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/stop_machine.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/unistd.h>
67 #include <linux/pagemap.h>
68 #include <linux/hrtimer.h>
69 #include <linux/tick.h>
70 #include <linux/debugfs.h>
71 #include <linux/ctype.h>
72 #include <linux/ftrace.h>
73 #include <linux/slab.h>
76 #include <asm/irq_regs.h>
77 #include <asm/mutex.h>
78 #ifdef CONFIG_PARAVIRT
79 #include <asm/paravirt.h>
82 #include "sched_cpupri.h"
83 #include "workqueue_sched.h"
84 #include "sched_autogroup.h"
86 #define CREATE_TRACE_POINTS
87 #include <trace/events/sched.h>
90 * Convert user-nice values [ -20 ... 0 ... 19 ]
91 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
94 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
95 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
96 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
99 * 'User priority' is the nice value converted to something we
100 * can work with better when scaling various scheduler parameters,
101 * it's a [ 0 ... 39 ] range.
103 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
104 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
105 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
108 * Helpers for converting nanosecond timing to jiffy resolution
110 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
112 #define NICE_0_LOAD SCHED_LOAD_SCALE
113 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
116 * These are the 'tuning knobs' of the scheduler:
118 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
119 * Timeslices get refilled after they expire.
121 #define DEF_TIMESLICE (100 * HZ / 1000)
124 * single value that denotes runtime == period, ie unlimited time.
126 #define RUNTIME_INF ((u64)~0ULL)
128 static inline int rt_policy(int policy
)
130 if (policy
== SCHED_FIFO
|| policy
== SCHED_RR
)
135 static inline int task_has_rt_policy(struct task_struct
*p
)
137 return rt_policy(p
->policy
);
141 * This is the priority-queue data structure of the RT scheduling class:
143 struct rt_prio_array
{
144 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
145 struct list_head queue
[MAX_RT_PRIO
];
148 struct rt_bandwidth
{
149 /* nests inside the rq lock: */
150 raw_spinlock_t rt_runtime_lock
;
153 struct hrtimer rt_period_timer
;
156 static struct rt_bandwidth def_rt_bandwidth
;
158 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
160 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
162 struct rt_bandwidth
*rt_b
=
163 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
169 now
= hrtimer_cb_get_time(timer
);
170 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
175 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
178 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
182 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
184 rt_b
->rt_period
= ns_to_ktime(period
);
185 rt_b
->rt_runtime
= runtime
;
187 raw_spin_lock_init(&rt_b
->rt_runtime_lock
);
189 hrtimer_init(&rt_b
->rt_period_timer
,
190 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
191 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
194 static inline int rt_bandwidth_enabled(void)
196 return sysctl_sched_rt_runtime
>= 0;
199 static void start_bandwidth_timer(struct hrtimer
*period_timer
, ktime_t period
)
202 ktime_t soft
, hard
, now
;
205 if (hrtimer_active(period_timer
))
208 now
= hrtimer_cb_get_time(period_timer
);
209 hrtimer_forward(period_timer
, now
, period
);
211 soft
= hrtimer_get_softexpires(period_timer
);
212 hard
= hrtimer_get_expires(period_timer
);
213 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
214 __hrtimer_start_range_ns(period_timer
, soft
, delta
,
215 HRTIMER_MODE_ABS_PINNED
, 0);
219 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
221 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
224 if (hrtimer_active(&rt_b
->rt_period_timer
))
227 raw_spin_lock(&rt_b
->rt_runtime_lock
);
228 start_bandwidth_timer(&rt_b
->rt_period_timer
, rt_b
->rt_period
);
229 raw_spin_unlock(&rt_b
->rt_runtime_lock
);
232 #ifdef CONFIG_RT_GROUP_SCHED
233 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
235 hrtimer_cancel(&rt_b
->rt_period_timer
);
240 * sched_domains_mutex serializes calls to init_sched_domains,
241 * detach_destroy_domains and partition_sched_domains.
243 static DEFINE_MUTEX(sched_domains_mutex
);
245 #ifdef CONFIG_CGROUP_SCHED
247 #include <linux/cgroup.h>
251 static LIST_HEAD(task_groups
);
253 struct cfs_bandwidth
{
254 #ifdef CONFIG_CFS_BANDWIDTH
258 s64 hierarchal_quota
;
261 int idle
, timer_active
;
262 struct hrtimer period_timer
, slack_timer
;
263 struct list_head throttled_cfs_rq
;
266 int nr_periods
, nr_throttled
;
271 /* task group related information */
273 struct cgroup_subsys_state css
;
275 #ifdef CONFIG_FAIR_GROUP_SCHED
276 /* schedulable entities of this group on each cpu */
277 struct sched_entity
**se
;
278 /* runqueue "owned" by this group on each cpu */
279 struct cfs_rq
**cfs_rq
;
280 unsigned long shares
;
282 atomic_t load_weight
;
285 #ifdef CONFIG_RT_GROUP_SCHED
286 struct sched_rt_entity
**rt_se
;
287 struct rt_rq
**rt_rq
;
289 struct rt_bandwidth rt_bandwidth
;
293 struct list_head list
;
295 struct task_group
*parent
;
296 struct list_head siblings
;
297 struct list_head children
;
299 #ifdef CONFIG_SCHED_AUTOGROUP
300 struct autogroup
*autogroup
;
303 struct cfs_bandwidth cfs_bandwidth
;
306 /* task_group_lock serializes the addition/removal of task groups */
307 static DEFINE_SPINLOCK(task_group_lock
);
309 #ifdef CONFIG_FAIR_GROUP_SCHED
311 # define ROOT_TASK_GROUP_LOAD NICE_0_LOAD
314 * A weight of 0 or 1 can cause arithmetics problems.
315 * A weight of a cfs_rq is the sum of weights of which entities
316 * are queued on this cfs_rq, so a weight of a entity should not be
317 * too large, so as the shares value of a task group.
318 * (The default weight is 1024 - so there's no practical
319 * limitation from this.)
321 #define MIN_SHARES (1UL << 1)
322 #define MAX_SHARES (1UL << 18)
324 static int root_task_group_load
= ROOT_TASK_GROUP_LOAD
;
327 /* Default task group.
328 * Every task in system belong to this group at bootup.
330 struct task_group root_task_group
;
332 #endif /* CONFIG_CGROUP_SCHED */
334 /* CFS-related fields in a runqueue */
336 struct load_weight load
;
337 unsigned long nr_running
, h_nr_running
;
342 u64 min_vruntime_copy
;
345 struct rb_root tasks_timeline
;
346 struct rb_node
*rb_leftmost
;
348 struct list_head tasks
;
349 struct list_head
*balance_iterator
;
352 * 'curr' points to currently running entity on this cfs_rq.
353 * It is set to NULL otherwise (i.e when none are currently running).
355 struct sched_entity
*curr
, *next
, *last
, *skip
;
357 #ifdef CONFIG_SCHED_DEBUG
358 unsigned int nr_spread_over
;
361 #ifdef CONFIG_FAIR_GROUP_SCHED
362 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
365 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
366 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
367 * (like users, containers etc.)
369 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
370 * list is used during load balance.
373 struct list_head leaf_cfs_rq_list
;
374 struct task_group
*tg
; /* group that "owns" this runqueue */
378 * the part of load.weight contributed by tasks
380 unsigned long task_weight
;
383 * h_load = weight * f(tg)
385 * Where f(tg) is the recursive weight fraction assigned to
388 unsigned long h_load
;
391 * Maintaining per-cpu shares distribution for group scheduling
393 * load_stamp is the last time we updated the load average
394 * load_last is the last time we updated the load average and saw load
395 * load_unacc_exec_time is currently unaccounted execution time
399 u64 load_stamp
, load_last
, load_unacc_exec_time
;
401 unsigned long load_contribution
;
403 #ifdef CONFIG_CFS_BANDWIDTH
406 s64 runtime_remaining
;
408 u64 throttled_timestamp
;
409 int throttled
, throttle_count
;
410 struct list_head throttled_list
;
415 #ifdef CONFIG_FAIR_GROUP_SCHED
416 #ifdef CONFIG_CFS_BANDWIDTH
417 static inline struct cfs_bandwidth
*tg_cfs_bandwidth(struct task_group
*tg
)
419 return &tg
->cfs_bandwidth
;
422 static inline u64
default_cfs_period(void);
423 static int do_sched_cfs_period_timer(struct cfs_bandwidth
*cfs_b
, int overrun
);
424 static void do_sched_cfs_slack_timer(struct cfs_bandwidth
*cfs_b
);
426 static enum hrtimer_restart
sched_cfs_slack_timer(struct hrtimer
*timer
)
428 struct cfs_bandwidth
*cfs_b
=
429 container_of(timer
, struct cfs_bandwidth
, slack_timer
);
430 do_sched_cfs_slack_timer(cfs_b
);
432 return HRTIMER_NORESTART
;
435 static enum hrtimer_restart
sched_cfs_period_timer(struct hrtimer
*timer
)
437 struct cfs_bandwidth
*cfs_b
=
438 container_of(timer
, struct cfs_bandwidth
, period_timer
);
444 now
= hrtimer_cb_get_time(timer
);
445 overrun
= hrtimer_forward(timer
, now
, cfs_b
->period
);
450 idle
= do_sched_cfs_period_timer(cfs_b
, overrun
);
453 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
456 static void init_cfs_bandwidth(struct cfs_bandwidth
*cfs_b
)
458 raw_spin_lock_init(&cfs_b
->lock
);
460 cfs_b
->quota
= RUNTIME_INF
;
461 cfs_b
->period
= ns_to_ktime(default_cfs_period());
463 INIT_LIST_HEAD(&cfs_b
->throttled_cfs_rq
);
464 hrtimer_init(&cfs_b
->period_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
465 cfs_b
->period_timer
.function
= sched_cfs_period_timer
;
466 hrtimer_init(&cfs_b
->slack_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
467 cfs_b
->slack_timer
.function
= sched_cfs_slack_timer
;
470 static void init_cfs_rq_runtime(struct cfs_rq
*cfs_rq
)
472 cfs_rq
->runtime_enabled
= 0;
473 INIT_LIST_HEAD(&cfs_rq
->throttled_list
);
476 /* requires cfs_b->lock, may release to reprogram timer */
477 static void __start_cfs_bandwidth(struct cfs_bandwidth
*cfs_b
)
480 * The timer may be active because we're trying to set a new bandwidth
481 * period or because we're racing with the tear-down path
482 * (timer_active==0 becomes visible before the hrtimer call-back
483 * terminates). In either case we ensure that it's re-programmed
485 while (unlikely(hrtimer_active(&cfs_b
->period_timer
))) {
486 raw_spin_unlock(&cfs_b
->lock
);
487 /* ensure cfs_b->lock is available while we wait */
488 hrtimer_cancel(&cfs_b
->period_timer
);
490 raw_spin_lock(&cfs_b
->lock
);
491 /* if someone else restarted the timer then we're done */
492 if (cfs_b
->timer_active
)
496 cfs_b
->timer_active
= 1;
497 start_bandwidth_timer(&cfs_b
->period_timer
, cfs_b
->period
);
500 static void destroy_cfs_bandwidth(struct cfs_bandwidth
*cfs_b
)
502 hrtimer_cancel(&cfs_b
->period_timer
);
503 hrtimer_cancel(&cfs_b
->slack_timer
);
506 static void init_cfs_rq_runtime(struct cfs_rq
*cfs_rq
) {}
507 static void init_cfs_bandwidth(struct cfs_bandwidth
*cfs_b
) {}
508 static void destroy_cfs_bandwidth(struct cfs_bandwidth
*cfs_b
) {}
510 static inline struct cfs_bandwidth
*tg_cfs_bandwidth(struct task_group
*tg
)
514 #endif /* CONFIG_CFS_BANDWIDTH */
515 #endif /* CONFIG_FAIR_GROUP_SCHED */
517 /* Real-Time classes' related field in a runqueue: */
519 struct rt_prio_array active
;
520 unsigned long rt_nr_running
;
521 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
523 int curr
; /* highest queued rt task prio */
525 int next
; /* next highest */
530 unsigned long rt_nr_migratory
;
531 unsigned long rt_nr_total
;
533 struct plist_head pushable_tasks
;
538 /* Nests inside the rq lock: */
539 raw_spinlock_t rt_runtime_lock
;
541 #ifdef CONFIG_RT_GROUP_SCHED
542 unsigned long rt_nr_boosted
;
545 struct list_head leaf_rt_rq_list
;
546 struct task_group
*tg
;
553 * We add the notion of a root-domain which will be used to define per-domain
554 * variables. Each exclusive cpuset essentially defines an island domain by
555 * fully partitioning the member cpus from any other cpuset. Whenever a new
556 * exclusive cpuset is created, we also create and attach a new root-domain
565 cpumask_var_t online
;
568 * The "RT overload" flag: it gets set if a CPU has more than
569 * one runnable RT task.
571 cpumask_var_t rto_mask
;
572 struct cpupri cpupri
;
576 * By default the system creates a single root-domain with all cpus as
577 * members (mimicking the global state we have today).
579 static struct root_domain def_root_domain
;
581 #endif /* CONFIG_SMP */
584 * This is the main, per-CPU runqueue data structure.
586 * Locking rule: those places that want to lock multiple runqueues
587 * (such as the load balancing or the thread migration code), lock
588 * acquire operations must be ordered by ascending &runqueue.
595 * nr_running and cpu_load should be in the same cacheline because
596 * remote CPUs use both these fields when doing load calculation.
598 unsigned long nr_running
;
599 #define CPU_LOAD_IDX_MAX 5
600 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
601 unsigned long last_load_update_tick
;
604 unsigned char nohz_balance_kick
;
606 int skip_clock_update
;
608 /* capture load from *all* tasks on this cpu: */
609 struct load_weight load
;
610 unsigned long nr_load_updates
;
616 #ifdef CONFIG_FAIR_GROUP_SCHED
617 /* list of leaf cfs_rq on this cpu: */
618 struct list_head leaf_cfs_rq_list
;
620 #ifdef CONFIG_RT_GROUP_SCHED
621 struct list_head leaf_rt_rq_list
;
625 * This is part of a global counter where only the total sum
626 * over all CPUs matters. A task can increase this counter on
627 * one CPU and if it got migrated afterwards it may decrease
628 * it on another CPU. Always updated under the runqueue lock:
630 unsigned long nr_uninterruptible
;
632 struct task_struct
*curr
, *idle
, *stop
;
633 unsigned long next_balance
;
634 struct mm_struct
*prev_mm
;
642 struct root_domain
*rd
;
643 struct sched_domain
*sd
;
645 unsigned long cpu_power
;
647 unsigned char idle_at_tick
;
648 /* For active balancing */
652 struct cpu_stop_work active_balance_work
;
653 /* cpu of this runqueue: */
663 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
666 #ifdef CONFIG_PARAVIRT
669 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
670 u64 prev_steal_time_rq
;
673 /* calc_load related fields */
674 unsigned long calc_load_update
;
675 long calc_load_active
;
677 #ifdef CONFIG_SCHED_HRTICK
679 int hrtick_csd_pending
;
680 struct call_single_data hrtick_csd
;
682 struct hrtimer hrtick_timer
;
685 #ifdef CONFIG_SCHEDSTATS
687 struct sched_info rq_sched_info
;
688 unsigned long long rq_cpu_time
;
689 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
691 /* sys_sched_yield() stats */
692 unsigned int yld_count
;
694 /* schedule() stats */
695 unsigned int sched_switch
;
696 unsigned int sched_count
;
697 unsigned int sched_goidle
;
699 /* try_to_wake_up() stats */
700 unsigned int ttwu_count
;
701 unsigned int ttwu_local
;
705 struct llist_head wake_list
;
709 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
712 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
);
714 static inline int cpu_of(struct rq
*rq
)
723 #define rcu_dereference_check_sched_domain(p) \
724 rcu_dereference_check((p), \
725 lockdep_is_held(&sched_domains_mutex))
728 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
729 * See detach_destroy_domains: synchronize_sched for details.
731 * The domain tree of any CPU may only be accessed from within
732 * preempt-disabled sections.
734 #define for_each_domain(cpu, __sd) \
735 for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
737 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
738 #define this_rq() (&__get_cpu_var(runqueues))
739 #define task_rq(p) cpu_rq(task_cpu(p))
740 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
741 #define raw_rq() (&__raw_get_cpu_var(runqueues))
743 #ifdef CONFIG_CGROUP_SCHED
746 * Return the group to which this tasks belongs.
748 * We use task_subsys_state_check() and extend the RCU verification with
749 * pi->lock and rq->lock because cpu_cgroup_attach() holds those locks for each
750 * task it moves into the cgroup. Therefore by holding either of those locks,
751 * we pin the task to the current cgroup.
753 static inline struct task_group
*task_group(struct task_struct
*p
)
755 struct task_group
*tg
;
756 struct cgroup_subsys_state
*css
;
758 css
= task_subsys_state_check(p
, cpu_cgroup_subsys_id
,
759 lockdep_is_held(&p
->pi_lock
) ||
760 lockdep_is_held(&task_rq(p
)->lock
));
761 tg
= container_of(css
, struct task_group
, css
);
763 return autogroup_task_group(p
, tg
);
766 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
767 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
769 #ifdef CONFIG_FAIR_GROUP_SCHED
770 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
771 p
->se
.parent
= task_group(p
)->se
[cpu
];
774 #ifdef CONFIG_RT_GROUP_SCHED
775 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
776 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
780 #else /* CONFIG_CGROUP_SCHED */
782 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
783 static inline struct task_group
*task_group(struct task_struct
*p
)
788 #endif /* CONFIG_CGROUP_SCHED */
790 static void update_rq_clock_task(struct rq
*rq
, s64 delta
);
792 static void update_rq_clock(struct rq
*rq
)
796 if (rq
->skip_clock_update
> 0)
799 delta
= sched_clock_cpu(cpu_of(rq
)) - rq
->clock
;
801 update_rq_clock_task(rq
, delta
);
805 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
807 #ifdef CONFIG_SCHED_DEBUG
808 # define const_debug __read_mostly
810 # define const_debug static const
814 * runqueue_is_locked - Returns true if the current cpu runqueue is locked
815 * @cpu: the processor in question.
817 * This interface allows printk to be called with the runqueue lock
818 * held and know whether or not it is OK to wake up the klogd.
820 int runqueue_is_locked(int cpu
)
822 return raw_spin_is_locked(&cpu_rq(cpu
)->lock
);
826 * Debugging: various feature bits
829 #define SCHED_FEAT(name, enabled) \
830 __SCHED_FEAT_##name ,
833 #include "sched_features.h"
838 #define SCHED_FEAT(name, enabled) \
839 (1UL << __SCHED_FEAT_##name) * enabled |
841 const_debug
unsigned int sysctl_sched_features
=
842 #include "sched_features.h"
847 #ifdef CONFIG_SCHED_DEBUG
848 #define SCHED_FEAT(name, enabled) \
851 static __read_mostly
char *sched_feat_names
[] = {
852 #include "sched_features.h"
858 static int sched_feat_show(struct seq_file
*m
, void *v
)
862 for (i
= 0; sched_feat_names
[i
]; i
++) {
863 if (!(sysctl_sched_features
& (1UL << i
)))
865 seq_printf(m
, "%s ", sched_feat_names
[i
]);
873 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
874 size_t cnt
, loff_t
*ppos
)
884 if (copy_from_user(&buf
, ubuf
, cnt
))
890 if (strncmp(cmp
, "NO_", 3) == 0) {
895 for (i
= 0; sched_feat_names
[i
]; i
++) {
896 if (strcmp(cmp
, sched_feat_names
[i
]) == 0) {
898 sysctl_sched_features
&= ~(1UL << i
);
900 sysctl_sched_features
|= (1UL << i
);
905 if (!sched_feat_names
[i
])
913 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
915 return single_open(filp
, sched_feat_show
, NULL
);
918 static const struct file_operations sched_feat_fops
= {
919 .open
= sched_feat_open
,
920 .write
= sched_feat_write
,
923 .release
= single_release
,
926 static __init
int sched_init_debug(void)
928 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
933 late_initcall(sched_init_debug
);
937 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
940 * Number of tasks to iterate in a single balance run.
941 * Limited because this is done with IRQs disabled.
943 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
946 * period over which we average the RT time consumption, measured
951 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
954 * period over which we measure -rt task cpu usage in us.
957 unsigned int sysctl_sched_rt_period
= 1000000;
959 static __read_mostly
int scheduler_running
;
962 * part of the period that we allow rt tasks to run in us.
965 int sysctl_sched_rt_runtime
= 950000;
967 static inline u64
global_rt_period(void)
969 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
972 static inline u64
global_rt_runtime(void)
974 if (sysctl_sched_rt_runtime
< 0)
977 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
980 #ifndef prepare_arch_switch
981 # define prepare_arch_switch(next) do { } while (0)
983 #ifndef finish_arch_switch
984 # define finish_arch_switch(prev) do { } while (0)
987 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
989 return rq
->curr
== p
;
992 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
997 return task_current(rq
, p
);
1001 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
1002 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
1006 * We can optimise this out completely for !SMP, because the
1007 * SMP rebalancing from interrupt is the only thing that cares
1014 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
1018 * After ->on_cpu is cleared, the task can be moved to a different CPU.
1019 * We must ensure this doesn't happen until the switch is completely
1025 #ifdef CONFIG_DEBUG_SPINLOCK
1026 /* this is a valid case when another task releases the spinlock */
1027 rq
->lock
.owner
= current
;
1030 * If we are tracking spinlock dependencies then we have to
1031 * fix up the runqueue lock - which gets 'carried over' from
1032 * prev into current:
1034 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
1036 raw_spin_unlock_irq(&rq
->lock
);
1039 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
1040 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
1044 * We can optimise this out completely for !SMP, because the
1045 * SMP rebalancing from interrupt is the only thing that cares
1050 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1051 raw_spin_unlock_irq(&rq
->lock
);
1053 raw_spin_unlock(&rq
->lock
);
1057 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
1061 * After ->on_cpu is cleared, the task can be moved to a different CPU.
1062 * We must ensure this doesn't happen until the switch is completely
1068 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1072 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
1075 * __task_rq_lock - lock the rq @p resides on.
1077 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
1078 __acquires(rq
->lock
)
1082 lockdep_assert_held(&p
->pi_lock
);
1086 raw_spin_lock(&rq
->lock
);
1087 if (likely(rq
== task_rq(p
)))
1089 raw_spin_unlock(&rq
->lock
);
1094 * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
1096 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
1097 __acquires(p
->pi_lock
)
1098 __acquires(rq
->lock
)
1103 raw_spin_lock_irqsave(&p
->pi_lock
, *flags
);
1105 raw_spin_lock(&rq
->lock
);
1106 if (likely(rq
== task_rq(p
)))
1108 raw_spin_unlock(&rq
->lock
);
1109 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
1113 static void __task_rq_unlock(struct rq
*rq
)
1114 __releases(rq
->lock
)
1116 raw_spin_unlock(&rq
->lock
);
1120 task_rq_unlock(struct rq
*rq
, struct task_struct
*p
, unsigned long *flags
)
1121 __releases(rq
->lock
)
1122 __releases(p
->pi_lock
)
1124 raw_spin_unlock(&rq
->lock
);
1125 raw_spin_unlock_irqrestore(&p
->pi_lock
, *flags
);
1129 * this_rq_lock - lock this runqueue and disable interrupts.
1131 static struct rq
*this_rq_lock(void)
1132 __acquires(rq
->lock
)
1136 local_irq_disable();
1138 raw_spin_lock(&rq
->lock
);
1143 #ifdef CONFIG_SCHED_HRTICK
1145 * Use HR-timers to deliver accurate preemption points.
1147 * Its all a bit involved since we cannot program an hrt while holding the
1148 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1151 * When we get rescheduled we reprogram the hrtick_timer outside of the
1157 * - enabled by features
1158 * - hrtimer is actually high res
1160 static inline int hrtick_enabled(struct rq
*rq
)
1162 if (!sched_feat(HRTICK
))
1164 if (!cpu_active(cpu_of(rq
)))
1166 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1169 static void hrtick_clear(struct rq
*rq
)
1171 if (hrtimer_active(&rq
->hrtick_timer
))
1172 hrtimer_cancel(&rq
->hrtick_timer
);
1176 * High-resolution timer tick.
1177 * Runs from hardirq context with interrupts disabled.
1179 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1181 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1183 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1185 raw_spin_lock(&rq
->lock
);
1186 update_rq_clock(rq
);
1187 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1188 raw_spin_unlock(&rq
->lock
);
1190 return HRTIMER_NORESTART
;
1195 * called from hardirq (IPI) context
1197 static void __hrtick_start(void *arg
)
1199 struct rq
*rq
= arg
;
1201 raw_spin_lock(&rq
->lock
);
1202 hrtimer_restart(&rq
->hrtick_timer
);
1203 rq
->hrtick_csd_pending
= 0;
1204 raw_spin_unlock(&rq
->lock
);
1208 * Called to set the hrtick timer state.
1210 * called with rq->lock held and irqs disabled
1212 static void hrtick_start(struct rq
*rq
, u64 delay
)
1214 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1215 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1217 hrtimer_set_expires(timer
, time
);
1219 if (rq
== this_rq()) {
1220 hrtimer_restart(timer
);
1221 } else if (!rq
->hrtick_csd_pending
) {
1222 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1223 rq
->hrtick_csd_pending
= 1;
1228 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1230 int cpu
= (int)(long)hcpu
;
1233 case CPU_UP_CANCELED
:
1234 case CPU_UP_CANCELED_FROZEN
:
1235 case CPU_DOWN_PREPARE
:
1236 case CPU_DOWN_PREPARE_FROZEN
:
1238 case CPU_DEAD_FROZEN
:
1239 hrtick_clear(cpu_rq(cpu
));
1246 static __init
void init_hrtick(void)
1248 hotcpu_notifier(hotplug_hrtick
, 0);
1252 * Called to set the hrtick timer state.
1254 * called with rq->lock held and irqs disabled
1256 static void hrtick_start(struct rq
*rq
, u64 delay
)
1258 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1259 HRTIMER_MODE_REL_PINNED
, 0);
1262 static inline void init_hrtick(void)
1265 #endif /* CONFIG_SMP */
1267 static void init_rq_hrtick(struct rq
*rq
)
1270 rq
->hrtick_csd_pending
= 0;
1272 rq
->hrtick_csd
.flags
= 0;
1273 rq
->hrtick_csd
.func
= __hrtick_start
;
1274 rq
->hrtick_csd
.info
= rq
;
1277 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1278 rq
->hrtick_timer
.function
= hrtick
;
1280 #else /* CONFIG_SCHED_HRTICK */
1281 static inline void hrtick_clear(struct rq
*rq
)
1285 static inline void init_rq_hrtick(struct rq
*rq
)
1289 static inline void init_hrtick(void)
1292 #endif /* CONFIG_SCHED_HRTICK */
1295 * resched_task - mark a task 'to be rescheduled now'.
1297 * On UP this means the setting of the need_resched flag, on SMP it
1298 * might also involve a cross-CPU call to trigger the scheduler on
1303 #ifndef tsk_is_polling
1304 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1307 static void resched_task(struct task_struct
*p
)
1311 assert_raw_spin_locked(&task_rq(p
)->lock
);
1313 if (test_tsk_need_resched(p
))
1316 set_tsk_need_resched(p
);
1319 if (cpu
== smp_processor_id())
1322 /* NEED_RESCHED must be visible before we test polling */
1324 if (!tsk_is_polling(p
))
1325 smp_send_reschedule(cpu
);
1328 static void resched_cpu(int cpu
)
1330 struct rq
*rq
= cpu_rq(cpu
);
1331 unsigned long flags
;
1333 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
1335 resched_task(cpu_curr(cpu
));
1336 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1341 * In the semi idle case, use the nearest busy cpu for migrating timers
1342 * from an idle cpu. This is good for power-savings.
