cpumask_size());
4187 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4192 free_cpumask_var(mask
);
4198 * sys_sched_yield - yield the current processor to other threads.
4200 * This function yields the current CPU to other tasks. If there are no
4201 * other threads running on this CPU then this function will return.
4205 SYSCALL_DEFINE0(sched_yield
)
4207 struct rq
*rq
= this_rq_lock();
4209 schedstat_inc(rq
, yld_count
);
4210 current
->sched_class
->yield_task(rq
);
4213 * Since we are going to call schedule() anyway, there's
4214 * no need to preempt or enable interrupts:
4216 __release(rq
->lock
);
4217 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4218 do_raw_spin_unlock(&rq
->lock
);
4219 sched_preempt_enable_no_resched();
4226 int __sched
_cond_resched(void)
4228 if (should_resched()) {
4229 preempt_schedule_common();
4234 EXPORT_SYMBOL(_cond_resched
);
4237 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4238 * call schedule, and on return reacquire the lock.
4240 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4241 * operations here to prevent schedule() from being called twice (once via
4242 * spin_unlock(), once by hand).
4244 int __cond_resched_lock(spinlock_t
*lock
)
4246 int resched
= should_resched();
4249 lockdep_assert_held(lock
);
4251 if (spin_needbreak(lock
) || resched
) {
4254 preempt_schedule_common();
4262 EXPORT_SYMBOL(__cond_resched_lock
);
4264 int __sched
__cond_resched_softirq(void)
4266 BUG_ON(!in_softirq());
4268 if (should_resched()) {
4270 preempt_schedule_common();
4276 EXPORT_SYMBOL(__cond_resched_softirq
);
4279 * yield - yield the current processor to other threads.
4281 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4283 * The scheduler is at all times free to pick the calling task as the most
4284 * eligible task to run, if removing the yield() call from your code breaks
4285 * it, its already broken.
4287 * Typical broken usage is:
4292 * where one assumes that yield() will let 'the other' process run that will
4293 * make event true. If the current task is a SCHED_FIFO task that will never
4294 * happen. Never use yield() as a progress guarantee!!
4296 * If you want to use yield() to wait for something, use wait_event().
4297 * If you want to use yield() to be 'nice' for others, use cond_resched().
4298 * If you still want to use yield(), do not!
4300 void __sched
yield(void)
4302 set_current_state(TASK_RUNNING
);
4305 EXPORT_SYMBOL(yield
);
4308 * yield_to - yield the current processor to another thread in
4309 * your thread group, or accelerate that thread toward the
4310 * processor it's on.
4312 * @preempt: whether task preemption is allowed or not
4314 * It's the caller's job to ensure that the target task struct
4315 * can't go away on us before we can do any checks.
4318 * true (>0) if we indeed boosted the target task.
4319 * false (0) if we failed to boost the target.
4320 * -ESRCH if there's no task to yield to.
4322 int __sched
yield_to(struct task_struct
*p
, bool preempt
)
4324 struct task_struct
*curr
= current
;
4325 struct rq
*rq
, *p_rq
;
4326 unsigned long flags
;
4329 local_irq_save(flags
);
4335 * If we're the only runnable task on the rq and target rq also
4336 * has only one task, there's absolutely no point in yielding.
4338 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
4343 double_rq_lock(rq
, p_rq
);
4344 if (task_rq(p
) != p_rq
) {
4345 double_rq_unlock(rq
, p_rq
);
4349 if (!curr
->sched_class
->yield_to_task
)
4352 if (curr
->sched_class
!= p
->sched_class
)
4355 if (task_running(p_rq
, p
) || p
->state
)
4358 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4360 schedstat_inc(rq
, yld_count
);
4362 * Make p's CPU reschedule; pick_next_entity takes care of
4365 if (preempt
&& rq
!= p_rq
)
4370 double_rq_unlock(rq
, p_rq
);
4372 local_irq_restore(flags
);
4379 EXPORT_SYMBOL_GPL(yield_to
);
4382 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4383 * that process accounting knows that this is a task in IO wait state.
4385 long __sched
io_schedule_timeout(long timeout
)
4387 int old_iowait
= current
->in_iowait
;
4391 current
->in_iowait
= 1;
4393 blk_schedule_flush_plug(current
);
4395 blk_flush_plug(current
);
4397 delayacct_blkio_start();
4399 atomic_inc(&rq
->nr_iowait
);
4400 ret
= schedule_timeout(timeout
);
4401 current
->in_iowait
= old_iowait
;
4402 atomic_dec(&rq
->nr_iowait
);
4403 delayacct_blkio_end();
4407 EXPORT_SYMBOL(io_schedule_timeout
);
4410 * sys_sched_get_priority_max - return maximum RT priority.
4411 * @policy: scheduling class.
4413 * Return: On success, this syscall returns the maximum
4414 * rt_priority that can be used by a given scheduling class.
4415 * On failure, a negative error code is returned.
4417 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4424 ret
= MAX_USER_RT_PRIO
-1;
4426 case SCHED_DEADLINE
:
4437 * sys_sched_get_priority_min - return minimum RT priority.
4438 * @policy: scheduling class.
4440 * Return: On success, this syscall returns the minimum
4441 * rt_priority that can be used by a given scheduling class.
4442 * On failure, a negative error code is returned.
4444 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4453 case SCHED_DEADLINE
:
4463 * sys_sched_rr_get_interval - return the default timeslice of a process.
4464 * @pid: pid of the process.
4465 * @interval: userspace pointer to the timeslice value.
4467 * this syscall writes the default timeslice value of a given process
4468 * into the user-space timespec buffer. A value of '0' means infinity.
4470 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4473 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4474 struct timespec __user
*, interval
)
4476 struct task_struct
*p
;
4477 unsigned int time_slice
;
4478 unsigned long flags
;
4488 p
= find_process_by_pid(pid
);
4492 retval
= security_task_getscheduler(p
);
4496 rq
= task_rq_lock(p
, &flags
);
4498 if (p
->sched_class
->get_rr_interval
)
4499 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4500 task_rq_unlock(rq
, p
, &flags
);
4503 jiffies_to_timespec(time_slice
, &t
);
4504 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4512 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4514 void sched_show_task(struct task_struct
*p
)
4516 unsigned long free
= 0;
4518 unsigned long state
= p
->state
;
4521 state
= __ffs(state
) + 1;
4522 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4523 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4524 #if BITS_PER_LONG == 32
4525 if (state
== TASK_RUNNING
)
4526 printk(KERN_CONT
" running ");
4528 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4530 if (state
== TASK_RUNNING
)
4531 printk(KERN_CONT
" running task ");
4533 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4535 #ifdef CONFIG_DEBUG_STACK_USAGE
4536 free
= stack_not_used(p
);
4541 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4543 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4544 task_pid_nr(p
), ppid
,
4545 (unsigned long)task_thread_info(p
)->flags
);
4547 print_worker_info(KERN_INFO
, p
);
4548 show_stack(p
, NULL
);
4551 void show_state_filter(unsigned long state_filter
)
4553 struct task_struct
*g
, *p
;
4555 #if BITS_PER_LONG == 32
4557 " task PC stack pid father\n");
4560 " task PC stack pid father\n");
4563 for_each_process_thread(g
, p
) {
4565 * reset the NMI-timeout, listing all files on a slow
4566 * console might take a lot of time:
4568 touch_nmi_watchdog();
4569 if (!state_filter
|| (p
->state
& state_filter
))
4573 touch_all_softlockup_watchdogs();
4575 #ifdef CONFIG_SCHED_DEBUG
4576 sysrq_sched_debug_show();
4580 * Only show locks if all tasks are dumped:
4583 debug_show_all_locks();
4586 void init_idle_bootup_task(struct task_struct
*idle
)
4588 idle
->sched_class
= &idle_sched_class
;
4592 * init_idle - set up an idle thread for a given CPU
4593 * @idle: task in question
4594 * @cpu: cpu the idle task belongs to
4596 * NOTE: this function does not set the idle thread's NEED_RESCHED
4597 * flag, to make booting more robust.
4599 void init_idle(struct task_struct
*idle
, int cpu
)
4601 struct rq
*rq
= cpu_rq(cpu
);
4602 unsigned long flags
;
4604 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4606 __sched_fork(0, idle
);
4607 idle
->state
= TASK_RUNNING
;
4608 idle
->se
.exec_start
= sched_clock();
4610 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4612 * We're having a chicken and egg problem, even though we are
4613 * holding rq->lock, the cpu isn't yet set to this cpu so the
4614 * lockdep check in task_group() will fail.
4616 * Similar case to sched_fork(). / Alternatively we could
4617 * use task_rq_lock() here and obtain the other rq->lock.
4622 __set_task_cpu(idle
, cpu
);
4625 rq
->curr
= rq
->idle
= idle
;
4626 idle
->on_rq
= TASK_ON_RQ_QUEUED
;
4627 #if defined(CONFIG_SMP)
4630 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4632 /* Set the preempt count _outside_ the spinlocks! */
4633 init_idle_preempt_count(idle
, cpu
);
4636 * The idle tasks have their own, simple scheduling class:
4638 idle
->sched_class
= &idle_sched_class
;
4639 ftrace_graph_init_idle_task(idle
, cpu
);
4640 vtime_init_idle(idle
, cpu
);
4641 #if defined(CONFIG_SMP)
4642 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4646 int cpuset_cpumask_can_shrink(const struct cpumask
*cur
,
4647 const struct cpumask
*trial
)
4649 int ret
= 1, trial_cpus
;
4650 struct dl_bw
*cur_dl_b
;
4651 unsigned long flags
;
4653 if (!cpumask_weight(cur
))
4656 rcu_read_lock_sched();
4657 cur_dl_b
= dl_bw_of(cpumask_any(cur
));
4658 trial_cpus
= cpumask_weight(trial
);
4660 raw_spin_lock_irqsave(&cur_dl_b
->lock
, flags
);
4661 if (cur_dl_b
->bw
!= -1 &&
4662 cur_dl_b
->bw
* trial_cpus
< cur_dl_b
->total_bw
)
4664 raw_spin_unlock_irqrestore(&cur_dl_b
->lock
, flags
);
4665 rcu_read_unlock_sched();
4670 int task_can_attach(struct task_struct
*p
,
4671 const struct cpumask
*cs_cpus_allowed
)
4676 * Kthreads which disallow setaffinity shouldn't be moved
4677 * to a new cpuset; we don't want to change their cpu
4678 * affinity and isolating such threads by their set of
4679 * allowed nodes is unnecessary. Thus, cpusets are not
4680 * applicable for such threads. This prevents checking for
4681 * success of set_cpus_allowed_ptr() on all attached tasks
4682 * before cpus_allowed may be changed.
4684 if (p
->flags
& PF_NO_SETAFFINITY
) {
4690 if (dl_task(p
) && !cpumask_intersects(task_rq(p
)->rd
->span
,
4692 unsigned int dest_cpu
= cpumask_any_and(cpu_active_mask
,
4697 unsigned long flags
;
4699 rcu_read_lock_sched();
4700 dl_b
= dl_bw_of(dest_cpu
);
4701 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
4702 cpus
= dl_bw_cpus(dest_cpu
);
4703 overflow
= __dl_overflow(dl_b
, cpus
, 0, p
->dl
.dl_bw
);
4708 * We reserve space for this task in the destination
4709 * root_domain, as we can't fail after this point.
4710 * We will free resources in the source root_domain
4711 * later on (see set_cpus_allowed_dl()).
4713 __dl_add(dl_b
, p
->dl
.dl_bw
);
4715 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
4716 rcu_read_unlock_sched();
4726 * move_queued_task - move a queued task to new rq.
4728 * Returns (locked) new rq. Old rq's lock is released.
