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
{
168 spinlock_t rt_runtime_lock
;
169 struct hrtimer rt_period_timer
;
172 static struct rt_bandwidth def_rt_bandwidth
;
174 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
176 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
178 struct rt_bandwidth
*rt_b
=
179 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
185 now
= hrtimer_cb_get_time(timer
);
186 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
191 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
194 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
198 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
200 rt_b
->rt_period
= ns_to_ktime(period
);
201 rt_b
->rt_runtime
= runtime
;
203 spin_lock_init(&rt_b
->rt_runtime_lock
);
205 hrtimer_init(&rt_b
->rt_period_timer
,
206 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
207 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
208 rt_b
->rt_period_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
211 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
215 if (rt_b
->rt_runtime
== RUNTIME_INF
)
218 if (hrtimer_active(&rt_b
->rt_period_timer
))
221 spin_lock(&rt_b
->rt_runtime_lock
);
223 if (hrtimer_active(&rt_b
->rt_period_timer
))
226 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
227 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
228 hrtimer_start(&rt_b
->rt_period_timer
,
229 rt_b
->rt_period_timer
.expires
,
232 spin_unlock(&rt_b
->rt_runtime_lock
);
235 #ifdef CONFIG_RT_GROUP_SCHED
236 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
238 hrtimer_cancel(&rt_b
->rt_period_timer
);
242 #ifdef CONFIG_GROUP_SCHED
244 #include <linux/cgroup.h>
248 static LIST_HEAD(task_groups
);
250 /* task group related information */
252 #ifdef CONFIG_CGROUP_SCHED
253 struct cgroup_subsys_state css
;
256 #ifdef CONFIG_FAIR_GROUP_SCHED
257 /* schedulable entities of this group on each cpu */
258 struct sched_entity
**se
;
259 /* runqueue "owned" by this group on each cpu */
260 struct cfs_rq
**cfs_rq
;
261 unsigned long shares
;
264 #ifdef CONFIG_RT_GROUP_SCHED
265 struct sched_rt_entity
**rt_se
;
266 struct rt_rq
**rt_rq
;
268 struct rt_bandwidth rt_bandwidth
;
272 struct list_head list
;
275 #ifdef CONFIG_FAIR_GROUP_SCHED
276 /* Default task group's sched entity on each cpu */
277 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
278 /* Default task group's cfs_rq on each cpu */
279 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
282 #ifdef CONFIG_RT_GROUP_SCHED
283 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
284 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
287 /* task_group_lock serializes add/remove of task groups and also changes to
288 * a task group's cpu shares.
290 static DEFINE_SPINLOCK(task_group_lock
);
292 /* doms_cur_mutex serializes access to doms_cur[] array */
293 static DEFINE_MUTEX(doms_cur_mutex
);
295 #ifdef CONFIG_FAIR_GROUP_SCHED
296 #ifdef CONFIG_USER_SCHED
297 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
299 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
302 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
305 /* Default task group.
306 * Every task in system belong to this group at bootup.
308 struct task_group init_task_group
;
310 /* return group to which a task belongs */
311 static inline struct task_group
*task_group(struct task_struct
*p
)
313 struct task_group
*tg
;
315 #ifdef CONFIG_USER_SCHED
317 #elif defined(CONFIG_CGROUP_SCHED)
318 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
319 struct task_group
, css
);
321 tg
= &init_task_group
;
326 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
327 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
329 #ifdef CONFIG_FAIR_GROUP_SCHED
330 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
331 p
->se
.parent
= task_group(p
)->se
[cpu
];
334 #ifdef CONFIG_RT_GROUP_SCHED
335 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
336 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
340 static inline void lock_doms_cur(void)
342 mutex_lock(&doms_cur_mutex
);
345 static inline void unlock_doms_cur(void)
347 mutex_unlock(&doms_cur_mutex
);
352 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
353 static inline void lock_doms_cur(void) { }
354 static inline void unlock_doms_cur(void) { }
356 #endif /* CONFIG_GROUP_SCHED */
358 /* CFS-related fields in a runqueue */
360 struct load_weight load
;
361 unsigned long nr_running
;
366 struct rb_root tasks_timeline
;
367 struct rb_node
*rb_leftmost
;
368 struct rb_node
*rb_load_balance_curr
;
369 /* 'curr' points to currently running entity on this cfs_rq.
370 * It is set to NULL otherwise (i.e when none are currently running).
372 struct sched_entity
*curr
, *next
;
374 unsigned long nr_spread_over
;
376 #ifdef CONFIG_FAIR_GROUP_SCHED
377 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
380 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
381 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
382 * (like users, containers etc.)
384 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
385 * list is used during load balance.
387 struct list_head leaf_cfs_rq_list
;
388 struct task_group
*tg
; /* group that "owns" this runqueue */
392 /* Real-Time classes' related field in a runqueue: */
394 struct rt_prio_array active
;
395 unsigned long rt_nr_running
;
396 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
397 int highest_prio
; /* highest queued rt task prio */
400 unsigned long rt_nr_migratory
;
406 spinlock_t rt_runtime_lock
;
408 #ifdef CONFIG_RT_GROUP_SCHED
409 unsigned long rt_nr_boosted
;
412 struct list_head leaf_rt_rq_list
;
413 struct task_group
*tg
;
414 struct sched_rt_entity
*rt_se
;
421 * We add the notion of a root-domain which will be used to define per-domain
422 * variables. Each exclusive cpuset essentially defines an island domain by
423 * fully partitioning the member cpus from any other cpuset. Whenever a new
424 * exclusive cpuset is created, we also create and attach a new root-domain
434 * The "RT overload" flag: it gets set if a CPU has more than
435 * one runnable RT task.
442 * By default the system creates a single root-domain with all cpus as
443 * members (mimicking the global state we have today).
445 static struct root_domain def_root_domain
;
450 * This is the main, per-CPU runqueue data structure.
452 * Locking rule: those places that want to lock multiple runqueues
453 * (such as the load balancing or the thread migration code), lock
454 * acquire operations must be ordered by ascending &runqueue.
461 * nr_running and cpu_load should be in the same cacheline because
462 * remote CPUs use both these fields when doing load calculation.
464 unsigned long nr_running
;
465 #define CPU_LOAD_IDX_MAX 5
466 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
467 unsigned char idle_at_tick
;
469 unsigned long last_tick_seen
;
470 unsigned char in_nohz_recently
;
472 /* capture load from *all* tasks on this cpu: */
473 struct load_weight load
;
474 unsigned long nr_load_updates
;
480 #ifdef CONFIG_FAIR_GROUP_SCHED
481 /* list of leaf cfs_rq on this cpu: */
482 struct list_head leaf_cfs_rq_list
;
484 #ifdef CONFIG_RT_GROUP_SCHED
485 struct list_head leaf_rt_rq_list
;
489 * This is part of a global counter where only the total sum
490 * over all CPUs matters. A task can increase this counter on
491 * one CPU and if it got migrated afterwards it may decrease
492 * it on another CPU. Always updated under the runqueue lock:
494 unsigned long nr_uninterruptible
;
496 struct task_struct
*curr
, *idle
;
497 unsigned long next_balance
;
498 struct mm_struct
*prev_mm
;
500 u64 clock
, prev_clock_raw
;
503 unsigned int clock_warps
, clock_overflows
, clock_underflows
;
505 unsigned int clock_deep_idle_events
;
511 struct root_domain
*rd
;
512 struct sched_domain
*sd
;
514 /* For active balancing */
517 /* cpu of this runqueue: */
520 struct task_struct
*migration_thread
;
521 struct list_head migration_queue
;
524 #ifdef CONFIG_SCHED_HRTICK
525 unsigned long hrtick_flags
;
526 ktime_t hrtick_expire
;
527 struct hrtimer hrtick_timer
;
530 #ifdef CONFIG_SCHEDSTATS
532 struct sched_info rq_sched_info
;
534 /* sys_sched_yield() stats */
535 unsigned int yld_exp_empty
;
536 unsigned int yld_act_empty
;
537 unsigned int yld_both_empty
;
538 unsigned int yld_count
;
540 /* schedule() stats */
541 unsigned int sched_switch
;
542 unsigned int sched_count
;
543 unsigned int sched_goidle
;
545 /* try_to_wake_up() stats */
546 unsigned int ttwu_count
;
547 unsigned int ttwu_local
;
550 unsigned int bkl_count
;
552 struct lock_class_key rq_lock_key
;
555 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
557 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
)
559 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
);
562 static inline int cpu_of(struct rq
*rq
)
572 static inline bool nohz_on(int cpu
)
574 return tick_get_tick_sched(cpu
)->nohz_mode
!= NOHZ_MODE_INACTIVE
;
577 static inline u64
max_skipped_ticks(struct rq
*rq
)
579 return nohz_on(cpu_of(rq
)) ? jiffies
- rq
->last_tick_seen
+ 2 : 1;
582 static inline void update_last_tick_seen(struct rq
*rq
)
584 rq
->last_tick_seen
= jiffies
;
587 static inline u64
max_skipped_ticks(struct rq
*rq
)
592 static inline void update_last_tick_seen(struct rq
*rq
)
598 * Update the per-runqueue clock, as finegrained as the platform can give
599 * us, but without assuming monotonicity, etc.:
601 static void __update_rq_clock(struct rq
*rq
)
603 u64 prev_raw
= rq
->prev_clock_raw
;
604 u64 now
= sched_clock();
605 s64 delta
= now
- prev_raw
;
606 u64 clock
= rq
->clock
;
608 #ifdef CONFIG_SCHED_DEBUG
609 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
612 * Protect against sched_clock() occasionally going backwards:
614 if (unlikely(delta
< 0)) {
619 * Catch too large forward jumps too:
621 u64 max_jump
= max_skipped_ticks(rq
) * TICK_NSEC
;
622 u64 max_time
= rq
->tick_timestamp
+ max_jump
;
624 if (unlikely(clock
+ delta
> max_time
)) {
625 if (clock
< max_time
)
629 rq
->clock_overflows
++;
631 if (unlikely(delta
> rq
->clock_max_delta
))
632 rq
->clock_max_delta
= delta
;
637 rq
->prev_clock_raw
= now
;
641 static void update_rq_clock(struct rq
*rq
)
643 if (likely(smp_processor_id() == cpu_of(rq
)))
644 __update_rq_clock(rq
);
648 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
649 * See detach_destroy_domains: synchronize_sched for details.
651 * The domain tree of any CPU may only be accessed from within
652 * preempt-disabled sections.
654 #define for_each_domain(cpu, __sd) \
655 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
657 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
658 #define this_rq() (&__get_cpu_var(runqueues))
659 #define task_rq(p) cpu_rq(task_cpu(p))
660 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
663 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
665 #ifdef CONFIG_SCHED_DEBUG
666 # define const_debug __read_mostly
668 # define const_debug static const
672 * Debugging: various feature bits
675 SCHED_FEAT_NEW_FAIR_SLEEPERS
= 1,
676 SCHED_FEAT_WAKEUP_PREEMPT
= 2,
677 SCHED_FEAT_START_DEBIT
= 4,
678 SCHED_FEAT_AFFINE_WAKEUPS
= 8,
679 SCHED_FEAT_CACHE_HOT_BUDDY
= 16,
680 SCHED_FEAT_SYNC_WAKEUPS
= 32,
681 SCHED_FEAT_HRTICK
= 64,
682 SCHED_FEAT_DOUBLE_TICK
= 128,
685 const_debug
unsigned int sysctl_sched_features
=
686 SCHED_FEAT_NEW_FAIR_SLEEPERS
* 1 |
687 SCHED_FEAT_WAKEUP_PREEMPT
* 1 |
688 SCHED_FEAT_START_DEBIT
* 1 |
689 SCHED_FEAT_AFFINE_WAKEUPS
* 1 |
690 SCHED_FEAT_CACHE_HOT_BUDDY
* 1 |
691 SCHED_FEAT_SYNC_WAKEUPS
* 1 |
692 SCHED_FEAT_HRTICK
* 1 |
693 SCHED_FEAT_DOUBLE_TICK
* 0;
695 #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
698 * Number of tasks to iterate in a single balance run.
699 * Limited because this is done with IRQs disabled.
701 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
704 * period over which we measure -rt task cpu usage in us.
707 unsigned int sysctl_sched_rt_period
= 1000000;
709 static __read_mostly
int scheduler_running
;
712 * part of the period that we allow rt tasks to run in us.
715 int sysctl_sched_rt_runtime
= 950000;
717 static inline u64
global_rt_period(void)
719 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
722 static inline u64
global_rt_runtime(void)
724 if (sysctl_sched_rt_period
< 0)
727 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
730 static const unsigned long long time_sync_thresh
= 100000;
732 static DEFINE_PER_CPU(unsigned long long, time_offset
);
733 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time
);
736 * Global lock which we take every now and then to synchronize
737 * the CPUs time. This method is not warp-safe, but it's good
738 * enough to synchronize slowly diverging time sources and thus
739 * it's good enough for tracing:
741 static DEFINE_SPINLOCK(time_sync_lock
);
742 static unsigned long long prev_global_time
;
744 static unsigned long long __sync_cpu_clock(cycles_t time
, int cpu
)
748 spin_lock_irqsave(&time_sync_lock
, flags
);
750 if (time
< prev_global_time
) {
751 per_cpu(time_offset
, cpu
) += prev_global_time
- time
;
752 time
= prev_global_time
;
754 prev_global_time
= time
;
757 spin_unlock_irqrestore(&time_sync_lock
, flags
);
762 static unsigned long long __cpu_clock(int cpu
)
764 unsigned long long now
;
769 * Only call sched_clock() if the scheduler has already been
770 * initialized (some code might call cpu_clock() very early):
772 if (unlikely(!scheduler_running
))
775 local_irq_save(flags
);
779 local_irq_restore(flags
);
785 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
786 * clock constructed from sched_clock():
788 unsigned long long cpu_clock(int cpu
)
790 unsigned long long prev_cpu_time
, time
, delta_time
;
792 prev_cpu_time
= per_cpu(prev_cpu_time
, cpu
);
793 time
= __cpu_clock(cpu
) + per_cpu(time_offset
, cpu
);
794 delta_time
= time
-prev_cpu_time
;
796 if (unlikely(delta_time
> time_sync_thresh
))
797 time
= __sync_cpu_clock(time
, cpu
);
801 EXPORT_SYMBOL_GPL(cpu_clock
);
803 #ifndef prepare_arch_switch
804 # define prepare_arch_switch(next) do { } while (0)
806 #ifndef finish_arch_switch
807 # define finish_arch_switch(prev) do { } while (0)
810 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
812 return rq
->curr
== p
;
815 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
816 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
818 return task_current(rq
, p
);
821 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
825 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
827 #ifdef CONFIG_DEBUG_SPINLOCK
828 /* this is a valid case when another task releases the spinlock */
829 rq
->lock
.owner
= current
;
832 * If we are tracking spinlock dependencies then we have to
833 * fix up the runqueue lock - which gets 'carried over' from
836 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
838 spin_unlock_irq(&rq
->lock
);
841 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
842 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
847 return task_current(rq
, p
);
851 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
855 * We can optimise this out completely for !SMP, because the
856 * SMP rebalancing from interrupt is the only thing that cares
861 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
862 spin_unlock_irq(&rq
->lock
);
864 spin_unlock(&rq
->lock
);
868 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
872 * After ->oncpu is cleared, the task can be moved to a different CPU.
873 * We must ensure this doesn't happen until the switch is completely
879 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
883 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
886 * __task_rq_lock - lock the runqueue a given task resides on.
887 * Must be called interrupts disabled.
889 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
893 struct rq
*rq
= task_rq(p
);
894 spin_lock(&rq
->lock
);
895 if (likely(rq
== task_rq(p
)))
897 spin_unlock(&rq
->lock
);
902 * task_rq_lock - lock the runqueue a given task resides on and disable
903 * interrupts. Note the ordering: we can safely lookup the task_rq without
904 * explicitly disabling preemption.
906 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
912 local_irq_save(*flags
);
914 spin_lock(&rq
->lock
);
915 if (likely(rq
== task_rq(p
)))
917 spin_unlock_irqrestore(&rq
->lock
, *flags
);
921 static void __task_rq_unlock(struct rq
*rq
)
924 spin_unlock(&rq
->lock
);
927 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
930 spin_unlock_irqrestore(&rq
->lock
, *flags
);
934 * this_rq_lock - lock this runqueue and disable interrupts.
936 static struct rq
*this_rq_lock(void)
943 spin_lock(&rq
->lock
);
949 * We are going deep-idle (irqs are disabled):
951 void sched_clock_idle_sleep_event(void)
953 struct rq
*rq
= cpu_rq(smp_processor_id());
955 spin_lock(&rq
->lock
);
956 __update_rq_clock(rq
);
957 spin_unlock(&rq
->lock
);
958 rq
->clock_deep_idle_events
++;
960 EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event
);
963 * We just idled delta nanoseconds (called with irqs disabled):
965 void sched_clock_idle_wakeup_event(u64 delta_ns
)
967 struct rq
*rq
= cpu_rq(smp_processor_id());
968 u64 now
= sched_clock();
970 rq
->idle_clock
+= delta_ns
;
972 * Override the previous timestamp and ignore all
973 * sched_clock() deltas that occured while we idled,
974 * and use the PM-provided delta_ns to advance the
977 spin_lock(&rq
->lock
);
978 rq
->prev_clock_raw
= now
;
979 rq
->clock
+= delta_ns
;
980 spin_unlock(&rq
->lock
);
981 touch_softlockup_watchdog();
983 EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event
);
985 static void __resched_task(struct task_struct
*p
, int tif_bit
);
987 static inline void resched_task(struct task_struct
*p
)
989 __resched_task(p
, TIF_NEED_RESCHED
);
992 #ifdef CONFIG_SCHED_HRTICK
994 * Use HR-timers to deliver accurate preemption points.
996 * Its all a bit involved since we cannot program an hrt while holding the
997 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1000 * When we get rescheduled we reprogram the hrtick_timer outside of the
1003 static inline void resched_hrt(struct task_struct
*p
)
1005 __resched_task(p
, TIF_HRTICK_RESCHED
);
1008 static inline void resched_rq(struct rq
*rq
)
1010 unsigned long flags
;
1012 spin_lock_irqsave(&rq
->lock
, flags
);
1013 resched_task(rq
->curr
);
1014 spin_unlock_irqrestore(&rq
->lock
, flags
);
1018 HRTICK_SET
, /* re-programm hrtick_timer */
1019 HRTICK_RESET
, /* not a new slice */
1024 * - enabled by features
1025 * - hrtimer is actually high res
1027 static inline int hrtick_enabled(struct rq
*rq
)
1029 if (!sched_feat(HRTICK
))
1031 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1035 * Called to set the hrtick timer state.
1037 * called with rq->lock held and irqs disabled
1039 static void hrtick_start(struct rq
*rq
, u64 delay
, int reset
)
1041 assert_spin_locked(&rq
->lock
);
1044 * preempt at: now + delay
1047 ktime_add_ns(rq
->hrtick_timer
.base
->get_time(), delay
);
1049 * indicate we need to program the timer
1051 __set_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1053 __set_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1056 * New slices are called from the schedule path and don't need a
1057 * forced reschedule.
1060 resched_hrt(rq
->curr
);
1063 static void hrtick_clear(struct rq
*rq
)
1065 if (hrtimer_active(&rq
->hrtick_timer
))
1066 hrtimer_cancel(&rq
->hrtick_timer
);
1070 * Update the timer from the possible pending state.
1072 static void hrtick_set(struct rq
*rq
)
1076 unsigned long flags
;
1078 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1080 spin_lock_irqsave(&rq
->lock
, flags
);
1081 set
= __test_and_clear_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1082 reset
= __test_and_clear_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1083 time
= rq
->hrtick_expire
;
1084 clear_thread_flag(TIF_HRTICK_RESCHED
);
1085 spin_unlock_irqrestore(&rq
->lock
, flags
);
1088 hrtimer_start(&rq
->hrtick_timer
, time
, HRTIMER_MODE_ABS
);
1089 if (reset
&& !hrtimer_active(&rq
->hrtick_timer
))
1096 * High-resolution timer tick.
1097 * Runs from hardirq context with interrupts disabled.
1099 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1101 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1103 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1105 spin_lock(&rq
->lock
);
1106 __update_rq_clock(rq
);
1107 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1108 spin_unlock(&rq
->lock
);
1110 return HRTIMER_NORESTART
;
1113 static inline void init_rq_hrtick(struct rq
*rq
)
1115 rq
->hrtick_flags
= 0;
1116 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1117 rq
->hrtick_timer
.function
= hrtick
;
1118 rq
->hrtick_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1121 void hrtick_resched(void)
1124 unsigned long flags
;
1126 if (!test_thread_flag(TIF_HRTICK_RESCHED
))
1129 local_irq_save(flags
);
1130 rq
= cpu_rq(smp_processor_id());
1132 local_irq_restore(flags
);
1135 static inline void hrtick_clear(struct rq
*rq
)
1139 static inline void hrtick_set(struct rq
*rq
)
1143 static inline void init_rq_hrtick(struct rq
*rq
)
1147 void hrtick_resched(void)
1153 * resched_task - mark a task 'to be rescheduled now'.
1155 * On UP this means the setting of the need_resched flag, on SMP it
1156 * might also involve a cross-CPU call to trigger the scheduler on
1161 #ifndef tsk_is_polling
1162 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1165 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1169 assert_spin_locked(&task_rq(p
)->lock
);
1171 if (unlikely(test_tsk_thread_flag(p
, tif_bit
)))
1174 set_tsk_thread_flag(p
, tif_bit
);
1177 if (cpu
== smp_processor_id())
1180 /* NEED_RESCHED must be visible before we test polling */
1182 if (!tsk_is_polling(p
))
1183 smp_send_reschedule(cpu
);
1186 static void resched_cpu(int cpu
)
1188 struct rq
*rq
= cpu_rq(cpu
);
1189 unsigned long flags
;
1191 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1193 resched_task(cpu_curr(cpu
));
1194 spin_unlock_irqrestore(&rq
->lock
, flags
);
1199 * When add_timer_on() enqueues a timer into the timer wheel of an
1200 * idle CPU then this timer might expire before the next timer event
1201 * which is scheduled to wake up that CPU. In case of a completely
1202 * idle system the next event might even be infinite time into the
1203 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1204 * leaves the inner idle loop so the newly added timer is taken into
1205 * account when the CPU goes back to idle and evaluates the timer
1206 * wheel for the next timer event.
1208 void wake_up_idle_cpu(int cpu
)
1210 struct rq
*rq
= cpu_rq(cpu
);
1212 if (cpu
== smp_processor_id())
1216 * This is safe, as this function is called with the timer
1217 * wheel base lock of (cpu) held. When the CPU is on the way
1218 * to idle and has not yet set rq->curr to idle then it will
1219 * be serialized on the timer wheel base lock and take the new
1220 * timer into account automatically.
1222 if (rq
->curr
!= rq
->idle
)
1226 * We can set TIF_RESCHED on the idle task of the other CPU
1227 * lockless. The worst case is that the other CPU runs the
1228 * idle task through an additional NOOP schedule()
1230 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1232 /* NEED_RESCHED must be visible before we test polling */
1234 if (!tsk_is_polling(rq
->idle
))
1235 smp_send_reschedule(cpu
);
1240 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1242 assert_spin_locked(&task_rq(p
)->lock
);
1243 set_tsk_thread_flag(p
, tif_bit
);
1247 #if BITS_PER_LONG == 32
1248 # define WMULT_CONST (~0UL)
1250 # define WMULT_CONST (1UL << 32)
1253 #define WMULT_SHIFT 32
1256 * Shift right and round:
1258 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1260 static unsigned long
1261 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1262 struct load_weight
*lw
)
1266 if (unlikely(!lw
->inv_weight
))
1267 lw
->inv_weight
= (WMULT_CONST
-lw
->weight
/2) / (lw
->weight
+1);
1269 tmp
= (u64
)delta_exec
* weight
;
1271 * Check whether we'd overflow the 64-bit multiplication:
1273 if (unlikely(tmp
> WMULT_CONST
))
1274 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1277 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1279 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1282 static inline unsigned long
1283 calc_delta_fair(unsigned long delta_exec
, struct load_weight
*lw
)
1285 return calc_delta_mine(delta_exec
, NICE_0_LOAD
, lw
);
1288 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1294 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1301 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1302 * of tasks with abnormal "nice" values across CPUs the contribution that
1303 * each task makes to its run queue's load is weighted according to its
1304 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1305 * scaled version of the new time slice allocation that they receive on time
1309 #define WEIGHT_IDLEPRIO 2
1310 #define WMULT_IDLEPRIO (1 << 31)
1313 * Nice levels are multiplicative, with a gentle 10% change for every
1314 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1315 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1316 * that remained on nice 0.