1344 * We don't do similar optimization for completely idle system, as
1345 * selecting an idle cpu will add more delays to the timers than intended
1346 * (as that cpu's timer base may not be uptodate wrt jiffies etc).
1348 int get_nohz_timer_target(void)
1350 int cpu
= smp_processor_id();
1352 struct sched_domain
*sd
;
1355 for_each_domain(cpu
, sd
) {
1356 for_each_cpu(i
, sched_domain_span(sd
)) {
1368 * When add_timer_on() enqueues a timer into the timer wheel of an
1369 * idle CPU then this timer might expire before the next timer event
1370 * which is scheduled to wake up that CPU. In case of a completely
1371 * idle system the next event might even be infinite time into the
1372 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1373 * leaves the inner idle loop so the newly added timer is taken into
1374 * account when the CPU goes back to idle and evaluates the timer
1375 * wheel for the next timer event.
1377 void wake_up_idle_cpu(int cpu
)
1379 struct rq
*rq
= cpu_rq(cpu
);
1381 if (cpu
== smp_processor_id())
1385 * This is safe, as this function is called with the timer
1386 * wheel base lock of (cpu) held. When the CPU is on the way
1387 * to idle and has not yet set rq->curr to idle then it will
1388 * be serialized on the timer wheel base lock and take the new
1389 * timer into account automatically.
1391 if (rq
->curr
!= rq
->idle
)
1395 * We can set TIF_RESCHED on the idle task of the other CPU
1396 * lockless. The worst case is that the other CPU runs the
1397 * idle task through an additional NOOP schedule()
1399 set_tsk_need_resched(rq
->idle
);
1401 /* NEED_RESCHED must be visible before we test polling */
1403 if (!tsk_is_polling(rq
->idle
))
1404 smp_send_reschedule(cpu
);
1407 #endif /* CONFIG_NO_HZ */
1409 static u64
sched_avg_period(void)
1411 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1414 static void sched_avg_update(struct rq
*rq
)
1416 s64 period
= sched_avg_period();
1418 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1420 * Inline assembly required to prevent the compiler
1421 * optimising this loop into a divmod call.
1422 * See __iter_div_u64_rem() for another example of this.
1424 asm("" : "+rm" (rq
->age_stamp
));
1425 rq
->age_stamp
+= period
;
1430 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1432 rq
->rt_avg
+= rt_delta
;
1433 sched_avg_update(rq
);
1436 #else /* !CONFIG_SMP */
1437 static void resched_task(struct task_struct
*p
)
1439 assert_raw_spin_locked(&task_rq(p
)->lock
);
1440 set_tsk_need_resched(p
);
1443 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1447 static void sched_avg_update(struct rq
*rq
)
1450 #endif /* CONFIG_SMP */
1452 #if BITS_PER_LONG == 32
1453 # define WMULT_CONST (~0UL)
1455 # define WMULT_CONST (1UL << 32)
1458 #define WMULT_SHIFT 32
1461 * Shift right and round:
1463 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1466 * delta *= weight / lw
1468 static unsigned long
1469 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1470 struct load_weight
*lw
)
1475 * weight can be less than 2^SCHED_LOAD_RESOLUTION for task group sched
1476 * entities since MIN_SHARES = 2. Treat weight as 1 if less than
1477 * 2^SCHED_LOAD_RESOLUTION.
1479 if (likely(weight
> (1UL << SCHED_LOAD_RESOLUTION
)))
1480 tmp
= (u64
)delta_exec
* scale_load_down(weight
);
1482 tmp
= (u64
)delta_exec
;
1484 if (!lw
->inv_weight
) {
1485 unsigned long w
= scale_load_down(lw
->weight
);
1487 if (BITS_PER_LONG
> 32 && unlikely(w
>= WMULT_CONST
))
1489 else if (unlikely(!w
))
1490 lw
->inv_weight
= WMULT_CONST
;
1492 lw
->inv_weight
= WMULT_CONST
/ w
;
1496 * Check whether we'd overflow the 64-bit multiplication:
1498 if (unlikely(tmp
> WMULT_CONST
))
1499 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1502 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1504 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1507 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1513 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1519 static inline void update_load_set(struct load_weight
*lw
, unsigned long w
)
1526 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1527 * of tasks with abnormal "nice" values across CPUs the contribution that
1528 * each task makes to its run queue's load is weighted according to its
1529 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1530 * scaled version of the new time slice allocation that they receive on time
1534 #define WEIGHT_IDLEPRIO 3
1535 #define WMULT_IDLEPRIO 1431655765
1538 * Nice levels are multiplicative, with a gentle 10% change for every
1539 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1540 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1541 * that remained on nice 0.
1543 * The "10% effect" is relative and cumulative: from _any_ nice level,
1544 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1545 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1546 * If a task goes up by ~10% and another task goes down by ~10% then
1547 * the relative distance between them is ~25%.)
1549 static const int prio_to_weight
[40] = {
1550 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1551 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1552 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1553 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1554 /* 0 */ 1024, 820, 655, 526, 423,
1555 /* 5 */ 335, 272, 215, 172, 137,
1556 /* 10 */ 110, 87, 70, 56, 45,
1557 /* 15 */ 36, 29, 23, 18, 15,
1561 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1563 * In cases where the weight does not change often, we can use the
1564 * precalculated inverse to speed up arithmetics by turning divisions
1565 * into multiplications:
1567 static const u32 prio_to_wmult
[40] = {
1568 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1569 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1570 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1571 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1572 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1573 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1574 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1575 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1578 /* Time spent by the tasks of the cpu accounting group executing in ... */
1579 enum cpuacct_stat_index
{
1580 CPUACCT_STAT_USER
, /* ... user mode */
1581 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1583 CPUACCT_STAT_NSTATS
,
1586 #ifdef CONFIG_CGROUP_CPUACCT
1587 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1588 static void cpuacct_update_stats(struct task_struct
*tsk
,
1589 enum cpuacct_stat_index idx
, cputime_t val
);
1591 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1592 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1593 enum cpuacct_stat_index idx
, cputime_t val
) {}
1596 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1598 update_load_add(&rq
->load
, load
);
1601 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1603 update_load_sub(&rq
->load
, load
);
1606 #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \
1607 (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH)))
1608 typedef int (*tg_visitor
)(struct task_group
*, void *);
1611 * Iterate task_group tree rooted at *from, calling @down when first entering a
1612 * node and @up when leaving it for the final time.
1614 * Caller must hold rcu_lock or sufficient equivalent.
1616 static int walk_tg_tree_from(struct task_group
*from
,
1617 tg_visitor down
, tg_visitor up
, void *data
)
1619 struct task_group
*parent
, *child
;
1625 ret
= (*down
)(parent
, data
);
1628 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1635 ret
= (*up
)(parent
, data
);
1636 if (ret
|| parent
== from
)
1640 parent
= parent
->parent
;
1648 * Iterate the full tree, calling @down when first entering a node and @up when
1649 * leaving it for the final time.
1651 * Caller must hold rcu_lock or sufficient equivalent.
1654 static inline int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1656 return walk_tg_tree_from(&root_task_group
, down
, up
, data
);
1659 static int tg_nop(struct task_group
*tg
, void *data
)
1666 /* Used instead of source_load when we know the type == 0 */
1667 static unsigned long weighted_cpuload(const int cpu
)
1669 return cpu_rq(cpu
)->load
.weight
;
1673 * Return a low guess at the load of a migration-source cpu weighted
1674 * according to the scheduling class and "nice" value.
1676 * We want to under-estimate the load of migration sources, to
1677 * balance conservatively.
1679 static unsigned long source_load(int cpu
, int type
)
1681 struct rq
*rq
= cpu_rq(cpu
);
1682 unsigned long total
= weighted_cpuload(cpu
);
1684 if (type
== 0 || !sched_feat(LB_BIAS
))
1687 return min(rq
->cpu_load
[type
-1], total
);
1691 * Return a high guess at the load of a migration-target cpu weighted
1692 * according to the scheduling class and "nice" value.
1694 static unsigned long target_load(int cpu
, int type
)
1696 struct rq
*rq
= cpu_rq(cpu
);
1697 unsigned long total
= weighted_cpuload(cpu
);
1699 if (type
== 0 || !sched_feat(LB_BIAS
))
1702 return max(rq
->cpu_load
[type
-1], total
);
1705 static unsigned long power_of(int cpu
)
1707 return cpu_rq(cpu
)->cpu_power
;
1710 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1712 static unsigned long cpu_avg_load_per_task(int cpu
)
1714 struct rq
*rq
= cpu_rq(cpu
);
1715 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1718 return rq
->load
.weight
/ nr_running
;
1723 #ifdef CONFIG_PREEMPT
1725 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
1728 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1729 * way at the expense of forcing extra atomic operations in all
1730 * invocations. This assures that the double_lock is acquired using the
1731 * same underlying policy as the spinlock_t on this architecture, which
1732 * reduces latency compared to the unfair variant below. However, it
1733 * also adds more overhead and therefore may reduce throughput.
1735 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1736 __releases(this_rq
->lock
)
1737 __acquires(busiest
->lock
)
1738 __acquires(this_rq
->lock
)
1740 raw_spin_unlock(&this_rq
->lock
);
1741 double_rq_lock(this_rq
, busiest
);
1748 * Unfair double_lock_balance: Optimizes throughput at the expense of
1749 * latency by eliminating extra atomic operations when the locks are
1750 * already in proper order on entry. This favors lower cpu-ids and will
1751 * grant the double lock to lower cpus over higher ids under contention,
1752 * regardless of entry order into the function.
1754 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1755 __releases(this_rq
->lock
)
1756 __acquires(busiest
->lock
)
1757 __acquires(this_rq
->lock
)
1761 if (unlikely(!raw_spin_trylock(&busiest
->lock
))) {
1762 if (busiest
< this_rq
) {
1763 raw_spin_unlock(&this_rq
->lock
);
1764 raw_spin_lock(&busiest
->lock
);
1765 raw_spin_lock_nested(&this_rq
->lock
,
1766 SINGLE_DEPTH_NESTING
);
1769 raw_spin_lock_nested(&busiest
->lock
,
1770 SINGLE_DEPTH_NESTING
);
1775 #endif /* CONFIG_PREEMPT */
1778 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1780 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1782 if (unlikely(!irqs_disabled())) {
1783 /* printk() doesn't work good under rq->lock */
1784 raw_spin_unlock(&this_rq
->lock
);
1788 return _double_lock_balance(this_rq
, busiest
);
1791 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1792 __releases(busiest
->lock
)
1794 raw_spin_unlock(&busiest
->lock
);
1795 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1799 * double_rq_lock - safely lock two runqueues
1801 * Note this does not disable interrupts like task_rq_lock,
1802 * you need to do so manually before calling.
1804 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1805 __acquires(rq1
->lock
)
1806 __acquires(rq2
->lock
)
1808 BUG_ON(!irqs_disabled());
1810 raw_spin_lock(&rq1
->lock
);
1811 __acquire(rq2
->lock
); /* Fake it out ;) */
1814 raw_spin_lock(&rq1
->lock
);
1815 raw_spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
1817 raw_spin_lock(&rq2
->lock
);
1818 raw_spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
1824 * double_rq_unlock - safely unlock two runqueues
1826 * Note this does not restore interrupts like task_rq_unlock,
1827 * you need to do so manually after calling.
1829 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1830 __releases(rq1
->lock
)
1831 __releases(rq2
->lock
)
1833 raw_spin_unlock(&rq1
->lock
);
1835 raw_spin_unlock(&rq2
->lock
);
1837 __release(rq2
->lock
);
1840 #else /* CONFIG_SMP */
1843 * double_rq_lock - safely lock two runqueues
1845 * Note this does not disable interrupts like task_rq_lock,
1846 * you need to do so manually before calling.
1848 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1849 __acquires(rq1
->lock
)
1850 __acquires(rq2
->lock
)
1852 BUG_ON(!irqs_disabled());
1854 raw_spin_lock(&rq1
->lock
);
1855 __acquire(rq2
->lock
); /* Fake it out ;) */
1859 * double_rq_unlock - safely unlock two runqueues
1861 * Note this does not restore interrupts like task_rq_unlock,
1862 * you need to do so manually after calling.
1864 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1865 __releases(rq1
->lock
)
1866 __releases(rq2
->lock
)
1869 raw_spin_unlock(&rq1
->lock
);
1870 __release(rq2
->lock
);
1875 static void calc_load_account_idle(struct rq
*this_rq
);
1876 static void update_sysctl(void);
1877 static int get_update_sysctl_factor(void);
1878 static void update_cpu_load(struct rq
*this_rq
);
1880 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1882 set_task_rq(p
, cpu
);
1885 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1886 * successfuly executed on another CPU. We must ensure that updates of
1887 * per-task data have been completed by this moment.
1890 task_thread_info(p
)->cpu
= cpu
;
1894 static const struct sched_class rt_sched_class
;
1896 #define sched_class_highest (&stop_sched_class)
1897 #define for_each_class(class) \
1898 for (class = sched_class_highest; class; class = class->next)
1900 #include "sched_stats.h"
1902 static void inc_nr_running(struct rq
*rq
)
1907 static void dec_nr_running(struct rq
*rq
)
1912 static void set_load_weight(struct task_struct
*p
)
1914 int prio
= p
->static_prio
- MAX_RT_PRIO
;
1915 struct load_weight
*load
= &p
->se
.load
;
1918 * SCHED_IDLE tasks get minimal weight:
1920 if (p
->policy
== SCHED_IDLE
) {
1921 load
->weight
= scale_load(WEIGHT_IDLEPRIO
);
1922 load
->inv_weight
= WMULT_IDLEPRIO
;
1926 load
->weight
= scale_load(prio_to_weight
[prio
]);
1927 load
->inv_weight
= prio_to_wmult
[prio
];
1930 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1932 update_rq_clock(rq
);
1933 sched_info_queued(p
);
1934 p
->sched_class
->enqueue_task(rq
, p
, flags
);
1937 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1939 update_rq_clock(rq
);
1940 sched_info_dequeued(p
);
1941 p
->sched_class
->dequeue_task(rq
, p
, flags
);
1945 * activate_task - move a task to the runqueue.
1947 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1949 if (task_contributes_to_load(p
))
1950 rq
->nr_uninterruptible
--;
1952 enqueue_task(rq
, p
, flags
);
1956 * deactivate_task - remove a task from the runqueue.
1958 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int flags
)
1960 if (task_contributes_to_load(p
))
1961 rq
->nr_uninterruptible
++;
1963 dequeue_task(rq
, p
, flags
);
1966 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
1969 * There are no locks covering percpu hardirq/softirq time.
1970 * They are only modified in account_system_vtime, on corresponding CPU
1971 * with interrupts disabled. So, writes are safe.
1972 * They are read and saved off onto struct rq in update_rq_clock().
1973 * This may result in other CPU reading this CPU's irq time and can
1974 * race with irq/account_system_vtime on this CPU. We would either get old
1975 * or new value with a side effect of accounting a slice of irq time to wrong
1976 * task when irq is in progress while we read rq->clock. That is a worthy
1977 * compromise in place of having locks on each irq in account_system_time.
1979 static DEFINE_PER_CPU(u64
, cpu_hardirq_time
);
1980 static DEFINE_PER_CPU(u64
, cpu_softirq_time
);
1982 static DEFINE_PER_CPU(u64
, irq_start_time
);
1983 static int sched_clock_irqtime
;
1985 void enable_sched_clock_irqtime(void)
1987 sched_clock_irqtime
= 1;
1990 void disable_sched_clock_irqtime(void)
1992 sched_clock_irqtime
= 0;
1995 #ifndef CONFIG_64BIT
1996 static DEFINE_PER_CPU(seqcount_t
, irq_time_seq
);
1998 static inline void irq_time_write_begin(void)
2000 __this_cpu_inc(irq_time_seq
.sequence
);
2004 static inline void irq_time_write_end(void)
2007 __this_cpu_inc(irq_time_seq
.sequence
);
2010 static inline u64
irq_time_read(int cpu
)
2016 seq
= read_seqcount_begin(&per_cpu(irq_time_seq
, cpu
));
2017 irq_time
= per_cpu(cpu_softirq_time
, cpu
) +
2018 per_cpu(cpu_hardirq_time
, cpu
);
2019 } while (read_seqcount_retry(&per_cpu(irq_time_seq
, cpu
), seq
));
2023 #else /* CONFIG_64BIT */
2024 static inline void irq_time_write_begin(void)
2028 static inline void irq_time_write_end(void)
2032 static inline u64
irq_time_read(int cpu
)
2034 return per_cpu(cpu_softirq_time
, cpu
) + per_cpu(cpu_hardirq_time
, cpu
);
2036 #endif /* CONFIG_64BIT */
2039 * Called before incrementing preempt_count on {soft,}irq_enter
2040 * and before decrementing preempt_count on {soft,}irq_exit.
2042 void account_system_vtime(struct task_struct
*curr
)
2044 unsigned long flags
;
2048 if (!sched_clock_irqtime
)
2051 local_irq_save(flags
);
2053 cpu
= smp_processor_id();
2054 delta
= sched_clock_cpu(cpu
) - __this_cpu_read(irq_start_time
);
2055 __this_cpu_add(irq_start_time
, delta
);
2057 irq_time_write_begin();
2059 * We do not account for softirq time from ksoftirqd here.
2060 * We want to continue accounting softirq time to ksoftirqd thread
2061 * in that case, so as not to confuse scheduler with a special task
2062 * that do not consume any time, but still wants to run.
2064 if (hardirq_count())
2065 __this_cpu_add(cpu_hardirq_time
, delta
);
2066 else if (in_serving_softirq() && curr
!= this_cpu_ksoftirqd())
2067 __this_cpu_add(cpu_softirq_time
, delta
);
2069 irq_time_write_end();
2070 local_irq_restore(flags
);
2072 EXPORT_SYMBOL_GPL(account_system_vtime
);
2074 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
2076 #ifdef CONFIG_PARAVIRT
2077 static inline u64
steal_ticks(u64 steal
)
2079 if (unlikely(steal
> NSEC_PER_SEC
))
2080 return div_u64(steal
, TICK_NSEC
);
2082 return __iter_div_u64_rem(steal
, TICK_NSEC
, &steal
);
2086 static void update_rq_clock_task(struct rq
*rq
, s64 delta
)
2089 * In theory, the compile should just see 0 here, and optimize out the call
2090 * to sched_rt_avg_update. But I don't trust it...
2092 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
2093 s64 steal
= 0, irq_delta
= 0;
2095 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
2096 irq_delta
= irq_time_read(cpu_of(rq
)) - rq
->prev_irq_time
;
2099 * Since irq_time is only updated on {soft,}irq_exit, we might run into
2100 * this case when a previous update_rq_clock() happened inside a
2101 * {soft,}irq region.
2103 * When this happens, we stop ->clock_task and only update the
2104 * prev_irq_time stamp to account for the part that fit, so that a next
2105 * update will consume the rest. This ensures ->clock_task is
2108 * It does however cause some slight miss-attribution of {soft,}irq
2109 * time, a more accurate solution would be to update the irq_time using
2110 * the current rq->clock timestamp, except that would require using
2113 if (irq_delta
> delta
)
2116 rq
->prev_irq_time
+= irq_delta
;
2119 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
2120 if (static_branch((¶virt_steal_rq_enabled
))) {
2123 steal
= paravirt_steal_clock(cpu_of(rq
));
2124 steal
-= rq
->prev_steal_time_rq
;
2126 if (unlikely(steal
> delta
))
2129 st
= steal_ticks(steal
);
2130 steal
= st
* TICK_NSEC
;
2132 rq
->prev_steal_time_rq
+= steal
;
2138 rq
->clock_task
+= delta
;
2140 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
2141 if ((irq_delta
+ steal
) && sched_feat(NONTASK_POWER
))
2142 sched_rt_avg_update(rq
, irq_delta
+ steal
);
2146 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
2147 static int irqtime_account_hi_update(void)
2149 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
2150 unsigned long flags
;
2154 local_irq_save(flags
);
2155 latest_ns
= this_cpu_read(cpu_hardirq_time
);
2156 if (cputime64_gt(nsecs_to_cputime64(latest_ns
), cpustat
->irq
))
2158 local_irq_restore(flags
);
2162 static int irqtime_account_si_update(void)
2164 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
2165 unsigned long flags
;
2169 local_irq_save(flags
);
2170 latest_ns
= this_cpu_read(cpu_softirq_time
);
2171 if (cputime64_gt(nsecs_to_cputime64(latest_ns
), cpustat
->softirq
))
2173 local_irq_restore(flags
);
2177 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
2179 #define sched_clock_irqtime (0)
2183 #include "sched_idletask.c"
2184 #include "sched_fair.c"
2185 #include "sched_rt.c"
2186 #include "sched_autogroup.c"
2187 #include "sched_stoptask.c"
2188 #ifdef CONFIG_SCHED_DEBUG
2189 # include "sched_debug.c"
2192 void sched_set_stop_task(int cpu
, struct task_struct
*stop
)
2194 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
2195 struct task_struct
*old_stop
= cpu_rq(cpu
)->stop
;
2199 * Make it appear like a SCHED_FIFO task, its something
2200 * userspace knows about and won't get confused about.
2202 * Also, it will make PI more or less work without too
2203 * much confusion -- but then, stop work should not
2204 * rely on PI working anyway.
2206 sched_setscheduler_nocheck(stop
, SCHED_FIFO
, ¶m
);
2208 stop
->sched_class
= &stop_sched_class
;
2211 cpu_rq(cpu
)->stop
= stop
;
2215 * Reset it back to a normal scheduling class so that
2216 * it can die in pieces.
2218 old_stop
->sched_class
= &rt_sched_class
;
2223 * __normal_prio - return the priority that is based on the static prio
2225 static inline int __normal_prio(struct task_struct
*p
)
2227 return p
->static_prio
;
2231 * Calculate the expected normal priority: i.e. priority
2232 * without taking RT-inheritance into account. Might be
2233 * boosted by interactivity modifiers. Changes upon fork,
2234 * setprio syscalls, and whenever the interactivity
2235 * estimator recalculates.
2237 static inline int normal_prio(struct task_struct
*p
)
2241 if (task_has_rt_policy(p
))
2242 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
2244 prio
= __normal_prio(p
);
2249 * Calculate the current priority, i.e. the priority
2250 * taken into account by the scheduler. This value might
2251 * be boosted by RT tasks, or might be boosted by
2252 * interactivity modifiers. Will be RT if the task got
2253 * RT-boosted. If not then it returns p->normal_prio.
2255 static int effective_prio(struct task_struct
*p
)
2257 p
->normal_prio
= normal_prio(p
);
2259 * If we are RT tasks or we were boosted to RT priority,
2260 * keep the priority unchanged. Otherwise, update priority
2261 * to the normal priority:
2263 if (!rt_prio(p
->prio
))
2264 return p
->normal_prio
;
2269 * task_curr - is this task currently executing on a CPU?
2270 * @p: the task in question.
2272 inline int task_curr(const struct task_struct
*p
)
2274 return cpu_curr(task_cpu(p
)) == p
;
2277 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
2278 const struct sched_class
*prev_class
,
2281 if (prev_class
!= p
->sched_class
) {
2282 if (prev_class
->switched_from
)
2283 prev_class
->switched_from(rq
, p
);
2284 p
->sched_class
->switched_to(rq
, p
);
2285 } else if (oldprio
!= p
->prio
)
2286 p
->sched_class
->prio_changed(rq
, p
, oldprio
);
2289 static void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
2291 const struct sched_class
*class;
2293 if (p
->sched_class
== rq
->curr
->sched_class
) {
2294 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
2296 for_each_class(class) {
2297 if (class == rq
->curr
->sched_class
)
2299 if (class == p
->sched_class
) {
2300 resched_task(rq
->curr
);
2307 * A queue event has occurred, and we're going to schedule. In
2308 * this case, we can save a useless back to back clock update.
2310 if (rq
->curr
->on_rq
&& test_tsk_need_resched(rq
->curr
))
2311 rq
->skip_clock_update
= 1;
2316 * Is this task likely cache-hot:
2319 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2323 if (p
->sched_class
!= &fair_sched_class
)
2326 if (unlikely(p
->policy
== SCHED_IDLE
))
2330 * Buddy candidates are cache hot:
2332 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
2333 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
2334 &p
->se
== cfs_rq_of(&p
->se
)->last
))
2337 if (sysctl_sched_migration_cost
== -1)
2339 if (sysctl_sched_migration_cost
== 0)
2342 delta
= now
- p
->se
.exec_start
;
2344 return delta
< (s64
)sysctl_sched_migration_cost
;
2347 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2349 #ifdef CONFIG_SCHED_DEBUG
2351 * We should never call set_task_cpu() on a blocked task,
2352 * ttwu() will sort out the placement.
2354 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
2355 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
2357 #ifdef CONFIG_LOCKDEP
2359 * The caller should hold either p->pi_lock or rq->lock, when changing
2360 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
2362 * sched_move_task() holds both and thus holding either pins the cgroup,
2363 * see set_task_rq().
2365 * Furthermore, all task_rq users should acquire both locks, see
2368 WARN_ON_ONCE(debug_locks
&& !(lockdep_is_held(&p
->pi_lock
) ||
2369 lockdep_is_held(&task_rq(p
)->lock
)));
2373 trace_sched_migrate_task(p
, new_cpu
);
2375 if (task_cpu(p
) != new_cpu
) {
2376 p
->se
.nr_migrations
++;
2377 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, NULL
, 0);
2380 __set_task_cpu(p
, new_cpu
);
2383 struct migration_arg
{
2384 struct task_struct
*task
;
2388 static int migration_cpu_stop(void *data
);
2391 * wait_task_inactive - wait for a thread to unschedule.
2393 * If @match_state is nonzero, it's the @p->state value just checked and
2394 * not expected to change. If it changes, i.e. @p might have woken up,
2395 * then return zero. When we succeed in waiting for @p to be off its CPU,
2396 * we return a positive number (its total switch count). If a second call
2397 * a short while later returns the same number, the caller can be sure that
2398 * @p has remained unscheduled the whole time.
2400 * The caller must ensure that the task *will* unschedule sometime soon,
2401 * else this function might spin for a *long* time. This function can't
2402 * be called with interrupts off, or it may introduce deadlock with
2403 * smp_call_function() if an IPI is sent by the same process we are
2404 * waiting to become inactive.
2406 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2408 unsigned long flags
;
2415 * We do the initial early heuristics without holding
2416 * any task-queue locks at all. We'll only try to get
2417 * the runqueue lock when things look like they will
2423 * If the task is actively running on another CPU
2424 * still, just relax and busy-wait without holding
2427 * NOTE! Since we don't hold any locks, it's not
2428 * even sure that "rq" stays as the right runqueue!
2429 * But we don't care, since "task_running()" will
2430 * return false if the runqueue has changed and p
2431 * is actually now running somewhere else!
2433 while (task_running(rq
, p
)) {
2434 if (match_state
&& unlikely(p
->state
!= match_state
))
2440 * Ok, time to look more closely! We need the rq
2441 * lock now, to be *sure*. If we're wrong, we'll
2442 * just go back and repeat.
2444 rq
= task_rq_lock(p
, &flags
);
2445 trace_sched_wait_task(p
);
2446 running
= task_running(rq
, p
);
2449 if (!match_state
|| p
->state
== match_state
)
2450 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2451 task_rq_unlock(rq
, p
, &flags
);
2454 * If it changed from the expected state, bail out now.
2456 if (unlikely(!ncsw
))
2460 * Was it really running after all now that we
2461 * checked with the proper locks actually held?
2463 * Oops. Go back and try again..
2465 if (unlikely(running
)) {
2471 * It's not enough that it's not actively running,
2472 * it must be off the runqueue _entirely_, and not
2475 * So if it was still runnable (but just not actively
2476 * running right now), it's preempted, and we should
2477 * yield - it could be a while.
