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 <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.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/kthread.h>
58 #include <linux/seq_file.h>
59 #include <linux/sysctl.h>
60 #include <linux/syscalls.h>
61 #include <linux/times.h>
62 #include <linux/tsacct_kern.h>
63 #include <linux/kprobes.h>
64 #include <linux/delayacct.h>
65 #include <linux/reciprocal_div.h>
66 #include <linux/unistd.h>
67 #include <linux/pagemap.h>
68 #include <linux/hrtimer.h>
69 #include <linux/tick.h>
72 #include <asm/irq_regs.h>
75 * Scheduler clock - returns current time in nanosec units.
76 * This is default implementation.
77 * Architectures and sub-architectures can override this.
79 unsigned long long __attribute__((weak
)) sched_clock(void)
81 return (unsigned long long)jiffies
* (NSEC_PER_SEC
/ HZ
);
85 * Convert user-nice values [ -20 ... 0 ... 19 ]
86 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
89 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
90 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
91 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
94 * 'User priority' is the nice value converted to something we
95 * can work with better when scaling various scheduler parameters,
96 * it's a [ 0 ... 39 ] range.
98 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
99 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
100 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
103 * Helpers for converting nanosecond timing to jiffy resolution
105 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
107 #define NICE_0_LOAD SCHED_LOAD_SCALE
108 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
111 * These are the 'tuning knobs' of the scheduler:
113 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
114 * Timeslices get refilled after they expire.
116 #define DEF_TIMESLICE (100 * HZ / 1000)
119 * single value that denotes runtime == period, ie unlimited time.
121 #define RUNTIME_INF ((u64)~0ULL)
125 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
126 * Since cpu_power is a 'constant', we can use a reciprocal divide.
128 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
130 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
134 * Each time a sched group cpu_power is changed,
135 * we must compute its reciprocal value
137 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
139 sg
->__cpu_power
+= val
;
140 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
144 static inline int rt_policy(int policy
)
146 if (unlikely(policy
== SCHED_FIFO
) || unlikely(policy
== SCHED_RR
))
151 static inline int task_has_rt_policy(struct task_struct
*p
)
153 return rt_policy(p
->policy
);
157 * This is the priority-queue data structure of the RT scheduling class:
159 struct rt_prio_array
{
160 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
161 struct list_head queue
[MAX_RT_PRIO
];
164 struct rt_bandwidth
{
167 struct hrtimer rt_period_timer
;
170 static struct rt_bandwidth def_rt_bandwidth
;
172 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
174 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
176 struct rt_bandwidth
*rt_b
=
177 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
183 now
= hrtimer_cb_get_time(timer
);
184 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
189 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
192 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
196 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
198 rt_b
->rt_period
= ns_to_ktime(period
);
199 rt_b
->rt_runtime
= runtime
;
201 hrtimer_init(&rt_b
->rt_period_timer
,
202 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
203 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
204 rt_b
->rt_period_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
207 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
211 if (rt_b
->rt_runtime
== RUNTIME_INF
)
214 if (hrtimer_active(&rt_b
->rt_period_timer
))
217 spin_lock(&rt_b
->rt_runtime_lock
);
219 if (hrtimer_active(&rt_b
->rt_period_timer
))
222 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
223 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
224 hrtimer_start(&rt_b
->rt_period_timer
,
225 rt_b
->rt_period_timer
.expires
,
228 spin_unlock(&rt_b
->rt_runtime_lock
);
231 #ifdef CONFIG_RT_GROUP_SCHED
232 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
234 hrtimer_cancel(&rt_b
->rt_period_timer
);
238 #ifdef CONFIG_GROUP_SCHED
240 #include <linux/cgroup.h>
244 static LIST_HEAD(task_groups
);
246 /* task group related information */
248 #ifdef CONFIG_CGROUP_SCHED
249 struct cgroup_subsys_state css
;
252 #ifdef CONFIG_FAIR_GROUP_SCHED
253 /* schedulable entities of this group on each cpu */
254 struct sched_entity
**se
;
255 /* runqueue "owned" by this group on each cpu */
256 struct cfs_rq
**cfs_rq
;
257 unsigned long shares
;
260 #ifdef CONFIG_RT_GROUP_SCHED
261 struct sched_rt_entity
**rt_se
;
262 struct rt_rq
**rt_rq
;
264 struct rt_bandwidth rt_bandwidth
;
268 struct list_head list
;
271 #ifdef CONFIG_FAIR_GROUP_SCHED
272 /* Default task group's sched entity on each cpu */
273 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
274 /* Default task group's cfs_rq on each cpu */
275 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
277 static struct sched_entity
*init_sched_entity_p
[NR_CPUS
];
278 static struct cfs_rq
*init_cfs_rq_p
[NR_CPUS
];
281 #ifdef CONFIG_RT_GROUP_SCHED
282 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
283 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
285 static struct sched_rt_entity
*init_sched_rt_entity_p
[NR_CPUS
];
286 static struct rt_rq
*init_rt_rq_p
[NR_CPUS
];
289 /* task_group_lock serializes add/remove of task groups and also changes to
290 * a task group's cpu shares.
292 static DEFINE_SPINLOCK(task_group_lock
);
294 /* doms_cur_mutex serializes access to doms_cur[] array */
295 static DEFINE_MUTEX(doms_cur_mutex
);
297 #ifdef CONFIG_FAIR_GROUP_SCHED
298 #ifdef CONFIG_USER_SCHED
299 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
301 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
304 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
307 /* Default task group.
308 * Every task in system belong to this group at bootup.
310 struct task_group init_task_group
= {
311 #ifdef CONFIG_FAIR_GROUP_SCHED
312 .se
= init_sched_entity_p
,
313 .cfs_rq
= init_cfs_rq_p
,
316 #ifdef CONFIG_RT_GROUP_SCHED
317 .rt_se
= init_sched_rt_entity_p
,
318 .rt_rq
= init_rt_rq_p
,
322 /* return group to which a task belongs */
323 static inline struct task_group
*task_group(struct task_struct
*p
)
325 struct task_group
*tg
;
327 #ifdef CONFIG_USER_SCHED
329 #elif defined(CONFIG_CGROUP_SCHED)
330 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
331 struct task_group
, css
);
333 tg
= &init_task_group
;
338 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
339 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
341 #ifdef CONFIG_FAIR_GROUP_SCHED
342 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
343 p
->se
.parent
= task_group(p
)->se
[cpu
];
346 #ifdef CONFIG_RT_GROUP_SCHED
347 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
348 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
352 static inline void lock_doms_cur(void)
354 mutex_lock(&doms_cur_mutex
);
357 static inline void unlock_doms_cur(void)
359 mutex_unlock(&doms_cur_mutex
);
364 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
365 static inline void lock_doms_cur(void) { }
366 static inline void unlock_doms_cur(void) { }
368 #endif /* CONFIG_GROUP_SCHED */
370 /* CFS-related fields in a runqueue */
372 struct load_weight load
;
373 unsigned long nr_running
;
378 struct rb_root tasks_timeline
;
379 struct rb_node
*rb_leftmost
;
380 struct rb_node
*rb_load_balance_curr
;
381 /* 'curr' points to currently running entity on this cfs_rq.
382 * It is set to NULL otherwise (i.e when none are currently running).
384 struct sched_entity
*curr
, *next
;
386 unsigned long nr_spread_over
;
388 #ifdef CONFIG_FAIR_GROUP_SCHED
389 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
392 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
393 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
394 * (like users, containers etc.)
396 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
397 * list is used during load balance.
399 struct list_head leaf_cfs_rq_list
;
400 struct task_group
*tg
; /* group that "owns" this runqueue */
404 /* Real-Time classes' related field in a runqueue: */
406 struct rt_prio_array active
;
407 unsigned long rt_nr_running
;
408 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
409 int highest_prio
; /* highest queued rt task prio */
412 unsigned long rt_nr_migratory
;
418 #ifdef CONFIG_RT_GROUP_SCHED
419 unsigned long rt_nr_boosted
;
422 struct list_head leaf_rt_rq_list
;
423 struct task_group
*tg
;
424 struct sched_rt_entity
*rt_se
;
431 * We add the notion of a root-domain which will be used to define per-domain
432 * variables. Each exclusive cpuset essentially defines an island domain by
433 * fully partitioning the member cpus from any other cpuset. Whenever a new
434 * exclusive cpuset is created, we also create and attach a new root-domain
444 * The "RT overload" flag: it gets set if a CPU has more than
445 * one runnable RT task.
452 * By default the system creates a single root-domain with all cpus as
453 * members (mimicking the global state we have today).
455 static struct root_domain def_root_domain
;
460 * This is the main, per-CPU runqueue data structure.
462 * Locking rule: those places that want to lock multiple runqueues
463 * (such as the load balancing or the thread migration code), lock
464 * acquire operations must be ordered by ascending &runqueue.
471 * nr_running and cpu_load should be in the same cacheline because
472 * remote CPUs use both these fields when doing load calculation.
474 unsigned long nr_running
;
475 #define CPU_LOAD_IDX_MAX 5
476 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
477 unsigned char idle_at_tick
;
479 unsigned long last_tick_seen
;
480 unsigned char in_nohz_recently
;
482 /* capture load from *all* tasks on this cpu: */
483 struct load_weight load
;
484 unsigned long nr_load_updates
;
490 #ifdef CONFIG_FAIR_GROUP_SCHED
491 /* list of leaf cfs_rq on this cpu: */
492 struct list_head leaf_cfs_rq_list
;
494 #ifdef CONFIG_RT_GROUP_SCHED
495 struct list_head leaf_rt_rq_list
;
499 * This is part of a global counter where only the total sum
500 * over all CPUs matters. A task can increase this counter on
501 * one CPU and if it got migrated afterwards it may decrease
502 * it on another CPU. Always updated under the runqueue lock:
504 unsigned long nr_uninterruptible
;
506 struct task_struct
*curr
, *idle
;
507 unsigned long next_balance
;
508 struct mm_struct
*prev_mm
;
510 u64 clock
, prev_clock_raw
;
513 unsigned int clock_warps
, clock_overflows
, clock_underflows
;
515 unsigned int clock_deep_idle_events
;
521 struct root_domain
*rd
;
522 struct sched_domain
*sd
;
524 /* For active balancing */
527 /* cpu of this runqueue: */
530 struct task_struct
*migration_thread
;
531 struct list_head migration_queue
;
534 #ifdef CONFIG_SCHED_HRTICK
535 unsigned long hrtick_flags
;
536 ktime_t hrtick_expire
;
537 struct hrtimer hrtick_timer
;
540 #ifdef CONFIG_SCHEDSTATS
542 struct sched_info rq_sched_info
;
544 /* sys_sched_yield() stats */
545 unsigned int yld_exp_empty
;
546 unsigned int yld_act_empty
;
547 unsigned int yld_both_empty
;
548 unsigned int yld_count
;
550 /* schedule() stats */
551 unsigned int sched_switch
;
552 unsigned int sched_count
;
553 unsigned int sched_goidle
;
555 /* try_to_wake_up() stats */
556 unsigned int ttwu_count
;
557 unsigned int ttwu_local
;
560 unsigned int bkl_count
;
562 struct lock_class_key rq_lock_key
;
565 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
567 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
)
569 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
);
572 static inline int cpu_of(struct rq
*rq
)
582 static inline bool nohz_on(int cpu
)
584 return tick_get_tick_sched(cpu
)->nohz_mode
!= NOHZ_MODE_INACTIVE
;
587 static inline u64
max_skipped_ticks(struct rq
*rq
)
589 return nohz_on(cpu_of(rq
)) ? jiffies
- rq
->last_tick_seen
+ 2 : 1;
592 static inline void update_last_tick_seen(struct rq
*rq
)
594 rq
->last_tick_seen
= jiffies
;
597 static inline u64
max_skipped_ticks(struct rq
*rq
)
602 static inline void update_last_tick_seen(struct rq
*rq
)
608 * Update the per-runqueue clock, as finegrained as the platform can give
609 * us, but without assuming monotonicity, etc.:
611 static void __update_rq_clock(struct rq
*rq
)
613 u64 prev_raw
= rq
->prev_clock_raw
;
614 u64 now
= sched_clock();
615 s64 delta
= now
- prev_raw
;
616 u64 clock
= rq
->clock
;
618 #ifdef CONFIG_SCHED_DEBUG
619 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
622 * Protect against sched_clock() occasionally going backwards:
624 if (unlikely(delta
< 0)) {
629 * Catch too large forward jumps too:
631 u64 max_jump
= max_skipped_ticks(rq
) * TICK_NSEC
;
632 u64 max_time
= rq
->tick_timestamp
+ max_jump
;
634 if (unlikely(clock
+ delta
> max_time
)) {
635 if (clock
< max_time
)
639 rq
->clock_overflows
++;
641 if (unlikely(delta
> rq
->clock_max_delta
))
642 rq
->clock_max_delta
= delta
;
647 rq
->prev_clock_raw
= now
;
651 static void update_rq_clock(struct rq
*rq
)
653 if (likely(smp_processor_id() == cpu_of(rq
)))
654 __update_rq_clock(rq
);
658 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
659 * See detach_destroy_domains: synchronize_sched for details.
661 * The domain tree of any CPU may only be accessed from within
662 * preempt-disabled sections.
664 #define for_each_domain(cpu, __sd) \
665 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
667 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
668 #define this_rq() (&__get_cpu_var(runqueues))
669 #define task_rq(p) cpu_rq(task_cpu(p))
670 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
673 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
675 #ifdef CONFIG_SCHED_DEBUG
676 # define const_debug __read_mostly
678 # define const_debug static const
682 * Debugging: various feature bits
685 SCHED_FEAT_NEW_FAIR_SLEEPERS
= 1,
686 SCHED_FEAT_WAKEUP_PREEMPT
= 2,
687 SCHED_FEAT_START_DEBIT
= 4,
688 SCHED_FEAT_AFFINE_WAKEUPS
= 8,
689 SCHED_FEAT_CACHE_HOT_BUDDY
= 16,
690 SCHED_FEAT_SYNC_WAKEUPS
= 32,
691 SCHED_FEAT_HRTICK
= 64,
692 SCHED_FEAT_DOUBLE_TICK
= 128,
695 const_debug
unsigned int sysctl_sched_features
=
696 SCHED_FEAT_NEW_FAIR_SLEEPERS
* 1 |
697 SCHED_FEAT_WAKEUP_PREEMPT
* 1 |
698 SCHED_FEAT_START_DEBIT
* 1 |
699 SCHED_FEAT_AFFINE_WAKEUPS
* 1 |
700 SCHED_FEAT_CACHE_HOT_BUDDY
* 1 |
701 SCHED_FEAT_SYNC_WAKEUPS
* 1 |
702 SCHED_FEAT_HRTICK
* 1 |
703 SCHED_FEAT_DOUBLE_TICK
* 0;
705 #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
708 * Number of tasks to iterate in a single balance run.
709 * Limited because this is done with IRQs disabled.
711 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
714 * period over which we measure -rt task cpu usage in us.
717 unsigned int sysctl_sched_rt_period
= 1000000;
719 static __read_mostly
int scheduler_running
;
722 * part of the period that we allow rt tasks to run in us.
725 int sysctl_sched_rt_runtime
= 950000;
727 static inline u64
global_rt_period(void)
729 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
732 static inline u64
global_rt_runtime(void)
734 if (sysctl_sched_rt_period
< 0)
737 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
740 static const unsigned long long time_sync_thresh
= 100000;
742 static DEFINE_PER_CPU(unsigned long long, time_offset
);
743 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time
);
746 * Global lock which we take every now and then to synchronize
747 * the CPUs time. This method is not warp-safe, but it's good
748 * enough to synchronize slowly diverging time sources and thus
749 * it's good enough for tracing:
751 static DEFINE_SPINLOCK(time_sync_lock
);
752 static unsigned long long prev_global_time
;
754 static unsigned long long __sync_cpu_clock(cycles_t time
, int cpu
)
758 spin_lock_irqsave(&time_sync_lock
, flags
);
760 if (time
< prev_global_time
) {
761 per_cpu(time_offset
, cpu
) += prev_global_time
- time
;
762 time
= prev_global_time
;
764 prev_global_time
= time
;
767 spin_unlock_irqrestore(&time_sync_lock
, flags
);
772 static unsigned long long __cpu_clock(int cpu
)
774 unsigned long long now
;
779 * Only call sched_clock() if the scheduler has already been
780 * initialized (some code might call cpu_clock() very early):
782 if (unlikely(!scheduler_running
))
785 local_irq_save(flags
);
789 local_irq_restore(flags
);
795 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
796 * clock constructed from sched_clock():
798 unsigned long long cpu_clock(int cpu
)
800 unsigned long long prev_cpu_time
, time
, delta_time
;
802 prev_cpu_time
= per_cpu(prev_cpu_time
, cpu
);
803 time
= __cpu_clock(cpu
) + per_cpu(time_offset
, cpu
);
804 delta_time
= time
-prev_cpu_time
;
806 if (unlikely(delta_time
> time_sync_thresh
))
807 time
= __sync_cpu_clock(time
, cpu
);
811 EXPORT_SYMBOL_GPL(cpu_clock
);
813 #ifndef prepare_arch_switch
814 # define prepare_arch_switch(next) do { } while (0)
816 #ifndef finish_arch_switch
817 # define finish_arch_switch(prev) do { } while (0)
820 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
822 return rq
->curr
== p
;
825 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
826 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
828 return task_current(rq
, p
);
831 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
835 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
837 #ifdef CONFIG_DEBUG_SPINLOCK
838 /* this is a valid case when another task releases the spinlock */
839 rq
->lock
.owner
= current
;
842 * If we are tracking spinlock dependencies then we have to
843 * fix up the runqueue lock - which gets 'carried over' from
846 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
848 spin_unlock_irq(&rq
->lock
);
851 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
852 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
857 return task_current(rq
, p
);
861 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
865 * We can optimise this out completely for !SMP, because the
866 * SMP rebalancing from interrupt is the only thing that cares
871 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
872 spin_unlock_irq(&rq
->lock
);
874 spin_unlock(&rq
->lock
);
878 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
882 * After ->oncpu is cleared, the task can be moved to a different CPU.
883 * We must ensure this doesn't happen until the switch is completely
889 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
893 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
896 * __task_rq_lock - lock the runqueue a given task resides on.
897 * Must be called interrupts disabled.
899 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
903 struct rq
*rq
= task_rq(p
);
904 spin_lock(&rq
->lock
);
905 if (likely(rq
== task_rq(p
)))
907 spin_unlock(&rq
->lock
);
912 * task_rq_lock - lock the runqueue a given task resides on and disable
913 * interrupts. Note the ordering: we can safely lookup the task_rq without
914 * explicitly disabling preemption.
916 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
922 local_irq_save(*flags
);
924 spin_lock(&rq
->lock
);
925 if (likely(rq
== task_rq(p
)))
927 spin_unlock_irqrestore(&rq
->lock
, *flags
);
931 static void __task_rq_unlock(struct rq
*rq
)
934 spin_unlock(&rq
->lock
);
937 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
940 spin_unlock_irqrestore(&rq
->lock
, *flags
);
944 * this_rq_lock - lock this runqueue and disable interrupts.
946 static struct rq
*this_rq_lock(void)
953 spin_lock(&rq
->lock
);
959 * We are going deep-idle (irqs are disabled):
961 void sched_clock_idle_sleep_event(void)
963 struct rq
*rq
= cpu_rq(smp_processor_id());
965 spin_lock(&rq
->lock
);
966 __update_rq_clock(rq
);
967 spin_unlock(&rq
->lock
);
968 rq
->clock_deep_idle_events
++;
970 EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event
);
973 * We just idled delta nanoseconds (called with irqs disabled):
975 void sched_clock_idle_wakeup_event(u64 delta_ns
)
977 struct rq
*rq
= cpu_rq(smp_processor_id());
978 u64 now
= sched_clock();
980 rq
->idle_clock
+= delta_ns
;
982 * Override the previous timestamp and ignore all
983 * sched_clock() deltas that occured while we idled,
984 * and use the PM-provided delta_ns to advance the
987 spin_lock(&rq
->lock
);
988 rq
->prev_clock_raw
= now
;
989 rq
->clock
+= delta_ns
;
990 spin_unlock(&rq
->lock
);
991 touch_softlockup_watchdog();
993 EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event
);
995 static void __resched_task(struct task_struct
*p
, int tif_bit
);
997 static inline void resched_task(struct task_struct
*p
)
999 __resched_task(p
, TIF_NEED_RESCHED
);
1002 #ifdef CONFIG_SCHED_HRTICK
1004 * Use HR-timers to deliver accurate preemption points.
1006 * Its all a bit involved since we cannot program an hrt while holding the
1007 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1010 * When we get rescheduled we reprogram the hrtick_timer outside of the
1013 static inline void resched_hrt(struct task_struct
*p
)
1015 __resched_task(p
, TIF_HRTICK_RESCHED
);
1018 static inline void resched_rq(struct rq
*rq
)
1020 unsigned long flags
;
1022 spin_lock_irqsave(&rq
->lock
, flags
);
1023 resched_task(rq
->curr
);
1024 spin_unlock_irqrestore(&rq
->lock
, flags
);
1028 HRTICK_SET
, /* re-programm hrtick_timer */
1029 HRTICK_RESET
, /* not a new slice */
1034 * - enabled by features
1035 * - hrtimer is actually high res
1037 static inline int hrtick_enabled(struct rq
*rq
)
1039 if (!sched_feat(HRTICK
))
1041 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1045 * Called to set the hrtick timer state.
1047 * called with rq->lock held and irqs disabled
1049 static void hrtick_start(struct rq
*rq
, u64 delay
, int reset
)
1051 assert_spin_locked(&rq
->lock
);
1054 * preempt at: now + delay
1057 ktime_add_ns(rq
->hrtick_timer
.base
->get_time(), delay
);
1059 * indicate we need to program the timer
1061 __set_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1063 __set_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1066 * New slices are called from the schedule path and don't need a
1067 * forced reschedule.
1070 resched_hrt(rq
->curr
);
1073 static void hrtick_clear(struct rq
*rq
)
1075 if (hrtimer_active(&rq
->hrtick_timer
))
1076 hrtimer_cancel(&rq
->hrtick_timer
);
1080 * Update the timer from the possible pending state.
1082 static void hrtick_set(struct rq
*rq
)
1086 unsigned long flags
;
1088 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1090 spin_lock_irqsave(&rq
->lock
, flags
);
1091 set
= __test_and_clear_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1092 reset
= __test_and_clear_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1093 time
= rq
->hrtick_expire
;
1094 clear_thread_flag(TIF_HRTICK_RESCHED
);
1095 spin_unlock_irqrestore(&rq
->lock
, flags
);
1098 hrtimer_start(&rq
->hrtick_timer
, time
, HRTIMER_MODE_ABS
);
1099 if (reset
&& !hrtimer_active(&rq
->hrtick_timer
))
1106 * High-resolution timer tick.
1107 * Runs from hardirq context with interrupts disabled.
1109 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1111 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1113 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1115 spin_lock(&rq
->lock
);
1116 __update_rq_clock(rq
);
1117 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1118 spin_unlock(&rq
->lock
);
1120 return HRTIMER_NORESTART
;
1123 static inline void init_rq_hrtick(struct rq
*rq
)
1125 rq
->hrtick_flags
= 0;
1126 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1127 rq
->hrtick_timer
.function
= hrtick
;
1128 rq
->hrtick_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1131 void hrtick_resched(void)
1134 unsigned long flags
;
1136 if (!test_thread_flag(TIF_HRTICK_RESCHED
))
1139 local_irq_save(flags
);
1140 rq
= cpu_rq(smp_processor_id());
1142 local_irq_restore(flags
);
1145 static inline void hrtick_clear(struct rq
*rq
)
1149 static inline void hrtick_set(struct rq
*rq
)
1153 static inline void init_rq_hrtick(struct rq
*rq
)
1157 void hrtick_resched(void)
1163 * resched_task - mark a task 'to be rescheduled now'.
