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/perf_counter.h>
43 #include <linux/security.h>
44 #include <linux/notifier.h>
45 #include <linux/profile.h>
46 #include <linux/freezer.h>
47 #include <linux/vmalloc.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/pid_namespace.h>
51 #include <linux/smp.h>
52 #include <linux/threads.h>
53 #include <linux/timer.h>
54 #include <linux/rcupdate.h>
55 #include <linux/cpu.h>
56 #include <linux/cpuset.h>
57 #include <linux/percpu.h>
58 #include <linux/kthread.h>
59 #include <linux/proc_fs.h>
60 #include <linux/seq_file.h>
61 #include <linux/sysctl.h>
62 #include <linux/syscalls.h>
63 #include <linux/times.h>
64 #include <linux/tsacct_kern.h>
65 #include <linux/kprobes.h>
66 #include <linux/delayacct.h>
67 #include <linux/reciprocal_div.h>
68 #include <linux/unistd.h>
69 #include <linux/pagemap.h>
70 #include <linux/hrtimer.h>
71 #include <linux/tick.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
77 #include <asm/irq_regs.h>
79 #include "sched_cpupri.h"
81 #define CREATE_TRACE_POINTS
82 #include <trace/events/sched.h>
85 * Convert user-nice values [ -20 ... 0 ... 19 ]
86 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
89 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
90 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
91 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
94 * 'User priority' is the nice value converted to something we
95 * can work with better when scaling various scheduler parameters,
96 * it's a [ 0 ... 39 ] range.
98 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
99 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
100 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
103 * Helpers for converting nanosecond timing to jiffy resolution
105 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
107 #define NICE_0_LOAD SCHED_LOAD_SCALE
108 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
111 * These are the 'tuning knobs' of the scheduler:
113 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
114 * Timeslices get refilled after they expire.
116 #define DEF_TIMESLICE (100 * HZ / 1000)
119 * single value that denotes runtime == period, ie unlimited time.
121 #define RUNTIME_INF ((u64)~0ULL)
125 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
128 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
129 * Since cpu_power is a 'constant', we can use a reciprocal divide.
131 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
133 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
137 * Each time a sched group cpu_power is changed,
138 * we must compute its reciprocal value
140 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
142 sg
->__cpu_power
+= val
;
143 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
147 static inline int rt_policy(int policy
)
149 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
154 static inline int task_has_rt_policy(struct task_struct
*p
)
156 return rt_policy(p
->policy
);
160 * This is the priority-queue data structure of the RT scheduling class:
162 struct rt_prio_array
{
163 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
164 struct list_head queue
[MAX_RT_PRIO
];
167 struct rt_bandwidth
{
168 /* nests inside the rq lock: */
169 spinlock_t rt_runtime_lock
;
172 struct hrtimer rt_period_timer
;
175 static struct rt_bandwidth def_rt_bandwidth
;
177 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
179 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
181 struct rt_bandwidth
*rt_b
=
182 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
188 now
= hrtimer_cb_get_time(timer
);
189 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
194 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
197 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
201 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
203 rt_b
->rt_period
= ns_to_ktime(period
);
204 rt_b
->rt_runtime
= runtime
;
206 spin_lock_init(&rt_b
->rt_runtime_lock
);
208 hrtimer_init(&rt_b
->rt_period_timer
,
209 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
210 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
213 static inline int rt_bandwidth_enabled(void)
215 return sysctl_sched_rt_runtime
>= 0;
218 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
222 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
225 if (hrtimer_active(&rt_b
->rt_period_timer
))
228 spin_lock(&rt_b
->rt_runtime_lock
);
233 if (hrtimer_active(&rt_b
->rt_period_timer
))
236 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
237 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
239 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
240 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
241 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
242 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
243 HRTIMER_MODE_ABS_PINNED
, 0);
245 spin_unlock(&rt_b
->rt_runtime_lock
);
248 #ifdef CONFIG_RT_GROUP_SCHED
249 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
251 hrtimer_cancel(&rt_b
->rt_period_timer
);
256 * sched_domains_mutex serializes calls to arch_init_sched_domains,
257 * detach_destroy_domains and partition_sched_domains.
259 static DEFINE_MUTEX(sched_domains_mutex
);
261 #ifdef CONFIG_GROUP_SCHED
263 #include <linux/cgroup.h>
267 static LIST_HEAD(task_groups
);
269 /* task group related information */
271 #ifdef CONFIG_CGROUP_SCHED
272 struct cgroup_subsys_state css
;
275 #ifdef CONFIG_USER_SCHED
279 #ifdef CONFIG_FAIR_GROUP_SCHED
280 /* schedulable entities of this group on each cpu */
281 struct sched_entity
**se
;
282 /* runqueue "owned" by this group on each cpu */
283 struct cfs_rq
**cfs_rq
;
284 unsigned long shares
;
287 #ifdef CONFIG_RT_GROUP_SCHED
288 struct sched_rt_entity
**rt_se
;
289 struct rt_rq
**rt_rq
;
291 struct rt_bandwidth rt_bandwidth
;
295 struct list_head list
;
297 struct task_group
*parent
;
298 struct list_head siblings
;
299 struct list_head children
;
302 #ifdef CONFIG_USER_SCHED
304 /* Helper function to pass uid information to create_sched_user() */
305 void set_tg_uid(struct user_struct
*user
)
307 user
->tg
->uid
= user
->uid
;
312 * Every UID task group (including init_task_group aka UID-0) will
313 * be a child to this group.
315 struct task_group root_task_group
;
317 #ifdef CONFIG_FAIR_GROUP_SCHED
318 /* Default task group's sched entity on each cpu */
319 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
320 /* Default task group's cfs_rq on each cpu */
321 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
322 #endif /* CONFIG_FAIR_GROUP_SCHED */
324 #ifdef CONFIG_RT_GROUP_SCHED
325 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
326 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
327 #endif /* CONFIG_RT_GROUP_SCHED */
328 #else /* !CONFIG_USER_SCHED */
329 #define root_task_group init_task_group
330 #endif /* CONFIG_USER_SCHED */
332 /* task_group_lock serializes add/remove of task groups and also changes to
333 * a task group's cpu shares.
335 static DEFINE_SPINLOCK(task_group_lock
);
338 static int root_task_group_empty(void)
340 return list_empty(&root_task_group
.children
);
344 #ifdef CONFIG_FAIR_GROUP_SCHED
345 #ifdef CONFIG_USER_SCHED
346 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
347 #else /* !CONFIG_USER_SCHED */
348 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
349 #endif /* CONFIG_USER_SCHED */
352 * A weight of 0 or 1 can cause arithmetics problems.
353 * A weight of a cfs_rq is the sum of weights of which entities
354 * are queued on this cfs_rq, so a weight of a entity should not be
355 * too large, so as the shares value of a task group.
356 * (The default weight is 1024 - so there's no practical
357 * limitation from this.)
360 #define MAX_SHARES (1UL << 18)
362 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
365 /* Default task group.
366 * Every task in system belong to this group at bootup.
368 struct task_group init_task_group
;
370 /* return group to which a task belongs */
371 static inline struct task_group
*task_group(struct task_struct
*p
)
373 struct task_group
*tg
;
375 #ifdef CONFIG_USER_SCHED
377 tg
= __task_cred(p
)->user
->tg
;
379 #elif defined(CONFIG_CGROUP_SCHED)
380 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
381 struct task_group
, css
);
383 tg
= &init_task_group
;
388 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
389 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
391 #ifdef CONFIG_FAIR_GROUP_SCHED
392 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
393 p
->se
.parent
= task_group(p
)->se
[cpu
];
396 #ifdef CONFIG_RT_GROUP_SCHED
397 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
398 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
405 static int root_task_group_empty(void)
411 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
412 static inline struct task_group
*task_group(struct task_struct
*p
)
417 #endif /* CONFIG_GROUP_SCHED */
419 /* CFS-related fields in a runqueue */
421 struct load_weight load
;
422 unsigned long nr_running
;
427 struct rb_root tasks_timeline
;
428 struct rb_node
*rb_leftmost
;
430 struct list_head tasks
;
431 struct list_head
*balance_iterator
;
434 * 'curr' points to currently running entity on this cfs_rq.
435 * It is set to NULL otherwise (i.e when none are currently running).
437 struct sched_entity
*curr
, *next
, *last
;
439 unsigned int nr_spread_over
;
441 #ifdef CONFIG_FAIR_GROUP_SCHED
442 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
445 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
446 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
447 * (like users, containers etc.)
449 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
450 * list is used during load balance.
452 struct list_head leaf_cfs_rq_list
;
453 struct task_group
*tg
; /* group that "owns" this runqueue */
457 * the part of load.weight contributed by tasks
459 unsigned long task_weight
;
462 * h_load = weight * f(tg)
464 * Where f(tg) is the recursive weight fraction assigned to
467 unsigned long h_load
;
470 * this cpu's part of tg->shares
472 unsigned long shares
;
475 * load.weight at the time we set shares
477 unsigned long rq_weight
;
482 /* Real-Time classes' related field in a runqueue: */
484 struct rt_prio_array active
;
485 unsigned long rt_nr_running
;
486 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
488 int curr
; /* highest queued rt task prio */
490 int next
; /* next highest */
495 unsigned long rt_nr_migratory
;
496 unsigned long rt_nr_total
;
498 struct plist_head pushable_tasks
;
503 /* Nests inside the rq lock: */
504 spinlock_t rt_runtime_lock
;
506 #ifdef CONFIG_RT_GROUP_SCHED
507 unsigned long rt_nr_boosted
;
510 struct list_head leaf_rt_rq_list
;
511 struct task_group
*tg
;
512 struct sched_rt_entity
*rt_se
;
519 * We add the notion of a root-domain which will be used to define per-domain
520 * variables. Each exclusive cpuset essentially defines an island domain by
521 * fully partitioning the member cpus from any other cpuset. Whenever a new
522 * exclusive cpuset is created, we also create and attach a new root-domain
529 cpumask_var_t online
;
532 * The "RT overload" flag: it gets set if a CPU has more than
533 * one runnable RT task.
535 cpumask_var_t rto_mask
;
538 struct cpupri cpupri
;
540 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
542 * Preferred wake up cpu nominated by sched_mc balance that will be
543 * used when most cpus are idle in the system indicating overall very
544 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
546 unsigned int sched_mc_preferred_wakeup_cpu
;
551 * By default the system creates a single root-domain with all cpus as
552 * members (mimicking the global state we have today).
554 static struct root_domain def_root_domain
;
559 * This is the main, per-CPU runqueue data structure.
561 * Locking rule: those places that want to lock multiple runqueues
562 * (such as the load balancing or the thread migration code), lock
563 * acquire operations must be ordered by ascending &runqueue.
570 * nr_running and cpu_load should be in the same cacheline because
571 * remote CPUs use both these fields when doing load calculation.
573 unsigned long nr_running
;
574 #define CPU_LOAD_IDX_MAX 5
575 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
577 unsigned long last_tick_seen
;
578 unsigned char in_nohz_recently
;
580 /* capture load from *all* tasks on this cpu: */
581 struct load_weight load
;
582 unsigned long nr_load_updates
;
584 u64 nr_migrations_in
;
589 #ifdef CONFIG_FAIR_GROUP_SCHED
590 /* list of leaf cfs_rq on this cpu: */
591 struct list_head leaf_cfs_rq_list
;
593 #ifdef CONFIG_RT_GROUP_SCHED
594 struct list_head leaf_rt_rq_list
;
598 * This is part of a global counter where only the total sum
599 * over all CPUs matters. A task can increase this counter on
600 * one CPU and if it got migrated afterwards it may decrease
601 * it on another CPU. Always updated under the runqueue lock:
603 unsigned long nr_uninterruptible
;
605 struct task_struct
*curr
, *idle
;
606 unsigned long next_balance
;
607 struct mm_struct
*prev_mm
;
614 struct root_domain
*rd
;
615 struct sched_domain
*sd
;
617 unsigned char idle_at_tick
;
618 /* For active balancing */
622 /* cpu of this runqueue: */
626 unsigned long avg_load_per_task
;
628 struct task_struct
*migration_thread
;
629 struct list_head migration_queue
;
632 /* calc_load related fields */
633 unsigned long calc_load_update
;
634 long calc_load_active
;
636 #ifdef CONFIG_SCHED_HRTICK
638 int hrtick_csd_pending
;
639 struct call_single_data hrtick_csd
;
641 struct hrtimer hrtick_timer
;
644 #ifdef CONFIG_SCHEDSTATS
646 struct sched_info rq_sched_info
;
647 unsigned long long rq_cpu_time
;
648 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
650 /* sys_sched_yield() stats */
651 unsigned int yld_count
;
653 /* schedule() stats */
654 unsigned int sched_switch
;
655 unsigned int sched_count
;
656 unsigned int sched_goidle
;
658 /* try_to_wake_up() stats */
659 unsigned int ttwu_count
;
660 unsigned int ttwu_local
;
663 unsigned int bkl_count
;
667 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
669 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int sync
)
671 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, sync
);
674 static inline int cpu_of(struct rq
*rq
)
684 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
685 * See detach_destroy_domains: synchronize_sched for details.
687 * The domain tree of any CPU may only be accessed from within
688 * preempt-disabled sections.
690 #define for_each_domain(cpu, __sd) \
691 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
693 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
694 #define this_rq() (&__get_cpu_var(runqueues))
695 #define task_rq(p) cpu_rq(task_cpu(p))
696 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
697 #define raw_rq() (&__raw_get_cpu_var(runqueues))
699 inline void update_rq_clock(struct rq
*rq
)
701 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
705 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
707 #ifdef CONFIG_SCHED_DEBUG
708 # define const_debug __read_mostly
710 # define const_debug static const
716 * Returns true if the current cpu runqueue is locked.
717 * This interface allows printk to be called with the runqueue lock
718 * held and know whether or not it is OK to wake up the klogd.
720 int runqueue_is_locked(void)
723 struct rq
*rq
= cpu_rq(cpu
);
726 ret
= spin_is_locked(&rq
->lock
);
732 * Debugging: various feature bits
735 #define SCHED_FEAT(name, enabled) \
736 __SCHED_FEAT_##name ,
739 #include "sched_features.h"
744 #define SCHED_FEAT(name, enabled) \
745 (1UL << __SCHED_FEAT_##name) * enabled |
747 const_debug
unsigned int sysctl_sched_features
=
748 #include "sched_features.h"
753 #ifdef CONFIG_SCHED_DEBUG
754 #define SCHED_FEAT(name, enabled) \
757 static __read_mostly
char *sched_feat_names
[] = {
758 #include "sched_features.h"
764 static int sched_feat_show(struct seq_file
*m
, void *v
)
768 for (i
= 0; sched_feat_names
[i
]; i
++) {
769 if (!(sysctl_sched_features
& (1UL << i
)))
771 seq_printf(m
, "%s ", sched_feat_names
[i
]);
779 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
780 size_t cnt
, loff_t
*ppos
)
790 if (copy_from_user(&buf
, ubuf
, cnt
))
795 if (strncmp(buf
, "NO_", 3) == 0) {
800 for (i
= 0; sched_feat_names
[i
]; i
++) {
801 int len
= strlen(sched_feat_names
[i
]);
803 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
805 sysctl_sched_features
&= ~(1UL << i
);
807 sysctl_sched_features
|= (1UL << i
);
812 if (!sched_feat_names
[i
])
820 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
822 return single_open(filp
, sched_feat_show
, NULL
);
825 static struct file_operations sched_feat_fops
= {
826 .open
= sched_feat_open
,
827 .write
= sched_feat_write
,
830 .release
= single_release
,
833 static __init
int sched_init_debug(void)
835 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
840 late_initcall(sched_init_debug
);
844 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
847 * Number of tasks to iterate in a single balance run.
848 * Limited because this is done with IRQs disabled.
850 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
853 * ratelimit for updating the group shares.
856 unsigned int sysctl_sched_shares_ratelimit
= 250000;
859 * Inject some fuzzyness into changing the per-cpu group shares
860 * this avoids remote rq-locks at the expense of fairness.
863 unsigned int sysctl_sched_shares_thresh
= 4;
866 * period over which we measure -rt task cpu usage in us.
869 unsigned int sysctl_sched_rt_period
= 1000000;
871 static __read_mostly
int scheduler_running
;
874 * part of the period that we allow rt tasks to run in us.
877 int sysctl_sched_rt_runtime
= 950000;
879 static inline u64
global_rt_period(void)
881 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
884 static inline u64
global_rt_runtime(void)
886 if (sysctl_sched_rt_runtime
< 0)
889 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
892 #ifndef prepare_arch_switch
893 # define prepare_arch_switch(next) do { } while (0)
895 #ifndef finish_arch_switch
896 # define finish_arch_switch(prev) do { } while (0)
899 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
901 return rq
->curr
== p
;
904 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
905 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
907 return task_current(rq
, p
);
910 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
914 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
916 #ifdef CONFIG_DEBUG_SPINLOCK
917 /* this is a valid case when another task releases the spinlock */
918 rq
->lock
.owner
= current
;
921 * If we are tracking spinlock dependencies then we have to
922 * fix up the runqueue lock - which gets 'carried over' from
925 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
927 spin_unlock_irq(&rq
->lock
);
930 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
931 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
936 return task_current(rq
, p
);
940 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
944 * We can optimise this out completely for !SMP, because the
945 * SMP rebalancing from interrupt is the only thing that cares
950 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
951 spin_unlock_irq(&rq
->lock
);
953 spin_unlock(&rq
->lock
);
957 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
961 * After ->oncpu is cleared, the task can be moved to a different CPU.
962 * We must ensure this doesn't happen until the switch is completely
968 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
972 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
975 * __task_rq_lock - lock the runqueue a given task resides on.
976 * Must be called interrupts disabled.
978 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
982 struct rq
*rq
= task_rq(p
);
983 spin_lock(&rq
->lock
);
984 if (likely(rq
== task_rq(p
)))
986 spin_unlock(&rq
->lock
);
991 * task_rq_lock - lock the runqueue a given task resides on and disable
992 * interrupts. Note the ordering: we can safely lookup the task_rq without
993 * explicitly disabling preemption.
995 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
1001 local_irq_save(*flags
);
1003 spin_lock(&rq
->lock
);
1004 if (likely(rq
== task_rq(p
)))
1006 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1010 void task_rq_unlock_wait(struct task_struct
*p
)
1012 struct rq
*rq
= task_rq(p
);
1014 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1015 spin_unlock_wait(&rq
->lock
);
1018 static void __task_rq_unlock(struct rq
*rq
)
1019 __releases(rq
->lock
)
1021 spin_unlock(&rq
->lock
);
1024 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
1025 __releases(rq
->lock
)
1027 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1031 * this_rq_lock - lock this runqueue and disable interrupts.
1033 static struct rq
*this_rq_lock(void)
1034 __acquires(rq
->lock
)
1038 local_irq_disable();
1040 spin_lock(&rq
->lock
);
1045 #ifdef CONFIG_SCHED_HRTICK
1047 * Use HR-timers to deliver accurate preemption points.
1049 * Its all a bit involved since we cannot program an hrt while holding the
1050 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1053 * When we get rescheduled we reprogram the hrtick_timer outside of the
1059 * - enabled by features
1060 * - hrtimer is actually high res
1062 static inline int hrtick_enabled(struct rq
*rq
)
1064 if (!sched_feat(HRTICK
))
1066 if (!cpu_active(cpu_of(rq
)))
1068 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1071 static void hrtick_clear(struct rq
*rq
)
1073 if (hrtimer_active(&rq
->hrtick_timer
))
1074 hrtimer_cancel(&rq
->hrtick_timer
);
1078 * High-resolution timer tick.
1079 * Runs from hardirq context with interrupts disabled.
1081 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1083 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1085 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1087 spin_lock(&rq
->lock
);
1088 update_rq_clock(rq
);
1089 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1090 spin_unlock(&rq
->lock
);
1092 return HRTIMER_NORESTART
;
1097 * called from hardirq (IPI) context
1099 static void __hrtick_start(void *arg
)
1101 struct rq
*rq
= arg
;
1103 spin_lock(&rq
->lock
);
1104 hrtimer_restart(&rq
->hrtick_timer
);
1105 rq
->hrtick_csd_pending
= 0;
1106 spin_unlock(&rq
->lock
);
1110 * Called to set the hrtick timer state.