2479 if (unlikely(on_rq
)) {
2480 ktime_t to
= ktime_set(0, NSEC_PER_SEC
/HZ
);
2482 set_current_state(TASK_UNINTERRUPTIBLE
);
2483 schedule_hrtimeout(&to
, HRTIMER_MODE_REL
);
2488 * Ahh, all good. It wasn't running, and it wasn't
2489 * runnable, which means that it will never become
2490 * running in the future either. We're all done!
2499 * kick_process - kick a running thread to enter/exit the kernel
2500 * @p: the to-be-kicked thread
2502 * Cause a process which is running on another CPU to enter
2503 * kernel-mode, without any delay. (to get signals handled.)
2505 * NOTE: this function doesn't have to take the runqueue lock,
2506 * because all it wants to ensure is that the remote task enters
2507 * the kernel. If the IPI races and the task has been migrated
2508 * to another CPU then no harm is done and the purpose has been
2511 void kick_process(struct task_struct
*p
)
2517 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2518 smp_send_reschedule(cpu
);
2521 EXPORT_SYMBOL_GPL(kick_process
);
2522 #endif /* CONFIG_SMP */
2526 * ->cpus_allowed is protected by both rq->lock and p->pi_lock
2528 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
2531 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
2533 /* Look for allowed, online CPU in same node. */
2534 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
2535 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
2538 /* Any allowed, online CPU? */
2539 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
2540 if (dest_cpu
< nr_cpu_ids
)
2543 /* No more Mr. Nice Guy. */
2544 dest_cpu
= cpuset_cpus_allowed_fallback(p
);
2546 * Don't tell them about moving exiting tasks or
2547 * kernel threads (both mm NULL), since they never
2550 if (p
->mm
&& printk_ratelimit()) {
2551 printk(KERN_INFO
"process %d (%s) no longer affine to cpu%d\n",
2552 task_pid_nr(p
), p
->comm
, cpu
);
2559 * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable.
2562 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
2564 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
2567 * In order not to call set_task_cpu() on a blocking task we need
2568 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2571 * Since this is common to all placement strategies, this lives here.
2573 * [ this allows ->select_task() to simply return task_cpu(p) and
2574 * not worry about this generic constraint ]
2576 if (unlikely(!cpumask_test_cpu(cpu
, &p
->cpus_allowed
) ||
2578 cpu
= select_fallback_rq(task_cpu(p
), p
);
2583 static void update_avg(u64
*avg
, u64 sample
)
2585 s64 diff
= sample
- *avg
;
2591 ttwu_stat(struct task_struct
*p
, int cpu
, int wake_flags
)
2593 #ifdef CONFIG_SCHEDSTATS
2594 struct rq
*rq
= this_rq();
2597 int this_cpu
= smp_processor_id();
2599 if (cpu
== this_cpu
) {
2600 schedstat_inc(rq
, ttwu_local
);
2601 schedstat_inc(p
, se
.statistics
.nr_wakeups_local
);
2603 struct sched_domain
*sd
;
2605 schedstat_inc(p
, se
.statistics
.nr_wakeups_remote
);
2607 for_each_domain(this_cpu
, sd
) {
2608 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2609 schedstat_inc(sd
, ttwu_wake_remote
);
2616 if (wake_flags
& WF_MIGRATED
)
2617 schedstat_inc(p
, se
.statistics
.nr_wakeups_migrate
);
2619 #endif /* CONFIG_SMP */
2621 schedstat_inc(rq
, ttwu_count
);
2622 schedstat_inc(p
, se
.statistics
.nr_wakeups
);
2624 if (wake_flags
& WF_SYNC
)
2625 schedstat_inc(p
, se
.statistics
.nr_wakeups_sync
);
2627 #endif /* CONFIG_SCHEDSTATS */
2630 static void ttwu_activate(struct rq
*rq
, struct task_struct
*p
, int en_flags
)
2632 activate_task(rq
, p
, en_flags
);
2635 /* if a worker is waking up, notify workqueue */
2636 if (p
->flags
& PF_WQ_WORKER
)
2637 wq_worker_waking_up(p
, cpu_of(rq
));
2641 * Mark the task runnable and perform wakeup-preemption.
2644 ttwu_do_wakeup(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
2646 trace_sched_wakeup(p
, true);
2647 check_preempt_curr(rq
, p
, wake_flags
);
2649 p
->state
= TASK_RUNNING
;
2651 if (p
->sched_class
->task_woken
)
2652 p
->sched_class
->task_woken(rq
, p
);
2654 if (rq
->idle_stamp
) {
2655 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2656 u64 max
= 2*sysctl_sched_migration_cost
;
2661 update_avg(&rq
->avg_idle
, delta
);
2668 ttwu_do_activate(struct rq
*rq
, struct task_struct
*p
, int wake_flags
)
2671 if (p
->sched_contributes_to_load
)
2672 rq
->nr_uninterruptible
--;
2675 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
| ENQUEUE_WAKING
);
2676 ttwu_do_wakeup(rq
, p
, wake_flags
);
2680 * Called in case the task @p isn't fully descheduled from its runqueue,
2681 * in this case we must do a remote wakeup. Its a 'light' wakeup though,
2682 * since all we need to do is flip p->state to TASK_RUNNING, since
2683 * the task is still ->on_rq.
2685 static int ttwu_remote(struct task_struct
*p
, int wake_flags
)
2690 rq
= __task_rq_lock(p
);
2692 ttwu_do_wakeup(rq
, p
, wake_flags
);
2695 __task_rq_unlock(rq
);
2701 static void sched_ttwu_pending(void)
2703 struct rq
*rq
= this_rq();
2704 struct llist_node
*llist
= llist_del_all(&rq
->wake_list
);
2705 struct task_struct
*p
;
2707 raw_spin_lock(&rq
->lock
);
2710 p
= llist_entry(llist
, struct task_struct
, wake_entry
);
2711 llist
= llist_next(llist
);
2712 ttwu_do_activate(rq
, p
, 0);
2715 raw_spin_unlock(&rq
->lock
);
2718 void scheduler_ipi(void)
2720 if (llist_empty(&this_rq()->wake_list
))
2724 * Not all reschedule IPI handlers call irq_enter/irq_exit, since
2725 * traditionally all their work was done from the interrupt return
2726 * path. Now that we actually do some work, we need to make sure
2729 * Some archs already do call them, luckily irq_enter/exit nest
2732 * Arguably we should visit all archs and update all handlers,
2733 * however a fair share of IPIs are still resched only so this would
2734 * somewhat pessimize the simple resched case.
2737 sched_ttwu_pending();
2741 static void ttwu_queue_remote(struct task_struct
*p
, int cpu
)
2743 if (llist_add(&p
->wake_entry
, &cpu_rq(cpu
)->wake_list
))
2744 smp_send_reschedule(cpu
);
2747 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2748 static int ttwu_activate_remote(struct task_struct
*p
, int wake_flags
)
2753 rq
= __task_rq_lock(p
);
2755 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
2756 ttwu_do_wakeup(rq
, p
, wake_flags
);
2759 __task_rq_unlock(rq
);
2764 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
2765 #endif /* CONFIG_SMP */
2767 static void ttwu_queue(struct task_struct
*p
, int cpu
)
2769 struct rq
*rq
= cpu_rq(cpu
);
2771 #if defined(CONFIG_SMP)
2772 if (sched_feat(TTWU_QUEUE
) && cpu
!= smp_processor_id()) {
2773 sched_clock_cpu(cpu
); /* sync clocks x-cpu */
2774 ttwu_queue_remote(p
, cpu
);
2779 raw_spin_lock(&rq
->lock
);
2780 ttwu_do_activate(rq
, p
, 0);
2781 raw_spin_unlock(&rq
->lock
);
2785 * try_to_wake_up - wake up a thread
2786 * @p: the thread to be awakened
2787 * @state: the mask of task states that can be woken
2788 * @wake_flags: wake modifier flags (WF_*)
2790 * Put it on the run-queue if it's not already there. The "current"
2791 * thread is always on the run-queue (except when the actual
2792 * re-schedule is in progress), and as such you're allowed to do
2793 * the simpler "current->state = TASK_RUNNING" to mark yourself
2794 * runnable without the overhead of this.
2796 * Returns %true if @p was woken up, %false if it was already running
2797 * or @state didn't match @p's state.
2800 try_to_wake_up(struct task_struct
*p
, unsigned int state
, int wake_flags
)
2802 unsigned long flags
;
2803 int cpu
, success
= 0;
2806 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
2807 if (!(p
->state
& state
))
2810 success
= 1; /* we're going to change ->state */
2813 if (p
->on_rq
&& ttwu_remote(p
, wake_flags
))
2818 * If the owning (remote) cpu is still in the middle of schedule() with
2819 * this task as prev, wait until its done referencing the task.
2822 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
2824 * In case the architecture enables interrupts in
2825 * context_switch(), we cannot busy wait, since that
2826 * would lead to deadlocks when an interrupt hits and
2827 * tries to wake up @prev. So bail and do a complete
2830 if (ttwu_activate_remote(p
, wake_flags
))
2837 * Pairs with the smp_wmb() in finish_lock_switch().
2841 p
->sched_contributes_to_load
= !!task_contributes_to_load(p
);
2842 p
->state
= TASK_WAKING
;
2844 if (p
->sched_class
->task_waking
)
2845 p
->sched_class
->task_waking(p
);
2847 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
2848 if (task_cpu(p
) != cpu
) {
2849 wake_flags
|= WF_MIGRATED
;
2850 set_task_cpu(p
, cpu
);
2852 #endif /* CONFIG_SMP */
2856 ttwu_stat(p
, cpu
, wake_flags
);
2858 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
2864 * try_to_wake_up_local - try to wake up a local task with rq lock held
2865 * @p: the thread to be awakened
2867 * Put @p on the run-queue if it's not already there. The caller must
2868 * ensure that this_rq() is locked, @p is bound to this_rq() and not
2871 static void try_to_wake_up_local(struct task_struct
*p
)
2873 struct rq
*rq
= task_rq(p
);
2875 BUG_ON(rq
!= this_rq());
2876 BUG_ON(p
== current
);
2877 lockdep_assert_held(&rq
->lock
);
2879 if (!raw_spin_trylock(&p
->pi_lock
)) {
2880 raw_spin_unlock(&rq
->lock
);
2881 raw_spin_lock(&p
->pi_lock
);
2882 raw_spin_lock(&rq
->lock
);
2885 if (!(p
->state
& TASK_NORMAL
))
2889 ttwu_activate(rq
, p
, ENQUEUE_WAKEUP
);
2891 ttwu_do_wakeup(rq
, p
, 0);
2892 ttwu_stat(p
, smp_processor_id(), 0);
2894 raw_spin_unlock(&p
->pi_lock
);
2898 * wake_up_process - Wake up a specific process
2899 * @p: The process to be woken up.
2901 * Attempt to wake up the nominated process and move it to the set of runnable
2902 * processes. Returns 1 if the process was woken up, 0 if it was already
2905 * It may be assumed that this function implies a write memory barrier before
2906 * changing the task state if and only if any tasks are woken up.
2908 int wake_up_process(struct task_struct
*p
)
2910 return try_to_wake_up(p
, TASK_ALL
, 0);
2912 EXPORT_SYMBOL(wake_up_process
);
2914 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2916 return try_to_wake_up(p
, state
, 0);
2920 * Perform scheduler related setup for a newly forked process p.
2921 * p is forked by current.
2923 * __sched_fork() is basic setup used by init_idle() too:
2925 static void __sched_fork(struct task_struct
*p
)
2930 p
->se
.exec_start
= 0;
2931 p
->se
.sum_exec_runtime
= 0;
2932 p
->se
.prev_sum_exec_runtime
= 0;
2933 p
->se
.nr_migrations
= 0;
2935 INIT_LIST_HEAD(&p
->se
.group_node
);
2937 #ifdef CONFIG_SCHEDSTATS
2938 memset(&p
->se
.statistics
, 0, sizeof(p
->se
.statistics
));
2941 INIT_LIST_HEAD(&p
->rt
.run_list
);
2943 #ifdef CONFIG_PREEMPT_NOTIFIERS
2944 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2949 * fork()/clone()-time setup:
2951 void sched_fork(struct task_struct
*p
)
2953 unsigned long flags
;
2954 int cpu
= get_cpu();
2958 * We mark the process as running here. This guarantees that
2959 * nobody will actually run it, and a signal or other external
2960 * event cannot wake it up and insert it on the runqueue either.
2962 p
->state
= TASK_RUNNING
;
2965 * Make sure we do not leak PI boosting priority to the child.
2967 p
->prio
= current
->normal_prio
;
2970 * Revert to default priority/policy on fork if requested.
2972 if (unlikely(p
->sched_reset_on_fork
)) {
2973 if (task_has_rt_policy(p
)) {
2974 p
->policy
= SCHED_NORMAL
;
2975 p
->static_prio
= NICE_TO_PRIO(0);
2977 } else if (PRIO_TO_NICE(p
->static_prio
) < 0)
2978 p
->static_prio
= NICE_TO_PRIO(0);
2980 p
->prio
= p
->normal_prio
= __normal_prio(p
);
2984 * We don't need the reset flag anymore after the fork. It has
2985 * fulfilled its duty:
2987 p
->sched_reset_on_fork
= 0;
2990 if (!rt_prio(p
->prio
))
2991 p
->sched_class
= &fair_sched_class
;
2993 if (p
->sched_class
->task_fork
)
2994 p
->sched_class
->task_fork(p
);
2997 * The child is not yet in the pid-hash so no cgroup attach races,
2998 * and the cgroup is pinned to this child due to cgroup_fork()
2999 * is ran before sched_fork().
3001 * Silence PROVE_RCU.
3003 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
3004 set_task_cpu(p
, cpu
);
3005 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
3007 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
3008 if (likely(sched_info_on()))
3009 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
3011 #if defined(CONFIG_SMP)
3014 #ifdef CONFIG_PREEMPT_COUNT
3015 /* Want to start with kernel preemption disabled. */
3016 task_thread_info(p
)->preempt_count
= 1;
3019 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
3026 * wake_up_new_task - wake up a newly created task for the first time.
3028 * This function will do some initial scheduler statistics housekeeping
3029 * that must be done for every newly created context, then puts the task
3030 * on the runqueue and wakes it.
3032 void wake_up_new_task(struct task_struct
*p
)
3034 unsigned long flags
;
3037 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
3040 * Fork balancing, do it here and not earlier because:
3041 * - cpus_allowed can change in the fork path
3042 * - any previously selected cpu might disappear through hotplug
3044 set_task_cpu(p
, select_task_rq(p
, SD_BALANCE_FORK
, 0));
3047 rq
= __task_rq_lock(p
);
3048 activate_task(rq
, p
, 0);
3050 trace_sched_wakeup_new(p
, true);
3051 check_preempt_curr(rq
, p
, WF_FORK
);
3053 if (p
->sched_class
->task_woken
)
3054 p
->sched_class
->task_woken(rq
, p
);
3056 task_rq_unlock(rq
, p
, &flags
);
3059 #ifdef CONFIG_PREEMPT_NOTIFIERS
3062 * preempt_notifier_register - tell me when current is being preempted & rescheduled
3063 * @notifier: notifier struct to register
3065 void preempt_notifier_register(struct preempt_notifier
*notifier
)
3067 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
3069 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
3072 * preempt_notifier_unregister - no longer interested in preemption notifications
3073 * @notifier: notifier struct to unregister
3075 * This is safe to call from within a preemption notifier.
3077 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
3079 hlist_del(¬ifier
->link
);
3081 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
3083 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
3085 struct preempt_notifier
*notifier
;
3086 struct hlist_node
*node
;
3088 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
3089 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
3093 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
3094 struct task_struct
*next
)
3096 struct preempt_notifier
*notifier
;
3097 struct hlist_node
*node
;
3099 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
3100 notifier
->ops
->sched_out(notifier
, next
);
3103 #else /* !CONFIG_PREEMPT_NOTIFIERS */
3105 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
3110 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
3111 struct task_struct
*next
)
3115 #endif /* CONFIG_PREEMPT_NOTIFIERS */
3118 * prepare_task_switch - prepare to switch tasks
3119 * @rq: the runqueue preparing to switch
3120 * @prev: the current task that is being switched out
3121 * @next: the task we are going to switch to.
3123 * This is called with the rq lock held and interrupts off. It must
3124 * be paired with a subsequent finish_task_switch after the context
3127 * prepare_task_switch sets up locking and calls architecture specific
3131 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
3132 struct task_struct
*next
)
3134 sched_info_switch(prev
, next
);
3135 perf_event_task_sched_out(prev
, next
);
3136 fire_sched_out_preempt_notifiers(prev
, next
);
3137 prepare_lock_switch(rq
, next
);
3138 prepare_arch_switch(next
);
3139 trace_sched_switch(prev
, next
);
3143 * finish_task_switch - clean up after a task-switch
3144 * @rq: runqueue associated with task-switch
3145 * @prev: the thread we just switched away from.
3147 * finish_task_switch must be called after the context switch, paired
3148 * with a prepare_task_switch call before the context switch.
3149 * finish_task_switch will reconcile locking set up by prepare_task_switch,
3150 * and do any other architecture-specific cleanup actions.
3152 * Note that we may have delayed dropping an mm in context_switch(). If
3153 * so, we finish that here outside of the runqueue lock. (Doing it
3154 * with the lock held can cause deadlocks; see schedule() for
3157 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
3158 __releases(rq
->lock
)
3160 struct mm_struct
*mm
= rq
->prev_mm
;
3166 * A task struct has one reference for the use as "current".
3167 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
3168 * schedule one last time. The schedule call will never return, and
3169 * the scheduled task must drop that reference.
3170 * The test for TASK_DEAD must occur while the runqueue locks are
3171 * still held, otherwise prev could be scheduled on another cpu, die
3172 * there before we look at prev->state, and then the reference would
3174 * Manfred Spraul <manfred@colorfullife.com>
3176 prev_state
= prev
->state
;
3177 finish_arch_switch(prev
);
3178 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
3179 local_irq_disable();
3180 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
3181 perf_event_task_sched_in(prev
, current
);
3182 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
3184 #endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
3185 finish_lock_switch(rq
, prev
);
3187 fire_sched_in_preempt_notifiers(current
);
3190 if (unlikely(prev_state
== TASK_DEAD
)) {
3192 * Remove function-return probe instances associated with this
3193 * task and put them back on the free list.
3195 kprobe_flush_task(prev
);
3196 put_task_struct(prev
);
3202 /* assumes rq->lock is held */
3203 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
3205 if (prev
->sched_class
->pre_schedule
)
3206 prev
->sched_class
->pre_schedule(rq
, prev
);
3209 /* rq->lock is NOT held, but preemption is disabled */
3210 static inline void post_schedule(struct rq
*rq
)
3212 if (rq
->post_schedule
) {
3213 unsigned long flags
;
3215 raw_spin_lock_irqsave(&rq
->lock
, flags
);
3216 if (rq
->curr
->sched_class
->post_schedule
)
3217 rq
->curr
->sched_class
->post_schedule(rq
);
3218 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
3220 rq
->post_schedule
= 0;
3226 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
3230 static inline void post_schedule(struct rq
*rq
)
3237 * schedule_tail - first thing a freshly forked thread must call.
3238 * @prev: the thread we just switched away from.
3240 asmlinkage
void schedule_tail(struct task_struct
*prev
)
3241 __releases(rq
->lock
)
3243 struct rq
*rq
= this_rq();
3245 finish_task_switch(rq
, prev
);
3248 * FIXME: do we need to worry about rq being invalidated by the
3253 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
3254 /* In this case, finish_task_switch does not reenable preemption */
3257 if (current
->set_child_tid
)
3258 put_user(task_pid_vnr(current
), current
->set_child_tid
);
3262 * context_switch - switch to the new MM and the new
3263 * thread's register state.
3266 context_switch(struct rq
*rq
, struct task_struct
*prev
,
3267 struct task_struct
*next
)
3269 struct mm_struct
*mm
, *oldmm
;
3271 prepare_task_switch(rq
, prev
, next
);
3274 oldmm
= prev
->active_mm
;
3276 * For paravirt, this is coupled with an exit in switch_to to
3277 * combine the page table reload and the switch backend into
3280 arch_start_context_switch(prev
);
3283 next
->active_mm
= oldmm
;
3284 atomic_inc(&oldmm
->mm_count
);
3285 enter_lazy_tlb(oldmm
, next
);
3287 switch_mm(oldmm
, mm
, next
);
3290 prev
->active_mm
= NULL
;
3291 rq
->prev_mm
= oldmm
;
3294 * Since the runqueue lock will be released by the next
3295 * task (which is an invalid locking op but in the case
3296 * of the scheduler it's an obvious special-case), so we
3297 * do an early lockdep release here:
3299 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
3300 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
3303 /* Here we just switch the register state and the stack. */
3304 switch_to(prev
, next
, prev
);
3308 * this_rq must be evaluated again because prev may have moved
3309 * CPUs since it called schedule(), thus the 'rq' on its stack
3310 * frame will be invalid.
3312 finish_task_switch(this_rq(), prev
);
3316 * nr_running, nr_uninterruptible and nr_context_switches:
3318 * externally visible scheduler statistics: current number of runnable
3319 * threads, current number of uninterruptible-sleeping threads, total
3320 * number of context switches performed since bootup.
3322 unsigned long nr_running(void)
3324 unsigned long i
, sum
= 0;
3326 for_each_online_cpu(i
)
3327 sum
+= cpu_rq(i
)->nr_running
;
3332 unsigned long nr_uninterruptible(void)
3334 unsigned long i
, sum
= 0;
3336 for_each_possible_cpu(i
)
3337 sum
+= cpu_rq(i
)->nr_uninterruptible
;
3340 * Since we read the counters lockless, it might be slightly
3341 * inaccurate. Do not allow it to go below zero though:
3343 if (unlikely((long)sum
< 0))
3349 unsigned long long nr_context_switches(void)
3352 unsigned long long sum
= 0;
3354 for_each_possible_cpu(i
)
3355 sum
+= cpu_rq(i
)->nr_switches
;
3360 unsigned long nr_iowait(void)
3362 unsigned long i
, sum
= 0;
3364 for_each_possible_cpu(i
)
3365 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
3370 unsigned long nr_iowait_cpu(int cpu
)
3372 struct rq
*this = cpu_rq(cpu
);
3373 return atomic_read(&this->nr_iowait
);
3376 unsigned long this_cpu_load(void)
3378 struct rq
*this = this_rq();
3379 return this->cpu_load
[0];
3383 /* Variables and functions for calc_load */
3384 static atomic_long_t calc_load_tasks
;
3385 static unsigned long calc_load_update
;
3386 unsigned long avenrun
[3];
3387 EXPORT_SYMBOL(avenrun
);
3389 static long calc_load_fold_active(struct rq
*this_rq
)
3391 long nr_active
, delta
= 0;
3393 nr_active
= this_rq
->nr_running
;
3394 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3396 if (nr_active
!= this_rq
->calc_load_active
) {
3397 delta
= nr_active
- this_rq
->calc_load_active
;
3398 this_rq
->calc_load_active
= nr_active
;
3404 static unsigned long
3405 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
3408 load
+= active
* (FIXED_1
- exp
);
3409 load
+= 1UL << (FSHIFT
- 1);
3410 return load
>> FSHIFT
;
3415 * For NO_HZ we delay the active fold to the next LOAD_FREQ update.
3417 * When making the ILB scale, we should try to pull this in as well.
3419 static atomic_long_t calc_load_tasks_idle
;
3421 static void calc_load_account_idle(struct rq
*this_rq
)
3425 delta
= calc_load_fold_active(this_rq
);
3427 atomic_long_add(delta
, &calc_load_tasks_idle
);
3430 static long calc_load_fold_idle(void)
3435 * Its got a race, we don't care...
3437 if (atomic_long_read(&calc_load_tasks_idle
))
3438 delta
= atomic_long_xchg(&calc_load_tasks_idle
, 0);
3444 * fixed_power_int - compute: x^n, in O(log n) time
3446 * @x: base of the power
3447 * @frac_bits: fractional bits of @x
3448 * @n: power to raise @x to.
3450 * By exploiting the relation between the definition of the natural power
3451 * function: x^n := x*x*...*x (x multiplied by itself for n times), and
3452 * the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
3453 * (where: n_i \elem {0, 1}, the binary vector representing n),
3454 * we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
3455 * of course trivially computable in O(log_2 n), the length of our binary
3458 static unsigned long
3459 fixed_power_int(unsigned long x
, unsigned int frac_bits
, unsigned int n
)
3461 unsigned long result
= 1UL << frac_bits
;
3466 result
+= 1UL << (frac_bits
- 1);
3467 result
>>= frac_bits
;
3473 x
+= 1UL << (frac_bits
- 1);
3481 * a1 = a0 * e + a * (1 - e)
3483 * a2 = a1 * e + a * (1 - e)
3484 * = (a0 * e + a * (1 - e)) * e + a * (1 - e)
3485 * = a0 * e^2 + a * (1 - e) * (1 + e)
3487 * a3 = a2 * e + a * (1 - e)
3488 * = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
3489 * = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
3493 * an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
3494 * = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
3495 * = a0 * e^n + a * (1 - e^n)
3497 * [1] application of the geometric series:
3500 * S_n := \Sum x^i = -------------
3503 static unsigned long
3504 calc_load_n(unsigned long load
, unsigned long exp
,
3505 unsigned long active
, unsigned int n
)
3508 return calc_load(load
, fixed_power_int(exp
, FSHIFT
, n
), active
);
3512 * NO_HZ can leave us missing all per-cpu ticks calling
3513 * calc_load_account_active(), but since an idle CPU folds its delta into
3514 * calc_load_tasks_idle per calc_load_account_idle(), all we need to do is fold
3515 * in the pending idle delta if our idle period crossed a load cycle boundary.
3517 * Once we've updated the global active value, we need to apply the exponential
3518 * weights adjusted to the number of cycles missed.
3520 static void calc_global_nohz(unsigned long ticks
)
3522 long delta
, active
, n
;
3524 if (time_before(jiffies
, calc_load_update
))
3528 * If we crossed a calc_load_update boundary, make sure to fold
3529 * any pending idle changes, the respective CPUs might have
3530 * missed the tick driven calc_load_account_active() update
3533 delta
= calc_load_fold_idle();
3535 atomic_long_add(delta
, &calc_load_tasks
);
3538 * If we were idle for multiple load cycles, apply them.
3540 if (ticks
>= LOAD_FREQ
) {
3541 n
= ticks
/ LOAD_FREQ
;
3543 active
= atomic_long_read(&calc_load_tasks
);
3544 active
= active
> 0 ? active
* FIXED_1
: 0;
3546 avenrun
[0] = calc_load_n(avenrun
[0], EXP_1
, active
, n
);
3547 avenrun
[1] = calc_load_n(avenrun
[1], EXP_5
, active
, n
);
3548 avenrun
[2] = calc_load_n(avenrun
[2], EXP_15
, active
, n
);
3550 calc_load_update
+= n
* LOAD_FREQ
;
3554 * Its possible the remainder of the above division also crosses
3555 * a LOAD_FREQ period, the regular check in calc_global_load()
3556 * which comes after this will take care of that.
3558 * Consider us being 11 ticks before a cycle completion, and us
3559 * sleeping for 4*LOAD_FREQ + 22 ticks, then the above code will
3560 * age us 4 cycles, and the test in calc_global_load() will
3561 * pick up the final one.
3565 static void calc_load_account_idle(struct rq
*this_rq
)
3569 static inline long calc_load_fold_idle(void)
3574 static void calc_global_nohz(unsigned long ticks
)
3580 * get_avenrun - get the load average array
3581 * @loads: pointer to dest load array
3582 * @offset: offset to add
3583 * @shift: shift count to shift the result left
3585 * These values are estimates at best, so no need for locking.