1165 * On UP this means the setting of the need_resched flag, on SMP it
1166 * might also involve a cross-CPU call to trigger the scheduler on
1171 #ifndef tsk_is_polling
1172 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1175 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1179 assert_spin_locked(&task_rq(p
)->lock
);
1181 if (unlikely(test_tsk_thread_flag(p
, tif_bit
)))
1184 set_tsk_thread_flag(p
, tif_bit
);
1187 if (cpu
== smp_processor_id())
1190 /* NEED_RESCHED must be visible before we test polling */
1192 if (!tsk_is_polling(p
))
1193 smp_send_reschedule(cpu
);
1196 static void resched_cpu(int cpu
)
1198 struct rq
*rq
= cpu_rq(cpu
);
1199 unsigned long flags
;
1201 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1203 resched_task(cpu_curr(cpu
));
1204 spin_unlock_irqrestore(&rq
->lock
, flags
);
1209 * When add_timer_on() enqueues a timer into the timer wheel of an
1210 * idle CPU then this timer might expire before the next timer event
1211 * which is scheduled to wake up that CPU. In case of a completely
1212 * idle system the next event might even be infinite time into the
1213 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1214 * leaves the inner idle loop so the newly added timer is taken into
1215 * account when the CPU goes back to idle and evaluates the timer
1216 * wheel for the next timer event.
1218 void wake_up_idle_cpu(int cpu
)
1220 struct rq
*rq
= cpu_rq(cpu
);
1222 if (cpu
== smp_processor_id())
1226 * This is safe, as this function is called with the timer
1227 * wheel base lock of (cpu) held. When the CPU is on the way
1228 * to idle and has not yet set rq->curr to idle then it will
1229 * be serialized on the timer wheel base lock and take the new
1230 * timer into account automatically.
1232 if (rq
->curr
!= rq
->idle
)
1236 * We can set TIF_RESCHED on the idle task of the other CPU
1237 * lockless. The worst case is that the other CPU runs the
1238 * idle task through an additional NOOP schedule()
1240 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1242 /* NEED_RESCHED must be visible before we test polling */
1244 if (!tsk_is_polling(rq
->idle
))
1245 smp_send_reschedule(cpu
);
1250 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1252 assert_spin_locked(&task_rq(p
)->lock
);
1253 set_tsk_thread_flag(p
, tif_bit
);
1257 #if BITS_PER_LONG == 32
1258 # define WMULT_CONST (~0UL)
1260 # define WMULT_CONST (1UL << 32)
1263 #define WMULT_SHIFT 32
1266 * Shift right and round:
1268 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1270 static unsigned long
1271 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1272 struct load_weight
*lw
)
1276 if (unlikely(!lw
->inv_weight
))
1277 lw
->inv_weight
= (WMULT_CONST
-lw
->weight
/2) / (lw
->weight
+1);
1279 tmp
= (u64
)delta_exec
* weight
;
1281 * Check whether we'd overflow the 64-bit multiplication:
1283 if (unlikely(tmp
> WMULT_CONST
))
1284 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1287 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1289 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1292 static inline unsigned long
1293 calc_delta_fair(unsigned long delta_exec
, struct load_weight
*lw
)
1295 return calc_delta_mine(delta_exec
, NICE_0_LOAD
, lw
);
1298 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1304 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1311 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1312 * of tasks with abnormal "nice" values across CPUs the contribution that
1313 * each task makes to its run queue's load is weighted according to its
1314 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1315 * scaled version of the new time slice allocation that they receive on time
1319 #define WEIGHT_IDLEPRIO 2
1320 #define WMULT_IDLEPRIO (1 << 31)
1323 * Nice levels are multiplicative, with a gentle 10% change for every
1324 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1325 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1326 * that remained on nice 0.
1328 * The "10% effect" is relative and cumulative: from _any_ nice level,
1329 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1330 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1331 * If a task goes up by ~10% and another task goes down by ~10% then
1332 * the relative distance between them is ~25%.)
1334 static const int prio_to_weight
[40] = {
1335 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1336 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1337 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1338 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1339 /* 0 */ 1024, 820, 655, 526, 423,
1340 /* 5 */ 335, 272, 215, 172, 137,
1341 /* 10 */ 110, 87, 70, 56, 45,
1342 /* 15 */ 36, 29, 23, 18, 15,
1346 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1348 * In cases where the weight does not change often, we can use the
1349 * precalculated inverse to speed up arithmetics by turning divisions
1350 * into multiplications:
1352 static const u32 prio_to_wmult
[40] = {
1353 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1354 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1355 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1356 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1357 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1358 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1359 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1360 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1363 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1366 * runqueue iterator, to support SMP load-balancing between different
1367 * scheduling classes, without having to expose their internal data
1368 * structures to the load-balancing proper:
1370 struct rq_iterator
{
1372 struct task_struct
*(*start
)(void *);
1373 struct task_struct
*(*next
)(void *);
1377 static unsigned long
1378 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1379 unsigned long max_load_move
, struct sched_domain
*sd
,
1380 enum cpu_idle_type idle
, int *all_pinned
,
1381 int *this_best_prio
, struct rq_iterator
*iterator
);
1384 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1385 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1386 struct rq_iterator
*iterator
);
1389 #ifdef CONFIG_CGROUP_CPUACCT
1390 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1392 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1396 static unsigned long source_load(int cpu
, int type
);
1397 static unsigned long target_load(int cpu
, int type
);
1398 static unsigned long cpu_avg_load_per_task(int cpu
);
1399 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1400 #endif /* CONFIG_SMP */
1402 #include "sched_stats.h"
1403 #include "sched_idletask.c"
1404 #include "sched_fair.c"
1405 #include "sched_rt.c"
1406 #ifdef CONFIG_SCHED_DEBUG
1407 # include "sched_debug.c"
1410 #define sched_class_highest (&rt_sched_class)
1412 static inline void inc_load(struct rq
*rq
, const struct task_struct
*p
)
1414 update_load_add(&rq
->load
, p
->se
.load
.weight
);
1417 static inline void dec_load(struct rq
*rq
, const struct task_struct
*p
)
1419 update_load_sub(&rq
->load
, p
->se
.load
.weight
);
1422 static void inc_nr_running(struct task_struct
*p
, struct rq
*rq
)
1428 static void dec_nr_running(struct task_struct
*p
, struct rq
*rq
)
1434 static void set_load_weight(struct task_struct
*p
)
1436 if (task_has_rt_policy(p
)) {
1437 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1438 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1443 * SCHED_IDLE tasks get minimal weight:
1445 if (p
->policy
== SCHED_IDLE
) {
1446 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1447 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1451 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1452 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1455 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1457 sched_info_queued(p
);
1458 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1462 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1464 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1469 * __normal_prio - return the priority that is based on the static prio
1471 static inline int __normal_prio(struct task_struct
*p
)
1473 return p
->static_prio
;
1477 * Calculate the expected normal priority: i.e. priority
1478 * without taking RT-inheritance into account. Might be
1479 * boosted by interactivity modifiers. Changes upon fork,
1480 * setprio syscalls, and whenever the interactivity
1481 * estimator recalculates.
1483 static inline int normal_prio(struct task_struct
*p
)
1487 if (task_has_rt_policy(p
))
1488 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1490 prio
= __normal_prio(p
);
1495 * Calculate the current priority, i.e. the priority
1496 * taken into account by the scheduler. This value might
1497 * be boosted by RT tasks, or might be boosted by
1498 * interactivity modifiers. Will be RT if the task got
1499 * RT-boosted. If not then it returns p->normal_prio.
1501 static int effective_prio(struct task_struct
*p
)
1503 p
->normal_prio
= normal_prio(p
);
1505 * If we are RT tasks or we were boosted to RT priority,
1506 * keep the priority unchanged. Otherwise, update priority
1507 * to the normal priority:
1509 if (!rt_prio(p
->prio
))
1510 return p
->normal_prio
;
1515 * activate_task - move a task to the runqueue.
1517 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1519 if (task_contributes_to_load(p
))
1520 rq
->nr_uninterruptible
--;
1522 enqueue_task(rq
, p
, wakeup
);
1523 inc_nr_running(p
, rq
);
1527 * deactivate_task - remove a task from the runqueue.
1529 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1531 if (task_contributes_to_load(p
))
1532 rq
->nr_uninterruptible
++;
1534 dequeue_task(rq
, p
, sleep
);
1535 dec_nr_running(p
, rq
);
1539 * task_curr - is this task currently executing on a CPU?
1540 * @p: the task in question.
1542 inline int task_curr(const struct task_struct
*p
)
1544 return cpu_curr(task_cpu(p
)) == p
;
1547 /* Used instead of source_load when we know the type == 0 */
1548 unsigned long weighted_cpuload(const int cpu
)
1550 return cpu_rq(cpu
)->load
.weight
;
1553 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1555 set_task_rq(p
, cpu
);
1558 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1559 * successfuly executed on another CPU. We must ensure that updates of
1560 * per-task data have been completed by this moment.
1563 task_thread_info(p
)->cpu
= cpu
;
1567 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1568 const struct sched_class
*prev_class
,
1569 int oldprio
, int running
)
1571 if (prev_class
!= p
->sched_class
) {
1572 if (prev_class
->switched_from
)
1573 prev_class
->switched_from(rq
, p
, running
);
1574 p
->sched_class
->switched_to(rq
, p
, running
);
1576 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1582 * Is this task likely cache-hot:
1585 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1590 * Buddy candidates are cache hot:
1592 if (sched_feat(CACHE_HOT_BUDDY
) && (&p
->se
== cfs_rq_of(&p
->se
)->next
))
1595 if (p
->sched_class
!= &fair_sched_class
)
1598 if (sysctl_sched_migration_cost
== -1)
1600 if (sysctl_sched_migration_cost
== 0)
1603 delta
= now
- p
->se
.exec_start
;
1605 return delta
< (s64
)sysctl_sched_migration_cost
;
1609 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1611 int old_cpu
= task_cpu(p
);
1612 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1613 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1614 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1617 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1619 #ifdef CONFIG_SCHEDSTATS
1620 if (p
->se
.wait_start
)
1621 p
->se
.wait_start
-= clock_offset
;
1622 if (p
->se
.sleep_start
)
1623 p
->se
.sleep_start
-= clock_offset
;
1624 if (p
->se
.block_start
)
1625 p
->se
.block_start
-= clock_offset
;
1626 if (old_cpu
!= new_cpu
) {
1627 schedstat_inc(p
, se
.nr_migrations
);
1628 if (task_hot(p
, old_rq
->clock
, NULL
))
1629 schedstat_inc(p
, se
.nr_forced2_migrations
);
1632 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1633 new_cfsrq
->min_vruntime
;
1635 __set_task_cpu(p
, new_cpu
);
1638 struct migration_req
{
1639 struct list_head list
;
1641 struct task_struct
*task
;
1644 struct completion done
;
1648 * The task's runqueue lock must be held.
1649 * Returns true if you have to wait for migration thread.
1652 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1654 struct rq
*rq
= task_rq(p
);
1657 * If the task is not on a runqueue (and not running), then
1658 * it is sufficient to simply update the task's cpu field.
1660 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1661 set_task_cpu(p
, dest_cpu
);
1665 init_completion(&req
->done
);
1667 req
->dest_cpu
= dest_cpu
;
1668 list_add(&req
->list
, &rq
->migration_queue
);
1674 * wait_task_inactive - wait for a thread to unschedule.
1676 * The caller must ensure that the task *will* unschedule sometime soon,
1677 * else this function might spin for a *long* time. This function can't
1678 * be called with interrupts off, or it may introduce deadlock with
1679 * smp_call_function() if an IPI is sent by the same process we are
1680 * waiting to become inactive.
1682 void wait_task_inactive(struct task_struct
*p
)
1684 unsigned long flags
;
1690 * We do the initial early heuristics without holding
1691 * any task-queue locks at all. We'll only try to get
1692 * the runqueue lock when things look like they will
1698 * If the task is actively running on another CPU
1699 * still, just relax and busy-wait without holding
1702 * NOTE! Since we don't hold any locks, it's not
1703 * even sure that "rq" stays as the right runqueue!
1704 * But we don't care, since "task_running()" will
1705 * return false if the runqueue has changed and p
1706 * is actually now running somewhere else!
1708 while (task_running(rq
, p
))
1712 * Ok, time to look more closely! We need the rq
1713 * lock now, to be *sure*. If we're wrong, we'll
1714 * just go back and repeat.
1716 rq
= task_rq_lock(p
, &flags
);
1717 running
= task_running(rq
, p
);
1718 on_rq
= p
->se
.on_rq
;
1719 task_rq_unlock(rq
, &flags
);
1722 * Was it really running after all now that we
1723 * checked with the proper locks actually held?
1725 * Oops. Go back and try again..
1727 if (unlikely(running
)) {
1733 * It's not enough that it's not actively running,
1734 * it must be off the runqueue _entirely_, and not
1737 * So if it wa still runnable (but just not actively
1738 * running right now), it's preempted, and we should
1739 * yield - it could be a while.
1741 if (unlikely(on_rq
)) {
1742 schedule_timeout_uninterruptible(1);
1747 * Ahh, all good. It wasn't running, and it wasn't
1748 * runnable, which means that it will never become
1749 * running in the future either. We're all done!
1756 * kick_process - kick a running thread to enter/exit the kernel
1757 * @p: the to-be-kicked thread
1759 * Cause a process which is running on another CPU to enter
1760 * kernel-mode, without any delay. (to get signals handled.)
1762 * NOTE: this function doesnt have to take the runqueue lock,
1763 * because all it wants to ensure is that the remote task enters
1764 * the kernel. If the IPI races and the task has been migrated
1765 * to another CPU then no harm is done and the purpose has been
1768 void kick_process(struct task_struct
*p
)
1774 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1775 smp_send_reschedule(cpu
);
1780 * Return a low guess at the load of a migration-source cpu weighted
1781 * according to the scheduling class and "nice" value.
1783 * We want to under-estimate the load of migration sources, to
1784 * balance conservatively.
1786 static unsigned long source_load(int cpu
, int type
)
1788 struct rq
*rq
= cpu_rq(cpu
);
1789 unsigned long total
= weighted_cpuload(cpu
);
1794 return min(rq
->cpu_load
[type
-1], total
);
1798 * Return a high guess at the load of a migration-target cpu weighted
1799 * according to the scheduling class and "nice" value.
1801 static unsigned long target_load(int cpu
, int type
)
1803 struct rq
*rq
= cpu_rq(cpu
);
1804 unsigned long total
= weighted_cpuload(cpu
);
1809 return max(rq
->cpu_load
[type
-1], total
);
1813 * Return the average load per task on the cpu's run queue
1815 static unsigned long cpu_avg_load_per_task(int cpu
)
1817 struct rq
*rq
= cpu_rq(cpu
);
1818 unsigned long total
= weighted_cpuload(cpu
);
1819 unsigned long n
= rq
->nr_running
;
1821 return n
? total
/ n
: SCHED_LOAD_SCALE
;
1825 * find_idlest_group finds and returns the least busy CPU group within the
1828 static struct sched_group
*
1829 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
1831 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
1832 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
1833 int load_idx
= sd
->forkexec_idx
;
1834 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
1837 unsigned long load
, avg_load
;
1841 /* Skip over this group if it has no CPUs allowed */
1842 if (!cpus_intersects(group
->cpumask
, p
->cpus_allowed
))
1845 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
1847 /* Tally up the load of all CPUs in the group */
1850 for_each_cpu_mask(i
, group
->cpumask
) {
1851 /* Bias balancing toward cpus of our domain */
1853 load
= source_load(i
, load_idx
);
1855 load
= target_load(i
, load_idx
);
1860 /* Adjust by relative CPU power of the group */
1861 avg_load
= sg_div_cpu_power(group
,
1862 avg_load
* SCHED_LOAD_SCALE
);
1865 this_load
= avg_load
;
1867 } else if (avg_load
< min_load
) {
1868 min_load
= avg_load
;
1871 } while (group
= group
->next
, group
!= sd
->groups
);
1873 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
1879 * find_idlest_cpu - find the idlest cpu among the cpus in group.
1882 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
)
1885 unsigned long load
, min_load
= ULONG_MAX
;
1889 /* Traverse only the allowed CPUs */
1890 cpus_and(tmp
, group
->cpumask
, p
->cpus_allowed
);
1892 for_each_cpu_mask(i
, tmp
) {
1893 load
= weighted_cpuload(i
);
1895 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
1905 * sched_balance_self: balance the current task (running on cpu) in domains
1906 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
1909 * Balance, ie. select the least loaded group.
1911 * Returns the target CPU number, or the same CPU if no balancing is needed.
1913 * preempt must be disabled.
1915 static int sched_balance_self(int cpu
, int flag
)
1917 struct task_struct
*t
= current
;
1918 struct sched_domain
*tmp
, *sd
= NULL
;
1920 for_each_domain(cpu
, tmp
) {
1922 * If power savings logic is enabled for a domain, stop there.
1924 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
1926 if (tmp
->flags
& flag
)
1932 struct sched_group
*group
;
1933 int new_cpu
, weight
;
1935 if (!(sd
->flags
& flag
)) {
1941 group
= find_idlest_group(sd
, t
, cpu
);
1947 new_cpu
= find_idlest_cpu(group
, t
, cpu
);
1948 if (new_cpu
== -1 || new_cpu
== cpu
) {
1949 /* Now try balancing at a lower domain level of cpu */
1954 /* Now try balancing at a lower domain level of new_cpu */
1957 weight
= cpus_weight(span
);
1958 for_each_domain(cpu
, tmp
) {
1959 if (weight
<= cpus_weight(tmp
->span
))
1961 if (tmp
->flags
& flag
)
1964 /* while loop will break here if sd == NULL */
1970 #endif /* CONFIG_SMP */
1973 * try_to_wake_up - wake up a thread
1974 * @p: the to-be-woken-up thread
1975 * @state: the mask of task states that can be woken
1976 * @sync: do a synchronous wakeup?
1978 * Put it on the run-queue if it's not already there. The "current"
1979 * thread is always on the run-queue (except when the actual
1980 * re-schedule is in progress), and as such you're allowed to do
1981 * the simpler "current->state = TASK_RUNNING" to mark yourself
1982 * runnable without the overhead of this.
1984 * returns failure only if the task is already active.
1986 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
1988 int cpu
, orig_cpu
, this_cpu
, success
= 0;
1989 unsigned long flags
;
1993 if (!sched_feat(SYNC_WAKEUPS
))
1997 rq
= task_rq_lock(p
, &flags
);
1998 old_state
= p
->state
;
1999 if (!(old_state
& state
))
2007 this_cpu
= smp_processor_id();
2010 if (unlikely(task_running(rq
, p
)))
2013 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2014 if (cpu
!= orig_cpu
) {
2015 set_task_cpu(p
, cpu
);
2016 task_rq_unlock(rq
, &flags
);
2017 /* might preempt at this point */
2018 rq
= task_rq_lock(p
, &flags
);
2019 old_state
= p
->state
;
2020 if (!(old_state
& state
))
2025 this_cpu
= smp_processor_id();
2029 #ifdef CONFIG_SCHEDSTATS
2030 schedstat_inc(rq
, ttwu_count
);
2031 if (cpu
== this_cpu
)
2032 schedstat_inc(rq
, ttwu_local
);
2034 struct sched_domain
*sd
;
2035 for_each_domain(this_cpu
, sd
) {
2036 if (cpu_isset(cpu
, sd
->span
)) {
2037 schedstat_inc(sd
, ttwu_wake_remote
);
2045 #endif /* CONFIG_SMP */
2046 schedstat_inc(p
, se
.nr_wakeups
);
2048 schedstat_inc(p
, se
.nr_wakeups_sync
);
2049 if (orig_cpu
!= cpu
)
2050 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2051 if (cpu
== this_cpu
)
2052 schedstat_inc(p
, se
.nr_wakeups_local
);
2054 schedstat_inc(p
, se
.nr_wakeups_remote
);
2055 update_rq_clock(rq
);
2056 activate_task(rq
, p
, 1);
2060 check_preempt_curr(rq
, p
);
2062 p
->state
= TASK_RUNNING
;
2064 if (p
->sched_class
->task_wake_up
)
2065 p
->sched_class
->task_wake_up(rq
, p
);
2068 task_rq_unlock(rq
, &flags
);
2073 int wake_up_process(struct task_struct
*p
)
2075 return try_to_wake_up(p
, TASK_ALL
, 0);
2077 EXPORT_SYMBOL(wake_up_process
);
2079 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2081 return try_to_wake_up(p
, state
, 0);
2085 * Perform scheduler related setup for a newly forked process p.
2086 * p is forked by current.
2088 * __sched_fork() is basic setup used by init_idle() too:
2090 static void __sched_fork(struct task_struct
*p
)
2092 p
->se
.exec_start
= 0;
2093 p
->se
.sum_exec_runtime
= 0;
2094 p
->se
.prev_sum_exec_runtime
= 0;
2095 p
->se
.last_wakeup
= 0;
2096 p
->se
.avg_overlap
= 0;
2098 #ifdef CONFIG_SCHEDSTATS
2099 p
->se
.wait_start
= 0;
2100 p
->se
.sum_sleep_runtime
= 0;
2101 p
->se
.sleep_start
= 0;
2102 p
->se
.block_start
= 0;
2103 p
->se
.sleep_max
= 0;
2104 p
->se
.block_max
= 0;
2106 p
->se
.slice_max
= 0;
2110 INIT_LIST_HEAD(&p
->rt
.run_list
);
2113 #ifdef CONFIG_PREEMPT_NOTIFIERS
2114 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2118 * We mark the process as running here, but have not actually
2119 * inserted it onto the runqueue yet. This guarantees that
2120 * nobody will actually run it, and a signal or other external
2121 * event cannot wake it up and insert it on the runqueue either.
2123 p
->state
= TASK_RUNNING
;
2127 * fork()/clone()-time setup:
2129 void sched_fork(struct task_struct
*p
, int clone_flags
)
2131 int cpu
= get_cpu();
2136 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2138 set_task_cpu(p
, cpu
);
2141 * Make sure we do not leak PI boosting priority to the child:
2143 p
->prio
= current
->normal_prio
;
2144 if (!rt_prio(p
->prio
))
2145 p
->sched_class
= &fair_sched_class
;
2147 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2148 if (likely(sched_info_on()))
2149 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2151 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2154 #ifdef CONFIG_PREEMPT
2155 /* Want to start with kernel preemption disabled. */
2156 task_thread_info(p
)->preempt_count
= 1;
2162 * wake_up_new_task - wake up a newly created task for the first time.
2164 * This function will do some initial scheduler statistics housekeeping
2165 * that must be done for every newly created context, then puts the task
2166 * on the runqueue and wakes it.
2168 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2170 unsigned long flags
;
2173 rq
= task_rq_lock(p
, &flags
);
2174 BUG_ON(p
->state
!= TASK_RUNNING
);
2175 update_rq_clock(rq
);
2177 p
->prio
= effective_prio(p
);
2179 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2180 activate_task(rq
, p
, 0);
2183 * Let the scheduling class do new task startup
2184 * management (if any):
2186 p
->sched_class
->task_new(rq
, p
);
2187 inc_nr_running(p
, rq
);
2189 check_preempt_curr(rq
, p
);
2191 if (p
->sched_class
->task_wake_up
)
2192 p
->sched_class
->task_wake_up(rq
, p
);
2194 task_rq_unlock(rq
, &flags
);
2197 #ifdef CONFIG_PREEMPT_NOTIFIERS
2200 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2201 * @notifier: notifier struct to register
2203 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2205 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2207 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2210 * preempt_notifier_unregister - no longer interested in preemption notifications
2211 * @notifier: notifier struct to unregister
2213 * This is safe to call from within a preemption notifier.
2215 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2217 hlist_del(¬ifier
->link
);
2219 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2221 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2223 struct preempt_notifier
*notifier
;
2224 struct hlist_node
*node
;
2226 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2227 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2231 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2232 struct task_struct
*next
)
2234 struct preempt_notifier
*notifier
;
2235 struct hlist_node
*node
;
2237 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2238 notifier
->ops
->sched_out(notifier
, next
);
2243 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2248 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2249 struct task_struct
*next
)
2256 * prepare_task_switch - prepare to switch tasks
2257 * @rq: the runqueue preparing to switch
2258 * @prev: the current task that is being switched out
2259 * @next: the task we are going to switch to.