1112 * called with rq->lock held and irqs disabled
1114 static void hrtick_start(struct rq
*rq
, u64 delay
)
1116 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1117 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1119 hrtimer_set_expires(timer
, time
);
1121 if (rq
== this_rq()) {
1122 hrtimer_restart(timer
);
1123 } else if (!rq
->hrtick_csd_pending
) {
1124 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1125 rq
->hrtick_csd_pending
= 1;
1130 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1132 int cpu
= (int)(long)hcpu
;
1135 case CPU_UP_CANCELED
:
1136 case CPU_UP_CANCELED_FROZEN
:
1137 case CPU_DOWN_PREPARE
:
1138 case CPU_DOWN_PREPARE_FROZEN
:
1140 case CPU_DEAD_FROZEN
:
1141 hrtick_clear(cpu_rq(cpu
));
1148 static __init
void init_hrtick(void)
1150 hotcpu_notifier(hotplug_hrtick
, 0);
1154 * Called to set the hrtick timer state.
1156 * called with rq->lock held and irqs disabled
1158 static void hrtick_start(struct rq
*rq
, u64 delay
)
1160 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1161 HRTIMER_MODE_REL_PINNED
, 0);
1164 static inline void init_hrtick(void)
1167 #endif /* CONFIG_SMP */
1169 static void init_rq_hrtick(struct rq
*rq
)
1172 rq
->hrtick_csd_pending
= 0;
1174 rq
->hrtick_csd
.flags
= 0;
1175 rq
->hrtick_csd
.func
= __hrtick_start
;
1176 rq
->hrtick_csd
.info
= rq
;
1179 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1180 rq
->hrtick_timer
.function
= hrtick
;
1182 #else /* CONFIG_SCHED_HRTICK */
1183 static inline void hrtick_clear(struct rq
*rq
)
1187 static inline void init_rq_hrtick(struct rq
*rq
)
1191 static inline void init_hrtick(void)
1194 #endif /* CONFIG_SCHED_HRTICK */
1197 * resched_task - mark a task 'to be rescheduled now'.
1199 * On UP this means the setting of the need_resched flag, on SMP it
1200 * might also involve a cross-CPU call to trigger the scheduler on
1205 #ifndef tsk_is_polling
1206 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1209 static void resched_task(struct task_struct
*p
)
1213 assert_spin_locked(&task_rq(p
)->lock
);
1215 if (test_tsk_need_resched(p
))
1218 set_tsk_need_resched(p
);
1221 if (cpu
== smp_processor_id())
1224 /* NEED_RESCHED must be visible before we test polling */
1226 if (!tsk_is_polling(p
))
1227 smp_send_reschedule(cpu
);
1230 static void resched_cpu(int cpu
)
1232 struct rq
*rq
= cpu_rq(cpu
);
1233 unsigned long flags
;
1235 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1237 resched_task(cpu_curr(cpu
));
1238 spin_unlock_irqrestore(&rq
->lock
, flags
);
1243 * When add_timer_on() enqueues a timer into the timer wheel of an
1244 * idle CPU then this timer might expire before the next timer event
1245 * which is scheduled to wake up that CPU. In case of a completely
1246 * idle system the next event might even be infinite time into the
1247 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1248 * leaves the inner idle loop so the newly added timer is taken into
1249 * account when the CPU goes back to idle and evaluates the timer
1250 * wheel for the next timer event.
1252 void wake_up_idle_cpu(int cpu
)
1254 struct rq
*rq
= cpu_rq(cpu
);
1256 if (cpu
== smp_processor_id())
1260 * This is safe, as this function is called with the timer
1261 * wheel base lock of (cpu) held. When the CPU is on the way
1262 * to idle and has not yet set rq->curr to idle then it will
1263 * be serialized on the timer wheel base lock and take the new
1264 * timer into account automatically.
1266 if (rq
->curr
!= rq
->idle
)
1270 * We can set TIF_RESCHED on the idle task of the other CPU
1271 * lockless. The worst case is that the other CPU runs the
1272 * idle task through an additional NOOP schedule()
1274 set_tsk_need_resched(rq
->idle
);
1276 /* NEED_RESCHED must be visible before we test polling */
1278 if (!tsk_is_polling(rq
->idle
))
1279 smp_send_reschedule(cpu
);
1281 #endif /* CONFIG_NO_HZ */
1283 #else /* !CONFIG_SMP */
1284 static void resched_task(struct task_struct
*p
)
1286 assert_spin_locked(&task_rq(p
)->lock
);
1287 set_tsk_need_resched(p
);
1289 #endif /* CONFIG_SMP */
1291 #if BITS_PER_LONG == 32
1292 # define WMULT_CONST (~0UL)
1294 # define WMULT_CONST (1UL << 32)
1297 #define WMULT_SHIFT 32
1300 * Shift right and round:
1302 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1305 * delta *= weight / lw
1307 static unsigned long
1308 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1309 struct load_weight
*lw
)
1313 if (!lw
->inv_weight
) {
1314 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1317 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1321 tmp
= (u64
)delta_exec
* weight
;
1323 * Check whether we'd overflow the 64-bit multiplication:
1325 if (unlikely(tmp
> WMULT_CONST
))
1326 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1329 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1331 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1334 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1340 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1347 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1348 * of tasks with abnormal "nice" values across CPUs the contribution that
1349 * each task makes to its run queue's load is weighted according to its
1350 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1351 * scaled version of the new time slice allocation that they receive on time
1355 #define WEIGHT_IDLEPRIO 3
1356 #define WMULT_IDLEPRIO 1431655765
1359 * Nice levels are multiplicative, with a gentle 10% change for every
1360 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1361 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1362 * that remained on nice 0.
1364 * The "10% effect" is relative and cumulative: from _any_ nice level,
1365 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1366 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1367 * If a task goes up by ~10% and another task goes down by ~10% then
1368 * the relative distance between them is ~25%.)
1370 static const int prio_to_weight
[40] = {
1371 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1372 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1373 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1374 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1375 /* 0 */ 1024, 820, 655, 526, 423,
1376 /* 5 */ 335, 272, 215, 172, 137,
1377 /* 10 */ 110, 87, 70, 56, 45,
1378 /* 15 */ 36, 29, 23, 18, 15,
1382 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1384 * In cases where the weight does not change often, we can use the
1385 * precalculated inverse to speed up arithmetics by turning divisions
1386 * into multiplications:
1388 static const u32 prio_to_wmult
[40] = {
1389 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1390 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1391 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1392 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1393 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1394 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1395 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1396 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1399 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1402 * runqueue iterator, to support SMP load-balancing between different
1403 * scheduling classes, without having to expose their internal data
1404 * structures to the load-balancing proper:
1406 struct rq_iterator
{
1408 struct task_struct
*(*start
)(void *);
1409 struct task_struct
*(*next
)(void *);
1413 static unsigned long
1414 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1415 unsigned long max_load_move
, struct sched_domain
*sd
,
1416 enum cpu_idle_type idle
, int *all_pinned
,
1417 int *this_best_prio
, struct rq_iterator
*iterator
);
1420 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1421 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1422 struct rq_iterator
*iterator
);
1425 /* Time spent by the tasks of the cpu accounting group executing in ... */
1426 enum cpuacct_stat_index
{
1427 CPUACCT_STAT_USER
, /* ... user mode */
1428 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1430 CPUACCT_STAT_NSTATS
,
1433 #ifdef CONFIG_CGROUP_CPUACCT
1434 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1435 static void cpuacct_update_stats(struct task_struct
*tsk
,
1436 enum cpuacct_stat_index idx
, cputime_t val
);
1438 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1439 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1440 enum cpuacct_stat_index idx
, cputime_t val
) {}
1443 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1445 update_load_add(&rq
->load
, load
);
1448 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1450 update_load_sub(&rq
->load
, load
);
1453 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1454 typedef int (*tg_visitor
)(struct task_group
*, void *);
1457 * Iterate the full tree, calling @down when first entering a node and @up when
1458 * leaving it for the final time.
1460 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1462 struct task_group
*parent
, *child
;
1466 parent
= &root_task_group
;
1468 ret
= (*down
)(parent
, data
);
1471 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1478 ret
= (*up
)(parent
, data
);
1483 parent
= parent
->parent
;
1492 static int tg_nop(struct task_group
*tg
, void *data
)
1499 static unsigned long source_load(int cpu
, int type
);
1500 static unsigned long target_load(int cpu
, int type
);
1501 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1503 static unsigned long cpu_avg_load_per_task(int cpu
)
1505 struct rq
*rq
= cpu_rq(cpu
);
1506 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1509 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1511 rq
->avg_load_per_task
= 0;
1513 return rq
->avg_load_per_task
;
1516 #ifdef CONFIG_FAIR_GROUP_SCHED
1518 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1521 * Calculate and set the cpu's group shares.
1524 update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1525 unsigned long sd_shares
, unsigned long sd_rq_weight
)
1527 unsigned long rq_weight
;
1528 unsigned long shares
;
1534 rq_weight
= tg
->cfs_rq
[cpu
]->rq_weight
;
1537 rq_weight
= NICE_0_LOAD
;
1541 * \Sum shares * rq_weight
1542 * shares = -----------------------
1546 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1547 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1549 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1550 sysctl_sched_shares_thresh
) {
1551 struct rq
*rq
= cpu_rq(cpu
);
1552 unsigned long flags
;
1554 spin_lock_irqsave(&rq
->lock
, flags
);
1555 tg
->cfs_rq
[cpu
]->shares
= boost
? 0 : shares
;
1556 __set_se_shares(tg
->se
[cpu
], shares
);
1557 spin_unlock_irqrestore(&rq
->lock
, flags
);
1562 * Re-compute the task group their per cpu shares over the given domain.
1563 * This needs to be done in a bottom-up fashion because the rq weight of a
1564 * parent group depends on the shares of its child groups.
1566 static int tg_shares_up(struct task_group
*tg
, void *data
)
1568 unsigned long weight
, rq_weight
= 0, eff_weight
= 0;
1569 unsigned long shares
= 0;
1570 struct sched_domain
*sd
= data
;
1573 for_each_cpu(i
, sched_domain_span(sd
)) {
1575 * If there are currently no tasks on the cpu pretend there
1576 * is one of average load so that when a new task gets to
1577 * run here it will not get delayed by group starvation.
1579 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1580 tg
->cfs_rq
[i
]->rq_weight
= weight
;
1581 rq_weight
+= weight
;
1584 weight
= NICE_0_LOAD
;
1586 eff_weight
+= weight
;
1587 shares
+= tg
->cfs_rq
[i
]->shares
;
1590 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1591 shares
= tg
->shares
;
1593 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1594 shares
= tg
->shares
;
1596 for_each_cpu(i
, sched_domain_span(sd
)) {
1597 unsigned long sd_rq_weight
= rq_weight
;
1599 if (!tg
->cfs_rq
[i
]->rq_weight
)
1600 sd_rq_weight
= eff_weight
;
1602 update_group_shares_cpu(tg
, i
, shares
, sd_rq_weight
);
1609 * Compute the cpu's hierarchical load factor for each task group.
1610 * This needs to be done in a top-down fashion because the load of a child
1611 * group is a fraction of its parents load.
1613 static int tg_load_down(struct task_group
*tg
, void *data
)
1616 long cpu
= (long)data
;
1619 load
= cpu_rq(cpu
)->load
.weight
;
1621 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1622 load
*= tg
->cfs_rq
[cpu
]->shares
;
1623 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1626 tg
->cfs_rq
[cpu
]->h_load
= load
;
1631 static void update_shares(struct sched_domain
*sd
)
1636 if (root_task_group_empty())
1639 now
= cpu_clock(raw_smp_processor_id());
1640 elapsed
= now
- sd
->last_update
;
1642 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1643 sd
->last_update
= now
;
1644 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1648 static void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1650 if (root_task_group_empty())
1653 spin_unlock(&rq
->lock
);
1655 spin_lock(&rq
->lock
);
1658 static void update_h_load(long cpu
)
1660 if (root_task_group_empty())
1663 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1668 static inline void update_shares(struct sched_domain
*sd
)
1672 static inline void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1678 #ifdef CONFIG_PREEMPT
1681 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1682 * way at the expense of forcing extra atomic operations in all
1683 * invocations. This assures that the double_lock is acquired using the
1684 * same underlying policy as the spinlock_t on this architecture, which
1685 * reduces latency compared to the unfair variant below. However, it
1686 * also adds more overhead and therefore may reduce throughput.
1688 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1689 __releases(this_rq
->lock
)
1690 __acquires(busiest
->lock
)
1691 __acquires(this_rq
->lock
)
1693 spin_unlock(&this_rq
->lock
);
1694 double_rq_lock(this_rq
, busiest
);
1701 * Unfair double_lock_balance: Optimizes throughput at the expense of
1702 * latency by eliminating extra atomic operations when the locks are
1703 * already in proper order on entry. This favors lower cpu-ids and will
1704 * grant the double lock to lower cpus over higher ids under contention,
1705 * regardless of entry order into the function.
1707 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1708 __releases(this_rq
->lock
)
1709 __acquires(busiest
->lock
)
1710 __acquires(this_rq
->lock
)
1714 if (unlikely(!spin_trylock(&busiest
->lock
))) {
1715 if (busiest
< this_rq
) {
1716 spin_unlock(&this_rq
->lock
);
1717 spin_lock(&busiest
->lock
);
1718 spin_lock_nested(&this_rq
->lock
, SINGLE_DEPTH_NESTING
);
1721 spin_lock_nested(&busiest
->lock
, SINGLE_DEPTH_NESTING
);
1726 #endif /* CONFIG_PREEMPT */
1729 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1731 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1733 if (unlikely(!irqs_disabled())) {
1734 /* printk() doesn't work good under rq->lock */
1735 spin_unlock(&this_rq
->lock
);
1739 return _double_lock_balance(this_rq
, busiest
);
1742 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1743 __releases(busiest
->lock
)
1745 spin_unlock(&busiest
->lock
);
1746 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1750 #ifdef CONFIG_FAIR_GROUP_SCHED
1751 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1754 cfs_rq
->shares
= shares
;
1759 static void calc_load_account_active(struct rq
*this_rq
);
1761 #include "sched_stats.h"
1762 #include "sched_idletask.c"
1763 #include "sched_fair.c"
1764 #include "sched_rt.c"
1765 #ifdef CONFIG_SCHED_DEBUG
1766 # include "sched_debug.c"
1769 #define sched_class_highest (&rt_sched_class)
1770 #define for_each_class(class) \
1771 for (class = sched_class_highest; class; class = class->next)
1773 static void inc_nr_running(struct rq
*rq
)
1778 static void dec_nr_running(struct rq
*rq
)
1783 static void set_load_weight(struct task_struct
*p
)
1785 if (task_has_rt_policy(p
)) {
1786 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1787 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1792 * SCHED_IDLE tasks get minimal weight:
1794 if (p
->policy
== SCHED_IDLE
) {
1795 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1796 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1800 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1801 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1804 static void update_avg(u64
*avg
, u64 sample
)
1806 s64 diff
= sample
- *avg
;
1810 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1813 p
->se
.start_runtime
= p
->se
.sum_exec_runtime
;
1815 sched_info_queued(p
);
1816 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1820 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1823 if (p
->se
.last_wakeup
) {
1824 update_avg(&p
->se
.avg_overlap
,
1825 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1826 p
->se
.last_wakeup
= 0;
1828 update_avg(&p
->se
.avg_wakeup
,
1829 sysctl_sched_wakeup_granularity
);
1833 sched_info_dequeued(p
);
1834 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1839 * __normal_prio - return the priority that is based on the static prio
1841 static inline int __normal_prio(struct task_struct
*p
)
1843 return p
->static_prio
;
1847 * Calculate the expected normal priority: i.e. priority
1848 * without taking RT-inheritance into account. Might be
1849 * boosted by interactivity modifiers. Changes upon fork,
1850 * setprio syscalls, and whenever the interactivity
1851 * estimator recalculates.
1853 static inline int normal_prio(struct task_struct
*p
)
1857 if (task_has_rt_policy(p
))
1858 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1860 prio
= __normal_prio(p
);
1865 * Calculate the current priority, i.e. the priority
1866 * taken into account by the scheduler. This value might
1867 * be boosted by RT tasks, or might be boosted by
1868 * interactivity modifiers. Will be RT if the task got
1869 * RT-boosted. If not then it returns p->normal_prio.
1871 static int effective_prio(struct task_struct
*p
)
1873 p
->normal_prio
= normal_prio(p
);
1875 * If we are RT tasks or we were boosted to RT priority,
1876 * keep the priority unchanged. Otherwise, update priority
1877 * to the normal priority:
1879 if (!rt_prio(p
->prio
))
1880 return p
->normal_prio
;
1885 * activate_task - move a task to the runqueue.
1887 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1889 if (task_contributes_to_load(p
))
1890 rq
->nr_uninterruptible
--;
1892 enqueue_task(rq
, p
, wakeup
);
1897 * deactivate_task - remove a task from the runqueue.
1899 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1901 if (task_contributes_to_load(p
))
1902 rq
->nr_uninterruptible
++;
1904 dequeue_task(rq
, p
, sleep
);
1909 * task_curr - is this task currently executing on a CPU?
1910 * @p: the task in question.
1912 inline int task_curr(const struct task_struct
*p
)
1914 return cpu_curr(task_cpu(p
)) == p
;
1917 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1919 set_task_rq(p
, cpu
);
1922 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1923 * successfuly executed on another CPU. We must ensure that updates of
1924 * per-task data have been completed by this moment.
1927 task_thread_info(p
)->cpu
= cpu
;
1931 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1932 const struct sched_class
*prev_class
,
1933 int oldprio
, int running
)
1935 if (prev_class
!= p
->sched_class
) {
1936 if (prev_class
->switched_from
)
1937 prev_class
->switched_from(rq
, p
, running
);
1938 p
->sched_class
->switched_to(rq
, p
, running
);
1940 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1945 /* Used instead of source_load when we know the type == 0 */
1946 static unsigned long weighted_cpuload(const int cpu
)
1948 return cpu_rq(cpu
)->load
.weight
;
1952 * Is this task likely cache-hot:
1955 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1960 * Buddy candidates are cache hot:
1962 if (sched_feat(CACHE_HOT_BUDDY
) &&
1963 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
1964 &p
->se
== cfs_rq_of(&p
->se
)->last
))
1967 if (p
->sched_class
!= &fair_sched_class
)
1970 if (sysctl_sched_migration_cost
== -1)
1972 if (sysctl_sched_migration_cost
== 0)
1975 delta
= now
- p
->se
.exec_start
;
1977 return delta
< (s64
)sysctl_sched_migration_cost
;
1981 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1983 int old_cpu
= task_cpu(p
);
1984 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1985 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1986 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1989 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1991 trace_sched_migrate_task(p
, new_cpu
);
1993 #ifdef CONFIG_SCHEDSTATS
1994 if (p
->se
.wait_start
)
1995 p
->se
.wait_start
-= clock_offset
;
1996 if (p
->se
.sleep_start
)
1997 p
->se
.sleep_start
-= clock_offset
;
1998 if (p
->se
.block_start
)
1999 p
->se
.block_start
-= clock_offset
;
2001 if (old_cpu
!= new_cpu
) {
2002 p
->se
.nr_migrations
++;
2003 new_rq
->nr_migrations_in
++;
2004 #ifdef CONFIG_SCHEDSTATS
2005 if (task_hot(p
, old_rq
->clock
, NULL
))
2006 schedstat_inc(p
, se
.nr_forced2_migrations
);
2008 perf_swcounter_event(PERF_COUNT_SW_CPU_MIGRATIONS
,
2011 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
2012 new_cfsrq
->min_vruntime
;
2014 __set_task_cpu(p
, new_cpu
);
2017 struct migration_req
{
2018 struct list_head list
;
2020 struct task_struct
*task
;
2023 struct completion done
;
2027 * The task's runqueue lock must be held.
2028 * Returns true if you have to wait for migration thread.
2031 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
2033 struct rq
*rq
= task_rq(p
);
2036 * If the task is not on a runqueue (and not running), then
2037 * it is sufficient to simply update the task's cpu field.
2039 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
2040 set_task_cpu(p
, dest_cpu
);
2044 init_completion(&req
->done
);
2046 req
->dest_cpu
= dest_cpu
;
2047 list_add(&req
->list
, &rq
->migration_queue
);
2053 * wait_task_context_switch - wait for a thread to complete at least one
2056 * @p must not be current.
2058 void wait_task_context_switch(struct task_struct
*p
)
2060 unsigned long nvcsw
, nivcsw
, flags
;
2068 * The runqueue is assigned before the actual context
2069 * switch. We need to take the runqueue lock.
2071 * We could check initially without the lock but it is
2072 * very likely that we need to take the lock in every
2075 rq
= task_rq_lock(p
, &flags
);
2076 running
= task_running(rq
, p
);
2077 task_rq_unlock(rq
, &flags
);
2079 if (likely(!running
))
2082 * The switch count is incremented before the actual
2083 * context switch. We thus wait for two switches to be
2084 * sure at least one completed.
