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>
70 #include <linux/bootmem.h>
73 #include <asm/irq_regs.h>
76 * Scheduler clock - returns current time in nanosec units.
77 * This is default implementation.
78 * Architectures and sub-architectures can override this.
80 unsigned long long __attribute__((weak
)) sched_clock(void)
82 return (unsigned long long)jiffies
* (NSEC_PER_SEC
/ HZ
);
86 * Convert user-nice values [ -20 ... 0 ... 19 ]
87 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
90 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
91 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
92 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
95 * 'User priority' is the nice value converted to something we
96 * can work with better when scaling various scheduler parameters,
97 * it's a [ 0 ... 39 ] range.
99 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
100 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
101 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
104 * Helpers for converting nanosecond timing to jiffy resolution
106 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
108 #define NICE_0_LOAD SCHED_LOAD_SCALE
109 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
112 * These are the 'tuning knobs' of the scheduler:
114 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
115 * Timeslices get refilled after they expire.
117 #define DEF_TIMESLICE (100 * HZ / 1000)
120 * single value that denotes runtime == period, ie unlimited time.
122 #define RUNTIME_INF ((u64)~0ULL)
126 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
127 * Since cpu_power is a 'constant', we can use a reciprocal divide.
129 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
131 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
135 * Each time a sched group cpu_power is changed,
136 * we must compute its reciprocal value
138 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
140 sg
->__cpu_power
+= val
;
141 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
145 static inline int rt_policy(int policy
)
147 if (unlikely(policy
== SCHED_FIFO
) || unlikely(policy
== SCHED_RR
))
152 static inline int task_has_rt_policy(struct task_struct
*p
)
154 return rt_policy(p
->policy
);
158 * This is the priority-queue data structure of the RT scheduling class:
160 struct rt_prio_array
{
161 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
162 struct list_head queue
[MAX_RT_PRIO
];
165 struct rt_bandwidth
{
166 /* nests inside the rq lock: */
167 spinlock_t rt_runtime_lock
;
170 struct hrtimer rt_period_timer
;
173 static struct rt_bandwidth def_rt_bandwidth
;
175 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
177 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
179 struct rt_bandwidth
*rt_b
=
180 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
186 now
= hrtimer_cb_get_time(timer
);
187 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
192 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
195 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
199 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
201 rt_b
->rt_period
= ns_to_ktime(period
);
202 rt_b
->rt_runtime
= runtime
;
204 spin_lock_init(&rt_b
->rt_runtime_lock
);
206 hrtimer_init(&rt_b
->rt_period_timer
,
207 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
208 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
209 rt_b
->rt_period_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
212 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
216 if (rt_b
->rt_runtime
== RUNTIME_INF
)
219 if (hrtimer_active(&rt_b
->rt_period_timer
))
222 spin_lock(&rt_b
->rt_runtime_lock
);
224 if (hrtimer_active(&rt_b
->rt_period_timer
))
227 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
228 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
229 hrtimer_start(&rt_b
->rt_period_timer
,
230 rt_b
->rt_period_timer
.expires
,
233 spin_unlock(&rt_b
->rt_runtime_lock
);
236 #ifdef CONFIG_RT_GROUP_SCHED
237 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
239 hrtimer_cancel(&rt_b
->rt_period_timer
);
243 #ifdef CONFIG_GROUP_SCHED
245 #include <linux/cgroup.h>
249 static LIST_HEAD(task_groups
);
251 /* task group related information */
253 #ifdef CONFIG_CGROUP_SCHED
254 struct cgroup_subsys_state css
;
257 #ifdef CONFIG_FAIR_GROUP_SCHED
258 /* schedulable entities of this group on each cpu */
259 struct sched_entity
**se
;
260 /* runqueue "owned" by this group on each cpu */
261 struct cfs_rq
**cfs_rq
;
262 unsigned long shares
;
265 #ifdef CONFIG_RT_GROUP_SCHED
266 struct sched_rt_entity
**rt_se
;
267 struct rt_rq
**rt_rq
;
269 struct rt_bandwidth rt_bandwidth
;
273 struct list_head list
;
276 #ifdef CONFIG_USER_SCHED
280 * Every UID task group (including init_task_group aka UID-0) will
281 * be a child to this group.
283 struct task_group root_task_group
;
285 #ifdef CONFIG_FAIR_GROUP_SCHED
286 /* Default task group's sched entity on each cpu */
287 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
288 /* Default task group's cfs_rq on each cpu */
289 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
292 #ifdef CONFIG_RT_GROUP_SCHED
293 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
294 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
297 #define root_task_group init_task_group
300 /* task_group_lock serializes add/remove of task groups and also changes to
301 * a task group's cpu shares.
303 static DEFINE_SPINLOCK(task_group_lock
);
305 /* doms_cur_mutex serializes access to doms_cur[] array */
306 static DEFINE_MUTEX(doms_cur_mutex
);
308 #ifdef CONFIG_FAIR_GROUP_SCHED
309 #ifdef CONFIG_USER_SCHED
310 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
312 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
315 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
318 /* Default task group.
319 * Every task in system belong to this group at bootup.
321 struct task_group init_task_group
;
323 /* return group to which a task belongs */
324 static inline struct task_group
*task_group(struct task_struct
*p
)
326 struct task_group
*tg
;
328 #ifdef CONFIG_USER_SCHED
330 #elif defined(CONFIG_CGROUP_SCHED)
331 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
332 struct task_group
, css
);
334 tg
= &init_task_group
;
339 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
340 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
342 #ifdef CONFIG_FAIR_GROUP_SCHED
343 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
344 p
->se
.parent
= task_group(p
)->se
[cpu
];
347 #ifdef CONFIG_RT_GROUP_SCHED
348 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
349 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
353 static inline void lock_doms_cur(void)
355 mutex_lock(&doms_cur_mutex
);
358 static inline void unlock_doms_cur(void)
360 mutex_unlock(&doms_cur_mutex
);
365 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
366 static inline void lock_doms_cur(void) { }
367 static inline void unlock_doms_cur(void) { }
369 #endif /* CONFIG_GROUP_SCHED */
371 /* CFS-related fields in a runqueue */
373 struct load_weight load
;
374 unsigned long nr_running
;
379 struct rb_root tasks_timeline
;
380 struct rb_node
*rb_leftmost
;
381 struct rb_node
*rb_load_balance_curr
;
382 /* 'curr' points to currently running entity on this cfs_rq.
383 * It is set to NULL otherwise (i.e when none are currently running).
385 struct sched_entity
*curr
, *next
;
387 unsigned long nr_spread_over
;
389 #ifdef CONFIG_FAIR_GROUP_SCHED
390 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
393 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
394 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
395 * (like users, containers etc.)
397 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
398 * list is used during load balance.
400 struct list_head leaf_cfs_rq_list
;
401 struct task_group
*tg
; /* group that "owns" this runqueue */
405 /* Real-Time classes' related field in a runqueue: */
407 struct rt_prio_array active
;
408 unsigned long rt_nr_running
;
409 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
410 int highest_prio
; /* highest queued rt task prio */
413 unsigned long rt_nr_migratory
;
419 /* Nests inside the rq lock: */
420 spinlock_t rt_runtime_lock
;
422 #ifdef CONFIG_RT_GROUP_SCHED
423 unsigned long rt_nr_boosted
;
426 struct list_head leaf_rt_rq_list
;
427 struct task_group
*tg
;
428 struct sched_rt_entity
*rt_se
;
435 * We add the notion of a root-domain which will be used to define per-domain
436 * variables. Each exclusive cpuset essentially defines an island domain by
437 * fully partitioning the member cpus from any other cpuset. Whenever a new
438 * exclusive cpuset is created, we also create and attach a new root-domain
448 * The "RT overload" flag: it gets set if a CPU has more than
449 * one runnable RT task.
456 * By default the system creates a single root-domain with all cpus as
457 * members (mimicking the global state we have today).
459 static struct root_domain def_root_domain
;
464 * This is the main, per-CPU runqueue data structure.
466 * Locking rule: those places that want to lock multiple runqueues
467 * (such as the load balancing or the thread migration code), lock
468 * acquire operations must be ordered by ascending &runqueue.
475 * nr_running and cpu_load should be in the same cacheline because
476 * remote CPUs use both these fields when doing load calculation.
478 unsigned long nr_running
;
479 #define CPU_LOAD_IDX_MAX 5
480 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
481 unsigned char idle_at_tick
;
483 unsigned long last_tick_seen
;
484 unsigned char in_nohz_recently
;
486 /* capture load from *all* tasks on this cpu: */
487 struct load_weight load
;
488 unsigned long nr_load_updates
;
494 #ifdef CONFIG_FAIR_GROUP_SCHED
495 /* list of leaf cfs_rq on this cpu: */
496 struct list_head leaf_cfs_rq_list
;
498 #ifdef CONFIG_RT_GROUP_SCHED
499 struct list_head leaf_rt_rq_list
;
503 * This is part of a global counter where only the total sum
504 * over all CPUs matters. A task can increase this counter on
505 * one CPU and if it got migrated afterwards it may decrease
506 * it on another CPU. Always updated under the runqueue lock:
508 unsigned long nr_uninterruptible
;
510 struct task_struct
*curr
, *idle
;
511 unsigned long next_balance
;
512 struct mm_struct
*prev_mm
;
514 u64 clock
, prev_clock_raw
;
517 unsigned int clock_warps
, clock_overflows
, clock_underflows
;
519 unsigned int clock_deep_idle_events
;
525 struct root_domain
*rd
;
526 struct sched_domain
*sd
;
528 /* For active balancing */
531 /* cpu of this runqueue: */
534 struct task_struct
*migration_thread
;
535 struct list_head migration_queue
;
538 #ifdef CONFIG_SCHED_HRTICK
539 unsigned long hrtick_flags
;
540 ktime_t hrtick_expire
;
541 struct hrtimer hrtick_timer
;
544 #ifdef CONFIG_SCHEDSTATS
546 struct sched_info rq_sched_info
;
548 /* sys_sched_yield() stats */
549 unsigned int yld_exp_empty
;
550 unsigned int yld_act_empty
;
551 unsigned int yld_both_empty
;
552 unsigned int yld_count
;
554 /* schedule() stats */
555 unsigned int sched_switch
;
556 unsigned int sched_count
;
557 unsigned int sched_goidle
;
559 /* try_to_wake_up() stats */
560 unsigned int ttwu_count
;
561 unsigned int ttwu_local
;
564 unsigned int bkl_count
;
566 struct lock_class_key rq_lock_key
;
569 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
571 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
)
573 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
);
576 static inline int cpu_of(struct rq
*rq
)
586 static inline bool nohz_on(int cpu
)
588 return tick_get_tick_sched(cpu
)->nohz_mode
!= NOHZ_MODE_INACTIVE
;
591 static inline u64
max_skipped_ticks(struct rq
*rq
)
593 return nohz_on(cpu_of(rq
)) ? jiffies
- rq
->last_tick_seen
+ 2 : 1;
596 static inline void update_last_tick_seen(struct rq
*rq
)
598 rq
->last_tick_seen
= jiffies
;
601 static inline u64
max_skipped_ticks(struct rq
*rq
)
606 static inline void update_last_tick_seen(struct rq
*rq
)
612 * Update the per-runqueue clock, as finegrained as the platform can give
613 * us, but without assuming monotonicity, etc.:
615 static void __update_rq_clock(struct rq
*rq
)
617 u64 prev_raw
= rq
->prev_clock_raw
;
618 u64 now
= sched_clock();
619 s64 delta
= now
- prev_raw
;
620 u64 clock
= rq
->clock
;
622 #ifdef CONFIG_SCHED_DEBUG
623 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
626 * Protect against sched_clock() occasionally going backwards:
628 if (unlikely(delta
< 0)) {
633 * Catch too large forward jumps too:
635 u64 max_jump
= max_skipped_ticks(rq
) * TICK_NSEC
;
636 u64 max_time
= rq
->tick_timestamp
+ max_jump
;
638 if (unlikely(clock
+ delta
> max_time
)) {
639 if (clock
< max_time
)
643 rq
->clock_overflows
++;
645 if (unlikely(delta
> rq
->clock_max_delta
))
646 rq
->clock_max_delta
= delta
;
651 rq
->prev_clock_raw
= now
;
655 static void update_rq_clock(struct rq
*rq
)
657 if (likely(smp_processor_id() == cpu_of(rq
)))
658 __update_rq_clock(rq
);
662 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
663 * See detach_destroy_domains: synchronize_sched for details.
665 * The domain tree of any CPU may only be accessed from within
666 * preempt-disabled sections.
668 #define for_each_domain(cpu, __sd) \
669 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
671 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
672 #define this_rq() (&__get_cpu_var(runqueues))
673 #define task_rq(p) cpu_rq(task_cpu(p))
674 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
677 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
679 #ifdef CONFIG_SCHED_DEBUG
680 # define const_debug __read_mostly
682 # define const_debug static const
686 * Debugging: various feature bits
689 SCHED_FEAT_NEW_FAIR_SLEEPERS
= 1,
690 SCHED_FEAT_WAKEUP_PREEMPT
= 2,
691 SCHED_FEAT_START_DEBIT
= 4,
692 SCHED_FEAT_AFFINE_WAKEUPS
= 8,
693 SCHED_FEAT_CACHE_HOT_BUDDY
= 16,
694 SCHED_FEAT_SYNC_WAKEUPS
= 32,
695 SCHED_FEAT_HRTICK
= 64,
696 SCHED_FEAT_DOUBLE_TICK
= 128,
697 SCHED_FEAT_NORMALIZED_SLEEPER
= 256,
700 const_debug
unsigned int sysctl_sched_features
=
701 SCHED_FEAT_NEW_FAIR_SLEEPERS
* 1 |
702 SCHED_FEAT_WAKEUP_PREEMPT
* 1 |
703 SCHED_FEAT_START_DEBIT
* 1 |
704 SCHED_FEAT_AFFINE_WAKEUPS
* 1 |
705 SCHED_FEAT_CACHE_HOT_BUDDY
* 1 |
706 SCHED_FEAT_SYNC_WAKEUPS
* 1 |
707 SCHED_FEAT_HRTICK
* 1 |
708 SCHED_FEAT_DOUBLE_TICK
* 0 |
709 SCHED_FEAT_NORMALIZED_SLEEPER
* 1;
711 #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
714 * Number of tasks to iterate in a single balance run.
715 * Limited because this is done with IRQs disabled.
717 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
720 * period over which we measure -rt task cpu usage in us.
723 unsigned int sysctl_sched_rt_period
= 1000000;
725 static __read_mostly
int scheduler_running
;
728 * part of the period that we allow rt tasks to run in us.
731 int sysctl_sched_rt_runtime
= 950000;
733 static inline u64
global_rt_period(void)
735 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
738 static inline u64
global_rt_runtime(void)
740 if (sysctl_sched_rt_period
< 0)
743 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
746 static const unsigned long long time_sync_thresh
= 100000;
748 static DEFINE_PER_CPU(unsigned long long, time_offset
);
749 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time
);
752 * Global lock which we take every now and then to synchronize
753 * the CPUs time. This method is not warp-safe, but it's good
754 * enough to synchronize slowly diverging time sources and thus
755 * it's good enough for tracing:
757 static DEFINE_SPINLOCK(time_sync_lock
);
758 static unsigned long long prev_global_time
;
760 static unsigned long long __sync_cpu_clock(cycles_t time
, int cpu
)
764 spin_lock_irqsave(&time_sync_lock
, flags
);
766 if (time
< prev_global_time
) {
767 per_cpu(time_offset
, cpu
) += prev_global_time
- time
;
768 time
= prev_global_time
;
770 prev_global_time
= time
;
773 spin_unlock_irqrestore(&time_sync_lock
, flags
);
778 static unsigned long long __cpu_clock(int cpu
)
780 unsigned long long now
;
785 * Only call sched_clock() if the scheduler has already been
786 * initialized (some code might call cpu_clock() very early):
788 if (unlikely(!scheduler_running
))
791 local_irq_save(flags
);
795 local_irq_restore(flags
);
801 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
802 * clock constructed from sched_clock():
804 unsigned long long cpu_clock(int cpu
)
806 unsigned long long prev_cpu_time
, time
, delta_time
;
808 prev_cpu_time
= per_cpu(prev_cpu_time
, cpu
);
809 time
= __cpu_clock(cpu
) + per_cpu(time_offset
, cpu
);
810 delta_time
= time
-prev_cpu_time
;
812 if (unlikely(delta_time
> time_sync_thresh
))
813 time
= __sync_cpu_clock(time
, cpu
);
817 EXPORT_SYMBOL_GPL(cpu_clock
);
819 #ifndef prepare_arch_switch
820 # define prepare_arch_switch(next) do { } while (0)
822 #ifndef finish_arch_switch
823 # define finish_arch_switch(prev) do { } while (0)
826 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
828 return rq
->curr
== p
;
831 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
832 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
834 return task_current(rq
, p
);
837 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
841 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
843 #ifdef CONFIG_DEBUG_SPINLOCK
844 /* this is a valid case when another task releases the spinlock */
845 rq
->lock
.owner
= current
;
848 * If we are tracking spinlock dependencies then we have to
849 * fix up the runqueue lock - which gets 'carried over' from
852 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
854 spin_unlock_irq(&rq
->lock
);
857 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
858 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
863 return task_current(rq
, p
);
867 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
871 * We can optimise this out completely for !SMP, because the
872 * SMP rebalancing from interrupt is the only thing that cares
877 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
878 spin_unlock_irq(&rq
->lock
);
880 spin_unlock(&rq
->lock
);
884 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
888 * After ->oncpu is cleared, the task can be moved to a different CPU.
889 * We must ensure this doesn't happen until the switch is completely
895 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
899 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
902 * __task_rq_lock - lock the runqueue a given task resides on.
903 * Must be called interrupts disabled.
905 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
909 struct rq
*rq
= task_rq(p
);
910 spin_lock(&rq
->lock
);
911 if (likely(rq
== task_rq(p
)))
913 spin_unlock(&rq
->lock
);
918 * task_rq_lock - lock the runqueue a given task resides on and disable
919 * interrupts. Note the ordering: we can safely lookup the task_rq without
920 * explicitly disabling preemption.
922 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
928 local_irq_save(*flags
);
930 spin_lock(&rq
->lock
);
931 if (likely(rq
== task_rq(p
)))
933 spin_unlock_irqrestore(&rq
->lock
, *flags
);
937 static void __task_rq_unlock(struct rq
*rq
)
940 spin_unlock(&rq
->lock
);
943 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
946 spin_unlock_irqrestore(&rq
->lock
, *flags
);
950 * this_rq_lock - lock this runqueue and disable interrupts.
952 static struct rq
*this_rq_lock(void)
959 spin_lock(&rq
->lock
);
965 * We are going deep-idle (irqs are disabled):
967 void sched_clock_idle_sleep_event(void)
969 struct rq
*rq
= cpu_rq(smp_processor_id());
971 spin_lock(&rq
->lock
);
972 __update_rq_clock(rq
);
973 spin_unlock(&rq
->lock
);
974 rq
->clock_deep_idle_events
++;
976 EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event
);
979 * We just idled delta nanoseconds (called with irqs disabled):
981 void sched_clock_idle_wakeup_event(u64 delta_ns
)
983 struct rq
*rq
= cpu_rq(smp_processor_id());
984 u64 now
= sched_clock();
986 rq
->idle_clock
+= delta_ns
;
988 * Override the previous timestamp and ignore all
989 * sched_clock() deltas that occured while we idled,
990 * and use the PM-provided delta_ns to advance the
993 spin_lock(&rq
->lock
);
994 rq
->prev_clock_raw
= now
;
995 rq
->clock
+= delta_ns
;
996 spin_unlock(&rq
->lock
);
997 touch_softlockup_watchdog();
999 EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event
);
1001 static void __resched_task(struct task_struct
*p
, int tif_bit
);
1003 static inline void resched_task(struct task_struct
*p
)
1005 __resched_task(p
, TIF_NEED_RESCHED
);
1008 #ifdef CONFIG_SCHED_HRTICK
1010 * Use HR-timers to deliver accurate preemption points.
1012 * Its all a bit involved since we cannot program an hrt while holding the
1013 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1016 * When we get rescheduled we reprogram the hrtick_timer outside of the
1019 static inline void resched_hrt(struct task_struct
*p
)
1021 __resched_task(p
, TIF_HRTICK_RESCHED
);
1024 static inline void resched_rq(struct rq
*rq
)
1026 unsigned long flags
;
1028 spin_lock_irqsave(&rq
->lock
, flags
);
1029 resched_task(rq
->curr
);
1030 spin_unlock_irqrestore(&rq
->lock
, flags
);
1034 HRTICK_SET
, /* re-programm hrtick_timer */
1035 HRTICK_RESET
, /* not a new slice */
1040 * - enabled by features
1041 * - hrtimer is actually high res
1043 static inline int hrtick_enabled(struct rq
*rq
)
1045 if (!sched_feat(HRTICK
))
1047 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1051 * Called to set the hrtick timer state.
1053 * called with rq->lock held and irqs disabled
1055 static void hrtick_start(struct rq
*rq
, u64 delay
, int reset
)
1057 assert_spin_locked(&rq
->lock
);
1060 * preempt at: now + delay
1063 ktime_add_ns(rq
->hrtick_timer
.base
->get_time(), delay
);
1065 * indicate we need to program the timer
1067 __set_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1069 __set_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1072 * New slices are called from the schedule path and don't need a
1073 * forced reschedule.
1076 resched_hrt(rq
->curr
);
1079 static void hrtick_clear(struct rq
*rq
)
1081 if (hrtimer_active(&rq
->hrtick_timer
))
1082 hrtimer_cancel(&rq
->hrtick_timer
);
1086 * Update the timer from the possible pending state.
1088 static void hrtick_set(struct rq
*rq
)
1092 unsigned long flags
;
1094 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1096 spin_lock_irqsave(&rq
->lock
, flags
);
1097 set
= __test_and_clear_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1098 reset
= __test_and_clear_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1099 time
= rq
->hrtick_expire
;
1100 clear_thread_flag(TIF_HRTICK_RESCHED
);
1101 spin_unlock_irqrestore(&rq
->lock
, flags
);
1104 hrtimer_start(&rq
->hrtick_timer
, time
, HRTIMER_MODE_ABS
);
1105 if (reset
&& !hrtimer_active(&rq
->hrtick_timer
))
1112 * High-resolution timer tick.
1113 * Runs from hardirq context with interrupts disabled.
1115 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1117 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1119 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1121 spin_lock(&rq
->lock
);
1122 __update_rq_clock(rq
);
1123 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1124 spin_unlock(&rq
->lock
);
1126 return HRTIMER_NORESTART
;
1129 static inline void init_rq_hrtick(struct rq
*rq
)
1131 rq
->hrtick_flags
= 0;
1132 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1133 rq
->hrtick_timer
.function
= hrtick
;
1134 rq
->hrtick_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1137 void hrtick_resched(void)
1140 unsigned long flags
;
1142 if (!test_thread_flag(TIF_HRTICK_RESCHED
))
1145 local_irq_save(flags
);
1146 rq
= cpu_rq(smp_processor_id());
1148 local_irq_restore(flags
);
1151 static inline void hrtick_clear(struct rq
*rq
)
1155 static inline void hrtick_set(struct rq
*rq
)
1159 static inline void init_rq_hrtick(struct rq
*rq
)
1163 void hrtick_resched(void)
1169 * resched_task - mark a task 'to be rescheduled now'.
1171 * On UP this means the setting of the need_resched flag, on SMP it
1172 * might also involve a cross-CPU call to trigger the scheduler on
1177 #ifndef tsk_is_polling
1178 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1181 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1185 assert_spin_locked(&task_rq(p
)->lock
);
1187 if (unlikely(test_tsk_thread_flag(p
, tif_bit
)))
1190 set_tsk_thread_flag(p
, tif_bit
);
1193 if (cpu
== smp_processor_id())
1196 /* NEED_RESCHED must be visible before we test polling */
1198 if (!tsk_is_polling(p
))
1199 smp_send_reschedule(cpu
);
1202 static void resched_cpu(int cpu
)
1204 struct rq
*rq
= cpu_rq(cpu
);
1205 unsigned long flags
;
1207 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1209 resched_task(cpu_curr(cpu
));
1210 spin_unlock_irqrestore(&rq
->lock
, flags
);
1215 * When add_timer_on() enqueues a timer into the timer wheel of an
1216 * idle CPU then this timer might expire before the next timer event
1217 * which is scheduled to wake up that CPU. In case of a completely
1218 * idle system the next event might even be infinite time into the
1219 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1220 * leaves the inner idle loop so the newly added timer is taken into
1221 * account when the CPU goes back to idle and evaluates the timer
1222 * wheel for the next timer event.