2261 * This is called with the rq lock held and interrupts off. It must
2262 * be paired with a subsequent finish_task_switch after the context
2265 * prepare_task_switch sets up locking and calls architecture specific
2269 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2270 struct task_struct
*next
)
2272 fire_sched_out_preempt_notifiers(prev
, next
);
2273 prepare_lock_switch(rq
, next
);
2274 prepare_arch_switch(next
);
2278 * finish_task_switch - clean up after a task-switch
2279 * @rq: runqueue associated with task-switch
2280 * @prev: the thread we just switched away from.
2282 * finish_task_switch must be called after the context switch, paired
2283 * with a prepare_task_switch call before the context switch.
2284 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2285 * and do any other architecture-specific cleanup actions.
2287 * Note that we may have delayed dropping an mm in context_switch(). If
2288 * so, we finish that here outside of the runqueue lock. (Doing it
2289 * with the lock held can cause deadlocks; see schedule() for
2292 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2293 __releases(rq
->lock
)
2295 struct mm_struct
*mm
= rq
->prev_mm
;
2301 * A task struct has one reference for the use as "current".
2302 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2303 * schedule one last time. The schedule call will never return, and
2304 * the scheduled task must drop that reference.
2305 * The test for TASK_DEAD must occur while the runqueue locks are
2306 * still held, otherwise prev could be scheduled on another cpu, die
2307 * there before we look at prev->state, and then the reference would
2309 * Manfred Spraul <manfred@colorfullife.com>
2311 prev_state
= prev
->state
;
2312 finish_arch_switch(prev
);
2313 finish_lock_switch(rq
, prev
);
2315 if (current
->sched_class
->post_schedule
)
2316 current
->sched_class
->post_schedule(rq
);
2319 fire_sched_in_preempt_notifiers(current
);
2322 if (unlikely(prev_state
== TASK_DEAD
)) {
2324 * Remove function-return probe instances associated with this
2325 * task and put them back on the free list.
2327 kprobe_flush_task(prev
);
2328 put_task_struct(prev
);
2333 * schedule_tail - first thing a freshly forked thread must call.
2334 * @prev: the thread we just switched away from.
2336 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2337 __releases(rq
->lock
)
2339 struct rq
*rq
= this_rq();
2341 finish_task_switch(rq
, prev
);
2342 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2343 /* In this case, finish_task_switch does not reenable preemption */
2346 if (current
->set_child_tid
)
2347 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2351 * context_switch - switch to the new MM and the new
2352 * thread's register state.
2355 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2356 struct task_struct
*next
)
2358 struct mm_struct
*mm
, *oldmm
;
2360 prepare_task_switch(rq
, prev
, next
);
2362 oldmm
= prev
->active_mm
;
2364 * For paravirt, this is coupled with an exit in switch_to to
2365 * combine the page table reload and the switch backend into
2368 arch_enter_lazy_cpu_mode();
2370 if (unlikely(!mm
)) {
2371 next
->active_mm
= oldmm
;
2372 atomic_inc(&oldmm
->mm_count
);
2373 enter_lazy_tlb(oldmm
, next
);
2375 switch_mm(oldmm
, mm
, next
);
2377 if (unlikely(!prev
->mm
)) {
2378 prev
->active_mm
= NULL
;
2379 rq
->prev_mm
= oldmm
;
2382 * Since the runqueue lock will be released by the next
2383 * task (which is an invalid locking op but in the case
2384 * of the scheduler it's an obvious special-case), so we
2385 * do an early lockdep release here:
2387 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2388 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2391 /* Here we just switch the register state and the stack. */
2392 switch_to(prev
, next
, prev
);
2396 * this_rq must be evaluated again because prev may have moved
2397 * CPUs since it called schedule(), thus the 'rq' on its stack
2398 * frame will be invalid.
2400 finish_task_switch(this_rq(), prev
);
2404 * nr_running, nr_uninterruptible and nr_context_switches:
2406 * externally visible scheduler statistics: current number of runnable
2407 * threads, current number of uninterruptible-sleeping threads, total
2408 * number of context switches performed since bootup.
2410 unsigned long nr_running(void)
2412 unsigned long i
, sum
= 0;
2414 for_each_online_cpu(i
)
2415 sum
+= cpu_rq(i
)->nr_running
;
2420 unsigned long nr_uninterruptible(void)
2422 unsigned long i
, sum
= 0;
2424 for_each_possible_cpu(i
)
2425 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2428 * Since we read the counters lockless, it might be slightly
2429 * inaccurate. Do not allow it to go below zero though:
2431 if (unlikely((long)sum
< 0))
2437 unsigned long long nr_context_switches(void)
2440 unsigned long long sum
= 0;
2442 for_each_possible_cpu(i
)
2443 sum
+= cpu_rq(i
)->nr_switches
;
2448 unsigned long nr_iowait(void)
2450 unsigned long i
, sum
= 0;
2452 for_each_possible_cpu(i
)
2453 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2458 unsigned long nr_active(void)
2460 unsigned long i
, running
= 0, uninterruptible
= 0;
2462 for_each_online_cpu(i
) {
2463 running
+= cpu_rq(i
)->nr_running
;
2464 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2467 if (unlikely((long)uninterruptible
< 0))
2468 uninterruptible
= 0;
2470 return running
+ uninterruptible
;
2474 * Update rq->cpu_load[] statistics. This function is usually called every
2475 * scheduler tick (TICK_NSEC).
2477 static void update_cpu_load(struct rq
*this_rq
)
2479 unsigned long this_load
= this_rq
->load
.weight
;
2482 this_rq
->nr_load_updates
++;
2484 /* Update our load: */
2485 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2486 unsigned long old_load
, new_load
;
2488 /* scale is effectively 1 << i now, and >> i divides by scale */
2490 old_load
= this_rq
->cpu_load
[i
];
2491 new_load
= this_load
;
2493 * Round up the averaging division if load is increasing. This
2494 * prevents us from getting stuck on 9 if the load is 10, for
2497 if (new_load
> old_load
)
2498 new_load
+= scale
-1;
2499 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2506 * double_rq_lock - safely lock two runqueues
2508 * Note this does not disable interrupts like task_rq_lock,
2509 * you need to do so manually before calling.
2511 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2512 __acquires(rq1
->lock
)
2513 __acquires(rq2
->lock
)
2515 BUG_ON(!irqs_disabled());
2517 spin_lock(&rq1
->lock
);
2518 __acquire(rq2
->lock
); /* Fake it out ;) */
2521 spin_lock(&rq1
->lock
);
2522 spin_lock(&rq2
->lock
);
2524 spin_lock(&rq2
->lock
);
2525 spin_lock(&rq1
->lock
);
2528 update_rq_clock(rq1
);
2529 update_rq_clock(rq2
);
2533 * double_rq_unlock - safely unlock two runqueues
2535 * Note this does not restore interrupts like task_rq_unlock,
2536 * you need to do so manually after calling.
2538 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2539 __releases(rq1
->lock
)
2540 __releases(rq2
->lock
)
2542 spin_unlock(&rq1
->lock
);
2544 spin_unlock(&rq2
->lock
);
2546 __release(rq2
->lock
);
2550 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2552 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
2553 __releases(this_rq
->lock
)
2554 __acquires(busiest
->lock
)
2555 __acquires(this_rq
->lock
)
2559 if (unlikely(!irqs_disabled())) {
2560 /* printk() doesn't work good under rq->lock */
2561 spin_unlock(&this_rq
->lock
);
2564 if (unlikely(!spin_trylock(&busiest
->lock
))) {
2565 if (busiest
< this_rq
) {
2566 spin_unlock(&this_rq
->lock
);
2567 spin_lock(&busiest
->lock
);
2568 spin_lock(&this_rq
->lock
);
2571 spin_lock(&busiest
->lock
);
2577 * If dest_cpu is allowed for this process, migrate the task to it.
2578 * This is accomplished by forcing the cpu_allowed mask to only
2579 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2580 * the cpu_allowed mask is restored.
2582 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2584 struct migration_req req
;
2585 unsigned long flags
;
2588 rq
= task_rq_lock(p
, &flags
);
2589 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
)
2590 || unlikely(cpu_is_offline(dest_cpu
)))
2593 /* force the process onto the specified CPU */
2594 if (migrate_task(p
, dest_cpu
, &req
)) {
2595 /* Need to wait for migration thread (might exit: take ref). */
2596 struct task_struct
*mt
= rq
->migration_thread
;
2598 get_task_struct(mt
);
2599 task_rq_unlock(rq
, &flags
);
2600 wake_up_process(mt
);
2601 put_task_struct(mt
);
2602 wait_for_completion(&req
.done
);
2607 task_rq_unlock(rq
, &flags
);
2611 * sched_exec - execve() is a valuable balancing opportunity, because at
2612 * this point the task has the smallest effective memory and cache footprint.
2614 void sched_exec(void)
2616 int new_cpu
, this_cpu
= get_cpu();
2617 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2619 if (new_cpu
!= this_cpu
)
2620 sched_migrate_task(current
, new_cpu
);
2624 * pull_task - move a task from a remote runqueue to the local runqueue.
2625 * Both runqueues must be locked.
2627 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2628 struct rq
*this_rq
, int this_cpu
)
2630 deactivate_task(src_rq
, p
, 0);
2631 set_task_cpu(p
, this_cpu
);
2632 activate_task(this_rq
, p
, 0);
2634 * Note that idle threads have a prio of MAX_PRIO, for this test
2635 * to be always true for them.
2637 check_preempt_curr(this_rq
, p
);
2641 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2644 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2645 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2649 * We do not migrate tasks that are:
2650 * 1) running (obviously), or
2651 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2652 * 3) are cache-hot on their current CPU.
2654 if (!cpu_isset(this_cpu
, p
->cpus_allowed
)) {
2655 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
2660 if (task_running(rq
, p
)) {
2661 schedstat_inc(p
, se
.nr_failed_migrations_running
);
2666 * Aggressive migration if:
2667 * 1) task is cache cold, or
2668 * 2) too many balance attempts have failed.
2671 if (!task_hot(p
, rq
->clock
, sd
) ||
2672 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
2673 #ifdef CONFIG_SCHEDSTATS
2674 if (task_hot(p
, rq
->clock
, sd
)) {
2675 schedstat_inc(sd
, lb_hot_gained
[idle
]);
2676 schedstat_inc(p
, se
.nr_forced_migrations
);
2682 if (task_hot(p
, rq
->clock
, sd
)) {
2683 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
2689 static unsigned long
2690 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2691 unsigned long max_load_move
, struct sched_domain
*sd
,
2692 enum cpu_idle_type idle
, int *all_pinned
,
2693 int *this_best_prio
, struct rq_iterator
*iterator
)
2695 int loops
= 0, pulled
= 0, pinned
= 0, skip_for_load
;
2696 struct task_struct
*p
;
2697 long rem_load_move
= max_load_move
;
2699 if (max_load_move
== 0)
2705 * Start the load-balancing iterator:
2707 p
= iterator
->start(iterator
->arg
);
2709 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
2712 * To help distribute high priority tasks across CPUs we don't
2713 * skip a task if it will be the highest priority task (i.e. smallest
2714 * prio value) on its new queue regardless of its load weight
2716 skip_for_load
= (p
->se
.load
.weight
>> 1) > rem_load_move
+
2717 SCHED_LOAD_SCALE_FUZZ
;
2718 if ((skip_for_load
&& p
->prio
>= *this_best_prio
) ||
2719 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2720 p
= iterator
->next(iterator
->arg
);
2724 pull_task(busiest
, p
, this_rq
, this_cpu
);
2726 rem_load_move
-= p
->se
.load
.weight
;
2729 * We only want to steal up to the prescribed amount of weighted load.
2731 if (rem_load_move
> 0) {
2732 if (p
->prio
< *this_best_prio
)
2733 *this_best_prio
= p
->prio
;
2734 p
= iterator
->next(iterator
->arg
);
2739 * Right now, this is one of only two places pull_task() is called,
2740 * so we can safely collect pull_task() stats here rather than
2741 * inside pull_task().
2743 schedstat_add(sd
, lb_gained
[idle
], pulled
);
2746 *all_pinned
= pinned
;
2748 return max_load_move
- rem_load_move
;
2752 * move_tasks tries to move up to max_load_move weighted load from busiest to
2753 * this_rq, as part of a balancing operation within domain "sd".
2754 * Returns 1 if successful and 0 otherwise.
2756 * Called with both runqueues locked.
2758 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2759 unsigned long max_load_move
,
2760 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2763 const struct sched_class
*class = sched_class_highest
;
2764 unsigned long total_load_moved
= 0;
2765 int this_best_prio
= this_rq
->curr
->prio
;
2769 class->load_balance(this_rq
, this_cpu
, busiest
,
2770 max_load_move
- total_load_moved
,
2771 sd
, idle
, all_pinned
, &this_best_prio
);
2772 class = class->next
;
2773 } while (class && max_load_move
> total_load_moved
);
2775 return total_load_moved
> 0;
2779 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2780 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2781 struct rq_iterator
*iterator
)
2783 struct task_struct
*p
= iterator
->start(iterator
->arg
);
2787 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2788 pull_task(busiest
, p
, this_rq
, this_cpu
);
2790 * Right now, this is only the second place pull_task()
2791 * is called, so we can safely collect pull_task()
2792 * stats here rather than inside pull_task().
2794 schedstat_inc(sd
, lb_gained
[idle
]);
2798 p
= iterator
->next(iterator
->arg
);
2805 * move_one_task tries to move exactly one task from busiest to this_rq, as
2806 * part of active balancing operations within "domain".
2807 * Returns 1 if successful and 0 otherwise.
2809 * Called with both runqueues locked.
2811 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2812 struct sched_domain
*sd
, enum cpu_idle_type idle
)
2814 const struct sched_class
*class;
2816 for (class = sched_class_highest
; class; class = class->next
)
2817 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
2824 * find_busiest_group finds and returns the busiest CPU group within the
2825 * domain. It calculates and returns the amount of weighted load which
2826 * should be moved to restore balance via the imbalance parameter.
2828 static struct sched_group
*
2829 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
2830 unsigned long *imbalance
, enum cpu_idle_type idle
,
2831 int *sd_idle
, cpumask_t
*cpus
, int *balance
)
2833 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2834 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
2835 unsigned long max_pull
;
2836 unsigned long busiest_load_per_task
, busiest_nr_running
;
2837 unsigned long this_load_per_task
, this_nr_running
;
2838 int load_idx
, group_imb
= 0;
2839 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2840 int power_savings_balance
= 1;
2841 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
2842 unsigned long min_nr_running
= ULONG_MAX
;
2843 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
2846 max_load
= this_load
= total_load
= total_pwr
= 0;
2847 busiest_load_per_task
= busiest_nr_running
= 0;
2848 this_load_per_task
= this_nr_running
= 0;
2849 if (idle
== CPU_NOT_IDLE
)
2850 load_idx
= sd
->busy_idx
;
2851 else if (idle
== CPU_NEWLY_IDLE
)
2852 load_idx
= sd
->newidle_idx
;
2854 load_idx
= sd
->idle_idx
;
2857 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
2860 int __group_imb
= 0;
2861 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
2862 unsigned long sum_nr_running
, sum_weighted_load
;
2864 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
2867 balance_cpu
= first_cpu(group
->cpumask
);
2869 /* Tally up the load of all CPUs in the group */
2870 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
2872 min_cpu_load
= ~0UL;
2874 for_each_cpu_mask(i
, group
->cpumask
) {
2877 if (!cpu_isset(i
, *cpus
))
2882 if (*sd_idle
&& rq
->nr_running
)
2885 /* Bias balancing toward cpus of our domain */
2887 if (idle_cpu(i
) && !first_idle_cpu
) {
2892 load
= target_load(i
, load_idx
);
2894 load
= source_load(i
, load_idx
);
2895 if (load
> max_cpu_load
)
2896 max_cpu_load
= load
;
2897 if (min_cpu_load
> load
)
2898 min_cpu_load
= load
;
2902 sum_nr_running
+= rq
->nr_running
;
2903 sum_weighted_load
+= weighted_cpuload(i
);
2907 * First idle cpu or the first cpu(busiest) in this sched group
2908 * is eligible for doing load balancing at this and above
2909 * domains. In the newly idle case, we will allow all the cpu's
2910 * to do the newly idle load balance.
2912 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
2913 balance_cpu
!= this_cpu
&& balance
) {
2918 total_load
+= avg_load
;
2919 total_pwr
+= group
->__cpu_power
;
2921 /* Adjust by relative CPU power of the group */
2922 avg_load
= sg_div_cpu_power(group
,
2923 avg_load
* SCHED_LOAD_SCALE
);
2925 if ((max_cpu_load
- min_cpu_load
) > SCHED_LOAD_SCALE
)
2928 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
2931 this_load
= avg_load
;
2933 this_nr_running
= sum_nr_running
;
2934 this_load_per_task
= sum_weighted_load
;
2935 } else if (avg_load
> max_load
&&
2936 (sum_nr_running
> group_capacity
|| __group_imb
)) {
2937 max_load
= avg_load
;
2939 busiest_nr_running
= sum_nr_running
;
2940 busiest_load_per_task
= sum_weighted_load
;
2941 group_imb
= __group_imb
;
2944 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2946 * Busy processors will not participate in power savings
2949 if (idle
== CPU_NOT_IDLE
||
2950 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
2954 * If the local group is idle or completely loaded
2955 * no need to do power savings balance at this domain
2957 if (local_group
&& (this_nr_running
>= group_capacity
||
2959 power_savings_balance
= 0;
2962 * If a group is already running at full capacity or idle,
2963 * don't include that group in power savings calculations
2965 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
2970 * Calculate the group which has the least non-idle load.
2971 * This is the group from where we need to pick up the load
2974 if ((sum_nr_running
< min_nr_running
) ||
2975 (sum_nr_running
== min_nr_running
&&
2976 first_cpu(group
->cpumask
) <
2977 first_cpu(group_min
->cpumask
))) {
2979 min_nr_running
= sum_nr_running
;
2980 min_load_per_task
= sum_weighted_load
/
2985 * Calculate the group which is almost near its
2986 * capacity but still has some space to pick up some load
2987 * from other group and save more power
2989 if (sum_nr_running
<= group_capacity
- 1) {
2990 if (sum_nr_running
> leader_nr_running
||
2991 (sum_nr_running
== leader_nr_running
&&
2992 first_cpu(group
->cpumask
) >
2993 first_cpu(group_leader
->cpumask
))) {
2994 group_leader
= group
;
2995 leader_nr_running
= sum_nr_running
;
3000 group
= group
->next
;
3001 } while (group
!= sd
->groups
);
3003 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3006 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3008 if (this_load
>= avg_load
||
3009 100*max_load
<= sd
->imbalance_pct
*this_load
)
3012 busiest_load_per_task
/= busiest_nr_running
;
3014 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3017 * We're trying to get all the cpus to the average_load, so we don't
3018 * want to push ourselves above the average load, nor do we wish to
3019 * reduce the max loaded cpu below the average load, as either of these
3020 * actions would just result in more rebalancing later, and ping-pong
3021 * tasks around. Thus we look for the minimum possible imbalance.
3022 * Negative imbalances (*we* are more loaded than anyone else) will
3023 * be counted as no imbalance for these purposes -- we can't fix that
3024 * by pulling tasks to us. Be careful of negative numbers as they'll
3025 * appear as very large values with unsigned longs.
3027 if (max_load
<= busiest_load_per_task
)
3031 * In the presence of smp nice balancing, certain scenarios can have
3032 * max load less than avg load(as we skip the groups at or below
3033 * its cpu_power, while calculating max_load..)
3035 if (max_load
< avg_load
) {
3037 goto small_imbalance
;
3040 /* Don't want to pull so many tasks that a group would go idle */
3041 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3043 /* How much load to actually move to equalise the imbalance */
3044 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3045 (avg_load
- this_load
) * this->__cpu_power
)
3049 * if *imbalance is less than the average load per runnable task
3050 * there is no gaurantee that any tasks will be moved so we'll have
3051 * a think about bumping its value to force at least one task to be
3054 if (*imbalance
< busiest_load_per_task
) {
3055 unsigned long tmp
, pwr_now
, pwr_move
;
3059 pwr_move
= pwr_now
= 0;
3061 if (this_nr_running
) {
3062 this_load_per_task
/= this_nr_running
;
3063 if (busiest_load_per_task
> this_load_per_task
)
3066 this_load_per_task
= SCHED_LOAD_SCALE
;
3068 if (max_load
- this_load
+ SCHED_LOAD_SCALE_FUZZ
>=
3069 busiest_load_per_task
* imbn
) {
3070 *imbalance
= busiest_load_per_task
;
3075 * OK, we don't have enough imbalance to justify moving tasks,
3076 * however we may be able to increase total CPU power used by
3080 pwr_now
+= busiest
->__cpu_power
*
3081 min(busiest_load_per_task
, max_load
);
3082 pwr_now
+= this->__cpu_power
*
3083 min(this_load_per_task
, this_load
);
3084 pwr_now
/= SCHED_LOAD_SCALE
;
3086 /* Amount of load we'd subtract */
3087 tmp
= sg_div_cpu_power(busiest
,
3088 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3090 pwr_move
+= busiest
->__cpu_power
*
3091 min(busiest_load_per_task
, max_load
- tmp
);
3093 /* Amount of load we'd add */
3094 if (max_load
* busiest
->__cpu_power
<
3095 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3096 tmp
= sg_div_cpu_power(this,
3097 max_load
* busiest
->__cpu_power
);
3099 tmp
= sg_div_cpu_power(this,
3100 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3101 pwr_move
+= this->__cpu_power
*
3102 min(this_load_per_task
, this_load
+ tmp
);
3103 pwr_move
/= SCHED_LOAD_SCALE
;
3105 /* Move if we gain throughput */
3106 if (pwr_move
> pwr_now
)
3107 *imbalance
= busiest_load_per_task
;
3113 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3114 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3117 if (this == group_leader
&& group_leader
!= group_min
) {
3118 *imbalance
= min_load_per_task
;
3128 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3131 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3132 unsigned long imbalance
, cpumask_t
*cpus
)
3134 struct rq
*busiest
= NULL
, *rq
;
3135 unsigned long max_load
= 0;
3138 for_each_cpu_mask(i
, group
->cpumask
) {
3141 if (!cpu_isset(i
, *cpus
))
3145 wl
= weighted_cpuload(i
);
3147 if (rq
->nr_running
== 1 && wl
> imbalance
)
3150 if (wl
> max_load
) {
3160 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3161 * so long as it is large enough.
3163 #define MAX_PINNED_INTERVAL 512
3166 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3167 * tasks if there is an imbalance.
3169 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3170 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3173 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3174 struct sched_group
*group
;
3175 unsigned long imbalance
;
3177 cpumask_t cpus
= CPU_MASK_ALL
;
3178 unsigned long flags
;
3181 * When power savings policy is enabled for the parent domain, idle
3182 * sibling can pick up load irrespective of busy siblings. In this case,
3183 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3184 * portraying it as CPU_NOT_IDLE.
3186 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3187 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3190 schedstat_inc(sd
, lb_count
[idle
]);
3193 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3200 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3204 busiest
= find_busiest_queue(group
, idle
, imbalance
, &cpus
);
3206 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3210 BUG_ON(busiest
== this_rq
);
3212 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3215 if (busiest
->nr_running
> 1) {
3217 * Attempt to move tasks. If find_busiest_group has found
3218 * an imbalance but busiest->nr_running <= 1, the group is
3219 * still unbalanced. ld_moved simply stays zero, so it is
3220 * correctly treated as an imbalance.
3222 local_irq_save(flags
);
3223 double_rq_lock(this_rq
, busiest
);
3224 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3225 imbalance
, sd
, idle
, &all_pinned
);
3226 double_rq_unlock(this_rq
, busiest
);
3227 local_irq_restore(flags
);
3230 * some other cpu did the load balance for us.
