4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <asm/mmu_context.h>
36 #include <linux/interrupt.h>
37 #include <linux/capability.h>
38 #include <linux/completion.h>
39 #include <linux/kernel_stat.h>
40 #include <linux/debug_locks.h>
41 #include <linux/perf_event.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/proc_fs.h>
58 #include <linux/seq_file.h>
59 #include <linux/sysctl.h>
60 #include <linux/syscalls.h>
61 #include <linux/times.h>
62 #include <linux/tsacct_kern.h>
63 #include <linux/kprobes.h>
64 #include <linux/delayacct.h>
65 #include <linux/unistd.h>
66 #include <linux/pagemap.h>
67 #include <linux/hrtimer.h>
68 #include <linux/tick.h>
69 #include <linux/debugfs.h>
70 #include <linux/ctype.h>
71 #include <linux/ftrace.h>
72 #include <linux/slab.h>
73 #include <linux/init_task.h>
74 #include <linux/binfmts.h>
75 #include <linux/context_tracking.h>
76 #include <linux/compiler.h>
78 #include <asm/switch_to.h>
80 #include <asm/irq_regs.h>
81 #include <asm/mutex.h>
82 #ifdef CONFIG_PARAVIRT
83 #include <asm/paravirt.h>
87 #include "../workqueue_internal.h"
88 #include "../smpboot.h"
90 #define CREATE_TRACE_POINTS
91 #include <trace/events/sched.h>
93 void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
96 ktime_t soft
, hard
, now
;
99 if (hrtimer_active(period_timer
))
102 now
= hrtimer_cb_get_time(period_timer
);
103 hrtimer_forward(period_timer
, now
, period
);
105 soft
= hrtimer_get_softexpires(period_timer
);
106 hard
= hrtimer_get_expires(period_timer
);
107 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
108 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
109 HRTIMER_MODE_ABS_PINNED
, 0);
113 DEFINE_MUTEX(sched_domains_mutex
);
114 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
116 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
118 void update_rq_clock(struct rq
*rq
)
122 if (rq
->skip_clock_update
> 0)
125 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
129 update_rq_clock_task(rq
, delta
);
133 * Debugging: various feature bits
136 #define SCHED_FEAT(name, enabled) \
137 (1UL << __SCHED_FEAT_##name) * enabled |
139 const_debug
unsigned int sysctl_sched_features
=
140 #include "features.h"
145 #ifdef CONFIG_SCHED_DEBUG
146 #define SCHED_FEAT(name, enabled) \
149 static const char * const sched_feat_names
[] = {
150 #include "features.h"
155 static int sched_feat_show(struct seq_file
*m
, void *v
)
159 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
160 if (!(sysctl_sched_features
& (1UL << i
)))
162 seq_printf(m
, "%s ", sched_feat_names
[i
]);
169 #ifdef HAVE_JUMP_LABEL
171 #define jump_label_key__true STATIC_KEY_INIT_TRUE
172 #define jump_label_key__false STATIC_KEY_INIT_FALSE
174 #define SCHED_FEAT(name, enabled) \
175 jump_label_key__##enabled ,
177 struct static_key sched_feat_keys
[__SCHED_FEAT_NR
] = {
178 #include "features.h"
183 static void sched_feat_disable(int i
)
185 if (static_key_enabled(&sched_feat_keys
[i
]))
186 static_key_slow_dec(&sched_feat_keys
[i
]);
189 static void sched_feat_enable(int i
)
191 if (!static_key_enabled(&sched_feat_keys
[i
]))
192 static_key_slow_inc(&sched_feat_keys
[i
]);
195 static void sched_feat_disable(int i
) { };
196 static void sched_feat_enable(int i
) { };
197 #endif /* HAVE_JUMP_LABEL */
199 static int sched_feat_set(char *cmp
)
204 if (strncmp(cmp
, "NO_", 3) == 0) {
209 for (i
= 0; i
< __SCHED_FEAT_NR
; i
++) {
210 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
212 sysctl_sched_features
&= ~(1UL << i
);
213 sched_feat_disable(i
);
215 sysctl_sched_features
|= (1UL << i
);
216 sched_feat_enable(i
);
226 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
227 size_t cnt
, loff_t
*ppos
)
237 if (copy_from_user(&buf
, ubuf
, cnt
))
243 /* Ensure the static_key remains in a consistent state */
244 inode
= file_inode(filp
);
245 mutex_lock(&inode
->i_mutex
);
246 i
= sched_feat_set(cmp
);
247 mutex_unlock(&inode
->i_mutex
);
248 if (i
== __SCHED_FEAT_NR
)
256 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
258 return single_open(filp
, sched_feat_show
, NULL
);
261 static const struct file_operations sched_feat_fops
= {
262 .open
= sched_feat_open
,
263 .write
= sched_feat_write
,
266 .release
= single_release
,
269 static __init
int sched_init_debug(void)
271 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
276 late_initcall(sched_init_debug
);
277 #endif /* CONFIG_SCHED_DEBUG */
280 * Number of tasks to iterate in a single balance run.
281 * Limited because this is done with IRQs disabled.
283 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
286 * period over which we average the RT time consumption, measured
291 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
294 * period over which we measure -rt task cpu usage in us.
297 unsigned int sysctl_sched_rt_period
= 1000000;
299 __read_mostly
int scheduler_running
;
302 * part of the period that we allow rt tasks to run in us.
305 int sysctl_sched_rt_runtime
= 950000;
308 * __task_rq_lock - lock the rq @p resides on.
310 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
315 lockdep_assert_held(&p
->pi_lock
);
319 raw_spin_lock(&rq
->lock
);
320 if (likely(rq
== task_rq(p
) && !task_on_rq_migrating(p
)))
322 raw_spin_unlock(&rq
->lock
);
324 while (unlikely(task_on_rq_migrating(p
)))
330 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
332 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
333 __acquires(p
->pi_lock
)
339 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
341 raw_spin_lock(&rq
->lock
);
342 if (likely(rq
== task_rq(p
) && !task_on_rq_migrating(p
)))
344 raw_spin_unlock(&rq
->lock
);
345 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
347 while (unlikely(task_on_rq_migrating(p
)))
352 static void __task_rq_unlock(struct rq
*rq
)
355 raw_spin_unlock(&rq
->lock
);
359 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
361 __releases(p
->pi_lock
)
363 raw_spin_unlock(&rq
->lock
);
364 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
368 * this_rq_lock - lock this runqueue and disable interrupts.
370 static struct rq
*this_rq_lock(void)
377 raw_spin_lock(&rq
->lock
);
382 #ifdef CONFIG_SCHED_HRTICK
384 * Use HR-timers to deliver accurate preemption points.
387 static void hrtick_clear(struct rq
*rq
)
389 if (hrtimer_active(&rq
->hrtick_timer
))
390 hrtimer_cancel(&rq
->hrtick_timer
);
394 * High-resolution timer tick.
395 * Runs from hardirq context with interrupts disabled.
397 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
399 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
401 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
403 raw_spin_lock(&rq
->lock
);
405 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
406 raw_spin_unlock(&rq
->lock
);
408 return HRTIMER_NORESTART
;
413 static int __hrtick_restart(struct rq
*rq
)
415 struct hrtimer
*timer
= &rq
->hrtick_timer
;
416 ktime_t time
= hrtimer_get_softexpires(timer
);
418 return __hrtimer_start_range_ns(timer
, time
, 0, HRTIMER_MODE_ABS_PINNED
, 0);
422 * called from hardirq (IPI) context
424 static void __hrtick_start(void *arg
)
428 raw_spin_lock(&rq
->lock
);
429 __hrtick_restart(rq
);
430 rq
->hrtick_csd_pending
= 0;
431 raw_spin_unlock(&rq
->lock
);
435 * Called to set the hrtick timer state.
437 * called with rq->lock held and irqs disabled
439 void hrtick_start(struct rq
*rq
, u64 delay
)
441 struct hrtimer
*timer
= &rq
->hrtick_timer
;
446 * Don't schedule slices shorter than 10000ns, that just
447 * doesn't make sense and can cause timer DoS.
449 delta
= max_t(s64
, delay
, 10000LL);
450 time
= ktime_add_ns(timer
->base
->get_time(), delta
);
452 hrtimer_set_expires(timer
, time
);
454 if (rq
== this_rq()) {
455 __hrtick_restart(rq
);
456 } else if (!rq
->hrtick_csd_pending
) {
457 smp_call_function_single_async(cpu_of(rq
), &rq
->hrtick_csd
);
458 rq
->hrtick_csd_pending
= 1;
463 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
465 int cpu
= (int)(long)hcpu
;
468 case CPU_UP_CANCELED
:
469 case CPU_UP_CANCELED_FROZEN
:
470 case CPU_DOWN_PREPARE
:
471 case CPU_DOWN_PREPARE_FROZEN
:
473 case CPU_DEAD_FROZEN
:
474 hrtick_clear(cpu_rq(cpu
));
481 static __init
void init_hrtick(void)
483 hotcpu_notifier(hotplug_hrtick
, 0);
487 * Called to set the hrtick timer state.
489 * called with rq->lock held and irqs disabled
491 void hrtick_start(struct rq
*rq
, u64 delay
)
493 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
494 HRTIMER_MODE_REL_PINNED
, 0);
497 static inline void init_hrtick(void)
500 #endif /* CONFIG_SMP */
502 static void init_rq_hrtick(struct rq
*rq
)
505 rq
->hrtick_csd_pending
= 0;
507 rq
->hrtick_csd
.flags
= 0;
508 rq
->hrtick_csd
.func
= __hrtick_start
;
509 rq
->hrtick_csd
.info
= rq
;
512 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
513 rq
->hrtick_timer
.function
= hrtick
;
515 #else /* CONFIG_SCHED_HRTICK */
516 static inline void hrtick_clear(struct rq
*rq
)
520 static inline void init_rq_hrtick(struct rq
*rq
)
524 static inline void init_hrtick(void)
527 #endif /* CONFIG_SCHED_HRTICK */
530 * cmpxchg based fetch_or, macro so it works for different integer types
532 #define fetch_or(ptr, val) \
533 ({ typeof(*(ptr)) __old, __val = *(ptr); \
535 __old = cmpxchg((ptr), __val, __val | (val)); \
536 if (__old == __val) \
543 #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
545 * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
546 * this avoids any races wrt polling state changes and thereby avoids
549 static bool set_nr_and_not_polling(struct task_struct
*p
)
551 struct thread_info
*ti
= task_thread_info(p
);
552 return !(fetch_or(&ti
->flags
, _TIF_NEED_RESCHED
) & _TIF_POLLING_NRFLAG
);
556 * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
558 * If this returns true, then the idle task promises to call
559 * sched_ttwu_pending() and reschedule soon.
561 static bool set_nr_if_polling(struct task_struct
*p
)
563 struct thread_info
*ti
= task_thread_info(p
);
564 typeof(ti
->flags
) old
, val
= ACCESS_ONCE(ti
->flags
);
567 if (!(val
& _TIF_POLLING_NRFLAG
))
569 if (val
& _TIF_NEED_RESCHED
)
571 old
= cmpxchg(&ti
->flags
, val
, val
| _TIF_NEED_RESCHED
);
580 static bool set_nr_and_not_polling(struct task_struct
*p
)
582 set_tsk_need_resched(p
);
587 static bool set_nr_if_polling(struct task_struct
*p
)
595 * resched_curr - mark rq's current task 'to be rescheduled now'.
597 * On UP this means the setting of the need_resched flag, on SMP it
598 * might also involve a cross-CPU call to trigger the scheduler on
601 void resched_curr(struct rq
*rq
)
603 struct task_struct
*curr
= rq
->curr
;
606 lockdep_assert_held(&rq
->lock
);
608 if (test_tsk_need_resched(curr
))
613 if (cpu
== smp_processor_id()) {
614 set_tsk_need_resched(curr
);
615 set_preempt_need_resched();
619 if (set_nr_and_not_polling(curr
))
620 smp_send_reschedule(cpu
);
622 trace_sched_wake_idle_without_ipi(cpu
);
625 void resched_cpu(int cpu
)
627 struct rq
*rq
= cpu_rq(cpu
);
630 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
633 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
637 #ifdef CONFIG_NO_HZ_COMMON
639 * In the semi idle case, use the nearest busy cpu for migrating timers
640 * from an idle cpu. This is good for power-savings.
642 * We don't do similar optimization for completely idle system, as
643 * selecting an idle cpu will add more delays to the timers than intended
644 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
646 int get_nohz_timer_target(int pinned
)
648 int cpu
= smp_processor_id();
650 struct sched_domain
*sd
;
652 if (pinned
|| !get_sysctl_timer_migration() || !idle_cpu(cpu
))
656 for_each_domain(cpu
, sd
) {
657 for_each_cpu(i
, sched_domain_span(sd
)) {
669 * When add_timer_on() enqueues a timer into the timer wheel of an
670 * idle CPU then this timer might expire before the next timer event
671 * which is scheduled to wake up that CPU. In case of a completely
672 * idle system the next event might even be infinite time into the
673 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
674 * leaves the inner idle loop so the newly added timer is taken into
675 * account when the CPU goes back to idle and evaluates the timer
676 * wheel for the next timer event.
678 static void wake_up_idle_cpu(int cpu
)
680 struct rq
*rq
= cpu_rq(cpu
);
682 if (cpu
== smp_processor_id())
685 if (set_nr_and_not_polling(rq
->idle
))
686 smp_send_reschedule(cpu
);
688 trace_sched_wake_idle_without_ipi(cpu
);
691 static bool wake_up_full_nohz_cpu(int cpu
)
694 * We just need the target to call irq_exit() and re-evaluate
695 * the next tick. The nohz full kick at least implies that.
696 * If needed we can still optimize that later with an
699 if (tick_nohz_full_cpu(cpu
)) {
700 if (cpu
!= smp_processor_id() ||
701 tick_nohz_tick_stopped())
702 tick_nohz_full_kick_cpu(cpu
);
709 void wake_up_nohz_cpu(int cpu
)
711 if (!wake_up_full_nohz_cpu(cpu
))
712 wake_up_idle_cpu(cpu
);
715 static inline bool got_nohz_idle_kick(void)
717 int cpu
= smp_processor_id();
719 if (!test_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
)))
722 if (idle_cpu(cpu
) && !need_resched())
726 * We can't run Idle Load Balance on this CPU for this time so we
727 * cancel it and clear NOHZ_BALANCE_KICK
729 clear_bit(NOHZ_BALANCE_KICK
, nohz_flags(cpu
));
733 #else /* CONFIG_NO_HZ_COMMON */
735 static inline bool got_nohz_idle_kick(void)
740 #endif /* CONFIG_NO_HZ_COMMON */
742 #ifdef CONFIG_NO_HZ_FULL
743 bool sched_can_stop_tick(void)
746 * More than one running task need preemption.
747 * nr_running update is assumed to be visible
748 * after IPI is sent from wakers.
750 if (this_rq()->nr_running
> 1)
755 #endif /* CONFIG_NO_HZ_FULL */
757 void sched_avg_update(struct rq
*rq
)
759 s64 period
= sched_avg_period();
761 while ((s64
)(rq_clock(rq
) - rq
->age_stamp
) > period
) {
763 * Inline assembly required to prevent the compiler
764 * optimising this loop into a divmod call.
765 * See __iter_div_u64_rem() for another example of this.
767 asm("" : "+rm" (rq
->age_stamp
));
768 rq
->age_stamp
+= period
;
773 #endif /* CONFIG_SMP */
775 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
776 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
778 * Iterate task_group tree rooted at *from, calling @down when first entering a
779 * node and @up when leaving it for the final time.
781 * Caller must hold rcu_lock or sufficient equivalent.
783 int walk_tg_tree_from(struct task_group
*from
,
784 tg_visitor down
, tg_visitor up
, void *data
)
786 struct task_group
*parent
, *child
;
792 ret
= (*down
)(parent
, data
);
795 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
802 ret
= (*up
)(parent
, data
);
803 if (ret
|| parent
== from
)
807 parent
= parent
->parent
;
814 int tg_nop(struct task_group
*tg
, void *data
)
820 static void set_load_weight(struct task_struct
*p
)
822 int prio
= p
->static_prio
- MAX_RT_PRIO
;
823 struct load_weight
*load
= &p
->se
.load
;
826 * SCHED_IDLE tasks get minimal weight:
828 if (p
->policy
== SCHED_IDLE
) {
829 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
830 load
->inv_weight
= WMULT_IDLEPRIO
;
834 load
->weight
= scale_load(prio_to_weight
[prio
]);
835 load
->inv_weight
= prio_to_wmult
[prio
];
838 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
841 sched_info_queued(rq
, p
);
842 p
->sched_class
->enqueue_task(rq
, p
, flags
);
845 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
848 sched_info_dequeued(rq
, p
);
849 p
->sched_class
->dequeue_task(rq
, p
, flags
);
852 void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
854 if (task_contributes_to_load(p
))
855 rq
->nr_uninterruptible
--;
857 enqueue_task(rq
, p
, flags
);
860 void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
862 if (task_contributes_to_load(p
))
863 rq
->nr_uninterruptible
++;
865 dequeue_task(rq
, p
, flags
);
868 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
871 * In theory, the compile should just see 0 here, and optimize out the call
872 * to sched_rt_avg_update. But I don't trust it...
874 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
875 s64 steal
= 0, irq_delta
= 0;
877 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
878 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
881 * Since irq_time is only updated on {soft,}irq_exit, we might run into
882 * this case when a previous update_rq_clock() happened inside a
885 * When this happens, we stop ->clock_task and only update the
886 * prev_irq_time stamp to account for the part that fit, so that a next
887 * update will consume the rest. This ensures ->clock_task is
890 * It does however cause some slight miss-attribution of {soft,}irq
891 * time, a more accurate solution would be to update the irq_time using
892 * the current rq->clock timestamp, except that would require using
895 if (irq_delta
> delta
)
898 rq
->prev_irq_time
+= irq_delta
;
901 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
902 if (static_key_false((¶virt_steal_rq_enabled
))) {
903 steal
= paravirt_steal_clock(cpu_of(rq
));
904 steal
-= rq
->prev_steal_time_rq
;
906 if (unlikely(steal
> delta
))
909 rq
->prev_steal_time_rq
+= steal
;
914 rq
->clock_task
+= delta
;
916 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
917 if ((irq_delta
+ steal
) && sched_feat(NONTASK_CAPACITY
))
918 sched_rt_avg_update(rq
, irq_delta
+ steal
);
922 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
924 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
925 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
929 * Make it appear like a SCHED_FIFO task, its something
930 * userspace knows about and won't get confused about.
932 * Also, it will make PI more or less work without too
933 * much confusion -- but then, stop work should not
934 * rely on PI working anyway.
936 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
938 stop
->sched_class
= &stop_sched_class
;
941 cpu_rq(cpu
)->stop
= stop
;
945 * Reset it back to a normal scheduling class so that
946 * it can die in pieces.
948 old_stop
->sched_class
= &rt_sched_class
;
953 * __normal_prio - return the priority that is based on the static prio
955 static inline int __normal_prio(struct task_struct
*p
)
957 return p
->static_prio
;
961 * Calculate the expected normal priority: i.e. priority
962 * without taking RT-inheritance into account. Might be
963 * boosted by interactivity modifiers. Changes upon fork,
964 * setprio syscalls, and whenever the interactivity
965 * estimator recalculates.
967 static inline int normal_prio(struct task_struct
*p
)
971 if (task_has_dl_policy(p
))
972 prio
= MAX_DL_PRIO
-1;
973 else if (task_has_rt_policy(p
))
974 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
976 prio
= __normal_prio(p
);
981 * Calculate the current priority, i.e. the priority
982 * taken into account by the scheduler. This value might
983 * be boosted by RT tasks, or might be boosted by
984 * interactivity modifiers. Will be RT if the task got
985 * RT-boosted. If not then it returns p->normal_prio.
987 static int effective_prio(struct task_struct
*p
)
989 p
->normal_prio
= normal_prio(p
);
991 * If we are RT tasks or we were boosted to RT priority,
992 * keep the priority unchanged. Otherwise, update priority
993 * to the normal priority:
995 if (!rt_prio(p
->prio
))
996 return p
->normal_prio
;
1001 * task_curr - is this task currently executing on a CPU?
1002 * @p: the task in question.
1004 * Return: 1 if the task is currently executing. 0 otherwise.
1006 inline int task_curr(const struct task_struct
*p
)
1008 return cpu_curr(task_cpu(p
)) == p
;
1012 * Can drop rq->lock because from sched_class::switched_from() methods drop it.
1014 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1015 const struct sched_class
*prev_class
,
1018 if (prev_class
!= p
->sched_class
) {
1019 if (prev_class
->switched_from
)
1020 prev_class
->switched_from(rq
, p
);
1021 /* Possble rq->lock 'hole'. */
1022 p
->sched_class
->switched_to(rq
, p
);
1023 } else if (oldprio
!= p
->prio
|| dl_task(p
))
1024 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
1027 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
1029 const struct sched_class
*class;
1031 if (p
->sched_class
== rq
->curr
->sched_class
) {
1032 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
1034 for_each_class(class) {
1035 if (class == rq
->curr
->sched_class
)
1037 if (class == p
->sched_class
) {
1045 * A queue event has occurred, and we're going to schedule. In
1046 * this case, we can save a useless back to back clock update.
1048 if (task_on_rq_queued(rq
->curr
) && test_tsk_need_resched(rq
->curr
))
1049 rq
->skip_clock_update
= 1;
1053 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1055 #ifdef CONFIG_SCHED_DEBUG
1057 * We should never call set_task_cpu() on a blocked task,
1058 * ttwu() will sort out the placement.
1060 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
1063 #ifdef CONFIG_LOCKDEP
1065 * The caller should hold either p->pi_lock or rq->lock, when changing
1066 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
1068 * sched_move_task() holds both and thus holding either pins the cgroup,
1071 * Furthermore, all task_rq users should acquire both locks, see
1074 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
1075 lockdep_is_held(&task_rq(p
)->lock
)));
1079 trace_sched_migrate_task(p
, new_cpu
);
1081 if (task_cpu(p
) != new_cpu
) {
1082 if (p
->sched_class
->migrate_task_rq
)
1083 p
->sched_class
->migrate_task_rq(p
, new_cpu
);
1084 p
->se
.nr_migrations
++;
1085 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
1088 __set_task_cpu(p
, new_cpu
);
1091 static void __migrate_swap_task(struct task_struct
*p
, int cpu
)
1093 if (task_on_rq_queued(p
)) {
1094 struct rq
*src_rq
, *dst_rq
;
1096 src_rq
= task_rq(p
);
1097 dst_rq
= cpu_rq(cpu
);
1099 deactivate_task(src_rq
, p
, 0);
1100 set_task_cpu(p
, cpu
);
1101 activate_task(dst_rq
, p
, 0);
1102 check_preempt_curr(dst_rq
, p
, 0);
1105 * Task isn't running anymore; make it appear like we migrated
1106 * it before it went to sleep. This means on wakeup we make the
1107 * previous cpu our targer instead of where it really is.
1113 struct migration_swap_arg
{
1114 struct task_struct
*src_task
, *dst_task
;
1115 int src_cpu
, dst_cpu
;
1118 static int migrate_swap_stop(void *data
)
1120 struct migration_swap_arg
*arg
= data
;
1121 struct rq
*src_rq
, *dst_rq
;
1124 src_rq
= cpu_rq(arg
->src_cpu
);
1125 dst_rq
= cpu_rq(arg
->dst_cpu
);
1127 double_raw_lock(&arg
->src_task
->pi_lock
,
1128 &arg
->dst_task
->pi_lock
);
1129 double_rq_lock(src_rq
, dst_rq
);
1130 if (task_cpu(arg
->dst_task
) != arg
->dst_cpu
)
1133 if (task_cpu(arg
->src_task
) != arg
->src_cpu
)
1136 if (!cpumask_test_cpu(arg
->dst_cpu
, tsk_cpus_allowed(arg
->src_task
)))
1139 if (!cpumask_test_cpu(arg
->src_cpu
, tsk_cpus_allowed(arg
->dst_task
)))
1142 __migrate_swap_task(arg
->src_task
, arg
->dst_cpu
);
1143 __migrate_swap_task(arg
->dst_task
, arg
->src_cpu
);
1148 double_rq_unlock(src_rq
, dst_rq
);
1149 raw_spin_unlock(&arg
->dst_task
->pi_lock
);
1150 raw_spin_unlock(&arg
->src_task
->pi_lock
);
1156 * Cross migrate two tasks
1158 int migrate_swap(struct task_struct
*cur
, struct task_struct
*p
)
1160 struct migration_swap_arg arg
;
1163 arg
= (struct migration_swap_arg
){
1165 .src_cpu
= task_cpu(cur
),
1167 .dst_cpu
= task_cpu(p
),
1170 if (arg
.src_cpu
== arg
.dst_cpu
)
1174 * These three tests are all lockless; this is OK since all of them
1175 * will be re-checked with proper locks held further down the line.
1177 if (!cpu_active(arg
.src_cpu
) || !cpu_active(arg
.dst_cpu
))
1180 if (!cpumask_test_cpu(arg
.dst_cpu
, tsk_cpus_allowed(arg
.src_task
)))
1183 if (!cpumask_test_cpu(arg
.src_cpu
, tsk_cpus_allowed(arg
.dst_task
)))
1186 trace_sched_swap_numa(cur
, arg
.src_cpu
, p
, arg
.dst_cpu
);
1187 ret
= stop_two_cpus(arg
.dst_cpu
, arg
.src_cpu
, migrate_swap_stop
, &arg
);
1193 struct migration_arg
{
1194 struct task_struct
*task
;
1198 static int migration_cpu_stop(void *data
);
1201 * wait_task_inactive - wait for a thread to unschedule.
