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 DEFINE_MUTEX(sched_domains_mutex
);
94 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
96 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
98 void update_rq_clock(struct rq
*rq
)
102 lockdep_assert_held(&rq
->lock
);
104 if (rq
->clock_skip_update
& RQCF_ACT_SKIP
)
107 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
111 update_rq_clock_task(rq
, delta
);
115 * Debugging: various feature bits
118 #define SCHED_FEAT(name, enabled) \
119 (1UL << __SCHED_FEAT_##name) * enabled |
121 const_debug
unsigned int sysctl_sched_features
=
122 #include "features.h"
127 #ifdef CONFIG_SCHED_DEBUG
128 #define SCHED_FEAT(name, enabled) \
131 static const char * const sched_feat_names
[] = {
132 #include "features.h"
137 static int sched_feat_show(struct seq_file
*m
, void *v
)
141 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
142 if (!(sysctl_sched_features
& (1UL << i
)))
144 seq_printf(m
, "%s ", sched_feat_names
[i
]);
151 #ifdef HAVE_JUMP_LABEL
153 #define jump_label_key__true STATIC_KEY_INIT_TRUE
154 #define jump_label_key__false STATIC_KEY_INIT_FALSE
156 #define SCHED_FEAT(name, enabled) \
157 jump_label_key__##enabled ,
159 struct static_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
160 #include "features.h"
165 static void sched_feat_disable(int i
)
167 static_key_disable(&sched_feat_keys
[i
]);
170 static void sched_feat_enable(int i
)
172 static_key_enable(&sched_feat_keys
[i
]);
175 static void sched_feat_disable(int i
) { };
176 static void sched_feat_enable(int i
) { };
177 #endif /* HAVE_JUMP_LABEL */
179 static int sched_feat_set(char *cmp
)
184 if (strncmp(cmp
, "NO_", 3) == 0) {
189 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
190 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
192 sysctl_sched_features
&= ~(1UL << i
);
193 sched_feat_disable(i
);
195 sysctl_sched_features
|= (1UL << i
);
196 sched_feat_enable(i
);
206 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
207 size_t cnt
, loff_t
*ppos
)
217 if (copy_from_user(&buf
, ubuf
, cnt
))
223 /* Ensure the static_key remains in a consistent state */
224 inode
= file_inode(filp
);
225 mutex_lock(&inode
->i_mutex
);
226 i
= sched_feat_set(cmp
);
227 mutex_unlock(&inode
->i_mutex
);
228 if (i
== __SCHED_FEAT_NR
)
236 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
238 return single_open(filp
, sched_feat_show
, NULL
);
241 static const struct file_operations sched_feat_fops
= {
242 .open
= sched_feat_open
,
243 .write
= sched_feat_write
,
246 .release
= single_release
,
249 static __init
int sched_init_debug(void)
251 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
256 late_initcall(sched_init_debug
);
257 #endif /* CONFIG_SCHED_DEBUG */
260 * Number of tasks to iterate in a single balance run.
261 * Limited because this is done with IRQs disabled.
263 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
266 * period over which we average the RT time consumption, measured
271 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
274 * period over which we measure -rt task cpu usage in us.
277 unsigned int sysctl_sched_rt_period
= 1000000;
279 __read_mostly
int scheduler_running
;
282 * part of the period that we allow rt tasks to run in us.
285 int sysctl_sched_rt_runtime
= 950000;
287 /* cpus with isolated domains */
288 cpumask_var_t cpu_isolated_map
;
291 * this_rq_lock - lock this runqueue and disable interrupts.
293 static struct rq
*this_rq_lock(void)
300 raw_spin_lock(&rq
->lock
);
305 #ifdef CONFIG_SCHED_HRTICK
307 * Use HR-timers to deliver accurate preemption points.
310 static void hrtick_clear(struct rq
*rq
)
312 if (hrtimer_active(&rq
->hrtick_timer
))
313 hrtimer_cancel(&rq
->hrtick_timer
);
317 * High-resolution timer tick.
318 * Runs from hardirq context with interrupts disabled.
320 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
322 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
324 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
326 raw_spin_lock(&rq
->lock
);
328 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
329 raw_spin_unlock(&rq
->lock
);
331 return HRTIMER_NORESTART
;
336 static void __hrtick_restart(struct rq
*rq
)
338 struct hrtimer
*timer
= &rq
->hrtick_timer
;
340 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS_PINNED
);
344 * called from hardirq (IPI) context
346 static void __hrtick_start(void *arg
)
350 raw_spin_lock(&rq
->lock
);
351 __hrtick_restart(rq
);
352 rq
->hrtick_csd_pending
= 0;
353 raw_spin_unlock(&rq
->lock
);
357 * Called to set the hrtick timer state.
359 * called with rq->lock held and irqs disabled
361 void hrtick_start(struct rq
*rq
, u64 delay
)
363 struct hrtimer
*timer
= &rq
->hrtick_timer
;
368 * Don't schedule slices shorter than 10000ns, that just
369 * doesn't make sense and can cause timer DoS.
371 delta
= max_t(s64
, delay
, 10000LL);
372 time
= ktime_add_ns(timer
->base
->get_time(), delta
);
374 hrtimer_set_expires(timer
, time
);
376 if (rq
== this_rq()) {
377 __hrtick_restart(rq
);
378 } else if (!rq
->hrtick_csd_pending
) {
379 smp_call_function_single_async(cpu_of(rq
), &rq
->hrtick_csd
);
380 rq
->hrtick_csd_pending
= 1;
385 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
387 int cpu
= (int)(long)hcpu
;
390 case CPU_UP_CANCELED
:
391 case CPU_UP_CANCELED_FROZEN
:
392 case CPU_DOWN_PREPARE
:
393 case CPU_DOWN_PREPARE_FROZEN
:
395 case CPU_DEAD_FROZEN
:
396 hrtick_clear(cpu_rq(cpu
));
403 static __init
void init_hrtick(void)
405 hotcpu_notifier(hotplug_hrtick
, 0);
409 * Called to set the hrtick timer state.
411 * called with rq->lock held and irqs disabled
413 void hrtick_start(struct rq
*rq
, u64 delay
)
416 * Don't schedule slices shorter than 10000ns, that just
417 * doesn't make sense. Rely on vruntime for fairness.
419 delay
= max_t(u64
, delay
, 10000LL);
420 hrtimer_start(&rq
->hrtick_timer
, ns_to_ktime(delay
),
421 HRTIMER_MODE_REL_PINNED
);
424 static inline void init_hrtick(void)
427 #endif /* CONFIG_SMP */
429 static void init_rq_hrtick(struct rq
*rq
)
432 rq
->hrtick_csd_pending
= 0;
434 rq
->hrtick_csd
.flags
= 0;
435 rq
->hrtick_csd
.func
= __hrtick_start
;
436 rq
->hrtick_csd
.info
= rq
;
439 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
440 rq
->hrtick_timer
.function
= hrtick
;
442 #else /* CONFIG_SCHED_HRTICK */
443 static inline void hrtick_clear(struct rq
*rq
)
447 static inline void init_rq_hrtick(struct rq
*rq
)
451 static inline void init_hrtick(void)
454 #endif /* CONFIG_SCHED_HRTICK */
457 * cmpxchg based fetch_or, macro so it works for different integer types
459 #define fetch_or(ptr, val) \
460 ({ typeof(*(ptr)) __old, __val = *(ptr); \
462 __old = cmpxchg((ptr), __val, __val | (val)); \
463 if (__old == __val) \
470 #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
472 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
473 * this avoids any races wrt polling state changes and thereby avoids
476 static bool set_nr_and_not_polling(struct task_struct
*p
)
478 struct thread_info
*ti
= task_thread_info(p
);
479 return !(fetch_or(&ti
->flags
, _TIF_NEED_RESCHED
) & _TIF_POLLING_NRFLAG
);
483 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
485 * If this returns true, then the idle task promises to call
486 * sched_ttwu_pending() and reschedule soon.
488 static bool set_nr_if_polling(struct task_struct
*p
)
490 struct thread_info
*ti
= task_thread_info(p
);
491 typeof(ti
->flags
) old
, val
= READ_ONCE(ti
->flags
);
494 if (!(val
& _TIF_POLLING_NRFLAG
))
496 if (val
& _TIF_NEED_RESCHED
)
498 old
= cmpxchg(&ti
->flags
, val
, val
| _TIF_NEED_RESCHED
);
507 static bool set_nr_and_not_polling(struct task_struct
*p
)
509 set_tsk_need_resched(p
);
514 static bool set_nr_if_polling(struct task_struct
*p
)
521 void wake_q_add(struct wake_q_head
*head
, struct task_struct
*task
)
523 struct wake_q_node
*node
= &task
->wake_q
;
526 * Atomically grab the task, if ->wake_q is !nil already it means
527 * its already queued (either by us or someone else) and will get the
528 * wakeup due to that.
530 * This cmpxchg() implies a full barrier, which pairs with the write
531 * barrier implied by the wakeup in wake_up_list().
533 if (cmpxchg(&node
->next
, NULL
, WAKE_Q_TAIL
))
536 get_task_struct(task
);
539 * The head is context local, there can be no concurrency.
542 head
->lastp
= &node
->next
;
545 void wake_up_q(struct wake_q_head
*head
)
547 struct wake_q_node
*node
= head
->first
;
549 while (node
!= WAKE_Q_TAIL
) {
550 struct task_struct
*task
;
552 task
= container_of(node
, struct task_struct
, wake_q
);
554 /* task can safely be re-inserted now */
556 task
->wake_q
.next
= NULL
;
559 * wake_up_process() implies a wmb() to pair with the queueing
560 * in wake_q_add() so as not to miss wakeups.
562 wake_up_process(task
);
563 put_task_struct(task
);
568 * resched_curr - mark rq's current task 'to be rescheduled now'.
570 * On UP this means the setting of the need_resched flag, on SMP it
571 * might also involve a cross-CPU call to trigger the scheduler on
574 void resched_curr(struct rq
*rq
)
576 struct task_struct
*curr
= rq
->curr
;
579 lockdep_assert_held(&rq
->lock
);
581 if (test_tsk_need_resched(curr
))
586 if (cpu
== smp_processor_id()) {
587 set_tsk_need_resched(curr
);
588 set_preempt_need_resched();
592 if (set_nr_and_not_polling(curr
))
593 smp_send_reschedule(cpu
);
595 trace_sched_wake_idle_without_ipi(cpu
);
598 void resched_cpu(int cpu
)
600 struct rq
*rq
= cpu_rq(cpu
);
603 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
606 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
610 #ifdef CONFIG_NO_HZ_COMMON
612 * In the semi idle case, use the nearest busy cpu for migrating timers
613 * from an idle cpu. This is good for power-savings.
615 * We don't do similar optimization for completely idle system, as
616 * selecting an idle cpu will add more delays to the timers than intended
617 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
619 int get_nohz_timer_target(void)
621 int i
, cpu
= smp_processor_id();
622 struct sched_domain
*sd
;
624 if (!idle_cpu(cpu
) && is_housekeeping_cpu(cpu
))
628 for_each_domain(cpu
, sd
) {
629 for_each_cpu(i
, sched_domain_span(sd
)) {
630 if (!idle_cpu(i
) && is_housekeeping_cpu(cpu
)) {
637 if (!is_housekeeping_cpu(cpu
))
638 cpu
= housekeeping_any_cpu();
644 * When add_timer_on() enqueues a timer into the timer wheel of an
645 * idle CPU then this timer might expire before the next timer event
646 * which is scheduled to wake up that CPU. In case of a completely
647 * idle system the next event might even be infinite time into the
648 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
649 * leaves the inner idle loop so the newly added timer is taken into
650 * account when the CPU goes back to idle and evaluates the timer
651 * wheel for the next timer event.
653 static void wake_up_idle_cpu(int cpu
)
655 struct rq
*rq
= cpu_rq(cpu
);
657 if (cpu
== smp_processor_id())
660 if (set_nr_and_not_polling(rq
->idle
))
661 smp_send_reschedule(cpu
);
663 trace_sched_wake_idle_without_ipi(cpu
);
666 static bool wake_up_full_nohz_cpu(int cpu
)
669 * We just need the target to call irq_exit() and re-evaluate
670 * the next tick. The nohz full kick at least implies that.
671 * If needed we can still optimize that later with an
674 if (tick_nohz_full_cpu(cpu
)) {
675 if (cpu
!= smp_processor_id() ||
676 tick_nohz_tick_stopped())
677 tick_nohz_full_kick_cpu(cpu
);
684 void wake_up_nohz_cpu(int cpu
)
686 if (!wake_up_full_nohz_cpu(cpu
))
687 wake_up_idle_cpu(cpu
);
690 static inline bool got_nohz_idle_kick(void)
692 int cpu
= smp_processor_id();
694 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
697 if (idle_cpu(cpu
) && !need_resched())
701 * We can't run Idle Load Balance on this CPU for this time so we
702 * cancel it and clear NOHZ_BALANCE_KICK
704 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
708 #else /* CONFIG_NO_HZ_COMMON */
710 static inline bool got_nohz_idle_kick(void)
715 #endif /* CONFIG_NO_HZ_COMMON */
717 #ifdef CONFIG_NO_HZ_FULL
718 bool sched_can_stop_tick(void)
721 * FIFO realtime policy runs the highest priority task. Other runnable
722 * tasks are of a lower priority. The scheduler tick does nothing.
724 if (current
->policy
== SCHED_FIFO
)
728 * Round-robin realtime tasks time slice with other tasks at the same
729 * realtime priority. Is this task the only one at this priority?
731 if (current
->policy
== SCHED_RR
) {
732 struct sched_rt_entity
*rt_se
= ¤t
->rt
;
734 return rt_se
->run_list
.prev
== rt_se
->run_list
.next
;
738 * More than one running task need preemption.
739 * nr_running update is assumed to be visible
740 * after IPI is sent from wakers.
742 if (this_rq()->nr_running
> 1)
747 #endif /* CONFIG_NO_HZ_FULL */
749 void sched_avg_update(struct rq
*rq
)
751 s64 period
= sched_avg_period();
753 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
755 * Inline assembly required to prevent the compiler
756 * optimising this loop into a divmod call.
757 * See __iter_div_u64_rem() for another example of this.
759 asm("" : "+rm" (rq
->age_stamp
));
760 rq
->age_stamp
+= period
;
765 #endif /* CONFIG_SMP */
767 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
768 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
770 * Iterate task_group tree rooted at *from, calling @down when first entering a
771 * node and @up when leaving it for the final time.
773 * Caller must hold rcu_lock or sufficient equivalent.
775 int walk_tg_tree_from(struct task_group
*from
,
776 tg_visitor down
, tg_visitor up
, void *data
)
778 struct task_group
*parent
, *child
;
784 ret
= (*down
)(parent
, data
);
787 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
794 ret
= (*up
)(parent
, data
);
795 if (ret
|| parent
== from
)
799 parent
= parent
->parent
;
806 int tg_nop(struct task_group
*tg
, void *data
)
812 static void set_load_weight(struct task_struct
*p
)
814 int prio
= p
->static_prio
- MAX_RT_PRIO
;
815 struct load_weight
*load
= &p
->se
.load
;
818 * SCHED_IDLE tasks get minimal weight:
820 if (p
->policy
== SCHED_IDLE
) {
821 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
822 load
->inv_weight
= WMULT_IDLEPRIO
;
826 load
->weight
= scale_load(prio_to_weight
[prio
]);
827 load
->inv_weight
= prio_to_wmult
[prio
];
830 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
833 sched_info_queued(rq
, p
);
834 p
->sched_class
->enqueue_task(rq
, p
, flags
);
837 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
840 sched_info_dequeued(rq
, p
);
841 p
->sched_class
->dequeue_task(rq
, p
, flags
);
844 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
846 if (task_contributes_to_load(p
))
847 rq
->nr_uninterruptible
--;
849 enqueue_task(rq
, p
, flags
);
852 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
854 if (task_contributes_to_load(p
))
855 rq
->nr_uninterruptible
++;
857 dequeue_task(rq
, p
, flags
);
860 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
863 * In theory, the compile should just see 0 here, and optimize out the call
864 * to sched_rt_avg_update. But I don't trust it...
866 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
867 s64 steal
= 0, irq_delta
= 0;
869 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
870 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
873 * Since irq_time is only updated on {soft,}irq_exit, we might run into
874 * this case when a previous update_rq_clock() happened inside a
877 * When this happens, we stop ->clock_task and only update the
878 * prev_irq_time stamp to account for the part that fit, so that a next
879 * update will consume the rest. This ensures ->clock_task is
882 * It does however cause some slight miss-attribution of {soft,}irq
883 * time, a more accurate solution would be to update the irq_time using
884 * the current rq->clock timestamp, except that would require using
887 if (irq_delta
> delta
)
890 rq
->prev_irq_time
+= irq_delta
;
893 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
894 if (static_key_false((¶virt_steal_rq_enabled
))) {
895 steal
= paravirt_steal_clock(cpu_of(rq
));
896 steal
-= rq
->prev_steal_time_rq
;
898 if (unlikely(steal
> delta
))
901 rq
->prev_steal_time_rq
+= steal
;
906 rq
->clock_task
+= delta
;
908 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
909 if ((irq_delta
+ steal
) && sched_feat(NONTASK_CAPACITY
))
910 sched_rt_avg_update(rq
, irq_delta
+ steal
);
914 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
916 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
917 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
921 * Make it appear like a SCHED_FIFO task, its something
922 * userspace knows about and won't get confused about.
924 * Also, it will make PI more or less work without too
925 * much confusion -- but then, stop work should not
926 * rely on PI working anyway.
928 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
930 stop
->sched_class
= &stop_sched_class
;
933 cpu_rq(cpu
)->stop
= stop
;
937 * Reset it back to a normal scheduling class so that
938 * it can die in pieces.
940 old_stop
->sched_class
= &rt_sched_class
;
945 * __normal_prio - return the priority that is based on the static prio
947 static inline int __normal_prio(struct task_struct
*p
)
949 return p
->static_prio
;
953 * Calculate the expected normal priority: i.e. priority
954 * without taking RT-inheritance into account. Might be
955 * boosted by interactivity modifiers. Changes upon fork,
956 * setprio syscalls, and whenever the interactivity
957 * estimator recalculates.
959 static inline int normal_prio(struct task_struct
*p
)
963 if (task_has_dl_policy(p
))
964 prio
= MAX_DL_PRIO
-1;
965 else if (task_has_rt_policy(p
))
966 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
968 prio
= __normal_prio(p
);
973 * Calculate the current priority, i.e. the priority
974 * taken into account by the scheduler. This value might
975 * be boosted by RT tasks, or might be boosted by
976 * interactivity modifiers. Will be RT if the task got
977 * RT-boosted. If not then it returns p->normal_prio.
979 static int effective_prio(struct task_struct
*p
)
981 p
->normal_prio
= normal_prio(p
);
983 * If we are RT tasks or we were boosted to RT priority,
984 * keep the priority unchanged. Otherwise, update priority
985 * to the normal priority:
987 if (!rt_prio(p
->prio
))
988 return p
->normal_prio
;
993 * task_curr - is this task currently executing on a CPU?
994 * @p: the task in question.
996 * Return: 1 if the task is currently executing. 0 otherwise.
998 inline int task_curr(const struct task_struct
*p
)
1000 return cpu_curr(task_cpu(p
)) == p
;
1004 * switched_from, switched_to and prio_changed must _NOT_ drop rq->lock,
1005 * use the balance_callback list if you want balancing.
1007 * this means any call to check_class_changed() must be followed by a call to
1008 * balance_callback().
1010 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1011 const struct sched_class
*prev_class
,
1014 if (prev_class
!= p
->sched_class
) {
1015 if (prev_class
->switched_from
)
1016 prev_class
->switched_from(rq
, p
);
1018 p
->sched_class
->switched_to(rq
, p
);
1019 } else if (oldprio
!= p
->prio
|| dl_task(p
))
1020 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
1023 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
1025 const struct sched_class
*class;
1027 if (p
->sched_class
== rq
->curr
->sched_class
) {
1028 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
1030 for_each_class(class) {
1031 if (class == rq
->curr
->sched_class
)
1033 if (class == p
->sched_class
) {
1041 * A queue event has occurred, and we're going to schedule. In
1042 * this case, we can save a useless back to back clock update.
1044 if (task_on_rq_queued(rq
->curr
) && test_tsk_need_resched(rq
->curr
))
1045 rq_clock_skip_update(rq
, true);
1050 * This is how migration works:
1052 * 1) we invoke migration_cpu_stop() on the target CPU using
1054 * 2) stopper starts to run (implicitly forcing the migrated thread
1056 * 3) it checks whether the migrated task is still in the wrong runqueue.
1057 * 4) if it's in the wrong runqueue then the migration thread removes
1058 * it and puts it into the right queue.
1059 * 5) stopper completes and stop_one_cpu() returns and the migration
1064 * move_queued_task - move a queued task to new rq.
1066 * Returns (locked) new rq. Old rq's lock is released.
1068 static struct rq
*move_queued_task(struct rq
*rq
, struct task_struct
*p
, int new_cpu
)
1070 lockdep_assert_held(&rq
->lock
);
1072 dequeue_task(rq
, p
, 0);
1073 p
->on_rq
= TASK_ON_RQ_MIGRATING
;
1074 set_task_cpu(p
, new_cpu
);
1075 raw_spin_unlock(&rq
->lock
);
1077 rq
= cpu_rq(new_cpu
);
1079 raw_spin_lock(&rq
->lock
);
1080 BUG_ON(task_cpu(p
) != new_cpu
);
1081 p
->on_rq
= TASK_ON_RQ_QUEUED
;
1082 enqueue_task(rq
, p
, 0);
1083 check_preempt_curr(rq
, p
, 0);
1088 struct migration_arg
{
1089 struct task_struct
*task
;
1094 * Move (not current) task off this cpu, onto dest cpu. We're doing
1095 * this because either it can't run here any more (set_cpus_allowed()
1096 * away from this CPU, or CPU going down), or because we're
1097 * attempting to rebalance this task on exec (sched_exec).
1099 * So we race with normal scheduler movements, but that's OK, as long
1100 * as the task is no longer on this CPU.
1102 static struct rq
*__migrate_task(struct rq
*rq
, struct task_struct
*p
, int dest_cpu
)
1104 if (unlikely(!cpu_active(dest_cpu
)))
1107 /* Affinity changed (again). */
1108 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1111 rq
= move_queued_task(rq
, p
, dest_cpu
);
1117 * migration_cpu_stop - this will be executed by a highprio stopper thread
1118 * and performs thread migration by bumping thread off CPU then
1119 * 'pushing' onto another runqueue.
1121 static int migration_cpu_stop(void *data
)
1123 struct migration_arg
*arg
= data
;
1124 struct task_struct
*p
= arg
->task
;
1125 struct rq
*rq
= this_rq();
1128 * The original target cpu might have gone down and we might
1129 * be on another cpu but it doesn't matter.
1131 local_irq_disable();
1133 * We need to explicitly wake pending tasks before running
1134 * __migrate_task() such that we will not miss enforcing cpus_allowed
1135 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
1137 sched_ttwu_pending();
1139 raw_spin_lock(&p
->pi_lock
);
1140 raw_spin_lock(&rq
->lock
);
1142 * If task_rq(p) != rq, it cannot be migrated here, because we're
1143 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
1144 * we're holding p->pi_lock.
1146 if (task_rq(p
) == rq
&& task_on_rq_queued(p
))
1147 rq
= __migrate_task(rq
, p
, arg
->dest_cpu
);
1148 raw_spin_unlock(&rq
->lock
);
1149 raw_spin_unlock(&p
->pi_lock
);
1156 * sched_class::set_cpus_allowed must do the below, but is not required to
1157 * actually call this function.
1159 void set_cpus_allowed_common(struct task_struct
*p
, const struct cpumask
*new_mask
)
1161 cpumask_copy(&p
->cpus_allowed
, new_mask
);
1162 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
1165 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
1167 struct rq
*rq
= task_rq(p
);
1168 bool queued
, running
;
1170 lockdep_assert_held(&p
->pi_lock
);
1172 queued
= task_on_rq_queued(p
);
1173 running
= task_current(rq
, p
);
1177 * Because __kthread_bind() calls this on blocked tasks without
1180 lockdep_assert_held(&rq
->lock
);
1181 dequeue_task(rq
, p
, 0);
1184 put_prev_task(rq
, p
);
1186 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
1189 p
->sched_class
->set_curr_task(rq
);
1191 enqueue_task(rq
, p
, 0);
1195 * Change a given task's CPU affinity. Migrate the thread to a
1196 * proper CPU and schedule it away if the CPU it's executing on
1197 * is removed from the allowed bitmask.
1199 * NOTE: the caller must have a valid reference to the task, the
1200 * task must not exit() & deallocate itself prematurely. The
1201 * call is not atomic; no spinlocks may be held.