2086 if ((p
->nvcsw
- nvcsw
) > 1)
2088 if ((p
->nivcsw
- nivcsw
) > 1)
2096 * wait_task_inactive - wait for a thread to unschedule.
2098 * If @match_state is nonzero, it's the @p->state value just checked and
2099 * not expected to change. If it changes, i.e. @p might have woken up,
2100 * then return zero. When we succeed in waiting for @p to be off its CPU,
2101 * we return a positive number (its total switch count). If a second call
2102 * a short while later returns the same number, the caller can be sure that
2103 * @p has remained unscheduled the whole time.
2105 * The caller must ensure that the task *will* unschedule sometime soon,
2106 * else this function might spin for a *long* time. This function can't
2107 * be called with interrupts off, or it may introduce deadlock with
2108 * smp_call_function() if an IPI is sent by the same process we are
2109 * waiting to become inactive.
2111 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2113 unsigned long flags
;
2120 * We do the initial early heuristics without holding
2121 * any task-queue locks at all. We'll only try to get
2122 * the runqueue lock when things look like they will
2128 * If the task is actively running on another CPU
2129 * still, just relax and busy-wait without holding
2132 * NOTE! Since we don't hold any locks, it's not
2133 * even sure that "rq" stays as the right runqueue!
2134 * But we don't care, since "task_running()" will
2135 * return false if the runqueue has changed and p
2136 * is actually now running somewhere else!
2138 while (task_running(rq
, p
)) {
2139 if (match_state
&& unlikely(p
->state
!= match_state
))
2145 * Ok, time to look more closely! We need the rq
2146 * lock now, to be *sure*. If we're wrong, we'll
2147 * just go back and repeat.
2149 rq
= task_rq_lock(p
, &flags
);
2150 trace_sched_wait_task(rq
, p
);
2151 running
= task_running(rq
, p
);
2152 on_rq
= p
->se
.on_rq
;
2154 if (!match_state
|| p
->state
== match_state
)
2155 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2156 task_rq_unlock(rq
, &flags
);
2159 * If it changed from the expected state, bail out now.
2161 if (unlikely(!ncsw
))
2165 * Was it really running after all now that we
2166 * checked with the proper locks actually held?
2168 * Oops. Go back and try again..
2170 if (unlikely(running
)) {
2176 * It's not enough that it's not actively running,
2177 * it must be off the runqueue _entirely_, and not
2180 * So if it was still runnable (but just not actively
2181 * running right now), it's preempted, and we should
2182 * yield - it could be a while.
2184 if (unlikely(on_rq
)) {
2185 schedule_timeout_uninterruptible(1);
2190 * Ahh, all good. It wasn't running, and it wasn't
2191 * runnable, which means that it will never become
2192 * running in the future either. We're all done!
2201 * kick_process - kick a running thread to enter/exit the kernel
2202 * @p: the to-be-kicked thread
2204 * Cause a process which is running on another CPU to enter
2205 * kernel-mode, without any delay. (to get signals handled.)
2207 * NOTE: this function doesnt have to take the runqueue lock,
2208 * because all it wants to ensure is that the remote task enters
2209 * the kernel. If the IPI races and the task has been migrated
2210 * to another CPU then no harm is done and the purpose has been
2213 void kick_process(struct task_struct
*p
)
2219 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2220 smp_send_reschedule(cpu
);
2223 EXPORT_SYMBOL_GPL(kick_process
);
2226 * Return a low guess at the load of a migration-source cpu weighted
2227 * according to the scheduling class and "nice" value.
2229 * We want to under-estimate the load of migration sources, to
2230 * balance conservatively.
2232 static unsigned long source_load(int cpu
, int type
)
2234 struct rq
*rq
= cpu_rq(cpu
);
2235 unsigned long total
= weighted_cpuload(cpu
);
2237 if (type
== 0 || !sched_feat(LB_BIAS
))
2240 return min(rq
->cpu_load
[type
-1], total
);
2244 * Return a high guess at the load of a migration-target cpu weighted
2245 * according to the scheduling class and "nice" value.
2247 static unsigned long target_load(int cpu
, int type
)
2249 struct rq
*rq
= cpu_rq(cpu
);
2250 unsigned long total
= weighted_cpuload(cpu
);
2252 if (type
== 0 || !sched_feat(LB_BIAS
))
2255 return max(rq
->cpu_load
[type
-1], total
);
2259 * find_idlest_group finds and returns the least busy CPU group within the
2262 static struct sched_group
*
2263 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
2265 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2266 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
2267 int load_idx
= sd
->forkexec_idx
;
2268 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
2271 unsigned long load
, avg_load
;
2275 /* Skip over this group if it has no CPUs allowed */
2276 if (!cpumask_intersects(sched_group_cpus(group
),
2280 local_group
= cpumask_test_cpu(this_cpu
,
2281 sched_group_cpus(group
));
2283 /* Tally up the load of all CPUs in the group */
2286 for_each_cpu(i
, sched_group_cpus(group
)) {
2287 /* Bias balancing toward cpus of our domain */
2289 load
= source_load(i
, load_idx
);
2291 load
= target_load(i
, load_idx
);
2296 /* Adjust by relative CPU power of the group */
2297 avg_load
= sg_div_cpu_power(group
,
2298 avg_load
* SCHED_LOAD_SCALE
);
2301 this_load
= avg_load
;
2303 } else if (avg_load
< min_load
) {
2304 min_load
= avg_load
;
2307 } while (group
= group
->next
, group
!= sd
->groups
);
2309 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
2315 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2318 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
)
2320 unsigned long load
, min_load
= ULONG_MAX
;
2324 /* Traverse only the allowed CPUs */
2325 for_each_cpu_and(i
, sched_group_cpus(group
), &p
->cpus_allowed
) {
2326 load
= weighted_cpuload(i
);
2328 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
2338 * sched_balance_self: balance the current task (running on cpu) in domains
2339 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2342 * Balance, ie. select the least loaded group.
2344 * Returns the target CPU number, or the same CPU if no balancing is needed.
2346 * preempt must be disabled.
2348 static int sched_balance_self(int cpu
, int flag
)
2350 struct task_struct
*t
= current
;
2351 struct sched_domain
*tmp
, *sd
= NULL
;
2353 for_each_domain(cpu
, tmp
) {
2355 * If power savings logic is enabled for a domain, stop there.
2357 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2359 if (tmp
->flags
& flag
)
2367 struct sched_group
*group
;
2368 int new_cpu
, weight
;
2370 if (!(sd
->flags
& flag
)) {
2375 group
= find_idlest_group(sd
, t
, cpu
);
2381 new_cpu
= find_idlest_cpu(group
, t
, cpu
);
2382 if (new_cpu
== -1 || new_cpu
== cpu
) {
2383 /* Now try balancing at a lower domain level of cpu */
2388 /* Now try balancing at a lower domain level of new_cpu */
2390 weight
= cpumask_weight(sched_domain_span(sd
));
2392 for_each_domain(cpu
, tmp
) {
2393 if (weight
<= cpumask_weight(sched_domain_span(tmp
)))
2395 if (tmp
->flags
& flag
)
2398 /* while loop will break here if sd == NULL */
2404 #endif /* CONFIG_SMP */
2407 * task_oncpu_function_call - call a function on the cpu on which a task runs
2408 * @p: the task to evaluate
2409 * @func: the function to be called
2410 * @info: the function call argument
2412 * Calls the function @func when the task is currently running. This might
2413 * be on the current CPU, which just calls the function directly
2415 void task_oncpu_function_call(struct task_struct
*p
,
2416 void (*func
) (void *info
), void *info
)
2423 smp_call_function_single(cpu
, func
, info
, 1);
2428 * try_to_wake_up - wake up a thread
2429 * @p: the to-be-woken-up thread
2430 * @state: the mask of task states that can be woken
2431 * @sync: do a synchronous wakeup?
2433 * Put it on the run-queue if it's not already there. The "current"
2434 * thread is always on the run-queue (except when the actual
2435 * re-schedule is in progress), and as such you're allowed to do
2436 * the simpler "current->state = TASK_RUNNING" to mark yourself
2437 * runnable without the overhead of this.
2439 * returns failure only if the task is already active.
2441 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2443 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2444 unsigned long flags
;
2448 if (!sched_feat(SYNC_WAKEUPS
))
2452 if (sched_feat(LB_WAKEUP_UPDATE
) && !root_task_group_empty()) {
2453 struct sched_domain
*sd
;
2455 this_cpu
= raw_smp_processor_id();
2458 for_each_domain(this_cpu
, sd
) {
2459 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2468 rq
= task_rq_lock(p
, &flags
);
2469 update_rq_clock(rq
);
2470 old_state
= p
->state
;
2471 if (!(old_state
& state
))
2479 this_cpu
= smp_processor_id();
2482 if (unlikely(task_running(rq
, p
)))
2485 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2486 if (cpu
!= orig_cpu
) {
2487 set_task_cpu(p
, cpu
);
2488 task_rq_unlock(rq
, &flags
);
2489 /* might preempt at this point */
2490 rq
= task_rq_lock(p
, &flags
);
2491 old_state
= p
->state
;
2492 if (!(old_state
& state
))
2497 this_cpu
= smp_processor_id();
2501 #ifdef CONFIG_SCHEDSTATS
2502 schedstat_inc(rq
, ttwu_count
);
2503 if (cpu
== this_cpu
)
2504 schedstat_inc(rq
, ttwu_local
);
2506 struct sched_domain
*sd
;
2507 for_each_domain(this_cpu
, sd
) {
2508 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2509 schedstat_inc(sd
, ttwu_wake_remote
);
2514 #endif /* CONFIG_SCHEDSTATS */
2517 #endif /* CONFIG_SMP */
2518 schedstat_inc(p
, se
.nr_wakeups
);
2520 schedstat_inc(p
, se
.nr_wakeups_sync
);
2521 if (orig_cpu
!= cpu
)
2522 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2523 if (cpu
== this_cpu
)
2524 schedstat_inc(p
, se
.nr_wakeups_local
);
2526 schedstat_inc(p
, se
.nr_wakeups_remote
);
2527 activate_task(rq
, p
, 1);
2531 * Only attribute actual wakeups done by this task.
2533 if (!in_interrupt()) {
2534 struct sched_entity
*se
= ¤t
->se
;
2535 u64 sample
= se
->sum_exec_runtime
;
2537 if (se
->last_wakeup
)
2538 sample
-= se
->last_wakeup
;
2540 sample
-= se
->start_runtime
;
2541 update_avg(&se
->avg_wakeup
, sample
);
2543 se
->last_wakeup
= se
->sum_exec_runtime
;
2547 trace_sched_wakeup(rq
, p
, success
);
2548 check_preempt_curr(rq
, p
, sync
);
2550 p
->state
= TASK_RUNNING
;
2552 if (p
->sched_class
->task_wake_up
)
2553 p
->sched_class
->task_wake_up(rq
, p
);
2556 task_rq_unlock(rq
, &flags
);
2562 * wake_up_process - Wake up a specific process
2563 * @p: The process to be woken up.
2565 * Attempt to wake up the nominated process and move it to the set of runnable
2566 * processes. Returns 1 if the process was woken up, 0 if it was already
2569 * It may be assumed that this function implies a write memory barrier before
2570 * changing the task state if and only if any tasks are woken up.
2572 int wake_up_process(struct task_struct
*p
)
2574 return try_to_wake_up(p
, TASK_ALL
, 0);
2576 EXPORT_SYMBOL(wake_up_process
);
2578 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2580 return try_to_wake_up(p
, state
, 0);
2584 * Perform scheduler related setup for a newly forked process p.
2585 * p is forked by current.
2587 * __sched_fork() is basic setup used by init_idle() too:
2589 static void __sched_fork(struct task_struct
*p
)
2591 p
->se
.exec_start
= 0;
2592 p
->se
.sum_exec_runtime
= 0;
2593 p
->se
.prev_sum_exec_runtime
= 0;
2594 p
->se
.nr_migrations
= 0;
2595 p
->se
.last_wakeup
= 0;
2596 p
->se
.avg_overlap
= 0;
2597 p
->se
.start_runtime
= 0;
2598 p
->se
.avg_wakeup
= sysctl_sched_wakeup_granularity
;
2600 #ifdef CONFIG_SCHEDSTATS
2601 p
->se
.wait_start
= 0;
2603 p
->se
.wait_count
= 0;
2606 p
->se
.sleep_start
= 0;
2607 p
->se
.sleep_max
= 0;
2608 p
->se
.sum_sleep_runtime
= 0;
2610 p
->se
.block_start
= 0;
2611 p
->se
.block_max
= 0;
2613 p
->se
.slice_max
= 0;
2615 p
->se
.nr_migrations_cold
= 0;
2616 p
->se
.nr_failed_migrations_affine
= 0;
2617 p
->se
.nr_failed_migrations_running
= 0;
2618 p
->se
.nr_failed_migrations_hot
= 0;
2619 p
->se
.nr_forced_migrations
= 0;
2620 p
->se
.nr_forced2_migrations
= 0;
2622 p
->se
.nr_wakeups
= 0;
2623 p
->se
.nr_wakeups_sync
= 0;
2624 p
->se
.nr_wakeups_migrate
= 0;
2625 p
->se
.nr_wakeups_local
= 0;
2626 p
->se
.nr_wakeups_remote
= 0;
2627 p
->se
.nr_wakeups_affine
= 0;
2628 p
->se
.nr_wakeups_affine_attempts
= 0;
2629 p
->se
.nr_wakeups_passive
= 0;
2630 p
->se
.nr_wakeups_idle
= 0;
2634 INIT_LIST_HEAD(&p
->rt
.run_list
);
2636 INIT_LIST_HEAD(&p
->se
.group_node
);
2638 #ifdef CONFIG_PREEMPT_NOTIFIERS
2639 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2643 * We mark the process as running here, but have not actually
2644 * inserted it onto the runqueue yet. This guarantees that
2645 * nobody will actually run it, and a signal or other external
2646 * event cannot wake it up and insert it on the runqueue either.
2648 p
->state
= TASK_RUNNING
;
2652 * fork()/clone()-time setup:
2654 void sched_fork(struct task_struct
*p
, int clone_flags
)
2656 int cpu
= get_cpu();
2661 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2663 set_task_cpu(p
, cpu
);
2666 * Make sure we do not leak PI boosting priority to the child.
2668 p
->prio
= current
->normal_prio
;
2671 * Revert to default priority/policy on fork if requested.
2673 if (unlikely(p
->sched_reset_on_fork
)) {
2674 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
)
2675 p
->policy
= SCHED_NORMAL
;
2677 if (p
->normal_prio
< DEFAULT_PRIO
)
2678 p
->prio
= DEFAULT_PRIO
;
2680 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2681 p
->static_prio
= NICE_TO_PRIO(0);
2686 * We don't need the reset flag anymore after the fork. It has
2687 * fulfilled its duty:
2689 p
->sched_reset_on_fork
= 0;
2692 if (!rt_prio(p
->prio
))
2693 p
->sched_class
= &fair_sched_class
;
2695 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2696 if (likely(sched_info_on()))
2697 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2699 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2702 #ifdef CONFIG_PREEMPT
2703 /* Want to start with kernel preemption disabled. */
2704 task_thread_info(p
)->preempt_count
= 1;
2706 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2712 * wake_up_new_task - wake up a newly created task for the first time.
2714 * This function will do some initial scheduler statistics housekeeping
2715 * that must be done for every newly created context, then puts the task
2716 * on the runqueue and wakes it.
2718 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2720 unsigned long flags
;
2723 rq
= task_rq_lock(p
, &flags
);
2724 BUG_ON(p
->state
!= TASK_RUNNING
);
2725 update_rq_clock(rq
);
2727 p
->prio
= effective_prio(p
);
2729 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2730 activate_task(rq
, p
, 0);
2733 * Let the scheduling class do new task startup
2734 * management (if any):
2736 p
->sched_class
->task_new(rq
, p
);
2739 trace_sched_wakeup_new(rq
, p
, 1);
2740 check_preempt_curr(rq
, p
, 0);
2742 if (p
->sched_class
->task_wake_up
)
2743 p
->sched_class
->task_wake_up(rq
, p
);
2745 task_rq_unlock(rq
, &flags
);
2748 #ifdef CONFIG_PREEMPT_NOTIFIERS
2751 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2752 * @notifier: notifier struct to register
2754 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2756 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2758 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2761 * preempt_notifier_unregister - no longer interested in preemption notifications
2762 * @notifier: notifier struct to unregister
2764 * This is safe to call from within a preemption notifier.
2766 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2768 hlist_del(¬ifier
->link
);
2770 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2772 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2774 struct preempt_notifier
*notifier
;
2775 struct hlist_node
*node
;
2777 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2778 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2782 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2783 struct task_struct
*next
)
2785 struct preempt_notifier
*notifier
;
2786 struct hlist_node
*node
;
2788 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2789 notifier
->ops
->sched_out(notifier
, next
);
2792 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2794 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2799 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2800 struct task_struct
*next
)
2804 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2807 * prepare_task_switch - prepare to switch tasks
2808 * @rq: the runqueue preparing to switch
2809 * @prev: the current task that is being switched out
2810 * @next: the task we are going to switch to.
2812 * This is called with the rq lock held and interrupts off. It must
2813 * be paired with a subsequent finish_task_switch after the context
2816 * prepare_task_switch sets up locking and calls architecture specific
2820 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2821 struct task_struct
*next
)
2823 fire_sched_out_preempt_notifiers(prev
, next
);
2824 prepare_lock_switch(rq
, next
);
2825 prepare_arch_switch(next
);
2829 * finish_task_switch - clean up after a task-switch
2830 * @rq: runqueue associated with task-switch
2831 * @prev: the thread we just switched away from.
2833 * finish_task_switch must be called after the context switch, paired
2834 * with a prepare_task_switch call before the context switch.
2835 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2836 * and do any other architecture-specific cleanup actions.
2838 * Note that we may have delayed dropping an mm in context_switch(). If
2839 * so, we finish that here outside of the runqueue lock. (Doing it
2840 * with the lock held can cause deadlocks; see schedule() for
2843 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2844 __releases(rq
->lock
)
2846 struct mm_struct
*mm
= rq
->prev_mm
;
2852 * A task struct has one reference for the use as "current".
2853 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2854 * schedule one last time. The schedule call will never return, and
2855 * the scheduled task must drop that reference.
2856 * The test for TASK_DEAD must occur while the runqueue locks are
2857 * still held, otherwise prev could be scheduled on another cpu, die
2858 * there before we look at prev->state, and then the reference would
2860 * Manfred Spraul <manfred@colorfullife.com>
2862 prev_state
= prev
->state
;
2863 finish_arch_switch(prev
);
2864 perf_counter_task_sched_in(current
, cpu_of(rq
));
2865 finish_lock_switch(rq
, prev
);
2867 fire_sched_in_preempt_notifiers(current
);
2870 if (unlikely(prev_state
== TASK_DEAD
)) {
2872 * Remove function-return probe instances associated with this
2873 * task and put them back on the free list.
2875 kprobe_flush_task(prev
);
2876 put_task_struct(prev
);
2882 /* assumes rq->lock is held */
2883 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2885 if (prev
->sched_class
->pre_schedule
)
2886 prev
->sched_class
->pre_schedule(rq
, prev
);
2889 /* rq->lock is NOT held, but preemption is disabled */
2890 static inline void post_schedule(struct rq
*rq
)
2892 if (rq
->post_schedule
) {
2893 unsigned long flags
;
2895 spin_lock_irqsave(&rq
->lock
, flags
);
2896 if (rq
->curr
->sched_class
->post_schedule
)
2897 rq
->curr
->sched_class
->post_schedule(rq
);
2898 spin_unlock_irqrestore(&rq
->lock
, flags
);
2900 rq
->post_schedule
= 0;
2906 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2910 static inline void post_schedule(struct rq
*rq
)
2917 * schedule_tail - first thing a freshly forked thread must call.
2918 * @prev: the thread we just switched away from.
2920 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2921 __releases(rq
->lock
)
2923 struct rq
*rq
= this_rq();
2925 finish_task_switch(rq
, prev
);
2928 * FIXME: do we need to worry about rq being invalidated by the
2933 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2934 /* In this case, finish_task_switch does not reenable preemption */
2937 if (current
->set_child_tid
)
2938 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2942 * context_switch - switch to the new MM and the new
2943 * thread's register state.