1203 * If @match_state is nonzero, it's the @p->state value just checked and
1204 * not expected to change. If it changes, i.e. @p might have woken up,
1205 * then return zero. When we succeed in waiting for @p to be off its CPU,
1206 * we return a positive number (its total switch count). If a second call
1207 * a short while later returns the same number, the caller can be sure that
1208 * @p has remained unscheduled the whole time.
1210 * The caller must ensure that the task *will* unschedule sometime soon,
1211 * else this function might spin for a *long* time. This function can't
1212 * be called with interrupts off, or it may introduce deadlock with
1213 * smp_call_function() if an IPI is sent by the same process we are
1214 * waiting to become inactive.
1216 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
1218 unsigned long flags
;
1219 int running
, queued
;
1225 * We do the initial early heuristics without holding
1226 * any task-queue locks at all. We'll only try to get
1227 * the runqueue lock when things look like they will
1233 * If the task is actively running on another CPU
1234 * still, just relax and busy-wait without holding
1237 * NOTE! Since we don't hold any locks, it's not
1238 * even sure that "rq" stays as the right runqueue!
1239 * But we don't care, since "task_running()" will
1240 * return false if the runqueue has changed and p
1241 * is actually now running somewhere else!
1243 while (task_running(rq
, p
)) {
1244 if (match_state
&& unlikely(p
->state
!= match_state
))
1250 * Ok, time to look more closely! We need the rq
1251 * lock now, to be *sure*. If we're wrong, we'll
1252 * just go back and repeat.
1254 rq
= task_rq_lock(p
, &flags
);
1255 trace_sched_wait_task(p
);
1256 running
= task_running(rq
, p
);
1257 queued
= task_on_rq_queued(p
);
1259 if (!match_state
|| p
->state
== match_state
)
1260 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
1261 task_rq_unlock(rq
, p
, &flags
);
1264 * If it changed from the expected state, bail out now.
1266 if (unlikely(!ncsw
))
1270 * Was it really running after all now that we
1271 * checked with the proper locks actually held?
1273 * Oops. Go back and try again..
1275 if (unlikely(running
)) {
1281 * It's not enough that it's not actively running,
1282 * it must be off the runqueue _entirely_, and not
1285 * So if it was still runnable (but just not actively
1286 * running right now), it's preempted, and we should
1287 * yield - it could be a while.
1289 if (unlikely(queued
)) {
1290 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
1292 set_current_state(TASK_UNINTERRUPTIBLE
);
1293 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
1298 * Ahh, all good. It wasn't running, and it wasn't
1299 * runnable, which means that it will never become
1300 * running in the future either. We're all done!
1309 * kick_process - kick a running thread to enter/exit the kernel
1310 * @p: the to-be-kicked thread
1312 * Cause a process which is running on another CPU to enter
1313 * kernel-mode, without any delay. (to get signals handled.)
1315 * NOTE: this function doesn't have to take the runqueue lock,
1316 * because all it wants to ensure is that the remote task enters
1317 * the kernel. If the IPI races and the task has been migrated
1318 * to another CPU then no harm is done and the purpose has been
1321 void kick_process(struct task_struct
*p
)
1327 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1328 smp_send_reschedule(cpu
);
1331 EXPORT_SYMBOL_GPL(kick_process
);
1332 #endif /* CONFIG_SMP */
1336 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
1338 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
1340 int nid
= cpu_to_node(cpu
);
1341 const struct cpumask
*nodemask
= NULL
;
1342 enum { cpuset
, possible
, fail
} state
= cpuset
;
1346 * If the node that the cpu is on has been offlined, cpu_to_node()
1347 * will return -1. There is no cpu on the node, and we should
1348 * select the cpu on the other node.
1351 nodemask
= cpumask_of_node(nid
);
1353 /* Look for allowed, online CPU in same node. */
1354 for_each_cpu(dest_cpu
, nodemask
) {
1355 if (!cpu_online(dest_cpu
))
1357 if (!cpu_active(dest_cpu
))
1359 if (cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
1365 /* Any allowed, online CPU? */
1366 for_each_cpu(dest_cpu
, tsk_cpus_allowed(p
)) {
1367 if (!cpu_online(dest_cpu
))
1369 if (!cpu_active(dest_cpu
))
1376 /* No more Mr. Nice Guy. */
1377 cpuset_cpus_allowed_fallback(p
);
1382 do_set_cpus_allowed(p
, cpu_possible_mask
);
1393 if (state
!= cpuset
) {
1395 * Don't tell them about moving exiting tasks or
1396 * kernel threads (both mm NULL), since they never
1399 if (p
->mm
&& printk_ratelimit()) {
1400 printk_deferred("process %d (%s) no longer affine to cpu%d\n",
1401 task_pid_nr(p
), p
->comm
, cpu
);
1409 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
1412 int select_task_rq(struct task_struct
*p
, int cpu
, int sd_flags
, int wake_flags
)
1414 if (p
->nr_cpus_allowed
> 1)
1415 cpu
= p
->sched_class
->select_task_rq(p
, cpu
, sd_flags
, wake_flags
);
1418 * In order not to call set_task_cpu() on a blocking task we need
1419 * to rely on ttwu() to place the task on a valid ->cpus_allowed
1422 * Since this is common to all placement strategies, this lives here.
1424 * [ this allows ->select_task() to simply return task_cpu(p) and
1425 * not worry about this generic constraint ]
1427 if (unlikely(!cpumask_test_cpu(cpu
, tsk_cpus_allowed(p
)) ||
1429 cpu
= select_fallback_rq(task_cpu(p
), p
);
1434 static void update_avg(u64
*avg
, u64 sample
)
1436 s64 diff
= sample
- *avg
;
1442 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
1444 #ifdef CONFIG_SCHEDSTATS
1445 struct rq
*rq
= this_rq();
1448 int this_cpu
= smp_processor_id();
1450 if (cpu
== this_cpu
) {
1451 schedstat_inc(rq
, ttwu_local
);
1452 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
1454 struct sched_domain
*sd
;
1456 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
1458 for_each_domain(this_cpu
, sd
) {
1459 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
1460 schedstat_inc(sd
, ttwu_wake_remote
);
1467 if (wake_flags
& WF_MIGRATED
)
1468 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
1470 #endif /* CONFIG_SMP */
1472 schedstat_inc(rq
, ttwu_count
);
1473 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
1475 if (wake_flags
& WF_SYNC
)
1476 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
1478 #endif /* CONFIG_SCHEDSTATS */
1481 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
1483 activate_task(rq
, p
, en_flags
);
1484 p
->on_rq
= TASK_ON_RQ_QUEUED
;
1486 /* if a worker is waking up, notify workqueue */
1487 if (p
->flags
& PF_WQ_WORKER
)
1488 wq_worker_waking_up(p
, cpu_of(rq
));
1492 * Mark the task runnable and perform wakeup-preemption.
1495 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1497 check_preempt_curr(rq
, p
, wake_flags
);
1498 trace_sched_wakeup(p
, true);
1500 p
->state
= TASK_RUNNING
;
1502 if (p
->sched_class
->task_woken
)
1503 p
->sched_class
->task_woken(rq
, p
);
1505 if (rq
->idle_stamp
) {
1506 u64 delta
= rq_clock(rq
) - rq
->idle_stamp
;
1507 u64 max
= 2*rq
->max_idle_balance_cost
;
1509 update_avg(&rq
->avg_idle
, delta
);
1511 if (rq
->avg_idle
> max
)
1520 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
1523 if (p
->sched_contributes_to_load
)
1524 rq
->nr_uninterruptible
--;
1527 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
1528 ttwu_do_wakeup(rq
, p
, wake_flags
);
1532 * Called in case the task @p isn't fully descheduled from its runqueue,
1533 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
1534 * since all we need to do is flip p->state to TASK_RUNNING, since
1535 * the task is still ->on_rq.
1537 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
1542 rq
= __task_rq_lock(p
);
1543 if (task_on_rq_queued(p
)) {
1544 /* check_preempt_curr() may use rq clock */
1545 update_rq_clock(rq
);
1546 ttwu_do_wakeup(rq
, p
, wake_flags
);
1549 __task_rq_unlock(rq
);
1555 void sched_ttwu_pending(void)
1557 struct rq
*rq
= this_rq();
1558 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
1559 struct task_struct
*p
;
1560 unsigned long flags
;
1565 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1568 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
1569 llist
= llist_next(llist
);
1570 ttwu_do_activate(rq
, p
, 0);
1573 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1576 void scheduler_ipi(void)
1579 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1580 * TIF_NEED_RESCHED remotely (for the first time) will also send
1583 preempt_fold_need_resched();
1585 if (llist_empty(&this_rq()->wake_list
) && !got_nohz_idle_kick())
1589 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
1590 * traditionally all their work was done from the interrupt return
1591 * path. Now that we actually do some work, we need to make sure
1594 * Some archs already do call them, luckily irq_enter/exit nest
1597 * Arguably we should visit all archs and update all handlers,
1598 * however a fair share of IPIs are still resched only so this would
1599 * somewhat pessimize the simple resched case.
1602 sched_ttwu_pending();
1605 * Check if someone kicked us for doing the nohz idle load balance.
1607 if (unlikely(got_nohz_idle_kick())) {
1608 this_rq()->idle_balance
= 1;
1609 raise_softirq_irqoff(SCHED_SOFTIRQ
);
1614 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
1616 struct rq
*rq
= cpu_rq(cpu
);
1618 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
)) {
1619 if (!set_nr_if_polling(rq
->idle
))
1620 smp_send_reschedule(cpu
);
1622 trace_sched_wake_idle_without_ipi(cpu
);
1626 void wake_up_if_idle(int cpu
)
1628 struct rq
*rq
= cpu_rq(cpu
);
1629 unsigned long flags
;
1633 if (!is_idle_task(rcu_dereference(rq
->curr
)))
1636 if (set_nr_if_polling(rq
->idle
)) {
1637 trace_sched_wake_idle_without_ipi(cpu
);
1639 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1640 if (is_idle_task(rq
->curr
))
1641 smp_send_reschedule(cpu
);
1642 /* Else cpu is not in idle, do nothing here */
1643 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1650 bool cpus_share_cache(int this_cpu
, int that_cpu
)
1652 return per_cpu(sd_llc_id
, this_cpu
) == per_cpu(sd_llc_id
, that_cpu
);
1654 #endif /* CONFIG_SMP */
1656 static void ttwu_queue(struct task_struct
*p
, int cpu
)
1658 struct rq
*rq
= cpu_rq(cpu
);
1660 #if defined(CONFIG_SMP)
1661 if (sched_feat(TTWU_QUEUE
) && !cpus_share_cache(smp_processor_id(), cpu
)) {
1662 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
1663 ttwu_queue_remote(p
, cpu
);
1668 raw_spin_lock(&rq
->lock
);
1669 ttwu_do_activate(rq
, p
, 0);
1670 raw_spin_unlock(&rq
->lock
);
1674 * try_to_wake_up - wake up a thread
1675 * @p: the thread to be awakened
1676 * @state: the mask of task states that can be woken
1677 * @wake_flags: wake modifier flags (WF_*)
1679 * Put it on the run-queue if it's not already there. The "current"
1680 * thread is always on the run-queue (except when the actual
1681 * re-schedule is in progress), and as such you're allowed to do
1682 * the simpler "current->state = TASK_RUNNING" to mark yourself
1683 * runnable without the overhead of this.
1685 * Return: %true if @p was woken up, %false if it was already running.
1686 * or @state didn't match @p's state.
1689 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
1691 unsigned long flags
;
1692 int cpu
, success
= 0;
1695 * If we are going to wake up a thread waiting for CONDITION we
1696 * need to ensure that CONDITION=1 done by the caller can not be
1697 * reordered with p->state check below. This pairs with mb() in
1698 * set_current_state() the waiting thread does.
1700 smp_mb__before_spinlock();
1701 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1702 if (!(p
->state
& state
))
1705 success
= 1; /* we're going to change ->state */
1708 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
1713 * If the owning (remote) cpu is still in the middle of schedule() with
1714 * this task as prev, wait until its done referencing the task.
1719 * Pairs with the smp_wmb() in finish_lock_switch().
1723 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
1724 p
->state
= TASK_WAKING
;
1726 if (p
->sched_class
->task_waking
)
1727 p
->sched_class
->task_waking(p
);
1729 cpu
= select_task_rq(p
, p
->wake_cpu
, SD_BALANCE_WAKE
, wake_flags
);
1730 if (task_cpu(p
) != cpu
) {
1731 wake_flags
|= WF_MIGRATED
;
1732 set_task_cpu(p
, cpu
);
1734 #endif /* CONFIG_SMP */
1738 ttwu_stat(p
, cpu
, wake_flags
);
1740 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1746 * try_to_wake_up_local - try to wake up a local task with rq lock held
1747 * @p: the thread to be awakened
1749 * Put @p on the run-queue if it's not already there. The caller must
1750 * ensure that this_rq() is locked, @p is bound to this_rq() and not
1753 static void try_to_wake_up_local(struct task_struct
*p
)
1755 struct rq
*rq
= task_rq(p
);
1757 if (WARN_ON_ONCE(rq
!= this_rq()) ||
1758 WARN_ON_ONCE(p
== current
))
1761 lockdep_assert_held(&rq
->lock
);
1763 if (!raw_spin_trylock(&p
->pi_lock
)) {
1764 raw_spin_unlock(&rq
->lock
);
1765 raw_spin_lock(&p
->pi_lock
);
1766 raw_spin_lock(&rq
->lock
);
1769 if (!(p
->state
& TASK_NORMAL
))
1772 if (!task_on_rq_queued(p
))
1773 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
1775 ttwu_do_wakeup(rq
, p
, 0);
1776 ttwu_stat(p
, smp_processor_id(), 0);
1778 raw_spin_unlock(&p
->pi_lock
);
1782 * wake_up_process - Wake up a specific process
1783 * @p: The process to be woken up.
1785 * Attempt to wake up the nominated process and move it to the set of runnable
1788 * Return: 1 if the process was woken up, 0 if it was already running.
1790 * It may be assumed that this function implies a write memory barrier before
1791 * changing the task state if and only if any tasks are woken up.
1793 int wake_up_process(struct task_struct
*p
)
1795 WARN_ON(task_is_stopped_or_traced(p
));
1796 return try_to_wake_up(p
, TASK_NORMAL
, 0);
1798 EXPORT_SYMBOL(wake_up_process
);
1800 int wake_up_state(struct task_struct
*p
, unsigned int state
)
1802 return try_to_wake_up(p
, state
, 0);
1806 * This function clears the sched_dl_entity static params.
1808 void __dl_clear_params(struct task_struct
*p
)
1810 struct sched_dl_entity
*dl_se
= &p
->dl
;
1812 dl_se
->dl_runtime
= 0;
1813 dl_se
->dl_deadline
= 0;
1814 dl_se
->dl_period
= 0;
1818 dl_se
->dl_throttled
= 0;
1820 dl_se
->dl_yielded
= 0;
1824 * Perform scheduler related setup for a newly forked process p.
1825 * p is forked by current.
1827 * __sched_fork() is basic setup used by init_idle() too:
1829 static void __sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1834 p
->se
.exec_start
= 0;
1835 p
->se
.sum_exec_runtime
= 0;
1836 p
->se
.prev_sum_exec_runtime
= 0;
1837 p
->se
.nr_migrations
= 0;
1839 INIT_LIST_HEAD(&p
->se
.group_node
);
1841 #ifdef CONFIG_SCHEDSTATS
1842 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
1845 RB_CLEAR_NODE(&p
->dl
.rb_node
);
1846 init_dl_task_timer(&p
->dl
);
1847 __dl_clear_params(p
);
1849 INIT_LIST_HEAD(&p
->rt
.run_list
);
1851 #ifdef CONFIG_PREEMPT_NOTIFIERS
1852 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
1855 #ifdef CONFIG_NUMA_BALANCING
1856 if (p
->mm
&& atomic_read(&p
->mm
->mm_users
) == 1) {
1857 p
->mm
->numa_next_scan
= jiffies
+ msecs_to_jiffies(sysctl_numa_balancing_scan_delay
);
1858 p
->mm
->numa_scan_seq
= 0;
1861 if (clone_flags
& CLONE_VM
)
1862 p
->numa_preferred_nid
= current
->numa_preferred_nid
;
1864 p
->numa_preferred_nid
= -1;
1866 p
->node_stamp
= 0ULL;
1867 p
->numa_scan_seq
= p
->mm
? p
->mm
->numa_scan_seq
: 0;
1868 p
->numa_scan_period
= sysctl_numa_balancing_scan_delay
;
1869 p
->numa_work
.next
= &p
->numa_work
;
1870 p
->numa_faults
= NULL
;
1871 p
->last_task_numa_placement
= 0;
1872 p
->last_sum_exec_runtime
= 0;
1874 p
->numa_group
= NULL
;
1875 #endif /* CONFIG_NUMA_BALANCING */
1878 #ifdef CONFIG_NUMA_BALANCING
1879 #ifdef CONFIG_SCHED_DEBUG
1880 void set_numabalancing_state(bool enabled
)
1883 sched_feat_set("NUMA");
1885 sched_feat_set("NO_NUMA");
1888 __read_mostly
bool numabalancing_enabled
;
1890 void set_numabalancing_state(bool enabled
)
1892 numabalancing_enabled
= enabled
;
1894 #endif /* CONFIG_SCHED_DEBUG */
1896 #ifdef CONFIG_PROC_SYSCTL
1897 int sysctl_numa_balancing(struct ctl_table
*table
, int write
,
1898 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
1902 int state
= numabalancing_enabled
;
1904 if (write
&& !capable(CAP_SYS_ADMIN
))
1909 err
= proc_dointvec_minmax(&t
, write
, buffer
, lenp
, ppos
);
1913 set_numabalancing_state(state
);
1920 * fork()/clone()-time setup:
1922 int sched_fork(unsigned long clone_flags
, struct task_struct
*p
)
1924 unsigned long flags
;
1925 int cpu
= get_cpu();
1927 __sched_fork(clone_flags
, p
);
1929 * We mark the process as running here. This guarantees that
1930 * nobody will actually run it, and a signal or other external
1931 * event cannot wake it up and insert it on the runqueue either.
1933 p
->state
= TASK_RUNNING
;
1936 * Make sure we do not leak PI boosting priority to the child.
1938 p
->prio
= current
->normal_prio
;
1941 * Revert to default priority/policy on fork if requested.
1943 if (unlikely(p
->sched_reset_on_fork
)) {
1944 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
1945 p
->policy
= SCHED_NORMAL
;
1946 p
->static_prio
= NICE_TO_PRIO(0);
1948 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
1949 p
->static_prio
= NICE_TO_PRIO(0);
1951 p
->prio
= p
->normal_prio
= __normal_prio(p
);
1955 * We don't need the reset flag anymore after the fork. It has
1956 * fulfilled its duty:
1958 p
->sched_reset_on_fork
= 0;
1961 if (dl_prio(p
->prio
)) {
1964 } else if (rt_prio(p
->prio
)) {
1965 p
->sched_class
= &rt_sched_class
;
1967 p
->sched_class
= &fair_sched_class
;
1970 if (p
->sched_class
->task_fork
)
1971 p
->sched_class
->task_fork(p
);
1974 * The child is not yet in the pid-hash so no cgroup attach races,
1975 * and the cgroup is pinned to this child due to cgroup_fork()
1976 * is ran before sched_fork().
1978 * Silence PROVE_RCU.
1980 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
1981 set_task_cpu(p
, cpu
);
1982 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
1984 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
1985 if (likely(sched_info_on()))
1986 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
1988 #if defined(CONFIG_SMP)
1991 init_task_preempt_count(p
);
1993 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
1994 RB_CLEAR_NODE(&p
->pushable_dl_tasks
);
2001 unsigned long to_ratio(u64 period
, u64 runtime
)
2003 if (runtime
== RUNTIME_INF
)
2007 * Doing this here saves a lot of checks in all
2008 * the calling paths, and returning zero seems
2009 * safe for them anyway.
2014 return div64_u64(runtime
<< 20, period
);
2018 inline struct dl_bw
*dl_bw_of(int i
)
2020 rcu_lockdep_assert(rcu_read_lock_sched_held(),
2021 "sched RCU must be held");
2022 return &cpu_rq(i
)->rd
->dl_bw
;
2025 static inline int dl_bw_cpus(int i
)
2027 struct root_domain
*rd
= cpu_rq(i
)->rd
;
2030 rcu_lockdep_assert(rcu_read_lock_sched_held(),
2031 "sched RCU must be held");
2032 for_each_cpu_and(i
, rd
->span
, cpu_active_mask
)
2038 inline struct dl_bw
*dl_bw_of(int i
)
2040 return &cpu_rq(i
)->dl
.dl_bw
;
2043 static inline int dl_bw_cpus(int i
)
2050 * We must be sure that accepting a new task (or allowing changing the
2051 * parameters of an existing one) is consistent with the bandwidth
2052 * constraints. If yes, this function also accordingly updates the currently
2053 * allocated bandwidth to reflect the new situation.
2055 * This function is called while holding p's rq->lock.
2057 * XXX we should delay bw change until the task's 0-lag point, see
2060 static int dl_overflow(struct task_struct
*p
, int policy
,
2061 const struct sched_attr
*attr
)
2064 struct dl_bw
*dl_b
= dl_bw_of(task_cpu(p
));
2065 u64 period
= attr
->sched_period
?: attr
->sched_deadline
;
2066 u64 runtime
= attr
->sched_runtime
;
2067 u64 new_bw
= dl_policy(policy
) ? to_ratio(period
, runtime
) : 0;
2070 if (new_bw
== p
->dl
.dl_bw
)
2074 * Either if a task, enters, leave, or stays -deadline but changes
2075 * its parameters, we may need to update accordingly the total
2076 * allocated bandwidth of the container.
2078 raw_spin_lock(&dl_b
->lock
);
2079 cpus
= dl_bw_cpus(task_cpu(p
));
2080 if (dl_policy(policy
) && !task_has_dl_policy(p
) &&
2081 !__dl_overflow(dl_b
, cpus
, 0, new_bw
)) {
2082 __dl_add(dl_b
, new_bw
);
2084 } else if (dl_policy(policy
) && task_has_dl_policy(p
) &&
2085 !__dl_overflow(dl_b
, cpus
, p
->dl
.dl_bw
, new_bw
)) {
2086 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2087 __dl_add(dl_b
, new_bw
);
2089 } else if (!dl_policy(policy
) && task_has_dl_policy(p
)) {
2090 __dl_clear(dl_b
, p
->dl
.dl_bw
);
2093 raw_spin_unlock(&dl_b
->lock
);
2098 extern void init_dl_bw(struct dl_bw
*dl_b
);
2101 * wake_up_new_task - wake up a newly created task for the first time.
2103 * This function will do some initial scheduler statistics housekeeping
2104 * that must be done for every newly created context, then puts the task
2105 * on the runqueue and wakes it.
2107 void wake_up_new_task(struct task_struct
*p
)
2109 unsigned long flags
;
2112 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2115 * Fork balancing, do it here and not earlier because:
2116 * - cpus_allowed can change in the fork path
2117 * - any previously selected cpu might disappear through hotplug
2119 set_task_cpu(p
, select_task_rq(p
, task_cpu(p
), SD_BALANCE_FORK
, 0));
2122 /* Initialize new task's runnable average */
2123 init_task_runnable_average(p
);
2124 rq
= __task_rq_lock(p
);
2125 activate_task(rq
, p
, 0);
2126 p
->on_rq
= TASK_ON_RQ_QUEUED
;
2127 trace_sched_wakeup_new(p
, true);
2128 check_preempt_curr(rq
, p
, WF_FORK
);
2130 if (p
->sched_class
->task_woken
)
2131 p
->sched_class
->task_woken(rq
, p
);
2133 task_rq_unlock(rq
, p
, &flags
);
2136 #ifdef CONFIG_PREEMPT_NOTIFIERS
2139 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2140 * @notifier: notifier struct to register
2142 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2144 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2146 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2149 * preempt_notifier_unregister - no longer interested in preemption notifications
2150 * @notifier: notifier struct to unregister
2152 * This is safe to call from within a preemption notifier.
2154 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2156 hlist_del(¬ifier
->link
);
2158 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2160 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2162 struct preempt_notifier
*notifier
;
2164 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2165 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2169 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2170 struct task_struct
*next
)
2172 struct preempt_notifier
*notifier
;
2174 hlist_for_each_entry(notifier
, &curr
->preempt_notifiers
, link
)
2175 notifier
->ops
->sched_out(notifier
, next
);
2178 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2180 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2185 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2186 struct task_struct
*next
)
2190 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2193 * prepare_task_switch - prepare to switch tasks
2194 * @rq: the runqueue preparing to switch
2195 * @prev: the current task that is being switched out
2196 * @next: the task we are going to switch to.