1203 static int __set_cpus_allowed_ptr(struct task_struct
*p
,
1204 const struct cpumask
*new_mask
, bool check
)
1206 unsigned long flags
;
1208 unsigned int dest_cpu
;
1211 rq
= task_rq_lock(p
, &flags
);
1214 * Must re-check here, to close a race against __kthread_bind(),
1215 * sched_setaffinity() is not guaranteed to observe the flag.
1217 if (check
&& (p
->flags
& PF_NO_SETAFFINITY
)) {
1222 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
1225 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
1230 do_set_cpus_allowed(p
, new_mask
);
1232 /* Can the task run on the task's current CPU? If so, we're done */
1233 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
1236 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
1237 if (task_running(rq
, p
) || p
->state
== TASK_WAKING
) {
1238 struct migration_arg arg
= { p
, dest_cpu
};
1239 /* Need help from migration thread: drop lock and wait. */
1240 task_rq_unlock(rq
, p
, &flags
);
1241 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
1242 tlb_migrate_finish(p
->mm
);
1244 } else if (task_on_rq_queued(p
)) {
1246 * OK, since we're going to drop the lock immediately
1247 * afterwards anyway.
1249 lockdep_unpin_lock(&rq
->lock
);
1250 rq
= move_queued_task(rq
, p
, dest_cpu
);
1251 lockdep_pin_lock(&rq
->lock
);
1254 task_rq_unlock(rq
, p
, &flags
);
1259 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
1261 return __set_cpus_allowed_ptr(p
, new_mask
, false);
1263 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
1265 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1267 #ifdef CONFIG_SCHED_DEBUG
1269 * We should never call set_task_cpu() on a blocked task,
1270 * ttwu() will sort out the placement.
1272 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
1275 #ifdef CONFIG_LOCKDEP
1277 * The caller should hold either p->pi_lock or rq->lock, when changing
1278 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1280 * sched_move_task() holds both and thus holding either pins the cgroup,
1283 * Furthermore, all task_rq users should acquire both locks, see
1286 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1287 lockdep_is_held(&task_rq(p
)->lock
)));
1291 trace_sched_migrate_task(p
, new_cpu
);
1293 if (task_cpu(p
) != new_cpu
) {
1294 if (p
->sched_class
->migrate_task_rq
)
1295 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1296 p
->se
.nr_migrations
++;
1297 perf_event_task_migrate(p
);
1300 __set_task_cpu(p
, new_cpu
);
1303 static void __migrate_swap_task(struct task_struct
*p
, int cpu
)
1305 if (task_on_rq_queued(p
)) {
1306 struct rq
*src_rq
, *dst_rq
;
1308 src_rq
= task_rq(p
);
1309 dst_rq
= cpu_rq(cpu
);
1311 deactivate_task(src_rq
, p
, 0);
1312 set_task_cpu(p
, cpu
);
1313 activate_task(dst_rq
, p
, 0);
1314 check_preempt_curr(dst_rq
, p
, 0);
1317 * Task isn't running anymore; make it appear like we migrated
1318 * it before it went to sleep. This means on wakeup we make the
1319 * previous cpu our targer instead of where it really is.
1325 struct migration_swap_arg
{
1326 struct task_struct
*src_task
, *dst_task
;
1327 int src_cpu
, dst_cpu
;
1330 static int migrate_swap_stop(void *data
)
1332 struct migration_swap_arg
*arg
= data
;
1333 struct rq
*src_rq
, *dst_rq
;
1336 src_rq
= cpu_rq(arg
->src_cpu
);
1337 dst_rq
= cpu_rq(arg
->dst_cpu
);
1339 double_raw_lock(&arg
->src_task
->pi_lock
,
1340 &arg
->dst_task
->pi_lock
);
1341 double_rq_lock(src_rq
, dst_rq
);
1342 if (task_cpu(arg
->dst_task
) != arg
->dst_cpu
)
1345 if (task_cpu(arg
->src_task
) != arg
->src_cpu
)
1348 if (!cpumask_test_cpu(arg
->dst_cpu
, tsk_cpus_allowed(arg
->src_task
)))
1351 if (!cpumask_test_cpu(arg
->src_cpu
, tsk_cpus_allowed(arg
->dst_task
)))
1354 __migrate_swap_task(arg
->src_task
, arg
->dst_cpu
);
1355 __migrate_swap_task(arg
->dst_task
, arg
->src_cpu
);
1360 double_rq_unlock(src_rq
, dst_rq
);
1361 raw_spin_unlock(&arg
->dst_task
->pi_lock
);
1362 raw_spin_unlock(&arg
->src_task
->pi_lock
);
1368 * Cross migrate two tasks
1370 int migrate_swap(struct task_struct
*cur
, struct task_struct
*p
)
1372 struct migration_swap_arg arg
;
1375 arg
= (struct migration_swap_arg
){
1377 .src_cpu
= task_cpu(cur
),
1379 .dst_cpu
= task_cpu(p
),
1382 if (arg
.src_cpu
== arg
.dst_cpu
)
1386 * These three tests are all lockless; this is OK since all of them
1387 * will be re-checked with proper locks held further down the line.
1389 if (!cpu_active(arg
.src_cpu
) || !cpu_active(arg
.dst_cpu
))
1392 if (!cpumask_test_cpu(arg
.dst_cpu
, tsk_cpus_allowed(arg
.src_task
)))
1395 if (!cpumask_test_cpu(arg
.src_cpu
, tsk_cpus_allowed(arg
.dst_task
)))
1398 trace_sched_swap_numa(cur
, arg
.src_cpu
, p
, arg
.dst_cpu
);
1399 ret
= stop_two_cpus(arg
.dst_cpu
, arg
.src_cpu
, migrate_swap_stop
, &arg
);
1406 * wait_task_inactive - wait for a thread to unschedule.
1408 * If @match_state is nonzero, it's the @p->state value just checked and
1409 * not expected to change. If it changes, i.e. @p might have woken up,
1410 * then return zero. When we succeed in waiting for @p to be off its CPU,
1411 * we return a positive number (its total switch count). If a second call
1412 * a short while later returns the same number, the caller can be sure that
1413 * @p has remained unscheduled the whole time.
1415 * The caller must ensure that the task *will* unschedule sometime soon,
1416 * else this function might spin for a *long* time. This function can't
1417 * be called with interrupts off, or it may introduce deadlock with
1418 * smp_call_function() if an IPI is sent by the same process we are
1419 * waiting to become inactive.
1421 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1423 unsigned long flags
;
1424 int running
, queued
;
1430 * We do the initial early heuristics without holding
1431 * any task-queue locks at all. We'll only try to get
1432 * the runqueue lock when things look like they will
1438 * If the task is actively running on another CPU
1439 * still, just relax and busy-wait without holding
1442 * NOTE! Since we don't hold any locks, it's not
1443 * even sure that "rq" stays as the right runqueue!
1444 * But we don't care, since "task_running()" will
1445 * return false if the runqueue has changed and p
1446 * is actually now running somewhere else!
1448 while (task_running(rq
, p
)) {
1449 if (match_state
&& unlikely(p
->state
!= match_state
))
1455 * Ok, time to look more closely! We need the rq
1456 * lock now, to be *sure*. If we're wrong, we'll
1457 * just go back and repeat.
1459 rq
= task_rq_lock(p
, &flags
);
1460 trace_sched_wait_task(p
);
1461 running
= task_running(rq
, p
);
1462 queued
= task_on_rq_queued(p
);
1464 if (!match_state
|| p
->state
== match_state
)
1465 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1466 task_rq_unlock(rq
, p
, &flags
);
1469 * If it changed from the expected state, bail out now.
1471 if (unlikely(!ncsw
))
1475 * Was it really running after all now that we
1476 * checked with the proper locks actually held?
1478 * Oops. Go back and try again..
1480 if (unlikely(running
)) {
1486 * It's not enough that it's not actively running,
1487 * it must be off the runqueue _entirely_, and not
1490 * So if it was still runnable (but just not actively
1491 * running right now), it's preempted, and we should
1492 * yield - it could be a while.
1494 if (unlikely(queued
)) {
1495 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1497 set_current_state(TASK_UNINTERRUPTIBLE
);
1498 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1503 * Ahh, all good. It wasn't running, and it wasn't
1504 * runnable, which means that it will never become
1505 * running in the future either. We're all done!
1514 * kick_process - kick a running thread to enter/exit the kernel
1515 * @p: the to-be-kicked thread
1517 * Cause a process which is running on another CPU to enter
1518 * kernel-mode, without any delay. (to get signals handled.)
1520 * NOTE: this function doesn't have to take the runqueue lock,
1521 * because all it wants to ensure is that the remote task enters
1522 * the kernel. If the IPI races and the task has been migrated
1523 * to another CPU then no harm is done and the purpose has been
1526 void kick_process(struct task_struct
*p
)
1532 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1533 smp_send_reschedule(cpu
);
1536 EXPORT_SYMBOL_GPL(kick_process
);
1539 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1541 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1543 int nid
= cpu_to_node(cpu
);
1544 const struct cpumask
*nodemask
= NULL
;
1545 enum { cpuset
, possible
, fail
} state
= cpuset
;
1549 * If the node that the cpu is on has been offlined, cpu_to_node()
1550 * will return -1. There is no cpu on the node, and we should
1551 * select the cpu on the other node.
1554 nodemask
= cpumask_of_node(nid
);
1556 /* Look for allowed, online CPU in same node. */
1557 for_each_cpu(dest_cpu
, nodemask
) {
1558 if (!cpu_online(dest_cpu
))
1560 if (!cpu_active(dest_cpu
))
1562 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1568 /* Any allowed, online CPU? */
1569 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1570 if (!cpu_online(dest_cpu
))
1572 if (!cpu_active(dest_cpu
))
1579 /* No more Mr. Nice Guy. */
1580 cpuset_cpus_allowed_fallback(p
);
1585 do_set_cpus_allowed(p
, cpu_possible_mask
);
1596 if (state
!= cpuset
) {
1598 * Don't tell them about moving exiting tasks or
1599 * kernel threads (both mm NULL), since they never
1602 if (p
->mm
&& printk_ratelimit()) {
1603 printk_deferred("process %d (%s) no longer affine to cpu%d\n",
1604 task_pid_nr(p
), p
->comm
, cpu
);
1612 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1615 int select_task_rq(struct task_struct
*p
, int cpu
, int sd_flags
, int wake_flags
)
1617 lockdep_assert_held(&p
->pi_lock
);
1619 if (p
->nr_cpus_allowed
> 1)
1620 cpu
= p
->sched_class
->select_task_rq(p
, cpu
, sd_flags
, wake_flags
);
1623 * In order not to call set_task_cpu() on a blocking task we need
1624 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1627 * Since this is common to all placement strategies, this lives here.
1629 * [ this allows ->select_task() to simply return task_cpu(p) and
1630 * not worry about this generic constraint ]
1632 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1634 cpu
= select_fallback_rq(task_cpu(p
), p
);
1639 static void update_avg(u64
*avg
, u64 sample
)
1641 s64 diff
= sample
- *avg
;
1647 static inline int __set_cpus_allowed_ptr(struct task_struct
*p
,
1648 const struct cpumask
*new_mask
, bool check
)
1650 return set_cpus_allowed_ptr(p
, new_mask
);
1653 #endif /* CONFIG_SMP */
1656 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1658 #ifdef CONFIG_SCHEDSTATS
1659 struct rq
*rq
= this_rq();
1662 int this_cpu
= smp_processor_id();
1664 if (cpu
== this_cpu
) {
1665 schedstat_inc(rq
, ttwu_local
);
1666 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1668 struct sched_domain
*sd
;
1670 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1672 for_each_domain(this_cpu
, sd
) {
1673 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1674 schedstat_inc(sd
, ttwu_wake_remote
);
1681 if (wake_flags
& WF_MIGRATED
)
1682 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1684 #endif /* CONFIG_SMP */
1686 schedstat_inc(rq
, ttwu_count
);
1687 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1689 if (wake_flags
& WF_SYNC
)
1690 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1692 #endif /* CONFIG_SCHEDSTATS */
1695 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1697 activate_task(rq
, p
, en_flags
);
1698 p
->on_rq
= TASK_ON_RQ_QUEUED
;
1700 /* if a worker is waking up, notify workqueue */
1701 if (p
->flags
& PF_WQ_WORKER
)
1702 wq_worker_waking_up(p
, cpu_of(rq
));
1706 * Mark the task runnable and perform wakeup-preemption.
1709 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1711 check_preempt_curr(rq
, p
, wake_flags
);
1712 p
->state
= TASK_RUNNING
;
1713 trace_sched_wakeup(p
);
1716 if (p
->sched_class
->task_woken
) {
1718 * Our task @p is fully woken up and running; so its safe to
1719 * drop the rq->lock, hereafter rq is only used for statistics.
1721 lockdep_unpin_lock(&rq
->lock
);
1722 p
->sched_class
->task_woken(rq
, p
);
1723 lockdep_pin_lock(&rq
->lock
);
1726 if (rq
->idle_stamp
) {
1727 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1728 u64 max
= 2*rq
->max_idle_balance_cost
;
1730 update_avg(&rq
->avg_idle
, delta
);
1732 if (rq
->avg_idle
> max
)
1741 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1743 lockdep_assert_held(&rq
->lock
);
1746 if (p
->sched_contributes_to_load
)
1747 rq
->nr_uninterruptible
--;
1750 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1751 ttwu_do_wakeup(rq
, p
, wake_flags
);
1755 * Called in case the task @p isn't fully descheduled from its runqueue,
1756 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1757 * since all we need to do is flip p->state to TASK_RUNNING, since
1758 * the task is still ->on_rq.
1760 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1765 rq
= __task_rq_lock(p
);
1766 if (task_on_rq_queued(p
)) {
1767 /* check_preempt_curr() may use rq clock */
1768 update_rq_clock(rq
);
1769 ttwu_do_wakeup(rq
, p
, wake_flags
);
1772 __task_rq_unlock(rq
);
1778 void sched_ttwu_pending(void)
1780 struct rq
*rq
= this_rq();
1781 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1782 struct task_struct
*p
;
1783 unsigned long flags
;
1788 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1789 lockdep_pin_lock(&rq
->lock
);
1792 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1793 llist
= llist_next(llist
);
1794 ttwu_do_activate(rq
, p
, 0);
1797 lockdep_unpin_lock(&rq
->lock
);
1798 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1801 void scheduler_ipi(void)
1804 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1805 * TIF_NEED_RESCHED remotely (for the first time) will also send
1808 preempt_fold_need_resched();
1810 if (llist_empty(&this_rq()->wake_list
) && !got_nohz_idle_kick())
1814 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1815 * traditionally all their work was done from the interrupt return
1816 * path. Now that we actually do some work, we need to make sure
1819 * Some archs already do call them, luckily irq_enter/exit nest
1822 * Arguably we should visit all archs and update all handlers,
1823 * however a fair share of IPIs are still resched only so this would
1824 * somewhat pessimize the simple resched case.
1827 sched_ttwu_pending();
1830 * Check if someone kicked us for doing the nohz idle load balance.
1832 if (unlikely(got_nohz_idle_kick())) {
1833 this_rq()->idle_balance
= 1;
1834 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1839 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1841 struct rq
*rq
= cpu_rq(cpu
);
1843 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
)) {
1844 if (!set_nr_if_polling(rq
->idle
))
1845 smp_send_reschedule(cpu
);
1847 trace_sched_wake_idle_without_ipi(cpu
);
1851 void wake_up_if_idle(int cpu
)
1853 struct rq
*rq
= cpu_rq(cpu
);
1854 unsigned long flags
;
1858 if (!is_idle_task(rcu_dereference(rq
->curr
)))
1861 if (set_nr_if_polling(rq
->idle
)) {
1862 trace_sched_wake_idle_without_ipi(cpu
);
1864 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1865 if (is_idle_task(rq
->curr
))
1866 smp_send_reschedule(cpu
);
1867 /* Else cpu is not in idle, do nothing here */
1868 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1875 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1877 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1879 #endif /* CONFIG_SMP */
1881 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1883 struct rq
*rq
= cpu_rq(cpu
);
1885 #if defined(CONFIG_SMP)
1886 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1887 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1888 ttwu_queue_remote(p
, cpu
);
1893 raw_spin_lock(&rq
->lock
);
1894 lockdep_pin_lock(&rq
->lock
);
1895 ttwu_do_activate(rq
, p
, 0);
1896 lockdep_unpin_lock(&rq
->lock
);
1897 raw_spin_unlock(&rq
->lock
);
1901 * try_to_wake_up - wake up a thread
1902 * @p: the thread to be awakened
1903 * @state: the mask of task states that can be woken
1904 * @wake_flags: wake modifier flags (WF_*)
1906 * Put it on the run-queue if it's not already there. The "current"
1907 * thread is always on the run-queue (except when the actual
1908 * re-schedule is in progress), and as such you're allowed to do
1909 * the simpler "current->state = TASK_RUNNING" to mark yourself
1910 * runnable without the overhead of this.
1912 * Return: %true if @p was woken up, %false if it was already running.
1913 * or @state didn't match @p's state.
1916 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1918 unsigned long flags
;
1919 int cpu
, success
= 0;
1922 * If we are going to wake up a thread waiting for CONDITION we
1923 * need to ensure that CONDITION=1 done by the caller can not be
1924 * reordered with p->state check below. This pairs with mb() in
1925 * set_current_state() the waiting thread does.
1927 smp_mb__before_spinlock();
1928 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1929 if (!(p
->state
& state
))
1932 trace_sched_waking(p
);
1934 success
= 1; /* we're going to change ->state */
1937 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1942 * If the owning (remote) cpu is still in the middle of schedule() with
1943 * this task as prev, wait until its done referencing the task.
1948 * Pairs with the smp_wmb() in finish_lock_switch().
1952 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1953 p
->state
= TASK_WAKING
;
1955 if (p
->sched_class
->task_waking
)
1956 p
->sched_class
->task_waking(p
);
1958 cpu
= select_task_rq(p
, p
->wake_cpu
, SD_BALANCE_WAKE
, wake_flags
);
1959 if (task_cpu(p
) != cpu
) {
1960 wake_flags
|= WF_MIGRATED
;
1961 set_task_cpu(p
, cpu
);
1963 #endif /* CONFIG_SMP */
1967 ttwu_stat(p
, cpu
, wake_flags
);
1969 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1975 * try_to_wake_up_local - try to wake up a local task with rq lock held
1976 * @p: the thread to be awakened
1978 * Put @p on the run-queue if it's not already there. The caller must
1979 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1982 static void try_to_wake_up_local(struct task_struct
*p
)
1984 struct rq
*rq
= task_rq(p
);
1986 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1987 WARN_ON_ONCE(p
== current
))
1990 lockdep_assert_held(&rq
->lock
);
1992 if (!raw_spin_trylock(&p
->pi_lock
)) {
1994 * This is OK, because current is on_cpu, which avoids it being
1995 * picked for load-balance and preemption/IRQs are still
1996 * disabled avoiding further scheduler activity on it and we've
1997 * not yet picked a replacement task.
1999 lockdep_unpin_lock(&rq
->lock
);
2000 raw_spin_unlock(&rq
->lock
);
2001 raw_spin_lock(&p
->pi_lock
);
2002 raw_spin_lock(&rq
->lock
);
2003 lockdep_pin_lock(&rq
->lock
);
2006 if (!(p
->state
& TASK_NORMAL
))
2009 trace_sched_waking(p
);
2011 if (!task_on_rq_queued(p
))
2012 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
2014 ttwu_do_wakeup(rq
, p
, 0);
2015 ttwu_stat(p
, smp_processor_id(), 0);
2017 raw_spin_unlock(&p
->pi_lock
);
2021 * wake_up_process - Wake up a specific process
2022 * @p: The process to be woken up.
2024 * Attempt to wake up the nominated process and move it to the set of runnable
2027 * Return: 1 if the process was woken up, 0 if it was already running.
2029 * It may be assumed that this function implies a write memory barrier before
2030 * changing the task state if and only if any tasks are woken up.
2032 int wake_up_process(struct task_struct
*p
)
2034 WARN_ON(task_is_stopped_or_traced(p
));
2035 return try_to_wake_up(p
, TASK_NORMAL
, 0);
2037 EXPORT_SYMBOL(wake_up_process
);
2039 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2041 return try_to_wake_up(p
, state
, 0);
2045 * This function clears the sched_dl_entity static params.
2047 void __dl_clear_params(struct task_struct
*p
)
2049 struct sched_dl_entity
*dl_se
= &p
->dl
;
2051 dl_se
->dl_runtime
= 0;
2052 dl_se
->dl_deadline
= 0;
2053 dl_se
->dl_period
= 0;
2057 dl_se
->dl_throttled
= 0;
2059 dl_se
->dl_yielded
= 0;
2063 * Perform scheduler related setup for a newly forked process p.
2064 * p is forked by current.
2066 * __sched_fork() is basic setup used by init_idle() too:
2068 static void __sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
2073 p
->se
.exec_start
= 0;
2074 p
->se
.sum_exec_runtime
= 0;
2075 p
->se
.prev_sum_exec_runtime
= 0;
2076 p
->se
.nr_migrations
= 0;
2078 INIT_LIST_HEAD(&p
->se
.group_node
);
2080 #ifdef CONFIG_SCHEDSTATS
2081 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
2084 RB_CLEAR_NODE(&p
->dl
.rb_node
);
2085 init_dl_task_timer(&p
->dl
);
2086 __dl_clear_params(p
);
2088 INIT_LIST_HEAD(&p
->rt
.run_list
);
2090 #ifdef CONFIG_PREEMPT_NOTIFIERS
2091 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2094 #ifdef CONFIG_NUMA_BALANCING
2095 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
2096 p
->mm
->numa_next_scan
= jiffies
+ msecs_to_jiffies(sysctl_numa_balancing_scan_delay
);
2097 p
->mm
->numa_scan_seq
= 0;
2100 if (clone_flags
& CLONE_VM
)
2101 p
->numa_preferred_nid
= current
->numa_preferred_nid
;
2103 p
->numa_preferred_nid
= -1;
2105 p
->node_stamp
= 0ULL;
2106 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
2107 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
2108 p
->numa_work
.next
= &p
->numa_work
;
2109 p
->numa_faults
= NULL
;
2110 p
->last_task_numa_placement
= 0;
2111 p
->last_sum_exec_runtime
= 0;
2113 p
->numa_group
= NULL
;
2114 #endif /* CONFIG_NUMA_BALANCING */
2117 #ifdef CONFIG_NUMA_BALANCING
2118 #ifdef CONFIG_SCHED_DEBUG
2119 void set_numabalancing_state(bool enabled
)
2122 sched_feat_set("NUMA");
2124 sched_feat_set("NO_NUMA");
2127 __read_mostly
bool numabalancing_enabled
;
2129 void set_numabalancing_state(bool enabled
)
2131 numabalancing_enabled
= enabled
;
2133 #endif /* CONFIG_SCHED_DEBUG */
2135 #ifdef CONFIG_PROC_SYSCTL
2136 int sysctl_numa_balancing(struct ctl_table
*table
, int write
,
2137 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
2141 int state
= numabalancing_enabled
;
2143 if (write
&& !capable(CAP_SYS_ADMIN
))
2148 err
= proc_dointvec_minmax(&t
, write
, buffer
, lenp
, ppos
);
2152 set_numabalancing_state(state
);
2159 * fork()/clone()-time setup:
2161 int sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
2163 unsigned long flags
;
2164 int cpu
= get_cpu();
2166 __sched_fork(clone_flags
, p
);
2168 * We mark the process as running here. This guarantees that
2169 * nobody will actually run it, and a signal or other external
2170 * event cannot wake it up and insert it on the runqueue either.
2172 p
->state
= TASK_RUNNING
;
2175 * Make sure we do not leak PI boosting priority to the child.
2177 p
->prio
= current
->normal_prio
;
2180 * Revert to default priority/policy on fork if requested.
2182 if (unlikely(p
->sched_reset_on_fork
)) {
2183 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
2184 p
->policy
= SCHED_NORMAL
;
2185 p
->static_prio
= NICE_TO_PRIO(0);
2187 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
2188 p
->static_prio
= NICE_TO_PRIO(0);
2190 p
->prio
= p
->normal_prio
= __normal_prio(p
);
2194 * We don't need the reset flag anymore after the fork. It has
2195 * fulfilled its duty:
2197 p
->sched_reset_on_fork
= 0;
2200 if (dl_prio(p
->prio
)) {
2203 } else if (rt_prio(p
->prio
)) {
2204 p
->sched_class
= &rt_sched_class
;
2206 p
->sched_class
= &fair_sched_class
;
2209 if (p
->sched_class
->task_fork
)
2210 p
->sched_class
->task_fork(p
);
2213 * The child is not yet in the pid-hash so no cgroup attach races,
2214 * and the cgroup is pinned to this child due to cgroup_fork()
2215 * is ran before sched_fork().