1318 * The "10% effect" is relative and cumulative: from _any_ nice level,
1319 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1320 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1321 * If a task goes up by ~10% and another task goes down by ~10% then
1322 * the relative distance between them is ~25%.)
1324 static const int prio_to_weight
[40] = {
1325 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1326 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1327 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1328 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1329 /* 0 */ 1024, 820, 655, 526, 423,
1330 /* 5 */ 335, 272, 215, 172, 137,
1331 /* 10 */ 110, 87, 70, 56, 45,
1332 /* 15 */ 36, 29, 23, 18, 15,
1336 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1338 * In cases where the weight does not change often, we can use the
1339 * precalculated inverse to speed up arithmetics by turning divisions
1340 * into multiplications:
1342 static const u32 prio_to_wmult
[40] = {
1343 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1344 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1345 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1346 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1347 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1348 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1349 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1350 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1353 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1356 * runqueue iterator, to support SMP load-balancing between different
1357 * scheduling classes, without having to expose their internal data
1358 * structures to the load-balancing proper:
1360 struct rq_iterator
{
1362 struct task_struct
*(*start
)(void *);
1363 struct task_struct
*(*next
)(void *);
1367 static unsigned long
1368 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1369 unsigned long max_load_move
, struct sched_domain
*sd
,
1370 enum cpu_idle_type idle
, int *all_pinned
,
1371 int *this_best_prio
, struct rq_iterator
*iterator
);
1374 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1375 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1376 struct rq_iterator
*iterator
);
1379 #ifdef CONFIG_CGROUP_CPUACCT
1380 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1382 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1386 static unsigned long source_load(int cpu
, int type
);
1387 static unsigned long target_load(int cpu
, int type
);
1388 static unsigned long cpu_avg_load_per_task(int cpu
);
1389 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1390 #endif /* CONFIG_SMP */
1392 #include "sched_stats.h"
1393 #include "sched_idletask.c"
1394 #include "sched_fair.c"
1395 #include "sched_rt.c"
1396 #ifdef CONFIG_SCHED_DEBUG
1397 # include "sched_debug.c"
1400 #define sched_class_highest (&rt_sched_class)
1402 static inline void inc_load(struct rq
*rq
, const struct task_struct
*p
)
1404 update_load_add(&rq
->load
, p
->se
.load
.weight
);
1407 static inline void dec_load(struct rq
*rq
, const struct task_struct
*p
)
1409 update_load_sub(&rq
->load
, p
->se
.load
.weight
);
1412 static void inc_nr_running(struct task_struct
*p
, struct rq
*rq
)
1418 static void dec_nr_running(struct task_struct
*p
, struct rq
*rq
)
1424 static void set_load_weight(struct task_struct
*p
)
1426 if (task_has_rt_policy(p
)) {
1427 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1428 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1433 * SCHED_IDLE tasks get minimal weight:
1435 if (p
->policy
== SCHED_IDLE
) {
1436 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1437 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1441 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1442 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1445 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1447 sched_info_queued(p
);
1448 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1452 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1454 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1459 * __normal_prio - return the priority that is based on the static prio
1461 static inline int __normal_prio(struct task_struct
*p
)
1463 return p
->static_prio
;
1467 * Calculate the expected normal priority: i.e. priority
1468 * without taking RT-inheritance into account. Might be
1469 * boosted by interactivity modifiers. Changes upon fork,
1470 * setprio syscalls, and whenever the interactivity
1471 * estimator recalculates.
1473 static inline int normal_prio(struct task_struct
*p
)
1477 if (task_has_rt_policy(p
))
1478 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1480 prio
= __normal_prio(p
);
1485 * Calculate the current priority, i.e. the priority
1486 * taken into account by the scheduler. This value might
1487 * be boosted by RT tasks, or might be boosted by
1488 * interactivity modifiers. Will be RT if the task got
1489 * RT-boosted. If not then it returns p->normal_prio.
1491 static int effective_prio(struct task_struct
*p
)
1493 p
->normal_prio
= normal_prio(p
);
1495 * If we are RT tasks or we were boosted to RT priority,
1496 * keep the priority unchanged. Otherwise, update priority
1497 * to the normal priority:
1499 if (!rt_prio(p
->prio
))
1500 return p
->normal_prio
;
1505 * activate_task - move a task to the runqueue.
1507 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1509 if (task_contributes_to_load(p
))
1510 rq
->nr_uninterruptible
--;
1512 enqueue_task(rq
, p
, wakeup
);
1513 inc_nr_running(p
, rq
);
1517 * deactivate_task - remove a task from the runqueue.
1519 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1521 if (task_contributes_to_load(p
))
1522 rq
->nr_uninterruptible
++;
1524 dequeue_task(rq
, p
, sleep
);
1525 dec_nr_running(p
, rq
);
1529 * task_curr - is this task currently executing on a CPU?
1530 * @p: the task in question.
1532 inline int task_curr(const struct task_struct
*p
)
1534 return cpu_curr(task_cpu(p
)) == p
;
1537 /* Used instead of source_load when we know the type == 0 */
1538 unsigned long weighted_cpuload(const int cpu
)
1540 return cpu_rq(cpu
)->load
.weight
;
1543 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1545 set_task_rq(p
, cpu
);
1548 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1549 * successfuly executed on another CPU. We must ensure that updates of
1550 * per-task data have been completed by this moment.
1553 task_thread_info(p
)->cpu
= cpu
;
1557 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1558 const struct sched_class
*prev_class
,
1559 int oldprio
, int running
)
1561 if (prev_class
!= p
->sched_class
) {
1562 if (prev_class
->switched_from
)
1563 prev_class
->switched_from(rq
, p
, running
);
1564 p
->sched_class
->switched_to(rq
, p
, running
);
1566 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1572 * Is this task likely cache-hot:
1575 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1580 * Buddy candidates are cache hot:
1582 if (sched_feat(CACHE_HOT_BUDDY
) && (&p
->se
== cfs_rq_of(&p
->se
)->next
))
1585 if (p
->sched_class
!= &fair_sched_class
)
1588 if (sysctl_sched_migration_cost
== -1)
1590 if (sysctl_sched_migration_cost
== 0)
1593 delta
= now
- p
->se
.exec_start
;
1595 return delta
< (s64
)sysctl_sched_migration_cost
;
1599 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1601 int old_cpu
= task_cpu(p
);
1602 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1603 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1604 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1607 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1609 #ifdef CONFIG_SCHEDSTATS
1610 if (p
->se
.wait_start
)
1611 p
->se
.wait_start
-= clock_offset
;
1612 if (p
->se
.sleep_start
)
1613 p
->se
.sleep_start
-= clock_offset
;
1614 if (p
->se
.block_start
)
1615 p
->se
.block_start
-= clock_offset
;
1616 if (old_cpu
!= new_cpu
) {
1617 schedstat_inc(p
, se
.nr_migrations
);
1618 if (task_hot(p
, old_rq
->clock
, NULL
))
1619 schedstat_inc(p
, se
.nr_forced2_migrations
);
1622 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1623 new_cfsrq
->min_vruntime
;
1625 __set_task_cpu(p
, new_cpu
);
1628 struct migration_req
{
1629 struct list_head list
;
1631 struct task_struct
*task
;
1634 struct completion done
;
1638 * The task's runqueue lock must be held.
1639 * Returns true if you have to wait for migration thread.
1642 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1644 struct rq
*rq
= task_rq(p
);
1647 * If the task is not on a runqueue (and not running), then
1648 * it is sufficient to simply update the task's cpu field.
1650 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1651 set_task_cpu(p
, dest_cpu
);
1655 init_completion(&req
->done
);
1657 req
->dest_cpu
= dest_cpu
;
1658 list_add(&req
->list
, &rq
->migration_queue
);
1664 * wait_task_inactive - wait for a thread to unschedule.
1666 * The caller must ensure that the task *will* unschedule sometime soon,
1667 * else this function might spin for a *long* time. This function can't
1668 * be called with interrupts off, or it may introduce deadlock with
1669 * smp_call_function() if an IPI is sent by the same process we are
1670 * waiting to become inactive.
1672 void wait_task_inactive(struct task_struct
*p
)
1674 unsigned long flags
;
1680 * We do the initial early heuristics without holding
1681 * any task-queue locks at all. We'll only try to get
1682 * the runqueue lock when things look like they will
1688 * If the task is actively running on another CPU
1689 * still, just relax and busy-wait without holding
1692 * NOTE! Since we don't hold any locks, it's not
1693 * even sure that "rq" stays as the right runqueue!
1694 * But we don't care, since "task_running()" will
1695 * return false if the runqueue has changed and p
1696 * is actually now running somewhere else!
1698 while (task_running(rq
, p
))
1702 * Ok, time to look more closely! We need the rq
1703 * lock now, to be *sure*. If we're wrong, we'll
1704 * just go back and repeat.
1706 rq
= task_rq_lock(p
, &flags
);
1707 running
= task_running(rq
, p
);
1708 on_rq
= p
->se
.on_rq
;
1709 task_rq_unlock(rq
, &flags
);
1712 * Was it really running after all now that we
1713 * checked with the proper locks actually held?
1715 * Oops. Go back and try again..
1717 if (unlikely(running
)) {
1723 * It's not enough that it's not actively running,
1724 * it must be off the runqueue _entirely_, and not
1727 * So if it wa still runnable (but just not actively
1728 * running right now), it's preempted, and we should
1729 * yield - it could be a while.
1731 if (unlikely(on_rq
)) {
1732 schedule_timeout_uninterruptible(1);
1737 * Ahh, all good. It wasn't running, and it wasn't
1738 * runnable, which means that it will never become
1739 * running in the future either. We're all done!
1746 * kick_process - kick a running thread to enter/exit the kernel
1747 * @p: the to-be-kicked thread
1749 * Cause a process which is running on another CPU to enter
1750 * kernel-mode, without any delay. (to get signals handled.)
1752 * NOTE: this function doesnt have to take the runqueue lock,
1753 * because all it wants to ensure is that the remote task enters
1754 * the kernel. If the IPI races and the task has been migrated
1755 * to another CPU then no harm is done and the purpose has been
1758 void kick_process(struct task_struct
*p
)
1764 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1765 smp_send_reschedule(cpu
);
1770 * Return a low guess at the load of a migration-source cpu weighted
1771 * according to the scheduling class and "nice" value.
1773 * We want to under-estimate the load of migration sources, to
1774 * balance conservatively.
1776 static unsigned long source_load(int cpu
, int type
)
1778 struct rq
*rq
= cpu_rq(cpu
);
1779 unsigned long total
= weighted_cpuload(cpu
);
1784 return min(rq
->cpu_load
[type
-1], total
);
1788 * Return a high guess at the load of a migration-target cpu weighted
1789 * according to the scheduling class and "nice" value.
1791 static unsigned long target_load(int cpu
, int type
)
1793 struct rq
*rq
= cpu_rq(cpu
);
1794 unsigned long total
= weighted_cpuload(cpu
);
1799 return max(rq
->cpu_load
[type
-1], total
);
1803 * Return the average load per task on the cpu's run queue
1805 static unsigned long cpu_avg_load_per_task(int cpu
)
1807 struct rq
*rq
= cpu_rq(cpu
);
1808 unsigned long total
= weighted_cpuload(cpu
);
1809 unsigned long n
= rq
->nr_running
;
1811 return n
? total
/ n
: SCHED_LOAD_SCALE
;
1815 * find_idlest_group finds and returns the least busy CPU group within the
1818 static struct sched_group
*
1819 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
1821 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
1822 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
1823 int load_idx
= sd
->forkexec_idx
;
1824 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
1827 unsigned long load
, avg_load
;
1831 /* Skip over this group if it has no CPUs allowed */
1832 if (!cpus_intersects(group
->cpumask
, p
->cpus_allowed
))
1835 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
1837 /* Tally up the load of all CPUs in the group */
1840 for_each_cpu_mask(i
, group
->cpumask
) {
1841 /* Bias balancing toward cpus of our domain */
1843 load
= source_load(i
, load_idx
);
1845 load
= target_load(i
, load_idx
);
1850 /* Adjust by relative CPU power of the group */
1851 avg_load
= sg_div_cpu_power(group
,
1852 avg_load
* SCHED_LOAD_SCALE
);
1855 this_load
= avg_load
;
1857 } else if (avg_load
< min_load
) {
1858 min_load
= avg_load
;
1861 } while (group
= group
->next
, group
!= sd
->groups
);
1863 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
1869 * find_idlest_cpu - find the idlest cpu among the cpus in group.
1872 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
,
1875 unsigned long load
, min_load
= ULONG_MAX
;
1879 /* Traverse only the allowed CPUs */
1880 cpus_and(*tmp
, group
->cpumask
, p
->cpus_allowed
);
1882 for_each_cpu_mask(i
, *tmp
) {
1883 load
= weighted_cpuload(i
);
1885 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
1895 * sched_balance_self: balance the current task (running on cpu) in domains
1896 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
1899 * Balance, ie. select the least loaded group.
1901 * Returns the target CPU number, or the same CPU if no balancing is needed.
1903 * preempt must be disabled.
1905 static int sched_balance_self(int cpu
, int flag
)
1907 struct task_struct
*t
= current
;
1908 struct sched_domain
*tmp
, *sd
= NULL
;
1910 for_each_domain(cpu
, tmp
) {
1912 * If power savings logic is enabled for a domain, stop there.
1914 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
1916 if (tmp
->flags
& flag
)
1921 cpumask_t span
, tmpmask
;
1922 struct sched_group
*group
;
1923 int new_cpu
, weight
;
1925 if (!(sd
->flags
& flag
)) {
1931 group
= find_idlest_group(sd
, t
, cpu
);
1937 new_cpu
= find_idlest_cpu(group
, t
, cpu
, &tmpmask
);
1938 if (new_cpu
== -1 || new_cpu
== cpu
) {
1939 /* Now try balancing at a lower domain level of cpu */
1944 /* Now try balancing at a lower domain level of new_cpu */
1947 weight
= cpus_weight(span
);
1948 for_each_domain(cpu
, tmp
) {
1949 if (weight
<= cpus_weight(tmp
->span
))
1951 if (tmp
->flags
& flag
)
1954 /* while loop will break here if sd == NULL */
1960 #endif /* CONFIG_SMP */
1963 * try_to_wake_up - wake up a thread
1964 * @p: the to-be-woken-up thread
1965 * @state: the mask of task states that can be woken
1966 * @sync: do a synchronous wakeup?
1968 * Put it on the run-queue if it's not already there. The "current"
1969 * thread is always on the run-queue (except when the actual
1970 * re-schedule is in progress), and as such you're allowed to do
1971 * the simpler "current->state = TASK_RUNNING" to mark yourself
1972 * runnable without the overhead of this.
1974 * returns failure only if the task is already active.
1976 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
1978 int cpu
, orig_cpu
, this_cpu
, success
= 0;
1979 unsigned long flags
;
1983 if (!sched_feat(SYNC_WAKEUPS
))
1987 rq
= task_rq_lock(p
, &flags
);
1988 old_state
= p
->state
;
1989 if (!(old_state
& state
))
1997 this_cpu
= smp_processor_id();
2000 if (unlikely(task_running(rq
, p
)))
2003 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2004 if (cpu
!= orig_cpu
) {
2005 set_task_cpu(p
, cpu
);
2006 task_rq_unlock(rq
, &flags
);
2007 /* might preempt at this point */
2008 rq
= task_rq_lock(p
, &flags
);
2009 old_state
= p
->state
;
2010 if (!(old_state
& state
))
2015 this_cpu
= smp_processor_id();
2019 #ifdef CONFIG_SCHEDSTATS
2020 schedstat_inc(rq
, ttwu_count
);
2021 if (cpu
== this_cpu
)
2022 schedstat_inc(rq
, ttwu_local
);
2024 struct sched_domain
*sd
;
2025 for_each_domain(this_cpu
, sd
) {
2026 if (cpu_isset(cpu
, sd
->span
)) {
2027 schedstat_inc(sd
, ttwu_wake_remote
);
2035 #endif /* CONFIG_SMP */
2036 schedstat_inc(p
, se
.nr_wakeups
);
2038 schedstat_inc(p
, se
.nr_wakeups_sync
);
2039 if (orig_cpu
!= cpu
)
2040 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2041 if (cpu
== this_cpu
)
2042 schedstat_inc(p
, se
.nr_wakeups_local
);
2044 schedstat_inc(p
, se
.nr_wakeups_remote
);
2045 update_rq_clock(rq
);
2046 activate_task(rq
, p
, 1);
2050 check_preempt_curr(rq
, p
);
2052 p
->state
= TASK_RUNNING
;
2054 if (p
->sched_class
->task_wake_up
)
2055 p
->sched_class
->task_wake_up(rq
, p
);
2058 task_rq_unlock(rq
, &flags
);
2063 int wake_up_process(struct task_struct
*p
)
2065 return try_to_wake_up(p
, TASK_ALL
, 0);
2067 EXPORT_SYMBOL(wake_up_process
);
2069 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2071 return try_to_wake_up(p
, state
, 0);
2075 * Perform scheduler related setup for a newly forked process p.
2076 * p is forked by current.
2078 * __sched_fork() is basic setup used by init_idle() too:
2080 static void __sched_fork(struct task_struct
*p
)
2082 p
->se
.exec_start
= 0;
2083 p
->se
.sum_exec_runtime
= 0;
2084 p
->se
.prev_sum_exec_runtime
= 0;
2085 p
->se
.last_wakeup
= 0;
2086 p
->se
.avg_overlap
= 0;
2088 #ifdef CONFIG_SCHEDSTATS
2089 p
->se
.wait_start
= 0;
2090 p
->se
.sum_sleep_runtime
= 0;
2091 p
->se
.sleep_start
= 0;
2092 p
->se
.block_start
= 0;
2093 p
->se
.sleep_max
= 0;
2094 p
->se
.block_max
= 0;
2096 p
->se
.slice_max
= 0;
2100 INIT_LIST_HEAD(&p
->rt
.run_list
);
2103 #ifdef CONFIG_PREEMPT_NOTIFIERS
2104 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2108 * We mark the process as running here, but have not actually
2109 * inserted it onto the runqueue yet. This guarantees that
2110 * nobody will actually run it, and a signal or other external
2111 * event cannot wake it up and insert it on the runqueue either.
2113 p
->state
= TASK_RUNNING
;
2117 * fork()/clone()-time setup:
2119 void sched_fork(struct task_struct
*p
, int clone_flags
)
2121 int cpu
= get_cpu();
2126 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2128 set_task_cpu(p
, cpu
);
2131 * Make sure we do not leak PI boosting priority to the child:
2133 p
->prio
= current
->normal_prio
;
2134 if (!rt_prio(p
->prio
))
2135 p
->sched_class
= &fair_sched_class
;
2137 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2138 if (likely(sched_info_on()))
2139 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2141 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2144 #ifdef CONFIG_PREEMPT
2145 /* Want to start with kernel preemption disabled. */
2146 task_thread_info(p
)->preempt_count
= 1;
2152 * wake_up_new_task - wake up a newly created task for the first time.
2154 * This function will do some initial scheduler statistics housekeeping
2155 * that must be done for every newly created context, then puts the task
2156 * on the runqueue and wakes it.
2158 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2160 unsigned long flags
;
2163 rq
= task_rq_lock(p
, &flags
);
2164 BUG_ON(p
->state
!= TASK_RUNNING
);
2165 update_rq_clock(rq
);
2167 p
->prio
= effective_prio(p
);
2169 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2170 activate_task(rq
, p
, 0);
2173 * Let the scheduling class do new task startup
2174 * management (if any):
2176 p
->sched_class
->task_new(rq
, p
);
2177 inc_nr_running(p
, rq
);
2179 check_preempt_curr(rq
, p
);
2181 if (p
->sched_class
->task_wake_up
)
2182 p
->sched_class
->task_wake_up(rq
, p
);
2184 task_rq_unlock(rq
, &flags
);
2187 #ifdef CONFIG_PREEMPT_NOTIFIERS
2190 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2191 * @notifier: notifier struct to register
2193 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2195 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2197 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2200 * preempt_notifier_unregister - no longer interested in preemption notifications
2201 * @notifier: notifier struct to unregister
2203 * This is safe to call from within a preemption notifier.
2205 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2207 hlist_del(¬ifier
->link
);
2209 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2211 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2213 struct preempt_notifier
*notifier
;
2214 struct hlist_node
*node
;
2216 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2217 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2221 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2222 struct task_struct
*next
)
2224 struct preempt_notifier
*notifier
;
2225 struct hlist_node
*node
;
2227 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2228 notifier
->ops
->sched_out(notifier
, next
);
2233 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2238 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2239 struct task_struct
*next
)
2246 * prepare_task_switch - prepare to switch tasks
2247 * @rq: the runqueue preparing to switch
2248 * @prev: the current task that is being switched out
2249 * @next: the task we are going to switch to.
2251 * This is called with the rq lock held and interrupts off. It must
2252 * be paired with a subsequent finish_task_switch after the context
2255 * prepare_task_switch sets up locking and calls architecture specific
2259 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2260 struct task_struct
*next
)
2262 fire_sched_out_preempt_notifiers(prev
, next
);
2263 prepare_lock_switch(rq
, next
);
2264 prepare_arch_switch(next
);
2268 * finish_task_switch - clean up after a task-switch
2269 * @rq: runqueue associated with task-switch
2270 * @prev: the thread we just switched away from.
2272 * finish_task_switch must be called after the context switch, paired
2273 * with a prepare_task_switch call before the context switch.
2274 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2275 * and do any other architecture-specific cleanup actions.
2277 * Note that we may have delayed dropping an mm in context_switch(). If
2278 * so, we finish that here outside of the runqueue lock. (Doing it
2279 * with the lock held can cause deadlocks; see schedule() for
2282 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2283 __releases(rq
->lock
)
2285 struct mm_struct
*mm
= rq
->prev_mm
;
2291 * A task struct has one reference for the use as "current".
2292 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2293 * schedule one last time. The schedule call will never return, and
2294 * the scheduled task must drop that reference.
2295 * The test for TASK_DEAD must occur while the runqueue locks are
2296 * still held, otherwise prev could be scheduled on another cpu, die
2297 * there before we look at prev->state, and then the reference would
2299 * Manfred Spraul <manfred@colorfullife.com>
2301 prev_state
= prev
->state
;
2302 finish_arch_switch(prev
);
2303 finish_lock_switch(rq
, prev
);
2305 if (current
->sched_class
->post_schedule
)
2306 current
->sched_class
->post_schedule(rq
);
2309 fire_sched_in_preempt_notifiers(current
);
2312 if (unlikely(prev_state
== TASK_DEAD
)) {
2314 * Remove function-return probe instances associated with this
2315 * task and put them back on the free list.
2317 kprobe_flush_task(prev
);
2318 put_task_struct(prev
);
2323 * schedule_tail - first thing a freshly forked thread must call.
2324 * @prev: the thread we just switched away from.
2326 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2327 __releases(rq
->lock
)
2329 struct rq
*rq
= this_rq();
2331 finish_task_switch(rq
, prev
);
2332 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2333 /* In this case, finish_task_switch does not reenable preemption */
2336 if (current
->set_child_tid
)
2337 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2341 * context_switch - switch to the new MM and the new
2342 * thread's register state.