4730 static struct rq
*move_queued_task(struct task_struct
*p
, int new_cpu
)
4732 struct rq
*rq
= task_rq(p
);
4734 lockdep_assert_held(&rq
->lock
);
4736 dequeue_task(rq
, p
, 0);
4737 p
->on_rq
= TASK_ON_RQ_MIGRATING
;
4738 set_task_cpu(p
, new_cpu
);
4739 raw_spin_unlock(&rq
->lock
);
4741 rq
= cpu_rq(new_cpu
);
4743 raw_spin_lock(&rq
->lock
);
4744 BUG_ON(task_cpu(p
) != new_cpu
);
4745 p
->on_rq
= TASK_ON_RQ_QUEUED
;
4746 enqueue_task(rq
, p
, 0);
4747 check_preempt_curr(rq
, p
, 0);
4752 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4754 if (p
->sched_class
->set_cpus_allowed
)
4755 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4757 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4758 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4762 * This is how migration works:
4764 * 1) we invoke migration_cpu_stop() on the target CPU using
4766 * 2) stopper starts to run (implicitly forcing the migrated thread
4768 * 3) it checks whether the migrated task is still in the wrong runqueue.
4769 * 4) if it's in the wrong runqueue then the migration thread removes
4770 * it and puts it into the right queue.
4771 * 5) stopper completes and stop_one_cpu() returns and the migration
4776 * Change a given task's CPU affinity. Migrate the thread to a
4777 * proper CPU and schedule it away if the CPU it's executing on
4778 * is removed from the allowed bitmask.
4780 * NOTE: the caller must have a valid reference to the task, the
4781 * task must not exit() & deallocate itself prematurely. The
4782 * call is not atomic; no spinlocks may be held.
4784 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4786 unsigned long flags
;
4788 unsigned int dest_cpu
;
4791 rq
= task_rq_lock(p
, &flags
);
4793 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4796 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4801 do_set_cpus_allowed(p
, new_mask
);
4803 /* Can the task run on the task's current CPU? If so, we're done */
4804 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4807 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4808 if (task_running(rq
, p
) || p
->state
== TASK_WAKING
) {
4809 struct migration_arg arg
= { p
, dest_cpu
};
4810 /* Need help from migration thread: drop lock and wait. */
4811 task_rq_unlock(rq
, p
, &flags
);
4812 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4813 tlb_migrate_finish(p
->mm
);
4815 } else if (task_on_rq_queued(p
))
4816 rq
= move_queued_task(p
, dest_cpu
);
4818 task_rq_unlock(rq
, p
, &flags
);
4822 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4825 * Move (not current) task off this cpu, onto dest cpu. We're doing
4826 * this because either it can't run here any more (set_cpus_allowed()
4827 * away from this CPU, or CPU going down), or because we're
4828 * attempting to rebalance this task on exec (sched_exec).
4830 * So we race with normal scheduler movements, but that's OK, as long
4831 * as the task is no longer on this CPU.
4833 * Returns non-zero if task was successfully migrated.
4835 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4840 if (unlikely(!cpu_active(dest_cpu
)))
4843 rq
= cpu_rq(src_cpu
);
4845 raw_spin_lock(&p
->pi_lock
);
4846 raw_spin_lock(&rq
->lock
);
4847 /* Already moved. */
4848 if (task_cpu(p
) != src_cpu
)
4851 /* Affinity changed (again). */
4852 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4856 * If we're not on a rq, the next wake-up will ensure we're
4859 if (task_on_rq_queued(p
))
4860 rq
= move_queued_task(p
, dest_cpu
);
4864 raw_spin_unlock(&rq
->lock
);
4865 raw_spin_unlock(&p
->pi_lock
);
4869 #ifdef CONFIG_NUMA_BALANCING
4870 /* Migrate current task p to target_cpu */
4871 int migrate_task_to(struct task_struct
*p
, int target_cpu
)
4873 struct migration_arg arg
= { p
, target_cpu
};
4874 int curr_cpu
= task_cpu(p
);
4876 if (curr_cpu
== target_cpu
)
4879 if (!cpumask_test_cpu(target_cpu
, tsk_cpus_allowed(p
)))
4882 /* TODO: This is not properly updating schedstats */
4884 trace_sched_move_numa(p
, curr_cpu
, target_cpu
);
4885 return stop_one_cpu(curr_cpu
, migration_cpu_stop
, &arg
);
4889 * Requeue a task on a given node and accurately track the number of NUMA
4890 * tasks on the runqueues
4892 void sched_setnuma(struct task_struct
*p
, int nid
)
4895 unsigned long flags
;
4896 bool queued
, running
;
4898 rq
= task_rq_lock(p
, &flags
);
4899 queued
= task_on_rq_queued(p
);
4900 running
= task_current(rq
, p
);
4903 dequeue_task(rq
, p
, 0);
4905 put_prev_task(rq
, p
);
4907 p
->numa_preferred_nid
= nid
;
4910 p
->sched_class
->set_curr_task(rq
);
4912 enqueue_task(rq
, p
, 0);
4913 task_rq_unlock(rq
, p
, &flags
);
4918 * migration_cpu_stop - this will be executed by a highprio stopper thread
4919 * and performs thread migration by bumping thread off CPU then
4920 * 'pushing' onto another runqueue.
4922 static int migration_cpu_stop(void *data
)
4924 struct migration_arg
*arg
= data
;
4927 * The original target cpu might have gone down and we might
4928 * be on another cpu but it doesn't matter.
4930 local_irq_disable();
4932 * We need to explicitly wake pending tasks before running
4933 * __migrate_task() such that we will not miss enforcing cpus_allowed
4934 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
4936 sched_ttwu_pending();
4937 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4942 #ifdef CONFIG_HOTPLUG_CPU
4945 * Ensures that the idle task is using init_mm right before its cpu goes
4948 void idle_task_exit(void)
4950 struct mm_struct
*mm
= current
->active_mm
;
4952 BUG_ON(cpu_online(smp_processor_id()));
4954 if (mm
!= &init_mm
) {
4955 switch_mm(mm
, &init_mm
, current
);
4956 finish_arch_post_lock_switch();
4962 * Since this CPU is going 'away' for a while, fold any nr_active delta
4963 * we might have. Assumes we're called after migrate_tasks() so that the
4964 * nr_active count is stable.
4966 * Also see the comment "Global load-average calculations".
4968 static void calc_load_migrate(struct rq
*rq
)
4970 long delta
= calc_load_fold_active(rq
);
4972 atomic_long_add(delta
, &calc_load_tasks
);
4975 static void put_prev_task_fake(struct rq
*rq
, struct task_struct
*prev
)
4979 static const struct sched_class fake_sched_class
= {
4980 .put_prev_task
= put_prev_task_fake
,
4983 static struct task_struct fake_task
= {
4985 * Avoid pull_{rt,dl}_task()
4987 .prio
= MAX_PRIO
+ 1,
4988 .sched_class
= &fake_sched_class
,
4992 * Migrate all tasks from the rq, sleeping tasks will be migrated by
4993 * try_to_wake_up()->select_task_rq().
4995 * Called with rq->lock held even though we'er in stop_machine() and
4996 * there's no concurrency possible, we hold the required locks anyway
4997 * because of lock validation efforts.
4999 static void migrate_tasks(unsigned int dead_cpu
)
5001 struct rq
*rq
= cpu_rq(dead_cpu
);
5002 struct task_struct
*next
, *stop
= rq
->stop
;
5006 * Fudge the rq selection such that the below task selection loop
5007 * doesn't get stuck on the currently eligible stop task.
5009 * We're currently inside stop_machine() and the rq is either stuck
5010 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5011 * either way we should never end up calling schedule() until we're
5017 * put_prev_task() and pick_next_task() sched
5018 * class method both need to have an up-to-date
5019 * value of rq->clock[_task]
5021 update_rq_clock(rq
);
5025 * There's this thread running, bail when that's the only
5028 if (rq
->nr_running
== 1)
5031 next
= pick_next_task(rq
, &fake_task
);
5033 next
->sched_class
->put_prev_task(rq
, next
);
5035 /* Find suitable destination for @next, with force if needed. */
5036 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
5037 raw_spin_unlock(&rq
->lock
);
5039 __migrate_task(next
, dead_cpu
, dest_cpu
);
5041 raw_spin_lock(&rq
->lock
);
5047 #endif /* CONFIG_HOTPLUG_CPU */
5049 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5051 static struct ctl_table sd_ctl_dir
[] = {
5053 .procname
= "sched_domain",
5059 static struct ctl_table sd_ctl_root
[] = {
5061 .procname
= "kernel",
5063 .child
= sd_ctl_dir
,
5068 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5070 struct ctl_table
*entry
=
5071 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5076 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5078 struct ctl_table
*entry
;
5081 * In the intermediate directories, both the child directory and
5082 * procname are dynamically allocated and could fail but the mode
5083 * will always be set. In the lowest directory the names are
5084 * static strings and all have proc handlers.
5086 for (entry
= *tablep
; entry
->mode
; entry
++) {
5088 sd_free_ctl_entry(&entry
->child
);
5089 if (entry
->proc_handler
== NULL
)
5090 kfree(entry
->procname
);
5097 static int min_load_idx
= 0;
5098 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
5101 set_table_entry(struct ctl_table
*entry
,
5102 const char *procname
, void *data
, int maxlen
,
5103 umode_t mode
, proc_handler
*proc_handler
,
5106 entry
->procname
= procname
;
5108 entry
->maxlen
= maxlen
;
5110 entry
->proc_handler
= proc_handler
;
5113 entry
->extra1
= &min_load_idx
;
5114 entry
->extra2
= &max_load_idx
;
5118 static struct ctl_table
*
5119 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5121 struct ctl_table
*table
= sd_alloc_ctl_entry(14);
5126 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5127 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5128 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5129 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5130 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5131 sizeof(int), 0644, proc_dointvec_minmax
, true);
5132 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5133 sizeof(int), 0644, proc_dointvec_minmax
, true);
5134 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5135 sizeof(int), 0644, proc_dointvec_minmax
, true);
5136 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5137 sizeof(int), 0644, proc_dointvec_minmax
, true);
5138 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5139 sizeof(int), 0644, proc_dointvec_minmax
, true);
5140 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5141 sizeof(int), 0644, proc_dointvec_minmax
, false);
5142 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5143 sizeof(int), 0644, proc_dointvec_minmax
, false);
5144 set_table_entry(&table
[9], "cache_nice_tries",
5145 &sd
->cache_nice_tries
,
5146 sizeof(int), 0644, proc_dointvec_minmax
, false);
5147 set_table_entry(&table
[10], "flags", &sd
->flags
,
5148 sizeof(int), 0644, proc_dointvec_minmax
, false);
5149 set_table_entry(&table
[11], "max_newidle_lb_cost",
5150 &sd
->max_newidle_lb_cost
,
5151 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5152 set_table_entry(&table
[12], "name", sd
->name
,
5153 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
5154 /* &table[13] is terminator */
5159 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5161 struct ctl_table
*entry
, *table
;
5162 struct sched_domain
*sd
;
5163 int domain_num
= 0, i
;
5166 for_each_domain(cpu
, sd
)
5168 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5173 for_each_domain(cpu
, sd
) {
5174 snprintf(buf
, 32, "domain%d", i
);
5175 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5177 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5184 static struct ctl_table_header
*sd_sysctl_header
;
5185 static void register_sched_domain_sysctl(void)
5187 int i
, cpu_num
= num_possible_cpus();
5188 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5191 WARN_ON(sd_ctl_dir
[0].child
);
5192 sd_ctl_dir
[0].child
= entry
;
5197 for_each_possible_cpu(i
) {
5198 snprintf(buf
, 32, "cpu%d", i
);
5199 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5201 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5205 WARN_ON(sd_sysctl_header
);
5206 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5209 /* may be called multiple times per register */
5210 static void unregister_sched_domain_sysctl(void)
5212 if (sd_sysctl_header
)
5213 unregister_sysctl_table(sd_sysctl_header
);
5214 sd_sysctl_header
= NULL
;
5215 if (sd_ctl_dir
[0].child
)
5216 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5219 static void register_sched_domain_sysctl(void)
5222 static void unregister_sched_domain_sysctl(void)
5227 static void set_rq_online(struct rq
*rq
)
5230 const struct sched_class
*class;
5232 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5235 for_each_class(class) {
5236 if (class->rq_online
)
5237 class->rq_online(rq
);
5242 static void set_rq_offline(struct rq
*rq
)
5245 const struct sched_class
*class;
5247 for_each_class(class) {
5248 if (class->rq_offline
)
5249 class->rq_offline(rq
);
5252 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5258 * migration_call - callback that gets triggered when a CPU is added.