2946 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2947 struct task_struct
*next
)
2949 struct mm_struct
*mm
, *oldmm
;
2951 prepare_task_switch(rq
, prev
, next
);
2952 trace_sched_switch(rq
, prev
, next
);
2954 oldmm
= prev
->active_mm
;
2956 * For paravirt, this is coupled with an exit in switch_to to
2957 * combine the page table reload and the switch backend into
2960 arch_start_context_switch(prev
);
2962 if (unlikely(!mm
)) {
2963 next
->active_mm
= oldmm
;
2964 atomic_inc(&oldmm
->mm_count
);
2965 enter_lazy_tlb(oldmm
, next
);
2967 switch_mm(oldmm
, mm
, next
);
2969 if (unlikely(!prev
->mm
)) {
2970 prev
->active_mm
= NULL
;
2971 rq
->prev_mm
= oldmm
;
2974 * Since the runqueue lock will be released by the next
2975 * task (which is an invalid locking op but in the case
2976 * of the scheduler it's an obvious special-case), so we
2977 * do an early lockdep release here:
2979 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2980 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2983 /* Here we just switch the register state and the stack. */
2984 switch_to(prev
, next
, prev
);
2988 * this_rq must be evaluated again because prev may have moved
2989 * CPUs since it called schedule(), thus the 'rq' on its stack
2990 * frame will be invalid.
2992 finish_task_switch(this_rq(), prev
);
2996 * nr_running, nr_uninterruptible and nr_context_switches:
2998 * externally visible scheduler statistics: current number of runnable
2999 * threads, current number of uninterruptible-sleeping threads, total
3000 * number of context switches performed since bootup.
3002 unsigned long nr_running(void)
3004 unsigned long i
, sum
= 0;
3006 for_each_online_cpu(i
)
3007 sum
+= cpu_rq(i
)->nr_running
;
3012 unsigned long nr_uninterruptible(void)
3014 unsigned long i
, sum
= 0;
3016 for_each_possible_cpu(i
)
3017 sum
+= cpu_rq(i
)->nr_uninterruptible
;
3020 * Since we read the counters lockless, it might be slightly
3021 * inaccurate. Do not allow it to go below zero though:
3023 if (unlikely((long)sum
< 0))
3029 unsigned long long nr_context_switches(void)
3032 unsigned long long sum
= 0;
3034 for_each_possible_cpu(i
)
3035 sum
+= cpu_rq(i
)->nr_switches
;
3040 unsigned long nr_iowait(void)
3042 unsigned long i
, sum
= 0;
3044 for_each_possible_cpu(i
)
3045 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
3050 /* Variables and functions for calc_load */
3051 static atomic_long_t calc_load_tasks
;
3052 static unsigned long calc_load_update
;
3053 unsigned long avenrun
[3];
3054 EXPORT_SYMBOL(avenrun
);
3057 * get_avenrun - get the load average array
3058 * @loads: pointer to dest load array
3059 * @offset: offset to add
3060 * @shift: shift count to shift the result left
3062 * These values are estimates at best, so no need for locking.
3064 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
3066 loads
[0] = (avenrun
[0] + offset
) << shift
;
3067 loads
[1] = (avenrun
[1] + offset
) << shift
;
3068 loads
[2] = (avenrun
[2] + offset
) << shift
;
3071 static unsigned long
3072 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
3075 load
+= active
* (FIXED_1
- exp
);
3076 return load
>> FSHIFT
;
3080 * calc_load - update the avenrun load estimates 10 ticks after the
3081 * CPUs have updated calc_load_tasks.
3083 void calc_global_load(void)
3085 unsigned long upd
= calc_load_update
+ 10;
3088 if (time_before(jiffies
, upd
))
3091 active
= atomic_long_read(&calc_load_tasks
);
3092 active
= active
> 0 ? active
* FIXED_1
: 0;
3094 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3095 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3096 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3098 calc_load_update
+= LOAD_FREQ
;
3102 * Either called from update_cpu_load() or from a cpu going idle
3104 static void calc_load_account_active(struct rq
*this_rq
)
3106 long nr_active
, delta
;
3108 nr_active
= this_rq
->nr_running
;
3109 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3111 if (nr_active
!= this_rq
->calc_load_active
) {
3112 delta
= nr_active
- this_rq
->calc_load_active
;
3113 this_rq
->calc_load_active
= nr_active
;
3114 atomic_long_add(delta
, &calc_load_tasks
);
3119 * Externally visible per-cpu scheduler statistics:
3120 * cpu_nr_migrations(cpu) - number of migrations into that cpu
3122 u64
cpu_nr_migrations(int cpu
)
3124 return cpu_rq(cpu
)->nr_migrations_in
;
3128 * Update rq->cpu_load[] statistics. This function is usually called every
3129 * scheduler tick (TICK_NSEC).
3131 static void update_cpu_load(struct rq
*this_rq
)
3133 unsigned long this_load
= this_rq
->load
.weight
;
3136 this_rq
->nr_load_updates
++;
3138 /* Update our load: */
3139 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3140 unsigned long old_load
, new_load
;
3142 /* scale is effectively 1 << i now, and >> i divides by scale */
3144 old_load
= this_rq
->cpu_load
[i
];
3145 new_load
= this_load
;
3147 * Round up the averaging division if load is increasing. This
3148 * prevents us from getting stuck on 9 if the load is 10, for
3151 if (new_load
> old_load
)
3152 new_load
+= scale
-1;
3153 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
3156 if (time_after_eq(jiffies
, this_rq
->calc_load_update
)) {
3157 this_rq
->calc_load_update
+= LOAD_FREQ
;
3158 calc_load_account_active(this_rq
);
3165 * double_rq_lock - safely lock two runqueues
3167 * Note this does not disable interrupts like task_rq_lock,
3168 * you need to do so manually before calling.
3170 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
3171 __acquires(rq1
->lock
)
3172 __acquires(rq2
->lock
)
3174 BUG_ON(!irqs_disabled());
3176 spin_lock(&rq1
->lock
);
3177 __acquire(rq2
->lock
); /* Fake it out ;) */
3180 spin_lock(&rq1
->lock
);
3181 spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
3183 spin_lock(&rq2
->lock
);
3184 spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
3187 update_rq_clock(rq1
);
3188 update_rq_clock(rq2
);
3192 * double_rq_unlock - safely unlock two runqueues
3194 * Note this does not restore interrupts like task_rq_unlock,
3195 * you need to do so manually after calling.
3197 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
3198 __releases(rq1
->lock
)
3199 __releases(rq2
->lock
)
3201 spin_unlock(&rq1
->lock
);
3203 spin_unlock(&rq2
->lock
);
3205 __release(rq2
->lock
);
3209 * If dest_cpu is allowed for this process, migrate the task to it.
3210 * This is accomplished by forcing the cpu_allowed mask to only
3211 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
3212 * the cpu_allowed mask is restored.
3214 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
3216 struct migration_req req
;
3217 unsigned long flags
;
3220 rq
= task_rq_lock(p
, &flags
);
3221 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
3222 || unlikely(!cpu_active(dest_cpu
)))
3225 /* force the process onto the specified CPU */
3226 if (migrate_task(p
, dest_cpu
, &req
)) {
3227 /* Need to wait for migration thread (might exit: take ref). */
3228 struct task_struct
*mt
= rq
->migration_thread
;
3230 get_task_struct(mt
);
3231 task_rq_unlock(rq
, &flags
);
3232 wake_up_process(mt
);
3233 put_task_struct(mt
);
3234 wait_for_completion(&req
.done
);
3239 task_rq_unlock(rq
, &flags
);
3243 * sched_exec - execve() is a valuable balancing opportunity, because at
3244 * this point the task has the smallest effective memory and cache footprint.
3246 void sched_exec(void)
3248 int new_cpu
, this_cpu
= get_cpu();
3249 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
3251 if (new_cpu
!= this_cpu
)
3252 sched_migrate_task(current
, new_cpu
);
3256 * pull_task - move a task from a remote runqueue to the local runqueue.
3257 * Both runqueues must be locked.
3259 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
3260 struct rq
*this_rq
, int this_cpu
)
3262 deactivate_task(src_rq
, p
, 0);
3263 set_task_cpu(p
, this_cpu
);
3264 activate_task(this_rq
, p
, 0);
3266 * Note that idle threads have a prio of MAX_PRIO, for this test
3267 * to be always true for them.
3269 check_preempt_curr(this_rq
, p
, 0);
3273 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3276 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
3277 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3280 int tsk_cache_hot
= 0;
3282 * We do not migrate tasks that are:
3283 * 1) running (obviously), or
3284 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3285 * 3) are cache-hot on their current CPU.
3287 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
3288 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3293 if (task_running(rq
, p
)) {
3294 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3299 * Aggressive migration if:
3300 * 1) task is cache cold, or
3301 * 2) too many balance attempts have failed.
3304 tsk_cache_hot
= task_hot(p
, rq
->clock
, sd
);
3305 if (!tsk_cache_hot
||
3306 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3307 #ifdef CONFIG_SCHEDSTATS
3308 if (tsk_cache_hot
) {
3309 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3310 schedstat_inc(p
, se
.nr_forced_migrations
);
3316 if (tsk_cache_hot
) {
3317 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3323 static unsigned long
3324 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3325 unsigned long max_load_move
, struct sched_domain
*sd
,
3326 enum cpu_idle_type idle
, int *all_pinned
,
3327 int *this_best_prio
, struct rq_iterator
*iterator
)
3329 int loops
= 0, pulled
= 0, pinned
= 0;
3330 struct task_struct
*p
;
3331 long rem_load_move
= max_load_move
;
3333 if (max_load_move
== 0)
3339 * Start the load-balancing iterator:
3341 p
= iterator
->start(iterator
->arg
);
3343 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3346 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3347 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3348 p
= iterator
->next(iterator
->arg
);
3352 pull_task(busiest
, p
, this_rq
, this_cpu
);
3354 rem_load_move
-= p
->se
.load
.weight
;
3356 #ifdef CONFIG_PREEMPT
3358 * NEWIDLE balancing is a source of latency, so preemptible kernels
3359 * will stop after the first task is pulled to minimize the critical
3362 if (idle
== CPU_NEWLY_IDLE
)
3367 * We only want to steal up to the prescribed amount of weighted load.
3369 if (rem_load_move
> 0) {
3370 if (p
->prio
< *this_best_prio
)
3371 *this_best_prio
= p
->prio
;
3372 p
= iterator
->next(iterator
->arg
);
3377 * Right now, this is one of only two places pull_task() is called,
3378 * so we can safely collect pull_task() stats here rather than
3379 * inside pull_task().
3381 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3384 *all_pinned
= pinned
;
3386 return max_load_move
- rem_load_move
;
3390 * move_tasks tries to move up to max_load_move weighted load from busiest to
3391 * this_rq, as part of a balancing operation within domain "sd".
3392 * Returns 1 if successful and 0 otherwise.
3394 * Called with both runqueues locked.
3396 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3397 unsigned long max_load_move
,
3398 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3401 const struct sched_class
*class = sched_class_highest
;
3402 unsigned long total_load_moved
= 0;
3403 int this_best_prio
= this_rq
->curr
->prio
;
3407 class->load_balance(this_rq
, this_cpu
, busiest
,
3408 max_load_move
- total_load_moved
,
3409 sd
, idle
, all_pinned
, &this_best_prio
);
3410 class = class->next
;
3412 #ifdef CONFIG_PREEMPT
3414 * NEWIDLE balancing is a source of latency, so preemptible
3415 * kernels will stop after the first task is pulled to minimize
3416 * the critical section.
3418 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3421 } while (class && max_load_move
> total_load_moved
);
3423 return total_load_moved
> 0;
3427 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3428 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3429 struct rq_iterator
*iterator
)
3431 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3435 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3436 pull_task(busiest
, p
, this_rq
, this_cpu
);
3438 * Right now, this is only the second place pull_task()
3439 * is called, so we can safely collect pull_task()
3440 * stats here rather than inside pull_task().
3442 schedstat_inc(sd
, lb_gained
[idle
]);
3446 p
= iterator
->next(iterator
->arg
);
3453 * move_one_task tries to move exactly one task from busiest to this_rq, as
3454 * part of active balancing operations within "domain".
3455 * Returns 1 if successful and 0 otherwise.
3457 * Called with both runqueues locked.
3459 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3460 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3462 const struct sched_class
*class;
3464 for_each_class(class) {
3465 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3471 /********** Helpers for find_busiest_group ************************/
3473 * sd_lb_stats - Structure to store the statistics of a sched_domain
3474 * during load balancing.
3476 struct sd_lb_stats
{
3477 struct sched_group
*busiest
; /* Busiest group in this sd */
3478 struct sched_group
*this; /* Local group in this sd */
3479 unsigned long total_load
; /* Total load of all groups in sd */
3480 unsigned long total_pwr
; /* Total power of all groups in sd */
3481 unsigned long avg_load
; /* Average load across all groups in sd */
3483 /** Statistics of this group */
3484 unsigned long this_load
;
3485 unsigned long this_load_per_task
;
3486 unsigned long this_nr_running
;
3488 /* Statistics of the busiest group */
3489 unsigned long max_load
;
3490 unsigned long busiest_load_per_task
;
3491 unsigned long busiest_nr_running
;
3493 int group_imb
; /* Is there imbalance in this sd */
3494 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3495 int power_savings_balance
; /* Is powersave balance needed for this sd */
3496 struct sched_group
*group_min
; /* Least loaded group in sd */
3497 struct sched_group
*group_leader
; /* Group which relieves group_min */
3498 unsigned long min_load_per_task
; /* load_per_task in group_min */
3499 unsigned long leader_nr_running
; /* Nr running of group_leader */
3500 unsigned long min_nr_running
; /* Nr running of group_min */
3505 * sg_lb_stats - stats of a sched_group required for load_balancing
3507 struct sg_lb_stats
{
3508 unsigned long avg_load
; /*Avg load across the CPUs of the group */
3509 unsigned long group_load
; /* Total load over the CPUs of the group */
3510 unsigned long sum_nr_running
; /* Nr tasks running in the group */
3511 unsigned long sum_weighted_load
; /* Weighted load of group's tasks */
3512 unsigned long group_capacity
;
3513 int group_imb
; /* Is there an imbalance in the group ? */
3517 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3518 * @group: The group whose first cpu is to be returned.
3520 static inline unsigned int group_first_cpu(struct sched_group
*group
)
3522 return cpumask_first(sched_group_cpus(group
));
3526 * get_sd_load_idx - Obtain the load index for a given sched domain.
3527 * @sd: The sched_domain whose load_idx is to be obtained.
3528 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3530 static inline int get_sd_load_idx(struct sched_domain
*sd
,
3531 enum cpu_idle_type idle
)
3537 load_idx
= sd
->busy_idx
;
3540 case CPU_NEWLY_IDLE
:
3541 load_idx
= sd
->newidle_idx
;
3544 load_idx
= sd
->idle_idx
;
3552 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3554 * init_sd_power_savings_stats - Initialize power savings statistics for
3555 * the given sched_domain, during load balancing.
3557 * @sd: Sched domain whose power-savings statistics are to be initialized.
3558 * @sds: Variable containing the statistics for sd.
3559 * @idle: Idle status of the CPU at which we're performing load-balancing.
3561 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3562 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3565 * Busy processors will not participate in power savings
3568 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3569 sds
->power_savings_balance
= 0;
3571 sds
->power_savings_balance
= 1;
3572 sds
->min_nr_running
= ULONG_MAX
;
3573 sds
->leader_nr_running
= 0;
3578 * update_sd_power_savings_stats - Update the power saving stats for a
3579 * sched_domain while performing load balancing.
3581 * @group: sched_group belonging to the sched_domain under consideration.
3582 * @sds: Variable containing the statistics of the sched_domain
3583 * @local_group: Does group contain the CPU for which we're performing
3585 * @sgs: Variable containing the statistics of the group.
3587 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3588 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3591 if (!sds
->power_savings_balance
)
3595 * If the local group is idle or completely loaded
3596 * no need to do power savings balance at this domain
3598 if (local_group
&& (sds
->this_nr_running
>= sgs
->group_capacity
||
3599 !sds
->this_nr_running
))
3600 sds
->power_savings_balance
= 0;
3603 * If a group is already running at full capacity or idle,
3604 * don't include that group in power savings calculations
3606 if (!sds
->power_savings_balance
||
3607 sgs
->sum_nr_running
>= sgs
->group_capacity
||
3608 !sgs
->sum_nr_running
)
3612 * Calculate the group which has the least non-idle load.
3613 * This is the group from where we need to pick up the load
3616 if ((sgs
->sum_nr_running
< sds
->min_nr_running
) ||
3617 (sgs
->sum_nr_running
== sds
->min_nr_running
&&
3618 group_first_cpu(group
) > group_first_cpu(sds
->group_min
))) {
3619 sds
->group_min
= group
;
3620 sds
->min_nr_running
= sgs
->sum_nr_running
;
3621 sds
->min_load_per_task
= sgs
->sum_weighted_load
/
3622 sgs
->sum_nr_running
;
3626 * Calculate the group which is almost near its
3627 * capacity but still has some space to pick up some load
3628 * from other group and save more power
3630 if (sgs
->sum_nr_running
> sgs
->group_capacity
- 1)
3633 if (sgs
->sum_nr_running
> sds
->leader_nr_running
||
3634 (sgs
->sum_nr_running
== sds
->leader_nr_running
&&
3635 group_first_cpu(group
) < group_first_cpu(sds
->group_leader
))) {
3636 sds
->group_leader
= group
;
3637 sds
->leader_nr_running
= sgs
->sum_nr_running
;
3642 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3643 * @sds: Variable containing the statistics of the sched_domain
3644 * under consideration.
3645 * @this_cpu: Cpu at which we're currently performing load-balancing.
3646 * @imbalance: Variable to store the imbalance.
3649 * Check if we have potential to perform some power-savings balance.
3650 * If yes, set the busiest group to be the least loaded group in the
3651 * sched_domain, so that it's CPUs can be put to idle.
3653 * Returns 1 if there is potential to perform power-savings balance.
3656 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3657 int this_cpu
, unsigned long *imbalance
)
3659 if (!sds
->power_savings_balance
)
3662 if (sds
->this != sds
->group_leader
||
3663 sds
->group_leader
== sds
->group_min
)
3666 *imbalance
= sds
->min_load_per_task
;
3667 sds
->busiest
= sds
->group_min
;
3669 if (sched_mc_power_savings
>= POWERSAVINGS_BALANCE_WAKEUP
) {
3670 cpu_rq(this_cpu
)->rd
->sched_mc_preferred_wakeup_cpu
=
3671 group_first_cpu(sds
->group_leader
);
3677 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3678 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3679 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3684 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3685 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3690 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3691 int this_cpu
, unsigned long *imbalance
)
3695 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3699 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3700 * @group: sched_group whose statistics are to be updated.
3701 * @this_cpu: Cpu for which load balance is currently performed.
3702 * @idle: Idle status of this_cpu
3703 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3704 * @sd_idle: Idle status of the sched_domain containing group.
3705 * @local_group: Does group contain this_cpu.
3706 * @cpus: Set of cpus considered for load balancing.
3707 * @balance: Should we balance.
3708 * @sgs: variable to hold the statistics for this group.
3710 static inline void update_sg_lb_stats(struct sched_group
*group
, int this_cpu
,
3711 enum cpu_idle_type idle
, int load_idx
, int *sd_idle
,
3712 int local_group
, const struct cpumask
*cpus
,
3713 int *balance
, struct sg_lb_stats
*sgs
)
3715 unsigned long load
, max_cpu_load
, min_cpu_load
;
3717 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3718 unsigned long sum_avg_load_per_task
;
3719 unsigned long avg_load_per_task
;
3722 balance_cpu
= group_first_cpu(group
);
3724 /* Tally up the load of all CPUs in the group */
3725 sum_avg_load_per_task
= avg_load_per_task
= 0;
3727 min_cpu_load
= ~0UL;
3729 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3730 struct rq
*rq
= cpu_rq(i
);
3732 if (*sd_idle
&& rq
->nr_running
)
3735 /* Bias balancing toward cpus of our domain */
3737 if (idle_cpu(i
) && !first_idle_cpu
) {
3742 load
= target_load(i
, load_idx
);
3744 load
= source_load(i
, load_idx
);
3745 if (load
> max_cpu_load
)
3746 max_cpu_load
= load
;
3747 if (min_cpu_load
> load
)
3748 min_cpu_load
= load
;
3751 sgs
->group_load
+= load
;
3752 sgs
->sum_nr_running
+= rq
->nr_running
;
3753 sgs
->sum_weighted_load
+= weighted_cpuload(i
);
3755 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3759 * First idle cpu or the first cpu(busiest) in this sched group
3760 * is eligible for doing load balancing at this and above
3761 * domains. In the newly idle case, we will allow all the cpu's
3762 * to do the newly idle load balance.