2345 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2346 struct task_struct
*next
)
2348 struct mm_struct
*mm
, *oldmm
;
2350 prepare_task_switch(rq
, prev
, next
);
2352 oldmm
= prev
->active_mm
;
2354 * For paravirt, this is coupled with an exit in switch_to to
2355 * combine the page table reload and the switch backend into
2358 arch_enter_lazy_cpu_mode();
2360 if (unlikely(!mm
)) {
2361 next
->active_mm
= oldmm
;
2362 atomic_inc(&oldmm
->mm_count
);
2363 enter_lazy_tlb(oldmm
, next
);
2365 switch_mm(oldmm
, mm
, next
);
2367 if (unlikely(!prev
->mm
)) {
2368 prev
->active_mm
= NULL
;
2369 rq
->prev_mm
= oldmm
;
2372 * Since the runqueue lock will be released by the next
2373 * task (which is an invalid locking op but in the case
2374 * of the scheduler it's an obvious special-case), so we
2375 * do an early lockdep release here:
2377 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2378 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2381 /* Here we just switch the register state and the stack. */
2382 switch_to(prev
, next
, prev
);
2386 * this_rq must be evaluated again because prev may have moved
2387 * CPUs since it called schedule(), thus the 'rq' on its stack
2388 * frame will be invalid.
2390 finish_task_switch(this_rq(), prev
);
2394 * nr_running, nr_uninterruptible and nr_context_switches:
2396 * externally visible scheduler statistics: current number of runnable
2397 * threads, current number of uninterruptible-sleeping threads, total
2398 * number of context switches performed since bootup.
2400 unsigned long nr_running(void)
2402 unsigned long i
, sum
= 0;
2404 for_each_online_cpu(i
)
2405 sum
+= cpu_rq(i
)->nr_running
;
2410 unsigned long nr_uninterruptible(void)
2412 unsigned long i
, sum
= 0;
2414 for_each_possible_cpu(i
)
2415 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2418 * Since we read the counters lockless, it might be slightly
2419 * inaccurate. Do not allow it to go below zero though:
2421 if (unlikely((long)sum
< 0))
2427 unsigned long long nr_context_switches(void)
2430 unsigned long long sum
= 0;
2432 for_each_possible_cpu(i
)
2433 sum
+= cpu_rq(i
)->nr_switches
;
2438 unsigned long nr_iowait(void)
2440 unsigned long i
, sum
= 0;
2442 for_each_possible_cpu(i
)
2443 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2448 unsigned long nr_active(void)
2450 unsigned long i
, running
= 0, uninterruptible
= 0;
2452 for_each_online_cpu(i
) {
2453 running
+= cpu_rq(i
)->nr_running
;
2454 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2457 if (unlikely((long)uninterruptible
< 0))
2458 uninterruptible
= 0;
2460 return running
+ uninterruptible
;
2464 * Update rq->cpu_load[] statistics. This function is usually called every
2465 * scheduler tick (TICK_NSEC).
2467 static void update_cpu_load(struct rq
*this_rq
)
2469 unsigned long this_load
= this_rq
->load
.weight
;
2472 this_rq
->nr_load_updates
++;
2474 /* Update our load: */
2475 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2476 unsigned long old_load
, new_load
;
2478 /* scale is effectively 1 << i now, and >> i divides by scale */
2480 old_load
= this_rq
->cpu_load
[i
];
2481 new_load
= this_load
;
2483 * Round up the averaging division if load is increasing. This
2484 * prevents us from getting stuck on 9 if the load is 10, for
2487 if (new_load
> old_load
)
2488 new_load
+= scale
-1;
2489 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2496 * double_rq_lock - safely lock two runqueues
2498 * Note this does not disable interrupts like task_rq_lock,
2499 * you need to do so manually before calling.
2501 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2502 __acquires(rq1
->lock
)
2503 __acquires(rq2
->lock
)
2505 BUG_ON(!irqs_disabled());
2507 spin_lock(&rq1
->lock
);
2508 __acquire(rq2
->lock
); /* Fake it out ;) */
2511 spin_lock(&rq1
->lock
);
2512 spin_lock(&rq2
->lock
);
2514 spin_lock(&rq2
->lock
);
2515 spin_lock(&rq1
->lock
);
2518 update_rq_clock(rq1
);
2519 update_rq_clock(rq2
);
2523 * double_rq_unlock - safely unlock two runqueues
2525 * Note this does not restore interrupts like task_rq_unlock,
2526 * you need to do so manually after calling.
2528 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2529 __releases(rq1
->lock
)
2530 __releases(rq2
->lock
)
2532 spin_unlock(&rq1
->lock
);
2534 spin_unlock(&rq2
->lock
);
2536 __release(rq2
->lock
);
2540 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2542 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
2543 __releases(this_rq
->lock
)
2544 __acquires(busiest
->lock
)
2545 __acquires(this_rq
->lock
)
2549 if (unlikely(!irqs_disabled())) {
2550 /* printk() doesn't work good under rq->lock */
2551 spin_unlock(&this_rq
->lock
);
2554 if (unlikely(!spin_trylock(&busiest
->lock
))) {
2555 if (busiest
< this_rq
) {
2556 spin_unlock(&this_rq
->lock
);
2557 spin_lock(&busiest
->lock
);
2558 spin_lock(&this_rq
->lock
);
2561 spin_lock(&busiest
->lock
);
2567 * If dest_cpu is allowed for this process, migrate the task to it.
2568 * This is accomplished by forcing the cpu_allowed mask to only
2569 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2570 * the cpu_allowed mask is restored.
2572 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2574 struct migration_req req
;
2575 unsigned long flags
;
2578 rq
= task_rq_lock(p
, &flags
);
2579 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
)
2580 || unlikely(cpu_is_offline(dest_cpu
)))
2583 /* force the process onto the specified CPU */
2584 if (migrate_task(p
, dest_cpu
, &req
)) {
2585 /* Need to wait for migration thread (might exit: take ref). */
2586 struct task_struct
*mt
= rq
->migration_thread
;
2588 get_task_struct(mt
);
2589 task_rq_unlock(rq
, &flags
);
2590 wake_up_process(mt
);
2591 put_task_struct(mt
);
2592 wait_for_completion(&req
.done
);
2597 task_rq_unlock(rq
, &flags
);
2601 * sched_exec - execve() is a valuable balancing opportunity, because at
2602 * this point the task has the smallest effective memory and cache footprint.
2604 void sched_exec(void)
2606 int new_cpu
, this_cpu
= get_cpu();
2607 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2609 if (new_cpu
!= this_cpu
)
2610 sched_migrate_task(current
, new_cpu
);
2614 * pull_task - move a task from a remote runqueue to the local runqueue.
2615 * Both runqueues must be locked.
2617 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2618 struct rq
*this_rq
, int this_cpu
)
2620 deactivate_task(src_rq
, p
, 0);
2621 set_task_cpu(p
, this_cpu
);
2622 activate_task(this_rq
, p
, 0);
2624 * Note that idle threads have a prio of MAX_PRIO, for this test
2625 * to be always true for them.
2627 check_preempt_curr(this_rq
, p
);
2631 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2634 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2635 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2639 * We do not migrate tasks that are:
2640 * 1) running (obviously), or
2641 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2642 * 3) are cache-hot on their current CPU.
2644 if (!cpu_isset(this_cpu
, p
->cpus_allowed
)) {
2645 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
2650 if (task_running(rq
, p
)) {
2651 schedstat_inc(p
, se
.nr_failed_migrations_running
);
2656 * Aggressive migration if:
2657 * 1) task is cache cold, or
2658 * 2) too many balance attempts have failed.
2661 if (!task_hot(p
, rq
->clock
, sd
) ||
2662 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
2663 #ifdef CONFIG_SCHEDSTATS
2664 if (task_hot(p
, rq
->clock
, sd
)) {
2665 schedstat_inc(sd
, lb_hot_gained
[idle
]);
2666 schedstat_inc(p
, se
.nr_forced_migrations
);
2672 if (task_hot(p
, rq
->clock
, sd
)) {
2673 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
2679 static unsigned long
2680 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2681 unsigned long max_load_move
, struct sched_domain
*sd
,
2682 enum cpu_idle_type idle
, int *all_pinned
,
2683 int *this_best_prio
, struct rq_iterator
*iterator
)
2685 int loops
= 0, pulled
= 0, pinned
= 0, skip_for_load
;
2686 struct task_struct
*p
;
2687 long rem_load_move
= max_load_move
;
2689 if (max_load_move
== 0)
2695 * Start the load-balancing iterator:
2697 p
= iterator
->start(iterator
->arg
);
2699 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
2702 * To help distribute high priority tasks across CPUs we don't
2703 * skip a task if it will be the highest priority task (i.e. smallest
2704 * prio value) on its new queue regardless of its load weight
2706 skip_for_load
= (p
->se
.load
.weight
>> 1) > rem_load_move
+
2707 SCHED_LOAD_SCALE_FUZZ
;
2708 if ((skip_for_load
&& p
->prio
>= *this_best_prio
) ||
2709 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2710 p
= iterator
->next(iterator
->arg
);
2714 pull_task(busiest
, p
, this_rq
, this_cpu
);
2716 rem_load_move
-= p
->se
.load
.weight
;
2719 * We only want to steal up to the prescribed amount of weighted load.
2721 if (rem_load_move
> 0) {
2722 if (p
->prio
< *this_best_prio
)
2723 *this_best_prio
= p
->prio
;
2724 p
= iterator
->next(iterator
->arg
);
2729 * Right now, this is one of only two places pull_task() is called,
2730 * so we can safely collect pull_task() stats here rather than
2731 * inside pull_task().
2733 schedstat_add(sd
, lb_gained
[idle
], pulled
);
2736 *all_pinned
= pinned
;
2738 return max_load_move
- rem_load_move
;
2742 * move_tasks tries to move up to max_load_move weighted load from busiest to
2743 * this_rq, as part of a balancing operation within domain "sd".
2744 * Returns 1 if successful and 0 otherwise.
2746 * Called with both runqueues locked.
2748 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2749 unsigned long max_load_move
,
2750 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2753 const struct sched_class
*class = sched_class_highest
;
2754 unsigned long total_load_moved
= 0;
2755 int this_best_prio
= this_rq
->curr
->prio
;
2759 class->load_balance(this_rq
, this_cpu
, busiest
,
2760 max_load_move
- total_load_moved
,
2761 sd
, idle
, all_pinned
, &this_best_prio
);
2762 class = class->next
;
2763 } while (class && max_load_move
> total_load_moved
);
2765 return total_load_moved
> 0;
2769 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2770 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2771 struct rq_iterator
*iterator
)
2773 struct task_struct
*p
= iterator
->start(iterator
->arg
);
2777 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2778 pull_task(busiest
, p
, this_rq
, this_cpu
);
2780 * Right now, this is only the second place pull_task()
2781 * is called, so we can safely collect pull_task()
2782 * stats here rather than inside pull_task().
2784 schedstat_inc(sd
, lb_gained
[idle
]);
2788 p
= iterator
->next(iterator
->arg
);
2795 * move_one_task tries to move exactly one task from busiest to this_rq, as
2796 * part of active balancing operations within "domain".
2797 * Returns 1 if successful and 0 otherwise.
2799 * Called with both runqueues locked.
2801 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2802 struct sched_domain
*sd
, enum cpu_idle_type idle
)
2804 const struct sched_class
*class;
2806 for (class = sched_class_highest
; class; class = class->next
)
2807 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
2814 * find_busiest_group finds and returns the busiest CPU group within the
2815 * domain. It calculates and returns the amount of weighted load which
2816 * should be moved to restore balance via the imbalance parameter.
2818 static struct sched_group
*
2819 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
2820 unsigned long *imbalance
, enum cpu_idle_type idle
,
2821 int *sd_idle
, const cpumask_t
*cpus
, int *balance
)
2823 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2824 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
2825 unsigned long max_pull
;
2826 unsigned long busiest_load_per_task
, busiest_nr_running
;
2827 unsigned long this_load_per_task
, this_nr_running
;
2828 int load_idx
, group_imb
= 0;
2829 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2830 int power_savings_balance
= 1;
2831 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
2832 unsigned long min_nr_running
= ULONG_MAX
;
2833 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
2836 max_load
= this_load
= total_load
= total_pwr
= 0;
2837 busiest_load_per_task
= busiest_nr_running
= 0;
2838 this_load_per_task
= this_nr_running
= 0;
2839 if (idle
== CPU_NOT_IDLE
)
2840 load_idx
= sd
->busy_idx
;
2841 else if (idle
== CPU_NEWLY_IDLE
)
2842 load_idx
= sd
->newidle_idx
;
2844 load_idx
= sd
->idle_idx
;
2847 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
2850 int __group_imb
= 0;
2851 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
2852 unsigned long sum_nr_running
, sum_weighted_load
;
2854 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
2857 balance_cpu
= first_cpu(group
->cpumask
);
2859 /* Tally up the load of all CPUs in the group */
2860 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
2862 min_cpu_load
= ~0UL;
2864 for_each_cpu_mask(i
, group
->cpumask
) {
2867 if (!cpu_isset(i
, *cpus
))
2872 if (*sd_idle
&& rq
->nr_running
)
2875 /* Bias balancing toward cpus of our domain */
2877 if (idle_cpu(i
) && !first_idle_cpu
) {
2882 load
= target_load(i
, load_idx
);
2884 load
= source_load(i
, load_idx
);
2885 if (load
> max_cpu_load
)
2886 max_cpu_load
= load
;
2887 if (min_cpu_load
> load
)
2888 min_cpu_load
= load
;
2892 sum_nr_running
+= rq
->nr_running
;
2893 sum_weighted_load
+= weighted_cpuload(i
);
2897 * First idle cpu or the first cpu(busiest) in this sched group
2898 * is eligible for doing load balancing at this and above
2899 * domains. In the newly idle case, we will allow all the cpu's
2900 * to do the newly idle load balance.
2902 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
2903 balance_cpu
!= this_cpu
&& balance
) {
2908 total_load
+= avg_load
;
2909 total_pwr
+= group
->__cpu_power
;
2911 /* Adjust by relative CPU power of the group */
2912 avg_load
= sg_div_cpu_power(group
,
2913 avg_load
* SCHED_LOAD_SCALE
);
2915 if ((max_cpu_load
- min_cpu_load
) > SCHED_LOAD_SCALE
)
2918 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
2921 this_load
= avg_load
;
2923 this_nr_running
= sum_nr_running
;
2924 this_load_per_task
= sum_weighted_load
;
2925 } else if (avg_load
> max_load
&&
2926 (sum_nr_running
> group_capacity
|| __group_imb
)) {
2927 max_load
= avg_load
;
2929 busiest_nr_running
= sum_nr_running
;
2930 busiest_load_per_task
= sum_weighted_load
;
2931 group_imb
= __group_imb
;
2934 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2936 * Busy processors will not participate in power savings
2939 if (idle
== CPU_NOT_IDLE
||
2940 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
2944 * If the local group is idle or completely loaded
2945 * no need to do power savings balance at this domain
2947 if (local_group
&& (this_nr_running
>= group_capacity
||
2949 power_savings_balance
= 0;
2952 * If a group is already running at full capacity or idle,
2953 * don't include that group in power savings calculations
2955 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
2960 * Calculate the group which has the least non-idle load.
2961 * This is the group from where we need to pick up the load
2964 if ((sum_nr_running
< min_nr_running
) ||
2965 (sum_nr_running
== min_nr_running
&&
2966 first_cpu(group
->cpumask
) <
2967 first_cpu(group_min
->cpumask
))) {
2969 min_nr_running
= sum_nr_running
;
2970 min_load_per_task
= sum_weighted_load
/
2975 * Calculate the group which is almost near its
2976 * capacity but still has some space to pick up some load
2977 * from other group and save more power
2979 if (sum_nr_running
<= group_capacity
- 1) {
2980 if (sum_nr_running
> leader_nr_running
||
2981 (sum_nr_running
== leader_nr_running
&&
2982 first_cpu(group
->cpumask
) >
2983 first_cpu(group_leader
->cpumask
))) {
2984 group_leader
= group
;
2985 leader_nr_running
= sum_nr_running
;
2990 group
= group
->next
;
2991 } while (group
!= sd
->groups
);
2993 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
2996 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
2998 if (this_load
>= avg_load
||
2999 100*max_load
<= sd
->imbalance_pct
*this_load
)
3002 busiest_load_per_task
/= busiest_nr_running
;
3004 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3007 * We're trying to get all the cpus to the average_load, so we don't
3008 * want to push ourselves above the average load, nor do we wish to
3009 * reduce the max loaded cpu below the average load, as either of these
3010 * actions would just result in more rebalancing later, and ping-pong
3011 * tasks around. Thus we look for the minimum possible imbalance.
3012 * Negative imbalances (*we* are more loaded than anyone else) will
3013 * be counted as no imbalance for these purposes -- we can't fix that
3014 * by pulling tasks to us. Be careful of negative numbers as they'll
3015 * appear as very large values with unsigned longs.
3017 if (max_load
<= busiest_load_per_task
)
3021 * In the presence of smp nice balancing, certain scenarios can have
3022 * max load less than avg load(as we skip the groups at or below
3023 * its cpu_power, while calculating max_load..)
3025 if (max_load
< avg_load
) {
3027 goto small_imbalance
;
3030 /* Don't want to pull so many tasks that a group would go idle */
3031 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3033 /* How much load to actually move to equalise the imbalance */
3034 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3035 (avg_load
- this_load
) * this->__cpu_power
)
3039 * if *imbalance is less than the average load per runnable task
3040 * there is no gaurantee that any tasks will be moved so we'll have
3041 * a think about bumping its value to force at least one task to be
3044 if (*imbalance
< busiest_load_per_task
) {
3045 unsigned long tmp
, pwr_now
, pwr_move
;
3049 pwr_move
= pwr_now
= 0;
3051 if (this_nr_running
) {
3052 this_load_per_task
/= this_nr_running
;
3053 if (busiest_load_per_task
> this_load_per_task
)
3056 this_load_per_task
= SCHED_LOAD_SCALE
;
3058 if (max_load
- this_load
+ SCHED_LOAD_SCALE_FUZZ
>=
3059 busiest_load_per_task
* imbn
) {
3060 *imbalance
= busiest_load_per_task
;
3065 * OK, we don't have enough imbalance to justify moving tasks,
3066 * however we may be able to increase total CPU power used by
3070 pwr_now
+= busiest
->__cpu_power
*
3071 min(busiest_load_per_task
, max_load
);
3072 pwr_now
+= this->__cpu_power
*
3073 min(this_load_per_task
, this_load
);
3074 pwr_now
/= SCHED_LOAD_SCALE
;
3076 /* Amount of load we'd subtract */
3077 tmp
= sg_div_cpu_power(busiest
,
3078 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3080 pwr_move
+= busiest
->__cpu_power
*
3081 min(busiest_load_per_task
, max_load
- tmp
);
3083 /* Amount of load we'd add */
3084 if (max_load
* busiest
->__cpu_power
<
3085 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3086 tmp
= sg_div_cpu_power(this,
3087 max_load
* busiest
->__cpu_power
);
3089 tmp
= sg_div_cpu_power(this,
3090 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3091 pwr_move
+= this->__cpu_power
*
3092 min(this_load_per_task
, this_load
+ tmp
);
3093 pwr_move
/= SCHED_LOAD_SCALE
;
3095 /* Move if we gain throughput */
3096 if (pwr_move
> pwr_now
)
3097 *imbalance
= busiest_load_per_task
;
3103 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3104 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3107 if (this == group_leader
&& group_leader
!= group_min
) {
3108 *imbalance
= min_load_per_task
;
3118 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3121 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3122 unsigned long imbalance
, const cpumask_t
*cpus
)
3124 struct rq
*busiest
= NULL
, *rq
;
3125 unsigned long max_load
= 0;
3128 for_each_cpu_mask(i
, group
->cpumask
) {
3131 if (!cpu_isset(i
, *cpus
))
3135 wl
= weighted_cpuload(i
);
3137 if (rq
->nr_running
== 1 && wl
> imbalance
)
3140 if (wl
> max_load
) {
3150 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3151 * so long as it is large enough.
3153 #define MAX_PINNED_INTERVAL 512
3156 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3157 * tasks if there is an imbalance.
3159 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3160 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3161 int *balance
, cpumask_t
*cpus
)
3163 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3164 struct sched_group
*group
;
3165 unsigned long imbalance
;
3167 unsigned long flags
;
3172 * When power savings policy is enabled for the parent domain, idle
3173 * sibling can pick up load irrespective of busy siblings. In this case,
3174 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3175 * portraying it as CPU_NOT_IDLE.
3177 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3178 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3181 schedstat_inc(sd
, lb_count
[idle
]);
3184 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3191 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3195 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3197 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3201 BUG_ON(busiest
== this_rq
);
3203 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3206 if (busiest
->nr_running
> 1) {
3208 * Attempt to move tasks. If find_busiest_group has found
3209 * an imbalance but busiest->nr_running <= 1, the group is
3210 * still unbalanced. ld_moved simply stays zero, so it is
3211 * correctly treated as an imbalance.
3213 local_irq_save(flags
);
3214 double_rq_lock(this_rq
, busiest
);
3215 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3216 imbalance
, sd
, idle
, &all_pinned
);
3217 double_rq_unlock(this_rq
, busiest
);
3218 local_irq_restore(flags
);
3221 * some other cpu did the load balance for us.
3223 if (ld_moved
&& this_cpu
!= smp_processor_id())
3224 resched_cpu(this_cpu
);
3226 /* All tasks on this runqueue were pinned by CPU affinity */
3227 if (unlikely(all_pinned
)) {
3228 cpu_clear(cpu_of(busiest
), *cpus
);
3229 if (!cpus_empty(*cpus
))
3236 schedstat_inc(sd
, lb_failed
[idle
]);
3237 sd
->nr_balance_failed
++;
3239 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3241 spin_lock_irqsave(&busiest
->lock
, flags
);
3243 /* don't kick the migration_thread, if the curr
3244 * task on busiest cpu can't be moved to this_cpu
3246 if (!cpu_isset(this_cpu
, busiest
->curr
->cpus_allowed
)) {
3247 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3249 goto out_one_pinned
;
3252 if (!busiest
->active_balance
) {
3253 busiest
->active_balance
= 1;
3254 busiest
->push_cpu
= this_cpu
;
3257 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3259 wake_up_process(busiest
->migration_thread
);
3262 * We've kicked active balancing, reset the failure
3265 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3268 sd
->nr_balance_failed
= 0;
3270 if (likely(!active_balance
)) {
3271 /* We were unbalanced, so reset the balancing interval */
3272 sd
->balance_interval
= sd
->min_interval
;
3275 * If we've begun active balancing, start to back off. This
3276 * case may not be covered by the all_pinned logic if there
3277 * is only 1 task on the busy runqueue (because we don't call
3280 if (sd
->balance_interval
< sd
->max_interval
)
3281 sd
->balance_interval
*= 2;
3284 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3285 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3290 schedstat_inc(sd
, lb_balanced
[idle
]);
3292 sd
->nr_balance_failed
= 0;
3295 /* tune up the balancing interval */
3296 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3297 (sd
->balance_interval
< sd
->max_interval
))
3298 sd
->balance_interval
*= 2;
3300 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3301 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3307 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3308 * tasks if there is an imbalance.
3310 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3311 * this_rq is locked.
3314 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3317 struct sched_group
*group
;
3318 struct rq
*busiest
= NULL
;
3319 unsigned long imbalance
;
3327 * When power savings policy is enabled for the parent domain, idle
3328 * sibling can pick up load irrespective of busy siblings. In this case,
3329 * let the state of idle sibling percolate up as IDLE, instead of
3330 * portraying it as CPU_NOT_IDLE.
3332 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3333 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3336 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3338 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3339 &sd_idle
, cpus
, NULL
);
3341 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3345 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3347 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3351 BUG_ON(busiest
== this_rq
);
3353 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3356 if (busiest
->nr_running
> 1) {
3357 /* Attempt to move tasks */
3358 double_lock_balance(this_rq
, busiest
);
3359 /* this_rq->clock is already updated */
3360 update_rq_clock(busiest
);
3361 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3362 imbalance
, sd
, CPU_NEWLY_IDLE
,
3364 spin_unlock(&busiest
->lock
);
3366 if (unlikely(all_pinned
)) {
3367 cpu_clear(cpu_of(busiest
), *cpus
);
3368 if (!cpus_empty(*cpus
))
3374 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3375 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3376 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3379 sd
->nr_balance_failed
= 0;
3384 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3385 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3386 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3388 sd
->nr_balance_failed
= 0;
3394 * idle_balance is called by schedule() if this_cpu is about to become
3395 * idle. Attempts to pull tasks from other CPUs.