5259 * Here we can start up the necessary migration thread for the new CPU.
5262 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5264 int cpu
= (long)hcpu
;
5265 unsigned long flags
;
5266 struct rq
*rq
= cpu_rq(cpu
);
5268 switch (action
& ~CPU_TASKS_FROZEN
) {
5270 case CPU_UP_PREPARE
:
5271 rq
->calc_load_update
= calc_load_update
;
5275 /* Update our root-domain */
5276 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5278 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5282 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5285 #ifdef CONFIG_HOTPLUG_CPU
5287 sched_ttwu_pending();
5288 /* Update our root-domain */
5289 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5291 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5295 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5296 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5300 calc_load_migrate(rq
);
5305 update_max_interval();
5311 * Register at high priority so that task migration (migrate_all_tasks)
5312 * happens before everything else. This has to be lower priority than
5313 * the notifier in the perf_event subsystem, though.
5315 static struct notifier_block migration_notifier
= {
5316 .notifier_call
= migration_call
,
5317 .priority
= CPU_PRI_MIGRATION
,
5320 static void __cpuinit
set_cpu_rq_start_time(void)
5322 int cpu
= smp_processor_id();
5323 struct rq
*rq
= cpu_rq(cpu
);
5324 rq
->age_stamp
= sched_clock_cpu(cpu
);
5327 static int sched_cpu_active(struct notifier_block
*nfb
,
5328 unsigned long action
, void *hcpu
)
5330 switch (action
& ~CPU_TASKS_FROZEN
) {
5332 set_cpu_rq_start_time();
5334 case CPU_DOWN_FAILED
:
5335 set_cpu_active((long)hcpu
, true);
5342 static int sched_cpu_inactive(struct notifier_block
*nfb
,
5343 unsigned long action
, void *hcpu
)
5345 switch (action
& ~CPU_TASKS_FROZEN
) {
5346 case CPU_DOWN_PREPARE
:
5347 set_cpu_active((long)hcpu
, false);
5354 static int __init
migration_init(void)
5356 void *cpu
= (void *)(long)smp_processor_id();
5359 /* Initialize migration for the boot CPU */
5360 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5361 BUG_ON(err
== NOTIFY_BAD
);
5362 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5363 register_cpu_notifier(&migration_notifier
);
5365 /* Register cpu active notifiers */
5366 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5367 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5371 early_initcall(migration_init
);
5376 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5378 #ifdef CONFIG_SCHED_DEBUG
5380 static __read_mostly
int sched_debug_enabled
;
5382 static int __init
sched_debug_setup(char *str
)
5384 sched_debug_enabled
= 1;
5388 early_param("sched_debug", sched_debug_setup
);
5390 static inline bool sched_debug(void)
5392 return sched_debug_enabled
;
5395 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5396 struct cpumask
*groupmask
)
5398 struct sched_group
*group
= sd
->groups
;
5400 cpumask_clear(groupmask
);
5402 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5404 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5405 printk("does not load-balance\n");
5407 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5412 printk(KERN_CONT
"span %*pbl level %s\n",
5413 cpumask_pr_args(sched_domain_span(sd
)), sd
->name
);
5415 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5416 printk(KERN_ERR
"ERROR: domain->span does not contain "
5419 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5420 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5424 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5428 printk(KERN_ERR
"ERROR: group is NULL\n");
5432 if (!cpumask_weight(sched_group_cpus(group
))) {
5433 printk(KERN_CONT
"\n");
5434 printk(KERN_ERR
"ERROR: empty group\n");
5438 if (!(sd
->flags
& SD_OVERLAP
) &&
5439 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5440 printk(KERN_CONT
"\n");
5441 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5445 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5447 printk(KERN_CONT
" %*pbl",
5448 cpumask_pr_args(sched_group_cpus(group
)));
5449 if (group
->sgc
->capacity
!= SCHED_CAPACITY_SCALE
) {
5450 printk(KERN_CONT
" (cpu_capacity = %d)",
5451 group
->sgc
->capacity
);
5454 group
= group
->next
;
5455 } while (group
!= sd
->groups
);
5456 printk(KERN_CONT
"\n");
5458 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5459 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5462 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5463 printk(KERN_ERR
"ERROR: parent span is not a superset "
5464 "of domain->span\n");
5468 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5472 if (!sched_debug_enabled
)
5476 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5480 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5483 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5491 #else /* !CONFIG_SCHED_DEBUG */
5492 # define sched_domain_debug(sd, cpu) do { } while (0)
5493 static inline bool sched_debug(void)
5497 #endif /* CONFIG_SCHED_DEBUG */
5499 static int sd_degenerate(struct sched_domain
*sd
)
5501 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5504 /* Following flags need at least 2 groups */
5505 if (sd
->flags
& (SD_LOAD_BALANCE
|
5506 SD_BALANCE_NEWIDLE
|
5509 SD_SHARE_CPUCAPACITY
|
5510 SD_SHARE_PKG_RESOURCES
|
5511 SD_SHARE_POWERDOMAIN
)) {
5512 if (sd
->groups
!= sd
->groups
->next
)
5516 /* Following flags don't use groups */
5517 if (sd
->flags
& (SD_WAKE_AFFINE
))
5524 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5526 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5528 if (sd_degenerate(parent
))
5531 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5534 /* Flags needing groups don't count if only 1 group in parent */
5535 if (parent
->groups
== parent
->groups
->next
) {
5536 pflags
&= ~(SD_LOAD_BALANCE
|
5537 SD_BALANCE_NEWIDLE
|
5540 SD_SHARE_CPUCAPACITY
|
5541 SD_SHARE_PKG_RESOURCES
|
5543 SD_SHARE_POWERDOMAIN
);
5544 if (nr_node_ids
== 1)
5545 pflags
&= ~SD_SERIALIZE
;
5547 if (~cflags
& pflags
)
5553 static void free_rootdomain(struct rcu_head
*rcu
)
5555 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5557 cpupri_cleanup(&rd
->cpupri
);
5558 cpudl_cleanup(&rd
->cpudl
);
5559 free_cpumask_var(rd
->dlo_mask
);
5560 free_cpumask_var(rd
->rto_mask
);
5561 free_cpumask_var(rd
->online
);
5562 free_cpumask_var(rd
->span
);
5566 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5568 struct root_domain
*old_rd
= NULL
;
5569 unsigned long flags
;
5571 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5576 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5579 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5582 * If we dont want to free the old_rd yet then
5583 * set old_rd to NULL to skip the freeing later
5586 if (!atomic_dec_and_test(&old_rd
->refcount
))
5590 atomic_inc(&rd
->refcount
);
5593 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5594 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5597 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5600 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5603 static int init_rootdomain(struct root_domain
*rd
)
5605 memset(rd
, 0, sizeof(*rd
));
5607 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5609 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5611 if (!alloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
5613 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5616 init_dl_bw(&rd
->dl_bw
);
5617 if (cpudl_init(&rd
->cpudl
) != 0)
5620 if (cpupri_init(&rd
->cpupri
) != 0)
5625 free_cpumask_var(rd
->rto_mask
);
5627 free_cpumask_var(rd
->dlo_mask
);
5629 free_cpumask_var(rd
->online
);
5631 free_cpumask_var(rd
->span
);
5637 * By default the system creates a single root-domain with all cpus as
5638 * members (mimicking the global state we have today).
5640 struct root_domain def_root_domain
;
5642 static void init_defrootdomain(void)
5644 init_rootdomain(&def_root_domain
);
5646 atomic_set(&def_root_domain
.refcount
, 1);
5649 static struct root_domain
*alloc_rootdomain(void)
5651 struct root_domain
*rd
;
5653 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5657 if (init_rootdomain(rd
) != 0) {
5665 static void free_sched_groups(struct sched_group
*sg
, int free_sgc
)
5667 struct sched_group
*tmp
, *first
;
5676 if (free_sgc
&& atomic_dec_and_test(&sg
->sgc
->ref
))
5681 } while (sg
!= first
);
5684 static void free_sched_domain(struct rcu_head
*rcu
)
5686 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5689 * If its an overlapping domain it has private groups, iterate and
5692 if (sd
->flags
& SD_OVERLAP
) {
5693 free_sched_groups(sd
->groups
, 1);
5694 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5695 kfree(sd
->groups
->sgc
);
5701 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5703 call_rcu(&sd
->rcu
, free_sched_domain
);
5706 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5708 for (; sd
; sd
= sd
->parent
)
5709 destroy_sched_domain(sd
, cpu
);
5713 * Keep a special pointer to the highest sched_domain that has
5714 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5715 * allows us to avoid some pointer chasing select_idle_sibling().
5717 * Also keep a unique ID per domain (we use the first cpu number in
5718 * the cpumask of the domain), this allows us to quickly tell if
5719 * two cpus are in the same cache domain, see cpus_share_cache().
5721 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5722 DEFINE_PER_CPU(int, sd_llc_size
);
5723 DEFINE_PER_CPU(int, sd_llc_id
);
5724 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
5725 DEFINE_PER_CPU(struct sched_domain
*, sd_busy
);
5726 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
5728 static void update_top_cache_domain(int cpu
)
5730 struct sched_domain
*sd
;
5731 struct sched_domain
*busy_sd
= NULL
;
5735 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5737 id
= cpumask_first(sched_domain_span(sd
));
5738 size
= cpumask_weight(sched_domain_span(sd
));
5739 busy_sd
= sd
->parent
; /* sd_busy */
5741 rcu_assign_pointer(per_cpu(sd_busy
, cpu
), busy_sd
);
5743 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5744 per_cpu(sd_llc_size
, cpu
) = size
;
5745 per_cpu(sd_llc_id
, cpu
) = id
;
5747 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
5748 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
5750 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
5751 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
5755 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5756 * hold the hotplug lock.
5759 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5761 struct rq
*rq
= cpu_rq(cpu
);
5762 struct sched_domain
*tmp
;
5764 /* Remove the sched domains which do not contribute to scheduling. */
5765 for (tmp
= sd
; tmp
; ) {
5766 struct sched_domain
*parent
= tmp
->parent
;
5770 if (sd_parent_degenerate(tmp
, parent
)) {
5771 tmp
->parent
= parent
->parent
;
5773 parent
->parent
->child
= tmp
;
5775 * Transfer SD_PREFER_SIBLING down in case of a
5776 * degenerate parent; the spans match for this
5777 * so the property transfers.
5779 if (parent
->flags
& SD_PREFER_SIBLING
)
5780 tmp
->flags
|= SD_PREFER_SIBLING
;
5781 destroy_sched_domain(parent
, cpu
);
5786 if (sd
&& sd_degenerate(sd
)) {
5789 destroy_sched_domain(tmp
, cpu
);
5794 sched_domain_debug(sd
, cpu
);
5796 rq_attach_root(rq
, rd
);
5798 rcu_assign_pointer(rq
->sd
, sd
);
5799 destroy_sched_domains(tmp
, cpu
);
5801 update_top_cache_domain(cpu
);
5804 /* Setup the mask of cpus configured for isolated domains */
5805 static int __init
isolated_cpu_setup(char *str
)
5807 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5808 cpulist_parse(str
, cpu_isolated_map
);
5812 __setup("isolcpus=", isolated_cpu_setup
);
5815 struct sched_domain
** __percpu sd
;
5816 struct root_domain
*rd
;
5827 * Build an iteration mask that can exclude certain CPUs from the upwards
5830 * Asymmetric node setups can result in situations where the domain tree is of
5831 * unequal depth, make sure to skip domains that already cover the entire
5834 * In that case build_sched_domains() will have terminated the iteration early
5835 * and our sibling sd spans will be empty. Domains should always include the
5836 * cpu they're built on, so check that.