1224 void wake_up_idle_cpu(int cpu
)
1226 struct rq
*rq
= cpu_rq(cpu
);
1228 if (cpu
== smp_processor_id())
1232 * This is safe, as this function is called with the timer
1233 * wheel base lock of (cpu) held. When the CPU is on the way
1234 * to idle and has not yet set rq->curr to idle then it will
1235 * be serialized on the timer wheel base lock and take the new
1236 * timer into account automatically.
1238 if (rq
->curr
!= rq
->idle
)
1242 * We can set TIF_RESCHED on the idle task of the other CPU
1243 * lockless. The worst case is that the other CPU runs the
1244 * idle task through an additional NOOP schedule()
1246 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1248 /* NEED_RESCHED must be visible before we test polling */
1250 if (!tsk_is_polling(rq
->idle
))
1251 smp_send_reschedule(cpu
);
1256 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1258 assert_spin_locked(&task_rq(p
)->lock
);
1259 set_tsk_thread_flag(p
, tif_bit
);
1263 #if BITS_PER_LONG == 32
1264 # define WMULT_CONST (~0UL)
1266 # define WMULT_CONST (1UL << 32)
1269 #define WMULT_SHIFT 32
1272 * Shift right and round:
1274 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1276 static unsigned long
1277 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1278 struct load_weight
*lw
)
1282 if (unlikely(!lw
->inv_weight
))
1283 lw
->inv_weight
= (WMULT_CONST
-lw
->weight
/2) / (lw
->weight
+1);
1285 tmp
= (u64
)delta_exec
* weight
;
1287 * Check whether we'd overflow the 64-bit multiplication:
1289 if (unlikely(tmp
> WMULT_CONST
))
1290 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1293 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1295 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1298 static inline unsigned long
1299 calc_delta_fair(unsigned long delta_exec
, struct load_weight
*lw
)
1301 return calc_delta_mine(delta_exec
, NICE_0_LOAD
, lw
);
1304 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1310 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1317 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1318 * of tasks with abnormal "nice" values across CPUs the contribution that
1319 * each task makes to its run queue's load is weighted according to its
1320 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1321 * scaled version of the new time slice allocation that they receive on time
1325 #define WEIGHT_IDLEPRIO 2
1326 #define WMULT_IDLEPRIO (1 << 31)
1329 * Nice levels are multiplicative, with a gentle 10% change for every
1330 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1331 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1332 * that remained on nice 0.
1334 * The "10% effect" is relative and cumulative: from _any_ nice level,
1335 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1336 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1337 * If a task goes up by ~10% and another task goes down by ~10% then
1338 * the relative distance between them is ~25%.)
1340 static const int prio_to_weight
[40] = {
1341 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1342 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1343 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1344 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1345 /* 0 */ 1024, 820, 655, 526, 423,
1346 /* 5 */ 335, 272, 215, 172, 137,
1347 /* 10 */ 110, 87, 70, 56, 45,
1348 /* 15 */ 36, 29, 23, 18, 15,
1352 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1354 * In cases where the weight does not change often, we can use the
1355 * precalculated inverse to speed up arithmetics by turning divisions
1356 * into multiplications:
1358 static const u32 prio_to_wmult
[40] = {
1359 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1360 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1361 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1362 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1363 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1364 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1365 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1366 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1369 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1372 * runqueue iterator, to support SMP load-balancing between different
1373 * scheduling classes, without having to expose their internal data
1374 * structures to the load-balancing proper:
1376 struct rq_iterator
{
1378 struct task_struct
*(*start
)(void *);
1379 struct task_struct
*(*next
)(void *);
1383 static unsigned long
1384 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1385 unsigned long max_load_move
, struct sched_domain
*sd
,
1386 enum cpu_idle_type idle
, int *all_pinned
,
1387 int *this_best_prio
, struct rq_iterator
*iterator
);
1390 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1391 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1392 struct rq_iterator
*iterator
);
1395 #ifdef CONFIG_CGROUP_CPUACCT
1396 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1398 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1402 static unsigned long source_load(int cpu
, int type
);
1403 static unsigned long target_load(int cpu
, int type
);
1404 static unsigned long cpu_avg_load_per_task(int cpu
);
1405 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1406 #endif /* CONFIG_SMP */
1408 #include "sched_stats.h"
1409 #include "sched_idletask.c"
1410 #include "sched_fair.c"
1411 #include "sched_rt.c"
1412 #ifdef CONFIG_SCHED_DEBUG
1413 # include "sched_debug.c"
1416 #define sched_class_highest (&rt_sched_class)
1418 static inline void inc_load(struct rq
*rq
, const struct task_struct
*p
)
1420 update_load_add(&rq
->load
, p
->se
.load
.weight
);
1423 static inline void dec_load(struct rq
*rq
, const struct task_struct
*p
)
1425 update_load_sub(&rq
->load
, p
->se
.load
.weight
);
1428 static void inc_nr_running(struct task_struct
*p
, struct rq
*rq
)
1434 static void dec_nr_running(struct task_struct
*p
, struct rq
*rq
)
1440 static void set_load_weight(struct task_struct
*p
)
1442 if (task_has_rt_policy(p
)) {
1443 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1444 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1449 * SCHED_IDLE tasks get minimal weight:
1451 if (p
->policy
== SCHED_IDLE
) {
1452 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1453 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1457 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1458 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1461 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1463 sched_info_queued(p
);
1464 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1468 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1470 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1475 * __normal_prio - return the priority that is based on the static prio
1477 static inline int __normal_prio(struct task_struct
*p
)
1479 return p
->static_prio
;
1483 * Calculate the expected normal priority: i.e. priority
1484 * without taking RT-inheritance into account. Might be
1485 * boosted by interactivity modifiers. Changes upon fork,
1486 * setprio syscalls, and whenever the interactivity
1487 * estimator recalculates.
1489 static inline int normal_prio(struct task_struct
*p
)
1493 if (task_has_rt_policy(p
))
1494 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1496 prio
= __normal_prio(p
);
1501 * Calculate the current priority, i.e. the priority
1502 * taken into account by the scheduler. This value might
1503 * be boosted by RT tasks, or might be boosted by
1504 * interactivity modifiers. Will be RT if the task got
1505 * RT-boosted. If not then it returns p->normal_prio.
1507 static int effective_prio(struct task_struct
*p
)
1509 p
->normal_prio
= normal_prio(p
);
1511 * If we are RT tasks or we were boosted to RT priority,
1512 * keep the priority unchanged. Otherwise, update priority
1513 * to the normal priority:
1515 if (!rt_prio(p
->prio
))
1516 return p
->normal_prio
;
1521 * activate_task - move a task to the runqueue.
1523 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1525 if (task_contributes_to_load(p
))
1526 rq
->nr_uninterruptible
--;
1528 enqueue_task(rq
, p
, wakeup
);
1529 inc_nr_running(p
, rq
);
1533 * deactivate_task - remove a task from the runqueue.
1535 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1537 if (task_contributes_to_load(p
))
1538 rq
->nr_uninterruptible
++;
1540 dequeue_task(rq
, p
, sleep
);
1541 dec_nr_running(p
, rq
);
1545 * task_curr - is this task currently executing on a CPU?
1546 * @p: the task in question.
1548 inline int task_curr(const struct task_struct
*p
)
1550 return cpu_curr(task_cpu(p
)) == p
;
1553 /* Used instead of source_load when we know the type == 0 */
1554 unsigned long weighted_cpuload(const int cpu
)
1556 return cpu_rq(cpu
)->load
.weight
;
1559 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1561 set_task_rq(p
, cpu
);
1564 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1565 * successfuly executed on another CPU. We must ensure that updates of
1566 * per-task data have been completed by this moment.
1569 task_thread_info(p
)->cpu
= cpu
;
1573 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1574 const struct sched_class
*prev_class
,
1575 int oldprio
, int running
)
1577 if (prev_class
!= p
->sched_class
) {
1578 if (prev_class
->switched_from
)
1579 prev_class
->switched_from(rq
, p
, running
);
1580 p
->sched_class
->switched_to(rq
, p
, running
);
1582 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1588 * Is this task likely cache-hot:
1591 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1596 * Buddy candidates are cache hot:
1598 if (sched_feat(CACHE_HOT_BUDDY
) && (&p
->se
== cfs_rq_of(&p
->se
)->next
))
1601 if (p
->sched_class
!= &fair_sched_class
)
1604 if (sysctl_sched_migration_cost
== -1)
1606 if (sysctl_sched_migration_cost
== 0)
1609 delta
= now
- p
->se
.exec_start
;
1611 return delta
< (s64
)sysctl_sched_migration_cost
;
1615 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1617 int old_cpu
= task_cpu(p
);
1618 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1619 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1620 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1623 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1625 #ifdef CONFIG_SCHEDSTATS
1626 if (p
->se
.wait_start
)
1627 p
->se
.wait_start
-= clock_offset
;
1628 if (p
->se
.sleep_start
)
1629 p
->se
.sleep_start
-= clock_offset
;
1630 if (p
->se
.block_start
)
1631 p
->se
.block_start
-= clock_offset
;
1632 if (old_cpu
!= new_cpu
) {
1633 schedstat_inc(p
, se
.nr_migrations
);
1634 if (task_hot(p
, old_rq
->clock
, NULL
))
1635 schedstat_inc(p
, se
.nr_forced2_migrations
);
1638 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1639 new_cfsrq
->min_vruntime
;
1641 __set_task_cpu(p
, new_cpu
);
1644 struct migration_req
{
1645 struct list_head list
;
1647 struct task_struct
*task
;
1650 struct completion done
;
1654 * The task's runqueue lock must be held.
1655 * Returns true if you have to wait for migration thread.
1658 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1660 struct rq
*rq
= task_rq(p
);
1663 * If the task is not on a runqueue (and not running), then
1664 * it is sufficient to simply update the task's cpu field.
1666 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1667 set_task_cpu(p
, dest_cpu
);
1671 init_completion(&req
->done
);
1673 req
->dest_cpu
= dest_cpu
;
1674 list_add(&req
->list
, &rq
->migration_queue
);
1680 * wait_task_inactive - wait for a thread to unschedule.
1682 * The caller must ensure that the task *will* unschedule sometime soon,
1683 * else this function might spin for a *long* time. This function can't
1684 * be called with interrupts off, or it may introduce deadlock with
1685 * smp_call_function() if an IPI is sent by the same process we are
1686 * waiting to become inactive.
1688 void wait_task_inactive(struct task_struct
*p
)
1690 unsigned long flags
;
1696 * We do the initial early heuristics without holding
1697 * any task-queue locks at all. We'll only try to get
1698 * the runqueue lock when things look like they will
1704 * If the task is actively running on another CPU
1705 * still, just relax and busy-wait without holding
1708 * NOTE! Since we don't hold any locks, it's not
1709 * even sure that "rq" stays as the right runqueue!
1710 * But we don't care, since "task_running()" will
1711 * return false if the runqueue has changed and p
1712 * is actually now running somewhere else!
1714 while (task_running(rq
, p
))
1718 * Ok, time to look more closely! We need the rq
1719 * lock now, to be *sure*. If we're wrong, we'll
1720 * just go back and repeat.
1722 rq
= task_rq_lock(p
, &flags
);
1723 running
= task_running(rq
, p
);
1724 on_rq
= p
->se
.on_rq
;
1725 task_rq_unlock(rq
, &flags
);
1728 * Was it really running after all now that we
1729 * checked with the proper locks actually held?
1731 * Oops. Go back and try again..
1733 if (unlikely(running
)) {
1739 * It's not enough that it's not actively running,
1740 * it must be off the runqueue _entirely_, and not
1743 * So if it wa still runnable (but just not actively
1744 * running right now), it's preempted, and we should
1745 * yield - it could be a while.
1747 if (unlikely(on_rq
)) {
1748 schedule_timeout_uninterruptible(1);
1753 * Ahh, all good. It wasn't running, and it wasn't
1754 * runnable, which means that it will never become
1755 * running in the future either. We're all done!
1762 * kick_process - kick a running thread to enter/exit the kernel
1763 * @p: the to-be-kicked thread
1765 * Cause a process which is running on another CPU to enter
1766 * kernel-mode, without any delay. (to get signals handled.)
1768 * NOTE: this function doesnt have to take the runqueue lock,
1769 * because all it wants to ensure is that the remote task enters
1770 * the kernel. If the IPI races and the task has been migrated
1771 * to another CPU then no harm is done and the purpose has been
1774 void kick_process(struct task_struct
*p
)
1780 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1781 smp_send_reschedule(cpu
);
1786 * Return a low guess at the load of a migration-source cpu weighted
1787 * according to the scheduling class and "nice" value.
1789 * We want to under-estimate the load of migration sources, to
1790 * balance conservatively.
1792 static unsigned long source_load(int cpu
, int type
)
1794 struct rq
*rq
= cpu_rq(cpu
);
1795 unsigned long total
= weighted_cpuload(cpu
);
1800 return min(rq
->cpu_load
[type
-1], total
);
1804 * Return a high guess at the load of a migration-target cpu weighted
1805 * according to the scheduling class and "nice" value.
1807 static unsigned long target_load(int cpu
, int type
)
1809 struct rq
*rq
= cpu_rq(cpu
);
1810 unsigned long total
= weighted_cpuload(cpu
);
1815 return max(rq
->cpu_load
[type
-1], total
);
1819 * Return the average load per task on the cpu's run queue
1821 static unsigned long cpu_avg_load_per_task(int cpu
)
1823 struct rq
*rq
= cpu_rq(cpu
);
1824 unsigned long total
= weighted_cpuload(cpu
);
1825 unsigned long n
= rq
->nr_running
;
1827 return n
? total
/ n
: SCHED_LOAD_SCALE
;
1831 * find_idlest_group finds and returns the least busy CPU group within the
1834 static struct sched_group
*
1835 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
1837 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
1838 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
1839 int load_idx
= sd
->forkexec_idx
;
1840 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
1843 unsigned long load
, avg_load
;
1847 /* Skip over this group if it has no CPUs allowed */
1848 if (!cpus_intersects(group
->cpumask
, p
->cpus_allowed
))
1851 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
1853 /* Tally up the load of all CPUs in the group */
1856 for_each_cpu_mask(i
, group
->cpumask
) {
1857 /* Bias balancing toward cpus of our domain */
1859 load
= source_load(i
, load_idx
);
1861 load
= target_load(i
, load_idx
);
1866 /* Adjust by relative CPU power of the group */
1867 avg_load
= sg_div_cpu_power(group
,
1868 avg_load
* SCHED_LOAD_SCALE
);
1871 this_load
= avg_load
;
1873 } else if (avg_load
< min_load
) {
1874 min_load
= avg_load
;
1877 } while (group
= group
->next
, group
!= sd
->groups
);
1879 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
1885 * find_idlest_cpu - find the idlest cpu among the cpus in group.
1888 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
,
1891 unsigned long load
, min_load
= ULONG_MAX
;
1895 /* Traverse only the allowed CPUs */
1896 cpus_and(*tmp
, group
->cpumask
, p
->cpus_allowed
);
1898 for_each_cpu_mask(i
, *tmp
) {
1899 load
= weighted_cpuload(i
);
1901 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
1911 * sched_balance_self: balance the current task (running on cpu) in domains
1912 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
1915 * Balance, ie. select the least loaded group.
1917 * Returns the target CPU number, or the same CPU if no balancing is needed.
1919 * preempt must be disabled.
1921 static int sched_balance_self(int cpu
, int flag
)
1923 struct task_struct
*t
= current
;
1924 struct sched_domain
*tmp
, *sd
= NULL
;
1926 for_each_domain(cpu
, tmp
) {
1928 * If power savings logic is enabled for a domain, stop there.
1930 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
1932 if (tmp
->flags
& flag
)
1937 cpumask_t span
, tmpmask
;
1938 struct sched_group
*group
;
1939 int new_cpu
, weight
;
1941 if (!(sd
->flags
& flag
)) {
1947 group
= find_idlest_group(sd
, t
, cpu
);
1953 new_cpu
= find_idlest_cpu(group
, t
, cpu
, &tmpmask
);
1954 if (new_cpu
== -1 || new_cpu
== cpu
) {
1955 /* Now try balancing at a lower domain level of cpu */
1960 /* Now try balancing at a lower domain level of new_cpu */
1963 weight
= cpus_weight(span
);
1964 for_each_domain(cpu
, tmp
) {
1965 if (weight
<= cpus_weight(tmp
->span
))
1967 if (tmp
->flags
& flag
)
1970 /* while loop will break here if sd == NULL */
1976 #endif /* CONFIG_SMP */
1979 * try_to_wake_up - wake up a thread
1980 * @p: the to-be-woken-up thread
1981 * @state: the mask of task states that can be woken
1982 * @sync: do a synchronous wakeup?
1984 * Put it on the run-queue if it's not already there. The "current"
1985 * thread is always on the run-queue (except when the actual
1986 * re-schedule is in progress), and as such you're allowed to do
1987 * the simpler "current->state = TASK_RUNNING" to mark yourself
1988 * runnable without the overhead of this.
1990 * returns failure only if the task is already active.
1992 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
1994 int cpu
, orig_cpu
, this_cpu
, success
= 0;
1995 unsigned long flags
;
1999 if (!sched_feat(SYNC_WAKEUPS
))
2003 rq
= task_rq_lock(p
, &flags
);
2004 old_state
= p
->state
;
2005 if (!(old_state
& state
))
2013 this_cpu
= smp_processor_id();
2016 if (unlikely(task_running(rq
, p
)))
2019 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2020 if (cpu
!= orig_cpu
) {
2021 set_task_cpu(p
, cpu
);
2022 task_rq_unlock(rq
, &flags
);
2023 /* might preempt at this point */
2024 rq
= task_rq_lock(p
, &flags
);
2025 old_state
= p
->state
;
2026 if (!(old_state
& state
))
2031 this_cpu
= smp_processor_id();
2035 #ifdef CONFIG_SCHEDSTATS
2036 schedstat_inc(rq
, ttwu_count
);
2037 if (cpu
== this_cpu
)
2038 schedstat_inc(rq
, ttwu_local
);
2040 struct sched_domain
*sd
;
2041 for_each_domain(this_cpu
, sd
) {
2042 if (cpu_isset(cpu
, sd
->span
)) {
2043 schedstat_inc(sd
, ttwu_wake_remote
);
2051 #endif /* CONFIG_SMP */
2052 schedstat_inc(p
, se
.nr_wakeups
);
2054 schedstat_inc(p
, se
.nr_wakeups_sync
);
2055 if (orig_cpu
!= cpu
)
2056 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2057 if (cpu
== this_cpu
)
2058 schedstat_inc(p
, se
.nr_wakeups_local
);
2060 schedstat_inc(p
, se
.nr_wakeups_remote
);
2061 update_rq_clock(rq
);
2062 activate_task(rq
, p
, 1);
2066 check_preempt_curr(rq
, p
);
2068 p
->state
= TASK_RUNNING
;
2070 if (p
->sched_class
->task_wake_up
)
2071 p
->sched_class
->task_wake_up(rq
, p
);
2074 task_rq_unlock(rq
, &flags
);
2079 int wake_up_process(struct task_struct
*p
)
2081 return try_to_wake_up(p
, TASK_ALL
, 0);
2083 EXPORT_SYMBOL(wake_up_process
);
2085 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2087 return try_to_wake_up(p
, state
, 0);
2091 * Perform scheduler related setup for a newly forked process p.
2092 * p is forked by current.
2094 * __sched_fork() is basic setup used by init_idle() too:
2096 static void __sched_fork(struct task_struct
*p
)
2098 p
->se
.exec_start
= 0;
2099 p
->se
.sum_exec_runtime
= 0;
2100 p
->se
.prev_sum_exec_runtime
= 0;
2101 p
->se
.last_wakeup
= 0;
2102 p
->se
.avg_overlap
= 0;
2104 #ifdef CONFIG_SCHEDSTATS
2105 p
->se
.wait_start
= 0;
2106 p
->se
.sum_sleep_runtime
= 0;
2107 p
->se
.sleep_start
= 0;
2108 p
->se
.block_start
= 0;
2109 p
->se
.sleep_max
= 0;
2110 p
->se
.block_max
= 0;
2112 p
->se
.slice_max
= 0;
2116 INIT_LIST_HEAD(&p
->rt
.run_list
);
2119 #ifdef CONFIG_PREEMPT_NOTIFIERS
2120 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2124 * We mark the process as running here, but have not actually
2125 * inserted it onto the runqueue yet. This guarantees that
2126 * nobody will actually run it, and a signal or other external
2127 * event cannot wake it up and insert it on the runqueue either.
2129 p
->state
= TASK_RUNNING
;
2133 * fork()/clone()-time setup:
2135 void sched_fork(struct task_struct
*p
, int clone_flags
)
2137 int cpu
= get_cpu();
2142 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2144 set_task_cpu(p
, cpu
);
2147 * Make sure we do not leak PI boosting priority to the child:
2149 p
->prio
= current
->normal_prio
;
2150 if (!rt_prio(p
->prio
))
2151 p
->sched_class
= &fair_sched_class
;
2153 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2154 if (likely(sched_info_on()))
2155 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2157 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2160 #ifdef CONFIG_PREEMPT
2161 /* Want to start with kernel preemption disabled. */
2162 task_thread_info(p
)->preempt_count
= 1;
2168 * wake_up_new_task - wake up a newly created task for the first time.
2170 * This function will do some initial scheduler statistics housekeeping
2171 * that must be done for every newly created context, then puts the task
2172 * on the runqueue and wakes it.
2174 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2176 unsigned long flags
;
2179 rq
= task_rq_lock(p
, &flags
);
2180 BUG_ON(p
->state
!= TASK_RUNNING
);
2181 update_rq_clock(rq
);
2183 p
->prio
= effective_prio(p
);
2185 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2186 activate_task(rq
, p
, 0);
2189 * Let the scheduling class do new task startup
2190 * management (if any):
2192 p
->sched_class
->task_new(rq
, p
);
2193 inc_nr_running(p
, rq
);
2195 check_preempt_curr(rq
, p
);
2197 if (p
->sched_class
->task_wake_up
)
2198 p
->sched_class
->task_wake_up(rq
, p
);
2200 task_rq_unlock(rq
, &flags
);
2203 #ifdef CONFIG_PREEMPT_NOTIFIERS
2206 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2207 * @notifier: notifier struct to register
2209 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2211 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2213 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2216 * preempt_notifier_unregister - no longer interested in preemption notifications
2217 * @notifier: notifier struct to unregister
2219 * This is safe to call from within a preemption notifier.
2221 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2223 hlist_del(¬ifier
->link
);
2225 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2227 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2229 struct preempt_notifier
*notifier
;
2230 struct hlist_node
*node
;
2232 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2233 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2237 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2238 struct task_struct
*next
)
2240 struct preempt_notifier
*notifier
;
2241 struct hlist_node
*node
;
2243 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2244 notifier
->ops
->sched_out(notifier
, next
);
2249 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2254 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2255 struct task_struct
*next
)
2262 * prepare_task_switch - prepare to switch tasks
2263 * @rq: the runqueue preparing to switch
2264 * @prev: the current task that is being switched out
2265 * @next: the task we are going to switch to.
2267 * This is called with the rq lock held and interrupts off. It must
2268 * be paired with a subsequent finish_task_switch after the context
2271 * prepare_task_switch sets up locking and calls architecture specific
2275 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2276 struct task_struct
*next
)
2278 fire_sched_out_preempt_notifiers(prev
, next
);
2279 prepare_lock_switch(rq
, next
);
2280 prepare_arch_switch(next
);
2284 * finish_task_switch - clean up after a task-switch
2285 * @rq: runqueue associated with task-switch
2286 * @prev: the thread we just switched away from.
2288 * finish_task_switch must be called after the context switch, paired
2289 * with a prepare_task_switch call before the context switch.
2290 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2291 * and do any other architecture-specific cleanup actions.
2293 * Note that we may have delayed dropping an mm in context_switch(). If
2294 * so, we finish that here outside of the runqueue lock. (Doing it
2295 * with the lock held can cause deadlocks; see schedule() for
2298 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2299 __releases(rq
->lock
)
2301 struct mm_struct
*mm
= rq
->prev_mm
;
2307 * A task struct has one reference for the use as "current".
2308 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2309 * schedule one last time. The schedule call will never return, and
2310 * the scheduled task must drop that reference.
