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
277 #ifdef CONFIG_FAIR_GROUP_SCHED
278 /* Default task group's sched entity on each cpu */
279 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
280 /* Default task group's cfs_rq on each cpu */
281 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
284 #ifdef CONFIG_RT_GROUP_SCHED
285 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
286 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
290 /* task_group_lock serializes add/remove of task groups and also changes to
291 * a task group's cpu shares.
293 static DEFINE_SPINLOCK(task_group_lock
);
295 /* doms_cur_mutex serializes access to doms_cur[] array */
296 static DEFINE_MUTEX(doms_cur_mutex
);
298 #ifdef CONFIG_FAIR_GROUP_SCHED
299 #ifdef CONFIG_USER_SCHED
300 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
302 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
305 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
308 /* Default task group.
309 * Every task in system belong to this group at bootup.
311 struct task_group init_task_group
;
313 /* return group to which a task belongs */
314 static inline struct task_group
*task_group(struct task_struct
*p
)
316 struct task_group
*tg
;
318 #ifdef CONFIG_USER_SCHED
320 #elif defined(CONFIG_CGROUP_SCHED)
321 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
322 struct task_group
, css
);
324 tg
= &init_task_group
;
329 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
330 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
332 #ifdef CONFIG_FAIR_GROUP_SCHED
333 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
334 p
->se
.parent
= task_group(p
)->se
[cpu
];
337 #ifdef CONFIG_RT_GROUP_SCHED
338 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
339 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
343 static inline void lock_doms_cur(void)
345 mutex_lock(&doms_cur_mutex
);
348 static inline void unlock_doms_cur(void)
350 mutex_unlock(&doms_cur_mutex
);
355 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
356 static inline void lock_doms_cur(void) { }
357 static inline void unlock_doms_cur(void) { }
359 #endif /* CONFIG_GROUP_SCHED */
361 /* CFS-related fields in a runqueue */
363 struct load_weight load
;
364 unsigned long nr_running
;
369 struct rb_root tasks_timeline
;
370 struct rb_node
*rb_leftmost
;
371 struct rb_node
*rb_load_balance_curr
;
372 /* 'curr' points to currently running entity on this cfs_rq.
373 * It is set to NULL otherwise (i.e when none are currently running).
375 struct sched_entity
*curr
, *next
;
377 unsigned long nr_spread_over
;
379 #ifdef CONFIG_FAIR_GROUP_SCHED
380 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
383 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
384 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
385 * (like users, containers etc.)
387 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
388 * list is used during load balance.
390 struct list_head leaf_cfs_rq_list
;
391 struct task_group
*tg
; /* group that "owns" this runqueue */
395 /* Real-Time classes' related field in a runqueue: */
397 struct rt_prio_array active
;
398 unsigned long rt_nr_running
;
399 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
400 int highest_prio
; /* highest queued rt task prio */
403 unsigned long rt_nr_migratory
;
409 /* Nests inside the rq lock: */
410 spinlock_t rt_runtime_lock
;
412 #ifdef CONFIG_RT_GROUP_SCHED
413 unsigned long rt_nr_boosted
;
416 struct list_head leaf_rt_rq_list
;
417 struct task_group
*tg
;
418 struct sched_rt_entity
*rt_se
;
425 * We add the notion of a root-domain which will be used to define per-domain
426 * variables. Each exclusive cpuset essentially defines an island domain by
427 * fully partitioning the member cpus from any other cpuset. Whenever a new
428 * exclusive cpuset is created, we also create and attach a new root-domain
438 * The "RT overload" flag: it gets set if a CPU has more than
439 * one runnable RT task.
446 * By default the system creates a single root-domain with all cpus as
447 * members (mimicking the global state we have today).
449 static struct root_domain def_root_domain
;
454 * This is the main, per-CPU runqueue data structure.
456 * Locking rule: those places that want to lock multiple runqueues
457 * (such as the load balancing or the thread migration code), lock
458 * acquire operations must be ordered by ascending &runqueue.
465 * nr_running and cpu_load should be in the same cacheline because
466 * remote CPUs use both these fields when doing load calculation.
468 unsigned long nr_running
;
469 #define CPU_LOAD_IDX_MAX 5
470 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
471 unsigned char idle_at_tick
;
473 unsigned long last_tick_seen
;
474 unsigned char in_nohz_recently
;
476 /* capture load from *all* tasks on this cpu: */
477 struct load_weight load
;
478 unsigned long nr_load_updates
;
484 #ifdef CONFIG_FAIR_GROUP_SCHED
485 /* list of leaf cfs_rq on this cpu: */
486 struct list_head leaf_cfs_rq_list
;
488 #ifdef CONFIG_RT_GROUP_SCHED
489 struct list_head leaf_rt_rq_list
;
493 * This is part of a global counter where only the total sum
494 * over all CPUs matters. A task can increase this counter on
495 * one CPU and if it got migrated afterwards it may decrease
496 * it on another CPU. Always updated under the runqueue lock:
498 unsigned long nr_uninterruptible
;
500 struct task_struct
*curr
, *idle
;
501 unsigned long next_balance
;
502 struct mm_struct
*prev_mm
;
504 u64 clock
, prev_clock_raw
;
507 unsigned int clock_warps
, clock_overflows
, clock_underflows
;
509 unsigned int clock_deep_idle_events
;
515 struct root_domain
*rd
;
516 struct sched_domain
*sd
;
518 /* For active balancing */
521 /* cpu of this runqueue: */
524 struct task_struct
*migration_thread
;
525 struct list_head migration_queue
;
528 #ifdef CONFIG_SCHED_HRTICK
529 unsigned long hrtick_flags
;
530 ktime_t hrtick_expire
;
531 struct hrtimer hrtick_timer
;
534 #ifdef CONFIG_SCHEDSTATS
536 struct sched_info rq_sched_info
;
538 /* sys_sched_yield() stats */
539 unsigned int yld_exp_empty
;
540 unsigned int yld_act_empty
;
541 unsigned int yld_both_empty
;
542 unsigned int yld_count
;
544 /* schedule() stats */
545 unsigned int sched_switch
;
546 unsigned int sched_count
;
547 unsigned int sched_goidle
;
549 /* try_to_wake_up() stats */
550 unsigned int ttwu_count
;
551 unsigned int ttwu_local
;
554 unsigned int bkl_count
;
556 struct lock_class_key rq_lock_key
;
559 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
561 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
)
563 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
);
566 static inline int cpu_of(struct rq
*rq
)
576 static inline bool nohz_on(int cpu
)
578 return tick_get_tick_sched(cpu
)->nohz_mode
!= NOHZ_MODE_INACTIVE
;
581 static inline u64
max_skipped_ticks(struct rq
*rq
)
583 return nohz_on(cpu_of(rq
)) ? jiffies
- rq
->last_tick_seen
+ 2 : 1;
586 static inline void update_last_tick_seen(struct rq
*rq
)
588 rq
->last_tick_seen
= jiffies
;
591 static inline u64
max_skipped_ticks(struct rq
*rq
)
596 static inline void update_last_tick_seen(struct rq
*rq
)
602 * Update the per-runqueue clock, as finegrained as the platform can give
603 * us, but without assuming monotonicity, etc.:
605 static void __update_rq_clock(struct rq
*rq
)
607 u64 prev_raw
= rq
->prev_clock_raw
;
608 u64 now
= sched_clock();
609 s64 delta
= now
- prev_raw
;
610 u64 clock
= rq
->clock
;
612 #ifdef CONFIG_SCHED_DEBUG
613 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
616 * Protect against sched_clock() occasionally going backwards:
618 if (unlikely(delta
< 0)) {
623 * Catch too large forward jumps too:
625 u64 max_jump
= max_skipped_ticks(rq
) * TICK_NSEC
;
626 u64 max_time
= rq
->tick_timestamp
+ max_jump
;
628 if (unlikely(clock
+ delta
> max_time
)) {
629 if (clock
< max_time
)
633 rq
->clock_overflows
++;
635 if (unlikely(delta
> rq
->clock_max_delta
))
636 rq
->clock_max_delta
= delta
;
641 rq
->prev_clock_raw
= now
;
645 static void update_rq_clock(struct rq
*rq
)
647 if (likely(smp_processor_id() == cpu_of(rq
)))
648 __update_rq_clock(rq
);
652 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
653 * See detach_destroy_domains: synchronize_sched for details.
655 * The domain tree of any CPU may only be accessed from within
656 * preempt-disabled sections.
658 #define for_each_domain(cpu, __sd) \
659 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
661 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
662 #define this_rq() (&__get_cpu_var(runqueues))
663 #define task_rq(p) cpu_rq(task_cpu(p))
664 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
667 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
669 #ifdef CONFIG_SCHED_DEBUG
670 # define const_debug __read_mostly
672 # define const_debug static const
676 * Debugging: various feature bits
679 SCHED_FEAT_NEW_FAIR_SLEEPERS
= 1,
680 SCHED_FEAT_WAKEUP_PREEMPT
= 2,
681 SCHED_FEAT_START_DEBIT
= 4,
682 SCHED_FEAT_AFFINE_WAKEUPS
= 8,
683 SCHED_FEAT_CACHE_HOT_BUDDY
= 16,
684 SCHED_FEAT_SYNC_WAKEUPS
= 32,
685 SCHED_FEAT_HRTICK
= 64,
686 SCHED_FEAT_DOUBLE_TICK
= 128,
687 SCHED_FEAT_NORMALIZED_SLEEPER
= 256,
690 const_debug
unsigned int sysctl_sched_features
=
691 SCHED_FEAT_NEW_FAIR_SLEEPERS
* 1 |
692 SCHED_FEAT_WAKEUP_PREEMPT
* 1 |
693 SCHED_FEAT_START_DEBIT
* 1 |
694 SCHED_FEAT_AFFINE_WAKEUPS
* 1 |
695 SCHED_FEAT_CACHE_HOT_BUDDY
* 1 |
696 SCHED_FEAT_SYNC_WAKEUPS
* 1 |
697 SCHED_FEAT_HRTICK
* 1 |
698 SCHED_FEAT_DOUBLE_TICK
* 0 |
699 SCHED_FEAT_NORMALIZED_SLEEPER
* 1;
701 #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
704 * Number of tasks to iterate in a single balance run.
705 * Limited because this is done with IRQs disabled.
707 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
710 * period over which we measure -rt task cpu usage in us.
713 unsigned int sysctl_sched_rt_period
= 1000000;
715 static __read_mostly
int scheduler_running
;
718 * part of the period that we allow rt tasks to run in us.
721 int sysctl_sched_rt_runtime
= 950000;
723 static inline u64
global_rt_period(void)
725 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
728 static inline u64
global_rt_runtime(void)
730 if (sysctl_sched_rt_period
< 0)
733 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
736 static const unsigned long long time_sync_thresh
= 100000;
738 static DEFINE_PER_CPU(unsigned long long, time_offset
);
739 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time
);
742 * Global lock which we take every now and then to synchronize
743 * the CPUs time. This method is not warp-safe, but it's good
744 * enough to synchronize slowly diverging time sources and thus
745 * it's good enough for tracing:
747 static DEFINE_SPINLOCK(time_sync_lock
);
748 static unsigned long long prev_global_time
;
750 static unsigned long long __sync_cpu_clock(cycles_t time
, int cpu
)
754 spin_lock_irqsave(&time_sync_lock
, flags
);
756 if (time
< prev_global_time
) {
757 per_cpu(time_offset
, cpu
) += prev_global_time
- time
;
758 time
= prev_global_time
;
760 prev_global_time
= time
;
763 spin_unlock_irqrestore(&time_sync_lock
, flags
);
768 static unsigned long long __cpu_clock(int cpu
)
770 unsigned long long now
;
775 * Only call sched_clock() if the scheduler has already been
776 * initialized (some code might call cpu_clock() very early):
778 if (unlikely(!scheduler_running
))
781 local_irq_save(flags
);
785 local_irq_restore(flags
);
791 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
792 * clock constructed from sched_clock():
794 unsigned long long cpu_clock(int cpu
)
796 unsigned long long prev_cpu_time
, time
, delta_time
;
798 prev_cpu_time
= per_cpu(prev_cpu_time
, cpu
);
799 time
= __cpu_clock(cpu
) + per_cpu(time_offset
, cpu
);
800 delta_time
= time
-prev_cpu_time
;
802 if (unlikely(delta_time
> time_sync_thresh
))
803 time
= __sync_cpu_clock(time
, cpu
);
807 EXPORT_SYMBOL_GPL(cpu_clock
);
809 #ifndef prepare_arch_switch
810 # define prepare_arch_switch(next) do { } while (0)
812 #ifndef finish_arch_switch
813 # define finish_arch_switch(prev) do { } while (0)
816 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
818 return rq
->curr
== p
;
821 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
822 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
824 return task_current(rq
, p
);
827 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
831 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
833 #ifdef CONFIG_DEBUG_SPINLOCK
834 /* this is a valid case when another task releases the spinlock */
835 rq
->lock
.owner
= current
;
838 * If we are tracking spinlock dependencies then we have to
839 * fix up the runqueue lock - which gets 'carried over' from
842 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
844 spin_unlock_irq(&rq
->lock
);
847 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
848 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
853 return task_current(rq
, p
);
857 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
861 * We can optimise this out completely for !SMP, because the
862 * SMP rebalancing from interrupt is the only thing that cares
867 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
868 spin_unlock_irq(&rq
->lock
);
870 spin_unlock(&rq
->lock
);
874 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
878 * After ->oncpu is cleared, the task can be moved to a different CPU.
879 * We must ensure this doesn't happen until the switch is completely
885 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
889 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
892 * __task_rq_lock - lock the runqueue a given task resides on.
893 * Must be called interrupts disabled.
895 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
899 struct rq
*rq
= task_rq(p
);
900 spin_lock(&rq
->lock
);
901 if (likely(rq
== task_rq(p
)))
903 spin_unlock(&rq
->lock
);
908 * task_rq_lock - lock the runqueue a given task resides on and disable
909 * interrupts. Note the ordering: we can safely lookup the task_rq without
910 * explicitly disabling preemption.
912 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
918 local_irq_save(*flags
);
920 spin_lock(&rq
->lock
);
921 if (likely(rq
== task_rq(p
)))
923 spin_unlock_irqrestore(&rq
->lock
, *flags
);
927 static void __task_rq_unlock(struct rq
*rq
)
930 spin_unlock(&rq
->lock
);
933 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
936 spin_unlock_irqrestore(&rq
->lock
, *flags
);
940 * this_rq_lock - lock this runqueue and disable interrupts.
942 static struct rq
*this_rq_lock(void)
949 spin_lock(&rq
->lock
);
955 * We are going deep-idle (irqs are disabled):
957 void sched_clock_idle_sleep_event(void)
959 struct rq
*rq
= cpu_rq(smp_processor_id());
961 spin_lock(&rq
->lock
);
962 __update_rq_clock(rq
);
963 spin_unlock(&rq
->lock
);
964 rq
->clock_deep_idle_events
++;
966 EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event
);
969 * We just idled delta nanoseconds (called with irqs disabled):
971 void sched_clock_idle_wakeup_event(u64 delta_ns
)
973 struct rq
*rq
= cpu_rq(smp_processor_id());
974 u64 now
= sched_clock();
976 rq
->idle_clock
+= delta_ns
;
978 * Override the previous timestamp and ignore all
979 * sched_clock() deltas that occured while we idled,
980 * and use the PM-provided delta_ns to advance the
983 spin_lock(&rq
->lock
);
984 rq
->prev_clock_raw
= now
;
985 rq
->clock
+= delta_ns
;
986 spin_unlock(&rq
->lock
);
987 touch_softlockup_watchdog();
989 EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event
);
991 static void __resched_task(struct task_struct
*p
, int tif_bit
);
993 static inline void resched_task(struct task_struct
*p
)
995 __resched_task(p
, TIF_NEED_RESCHED
);
998 #ifdef CONFIG_SCHED_HRTICK
1000 * Use HR-timers to deliver accurate preemption points.
1002 * Its all a bit involved since we cannot program an hrt while holding the
1003 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1006 * When we get rescheduled we reprogram the hrtick_timer outside of the
1009 static inline void resched_hrt(struct task_struct
*p
)
1011 __resched_task(p
, TIF_HRTICK_RESCHED
);
1014 static inline void resched_rq(struct rq
*rq
)
1016 unsigned long flags
;
1018 spin_lock_irqsave(&rq
->lock
, flags
);
1019 resched_task(rq
->curr
);
1020 spin_unlock_irqrestore(&rq
->lock
, flags
);
1024 HRTICK_SET
, /* re-programm hrtick_timer */
1025 HRTICK_RESET
, /* not a new slice */
1030 * - enabled by features
1031 * - hrtimer is actually high res
1033 static inline int hrtick_enabled(struct rq
*rq
)
1035 if (!sched_feat(HRTICK
))
1037 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1041 * Called to set the hrtick timer state.
1043 * called with rq->lock held and irqs disabled
1045 static void hrtick_start(struct rq
*rq
, u64 delay
, int reset
)
1047 assert_spin_locked(&rq
->lock
);
1050 * preempt at: now + delay
1053 ktime_add_ns(rq
->hrtick_timer
.base
->get_time(), delay
);
1055 * indicate we need to program the timer
1057 __set_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1059 __set_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1062 * New slices are called from the schedule path and don't need a
1063 * forced reschedule.
1066 resched_hrt(rq
->curr
);
1069 static void hrtick_clear(struct rq
*rq
)
1071 if (hrtimer_active(&rq
->hrtick_timer
))
1072 hrtimer_cancel(&rq
->hrtick_timer
);
1076 * Update the timer from the possible pending state.
1078 static void hrtick_set(struct rq
*rq
)
1082 unsigned long flags
;
1084 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1086 spin_lock_irqsave(&rq
->lock
, flags
);
1087 set
= __test_and_clear_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1088 reset
= __test_and_clear_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1089 time
= rq
->hrtick_expire
;
1090 clear_thread_flag(TIF_HRTICK_RESCHED
);
1091 spin_unlock_irqrestore(&rq
->lock
, flags
);
1094 hrtimer_start(&rq
->hrtick_timer
, time
, HRTIMER_MODE_ABS
);
1095 if (reset
&& !hrtimer_active(&rq
->hrtick_timer
))
1102 * High-resolution timer tick.
1103 * Runs from hardirq context with interrupts disabled.
1105 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1107 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1109 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1111 spin_lock(&rq
->lock
);
1112 __update_rq_clock(rq
);
1113 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1114 spin_unlock(&rq
->lock
);
1116 return HRTIMER_NORESTART
;
1119 static inline void init_rq_hrtick(struct rq
*rq
)
1121 rq
->hrtick_flags
= 0;
1122 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1123 rq
->hrtick_timer
.function
= hrtick
;
1124 rq
->hrtick_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1127 void hrtick_resched(void)
1130 unsigned long flags
;
1132 if (!test_thread_flag(TIF_HRTICK_RESCHED
))
1135 local_irq_save(flags
);
1136 rq
= cpu_rq(smp_processor_id());
1138 local_irq_restore(flags
);
1141 static inline void hrtick_clear(struct rq
*rq
)
1145 static inline void hrtick_set(struct rq
*rq
)
1149 static inline void init_rq_hrtick(struct rq
*rq
)
1153 void hrtick_resched(void)
1159 * resched_task - mark a task 'to be rescheduled now'.
1161 * On UP this means the setting of the need_resched flag, on SMP it
1162 * might also involve a cross-CPU call to trigger the scheduler on
1167 #ifndef tsk_is_polling
1168 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1171 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1175 assert_spin_locked(&task_rq(p
)->lock
);
1177 if (unlikely(test_tsk_thread_flag(p
, tif_bit
)))
1180 set_tsk_thread_flag(p
, tif_bit
);
1183 if (cpu
== smp_processor_id())
1186 /* NEED_RESCHED must be visible before we test polling */
1188 if (!tsk_is_polling(p
))
1189 smp_send_reschedule(cpu
);
1192 static void resched_cpu(int cpu
)
1194 struct rq
*rq
= cpu_rq(cpu
);
1195 unsigned long flags
;
1197 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1199 resched_task(cpu_curr(cpu
));
1200 spin_unlock_irqrestore(&rq
->lock
, flags
);
1205 * When add_timer_on() enqueues a timer into the timer wheel of an
1206 * idle CPU then this timer might expire before the next timer event
1207 * which is scheduled to wake up that CPU. In case of a completely
1208 * idle system the next event might even be infinite time into the
1209 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1210 * leaves the inner idle loop so the newly added timer is taken into
1211 * account when the CPU goes back to idle and evaluates the timer
1212 * wheel for the next timer event.
1214 void wake_up_idle_cpu(int cpu
)
1216 struct rq
*rq
= cpu_rq(cpu
);
1218 if (cpu
== smp_processor_id())
1222 * This is safe, as this function is called with the timer
1223 * wheel base lock of (cpu) held. When the CPU is on the way
1224 * to idle and has not yet set rq->curr to idle then it will
1225 * be serialized on the timer wheel base lock and take the new
1226 * timer into account automatically.
1228 if (rq
->curr
!= rq
->idle
)
1232 * We can set TIF_RESCHED on the idle task of the other CPU
1233 * lockless. The worst case is that the other CPU runs the
1234 * idle task through an additional NOOP schedule()
1236 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1238 /* NEED_RESCHED must be visible before we test polling */
1240 if (!tsk_is_polling(rq
->idle
))
1241 smp_send_reschedule(cpu
);
1246 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1248 assert_spin_locked(&task_rq(p
)->lock
);
1249 set_tsk_thread_flag(p
, tif_bit
);
1253 #if BITS_PER_LONG == 32
1254 # define WMULT_CONST (~0UL)
1256 # define WMULT_CONST (1UL << 32)
1259 #define WMULT_SHIFT 32
1262 * Shift right and round:
1264 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1266 static unsigned long
1267 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1268 struct load_weight
*lw
)
1272 if (unlikely(!lw
->inv_weight
))
1273 lw
->inv_weight
= (WMULT_CONST
-lw
->weight
/2) / (lw
->weight
+1);
1275 tmp
= (u64
)delta_exec
* weight
;
1277 * Check whether we'd overflow the 64-bit multiplication:
1279 if (unlikely(tmp
> WMULT_CONST
))
1280 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1283 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1285 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1288 static inline unsigned long
1289 calc_delta_fair(unsigned long delta_exec
, struct load_weight
*lw
)
1291 return calc_delta_mine(delta_exec
, NICE_0_LOAD
, lw
);
1294 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1300 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1307 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1308 * of tasks with abnormal "nice" values across CPUs the contribution that
1309 * each task makes to its run queue's load is weighted according to its
1310 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1311 * scaled version of the new time slice allocation that they receive on time
1315 #define WEIGHT_IDLEPRIO 2
1316 #define WMULT_IDLEPRIO (1 << 31)
1319 * Nice levels are multiplicative, with a gentle 10% change for every
1320 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1321 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1322 * that remained on nice 0.
1324 * The "10% effect" is relative and cumulative: from _any_ nice level,
1325 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1326 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1327 * If a task goes up by ~10% and another task goes down by ~10% then
1328 * the relative distance between them is ~25%.)