3397 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3399 struct sched_domain
*sd
;
3400 int pulled_task
= -1;
3401 unsigned long next_balance
= jiffies
+ HZ
;
3404 for_each_domain(this_cpu
, sd
) {
3405 unsigned long interval
;
3407 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3410 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3411 /* If we've pulled tasks over stop searching: */
3412 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3415 interval
= msecs_to_jiffies(sd
->balance_interval
);
3416 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3417 next_balance
= sd
->last_balance
+ interval
;
3421 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3423 * We are going idle. next_balance may be set based on
3424 * a busy processor. So reset next_balance.
3426 this_rq
->next_balance
= next_balance
;
3431 * active_load_balance is run by migration threads. It pushes running tasks
3432 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3433 * running on each physical CPU where possible, and avoids physical /
3434 * logical imbalances.
3436 * Called with busiest_rq locked.
3438 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3440 int target_cpu
= busiest_rq
->push_cpu
;
3441 struct sched_domain
*sd
;
3442 struct rq
*target_rq
;
3444 /* Is there any task to move? */
3445 if (busiest_rq
->nr_running
<= 1)
3448 target_rq
= cpu_rq(target_cpu
);
3451 * This condition is "impossible", if it occurs
3452 * we need to fix it. Originally reported by
3453 * Bjorn Helgaas on a 128-cpu setup.
3455 BUG_ON(busiest_rq
== target_rq
);
3457 /* move a task from busiest_rq to target_rq */
3458 double_lock_balance(busiest_rq
, target_rq
);
3459 update_rq_clock(busiest_rq
);
3460 update_rq_clock(target_rq
);
3462 /* Search for an sd spanning us and the target CPU. */
3463 for_each_domain(target_cpu
, sd
) {
3464 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3465 cpu_isset(busiest_cpu
, sd
->span
))
3470 schedstat_inc(sd
, alb_count
);
3472 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3474 schedstat_inc(sd
, alb_pushed
);
3476 schedstat_inc(sd
, alb_failed
);
3478 spin_unlock(&target_rq
->lock
);
3483 atomic_t load_balancer
;
3485 } nohz ____cacheline_aligned
= {
3486 .load_balancer
= ATOMIC_INIT(-1),
3487 .cpu_mask
= CPU_MASK_NONE
,
3491 * This routine will try to nominate the ilb (idle load balancing)
3492 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3493 * load balancing on behalf of all those cpus. If all the cpus in the system
3494 * go into this tickless mode, then there will be no ilb owner (as there is
3495 * no need for one) and all the cpus will sleep till the next wakeup event
3498 * For the ilb owner, tick is not stopped. And this tick will be used
3499 * for idle load balancing. ilb owner will still be part of
3502 * While stopping the tick, this cpu will become the ilb owner if there
3503 * is no other owner. And will be the owner till that cpu becomes busy
3504 * or if all cpus in the system stop their ticks at which point
3505 * there is no need for ilb owner.
3507 * When the ilb owner becomes busy, it nominates another owner, during the
3508 * next busy scheduler_tick()
3510 int select_nohz_load_balancer(int stop_tick
)
3512 int cpu
= smp_processor_id();
3515 cpu_set(cpu
, nohz
.cpu_mask
);
3516 cpu_rq(cpu
)->in_nohz_recently
= 1;
3519 * If we are going offline and still the leader, give up!
3521 if (cpu_is_offline(cpu
) &&
3522 atomic_read(&nohz
.load_balancer
) == cpu
) {
3523 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3528 /* time for ilb owner also to sleep */
3529 if (cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3530 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3531 atomic_set(&nohz
.load_balancer
, -1);
3535 if (atomic_read(&nohz
.load_balancer
) == -1) {
3536 /* make me the ilb owner */
3537 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
3539 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
3542 if (!cpu_isset(cpu
, nohz
.cpu_mask
))
3545 cpu_clear(cpu
, nohz
.cpu_mask
);
3547 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3548 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3555 static DEFINE_SPINLOCK(balancing
);
3558 * It checks each scheduling domain to see if it is due to be balanced,
3559 * and initiates a balancing operation if so.
3561 * Balancing parameters are set up in arch_init_sched_domains.
3563 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
3566 struct rq
*rq
= cpu_rq(cpu
);
3567 unsigned long interval
;
3568 struct sched_domain
*sd
;
3569 /* Earliest time when we have to do rebalance again */
3570 unsigned long next_balance
= jiffies
+ 60*HZ
;
3571 int update_next_balance
= 0;
3574 for_each_domain(cpu
, sd
) {
3575 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3578 interval
= sd
->balance_interval
;
3579 if (idle
!= CPU_IDLE
)
3580 interval
*= sd
->busy_factor
;
3582 /* scale ms to jiffies */
3583 interval
= msecs_to_jiffies(interval
);
3584 if (unlikely(!interval
))
3586 if (interval
> HZ
*NR_CPUS
/10)
3587 interval
= HZ
*NR_CPUS
/10;
3590 if (sd
->flags
& SD_SERIALIZE
) {
3591 if (!spin_trylock(&balancing
))
3595 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
3596 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, &tmp
)) {
3598 * We've pulled tasks over so either we're no
3599 * longer idle, or one of our SMT siblings is
3602 idle
= CPU_NOT_IDLE
;
3604 sd
->last_balance
= jiffies
;
3606 if (sd
->flags
& SD_SERIALIZE
)
3607 spin_unlock(&balancing
);
3609 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
3610 next_balance
= sd
->last_balance
+ interval
;
3611 update_next_balance
= 1;
3615 * Stop the load balance at this level. There is another
3616 * CPU in our sched group which is doing load balancing more
3624 * next_balance will be updated only when there is a need.
3625 * When the cpu is attached to null domain for ex, it will not be
3628 if (likely(update_next_balance
))
3629 rq
->next_balance
= next_balance
;
3633 * run_rebalance_domains is triggered when needed from the scheduler tick.
3634 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3635 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3637 static void run_rebalance_domains(struct softirq_action
*h
)
3639 int this_cpu
= smp_processor_id();
3640 struct rq
*this_rq
= cpu_rq(this_cpu
);
3641 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
3642 CPU_IDLE
: CPU_NOT_IDLE
;
3644 rebalance_domains(this_cpu
, idle
);
3648 * If this cpu is the owner for idle load balancing, then do the
3649 * balancing on behalf of the other idle cpus whose ticks are
3652 if (this_rq
->idle_at_tick
&&
3653 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
3654 cpumask_t cpus
= nohz
.cpu_mask
;
3658 cpu_clear(this_cpu
, cpus
);
3659 for_each_cpu_mask(balance_cpu
, cpus
) {
3661 * If this cpu gets work to do, stop the load balancing
3662 * work being done for other cpus. Next load
3663 * balancing owner will pick it up.
3668 rebalance_domains(balance_cpu
, CPU_IDLE
);
3670 rq
= cpu_rq(balance_cpu
);
3671 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
3672 this_rq
->next_balance
= rq
->next_balance
;
3679 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3681 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3682 * idle load balancing owner or decide to stop the periodic load balancing,
3683 * if the whole system is idle.
3685 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
3689 * If we were in the nohz mode recently and busy at the current
3690 * scheduler tick, then check if we need to nominate new idle
3693 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
3694 rq
->in_nohz_recently
= 0;
3696 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
3697 cpu_clear(cpu
, nohz
.cpu_mask
);
3698 atomic_set(&nohz
.load_balancer
, -1);
3701 if (atomic_read(&nohz
.load_balancer
) == -1) {
3703 * simple selection for now: Nominate the
3704 * first cpu in the nohz list to be the next
3707 * TBD: Traverse the sched domains and nominate
3708 * the nearest cpu in the nohz.cpu_mask.
3710 int ilb
= first_cpu(nohz
.cpu_mask
);
3712 if (ilb
< nr_cpu_ids
)
3718 * If this cpu is idle and doing idle load balancing for all the
3719 * cpus with ticks stopped, is it time for that to stop?
3721 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
3722 cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3728 * If this cpu is idle and the idle load balancing is done by
3729 * someone else, then no need raise the SCHED_SOFTIRQ
3731 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
3732 cpu_isset(cpu
, nohz
.cpu_mask
))
3735 if (time_after_eq(jiffies
, rq
->next_balance
))
3736 raise_softirq(SCHED_SOFTIRQ
);
3739 #else /* CONFIG_SMP */
3742 * on UP we do not need to balance between CPUs:
3744 static inline void idle_balance(int cpu
, struct rq
*rq
)
3750 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3752 EXPORT_PER_CPU_SYMBOL(kstat
);
3755 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3756 * that have not yet been banked in case the task is currently running.
3758 unsigned long long task_sched_runtime(struct task_struct
*p
)
3760 unsigned long flags
;
3764 rq
= task_rq_lock(p
, &flags
);
3765 ns
= p
->se
.sum_exec_runtime
;
3766 if (task_current(rq
, p
)) {
3767 update_rq_clock(rq
);
3768 delta_exec
= rq
->clock
- p
->se
.exec_start
;
3769 if ((s64
)delta_exec
> 0)
3772 task_rq_unlock(rq
, &flags
);
3778 * Account user cpu time to a process.
3779 * @p: the process that the cpu time gets accounted to
3780 * @cputime: the cpu time spent in user space since the last update
3782 void account_user_time(struct task_struct
*p
, cputime_t cputime
)
3784 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3787 p
->utime
= cputime_add(p
->utime
, cputime
);
3789 /* Add user time to cpustat. */
3790 tmp
= cputime_to_cputime64(cputime
);
3791 if (TASK_NICE(p
) > 0)
3792 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3794 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3798 * Account guest cpu time to a process.
3799 * @p: the process that the cpu time gets accounted to
3800 * @cputime: the cpu time spent in virtual machine since the last update
3802 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
)
3805 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3807 tmp
= cputime_to_cputime64(cputime
);
3809 p
->utime
= cputime_add(p
->utime
, cputime
);
3810 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3812 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3813 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3817 * Account scaled user cpu time to a process.
3818 * @p: the process that the cpu time gets accounted to
3819 * @cputime: the cpu time spent in user space since the last update
3821 void account_user_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3823 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime
);
3827 * Account system cpu time to a process.
3828 * @p: the process that the cpu time gets accounted to
3829 * @hardirq_offset: the offset to subtract from hardirq_count()
3830 * @cputime: the cpu time spent in kernel space since the last update
3832 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3835 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3836 struct rq
*rq
= this_rq();
3839 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0))
3840 return account_guest_time(p
, cputime
);
3842 p
->stime
= cputime_add(p
->stime
, cputime
);
3844 /* Add system time to cpustat. */
3845 tmp
= cputime_to_cputime64(cputime
);
3846 if (hardirq_count() - hardirq_offset
)
3847 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3848 else if (softirq_count())
3849 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3850 else if (p
!= rq
->idle
)
3851 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3852 else if (atomic_read(&rq
->nr_iowait
) > 0)
3853 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3855 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3856 /* Account for system time used */
3857 acct_update_integrals(p
);
3861 * Account scaled system cpu time to a process.
3862 * @p: the process that the cpu time gets accounted to
3863 * @hardirq_offset: the offset to subtract from hardirq_count()
3864 * @cputime: the cpu time spent in kernel space since the last update
3866 void account_system_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3868 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime
);
3872 * Account for involuntary wait time.
3873 * @p: the process from which the cpu time has been stolen
3874 * @steal: the cpu time spent in involuntary wait
3876 void account_steal_time(struct task_struct
*p
, cputime_t steal
)
3878 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3879 cputime64_t tmp
= cputime_to_cputime64(steal
);
3880 struct rq
*rq
= this_rq();
3882 if (p
== rq
->idle
) {
3883 p
->stime
= cputime_add(p
->stime
, steal
);
3884 if (atomic_read(&rq
->nr_iowait
) > 0)
3885 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3887 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3889 cpustat
->steal
= cputime64_add(cpustat
->steal
, tmp
);
3893 * This function gets called by the timer code, with HZ frequency.
3894 * We call it with interrupts disabled.
3896 * It also gets called by the fork code, when changing the parent's
3899 void scheduler_tick(void)
3901 int cpu
= smp_processor_id();
3902 struct rq
*rq
= cpu_rq(cpu
);
3903 struct task_struct
*curr
= rq
->curr
;
3904 u64 next_tick
= rq
->tick_timestamp
+ TICK_NSEC
;
3906 spin_lock(&rq
->lock
);
3907 __update_rq_clock(rq
);
3909 * Let rq->clock advance by at least TICK_NSEC:
3911 if (unlikely(rq
->clock
< next_tick
)) {
3912 rq
->clock
= next_tick
;
3913 rq
->clock_underflows
++;
3915 rq
->tick_timestamp
= rq
->clock
;
3916 update_last_tick_seen(rq
);
3917 update_cpu_load(rq
);
3918 curr
->sched_class
->task_tick(rq
, curr
, 0);
3919 spin_unlock(&rq
->lock
);
3922 rq
->idle_at_tick
= idle_cpu(cpu
);
3923 trigger_load_balance(rq
, cpu
);
3927 #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
3929 void __kprobes
add_preempt_count(int val
)
3934 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3936 preempt_count() += val
;
3938 * Spinlock count overflowing soon?
3940 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3943 EXPORT_SYMBOL(add_preempt_count
);
3945 void __kprobes
sub_preempt_count(int val
)
3950 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3953 * Is the spinlock portion underflowing?
3955 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3956 !(preempt_count() & PREEMPT_MASK
)))
3959 preempt_count() -= val
;
3961 EXPORT_SYMBOL(sub_preempt_count
);
3966 * Print scheduling while atomic bug:
3968 static noinline
void __schedule_bug(struct task_struct
*prev
)
3970 struct pt_regs
*regs
= get_irq_regs();
3972 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3973 prev
->comm
, prev
->pid
, preempt_count());
3975 debug_show_held_locks(prev
);
3976 if (irqs_disabled())
3977 print_irqtrace_events(prev
);
3986 * Various schedule()-time debugging checks and statistics:
3988 static inline void schedule_debug(struct task_struct
*prev
)
3991 * Test if we are atomic. Since do_exit() needs to call into
3992 * schedule() atomically, we ignore that path for now.
3993 * Otherwise, whine if we are scheduling when we should not be.
3995 if (unlikely(in_atomic_preempt_off()) && unlikely(!prev
->exit_state
))
3996 __schedule_bug(prev
);
3998 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4000 schedstat_inc(this_rq(), sched_count
);
4001 #ifdef CONFIG_SCHEDSTATS
4002 if (unlikely(prev
->lock_depth
>= 0)) {
4003 schedstat_inc(this_rq(), bkl_count
);
4004 schedstat_inc(prev
, sched_info
.bkl_count
);
4010 * Pick up the highest-prio task:
4012 static inline struct task_struct
*
4013 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4015 const struct sched_class
*class;
4016 struct task_struct
*p
;
4019 * Optimization: we know that if all tasks are in
4020 * the fair class we can call that function directly:
4022 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4023 p
= fair_sched_class
.pick_next_task(rq
);
4028 class = sched_class_highest
;
4030 p
= class->pick_next_task(rq
);
4034 * Will never be NULL as the idle class always
4035 * returns a non-NULL p:
4037 class = class->next
;
4042 * schedule() is the main scheduler function.
4044 asmlinkage
void __sched
schedule(void)
4046 struct task_struct
*prev
, *next
;
4047 unsigned long *switch_count
;
4053 cpu
= smp_processor_id();
4057 switch_count
= &prev
->nivcsw
;
4059 release_kernel_lock(prev
);
4060 need_resched_nonpreemptible
:
4062 schedule_debug(prev
);
4067 * Do the rq-clock update outside the rq lock:
4069 local_irq_disable();
4070 __update_rq_clock(rq
);
4071 spin_lock(&rq
->lock
);
4072 clear_tsk_need_resched(prev
);
4074 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4075 if (unlikely((prev
->state
& TASK_INTERRUPTIBLE
) &&
4076 signal_pending(prev
))) {
4077 prev
->state
= TASK_RUNNING
;
4079 deactivate_task(rq
, prev
, 1);
4081 switch_count
= &prev
->nvcsw
;
4085 if (prev
->sched_class
->pre_schedule
)
4086 prev
->sched_class
->pre_schedule(rq
, prev
);
4089 if (unlikely(!rq
->nr_running
))
4090 idle_balance(cpu
, rq
);
4092 prev
->sched_class
->put_prev_task(rq
, prev
);
4093 next
= pick_next_task(rq
, prev
);
4095 sched_info_switch(prev
, next
);
4097 if (likely(prev
!= next
)) {
4102 context_switch(rq
, prev
, next
); /* unlocks the rq */
4104 * the context switch might have flipped the stack from under
4105 * us, hence refresh the local variables.
4107 cpu
= smp_processor_id();
4110 spin_unlock_irq(&rq
->lock
);
4114 if (unlikely(reacquire_kernel_lock(current
) < 0))
4115 goto need_resched_nonpreemptible
;
4117 preempt_enable_no_resched();
4118 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4121 EXPORT_SYMBOL(schedule
);
4123 #ifdef CONFIG_PREEMPT
4125 * this is the entry point to schedule() from in-kernel preemption
4126 * off of preempt_enable. Kernel preemptions off return from interrupt
4127 * occur there and call schedule directly.
4129 asmlinkage
void __sched
preempt_schedule(void)
4131 struct thread_info
*ti
= current_thread_info();
4132 struct task_struct
*task
= current
;
4133 int saved_lock_depth
;
4136 * If there is a non-zero preempt_count or interrupts are disabled,
4137 * we do not want to preempt the current task. Just return..
4139 if (likely(ti
->preempt_count
|| irqs_disabled()))
4143 add_preempt_count(PREEMPT_ACTIVE
);
4146 * We keep the big kernel semaphore locked, but we
4147 * clear ->lock_depth so that schedule() doesnt
4148 * auto-release the semaphore:
4150 saved_lock_depth
= task
->lock_depth
;
4151 task
->lock_depth
= -1;
4153 task
->lock_depth
= saved_lock_depth
;
4154 sub_preempt_count(PREEMPT_ACTIVE
);
4157 * Check again in case we missed a preemption opportunity
4158 * between schedule and now.
4161 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4163 EXPORT_SYMBOL(preempt_schedule
);
4166 * this is the entry point to schedule() from kernel preemption
4167 * off of irq context.
4168 * Note, that this is called and return with irqs disabled. This will
4169 * protect us against recursive calling from irq.
4171 asmlinkage
void __sched
preempt_schedule_irq(void)
4173 struct thread_info
*ti
= current_thread_info();
4174 struct task_struct
*task
= current
;
4175 int saved_lock_depth
;
4177 /* Catch callers which need to be fixed */
4178 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4181 add_preempt_count(PREEMPT_ACTIVE
);
4184 * We keep the big kernel semaphore locked, but we
4185 * clear ->lock_depth so that schedule() doesnt
4186 * auto-release the semaphore:
4188 saved_lock_depth
= task
->lock_depth
;
4189 task
->lock_depth
= -1;
4192 local_irq_disable();
4193 task
->lock_depth
= saved_lock_depth
;
4194 sub_preempt_count(PREEMPT_ACTIVE
);
4197 * Check again in case we missed a preemption opportunity
4198 * between schedule and now.
4201 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4204 #endif /* CONFIG_PREEMPT */
4206 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4209 return try_to_wake_up(curr
->private, mode
, sync
);
4211 EXPORT_SYMBOL(default_wake_function
);
4214 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4215 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4216 * number) then we wake all the non-exclusive tasks and one exclusive task.
4218 * There are circumstances in which we can try to wake a task which has already
4219 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4220 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4222 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4223 int nr_exclusive
, int sync
, void *key
)
4225 wait_queue_t
*curr
, *next
;
4227 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4228 unsigned flags
= curr
->flags
;
4230 if (curr
->func(curr
, mode
, sync
, key
) &&
4231 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4237 * __wake_up - wake up threads blocked on a waitqueue.
4239 * @mode: which threads
4240 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4241 * @key: is directly passed to the wakeup function
4243 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4244 int nr_exclusive
, void *key
)
4246 unsigned long flags
;
4248 spin_lock_irqsave(&q
->lock
, flags
);
4249 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4250 spin_unlock_irqrestore(&q
->lock
, flags
);
4252 EXPORT_SYMBOL(__wake_up
);
4255 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4257 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4259 __wake_up_common(q
, mode
, 1, 0, NULL
);
4263 * __wake_up_sync - wake up threads blocked on a waitqueue.
4265 * @mode: which threads
4266 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4268 * The sync wakeup differs that the waker knows that it will schedule
4269 * away soon, so while the target thread will be woken up, it will not
4270 * be migrated to another CPU - ie. the two threads are 'synchronized'
4271 * with each other. This can prevent needless bouncing between CPUs.
4273 * On UP it can prevent extra preemption.
4276 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4278 unsigned long flags
;
4284 if (unlikely(!nr_exclusive
))
4287 spin_lock_irqsave(&q
->lock
, flags
);
4288 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4289 spin_unlock_irqrestore(&q
->lock
, flags
);
4291 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4293 void complete(struct completion
*x
)
4295 unsigned long flags
;
4297 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4299 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4300 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4302 EXPORT_SYMBOL(complete
);
4304 void complete_all(struct completion
*x
)
4306 unsigned long flags
;
4308 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4309 x
->done
+= UINT_MAX
/2;
4310 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4311 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4313 EXPORT_SYMBOL(complete_all
);
4315 static inline long __sched
4316 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4319 DECLARE_WAITQUEUE(wait
, current
);
4321 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4322 __add_wait_queue_tail(&x
->wait
, &wait
);
4324 if ((state
== TASK_INTERRUPTIBLE
&&
4325 signal_pending(current
)) ||
4326 (state
== TASK_KILLABLE
&&
4327 fatal_signal_pending(current
))) {
4328 __remove_wait_queue(&x
->wait
, &wait
);
4329 return -ERESTARTSYS
;
4331 __set_current_state(state
);
4332 spin_unlock_irq(&x
->wait
.lock
);
4333 timeout
= schedule_timeout(timeout
);
4334 spin_lock_irq(&x
->wait
.lock
);
4336 __remove_wait_queue(&x
->wait
, &wait
);
4340 __remove_wait_queue(&x
->wait
, &wait
);
4347 wait_for_common(struct completion
*x
, long timeout
, int state
)
4351 spin_lock_irq(&x
->wait
.lock
);
4352 timeout
= do_wait_for_common(x
, timeout
, state
);
4353 spin_unlock_irq(&x
->wait
.lock
);
4357 void __sched
wait_for_completion(struct completion
*x
)
4359 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4361 EXPORT_SYMBOL(wait_for_completion
);
4363 unsigned long __sched
4364 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4366 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4368 EXPORT_SYMBOL(wait_for_completion_timeout
);
4370 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4372 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4373 if (t
== -ERESTARTSYS
)
4377 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4379 unsigned long __sched
4380 wait_for_completion_interruptible_timeout(struct completion
*x
,
4381 unsigned long timeout
)
4383 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4385 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4387 int __sched
wait_for_completion_killable(struct completion
*x
)
4389 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4390 if (t
== -ERESTARTSYS
)
4394 EXPORT_SYMBOL(wait_for_completion_killable
);
4397 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4399 unsigned long flags
;
4402 init_waitqueue_entry(&wait
, current
);
4404 __set_current_state(state
);
4406 spin_lock_irqsave(&q
->lock
, flags
);
4407 __add_wait_queue(q
, &wait
);
4408 spin_unlock(&q
->lock
);
4409 timeout
= schedule_timeout(timeout
);
4410 spin_lock_irq(&q
->lock
);
4411 __remove_wait_queue(q
, &wait
);
4412 spin_unlock_irqrestore(&q
->lock
, flags
);
4417 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4419 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4421 EXPORT_SYMBOL(interruptible_sleep_on
);
4424 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4426 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4428 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4430 void __sched
sleep_on(wait_queue_head_t
*q
)
4432 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4434 EXPORT_SYMBOL(sleep_on
);
4436 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4438 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4440 EXPORT_SYMBOL(sleep_on_timeout
);
4442 #ifdef CONFIG_RT_MUTEXES
4445 * rt_mutex_setprio - set the current priority of a task
4447 * @prio: prio value (kernel-internal form)
4449 * This function changes the 'effective' priority of a task. It does
4450 * not touch ->normal_prio like __setscheduler().