3587 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
3589 loads
[0] = (avenrun
[0] + offset
) << shift
;
3590 loads
[1] = (avenrun
[1] + offset
) << shift
;
3591 loads
[2] = (avenrun
[2] + offset
) << shift
;
3595 * calc_load - update the avenrun load estimates 10 ticks after the
3596 * CPUs have updated calc_load_tasks.
3598 void calc_global_load(unsigned long ticks
)
3602 calc_global_nohz(ticks
);
3604 if (time_before(jiffies
, calc_load_update
+ 10))
3607 active
= atomic_long_read(&calc_load_tasks
);
3608 active
= active
> 0 ? active
* FIXED_1
: 0;
3610 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3611 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3612 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3614 calc_load_update
+= LOAD_FREQ
;
3618 * Called from update_cpu_load() to periodically update this CPU's
3621 static void calc_load_account_active(struct rq
*this_rq
)
3625 if (time_before(jiffies
, this_rq
->calc_load_update
))
3628 delta
= calc_load_fold_active(this_rq
);
3629 delta
+= calc_load_fold_idle();
3631 atomic_long_add(delta
, &calc_load_tasks
);
3633 this_rq
->calc_load_update
+= LOAD_FREQ
;
3637 * The exact cpuload at various idx values, calculated at every tick would be
3638 * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
3640 * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
3641 * on nth tick when cpu may be busy, then we have:
3642 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3643 * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
3645 * decay_load_missed() below does efficient calculation of
3646 * load = ((2^idx - 1) / 2^idx)^(n-1) * load
3647 * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
3649 * The calculation is approximated on a 128 point scale.
3650 * degrade_zero_ticks is the number of ticks after which load at any
3651 * particular idx is approximated to be zero.
3652 * degrade_factor is a precomputed table, a row for each load idx.
3653 * Each column corresponds to degradation factor for a power of two ticks,
3654 * based on 128 point scale.
3656 * row 2, col 3 (=12) says that the degradation at load idx 2 after
3657 * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
3659 * With this power of 2 load factors, we can degrade the load n times
3660 * by looking at 1 bits in n and doing as many mult/shift instead of
3661 * n mult/shifts needed by the exact degradation.
3663 #define DEGRADE_SHIFT 7
3664 static const unsigned char
3665 degrade_zero_ticks
[CPU_LOAD_IDX_MAX
] = {0, 8, 32, 64, 128};
3666 static const unsigned char
3667 degrade_factor
[CPU_LOAD_IDX_MAX
][DEGRADE_SHIFT
+ 1] = {
3668 {0, 0, 0, 0, 0, 0, 0, 0},
3669 {64, 32, 8, 0, 0, 0, 0, 0},
3670 {96, 72, 40, 12, 1, 0, 0},
3671 {112, 98, 75, 43, 15, 1, 0},
3672 {120, 112, 98, 76, 45, 16, 2} };
3675 * Update cpu_load for any missed ticks, due to tickless idle. The backlog
3676 * would be when CPU is idle and so we just decay the old load without
3677 * adding any new load.
3679 static unsigned long
3680 decay_load_missed(unsigned long load
, unsigned long missed_updates
, int idx
)
3684 if (!missed_updates
)
3687 if (missed_updates
>= degrade_zero_ticks
[idx
])
3691 return load
>> missed_updates
;
3693 while (missed_updates
) {
3694 if (missed_updates
% 2)
3695 load
= (load
* degrade_factor
[idx
][j
]) >> DEGRADE_SHIFT
;
3697 missed_updates
>>= 1;
3704 * Update rq->cpu_load[] statistics. This function is usually called every
3705 * scheduler tick (TICK_NSEC). With tickless idle this will not be called
3706 * every tick. We fix it up based on jiffies.
3708 static void update_cpu_load(struct rq
*this_rq
)
3710 unsigned long this_load
= this_rq
->load
.weight
;
3711 unsigned long curr_jiffies
= jiffies
;
3712 unsigned long pending_updates
;
3715 this_rq
->nr_load_updates
++;
3717 /* Avoid repeated calls on same jiffy, when moving in and out of idle */
3718 if (curr_jiffies
== this_rq
->last_load_update_tick
)
3721 pending_updates
= curr_jiffies
- this_rq
->last_load_update_tick
;
3722 this_rq
->last_load_update_tick
= curr_jiffies
;
3724 /* Update our load: */
3725 this_rq
->cpu_load
[0] = this_load
; /* Fasttrack for idx 0 */
3726 for (i
= 1, scale
= 2; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3727 unsigned long old_load
, new_load
;
3729 /* scale is effectively 1 << i now, and >> i divides by scale */
3731 old_load
= this_rq
->cpu_load
[i
];
3732 old_load
= decay_load_missed(old_load
, pending_updates
- 1, i
);
3733 new_load
= this_load
;
3735 * Round up the averaging division if load is increasing. This
3736 * prevents us from getting stuck on 9 if the load is 10, for
3739 if (new_load
> old_load
)
3740 new_load
+= scale
- 1;
3742 this_rq
->cpu_load
[i
] = (old_load
* (scale
- 1) + new_load
) >> i
;
3745 sched_avg_update(this_rq
);
3748 static void update_cpu_load_active(struct rq
*this_rq
)
3750 update_cpu_load(this_rq
);
3752 calc_load_account_active(this_rq
);
3758 * sched_exec - execve() is a valuable balancing opportunity, because at
3759 * this point the task has the smallest effective memory and cache footprint.
3761 void sched_exec(void)
3763 struct task_struct
*p
= current
;
3764 unsigned long flags
;
3767 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
3768 dest_cpu
= p
->sched_class
->select_task_rq(p
, SD_BALANCE_EXEC
, 0);
3769 if (dest_cpu
== smp_processor_id())
3772 if (likely(cpu_active(dest_cpu
))) {
3773 struct migration_arg arg
= { p
, dest_cpu
};
3775 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
3776 stop_one_cpu(task_cpu(p
), migration_cpu_stop
, &arg
);
3780 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
3785 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3787 EXPORT_PER_CPU_SYMBOL(kstat
);
3790 * Return any ns on the sched_clock that have not yet been accounted in
3791 * @p in case that task is currently running.
3793 * Called with task_rq_lock() held on @rq.
3795 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
3799 if (task_current(rq
, p
)) {
3800 update_rq_clock(rq
);
3801 ns
= rq
->clock_task
- p
->se
.exec_start
;
3809 unsigned long long task_delta_exec(struct task_struct
*p
)
3811 unsigned long flags
;
3815 rq
= task_rq_lock(p
, &flags
);
3816 ns
= do_task_delta_exec(p
, rq
);
3817 task_rq_unlock(rq
, p
, &flags
);
3823 * Return accounted runtime for the task.
3824 * In case the task is currently running, return the runtime plus current's
3825 * pending runtime that have not been accounted yet.
3827 unsigned long long task_sched_runtime(struct task_struct
*p
)
3829 unsigned long flags
;
3833 rq
= task_rq_lock(p
, &flags
);
3834 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3835 task_rq_unlock(rq
, p
, &flags
);
3841 * Account user cpu time to a process.
3842 * @p: the process that the cpu time gets accounted to
3843 * @cputime: the cpu time spent in user space since the last update
3844 * @cputime_scaled: cputime scaled by cpu frequency
3846 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
3847 cputime_t cputime_scaled
)
3849 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3852 /* Add user time to process. */
3853 p
->utime
= cputime_add(p
->utime
, cputime
);
3854 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3855 account_group_user_time(p
, cputime
);
3857 /* Add user time to cpustat. */
3858 tmp
= cputime_to_cputime64(cputime
);
3859 if (TASK_NICE(p
) > 0)
3860 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3862 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3864 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
3865 /* Account for user time used */
3866 acct_update_integrals(p
);
3870 * Account guest cpu time to a process.
3871 * @p: the process that the cpu time gets accounted to
3872 * @cputime: the cpu time spent in virtual machine since the last update
3873 * @cputime_scaled: cputime scaled by cpu frequency
3875 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
3876 cputime_t cputime_scaled
)
3879 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3881 tmp
= cputime_to_cputime64(cputime
);
3883 /* Add guest time to process. */
3884 p
->utime
= cputime_add(p
->utime
, cputime
);
3885 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3886 account_group_user_time(p
, cputime
);
3887 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3889 /* Add guest time to cpustat. */
3890 if (TASK_NICE(p
) > 0) {
3891 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3892 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
3894 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3895 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3900 * Account system cpu time to a process and desired cpustat field
3901 * @p: the process that the cpu time gets accounted to
3902 * @cputime: the cpu time spent in kernel space since the last update
3903 * @cputime_scaled: cputime scaled by cpu frequency
3904 * @target_cputime64: pointer to cpustat field that has to be updated
3907 void __account_system_time(struct task_struct
*p
, cputime_t cputime
,
3908 cputime_t cputime_scaled
, cputime64_t
*target_cputime64
)
3910 cputime64_t tmp
= cputime_to_cputime64(cputime
);
3912 /* Add system time to process. */
3913 p
->stime
= cputime_add(p
->stime
, cputime
);
3914 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
3915 account_group_system_time(p
, cputime
);
3917 /* Add system time to cpustat. */
3918 *target_cputime64
= cputime64_add(*target_cputime64
, tmp
);
3919 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
3921 /* Account for system time used */
3922 acct_update_integrals(p
);
3926 * Account system cpu time to a process.
3927 * @p: the process that the cpu time gets accounted to
3928 * @hardirq_offset: the offset to subtract from hardirq_count()
3929 * @cputime: the cpu time spent in kernel space since the last update
3930 * @cputime_scaled: cputime scaled by cpu frequency
3932 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3933 cputime_t cputime
, cputime_t cputime_scaled
)
3935 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3936 cputime64_t
*target_cputime64
;
3938 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3939 account_guest_time(p
, cputime
, cputime_scaled
);
3943 if (hardirq_count() - hardirq_offset
)
3944 target_cputime64
= &cpustat
->irq
;
3945 else if (in_serving_softirq())
3946 target_cputime64
= &cpustat
->softirq
;
3948 target_cputime64
= &cpustat
->system
;
3950 __account_system_time(p
, cputime
, cputime_scaled
, target_cputime64
);
3954 * Account for involuntary wait time.
3955 * @cputime: the cpu time spent in involuntary wait
3957 void account_steal_time(cputime_t cputime
)
3959 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3960 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3962 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
3966 * Account for idle time.
3967 * @cputime: the cpu time spent in idle wait
3969 void account_idle_time(cputime_t cputime
)
3971 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3972 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3973 struct rq
*rq
= this_rq();
3975 if (atomic_read(&rq
->nr_iowait
) > 0)
3976 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
3978 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
3981 static __always_inline
bool steal_account_process_tick(void)
3983 #ifdef CONFIG_PARAVIRT
3984 if (static_branch(¶virt_steal_enabled
)) {
3987 steal
= paravirt_steal_clock(smp_processor_id());
3988 steal
-= this_rq()->prev_steal_time
;
3990 st
= steal_ticks(steal
);
3991 this_rq()->prev_steal_time
+= st
* TICK_NSEC
;
3993 account_steal_time(st
);
4000 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4002 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
4004 * Account a tick to a process and cpustat
4005 * @p: the process that the cpu time gets accounted to
4006 * @user_tick: is the tick from userspace
4007 * @rq: the pointer to rq
4009 * Tick demultiplexing follows the order
4010 * - pending hardirq update
4011 * - pending softirq update
4015 * - check for guest_time
4016 * - else account as system_time
4018 * Check for hardirq is done both for system and user time as there is
4019 * no timer going off while we are on hardirq and hence we may never get an
4020 * opportunity to update it solely in system time.
4021 * p->stime and friends are only updated on system time and not on irq
4022 * softirq as those do not count in task exec_runtime any more.
4024 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
4027 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
4028 cputime64_t tmp
= cputime_to_cputime64(cputime_one_jiffy
);
4029 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4031 if (steal_account_process_tick())
4034 if (irqtime_account_hi_update()) {
4035 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
4036 } else if (irqtime_account_si_update()) {
4037 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
4038 } else if (this_cpu_ksoftirqd() == p
) {
4040 * ksoftirqd time do not get accounted in cpu_softirq_time.
4041 * So, we have to handle it separately here.
4042 * Also, p->stime needs to be updated for ksoftirqd.
4044 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
4046 } else if (user_tick
) {
4047 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
4048 } else if (p
== rq
->idle
) {
4049 account_idle_time(cputime_one_jiffy
);
4050 } else if (p
->flags
& PF_VCPU
) { /* System time or guest time */
4051 account_guest_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
4053 __account_system_time(p
, cputime_one_jiffy
, one_jiffy_scaled
,
4058 static void irqtime_account_idle_ticks(int ticks
)
4061 struct rq
*rq
= this_rq();
4063 for (i
= 0; i
< ticks
; i
++)
4064 irqtime_account_process_tick(current
, 0, rq
);
4066 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
4067 static void irqtime_account_idle_ticks(int ticks
) {}
4068 static void irqtime_account_process_tick(struct task_struct
*p
, int user_tick
,
4070 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
4073 * Account a single tick of cpu time.
4074 * @p: the process that the cpu time gets accounted to
4075 * @user_tick: indicates if the tick is a user or a system tick
4077 void account_process_tick(struct task_struct
*p
, int user_tick
)
4079 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
4080 struct rq
*rq
= this_rq();
4082 if (sched_clock_irqtime
) {
4083 irqtime_account_process_tick(p
, user_tick
, rq
);
4087 if (steal_account_process_tick())
4091 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
4092 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
4093 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
4096 account_idle_time(cputime_one_jiffy
);
4100 * Account multiple ticks of steal time.
4101 * @p: the process from which the cpu time has been stolen
4102 * @ticks: number of stolen ticks
4104 void account_steal_ticks(unsigned long ticks
)
4106 account_steal_time(jiffies_to_cputime(ticks
));
4110 * Account multiple ticks of idle time.
4111 * @ticks: number of stolen ticks
4113 void account_idle_ticks(unsigned long ticks
)
4116 if (sched_clock_irqtime
) {
4117 irqtime_account_idle_ticks(ticks
);
4121 account_idle_time(jiffies_to_cputime(ticks
));
4127 * Use precise platform statistics if available:
4129 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4130 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
4136 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
4138 struct task_cputime cputime
;
4140 thread_group_cputime(p
, &cputime
);
4142 *ut
= cputime
.utime
;
4143 *st
= cputime
.stime
;
4147 #ifndef nsecs_to_cputime
4148 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
4151 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
4153 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
4156 * Use CFS's precise accounting:
4158 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
4164 do_div(temp
, total
);
4165 utime
= (cputime_t
)temp
;
4170 * Compare with previous values, to keep monotonicity:
4172 p
->prev_utime
= max(p
->prev_utime
, utime
);
4173 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
4175 *ut
= p
->prev_utime
;
4176 *st
= p
->prev_stime
;
4180 * Must be called with siglock held.
4182 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
4184 struct signal_struct
*sig
= p
->signal
;
4185 struct task_cputime cputime
;
4186 cputime_t rtime
, utime
, total
;
4188 thread_group_cputime(p
, &cputime
);
4190 total
= cputime_add(cputime
.utime
, cputime
.stime
);
4191 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
4196 temp
*= cputime
.utime
;
4197 do_div(temp
, total
);
4198 utime
= (cputime_t
)temp
;
4202 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
4203 sig
->prev_stime
= max(sig
->prev_stime
,
4204 cputime_sub(rtime
, sig
->prev_utime
));
4206 *ut
= sig
->prev_utime
;
4207 *st
= sig
->prev_stime
;
4212 * This function gets called by the timer code, with HZ frequency.
4213 * We call it with interrupts disabled.
4215 void scheduler_tick(void)
4217 int cpu
= smp_processor_id();
4218 struct rq
*rq
= cpu_rq(cpu
);
4219 struct task_struct
*curr
= rq
->curr
;
4223 raw_spin_lock(&rq
->lock
);
4224 update_rq_clock(rq
);
4225 update_cpu_load_active(rq
);
4226 curr
->sched_class
->task_tick(rq
, curr
, 0);
4227 raw_spin_unlock(&rq
->lock
);
4229 perf_event_task_tick();
4232 rq
->idle_at_tick
= idle_cpu(cpu
);
4233 trigger_load_balance(rq
, cpu
);
4237 notrace
unsigned long get_parent_ip(unsigned long addr
)
4239 if (in_lock_functions(addr
)) {
4240 addr
= CALLER_ADDR2
;
4241 if (in_lock_functions(addr
))
4242 addr
= CALLER_ADDR3
;
4247 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4248 defined(CONFIG_PREEMPT_TRACER))
4250 void __kprobes
add_preempt_count(int val
)
4252 #ifdef CONFIG_DEBUG_PREEMPT
4256 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4259 preempt_count() += val
;
4260 #ifdef CONFIG_DEBUG_PREEMPT
4262 * Spinlock count overflowing soon?
4264 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4267 if (preempt_count() == val
)
4268 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4270 EXPORT_SYMBOL(add_preempt_count
);
4272 void __kprobes
sub_preempt_count(int val
)
4274 #ifdef CONFIG_DEBUG_PREEMPT
4278 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
4281 * Is the spinlock portion underflowing?
4283 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4284 !(preempt_count() & PREEMPT_MASK
)))
4288 if (preempt_count() == val
)
4289 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4290 preempt_count() -= val
;
4292 EXPORT_SYMBOL(sub_preempt_count
);
4297 * Print scheduling while atomic bug:
4299 static noinline
void __schedule_bug(struct task_struct
*prev
)
4301 struct pt_regs
*regs
= get_irq_regs();
4303 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4304 prev
->comm
, prev
->pid
, preempt_count());
4306 debug_show_held_locks(prev
);
4308 if (irqs_disabled())
4309 print_irqtrace_events(prev
);
4318 * Various schedule()-time debugging checks and statistics:
4320 static inline void schedule_debug(struct task_struct
*prev
)
4323 * Test if we are atomic. Since do_exit() needs to call into
4324 * schedule() atomically, we ignore that path for now.
4325 * Otherwise, whine if we are scheduling when we should not be.
4327 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4328 __schedule_bug(prev
);
4330 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4332 schedstat_inc(this_rq(), sched_count
);
4335 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
4337 if (prev
->on_rq
|| rq
->skip_clock_update
< 0)
4338 update_rq_clock(rq
);
4339 prev
->sched_class
->put_prev_task(rq
, prev
);
4343 * Pick up the highest-prio task:
4345 static inline struct task_struct
*
4346 pick_next_task(struct rq
*rq
)
4348 const struct sched_class
*class;
4349 struct task_struct
*p
;
4352 * Optimization: we know that if all tasks are in
4353 * the fair class we can call that function directly:
4355 if (likely(rq
->nr_running
== rq
->cfs
.h_nr_running
)) {
4356 p
= fair_sched_class
.pick_next_task(rq
);
4361 for_each_class(class) {
4362 p
= class->pick_next_task(rq
);
4367 BUG(); /* the idle class will always have a runnable task */
4371 * __schedule() is the main scheduler function.
4373 static void __sched
__schedule(void)
4375 struct task_struct
*prev
, *next
;
4376 unsigned long *switch_count
;
4382 cpu
= smp_processor_id();
4384 rcu_note_context_switch(cpu
);
4387 schedule_debug(prev
);
4389 if (sched_feat(HRTICK
))
4392 raw_spin_lock_irq(&rq
->lock
);
4394 switch_count
= &prev
->nivcsw
;
4395 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4396 if (unlikely(signal_pending_state(prev
->state
, prev
))) {
4397 prev
->state
= TASK_RUNNING
;
4399 deactivate_task(rq
, prev
, DEQUEUE_SLEEP
);
4403 * If a worker went to sleep, notify and ask workqueue
4404 * whether it wants to wake up a task to maintain
4407 if (prev
->flags
& PF_WQ_WORKER
) {
4408 struct task_struct
*to_wakeup
;
4410 to_wakeup
= wq_worker_sleeping(prev
, cpu
);
4412 try_to_wake_up_local(to_wakeup
);
4415 switch_count
= &prev
->nvcsw
;
4418 pre_schedule(rq
, prev
);
4420 if (unlikely(!rq
->nr_running
))
4421 idle_balance(cpu
, rq
);
4423 put_prev_task(rq
, prev
);
4424 next
= pick_next_task(rq
);
4425 clear_tsk_need_resched(prev
);
4426 rq
->skip_clock_update
= 0;
4428 if (likely(prev
!= next
)) {
4433 context_switch(rq
, prev
, next
); /* unlocks the rq */
4435 * The context switch have flipped the stack from under us
4436 * and restored the local variables which were saved when
4437 * this task called schedule() in the past. prev == current
4438 * is still correct, but it can be moved to another cpu/rq.
4440 cpu
= smp_processor_id();
4443 raw_spin_unlock_irq(&rq
->lock
);
4447 preempt_enable_no_resched();
4452 static inline void sched_submit_work(struct task_struct
*tsk
)
4457 * If we are going to sleep and we have plugged IO queued,
4458 * make sure to submit it to avoid deadlocks.
4460 if (blk_needs_flush_plug(tsk
))
4461 blk_schedule_flush_plug(tsk
);
4464 asmlinkage
void __sched
schedule(void)
4466 struct task_struct
*tsk
= current
;
4468 sched_submit_work(tsk
);
4471 EXPORT_SYMBOL(schedule
);
4473 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
4475 static inline bool owner_running(struct mutex
*lock
, struct task_struct
*owner
)
4477 if (lock
->owner
!= owner
)
4481 * Ensure we emit the owner->on_cpu, dereference _after_ checking
4482 * lock->owner still matches owner, if that fails, owner might
4483 * point to free()d memory, if it still matches, the rcu_read_lock()
4484 * ensures the memory stays valid.
4488 return owner
->on_cpu
;
4492 * Look out! "owner" is an entirely speculative pointer
4493 * access and not reliable.
4495 int mutex_spin_on_owner(struct mutex
*lock
, struct task_struct
*owner
)
4497 if (!sched_feat(OWNER_SPIN
))
4501 while (owner_running(lock
, owner
)) {
4505 arch_mutex_cpu_relax();
4510 * We break out the loop above on need_resched() and when the
4511 * owner changed, which is a sign for heavy contention. Return
4512 * success only when lock->owner is NULL.
4514 return lock
->owner
== NULL
;
4518 #ifdef CONFIG_PREEMPT
4520 * this is the entry point to schedule() from in-kernel preemption
4521 * off of preempt_enable. Kernel preemptions off return from interrupt
4522 * occur there and call schedule directly.
4524 asmlinkage
void __sched notrace
preempt_schedule(void)
4526 struct thread_info
*ti
= current_thread_info();
4529 * If there is a non-zero preempt_count or interrupts are disabled,
4530 * we do not want to preempt the current task. Just return..
4532 if (likely(ti
->preempt_count
|| irqs_disabled()))
4536 add_preempt_count_notrace(PREEMPT_ACTIVE
);
4538 sub_preempt_count_notrace(PREEMPT_ACTIVE
);
4541 * Check again in case we missed a preemption opportunity
4542 * between schedule and now.
4545 } while (need_resched());
4547 EXPORT_SYMBOL(preempt_schedule
);
4550 * this is the entry point to schedule() from kernel preemption
4551 * off of irq context.
4552 * Note, that this is called and return with irqs disabled. This will
4553 * protect us against recursive calling from irq.
4555 asmlinkage
void __sched
preempt_schedule_irq(void)
4557 struct thread_info
*ti
= current_thread_info();
4559 /* Catch callers which need to be fixed */
4560 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4563 add_preempt_count(PREEMPT_ACTIVE
);
4566 local_irq_disable();
4567 sub_preempt_count(PREEMPT_ACTIVE
);
4570 * Check again in case we missed a preemption opportunity
4571 * between schedule and now.
4574 } while (need_resched());
4577 #endif /* CONFIG_PREEMPT */
4579 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
4582 return try_to_wake_up(curr
->private, mode
, wake_flags
);
4584 EXPORT_SYMBOL(default_wake_function
);
4587 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4588 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4589 * number) then we wake all the non-exclusive tasks and one exclusive task.
4591 * There are circumstances in which we can try to wake a task which has already
4592 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4593 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4595 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4596 int nr_exclusive
, int wake_flags
, void *key
)
4598 wait_queue_t
*curr
, *next
;
4600 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4601 unsigned flags
= curr
->flags
;
4603 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
4604 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4610 * __wake_up - wake up threads blocked on a waitqueue.
4612 * @mode: which threads
4613 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4614 * @key: is directly passed to the wakeup function
4616 * It may be assumed that this function implies a write memory barrier before
4617 * changing the task state if and only if any tasks are woken up.
4619 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4620 int nr_exclusive
, void *key
)
4622 unsigned long flags
;
4624 spin_lock_irqsave(&q
->lock
, flags
);
4625 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4626 spin_unlock_irqrestore(&q
->lock
, flags
);
4628 EXPORT_SYMBOL(__wake_up
);
4631 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4633 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4635 __wake_up_common(q
, mode
, 1, 0, NULL
);
4637 EXPORT_SYMBOL_GPL(__wake_up_locked
);
4639 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
4641 __wake_up_common(q
, mode
, 1, 0, key
);
4643 EXPORT_SYMBOL_GPL(__wake_up_locked_key
);
4646 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
4648 * @mode: which threads
4649 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4650 * @key: opaque value to be passed to wakeup targets
4652 * The sync wakeup differs that the waker knows that it will schedule
4653 * away soon, so while the target thread will be woken up, it will not
4654 * be migrated to another CPU - ie. the two threads are 'synchronized'
4655 * with each other. This can prevent needless bouncing between CPUs.
4657 * On UP it can prevent extra preemption.
4659 * It may be assumed that this function implies a write memory barrier before
4660 * changing the task state if and only if any tasks are woken up.
4662 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
4663 int nr_exclusive
, void *key
)
4665 unsigned long flags
;
4666 int wake_flags
= WF_SYNC
;
4671 if (unlikely(!nr_exclusive
))
4674 spin_lock_irqsave(&q
->lock
, flags
);
4675 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
4676 spin_unlock_irqrestore(&q
->lock
, flags
);
4678 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
4681 * __wake_up_sync - see __wake_up_sync_key()
4683 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4685 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
4687 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4690 * complete: - signals a single thread waiting on this completion
4691 * @x: holds the state of this particular completion
4693 * This will wake up a single thread waiting on this completion. Threads will be
4694 * awakened in the same order in which they were queued.
4696 * See also complete_all(), wait_for_completion() and related routines.
4698 * It may be assumed that this function implies a write memory barrier before
4699 * changing the task state if and only if any tasks are woken up.
4701 void complete(struct completion
*x
)
4703 unsigned long flags
;
4705 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4707 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4708 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4710 EXPORT_SYMBOL(complete
);
4713 * complete_all: - signals all threads waiting on this completion
4714 * @x: holds the state of this particular completion
4716 * This will wake up all threads waiting on this particular completion event.
4718 * It may be assumed that this function implies a write memory barrier before
4719 * changing the task state if and only if any tasks are woken up.
4721 void complete_all(struct completion
*x
)
4723 unsigned long flags
;
4725 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4726 x
->done
+= UINT_MAX
/2;
4727 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4728 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4730 EXPORT_SYMBOL(complete_all
);
4732 static inline long __sched
4733 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4736 DECLARE_WAITQUEUE(wait
, current
);
4738 __add_wait_queue_tail_exclusive(&x
->wait
, &wait
);
4740 if (signal_pending_state(state
, current
)) {
4741 timeout
= -ERESTARTSYS
;
4744 __set_current_state(state
);
4745 spin_unlock_irq(&x
->wait
.lock
);
4746 timeout
= schedule_timeout(timeout
);
4747 spin_lock_irq(&x
->wait
.lock
);
4748 } while (!x
->done
&& timeout
);
4749 __remove_wait_queue(&x
->wait
, &wait
);
4754 return timeout
?: 1;
4758 wait_for_common(struct completion
*x
, long timeout
, int state
)
4762 spin_lock_irq(&x
->wait
.lock
);
4763 timeout
= do_wait_for_common(x
, timeout
, state
);
4764 spin_unlock_irq(&x
->wait
.lock
);
4769 * wait_for_completion: - waits for completion of a task
4770 * @x: holds the state of this particular completion
4772 * This waits to be signaled for completion of a specific task. It is NOT
4773 * interruptible and there is no timeout.