1330 static const int prio_to_weight
[40] = {
1331 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1332 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1333 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1334 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1335 /* 0 */ 1024, 820, 655, 526, 423,
1336 /* 5 */ 335, 272, 215, 172, 137,
1337 /* 10 */ 110, 87, 70, 56, 45,
1338 /* 15 */ 36, 29, 23, 18, 15,
1342 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1344 * In cases where the weight does not change often, we can use the
1345 * precalculated inverse to speed up arithmetics by turning divisions
1346 * into multiplications:
1348 static const u32 prio_to_wmult
[40] = {
1349 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1350 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1351 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1352 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1353 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1354 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1355 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1356 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1359 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1362 * runqueue iterator, to support SMP load-balancing between different
1363 * scheduling classes, without having to expose their internal data
1364 * structures to the load-balancing proper:
1366 struct rq_iterator
{
1368 struct task_struct
*(*start
)(void *);
1369 struct task_struct
*(*next
)(void *);
1373 static unsigned long
1374 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1375 unsigned long max_load_move
, struct sched_domain
*sd
,
1376 enum cpu_idle_type idle
, int *all_pinned
,
1377 int *this_best_prio
, struct rq_iterator
*iterator
);
1380 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1381 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1382 struct rq_iterator
*iterator
);
1385 #ifdef CONFIG_CGROUP_CPUACCT
1386 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1388 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1392 static unsigned long source_load(int cpu
, int type
);
1393 static unsigned long target_load(int cpu
, int type
);
1394 static unsigned long cpu_avg_load_per_task(int cpu
);
1395 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1396 #endif /* CONFIG_SMP */
1398 #include "sched_stats.h"
1399 #include "sched_idletask.c"
1400 #include "sched_fair.c"
1401 #include "sched_rt.c"
1402 #ifdef CONFIG_SCHED_DEBUG
1403 # include "sched_debug.c"
1406 #define sched_class_highest (&rt_sched_class)
1408 static inline void inc_load(struct rq
*rq
, const struct task_struct
*p
)
1410 update_load_add(&rq
->load
, p
->se
.load
.weight
);
1413 static inline void dec_load(struct rq
*rq
, const struct task_struct
*p
)
1415 update_load_sub(&rq
->load
, p
->se
.load
.weight
);
1418 static void inc_nr_running(struct task_struct
*p
, struct rq
*rq
)
1424 static void dec_nr_running(struct task_struct
*p
, struct rq
*rq
)
1430 static void set_load_weight(struct task_struct
*p
)
1432 if (task_has_rt_policy(p
)) {
1433 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1434 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1439 * SCHED_IDLE tasks get minimal weight:
1441 if (p
->policy
== SCHED_IDLE
) {
1442 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1443 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1447 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1448 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1451 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1453 sched_info_queued(p
);
1454 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1458 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1460 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1465 * __normal_prio - return the priority that is based on the static prio
1467 static inline int __normal_prio(struct task_struct
*p
)
1469 return p
->static_prio
;
1473 * Calculate the expected normal priority: i.e. priority
1474 * without taking RT-inheritance into account. Might be
1475 * boosted by interactivity modifiers. Changes upon fork,
1476 * setprio syscalls, and whenever the interactivity
1477 * estimator recalculates.
1479 static inline int normal_prio(struct task_struct
*p
)
1483 if (task_has_rt_policy(p
))
1484 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1486 prio
= __normal_prio(p
);
1491 * Calculate the current priority, i.e. the priority
1492 * taken into account by the scheduler. This value might
1493 * be boosted by RT tasks, or might be boosted by
1494 * interactivity modifiers. Will be RT if the task got
1495 * RT-boosted. If not then it returns p->normal_prio.
1497 static int effective_prio(struct task_struct
*p
)
1499 p
->normal_prio
= normal_prio(p
);
1501 * If we are RT tasks or we were boosted to RT priority,
1502 * keep the priority unchanged. Otherwise, update priority
1503 * to the normal priority:
1505 if (!rt_prio(p
->prio
))
1506 return p
->normal_prio
;
1511 * activate_task - move a task to the runqueue.
1513 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1515 if (task_contributes_to_load(p
))
1516 rq
->nr_uninterruptible
--;
1518 enqueue_task(rq
, p
, wakeup
);
1519 inc_nr_running(p
, rq
);
1523 * deactivate_task - remove a task from the runqueue.
1525 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1527 if (task_contributes_to_load(p
))
1528 rq
->nr_uninterruptible
++;
1530 dequeue_task(rq
, p
, sleep
);
1531 dec_nr_running(p
, rq
);
1535 * task_curr - is this task currently executing on a CPU?
1536 * @p: the task in question.
1538 inline int task_curr(const struct task_struct
*p
)
1540 return cpu_curr(task_cpu(p
)) == p
;
1543 /* Used instead of source_load when we know the type == 0 */
1544 unsigned long weighted_cpuload(const int cpu
)
1546 return cpu_rq(cpu
)->load
.weight
;
1549 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1551 set_task_rq(p
, cpu
);
1554 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1555 * successfuly executed on another CPU. We must ensure that updates of
1556 * per-task data have been completed by this moment.
1559 task_thread_info(p
)->cpu
= cpu
;
1563 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1564 const struct sched_class
*prev_class
,
1565 int oldprio
, int running
)
1567 if (prev_class
!= p
->sched_class
) {
1568 if (prev_class
->switched_from
)
1569 prev_class
->switched_from(rq
, p
, running
);
1570 p
->sched_class
->switched_to(rq
, p
, running
);
1572 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1578 * Is this task likely cache-hot:
1581 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1586 * Buddy candidates are cache hot:
1588 if (sched_feat(CACHE_HOT_BUDDY
) && (&p
->se
== cfs_rq_of(&p
->se
)->next
))
1591 if (p
->sched_class
!= &fair_sched_class
)
1594 if (sysctl_sched_migration_cost
== -1)
1596 if (sysctl_sched_migration_cost
== 0)
1599 delta
= now
- p
->se
.exec_start
;
1601 return delta
< (s64
)sysctl_sched_migration_cost
;
1605 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1607 int old_cpu
= task_cpu(p
);
1608 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1609 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1610 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1613 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1615 #ifdef CONFIG_SCHEDSTATS
1616 if (p
->se
.wait_start
)
1617 p
->se
.wait_start
-= clock_offset
;
1618 if (p
->se
.sleep_start
)
1619 p
->se
.sleep_start
-= clock_offset
;
1620 if (p
->se
.block_start
)
1621 p
->se
.block_start
-= clock_offset
;
1622 if (old_cpu
!= new_cpu
) {
1623 schedstat_inc(p
, se
.nr_migrations
);
1624 if (task_hot(p
, old_rq
->clock
, NULL
))
1625 schedstat_inc(p
, se
.nr_forced2_migrations
);
1628 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1629 new_cfsrq
->min_vruntime
;
1631 __set_task_cpu(p
, new_cpu
);
1634 struct migration_req
{
1635 struct list_head list
;
1637 struct task_struct
*task
;
1640 struct completion done
;
1644 * The task's runqueue lock must be held.
1645 * Returns true if you have to wait for migration thread.
1648 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1650 struct rq
*rq
= task_rq(p
);
1653 * If the task is not on a runqueue (and not running), then
1654 * it is sufficient to simply update the task's cpu field.
1656 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1657 set_task_cpu(p
, dest_cpu
);
1661 init_completion(&req
->done
);
1663 req
->dest_cpu
= dest_cpu
;
1664 list_add(&req
->list
, &rq
->migration_queue
);
1670 * wait_task_inactive - wait for a thread to unschedule.
1672 * The caller must ensure that the task *will* unschedule sometime soon,
1673 * else this function might spin for a *long* time. This function can't
1674 * be called with interrupts off, or it may introduce deadlock with
1675 * smp_call_function() if an IPI is sent by the same process we are
1676 * waiting to become inactive.
1678 void wait_task_inactive(struct task_struct
*p
)
1680 unsigned long flags
;
1686 * We do the initial early heuristics without holding
1687 * any task-queue locks at all. We'll only try to get
1688 * the runqueue lock when things look like they will
1694 * If the task is actively running on another CPU
1695 * still, just relax and busy-wait without holding
1698 * NOTE! Since we don't hold any locks, it's not
1699 * even sure that "rq" stays as the right runqueue!
1700 * But we don't care, since "task_running()" will
1701 * return false if the runqueue has changed and p
1702 * is actually now running somewhere else!
1704 while (task_running(rq
, p
))
1708 * Ok, time to look more closely! We need the rq
1709 * lock now, to be *sure*. If we're wrong, we'll
1710 * just go back and repeat.
1712 rq
= task_rq_lock(p
, &flags
);
1713 running
= task_running(rq
, p
);
1714 on_rq
= p
->se
.on_rq
;
1715 task_rq_unlock(rq
, &flags
);
1718 * Was it really running after all now that we
1719 * checked with the proper locks actually held?
1721 * Oops. Go back and try again..
1723 if (unlikely(running
)) {
1729 * It's not enough that it's not actively running,
1730 * it must be off the runqueue _entirely_, and not
1733 * So if it wa still runnable (but just not actively
1734 * running right now), it's preempted, and we should
1735 * yield - it could be a while.
1737 if (unlikely(on_rq
)) {
1738 schedule_timeout_uninterruptible(1);
1743 * Ahh, all good. It wasn't running, and it wasn't
1744 * runnable, which means that it will never become
1745 * running in the future either. We're all done!
1752 * kick_process - kick a running thread to enter/exit the kernel
1753 * @p: the to-be-kicked thread
1755 * Cause a process which is running on another CPU to enter
1756 * kernel-mode, without any delay. (to get signals handled.)
1758 * NOTE: this function doesnt have to take the runqueue lock,
1759 * because all it wants to ensure is that the remote task enters
1760 * the kernel. If the IPI races and the task has been migrated
1761 * to another CPU then no harm is done and the purpose has been
1764 void kick_process(struct task_struct
*p
)
1770 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1771 smp_send_reschedule(cpu
);
1776 * Return a low guess at the load of a migration-source cpu weighted
1777 * according to the scheduling class and "nice" value.
1779 * We want to under-estimate the load of migration sources, to
1780 * balance conservatively.
1782 static unsigned long source_load(int cpu
, int type
)
1784 struct rq
*rq
= cpu_rq(cpu
);
1785 unsigned long total
= weighted_cpuload(cpu
);
1790 return min(rq
->cpu_load
[type
-1], total
);
1794 * Return a high guess at the load of a migration-target cpu weighted
1795 * according to the scheduling class and "nice" value.
1797 static unsigned long target_load(int cpu
, int type
)
1799 struct rq
*rq
= cpu_rq(cpu
);
1800 unsigned long total
= weighted_cpuload(cpu
);
1805 return max(rq
->cpu_load
[type
-1], total
);
1809 * Return the average load per task on the cpu's run queue
1811 static unsigned long cpu_avg_load_per_task(int cpu
)
1813 struct rq
*rq
= cpu_rq(cpu
);
1814 unsigned long total
= weighted_cpuload(cpu
);
1815 unsigned long n
= rq
->nr_running
;
1817 return n
? total
/ n
: SCHED_LOAD_SCALE
;
1821 * find_idlest_group finds and returns the least busy CPU group within the
1824 static struct sched_group
*
1825 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
1827 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
1828 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
1829 int load_idx
= sd
->forkexec_idx
;
1830 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
1833 unsigned long load
, avg_load
;
1837 /* Skip over this group if it has no CPUs allowed */
1838 if (!cpus_intersects(group
->cpumask
, p
->cpus_allowed
))
1841 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
1843 /* Tally up the load of all CPUs in the group */
1846 for_each_cpu_mask(i
, group
->cpumask
) {
1847 /* Bias balancing toward cpus of our domain */
1849 load
= source_load(i
, load_idx
);
1851 load
= target_load(i
, load_idx
);
1856 /* Adjust by relative CPU power of the group */
1857 avg_load
= sg_div_cpu_power(group
,
1858 avg_load
* SCHED_LOAD_SCALE
);
1861 this_load
= avg_load
;
1863 } else if (avg_load
< min_load
) {
1864 min_load
= avg_load
;
1867 } while (group
= group
->next
, group
!= sd
->groups
);
1869 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
1875 * find_idlest_cpu - find the idlest cpu among the cpus in group.
1878 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
,
1881 unsigned long load
, min_load
= ULONG_MAX
;
1885 /* Traverse only the allowed CPUs */
1886 cpus_and(*tmp
, group
->cpumask
, p
->cpus_allowed
);
1888 for_each_cpu_mask(i
, *tmp
) {
1889 load
= weighted_cpuload(i
);
1891 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
1901 * sched_balance_self: balance the current task (running on cpu) in domains
1902 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
1905 * Balance, ie. select the least loaded group.
1907 * Returns the target CPU number, or the same CPU if no balancing is needed.
1909 * preempt must be disabled.
1911 static int sched_balance_self(int cpu
, int flag
)
1913 struct task_struct
*t
= current
;
1914 struct sched_domain
*tmp
, *sd
= NULL
;
1916 for_each_domain(cpu
, tmp
) {
1918 * If power savings logic is enabled for a domain, stop there.
1920 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
1922 if (tmp
->flags
& flag
)
1927 cpumask_t span
, tmpmask
;
1928 struct sched_group
*group
;
1929 int new_cpu
, weight
;
1931 if (!(sd
->flags
& flag
)) {
1937 group
= find_idlest_group(sd
, t
, cpu
);
1943 new_cpu
= find_idlest_cpu(group
, t
, cpu
, &tmpmask
);
1944 if (new_cpu
== -1 || new_cpu
== cpu
) {
1945 /* Now try balancing at a lower domain level of cpu */
1950 /* Now try balancing at a lower domain level of new_cpu */
1953 weight
= cpus_weight(span
);
1954 for_each_domain(cpu
, tmp
) {
1955 if (weight
<= cpus_weight(tmp
->span
))
1957 if (tmp
->flags
& flag
)
1960 /* while loop will break here if sd == NULL */
1966 #endif /* CONFIG_SMP */
1969 * try_to_wake_up - wake up a thread
1970 * @p: the to-be-woken-up thread
1971 * @state: the mask of task states that can be woken
1972 * @sync: do a synchronous wakeup?
1974 * Put it on the run-queue if it's not already there. The "current"
1975 * thread is always on the run-queue (except when the actual
1976 * re-schedule is in progress), and as such you're allowed to do
1977 * the simpler "current->state = TASK_RUNNING" to mark yourself
1978 * runnable without the overhead of this.
1980 * returns failure only if the task is already active.
1982 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
1984 int cpu
, orig_cpu
, this_cpu
, success
= 0;
1985 unsigned long flags
;
1989 if (!sched_feat(SYNC_WAKEUPS
))
1993 rq
= task_rq_lock(p
, &flags
);
1994 old_state
= p
->state
;
1995 if (!(old_state
& state
))
2003 this_cpu
= smp_processor_id();
2006 if (unlikely(task_running(rq
, p
)))
2009 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2010 if (cpu
!= orig_cpu
) {
2011 set_task_cpu(p
, cpu
);
2012 task_rq_unlock(rq
, &flags
);
2013 /* might preempt at this point */
2014 rq
= task_rq_lock(p
, &flags
);
2015 old_state
= p
->state
;
2016 if (!(old_state
& state
))
2021 this_cpu
= smp_processor_id();
2025 #ifdef CONFIG_SCHEDSTATS
2026 schedstat_inc(rq
, ttwu_count
);
2027 if (cpu
== this_cpu
)
2028 schedstat_inc(rq
, ttwu_local
);
2030 struct sched_domain
*sd
;
2031 for_each_domain(this_cpu
, sd
) {
2032 if (cpu_isset(cpu
, sd
->span
)) {
2033 schedstat_inc(sd
, ttwu_wake_remote
);
2041 #endif /* CONFIG_SMP */
2042 schedstat_inc(p
, se
.nr_wakeups
);
2044 schedstat_inc(p
, se
.nr_wakeups_sync
);
2045 if (orig_cpu
!= cpu
)
2046 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2047 if (cpu
== this_cpu
)
2048 schedstat_inc(p
, se
.nr_wakeups_local
);
2050 schedstat_inc(p
, se
.nr_wakeups_remote
);
2051 update_rq_clock(rq
);
2052 activate_task(rq
, p
, 1);
2056 check_preempt_curr(rq
, p
);
2058 p
->state
= TASK_RUNNING
;
2060 if (p
->sched_class
->task_wake_up
)
2061 p
->sched_class
->task_wake_up(rq
, p
);
2064 task_rq_unlock(rq
, &flags
);
2069 int wake_up_process(struct task_struct
*p
)
2071 return try_to_wake_up(p
, TASK_ALL
, 0);
2073 EXPORT_SYMBOL(wake_up_process
);
2075 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2077 return try_to_wake_up(p
, state
, 0);
2081 * Perform scheduler related setup for a newly forked process p.
2082 * p is forked by current.
2084 * __sched_fork() is basic setup used by init_idle() too:
2086 static void __sched_fork(struct task_struct
*p
)
2088 p
->se
.exec_start
= 0;
2089 p
->se
.sum_exec_runtime
= 0;
2090 p
->se
.prev_sum_exec_runtime
= 0;
2091 p
->se
.last_wakeup
= 0;
2092 p
->se
.avg_overlap
= 0;
2094 #ifdef CONFIG_SCHEDSTATS
2095 p
->se
.wait_start
= 0;
2096 p
->se
.sum_sleep_runtime
= 0;
2097 p
->se
.sleep_start
= 0;
2098 p
->se
.block_start
= 0;
2099 p
->se
.sleep_max
= 0;
2100 p
->se
.block_max
= 0;
2102 p
->se
.slice_max
= 0;
2106 INIT_LIST_HEAD(&p
->rt
.run_list
);
2109 #ifdef CONFIG_PREEMPT_NOTIFIERS
2110 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2114 * We mark the process as running here, but have not actually
2115 * inserted it onto the runqueue yet. This guarantees that
2116 * nobody will actually run it, and a signal or other external
2117 * event cannot wake it up and insert it on the runqueue either.
2119 p
->state
= TASK_RUNNING
;
2123 * fork()/clone()-time setup:
2125 void sched_fork(struct task_struct
*p
, int clone_flags
)
2127 int cpu
= get_cpu();
2132 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2134 set_task_cpu(p
, cpu
);
2137 * Make sure we do not leak PI boosting priority to the child:
2139 p
->prio
= current
->normal_prio
;
2140 if (!rt_prio(p
->prio
))
2141 p
->sched_class
= &fair_sched_class
;
2143 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2144 if (likely(sched_info_on()))
2145 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2147 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2150 #ifdef CONFIG_PREEMPT
2151 /* Want to start with kernel preemption disabled. */
2152 task_thread_info(p
)->preempt_count
= 1;
2158 * wake_up_new_task - wake up a newly created task for the first time.
2160 * This function will do some initial scheduler statistics housekeeping
2161 * that must be done for every newly created context, then puts the task
2162 * on the runqueue and wakes it.
2164 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2166 unsigned long flags
;
2169 rq
= task_rq_lock(p
, &flags
);
2170 BUG_ON(p
->state
!= TASK_RUNNING
);
2171 update_rq_clock(rq
);
2173 p
->prio
= effective_prio(p
);
2175 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2176 activate_task(rq
, p
, 0);
2179 * Let the scheduling class do new task startup
2180 * management (if any):
2182 p
->sched_class
->task_new(rq
, p
);
2183 inc_nr_running(p
, rq
);
2185 check_preempt_curr(rq
, p
);
2187 if (p
->sched_class
->task_wake_up
)
2188 p
->sched_class
->task_wake_up(rq
, p
);
2190 task_rq_unlock(rq
, &flags
);
2193 #ifdef CONFIG_PREEMPT_NOTIFIERS
2196 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2197 * @notifier: notifier struct to register
2199 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2201 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2203 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2206 * preempt_notifier_unregister - no longer interested in preemption notifications
2207 * @notifier: notifier struct to unregister
2209 * This is safe to call from within a preemption notifier.
2211 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2213 hlist_del(¬ifier
->link
);
2215 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2217 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2219 struct preempt_notifier
*notifier
;
2220 struct hlist_node
*node
;
2222 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2223 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2227 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2228 struct task_struct
*next
)
2230 struct preempt_notifier
*notifier
;
2231 struct hlist_node
*node
;
2233 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2234 notifier
->ops
->sched_out(notifier
, next
);
2239 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2244 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2245 struct task_struct
*next
)
2252 * prepare_task_switch - prepare to switch tasks
2253 * @rq: the runqueue preparing to switch
2254 * @prev: the current task that is being switched out
2255 * @next: the task we are going to switch to.
2257 * This is called with the rq lock held and interrupts off. It must
2258 * be paired with a subsequent finish_task_switch after the context
2261 * prepare_task_switch sets up locking and calls architecture specific
2265 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2266 struct task_struct
*next
)
2268 fire_sched_out_preempt_notifiers(prev
, next
);
2269 prepare_lock_switch(rq
, next
);
2270 prepare_arch_switch(next
);
2274 * finish_task_switch - clean up after a task-switch
2275 * @rq: runqueue associated with task-switch
2276 * @prev: the thread we just switched away from.
2278 * finish_task_switch must be called after the context switch, paired
2279 * with a prepare_task_switch call before the context switch.
2280 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2281 * and do any other architecture-specific cleanup actions.
2283 * Note that we may have delayed dropping an mm in context_switch(). If
2284 * so, we finish that here outside of the runqueue lock. (Doing it
2285 * with the lock held can cause deadlocks; see schedule() for
2288 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2289 __releases(rq
->lock
)
2291 struct mm_struct
*mm
= rq
->prev_mm
;
2297 * A task struct has one reference for the use as "current".
2298 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2299 * schedule one last time. The schedule call will never return, and
2300 * the scheduled task must drop that reference.
2301 * The test for TASK_DEAD must occur while the runqueue locks are
2302 * still held, otherwise prev could be scheduled on another cpu, die
2303 * there before we look at prev->state, and then the reference would
2305 * Manfred Spraul <manfred@colorfullife.com>
2307 prev_state
= prev
->state
;
2308 finish_arch_switch(prev
);
2309 finish_lock_switch(rq
, prev
);
2311 if (current
->sched_class
->post_schedule
)
2312 current
->sched_class
->post_schedule(rq
);
2315 fire_sched_in_preempt_notifiers(current
);
2318 if (unlikely(prev_state
== TASK_DEAD
)) {
2320 * Remove function-return probe instances associated with this
2321 * task and put them back on the free list.
2323 kprobe_flush_task(prev
);
2324 put_task_struct(prev
);
2329 * schedule_tail - first thing a freshly forked thread must call.
2330 * @prev: the thread we just switched away from.
2332 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2333 __releases(rq
->lock
)
2335 struct rq
*rq
= this_rq();
2337 finish_task_switch(rq
, prev
);
2338 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2339 /* In this case, finish_task_switch does not reenable preemption */
2342 if (current
->set_child_tid
)
2343 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2347 * context_switch - switch to the new MM and the new
2348 * thread's register state.
2351 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2352 struct task_struct
*next
)
2354 struct mm_struct
*mm
, *oldmm
;
2356 prepare_task_switch(rq
, prev
, next
);
2358 oldmm
= prev
->active_mm
;
2360 * For paravirt, this is coupled with an exit in switch_to to
2361 * combine the page table reload and the switch backend into
2364 arch_enter_lazy_cpu_mode();
2366 if (unlikely(!mm
)) {
2367 next
->active_mm
= oldmm
;
2368 atomic_inc(&oldmm
->mm_count
);
2369 enter_lazy_tlb(oldmm
, next
);
2371 switch_mm(oldmm
, mm
, next
);
2373 if (unlikely(!prev
->mm
)) {
2374 prev
->active_mm
= NULL
;
2375 rq
->prev_mm
= oldmm
;
2378 * Since the runqueue lock will be released by the next
2379 * task (which is an invalid locking op but in the case
2380 * of the scheduler it's an obvious special-case), so we
2381 * do an early lockdep release here:
2383 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2384 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2387 /* Here we just switch the register state and the stack. */
2388 switch_to(prev
, next
, prev
);
2392 * this_rq must be evaluated again because prev may have moved
2393 * CPUs since it called schedule(), thus the 'rq' on its stack
2394 * frame will be invalid.
2396 finish_task_switch(this_rq(), prev
);
2400 * nr_running, nr_uninterruptible and nr_context_switches:
2402 * externally visible scheduler statistics: current number of runnable
2403 * threads, current number of uninterruptible-sleeping threads, total
2404 * number of context switches performed since bootup.