4452 * Used by the rt_mutex code to implement priority inheritance logic.
4454 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4456 unsigned long flags
;
4457 int oldprio
, on_rq
, running
;
4459 const struct sched_class
*prev_class
= p
->sched_class
;
4461 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4463 rq
= task_rq_lock(p
, &flags
);
4464 update_rq_clock(rq
);
4467 on_rq
= p
->se
.on_rq
;
4468 running
= task_current(rq
, p
);
4470 dequeue_task(rq
, p
, 0);
4472 p
->sched_class
->put_prev_task(rq
, p
);
4475 p
->sched_class
= &rt_sched_class
;
4477 p
->sched_class
= &fair_sched_class
;
4482 p
->sched_class
->set_curr_task(rq
);
4484 enqueue_task(rq
, p
, 0);
4486 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4488 task_rq_unlock(rq
, &flags
);
4493 void set_user_nice(struct task_struct
*p
, long nice
)
4495 int old_prio
, delta
, on_rq
;
4496 unsigned long flags
;
4499 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4502 * We have to be careful, if called from sys_setpriority(),
4503 * the task might be in the middle of scheduling on another CPU.
4505 rq
= task_rq_lock(p
, &flags
);
4506 update_rq_clock(rq
);
4508 * The RT priorities are set via sched_setscheduler(), but we still
4509 * allow the 'normal' nice value to be set - but as expected
4510 * it wont have any effect on scheduling until the task is
4511 * SCHED_FIFO/SCHED_RR:
4513 if (task_has_rt_policy(p
)) {
4514 p
->static_prio
= NICE_TO_PRIO(nice
);
4517 on_rq
= p
->se
.on_rq
;
4519 dequeue_task(rq
, p
, 0);
4523 p
->static_prio
= NICE_TO_PRIO(nice
);
4526 p
->prio
= effective_prio(p
);
4527 delta
= p
->prio
- old_prio
;
4530 enqueue_task(rq
, p
, 0);
4533 * If the task increased its priority or is running and
4534 * lowered its priority, then reschedule its CPU:
4536 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4537 resched_task(rq
->curr
);
4540 task_rq_unlock(rq
, &flags
);
4542 EXPORT_SYMBOL(set_user_nice
);
4545 * can_nice - check if a task can reduce its nice value
4549 int can_nice(const struct task_struct
*p
, const int nice
)
4551 /* convert nice value [19,-20] to rlimit style value [1,40] */
4552 int nice_rlim
= 20 - nice
;
4554 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
4555 capable(CAP_SYS_NICE
));
4558 #ifdef __ARCH_WANT_SYS_NICE
4561 * sys_nice - change the priority of the current process.
4562 * @increment: priority increment
4564 * sys_setpriority is a more generic, but much slower function that
4565 * does similar things.
4567 asmlinkage
long sys_nice(int increment
)
4572 * Setpriority might change our priority at the same moment.
4573 * We don't have to worry. Conceptually one call occurs first
4574 * and we have a single winner.
4576 if (increment
< -40)
4581 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
4587 if (increment
< 0 && !can_nice(current
, nice
))
4590 retval
= security_task_setnice(current
, nice
);
4594 set_user_nice(current
, nice
);
4601 * task_prio - return the priority value of a given task.
4602 * @p: the task in question.
4604 * This is the priority value as seen by users in /proc.
4605 * RT tasks are offset by -200. Normal tasks are centered
4606 * around 0, value goes from -16 to +15.
4608 int task_prio(const struct task_struct
*p
)
4610 return p
->prio
- MAX_RT_PRIO
;
4614 * task_nice - return the nice value of a given task.
4615 * @p: the task in question.
4617 int task_nice(const struct task_struct
*p
)
4619 return TASK_NICE(p
);
4621 EXPORT_SYMBOL(task_nice
);
4624 * idle_cpu - is a given cpu idle currently?
4625 * @cpu: the processor in question.
4627 int idle_cpu(int cpu
)
4629 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4633 * idle_task - return the idle task for a given cpu.
4634 * @cpu: the processor in question.
4636 struct task_struct
*idle_task(int cpu
)
4638 return cpu_rq(cpu
)->idle
;
4642 * find_process_by_pid - find a process with a matching PID value.
4643 * @pid: the pid in question.
4645 static struct task_struct
*find_process_by_pid(pid_t pid
)
4647 return pid
? find_task_by_vpid(pid
) : current
;
4650 /* Actually do priority change: must hold rq lock. */
4652 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4654 BUG_ON(p
->se
.on_rq
);
4657 switch (p
->policy
) {
4661 p
->sched_class
= &fair_sched_class
;
4665 p
->sched_class
= &rt_sched_class
;
4669 p
->rt_priority
= prio
;
4670 p
->normal_prio
= normal_prio(p
);
4671 /* we are holding p->pi_lock already */
4672 p
->prio
= rt_mutex_getprio(p
);
4677 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4678 * @p: the task in question.
4679 * @policy: new policy.
4680 * @param: structure containing the new RT priority.
4682 * NOTE that the task may be already dead.
4684 int sched_setscheduler(struct task_struct
*p
, int policy
,
4685 struct sched_param
*param
)
4687 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4688 unsigned long flags
;
4689 const struct sched_class
*prev_class
= p
->sched_class
;
4692 /* may grab non-irq protected spin_locks */
4693 BUG_ON(in_interrupt());
4695 /* double check policy once rq lock held */
4697 policy
= oldpolicy
= p
->policy
;
4698 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4699 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4700 policy
!= SCHED_IDLE
)
4703 * Valid priorities for SCHED_FIFO and SCHED_RR are
4704 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4705 * SCHED_BATCH and SCHED_IDLE is 0.
4707 if (param
->sched_priority
< 0 ||
4708 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4709 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4711 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4715 * Allow unprivileged RT tasks to decrease priority:
4717 if (!capable(CAP_SYS_NICE
)) {
4718 if (rt_policy(policy
)) {
4719 unsigned long rlim_rtprio
;
4721 if (!lock_task_sighand(p
, &flags
))
4723 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
4724 unlock_task_sighand(p
, &flags
);
4726 /* can't set/change the rt policy */
4727 if (policy
!= p
->policy
&& !rlim_rtprio
)
4730 /* can't increase priority */
4731 if (param
->sched_priority
> p
->rt_priority
&&
4732 param
->sched_priority
> rlim_rtprio
)
4736 * Like positive nice levels, dont allow tasks to
4737 * move out of SCHED_IDLE either:
4739 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4742 /* can't change other user's priorities */
4743 if ((current
->euid
!= p
->euid
) &&
4744 (current
->euid
!= p
->uid
))
4748 #ifdef CONFIG_RT_GROUP_SCHED
4750 * Do not allow realtime tasks into groups that have no runtime
4753 if (rt_policy(policy
) && task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
4757 retval
= security_task_setscheduler(p
, policy
, param
);
4761 * make sure no PI-waiters arrive (or leave) while we are
4762 * changing the priority of the task:
4764 spin_lock_irqsave(&p
->pi_lock
, flags
);
4766 * To be able to change p->policy safely, the apropriate
4767 * runqueue lock must be held.
4769 rq
= __task_rq_lock(p
);
4770 /* recheck policy now with rq lock held */
4771 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4772 policy
= oldpolicy
= -1;
4773 __task_rq_unlock(rq
);
4774 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4777 update_rq_clock(rq
);
4778 on_rq
= p
->se
.on_rq
;
4779 running
= task_current(rq
, p
);
4781 deactivate_task(rq
, p
, 0);
4783 p
->sched_class
->put_prev_task(rq
, p
);
4786 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4789 p
->sched_class
->set_curr_task(rq
);
4791 activate_task(rq
, p
, 0);
4793 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4795 __task_rq_unlock(rq
);
4796 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4798 rt_mutex_adjust_pi(p
);
4802 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4805 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4807 struct sched_param lparam
;
4808 struct task_struct
*p
;
4811 if (!param
|| pid
< 0)
4813 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4818 p
= find_process_by_pid(pid
);
4820 retval
= sched_setscheduler(p
, policy
, &lparam
);
4827 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4828 * @pid: the pid in question.
4829 * @policy: new policy.
4830 * @param: structure containing the new RT priority.
4833 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4835 /* negative values for policy are not valid */
4839 return do_sched_setscheduler(pid
, policy
, param
);
4843 * sys_sched_setparam - set/change the RT priority of a thread
4844 * @pid: the pid in question.
4845 * @param: structure containing the new RT priority.
4847 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
4849 return do_sched_setscheduler(pid
, -1, param
);
4853 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4854 * @pid: the pid in question.
4856 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
4858 struct task_struct
*p
;
4865 read_lock(&tasklist_lock
);
4866 p
= find_process_by_pid(pid
);
4868 retval
= security_task_getscheduler(p
);
4872 read_unlock(&tasklist_lock
);
4877 * sys_sched_getscheduler - get the RT priority of a thread
4878 * @pid: the pid in question.
4879 * @param: structure containing the RT priority.
4881 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
4883 struct sched_param lp
;
4884 struct task_struct
*p
;
4887 if (!param
|| pid
< 0)
4890 read_lock(&tasklist_lock
);
4891 p
= find_process_by_pid(pid
);
4896 retval
= security_task_getscheduler(p
);
4900 lp
.sched_priority
= p
->rt_priority
;
4901 read_unlock(&tasklist_lock
);
4904 * This one might sleep, we cannot do it with a spinlock held ...
4906 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4911 read_unlock(&tasklist_lock
);
4915 long sched_setaffinity(pid_t pid
, const cpumask_t
*in_mask
)
4917 cpumask_t cpus_allowed
;
4918 cpumask_t new_mask
= *in_mask
;
4919 struct task_struct
*p
;
4923 read_lock(&tasklist_lock
);
4925 p
= find_process_by_pid(pid
);
4927 read_unlock(&tasklist_lock
);
4933 * It is not safe to call set_cpus_allowed with the
4934 * tasklist_lock held. We will bump the task_struct's
4935 * usage count and then drop tasklist_lock.
4938 read_unlock(&tasklist_lock
);
4941 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
4942 !capable(CAP_SYS_NICE
))
4945 retval
= security_task_setscheduler(p
, 0, NULL
);
4949 cpuset_cpus_allowed(p
, &cpus_allowed
);
4950 cpus_and(new_mask
, new_mask
, cpus_allowed
);
4952 retval
= set_cpus_allowed_ptr(p
, &new_mask
);
4955 cpuset_cpus_allowed(p
, &cpus_allowed
);
4956 if (!cpus_subset(new_mask
, cpus_allowed
)) {
4958 * We must have raced with a concurrent cpuset
4959 * update. Just reset the cpus_allowed to the
4960 * cpuset's cpus_allowed
4962 new_mask
= cpus_allowed
;
4972 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4973 cpumask_t
*new_mask
)
4975 if (len
< sizeof(cpumask_t
)) {
4976 memset(new_mask
, 0, sizeof(cpumask_t
));
4977 } else if (len
> sizeof(cpumask_t
)) {
4978 len
= sizeof(cpumask_t
);
4980 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4984 * sys_sched_setaffinity - set the cpu affinity of a process
4985 * @pid: pid of the process
4986 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4987 * @user_mask_ptr: user-space pointer to the new cpu mask
4989 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
4990 unsigned long __user
*user_mask_ptr
)
4995 retval
= get_user_cpu_mask(user_mask_ptr
, len
, &new_mask
);
4999 return sched_setaffinity(pid
, &new_mask
);
5003 * Represents all cpu's present in the system
5004 * In systems capable of hotplug, this map could dynamically grow
5005 * as new cpu's are detected in the system via any platform specific
5006 * method, such as ACPI for e.g.
5009 cpumask_t cpu_present_map __read_mostly
;
5010 EXPORT_SYMBOL(cpu_present_map
);
5013 cpumask_t cpu_online_map __read_mostly
= CPU_MASK_ALL
;
5014 EXPORT_SYMBOL(cpu_online_map
);
5016 cpumask_t cpu_possible_map __read_mostly
= CPU_MASK_ALL
;
5017 EXPORT_SYMBOL(cpu_possible_map
);
5020 long sched_getaffinity(pid_t pid
, cpumask_t
*mask
)
5022 struct task_struct
*p
;
5026 read_lock(&tasklist_lock
);
5029 p
= find_process_by_pid(pid
);
5033 retval
= security_task_getscheduler(p
);
5037 cpus_and(*mask
, p
->cpus_allowed
, cpu_online_map
);
5040 read_unlock(&tasklist_lock
);
5047 * sys_sched_getaffinity - get the cpu affinity of a process
5048 * @pid: pid of the process
5049 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5050 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5052 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5053 unsigned long __user
*user_mask_ptr
)
5058 if (len
< sizeof(cpumask_t
))
5061 ret
= sched_getaffinity(pid
, &mask
);
5065 if (copy_to_user(user_mask_ptr
, &mask
, sizeof(cpumask_t
)))
5068 return sizeof(cpumask_t
);
5072 * sys_sched_yield - yield the current processor to other threads.
5074 * This function yields the current CPU to other tasks. If there are no
5075 * other threads running on this CPU then this function will return.
5077 asmlinkage
long sys_sched_yield(void)
5079 struct rq
*rq
= this_rq_lock();
5081 schedstat_inc(rq
, yld_count
);
5082 current
->sched_class
->yield_task(rq
);
5085 * Since we are going to call schedule() anyway, there's
5086 * no need to preempt or enable interrupts:
5088 __release(rq
->lock
);
5089 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5090 _raw_spin_unlock(&rq
->lock
);
5091 preempt_enable_no_resched();
5098 static void __cond_resched(void)
5100 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5101 __might_sleep(__FILE__
, __LINE__
);
5104 * The BKS might be reacquired before we have dropped
5105 * PREEMPT_ACTIVE, which could trigger a second
5106 * cond_resched() call.
5109 add_preempt_count(PREEMPT_ACTIVE
);
5111 sub_preempt_count(PREEMPT_ACTIVE
);
5112 } while (need_resched());
5115 #if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY)
5116 int __sched
_cond_resched(void)
5118 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5119 system_state
== SYSTEM_RUNNING
) {
5125 EXPORT_SYMBOL(_cond_resched
);
5129 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5130 * call schedule, and on return reacquire the lock.
5132 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5133 * operations here to prevent schedule() from being called twice (once via
5134 * spin_unlock(), once by hand).
5136 int cond_resched_lock(spinlock_t
*lock
)
5138 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5141 if (spin_needbreak(lock
) || resched
) {
5143 if (resched
&& need_resched())
5152 EXPORT_SYMBOL(cond_resched_lock
);
5154 int __sched
cond_resched_softirq(void)
5156 BUG_ON(!in_softirq());
5158 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5166 EXPORT_SYMBOL(cond_resched_softirq
);
5169 * yield - yield the current processor to other threads.
5171 * This is a shortcut for kernel-space yielding - it marks the
5172 * thread runnable and calls sys_sched_yield().
5174 void __sched
yield(void)
5176 set_current_state(TASK_RUNNING
);
5179 EXPORT_SYMBOL(yield
);
5182 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5183 * that process accounting knows that this is a task in IO wait state.
5185 * But don't do that if it is a deliberate, throttling IO wait (this task
5186 * has set its backing_dev_info: the queue against which it should throttle)
5188 void __sched
io_schedule(void)
5190 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5192 delayacct_blkio_start();
5193 atomic_inc(&rq
->nr_iowait
);
5195 atomic_dec(&rq
->nr_iowait
);
5196 delayacct_blkio_end();
5198 EXPORT_SYMBOL(io_schedule
);
5200 long __sched
io_schedule_timeout(long timeout
)
5202 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5205 delayacct_blkio_start();
5206 atomic_inc(&rq
->nr_iowait
);
5207 ret
= schedule_timeout(timeout
);
5208 atomic_dec(&rq
->nr_iowait
);
5209 delayacct_blkio_end();
5214 * sys_sched_get_priority_max - return maximum RT priority.
5215 * @policy: scheduling class.
5217 * this syscall returns the maximum rt_priority that can be used
5218 * by a given scheduling class.
5220 asmlinkage
long sys_sched_get_priority_max(int policy
)
5227 ret
= MAX_USER_RT_PRIO
-1;
5239 * sys_sched_get_priority_min - return minimum RT priority.
5240 * @policy: scheduling class.
5242 * this syscall returns the minimum rt_priority that can be used
5243 * by a given scheduling class.
5245 asmlinkage
long sys_sched_get_priority_min(int policy
)
5263 * sys_sched_rr_get_interval - return the default timeslice of a process.
5264 * @pid: pid of the process.
5265 * @interval: userspace pointer to the timeslice value.
5267 * this syscall writes the default timeslice value of a given process
5268 * into the user-space timespec buffer. A value of '0' means infinity.
5271 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5273 struct task_struct
*p
;
5274 unsigned int time_slice
;
5282 read_lock(&tasklist_lock
);
5283 p
= find_process_by_pid(pid
);
5287 retval
= security_task_getscheduler(p
);
5292 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5293 * tasks that are on an otherwise idle runqueue:
5296 if (p
->policy
== SCHED_RR
) {
5297 time_slice
= DEF_TIMESLICE
;
5298 } else if (p
->policy
!= SCHED_FIFO
) {
5299 struct sched_entity
*se
= &p
->se
;
5300 unsigned long flags
;
5303 rq
= task_rq_lock(p
, &flags
);
5304 if (rq
->cfs
.load
.weight
)
5305 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5306 task_rq_unlock(rq
, &flags
);
5308 read_unlock(&tasklist_lock
);
5309 jiffies_to_timespec(time_slice
, &t
);
5310 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5314 read_unlock(&tasklist_lock
);
5318 static const char stat_nam
[] = "RSDTtZX";
5320 void sched_show_task(struct task_struct
*p
)
5322 unsigned long free
= 0;
5325 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5326 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5327 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5328 #if BITS_PER_LONG == 32
5329 if (state
== TASK_RUNNING
)
5330 printk(KERN_CONT
" running ");
5332 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5334 if (state
== TASK_RUNNING
)
5335 printk(KERN_CONT
" running task ");
5337 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5339 #ifdef CONFIG_DEBUG_STACK_USAGE
5341 unsigned long *n
= end_of_stack(p
);
5344 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
5347 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
5348 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
5350 show_stack(p
, NULL
);
5353 void show_state_filter(unsigned long state_filter
)
5355 struct task_struct
*g
, *p
;
5357 #if BITS_PER_LONG == 32
5359 " task PC stack pid father\n");
5362 " task PC stack pid father\n");
5364 read_lock(&tasklist_lock
);
5365 do_each_thread(g
, p
) {
5367 * reset the NMI-timeout, listing all files on a slow
5368 * console might take alot of time:
5370 touch_nmi_watchdog();
5371 if (!state_filter
|| (p
->state
& state_filter
))
5373 } while_each_thread(g
, p
);
5375 touch_all_softlockup_watchdogs();
5377 #ifdef CONFIG_SCHED_DEBUG
5378 sysrq_sched_debug_show();
5380 read_unlock(&tasklist_lock
);
5382 * Only show locks if all tasks are dumped:
5384 if (state_filter
== -1)
5385 debug_show_all_locks();
5388 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5390 idle
->sched_class
= &idle_sched_class
;
5394 * init_idle - set up an idle thread for a given CPU
5395 * @idle: task in question
5396 * @cpu: cpu the idle task belongs to
5398 * NOTE: this function does not set the idle thread's NEED_RESCHED
5399 * flag, to make booting more robust.
5401 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5403 struct rq
*rq
= cpu_rq(cpu
);
5404 unsigned long flags
;
5407 idle
->se
.exec_start
= sched_clock();
5409 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
5410 idle
->cpus_allowed
= cpumask_of_cpu(cpu
);
5411 __set_task_cpu(idle
, cpu
);
5413 spin_lock_irqsave(&rq
->lock
, flags
);
5414 rq
->curr
= rq
->idle
= idle
;
5415 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5418 spin_unlock_irqrestore(&rq
->lock
, flags
);
5420 /* Set the preempt count _outside_ the spinlocks! */
5421 task_thread_info(idle
)->preempt_count
= 0;
5424 * The idle tasks have their own, simple scheduling class:
5426 idle
->sched_class
= &idle_sched_class
;
5430 * In a system that switches off the HZ timer nohz_cpu_mask
5431 * indicates which cpus entered this state. This is used
5432 * in the rcu update to wait only for active cpus. For system
5433 * which do not switch off the HZ timer nohz_cpu_mask should
5434 * always be CPU_MASK_NONE.
5436 cpumask_t nohz_cpu_mask
= CPU_MASK_NONE
;
5439 * Increase the granularity value when there are more CPUs,
5440 * because with more CPUs the 'effective latency' as visible
5441 * to users decreases. But the relationship is not linear,
5442 * so pick a second-best guess by going with the log2 of the
5445 * This idea comes from the SD scheduler of Con Kolivas:
5447 static inline void sched_init_granularity(void)
5449 unsigned int factor
= 1 + ilog2(num_online_cpus());
5450 const unsigned long limit
= 200000000;
5452 sysctl_sched_min_granularity
*= factor
;
5453 if (sysctl_sched_min_granularity
> limit
)
5454 sysctl_sched_min_granularity
= limit
;
5456 sysctl_sched_latency
*= factor
;
5457 if (sysctl_sched_latency
> limit
)
5458 sysctl_sched_latency
= limit
;
5460 sysctl_sched_wakeup_granularity
*= factor
;
5465 * This is how migration works:
5467 * 1) we queue a struct migration_req structure in the source CPU's
5468 * runqueue and wake up that CPU's migration thread.
5469 * 2) we down() the locked semaphore => thread blocks.
5470 * 3) migration thread wakes up (implicitly it forces the migrated
5471 * thread off the CPU)
5472 * 4) it gets the migration request and checks whether the migrated
5473 * task is still in the wrong runqueue.
5474 * 5) if it's in the wrong runqueue then the migration thread removes
5475 * it and puts it into the right queue.
5476 * 6) migration thread up()s the semaphore.
5477 * 7) we wake up and the migration is done.
5481 * Change a given task's CPU affinity. Migrate the thread to a
5482 * proper CPU and schedule it away if the CPU it's executing on
5483 * is removed from the allowed bitmask.
5485 * NOTE: the caller must have a valid reference to the task, the
5486 * task must not exit() & deallocate itself prematurely. The
5487 * call is not atomic; no spinlocks may be held.
5489 int set_cpus_allowed(struct task_struct
*p
, cpumask_t new_mask
)
5491 struct migration_req req
;
5492 unsigned long flags
;
5496 rq
= task_rq_lock(p
, &flags
);
5497 if (!cpus_intersects(new_mask
, cpu_online_map
)) {
5502 if (p
->sched_class
->set_cpus_allowed
)
5503 p
->sched_class
->set_cpus_allowed(p
, &new_mask
);
5505 p
->cpus_allowed
= new_mask
;
5506 p
->rt
.nr_cpus_allowed
= cpus_weight(new_mask
);
5509 /* Can the task run on the task's current CPU? If so, we're done */
5510 if (cpu_isset(task_cpu(p
), new_mask
))
5513 if (migrate_task(p
, any_online_cpu(new_mask
), &req
)) {
5514 /* Need help from migration thread: drop lock and wait. */
5515 task_rq_unlock(rq
, &flags
);
5516 wake_up_process(rq
->migration_thread
);
5517 wait_for_completion(&req
.done
);
5518 tlb_migrate_finish(p
->mm
);
5522 task_rq_unlock(rq
, &flags
);
5526 EXPORT_SYMBOL_GPL(set_cpus_allowed
);
5529 * Move (not current) task off this cpu, onto dest cpu. We're doing
5530 * this because either it can't run here any more (set_cpus_allowed()
5531 * away from this CPU, or CPU going down), or because we're
5532 * attempting to rebalance this task on exec (sched_exec).