4775 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4776 * and interrupt capability. Also see complete().
4778 void __sched
wait_for_completion(struct completion
*x
)
4780 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4782 EXPORT_SYMBOL(wait_for_completion
);
4785 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4786 * @x: holds the state of this particular completion
4787 * @timeout: timeout value in jiffies
4789 * This waits for either a completion of a specific task to be signaled or for a
4790 * specified timeout to expire. The timeout is in jiffies. It is not
4793 unsigned long __sched
4794 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4796 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4798 EXPORT_SYMBOL(wait_for_completion_timeout
);
4801 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4802 * @x: holds the state of this particular completion
4804 * This waits for completion of a specific task to be signaled. It is
4807 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4809 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4810 if (t
== -ERESTARTSYS
)
4814 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4817 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4818 * @x: holds the state of this particular completion
4819 * @timeout: timeout value in jiffies
4821 * This waits for either a completion of a specific task to be signaled or for a
4822 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4825 wait_for_completion_interruptible_timeout(struct completion
*x
,
4826 unsigned long timeout
)
4828 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4830 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4833 * wait_for_completion_killable: - waits for completion of a task (killable)
4834 * @x: holds the state of this particular completion
4836 * This waits to be signaled for completion of a specific task. It can be
4837 * interrupted by a kill signal.
4839 int __sched
wait_for_completion_killable(struct completion
*x
)
4841 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4842 if (t
== -ERESTARTSYS
)
4846 EXPORT_SYMBOL(wait_for_completion_killable
);
4849 * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
4850 * @x: holds the state of this particular completion
4851 * @timeout: timeout value in jiffies
4853 * This waits for either a completion of a specific task to be
4854 * signaled or for a specified timeout to expire. It can be
4855 * interrupted by a kill signal. The timeout is in jiffies.
4858 wait_for_completion_killable_timeout(struct completion
*x
,
4859 unsigned long timeout
)
4861 return wait_for_common(x
, timeout
, TASK_KILLABLE
);
4863 EXPORT_SYMBOL(wait_for_completion_killable_timeout
);
4866 * try_wait_for_completion - try to decrement a completion without blocking
4867 * @x: completion structure
4869 * Returns: 0 if a decrement cannot be done without blocking
4870 * 1 if a decrement succeeded.
4872 * If a completion is being used as a counting completion,
4873 * attempt to decrement the counter without blocking. This
4874 * enables us to avoid waiting if the resource the completion
4875 * is protecting is not available.
4877 bool try_wait_for_completion(struct completion
*x
)
4879 unsigned long flags
;
4882 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4887 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4890 EXPORT_SYMBOL(try_wait_for_completion
);
4893 * completion_done - Test to see if a completion has any waiters
4894 * @x: completion structure
4896 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4897 * 1 if there are no waiters.
4900 bool completion_done(struct completion
*x
)
4902 unsigned long flags
;
4905 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4908 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4911 EXPORT_SYMBOL(completion_done
);
4914 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4916 unsigned long flags
;
4919 init_waitqueue_entry(&wait
, current
);
4921 __set_current_state(state
);
4923 spin_lock_irqsave(&q
->lock
, flags
);
4924 __add_wait_queue(q
, &wait
);
4925 spin_unlock(&q
->lock
);
4926 timeout
= schedule_timeout(timeout
);
4927 spin_lock_irq(&q
->lock
);
4928 __remove_wait_queue(q
, &wait
);
4929 spin_unlock_irqrestore(&q
->lock
, flags
);
4934 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4936 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4938 EXPORT_SYMBOL(interruptible_sleep_on
);
4941 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4943 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4945 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4947 void __sched
sleep_on(wait_queue_head_t
*q
)
4949 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4951 EXPORT_SYMBOL(sleep_on
);
4953 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4955 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4957 EXPORT_SYMBOL(sleep_on_timeout
);
4959 #ifdef CONFIG_RT_MUTEXES
4962 * rt_mutex_setprio - set the current priority of a task
4964 * @prio: prio value (kernel-internal form)
4966 * This function changes the 'effective' priority of a task. It does
4967 * not touch ->normal_prio like __setscheduler().
4969 * Used by the rt_mutex code to implement priority inheritance logic.
4971 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4973 int oldprio
, on_rq
, running
;
4975 const struct sched_class
*prev_class
;
4977 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4979 rq
= __task_rq_lock(p
);
4981 trace_sched_pi_setprio(p
, prio
);
4983 prev_class
= p
->sched_class
;
4985 running
= task_current(rq
, p
);
4987 dequeue_task(rq
, p
, 0);
4989 p
->sched_class
->put_prev_task(rq
, p
);
4992 p
->sched_class
= &rt_sched_class
;
4994 p
->sched_class
= &fair_sched_class
;
4999 p
->sched_class
->set_curr_task(rq
);
5001 enqueue_task(rq
, p
, oldprio
< prio
? ENQUEUE_HEAD
: 0);
5003 check_class_changed(rq
, p
, prev_class
, oldprio
);
5004 __task_rq_unlock(rq
);
5009 void set_user_nice(struct task_struct
*p
, long nice
)
5011 int old_prio
, delta
, on_rq
;
5012 unsigned long flags
;
5015 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
5018 * We have to be careful, if called from sys_setpriority(),
5019 * the task might be in the middle of scheduling on another CPU.
5021 rq
= task_rq_lock(p
, &flags
);
5023 * The RT priorities are set via sched_setscheduler(), but we still
5024 * allow the 'normal' nice value to be set - but as expected
5025 * it wont have any effect on scheduling until the task is
5026 * SCHED_FIFO/SCHED_RR:
5028 if (task_has_rt_policy(p
)) {
5029 p
->static_prio
= NICE_TO_PRIO(nice
);
5034 dequeue_task(rq
, p
, 0);
5036 p
->static_prio
= NICE_TO_PRIO(nice
);
5039 p
->prio
= effective_prio(p
);
5040 delta
= p
->prio
- old_prio
;
5043 enqueue_task(rq
, p
, 0);
5045 * If the task increased its priority or is running and
5046 * lowered its priority, then reschedule its CPU:
5048 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
5049 resched_task(rq
->curr
);
5052 task_rq_unlock(rq
, p
, &flags
);
5054 EXPORT_SYMBOL(set_user_nice
);
5057 * can_nice - check if a task can reduce its nice value
5061 int can_nice(const struct task_struct
*p
, const int nice
)
5063 /* convert nice value [19,-20] to rlimit style value [1,40] */
5064 int nice_rlim
= 20 - nice
;
5066 return (nice_rlim
<= task_rlimit(p
, RLIMIT_NICE
) ||
5067 capable(CAP_SYS_NICE
));
5070 #ifdef __ARCH_WANT_SYS_NICE
5073 * sys_nice - change the priority of the current process.
5074 * @increment: priority increment
5076 * sys_setpriority is a more generic, but much slower function that
5077 * does similar things.
5079 SYSCALL_DEFINE1(nice
, int, increment
)
5084 * Setpriority might change our priority at the same moment.
5085 * We don't have to worry. Conceptually one call occurs first
5086 * and we have a single winner.
5088 if (increment
< -40)
5093 nice
= TASK_NICE(current
) + increment
;
5099 if (increment
< 0 && !can_nice(current
, nice
))
5102 retval
= security_task_setnice(current
, nice
);
5106 set_user_nice(current
, nice
);
5113 * task_prio - return the priority value of a given task.
5114 * @p: the task in question.
5116 * This is the priority value as seen by users in /proc.
5117 * RT tasks are offset by -200. Normal tasks are centered
5118 * around 0, value goes from -16 to +15.
5120 int task_prio(const struct task_struct
*p
)
5122 return p
->prio
- MAX_RT_PRIO
;
5126 * task_nice - return the nice value of a given task.
5127 * @p: the task in question.
5129 int task_nice(const struct task_struct
*p
)
5131 return TASK_NICE(p
);
5133 EXPORT_SYMBOL(task_nice
);
5136 * idle_cpu - is a given cpu idle currently?
5137 * @cpu: the processor in question.
5139 int idle_cpu(int cpu
)
5141 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
5145 * idle_task - return the idle task for a given cpu.
5146 * @cpu: the processor in question.
5148 struct task_struct
*idle_task(int cpu
)
5150 return cpu_rq(cpu
)->idle
;
5154 * find_process_by_pid - find a process with a matching PID value.
5155 * @pid: the pid in question.
5157 static struct task_struct
*find_process_by_pid(pid_t pid
)
5159 return pid
? find_task_by_vpid(pid
) : current
;
5162 /* Actually do priority change: must hold rq lock. */
5164 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
5167 p
->rt_priority
= prio
;
5168 p
->normal_prio
= normal_prio(p
);
5169 /* we are holding p->pi_lock already */
5170 p
->prio
= rt_mutex_getprio(p
);
5171 if (rt_prio(p
->prio
))
5172 p
->sched_class
= &rt_sched_class
;
5174 p
->sched_class
= &fair_sched_class
;
5179 * check the target process has a UID that matches the current process's
5181 static bool check_same_owner(struct task_struct
*p
)
5183 const struct cred
*cred
= current_cred(), *pcred
;
5187 pcred
= __task_cred(p
);
5188 if (cred
->user
->user_ns
== pcred
->user
->user_ns
)
5189 match
= (cred
->euid
== pcred
->euid
||
5190 cred
->euid
== pcred
->uid
);
5197 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
5198 const struct sched_param
*param
, bool user
)
5200 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
5201 unsigned long flags
;
5202 const struct sched_class
*prev_class
;
5206 /* may grab non-irq protected spin_locks */
5207 BUG_ON(in_interrupt());
5209 /* double check policy once rq lock held */
5211 reset_on_fork
= p
->sched_reset_on_fork
;
5212 policy
= oldpolicy
= p
->policy
;
5214 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
5215 policy
&= ~SCHED_RESET_ON_FORK
;
5217 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
5218 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
5219 policy
!= SCHED_IDLE
)
5224 * Valid priorities for SCHED_FIFO and SCHED_RR are
5225 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5226 * SCHED_BATCH and SCHED_IDLE is 0.
5228 if (param
->sched_priority
< 0 ||
5229 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
5230 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
5232 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
5236 * Allow unprivileged RT tasks to decrease priority:
5238 if (user
&& !capable(CAP_SYS_NICE
)) {
5239 if (rt_policy(policy
)) {
5240 unsigned long rlim_rtprio
=
5241 task_rlimit(p
, RLIMIT_RTPRIO
);
5243 /* can't set/change the rt policy */
5244 if (policy
!= p
->policy
&& !rlim_rtprio
)
5247 /* can't increase priority */
5248 if (param
->sched_priority
> p
->rt_priority
&&
5249 param
->sched_priority
> rlim_rtprio
)
5254 * Treat SCHED_IDLE as nice 20. Only allow a switch to
5255 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
5257 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
) {
5258 if (!can_nice(p
, TASK_NICE(p
)))
5262 /* can't change other user's priorities */
5263 if (!check_same_owner(p
))
5266 /* Normal users shall not reset the sched_reset_on_fork flag */
5267 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
5272 retval
= security_task_setscheduler(p
);
5278 * make sure no PI-waiters arrive (or leave) while we are
5279 * changing the priority of the task:
5281 * To be able to change p->policy safely, the appropriate
5282 * runqueue lock must be held.
5284 rq
= task_rq_lock(p
, &flags
);
5287 * Changing the policy of the stop threads its a very bad idea
5289 if (p
== rq
->stop
) {
5290 task_rq_unlock(rq
, p
, &flags
);
5295 * If not changing anything there's no need to proceed further:
5297 if (unlikely(policy
== p
->policy
&& (!rt_policy(policy
) ||
5298 param
->sched_priority
== p
->rt_priority
))) {
5300 __task_rq_unlock(rq
);
5301 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5305 #ifdef CONFIG_RT_GROUP_SCHED
5308 * Do not allow realtime tasks into groups that have no runtime
5311 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
5312 task_group(p
)->rt_bandwidth
.rt_runtime
== 0 &&
5313 !task_group_is_autogroup(task_group(p
))) {
5314 task_rq_unlock(rq
, p
, &flags
);
5320 /* recheck policy now with rq lock held */
5321 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
5322 policy
= oldpolicy
= -1;
5323 task_rq_unlock(rq
, p
, &flags
);
5327 running
= task_current(rq
, p
);
5329 deactivate_task(rq
, p
, 0);
5331 p
->sched_class
->put_prev_task(rq
, p
);
5333 p
->sched_reset_on_fork
= reset_on_fork
;
5336 prev_class
= p
->sched_class
;
5337 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
5340 p
->sched_class
->set_curr_task(rq
);
5342 activate_task(rq
, p
, 0);
5344 check_class_changed(rq
, p
, prev_class
, oldprio
);
5345 task_rq_unlock(rq
, p
, &flags
);
5347 rt_mutex_adjust_pi(p
);
5353 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5354 * @p: the task in question.
5355 * @policy: new policy.
5356 * @param: structure containing the new RT priority.
5358 * NOTE that the task may be already dead.
5360 int sched_setscheduler(struct task_struct
*p
, int policy
,
5361 const struct sched_param
*param
)
5363 return __sched_setscheduler(p
, policy
, param
, true);
5365 EXPORT_SYMBOL_GPL(sched_setscheduler
);
5368 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5369 * @p: the task in question.
5370 * @policy: new policy.
5371 * @param: structure containing the new RT priority.
5373 * Just like sched_setscheduler, only don't bother checking if the
5374 * current context has permission. For example, this is needed in
5375 * stop_machine(): we create temporary high priority worker threads,
5376 * but our caller might not have that capability.
5378 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
5379 const struct sched_param
*param
)
5381 return __sched_setscheduler(p
, policy
, param
, false);
5385 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5387 struct sched_param lparam
;
5388 struct task_struct
*p
;
5391 if (!param
|| pid
< 0)
5393 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
5398 p
= find_process_by_pid(pid
);
5400 retval
= sched_setscheduler(p
, policy
, &lparam
);
5407 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5408 * @pid: the pid in question.
5409 * @policy: new policy.
5410 * @param: structure containing the new RT priority.
5412 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
5413 struct sched_param __user
*, param
)
5415 /* negative values for policy are not valid */
5419 return do_sched_setscheduler(pid
, policy
, param
);
5423 * sys_sched_setparam - set/change the RT priority of a thread
5424 * @pid: the pid in question.
5425 * @param: structure containing the new RT priority.
5427 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5429 return do_sched_setscheduler(pid
, -1, param
);
5433 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5434 * @pid: the pid in question.
5436 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
5438 struct task_struct
*p
;
5446 p
= find_process_by_pid(pid
);
5448 retval
= security_task_getscheduler(p
);
5451 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
5458 * sys_sched_getparam - get the RT priority of a thread
5459 * @pid: the pid in question.
5460 * @param: structure containing the RT priority.
5462 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5464 struct sched_param lp
;
5465 struct task_struct
*p
;
5468 if (!param
|| pid
< 0)
5472 p
= find_process_by_pid(pid
);
5477 retval
= security_task_getscheduler(p
);
5481 lp
.sched_priority
= p
->rt_priority
;
5485 * This one might sleep, we cannot do it with a spinlock held ...
5487 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
5496 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
5498 cpumask_var_t cpus_allowed
, new_mask
;
5499 struct task_struct
*p
;
5505 p
= find_process_by_pid(pid
);
5512 /* Prevent p going away */
5516 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
5520 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
5522 goto out_free_cpus_allowed
;
5525 if (!check_same_owner(p
) && !task_ns_capable(p
, CAP_SYS_NICE
))
5528 retval
= security_task_setscheduler(p
);
5532 cpuset_cpus_allowed(p
, cpus_allowed
);
5533 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
5535 retval
= set_cpus_allowed_ptr(p
, new_mask
);
5538 cpuset_cpus_allowed(p
, cpus_allowed
);
5539 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
5541 * We must have raced with a concurrent cpuset
5542 * update. Just reset the cpus_allowed to the
5543 * cpuset's cpus_allowed
5545 cpumask_copy(new_mask
, cpus_allowed
);
5550 free_cpumask_var(new_mask
);
5551 out_free_cpus_allowed
:
5552 free_cpumask_var(cpus_allowed
);
5559 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5560 struct cpumask
*new_mask
)
5562 if (len
< cpumask_size())
5563 cpumask_clear(new_mask
);
5564 else if (len
> cpumask_size())
5565 len
= cpumask_size();
5567 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5571 * sys_sched_setaffinity - set the cpu affinity of a process
5572 * @pid: pid of the process
5573 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5574 * @user_mask_ptr: user-space pointer to the new cpu mask
5576 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
5577 unsigned long __user
*, user_mask_ptr
)
5579 cpumask_var_t new_mask
;
5582 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
5585 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
5587 retval
= sched_setaffinity(pid
, new_mask
);
5588 free_cpumask_var(new_mask
);
5592 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
5594 struct task_struct
*p
;
5595 unsigned long flags
;
5602 p
= find_process_by_pid(pid
);
5606 retval
= security_task_getscheduler(p
);
5610 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
5611 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
5612 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5622 * sys_sched_getaffinity - get the cpu affinity of a process
5623 * @pid: pid of the process
5624 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5625 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5627 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
5628 unsigned long __user
*, user_mask_ptr
)
5633 if ((len
* BITS_PER_BYTE
) < nr_cpu_ids
)
5635 if (len
& (sizeof(unsigned long)-1))
5638 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
5641 ret
= sched_getaffinity(pid
, mask
);
5643 size_t retlen
= min_t(size_t, len
, cpumask_size());
5645 if (copy_to_user(user_mask_ptr
, mask
, retlen
))
5650 free_cpumask_var(mask
);
5656 * sys_sched_yield - yield the current processor to other threads.
5658 * This function yields the current CPU to other tasks. If there are no
5659 * other threads running on this CPU then this function will return.
5661 SYSCALL_DEFINE0(sched_yield
)
5663 struct rq
*rq
= this_rq_lock();
5665 schedstat_inc(rq
, yld_count
);
5666 current
->sched_class
->yield_task(rq
);
5669 * Since we are going to call schedule() anyway, there's
5670 * no need to preempt or enable interrupts:
5672 __release(rq
->lock
);
5673 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5674 do_raw_spin_unlock(&rq
->lock
);
5675 preempt_enable_no_resched();
5682 static inline int should_resched(void)
5684 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
5687 static void __cond_resched(void)
5689 add_preempt_count(PREEMPT_ACTIVE
);
5691 sub_preempt_count(PREEMPT_ACTIVE
);
5694 int __sched
_cond_resched(void)
5696 if (should_resched()) {
5702 EXPORT_SYMBOL(_cond_resched
);
5705 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
5706 * call schedule, and on return reacquire the lock.
5708 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5709 * operations here to prevent schedule() from being called twice (once via
5710 * spin_unlock(), once by hand).
5712 int __cond_resched_lock(spinlock_t
*lock
)
5714 int resched
= should_resched();
5717 lockdep_assert_held(lock
);
5719 if (spin_needbreak(lock
) || resched
) {
5730 EXPORT_SYMBOL(__cond_resched_lock
);
5732 int __sched
__cond_resched_softirq(void)
5734 BUG_ON(!in_softirq());
5736 if (should_resched()) {
5744 EXPORT_SYMBOL(__cond_resched_softirq
);
5747 * yield - yield the current processor to other threads.
5749 * This is a shortcut for kernel-space yielding - it marks the
5750 * thread runnable and calls sys_sched_yield().
5752 void __sched
yield(void)
5754 set_current_state(TASK_RUNNING
);
5757 EXPORT_SYMBOL(yield
);
5760 * yield_to - yield the current processor to another thread in
5761 * your thread group, or accelerate that thread toward the
5762 * processor it's on.
5764 * @preempt: whether task preemption is allowed or not
5766 * It's the caller's job to ensure that the target task struct
5767 * can't go away on us before we can do any checks.
5769 * Returns true if we indeed boosted the target task.
5771 bool __sched
yield_to(struct task_struct
*p
, bool preempt
)
5773 struct task_struct
*curr
= current
;
5774 struct rq
*rq
, *p_rq
;
5775 unsigned long flags
;
5778 local_irq_save(flags
);
5783 double_rq_lock(rq
, p_rq
);
5784 while (task_rq(p
) != p_rq
) {
5785 double_rq_unlock(rq
, p_rq
);
5789 if (!curr
->sched_class
->yield_to_task
)
5792 if (curr
->sched_class
!= p
->sched_class
)
5795 if (task_running(p_rq
, p
) || p
->state
)
5798 yielded
= curr
->sched_class
->yield_to_task(rq
, p
, preempt
);
5800 schedstat_inc(rq
, yld_count
);
5802 * Make p's CPU reschedule; pick_next_entity takes care of
5805 if (preempt
&& rq
!= p_rq
)
5806 resched_task(p_rq
->curr
);
5810 double_rq_unlock(rq
, p_rq
);
5811 local_irq_restore(flags
);
5818 EXPORT_SYMBOL_GPL(yield_to
);
5821 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5822 * that process accounting knows that this is a task in IO wait state.
5824 void __sched
io_schedule(void)
5826 struct rq
*rq
= raw_rq();
5828 delayacct_blkio_start();
5829 atomic_inc(&rq
->nr_iowait
);
5830 blk_flush_plug(current
);
5831 current
->in_iowait
= 1;
5833 current
->in_iowait
= 0;
5834 atomic_dec(&rq
->nr_iowait
);
5835 delayacct_blkio_end();
5837 EXPORT_SYMBOL(io_schedule
);
5839 long __sched
io_schedule_timeout(long timeout
)
5841 struct rq
*rq
= raw_rq();
5844 delayacct_blkio_start();
5845 atomic_inc(&rq
->nr_iowait
);
5846 blk_flush_plug(current
);
5847 current
->in_iowait
= 1;
5848 ret
= schedule_timeout(timeout
);
5849 current
->in_iowait
= 0;
5850 atomic_dec(&rq
->nr_iowait
);
5851 delayacct_blkio_end();
5856 * sys_sched_get_priority_max - return maximum RT priority.
5857 * @policy: scheduling class.
5859 * this syscall returns the maximum rt_priority that can be used
5860 * by a given scheduling class.
5862 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
5869 ret
= MAX_USER_RT_PRIO
-1;
5881 * sys_sched_get_priority_min - return minimum RT priority.
5882 * @policy: scheduling class.
5884 * this syscall returns the minimum rt_priority that can be used
5885 * by a given scheduling class.
5887 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
5905 * sys_sched_rr_get_interval - return the default timeslice of a process.
5906 * @pid: pid of the process.
5907 * @interval: userspace pointer to the timeslice value.
5909 * this syscall writes the default timeslice value of a given process
5910 * into the user-space timespec buffer. A value of '0' means infinity.
5912 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
5913 struct timespec __user
*, interval
)
5915 struct task_struct
*p
;
5916 unsigned int time_slice
;
5917 unsigned long flags
;
5927 p
= find_process_by_pid(pid
);
5931 retval
= security_task_getscheduler(p
);
5935 rq
= task_rq_lock(p
, &flags
);
5936 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
5937 task_rq_unlock(rq
, p
, &flags
);
5940 jiffies_to_timespec(time_slice
, &t
);
5941 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5949 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5951 void sched_show_task(struct task_struct
*p
)
5953 unsigned long free
= 0;
5956 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5957 printk(KERN_INFO
"%-15.15s %c", p
->comm
,
5958 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5959 #if BITS_PER_LONG == 32
5960 if (state
== TASK_RUNNING
)
5961 printk(KERN_CONT
" running ");
5963 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5965 if (state
== TASK_RUNNING
)
5966 printk(KERN_CONT
" running task ");
5968 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5970 #ifdef CONFIG_DEBUG_STACK_USAGE
5971 free
= stack_not_used(p
);
5973 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
5974 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
5975 (unsigned long)task_thread_info(p
)->flags
);
5977 show_stack(p
, NULL
);
5980 void show_state_filter(unsigned long state_filter
)
5982 struct task_struct
*g
, *p
;
5984 #if BITS_PER_LONG == 32
5986 " task PC stack pid father\n");
5989 " task PC stack pid father\n");
5991 read_lock(&tasklist_lock
);
5992 do_each_thread(g
, p
) {
5994 * reset the NMI-timeout, listing all files on a slow
5995 * console might take a lot of time:
5997 touch_nmi_watchdog();
5998 if (!state_filter
|| (p
->state
& state_filter
))
6000 } while_each_thread(g
, p
);
6002 touch_all_softlockup_watchdogs();
6004 #ifdef CONFIG_SCHED_DEBUG
6005 sysrq_sched_debug_show();
6007 read_unlock(&tasklist_lock
);
6009 * Only show locks if all tasks are dumped:
6012 debug_show_all_locks();
6015 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6017 idle
->sched_class
= &idle_sched_class
;
6021 * init_idle - set up an idle thread for a given CPU
6022 * @idle: task in question
6023 * @cpu: cpu the idle task belongs to
6025 * NOTE: this function does not set the idle thread's NEED_RESCHED
6026 * flag, to make booting more robust.
6028 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6030 struct rq
*rq
= cpu_rq(cpu
);
6031 unsigned long flags
;
6033 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6036 idle
->state
= TASK_RUNNING
;
6037 idle
->se
.exec_start
= sched_clock();
6039 do_set_cpus_allowed(idle
, cpumask_of(cpu
));
6041 * We're having a chicken and egg problem, even though we are
6042 * holding rq->lock, the cpu isn't yet set to this cpu so the
6043 * lockdep check in task_group() will fail.
6045 * Similar case to sched_fork(). / Alternatively we could
6046 * use task_rq_lock() here and obtain the other rq->lock.
6051 __set_task_cpu(idle
, cpu
);
6054 rq
->curr
= rq
->idle
= idle
;
6055 #if defined(CONFIG_SMP)
6058 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6060 /* Set the preempt count _outside_ the spinlocks! */
6061 task_thread_info(idle
)->preempt_count
= 0;
6064 * The idle tasks have their own, simple scheduling class:
6066 idle
->sched_class
= &idle_sched_class
;
6067 ftrace_graph_init_idle_task(idle
, cpu
);
6071 * In a system that switches off the HZ timer nohz_cpu_mask
6072 * indicates which cpus entered this state. This is used
6073 * in the rcu update to wait only for active cpus. For system
6074 * which do not switch off the HZ timer nohz_cpu_mask should
6075 * always be CPU_BITS_NONE.
6077 cpumask_var_t nohz_cpu_mask
;
6080 * Increase the granularity value when there are more CPUs,
6081 * because with more CPUs the 'effective latency' as visible
6082 * to users decreases. But the relationship is not linear,
6083 * so pick a second-best guess by going with the log2 of the
6086 * This idea comes from the SD scheduler of Con Kolivas:
6088 static int get_update_sysctl_factor(void)
6090 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
6091 unsigned int factor
;
6093 switch (sysctl_sched_tunable_scaling
) {
6094 case SCHED_TUNABLESCALING_NONE
:
6097 case SCHED_TUNABLESCALING_LINEAR
:
6100 case SCHED_TUNABLESCALING_LOG
:
6102 factor
= 1 + ilog2(cpus
);
6109 static void update_sysctl(void)
6111 unsigned int factor
= get_update_sysctl_factor();
6113 #define SET_SYSCTL(name) \
6114 (sysctl_##name = (factor) * normalized_sysctl_##name)
6115 SET_SYSCTL(sched_min_granularity
);
6116 SET_SYSCTL(sched_latency
);
6117 SET_SYSCTL(sched_wakeup_granularity
);
6121 static inline void sched_init_granularity(void)
6127 void do_set_cpus_allowed(struct task_struct
*p
, const struct cpumask
*new_mask
)
6129 if (p
->sched_class
&& p
->sched_class
->set_cpus_allowed
)
6130 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
6132 cpumask_copy(&p
->cpus_allowed
, new_mask
);
6133 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
6138 * This is how migration works:
6140 * 1) we invoke migration_cpu_stop() on the target CPU using
6142 * 2) stopper starts to run (implicitly forcing the migrated thread
6144 * 3) it checks whether the migrated task is still in the wrong runqueue.