2198 * This is called with the rq lock held and interrupts off. It must
2199 * be paired with a subsequent finish_task_switch after the context
2202 * prepare_task_switch sets up locking and calls architecture specific
2206 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2207 struct task_struct
*next
)
2209 trace_sched_switch(prev
, next
);
2210 sched_info_switch(rq
, prev
, next
);
2211 perf_event_task_sched_out(prev
, next
);
2212 fire_sched_out_preempt_notifiers(prev
, next
);
2213 prepare_lock_switch(rq
, next
);
2214 prepare_arch_switch(next
);
2218 * finish_task_switch - clean up after a task-switch
2219 * @prev: the thread we just switched away from.
2221 * finish_task_switch must be called after the context switch, paired
2222 * with a prepare_task_switch call before the context switch.
2223 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2224 * and do any other architecture-specific cleanup actions.
2226 * Note that we may have delayed dropping an mm in context_switch(). If
2227 * so, we finish that here outside of the runqueue lock. (Doing it
2228 * with the lock held can cause deadlocks; see schedule() for
2231 * The context switch have flipped the stack from under us and restored the
2232 * local variables which were saved when this task called schedule() in the
2233 * past. prev == current is still correct but we need to recalculate this_rq
2234 * because prev may have moved to another CPU.
2236 static struct rq
*finish_task_switch(struct task_struct
*prev
)
2237 __releases(rq
->lock
)
2239 struct rq
*rq
= this_rq();
2240 struct mm_struct
*mm
= rq
->prev_mm
;
2246 * A task struct has one reference for the use as "current".
2247 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2248 * schedule one last time. The schedule call will never return, and
2249 * the scheduled task must drop that reference.
2250 * The test for TASK_DEAD must occur while the runqueue locks are
2251 * still held, otherwise prev could be scheduled on another cpu, die
2252 * there before we look at prev->state, and then the reference would
2254 * Manfred Spraul <manfred@colorfullife.com>
2256 prev_state
= prev
->state
;
2257 vtime_task_switch(prev
);
2258 finish_arch_switch(prev
);
2259 perf_event_task_sched_in(prev
, current
);
2260 finish_lock_switch(rq
, prev
);
2261 finish_arch_post_lock_switch();
2263 fire_sched_in_preempt_notifiers(current
);
2266 if (unlikely(prev_state
== TASK_DEAD
)) {
2267 if (prev
->sched_class
->task_dead
)
2268 prev
->sched_class
->task_dead(prev
);
2271 * Remove function-return probe instances associated with this
2272 * task and put them back on the free list.
2274 kprobe_flush_task(prev
);
2275 put_task_struct(prev
);
2278 tick_nohz_task_switch(current
);
2284 /* rq->lock is NOT held, but preemption is disabled */
2285 static inline void post_schedule(struct rq
*rq
)
2287 if (rq
->post_schedule
) {
2288 unsigned long flags
;
2290 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2291 if (rq
->curr
->sched_class
->post_schedule
)
2292 rq
->curr
->sched_class
->post_schedule(rq
);
2293 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2295 rq
->post_schedule
= 0;
2301 static inline void post_schedule(struct rq
*rq
)
2308 * schedule_tail - first thing a freshly forked thread must call.
2309 * @prev: the thread we just switched away from.
2311 asmlinkage __visible
void schedule_tail(struct task_struct
*prev
)
2312 __releases(rq
->lock
)
2316 /* finish_task_switch() drops rq->lock and enables preemtion */
2318 rq
= finish_task_switch(prev
);
2322 if (current
->set_child_tid
)
2323 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2327 * context_switch - switch to the new MM and the new thread's register state.
2329 static inline struct rq
*
2330 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2331 struct task_struct
*next
)
2333 struct mm_struct
*mm
, *oldmm
;
2335 prepare_task_switch(rq
, prev
, next
);
2338 oldmm
= prev
->active_mm
;
2340 * For paravirt, this is coupled with an exit in switch_to to
2341 * combine the page table reload and the switch backend into
2344 arch_start_context_switch(prev
);
2347 next
->active_mm
= oldmm
;
2348 atomic_inc(&oldmm
->mm_count
);
2349 enter_lazy_tlb(oldmm
, next
);
2351 switch_mm(oldmm
, mm
, next
);
2354 prev
->active_mm
= NULL
;
2355 rq
->prev_mm
= oldmm
;
2358 * Since the runqueue lock will be released by the next
2359 * task (which is an invalid locking op but in the case
2360 * of the scheduler it's an obvious special-case), so we
2361 * do an early lockdep release here:
2363 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2365 context_tracking_task_switch(prev
, next
);
2366 /* Here we just switch the register state and the stack. */
2367 switch_to(prev
, next
, prev
);
2370 return finish_task_switch(prev
);
2374 * nr_running and nr_context_switches:
2376 * externally visible scheduler statistics: current number of runnable
2377 * threads, total number of context switches performed since bootup.
2379 unsigned long nr_running(void)
2381 unsigned long i
, sum
= 0;
2383 for_each_online_cpu(i
)
2384 sum
+= cpu_rq(i
)->nr_running
;
2390 * Check if only the current task is running on the cpu.
2392 bool single_task_running(void)
2394 if (cpu_rq(smp_processor_id())->nr_running
== 1)
2399 EXPORT_SYMBOL(single_task_running
);
2401 unsigned long long nr_context_switches(void)
2404 unsigned long long sum
= 0;
2406 for_each_possible_cpu(i
)
2407 sum
+= cpu_rq(i
)->nr_switches
;
2412 unsigned long nr_iowait(void)
2414 unsigned long i
, sum
= 0;
2416 for_each_possible_cpu(i
)
2417 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2422 unsigned long nr_iowait_cpu(int cpu
)
2424 struct rq
*this = cpu_rq(cpu
);
2425 return atomic_read(&this->nr_iowait
);
2428 void get_iowait_load(unsigned long *nr_waiters
, unsigned long *load
)
2430 struct rq
*this = this_rq();
2431 *nr_waiters
= atomic_read(&this->nr_iowait
);
2432 *load
= this->cpu_load
[0];
2438 * sched_exec - execve() is a valuable balancing opportunity, because at
2439 * this point the task has the smallest effective memory and cache footprint.
2441 void sched_exec(void)
2443 struct task_struct
*p
= current
;
2444 unsigned long flags
;
2447 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2448 dest_cpu
= p
->sched_class
->select_task_rq(p
, task_cpu(p
), SD_BALANCE_EXEC
, 0);
2449 if (dest_cpu
== smp_processor_id())
2452 if (likely(cpu_active(dest_cpu
))) {
2453 struct migration_arg arg
= { p
, dest_cpu
};
2455 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2456 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
2460 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2465 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
2466 DEFINE_PER_CPU(struct kernel_cpustat
, kernel_cpustat
);
2468 EXPORT_PER_CPU_SYMBOL(kstat
);
2469 EXPORT_PER_CPU_SYMBOL(kernel_cpustat
);
2472 * Return accounted runtime for the task.
2473 * In case the task is currently running, return the runtime plus current's
2474 * pending runtime that have not been accounted yet.
2476 unsigned long long task_sched_runtime(struct task_struct
*p
)
2478 unsigned long flags
;
2482 #if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
2484 * 64-bit doesn't need locks to atomically read a 64bit value.
2485 * So we have a optimization chance when the task's delta_exec is 0.
2486 * Reading ->on_cpu is racy, but this is ok.
2488 * If we race with it leaving cpu, we'll take a lock. So we're correct.
2489 * If we race with it entering cpu, unaccounted time is 0. This is
2490 * indistinguishable from the read occurring a few cycles earlier.
2491 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
2492 * been accounted, so we're correct here as well.
2494 if (!p
->on_cpu
|| !task_on_rq_queued(p
))
2495 return p
->se
.sum_exec_runtime
;
2498 rq
= task_rq_lock(p
, &flags
);
2500 * Must be ->curr _and_ ->on_rq. If dequeued, we would
2501 * project cycles that may never be accounted to this
2502 * thread, breaking clock_gettime().
2504 if (task_current(rq
, p
) && task_on_rq_queued(p
)) {
2505 update_rq_clock(rq
);
2506 p
->sched_class
->update_curr(rq
);
2508 ns
= p
->se
.sum_exec_runtime
;
2509 task_rq_unlock(rq
, p
, &flags
);
2515 * This function gets called by the timer code, with HZ frequency.
2516 * We call it with interrupts disabled.
2518 void scheduler_tick(void)
2520 int cpu
= smp_processor_id();
2521 struct rq
*rq
= cpu_rq(cpu
);
2522 struct task_struct
*curr
= rq
->curr
;
2526 raw_spin_lock(&rq
->lock
);
2527 update_rq_clock(rq
);
2528 curr
->sched_class
->task_tick(rq
, curr
, 0);
2529 update_cpu_load_active(rq
);
2530 raw_spin_unlock(&rq
->lock
);
2532 perf_event_task_tick();
2535 rq
->idle_balance
= idle_cpu(cpu
);
2536 trigger_load_balance(rq
);
2538 rq_last_tick_reset(rq
);
2541 #ifdef CONFIG_NO_HZ_FULL
2543 * scheduler_tick_max_deferment
2545 * Keep at least one tick per second when a single
2546 * active task is running because the scheduler doesn't
2547 * yet completely support full dynticks environment.
2549 * This makes sure that uptime, CFS vruntime, load
2550 * balancing, etc... continue to move forward, even
2551 * with a very low granularity.
2553 * Return: Maximum deferment in nanoseconds.
2555 u64
scheduler_tick_max_deferment(void)
2557 struct rq
*rq
= this_rq();
2558 unsigned long next
, now
= ACCESS_ONCE(jiffies
);
2560 next
= rq
->last_sched_tick
+ HZ
;
2562 if (time_before_eq(next
, now
))
2565 return jiffies_to_nsecs(next
- now
);
2569 notrace
unsigned long get_parent_ip(unsigned long addr
)
2571 if (in_lock_functions(addr
)) {
2572 addr
= CALLER_ADDR2
;
2573 if (in_lock_functions(addr
))
2574 addr
= CALLER_ADDR3
;
2579 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
2580 defined(CONFIG_PREEMPT_TRACER))
2582 void preempt_count_add(int val
)
2584 #ifdef CONFIG_DEBUG_PREEMPT
2588 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
2591 __preempt_count_add(val
);
2592 #ifdef CONFIG_DEBUG_PREEMPT
2594 * Spinlock count overflowing soon?
2596 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
2599 if (preempt_count() == val
) {
2600 unsigned long ip
= get_parent_ip(CALLER_ADDR1
);
2601 #ifdef CONFIG_DEBUG_PREEMPT
2602 current
->preempt_disable_ip
= ip
;
2604 trace_preempt_off(CALLER_ADDR0
, ip
);
2607 EXPORT_SYMBOL(preempt_count_add
);
2608 NOKPROBE_SYMBOL(preempt_count_add
);
2610 void preempt_count_sub(int val
)
2612 #ifdef CONFIG_DEBUG_PREEMPT
2616 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
2619 * Is the spinlock portion underflowing?
2621 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
2622 !(preempt_count() & PREEMPT_MASK
)))
2626 if (preempt_count() == val
)
2627 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
2628 __preempt_count_sub(val
);
2630 EXPORT_SYMBOL(preempt_count_sub
);
2631 NOKPROBE_SYMBOL(preempt_count_sub
);
2636 * Print scheduling while atomic bug:
2638 static noinline
void __schedule_bug(struct task_struct
*prev
)
2640 if (oops_in_progress
)
2643 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
2644 prev
->comm
, prev
->pid
, preempt_count());
2646 debug_show_held_locks(prev
);
2648 if (irqs_disabled())
2649 print_irqtrace_events(prev
);
2650 #ifdef CONFIG_DEBUG_PREEMPT
2651 if (in_atomic_preempt_off()) {
2652 pr_err("Preemption disabled at:");
2653 print_ip_sym(current
->preempt_disable_ip
);
2658 add_taint(TAINT_WARN
, LOCKDEP_STILL_OK
);
2662 * Various schedule()-time debugging checks and statistics:
2664 static inline void schedule_debug(struct task_struct
*prev
)
2666 #ifdef CONFIG_SCHED_STACK_END_CHECK
2667 BUG_ON(unlikely(task_stack_end_corrupted(prev
)));
2670 * Test if we are atomic. Since do_exit() needs to call into
2671 * schedule() atomically, we ignore that path. Otherwise whine
2672 * if we are scheduling when we should not.
2674 if (unlikely(in_atomic_preempt_off() && prev
->state
!= TASK_DEAD
))
2675 __schedule_bug(prev
);
2678 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
2680 schedstat_inc(this_rq(), sched_count
);
2684 * Pick up the highest-prio task:
2686 static inline struct task_struct
*
2687 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
2689 const struct sched_class
*class = &fair_sched_class
;
2690 struct task_struct
*p
;
2693 * Optimization: we know that if all tasks are in
2694 * the fair class we can call that function directly:
2696 if (likely(prev
->sched_class
== class &&
2697 rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
2698 p
= fair_sched_class
.pick_next_task(rq
, prev
);
2699 if (unlikely(p
== RETRY_TASK
))
2702 /* assumes fair_sched_class->next == idle_sched_class */
2704 p
= idle_sched_class
.pick_next_task(rq
, prev
);
2710 for_each_class(class) {
2711 p
= class->pick_next_task(rq
, prev
);
2713 if (unlikely(p
== RETRY_TASK
))
2719 BUG(); /* the idle class will always have a runnable task */
2723 * __schedule() is the main scheduler function.
2725 * The main means of driving the scheduler and thus entering this function are:
2727 * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
2729 * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
2730 * paths. For example, see arch/x86/entry_64.S.
2732 * To drive preemption between tasks, the scheduler sets the flag in timer
2733 * interrupt handler scheduler_tick().
2735 * 3. Wakeups don't really cause entry into schedule(). They add a
2736 * task to the run-queue and that's it.
2738 * Now, if the new task added to the run-queue preempts the current
2739 * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
2740 * called on the nearest possible occasion:
2742 * - If the kernel is preemptible (CONFIG_PREEMPT=y):
2744 * - in syscall or exception context, at the next outmost
2745 * preempt_enable(). (this might be as soon as the wake_up()'s
2748 * - in IRQ context, return from interrupt-handler to
2749 * preemptible context
2751 * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
2754 * - cond_resched() call
2755 * - explicit schedule() call
2756 * - return from syscall or exception to user-space
2757 * - return from interrupt-handler to user-space
2759 static void __sched
__schedule(void)
2761 struct task_struct
*prev
, *next
;
2762 unsigned long *switch_count
;
2768 cpu
= smp_processor_id();
2770 rcu_note_context_switch();
2773 schedule_debug(prev
);
2775 if (sched_feat(HRTICK
))
2779 * Make sure that signal_pending_state()->signal_pending() below
2780 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
2781 * done by the caller to avoid the race with signal_wake_up().
2783 smp_mb__before_spinlock();
2784 raw_spin_lock_irq(&rq
->lock
);
2786 switch_count
= &prev
->nivcsw
;
2787 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
2788 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
2789 prev
->state
= TASK_RUNNING
;
2791 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
2795 * If a worker went to sleep, notify and ask workqueue
2796 * whether it wants to wake up a task to maintain
2799 if (prev
->flags
& PF_WQ_WORKER
) {
2800 struct task_struct
*to_wakeup
;
2802 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
2804 try_to_wake_up_local(to_wakeup
);
2807 switch_count
= &prev
->nvcsw
;
2810 if (task_on_rq_queued(prev
) || rq
->skip_clock_update
< 0)
2811 update_rq_clock(rq
);
2813 next
= pick_next_task(rq
, prev
);
2814 clear_tsk_need_resched(prev
);
2815 clear_preempt_need_resched();
2816 rq
->skip_clock_update
= 0;
2818 if (likely(prev
!= next
)) {
2823 rq
= context_switch(rq
, prev
, next
); /* unlocks the rq */
2826 raw_spin_unlock_irq(&rq
->lock
);
2830 sched_preempt_enable_no_resched();
2835 static inline void sched_submit_work(struct task_struct
*tsk
)
2837 if (!tsk
->state
|| tsk_is_pi_blocked(tsk
))
2840 * If we are going to sleep and we have plugged IO queued,
2841 * make sure to submit it to avoid deadlocks.
2843 if (blk_needs_flush_plug(tsk
))
2844 blk_schedule_flush_plug(tsk
);
2847 asmlinkage __visible
void __sched
schedule(void)
2849 struct task_struct
*tsk
= current
;
2851 sched_submit_work(tsk
);
2854 EXPORT_SYMBOL(schedule
);
2856 #ifdef CONFIG_CONTEXT_TRACKING
2857 asmlinkage __visible
void __sched
schedule_user(void)
2860 * If we come here after a random call to set_need_resched(),
2861 * or we have been woken up remotely but the IPI has not yet arrived,
2862 * we haven't yet exited the RCU idle mode. Do it here manually until
2863 * we find a better solution.
2865 * NB: There are buggy callers of this function. Ideally we
2866 * should warn if prev_state != IN_USER, but that will trigger
2867 * too frequently to make sense yet.
2869 enum ctx_state prev_state
= exception_enter();
2871 exception_exit(prev_state
);
2876 * schedule_preempt_disabled - called with preemption disabled
2878 * Returns with preemption disabled. Note: preempt_count must be 1
2880 void __sched
schedule_preempt_disabled(void)
2882 sched_preempt_enable_no_resched();
2887 #ifdef CONFIG_PREEMPT
2889 * this is the entry point to schedule() from in-kernel preemption
2890 * off of preempt_enable. Kernel preemptions off return from interrupt
2891 * occur there and call schedule directly.
2893 asmlinkage __visible
void __sched notrace
preempt_schedule(void)
2896 * If there is a non-zero preempt_count or interrupts are disabled,
2897 * we do not want to preempt the current task. Just return..
2899 if (likely(!preemptible()))
2903 __preempt_count_add(PREEMPT_ACTIVE
);
2905 __preempt_count_sub(PREEMPT_ACTIVE
);
2908 * Check again in case we missed a preemption opportunity
2909 * between schedule and now.
2912 } while (need_resched());
2914 NOKPROBE_SYMBOL(preempt_schedule
);
2915 EXPORT_SYMBOL(preempt_schedule
);
2917 #ifdef CONFIG_CONTEXT_TRACKING
2919 * preempt_schedule_context - preempt_schedule called by tracing
2921 * The tracing infrastructure uses preempt_enable_notrace to prevent
2922 * recursion and tracing preempt enabling caused by the tracing
2923 * infrastructure itself. But as tracing can happen in areas coming
2924 * from userspace or just about to enter userspace, a preempt enable
2925 * can occur before user_exit() is called. This will cause the scheduler
2926 * to be called when the system is still in usermode.
2928 * To prevent this, the preempt_enable_notrace will use this function
2929 * instead of preempt_schedule() to exit user context if needed before
2930 * calling the scheduler.
2932 asmlinkage __visible
void __sched notrace
preempt_schedule_context(void)
2934 enum ctx_state prev_ctx
;
2936 if (likely(!preemptible()))
2940 __preempt_count_add(PREEMPT_ACTIVE
);
2942 * Needs preempt disabled in case user_exit() is traced
2943 * and the tracer calls preempt_enable_notrace() causing
2944 * an infinite recursion.
2946 prev_ctx
= exception_enter();
2948 exception_exit(prev_ctx
);
2950 __preempt_count_sub(PREEMPT_ACTIVE
);
2952 } while (need_resched());
2954 EXPORT_SYMBOL_GPL(preempt_schedule_context
);
2955 #endif /* CONFIG_CONTEXT_TRACKING */
2957 #endif /* CONFIG_PREEMPT */
2960 * this is the entry point to schedule() from kernel preemption
2961 * off of irq context.
2962 * Note, that this is called and return with irqs disabled. This will
2963 * protect us against recursive calling from irq.
2965 asmlinkage __visible
void __sched
preempt_schedule_irq(void)
2967 enum ctx_state prev_state
;
2969 /* Catch callers which need to be fixed */
2970 BUG_ON(preempt_count() || !irqs_disabled());
2972 prev_state
= exception_enter();
2975 __preempt_count_add(PREEMPT_ACTIVE
);
2978 local_irq_disable();
2979 __preempt_count_sub(PREEMPT_ACTIVE
);
2982 * Check again in case we missed a preemption opportunity
2983 * between schedule and now.
2986 } while (need_resched());
2988 exception_exit(prev_state
);
2991 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
2994 return try_to_wake_up(curr
->private, mode
, wake_flags
);
2996 EXPORT_SYMBOL(default_wake_function
);
2998 #ifdef CONFIG_RT_MUTEXES
3001 * rt_mutex_setprio - set the current priority of a task
3003 * @prio: prio value (kernel-internal form)
3005 * This function changes the 'effective' priority of a task. It does
3006 * not touch ->normal_prio like __setscheduler().
3008 * Used by the rt_mutex code to implement priority inheritance
3009 * logic. Call site only calls if the priority of the task changed.
3011 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
3013 int oldprio
, queued
, running
, enqueue_flag
= 0;
3015 const struct sched_class
*prev_class
;
3017 BUG_ON(prio
> MAX_PRIO
);
3019 rq
= __task_rq_lock(p
);
3022 * Idle task boosting is a nono in general. There is one
3023 * exception, when PREEMPT_RT and NOHZ is active:
3025 * The idle task calls get_next_timer_interrupt() and holds
3026 * the timer wheel base->lock on the CPU and another CPU wants
3027 * to access the timer (probably to cancel it). We can safely
3028 * ignore the boosting request, as the idle CPU runs this code
3029 * with interrupts disabled and will complete the lock
3030 * protected section without being interrupted. So there is no
3031 * real need to boost.
3033 if (unlikely(p
== rq
->idle
)) {
3034 WARN_ON(p
!= rq
->curr
);
3035 WARN_ON(p
->pi_blocked_on
);
3039 trace_sched_pi_setprio(p
, prio
);
3041 prev_class
= p
->sched_class
;
3042 queued
= task_on_rq_queued(p
);
3043 running
= task_current(rq
, p
);
3045 dequeue_task(rq
, p
, 0);
3047 put_prev_task(rq
, p
);
3050 * Boosting condition are:
3051 * 1. -rt task is running and holds mutex A
3052 * --> -dl task blocks on mutex A
3054 * 2. -dl task is running and holds mutex A
3055 * --> -dl task blocks on mutex A and could preempt the
3058 if (dl_prio(prio
)) {
3059 struct task_struct
*pi_task
= rt_mutex_get_top_task(p
);
3060 if (!dl_prio(p
->normal_prio
) ||
3061 (pi_task
&& dl_entity_preempt(&pi_task
->dl
, &p
->dl
))) {
3062 p
->dl
.dl_boosted
= 1;
3063 p
->dl
.dl_throttled
= 0;
3064 enqueue_flag
= ENQUEUE_REPLENISH
;
3066 p
->dl
.dl_boosted
= 0;
3067 p
->sched_class
= &dl_sched_class
;
3068 } else if (rt_prio(prio
)) {
3069 if (dl_prio(oldprio
))
3070 p
->dl
.dl_boosted
= 0;
3072 enqueue_flag
= ENQUEUE_HEAD
;
3073 p
->sched_class
= &rt_sched_class
;
3075 if (dl_prio(oldprio
))
3076 p
->dl
.dl_boosted
= 0;
3077 p
->sched_class
= &fair_sched_class
;
3083 p
->sched_class
->set_curr_task(rq
);
3085 enqueue_task(rq
, p
, enqueue_flag
);
3087 check_class_changed(rq
, p
, prev_class
, oldprio
);
3089 __task_rq_unlock(rq
);
3093 void set_user_nice(struct task_struct
*p
, long nice
)
3095 int old_prio
, delta
, queued
;
3096 unsigned long flags
;
3099 if (task_nice(p
) == nice
|| nice
< MIN_NICE
|| nice
> MAX_NICE
)
3102 * We have to be careful, if called from sys_setpriority(),
3103 * the task might be in the middle of scheduling on another CPU.
3105 rq
= task_rq_lock(p
, &flags
);
3107 * The RT priorities are set via sched_setscheduler(), but we still
3108 * allow the 'normal' nice value to be set - but as expected
3109 * it wont have any effect on scheduling until the task is
3110 * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR:
3112 if (task_has_dl_policy(p
) || task_has_rt_policy(p
)) {
3113 p
->static_prio
= NICE_TO_PRIO(nice
);
3116 queued
= task_on_rq_queued(p
);
3118 dequeue_task(rq
, p
, 0);
3120 p
->static_prio
= NICE_TO_PRIO(nice
);
3123 p
->prio
= effective_prio(p
);
3124 delta
= p
->prio
- old_prio
;
3127 enqueue_task(rq
, p
, 0);
3129 * If the task increased its priority or is running and
3130 * lowered its priority, then reschedule its CPU:
3132 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
3136 task_rq_unlock(rq
, p
, &flags
);
3138 EXPORT_SYMBOL(set_user_nice
);
3141 * can_nice - check if a task can reduce its nice value
3145 int can_nice(const struct task_struct
*p
, const int nice
)
3147 /* convert nice value [19,-20] to rlimit style value [1,40] */
3148 int nice_rlim
= nice_to_rlimit(nice
);
3150 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
3151 capable(CAP_SYS_NICE
));
3154 #ifdef __ARCH_WANT_SYS_NICE
3157 * sys_nice - change the priority of the current process.
3158 * @increment: priority increment
3160 * sys_setpriority is a more generic, but much slower function that
3161 * does similar things.
3163 SYSCALL_DEFINE1(nice
, int, increment
)
3168 * Setpriority might change our priority at the same moment.