2217 * Silence PROVE_RCU.
2219 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2220 set_task_cpu(p
, cpu
);
2221 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2223 #ifdef CONFIG_SCHED_INFO
2224 if (likely(sched_info_on()))
2225 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2227 #if defined(CONFIG_SMP)
2230 init_task_preempt_count(p
);
2232 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2233 RB_CLEAR_NODE(&p
->pushable_dl_tasks
);
2240 unsigned long to_ratio(u64 period
, u64 runtime
)
2242 if (runtime
== RUNTIME_INF
)
2246 * Doing this here saves a lot of checks in all
2247 * the calling paths, and returning zero seems
2248 * safe for them anyway.
2253 return div64_u64(runtime
<< 20, period
);
2257 inline struct dl_bw
*dl_bw_of(int i
)
2259 RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
2260 "sched RCU must be held");
2261 return &cpu_rq(i
)->rd
->dl_bw
;
2264 static inline int dl_bw_cpus(int i
)
2266 struct root_domain
*rd
= cpu_rq(i
)->rd
;
2269 RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
2270 "sched RCU must be held");
2271 for_each_cpu_and(i
, rd
->span
, cpu_active_mask
)
2277 inline struct dl_bw
*dl_bw_of(int i
)
2279 return &cpu_rq(i
)->dl
.dl_bw
;
2282 static inline int dl_bw_cpus(int i
)
2289 * We must be sure that accepting a new task (or allowing changing the
2290 * parameters of an existing one) is consistent with the bandwidth
2291 * constraints. If yes, this function also accordingly updates the currently
2292 * allocated bandwidth to reflect the new situation.
2294 * This function is called while holding p's rq->lock.
2296 * XXX we should delay bw change until the task's 0-lag point, see
2299 static int dl_overflow(struct task_struct
*p
, int policy
,
2300 const struct sched_attr
*attr
)
2303 struct dl_bw
*dl_b
= dl_bw_of(task_cpu(p
));
2304 u64 period
= attr
->sched_period
?: attr
->sched_deadline
;
2305 u64 runtime
= attr
->sched_runtime
;
2306 u64 new_bw
= dl_policy(policy
) ? to_ratio(period
, runtime
) : 0;
2309 if (new_bw
== p
->dl
.dl_bw
)
2313 * Either if a task, enters, leave, or stays -deadline but changes
2314 * its parameters, we may need to update accordingly the total
2315 * allocated bandwidth of the container.
2317 raw_spin_lock(&dl_b
->lock
);
2318 cpus
= dl_bw_cpus(task_cpu(p
));
2319 if (dl_policy(policy
) && !task_has_dl_policy(p
) &&
2320 !__dl_overflow(dl_b
, cpus
, 0, new_bw
)) {
2321 __dl_add(dl_b
, new_bw
);
2323 } else if (dl_policy(policy
) && task_has_dl_policy(p
) &&
2324 !__dl_overflow(dl_b
, cpus
, p
->dl
.dl_bw
, new_bw
)) {
2325 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2326 __dl_add(dl_b
, new_bw
);
2328 } else if (!dl_policy(policy
) && task_has_dl_policy(p
)) {
2329 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2332 raw_spin_unlock(&dl_b
->lock
);
2337 extern void init_dl_bw(struct dl_bw
*dl_b
);
2340 * wake_up_new_task - wake up a newly created task for the first time.
2342 * This function will do some initial scheduler statistics housekeeping
2343 * that must be done for every newly created context, then puts the task
2344 * on the runqueue and wakes it.
2346 void wake_up_new_task(struct task_struct
*p
)
2348 unsigned long flags
;
2351 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2354 * Fork balancing, do it here and not earlier because:
2355 * - cpus_allowed can change in the fork path
2356 * - any previously selected cpu might disappear through hotplug
2358 set_task_cpu(p
, select_task_rq(p
, task_cpu(p
), SD_BALANCE_FORK
, 0));
2361 /* Initialize new task's runnable average */
2362 init_entity_runnable_average(&p
->se
);
2363 rq
= __task_rq_lock(p
);
2364 activate_task(rq
, p
, 0);
2365 p
->on_rq
= TASK_ON_RQ_QUEUED
;
2366 trace_sched_wakeup_new(p
);
2367 check_preempt_curr(rq
, p
, WF_FORK
);
2369 if (p
->sched_class
->task_woken
)
2370 p
->sched_class
->task_woken(rq
, p
);
2372 task_rq_unlock(rq
, p
, &flags
);
2375 #ifdef CONFIG_PREEMPT_NOTIFIERS
2377 static struct static_key preempt_notifier_key
= STATIC_KEY_INIT_FALSE
;
2379 void preempt_notifier_inc(void)
2381 static_key_slow_inc(&preempt_notifier_key
);
2383 EXPORT_SYMBOL_GPL(preempt_notifier_inc
);
2385 void preempt_notifier_dec(void)
2387 static_key_slow_dec(&preempt_notifier_key
);
2389 EXPORT_SYMBOL_GPL(preempt_notifier_dec
);
2392 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2393 * @notifier: notifier struct to register
2395 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2397 if (!static_key_false(&preempt_notifier_key
))
2398 WARN(1, "registering preempt_notifier while notifiers disabled\n");
2400 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2402 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2405 * preempt_notifier_unregister - no longer interested in preemption notifications
2406 * @notifier: notifier struct to unregister
2408 * This is *not* safe to call from within a preemption notifier.
2410 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2412 hlist_del(¬ifier
->link
);
2414 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2416 static void __fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2418 struct preempt_notifier
*notifier
;
2420 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2421 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2424 static __always_inline
void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2426 if (static_key_false(&preempt_notifier_key
))
2427 __fire_sched_in_preempt_notifiers(curr
);
2431 __fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2432 struct task_struct
*next
)
2434 struct preempt_notifier
*notifier
;
2436 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2437 notifier
->ops
->sched_out(notifier
, next
);
2440 static __always_inline
void
2441 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2442 struct task_struct
*next
)
2444 if (static_key_false(&preempt_notifier_key
))
2445 __fire_sched_out_preempt_notifiers(curr
, next
);
2448 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2450 static inline void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2455 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2456 struct task_struct
*next
)
2460 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2463 * prepare_task_switch - prepare to switch tasks
2464 * @rq: the runqueue preparing to switch
2465 * @prev: the current task that is being switched out
2466 * @next: the task we are going to switch to.
2468 * This is called with the rq lock held and interrupts off. It must
2469 * be paired with a subsequent finish_task_switch after the context
2472 * prepare_task_switch sets up locking and calls architecture specific
2476 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2477 struct task_struct
*next
)
2479 trace_sched_switch(prev
, next
);
2480 sched_info_switch(rq
, prev
, next
);
2481 perf_event_task_sched_out(prev
, next
);
2482 fire_sched_out_preempt_notifiers(prev
, next
);
2483 prepare_lock_switch(rq
, next
);
2484 prepare_arch_switch(next
);
2488 * finish_task_switch - clean up after a task-switch
2489 * @prev: the thread we just switched away from.
2491 * finish_task_switch must be called after the context switch, paired
2492 * with a prepare_task_switch call before the context switch.
2493 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2494 * and do any other architecture-specific cleanup actions.
2496 * Note that we may have delayed dropping an mm in context_switch(). If
2497 * so, we finish that here outside of the runqueue lock. (Doing it
2498 * with the lock held can cause deadlocks; see schedule() for
2501 * The context switch have flipped the stack from under us and restored the
2502 * local variables which were saved when this task called schedule() in the
2503 * past. prev == current is still correct but we need to recalculate this_rq
2504 * because prev may have moved to another CPU.
2506 static struct rq
*finish_task_switch(struct task_struct
*prev
)
2507 __releases(rq
->lock
)
2509 struct rq
*rq
= this_rq();
2510 struct mm_struct
*mm
= rq
->prev_mm
;
2516 * A task struct has one reference for the use as "current".
2517 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2518 * schedule one last time. The schedule call will never return, and
2519 * the scheduled task must drop that reference.
2520 * The test for TASK_DEAD must occur while the runqueue locks are
2521 * still held, otherwise prev could be scheduled on another cpu, die
2522 * there before we look at prev->state, and then the reference would
2524 * Manfred Spraul <manfred@colorfullife.com>
2526 prev_state
= prev
->state
;
2527 vtime_task_switch(prev
);
2528 perf_event_task_sched_in(prev
, current
);
2529 finish_lock_switch(rq
, prev
);
2530 finish_arch_post_lock_switch();
2532 fire_sched_in_preempt_notifiers(current
);
2535 if (unlikely(prev_state
== TASK_DEAD
)) {
2536 if (prev
->sched_class
->task_dead
)
2537 prev
->sched_class
->task_dead(prev
);
2540 * Remove function-return probe instances associated with this
2541 * task and put them back on the free list.
2543 kprobe_flush_task(prev
);
2544 put_task_struct(prev
);
2547 tick_nohz_task_switch();
2553 /* rq->lock is NOT held, but preemption is disabled */
2554 static void __balance_callback(struct rq
*rq
)
2556 struct callback_head
*head
, *next
;
2557 void (*func
)(struct rq
*rq
);
2558 unsigned long flags
;
2560 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2561 head
= rq
->balance_callback
;
2562 rq
->balance_callback
= NULL
;
2564 func
= (void (*)(struct rq
*))head
->func
;
2571 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2574 static inline void balance_callback(struct rq
*rq
)
2576 if (unlikely(rq
->balance_callback
))
2577 __balance_callback(rq
);
2582 static inline void balance_callback(struct rq
*rq
)
2589 * schedule_tail - first thing a freshly forked thread must call.
2590 * @prev: the thread we just switched away from.
2592 asmlinkage __visible
void schedule_tail(struct task_struct
*prev
)
2593 __releases(rq
->lock
)
2597 /* finish_task_switch() drops rq->lock and enables preemtion */
2599 rq
= finish_task_switch(prev
);
2600 balance_callback(rq
);
2603 if (current
->set_child_tid
)
2604 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2608 * context_switch - switch to the new MM and the new thread's register state.
2610 static inline struct rq
*
2611 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2612 struct task_struct
*next
)
2614 struct mm_struct
*mm
, *oldmm
;
2616 prepare_task_switch(rq
, prev
, next
);
2619 oldmm
= prev
->active_mm
;
2621 * For paravirt, this is coupled with an exit in switch_to to
2622 * combine the page table reload and the switch backend into
2625 arch_start_context_switch(prev
);
2628 next
->active_mm
= oldmm
;
2629 atomic_inc(&oldmm
->mm_count
);
2630 enter_lazy_tlb(oldmm
, next
);
2632 switch_mm(oldmm
, mm
, next
);
2635 prev
->active_mm
= NULL
;
2636 rq
->prev_mm
= oldmm
;
2639 * Since the runqueue lock will be released by the next
2640 * task (which is an invalid locking op but in the case
2641 * of the scheduler it's an obvious special-case), so we
2642 * do an early lockdep release here:
2644 lockdep_unpin_lock(&rq
->lock
);
2645 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2647 /* Here we just switch the register state and the stack. */
2648 switch_to(prev
, next
, prev
);
2651 return finish_task_switch(prev
);
2655 * nr_running and nr_context_switches:
2657 * externally visible scheduler statistics: current number of runnable
2658 * threads, total number of context switches performed since bootup.
2660 unsigned long nr_running(void)
2662 unsigned long i
, sum
= 0;
2664 for_each_online_cpu(i
)
2665 sum
+= cpu_rq(i
)->nr_running
;
2671 * Check if only the current task is running on the cpu.
2673 bool single_task_running(void)
2675 if (cpu_rq(smp_processor_id())->nr_running
== 1)
2680 EXPORT_SYMBOL(single_task_running
);
2682 unsigned long long nr_context_switches(void)
2685 unsigned long long sum
= 0;
2687 for_each_possible_cpu(i
)
2688 sum
+= cpu_rq(i
)->nr_switches
;
2693 unsigned long nr_iowait(void)
2695 unsigned long i
, sum
= 0;
2697 for_each_possible_cpu(i
)
2698 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2703 unsigned long nr_iowait_cpu(int cpu
)
2705 struct rq
*this = cpu_rq(cpu
);
2706 return atomic_read(&this->nr_iowait
);
2709 void get_iowait_load(unsigned long *nr_waiters
, unsigned long *load
)
2711 struct rq
*rq
= this_rq();
2712 *nr_waiters
= atomic_read(&rq
->nr_iowait
);
2713 *load
= rq
->load
.weight
;
2719 * sched_exec - execve() is a valuable balancing opportunity, because at
2720 * this point the task has the smallest effective memory and cache footprint.
2722 void sched_exec(void)
2724 struct task_struct
*p
= current
;
2725 unsigned long flags
;
2728 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2729 dest_cpu
= p
->sched_class
->select_task_rq(p
, task_cpu(p
), SD_BALANCE_EXEC
, 0);
2730 if (dest_cpu
== smp_processor_id())
2733 if (likely(cpu_active(dest_cpu
))) {
2734 struct migration_arg arg
= { p
, dest_cpu
};
2736 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2737 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2741 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2746 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2747 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2749 EXPORT_PER_CPU_SYMBOL(kstat
);
2750 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2753 * Return accounted runtime for the task.
2754 * In case the task is currently running, return the runtime plus current's
2755 * pending runtime that have not been accounted yet.
2757 unsigned long long task_sched_runtime(struct task_struct
*p
)
2759 unsigned long flags
;
2763 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2765 * 64-bit doesn't need locks to atomically read a 64bit value.
2766 * So we have a optimization chance when the task's delta_exec is 0.
2767 * Reading ->on_cpu is racy, but this is ok.
2769 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2770 * If we race with it entering cpu, unaccounted time is 0. This is
2771 * indistinguishable from the read occurring a few cycles earlier.
2772 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
2773 * been accounted, so we're correct here as well.
2775 if (!p
->on_cpu
|| !task_on_rq_queued(p
))
2776 return p
->se
.sum_exec_runtime
;
2779 rq
= task_rq_lock(p
, &flags
);
2781 * Must be ->curr _and_ ->on_rq. If dequeued, we would
2782 * project cycles that may never be accounted to this
2783 * thread, breaking clock_gettime().
2785 if (task_current(rq
, p
) && task_on_rq_queued(p
)) {
2786 update_rq_clock(rq
);
2787 p
->sched_class
->update_curr(rq
);
2789 ns
= p
->se
.sum_exec_runtime
;
2790 task_rq_unlock(rq
, p
, &flags
);
2796 * This function gets called by the timer code, with HZ frequency.
2797 * We call it with interrupts disabled.
2799 void scheduler_tick(void)
2801 int cpu
= smp_processor_id();
2802 struct rq
*rq
= cpu_rq(cpu
);
2803 struct task_struct
*curr
= rq
->curr
;
2807 raw_spin_lock(&rq
->lock
);
2808 update_rq_clock(rq
);
2809 curr
->sched_class
->task_tick(rq
, curr
, 0);
2810 update_cpu_load_active(rq
);
2811 calc_global_load_tick(rq
);
2812 raw_spin_unlock(&rq
->lock
);
2814 perf_event_task_tick();
2817 rq
->idle_balance
= idle_cpu(cpu
);
2818 trigger_load_balance(rq
);
2820 rq_last_tick_reset(rq
);
2823 #ifdef CONFIG_NO_HZ_FULL
2825 * scheduler_tick_max_deferment
2827 * Keep at least one tick per second when a single
2828 * active task is running because the scheduler doesn't
2829 * yet completely support full dynticks environment.
2831 * This makes sure that uptime, CFS vruntime, load
2832 * balancing, etc... continue to move forward, even
2833 * with a very low granularity.
2835 * Return: Maximum deferment in nanoseconds.
2837 u64
scheduler_tick_max_deferment(void)
2839 struct rq
*rq
= this_rq();
2840 unsigned long next
, now
= READ_ONCE(jiffies
);
2842 next
= rq
->last_sched_tick
+ HZ
;
2844 if (time_before_eq(next
, now
))
2847 return jiffies_to_nsecs(next
- now
);
2851 notrace
unsigned long get_parent_ip(unsigned long addr
)
2853 if (in_lock_functions(addr
)) {
2854 addr
= CALLER_ADDR2
;
2855 if (in_lock_functions(addr
))
2856 addr
= CALLER_ADDR3
;
2861 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2862 defined(CONFIG_PREEMPT_TRACER))
2864 void preempt_count_add(int val
)
2866 #ifdef CONFIG_DEBUG_PREEMPT
2870 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2873 __preempt_count_add(val
);
2874 #ifdef CONFIG_DEBUG_PREEMPT
2876 * Spinlock count overflowing soon?
2878 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2881 if (preempt_count() == val
) {
2882 unsigned long ip
= get_parent_ip(CALLER_ADDR1
);
2883 #ifdef CONFIG_DEBUG_PREEMPT
2884 current
->preempt_disable_ip
= ip
;
2886 trace_preempt_off(CALLER_ADDR0
, ip
);
2889 EXPORT_SYMBOL(preempt_count_add
);
2890 NOKPROBE_SYMBOL(preempt_count_add
);
2892 void preempt_count_sub(int val
)
2894 #ifdef CONFIG_DEBUG_PREEMPT
2898 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2901 * Is the spinlock portion underflowing?
2903 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2904 !(preempt_count() & PREEMPT_MASK
)))
2908 if (preempt_count() == val
)
2909 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2910 __preempt_count_sub(val
);
2912 EXPORT_SYMBOL(preempt_count_sub
);
2913 NOKPROBE_SYMBOL(preempt_count_sub
);
2918 * Print scheduling while atomic bug:
2920 static noinline
void __schedule_bug(struct task_struct
*prev
)
2922 if (oops_in_progress
)
2925 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2926 prev
->comm
, prev
->pid
, preempt_count());
2928 debug_show_held_locks(prev
);
2930 if (irqs_disabled())
2931 print_irqtrace_events(prev
);
2932 #ifdef CONFIG_DEBUG_PREEMPT
2933 if (in_atomic_preempt_off()) {
2934 pr_err("Preemption disabled at:");
2935 print_ip_sym(current
->preempt_disable_ip
);
2940 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2944 * Various schedule()-time debugging checks and statistics:
2946 static inline void schedule_debug(struct task_struct
*prev
)
2948 #ifdef CONFIG_SCHED_STACK_END_CHECK
2949 BUG_ON(unlikely(task_stack_end_corrupted(prev
)));
2952 * Test if we are atomic. Since do_exit() needs to call into
2953 * schedule() atomically, we ignore that path. Otherwise whine
2954 * if we are scheduling when we should not.
2956 if (unlikely(in_atomic_preempt_off() && prev
->state
!= TASK_DEAD
))
2957 __schedule_bug(prev
);
2960 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2962 schedstat_inc(this_rq(), sched_count
);
2966 * Pick up the highest-prio task:
2968 static inline struct task_struct
*
2969 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
2971 const struct sched_class
*class = &fair_sched_class
;
2972 struct task_struct
*p
;
2975 * Optimization: we know that if all tasks are in
2976 * the fair class we can call that function directly:
2978 if (likely(prev
->sched_class
== class &&
2979 rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2980 p
= fair_sched_class
.pick_next_task(rq
, prev
);
2981 if (unlikely(p
== RETRY_TASK
))
2984 /* assumes fair_sched_class->next == idle_sched_class */
2986 p
= idle_sched_class
.pick_next_task(rq
, prev
);
2992 for_each_class(class) {
2993 p
= class->pick_next_task(rq
, prev
);
2995 if (unlikely(p
== RETRY_TASK
))
3001 BUG(); /* the idle class will always have a runnable task */
3005 * __schedule() is the main scheduler function.
3007 * The main means of driving the scheduler and thus entering this function are:
3009 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
3011 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
3012 * paths. For example, see arch/x86/entry_64.S.
3014 * To drive preemption between tasks, the scheduler sets the flag in timer
3015 * interrupt handler scheduler_tick().
3017 * 3. Wakeups don't really cause entry into schedule(). They add a
3018 * task to the run-queue and that's it.
3020 * Now, if the new task added to the run-queue preempts the current
3021 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
3022 * called on the nearest possible occasion:
3024 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
3026 * - in syscall or exception context, at the next outmost
3027 * preempt_enable(). (this might be as soon as the wake_up()'s
3030 * - in IRQ context, return from interrupt-handler to
3031 * preemptible context
3033 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
3036 * - cond_resched() call
3037 * - explicit schedule() call
3038 * - return from syscall or exception to user-space
3039 * - return from interrupt-handler to user-space
3041 * WARNING: must be called with preemption disabled!
3043 static void __sched
__schedule(void)
3045 struct task_struct
*prev
, *next
;
3046 unsigned long *switch_count
;
3050 cpu
= smp_processor_id();
3052 rcu_note_context_switch();
3055 schedule_debug(prev
);
3057 if (sched_feat(HRTICK
))
3061 * Make sure that signal_pending_state()->signal_pending() below
3062 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
3063 * done by the caller to avoid the race with signal_wake_up().
3065 smp_mb__before_spinlock();
3066 raw_spin_lock_irq(&rq
->lock
);
3067 lockdep_pin_lock(&rq
->lock
);
3069 rq
->clock_skip_update
<<= 1; /* promote REQ to ACT */
3071 switch_count
= &prev
->nivcsw
;
3072 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
3073 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
3074 prev
->state
= TASK_RUNNING
;
3076 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
3080 * If a worker went to sleep, notify and ask workqueue
3081 * whether it wants to wake up a task to maintain
3084 if (prev
->flags
& PF_WQ_WORKER
) {
3085 struct task_struct
*to_wakeup
;
3087 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
3089 try_to_wake_up_local(to_wakeup
);
3092 switch_count
= &prev
->nvcsw
;
3095 if (task_on_rq_queued(prev
))
3096 update_rq_clock(rq
);
3098 next
= pick_next_task(rq
, prev
);
3099 clear_tsk_need_resched(prev
);
3100 clear_preempt_need_resched();
3101 rq
->clock_skip_update
= 0;
3103 if (likely(prev
!= next
)) {
3108 rq
= context_switch(rq
, prev
, next
); /* unlocks the rq */
3111 lockdep_unpin_lock(&rq
->lock
);
3112 raw_spin_unlock_irq(&rq
->lock
);
3115 balance_callback(rq
);
3118 static inline void sched_submit_work(struct task_struct
*tsk
)
3120 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
3123 * If we are going to sleep and we have plugged IO queued,
3124 * make sure to submit it to avoid deadlocks.
3126 if (blk_needs_flush_plug(tsk
))
3127 blk_schedule_flush_plug(tsk
);
3130 asmlinkage __visible
void __sched
schedule(void)
3132 struct task_struct
*tsk
= current
;
3134 sched_submit_work(tsk
);
3138 sched_preempt_enable_no_resched();
3139 } while (need_resched());
3141 EXPORT_SYMBOL(schedule
);
3143 #ifdef CONFIG_CONTEXT_TRACKING
3144 asmlinkage __visible
void __sched
schedule_user(void)
3147 * If we come here after a random call to set_need_resched(),
3148 * or we have been woken up remotely but the IPI has not yet arrived,
3149 * we haven't yet exited the RCU idle mode. Do it here manually until
3150 * we find a better solution.
3152 * NB: There are buggy callers of this function. Ideally we
3153 * should warn if prev_state != CONTEXT_USER, but that will trigger
3154 * too frequently to make sense yet.
3156 enum ctx_state prev_state
= exception_enter();
3158 exception_exit(prev_state
);
3163 * schedule_preempt_disabled - called with preemption disabled
3165 * Returns with preemption disabled. Note: preempt_count must be 1
3167 void __sched
schedule_preempt_disabled(void)
3169 sched_preempt_enable_no_resched();
3174 static void __sched notrace
preempt_schedule_common(void)
3177 preempt_active_enter();
3179 preempt_active_exit();
3182 * Check again in case we missed a preemption opportunity
3183 * between schedule and now.
3185 } while (need_resched());
3188 #ifdef CONFIG_PREEMPT
3190 * this is the entry point to schedule() from in-kernel preemption
3191 * off of preempt_enable. Kernel preemptions off return from interrupt
3192 * occur there and call schedule directly.
3194 asmlinkage __visible
void __sched notrace
preempt_schedule(void)
3197 * If there is a non-zero preempt_count or interrupts are disabled,
3198 * we do not want to preempt the current task. Just return..
3200 if (likely(!preemptible()))
3203 preempt_schedule_common();
3205 NOKPROBE_SYMBOL(preempt_schedule
);
3206 EXPORT_SYMBOL(preempt_schedule
);
3209 * preempt_schedule_notrace - preempt_schedule called by tracing
3211 * The tracing infrastructure uses preempt_enable_notrace to prevent
3212 * recursion and tracing preempt enabling caused by the tracing
3213 * infrastructure itself. But as tracing can happen in areas coming
3214 * from userspace or just about to enter userspace, a preempt enable
3215 * can occur before user_exit() is called. This will cause the scheduler
3216 * to be called when the system is still in usermode.