5534 * So we race with normal scheduler movements, but that's OK, as long
5535 * as the task is no longer on this CPU.
5537 * Returns non-zero if task was successfully migrated.
5539 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5541 struct rq
*rq_dest
, *rq_src
;
5544 if (unlikely(cpu_is_offline(dest_cpu
)))
5547 rq_src
= cpu_rq(src_cpu
);
5548 rq_dest
= cpu_rq(dest_cpu
);
5550 double_rq_lock(rq_src
, rq_dest
);
5551 /* Already moved. */
5552 if (task_cpu(p
) != src_cpu
)
5554 /* Affinity changed (again). */
5555 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
))
5558 on_rq
= p
->se
.on_rq
;
5560 deactivate_task(rq_src
, p
, 0);
5562 set_task_cpu(p
, dest_cpu
);
5564 activate_task(rq_dest
, p
, 0);
5565 check_preempt_curr(rq_dest
, p
);
5569 double_rq_unlock(rq_src
, rq_dest
);
5574 * migration_thread - this is a highprio system thread that performs
5575 * thread migration by bumping thread off CPU then 'pushing' onto
5578 static int migration_thread(void *data
)
5580 int cpu
= (long)data
;
5584 BUG_ON(rq
->migration_thread
!= current
);
5586 set_current_state(TASK_INTERRUPTIBLE
);
5587 while (!kthread_should_stop()) {
5588 struct migration_req
*req
;
5589 struct list_head
*head
;
5591 spin_lock_irq(&rq
->lock
);
5593 if (cpu_is_offline(cpu
)) {
5594 spin_unlock_irq(&rq
->lock
);
5598 if (rq
->active_balance
) {
5599 active_load_balance(rq
, cpu
);
5600 rq
->active_balance
= 0;
5603 head
= &rq
->migration_queue
;
5605 if (list_empty(head
)) {
5606 spin_unlock_irq(&rq
->lock
);
5608 set_current_state(TASK_INTERRUPTIBLE
);
5611 req
= list_entry(head
->next
, struct migration_req
, list
);
5612 list_del_init(head
->next
);
5614 spin_unlock(&rq
->lock
);
5615 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
5618 complete(&req
->done
);
5620 __set_current_state(TASK_RUNNING
);
5624 /* Wait for kthread_stop */
5625 set_current_state(TASK_INTERRUPTIBLE
);
5626 while (!kthread_should_stop()) {
5628 set_current_state(TASK_INTERRUPTIBLE
);
5630 __set_current_state(TASK_RUNNING
);
5634 #ifdef CONFIG_HOTPLUG_CPU
5636 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5640 local_irq_disable();
5641 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
5647 * Figure out where task on dead CPU should go, use force if necessary.
5648 * NOTE: interrupts should be disabled by the caller
5650 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5652 unsigned long flags
;
5659 mask
= node_to_cpumask(cpu_to_node(dead_cpu
));
5660 cpus_and(mask
, mask
, p
->cpus_allowed
);
5661 dest_cpu
= any_online_cpu(mask
);
5663 /* On any allowed CPU? */
5664 if (dest_cpu
>= nr_cpu_ids
)
5665 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5667 /* No more Mr. Nice Guy. */
5668 if (dest_cpu
>= nr_cpu_ids
) {
5669 cpumask_t cpus_allowed
;
5671 cpuset_cpus_allowed_locked(p
, &cpus_allowed
);
5673 * Try to stay on the same cpuset, where the
5674 * current cpuset may be a subset of all cpus.
5675 * The cpuset_cpus_allowed_locked() variant of
5676 * cpuset_cpus_allowed() will not block. It must be
5677 * called within calls to cpuset_lock/cpuset_unlock.
5679 rq
= task_rq_lock(p
, &flags
);
5680 p
->cpus_allowed
= cpus_allowed
;
5681 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5682 task_rq_unlock(rq
, &flags
);
5685 * Don't tell them about moving exiting tasks or
5686 * kernel threads (both mm NULL), since they never
5689 if (p
->mm
&& printk_ratelimit()) {
5690 printk(KERN_INFO
"process %d (%s) no "
5691 "longer affine to cpu%d\n",
5692 task_pid_nr(p
), p
->comm
, dead_cpu
);
5695 } while (!__migrate_task_irq(p
, dead_cpu
, dest_cpu
));
5699 * While a dead CPU has no uninterruptible tasks queued at this point,
5700 * it might still have a nonzero ->nr_uninterruptible counter, because
5701 * for performance reasons the counter is not stricly tracking tasks to
5702 * their home CPUs. So we just add the counter to another CPU's counter,
5703 * to keep the global sum constant after CPU-down:
5705 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5707 struct rq
*rq_dest
= cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR
));
5708 unsigned long flags
;
5710 local_irq_save(flags
);
5711 double_rq_lock(rq_src
, rq_dest
);
5712 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5713 rq_src
->nr_uninterruptible
= 0;
5714 double_rq_unlock(rq_src
, rq_dest
);
5715 local_irq_restore(flags
);
5718 /* Run through task list and migrate tasks from the dead cpu. */
5719 static void migrate_live_tasks(int src_cpu
)
5721 struct task_struct
*p
, *t
;
5723 read_lock(&tasklist_lock
);
5725 do_each_thread(t
, p
) {
5729 if (task_cpu(p
) == src_cpu
)
5730 move_task_off_dead_cpu(src_cpu
, p
);
5731 } while_each_thread(t
, p
);
5733 read_unlock(&tasklist_lock
);
5737 * Schedules idle task to be the next runnable task on current CPU.
5738 * It does so by boosting its priority to highest possible.
5739 * Used by CPU offline code.
5741 void sched_idle_next(void)
5743 int this_cpu
= smp_processor_id();
5744 struct rq
*rq
= cpu_rq(this_cpu
);
5745 struct task_struct
*p
= rq
->idle
;
5746 unsigned long flags
;
5748 /* cpu has to be offline */
5749 BUG_ON(cpu_online(this_cpu
));
5752 * Strictly not necessary since rest of the CPUs are stopped by now
5753 * and interrupts disabled on the current cpu.
5755 spin_lock_irqsave(&rq
->lock
, flags
);
5757 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5759 update_rq_clock(rq
);
5760 activate_task(rq
, p
, 0);
5762 spin_unlock_irqrestore(&rq
->lock
, flags
);
5766 * Ensures that the idle task is using init_mm right before its cpu goes
5769 void idle_task_exit(void)
5771 struct mm_struct
*mm
= current
->active_mm
;
5773 BUG_ON(cpu_online(smp_processor_id()));
5776 switch_mm(mm
, &init_mm
, current
);
5780 /* called under rq->lock with disabled interrupts */
5781 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5783 struct rq
*rq
= cpu_rq(dead_cpu
);
5785 /* Must be exiting, otherwise would be on tasklist. */
5786 BUG_ON(!p
->exit_state
);
5788 /* Cannot have done final schedule yet: would have vanished. */
5789 BUG_ON(p
->state
== TASK_DEAD
);
5794 * Drop lock around migration; if someone else moves it,
5795 * that's OK. No task can be added to this CPU, so iteration is
5798 spin_unlock_irq(&rq
->lock
);
5799 move_task_off_dead_cpu(dead_cpu
, p
);
5800 spin_lock_irq(&rq
->lock
);
5805 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5806 static void migrate_dead_tasks(unsigned int dead_cpu
)
5808 struct rq
*rq
= cpu_rq(dead_cpu
);
5809 struct task_struct
*next
;
5812 if (!rq
->nr_running
)
5814 update_rq_clock(rq
);
5815 next
= pick_next_task(rq
, rq
->curr
);
5818 migrate_dead(dead_cpu
, next
);
5822 #endif /* CONFIG_HOTPLUG_CPU */
5824 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5826 static struct ctl_table sd_ctl_dir
[] = {
5828 .procname
= "sched_domain",
5834 static struct ctl_table sd_ctl_root
[] = {
5836 .ctl_name
= CTL_KERN
,
5837 .procname
= "kernel",
5839 .child
= sd_ctl_dir
,
5844 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5846 struct ctl_table
*entry
=
5847 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5852 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5854 struct ctl_table
*entry
;
5857 * In the intermediate directories, both the child directory and
5858 * procname are dynamically allocated and could fail but the mode
5859 * will always be set. In the lowest directory the names are
5860 * static strings and all have proc handlers.
5862 for (entry
= *tablep
; entry
->mode
; entry
++) {
5864 sd_free_ctl_entry(&entry
->child
);
5865 if (entry
->proc_handler
== NULL
)
5866 kfree(entry
->procname
);
5874 set_table_entry(struct ctl_table
*entry
,
5875 const char *procname
, void *data
, int maxlen
,
5876 mode_t mode
, proc_handler
*proc_handler
)
5878 entry
->procname
= procname
;
5880 entry
->maxlen
= maxlen
;
5882 entry
->proc_handler
= proc_handler
;
5885 static struct ctl_table
*
5886 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5888 struct ctl_table
*table
= sd_alloc_ctl_entry(12);
5893 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5894 sizeof(long), 0644, proc_doulongvec_minmax
);
5895 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5896 sizeof(long), 0644, proc_doulongvec_minmax
);
5897 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5898 sizeof(int), 0644, proc_dointvec_minmax
);
5899 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5900 sizeof(int), 0644, proc_dointvec_minmax
);
5901 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5902 sizeof(int), 0644, proc_dointvec_minmax
);
5903 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5904 sizeof(int), 0644, proc_dointvec_minmax
);
5905 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5906 sizeof(int), 0644, proc_dointvec_minmax
);
5907 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5908 sizeof(int), 0644, proc_dointvec_minmax
);
5909 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5910 sizeof(int), 0644, proc_dointvec_minmax
);
5911 set_table_entry(&table
[9], "cache_nice_tries",
5912 &sd
->cache_nice_tries
,
5913 sizeof(int), 0644, proc_dointvec_minmax
);
5914 set_table_entry(&table
[10], "flags", &sd
->flags
,
5915 sizeof(int), 0644, proc_dointvec_minmax
);
5916 /* &table[11] is terminator */
5921 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5923 struct ctl_table
*entry
, *table
;
5924 struct sched_domain
*sd
;
5925 int domain_num
= 0, i
;
5928 for_each_domain(cpu
, sd
)
5930 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5935 for_each_domain(cpu
, sd
) {
5936 snprintf(buf
, 32, "domain%d", i
);
5937 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5939 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5946 static struct ctl_table_header
*sd_sysctl_header
;
5947 static void register_sched_domain_sysctl(void)
5949 int i
, cpu_num
= num_online_cpus();
5950 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5953 WARN_ON(sd_ctl_dir
[0].child
);
5954 sd_ctl_dir
[0].child
= entry
;
5959 for_each_online_cpu(i
) {
5960 snprintf(buf
, 32, "cpu%d", i
);
5961 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5963 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5967 WARN_ON(sd_sysctl_header
);
5968 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5971 /* may be called multiple times per register */
5972 static void unregister_sched_domain_sysctl(void)
5974 if (sd_sysctl_header
)
5975 unregister_sysctl_table(sd_sysctl_header
);
5976 sd_sysctl_header
= NULL
;
5977 if (sd_ctl_dir
[0].child
)
5978 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5981 static void register_sched_domain_sysctl(void)
5984 static void unregister_sched_domain_sysctl(void)
5990 * migration_call - callback that gets triggered when a CPU is added.
5991 * Here we can start up the necessary migration thread for the new CPU.
5993 static int __cpuinit
5994 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5996 struct task_struct
*p
;
5997 int cpu
= (long)hcpu
;
5998 unsigned long flags
;
6003 case CPU_UP_PREPARE
:
6004 case CPU_UP_PREPARE_FROZEN
:
6005 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6008 kthread_bind(p
, cpu
);
6009 /* Must be high prio: stop_machine expects to yield to it. */
6010 rq
= task_rq_lock(p
, &flags
);
6011 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6012 task_rq_unlock(rq
, &flags
);
6013 cpu_rq(cpu
)->migration_thread
= p
;
6017 case CPU_ONLINE_FROZEN
:
6018 /* Strictly unnecessary, as first user will wake it. */
6019 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6021 /* Update our root-domain */
6023 spin_lock_irqsave(&rq
->lock
, flags
);
6025 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6026 cpu_set(cpu
, rq
->rd
->online
);
6028 spin_unlock_irqrestore(&rq
->lock
, flags
);
6031 #ifdef CONFIG_HOTPLUG_CPU
6032 case CPU_UP_CANCELED
:
6033 case CPU_UP_CANCELED_FROZEN
:
6034 if (!cpu_rq(cpu
)->migration_thread
)
6036 /* Unbind it from offline cpu so it can run. Fall thru. */
6037 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6038 any_online_cpu(cpu_online_map
));
6039 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6040 cpu_rq(cpu
)->migration_thread
= NULL
;
6044 case CPU_DEAD_FROZEN
:
6045 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6046 migrate_live_tasks(cpu
);
6048 kthread_stop(rq
->migration_thread
);
6049 rq
->migration_thread
= NULL
;
6050 /* Idle task back to normal (off runqueue, low prio) */
6051 spin_lock_irq(&rq
->lock
);
6052 update_rq_clock(rq
);
6053 deactivate_task(rq
, rq
->idle
, 0);
6054 rq
->idle
->static_prio
= MAX_PRIO
;
6055 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6056 rq
->idle
->sched_class
= &idle_sched_class
;
6057 migrate_dead_tasks(cpu
);
6058 spin_unlock_irq(&rq
->lock
);
6060 migrate_nr_uninterruptible(rq
);
6061 BUG_ON(rq
->nr_running
!= 0);
6064 * No need to migrate the tasks: it was best-effort if
6065 * they didn't take sched_hotcpu_mutex. Just wake up
6068 spin_lock_irq(&rq
->lock
);
6069 while (!list_empty(&rq
->migration_queue
)) {
6070 struct migration_req
*req
;
6072 req
= list_entry(rq
->migration_queue
.next
,
6073 struct migration_req
, list
);
6074 list_del_init(&req
->list
);
6075 complete(&req
->done
);
6077 spin_unlock_irq(&rq
->lock
);
6081 case CPU_DYING_FROZEN
:
6082 /* Update our root-domain */
6084 spin_lock_irqsave(&rq
->lock
, flags
);
6086 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6087 cpu_clear(cpu
, rq
->rd
->online
);
6089 spin_unlock_irqrestore(&rq
->lock
, flags
);
6096 /* Register at highest priority so that task migration (migrate_all_tasks)
6097 * happens before everything else.
6099 static struct notifier_block __cpuinitdata migration_notifier
= {
6100 .notifier_call
= migration_call
,
6104 void __init
migration_init(void)
6106 void *cpu
= (void *)(long)smp_processor_id();
6109 /* Start one for the boot CPU: */
6110 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6111 BUG_ON(err
== NOTIFY_BAD
);
6112 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6113 register_cpu_notifier(&migration_notifier
);
6119 /* Number of possible processor ids */
6120 int nr_cpu_ids __read_mostly
= NR_CPUS
;
6121 EXPORT_SYMBOL(nr_cpu_ids
);
6123 #ifdef CONFIG_SCHED_DEBUG
6125 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6126 cpumask_t
*groupmask
)
6128 struct sched_group
*group
= sd
->groups
;
6131 cpulist_scnprintf(str
, sizeof(str
), sd
->span
);
6132 cpus_clear(*groupmask
);
6134 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6136 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6137 printk("does not load-balance\n");
6139 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6144 printk(KERN_CONT
"span %s\n", str
);
6146 if (!cpu_isset(cpu
, sd
->span
)) {
6147 printk(KERN_ERR
"ERROR: domain->span does not contain "
6150 if (!cpu_isset(cpu
, group
->cpumask
)) {
6151 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6155 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6159 printk(KERN_ERR
"ERROR: group is NULL\n");
6163 if (!group
->__cpu_power
) {
6164 printk(KERN_CONT
"\n");
6165 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6170 if (!cpus_weight(group
->cpumask
)) {
6171 printk(KERN_CONT
"\n");
6172 printk(KERN_ERR
"ERROR: empty group\n");
6176 if (cpus_intersects(*groupmask
, group
->cpumask
)) {
6177 printk(KERN_CONT
"\n");
6178 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6182 cpus_or(*groupmask
, *groupmask
, group
->cpumask
);
6184 cpulist_scnprintf(str
, sizeof(str
), group
->cpumask
);
6185 printk(KERN_CONT
" %s", str
);
6187 group
= group
->next
;
6188 } while (group
!= sd
->groups
);
6189 printk(KERN_CONT
"\n");
6191 if (!cpus_equal(sd
->span
, *groupmask
))
6192 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6194 if (sd
->parent
&& !cpus_subset(*groupmask
, sd
->parent
->span
))
6195 printk(KERN_ERR
"ERROR: parent span is not a superset "
6196 "of domain->span\n");
6200 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6202 cpumask_t
*groupmask
;
6206 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6210 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6212 groupmask
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
6214 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6219 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6229 # define sched_domain_debug(sd, cpu) do { } while (0)
6232 static int sd_degenerate(struct sched_domain
*sd
)
6234 if (cpus_weight(sd
->span
) == 1)
6237 /* Following flags need at least 2 groups */
6238 if (sd
->flags
& (SD_LOAD_BALANCE
|
6239 SD_BALANCE_NEWIDLE
|
6243 SD_SHARE_PKG_RESOURCES
)) {
6244 if (sd
->groups
!= sd
->groups
->next
)
6248 /* Following flags don't use groups */
6249 if (sd
->flags
& (SD_WAKE_IDLE
|
6258 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6260 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6262 if (sd_degenerate(parent
))
6265 if (!cpus_equal(sd
->span
, parent
->span
))
6268 /* Does parent contain flags not in child? */
6269 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6270 if (cflags
& SD_WAKE_AFFINE
)
6271 pflags
&= ~SD_WAKE_BALANCE
;
6272 /* Flags needing groups don't count if only 1 group in parent */
6273 if (parent
->groups
== parent
->groups
->next
) {
6274 pflags
&= ~(SD_LOAD_BALANCE
|
6275 SD_BALANCE_NEWIDLE
|
6279 SD_SHARE_PKG_RESOURCES
);
6281 if (~cflags
& pflags
)
6287 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6289 unsigned long flags
;
6290 const struct sched_class
*class;
6292 spin_lock_irqsave(&rq
->lock
, flags
);
6295 struct root_domain
*old_rd
= rq
->rd
;
6297 for (class = sched_class_highest
; class; class = class->next
) {
6298 if (class->leave_domain
)
6299 class->leave_domain(rq
);
6302 cpu_clear(rq
->cpu
, old_rd
->span
);
6303 cpu_clear(rq
->cpu
, old_rd
->online
);
6305 if (atomic_dec_and_test(&old_rd
->refcount
))
6309 atomic_inc(&rd
->refcount
);
6312 cpu_set(rq
->cpu
, rd
->span
);
6313 if (cpu_isset(rq
->cpu
, cpu_online_map
))
6314 cpu_set(rq
->cpu
, rd
->online
);
6316 for (class = sched_class_highest
; class; class = class->next
) {
6317 if (class->join_domain
)
6318 class->join_domain(rq
);
6321 spin_unlock_irqrestore(&rq
->lock
, flags
);
6324 static void init_rootdomain(struct root_domain
*rd
)
6326 memset(rd
, 0, sizeof(*rd
));
6328 cpus_clear(rd
->span
);
6329 cpus_clear(rd
->online
);
6332 static void init_defrootdomain(void)
6334 init_rootdomain(&def_root_domain
);
6335 atomic_set(&def_root_domain
.refcount
, 1);
6338 static struct root_domain
*alloc_rootdomain(void)
6340 struct root_domain
*rd
;
6342 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6346 init_rootdomain(rd
);
6352 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6353 * hold the hotplug lock.
6356 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6358 struct rq
*rq
= cpu_rq(cpu
);
6359 struct sched_domain
*tmp
;
6361 /* Remove the sched domains which do not contribute to scheduling. */
6362 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
) {
6363 struct sched_domain
*parent
= tmp
->parent
;
6366 if (sd_parent_degenerate(tmp
, parent
)) {
6367 tmp
->parent
= parent
->parent
;
6369 parent
->parent
->child
= tmp
;
6373 if (sd
&& sd_degenerate(sd
)) {
6379 sched_domain_debug(sd
, cpu
);
6381 rq_attach_root(rq
, rd
);
6382 rcu_assign_pointer(rq
->sd
, sd
);
6385 /* cpus with isolated domains */
6386 static cpumask_t cpu_isolated_map
= CPU_MASK_NONE
;
6388 /* Setup the mask of cpus configured for isolated domains */
6389 static int __init
isolated_cpu_setup(char *str
)
6391 int ints
[NR_CPUS
], i
;
6393 str
= get_options(str
, ARRAY_SIZE(ints
), ints
);
6394 cpus_clear(cpu_isolated_map
);
6395 for (i
= 1; i
<= ints
[0]; i
++)
6396 if (ints
[i
] < NR_CPUS
)
6397 cpu_set(ints
[i
], cpu_isolated_map
);
6401 __setup("isolcpus=", isolated_cpu_setup
);
6404 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6405 * to a function which identifies what group(along with sched group) a CPU
6406 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6407 * (due to the fact that we keep track of groups covered with a cpumask_t).
6409 * init_sched_build_groups will build a circular linked list of the groups
6410 * covered by the given span, and will set each group's ->cpumask correctly,
6411 * and ->cpu_power to 0.
6414 init_sched_build_groups(const cpumask_t
*span
, const cpumask_t
*cpu_map
,
6415 int (*group_fn
)(int cpu
, const cpumask_t
*cpu_map
,
6416 struct sched_group
**sg
,
6417 cpumask_t
*tmpmask
),
6418 cpumask_t
*covered
, cpumask_t
*tmpmask
)
6420 struct sched_group
*first
= NULL
, *last
= NULL
;
6423 cpus_clear(*covered
);
6425 for_each_cpu_mask(i
, *span
) {
6426 struct sched_group
*sg
;
6427 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6430 if (cpu_isset(i
, *covered
))
6433 cpus_clear(sg
->cpumask
);
6434 sg
->__cpu_power
= 0;
6436 for_each_cpu_mask(j
, *span
) {
6437 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6440 cpu_set(j
, *covered
);
6441 cpu_set(j
, sg
->cpumask
);
6452 #define SD_NODES_PER_DOMAIN 16
6457 * find_next_best_node - find the next node to include in a sched_domain
6458 * @node: node whose sched_domain we're building
6459 * @used_nodes: nodes already in the sched_domain
6461 * Find the next node to include in a given scheduling domain. Simply
6462 * finds the closest node not already in the @used_nodes map.
6464 * Should use nodemask_t.