2406 unsigned long nr_running(void)
2408 unsigned long i
, sum
= 0;
2410 for_each_online_cpu(i
)
2411 sum
+= cpu_rq(i
)->nr_running
;
2416 unsigned long nr_uninterruptible(void)
2418 unsigned long i
, sum
= 0;
2420 for_each_possible_cpu(i
)
2421 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2424 * Since we read the counters lockless, it might be slightly
2425 * inaccurate. Do not allow it to go below zero though:
2427 if (unlikely((long)sum
< 0))
2433 unsigned long long nr_context_switches(void)
2436 unsigned long long sum
= 0;
2438 for_each_possible_cpu(i
)
2439 sum
+= cpu_rq(i
)->nr_switches
;
2444 unsigned long nr_iowait(void)
2446 unsigned long i
, sum
= 0;
2448 for_each_possible_cpu(i
)
2449 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2454 unsigned long nr_active(void)
2456 unsigned long i
, running
= 0, uninterruptible
= 0;
2458 for_each_online_cpu(i
) {
2459 running
+= cpu_rq(i
)->nr_running
;
2460 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2463 if (unlikely((long)uninterruptible
< 0))
2464 uninterruptible
= 0;
2466 return running
+ uninterruptible
;
2470 * Update rq->cpu_load[] statistics. This function is usually called every
2471 * scheduler tick (TICK_NSEC).
2473 static void update_cpu_load(struct rq
*this_rq
)
2475 unsigned long this_load
= this_rq
->load
.weight
;
2478 this_rq
->nr_load_updates
++;
2480 /* Update our load: */
2481 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2482 unsigned long old_load
, new_load
;
2484 /* scale is effectively 1 << i now, and >> i divides by scale */
2486 old_load
= this_rq
->cpu_load
[i
];
2487 new_load
= this_load
;
2489 * Round up the averaging division if load is increasing. This
2490 * prevents us from getting stuck on 9 if the load is 10, for
2493 if (new_load
> old_load
)
2494 new_load
+= scale
-1;
2495 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2502 * double_rq_lock - safely lock two runqueues
2504 * Note this does not disable interrupts like task_rq_lock,
2505 * you need to do so manually before calling.
2507 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2508 __acquires(rq1
->lock
)
2509 __acquires(rq2
->lock
)
2511 BUG_ON(!irqs_disabled());
2513 spin_lock(&rq1
->lock
);
2514 __acquire(rq2
->lock
); /* Fake it out ;) */
2517 spin_lock(&rq1
->lock
);
2518 spin_lock(&rq2
->lock
);
2520 spin_lock(&rq2
->lock
);
2521 spin_lock(&rq1
->lock
);
2524 update_rq_clock(rq1
);
2525 update_rq_clock(rq2
);
2529 * double_rq_unlock - safely unlock two runqueues
2531 * Note this does not restore interrupts like task_rq_unlock,
2532 * you need to do so manually after calling.
2534 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2535 __releases(rq1
->lock
)
2536 __releases(rq2
->lock
)
2538 spin_unlock(&rq1
->lock
);
2540 spin_unlock(&rq2
->lock
);
2542 __release(rq2
->lock
);
2546 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2548 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
2549 __releases(this_rq
->lock
)
2550 __acquires(busiest
->lock
)
2551 __acquires(this_rq
->lock
)
2555 if (unlikely(!irqs_disabled())) {
2556 /* printk() doesn't work good under rq->lock */
2557 spin_unlock(&this_rq
->lock
);
2560 if (unlikely(!spin_trylock(&busiest
->lock
))) {
2561 if (busiest
< this_rq
) {
2562 spin_unlock(&this_rq
->lock
);
2563 spin_lock(&busiest
->lock
);
2564 spin_lock(&this_rq
->lock
);
2567 spin_lock(&busiest
->lock
);
2573 * If dest_cpu is allowed for this process, migrate the task to it.
2574 * This is accomplished by forcing the cpu_allowed mask to only
2575 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2576 * the cpu_allowed mask is restored.
2578 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2580 struct migration_req req
;
2581 unsigned long flags
;
2584 rq
= task_rq_lock(p
, &flags
);
2585 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
)
2586 || unlikely(cpu_is_offline(dest_cpu
)))
2589 /* force the process onto the specified CPU */
2590 if (migrate_task(p
, dest_cpu
, &req
)) {
2591 /* Need to wait for migration thread (might exit: take ref). */
2592 struct task_struct
*mt
= rq
->migration_thread
;
2594 get_task_struct(mt
);
2595 task_rq_unlock(rq
, &flags
);
2596 wake_up_process(mt
);
2597 put_task_struct(mt
);
2598 wait_for_completion(&req
.done
);
2603 task_rq_unlock(rq
, &flags
);
2607 * sched_exec - execve() is a valuable balancing opportunity, because at
2608 * this point the task has the smallest effective memory and cache footprint.
2610 void sched_exec(void)
2612 int new_cpu
, this_cpu
= get_cpu();
2613 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2615 if (new_cpu
!= this_cpu
)
2616 sched_migrate_task(current
, new_cpu
);
2620 * pull_task - move a task from a remote runqueue to the local runqueue.
2621 * Both runqueues must be locked.
2623 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2624 struct rq
*this_rq
, int this_cpu
)
2626 deactivate_task(src_rq
, p
, 0);
2627 set_task_cpu(p
, this_cpu
);
2628 activate_task(this_rq
, p
, 0);
2630 * Note that idle threads have a prio of MAX_PRIO, for this test
2631 * to be always true for them.
2633 check_preempt_curr(this_rq
, p
);
2637 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2640 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2641 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2645 * We do not migrate tasks that are:
2646 * 1) running (obviously), or
2647 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2648 * 3) are cache-hot on their current CPU.
2650 if (!cpu_isset(this_cpu
, p
->cpus_allowed
)) {
2651 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
2656 if (task_running(rq
, p
)) {
2657 schedstat_inc(p
, se
.nr_failed_migrations_running
);
2662 * Aggressive migration if:
2663 * 1) task is cache cold, or
2664 * 2) too many balance attempts have failed.
2667 if (!task_hot(p
, rq
->clock
, sd
) ||
2668 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
2669 #ifdef CONFIG_SCHEDSTATS
2670 if (task_hot(p
, rq
->clock
, sd
)) {
2671 schedstat_inc(sd
, lb_hot_gained
[idle
]);
2672 schedstat_inc(p
, se
.nr_forced_migrations
);
2678 if (task_hot(p
, rq
->clock
, sd
)) {
2679 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
2685 static unsigned long
2686 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2687 unsigned long max_load_move
, struct sched_domain
*sd
,
2688 enum cpu_idle_type idle
, int *all_pinned
,
2689 int *this_best_prio
, struct rq_iterator
*iterator
)
2691 int loops
= 0, pulled
= 0, pinned
= 0, skip_for_load
;
2692 struct task_struct
*p
;
2693 long rem_load_move
= max_load_move
;
2695 if (max_load_move
== 0)
2701 * Start the load-balancing iterator:
2703 p
= iterator
->start(iterator
->arg
);
2705 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
2708 * To help distribute high priority tasks across CPUs we don't
2709 * skip a task if it will be the highest priority task (i.e. smallest
2710 * prio value) on its new queue regardless of its load weight
2712 skip_for_load
= (p
->se
.load
.weight
>> 1) > rem_load_move
+
2713 SCHED_LOAD_SCALE_FUZZ
;
2714 if ((skip_for_load
&& p
->prio
>= *this_best_prio
) ||
2715 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2716 p
= iterator
->next(iterator
->arg
);
2720 pull_task(busiest
, p
, this_rq
, this_cpu
);
2722 rem_load_move
-= p
->se
.load
.weight
;
2725 * We only want to steal up to the prescribed amount of weighted load.
2727 if (rem_load_move
> 0) {
2728 if (p
->prio
< *this_best_prio
)
2729 *this_best_prio
= p
->prio
;
2730 p
= iterator
->next(iterator
->arg
);
2735 * Right now, this is one of only two places pull_task() is called,
2736 * so we can safely collect pull_task() stats here rather than
2737 * inside pull_task().
2739 schedstat_add(sd
, lb_gained
[idle
], pulled
);
2742 *all_pinned
= pinned
;
2744 return max_load_move
- rem_load_move
;
2748 * move_tasks tries to move up to max_load_move weighted load from busiest to
2749 * this_rq, as part of a balancing operation within domain "sd".
2750 * Returns 1 if successful and 0 otherwise.
2752 * Called with both runqueues locked.
2754 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2755 unsigned long max_load_move
,
2756 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2759 const struct sched_class
*class = sched_class_highest
;
2760 unsigned long total_load_moved
= 0;
2761 int this_best_prio
= this_rq
->curr
->prio
;
2765 class->load_balance(this_rq
, this_cpu
, busiest
,
2766 max_load_move
- total_load_moved
,
2767 sd
, idle
, all_pinned
, &this_best_prio
);
2768 class = class->next
;
2769 } while (class && max_load_move
> total_load_moved
);
2771 return total_load_moved
> 0;
2775 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2776 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2777 struct rq_iterator
*iterator
)
2779 struct task_struct
*p
= iterator
->start(iterator
->arg
);
2783 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2784 pull_task(busiest
, p
, this_rq
, this_cpu
);
2786 * Right now, this is only the second place pull_task()
2787 * is called, so we can safely collect pull_task()
2788 * stats here rather than inside pull_task().
2790 schedstat_inc(sd
, lb_gained
[idle
]);
2794 p
= iterator
->next(iterator
->arg
);
2801 * move_one_task tries to move exactly one task from busiest to this_rq, as
2802 * part of active balancing operations within "domain".
2803 * Returns 1 if successful and 0 otherwise.
2805 * Called with both runqueues locked.
2807 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2808 struct sched_domain
*sd
, enum cpu_idle_type idle
)
2810 const struct sched_class
*class;
2812 for (class = sched_class_highest
; class; class = class->next
)
2813 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
2820 * find_busiest_group finds and returns the busiest CPU group within the
2821 * domain. It calculates and returns the amount of weighted load which
2822 * should be moved to restore balance via the imbalance parameter.
2824 static struct sched_group
*
2825 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
2826 unsigned long *imbalance
, enum cpu_idle_type idle
,
2827 int *sd_idle
, const cpumask_t
*cpus
, int *balance
)
2829 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2830 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
2831 unsigned long max_pull
;
2832 unsigned long busiest_load_per_task
, busiest_nr_running
;
2833 unsigned long this_load_per_task
, this_nr_running
;
2834 int load_idx
, group_imb
= 0;
2835 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2836 int power_savings_balance
= 1;
2837 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
2838 unsigned long min_nr_running
= ULONG_MAX
;
2839 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
2842 max_load
= this_load
= total_load
= total_pwr
= 0;
2843 busiest_load_per_task
= busiest_nr_running
= 0;
2844 this_load_per_task
= this_nr_running
= 0;
2845 if (idle
== CPU_NOT_IDLE
)
2846 load_idx
= sd
->busy_idx
;
2847 else if (idle
== CPU_NEWLY_IDLE
)
2848 load_idx
= sd
->newidle_idx
;
2850 load_idx
= sd
->idle_idx
;
2853 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
2856 int __group_imb
= 0;
2857 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
2858 unsigned long sum_nr_running
, sum_weighted_load
;
2860 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
2863 balance_cpu
= first_cpu(group
->cpumask
);
2865 /* Tally up the load of all CPUs in the group */
2866 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
2868 min_cpu_load
= ~0UL;
2870 for_each_cpu_mask(i
, group
->cpumask
) {
2873 if (!cpu_isset(i
, *cpus
))
2878 if (*sd_idle
&& rq
->nr_running
)
2881 /* Bias balancing toward cpus of our domain */
2883 if (idle_cpu(i
) && !first_idle_cpu
) {
2888 load
= target_load(i
, load_idx
);
2890 load
= source_load(i
, load_idx
);
2891 if (load
> max_cpu_load
)
2892 max_cpu_load
= load
;
2893 if (min_cpu_load
> load
)
2894 min_cpu_load
= load
;
2898 sum_nr_running
+= rq
->nr_running
;
2899 sum_weighted_load
+= weighted_cpuload(i
);
2903 * First idle cpu or the first cpu(busiest) in this sched group
2904 * is eligible for doing load balancing at this and above
2905 * domains. In the newly idle case, we will allow all the cpu's
2906 * to do the newly idle load balance.
2908 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
2909 balance_cpu
!= this_cpu
&& balance
) {
2914 total_load
+= avg_load
;
2915 total_pwr
+= group
->__cpu_power
;
2917 /* Adjust by relative CPU power of the group */
2918 avg_load
= sg_div_cpu_power(group
,
2919 avg_load
* SCHED_LOAD_SCALE
);
2921 if ((max_cpu_load
- min_cpu_load
) > SCHED_LOAD_SCALE
)
2924 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
2927 this_load
= avg_load
;
2929 this_nr_running
= sum_nr_running
;
2930 this_load_per_task
= sum_weighted_load
;
2931 } else if (avg_load
> max_load
&&
2932 (sum_nr_running
> group_capacity
|| __group_imb
)) {
2933 max_load
= avg_load
;
2935 busiest_nr_running
= sum_nr_running
;
2936 busiest_load_per_task
= sum_weighted_load
;
2937 group_imb
= __group_imb
;
2940 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2942 * Busy processors will not participate in power savings
2945 if (idle
== CPU_NOT_IDLE
||
2946 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
2950 * If the local group is idle or completely loaded
2951 * no need to do power savings balance at this domain
2953 if (local_group
&& (this_nr_running
>= group_capacity
||
2955 power_savings_balance
= 0;
2958 * If a group is already running at full capacity or idle,
2959 * don't include that group in power savings calculations
2961 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
2966 * Calculate the group which has the least non-idle load.
2967 * This is the group from where we need to pick up the load
2970 if ((sum_nr_running
< min_nr_running
) ||
2971 (sum_nr_running
== min_nr_running
&&
2972 first_cpu(group
->cpumask
) <
2973 first_cpu(group_min
->cpumask
))) {
2975 min_nr_running
= sum_nr_running
;
2976 min_load_per_task
= sum_weighted_load
/
2981 * Calculate the group which is almost near its
2982 * capacity but still has some space to pick up some load
2983 * from other group and save more power
2985 if (sum_nr_running
<= group_capacity
- 1) {
2986 if (sum_nr_running
> leader_nr_running
||
2987 (sum_nr_running
== leader_nr_running
&&
2988 first_cpu(group
->cpumask
) >
2989 first_cpu(group_leader
->cpumask
))) {
2990 group_leader
= group
;
2991 leader_nr_running
= sum_nr_running
;
2996 group
= group
->next
;
2997 } while (group
!= sd
->groups
);
2999 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3002 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3004 if (this_load
>= avg_load
||
3005 100*max_load
<= sd
->imbalance_pct
*this_load
)
3008 busiest_load_per_task
/= busiest_nr_running
;
3010 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3013 * We're trying to get all the cpus to the average_load, so we don't
3014 * want to push ourselves above the average load, nor do we wish to
3015 * reduce the max loaded cpu below the average load, as either of these
3016 * actions would just result in more rebalancing later, and ping-pong
3017 * tasks around. Thus we look for the minimum possible imbalance.
3018 * Negative imbalances (*we* are more loaded than anyone else) will
3019 * be counted as no imbalance for these purposes -- we can't fix that
3020 * by pulling tasks to us. Be careful of negative numbers as they'll
3021 * appear as very large values with unsigned longs.
3023 if (max_load
<= busiest_load_per_task
)
3027 * In the presence of smp nice balancing, certain scenarios can have
3028 * max load less than avg load(as we skip the groups at or below
3029 * its cpu_power, while calculating max_load..)
3031 if (max_load
< avg_load
) {
3033 goto small_imbalance
;
3036 /* Don't want to pull so many tasks that a group would go idle */
3037 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3039 /* How much load to actually move to equalise the imbalance */
3040 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3041 (avg_load
- this_load
) * this->__cpu_power
)
3045 * if *imbalance is less than the average load per runnable task
3046 * there is no gaurantee that any tasks will be moved so we'll have
3047 * a think about bumping its value to force at least one task to be
3050 if (*imbalance
< busiest_load_per_task
) {
3051 unsigned long tmp
, pwr_now
, pwr_move
;
3055 pwr_move
= pwr_now
= 0;
3057 if (this_nr_running
) {
3058 this_load_per_task
/= this_nr_running
;
3059 if (busiest_load_per_task
> this_load_per_task
)
3062 this_load_per_task
= SCHED_LOAD_SCALE
;
3064 if (max_load
- this_load
+ SCHED_LOAD_SCALE_FUZZ
>=
3065 busiest_load_per_task
* imbn
) {
3066 *imbalance
= busiest_load_per_task
;
3071 * OK, we don't have enough imbalance to justify moving tasks,
3072 * however we may be able to increase total CPU power used by
3076 pwr_now
+= busiest
->__cpu_power
*
3077 min(busiest_load_per_task
, max_load
);
3078 pwr_now
+= this->__cpu_power
*
3079 min(this_load_per_task
, this_load
);
3080 pwr_now
/= SCHED_LOAD_SCALE
;
3082 /* Amount of load we'd subtract */
3083 tmp
= sg_div_cpu_power(busiest
,
3084 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3086 pwr_move
+= busiest
->__cpu_power
*
3087 min(busiest_load_per_task
, max_load
- tmp
);
3089 /* Amount of load we'd add */
3090 if (max_load
* busiest
->__cpu_power
<
3091 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3092 tmp
= sg_div_cpu_power(this,
3093 max_load
* busiest
->__cpu_power
);
3095 tmp
= sg_div_cpu_power(this,
3096 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3097 pwr_move
+= this->__cpu_power
*
3098 min(this_load_per_task
, this_load
+ tmp
);
3099 pwr_move
/= SCHED_LOAD_SCALE
;
3101 /* Move if we gain throughput */
3102 if (pwr_move
> pwr_now
)
3103 *imbalance
= busiest_load_per_task
;
3109 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3110 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3113 if (this == group_leader
&& group_leader
!= group_min
) {
3114 *imbalance
= min_load_per_task
;
3124 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3127 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3128 unsigned long imbalance
, const cpumask_t
*cpus
)
3130 struct rq
*busiest
= NULL
, *rq
;
3131 unsigned long max_load
= 0;
3134 for_each_cpu_mask(i
, group
->cpumask
) {
3137 if (!cpu_isset(i
, *cpus
))
3141 wl
= weighted_cpuload(i
);
3143 if (rq
->nr_running
== 1 && wl
> imbalance
)
3146 if (wl
> max_load
) {
3156 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3157 * so long as it is large enough.
3159 #define MAX_PINNED_INTERVAL 512
3162 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3163 * tasks if there is an imbalance.
3165 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3166 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3167 int *balance
, cpumask_t
*cpus
)
3169 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3170 struct sched_group
*group
;
3171 unsigned long imbalance
;
3173 unsigned long flags
;
3178 * When power savings policy is enabled for the parent domain, idle
3179 * sibling can pick up load irrespective of busy siblings. In this case,
3180 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3181 * portraying it as CPU_NOT_IDLE.
3183 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3184 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3187 schedstat_inc(sd
, lb_count
[idle
]);
3190 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3197 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3201 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3203 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3207 BUG_ON(busiest
== this_rq
);
3209 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3212 if (busiest
->nr_running
> 1) {
3214 * Attempt to move tasks. If find_busiest_group has found
3215 * an imbalance but busiest->nr_running <= 1, the group is
3216 * still unbalanced. ld_moved simply stays zero, so it is
3217 * correctly treated as an imbalance.
3219 local_irq_save(flags
);
3220 double_rq_lock(this_rq
, busiest
);
3221 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3222 imbalance
, sd
, idle
, &all_pinned
);
3223 double_rq_unlock(this_rq
, busiest
);
3224 local_irq_restore(flags
);
3227 * some other cpu did the load balance for us.
3229 if (ld_moved
&& this_cpu
!= smp_processor_id())
3230 resched_cpu(this_cpu
);
3232 /* All tasks on this runqueue were pinned by CPU affinity */
3233 if (unlikely(all_pinned
)) {
3234 cpu_clear(cpu_of(busiest
), *cpus
);
3235 if (!cpus_empty(*cpus
))
3242 schedstat_inc(sd
, lb_failed
[idle
]);
3243 sd
->nr_balance_failed
++;
3245 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3247 spin_lock_irqsave(&busiest
->lock
, flags
);
3249 /* don't kick the migration_thread, if the curr
3250 * task on busiest cpu can't be moved to this_cpu
3252 if (!cpu_isset(this_cpu
, busiest
->curr
->cpus_allowed
)) {
3253 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3255 goto out_one_pinned
;
3258 if (!busiest
->active_balance
) {
3259 busiest
->active_balance
= 1;
3260 busiest
->push_cpu
= this_cpu
;
3263 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3265 wake_up_process(busiest
->migration_thread
);
3268 * We've kicked active balancing, reset the failure
3271 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3274 sd
->nr_balance_failed
= 0;
3276 if (likely(!active_balance
)) {
3277 /* We were unbalanced, so reset the balancing interval */
3278 sd
->balance_interval
= sd
->min_interval
;
3281 * If we've begun active balancing, start to back off. This
3282 * case may not be covered by the all_pinned logic if there
3283 * is only 1 task on the busy runqueue (because we don't call
3286 if (sd
->balance_interval
< sd
->max_interval
)
3287 sd
->balance_interval
*= 2;
3290 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3291 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3296 schedstat_inc(sd
, lb_balanced
[idle
]);
3298 sd
->nr_balance_failed
= 0;
3301 /* tune up the balancing interval */
3302 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3303 (sd
->balance_interval
< sd
->max_interval
))
3304 sd
->balance_interval
*= 2;
3306 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3307 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3313 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3314 * tasks if there is an imbalance.
3316 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3317 * this_rq is locked.
3320 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3323 struct sched_group
*group
;
3324 struct rq
*busiest
= NULL
;
3325 unsigned long imbalance
;
3333 * When power savings policy is enabled for the parent domain, idle
3334 * sibling can pick up load irrespective of busy siblings. In this case,
3335 * let the state of idle sibling percolate up as IDLE, instead of
3336 * portraying it as CPU_NOT_IDLE.
3338 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3339 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3342 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3344 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3345 &sd_idle
, cpus
, NULL
);
3347 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3351 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3353 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3357 BUG_ON(busiest
== this_rq
);
3359 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3362 if (busiest
->nr_running
> 1) {
3363 /* Attempt to move tasks */
3364 double_lock_balance(this_rq
, busiest
);
3365 /* this_rq->clock is already updated */
3366 update_rq_clock(busiest
);
3367 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3368 imbalance
, sd
, CPU_NEWLY_IDLE
,
3370 spin_unlock(&busiest
->lock
);
3372 if (unlikely(all_pinned
)) {
3373 cpu_clear(cpu_of(busiest
), *cpus
);
3374 if (!cpus_empty(*cpus
))
3380 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3381 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3382 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3385 sd
->nr_balance_failed
= 0;
3390 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3391 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3392 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3394 sd
->nr_balance_failed
= 0;
3400 * idle_balance is called by schedule() if this_cpu is about to become
3401 * idle. Attempts to pull tasks from other CPUs.
3403 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3405 struct sched_domain
*sd
;
3406 int pulled_task
= -1;
3407 unsigned long next_balance
= jiffies
+ HZ
;
3410 for_each_domain(this_cpu
, sd
) {
3411 unsigned long interval
;
3413 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3416 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3417 /* If we've pulled tasks over stop searching: */
3418 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3421 interval
= msecs_to_jiffies(sd
->balance_interval
);
3422 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3423 next_balance
= sd
->last_balance
+ interval
;
3427 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3429 * We are going idle. next_balance may be set based on
3430 * a busy processor. So reset next_balance.
3432 this_rq
->next_balance
= next_balance
;
3437 * active_load_balance is run by migration threads. It pushes running tasks
3438 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3439 * running on each physical CPU where possible, and avoids physical /
3440 * logical imbalances.
3442 * Called with busiest_rq locked.