3232 if (ld_moved
&& this_cpu
!= smp_processor_id())
3233 resched_cpu(this_cpu
);
3235 /* All tasks on this runqueue were pinned by CPU affinity */
3236 if (unlikely(all_pinned
)) {
3237 cpu_clear(cpu_of(busiest
), cpus
);
3238 if (!cpus_empty(cpus
))
3245 schedstat_inc(sd
, lb_failed
[idle
]);
3246 sd
->nr_balance_failed
++;
3248 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3250 spin_lock_irqsave(&busiest
->lock
, flags
);
3252 /* don't kick the migration_thread, if the curr
3253 * task on busiest cpu can't be moved to this_cpu
3255 if (!cpu_isset(this_cpu
, busiest
->curr
->cpus_allowed
)) {
3256 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3258 goto out_one_pinned
;
3261 if (!busiest
->active_balance
) {
3262 busiest
->active_balance
= 1;
3263 busiest
->push_cpu
= this_cpu
;
3266 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3268 wake_up_process(busiest
->migration_thread
);
3271 * We've kicked active balancing, reset the failure
3274 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3277 sd
->nr_balance_failed
= 0;
3279 if (likely(!active_balance
)) {
3280 /* We were unbalanced, so reset the balancing interval */
3281 sd
->balance_interval
= sd
->min_interval
;
3284 * If we've begun active balancing, start to back off. This
3285 * case may not be covered by the all_pinned logic if there
3286 * is only 1 task on the busy runqueue (because we don't call
3289 if (sd
->balance_interval
< sd
->max_interval
)
3290 sd
->balance_interval
*= 2;
3293 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3294 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3299 schedstat_inc(sd
, lb_balanced
[idle
]);
3301 sd
->nr_balance_failed
= 0;
3304 /* tune up the balancing interval */
3305 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3306 (sd
->balance_interval
< sd
->max_interval
))
3307 sd
->balance_interval
*= 2;
3309 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3310 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3316 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3317 * tasks if there is an imbalance.
3319 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3320 * this_rq is locked.
3323 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
)
3325 struct sched_group
*group
;
3326 struct rq
*busiest
= NULL
;
3327 unsigned long imbalance
;
3331 cpumask_t cpus
= CPU_MASK_ALL
;
3334 * When power savings policy is enabled for the parent domain, idle
3335 * sibling can pick up load irrespective of busy siblings. In this case,
3336 * let the state of idle sibling percolate up as IDLE, instead of
3337 * portraying it as CPU_NOT_IDLE.
3339 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3340 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3343 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3345 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3346 &sd_idle
, &cpus
, NULL
);
3348 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3352 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
,
3355 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3359 BUG_ON(busiest
== this_rq
);
3361 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3364 if (busiest
->nr_running
> 1) {
3365 /* Attempt to move tasks */
3366 double_lock_balance(this_rq
, busiest
);
3367 /* this_rq->clock is already updated */
3368 update_rq_clock(busiest
);
3369 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3370 imbalance
, sd
, CPU_NEWLY_IDLE
,
3372 spin_unlock(&busiest
->lock
);
3374 if (unlikely(all_pinned
)) {
3375 cpu_clear(cpu_of(busiest
), cpus
);
3376 if (!cpus_empty(cpus
))
3382 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3383 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3384 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3387 sd
->nr_balance_failed
= 0;
3392 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3393 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3394 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3396 sd
->nr_balance_failed
= 0;
3402 * idle_balance is called by schedule() if this_cpu is about to become
3403 * idle. Attempts to pull tasks from other CPUs.
3405 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3407 struct sched_domain
*sd
;
3408 int pulled_task
= -1;
3409 unsigned long next_balance
= jiffies
+ HZ
;
3411 for_each_domain(this_cpu
, sd
) {
3412 unsigned long interval
;
3414 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3417 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3418 /* If we've pulled tasks over stop searching: */
3419 pulled_task
= load_balance_newidle(this_cpu
,
3422 interval
= msecs_to_jiffies(sd
->balance_interval
);
3423 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3424 next_balance
= sd
->last_balance
+ interval
;
3428 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3430 * We are going idle. next_balance may be set based on
3431 * a busy processor. So reset next_balance.
3433 this_rq
->next_balance
= next_balance
;
3438 * active_load_balance is run by migration threads. It pushes running tasks
3439 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3440 * running on each physical CPU where possible, and avoids physical /
3441 * logical imbalances.
3443 * Called with busiest_rq locked.
3445 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3447 int target_cpu
= busiest_rq
->push_cpu
;
3448 struct sched_domain
*sd
;
3449 struct rq
*target_rq
;
3451 /* Is there any task to move? */
3452 if (busiest_rq
->nr_running
<= 1)
3455 target_rq
= cpu_rq(target_cpu
);
3458 * This condition is "impossible", if it occurs
3459 * we need to fix it. Originally reported by
3460 * Bjorn Helgaas on a 128-cpu setup.
3462 BUG_ON(busiest_rq
== target_rq
);
3464 /* move a task from busiest_rq to target_rq */
3465 double_lock_balance(busiest_rq
, target_rq
);
3466 update_rq_clock(busiest_rq
);
3467 update_rq_clock(target_rq
);
3469 /* Search for an sd spanning us and the target CPU. */
3470 for_each_domain(target_cpu
, sd
) {
3471 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3472 cpu_isset(busiest_cpu
, sd
->span
))
3477 schedstat_inc(sd
, alb_count
);
3479 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3481 schedstat_inc(sd
, alb_pushed
);
3483 schedstat_inc(sd
, alb_failed
);
3485 spin_unlock(&target_rq
->lock
);
3490 atomic_t load_balancer
;
3492 } nohz ____cacheline_aligned
= {
3493 .load_balancer
= ATOMIC_INIT(-1),
3494 .cpu_mask
= CPU_MASK_NONE
,
3498 * This routine will try to nominate the ilb (idle load balancing)
3499 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3500 * load balancing on behalf of all those cpus. If all the cpus in the system
3501 * go into this tickless mode, then there will be no ilb owner (as there is
3502 * no need for one) and all the cpus will sleep till the next wakeup event
3505 * For the ilb owner, tick is not stopped. And this tick will be used
3506 * for idle load balancing. ilb owner will still be part of
3509 * While stopping the tick, this cpu will become the ilb owner if there
3510 * is no other owner. And will be the owner till that cpu becomes busy
3511 * or if all cpus in the system stop their ticks at which point
3512 * there is no need for ilb owner.
3514 * When the ilb owner becomes busy, it nominates another owner, during the
3515 * next busy scheduler_tick()
3517 int select_nohz_load_balancer(int stop_tick
)
3519 int cpu
= smp_processor_id();
3522 cpu_set(cpu
, nohz
.cpu_mask
);
3523 cpu_rq(cpu
)->in_nohz_recently
= 1;
3526 * If we are going offline and still the leader, give up!
3528 if (cpu_is_offline(cpu
) &&
3529 atomic_read(&nohz
.load_balancer
) == cpu
) {
3530 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3535 /* time for ilb owner also to sleep */
3536 if (cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3537 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3538 atomic_set(&nohz
.load_balancer
, -1);
3542 if (atomic_read(&nohz
.load_balancer
) == -1) {
3543 /* make me the ilb owner */
3544 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
3546 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
3549 if (!cpu_isset(cpu
, nohz
.cpu_mask
))
3552 cpu_clear(cpu
, nohz
.cpu_mask
);
3554 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3555 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3562 static DEFINE_SPINLOCK(balancing
);
3565 * It checks each scheduling domain to see if it is due to be balanced,
3566 * and initiates a balancing operation if so.
3568 * Balancing parameters are set up in arch_init_sched_domains.
3570 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
3573 struct rq
*rq
= cpu_rq(cpu
);
3574 unsigned long interval
;
3575 struct sched_domain
*sd
;
3576 /* Earliest time when we have to do rebalance again */
3577 unsigned long next_balance
= jiffies
+ 60*HZ
;
3578 int update_next_balance
= 0;
3580 for_each_domain(cpu
, sd
) {
3581 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3584 interval
= sd
->balance_interval
;
3585 if (idle
!= CPU_IDLE
)
3586 interval
*= sd
->busy_factor
;
3588 /* scale ms to jiffies */
3589 interval
= msecs_to_jiffies(interval
);
3590 if (unlikely(!interval
))
3592 if (interval
> HZ
*NR_CPUS
/10)
3593 interval
= HZ
*NR_CPUS
/10;
3596 if (sd
->flags
& SD_SERIALIZE
) {
3597 if (!spin_trylock(&balancing
))
3601 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
3602 if (load_balance(cpu
, rq
, sd
, idle
, &balance
)) {
3604 * We've pulled tasks over so either we're no
3605 * longer idle, or one of our SMT siblings is
3608 idle
= CPU_NOT_IDLE
;
3610 sd
->last_balance
= jiffies
;
3612 if (sd
->flags
& SD_SERIALIZE
)
3613 spin_unlock(&balancing
);
3615 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
3616 next_balance
= sd
->last_balance
+ interval
;
3617 update_next_balance
= 1;
3621 * Stop the load balance at this level. There is another
3622 * CPU in our sched group which is doing load balancing more
3630 * next_balance will be updated only when there is a need.
3631 * When the cpu is attached to null domain for ex, it will not be
3634 if (likely(update_next_balance
))
3635 rq
->next_balance
= next_balance
;
3639 * run_rebalance_domains is triggered when needed from the scheduler tick.
3640 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3641 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3643 static void run_rebalance_domains(struct softirq_action
*h
)
3645 int this_cpu
= smp_processor_id();
3646 struct rq
*this_rq
= cpu_rq(this_cpu
);
3647 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
3648 CPU_IDLE
: CPU_NOT_IDLE
;
3650 rebalance_domains(this_cpu
, idle
);
3654 * If this cpu is the owner for idle load balancing, then do the
3655 * balancing on behalf of the other idle cpus whose ticks are
3658 if (this_rq
->idle_at_tick
&&
3659 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
3660 cpumask_t cpus
= nohz
.cpu_mask
;
3664 cpu_clear(this_cpu
, cpus
);
3665 for_each_cpu_mask(balance_cpu
, cpus
) {
3667 * If this cpu gets work to do, stop the load balancing
3668 * work being done for other cpus. Next load
3669 * balancing owner will pick it up.
3674 rebalance_domains(balance_cpu
, CPU_IDLE
);
3676 rq
= cpu_rq(balance_cpu
);
3677 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
3678 this_rq
->next_balance
= rq
->next_balance
;
3685 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3687 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3688 * idle load balancing owner or decide to stop the periodic load balancing,
3689 * if the whole system is idle.
3691 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
3695 * If we were in the nohz mode recently and busy at the current
3696 * scheduler tick, then check if we need to nominate new idle
3699 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
3700 rq
->in_nohz_recently
= 0;
3702 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
3703 cpu_clear(cpu
, nohz
.cpu_mask
);
3704 atomic_set(&nohz
.load_balancer
, -1);
3707 if (atomic_read(&nohz
.load_balancer
) == -1) {
3709 * simple selection for now: Nominate the
3710 * first cpu in the nohz list to be the next
3713 * TBD: Traverse the sched domains and nominate
3714 * the nearest cpu in the nohz.cpu_mask.
3716 int ilb
= first_cpu(nohz
.cpu_mask
);
3724 * If this cpu is idle and doing idle load balancing for all the
3725 * cpus with ticks stopped, is it time for that to stop?
3727 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
3728 cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3734 * If this cpu is idle and the idle load balancing is done by
3735 * someone else, then no need raise the SCHED_SOFTIRQ
3737 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
3738 cpu_isset(cpu
, nohz
.cpu_mask
))
3741 if (time_after_eq(jiffies
, rq
->next_balance
))
3742 raise_softirq(SCHED_SOFTIRQ
);
3745 #else /* CONFIG_SMP */
3748 * on UP we do not need to balance between CPUs:
3750 static inline void idle_balance(int cpu
, struct rq
*rq
)
3756 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3758 EXPORT_PER_CPU_SYMBOL(kstat
);
3761 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3762 * that have not yet been banked in case the task is currently running.
3764 unsigned long long task_sched_runtime(struct task_struct
*p
)
3766 unsigned long flags
;
3770 rq
= task_rq_lock(p
, &flags
);
3771 ns
= p
->se
.sum_exec_runtime
;
3772 if (task_current(rq
, p
)) {
3773 update_rq_clock(rq
);
3774 delta_exec
= rq
->clock
- p
->se
.exec_start
;
3775 if ((s64
)delta_exec
> 0)
3778 task_rq_unlock(rq
, &flags
);
3784 * Account user cpu time to a process.
3785 * @p: the process that the cpu time gets accounted to
3786 * @cputime: the cpu time spent in user space since the last update
3788 void account_user_time(struct task_struct
*p
, cputime_t cputime
)
3790 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3793 p
->utime
= cputime_add(p
->utime
, cputime
);
3795 /* Add user time to cpustat. */
3796 tmp
= cputime_to_cputime64(cputime
);
3797 if (TASK_NICE(p
) > 0)
3798 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3800 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3804 * Account guest cpu time to a process.
3805 * @p: the process that the cpu time gets accounted to
3806 * @cputime: the cpu time spent in virtual machine since the last update
3808 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
)
3811 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3813 tmp
= cputime_to_cputime64(cputime
);
3815 p
->utime
= cputime_add(p
->utime
, cputime
);
3816 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3818 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3819 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3823 * Account scaled user cpu time to a process.
3824 * @p: the process that the cpu time gets accounted to
3825 * @cputime: the cpu time spent in user space since the last update
3827 void account_user_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3829 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime
);
3833 * Account system cpu time to a process.
3834 * @p: the process that the cpu time gets accounted to
3835 * @hardirq_offset: the offset to subtract from hardirq_count()
3836 * @cputime: the cpu time spent in kernel space since the last update
3838 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3841 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3842 struct rq
*rq
= this_rq();
3845 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0))
3846 return account_guest_time(p
, cputime
);
3848 p
->stime
= cputime_add(p
->stime
, cputime
);
3850 /* Add system time to cpustat. */
3851 tmp
= cputime_to_cputime64(cputime
);
3852 if (hardirq_count() - hardirq_offset
)
3853 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3854 else if (softirq_count())
3855 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3856 else if (p
!= rq
->idle
)
3857 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3858 else if (atomic_read(&rq
->nr_iowait
) > 0)
3859 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3861 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3862 /* Account for system time used */
3863 acct_update_integrals(p
);
3867 * Account scaled system cpu time to a process.
3868 * @p: the process that the cpu time gets accounted to
3869 * @hardirq_offset: the offset to subtract from hardirq_count()
3870 * @cputime: the cpu time spent in kernel space since the last update
3872 void account_system_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3874 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime
);
3878 * Account for involuntary wait time.
3879 * @p: the process from which the cpu time has been stolen
3880 * @steal: the cpu time spent in involuntary wait
3882 void account_steal_time(struct task_struct
*p
, cputime_t steal
)
3884 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3885 cputime64_t tmp
= cputime_to_cputime64(steal
);
3886 struct rq
*rq
= this_rq();
3888 if (p
== rq
->idle
) {
3889 p
->stime
= cputime_add(p
->stime
, steal
);
3890 if (atomic_read(&rq
->nr_iowait
) > 0)
3891 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3893 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3895 cpustat
->steal
= cputime64_add(cpustat
->steal
, tmp
);
3899 * This function gets called by the timer code, with HZ frequency.
3900 * We call it with interrupts disabled.
3902 * It also gets called by the fork code, when changing the parent's
3905 void scheduler_tick(void)
3907 int cpu
= smp_processor_id();
3908 struct rq
*rq
= cpu_rq(cpu
);
3909 struct task_struct
*curr
= rq
->curr
;
3910 u64 next_tick
= rq
->tick_timestamp
+ TICK_NSEC
;
3912 spin_lock(&rq
->lock
);
3913 __update_rq_clock(rq
);
3915 * Let rq->clock advance by at least TICK_NSEC:
3917 if (unlikely(rq
->clock
< next_tick
)) {
3918 rq
->clock
= next_tick
;
3919 rq
->clock_underflows
++;
3921 rq
->tick_timestamp
= rq
->clock
;
3922 update_last_tick_seen(rq
);
3923 update_cpu_load(rq
);
3924 curr
->sched_class
->task_tick(rq
, curr
, 0);
3925 spin_unlock(&rq
->lock
);
3928 rq
->idle_at_tick
= idle_cpu(cpu
);
3929 trigger_load_balance(rq
, cpu
);
3933 #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
3935 void __kprobes
add_preempt_count(int val
)
3940 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3942 preempt_count() += val
;
3944 * Spinlock count overflowing soon?
3946 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3949 EXPORT_SYMBOL(add_preempt_count
);
3951 void __kprobes
sub_preempt_count(int val
)
3956 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3959 * Is the spinlock portion underflowing?
3961 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3962 !(preempt_count() & PREEMPT_MASK
)))
3965 preempt_count() -= val
;
3967 EXPORT_SYMBOL(sub_preempt_count
);
3972 * Print scheduling while atomic bug:
3974 static noinline
void __schedule_bug(struct task_struct
*prev
)
3976 struct pt_regs
*regs
= get_irq_regs();
3978 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3979 prev
->comm
, prev
->pid
, preempt_count());
3981 debug_show_held_locks(prev
);
3982 if (irqs_disabled())
3983 print_irqtrace_events(prev
);
3992 * Various schedule()-time debugging checks and statistics:
3994 static inline void schedule_debug(struct task_struct
*prev
)
3997 * Test if we are atomic. Since do_exit() needs to call into
3998 * schedule() atomically, we ignore that path for now.
3999 * Otherwise, whine if we are scheduling when we should not be.
4001 if (unlikely(in_atomic_preempt_off()) && unlikely(!prev
->exit_state
))
4002 __schedule_bug(prev
);
4004 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4006 schedstat_inc(this_rq(), sched_count
);
4007 #ifdef CONFIG_SCHEDSTATS
4008 if (unlikely(prev
->lock_depth
>= 0)) {
4009 schedstat_inc(this_rq(), bkl_count
);
4010 schedstat_inc(prev
, sched_info
.bkl_count
);
4016 * Pick up the highest-prio task:
4018 static inline struct task_struct
*
4019 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4021 const struct sched_class
*class;
4022 struct task_struct
*p
;
4025 * Optimization: we know that if all tasks are in
4026 * the fair class we can call that function directly:
4028 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4029 p
= fair_sched_class
.pick_next_task(rq
);
4034 class = sched_class_highest
;
4036 p
= class->pick_next_task(rq
);
4040 * Will never be NULL as the idle class always
4041 * returns a non-NULL p:
4043 class = class->next
;
4048 * schedule() is the main scheduler function.
4050 asmlinkage
void __sched
schedule(void)
4052 struct task_struct
*prev
, *next
;
4053 unsigned long *switch_count
;
4059 cpu
= smp_processor_id();
4063 switch_count
= &prev
->nivcsw
;
4065 release_kernel_lock(prev
);
4066 need_resched_nonpreemptible
:
4068 schedule_debug(prev
);
4073 * Do the rq-clock update outside the rq lock:
4075 local_irq_disable();
4076 __update_rq_clock(rq
);
4077 spin_lock(&rq
->lock
);
4078 clear_tsk_need_resched(prev
);
4080 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4081 if (unlikely((prev
->state
& TASK_INTERRUPTIBLE
) &&
4082 signal_pending(prev
))) {
4083 prev
->state
= TASK_RUNNING
;
4085 deactivate_task(rq
, prev
, 1);
4087 switch_count
= &prev
->nvcsw
;
4091 if (prev
->sched_class
->pre_schedule
)
4092 prev
->sched_class
->pre_schedule(rq
, prev
);
4095 if (unlikely(!rq
->nr_running
))
4096 idle_balance(cpu
, rq
);
4098 prev
->sched_class
->put_prev_task(rq
, prev
);
4099 next
= pick_next_task(rq
, prev
);
4101 sched_info_switch(prev
, next
);
4103 if (likely(prev
!= next
)) {
4108 context_switch(rq
, prev
, next
); /* unlocks the rq */
4110 * the context switch might have flipped the stack from under
4111 * us, hence refresh the local variables.
4113 cpu
= smp_processor_id();
4116 spin_unlock_irq(&rq
->lock
);
4120 if (unlikely(reacquire_kernel_lock(current
) < 0))
4121 goto need_resched_nonpreemptible
;
4123 preempt_enable_no_resched();
4124 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4127 EXPORT_SYMBOL(schedule
);
4129 #ifdef CONFIG_PREEMPT
4131 * this is the entry point to schedule() from in-kernel preemption
4132 * off of preempt_enable. Kernel preemptions off return from interrupt
4133 * occur there and call schedule directly.
4135 asmlinkage
void __sched
preempt_schedule(void)
4137 struct thread_info
*ti
= current_thread_info();
4138 struct task_struct
*task
= current
;
4139 int saved_lock_depth
;
4142 * If there is a non-zero preempt_count or interrupts are disabled,
4143 * we do not want to preempt the current task. Just return..
4145 if (likely(ti
->preempt_count
|| irqs_disabled()))
4149 add_preempt_count(PREEMPT_ACTIVE
);
4152 * We keep the big kernel semaphore locked, but we
4153 * clear ->lock_depth so that schedule() doesnt
4154 * auto-release the semaphore:
4156 saved_lock_depth
= task
->lock_depth
;
4157 task
->lock_depth
= -1;
4159 task
->lock_depth
= saved_lock_depth
;
4160 sub_preempt_count(PREEMPT_ACTIVE
);
4163 * Check again in case we missed a preemption opportunity
4164 * between schedule and now.
4167 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4169 EXPORT_SYMBOL(preempt_schedule
);
4172 * this is the entry point to schedule() from kernel preemption
4173 * off of irq context.
4174 * Note, that this is called and return with irqs disabled. This will
4175 * protect us against recursive calling from irq.
4177 asmlinkage
void __sched
preempt_schedule_irq(void)
4179 struct thread_info
*ti
= current_thread_info();
4180 struct task_struct
*task
= current
;
4181 int saved_lock_depth
;
4183 /* Catch callers which need to be fixed */
4184 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4187 add_preempt_count(PREEMPT_ACTIVE
);
4190 * We keep the big kernel semaphore locked, but we
4191 * clear ->lock_depth so that schedule() doesnt
4192 * auto-release the semaphore:
4194 saved_lock_depth
= task
->lock_depth
;
4195 task
->lock_depth
= -1;
4198 local_irq_disable();
4199 task
->lock_depth
= saved_lock_depth
;
4200 sub_preempt_count(PREEMPT_ACTIVE
);
4203 * Check again in case we missed a preemption opportunity
4204 * between schedule and now.
4207 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4210 #endif /* CONFIG_PREEMPT */
4212 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4215 return try_to_wake_up(curr
->private, mode
, sync
);
4217 EXPORT_SYMBOL(default_wake_function
);
4220 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4221 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4222 * number) then we wake all the non-exclusive tasks and one exclusive task.
4224 * There are circumstances in which we can try to wake a task which has already
4225 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4226 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4228 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4229 int nr_exclusive
, int sync
, void *key
)
4231 wait_queue_t
*curr
, *next
;
4233 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4234 unsigned flags
= curr
->flags
;
4236 if (curr
->func(curr
, mode
, sync
, key
) &&
4237 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4243 * __wake_up - wake up threads blocked on a waitqueue.
4245 * @mode: which threads
4246 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4247 * @key: is directly passed to the wakeup function
4249 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4250 int nr_exclusive
, void *key
)
4252 unsigned long flags
;
4254 spin_lock_irqsave(&q
->lock
, flags
);
4255 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4256 spin_unlock_irqrestore(&q
->lock
, flags
);
4258 EXPORT_SYMBOL(__wake_up
);
4261 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4263 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4265 __wake_up_common(q
, mode
, 1, 0, NULL
);
4269 * __wake_up_sync - wake up threads blocked on a waitqueue.
4271 * @mode: which threads
4272 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4274 * The sync wakeup differs that the waker knows that it will schedule
4275 * away soon, so while the target thread will be woken up, it will not
4276 * be migrated to another CPU - ie. the two threads are 'synchronized'
4277 * with each other. This can prevent needless bouncing between CPUs.