2311 * The test for TASK_DEAD must occur while the runqueue locks are
2312 * still held, otherwise prev could be scheduled on another cpu, die
2313 * there before we look at prev->state, and then the reference would
2315 * Manfred Spraul <manfred@colorfullife.com>
2317 prev_state
= prev
->state
;
2318 finish_arch_switch(prev
);
2319 finish_lock_switch(rq
, prev
);
2321 if (current
->sched_class
->post_schedule
)
2322 current
->sched_class
->post_schedule(rq
);
2325 fire_sched_in_preempt_notifiers(current
);
2328 if (unlikely(prev_state
== TASK_DEAD
)) {
2330 * Remove function-return probe instances associated with this
2331 * task and put them back on the free list.
2333 kprobe_flush_task(prev
);
2334 put_task_struct(prev
);
2339 * schedule_tail - first thing a freshly forked thread must call.
2340 * @prev: the thread we just switched away from.
2342 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2343 __releases(rq
->lock
)
2345 struct rq
*rq
= this_rq();
2347 finish_task_switch(rq
, prev
);
2348 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2349 /* In this case, finish_task_switch does not reenable preemption */
2352 if (current
->set_child_tid
)
2353 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2357 * context_switch - switch to the new MM and the new
2358 * thread's register state.
2361 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2362 struct task_struct
*next
)
2364 struct mm_struct
*mm
, *oldmm
;
2366 prepare_task_switch(rq
, prev
, next
);
2368 oldmm
= prev
->active_mm
;
2370 * For paravirt, this is coupled with an exit in switch_to to
2371 * combine the page table reload and the switch backend into
2374 arch_enter_lazy_cpu_mode();
2376 if (unlikely(!mm
)) {
2377 next
->active_mm
= oldmm
;
2378 atomic_inc(&oldmm
->mm_count
);
2379 enter_lazy_tlb(oldmm
, next
);
2381 switch_mm(oldmm
, mm
, next
);
2383 if (unlikely(!prev
->mm
)) {
2384 prev
->active_mm
= NULL
;
2385 rq
->prev_mm
= oldmm
;
2388 * Since the runqueue lock will be released by the next
2389 * task (which is an invalid locking op but in the case
2390 * of the scheduler it's an obvious special-case), so we
2391 * do an early lockdep release here:
2393 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2394 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2397 /* Here we just switch the register state and the stack. */
2398 switch_to(prev
, next
, prev
);
2402 * this_rq must be evaluated again because prev may have moved
2403 * CPUs since it called schedule(), thus the 'rq' on its stack
2404 * frame will be invalid.
2406 finish_task_switch(this_rq(), prev
);
2410 * nr_running, nr_uninterruptible and nr_context_switches:
2412 * externally visible scheduler statistics: current number of runnable
2413 * threads, current number of uninterruptible-sleeping threads, total
2414 * number of context switches performed since bootup.
2416 unsigned long nr_running(void)
2418 unsigned long i
, sum
= 0;
2420 for_each_online_cpu(i
)
2421 sum
+= cpu_rq(i
)->nr_running
;
2426 unsigned long nr_uninterruptible(void)
2428 unsigned long i
, sum
= 0;
2430 for_each_possible_cpu(i
)
2431 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2434 * Since we read the counters lockless, it might be slightly
2435 * inaccurate. Do not allow it to go below zero though:
2437 if (unlikely((long)sum
< 0))
2443 unsigned long long nr_context_switches(void)
2446 unsigned long long sum
= 0;
2448 for_each_possible_cpu(i
)
2449 sum
+= cpu_rq(i
)->nr_switches
;
2454 unsigned long nr_iowait(void)
2456 unsigned long i
, sum
= 0;
2458 for_each_possible_cpu(i
)
2459 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2464 unsigned long nr_active(void)
2466 unsigned long i
, running
= 0, uninterruptible
= 0;
2468 for_each_online_cpu(i
) {
2469 running
+= cpu_rq(i
)->nr_running
;
2470 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2473 if (unlikely((long)uninterruptible
< 0))
2474 uninterruptible
= 0;
2476 return running
+ uninterruptible
;
2480 * Update rq->cpu_load[] statistics. This function is usually called every
2481 * scheduler tick (TICK_NSEC).
2483 static void update_cpu_load(struct rq
*this_rq
)
2485 unsigned long this_load
= this_rq
->load
.weight
;
2488 this_rq
->nr_load_updates
++;
2490 /* Update our load: */
2491 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2492 unsigned long old_load
, new_load
;
2494 /* scale is effectively 1 << i now, and >> i divides by scale */
2496 old_load
= this_rq
->cpu_load
[i
];
2497 new_load
= this_load
;
2499 * Round up the averaging division if load is increasing. This
2500 * prevents us from getting stuck on 9 if the load is 10, for
2503 if (new_load
> old_load
)
2504 new_load
+= scale
-1;
2505 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2512 * double_rq_lock - safely lock two runqueues
2514 * Note this does not disable interrupts like task_rq_lock,
2515 * you need to do so manually before calling.
2517 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2518 __acquires(rq1
->lock
)
2519 __acquires(rq2
->lock
)
2521 BUG_ON(!irqs_disabled());
2523 spin_lock(&rq1
->lock
);
2524 __acquire(rq2
->lock
); /* Fake it out ;) */
2527 spin_lock(&rq1
->lock
);
2528 spin_lock(&rq2
->lock
);
2530 spin_lock(&rq2
->lock
);
2531 spin_lock(&rq1
->lock
);
2534 update_rq_clock(rq1
);
2535 update_rq_clock(rq2
);
2539 * double_rq_unlock - safely unlock two runqueues
2541 * Note this does not restore interrupts like task_rq_unlock,
2542 * you need to do so manually after calling.
2544 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2545 __releases(rq1
->lock
)
2546 __releases(rq2
->lock
)
2548 spin_unlock(&rq1
->lock
);
2550 spin_unlock(&rq2
->lock
);
2552 __release(rq2
->lock
);
2556 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2558 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
2559 __releases(this_rq
->lock
)
2560 __acquires(busiest
->lock
)
2561 __acquires(this_rq
->lock
)
2565 if (unlikely(!irqs_disabled())) {
2566 /* printk() doesn't work good under rq->lock */
2567 spin_unlock(&this_rq
->lock
);
2570 if (unlikely(!spin_trylock(&busiest
->lock
))) {
2571 if (busiest
< this_rq
) {
2572 spin_unlock(&this_rq
->lock
);
2573 spin_lock(&busiest
->lock
);
2574 spin_lock(&this_rq
->lock
);
2577 spin_lock(&busiest
->lock
);
2583 * If dest_cpu is allowed for this process, migrate the task to it.
2584 * This is accomplished by forcing the cpu_allowed mask to only
2585 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2586 * the cpu_allowed mask is restored.
2588 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2590 struct migration_req req
;
2591 unsigned long flags
;
2594 rq
= task_rq_lock(p
, &flags
);
2595 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
)
2596 || unlikely(cpu_is_offline(dest_cpu
)))
2599 /* force the process onto the specified CPU */
2600 if (migrate_task(p
, dest_cpu
, &req
)) {
2601 /* Need to wait for migration thread (might exit: take ref). */
2602 struct task_struct
*mt
= rq
->migration_thread
;
2604 get_task_struct(mt
);
2605 task_rq_unlock(rq
, &flags
);
2606 wake_up_process(mt
);
2607 put_task_struct(mt
);
2608 wait_for_completion(&req
.done
);
2613 task_rq_unlock(rq
, &flags
);
2617 * sched_exec - execve() is a valuable balancing opportunity, because at
2618 * this point the task has the smallest effective memory and cache footprint.
2620 void sched_exec(void)
2622 int new_cpu
, this_cpu
= get_cpu();
2623 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2625 if (new_cpu
!= this_cpu
)
2626 sched_migrate_task(current
, new_cpu
);
2630 * pull_task - move a task from a remote runqueue to the local runqueue.
2631 * Both runqueues must be locked.
2633 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2634 struct rq
*this_rq
, int this_cpu
)
2636 deactivate_task(src_rq
, p
, 0);
2637 set_task_cpu(p
, this_cpu
);
2638 activate_task(this_rq
, p
, 0);
2640 * Note that idle threads have a prio of MAX_PRIO, for this test
2641 * to be always true for them.
2643 check_preempt_curr(this_rq
, p
);
2647 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2650 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2651 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2655 * We do not migrate tasks that are:
2656 * 1) running (obviously), or
2657 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2658 * 3) are cache-hot on their current CPU.
2660 if (!cpu_isset(this_cpu
, p
->cpus_allowed
)) {
2661 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
2666 if (task_running(rq
, p
)) {
2667 schedstat_inc(p
, se
.nr_failed_migrations_running
);
2672 * Aggressive migration if:
2673 * 1) task is cache cold, or
2674 * 2) too many balance attempts have failed.
2677 if (!task_hot(p
, rq
->clock
, sd
) ||
2678 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
2679 #ifdef CONFIG_SCHEDSTATS
2680 if (task_hot(p
, rq
->clock
, sd
)) {
2681 schedstat_inc(sd
, lb_hot_gained
[idle
]);
2682 schedstat_inc(p
, se
.nr_forced_migrations
);
2688 if (task_hot(p
, rq
->clock
, sd
)) {
2689 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
2695 static unsigned long
2696 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2697 unsigned long max_load_move
, struct sched_domain
*sd
,
2698 enum cpu_idle_type idle
, int *all_pinned
,
2699 int *this_best_prio
, struct rq_iterator
*iterator
)
2701 int loops
= 0, pulled
= 0, pinned
= 0, skip_for_load
;
2702 struct task_struct
*p
;
2703 long rem_load_move
= max_load_move
;
2705 if (max_load_move
== 0)
2711 * Start the load-balancing iterator:
2713 p
= iterator
->start(iterator
->arg
);
2715 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
2718 * To help distribute high priority tasks across CPUs we don't
2719 * skip a task if it will be the highest priority task (i.e. smallest
2720 * prio value) on its new queue regardless of its load weight
2722 skip_for_load
= (p
->se
.load
.weight
>> 1) > rem_load_move
+
2723 SCHED_LOAD_SCALE_FUZZ
;
2724 if ((skip_for_load
&& p
->prio
>= *this_best_prio
) ||
2725 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2726 p
= iterator
->next(iterator
->arg
);
2730 pull_task(busiest
, p
, this_rq
, this_cpu
);
2732 rem_load_move
-= p
->se
.load
.weight
;
2735 * We only want to steal up to the prescribed amount of weighted load.
2737 if (rem_load_move
> 0) {
2738 if (p
->prio
< *this_best_prio
)
2739 *this_best_prio
= p
->prio
;
2740 p
= iterator
->next(iterator
->arg
);
2745 * Right now, this is one of only two places pull_task() is called,
2746 * so we can safely collect pull_task() stats here rather than
2747 * inside pull_task().
2749 schedstat_add(sd
, lb_gained
[idle
], pulled
);
2752 *all_pinned
= pinned
;
2754 return max_load_move
- rem_load_move
;
2758 * move_tasks tries to move up to max_load_move weighted load from busiest to
2759 * this_rq, as part of a balancing operation within domain "sd".
2760 * Returns 1 if successful and 0 otherwise.
2762 * Called with both runqueues locked.
2764 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2765 unsigned long max_load_move
,
2766 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2769 const struct sched_class
*class = sched_class_highest
;
2770 unsigned long total_load_moved
= 0;
2771 int this_best_prio
= this_rq
->curr
->prio
;
2775 class->load_balance(this_rq
, this_cpu
, busiest
,
2776 max_load_move
- total_load_moved
,
2777 sd
, idle
, all_pinned
, &this_best_prio
);
2778 class = class->next
;
2779 } while (class && max_load_move
> total_load_moved
);
2781 return total_load_moved
> 0;
2785 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2786 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2787 struct rq_iterator
*iterator
)
2789 struct task_struct
*p
= iterator
->start(iterator
->arg
);
2793 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2794 pull_task(busiest
, p
, this_rq
, this_cpu
);
2796 * Right now, this is only the second place pull_task()
2797 * is called, so we can safely collect pull_task()
2798 * stats here rather than inside pull_task().
2800 schedstat_inc(sd
, lb_gained
[idle
]);
2804 p
= iterator
->next(iterator
->arg
);
2811 * move_one_task tries to move exactly one task from busiest to this_rq, as
2812 * part of active balancing operations within "domain".
2813 * Returns 1 if successful and 0 otherwise.
2815 * Called with both runqueues locked.
2817 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2818 struct sched_domain
*sd
, enum cpu_idle_type idle
)
2820 const struct sched_class
*class;
2822 for (class = sched_class_highest
; class; class = class->next
)
2823 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
2830 * find_busiest_group finds and returns the busiest CPU group within the
2831 * domain. It calculates and returns the amount of weighted load which
2832 * should be moved to restore balance via the imbalance parameter.
2834 static struct sched_group
*
2835 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
2836 unsigned long *imbalance
, enum cpu_idle_type idle
,
2837 int *sd_idle
, const cpumask_t
*cpus
, int *balance
)
2839 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2840 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
2841 unsigned long max_pull
;
2842 unsigned long busiest_load_per_task
, busiest_nr_running
;
2843 unsigned long this_load_per_task
, this_nr_running
;
2844 int load_idx
, group_imb
= 0;
2845 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2846 int power_savings_balance
= 1;
2847 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
2848 unsigned long min_nr_running
= ULONG_MAX
;
2849 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
2852 max_load
= this_load
= total_load
= total_pwr
= 0;
2853 busiest_load_per_task
= busiest_nr_running
= 0;
2854 this_load_per_task
= this_nr_running
= 0;
2855 if (idle
== CPU_NOT_IDLE
)
2856 load_idx
= sd
->busy_idx
;
2857 else if (idle
== CPU_NEWLY_IDLE
)
2858 load_idx
= sd
->newidle_idx
;
2860 load_idx
= sd
->idle_idx
;
2863 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
2866 int __group_imb
= 0;
2867 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
2868 unsigned long sum_nr_running
, sum_weighted_load
;
2870 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
2873 balance_cpu
= first_cpu(group
->cpumask
);
2875 /* Tally up the load of all CPUs in the group */
2876 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
2878 min_cpu_load
= ~0UL;
2880 for_each_cpu_mask(i
, group
->cpumask
) {
2883 if (!cpu_isset(i
, *cpus
))
2888 if (*sd_idle
&& rq
->nr_running
)
2891 /* Bias balancing toward cpus of our domain */
2893 if (idle_cpu(i
) && !first_idle_cpu
) {
2898 load
= target_load(i
, load_idx
);
2900 load
= source_load(i
, load_idx
);
2901 if (load
> max_cpu_load
)
2902 max_cpu_load
= load
;
2903 if (min_cpu_load
> load
)
2904 min_cpu_load
= load
;
2908 sum_nr_running
+= rq
->nr_running
;
2909 sum_weighted_load
+= weighted_cpuload(i
);
2913 * First idle cpu or the first cpu(busiest) in this sched group
2914 * is eligible for doing load balancing at this and above
2915 * domains. In the newly idle case, we will allow all the cpu's
2916 * to do the newly idle load balance.
2918 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
2919 balance_cpu
!= this_cpu
&& balance
) {
2924 total_load
+= avg_load
;
2925 total_pwr
+= group
->__cpu_power
;
2927 /* Adjust by relative CPU power of the group */
2928 avg_load
= sg_div_cpu_power(group
,
2929 avg_load
* SCHED_LOAD_SCALE
);
2931 if ((max_cpu_load
- min_cpu_load
) > SCHED_LOAD_SCALE
)
2934 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
2937 this_load
= avg_load
;
2939 this_nr_running
= sum_nr_running
;
2940 this_load_per_task
= sum_weighted_load
;
2941 } else if (avg_load
> max_load
&&
2942 (sum_nr_running
> group_capacity
|| __group_imb
)) {
2943 max_load
= avg_load
;
2945 busiest_nr_running
= sum_nr_running
;
2946 busiest_load_per_task
= sum_weighted_load
;
2947 group_imb
= __group_imb
;
2950 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2952 * Busy processors will not participate in power savings
2955 if (idle
== CPU_NOT_IDLE
||
2956 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
2960 * If the local group is idle or completely loaded
2961 * no need to do power savings balance at this domain
2963 if (local_group
&& (this_nr_running
>= group_capacity
||
2965 power_savings_balance
= 0;
2968 * If a group is already running at full capacity or idle,
2969 * don't include that group in power savings calculations
2971 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
2976 * Calculate the group which has the least non-idle load.
2977 * This is the group from where we need to pick up the load
2980 if ((sum_nr_running
< min_nr_running
) ||
2981 (sum_nr_running
== min_nr_running
&&
2982 first_cpu(group
->cpumask
) <
2983 first_cpu(group_min
->cpumask
))) {
2985 min_nr_running
= sum_nr_running
;
2986 min_load_per_task
= sum_weighted_load
/
2991 * Calculate the group which is almost near its
2992 * capacity but still has some space to pick up some load
2993 * from other group and save more power
2995 if (sum_nr_running
<= group_capacity
- 1) {
2996 if (sum_nr_running
> leader_nr_running
||
2997 (sum_nr_running
== leader_nr_running
&&
2998 first_cpu(group
->cpumask
) >
2999 first_cpu(group_leader
->cpumask
))) {
3000 group_leader
= group
;
3001 leader_nr_running
= sum_nr_running
;
3006 group
= group
->next
;
3007 } while (group
!= sd
->groups
);
3009 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3012 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3014 if (this_load
>= avg_load
||
3015 100*max_load
<= sd
->imbalance_pct
*this_load
)
3018 busiest_load_per_task
/= busiest_nr_running
;
3020 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3023 * We're trying to get all the cpus to the average_load, so we don't
3024 * want to push ourselves above the average load, nor do we wish to
3025 * reduce the max loaded cpu below the average load, as either of these
3026 * actions would just result in more rebalancing later, and ping-pong
3027 * tasks around. Thus we look for the minimum possible imbalance.
3028 * Negative imbalances (*we* are more loaded than anyone else) will
3029 * be counted as no imbalance for these purposes -- we can't fix that
3030 * by pulling tasks to us. Be careful of negative numbers as they'll
3031 * appear as very large values with unsigned longs.
3033 if (max_load
<= busiest_load_per_task
)
3037 * In the presence of smp nice balancing, certain scenarios can have
3038 * max load less than avg load(as we skip the groups at or below
3039 * its cpu_power, while calculating max_load..)
3041 if (max_load
< avg_load
) {
3043 goto small_imbalance
;
3046 /* Don't want to pull so many tasks that a group would go idle */
3047 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3049 /* How much load to actually move to equalise the imbalance */
3050 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3051 (avg_load
- this_load
) * this->__cpu_power
)
3055 * if *imbalance is less than the average load per runnable task
3056 * there is no gaurantee that any tasks will be moved so we'll have
3057 * a think about bumping its value to force at least one task to be
3060 if (*imbalance
< busiest_load_per_task
) {
3061 unsigned long tmp
, pwr_now
, pwr_move
;
3065 pwr_move
= pwr_now
= 0;
3067 if (this_nr_running
) {
3068 this_load_per_task
/= this_nr_running
;
3069 if (busiest_load_per_task
> this_load_per_task
)
3072 this_load_per_task
= SCHED_LOAD_SCALE
;
3074 if (max_load
- this_load
+ SCHED_LOAD_SCALE_FUZZ
>=
3075 busiest_load_per_task
* imbn
) {
3076 *imbalance
= busiest_load_per_task
;
3081 * OK, we don't have enough imbalance to justify moving tasks,
3082 * however we may be able to increase total CPU power used by
3086 pwr_now
+= busiest
->__cpu_power
*
3087 min(busiest_load_per_task
, max_load
);
3088 pwr_now
+= this->__cpu_power
*
3089 min(this_load_per_task
, this_load
);
3090 pwr_now
/= SCHED_LOAD_SCALE
;
3092 /* Amount of load we'd subtract */
3093 tmp
= sg_div_cpu_power(busiest
,
3094 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3096 pwr_move
+= busiest
->__cpu_power
*
3097 min(busiest_load_per_task
, max_load
- tmp
);
3099 /* Amount of load we'd add */
3100 if (max_load
* busiest
->__cpu_power
<
3101 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3102 tmp
= sg_div_cpu_power(this,
3103 max_load
* busiest
->__cpu_power
);
3105 tmp
= sg_div_cpu_power(this,
3106 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3107 pwr_move
+= this->__cpu_power
*
3108 min(this_load_per_task
, this_load
+ tmp
);
3109 pwr_move
/= SCHED_LOAD_SCALE
;
3111 /* Move if we gain throughput */
3112 if (pwr_move
> pwr_now
)
3113 *imbalance
= busiest_load_per_task
;
3119 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3120 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3123 if (this == group_leader
&& group_leader
!= group_min
) {
3124 *imbalance
= min_load_per_task
;
3134 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3137 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3138 unsigned long imbalance
, const cpumask_t
*cpus
)
3140 struct rq
*busiest
= NULL
, *rq
;
3141 unsigned long max_load
= 0;
3144 for_each_cpu_mask(i
, group
->cpumask
) {
3147 if (!cpu_isset(i
, *cpus
))
3151 wl
= weighted_cpuload(i
);
3153 if (rq
->nr_running
== 1 && wl
> imbalance
)
3156 if (wl
> max_load
) {
3166 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3167 * so long as it is large enough.
3169 #define MAX_PINNED_INTERVAL 512
3172 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3173 * tasks if there is an imbalance.
3175 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3176 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3177 int *balance
, cpumask_t
*cpus
)
3179 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3180 struct sched_group
*group
;
3181 unsigned long imbalance
;
3183 unsigned long flags
;
3188 * When power savings policy is enabled for the parent domain, idle
3189 * sibling can pick up load irrespective of busy siblings. In this case,
3190 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3191 * portraying it as CPU_NOT_IDLE.
3193 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3194 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3197 schedstat_inc(sd
, lb_count
[idle
]);
3200 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3207 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3211 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3213 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3217 BUG_ON(busiest
== this_rq
);
3219 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3222 if (busiest
->nr_running
> 1) {
3224 * Attempt to move tasks. If find_busiest_group has found
3225 * an imbalance but busiest->nr_running <= 1, the group is
3226 * still unbalanced. ld_moved simply stays zero, so it is
3227 * correctly treated as an imbalance.
3229 local_irq_save(flags
);
3230 double_rq_lock(this_rq
, busiest
);
3231 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3232 imbalance
, sd
, idle
, &all_pinned
);
3233 double_rq_unlock(this_rq
, busiest
);
3234 local_irq_restore(flags
);
3237 * some other cpu did the load balance for us.
3239 if (ld_moved
&& this_cpu
!= smp_processor_id())
3240 resched_cpu(this_cpu
);
3242 /* All tasks on this runqueue were pinned by CPU affinity */
3243 if (unlikely(all_pinned
)) {
3244 cpu_clear(cpu_of(busiest
), *cpus
);
3245 if (!cpus_empty(*cpus
))
3252 schedstat_inc(sd
, lb_failed
[idle
]);
3253 sd
->nr_balance_failed
++;
3255 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3257 spin_lock_irqsave(&busiest
->lock
, flags
);
3259 /* don't kick the migration_thread, if the curr
3260 * task on busiest cpu can't be moved to this_cpu
3262 if (!cpu_isset(this_cpu
, busiest
->curr
->cpus_allowed
)) {
3263 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3265 goto out_one_pinned
;
3268 if (!busiest
->active_balance
) {
3269 busiest
->active_balance
= 1;
3270 busiest
->push_cpu
= this_cpu
;
3273 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3275 wake_up_process(busiest
->migration_thread
);
3278 * We've kicked active balancing, reset the failure
3281 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3284 sd
->nr_balance_failed
= 0;
3286 if (likely(!active_balance
)) {
3287 /* We were unbalanced, so reset the balancing interval */
3288 sd
->balance_interval
= sd
->min_interval
;
3291 * If we've begun active balancing, start to back off. This
3292 * case may not be covered by the all_pinned logic if there
3293 * is only 1 task on the busy runqueue (because we don't call
3296 if (sd
->balance_interval
< sd
->max_interval
)
3297 sd
->balance_interval
*= 2;
3300 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3301 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3306 schedstat_inc(sd
, lb_balanced
[idle
]);
3308 sd
->nr_balance_failed
= 0;
3311 /* tune up the balancing interval */
3312 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3313 (sd
->balance_interval
< sd
->max_interval
))
3314 sd
->balance_interval
*= 2;
3316 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3317 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3323 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3324 * tasks if there is an imbalance.
3326 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3327 * this_rq is locked.