3444 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3446 int target_cpu
= busiest_rq
->push_cpu
;
3447 struct sched_domain
*sd
;
3448 struct rq
*target_rq
;
3450 /* Is there any task to move? */
3451 if (busiest_rq
->nr_running
<= 1)
3454 target_rq
= cpu_rq(target_cpu
);
3457 * This condition is "impossible", if it occurs
3458 * we need to fix it. Originally reported by
3459 * Bjorn Helgaas on a 128-cpu setup.
3461 BUG_ON(busiest_rq
== target_rq
);
3463 /* move a task from busiest_rq to target_rq */
3464 double_lock_balance(busiest_rq
, target_rq
);
3465 update_rq_clock(busiest_rq
);
3466 update_rq_clock(target_rq
);
3468 /* Search for an sd spanning us and the target CPU. */
3469 for_each_domain(target_cpu
, sd
) {
3470 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3471 cpu_isset(busiest_cpu
, sd
->span
))
3476 schedstat_inc(sd
, alb_count
);
3478 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3480 schedstat_inc(sd
, alb_pushed
);
3482 schedstat_inc(sd
, alb_failed
);
3484 spin_unlock(&target_rq
->lock
);
3489 atomic_t load_balancer
;
3491 } nohz ____cacheline_aligned
= {
3492 .load_balancer
= ATOMIC_INIT(-1),
3493 .cpu_mask
= CPU_MASK_NONE
,
3497 * This routine will try to nominate the ilb (idle load balancing)
3498 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3499 * load balancing on behalf of all those cpus. If all the cpus in the system
3500 * go into this tickless mode, then there will be no ilb owner (as there is
3501 * no need for one) and all the cpus will sleep till the next wakeup event
3504 * For the ilb owner, tick is not stopped. And this tick will be used
3505 * for idle load balancing. ilb owner will still be part of
3508 * While stopping the tick, this cpu will become the ilb owner if there
3509 * is no other owner. And will be the owner till that cpu becomes busy
3510 * or if all cpus in the system stop their ticks at which point
3511 * there is no need for ilb owner.
3513 * When the ilb owner becomes busy, it nominates another owner, during the
3514 * next busy scheduler_tick()
3516 int select_nohz_load_balancer(int stop_tick
)
3518 int cpu
= smp_processor_id();
3521 cpu_set(cpu
, nohz
.cpu_mask
);
3522 cpu_rq(cpu
)->in_nohz_recently
= 1;
3525 * If we are going offline and still the leader, give up!
3527 if (cpu_is_offline(cpu
) &&
3528 atomic_read(&nohz
.load_balancer
) == cpu
) {
3529 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3534 /* time for ilb owner also to sleep */
3535 if (cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3536 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3537 atomic_set(&nohz
.load_balancer
, -1);
3541 if (atomic_read(&nohz
.load_balancer
) == -1) {
3542 /* make me the ilb owner */
3543 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
3545 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
3548 if (!cpu_isset(cpu
, nohz
.cpu_mask
))
3551 cpu_clear(cpu
, nohz
.cpu_mask
);
3553 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3554 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3561 static DEFINE_SPINLOCK(balancing
);
3564 * It checks each scheduling domain to see if it is due to be balanced,
3565 * and initiates a balancing operation if so.
3567 * Balancing parameters are set up in arch_init_sched_domains.
3569 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
3572 struct rq
*rq
= cpu_rq(cpu
);
3573 unsigned long interval
;
3574 struct sched_domain
*sd
;
3575 /* Earliest time when we have to do rebalance again */
3576 unsigned long next_balance
= jiffies
+ 60*HZ
;
3577 int update_next_balance
= 0;
3580 for_each_domain(cpu
, sd
) {
3581 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3584 interval
= sd
->balance_interval
;
3585 if (idle
!= CPU_IDLE
)
3586 interval
*= sd
->busy_factor
;
3588 /* scale ms to jiffies */
3589 interval
= msecs_to_jiffies(interval
);
3590 if (unlikely(!interval
))
3592 if (interval
> HZ
*NR_CPUS
/10)
3593 interval
= HZ
*NR_CPUS
/10;
3596 if (sd
->flags
& SD_SERIALIZE
) {
3597 if (!spin_trylock(&balancing
))
3601 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
3602 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, &tmp
)) {
3604 * We've pulled tasks over so either we're no
3605 * longer idle, or one of our SMT siblings is
3608 idle
= CPU_NOT_IDLE
;
3610 sd
->last_balance
= jiffies
;
3612 if (sd
->flags
& SD_SERIALIZE
)
3613 spin_unlock(&balancing
);
3615 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
3616 next_balance
= sd
->last_balance
+ interval
;
3617 update_next_balance
= 1;
3621 * Stop the load balance at this level. There is another
3622 * CPU in our sched group which is doing load balancing more
3630 * next_balance will be updated only when there is a need.
3631 * When the cpu is attached to null domain for ex, it will not be
3634 if (likely(update_next_balance
))
3635 rq
->next_balance
= next_balance
;
3639 * run_rebalance_domains is triggered when needed from the scheduler tick.
3640 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3641 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3643 static void run_rebalance_domains(struct softirq_action
*h
)
3645 int this_cpu
= smp_processor_id();
3646 struct rq
*this_rq
= cpu_rq(this_cpu
);
3647 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
3648 CPU_IDLE
: CPU_NOT_IDLE
;
3650 rebalance_domains(this_cpu
, idle
);
3654 * If this cpu is the owner for idle load balancing, then do the
3655 * balancing on behalf of the other idle cpus whose ticks are
3658 if (this_rq
->idle_at_tick
&&
3659 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
3660 cpumask_t cpus
= nohz
.cpu_mask
;
3664 cpu_clear(this_cpu
, cpus
);
3665 for_each_cpu_mask(balance_cpu
, cpus
) {
3667 * If this cpu gets work to do, stop the load balancing
3668 * work being done for other cpus. Next load
3669 * balancing owner will pick it up.
3674 rebalance_domains(balance_cpu
, CPU_IDLE
);
3676 rq
= cpu_rq(balance_cpu
);
3677 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
3678 this_rq
->next_balance
= rq
->next_balance
;
3685 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3687 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3688 * idle load balancing owner or decide to stop the periodic load balancing,
3689 * if the whole system is idle.
3691 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
3695 * If we were in the nohz mode recently and busy at the current
3696 * scheduler tick, then check if we need to nominate new idle
3699 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
3700 rq
->in_nohz_recently
= 0;
3702 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
3703 cpu_clear(cpu
, nohz
.cpu_mask
);
3704 atomic_set(&nohz
.load_balancer
, -1);
3707 if (atomic_read(&nohz
.load_balancer
) == -1) {
3709 * simple selection for now: Nominate the
3710 * first cpu in the nohz list to be the next
3713 * TBD: Traverse the sched domains and nominate
3714 * the nearest cpu in the nohz.cpu_mask.
3716 int ilb
= first_cpu(nohz
.cpu_mask
);
3718 if (ilb
< nr_cpu_ids
)
3724 * If this cpu is idle and doing idle load balancing for all the
3725 * cpus with ticks stopped, is it time for that to stop?
3727 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
3728 cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3734 * If this cpu is idle and the idle load balancing is done by
3735 * someone else, then no need raise the SCHED_SOFTIRQ
3737 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
3738 cpu_isset(cpu
, nohz
.cpu_mask
))
3741 if (time_after_eq(jiffies
, rq
->next_balance
))
3742 raise_softirq(SCHED_SOFTIRQ
);
3745 #else /* CONFIG_SMP */
3748 * on UP we do not need to balance between CPUs:
3750 static inline void idle_balance(int cpu
, struct rq
*rq
)
3756 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3758 EXPORT_PER_CPU_SYMBOL(kstat
);
3761 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3762 * that have not yet been banked in case the task is currently running.
3764 unsigned long long task_sched_runtime(struct task_struct
*p
)
3766 unsigned long flags
;
3770 rq
= task_rq_lock(p
, &flags
);
3771 ns
= p
->se
.sum_exec_runtime
;
3772 if (task_current(rq
, p
)) {
3773 update_rq_clock(rq
);
3774 delta_exec
= rq
->clock
- p
->se
.exec_start
;
3775 if ((s64
)delta_exec
> 0)
3778 task_rq_unlock(rq
, &flags
);
3784 * Account user cpu time to a process.
3785 * @p: the process that the cpu time gets accounted to
3786 * @cputime: the cpu time spent in user space since the last update
3788 void account_user_time(struct task_struct
*p
, cputime_t cputime
)
3790 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3793 p
->utime
= cputime_add(p
->utime
, cputime
);
3795 /* Add user time to cpustat. */
3796 tmp
= cputime_to_cputime64(cputime
);
3797 if (TASK_NICE(p
) > 0)
3798 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3800 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3804 * Account guest cpu time to a process.
3805 * @p: the process that the cpu time gets accounted to
3806 * @cputime: the cpu time spent in virtual machine since the last update
3808 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
)
3811 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3813 tmp
= cputime_to_cputime64(cputime
);
3815 p
->utime
= cputime_add(p
->utime
, cputime
);
3816 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3818 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3819 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3823 * Account scaled user cpu time to a process.
3824 * @p: the process that the cpu time gets accounted to
3825 * @cputime: the cpu time spent in user space since the last update
3827 void account_user_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3829 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime
);
3833 * Account system cpu time to a process.
3834 * @p: the process that the cpu time gets accounted to
3835 * @hardirq_offset: the offset to subtract from hardirq_count()
3836 * @cputime: the cpu time spent in kernel space since the last update
3838 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3841 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3842 struct rq
*rq
= this_rq();
3845 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0))
3846 return account_guest_time(p
, cputime
);
3848 p
->stime
= cputime_add(p
->stime
, cputime
);
3850 /* Add system time to cpustat. */
3851 tmp
= cputime_to_cputime64(cputime
);
3852 if (hardirq_count() - hardirq_offset
)
3853 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3854 else if (softirq_count())
3855 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3856 else if (p
!= rq
->idle
)
3857 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3858 else if (atomic_read(&rq
->nr_iowait
) > 0)
3859 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3861 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3862 /* Account for system time used */
3863 acct_update_integrals(p
);
3867 * Account scaled system cpu time to a process.
3868 * @p: the process that the cpu time gets accounted to
3869 * @hardirq_offset: the offset to subtract from hardirq_count()
3870 * @cputime: the cpu time spent in kernel space since the last update
3872 void account_system_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3874 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime
);
3878 * Account for involuntary wait time.
3879 * @p: the process from which the cpu time has been stolen
3880 * @steal: the cpu time spent in involuntary wait
3882 void account_steal_time(struct task_struct
*p
, cputime_t steal
)
3884 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3885 cputime64_t tmp
= cputime_to_cputime64(steal
);
3886 struct rq
*rq
= this_rq();
3888 if (p
== rq
->idle
) {
3889 p
->stime
= cputime_add(p
->stime
, steal
);
3890 if (atomic_read(&rq
->nr_iowait
) > 0)
3891 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3893 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3895 cpustat
->steal
= cputime64_add(cpustat
->steal
, tmp
);
3899 * This function gets called by the timer code, with HZ frequency.
3900 * We call it with interrupts disabled.
3902 * It also gets called by the fork code, when changing the parent's
3905 void scheduler_tick(void)
3907 int cpu
= smp_processor_id();
3908 struct rq
*rq
= cpu_rq(cpu
);
3909 struct task_struct
*curr
= rq
->curr
;
3910 u64 next_tick
= rq
->tick_timestamp
+ TICK_NSEC
;
3912 spin_lock(&rq
->lock
);
3913 __update_rq_clock(rq
);
3915 * Let rq->clock advance by at least TICK_NSEC:
3917 if (unlikely(rq
->clock
< next_tick
)) {
3918 rq
->clock
= next_tick
;
3919 rq
->clock_underflows
++;
3921 rq
->tick_timestamp
= rq
->clock
;
3922 update_last_tick_seen(rq
);
3923 update_cpu_load(rq
);
3924 curr
->sched_class
->task_tick(rq
, curr
, 0);
3925 spin_unlock(&rq
->lock
);
3928 rq
->idle_at_tick
= idle_cpu(cpu
);
3929 trigger_load_balance(rq
, cpu
);
3933 #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
3935 void __kprobes
add_preempt_count(int val
)
3940 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3942 preempt_count() += val
;
3944 * Spinlock count overflowing soon?
3946 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3949 EXPORT_SYMBOL(add_preempt_count
);
3951 void __kprobes
sub_preempt_count(int val
)
3956 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3959 * Is the spinlock portion underflowing?
3961 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3962 !(preempt_count() & PREEMPT_MASK
)))
3965 preempt_count() -= val
;
3967 EXPORT_SYMBOL(sub_preempt_count
);
3972 * Print scheduling while atomic bug:
3974 static noinline
void __schedule_bug(struct task_struct
*prev
)
3976 struct pt_regs
*regs
= get_irq_regs();
3978 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3979 prev
->comm
, prev
->pid
, preempt_count());
3981 debug_show_held_locks(prev
);
3982 if (irqs_disabled())
3983 print_irqtrace_events(prev
);
3992 * Various schedule()-time debugging checks and statistics:
3994 static inline void schedule_debug(struct task_struct
*prev
)
3997 * Test if we are atomic. Since do_exit() needs to call into
3998 * schedule() atomically, we ignore that path for now.
3999 * Otherwise, whine if we are scheduling when we should not be.
4001 if (unlikely(in_atomic_preempt_off()) && unlikely(!prev
->exit_state
))
4002 __schedule_bug(prev
);
4004 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4006 schedstat_inc(this_rq(), sched_count
);
4007 #ifdef CONFIG_SCHEDSTATS
4008 if (unlikely(prev
->lock_depth
>= 0)) {
4009 schedstat_inc(this_rq(), bkl_count
);
4010 schedstat_inc(prev
, sched_info
.bkl_count
);
4016 * Pick up the highest-prio task:
4018 static inline struct task_struct
*
4019 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4021 const struct sched_class
*class;
4022 struct task_struct
*p
;
4025 * Optimization: we know that if all tasks are in
4026 * the fair class we can call that function directly:
4028 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4029 p
= fair_sched_class
.pick_next_task(rq
);
4034 class = sched_class_highest
;
4036 p
= class->pick_next_task(rq
);
4040 * Will never be NULL as the idle class always
4041 * returns a non-NULL p:
4043 class = class->next
;
4048 * schedule() is the main scheduler function.
4050 asmlinkage
void __sched
schedule(void)
4052 struct task_struct
*prev
, *next
;
4053 unsigned long *switch_count
;
4059 cpu
= smp_processor_id();
4063 switch_count
= &prev
->nivcsw
;
4065 release_kernel_lock(prev
);
4066 need_resched_nonpreemptible
:
4068 schedule_debug(prev
);
4073 * Do the rq-clock update outside the rq lock:
4075 local_irq_disable();
4076 __update_rq_clock(rq
);
4077 spin_lock(&rq
->lock
);
4078 clear_tsk_need_resched(prev
);
4080 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4081 if (unlikely((prev
->state
& TASK_INTERRUPTIBLE
) &&
4082 signal_pending(prev
))) {
4083 prev
->state
= TASK_RUNNING
;
4085 deactivate_task(rq
, prev
, 1);
4087 switch_count
= &prev
->nvcsw
;
4091 if (prev
->sched_class
->pre_schedule
)
4092 prev
->sched_class
->pre_schedule(rq
, prev
);
4095 if (unlikely(!rq
->nr_running
))
4096 idle_balance(cpu
, rq
);
4098 prev
->sched_class
->put_prev_task(rq
, prev
);
4099 next
= pick_next_task(rq
, prev
);
4101 sched_info_switch(prev
, next
);
4103 if (likely(prev
!= next
)) {
4108 context_switch(rq
, prev
, next
); /* unlocks the rq */
4110 * the context switch might have flipped the stack from under
4111 * us, hence refresh the local variables.
4113 cpu
= smp_processor_id();
4116 spin_unlock_irq(&rq
->lock
);
4120 if (unlikely(reacquire_kernel_lock(current
) < 0))
4121 goto need_resched_nonpreemptible
;
4123 preempt_enable_no_resched();
4124 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4127 EXPORT_SYMBOL(schedule
);
4129 #ifdef CONFIG_PREEMPT
4131 * this is the entry point to schedule() from in-kernel preemption
4132 * off of preempt_enable. Kernel preemptions off return from interrupt
4133 * occur there and call schedule directly.
4135 asmlinkage
void __sched
preempt_schedule(void)
4137 struct thread_info
*ti
= current_thread_info();
4138 struct task_struct
*task
= current
;
4139 int saved_lock_depth
;
4142 * If there is a non-zero preempt_count or interrupts are disabled,
4143 * we do not want to preempt the current task. Just return..
4145 if (likely(ti
->preempt_count
|| irqs_disabled()))
4149 add_preempt_count(PREEMPT_ACTIVE
);
4152 * We keep the big kernel semaphore locked, but we
4153 * clear ->lock_depth so that schedule() doesnt
4154 * auto-release the semaphore:
4156 saved_lock_depth
= task
->lock_depth
;
4157 task
->lock_depth
= -1;
4159 task
->lock_depth
= saved_lock_depth
;
4160 sub_preempt_count(PREEMPT_ACTIVE
);
4163 * Check again in case we missed a preemption opportunity
4164 * between schedule and now.
4167 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4169 EXPORT_SYMBOL(preempt_schedule
);
4172 * this is the entry point to schedule() from kernel preemption
4173 * off of irq context.
4174 * Note, that this is called and return with irqs disabled. This will
4175 * protect us against recursive calling from irq.
4177 asmlinkage
void __sched
preempt_schedule_irq(void)
4179 struct thread_info
*ti
= current_thread_info();
4180 struct task_struct
*task
= current
;
4181 int saved_lock_depth
;
4183 /* Catch callers which need to be fixed */
4184 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4187 add_preempt_count(PREEMPT_ACTIVE
);
4190 * We keep the big kernel semaphore locked, but we
4191 * clear ->lock_depth so that schedule() doesnt
4192 * auto-release the semaphore:
4194 saved_lock_depth
= task
->lock_depth
;
4195 task
->lock_depth
= -1;
4198 local_irq_disable();
4199 task
->lock_depth
= saved_lock_depth
;
4200 sub_preempt_count(PREEMPT_ACTIVE
);
4203 * Check again in case we missed a preemption opportunity
4204 * between schedule and now.
4207 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4210 #endif /* CONFIG_PREEMPT */
4212 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4215 return try_to_wake_up(curr
->private, mode
, sync
);
4217 EXPORT_SYMBOL(default_wake_function
);
4220 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4221 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4222 * number) then we wake all the non-exclusive tasks and one exclusive task.
4224 * There are circumstances in which we can try to wake a task which has already
4225 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4226 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4228 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4229 int nr_exclusive
, int sync
, void *key
)
4231 wait_queue_t
*curr
, *next
;
4233 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4234 unsigned flags
= curr
->flags
;
4236 if (curr
->func(curr
, mode
, sync
, key
) &&
4237 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4243 * __wake_up - wake up threads blocked on a waitqueue.
4245 * @mode: which threads
4246 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4247 * @key: is directly passed to the wakeup function
4249 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4250 int nr_exclusive
, void *key
)
4252 unsigned long flags
;
4254 spin_lock_irqsave(&q
->lock
, flags
);
4255 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4256 spin_unlock_irqrestore(&q
->lock
, flags
);
4258 EXPORT_SYMBOL(__wake_up
);
4261 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4263 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4265 __wake_up_common(q
, mode
, 1, 0, NULL
);
4269 * __wake_up_sync - wake up threads blocked on a waitqueue.
4271 * @mode: which threads
4272 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4274 * The sync wakeup differs that the waker knows that it will schedule
4275 * away soon, so while the target thread will be woken up, it will not
4276 * be migrated to another CPU - ie. the two threads are 'synchronized'
4277 * with each other. This can prevent needless bouncing between CPUs.
4279 * On UP it can prevent extra preemption.
4282 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4284 unsigned long flags
;
4290 if (unlikely(!nr_exclusive
))
4293 spin_lock_irqsave(&q
->lock
, flags
);
4294 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4295 spin_unlock_irqrestore(&q
->lock
, flags
);
4297 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4299 void complete(struct completion
*x
)
4301 unsigned long flags
;
4303 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4305 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4306 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4308 EXPORT_SYMBOL(complete
);
4310 void complete_all(struct completion
*x
)
4312 unsigned long flags
;
4314 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4315 x
->done
+= UINT_MAX
/2;
4316 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4317 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4319 EXPORT_SYMBOL(complete_all
);
4321 static inline long __sched
4322 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4325 DECLARE_WAITQUEUE(wait
, current
);
4327 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4328 __add_wait_queue_tail(&x
->wait
, &wait
);
4330 if ((state
== TASK_INTERRUPTIBLE
&&
4331 signal_pending(current
)) ||
4332 (state
== TASK_KILLABLE
&&
4333 fatal_signal_pending(current
))) {
4334 __remove_wait_queue(&x
->wait
, &wait
);
4335 return -ERESTARTSYS
;
4337 __set_current_state(state
);
4338 spin_unlock_irq(&x
->wait
.lock
);
4339 timeout
= schedule_timeout(timeout
);
4340 spin_lock_irq(&x
->wait
.lock
);
4342 __remove_wait_queue(&x
->wait
, &wait
);
4346 __remove_wait_queue(&x
->wait
, &wait
);
4353 wait_for_common(struct completion
*x
, long timeout
, int state
)
4357 spin_lock_irq(&x
->wait
.lock
);
4358 timeout
= do_wait_for_common(x
, timeout
, state
);
4359 spin_unlock_irq(&x
->wait
.lock
);
4363 void __sched
wait_for_completion(struct completion
*x
)
4365 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4367 EXPORT_SYMBOL(wait_for_completion
);
4369 unsigned long __sched
4370 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4372 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4374 EXPORT_SYMBOL(wait_for_completion_timeout
);
4376 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4378 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4379 if (t
== -ERESTARTSYS
)
4383 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4385 unsigned long __sched
4386 wait_for_completion_interruptible_timeout(struct completion
*x
,
4387 unsigned long timeout
)
4389 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4391 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4393 int __sched
wait_for_completion_killable(struct completion
*x
)
4395 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4396 if (t
== -ERESTARTSYS
)
4400 EXPORT_SYMBOL(wait_for_completion_killable
);
4403 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4405 unsigned long flags
;
4408 init_waitqueue_entry(&wait
, current
);
4410 __set_current_state(state
);
4412 spin_lock_irqsave(&q
->lock
, flags
);
4413 __add_wait_queue(q
, &wait
);
4414 spin_unlock(&q
->lock
);
4415 timeout
= schedule_timeout(timeout
);
4416 spin_lock_irq(&q
->lock
);
4417 __remove_wait_queue(q
, &wait
);
4418 spin_unlock_irqrestore(&q
->lock
, flags
);
4423 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4425 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4427 EXPORT_SYMBOL(interruptible_sleep_on
);
4430 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4432 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4434 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4436 void __sched
sleep_on(wait_queue_head_t
*q
)
4438 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4440 EXPORT_SYMBOL(sleep_on
);
4442 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4444 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4446 EXPORT_SYMBOL(sleep_on_timeout
);
4448 #ifdef CONFIG_RT_MUTEXES
4451 * rt_mutex_setprio - set the current priority of a task
4453 * @prio: prio value (kernel-internal form)
4455 * This function changes the 'effective' priority of a task. It does
4456 * not touch ->normal_prio like __setscheduler().
4458 * Used by the rt_mutex code to implement priority inheritance logic.
4460 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4462 unsigned long flags
;
4463 int oldprio
, on_rq
, running
;
4465 const struct sched_class
*prev_class
= p
->sched_class
;
4467 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4469 rq
= task_rq_lock(p
, &flags
);
4470 update_rq_clock(rq
);
4473 on_rq
= p
->se
.on_rq
;
4474 running
= task_current(rq
, p
);
4476 dequeue_task(rq
, p
, 0);
4478 p
->sched_class
->put_prev_task(rq
, p
);
4481 p
->sched_class
= &rt_sched_class
;
4483 p
->sched_class
= &fair_sched_class
;
4488 p
->sched_class
->set_curr_task(rq
);
4490 enqueue_task(rq
, p
, 0);
4492 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4494 task_rq_unlock(rq
, &flags
);
4499 void set_user_nice(struct task_struct
*p
, long nice
)
4501 int old_prio
, delta
, on_rq
;
4502 unsigned long flags
;
4505 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4508 * We have to be careful, if called from sys_setpriority(),
4509 * the task might be in the middle of scheduling on another CPU.