4279 * On UP it can prevent extra preemption.
4282 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4284 unsigned long flags
;
4290 if (unlikely(!nr_exclusive
))
4293 spin_lock_irqsave(&q
->lock
, flags
);
4294 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4295 spin_unlock_irqrestore(&q
->lock
, flags
);
4297 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4299 void complete(struct completion
*x
)
4301 unsigned long flags
;
4303 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4305 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4306 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4308 EXPORT_SYMBOL(complete
);
4310 void complete_all(struct completion
*x
)
4312 unsigned long flags
;
4314 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4315 x
->done
+= UINT_MAX
/2;
4316 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4317 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4319 EXPORT_SYMBOL(complete_all
);
4321 static inline long __sched
4322 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4325 DECLARE_WAITQUEUE(wait
, current
);
4327 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4328 __add_wait_queue_tail(&x
->wait
, &wait
);
4330 if ((state
== TASK_INTERRUPTIBLE
&&
4331 signal_pending(current
)) ||
4332 (state
== TASK_KILLABLE
&&
4333 fatal_signal_pending(current
))) {
4334 __remove_wait_queue(&x
->wait
, &wait
);
4335 return -ERESTARTSYS
;
4337 __set_current_state(state
);
4338 spin_unlock_irq(&x
->wait
.lock
);
4339 timeout
= schedule_timeout(timeout
);
4340 spin_lock_irq(&x
->wait
.lock
);
4342 __remove_wait_queue(&x
->wait
, &wait
);
4346 __remove_wait_queue(&x
->wait
, &wait
);
4353 wait_for_common(struct completion
*x
, long timeout
, int state
)
4357 spin_lock_irq(&x
->wait
.lock
);
4358 timeout
= do_wait_for_common(x
, timeout
, state
);
4359 spin_unlock_irq(&x
->wait
.lock
);
4363 void __sched
wait_for_completion(struct completion
*x
)
4365 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4367 EXPORT_SYMBOL(wait_for_completion
);
4369 unsigned long __sched
4370 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4372 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4374 EXPORT_SYMBOL(wait_for_completion_timeout
);
4376 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4378 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4379 if (t
== -ERESTARTSYS
)
4383 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4385 unsigned long __sched
4386 wait_for_completion_interruptible_timeout(struct completion
*x
,
4387 unsigned long timeout
)
4389 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4391 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4393 int __sched
wait_for_completion_killable(struct completion
*x
)
4395 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4396 if (t
== -ERESTARTSYS
)
4400 EXPORT_SYMBOL(wait_for_completion_killable
);
4403 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4405 unsigned long flags
;
4408 init_waitqueue_entry(&wait
, current
);
4410 __set_current_state(state
);
4412 spin_lock_irqsave(&q
->lock
, flags
);
4413 __add_wait_queue(q
, &wait
);
4414 spin_unlock(&q
->lock
);
4415 timeout
= schedule_timeout(timeout
);
4416 spin_lock_irq(&q
->lock
);
4417 __remove_wait_queue(q
, &wait
);
4418 spin_unlock_irqrestore(&q
->lock
, flags
);
4423 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4425 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4427 EXPORT_SYMBOL(interruptible_sleep_on
);
4430 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4432 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4434 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4436 void __sched
sleep_on(wait_queue_head_t
*q
)
4438 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4440 EXPORT_SYMBOL(sleep_on
);
4442 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4444 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4446 EXPORT_SYMBOL(sleep_on_timeout
);
4448 #ifdef CONFIG_RT_MUTEXES
4451 * rt_mutex_setprio - set the current priority of a task
4453 * @prio: prio value (kernel-internal form)
4455 * This function changes the 'effective' priority of a task. It does
4456 * not touch ->normal_prio like __setscheduler().
4458 * Used by the rt_mutex code to implement priority inheritance logic.
4460 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4462 unsigned long flags
;
4463 int oldprio
, on_rq
, running
;
4465 const struct sched_class
*prev_class
= p
->sched_class
;
4467 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4469 rq
= task_rq_lock(p
, &flags
);
4470 update_rq_clock(rq
);
4473 on_rq
= p
->se
.on_rq
;
4474 running
= task_current(rq
, p
);
4476 dequeue_task(rq
, p
, 0);
4478 p
->sched_class
->put_prev_task(rq
, p
);
4481 p
->sched_class
= &rt_sched_class
;
4483 p
->sched_class
= &fair_sched_class
;
4488 p
->sched_class
->set_curr_task(rq
);
4490 enqueue_task(rq
, p
, 0);
4492 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4494 task_rq_unlock(rq
, &flags
);
4499 void set_user_nice(struct task_struct
*p
, long nice
)
4501 int old_prio
, delta
, on_rq
;
4502 unsigned long flags
;
4505 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4508 * We have to be careful, if called from sys_setpriority(),
4509 * the task might be in the middle of scheduling on another CPU.
4511 rq
= task_rq_lock(p
, &flags
);
4512 update_rq_clock(rq
);
4514 * The RT priorities are set via sched_setscheduler(), but we still
4515 * allow the 'normal' nice value to be set - but as expected
4516 * it wont have any effect on scheduling until the task is
4517 * SCHED_FIFO/SCHED_RR:
4519 if (task_has_rt_policy(p
)) {
4520 p
->static_prio
= NICE_TO_PRIO(nice
);
4523 on_rq
= p
->se
.on_rq
;
4525 dequeue_task(rq
, p
, 0);
4529 p
->static_prio
= NICE_TO_PRIO(nice
);
4532 p
->prio
= effective_prio(p
);
4533 delta
= p
->prio
- old_prio
;
4536 enqueue_task(rq
, p
, 0);
4539 * If the task increased its priority or is running and
4540 * lowered its priority, then reschedule its CPU:
4542 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4543 resched_task(rq
->curr
);
4546 task_rq_unlock(rq
, &flags
);
4548 EXPORT_SYMBOL(set_user_nice
);
4551 * can_nice - check if a task can reduce its nice value
4555 int can_nice(const struct task_struct
*p
, const int nice
)
4557 /* convert nice value [19,-20] to rlimit style value [1,40] */
4558 int nice_rlim
= 20 - nice
;
4560 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
4561 capable(CAP_SYS_NICE
));
4564 #ifdef __ARCH_WANT_SYS_NICE
4567 * sys_nice - change the priority of the current process.
4568 * @increment: priority increment
4570 * sys_setpriority is a more generic, but much slower function that
4571 * does similar things.
4573 asmlinkage
long sys_nice(int increment
)
4578 * Setpriority might change our priority at the same moment.
4579 * We don't have to worry. Conceptually one call occurs first
4580 * and we have a single winner.
4582 if (increment
< -40)
4587 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
4593 if (increment
< 0 && !can_nice(current
, nice
))
4596 retval
= security_task_setnice(current
, nice
);
4600 set_user_nice(current
, nice
);
4607 * task_prio - return the priority value of a given task.
4608 * @p: the task in question.
4610 * This is the priority value as seen by users in /proc.
4611 * RT tasks are offset by -200. Normal tasks are centered
4612 * around 0, value goes from -16 to +15.
4614 int task_prio(const struct task_struct
*p
)
4616 return p
->prio
- MAX_RT_PRIO
;
4620 * task_nice - return the nice value of a given task.
4621 * @p: the task in question.
4623 int task_nice(const struct task_struct
*p
)
4625 return TASK_NICE(p
);
4627 EXPORT_SYMBOL(task_nice
);
4630 * idle_cpu - is a given cpu idle currently?
4631 * @cpu: the processor in question.
4633 int idle_cpu(int cpu
)
4635 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4639 * idle_task - return the idle task for a given cpu.
4640 * @cpu: the processor in question.
4642 struct task_struct
*idle_task(int cpu
)
4644 return cpu_rq(cpu
)->idle
;
4648 * find_process_by_pid - find a process with a matching PID value.
4649 * @pid: the pid in question.
4651 static struct task_struct
*find_process_by_pid(pid_t pid
)
4653 return pid
? find_task_by_vpid(pid
) : current
;
4656 /* Actually do priority change: must hold rq lock. */
4658 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4660 BUG_ON(p
->se
.on_rq
);
4663 switch (p
->policy
) {
4667 p
->sched_class
= &fair_sched_class
;
4671 p
->sched_class
= &rt_sched_class
;
4675 p
->rt_priority
= prio
;
4676 p
->normal_prio
= normal_prio(p
);
4677 /* we are holding p->pi_lock already */
4678 p
->prio
= rt_mutex_getprio(p
);
4683 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4684 * @p: the task in question.
4685 * @policy: new policy.
4686 * @param: structure containing the new RT priority.
4688 * NOTE that the task may be already dead.
4690 int sched_setscheduler(struct task_struct
*p
, int policy
,
4691 struct sched_param
*param
)
4693 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4694 unsigned long flags
;
4695 const struct sched_class
*prev_class
= p
->sched_class
;
4698 /* may grab non-irq protected spin_locks */
4699 BUG_ON(in_interrupt());
4701 /* double check policy once rq lock held */
4703 policy
= oldpolicy
= p
->policy
;
4704 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4705 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4706 policy
!= SCHED_IDLE
)
4709 * Valid priorities for SCHED_FIFO and SCHED_RR are
4710 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4711 * SCHED_BATCH and SCHED_IDLE is 0.
4713 if (param
->sched_priority
< 0 ||
4714 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4715 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4717 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4721 * Allow unprivileged RT tasks to decrease priority:
4723 if (!capable(CAP_SYS_NICE
)) {
4724 if (rt_policy(policy
)) {
4725 unsigned long rlim_rtprio
;
4727 if (!lock_task_sighand(p
, &flags
))
4729 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
4730 unlock_task_sighand(p
, &flags
);
4732 /* can't set/change the rt policy */
4733 if (policy
!= p
->policy
&& !rlim_rtprio
)
4736 /* can't increase priority */
4737 if (param
->sched_priority
> p
->rt_priority
&&
4738 param
->sched_priority
> rlim_rtprio
)
4742 * Like positive nice levels, dont allow tasks to
4743 * move out of SCHED_IDLE either:
4745 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4748 /* can't change other user's priorities */
4749 if ((current
->euid
!= p
->euid
) &&
4750 (current
->euid
!= p
->uid
))
4754 #ifdef CONFIG_RT_GROUP_SCHED
4756 * Do not allow realtime tasks into groups that have no runtime
4759 if (rt_policy(policy
) && task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
4763 retval
= security_task_setscheduler(p
, policy
, param
);
4767 * make sure no PI-waiters arrive (or leave) while we are
4768 * changing the priority of the task:
4770 spin_lock_irqsave(&p
->pi_lock
, flags
);
4772 * To be able to change p->policy safely, the apropriate
4773 * runqueue lock must be held.
4775 rq
= __task_rq_lock(p
);
4776 /* recheck policy now with rq lock held */
4777 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4778 policy
= oldpolicy
= -1;
4779 __task_rq_unlock(rq
);
4780 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4783 update_rq_clock(rq
);
4784 on_rq
= p
->se
.on_rq
;
4785 running
= task_current(rq
, p
);
4787 deactivate_task(rq
, p
, 0);
4789 p
->sched_class
->put_prev_task(rq
, p
);
4792 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4795 p
->sched_class
->set_curr_task(rq
);
4797 activate_task(rq
, p
, 0);
4799 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4801 __task_rq_unlock(rq
);
4802 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4804 rt_mutex_adjust_pi(p
);
4808 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4811 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4813 struct sched_param lparam
;
4814 struct task_struct
*p
;
4817 if (!param
|| pid
< 0)
4819 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4824 p
= find_process_by_pid(pid
);
4826 retval
= sched_setscheduler(p
, policy
, &lparam
);
4833 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4834 * @pid: the pid in question.
4835 * @policy: new policy.
4836 * @param: structure containing the new RT priority.
4839 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4841 /* negative values for policy are not valid */
4845 return do_sched_setscheduler(pid
, policy
, param
);
4849 * sys_sched_setparam - set/change the RT priority of a thread
4850 * @pid: the pid in question.
4851 * @param: structure containing the new RT priority.
4853 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
4855 return do_sched_setscheduler(pid
, -1, param
);
4859 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4860 * @pid: the pid in question.
4862 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
4864 struct task_struct
*p
;
4871 read_lock(&tasklist_lock
);
4872 p
= find_process_by_pid(pid
);
4874 retval
= security_task_getscheduler(p
);
4878 read_unlock(&tasklist_lock
);
4883 * sys_sched_getscheduler - get the RT priority of a thread
4884 * @pid: the pid in question.
4885 * @param: structure containing the RT priority.
4887 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
4889 struct sched_param lp
;
4890 struct task_struct
*p
;
4893 if (!param
|| pid
< 0)
4896 read_lock(&tasklist_lock
);
4897 p
= find_process_by_pid(pid
);
4902 retval
= security_task_getscheduler(p
);
4906 lp
.sched_priority
= p
->rt_priority
;
4907 read_unlock(&tasklist_lock
);
4910 * This one might sleep, we cannot do it with a spinlock held ...
4912 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4917 read_unlock(&tasklist_lock
);
4921 long sched_setaffinity(pid_t pid
, cpumask_t new_mask
)
4923 cpumask_t cpus_allowed
;
4924 struct task_struct
*p
;
4928 read_lock(&tasklist_lock
);
4930 p
= find_process_by_pid(pid
);
4932 read_unlock(&tasklist_lock
);
4938 * It is not safe to call set_cpus_allowed with the
4939 * tasklist_lock held. We will bump the task_struct's
4940 * usage count and then drop tasklist_lock.
4943 read_unlock(&tasklist_lock
);
4946 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
4947 !capable(CAP_SYS_NICE
))
4950 retval
= security_task_setscheduler(p
, 0, NULL
);
4954 cpus_allowed
= cpuset_cpus_allowed(p
);
4955 cpus_and(new_mask
, new_mask
, cpus_allowed
);
4957 retval
= set_cpus_allowed(p
, new_mask
);
4960 cpus_allowed
= cpuset_cpus_allowed(p
);
4961 if (!cpus_subset(new_mask
, cpus_allowed
)) {
4963 * We must have raced with a concurrent cpuset
4964 * update. Just reset the cpus_allowed to the
4965 * cpuset's cpus_allowed
4967 new_mask
= cpus_allowed
;
4977 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4978 cpumask_t
*new_mask
)
4980 if (len
< sizeof(cpumask_t
)) {
4981 memset(new_mask
, 0, sizeof(cpumask_t
));
4982 } else if (len
> sizeof(cpumask_t
)) {
4983 len
= sizeof(cpumask_t
);
4985 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4989 * sys_sched_setaffinity - set the cpu affinity of a process
4990 * @pid: pid of the process
4991 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4992 * @user_mask_ptr: user-space pointer to the new cpu mask
4994 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
4995 unsigned long __user
*user_mask_ptr
)
5000 retval
= get_user_cpu_mask(user_mask_ptr
, len
, &new_mask
);
5004 return sched_setaffinity(pid
, new_mask
);
5008 * Represents all cpu's present in the system
5009 * In systems capable of hotplug, this map could dynamically grow
5010 * as new cpu's are detected in the system via any platform specific
5011 * method, such as ACPI for e.g.
5014 cpumask_t cpu_present_map __read_mostly
;
5015 EXPORT_SYMBOL(cpu_present_map
);
5018 cpumask_t cpu_online_map __read_mostly
= CPU_MASK_ALL
;
5019 EXPORT_SYMBOL(cpu_online_map
);
5021 cpumask_t cpu_possible_map __read_mostly
= CPU_MASK_ALL
;
5022 EXPORT_SYMBOL(cpu_possible_map
);
5025 long sched_getaffinity(pid_t pid
, cpumask_t
*mask
)
5027 struct task_struct
*p
;
5031 read_lock(&tasklist_lock
);
5034 p
= find_process_by_pid(pid
);
5038 retval
= security_task_getscheduler(p
);
5042 cpus_and(*mask
, p
->cpus_allowed
, cpu_online_map
);
5045 read_unlock(&tasklist_lock
);
5052 * sys_sched_getaffinity - get the cpu affinity of a process
5053 * @pid: pid of the process
5054 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5055 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5057 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5058 unsigned long __user
*user_mask_ptr
)
5063 if (len
< sizeof(cpumask_t
))
5066 ret
= sched_getaffinity(pid
, &mask
);
5070 if (copy_to_user(user_mask_ptr
, &mask
, sizeof(cpumask_t
)))
5073 return sizeof(cpumask_t
);
5077 * sys_sched_yield - yield the current processor to other threads.
5079 * This function yields the current CPU to other tasks. If there are no
5080 * other threads running on this CPU then this function will return.
5082 asmlinkage
long sys_sched_yield(void)
5084 struct rq
*rq
= this_rq_lock();
5086 schedstat_inc(rq
, yld_count
);
5087 current
->sched_class
->yield_task(rq
);
5090 * Since we are going to call schedule() anyway, there's
5091 * no need to preempt or enable interrupts:
5093 __release(rq
->lock
);
5094 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5095 _raw_spin_unlock(&rq
->lock
);
5096 preempt_enable_no_resched();
5103 static void __cond_resched(void)
5105 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5106 __might_sleep(__FILE__
, __LINE__
);
5109 * The BKS might be reacquired before we have dropped
5110 * PREEMPT_ACTIVE, which could trigger a second
5111 * cond_resched() call.
5114 add_preempt_count(PREEMPT_ACTIVE
);
5116 sub_preempt_count(PREEMPT_ACTIVE
);
5117 } while (need_resched());
5120 #if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY)
5121 int __sched
_cond_resched(void)
5123 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5124 system_state
== SYSTEM_RUNNING
) {
5130 EXPORT_SYMBOL(_cond_resched
);
5134 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5135 * call schedule, and on return reacquire the lock.
5137 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5138 * operations here to prevent schedule() from being called twice (once via
5139 * spin_unlock(), once by hand).
5141 int cond_resched_lock(spinlock_t
*lock
)
5143 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5146 if (spin_needbreak(lock
) || resched
) {
5148 if (resched
&& need_resched())
5157 EXPORT_SYMBOL(cond_resched_lock
);
5159 int __sched
cond_resched_softirq(void)
5161 BUG_ON(!in_softirq());
5163 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5171 EXPORT_SYMBOL(cond_resched_softirq
);
5174 * yield - yield the current processor to other threads.
5176 * This is a shortcut for kernel-space yielding - it marks the
5177 * thread runnable and calls sys_sched_yield().
5179 void __sched
yield(void)
5181 set_current_state(TASK_RUNNING
);
5184 EXPORT_SYMBOL(yield
);
5187 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5188 * that process accounting knows that this is a task in IO wait state.
5190 * But don't do that if it is a deliberate, throttling IO wait (this task
5191 * has set its backing_dev_info: the queue against which it should throttle)
5193 void __sched
io_schedule(void)
5195 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5197 delayacct_blkio_start();
5198 atomic_inc(&rq
->nr_iowait
);
5200 atomic_dec(&rq
->nr_iowait
);
5201 delayacct_blkio_end();
5203 EXPORT_SYMBOL(io_schedule
);
5205 long __sched
io_schedule_timeout(long timeout
)
5207 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5210 delayacct_blkio_start();
5211 atomic_inc(&rq
->nr_iowait
);
5212 ret
= schedule_timeout(timeout
);
5213 atomic_dec(&rq
->nr_iowait
);
5214 delayacct_blkio_end();
5219 * sys_sched_get_priority_max - return maximum RT priority.
5220 * @policy: scheduling class.
5222 * this syscall returns the maximum rt_priority that can be used
5223 * by a given scheduling class.
5225 asmlinkage
long sys_sched_get_priority_max(int policy
)
5232 ret
= MAX_USER_RT_PRIO
-1;
5244 * sys_sched_get_priority_min - return minimum RT priority.
5245 * @policy: scheduling class.
5247 * this syscall returns the minimum rt_priority that can be used
5248 * by a given scheduling class.
5250 asmlinkage
long sys_sched_get_priority_min(int policy
)
5268 * sys_sched_rr_get_interval - return the default timeslice of a process.
5269 * @pid: pid of the process.
5270 * @interval: userspace pointer to the timeslice value.
5272 * this syscall writes the default timeslice value of a given process
5273 * into the user-space timespec buffer. A value of '0' means infinity.
5276 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5278 struct task_struct
*p
;
5279 unsigned int time_slice
;
5287 read_lock(&tasklist_lock
);
5288 p
= find_process_by_pid(pid
);
5292 retval
= security_task_getscheduler(p
);
5297 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5298 * tasks that are on an otherwise idle runqueue:
5301 if (p
->policy
== SCHED_RR
) {
5302 time_slice
= DEF_TIMESLICE
;
5303 } else if (p
->policy
!= SCHED_FIFO
) {
5304 struct sched_entity
*se
= &p
->se
;
5305 unsigned long flags
;
5308 rq
= task_rq_lock(p
, &flags
);
5309 if (rq
->cfs
.load
.weight
)
5310 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5311 task_rq_unlock(rq
, &flags
);
5313 read_unlock(&tasklist_lock
);
5314 jiffies_to_timespec(time_slice
, &t
);
5315 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5319 read_unlock(&tasklist_lock
);
5323 static const char stat_nam
[] = "RSDTtZX";
5325 void sched_show_task(struct task_struct
*p
)
5327 unsigned long free
= 0;
5330 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5331 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5332 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5333 #if BITS_PER_LONG == 32
5334 if (state
== TASK_RUNNING
)
5335 printk(KERN_CONT
" running ");
5337 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5339 if (state
== TASK_RUNNING
)
5340 printk(KERN_CONT
" running task ");
5342 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5344 #ifdef CONFIG_DEBUG_STACK_USAGE
5346 unsigned long *n
= end_of_stack(p
);
5349 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
5352 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
5353 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
5355 show_stack(p
, NULL
);
5358 void show_state_filter(unsigned long state_filter
)
5360 struct task_struct
*g
, *p
;
5362 #if BITS_PER_LONG == 32
5364 " task PC stack pid father\n");
5367 " task PC stack pid father\n");
5369 read_lock(&tasklist_lock
);
5370 do_each_thread(g
, p
) {
5372 * reset the NMI-timeout, listing all files on a slow
5373 * console might take alot of time:
5375 touch_nmi_watchdog();
5376 if (!state_filter
|| (p
->state
& state_filter
))
5378 } while_each_thread(g
, p
);
5380 touch_all_softlockup_watchdogs();
5382 #ifdef CONFIG_SCHED_DEBUG
5383 sysrq_sched_debug_show();
5385 read_unlock(&tasklist_lock
);
5387 * Only show locks if all tasks are dumped:
5389 if (state_filter
== -1)
5390 debug_show_all_locks();
5393 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5395 idle
->sched_class
= &idle_sched_class
;
5399 * init_idle - set up an idle thread for a given CPU
5400 * @idle: task in question
5401 * @cpu: cpu the idle task belongs to
5403 * NOTE: this function does not set the idle thread's NEED_RESCHED
5404 * flag, to make booting more robust.
5406 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5408 struct rq
*rq
= cpu_rq(cpu
);
5409 unsigned long flags
;
5412 idle
->se
.exec_start
= sched_clock();
5414 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
5415 idle
->cpus_allowed
= cpumask_of_cpu(cpu
);
5416 __set_task_cpu(idle
, cpu
);
5418 spin_lock_irqsave(&rq
->lock
, flags
);
5419 rq
->curr
= rq
->idle
= idle
;
5420 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5423 spin_unlock_irqrestore(&rq
->lock
, flags
);
5425 /* Set the preempt count _outside_ the spinlocks! */
5426 task_thread_info(idle
)->preempt_count
= 0;
5429 * The idle tasks have their own, simple scheduling class:
5431 idle
->sched_class
= &idle_sched_class
;
5435 * In a system that switches off the HZ timer nohz_cpu_mask
5436 * indicates which cpus entered this state. This is used
5437 * in the rcu update to wait only for active cpus. For system
5438 * which do not switch off the HZ timer nohz_cpu_mask should
5439 * always be CPU_MASK_NONE.