6466 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6468 int i
, n
, val
, min_val
, best_node
= 0;
6472 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6473 /* Start at @node */
6474 n
= (node
+ i
) % MAX_NUMNODES
;
6476 if (!nr_cpus_node(n
))
6479 /* Skip already used nodes */
6480 if (node_isset(n
, *used_nodes
))
6483 /* Simple min distance search */
6484 val
= node_distance(node
, n
);
6486 if (val
< min_val
) {
6492 node_set(best_node
, *used_nodes
);
6497 * sched_domain_node_span - get a cpumask for a node's sched_domain
6498 * @node: node whose cpumask we're constructing
6500 * Given a node, construct a good cpumask for its sched_domain to span. It
6501 * should be one that prevents unnecessary balancing, but also spreads tasks
6504 static void sched_domain_node_span(int node
, cpumask_t
*span
)
6506 nodemask_t used_nodes
;
6507 node_to_cpumask_ptr(nodemask
, node
);
6511 nodes_clear(used_nodes
);
6513 cpus_or(*span
, *span
, *nodemask
);
6514 node_set(node
, used_nodes
);
6516 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6517 int next_node
= find_next_best_node(node
, &used_nodes
);
6519 node_to_cpumask_ptr_next(nodemask
, next_node
);
6520 cpus_or(*span
, *span
, *nodemask
);
6525 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6528 * SMT sched-domains:
6530 #ifdef CONFIG_SCHED_SMT
6531 static DEFINE_PER_CPU(struct sched_domain
, cpu_domains
);
6532 static DEFINE_PER_CPU(struct sched_group
, sched_group_cpus
);
6535 cpu_to_cpu_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6539 *sg
= &per_cpu(sched_group_cpus
, cpu
);
6545 * multi-core sched-domains:
6547 #ifdef CONFIG_SCHED_MC
6548 static DEFINE_PER_CPU(struct sched_domain
, core_domains
);
6549 static DEFINE_PER_CPU(struct sched_group
, sched_group_core
);
6552 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6554 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6559 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6560 cpus_and(*mask
, *mask
, *cpu_map
);
6561 group
= first_cpu(*mask
);
6563 *sg
= &per_cpu(sched_group_core
, group
);
6566 #elif defined(CONFIG_SCHED_MC)
6568 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6572 *sg
= &per_cpu(sched_group_core
, cpu
);
6577 static DEFINE_PER_CPU(struct sched_domain
, phys_domains
);
6578 static DEFINE_PER_CPU(struct sched_group
, sched_group_phys
);
6581 cpu_to_phys_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6585 #ifdef CONFIG_SCHED_MC
6586 *mask
= cpu_coregroup_map(cpu
);
6587 cpus_and(*mask
, *mask
, *cpu_map
);
6588 group
= first_cpu(*mask
);
6589 #elif defined(CONFIG_SCHED_SMT)
6590 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6591 cpus_and(*mask
, *mask
, *cpu_map
);
6592 group
= first_cpu(*mask
);
6597 *sg
= &per_cpu(sched_group_phys
, group
);
6603 * The init_sched_build_groups can't handle what we want to do with node
6604 * groups, so roll our own. Now each node has its own list of groups which
6605 * gets dynamically allocated.
6607 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
6608 static struct sched_group
***sched_group_nodes_bycpu
;
6610 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
6611 static DEFINE_PER_CPU(struct sched_group
, sched_group_allnodes
);
6613 static int cpu_to_allnodes_group(int cpu
, const cpumask_t
*cpu_map
,
6614 struct sched_group
**sg
, cpumask_t
*nodemask
)
6618 *nodemask
= node_to_cpumask(cpu_to_node(cpu
));
6619 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6620 group
= first_cpu(*nodemask
);
6623 *sg
= &per_cpu(sched_group_allnodes
, group
);
6627 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6629 struct sched_group
*sg
= group_head
;
6635 for_each_cpu_mask(j
, sg
->cpumask
) {
6636 struct sched_domain
*sd
;
6638 sd
= &per_cpu(phys_domains
, j
);
6639 if (j
!= first_cpu(sd
->groups
->cpumask
)) {
6641 * Only add "power" once for each
6647 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
6650 } while (sg
!= group_head
);
6655 /* Free memory allocated for various sched_group structures */
6656 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6660 for_each_cpu_mask(cpu
, *cpu_map
) {
6661 struct sched_group
**sched_group_nodes
6662 = sched_group_nodes_bycpu
[cpu
];
6664 if (!sched_group_nodes
)
6667 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6668 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6670 *nodemask
= node_to_cpumask(i
);
6671 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6672 if (cpus_empty(*nodemask
))
6682 if (oldsg
!= sched_group_nodes
[i
])
6685 kfree(sched_group_nodes
);
6686 sched_group_nodes_bycpu
[cpu
] = NULL
;
6690 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6696 * Initialize sched groups cpu_power.
6698 * cpu_power indicates the capacity of sched group, which is used while
6699 * distributing the load between different sched groups in a sched domain.
6700 * Typically cpu_power for all the groups in a sched domain will be same unless
6701 * there are asymmetries in the topology. If there are asymmetries, group
6702 * having more cpu_power will pickup more load compared to the group having
6705 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6706 * the maximum number of tasks a group can handle in the presence of other idle
6707 * or lightly loaded groups in the same sched domain.
6709 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6711 struct sched_domain
*child
;
6712 struct sched_group
*group
;
6714 WARN_ON(!sd
|| !sd
->groups
);
6716 if (cpu
!= first_cpu(sd
->groups
->cpumask
))
6721 sd
->groups
->__cpu_power
= 0;
6724 * For perf policy, if the groups in child domain share resources
6725 * (for example cores sharing some portions of the cache hierarchy
6726 * or SMT), then set this domain groups cpu_power such that each group
6727 * can handle only one task, when there are other idle groups in the
6728 * same sched domain.
6730 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
6732 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
6733 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
6738 * add cpu_power of each child group to this groups cpu_power
6740 group
= child
->groups
;
6742 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
6743 group
= group
->next
;
6744 } while (group
!= child
->groups
);
6748 * Initializers for schedule domains
6749 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6752 #define SD_INIT(sd, type) sd_init_##type(sd)
6753 #define SD_INIT_FUNC(type) \
6754 static noinline void sd_init_##type(struct sched_domain *sd) \
6756 memset(sd, 0, sizeof(*sd)); \
6757 *sd = SD_##type##_INIT; \
6762 SD_INIT_FUNC(ALLNODES
)
6765 #ifdef CONFIG_SCHED_SMT
6766 SD_INIT_FUNC(SIBLING
)
6768 #ifdef CONFIG_SCHED_MC
6773 * To minimize stack usage kmalloc room for cpumasks and share the
6774 * space as the usage in build_sched_domains() dictates. Used only
6775 * if the amount of space is significant.
6778 cpumask_t tmpmask
; /* make this one first */
6781 cpumask_t this_sibling_map
;
6782 cpumask_t this_core_map
;
6784 cpumask_t send_covered
;
6787 cpumask_t domainspan
;
6789 cpumask_t notcovered
;
6794 #define SCHED_CPUMASK_ALLOC 1
6795 #define SCHED_CPUMASK_FREE(v) kfree(v)
6796 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
6798 #define SCHED_CPUMASK_ALLOC 0
6799 #define SCHED_CPUMASK_FREE(v)
6800 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
6803 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
6804 ((unsigned long)(a) + offsetof(struct allmasks, v))
6807 * Build sched domains for a given set of cpus and attach the sched domains
6808 * to the individual cpus
6810 static int build_sched_domains(const cpumask_t
*cpu_map
)
6813 struct root_domain
*rd
;
6814 SCHED_CPUMASK_DECLARE(allmasks
);
6817 struct sched_group
**sched_group_nodes
= NULL
;
6818 int sd_allnodes
= 0;
6821 * Allocate the per-node list of sched groups
6823 sched_group_nodes
= kcalloc(MAX_NUMNODES
, sizeof(struct sched_group
*),
6825 if (!sched_group_nodes
) {
6826 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6831 rd
= alloc_rootdomain();
6833 printk(KERN_WARNING
"Cannot alloc root domain\n");
6835 kfree(sched_group_nodes
);
6840 #if SCHED_CPUMASK_ALLOC
6841 /* get space for all scratch cpumask variables */
6842 allmasks
= kmalloc(sizeof(*allmasks
), GFP_KERNEL
);
6844 printk(KERN_WARNING
"Cannot alloc cpumask array\n");
6847 kfree(sched_group_nodes
);
6852 tmpmask
= (cpumask_t
*)allmasks
;
6856 sched_group_nodes_bycpu
[first_cpu(*cpu_map
)] = sched_group_nodes
;
6860 * Set up domains for cpus specified by the cpu_map.
6862 for_each_cpu_mask(i
, *cpu_map
) {
6863 struct sched_domain
*sd
= NULL
, *p
;
6864 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6866 *nodemask
= node_to_cpumask(cpu_to_node(i
));
6867 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6870 if (cpus_weight(*cpu_map
) >
6871 SD_NODES_PER_DOMAIN
*cpus_weight(*nodemask
)) {
6872 sd
= &per_cpu(allnodes_domains
, i
);
6873 SD_INIT(sd
, ALLNODES
);
6874 sd
->span
= *cpu_map
;
6875 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6881 sd
= &per_cpu(node_domains
, i
);
6883 sched_domain_node_span(cpu_to_node(i
), &sd
->span
);
6887 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6891 sd
= &per_cpu(phys_domains
, i
);
6893 sd
->span
= *nodemask
;
6897 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6899 #ifdef CONFIG_SCHED_MC
6901 sd
= &per_cpu(core_domains
, i
);
6903 sd
->span
= cpu_coregroup_map(i
);
6904 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6907 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6910 #ifdef CONFIG_SCHED_SMT
6912 sd
= &per_cpu(cpu_domains
, i
);
6913 SD_INIT(sd
, SIBLING
);
6914 sd
->span
= per_cpu(cpu_sibling_map
, i
);
6915 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
6918 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6922 #ifdef CONFIG_SCHED_SMT
6923 /* Set up CPU (sibling) groups */
6924 for_each_cpu_mask(i
, *cpu_map
) {
6925 SCHED_CPUMASK_VAR(this_sibling_map
, allmasks
);
6926 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6928 *this_sibling_map
= per_cpu(cpu_sibling_map
, i
);
6929 cpus_and(*this_sibling_map
, *this_sibling_map
, *cpu_map
);
6930 if (i
!= first_cpu(*this_sibling_map
))
6933 init_sched_build_groups(this_sibling_map
, cpu_map
,
6935 send_covered
, tmpmask
);
6939 #ifdef CONFIG_SCHED_MC
6940 /* Set up multi-core groups */
6941 for_each_cpu_mask(i
, *cpu_map
) {
6942 SCHED_CPUMASK_VAR(this_core_map
, allmasks
);
6943 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6945 *this_core_map
= cpu_coregroup_map(i
);
6946 cpus_and(*this_core_map
, *this_core_map
, *cpu_map
);
6947 if (i
!= first_cpu(*this_core_map
))
6950 init_sched_build_groups(this_core_map
, cpu_map
,
6952 send_covered
, tmpmask
);
6956 /* Set up physical groups */
6957 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6958 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6959 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6961 *nodemask
= node_to_cpumask(i
);
6962 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6963 if (cpus_empty(*nodemask
))
6966 init_sched_build_groups(nodemask
, cpu_map
,
6968 send_covered
, tmpmask
);
6972 /* Set up node groups */
6974 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
6976 init_sched_build_groups(cpu_map
, cpu_map
,
6977 &cpu_to_allnodes_group
,
6978 send_covered
, tmpmask
);
6981 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6982 /* Set up node groups */
6983 struct sched_group
*sg
, *prev
;
6984 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6985 SCHED_CPUMASK_VAR(domainspan
, allmasks
);
6986 SCHED_CPUMASK_VAR(covered
, allmasks
);
6989 *nodemask
= node_to_cpumask(i
);
6990 cpus_clear(*covered
);
6992 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6993 if (cpus_empty(*nodemask
)) {
6994 sched_group_nodes
[i
] = NULL
;
6998 sched_domain_node_span(i
, domainspan
);
6999 cpus_and(*domainspan
, *domainspan
, *cpu_map
);
7001 sg
= kmalloc_node(sizeof(struct sched_group
), GFP_KERNEL
, i
);
7003 printk(KERN_WARNING
"Can not alloc domain group for "
7007 sched_group_nodes
[i
] = sg
;
7008 for_each_cpu_mask(j
, *nodemask
) {
7009 struct sched_domain
*sd
;
7011 sd
= &per_cpu(node_domains
, j
);
7014 sg
->__cpu_power
= 0;
7015 sg
->cpumask
= *nodemask
;
7017 cpus_or(*covered
, *covered
, *nodemask
);
7020 for (j
= 0; j
< MAX_NUMNODES
; j
++) {
7021 SCHED_CPUMASK_VAR(notcovered
, allmasks
);
7022 int n
= (i
+ j
) % MAX_NUMNODES
;
7023 node_to_cpumask_ptr(pnodemask
, n
);
7025 cpus_complement(*notcovered
, *covered
);
7026 cpus_and(*tmpmask
, *notcovered
, *cpu_map
);
7027 cpus_and(*tmpmask
, *tmpmask
, *domainspan
);
7028 if (cpus_empty(*tmpmask
))
7031 cpus_and(*tmpmask
, *tmpmask
, *pnodemask
);
7032 if (cpus_empty(*tmpmask
))
7035 sg
= kmalloc_node(sizeof(struct sched_group
),
7039 "Can not alloc domain group for node %d\n", j
);
7042 sg
->__cpu_power
= 0;
7043 sg
->cpumask
= *tmpmask
;
7044 sg
->next
= prev
->next
;
7045 cpus_or(*covered
, *covered
, *tmpmask
);
7052 /* Calculate CPU power for physical packages and nodes */
7053 #ifdef CONFIG_SCHED_SMT
7054 for_each_cpu_mask(i
, *cpu_map
) {
7055 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
);
7057 init_sched_groups_power(i
, sd
);
7060 #ifdef CONFIG_SCHED_MC
7061 for_each_cpu_mask(i
, *cpu_map
) {
7062 struct sched_domain
*sd
= &per_cpu(core_domains
, i
);
7064 init_sched_groups_power(i
, sd
);
7068 for_each_cpu_mask(i
, *cpu_map
) {
7069 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
);
7071 init_sched_groups_power(i
, sd
);
7075 for (i
= 0; i
< MAX_NUMNODES
; i
++)
7076 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7079 struct sched_group
*sg
;
7081 cpu_to_allnodes_group(first_cpu(*cpu_map
), cpu_map
, &sg
,
7083 init_numa_sched_groups_power(sg
);
7087 /* Attach the domains */
7088 for_each_cpu_mask(i
, *cpu_map
) {
7089 struct sched_domain
*sd
;
7090 #ifdef CONFIG_SCHED_SMT
7091 sd
= &per_cpu(cpu_domains
, i
);
7092 #elif defined(CONFIG_SCHED_MC)
7093 sd
= &per_cpu(core_domains
, i
);
7095 sd
= &per_cpu(phys_domains
, i
);
7097 cpu_attach_domain(sd
, rd
, i
);
7100 SCHED_CPUMASK_FREE((void *)allmasks
);
7105 free_sched_groups(cpu_map
, tmpmask
);
7106 SCHED_CPUMASK_FREE((void *)allmasks
);
7111 static cpumask_t
*doms_cur
; /* current sched domains */
7112 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7115 * Special case: If a kmalloc of a doms_cur partition (array of
7116 * cpumask_t) fails, then fallback to a single sched domain,
7117 * as determined by the single cpumask_t fallback_doms.
7119 static cpumask_t fallback_doms
;
7121 void __attribute__((weak
)) arch_update_cpu_topology(void)
7126 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7127 * For now this just excludes isolated cpus, but could be used to
7128 * exclude other special cases in the future.
7130 static int arch_init_sched_domains(const cpumask_t
*cpu_map
)
7134 arch_update_cpu_topology();
7136 doms_cur
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
7138 doms_cur
= &fallback_doms
;
7139 cpus_andnot(*doms_cur
, *cpu_map
, cpu_isolated_map
);
7140 err
= build_sched_domains(doms_cur
);
7141 register_sched_domain_sysctl();
7146 static void arch_destroy_sched_domains(const cpumask_t
*cpu_map
,
7149 free_sched_groups(cpu_map
, tmpmask
);
7153 * Detach sched domains from a group of cpus specified in cpu_map
7154 * These cpus will now be attached to the NULL domain
7156 static void detach_destroy_domains(const cpumask_t
*cpu_map
)
7161 unregister_sched_domain_sysctl();
7163 for_each_cpu_mask(i
, *cpu_map
)
7164 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7165 synchronize_sched();
7166 arch_destroy_sched_domains(cpu_map
, &tmpmask
);
7170 * Partition sched domains as specified by the 'ndoms_new'
7171 * cpumasks in the array doms_new[] of cpumasks. This compares
7172 * doms_new[] to the current sched domain partitioning, doms_cur[].
7173 * It destroys each deleted domain and builds each new domain.
7175 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7176 * The masks don't intersect (don't overlap.) We should setup one
7177 * sched domain for each mask. CPUs not in any of the cpumasks will
7178 * not be load balanced. If the same cpumask appears both in the
7179 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7182 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7183 * ownership of it and will kfree it when done with it. If the caller
7184 * failed the kmalloc call, then it can pass in doms_new == NULL,
7185 * and partition_sched_domains() will fallback to the single partition
7188 * Call with hotplug lock held
7190 void partition_sched_domains(int ndoms_new
, cpumask_t
*doms_new
)
7196 /* always unregister in case we don't destroy any domains */
7197 unregister_sched_domain_sysctl();
7199 if (doms_new
== NULL
) {
7201 doms_new
= &fallback_doms
;
7202 cpus_andnot(doms_new
[0], cpu_online_map
, cpu_isolated_map
);
7205 /* Destroy deleted domains */
7206 for (i
= 0; i
< ndoms_cur
; i
++) {
7207 for (j
= 0; j
< ndoms_new
; j
++) {
7208 if (cpus_equal(doms_cur
[i
], doms_new
[j
]))
7211 /* no match - a current sched domain not in new doms_new[] */
7212 detach_destroy_domains(doms_cur
+ i
);
7217 /* Build new domains */
7218 for (i
= 0; i
< ndoms_new
; i
++) {
7219 for (j
= 0; j
< ndoms_cur
; j
++) {
7220 if (cpus_equal(doms_new
[i
], doms_cur
[j
]))
7223 /* no match - add a new doms_new */
7224 build_sched_domains(doms_new
+ i
);
7229 /* Remember the new sched domains */
7230 if (doms_cur
!= &fallback_doms
)
7232 doms_cur
= doms_new
;
7233 ndoms_cur
= ndoms_new
;
7235 register_sched_domain_sysctl();
7240 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7241 int arch_reinit_sched_domains(void)
7246 detach_destroy_domains(&cpu_online_map
);
7247 err
= arch_init_sched_domains(&cpu_online_map
);
7253 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7257 if (buf
[0] != '0' && buf
[0] != '1')
7261 sched_smt_power_savings
= (buf
[0] == '1');
7263 sched_mc_power_savings
= (buf
[0] == '1');
7265 ret
= arch_reinit_sched_domains();
7267 return ret
? ret
: count
;
7270 #ifdef CONFIG_SCHED_MC
7271 static ssize_t
sched_mc_power_savings_show(struct sys_device
*dev
, char *page
)
7273 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7275 static ssize_t
sched_mc_power_savings_store(struct sys_device
*dev
,
7276 const char *buf
, size_t count
)
7278 return sched_power_savings_store(buf
, count
, 0);
7280 static SYSDEV_ATTR(sched_mc_power_savings
, 0644, sched_mc_power_savings_show
,
7281 sched_mc_power_savings_store
);
7284 #ifdef CONFIG_SCHED_SMT
7285 static ssize_t
sched_smt_power_savings_show(struct sys_device
*dev
, char *page
)
7287 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7289 static ssize_t
sched_smt_power_savings_store(struct sys_device
*dev
,
7290 const char *buf
, size_t count
)
7292 return sched_power_savings_store(buf
, count
, 1);
7294 static SYSDEV_ATTR(sched_smt_power_savings
, 0644, sched_smt_power_savings_show
,
7295 sched_smt_power_savings_store
);
7298 int sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7302 #ifdef CONFIG_SCHED_SMT
7304 err
= sysfs_create_file(&cls
->kset
.kobj
,
7305 &attr_sched_smt_power_savings
.attr
);
7307 #ifdef CONFIG_SCHED_MC
7308 if (!err
&& mc_capable())
7309 err
= sysfs_create_file(&cls
->kset
.kobj
,
7310 &attr_sched_mc_power_savings
.attr
);
7317 * Force a reinitialization of the sched domains hierarchy. The domains
7318 * and groups cannot be updated in place without racing with the balancing
7319 * code, so we temporarily attach all running cpus to the NULL domain
7320 * which will prevent rebalancing while the sched domains are recalculated.
7322 static int update_sched_domains(struct notifier_block
*nfb
,
7323 unsigned long action
, void *hcpu
)
7326 case CPU_UP_PREPARE
:
7327 case CPU_UP_PREPARE_FROZEN
:
7328 case CPU_DOWN_PREPARE
:
7329 case CPU_DOWN_PREPARE_FROZEN
:
7330 detach_destroy_domains(&cpu_online_map
);
7333 case CPU_UP_CANCELED
:
7334 case CPU_UP_CANCELED_FROZEN
:
7335 case CPU_DOWN_FAILED
:
7336 case CPU_DOWN_FAILED_FROZEN
:
7338 case CPU_ONLINE_FROZEN
:
7340 case CPU_DEAD_FROZEN
:
7342 * Fall through and re-initialise the domains.
7349 /* The hotplug lock is already held by cpu_up/cpu_down */
7350 arch_init_sched_domains(&cpu_online_map
);
7355 void __init
sched_init_smp(void)
7357 cpumask_t non_isolated_cpus
;
7359 #if defined(CONFIG_NUMA)
7360 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7362 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7365 arch_init_sched_domains(&cpu_online_map
);
7366 cpus_andnot(non_isolated_cpus
, cpu_possible_map
, cpu_isolated_map
);
7367 if (cpus_empty(non_isolated_cpus
))
7368 cpu_set(smp_processor_id(), non_isolated_cpus
);
7370 /* XXX: Theoretical race here - CPU may be hotplugged now */
7371 hotcpu_notifier(update_sched_domains
, 0);
7373 /* Move init over to a non-isolated CPU */
7374 if (set_cpus_allowed_ptr(current
, &non_isolated_cpus
) < 0)
7376 sched_init_granularity();
7379 void __init
sched_init_smp(void)
7381 #if defined(CONFIG_NUMA)
7382 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7384 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7386 sched_init_granularity();
7388 #endif /* CONFIG_SMP */
7390 int in_sched_functions(unsigned long addr
)
7392 return in_lock_functions(addr
) ||
7393 (addr
>= (unsigned long)__sched_text_start
7394 && addr
< (unsigned long)__sched_text_end
);
7397 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7399 cfs_rq
->tasks_timeline
= RB_ROOT
;
7400 #ifdef CONFIG_FAIR_GROUP_SCHED
7403 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7406 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7408 struct rt_prio_array
*array
;
7411 array
= &rt_rq
->active
;
7412 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7413 INIT_LIST_HEAD(array
->queue
+ i
);
7414 __clear_bit(i
, array
->bitmap
);
7416 /* delimiter for bitsearch: */
7417 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7419 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7420 rt_rq
->highest_prio
= MAX_RT_PRIO
;
7423 rt_rq
->rt_nr_migratory
= 0;
7424 rt_rq
->overloaded
= 0;
7428 rt_rq
->rt_throttled
= 0;
7429 rt_rq
->rt_runtime
= 0;
7430 spin_lock_init(&rt_rq
->rt_runtime_lock
);
7432 #ifdef CONFIG_RT_GROUP_SCHED
7433 rt_rq
->rt_nr_boosted
= 0;
7438 #ifdef CONFIG_FAIR_GROUP_SCHED
7439 static void init_tg_cfs_entry(struct rq
*rq
, struct task_group
*tg
,
7440 struct cfs_rq
*cfs_rq
, struct sched_entity
*se
,
7443 tg
->cfs_rq
[cpu
] = cfs_rq
;
7444 init_cfs_rq(cfs_rq
, rq
);
7447 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7450 se
->cfs_rq
= &rq
->cfs
;
7452 se
->load
.weight
= tg
->shares
;
7453 se
->load
.inv_weight
= div64_64(1ULL<<32, se
->load
.weight
);
7458 #ifdef CONFIG_RT_GROUP_SCHED
7459 static void init_tg_rt_entry(struct rq
*rq
, struct task_group
*tg
,
7460 struct rt_rq
*rt_rq
, struct sched_rt_entity
*rt_se
,
7463 tg
->rt_rq
[cpu
] = rt_rq
;
7464 init_rt_rq(rt_rq
, rq
);
7466 rt_rq
->rt_se
= rt_se
;
7467 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7469 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7471 tg
->rt_se
[cpu
] = rt_se
;
7472 rt_se
->rt_rq
= &rq
->rt
;
7473 rt_se
->my_q
= rt_rq
;
7474 rt_se
->parent
= NULL
;
7475 INIT_LIST_HEAD(&rt_se
->run_list
);
7479 void __init
sched_init(void)
7481 int highest_cpu
= 0;
7483 unsigned long alloc_size
= 0, ptr
;
7485 #ifdef CONFIG_FAIR_GROUP_SCHED
7486 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7488 #ifdef CONFIG_RT_GROUP_SCHED
7489 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7492 * As sched_init() is called before page_alloc is setup,
7493 * we use alloc_bootmem().