3764 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3765 balance_cpu
!= this_cpu
&& balance
) {
3770 /* Adjust by relative CPU power of the group */
3771 sgs
->avg_load
= sg_div_cpu_power(group
,
3772 sgs
->group_load
* SCHED_LOAD_SCALE
);
3776 * Consider the group unbalanced when the imbalance is larger
3777 * than the average weight of two tasks.
3779 * APZ: with cgroup the avg task weight can vary wildly and
3780 * might not be a suitable number - should we keep a
3781 * normalized nr_running number somewhere that negates
3784 avg_load_per_task
= sg_div_cpu_power(group
,
3785 sum_avg_load_per_task
* SCHED_LOAD_SCALE
);
3787 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3790 sgs
->group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3795 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3796 * @sd: sched_domain whose statistics are to be updated.
3797 * @this_cpu: Cpu for which load balance is currently performed.
3798 * @idle: Idle status of this_cpu
3799 * @sd_idle: Idle status of the sched_domain containing group.
3800 * @cpus: Set of cpus considered for load balancing.
3801 * @balance: Should we balance.
3802 * @sds: variable to hold the statistics for this sched_domain.
3804 static inline void update_sd_lb_stats(struct sched_domain
*sd
, int this_cpu
,
3805 enum cpu_idle_type idle
, int *sd_idle
,
3806 const struct cpumask
*cpus
, int *balance
,
3807 struct sd_lb_stats
*sds
)
3809 struct sched_group
*group
= sd
->groups
;
3810 struct sg_lb_stats sgs
;
3813 init_sd_power_savings_stats(sd
, sds
, idle
);
3814 load_idx
= get_sd_load_idx(sd
, idle
);
3819 local_group
= cpumask_test_cpu(this_cpu
,
3820 sched_group_cpus(group
));
3821 memset(&sgs
, 0, sizeof(sgs
));
3822 update_sg_lb_stats(group
, this_cpu
, idle
, load_idx
, sd_idle
,
3823 local_group
, cpus
, balance
, &sgs
);
3825 if (local_group
&& balance
&& !(*balance
))
3828 sds
->total_load
+= sgs
.group_load
;
3829 sds
->total_pwr
+= group
->__cpu_power
;
3832 sds
->this_load
= sgs
.avg_load
;
3834 sds
->this_nr_running
= sgs
.sum_nr_running
;
3835 sds
->this_load_per_task
= sgs
.sum_weighted_load
;
3836 } else if (sgs
.avg_load
> sds
->max_load
&&
3837 (sgs
.sum_nr_running
> sgs
.group_capacity
||
3839 sds
->max_load
= sgs
.avg_load
;
3840 sds
->busiest
= group
;
3841 sds
->busiest_nr_running
= sgs
.sum_nr_running
;
3842 sds
->busiest_load_per_task
= sgs
.sum_weighted_load
;
3843 sds
->group_imb
= sgs
.group_imb
;
3846 update_sd_power_savings_stats(group
, sds
, local_group
, &sgs
);
3847 group
= group
->next
;
3848 } while (group
!= sd
->groups
);
3853 * fix_small_imbalance - Calculate the minor imbalance that exists
3854 * amongst the groups of a sched_domain, during
3856 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3857 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3858 * @imbalance: Variable to store the imbalance.
3860 static inline void fix_small_imbalance(struct sd_lb_stats
*sds
,
3861 int this_cpu
, unsigned long *imbalance
)
3863 unsigned long tmp
, pwr_now
= 0, pwr_move
= 0;
3864 unsigned int imbn
= 2;
3866 if (sds
->this_nr_running
) {
3867 sds
->this_load_per_task
/= sds
->this_nr_running
;
3868 if (sds
->busiest_load_per_task
>
3869 sds
->this_load_per_task
)
3872 sds
->this_load_per_task
=
3873 cpu_avg_load_per_task(this_cpu
);
3875 if (sds
->max_load
- sds
->this_load
+ sds
->busiest_load_per_task
>=
3876 sds
->busiest_load_per_task
* imbn
) {
3877 *imbalance
= sds
->busiest_load_per_task
;
3882 * OK, we don't have enough imbalance to justify moving tasks,
3883 * however we may be able to increase total CPU power used by
3887 pwr_now
+= sds
->busiest
->__cpu_power
*
3888 min(sds
->busiest_load_per_task
, sds
->max_load
);
3889 pwr_now
+= sds
->this->__cpu_power
*
3890 min(sds
->this_load_per_task
, sds
->this_load
);
3891 pwr_now
/= SCHED_LOAD_SCALE
;
3893 /* Amount of load we'd subtract */
3894 tmp
= sg_div_cpu_power(sds
->busiest
,
3895 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
);
3896 if (sds
->max_load
> tmp
)
3897 pwr_move
+= sds
->busiest
->__cpu_power
*
3898 min(sds
->busiest_load_per_task
, sds
->max_load
- tmp
);
3900 /* Amount of load we'd add */
3901 if (sds
->max_load
* sds
->busiest
->__cpu_power
<
3902 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
)
3903 tmp
= sg_div_cpu_power(sds
->this,
3904 sds
->max_load
* sds
->busiest
->__cpu_power
);
3906 tmp
= sg_div_cpu_power(sds
->this,
3907 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
);
3908 pwr_move
+= sds
->this->__cpu_power
*
3909 min(sds
->this_load_per_task
, sds
->this_load
+ tmp
);
3910 pwr_move
/= SCHED_LOAD_SCALE
;
3912 /* Move if we gain throughput */
3913 if (pwr_move
> pwr_now
)
3914 *imbalance
= sds
->busiest_load_per_task
;
3918 * calculate_imbalance - Calculate the amount of imbalance present within the
3919 * groups of a given sched_domain during load balance.
3920 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3921 * @this_cpu: Cpu for which currently load balance is being performed.
3922 * @imbalance: The variable to store the imbalance.
3924 static inline void calculate_imbalance(struct sd_lb_stats
*sds
, int this_cpu
,
3925 unsigned long *imbalance
)
3927 unsigned long max_pull
;
3929 * In the presence of smp nice balancing, certain scenarios can have
3930 * max load less than avg load(as we skip the groups at or below
3931 * its cpu_power, while calculating max_load..)
3933 if (sds
->max_load
< sds
->avg_load
) {
3935 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3938 /* Don't want to pull so many tasks that a group would go idle */
3939 max_pull
= min(sds
->max_load
- sds
->avg_load
,
3940 sds
->max_load
- sds
->busiest_load_per_task
);
3942 /* How much load to actually move to equalise the imbalance */
3943 *imbalance
= min(max_pull
* sds
->busiest
->__cpu_power
,
3944 (sds
->avg_load
- sds
->this_load
) * sds
->this->__cpu_power
)
3948 * if *imbalance is less than the average load per runnable task
3949 * there is no gaurantee that any tasks will be moved so we'll have
3950 * a think about bumping its value to force at least one task to be
3953 if (*imbalance
< sds
->busiest_load_per_task
)
3954 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3957 /******* find_busiest_group() helpers end here *********************/
3960 * find_busiest_group - Returns the busiest group within the sched_domain
3961 * if there is an imbalance. If there isn't an imbalance, and
3962 * the user has opted for power-savings, it returns a group whose
3963 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3964 * such a group exists.
3966 * Also calculates the amount of weighted load which should be moved
3967 * to restore balance.
3969 * @sd: The sched_domain whose busiest group is to be returned.
3970 * @this_cpu: The cpu for which load balancing is currently being performed.
3971 * @imbalance: Variable which stores amount of weighted load which should
3972 * be moved to restore balance/put a group to idle.
3973 * @idle: The idle status of this_cpu.
3974 * @sd_idle: The idleness of sd
3975 * @cpus: The set of CPUs under consideration for load-balancing.
3976 * @balance: Pointer to a variable indicating if this_cpu
3977 * is the appropriate cpu to perform load balancing at this_level.
3979 * Returns: - the busiest group if imbalance exists.
3980 * - If no imbalance and user has opted for power-savings balance,
3981 * return the least loaded group whose CPUs can be
3982 * put to idle by rebalancing its tasks onto our group.
3984 static struct sched_group
*
3985 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3986 unsigned long *imbalance
, enum cpu_idle_type idle
,
3987 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
3989 struct sd_lb_stats sds
;
3991 memset(&sds
, 0, sizeof(sds
));
3994 * Compute the various statistics relavent for load balancing at
3997 update_sd_lb_stats(sd
, this_cpu
, idle
, sd_idle
, cpus
,
4000 /* Cases where imbalance does not exist from POV of this_cpu */
4001 /* 1) this_cpu is not the appropriate cpu to perform load balancing
4003 * 2) There is no busy sibling group to pull from.
4004 * 3) This group is the busiest group.
4005 * 4) This group is more busy than the avg busieness at this
4007 * 5) The imbalance is within the specified limit.
4008 * 6) Any rebalance would lead to ping-pong
4010 if (balance
&& !(*balance
))
4013 if (!sds
.busiest
|| sds
.busiest_nr_running
== 0)
4016 if (sds
.this_load
>= sds
.max_load
)
4019 sds
.avg_load
= (SCHED_LOAD_SCALE
* sds
.total_load
) / sds
.total_pwr
;
4021 if (sds
.this_load
>= sds
.avg_load
)
4024 if (100 * sds
.max_load
<= sd
->imbalance_pct
* sds
.this_load
)
4027 sds
.busiest_load_per_task
/= sds
.busiest_nr_running
;
4029 sds
.busiest_load_per_task
=
4030 min(sds
.busiest_load_per_task
, sds
.avg_load
);
4033 * We're trying to get all the cpus to the average_load, so we don't
4034 * want to push ourselves above the average load, nor do we wish to
4035 * reduce the max loaded cpu below the average load, as either of these
4036 * actions would just result in more rebalancing later, and ping-pong
4037 * tasks around. Thus we look for the minimum possible imbalance.
4038 * Negative imbalances (*we* are more loaded than anyone else) will
4039 * be counted as no imbalance for these purposes -- we can't fix that
4040 * by pulling tasks to us. Be careful of negative numbers as they'll
4041 * appear as very large values with unsigned longs.
4043 if (sds
.max_load
<= sds
.busiest_load_per_task
)
4046 /* Looks like there is an imbalance. Compute it */
4047 calculate_imbalance(&sds
, this_cpu
, imbalance
);
4052 * There is no obvious imbalance. But check if we can do some balancing
4055 if (check_power_save_busiest_group(&sds
, this_cpu
, imbalance
))
4063 * find_busiest_queue - find the busiest runqueue among the cpus in group.
4066 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
4067 unsigned long imbalance
, const struct cpumask
*cpus
)
4069 struct rq
*busiest
= NULL
, *rq
;
4070 unsigned long max_load
= 0;
4073 for_each_cpu(i
, sched_group_cpus(group
)) {
4076 if (!cpumask_test_cpu(i
, cpus
))
4080 wl
= weighted_cpuload(i
);
4082 if (rq
->nr_running
== 1 && wl
> imbalance
)
4085 if (wl
> max_load
) {
4095 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
4096 * so long as it is large enough.
4098 #define MAX_PINNED_INTERVAL 512
4100 /* Working cpumask for load_balance and load_balance_newidle. */
4101 static DEFINE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
4104 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4105 * tasks if there is an imbalance.
4107 static int load_balance(int this_cpu
, struct rq
*this_rq
,
4108 struct sched_domain
*sd
, enum cpu_idle_type idle
,
4111 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
4112 struct sched_group
*group
;
4113 unsigned long imbalance
;
4115 unsigned long flags
;
4116 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4118 cpumask_setall(cpus
);
4121 * When power savings policy is enabled for the parent domain, idle
4122 * sibling can pick up load irrespective of busy siblings. In this case,
4123 * let the state of idle sibling percolate up as CPU_IDLE, instead of
4124 * portraying it as CPU_NOT_IDLE.
4126 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4127 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4130 schedstat_inc(sd
, lb_count
[idle
]);
4134 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
4141 schedstat_inc(sd
, lb_nobusyg
[idle
]);
4145 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
4147 schedstat_inc(sd
, lb_nobusyq
[idle
]);
4151 BUG_ON(busiest
== this_rq
);
4153 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
4156 if (busiest
->nr_running
> 1) {
4158 * Attempt to move tasks. If find_busiest_group has found
4159 * an imbalance but busiest->nr_running <= 1, the group is
4160 * still unbalanced. ld_moved simply stays zero, so it is
4161 * correctly treated as an imbalance.
4163 local_irq_save(flags
);
4164 double_rq_lock(this_rq
, busiest
);
4165 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4166 imbalance
, sd
, idle
, &all_pinned
);
4167 double_rq_unlock(this_rq
, busiest
);
4168 local_irq_restore(flags
);
4171 * some other cpu did the load balance for us.
4173 if (ld_moved
&& this_cpu
!= smp_processor_id())
4174 resched_cpu(this_cpu
);
4176 /* All tasks on this runqueue were pinned by CPU affinity */
4177 if (unlikely(all_pinned
)) {
4178 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4179 if (!cpumask_empty(cpus
))
4186 schedstat_inc(sd
, lb_failed
[idle
]);
4187 sd
->nr_balance_failed
++;
4189 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
4191 spin_lock_irqsave(&busiest
->lock
, flags
);
4193 /* don't kick the migration_thread, if the curr
4194 * task on busiest cpu can't be moved to this_cpu
4196 if (!cpumask_test_cpu(this_cpu
,
4197 &busiest
->curr
->cpus_allowed
)) {
4198 spin_unlock_irqrestore(&busiest
->lock
, flags
);
4200 goto out_one_pinned
;
4203 if (!busiest
->active_balance
) {
4204 busiest
->active_balance
= 1;
4205 busiest
->push_cpu
= this_cpu
;
4208 spin_unlock_irqrestore(&busiest
->lock
, flags
);
4210 wake_up_process(busiest
->migration_thread
);
4213 * We've kicked active balancing, reset the failure
4216 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
4219 sd
->nr_balance_failed
= 0;
4221 if (likely(!active_balance
)) {
4222 /* We were unbalanced, so reset the balancing interval */
4223 sd
->balance_interval
= sd
->min_interval
;
4226 * If we've begun active balancing, start to back off. This
4227 * case may not be covered by the all_pinned logic if there
4228 * is only 1 task on the busy runqueue (because we don't call
4231 if (sd
->balance_interval
< sd
->max_interval
)
4232 sd
->balance_interval
*= 2;
4235 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4236 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4242 schedstat_inc(sd
, lb_balanced
[idle
]);
4244 sd
->nr_balance_failed
= 0;
4247 /* tune up the balancing interval */
4248 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
4249 (sd
->balance_interval
< sd
->max_interval
))
4250 sd
->balance_interval
*= 2;
4252 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4253 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4264 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4265 * tasks if there is an imbalance.
4267 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4268 * this_rq is locked.
4271 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
)
4273 struct sched_group
*group
;
4274 struct rq
*busiest
= NULL
;
4275 unsigned long imbalance
;
4279 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4281 cpumask_setall(cpus
);
4284 * When power savings policy is enabled for the parent domain, idle
4285 * sibling can pick up load irrespective of busy siblings. In this case,
4286 * let the state of idle sibling percolate up as IDLE, instead of
4287 * portraying it as CPU_NOT_IDLE.
4289 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
4290 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4293 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
4295 update_shares_locked(this_rq
, sd
);
4296 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
4297 &sd_idle
, cpus
, NULL
);
4299 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
4303 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
4305 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
4309 BUG_ON(busiest
== this_rq
);
4311 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
4314 if (busiest
->nr_running
> 1) {
4315 /* Attempt to move tasks */
4316 double_lock_balance(this_rq
, busiest
);
4317 /* this_rq->clock is already updated */
4318 update_rq_clock(busiest
);
4319 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4320 imbalance
, sd
, CPU_NEWLY_IDLE
,
4322 double_unlock_balance(this_rq
, busiest
);
4324 if (unlikely(all_pinned
)) {
4325 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4326 if (!cpumask_empty(cpus
))
4332 int active_balance
= 0;
4334 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
4335 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4336 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4339 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
4342 if (sd
->nr_balance_failed
++ < 2)
4346 * The only task running in a non-idle cpu can be moved to this
4347 * cpu in an attempt to completely freeup the other CPU
4348 * package. The same method used to move task in load_balance()
4349 * have been extended for load_balance_newidle() to speedup
4350 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4352 * The package power saving logic comes from
4353 * find_busiest_group(). If there are no imbalance, then
4354 * f_b_g() will return NULL. However when sched_mc={1,2} then
4355 * f_b_g() will select a group from which a running task may be
4356 * pulled to this cpu in order to make the other package idle.
4357 * If there is no opportunity to make a package idle and if
4358 * there are no imbalance, then f_b_g() will return NULL and no
4359 * action will be taken in load_balance_newidle().
4361 * Under normal task pull operation due to imbalance, there
4362 * will be more than one task in the source run queue and
4363 * move_tasks() will succeed. ld_moved will be true and this
4364 * active balance code will not be triggered.
4367 /* Lock busiest in correct order while this_rq is held */
4368 double_lock_balance(this_rq
, busiest
);
4371 * don't kick the migration_thread, if the curr
4372 * task on busiest cpu can't be moved to this_cpu
4374 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
4375 double_unlock_balance(this_rq
, busiest
);
4380 if (!busiest
->active_balance
) {
4381 busiest
->active_balance
= 1;
4382 busiest
->push_cpu
= this_cpu
;
4386 double_unlock_balance(this_rq
, busiest
);
4388 * Should not call ttwu while holding a rq->lock
4390 spin_unlock(&this_rq
->lock
);
4392 wake_up_process(busiest
->migration_thread
);
4393 spin_lock(&this_rq
->lock
);
4396 sd
->nr_balance_failed
= 0;
4398 update_shares_locked(this_rq
, sd
);
4402 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
4403 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4404 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4406 sd
->nr_balance_failed
= 0;
4412 * idle_balance is called by schedule() if this_cpu is about to become
4413 * idle. Attempts to pull tasks from other CPUs.
4415 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
4417 struct sched_domain
*sd
;
4418 int pulled_task
= 0;
4419 unsigned long next_balance
= jiffies
+ HZ
;
4421 for_each_domain(this_cpu
, sd
) {
4422 unsigned long interval
;
4424 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4427 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
4428 /* If we've pulled tasks over stop searching: */
4429 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
4432 interval
= msecs_to_jiffies(sd
->balance_interval
);
4433 if (time_after(next_balance
, sd
->last_balance
+ interval
))
4434 next_balance
= sd
->last_balance
+ interval
;
4438 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
4440 * We are going idle. next_balance may be set based on
4441 * a busy processor. So reset next_balance.
4443 this_rq
->next_balance
= next_balance
;
4448 * active_load_balance is run by migration threads. It pushes running tasks
4449 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4450 * running on each physical CPU where possible, and avoids physical /
4451 * logical imbalances.
4453 * Called with busiest_rq locked.
4455 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
4457 int target_cpu
= busiest_rq
->push_cpu
;
4458 struct sched_domain
*sd
;
4459 struct rq
*target_rq
;
4461 /* Is there any task to move? */
4462 if (busiest_rq
->nr_running
<= 1)
4465 target_rq
= cpu_rq(target_cpu
);
4468 * This condition is "impossible", if it occurs
4469 * we need to fix it. Originally reported by
4470 * Bjorn Helgaas on a 128-cpu setup.
4472 BUG_ON(busiest_rq
== target_rq
);
4474 /* move a task from busiest_rq to target_rq */
4475 double_lock_balance(busiest_rq
, target_rq
);
4476 update_rq_clock(busiest_rq
);
4477 update_rq_clock(target_rq
);
4479 /* Search for an sd spanning us and the target CPU. */
4480 for_each_domain(target_cpu
, sd
) {
4481 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
4482 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
4487 schedstat_inc(sd
, alb_count
);
4489 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
4491 schedstat_inc(sd
, alb_pushed
);
4493 schedstat_inc(sd
, alb_failed
);
4495 double_unlock_balance(busiest_rq
, target_rq
);
4500 atomic_t load_balancer
;
4501 cpumask_var_t cpu_mask
;
4502 cpumask_var_t ilb_grp_nohz_mask
;
4503 } nohz ____cacheline_aligned
= {
4504 .load_balancer
= ATOMIC_INIT(-1),
4507 int get_nohz_load_balancer(void)
4509 return atomic_read(&nohz
.load_balancer
);
4512 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
4514 * lowest_flag_domain - Return lowest sched_domain containing flag.