4511 rq
= task_rq_lock(p
, &flags
);
4512 update_rq_clock(rq
);
4514 * The RT priorities are set via sched_setscheduler(), but we still
4515 * allow the 'normal' nice value to be set - but as expected
4516 * it wont have any effect on scheduling until the task is
4517 * SCHED_FIFO/SCHED_RR:
4519 if (task_has_rt_policy(p
)) {
4520 p
->static_prio
= NICE_TO_PRIO(nice
);
4523 on_rq
= p
->se
.on_rq
;
4525 dequeue_task(rq
, p
, 0);
4529 p
->static_prio
= NICE_TO_PRIO(nice
);
4532 p
->prio
= effective_prio(p
);
4533 delta
= p
->prio
- old_prio
;
4536 enqueue_task(rq
, p
, 0);
4539 * If the task increased its priority or is running and
4540 * lowered its priority, then reschedule its CPU:
4542 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4543 resched_task(rq
->curr
);
4546 task_rq_unlock(rq
, &flags
);
4548 EXPORT_SYMBOL(set_user_nice
);
4551 * can_nice - check if a task can reduce its nice value
4555 int can_nice(const struct task_struct
*p
, const int nice
)
4557 /* convert nice value [19,-20] to rlimit style value [1,40] */
4558 int nice_rlim
= 20 - nice
;
4560 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
4561 capable(CAP_SYS_NICE
));
4564 #ifdef __ARCH_WANT_SYS_NICE
4567 * sys_nice - change the priority of the current process.
4568 * @increment: priority increment
4570 * sys_setpriority is a more generic, but much slower function that
4571 * does similar things.
4573 asmlinkage
long sys_nice(int increment
)
4578 * Setpriority might change our priority at the same moment.
4579 * We don't have to worry. Conceptually one call occurs first
4580 * and we have a single winner.
4582 if (increment
< -40)
4587 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
4593 if (increment
< 0 && !can_nice(current
, nice
))
4596 retval
= security_task_setnice(current
, nice
);
4600 set_user_nice(current
, nice
);
4607 * task_prio - return the priority value of a given task.
4608 * @p: the task in question.
4610 * This is the priority value as seen by users in /proc.
4611 * RT tasks are offset by -200. Normal tasks are centered
4612 * around 0, value goes from -16 to +15.
4614 int task_prio(const struct task_struct
*p
)
4616 return p
->prio
- MAX_RT_PRIO
;
4620 * task_nice - return the nice value of a given task.
4621 * @p: the task in question.
4623 int task_nice(const struct task_struct
*p
)
4625 return TASK_NICE(p
);
4627 EXPORT_SYMBOL(task_nice
);
4630 * idle_cpu - is a given cpu idle currently?
4631 * @cpu: the processor in question.
4633 int idle_cpu(int cpu
)
4635 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4639 * idle_task - return the idle task for a given cpu.
4640 * @cpu: the processor in question.
4642 struct task_struct
*idle_task(int cpu
)
4644 return cpu_rq(cpu
)->idle
;
4648 * find_process_by_pid - find a process with a matching PID value.
4649 * @pid: the pid in question.
4651 static struct task_struct
*find_process_by_pid(pid_t pid
)
4653 return pid
? find_task_by_vpid(pid
) : current
;
4656 /* Actually do priority change: must hold rq lock. */
4658 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4660 BUG_ON(p
->se
.on_rq
);
4663 switch (p
->policy
) {
4667 p
->sched_class
= &fair_sched_class
;
4671 p
->sched_class
= &rt_sched_class
;
4675 p
->rt_priority
= prio
;
4676 p
->normal_prio
= normal_prio(p
);
4677 /* we are holding p->pi_lock already */
4678 p
->prio
= rt_mutex_getprio(p
);
4683 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4684 * @p: the task in question.
4685 * @policy: new policy.
4686 * @param: structure containing the new RT priority.
4688 * NOTE that the task may be already dead.
4690 int sched_setscheduler(struct task_struct
*p
, int policy
,
4691 struct sched_param
*param
)
4693 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4694 unsigned long flags
;
4695 const struct sched_class
*prev_class
= p
->sched_class
;
4698 /* may grab non-irq protected spin_locks */
4699 BUG_ON(in_interrupt());
4701 /* double check policy once rq lock held */
4703 policy
= oldpolicy
= p
->policy
;
4704 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4705 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4706 policy
!= SCHED_IDLE
)
4709 * Valid priorities for SCHED_FIFO and SCHED_RR are
4710 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4711 * SCHED_BATCH and SCHED_IDLE is 0.
4713 if (param
->sched_priority
< 0 ||
4714 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4715 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4717 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4721 * Allow unprivileged RT tasks to decrease priority:
4723 if (!capable(CAP_SYS_NICE
)) {
4724 if (rt_policy(policy
)) {
4725 unsigned long rlim_rtprio
;
4727 if (!lock_task_sighand(p
, &flags
))
4729 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
4730 unlock_task_sighand(p
, &flags
);
4732 /* can't set/change the rt policy */
4733 if (policy
!= p
->policy
&& !rlim_rtprio
)
4736 /* can't increase priority */
4737 if (param
->sched_priority
> p
->rt_priority
&&
4738 param
->sched_priority
> rlim_rtprio
)
4742 * Like positive nice levels, dont allow tasks to
4743 * move out of SCHED_IDLE either:
4745 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4748 /* can't change other user's priorities */
4749 if ((current
->euid
!= p
->euid
) &&
4750 (current
->euid
!= p
->uid
))
4754 #ifdef CONFIG_RT_GROUP_SCHED
4756 * Do not allow realtime tasks into groups that have no runtime
4759 if (rt_policy(policy
) && task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
4763 retval
= security_task_setscheduler(p
, policy
, param
);
4767 * make sure no PI-waiters arrive (or leave) while we are
4768 * changing the priority of the task:
4770 spin_lock_irqsave(&p
->pi_lock
, flags
);
4772 * To be able to change p->policy safely, the apropriate
4773 * runqueue lock must be held.
4775 rq
= __task_rq_lock(p
);
4776 /* recheck policy now with rq lock held */
4777 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4778 policy
= oldpolicy
= -1;
4779 __task_rq_unlock(rq
);
4780 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4783 update_rq_clock(rq
);
4784 on_rq
= p
->se
.on_rq
;
4785 running
= task_current(rq
, p
);
4787 deactivate_task(rq
, p
, 0);
4789 p
->sched_class
->put_prev_task(rq
, p
);
4792 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4795 p
->sched_class
->set_curr_task(rq
);
4797 activate_task(rq
, p
, 0);
4799 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4801 __task_rq_unlock(rq
);
4802 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4804 rt_mutex_adjust_pi(p
);
4808 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4811 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4813 struct sched_param lparam
;
4814 struct task_struct
*p
;
4817 if (!param
|| pid
< 0)
4819 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4824 p
= find_process_by_pid(pid
);
4826 retval
= sched_setscheduler(p
, policy
, &lparam
);
4833 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4834 * @pid: the pid in question.
4835 * @policy: new policy.
4836 * @param: structure containing the new RT priority.
4839 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4841 /* negative values for policy are not valid */
4845 return do_sched_setscheduler(pid
, policy
, param
);
4849 * sys_sched_setparam - set/change the RT priority of a thread
4850 * @pid: the pid in question.
4851 * @param: structure containing the new RT priority.
4853 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
4855 return do_sched_setscheduler(pid
, -1, param
);
4859 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4860 * @pid: the pid in question.
4862 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
4864 struct task_struct
*p
;
4871 read_lock(&tasklist_lock
);
4872 p
= find_process_by_pid(pid
);
4874 retval
= security_task_getscheduler(p
);
4878 read_unlock(&tasklist_lock
);
4883 * sys_sched_getscheduler - get the RT priority of a thread
4884 * @pid: the pid in question.
4885 * @param: structure containing the RT priority.
4887 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
4889 struct sched_param lp
;
4890 struct task_struct
*p
;
4893 if (!param
|| pid
< 0)
4896 read_lock(&tasklist_lock
);
4897 p
= find_process_by_pid(pid
);
4902 retval
= security_task_getscheduler(p
);
4906 lp
.sched_priority
= p
->rt_priority
;
4907 read_unlock(&tasklist_lock
);
4910 * This one might sleep, we cannot do it with a spinlock held ...
4912 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4917 read_unlock(&tasklist_lock
);
4921 long sched_setaffinity(pid_t pid
, const cpumask_t
*in_mask
)
4923 cpumask_t cpus_allowed
;
4924 cpumask_t new_mask
= *in_mask
;
4925 struct task_struct
*p
;
4929 read_lock(&tasklist_lock
);
4931 p
= find_process_by_pid(pid
);
4933 read_unlock(&tasklist_lock
);
4939 * It is not safe to call set_cpus_allowed with the
4940 * tasklist_lock held. We will bump the task_struct's
4941 * usage count and then drop tasklist_lock.
4944 read_unlock(&tasklist_lock
);
4947 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
4948 !capable(CAP_SYS_NICE
))
4951 retval
= security_task_setscheduler(p
, 0, NULL
);
4955 cpuset_cpus_allowed(p
, &cpus_allowed
);
4956 cpus_and(new_mask
, new_mask
, cpus_allowed
);
4958 retval
= set_cpus_allowed_ptr(p
, &new_mask
);
4961 cpuset_cpus_allowed(p
, &cpus_allowed
);
4962 if (!cpus_subset(new_mask
, cpus_allowed
)) {
4964 * We must have raced with a concurrent cpuset
4965 * update. Just reset the cpus_allowed to the
4966 * cpuset's cpus_allowed
4968 new_mask
= cpus_allowed
;
4978 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4979 cpumask_t
*new_mask
)
4981 if (len
< sizeof(cpumask_t
)) {
4982 memset(new_mask
, 0, sizeof(cpumask_t
));
4983 } else if (len
> sizeof(cpumask_t
)) {
4984 len
= sizeof(cpumask_t
);
4986 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4990 * sys_sched_setaffinity - set the cpu affinity of a process
4991 * @pid: pid of the process
4992 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4993 * @user_mask_ptr: user-space pointer to the new cpu mask
4995 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
4996 unsigned long __user
*user_mask_ptr
)
5001 retval
= get_user_cpu_mask(user_mask_ptr
, len
, &new_mask
);
5005 return sched_setaffinity(pid
, &new_mask
);
5009 * Represents all cpu's present in the system
5010 * In systems capable of hotplug, this map could dynamically grow
5011 * as new cpu's are detected in the system via any platform specific
5012 * method, such as ACPI for e.g.
5015 cpumask_t cpu_present_map __read_mostly
;
5016 EXPORT_SYMBOL(cpu_present_map
);
5019 cpumask_t cpu_online_map __read_mostly
= CPU_MASK_ALL
;
5020 EXPORT_SYMBOL(cpu_online_map
);
5022 cpumask_t cpu_possible_map __read_mostly
= CPU_MASK_ALL
;
5023 EXPORT_SYMBOL(cpu_possible_map
);
5026 long sched_getaffinity(pid_t pid
, cpumask_t
*mask
)
5028 struct task_struct
*p
;
5032 read_lock(&tasklist_lock
);
5035 p
= find_process_by_pid(pid
);
5039 retval
= security_task_getscheduler(p
);
5043 cpus_and(*mask
, p
->cpus_allowed
, cpu_online_map
);
5046 read_unlock(&tasklist_lock
);
5053 * sys_sched_getaffinity - get the cpu affinity of a process
5054 * @pid: pid of the process
5055 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5056 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5058 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5059 unsigned long __user
*user_mask_ptr
)
5064 if (len
< sizeof(cpumask_t
))
5067 ret
= sched_getaffinity(pid
, &mask
);
5071 if (copy_to_user(user_mask_ptr
, &mask
, sizeof(cpumask_t
)))
5074 return sizeof(cpumask_t
);
5078 * sys_sched_yield - yield the current processor to other threads.
5080 * This function yields the current CPU to other tasks. If there are no
5081 * other threads running on this CPU then this function will return.
5083 asmlinkage
long sys_sched_yield(void)
5085 struct rq
*rq
= this_rq_lock();
5087 schedstat_inc(rq
, yld_count
);
5088 current
->sched_class
->yield_task(rq
);
5091 * Since we are going to call schedule() anyway, there's
5092 * no need to preempt or enable interrupts:
5094 __release(rq
->lock
);
5095 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5096 _raw_spin_unlock(&rq
->lock
);
5097 preempt_enable_no_resched();
5104 static void __cond_resched(void)
5106 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5107 __might_sleep(__FILE__
, __LINE__
);
5110 * The BKS might be reacquired before we have dropped
5111 * PREEMPT_ACTIVE, which could trigger a second
5112 * cond_resched() call.
5115 add_preempt_count(PREEMPT_ACTIVE
);
5117 sub_preempt_count(PREEMPT_ACTIVE
);
5118 } while (need_resched());
5121 #if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY)
5122 int __sched
_cond_resched(void)
5124 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5125 system_state
== SYSTEM_RUNNING
) {
5131 EXPORT_SYMBOL(_cond_resched
);
5135 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5136 * call schedule, and on return reacquire the lock.
5138 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5139 * operations here to prevent schedule() from being called twice (once via
5140 * spin_unlock(), once by hand).
5142 int cond_resched_lock(spinlock_t
*lock
)
5144 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5147 if (spin_needbreak(lock
) || resched
) {
5149 if (resched
&& need_resched())
5158 EXPORT_SYMBOL(cond_resched_lock
);
5160 int __sched
cond_resched_softirq(void)
5162 BUG_ON(!in_softirq());
5164 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5172 EXPORT_SYMBOL(cond_resched_softirq
);
5175 * yield - yield the current processor to other threads.
5177 * This is a shortcut for kernel-space yielding - it marks the
5178 * thread runnable and calls sys_sched_yield().
5180 void __sched
yield(void)
5182 set_current_state(TASK_RUNNING
);
5185 EXPORT_SYMBOL(yield
);
5188 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5189 * that process accounting knows that this is a task in IO wait state.
5191 * But don't do that if it is a deliberate, throttling IO wait (this task
5192 * has set its backing_dev_info: the queue against which it should throttle)
5194 void __sched
io_schedule(void)
5196 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5198 delayacct_blkio_start();
5199 atomic_inc(&rq
->nr_iowait
);
5201 atomic_dec(&rq
->nr_iowait
);
5202 delayacct_blkio_end();
5204 EXPORT_SYMBOL(io_schedule
);
5206 long __sched
io_schedule_timeout(long timeout
)
5208 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5211 delayacct_blkio_start();
5212 atomic_inc(&rq
->nr_iowait
);
5213 ret
= schedule_timeout(timeout
);
5214 atomic_dec(&rq
->nr_iowait
);
5215 delayacct_blkio_end();
5220 * sys_sched_get_priority_max - return maximum RT priority.
5221 * @policy: scheduling class.
5223 * this syscall returns the maximum rt_priority that can be used
5224 * by a given scheduling class.
5226 asmlinkage
long sys_sched_get_priority_max(int policy
)
5233 ret
= MAX_USER_RT_PRIO
-1;
5245 * sys_sched_get_priority_min - return minimum RT priority.
5246 * @policy: scheduling class.
5248 * this syscall returns the minimum rt_priority that can be used
5249 * by a given scheduling class.
5251 asmlinkage
long sys_sched_get_priority_min(int policy
)
5269 * sys_sched_rr_get_interval - return the default timeslice of a process.
5270 * @pid: pid of the process.
5271 * @interval: userspace pointer to the timeslice value.
5273 * this syscall writes the default timeslice value of a given process
5274 * into the user-space timespec buffer. A value of '0' means infinity.
5277 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5279 struct task_struct
*p
;
5280 unsigned int time_slice
;
5288 read_lock(&tasklist_lock
);
5289 p
= find_process_by_pid(pid
);
5293 retval
= security_task_getscheduler(p
);
5298 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5299 * tasks that are on an otherwise idle runqueue:
5302 if (p
->policy
== SCHED_RR
) {
5303 time_slice
= DEF_TIMESLICE
;
5304 } else if (p
->policy
!= SCHED_FIFO
) {
5305 struct sched_entity
*se
= &p
->se
;
5306 unsigned long flags
;
5309 rq
= task_rq_lock(p
, &flags
);
5310 if (rq
->cfs
.load
.weight
)
5311 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5312 task_rq_unlock(rq
, &flags
);
5314 read_unlock(&tasklist_lock
);
5315 jiffies_to_timespec(time_slice
, &t
);
5316 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5320 read_unlock(&tasklist_lock
);
5324 static const char stat_nam
[] = "RSDTtZX";
5326 void sched_show_task(struct task_struct
*p
)
5328 unsigned long free
= 0;
5331 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5332 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5333 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5334 #if BITS_PER_LONG == 32
5335 if (state
== TASK_RUNNING
)
5336 printk(KERN_CONT
" running ");
5338 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5340 if (state
== TASK_RUNNING
)
5341 printk(KERN_CONT
" running task ");
5343 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5345 #ifdef CONFIG_DEBUG_STACK_USAGE
5347 unsigned long *n
= end_of_stack(p
);
5350 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
5353 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
5354 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
5356 show_stack(p
, NULL
);
5359 void show_state_filter(unsigned long state_filter
)
5361 struct task_struct
*g
, *p
;
5363 #if BITS_PER_LONG == 32
5365 " task PC stack pid father\n");
5368 " task PC stack pid father\n");
5370 read_lock(&tasklist_lock
);
5371 do_each_thread(g
, p
) {
5373 * reset the NMI-timeout, listing all files on a slow
5374 * console might take alot of time:
5376 touch_nmi_watchdog();
5377 if (!state_filter
|| (p
->state
& state_filter
))
5379 } while_each_thread(g
, p
);
5381 touch_all_softlockup_watchdogs();
5383 #ifdef CONFIG_SCHED_DEBUG
5384 sysrq_sched_debug_show();
5386 read_unlock(&tasklist_lock
);
5388 * Only show locks if all tasks are dumped:
5390 if (state_filter
== -1)
5391 debug_show_all_locks();
5394 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5396 idle
->sched_class
= &idle_sched_class
;
5400 * init_idle - set up an idle thread for a given CPU
5401 * @idle: task in question
5402 * @cpu: cpu the idle task belongs to
5404 * NOTE: this function does not set the idle thread's NEED_RESCHED
5405 * flag, to make booting more robust.
5407 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5409 struct rq
*rq
= cpu_rq(cpu
);
5410 unsigned long flags
;
5413 idle
->se
.exec_start
= sched_clock();
5415 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
5416 idle
->cpus_allowed
= cpumask_of_cpu(cpu
);
5417 __set_task_cpu(idle
, cpu
);
5419 spin_lock_irqsave(&rq
->lock
, flags
);
5420 rq
->curr
= rq
->idle
= idle
;
5421 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5424 spin_unlock_irqrestore(&rq
->lock
, flags
);
5426 /* Set the preempt count _outside_ the spinlocks! */
5427 task_thread_info(idle
)->preempt_count
= 0;
5430 * The idle tasks have their own, simple scheduling class:
5432 idle
->sched_class
= &idle_sched_class
;
5436 * In a system that switches off the HZ timer nohz_cpu_mask
5437 * indicates which cpus entered this state. This is used
5438 * in the rcu update to wait only for active cpus. For system
5439 * which do not switch off the HZ timer nohz_cpu_mask should
5440 * always be CPU_MASK_NONE.
5442 cpumask_t nohz_cpu_mask
= CPU_MASK_NONE
;
5445 * Increase the granularity value when there are more CPUs,
5446 * because with more CPUs the 'effective latency' as visible
5447 * to users decreases. But the relationship is not linear,
5448 * so pick a second-best guess by going with the log2 of the
5451 * This idea comes from the SD scheduler of Con Kolivas:
5453 static inline void sched_init_granularity(void)
5455 unsigned int factor
= 1 + ilog2(num_online_cpus());
5456 const unsigned long limit
= 200000000;
5458 sysctl_sched_min_granularity
*= factor
;
5459 if (sysctl_sched_min_granularity
> limit
)
5460 sysctl_sched_min_granularity
= limit
;
5462 sysctl_sched_latency
*= factor
;
5463 if (sysctl_sched_latency
> limit
)
5464 sysctl_sched_latency
= limit
;
5466 sysctl_sched_wakeup_granularity
*= factor
;
5471 * This is how migration works:
5473 * 1) we queue a struct migration_req structure in the source CPU's
5474 * runqueue and wake up that CPU's migration thread.
5475 * 2) we down() the locked semaphore => thread blocks.
5476 * 3) migration thread wakes up (implicitly it forces the migrated
5477 * thread off the CPU)
5478 * 4) it gets the migration request and checks whether the migrated
5479 * task is still in the wrong runqueue.
5480 * 5) if it's in the wrong runqueue then the migration thread removes
5481 * it and puts it into the right queue.
5482 * 6) migration thread up()s the semaphore.
5483 * 7) we wake up and the migration is done.
5487 * Change a given task's CPU affinity. Migrate the thread to a
5488 * proper CPU and schedule it away if the CPU it's executing on
5489 * is removed from the allowed bitmask.
5491 * NOTE: the caller must have a valid reference to the task, the
5492 * task must not exit() & deallocate itself prematurely. The
5493 * call is not atomic; no spinlocks may be held.
5495 int set_cpus_allowed_ptr(struct task_struct
*p
, const cpumask_t
*new_mask
)
5497 struct migration_req req
;
5498 unsigned long flags
;
5502 rq
= task_rq_lock(p
, &flags
);
5503 if (!cpus_intersects(*new_mask
, cpu_online_map
)) {
5508 if (p
->sched_class
->set_cpus_allowed
)
5509 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5511 p
->cpus_allowed
= *new_mask
;
5512 p
->rt
.nr_cpus_allowed
= cpus_weight(*new_mask
);
5515 /* Can the task run on the task's current CPU? If so, we're done */
5516 if (cpu_isset(task_cpu(p
), *new_mask
))
5519 if (migrate_task(p
, any_online_cpu(*new_mask
), &req
)) {
5520 /* Need help from migration thread: drop lock and wait. */
5521 task_rq_unlock(rq
, &flags
);
5522 wake_up_process(rq
->migration_thread
);
5523 wait_for_completion(&req
.done
);
5524 tlb_migrate_finish(p
->mm
);
5528 task_rq_unlock(rq
, &flags
);
5532 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5535 * Move (not current) task off this cpu, onto dest cpu. We're doing
5536 * this because either it can't run here any more (set_cpus_allowed()
5537 * away from this CPU, or CPU going down), or because we're
5538 * attempting to rebalance this task on exec (sched_exec).
5540 * So we race with normal scheduler movements, but that's OK, as long
5541 * as the task is no longer on this CPU.
5543 * Returns non-zero if task was successfully migrated.