5441 cpumask_t nohz_cpu_mask
= CPU_MASK_NONE
;
5444 * Increase the granularity value when there are more CPUs,
5445 * because with more CPUs the 'effective latency' as visible
5446 * to users decreases. But the relationship is not linear,
5447 * so pick a second-best guess by going with the log2 of the
5450 * This idea comes from the SD scheduler of Con Kolivas:
5452 static inline void sched_init_granularity(void)
5454 unsigned int factor
= 1 + ilog2(num_online_cpus());
5455 const unsigned long limit
= 200000000;
5457 sysctl_sched_min_granularity
*= factor
;
5458 if (sysctl_sched_min_granularity
> limit
)
5459 sysctl_sched_min_granularity
= limit
;
5461 sysctl_sched_latency
*= factor
;
5462 if (sysctl_sched_latency
> limit
)
5463 sysctl_sched_latency
= limit
;
5465 sysctl_sched_wakeup_granularity
*= factor
;
5470 * This is how migration works:
5472 * 1) we queue a struct migration_req structure in the source CPU's
5473 * runqueue and wake up that CPU's migration thread.
5474 * 2) we down() the locked semaphore => thread blocks.
5475 * 3) migration thread wakes up (implicitly it forces the migrated
5476 * thread off the CPU)
5477 * 4) it gets the migration request and checks whether the migrated
5478 * task is still in the wrong runqueue.
5479 * 5) if it's in the wrong runqueue then the migration thread removes
5480 * it and puts it into the right queue.
5481 * 6) migration thread up()s the semaphore.
5482 * 7) we wake up and the migration is done.
5486 * Change a given task's CPU affinity. Migrate the thread to a
5487 * proper CPU and schedule it away if the CPU it's executing on
5488 * is removed from the allowed bitmask.
5490 * NOTE: the caller must have a valid reference to the task, the
5491 * task must not exit() & deallocate itself prematurely. The
5492 * call is not atomic; no spinlocks may be held.
5494 int set_cpus_allowed(struct task_struct
*p
, cpumask_t new_mask
)
5496 struct migration_req req
;
5497 unsigned long flags
;
5501 rq
= task_rq_lock(p
, &flags
);
5502 if (!cpus_intersects(new_mask
, cpu_online_map
)) {
5507 if (p
->sched_class
->set_cpus_allowed
)
5508 p
->sched_class
->set_cpus_allowed(p
, &new_mask
);
5510 p
->cpus_allowed
= new_mask
;
5511 p
->rt
.nr_cpus_allowed
= cpus_weight(new_mask
);
5514 /* Can the task run on the task's current CPU? If so, we're done */
5515 if (cpu_isset(task_cpu(p
), new_mask
))
5518 if (migrate_task(p
, any_online_cpu(new_mask
), &req
)) {
5519 /* Need help from migration thread: drop lock and wait. */
5520 task_rq_unlock(rq
, &flags
);
5521 wake_up_process(rq
->migration_thread
);
5522 wait_for_completion(&req
.done
);
5523 tlb_migrate_finish(p
->mm
);
5527 task_rq_unlock(rq
, &flags
);
5531 EXPORT_SYMBOL_GPL(set_cpus_allowed
);
5534 * Move (not current) task off this cpu, onto dest cpu. We're doing
5535 * this because either it can't run here any more (set_cpus_allowed()
5536 * away from this CPU, or CPU going down), or because we're
5537 * attempting to rebalance this task on exec (sched_exec).
5539 * So we race with normal scheduler movements, but that's OK, as long
5540 * as the task is no longer on this CPU.
5542 * Returns non-zero if task was successfully migrated.
5544 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5546 struct rq
*rq_dest
, *rq_src
;
5549 if (unlikely(cpu_is_offline(dest_cpu
)))
5552 rq_src
= cpu_rq(src_cpu
);
5553 rq_dest
= cpu_rq(dest_cpu
);
5555 double_rq_lock(rq_src
, rq_dest
);
5556 /* Already moved. */
5557 if (task_cpu(p
) != src_cpu
)
5559 /* Affinity changed (again). */
5560 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
))
5563 on_rq
= p
->se
.on_rq
;
5565 deactivate_task(rq_src
, p
, 0);
5567 set_task_cpu(p
, dest_cpu
);
5569 activate_task(rq_dest
, p
, 0);
5570 check_preempt_curr(rq_dest
, p
);
5574 double_rq_unlock(rq_src
, rq_dest
);
5579 * migration_thread - this is a highprio system thread that performs
5580 * thread migration by bumping thread off CPU then 'pushing' onto
5583 static int migration_thread(void *data
)
5585 int cpu
= (long)data
;
5589 BUG_ON(rq
->migration_thread
!= current
);
5591 set_current_state(TASK_INTERRUPTIBLE
);
5592 while (!kthread_should_stop()) {
5593 struct migration_req
*req
;
5594 struct list_head
*head
;
5596 spin_lock_irq(&rq
->lock
);
5598 if (cpu_is_offline(cpu
)) {
5599 spin_unlock_irq(&rq
->lock
);
5603 if (rq
->active_balance
) {
5604 active_load_balance(rq
, cpu
);
5605 rq
->active_balance
= 0;
5608 head
= &rq
->migration_queue
;
5610 if (list_empty(head
)) {
5611 spin_unlock_irq(&rq
->lock
);
5613 set_current_state(TASK_INTERRUPTIBLE
);
5616 req
= list_entry(head
->next
, struct migration_req
, list
);
5617 list_del_init(head
->next
);
5619 spin_unlock(&rq
->lock
);
5620 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
5623 complete(&req
->done
);
5625 __set_current_state(TASK_RUNNING
);
5629 /* Wait for kthread_stop */
5630 set_current_state(TASK_INTERRUPTIBLE
);
5631 while (!kthread_should_stop()) {
5633 set_current_state(TASK_INTERRUPTIBLE
);
5635 __set_current_state(TASK_RUNNING
);
5639 #ifdef CONFIG_HOTPLUG_CPU
5641 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5645 local_irq_disable();
5646 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
5652 * Figure out where task on dead CPU should go, use force if necessary.
5653 * NOTE: interrupts should be disabled by the caller
5655 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5657 unsigned long flags
;
5664 mask
= node_to_cpumask(cpu_to_node(dead_cpu
));
5665 cpus_and(mask
, mask
, p
->cpus_allowed
);
5666 dest_cpu
= any_online_cpu(mask
);
5668 /* On any allowed CPU? */
5669 if (dest_cpu
== NR_CPUS
)
5670 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5672 /* No more Mr. Nice Guy. */
5673 if (dest_cpu
== NR_CPUS
) {
5674 cpumask_t cpus_allowed
= cpuset_cpus_allowed_locked(p
);
5676 * Try to stay on the same cpuset, where the
5677 * current cpuset may be a subset of all cpus.
5678 * The cpuset_cpus_allowed_locked() variant of
5679 * cpuset_cpus_allowed() will not block. It must be
5680 * called within calls to cpuset_lock/cpuset_unlock.
5682 rq
= task_rq_lock(p
, &flags
);
5683 p
->cpus_allowed
= cpus_allowed
;
5684 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5685 task_rq_unlock(rq
, &flags
);
5688 * Don't tell them about moving exiting tasks or
5689 * kernel threads (both mm NULL), since they never
5692 if (p
->mm
&& printk_ratelimit()) {
5693 printk(KERN_INFO
"process %d (%s) no "
5694 "longer affine to cpu%d\n",
5695 task_pid_nr(p
), p
->comm
, dead_cpu
);
5698 } while (!__migrate_task_irq(p
, dead_cpu
, dest_cpu
));
5702 * While a dead CPU has no uninterruptible tasks queued at this point,
5703 * it might still have a nonzero ->nr_uninterruptible counter, because
5704 * for performance reasons the counter is not stricly tracking tasks to
5705 * their home CPUs. So we just add the counter to another CPU's counter,
5706 * to keep the global sum constant after CPU-down:
5708 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5710 struct rq
*rq_dest
= cpu_rq(any_online_cpu(CPU_MASK_ALL
));
5711 unsigned long flags
;
5713 local_irq_save(flags
);
5714 double_rq_lock(rq_src
, rq_dest
);
5715 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5716 rq_src
->nr_uninterruptible
= 0;
5717 double_rq_unlock(rq_src
, rq_dest
);
5718 local_irq_restore(flags
);
5721 /* Run through task list and migrate tasks from the dead cpu. */
5722 static void migrate_live_tasks(int src_cpu
)
5724 struct task_struct
*p
, *t
;
5726 read_lock(&tasklist_lock
);
5728 do_each_thread(t
, p
) {
5732 if (task_cpu(p
) == src_cpu
)
5733 move_task_off_dead_cpu(src_cpu
, p
);
5734 } while_each_thread(t
, p
);
5736 read_unlock(&tasklist_lock
);
5740 * Schedules idle task to be the next runnable task on current CPU.
5741 * It does so by boosting its priority to highest possible.
5742 * Used by CPU offline code.
5744 void sched_idle_next(void)
5746 int this_cpu
= smp_processor_id();
5747 struct rq
*rq
= cpu_rq(this_cpu
);
5748 struct task_struct
*p
= rq
->idle
;
5749 unsigned long flags
;
5751 /* cpu has to be offline */
5752 BUG_ON(cpu_online(this_cpu
));
5755 * Strictly not necessary since rest of the CPUs are stopped by now
5756 * and interrupts disabled on the current cpu.
5758 spin_lock_irqsave(&rq
->lock
, flags
);
5760 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5762 update_rq_clock(rq
);
5763 activate_task(rq
, p
, 0);
5765 spin_unlock_irqrestore(&rq
->lock
, flags
);
5769 * Ensures that the idle task is using init_mm right before its cpu goes
5772 void idle_task_exit(void)
5774 struct mm_struct
*mm
= current
->active_mm
;
5776 BUG_ON(cpu_online(smp_processor_id()));
5779 switch_mm(mm
, &init_mm
, current
);
5783 /* called under rq->lock with disabled interrupts */
5784 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5786 struct rq
*rq
= cpu_rq(dead_cpu
);
5788 /* Must be exiting, otherwise would be on tasklist. */
5789 BUG_ON(!p
->exit_state
);
5791 /* Cannot have done final schedule yet: would have vanished. */
5792 BUG_ON(p
->state
== TASK_DEAD
);
5797 * Drop lock around migration; if someone else moves it,
5798 * that's OK. No task can be added to this CPU, so iteration is
5801 spin_unlock_irq(&rq
->lock
);
5802 move_task_off_dead_cpu(dead_cpu
, p
);
5803 spin_lock_irq(&rq
->lock
);
5808 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5809 static void migrate_dead_tasks(unsigned int dead_cpu
)
5811 struct rq
*rq
= cpu_rq(dead_cpu
);
5812 struct task_struct
*next
;
5815 if (!rq
->nr_running
)
5817 update_rq_clock(rq
);
5818 next
= pick_next_task(rq
, rq
->curr
);
5821 migrate_dead(dead_cpu
, next
);
5825 #endif /* CONFIG_HOTPLUG_CPU */
5827 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5829 static struct ctl_table sd_ctl_dir
[] = {
5831 .procname
= "sched_domain",
5837 static struct ctl_table sd_ctl_root
[] = {
5839 .ctl_name
= CTL_KERN
,
5840 .procname
= "kernel",
5842 .child
= sd_ctl_dir
,
5847 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5849 struct ctl_table
*entry
=
5850 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5855 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5857 struct ctl_table
*entry
;
5860 * In the intermediate directories, both the child directory and
5861 * procname are dynamically allocated and could fail but the mode
5862 * will always be set. In the lowest directory the names are
5863 * static strings and all have proc handlers.
5865 for (entry
= *tablep
; entry
->mode
; entry
++) {
5867 sd_free_ctl_entry(&entry
->child
);
5868 if (entry
->proc_handler
== NULL
)
5869 kfree(entry
->procname
);
5877 set_table_entry(struct ctl_table
*entry
,
5878 const char *procname
, void *data
, int maxlen
,
5879 mode_t mode
, proc_handler
*proc_handler
)
5881 entry
->procname
= procname
;
5883 entry
->maxlen
= maxlen
;
5885 entry
->proc_handler
= proc_handler
;
5888 static struct ctl_table
*
5889 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5891 struct ctl_table
*table
= sd_alloc_ctl_entry(12);
5896 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5897 sizeof(long), 0644, proc_doulongvec_minmax
);
5898 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5899 sizeof(long), 0644, proc_doulongvec_minmax
);
5900 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5901 sizeof(int), 0644, proc_dointvec_minmax
);
5902 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5903 sizeof(int), 0644, proc_dointvec_minmax
);
5904 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5905 sizeof(int), 0644, proc_dointvec_minmax
);
5906 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5907 sizeof(int), 0644, proc_dointvec_minmax
);
5908 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5909 sizeof(int), 0644, proc_dointvec_minmax
);
5910 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5911 sizeof(int), 0644, proc_dointvec_minmax
);
5912 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5913 sizeof(int), 0644, proc_dointvec_minmax
);
5914 set_table_entry(&table
[9], "cache_nice_tries",
5915 &sd
->cache_nice_tries
,
5916 sizeof(int), 0644, proc_dointvec_minmax
);
5917 set_table_entry(&table
[10], "flags", &sd
->flags
,
5918 sizeof(int), 0644, proc_dointvec_minmax
);
5919 /* &table[11] is terminator */
5924 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5926 struct ctl_table
*entry
, *table
;
5927 struct sched_domain
*sd
;
5928 int domain_num
= 0, i
;
5931 for_each_domain(cpu
, sd
)
5933 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5938 for_each_domain(cpu
, sd
) {
5939 snprintf(buf
, 32, "domain%d", i
);
5940 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5942 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5949 static struct ctl_table_header
*sd_sysctl_header
;
5950 static void register_sched_domain_sysctl(void)
5952 int i
, cpu_num
= num_online_cpus();
5953 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5956 WARN_ON(sd_ctl_dir
[0].child
);
5957 sd_ctl_dir
[0].child
= entry
;
5962 for_each_online_cpu(i
) {
5963 snprintf(buf
, 32, "cpu%d", i
);
5964 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5966 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5970 WARN_ON(sd_sysctl_header
);
5971 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5974 /* may be called multiple times per register */
5975 static void unregister_sched_domain_sysctl(void)
5977 if (sd_sysctl_header
)
5978 unregister_sysctl_table(sd_sysctl_header
);
5979 sd_sysctl_header
= NULL
;
5980 if (sd_ctl_dir
[0].child
)
5981 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5984 static void register_sched_domain_sysctl(void)
5987 static void unregister_sched_domain_sysctl(void)
5993 * migration_call - callback that gets triggered when a CPU is added.
5994 * Here we can start up the necessary migration thread for the new CPU.
5996 static int __cpuinit
5997 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5999 struct task_struct
*p
;
6000 int cpu
= (long)hcpu
;
6001 unsigned long flags
;
6006 case CPU_UP_PREPARE
:
6007 case CPU_UP_PREPARE_FROZEN
:
6008 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6011 kthread_bind(p
, cpu
);
6012 /* Must be high prio: stop_machine expects to yield to it. */
6013 rq
= task_rq_lock(p
, &flags
);
6014 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6015 task_rq_unlock(rq
, &flags
);
6016 cpu_rq(cpu
)->migration_thread
= p
;
6020 case CPU_ONLINE_FROZEN
:
6021 /* Strictly unnecessary, as first user will wake it. */
6022 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6024 /* Update our root-domain */
6026 spin_lock_irqsave(&rq
->lock
, flags
);
6028 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6029 cpu_set(cpu
, rq
->rd
->online
);
6031 spin_unlock_irqrestore(&rq
->lock
, flags
);
6034 #ifdef CONFIG_HOTPLUG_CPU
6035 case CPU_UP_CANCELED
:
6036 case CPU_UP_CANCELED_FROZEN
:
6037 if (!cpu_rq(cpu
)->migration_thread
)
6039 /* Unbind it from offline cpu so it can run. Fall thru. */
6040 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6041 any_online_cpu(cpu_online_map
));
6042 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6043 cpu_rq(cpu
)->migration_thread
= NULL
;
6047 case CPU_DEAD_FROZEN
:
6048 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6049 migrate_live_tasks(cpu
);
6051 kthread_stop(rq
->migration_thread
);
6052 rq
->migration_thread
= NULL
;
6053 /* Idle task back to normal (off runqueue, low prio) */
6054 spin_lock_irq(&rq
->lock
);
6055 update_rq_clock(rq
);
6056 deactivate_task(rq
, rq
->idle
, 0);
6057 rq
->idle
->static_prio
= MAX_PRIO
;
6058 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6059 rq
->idle
->sched_class
= &idle_sched_class
;
6060 migrate_dead_tasks(cpu
);
6061 spin_unlock_irq(&rq
->lock
);
6063 migrate_nr_uninterruptible(rq
);
6064 BUG_ON(rq
->nr_running
!= 0);
6067 * No need to migrate the tasks: it was best-effort if
6068 * they didn't take sched_hotcpu_mutex. Just wake up
6071 spin_lock_irq(&rq
->lock
);
6072 while (!list_empty(&rq
->migration_queue
)) {
6073 struct migration_req
*req
;
6075 req
= list_entry(rq
->migration_queue
.next
,
6076 struct migration_req
, list
);
6077 list_del_init(&req
->list
);
6078 complete(&req
->done
);
6080 spin_unlock_irq(&rq
->lock
);
6084 case CPU_DYING_FROZEN
:
6085 /* Update our root-domain */
6087 spin_lock_irqsave(&rq
->lock
, flags
);
6089 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6090 cpu_clear(cpu
, rq
->rd
->online
);
6092 spin_unlock_irqrestore(&rq
->lock
, flags
);
6099 /* Register at highest priority so that task migration (migrate_all_tasks)
6100 * happens before everything else.
6102 static struct notifier_block __cpuinitdata migration_notifier
= {
6103 .notifier_call
= migration_call
,
6107 void __init
migration_init(void)
6109 void *cpu
= (void *)(long)smp_processor_id();
6112 /* Start one for the boot CPU: */
6113 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6114 BUG_ON(err
== NOTIFY_BAD
);
6115 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6116 register_cpu_notifier(&migration_notifier
);
6122 /* Number of possible processor ids */
6123 int nr_cpu_ids __read_mostly
= NR_CPUS
;
6124 EXPORT_SYMBOL(nr_cpu_ids
);
6126 #ifdef CONFIG_SCHED_DEBUG
6128 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
)
6130 struct sched_group
*group
= sd
->groups
;
6131 cpumask_t groupmask
;
6134 cpumask_scnprintf(str
, NR_CPUS
, sd
->span
);
6135 cpus_clear(groupmask
);
6137 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6139 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6140 printk("does not load-balance\n");
6142 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6147 printk(KERN_CONT
"span %s\n", str
);
6149 if (!cpu_isset(cpu
, sd
->span
)) {
6150 printk(KERN_ERR
"ERROR: domain->span does not contain "
6153 if (!cpu_isset(cpu
, group
->cpumask
)) {
6154 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6158 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6162 printk(KERN_ERR
"ERROR: group is NULL\n");
6166 if (!group
->__cpu_power
) {
6167 printk(KERN_CONT
"\n");
6168 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6173 if (!cpus_weight(group
->cpumask
)) {
6174 printk(KERN_CONT
"\n");
6175 printk(KERN_ERR
"ERROR: empty group\n");
6179 if (cpus_intersects(groupmask
, group
->cpumask
)) {
6180 printk(KERN_CONT
"\n");
6181 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6185 cpus_or(groupmask
, groupmask
, group
->cpumask
);
6187 cpumask_scnprintf(str
, NR_CPUS
, group
->cpumask
);
6188 printk(KERN_CONT
" %s", str
);
6190 group
= group
->next
;
6191 } while (group
!= sd
->groups
);
6192 printk(KERN_CONT
"\n");
6194 if (!cpus_equal(sd
->span
, groupmask
))
6195 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6197 if (sd
->parent
&& !cpus_subset(groupmask
, sd
->parent
->span
))
6198 printk(KERN_ERR
"ERROR: parent span is not a superset "
6199 "of domain->span\n");
6203 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6208 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6212 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6215 if (sched_domain_debug_one(sd
, cpu
, level
))
6224 # define sched_domain_debug(sd, cpu) do { } while (0)
6227 static int sd_degenerate(struct sched_domain
*sd
)
6229 if (cpus_weight(sd
->span
) == 1)
6232 /* Following flags need at least 2 groups */
6233 if (sd
->flags
& (SD_LOAD_BALANCE
|
6234 SD_BALANCE_NEWIDLE
|
6238 SD_SHARE_PKG_RESOURCES
)) {
6239 if (sd
->groups
!= sd
->groups
->next
)
6243 /* Following flags don't use groups */
6244 if (sd
->flags
& (SD_WAKE_IDLE
|
6253 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6255 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6257 if (sd_degenerate(parent
))
6260 if (!cpus_equal(sd
->span
, parent
->span
))
6263 /* Does parent contain flags not in child? */
6264 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6265 if (cflags
& SD_WAKE_AFFINE
)
6266 pflags
&= ~SD_WAKE_BALANCE
;
6267 /* Flags needing groups don't count if only 1 group in parent */
6268 if (parent
->groups
== parent
->groups
->next
) {
6269 pflags
&= ~(SD_LOAD_BALANCE
|
6270 SD_BALANCE_NEWIDLE
|
6274 SD_SHARE_PKG_RESOURCES
);
6276 if (~cflags
& pflags
)
6282 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6284 unsigned long flags
;
6285 const struct sched_class
*class;
6287 spin_lock_irqsave(&rq
->lock
, flags
);
6290 struct root_domain
*old_rd
= rq
->rd
;
6292 for (class = sched_class_highest
; class; class = class->next
) {
6293 if (class->leave_domain
)
6294 class->leave_domain(rq
);
6297 cpu_clear(rq
->cpu
, old_rd
->span
);
6298 cpu_clear(rq
->cpu
, old_rd
->online
);
6300 if (atomic_dec_and_test(&old_rd
->refcount
))
6304 atomic_inc(&rd
->refcount
);
6307 cpu_set(rq
->cpu
, rd
->span
);
6308 if (cpu_isset(rq
->cpu
, cpu_online_map
))
6309 cpu_set(rq
->cpu
, rd
->online
);
6311 for (class = sched_class_highest
; class; class = class->next
) {
6312 if (class->join_domain
)
6313 class->join_domain(rq
);
6316 spin_unlock_irqrestore(&rq
->lock
, flags
);
6319 static void init_rootdomain(struct root_domain
*rd
)
6321 memset(rd
, 0, sizeof(*rd
));
6323 cpus_clear(rd
->span
);
6324 cpus_clear(rd
->online
);
6327 static void init_defrootdomain(void)
6329 init_rootdomain(&def_root_domain
);
6330 atomic_set(&def_root_domain
.refcount
, 1);
6333 static struct root_domain
*alloc_rootdomain(void)
6335 struct root_domain
*rd
;
6337 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6341 init_rootdomain(rd
);
6347 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6348 * hold the hotplug lock.
6351 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6353 struct rq
*rq
= cpu_rq(cpu
);
6354 struct sched_domain
*tmp
;
6356 /* Remove the sched domains which do not contribute to scheduling. */
6357 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
) {
6358 struct sched_domain
*parent
= tmp
->parent
;
6361 if (sd_parent_degenerate(tmp
, parent
)) {
6362 tmp
->parent
= parent
->parent
;
6364 parent
->parent
->child
= tmp
;
6368 if (sd
&& sd_degenerate(sd
)) {
6374 sched_domain_debug(sd
, cpu
);
6376 rq_attach_root(rq
, rd
);
6377 rcu_assign_pointer(rq
->sd
, sd
);
6380 /* cpus with isolated domains */
6381 static cpumask_t cpu_isolated_map
= CPU_MASK_NONE
;
6383 /* Setup the mask of cpus configured for isolated domains */
6384 static int __init
isolated_cpu_setup(char *str
)
6386 int ints
[NR_CPUS
], i
;
6388 str
= get_options(str
, ARRAY_SIZE(ints
), ints
);
6389 cpus_clear(cpu_isolated_map
);
6390 for (i
= 1; i
<= ints
[0]; i
++)
6391 if (ints
[i
] < NR_CPUS
)
6392 cpu_set(ints
[i
], cpu_isolated_map
);
6396 __setup("isolcpus=", isolated_cpu_setup
);
6399 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6400 * to a function which identifies what group(along with sched group) a CPU
6401 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6402 * (due to the fact that we keep track of groups covered with a cpumask_t).