4515 * @cpu: The cpu whose lowest level of sched domain is to
4517 * @flag: The flag to check for the lowest sched_domain
4518 * for the given cpu.
4520 * Returns the lowest sched_domain of a cpu which contains the given flag.
4522 static inline struct sched_domain
*lowest_flag_domain(int cpu
, int flag
)
4524 struct sched_domain
*sd
;
4526 for_each_domain(cpu
, sd
)
4527 if (sd
&& (sd
->flags
& flag
))
4534 * for_each_flag_domain - Iterates over sched_domains containing the flag.
4535 * @cpu: The cpu whose domains we're iterating over.
4536 * @sd: variable holding the value of the power_savings_sd
4538 * @flag: The flag to filter the sched_domains to be iterated.
4540 * Iterates over all the scheduler domains for a given cpu that has the 'flag'
4541 * set, starting from the lowest sched_domain to the highest.
4543 #define for_each_flag_domain(cpu, sd, flag) \
4544 for (sd = lowest_flag_domain(cpu, flag); \
4545 (sd && (sd->flags & flag)); sd = sd->parent)
4548 * is_semi_idle_group - Checks if the given sched_group is semi-idle.
4549 * @ilb_group: group to be checked for semi-idleness
4551 * Returns: 1 if the group is semi-idle. 0 otherwise.
4553 * We define a sched_group to be semi idle if it has atleast one idle-CPU
4554 * and atleast one non-idle CPU. This helper function checks if the given
4555 * sched_group is semi-idle or not.
4557 static inline int is_semi_idle_group(struct sched_group
*ilb_group
)
4559 cpumask_and(nohz
.ilb_grp_nohz_mask
, nohz
.cpu_mask
,
4560 sched_group_cpus(ilb_group
));
4563 * A sched_group is semi-idle when it has atleast one busy cpu
4564 * and atleast one idle cpu.
4566 if (cpumask_empty(nohz
.ilb_grp_nohz_mask
))
4569 if (cpumask_equal(nohz
.ilb_grp_nohz_mask
, sched_group_cpus(ilb_group
)))
4575 * find_new_ilb - Finds the optimum idle load balancer for nomination.
4576 * @cpu: The cpu which is nominating a new idle_load_balancer.
4578 * Returns: Returns the id of the idle load balancer if it exists,
4579 * Else, returns >= nr_cpu_ids.
4581 * This algorithm picks the idle load balancer such that it belongs to a
4582 * semi-idle powersavings sched_domain. The idea is to try and avoid
4583 * completely idle packages/cores just for the purpose of idle load balancing
4584 * when there are other idle cpu's which are better suited for that job.
4586 static int find_new_ilb(int cpu
)
4588 struct sched_domain
*sd
;
4589 struct sched_group
*ilb_group
;
4592 * Have idle load balancer selection from semi-idle packages only
4593 * when power-aware load balancing is enabled
4595 if (!(sched_smt_power_savings
|| sched_mc_power_savings
))
4599 * Optimize for the case when we have no idle CPUs or only one
4600 * idle CPU. Don't walk the sched_domain hierarchy in such cases
4602 if (cpumask_weight(nohz
.cpu_mask
) < 2)
4605 for_each_flag_domain(cpu
, sd
, SD_POWERSAVINGS_BALANCE
) {
4606 ilb_group
= sd
->groups
;
4609 if (is_semi_idle_group(ilb_group
))
4610 return cpumask_first(nohz
.ilb_grp_nohz_mask
);
4612 ilb_group
= ilb_group
->next
;
4614 } while (ilb_group
!= sd
->groups
);
4618 return cpumask_first(nohz
.cpu_mask
);
4620 #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
4621 static inline int find_new_ilb(int call_cpu
)
4623 return cpumask_first(nohz
.cpu_mask
);
4628 * This routine will try to nominate the ilb (idle load balancing)
4629 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4630 * load balancing on behalf of all those cpus. If all the cpus in the system
4631 * go into this tickless mode, then there will be no ilb owner (as there is
4632 * no need for one) and all the cpus will sleep till the next wakeup event
4635 * For the ilb owner, tick is not stopped. And this tick will be used
4636 * for idle load balancing. ilb owner will still be part of
4639 * While stopping the tick, this cpu will become the ilb owner if there
4640 * is no other owner. And will be the owner till that cpu becomes busy
4641 * or if all cpus in the system stop their ticks at which point
4642 * there is no need for ilb owner.
4644 * When the ilb owner becomes busy, it nominates another owner, during the
4645 * next busy scheduler_tick()
4647 int select_nohz_load_balancer(int stop_tick
)
4649 int cpu
= smp_processor_id();
4652 cpu_rq(cpu
)->in_nohz_recently
= 1;
4654 if (!cpu_active(cpu
)) {
4655 if (atomic_read(&nohz
.load_balancer
) != cpu
)
4659 * If we are going offline and still the leader,
4662 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4668 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
4670 /* time for ilb owner also to sleep */
4671 if (cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4672 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4673 atomic_set(&nohz
.load_balancer
, -1);
4677 if (atomic_read(&nohz
.load_balancer
) == -1) {
4678 /* make me the ilb owner */
4679 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4681 } else if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4684 if (!(sched_smt_power_savings
||
4685 sched_mc_power_savings
))
4688 * Check to see if there is a more power-efficient
4691 new_ilb
= find_new_ilb(cpu
);
4692 if (new_ilb
< nr_cpu_ids
&& new_ilb
!= cpu
) {
4693 atomic_set(&nohz
.load_balancer
, -1);
4694 resched_cpu(new_ilb
);
4700 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4703 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4705 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4706 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4713 static DEFINE_SPINLOCK(balancing
);
4716 * It checks each scheduling domain to see if it is due to be balanced,
4717 * and initiates a balancing operation if so.
4719 * Balancing parameters are set up in arch_init_sched_domains.
4721 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4724 struct rq
*rq
= cpu_rq(cpu
);
4725 unsigned long interval
;
4726 struct sched_domain
*sd
;
4727 /* Earliest time when we have to do rebalance again */
4728 unsigned long next_balance
= jiffies
+ 60*HZ
;
4729 int update_next_balance
= 0;
4732 for_each_domain(cpu
, sd
) {
4733 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4736 interval
= sd
->balance_interval
;
4737 if (idle
!= CPU_IDLE
)
4738 interval
*= sd
->busy_factor
;
4740 /* scale ms to jiffies */
4741 interval
= msecs_to_jiffies(interval
);
4742 if (unlikely(!interval
))
4744 if (interval
> HZ
*NR_CPUS
/10)
4745 interval
= HZ
*NR_CPUS
/10;
4747 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4749 if (need_serialize
) {
4750 if (!spin_trylock(&balancing
))
4754 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4755 if (load_balance(cpu
, rq
, sd
, idle
, &balance
)) {
4757 * We've pulled tasks over so either we're no
4758 * longer idle, or one of our SMT siblings is
4761 idle
= CPU_NOT_IDLE
;
4763 sd
->last_balance
= jiffies
;
4766 spin_unlock(&balancing
);
4768 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4769 next_balance
= sd
->last_balance
+ interval
;
4770 update_next_balance
= 1;
4774 * Stop the load balance at this level. There is another
4775 * CPU in our sched group which is doing load balancing more
4783 * next_balance will be updated only when there is a need.
4784 * When the cpu is attached to null domain for ex, it will not be
4787 if (likely(update_next_balance
))
4788 rq
->next_balance
= next_balance
;
4792 * run_rebalance_domains is triggered when needed from the scheduler tick.
4793 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4794 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4796 static void run_rebalance_domains(struct softirq_action
*h
)
4798 int this_cpu
= smp_processor_id();
4799 struct rq
*this_rq
= cpu_rq(this_cpu
);
4800 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4801 CPU_IDLE
: CPU_NOT_IDLE
;
4803 rebalance_domains(this_cpu
, idle
);
4807 * If this cpu is the owner for idle load balancing, then do the
4808 * balancing on behalf of the other idle cpus whose ticks are
4811 if (this_rq
->idle_at_tick
&&
4812 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4816 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4817 if (balance_cpu
== this_cpu
)
4821 * If this cpu gets work to do, stop the load balancing
4822 * work being done for other cpus. Next load
4823 * balancing owner will pick it up.
4828 rebalance_domains(balance_cpu
, CPU_IDLE
);
4830 rq
= cpu_rq(balance_cpu
);
4831 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4832 this_rq
->next_balance
= rq
->next_balance
;
4838 static inline int on_null_domain(int cpu
)
4840 return !rcu_dereference(cpu_rq(cpu
)->sd
);
4844 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4846 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4847 * idle load balancing owner or decide to stop the periodic load balancing,
4848 * if the whole system is idle.
4850 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4854 * If we were in the nohz mode recently and busy at the current
4855 * scheduler tick, then check if we need to nominate new idle
4858 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4859 rq
->in_nohz_recently
= 0;
4861 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4862 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4863 atomic_set(&nohz
.load_balancer
, -1);
4866 if (atomic_read(&nohz
.load_balancer
) == -1) {
4867 int ilb
= find_new_ilb(cpu
);
4869 if (ilb
< nr_cpu_ids
)
4875 * If this cpu is idle and doing idle load balancing for all the
4876 * cpus with ticks stopped, is it time for that to stop?
4878 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4879 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4885 * If this cpu is idle and the idle load balancing is done by
4886 * someone else, then no need raise the SCHED_SOFTIRQ
4888 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4889 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4892 /* Don't need to rebalance while attached to NULL domain */
4893 if (time_after_eq(jiffies
, rq
->next_balance
) &&
4894 likely(!on_null_domain(cpu
)))
4895 raise_softirq(SCHED_SOFTIRQ
);
4898 #else /* CONFIG_SMP */
4901 * on UP we do not need to balance between CPUs:
4903 static inline void idle_balance(int cpu
, struct rq
*rq
)
4909 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4911 EXPORT_PER_CPU_SYMBOL(kstat
);
4914 * Return any ns on the sched_clock that have not yet been accounted in
4915 * @p in case that task is currently running.
4917 * Called with task_rq_lock() held on @rq.
4919 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
4923 if (task_current(rq
, p
)) {
4924 update_rq_clock(rq
);
4925 ns
= rq
->clock
- p
->se
.exec_start
;
4933 unsigned long long task_delta_exec(struct task_struct
*p
)
4935 unsigned long flags
;
4939 rq
= task_rq_lock(p
, &flags
);
4940 ns
= do_task_delta_exec(p
, rq
);
4941 task_rq_unlock(rq
, &flags
);
4947 * Return accounted runtime for the task.
4948 * In case the task is currently running, return the runtime plus current's
4949 * pending runtime that have not been accounted yet.
4951 unsigned long long task_sched_runtime(struct task_struct
*p
)
4953 unsigned long flags
;
4957 rq
= task_rq_lock(p
, &flags
);
4958 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4959 task_rq_unlock(rq
, &flags
);
4965 * Return sum_exec_runtime for the thread group.
4966 * In case the task is currently running, return the sum plus current's
4967 * pending runtime that have not been accounted yet.
4969 * Note that the thread group might have other running tasks as well,
4970 * so the return value not includes other pending runtime that other
4971 * running tasks might have.
4973 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
4975 struct task_cputime totals
;
4976 unsigned long flags
;
4980 rq
= task_rq_lock(p
, &flags
);
4981 thread_group_cputime(p
, &totals
);
4982 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4983 task_rq_unlock(rq
, &flags
);
4989 * Account user cpu time to a process.
4990 * @p: the process that the cpu time gets accounted to
4991 * @cputime: the cpu time spent in user space since the last update
4992 * @cputime_scaled: cputime scaled by cpu frequency
4994 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
4995 cputime_t cputime_scaled
)
4997 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5000 /* Add user time to process. */
5001 p
->utime
= cputime_add(p
->utime
, cputime
);
5002 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
5003 account_group_user_time(p
, cputime
);
5005 /* Add user time to cpustat. */
5006 tmp
= cputime_to_cputime64(cputime
);
5007 if (TASK_NICE(p
) > 0)
5008 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
5010 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
5012 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
5013 /* Account for user time used */
5014 acct_update_integrals(p
);
5018 * Account guest cpu time to a process.
5019 * @p: the process that the cpu time gets accounted to
5020 * @cputime: the cpu time spent in virtual machine since the last update
5021 * @cputime_scaled: cputime scaled by cpu frequency
5023 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
5024 cputime_t cputime_scaled
)
5027 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5029 tmp
= cputime_to_cputime64(cputime
);
5031 /* Add guest time to process. */
5032 p
->utime
= cputime_add(p
->utime
, cputime
);
5033 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
5034 account_group_user_time(p
, cputime
);
5035 p
->gtime
= cputime_add(p
->gtime
, cputime
);
5037 /* Add guest time to cpustat. */
5038 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
5039 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
5043 * Account system cpu time to a process.
5044 * @p: the process that the cpu time gets accounted to
5045 * @hardirq_offset: the offset to subtract from hardirq_count()
5046 * @cputime: the cpu time spent in kernel space since the last update
5047 * @cputime_scaled: cputime scaled by cpu frequency
5049 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
5050 cputime_t cputime
, cputime_t cputime_scaled
)
5052 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5055 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
5056 account_guest_time(p
, cputime
, cputime_scaled
);
5060 /* Add system time to process. */
5061 p
->stime
= cputime_add(p
->stime
, cputime
);
5062 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
5063 account_group_system_time(p
, cputime
);
5065 /* Add system time to cpustat. */
5066 tmp
= cputime_to_cputime64(cputime
);
5067 if (hardirq_count() - hardirq_offset
)
5068 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
5069 else if (softirq_count())
5070 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
5072 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
5074 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
5076 /* Account for system time used */
5077 acct_update_integrals(p
);
5081 * Account for involuntary wait time.
5082 * @steal: the cpu time spent in involuntary wait
5084 void account_steal_time(cputime_t cputime
)
5086 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5087 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5089 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
5093 * Account for idle time.
5094 * @cputime: the cpu time spent in idle wait
5096 void account_idle_time(cputime_t cputime
)
5098 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5099 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5100 struct rq
*rq
= this_rq();
5102 if (atomic_read(&rq
->nr_iowait
) > 0)
5103 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
5105 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
5108 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
5111 * Account a single tick of cpu time.
5112 * @p: the process that the cpu time gets accounted to
5113 * @user_tick: indicates if the tick is a user or a system tick
5115 void account_process_tick(struct task_struct
*p
, int user_tick
)
5117 cputime_t one_jiffy
= jiffies_to_cputime(1);
5118 cputime_t one_jiffy_scaled
= cputime_to_scaled(one_jiffy
);
5119 struct rq
*rq
= this_rq();
5122 account_user_time(p
, one_jiffy
, one_jiffy_scaled
);
5123 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
5124 account_system_time(p
, HARDIRQ_OFFSET
, one_jiffy
,
5127 account_idle_time(one_jiffy
);
5131 * Account multiple ticks of steal time.
5132 * @p: the process from which the cpu time has been stolen
5133 * @ticks: number of stolen ticks
5135 void account_steal_ticks(unsigned long ticks
)
5137 account_steal_time(jiffies_to_cputime(ticks
));
5141 * Account multiple ticks of idle time.
5142 * @ticks: number of stolen ticks
5144 void account_idle_ticks(unsigned long ticks
)
5146 account_idle_time(jiffies_to_cputime(ticks
));
5152 * Use precise platform statistics if available:
5154 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
5155 cputime_t
task_utime(struct task_struct
*p
)
5160 cputime_t
task_stime(struct task_struct
*p
)
5165 cputime_t
task_utime(struct task_struct
*p
)
5167 clock_t utime
= cputime_to_clock_t(p
->utime
),
5168 total
= utime
+ cputime_to_clock_t(p
->stime
);
5172 * Use CFS's precise accounting:
5174 temp
= (u64
)nsec_to_clock_t(p
->se
.sum_exec_runtime
);
5178 do_div(temp
, total
);
5180 utime
= (clock_t)temp
;
5182 p
->prev_utime
= max(p
->prev_utime
, clock_t_to_cputime(utime
));
5183 return p
->prev_utime
;
5186 cputime_t
task_stime(struct task_struct
*p
)
5191 * Use CFS's precise accounting. (we subtract utime from
5192 * the total, to make sure the total observed by userspace
5193 * grows monotonically - apps rely on that):
5195 stime
= nsec_to_clock_t(p
->se
.sum_exec_runtime
) -
5196 cputime_to_clock_t(task_utime(p
));
5199 p
->prev_stime
= max(p
->prev_stime
, clock_t_to_cputime(stime
));
5201 return p
->prev_stime
;
5205 inline cputime_t
task_gtime(struct task_struct
*p
)
5211 * This function gets called by the timer code, with HZ frequency.
5212 * We call it with interrupts disabled.
5214 * It also gets called by the fork code, when changing the parent's
5217 void scheduler_tick(void)
5219 int cpu
= smp_processor_id();
5220 struct rq
*rq
= cpu_rq(cpu
);
5221 struct task_struct
*curr
= rq
->curr
;
5225 spin_lock(&rq
->lock
);
5226 update_rq_clock(rq
);
5227 update_cpu_load(rq
);
5228 curr
->sched_class
->task_tick(rq
, curr
, 0);
5229 spin_unlock(&rq
->lock
);
5231 perf_counter_task_tick(curr
, cpu
);
5234 rq
->idle_at_tick
= idle_cpu(cpu
);
5235 trigger_load_balance(rq
, cpu
);
5239 notrace
unsigned long get_parent_ip(unsigned long addr
)
5241 if (in_lock_functions(addr
)) {
5242 addr
= CALLER_ADDR2
;
5243 if (in_lock_functions(addr
))
5244 addr
= CALLER_ADDR3
;
5249 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
5250 defined(CONFIG_PREEMPT_TRACER))
5252 void __kprobes
add_preempt_count(int val
)
5254 #ifdef CONFIG_DEBUG_PREEMPT
5258 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
5261 preempt_count() += val
;
5262 #ifdef CONFIG_DEBUG_PREEMPT
5264 * Spinlock count overflowing soon?
5266 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
5269 if (preempt_count() == val
)
5270 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5272 EXPORT_SYMBOL(add_preempt_count
);
5274 void __kprobes
sub_preempt_count(int val
)
5276 #ifdef CONFIG_DEBUG_PREEMPT
5280 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
5283 * Is the spinlock portion underflowing?
5285 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
5286 !(preempt_count() & PREEMPT_MASK
)))
5290 if (preempt_count() == val
)
5291 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5292 preempt_count() -= val
;
5294 EXPORT_SYMBOL(sub_preempt_count
);
5299 * Print scheduling while atomic bug:
5301 static noinline
void __schedule_bug(struct task_struct
*prev
)
5303 struct pt_regs
*regs
= get_irq_regs();
5305 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
5306 prev
->comm
, prev
->pid
, preempt_count());
5308 debug_show_held_locks(prev
);
5310 if (irqs_disabled())
5311 print_irqtrace_events(prev
);
5320 * Various schedule()-time debugging checks and statistics:
5322 static inline void schedule_debug(struct task_struct
*prev
)
5325 * Test if we are atomic. Since do_exit() needs to call into
5326 * schedule() atomically, we ignore that path for now.
5327 * Otherwise, whine if we are scheduling when we should not be.
5329 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
5330 __schedule_bug(prev
);
5332 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
5334 schedstat_inc(this_rq(), sched_count
);
5335 #ifdef CONFIG_SCHEDSTATS
5336 if (unlikely(prev
->lock_depth
>= 0)) {
5337 schedstat_inc(this_rq(), bkl_count
);
5338 schedstat_inc(prev
, sched_info
.bkl_count
);
5343 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
5345 if (prev
->state
== TASK_RUNNING
) {
5346 u64 runtime
= prev
->se
.sum_exec_runtime
;
5348 runtime
-= prev
->se
.prev_sum_exec_runtime
;
5349 runtime
= min_t(u64
, runtime
, 2*sysctl_sched_migration_cost
);
5352 * In order to avoid avg_overlap growing stale when we are
5353 * indeed overlapping and hence not getting put to sleep, grow
5354 * the avg_overlap on preemption.
5356 * We use the average preemption runtime because that
5357 * correlates to the amount of cache footprint a task can
5360 update_avg(&prev
->se
.avg_overlap
, runtime
);
5362 prev
->sched_class
->put_prev_task(rq
, prev
);
5366 * Pick up the highest-prio task:
5368 static inline struct task_struct
*
5369 pick_next_task(struct rq
*rq
)
5371 const struct sched_class
*class;
5372 struct task_struct
*p
;
5375 * Optimization: we know that if all tasks are in
5376 * the fair class we can call that function directly:
5378 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
5379 p
= fair_sched_class
.pick_next_task(rq
);
5384 class = sched_class_highest
;
5386 p
= class->pick_next_task(rq
);
5390 * Will never be NULL as the idle class always
5391 * returns a non-NULL p:
5393 class = class->next
;
5398 * schedule() is the main scheduler function.