5545 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5547 struct rq
*rq_dest
, *rq_src
;
5550 if (unlikely(cpu_is_offline(dest_cpu
)))
5553 rq_src
= cpu_rq(src_cpu
);
5554 rq_dest
= cpu_rq(dest_cpu
);
5556 double_rq_lock(rq_src
, rq_dest
);
5557 /* Already moved. */
5558 if (task_cpu(p
) != src_cpu
)
5560 /* Affinity changed (again). */
5561 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
))
5564 on_rq
= p
->se
.on_rq
;
5566 deactivate_task(rq_src
, p
, 0);
5568 set_task_cpu(p
, dest_cpu
);
5570 activate_task(rq_dest
, p
, 0);
5571 check_preempt_curr(rq_dest
, p
);
5575 double_rq_unlock(rq_src
, rq_dest
);
5580 * migration_thread - this is a highprio system thread that performs
5581 * thread migration by bumping thread off CPU then 'pushing' onto
5584 static int migration_thread(void *data
)
5586 int cpu
= (long)data
;
5590 BUG_ON(rq
->migration_thread
!= current
);
5592 set_current_state(TASK_INTERRUPTIBLE
);
5593 while (!kthread_should_stop()) {
5594 struct migration_req
*req
;
5595 struct list_head
*head
;
5597 spin_lock_irq(&rq
->lock
);
5599 if (cpu_is_offline(cpu
)) {
5600 spin_unlock_irq(&rq
->lock
);
5604 if (rq
->active_balance
) {
5605 active_load_balance(rq
, cpu
);
5606 rq
->active_balance
= 0;
5609 head
= &rq
->migration_queue
;
5611 if (list_empty(head
)) {
5612 spin_unlock_irq(&rq
->lock
);
5614 set_current_state(TASK_INTERRUPTIBLE
);
5617 req
= list_entry(head
->next
, struct migration_req
, list
);
5618 list_del_init(head
->next
);
5620 spin_unlock(&rq
->lock
);
5621 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
5624 complete(&req
->done
);
5626 __set_current_state(TASK_RUNNING
);
5630 /* Wait for kthread_stop */
5631 set_current_state(TASK_INTERRUPTIBLE
);
5632 while (!kthread_should_stop()) {
5634 set_current_state(TASK_INTERRUPTIBLE
);
5636 __set_current_state(TASK_RUNNING
);
5640 #ifdef CONFIG_HOTPLUG_CPU
5642 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5646 local_irq_disable();
5647 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
5653 * Figure out where task on dead CPU should go, use force if necessary.
5654 * NOTE: interrupts should be disabled by the caller
5656 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5658 unsigned long flags
;
5665 mask
= node_to_cpumask(cpu_to_node(dead_cpu
));
5666 cpus_and(mask
, mask
, p
->cpus_allowed
);
5667 dest_cpu
= any_online_cpu(mask
);
5669 /* On any allowed CPU? */
5670 if (dest_cpu
>= nr_cpu_ids
)
5671 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5673 /* No more Mr. Nice Guy. */
5674 if (dest_cpu
>= nr_cpu_ids
) {
5675 cpumask_t cpus_allowed
;
5677 cpuset_cpus_allowed_locked(p
, &cpus_allowed
);
5679 * Try to stay on the same cpuset, where the
5680 * current cpuset may be a subset of all cpus.
5681 * The cpuset_cpus_allowed_locked() variant of
5682 * cpuset_cpus_allowed() will not block. It must be
5683 * called within calls to cpuset_lock/cpuset_unlock.
5685 rq
= task_rq_lock(p
, &flags
);
5686 p
->cpus_allowed
= cpus_allowed
;
5687 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5688 task_rq_unlock(rq
, &flags
);
5691 * Don't tell them about moving exiting tasks or
5692 * kernel threads (both mm NULL), since they never
5695 if (p
->mm
&& printk_ratelimit()) {
5696 printk(KERN_INFO
"process %d (%s) no "
5697 "longer affine to cpu%d\n",
5698 task_pid_nr(p
), p
->comm
, dead_cpu
);
5701 } while (!__migrate_task_irq(p
, dead_cpu
, dest_cpu
));
5705 * While a dead CPU has no uninterruptible tasks queued at this point,
5706 * it might still have a nonzero ->nr_uninterruptible counter, because
5707 * for performance reasons the counter is not stricly tracking tasks to
5708 * their home CPUs. So we just add the counter to another CPU's counter,
5709 * to keep the global sum constant after CPU-down:
5711 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5713 struct rq
*rq_dest
= cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR
));
5714 unsigned long flags
;
5716 local_irq_save(flags
);
5717 double_rq_lock(rq_src
, rq_dest
);
5718 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5719 rq_src
->nr_uninterruptible
= 0;
5720 double_rq_unlock(rq_src
, rq_dest
);
5721 local_irq_restore(flags
);
5724 /* Run through task list and migrate tasks from the dead cpu. */
5725 static void migrate_live_tasks(int src_cpu
)
5727 struct task_struct
*p
, *t
;
5729 read_lock(&tasklist_lock
);
5731 do_each_thread(t
, p
) {
5735 if (task_cpu(p
) == src_cpu
)
5736 move_task_off_dead_cpu(src_cpu
, p
);
5737 } while_each_thread(t
, p
);
5739 read_unlock(&tasklist_lock
);
5743 * Schedules idle task to be the next runnable task on current CPU.
5744 * It does so by boosting its priority to highest possible.
5745 * Used by CPU offline code.
5747 void sched_idle_next(void)
5749 int this_cpu
= smp_processor_id();
5750 struct rq
*rq
= cpu_rq(this_cpu
);
5751 struct task_struct
*p
= rq
->idle
;
5752 unsigned long flags
;
5754 /* cpu has to be offline */
5755 BUG_ON(cpu_online(this_cpu
));
5758 * Strictly not necessary since rest of the CPUs are stopped by now
5759 * and interrupts disabled on the current cpu.
5761 spin_lock_irqsave(&rq
->lock
, flags
);
5763 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5765 update_rq_clock(rq
);
5766 activate_task(rq
, p
, 0);
5768 spin_unlock_irqrestore(&rq
->lock
, flags
);
5772 * Ensures that the idle task is using init_mm right before its cpu goes
5775 void idle_task_exit(void)
5777 struct mm_struct
*mm
= current
->active_mm
;
5779 BUG_ON(cpu_online(smp_processor_id()));
5782 switch_mm(mm
, &init_mm
, current
);
5786 /* called under rq->lock with disabled interrupts */
5787 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5789 struct rq
*rq
= cpu_rq(dead_cpu
);
5791 /* Must be exiting, otherwise would be on tasklist. */
5792 BUG_ON(!p
->exit_state
);
5794 /* Cannot have done final schedule yet: would have vanished. */
5795 BUG_ON(p
->state
== TASK_DEAD
);
5800 * Drop lock around migration; if someone else moves it,
5801 * that's OK. No task can be added to this CPU, so iteration is
5804 spin_unlock_irq(&rq
->lock
);
5805 move_task_off_dead_cpu(dead_cpu
, p
);
5806 spin_lock_irq(&rq
->lock
);
5811 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5812 static void migrate_dead_tasks(unsigned int dead_cpu
)
5814 struct rq
*rq
= cpu_rq(dead_cpu
);
5815 struct task_struct
*next
;
5818 if (!rq
->nr_running
)
5820 update_rq_clock(rq
);
5821 next
= pick_next_task(rq
, rq
->curr
);
5824 migrate_dead(dead_cpu
, next
);
5828 #endif /* CONFIG_HOTPLUG_CPU */
5830 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5832 static struct ctl_table sd_ctl_dir
[] = {
5834 .procname
= "sched_domain",
5840 static struct ctl_table sd_ctl_root
[] = {
5842 .ctl_name
= CTL_KERN
,
5843 .procname
= "kernel",
5845 .child
= sd_ctl_dir
,
5850 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5852 struct ctl_table
*entry
=
5853 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5858 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5860 struct ctl_table
*entry
;
5863 * In the intermediate directories, both the child directory and
5864 * procname are dynamically allocated and could fail but the mode
5865 * will always be set. In the lowest directory the names are
5866 * static strings and all have proc handlers.
5868 for (entry
= *tablep
; entry
->mode
; entry
++) {
5870 sd_free_ctl_entry(&entry
->child
);
5871 if (entry
->proc_handler
== NULL
)
5872 kfree(entry
->procname
);
5880 set_table_entry(struct ctl_table
*entry
,
5881 const char *procname
, void *data
, int maxlen
,
5882 mode_t mode
, proc_handler
*proc_handler
)
5884 entry
->procname
= procname
;
5886 entry
->maxlen
= maxlen
;
5888 entry
->proc_handler
= proc_handler
;
5891 static struct ctl_table
*
5892 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5894 struct ctl_table
*table
= sd_alloc_ctl_entry(12);
5899 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5900 sizeof(long), 0644, proc_doulongvec_minmax
);
5901 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5902 sizeof(long), 0644, proc_doulongvec_minmax
);
5903 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5904 sizeof(int), 0644, proc_dointvec_minmax
);
5905 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5906 sizeof(int), 0644, proc_dointvec_minmax
);
5907 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5908 sizeof(int), 0644, proc_dointvec_minmax
);
5909 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5910 sizeof(int), 0644, proc_dointvec_minmax
);
5911 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5912 sizeof(int), 0644, proc_dointvec_minmax
);
5913 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5914 sizeof(int), 0644, proc_dointvec_minmax
);
5915 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5916 sizeof(int), 0644, proc_dointvec_minmax
);
5917 set_table_entry(&table
[9], "cache_nice_tries",
5918 &sd
->cache_nice_tries
,
5919 sizeof(int), 0644, proc_dointvec_minmax
);
5920 set_table_entry(&table
[10], "flags", &sd
->flags
,
5921 sizeof(int), 0644, proc_dointvec_minmax
);
5922 /* &table[11] is terminator */
5927 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5929 struct ctl_table
*entry
, *table
;
5930 struct sched_domain
*sd
;
5931 int domain_num
= 0, i
;
5934 for_each_domain(cpu
, sd
)
5936 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5941 for_each_domain(cpu
, sd
) {
5942 snprintf(buf
, 32, "domain%d", i
);
5943 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5945 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5952 static struct ctl_table_header
*sd_sysctl_header
;
5953 static void register_sched_domain_sysctl(void)
5955 int i
, cpu_num
= num_online_cpus();
5956 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5959 WARN_ON(sd_ctl_dir
[0].child
);
5960 sd_ctl_dir
[0].child
= entry
;
5965 for_each_online_cpu(i
) {
5966 snprintf(buf
, 32, "cpu%d", i
);
5967 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5969 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5973 WARN_ON(sd_sysctl_header
);
5974 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5977 /* may be called multiple times per register */
5978 static void unregister_sched_domain_sysctl(void)
5980 if (sd_sysctl_header
)
5981 unregister_sysctl_table(sd_sysctl_header
);
5982 sd_sysctl_header
= NULL
;
5983 if (sd_ctl_dir
[0].child
)
5984 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5987 static void register_sched_domain_sysctl(void)
5990 static void unregister_sched_domain_sysctl(void)
5996 * migration_call - callback that gets triggered when a CPU is added.
5997 * Here we can start up the necessary migration thread for the new CPU.
5999 static int __cpuinit
6000 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6002 struct task_struct
*p
;
6003 int cpu
= (long)hcpu
;
6004 unsigned long flags
;
6009 case CPU_UP_PREPARE
:
6010 case CPU_UP_PREPARE_FROZEN
:
6011 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6014 kthread_bind(p
, cpu
);
6015 /* Must be high prio: stop_machine expects to yield to it. */
6016 rq
= task_rq_lock(p
, &flags
);
6017 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6018 task_rq_unlock(rq
, &flags
);
6019 cpu_rq(cpu
)->migration_thread
= p
;
6023 case CPU_ONLINE_FROZEN
:
6024 /* Strictly unnecessary, as first user will wake it. */
6025 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6027 /* Update our root-domain */
6029 spin_lock_irqsave(&rq
->lock
, flags
);
6031 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6032 cpu_set(cpu
, rq
->rd
->online
);
6034 spin_unlock_irqrestore(&rq
->lock
, flags
);
6037 #ifdef CONFIG_HOTPLUG_CPU
6038 case CPU_UP_CANCELED
:
6039 case CPU_UP_CANCELED_FROZEN
:
6040 if (!cpu_rq(cpu
)->migration_thread
)
6042 /* Unbind it from offline cpu so it can run. Fall thru. */
6043 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6044 any_online_cpu(cpu_online_map
));
6045 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6046 cpu_rq(cpu
)->migration_thread
= NULL
;
6050 case CPU_DEAD_FROZEN
:
6051 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6052 migrate_live_tasks(cpu
);
6054 kthread_stop(rq
->migration_thread
);
6055 rq
->migration_thread
= NULL
;
6056 /* Idle task back to normal (off runqueue, low prio) */
6057 spin_lock_irq(&rq
->lock
);
6058 update_rq_clock(rq
);
6059 deactivate_task(rq
, rq
->idle
, 0);
6060 rq
->idle
->static_prio
= MAX_PRIO
;
6061 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6062 rq
->idle
->sched_class
= &idle_sched_class
;
6063 migrate_dead_tasks(cpu
);
6064 spin_unlock_irq(&rq
->lock
);
6066 migrate_nr_uninterruptible(rq
);
6067 BUG_ON(rq
->nr_running
!= 0);
6070 * No need to migrate the tasks: it was best-effort if
6071 * they didn't take sched_hotcpu_mutex. Just wake up
6074 spin_lock_irq(&rq
->lock
);
6075 while (!list_empty(&rq
->migration_queue
)) {
6076 struct migration_req
*req
;
6078 req
= list_entry(rq
->migration_queue
.next
,
6079 struct migration_req
, list
);
6080 list_del_init(&req
->list
);
6081 complete(&req
->done
);
6083 spin_unlock_irq(&rq
->lock
);
6087 case CPU_DYING_FROZEN
:
6088 /* Update our root-domain */
6090 spin_lock_irqsave(&rq
->lock
, flags
);
6092 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6093 cpu_clear(cpu
, rq
->rd
->online
);
6095 spin_unlock_irqrestore(&rq
->lock
, flags
);
6102 /* Register at highest priority so that task migration (migrate_all_tasks)
6103 * happens before everything else.
6105 static struct notifier_block __cpuinitdata migration_notifier
= {
6106 .notifier_call
= migration_call
,
6110 void __init
migration_init(void)
6112 void *cpu
= (void *)(long)smp_processor_id();
6115 /* Start one for the boot CPU: */
6116 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6117 BUG_ON(err
== NOTIFY_BAD
);
6118 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6119 register_cpu_notifier(&migration_notifier
);
6125 #ifdef CONFIG_SCHED_DEBUG
6127 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6128 cpumask_t
*groupmask
)
6130 struct sched_group
*group
= sd
->groups
;
6133 cpulist_scnprintf(str
, sizeof(str
), sd
->span
);
6134 cpus_clear(*groupmask
);
6136 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6138 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6139 printk("does not load-balance\n");
6141 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6146 printk(KERN_CONT
"span %s\n", str
);
6148 if (!cpu_isset(cpu
, sd
->span
)) {
6149 printk(KERN_ERR
"ERROR: domain->span does not contain "
6152 if (!cpu_isset(cpu
, group
->cpumask
)) {
6153 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6157 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6161 printk(KERN_ERR
"ERROR: group is NULL\n");
6165 if (!group
->__cpu_power
) {
6166 printk(KERN_CONT
"\n");
6167 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6172 if (!cpus_weight(group
->cpumask
)) {
6173 printk(KERN_CONT
"\n");
6174 printk(KERN_ERR
"ERROR: empty group\n");
6178 if (cpus_intersects(*groupmask
, group
->cpumask
)) {
6179 printk(KERN_CONT
"\n");
6180 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6184 cpus_or(*groupmask
, *groupmask
, group
->cpumask
);
6186 cpulist_scnprintf(str
, sizeof(str
), group
->cpumask
);
6187 printk(KERN_CONT
" %s", str
);
6189 group
= group
->next
;
6190 } while (group
!= sd
->groups
);
6191 printk(KERN_CONT
"\n");
6193 if (!cpus_equal(sd
->span
, *groupmask
))
6194 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6196 if (sd
->parent
&& !cpus_subset(*groupmask
, sd
->parent
->span
))
6197 printk(KERN_ERR
"ERROR: parent span is not a superset "
6198 "of domain->span\n");
6202 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6204 cpumask_t
*groupmask
;
6208 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6212 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6214 groupmask
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
6216 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6221 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6231 # define sched_domain_debug(sd, cpu) do { } while (0)
6234 static int sd_degenerate(struct sched_domain
*sd
)
6236 if (cpus_weight(sd
->span
) == 1)
6239 /* Following flags need at least 2 groups */
6240 if (sd
->flags
& (SD_LOAD_BALANCE
|
6241 SD_BALANCE_NEWIDLE
|
6245 SD_SHARE_PKG_RESOURCES
)) {
6246 if (sd
->groups
!= sd
->groups
->next
)
6250 /* Following flags don't use groups */
6251 if (sd
->flags
& (SD_WAKE_IDLE
|
6260 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6262 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6264 if (sd_degenerate(parent
))
6267 if (!cpus_equal(sd
->span
, parent
->span
))
6270 /* Does parent contain flags not in child? */
6271 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6272 if (cflags
& SD_WAKE_AFFINE
)
6273 pflags
&= ~SD_WAKE_BALANCE
;
6274 /* Flags needing groups don't count if only 1 group in parent */
6275 if (parent
->groups
== parent
->groups
->next
) {
6276 pflags
&= ~(SD_LOAD_BALANCE
|
6277 SD_BALANCE_NEWIDLE
|
6281 SD_SHARE_PKG_RESOURCES
);
6283 if (~cflags
& pflags
)
6289 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6291 unsigned long flags
;
6292 const struct sched_class
*class;
6294 spin_lock_irqsave(&rq
->lock
, flags
);
6297 struct root_domain
*old_rd
= rq
->rd
;
6299 for (class = sched_class_highest
; class; class = class->next
) {
6300 if (class->leave_domain
)
6301 class->leave_domain(rq
);
6304 cpu_clear(rq
->cpu
, old_rd
->span
);
6305 cpu_clear(rq
->cpu
, old_rd
->online
);
6307 if (atomic_dec_and_test(&old_rd
->refcount
))
6311 atomic_inc(&rd
->refcount
);
6314 cpu_set(rq
->cpu
, rd
->span
);
6315 if (cpu_isset(rq
->cpu
, cpu_online_map
))
6316 cpu_set(rq
->cpu
, rd
->online
);
6318 for (class = sched_class_highest
; class; class = class->next
) {
6319 if (class->join_domain
)
6320 class->join_domain(rq
);
6323 spin_unlock_irqrestore(&rq
->lock
, flags
);
6326 static void init_rootdomain(struct root_domain
*rd
)
6328 memset(rd
, 0, sizeof(*rd
));
6330 cpus_clear(rd
->span
);
6331 cpus_clear(rd
->online
);
6334 static void init_defrootdomain(void)
6336 init_rootdomain(&def_root_domain
);
6337 atomic_set(&def_root_domain
.refcount
, 1);
6340 static struct root_domain
*alloc_rootdomain(void)
6342 struct root_domain
*rd
;
6344 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6348 init_rootdomain(rd
);
6354 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6355 * hold the hotplug lock.
6358 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6360 struct rq
*rq
= cpu_rq(cpu
);
6361 struct sched_domain
*tmp
;
6363 /* Remove the sched domains which do not contribute to scheduling. */
6364 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
) {
6365 struct sched_domain
*parent
= tmp
->parent
;
6368 if (sd_parent_degenerate(tmp
, parent
)) {
6369 tmp
->parent
= parent
->parent
;
6371 parent
->parent
->child
= tmp
;
6375 if (sd
&& sd_degenerate(sd
)) {
6381 sched_domain_debug(sd
, cpu
);
6383 rq_attach_root(rq
, rd
);
6384 rcu_assign_pointer(rq
->sd
, sd
);
6387 /* cpus with isolated domains */
6388 static cpumask_t cpu_isolated_map
= CPU_MASK_NONE
;
6390 /* Setup the mask of cpus configured for isolated domains */
6391 static int __init
isolated_cpu_setup(char *str
)
6393 int ints
[NR_CPUS
], i
;
6395 str
= get_options(str
, ARRAY_SIZE(ints
), ints
);
6396 cpus_clear(cpu_isolated_map
);
6397 for (i
= 1; i
<= ints
[0]; i
++)
6398 if (ints
[i
] < NR_CPUS
)
6399 cpu_set(ints
[i
], cpu_isolated_map
);
6403 __setup("isolcpus=", isolated_cpu_setup
);
6406 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6407 * to a function which identifies what group(along with sched group) a CPU
6408 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6409 * (due to the fact that we keep track of groups covered with a cpumask_t).
6411 * init_sched_build_groups will build a circular linked list of the groups
6412 * covered by the given span, and will set each group's ->cpumask correctly,
6413 * and ->cpu_power to 0.
6416 init_sched_build_groups(const cpumask_t
*span
, const cpumask_t
*cpu_map
,
6417 int (*group_fn
)(int cpu
, const cpumask_t
*cpu_map
,
6418 struct sched_group
**sg
,
6419 cpumask_t
*tmpmask
),
6420 cpumask_t
*covered
, cpumask_t
*tmpmask
)
6422 struct sched_group
*first
= NULL
, *last
= NULL
;
6425 cpus_clear(*covered
);
6427 for_each_cpu_mask(i
, *span
) {
6428 struct sched_group
*sg
;
6429 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6432 if (cpu_isset(i
, *covered
))
6435 cpus_clear(sg
->cpumask
);
6436 sg
->__cpu_power
= 0;
6438 for_each_cpu_mask(j
, *span
) {
6439 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6442 cpu_set(j
, *covered
);
6443 cpu_set(j
, sg
->cpumask
);
6454 #define SD_NODES_PER_DOMAIN 16
6459 * find_next_best_node - find the next node to include in a sched_domain
6460 * @node: node whose sched_domain we're building
6461 * @used_nodes: nodes already in the sched_domain
6463 * Find the next node to include in a given scheduling domain. Simply
6464 * finds the closest node not already in the @used_nodes map.
6466 * Should use nodemask_t.
6468 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6470 int i
, n
, val
, min_val
, best_node
= 0;
6474 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6475 /* Start at @node */
6476 n
= (node
+ i
) % MAX_NUMNODES
;
6478 if (!nr_cpus_node(n
))
6481 /* Skip already used nodes */
6482 if (node_isset(n
, *used_nodes
))
6485 /* Simple min distance search */
6486 val
= node_distance(node
, n
);
6488 if (val
< min_val
) {
6494 node_set(best_node
, *used_nodes
);
6499 * sched_domain_node_span - get a cpumask for a node's sched_domain
6500 * @node: node whose cpumask we're constructing
6502 * Given a node, construct a good cpumask for its sched_domain to span. It
6503 * should be one that prevents unnecessary balancing, but also spreads tasks
6506 static void sched_domain_node_span(int node
, cpumask_t
*span
)
6508 nodemask_t used_nodes
;
6509 node_to_cpumask_ptr(nodemask
, node
);
6513 nodes_clear(used_nodes
);
6515 cpus_or(*span
, *span
, *nodemask
);
6516 node_set(node
, used_nodes
);
6518 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6519 int next_node
= find_next_best_node(node
, &used_nodes
);
6521 node_to_cpumask_ptr_next(nodemask
, next_node
);
6522 cpus_or(*span
, *span
, *nodemask
);
6527 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6530 * SMT sched-domains:
6532 #ifdef CONFIG_SCHED_SMT
6533 static DEFINE_PER_CPU(struct sched_domain
, cpu_domains
);
6534 static DEFINE_PER_CPU(struct sched_group
, sched_group_cpus
);
6537 cpu_to_cpu_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6541 *sg
= &per_cpu(sched_group_cpus
, cpu
);
6547 * multi-core sched-domains:
6549 #ifdef CONFIG_SCHED_MC
6550 static DEFINE_PER_CPU(struct sched_domain
, core_domains
);
6551 static DEFINE_PER_CPU(struct sched_group
, sched_group_core
);
6554 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6556 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6561 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6562 cpus_and(*mask
, *mask
, *cpu_map
);
6563 group
= first_cpu(*mask
);
6565 *sg
= &per_cpu(sched_group_core
, group
);
6568 #elif defined(CONFIG_SCHED_MC)
6570 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6574 *sg
= &per_cpu(sched_group_core
, cpu
);
6579 static DEFINE_PER_CPU(struct sched_domain
, phys_domains
);
6580 static DEFINE_PER_CPU(struct sched_group
, sched_group_phys
);
6583 cpu_to_phys_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6587 #ifdef CONFIG_SCHED_MC
6588 *mask
= cpu_coregroup_map(cpu
);
6589 cpus_and(*mask
, *mask
, *cpu_map
);
6590 group
= first_cpu(*mask
);
6591 #elif defined(CONFIG_SCHED_SMT)
6592 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6593 cpus_and(*mask
, *mask
, *cpu_map
);
6594 group
= first_cpu(*mask
);
6599 *sg
= &per_cpu(sched_group_phys
, group
);
6605 * The init_sched_build_groups can't handle what we want to do with node
6606 * groups, so roll our own. Now each node has its own list of groups which
6607 * gets dynamically allocated.