6404 * init_sched_build_groups will build a circular linked list of the groups
6405 * covered by the given span, and will set each group's ->cpumask correctly,
6406 * and ->cpu_power to 0.
6409 init_sched_build_groups(cpumask_t span
, const cpumask_t
*cpu_map
,
6410 int (*group_fn
)(int cpu
, const cpumask_t
*cpu_map
,
6411 struct sched_group
**sg
))
6413 struct sched_group
*first
= NULL
, *last
= NULL
;
6414 cpumask_t covered
= CPU_MASK_NONE
;
6417 for_each_cpu_mask(i
, span
) {
6418 struct sched_group
*sg
;
6419 int group
= group_fn(i
, cpu_map
, &sg
);
6422 if (cpu_isset(i
, covered
))
6425 sg
->cpumask
= CPU_MASK_NONE
;
6426 sg
->__cpu_power
= 0;
6428 for_each_cpu_mask(j
, span
) {
6429 if (group_fn(j
, cpu_map
, NULL
) != group
)
6432 cpu_set(j
, covered
);
6433 cpu_set(j
, sg
->cpumask
);
6444 #define SD_NODES_PER_DOMAIN 16
6449 * find_next_best_node - find the next node to include in a sched_domain
6450 * @node: node whose sched_domain we're building
6451 * @used_nodes: nodes already in the sched_domain
6453 * Find the next node to include in a given scheduling domain. Simply
6454 * finds the closest node not already in the @used_nodes map.
6456 * Should use nodemask_t.
6458 static int find_next_best_node(int node
, unsigned long *used_nodes
)
6460 int i
, n
, val
, min_val
, best_node
= 0;
6464 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6465 /* Start at @node */
6466 n
= (node
+ i
) % MAX_NUMNODES
;
6468 if (!nr_cpus_node(n
))
6471 /* Skip already used nodes */
6472 if (test_bit(n
, used_nodes
))
6475 /* Simple min distance search */
6476 val
= node_distance(node
, n
);
6478 if (val
< min_val
) {
6484 set_bit(best_node
, used_nodes
);
6489 * sched_domain_node_span - get a cpumask for a node's sched_domain
6490 * @node: node whose cpumask we're constructing
6491 * @size: number of nodes to include in this span
6493 * Given a node, construct a good cpumask for its sched_domain to span. It
6494 * should be one that prevents unnecessary balancing, but also spreads tasks
6497 static cpumask_t
sched_domain_node_span(int node
)
6499 DECLARE_BITMAP(used_nodes
, MAX_NUMNODES
);
6500 cpumask_t span
, nodemask
;
6504 bitmap_zero(used_nodes
, MAX_NUMNODES
);
6506 nodemask
= node_to_cpumask(node
);
6507 cpus_or(span
, span
, nodemask
);
6508 set_bit(node
, used_nodes
);
6510 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6511 int next_node
= find_next_best_node(node
, used_nodes
);
6513 nodemask
= node_to_cpumask(next_node
);
6514 cpus_or(span
, span
, nodemask
);
6521 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6524 * SMT sched-domains:
6526 #ifdef CONFIG_SCHED_SMT
6527 static DEFINE_PER_CPU(struct sched_domain
, cpu_domains
);
6528 static DEFINE_PER_CPU(struct sched_group
, sched_group_cpus
);
6531 cpu_to_cpu_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
)
6534 *sg
= &per_cpu(sched_group_cpus
, cpu
);
6540 * multi-core sched-domains:
6542 #ifdef CONFIG_SCHED_MC
6543 static DEFINE_PER_CPU(struct sched_domain
, core_domains
);
6544 static DEFINE_PER_CPU(struct sched_group
, sched_group_core
);
6547 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6549 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
)
6552 cpumask_t mask
= per_cpu(cpu_sibling_map
, cpu
);
6553 cpus_and(mask
, mask
, *cpu_map
);
6554 group
= first_cpu(mask
);
6556 *sg
= &per_cpu(sched_group_core
, group
);
6559 #elif defined(CONFIG_SCHED_MC)
6561 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
)
6564 *sg
= &per_cpu(sched_group_core
, cpu
);
6569 static DEFINE_PER_CPU(struct sched_domain
, phys_domains
);
6570 static DEFINE_PER_CPU(struct sched_group
, sched_group_phys
);
6573 cpu_to_phys_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
)
6576 #ifdef CONFIG_SCHED_MC
6577 cpumask_t mask
= cpu_coregroup_map(cpu
);
6578 cpus_and(mask
, mask
, *cpu_map
);
6579 group
= first_cpu(mask
);
6580 #elif defined(CONFIG_SCHED_SMT)
6581 cpumask_t mask
= per_cpu(cpu_sibling_map
, cpu
);
6582 cpus_and(mask
, mask
, *cpu_map
);
6583 group
= first_cpu(mask
);
6588 *sg
= &per_cpu(sched_group_phys
, group
);
6594 * The init_sched_build_groups can't handle what we want to do with node
6595 * groups, so roll our own. Now each node has its own list of groups which
6596 * gets dynamically allocated.
6598 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
6599 static struct sched_group
**sched_group_nodes_bycpu
[NR_CPUS
];
6601 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
6602 static DEFINE_PER_CPU(struct sched_group
, sched_group_allnodes
);
6604 static int cpu_to_allnodes_group(int cpu
, const cpumask_t
*cpu_map
,
6605 struct sched_group
**sg
)
6607 cpumask_t nodemask
= node_to_cpumask(cpu_to_node(cpu
));
6610 cpus_and(nodemask
, nodemask
, *cpu_map
);
6611 group
= first_cpu(nodemask
);
6614 *sg
= &per_cpu(sched_group_allnodes
, group
);
6618 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6620 struct sched_group
*sg
= group_head
;
6626 for_each_cpu_mask(j
, sg
->cpumask
) {
6627 struct sched_domain
*sd
;
6629 sd
= &per_cpu(phys_domains
, j
);
6630 if (j
!= first_cpu(sd
->groups
->cpumask
)) {
6632 * Only add "power" once for each
6638 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
6641 } while (sg
!= group_head
);
6646 /* Free memory allocated for various sched_group structures */
6647 static void free_sched_groups(const cpumask_t
*cpu_map
)
6651 for_each_cpu_mask(cpu
, *cpu_map
) {
6652 struct sched_group
**sched_group_nodes
6653 = sched_group_nodes_bycpu
[cpu
];
6655 if (!sched_group_nodes
)
6658 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6659 cpumask_t nodemask
= node_to_cpumask(i
);
6660 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6662 cpus_and(nodemask
, nodemask
, *cpu_map
);
6663 if (cpus_empty(nodemask
))
6673 if (oldsg
!= sched_group_nodes
[i
])
6676 kfree(sched_group_nodes
);
6677 sched_group_nodes_bycpu
[cpu
] = NULL
;
6681 static void free_sched_groups(const cpumask_t
*cpu_map
)
6687 * Initialize sched groups cpu_power.
6689 * cpu_power indicates the capacity of sched group, which is used while
6690 * distributing the load between different sched groups in a sched domain.
6691 * Typically cpu_power for all the groups in a sched domain will be same unless
6692 * there are asymmetries in the topology. If there are asymmetries, group
6693 * having more cpu_power will pickup more load compared to the group having
6696 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6697 * the maximum number of tasks a group can handle in the presence of other idle
6698 * or lightly loaded groups in the same sched domain.
6700 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6702 struct sched_domain
*child
;
6703 struct sched_group
*group
;
6705 WARN_ON(!sd
|| !sd
->groups
);
6707 if (cpu
!= first_cpu(sd
->groups
->cpumask
))
6712 sd
->groups
->__cpu_power
= 0;
6715 * For perf policy, if the groups in child domain share resources
6716 * (for example cores sharing some portions of the cache hierarchy
6717 * or SMT), then set this domain groups cpu_power such that each group
6718 * can handle only one task, when there are other idle groups in the
6719 * same sched domain.
6721 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
6723 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
6724 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
6729 * add cpu_power of each child group to this groups cpu_power
6731 group
= child
->groups
;
6733 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
6734 group
= group
->next
;
6735 } while (group
!= child
->groups
);
6739 * Build sched domains for a given set of cpus and attach the sched domains
6740 * to the individual cpus
6742 static int build_sched_domains(const cpumask_t
*cpu_map
)
6745 struct root_domain
*rd
;
6747 struct sched_group
**sched_group_nodes
= NULL
;
6748 int sd_allnodes
= 0;
6751 * Allocate the per-node list of sched groups
6753 sched_group_nodes
= kcalloc(MAX_NUMNODES
, sizeof(struct sched_group
*),
6755 if (!sched_group_nodes
) {
6756 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6759 sched_group_nodes_bycpu
[first_cpu(*cpu_map
)] = sched_group_nodes
;
6762 rd
= alloc_rootdomain();
6764 printk(KERN_WARNING
"Cannot alloc root domain\n");
6769 * Set up domains for cpus specified by the cpu_map.
6771 for_each_cpu_mask(i
, *cpu_map
) {
6772 struct sched_domain
*sd
= NULL
, *p
;
6773 cpumask_t nodemask
= node_to_cpumask(cpu_to_node(i
));
6775 cpus_and(nodemask
, nodemask
, *cpu_map
);
6778 if (cpus_weight(*cpu_map
) >
6779 SD_NODES_PER_DOMAIN
*cpus_weight(nodemask
)) {
6780 sd
= &per_cpu(allnodes_domains
, i
);
6781 *sd
= SD_ALLNODES_INIT
;
6782 sd
->span
= *cpu_map
;
6783 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
);
6789 sd
= &per_cpu(node_domains
, i
);
6791 sd
->span
= sched_domain_node_span(cpu_to_node(i
));
6795 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6799 sd
= &per_cpu(phys_domains
, i
);
6801 sd
->span
= nodemask
;
6805 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
);
6807 #ifdef CONFIG_SCHED_MC
6809 sd
= &per_cpu(core_domains
, i
);
6811 sd
->span
= cpu_coregroup_map(i
);
6812 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6815 cpu_to_core_group(i
, cpu_map
, &sd
->groups
);
6818 #ifdef CONFIG_SCHED_SMT
6820 sd
= &per_cpu(cpu_domains
, i
);
6821 *sd
= SD_SIBLING_INIT
;
6822 sd
->span
= per_cpu(cpu_sibling_map
, i
);
6823 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6826 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
);
6830 #ifdef CONFIG_SCHED_SMT
6831 /* Set up CPU (sibling) groups */
6832 for_each_cpu_mask(i
, *cpu_map
) {
6833 cpumask_t this_sibling_map
= per_cpu(cpu_sibling_map
, i
);
6834 cpus_and(this_sibling_map
, this_sibling_map
, *cpu_map
);
6835 if (i
!= first_cpu(this_sibling_map
))
6838 init_sched_build_groups(this_sibling_map
, cpu_map
,
6843 #ifdef CONFIG_SCHED_MC
6844 /* Set up multi-core groups */
6845 for_each_cpu_mask(i
, *cpu_map
) {
6846 cpumask_t this_core_map
= cpu_coregroup_map(i
);
6847 cpus_and(this_core_map
, this_core_map
, *cpu_map
);
6848 if (i
!= first_cpu(this_core_map
))
6850 init_sched_build_groups(this_core_map
, cpu_map
,
6851 &cpu_to_core_group
);
6855 /* Set up physical groups */
6856 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6857 cpumask_t nodemask
= node_to_cpumask(i
);
6859 cpus_and(nodemask
, nodemask
, *cpu_map
);
6860 if (cpus_empty(nodemask
))
6863 init_sched_build_groups(nodemask
, cpu_map
, &cpu_to_phys_group
);
6867 /* Set up node groups */
6869 init_sched_build_groups(*cpu_map
, cpu_map
,
6870 &cpu_to_allnodes_group
);
6872 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6873 /* Set up node groups */
6874 struct sched_group
*sg
, *prev
;
6875 cpumask_t nodemask
= node_to_cpumask(i
);
6876 cpumask_t domainspan
;
6877 cpumask_t covered
= CPU_MASK_NONE
;
6880 cpus_and(nodemask
, nodemask
, *cpu_map
);
6881 if (cpus_empty(nodemask
)) {
6882 sched_group_nodes
[i
] = NULL
;
6886 domainspan
= sched_domain_node_span(i
);
6887 cpus_and(domainspan
, domainspan
, *cpu_map
);
6889 sg
= kmalloc_node(sizeof(struct sched_group
), GFP_KERNEL
, i
);
6891 printk(KERN_WARNING
"Can not alloc domain group for "
6895 sched_group_nodes
[i
] = sg
;
6896 for_each_cpu_mask(j
, nodemask
) {
6897 struct sched_domain
*sd
;
6899 sd
= &per_cpu(node_domains
, j
);
6902 sg
->__cpu_power
= 0;
6903 sg
->cpumask
= nodemask
;
6905 cpus_or(covered
, covered
, nodemask
);
6908 for (j
= 0; j
< MAX_NUMNODES
; j
++) {
6909 cpumask_t tmp
, notcovered
;
6910 int n
= (i
+ j
) % MAX_NUMNODES
;
6912 cpus_complement(notcovered
, covered
);
6913 cpus_and(tmp
, notcovered
, *cpu_map
);
6914 cpus_and(tmp
, tmp
, domainspan
);
6915 if (cpus_empty(tmp
))
6918 nodemask
= node_to_cpumask(n
);
6919 cpus_and(tmp
, tmp
, nodemask
);
6920 if (cpus_empty(tmp
))
6923 sg
= kmalloc_node(sizeof(struct sched_group
),
6927 "Can not alloc domain group for node %d\n", j
);
6930 sg
->__cpu_power
= 0;
6932 sg
->next
= prev
->next
;
6933 cpus_or(covered
, covered
, tmp
);
6940 /* Calculate CPU power for physical packages and nodes */
6941 #ifdef CONFIG_SCHED_SMT
6942 for_each_cpu_mask(i
, *cpu_map
) {
6943 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
);
6945 init_sched_groups_power(i
, sd
);
6948 #ifdef CONFIG_SCHED_MC
6949 for_each_cpu_mask(i
, *cpu_map
) {
6950 struct sched_domain
*sd
= &per_cpu(core_domains
, i
);
6952 init_sched_groups_power(i
, sd
);
6956 for_each_cpu_mask(i
, *cpu_map
) {
6957 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
);
6959 init_sched_groups_power(i
, sd
);
6963 for (i
= 0; i
< MAX_NUMNODES
; i
++)
6964 init_numa_sched_groups_power(sched_group_nodes
[i
]);
6967 struct sched_group
*sg
;
6969 cpu_to_allnodes_group(first_cpu(*cpu_map
), cpu_map
, &sg
);
6970 init_numa_sched_groups_power(sg
);
6974 /* Attach the domains */
6975 for_each_cpu_mask(i
, *cpu_map
) {
6976 struct sched_domain
*sd
;
6977 #ifdef CONFIG_SCHED_SMT
6978 sd
= &per_cpu(cpu_domains
, i
);
6979 #elif defined(CONFIG_SCHED_MC)
6980 sd
= &per_cpu(core_domains
, i
);
6982 sd
= &per_cpu(phys_domains
, i
);
6984 cpu_attach_domain(sd
, rd
, i
);
6991 free_sched_groups(cpu_map
);
6996 static cpumask_t
*doms_cur
; /* current sched domains */
6997 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7000 * Special case: If a kmalloc of a doms_cur partition (array of
7001 * cpumask_t) fails, then fallback to a single sched domain,
7002 * as determined by the single cpumask_t fallback_doms.
7004 static cpumask_t fallback_doms
;
7006 void __attribute__((weak
)) arch_update_cpu_topology(void)
7011 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7012 * For now this just excludes isolated cpus, but could be used to
7013 * exclude other special cases in the future.
7015 static int arch_init_sched_domains(const cpumask_t
*cpu_map
)
7019 arch_update_cpu_topology();
7021 doms_cur
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
7023 doms_cur
= &fallback_doms
;
7024 cpus_andnot(*doms_cur
, *cpu_map
, cpu_isolated_map
);
7025 err
= build_sched_domains(doms_cur
);
7026 register_sched_domain_sysctl();
7031 static void arch_destroy_sched_domains(const cpumask_t
*cpu_map
)
7033 free_sched_groups(cpu_map
);
7037 * Detach sched domains from a group of cpus specified in cpu_map
7038 * These cpus will now be attached to the NULL domain
7040 static void detach_destroy_domains(const cpumask_t
*cpu_map
)
7044 unregister_sched_domain_sysctl();
7046 for_each_cpu_mask(i
, *cpu_map
)
7047 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7048 synchronize_sched();
7049 arch_destroy_sched_domains(cpu_map
);
7053 * Partition sched domains as specified by the 'ndoms_new'
7054 * cpumasks in the array doms_new[] of cpumasks. This compares
7055 * doms_new[] to the current sched domain partitioning, doms_cur[].
7056 * It destroys each deleted domain and builds each new domain.
7058 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7059 * The masks don't intersect (don't overlap.) We should setup one
7060 * sched domain for each mask. CPUs not in any of the cpumasks will
7061 * not be load balanced. If the same cpumask appears both in the
7062 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7065 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7066 * ownership of it and will kfree it when done with it. If the caller
7067 * failed the kmalloc call, then it can pass in doms_new == NULL,
7068 * and partition_sched_domains() will fallback to the single partition
7071 * Call with hotplug lock held
7073 void partition_sched_domains(int ndoms_new
, cpumask_t
*doms_new
)
7079 /* always unregister in case we don't destroy any domains */
7080 unregister_sched_domain_sysctl();
7082 if (doms_new
== NULL
) {
7084 doms_new
= &fallback_doms
;
7085 cpus_andnot(doms_new
[0], cpu_online_map
, cpu_isolated_map
);
7088 /* Destroy deleted domains */
7089 for (i
= 0; i
< ndoms_cur
; i
++) {
7090 for (j
= 0; j
< ndoms_new
; j
++) {
7091 if (cpus_equal(doms_cur
[i
], doms_new
[j
]))
7094 /* no match - a current sched domain not in new doms_new[] */
7095 detach_destroy_domains(doms_cur
+ i
);
7100 /* Build new domains */
7101 for (i
= 0; i
< ndoms_new
; i
++) {
7102 for (j
= 0; j
< ndoms_cur
; j
++) {
7103 if (cpus_equal(doms_new
[i
], doms_cur
[j
]))
7106 /* no match - add a new doms_new */
7107 build_sched_domains(doms_new
+ i
);
7112 /* Remember the new sched domains */
7113 if (doms_cur
!= &fallback_doms
)
7115 doms_cur
= doms_new
;
7116 ndoms_cur
= ndoms_new
;
7118 register_sched_domain_sysctl();
7123 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7124 int arch_reinit_sched_domains(void)
7129 detach_destroy_domains(&cpu_online_map
);
7130 err
= arch_init_sched_domains(&cpu_online_map
);
7136 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7140 if (buf
[0] != '0' && buf
[0] != '1')
7144 sched_smt_power_savings
= (buf
[0] == '1');
7146 sched_mc_power_savings
= (buf
[0] == '1');
7148 ret
= arch_reinit_sched_domains();
7150 return ret
? ret
: count
;
7153 #ifdef CONFIG_SCHED_MC
7154 static ssize_t
sched_mc_power_savings_show(struct sys_device
*dev
, char *page
)
7156 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7158 static ssize_t
sched_mc_power_savings_store(struct sys_device
*dev
,
7159 const char *buf
, size_t count
)
7161 return sched_power_savings_store(buf
, count
, 0);
7163 static SYSDEV_ATTR(sched_mc_power_savings
, 0644, sched_mc_power_savings_show
,
7164 sched_mc_power_savings_store
);
7167 #ifdef CONFIG_SCHED_SMT
7168 static ssize_t
sched_smt_power_savings_show(struct sys_device
*dev
, char *page
)
7170 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7172 static ssize_t
sched_smt_power_savings_store(struct sys_device
*dev
,
7173 const char *buf
, size_t count
)
7175 return sched_power_savings_store(buf
, count
, 1);
7177 static SYSDEV_ATTR(sched_smt_power_savings
, 0644, sched_smt_power_savings_show
,
7178 sched_smt_power_savings_store
);
7181 int sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7185 #ifdef CONFIG_SCHED_SMT
7187 err
= sysfs_create_file(&cls
->kset
.kobj
,
7188 &attr_sched_smt_power_savings
.attr
);
7190 #ifdef CONFIG_SCHED_MC
7191 if (!err
&& mc_capable())
7192 err
= sysfs_create_file(&cls
->kset
.kobj
,
7193 &attr_sched_mc_power_savings
.attr
);
7200 * Force a reinitialization of the sched domains hierarchy. The domains
7201 * and groups cannot be updated in place without racing with the balancing
7202 * code, so we temporarily attach all running cpus to the NULL domain
7203 * which will prevent rebalancing while the sched domains are recalculated.
7205 static int update_sched_domains(struct notifier_block
*nfb
,
7206 unsigned long action
, void *hcpu
)
7209 case CPU_UP_PREPARE
:
7210 case CPU_UP_PREPARE_FROZEN
:
7211 case CPU_DOWN_PREPARE
:
7212 case CPU_DOWN_PREPARE_FROZEN
:
7213 detach_destroy_domains(&cpu_online_map
);
7216 case CPU_UP_CANCELED
:
7217 case CPU_UP_CANCELED_FROZEN
:
7218 case CPU_DOWN_FAILED
:
7219 case CPU_DOWN_FAILED_FROZEN
:
7221 case CPU_ONLINE_FROZEN
:
7223 case CPU_DEAD_FROZEN
:
7225 * Fall through and re-initialise the domains.