3218 * To prevent this, the preempt_enable_notrace will use this function
3219 * instead of preempt_schedule() to exit user context if needed before
3220 * calling the scheduler.
3222 asmlinkage __visible
void __sched notrace
preempt_schedule_notrace(void)
3224 enum ctx_state prev_ctx
;
3226 if (likely(!preemptible()))
3231 * Use raw __prempt_count() ops that don't call function.
3232 * We can't call functions before disabling preemption which
3233 * disarm preemption tracing recursions.
3235 __preempt_count_add(PREEMPT_ACTIVE
+ PREEMPT_DISABLE_OFFSET
);
3238 * Needs preempt disabled in case user_exit() is traced
3239 * and the tracer calls preempt_enable_notrace() causing
3240 * an infinite recursion.
3242 prev_ctx
= exception_enter();
3244 exception_exit(prev_ctx
);
3247 __preempt_count_sub(PREEMPT_ACTIVE
+ PREEMPT_DISABLE_OFFSET
);
3248 } while (need_resched());
3250 EXPORT_SYMBOL_GPL(preempt_schedule_notrace
);
3252 #endif /* CONFIG_PREEMPT */
3255 * this is the entry point to schedule() from kernel preemption
3256 * off of irq context.
3257 * Note, that this is called and return with irqs disabled. This will
3258 * protect us against recursive calling from irq.
3260 asmlinkage __visible
void __sched
preempt_schedule_irq(void)
3262 enum ctx_state prev_state
;
3264 /* Catch callers which need to be fixed */
3265 BUG_ON(preempt_count() || !irqs_disabled());
3267 prev_state
= exception_enter();
3270 preempt_active_enter();
3273 local_irq_disable();
3274 preempt_active_exit();
3275 } while (need_resched());
3277 exception_exit(prev_state
);
3280 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
3283 return try_to_wake_up(curr
->private, mode
, wake_flags
);
3285 EXPORT_SYMBOL(default_wake_function
);
3287 #ifdef CONFIG_RT_MUTEXES
3290 * rt_mutex_setprio - set the current priority of a task
3292 * @prio: prio value (kernel-internal form)
3294 * This function changes the 'effective' priority of a task. It does
3295 * not touch ->normal_prio like __setscheduler().
3297 * Used by the rt_mutex code to implement priority inheritance
3298 * logic. Call site only calls if the priority of the task changed.
3300 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
3302 int oldprio
, queued
, running
, enqueue_flag
= 0;
3304 const struct sched_class
*prev_class
;
3306 BUG_ON(prio
> MAX_PRIO
);
3308 rq
= __task_rq_lock(p
);
3311 * Idle task boosting is a nono in general. There is one
3312 * exception, when PREEMPT_RT and NOHZ is active:
3314 * The idle task calls get_next_timer_interrupt() and holds
3315 * the timer wheel base->lock on the CPU and another CPU wants
3316 * to access the timer (probably to cancel it). We can safely
3317 * ignore the boosting request, as the idle CPU runs this code
3318 * with interrupts disabled and will complete the lock
3319 * protected section without being interrupted. So there is no
3320 * real need to boost.
3322 if (unlikely(p
== rq
->idle
)) {
3323 WARN_ON(p
!= rq
->curr
);
3324 WARN_ON(p
->pi_blocked_on
);
3328 trace_sched_pi_setprio(p
, prio
);
3330 prev_class
= p
->sched_class
;
3331 queued
= task_on_rq_queued(p
);
3332 running
= task_current(rq
, p
);
3334 dequeue_task(rq
, p
, 0);
3336 put_prev_task(rq
, p
);
3339 * Boosting condition are:
3340 * 1. -rt task is running and holds mutex A
3341 * --> -dl task blocks on mutex A
3343 * 2. -dl task is running and holds mutex A
3344 * --> -dl task blocks on mutex A and could preempt the
3347 if (dl_prio(prio
)) {
3348 struct task_struct
*pi_task
= rt_mutex_get_top_task(p
);
3349 if (!dl_prio(p
->normal_prio
) ||
3350 (pi_task
&& dl_entity_preempt(&pi_task
->dl
, &p
->dl
))) {
3351 p
->dl
.dl_boosted
= 1;
3352 enqueue_flag
= ENQUEUE_REPLENISH
;
3354 p
->dl
.dl_boosted
= 0;
3355 p
->sched_class
= &dl_sched_class
;
3356 } else if (rt_prio(prio
)) {
3357 if (dl_prio(oldprio
))
3358 p
->dl
.dl_boosted
= 0;
3360 enqueue_flag
= ENQUEUE_HEAD
;
3361 p
->sched_class
= &rt_sched_class
;
3363 if (dl_prio(oldprio
))
3364 p
->dl
.dl_boosted
= 0;
3365 if (rt_prio(oldprio
))
3367 p
->sched_class
= &fair_sched_class
;
3373 p
->sched_class
->set_curr_task(rq
);
3375 enqueue_task(rq
, p
, enqueue_flag
);
3377 check_class_changed(rq
, p
, prev_class
, oldprio
);
3379 preempt_disable(); /* avoid rq from going away on us */
3380 __task_rq_unlock(rq
);
3382 balance_callback(rq
);
3387 void set_user_nice(struct task_struct
*p
, long nice
)
3389 int old_prio
, delta
, queued
;
3390 unsigned long flags
;
3393 if (task_nice(p
) == nice
|| nice
< MIN_NICE
|| nice
> MAX_NICE
)
3396 * We have to be careful, if called from sys_setpriority(),
3397 * the task might be in the middle of scheduling on another CPU.
3399 rq
= task_rq_lock(p
, &flags
);
3401 * The RT priorities are set via sched_setscheduler(), but we still
3402 * allow the 'normal' nice value to be set - but as expected
3403 * it wont have any effect on scheduling until the task is
3404 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3406 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
3407 p
->static_prio
= NICE_TO_PRIO(nice
);
3410 queued
= task_on_rq_queued(p
);
3412 dequeue_task(rq
, p
, 0);
3414 p
->static_prio
= NICE_TO_PRIO(nice
);
3417 p
->prio
= effective_prio(p
);
3418 delta
= p
->prio
- old_prio
;
3421 enqueue_task(rq
, p
, 0);
3423 * If the task increased its priority or is running and
3424 * lowered its priority, then reschedule its CPU:
3426 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3430 task_rq_unlock(rq
, p
, &flags
);
3432 EXPORT_SYMBOL(set_user_nice
);
3435 * can_nice - check if a task can reduce its nice value
3439 int can_nice(const struct task_struct
*p
, const int nice
)
3441 /* convert nice value [19,-20] to rlimit style value [1,40] */
3442 int nice_rlim
= nice_to_rlimit(nice
);
3444 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3445 capable(CAP_SYS_NICE
));
3448 #ifdef __ARCH_WANT_SYS_NICE
3451 * sys_nice - change the priority of the current process.
3452 * @increment: priority increment
3454 * sys_setpriority is a more generic, but much slower function that
3455 * does similar things.
3457 SYSCALL_DEFINE1(nice
, int, increment
)
3462 * Setpriority might change our priority at the same moment.
3463 * We don't have to worry. Conceptually one call occurs first
3464 * and we have a single winner.
3466 increment
= clamp(increment
, -NICE_WIDTH
, NICE_WIDTH
);
3467 nice
= task_nice(current
) + increment
;
3469 nice
= clamp_val(nice
, MIN_NICE
, MAX_NICE
);
3470 if (increment
< 0 && !can_nice(current
, nice
))
3473 retval
= security_task_setnice(current
, nice
);
3477 set_user_nice(current
, nice
);
3484 * task_prio - return the priority value of a given task.
3485 * @p: the task in question.
3487 * Return: The priority value as seen by users in /proc.
3488 * RT tasks are offset by -200. Normal tasks are centered
3489 * around 0, value goes from -16 to +15.
3491 int task_prio(const struct task_struct
*p
)
3493 return p
->prio
- MAX_RT_PRIO
;
3497 * idle_cpu - is a given cpu idle currently?
3498 * @cpu: the processor in question.
3500 * Return: 1 if the CPU is currently idle. 0 otherwise.
3502 int idle_cpu(int cpu
)
3504 struct rq
*rq
= cpu_rq(cpu
);
3506 if (rq
->curr
!= rq
->idle
)
3513 if (!llist_empty(&rq
->wake_list
))
3521 * idle_task - return the idle task for a given cpu.
3522 * @cpu: the processor in question.
3524 * Return: The idle task for the cpu @cpu.
3526 struct task_struct
*idle_task(int cpu
)
3528 return cpu_rq(cpu
)->idle
;
3532 * find_process_by_pid - find a process with a matching PID value.
3533 * @pid: the pid in question.
3535 * The task of @pid, if found. %NULL otherwise.
3537 static struct task_struct
*find_process_by_pid(pid_t pid
)
3539 return pid
? find_task_by_vpid(pid
) : current
;
3543 * This function initializes the sched_dl_entity of a newly becoming
3544 * SCHED_DEADLINE task.
3546 * Only the static values are considered here, the actual runtime and the
3547 * absolute deadline will be properly calculated when the task is enqueued
3548 * for the first time with its new policy.
3551 __setparam_dl(struct task_struct
*p
, const struct sched_attr
*attr
)
3553 struct sched_dl_entity
*dl_se
= &p
->dl
;
3555 dl_se
->dl_runtime
= attr
->sched_runtime
;
3556 dl_se
->dl_deadline
= attr
->sched_deadline
;
3557 dl_se
->dl_period
= attr
->sched_period
?: dl_se
->dl_deadline
;
3558 dl_se
->flags
= attr
->sched_flags
;
3559 dl_se
->dl_bw
= to_ratio(dl_se
->dl_period
, dl_se
->dl_runtime
);
3562 * Changing the parameters of a task is 'tricky' and we're not doing
3563 * the correct thing -- also see task_dead_dl() and switched_from_dl().
3565 * What we SHOULD do is delay the bandwidth release until the 0-lag
3566 * point. This would include retaining the task_struct until that time
3567 * and change dl_overflow() to not immediately decrement the current
3570 * Instead we retain the current runtime/deadline and let the new
3571 * parameters take effect after the current reservation period lapses.
3572 * This is safe (albeit pessimistic) because the 0-lag point is always
3573 * before the current scheduling deadline.
3575 * We can still have temporary overloads because we do not delay the
3576 * change in bandwidth until that time; so admission control is
3577 * not on the safe side. It does however guarantee tasks will never
3578 * consume more than promised.
3583 * sched_setparam() passes in -1 for its policy, to let the functions
3584 * it calls know not to change it.
3586 #define SETPARAM_POLICY -1
3588 static void __setscheduler_params(struct task_struct
*p
,
3589 const struct sched_attr
*attr
)
3591 int policy
= attr
->sched_policy
;
3593 if (policy
== SETPARAM_POLICY
)
3598 if (dl_policy(policy
))
3599 __setparam_dl(p
, attr
);
3600 else if (fair_policy(policy
))
3601 p
->static_prio
= NICE_TO_PRIO(attr
->sched_nice
);
3604 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3605 * !rt_policy. Always setting this ensures that things like
3606 * getparam()/getattr() don't report silly values for !rt tasks.
3608 p
->rt_priority
= attr
->sched_priority
;
3609 p
->normal_prio
= normal_prio(p
);
3613 /* Actually do priority change: must hold pi & rq lock. */
3614 static void __setscheduler(struct rq
*rq
, struct task_struct
*p
,
3615 const struct sched_attr
*attr
, bool keep_boost
)
3617 __setscheduler_params(p
, attr
);
3620 * Keep a potential priority boosting if called from
3621 * sched_setscheduler().
3624 p
->prio
= rt_mutex_get_effective_prio(p
, normal_prio(p
));
3626 p
->prio
= normal_prio(p
);
3628 if (dl_prio(p
->prio
))
3629 p
->sched_class
= &dl_sched_class
;
3630 else if (rt_prio(p
->prio
))
3631 p
->sched_class
= &rt_sched_class
;
3633 p
->sched_class
= &fair_sched_class
;
3637 __getparam_dl(struct task_struct
*p
, struct sched_attr
*attr
)
3639 struct sched_dl_entity
*dl_se
= &p
->dl
;
3641 attr
->sched_priority
= p
->rt_priority
;
3642 attr
->sched_runtime
= dl_se
->dl_runtime
;
3643 attr
->sched_deadline
= dl_se
->dl_deadline
;
3644 attr
->sched_period
= dl_se
->dl_period
;
3645 attr
->sched_flags
= dl_se
->flags
;
3649 * This function validates the new parameters of a -deadline task.
3650 * We ask for the deadline not being zero, and greater or equal
3651 * than the runtime, as well as the period of being zero or
3652 * greater than deadline. Furthermore, we have to be sure that
3653 * user parameters are above the internal resolution of 1us (we
3654 * check sched_runtime only since it is always the smaller one) and
3655 * below 2^63 ns (we have to check both sched_deadline and
3656 * sched_period, as the latter can be zero).
3659 __checkparam_dl(const struct sched_attr
*attr
)
3662 if (attr
->sched_deadline
== 0)
3666 * Since we truncate DL_SCALE bits, make sure we're at least
3669 if (attr
->sched_runtime
< (1ULL << DL_SCALE
))
3673 * Since we use the MSB for wrap-around and sign issues, make
3674 * sure it's not set (mind that period can be equal to zero).
3676 if (attr
->sched_deadline
& (1ULL << 63) ||
3677 attr
->sched_period
& (1ULL << 63))
3680 /* runtime <= deadline <= period (if period != 0) */
3681 if ((attr
->sched_period
!= 0 &&
3682 attr
->sched_period
< attr
->sched_deadline
) ||
3683 attr
->sched_deadline
< attr
->sched_runtime
)
3690 * check the target process has a UID that matches the current process's
3692 static bool check_same_owner(struct task_struct
*p
)
3694 const struct cred
*cred
= current_cred(), *pcred
;
3698 pcred
= __task_cred(p
);
3699 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3700 uid_eq(cred
->euid
, pcred
->uid
));
3705 static bool dl_param_changed(struct task_struct
*p
,
3706 const struct sched_attr
*attr
)
3708 struct sched_dl_entity
*dl_se
= &p
->dl
;
3710 if (dl_se
->dl_runtime
!= attr
->sched_runtime
||
3711 dl_se
->dl_deadline
!= attr
->sched_deadline
||
3712 dl_se
->dl_period
!= attr
->sched_period
||
3713 dl_se
->flags
!= attr
->sched_flags
)
3719 static int __sched_setscheduler(struct task_struct
*p
,
3720 const struct sched_attr
*attr
,
3723 int newprio
= dl_policy(attr
->sched_policy
) ? MAX_DL_PRIO
- 1 :
3724 MAX_RT_PRIO
- 1 - attr
->sched_priority
;
3725 int retval
, oldprio
, oldpolicy
= -1, queued
, running
;
3726 int new_effective_prio
, policy
= attr
->sched_policy
;
3727 unsigned long flags
;
3728 const struct sched_class
*prev_class
;
3732 /* may grab non-irq protected spin_locks */
3733 BUG_ON(in_interrupt());
3735 /* double check policy once rq lock held */
3737 reset_on_fork
= p
->sched_reset_on_fork
;
3738 policy
= oldpolicy
= p
->policy
;
3740 reset_on_fork
= !!(attr
->sched_flags
& SCHED_FLAG_RESET_ON_FORK
);
3742 if (policy
!= SCHED_DEADLINE
&&
3743 policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3744 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3745 policy
!= SCHED_IDLE
)
3749 if (attr
->sched_flags
& ~(SCHED_FLAG_RESET_ON_FORK
))
3753 * Valid priorities for SCHED_FIFO and SCHED_RR are
3754 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3755 * SCHED_BATCH and SCHED_IDLE is 0.
3757 if ((p
->mm
&& attr
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3758 (!p
->mm
&& attr
->sched_priority
> MAX_RT_PRIO
-1))
3760 if ((dl_policy(policy
) && !__checkparam_dl(attr
)) ||
3761 (rt_policy(policy
) != (attr
->sched_priority
!= 0)))
3765 * Allow unprivileged RT tasks to decrease priority:
3767 if (user
&& !capable(CAP_SYS_NICE
)) {
3768 if (fair_policy(policy
)) {
3769 if (attr
->sched_nice
< task_nice(p
) &&
3770 !can_nice(p
, attr
->sched_nice
))
3774 if (rt_policy(policy
)) {
3775 unsigned long rlim_rtprio
=
3776 task_rlimit(p
, RLIMIT_RTPRIO
);
3778 /* can't set/change the rt policy */
3779 if (policy
!= p
->policy
&& !rlim_rtprio
)
3782 /* can't increase priority */
3783 if (attr
->sched_priority
> p
->rt_priority
&&
3784 attr
->sched_priority
> rlim_rtprio
)
3789 * Can't set/change SCHED_DEADLINE policy at all for now
3790 * (safest behavior); in the future we would like to allow
3791 * unprivileged DL tasks to increase their relative deadline
3792 * or reduce their runtime (both ways reducing utilization)
3794 if (dl_policy(policy
))
3798 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3799 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3801 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3802 if (!can_nice(p
, task_nice(p
)))
3806 /* can't change other user's priorities */
3807 if (!check_same_owner(p
))
3810 /* Normal users shall not reset the sched_reset_on_fork flag */
3811 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3816 retval
= security_task_setscheduler(p
);
3822 * make sure no PI-waiters arrive (or leave) while we are
3823 * changing the priority of the task:
3825 * To be able to change p->policy safely, the appropriate
3826 * runqueue lock must be held.
3828 rq
= task_rq_lock(p
, &flags
);
3831 * Changing the policy of the stop threads its a very bad idea
3833 if (p
== rq
->stop
) {
3834 task_rq_unlock(rq
, p
, &flags
);
3839 * If not changing anything there's no need to proceed further,
3840 * but store a possible modification of reset_on_fork.
3842 if (unlikely(policy
== p
->policy
)) {
3843 if (fair_policy(policy
) && attr
->sched_nice
!= task_nice(p
))
3845 if (rt_policy(policy
) && attr
->sched_priority
!= p
->rt_priority
)
3847 if (dl_policy(policy
) && dl_param_changed(p
, attr
))
3850 p
->sched_reset_on_fork
= reset_on_fork
;
3851 task_rq_unlock(rq
, p
, &flags
);
3857 #ifdef CONFIG_RT_GROUP_SCHED
3859 * Do not allow realtime tasks into groups that have no runtime
3862 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3863 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3864 !task_group_is_autogroup(task_group(p
))) {
3865 task_rq_unlock(rq
, p
, &flags
);
3870 if (dl_bandwidth_enabled() && dl_policy(policy
)) {
3871 cpumask_t
*span
= rq
->rd
->span
;
3874 * Don't allow tasks with an affinity mask smaller than
3875 * the entire root_domain to become SCHED_DEADLINE. We
3876 * will also fail if there's no bandwidth available.
3878 if (!cpumask_subset(span
, &p
->cpus_allowed
) ||
3879 rq
->rd
->dl_bw
.bw
== 0) {
3880 task_rq_unlock(rq
, p
, &flags
);
3887 /* recheck policy now with rq lock held */
3888 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3889 policy
= oldpolicy
= -1;
3890 task_rq_unlock(rq
, p
, &flags
);
3895 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3896 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3899 if ((dl_policy(policy
) || dl_task(p
)) && dl_overflow(p
, policy
, attr
)) {
3900 task_rq_unlock(rq
, p
, &flags
);
3904 p
->sched_reset_on_fork
= reset_on_fork
;
3909 * Take priority boosted tasks into account. If the new
3910 * effective priority is unchanged, we just store the new
3911 * normal parameters and do not touch the scheduler class and
3912 * the runqueue. This will be done when the task deboost
3915 new_effective_prio
= rt_mutex_get_effective_prio(p
, newprio
);
3916 if (new_effective_prio
== oldprio
) {
3917 __setscheduler_params(p
, attr
);
3918 task_rq_unlock(rq
, p
, &flags
);
3923 queued
= task_on_rq_queued(p
);
3924 running
= task_current(rq
, p
);
3926 dequeue_task(rq
, p
, 0);
3928 put_prev_task(rq
, p
);
3930 prev_class
= p
->sched_class
;
3931 __setscheduler(rq
, p
, attr
, pi
);
3934 p
->sched_class
->set_curr_task(rq
);
3937 * We enqueue to tail when the priority of a task is
3938 * increased (user space view).
3940 enqueue_task(rq
, p
, oldprio
<= p
->prio
? ENQUEUE_HEAD
: 0);
3943 check_class_changed(rq
, p
, prev_class
, oldprio
);
3944 preempt_disable(); /* avoid rq from going away on us */
3945 task_rq_unlock(rq
, p
, &flags
);
3948 rt_mutex_adjust_pi(p
);
3951 * Run balance callbacks after we've adjusted the PI chain.
3953 balance_callback(rq
);
3959 static int _sched_setscheduler(struct task_struct
*p
, int policy
,
3960 const struct sched_param
*param
, bool check
)
3962 struct sched_attr attr
= {
3963 .sched_policy
= policy
,
3964 .sched_priority
= param
->sched_priority
,
3965 .sched_nice
= PRIO_TO_NICE(p
->static_prio
),
3968 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
3969 if ((policy
!= SETPARAM_POLICY
) && (policy
& SCHED_RESET_ON_FORK
)) {
3970 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3971 policy
&= ~SCHED_RESET_ON_FORK
;
3972 attr
.sched_policy
= policy
;
3975 return __sched_setscheduler(p
, &attr
, check
, true);
3978 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3979 * @p: the task in question.
3980 * @policy: new policy.
3981 * @param: structure containing the new RT priority.
3983 * Return: 0 on success. An error code otherwise.
3985 * NOTE that the task may be already dead.
3987 int sched_setscheduler(struct task_struct
*p
, int policy
,
3988 const struct sched_param
*param
)
3990 return _sched_setscheduler(p
, policy
, param
, true);
3992 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3994 int sched_setattr(struct task_struct
*p
, const struct sched_attr
*attr
)
3996 return __sched_setscheduler(p
, attr
, true, true);
3998 EXPORT_SYMBOL_GPL(sched_setattr
);
4001 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4002 * @p: the task in question.
4003 * @policy: new policy.
4004 * @param: structure containing the new RT priority.
4006 * Just like sched_setscheduler, only don't bother checking if the
4007 * current context has permission. For example, this is needed in
4008 * stop_machine(): we create temporary high priority worker threads,
4009 * but our caller might not have that capability.
4011 * Return: 0 on success. An error code otherwise.
4013 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
4014 const struct sched_param
*param
)
4016 return _sched_setscheduler(p
, policy
, param
, false);
4020 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4022 struct sched_param lparam
;
4023 struct task_struct
*p
;
4026 if (!param
|| pid
< 0)
4028 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4033 p
= find_process_by_pid(pid
);
4035 retval
= sched_setscheduler(p
, policy
, &lparam
);
4042 * Mimics kernel/events/core.c perf_copy_attr().
4044 static int sched_copy_attr(struct sched_attr __user
*uattr
,
4045 struct sched_attr
*attr
)
4050 if (!access_ok(VERIFY_WRITE
, uattr
, SCHED_ATTR_SIZE_VER0
))
4054 * zero the full structure, so that a short copy will be nice.
4056 memset(attr
, 0, sizeof(*attr
));
4058 ret
= get_user(size
, &uattr
->size
);
4062 if (size
> PAGE_SIZE
) /* silly large */
4065 if (!size
) /* abi compat */
4066 size
= SCHED_ATTR_SIZE_VER0
;
4068 if (size
< SCHED_ATTR_SIZE_VER0
)
4072 * If we're handed a bigger struct than we know of,
4073 * ensure all the unknown bits are 0 - i.e. new
4074 * user-space does not rely on any kernel feature
4075 * extensions we dont know about yet.
4077 if (size
> sizeof(*attr
)) {
4078 unsigned char __user
*addr
;
4079 unsigned char __user
*end
;
4082 addr
= (void __user
*)uattr
+ sizeof(*attr
);
4083 end
= (void __user
*)uattr
+ size
;
4085 for (; addr
< end
; addr
++) {
4086 ret
= get_user(val
, addr
);
4092 size
= sizeof(*attr
);
4095 ret
= copy_from_user(attr
, uattr
, size
);
4100 * XXX: do we want to be lenient like existing syscalls; or do we want
4101 * to be strict and return an error on out-of-bounds values?
4103 attr
->sched_nice
= clamp(attr
->sched_nice
, MIN_NICE
, MAX_NICE
);
4108 put_user(sizeof(*attr
), &uattr
->size
);
4113 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4114 * @pid: the pid in question.
4115 * @policy: new policy.
4116 * @param: structure containing the new RT priority.
4118 * Return: 0 on success. An error code otherwise.