5839 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5841 const struct cpumask
*span
= sched_domain_span(sd
);
5842 struct sd_data
*sdd
= sd
->private;
5843 struct sched_domain
*sibling
;
5846 for_each_cpu(i
, span
) {
5847 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5848 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5851 cpumask_set_cpu(i
, sched_group_mask(sg
));
5856 * Return the canonical balance cpu for this group, this is the first cpu
5857 * of this group that's also in the iteration mask.
5859 int group_balance_cpu(struct sched_group
*sg
)
5861 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5865 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5867 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5868 const struct cpumask
*span
= sched_domain_span(sd
);
5869 struct cpumask
*covered
= sched_domains_tmpmask
;
5870 struct sd_data
*sdd
= sd
->private;
5871 struct sched_domain
*sibling
;
5874 cpumask_clear(covered
);
5876 for_each_cpu(i
, span
) {
5877 struct cpumask
*sg_span
;
5879 if (cpumask_test_cpu(i
, covered
))
5882 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5884 /* See the comment near build_group_mask(). */
5885 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5888 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5889 GFP_KERNEL
, cpu_to_node(cpu
));
5894 sg_span
= sched_group_cpus(sg
);
5896 cpumask_copy(sg_span
, sched_domain_span(sibling
->child
));
5898 cpumask_set_cpu(i
, sg_span
);
5900 cpumask_or(covered
, covered
, sg_span
);
5902 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, i
);
5903 if (atomic_inc_return(&sg
->sgc
->ref
) == 1)
5904 build_group_mask(sd
, sg
);
5907 * Initialize sgc->capacity such that even if we mess up the
5908 * domains and no possible iteration will get us here, we won't
5911 sg
->sgc
->capacity
= SCHED_CAPACITY_SCALE
* cpumask_weight(sg_span
);
5914 * Make sure the first group of this domain contains the
5915 * canonical balance cpu. Otherwise the sched_domain iteration
5916 * breaks. See update_sg_lb_stats().
5918 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5919 group_balance_cpu(sg
) == cpu
)
5929 sd
->groups
= groups
;
5934 free_sched_groups(first
, 0);
5939 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5941 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5942 struct sched_domain
*child
= sd
->child
;
5945 cpu
= cpumask_first(sched_domain_span(child
));
5948 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
5949 (*sg
)->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
5950 atomic_set(&(*sg
)->sgc
->ref
, 1); /* for claim_allocations */
5957 * build_sched_groups will build a circular linked list of the groups
5958 * covered by the given span, and will set each group's ->cpumask correctly,
5959 * and ->cpu_capacity to 0.
5961 * Assumes the sched_domain tree is fully constructed
5964 build_sched_groups(struct sched_domain
*sd
, int cpu
)
5966 struct sched_group
*first
= NULL
, *last
= NULL
;
5967 struct sd_data
*sdd
= sd
->private;
5968 const struct cpumask
*span
= sched_domain_span(sd
);
5969 struct cpumask
*covered
;
5972 get_group(cpu
, sdd
, &sd
->groups
);
5973 atomic_inc(&sd
->groups
->ref
);
5975 if (cpu
!= cpumask_first(span
))
5978 lockdep_assert_held(&sched_domains_mutex
);
5979 covered
= sched_domains_tmpmask
;
5981 cpumask_clear(covered
);
5983 for_each_cpu(i
, span
) {
5984 struct sched_group
*sg
;
5987 if (cpumask_test_cpu(i
, covered
))
5990 group
= get_group(i
, sdd
, &sg
);
5991 cpumask_setall(sched_group_mask(sg
));
5993 for_each_cpu(j
, span
) {
5994 if (get_group(j
, sdd
, NULL
) != group
)
5997 cpumask_set_cpu(j
, covered
);
5998 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6013 * Initialize sched groups cpu_capacity.
6015 * cpu_capacity indicates the capacity of sched group, which is used while
6016 * distributing the load between different sched groups in a sched domain.
6017 * Typically cpu_capacity for all the groups in a sched domain will be same
6018 * unless there are asymmetries in the topology. If there are asymmetries,
6019 * group having more cpu_capacity will pickup more load compared to the
6020 * group having less cpu_capacity.
6022 static void init_sched_groups_capacity(int cpu
, struct sched_domain
*sd
)
6024 struct sched_group
*sg
= sd
->groups
;
6029 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
6031 } while (sg
!= sd
->groups
);
6033 if (cpu
!= group_balance_cpu(sg
))
6036 update_group_capacity(sd
, cpu
);
6037 atomic_set(&sg
->sgc
->nr_busy_cpus
, sg
->group_weight
);
6041 * Initializers for schedule domains
6042 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6045 static int default_relax_domain_level
= -1;
6046 int sched_domain_level_max
;
6048 static int __init
setup_relax_domain_level(char *str
)
6050 if (kstrtoint(str
, 0, &default_relax_domain_level
))
6051 pr_warn("Unable to set relax_domain_level\n");
6055 __setup("relax_domain_level=", setup_relax_domain_level
);
6057 static void set_domain_attribute(struct sched_domain
*sd
,
6058 struct sched_domain_attr
*attr
)
6062 if (!attr
|| attr
->relax_domain_level
< 0) {
6063 if (default_relax_domain_level
< 0)
6066 request
= default_relax_domain_level
;
6068 request
= attr
->relax_domain_level
;
6069 if (request
< sd
->level
) {
6070 /* turn off idle balance on this domain */
6071 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6073 /* turn on idle balance on this domain */
6074 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6078 static void __sdt_free(const struct cpumask
*cpu_map
);
6079 static int __sdt_alloc(const struct cpumask
*cpu_map
);
6081 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6082 const struct cpumask
*cpu_map
)
6086 if (!atomic_read(&d
->rd
->refcount
))
6087 free_rootdomain(&d
->rd
->rcu
); /* fall through */
6089 free_percpu(d
->sd
); /* fall through */
6091 __sdt_free(cpu_map
); /* fall through */
6097 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6098 const struct cpumask
*cpu_map
)
6100 memset(d
, 0, sizeof(*d
));
6102 if (__sdt_alloc(cpu_map
))
6103 return sa_sd_storage
;
6104 d
->sd
= alloc_percpu(struct sched_domain
*);
6106 return sa_sd_storage
;
6107 d
->rd
= alloc_rootdomain();
6110 return sa_rootdomain
;
6114 * NULL the sd_data elements we've used to build the sched_domain and
6115 * sched_group structure so that the subsequent __free_domain_allocs()
6116 * will not free the data we're using.
6118 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
6120 struct sd_data
*sdd
= sd
->private;
6122 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
6123 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
6125 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
6126 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
6128 if (atomic_read(&(*per_cpu_ptr(sdd
->sgc
, cpu
))->ref
))
6129 *per_cpu_ptr(sdd
->sgc
, cpu
) = NULL
;
6133 static int sched_domains_numa_levels
;
6134 enum numa_topology_type sched_numa_topology_type
;
6135 static int *sched_domains_numa_distance
;
6136 int sched_max_numa_distance
;
6137 static struct cpumask
***sched_domains_numa_masks
;
6138 static int sched_domains_curr_level
;
6142 * SD_flags allowed in topology descriptions.
6144 * SD_SHARE_CPUCAPACITY - describes SMT topologies
6145 * SD_SHARE_PKG_RESOURCES - describes shared caches
6146 * SD_NUMA - describes NUMA topologies
6147 * SD_SHARE_POWERDOMAIN - describes shared power domain
6150 * SD_ASYM_PACKING - describes SMT quirks
6152 #define TOPOLOGY_SD_FLAGS \
6153 (SD_SHARE_CPUCAPACITY | \
6154 SD_SHARE_PKG_RESOURCES | \
6157 SD_SHARE_POWERDOMAIN)
6159 static struct sched_domain
*
6160 sd_init(struct sched_domain_topology_level
*tl
, int cpu
)
6162 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
6163 int sd_weight
, sd_flags
= 0;
6167 * Ugly hack to pass state to sd_numa_mask()...
6169 sched_domains_curr_level
= tl
->numa_level
;
6172 sd_weight
= cpumask_weight(tl
->mask(cpu
));
6175 sd_flags
= (*tl
->sd_flags
)();
6176 if (WARN_ONCE(sd_flags
& ~TOPOLOGY_SD_FLAGS
,
6177 "wrong sd_flags in topology description\n"))
6178 sd_flags
&= ~TOPOLOGY_SD_FLAGS
;
6180 *sd
= (struct sched_domain
){
6181 .min_interval
= sd_weight
,
6182 .max_interval
= 2*sd_weight
,
6184 .imbalance_pct
= 125,
6186 .cache_nice_tries
= 0,
6193 .flags
= 1*SD_LOAD_BALANCE
6194 | 1*SD_BALANCE_NEWIDLE
6199 | 0*SD_SHARE_CPUCAPACITY
6200 | 0*SD_SHARE_PKG_RESOURCES
6202 | 0*SD_PREFER_SIBLING
6207 .last_balance
= jiffies
,
6208 .balance_interval
= sd_weight
,
6210 .max_newidle_lb_cost
= 0,
6211 .next_decay_max_lb_cost
= jiffies
,
6212 #ifdef CONFIG_SCHED_DEBUG
6218 * Convert topological properties into behaviour.
6221 if (sd
->flags
& SD_SHARE_CPUCAPACITY
) {
6222 sd
->flags
|= SD_PREFER_SIBLING
;
6223 sd
->imbalance_pct
= 110;
6224 sd
->smt_gain
= 1178; /* ~15% */
6226 } else if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
6227 sd
->imbalance_pct
= 117;
6228 sd
->cache_nice_tries
= 1;
6232 } else if (sd
->flags
& SD_NUMA
) {
6233 sd
->cache_nice_tries
= 2;
6237 sd
->flags
|= SD_SERIALIZE
;
6238 if (sched_domains_numa_distance
[tl
->numa_level
] > RECLAIM_DISTANCE
) {
6239 sd
->flags
&= ~(SD_BALANCE_EXEC
|
6246 sd
->flags
|= SD_PREFER_SIBLING
;
6247 sd
->cache_nice_tries
= 1;
6252 sd
->private = &tl
->data
;
6258 * Topology list, bottom-up.
6260 static struct sched_domain_topology_level default_topology
[] = {
6261 #ifdef CONFIG_SCHED_SMT
6262 { cpu_smt_mask
, cpu_smt_flags
, SD_INIT_NAME(SMT
) },
6264 #ifdef CONFIG_SCHED_MC
6265 { cpu_coregroup_mask
, cpu_core_flags
, SD_INIT_NAME(MC
) },
6267 { cpu_cpu_mask
, SD_INIT_NAME(DIE
) },
6271 struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6273 #define for_each_sd_topology(tl) \
6274 for (tl = sched_domain_topology; tl->mask; tl++)
6276 void set_sched_topology(struct sched_domain_topology_level
*tl
)
6278 sched_domain_topology
= tl
;
6283 static const struct cpumask
*sd_numa_mask(int cpu
)
6285 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6288 static void sched_numa_warn(const char *str
)
6290 static int done
= false;
6298 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6300 for (i
= 0; i
< nr_node_ids
; i
++) {
6301 printk(KERN_WARNING
" ");
6302 for (j
= 0; j
< nr_node_ids
; j
++)
6303 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6304 printk(KERN_CONT
"\n");
6306 printk(KERN_WARNING
"\n");
6309 bool find_numa_distance(int distance
)
6313 if (distance
== node_distance(0, 0))
6316 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6317 if (sched_domains_numa_distance
[i
] == distance
)
6325 * A system can have three types of NUMA topology:
6326 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
6327 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
6328 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
6330 * The difference between a glueless mesh topology and a backplane
6331 * topology lies in whether communication between not directly
6332 * connected nodes goes through intermediary nodes (where programs
6333 * could run), or through backplane controllers. This affects
6334 * placement of programs.
6336 * The type of topology can be discerned with the following tests:
6337 * - If the maximum distance between any nodes is 1 hop, the system
6338 * is directly connected.
6339 * - If for two nodes A and B, located N > 1 hops away from each other,
6340 * there is an intermediary node C, which is < N hops away from both
6341 * nodes A and B, the system is a glueless mesh.