3330 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3333 struct sched_group
*group
;
3334 struct rq
*busiest
= NULL
;
3335 unsigned long imbalance
;
3343 * When power savings policy is enabled for the parent domain, idle
3344 * sibling can pick up load irrespective of busy siblings. In this case,
3345 * let the state of idle sibling percolate up as IDLE, instead of
3346 * portraying it as CPU_NOT_IDLE.
3348 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3349 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3352 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3354 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3355 &sd_idle
, cpus
, NULL
);
3357 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3361 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3363 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3367 BUG_ON(busiest
== this_rq
);
3369 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3372 if (busiest
->nr_running
> 1) {
3373 /* Attempt to move tasks */
3374 double_lock_balance(this_rq
, busiest
);
3375 /* this_rq->clock is already updated */
3376 update_rq_clock(busiest
);
3377 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3378 imbalance
, sd
, CPU_NEWLY_IDLE
,
3380 spin_unlock(&busiest
->lock
);
3382 if (unlikely(all_pinned
)) {
3383 cpu_clear(cpu_of(busiest
), *cpus
);
3384 if (!cpus_empty(*cpus
))
3390 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3391 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3392 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3395 sd
->nr_balance_failed
= 0;
3400 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3401 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3402 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3404 sd
->nr_balance_failed
= 0;
3410 * idle_balance is called by schedule() if this_cpu is about to become
3411 * idle. Attempts to pull tasks from other CPUs.
3413 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3415 struct sched_domain
*sd
;
3416 int pulled_task
= -1;
3417 unsigned long next_balance
= jiffies
+ HZ
;
3420 for_each_domain(this_cpu
, sd
) {
3421 unsigned long interval
;
3423 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3426 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3427 /* If we've pulled tasks over stop searching: */
3428 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3431 interval
= msecs_to_jiffies(sd
->balance_interval
);
3432 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3433 next_balance
= sd
->last_balance
+ interval
;
3437 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3439 * We are going idle. next_balance may be set based on
3440 * a busy processor. So reset next_balance.
3442 this_rq
->next_balance
= next_balance
;
3447 * active_load_balance is run by migration threads. It pushes running tasks
3448 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3449 * running on each physical CPU where possible, and avoids physical /
3450 * logical imbalances.
3452 * Called with busiest_rq locked.
3454 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3456 int target_cpu
= busiest_rq
->push_cpu
;
3457 struct sched_domain
*sd
;
3458 struct rq
*target_rq
;
3460 /* Is there any task to move? */
3461 if (busiest_rq
->nr_running
<= 1)
3464 target_rq
= cpu_rq(target_cpu
);
3467 * This condition is "impossible", if it occurs
3468 * we need to fix it. Originally reported by
3469 * Bjorn Helgaas on a 128-cpu setup.
3471 BUG_ON(busiest_rq
== target_rq
);
3473 /* move a task from busiest_rq to target_rq */
3474 double_lock_balance(busiest_rq
, target_rq
);
3475 update_rq_clock(busiest_rq
);
3476 update_rq_clock(target_rq
);
3478 /* Search for an sd spanning us and the target CPU. */
3479 for_each_domain(target_cpu
, sd
) {
3480 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3481 cpu_isset(busiest_cpu
, sd
->span
))
3486 schedstat_inc(sd
, alb_count
);
3488 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3490 schedstat_inc(sd
, alb_pushed
);
3492 schedstat_inc(sd
, alb_failed
);
3494 spin_unlock(&target_rq
->lock
);
3499 atomic_t load_balancer
;
3501 } nohz ____cacheline_aligned
= {
3502 .load_balancer
= ATOMIC_INIT(-1),
3503 .cpu_mask
= CPU_MASK_NONE
,
3507 * This routine will try to nominate the ilb (idle load balancing)
3508 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3509 * load balancing on behalf of all those cpus. If all the cpus in the system
3510 * go into this tickless mode, then there will be no ilb owner (as there is
3511 * no need for one) and all the cpus will sleep till the next wakeup event
3514 * For the ilb owner, tick is not stopped. And this tick will be used
3515 * for idle load balancing. ilb owner will still be part of
3518 * While stopping the tick, this cpu will become the ilb owner if there
3519 * is no other owner. And will be the owner till that cpu becomes busy
3520 * or if all cpus in the system stop their ticks at which point
3521 * there is no need for ilb owner.
3523 * When the ilb owner becomes busy, it nominates another owner, during the
3524 * next busy scheduler_tick()
3526 int select_nohz_load_balancer(int stop_tick
)
3528 int cpu
= smp_processor_id();
3531 cpu_set(cpu
, nohz
.cpu_mask
);
3532 cpu_rq(cpu
)->in_nohz_recently
= 1;
3535 * If we are going offline and still the leader, give up!
3537 if (cpu_is_offline(cpu
) &&
3538 atomic_read(&nohz
.load_balancer
) == cpu
) {
3539 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3544 /* time for ilb owner also to sleep */
3545 if (cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3546 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3547 atomic_set(&nohz
.load_balancer
, -1);
3551 if (atomic_read(&nohz
.load_balancer
) == -1) {
3552 /* make me the ilb owner */
3553 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
3555 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
3558 if (!cpu_isset(cpu
, nohz
.cpu_mask
))
3561 cpu_clear(cpu
, nohz
.cpu_mask
);
3563 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3564 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3571 static DEFINE_SPINLOCK(balancing
);
3574 * It checks each scheduling domain to see if it is due to be balanced,
3575 * and initiates a balancing operation if so.
3577 * Balancing parameters are set up in arch_init_sched_domains.
3579 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
3582 struct rq
*rq
= cpu_rq(cpu
);
3583 unsigned long interval
;
3584 struct sched_domain
*sd
;
3585 /* Earliest time when we have to do rebalance again */
3586 unsigned long next_balance
= jiffies
+ 60*HZ
;
3587 int update_next_balance
= 0;
3590 for_each_domain(cpu
, sd
) {
3591 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3594 interval
= sd
->balance_interval
;
3595 if (idle
!= CPU_IDLE
)
3596 interval
*= sd
->busy_factor
;
3598 /* scale ms to jiffies */
3599 interval
= msecs_to_jiffies(interval
);
3600 if (unlikely(!interval
))
3602 if (interval
> HZ
*NR_CPUS
/10)
3603 interval
= HZ
*NR_CPUS
/10;
3606 if (sd
->flags
& SD_SERIALIZE
) {
3607 if (!spin_trylock(&balancing
))
3611 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
3612 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, &tmp
)) {
3614 * We've pulled tasks over so either we're no
3615 * longer idle, or one of our SMT siblings is
3618 idle
= CPU_NOT_IDLE
;
3620 sd
->last_balance
= jiffies
;
3622 if (sd
->flags
& SD_SERIALIZE
)
3623 spin_unlock(&balancing
);
3625 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
3626 next_balance
= sd
->last_balance
+ interval
;
3627 update_next_balance
= 1;
3631 * Stop the load balance at this level. There is another
3632 * CPU in our sched group which is doing load balancing more
3640 * next_balance will be updated only when there is a need.
3641 * When the cpu is attached to null domain for ex, it will not be
3644 if (likely(update_next_balance
))
3645 rq
->next_balance
= next_balance
;
3649 * run_rebalance_domains is triggered when needed from the scheduler tick.
3650 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3651 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3653 static void run_rebalance_domains(struct softirq_action
*h
)
3655 int this_cpu
= smp_processor_id();
3656 struct rq
*this_rq
= cpu_rq(this_cpu
);
3657 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
3658 CPU_IDLE
: CPU_NOT_IDLE
;
3660 rebalance_domains(this_cpu
, idle
);
3664 * If this cpu is the owner for idle load balancing, then do the
3665 * balancing on behalf of the other idle cpus whose ticks are
3668 if (this_rq
->idle_at_tick
&&
3669 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
3670 cpumask_t cpus
= nohz
.cpu_mask
;
3674 cpu_clear(this_cpu
, cpus
);
3675 for_each_cpu_mask(balance_cpu
, cpus
) {
3677 * If this cpu gets work to do, stop the load balancing
3678 * work being done for other cpus. Next load
3679 * balancing owner will pick it up.
3684 rebalance_domains(balance_cpu
, CPU_IDLE
);
3686 rq
= cpu_rq(balance_cpu
);
3687 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
3688 this_rq
->next_balance
= rq
->next_balance
;
3695 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3697 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3698 * idle load balancing owner or decide to stop the periodic load balancing,
3699 * if the whole system is idle.
3701 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
3705 * If we were in the nohz mode recently and busy at the current
3706 * scheduler tick, then check if we need to nominate new idle
3709 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
3710 rq
->in_nohz_recently
= 0;
3712 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
3713 cpu_clear(cpu
, nohz
.cpu_mask
);
3714 atomic_set(&nohz
.load_balancer
, -1);
3717 if (atomic_read(&nohz
.load_balancer
) == -1) {
3719 * simple selection for now: Nominate the
3720 * first cpu in the nohz list to be the next
3723 * TBD: Traverse the sched domains and nominate
3724 * the nearest cpu in the nohz.cpu_mask.
3726 int ilb
= first_cpu(nohz
.cpu_mask
);
3728 if (ilb
< nr_cpu_ids
)
3734 * If this cpu is idle and doing idle load balancing for all the
3735 * cpus with ticks stopped, is it time for that to stop?
3737 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
3738 cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3744 * If this cpu is idle and the idle load balancing is done by
3745 * someone else, then no need raise the SCHED_SOFTIRQ
3747 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
3748 cpu_isset(cpu
, nohz
.cpu_mask
))
3751 if (time_after_eq(jiffies
, rq
->next_balance
))
3752 raise_softirq(SCHED_SOFTIRQ
);
3755 #else /* CONFIG_SMP */
3758 * on UP we do not need to balance between CPUs:
3760 static inline void idle_balance(int cpu
, struct rq
*rq
)
3766 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3768 EXPORT_PER_CPU_SYMBOL(kstat
);
3771 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3772 * that have not yet been banked in case the task is currently running.
3774 unsigned long long task_sched_runtime(struct task_struct
*p
)
3776 unsigned long flags
;
3780 rq
= task_rq_lock(p
, &flags
);
3781 ns
= p
->se
.sum_exec_runtime
;
3782 if (task_current(rq
, p
)) {
3783 update_rq_clock(rq
);
3784 delta_exec
= rq
->clock
- p
->se
.exec_start
;
3785 if ((s64
)delta_exec
> 0)
3788 task_rq_unlock(rq
, &flags
);
3794 * Account user cpu time to a process.
3795 * @p: the process that the cpu time gets accounted to
3796 * @cputime: the cpu time spent in user space since the last update
3798 void account_user_time(struct task_struct
*p
, cputime_t cputime
)
3800 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3803 p
->utime
= cputime_add(p
->utime
, cputime
);
3805 /* Add user time to cpustat. */
3806 tmp
= cputime_to_cputime64(cputime
);
3807 if (TASK_NICE(p
) > 0)
3808 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3810 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3814 * Account guest cpu time to a process.
3815 * @p: the process that the cpu time gets accounted to
3816 * @cputime: the cpu time spent in virtual machine since the last update
3818 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
)
3821 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3823 tmp
= cputime_to_cputime64(cputime
);
3825 p
->utime
= cputime_add(p
->utime
, cputime
);
3826 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3828 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3829 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3833 * Account scaled user cpu time to a process.
3834 * @p: the process that the cpu time gets accounted to
3835 * @cputime: the cpu time spent in user space since the last update
3837 void account_user_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3839 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime
);
3843 * Account system cpu time to a process.
3844 * @p: the process that the cpu time gets accounted to
3845 * @hardirq_offset: the offset to subtract from hardirq_count()
3846 * @cputime: the cpu time spent in kernel space since the last update
3848 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3851 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3852 struct rq
*rq
= this_rq();
3855 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0))
3856 return account_guest_time(p
, cputime
);
3858 p
->stime
= cputime_add(p
->stime
, cputime
);
3860 /* Add system time to cpustat. */
3861 tmp
= cputime_to_cputime64(cputime
);
3862 if (hardirq_count() - hardirq_offset
)
3863 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3864 else if (softirq_count())
3865 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3866 else if (p
!= rq
->idle
)
3867 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3868 else if (atomic_read(&rq
->nr_iowait
) > 0)
3869 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3871 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3872 /* Account for system time used */
3873 acct_update_integrals(p
);
3877 * Account scaled system cpu time to a process.
3878 * @p: the process that the cpu time gets accounted to
3879 * @hardirq_offset: the offset to subtract from hardirq_count()
3880 * @cputime: the cpu time spent in kernel space since the last update
3882 void account_system_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3884 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime
);
3888 * Account for involuntary wait time.
3889 * @p: the process from which the cpu time has been stolen
3890 * @steal: the cpu time spent in involuntary wait
3892 void account_steal_time(struct task_struct
*p
, cputime_t steal
)
3894 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3895 cputime64_t tmp
= cputime_to_cputime64(steal
);
3896 struct rq
*rq
= this_rq();
3898 if (p
== rq
->idle
) {
3899 p
->stime
= cputime_add(p
->stime
, steal
);
3900 if (atomic_read(&rq
->nr_iowait
) > 0)
3901 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3903 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3905 cpustat
->steal
= cputime64_add(cpustat
->steal
, tmp
);
3909 * This function gets called by the timer code, with HZ frequency.
3910 * We call it with interrupts disabled.
3912 * It also gets called by the fork code, when changing the parent's
3915 void scheduler_tick(void)
3917 int cpu
= smp_processor_id();
3918 struct rq
*rq
= cpu_rq(cpu
);
3919 struct task_struct
*curr
= rq
->curr
;
3920 u64 next_tick
= rq
->tick_timestamp
+ TICK_NSEC
;
3922 spin_lock(&rq
->lock
);
3923 __update_rq_clock(rq
);
3925 * Let rq->clock advance by at least TICK_NSEC:
3927 if (unlikely(rq
->clock
< next_tick
)) {
3928 rq
->clock
= next_tick
;
3929 rq
->clock_underflows
++;
3931 rq
->tick_timestamp
= rq
->clock
;
3932 update_last_tick_seen(rq
);
3933 update_cpu_load(rq
);
3934 curr
->sched_class
->task_tick(rq
, curr
, 0);
3935 spin_unlock(&rq
->lock
);
3938 rq
->idle_at_tick
= idle_cpu(cpu
);
3939 trigger_load_balance(rq
, cpu
);
3943 #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
3945 void __kprobes
add_preempt_count(int val
)
3950 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3952 preempt_count() += val
;
3954 * Spinlock count overflowing soon?
3956 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3959 EXPORT_SYMBOL(add_preempt_count
);
3961 void __kprobes
sub_preempt_count(int val
)
3966 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3969 * Is the spinlock portion underflowing?
3971 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3972 !(preempt_count() & PREEMPT_MASK
)))
3975 preempt_count() -= val
;
3977 EXPORT_SYMBOL(sub_preempt_count
);
3982 * Print scheduling while atomic bug:
3984 static noinline
void __schedule_bug(struct task_struct
*prev
)
3986 struct pt_regs
*regs
= get_irq_regs();
3988 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3989 prev
->comm
, prev
->pid
, preempt_count());
3991 debug_show_held_locks(prev
);
3992 if (irqs_disabled())
3993 print_irqtrace_events(prev
);
4002 * Various schedule()-time debugging checks and statistics:
4004 static inline void schedule_debug(struct task_struct
*prev
)
4007 * Test if we are atomic. Since do_exit() needs to call into
4008 * schedule() atomically, we ignore that path for now.
4009 * Otherwise, whine if we are scheduling when we should not be.
4011 if (unlikely(in_atomic_preempt_off()) && unlikely(!prev
->exit_state
))
4012 __schedule_bug(prev
);
4014 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4016 schedstat_inc(this_rq(), sched_count
);
4017 #ifdef CONFIG_SCHEDSTATS
4018 if (unlikely(prev
->lock_depth
>= 0)) {
4019 schedstat_inc(this_rq(), bkl_count
);
4020 schedstat_inc(prev
, sched_info
.bkl_count
);
4026 * Pick up the highest-prio task:
4028 static inline struct task_struct
*
4029 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4031 const struct sched_class
*class;
4032 struct task_struct
*p
;
4035 * Optimization: we know that if all tasks are in
4036 * the fair class we can call that function directly:
4038 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4039 p
= fair_sched_class
.pick_next_task(rq
);
4044 class = sched_class_highest
;
4046 p
= class->pick_next_task(rq
);
4050 * Will never be NULL as the idle class always
4051 * returns a non-NULL p:
4053 class = class->next
;
4058 * schedule() is the main scheduler function.
4060 asmlinkage
void __sched
schedule(void)
4062 struct task_struct
*prev
, *next
;
4063 unsigned long *switch_count
;
4069 cpu
= smp_processor_id();
4073 switch_count
= &prev
->nivcsw
;
4075 release_kernel_lock(prev
);
4076 need_resched_nonpreemptible
:
4078 schedule_debug(prev
);
4083 * Do the rq-clock update outside the rq lock:
4085 local_irq_disable();
4086 __update_rq_clock(rq
);
4087 spin_lock(&rq
->lock
);
4088 clear_tsk_need_resched(prev
);
4090 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4091 if (unlikely((prev
->state
& TASK_INTERRUPTIBLE
) &&
4092 signal_pending(prev
))) {
4093 prev
->state
= TASK_RUNNING
;
4095 deactivate_task(rq
, prev
, 1);
4097 switch_count
= &prev
->nvcsw
;
4101 if (prev
->sched_class
->pre_schedule
)
4102 prev
->sched_class
->pre_schedule(rq
, prev
);
4105 if (unlikely(!rq
->nr_running
))
4106 idle_balance(cpu
, rq
);
4108 prev
->sched_class
->put_prev_task(rq
, prev
);
4109 next
= pick_next_task(rq
, prev
);
4111 sched_info_switch(prev
, next
);
4113 if (likely(prev
!= next
)) {
4118 context_switch(rq
, prev
, next
); /* unlocks the rq */
4120 * the context switch might have flipped the stack from under
4121 * us, hence refresh the local variables.
4123 cpu
= smp_processor_id();
4126 spin_unlock_irq(&rq
->lock
);
4130 if (unlikely(reacquire_kernel_lock(current
) < 0))
4131 goto need_resched_nonpreemptible
;
4133 preempt_enable_no_resched();
4134 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4137 EXPORT_SYMBOL(schedule
);
4139 #ifdef CONFIG_PREEMPT
4141 * this is the entry point to schedule() from in-kernel preemption
4142 * off of preempt_enable. Kernel preemptions off return from interrupt
4143 * occur there and call schedule directly.
4145 asmlinkage
void __sched
preempt_schedule(void)
4147 struct thread_info
*ti
= current_thread_info();
4148 struct task_struct
*task
= current
;
4149 int saved_lock_depth
;
4152 * If there is a non-zero preempt_count or interrupts are disabled,
4153 * we do not want to preempt the current task. Just return..
4155 if (likely(ti
->preempt_count
|| irqs_disabled()))
4159 add_preempt_count(PREEMPT_ACTIVE
);
4162 * We keep the big kernel semaphore locked, but we
4163 * clear ->lock_depth so that schedule() doesnt
4164 * auto-release the semaphore:
4166 saved_lock_depth
= task
->lock_depth
;
4167 task
->lock_depth
= -1;
4169 task
->lock_depth
= saved_lock_depth
;
4170 sub_preempt_count(PREEMPT_ACTIVE
);
4173 * Check again in case we missed a preemption opportunity
4174 * between schedule and now.
4177 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4179 EXPORT_SYMBOL(preempt_schedule
);
4182 * this is the entry point to schedule() from kernel preemption
4183 * off of irq context.
4184 * Note, that this is called and return with irqs disabled. This will
4185 * protect us against recursive calling from irq.
4187 asmlinkage
void __sched
preempt_schedule_irq(void)
4189 struct thread_info
*ti
= current_thread_info();
4190 struct task_struct
*task
= current
;
4191 int saved_lock_depth
;
4193 /* Catch callers which need to be fixed */
4194 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4197 add_preempt_count(PREEMPT_ACTIVE
);
4200 * We keep the big kernel semaphore locked, but we
4201 * clear ->lock_depth so that schedule() doesnt
4202 * auto-release the semaphore:
4204 saved_lock_depth
= task
->lock_depth
;
4205 task
->lock_depth
= -1;
4208 local_irq_disable();
4209 task
->lock_depth
= saved_lock_depth
;
4210 sub_preempt_count(PREEMPT_ACTIVE
);
4213 * Check again in case we missed a preemption opportunity
4214 * between schedule and now.
4217 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4220 #endif /* CONFIG_PREEMPT */
4222 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4225 return try_to_wake_up(curr
->private, mode
, sync
);
4227 EXPORT_SYMBOL(default_wake_function
);
4230 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4231 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4232 * number) then we wake all the non-exclusive tasks and one exclusive task.
4234 * There are circumstances in which we can try to wake a task which has already
4235 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4236 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4238 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4239 int nr_exclusive
, int sync
, void *key
)
4241 wait_queue_t
*curr
, *next
;
4243 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4244 unsigned flags
= curr
->flags
;
4246 if (curr
->func(curr
, mode
, sync
, key
) &&
4247 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4253 * __wake_up - wake up threads blocked on a waitqueue.
4255 * @mode: which threads
4256 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4257 * @key: is directly passed to the wakeup function
4259 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4260 int nr_exclusive
, void *key
)
4262 unsigned long flags
;
4264 spin_lock_irqsave(&q
->lock
, flags
);
4265 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4266 spin_unlock_irqrestore(&q
->lock
, flags
);
4268 EXPORT_SYMBOL(__wake_up
);
4271 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4273 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4275 __wake_up_common(q
, mode
, 1, 0, NULL
);
4279 * __wake_up_sync - wake up threads blocked on a waitqueue.
4281 * @mode: which threads
4282 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4284 * The sync wakeup differs that the waker knows that it will schedule
4285 * away soon, so while the target thread will be woken up, it will not
4286 * be migrated to another CPU - ie. the two threads are 'synchronized'
4287 * with each other. This can prevent needless bouncing between CPUs.
4289 * On UP it can prevent extra preemption.
4292 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4294 unsigned long flags
;
4300 if (unlikely(!nr_exclusive
))
4303 spin_lock_irqsave(&q
->lock
, flags
);
4304 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4305 spin_unlock_irqrestore(&q
->lock
, flags
);
4307 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4309 void complete(struct completion
*x
)
4311 unsigned long flags
;
4313 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4315 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4316 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4318 EXPORT_SYMBOL(complete
);
4320 void complete_all(struct completion
*x
)
4322 unsigned long flags
;
4324 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4325 x
->done
+= UINT_MAX
/2;
4326 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4327 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4329 EXPORT_SYMBOL(complete_all
);
4331 static inline long __sched
4332 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4335 DECLARE_WAITQUEUE(wait
, current
);
4337 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4338 __add_wait_queue_tail(&x
->wait
, &wait
);
4340 if ((state
== TASK_INTERRUPTIBLE
&&
4341 signal_pending(current
)) ||
4342 (state
== TASK_KILLABLE
&&
4343 fatal_signal_pending(current
))) {
4344 __remove_wait_queue(&x
->wait
, &wait
);
4345 return -ERESTARTSYS
;
4347 __set_current_state(state
);
4348 spin_unlock_irq(&x
->wait
.lock
);
4349 timeout
= schedule_timeout(timeout
);
4350 spin_lock_irq(&x
->wait
.lock
);
4352 __remove_wait_queue(&x
->wait
, &wait
);
4356 __remove_wait_queue(&x
->wait
, &wait
);
4363 wait_for_common(struct completion
*x
, long timeout
, int state
)
4367 spin_lock_irq(&x
->wait
.lock
);
4368 timeout
= do_wait_for_common(x
, timeout
, state
);
4369 spin_unlock_irq(&x
->wait
.lock
);
4373 void __sched
wait_for_completion(struct completion
*x
)
4375 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4377 EXPORT_SYMBOL(wait_for_completion
);
4379 unsigned long __sched
4380 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4382 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4384 EXPORT_SYMBOL(wait_for_completion_timeout
);
4386 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4388 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4389 if (t
== -ERESTARTSYS
)
4393 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4395 unsigned long __sched
4396 wait_for_completion_interruptible_timeout(struct completion
*x
,
4397 unsigned long timeout
)
4399 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4401 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4403 int __sched
wait_for_completion_killable(struct completion
*x
)
4405 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4406 if (t
== -ERESTARTSYS
)
4410 EXPORT_SYMBOL(wait_for_completion_killable
);
4413 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4415 unsigned long flags
;
4418 init_waitqueue_entry(&wait
, current
);
4420 __set_current_state(state
);
4422 spin_lock_irqsave(&q
->lock
, flags
);
4423 __add_wait_queue(q
, &wait
);
4424 spin_unlock(&q
->lock
);
4425 timeout
= schedule_timeout(timeout
);
4426 spin_lock_irq(&q
->lock
);
4427 __remove_wait_queue(q
, &wait
);
4428 spin_unlock_irqrestore(&q
->lock
, flags
);
4433 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4435 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4437 EXPORT_SYMBOL(interruptible_sleep_on
);
4440 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4442 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4444 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4446 void __sched
sleep_on(wait_queue_head_t
*q
)
4448 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4450 EXPORT_SYMBOL(sleep_on
);
4452 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4454 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4456 EXPORT_SYMBOL(sleep_on_timeout
);
4458 #ifdef CONFIG_RT_MUTEXES
4461 * rt_mutex_setprio - set the current priority of a task
4463 * @prio: prio value (kernel-internal form)
4465 * This function changes the 'effective' priority of a task. It does
4466 * not touch ->normal_prio like __setscheduler().