3169 * We don't have to worry. Conceptually one call occurs first
3170 * and we have a single winner.
3172 increment
= clamp(increment
, -NICE_WIDTH
, NICE_WIDTH
);
3173 nice
= task_nice(current
) + increment
;
3175 nice
= clamp_val(nice
, MIN_NICE
, MAX_NICE
);
3176 if (increment
< 0 && !can_nice(current
, nice
))
3179 retval
= security_task_setnice(current
, nice
);
3183 set_user_nice(current
, nice
);
3190 * task_prio - return the priority value of a given task.
3191 * @p: the task in question.
3193 * Return: The priority value as seen by users in /proc.
3194 * RT tasks are offset by -200. Normal tasks are centered
3195 * around 0, value goes from -16 to +15.
3197 int task_prio(const struct task_struct
*p
)
3199 return p
->prio
- MAX_RT_PRIO
;
3203 * idle_cpu - is a given cpu idle currently?
3204 * @cpu: the processor in question.
3206 * Return: 1 if the CPU is currently idle. 0 otherwise.
3208 int idle_cpu(int cpu
)
3210 struct rq
*rq
= cpu_rq(cpu
);
3212 if (rq
->curr
!= rq
->idle
)
3219 if (!llist_empty(&rq
->wake_list
))
3227 * idle_task - return the idle task for a given cpu.
3228 * @cpu: the processor in question.
3230 * Return: The idle task for the cpu @cpu.
3232 struct task_struct
*idle_task(int cpu
)
3234 return cpu_rq(cpu
)->idle
;
3238 * find_process_by_pid - find a process with a matching PID value.
3239 * @pid: the pid in question.
3241 * The task of @pid, if found. %NULL otherwise.
3243 static struct task_struct
*find_process_by_pid(pid_t pid
)
3245 return pid
? find_task_by_vpid(pid
) : current
;
3249 * This function initializes the sched_dl_entity of a newly becoming
3250 * SCHED_DEADLINE task.
3252 * Only the static values are considered here, the actual runtime and the
3253 * absolute deadline will be properly calculated when the task is enqueued
3254 * for the first time with its new policy.
3257 __setparam_dl(struct task_struct
*p
, const struct sched_attr
*attr
)
3259 struct sched_dl_entity
*dl_se
= &p
->dl
;
3261 dl_se
->dl_runtime
= attr
->sched_runtime
;
3262 dl_se
->dl_deadline
= attr
->sched_deadline
;
3263 dl_se
->dl_period
= attr
->sched_period
?: dl_se
->dl_deadline
;
3264 dl_se
->flags
= attr
->sched_flags
;
3265 dl_se
->dl_bw
= to_ratio(dl_se
->dl_period
, dl_se
->dl_runtime
);
3268 * Changing the parameters of a task is 'tricky' and we're not doing
3269 * the correct thing -- also see task_dead_dl() and switched_from_dl().
3271 * What we SHOULD do is delay the bandwidth release until the 0-lag
3272 * point. This would include retaining the task_struct until that time
3273 * and change dl_overflow() to not immediately decrement the current
3276 * Instead we retain the current runtime/deadline and let the new
3277 * parameters take effect after the current reservation period lapses.
3278 * This is safe (albeit pessimistic) because the 0-lag point is always
3279 * before the current scheduling deadline.
3281 * We can still have temporary overloads because we do not delay the
3282 * change in bandwidth until that time; so admission control is
3283 * not on the safe side. It does however guarantee tasks will never
3284 * consume more than promised.
3289 * sched_setparam() passes in -1 for its policy, to let the functions
3290 * it calls know not to change it.
3292 #define SETPARAM_POLICY -1
3294 static void __setscheduler_params(struct task_struct
*p
,
3295 const struct sched_attr
*attr
)
3297 int policy
= attr
->sched_policy
;
3299 if (policy
== SETPARAM_POLICY
)
3304 if (dl_policy(policy
))
3305 __setparam_dl(p
, attr
);
3306 else if (fair_policy(policy
))
3307 p
->static_prio
= NICE_TO_PRIO(attr
->sched_nice
);
3310 * __sched_setscheduler() ensures attr->sched_priority == 0 when
3311 * !rt_policy. Always setting this ensures that things like
3312 * getparam()/getattr() don't report silly values for !rt tasks.
3314 p
->rt_priority
= attr
->sched_priority
;
3315 p
->normal_prio
= normal_prio(p
);
3319 /* Actually do priority change: must hold pi & rq lock. */
3320 static void __setscheduler(struct rq
*rq
, struct task_struct
*p
,
3321 const struct sched_attr
*attr
)
3323 __setscheduler_params(p
, attr
);
3326 * If we get here, there was no pi waiters boosting the
3327 * task. It is safe to use the normal prio.
3329 p
->prio
= normal_prio(p
);
3331 if (dl_prio(p
->prio
))
3332 p
->sched_class
= &dl_sched_class
;
3333 else if (rt_prio(p
->prio
))
3334 p
->sched_class
= &rt_sched_class
;
3336 p
->sched_class
= &fair_sched_class
;
3340 __getparam_dl(struct task_struct
*p
, struct sched_attr
*attr
)
3342 struct sched_dl_entity
*dl_se
= &p
->dl
;
3344 attr
->sched_priority
= p
->rt_priority
;
3345 attr
->sched_runtime
= dl_se
->dl_runtime
;
3346 attr
->sched_deadline
= dl_se
->dl_deadline
;
3347 attr
->sched_period
= dl_se
->dl_period
;
3348 attr
->sched_flags
= dl_se
->flags
;
3352 * This function validates the new parameters of a -deadline task.
3353 * We ask for the deadline not being zero, and greater or equal
3354 * than the runtime, as well as the period of being zero or
3355 * greater than deadline. Furthermore, we have to be sure that
3356 * user parameters are above the internal resolution of 1us (we
3357 * check sched_runtime only since it is always the smaller one) and
3358 * below 2^63 ns (we have to check both sched_deadline and
3359 * sched_period, as the latter can be zero).
3362 __checkparam_dl(const struct sched_attr
*attr
)
3365 if (attr
->sched_deadline
== 0)
3369 * Since we truncate DL_SCALE bits, make sure we're at least
3372 if (attr
->sched_runtime
< (1ULL << DL_SCALE
))
3376 * Since we use the MSB for wrap-around and sign issues, make
3377 * sure it's not set (mind that period can be equal to zero).
3379 if (attr
->sched_deadline
& (1ULL << 63) ||
3380 attr
->sched_period
& (1ULL << 63))
3383 /* runtime <= deadline <= period (if period != 0) */
3384 if ((attr
->sched_period
!= 0 &&
3385 attr
->sched_period
< attr
->sched_deadline
) ||
3386 attr
->sched_deadline
< attr
->sched_runtime
)
3393 * check the target process has a UID that matches the current process's
3395 static bool check_same_owner(struct task_struct
*p
)
3397 const struct cred
*cred
= current_cred(), *pcred
;
3401 pcred
= __task_cred(p
);
3402 match
= (uid_eq(cred
->euid
, pcred
->euid
) ||
3403 uid_eq(cred
->euid
, pcred
->uid
));
3408 static int __sched_setscheduler(struct task_struct
*p
,
3409 const struct sched_attr
*attr
,
3412 int newprio
= dl_policy(attr
->sched_policy
) ? MAX_DL_PRIO
- 1 :
3413 MAX_RT_PRIO
- 1 - attr
->sched_priority
;
3414 int retval
, oldprio
, oldpolicy
= -1, queued
, running
;
3415 int policy
= attr
->sched_policy
;
3416 unsigned long flags
;
3417 const struct sched_class
*prev_class
;
3421 /* may grab non-irq protected spin_locks */
3422 BUG_ON(in_interrupt());
3424 /* double check policy once rq lock held */
3426 reset_on_fork
= p
->sched_reset_on_fork
;
3427 policy
= oldpolicy
= p
->policy
;
3429 reset_on_fork
= !!(attr
->sched_flags
& SCHED_FLAG_RESET_ON_FORK
);
3431 if (policy
!= SCHED_DEADLINE
&&
3432 policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
3433 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
3434 policy
!= SCHED_IDLE
)
3438 if (attr
->sched_flags
& ~(SCHED_FLAG_RESET_ON_FORK
))
3442 * Valid priorities for SCHED_FIFO and SCHED_RR are
3443 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
3444 * SCHED_BATCH and SCHED_IDLE is 0.
3446 if ((p
->mm
&& attr
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
3447 (!p
->mm
&& attr
->sched_priority
> MAX_RT_PRIO
-1))
3449 if ((dl_policy(policy
) && !__checkparam_dl(attr
)) ||
3450 (rt_policy(policy
) != (attr
->sched_priority
!= 0)))
3454 * Allow unprivileged RT tasks to decrease priority:
3456 if (user
&& !capable(CAP_SYS_NICE
)) {
3457 if (fair_policy(policy
)) {
3458 if (attr
->sched_nice
< task_nice(p
) &&
3459 !can_nice(p
, attr
->sched_nice
))
3463 if (rt_policy(policy
)) {
3464 unsigned long rlim_rtprio
=
3465 task_rlimit(p
, RLIMIT_RTPRIO
);
3467 /* can't set/change the rt policy */
3468 if (policy
!= p
->policy
&& !rlim_rtprio
)
3471 /* can't increase priority */
3472 if (attr
->sched_priority
> p
->rt_priority
&&
3473 attr
->sched_priority
> rlim_rtprio
)
3478 * Can't set/change SCHED_DEADLINE policy at all for now
3479 * (safest behavior); in the future we would like to allow
3480 * unprivileged DL tasks to increase their relative deadline
3481 * or reduce their runtime (both ways reducing utilization)
3483 if (dl_policy(policy
))
3487 * Treat SCHED_IDLE as nice 20. Only allow a switch to
3488 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
3490 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
3491 if (!can_nice(p
, task_nice(p
)))
3495 /* can't change other user's priorities */
3496 if (!check_same_owner(p
))
3499 /* Normal users shall not reset the sched_reset_on_fork flag */
3500 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
3505 retval
= security_task_setscheduler(p
);
3511 * make sure no PI-waiters arrive (or leave) while we are
3512 * changing the priority of the task:
3514 * To be able to change p->policy safely, the appropriate
3515 * runqueue lock must be held.
3517 rq
= task_rq_lock(p
, &flags
);
3520 * Changing the policy of the stop threads its a very bad idea
3522 if (p
== rq
->stop
) {
3523 task_rq_unlock(rq
, p
, &flags
);
3528 * If not changing anything there's no need to proceed further,
3529 * but store a possible modification of reset_on_fork.
3531 if (unlikely(policy
== p
->policy
)) {
3532 if (fair_policy(policy
) && attr
->sched_nice
!= task_nice(p
))
3534 if (rt_policy(policy
) && attr
->sched_priority
!= p
->rt_priority
)
3536 if (dl_policy(policy
))
3539 p
->sched_reset_on_fork
= reset_on_fork
;
3540 task_rq_unlock(rq
, p
, &flags
);
3546 #ifdef CONFIG_RT_GROUP_SCHED
3548 * Do not allow realtime tasks into groups that have no runtime
3551 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
3552 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
3553 !task_group_is_autogroup(task_group(p
))) {
3554 task_rq_unlock(rq
, p
, &flags
);
3559 if (dl_bandwidth_enabled() && dl_policy(policy
)) {
3560 cpumask_t
*span
= rq
->rd
->span
;
3563 * Don't allow tasks with an affinity mask smaller than
3564 * the entire root_domain to become SCHED_DEADLINE. We
3565 * will also fail if there's no bandwidth available.
3567 if (!cpumask_subset(span
, &p
->cpus_allowed
) ||
3568 rq
->rd
->dl_bw
.bw
== 0) {
3569 task_rq_unlock(rq
, p
, &flags
);
3576 /* recheck policy now with rq lock held */
3577 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
3578 policy
= oldpolicy
= -1;
3579 task_rq_unlock(rq
, p
, &flags
);
3584 * If setscheduling to SCHED_DEADLINE (or changing the parameters
3585 * of a SCHED_DEADLINE task) we need to check if enough bandwidth
3588 if ((dl_policy(policy
) || dl_task(p
)) && dl_overflow(p
, policy
, attr
)) {
3589 task_rq_unlock(rq
, p
, &flags
);
3593 p
->sched_reset_on_fork
= reset_on_fork
;
3597 * Special case for priority boosted tasks.
3599 * If the new priority is lower or equal (user space view)
3600 * than the current (boosted) priority, we just store the new
3601 * normal parameters and do not touch the scheduler class and
3602 * the runqueue. This will be done when the task deboost
3605 if (rt_mutex_check_prio(p
, newprio
)) {
3606 __setscheduler_params(p
, attr
);
3607 task_rq_unlock(rq
, p
, &flags
);
3611 queued
= task_on_rq_queued(p
);
3612 running
= task_current(rq
, p
);
3614 dequeue_task(rq
, p
, 0);
3616 put_prev_task(rq
, p
);
3618 prev_class
= p
->sched_class
;
3619 __setscheduler(rq
, p
, attr
);
3622 p
->sched_class
->set_curr_task(rq
);
3625 * We enqueue to tail when the priority of a task is
3626 * increased (user space view).
3628 enqueue_task(rq
, p
, oldprio
<= p
->prio
? ENQUEUE_HEAD
: 0);
3631 check_class_changed(rq
, p
, prev_class
, oldprio
);
3632 task_rq_unlock(rq
, p
, &flags
);
3634 rt_mutex_adjust_pi(p
);
3639 static int _sched_setscheduler(struct task_struct
*p
, int policy
,
3640 const struct sched_param
*param
, bool check
)
3642 struct sched_attr attr
= {
3643 .sched_policy
= policy
,
3644 .sched_priority
= param
->sched_priority
,
3645 .sched_nice
= PRIO_TO_NICE(p
->static_prio
),
3648 /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
3649 if ((policy
!= SETPARAM_POLICY
) && (policy
& SCHED_RESET_ON_FORK
)) {
3650 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3651 policy
&= ~SCHED_RESET_ON_FORK
;
3652 attr
.sched_policy
= policy
;
3655 return __sched_setscheduler(p
, &attr
, check
);
3658 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
3659 * @p: the task in question.
3660 * @policy: new policy.
3661 * @param: structure containing the new RT priority.
3663 * Return: 0 on success. An error code otherwise.
3665 * NOTE that the task may be already dead.
3667 int sched_setscheduler(struct task_struct
*p
, int policy
,
3668 const struct sched_param
*param
)
3670 return _sched_setscheduler(p
, policy
, param
, true);
3672 EXPORT_SYMBOL_GPL(sched_setscheduler
);
3674 int sched_setattr(struct task_struct
*p
, const struct sched_attr
*attr
)
3676 return __sched_setscheduler(p
, attr
, true);
3678 EXPORT_SYMBOL_GPL(sched_setattr
);
3681 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
3682 * @p: the task in question.
3683 * @policy: new policy.
3684 * @param: structure containing the new RT priority.
3686 * Just like sched_setscheduler, only don't bother checking if the
3687 * current context has permission. For example, this is needed in
3688 * stop_machine(): we create temporary high priority worker threads,
3689 * but our caller might not have that capability.
3691 * Return: 0 on success. An error code otherwise.
3693 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
3694 const struct sched_param
*param
)
3696 return _sched_setscheduler(p
, policy
, param
, false);
3700 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
3702 struct sched_param lparam
;
3703 struct task_struct
*p
;
3706 if (!param
|| pid
< 0)
3708 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
3713 p
= find_process_by_pid(pid
);
3715 retval
= sched_setscheduler(p
, policy
, &lparam
);
3722 * Mimics kernel/events/core.c perf_copy_attr().
3724 static int sched_copy_attr(struct sched_attr __user
*uattr
,
3725 struct sched_attr
*attr
)
3730 if (!access_ok(VERIFY_WRITE
, uattr
, SCHED_ATTR_SIZE_VER0
))
3734 * zero the full structure, so that a short copy will be nice.
3736 memset(attr
, 0, sizeof(*attr
));
3738 ret
= get_user(size
, &uattr
->size
);
3742 if (size
> PAGE_SIZE
) /* silly large */
3745 if (!size
) /* abi compat */
3746 size
= SCHED_ATTR_SIZE_VER0
;
3748 if (size
< SCHED_ATTR_SIZE_VER0
)
3752 * If we're handed a bigger struct than we know of,
3753 * ensure all the unknown bits are 0 - i.e. new
3754 * user-space does not rely on any kernel feature
3755 * extensions we dont know about yet.
3757 if (size
> sizeof(*attr
)) {
3758 unsigned char __user
*addr
;
3759 unsigned char __user
*end
;
3762 addr
= (void __user
*)uattr
+ sizeof(*attr
);
3763 end
= (void __user
*)uattr
+ size
;
3765 for (; addr
< end
; addr
++) {
3766 ret
= get_user(val
, addr
);
3772 size
= sizeof(*attr
);
3775 ret
= copy_from_user(attr
, uattr
, size
);
3780 * XXX: do we want to be lenient like existing syscalls; or do we want
3781 * to be strict and return an error on out-of-bounds values?
3783 attr
->sched_nice
= clamp(attr
->sched_nice
, MIN_NICE
, MAX_NICE
);
3788 put_user(sizeof(*attr
), &uattr
->size
);
3793 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
3794 * @pid: the pid in question.
3795 * @policy: new policy.
3796 * @param: structure containing the new RT priority.
3798 * Return: 0 on success. An error code otherwise.
3800 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
3801 struct sched_param __user
*, param
)
3803 /* negative values for policy are not valid */
3807 return do_sched_setscheduler(pid
, policy
, param
);
3811 * sys_sched_setparam - set/change the RT priority of a thread
3812 * @pid: the pid in question.
3813 * @param: structure containing the new RT priority.
3815 * Return: 0 on success. An error code otherwise.
3817 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3819 return do_sched_setscheduler(pid
, SETPARAM_POLICY
, param
);
3823 * sys_sched_setattr - same as above, but with extended sched_attr
3824 * @pid: the pid in question.
3825 * @uattr: structure containing the extended parameters.
3826 * @flags: for future extension.
3828 SYSCALL_DEFINE3(sched_setattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3829 unsigned int, flags
)
3831 struct sched_attr attr
;
3832 struct task_struct
*p
;
3835 if (!uattr
|| pid
< 0 || flags
)
3838 retval
= sched_copy_attr(uattr
, &attr
);
3842 if ((int)attr
.sched_policy
< 0)
3847 p
= find_process_by_pid(pid
);
3849 retval
= sched_setattr(p
, &attr
);
3856 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
3857 * @pid: the pid in question.
3859 * Return: On success, the policy of the thread. Otherwise, a negative error
3862 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
3864 struct task_struct
*p
;
3872 p
= find_process_by_pid(pid
);
3874 retval
= security_task_getscheduler(p
);
3877 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
3884 * sys_sched_getparam - get the RT priority of a thread
3885 * @pid: the pid in question.
3886 * @param: structure containing the RT priority.
3888 * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
3891 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
3893 struct sched_param lp
= { .sched_priority
= 0 };
3894 struct task_struct
*p
;
3897 if (!param
|| pid
< 0)
3901 p
= find_process_by_pid(pid
);
3906 retval
= security_task_getscheduler(p
);
3910 if (task_has_rt_policy(p
))
3911 lp
.sched_priority
= p
->rt_priority
;
3915 * This one might sleep, we cannot do it with a spinlock held ...
3917 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
3926 static int sched_read_attr(struct sched_attr __user
*uattr
,
3927 struct sched_attr
*attr
,
3932 if (!access_ok(VERIFY_WRITE
, uattr
, usize
))
3936 * If we're handed a smaller struct than we know of,
3937 * ensure all the unknown bits are 0 - i.e. old
3938 * user-space does not get uncomplete information.
3940 if (usize
< sizeof(*attr
)) {
3941 unsigned char *addr
;
3944 addr
= (void *)attr
+ usize
;
3945 end
= (void *)attr
+ sizeof(*attr
);
3947 for (; addr
< end
; addr
++) {
3955 ret
= copy_to_user(uattr
, attr
, attr
->size
);
3963 * sys_sched_getattr - similar to sched_getparam, but with sched_attr
3964 * @pid: the pid in question.
3965 * @uattr: structure containing the extended parameters.
3966 * @size: sizeof(attr) for fwd/bwd comp.
3967 * @flags: for future extension.
3969 SYSCALL_DEFINE4(sched_getattr
, pid_t
, pid
, struct sched_attr __user
*, uattr
,
3970 unsigned int, size
, unsigned int, flags
)
3972 struct sched_attr attr
= {
3973 .size
= sizeof(struct sched_attr
),
3975 struct task_struct
*p
;
3978 if (!uattr
|| pid
< 0 || size
> PAGE_SIZE
||
3979 size
< SCHED_ATTR_SIZE_VER0
|| flags
)
3983 p
= find_process_by_pid(pid
);
3988 retval
= security_task_getscheduler(p
);
3992 attr
.sched_policy
= p
->policy
;
3993 if (p
->sched_reset_on_fork
)
3994 attr
.sched_flags
|= SCHED_FLAG_RESET_ON_FORK
;
3995 if (task_has_dl_policy(p
))
3996 __getparam_dl(p
, &attr
);
3997 else if (task_has_rt_policy(p
))
3998 attr
.sched_priority
= p
->rt_priority
;
4000 attr
.sched_nice
= task_nice(p
);
4004 retval
= sched_read_attr(uattr
, &attr
, size
);
4012 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4014 cpumask_var_t cpus_allowed
, new_mask
;
4015 struct task_struct
*p
;
4020 p
= find_process_by_pid(pid
);
4026 /* Prevent p going away */
4030 if (p
->flags
& PF_NO_SETAFFINITY
) {
4034 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4038 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4040 goto out_free_cpus_allowed
;
4043 if (!check_same_owner(p
)) {
4045 if (!ns_capable(__task_cred(p
)->user_ns
, CAP_SYS_NICE
)) {
4047 goto out_free_new_mask
;
4052 retval
= security_task_setscheduler(p
);
4054 goto out_free_new_mask
;
4057 cpuset_cpus_allowed(p
, cpus_allowed
);
4058 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4061 * Since bandwidth control happens on root_domain basis,
4062 * if admission test is enabled, we only admit -deadline
4063 * tasks allowed to run on all the CPUs in the task's
4067 if (task_has_dl_policy(p
) && dl_bandwidth_enabled()) {
4069 if (!cpumask_subset(task_rq(p
)->rd
->span
, new_mask
)) {
4072 goto out_free_new_mask
;
4078 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4081 cpuset_cpus_allowed(p
, cpus_allowed
);
4082 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4084 * We must have raced with a concurrent cpuset
4085 * update. Just reset the cpus_allowed to the
4086 * cpuset's cpus_allowed
4088 cpumask_copy(new_mask
, cpus_allowed
);
4093 free_cpumask_var(new_mask
);
4094 out_free_cpus_allowed
:
4095 free_cpumask_var(cpus_allowed
);
4101 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4102 struct cpumask
*new_mask
)
4104 if (len
< cpumask_size())
4105 cpumask_clear(new_mask
);
4106 else if (len
> cpumask_size())
4107 len
= cpumask_size();
4109 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4113 * sys_sched_setaffinity - set the cpu affinity of a process
4114 * @pid: pid of the process
4115 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4116 * @user_mask_ptr: user-space pointer to the new cpu mask
4118 * Return: 0 on success. An error code otherwise.
4120 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4121 unsigned long __user
*, user_mask_ptr
)
4123 cpumask_var_t new_mask
;
4126 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4129 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4131 retval
= sched_setaffinity(pid
, new_mask
);
4132 free_cpumask_var(new_mask
);
4136 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4138 struct task_struct
*p
;
4139 unsigned long flags
;
4145 p
= find_process_by_pid(pid
);
4149 retval
= security_task_getscheduler(p
);
4153 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4154 cpumask_and(mask
, &p
->cpus_allowed
, cpu_active_mask
);
4155 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4164 * sys_sched_getaffinity - get the cpu affinity of a process
4165 * @pid: pid of the process
4166 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4167 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4169 * Return: 0 on success. An error code otherwise.
4171 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4172 unsigned long __user
*, user_mask_ptr
)
4177 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
4179 if (len
& (sizeof(unsigned long)-1))
4182 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4185 ret
= sched_getaffinity(pid
, mask
);
4187 size_t retlen
= min_t(size_t, len
, cpumask_size());
4189 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
4194 free_cpumask_var(mask
);
4200 * sys_sched_yield - yield the current processor to other threads.
4202 * This function yields the current CPU to other tasks. If there are no
4203 * other threads running on this CPU then this function will return.
4207 SYSCALL_DEFINE0(sched_yield
)
4209 struct rq
*rq
= this_rq_lock();
4211 schedstat_inc(rq
, yld_count
);
4212 current
->sched_class
->yield_task(rq
);
4215 * Since we are going to call schedule() anyway, there's
4216 * no need to preempt or enable interrupts:
4218 __release(rq
->lock
);
4219 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4220 do_raw_spin_unlock(&rq
->lock
);
4221 sched_preempt_enable_no_resched();
4228 static void __cond_resched(void)
4230 __preempt_count_add(PREEMPT_ACTIVE
);
4232 __preempt_count_sub(PREEMPT_ACTIVE
);
4235 int __sched
_cond_resched(void)
4237 if (should_resched()) {
4243 EXPORT_SYMBOL(_cond_resched
);
4246 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4247 * call schedule, and on return reacquire the lock.