6343 static void init_numa_topology_type(void)
6347 n
= sched_max_numa_distance
;
6350 sched_numa_topology_type
= NUMA_DIRECT
;
6352 for_each_online_node(a
) {
6353 for_each_online_node(b
) {
6354 /* Find two nodes furthest removed from each other. */
6355 if (node_distance(a
, b
) < n
)
6358 /* Is there an intermediary node between a and b? */
6359 for_each_online_node(c
) {
6360 if (node_distance(a
, c
) < n
&&
6361 node_distance(b
, c
) < n
) {
6362 sched_numa_topology_type
=
6368 sched_numa_topology_type
= NUMA_BACKPLANE
;
6374 static void sched_init_numa(void)
6376 int next_distance
, curr_distance
= node_distance(0, 0);
6377 struct sched_domain_topology_level
*tl
;
6381 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6382 if (!sched_domains_numa_distance
)
6386 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6387 * unique distances in the node_distance() table.
6389 * Assumes node_distance(0,j) includes all distances in
6390 * node_distance(i,j) in order to avoid cubic time.
6392 next_distance
= curr_distance
;
6393 for (i
= 0; i
< nr_node_ids
; i
++) {
6394 for (j
= 0; j
< nr_node_ids
; j
++) {
6395 for (k
= 0; k
< nr_node_ids
; k
++) {
6396 int distance
= node_distance(i
, k
);
6398 if (distance
> curr_distance
&&
6399 (distance
< next_distance
||
6400 next_distance
== curr_distance
))
6401 next_distance
= distance
;
6404 * While not a strong assumption it would be nice to know
6405 * about cases where if node A is connected to B, B is not
6406 * equally connected to A.
6408 if (sched_debug() && node_distance(k
, i
) != distance
)
6409 sched_numa_warn("Node-distance not symmetric");
6411 if (sched_debug() && i
&& !find_numa_distance(distance
))
6412 sched_numa_warn("Node-0 not representative");
6414 if (next_distance
!= curr_distance
) {
6415 sched_domains_numa_distance
[level
++] = next_distance
;
6416 sched_domains_numa_levels
= level
;
6417 curr_distance
= next_distance
;
6422 * In case of sched_debug() we verify the above assumption.
6432 * 'level' contains the number of unique distances, excluding the
6433 * identity distance node_distance(i,i).
6435 * The sched_domains_numa_distance[] array includes the actual distance
6440 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6441 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6442 * the array will contain less then 'level' members. This could be
6443 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6444 * in other functions.
6446 * We reset it to 'level' at the end of this function.
6448 sched_domains_numa_levels
= 0;
6450 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6451 if (!sched_domains_numa_masks
)
6455 * Now for each level, construct a mask per node which contains all
6456 * cpus of nodes that are that many hops away from us.
6458 for (i
= 0; i
< level
; i
++) {
6459 sched_domains_numa_masks
[i
] =
6460 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6461 if (!sched_domains_numa_masks
[i
])
6464 for (j
= 0; j
< nr_node_ids
; j
++) {
6465 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6469 sched_domains_numa_masks
[i
][j
] = mask
;
6471 for (k
= 0; k
< nr_node_ids
; k
++) {
6472 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6475 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6480 /* Compute default topology size */
6481 for (i
= 0; sched_domain_topology
[i
].mask
; i
++);
6483 tl
= kzalloc((i
+ level
+ 1) *
6484 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6489 * Copy the default topology bits..
6491 for (i
= 0; sched_domain_topology
[i
].mask
; i
++)
6492 tl
[i
] = sched_domain_topology
[i
];
6495 * .. and append 'j' levels of NUMA goodness.
6497 for (j
= 0; j
< level
; i
++, j
++) {
6498 tl
[i
] = (struct sched_domain_topology_level
){
6499 .mask
= sd_numa_mask
,
6500 .sd_flags
= cpu_numa_flags
,
6501 .flags
= SDTL_OVERLAP
,
6507 sched_domain_topology
= tl
;
6509 sched_domains_numa_levels
= level
;
6510 sched_max_numa_distance
= sched_domains_numa_distance
[level
- 1];
6512 init_numa_topology_type();
6515 static void sched_domains_numa_masks_set(int cpu
)
6518 int node
= cpu_to_node(cpu
);
6520 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6521 for (j
= 0; j
< nr_node_ids
; j
++) {
6522 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6523 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6528 static void sched_domains_numa_masks_clear(int cpu
)
6531 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6532 for (j
= 0; j
< nr_node_ids
; j
++)
6533 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6538 * Update sched_domains_numa_masks[level][node] array when new cpus
6541 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6542 unsigned long action
,
6545 int cpu
= (long)hcpu
;
6547 switch (action
& ~CPU_TASKS_FROZEN
) {
6549 sched_domains_numa_masks_set(cpu
);
6553 sched_domains_numa_masks_clear(cpu
);
6563 static inline void sched_init_numa(void)
6567 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6568 unsigned long action
,
6573 #endif /* CONFIG_NUMA */
6575 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6577 struct sched_domain_topology_level
*tl
;
6580 for_each_sd_topology(tl
) {
6581 struct sd_data
*sdd
= &tl
->data
;
6583 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6587 sdd
->sg
= alloc_percpu(struct sched_group
*);
6591 sdd
->sgc
= alloc_percpu(struct sched_group_capacity
*);
6595 for_each_cpu(j
, cpu_map
) {
6596 struct sched_domain
*sd
;
6597 struct sched_group
*sg
;
6598 struct sched_group_capacity
*sgc
;
6600 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6601 GFP_KERNEL
, cpu_to_node(j
));
6605 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6607 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6608 GFP_KERNEL
, cpu_to_node(j
));
6614 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6616 sgc
= kzalloc_node(sizeof(struct sched_group_capacity
) + cpumask_size(),
6617 GFP_KERNEL
, cpu_to_node(j
));
6621 *per_cpu_ptr(sdd
->sgc
, j
) = sgc
;
6628 static void __sdt_free(const struct cpumask
*cpu_map
)
6630 struct sched_domain_topology_level
*tl
;
6633 for_each_sd_topology(tl
) {
6634 struct sd_data
*sdd
= &tl
->data
;
6636 for_each_cpu(j
, cpu_map
) {
6637 struct sched_domain
*sd
;
6640 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6641 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6642 free_sched_groups(sd
->groups
, 0);
6643 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6647 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6649 kfree(*per_cpu_ptr(sdd
->sgc
, j
));
6651 free_percpu(sdd
->sd
);
6653 free_percpu(sdd
->sg
);
6655 free_percpu(sdd
->sgc
);
6660 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6661 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6662 struct sched_domain
*child
, int cpu
)
6664 struct sched_domain
*sd
= sd_init(tl
, cpu
);
6668 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6670 sd
->level
= child
->level
+ 1;
6671 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6675 if (!cpumask_subset(sched_domain_span(child
),
6676 sched_domain_span(sd
))) {
6677 pr_err("BUG: arch topology borken\n");
6678 #ifdef CONFIG_SCHED_DEBUG
6679 pr_err(" the %s domain not a subset of the %s domain\n",
6680 child
->name
, sd
->name
);
6682 /* Fixup, ensure @sd has at least @child cpus. */
6683 cpumask_or(sched_domain_span(sd
),
6684 sched_domain_span(sd
),
6685 sched_domain_span(child
));
6689 set_domain_attribute(sd
, attr
);
6695 * Build sched domains for a given set of cpus and attach the sched domains
6696 * to the individual cpus
6698 static int build_sched_domains(const struct cpumask
*cpu_map
,
6699 struct sched_domain_attr
*attr
)
6701 enum s_alloc alloc_state
;
6702 struct sched_domain
*sd
;
6704 int i
, ret
= -ENOMEM
;
6706 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6707 if (alloc_state
!= sa_rootdomain
)
6710 /* Set up domains for cpus specified by the cpu_map. */
6711 for_each_cpu(i
, cpu_map
) {
6712 struct sched_domain_topology_level
*tl
;
6715 for_each_sd_topology(tl
) {
6716 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6717 if (tl
== sched_domain_topology
)
6718 *per_cpu_ptr(d
.sd
, i
) = sd
;
6719 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6720 sd
->flags
|= SD_OVERLAP
;
6721 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6726 /* Build the groups for the domains */
6727 for_each_cpu(i
, cpu_map
) {
6728 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6729 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6730 if (sd
->flags
& SD_OVERLAP
) {
6731 if (build_overlap_sched_groups(sd
, i
))
6734 if (build_sched_groups(sd
, i
))
6740 /* Calculate CPU capacity for physical packages and nodes */
6741 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6742 if (!cpumask_test_cpu(i
, cpu_map
))
6745 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6746 claim_allocations(i
, sd
);
6747 init_sched_groups_capacity(i
, sd
);
6751 /* Attach the domains */
6753 for_each_cpu(i
, cpu_map
) {
6754 sd
= *per_cpu_ptr(d
.sd
, i
);
6755 cpu_attach_domain(sd
, d
.rd
, i
);
6761 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6765 static cpumask_var_t
*doms_cur
; /* current sched domains */
6766 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6767 static struct sched_domain_attr
*dattr_cur
;
6768 /* attribues of custom domains in 'doms_cur' */
6771 * Special case: If a kmalloc of a doms_cur partition (array of
6772 * cpumask) fails, then fallback to a single sched domain,
6773 * as determined by the single cpumask fallback_doms.
6775 static cpumask_var_t fallback_doms
;
6778 * arch_update_cpu_topology lets virtualized architectures update the
6779 * cpu core maps. It is supposed to return 1 if the topology changed
6780 * or 0 if it stayed the same.
6782 int __weak
arch_update_cpu_topology(void)
6787 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6790 cpumask_var_t
*doms
;
6792 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6795 for (i
= 0; i
< ndoms
; i
++) {
6796 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6797 free_sched_domains(doms
, i
);
6804 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6807 for (i
= 0; i
< ndoms
; i
++)
6808 free_cpumask_var(doms
[i
]);
6813 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6814 * For now this just excludes isolated cpus, but could be used to
6815 * exclude other special cases in the future.
6817 static int init_sched_domains(const struct cpumask
*cpu_map
)
6821 arch_update_cpu_topology();
6823 doms_cur
= alloc_sched_domains(ndoms_cur
);
6825 doms_cur
= &fallback_doms
;
6826 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6827 err
= build_sched_domains(doms_cur
[0], NULL
);
6828 register_sched_domain_sysctl();
6834 * Detach sched domains from a group of cpus specified in cpu_map
6835 * These cpus will now be attached to the NULL domain
6837 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6842 for_each_cpu(i
, cpu_map
)
6843 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6847 /* handle null as "default" */
6848 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6849 struct sched_domain_attr
*new, int idx_new
)
6851 struct sched_domain_attr tmp
;
6858 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6859 new ? (new + idx_new
) : &tmp
,
6860 sizeof(struct sched_domain_attr
));
6864 * Partition sched domains as specified by the 'ndoms_new'
6865 * cpumasks in the array doms_new[] of cpumasks. This compares
6866 * doms_new[] to the current sched domain partitioning, doms_cur[].
6867 * It destroys each deleted domain and builds each new domain.
6869 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6870 * The masks don't intersect (don't overlap.) We should setup one
6871 * sched domain for each mask. CPUs not in any of the cpumasks will
6872 * not be load balanced. If the same cpumask appears both in the
6873 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6876 * The passed in 'doms_new' should be allocated using
6877 * alloc_sched_domains. This routine takes ownership of it and will
6878 * free_sched_domains it when done with it. If the caller failed the
6879 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6880 * and partition_sched_domains() will fallback to the single partition
6881 * 'fallback_doms', it also forces the domains to be rebuilt.
6883 * If doms_new == NULL it will be replaced with cpu_online_mask.
6884 * ndoms_new == 0 is a special case for destroying existing domains,
6885 * and it will not create the default domain.