4120 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
4121 struct sched_param __user
*, param
)
4123 /* negative values for policy are not valid */
4127 return do_sched_setscheduler(pid
, policy
, param
);
4131 * sys_sched_setparam - set/change the RT priority of a thread
4132 * @pid: the pid in question.
4133 * @param: structure containing the new RT priority.
4135 * Return: 0 on success. An error code otherwise.
4137 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4139 return do_sched_setscheduler(pid
, SETPARAM_POLICY
, param
);
4143 * sys_sched_setattr - same as above, but with extended sched_attr
4144 * @pid: the pid in question.
4145 * @uattr: structure containing the extended parameters.
4146 * @flags: for future extension.
4148 SYSCALL_DEFINE3(sched_setattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
4149 unsigned int, flags
)
4151 struct sched_attr attr
;
4152 struct task_struct
*p
;
4155 if (!uattr
|| pid
< 0 || flags
)
4158 retval
= sched_copy_attr(uattr
, &attr
);
4162 if ((int)attr
.sched_policy
< 0)
4167 p
= find_process_by_pid(pid
);
4169 retval
= sched_setattr(p
, &attr
);
4176 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4177 * @pid: the pid in question.
4179 * Return: On success, the policy of the thread. Otherwise, a negative error
4182 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
4184 struct task_struct
*p
;
4192 p
= find_process_by_pid(pid
);
4194 retval
= security_task_getscheduler(p
);
4197 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
4204 * sys_sched_getparam - get the RT priority of a thread
4205 * @pid: the pid in question.
4206 * @param: structure containing the RT priority.
4208 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
4211 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4213 struct sched_param lp
= { .sched_priority
= 0 };
4214 struct task_struct
*p
;
4217 if (!param
|| pid
< 0)
4221 p
= find_process_by_pid(pid
);
4226 retval
= security_task_getscheduler(p
);
4230 if (task_has_rt_policy(p
))
4231 lp
.sched_priority
= p
->rt_priority
;
4235 * This one might sleep, we cannot do it with a spinlock held ...
4237 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4246 static int sched_read_attr(struct sched_attr __user
*uattr
,
4247 struct sched_attr
*attr
,
4252 if (!access_ok(VERIFY_WRITE
, uattr
, usize
))
4256 * If we're handed a smaller struct than we know of,
4257 * ensure all the unknown bits are 0 - i.e. old
4258 * user-space does not get uncomplete information.
4260 if (usize
< sizeof(*attr
)) {
4261 unsigned char *addr
;
4264 addr
= (void *)attr
+ usize
;
4265 end
= (void *)attr
+ sizeof(*attr
);
4267 for (; addr
< end
; addr
++) {
4275 ret
= copy_to_user(uattr
, attr
, attr
->size
);
4283 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
4284 * @pid: the pid in question.
4285 * @uattr: structure containing the extended parameters.
4286 * @size: sizeof(attr) for fwd/bwd comp.
4287 * @flags: for future extension.
4289 SYSCALL_DEFINE4(sched_getattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
4290 unsigned int, size
, unsigned int, flags
)
4292 struct sched_attr attr
= {
4293 .size
= sizeof(struct sched_attr
),
4295 struct task_struct
*p
;
4298 if (!uattr
|| pid
< 0 || size
> PAGE_SIZE
||
4299 size
< SCHED_ATTR_SIZE_VER0
|| flags
)
4303 p
= find_process_by_pid(pid
);
4308 retval
= security_task_getscheduler(p
);
4312 attr
.sched_policy
= p
->policy
;
4313 if (p
->sched_reset_on_fork
)
4314 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
4315 if (task_has_dl_policy(p
))
4316 __getparam_dl(p
, &attr
);
4317 else if (task_has_rt_policy(p
))
4318 attr
.sched_priority
= p
->rt_priority
;
4320 attr
.sched_nice
= task_nice(p
);
4324 retval
= sched_read_attr(uattr
, &attr
, size
);
4332 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4334 cpumask_var_t cpus_allowed
, new_mask
;
4335 struct task_struct
*p
;
4340 p
= find_process_by_pid(pid
);
4346 /* Prevent p going away */
4350 if (p
->flags
& PF_NO_SETAFFINITY
) {
4354 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4358 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4360 goto out_free_cpus_allowed
;
4363 if (!check_same_owner(p
)) {
4365 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
4367 goto out_free_new_mask
;
4372 retval
= security_task_setscheduler(p
);
4374 goto out_free_new_mask
;
4377 cpuset_cpus_allowed(p
, cpus_allowed
);
4378 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4381 * Since bandwidth control happens on root_domain basis,
4382 * if admission test is enabled, we only admit -deadline
4383 * tasks allowed to run on all the CPUs in the task's
4387 if (task_has_dl_policy(p
) && dl_bandwidth_enabled()) {
4389 if (!cpumask_subset(task_rq(p
)->rd
->span
, new_mask
)) {
4392 goto out_free_new_mask
;
4398 retval
= __set_cpus_allowed_ptr(p
, new_mask
, true);
4401 cpuset_cpus_allowed(p
, cpus_allowed
);
4402 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4404 * We must have raced with a concurrent cpuset
4405 * update. Just reset the cpus_allowed to the
4406 * cpuset's cpus_allowed
4408 cpumask_copy(new_mask
, cpus_allowed
);
4413 free_cpumask_var(new_mask
);
4414 out_free_cpus_allowed
:
4415 free_cpumask_var(cpus_allowed
);
4421 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4422 struct cpumask
*new_mask
)
4424 if (len
< cpumask_size())
4425 cpumask_clear(new_mask
);
4426 else if (len
> cpumask_size())
4427 len
= cpumask_size();
4429 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4433 * sys_sched_setaffinity - set the cpu affinity of a process
4434 * @pid: pid of the process
4435 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4436 * @user_mask_ptr: user-space pointer to the new cpu mask
4438 * Return: 0 on success. An error code otherwise.
4440 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4441 unsigned long __user
*, user_mask_ptr
)
4443 cpumask_var_t new_mask
;
4446 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4449 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4451 retval
= sched_setaffinity(pid
, new_mask
);
4452 free_cpumask_var(new_mask
);
4456 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4458 struct task_struct
*p
;
4459 unsigned long flags
;
4465 p
= find_process_by_pid(pid
);
4469 retval
= security_task_getscheduler(p
);
4473 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4474 cpumask_and(mask
, &p
->cpus_allowed
, cpu_active_mask
);
4475 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4484 * sys_sched_getaffinity - get the cpu affinity of a process
4485 * @pid: pid of the process
4486 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4487 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4489 * Return: 0 on success. An error code otherwise.
4491 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4492 unsigned long __user
*, user_mask_ptr
)
4497 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4499 if (len
& (sizeof(unsigned long)-1))
4502 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4505 ret
= sched_getaffinity(pid
, mask
);
4507 size_t retlen
= min_t(size_t, len
, cpumask_size());
4509 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4514 free_cpumask_var(mask
);
4520 * sys_sched_yield - yield the current processor to other threads.
4522 * This function yields the current CPU to other tasks. If there are no
4523 * other threads running on this CPU then this function will return.
4527 SYSCALL_DEFINE0(sched_yield
)
4529 struct rq
*rq
= this_rq_lock();
4531 schedstat_inc(rq
, yld_count
);
4532 current
->sched_class
->yield_task(rq
);
4535 * Since we are going to call schedule() anyway, there's
4536 * no need to preempt or enable interrupts:
4538 __release(rq
->lock
);
4539 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4540 do_raw_spin_unlock(&rq
->lock
);
4541 sched_preempt_enable_no_resched();
4548 int __sched
_cond_resched(void)
4550 if (should_resched(0)) {
4551 preempt_schedule_common();
4556 EXPORT_SYMBOL(_cond_resched
);
4559 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4560 * call schedule, and on return reacquire the lock.
4562 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4563 * operations here to prevent schedule() from being called twice (once via
4564 * spin_unlock(), once by hand).
4566 int __cond_resched_lock(spinlock_t
*lock
)
4568 int resched
= should_resched(PREEMPT_LOCK_OFFSET
);
4571 lockdep_assert_held(lock
);
4573 if (spin_needbreak(lock
) || resched
) {
4576 preempt_schedule_common();
4584 EXPORT_SYMBOL(__cond_resched_lock
);
4586 int __sched
__cond_resched_softirq(void)
4588 BUG_ON(!in_softirq());
4590 if (should_resched(SOFTIRQ_DISABLE_OFFSET
)) {
4592 preempt_schedule_common();
4598 EXPORT_SYMBOL(__cond_resched_softirq
);
4601 * yield - yield the current processor to other threads.
4603 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4605 * The scheduler is at all times free to pick the calling task as the most
4606 * eligible task to run, if removing the yield() call from your code breaks
4607 * it, its already broken.
4609 * Typical broken usage is:
4614 * where one assumes that yield() will let 'the other' process run that will
4615 * make event true. If the current task is a SCHED_FIFO task that will never
4616 * happen. Never use yield() as a progress guarantee!!
4618 * If you want to use yield() to wait for something, use wait_event().
4619 * If you want to use yield() to be 'nice' for others, use cond_resched().
4620 * If you still want to use yield(), do not!
4622 void __sched
yield(void)
4624 set_current_state(TASK_RUNNING
);
4627 EXPORT_SYMBOL(yield
);
4630 * yield_to - yield the current processor to another thread in
4631 * your thread group, or accelerate that thread toward the
4632 * processor it's on.
4634 * @preempt: whether task preemption is allowed or not
4636 * It's the caller's job to ensure that the target task struct
4637 * can't go away on us before we can do any checks.
4640 * true (>0) if we indeed boosted the target task.
4641 * false (0) if we failed to boost the target.
4642 * -ESRCH if there's no task to yield to.
4644 int __sched
yield_to(struct task_struct
*p
, bool preempt
)
4646 struct task_struct
*curr
= current
;
4647 struct rq
*rq
, *p_rq
;
4648 unsigned long flags
;
4651 local_irq_save(flags
);
4657 * If we're the only runnable task on the rq and target rq also
4658 * has only one task, there's absolutely no point in yielding.
4660 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
4665 double_rq_lock(rq
, p_rq
);
4666 if (task_rq(p
) != p_rq
) {
4667 double_rq_unlock(rq
, p_rq
);
4671 if (!curr
->sched_class
->yield_to_task
)
4674 if (curr
->sched_class
!= p
->sched_class
)
4677 if (task_running(p_rq
, p
) || p
->state
)
4680 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4682 schedstat_inc(rq
, yld_count
);
4684 * Make p's CPU reschedule; pick_next_entity takes care of
4687 if (preempt
&& rq
!= p_rq
)
4692 double_rq_unlock(rq
, p_rq
);
4694 local_irq_restore(flags
);
4701 EXPORT_SYMBOL_GPL(yield_to
);
4704 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4705 * that process accounting knows that this is a task in IO wait state.
4707 long __sched
io_schedule_timeout(long timeout
)
4709 int old_iowait
= current
->in_iowait
;
4713 current
->in_iowait
= 1;
4714 blk_schedule_flush_plug(current
);
4716 delayacct_blkio_start();
4718 atomic_inc(&rq
->nr_iowait
);
4719 ret
= schedule_timeout(timeout
);
4720 current
->in_iowait
= old_iowait
;
4721 atomic_dec(&rq
->nr_iowait
);
4722 delayacct_blkio_end();
4726 EXPORT_SYMBOL(io_schedule_timeout
);
4729 * sys_sched_get_priority_max - return maximum RT priority.
4730 * @policy: scheduling class.
4732 * Return: On success, this syscall returns the maximum
4733 * rt_priority that can be used by a given scheduling class.
4734 * On failure, a negative error code is returned.
4736 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4743 ret
= MAX_USER_RT_PRIO
-1;
4745 case SCHED_DEADLINE
:
4756 * sys_sched_get_priority_min - return minimum RT priority.
4757 * @policy: scheduling class.
4759 * Return: On success, this syscall returns the minimum
4760 * rt_priority that can be used by a given scheduling class.
4761 * On failure, a negative error code is returned.
4763 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4772 case SCHED_DEADLINE
:
4782 * sys_sched_rr_get_interval - return the default timeslice of a process.
4783 * @pid: pid of the process.
4784 * @interval: userspace pointer to the timeslice value.
4786 * this syscall writes the default timeslice value of a given process
4787 * into the user-space timespec buffer. A value of '0' means infinity.
4789 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4792 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4793 struct timespec __user
*, interval
)
4795 struct task_struct
*p
;
4796 unsigned int time_slice
;
4797 unsigned long flags
;
4807 p
= find_process_by_pid(pid
);
4811 retval
= security_task_getscheduler(p
);
4815 rq
= task_rq_lock(p
, &flags
);
4817 if (p
->sched_class
->get_rr_interval
)
4818 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4819 task_rq_unlock(rq
, p
, &flags
);
4822 jiffies_to_timespec(time_slice
, &t
);
4823 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4831 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4833 void sched_show_task(struct task_struct
*p
)
4835 unsigned long free
= 0;
4837 unsigned long state
= p
->state
;
4840 state
= __ffs(state
) + 1;
4841 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4842 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4843 #if BITS_PER_LONG == 32
4844 if (state
== TASK_RUNNING
)
4845 printk(KERN_CONT
" running ");
4847 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4849 if (state
== TASK_RUNNING
)
4850 printk(KERN_CONT
" running task ");
4852 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4854 #ifdef CONFIG_DEBUG_STACK_USAGE
4855 free
= stack_not_used(p
);
4860 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4862 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4863 task_pid_nr(p
), ppid
,
4864 (unsigned long)task_thread_info(p
)->flags
);
4866 print_worker_info(KERN_INFO
, p
);
4867 show_stack(p
, NULL
);
4870 void show_state_filter(unsigned long state_filter
)
4872 struct task_struct
*g
, *p
;
4874 #if BITS_PER_LONG == 32
4876 " task PC stack pid father\n");
4879 " task PC stack pid father\n");
4882 for_each_process_thread(g
, p
) {
4884 * reset the NMI-timeout, listing all files on a slow
4885 * console might take a lot of time:
4887 touch_nmi_watchdog();
4888 if (!state_filter
|| (p
->state
& state_filter
))
4892 touch_all_softlockup_watchdogs();
4894 #ifdef CONFIG_SCHED_DEBUG
4895 sysrq_sched_debug_show();
4899 * Only show locks if all tasks are dumped:
4902 debug_show_all_locks();
4905 void init_idle_bootup_task(struct task_struct
*idle
)
4907 idle
->sched_class
= &idle_sched_class
;
4911 * init_idle - set up an idle thread for a given CPU
4912 * @idle: task in question
4913 * @cpu: cpu the idle task belongs to
4915 * NOTE: this function does not set the idle thread's NEED_RESCHED
4916 * flag, to make booting more robust.
4918 void init_idle(struct task_struct
*idle
, int cpu
)
4920 struct rq
*rq
= cpu_rq(cpu
);
4921 unsigned long flags
;
4923 raw_spin_lock_irqsave(&idle
->pi_lock
, flags
);
4924 raw_spin_lock(&rq
->lock
);
4926 __sched_fork(0, idle
);
4927 idle
->state
= TASK_RUNNING
;
4928 idle
->se
.exec_start
= sched_clock();
4930 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4932 * We're having a chicken and egg problem, even though we are
4933 * holding rq->lock, the cpu isn't yet set to this cpu so the
4934 * lockdep check in task_group() will fail.
4936 * Similar case to sched_fork(). / Alternatively we could
4937 * use task_rq_lock() here and obtain the other rq->lock.
4942 __set_task_cpu(idle
, cpu
);
4945 rq
->curr
= rq
->idle
= idle
;
4946 idle
->on_rq
= TASK_ON_RQ_QUEUED
;
4947 #if defined(CONFIG_SMP)
4950 raw_spin_unlock(&rq
->lock
);
4951 raw_spin_unlock_irqrestore(&idle
->pi_lock
, flags
);
4953 /* Set the preempt count _outside_ the spinlocks! */
4954 init_idle_preempt_count(idle
, cpu
);
4957 * The idle tasks have their own, simple scheduling class:
4959 idle
->sched_class
= &idle_sched_class
;
4960 ftrace_graph_init_idle_task(idle
, cpu
);
4961 vtime_init_idle(idle
, cpu
);
4962 #if defined(CONFIG_SMP)
4963 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4967 int cpuset_cpumask_can_shrink(const struct cpumask
*cur
,
4968 const struct cpumask
*trial
)
4970 int ret
= 1, trial_cpus
;
4971 struct dl_bw
*cur_dl_b
;
4972 unsigned long flags
;
4974 if (!cpumask_weight(cur
))
4977 rcu_read_lock_sched();
4978 cur_dl_b
= dl_bw_of(cpumask_any(cur
));
4979 trial_cpus
= cpumask_weight(trial
);
4981 raw_spin_lock_irqsave(&cur_dl_b
->lock
, flags
);
4982 if (cur_dl_b
->bw
!= -1 &&
4983 cur_dl_b
->bw
* trial_cpus
< cur_dl_b
->total_bw
)
4985 raw_spin_unlock_irqrestore(&cur_dl_b
->lock
, flags
);
4986 rcu_read_unlock_sched();
4991 int task_can_attach(struct task_struct
*p
,
4992 const struct cpumask
*cs_cpus_allowed
)
4997 * Kthreads which disallow setaffinity shouldn't be moved
4998 * to a new cpuset; we don't want to change their cpu
4999 * affinity and isolating such threads by their set of
5000 * allowed nodes is unnecessary. Thus, cpusets are not
5001 * applicable for such threads. This prevents checking for
5002 * success of set_cpus_allowed_ptr() on all attached tasks
5003 * before cpus_allowed may be changed.
5005 if (p
->flags
& PF_NO_SETAFFINITY
) {
5011 if (dl_task(p
) && !cpumask_intersects(task_rq(p
)->rd
->span
,
5013 unsigned int dest_cpu
= cpumask_any_and(cpu_active_mask
,
5018 unsigned long flags
;
5020 rcu_read_lock_sched();
5021 dl_b
= dl_bw_of(dest_cpu
);
5022 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
5023 cpus
= dl_bw_cpus(dest_cpu
);
5024 overflow
= __dl_overflow(dl_b
, cpus
, 0, p
->dl
.dl_bw
);
5029 * We reserve space for this task in the destination
5030 * root_domain, as we can't fail after this point.
5031 * We will free resources in the source root_domain
5032 * later on (see set_cpus_allowed_dl()).
5034 __dl_add(dl_b
, p
->dl
.dl_bw
);
5036 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
5037 rcu_read_unlock_sched();
5047 #ifdef CONFIG_NUMA_BALANCING
5048 /* Migrate current task p to target_cpu */
5049 int migrate_task_to(struct task_struct
*p
, int target_cpu
)
5051 struct migration_arg arg
= { p
, target_cpu
};
5052 int curr_cpu
= task_cpu(p
);
5054 if (curr_cpu
== target_cpu
)
5057 if (!cpumask_test_cpu(target_cpu
, tsk_cpus_allowed(p
)))
5060 /* TODO: This is not properly updating schedstats */
5062 trace_sched_move_numa(p
, curr_cpu
, target_cpu
);
5063 return stop_one_cpu(curr_cpu
, migration_cpu_stop
, &arg
);
5067 * Requeue a task on a given node and accurately track the number of NUMA
5068 * tasks on the runqueues
5070 void sched_setnuma(struct task_struct
*p
, int nid
)
5073 unsigned long flags
;
5074 bool queued
, running
;
5076 rq
= task_rq_lock(p
, &flags
);
5077 queued
= task_on_rq_queued(p
);
5078 running
= task_current(rq
, p
);
5081 dequeue_task(rq
, p
, 0);
5083 put_prev_task(rq
, p
);
5085 p
->numa_preferred_nid
= nid
;
5088 p
->sched_class
->set_curr_task(rq
);
5090 enqueue_task(rq
, p
, 0);
5091 task_rq_unlock(rq
, p
, &flags
);
5093 #endif /* CONFIG_NUMA_BALANCING */
5095 #ifdef CONFIG_HOTPLUG_CPU
5097 * Ensures that the idle task is using init_mm right before its cpu goes
5100 void idle_task_exit(void)
5102 struct mm_struct
*mm
= current
->active_mm
;
5104 BUG_ON(cpu_online(smp_processor_id()));
5106 if (mm
!= &init_mm
) {
5107 switch_mm(mm
, &init_mm
, current
);
5108 finish_arch_post_lock_switch();
5114 * Since this CPU is going 'away' for a while, fold any nr_active delta
5115 * we might have. Assumes we're called after migrate_tasks() so that the
5116 * nr_active count is stable.
5118 * Also see the comment "Global load-average calculations".
5120 static void calc_load_migrate(struct rq
*rq
)
5122 long delta
= calc_load_fold_active(rq
);
5124 atomic_long_add(delta
, &calc_load_tasks
);
5127 static void put_prev_task_fake(struct rq
*rq
, struct task_struct
*prev
)
5131 static const struct sched_class fake_sched_class
= {
5132 .put_prev_task
= put_prev_task_fake
,
5135 static struct task_struct fake_task
= {
5137 * Avoid pull_{rt,dl}_task()
5139 .prio
= MAX_PRIO
+ 1,
5140 .sched_class
= &fake_sched_class
,
5144 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5145 * try_to_wake_up()->select_task_rq().
5147 * Called with rq->lock held even though we'er in stop_machine() and
5148 * there's no concurrency possible, we hold the required locks anyway
5149 * because of lock validation efforts.
5151 static void migrate_tasks(struct rq
*dead_rq
)
5153 struct rq
*rq
= dead_rq
;
5154 struct task_struct
*next
, *stop
= rq
->stop
;
5158 * Fudge the rq selection such that the below task selection loop
5159 * doesn't get stuck on the currently eligible stop task.
5161 * We're currently inside stop_machine() and the rq is either stuck
5162 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5163 * either way we should never end up calling schedule() until we're
5169 * put_prev_task() and pick_next_task() sched
5170 * class method both need to have an up-to-date
5171 * value of rq->clock[_task]
5173 update_rq_clock(rq
);
5177 * There's this thread running, bail when that's the only
5180 if (rq
->nr_running
== 1)
5184 * pick_next_task assumes pinned rq->lock.
5186 lockdep_pin_lock(&rq
->lock
);
5187 next
= pick_next_task(rq
, &fake_task
);
5189 next
->sched_class
->put_prev_task(rq
, next
);
5192 * Rules for changing task_struct::cpus_allowed are holding
5193 * both pi_lock and rq->lock, such that holding either
5194 * stabilizes the mask.
5196 * Drop rq->lock is not quite as disastrous as it usually is
5197 * because !cpu_active at this point, which means load-balance
5198 * will not interfere. Also, stop-machine.
5200 lockdep_unpin_lock(&rq
->lock
);
5201 raw_spin_unlock(&rq
->lock
);
5202 raw_spin_lock(&next
->pi_lock
);
5203 raw_spin_lock(&rq
->lock
);
5206 * Since we're inside stop-machine, _nothing_ should have
5207 * changed the task, WARN if weird stuff happened, because in
5208 * that case the above rq->lock drop is a fail too.
5210 if (WARN_ON(task_rq(next
) != rq
|| !task_on_rq_queued(next
))) {
5211 raw_spin_unlock(&next
->pi_lock
);
5215 /* Find suitable destination for @next, with force if needed. */
5216 dest_cpu
= select_fallback_rq(dead_rq
->cpu
, next
);
5218 rq
= __migrate_task(rq
, next
, dest_cpu
);
5219 if (rq
!= dead_rq
) {
5220 raw_spin_unlock(&rq
->lock
);
5222 raw_spin_lock(&rq
->lock
);
5224 raw_spin_unlock(&next
->pi_lock
);
5229 #endif /* CONFIG_HOTPLUG_CPU */
5231 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5233 static struct ctl_table sd_ctl_dir
[] = {
5235 .procname
= "sched_domain",
5241 static struct ctl_table sd_ctl_root
[] = {
5243 .procname
= "kernel",
5245 .child
= sd_ctl_dir
,
5250 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5252 struct ctl_table
*entry
=
5253 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5258 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5260 struct ctl_table
*entry
;
5263 * In the intermediate directories, both the child directory and
5264 * procname are dynamically allocated and could fail but the mode
5265 * will always be set. In the lowest directory the names are
5266 * static strings and all have proc handlers.