4249 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4250 * operations here to prevent schedule() from being called twice (once via
4251 * spin_unlock(), once by hand).
4253 int __cond_resched_lock(spinlock_t
*lock
)
4255 int resched
= should_resched();
4258 lockdep_assert_held(lock
);
4260 if (spin_needbreak(lock
) || resched
) {
4271 EXPORT_SYMBOL(__cond_resched_lock
);
4273 int __sched
__cond_resched_softirq(void)
4275 BUG_ON(!in_softirq());
4277 if (should_resched()) {
4285 EXPORT_SYMBOL(__cond_resched_softirq
);
4288 * yield - yield the current processor to other threads.
4290 * Do not ever use this function, there's a 99% chance you're doing it wrong.
4292 * The scheduler is at all times free to pick the calling task as the most
4293 * eligible task to run, if removing the yield() call from your code breaks
4294 * it, its already broken.
4296 * Typical broken usage is:
4301 * where one assumes that yield() will let 'the other' process run that will
4302 * make event true. If the current task is a SCHED_FIFO task that will never
4303 * happen. Never use yield() as a progress guarantee!!
4305 * If you want to use yield() to wait for something, use wait_event().
4306 * If you want to use yield() to be 'nice' for others, use cond_resched().
4307 * If you still want to use yield(), do not!
4309 void __sched
yield(void)
4311 set_current_state(TASK_RUNNING
);
4314 EXPORT_SYMBOL(yield
);
4317 * yield_to - yield the current processor to another thread in
4318 * your thread group, or accelerate that thread toward the
4319 * processor it's on.
4321 * @preempt: whether task preemption is allowed or not
4323 * It's the caller's job to ensure that the target task struct
4324 * can't go away on us before we can do any checks.
4327 * true (>0) if we indeed boosted the target task.
4328 * false (0) if we failed to boost the target.
4329 * -ESRCH if there's no task to yield to.
4331 int __sched
yield_to(struct task_struct
*p
, bool preempt
)
4333 struct task_struct
*curr
= current
;
4334 struct rq
*rq
, *p_rq
;
4335 unsigned long flags
;
4338 local_irq_save(flags
);
4344 * If we're the only runnable task on the rq and target rq also
4345 * has only one task, there's absolutely no point in yielding.
4347 if (rq
->nr_running
== 1 && p_rq
->nr_running
== 1) {
4352 double_rq_lock(rq
, p_rq
);
4353 if (task_rq(p
) != p_rq
) {
4354 double_rq_unlock(rq
, p_rq
);
4358 if (!curr
->sched_class
->yield_to_task
)
4361 if (curr
->sched_class
!= p
->sched_class
)
4364 if (task_running(p_rq
, p
) || p
->state
)
4367 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
4369 schedstat_inc(rq
, yld_count
);
4371 * Make p's CPU reschedule; pick_next_entity takes care of
4374 if (preempt
&& rq
!= p_rq
)
4379 double_rq_unlock(rq
, p_rq
);
4381 local_irq_restore(flags
);
4388 EXPORT_SYMBOL_GPL(yield_to
);
4391 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4392 * that process accounting knows that this is a task in IO wait state.
4394 void __sched
io_schedule(void)
4396 struct rq
*rq
= raw_rq();
4398 delayacct_blkio_start();
4399 atomic_inc(&rq
->nr_iowait
);
4400 blk_flush_plug(current
);
4401 current
->in_iowait
= 1;
4403 current
->in_iowait
= 0;
4404 atomic_dec(&rq
->nr_iowait
);
4405 delayacct_blkio_end();
4407 EXPORT_SYMBOL(io_schedule
);
4409 long __sched
io_schedule_timeout(long timeout
)
4411 struct rq
*rq
= raw_rq();
4414 delayacct_blkio_start();
4415 atomic_inc(&rq
->nr_iowait
);
4416 blk_flush_plug(current
);
4417 current
->in_iowait
= 1;
4418 ret
= schedule_timeout(timeout
);
4419 current
->in_iowait
= 0;
4420 atomic_dec(&rq
->nr_iowait
);
4421 delayacct_blkio_end();
4426 * sys_sched_get_priority_max - return maximum RT priority.
4427 * @policy: scheduling class.
4429 * Return: On success, this syscall returns the maximum
4430 * rt_priority that can be used by a given scheduling class.
4431 * On failure, a negative error code is returned.
4433 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
4440 ret
= MAX_USER_RT_PRIO
-1;
4442 case SCHED_DEADLINE
:
4453 * sys_sched_get_priority_min - return minimum RT priority.
4454 * @policy: scheduling class.
4456 * Return: On success, this syscall returns the minimum
4457 * rt_priority that can be used by a given scheduling class.
4458 * On failure, a negative error code is returned.
4460 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
4469 case SCHED_DEADLINE
:
4479 * sys_sched_rr_get_interval - return the default timeslice of a process.
4480 * @pid: pid of the process.
4481 * @interval: userspace pointer to the timeslice value.
4483 * this syscall writes the default timeslice value of a given process
4484 * into the user-space timespec buffer. A value of '0' means infinity.
4486 * Return: On success, 0 and the timeslice is in @interval. Otherwise,
4489 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
4490 struct timespec __user
*, interval
)
4492 struct task_struct
*p
;
4493 unsigned int time_slice
;
4494 unsigned long flags
;
4504 p
= find_process_by_pid(pid
);
4508 retval
= security_task_getscheduler(p
);
4512 rq
= task_rq_lock(p
, &flags
);
4514 if (p
->sched_class
->get_rr_interval
)
4515 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
4516 task_rq_unlock(rq
, p
, &flags
);
4519 jiffies_to_timespec(time_slice
, &t
);
4520 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
4528 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
4530 void sched_show_task(struct task_struct
*p
)
4532 unsigned long free
= 0;
4536 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
4537 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
4538 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
4539 #if BITS_PER_LONG == 32
4540 if (state
== TASK_RUNNING
)
4541 printk(KERN_CONT
" running ");
4543 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
4545 if (state
== TASK_RUNNING
)
4546 printk(KERN_CONT
" running task ");
4548 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
4550 #ifdef CONFIG_DEBUG_STACK_USAGE
4551 free
= stack_not_used(p
);
4556 ppid
= task_pid_nr(rcu_dereference(p
->real_parent
));
4558 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
4559 task_pid_nr(p
), ppid
,
4560 (unsigned long)task_thread_info(p
)->flags
);
4562 print_worker_info(KERN_INFO
, p
);
4563 show_stack(p
, NULL
);
4566 void show_state_filter(unsigned long state_filter
)
4568 struct task_struct
*g
, *p
;
4570 #if BITS_PER_LONG == 32
4572 " task PC stack pid father\n");
4575 " task PC stack pid father\n");
4578 for_each_process_thread(g
, p
) {
4580 * reset the NMI-timeout, listing all files on a slow
4581 * console might take a lot of time:
4583 touch_nmi_watchdog();
4584 if (!state_filter
|| (p
->state
& state_filter
))
4588 touch_all_softlockup_watchdogs();
4590 #ifdef CONFIG_SCHED_DEBUG
4591 sysrq_sched_debug_show();
4595 * Only show locks if all tasks are dumped:
4598 debug_show_all_locks();
4601 void init_idle_bootup_task(struct task_struct
*idle
)
4603 idle
->sched_class
= &idle_sched_class
;
4607 * init_idle - set up an idle thread for a given CPU
4608 * @idle: task in question
4609 * @cpu: cpu the idle task belongs to
4611 * NOTE: this function does not set the idle thread's NEED_RESCHED
4612 * flag, to make booting more robust.
4614 void init_idle(struct task_struct
*idle
, int cpu
)
4616 struct rq
*rq
= cpu_rq(cpu
);
4617 unsigned long flags
;
4619 raw_spin_lock_irqsave(&rq
->lock
, flags
);
4621 __sched_fork(0, idle
);
4622 idle
->state
= TASK_RUNNING
;
4623 idle
->se
.exec_start
= sched_clock();
4625 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
4627 * We're having a chicken and egg problem, even though we are
4628 * holding rq->lock, the cpu isn't yet set to this cpu so the
4629 * lockdep check in task_group() will fail.
4631 * Similar case to sched_fork(). / Alternatively we could
4632 * use task_rq_lock() here and obtain the other rq->lock.
4637 __set_task_cpu(idle
, cpu
);
4640 rq
->curr
= rq
->idle
= idle
;
4641 idle
->on_rq
= TASK_ON_RQ_QUEUED
;
4642 #if defined(CONFIG_SMP)
4645 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
4647 /* Set the preempt count _outside_ the spinlocks! */
4648 init_idle_preempt_count(idle
, cpu
);
4651 * The idle tasks have their own, simple scheduling class:
4653 idle
->sched_class
= &idle_sched_class
;
4654 ftrace_graph_init_idle_task(idle
, cpu
);
4655 vtime_init_idle(idle
, cpu
);
4656 #if defined(CONFIG_SMP)
4657 sprintf(idle
->comm
, "%s/%d", INIT_TASK_COMM
, cpu
);
4661 int cpuset_cpumask_can_shrink(const struct cpumask
*cur
,
4662 const struct cpumask
*trial
)
4664 int ret
= 1, trial_cpus
;
4665 struct dl_bw
*cur_dl_b
;
4666 unsigned long flags
;
4668 if (!cpumask_weight(cur
))
4671 rcu_read_lock_sched();
4672 cur_dl_b
= dl_bw_of(cpumask_any(cur
));
4673 trial_cpus
= cpumask_weight(trial
);
4675 raw_spin_lock_irqsave(&cur_dl_b
->lock
, flags
);
4676 if (cur_dl_b
->bw
!= -1 &&
4677 cur_dl_b
->bw
* trial_cpus
< cur_dl_b
->total_bw
)
4679 raw_spin_unlock_irqrestore(&cur_dl_b
->lock
, flags
);
4680 rcu_read_unlock_sched();
4685 int task_can_attach(struct task_struct
*p
,
4686 const struct cpumask
*cs_cpus_allowed
)
4691 * Kthreads which disallow setaffinity shouldn't be moved
4692 * to a new cpuset; we don't want to change their cpu
4693 * affinity and isolating such threads by their set of
4694 * allowed nodes is unnecessary. Thus, cpusets are not
4695 * applicable for such threads. This prevents checking for
4696 * success of set_cpus_allowed_ptr() on all attached tasks
4697 * before cpus_allowed may be changed.
4699 if (p
->flags
& PF_NO_SETAFFINITY
) {
4705 if (dl_task(p
) && !cpumask_intersects(task_rq(p
)->rd
->span
,
4707 unsigned int dest_cpu
= cpumask_any_and(cpu_active_mask
,
4712 unsigned long flags
;
4714 rcu_read_lock_sched();
4715 dl_b
= dl_bw_of(dest_cpu
);
4716 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
4717 cpus
= dl_bw_cpus(dest_cpu
);
4718 overflow
= __dl_overflow(dl_b
, cpus
, 0, p
->dl
.dl_bw
);
4723 * We reserve space for this task in the destination
4724 * root_domain, as we can't fail after this point.
4725 * We will free resources in the source root_domain
4726 * later on (see set_cpus_allowed_dl()).
4728 __dl_add(dl_b
, p
->dl
.dl_bw
);
4730 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
4731 rcu_read_unlock_sched();
4741 * move_queued_task - move a queued task to new rq.
4743 * Returns (locked) new rq. Old rq's lock is released.
4745 static struct rq
*move_queued_task(struct task_struct
*p
, int new_cpu
)
4747 struct rq
*rq
= task_rq(p
);
4749 lockdep_assert_held(&rq
->lock
);
4751 dequeue_task(rq
, p
, 0);
4752 p
->on_rq
= TASK_ON_RQ_MIGRATING
;
4753 set_task_cpu(p
, new_cpu
);
4754 raw_spin_unlock(&rq
->lock
);
4756 rq
= cpu_rq(new_cpu
);
4758 raw_spin_lock(&rq
->lock
);
4759 BUG_ON(task_cpu(p
) != new_cpu
);
4760 p
->on_rq
= TASK_ON_RQ_QUEUED
;
4761 enqueue_task(rq
, p
, 0);
4762 check_preempt_curr(rq
, p
, 0);
4767 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
4769 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
4770 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
4772 cpumask_copy(&p
->cpus_allowed
, new_mask
);
4773 p
->nr_cpus_allowed
= cpumask_weight(new_mask
);
4777 * This is how migration works:
4779 * 1) we invoke migration_cpu_stop() on the target CPU using
4781 * 2) stopper starts to run (implicitly forcing the migrated thread
4783 * 3) it checks whether the migrated task is still in the wrong runqueue.
4784 * 4) if it's in the wrong runqueue then the migration thread removes
4785 * it and puts it into the right queue.
4786 * 5) stopper completes and stop_one_cpu() returns and the migration
4791 * Change a given task's CPU affinity. Migrate the thread to a
4792 * proper CPU and schedule it away if the CPU it's executing on
4793 * is removed from the allowed bitmask.
4795 * NOTE: the caller must have a valid reference to the task, the
4796 * task must not exit() & deallocate itself prematurely. The
4797 * call is not atomic; no spinlocks may be held.
4799 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
4801 unsigned long flags
;
4803 unsigned int dest_cpu
;
4806 rq
= task_rq_lock(p
, &flags
);
4808 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
4811 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
4816 do_set_cpus_allowed(p
, new_mask
);
4818 /* Can the task run on the task's current CPU? If so, we're done */
4819 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
4822 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
4823 if (task_running(rq
, p
) || p
->state
== TASK_WAKING
) {
4824 struct migration_arg arg
= { p
, dest_cpu
};
4825 /* Need help from migration thread: drop lock and wait. */
4826 task_rq_unlock(rq
, p
, &flags
);
4827 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
4828 tlb_migrate_finish(p
->mm
);
4830 } else if (task_on_rq_queued(p
))
4831 rq
= move_queued_task(p
, dest_cpu
);
4833 task_rq_unlock(rq
, p
, &flags
);
4837 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
4840 * Move (not current) task off this cpu, onto dest cpu. We're doing
4841 * this because either it can't run here any more (set_cpus_allowed()
4842 * away from this CPU, or CPU going down), or because we're
4843 * attempting to rebalance this task on exec (sched_exec).
4845 * So we race with normal scheduler movements, but that's OK, as long
4846 * as the task is no longer on this CPU.
4848 * Returns non-zero if task was successfully migrated.
4850 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
4855 if (unlikely(!cpu_active(dest_cpu
)))
4858 rq
= cpu_rq(src_cpu
);
4860 raw_spin_lock(&p
->pi_lock
);
4861 raw_spin_lock(&rq
->lock
);
4862 /* Already moved. */
4863 if (task_cpu(p
) != src_cpu
)
4866 /* Affinity changed (again). */
4867 if (!cpumask_test_cpu(dest_cpu
, tsk_cpus_allowed(p
)))
4871 * If we're not on a rq, the next wake-up will ensure we're
4874 if (task_on_rq_queued(p
))
4875 rq
= move_queued_task(p
, dest_cpu
);
4879 raw_spin_unlock(&rq
->lock
);
4880 raw_spin_unlock(&p
->pi_lock
);
4884 #ifdef CONFIG_NUMA_BALANCING
4885 /* Migrate current task p to target_cpu */
4886 int migrate_task_to(struct task_struct
*p
, int target_cpu
)
4888 struct migration_arg arg
= { p
, target_cpu
};
4889 int curr_cpu
= task_cpu(p
);
4891 if (curr_cpu
== target_cpu
)
4894 if (!cpumask_test_cpu(target_cpu
, tsk_cpus_allowed(p
)))
4897 /* TODO: This is not properly updating schedstats */
4899 trace_sched_move_numa(p
, curr_cpu
, target_cpu
);
4900 return stop_one_cpu(curr_cpu
, migration_cpu_stop
, &arg
);
4904 * Requeue a task on a given node and accurately track the number of NUMA
4905 * tasks on the runqueues
4907 void sched_setnuma(struct task_struct
*p
, int nid
)
4910 unsigned long flags
;
4911 bool queued
, running
;
4913 rq
= task_rq_lock(p
, &flags
);
4914 queued
= task_on_rq_queued(p
);
4915 running
= task_current(rq
, p
);
4918 dequeue_task(rq
, p
, 0);
4920 put_prev_task(rq
, p
);
4922 p
->numa_preferred_nid
= nid
;
4925 p
->sched_class
->set_curr_task(rq
);
4927 enqueue_task(rq
, p
, 0);
4928 task_rq_unlock(rq
, p
, &flags
);
4933 * migration_cpu_stop - this will be executed by a highprio stopper thread
4934 * and performs thread migration by bumping thread off CPU then
4935 * 'pushing' onto another runqueue.
4937 static int migration_cpu_stop(void *data
)
4939 struct migration_arg
*arg
= data
;
4942 * The original target cpu might have gone down and we might
4943 * be on another cpu but it doesn't matter.
4945 local_irq_disable();
4947 * We need to explicitly wake pending tasks before running
4948 * __migrate_task() such that we will not miss enforcing cpus_allowed
4949 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
4951 sched_ttwu_pending();
4952 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
4957 #ifdef CONFIG_HOTPLUG_CPU
4960 * Ensures that the idle task is using init_mm right before its cpu goes
4963 void idle_task_exit(void)
4965 struct mm_struct
*mm
= current
->active_mm
;
4967 BUG_ON(cpu_online(smp_processor_id()));
4969 if (mm
!= &init_mm
) {
4970 switch_mm(mm
, &init_mm
, current
);
4971 finish_arch_post_lock_switch();
4977 * Since this CPU is going 'away' for a while, fold any nr_active delta
4978 * we might have. Assumes we're called after migrate_tasks() so that the
4979 * nr_active count is stable.
4981 * Also see the comment "Global load-average calculations".
4983 static void calc_load_migrate(struct rq
*rq
)
4985 long delta
= calc_load_fold_active(rq
);
4987 atomic_long_add(delta
, &calc_load_tasks
);
4990 static void put_prev_task_fake(struct rq
*rq
, struct task_struct
*prev
)
4994 static const struct sched_class fake_sched_class
= {
4995 .put_prev_task
= put_prev_task_fake
,
4998 static struct task_struct fake_task
= {
5000 * Avoid pull_{rt,dl}_task()
5002 .prio
= MAX_PRIO
+ 1,
5003 .sched_class
= &fake_sched_class
,
5007 * Migrate all tasks from the rq, sleeping tasks will be migrated by
5008 * try_to_wake_up()->select_task_rq().
5010 * Called with rq->lock held even though we'er in stop_machine() and
5011 * there's no concurrency possible, we hold the required locks anyway
5012 * because of lock validation efforts.
5014 static void migrate_tasks(unsigned int dead_cpu
)
5016 struct rq
*rq
= cpu_rq(dead_cpu
);
5017 struct task_struct
*next
, *stop
= rq
->stop
;
5021 * Fudge the rq selection such that the below task selection loop
5022 * doesn't get stuck on the currently eligible stop task.
5024 * We're currently inside stop_machine() and the rq is either stuck
5025 * in the stop_machine_cpu_stop() loop, or we're executing this code,
5026 * either way we should never end up calling schedule() until we're
5032 * put_prev_task() and pick_next_task() sched
5033 * class method both need to have an up-to-date
5034 * value of rq->clock[_task]
5036 update_rq_clock(rq
);
5040 * There's this thread running, bail when that's the only
5043 if (rq
->nr_running
== 1)
5046 next
= pick_next_task(rq
, &fake_task
);
5048 next
->sched_class
->put_prev_task(rq
, next
);
5050 /* Find suitable destination for @next, with force if needed. */
5051 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
5052 raw_spin_unlock(&rq
->lock
);
5054 __migrate_task(next
, dead_cpu
, dest_cpu
);
5056 raw_spin_lock(&rq
->lock
);
5062 #endif /* CONFIG_HOTPLUG_CPU */
5064 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5066 static struct ctl_table sd_ctl_dir
[] = {
5068 .procname
= "sched_domain",
5074 static struct ctl_table sd_ctl_root
[] = {
5076 .procname
= "kernel",
5078 .child
= sd_ctl_dir
,
5083 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5085 struct ctl_table
*entry
=
5086 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5091 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5093 struct ctl_table
*entry
;
5096 * In the intermediate directories, both the child directory and
5097 * procname are dynamically allocated and could fail but the mode
5098 * will always be set. In the lowest directory the names are
5099 * static strings and all have proc handlers.
5101 for (entry
= *tablep
; entry
->mode
; entry
++) {
5103 sd_free_ctl_entry(&entry
->child
);
5104 if (entry
->proc_handler
== NULL
)
5105 kfree(entry
->procname
);
5112 static int min_load_idx
= 0;
5113 static int max_load_idx
= CPU_LOAD_IDX_MAX
-1;
5116 set_table_entry(struct ctl_table
*entry
,
5117 const char *procname
, void *data
, int maxlen
,
5118 umode_t mode
, proc_handler
*proc_handler
,
5121 entry
->procname
= procname
;
5123 entry
->maxlen
= maxlen
;
5125 entry
->proc_handler
= proc_handler
;
5128 entry
->extra1
= &min_load_idx
;
5129 entry
->extra2
= &max_load_idx
;
5133 static struct ctl_table
*
5134 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5136 struct ctl_table
*table
= sd_alloc_ctl_entry(14);
5141 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5142 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5143 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5144 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5145 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5146 sizeof(int), 0644, proc_dointvec_minmax
, true);
5147 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5148 sizeof(int), 0644, proc_dointvec_minmax
, true);
5149 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5150 sizeof(int), 0644, proc_dointvec_minmax
, true);
5151 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5152 sizeof(int), 0644, proc_dointvec_minmax
, true);
5153 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5154 sizeof(int), 0644, proc_dointvec_minmax
, true);
5155 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5156 sizeof(int), 0644, proc_dointvec_minmax
, false);
5157 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5158 sizeof(int), 0644, proc_dointvec_minmax
, false);
5159 set_table_entry(&table
[9], "cache_nice_tries",
5160 &sd
->cache_nice_tries
,
5161 sizeof(int), 0644, proc_dointvec_minmax
, false);
5162 set_table_entry(&table
[10], "flags", &sd
->flags
,
5163 sizeof(int), 0644, proc_dointvec_minmax
, false);
5164 set_table_entry(&table
[11], "max_newidle_lb_cost",
5165 &sd
->max_newidle_lb_cost
,
5166 sizeof(long), 0644, proc_doulongvec_minmax
, false);
5167 set_table_entry(&table
[12], "name", sd
->name
,
5168 CORENAME_MAX_SIZE
, 0444, proc_dostring
, false);
5169 /* &table[13] is terminator */
5174 static struct ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5176 struct ctl_table
*entry
, *table
;
5177 struct sched_domain
*sd
;
5178 int domain_num
= 0, i
;
5181 for_each_domain(cpu
, sd
)
5183 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5188 for_each_domain(cpu
, sd
) {
5189 snprintf(buf
, 32, "domain%d", i
);
5190 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5192 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5199 static struct ctl_table_header
*sd_sysctl_header
;
5200 static void register_sched_domain_sysctl(void)
5202 int i
, cpu_num
= num_possible_cpus();
5203 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5206 WARN_ON(sd_ctl_dir
[0].child
);
5207 sd_ctl_dir
[0].child
= entry
;
5212 for_each_possible_cpu(i
) {
5213 snprintf(buf
, 32, "cpu%d", i
);
5214 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5216 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5220 WARN_ON(sd_sysctl_header
);
5221 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5224 /* may be called multiple times per register */
5225 static void unregister_sched_domain_sysctl(void)
5227 if (sd_sysctl_header
)
5228 unregister_sysctl_table(sd_sysctl_header
);
5229 sd_sysctl_header
= NULL
;
5230 if (sd_ctl_dir
[0].child
)
5231 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5234 static void register_sched_domain_sysctl(void)
5237 static void unregister_sched_domain_sysctl(void)
5242 static void set_rq_online(struct rq
*rq
)
5245 const struct sched_class
*class;
5247 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5250 for_each_class(class) {
5251 if (class->rq_online
)
5252 class->rq_online(rq
);
5257 static void set_rq_offline(struct rq
*rq
)
5260 const struct sched_class
*class;
5262 for_each_class(class) {
5263 if (class->rq_offline
)
5264 class->rq_offline(rq
);
5267 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5273 * migration_call - callback that gets triggered when a CPU is added.
5274 * Here we can start up the necessary migration thread for the new CPU.
5277 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5279 int cpu
= (long)hcpu
;
5280 unsigned long flags
;
5281 struct rq
*rq
= cpu_rq(cpu
);
5283 switch (action
& ~CPU_TASKS_FROZEN
) {
5285 case CPU_UP_PREPARE
:
5286 rq
->calc_load_update
= calc_load_update
;
5290 /* Update our root-domain */
5291 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5293 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5297 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5300 #ifdef CONFIG_HOTPLUG_CPU
5302 sched_ttwu_pending();
5303 /* Update our root-domain */
5304 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5306 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5310 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
5311 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5315 calc_load_migrate(rq
);
5320 update_max_interval();
5326 * Register at high priority so that task migration (migrate_all_tasks)
5327 * happens before everything else. This has to be lower priority than
5328 * the notifier in the perf_event subsystem, though.