6887 * Call with hotplug lock held
6889 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6890 struct sched_domain_attr
*dattr_new
)
6895 mutex_lock(&sched_domains_mutex
);
6897 /* always unregister in case we don't destroy any domains */
6898 unregister_sched_domain_sysctl();
6900 /* Let architecture update cpu core mappings. */
6901 new_topology
= arch_update_cpu_topology();
6903 n
= doms_new
? ndoms_new
: 0;
6905 /* Destroy deleted domains */
6906 for (i
= 0; i
< ndoms_cur
; i
++) {
6907 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6908 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6909 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6912 /* no match - a current sched domain not in new doms_new[] */
6913 detach_destroy_domains(doms_cur
[i
]);
6919 if (doms_new
== NULL
) {
6921 doms_new
= &fallback_doms
;
6922 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6923 WARN_ON_ONCE(dattr_new
);
6926 /* Build new domains */
6927 for (i
= 0; i
< ndoms_new
; i
++) {
6928 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6929 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6930 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6933 /* no match - add a new doms_new */
6934 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6939 /* Remember the new sched domains */
6940 if (doms_cur
!= &fallback_doms
)
6941 free_sched_domains(doms_cur
, ndoms_cur
);
6942 kfree(dattr_cur
); /* kfree(NULL) is safe */
6943 doms_cur
= doms_new
;
6944 dattr_cur
= dattr_new
;
6945 ndoms_cur
= ndoms_new
;
6947 register_sched_domain_sysctl();
6949 mutex_unlock(&sched_domains_mutex
);
6952 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
6955 * Update cpusets according to cpu_active mask. If cpusets are
6956 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
6957 * around partition_sched_domains().
6959 * If we come here as part of a suspend/resume, don't touch cpusets because we
6960 * want to restore it back to its original state upon resume anyway.
6962 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
6966 case CPU_ONLINE_FROZEN
:
6967 case CPU_DOWN_FAILED_FROZEN
:
6970 * num_cpus_frozen tracks how many CPUs are involved in suspend
6971 * resume sequence. As long as this is not the last online
6972 * operation in the resume sequence, just build a single sched
6973 * domain, ignoring cpusets.
6976 if (likely(num_cpus_frozen
)) {
6977 partition_sched_domains(1, NULL
, NULL
);
6982 * This is the last CPU online operation. So fall through and
6983 * restore the original sched domains by considering the
6984 * cpuset configurations.
6988 cpuset_update_active_cpus(true);
6996 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
6999 unsigned long flags
;
7000 long cpu
= (long)hcpu
;
7006 case CPU_DOWN_PREPARE
:
7007 rcu_read_lock_sched();
7008 dl_b
= dl_bw_of(cpu
);
7010 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7011 cpus
= dl_bw_cpus(cpu
);
7012 overflow
= __dl_overflow(dl_b
, cpus
, 0, 0);
7013 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7015 rcu_read_unlock_sched();
7018 return notifier_from_errno(-EBUSY
);
7019 cpuset_update_active_cpus(false);
7021 case CPU_DOWN_PREPARE_FROZEN
:
7023 partition_sched_domains(1, NULL
, NULL
);
7031 void __init
sched_init_smp(void)
7033 cpumask_var_t non_isolated_cpus
;
7035 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7036 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7041 * There's no userspace yet to cause hotplug operations; hence all the
7042 * cpu masks are stable and all blatant races in the below code cannot
7045 mutex_lock(&sched_domains_mutex
);
7046 init_sched_domains(cpu_active_mask
);
7047 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7048 if (cpumask_empty(non_isolated_cpus
))
7049 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7050 mutex_unlock(&sched_domains_mutex
);
7052 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
7053 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7054 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7058 /* Move init over to a non-isolated CPU */
7059 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7061 sched_init_granularity();
7062 free_cpumask_var(non_isolated_cpus
);
7064 init_sched_rt_class();
7065 init_sched_dl_class();
7068 void __init
sched_init_smp(void)
7070 sched_init_granularity();
7072 #endif /* CONFIG_SMP */
7074 const_debug
unsigned int sysctl_timer_migration
= 1;
7076 int in_sched_functions(unsigned long addr
)
7078 return in_lock_functions(addr
) ||
7079 (addr
>= (unsigned long)__sched_text_start
7080 && addr
< (unsigned long)__sched_text_end
);
7083 #ifdef CONFIG_CGROUP_SCHED
7085 * Default task group.
7086 * Every task in system belongs to this group at bootup.
7088 struct task_group root_task_group
;
7089 LIST_HEAD(task_groups
);
7092 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
7094 void __init
sched_init(void)
7097 unsigned long alloc_size
= 0, ptr
;
7099 #ifdef CONFIG_FAIR_GROUP_SCHED
7100 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7102 #ifdef CONFIG_RT_GROUP_SCHED
7103 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7106 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
7108 #ifdef CONFIG_FAIR_GROUP_SCHED
7109 root_task_group
.se
= (struct sched_entity
**)ptr
;
7110 ptr
+= nr_cpu_ids
* sizeof(void **);
7112 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7113 ptr
+= nr_cpu_ids
* sizeof(void **);
7115 #endif /* CONFIG_FAIR_GROUP_SCHED */
7116 #ifdef CONFIG_RT_GROUP_SCHED
7117 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7118 ptr
+= nr_cpu_ids
* sizeof(void **);
7120 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7121 ptr
+= nr_cpu_ids
* sizeof(void **);
7123 #endif /* CONFIG_RT_GROUP_SCHED */
7125 #ifdef CONFIG_CPUMASK_OFFSTACK
7126 for_each_possible_cpu(i
) {
7127 per_cpu(load_balance_mask
, i
) = (cpumask_var_t
)kzalloc_node(
7128 cpumask_size(), GFP_KERNEL
, cpu_to_node(i
));
7130 #endif /* CONFIG_CPUMASK_OFFSTACK */
7132 init_rt_bandwidth(&def_rt_bandwidth
,
7133 global_rt_period(), global_rt_runtime());
7134 init_dl_bandwidth(&def_dl_bandwidth
,
7135 global_rt_period(), global_rt_runtime());
7138 init_defrootdomain();
7141 #ifdef CONFIG_RT_GROUP_SCHED
7142 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7143 global_rt_period(), global_rt_runtime());
7144 #endif /* CONFIG_RT_GROUP_SCHED */
7146 #ifdef CONFIG_CGROUP_SCHED
7147 list_add(&root_task_group
.list
, &task_groups
);
7148 INIT_LIST_HEAD(&root_task_group
.children
);
7149 INIT_LIST_HEAD(&root_task_group
.siblings
);
7150 autogroup_init(&init_task
);
7152 #endif /* CONFIG_CGROUP_SCHED */
7154 for_each_possible_cpu(i
) {
7158 raw_spin_lock_init(&rq
->lock
);
7160 rq
->calc_load_active
= 0;
7161 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
7162 init_cfs_rq(&rq
->cfs
);
7163 init_rt_rq(&rq
->rt
);
7164 init_dl_rq(&rq
->dl
);
7165 #ifdef CONFIG_FAIR_GROUP_SCHED
7166 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
7167 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7169 * How much cpu bandwidth does root_task_group get?
7171 * In case of task-groups formed thr' the cgroup filesystem, it
7172 * gets 100% of the cpu resources in the system. This overall
7173 * system cpu resource is divided among the tasks of
7174 * root_task_group and its child task-groups in a fair manner,
7175 * based on each entity's (task or task-group's) weight
7176 * (se->load.weight).
7178 * In other words, if root_task_group has 10 tasks of weight
7179 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7180 * then A0's share of the cpu resource is:
7182 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7184 * We achieve this by letting root_task_group's tasks sit
7185 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7187 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
7188 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
7189 #endif /* CONFIG_FAIR_GROUP_SCHED */
7191 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7192 #ifdef CONFIG_RT_GROUP_SCHED
7193 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
7196 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7197 rq
->cpu_load
[j
] = 0;
7199 rq
->last_load_update_tick
= jiffies
;
7204 rq
->cpu_capacity
= rq
->cpu_capacity_orig
= SCHED_CAPACITY_SCALE
;
7205 rq
->post_schedule
= 0;
7206 rq
->active_balance
= 0;
7207 rq
->next_balance
= jiffies
;
7212 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7213 rq
->max_idle_balance_cost
= sysctl_sched_migration_cost
;
7215 INIT_LIST_HEAD(&rq
->cfs_tasks
);
7217 rq_attach_root(rq
, &def_root_domain
);
7218 #ifdef CONFIG_NO_HZ_COMMON
7221 #ifdef CONFIG_NO_HZ_FULL
7222 rq
->last_sched_tick
= 0;
7226 atomic_set(&rq
->nr_iowait
, 0);
7229 set_load_weight(&init_task
);
7231 #ifdef CONFIG_PREEMPT_NOTIFIERS
7232 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7236 * The boot idle thread does lazy MMU switching as well:
7238 atomic_inc(&init_mm
.mm_count
);
7239 enter_lazy_tlb(&init_mm
, current
);
7242 * During early bootup we pretend to be a normal task:
7244 current
->sched_class
= &fair_sched_class
;
7247 * Make us the idle thread. Technically, schedule() should not be
7248 * called from this thread, however somewhere below it might be,
7249 * but because we are the idle thread, we just pick up running again
7250 * when this runqueue becomes "idle".
7252 init_idle(current
, smp_processor_id());
7254 calc_load_update
= jiffies
+ LOAD_FREQ
;
7257 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
7258 /* May be allocated at isolcpus cmdline parse time */
7259 if (cpu_isolated_map
== NULL
)
7260 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7261 idle_thread_set_boot_cpu();
7262 set_cpu_rq_start_time();
7264 init_sched_fair_class();
7266 scheduler_running
= 1;
7269 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7270 static inline int preempt_count_equals(int preempt_offset
)
7272 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7274 return (nested
== preempt_offset
);
7277 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7280 * Blocking primitives will set (and therefore destroy) current->state,
7281 * since we will exit with TASK_RUNNING make sure we enter with it,
7282 * otherwise we will destroy state.
7284 WARN_ONCE(current
->state
!= TASK_RUNNING
&& current
->task_state_change
,
7285 "do not call blocking ops when !TASK_RUNNING; "
7286 "state=%lx set at [<%p>] %pS\n",
7288 (void *)current
->task_state_change
,
7289 (void *)current
->task_state_change
);
7291 ___might_sleep(file
, line
, preempt_offset
);
7293 EXPORT_SYMBOL(__might_sleep
);
7295 void ___might_sleep(const char *file
, int line
, int preempt_offset
)
7297 static unsigned long prev_jiffy
; /* ratelimiting */
7299 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7300 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled() &&
7301 !is_idle_task(current
)) ||
7302 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7304 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7306 prev_jiffy
= jiffies
;
7309 "BUG: sleeping function called from invalid context at %s:%d\n",
7312 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7313 in_atomic(), irqs_disabled(),
7314 current
->pid
, current
->comm
);
7316 if (task_stack_end_corrupted(current
))
7317 printk(KERN_EMERG
"Thread overran stack, or stack corrupted\n");
7319 debug_show_held_locks(current
);
7320 if (irqs_disabled())
7321 print_irqtrace_events(current
);
7322 #ifdef CONFIG_DEBUG_PREEMPT
7323 if (!preempt_count_equals(preempt_offset
)) {
7324 pr_err("Preemption disabled at:");
7325 print_ip_sym(current
->preempt_disable_ip
);
7331 EXPORT_SYMBOL(___might_sleep
);
7334 #ifdef CONFIG_MAGIC_SYSRQ
7335 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7337 const struct sched_class
*prev_class
= p
->sched_class
;
7338 struct sched_attr attr
= {
7339 .sched_policy
= SCHED_NORMAL
,
7341 int old_prio
= p
->prio
;
7344 queued
= task_on_rq_queued(p
);
7346 dequeue_task(rq
, p
, 0);
7347 __setscheduler(rq
, p
, &attr
, false);
7349 enqueue_task(rq
, p
, 0);
7353 check_class_changed(rq
, p
, prev_class
, old_prio
);
7356 void normalize_rt_tasks(void)
7358 struct task_struct
*g
, *p
;
7359 unsigned long flags
;
7362 read_lock(&tasklist_lock
);
7363 for_each_process_thread(g
, p
) {
7365 * Only normalize user tasks:
7367 if (p
->flags
& PF_KTHREAD
)
7370 p
->se
.exec_start
= 0;
7371 #ifdef CONFIG_SCHEDSTATS
7372 p
->se
.statistics
.wait_start
= 0;
7373 p
->se
.statistics
.sleep_start
= 0;
7374 p
->se
.statistics
.block_start
= 0;
7377 if (!dl_task(p
) && !rt_task(p
)) {
7379 * Renice negative nice level userspace
7382 if (task_nice(p
) < 0)
7383 set_user_nice(p
, 0);
7387 rq
= task_rq_lock(p
, &flags
);
7388 normalize_task(rq
, p
);
7389 task_rq_unlock(rq
, p
, &flags
);
7391 read_unlock(&tasklist_lock
);
7394 #endif /* CONFIG_MAGIC_SYSRQ */
7396 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7398 * These functions are only useful for the IA64 MCA handling, or kdb.