5268 for (entry
= *tablep
; entry
->mode
; entry
++) {
5270 sd_free_ctl_entry(&entry
->child
);
5271 if (entry
->proc_handler
== NULL
)
5272 kfree(entry
->procname
);
5279 static int min_load_idx
= 0;
5280 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
5283 set_table_entry(struct ctl_table
*entry
,
5284 const char *procname
, void *data
, int maxlen
,
5285 umode_t mode
, proc_handler
*proc_handler
,
5288 entry
->procname
= procname
;
5290 entry
->maxlen
= maxlen
;
5292 entry
->proc_handler
= proc_handler
;
5295 entry
->extra1
= &min_load_idx
;
5296 entry
->extra2
= &max_load_idx
;
5300 static struct ctl_table
*
5301 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5303 struct ctl_table
*table
= sd_alloc_ctl_entry(14);
5308 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5309 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5310 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5311 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5312 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5313 sizeof(int), 0644, proc_dointvec_minmax
, true);
5314 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5315 sizeof(int), 0644, proc_dointvec_minmax
, true);
5316 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5317 sizeof(int), 0644, proc_dointvec_minmax
, true);
5318 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5319 sizeof(int), 0644, proc_dointvec_minmax
, true);
5320 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5321 sizeof(int), 0644, proc_dointvec_minmax
, true);
5322 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5323 sizeof(int), 0644, proc_dointvec_minmax
, false);
5324 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5325 sizeof(int), 0644, proc_dointvec_minmax
, false);
5326 set_table_entry(&table
[9], "cache_nice_tries",
5327 &sd
->cache_nice_tries
,
5328 sizeof(int), 0644, proc_dointvec_minmax
, false);
5329 set_table_entry(&table
[10], "flags", &sd
->flags
,
5330 sizeof(int), 0644, proc_dointvec_minmax
, false);
5331 set_table_entry(&table
[11], "max_newidle_lb_cost",
5332 &sd
->max_newidle_lb_cost
,
5333 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5334 set_table_entry(&table
[12], "name", sd
->name
,
5335 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
5336 /* &table[13] is terminator */
5341 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5343 struct ctl_table
*entry
, *table
;
5344 struct sched_domain
*sd
;
5345 int domain_num
= 0, i
;
5348 for_each_domain(cpu
, sd
)
5350 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5355 for_each_domain(cpu
, sd
) {
5356 snprintf(buf
, 32, "domain%d", i
);
5357 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5359 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5366 static struct ctl_table_header
*sd_sysctl_header
;
5367 static void register_sched_domain_sysctl(void)
5369 int i
, cpu_num
= num_possible_cpus();
5370 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5373 WARN_ON(sd_ctl_dir
[0].child
);
5374 sd_ctl_dir
[0].child
= entry
;
5379 for_each_possible_cpu(i
) {
5380 snprintf(buf
, 32, "cpu%d", i
);
5381 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5383 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5387 WARN_ON(sd_sysctl_header
);
5388 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5391 /* may be called multiple times per register */
5392 static void unregister_sched_domain_sysctl(void)
5394 unregister_sysctl_table(sd_sysctl_header
);
5395 sd_sysctl_header
= NULL
;
5396 if (sd_ctl_dir
[0].child
)
5397 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5400 static void register_sched_domain_sysctl(void)
5403 static void unregister_sched_domain_sysctl(void)
5406 #endif /* CONFIG_SCHED_DEBUG && CONFIG_SYSCTL */
5408 static void set_rq_online(struct rq
*rq
)
5411 const struct sched_class
*class;
5413 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5416 for_each_class(class) {
5417 if (class->rq_online
)
5418 class->rq_online(rq
);
5423 static void set_rq_offline(struct rq
*rq
)
5426 const struct sched_class
*class;
5428 for_each_class(class) {
5429 if (class->rq_offline
)
5430 class->rq_offline(rq
);
5433 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5439 * migration_call - callback that gets triggered when a CPU is added.
5440 * Here we can start up the necessary migration thread for the new CPU.
5443 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5445 int cpu
= (long)hcpu
;
5446 unsigned long flags
;
5447 struct rq
*rq
= cpu_rq(cpu
);
5449 switch (action
& ~CPU_TASKS_FROZEN
) {
5451 case CPU_UP_PREPARE
:
5452 rq
->calc_load_update
= calc_load_update
;
5456 /* Update our root-domain */
5457 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5459 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5463 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5466 #ifdef CONFIG_HOTPLUG_CPU
5468 sched_ttwu_pending();
5469 /* Update our root-domain */
5470 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5472 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5476 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5477 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5481 calc_load_migrate(rq
);
5486 update_max_interval();
5492 * Register at high priority so that task migration (migrate_all_tasks)
5493 * happens before everything else. This has to be lower priority than
5494 * the notifier in the perf_event subsystem, though.
5496 static struct notifier_block migration_notifier
= {
5497 .notifier_call
= migration_call
,
5498 .priority
= CPU_PRI_MIGRATION
,
5501 static void set_cpu_rq_start_time(void)
5503 int cpu
= smp_processor_id();
5504 struct rq
*rq
= cpu_rq(cpu
);
5505 rq
->age_stamp
= sched_clock_cpu(cpu
);
5508 static int sched_cpu_active(struct notifier_block
*nfb
,
5509 unsigned long action
, void *hcpu
)
5511 switch (action
& ~CPU_TASKS_FROZEN
) {
5513 set_cpu_rq_start_time();
5517 * At this point a starting CPU has marked itself as online via
5518 * set_cpu_online(). But it might not yet have marked itself
5519 * as active, which is essential from here on.
5521 * Thus, fall-through and help the starting CPU along.
5523 case CPU_DOWN_FAILED
:
5524 set_cpu_active((long)hcpu
, true);
5531 static int sched_cpu_inactive(struct notifier_block
*nfb
,
5532 unsigned long action
, void *hcpu
)
5534 switch (action
& ~CPU_TASKS_FROZEN
) {
5535 case CPU_DOWN_PREPARE
:
5536 set_cpu_active((long)hcpu
, false);
5543 static int __init
migration_init(void)
5545 void *cpu
= (void *)(long)smp_processor_id();
5548 /* Initialize migration for the boot CPU */
5549 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5550 BUG_ON(err
== NOTIFY_BAD
);
5551 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5552 register_cpu_notifier(&migration_notifier
);
5554 /* Register cpu active notifiers */
5555 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5556 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5560 early_initcall(migration_init
);
5562 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5564 #ifdef CONFIG_SCHED_DEBUG
5566 static __read_mostly
int sched_debug_enabled
;
5568 static int __init
sched_debug_setup(char *str
)
5570 sched_debug_enabled
= 1;
5574 early_param("sched_debug", sched_debug_setup
);
5576 static inline bool sched_debug(void)
5578 return sched_debug_enabled
;
5581 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5582 struct cpumask
*groupmask
)
5584 struct sched_group
*group
= sd
->groups
;
5586 cpumask_clear(groupmask
);
5588 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5590 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5591 printk("does not load-balance\n");
5593 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5598 printk(KERN_CONT
"span %*pbl level %s\n",
5599 cpumask_pr_args(sched_domain_span(sd
)), sd
->name
);
5601 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5602 printk(KERN_ERR
"ERROR: domain->span does not contain "
5605 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5606 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5610 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5614 printk(KERN_ERR
"ERROR: group is NULL\n");
5618 if (!cpumask_weight(sched_group_cpus(group
))) {
5619 printk(KERN_CONT
"\n");
5620 printk(KERN_ERR
"ERROR: empty group\n");
5624 if (!(sd
->flags
& SD_OVERLAP
) &&
5625 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5626 printk(KERN_CONT
"\n");
5627 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5631 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5633 printk(KERN_CONT
" %*pbl",
5634 cpumask_pr_args(sched_group_cpus(group
)));
5635 if (group
->sgc
->capacity
!= SCHED_CAPACITY_SCALE
) {
5636 printk(KERN_CONT
" (cpu_capacity = %d)",
5637 group
->sgc
->capacity
);
5640 group
= group
->next
;
5641 } while (group
!= sd
->groups
);
5642 printk(KERN_CONT
"\n");
5644 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5645 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5648 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5649 printk(KERN_ERR
"ERROR: parent span is not a superset "
5650 "of domain->span\n");
5654 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5658 if (!sched_debug_enabled
)
5662 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5666 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5669 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5677 #else /* !CONFIG_SCHED_DEBUG */
5678 # define sched_domain_debug(sd, cpu) do { } while (0)
5679 static inline bool sched_debug(void)
5683 #endif /* CONFIG_SCHED_DEBUG */
5685 static int sd_degenerate(struct sched_domain
*sd
)
5687 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5690 /* Following flags need at least 2 groups */
5691 if (sd
->flags
& (SD_LOAD_BALANCE
|
5692 SD_BALANCE_NEWIDLE
|
5695 SD_SHARE_CPUCAPACITY
|
5696 SD_SHARE_PKG_RESOURCES
|
5697 SD_SHARE_POWERDOMAIN
)) {
5698 if (sd
->groups
!= sd
->groups
->next
)
5702 /* Following flags don't use groups */
5703 if (sd
->flags
& (SD_WAKE_AFFINE
))
5710 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5712 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5714 if (sd_degenerate(parent
))
5717 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5720 /* Flags needing groups don't count if only 1 group in parent */
5721 if (parent
->groups
== parent
->groups
->next
) {
5722 pflags
&= ~(SD_LOAD_BALANCE
|
5723 SD_BALANCE_NEWIDLE
|
5726 SD_SHARE_CPUCAPACITY
|
5727 SD_SHARE_PKG_RESOURCES
|
5729 SD_SHARE_POWERDOMAIN
);
5730 if (nr_node_ids
== 1)
5731 pflags
&= ~SD_SERIALIZE
;
5733 if (~cflags
& pflags
)
5739 static void free_rootdomain(struct rcu_head
*rcu
)
5741 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5743 cpupri_cleanup(&rd
->cpupri
);
5744 cpudl_cleanup(&rd
->cpudl
);
5745 free_cpumask_var(rd
->dlo_mask
);
5746 free_cpumask_var(rd
->rto_mask
);
5747 free_cpumask_var(rd
->online
);
5748 free_cpumask_var(rd
->span
);
5752 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5754 struct root_domain
*old_rd
= NULL
;
5755 unsigned long flags
;
5757 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5762 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5765 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5768 * If we dont want to free the old_rd yet then
5769 * set old_rd to NULL to skip the freeing later
5772 if (!atomic_dec_and_test(&old_rd
->refcount
))
5776 atomic_inc(&rd
->refcount
);
5779 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5780 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5783 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5786 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5789 static int init_rootdomain(struct root_domain
*rd
)
5791 memset(rd
, 0, sizeof(*rd
));
5793 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5795 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5797 if (!alloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
5799 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5802 init_dl_bw(&rd
->dl_bw
);
5803 if (cpudl_init(&rd
->cpudl
) != 0)
5806 if (cpupri_init(&rd
->cpupri
) != 0)
5811 free_cpumask_var(rd
->rto_mask
);
5813 free_cpumask_var(rd
->dlo_mask
);
5815 free_cpumask_var(rd
->online
);
5817 free_cpumask_var(rd
->span
);
5823 * By default the system creates a single root-domain with all cpus as
5824 * members (mimicking the global state we have today).
5826 struct root_domain def_root_domain
;
5828 static void init_defrootdomain(void)
5830 init_rootdomain(&def_root_domain
);
5832 atomic_set(&def_root_domain
.refcount
, 1);
5835 static struct root_domain
*alloc_rootdomain(void)
5837 struct root_domain
*rd
;
5839 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5843 if (init_rootdomain(rd
) != 0) {
5851 static void free_sched_groups(struct sched_group
*sg
, int free_sgc
)
5853 struct sched_group
*tmp
, *first
;
5862 if (free_sgc
&& atomic_dec_and_test(&sg
->sgc
->ref
))
5867 } while (sg
!= first
);
5870 static void free_sched_domain(struct rcu_head
*rcu
)
5872 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5875 * If its an overlapping domain it has private groups, iterate and
5878 if (sd
->flags
& SD_OVERLAP
) {
5879 free_sched_groups(sd
->groups
, 1);
5880 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5881 kfree(sd
->groups
->sgc
);
5887 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5889 call_rcu(&sd
->rcu
, free_sched_domain
);
5892 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5894 for (; sd
; sd
= sd
->parent
)
5895 destroy_sched_domain(sd
, cpu
);
5899 * Keep a special pointer to the highest sched_domain that has
5900 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5901 * allows us to avoid some pointer chasing select_idle_sibling().
5903 * Also keep a unique ID per domain (we use the first cpu number in
5904 * the cpumask of the domain), this allows us to quickly tell if
5905 * two cpus are in the same cache domain, see cpus_share_cache().
5907 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5908 DEFINE_PER_CPU(int, sd_llc_size
);
5909 DEFINE_PER_CPU(int, sd_llc_id
);
5910 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
5911 DEFINE_PER_CPU(struct sched_domain
*, sd_busy
);
5912 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
5914 static void update_top_cache_domain(int cpu
)
5916 struct sched_domain
*sd
;
5917 struct sched_domain
*busy_sd
= NULL
;
5921 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5923 id
= cpumask_first(sched_domain_span(sd
));
5924 size
= cpumask_weight(sched_domain_span(sd
));
5925 busy_sd
= sd
->parent
; /* sd_busy */
5927 rcu_assign_pointer(per_cpu(sd_busy
, cpu
), busy_sd
);
5929 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5930 per_cpu(sd_llc_size
, cpu
) = size
;
5931 per_cpu(sd_llc_id
, cpu
) = id
;
5933 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
5934 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
5936 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
5937 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
5941 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5942 * hold the hotplug lock.
5945 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5947 struct rq
*rq
= cpu_rq(cpu
);
5948 struct sched_domain
*tmp
;
5950 /* Remove the sched domains which do not contribute to scheduling. */
5951 for (tmp
= sd
; tmp
; ) {
5952 struct sched_domain
*parent
= tmp
->parent
;
5956 if (sd_parent_degenerate(tmp
, parent
)) {
5957 tmp
->parent
= parent
->parent
;
5959 parent
->parent
->child
= tmp
;
5961 * Transfer SD_PREFER_SIBLING down in case of a
5962 * degenerate parent; the spans match for this
5963 * so the property transfers.
5965 if (parent
->flags
& SD_PREFER_SIBLING
)
5966 tmp
->flags
|= SD_PREFER_SIBLING
;
5967 destroy_sched_domain(parent
, cpu
);
5972 if (sd
&& sd_degenerate(sd
)) {
5975 destroy_sched_domain(tmp
, cpu
);
5980 sched_domain_debug(sd
, cpu
);
5982 rq_attach_root(rq
, rd
);
5984 rcu_assign_pointer(rq
->sd
, sd
);
5985 destroy_sched_domains(tmp
, cpu
);
5987 update_top_cache_domain(cpu
);
5990 /* Setup the mask of cpus configured for isolated domains */
5991 static int __init
isolated_cpu_setup(char *str
)
5993 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5994 cpulist_parse(str
, cpu_isolated_map
);
5998 __setup("isolcpus=", isolated_cpu_setup
);
6001 struct sched_domain
** __percpu sd
;
6002 struct root_domain
*rd
;
6013 * Build an iteration mask that can exclude certain CPUs from the upwards
6016 * Asymmetric node setups can result in situations where the domain tree is of
6017 * unequal depth, make sure to skip domains that already cover the entire
6020 * In that case build_sched_domains() will have terminated the iteration early
6021 * and our sibling sd spans will be empty. Domains should always include the
6022 * cpu they're built on, so check that.
6025 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
6027 const struct cpumask
*span
= sched_domain_span(sd
);
6028 struct sd_data
*sdd
= sd
->private;
6029 struct sched_domain
*sibling
;
6032 for_each_cpu(i
, span
) {
6033 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
6034 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
6037 cpumask_set_cpu(i
, sched_group_mask(sg
));
6042 * Return the canonical balance cpu for this group, this is the first cpu
6043 * of this group that's also in the iteration mask.
6045 int group_balance_cpu(struct sched_group
*sg
)
6047 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
6051 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
6053 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
6054 const struct cpumask
*span
= sched_domain_span(sd
);
6055 struct cpumask
*covered
= sched_domains_tmpmask
;
6056 struct sd_data
*sdd
= sd
->private;
6057 struct sched_domain
*sibling
;
6060 cpumask_clear(covered
);
6062 for_each_cpu(i
, span
) {
6063 struct cpumask
*sg_span
;
6065 if (cpumask_test_cpu(i
, covered
))
6068 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
6070 /* See the comment near build_group_mask(). */
6071 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
6074 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6075 GFP_KERNEL
, cpu_to_node(cpu
));
6080 sg_span
= sched_group_cpus(sg
);
6082 cpumask_copy(sg_span
, sched_domain_span(sibling
->child
));
6084 cpumask_set_cpu(i
, sg_span
);
6086 cpumask_or(covered
, covered
, sg_span
);
6088 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, i
);
6089 if (atomic_inc_return(&sg
->sgc
->ref
) == 1)
6090 build_group_mask(sd
, sg
);
6093 * Initialize sgc->capacity such that even if we mess up the
6094 * domains and no possible iteration will get us here, we won't
6097 sg
->sgc
->capacity
= SCHED_CAPACITY_SCALE
* cpumask_weight(sg_span
);
6100 * Make sure the first group of this domain contains the
6101 * canonical balance cpu. Otherwise the sched_domain iteration
6102 * breaks. See update_sg_lb_stats().
6104 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
6105 group_balance_cpu(sg
) == cpu
)
6115 sd
->groups
= groups
;
6120 free_sched_groups(first
, 0);
6125 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
6127 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
6128 struct sched_domain
*child
= sd
->child
;
6131 cpu
= cpumask_first(sched_domain_span(child
));
6134 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
6135 (*sg
)->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
6136 atomic_set(&(*sg
)->sgc
->ref
, 1); /* for claim_allocations */
6143 * build_sched_groups will build a circular linked list of the groups
6144 * covered by the given span, and will set each group's ->cpumask correctly,
6145 * and ->cpu_capacity to 0.
6147 * Assumes the sched_domain tree is fully constructed
6150 build_sched_groups(struct sched_domain
*sd
, int cpu
)
6152 struct sched_group
*first
= NULL
, *last
= NULL
;
6153 struct sd_data
*sdd
= sd
->private;
6154 const struct cpumask
*span
= sched_domain_span(sd
);
6155 struct cpumask
*covered
;
6158 get_group(cpu
, sdd
, &sd
->groups
);
6159 atomic_inc(&sd
->groups
->ref
);
6161 if (cpu
!= cpumask_first(span
))
6164 lockdep_assert_held(&sched_domains_mutex
);
6165 covered
= sched_domains_tmpmask
;
6167 cpumask_clear(covered
);
6169 for_each_cpu(i
, span
) {
6170 struct sched_group
*sg
;
6173 if (cpumask_test_cpu(i
, covered
))
6176 group
= get_group(i
, sdd
, &sg
);
6177 cpumask_setall(sched_group_mask(sg
));
6179 for_each_cpu(j
, span
) {
6180 if (get_group(j
, sdd
, NULL
) != group
)
6183 cpumask_set_cpu(j
, covered
);
6184 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6199 * Initialize sched groups cpu_capacity.
6201 * cpu_capacity indicates the capacity of sched group, which is used while
6202 * distributing the load between different sched groups in a sched domain.
6203 * Typically cpu_capacity for all the groups in a sched domain will be same
6204 * unless there are asymmetries in the topology. If there are asymmetries,
6205 * group having more cpu_capacity will pickup more load compared to the
6206 * group having less cpu_capacity.
6208 static void init_sched_groups_capacity(int cpu
, struct sched_domain
*sd
)
6210 struct sched_group
*sg
= sd
->groups
;
6215 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
6217 } while (sg
!= sd
->groups
);
6219 if (cpu
!= group_balance_cpu(sg
))
6222 update_group_capacity(sd
, cpu
);
6223 atomic_set(&sg
->sgc
->nr_busy_cpus
, sg
->group_weight
);
6227 * Initializers for schedule domains
6228 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6231 static int default_relax_domain_level
= -1;
6232 int sched_domain_level_max
;
6234 static int __init
setup_relax_domain_level(char *str
)
6236 if (kstrtoint(str
, 0, &default_relax_domain_level
))
6237 pr_warn("Unable to set relax_domain_level\n");
6241 __setup("relax_domain_level=", setup_relax_domain_level
);
6243 static void set_domain_attribute(struct sched_domain
*sd
,
6244 struct sched_domain_attr
*attr
)
6248 if (!attr
|| attr
->relax_domain_level
< 0) {
6249 if (default_relax_domain_level
< 0)
6252 request
= default_relax_domain_level
;
6254 request
= attr
->relax_domain_level
;
6255 if (request
< sd
->level
) {
6256 /* turn off idle balance on this domain */
6257 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6259 /* turn on idle balance on this domain */
6260 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6264 static void __sdt_free(const struct cpumask
*cpu_map
);
6265 static int __sdt_alloc(const struct cpumask
*cpu_map
);
6267 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6268 const struct cpumask
*cpu_map
)
6272 if (!atomic_read(&d
->rd
->refcount
))
6273 free_rootdomain(&d
->rd
->rcu
); /* fall through */
6275 free_percpu(d
->sd
); /* fall through */
6277 __sdt_free(cpu_map
); /* fall through */
6283 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6284 const struct cpumask
*cpu_map
)
6286 memset(d
, 0, sizeof(*d
));
6288 if (__sdt_alloc(cpu_map
))
6289 return sa_sd_storage
;
6290 d
->sd
= alloc_percpu(struct sched_domain
*);
6292 return sa_sd_storage
;
6293 d
->rd
= alloc_rootdomain();
6296 return sa_rootdomain
;
6300 * NULL the sd_data elements we've used to build the sched_domain and
6301 * sched_group structure so that the subsequent __free_domain_allocs()
6302 * will not free the data we're using.
6304 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
6306 struct sd_data
*sdd
= sd
->private;
6308 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
6309 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
6311 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
6312 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
6314 if (atomic_read(&(*per_cpu_ptr(sdd
->sgc
, cpu
))->ref
))
6315 *per_cpu_ptr(sdd
->sgc
, cpu
) = NULL
;
6319 static int sched_domains_numa_levels
;
6320 enum numa_topology_type sched_numa_topology_type
;
6321 static int *sched_domains_numa_distance
;
6322 int sched_max_numa_distance
;
6323 static struct cpumask
***sched_domains_numa_masks
;
6324 static int sched_domains_curr_level
;
6328 * SD_flags allowed in topology descriptions.
6330 * SD_SHARE_CPUCAPACITY - describes SMT topologies
6331 * SD_SHARE_PKG_RESOURCES - describes shared caches
6332 * SD_NUMA - describes NUMA topologies
6333 * SD_SHARE_POWERDOMAIN - describes shared power domain
6336 * SD_ASYM_PACKING - describes SMT quirks
6338 #define TOPOLOGY_SD_FLAGS \
6339 (SD_SHARE_CPUCAPACITY | \
6340 SD_SHARE_PKG_RESOURCES | \
6343 SD_SHARE_POWERDOMAIN)
6345 static struct sched_domain
*
6346 sd_init(struct sched_domain_topology_level
*tl
, int cpu
)
6348 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
6349 int sd_weight
, sd_flags
= 0;
6353 * Ugly hack to pass state to sd_numa_mask()...
6355 sched_domains_curr_level
= tl
->numa_level
;
6358 sd_weight
= cpumask_weight(tl
->mask(cpu
));
6361 sd_flags
= (*tl
->sd_flags
)();
6362 if (WARN_ONCE(sd_flags
& ~TOPOLOGY_SD_FLAGS
,
6363 "wrong sd_flags in topology description\n"))
6364 sd_flags
&= ~TOPOLOGY_SD_FLAGS
;
6366 *sd
= (struct sched_domain
){
6367 .min_interval
= sd_weight
,
6368 .max_interval
= 2*sd_weight
,
6370 .imbalance_pct
= 125,
6372 .cache_nice_tries
= 0,
6379 .flags
= 1*SD_LOAD_BALANCE
6380 | 1*SD_BALANCE_NEWIDLE
6385 | 0*SD_SHARE_CPUCAPACITY
6386 | 0*SD_SHARE_PKG_RESOURCES
6388 | 0*SD_PREFER_SIBLING
6393 .last_balance
= jiffies
,
6394 .balance_interval
= sd_weight
,
6396 .max_newidle_lb_cost
= 0,
6397 .next_decay_max_lb_cost
= jiffies
,
6398 #ifdef CONFIG_SCHED_DEBUG
6404 * Convert topological properties into behaviour.
6407 if (sd
->flags
& SD_SHARE_CPUCAPACITY
) {
6408 sd
->flags
|= SD_PREFER_SIBLING
;
6409 sd
->imbalance_pct
= 110;
6410 sd
->smt_gain
= 1178; /* ~15% */
6412 } else if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
6413 sd
->imbalance_pct
= 117;
6414 sd
->cache_nice_tries
= 1;
6418 } else if (sd
->flags
& SD_NUMA
) {
6419 sd
->cache_nice_tries
= 2;
6423 sd
->flags
|= SD_SERIALIZE
;
6424 if (sched_domains_numa_distance
[tl
->numa_level
] > RECLAIM_DISTANCE
) {
6425 sd
->flags
&= ~(SD_BALANCE_EXEC
|
6432 sd
->flags
|= SD_PREFER_SIBLING
;
6433 sd
->cache_nice_tries
= 1;
6438 sd
->private = &tl
->data
;
6444 * Topology list, bottom-up.