6609 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
6610 static struct sched_group
***sched_group_nodes_bycpu
;
6612 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
6613 static DEFINE_PER_CPU(struct sched_group
, sched_group_allnodes
);
6615 static int cpu_to_allnodes_group(int cpu
, const cpumask_t
*cpu_map
,
6616 struct sched_group
**sg
, cpumask_t
*nodemask
)
6620 *nodemask
= node_to_cpumask(cpu_to_node(cpu
));
6621 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6622 group
= first_cpu(*nodemask
);
6625 *sg
= &per_cpu(sched_group_allnodes
, group
);
6629 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6631 struct sched_group
*sg
= group_head
;
6637 for_each_cpu_mask(j
, sg
->cpumask
) {
6638 struct sched_domain
*sd
;
6640 sd
= &per_cpu(phys_domains
, j
);
6641 if (j
!= first_cpu(sd
->groups
->cpumask
)) {
6643 * Only add "power" once for each
6649 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
6652 } while (sg
!= group_head
);
6657 /* Free memory allocated for various sched_group structures */
6658 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6662 for_each_cpu_mask(cpu
, *cpu_map
) {
6663 struct sched_group
**sched_group_nodes
6664 = sched_group_nodes_bycpu
[cpu
];
6666 if (!sched_group_nodes
)
6669 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6670 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6672 *nodemask
= node_to_cpumask(i
);
6673 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6674 if (cpus_empty(*nodemask
))
6684 if (oldsg
!= sched_group_nodes
[i
])
6687 kfree(sched_group_nodes
);
6688 sched_group_nodes_bycpu
[cpu
] = NULL
;
6692 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6698 * Initialize sched groups cpu_power.
6700 * cpu_power indicates the capacity of sched group, which is used while
6701 * distributing the load between different sched groups in a sched domain.
6702 * Typically cpu_power for all the groups in a sched domain will be same unless
6703 * there are asymmetries in the topology. If there are asymmetries, group
6704 * having more cpu_power will pickup more load compared to the group having
6707 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6708 * the maximum number of tasks a group can handle in the presence of other idle
6709 * or lightly loaded groups in the same sched domain.
6711 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6713 struct sched_domain
*child
;
6714 struct sched_group
*group
;
6716 WARN_ON(!sd
|| !sd
->groups
);
6718 if (cpu
!= first_cpu(sd
->groups
->cpumask
))
6723 sd
->groups
->__cpu_power
= 0;
6726 * For perf policy, if the groups in child domain share resources
6727 * (for example cores sharing some portions of the cache hierarchy
6728 * or SMT), then set this domain groups cpu_power such that each group
6729 * can handle only one task, when there are other idle groups in the
6730 * same sched domain.
6732 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
6734 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
6735 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
6740 * add cpu_power of each child group to this groups cpu_power
6742 group
= child
->groups
;
6744 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
6745 group
= group
->next
;
6746 } while (group
!= child
->groups
);
6750 * Initializers for schedule domains
6751 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6754 #define SD_INIT(sd, type) sd_init_##type(sd)
6755 #define SD_INIT_FUNC(type) \
6756 static noinline void sd_init_##type(struct sched_domain *sd) \
6758 memset(sd, 0, sizeof(*sd)); \
6759 *sd = SD_##type##_INIT; \
6764 SD_INIT_FUNC(ALLNODES
)
6767 #ifdef CONFIG_SCHED_SMT
6768 SD_INIT_FUNC(SIBLING
)
6770 #ifdef CONFIG_SCHED_MC
6775 * To minimize stack usage kmalloc room for cpumasks and share the
6776 * space as the usage in build_sched_domains() dictates. Used only
6777 * if the amount of space is significant.
6780 cpumask_t tmpmask
; /* make this one first */
6783 cpumask_t this_sibling_map
;
6784 cpumask_t this_core_map
;
6786 cpumask_t send_covered
;
6789 cpumask_t domainspan
;
6791 cpumask_t notcovered
;
6796 #define SCHED_CPUMASK_ALLOC 1
6797 #define SCHED_CPUMASK_FREE(v) kfree(v)
6798 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
6800 #define SCHED_CPUMASK_ALLOC 0
6801 #define SCHED_CPUMASK_FREE(v)
6802 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
6805 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
6806 ((unsigned long)(a) + offsetof(struct allmasks, v))
6809 * Build sched domains for a given set of cpus and attach the sched domains
6810 * to the individual cpus
6812 static int build_sched_domains(const cpumask_t
*cpu_map
)
6815 struct root_domain
*rd
;
6816 SCHED_CPUMASK_DECLARE(allmasks
);
6819 struct sched_group
**sched_group_nodes
= NULL
;
6820 int sd_allnodes
= 0;
6823 * Allocate the per-node list of sched groups
6825 sched_group_nodes
= kcalloc(MAX_NUMNODES
, sizeof(struct sched_group
*),
6827 if (!sched_group_nodes
) {
6828 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6833 rd
= alloc_rootdomain();
6835 printk(KERN_WARNING
"Cannot alloc root domain\n");
6837 kfree(sched_group_nodes
);
6842 #if SCHED_CPUMASK_ALLOC
6843 /* get space for all scratch cpumask variables */
6844 allmasks
= kmalloc(sizeof(*allmasks
), GFP_KERNEL
);
6846 printk(KERN_WARNING
"Cannot alloc cpumask array\n");
6849 kfree(sched_group_nodes
);
6854 tmpmask
= (cpumask_t
*)allmasks
;
6858 sched_group_nodes_bycpu
[first_cpu(*cpu_map
)] = sched_group_nodes
;
6862 * Set up domains for cpus specified by the cpu_map.
6864 for_each_cpu_mask(i
, *cpu_map
) {
6865 struct sched_domain
*sd
= NULL
, *p
;
6866 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6868 *nodemask
= node_to_cpumask(cpu_to_node(i
));
6869 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6872 if (cpus_weight(*cpu_map
) >
6873 SD_NODES_PER_DOMAIN
*cpus_weight(*nodemask
)) {
6874 sd
= &per_cpu(allnodes_domains
, i
);
6875 SD_INIT(sd
, ALLNODES
);
6876 sd
->span
= *cpu_map
;
6877 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6883 sd
= &per_cpu(node_domains
, i
);
6885 sched_domain_node_span(cpu_to_node(i
), &sd
->span
);
6889 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6893 sd
= &per_cpu(phys_domains
, i
);
6895 sd
->span
= *nodemask
;
6899 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6901 #ifdef CONFIG_SCHED_MC
6903 sd
= &per_cpu(core_domains
, i
);
6905 sd
->span
= cpu_coregroup_map(i
);
6906 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6909 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6912 #ifdef CONFIG_SCHED_SMT
6914 sd
= &per_cpu(cpu_domains
, i
);
6915 SD_INIT(sd
, SIBLING
);
6916 sd
->span
= per_cpu(cpu_sibling_map
, i
);
6917 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6920 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6924 #ifdef CONFIG_SCHED_SMT
6925 /* Set up CPU (sibling) groups */
6926 for_each_cpu_mask(i
, *cpu_map
) {
6927 SCHED_CPUMASK_VAR(this_sibling_map
, allmasks
);
6928 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6930 *this_sibling_map
= per_cpu(cpu_sibling_map
, i
);
6931 cpus_and(*this_sibling_map
, *this_sibling_map
, *cpu_map
);
6932 if (i
!= first_cpu(*this_sibling_map
))
6935 init_sched_build_groups(this_sibling_map
, cpu_map
,
6937 send_covered
, tmpmask
);
6941 #ifdef CONFIG_SCHED_MC
6942 /* Set up multi-core groups */
6943 for_each_cpu_mask(i
, *cpu_map
) {
6944 SCHED_CPUMASK_VAR(this_core_map
, allmasks
);
6945 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6947 *this_core_map
= cpu_coregroup_map(i
);
6948 cpus_and(*this_core_map
, *this_core_map
, *cpu_map
);
6949 if (i
!= first_cpu(*this_core_map
))
6952 init_sched_build_groups(this_core_map
, cpu_map
,
6954 send_covered
, tmpmask
);
6958 /* Set up physical groups */
6959 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6960 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6961 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6963 *nodemask
= node_to_cpumask(i
);
6964 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6965 if (cpus_empty(*nodemask
))
6968 init_sched_build_groups(nodemask
, cpu_map
,
6970 send_covered
, tmpmask
);
6974 /* Set up node groups */
6976 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6978 init_sched_build_groups(cpu_map
, cpu_map
,
6979 &cpu_to_allnodes_group
,
6980 send_covered
, tmpmask
);
6983 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6984 /* Set up node groups */
6985 struct sched_group
*sg
, *prev
;
6986 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6987 SCHED_CPUMASK_VAR(domainspan
, allmasks
);
6988 SCHED_CPUMASK_VAR(covered
, allmasks
);
6991 *nodemask
= node_to_cpumask(i
);
6992 cpus_clear(*covered
);
6994 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6995 if (cpus_empty(*nodemask
)) {
6996 sched_group_nodes
[i
] = NULL
;
7000 sched_domain_node_span(i
, domainspan
);
7001 cpus_and(*domainspan
, *domainspan
, *cpu_map
);
7003 sg
= kmalloc_node(sizeof(struct sched_group
), GFP_KERNEL
, i
);
7005 printk(KERN_WARNING
"Can not alloc domain group for "
7009 sched_group_nodes
[i
] = sg
;
7010 for_each_cpu_mask(j
, *nodemask
) {
7011 struct sched_domain
*sd
;
7013 sd
= &per_cpu(node_domains
, j
);
7016 sg
->__cpu_power
= 0;
7017 sg
->cpumask
= *nodemask
;
7019 cpus_or(*covered
, *covered
, *nodemask
);
7022 for (j
= 0; j
< MAX_NUMNODES
; j
++) {
7023 SCHED_CPUMASK_VAR(notcovered
, allmasks
);
7024 int n
= (i
+ j
) % MAX_NUMNODES
;
7025 node_to_cpumask_ptr(pnodemask
, n
);
7027 cpus_complement(*notcovered
, *covered
);
7028 cpus_and(*tmpmask
, *notcovered
, *cpu_map
);
7029 cpus_and(*tmpmask
, *tmpmask
, *domainspan
);
7030 if (cpus_empty(*tmpmask
))
7033 cpus_and(*tmpmask
, *tmpmask
, *pnodemask
);
7034 if (cpus_empty(*tmpmask
))
7037 sg
= kmalloc_node(sizeof(struct sched_group
),
7041 "Can not alloc domain group for node %d\n", j
);
7044 sg
->__cpu_power
= 0;
7045 sg
->cpumask
= *tmpmask
;
7046 sg
->next
= prev
->next
;
7047 cpus_or(*covered
, *covered
, *tmpmask
);
7054 /* Calculate CPU power for physical packages and nodes */
7055 #ifdef CONFIG_SCHED_SMT
7056 for_each_cpu_mask(i
, *cpu_map
) {
7057 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
);
7059 init_sched_groups_power(i
, sd
);
7062 #ifdef CONFIG_SCHED_MC
7063 for_each_cpu_mask(i
, *cpu_map
) {
7064 struct sched_domain
*sd
= &per_cpu(core_domains
, i
);
7066 init_sched_groups_power(i
, sd
);
7070 for_each_cpu_mask(i
, *cpu_map
) {
7071 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
);
7073 init_sched_groups_power(i
, sd
);
7077 for (i
= 0; i
< MAX_NUMNODES
; i
++)
7078 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7081 struct sched_group
*sg
;
7083 cpu_to_allnodes_group(first_cpu(*cpu_map
), cpu_map
, &sg
,
7085 init_numa_sched_groups_power(sg
);
7089 /* Attach the domains */
7090 for_each_cpu_mask(i
, *cpu_map
) {
7091 struct sched_domain
*sd
;
7092 #ifdef CONFIG_SCHED_SMT
7093 sd
= &per_cpu(cpu_domains
, i
);
7094 #elif defined(CONFIG_SCHED_MC)
7095 sd
= &per_cpu(core_domains
, i
);
7097 sd
= &per_cpu(phys_domains
, i
);
7099 cpu_attach_domain(sd
, rd
, i
);
7102 SCHED_CPUMASK_FREE((void *)allmasks
);
7107 free_sched_groups(cpu_map
, tmpmask
);
7108 SCHED_CPUMASK_FREE((void *)allmasks
);
7113 static cpumask_t
*doms_cur
; /* current sched domains */
7114 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7117 * Special case: If a kmalloc of a doms_cur partition (array of
7118 * cpumask_t) fails, then fallback to a single sched domain,
7119 * as determined by the single cpumask_t fallback_doms.
7121 static cpumask_t fallback_doms
;
7123 void __attribute__((weak
)) arch_update_cpu_topology(void)
7128 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7129 * For now this just excludes isolated cpus, but could be used to
7130 * exclude other special cases in the future.
7132 static int arch_init_sched_domains(const cpumask_t
*cpu_map
)
7136 arch_update_cpu_topology();
7138 doms_cur
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
7140 doms_cur
= &fallback_doms
;
7141 cpus_andnot(*doms_cur
, *cpu_map
, cpu_isolated_map
);
7142 err
= build_sched_domains(doms_cur
);
7143 register_sched_domain_sysctl();
7148 static void arch_destroy_sched_domains(const cpumask_t
*cpu_map
,
7151 free_sched_groups(cpu_map
, tmpmask
);
7155 * Detach sched domains from a group of cpus specified in cpu_map
7156 * These cpus will now be attached to the NULL domain
7158 static void detach_destroy_domains(const cpumask_t
*cpu_map
)
7163 unregister_sched_domain_sysctl();
7165 for_each_cpu_mask(i
, *cpu_map
)
7166 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7167 synchronize_sched();
7168 arch_destroy_sched_domains(cpu_map
, &tmpmask
);
7172 * Partition sched domains as specified by the 'ndoms_new'
7173 * cpumasks in the array doms_new[] of cpumasks. This compares
7174 * doms_new[] to the current sched domain partitioning, doms_cur[].
7175 * It destroys each deleted domain and builds each new domain.
7177 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7178 * The masks don't intersect (don't overlap.) We should setup one
7179 * sched domain for each mask. CPUs not in any of the cpumasks will
7180 * not be load balanced. If the same cpumask appears both in the
7181 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7184 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7185 * ownership of it and will kfree it when done with it. If the caller
7186 * failed the kmalloc call, then it can pass in doms_new == NULL,
7187 * and partition_sched_domains() will fallback to the single partition
7190 * Call with hotplug lock held
7192 void partition_sched_domains(int ndoms_new
, cpumask_t
*doms_new
)
7198 /* always unregister in case we don't destroy any domains */
7199 unregister_sched_domain_sysctl();
7201 if (doms_new
== NULL
) {
7203 doms_new
= &fallback_doms
;
7204 cpus_andnot(doms_new
[0], cpu_online_map
, cpu_isolated_map
);
7207 /* Destroy deleted domains */
7208 for (i
= 0; i
< ndoms_cur
; i
++) {
7209 for (j
= 0; j
< ndoms_new
; j
++) {
7210 if (cpus_equal(doms_cur
[i
], doms_new
[j
]))
7213 /* no match - a current sched domain not in new doms_new[] */
7214 detach_destroy_domains(doms_cur
+ i
);
7219 /* Build new domains */
7220 for (i
= 0; i
< ndoms_new
; i
++) {
7221 for (j
= 0; j
< ndoms_cur
; j
++) {
7222 if (cpus_equal(doms_new
[i
], doms_cur
[j
]))
7225 /* no match - add a new doms_new */
7226 build_sched_domains(doms_new
+ i
);
7231 /* Remember the new sched domains */
7232 if (doms_cur
!= &fallback_doms
)
7234 doms_cur
= doms_new
;
7235 ndoms_cur
= ndoms_new
;
7237 register_sched_domain_sysctl();
7242 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7243 int arch_reinit_sched_domains(void)
7248 detach_destroy_domains(&cpu_online_map
);
7249 err
= arch_init_sched_domains(&cpu_online_map
);
7255 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7259 if (buf
[0] != '0' && buf
[0] != '1')
7263 sched_smt_power_savings
= (buf
[0] == '1');
7265 sched_mc_power_savings
= (buf
[0] == '1');
7267 ret
= arch_reinit_sched_domains();
7269 return ret
? ret
: count
;
7272 #ifdef CONFIG_SCHED_MC
7273 static ssize_t
sched_mc_power_savings_show(struct sys_device
*dev
, char *page
)
7275 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7277 static ssize_t
sched_mc_power_savings_store(struct sys_device
*dev
,
7278 const char *buf
, size_t count
)
7280 return sched_power_savings_store(buf
, count
, 0);
7282 static SYSDEV_ATTR(sched_mc_power_savings
, 0644, sched_mc_power_savings_show
,
7283 sched_mc_power_savings_store
);
7286 #ifdef CONFIG_SCHED_SMT
7287 static ssize_t
sched_smt_power_savings_show(struct sys_device
*dev
, char *page
)
7289 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7291 static ssize_t
sched_smt_power_savings_store(struct sys_device
*dev
,
7292 const char *buf
, size_t count
)
7294 return sched_power_savings_store(buf
, count
, 1);
7296 static SYSDEV_ATTR(sched_smt_power_savings
, 0644, sched_smt_power_savings_show
,
7297 sched_smt_power_savings_store
);
7300 int sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7304 #ifdef CONFIG_SCHED_SMT
7306 err
= sysfs_create_file(&cls
->kset
.kobj
,
7307 &attr_sched_smt_power_savings
.attr
);
7309 #ifdef CONFIG_SCHED_MC
7310 if (!err
&& mc_capable())
7311 err
= sysfs_create_file(&cls
->kset
.kobj
,
7312 &attr_sched_mc_power_savings
.attr
);
7319 * Force a reinitialization of the sched domains hierarchy. The domains
7320 * and groups cannot be updated in place without racing with the balancing
7321 * code, so we temporarily attach all running cpus to the NULL domain
7322 * which will prevent rebalancing while the sched domains are recalculated.
7324 static int update_sched_domains(struct notifier_block
*nfb
,
7325 unsigned long action
, void *hcpu
)
7328 case CPU_UP_PREPARE
:
7329 case CPU_UP_PREPARE_FROZEN
:
7330 case CPU_DOWN_PREPARE
:
7331 case CPU_DOWN_PREPARE_FROZEN
:
7332 detach_destroy_domains(&cpu_online_map
);
7335 case CPU_UP_CANCELED
:
7336 case CPU_UP_CANCELED_FROZEN
:
7337 case CPU_DOWN_FAILED
:
7338 case CPU_DOWN_FAILED_FROZEN
:
7340 case CPU_ONLINE_FROZEN
:
7342 case CPU_DEAD_FROZEN
:
7344 * Fall through and re-initialise the domains.
7351 /* The hotplug lock is already held by cpu_up/cpu_down */
7352 arch_init_sched_domains(&cpu_online_map
);
7357 void __init
sched_init_smp(void)
7359 cpumask_t non_isolated_cpus
;
7361 #if defined(CONFIG_NUMA)
7362 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7364 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7367 arch_init_sched_domains(&cpu_online_map
);
7368 cpus_andnot(non_isolated_cpus
, cpu_possible_map
, cpu_isolated_map
);
7369 if (cpus_empty(non_isolated_cpus
))
7370 cpu_set(smp_processor_id(), non_isolated_cpus
);
7372 /* XXX: Theoretical race here - CPU may be hotplugged now */
7373 hotcpu_notifier(update_sched_domains
, 0);
7375 /* Move init over to a non-isolated CPU */
7376 if (set_cpus_allowed_ptr(current
, &non_isolated_cpus
) < 0)
7378 sched_init_granularity();
7381 void __init
sched_init_smp(void)
7383 #if defined(CONFIG_NUMA)
7384 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7386 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7388 sched_init_granularity();
7390 #endif /* CONFIG_SMP */
7392 int in_sched_functions(unsigned long addr
)
7394 return in_lock_functions(addr
) ||
7395 (addr
>= (unsigned long)__sched_text_start
7396 && addr
< (unsigned long)__sched_text_end
);
7399 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7401 cfs_rq
->tasks_timeline
= RB_ROOT
;
7402 #ifdef CONFIG_FAIR_GROUP_SCHED
7405 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7408 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7410 struct rt_prio_array
*array
;
7413 array
= &rt_rq
->active
;
7414 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7415 INIT_LIST_HEAD(array
->queue
+ i
);
7416 __clear_bit(i
, array
->bitmap
);
7418 /* delimiter for bitsearch: */
7419 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7421 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7422 rt_rq
->highest_prio
= MAX_RT_PRIO
;
7425 rt_rq
->rt_nr_migratory
= 0;
7426 rt_rq
->overloaded
= 0;
7430 rt_rq
->rt_throttled
= 0;
7431 rt_rq
->rt_runtime
= 0;
7432 spin_lock_init(&rt_rq
->rt_runtime_lock
);
7434 #ifdef CONFIG_RT_GROUP_SCHED
7435 rt_rq
->rt_nr_boosted
= 0;
7440 #ifdef CONFIG_FAIR_GROUP_SCHED
7441 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7442 struct sched_entity
*se
, int cpu
, int add
,
7443 struct sched_entity
*parent
)
7445 struct rq
*rq
= cpu_rq(cpu
);
7446 tg
->cfs_rq
[cpu
] = cfs_rq
;
7447 init_cfs_rq(cfs_rq
, rq
);
7450 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7453 /* se could be NULL for init_task_group */
7458 se
->cfs_rq
= &rq
->cfs
;
7460 se
->cfs_rq
= parent
->my_q
;
7463 se
->load
.weight
= tg
->shares
;
7464 se
->load
.inv_weight
= div64_64(1ULL<<32, se
->load
.weight
);
7465 se
->parent
= parent
;
7469 #ifdef CONFIG_RT_GROUP_SCHED
7470 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7471 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
7472 struct sched_rt_entity
*parent
)
7474 struct rq
*rq
= cpu_rq(cpu
);
7476 tg
->rt_rq
[cpu
] = rt_rq
;
7477 init_rt_rq(rt_rq
, rq
);
7479 rt_rq
->rt_se
= rt_se
;
7480 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7482 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7484 tg
->rt_se
[cpu
] = rt_se
;
7489 rt_se
->rt_rq
= &rq
->rt
;
7491 rt_se
->rt_rq
= parent
->my_q
;
7493 rt_se
->rt_rq
= &rq
->rt
;
7494 rt_se
->my_q
= rt_rq
;
7495 rt_se
->parent
= parent
;
7496 INIT_LIST_HEAD(&rt_se
->run_list
);
7500 void __init
sched_init(void)
7503 unsigned long alloc_size
= 0, ptr
;
7505 #ifdef CONFIG_FAIR_GROUP_SCHED
7506 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7508 #ifdef CONFIG_RT_GROUP_SCHED
7509 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7512 * As sched_init() is called before page_alloc is setup,
7513 * we use alloc_bootmem().