7400 * They can only be called when the whole system has been
7401 * stopped - every CPU needs to be quiescent, and no scheduling
7402 * activity can take place. Using them for anything else would
7403 * be a serious bug, and as a result, they aren't even visible
7404 * under any other configuration.
7408 * curr_task - return the current task for a given cpu.
7409 * @cpu: the processor in question.
7411 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7413 * Return: The current task for @cpu.
7415 struct task_struct
*curr_task(int cpu
)
7417 return cpu_curr(cpu
);
7420 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7424 * set_curr_task - set the current task for a given cpu.
7425 * @cpu: the processor in question.
7426 * @p: the task pointer to set.
7428 * Description: This function must only be used when non-maskable interrupts
7429 * are serviced on a separate stack. It allows the architecture to switch the
7430 * notion of the current task on a cpu in a non-blocking manner. This function
7431 * must be called with all CPU's synchronized, and interrupts disabled, the
7432 * and caller must save the original value of the current task (see
7433 * curr_task() above) and restore that value before reenabling interrupts and
7434 * re-starting the system.
7436 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7438 void set_curr_task(int cpu
, struct task_struct
*p
)
7445 #ifdef CONFIG_CGROUP_SCHED
7446 /* task_group_lock serializes the addition/removal of task groups */
7447 static DEFINE_SPINLOCK(task_group_lock
);
7449 static void free_sched_group(struct task_group
*tg
)
7451 free_fair_sched_group(tg
);
7452 free_rt_sched_group(tg
);
7457 /* allocate runqueue etc for a new task group */
7458 struct task_group
*sched_create_group(struct task_group
*parent
)
7460 struct task_group
*tg
;
7462 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7464 return ERR_PTR(-ENOMEM
);
7466 if (!alloc_fair_sched_group(tg
, parent
))
7469 if (!alloc_rt_sched_group(tg
, parent
))
7475 free_sched_group(tg
);
7476 return ERR_PTR(-ENOMEM
);
7479 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
7481 unsigned long flags
;
7483 spin_lock_irqsave(&task_group_lock
, flags
);
7484 list_add_rcu(&tg
->list
, &task_groups
);
7486 WARN_ON(!parent
); /* root should already exist */
7488 tg
->parent
= parent
;
7489 INIT_LIST_HEAD(&tg
->children
);
7490 list_add_rcu(&tg
->siblings
, &parent
->children
);
7491 spin_unlock_irqrestore(&task_group_lock
, flags
);
7494 /* rcu callback to free various structures associated with a task group */
7495 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7497 /* now it should be safe to free those cfs_rqs */
7498 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7501 /* Destroy runqueue etc associated with a task group */
7502 void sched_destroy_group(struct task_group
*tg
)
7504 /* wait for possible concurrent references to cfs_rqs complete */
7505 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7508 void sched_offline_group(struct task_group
*tg
)
7510 unsigned long flags
;
7513 /* end participation in shares distribution */
7514 for_each_possible_cpu(i
)
7515 unregister_fair_sched_group(tg
, i
);
7517 spin_lock_irqsave(&task_group_lock
, flags
);
7518 list_del_rcu(&tg
->list
);
7519 list_del_rcu(&tg
->siblings
);
7520 spin_unlock_irqrestore(&task_group_lock
, flags
);
7523 /* change task's runqueue when it moves between groups.
7524 * The caller of this function should have put the task in its new group
7525 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7526 * reflect its new group.
7528 void sched_move_task(struct task_struct
*tsk
)
7530 struct task_group
*tg
;
7531 int queued
, running
;
7532 unsigned long flags
;
7535 rq
= task_rq_lock(tsk
, &flags
);
7537 running
= task_current(rq
, tsk
);
7538 queued
= task_on_rq_queued(tsk
);
7541 dequeue_task(rq
, tsk
, 0);
7542 if (unlikely(running
))
7543 put_prev_task(rq
, tsk
);
7546 * All callers are synchronized by task_rq_lock(); we do not use RCU
7547 * which is pointless here. Thus, we pass "true" to task_css_check()
7548 * to prevent lockdep warnings.
7550 tg
= container_of(task_css_check(tsk
, cpu_cgrp_id
, true),
7551 struct task_group
, css
);
7552 tg
= autogroup_task_group(tsk
, tg
);
7553 tsk
->sched_task_group
= tg
;
7555 #ifdef CONFIG_FAIR_GROUP_SCHED
7556 if (tsk
->sched_class
->task_move_group
)
7557 tsk
->sched_class
->task_move_group(tsk
, queued
);
7560 set_task_rq(tsk
, task_cpu(tsk
));
7562 if (unlikely(running
))
7563 tsk
->sched_class
->set_curr_task(rq
);
7565 enqueue_task(rq
, tsk
, 0);
7567 task_rq_unlock(rq
, tsk
, &flags
);
7569 #endif /* CONFIG_CGROUP_SCHED */
7571 #ifdef CONFIG_RT_GROUP_SCHED
7573 * Ensure that the real time constraints are schedulable.
7575 static DEFINE_MUTEX(rt_constraints_mutex
);
7577 /* Must be called with tasklist_lock held */
7578 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7580 struct task_struct
*g
, *p
;
7583 * Autogroups do not have RT tasks; see autogroup_create().
7585 if (task_group_is_autogroup(tg
))
7588 for_each_process_thread(g
, p
) {
7589 if (rt_task(p
) && task_group(p
) == tg
)
7596 struct rt_schedulable_data
{
7597 struct task_group
*tg
;
7602 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7604 struct rt_schedulable_data
*d
= data
;
7605 struct task_group
*child
;
7606 unsigned long total
, sum
= 0;
7607 u64 period
, runtime
;
7609 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7610 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7613 period
= d
->rt_period
;
7614 runtime
= d
->rt_runtime
;
7618 * Cannot have more runtime than the period.
7620 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7624 * Ensure we don't starve existing RT tasks.
7626 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7629 total
= to_ratio(period
, runtime
);
7632 * Nobody can have more than the global setting allows.
7634 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7638 * The sum of our children's runtime should not exceed our own.
7640 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7641 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7642 runtime
= child
->rt_bandwidth
.rt_runtime
;
7644 if (child
== d
->tg
) {
7645 period
= d
->rt_period
;
7646 runtime
= d
->rt_runtime
;
7649 sum
+= to_ratio(period
, runtime
);
7658 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7662 struct rt_schedulable_data data
= {
7664 .rt_period
= period
,
7665 .rt_runtime
= runtime
,
7669 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7675 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7676 u64 rt_period
, u64 rt_runtime
)
7681 * Disallowing the root group RT runtime is BAD, it would disallow the
7682 * kernel creating (and or operating) RT threads.
7684 if (tg
== &root_task_group
&& rt_runtime
== 0)
7687 /* No period doesn't make any sense. */
7691 mutex_lock(&rt_constraints_mutex
);
7692 read_lock(&tasklist_lock
);
7693 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7697 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7698 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7699 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7701 for_each_possible_cpu(i
) {
7702 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7704 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7705 rt_rq
->rt_runtime
= rt_runtime
;
7706 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7708 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7710 read_unlock(&tasklist_lock
);
7711 mutex_unlock(&rt_constraints_mutex
);
7716 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7718 u64 rt_runtime
, rt_period
;
7720 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7721 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7722 if (rt_runtime_us
< 0)
7723 rt_runtime
= RUNTIME_INF
;
7725 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7728 static long sched_group_rt_runtime(struct task_group
*tg
)
7732 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7735 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7736 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7737 return rt_runtime_us
;
7740 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7742 u64 rt_runtime
, rt_period
;
7744 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7745 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7747 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7750 static long sched_group_rt_period(struct task_group
*tg
)
7754 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7755 do_div(rt_period_us
, NSEC_PER_USEC
);
7756 return rt_period_us
;
7758 #endif /* CONFIG_RT_GROUP_SCHED */
7760 #ifdef CONFIG_RT_GROUP_SCHED
7761 static int sched_rt_global_constraints(void)
7765 mutex_lock(&rt_constraints_mutex
);
7766 read_lock(&tasklist_lock
);
7767 ret
= __rt_schedulable(NULL
, 0, 0);
7768 read_unlock(&tasklist_lock
);
7769 mutex_unlock(&rt_constraints_mutex
);
7774 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7776 /* Don't accept realtime tasks when there is no way for them to run */
7777 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7783 #else /* !CONFIG_RT_GROUP_SCHED */
7784 static int sched_rt_global_constraints(void)
7786 unsigned long flags
;
7789 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7790 for_each_possible_cpu(i
) {
7791 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7793 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7794 rt_rq
->rt_runtime
= global_rt_runtime();
7795 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7797 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7801 #endif /* CONFIG_RT_GROUP_SCHED */
7803 static int sched_dl_global_validate(void)
7805 u64 runtime
= global_rt_runtime();
7806 u64 period
= global_rt_period();
7807 u64 new_bw
= to_ratio(period
, runtime
);
7810 unsigned long flags
;
7813 * Here we want to check the bandwidth not being set to some
7814 * value smaller than the currently allocated bandwidth in
7815 * any of the root_domains.
7817 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7818 * cycling on root_domains... Discussion on different/better
7819 * solutions is welcome!
7821 for_each_possible_cpu(cpu
) {
7822 rcu_read_lock_sched();
7823 dl_b
= dl_bw_of(cpu
);
7825 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7826 if (new_bw
< dl_b
->total_bw
)
7828 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7830 rcu_read_unlock_sched();
7839 static void sched_dl_do_global(void)
7844 unsigned long flags
;
7846 def_dl_bandwidth
.dl_period
= global_rt_period();
7847 def_dl_bandwidth
.dl_runtime
= global_rt_runtime();
7849 if (global_rt_runtime() != RUNTIME_INF
)
7850 new_bw
= to_ratio(global_rt_period(), global_rt_runtime());
7853 * FIXME: As above...