4468 * Used by the rt_mutex code to implement priority inheritance logic.
4470 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4472 unsigned long flags
;
4473 int oldprio
, on_rq
, running
;
4475 const struct sched_class
*prev_class
= p
->sched_class
;
4477 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4479 rq
= task_rq_lock(p
, &flags
);
4480 update_rq_clock(rq
);
4483 on_rq
= p
->se
.on_rq
;
4484 running
= task_current(rq
, p
);
4486 dequeue_task(rq
, p
, 0);
4488 p
->sched_class
->put_prev_task(rq
, p
);
4491 p
->sched_class
= &rt_sched_class
;
4493 p
->sched_class
= &fair_sched_class
;
4498 p
->sched_class
->set_curr_task(rq
);
4500 enqueue_task(rq
, p
, 0);
4502 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4504 task_rq_unlock(rq
, &flags
);
4509 void set_user_nice(struct task_struct
*p
, long nice
)
4511 int old_prio
, delta
, on_rq
;
4512 unsigned long flags
;
4515 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4518 * We have to be careful, if called from sys_setpriority(),
4519 * the task might be in the middle of scheduling on another CPU.
4521 rq
= task_rq_lock(p
, &flags
);
4522 update_rq_clock(rq
);
4524 * The RT priorities are set via sched_setscheduler(), but we still
4525 * allow the 'normal' nice value to be set - but as expected
4526 * it wont have any effect on scheduling until the task is
4527 * SCHED_FIFO/SCHED_RR:
4529 if (task_has_rt_policy(p
)) {
4530 p
->static_prio
= NICE_TO_PRIO(nice
);
4533 on_rq
= p
->se
.on_rq
;
4535 dequeue_task(rq
, p
, 0);
4539 p
->static_prio
= NICE_TO_PRIO(nice
);
4542 p
->prio
= effective_prio(p
);
4543 delta
= p
->prio
- old_prio
;
4546 enqueue_task(rq
, p
, 0);
4549 * If the task increased its priority or is running and
4550 * lowered its priority, then reschedule its CPU:
4552 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4553 resched_task(rq
->curr
);
4556 task_rq_unlock(rq
, &flags
);
4558 EXPORT_SYMBOL(set_user_nice
);
4561 * can_nice - check if a task can reduce its nice value
4565 int can_nice(const struct task_struct
*p
, const int nice
)
4567 /* convert nice value [19,-20] to rlimit style value [1,40] */
4568 int nice_rlim
= 20 - nice
;
4570 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
4571 capable(CAP_SYS_NICE
));
4574 #ifdef __ARCH_WANT_SYS_NICE
4577 * sys_nice - change the priority of the current process.
4578 * @increment: priority increment
4580 * sys_setpriority is a more generic, but much slower function that
4581 * does similar things.
4583 asmlinkage
long sys_nice(int increment
)
4588 * Setpriority might change our priority at the same moment.
4589 * We don't have to worry. Conceptually one call occurs first
4590 * and we have a single winner.
4592 if (increment
< -40)
4597 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
4603 if (increment
< 0 && !can_nice(current
, nice
))
4606 retval
= security_task_setnice(current
, nice
);
4610 set_user_nice(current
, nice
);
4617 * task_prio - return the priority value of a given task.
4618 * @p: the task in question.
4620 * This is the priority value as seen by users in /proc.
4621 * RT tasks are offset by -200. Normal tasks are centered
4622 * around 0, value goes from -16 to +15.
4624 int task_prio(const struct task_struct
*p
)
4626 return p
->prio
- MAX_RT_PRIO
;
4630 * task_nice - return the nice value of a given task.
4631 * @p: the task in question.
4633 int task_nice(const struct task_struct
*p
)
4635 return TASK_NICE(p
);
4637 EXPORT_SYMBOL(task_nice
);
4640 * idle_cpu - is a given cpu idle currently?
4641 * @cpu: the processor in question.
4643 int idle_cpu(int cpu
)
4645 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4649 * idle_task - return the idle task for a given cpu.
4650 * @cpu: the processor in question.
4652 struct task_struct
*idle_task(int cpu
)
4654 return cpu_rq(cpu
)->idle
;
4658 * find_process_by_pid - find a process with a matching PID value.
4659 * @pid: the pid in question.
4661 static struct task_struct
*find_process_by_pid(pid_t pid
)
4663 return pid
? find_task_by_vpid(pid
) : current
;
4666 /* Actually do priority change: must hold rq lock. */
4668 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4670 BUG_ON(p
->se
.on_rq
);
4673 switch (p
->policy
) {
4677 p
->sched_class
= &fair_sched_class
;
4681 p
->sched_class
= &rt_sched_class
;
4685 p
->rt_priority
= prio
;
4686 p
->normal_prio
= normal_prio(p
);
4687 /* we are holding p->pi_lock already */
4688 p
->prio
= rt_mutex_getprio(p
);
4693 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4694 * @p: the task in question.
4695 * @policy: new policy.
4696 * @param: structure containing the new RT priority.
4698 * NOTE that the task may be already dead.
4700 int sched_setscheduler(struct task_struct
*p
, int policy
,
4701 struct sched_param
*param
)
4703 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4704 unsigned long flags
;
4705 const struct sched_class
*prev_class
= p
->sched_class
;
4708 /* may grab non-irq protected spin_locks */
4709 BUG_ON(in_interrupt());
4711 /* double check policy once rq lock held */
4713 policy
= oldpolicy
= p
->policy
;
4714 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4715 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4716 policy
!= SCHED_IDLE
)
4719 * Valid priorities for SCHED_FIFO and SCHED_RR are
4720 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4721 * SCHED_BATCH and SCHED_IDLE is 0.
4723 if (param
->sched_priority
< 0 ||
4724 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4725 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4727 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4731 * Allow unprivileged RT tasks to decrease priority:
4733 if (!capable(CAP_SYS_NICE
)) {
4734 if (rt_policy(policy
)) {
4735 unsigned long rlim_rtprio
;
4737 if (!lock_task_sighand(p
, &flags
))
4739 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
4740 unlock_task_sighand(p
, &flags
);
4742 /* can't set/change the rt policy */
4743 if (policy
!= p
->policy
&& !rlim_rtprio
)
4746 /* can't increase priority */
4747 if (param
->sched_priority
> p
->rt_priority
&&
4748 param
->sched_priority
> rlim_rtprio
)
4752 * Like positive nice levels, dont allow tasks to
4753 * move out of SCHED_IDLE either:
4755 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4758 /* can't change other user's priorities */
4759 if ((current
->euid
!= p
->euid
) &&
4760 (current
->euid
!= p
->uid
))
4764 #ifdef CONFIG_RT_GROUP_SCHED
4766 * Do not allow realtime tasks into groups that have no runtime
4769 if (rt_policy(policy
) && task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
4773 retval
= security_task_setscheduler(p
, policy
, param
);
4777 * make sure no PI-waiters arrive (or leave) while we are
4778 * changing the priority of the task:
4780 spin_lock_irqsave(&p
->pi_lock
, flags
);
4782 * To be able to change p->policy safely, the apropriate
4783 * runqueue lock must be held.
4785 rq
= __task_rq_lock(p
);
4786 /* recheck policy now with rq lock held */
4787 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4788 policy
= oldpolicy
= -1;
4789 __task_rq_unlock(rq
);
4790 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4793 update_rq_clock(rq
);
4794 on_rq
= p
->se
.on_rq
;
4795 running
= task_current(rq
, p
);
4797 deactivate_task(rq
, p
, 0);
4799 p
->sched_class
->put_prev_task(rq
, p
);
4802 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4805 p
->sched_class
->set_curr_task(rq
);
4807 activate_task(rq
, p
, 0);
4809 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4811 __task_rq_unlock(rq
);
4812 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4814 rt_mutex_adjust_pi(p
);
4818 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4821 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4823 struct sched_param lparam
;
4824 struct task_struct
*p
;
4827 if (!param
|| pid
< 0)
4829 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4834 p
= find_process_by_pid(pid
);
4836 retval
= sched_setscheduler(p
, policy
, &lparam
);
4843 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4844 * @pid: the pid in question.
4845 * @policy: new policy.
4846 * @param: structure containing the new RT priority.
4849 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4851 /* negative values for policy are not valid */
4855 return do_sched_setscheduler(pid
, policy
, param
);
4859 * sys_sched_setparam - set/change the RT priority of a thread
4860 * @pid: the pid in question.
4861 * @param: structure containing the new RT priority.
4863 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
4865 return do_sched_setscheduler(pid
, -1, param
);
4869 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4870 * @pid: the pid in question.
4872 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
4874 struct task_struct
*p
;
4881 read_lock(&tasklist_lock
);
4882 p
= find_process_by_pid(pid
);
4884 retval
= security_task_getscheduler(p
);
4888 read_unlock(&tasklist_lock
);
4893 * sys_sched_getscheduler - get the RT priority of a thread
4894 * @pid: the pid in question.
4895 * @param: structure containing the RT priority.
4897 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
4899 struct sched_param lp
;
4900 struct task_struct
*p
;
4903 if (!param
|| pid
< 0)
4906 read_lock(&tasklist_lock
);
4907 p
= find_process_by_pid(pid
);
4912 retval
= security_task_getscheduler(p
);
4916 lp
.sched_priority
= p
->rt_priority
;
4917 read_unlock(&tasklist_lock
);
4920 * This one might sleep, we cannot do it with a spinlock held ...
4922 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4927 read_unlock(&tasklist_lock
);
4931 long sched_setaffinity(pid_t pid
, const cpumask_t
*in_mask
)
4933 cpumask_t cpus_allowed
;
4934 cpumask_t new_mask
= *in_mask
;
4935 struct task_struct
*p
;
4939 read_lock(&tasklist_lock
);
4941 p
= find_process_by_pid(pid
);
4943 read_unlock(&tasklist_lock
);
4949 * It is not safe to call set_cpus_allowed with the
4950 * tasklist_lock held. We will bump the task_struct's
4951 * usage count and then drop tasklist_lock.
4954 read_unlock(&tasklist_lock
);
4957 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
4958 !capable(CAP_SYS_NICE
))
4961 retval
= security_task_setscheduler(p
, 0, NULL
);
4965 cpuset_cpus_allowed(p
, &cpus_allowed
);
4966 cpus_and(new_mask
, new_mask
, cpus_allowed
);
4968 retval
= set_cpus_allowed_ptr(p
, &new_mask
);
4971 cpuset_cpus_allowed(p
, &cpus_allowed
);
4972 if (!cpus_subset(new_mask
, cpus_allowed
)) {
4974 * We must have raced with a concurrent cpuset
4975 * update. Just reset the cpus_allowed to the
4976 * cpuset's cpus_allowed
4978 new_mask
= cpus_allowed
;
4988 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4989 cpumask_t
*new_mask
)
4991 if (len
< sizeof(cpumask_t
)) {
4992 memset(new_mask
, 0, sizeof(cpumask_t
));
4993 } else if (len
> sizeof(cpumask_t
)) {
4994 len
= sizeof(cpumask_t
);
4996 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5000 * sys_sched_setaffinity - set the cpu affinity of a process
5001 * @pid: pid of the process
5002 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5003 * @user_mask_ptr: user-space pointer to the new cpu mask
5005 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
5006 unsigned long __user
*user_mask_ptr
)
5011 retval
= get_user_cpu_mask(user_mask_ptr
, len
, &new_mask
);
5015 return sched_setaffinity(pid
, &new_mask
);
5019 * Represents all cpu's present in the system
5020 * In systems capable of hotplug, this map could dynamically grow
5021 * as new cpu's are detected in the system via any platform specific
5022 * method, such as ACPI for e.g.
5025 cpumask_t cpu_present_map __read_mostly
;
5026 EXPORT_SYMBOL(cpu_present_map
);
5029 cpumask_t cpu_online_map __read_mostly
= CPU_MASK_ALL
;
5030 EXPORT_SYMBOL(cpu_online_map
);
5032 cpumask_t cpu_possible_map __read_mostly
= CPU_MASK_ALL
;
5033 EXPORT_SYMBOL(cpu_possible_map
);
5036 long sched_getaffinity(pid_t pid
, cpumask_t
*mask
)
5038 struct task_struct
*p
;
5042 read_lock(&tasklist_lock
);
5045 p
= find_process_by_pid(pid
);
5049 retval
= security_task_getscheduler(p
);
5053 cpus_and(*mask
, p
->cpus_allowed
, cpu_online_map
);
5056 read_unlock(&tasklist_lock
);
5063 * sys_sched_getaffinity - get the cpu affinity of a process
5064 * @pid: pid of the process
5065 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5066 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5068 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5069 unsigned long __user
*user_mask_ptr
)
5074 if (len
< sizeof(cpumask_t
))
5077 ret
= sched_getaffinity(pid
, &mask
);
5081 if (copy_to_user(user_mask_ptr
, &mask
, sizeof(cpumask_t
)))
5084 return sizeof(cpumask_t
);
5088 * sys_sched_yield - yield the current processor to other threads.
5090 * This function yields the current CPU to other tasks. If there are no
5091 * other threads running on this CPU then this function will return.
5093 asmlinkage
long sys_sched_yield(void)
5095 struct rq
*rq
= this_rq_lock();
5097 schedstat_inc(rq
, yld_count
);
5098 current
->sched_class
->yield_task(rq
);
5101 * Since we are going to call schedule() anyway, there's
5102 * no need to preempt or enable interrupts:
5104 __release(rq
->lock
);
5105 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5106 _raw_spin_unlock(&rq
->lock
);
5107 preempt_enable_no_resched();
5114 static void __cond_resched(void)
5116 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5117 __might_sleep(__FILE__
, __LINE__
);
5120 * The BKS might be reacquired before we have dropped
5121 * PREEMPT_ACTIVE, which could trigger a second
5122 * cond_resched() call.
5125 add_preempt_count(PREEMPT_ACTIVE
);
5127 sub_preempt_count(PREEMPT_ACTIVE
);
5128 } while (need_resched());
5131 #if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY)
5132 int __sched
_cond_resched(void)
5134 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5135 system_state
== SYSTEM_RUNNING
) {
5141 EXPORT_SYMBOL(_cond_resched
);
5145 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5146 * call schedule, and on return reacquire the lock.
5148 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5149 * operations here to prevent schedule() from being called twice (once via
5150 * spin_unlock(), once by hand).
5152 int cond_resched_lock(spinlock_t
*lock
)
5154 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5157 if (spin_needbreak(lock
) || resched
) {
5159 if (resched
&& need_resched())
5168 EXPORT_SYMBOL(cond_resched_lock
);
5170 int __sched
cond_resched_softirq(void)
5172 BUG_ON(!in_softirq());
5174 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5182 EXPORT_SYMBOL(cond_resched_softirq
);
5185 * yield - yield the current processor to other threads.
5187 * This is a shortcut for kernel-space yielding - it marks the
5188 * thread runnable and calls sys_sched_yield().
5190 void __sched
yield(void)
5192 set_current_state(TASK_RUNNING
);
5195 EXPORT_SYMBOL(yield
);
5198 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5199 * that process accounting knows that this is a task in IO wait state.
5201 * But don't do that if it is a deliberate, throttling IO wait (this task
5202 * has set its backing_dev_info: the queue against which it should throttle)
5204 void __sched
io_schedule(void)
5206 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5208 delayacct_blkio_start();
5209 atomic_inc(&rq
->nr_iowait
);
5211 atomic_dec(&rq
->nr_iowait
);
5212 delayacct_blkio_end();
5214 EXPORT_SYMBOL(io_schedule
);
5216 long __sched
io_schedule_timeout(long timeout
)
5218 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5221 delayacct_blkio_start();
5222 atomic_inc(&rq
->nr_iowait
);
5223 ret
= schedule_timeout(timeout
);
5224 atomic_dec(&rq
->nr_iowait
);
5225 delayacct_blkio_end();
5230 * sys_sched_get_priority_max - return maximum RT priority.
5231 * @policy: scheduling class.
5233 * this syscall returns the maximum rt_priority that can be used
5234 * by a given scheduling class.
5236 asmlinkage
long sys_sched_get_priority_max(int policy
)
5243 ret
= MAX_USER_RT_PRIO
-1;
5255 * sys_sched_get_priority_min - return minimum RT priority.
5256 * @policy: scheduling class.
5258 * this syscall returns the minimum rt_priority that can be used
5259 * by a given scheduling class.
5261 asmlinkage
long sys_sched_get_priority_min(int policy
)
5279 * sys_sched_rr_get_interval - return the default timeslice of a process.
5280 * @pid: pid of the process.
5281 * @interval: userspace pointer to the timeslice value.
5283 * this syscall writes the default timeslice value of a given process
5284 * into the user-space timespec buffer. A value of '0' means infinity.
5287 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5289 struct task_struct
*p
;
5290 unsigned int time_slice
;
5298 read_lock(&tasklist_lock
);
5299 p
= find_process_by_pid(pid
);
5303 retval
= security_task_getscheduler(p
);
5308 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5309 * tasks that are on an otherwise idle runqueue:
5312 if (p
->policy
== SCHED_RR
) {
5313 time_slice
= DEF_TIMESLICE
;
5314 } else if (p
->policy
!= SCHED_FIFO
) {
5315 struct sched_entity
*se
= &p
->se
;
5316 unsigned long flags
;
5319 rq
= task_rq_lock(p
, &flags
);
5320 if (rq
->cfs
.load
.weight
)
5321 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5322 task_rq_unlock(rq
, &flags
);
5324 read_unlock(&tasklist_lock
);
5325 jiffies_to_timespec(time_slice
, &t
);
5326 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5330 read_unlock(&tasklist_lock
);
5334 static const char stat_nam
[] = "RSDTtZX";
5336 void sched_show_task(struct task_struct
*p
)
5338 unsigned long free
= 0;
5341 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5342 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5343 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5344 #if BITS_PER_LONG == 32
5345 if (state
== TASK_RUNNING
)
5346 printk(KERN_CONT
" running ");
5348 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5350 if (state
== TASK_RUNNING
)
5351 printk(KERN_CONT
" running task ");
5353 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5355 #ifdef CONFIG_DEBUG_STACK_USAGE
5357 unsigned long *n
= end_of_stack(p
);
5360 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
5363 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
5364 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
5366 show_stack(p
, NULL
);
5369 void show_state_filter(unsigned long state_filter
)
5371 struct task_struct
*g
, *p
;
5373 #if BITS_PER_LONG == 32
5375 " task PC stack pid father\n");
5378 " task PC stack pid father\n");
5380 read_lock(&tasklist_lock
);
5381 do_each_thread(g
, p
) {
5383 * reset the NMI-timeout, listing all files on a slow
5384 * console might take alot of time:
5386 touch_nmi_watchdog();
5387 if (!state_filter
|| (p
->state
& state_filter
))
5389 } while_each_thread(g
, p
);
5391 touch_all_softlockup_watchdogs();
5393 #ifdef CONFIG_SCHED_DEBUG
5394 sysrq_sched_debug_show();
5396 read_unlock(&tasklist_lock
);
5398 * Only show locks if all tasks are dumped:
5400 if (state_filter
== -1)
5401 debug_show_all_locks();
5404 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5406 idle
->sched_class
= &idle_sched_class
;
5410 * init_idle - set up an idle thread for a given CPU
5411 * @idle: task in question
5412 * @cpu: cpu the idle task belongs to
5414 * NOTE: this function does not set the idle thread's NEED_RESCHED
5415 * flag, to make booting more robust.
5417 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5419 struct rq
*rq
= cpu_rq(cpu
);
5420 unsigned long flags
;
5423 idle
->se
.exec_start
= sched_clock();
5425 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
5426 idle
->cpus_allowed
= cpumask_of_cpu(cpu
);
5427 __set_task_cpu(idle
, cpu
);
5429 spin_lock_irqsave(&rq
->lock
, flags
);
5430 rq
->curr
= rq
->idle
= idle
;
5431 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5434 spin_unlock_irqrestore(&rq
->lock
, flags
);
5436 /* Set the preempt count _outside_ the spinlocks! */
5437 task_thread_info(idle
)->preempt_count
= 0;
5440 * The idle tasks have their own, simple scheduling class:
5442 idle
->sched_class
= &idle_sched_class
;
5446 * In a system that switches off the HZ timer nohz_cpu_mask
5447 * indicates which cpus entered this state. This is used
5448 * in the rcu update to wait only for active cpus. For system
5449 * which do not switch off the HZ timer nohz_cpu_mask should
5450 * always be CPU_MASK_NONE.
5452 cpumask_t nohz_cpu_mask
= CPU_MASK_NONE
;
5455 * Increase the granularity value when there are more CPUs,
5456 * because with more CPUs the 'effective latency' as visible
5457 * to users decreases. But the relationship is not linear,
5458 * so pick a second-best guess by going with the log2 of the
5461 * This idea comes from the SD scheduler of Con Kolivas:
5463 static inline void sched_init_granularity(void)
5465 unsigned int factor
= 1 + ilog2(num_online_cpus());
5466 const unsigned long limit
= 200000000;
5468 sysctl_sched_min_granularity
*= factor
;
5469 if (sysctl_sched_min_granularity
> limit
)
5470 sysctl_sched_min_granularity
= limit
;
5472 sysctl_sched_latency
*= factor
;
5473 if (sysctl_sched_latency
> limit
)
5474 sysctl_sched_latency
= limit
;
5476 sysctl_sched_wakeup_granularity
*= factor
;
5481 * This is how migration works:
5483 * 1) we queue a struct migration_req structure in the source CPU's
5484 * runqueue and wake up that CPU's migration thread.
5485 * 2) we down() the locked semaphore => thread blocks.
5486 * 3) migration thread wakes up (implicitly it forces the migrated
5487 * thread off the CPU)
5488 * 4) it gets the migration request and checks whether the migrated
5489 * task is still in the wrong runqueue.
5490 * 5) if it's in the wrong runqueue then the migration thread removes
5491 * it and puts it into the right queue.
5492 * 6) migration thread up()s the semaphore.
5493 * 7) we wake up and the migration is done.
5497 * Change a given task's CPU affinity. Migrate the thread to a
5498 * proper CPU and schedule it away if the CPU it's executing on
5499 * is removed from the allowed bitmask.
5501 * NOTE: the caller must have a valid reference to the task, the
5502 * task must not exit() & deallocate itself prematurely. The
5503 * call is not atomic; no spinlocks may be held.
5505 int set_cpus_allowed_ptr(struct task_struct
*p
, const cpumask_t
*new_mask
)
5507 struct migration_req req
;
5508 unsigned long flags
;
5512 rq
= task_rq_lock(p
, &flags
);
5513 if (!cpus_intersects(*new_mask
, cpu_online_map
)) {
5518 if (p
->sched_class
->set_cpus_allowed
)
5519 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5521 p
->cpus_allowed
= *new_mask
;
5522 p
->rt
.nr_cpus_allowed
= cpus_weight(*new_mask
);
5525 /* Can the task run on the task's current CPU? If so, we're done */
5526 if (cpu_isset(task_cpu(p
), *new_mask
))
5529 if (migrate_task(p
, any_online_cpu(*new_mask
), &req
)) {
5530 /* Need help from migration thread: drop lock and wait. */
5531 task_rq_unlock(rq
, &flags
);
5532 wake_up_process(rq
->migration_thread
);
5533 wait_for_completion(&req
.done
);
5534 tlb_migrate_finish(p
->mm
);
5538 task_rq_unlock(rq
, &flags
);
5542 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5545 * Move (not current) task off this cpu, onto dest cpu. We're doing
5546 * this because either it can't run here any more (set_cpus_allowed()
5547 * away from this CPU, or CPU going down), or because we're
5548 * attempting to rebalance this task on exec (sched_exec).