7516 ptr
= (unsigned long)alloc_bootmem_low(alloc_size
);
7518 #ifdef CONFIG_FAIR_GROUP_SCHED
7519 init_task_group
.se
= (struct sched_entity
**)ptr
;
7520 ptr
+= nr_cpu_ids
* sizeof(void **);
7522 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7523 ptr
+= nr_cpu_ids
* sizeof(void **);
7525 #ifdef CONFIG_RT_GROUP_SCHED
7526 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7527 ptr
+= nr_cpu_ids
* sizeof(void **);
7529 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7534 init_defrootdomain();
7537 init_rt_bandwidth(&def_rt_bandwidth
,
7538 global_rt_period(), global_rt_runtime());
7540 #ifdef CONFIG_RT_GROUP_SCHED
7541 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7542 global_rt_period(), global_rt_runtime());
7545 #ifdef CONFIG_GROUP_SCHED
7546 list_add(&init_task_group
.list
, &task_groups
);
7549 for_each_possible_cpu(i
) {
7553 spin_lock_init(&rq
->lock
);
7554 lockdep_set_class(&rq
->lock
, &rq
->rq_lock_key
);
7557 update_last_tick_seen(rq
);
7558 init_cfs_rq(&rq
->cfs
, rq
);
7559 init_rt_rq(&rq
->rt
, rq
);
7560 #ifdef CONFIG_FAIR_GROUP_SCHED
7561 init_task_group
.shares
= init_task_group_load
;
7562 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7563 #ifdef CONFIG_CGROUP_SCHED
7565 * How much cpu bandwidth does init_task_group get?
7567 * In case of task-groups formed thr' the cgroup filesystem, it
7568 * gets 100% of the cpu resources in the system. This overall
7569 * system cpu resource is divided among the tasks of
7570 * init_task_group and its child task-groups in a fair manner,
7571 * based on each entity's (task or task-group's) weight
7572 * (se->load.weight).
7574 * In other words, if init_task_group has 10 tasks of weight
7575 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7576 * then A0's share of the cpu resource is:
7578 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7580 * We achieve this by letting init_task_group's tasks sit
7581 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7583 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
7584 #elif defined CONFIG_USER_SCHED
7586 * In case of task-groups formed thr' the user id of tasks,
7587 * init_task_group represents tasks belonging to root user.
7588 * Hence it forms a sibling of all subsequent groups formed.
7589 * In this case, init_task_group gets only a fraction of overall
7590 * system cpu resource, based on the weight assigned to root
7591 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
7592 * by letting tasks of init_task_group sit in a separate cfs_rq
7593 * (init_cfs_rq) and having one entity represent this group of
7594 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
7596 init_tg_cfs_entry(&init_task_group
,
7597 &per_cpu(init_cfs_rq
, i
),
7598 &per_cpu(init_sched_entity
, i
), i
, 1, NULL
);
7601 #endif /* CONFIG_FAIR_GROUP_SCHED */
7603 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7604 #ifdef CONFIG_RT_GROUP_SCHED
7605 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7606 #ifdef CONFIG_CGROUP_SCHED
7607 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
7608 #elif defined CONFIG_USER_SCHED
7609 init_tg_rt_entry(&init_task_group
,
7610 &per_cpu(init_rt_rq
, i
),
7611 &per_cpu(init_sched_rt_entity
, i
), i
, 1, NULL
);
7615 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7616 rq
->cpu_load
[j
] = 0;
7620 rq
->active_balance
= 0;
7621 rq
->next_balance
= jiffies
;
7624 rq
->migration_thread
= NULL
;
7625 INIT_LIST_HEAD(&rq
->migration_queue
);
7626 rq_attach_root(rq
, &def_root_domain
);
7629 atomic_set(&rq
->nr_iowait
, 0);
7632 set_load_weight(&init_task
);
7634 #ifdef CONFIG_PREEMPT_NOTIFIERS
7635 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7639 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
, NULL
);
7642 #ifdef CONFIG_RT_MUTEXES
7643 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7647 * The boot idle thread does lazy MMU switching as well:
7649 atomic_inc(&init_mm
.mm_count
);
7650 enter_lazy_tlb(&init_mm
, current
);
7653 * Make us the idle thread. Technically, schedule() should not be
7654 * called from this thread, however somewhere below it might be,
7655 * but because we are the idle thread, we just pick up running again
7656 * when this runqueue becomes "idle".
7658 init_idle(current
, smp_processor_id());
7660 * During early bootup we pretend to be a normal task:
7662 current
->sched_class
= &fair_sched_class
;
7664 scheduler_running
= 1;
7667 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7668 void __might_sleep(char *file
, int line
)
7671 static unsigned long prev_jiffy
; /* ratelimiting */
7673 if ((in_atomic() || irqs_disabled()) &&
7674 system_state
== SYSTEM_RUNNING
&& !oops_in_progress
) {
7675 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7677 prev_jiffy
= jiffies
;
7678 printk(KERN_ERR
"BUG: sleeping function called from invalid"
7679 " context at %s:%d\n", file
, line
);
7680 printk("in_atomic():%d, irqs_disabled():%d\n",
7681 in_atomic(), irqs_disabled());
7682 debug_show_held_locks(current
);
7683 if (irqs_disabled())
7684 print_irqtrace_events(current
);
7689 EXPORT_SYMBOL(__might_sleep
);
7692 #ifdef CONFIG_MAGIC_SYSRQ
7693 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7696 update_rq_clock(rq
);
7697 on_rq
= p
->se
.on_rq
;
7699 deactivate_task(rq
, p
, 0);
7700 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7702 activate_task(rq
, p
, 0);
7703 resched_task(rq
->curr
);
7707 void normalize_rt_tasks(void)
7709 struct task_struct
*g
, *p
;
7710 unsigned long flags
;
7713 read_lock_irqsave(&tasklist_lock
, flags
);
7714 do_each_thread(g
, p
) {
7716 * Only normalize user tasks:
7721 p
->se
.exec_start
= 0;
7722 #ifdef CONFIG_SCHEDSTATS
7723 p
->se
.wait_start
= 0;
7724 p
->se
.sleep_start
= 0;
7725 p
->se
.block_start
= 0;
7727 task_rq(p
)->clock
= 0;
7731 * Renice negative nice level userspace
7734 if (TASK_NICE(p
) < 0 && p
->mm
)
7735 set_user_nice(p
, 0);
7739 spin_lock(&p
->pi_lock
);
7740 rq
= __task_rq_lock(p
);
7742 normalize_task(rq
, p
);
7744 __task_rq_unlock(rq
);
7745 spin_unlock(&p
->pi_lock
);
7746 } while_each_thread(g
, p
);
7748 read_unlock_irqrestore(&tasklist_lock
, flags
);
7751 #endif /* CONFIG_MAGIC_SYSRQ */
7755 * These functions are only useful for the IA64 MCA handling.
7757 * They can only be called when the whole system has been
7758 * stopped - every CPU needs to be quiescent, and no scheduling
7759 * activity can take place. Using them for anything else would
7760 * be a serious bug, and as a result, they aren't even visible
7761 * under any other configuration.
7765 * curr_task - return the current task for a given cpu.
7766 * @cpu: the processor in question.
7768 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7770 struct task_struct
*curr_task(int cpu
)
7772 return cpu_curr(cpu
);
7776 * set_curr_task - set the current task for a given cpu.
7777 * @cpu: the processor in question.
7778 * @p: the task pointer to set.
7780 * Description: This function must only be used when non-maskable interrupts
7781 * are serviced on a separate stack. It allows the architecture to switch the
7782 * notion of the current task on a cpu in a non-blocking manner. This function
7783 * must be called with all CPU's synchronized, and interrupts disabled, the
7784 * and caller must save the original value of the current task (see
7785 * curr_task() above) and restore that value before reenabling interrupts and
7786 * re-starting the system.
7788 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7790 void set_curr_task(int cpu
, struct task_struct
*p
)
7797 #ifdef CONFIG_FAIR_GROUP_SCHED
7798 static void free_fair_sched_group(struct task_group
*tg
)
7802 for_each_possible_cpu(i
) {
7804 kfree(tg
->cfs_rq
[i
]);
7814 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7816 struct cfs_rq
*cfs_rq
;
7817 struct sched_entity
*se
, *parent_se
;
7821 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
7824 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
7828 tg
->shares
= NICE_0_LOAD
;
7830 for_each_possible_cpu(i
) {
7833 cfs_rq
= kmalloc_node(sizeof(struct cfs_rq
),
7834 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7838 se
= kmalloc_node(sizeof(struct sched_entity
),
7839 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7843 parent_se
= parent
? parent
->se
[i
] : NULL
;
7844 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent_se
);
7853 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7855 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
7856 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
7859 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
7861 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
7864 static inline void free_fair_sched_group(struct task_group
*tg
)
7869 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7874 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7878 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
7883 #ifdef CONFIG_RT_GROUP_SCHED
7884 static void free_rt_sched_group(struct task_group
*tg
)
7888 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
7890 for_each_possible_cpu(i
) {
7892 kfree(tg
->rt_rq
[i
]);
7894 kfree(tg
->rt_se
[i
]);
7902 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7904 struct rt_rq
*rt_rq
;
7905 struct sched_rt_entity
*rt_se
, *parent_se
;
7909 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
7912 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
7916 init_rt_bandwidth(&tg
->rt_bandwidth
,
7917 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
7919 for_each_possible_cpu(i
) {
7922 rt_rq
= kmalloc_node(sizeof(struct rt_rq
),
7923 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7927 rt_se
= kmalloc_node(sizeof(struct sched_rt_entity
),
7928 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7932 parent_se
= parent
? parent
->rt_se
[i
] : NULL
;
7933 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent_se
);
7942 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
7944 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
7945 &cpu_rq(cpu
)->leaf_rt_rq_list
);
7948 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
7950 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
7953 static inline void free_rt_sched_group(struct task_group
*tg
)
7958 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7963 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
7967 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
7972 #ifdef CONFIG_GROUP_SCHED
7973 static void free_sched_group(struct task_group
*tg
)
7975 free_fair_sched_group(tg
);
7976 free_rt_sched_group(tg
);
7980 /* allocate runqueue etc for a new task group */
7981 struct task_group
*sched_create_group(struct task_group
*parent
)
7983 struct task_group
*tg
;
7984 unsigned long flags
;
7987 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7989 return ERR_PTR(-ENOMEM
);
7991 if (!alloc_fair_sched_group(tg
, parent
))
7994 if (!alloc_rt_sched_group(tg
, parent
))
7997 spin_lock_irqsave(&task_group_lock
, flags
);
7998 for_each_possible_cpu(i
) {
7999 register_fair_sched_group(tg
, i
);
8000 register_rt_sched_group(tg
, i
);
8002 list_add_rcu(&tg
->list
, &task_groups
);
8003 spin_unlock_irqrestore(&task_group_lock
, flags
);
8008 free_sched_group(tg
);
8009 return ERR_PTR(-ENOMEM
);
8012 /* rcu callback to free various structures associated with a task group */
8013 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8015 /* now it should be safe to free those cfs_rqs */
8016 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8019 /* Destroy runqueue etc associated with a task group */
8020 void sched_destroy_group(struct task_group
*tg
)
8022 unsigned long flags
;
8025 spin_lock_irqsave(&task_group_lock
, flags
);
8026 for_each_possible_cpu(i
) {
8027 unregister_fair_sched_group(tg
, i
);
8028 unregister_rt_sched_group(tg
, i
);
8030 list_del_rcu(&tg
->list
);
8031 spin_unlock_irqrestore(&task_group_lock
, flags
);
8033 /* wait for possible concurrent references to cfs_rqs complete */
8034 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8037 /* change task's runqueue when it moves between groups.
8038 * The caller of this function should have put the task in its new group
8039 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8040 * reflect its new group.
8042 void sched_move_task(struct task_struct
*tsk
)
8045 unsigned long flags
;
8048 rq
= task_rq_lock(tsk
, &flags
);
8050 update_rq_clock(rq
);
8052 running
= task_current(rq
, tsk
);
8053 on_rq
= tsk
->se
.on_rq
;
8056 dequeue_task(rq
, tsk
, 0);
8057 if (unlikely(running
))
8058 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8060 set_task_rq(tsk
, task_cpu(tsk
));
8062 #ifdef CONFIG_FAIR_GROUP_SCHED
8063 if (tsk
->sched_class
->moved_group
)
8064 tsk
->sched_class
->moved_group(tsk
);
8067 if (unlikely(running
))
8068 tsk
->sched_class
->set_curr_task(rq
);
8070 enqueue_task(rq
, tsk
, 0);
8072 task_rq_unlock(rq
, &flags
);
8076 #ifdef CONFIG_FAIR_GROUP_SCHED
8077 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8079 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8080 struct rq
*rq
= cfs_rq
->rq
;
8083 spin_lock_irq(&rq
->lock
);
8087 dequeue_entity(cfs_rq
, se
, 0);
8089 se
->load
.weight
= shares
;
8090 se
->load
.inv_weight
= div64_64((1ULL<<32), shares
);
8093 enqueue_entity(cfs_rq
, se
, 0);
8095 spin_unlock_irq(&rq
->lock
);
8098 static DEFINE_MUTEX(shares_mutex
);
8100 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8103 unsigned long flags
;
8106 * We can't change the weight of the root cgroup.
8112 * A weight of 0 or 1 can cause arithmetics problems.
8113 * (The default weight is 1024 - so there's no practical
8114 * limitation from this.)
8119 mutex_lock(&shares_mutex
);
8120 if (tg
->shares
== shares
)
8123 spin_lock_irqsave(&task_group_lock
, flags
);
8124 for_each_possible_cpu(i
)
8125 unregister_fair_sched_group(tg
, i
);
8126 spin_unlock_irqrestore(&task_group_lock
, flags
);
8128 /* wait for any ongoing reference to this group to finish */
8129 synchronize_sched();
8132 * Now we are free to modify the group's share on each cpu
8133 * w/o tripping rebalance_share or load_balance_fair.
8135 tg
->shares
= shares
;
8136 for_each_possible_cpu(i
)
8137 set_se_shares(tg
->se
[i
], shares
);
8140 * Enable load balance activity on this group, by inserting it back on
8141 * each cpu's rq->leaf_cfs_rq_list.
8143 spin_lock_irqsave(&task_group_lock
, flags
);
8144 for_each_possible_cpu(i
)
8145 register_fair_sched_group(tg
, i
);
8146 spin_unlock_irqrestore(&task_group_lock
, flags
);
8148 mutex_unlock(&shares_mutex
);
8152 unsigned long sched_group_shares(struct task_group
*tg
)
8158 #ifdef CONFIG_RT_GROUP_SCHED
8160 * Ensure that the real time constraints are schedulable.
8162 static DEFINE_MUTEX(rt_constraints_mutex
);
8164 static unsigned long to_ratio(u64 period
, u64 runtime
)
8166 if (runtime
== RUNTIME_INF
)
8169 return div64_64(runtime
<< 16, period
);
8172 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8174 struct task_group
*tgi
;
8175 unsigned long total
= 0;
8176 unsigned long global_ratio
=
8177 to_ratio(global_rt_period(), global_rt_runtime());
8180 list_for_each_entry_rcu(tgi
, &task_groups
, list
) {
8184 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8185 tgi
->rt_bandwidth
.rt_runtime
);
8189 return total
+ to_ratio(period
, runtime
) < global_ratio
;
8192 /* Must be called with tasklist_lock held */
8193 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8195 struct task_struct
*g
, *p
;
8196 do_each_thread(g
, p
) {
8197 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8199 } while_each_thread(g
, p
);
8203 static int tg_set_bandwidth(struct task_group
*tg
,
8204 u64 rt_period
, u64 rt_runtime
)
8208 mutex_lock(&rt_constraints_mutex
);
8209 read_lock(&tasklist_lock
);
8210 if (rt_runtime
== 0 && tg_has_rt_tasks(tg
)) {
8214 if (!__rt_schedulable(tg
, rt_period
, rt_runtime
)) {
8219 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8220 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8221 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8223 for_each_possible_cpu(i
) {
8224 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8226 spin_lock(&rt_rq
->rt_runtime_lock
);
8227 rt_rq
->rt_runtime
= rt_runtime
;
8228 spin_unlock(&rt_rq
->rt_runtime_lock
);
8230 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8232 read_unlock(&tasklist_lock
);
8233 mutex_unlock(&rt_constraints_mutex
);
8238 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8240 u64 rt_runtime
, rt_period
;
8242 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8243 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8244 if (rt_runtime_us
< 0)
8245 rt_runtime
= RUNTIME_INF
;
8247 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8250 long sched_group_rt_runtime(struct task_group
*tg
)
8254 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8257 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8258 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8259 return rt_runtime_us
;
8262 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8264 u64 rt_runtime
, rt_period
;
8266 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8267 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8269 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8272 long sched_group_rt_period(struct task_group
*tg
)
8276 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8277 do_div(rt_period_us
, NSEC_PER_USEC
);
8278 return rt_period_us
;
8281 static int sched_rt_global_constraints(void)
8285 mutex_lock(&rt_constraints_mutex
);
8286 if (!__rt_schedulable(NULL
, 1, 0))
8288 mutex_unlock(&rt_constraints_mutex
);
8293 static int sched_rt_global_constraints(void)
8295 unsigned long flags
;
8298 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8299 for_each_possible_cpu(i
) {
8300 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8302 spin_lock(&rt_rq
->rt_runtime_lock
);
8303 rt_rq
->rt_runtime
= global_rt_runtime();
8304 spin_unlock(&rt_rq
->rt_runtime_lock
);
8306 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8312 int sched_rt_handler(struct ctl_table
*table
, int write
,
8313 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
8317 int old_period
, old_runtime
;
8318 static DEFINE_MUTEX(mutex
);
8321 old_period
= sysctl_sched_rt_period
;
8322 old_runtime
= sysctl_sched_rt_runtime
;
8324 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
8326 if (!ret
&& write
) {
8327 ret
= sched_rt_global_constraints();
8329 sysctl_sched_rt_period
= old_period
;
8330 sysctl_sched_rt_runtime
= old_runtime
;
8332 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8333 def_rt_bandwidth
.rt_period
=
8334 ns_to_ktime(global_rt_period());
8337 mutex_unlock(&mutex
);
8342 #ifdef CONFIG_CGROUP_SCHED
8344 /* return corresponding task_group object of a cgroup */
8345 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8347 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8348 struct task_group
, css
);
8351 static struct cgroup_subsys_state
*
8352 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8354 struct task_group
*tg
, *parent
;
8356 if (!cgrp
->parent
) {
8357 /* This is early initialization for the top cgroup */
8358 init_task_group
.css
.cgroup
= cgrp
;
8359 return &init_task_group
.css
;
8362 parent
= cgroup_tg(cgrp
->parent
);
8363 tg
= sched_create_group(parent
);
8365 return ERR_PTR(-ENOMEM
);
8367 /* Bind the cgroup to task_group object we just created */
8368 tg
->css
.cgroup
= cgrp
;
8374 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8376 struct task_group
*tg
= cgroup_tg(cgrp
);
8378 sched_destroy_group(tg
);
8382 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8383 struct task_struct
*tsk
)
8385 #ifdef CONFIG_RT_GROUP_SCHED
8386 /* Don't accept realtime tasks when there is no way for them to run */
8387 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
8390 /* We don't support RT-tasks being in separate groups */
8391 if (tsk
->sched_class
!= &fair_sched_class
)
8399 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8400 struct cgroup
*old_cont
, struct task_struct
*tsk
)
8402 sched_move_task(tsk
);
8405 #ifdef CONFIG_FAIR_GROUP_SCHED
8406 static int cpu_shares_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8409 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8412 static u64
cpu_shares_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8414 struct task_group
*tg
= cgroup_tg(cgrp
);
8416 return (u64
) tg
->shares
;
8420 #ifdef CONFIG_RT_GROUP_SCHED
8421 static ssize_t
cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8423 const char __user
*userbuf
,
8424 size_t nbytes
, loff_t
*unused_ppos
)
8433 if (nbytes
>= sizeof(buffer
))
8435 if (copy_from_user(buffer
, userbuf
, nbytes
))
8438 buffer
[nbytes
] = 0; /* nul-terminate */
8440 /* strip newline if necessary */
8441 if (nbytes
&& (buffer
[nbytes
-1] == '\n'))
8442 buffer
[nbytes
-1] = 0;
8443 val
= simple_strtoll(buffer
, &end
, 0);
8447 /* Pass to subsystem */
8448 retval
= sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8454 static ssize_t
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
,
8456 char __user
*buf
, size_t nbytes
,
8460 long val
= sched_group_rt_runtime(cgroup_tg(cgrp
));
8461 int len
= sprintf(tmp
, "%ld\n", val
);
8463 return simple_read_from_buffer(buf
, nbytes
, ppos
, tmp
, len
);
8466 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8469 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8472 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8474 return sched_group_rt_period(cgroup_tg(cgrp
));
8478 static struct cftype cpu_files
[] = {
8479 #ifdef CONFIG_FAIR_GROUP_SCHED
8482 .read_uint
= cpu_shares_read_uint
,
8483 .write_uint
= cpu_shares_write_uint
,
8486 #ifdef CONFIG_RT_GROUP_SCHED
8488 .name
= "rt_runtime_us",
8489 .read
= cpu_rt_runtime_read
,
8490 .write
= cpu_rt_runtime_write
,
8493 .name
= "rt_period_us",
8494 .read_uint
= cpu_rt_period_read_uint
,
8495 .write_uint
= cpu_rt_period_write_uint
,
8500 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8502 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8505 struct cgroup_subsys cpu_cgroup_subsys
= {
8507 .create
= cpu_cgroup_create
,
8508 .destroy
= cpu_cgroup_destroy
,
8509 .can_attach
= cpu_cgroup_can_attach
,
8510 .attach
= cpu_cgroup_attach
,
8511 .populate
= cpu_cgroup_populate
,
8512 .subsys_id
= cpu_cgroup_subsys_id
,
8516 #endif /* CONFIG_CGROUP_SCHED */
8518 #ifdef CONFIG_CGROUP_CPUACCT
8521 * CPU accounting code for task groups.
8523 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8524 * (balbir@in.ibm.com).
8527 /* track cpu usage of a group of tasks */
8529 struct cgroup_subsys_state css
;
8530 /* cpuusage holds pointer to a u64-type object on every cpu */
8534 struct cgroup_subsys cpuacct_subsys
;
8536 /* return cpu accounting group corresponding to this container */
8537 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8539 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8540 struct cpuacct
, css
);
8543 /* return cpu accounting group to which this task belongs */
8544 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8546 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8547 struct cpuacct
, css
);
8550 /* create a new cpu accounting group */
8551 static struct cgroup_subsys_state
*cpuacct_create(
8552 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8554 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8557 return ERR_PTR(-ENOMEM
);
8559 ca
->cpuusage
= alloc_percpu(u64
);
8560 if (!ca
->cpuusage
) {
8562 return ERR_PTR(-ENOMEM
);
8568 /* destroy an existing cpu accounting group */
8570 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8572 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8574 free_percpu(ca
->cpuusage
);
8578 /* return total cpu usage (in nanoseconds) of a group */
8579 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8581 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8582 u64 totalcpuusage
= 0;
8585 for_each_possible_cpu(i
) {
8586 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8589 * Take rq->lock to make 64-bit addition safe on 32-bit
8592 spin_lock_irq(&cpu_rq(i
)->lock
);
8593 totalcpuusage
+= *cpuusage
;
8594 spin_unlock_irq(&cpu_rq(i
)->lock
);
8597 return totalcpuusage
;
8600 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8603 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8612 for_each_possible_cpu(i
) {
8613 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8615 spin_lock_irq(&cpu_rq(i
)->lock
);
8617 spin_unlock_irq(&cpu_rq(i
)->lock
);
8623 static struct cftype files
[] = {
8626 .read_uint
= cpuusage_read
,
8627 .write_uint
= cpuusage_write
,
8631 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8633 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8637 * charge this task's execution time to its accounting group.
8639 * called with rq->lock held.
8641 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8645 if (!cpuacct_subsys
.active
)
8650 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, task_cpu(tsk
));
8652 *cpuusage
+= cputime
;
8656 struct cgroup_subsys cpuacct_subsys
= {
8658 .create
= cpuacct_create
,
8659 .destroy
= cpuacct_destroy
,
8660 .populate
= cpuacct_populate
,
8661 .subsys_id
= cpuacct_subsys_id
,
8663 #endif /* CONFIG_CGROUP_CPUACCT */