5400 asmlinkage
void __sched
schedule(void)
5402 struct task_struct
*prev
, *next
;
5403 unsigned long *switch_count
;
5409 cpu
= smp_processor_id();
5413 switch_count
= &prev
->nivcsw
;
5415 release_kernel_lock(prev
);
5416 need_resched_nonpreemptible
:
5418 schedule_debug(prev
);
5420 if (sched_feat(HRTICK
))
5423 spin_lock_irq(&rq
->lock
);
5424 update_rq_clock(rq
);
5425 clear_tsk_need_resched(prev
);
5427 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
5428 if (unlikely(signal_pending_state(prev
->state
, prev
)))
5429 prev
->state
= TASK_RUNNING
;
5431 deactivate_task(rq
, prev
, 1);
5432 switch_count
= &prev
->nvcsw
;
5435 pre_schedule(rq
, prev
);
5437 if (unlikely(!rq
->nr_running
))
5438 idle_balance(cpu
, rq
);
5440 put_prev_task(rq
, prev
);
5441 next
= pick_next_task(rq
);
5443 if (likely(prev
!= next
)) {
5444 sched_info_switch(prev
, next
);
5445 perf_counter_task_sched_out(prev
, next
, cpu
);
5451 context_switch(rq
, prev
, next
); /* unlocks the rq */
5453 * the context switch might have flipped the stack from under
5454 * us, hence refresh the local variables.
5456 cpu
= smp_processor_id();
5459 spin_unlock_irq(&rq
->lock
);
5463 if (unlikely(reacquire_kernel_lock(current
) < 0))
5464 goto need_resched_nonpreemptible
;
5466 preempt_enable_no_resched();
5470 EXPORT_SYMBOL(schedule
);
5474 * Look out! "owner" is an entirely speculative pointer
5475 * access and not reliable.
5477 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
5482 if (!sched_feat(OWNER_SPIN
))
5485 #ifdef CONFIG_DEBUG_PAGEALLOC
5487 * Need to access the cpu field knowing that
5488 * DEBUG_PAGEALLOC could have unmapped it if
5489 * the mutex owner just released it and exited.
5491 if (probe_kernel_address(&owner
->cpu
, cpu
))
5498 * Even if the access succeeded (likely case),
5499 * the cpu field may no longer be valid.
5501 if (cpu
>= nr_cpumask_bits
)
5505 * We need to validate that we can do a
5506 * get_cpu() and that we have the percpu area.
5508 if (!cpu_online(cpu
))
5515 * Owner changed, break to re-assess state.
5517 if (lock
->owner
!= owner
)
5521 * Is that owner really running on that cpu?
5523 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
5533 #ifdef CONFIG_PREEMPT
5535 * this is the entry point to schedule() from in-kernel preemption
5536 * off of preempt_enable. Kernel preemptions off return from interrupt
5537 * occur there and call schedule directly.
5539 asmlinkage
void __sched
preempt_schedule(void)
5541 struct thread_info
*ti
= current_thread_info();
5544 * If there is a non-zero preempt_count or interrupts are disabled,
5545 * we do not want to preempt the current task. Just return..
5547 if (likely(ti
->preempt_count
|| irqs_disabled()))
5551 add_preempt_count(PREEMPT_ACTIVE
);
5553 sub_preempt_count(PREEMPT_ACTIVE
);
5556 * Check again in case we missed a preemption opportunity
5557 * between schedule and now.
5560 } while (need_resched());
5562 EXPORT_SYMBOL(preempt_schedule
);
5565 * this is the entry point to schedule() from kernel preemption
5566 * off of irq context.
5567 * Note, that this is called and return with irqs disabled. This will
5568 * protect us against recursive calling from irq.
5570 asmlinkage
void __sched
preempt_schedule_irq(void)
5572 struct thread_info
*ti
= current_thread_info();
5574 /* Catch callers which need to be fixed */
5575 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
5578 add_preempt_count(PREEMPT_ACTIVE
);
5581 local_irq_disable();
5582 sub_preempt_count(PREEMPT_ACTIVE
);
5585 * Check again in case we missed a preemption opportunity
5586 * between schedule and now.
5589 } while (need_resched());
5592 #endif /* CONFIG_PREEMPT */
5594 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
5597 return try_to_wake_up(curr
->private, mode
, sync
);
5599 EXPORT_SYMBOL(default_wake_function
);
5602 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5603 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5604 * number) then we wake all the non-exclusive tasks and one exclusive task.
5606 * There are circumstances in which we can try to wake a task which has already
5607 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5608 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5610 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
5611 int nr_exclusive
, int sync
, void *key
)
5613 wait_queue_t
*curr
, *next
;
5615 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
5616 unsigned flags
= curr
->flags
;
5618 if (curr
->func(curr
, mode
, sync
, key
) &&
5619 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
5625 * __wake_up - wake up threads blocked on a waitqueue.
5627 * @mode: which threads
5628 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5629 * @key: is directly passed to the wakeup function
5631 * It may be assumed that this function implies a write memory barrier before
5632 * changing the task state if and only if any tasks are woken up.
5634 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
5635 int nr_exclusive
, void *key
)
5637 unsigned long flags
;
5639 spin_lock_irqsave(&q
->lock
, flags
);
5640 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
5641 spin_unlock_irqrestore(&q
->lock
, flags
);
5643 EXPORT_SYMBOL(__wake_up
);
5646 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5648 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
5650 __wake_up_common(q
, mode
, 1, 0, NULL
);
5653 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
5655 __wake_up_common(q
, mode
, 1, 0, key
);
5659 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5661 * @mode: which threads
5662 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5663 * @key: opaque value to be passed to wakeup targets
5665 * The sync wakeup differs that the waker knows that it will schedule
5666 * away soon, so while the target thread will be woken up, it will not
5667 * be migrated to another CPU - ie. the two threads are 'synchronized'
5668 * with each other. This can prevent needless bouncing between CPUs.
5670 * On UP it can prevent extra preemption.
5672 * It may be assumed that this function implies a write memory barrier before
5673 * changing the task state if and only if any tasks are woken up.
5675 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
5676 int nr_exclusive
, void *key
)
5678 unsigned long flags
;
5684 if (unlikely(!nr_exclusive
))
5687 spin_lock_irqsave(&q
->lock
, flags
);
5688 __wake_up_common(q
, mode
, nr_exclusive
, sync
, key
);
5689 spin_unlock_irqrestore(&q
->lock
, flags
);
5691 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
5694 * __wake_up_sync - see __wake_up_sync_key()
5696 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
5698 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
5700 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
5703 * complete: - signals a single thread waiting on this completion
5704 * @x: holds the state of this particular completion
5706 * This will wake up a single thread waiting on this completion. Threads will be
5707 * awakened in the same order in which they were queued.
5709 * See also complete_all(), wait_for_completion() and related routines.
5711 * It may be assumed that this function implies a write memory barrier before
5712 * changing the task state if and only if any tasks are woken up.
5714 void complete(struct completion
*x
)
5716 unsigned long flags
;
5718 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5720 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
5721 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5723 EXPORT_SYMBOL(complete
);
5726 * complete_all: - signals all threads waiting on this completion
5727 * @x: holds the state of this particular completion
5729 * This will wake up all threads waiting on this particular completion event.
5731 * It may be assumed that this function implies a write memory barrier before
5732 * changing the task state if and only if any tasks are woken up.
5734 void complete_all(struct completion
*x
)
5736 unsigned long flags
;
5738 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5739 x
->done
+= UINT_MAX
/2;
5740 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
5741 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5743 EXPORT_SYMBOL(complete_all
);
5745 static inline long __sched
5746 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
5749 DECLARE_WAITQUEUE(wait
, current
);
5751 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
5752 __add_wait_queue_tail(&x
->wait
, &wait
);
5754 if (signal_pending_state(state
, current
)) {
5755 timeout
= -ERESTARTSYS
;
5758 __set_current_state(state
);
5759 spin_unlock_irq(&x
->wait
.lock
);
5760 timeout
= schedule_timeout(timeout
);
5761 spin_lock_irq(&x
->wait
.lock
);
5762 } while (!x
->done
&& timeout
);
5763 __remove_wait_queue(&x
->wait
, &wait
);
5768 return timeout
?: 1;
5772 wait_for_common(struct completion
*x
, long timeout
, int state
)
5776 spin_lock_irq(&x
->wait
.lock
);
5777 timeout
= do_wait_for_common(x
, timeout
, state
);
5778 spin_unlock_irq(&x
->wait
.lock
);
5783 * wait_for_completion: - waits for completion of a task
5784 * @x: holds the state of this particular completion
5786 * This waits to be signaled for completion of a specific task. It is NOT
5787 * interruptible and there is no timeout.
5789 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5790 * and interrupt capability. Also see complete().
5792 void __sched
wait_for_completion(struct completion
*x
)
5794 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
5796 EXPORT_SYMBOL(wait_for_completion
);
5799 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5800 * @x: holds the state of this particular completion
5801 * @timeout: timeout value in jiffies
5803 * This waits for either a completion of a specific task to be signaled or for a
5804 * specified timeout to expire. The timeout is in jiffies. It is not
5807 unsigned long __sched
5808 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
5810 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
5812 EXPORT_SYMBOL(wait_for_completion_timeout
);
5815 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5816 * @x: holds the state of this particular completion
5818 * This waits for completion of a specific task to be signaled. It is
5821 int __sched
wait_for_completion_interruptible(struct completion
*x
)
5823 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
5824 if (t
== -ERESTARTSYS
)
5828 EXPORT_SYMBOL(wait_for_completion_interruptible
);
5831 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5832 * @x: holds the state of this particular completion
5833 * @timeout: timeout value in jiffies
5835 * This waits for either a completion of a specific task to be signaled or for a
5836 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5838 unsigned long __sched
5839 wait_for_completion_interruptible_timeout(struct completion
*x
,
5840 unsigned long timeout
)
5842 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
5844 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
5847 * wait_for_completion_killable: - waits for completion of a task (killable)
5848 * @x: holds the state of this particular completion
5850 * This waits to be signaled for completion of a specific task. It can be
5851 * interrupted by a kill signal.
5853 int __sched
wait_for_completion_killable(struct completion
*x
)
5855 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
5856 if (t
== -ERESTARTSYS
)
5860 EXPORT_SYMBOL(wait_for_completion_killable
);
5863 * try_wait_for_completion - try to decrement a completion without blocking
5864 * @x: completion structure
5866 * Returns: 0 if a decrement cannot be done without blocking
5867 * 1 if a decrement succeeded.
5869 * If a completion is being used as a counting completion,
5870 * attempt to decrement the counter without blocking. This
5871 * enables us to avoid waiting if the resource the completion
5872 * is protecting is not available.
5874 bool try_wait_for_completion(struct completion
*x
)
5878 spin_lock_irq(&x
->wait
.lock
);
5883 spin_unlock_irq(&x
->wait
.lock
);
5886 EXPORT_SYMBOL(try_wait_for_completion
);
5889 * completion_done - Test to see if a completion has any waiters
5890 * @x: completion structure
5892 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5893 * 1 if there are no waiters.
5896 bool completion_done(struct completion
*x
)
5900 spin_lock_irq(&x
->wait
.lock
);
5903 spin_unlock_irq(&x
->wait
.lock
);
5906 EXPORT_SYMBOL(completion_done
);
5909 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5911 unsigned long flags
;
5914 init_waitqueue_entry(&wait
, current
);
5916 __set_current_state(state
);
5918 spin_lock_irqsave(&q
->lock
, flags
);
5919 __add_wait_queue(q
, &wait
);
5920 spin_unlock(&q
->lock
);
5921 timeout
= schedule_timeout(timeout
);
5922 spin_lock_irq(&q
->lock
);
5923 __remove_wait_queue(q
, &wait
);
5924 spin_unlock_irqrestore(&q
->lock
, flags
);
5929 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
5931 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5933 EXPORT_SYMBOL(interruptible_sleep_on
);
5936 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5938 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
5940 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
5942 void __sched
sleep_on(wait_queue_head_t
*q
)
5944 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5946 EXPORT_SYMBOL(sleep_on
);
5948 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5950 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5952 EXPORT_SYMBOL(sleep_on_timeout
);
5954 #ifdef CONFIG_RT_MUTEXES
5957 * rt_mutex_setprio - set the current priority of a task
5959 * @prio: prio value (kernel-internal form)
5961 * This function changes the 'effective' priority of a task. It does
5962 * not touch ->normal_prio like __setscheduler().
5964 * Used by the rt_mutex code to implement priority inheritance logic.
5966 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
5968 unsigned long flags
;
5969 int oldprio
, on_rq
, running
;
5971 const struct sched_class
*prev_class
= p
->sched_class
;
5973 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
5975 rq
= task_rq_lock(p
, &flags
);
5976 update_rq_clock(rq
);
5979 on_rq
= p
->se
.on_rq
;
5980 running
= task_current(rq
, p
);
5982 dequeue_task(rq
, p
, 0);
5984 p
->sched_class
->put_prev_task(rq
, p
);
5987 p
->sched_class
= &rt_sched_class
;
5989 p
->sched_class
= &fair_sched_class
;
5994 p
->sched_class
->set_curr_task(rq
);
5996 enqueue_task(rq
, p
, 0);
5998 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6000 task_rq_unlock(rq
, &flags
);
6005 void set_user_nice(struct task_struct
*p
, long nice
)
6007 int old_prio
, delta
, on_rq
;
6008 unsigned long flags
;
6011 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
6014 * We have to be careful, if called from sys_setpriority(),
6015 * the task might be in the middle of scheduling on another CPU.
6017 rq
= task_rq_lock(p
, &flags
);
6018 update_rq_clock(rq
);
6020 * The RT priorities are set via sched_setscheduler(), but we still
6021 * allow the 'normal' nice value to be set - but as expected
6022 * it wont have any effect on scheduling until the task is
6023 * SCHED_FIFO/SCHED_RR:
6025 if (task_has_rt_policy(p
)) {
6026 p
->static_prio
= NICE_TO_PRIO(nice
);
6029 on_rq
= p
->se
.on_rq
;
6031 dequeue_task(rq
, p
, 0);
6033 p
->static_prio
= NICE_TO_PRIO(nice
);
6036 p
->prio
= effective_prio(p
);
6037 delta
= p
->prio
- old_prio
;
6040 enqueue_task(rq
, p
, 0);
6042 * If the task increased its priority or is running and
6043 * lowered its priority, then reschedule its CPU:
6045 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
6046 resched_task(rq
->curr
);
6049 task_rq_unlock(rq
, &flags
);
6051 EXPORT_SYMBOL(set_user_nice
);
6054 * can_nice - check if a task can reduce its nice value
6058 int can_nice(const struct task_struct
*p
, const int nice
)
6060 /* convert nice value [19,-20] to rlimit style value [1,40] */
6061 int nice_rlim
= 20 - nice
;
6063 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
6064 capable(CAP_SYS_NICE
));
6067 #ifdef __ARCH_WANT_SYS_NICE
6070 * sys_nice - change the priority of the current process.
6071 * @increment: priority increment
6073 * sys_setpriority is a more generic, but much slower function that
6074 * does similar things.
6076 SYSCALL_DEFINE1(nice
, int, increment
)
6081 * Setpriority might change our priority at the same moment.
6082 * We don't have to worry. Conceptually one call occurs first
6083 * and we have a single winner.
6085 if (increment
< -40)
6090 nice
= TASK_NICE(current
) + increment
;
6096 if (increment
< 0 && !can_nice(current
, nice
))
6099 retval
= security_task_setnice(current
, nice
);
6103 set_user_nice(current
, nice
);
6110 * task_prio - return the priority value of a given task.
6111 * @p: the task in question.
6113 * This is the priority value as seen by users in /proc.
6114 * RT tasks are offset by -200. Normal tasks are centered
6115 * around 0, value goes from -16 to +15.
6117 int task_prio(const struct task_struct
*p
)
6119 return p
->prio
- MAX_RT_PRIO
;
6123 * task_nice - return the nice value of a given task.
6124 * @p: the task in question.
6126 int task_nice(const struct task_struct
*p
)
6128 return TASK_NICE(p
);
6130 EXPORT_SYMBOL(task_nice
);
6133 * idle_cpu - is a given cpu idle currently?
6134 * @cpu: the processor in question.
6136 int idle_cpu(int cpu
)
6138 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
6142 * idle_task - return the idle task for a given cpu.
6143 * @cpu: the processor in question.
6145 struct task_struct
*idle_task(int cpu
)
6147 return cpu_rq(cpu
)->idle
;
6151 * find_process_by_pid - find a process with a matching PID value.
6152 * @pid: the pid in question.
6154 static struct task_struct
*find_process_by_pid(pid_t pid
)
6156 return pid
? find_task_by_vpid(pid
) : current
;
6159 /* Actually do priority change: must hold rq lock. */
6161 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
6163 BUG_ON(p
->se
.on_rq
);
6166 switch (p
->policy
) {
6170 p
->sched_class
= &fair_sched_class
;
6174 p
->sched_class
= &rt_sched_class
;
6178 p
->rt_priority
= prio
;
6179 p
->normal_prio
= normal_prio(p
);
6180 /* we are holding p->pi_lock already */
6181 p
->prio
= rt_mutex_getprio(p
);
6186 * check the target process has a UID that matches the current process's
6188 static bool check_same_owner(struct task_struct
*p
)
6190 const struct cred
*cred
= current_cred(), *pcred
;
6194 pcred
= __task_cred(p
);
6195 match
= (cred
->euid
== pcred
->euid
||
6196 cred
->euid
== pcred
->uid
);
6201 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
6202 struct sched_param
*param
, bool user
)
6204 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
6205 unsigned long flags
;
6206 const struct sched_class
*prev_class
= p
->sched_class
;
6210 /* may grab non-irq protected spin_locks */
6211 BUG_ON(in_interrupt());
6213 /* double check policy once rq lock held */
6215 reset_on_fork
= p
->sched_reset_on_fork
;
6216 policy
= oldpolicy
= p
->policy
;
6218 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
6219 policy
&= ~SCHED_RESET_ON_FORK
;
6221 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
6222 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
6223 policy
!= SCHED_IDLE
)
6228 * Valid priorities for SCHED_FIFO and SCHED_RR are
6229 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
6230 * SCHED_BATCH and SCHED_IDLE is 0.
6232 if (param
->sched_priority
< 0 ||
6233 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
6234 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
6236 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
6240 * Allow unprivileged RT tasks to decrease priority:
6242 if (user
&& !capable(CAP_SYS_NICE
)) {
6243 if (rt_policy(policy
)) {
6244 unsigned long rlim_rtprio
;
6246 if (!lock_task_sighand(p
, &flags
))
6248 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
6249 unlock_task_sighand(p
, &flags
);
6251 /* can't set/change the rt policy */
6252 if (policy
!= p
->policy
&& !rlim_rtprio
)
6255 /* can't increase priority */
6256 if (param
->sched_priority
> p
->rt_priority
&&
6257 param
->sched_priority
> rlim_rtprio
)
6261 * Like positive nice levels, dont allow tasks to
6262 * move out of SCHED_IDLE either:
6264 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
6267 /* can't change other user's priorities */
6268 if (!check_same_owner(p
))
6271 /* Normal users shall not reset the sched_reset_on_fork flag */
6272 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
6277 #ifdef CONFIG_RT_GROUP_SCHED
6279 * Do not allow realtime tasks into groups that have no runtime
6282 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
6283 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
6287 retval
= security_task_setscheduler(p
, policy
, param
);
6293 * make sure no PI-waiters arrive (or leave) while we are
6294 * changing the priority of the task:
6296 spin_lock_irqsave(&p
->pi_lock
, flags
);
6298 * To be able to change p->policy safely, the apropriate
6299 * runqueue lock must be held.
6301 rq
= __task_rq_lock(p
);
6302 /* recheck policy now with rq lock held */
6303 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
6304 policy
= oldpolicy
= -1;
6305 __task_rq_unlock(rq
);
6306 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6309 update_rq_clock(rq
);
6310 on_rq
= p
->se
.on_rq
;
6311 running
= task_current(rq
, p
);
6313 deactivate_task(rq
, p
, 0);
6315 p
->sched_class
->put_prev_task(rq
, p
);
6317 p
->sched_reset_on_fork
= reset_on_fork
;
6320 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
6323 p
->sched_class
->set_curr_task(rq
);
6325 activate_task(rq
, p
, 0);
6327 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6329 __task_rq_unlock(rq
);
6330 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6332 rt_mutex_adjust_pi(p
);
6338 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
6339 * @p: the task in question.