7232 /* The hotplug lock is already held by cpu_up/cpu_down */
7233 arch_init_sched_domains(&cpu_online_map
);
7238 void __init
sched_init_smp(void)
7240 cpumask_t non_isolated_cpus
;
7243 arch_init_sched_domains(&cpu_online_map
);
7244 cpus_andnot(non_isolated_cpus
, cpu_possible_map
, cpu_isolated_map
);
7245 if (cpus_empty(non_isolated_cpus
))
7246 cpu_set(smp_processor_id(), non_isolated_cpus
);
7248 /* XXX: Theoretical race here - CPU may be hotplugged now */
7249 hotcpu_notifier(update_sched_domains
, 0);
7251 /* Move init over to a non-isolated CPU */
7252 if (set_cpus_allowed(current
, non_isolated_cpus
) < 0)
7254 sched_init_granularity();
7257 void __init
sched_init_smp(void)
7259 sched_init_granularity();
7261 #endif /* CONFIG_SMP */
7263 int in_sched_functions(unsigned long addr
)
7265 return in_lock_functions(addr
) ||
7266 (addr
>= (unsigned long)__sched_text_start
7267 && addr
< (unsigned long)__sched_text_end
);
7270 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7272 cfs_rq
->tasks_timeline
= RB_ROOT
;
7273 #ifdef CONFIG_FAIR_GROUP_SCHED
7276 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7279 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7281 struct rt_prio_array
*array
;
7284 array
= &rt_rq
->active
;
7285 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7286 INIT_LIST_HEAD(array
->queue
+ i
);
7287 __clear_bit(i
, array
->bitmap
);
7289 /* delimiter for bitsearch: */
7290 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7292 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7293 rt_rq
->highest_prio
= MAX_RT_PRIO
;
7296 rt_rq
->rt_nr_migratory
= 0;
7297 rt_rq
->overloaded
= 0;
7301 rt_rq
->rt_throttled
= 0;
7303 #ifdef CONFIG_RT_GROUP_SCHED
7304 rt_rq
->rt_nr_boosted
= 0;
7309 #ifdef CONFIG_FAIR_GROUP_SCHED
7310 static void init_tg_cfs_entry(struct rq
*rq
, struct task_group
*tg
,
7311 struct cfs_rq
*cfs_rq
, struct sched_entity
*se
,
7314 tg
->cfs_rq
[cpu
] = cfs_rq
;
7315 init_cfs_rq(cfs_rq
, rq
);
7318 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7321 se
->cfs_rq
= &rq
->cfs
;
7323 se
->load
.weight
= tg
->shares
;
7324 se
->load
.inv_weight
= div64_64(1ULL<<32, se
->load
.weight
);
7329 #ifdef CONFIG_RT_GROUP_SCHED
7330 static void init_tg_rt_entry(struct rq
*rq
, struct task_group
*tg
,
7331 struct rt_rq
*rt_rq
, struct sched_rt_entity
*rt_se
,
7334 tg
->rt_rq
[cpu
] = rt_rq
;
7335 init_rt_rq(rt_rq
, rq
);
7337 rt_rq
->rt_se
= rt_se
;
7339 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7341 tg
->rt_se
[cpu
] = rt_se
;
7342 rt_se
->rt_rq
= &rq
->rt
;
7343 rt_se
->my_q
= rt_rq
;
7344 rt_se
->parent
= NULL
;
7345 INIT_LIST_HEAD(&rt_se
->run_list
);
7349 void __init
sched_init(void)
7351 int highest_cpu
= 0;
7355 init_defrootdomain();
7358 init_rt_bandwidth(&def_rt_bandwidth
,
7359 global_rt_period(), global_rt_runtime());
7361 #ifdef CONFIG_RT_GROUP_SCHED
7362 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7363 global_rt_period(), global_rt_runtime());
7366 #ifdef CONFIG_GROUP_SCHED
7367 list_add(&init_task_group
.list
, &task_groups
);
7370 for_each_possible_cpu(i
) {
7374 spin_lock_init(&rq
->lock
);
7375 lockdep_set_class(&rq
->lock
, &rq
->rq_lock_key
);
7378 update_last_tick_seen(rq
);
7379 init_cfs_rq(&rq
->cfs
, rq
);
7380 init_rt_rq(&rq
->rt
, rq
);
7381 #ifdef CONFIG_FAIR_GROUP_SCHED
7382 init_task_group
.shares
= init_task_group_load
;
7383 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7384 init_tg_cfs_entry(rq
, &init_task_group
,
7385 &per_cpu(init_cfs_rq
, i
),
7386 &per_cpu(init_sched_entity
, i
), i
, 1);
7389 #ifdef CONFIG_RT_GROUP_SCHED
7390 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7391 init_tg_rt_entry(rq
, &init_task_group
,
7392 &per_cpu(init_rt_rq
, i
),
7393 &per_cpu(init_sched_rt_entity
, i
), i
, 1);
7396 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7397 rq
->cpu_load
[j
] = 0;
7401 rq
->active_balance
= 0;
7402 rq
->next_balance
= jiffies
;
7405 rq
->migration_thread
= NULL
;
7406 INIT_LIST_HEAD(&rq
->migration_queue
);
7407 rq_attach_root(rq
, &def_root_domain
);
7410 atomic_set(&rq
->nr_iowait
, 0);
7414 set_load_weight(&init_task
);
7416 #ifdef CONFIG_PREEMPT_NOTIFIERS
7417 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7421 nr_cpu_ids
= highest_cpu
+ 1;
7422 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
, NULL
);
7425 #ifdef CONFIG_RT_MUTEXES
7426 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7430 * The boot idle thread does lazy MMU switching as well:
7432 atomic_inc(&init_mm
.mm_count
);
7433 enter_lazy_tlb(&init_mm
, current
);
7436 * Make us the idle thread. Technically, schedule() should not be
7437 * called from this thread, however somewhere below it might be,
7438 * but because we are the idle thread, we just pick up running again
7439 * when this runqueue becomes "idle".
7441 init_idle(current
, smp_processor_id());
7443 * During early bootup we pretend to be a normal task:
7445 current
->sched_class
= &fair_sched_class
;
7447 scheduler_running
= 1;
7450 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7451 void __might_sleep(char *file
, int line
)
7454 static unsigned long prev_jiffy
; /* ratelimiting */
7456 if ((in_atomic() || irqs_disabled()) &&
7457 system_state
== SYSTEM_RUNNING
&& !oops_in_progress
) {
7458 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7460 prev_jiffy
= jiffies
;
7461 printk(KERN_ERR
"BUG: sleeping function called from invalid"
7462 " context at %s:%d\n", file
, line
);
7463 printk("in_atomic():%d, irqs_disabled():%d\n",
7464 in_atomic(), irqs_disabled());
7465 debug_show_held_locks(current
);
7466 if (irqs_disabled())
7467 print_irqtrace_events(current
);
7472 EXPORT_SYMBOL(__might_sleep
);
7475 #ifdef CONFIG_MAGIC_SYSRQ
7476 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7479 update_rq_clock(rq
);
7480 on_rq
= p
->se
.on_rq
;
7482 deactivate_task(rq
, p
, 0);
7483 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7485 activate_task(rq
, p
, 0);
7486 resched_task(rq
->curr
);
7490 void normalize_rt_tasks(void)
7492 struct task_struct
*g
, *p
;
7493 unsigned long flags
;
7496 read_lock_irqsave(&tasklist_lock
, flags
);
7497 do_each_thread(g
, p
) {
7499 * Only normalize user tasks:
7504 p
->se
.exec_start
= 0;
7505 #ifdef CONFIG_SCHEDSTATS
7506 p
->se
.wait_start
= 0;
7507 p
->se
.sleep_start
= 0;
7508 p
->se
.block_start
= 0;
7510 task_rq(p
)->clock
= 0;
7514 * Renice negative nice level userspace
7517 if (TASK_NICE(p
) < 0 && p
->mm
)
7518 set_user_nice(p
, 0);
7522 spin_lock(&p
->pi_lock
);
7523 rq
= __task_rq_lock(p
);
7525 normalize_task(rq
, p
);
7527 __task_rq_unlock(rq
);
7528 spin_unlock(&p
->pi_lock
);
7529 } while_each_thread(g
, p
);
7531 read_unlock_irqrestore(&tasklist_lock
, flags
);
7534 #endif /* CONFIG_MAGIC_SYSRQ */
7538 * These functions are only useful for the IA64 MCA handling.
7540 * They can only be called when the whole system has been
7541 * stopped - every CPU needs to be quiescent, and no scheduling
7542 * activity can take place. Using them for anything else would
7543 * be a serious bug, and as a result, they aren't even visible
7544 * under any other configuration.
7548 * curr_task - return the current task for a given cpu.
7549 * @cpu: the processor in question.
7551 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7553 struct task_struct
*curr_task(int cpu
)
7555 return cpu_curr(cpu
);
7559 * set_curr_task - set the current task for a given cpu.
7560 * @cpu: the processor in question.
7561 * @p: the task pointer to set.
7563 * Description: This function must only be used when non-maskable interrupts
7564 * are serviced on a separate stack. It allows the architecture to switch the
7565 * notion of the current task on a cpu in a non-blocking manner. This function
7566 * must be called with all CPU's synchronized, and interrupts disabled, the
7567 * and caller must save the original value of the current task (see
7568 * curr_task() above) and restore that value before reenabling interrupts and
7569 * re-starting the system.
7571 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7573 void set_curr_task(int cpu
, struct task_struct
*p
)
7580 #ifdef CONFIG_FAIR_GROUP_SCHED
7581 static void free_fair_sched_group(struct task_group
*tg
)
7585 for_each_possible_cpu(i
) {
7587 kfree(tg
->cfs_rq
[i
]);
7596 static int alloc_fair_sched_group(struct task_group
*tg
)
7598 struct cfs_rq
*cfs_rq
;
7599 struct sched_entity
*se
;
7603 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * NR_CPUS
, GFP_KERNEL
);
7606 tg
->se
= kzalloc(sizeof(se
) * NR_CPUS
, GFP_KERNEL
);
7610 tg
->shares
= NICE_0_LOAD
;
7612 for_each_possible_cpu(i
) {
7615 cfs_rq
= kmalloc_node(sizeof(struct cfs_rq
),
7616 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7620 se
= kmalloc_node(sizeof(struct sched_entity
),
7621 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7625 init_tg_cfs_entry(rq
, tg
, cfs_rq
, se
, i
, 0);
7634 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7636 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
7637 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
7640 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
7642 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
7645 static inline void free_fair_sched_group(struct task_group
*tg
)
7649 static inline int alloc_fair_sched_group(struct task_group
*tg
)
7654 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7658 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
7663 #ifdef CONFIG_RT_GROUP_SCHED
7664 static void free_rt_sched_group(struct task_group
*tg
)
7668 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
7670 for_each_possible_cpu(i
) {
7672 kfree(tg
->rt_rq
[i
]);
7674 kfree(tg
->rt_se
[i
]);
7681 static int alloc_rt_sched_group(struct task_group
*tg
)
7683 struct rt_rq
*rt_rq
;
7684 struct sched_rt_entity
*rt_se
;
7688 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * NR_CPUS
, GFP_KERNEL
);
7691 tg
->rt_se
= kzalloc(sizeof(rt_se
) * NR_CPUS
, GFP_KERNEL
);
7695 init_rt_bandwidth(&tg
->rt_bandwidth
,
7696 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
7698 for_each_possible_cpu(i
) {
7701 rt_rq
= kmalloc_node(sizeof(struct rt_rq
),
7702 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7706 rt_se
= kmalloc_node(sizeof(struct sched_rt_entity
),
7707 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7711 init_tg_rt_entry(rq
, tg
, rt_rq
, rt_se
, i
, 0);
7720 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
7722 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
7723 &cpu_rq(cpu
)->leaf_rt_rq_list
);
7726 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
7728 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
7731 static inline void free_rt_sched_group(struct task_group
*tg
)
7735 static inline int alloc_rt_sched_group(struct task_group
*tg
)
7740 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
7744 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
7749 #ifdef CONFIG_GROUP_SCHED
7750 static void free_sched_group(struct task_group
*tg
)
7752 free_fair_sched_group(tg
);
7753 free_rt_sched_group(tg
);
7757 /* allocate runqueue etc for a new task group */
7758 struct task_group
*sched_create_group(void)
7760 struct task_group
*tg
;
7761 unsigned long flags
;
7764 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7766 return ERR_PTR(-ENOMEM
);
7768 if (!alloc_fair_sched_group(tg
))
7771 if (!alloc_rt_sched_group(tg
))
7774 spin_lock_irqsave(&task_group_lock
, flags
);
7775 for_each_possible_cpu(i
) {
7776 register_fair_sched_group(tg
, i
);
7777 register_rt_sched_group(tg
, i
);
7779 list_add_rcu(&tg
->list
, &task_groups
);
7780 spin_unlock_irqrestore(&task_group_lock
, flags
);
7785 free_sched_group(tg
);
7786 return ERR_PTR(-ENOMEM
);
7789 /* rcu callback to free various structures associated with a task group */
7790 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7792 /* now it should be safe to free those cfs_rqs */
7793 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7796 /* Destroy runqueue etc associated with a task group */
7797 void sched_destroy_group(struct task_group
*tg
)
7799 unsigned long flags
;
7802 spin_lock_irqsave(&task_group_lock
, flags
);
7803 for_each_possible_cpu(i
) {
7804 unregister_fair_sched_group(tg
, i
);
7805 unregister_rt_sched_group(tg
, i
);
7807 list_del_rcu(&tg
->list
);
7808 spin_unlock_irqrestore(&task_group_lock
, flags
);
7810 /* wait for possible concurrent references to cfs_rqs complete */
7811 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7814 /* change task's runqueue when it moves between groups.
7815 * The caller of this function should have put the task in its new group
7816 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7817 * reflect its new group.
7819 void sched_move_task(struct task_struct
*tsk
)
7822 unsigned long flags
;
7825 rq
= task_rq_lock(tsk
, &flags
);
7827 update_rq_clock(rq
);
7829 running
= task_current(rq
, tsk
);
7830 on_rq
= tsk
->se
.on_rq
;
7833 dequeue_task(rq
, tsk
, 0);
7834 if (unlikely(running
))
7835 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7837 set_task_rq(tsk
, task_cpu(tsk
));
7839 #ifdef CONFIG_FAIR_GROUP_SCHED
7840 if (tsk
->sched_class
->moved_group
)
7841 tsk
->sched_class
->moved_group(tsk
);
7844 if (unlikely(running
))
7845 tsk
->sched_class
->set_curr_task(rq
);
7847 enqueue_task(rq
, tsk
, 0);
7849 task_rq_unlock(rq
, &flags
);
7853 #ifdef CONFIG_FAIR_GROUP_SCHED
7854 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
7856 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
7857 struct rq
*rq
= cfs_rq
->rq
;
7860 spin_lock_irq(&rq
->lock
);
7864 dequeue_entity(cfs_rq
, se
, 0);
7866 se
->load
.weight
= shares
;
7867 se
->load
.inv_weight
= div64_64((1ULL<<32), shares
);
7870 enqueue_entity(cfs_rq
, se
, 0);
7872 spin_unlock_irq(&rq
->lock
);
7875 static DEFINE_MUTEX(shares_mutex
);
7877 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
7880 unsigned long flags
;
7883 * A weight of 0 or 1 can cause arithmetics problems.
7884 * (The default weight is 1024 - so there's no practical
7885 * limitation from this.)
7890 mutex_lock(&shares_mutex
);
7891 if (tg
->shares
== shares
)
7894 spin_lock_irqsave(&task_group_lock
, flags
);
7895 for_each_possible_cpu(i
)
7896 unregister_fair_sched_group(tg
, i
);
7897 spin_unlock_irqrestore(&task_group_lock
, flags
);
7899 /* wait for any ongoing reference to this group to finish */
7900 synchronize_sched();
7903 * Now we are free to modify the group's share on each cpu
7904 * w/o tripping rebalance_share or load_balance_fair.
7906 tg
->shares
= shares
;
7907 for_each_possible_cpu(i
)
7908 set_se_shares(tg
->se
[i
], shares
);
7911 * Enable load balance activity on this group, by inserting it back on
7912 * each cpu's rq->leaf_cfs_rq_list.
7914 spin_lock_irqsave(&task_group_lock
, flags
);
7915 for_each_possible_cpu(i
)
7916 register_fair_sched_group(tg
, i
);
7917 spin_unlock_irqrestore(&task_group_lock
, flags
);
7919 mutex_unlock(&shares_mutex
);
7923 unsigned long sched_group_shares(struct task_group
*tg
)
7929 #ifdef CONFIG_RT_GROUP_SCHED
7931 * Ensure that the real time constraints are schedulable.
7933 static DEFINE_MUTEX(rt_constraints_mutex
);
7935 static unsigned long to_ratio(u64 period
, u64 runtime
)
7937 if (runtime
== RUNTIME_INF
)
7940 return div64_64(runtime
<< 16, period
);
7943 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
7945 struct task_group
*tgi
;
7946 unsigned long total
= 0;
7947 unsigned long global_ratio
=
7948 to_ratio(global_rt_period(), global_rt_runtime());
7951 list_for_each_entry_rcu(tgi
, &task_groups
, list
) {
7955 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
7956 tgi
->rt_bandwidth
.rt_runtime
);
7960 return total
+ to_ratio(period
, runtime
) < global_ratio
;
7963 /* Must be called with tasklist_lock held */
7964 static inline int tg_has_rt_tasks(struct task_group
*tg
)
7966 struct task_struct
*g
, *p
;
7967 do_each_thread(g
, p
) {
7968 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
7970 } while_each_thread(g
, p
);
7974 static int tg_set_bandwidth(struct task_group
*tg
,
7975 u64 rt_period
, u64 rt_runtime
)
7979 mutex_lock(&rt_constraints_mutex
);
7980 read_lock(&tasklist_lock
);
7981 if (rt_runtime_us
== 0 && tg_has_rt_tasks(tg
)) {
7985 if (!__rt_schedulable(tg
, rt_period
, rt_runtime
)) {
7989 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
7990 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
7992 read_unlock(&tasklist_lock
);
7993 mutex_unlock(&rt_constraints_mutex
);
7998 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8000 u64 rt_runtime
, rt_period
;
8002 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8003 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8004 if (rt_runtime_us
< 0)
8005 rt_runtime
= RUNTIME_INF
;
8007 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8010 long sched_group_rt_runtime(struct task_group
*tg
)
8014 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8017 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8018 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8019 return rt_runtime_us
;
8022 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8024 u64 rt_runtime
, rt_period
;
8026 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8027 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8029 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8032 long sched_group_rt_period(struct task_group
*tg
)
8036 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8037 do_div(rt_period_us
, NSEC_PER_USEC
);
8038 return rt_period_us
;
8041 static int sched_rt_global_constraints(void)
8045 mutex_lock(&rt_constraints_mutex
);
8046 if (!__rt_schedulable(NULL
, 1, 0))
8048 mutex_unlock(&rt_constraints_mutex
);
8053 static int sched_rt_global_constraints(void)
8059 int sched_rt_handler(struct ctl_table
*table
, int write
,
8060 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
8064 int old_period
, old_runtime
;
8065 static DEFINE_MUTEX(mutex
);
8068 old_period
= sysctl_sched_rt_period
;
8069 old_runtime
= sysctl_sched_rt_runtime
;
8071 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
8073 if (!ret
&& write
) {
8074 ret
= sched_rt_global_constraints();
8076 sysctl_sched_rt_period
= old_period
;
8077 sysctl_sched_rt_runtime
= old_runtime
;
8079 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8080 def_rt_bandwidth
.rt_period
=
8081 ns_to_ktime(global_rt_period());
8084 mutex_unlock(&mutex
);
8089 #ifdef CONFIG_CGROUP_SCHED
8091 /* return corresponding task_group object of a cgroup */
8092 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8094 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8095 struct task_group
, css
);
8098 static struct cgroup_subsys_state
*
8099 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8101 struct task_group
*tg
;
8103 if (!cgrp
->parent
) {
8104 /* This is early initialization for the top cgroup */
8105 init_task_group
.css
.cgroup
= cgrp
;
8106 return &init_task_group
.css
;
8109 /* we support only 1-level deep hierarchical scheduler atm */
8110 if (cgrp
->parent
->parent
)
8111 return ERR_PTR(-EINVAL
);
8113 tg
= sched_create_group();
8115 return ERR_PTR(-ENOMEM
);
8117 /* Bind the cgroup to task_group object we just created */
8118 tg
->css
.cgroup
= cgrp
;
8124 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8126 struct task_group
*tg
= cgroup_tg(cgrp
);
8128 sched_destroy_group(tg
);
8132 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8133 struct task_struct
*tsk
)
8135 #ifdef CONFIG_RT_GROUP_SCHED
8136 /* Don't accept realtime tasks when there is no way for them to run */
8137 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
8140 /* We don't support RT-tasks being in separate groups */
8141 if (tsk
->sched_class
!= &fair_sched_class
)
8149 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8150 struct cgroup
*old_cont
, struct task_struct
*tsk
)
8152 sched_move_task(tsk
);
8155 #ifdef CONFIG_FAIR_GROUP_SCHED
8156 static int cpu_shares_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8159 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8162 static u64
cpu_shares_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8164 struct task_group
*tg
= cgroup_tg(cgrp
);
8166 return (u64
) tg
->shares
;
8170 #ifdef CONFIG_RT_GROUP_SCHED
8171 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8173 const char __user
*userbuf
,
8174 size_t nbytes
, loff_t
*unused_ppos
)
8183 if (nbytes
>= sizeof(buffer
))
8185 if (copy_from_user(buffer
, userbuf
, nbytes
))
8188 buffer
[nbytes
] = 0; /* nul-terminate */
8190 /* strip newline if necessary */
8191 if (nbytes
&& (buffer
[nbytes
-1] == '\n'))
8192 buffer
[nbytes
-1] = 0;
8193 val
= simple_strtoll(buffer
, &end
, 0);
8197 /* Pass to subsystem */
8198 retval
= sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8204 static ssize_t
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
,
8206 char __user
*buf
, size_t nbytes
,
8210 long val
= sched_group_rt_runtime(cgroup_tg(cgrp
));
8211 int len
= sprintf(tmp
, "%ld\n", val
);
8213 return simple_read_from_buffer(buf
, nbytes
, ppos
, tmp
, len
);
8216 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8219 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8222 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8224 return sched_group_rt_period(cgroup_tg(cgrp
));
8228 static struct cftype cpu_files
[] = {
8229 #ifdef CONFIG_FAIR_GROUP_SCHED
8232 .read_uint
= cpu_shares_read_uint
,
8233 .write_uint
= cpu_shares_write_uint
,
8236 #ifdef CONFIG_RT_GROUP_SCHED
8238 .name
= "rt_runtime_us",
8239 .read
= cpu_rt_runtime_read
,
8240 .write
= cpu_rt_runtime_write
,
8243 .name
= "rt_period_us",
8244 .read_uint
= cpu_rt_period_read_uint
,
8245 .write_uint
= cpu_rt_period_write_uint
,
8250 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8252 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8255 struct cgroup_subsys cpu_cgroup_subsys
= {
8257 .create
= cpu_cgroup_create
,
8258 .destroy
= cpu_cgroup_destroy
,
8259 .can_attach
= cpu_cgroup_can_attach
,
8260 .attach
= cpu_cgroup_attach
,
8261 .populate
= cpu_cgroup_populate
,
8262 .subsys_id
= cpu_cgroup_subsys_id
,
8266 #endif /* CONFIG_CGROUP_SCHED */
8268 #ifdef CONFIG_CGROUP_CPUACCT
8271 * CPU accounting code for task groups.
8273 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8274 * (balbir@in.ibm.com).
8277 /* track cpu usage of a group of tasks */
8279 struct cgroup_subsys_state css
;
8280 /* cpuusage holds pointer to a u64-type object on every cpu */
8284 struct cgroup_subsys cpuacct_subsys
;
8286 /* return cpu accounting group corresponding to this container */
8287 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cont
)
8289 return container_of(cgroup_subsys_state(cont
, cpuacct_subsys_id
),
8290 struct cpuacct
, css
);
8293 /* return cpu accounting group to which this task belongs */
8294 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8296 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8297 struct cpuacct
, css
);
8300 /* create a new cpu accounting group */
8301 static struct cgroup_subsys_state
*cpuacct_create(
8302 struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8304 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8307 return ERR_PTR(-ENOMEM
);
8309 ca
->cpuusage
= alloc_percpu(u64
);
8310 if (!ca
->cpuusage
) {
8312 return ERR_PTR(-ENOMEM
);
8318 /* destroy an existing cpu accounting group */
8320 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8322 struct cpuacct
*ca
= cgroup_ca(cont
);
8324 free_percpu(ca
->cpuusage
);
8328 /* return total cpu usage (in nanoseconds) of a group */
8329 static u64
cpuusage_read(struct cgroup
*cont
, struct cftype
*cft
)
8331 struct cpuacct
*ca
= cgroup_ca(cont
);
8332 u64 totalcpuusage
= 0;
8335 for_each_possible_cpu(i
) {
8336 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8339 * Take rq->lock to make 64-bit addition safe on 32-bit
8342 spin_lock_irq(&cpu_rq(i
)->lock
);
8343 totalcpuusage
+= *cpuusage
;
8344 spin_unlock_irq(&cpu_rq(i
)->lock
);
8347 return totalcpuusage
;
8350 static struct cftype files
[] = {
8353 .read_uint
= cpuusage_read
,
8357 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8359 return cgroup_add_files(cont
, ss
, files
, ARRAY_SIZE(files
));
8363 * charge this task's execution time to its accounting group.
8365 * called with rq->lock held.
8367 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8371 if (!cpuacct_subsys
.active
)
8376 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, task_cpu(tsk
));
8378 *cpuusage
+= cputime
;
8382 struct cgroup_subsys cpuacct_subsys
= {
8384 .create
= cpuacct_create
,
8385 .destroy
= cpuacct_destroy
,
8386 .populate
= cpuacct_populate
,
8387 .subsys_id
= cpuacct_subsys_id
,
8389 #endif /* CONFIG_CGROUP_CPUACCT */