6145 * 4) if it's in the wrong runqueue then the migration thread removes
6146 * it and puts it into the right queue.
6147 * 5) stopper completes and stop_one_cpu() returns and the migration
6152 * Change a given task's CPU affinity. Migrate the thread to a
6153 * proper CPU and schedule it away if the CPU it's executing on
6154 * is removed from the allowed bitmask.
6156 * NOTE: the caller must have a valid reference to the task, the
6157 * task must not exit() & deallocate itself prematurely. The
6158 * call is not atomic; no spinlocks may be held.
6160 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
6162 unsigned long flags
;
6164 unsigned int dest_cpu
;
6167 rq
= task_rq_lock(p
, &flags
);
6169 if (cpumask_equal(&p
->cpus_allowed
, new_mask
))
6172 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
6177 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
)) {
6182 do_set_cpus_allowed(p
, new_mask
);
6184 /* Can the task run on the task's current CPU? If so, we're done */
6185 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
6188 dest_cpu
= cpumask_any_and(cpu_active_mask
, new_mask
);
6190 struct migration_arg arg
= { p
, dest_cpu
};
6191 /* Need help from migration thread: drop lock and wait. */
6192 task_rq_unlock(rq
, p
, &flags
);
6193 stop_one_cpu(cpu_of(rq
), migration_cpu_stop
, &arg
);
6194 tlb_migrate_finish(p
->mm
);
6198 task_rq_unlock(rq
, p
, &flags
);
6202 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
6205 * Move (not current) task off this cpu, onto dest cpu. We're doing
6206 * this because either it can't run here any more (set_cpus_allowed()
6207 * away from this CPU, or CPU going down), or because we're
6208 * attempting to rebalance this task on exec (sched_exec).
6210 * So we race with normal scheduler movements, but that's OK, as long
6211 * as the task is no longer on this CPU.
6213 * Returns non-zero if task was successfully migrated.
6215 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6217 struct rq
*rq_dest
, *rq_src
;
6220 if (unlikely(!cpu_active(dest_cpu
)))
6223 rq_src
= cpu_rq(src_cpu
);
6224 rq_dest
= cpu_rq(dest_cpu
);
6226 raw_spin_lock(&p
->pi_lock
);
6227 double_rq_lock(rq_src
, rq_dest
);
6228 /* Already moved. */
6229 if (task_cpu(p
) != src_cpu
)
6231 /* Affinity changed (again). */
6232 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6236 * If we're not on a rq, the next wake-up will ensure we're
6240 deactivate_task(rq_src
, p
, 0);
6241 set_task_cpu(p
, dest_cpu
);
6242 activate_task(rq_dest
, p
, 0);
6243 check_preempt_curr(rq_dest
, p
, 0);
6248 double_rq_unlock(rq_src
, rq_dest
);
6249 raw_spin_unlock(&p
->pi_lock
);
6254 * migration_cpu_stop - this will be executed by a highprio stopper thread
6255 * and performs thread migration by bumping thread off CPU then
6256 * 'pushing' onto another runqueue.
6258 static int migration_cpu_stop(void *data
)
6260 struct migration_arg
*arg
= data
;
6263 * The original target cpu might have gone down and we might
6264 * be on another cpu but it doesn't matter.
6266 local_irq_disable();
6267 __migrate_task(arg
->task
, raw_smp_processor_id(), arg
->dest_cpu
);
6272 #ifdef CONFIG_HOTPLUG_CPU
6275 * Ensures that the idle task is using init_mm right before its cpu goes
6278 void idle_task_exit(void)
6280 struct mm_struct
*mm
= current
->active_mm
;
6282 BUG_ON(cpu_online(smp_processor_id()));
6285 switch_mm(mm
, &init_mm
, current
);
6290 * While a dead CPU has no uninterruptible tasks queued at this point,
6291 * it might still have a nonzero ->nr_uninterruptible counter, because
6292 * for performance reasons the counter is not stricly tracking tasks to
6293 * their home CPUs. So we just add the counter to another CPU's counter,
6294 * to keep the global sum constant after CPU-down:
6296 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6298 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
6300 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6301 rq_src
->nr_uninterruptible
= 0;
6305 * remove the tasks which were accounted by rq from calc_load_tasks.
6307 static void calc_global_load_remove(struct rq
*rq
)
6309 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
6310 rq
->calc_load_active
= 0;
6313 #ifdef CONFIG_CFS_BANDWIDTH
6314 static void unthrottle_offline_cfs_rqs(struct rq
*rq
)
6316 struct cfs_rq
*cfs_rq
;
6318 for_each_leaf_cfs_rq(rq
, cfs_rq
) {
6319 struct cfs_bandwidth
*cfs_b
= tg_cfs_bandwidth(cfs_rq
->tg
);
6321 if (!cfs_rq
->runtime_enabled
)
6325 * clock_task is not advancing so we just need to make sure
6326 * there's some valid quota amount
6328 cfs_rq
->runtime_remaining
= cfs_b
->quota
;
6329 if (cfs_rq_throttled(cfs_rq
))
6330 unthrottle_cfs_rq(cfs_rq
);
6334 static void unthrottle_offline_cfs_rqs(struct rq
*rq
) {}
6338 * Migrate all tasks from the rq, sleeping tasks will be migrated by
6339 * try_to_wake_up()->select_task_rq().
6341 * Called with rq->lock held even though we'er in stop_machine() and
6342 * there's no concurrency possible, we hold the required locks anyway
6343 * because of lock validation efforts.
6345 static void migrate_tasks(unsigned int dead_cpu
)
6347 struct rq
*rq
= cpu_rq(dead_cpu
);
6348 struct task_struct
*next
, *stop
= rq
->stop
;
6352 * Fudge the rq selection such that the below task selection loop
6353 * doesn't get stuck on the currently eligible stop task.
6355 * We're currently inside stop_machine() and the rq is either stuck
6356 * in the stop_machine_cpu_stop() loop, or we're executing this code,
6357 * either way we should never end up calling schedule() until we're
6362 /* Ensure any throttled groups are reachable by pick_next_task */
6363 unthrottle_offline_cfs_rqs(rq
);
6367 * There's this thread running, bail when that's the only
6370 if (rq
->nr_running
== 1)
6373 next
= pick_next_task(rq
);
6375 next
->sched_class
->put_prev_task(rq
, next
);
6377 /* Find suitable destination for @next, with force if needed. */
6378 dest_cpu
= select_fallback_rq(dead_cpu
, next
);
6379 raw_spin_unlock(&rq
->lock
);
6381 __migrate_task(next
, dead_cpu
, dest_cpu
);
6383 raw_spin_lock(&rq
->lock
);
6389 #endif /* CONFIG_HOTPLUG_CPU */
6391 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6393 static struct ctl_table sd_ctl_dir
[] = {
6395 .procname
= "sched_domain",
6401 static struct ctl_table sd_ctl_root
[] = {
6403 .procname
= "kernel",
6405 .child
= sd_ctl_dir
,
6410 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
6412 struct ctl_table
*entry
=
6413 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
6418 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
6420 struct ctl_table
*entry
;
6423 * In the intermediate directories, both the child directory and
6424 * procname are dynamically allocated and could fail but the mode
6425 * will always be set. In the lowest directory the names are
6426 * static strings and all have proc handlers.
6428 for (entry
= *tablep
; entry
->mode
; entry
++) {
6430 sd_free_ctl_entry(&entry
->child
);
6431 if (entry
->proc_handler
== NULL
)
6432 kfree(entry
->procname
);
6440 set_table_entry(struct ctl_table
*entry
,
6441 const char *procname
, void *data
, int maxlen
,
6442 mode_t mode
, proc_handler
*proc_handler
)
6444 entry
->procname
= procname
;
6446 entry
->maxlen
= maxlen
;
6448 entry
->proc_handler
= proc_handler
;
6451 static struct ctl_table
*
6452 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
6454 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
6459 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
6460 sizeof(long), 0644, proc_doulongvec_minmax
);
6461 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
6462 sizeof(long), 0644, proc_doulongvec_minmax
);
6463 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
6464 sizeof(int), 0644, proc_dointvec_minmax
);
6465 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
6466 sizeof(int), 0644, proc_dointvec_minmax
);
6467 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
6468 sizeof(int), 0644, proc_dointvec_minmax
);
6469 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
6470 sizeof(int), 0644, proc_dointvec_minmax
);
6471 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
6472 sizeof(int), 0644, proc_dointvec_minmax
);
6473 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
6474 sizeof(int), 0644, proc_dointvec_minmax
);
6475 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
6476 sizeof(int), 0644, proc_dointvec_minmax
);
6477 set_table_entry(&table
[9], "cache_nice_tries",
6478 &sd
->cache_nice_tries
,
6479 sizeof(int), 0644, proc_dointvec_minmax
);
6480 set_table_entry(&table
[10], "flags", &sd
->flags
,
6481 sizeof(int), 0644, proc_dointvec_minmax
);
6482 set_table_entry(&table
[11], "name", sd
->name
,
6483 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
6484 /* &table[12] is terminator */
6489 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
6491 struct ctl_table
*entry
, *table
;
6492 struct sched_domain
*sd
;
6493 int domain_num
= 0, i
;
6496 for_each_domain(cpu
, sd
)
6498 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6503 for_each_domain(cpu
, sd
) {
6504 snprintf(buf
, 32, "domain%d", i
);
6505 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6507 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6514 static struct ctl_table_header
*sd_sysctl_header
;
6515 static void register_sched_domain_sysctl(void)
6517 int i
, cpu_num
= num_possible_cpus();
6518 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6521 WARN_ON(sd_ctl_dir
[0].child
);
6522 sd_ctl_dir
[0].child
= entry
;
6527 for_each_possible_cpu(i
) {
6528 snprintf(buf
, 32, "cpu%d", i
);
6529 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6531 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6535 WARN_ON(sd_sysctl_header
);
6536 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6539 /* may be called multiple times per register */
6540 static void unregister_sched_domain_sysctl(void)
6542 if (sd_sysctl_header
)
6543 unregister_sysctl_table(sd_sysctl_header
);
6544 sd_sysctl_header
= NULL
;
6545 if (sd_ctl_dir
[0].child
)
6546 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6549 static void register_sched_domain_sysctl(void)
6552 static void unregister_sched_domain_sysctl(void)
6557 static void set_rq_online(struct rq
*rq
)
6560 const struct sched_class
*class;
6562 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
6565 for_each_class(class) {
6566 if (class->rq_online
)
6567 class->rq_online(rq
);
6572 static void set_rq_offline(struct rq
*rq
)
6575 const struct sched_class
*class;
6577 for_each_class(class) {
6578 if (class->rq_offline
)
6579 class->rq_offline(rq
);
6582 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
6588 * migration_call - callback that gets triggered when a CPU is added.
6589 * Here we can start up the necessary migration thread for the new CPU.
6591 static int __cpuinit
6592 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6594 int cpu
= (long)hcpu
;
6595 unsigned long flags
;
6596 struct rq
*rq
= cpu_rq(cpu
);
6598 switch (action
& ~CPU_TASKS_FROZEN
) {
6600 case CPU_UP_PREPARE
:
6601 rq
->calc_load_update
= calc_load_update
;
6605 /* Update our root-domain */
6606 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6608 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6612 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6615 #ifdef CONFIG_HOTPLUG_CPU
6617 sched_ttwu_pending();
6618 /* Update our root-domain */
6619 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6621 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6625 BUG_ON(rq
->nr_running
!= 1); /* the migration thread */
6626 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6628 migrate_nr_uninterruptible(rq
);
6629 calc_global_load_remove(rq
);
6634 update_max_interval();
6640 * Register at high priority so that task migration (migrate_all_tasks)
6641 * happens before everything else. This has to be lower priority than
6642 * the notifier in the perf_event subsystem, though.
6644 static struct notifier_block __cpuinitdata migration_notifier
= {
6645 .notifier_call
= migration_call
,
6646 .priority
= CPU_PRI_MIGRATION
,
6649 static int __cpuinit
sched_cpu_active(struct notifier_block
*nfb
,
6650 unsigned long action
, void *hcpu
)
6652 switch (action
& ~CPU_TASKS_FROZEN
) {
6654 case CPU_DOWN_FAILED
:
6655 set_cpu_active((long)hcpu
, true);
6662 static int __cpuinit
sched_cpu_inactive(struct notifier_block
*nfb
,
6663 unsigned long action
, void *hcpu
)
6665 switch (action
& ~CPU_TASKS_FROZEN
) {
6666 case CPU_DOWN_PREPARE
:
6667 set_cpu_active((long)hcpu
, false);
6674 static int __init
migration_init(void)
6676 void *cpu
= (void *)(long)smp_processor_id();
6679 /* Initialize migration for the boot CPU */
6680 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6681 BUG_ON(err
== NOTIFY_BAD
);
6682 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6683 register_cpu_notifier(&migration_notifier
);
6685 /* Register cpu active notifiers */
6686 cpu_notifier(sched_cpu_active
, CPU_PRI_SCHED_ACTIVE
);
6687 cpu_notifier(sched_cpu_inactive
, CPU_PRI_SCHED_INACTIVE
);
6691 early_initcall(migration_init
);
6696 static cpumask_var_t sched_domains_tmpmask
; /* sched_domains_mutex */
6698 #ifdef CONFIG_SCHED_DEBUG
6700 static __read_mostly
int sched_domain_debug_enabled
;
6702 static int __init
sched_domain_debug_setup(char *str
)
6704 sched_domain_debug_enabled
= 1;
6708 early_param("sched_debug", sched_domain_debug_setup
);
6710 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6711 struct cpumask
*groupmask
)
6713 struct sched_group
*group
= sd
->groups
;
6716 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
6717 cpumask_clear(groupmask
);
6719 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6721 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6722 printk("does not load-balance\n");
6724 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6729 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
6731 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
6732 printk(KERN_ERR
"ERROR: domain->span does not contain "
6735 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6736 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6740 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6744 printk(KERN_ERR
"ERROR: group is NULL\n");
6748 if (!group
->sgp
->power
) {
6749 printk(KERN_CONT
"\n");
6750 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6755 if (!cpumask_weight(sched_group_cpus(group
))) {
6756 printk(KERN_CONT
"\n");
6757 printk(KERN_ERR
"ERROR: empty group\n");
6761 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6762 printk(KERN_CONT
"\n");
6763 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6767 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6769 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6771 printk(KERN_CONT
" %s", str
);
6772 if (group
->sgp
->power
!= SCHED_POWER_SCALE
) {
6773 printk(KERN_CONT
" (cpu_power = %d)",
6777 group
= group
->next
;
6778 } while (group
!= sd
->groups
);
6779 printk(KERN_CONT
"\n");
6781 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6782 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6785 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6786 printk(KERN_ERR
"ERROR: parent span is not a superset "
6787 "of domain->span\n");
6791 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6795 if (!sched_domain_debug_enabled
)
6799 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6803 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6806 if (sched_domain_debug_one(sd
, cpu
, level
, sched_domains_tmpmask
))
6814 #else /* !CONFIG_SCHED_DEBUG */
6815 # define sched_domain_debug(sd, cpu) do { } while (0)
6816 #endif /* CONFIG_SCHED_DEBUG */
6818 static int sd_degenerate(struct sched_domain
*sd
)
6820 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6823 /* Following flags need at least 2 groups */
6824 if (sd
->flags
& (SD_LOAD_BALANCE
|
6825 SD_BALANCE_NEWIDLE
|
6829 SD_SHARE_PKG_RESOURCES
)) {
6830 if (sd
->groups
!= sd
->groups
->next
)
6834 /* Following flags don't use groups */
6835 if (sd
->flags
& (SD_WAKE_AFFINE
))
6842 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6844 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6846 if (sd_degenerate(parent
))
6849 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
6852 /* Flags needing groups don't count if only 1 group in parent */
6853 if (parent
->groups
== parent
->groups
->next
) {
6854 pflags
&= ~(SD_LOAD_BALANCE
|
6855 SD_BALANCE_NEWIDLE
|
6859 SD_SHARE_PKG_RESOURCES
);
6860 if (nr_node_ids
== 1)
6861 pflags
&= ~SD_SERIALIZE
;
6863 if (~cflags
& pflags
)
6869 static void free_rootdomain(struct rcu_head
*rcu
)
6871 struct root_domain
*rd
= container_of(rcu
, struct root_domain
, rcu
);
6873 cpupri_cleanup(&rd
->cpupri
);
6874 free_cpumask_var(rd
->rto_mask
);
6875 free_cpumask_var(rd
->online
);
6876 free_cpumask_var(rd
->span
);
6880 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6882 struct root_domain
*old_rd
= NULL
;
6883 unsigned long flags
;
6885 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6890 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
6893 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
6896 * If we dont want to free the old_rt yet then
6897 * set old_rd to NULL to skip the freeing later
6900 if (!atomic_dec_and_test(&old_rd
->refcount
))
6904 atomic_inc(&rd
->refcount
);
6907 cpumask_set_cpu(rq
->cpu
, rd
->span
);
6908 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
6911 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6914 call_rcu_sched(&old_rd
->rcu
, free_rootdomain
);
6917 static int init_rootdomain(struct root_domain
*rd
)
6919 memset(rd
, 0, sizeof(*rd
));
6921 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
6923 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
6925 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
6928 if (cpupri_init(&rd
->cpupri
) != 0)
6933 free_cpumask_var(rd
->rto_mask
);
6935 free_cpumask_var(rd
->online
);
6937 free_cpumask_var(rd
->span
);
6942 static void init_defrootdomain(void)
6944 init_rootdomain(&def_root_domain
);
6946 atomic_set(&def_root_domain
.refcount
, 1);
6949 static struct root_domain
*alloc_rootdomain(void)
6951 struct root_domain
*rd
;
6953 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6957 if (init_rootdomain(rd
) != 0) {
6965 static void free_sched_groups(struct sched_group
*sg
, int free_sgp
)
6967 struct sched_group
*tmp
, *first
;
6976 if (free_sgp
&& atomic_dec_and_test(&sg
->sgp
->ref
))
6981 } while (sg
!= first
);
6984 static void free_sched_domain(struct rcu_head
*rcu
)
6986 struct sched_domain
*sd
= container_of(rcu
, struct sched_domain
, rcu
);
6989 * If its an overlapping domain it has private groups, iterate and
6992 if (sd
->flags
& SD_OVERLAP
) {
6993 free_sched_groups(sd
->groups
, 1);
6994 } else if (atomic_dec_and_test(&sd
->groups
->ref
)) {
6995 kfree(sd
->groups
->sgp
);
7001 static void destroy_sched_domain(struct sched_domain
*sd
, int cpu
)
7003 call_rcu(&sd
->rcu
, free_sched_domain
);
7006 static void destroy_sched_domains(struct sched_domain
*sd
, int cpu
)
7008 for (; sd
; sd
= sd
->parent
)
7009 destroy_sched_domain(sd
, cpu
);
7013 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7014 * hold the hotplug lock.
7017 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
7019 struct rq
*rq
= cpu_rq(cpu
);
7020 struct sched_domain
*tmp
;
7022 /* Remove the sched domains which do not contribute to scheduling. */
7023 for (tmp
= sd
; tmp
; ) {
7024 struct sched_domain
*parent
= tmp
->parent
;
7028 if (sd_parent_degenerate(tmp
, parent
)) {
7029 tmp
->parent
= parent
->parent
;
7031 parent
->parent
->child
= tmp
;
7032 destroy_sched_domain(parent
, cpu
);
7037 if (sd
&& sd_degenerate(sd
)) {
7040 destroy_sched_domain(tmp
, cpu
);
7045 sched_domain_debug(sd
, cpu
);
7047 rq_attach_root(rq
, rd
);
7049 rcu_assign_pointer(rq
->sd
, sd
);
7050 destroy_sched_domains(tmp
, cpu
);
7053 /* cpus with isolated domains */
7054 static cpumask_var_t cpu_isolated_map
;
7056 /* Setup the mask of cpus configured for isolated domains */
7057 static int __init
isolated_cpu_setup(char *str
)
7059 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
7060 cpulist_parse(str
, cpu_isolated_map
);
7064 __setup("isolcpus=", isolated_cpu_setup
);
7066 #define SD_NODES_PER_DOMAIN 16
7071 * find_next_best_node - find the next node to include in a sched_domain
7072 * @node: node whose sched_domain we're building
7073 * @used_nodes: nodes already in the sched_domain
7075 * Find the next node to include in a given scheduling domain. Simply
7076 * finds the closest node not already in the @used_nodes map.
7078 * Should use nodemask_t.
7080 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
7082 int i
, n
, val
, min_val
, best_node
= -1;
7086 for (i
= 0; i
< nr_node_ids
; i
++) {
7087 /* Start at @node */
7088 n
= (node
+ i
) % nr_node_ids
;
7090 if (!nr_cpus_node(n
))
7093 /* Skip already used nodes */
7094 if (node_isset(n
, *used_nodes
))
7097 /* Simple min distance search */
7098 val
= node_distance(node
, n
);
7100 if (val
< min_val
) {
7106 if (best_node
!= -1)
7107 node_set(best_node
, *used_nodes
);
7112 * sched_domain_node_span - get a cpumask for a node's sched_domain
7113 * @node: node whose cpumask we're constructing
7114 * @span: resulting cpumask
7116 * Given a node, construct a good cpumask for its sched_domain to span. It
7117 * should be one that prevents unnecessary balancing, but also spreads tasks
7120 static void sched_domain_node_span(int node
, struct cpumask
*span
)
7122 nodemask_t used_nodes
;
7125 cpumask_clear(span
);
7126 nodes_clear(used_nodes
);
7128 cpumask_or(span
, span
, cpumask_of_node(node
));
7129 node_set(node
, used_nodes
);
7131 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
7132 int next_node
= find_next_best_node(node
, &used_nodes
);
7135 cpumask_or(span
, span
, cpumask_of_node(next_node
));
7139 static const struct cpumask
*cpu_node_mask(int cpu
)
7141 lockdep_assert_held(&sched_domains_mutex
);
7143 sched_domain_node_span(cpu_to_node(cpu
), sched_domains_tmpmask
);
7145 return sched_domains_tmpmask
;
7148 static const struct cpumask
*cpu_allnodes_mask(int cpu
)
7150 return cpu_possible_mask
;
7152 #endif /* CONFIG_NUMA */
7154 static const struct cpumask
*cpu_cpu_mask(int cpu
)
7156 return cpumask_of_node(cpu_to_node(cpu
));
7159 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
7162 struct sched_domain
**__percpu sd
;
7163 struct sched_group
**__percpu sg
;
7164 struct sched_group_power
**__percpu sgp
;
7168 struct sched_domain
** __percpu sd
;
7169 struct root_domain
*rd
;
7179 struct sched_domain_topology_level
;
7181 typedef struct sched_domain
*(*sched_domain_init_f
)(struct sched_domain_topology_level
*tl
, int cpu
);
7182 typedef const struct cpumask
*(*sched_domain_mask_f
)(int cpu
);
7184 #define SDTL_OVERLAP 0x01
7186 struct sched_domain_topology_level
{
7187 sched_domain_init_f init
;
7188 sched_domain_mask_f mask
;
7190 struct sd_data data
;
7194 build_overlap_sched_groups(struct sched_domain
*sd
, int cpu
)
7196 struct sched_group
*first
= NULL
, *last
= NULL
, *groups
= NULL
, *sg
;
7197 const struct cpumask
*span
= sched_domain_span(sd
);
7198 struct cpumask
*covered
= sched_domains_tmpmask
;
7199 struct sd_data
*sdd
= sd
->private;
7200 struct sched_domain
*child
;
7203 cpumask_clear(covered
);
7205 for_each_cpu(i
, span
) {
7206 struct cpumask
*sg_span
;
7208 if (cpumask_test_cpu(i
, covered
))
7211 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7212 GFP_KERNEL
, cpu_to_node(i
));
7217 sg_span
= sched_group_cpus(sg
);
7219 child
= *per_cpu_ptr(sdd
->sd
, i
);
7221 child
= child
->child
;
7222 cpumask_copy(sg_span
, sched_domain_span(child
));
7224 cpumask_set_cpu(i
, sg_span
);
7226 cpumask_or(covered
, covered
, sg_span
);
7228 sg
->sgp
= *per_cpu_ptr(sdd
->sgp
, cpumask_first(sg_span
));
7229 atomic_inc(&sg
->sgp
->ref
);
7231 if (cpumask_test_cpu(cpu
, sg_span
))
7241 sd
->groups
= groups
;
7246 free_sched_groups(first
, 0);
7251 static int get_group(int cpu
, struct sd_data
*sdd
, struct sched_group
**sg
)
7253 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, cpu
);
7254 struct sched_domain
*child
= sd
->child
;
7257 cpu
= cpumask_first(sched_domain_span(child
));
7260 *sg
= *per_cpu_ptr(sdd
->sg
, cpu
);
7261 (*sg
)->sgp
= *per_cpu_ptr(sdd
->sgp
, cpu
);
7262 atomic_set(&(*sg
)->sgp
->ref
, 1); /* for claim_allocations */
7269 * build_sched_groups will build a circular linked list of the groups
7270 * covered by the given span, and will set each group's ->cpumask correctly,
7271 * and ->cpu_power to 0.
7273 * Assumes the sched_domain tree is fully constructed
7276 build_sched_groups(struct sched_domain
*sd
, int cpu
)
7278 struct sched_group
*first
= NULL
, *last
= NULL
;
7279 struct sd_data
*sdd
= sd
->private;
7280 const struct cpumask
*span
= sched_domain_span(sd
);
7281 struct cpumask
*covered
;
7284 get_group(cpu
, sdd
, &sd
->groups
);
7285 atomic_inc(&sd
->groups
->ref
);
7287 if (cpu
!= cpumask_first(sched_domain_span(sd
)))
7290 lockdep_assert_held(&sched_domains_mutex
);
7291 covered
= sched_domains_tmpmask
;
7293 cpumask_clear(covered
);
7295 for_each_cpu(i
, span
) {
7296 struct sched_group
*sg
;
7297 int group
= get_group(i
, sdd
, &sg
);
7300 if (cpumask_test_cpu(i
, covered
))
7303 cpumask_clear(sched_group_cpus(sg
));
7306 for_each_cpu(j
, span
) {
7307 if (get_group(j
, sdd
, NULL
) != group
)
7310 cpumask_set_cpu(j
, covered
);
7311 cpumask_set_cpu(j
, sched_group_cpus(sg
));
7326 * Initialize sched groups cpu_power.
7328 * cpu_power indicates the capacity of sched group, which is used while
7329 * distributing the load between different sched groups in a sched domain.