7855 for_each_possible_cpu(cpu
) {
7856 rcu_read_lock_sched();
7857 dl_b
= dl_bw_of(cpu
);
7859 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7861 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7863 rcu_read_unlock_sched();
7867 static int sched_rt_global_validate(void)
7869 if (sysctl_sched_rt_period
<= 0)
7872 if ((sysctl_sched_rt_runtime
!= RUNTIME_INF
) &&
7873 (sysctl_sched_rt_runtime
> sysctl_sched_rt_period
))
7879 static void sched_rt_do_global(void)
7881 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7882 def_rt_bandwidth
.rt_period
= ns_to_ktime(global_rt_period());
7885 int sched_rt_handler(struct ctl_table
*table
, int write
,
7886 void __user
*buffer
, size_t *lenp
,
7889 int old_period
, old_runtime
;
7890 static DEFINE_MUTEX(mutex
);
7894 old_period
= sysctl_sched_rt_period
;
7895 old_runtime
= sysctl_sched_rt_runtime
;
7897 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7899 if (!ret
&& write
) {
7900 ret
= sched_rt_global_validate();
7904 ret
= sched_dl_global_validate();
7908 ret
= sched_rt_global_constraints();
7912 sched_rt_do_global();
7913 sched_dl_do_global();
7917 sysctl_sched_rt_period
= old_period
;
7918 sysctl_sched_rt_runtime
= old_runtime
;
7920 mutex_unlock(&mutex
);
7925 int sched_rr_handler(struct ctl_table
*table
, int write
,
7926 void __user
*buffer
, size_t *lenp
,
7930 static DEFINE_MUTEX(mutex
);
7933 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7934 /* make sure that internally we keep jiffies */
7935 /* also, writing zero resets timeslice to default */
7936 if (!ret
&& write
) {
7937 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7938 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7940 mutex_unlock(&mutex
);
7944 #ifdef CONFIG_CGROUP_SCHED
7946 static inline struct task_group
*css_tg(struct cgroup_subsys_state
*css
)
7948 return css
? container_of(css
, struct task_group
, css
) : NULL
;
7951 static struct cgroup_subsys_state
*
7952 cpu_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
7954 struct task_group
*parent
= css_tg(parent_css
);
7955 struct task_group
*tg
;
7958 /* This is early initialization for the top cgroup */
7959 return &root_task_group
.css
;
7962 tg
= sched_create_group(parent
);
7964 return ERR_PTR(-ENOMEM
);
7969 static int cpu_cgroup_css_online(struct cgroup_subsys_state
*css
)
7971 struct task_group
*tg
= css_tg(css
);
7972 struct task_group
*parent
= css_tg(css
->parent
);
7975 sched_online_group(tg
, parent
);
7979 static void cpu_cgroup_css_free(struct cgroup_subsys_state
*css
)
7981 struct task_group
*tg
= css_tg(css
);
7983 sched_destroy_group(tg
);
7986 static void cpu_cgroup_css_offline(struct cgroup_subsys_state
*css
)
7988 struct task_group
*tg
= css_tg(css
);
7990 sched_offline_group(tg
);
7993 static void cpu_cgroup_fork(struct task_struct
*task
)
7995 sched_move_task(task
);
7998 static int cpu_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7999 struct cgroup_taskset
*tset
)
8001 struct task_struct
*task
;
8003 cgroup_taskset_for_each(task
, tset
) {
8004 #ifdef CONFIG_RT_GROUP_SCHED
8005 if (!sched_rt_can_attach(css_tg(css
), task
))
8008 /* We don't support RT-tasks being in separate groups */
8009 if (task
->sched_class
!= &fair_sched_class
)
8016 static void cpu_cgroup_attach(struct cgroup_subsys_state
*css
,
8017 struct cgroup_taskset
*tset
)
8019 struct task_struct
*task
;
8021 cgroup_taskset_for_each(task
, tset
)
8022 sched_move_task(task
);
8025 static void cpu_cgroup_exit(struct cgroup_subsys_state
*css
,
8026 struct cgroup_subsys_state
*old_css
,
8027 struct task_struct
*task
)
8030 * cgroup_exit() is called in the copy_process() failure path.
8031 * Ignore this case since the task hasn't ran yet, this avoids
8032 * trying to poke a half freed task state from generic code.
8034 if (!(task
->flags
& PF_EXITING
))
8037 sched_move_task(task
);
8040 #ifdef CONFIG_FAIR_GROUP_SCHED
8041 static int cpu_shares_write_u64(struct cgroup_subsys_state
*css
,
8042 struct cftype
*cftype
, u64 shareval
)
8044 return sched_group_set_shares(css_tg(css
), scale_load(shareval
));
8047 static u64
cpu_shares_read_u64(struct cgroup_subsys_state
*css
,
8050 struct task_group
*tg
= css_tg(css
);
8052 return (u64
) scale_load_down(tg
->shares
);
8055 #ifdef CONFIG_CFS_BANDWIDTH
8056 static DEFINE_MUTEX(cfs_constraints_mutex
);
8058 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
8059 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
8061 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
8063 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
8065 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
8066 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8068 if (tg
== &root_task_group
)
8072 * Ensure we have at some amount of bandwidth every period. This is
8073 * to prevent reaching a state of large arrears when throttled via
8074 * entity_tick() resulting in prolonged exit starvation.
8076 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
8080 * Likewise, bound things on the otherside by preventing insane quota
8081 * periods. This also allows us to normalize in computing quota
8084 if (period
> max_cfs_quota_period
)
8088 * Prevent race between setting of cfs_rq->runtime_enabled and
8089 * unthrottle_offline_cfs_rqs().
8092 mutex_lock(&cfs_constraints_mutex
);
8093 ret
= __cfs_schedulable(tg
, period
, quota
);
8097 runtime_enabled
= quota
!= RUNTIME_INF
;
8098 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
8100 * If we need to toggle cfs_bandwidth_used, off->on must occur
8101 * before making related changes, and on->off must occur afterwards
8103 if (runtime_enabled
&& !runtime_was_enabled
)
8104 cfs_bandwidth_usage_inc();
8105 raw_spin_lock_irq(&cfs_b
->lock
);
8106 cfs_b
->period
= ns_to_ktime(period
);
8107 cfs_b
->quota
= quota
;
8109 __refill_cfs_bandwidth_runtime(cfs_b
);
8110 /* restart the period timer (if active) to handle new period expiry */
8111 if (runtime_enabled
&& cfs_b
->timer_active
) {
8112 /* force a reprogram */
8113 __start_cfs_bandwidth(cfs_b
, true);
8115 raw_spin_unlock_irq(&cfs_b
->lock
);
8117 for_each_online_cpu(i
) {
8118 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
8119 struct rq
*rq
= cfs_rq
->rq
;
8121 raw_spin_lock_irq(&rq
->lock
);
8122 cfs_rq
->runtime_enabled
= runtime_enabled
;
8123 cfs_rq
->runtime_remaining
= 0;
8125 if (cfs_rq
->throttled
)
8126 unthrottle_cfs_rq(cfs_rq
);
8127 raw_spin_unlock_irq(&rq
->lock
);
8129 if (runtime_was_enabled
&& !runtime_enabled
)
8130 cfs_bandwidth_usage_dec();
8132 mutex_unlock(&cfs_constraints_mutex
);
8138 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
8142 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
8143 if (cfs_quota_us
< 0)
8144 quota
= RUNTIME_INF
;
8146 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
8148 return tg_set_cfs_bandwidth(tg
, period
, quota
);
8151 long tg_get_cfs_quota(struct task_group
*tg
)
8155 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
8158 quota_us
= tg
->cfs_bandwidth
.quota
;
8159 do_div(quota_us
, NSEC_PER_USEC
);
8164 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
8168 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
8169 quota
= tg
->cfs_bandwidth
.quota
;
8171 return tg_set_cfs_bandwidth(tg
, period
, quota
);
8174 long tg_get_cfs_period(struct task_group
*tg
)
8178 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
8179 do_div(cfs_period_us
, NSEC_PER_USEC
);
8181 return cfs_period_us
;
8184 static s64
cpu_cfs_quota_read_s64(struct cgroup_subsys_state
*css
,
8187 return tg_get_cfs_quota(css_tg(css
));
8190 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state
*css
,
8191 struct cftype
*cftype
, s64 cfs_quota_us
)
8193 return tg_set_cfs_quota(css_tg(css
), cfs_quota_us
);
8196 static u64
cpu_cfs_period_read_u64(struct cgroup_subsys_state
*css
,
8199 return tg_get_cfs_period(css_tg(css
));
8202 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state
*css
,
8203 struct cftype
*cftype
, u64 cfs_period_us
)
8205 return tg_set_cfs_period(css_tg(css
), cfs_period_us
);
8208 struct cfs_schedulable_data
{
8209 struct task_group
*tg
;
8214 * normalize group quota/period to be quota/max_period
8215 * note: units are usecs
8217 static u64
normalize_cfs_quota(struct task_group
*tg
,
8218 struct cfs_schedulable_data
*d
)
8226 period
= tg_get_cfs_period(tg
);
8227 quota
= tg_get_cfs_quota(tg
);
8230 /* note: these should typically be equivalent */
8231 if (quota
== RUNTIME_INF
|| quota
== -1)
8234 return to_ratio(period
, quota
);
8237 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
8239 struct cfs_schedulable_data
*d
= data
;
8240 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8241 s64 quota
= 0, parent_quota
= -1;
8244 quota
= RUNTIME_INF
;
8246 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
8248 quota
= normalize_cfs_quota(tg
, d
);
8249 parent_quota
= parent_b
->hierarchical_quota
;
8252 * ensure max(child_quota) <= parent_quota, inherit when no
8255 if (quota
== RUNTIME_INF
)
8256 quota
= parent_quota
;
8257 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
8260 cfs_b
->hierarchical_quota
= quota
;
8265 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
8268 struct cfs_schedulable_data data
= {
8274 if (quota
!= RUNTIME_INF
) {
8275 do_div(data
.period
, NSEC_PER_USEC
);
8276 do_div(data
.quota
, NSEC_PER_USEC
);
8280 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
8286 static int cpu_stats_show(struct seq_file
*sf
, void *v
)
8288 struct task_group
*tg
= css_tg(seq_css(sf
));
8289 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8291 seq_printf(sf
, "nr_periods %d\n", cfs_b
->nr_periods
);
8292 seq_printf(sf
, "nr_throttled %d\n", cfs_b
->nr_throttled
);
8293 seq_printf(sf
, "throttled_time %llu\n", cfs_b
->throttled_time
);
8297 #endif /* CONFIG_CFS_BANDWIDTH */
8298 #endif /* CONFIG_FAIR_GROUP_SCHED */
8300 #ifdef CONFIG_RT_GROUP_SCHED
8301 static int cpu_rt_runtime_write(struct cgroup_subsys_state
*css
,
8302 struct cftype
*cft
, s64 val
)
8304 return sched_group_set_rt_runtime(css_tg(css
), val
);
8307 static s64
cpu_rt_runtime_read(struct cgroup_subsys_state
*css
,
8310 return sched_group_rt_runtime(css_tg(css
));
8313 static int cpu_rt_period_write_uint(struct cgroup_subsys_state
*css
,
8314 struct cftype
*cftype
, u64 rt_period_us
)
8316 return sched_group_set_rt_period(css_tg(css
), rt_period_us
);
8319 static u64
cpu_rt_period_read_uint(struct cgroup_subsys_state
*css
,
8322 return sched_group_rt_period(css_tg(css
));
8324 #endif /* CONFIG_RT_GROUP_SCHED */
8326 static struct cftype cpu_files
[] = {
8327 #ifdef CONFIG_FAIR_GROUP_SCHED
8330 .read_u64
= cpu_shares_read_u64
,
8331 .write_u64
= cpu_shares_write_u64
,
8334 #ifdef CONFIG_CFS_BANDWIDTH
8336 .name
= "cfs_quota_us",
8337 .read_s64
= cpu_cfs_quota_read_s64
,
8338 .write_s64
= cpu_cfs_quota_write_s64
,
8341 .name
= "cfs_period_us",
8342 .read_u64
= cpu_cfs_period_read_u64
,
8343 .write_u64
= cpu_cfs_period_write_u64
,
8347 .seq_show
= cpu_stats_show
,
8350 #ifdef CONFIG_RT_GROUP_SCHED
8352 .name
= "rt_runtime_us",
8353 .read_s64
= cpu_rt_runtime_read
,
8354 .write_s64
= cpu_rt_runtime_write
,
8357 .name
= "rt_period_us",
8358 .read_u64
= cpu_rt_period_read_uint
,
8359 .write_u64
= cpu_rt_period_write_uint
,
8365 struct cgroup_subsys cpu_cgrp_subsys
= {
8366 .css_alloc
= cpu_cgroup_css_alloc
,
8367 .css_free
= cpu_cgroup_css_free
,
8368 .css_online
= cpu_cgroup_css_online
,
8369 .css_offline
= cpu_cgroup_css_offline
,
8370 .fork
= cpu_cgroup_fork
,
8371 .can_attach
= cpu_cgroup_can_attach
,
8372 .attach
= cpu_cgroup_attach
,
8373 .exit
= cpu_cgroup_exit
,
8374 .legacy_cftypes
= cpu_files
,
8378 #endif /* CONFIG_CGROUP_SCHED */
8380 void dump_cpu_task(int cpu
)
8382 pr_info("Task dump for CPU %d:\n", cpu
);
8383 sched_show_task(cpu_curr(cpu
));