5550 * So we race with normal scheduler movements, but that's OK, as long
5551 * as the task is no longer on this CPU.
5553 * Returns non-zero if task was successfully migrated.
5555 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5557 struct rq
*rq_dest
, *rq_src
;
5560 if (unlikely(cpu_is_offline(dest_cpu
)))
5563 rq_src
= cpu_rq(src_cpu
);
5564 rq_dest
= cpu_rq(dest_cpu
);
5566 double_rq_lock(rq_src
, rq_dest
);
5567 /* Already moved. */
5568 if (task_cpu(p
) != src_cpu
)
5570 /* Affinity changed (again). */
5571 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
))
5574 on_rq
= p
->se
.on_rq
;
5576 deactivate_task(rq_src
, p
, 0);
5578 set_task_cpu(p
, dest_cpu
);
5580 activate_task(rq_dest
, p
, 0);
5581 check_preempt_curr(rq_dest
, p
);
5585 double_rq_unlock(rq_src
, rq_dest
);
5590 * migration_thread - this is a highprio system thread that performs
5591 * thread migration by bumping thread off CPU then 'pushing' onto
5594 static int migration_thread(void *data
)
5596 int cpu
= (long)data
;
5600 BUG_ON(rq
->migration_thread
!= current
);
5602 set_current_state(TASK_INTERRUPTIBLE
);
5603 while (!kthread_should_stop()) {
5604 struct migration_req
*req
;
5605 struct list_head
*head
;
5607 spin_lock_irq(&rq
->lock
);
5609 if (cpu_is_offline(cpu
)) {
5610 spin_unlock_irq(&rq
->lock
);
5614 if (rq
->active_balance
) {
5615 active_load_balance(rq
, cpu
);
5616 rq
->active_balance
= 0;
5619 head
= &rq
->migration_queue
;
5621 if (list_empty(head
)) {
5622 spin_unlock_irq(&rq
->lock
);
5624 set_current_state(TASK_INTERRUPTIBLE
);
5627 req
= list_entry(head
->next
, struct migration_req
, list
);
5628 list_del_init(head
->next
);
5630 spin_unlock(&rq
->lock
);
5631 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
5634 complete(&req
->done
);
5636 __set_current_state(TASK_RUNNING
);
5640 /* Wait for kthread_stop */
5641 set_current_state(TASK_INTERRUPTIBLE
);
5642 while (!kthread_should_stop()) {
5644 set_current_state(TASK_INTERRUPTIBLE
);
5646 __set_current_state(TASK_RUNNING
);
5650 #ifdef CONFIG_HOTPLUG_CPU
5652 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5656 local_irq_disable();
5657 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
5663 * Figure out where task on dead CPU should go, use force if necessary.
5664 * NOTE: interrupts should be disabled by the caller
5666 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5668 unsigned long flags
;
5675 mask
= node_to_cpumask(cpu_to_node(dead_cpu
));
5676 cpus_and(mask
, mask
, p
->cpus_allowed
);
5677 dest_cpu
= any_online_cpu(mask
);
5679 /* On any allowed CPU? */
5680 if (dest_cpu
>= nr_cpu_ids
)
5681 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5683 /* No more Mr. Nice Guy. */
5684 if (dest_cpu
>= nr_cpu_ids
) {
5685 cpumask_t cpus_allowed
;
5687 cpuset_cpus_allowed_locked(p
, &cpus_allowed
);
5689 * Try to stay on the same cpuset, where the
5690 * current cpuset may be a subset of all cpus.
5691 * The cpuset_cpus_allowed_locked() variant of
5692 * cpuset_cpus_allowed() will not block. It must be
5693 * called within calls to cpuset_lock/cpuset_unlock.
5695 rq
= task_rq_lock(p
, &flags
);
5696 p
->cpus_allowed
= cpus_allowed
;
5697 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5698 task_rq_unlock(rq
, &flags
);
5701 * Don't tell them about moving exiting tasks or
5702 * kernel threads (both mm NULL), since they never
5705 if (p
->mm
&& printk_ratelimit()) {
5706 printk(KERN_INFO
"process %d (%s) no "
5707 "longer affine to cpu%d\n",
5708 task_pid_nr(p
), p
->comm
, dead_cpu
);
5711 } while (!__migrate_task_irq(p
, dead_cpu
, dest_cpu
));
5715 * While a dead CPU has no uninterruptible tasks queued at this point,
5716 * it might still have a nonzero ->nr_uninterruptible counter, because
5717 * for performance reasons the counter is not stricly tracking tasks to
5718 * their home CPUs. So we just add the counter to another CPU's counter,
5719 * to keep the global sum constant after CPU-down:
5721 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5723 struct rq
*rq_dest
= cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR
));
5724 unsigned long flags
;
5726 local_irq_save(flags
);
5727 double_rq_lock(rq_src
, rq_dest
);
5728 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5729 rq_src
->nr_uninterruptible
= 0;
5730 double_rq_unlock(rq_src
, rq_dest
);
5731 local_irq_restore(flags
);
5734 /* Run through task list and migrate tasks from the dead cpu. */
5735 static void migrate_live_tasks(int src_cpu
)
5737 struct task_struct
*p
, *t
;
5739 read_lock(&tasklist_lock
);
5741 do_each_thread(t
, p
) {
5745 if (task_cpu(p
) == src_cpu
)
5746 move_task_off_dead_cpu(src_cpu
, p
);
5747 } while_each_thread(t
, p
);
5749 read_unlock(&tasklist_lock
);
5753 * Schedules idle task to be the next runnable task on current CPU.
5754 * It does so by boosting its priority to highest possible.
5755 * Used by CPU offline code.
5757 void sched_idle_next(void)
5759 int this_cpu
= smp_processor_id();
5760 struct rq
*rq
= cpu_rq(this_cpu
);
5761 struct task_struct
*p
= rq
->idle
;
5762 unsigned long flags
;
5764 /* cpu has to be offline */
5765 BUG_ON(cpu_online(this_cpu
));
5768 * Strictly not necessary since rest of the CPUs are stopped by now
5769 * and interrupts disabled on the current cpu.
5771 spin_lock_irqsave(&rq
->lock
, flags
);
5773 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5775 update_rq_clock(rq
);
5776 activate_task(rq
, p
, 0);
5778 spin_unlock_irqrestore(&rq
->lock
, flags
);
5782 * Ensures that the idle task is using init_mm right before its cpu goes
5785 void idle_task_exit(void)
5787 struct mm_struct
*mm
= current
->active_mm
;
5789 BUG_ON(cpu_online(smp_processor_id()));
5792 switch_mm(mm
, &init_mm
, current
);
5796 /* called under rq->lock with disabled interrupts */
5797 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5799 struct rq
*rq
= cpu_rq(dead_cpu
);
5801 /* Must be exiting, otherwise would be on tasklist. */
5802 BUG_ON(!p
->exit_state
);
5804 /* Cannot have done final schedule yet: would have vanished. */
5805 BUG_ON(p
->state
== TASK_DEAD
);
5810 * Drop lock around migration; if someone else moves it,
5811 * that's OK. No task can be added to this CPU, so iteration is
5814 spin_unlock_irq(&rq
->lock
);
5815 move_task_off_dead_cpu(dead_cpu
, p
);
5816 spin_lock_irq(&rq
->lock
);
5821 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5822 static void migrate_dead_tasks(unsigned int dead_cpu
)
5824 struct rq
*rq
= cpu_rq(dead_cpu
);
5825 struct task_struct
*next
;
5828 if (!rq
->nr_running
)
5830 update_rq_clock(rq
);
5831 next
= pick_next_task(rq
, rq
->curr
);
5834 migrate_dead(dead_cpu
, next
);
5838 #endif /* CONFIG_HOTPLUG_CPU */
5840 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5842 static struct ctl_table sd_ctl_dir
[] = {
5844 .procname
= "sched_domain",
5850 static struct ctl_table sd_ctl_root
[] = {
5852 .ctl_name
= CTL_KERN
,
5853 .procname
= "kernel",
5855 .child
= sd_ctl_dir
,
5860 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5862 struct ctl_table
*entry
=
5863 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5868 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5870 struct ctl_table
*entry
;
5873 * In the intermediate directories, both the child directory and
5874 * procname are dynamically allocated and could fail but the mode
5875 * will always be set. In the lowest directory the names are
5876 * static strings and all have proc handlers.
5878 for (entry
= *tablep
; entry
->mode
; entry
++) {
5880 sd_free_ctl_entry(&entry
->child
);
5881 if (entry
->proc_handler
== NULL
)
5882 kfree(entry
->procname
);
5890 set_table_entry(struct ctl_table
*entry
,
5891 const char *procname
, void *data
, int maxlen
,
5892 mode_t mode
, proc_handler
*proc_handler
)
5894 entry
->procname
= procname
;
5896 entry
->maxlen
= maxlen
;
5898 entry
->proc_handler
= proc_handler
;
5901 static struct ctl_table
*
5902 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5904 struct ctl_table
*table
= sd_alloc_ctl_entry(12);
5909 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5910 sizeof(long), 0644, proc_doulongvec_minmax
);
5911 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5912 sizeof(long), 0644, proc_doulongvec_minmax
);
5913 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5914 sizeof(int), 0644, proc_dointvec_minmax
);
5915 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5916 sizeof(int), 0644, proc_dointvec_minmax
);
5917 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5918 sizeof(int), 0644, proc_dointvec_minmax
);
5919 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5920 sizeof(int), 0644, proc_dointvec_minmax
);
5921 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5922 sizeof(int), 0644, proc_dointvec_minmax
);
5923 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5924 sizeof(int), 0644, proc_dointvec_minmax
);
5925 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5926 sizeof(int), 0644, proc_dointvec_minmax
);
5927 set_table_entry(&table
[9], "cache_nice_tries",
5928 &sd
->cache_nice_tries
,
5929 sizeof(int), 0644, proc_dointvec_minmax
);
5930 set_table_entry(&table
[10], "flags", &sd
->flags
,
5931 sizeof(int), 0644, proc_dointvec_minmax
);
5932 /* &table[11] is terminator */
5937 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5939 struct ctl_table
*entry
, *table
;
5940 struct sched_domain
*sd
;
5941 int domain_num
= 0, i
;
5944 for_each_domain(cpu
, sd
)
5946 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5951 for_each_domain(cpu
, sd
) {
5952 snprintf(buf
, 32, "domain%d", i
);
5953 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5955 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5962 static struct ctl_table_header
*sd_sysctl_header
;
5963 static void register_sched_domain_sysctl(void)
5965 int i
, cpu_num
= num_online_cpus();
5966 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5969 WARN_ON(sd_ctl_dir
[0].child
);
5970 sd_ctl_dir
[0].child
= entry
;
5975 for_each_online_cpu(i
) {
5976 snprintf(buf
, 32, "cpu%d", i
);
5977 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5979 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5983 WARN_ON(sd_sysctl_header
);
5984 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5987 /* may be called multiple times per register */
5988 static void unregister_sched_domain_sysctl(void)
5990 if (sd_sysctl_header
)
5991 unregister_sysctl_table(sd_sysctl_header
);
5992 sd_sysctl_header
= NULL
;
5993 if (sd_ctl_dir
[0].child
)
5994 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5997 static void register_sched_domain_sysctl(void)
6000 static void unregister_sched_domain_sysctl(void)
6006 * migration_call - callback that gets triggered when a CPU is added.
6007 * Here we can start up the necessary migration thread for the new CPU.
6009 static int __cpuinit
6010 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6012 struct task_struct
*p
;
6013 int cpu
= (long)hcpu
;
6014 unsigned long flags
;
6019 case CPU_UP_PREPARE
:
6020 case CPU_UP_PREPARE_FROZEN
:
6021 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6024 kthread_bind(p
, cpu
);
6025 /* Must be high prio: stop_machine expects to yield to it. */
6026 rq
= task_rq_lock(p
, &flags
);
6027 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6028 task_rq_unlock(rq
, &flags
);
6029 cpu_rq(cpu
)->migration_thread
= p
;
6033 case CPU_ONLINE_FROZEN
:
6034 /* Strictly unnecessary, as first user will wake it. */
6035 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6037 /* Update our root-domain */
6039 spin_lock_irqsave(&rq
->lock
, flags
);
6041 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6042 cpu_set(cpu
, rq
->rd
->online
);
6044 spin_unlock_irqrestore(&rq
->lock
, flags
);
6047 #ifdef CONFIG_HOTPLUG_CPU
6048 case CPU_UP_CANCELED
:
6049 case CPU_UP_CANCELED_FROZEN
:
6050 if (!cpu_rq(cpu
)->migration_thread
)
6052 /* Unbind it from offline cpu so it can run. Fall thru. */
6053 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6054 any_online_cpu(cpu_online_map
));
6055 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6056 cpu_rq(cpu
)->migration_thread
= NULL
;
6060 case CPU_DEAD_FROZEN
:
6061 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6062 migrate_live_tasks(cpu
);
6064 kthread_stop(rq
->migration_thread
);
6065 rq
->migration_thread
= NULL
;
6066 /* Idle task back to normal (off runqueue, low prio) */
6067 spin_lock_irq(&rq
->lock
);
6068 update_rq_clock(rq
);
6069 deactivate_task(rq
, rq
->idle
, 0);
6070 rq
->idle
->static_prio
= MAX_PRIO
;
6071 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6072 rq
->idle
->sched_class
= &idle_sched_class
;
6073 migrate_dead_tasks(cpu
);
6074 spin_unlock_irq(&rq
->lock
);
6076 migrate_nr_uninterruptible(rq
);
6077 BUG_ON(rq
->nr_running
!= 0);
6080 * No need to migrate the tasks: it was best-effort if
6081 * they didn't take sched_hotcpu_mutex. Just wake up
6084 spin_lock_irq(&rq
->lock
);
6085 while (!list_empty(&rq
->migration_queue
)) {
6086 struct migration_req
*req
;
6088 req
= list_entry(rq
->migration_queue
.next
,
6089 struct migration_req
, list
);
6090 list_del_init(&req
->list
);
6091 complete(&req
->done
);
6093 spin_unlock_irq(&rq
->lock
);
6097 case CPU_DYING_FROZEN
:
6098 /* Update our root-domain */
6100 spin_lock_irqsave(&rq
->lock
, flags
);
6102 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6103 cpu_clear(cpu
, rq
->rd
->online
);
6105 spin_unlock_irqrestore(&rq
->lock
, flags
);
6112 /* Register at highest priority so that task migration (migrate_all_tasks)
6113 * happens before everything else.
6115 static struct notifier_block __cpuinitdata migration_notifier
= {
6116 .notifier_call
= migration_call
,
6120 void __init
migration_init(void)
6122 void *cpu
= (void *)(long)smp_processor_id();
6125 /* Start one for the boot CPU: */
6126 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6127 BUG_ON(err
== NOTIFY_BAD
);
6128 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6129 register_cpu_notifier(&migration_notifier
);
6135 #ifdef CONFIG_SCHED_DEBUG
6137 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6138 cpumask_t
*groupmask
)
6140 struct sched_group
*group
= sd
->groups
;
6143 cpulist_scnprintf(str
, sizeof(str
), sd
->span
);
6144 cpus_clear(*groupmask
);
6146 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6148 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6149 printk("does not load-balance\n");
6151 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6156 printk(KERN_CONT
"span %s\n", str
);
6158 if (!cpu_isset(cpu
, sd
->span
)) {
6159 printk(KERN_ERR
"ERROR: domain->span does not contain "
6162 if (!cpu_isset(cpu
, group
->cpumask
)) {
6163 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6167 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6171 printk(KERN_ERR
"ERROR: group is NULL\n");
6175 if (!group
->__cpu_power
) {
6176 printk(KERN_CONT
"\n");
6177 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6182 if (!cpus_weight(group
->cpumask
)) {
6183 printk(KERN_CONT
"\n");
6184 printk(KERN_ERR
"ERROR: empty group\n");
6188 if (cpus_intersects(*groupmask
, group
->cpumask
)) {
6189 printk(KERN_CONT
"\n");
6190 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6194 cpus_or(*groupmask
, *groupmask
, group
->cpumask
);
6196 cpulist_scnprintf(str
, sizeof(str
), group
->cpumask
);
6197 printk(KERN_CONT
" %s", str
);
6199 group
= group
->next
;
6200 } while (group
!= sd
->groups
);
6201 printk(KERN_CONT
"\n");
6203 if (!cpus_equal(sd
->span
, *groupmask
))
6204 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6206 if (sd
->parent
&& !cpus_subset(*groupmask
, sd
->parent
->span
))
6207 printk(KERN_ERR
"ERROR: parent span is not a superset "
6208 "of domain->span\n");
6212 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6214 cpumask_t
*groupmask
;
6218 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6222 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6224 groupmask
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
6226 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6231 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6241 # define sched_domain_debug(sd, cpu) do { } while (0)
6244 static int sd_degenerate(struct sched_domain
*sd
)
6246 if (cpus_weight(sd
->span
) == 1)
6249 /* Following flags need at least 2 groups */
6250 if (sd
->flags
& (SD_LOAD_BALANCE
|
6251 SD_BALANCE_NEWIDLE
|
6255 SD_SHARE_PKG_RESOURCES
)) {
6256 if (sd
->groups
!= sd
->groups
->next
)
6260 /* Following flags don't use groups */
6261 if (sd
->flags
& (SD_WAKE_IDLE
|
6270 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6272 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6274 if (sd_degenerate(parent
))
6277 if (!cpus_equal(sd
->span
, parent
->span
))
6280 /* Does parent contain flags not in child? */
6281 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6282 if (cflags
& SD_WAKE_AFFINE
)
6283 pflags
&= ~SD_WAKE_BALANCE
;
6284 /* Flags needing groups don't count if only 1 group in parent */
6285 if (parent
->groups
== parent
->groups
->next
) {
6286 pflags
&= ~(SD_LOAD_BALANCE
|
6287 SD_BALANCE_NEWIDLE
|
6291 SD_SHARE_PKG_RESOURCES
);
6293 if (~cflags
& pflags
)
6299 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6301 unsigned long flags
;
6302 const struct sched_class
*class;
6304 spin_lock_irqsave(&rq
->lock
, flags
);
6307 struct root_domain
*old_rd
= rq
->rd
;
6309 for (class = sched_class_highest
; class; class = class->next
) {
6310 if (class->leave_domain
)
6311 class->leave_domain(rq
);
6314 cpu_clear(rq
->cpu
, old_rd
->span
);
6315 cpu_clear(rq
->cpu
, old_rd
->online
);
6317 if (atomic_dec_and_test(&old_rd
->refcount
))
6321 atomic_inc(&rd
->refcount
);
6324 cpu_set(rq
->cpu
, rd
->span
);
6325 if (cpu_isset(rq
->cpu
, cpu_online_map
))
6326 cpu_set(rq
->cpu
, rd
->online
);
6328 for (class = sched_class_highest
; class; class = class->next
) {
6329 if (class->join_domain
)
6330 class->join_domain(rq
);
6333 spin_unlock_irqrestore(&rq
->lock
, flags
);
6336 static void init_rootdomain(struct root_domain
*rd
)
6338 memset(rd
, 0, sizeof(*rd
));
6340 cpus_clear(rd
->span
);
6341 cpus_clear(rd
->online
);
6344 static void init_defrootdomain(void)
6346 init_rootdomain(&def_root_domain
);
6347 atomic_set(&def_root_domain
.refcount
, 1);
6350 static struct root_domain
*alloc_rootdomain(void)
6352 struct root_domain
*rd
;
6354 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6358 init_rootdomain(rd
);
6364 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6365 * hold the hotplug lock.
6368 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6370 struct rq
*rq
= cpu_rq(cpu
);
6371 struct sched_domain
*tmp
;
6373 /* Remove the sched domains which do not contribute to scheduling. */
6374 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
) {
6375 struct sched_domain
*parent
= tmp
->parent
;
6378 if (sd_parent_degenerate(tmp
, parent
)) {
6379 tmp
->parent
= parent
->parent
;
6381 parent
->parent
->child
= tmp
;
6385 if (sd
&& sd_degenerate(sd
)) {
6391 sched_domain_debug(sd
, cpu
);
6393 rq_attach_root(rq
, rd
);
6394 rcu_assign_pointer(rq
->sd
, sd
);
6397 /* cpus with isolated domains */
6398 static cpumask_t cpu_isolated_map
= CPU_MASK_NONE
;
6400 /* Setup the mask of cpus configured for isolated domains */
6401 static int __init
isolated_cpu_setup(char *str
)
6403 int ints
[NR_CPUS
], i
;
6405 str
= get_options(str
, ARRAY_SIZE(ints
), ints
);
6406 cpus_clear(cpu_isolated_map
);
6407 for (i
= 1; i
<= ints
[0]; i
++)
6408 if (ints
[i
] < NR_CPUS
)
6409 cpu_set(ints
[i
], cpu_isolated_map
);
6413 __setup("isolcpus=", isolated_cpu_setup
);
6416 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6417 * to a function which identifies what group(along with sched group) a CPU
6418 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6419 * (due to the fact that we keep track of groups covered with a cpumask_t).
6421 * init_sched_build_groups will build a circular linked list of the groups
6422 * covered by the given span, and will set each group's ->cpumask correctly,
6423 * and ->cpu_power to 0.
6426 init_sched_build_groups(const cpumask_t
*span
, const cpumask_t
*cpu_map
,
6427 int (*group_fn
)(int cpu
, const cpumask_t
*cpu_map
,
6428 struct sched_group
**sg
,
6429 cpumask_t
*tmpmask
),
6430 cpumask_t
*covered
, cpumask_t
*tmpmask
)
6432 struct sched_group
*first
= NULL
, *last
= NULL
;
6435 cpus_clear(*covered
);
6437 for_each_cpu_mask(i
, *span
) {
6438 struct sched_group
*sg
;
6439 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6442 if (cpu_isset(i
, *covered
))
6445 cpus_clear(sg
->cpumask
);
6446 sg
->__cpu_power
= 0;
6448 for_each_cpu_mask(j
, *span
) {
6449 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6452 cpu_set(j
, *covered
);
6453 cpu_set(j
, sg
->cpumask
);
6464 #define SD_NODES_PER_DOMAIN 16
6469 * find_next_best_node - find the next node to include in a sched_domain
6470 * @node: node whose sched_domain we're building
6471 * @used_nodes: nodes already in the sched_domain
6473 * Find the next node to include in a given scheduling domain. Simply
6474 * finds the closest node not already in the @used_nodes map.
6476 * Should use nodemask_t.
6478 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6480 int i
, n
, val
, min_val
, best_node
= 0;
6484 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6485 /* Start at @node */
6486 n
= (node
+ i
) % MAX_NUMNODES
;
6488 if (!nr_cpus_node(n
))
6491 /* Skip already used nodes */
6492 if (node_isset(n
, *used_nodes
))
6495 /* Simple min distance search */
6496 val
= node_distance(node
, n
);
6498 if (val
< min_val
) {
6504 node_set(best_node
, *used_nodes
);
6509 * sched_domain_node_span - get a cpumask for a node's sched_domain
6510 * @node: node whose cpumask we're constructing
6512 * Given a node, construct a good cpumask for its sched_domain to span. It
6513 * should be one that prevents unnecessary balancing, but also spreads tasks
6516 static void sched_domain_node_span(int node
, cpumask_t
*span
)
6518 nodemask_t used_nodes
;
6519 node_to_cpumask_ptr(nodemask
, node
);
6523 nodes_clear(used_nodes
);
6525 cpus_or(*span
, *span
, *nodemask
);
6526 node_set(node
, used_nodes
);
6528 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6529 int next_node
= find_next_best_node(node
, &used_nodes
);
6531 node_to_cpumask_ptr_next(nodemask
, next_node
);
6532 cpus_or(*span
, *span
, *nodemask
);
6537 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6540 * SMT sched-domains:
6542 #ifdef CONFIG_SCHED_SMT
6543 static DEFINE_PER_CPU(struct sched_domain
, cpu_domains
);
6544 static DEFINE_PER_CPU(struct sched_group
, sched_group_cpus
);
6547 cpu_to_cpu_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6551 *sg
= &per_cpu(sched_group_cpus
, cpu
);
6557 * multi-core sched-domains:
6559 #ifdef CONFIG_SCHED_MC
6560 static DEFINE_PER_CPU(struct sched_domain
, core_domains
);
6561 static DEFINE_PER_CPU(struct sched_group
, sched_group_core
);
6564 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6566 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6571 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6572 cpus_and(*mask
, *mask
, *cpu_map
);
6573 group
= first_cpu(*mask
);
6575 *sg
= &per_cpu(sched_group_core
, group
);
6578 #elif defined(CONFIG_SCHED_MC)
6580 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6584 *sg
= &per_cpu(sched_group_core
, cpu
);
6589 static DEFINE_PER_CPU(struct sched_domain
, phys_domains
);
6590 static DEFINE_PER_CPU(struct sched_group
, sched_group_phys
);
6593 cpu_to_phys_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6597 #ifdef CONFIG_SCHED_MC
6598 *mask
= cpu_coregroup_map(cpu
);
6599 cpus_and(*mask
, *mask
, *cpu_map
);
6600 group
= first_cpu(*mask
);
6601 #elif defined(CONFIG_SCHED_SMT)
6602 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6603 cpus_and(*mask
, *mask
, *cpu_map
);
6604 group
= first_cpu(*mask
);
6609 *sg
= &per_cpu(sched_group_phys
, group
);
6615 * The init_sched_build_groups can't handle what we want to do with node
6616 * groups, so roll our own. Now each node has its own list of groups which
6617 * gets dynamically allocated.