6446 static struct sched_domain_topology_level default_topology
[] = {
6447 #ifdef CONFIG_SCHED_SMT
6448 { cpu_smt_mask
, cpu_smt_flags
, SD_INIT_NAME(SMT
) },
6450 #ifdef CONFIG_SCHED_MC
6451 { cpu_coregroup_mask
, cpu_core_flags
, SD_INIT_NAME(MC
) },
6453 { cpu_cpu_mask
, SD_INIT_NAME(DIE
) },
6457 struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6459 #define for_each_sd_topology(tl) \
6460 for (tl = sched_domain_topology; tl->mask; tl++)
6462 void set_sched_topology(struct sched_domain_topology_level
*tl
)
6464 sched_domain_topology
= tl
;
6469 static const struct cpumask
*sd_numa_mask(int cpu
)
6471 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6474 static void sched_numa_warn(const char *str
)
6476 static int done
= false;
6484 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6486 for (i
= 0; i
< nr_node_ids
; i
++) {
6487 printk(KERN_WARNING
" ");
6488 for (j
= 0; j
< nr_node_ids
; j
++)
6489 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6490 printk(KERN_CONT
"\n");
6492 printk(KERN_WARNING
"\n");
6495 bool find_numa_distance(int distance
)
6499 if (distance
== node_distance(0, 0))
6502 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6503 if (sched_domains_numa_distance
[i
] == distance
)
6511 * A system can have three types of NUMA topology:
6512 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
6513 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
6514 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
6516 * The difference between a glueless mesh topology and a backplane
6517 * topology lies in whether communication between not directly
6518 * connected nodes goes through intermediary nodes (where programs
6519 * could run), or through backplane controllers. This affects
6520 * placement of programs.
6522 * The type of topology can be discerned with the following tests:
6523 * - If the maximum distance between any nodes is 1 hop, the system
6524 * is directly connected.
6525 * - If for two nodes A and B, located N > 1 hops away from each other,
6526 * there is an intermediary node C, which is < N hops away from both
6527 * nodes A and B, the system is a glueless mesh.
6529 static void init_numa_topology_type(void)
6533 n
= sched_max_numa_distance
;
6535 if (sched_domains_numa_levels
<= 1) {
6536 sched_numa_topology_type
= NUMA_DIRECT
;
6540 for_each_online_node(a
) {
6541 for_each_online_node(b
) {
6542 /* Find two nodes furthest removed from each other. */
6543 if (node_distance(a
, b
) < n
)
6546 /* Is there an intermediary node between a and b? */
6547 for_each_online_node(c
) {
6548 if (node_distance(a
, c
) < n
&&
6549 node_distance(b
, c
) < n
) {
6550 sched_numa_topology_type
=
6556 sched_numa_topology_type
= NUMA_BACKPLANE
;
6562 static void sched_init_numa(void)
6564 int next_distance
, curr_distance
= node_distance(0, 0);
6565 struct sched_domain_topology_level
*tl
;
6569 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6570 if (!sched_domains_numa_distance
)
6574 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6575 * unique distances in the node_distance() table.
6577 * Assumes node_distance(0,j) includes all distances in
6578 * node_distance(i,j) in order to avoid cubic time.
6580 next_distance
= curr_distance
;
6581 for (i
= 0; i
< nr_node_ids
; i
++) {
6582 for (j
= 0; j
< nr_node_ids
; j
++) {
6583 for (k
= 0; k
< nr_node_ids
; k
++) {
6584 int distance
= node_distance(i
, k
);
6586 if (distance
> curr_distance
&&
6587 (distance
< next_distance
||
6588 next_distance
== curr_distance
))
6589 next_distance
= distance
;
6592 * While not a strong assumption it would be nice to know
6593 * about cases where if node A is connected to B, B is not
6594 * equally connected to A.
6596 if (sched_debug() && node_distance(k
, i
) != distance
)
6597 sched_numa_warn("Node-distance not symmetric");
6599 if (sched_debug() && i
&& !find_numa_distance(distance
))
6600 sched_numa_warn("Node-0 not representative");
6602 if (next_distance
!= curr_distance
) {
6603 sched_domains_numa_distance
[level
++] = next_distance
;
6604 sched_domains_numa_levels
= level
;
6605 curr_distance
= next_distance
;
6610 * In case of sched_debug() we verify the above assumption.
6620 * 'level' contains the number of unique distances, excluding the
6621 * identity distance node_distance(i,i).
6623 * The sched_domains_numa_distance[] array includes the actual distance
6628 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6629 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6630 * the array will contain less then 'level' members. This could be
6631 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6632 * in other functions.
6634 * We reset it to 'level' at the end of this function.
6636 sched_domains_numa_levels
= 0;
6638 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6639 if (!sched_domains_numa_masks
)
6643 * Now for each level, construct a mask per node which contains all
6644 * cpus of nodes that are that many hops away from us.
6646 for (i
= 0; i
< level
; i
++) {
6647 sched_domains_numa_masks
[i
] =
6648 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6649 if (!sched_domains_numa_masks
[i
])
6652 for (j
= 0; j
< nr_node_ids
; j
++) {
6653 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6657 sched_domains_numa_masks
[i
][j
] = mask
;
6659 for (k
= 0; k
< nr_node_ids
; k
++) {
6660 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6663 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6668 /* Compute default topology size */
6669 for (i
= 0; sched_domain_topology
[i
].mask
; i
++);
6671 tl
= kzalloc((i
+ level
+ 1) *
6672 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6677 * Copy the default topology bits..
6679 for (i
= 0; sched_domain_topology
[i
].mask
; i
++)
6680 tl
[i
] = sched_domain_topology
[i
];
6683 * .. and append 'j' levels of NUMA goodness.
6685 for (j
= 0; j
< level
; i
++, j
++) {
6686 tl
[i
] = (struct sched_domain_topology_level
){
6687 .mask
= sd_numa_mask
,
6688 .sd_flags
= cpu_numa_flags
,
6689 .flags
= SDTL_OVERLAP
,
6695 sched_domain_topology
= tl
;
6697 sched_domains_numa_levels
= level
;
6698 sched_max_numa_distance
= sched_domains_numa_distance
[level
- 1];
6700 init_numa_topology_type();
6703 static void sched_domains_numa_masks_set(int cpu
)
6706 int node
= cpu_to_node(cpu
);
6708 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6709 for (j
= 0; j
< nr_node_ids
; j
++) {
6710 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6711 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6716 static void sched_domains_numa_masks_clear(int cpu
)
6719 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6720 for (j
= 0; j
< nr_node_ids
; j
++)
6721 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6726 * Update sched_domains_numa_masks[level][node] array when new cpus
6729 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6730 unsigned long action
,
6733 int cpu
= (long)hcpu
;
6735 switch (action
& ~CPU_TASKS_FROZEN
) {
6737 sched_domains_numa_masks_set(cpu
);
6741 sched_domains_numa_masks_clear(cpu
);
6751 static inline void sched_init_numa(void)
6755 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6756 unsigned long action
,
6761 #endif /* CONFIG_NUMA */
6763 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6765 struct sched_domain_topology_level
*tl
;
6768 for_each_sd_topology(tl
) {
6769 struct sd_data
*sdd
= &tl
->data
;
6771 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6775 sdd
->sg
= alloc_percpu(struct sched_group
*);
6779 sdd
->sgc
= alloc_percpu(struct sched_group_capacity
*);
6783 for_each_cpu(j
, cpu_map
) {
6784 struct sched_domain
*sd
;
6785 struct sched_group
*sg
;
6786 struct sched_group_capacity
*sgc
;
6788 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6789 GFP_KERNEL
, cpu_to_node(j
));
6793 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6795 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6796 GFP_KERNEL
, cpu_to_node(j
));
6802 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6804 sgc
= kzalloc_node(sizeof(struct sched_group_capacity
) + cpumask_size(),
6805 GFP_KERNEL
, cpu_to_node(j
));
6809 *per_cpu_ptr(sdd
->sgc
, j
) = sgc
;
6816 static void __sdt_free(const struct cpumask
*cpu_map
)
6818 struct sched_domain_topology_level
*tl
;
6821 for_each_sd_topology(tl
) {
6822 struct sd_data
*sdd
= &tl
->data
;
6824 for_each_cpu(j
, cpu_map
) {
6825 struct sched_domain
*sd
;
6828 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6829 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6830 free_sched_groups(sd
->groups
, 0);
6831 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6835 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6837 kfree(*per_cpu_ptr(sdd
->sgc
, j
));
6839 free_percpu(sdd
->sd
);
6841 free_percpu(sdd
->sg
);
6843 free_percpu(sdd
->sgc
);
6848 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6849 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6850 struct sched_domain
*child
, int cpu
)
6852 struct sched_domain
*sd
= sd_init(tl
, cpu
);
6856 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6858 sd
->level
= child
->level
+ 1;
6859 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6863 if (!cpumask_subset(sched_domain_span(child
),
6864 sched_domain_span(sd
))) {
6865 pr_err("BUG: arch topology borken\n");
6866 #ifdef CONFIG_SCHED_DEBUG
6867 pr_err(" the %s domain not a subset of the %s domain\n",
6868 child
->name
, sd
->name
);
6870 /* Fixup, ensure @sd has at least @child cpus. */
6871 cpumask_or(sched_domain_span(sd
),
6872 sched_domain_span(sd
),
6873 sched_domain_span(child
));
6877 set_domain_attribute(sd
, attr
);
6883 * Build sched domains for a given set of cpus and attach the sched domains
6884 * to the individual cpus
6886 static int build_sched_domains(const struct cpumask
*cpu_map
,
6887 struct sched_domain_attr
*attr
)
6889 enum s_alloc alloc_state
;
6890 struct sched_domain
*sd
;
6892 int i
, ret
= -ENOMEM
;
6894 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6895 if (alloc_state
!= sa_rootdomain
)
6898 /* Set up domains for cpus specified by the cpu_map. */
6899 for_each_cpu(i
, cpu_map
) {
6900 struct sched_domain_topology_level
*tl
;
6903 for_each_sd_topology(tl
) {
6904 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6905 if (tl
== sched_domain_topology
)
6906 *per_cpu_ptr(d
.sd
, i
) = sd
;
6907 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6908 sd
->flags
|= SD_OVERLAP
;
6909 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6914 /* Build the groups for the domains */
6915 for_each_cpu(i
, cpu_map
) {
6916 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6917 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6918 if (sd
->flags
& SD_OVERLAP
) {
6919 if (build_overlap_sched_groups(sd
, i
))
6922 if (build_sched_groups(sd
, i
))
6928 /* Calculate CPU capacity for physical packages and nodes */
6929 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6930 if (!cpumask_test_cpu(i
, cpu_map
))
6933 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6934 claim_allocations(i
, sd
);
6935 init_sched_groups_capacity(i
, sd
);
6939 /* Attach the domains */
6941 for_each_cpu(i
, cpu_map
) {
6942 sd
= *per_cpu_ptr(d
.sd
, i
);
6943 cpu_attach_domain(sd
, d
.rd
, i
);
6949 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6953 static cpumask_var_t
*doms_cur
; /* current sched domains */
6954 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6955 static struct sched_domain_attr
*dattr_cur
;
6956 /* attribues of custom domains in 'doms_cur' */
6959 * Special case: If a kmalloc of a doms_cur partition (array of
6960 * cpumask) fails, then fallback to a single sched domain,
6961 * as determined by the single cpumask fallback_doms.
6963 static cpumask_var_t fallback_doms
;
6966 * arch_update_cpu_topology lets virtualized architectures update the
6967 * cpu core maps. It is supposed to return 1 if the topology changed
6968 * or 0 if it stayed the same.
6970 int __weak
arch_update_cpu_topology(void)
6975 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6978 cpumask_var_t
*doms
;
6980 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6983 for (i
= 0; i
< ndoms
; i
++) {
6984 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6985 free_sched_domains(doms
, i
);
6992 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6995 for (i
= 0; i
< ndoms
; i
++)
6996 free_cpumask_var(doms
[i
]);
7001 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7002 * For now this just excludes isolated cpus, but could be used to
7003 * exclude other special cases in the future.
7005 static int init_sched_domains(const struct cpumask
*cpu_map
)
7009 arch_update_cpu_topology();
7011 doms_cur
= alloc_sched_domains(ndoms_cur
);
7013 doms_cur
= &fallback_doms
;
7014 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
7015 err
= build_sched_domains(doms_cur
[0], NULL
);
7016 register_sched_domain_sysctl();
7022 * Detach sched domains from a group of cpus specified in cpu_map
7023 * These cpus will now be attached to the NULL domain
7025 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7030 for_each_cpu(i
, cpu_map
)
7031 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7035 /* handle null as "default" */
7036 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7037 struct sched_domain_attr
*new, int idx_new
)
7039 struct sched_domain_attr tmp
;
7046 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7047 new ? (new + idx_new
) : &tmp
,
7048 sizeof(struct sched_domain_attr
));
7052 * Partition sched domains as specified by the 'ndoms_new'
7053 * cpumasks in the array doms_new[] of cpumasks. This compares
7054 * doms_new[] to the current sched domain partitioning, doms_cur[].
7055 * It destroys each deleted domain and builds each new domain.
7057 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7058 * The masks don't intersect (don't overlap.) We should setup one
7059 * sched domain for each mask. CPUs not in any of the cpumasks will
7060 * not be load balanced. If the same cpumask appears both in the
7061 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7064 * The passed in 'doms_new' should be allocated using
7065 * alloc_sched_domains. This routine takes ownership of it and will
7066 * free_sched_domains it when done with it. If the caller failed the
7067 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7068 * and partition_sched_domains() will fallback to the single partition
7069 * 'fallback_doms', it also forces the domains to be rebuilt.
7071 * If doms_new == NULL it will be replaced with cpu_online_mask.
7072 * ndoms_new == 0 is a special case for destroying existing domains,
7073 * and it will not create the default domain.
7075 * Call with hotplug lock held
7077 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
7078 struct sched_domain_attr
*dattr_new
)
7083 mutex_lock(&sched_domains_mutex
);
7085 /* always unregister in case we don't destroy any domains */
7086 unregister_sched_domain_sysctl();
7088 /* Let architecture update cpu core mappings. */
7089 new_topology
= arch_update_cpu_topology();
7091 n
= doms_new
? ndoms_new
: 0;
7093 /* Destroy deleted domains */
7094 for (i
= 0; i
< ndoms_cur
; i
++) {
7095 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7096 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
7097 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7100 /* no match - a current sched domain not in new doms_new[] */
7101 detach_destroy_domains(doms_cur
[i
]);
7107 if (doms_new
== NULL
) {
7109 doms_new
= &fallback_doms
;
7110 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
7111 WARN_ON_ONCE(dattr_new
);
7114 /* Build new domains */
7115 for (i
= 0; i
< ndoms_new
; i
++) {
7116 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7117 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
7118 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7121 /* no match - add a new doms_new */
7122 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
7127 /* Remember the new sched domains */
7128 if (doms_cur
!= &fallback_doms
)
7129 free_sched_domains(doms_cur
, ndoms_cur
);
7130 kfree(dattr_cur
); /* kfree(NULL) is safe */
7131 doms_cur
= doms_new
;
7132 dattr_cur
= dattr_new
;
7133 ndoms_cur
= ndoms_new
;
7135 register_sched_domain_sysctl();
7137 mutex_unlock(&sched_domains_mutex
);
7140 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
7143 * Update cpusets according to cpu_active mask. If cpusets are
7144 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7145 * around partition_sched_domains().
7147 * If we come here as part of a suspend/resume, don't touch cpusets because we
7148 * want to restore it back to its original state upon resume anyway.
7150 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
7154 case CPU_ONLINE_FROZEN
:
7155 case CPU_DOWN_FAILED_FROZEN
:
7158 * num_cpus_frozen tracks how many CPUs are involved in suspend
7159 * resume sequence. As long as this is not the last online
7160 * operation in the resume sequence, just build a single sched
7161 * domain, ignoring cpusets.
7164 if (likely(num_cpus_frozen
)) {
7165 partition_sched_domains(1, NULL
, NULL
);
7170 * This is the last CPU online operation. So fall through and
7171 * restore the original sched domains by considering the
7172 * cpuset configurations.
7176 cpuset_update_active_cpus(true);
7184 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7187 unsigned long flags
;
7188 long cpu
= (long)hcpu
;
7194 case CPU_DOWN_PREPARE
:
7195 rcu_read_lock_sched();
7196 dl_b
= dl_bw_of(cpu
);
7198 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7199 cpus
= dl_bw_cpus(cpu
);
7200 overflow
= __dl_overflow(dl_b
, cpus
, 0, 0);
7201 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7203 rcu_read_unlock_sched();
7206 return notifier_from_errno(-EBUSY
);
7207 cpuset_update_active_cpus(false);
7209 case CPU_DOWN_PREPARE_FROZEN
:
7211 partition_sched_domains(1, NULL
, NULL
);
7219 void __init
sched_init_smp(void)
7221 cpumask_var_t non_isolated_cpus
;
7223 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7224 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7226 /* nohz_full won't take effect without isolating the cpus. */
7227 tick_nohz_full_add_cpus_to(cpu_isolated_map
);
7232 * There's no userspace yet to cause hotplug operations; hence all the
7233 * cpu masks are stable and all blatant races in the below code cannot
7236 mutex_lock(&sched_domains_mutex
);
7237 init_sched_domains(cpu_active_mask
);
7238 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7239 if (cpumask_empty(non_isolated_cpus
))
7240 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7241 mutex_unlock(&sched_domains_mutex
);
7243 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
7244 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7245 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7249 /* Move init over to a non-isolated CPU */
7250 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7252 sched_init_granularity();
7253 free_cpumask_var(non_isolated_cpus
);
7255 init_sched_rt_class();
7256 init_sched_dl_class();
7259 void __init
sched_init_smp(void)
7261 sched_init_granularity();
7263 #endif /* CONFIG_SMP */
7265 int in_sched_functions(unsigned long addr
)
7267 return in_lock_functions(addr
) ||
7268 (addr
>= (unsigned long)__sched_text_start
7269 && addr
< (unsigned long)__sched_text_end
);
7272 #ifdef CONFIG_CGROUP_SCHED
7274 * Default task group.
7275 * Every task in system belongs to this group at bootup.
7277 struct task_group root_task_group
;
7278 LIST_HEAD(task_groups
);
7281 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
7283 void __init
sched_init(void)
7286 unsigned long alloc_size
= 0, ptr
;
7288 #ifdef CONFIG_FAIR_GROUP_SCHED
7289 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7291 #ifdef CONFIG_RT_GROUP_SCHED
7292 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7295 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
7297 #ifdef CONFIG_FAIR_GROUP_SCHED
7298 root_task_group
.se
= (struct sched_entity
**)ptr
;
7299 ptr
+= nr_cpu_ids
* sizeof(void **);
7301 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7302 ptr
+= nr_cpu_ids
* sizeof(void **);
7304 #endif /* CONFIG_FAIR_GROUP_SCHED */
7305 #ifdef CONFIG_RT_GROUP_SCHED
7306 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7307 ptr
+= nr_cpu_ids
* sizeof(void **);
7309 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7310 ptr
+= nr_cpu_ids
* sizeof(void **);
7312 #endif /* CONFIG_RT_GROUP_SCHED */
7314 #ifdef CONFIG_CPUMASK_OFFSTACK
7315 for_each_possible_cpu(i
) {
7316 per_cpu(load_balance_mask
, i
) = (cpumask_var_t
)kzalloc_node(
7317 cpumask_size(), GFP_KERNEL
, cpu_to_node(i
));
7319 #endif /* CONFIG_CPUMASK_OFFSTACK */
7321 init_rt_bandwidth(&def_rt_bandwidth
,
7322 global_rt_period(), global_rt_runtime());
7323 init_dl_bandwidth(&def_dl_bandwidth
,
7324 global_rt_period(), global_rt_runtime());
7327 init_defrootdomain();
7330 #ifdef CONFIG_RT_GROUP_SCHED
7331 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7332 global_rt_period(), global_rt_runtime());
7333 #endif /* CONFIG_RT_GROUP_SCHED */
7335 #ifdef CONFIG_CGROUP_SCHED
7336 list_add(&root_task_group
.list
, &task_groups
);
7337 INIT_LIST_HEAD(&root_task_group
.children
);
7338 INIT_LIST_HEAD(&root_task_group
.siblings
);
7339 autogroup_init(&init_task
);
7341 #endif /* CONFIG_CGROUP_SCHED */
7343 for_each_possible_cpu(i
) {
7347 raw_spin_lock_init(&rq
->lock
);
7349 rq
->calc_load_active
= 0;
7350 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
7351 init_cfs_rq(&rq
->cfs
);
7352 init_rt_rq(&rq
->rt
);
7353 init_dl_rq(&rq
->dl
);
7354 #ifdef CONFIG_FAIR_GROUP_SCHED
7355 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
7356 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7358 * How much cpu bandwidth does root_task_group get?
7360 * In case of task-groups formed thr' the cgroup filesystem, it
7361 * gets 100% of the cpu resources in the system. This overall
7362 * system cpu resource is divided among the tasks of
7363 * root_task_group and its child task-groups in a fair manner,
7364 * based on each entity's (task or task-group's) weight
7365 * (se->load.weight).
7367 * In other words, if root_task_group has 10 tasks of weight
7368 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7369 * then A0's share of the cpu resource is:
7371 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7373 * We achieve this by letting root_task_group's tasks sit
7374 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7376 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
7377 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
7378 #endif /* CONFIG_FAIR_GROUP_SCHED */
7380 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7381 #ifdef CONFIG_RT_GROUP_SCHED
7382 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
7385 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7386 rq
->cpu_load
[j
] = 0;
7388 rq
->last_load_update_tick
= jiffies
;
7393 rq
->cpu_capacity
= rq
->cpu_capacity_orig
= SCHED_CAPACITY_SCALE
;
7394 rq
->balance_callback
= NULL
;
7395 rq
->active_balance
= 0;
7396 rq
->next_balance
= jiffies
;
7401 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7402 rq
->max_idle_balance_cost
= sysctl_sched_migration_cost
;
7404 INIT_LIST_HEAD(&rq
->cfs_tasks
);
7406 rq_attach_root(rq
, &def_root_domain
);
7407 #ifdef CONFIG_NO_HZ_COMMON
7410 #ifdef CONFIG_NO_HZ_FULL
7411 rq
->last_sched_tick
= 0;
7415 atomic_set(&rq
->nr_iowait
, 0);
7418 set_load_weight(&init_task
);
7420 #ifdef CONFIG_PREEMPT_NOTIFIERS
7421 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7425 * The boot idle thread does lazy MMU switching as well:
7427 atomic_inc(&init_mm
.mm_count
);
7428 enter_lazy_tlb(&init_mm
, current
);
7431 * During early bootup we pretend to be a normal task:
7433 current
->sched_class
= &fair_sched_class
;
7436 * Make us the idle thread. Technically, schedule() should not be
7437 * called from this thread, however somewhere below it might be,
7438 * but because we are the idle thread, we just pick up running again
7439 * when this runqueue becomes "idle".
7441 init_idle(current
, smp_processor_id());
7443 calc_load_update
= jiffies
+ LOAD_FREQ
;
7446 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
7447 /* May be allocated at isolcpus cmdline parse time */
7448 if (cpu_isolated_map
== NULL
)
7449 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7450 idle_thread_set_boot_cpu();
7451 set_cpu_rq_start_time();
7453 init_sched_fair_class();
7455 scheduler_running
= 1;
7458 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7459 static inline int preempt_count_equals(int preempt_offset
)
7461 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7463 return (nested
== preempt_offset
);
7466 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7469 * Blocking primitives will set (and therefore destroy) current->state,
7470 * since we will exit with TASK_RUNNING make sure we enter with it,
7471 * otherwise we will destroy state.