5330 static struct notifier_block migration_notifier
= {
5331 .notifier_call
= migration_call
,
5332 .priority
= CPU_PRI_MIGRATION
,
5335 static void __cpuinit
set_cpu_rq_start_time(void)
5337 int cpu
= smp_processor_id();
5338 struct rq
*rq
= cpu_rq(cpu
);
5339 rq
->age_stamp
= sched_clock_cpu(cpu
);
5342 static int sched_cpu_active(struct notifier_block
*nfb
,
5343 unsigned long action
, void *hcpu
)
5345 switch (action
& ~CPU_TASKS_FROZEN
) {
5347 set_cpu_rq_start_time();
5349 case CPU_DOWN_FAILED
:
5350 set_cpu_active((long)hcpu
, true);
5357 static int sched_cpu_inactive(struct notifier_block
*nfb
,
5358 unsigned long action
, void *hcpu
)
5360 unsigned long flags
;
5361 long cpu
= (long)hcpu
;
5364 switch (action
& ~CPU_TASKS_FROZEN
) {
5365 case CPU_DOWN_PREPARE
:
5366 set_cpu_active(cpu
, false);
5368 /* explicitly allow suspend */
5369 if (!(action
& CPU_TASKS_FROZEN
)) {
5373 rcu_read_lock_sched();
5374 dl_b
= dl_bw_of(cpu
);
5376 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
5377 cpus
= dl_bw_cpus(cpu
);
5378 overflow
= __dl_overflow(dl_b
, cpus
, 0, 0);
5379 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
5381 rcu_read_unlock_sched();
5384 return notifier_from_errno(-EBUSY
);
5392 static int __init
migration_init(void)
5394 void *cpu
= (void *)(long)smp_processor_id();
5397 /* Initialize migration for the boot CPU */
5398 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5399 BUG_ON(err
== NOTIFY_BAD
);
5400 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5401 register_cpu_notifier(&migration_notifier
);
5403 /* Register cpu active notifiers */
5404 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
5405 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
5409 early_initcall(migration_init
);
5414 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
5416 #ifdef CONFIG_SCHED_DEBUG
5418 static __read_mostly
int sched_debug_enabled
;
5420 static int __init
sched_debug_setup(char *str
)
5422 sched_debug_enabled
= 1;
5426 early_param("sched_debug", sched_debug_setup
);
5428 static inline bool sched_debug(void)
5430 return sched_debug_enabled
;
5433 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5434 struct cpumask
*groupmask
)
5436 struct sched_group
*group
= sd
->groups
;
5439 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5440 cpumask_clear(groupmask
);
5442 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5444 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5445 printk("does not load-balance\n");
5447 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5452 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5454 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5455 printk(KERN_ERR
"ERROR: domain->span does not contain "
5458 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
5459 printk(KERN_ERR
"ERROR: domain->groups does not contain"
5463 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
5467 printk(KERN_ERR
"ERROR: group is NULL\n");
5472 * Even though we initialize ->capacity to something semi-sane,
5473 * we leave capacity_orig unset. This allows us to detect if
5474 * domain iteration is still funny without causing /0 traps.
5476 if (!group
->sgc
->capacity_orig
) {
5477 printk(KERN_CONT
"\n");
5478 printk(KERN_ERR
"ERROR: domain->cpu_capacity not set\n");
5482 if (!cpumask_weight(sched_group_cpus(group
))) {
5483 printk(KERN_CONT
"\n");
5484 printk(KERN_ERR
"ERROR: empty group\n");
5488 if (!(sd
->flags
& SD_OVERLAP
) &&
5489 cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
5490 printk(KERN_CONT
"\n");
5491 printk(KERN_ERR
"ERROR: repeated CPUs\n");
5495 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
5497 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
5499 printk(KERN_CONT
" %s", str
);
5500 if (group
->sgc
->capacity
!= SCHED_CAPACITY_SCALE
) {
5501 printk(KERN_CONT
" (cpu_capacity = %d)",
5502 group
->sgc
->capacity
);
5505 group
= group
->next
;
5506 } while (group
!= sd
->groups
);
5507 printk(KERN_CONT
"\n");
5509 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
5510 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
5513 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
5514 printk(KERN_ERR
"ERROR: parent span is not a superset "
5515 "of domain->span\n");
5519 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
5523 if (!sched_debug_enabled
)
5527 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
5531 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
5534 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
5542 #else /* !CONFIG_SCHED_DEBUG */
5543 # define sched_domain_debug(sd, cpu) do { } while (0)
5544 static inline bool sched_debug(void)
5548 #endif /* CONFIG_SCHED_DEBUG */
5550 static int sd_degenerate(struct sched_domain
*sd
)
5552 if (cpumask_weight(sched_domain_span(sd
)) == 1)
5555 /* Following flags need at least 2 groups */
5556 if (sd
->flags
& (SD_LOAD_BALANCE
|
5557 SD_BALANCE_NEWIDLE
|
5560 SD_SHARE_CPUCAPACITY
|
5561 SD_SHARE_PKG_RESOURCES
|
5562 SD_SHARE_POWERDOMAIN
)) {
5563 if (sd
->groups
!= sd
->groups
->next
)
5567 /* Following flags don't use groups */
5568 if (sd
->flags
& (SD_WAKE_AFFINE
))
5575 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
5577 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
5579 if (sd_degenerate(parent
))
5582 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
5585 /* Flags needing groups don't count if only 1 group in parent */
5586 if (parent
->groups
== parent
->groups
->next
) {
5587 pflags
&= ~(SD_LOAD_BALANCE
|
5588 SD_BALANCE_NEWIDLE
|
5591 SD_SHARE_CPUCAPACITY
|
5592 SD_SHARE_PKG_RESOURCES
|
5594 SD_SHARE_POWERDOMAIN
);
5595 if (nr_node_ids
== 1)
5596 pflags
&= ~SD_SERIALIZE
;
5598 if (~cflags
& pflags
)
5604 static void free_rootdomain(struct rcu_head
*rcu
)
5606 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
5608 cpupri_cleanup(&rd
->cpupri
);
5609 cpudl_cleanup(&rd
->cpudl
);
5610 free_cpumask_var(rd
->dlo_mask
);
5611 free_cpumask_var(rd
->rto_mask
);
5612 free_cpumask_var(rd
->online
);
5613 free_cpumask_var(rd
->span
);
5617 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
5619 struct root_domain
*old_rd
= NULL
;
5620 unsigned long flags
;
5622 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5627 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
5630 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
5633 * If we dont want to free the old_rd yet then
5634 * set old_rd to NULL to skip the freeing later
5637 if (!atomic_dec_and_test(&old_rd
->refcount
))
5641 atomic_inc(&rd
->refcount
);
5644 cpumask_set_cpu(rq
->cpu
, rd
->span
);
5645 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
5648 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5651 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
5654 static int init_rootdomain(struct root_domain
*rd
)
5656 memset(rd
, 0, sizeof(*rd
));
5658 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
5660 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
5662 if (!alloc_cpumask_var(&rd
->dlo_mask
, GFP_KERNEL
))
5664 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
5667 init_dl_bw(&rd
->dl_bw
);
5668 if (cpudl_init(&rd
->cpudl
) != 0)
5671 if (cpupri_init(&rd
->cpupri
) != 0)
5676 free_cpumask_var(rd
->rto_mask
);
5678 free_cpumask_var(rd
->dlo_mask
);
5680 free_cpumask_var(rd
->online
);
5682 free_cpumask_var(rd
->span
);
5688 * By default the system creates a single root-domain with all cpus as
5689 * members (mimicking the global state we have today).
5691 struct root_domain def_root_domain
;
5693 static void init_defrootdomain(void)
5695 init_rootdomain(&def_root_domain
);
5697 atomic_set(&def_root_domain
.refcount
, 1);
5700 static struct root_domain
*alloc_rootdomain(void)
5702 struct root_domain
*rd
;
5704 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
5708 if (init_rootdomain(rd
) != 0) {
5716 static void free_sched_groups(struct sched_group
*sg
, int free_sgc
)
5718 struct sched_group
*tmp
, *first
;
5727 if (free_sgc
&& atomic_dec_and_test(&sg
->sgc
->ref
))
5732 } while (sg
!= first
);
5735 static void free_sched_domain(struct rcu_head
*rcu
)
5737 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
5740 * If its an overlapping domain it has private groups, iterate and
5743 if (sd
->flags
& SD_OVERLAP
) {
5744 free_sched_groups(sd
->groups
, 1);
5745 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
5746 kfree(sd
->groups
->sgc
);
5752 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
5754 call_rcu(&sd
->rcu
, free_sched_domain
);
5757 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
5759 for (; sd
; sd
= sd
->parent
)
5760 destroy_sched_domain(sd
, cpu
);
5764 * Keep a special pointer to the highest sched_domain that has
5765 * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
5766 * allows us to avoid some pointer chasing select_idle_sibling().
5768 * Also keep a unique ID per domain (we use the first cpu number in
5769 * the cpumask of the domain), this allows us to quickly tell if
5770 * two cpus are in the same cache domain, see cpus_share_cache().
5772 DEFINE_PER_CPU(struct sched_domain
*, sd_llc
);
5773 DEFINE_PER_CPU(int, sd_llc_size
);
5774 DEFINE_PER_CPU(int, sd_llc_id
);
5775 DEFINE_PER_CPU(struct sched_domain
*, sd_numa
);
5776 DEFINE_PER_CPU(struct sched_domain
*, sd_busy
);
5777 DEFINE_PER_CPU(struct sched_domain
*, sd_asym
);
5779 static void update_top_cache_domain(int cpu
)
5781 struct sched_domain
*sd
;
5782 struct sched_domain
*busy_sd
= NULL
;
5786 sd
= highest_flag_domain(cpu
, SD_SHARE_PKG_RESOURCES
);
5788 id
= cpumask_first(sched_domain_span(sd
));
5789 size
= cpumask_weight(sched_domain_span(sd
));
5790 busy_sd
= sd
->parent
; /* sd_busy */
5792 rcu_assign_pointer(per_cpu(sd_busy
, cpu
), busy_sd
);
5794 rcu_assign_pointer(per_cpu(sd_llc
, cpu
), sd
);
5795 per_cpu(sd_llc_size
, cpu
) = size
;
5796 per_cpu(sd_llc_id
, cpu
) = id
;
5798 sd
= lowest_flag_domain(cpu
, SD_NUMA
);
5799 rcu_assign_pointer(per_cpu(sd_numa
, cpu
), sd
);
5801 sd
= highest_flag_domain(cpu
, SD_ASYM_PACKING
);
5802 rcu_assign_pointer(per_cpu(sd_asym
, cpu
), sd
);
5806 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5807 * hold the hotplug lock.
5810 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
5812 struct rq
*rq
= cpu_rq(cpu
);
5813 struct sched_domain
*tmp
;
5815 /* Remove the sched domains which do not contribute to scheduling. */
5816 for (tmp
= sd
; tmp
; ) {
5817 struct sched_domain
*parent
= tmp
->parent
;
5821 if (sd_parent_degenerate(tmp
, parent
)) {
5822 tmp
->parent
= parent
->parent
;
5824 parent
->parent
->child
= tmp
;
5826 * Transfer SD_PREFER_SIBLING down in case of a
5827 * degenerate parent; the spans match for this
5828 * so the property transfers.
5830 if (parent
->flags
& SD_PREFER_SIBLING
)
5831 tmp
->flags
|= SD_PREFER_SIBLING
;
5832 destroy_sched_domain(parent
, cpu
);
5837 if (sd
&& sd_degenerate(sd
)) {
5840 destroy_sched_domain(tmp
, cpu
);
5845 sched_domain_debug(sd
, cpu
);
5847 rq_attach_root(rq
, rd
);
5849 rcu_assign_pointer(rq
->sd
, sd
);
5850 destroy_sched_domains(tmp
, cpu
);
5852 update_top_cache_domain(cpu
);
5855 /* cpus with isolated domains */
5856 static cpumask_var_t cpu_isolated_map
;
5858 /* Setup the mask of cpus configured for isolated domains */
5859 static int __init
isolated_cpu_setup(char *str
)
5861 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
5862 cpulist_parse(str
, cpu_isolated_map
);
5866 __setup("isolcpus=", isolated_cpu_setup
);
5869 struct sched_domain
** __percpu sd
;
5870 struct root_domain
*rd
;
5881 * Build an iteration mask that can exclude certain CPUs from the upwards
5884 * Asymmetric node setups can result in situations where the domain tree is of
5885 * unequal depth, make sure to skip domains that already cover the entire
5888 * In that case build_sched_domains() will have terminated the iteration early
5889 * and our sibling sd spans will be empty. Domains should always include the
5890 * cpu they're built on, so check that.
5893 static void build_group_mask(struct sched_domain
*sd
, struct sched_group
*sg
)
5895 const struct cpumask
*span
= sched_domain_span(sd
);
5896 struct sd_data
*sdd
= sd
->private;
5897 struct sched_domain
*sibling
;
5900 for_each_cpu(i
, span
) {
5901 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5902 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5905 cpumask_set_cpu(i
, sched_group_mask(sg
));
5910 * Return the canonical balance cpu for this group, this is the first cpu
5911 * of this group that's also in the iteration mask.
5913 int group_balance_cpu(struct sched_group
*sg
)
5915 return cpumask_first_and(sched_group_cpus(sg
), sched_group_mask(sg
));
5919 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
5921 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
5922 const struct cpumask
*span
= sched_domain_span(sd
);
5923 struct cpumask
*covered
= sched_domains_tmpmask
;
5924 struct sd_data
*sdd
= sd
->private;
5925 struct sched_domain
*sibling
;
5928 cpumask_clear(covered
);
5930 for_each_cpu(i
, span
) {
5931 struct cpumask
*sg_span
;
5933 if (cpumask_test_cpu(i
, covered
))
5936 sibling
= *per_cpu_ptr(sdd
->sd
, i
);
5938 /* See the comment near build_group_mask(). */
5939 if (!cpumask_test_cpu(i
, sched_domain_span(sibling
)))
5942 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
5943 GFP_KERNEL
, cpu_to_node(cpu
));
5948 sg_span
= sched_group_cpus(sg
);
5950 cpumask_copy(sg_span
, sched_domain_span(sibling
->child
));
5952 cpumask_set_cpu(i
, sg_span
);
5954 cpumask_or(covered
, covered
, sg_span
);
5956 sg
->sgc
= *per_cpu_ptr(sdd
->sgc
, i
);
5957 if (atomic_inc_return(&sg
->sgc
->ref
) == 1)
5958 build_group_mask(sd
, sg
);
5961 * Initialize sgc->capacity such that even if we mess up the
5962 * domains and no possible iteration will get us here, we won't
5965 sg
->sgc
->capacity
= SCHED_CAPACITY_SCALE
* cpumask_weight(sg_span
);
5966 sg
->sgc
->capacity_orig
= sg
->sgc
->capacity
;
5969 * Make sure the first group of this domain contains the
5970 * canonical balance cpu. Otherwise the sched_domain iteration
5971 * breaks. See update_sg_lb_stats().
5973 if ((!groups
&& cpumask_test_cpu(cpu
, sg_span
)) ||
5974 group_balance_cpu(sg
) == cpu
)
5984 sd
->groups
= groups
;
5989 free_sched_groups(first
, 0);
5994 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
5996 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
5997 struct sched_domain
*child
= sd
->child
;
6000 cpu
= cpumask_first(sched_domain_span(child
));
6003 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
6004 (*sg
)->sgc
= *per_cpu_ptr(sdd
->sgc
, cpu
);
6005 atomic_set(&(*sg
)->sgc
->ref
, 1); /* for claim_allocations */
6012 * build_sched_groups will build a circular linked list of the groups
6013 * covered by the given span, and will set each group's ->cpumask correctly,
6014 * and ->cpu_capacity to 0.
6016 * Assumes the sched_domain tree is fully constructed
6019 build_sched_groups(struct sched_domain
*sd
, int cpu
)
6021 struct sched_group
*first
= NULL
, *last
= NULL
;
6022 struct sd_data
*sdd
= sd
->private;
6023 const struct cpumask
*span
= sched_domain_span(sd
);
6024 struct cpumask
*covered
;
6027 get_group(cpu
, sdd
, &sd
->groups
);
6028 atomic_inc(&sd
->groups
->ref
);
6030 if (cpu
!= cpumask_first(span
))
6033 lockdep_assert_held(&sched_domains_mutex
);
6034 covered
= sched_domains_tmpmask
;
6036 cpumask_clear(covered
);
6038 for_each_cpu(i
, span
) {
6039 struct sched_group
*sg
;
6042 if (cpumask_test_cpu(i
, covered
))
6045 group
= get_group(i
, sdd
, &sg
);
6046 cpumask_setall(sched_group_mask(sg
));
6048 for_each_cpu(j
, span
) {
6049 if (get_group(j
, sdd
, NULL
) != group
)
6052 cpumask_set_cpu(j
, covered
);
6053 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6068 * Initialize sched groups cpu_capacity.
6070 * cpu_capacity indicates the capacity of sched group, which is used while
6071 * distributing the load between different sched groups in a sched domain.
6072 * Typically cpu_capacity for all the groups in a sched domain will be same
6073 * unless there are asymmetries in the topology. If there are asymmetries,
6074 * group having more cpu_capacity will pickup more load compared to the
6075 * group having less cpu_capacity.
6077 static void init_sched_groups_capacity(int cpu
, struct sched_domain
*sd
)
6079 struct sched_group
*sg
= sd
->groups
;
6084 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
6086 } while (sg
!= sd
->groups
);
6088 if (cpu
!= group_balance_cpu(sg
))
6091 update_group_capacity(sd
, cpu
);
6092 atomic_set(&sg
->sgc
->nr_busy_cpus
, sg
->group_weight
);
6096 * Initializers for schedule domains
6097 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6100 static int default_relax_domain_level
= -1;
6101 int sched_domain_level_max
;
6103 static int __init
setup_relax_domain_level(char *str
)
6105 if (kstrtoint(str
, 0, &default_relax_domain_level
))
6106 pr_warn("Unable to set relax_domain_level\n");
6110 __setup("relax_domain_level=", setup_relax_domain_level
);
6112 static void set_domain_attribute(struct sched_domain
*sd
,
6113 struct sched_domain_attr
*attr
)
6117 if (!attr
|| attr
->relax_domain_level
< 0) {
6118 if (default_relax_domain_level
< 0)
6121 request
= default_relax_domain_level
;
6123 request
= attr
->relax_domain_level
;
6124 if (request
< sd
->level
) {
6125 /* turn off idle balance on this domain */
6126 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6128 /* turn on idle balance on this domain */
6129 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6133 static void __sdt_free(const struct cpumask
*cpu_map
);
6134 static int __sdt_alloc(const struct cpumask
*cpu_map
);
6136 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6137 const struct cpumask
*cpu_map
)
6141 if (!atomic_read(&d
->rd
->refcount
))
6142 free_rootdomain(&d
->rd
->rcu
); /* fall through */
6144 free_percpu(d
->sd
); /* fall through */
6146 __sdt_free(cpu_map
); /* fall through */
6152 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6153 const struct cpumask
*cpu_map
)
6155 memset(d
, 0, sizeof(*d
));
6157 if (__sdt_alloc(cpu_map
))
6158 return sa_sd_storage
;
6159 d
->sd
= alloc_percpu(struct sched_domain
*);
6161 return sa_sd_storage
;
6162 d
->rd
= alloc_rootdomain();
6165 return sa_rootdomain
;
6169 * NULL the sd_data elements we've used to build the sched_domain and
6170 * sched_group structure so that the subsequent __free_domain_allocs()
6171 * will not free the data we're using.
6173 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
6175 struct sd_data
*sdd
= sd
->private;
6177 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
6178 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
6180 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
6181 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
6183 if (atomic_read(&(*per_cpu_ptr(sdd
->sgc
, cpu
))->ref
))
6184 *per_cpu_ptr(sdd
->sgc
, cpu
) = NULL
;
6188 static int sched_domains_numa_levels
;
6189 enum numa_topology_type sched_numa_topology_type
;
6190 static int *sched_domains_numa_distance
;
6191 int sched_max_numa_distance
;
6192 static struct cpumask
***sched_domains_numa_masks
;
6193 static int sched_domains_curr_level
;
6197 * SD_flags allowed in topology descriptions.
6199 * SD_SHARE_CPUCAPACITY - describes SMT topologies
6200 * SD_SHARE_PKG_RESOURCES - describes shared caches
6201 * SD_NUMA - describes NUMA topologies
6202 * SD_SHARE_POWERDOMAIN - describes shared power domain
6205 * SD_ASYM_PACKING - describes SMT quirks
6207 #define TOPOLOGY_SD_FLAGS \
6208 (SD_SHARE_CPUCAPACITY | \
6209 SD_SHARE_PKG_RESOURCES | \
6212 SD_SHARE_POWERDOMAIN)
6214 static struct sched_domain
*
6215 sd_init(struct sched_domain_topology_level
*tl
, int cpu
)
6217 struct sched_domain
*sd
= *per_cpu_ptr(tl
->data
.sd
, cpu
);
6218 int sd_weight
, sd_flags
= 0;
6222 * Ugly hack to pass state to sd_numa_mask()...
6224 sched_domains_curr_level
= tl
->numa_level
;
6227 sd_weight
= cpumask_weight(tl
->mask(cpu
));
6230 sd_flags
= (*tl
->sd_flags
)();
6231 if (WARN_ONCE(sd_flags
& ~TOPOLOGY_SD_FLAGS
,
6232 "wrong sd_flags in topology description\n"))
6233 sd_flags
&= ~TOPOLOGY_SD_FLAGS
;
6235 *sd
= (struct sched_domain
){
6236 .min_interval
= sd_weight
,
6237 .max_interval
= 2*sd_weight
,
6239 .imbalance_pct
= 125,
6241 .cache_nice_tries
= 0,
6248 .flags
= 1*SD_LOAD_BALANCE
6249 | 1*SD_BALANCE_NEWIDLE
6254 | 0*SD_SHARE_CPUCAPACITY
6255 | 0*SD_SHARE_PKG_RESOURCES
6257 | 0*SD_PREFER_SIBLING
6262 .last_balance
= jiffies
,
6263 .balance_interval
= sd_weight
,
6265 .max_newidle_lb_cost
= 0,
6266 .next_decay_max_lb_cost
= jiffies
,
6267 #ifdef CONFIG_SCHED_DEBUG
6273 * Convert topological properties into behaviour.
6276 if (sd
->flags
& SD_SHARE_CPUCAPACITY
) {
6277 sd
->imbalance_pct
= 110;
6278 sd
->smt_gain
= 1178; /* ~15% */
6280 } else if (sd
->flags
& SD_SHARE_PKG_RESOURCES
) {
6281 sd
->imbalance_pct
= 117;
6282 sd
->cache_nice_tries
= 1;
6286 } else if (sd
->flags
& SD_NUMA
) {
6287 sd
->cache_nice_tries
= 2;
6291 sd
->flags
|= SD_SERIALIZE
;
6292 if (sched_domains_numa_distance
[tl
->numa_level
] > RECLAIM_DISTANCE
) {
6293 sd
->flags
&= ~(SD_BALANCE_EXEC
|
6300 sd
->flags
|= SD_PREFER_SIBLING
;
6301 sd
->cache_nice_tries
= 1;
6306 sd
->private = &tl
->data
;
6312 * Topology list, bottom-up.
6314 static struct sched_domain_topology_level default_topology
[] = {
6315 #ifdef CONFIG_SCHED_SMT
6316 { cpu_smt_mask
, cpu_smt_flags
, SD_INIT_NAME(SMT
) },
6318 #ifdef CONFIG_SCHED_MC
6319 { cpu_coregroup_mask
, cpu_core_flags
, SD_INIT_NAME(MC
) },
6321 { cpu_cpu_mask
, SD_INIT_NAME(DIE
) },
6325 struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
6327 #define for_each_sd_topology(tl) \
6328 for (tl = sched_domain_topology; tl->mask; tl++)
6330 void set_sched_topology(struct sched_domain_topology_level
*tl
)
6332 sched_domain_topology
= tl
;
6337 static const struct cpumask
*sd_numa_mask(int cpu
)
6339 return sched_domains_numa_masks
[sched_domains_curr_level
][cpu_to_node(cpu
)];
6342 static void sched_numa_warn(const char *str
)
6344 static int done
= false;
6352 printk(KERN_WARNING
"ERROR: %s\n\n", str
);
6354 for (i
= 0; i
< nr_node_ids
; i
++) {
6355 printk(KERN_WARNING
" ");
6356 for (j
= 0; j
< nr_node_ids
; j
++)
6357 printk(KERN_CONT
"%02d ", node_distance(i
,j
));
6358 printk(KERN_CONT
"\n");
6360 printk(KERN_WARNING
"\n");
6363 bool find_numa_distance(int distance
)
6367 if (distance
== node_distance(0, 0))
6370 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6371 if (sched_domains_numa_distance
[i
] == distance
)
6379 * A system can have three types of NUMA topology:
6380 * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system
6381 * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes
6382 * NUMA_BACKPLANE: nodes can reach other nodes through a backplane
6384 * The difference between a glueless mesh topology and a backplane
6385 * topology lies in whether communication between not directly
6386 * connected nodes goes through intermediary nodes (where programs
6387 * could run), or through backplane controllers. This affects
6388 * placement of programs.
6390 * The type of topology can be discerned with the following tests:
6391 * - If the maximum distance between any nodes is 1 hop, the system
6392 * is directly connected.