6619 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
6620 static struct sched_group
***sched_group_nodes_bycpu
;
6622 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
6623 static DEFINE_PER_CPU(struct sched_group
, sched_group_allnodes
);
6625 static int cpu_to_allnodes_group(int cpu
, const cpumask_t
*cpu_map
,
6626 struct sched_group
**sg
, cpumask_t
*nodemask
)
6630 *nodemask
= node_to_cpumask(cpu_to_node(cpu
));
6631 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6632 group
= first_cpu(*nodemask
);
6635 *sg
= &per_cpu(sched_group_allnodes
, group
);
6639 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6641 struct sched_group
*sg
= group_head
;
6647 for_each_cpu_mask(j
, sg
->cpumask
) {
6648 struct sched_domain
*sd
;
6650 sd
= &per_cpu(phys_domains
, j
);
6651 if (j
!= first_cpu(sd
->groups
->cpumask
)) {
6653 * Only add "power" once for each
6659 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
6662 } while (sg
!= group_head
);
6667 /* Free memory allocated for various sched_group structures */
6668 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6672 for_each_cpu_mask(cpu
, *cpu_map
) {
6673 struct sched_group
**sched_group_nodes
6674 = sched_group_nodes_bycpu
[cpu
];
6676 if (!sched_group_nodes
)
6679 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6680 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6682 *nodemask
= node_to_cpumask(i
);
6683 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6684 if (cpus_empty(*nodemask
))
6694 if (oldsg
!= sched_group_nodes
[i
])
6697 kfree(sched_group_nodes
);
6698 sched_group_nodes_bycpu
[cpu
] = NULL
;
6702 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6708 * Initialize sched groups cpu_power.
6710 * cpu_power indicates the capacity of sched group, which is used while
6711 * distributing the load between different sched groups in a sched domain.
6712 * Typically cpu_power for all the groups in a sched domain will be same unless
6713 * there are asymmetries in the topology. If there are asymmetries, group
6714 * having more cpu_power will pickup more load compared to the group having
6717 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6718 * the maximum number of tasks a group can handle in the presence of other idle
6719 * or lightly loaded groups in the same sched domain.
6721 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6723 struct sched_domain
*child
;
6724 struct sched_group
*group
;
6726 WARN_ON(!sd
|| !sd
->groups
);
6728 if (cpu
!= first_cpu(sd
->groups
->cpumask
))
6733 sd
->groups
->__cpu_power
= 0;
6736 * For perf policy, if the groups in child domain share resources
6737 * (for example cores sharing some portions of the cache hierarchy
6738 * or SMT), then set this domain groups cpu_power such that each group
6739 * can handle only one task, when there are other idle groups in the
6740 * same sched domain.
6742 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
6744 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
6745 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
6750 * add cpu_power of each child group to this groups cpu_power
6752 group
= child
->groups
;
6754 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
6755 group
= group
->next
;
6756 } while (group
!= child
->groups
);
6760 * Initializers for schedule domains
6761 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6764 #define SD_INIT(sd, type) sd_init_##type(sd)
6765 #define SD_INIT_FUNC(type) \
6766 static noinline void sd_init_##type(struct sched_domain *sd) \
6768 memset(sd, 0, sizeof(*sd)); \
6769 *sd = SD_##type##_INIT; \
6774 SD_INIT_FUNC(ALLNODES
)
6777 #ifdef CONFIG_SCHED_SMT
6778 SD_INIT_FUNC(SIBLING
)
6780 #ifdef CONFIG_SCHED_MC
6785 * To minimize stack usage kmalloc room for cpumasks and share the
6786 * space as the usage in build_sched_domains() dictates. Used only
6787 * if the amount of space is significant.
6790 cpumask_t tmpmask
; /* make this one first */
6793 cpumask_t this_sibling_map
;
6794 cpumask_t this_core_map
;
6796 cpumask_t send_covered
;
6799 cpumask_t domainspan
;
6801 cpumask_t notcovered
;
6806 #define SCHED_CPUMASK_ALLOC 1
6807 #define SCHED_CPUMASK_FREE(v) kfree(v)
6808 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
6810 #define SCHED_CPUMASK_ALLOC 0
6811 #define SCHED_CPUMASK_FREE(v)
6812 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
6815 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
6816 ((unsigned long)(a) + offsetof(struct allmasks, v))
6819 * Build sched domains for a given set of cpus and attach the sched domains
6820 * to the individual cpus
6822 static int build_sched_domains(const cpumask_t
*cpu_map
)
6825 struct root_domain
*rd
;
6826 SCHED_CPUMASK_DECLARE(allmasks
);
6829 struct sched_group
**sched_group_nodes
= NULL
;
6830 int sd_allnodes
= 0;
6833 * Allocate the per-node list of sched groups
6835 sched_group_nodes
= kcalloc(MAX_NUMNODES
, sizeof(struct sched_group
*),
6837 if (!sched_group_nodes
) {
6838 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6843 rd
= alloc_rootdomain();
6845 printk(KERN_WARNING
"Cannot alloc root domain\n");
6847 kfree(sched_group_nodes
);
6852 #if SCHED_CPUMASK_ALLOC
6853 /* get space for all scratch cpumask variables */
6854 allmasks
= kmalloc(sizeof(*allmasks
), GFP_KERNEL
);
6856 printk(KERN_WARNING
"Cannot alloc cpumask array\n");
6859 kfree(sched_group_nodes
);
6864 tmpmask
= (cpumask_t
*)allmasks
;
6868 sched_group_nodes_bycpu
[first_cpu(*cpu_map
)] = sched_group_nodes
;
6872 * Set up domains for cpus specified by the cpu_map.
6874 for_each_cpu_mask(i
, *cpu_map
) {
6875 struct sched_domain
*sd
= NULL
, *p
;
6876 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6878 *nodemask
= node_to_cpumask(cpu_to_node(i
));
6879 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6882 if (cpus_weight(*cpu_map
) >
6883 SD_NODES_PER_DOMAIN
*cpus_weight(*nodemask
)) {
6884 sd
= &per_cpu(allnodes_domains
, i
);
6885 SD_INIT(sd
, ALLNODES
);
6886 sd
->span
= *cpu_map
;
6887 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6893 sd
= &per_cpu(node_domains
, i
);
6895 sched_domain_node_span(cpu_to_node(i
), &sd
->span
);
6899 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6903 sd
= &per_cpu(phys_domains
, i
);
6905 sd
->span
= *nodemask
;
6909 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6911 #ifdef CONFIG_SCHED_MC
6913 sd
= &per_cpu(core_domains
, i
);
6915 sd
->span
= cpu_coregroup_map(i
);
6916 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6919 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6922 #ifdef CONFIG_SCHED_SMT
6924 sd
= &per_cpu(cpu_domains
, i
);
6925 SD_INIT(sd
, SIBLING
);
6926 sd
->span
= per_cpu(cpu_sibling_map
, i
);
6927 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6930 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6934 #ifdef CONFIG_SCHED_SMT
6935 /* Set up CPU (sibling) groups */
6936 for_each_cpu_mask(i
, *cpu_map
) {
6937 SCHED_CPUMASK_VAR(this_sibling_map
, allmasks
);
6938 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6940 *this_sibling_map
= per_cpu(cpu_sibling_map
, i
);
6941 cpus_and(*this_sibling_map
, *this_sibling_map
, *cpu_map
);
6942 if (i
!= first_cpu(*this_sibling_map
))
6945 init_sched_build_groups(this_sibling_map
, cpu_map
,
6947 send_covered
, tmpmask
);
6951 #ifdef CONFIG_SCHED_MC
6952 /* Set up multi-core groups */
6953 for_each_cpu_mask(i
, *cpu_map
) {
6954 SCHED_CPUMASK_VAR(this_core_map
, allmasks
);
6955 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6957 *this_core_map
= cpu_coregroup_map(i
);
6958 cpus_and(*this_core_map
, *this_core_map
, *cpu_map
);
6959 if (i
!= first_cpu(*this_core_map
))
6962 init_sched_build_groups(this_core_map
, cpu_map
,
6964 send_covered
, tmpmask
);
6968 /* Set up physical groups */
6969 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6970 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6971 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6973 *nodemask
= node_to_cpumask(i
);
6974 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6975 if (cpus_empty(*nodemask
))
6978 init_sched_build_groups(nodemask
, cpu_map
,
6980 send_covered
, tmpmask
);
6984 /* Set up node groups */
6986 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6988 init_sched_build_groups(cpu_map
, cpu_map
,
6989 &cpu_to_allnodes_group
,
6990 send_covered
, tmpmask
);
6993 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6994 /* Set up node groups */
6995 struct sched_group
*sg
, *prev
;
6996 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6997 SCHED_CPUMASK_VAR(domainspan
, allmasks
);
6998 SCHED_CPUMASK_VAR(covered
, allmasks
);
7001 *nodemask
= node_to_cpumask(i
);
7002 cpus_clear(*covered
);
7004 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7005 if (cpus_empty(*nodemask
)) {
7006 sched_group_nodes
[i
] = NULL
;
7010 sched_domain_node_span(i
, domainspan
);
7011 cpus_and(*domainspan
, *domainspan
, *cpu_map
);
7013 sg
= kmalloc_node(sizeof(struct sched_group
), GFP_KERNEL
, i
);
7015 printk(KERN_WARNING
"Can not alloc domain group for "
7019 sched_group_nodes
[i
] = sg
;
7020 for_each_cpu_mask(j
, *nodemask
) {
7021 struct sched_domain
*sd
;
7023 sd
= &per_cpu(node_domains
, j
);
7026 sg
->__cpu_power
= 0;
7027 sg
->cpumask
= *nodemask
;
7029 cpus_or(*covered
, *covered
, *nodemask
);
7032 for (j
= 0; j
< MAX_NUMNODES
; j
++) {
7033 SCHED_CPUMASK_VAR(notcovered
, allmasks
);
7034 int n
= (i
+ j
) % MAX_NUMNODES
;
7035 node_to_cpumask_ptr(pnodemask
, n
);
7037 cpus_complement(*notcovered
, *covered
);
7038 cpus_and(*tmpmask
, *notcovered
, *cpu_map
);
7039 cpus_and(*tmpmask
, *tmpmask
, *domainspan
);
7040 if (cpus_empty(*tmpmask
))
7043 cpus_and(*tmpmask
, *tmpmask
, *pnodemask
);
7044 if (cpus_empty(*tmpmask
))
7047 sg
= kmalloc_node(sizeof(struct sched_group
),
7051 "Can not alloc domain group for node %d\n", j
);
7054 sg
->__cpu_power
= 0;
7055 sg
->cpumask
= *tmpmask
;
7056 sg
->next
= prev
->next
;
7057 cpus_or(*covered
, *covered
, *tmpmask
);
7064 /* Calculate CPU power for physical packages and nodes */
7065 #ifdef CONFIG_SCHED_SMT
7066 for_each_cpu_mask(i
, *cpu_map
) {
7067 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
);
7069 init_sched_groups_power(i
, sd
);
7072 #ifdef CONFIG_SCHED_MC
7073 for_each_cpu_mask(i
, *cpu_map
) {
7074 struct sched_domain
*sd
= &per_cpu(core_domains
, i
);
7076 init_sched_groups_power(i
, sd
);
7080 for_each_cpu_mask(i
, *cpu_map
) {
7081 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
);
7083 init_sched_groups_power(i
, sd
);
7087 for (i
= 0; i
< MAX_NUMNODES
; i
++)
7088 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7091 struct sched_group
*sg
;
7093 cpu_to_allnodes_group(first_cpu(*cpu_map
), cpu_map
, &sg
,
7095 init_numa_sched_groups_power(sg
);
7099 /* Attach the domains */
7100 for_each_cpu_mask(i
, *cpu_map
) {
7101 struct sched_domain
*sd
;
7102 #ifdef CONFIG_SCHED_SMT
7103 sd
= &per_cpu(cpu_domains
, i
);
7104 #elif defined(CONFIG_SCHED_MC)
7105 sd
= &per_cpu(core_domains
, i
);
7107 sd
= &per_cpu(phys_domains
, i
);
7109 cpu_attach_domain(sd
, rd
, i
);
7112 SCHED_CPUMASK_FREE((void *)allmasks
);
7117 free_sched_groups(cpu_map
, tmpmask
);
7118 SCHED_CPUMASK_FREE((void *)allmasks
);
7123 static cpumask_t
*doms_cur
; /* current sched domains */
7124 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7127 * Special case: If a kmalloc of a doms_cur partition (array of
7128 * cpumask_t) fails, then fallback to a single sched domain,
7129 * as determined by the single cpumask_t fallback_doms.
7131 static cpumask_t fallback_doms
;
7133 void __attribute__((weak
)) arch_update_cpu_topology(void)
7138 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7139 * For now this just excludes isolated cpus, but could be used to
7140 * exclude other special cases in the future.
7142 static int arch_init_sched_domains(const cpumask_t
*cpu_map
)
7146 arch_update_cpu_topology();
7148 doms_cur
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
7150 doms_cur
= &fallback_doms
;
7151 cpus_andnot(*doms_cur
, *cpu_map
, cpu_isolated_map
);
7152 err
= build_sched_domains(doms_cur
);
7153 register_sched_domain_sysctl();
7158 static void arch_destroy_sched_domains(const cpumask_t
*cpu_map
,
7161 free_sched_groups(cpu_map
, tmpmask
);
7165 * Detach sched domains from a group of cpus specified in cpu_map
7166 * These cpus will now be attached to the NULL domain
7168 static void detach_destroy_domains(const cpumask_t
*cpu_map
)
7173 unregister_sched_domain_sysctl();
7175 for_each_cpu_mask(i
, *cpu_map
)
7176 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7177 synchronize_sched();
7178 arch_destroy_sched_domains(cpu_map
, &tmpmask
);
7182 * Partition sched domains as specified by the 'ndoms_new'
7183 * cpumasks in the array doms_new[] of cpumasks. This compares
7184 * doms_new[] to the current sched domain partitioning, doms_cur[].
7185 * It destroys each deleted domain and builds each new domain.
7187 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7188 * The masks don't intersect (don't overlap.) We should setup one
7189 * sched domain for each mask. CPUs not in any of the cpumasks will
7190 * not be load balanced. If the same cpumask appears both in the
7191 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7194 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7195 * ownership of it and will kfree it when done with it. If the caller
7196 * failed the kmalloc call, then it can pass in doms_new == NULL,
7197 * and partition_sched_domains() will fallback to the single partition
7200 * Call with hotplug lock held
7202 void partition_sched_domains(int ndoms_new
, cpumask_t
*doms_new
)
7208 /* always unregister in case we don't destroy any domains */
7209 unregister_sched_domain_sysctl();
7211 if (doms_new
== NULL
) {
7213 doms_new
= &fallback_doms
;
7214 cpus_andnot(doms_new
[0], cpu_online_map
, cpu_isolated_map
);
7217 /* Destroy deleted domains */
7218 for (i
= 0; i
< ndoms_cur
; i
++) {
7219 for (j
= 0; j
< ndoms_new
; j
++) {
7220 if (cpus_equal(doms_cur
[i
], doms_new
[j
]))
7223 /* no match - a current sched domain not in new doms_new[] */
7224 detach_destroy_domains(doms_cur
+ i
);
7229 /* Build new domains */
7230 for (i
= 0; i
< ndoms_new
; i
++) {
7231 for (j
= 0; j
< ndoms_cur
; j
++) {
7232 if (cpus_equal(doms_new
[i
], doms_cur
[j
]))
7235 /* no match - add a new doms_new */
7236 build_sched_domains(doms_new
+ i
);
7241 /* Remember the new sched domains */
7242 if (doms_cur
!= &fallback_doms
)
7244 doms_cur
= doms_new
;
7245 ndoms_cur
= ndoms_new
;
7247 register_sched_domain_sysctl();
7252 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7253 int arch_reinit_sched_domains(void)
7258 detach_destroy_domains(&cpu_online_map
);
7259 err
= arch_init_sched_domains(&cpu_online_map
);
7265 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7269 if (buf
[0] != '0' && buf
[0] != '1')
7273 sched_smt_power_savings
= (buf
[0] == '1');
7275 sched_mc_power_savings
= (buf
[0] == '1');
7277 ret
= arch_reinit_sched_domains();
7279 return ret
? ret
: count
;
7282 #ifdef CONFIG_SCHED_MC
7283 static ssize_t
sched_mc_power_savings_show(struct sys_device
*dev
, char *page
)
7285 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7287 static ssize_t
sched_mc_power_savings_store(struct sys_device
*dev
,
7288 const char *buf
, size_t count
)
7290 return sched_power_savings_store(buf
, count
, 0);
7292 static SYSDEV_ATTR(sched_mc_power_savings
, 0644, sched_mc_power_savings_show
,
7293 sched_mc_power_savings_store
);
7296 #ifdef CONFIG_SCHED_SMT
7297 static ssize_t
sched_smt_power_savings_show(struct sys_device
*dev
, char *page
)
7299 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7301 static ssize_t
sched_smt_power_savings_store(struct sys_device
*dev
,
7302 const char *buf
, size_t count
)
7304 return sched_power_savings_store(buf
, count
, 1);
7306 static SYSDEV_ATTR(sched_smt_power_savings
, 0644, sched_smt_power_savings_show
,
7307 sched_smt_power_savings_store
);
7310 int sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7314 #ifdef CONFIG_SCHED_SMT
7316 err
= sysfs_create_file(&cls
->kset
.kobj
,
7317 &attr_sched_smt_power_savings
.attr
);
7319 #ifdef CONFIG_SCHED_MC
7320 if (!err
&& mc_capable())
7321 err
= sysfs_create_file(&cls
->kset
.kobj
,
7322 &attr_sched_mc_power_savings
.attr
);
7329 * Force a reinitialization of the sched domains hierarchy. The domains
7330 * and groups cannot be updated in place without racing with the balancing
7331 * code, so we temporarily attach all running cpus to the NULL domain
7332 * which will prevent rebalancing while the sched domains are recalculated.
7334 static int update_sched_domains(struct notifier_block
*nfb
,
7335 unsigned long action
, void *hcpu
)
7338 case CPU_UP_PREPARE
:
7339 case CPU_UP_PREPARE_FROZEN
:
7340 case CPU_DOWN_PREPARE
:
7341 case CPU_DOWN_PREPARE_FROZEN
:
7342 detach_destroy_domains(&cpu_online_map
);
7345 case CPU_UP_CANCELED
:
7346 case CPU_UP_CANCELED_FROZEN
:
7347 case CPU_DOWN_FAILED
:
7348 case CPU_DOWN_FAILED_FROZEN
:
7350 case CPU_ONLINE_FROZEN
:
7352 case CPU_DEAD_FROZEN
:
7354 * Fall through and re-initialise the domains.
7361 /* The hotplug lock is already held by cpu_up/cpu_down */
7362 arch_init_sched_domains(&cpu_online_map
);
7367 void __init
sched_init_smp(void)
7369 cpumask_t non_isolated_cpus
;
7371 #if defined(CONFIG_NUMA)
7372 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7374 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7377 arch_init_sched_domains(&cpu_online_map
);
7378 cpus_andnot(non_isolated_cpus
, cpu_possible_map
, cpu_isolated_map
);
7379 if (cpus_empty(non_isolated_cpus
))
7380 cpu_set(smp_processor_id(), non_isolated_cpus
);
7382 /* XXX: Theoretical race here - CPU may be hotplugged now */
7383 hotcpu_notifier(update_sched_domains
, 0);
7385 /* Move init over to a non-isolated CPU */
7386 if (set_cpus_allowed_ptr(current
, &non_isolated_cpus
) < 0)
7388 sched_init_granularity();
7391 void __init
sched_init_smp(void)
7393 #if defined(CONFIG_NUMA)
7394 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7396 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7398 sched_init_granularity();
7400 #endif /* CONFIG_SMP */
7402 int in_sched_functions(unsigned long addr
)
7404 return in_lock_functions(addr
) ||
7405 (addr
>= (unsigned long)__sched_text_start
7406 && addr
< (unsigned long)__sched_text_end
);
7409 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7411 cfs_rq
->tasks_timeline
= RB_ROOT
;
7412 #ifdef CONFIG_FAIR_GROUP_SCHED
7415 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7418 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7420 struct rt_prio_array
*array
;
7423 array
= &rt_rq
->active
;
7424 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7425 INIT_LIST_HEAD(array
->queue
+ i
);
7426 __clear_bit(i
, array
->bitmap
);
7428 /* delimiter for bitsearch: */
7429 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7431 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7432 rt_rq
->highest_prio
= MAX_RT_PRIO
;
7435 rt_rq
->rt_nr_migratory
= 0;
7436 rt_rq
->overloaded
= 0;
7440 rt_rq
->rt_throttled
= 0;
7441 rt_rq
->rt_runtime
= 0;
7442 spin_lock_init(&rt_rq
->rt_runtime_lock
);
7444 #ifdef CONFIG_RT_GROUP_SCHED
7445 rt_rq
->rt_nr_boosted
= 0;
7450 #ifdef CONFIG_FAIR_GROUP_SCHED
7451 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7452 struct sched_entity
*se
, int cpu
, int add
,
7453 struct sched_entity
*parent
)
7455 struct rq
*rq
= cpu_rq(cpu
);
7456 tg
->cfs_rq
[cpu
] = cfs_rq
;
7457 init_cfs_rq(cfs_rq
, rq
);
7460 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7463 /* se could be NULL for init_task_group */
7468 se
->cfs_rq
= &rq
->cfs
;
7470 se
->cfs_rq
= parent
->my_q
;
7473 se
->load
.weight
= tg
->shares
;
7474 se
->load
.inv_weight
= div64_64(1ULL<<32, se
->load
.weight
);
7475 se
->parent
= parent
;
7479 #ifdef CONFIG_RT_GROUP_SCHED
7480 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7481 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
7482 struct sched_rt_entity
*parent
)
7484 struct rq
*rq
= cpu_rq(cpu
);
7486 tg
->rt_rq
[cpu
] = rt_rq
;
7487 init_rt_rq(rt_rq
, rq
);
7489 rt_rq
->rt_se
= rt_se
;
7490 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7492 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7494 tg
->rt_se
[cpu
] = rt_se
;
7499 rt_se
->rt_rq
= &rq
->rt
;
7501 rt_se
->rt_rq
= parent
->my_q
;
7503 rt_se
->rt_rq
= &rq
->rt
;
7504 rt_se
->my_q
= rt_rq
;
7505 rt_se
->parent
= parent
;
7506 INIT_LIST_HEAD(&rt_se
->run_list
);
7510 void __init
sched_init(void)
7513 unsigned long alloc_size
= 0, ptr
;
7515 #ifdef CONFIG_FAIR_GROUP_SCHED
7516 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7518 #ifdef CONFIG_RT_GROUP_SCHED
7519 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7521 #ifdef CONFIG_USER_SCHED
7525 * As sched_init() is called before page_alloc is setup,
7526 * we use alloc_bootmem().