7473 WARN_ONCE(current
->state
!= TASK_RUNNING
&& current
->task_state_change
,
7474 "do not call blocking ops when !TASK_RUNNING; "
7475 "state=%lx set at [<%p>] %pS\n",
7477 (void *)current
->task_state_change
,
7478 (void *)current
->task_state_change
);
7480 ___might_sleep(file
, line
, preempt_offset
);
7482 EXPORT_SYMBOL(__might_sleep
);
7484 void ___might_sleep(const char *file
, int line
, int preempt_offset
)
7486 static unsigned long prev_jiffy
; /* ratelimiting */
7488 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7489 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled() &&
7490 !is_idle_task(current
)) ||
7491 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7493 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7495 prev_jiffy
= jiffies
;
7498 "BUG: sleeping function called from invalid context at %s:%d\n",
7501 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7502 in_atomic(), irqs_disabled(),
7503 current
->pid
, current
->comm
);
7505 if (task_stack_end_corrupted(current
))
7506 printk(KERN_EMERG
"Thread overran stack, or stack corrupted\n");
7508 debug_show_held_locks(current
);
7509 if (irqs_disabled())
7510 print_irqtrace_events(current
);
7511 #ifdef CONFIG_DEBUG_PREEMPT
7512 if (!preempt_count_equals(preempt_offset
)) {
7513 pr_err("Preemption disabled at:");
7514 print_ip_sym(current
->preempt_disable_ip
);
7520 EXPORT_SYMBOL(___might_sleep
);
7523 #ifdef CONFIG_MAGIC_SYSRQ
7524 void normalize_rt_tasks(void)
7526 struct task_struct
*g
, *p
;
7527 struct sched_attr attr
= {
7528 .sched_policy
= SCHED_NORMAL
,
7531 read_lock(&tasklist_lock
);
7532 for_each_process_thread(g
, p
) {
7534 * Only normalize user tasks:
7536 if (p
->flags
& PF_KTHREAD
)
7539 p
->se
.exec_start
= 0;
7540 #ifdef CONFIG_SCHEDSTATS
7541 p
->se
.statistics
.wait_start
= 0;
7542 p
->se
.statistics
.sleep_start
= 0;
7543 p
->se
.statistics
.block_start
= 0;
7546 if (!dl_task(p
) && !rt_task(p
)) {
7548 * Renice negative nice level userspace
7551 if (task_nice(p
) < 0)
7552 set_user_nice(p
, 0);
7556 __sched_setscheduler(p
, &attr
, false, false);
7558 read_unlock(&tasklist_lock
);
7561 #endif /* CONFIG_MAGIC_SYSRQ */
7563 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7565 * These functions are only useful for the IA64 MCA handling, or kdb.
7567 * They can only be called when the whole system has been
7568 * stopped - every CPU needs to be quiescent, and no scheduling
7569 * activity can take place. Using them for anything else would
7570 * be a serious bug, and as a result, they aren't even visible
7571 * under any other configuration.
7575 * curr_task - return the current task for a given cpu.
7576 * @cpu: the processor in question.
7578 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7580 * Return: The current task for @cpu.
7582 struct task_struct
*curr_task(int cpu
)
7584 return cpu_curr(cpu
);
7587 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7591 * set_curr_task - set the current task for a given cpu.
7592 * @cpu: the processor in question.
7593 * @p: the task pointer to set.
7595 * Description: This function must only be used when non-maskable interrupts
7596 * are serviced on a separate stack. It allows the architecture to switch the
7597 * notion of the current task on a cpu in a non-blocking manner. This function
7598 * must be called with all CPU's synchronized, and interrupts disabled, the
7599 * and caller must save the original value of the current task (see
7600 * curr_task() above) and restore that value before reenabling interrupts and
7601 * re-starting the system.
7603 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7605 void set_curr_task(int cpu
, struct task_struct
*p
)
7612 #ifdef CONFIG_CGROUP_SCHED
7613 /* task_group_lock serializes the addition/removal of task groups */
7614 static DEFINE_SPINLOCK(task_group_lock
);
7616 static void free_sched_group(struct task_group
*tg
)
7618 free_fair_sched_group(tg
);
7619 free_rt_sched_group(tg
);
7624 /* allocate runqueue etc for a new task group */
7625 struct task_group
*sched_create_group(struct task_group
*parent
)
7627 struct task_group
*tg
;
7629 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7631 return ERR_PTR(-ENOMEM
);
7633 if (!alloc_fair_sched_group(tg
, parent
))
7636 if (!alloc_rt_sched_group(tg
, parent
))
7642 free_sched_group(tg
);
7643 return ERR_PTR(-ENOMEM
);
7646 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
7648 unsigned long flags
;
7650 spin_lock_irqsave(&task_group_lock
, flags
);
7651 list_add_rcu(&tg
->list
, &task_groups
);
7653 WARN_ON(!parent
); /* root should already exist */
7655 tg
->parent
= parent
;
7656 INIT_LIST_HEAD(&tg
->children
);
7657 list_add_rcu(&tg
->siblings
, &parent
->children
);
7658 spin_unlock_irqrestore(&task_group_lock
, flags
);
7661 /* rcu callback to free various structures associated with a task group */
7662 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7664 /* now it should be safe to free those cfs_rqs */
7665 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7668 /* Destroy runqueue etc associated with a task group */
7669 void sched_destroy_group(struct task_group
*tg
)
7671 /* wait for possible concurrent references to cfs_rqs complete */
7672 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7675 void sched_offline_group(struct task_group
*tg
)
7677 unsigned long flags
;
7680 /* end participation in shares distribution */
7681 for_each_possible_cpu(i
)
7682 unregister_fair_sched_group(tg
, i
);
7684 spin_lock_irqsave(&task_group_lock
, flags
);
7685 list_del_rcu(&tg
->list
);
7686 list_del_rcu(&tg
->siblings
);
7687 spin_unlock_irqrestore(&task_group_lock
, flags
);
7690 /* change task's runqueue when it moves between groups.
7691 * The caller of this function should have put the task in its new group
7692 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7693 * reflect its new group.
7695 void sched_move_task(struct task_struct
*tsk
)
7697 struct task_group
*tg
;
7698 int queued
, running
;
7699 unsigned long flags
;
7702 rq
= task_rq_lock(tsk
, &flags
);
7704 running
= task_current(rq
, tsk
);
7705 queued
= task_on_rq_queued(tsk
);
7708 dequeue_task(rq
, tsk
, 0);
7709 if (unlikely(running
))
7710 put_prev_task(rq
, tsk
);
7713 * All callers are synchronized by task_rq_lock(); we do not use RCU
7714 * which is pointless here. Thus, we pass "true" to task_css_check()
7715 * to prevent lockdep warnings.
7717 tg
= container_of(task_css_check(tsk
, cpu_cgrp_id
, true),
7718 struct task_group
, css
);
7719 tg
= autogroup_task_group(tsk
, tg
);
7720 tsk
->sched_task_group
= tg
;
7722 #ifdef CONFIG_FAIR_GROUP_SCHED
7723 if (tsk
->sched_class
->task_move_group
)
7724 tsk
->sched_class
->task_move_group(tsk
);
7727 set_task_rq(tsk
, task_cpu(tsk
));
7729 if (unlikely(running
))
7730 tsk
->sched_class
->set_curr_task(rq
);
7732 enqueue_task(rq
, tsk
, 0);
7734 task_rq_unlock(rq
, tsk
, &flags
);
7736 #endif /* CONFIG_CGROUP_SCHED */
7738 #ifdef CONFIG_RT_GROUP_SCHED
7740 * Ensure that the real time constraints are schedulable.
7742 static DEFINE_MUTEX(rt_constraints_mutex
);
7744 /* Must be called with tasklist_lock held */
7745 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7747 struct task_struct
*g
, *p
;
7750 * Autogroups do not have RT tasks; see autogroup_create().
7752 if (task_group_is_autogroup(tg
))
7755 for_each_process_thread(g
, p
) {
7756 if (rt_task(p
) && task_group(p
) == tg
)
7763 struct rt_schedulable_data
{
7764 struct task_group
*tg
;
7769 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7771 struct rt_schedulable_data
*d
= data
;
7772 struct task_group
*child
;
7773 unsigned long total
, sum
= 0;
7774 u64 period
, runtime
;
7776 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7777 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7780 period
= d
->rt_period
;
7781 runtime
= d
->rt_runtime
;
7785 * Cannot have more runtime than the period.
7787 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7791 * Ensure we don't starve existing RT tasks.
7793 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7796 total
= to_ratio(period
, runtime
);
7799 * Nobody can have more than the global setting allows.
7801 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7805 * The sum of our children's runtime should not exceed our own.
7807 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7808 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7809 runtime
= child
->rt_bandwidth
.rt_runtime
;
7811 if (child
== d
->tg
) {
7812 period
= d
->rt_period
;
7813 runtime
= d
->rt_runtime
;
7816 sum
+= to_ratio(period
, runtime
);
7825 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7829 struct rt_schedulable_data data
= {
7831 .rt_period
= period
,
7832 .rt_runtime
= runtime
,
7836 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7842 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7843 u64 rt_period
, u64 rt_runtime
)
7848 * Disallowing the root group RT runtime is BAD, it would disallow the
7849 * kernel creating (and or operating) RT threads.
7851 if (tg
== &root_task_group
&& rt_runtime
== 0)
7854 /* No period doesn't make any sense. */
7858 mutex_lock(&rt_constraints_mutex
);
7859 read_lock(&tasklist_lock
);
7860 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7864 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7865 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7866 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7868 for_each_possible_cpu(i
) {
7869 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7871 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7872 rt_rq
->rt_runtime
= rt_runtime
;
7873 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7875 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7877 read_unlock(&tasklist_lock
);
7878 mutex_unlock(&rt_constraints_mutex
);
7883 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7885 u64 rt_runtime
, rt_period
;
7887 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7888 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7889 if (rt_runtime_us
< 0)
7890 rt_runtime
= RUNTIME_INF
;
7892 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7895 static long sched_group_rt_runtime(struct task_group
*tg
)
7899 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7902 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7903 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7904 return rt_runtime_us
;
7907 static int sched_group_set_rt_period(struct task_group
*tg
, u64 rt_period_us
)
7909 u64 rt_runtime
, rt_period
;
7911 rt_period
= rt_period_us
* NSEC_PER_USEC
;
7912 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7914 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7917 static long sched_group_rt_period(struct task_group
*tg
)
7921 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7922 do_div(rt_period_us
, NSEC_PER_USEC
);
7923 return rt_period_us
;
7925 #endif /* CONFIG_RT_GROUP_SCHED */
7927 #ifdef CONFIG_RT_GROUP_SCHED
7928 static int sched_rt_global_constraints(void)
7932 mutex_lock(&rt_constraints_mutex
);
7933 read_lock(&tasklist_lock
);
7934 ret
= __rt_schedulable(NULL
, 0, 0);
7935 read_unlock(&tasklist_lock
);
7936 mutex_unlock(&rt_constraints_mutex
);
7941 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7943 /* Don't accept realtime tasks when there is no way for them to run */
7944 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7950 #else /* !CONFIG_RT_GROUP_SCHED */
7951 static int sched_rt_global_constraints(void)
7953 unsigned long flags
;
7956 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7957 for_each_possible_cpu(i
) {
7958 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7960 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7961 rt_rq
->rt_runtime
= global_rt_runtime();
7962 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7964 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7968 #endif /* CONFIG_RT_GROUP_SCHED */
7970 static int sched_dl_global_validate(void)
7972 u64 runtime
= global_rt_runtime();
7973 u64 period
= global_rt_period();
7974 u64 new_bw
= to_ratio(period
, runtime
);
7977 unsigned long flags
;
7980 * Here we want to check the bandwidth not being set to some
7981 * value smaller than the currently allocated bandwidth in
7982 * any of the root_domains.
7984 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7985 * cycling on root_domains... Discussion on different/better
7986 * solutions is welcome!
7988 for_each_possible_cpu(cpu
) {
7989 rcu_read_lock_sched();
7990 dl_b
= dl_bw_of(cpu
);
7992 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7993 if (new_bw
< dl_b
->total_bw
)
7995 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7997 rcu_read_unlock_sched();
8006 static void sched_dl_do_global(void)
8011 unsigned long flags
;
8013 def_dl_bandwidth
.dl_period
= global_rt_period();
8014 def_dl_bandwidth
.dl_runtime
= global_rt_runtime();
8016 if (global_rt_runtime() != RUNTIME_INF
)
8017 new_bw
= to_ratio(global_rt_period(), global_rt_runtime());
8020 * FIXME: As above...
8022 for_each_possible_cpu(cpu
) {
8023 rcu_read_lock_sched();
8024 dl_b
= dl_bw_of(cpu
);
8026 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
8028 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
8030 rcu_read_unlock_sched();
8034 static int sched_rt_global_validate(void)
8036 if (sysctl_sched_rt_period
<= 0)
8039 if ((sysctl_sched_rt_runtime
!= RUNTIME_INF
) &&
8040 (sysctl_sched_rt_runtime
> sysctl_sched_rt_period
))
8046 static void sched_rt_do_global(void)
8048 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8049 def_rt_bandwidth
.rt_period
= ns_to_ktime(global_rt_period());
8052 int sched_rt_handler(struct ctl_table
*table
, int write
,
8053 void __user
*buffer
, size_t *lenp
,
8056 int old_period
, old_runtime
;
8057 static DEFINE_MUTEX(mutex
);
8061 old_period
= sysctl_sched_rt_period
;
8062 old_runtime
= sysctl_sched_rt_runtime
;
8064 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
8066 if (!ret
&& write
) {
8067 ret
= sched_rt_global_validate();
8071 ret
= sched_dl_global_validate();
8075 ret
= sched_rt_global_constraints();
8079 sched_rt_do_global();
8080 sched_dl_do_global();
8084 sysctl_sched_rt_period
= old_period
;
8085 sysctl_sched_rt_runtime
= old_runtime
;
8087 mutex_unlock(&mutex
);
8092 int sched_rr_handler(struct ctl_table
*table
, int write
,
8093 void __user
*buffer
, size_t *lenp
,
8097 static DEFINE_MUTEX(mutex
);
8100 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
8101 /* make sure that internally we keep jiffies */
8102 /* also, writing zero resets timeslice to default */
8103 if (!ret
&& write
) {
8104 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
8105 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
8107 mutex_unlock(&mutex
);
8111 #ifdef CONFIG_CGROUP_SCHED
8113 static inline struct task_group
*css_tg(struct cgroup_subsys_state
*css
)
8115 return css
? container_of(css
, struct task_group
, css
) : NULL
;
8118 static struct cgroup_subsys_state
*
8119 cpu_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
8121 struct task_group
*parent
= css_tg(parent_css
);
8122 struct task_group
*tg
;
8125 /* This is early initialization for the top cgroup */
8126 return &root_task_group
.css
;
8129 tg
= sched_create_group(parent
);
8131 return ERR_PTR(-ENOMEM
);
8136 static int cpu_cgroup_css_online(struct cgroup_subsys_state
*css
)
8138 struct task_group
*tg
= css_tg(css
);
8139 struct task_group
*parent
= css_tg(css
->parent
);
8142 sched_online_group(tg
, parent
);
8146 static void cpu_cgroup_css_free(struct cgroup_subsys_state
*css
)
8148 struct task_group
*tg
= css_tg(css
);
8150 sched_destroy_group(tg
);
8153 static void cpu_cgroup_css_offline(struct cgroup_subsys_state
*css
)
8155 struct task_group
*tg
= css_tg(css
);
8157 sched_offline_group(tg
);
8160 static void cpu_cgroup_fork(struct task_struct
*task
, void *private)
8162 sched_move_task(task
);
8165 static int cpu_cgroup_can_attach(struct cgroup_subsys_state
*css
,
8166 struct cgroup_taskset
*tset
)
8168 struct task_struct
*task
;
8170 cgroup_taskset_for_each(task
, tset
) {
8171 #ifdef CONFIG_RT_GROUP_SCHED
8172 if (!sched_rt_can_attach(css_tg(css
), task
))
8175 /* We don't support RT-tasks being in separate groups */
8176 if (task
->sched_class
!= &fair_sched_class
)
8183 static void cpu_cgroup_attach(struct cgroup_subsys_state
*css
,
8184 struct cgroup_taskset
*tset
)
8186 struct task_struct
*task
;
8188 cgroup_taskset_for_each(task
, tset
)
8189 sched_move_task(task
);
8192 static void cpu_cgroup_exit(struct cgroup_subsys_state
*css
,
8193 struct cgroup_subsys_state
*old_css
,
8194 struct task_struct
*task
)
8197 * cgroup_exit() is called in the copy_process() failure path.
8198 * Ignore this case since the task hasn't ran yet, this avoids
8199 * trying to poke a half freed task state from generic code.
8201 if (!(task
->flags
& PF_EXITING
))
8204 sched_move_task(task
);
8207 #ifdef CONFIG_FAIR_GROUP_SCHED
8208 static int cpu_shares_write_u64(struct cgroup_subsys_state
*css
,
8209 struct cftype
*cftype
, u64 shareval
)
8211 return sched_group_set_shares(css_tg(css
), scale_load(shareval
));
8214 static u64
cpu_shares_read_u64(struct cgroup_subsys_state
*css
,
8217 struct task_group
*tg
= css_tg(css
);
8219 return (u64
) scale_load_down(tg
->shares
);
8222 #ifdef CONFIG_CFS_BANDWIDTH
8223 static DEFINE_MUTEX(cfs_constraints_mutex
);
8225 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
8226 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
8228 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
8230 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
8232 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
8233 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8235 if (tg
== &root_task_group
)
8239 * Ensure we have at some amount of bandwidth every period. This is
8240 * to prevent reaching a state of large arrears when throttled via
8241 * entity_tick() resulting in prolonged exit starvation.
8243 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
8247 * Likewise, bound things on the otherside by preventing insane quota
8248 * periods. This also allows us to normalize in computing quota
8251 if (period
> max_cfs_quota_period
)
8255 * Prevent race between setting of cfs_rq->runtime_enabled and
8256 * unthrottle_offline_cfs_rqs().
8259 mutex_lock(&cfs_constraints_mutex
);
8260 ret
= __cfs_schedulable(tg
, period
, quota
);
8264 runtime_enabled
= quota
!= RUNTIME_INF
;
8265 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
8267 * If we need to toggle cfs_bandwidth_used, off->on must occur
8268 * before making related changes, and on->off must occur afterwards
8270 if (runtime_enabled
&& !runtime_was_enabled
)
8271 cfs_bandwidth_usage_inc();
8272 raw_spin_lock_irq(&cfs_b
->lock
);
8273 cfs_b
->period
= ns_to_ktime(period
);
8274 cfs_b
->quota
= quota
;
8276 __refill_cfs_bandwidth_runtime(cfs_b
);
8277 /* restart the period timer (if active) to handle new period expiry */
8278 if (runtime_enabled
)
8279 start_cfs_bandwidth(cfs_b
);
8280 raw_spin_unlock_irq(&cfs_b
->lock
);
8282 for_each_online_cpu(i
) {
8283 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
8284 struct rq
*rq
= cfs_rq
->rq
;
8286 raw_spin_lock_irq(&rq
->lock
);
8287 cfs_rq
->runtime_enabled
= runtime_enabled
;
8288 cfs_rq
->runtime_remaining
= 0;
8290 if (cfs_rq
->throttled
)
8291 unthrottle_cfs_rq(cfs_rq
);
8292 raw_spin_unlock_irq(&rq
->lock
);
8294 if (runtime_was_enabled
&& !runtime_enabled
)
8295 cfs_bandwidth_usage_dec();
8297 mutex_unlock(&cfs_constraints_mutex
);
8303 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
8307 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
8308 if (cfs_quota_us
< 0)
8309 quota
= RUNTIME_INF
;
8311 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
8313 return tg_set_cfs_bandwidth(tg
, period
, quota
);
8316 long tg_get_cfs_quota(struct task_group
*tg
)
8320 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
8323 quota_us
= tg
->cfs_bandwidth
.quota
;
8324 do_div(quota_us
, NSEC_PER_USEC
);
8329 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
8333 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
8334 quota
= tg
->cfs_bandwidth
.quota
;
8336 return tg_set_cfs_bandwidth(tg
, period
, quota
);
8339 long tg_get_cfs_period(struct task_group
*tg
)
8343 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
8344 do_div(cfs_period_us
, NSEC_PER_USEC
);
8346 return cfs_period_us
;
8349 static s64
cpu_cfs_quota_read_s64(struct cgroup_subsys_state
*css
,
8352 return tg_get_cfs_quota(css_tg(css
));
8355 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state
*css
,
8356 struct cftype
*cftype
, s64 cfs_quota_us
)
8358 return tg_set_cfs_quota(css_tg(css
), cfs_quota_us
);
8361 static u64
cpu_cfs_period_read_u64(struct cgroup_subsys_state
*css
,
8364 return tg_get_cfs_period(css_tg(css
));
8367 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state
*css
,
8368 struct cftype
*cftype
, u64 cfs_period_us
)
8370 return tg_set_cfs_period(css_tg(css
), cfs_period_us
);
8373 struct cfs_schedulable_data
{
8374 struct task_group
*tg
;
8379 * normalize group quota/period to be quota/max_period
8380 * note: units are usecs
8382 static u64
normalize_cfs_quota(struct task_group
*tg
,
8383 struct cfs_schedulable_data
*d
)
8391 period
= tg_get_cfs_period(tg
);
8392 quota
= tg_get_cfs_quota(tg
);
8395 /* note: these should typically be equivalent */
8396 if (quota
== RUNTIME_INF
|| quota
== -1)
8399 return to_ratio(period
, quota
);
8402 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
8404 struct cfs_schedulable_data
*d
= data
;
8405 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8406 s64 quota
= 0, parent_quota
= -1;
8409 quota
= RUNTIME_INF
;
8411 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
8413 quota
= normalize_cfs_quota(tg
, d
);
8414 parent_quota
= parent_b
->hierarchical_quota
;
8417 * ensure max(child_quota) <= parent_quota, inherit when no
8420 if (quota
== RUNTIME_INF
)
8421 quota
= parent_quota
;
8422 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
8425 cfs_b
->hierarchical_quota
= quota
;
8430 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
8433 struct cfs_schedulable_data data
= {
8439 if (quota
!= RUNTIME_INF
) {
8440 do_div(data
.period
, NSEC_PER_USEC
);
8441 do_div(data
.quota
, NSEC_PER_USEC
);
8445 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
8451 static int cpu_stats_show(struct seq_file
*sf
, void *v
)
8453 struct task_group
*tg
= css_tg(seq_css(sf
));
8454 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8456 seq_printf(sf
, "nr_periods %d\n", cfs_b
->nr_periods
);
8457 seq_printf(sf
, "nr_throttled %d\n", cfs_b
->nr_throttled
);
8458 seq_printf(sf
, "throttled_time %llu\n", cfs_b
->throttled_time
);
8462 #endif /* CONFIG_CFS_BANDWIDTH */
8463 #endif /* CONFIG_FAIR_GROUP_SCHED */
8465 #ifdef CONFIG_RT_GROUP_SCHED
8466 static int cpu_rt_runtime_write(struct cgroup_subsys_state
*css
,
8467 struct cftype
*cft
, s64 val
)
8469 return sched_group_set_rt_runtime(css_tg(css
), val
);
8472 static s64
cpu_rt_runtime_read(struct cgroup_subsys_state
*css
,
8475 return sched_group_rt_runtime(css_tg(css
));
8478 static int cpu_rt_period_write_uint(struct cgroup_subsys_state
*css
,
8479 struct cftype
*cftype
, u64 rt_period_us
)
8481 return sched_group_set_rt_period(css_tg(css
), rt_period_us
);
8484 static u64
cpu_rt_period_read_uint(struct cgroup_subsys_state
*css
,
8487 return sched_group_rt_period(css_tg(css
));
8489 #endif /* CONFIG_RT_GROUP_SCHED */
8491 static struct cftype cpu_files
[] = {
8492 #ifdef CONFIG_FAIR_GROUP_SCHED
8495 .read_u64
= cpu_shares_read_u64
,
8496 .write_u64
= cpu_shares_write_u64
,
8499 #ifdef CONFIG_CFS_BANDWIDTH
8501 .name
= "cfs_quota_us",
8502 .read_s64
= cpu_cfs_quota_read_s64
,
8503 .write_s64
= cpu_cfs_quota_write_s64
,
8506 .name
= "cfs_period_us",
8507 .read_u64
= cpu_cfs_period_read_u64
,
8508 .write_u64
= cpu_cfs_period_write_u64
,
8512 .seq_show
= cpu_stats_show
,
8515 #ifdef CONFIG_RT_GROUP_SCHED
8517 .name
= "rt_runtime_us",
8518 .read_s64
= cpu_rt_runtime_read
,
8519 .write_s64
= cpu_rt_runtime_write
,
8522 .name
= "rt_period_us",
8523 .read_u64
= cpu_rt_period_read_uint
,
8524 .write_u64
= cpu_rt_period_write_uint
,
8530 struct cgroup_subsys cpu_cgrp_subsys
= {
8531 .css_alloc
= cpu_cgroup_css_alloc
,
8532 .css_free
= cpu_cgroup_css_free
,
8533 .css_online
= cpu_cgroup_css_online
,
8534 .css_offline
= cpu_cgroup_css_offline
,
8535 .fork
= cpu_cgroup_fork
,
8536 .can_attach
= cpu_cgroup_can_attach
,
8537 .attach
= cpu_cgroup_attach
,
8538 .exit
= cpu_cgroup_exit
,
8539 .legacy_cftypes
= cpu_files
,
8543 #endif /* CONFIG_CGROUP_SCHED */
8545 void dump_cpu_task(int cpu
)
8547 pr_info("Task dump for CPU %d:\n", cpu
);
8548 sched_show_task(cpu_curr(cpu
));