6393 * - If for two nodes A and B, located N > 1 hops away from each other,
6394 * there is an intermediary node C, which is < N hops away from both
6395 * nodes A and B, the system is a glueless mesh.
6397 static void init_numa_topology_type(void)
6401 n
= sched_max_numa_distance
;
6404 sched_numa_topology_type
= NUMA_DIRECT
;
6406 for_each_online_node(a
) {
6407 for_each_online_node(b
) {
6408 /* Find two nodes furthest removed from each other. */
6409 if (node_distance(a
, b
) < n
)
6412 /* Is there an intermediary node between a and b? */
6413 for_each_online_node(c
) {
6414 if (node_distance(a
, c
) < n
&&
6415 node_distance(b
, c
) < n
) {
6416 sched_numa_topology_type
=
6422 sched_numa_topology_type
= NUMA_BACKPLANE
;
6428 static void sched_init_numa(void)
6430 int next_distance
, curr_distance
= node_distance(0, 0);
6431 struct sched_domain_topology_level
*tl
;
6435 sched_domains_numa_distance
= kzalloc(sizeof(int) * nr_node_ids
, GFP_KERNEL
);
6436 if (!sched_domains_numa_distance
)
6440 * O(nr_nodes^2) deduplicating selection sort -- in order to find the
6441 * unique distances in the node_distance() table.
6443 * Assumes node_distance(0,j) includes all distances in
6444 * node_distance(i,j) in order to avoid cubic time.
6446 next_distance
= curr_distance
;
6447 for (i
= 0; i
< nr_node_ids
; i
++) {
6448 for (j
= 0; j
< nr_node_ids
; j
++) {
6449 for (k
= 0; k
< nr_node_ids
; k
++) {
6450 int distance
= node_distance(i
, k
);
6452 if (distance
> curr_distance
&&
6453 (distance
< next_distance
||
6454 next_distance
== curr_distance
))
6455 next_distance
= distance
;
6458 * While not a strong assumption it would be nice to know
6459 * about cases where if node A is connected to B, B is not
6460 * equally connected to A.
6462 if (sched_debug() && node_distance(k
, i
) != distance
)
6463 sched_numa_warn("Node-distance not symmetric");
6465 if (sched_debug() && i
&& !find_numa_distance(distance
))
6466 sched_numa_warn("Node-0 not representative");
6468 if (next_distance
!= curr_distance
) {
6469 sched_domains_numa_distance
[level
++] = next_distance
;
6470 sched_domains_numa_levels
= level
;
6471 curr_distance
= next_distance
;
6476 * In case of sched_debug() we verify the above assumption.
6486 * 'level' contains the number of unique distances, excluding the
6487 * identity distance node_distance(i,i).
6489 * The sched_domains_numa_distance[] array includes the actual distance
6494 * Here, we should temporarily reset sched_domains_numa_levels to 0.
6495 * If it fails to allocate memory for array sched_domains_numa_masks[][],
6496 * the array will contain less then 'level' members. This could be
6497 * dangerous when we use it to iterate array sched_domains_numa_masks[][]
6498 * in other functions.
6500 * We reset it to 'level' at the end of this function.
6502 sched_domains_numa_levels
= 0;
6504 sched_domains_numa_masks
= kzalloc(sizeof(void *) * level
, GFP_KERNEL
);
6505 if (!sched_domains_numa_masks
)
6509 * Now for each level, construct a mask per node which contains all
6510 * cpus of nodes that are that many hops away from us.
6512 for (i
= 0; i
< level
; i
++) {
6513 sched_domains_numa_masks
[i
] =
6514 kzalloc(nr_node_ids
* sizeof(void *), GFP_KERNEL
);
6515 if (!sched_domains_numa_masks
[i
])
6518 for (j
= 0; j
< nr_node_ids
; j
++) {
6519 struct cpumask
*mask
= kzalloc(cpumask_size(), GFP_KERNEL
);
6523 sched_domains_numa_masks
[i
][j
] = mask
;
6525 for (k
= 0; k
< nr_node_ids
; k
++) {
6526 if (node_distance(j
, k
) > sched_domains_numa_distance
[i
])
6529 cpumask_or(mask
, mask
, cpumask_of_node(k
));
6534 /* Compute default topology size */
6535 for (i
= 0; sched_domain_topology
[i
].mask
; i
++);
6537 tl
= kzalloc((i
+ level
+ 1) *
6538 sizeof(struct sched_domain_topology_level
), GFP_KERNEL
);
6543 * Copy the default topology bits..
6545 for (i
= 0; sched_domain_topology
[i
].mask
; i
++)
6546 tl
[i
] = sched_domain_topology
[i
];
6549 * .. and append 'j' levels of NUMA goodness.
6551 for (j
= 0; j
< level
; i
++, j
++) {
6552 tl
[i
] = (struct sched_domain_topology_level
){
6553 .mask
= sd_numa_mask
,
6554 .sd_flags
= cpu_numa_flags
,
6555 .flags
= SDTL_OVERLAP
,
6561 sched_domain_topology
= tl
;
6563 sched_domains_numa_levels
= level
;
6564 sched_max_numa_distance
= sched_domains_numa_distance
[level
- 1];
6566 init_numa_topology_type();
6569 static void sched_domains_numa_masks_set(int cpu
)
6572 int node
= cpu_to_node(cpu
);
6574 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6575 for (j
= 0; j
< nr_node_ids
; j
++) {
6576 if (node_distance(j
, node
) <= sched_domains_numa_distance
[i
])
6577 cpumask_set_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6582 static void sched_domains_numa_masks_clear(int cpu
)
6585 for (i
= 0; i
< sched_domains_numa_levels
; i
++) {
6586 for (j
= 0; j
< nr_node_ids
; j
++)
6587 cpumask_clear_cpu(cpu
, sched_domains_numa_masks
[i
][j
]);
6592 * Update sched_domains_numa_masks[level][node] array when new cpus
6595 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6596 unsigned long action
,
6599 int cpu
= (long)hcpu
;
6601 switch (action
& ~CPU_TASKS_FROZEN
) {
6603 sched_domains_numa_masks_set(cpu
);
6607 sched_domains_numa_masks_clear(cpu
);
6617 static inline void sched_init_numa(void)
6621 static int sched_domains_numa_masks_update(struct notifier_block
*nfb
,
6622 unsigned long action
,
6627 #endif /* CONFIG_NUMA */
6629 static int __sdt_alloc(const struct cpumask
*cpu_map
)
6631 struct sched_domain_topology_level
*tl
;
6634 for_each_sd_topology(tl
) {
6635 struct sd_data
*sdd
= &tl
->data
;
6637 sdd
->sd
= alloc_percpu(struct sched_domain
*);
6641 sdd
->sg
= alloc_percpu(struct sched_group
*);
6645 sdd
->sgc
= alloc_percpu(struct sched_group_capacity
*);
6649 for_each_cpu(j
, cpu_map
) {
6650 struct sched_domain
*sd
;
6651 struct sched_group
*sg
;
6652 struct sched_group_capacity
*sgc
;
6654 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
6655 GFP_KERNEL
, cpu_to_node(j
));
6659 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
6661 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6662 GFP_KERNEL
, cpu_to_node(j
));
6668 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
6670 sgc
= kzalloc_node(sizeof(struct sched_group_capacity
) + cpumask_size(),
6671 GFP_KERNEL
, cpu_to_node(j
));
6675 *per_cpu_ptr(sdd
->sgc
, j
) = sgc
;
6682 static void __sdt_free(const struct cpumask
*cpu_map
)
6684 struct sched_domain_topology_level
*tl
;
6687 for_each_sd_topology(tl
) {
6688 struct sd_data
*sdd
= &tl
->data
;
6690 for_each_cpu(j
, cpu_map
) {
6691 struct sched_domain
*sd
;
6694 sd
= *per_cpu_ptr(sdd
->sd
, j
);
6695 if (sd
&& (sd
->flags
& SD_OVERLAP
))
6696 free_sched_groups(sd
->groups
, 0);
6697 kfree(*per_cpu_ptr(sdd
->sd
, j
));
6701 kfree(*per_cpu_ptr(sdd
->sg
, j
));
6703 kfree(*per_cpu_ptr(sdd
->sgc
, j
));
6705 free_percpu(sdd
->sd
);
6707 free_percpu(sdd
->sg
);
6709 free_percpu(sdd
->sgc
);
6714 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
6715 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6716 struct sched_domain
*child
, int cpu
)
6718 struct sched_domain
*sd
= sd_init(tl
, cpu
);
6722 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
6724 sd
->level
= child
->level
+ 1;
6725 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
6729 if (!cpumask_subset(sched_domain_span(child
),
6730 sched_domain_span(sd
))) {
6731 pr_err("BUG: arch topology borken\n");
6732 #ifdef CONFIG_SCHED_DEBUG
6733 pr_err(" the %s domain not a subset of the %s domain\n",
6734 child
->name
, sd
->name
);
6736 /* Fixup, ensure @sd has at least @child cpus. */
6737 cpumask_or(sched_domain_span(sd
),
6738 sched_domain_span(sd
),
6739 sched_domain_span(child
));
6743 set_domain_attribute(sd
, attr
);
6749 * Build sched domains for a given set of cpus and attach the sched domains
6750 * to the individual cpus
6752 static int build_sched_domains(const struct cpumask
*cpu_map
,
6753 struct sched_domain_attr
*attr
)
6755 enum s_alloc alloc_state
;
6756 struct sched_domain
*sd
;
6758 int i
, ret
= -ENOMEM
;
6760 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
6761 if (alloc_state
!= sa_rootdomain
)
6764 /* Set up domains for cpus specified by the cpu_map. */
6765 for_each_cpu(i
, cpu_map
) {
6766 struct sched_domain_topology_level
*tl
;
6769 for_each_sd_topology(tl
) {
6770 sd
= build_sched_domain(tl
, cpu_map
, attr
, sd
, i
);
6771 if (tl
== sched_domain_topology
)
6772 *per_cpu_ptr(d
.sd
, i
) = sd
;
6773 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
6774 sd
->flags
|= SD_OVERLAP
;
6775 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
6780 /* Build the groups for the domains */
6781 for_each_cpu(i
, cpu_map
) {
6782 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6783 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
6784 if (sd
->flags
& SD_OVERLAP
) {
6785 if (build_overlap_sched_groups(sd
, i
))
6788 if (build_sched_groups(sd
, i
))
6794 /* Calculate CPU capacity for physical packages and nodes */
6795 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
6796 if (!cpumask_test_cpu(i
, cpu_map
))
6799 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
6800 claim_allocations(i
, sd
);
6801 init_sched_groups_capacity(i
, sd
);
6805 /* Attach the domains */
6807 for_each_cpu(i
, cpu_map
) {
6808 sd
= *per_cpu_ptr(d
.sd
, i
);
6809 cpu_attach_domain(sd
, d
.rd
, i
);
6815 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
6819 static cpumask_var_t
*doms_cur
; /* current sched domains */
6820 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
6821 static struct sched_domain_attr
*dattr_cur
;
6822 /* attribues of custom domains in 'doms_cur' */
6825 * Special case: If a kmalloc of a doms_cur partition (array of
6826 * cpumask) fails, then fallback to a single sched domain,
6827 * as determined by the single cpumask fallback_doms.
6829 static cpumask_var_t fallback_doms
;
6832 * arch_update_cpu_topology lets virtualized architectures update the
6833 * cpu core maps. It is supposed to return 1 if the topology changed
6834 * or 0 if it stayed the same.
6836 int __weak
arch_update_cpu_topology(void)
6841 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
6844 cpumask_var_t
*doms
;
6846 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
6849 for (i
= 0; i
< ndoms
; i
++) {
6850 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
6851 free_sched_domains(doms
, i
);
6858 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
6861 for (i
= 0; i
< ndoms
; i
++)
6862 free_cpumask_var(doms
[i
]);
6867 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6868 * For now this just excludes isolated cpus, but could be used to
6869 * exclude other special cases in the future.
6871 static int init_sched_domains(const struct cpumask
*cpu_map
)
6875 arch_update_cpu_topology();
6877 doms_cur
= alloc_sched_domains(ndoms_cur
);
6879 doms_cur
= &fallback_doms
;
6880 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
6881 err
= build_sched_domains(doms_cur
[0], NULL
);
6882 register_sched_domain_sysctl();
6888 * Detach sched domains from a group of cpus specified in cpu_map
6889 * These cpus will now be attached to the NULL domain
6891 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
6896 for_each_cpu(i
, cpu_map
)
6897 cpu_attach_domain(NULL
, &def_root_domain
, i
);
6901 /* handle null as "default" */
6902 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
6903 struct sched_domain_attr
*new, int idx_new
)
6905 struct sched_domain_attr tmp
;
6912 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
6913 new ? (new + idx_new
) : &tmp
,
6914 sizeof(struct sched_domain_attr
));
6918 * Partition sched domains as specified by the 'ndoms_new'
6919 * cpumasks in the array doms_new[] of cpumasks. This compares
6920 * doms_new[] to the current sched domain partitioning, doms_cur[].
6921 * It destroys each deleted domain and builds each new domain.
6923 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
6924 * The masks don't intersect (don't overlap.) We should setup one
6925 * sched domain for each mask. CPUs not in any of the cpumasks will
6926 * not be load balanced. If the same cpumask appears both in the
6927 * current 'doms_cur' domains and in the new 'doms_new', we can leave
6930 * The passed in 'doms_new' should be allocated using
6931 * alloc_sched_domains. This routine takes ownership of it and will
6932 * free_sched_domains it when done with it. If the caller failed the
6933 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
6934 * and partition_sched_domains() will fallback to the single partition
6935 * 'fallback_doms', it also forces the domains to be rebuilt.
6937 * If doms_new == NULL it will be replaced with cpu_online_mask.
6938 * ndoms_new == 0 is a special case for destroying existing domains,
6939 * and it will not create the default domain.
6941 * Call with hotplug lock held
6943 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
6944 struct sched_domain_attr
*dattr_new
)
6949 mutex_lock(&sched_domains_mutex
);
6951 /* always unregister in case we don't destroy any domains */
6952 unregister_sched_domain_sysctl();
6954 /* Let architecture update cpu core mappings. */
6955 new_topology
= arch_update_cpu_topology();
6957 n
= doms_new
? ndoms_new
: 0;
6959 /* Destroy deleted domains */
6960 for (i
= 0; i
< ndoms_cur
; i
++) {
6961 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6962 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
6963 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
6966 /* no match - a current sched domain not in new doms_new[] */
6967 detach_destroy_domains(doms_cur
[i
]);
6973 if (doms_new
== NULL
) {
6975 doms_new
= &fallback_doms
;
6976 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
6977 WARN_ON_ONCE(dattr_new
);
6980 /* Build new domains */
6981 for (i
= 0; i
< ndoms_new
; i
++) {
6982 for (j
= 0; j
< n
&& !new_topology
; j
++) {
6983 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
6984 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
6987 /* no match - add a new doms_new */
6988 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
6993 /* Remember the new sched domains */
6994 if (doms_cur
!= &fallback_doms
)
6995 free_sched_domains(doms_cur
, ndoms_cur
);
6996 kfree(dattr_cur
); /* kfree(NULL) is safe */
6997 doms_cur
= doms_new
;
6998 dattr_cur
= dattr_new
;
6999 ndoms_cur
= ndoms_new
;
7001 register_sched_domain_sysctl();
7003 mutex_unlock(&sched_domains_mutex
);
7006 static int num_cpus_frozen
; /* used to mark begin/end of suspend/resume */
7009 * Update cpusets according to cpu_active mask. If cpusets are
7010 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7011 * around partition_sched_domains().
7013 * If we come here as part of a suspend/resume, don't touch cpusets because we
7014 * want to restore it back to its original state upon resume anyway.
7016 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
7020 case CPU_ONLINE_FROZEN
:
7021 case CPU_DOWN_FAILED_FROZEN
:
7024 * num_cpus_frozen tracks how many CPUs are involved in suspend
7025 * resume sequence. As long as this is not the last online
7026 * operation in the resume sequence, just build a single sched
7027 * domain, ignoring cpusets.
7030 if (likely(num_cpus_frozen
)) {
7031 partition_sched_domains(1, NULL
, NULL
);
7036 * This is the last CPU online operation. So fall through and
7037 * restore the original sched domains by considering the
7038 * cpuset configurations.
7042 case CPU_DOWN_FAILED
:
7043 cpuset_update_active_cpus(true);
7051 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7055 case CPU_DOWN_PREPARE
:
7056 cpuset_update_active_cpus(false);
7058 case CPU_DOWN_PREPARE_FROZEN
:
7060 partition_sched_domains(1, NULL
, NULL
);
7068 void __init
sched_init_smp(void)
7070 cpumask_var_t non_isolated_cpus
;
7072 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7073 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7078 * There's no userspace yet to cause hotplug operations; hence all the
7079 * cpu masks are stable and all blatant races in the below code cannot
7082 mutex_lock(&sched_domains_mutex
);
7083 init_sched_domains(cpu_active_mask
);
7084 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7085 if (cpumask_empty(non_isolated_cpus
))
7086 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7087 mutex_unlock(&sched_domains_mutex
);
7089 hotcpu_notifier(sched_domains_numa_masks_update
, CPU_PRI_SCHED_ACTIVE
);
7090 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
7091 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
7095 /* Move init over to a non-isolated CPU */
7096 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7098 sched_init_granularity();
7099 free_cpumask_var(non_isolated_cpus
);
7101 init_sched_rt_class();
7102 init_sched_dl_class();
7105 void __init
sched_init_smp(void)
7107 sched_init_granularity();
7109 #endif /* CONFIG_SMP */
7111 const_debug
unsigned int sysctl_timer_migration
= 1;
7113 int in_sched_functions(unsigned long addr
)
7115 return in_lock_functions(addr
) ||
7116 (addr
>= (unsigned long)__sched_text_start
7117 && addr
< (unsigned long)__sched_text_end
);
7120 #ifdef CONFIG_CGROUP_SCHED
7122 * Default task group.
7123 * Every task in system belongs to this group at bootup.
7125 struct task_group root_task_group
;
7126 LIST_HEAD(task_groups
);
7129 DECLARE_PER_CPU(cpumask_var_t
, load_balance_mask
);
7131 void __init
sched_init(void)
7134 unsigned long alloc_size
= 0, ptr
;
7136 #ifdef CONFIG_FAIR_GROUP_SCHED
7137 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7139 #ifdef CONFIG_RT_GROUP_SCHED
7140 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7143 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
7145 #ifdef CONFIG_FAIR_GROUP_SCHED
7146 root_task_group
.se
= (struct sched_entity
**)ptr
;
7147 ptr
+= nr_cpu_ids
* sizeof(void **);
7149 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7150 ptr
+= nr_cpu_ids
* sizeof(void **);
7152 #endif /* CONFIG_FAIR_GROUP_SCHED */
7153 #ifdef CONFIG_RT_GROUP_SCHED
7154 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7155 ptr
+= nr_cpu_ids
* sizeof(void **);
7157 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7158 ptr
+= nr_cpu_ids
* sizeof(void **);
7160 #endif /* CONFIG_RT_GROUP_SCHED */
7162 #ifdef CONFIG_CPUMASK_OFFSTACK
7163 for_each_possible_cpu(i
) {
7164 per_cpu(load_balance_mask
, i
) = (cpumask_var_t
)kzalloc_node(
7165 cpumask_size(), GFP_KERNEL
, cpu_to_node(i
));
7167 #endif /* CONFIG_CPUMASK_OFFSTACK */
7169 init_rt_bandwidth(&def_rt_bandwidth
,
7170 global_rt_period(), global_rt_runtime());
7171 init_dl_bandwidth(&def_dl_bandwidth
,
7172 global_rt_period(), global_rt_runtime());
7175 init_defrootdomain();
7178 #ifdef CONFIG_RT_GROUP_SCHED
7179 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7180 global_rt_period(), global_rt_runtime());
7181 #endif /* CONFIG_RT_GROUP_SCHED */
7183 #ifdef CONFIG_CGROUP_SCHED
7184 list_add(&root_task_group
.list
, &task_groups
);
7185 INIT_LIST_HEAD(&root_task_group
.children
);
7186 INIT_LIST_HEAD(&root_task_group
.siblings
);
7187 autogroup_init(&init_task
);
7189 #endif /* CONFIG_CGROUP_SCHED */
7191 for_each_possible_cpu(i
) {
7195 raw_spin_lock_init(&rq
->lock
);
7197 rq
->calc_load_active
= 0;
7198 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
7199 init_cfs_rq(&rq
->cfs
);
7200 init_rt_rq(&rq
->rt
, rq
);
7201 init_dl_rq(&rq
->dl
, rq
);
7202 #ifdef CONFIG_FAIR_GROUP_SCHED
7203 root_task_group
.shares
= ROOT_TASK_GROUP_LOAD
;
7204 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7206 * How much cpu bandwidth does root_task_group get?
7208 * In case of task-groups formed thr' the cgroup filesystem, it
7209 * gets 100% of the cpu resources in the system. This overall
7210 * system cpu resource is divided among the tasks of
7211 * root_task_group and its child task-groups in a fair manner,
7212 * based on each entity's (task or task-group's) weight
7213 * (se->load.weight).
7215 * In other words, if root_task_group has 10 tasks of weight
7216 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7217 * then A0's share of the cpu resource is:
7219 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7221 * We achieve this by letting root_task_group's tasks sit
7222 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
7224 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
7225 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
7226 #endif /* CONFIG_FAIR_GROUP_SCHED */
7228 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7229 #ifdef CONFIG_RT_GROUP_SCHED
7230 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
7233 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7234 rq
->cpu_load
[j
] = 0;
7236 rq
->last_load_update_tick
= jiffies
;
7241 rq
->cpu_capacity
= SCHED_CAPACITY_SCALE
;
7242 rq
->post_schedule
= 0;
7243 rq
->active_balance
= 0;
7244 rq
->next_balance
= jiffies
;
7249 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7250 rq
->max_idle_balance_cost
= sysctl_sched_migration_cost
;
7252 INIT_LIST_HEAD(&rq
->cfs_tasks
);
7254 rq_attach_root(rq
, &def_root_domain
);
7255 #ifdef CONFIG_NO_HZ_COMMON
7258 #ifdef CONFIG_NO_HZ_FULL
7259 rq
->last_sched_tick
= 0;
7263 atomic_set(&rq
->nr_iowait
, 0);
7266 set_load_weight(&init_task
);
7268 #ifdef CONFIG_PREEMPT_NOTIFIERS
7269 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7273 * The boot idle thread does lazy MMU switching as well:
7275 atomic_inc(&init_mm
.mm_count
);
7276 enter_lazy_tlb(&init_mm
, current
);
7279 * Make us the idle thread. Technically, schedule() should not be
7280 * called from this thread, however somewhere below it might be,
7281 * but because we are the idle thread, we just pick up running again
7282 * when this runqueue becomes "idle".
7284 init_idle(current
, smp_processor_id());
7286 calc_load_update
= jiffies
+ LOAD_FREQ
;
7289 * During early bootup we pretend to be a normal task:
7291 current
->sched_class
= &fair_sched_class
;
7294 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
7295 /* May be allocated at isolcpus cmdline parse time */
7296 if (cpu_isolated_map
== NULL
)
7297 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7298 idle_thread_set_boot_cpu();
7299 set_cpu_rq_start_time();
7301 init_sched_fair_class();
7303 scheduler_running
= 1;
7306 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
7307 static inline int preempt_count_equals(int preempt_offset
)
7309 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7311 return (nested
== preempt_offset
);
7314 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7317 * Blocking primitives will set (and therefore destroy) current->state,
7318 * since we will exit with TASK_RUNNING make sure we enter with it,
7319 * otherwise we will destroy state.
7321 WARN_ONCE(current
->state
!= TASK_RUNNING
&& current
->task_state_change
,
7322 "do not call blocking ops when !TASK_RUNNING; "
7323 "state=%lx set at [<%p>] %pS\n",
7325 (void *)current
->task_state_change
,
7326 (void *)current
->task_state_change
);
7328 ___might_sleep(file
, line
, preempt_offset
);
7330 EXPORT_SYMBOL(__might_sleep
);
7332 void ___might_sleep(const char *file
, int line
, int preempt_offset
)
7334 static unsigned long prev_jiffy
; /* ratelimiting */
7336 rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
7337 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled() &&
7338 !is_idle_task(current
)) ||
7339 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7341 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7343 prev_jiffy
= jiffies
;
7346 "BUG: sleeping function called from invalid context at %s:%d\n",
7349 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7350 in_atomic(), irqs_disabled(),
7351 current
->pid
, current
->comm
);
7353 debug_show_held_locks(current
);
7354 if (irqs_disabled())
7355 print_irqtrace_events(current
);
7356 #ifdef CONFIG_DEBUG_PREEMPT
7357 if (!preempt_count_equals(preempt_offset
)) {
7358 pr_err("Preemption disabled at:");
7359 print_ip_sym(current
->preempt_disable_ip
);
7365 EXPORT_SYMBOL(___might_sleep
);
7368 #ifdef CONFIG_MAGIC_SYSRQ
7369 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7371 const struct sched_class
*prev_class
= p
->sched_class
;
7372 struct sched_attr attr
= {
7373 .sched_policy
= SCHED_NORMAL
,
7375 int old_prio
= p
->prio
;
7378 queued
= task_on_rq_queued(p
);
7380 dequeue_task(rq
, p
, 0);
7381 __setscheduler(rq
, p
, &attr
);
7383 enqueue_task(rq
, p
, 0);
7387 check_class_changed(rq
, p
, prev_class
, old_prio
);
7390 void normalize_rt_tasks(void)
7392 struct task_struct
*g
, *p
;
7393 unsigned long flags
;
7396 read_lock(&tasklist_lock
);
7397 for_each_process_thread(g
, p
) {
7399 * Only normalize user tasks:
7401 if (p
->flags
& PF_KTHREAD
)
7404 p
->se
.exec_start
= 0;
7405 #ifdef CONFIG_SCHEDSTATS
7406 p
->se
.statistics
.wait_start
= 0;
7407 p
->se
.statistics
.sleep_start
= 0;
7408 p
->se
.statistics
.block_start
= 0;
7411 if (!dl_task(p
) && !rt_task(p
)) {
7413 * Renice negative nice level userspace
7416 if (task_nice(p
) < 0)
7417 set_user_nice(p
, 0);
7421 rq
= task_rq_lock(p
, &flags
);
7422 normalize_task(rq
, p
);
7423 task_rq_unlock(rq
, p
, &flags
);
7425 read_unlock(&tasklist_lock
);
7428 #endif /* CONFIG_MAGIC_SYSRQ */
7430 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
7432 * These functions are only useful for the IA64 MCA handling, or kdb.