7496 ptr
= (unsigned long)alloc_bootmem_low(alloc_size
);
7498 #ifdef CONFIG_FAIR_GROUP_SCHED
7499 init_task_group
.se
= (struct sched_entity
**)ptr
;
7500 ptr
+= nr_cpu_ids
* sizeof(void **);
7502 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7503 ptr
+= nr_cpu_ids
* sizeof(void **);
7505 #ifdef CONFIG_RT_GROUP_SCHED
7506 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7507 ptr
+= nr_cpu_ids
* sizeof(void **);
7509 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7514 init_defrootdomain();
7517 init_rt_bandwidth(&def_rt_bandwidth
,
7518 global_rt_period(), global_rt_runtime());
7520 #ifdef CONFIG_RT_GROUP_SCHED
7521 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7522 global_rt_period(), global_rt_runtime());
7525 #ifdef CONFIG_GROUP_SCHED
7526 list_add(&init_task_group
.list
, &task_groups
);
7529 for_each_possible_cpu(i
) {
7533 spin_lock_init(&rq
->lock
);
7534 lockdep_set_class(&rq
->lock
, &rq
->rq_lock_key
);
7537 update_last_tick_seen(rq
);
7538 init_cfs_rq(&rq
->cfs
, rq
);
7539 init_rt_rq(&rq
->rt
, rq
);
7540 #ifdef CONFIG_FAIR_GROUP_SCHED
7541 init_task_group
.shares
= init_task_group_load
;
7542 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7543 init_tg_cfs_entry(rq
, &init_task_group
,
7544 &per_cpu(init_cfs_rq
, i
),
7545 &per_cpu(init_sched_entity
, i
), i
, 1);
7548 #ifdef CONFIG_RT_GROUP_SCHED
7549 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7550 init_tg_rt_entry(rq
, &init_task_group
,
7551 &per_cpu(init_rt_rq
, i
),
7552 &per_cpu(init_sched_rt_entity
, i
), i
, 1);
7554 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7557 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7558 rq
->cpu_load
[j
] = 0;
7562 rq
->active_balance
= 0;
7563 rq
->next_balance
= jiffies
;
7566 rq
->migration_thread
= NULL
;
7567 INIT_LIST_HEAD(&rq
->migration_queue
);
7568 rq_attach_root(rq
, &def_root_domain
);
7571 atomic_set(&rq
->nr_iowait
, 0);
7575 set_load_weight(&init_task
);
7577 #ifdef CONFIG_PREEMPT_NOTIFIERS
7578 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7582 nr_cpu_ids
= highest_cpu
+ 1;
7583 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
, NULL
);
7586 #ifdef CONFIG_RT_MUTEXES
7587 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7591 * The boot idle thread does lazy MMU switching as well:
7593 atomic_inc(&init_mm
.mm_count
);
7594 enter_lazy_tlb(&init_mm
, current
);
7597 * Make us the idle thread. Technically, schedule() should not be
7598 * called from this thread, however somewhere below it might be,
7599 * but because we are the idle thread, we just pick up running again
7600 * when this runqueue becomes "idle".
7602 init_idle(current
, smp_processor_id());
7604 * During early bootup we pretend to be a normal task:
7606 current
->sched_class
= &fair_sched_class
;
7608 scheduler_running
= 1;
7611 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7612 void __might_sleep(char *file
, int line
)
7615 static unsigned long prev_jiffy
; /* ratelimiting */
7617 if ((in_atomic() || irqs_disabled()) &&
7618 system_state
== SYSTEM_RUNNING
&& !oops_in_progress
) {
7619 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7621 prev_jiffy
= jiffies
;
7622 printk(KERN_ERR
"BUG: sleeping function called from invalid"
7623 " context at %s:%d\n", file
, line
);
7624 printk("in_atomic():%d, irqs_disabled():%d\n",
7625 in_atomic(), irqs_disabled());
7626 debug_show_held_locks(current
);
7627 if (irqs_disabled())
7628 print_irqtrace_events(current
);
7633 EXPORT_SYMBOL(__might_sleep
);
7636 #ifdef CONFIG_MAGIC_SYSRQ
7637 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7640 update_rq_clock(rq
);
7641 on_rq
= p
->se
.on_rq
;
7643 deactivate_task(rq
, p
, 0);
7644 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7646 activate_task(rq
, p
, 0);
7647 resched_task(rq
->curr
);
7651 void normalize_rt_tasks(void)
7653 struct task_struct
*g
, *p
;
7654 unsigned long flags
;
7657 read_lock_irqsave(&tasklist_lock
, flags
);
7658 do_each_thread(g
, p
) {
7660 * Only normalize user tasks:
7665 p
->se
.exec_start
= 0;
7666 #ifdef CONFIG_SCHEDSTATS
7667 p
->se
.wait_start
= 0;
7668 p
->se
.sleep_start
= 0;
7669 p
->se
.block_start
= 0;
7671 task_rq(p
)->clock
= 0;
7675 * Renice negative nice level userspace
7678 if (TASK_NICE(p
) < 0 && p
->mm
)
7679 set_user_nice(p
, 0);
7683 spin_lock(&p
->pi_lock
);
7684 rq
= __task_rq_lock(p
);
7686 normalize_task(rq
, p
);
7688 __task_rq_unlock(rq
);
7689 spin_unlock(&p
->pi_lock
);
7690 } while_each_thread(g
, p
);
7692 read_unlock_irqrestore(&tasklist_lock
, flags
);
7695 #endif /* CONFIG_MAGIC_SYSRQ */
7699 * These functions are only useful for the IA64 MCA handling.
7701 * They can only be called when the whole system has been
7702 * stopped - every CPU needs to be quiescent, and no scheduling
7703 * activity can take place. Using them for anything else would
7704 * be a serious bug, and as a result, they aren't even visible
7705 * under any other configuration.
7709 * curr_task - return the current task for a given cpu.
7710 * @cpu: the processor in question.
7712 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7714 struct task_struct
*curr_task(int cpu
)
7716 return cpu_curr(cpu
);
7720 * set_curr_task - set the current task for a given cpu.
7721 * @cpu: the processor in question.
7722 * @p: the task pointer to set.
7724 * Description: This function must only be used when non-maskable interrupts
7725 * are serviced on a separate stack. It allows the architecture to switch the
7726 * notion of the current task on a cpu in a non-blocking manner. This function
7727 * must be called with all CPU's synchronized, and interrupts disabled, the
7728 * and caller must save the original value of the current task (see
7729 * curr_task() above) and restore that value before reenabling interrupts and
7730 * re-starting the system.
7732 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7734 void set_curr_task(int cpu
, struct task_struct
*p
)
7741 #ifdef CONFIG_FAIR_GROUP_SCHED
7742 static void free_fair_sched_group(struct task_group
*tg
)
7746 for_each_possible_cpu(i
) {
7748 kfree(tg
->cfs_rq
[i
]);
7757 static int alloc_fair_sched_group(struct task_group
*tg
)
7759 struct cfs_rq
*cfs_rq
;
7760 struct sched_entity
*se
;
7764 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
7767 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
7771 tg
->shares
= NICE_0_LOAD
;
7773 for_each_possible_cpu(i
) {
7776 cfs_rq
= kmalloc_node(sizeof(struct cfs_rq
),
7777 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7781 se
= kmalloc_node(sizeof(struct sched_entity
),
7782 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7786 init_tg_cfs_entry(rq
, tg
, cfs_rq
, se
, i
, 0);
7795 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7797 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
7798 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
7801 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
7803 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
7806 static inline void free_fair_sched_group(struct task_group
*tg
)
7810 static inline int alloc_fair_sched_group(struct task_group
*tg
)
7815 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7819 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
7824 #ifdef CONFIG_RT_GROUP_SCHED
7825 static void free_rt_sched_group(struct task_group
*tg
)
7829 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
7831 for_each_possible_cpu(i
) {
7833 kfree(tg
->rt_rq
[i
]);
7835 kfree(tg
->rt_se
[i
]);
7842 static int alloc_rt_sched_group(struct task_group
*tg
)
7844 struct rt_rq
*rt_rq
;
7845 struct sched_rt_entity
*rt_se
;
7849 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
7852 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
7856 init_rt_bandwidth(&tg
->rt_bandwidth
,
7857 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
7859 for_each_possible_cpu(i
) {
7862 rt_rq
= kmalloc_node(sizeof(struct rt_rq
),
7863 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7867 rt_se
= kmalloc_node(sizeof(struct sched_rt_entity
),
7868 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
7872 init_tg_rt_entry(rq
, tg
, rt_rq
, rt_se
, i
, 0);
7881 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
7883 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
7884 &cpu_rq(cpu
)->leaf_rt_rq_list
);
7887 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
7889 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
7892 static inline void free_rt_sched_group(struct task_group
*tg
)
7896 static inline int alloc_rt_sched_group(struct task_group
*tg
)
7901 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
7905 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
7910 #ifdef CONFIG_GROUP_SCHED
7911 static void free_sched_group(struct task_group
*tg
)
7913 free_fair_sched_group(tg
);
7914 free_rt_sched_group(tg
);
7918 /* allocate runqueue etc for a new task group */
7919 struct task_group
*sched_create_group(void)
7921 struct task_group
*tg
;
7922 unsigned long flags
;
7925 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
7927 return ERR_PTR(-ENOMEM
);
7929 if (!alloc_fair_sched_group(tg
))
7932 if (!alloc_rt_sched_group(tg
))
7935 spin_lock_irqsave(&task_group_lock
, flags
);
7936 for_each_possible_cpu(i
) {
7937 register_fair_sched_group(tg
, i
);
7938 register_rt_sched_group(tg
, i
);
7940 list_add_rcu(&tg
->list
, &task_groups
);
7941 spin_unlock_irqrestore(&task_group_lock
, flags
);
7946 free_sched_group(tg
);
7947 return ERR_PTR(-ENOMEM
);
7950 /* rcu callback to free various structures associated with a task group */
7951 static void free_sched_group_rcu(struct rcu_head
*rhp
)
7953 /* now it should be safe to free those cfs_rqs */
7954 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
7957 /* Destroy runqueue etc associated with a task group */
7958 void sched_destroy_group(struct task_group
*tg
)
7960 unsigned long flags
;
7963 spin_lock_irqsave(&task_group_lock
, flags
);
7964 for_each_possible_cpu(i
) {
7965 unregister_fair_sched_group(tg
, i
);
7966 unregister_rt_sched_group(tg
, i
);
7968 list_del_rcu(&tg
->list
);
7969 spin_unlock_irqrestore(&task_group_lock
, flags
);
7971 /* wait for possible concurrent references to cfs_rqs complete */
7972 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
7975 /* change task's runqueue when it moves between groups.
7976 * The caller of this function should have put the task in its new group
7977 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
7978 * reflect its new group.
7980 void sched_move_task(struct task_struct
*tsk
)
7983 unsigned long flags
;
7986 rq
= task_rq_lock(tsk
, &flags
);
7988 update_rq_clock(rq
);
7990 running
= task_current(rq
, tsk
);
7991 on_rq
= tsk
->se
.on_rq
;
7994 dequeue_task(rq
, tsk
, 0);
7995 if (unlikely(running
))
7996 tsk
->sched_class
->put_prev_task(rq
, tsk
);
7998 set_task_rq(tsk
, task_cpu(tsk
));
8000 #ifdef CONFIG_FAIR_GROUP_SCHED
8001 if (tsk
->sched_class
->moved_group
)
8002 tsk
->sched_class
->moved_group(tsk
);
8005 if (unlikely(running
))
8006 tsk
->sched_class
->set_curr_task(rq
);
8008 enqueue_task(rq
, tsk
, 0);
8010 task_rq_unlock(rq
, &flags
);
8014 #ifdef CONFIG_FAIR_GROUP_SCHED
8015 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8017 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8018 struct rq
*rq
= cfs_rq
->rq
;
8021 spin_lock_irq(&rq
->lock
);
8025 dequeue_entity(cfs_rq
, se
, 0);
8027 se
->load
.weight
= shares
;
8028 se
->load
.inv_weight
= div64_64((1ULL<<32), shares
);
8031 enqueue_entity(cfs_rq
, se
, 0);
8033 spin_unlock_irq(&rq
->lock
);
8036 static DEFINE_MUTEX(shares_mutex
);
8038 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8041 unsigned long flags
;
8044 * A weight of 0 or 1 can cause arithmetics problems.
8045 * (The default weight is 1024 - so there's no practical
8046 * limitation from this.)
8051 mutex_lock(&shares_mutex
);
8052 if (tg
->shares
== shares
)
8055 spin_lock_irqsave(&task_group_lock
, flags
);
8056 for_each_possible_cpu(i
)
8057 unregister_fair_sched_group(tg
, i
);
8058 spin_unlock_irqrestore(&task_group_lock
, flags
);
8060 /* wait for any ongoing reference to this group to finish */
8061 synchronize_sched();
8064 * Now we are free to modify the group's share on each cpu
8065 * w/o tripping rebalance_share or load_balance_fair.
8067 tg
->shares
= shares
;
8068 for_each_possible_cpu(i
)
8069 set_se_shares(tg
->se
[i
], shares
);
8072 * Enable load balance activity on this group, by inserting it back on
8073 * each cpu's rq->leaf_cfs_rq_list.
8075 spin_lock_irqsave(&task_group_lock
, flags
);
8076 for_each_possible_cpu(i
)
8077 register_fair_sched_group(tg
, i
);
8078 spin_unlock_irqrestore(&task_group_lock
, flags
);
8080 mutex_unlock(&shares_mutex
);
8084 unsigned long sched_group_shares(struct task_group
*tg
)
8090 #ifdef CONFIG_RT_GROUP_SCHED
8092 * Ensure that the real time constraints are schedulable.
8094 static DEFINE_MUTEX(rt_constraints_mutex
);
8096 static unsigned long to_ratio(u64 period
, u64 runtime
)
8098 if (runtime
== RUNTIME_INF
)
8101 return div64_64(runtime
<< 16, period
);
8104 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8106 struct task_group
*tgi
;
8107 unsigned long total
= 0;
8108 unsigned long global_ratio
=
8109 to_ratio(global_rt_period(), global_rt_runtime());
8112 list_for_each_entry_rcu(tgi
, &task_groups
, list
) {
8116 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8117 tgi
->rt_bandwidth
.rt_runtime
);
8121 return total
+ to_ratio(period
, runtime
) < global_ratio
;
8124 /* Must be called with tasklist_lock held */
8125 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8127 struct task_struct
*g
, *p
;
8128 do_each_thread(g
, p
) {
8129 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8131 } while_each_thread(g
, p
);
8135 static int tg_set_bandwidth(struct task_group
*tg
,
8136 u64 rt_period
, u64 rt_runtime
)
8140 mutex_lock(&rt_constraints_mutex
);
8141 read_lock(&tasklist_lock
);
8142 if (rt_runtime
== 0 && tg_has_rt_tasks(tg
)) {
8146 if (!__rt_schedulable(tg
, rt_period
, rt_runtime
)) {
8151 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8152 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8153 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8155 for_each_possible_cpu(i
) {
8156 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8158 spin_lock(&rt_rq
->rt_runtime_lock
);
8159 rt_rq
->rt_runtime
= rt_runtime
;
8160 spin_unlock(&rt_rq
->rt_runtime_lock
);
8162 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8164 read_unlock(&tasklist_lock
);
8165 mutex_unlock(&rt_constraints_mutex
);
8170 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8172 u64 rt_runtime
, rt_period
;
8174 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8175 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8176 if (rt_runtime_us
< 0)
8177 rt_runtime
= RUNTIME_INF
;
8179 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8182 long sched_group_rt_runtime(struct task_group
*tg
)
8186 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8189 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8190 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8191 return rt_runtime_us
;
8194 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8196 u64 rt_runtime
, rt_period
;
8198 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8199 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8201 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8204 long sched_group_rt_period(struct task_group
*tg
)
8208 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8209 do_div(rt_period_us
, NSEC_PER_USEC
);
8210 return rt_period_us
;
8213 static int sched_rt_global_constraints(void)
8217 mutex_lock(&rt_constraints_mutex
);
8218 if (!__rt_schedulable(NULL
, 1, 0))
8220 mutex_unlock(&rt_constraints_mutex
);
8225 static int sched_rt_global_constraints(void)
8227 unsigned long flags
;
8230 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8231 for_each_possible_cpu(i
) {
8232 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8234 spin_lock(&rt_rq
->rt_runtime_lock
);
8235 rt_rq
->rt_runtime
= global_rt_runtime();
8236 spin_unlock(&rt_rq
->rt_runtime_lock
);
8238 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8244 int sched_rt_handler(struct ctl_table
*table
, int write
,
8245 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
8249 int old_period
, old_runtime
;
8250 static DEFINE_MUTEX(mutex
);
8253 old_period
= sysctl_sched_rt_period
;
8254 old_runtime
= sysctl_sched_rt_runtime
;
8256 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
8258 if (!ret
&& write
) {
8259 ret
= sched_rt_global_constraints();
8261 sysctl_sched_rt_period
= old_period
;
8262 sysctl_sched_rt_runtime
= old_runtime
;
8264 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8265 def_rt_bandwidth
.rt_period
=
8266 ns_to_ktime(global_rt_period());
8269 mutex_unlock(&mutex
);
8274 #ifdef CONFIG_CGROUP_SCHED
8276 /* return corresponding task_group object of a cgroup */
8277 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8279 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8280 struct task_group
, css
);
8283 static struct cgroup_subsys_state
*
8284 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8286 struct task_group
*tg
;
8288 if (!cgrp
->parent
) {
8289 /* This is early initialization for the top cgroup */
8290 init_task_group
.css
.cgroup
= cgrp
;
8291 return &init_task_group
.css
;
8294 /* we support only 1-level deep hierarchical scheduler atm */
8295 if (cgrp
->parent
->parent
)
8296 return ERR_PTR(-EINVAL
);
8298 tg
= sched_create_group();
8300 return ERR_PTR(-ENOMEM
);
8302 /* Bind the cgroup to task_group object we just created */
8303 tg
->css
.cgroup
= cgrp
;
8309 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8311 struct task_group
*tg
= cgroup_tg(cgrp
);
8313 sched_destroy_group(tg
);
8317 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8318 struct task_struct
*tsk
)
8320 #ifdef CONFIG_RT_GROUP_SCHED
8321 /* Don't accept realtime tasks when there is no way for them to run */
8322 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
8325 /* We don't support RT-tasks being in separate groups */
8326 if (tsk
->sched_class
!= &fair_sched_class
)
8334 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8335 struct cgroup
*old_cont
, struct task_struct
*tsk
)
8337 sched_move_task(tsk
);
8340 #ifdef CONFIG_FAIR_GROUP_SCHED
8341 static int cpu_shares_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8344 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8347 static u64
cpu_shares_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8349 struct task_group
*tg
= cgroup_tg(cgrp
);
8351 return (u64
) tg
->shares
;
8355 #ifdef CONFIG_RT_GROUP_SCHED
8356 static ssize_t
cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8358 const char __user
*userbuf
,
8359 size_t nbytes
, loff_t
*unused_ppos
)
8368 if (nbytes
>= sizeof(buffer
))
8370 if (copy_from_user(buffer
, userbuf
, nbytes
))
8373 buffer
[nbytes
] = 0; /* nul-terminate */
8375 /* strip newline if necessary */
8376 if (nbytes
&& (buffer
[nbytes
-1] == '\n'))
8377 buffer
[nbytes
-1] = 0;
8378 val
= simple_strtoll(buffer
, &end
, 0);
8382 /* Pass to subsystem */
8383 retval
= sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8389 static ssize_t
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
,
8391 char __user
*buf
, size_t nbytes
,
8395 long val
= sched_group_rt_runtime(cgroup_tg(cgrp
));
8396 int len
= sprintf(tmp
, "%ld\n", val
);
8398 return simple_read_from_buffer(buf
, nbytes
, ppos
, tmp
, len
);
8401 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8404 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8407 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8409 return sched_group_rt_period(cgroup_tg(cgrp
));
8413 static struct cftype cpu_files
[] = {
8414 #ifdef CONFIG_FAIR_GROUP_SCHED
8417 .read_uint
= cpu_shares_read_uint
,
8418 .write_uint
= cpu_shares_write_uint
,
8421 #ifdef CONFIG_RT_GROUP_SCHED
8423 .name
= "rt_runtime_us",
8424 .read
= cpu_rt_runtime_read
,
8425 .write
= cpu_rt_runtime_write
,
8428 .name
= "rt_period_us",
8429 .read_uint
= cpu_rt_period_read_uint
,
8430 .write_uint
= cpu_rt_period_write_uint
,
8435 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8437 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8440 struct cgroup_subsys cpu_cgroup_subsys
= {
8442 .create
= cpu_cgroup_create
,
8443 .destroy
= cpu_cgroup_destroy
,
8444 .can_attach
= cpu_cgroup_can_attach
,
8445 .attach
= cpu_cgroup_attach
,
8446 .populate
= cpu_cgroup_populate
,
8447 .subsys_id
= cpu_cgroup_subsys_id
,
8451 #endif /* CONFIG_CGROUP_SCHED */
8453 #ifdef CONFIG_CGROUP_CPUACCT
8456 * CPU accounting code for task groups.
8458 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8459 * (balbir@in.ibm.com).
8462 /* track cpu usage of a group of tasks */
8464 struct cgroup_subsys_state css
;
8465 /* cpuusage holds pointer to a u64-type object on every cpu */
8469 struct cgroup_subsys cpuacct_subsys
;
8471 /* return cpu accounting group corresponding to this container */
8472 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8474 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8475 struct cpuacct
, css
);
8478 /* return cpu accounting group to which this task belongs */
8479 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8481 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8482 struct cpuacct
, css
);
8485 /* create a new cpu accounting group */
8486 static struct cgroup_subsys_state
*cpuacct_create(
8487 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8489 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8492 return ERR_PTR(-ENOMEM
);
8494 ca
->cpuusage
= alloc_percpu(u64
);
8495 if (!ca
->cpuusage
) {
8497 return ERR_PTR(-ENOMEM
);
8503 /* destroy an existing cpu accounting group */
8505 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8507 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8509 free_percpu(ca
->cpuusage
);
8513 /* return total cpu usage (in nanoseconds) of a group */
8514 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8516 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8517 u64 totalcpuusage
= 0;
8520 for_each_possible_cpu(i
) {
8521 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8524 * Take rq->lock to make 64-bit addition safe on 32-bit
8527 spin_lock_irq(&cpu_rq(i
)->lock
);
8528 totalcpuusage
+= *cpuusage
;
8529 spin_unlock_irq(&cpu_rq(i
)->lock
);
8532 return totalcpuusage
;
8535 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8538 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8547 for_each_possible_cpu(i
) {
8548 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8550 spin_lock_irq(&cpu_rq(i
)->lock
);
8552 spin_unlock_irq(&cpu_rq(i
)->lock
);
8558 static struct cftype files
[] = {
8561 .read_uint
= cpuusage_read
,
8562 .write_uint
= cpuusage_write
,
8566 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8568 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8572 * charge this task's execution time to its accounting group.
8574 * called with rq->lock held.
8576 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8580 if (!cpuacct_subsys
.active
)
8585 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, task_cpu(tsk
));
8587 *cpuusage
+= cputime
;
8591 struct cgroup_subsys cpuacct_subsys
= {
8593 .create
= cpuacct_create
,
8594 .destroy
= cpuacct_destroy
,
8595 .populate
= cpuacct_populate
,
8596 .subsys_id
= cpuacct_subsys_id
,
8598 #endif /* CONFIG_CGROUP_CPUACCT */