7529 ptr
= (unsigned long)alloc_bootmem_low(alloc_size
);
7531 #ifdef CONFIG_FAIR_GROUP_SCHED
7532 init_task_group
.se
= (struct sched_entity
**)ptr
;
7533 ptr
+= nr_cpu_ids
* sizeof(void **);
7535 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7536 ptr
+= nr_cpu_ids
* sizeof(void **);
7538 #ifdef CONFIG_USER_SCHED
7539 root_task_group
.se
= (struct sched_entity
**)ptr
;
7540 ptr
+= nr_cpu_ids
* sizeof(void **);
7542 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7543 ptr
+= nr_cpu_ids
* sizeof(void **);
7546 #ifdef CONFIG_RT_GROUP_SCHED
7547 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7548 ptr
+= nr_cpu_ids
* sizeof(void **);
7550 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7551 ptr
+= nr_cpu_ids
* sizeof(void **);
7553 #ifdef CONFIG_USER_SCHED
7554 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7555 ptr
+= nr_cpu_ids
* sizeof(void **);
7557 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7558 ptr
+= nr_cpu_ids
* sizeof(void **);
7564 init_defrootdomain();
7567 init_rt_bandwidth(&def_rt_bandwidth
,
7568 global_rt_period(), global_rt_runtime());
7570 #ifdef CONFIG_RT_GROUP_SCHED
7571 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7572 global_rt_period(), global_rt_runtime());
7573 #ifdef CONFIG_USER_SCHED
7574 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7575 global_rt_period(), RUNTIME_INF
);
7579 #ifdef CONFIG_GROUP_SCHED
7580 list_add(&init_task_group
.list
, &task_groups
);
7583 for_each_possible_cpu(i
) {
7587 spin_lock_init(&rq
->lock
);
7588 lockdep_set_class(&rq
->lock
, &rq
->rq_lock_key
);
7591 update_last_tick_seen(rq
);
7592 init_cfs_rq(&rq
->cfs
, rq
);
7593 init_rt_rq(&rq
->rt
, rq
);
7594 #ifdef CONFIG_FAIR_GROUP_SCHED
7595 init_task_group
.shares
= init_task_group_load
;
7596 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7597 #ifdef CONFIG_CGROUP_SCHED
7599 * How much cpu bandwidth does init_task_group get?
7601 * In case of task-groups formed thr' the cgroup filesystem, it
7602 * gets 100% of the cpu resources in the system. This overall
7603 * system cpu resource is divided among the tasks of
7604 * init_task_group and its child task-groups in a fair manner,
7605 * based on each entity's (task or task-group's) weight
7606 * (se->load.weight).
7608 * In other words, if init_task_group has 10 tasks of weight
7609 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7610 * then A0's share of the cpu resource is:
7612 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7614 * We achieve this by letting init_task_group's tasks sit
7615 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7617 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
7618 #elif defined CONFIG_USER_SCHED
7619 root_task_group
.shares
= NICE_0_LOAD
;
7620 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
7622 * In case of task-groups formed thr' the user id of tasks,
7623 * init_task_group represents tasks belonging to root user.
7624 * Hence it forms a sibling of all subsequent groups formed.
7625 * In this case, init_task_group gets only a fraction of overall
7626 * system cpu resource, based on the weight assigned to root
7627 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
7628 * by letting tasks of init_task_group sit in a separate cfs_rq
7629 * (init_cfs_rq) and having one entity represent this group of
7630 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
7632 init_tg_cfs_entry(&init_task_group
,
7633 &per_cpu(init_cfs_rq
, i
),
7634 &per_cpu(init_sched_entity
, i
), i
, 1,
7635 root_task_group
.se
[i
]);
7638 #endif /* CONFIG_FAIR_GROUP_SCHED */
7640 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7641 #ifdef CONFIG_RT_GROUP_SCHED
7642 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7643 #ifdef CONFIG_CGROUP_SCHED
7644 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
7645 #elif defined CONFIG_USER_SCHED
7646 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
7647 init_tg_rt_entry(&init_task_group
,
7648 &per_cpu(init_rt_rq
, i
),
7649 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
7650 root_task_group
.rt_se
[i
]);
7654 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7655 rq
->cpu_load
[j
] = 0;
7659 rq
->active_balance
= 0;
7660 rq
->next_balance
= jiffies
;
7663 rq
->migration_thread
= NULL
;
7664 INIT_LIST_HEAD(&rq
->migration_queue
);
7665 rq_attach_root(rq
, &def_root_domain
);
7668 atomic_set(&rq
->nr_iowait
, 0);
7671 set_load_weight(&init_task
);
7673 #ifdef CONFIG_PREEMPT_NOTIFIERS
7674 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7678 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
, NULL
);
7681 #ifdef CONFIG_RT_MUTEXES
7682 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7686 * The boot idle thread does lazy MMU switching as well:
7688 atomic_inc(&init_mm
.mm_count
);
7689 enter_lazy_tlb(&init_mm
, current
);
7692 * Make us the idle thread. Technically, schedule() should not be
7693 * called from this thread, however somewhere below it might be,
7694 * but because we are the idle thread, we just pick up running again
7695 * when this runqueue becomes "idle".
7697 init_idle(current
, smp_processor_id());
7699 * During early bootup we pretend to be a normal task:
7701 current
->sched_class
= &fair_sched_class
;
7703 scheduler_running
= 1;
7706 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7707 void __might_sleep(char *file
, int line
)
7710 static unsigned long prev_jiffy
; /* ratelimiting */
7712 if ((in_atomic() || irqs_disabled()) &&
7713 system_state
== SYSTEM_RUNNING
&& !oops_in_progress
) {
7714 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7716 prev_jiffy
= jiffies
;
7717 printk(KERN_ERR
"BUG: sleeping function called from invalid"
7718 " context at %s:%d\n", file
, line
);
7719 printk("in_atomic():%d, irqs_disabled():%d\n",
7720 in_atomic(), irqs_disabled());
7721 debug_show_held_locks(current
);
7722 if (irqs_disabled())
7723 print_irqtrace_events(current
);
7728 EXPORT_SYMBOL(__might_sleep
);
7731 #ifdef CONFIG_MAGIC_SYSRQ
7732 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7735 update_rq_clock(rq
);
7736 on_rq
= p
->se
.on_rq
;
7738 deactivate_task(rq
, p
, 0);
7739 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7741 activate_task(rq
, p
, 0);
7742 resched_task(rq
->curr
);
7746 void normalize_rt_tasks(void)
7748 struct task_struct
*g
, *p
;
7749 unsigned long flags
;
7752 read_lock_irqsave(&tasklist_lock
, flags
);
7753 do_each_thread(g
, p
) {
7755 * Only normalize user tasks:
7760 p
->se
.exec_start
= 0;
7761 #ifdef CONFIG_SCHEDSTATS
7762 p
->se
.wait_start
= 0;
7763 p
->se
.sleep_start
= 0;
7764 p
->se
.block_start
= 0;
7766 task_rq(p
)->clock
= 0;
7770 * Renice negative nice level userspace
7773 if (TASK_NICE(p
) < 0 && p
->mm
)
7774 set_user_nice(p
, 0);
7778 spin_lock(&p
->pi_lock
);
7779 rq
= __task_rq_lock(p
);
7781 normalize_task(rq
, p
);
7783 __task_rq_unlock(rq
);
7784 spin_unlock(&p
->pi_lock
);
7785 } while_each_thread(g
, p
);
7787 read_unlock_irqrestore(&tasklist_lock
, flags
);
7790 #endif /* CONFIG_MAGIC_SYSRQ */
7794 * These functions are only useful for the IA64 MCA handling.
7796 * They can only be called when the whole system has been
7797 * stopped - every CPU needs to be quiescent, and no scheduling
7798 * activity can take place. Using them for anything else would
7799 * be a serious bug, and as a result, they aren't even visible
7800 * under any other configuration.
7804 * curr_task - return the current task for a given cpu.
7805 * @cpu: the processor in question.
7807 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7809 struct task_struct
*curr_task(int cpu
)
7811 return cpu_curr(cpu
);
7815 * set_curr_task - set the current task for a given cpu.
7816 * @cpu: the processor in question.
7817 * @p: the task pointer to set.
7819 * Description: This function must only be used when non-maskable interrupts
7820 * are serviced on a separate stack. It allows the architecture to switch the
7821 * notion of the current task on a cpu in a non-blocking manner. This function
7822 * must be called with all CPU's synchronized, and interrupts disabled, the
7823 * and caller must save the original value of the current task (see
7824 * curr_task() above) and restore that value before reenabling interrupts and
7825 * re-starting the system.
7827 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7829 void set_curr_task(int cpu
, struct task_struct
*p
)
7836 #ifdef CONFIG_FAIR_GROUP_SCHED
7837 static void free_fair_sched_group(struct task_group
*tg
)
7841 for_each_possible_cpu(i
) {
7843 kfree(tg
->cfs_rq
[i
]);
7853 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7855 struct cfs_rq
*cfs_rq
;
7856 struct sched_entity
*se
, *parent_se
;
7860 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
7863 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
7867 tg
->shares
= NICE_0_LOAD
;
7869 for_each_possible_cpu(i
) {
7872 cfs_rq
= kmalloc_node(sizeof(struct cfs_rq
),
7873 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7877 se
= kmalloc_node(sizeof(struct sched_entity
),
7878 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7882 parent_se
= parent
? parent
->se
[i
] : NULL
;
7883 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent_se
);
7892 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7894 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
7895 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
7898 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
7900 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
7903 static inline void free_fair_sched_group(struct task_group
*tg
)
7908 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7913 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7917 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
7922 #ifdef CONFIG_RT_GROUP_SCHED
7923 static void free_rt_sched_group(struct task_group
*tg
)
7927 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
7929 for_each_possible_cpu(i
) {
7931 kfree(tg
->rt_rq
[i
]);
7933 kfree(tg
->rt_se
[i
]);
7941 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7943 struct rt_rq
*rt_rq
;
7944 struct sched_rt_entity
*rt_se
, *parent_se
;
7948 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
7951 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
7955 init_rt_bandwidth(&tg
->rt_bandwidth
,
7956 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
7958 for_each_possible_cpu(i
) {
7961 rt_rq
= kmalloc_node(sizeof(struct rt_rq
),
7962 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7966 rt_se
= kmalloc_node(sizeof(struct sched_rt_entity
),
7967 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7971 parent_se
= parent
? parent
->rt_se
[i
] : NULL
;
7972 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent_se
);
7981 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
7983 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
7984 &cpu_rq(cpu
)->leaf_rt_rq_list
);
7987 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
7989 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
7992 static inline void free_rt_sched_group(struct task_group
*tg
)
7997 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8002 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8006 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8011 #ifdef CONFIG_GROUP_SCHED
8012 static void free_sched_group(struct task_group
*tg
)
8014 free_fair_sched_group(tg
);
8015 free_rt_sched_group(tg
);
8019 /* allocate runqueue etc for a new task group */
8020 struct task_group
*sched_create_group(struct task_group
*parent
)
8022 struct task_group
*tg
;
8023 unsigned long flags
;
8026 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8028 return ERR_PTR(-ENOMEM
);
8030 if (!alloc_fair_sched_group(tg
, parent
))
8033 if (!alloc_rt_sched_group(tg
, parent
))
8036 spin_lock_irqsave(&task_group_lock
, flags
);
8037 for_each_possible_cpu(i
) {
8038 register_fair_sched_group(tg
, i
);
8039 register_rt_sched_group(tg
, i
);
8041 list_add_rcu(&tg
->list
, &task_groups
);
8042 spin_unlock_irqrestore(&task_group_lock
, flags
);
8047 free_sched_group(tg
);
8048 return ERR_PTR(-ENOMEM
);
8051 /* rcu callback to free various structures associated with a task group */
8052 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8054 /* now it should be safe to free those cfs_rqs */
8055 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8058 /* Destroy runqueue etc associated with a task group */
8059 void sched_destroy_group(struct task_group
*tg
)
8061 unsigned long flags
;
8064 spin_lock_irqsave(&task_group_lock
, flags
);
8065 for_each_possible_cpu(i
) {
8066 unregister_fair_sched_group(tg
, i
);
8067 unregister_rt_sched_group(tg
, i
);
8069 list_del_rcu(&tg
->list
);
8070 spin_unlock_irqrestore(&task_group_lock
, flags
);
8072 /* wait for possible concurrent references to cfs_rqs complete */
8073 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8076 /* change task's runqueue when it moves between groups.
8077 * The caller of this function should have put the task in its new group
8078 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8079 * reflect its new group.
8081 void sched_move_task(struct task_struct
*tsk
)
8084 unsigned long flags
;
8087 rq
= task_rq_lock(tsk
, &flags
);
8089 update_rq_clock(rq
);
8091 running
= task_current(rq
, tsk
);
8092 on_rq
= tsk
->se
.on_rq
;
8095 dequeue_task(rq
, tsk
, 0);
8096 if (unlikely(running
))
8097 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8099 set_task_rq(tsk
, task_cpu(tsk
));
8101 #ifdef CONFIG_FAIR_GROUP_SCHED
8102 if (tsk
->sched_class
->moved_group
)
8103 tsk
->sched_class
->moved_group(tsk
);
8106 if (unlikely(running
))
8107 tsk
->sched_class
->set_curr_task(rq
);
8109 enqueue_task(rq
, tsk
, 0);
8111 task_rq_unlock(rq
, &flags
);
8115 #ifdef CONFIG_FAIR_GROUP_SCHED
8116 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8118 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8119 struct rq
*rq
= cfs_rq
->rq
;
8122 spin_lock_irq(&rq
->lock
);
8126 dequeue_entity(cfs_rq
, se
, 0);
8128 se
->load
.weight
= shares
;
8129 se
->load
.inv_weight
= div64_64((1ULL<<32), shares
);
8132 enqueue_entity(cfs_rq
, se
, 0);
8134 spin_unlock_irq(&rq
->lock
);
8137 static DEFINE_MUTEX(shares_mutex
);
8139 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8142 unsigned long flags
;
8145 * We can't change the weight of the root cgroup.
8151 * A weight of 0 or 1 can cause arithmetics problems.
8152 * (The default weight is 1024 - so there's no practical
8153 * limitation from this.)
8158 mutex_lock(&shares_mutex
);
8159 if (tg
->shares
== shares
)
8162 spin_lock_irqsave(&task_group_lock
, flags
);
8163 for_each_possible_cpu(i
)
8164 unregister_fair_sched_group(tg
, i
);
8165 spin_unlock_irqrestore(&task_group_lock
, flags
);
8167 /* wait for any ongoing reference to this group to finish */
8168 synchronize_sched();
8171 * Now we are free to modify the group's share on each cpu
8172 * w/o tripping rebalance_share or load_balance_fair.
8174 tg
->shares
= shares
;
8175 for_each_possible_cpu(i
)
8176 set_se_shares(tg
->se
[i
], shares
);
8179 * Enable load balance activity on this group, by inserting it back on
8180 * each cpu's rq->leaf_cfs_rq_list.
8182 spin_lock_irqsave(&task_group_lock
, flags
);
8183 for_each_possible_cpu(i
)
8184 register_fair_sched_group(tg
, i
);
8185 spin_unlock_irqrestore(&task_group_lock
, flags
);
8187 mutex_unlock(&shares_mutex
);
8191 unsigned long sched_group_shares(struct task_group
*tg
)
8197 #ifdef CONFIG_RT_GROUP_SCHED
8199 * Ensure that the real time constraints are schedulable.
8201 static DEFINE_MUTEX(rt_constraints_mutex
);
8203 static unsigned long to_ratio(u64 period
, u64 runtime
)
8205 if (runtime
== RUNTIME_INF
)
8208 return div64_64(runtime
<< 16, period
);
8211 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8213 struct task_group
*tgi
;
8214 unsigned long total
= 0;
8215 unsigned long global_ratio
=
8216 to_ratio(global_rt_period(), global_rt_runtime());
8219 list_for_each_entry_rcu(tgi
, &task_groups
, list
) {
8223 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8224 tgi
->rt_bandwidth
.rt_runtime
);
8228 return total
+ to_ratio(period
, runtime
) < global_ratio
;
8231 /* Must be called with tasklist_lock held */
8232 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8234 struct task_struct
*g
, *p
;
8235 do_each_thread(g
, p
) {
8236 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8238 } while_each_thread(g
, p
);
8242 static int tg_set_bandwidth(struct task_group
*tg
,
8243 u64 rt_period
, u64 rt_runtime
)
8247 mutex_lock(&rt_constraints_mutex
);
8248 read_lock(&tasklist_lock
);
8249 if (rt_runtime
== 0 && tg_has_rt_tasks(tg
)) {
8253 if (!__rt_schedulable(tg
, rt_period
, rt_runtime
)) {
8258 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8259 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8260 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8262 for_each_possible_cpu(i
) {
8263 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8265 spin_lock(&rt_rq
->rt_runtime_lock
);
8266 rt_rq
->rt_runtime
= rt_runtime
;
8267 spin_unlock(&rt_rq
->rt_runtime_lock
);
8269 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8271 read_unlock(&tasklist_lock
);
8272 mutex_unlock(&rt_constraints_mutex
);
8277 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8279 u64 rt_runtime
, rt_period
;
8281 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8282 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8283 if (rt_runtime_us
< 0)
8284 rt_runtime
= RUNTIME_INF
;
8286 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8289 long sched_group_rt_runtime(struct task_group
*tg
)
8293 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8296 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8297 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8298 return rt_runtime_us
;
8301 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8303 u64 rt_runtime
, rt_period
;
8305 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8306 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8308 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8311 long sched_group_rt_period(struct task_group
*tg
)
8315 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8316 do_div(rt_period_us
, NSEC_PER_USEC
);
8317 return rt_period_us
;
8320 static int sched_rt_global_constraints(void)
8324 mutex_lock(&rt_constraints_mutex
);
8325 if (!__rt_schedulable(NULL
, 1, 0))
8327 mutex_unlock(&rt_constraints_mutex
);
8332 static int sched_rt_global_constraints(void)
8334 unsigned long flags
;
8337 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8338 for_each_possible_cpu(i
) {
8339 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8341 spin_lock(&rt_rq
->rt_runtime_lock
);
8342 rt_rq
->rt_runtime
= global_rt_runtime();
8343 spin_unlock(&rt_rq
->rt_runtime_lock
);
8345 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8351 int sched_rt_handler(struct ctl_table
*table
, int write
,
8352 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
8356 int old_period
, old_runtime
;
8357 static DEFINE_MUTEX(mutex
);
8360 old_period
= sysctl_sched_rt_period
;
8361 old_runtime
= sysctl_sched_rt_runtime
;
8363 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
8365 if (!ret
&& write
) {
8366 ret
= sched_rt_global_constraints();
8368 sysctl_sched_rt_period
= old_period
;
8369 sysctl_sched_rt_runtime
= old_runtime
;
8371 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8372 def_rt_bandwidth
.rt_period
=
8373 ns_to_ktime(global_rt_period());
8376 mutex_unlock(&mutex
);
8381 #ifdef CONFIG_CGROUP_SCHED
8383 /* return corresponding task_group object of a cgroup */
8384 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8386 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8387 struct task_group
, css
);
8390 static struct cgroup_subsys_state
*
8391 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8393 struct task_group
*tg
, *parent
;
8395 if (!cgrp
->parent
) {
8396 /* This is early initialization for the top cgroup */
8397 init_task_group
.css
.cgroup
= cgrp
;
8398 return &init_task_group
.css
;
8401 parent
= cgroup_tg(cgrp
->parent
);
8402 tg
= sched_create_group(parent
);
8404 return ERR_PTR(-ENOMEM
);
8406 /* Bind the cgroup to task_group object we just created */
8407 tg
->css
.cgroup
= cgrp
;
8413 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8415 struct task_group
*tg
= cgroup_tg(cgrp
);
8417 sched_destroy_group(tg
);
8421 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8422 struct task_struct
*tsk
)
8424 #ifdef CONFIG_RT_GROUP_SCHED
8425 /* Don't accept realtime tasks when there is no way for them to run */
8426 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
8429 /* We don't support RT-tasks being in separate groups */
8430 if (tsk
->sched_class
!= &fair_sched_class
)
8438 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8439 struct cgroup
*old_cont
, struct task_struct
*tsk
)
8441 sched_move_task(tsk
);
8444 #ifdef CONFIG_FAIR_GROUP_SCHED
8445 static int cpu_shares_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8448 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8451 static u64
cpu_shares_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8453 struct task_group
*tg
= cgroup_tg(cgrp
);
8455 return (u64
) tg
->shares
;
8459 #ifdef CONFIG_RT_GROUP_SCHED
8460 static ssize_t
cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8462 const char __user
*userbuf
,
8463 size_t nbytes
, loff_t
*unused_ppos
)
8472 if (nbytes
>= sizeof(buffer
))
8474 if (copy_from_user(buffer
, userbuf
, nbytes
))
8477 buffer
[nbytes
] = 0; /* nul-terminate */
8479 /* strip newline if necessary */
8480 if (nbytes
&& (buffer
[nbytes
-1] == '\n'))
8481 buffer
[nbytes
-1] = 0;
8482 val
= simple_strtoll(buffer
, &end
, 0);
8486 /* Pass to subsystem */
8487 retval
= sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8493 static ssize_t
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
,
8495 char __user
*buf
, size_t nbytes
,
8499 long val
= sched_group_rt_runtime(cgroup_tg(cgrp
));
8500 int len
= sprintf(tmp
, "%ld\n", val
);
8502 return simple_read_from_buffer(buf
, nbytes
, ppos
, tmp
, len
);
8505 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8508 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8511 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8513 return sched_group_rt_period(cgroup_tg(cgrp
));
8517 static struct cftype cpu_files
[] = {
8518 #ifdef CONFIG_FAIR_GROUP_SCHED
8521 .read_uint
= cpu_shares_read_uint
,
8522 .write_uint
= cpu_shares_write_uint
,
8525 #ifdef CONFIG_RT_GROUP_SCHED
8527 .name
= "rt_runtime_us",
8528 .read
= cpu_rt_runtime_read
,
8529 .write
= cpu_rt_runtime_write
,
8532 .name
= "rt_period_us",
8533 .read_uint
= cpu_rt_period_read_uint
,
8534 .write_uint
= cpu_rt_period_write_uint
,
8539 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8541 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8544 struct cgroup_subsys cpu_cgroup_subsys
= {
8546 .create
= cpu_cgroup_create
,
8547 .destroy
= cpu_cgroup_destroy
,
8548 .can_attach
= cpu_cgroup_can_attach
,
8549 .attach
= cpu_cgroup_attach
,
8550 .populate
= cpu_cgroup_populate
,
8551 .subsys_id
= cpu_cgroup_subsys_id
,
8555 #endif /* CONFIG_CGROUP_SCHED */
8557 #ifdef CONFIG_CGROUP_CPUACCT
8560 * CPU accounting code for task groups.
8562 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8563 * (balbir@in.ibm.com).
8566 /* track cpu usage of a group of tasks */
8568 struct cgroup_subsys_state css
;
8569 /* cpuusage holds pointer to a u64-type object on every cpu */
8573 struct cgroup_subsys cpuacct_subsys
;
8575 /* return cpu accounting group corresponding to this container */
8576 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8578 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8579 struct cpuacct
, css
);
8582 /* return cpu accounting group to which this task belongs */
8583 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8585 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8586 struct cpuacct
, css
);
8589 /* create a new cpu accounting group */
8590 static struct cgroup_subsys_state
*cpuacct_create(
8591 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8593 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8596 return ERR_PTR(-ENOMEM
);
8598 ca
->cpuusage
= alloc_percpu(u64
);
8599 if (!ca
->cpuusage
) {
8601 return ERR_PTR(-ENOMEM
);
8607 /* destroy an existing cpu accounting group */
8609 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8611 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8613 free_percpu(ca
->cpuusage
);
8617 /* return total cpu usage (in nanoseconds) of a group */
8618 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8620 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8621 u64 totalcpuusage
= 0;
8624 for_each_possible_cpu(i
) {
8625 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8628 * Take rq->lock to make 64-bit addition safe on 32-bit
8631 spin_lock_irq(&cpu_rq(i
)->lock
);
8632 totalcpuusage
+= *cpuusage
;
8633 spin_unlock_irq(&cpu_rq(i
)->lock
);
8636 return totalcpuusage
;
8639 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8642 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8651 for_each_possible_cpu(i
) {
8652 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8654 spin_lock_irq(&cpu_rq(i
)->lock
);
8656 spin_unlock_irq(&cpu_rq(i
)->lock
);
8662 static struct cftype files
[] = {
8665 .read_uint
= cpuusage_read
,
8666 .write_uint
= cpuusage_write
,
8670 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8672 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8676 * charge this task's execution time to its accounting group.
8678 * called with rq->lock held.
8680 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8684 if (!cpuacct_subsys
.active
)
8689 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, task_cpu(tsk
));
8691 *cpuusage
+= cputime
;
8695 struct cgroup_subsys cpuacct_subsys
= {
8697 .create
= cpuacct_create
,
8698 .destroy
= cpuacct_destroy
,
8699 .populate
= cpuacct_populate
,
8700 .subsys_id
= cpuacct_subsys_id
,
8702 #endif /* CONFIG_CGROUP_CPUACCT */