7434 * They can only be called when the whole system has been
7435 * stopped - every CPU needs to be quiescent, and no scheduling
7436 * activity can take place. Using them for anything else would
7437 * be a serious bug, and as a result, they aren't even visible
7438 * under any other configuration.
7442 * curr_task - return the current task for a given cpu.
7443 * @cpu: the processor in question.
7445 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7447 * Return: The current task for @cpu.
7449 struct task_struct
*curr_task(int cpu
)
7451 return cpu_curr(cpu
);
7454 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
7458 * set_curr_task - set the current task for a given cpu.
7459 * @cpu: the processor in question.
7460 * @p: the task pointer to set.
7462 * Description: This function must only be used when non-maskable interrupts
7463 * are serviced on a separate stack. It allows the architecture to switch the
7464 * notion of the current task on a cpu in a non-blocking manner. This function
7465 * must be called with all CPU's synchronized, and interrupts disabled, the
7466 * and caller must save the original value of the current task (see
7467 * curr_task() above) and restore that value before reenabling interrupts and
7468 * re-starting the system.
7470 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7472 void set_curr_task(int cpu
, struct task_struct
*p
)
7479 #ifdef CONFIG_CGROUP_SCHED
7480 /* task_group_lock serializes the addition/removal of task groups */
7481 static DEFINE_SPINLOCK(task_group_lock
);
7483 static void free_sched_group(struct task_group
*tg
)
7485 free_fair_sched_group(tg
);
7486 free_rt_sched_group(tg
);
7491 /* allocate runqueue etc for a new task group */
7492 struct task_group
*sched_create_group(struct task_group
*parent
)
7494 struct task_group
*tg
;
7496 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7498 return ERR_PTR(-ENOMEM
);
7500 if (!alloc_fair_sched_group(tg
, parent
))
7503 if (!alloc_rt_sched_group(tg
, parent
))
7509 free_sched_group(tg
);
7510 return ERR_PTR(-ENOMEM
);
7513 void sched_online_group(struct task_group
*tg
, struct task_group
*parent
)
7515 unsigned long flags
;
7517 spin_lock_irqsave(&task_group_lock
, flags
);
7518 list_add_rcu(&tg
->list
, &task_groups
);
7520 WARN_ON(!parent
); /* root should already exist */
7522 tg
->parent
= parent
;
7523 INIT_LIST_HEAD(&tg
->children
);
7524 list_add_rcu(&tg
->siblings
, &parent
->children
);
7525 spin_unlock_irqrestore(&task_group_lock
, flags
);
7528 /* rcu callback to free various structures associated with a task group */
7529 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7531 /* now it should be safe to free those cfs_rqs */
7532 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7535 /* Destroy runqueue etc associated with a task group */
7536 void sched_destroy_group(struct task_group
*tg
)
7538 /* wait for possible concurrent references to cfs_rqs complete */
7539 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7542 void sched_offline_group(struct task_group
*tg
)
7544 unsigned long flags
;
7547 /* end participation in shares distribution */
7548 for_each_possible_cpu(i
)
7549 unregister_fair_sched_group(tg
, i
);
7551 spin_lock_irqsave(&task_group_lock
, flags
);
7552 list_del_rcu(&tg
->list
);
7553 list_del_rcu(&tg
->siblings
);
7554 spin_unlock_irqrestore(&task_group_lock
, flags
);
7557 /* change task's runqueue when it moves between groups.
7558 * The caller of this function should have put the task in its new group
7559 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7560 * reflect its new group.
7562 void sched_move_task(struct task_struct
*tsk
)
7564 struct task_group
*tg
;
7565 int queued
, running
;
7566 unsigned long flags
;
7569 rq
= task_rq_lock(tsk
, &flags
);
7571 running
= task_current(rq
, tsk
);
7572 queued
= task_on_rq_queued(tsk
);
7575 dequeue_task(rq
, tsk
, 0);
7576 if (unlikely(running
))
7577 put_prev_task(rq
, tsk
);
7580 * All callers are synchronized by task_rq_lock(); we do not use RCU
7581 * which is pointless here. Thus, we pass "true" to task_css_check()
7582 * to prevent lockdep warnings.
7584 tg
= container_of(task_css_check(tsk
, cpu_cgrp_id
, true),
7585 struct task_group
, css
);
7586 tg
= autogroup_task_group(tsk
, tg
);
7587 tsk
->sched_task_group
= tg
;
7589 #ifdef CONFIG_FAIR_GROUP_SCHED
7590 if (tsk
->sched_class
->task_move_group
)
7591 tsk
->sched_class
->task_move_group(tsk
, queued
);
7594 set_task_rq(tsk
, task_cpu(tsk
));
7596 if (unlikely(running
))
7597 tsk
->sched_class
->set_curr_task(rq
);
7599 enqueue_task(rq
, tsk
, 0);
7601 task_rq_unlock(rq
, tsk
, &flags
);
7603 #endif /* CONFIG_CGROUP_SCHED */
7605 #ifdef CONFIG_RT_GROUP_SCHED
7607 * Ensure that the real time constraints are schedulable.
7609 static DEFINE_MUTEX(rt_constraints_mutex
);
7611 /* Must be called with tasklist_lock held */
7612 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7614 struct task_struct
*g
, *p
;
7616 for_each_process_thread(g
, p
) {
7617 if (rt_task(p
) && task_group(p
) == tg
)
7624 struct rt_schedulable_data
{
7625 struct task_group
*tg
;
7630 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
7632 struct rt_schedulable_data
*d
= data
;
7633 struct task_group
*child
;
7634 unsigned long total
, sum
= 0;
7635 u64 period
, runtime
;
7637 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7638 runtime
= tg
->rt_bandwidth
.rt_runtime
;
7641 period
= d
->rt_period
;
7642 runtime
= d
->rt_runtime
;
7646 * Cannot have more runtime than the period.
7648 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
7652 * Ensure we don't starve existing RT tasks.
7654 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
7657 total
= to_ratio(period
, runtime
);
7660 * Nobody can have more than the global setting allows.
7662 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
7666 * The sum of our children's runtime should not exceed our own.
7668 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
7669 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
7670 runtime
= child
->rt_bandwidth
.rt_runtime
;
7672 if (child
== d
->tg
) {
7673 period
= d
->rt_period
;
7674 runtime
= d
->rt_runtime
;
7677 sum
+= to_ratio(period
, runtime
);
7686 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7690 struct rt_schedulable_data data
= {
7692 .rt_period
= period
,
7693 .rt_runtime
= runtime
,
7697 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
7703 static int tg_set_rt_bandwidth(struct task_group
*tg
,
7704 u64 rt_period
, u64 rt_runtime
)
7708 mutex_lock(&rt_constraints_mutex
);
7709 read_lock(&tasklist_lock
);
7710 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
7714 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7715 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7716 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7718 for_each_possible_cpu(i
) {
7719 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
7721 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7722 rt_rq
->rt_runtime
= rt_runtime
;
7723 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7725 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
7727 read_unlock(&tasklist_lock
);
7728 mutex_unlock(&rt_constraints_mutex
);
7733 static int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
7735 u64 rt_runtime
, rt_period
;
7737 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7738 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
7739 if (rt_runtime_us
< 0)
7740 rt_runtime
= RUNTIME_INF
;
7742 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7745 static long sched_group_rt_runtime(struct task_group
*tg
)
7749 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
7752 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
7753 do_div(rt_runtime_us
, NSEC_PER_USEC
);
7754 return rt_runtime_us
;
7757 static int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
7759 u64 rt_runtime
, rt_period
;
7761 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
7762 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7767 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
7770 static long sched_group_rt_period(struct task_group
*tg
)
7774 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
7775 do_div(rt_period_us
, NSEC_PER_USEC
);
7776 return rt_period_us
;
7778 #endif /* CONFIG_RT_GROUP_SCHED */
7780 #ifdef CONFIG_RT_GROUP_SCHED
7781 static int sched_rt_global_constraints(void)
7785 mutex_lock(&rt_constraints_mutex
);
7786 read_lock(&tasklist_lock
);
7787 ret
= __rt_schedulable(NULL
, 0, 0);
7788 read_unlock(&tasklist_lock
);
7789 mutex_unlock(&rt_constraints_mutex
);
7794 static int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
7796 /* Don't accept realtime tasks when there is no way for them to run */
7797 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
7803 #else /* !CONFIG_RT_GROUP_SCHED */
7804 static int sched_rt_global_constraints(void)
7806 unsigned long flags
;
7809 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7810 for_each_possible_cpu(i
) {
7811 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
7813 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
7814 rt_rq
->rt_runtime
= global_rt_runtime();
7815 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
7817 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
7821 #endif /* CONFIG_RT_GROUP_SCHED */
7823 static int sched_dl_global_constraints(void)
7825 u64 runtime
= global_rt_runtime();
7826 u64 period
= global_rt_period();
7827 u64 new_bw
= to_ratio(period
, runtime
);
7830 unsigned long flags
;
7833 * Here we want to check the bandwidth not being set to some
7834 * value smaller than the currently allocated bandwidth in
7835 * any of the root_domains.
7837 * FIXME: Cycling on all the CPUs is overdoing, but simpler than
7838 * cycling on root_domains... Discussion on different/better
7839 * solutions is welcome!
7841 for_each_possible_cpu(cpu
) {
7842 rcu_read_lock_sched();
7843 dl_b
= dl_bw_of(cpu
);
7845 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7846 if (new_bw
< dl_b
->total_bw
)
7848 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7850 rcu_read_unlock_sched();
7859 static void sched_dl_do_global(void)
7864 unsigned long flags
;
7866 def_dl_bandwidth
.dl_period
= global_rt_period();
7867 def_dl_bandwidth
.dl_runtime
= global_rt_runtime();
7869 if (global_rt_runtime() != RUNTIME_INF
)
7870 new_bw
= to_ratio(global_rt_period(), global_rt_runtime());
7873 * FIXME: As above...
7875 for_each_possible_cpu(cpu
) {
7876 rcu_read_lock_sched();
7877 dl_b
= dl_bw_of(cpu
);
7879 raw_spin_lock_irqsave(&dl_b
->lock
, flags
);
7881 raw_spin_unlock_irqrestore(&dl_b
->lock
, flags
);
7883 rcu_read_unlock_sched();
7887 static int sched_rt_global_validate(void)
7889 if (sysctl_sched_rt_period
<= 0)
7892 if ((sysctl_sched_rt_runtime
!= RUNTIME_INF
) &&
7893 (sysctl_sched_rt_runtime
> sysctl_sched_rt_period
))
7899 static void sched_rt_do_global(void)
7901 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
7902 def_rt_bandwidth
.rt_period
= ns_to_ktime(global_rt_period());
7905 int sched_rt_handler(struct ctl_table
*table
, int write
,
7906 void __user
*buffer
, size_t *lenp
,
7909 int old_period
, old_runtime
;
7910 static DEFINE_MUTEX(mutex
);
7914 old_period
= sysctl_sched_rt_period
;
7915 old_runtime
= sysctl_sched_rt_runtime
;
7917 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7919 if (!ret
&& write
) {
7920 ret
= sched_rt_global_validate();
7924 ret
= sched_rt_global_constraints();
7928 ret
= sched_dl_global_constraints();
7932 sched_rt_do_global();
7933 sched_dl_do_global();
7937 sysctl_sched_rt_period
= old_period
;
7938 sysctl_sched_rt_runtime
= old_runtime
;
7940 mutex_unlock(&mutex
);
7945 int sched_rr_handler(struct ctl_table
*table
, int write
,
7946 void __user
*buffer
, size_t *lenp
,
7950 static DEFINE_MUTEX(mutex
);
7953 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
7954 /* make sure that internally we keep jiffies */
7955 /* also, writing zero resets timeslice to default */
7956 if (!ret
&& write
) {
7957 sched_rr_timeslice
= sched_rr_timeslice
<= 0 ?
7958 RR_TIMESLICE
: msecs_to_jiffies(sched_rr_timeslice
);
7960 mutex_unlock(&mutex
);
7964 #ifdef CONFIG_CGROUP_SCHED
7966 static inline struct task_group
*css_tg(struct cgroup_subsys_state
*css
)
7968 return css
? container_of(css
, struct task_group
, css
) : NULL
;
7971 static struct cgroup_subsys_state
*
7972 cpu_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
7974 struct task_group
*parent
= css_tg(parent_css
);
7975 struct task_group
*tg
;
7978 /* This is early initialization for the top cgroup */
7979 return &root_task_group
.css
;
7982 tg
= sched_create_group(parent
);
7984 return ERR_PTR(-ENOMEM
);
7989 static int cpu_cgroup_css_online(struct cgroup_subsys_state
*css
)
7991 struct task_group
*tg
= css_tg(css
);
7992 struct task_group
*parent
= css_tg(css
->parent
);
7995 sched_online_group(tg
, parent
);
7999 static void cpu_cgroup_css_free(struct cgroup_subsys_state
*css
)
8001 struct task_group
*tg
= css_tg(css
);
8003 sched_destroy_group(tg
);
8006 static void cpu_cgroup_css_offline(struct cgroup_subsys_state
*css
)
8008 struct task_group
*tg
= css_tg(css
);
8010 sched_offline_group(tg
);
8013 static void cpu_cgroup_fork(struct task_struct
*task
)
8015 sched_move_task(task
);
8018 static int cpu_cgroup_can_attach(struct cgroup_subsys_state
*css
,
8019 struct cgroup_taskset
*tset
)
8021 struct task_struct
*task
;
8023 cgroup_taskset_for_each(task
, tset
) {
8024 #ifdef CONFIG_RT_GROUP_SCHED
8025 if (!sched_rt_can_attach(css_tg(css
), task
))
8028 /* We don't support RT-tasks being in separate groups */
8029 if (task
->sched_class
!= &fair_sched_class
)
8036 static void cpu_cgroup_attach(struct cgroup_subsys_state
*css
,
8037 struct cgroup_taskset
*tset
)
8039 struct task_struct
*task
;
8041 cgroup_taskset_for_each(task
, tset
)
8042 sched_move_task(task
);
8045 static void cpu_cgroup_exit(struct cgroup_subsys_state
*css
,
8046 struct cgroup_subsys_state
*old_css
,
8047 struct task_struct
*task
)
8050 * cgroup_exit() is called in the copy_process() failure path.
8051 * Ignore this case since the task hasn't ran yet, this avoids
8052 * trying to poke a half freed task state from generic code.
8054 if (!(task
->flags
& PF_EXITING
))
8057 sched_move_task(task
);
8060 #ifdef CONFIG_FAIR_GROUP_SCHED
8061 static int cpu_shares_write_u64(struct cgroup_subsys_state
*css
,
8062 struct cftype
*cftype
, u64 shareval
)
8064 return sched_group_set_shares(css_tg(css
), scale_load(shareval
));
8067 static u64
cpu_shares_read_u64(struct cgroup_subsys_state
*css
,
8070 struct task_group
*tg
= css_tg(css
);
8072 return (u64
) scale_load_down(tg
->shares
);
8075 #ifdef CONFIG_CFS_BANDWIDTH
8076 static DEFINE_MUTEX(cfs_constraints_mutex
);
8078 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
8079 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
8081 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
8083 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
8085 int i
, ret
= 0, runtime_enabled
, runtime_was_enabled
;
8086 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8088 if (tg
== &root_task_group
)
8092 * Ensure we have at some amount of bandwidth every period. This is
8093 * to prevent reaching a state of large arrears when throttled via
8094 * entity_tick() resulting in prolonged exit starvation.
8096 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
8100 * Likewise, bound things on the otherside by preventing insane quota
8101 * periods. This also allows us to normalize in computing quota
8104 if (period
> max_cfs_quota_period
)
8108 * Prevent race between setting of cfs_rq->runtime_enabled and
8109 * unthrottle_offline_cfs_rqs().
8112 mutex_lock(&cfs_constraints_mutex
);
8113 ret
= __cfs_schedulable(tg
, period
, quota
);
8117 runtime_enabled
= quota
!= RUNTIME_INF
;
8118 runtime_was_enabled
= cfs_b
->quota
!= RUNTIME_INF
;
8120 * If we need to toggle cfs_bandwidth_used, off->on must occur
8121 * before making related changes, and on->off must occur afterwards
8123 if (runtime_enabled
&& !runtime_was_enabled
)
8124 cfs_bandwidth_usage_inc();
8125 raw_spin_lock_irq(&cfs_b
->lock
);
8126 cfs_b
->period
= ns_to_ktime(period
);
8127 cfs_b
->quota
= quota
;
8129 __refill_cfs_bandwidth_runtime(cfs_b
);
8130 /* restart the period timer (if active) to handle new period expiry */
8131 if (runtime_enabled
&& cfs_b
->timer_active
) {
8132 /* force a reprogram */
8133 __start_cfs_bandwidth(cfs_b
, true);
8135 raw_spin_unlock_irq(&cfs_b
->lock
);
8137 for_each_online_cpu(i
) {
8138 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
8139 struct rq
*rq
= cfs_rq
->rq
;
8141 raw_spin_lock_irq(&rq
->lock
);
8142 cfs_rq
->runtime_enabled
= runtime_enabled
;
8143 cfs_rq
->runtime_remaining
= 0;
8145 if (cfs_rq
->throttled
)
8146 unthrottle_cfs_rq(cfs_rq
);
8147 raw_spin_unlock_irq(&rq
->lock
);
8149 if (runtime_was_enabled
&& !runtime_enabled
)
8150 cfs_bandwidth_usage_dec();
8152 mutex_unlock(&cfs_constraints_mutex
);
8158 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
8162 period
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
8163 if (cfs_quota_us
< 0)
8164 quota
= RUNTIME_INF
;
8166 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
8168 return tg_set_cfs_bandwidth(tg
, period
, quota
);
8171 long tg_get_cfs_quota(struct task_group
*tg
)
8175 if (tg
->cfs_bandwidth
.quota
== RUNTIME_INF
)
8178 quota_us
= tg
->cfs_bandwidth
.quota
;
8179 do_div(quota_us
, NSEC_PER_USEC
);
8184 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
8188 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
8189 quota
= tg
->cfs_bandwidth
.quota
;
8191 return tg_set_cfs_bandwidth(tg
, period
, quota
);
8194 long tg_get_cfs_period(struct task_group
*tg
)
8198 cfs_period_us
= ktime_to_ns(tg
->cfs_bandwidth
.period
);
8199 do_div(cfs_period_us
, NSEC_PER_USEC
);
8201 return cfs_period_us
;
8204 static s64
cpu_cfs_quota_read_s64(struct cgroup_subsys_state
*css
,
8207 return tg_get_cfs_quota(css_tg(css
));
8210 static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state
*css
,
8211 struct cftype
*cftype
, s64 cfs_quota_us
)
8213 return tg_set_cfs_quota(css_tg(css
), cfs_quota_us
);
8216 static u64
cpu_cfs_period_read_u64(struct cgroup_subsys_state
*css
,
8219 return tg_get_cfs_period(css_tg(css
));
8222 static int cpu_cfs_period_write_u64(struct cgroup_subsys_state
*css
,
8223 struct cftype
*cftype
, u64 cfs_period_us
)
8225 return tg_set_cfs_period(css_tg(css
), cfs_period_us
);
8228 struct cfs_schedulable_data
{
8229 struct task_group
*tg
;
8234 * normalize group quota/period to be quota/max_period
8235 * note: units are usecs
8237 static u64
normalize_cfs_quota(struct task_group
*tg
,
8238 struct cfs_schedulable_data
*d
)
8246 period
= tg_get_cfs_period(tg
);
8247 quota
= tg_get_cfs_quota(tg
);
8250 /* note: these should typically be equivalent */
8251 if (quota
== RUNTIME_INF
|| quota
== -1)
8254 return to_ratio(period
, quota
);
8257 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
8259 struct cfs_schedulable_data
*d
= data
;
8260 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8261 s64 quota
= 0, parent_quota
= -1;
8264 quota
= RUNTIME_INF
;
8266 struct cfs_bandwidth
*parent_b
= &tg
->parent
->cfs_bandwidth
;
8268 quota
= normalize_cfs_quota(tg
, d
);
8269 parent_quota
= parent_b
->hierarchical_quota
;
8272 * ensure max(child_quota) <= parent_quota, inherit when no
8275 if (quota
== RUNTIME_INF
)
8276 quota
= parent_quota
;
8277 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
8280 cfs_b
->hierarchical_quota
= quota
;
8285 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
8288 struct cfs_schedulable_data data
= {
8294 if (quota
!= RUNTIME_INF
) {
8295 do_div(data
.period
, NSEC_PER_USEC
);
8296 do_div(data
.quota
, NSEC_PER_USEC
);
8300 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
8306 static int cpu_stats_show(struct seq_file
*sf
, void *v
)
8308 struct task_group
*tg
= css_tg(seq_css(sf
));
8309 struct cfs_bandwidth
*cfs_b
= &tg
->cfs_bandwidth
;
8311 seq_printf(sf
, "nr_periods %d\n", cfs_b
->nr_periods
);
8312 seq_printf(sf
, "nr_throttled %d\n", cfs_b
->nr_throttled
);
8313 seq_printf(sf
, "throttled_time %llu\n", cfs_b
->throttled_time
);
8317 #endif /* CONFIG_CFS_BANDWIDTH */
8318 #endif /* CONFIG_FAIR_GROUP_SCHED */
8320 #ifdef CONFIG_RT_GROUP_SCHED
8321 static int cpu_rt_runtime_write(struct cgroup_subsys_state
*css
,
8322 struct cftype
*cft
, s64 val
)
8324 return sched_group_set_rt_runtime(css_tg(css
), val
);
8327 static s64
cpu_rt_runtime_read(struct cgroup_subsys_state
*css
,
8330 return sched_group_rt_runtime(css_tg(css
));
8333 static int cpu_rt_period_write_uint(struct cgroup_subsys_state
*css
,
8334 struct cftype
*cftype
, u64 rt_period_us
)
8336 return sched_group_set_rt_period(css_tg(css
), rt_period_us
);
8339 static u64
cpu_rt_period_read_uint(struct cgroup_subsys_state
*css
,
8342 return sched_group_rt_period(css_tg(css
));
8344 #endif /* CONFIG_RT_GROUP_SCHED */
8346 static struct cftype cpu_files
[] = {
8347 #ifdef CONFIG_FAIR_GROUP_SCHED
8350 .read_u64
= cpu_shares_read_u64
,
8351 .write_u64
= cpu_shares_write_u64
,
8354 #ifdef CONFIG_CFS_BANDWIDTH
8356 .name
= "cfs_quota_us",
8357 .read_s64
= cpu_cfs_quota_read_s64
,
8358 .write_s64
= cpu_cfs_quota_write_s64
,
8361 .name
= "cfs_period_us",
8362 .read_u64
= cpu_cfs_period_read_u64
,
8363 .write_u64
= cpu_cfs_period_write_u64
,
8367 .seq_show
= cpu_stats_show
,
8370 #ifdef CONFIG_RT_GROUP_SCHED
8372 .name
= "rt_runtime_us",
8373 .read_s64
= cpu_rt_runtime_read
,
8374 .write_s64
= cpu_rt_runtime_write
,
8377 .name
= "rt_period_us",
8378 .read_u64
= cpu_rt_period_read_uint
,
8379 .write_u64
= cpu_rt_period_write_uint
,
8385 struct cgroup_subsys cpu_cgrp_subsys
= {
8386 .css_alloc
= cpu_cgroup_css_alloc
,
8387 .css_free
= cpu_cgroup_css_free
,
8388 .css_online
= cpu_cgroup_css_online
,
8389 .css_offline
= cpu_cgroup_css_offline
,
8390 .fork
= cpu_cgroup_fork
,
8391 .can_attach
= cpu_cgroup_can_attach
,
8392 .attach
= cpu_cgroup_attach
,
8393 .exit
= cpu_cgroup_exit
,
8394 .legacy_cftypes
= cpu_files
,
8398 #endif /* CONFIG_CGROUP_SCHED */
8400 void dump_cpu_task(int cpu
)
8402 pr_info("Task dump for CPU %d:\n", cpu
);
8403 sched_show_task(cpu_curr(cpu
));