7330 * Typically cpu_power for all the groups in a sched domain will be same unless
7331 * there are asymmetries in the topology. If there are asymmetries, group
7332 * having more cpu_power will pickup more load compared to the group having
7335 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
7337 struct sched_group
*sg
= sd
->groups
;
7339 WARN_ON(!sd
|| !sg
);
7342 sg
->group_weight
= cpumask_weight(sched_group_cpus(sg
));
7344 } while (sg
!= sd
->groups
);
7346 if (cpu
!= group_first_cpu(sg
))
7349 update_group_power(sd
, cpu
);
7353 * Initializers for schedule domains
7354 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7357 #ifdef CONFIG_SCHED_DEBUG
7358 # define SD_INIT_NAME(sd, type) sd->name = #type
7360 # define SD_INIT_NAME(sd, type) do { } while (0)
7363 #define SD_INIT_FUNC(type) \
7364 static noinline struct sched_domain * \
7365 sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
7367 struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
7368 *sd = SD_##type##_INIT; \
7369 SD_INIT_NAME(sd, type); \
7370 sd->private = &tl->data; \
7376 SD_INIT_FUNC(ALLNODES
)
7379 #ifdef CONFIG_SCHED_SMT
7380 SD_INIT_FUNC(SIBLING
)
7382 #ifdef CONFIG_SCHED_MC
7385 #ifdef CONFIG_SCHED_BOOK
7389 static int default_relax_domain_level
= -1;
7390 int sched_domain_level_max
;
7392 static int __init
setup_relax_domain_level(char *str
)
7396 val
= simple_strtoul(str
, NULL
, 0);
7397 if (val
< sched_domain_level_max
)
7398 default_relax_domain_level
= val
;
7402 __setup("relax_domain_level=", setup_relax_domain_level
);
7404 static void set_domain_attribute(struct sched_domain
*sd
,
7405 struct sched_domain_attr
*attr
)
7409 if (!attr
|| attr
->relax_domain_level
< 0) {
7410 if (default_relax_domain_level
< 0)
7413 request
= default_relax_domain_level
;
7415 request
= attr
->relax_domain_level
;
7416 if (request
< sd
->level
) {
7417 /* turn off idle balance on this domain */
7418 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
7420 /* turn on idle balance on this domain */
7421 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
7425 static void __sdt_free(const struct cpumask
*cpu_map
);
7426 static int __sdt_alloc(const struct cpumask
*cpu_map
);
7428 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
7429 const struct cpumask
*cpu_map
)
7433 if (!atomic_read(&d
->rd
->refcount
))
7434 free_rootdomain(&d
->rd
->rcu
); /* fall through */
7436 free_percpu(d
->sd
); /* fall through */
7438 __sdt_free(cpu_map
); /* fall through */
7444 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
7445 const struct cpumask
*cpu_map
)
7447 memset(d
, 0, sizeof(*d
));
7449 if (__sdt_alloc(cpu_map
))
7450 return sa_sd_storage
;
7451 d
->sd
= alloc_percpu(struct sched_domain
*);
7453 return sa_sd_storage
;
7454 d
->rd
= alloc_rootdomain();
7457 return sa_rootdomain
;
7461 * NULL the sd_data elements we've used to build the sched_domain and
7462 * sched_group structure so that the subsequent __free_domain_allocs()
7463 * will not free the data we're using.
7465 static void claim_allocations(int cpu
, struct sched_domain
*sd
)
7467 struct sd_data
*sdd
= sd
->private;
7469 WARN_ON_ONCE(*per_cpu_ptr(sdd
->sd
, cpu
) != sd
);
7470 *per_cpu_ptr(sdd
->sd
, cpu
) = NULL
;
7472 if (atomic_read(&(*per_cpu_ptr(sdd
->sg
, cpu
))->ref
))
7473 *per_cpu_ptr(sdd
->sg
, cpu
) = NULL
;
7475 if (atomic_read(&(*per_cpu_ptr(sdd
->sgp
, cpu
))->ref
))
7476 *per_cpu_ptr(sdd
->sgp
, cpu
) = NULL
;
7479 #ifdef CONFIG_SCHED_SMT
7480 static const struct cpumask
*cpu_smt_mask(int cpu
)
7482 return topology_thread_cpumask(cpu
);
7487 * Topology list, bottom-up.
7489 static struct sched_domain_topology_level default_topology
[] = {
7490 #ifdef CONFIG_SCHED_SMT
7491 { sd_init_SIBLING
, cpu_smt_mask
, },
7493 #ifdef CONFIG_SCHED_MC
7494 { sd_init_MC
, cpu_coregroup_mask
, },
7496 #ifdef CONFIG_SCHED_BOOK
7497 { sd_init_BOOK
, cpu_book_mask
, },
7499 { sd_init_CPU
, cpu_cpu_mask
, },
7501 { sd_init_NODE
, cpu_node_mask
, SDTL_OVERLAP
, },
7502 { sd_init_ALLNODES
, cpu_allnodes_mask
, },
7507 static struct sched_domain_topology_level
*sched_domain_topology
= default_topology
;
7509 static int __sdt_alloc(const struct cpumask
*cpu_map
)
7511 struct sched_domain_topology_level
*tl
;
7514 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
7515 struct sd_data
*sdd
= &tl
->data
;
7517 sdd
->sd
= alloc_percpu(struct sched_domain
*);
7521 sdd
->sg
= alloc_percpu(struct sched_group
*);
7525 sdd
->sgp
= alloc_percpu(struct sched_group_power
*);
7529 for_each_cpu(j
, cpu_map
) {
7530 struct sched_domain
*sd
;
7531 struct sched_group
*sg
;
7532 struct sched_group_power
*sgp
;
7534 sd
= kzalloc_node(sizeof(struct sched_domain
) + cpumask_size(),
7535 GFP_KERNEL
, cpu_to_node(j
));
7539 *per_cpu_ptr(sdd
->sd
, j
) = sd
;
7541 sg
= kzalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7542 GFP_KERNEL
, cpu_to_node(j
));
7546 *per_cpu_ptr(sdd
->sg
, j
) = sg
;
7548 sgp
= kzalloc_node(sizeof(struct sched_group_power
),
7549 GFP_KERNEL
, cpu_to_node(j
));
7553 *per_cpu_ptr(sdd
->sgp
, j
) = sgp
;
7560 static void __sdt_free(const struct cpumask
*cpu_map
)
7562 struct sched_domain_topology_level
*tl
;
7565 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
7566 struct sd_data
*sdd
= &tl
->data
;
7568 for_each_cpu(j
, cpu_map
) {
7569 struct sched_domain
*sd
= *per_cpu_ptr(sdd
->sd
, j
);
7570 if (sd
&& (sd
->flags
& SD_OVERLAP
))
7571 free_sched_groups(sd
->groups
, 0);
7572 kfree(*per_cpu_ptr(sdd
->sd
, j
));
7573 kfree(*per_cpu_ptr(sdd
->sg
, j
));
7574 kfree(*per_cpu_ptr(sdd
->sgp
, j
));
7576 free_percpu(sdd
->sd
);
7577 free_percpu(sdd
->sg
);
7578 free_percpu(sdd
->sgp
);
7582 struct sched_domain
*build_sched_domain(struct sched_domain_topology_level
*tl
,
7583 struct s_data
*d
, const struct cpumask
*cpu_map
,
7584 struct sched_domain_attr
*attr
, struct sched_domain
*child
,
7587 struct sched_domain
*sd
= tl
->init(tl
, cpu
);
7591 set_domain_attribute(sd
, attr
);
7592 cpumask_and(sched_domain_span(sd
), cpu_map
, tl
->mask(cpu
));
7594 sd
->level
= child
->level
+ 1;
7595 sched_domain_level_max
= max(sched_domain_level_max
, sd
->level
);
7604 * Build sched domains for a given set of cpus and attach the sched domains
7605 * to the individual cpus
7607 static int build_sched_domains(const struct cpumask
*cpu_map
,
7608 struct sched_domain_attr
*attr
)
7610 enum s_alloc alloc_state
= sa_none
;
7611 struct sched_domain
*sd
;
7613 int i
, ret
= -ENOMEM
;
7615 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
7616 if (alloc_state
!= sa_rootdomain
)
7619 /* Set up domains for cpus specified by the cpu_map. */
7620 for_each_cpu(i
, cpu_map
) {
7621 struct sched_domain_topology_level
*tl
;
7624 for (tl
= sched_domain_topology
; tl
->init
; tl
++) {
7625 sd
= build_sched_domain(tl
, &d
, cpu_map
, attr
, sd
, i
);
7626 if (tl
->flags
& SDTL_OVERLAP
|| sched_feat(FORCE_SD_OVERLAP
))
7627 sd
->flags
|= SD_OVERLAP
;
7628 if (cpumask_equal(cpu_map
, sched_domain_span(sd
)))
7635 *per_cpu_ptr(d
.sd
, i
) = sd
;
7638 /* Build the groups for the domains */
7639 for_each_cpu(i
, cpu_map
) {
7640 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
7641 sd
->span_weight
= cpumask_weight(sched_domain_span(sd
));
7642 if (sd
->flags
& SD_OVERLAP
) {
7643 if (build_overlap_sched_groups(sd
, i
))
7646 if (build_sched_groups(sd
, i
))
7652 /* Calculate CPU power for physical packages and nodes */
7653 for (i
= nr_cpumask_bits
-1; i
>= 0; i
--) {
7654 if (!cpumask_test_cpu(i
, cpu_map
))
7657 for (sd
= *per_cpu_ptr(d
.sd
, i
); sd
; sd
= sd
->parent
) {
7658 claim_allocations(i
, sd
);
7659 init_sched_groups_power(i
, sd
);
7663 /* Attach the domains */
7665 for_each_cpu(i
, cpu_map
) {
7666 sd
= *per_cpu_ptr(d
.sd
, i
);
7667 cpu_attach_domain(sd
, d
.rd
, i
);
7673 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
7677 static cpumask_var_t
*doms_cur
; /* current sched domains */
7678 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7679 static struct sched_domain_attr
*dattr_cur
;
7680 /* attribues of custom domains in 'doms_cur' */
7683 * Special case: If a kmalloc of a doms_cur partition (array of
7684 * cpumask) fails, then fallback to a single sched domain,
7685 * as determined by the single cpumask fallback_doms.
7687 static cpumask_var_t fallback_doms
;
7690 * arch_update_cpu_topology lets virtualized architectures update the
7691 * cpu core maps. It is supposed to return 1 if the topology changed
7692 * or 0 if it stayed the same.
7694 int __attribute__((weak
)) arch_update_cpu_topology(void)
7699 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
7702 cpumask_var_t
*doms
;
7704 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
7707 for (i
= 0; i
< ndoms
; i
++) {
7708 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
7709 free_sched_domains(doms
, i
);
7716 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
7719 for (i
= 0; i
< ndoms
; i
++)
7720 free_cpumask_var(doms
[i
]);
7725 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7726 * For now this just excludes isolated cpus, but could be used to
7727 * exclude other special cases in the future.
7729 static int init_sched_domains(const struct cpumask
*cpu_map
)
7733 arch_update_cpu_topology();
7735 doms_cur
= alloc_sched_domains(ndoms_cur
);
7737 doms_cur
= &fallback_doms
;
7738 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
7740 err
= build_sched_domains(doms_cur
[0], NULL
);
7741 register_sched_domain_sysctl();
7747 * Detach sched domains from a group of cpus specified in cpu_map
7748 * These cpus will now be attached to the NULL domain
7750 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7755 for_each_cpu(i
, cpu_map
)
7756 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7760 /* handle null as "default" */
7761 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7762 struct sched_domain_attr
*new, int idx_new
)
7764 struct sched_domain_attr tmp
;
7771 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7772 new ? (new + idx_new
) : &tmp
,
7773 sizeof(struct sched_domain_attr
));
7777 * Partition sched domains as specified by the 'ndoms_new'
7778 * cpumasks in the array doms_new[] of cpumasks. This compares
7779 * doms_new[] to the current sched domain partitioning, doms_cur[].
7780 * It destroys each deleted domain and builds each new domain.
7782 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7783 * The masks don't intersect (don't overlap.) We should setup one
7784 * sched domain for each mask. CPUs not in any of the cpumasks will
7785 * not be load balanced. If the same cpumask appears both in the
7786 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7789 * The passed in 'doms_new' should be allocated using
7790 * alloc_sched_domains. This routine takes ownership of it and will
7791 * free_sched_domains it when done with it. If the caller failed the
7792 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7793 * and partition_sched_domains() will fallback to the single partition
7794 * 'fallback_doms', it also forces the domains to be rebuilt.
7796 * If doms_new == NULL it will be replaced with cpu_online_mask.
7797 * ndoms_new == 0 is a special case for destroying existing domains,
7798 * and it will not create the default domain.
7800 * Call with hotplug lock held
7802 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
7803 struct sched_domain_attr
*dattr_new
)
7808 mutex_lock(&sched_domains_mutex
);
7810 /* always unregister in case we don't destroy any domains */
7811 unregister_sched_domain_sysctl();
7813 /* Let architecture update cpu core mappings. */
7814 new_topology
= arch_update_cpu_topology();
7816 n
= doms_new
? ndoms_new
: 0;
7818 /* Destroy deleted domains */
7819 for (i
= 0; i
< ndoms_cur
; i
++) {
7820 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7821 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
7822 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7825 /* no match - a current sched domain not in new doms_new[] */
7826 detach_destroy_domains(doms_cur
[i
]);
7831 if (doms_new
== NULL
) {
7833 doms_new
= &fallback_doms
;
7834 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
7835 WARN_ON_ONCE(dattr_new
);
7838 /* Build new domains */
7839 for (i
= 0; i
< ndoms_new
; i
++) {
7840 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
7841 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
7842 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7845 /* no match - add a new doms_new */
7846 build_sched_domains(doms_new
[i
], dattr_new
? dattr_new
+ i
: NULL
);
7851 /* Remember the new sched domains */
7852 if (doms_cur
!= &fallback_doms
)
7853 free_sched_domains(doms_cur
, ndoms_cur
);
7854 kfree(dattr_cur
); /* kfree(NULL) is safe */
7855 doms_cur
= doms_new
;
7856 dattr_cur
= dattr_new
;
7857 ndoms_cur
= ndoms_new
;
7859 register_sched_domain_sysctl();
7861 mutex_unlock(&sched_domains_mutex
);
7864 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7865 static void reinit_sched_domains(void)
7869 /* Destroy domains first to force the rebuild */
7870 partition_sched_domains(0, NULL
, NULL
);
7872 rebuild_sched_domains();
7876 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7878 unsigned int level
= 0;
7880 if (sscanf(buf
, "%u", &level
) != 1)
7884 * level is always be positive so don't check for
7885 * level < POWERSAVINGS_BALANCE_NONE which is 0
7886 * What happens on 0 or 1 byte write,
7887 * need to check for count as well?
7890 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
7894 sched_smt_power_savings
= level
;
7896 sched_mc_power_savings
= level
;
7898 reinit_sched_domains();
7903 #ifdef CONFIG_SCHED_MC
7904 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
7905 struct sysdev_class_attribute
*attr
,
7908 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7910 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
7911 struct sysdev_class_attribute
*attr
,
7912 const char *buf
, size_t count
)
7914 return sched_power_savings_store(buf
, count
, 0);
7916 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
7917 sched_mc_power_savings_show
,
7918 sched_mc_power_savings_store
);
7921 #ifdef CONFIG_SCHED_SMT
7922 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
7923 struct sysdev_class_attribute
*attr
,
7926 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7928 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
7929 struct sysdev_class_attribute
*attr
,
7930 const char *buf
, size_t count
)
7932 return sched_power_savings_store(buf
, count
, 1);
7934 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
7935 sched_smt_power_savings_show
,
7936 sched_smt_power_savings_store
);
7939 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7943 #ifdef CONFIG_SCHED_SMT
7945 err
= sysfs_create_file(&cls
->kset
.kobj
,
7946 &attr_sched_smt_power_savings
.attr
);
7948 #ifdef CONFIG_SCHED_MC
7949 if (!err
&& mc_capable())
7950 err
= sysfs_create_file(&cls
->kset
.kobj
,
7951 &attr_sched_mc_power_savings
.attr
);
7955 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7958 * Update cpusets according to cpu_active mask. If cpusets are
7959 * disabled, cpuset_update_active_cpus() becomes a simple wrapper
7960 * around partition_sched_domains().
7962 static int cpuset_cpu_active(struct notifier_block
*nfb
, unsigned long action
,
7965 switch (action
& ~CPU_TASKS_FROZEN
) {
7967 case CPU_DOWN_FAILED
:
7968 cpuset_update_active_cpus();
7975 static int cpuset_cpu_inactive(struct notifier_block
*nfb
, unsigned long action
,
7978 switch (action
& ~CPU_TASKS_FROZEN
) {
7979 case CPU_DOWN_PREPARE
:
7980 cpuset_update_active_cpus();
7987 static int update_runtime(struct notifier_block
*nfb
,
7988 unsigned long action
, void *hcpu
)
7990 int cpu
= (int)(long)hcpu
;
7993 case CPU_DOWN_PREPARE
:
7994 case CPU_DOWN_PREPARE_FROZEN
:
7995 disable_runtime(cpu_rq(cpu
));
7998 case CPU_DOWN_FAILED
:
7999 case CPU_DOWN_FAILED_FROZEN
:
8001 case CPU_ONLINE_FROZEN
:
8002 enable_runtime(cpu_rq(cpu
));
8010 void __init
sched_init_smp(void)
8012 cpumask_var_t non_isolated_cpus
;
8014 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
8015 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
8018 mutex_lock(&sched_domains_mutex
);
8019 init_sched_domains(cpu_active_mask
);
8020 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
8021 if (cpumask_empty(non_isolated_cpus
))
8022 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
8023 mutex_unlock(&sched_domains_mutex
);
8026 hotcpu_notifier(cpuset_cpu_active
, CPU_PRI_CPUSET_ACTIVE
);
8027 hotcpu_notifier(cpuset_cpu_inactive
, CPU_PRI_CPUSET_INACTIVE
);
8029 /* RT runtime code needs to handle some hotplug events */
8030 hotcpu_notifier(update_runtime
, 0);
8034 /* Move init over to a non-isolated CPU */
8035 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
8037 sched_init_granularity();
8038 free_cpumask_var(non_isolated_cpus
);
8040 init_sched_rt_class();
8043 void __init
sched_init_smp(void)
8045 sched_init_granularity();
8047 #endif /* CONFIG_SMP */
8049 const_debug
unsigned int sysctl_timer_migration
= 1;
8051 int in_sched_functions(unsigned long addr
)
8053 return in_lock_functions(addr
) ||
8054 (addr
>= (unsigned long)__sched_text_start
8055 && addr
< (unsigned long)__sched_text_end
);
8058 static void init_cfs_rq(struct cfs_rq
*cfs_rq
)
8060 cfs_rq
->tasks_timeline
= RB_ROOT
;
8061 INIT_LIST_HEAD(&cfs_rq
->tasks
);
8062 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
8063 #ifndef CONFIG_64BIT
8064 cfs_rq
->min_vruntime_copy
= cfs_rq
->min_vruntime
;
8068 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
8070 struct rt_prio_array
*array
;
8073 array
= &rt_rq
->active
;
8074 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
8075 INIT_LIST_HEAD(array
->queue
+ i
);
8076 __clear_bit(i
, array
->bitmap
);
8078 /* delimiter for bitsearch: */
8079 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
8081 #if defined CONFIG_SMP
8082 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
8083 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
8084 rt_rq
->rt_nr_migratory
= 0;
8085 rt_rq
->overloaded
= 0;
8086 plist_head_init(&rt_rq
->pushable_tasks
);
8090 rt_rq
->rt_throttled
= 0;
8091 rt_rq
->rt_runtime
= 0;
8092 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
8095 #ifdef CONFIG_FAIR_GROUP_SCHED
8096 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
8097 struct sched_entity
*se
, int cpu
,
8098 struct sched_entity
*parent
)
8100 struct rq
*rq
= cpu_rq(cpu
);
8105 /* allow initial update_cfs_load() to truncate */
8106 cfs_rq
->load_stamp
= 1;
8108 init_cfs_rq_runtime(cfs_rq
);
8110 tg
->cfs_rq
[cpu
] = cfs_rq
;
8113 /* se could be NULL for root_task_group */
8118 se
->cfs_rq
= &rq
->cfs
;
8120 se
->cfs_rq
= parent
->my_q
;
8123 update_load_set(&se
->load
, 0);
8124 se
->parent
= parent
;
8128 #ifdef CONFIG_RT_GROUP_SCHED
8129 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
8130 struct sched_rt_entity
*rt_se
, int cpu
,
8131 struct sched_rt_entity
*parent
)
8133 struct rq
*rq
= cpu_rq(cpu
);
8135 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
8136 rt_rq
->rt_nr_boosted
= 0;
8140 tg
->rt_rq
[cpu
] = rt_rq
;
8141 tg
->rt_se
[cpu
] = rt_se
;
8147 rt_se
->rt_rq
= &rq
->rt
;
8149 rt_se
->rt_rq
= parent
->my_q
;
8151 rt_se
->my_q
= rt_rq
;
8152 rt_se
->parent
= parent
;
8153 INIT_LIST_HEAD(&rt_se
->run_list
);
8157 void __init
sched_init(void)
8160 unsigned long alloc_size
= 0, ptr
;
8162 #ifdef CONFIG_FAIR_GROUP_SCHED
8163 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8165 #ifdef CONFIG_RT_GROUP_SCHED
8166 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8168 #ifdef CONFIG_CPUMASK_OFFSTACK
8169 alloc_size
+= num_possible_cpus() * cpumask_size();
8172 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
8174 #ifdef CONFIG_FAIR_GROUP_SCHED
8175 root_task_group
.se
= (struct sched_entity
**)ptr
;
8176 ptr
+= nr_cpu_ids
* sizeof(void **);
8178 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8179 ptr
+= nr_cpu_ids
* sizeof(void **);
8181 #endif /* CONFIG_FAIR_GROUP_SCHED */
8182 #ifdef CONFIG_RT_GROUP_SCHED
8183 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8184 ptr
+= nr_cpu_ids
* sizeof(void **);
8186 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8187 ptr
+= nr_cpu_ids
* sizeof(void **);
8189 #endif /* CONFIG_RT_GROUP_SCHED */
8190 #ifdef CONFIG_CPUMASK_OFFSTACK
8191 for_each_possible_cpu(i
) {
8192 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
8193 ptr
+= cpumask_size();
8195 #endif /* CONFIG_CPUMASK_OFFSTACK */
8199 init_defrootdomain();
8202 init_rt_bandwidth(&def_rt_bandwidth
,
8203 global_rt_period(), global_rt_runtime());
8205 #ifdef CONFIG_RT_GROUP_SCHED
8206 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
8207 global_rt_period(), global_rt_runtime());
8208 #endif /* CONFIG_RT_GROUP_SCHED */
8210 #ifdef CONFIG_CGROUP_SCHED
8211 list_add(&root_task_group
.list
, &task_groups
);
8212 INIT_LIST_HEAD(&root_task_group
.children
);
8213 autogroup_init(&init_task
);
8214 #endif /* CONFIG_CGROUP_SCHED */
8216 for_each_possible_cpu(i
) {
8220 raw_spin_lock_init(&rq
->lock
);
8222 rq
->calc_load_active
= 0;
8223 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
8224 init_cfs_rq(&rq
->cfs
);
8225 init_rt_rq(&rq
->rt
, rq
);
8226 #ifdef CONFIG_FAIR_GROUP_SCHED
8227 root_task_group
.shares
= root_task_group_load
;
8228 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
8230 * How much cpu bandwidth does root_task_group get?
8232 * In case of task-groups formed thr' the cgroup filesystem, it
8233 * gets 100% of the cpu resources in the system. This overall
8234 * system cpu resource is divided among the tasks of
8235 * root_task_group and its child task-groups in a fair manner,
8236 * based on each entity's (task or task-group's) weight
8237 * (se->load.weight).
8239 * In other words, if root_task_group has 10 tasks of weight
8240 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8241 * then A0's share of the cpu resource is:
8243 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8245 * We achieve this by letting root_task_group's tasks sit
8246 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
8248 init_cfs_bandwidth(&root_task_group
.cfs_bandwidth
);
8249 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, NULL
);
8250 #endif /* CONFIG_FAIR_GROUP_SCHED */
8252 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
8253 #ifdef CONFIG_RT_GROUP_SCHED
8254 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
8255 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, NULL
);
8258 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
8259 rq
->cpu_load
[j
] = 0;
8261 rq
->last_load_update_tick
= jiffies
;
8266 rq
->cpu_power
= SCHED_POWER_SCALE
;
8267 rq
->post_schedule
= 0;
8268 rq
->active_balance
= 0;
8269 rq
->next_balance
= jiffies
;
8274 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
8275 rq_attach_root(rq
, &def_root_domain
);
8277 rq
->nohz_balance_kick
= 0;
8278 init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb
, i
));
8282 atomic_set(&rq
->nr_iowait
, 0);
8285 set_load_weight(&init_task
);
8287 #ifdef CONFIG_PREEMPT_NOTIFIERS
8288 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
8292 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
8295 #ifdef CONFIG_RT_MUTEXES
8296 plist_head_init(&init_task
.pi_waiters
);
8300 * The boot idle thread does lazy MMU switching as well:
8302 atomic_inc(&init_mm
.mm_count
);
8303 enter_lazy_tlb(&init_mm
, current
);
8306 * Make us the idle thread. Technically, schedule() should not be
8307 * called from this thread, however somewhere below it might be,
8308 * but because we are the idle thread, we just pick up running again
8309 * when this runqueue becomes "idle".
8311 init_idle(current
, smp_processor_id());
8313 calc_load_update
= jiffies
+ LOAD_FREQ
;
8316 * During early bootup we pretend to be a normal task:
8318 current
->sched_class
= &fair_sched_class
;
8320 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
8321 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
8323 zalloc_cpumask_var(&sched_domains_tmpmask
, GFP_NOWAIT
);
8325 zalloc_cpumask_var(&nohz
.idle_cpus_mask
, GFP_NOWAIT
);
8326 alloc_cpumask_var(&nohz
.grp_idle_mask
, GFP_NOWAIT
);
8327 atomic_set(&nohz
.load_balancer
, nr_cpu_ids
);
8328 atomic_set(&nohz
.first_pick_cpu
, nr_cpu_ids
);
8329 atomic_set(&nohz
.second_pick_cpu
, nr_cpu_ids
);
8331 /* May be allocated at isolcpus cmdline parse time */
8332 if (cpu_isolated_map
== NULL
)
8333 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
8336 scheduler_running
= 1;
8339 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
8340 static inline int preempt_count_equals(int preempt_offset
)
8342 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
8344 return (nested
== preempt_offset
);
8347 void __might_sleep(const char *file
, int line
, int preempt_offset
)
8349 static unsigned long prev_jiffy
; /* ratelimiting */
8351 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
8352 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
8354 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
8356 prev_jiffy
= jiffies
;
8359 "BUG: sleeping function called from invalid context at %s:%d\n",
8362 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
8363 in_atomic(), irqs_disabled(),
8364 current
->pid
, current
->comm
);
8366 debug_show_held_locks(current
);
8367 if (irqs_disabled())
8368 print_irqtrace_events(current
);
8371 EXPORT_SYMBOL(__might_sleep
);
8374 #ifdef CONFIG_MAGIC_SYSRQ
8375 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
8377 const struct sched_class
*prev_class
= p
->sched_class
;
8378 int old_prio
= p
->prio
;
8383 deactivate_task(rq
, p
, 0);
8384 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
8386 activate_task(rq
, p
, 0);
8387 resched_task(rq
->curr
);
8390 check_class_changed(rq
, p
, prev_class
, old_prio
);
8393 void normalize_rt_tasks(void)
8395 struct task_struct
*g
, *p
;
8396 unsigned long flags
;
8399 read_lock_irqsave(&tasklist_lock
, flags
);
8400 do_each_thread(g
, p
) {
8402 * Only normalize user tasks:
8407 p
->se
.exec_start
= 0;
8408 #ifdef CONFIG_SCHEDSTATS
8409 p
->se
.statistics
.wait_start
= 0;
8410 p
->se
.statistics
.sleep_start
= 0;
8411 p
->se
.statistics
.block_start
= 0;
8416 * Renice negative nice level userspace
8419 if (TASK_NICE(p
) < 0 && p
->mm
)
8420 set_user_nice(p
, 0);
8424 raw_spin_lock(&p
->pi_lock
);
8425 rq
= __task_rq_lock(p
);
8427 normalize_task(rq
, p
);
8429 __task_rq_unlock(rq
);
8430 raw_spin_unlock(&p
->pi_lock
);
8431 } while_each_thread(g
, p
);
8433 read_unlock_irqrestore(&tasklist_lock
, flags
);
8436 #endif /* CONFIG_MAGIC_SYSRQ */
8438 #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
8440 * These functions are only useful for the IA64 MCA handling, or kdb.
8442 * They can only be called when the whole system has been
8443 * stopped - every CPU needs to be quiescent, and no scheduling
8444 * activity can take place. Using them for anything else would
8445 * be a serious bug, and as a result, they aren't even visible
8446 * under any other configuration.
8450 * curr_task - return the current task for a given cpu.
8451 * @cpu: the processor in question.
8453 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8455 struct task_struct
*curr_task(int cpu
)
8457 return cpu_curr(cpu
);
8460 #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
8464 * set_curr_task - set the current task for a given cpu.
8465 * @cpu: the processor in question.
8466 * @p: the task pointer to set.
8468 * Description: This function must only be used when non-maskable interrupts
8469 * are serviced on a separate stack. It allows the architecture to switch the
8470 * notion of the current task on a cpu in a non-blocking manner. This function
8471 * must be called with all CPU's synchronized, and interrupts disabled, the
8472 * and caller must save the original value of the current task (see
8473 * curr_task() above) and restore that value before reenabling interrupts and
8474 * re-starting the system.
8476 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8478 void set_curr_task(int cpu
, struct task_struct
*p
)
8485 #ifdef CONFIG_FAIR_GROUP_SCHED
8486 static void free_fair_sched_group(struct task_group
*tg
)
8490 destroy_cfs_bandwidth(tg_cfs_bandwidth(tg
));
8492 for_each_possible_cpu(i
) {
8494 kfree(tg
->cfs_rq
[i
]);
8504 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8506 struct cfs_rq
*cfs_rq
;
8507 struct sched_entity
*se
;
8510 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8513 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8517 tg
->shares
= NICE_0_LOAD
;
8519 init_cfs_bandwidth(tg_cfs_bandwidth(tg
));
8521 for_each_possible_cpu(i
) {
8522 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
8523 GFP_KERNEL
, cpu_to_node(i
));
8527 se
= kzalloc_node(sizeof(struct sched_entity
),
8528 GFP_KERNEL
, cpu_to_node(i
));
8532 init_cfs_rq(cfs_rq
);
8533 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, parent
->se
[i
]);
8544 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8546 struct rq
*rq
= cpu_rq(cpu
);
8547 unsigned long flags
;
8550 * Only empty task groups can be destroyed; so we can speculatively
8551 * check on_list without danger of it being re-added.
8553 if (!tg
->cfs_rq
[cpu
]->on_list
)
8556 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8557 list_del_leaf_cfs_rq(tg
->cfs_rq
[cpu
]);
8558 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8560 #else /* !CONFIG_FAIR_GROUP_SCHED */
8561 static inline void free_fair_sched_group(struct task_group
*tg
)
8566 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8571 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8574 #endif /* CONFIG_FAIR_GROUP_SCHED */
8576 #ifdef CONFIG_RT_GROUP_SCHED
8577 static void free_rt_sched_group(struct task_group
*tg
)
8582 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8584 for_each_possible_cpu(i
) {
8586 kfree(tg
->rt_rq
[i
]);
8588 kfree(tg
->rt_se
[i
]);
8596 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8598 struct rt_rq
*rt_rq
;
8599 struct sched_rt_entity
*rt_se
;
8602 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8605 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8609 init_rt_bandwidth(&tg
->rt_bandwidth
,
8610 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8612 for_each_possible_cpu(i
) {
8613 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8614 GFP_KERNEL
, cpu_to_node(i
));
8618 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8619 GFP_KERNEL
, cpu_to_node(i
));
8623 init_rt_rq(rt_rq
, cpu_rq(i
));
8624 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8625 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, parent
->rt_se
[i
]);
8635 #else /* !CONFIG_RT_GROUP_SCHED */
8636 static inline void free_rt_sched_group(struct task_group
*tg
)
8641 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8645 #endif /* CONFIG_RT_GROUP_SCHED */
8647 #ifdef CONFIG_CGROUP_SCHED
8648 static void free_sched_group(struct task_group
*tg
)
8650 free_fair_sched_group(tg
);
8651 free_rt_sched_group(tg
);
8656 /* allocate runqueue etc for a new task group */
8657 struct task_group
*sched_create_group(struct task_group
*parent
)
8659 struct task_group
*tg
;
8660 unsigned long flags
;
8662 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8664 return ERR_PTR(-ENOMEM
);
8666 if (!alloc_fair_sched_group(tg
, parent
))
8669 if (!alloc_rt_sched_group(tg
, parent
))
8672 spin_lock_irqsave(&task_group_lock
, flags
);
8673 list_add_rcu(&tg
->list
, &task_groups
);
8675 WARN_ON(!parent
); /* root should already exist */
8677 tg
->parent
= parent
;
8678 INIT_LIST_HEAD(&tg
->children
);
8679 list_add_rcu(&tg
->siblings
, &parent
->children
);
8680 spin_unlock_irqrestore(&task_group_lock
, flags
);
8685 free_sched_group(tg
);
8686 return ERR_PTR(-ENOMEM
);
8689 /* rcu callback to free various structures associated with a task group */
8690 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8692 /* now it should be safe to free those cfs_rqs */
8693 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8696 /* Destroy runqueue etc associated with a task group */
8697 void sched_destroy_group(struct task_group
*tg
)
8699 unsigned long flags
;
8702 /* end participation in shares distribution */
8703 for_each_possible_cpu(i
)
8704 unregister_fair_sched_group(tg
, i
);
8706 spin_lock_irqsave(&task_group_lock
, flags
);
8707 list_del_rcu(&tg
->list
);
8708 list_del_rcu(&tg
->siblings
);
8709 spin_unlock_irqrestore(&task_group_lock
, flags
);
8711 /* wait for possible concurrent references to cfs_rqs complete */
8712 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8715 /* change task's runqueue when it moves between groups.
8716 * The caller of this function should have put the task in its new group
8717 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8718 * reflect its new group.
8720 void sched_move_task(struct task_struct
*tsk
)
8723 unsigned long flags
;
8726 rq
= task_rq_lock(tsk
, &flags
);
8728 running
= task_current(rq
, tsk
);
8732 dequeue_task(rq
, tsk
, 0);
8733 if (unlikely(running
))
8734 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8736 #ifdef CONFIG_FAIR_GROUP_SCHED
8737 if (tsk
->sched_class
->task_move_group
)
8738 tsk
->sched_class
->task_move_group(tsk
, on_rq
);
8741 set_task_rq(tsk
, task_cpu(tsk
));
8743 if (unlikely(running
))
8744 tsk
->sched_class
->set_curr_task(rq
);
8746 enqueue_task(rq
, tsk
, 0);
8748 task_rq_unlock(rq
, tsk
, &flags
);
8750 #endif /* CONFIG_CGROUP_SCHED */
8752 #ifdef CONFIG_FAIR_GROUP_SCHED
8753 static DEFINE_MUTEX(shares_mutex
);
8755 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8758 unsigned long flags
;
8761 * We can't change the weight of the root cgroup.
8766 shares
= clamp(shares
, scale_load(MIN_SHARES
), scale_load(MAX_SHARES
));
8768 mutex_lock(&shares_mutex
);
8769 if (tg
->shares
== shares
)
8772 tg
->shares
= shares
;
8773 for_each_possible_cpu(i
) {
8774 struct rq
*rq
= cpu_rq(i
);
8775 struct sched_entity
*se
;
8778 /* Propagate contribution to hierarchy */
8779 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8780 for_each_sched_entity(se
)
8781 update_cfs_shares(group_cfs_rq(se
));
8782 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8786 mutex_unlock(&shares_mutex
);
8790 unsigned long sched_group_shares(struct task_group
*tg
)
8796 #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH)
8797 static unsigned long to_ratio(u64 period
, u64 runtime
)
8799 if (runtime
== RUNTIME_INF
)
8802 return div64_u64(runtime
<< 20, period
);
8806 #ifdef CONFIG_RT_GROUP_SCHED
8808 * Ensure that the real time constraints are schedulable.
8810 static DEFINE_MUTEX(rt_constraints_mutex
);
8812 /* Must be called with tasklist_lock held */
8813 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8815 struct task_struct
*g
, *p
;
8817 do_each_thread(g
, p
) {
8818 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8820 } while_each_thread(g
, p
);
8825 struct rt_schedulable_data
{
8826 struct task_group
*tg
;
8831 static int tg_rt_schedulable(struct task_group
*tg
, void *data
)
8833 struct rt_schedulable_data
*d
= data
;
8834 struct task_group
*child
;
8835 unsigned long total
, sum
= 0;
8836 u64 period
, runtime
;
8838 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8839 runtime
= tg
->rt_bandwidth
.rt_runtime
;
8842 period
= d
->rt_period
;
8843 runtime
= d
->rt_runtime
;
8847 * Cannot have more runtime than the period.
8849 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8853 * Ensure we don't starve existing RT tasks.
8855 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
8858 total
= to_ratio(period
, runtime
);
8861 * Nobody can have more than the global setting allows.
8863 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
8867 * The sum of our children's runtime should not exceed our own.
8869 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
8870 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
8871 runtime
= child
->rt_bandwidth
.rt_runtime
;
8873 if (child
== d
->tg
) {
8874 period
= d
->rt_period
;
8875 runtime
= d
->rt_runtime
;
8878 sum
+= to_ratio(period
, runtime
);
8887 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8891 struct rt_schedulable_data data
= {
8893 .rt_period
= period
,
8894 .rt_runtime
= runtime
,
8898 ret
= walk_tg_tree(tg_rt_schedulable
, tg_nop
, &data
);
8904 static int tg_set_rt_bandwidth(struct task_group
*tg
,
8905 u64 rt_period
, u64 rt_runtime
)
8909 mutex_lock(&rt_constraints_mutex
);
8910 read_lock(&tasklist_lock
);
8911 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
8915 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8916 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8917 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8919 for_each_possible_cpu(i
) {
8920 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8922 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8923 rt_rq
->rt_runtime
= rt_runtime
;
8924 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8926 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8928 read_unlock(&tasklist_lock
);
8929 mutex_unlock(&rt_constraints_mutex
);
8934 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8936 u64 rt_runtime
, rt_period
;
8938 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8939 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8940 if (rt_runtime_us
< 0)
8941 rt_runtime
= RUNTIME_INF
;
8943 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
8946 long sched_group_rt_runtime(struct task_group
*tg
)
8950 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8953 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8954 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8955 return rt_runtime_us
;
8958 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8960 u64 rt_runtime
, rt_period
;
8962 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8963 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8968 return tg_set_rt_bandwidth(tg
, rt_period
, rt_runtime
);
8971 long sched_group_rt_period(struct task_group
*tg
)
8975 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8976 do_div(rt_period_us
, NSEC_PER_USEC
);
8977 return rt_period_us
;
8980 static int sched_rt_global_constraints(void)
8982 u64 runtime
, period
;
8985 if (sysctl_sched_rt_period
<= 0)
8988 runtime
= global_rt_runtime();
8989 period
= global_rt_period();
8992 * Sanity check on the sysctl variables.
8994 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8997 mutex_lock(&rt_constraints_mutex
);
8998 read_lock(&tasklist_lock
);
8999 ret
= __rt_schedulable(NULL
, 0, 0);
9000 read_unlock(&tasklist_lock
);
9001 mutex_unlock(&rt_constraints_mutex
);
9006 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
9008 /* Don't accept realtime tasks when there is no way for them to run */
9009 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
9015 #else /* !CONFIG_RT_GROUP_SCHED */
9016 static int sched_rt_global_constraints(void)
9018 unsigned long flags
;
9021 if (sysctl_sched_rt_period
<= 0)
9025 * There's always some RT tasks in the root group
9026 * -- migration, kstopmachine etc..
9028 if (sysctl_sched_rt_runtime
== 0)
9031 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9032 for_each_possible_cpu(i
) {
9033 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
9035 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
9036 rt_rq
->rt_runtime
= global_rt_runtime();
9037 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
9039 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9043 #endif /* CONFIG_RT_GROUP_SCHED */
9045 int sched_rt_handler(struct ctl_table
*table
, int write
,
9046 void __user
*buffer
, size_t *lenp
,
9050 int old_period
, old_runtime
;
9051 static DEFINE_MUTEX(mutex
);
9054 old_period
= sysctl_sched_rt_period
;
9055 old_runtime
= sysctl_sched_rt_runtime
;
9057 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
9059 if (!ret
&& write
) {
9060 ret
= sched_rt_global_constraints();
9062 sysctl_sched_rt_period
= old_period
;
9063 sysctl_sched_rt_runtime
= old_runtime
;
9065 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
9066 def_rt_bandwidth
.rt_period
=
9067 ns_to_ktime(global_rt_period());
9070 mutex_unlock(&mutex
);
9075 #ifdef CONFIG_CGROUP_SCHED
9077 /* return corresponding task_group object of a cgroup */
9078 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
9080 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
9081 struct task_group
, css
);
9084 static struct cgroup_subsys_state
*
9085 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9087 struct task_group
*tg
, *parent
;
9089 if (!cgrp
->parent
) {
9090 /* This is early initialization for the top cgroup */
9091 return &root_task_group
.css
;
9094 parent
= cgroup_tg(cgrp
->parent
);
9095 tg
= sched_create_group(parent
);
9097 return ERR_PTR(-ENOMEM
);
9103 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9105 struct task_group
*tg
= cgroup_tg(cgrp
);
9107 sched_destroy_group(tg
);
9111 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
9113 #ifdef CONFIG_RT_GROUP_SCHED
9114 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
9117 /* We don't support RT-tasks being in separate groups */
9118 if (tsk
->sched_class
!= &fair_sched_class
)
9125 cpu_cgroup_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
9127 sched_move_task(tsk
);
9131 cpu_cgroup_exit(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9132 struct cgroup
*old_cgrp
, struct task_struct
*task
)
9135 * cgroup_exit() is called in the copy_process() failure path.
9136 * Ignore this case since the task hasn't ran yet, this avoids
9137 * trying to poke a half freed task state from generic code.
9139 if (!(task
->flags
& PF_EXITING
))
9142 sched_move_task(task
);
9145 #ifdef CONFIG_FAIR_GROUP_SCHED
9146 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9149 return sched_group_set_shares(cgroup_tg(cgrp
), scale_load(shareval
));
9152 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
9154 struct task_group
*tg
= cgroup_tg(cgrp
);
9156 return (u64
) scale_load_down(tg
->shares
);
9159 #ifdef CONFIG_CFS_BANDWIDTH
9160 static DEFINE_MUTEX(cfs_constraints_mutex
);
9162 const u64 max_cfs_quota_period
= 1 * NSEC_PER_SEC
; /* 1s */
9163 const u64 min_cfs_quota_period
= 1 * NSEC_PER_MSEC
; /* 1ms */
9165 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
);
9167 static int tg_set_cfs_bandwidth(struct task_group
*tg
, u64 period
, u64 quota
)
9169 int i
, ret
= 0, runtime_enabled
;
9170 struct cfs_bandwidth
*cfs_b
= tg_cfs_bandwidth(tg
);
9172 if (tg
== &root_task_group
)
9176 * Ensure we have at some amount of bandwidth every period. This is
9177 * to prevent reaching a state of large arrears when throttled via
9178 * entity_tick() resulting in prolonged exit starvation.
9180 if (quota
< min_cfs_quota_period
|| period
< min_cfs_quota_period
)
9184 * Likewise, bound things on the otherside by preventing insane quota
9185 * periods. This also allows us to normalize in computing quota
9188 if (period
> max_cfs_quota_period
)
9191 mutex_lock(&cfs_constraints_mutex
);
9192 ret
= __cfs_schedulable(tg
, period
, quota
);
9196 runtime_enabled
= quota
!= RUNTIME_INF
;
9197 raw_spin_lock_irq(&cfs_b
->lock
);
9198 cfs_b
->period
= ns_to_ktime(period
);
9199 cfs_b
->quota
= quota
;
9201 __refill_cfs_bandwidth_runtime(cfs_b
);
9202 /* restart the period timer (if active) to handle new period expiry */
9203 if (runtime_enabled
&& cfs_b
->timer_active
) {
9204 /* force a reprogram */
9205 cfs_b
->timer_active
= 0;
9206 __start_cfs_bandwidth(cfs_b
);
9208 raw_spin_unlock_irq(&cfs_b
->lock
);
9210 for_each_possible_cpu(i
) {
9211 struct cfs_rq
*cfs_rq
= tg
->cfs_rq
[i
];
9212 struct rq
*rq
= rq_of(cfs_rq
);
9214 raw_spin_lock_irq(&rq
->lock
);
9215 cfs_rq
->runtime_enabled
= runtime_enabled
;
9216 cfs_rq
->runtime_remaining
= 0;
9218 if (cfs_rq_throttled(cfs_rq
))
9219 unthrottle_cfs_rq(cfs_rq
);
9220 raw_spin_unlock_irq(&rq
->lock
);
9223 mutex_unlock(&cfs_constraints_mutex
);
9228 int tg_set_cfs_quota(struct task_group
*tg
, long cfs_quota_us
)
9232 period
= ktime_to_ns(tg_cfs_bandwidth(tg
)->period
);
9233 if (cfs_quota_us
< 0)
9234 quota
= RUNTIME_INF
;
9236 quota
= (u64
)cfs_quota_us
* NSEC_PER_USEC
;
9238 return tg_set_cfs_bandwidth(tg
, period
, quota
);
9241 long tg_get_cfs_quota(struct task_group
*tg
)
9245 if (tg_cfs_bandwidth(tg
)->quota
== RUNTIME_INF
)
9248 quota_us
= tg_cfs_bandwidth(tg
)->quota
;
9249 do_div(quota_us
, NSEC_PER_USEC
);
9254 int tg_set_cfs_period(struct task_group
*tg
, long cfs_period_us
)
9258 period
= (u64
)cfs_period_us
* NSEC_PER_USEC
;
9259 quota
= tg_cfs_bandwidth(tg
)->quota
;
9264 return tg_set_cfs_bandwidth(tg
, period
, quota
);
9267 long tg_get_cfs_period(struct task_group
*tg
)
9271 cfs_period_us
= ktime_to_ns(tg_cfs_bandwidth(tg
)->period
);
9272 do_div(cfs_period_us
, NSEC_PER_USEC
);
9274 return cfs_period_us
;
9277 static s64
cpu_cfs_quota_read_s64(struct cgroup
*cgrp
, struct cftype
*cft
)
9279 return tg_get_cfs_quota(cgroup_tg(cgrp
));
9282 static int cpu_cfs_quota_write_s64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9285 return tg_set_cfs_quota(cgroup_tg(cgrp
), cfs_quota_us
);
9288 static u64
cpu_cfs_period_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
9290 return tg_get_cfs_period(cgroup_tg(cgrp
));
9293 static int cpu_cfs_period_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9296 return tg_set_cfs_period(cgroup_tg(cgrp
), cfs_period_us
);
9299 struct cfs_schedulable_data
{
9300 struct task_group
*tg
;
9305 * normalize group quota/period to be quota/max_period
9306 * note: units are usecs
9308 static u64
normalize_cfs_quota(struct task_group
*tg
,
9309 struct cfs_schedulable_data
*d
)
9317 period
= tg_get_cfs_period(tg
);
9318 quota
= tg_get_cfs_quota(tg
);
9321 /* note: these should typically be equivalent */
9322 if (quota
== RUNTIME_INF
|| quota
== -1)
9325 return to_ratio(period
, quota
);
9328 static int tg_cfs_schedulable_down(struct task_group
*tg
, void *data
)
9330 struct cfs_schedulable_data
*d
= data
;
9331 struct cfs_bandwidth
*cfs_b
= tg_cfs_bandwidth(tg
);
9332 s64 quota
= 0, parent_quota
= -1;
9335 quota
= RUNTIME_INF
;
9337 struct cfs_bandwidth
*parent_b
= tg_cfs_bandwidth(tg
->parent
);
9339 quota
= normalize_cfs_quota(tg
, d
);
9340 parent_quota
= parent_b
->hierarchal_quota
;
9343 * ensure max(child_quota) <= parent_quota, inherit when no
9346 if (quota
== RUNTIME_INF
)
9347 quota
= parent_quota
;
9348 else if (parent_quota
!= RUNTIME_INF
&& quota
> parent_quota
)
9351 cfs_b
->hierarchal_quota
= quota
;
9356 static int __cfs_schedulable(struct task_group
*tg
, u64 period
, u64 quota
)
9359 struct cfs_schedulable_data data
= {
9365 if (quota
!= RUNTIME_INF
) {
9366 do_div(data
.period
, NSEC_PER_USEC
);
9367 do_div(data
.quota
, NSEC_PER_USEC
);
9371 ret
= walk_tg_tree(tg_cfs_schedulable_down
, tg_nop
, &data
);
9377 static int cpu_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
9378 struct cgroup_map_cb
*cb
)
9380 struct task_group
*tg
= cgroup_tg(cgrp
);
9381 struct cfs_bandwidth
*cfs_b
= tg_cfs_bandwidth(tg
);
9383 cb
->fill(cb
, "nr_periods", cfs_b
->nr_periods
);
9384 cb
->fill(cb
, "nr_throttled", cfs_b
->nr_throttled
);
9385 cb
->fill(cb
, "throttled_time", cfs_b
->throttled_time
);
9389 #endif /* CONFIG_CFS_BANDWIDTH */
9390 #endif /* CONFIG_FAIR_GROUP_SCHED */
9392 #ifdef CONFIG_RT_GROUP_SCHED
9393 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
9396 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
9399 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9401 return sched_group_rt_runtime(cgroup_tg(cgrp
));
9404 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
9407 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
9410 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
9412 return sched_group_rt_period(cgroup_tg(cgrp
));
9414 #endif /* CONFIG_RT_GROUP_SCHED */
9416 static struct cftype cpu_files
[] = {
9417 #ifdef CONFIG_FAIR_GROUP_SCHED
9420 .read_u64
= cpu_shares_read_u64
,
9421 .write_u64
= cpu_shares_write_u64
,
9424 #ifdef CONFIG_CFS_BANDWIDTH
9426 .name
= "cfs_quota_us",
9427 .read_s64
= cpu_cfs_quota_read_s64
,
9428 .write_s64
= cpu_cfs_quota_write_s64
,
9431 .name
= "cfs_period_us",
9432 .read_u64
= cpu_cfs_period_read_u64
,
9433 .write_u64
= cpu_cfs_period_write_u64
,
9437 .read_map
= cpu_stats_show
,
9440 #ifdef CONFIG_RT_GROUP_SCHED
9442 .name
= "rt_runtime_us",
9443 .read_s64
= cpu_rt_runtime_read
,
9444 .write_s64
= cpu_rt_runtime_write
,
9447 .name
= "rt_period_us",
9448 .read_u64
= cpu_rt_period_read_uint
,
9449 .write_u64
= cpu_rt_period_write_uint
,
9454 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
9456 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
9459 struct cgroup_subsys cpu_cgroup_subsys
= {
9461 .create
= cpu_cgroup_create
,
9462 .destroy
= cpu_cgroup_destroy
,
9463 .can_attach_task
= cpu_cgroup_can_attach_task
,
9464 .attach_task
= cpu_cgroup_attach_task
,
9465 .exit
= cpu_cgroup_exit
,
9466 .populate
= cpu_cgroup_populate
,
9467 .subsys_id
= cpu_cgroup_subsys_id
,
9471 #endif /* CONFIG_CGROUP_SCHED */
9473 #ifdef CONFIG_CGROUP_CPUACCT
9476 * CPU accounting code for task groups.
9478 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9479 * (balbir@in.ibm.com).
9482 /* track cpu usage of a group of tasks and its child groups */
9484 struct cgroup_subsys_state css
;
9485 /* cpuusage holds pointer to a u64-type object on every cpu */
9486 u64 __percpu
*cpuusage
;
9487 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
9488 struct cpuacct
*parent
;
9491 struct cgroup_subsys cpuacct_subsys
;
9493 /* return cpu accounting group corresponding to this container */
9494 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
9496 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
9497 struct cpuacct
, css
);
9500 /* return cpu accounting group to which this task belongs */
9501 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
9503 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
9504 struct cpuacct
, css
);
9507 /* create a new cpu accounting group */
9508 static struct cgroup_subsys_state
*cpuacct_create(
9509 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9511 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
9517 ca
->cpuusage
= alloc_percpu(u64
);
9521 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
9522 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
9523 goto out_free_counters
;
9526 ca
->parent
= cgroup_ca(cgrp
->parent
);
9532 percpu_counter_destroy(&ca
->cpustat
[i
]);
9533 free_percpu(ca
->cpuusage
);
9537 return ERR_PTR(-ENOMEM
);
9540 /* destroy an existing cpu accounting group */
9542 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9544 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9547 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
9548 percpu_counter_destroy(&ca
->cpustat
[i
]);
9549 free_percpu(ca
->cpuusage
);
9553 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
9555 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9558 #ifndef CONFIG_64BIT
9560 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
9562 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
9564 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9572 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
9574 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9576 #ifndef CONFIG_64BIT
9578 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
9580 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
9582 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9588 /* return total cpu usage (in nanoseconds) of a group */
9589 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9591 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9592 u64 totalcpuusage
= 0;
9595 for_each_present_cpu(i
)
9596 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
9598 return totalcpuusage
;
9601 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
9604 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9613 for_each_present_cpu(i
)
9614 cpuacct_cpuusage_write(ca
, i
, 0);
9620 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
9623 struct cpuacct
*ca
= cgroup_ca(cgroup
);
9627 for_each_present_cpu(i
) {
9628 percpu
= cpuacct_cpuusage_read(ca
, i
);
9629 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
9631 seq_printf(m
, "\n");
9635 static const char *cpuacct_stat_desc
[] = {
9636 [CPUACCT_STAT_USER
] = "user",
9637 [CPUACCT_STAT_SYSTEM
] = "system",
9640 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
9641 struct cgroup_map_cb
*cb
)
9643 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9646 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
9647 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
9648 val
= cputime64_to_clock_t(val
);
9649 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
9654 static struct cftype files
[] = {
9657 .read_u64
= cpuusage_read
,
9658 .write_u64
= cpuusage_write
,
9661 .name
= "usage_percpu",
9662 .read_seq_string
= cpuacct_percpu_seq_read
,
9666 .read_map
= cpuacct_stats_show
,
9670 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9672 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
9676 * charge this task's execution time to its accounting group.
9678 * called with rq->lock held.
9680 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
9685 if (unlikely(!cpuacct_subsys
.active
))
9688 cpu
= task_cpu(tsk
);
9694 for (; ca
; ca
= ca
->parent
) {
9695 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
9696 *cpuusage
+= cputime
;
9703 * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large
9704 * in cputime_t units. As a result, cpuacct_update_stats calls
9705 * percpu_counter_add with values large enough to always overflow the
9706 * per cpu batch limit causing bad SMP scalability.
9708 * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we
9709 * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled
9710 * and enabled. We cap it at INT_MAX which is the largest allowed batch value.
9713 #define CPUACCT_BATCH \
9714 min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX)
9716 #define CPUACCT_BATCH 0
9720 * Charge the system/user time to the task's accounting group.
9722 static void cpuacct_update_stats(struct task_struct
*tsk
,
9723 enum cpuacct_stat_index idx
, cputime_t val
)
9726 int batch
= CPUACCT_BATCH
;
9728 if (unlikely(!cpuacct_subsys
.active
))
9735 __percpu_counter_add(&ca
->cpustat
[idx
], val
, batch
);
9741 struct cgroup_subsys cpuacct_subsys
= {
9743 .create
= cpuacct_create
,
9744 .destroy
= cpuacct_destroy
,
9745 .populate
= cpuacct_populate
,
9746 .subsys_id
= cpuacct_subsys_id
,
9748 #endif /* CONFIG_CGROUP_CPUACCT */