6340 * @policy: new policy.
6341 * @param: structure containing the new RT priority.
6343 * NOTE that the task may be already dead.
6345 int sched_setscheduler(struct task_struct
*p
, int policy
,
6346 struct sched_param
*param
)
6348 return __sched_setscheduler(p
, policy
, param
, true);
6350 EXPORT_SYMBOL_GPL(sched_setscheduler
);
6353 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
6354 * @p: the task in question.
6355 * @policy: new policy.
6356 * @param: structure containing the new RT priority.
6358 * Just like sched_setscheduler, only don't bother checking if the
6359 * current context has permission. For example, this is needed in
6360 * stop_machine(): we create temporary high priority worker threads,
6361 * but our caller might not have that capability.
6363 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
6364 struct sched_param
*param
)
6366 return __sched_setscheduler(p
, policy
, param
, false);
6370 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
6372 struct sched_param lparam
;
6373 struct task_struct
*p
;
6376 if (!param
|| pid
< 0)
6378 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
6383 p
= find_process_by_pid(pid
);
6385 retval
= sched_setscheduler(p
, policy
, &lparam
);
6392 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
6393 * @pid: the pid in question.
6394 * @policy: new policy.
6395 * @param: structure containing the new RT priority.
6397 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
6398 struct sched_param __user
*, param
)
6400 /* negative values for policy are not valid */
6404 return do_sched_setscheduler(pid
, policy
, param
);
6408 * sys_sched_setparam - set/change the RT priority of a thread
6409 * @pid: the pid in question.
6410 * @param: structure containing the new RT priority.
6412 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6414 return do_sched_setscheduler(pid
, -1, param
);
6418 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6419 * @pid: the pid in question.
6421 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
6423 struct task_struct
*p
;
6430 read_lock(&tasklist_lock
);
6431 p
= find_process_by_pid(pid
);
6433 retval
= security_task_getscheduler(p
);
6436 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
6438 read_unlock(&tasklist_lock
);
6443 * sys_sched_getparam - get the RT priority of a thread
6444 * @pid: the pid in question.
6445 * @param: structure containing the RT priority.
6447 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6449 struct sched_param lp
;
6450 struct task_struct
*p
;
6453 if (!param
|| pid
< 0)
6456 read_lock(&tasklist_lock
);
6457 p
= find_process_by_pid(pid
);
6462 retval
= security_task_getscheduler(p
);
6466 lp
.sched_priority
= p
->rt_priority
;
6467 read_unlock(&tasklist_lock
);
6470 * This one might sleep, we cannot do it with a spinlock held ...
6472 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
6477 read_unlock(&tasklist_lock
);
6481 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
6483 cpumask_var_t cpus_allowed
, new_mask
;
6484 struct task_struct
*p
;
6488 read_lock(&tasklist_lock
);
6490 p
= find_process_by_pid(pid
);
6492 read_unlock(&tasklist_lock
);
6498 * It is not safe to call set_cpus_allowed with the
6499 * tasklist_lock held. We will bump the task_struct's
6500 * usage count and then drop tasklist_lock.
6503 read_unlock(&tasklist_lock
);
6505 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
6509 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
6511 goto out_free_cpus_allowed
;
6514 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
6517 retval
= security_task_setscheduler(p
, 0, NULL
);
6521 cpuset_cpus_allowed(p
, cpus_allowed
);
6522 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
6524 retval
= set_cpus_allowed_ptr(p
, new_mask
);
6527 cpuset_cpus_allowed(p
, cpus_allowed
);
6528 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
6530 * We must have raced with a concurrent cpuset
6531 * update. Just reset the cpus_allowed to the
6532 * cpuset's cpus_allowed
6534 cpumask_copy(new_mask
, cpus_allowed
);
6539 free_cpumask_var(new_mask
);
6540 out_free_cpus_allowed
:
6541 free_cpumask_var(cpus_allowed
);
6548 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
6549 struct cpumask
*new_mask
)
6551 if (len
< cpumask_size())
6552 cpumask_clear(new_mask
);
6553 else if (len
> cpumask_size())
6554 len
= cpumask_size();
6556 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
6560 * sys_sched_setaffinity - set the cpu affinity of a process
6561 * @pid: pid of the process
6562 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6563 * @user_mask_ptr: user-space pointer to the new cpu mask
6565 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
6566 unsigned long __user
*, user_mask_ptr
)
6568 cpumask_var_t new_mask
;
6571 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
6574 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
6576 retval
= sched_setaffinity(pid
, new_mask
);
6577 free_cpumask_var(new_mask
);
6581 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
6583 struct task_struct
*p
;
6587 read_lock(&tasklist_lock
);
6590 p
= find_process_by_pid(pid
);
6594 retval
= security_task_getscheduler(p
);
6598 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
6601 read_unlock(&tasklist_lock
);
6608 * sys_sched_getaffinity - get the cpu affinity of a process
6609 * @pid: pid of the process
6610 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6611 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6613 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
6614 unsigned long __user
*, user_mask_ptr
)
6619 if (len
< cpumask_size())
6622 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
6625 ret
= sched_getaffinity(pid
, mask
);
6627 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
6630 ret
= cpumask_size();
6632 free_cpumask_var(mask
);
6638 * sys_sched_yield - yield the current processor to other threads.
6640 * This function yields the current CPU to other tasks. If there are no
6641 * other threads running on this CPU then this function will return.
6643 SYSCALL_DEFINE0(sched_yield
)
6645 struct rq
*rq
= this_rq_lock();
6647 schedstat_inc(rq
, yld_count
);
6648 current
->sched_class
->yield_task(rq
);
6651 * Since we are going to call schedule() anyway, there's
6652 * no need to preempt or enable interrupts:
6654 __release(rq
->lock
);
6655 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
6656 _raw_spin_unlock(&rq
->lock
);
6657 preempt_enable_no_resched();
6664 static inline int should_resched(void)
6666 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
6669 static void __cond_resched(void)
6671 add_preempt_count(PREEMPT_ACTIVE
);
6673 sub_preempt_count(PREEMPT_ACTIVE
);
6676 int __sched
_cond_resched(void)
6678 if (should_resched()) {
6684 EXPORT_SYMBOL(_cond_resched
);
6687 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
6688 * call schedule, and on return reacquire the lock.
6690 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6691 * operations here to prevent schedule() from being called twice (once via
6692 * spin_unlock(), once by hand).
6694 int __cond_resched_lock(spinlock_t
*lock
)
6696 int resched
= should_resched();
6699 if (spin_needbreak(lock
) || resched
) {
6710 EXPORT_SYMBOL(__cond_resched_lock
);
6712 int __sched
__cond_resched_softirq(void)
6714 BUG_ON(!in_softirq());
6716 if (should_resched()) {
6724 EXPORT_SYMBOL(__cond_resched_softirq
);
6727 * yield - yield the current processor to other threads.
6729 * This is a shortcut for kernel-space yielding - it marks the
6730 * thread runnable and calls sys_sched_yield().
6732 void __sched
yield(void)
6734 set_current_state(TASK_RUNNING
);
6737 EXPORT_SYMBOL(yield
);
6740 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6741 * that process accounting knows that this is a task in IO wait state.
6743 * But don't do that if it is a deliberate, throttling IO wait (this task
6744 * has set its backing_dev_info: the queue against which it should throttle)
6746 void __sched
io_schedule(void)
6748 struct rq
*rq
= raw_rq();
6750 delayacct_blkio_start();
6751 atomic_inc(&rq
->nr_iowait
);
6753 atomic_dec(&rq
->nr_iowait
);
6754 delayacct_blkio_end();
6756 EXPORT_SYMBOL(io_schedule
);
6758 long __sched
io_schedule_timeout(long timeout
)
6760 struct rq
*rq
= raw_rq();
6763 delayacct_blkio_start();
6764 atomic_inc(&rq
->nr_iowait
);
6765 ret
= schedule_timeout(timeout
);
6766 atomic_dec(&rq
->nr_iowait
);
6767 delayacct_blkio_end();
6772 * sys_sched_get_priority_max - return maximum RT priority.
6773 * @policy: scheduling class.
6775 * this syscall returns the maximum rt_priority that can be used
6776 * by a given scheduling class.
6778 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
6785 ret
= MAX_USER_RT_PRIO
-1;
6797 * sys_sched_get_priority_min - return minimum RT priority.
6798 * @policy: scheduling class.
6800 * this syscall returns the minimum rt_priority that can be used
6801 * by a given scheduling class.
6803 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
6821 * sys_sched_rr_get_interval - return the default timeslice of a process.
6822 * @pid: pid of the process.
6823 * @interval: userspace pointer to the timeslice value.
6825 * this syscall writes the default timeslice value of a given process
6826 * into the user-space timespec buffer. A value of '0' means infinity.
6828 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
6829 struct timespec __user
*, interval
)
6831 struct task_struct
*p
;
6832 unsigned int time_slice
;
6840 read_lock(&tasklist_lock
);
6841 p
= find_process_by_pid(pid
);
6845 retval
= security_task_getscheduler(p
);
6850 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6851 * tasks that are on an otherwise idle runqueue:
6854 if (p
->policy
== SCHED_RR
) {
6855 time_slice
= DEF_TIMESLICE
;
6856 } else if (p
->policy
!= SCHED_FIFO
) {
6857 struct sched_entity
*se
= &p
->se
;
6858 unsigned long flags
;
6861 rq
= task_rq_lock(p
, &flags
);
6862 if (rq
->cfs
.load
.weight
)
6863 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
6864 task_rq_unlock(rq
, &flags
);
6866 read_unlock(&tasklist_lock
);
6867 jiffies_to_timespec(time_slice
, &t
);
6868 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
6872 read_unlock(&tasklist_lock
);
6876 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
6878 void sched_show_task(struct task_struct
*p
)
6880 unsigned long free
= 0;
6883 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
6884 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
6885 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
6886 #if BITS_PER_LONG == 32
6887 if (state
== TASK_RUNNING
)
6888 printk(KERN_CONT
" running ");
6890 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
6892 if (state
== TASK_RUNNING
)
6893 printk(KERN_CONT
" running task ");
6895 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
6897 #ifdef CONFIG_DEBUG_STACK_USAGE
6898 free
= stack_not_used(p
);
6900 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
6901 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
6902 (unsigned long)task_thread_info(p
)->flags
);
6904 show_stack(p
, NULL
);
6907 void show_state_filter(unsigned long state_filter
)
6909 struct task_struct
*g
, *p
;
6911 #if BITS_PER_LONG == 32
6913 " task PC stack pid father\n");
6916 " task PC stack pid father\n");
6918 read_lock(&tasklist_lock
);
6919 do_each_thread(g
, p
) {
6921 * reset the NMI-timeout, listing all files on a slow
6922 * console might take alot of time:
6924 touch_nmi_watchdog();
6925 if (!state_filter
|| (p
->state
& state_filter
))
6927 } while_each_thread(g
, p
);
6929 touch_all_softlockup_watchdogs();
6931 #ifdef CONFIG_SCHED_DEBUG
6932 sysrq_sched_debug_show();
6934 read_unlock(&tasklist_lock
);
6936 * Only show locks if all tasks are dumped:
6938 if (state_filter
== -1)
6939 debug_show_all_locks();
6942 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6944 idle
->sched_class
= &idle_sched_class
;
6948 * init_idle - set up an idle thread for a given CPU
6949 * @idle: task in question
6950 * @cpu: cpu the idle task belongs to
6952 * NOTE: this function does not set the idle thread's NEED_RESCHED
6953 * flag, to make booting more robust.
6955 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6957 struct rq
*rq
= cpu_rq(cpu
);
6958 unsigned long flags
;
6960 spin_lock_irqsave(&rq
->lock
, flags
);
6963 idle
->se
.exec_start
= sched_clock();
6965 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
6966 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
6967 __set_task_cpu(idle
, cpu
);
6969 rq
->curr
= rq
->idle
= idle
;
6970 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6973 spin_unlock_irqrestore(&rq
->lock
, flags
);
6975 /* Set the preempt count _outside_ the spinlocks! */
6976 #if defined(CONFIG_PREEMPT)
6977 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
6979 task_thread_info(idle
)->preempt_count
= 0;
6982 * The idle tasks have their own, simple scheduling class:
6984 idle
->sched_class
= &idle_sched_class
;
6985 ftrace_graph_init_task(idle
);
6989 * In a system that switches off the HZ timer nohz_cpu_mask
6990 * indicates which cpus entered this state. This is used
6991 * in the rcu update to wait only for active cpus. For system
6992 * which do not switch off the HZ timer nohz_cpu_mask should
6993 * always be CPU_BITS_NONE.
6995 cpumask_var_t nohz_cpu_mask
;
6998 * Increase the granularity value when there are more CPUs,
6999 * because with more CPUs the 'effective latency' as visible
7000 * to users decreases. But the relationship is not linear,
7001 * so pick a second-best guess by going with the log2 of the
7004 * This idea comes from the SD scheduler of Con Kolivas:
7006 static inline void sched_init_granularity(void)
7008 unsigned int factor
= 1 + ilog2(num_online_cpus());
7009 const unsigned long limit
= 200000000;
7011 sysctl_sched_min_granularity
*= factor
;
7012 if (sysctl_sched_min_granularity
> limit
)
7013 sysctl_sched_min_granularity
= limit
;
7015 sysctl_sched_latency
*= factor
;
7016 if (sysctl_sched_latency
> limit
)
7017 sysctl_sched_latency
= limit
;
7019 sysctl_sched_wakeup_granularity
*= factor
;
7021 sysctl_sched_shares_ratelimit
*= factor
;
7026 * This is how migration works:
7028 * 1) we queue a struct migration_req structure in the source CPU's
7029 * runqueue and wake up that CPU's migration thread.
7030 * 2) we down() the locked semaphore => thread blocks.
7031 * 3) migration thread wakes up (implicitly it forces the migrated
7032 * thread off the CPU)
7033 * 4) it gets the migration request and checks whether the migrated
7034 * task is still in the wrong runqueue.
7035 * 5) if it's in the wrong runqueue then the migration thread removes
7036 * it and puts it into the right queue.
7037 * 6) migration thread up()s the semaphore.
7038 * 7) we wake up and the migration is done.
7042 * Change a given task's CPU affinity. Migrate the thread to a
7043 * proper CPU and schedule it away if the CPU it's executing on
7044 * is removed from the allowed bitmask.
7046 * NOTE: the caller must have a valid reference to the task, the
7047 * task must not exit() & deallocate itself prematurely. The
7048 * call is not atomic; no spinlocks may be held.
7050 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
7052 struct migration_req req
;
7053 unsigned long flags
;
7057 rq
= task_rq_lock(p
, &flags
);
7058 if (!cpumask_intersects(new_mask
, cpu_online_mask
)) {
7063 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
7064 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
7069 if (p
->sched_class
->set_cpus_allowed
)
7070 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
7072 cpumask_copy(&p
->cpus_allowed
, new_mask
);
7073 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
7076 /* Can the task run on the task's current CPU? If so, we're done */
7077 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
7080 if (migrate_task(p
, cpumask_any_and(cpu_online_mask
, new_mask
), &req
)) {
7081 /* Need help from migration thread: drop lock and wait. */
7082 struct task_struct
*mt
= rq
->migration_thread
;
7084 get_task_struct(mt
);
7085 task_rq_unlock(rq
, &flags
);
7086 wake_up_process(rq
->migration_thread
);
7087 put_task_struct(mt
);
7088 wait_for_completion(&req
.done
);
7089 tlb_migrate_finish(p
->mm
);
7093 task_rq_unlock(rq
, &flags
);
7097 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
7100 * Move (not current) task off this cpu, onto dest cpu. We're doing
7101 * this because either it can't run here any more (set_cpus_allowed()
7102 * away from this CPU, or CPU going down), or because we're
7103 * attempting to rebalance this task on exec (sched_exec).
7105 * So we race with normal scheduler movements, but that's OK, as long
7106 * as the task is no longer on this CPU.
7108 * Returns non-zero if task was successfully migrated.
7110 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7112 struct rq
*rq_dest
, *rq_src
;
7115 if (unlikely(!cpu_active(dest_cpu
)))
7118 rq_src
= cpu_rq(src_cpu
);
7119 rq_dest
= cpu_rq(dest_cpu
);
7121 double_rq_lock(rq_src
, rq_dest
);
7122 /* Already moved. */
7123 if (task_cpu(p
) != src_cpu
)
7125 /* Affinity changed (again). */
7126 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7129 on_rq
= p
->se
.on_rq
;
7131 deactivate_task(rq_src
, p
, 0);
7133 set_task_cpu(p
, dest_cpu
);
7135 activate_task(rq_dest
, p
, 0);
7136 check_preempt_curr(rq_dest
, p
, 0);
7141 double_rq_unlock(rq_src
, rq_dest
);
7146 * migration_thread - this is a highprio system thread that performs
7147 * thread migration by bumping thread off CPU then 'pushing' onto
7150 static int migration_thread(void *data
)
7152 int cpu
= (long)data
;
7156 BUG_ON(rq
->migration_thread
!= current
);
7158 set_current_state(TASK_INTERRUPTIBLE
);
7159 while (!kthread_should_stop()) {
7160 struct migration_req
*req
;
7161 struct list_head
*head
;
7163 spin_lock_irq(&rq
->lock
);
7165 if (cpu_is_offline(cpu
)) {
7166 spin_unlock_irq(&rq
->lock
);
7170 if (rq
->active_balance
) {
7171 active_load_balance(rq
, cpu
);
7172 rq
->active_balance
= 0;
7175 head
= &rq
->migration_queue
;
7177 if (list_empty(head
)) {
7178 spin_unlock_irq(&rq
->lock
);
7180 set_current_state(TASK_INTERRUPTIBLE
);
7183 req
= list_entry(head
->next
, struct migration_req
, list
);
7184 list_del_init(head
->next
);
7186 spin_unlock(&rq
->lock
);
7187 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
7190 complete(&req
->done
);
7192 __set_current_state(TASK_RUNNING
);
7197 #ifdef CONFIG_HOTPLUG_CPU
7199 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7203 local_irq_disable();
7204 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
7210 * Figure out where task on dead CPU should go, use force if necessary.
7212 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
7215 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(dead_cpu
));
7218 /* Look for allowed, online CPU in same node. */
7219 for_each_cpu_and(dest_cpu
, nodemask
, cpu_online_mask
)
7220 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7223 /* Any allowed, online CPU? */
7224 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_online_mask
);
7225 if (dest_cpu
< nr_cpu_ids
)
7228 /* No more Mr. Nice Guy. */
7229 if (dest_cpu
>= nr_cpu_ids
) {
7230 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
7231 dest_cpu
= cpumask_any_and(cpu_online_mask
, &p
->cpus_allowed
);
7234 * Don't tell them about moving exiting tasks or
7235 * kernel threads (both mm NULL), since they never
7238 if (p
->mm
&& printk_ratelimit()) {
7239 printk(KERN_INFO
"process %d (%s) no "
7240 "longer affine to cpu%d\n",
7241 task_pid_nr(p
), p
->comm
, dead_cpu
);
7246 /* It can have affinity changed while we were choosing. */
7247 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
7252 * While a dead CPU has no uninterruptible tasks queued at this point,
7253 * it might still have a nonzero ->nr_uninterruptible counter, because
7254 * for performance reasons the counter is not stricly tracking tasks to
7255 * their home CPUs. So we just add the counter to another CPU's counter,
7256 * to keep the global sum constant after CPU-down:
7258 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
7260 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_online_mask
));
7261 unsigned long flags
;
7263 local_irq_save(flags
);
7264 double_rq_lock(rq_src
, rq_dest
);
7265 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
7266 rq_src
->nr_uninterruptible
= 0;
7267 double_rq_unlock(rq_src
, rq_dest
);
7268 local_irq_restore(flags
);
7271 /* Run through task list and migrate tasks from the dead cpu. */
7272 static void migrate_live_tasks(int src_cpu
)
7274 struct task_struct
*p
, *t
;
7276 read_lock(&tasklist_lock
);
7278 do_each_thread(t
, p
) {
7282 if (task_cpu(p
) == src_cpu
)
7283 move_task_off_dead_cpu(src_cpu
, p
);
7284 } while_each_thread(t
, p
);
7286 read_unlock(&tasklist_lock
);
7290 * Schedules idle task to be the next runnable task on current CPU.
7291 * It does so by boosting its priority to highest possible.
7292 * Used by CPU offline code.
7294 void sched_idle_next(void)
7296 int this_cpu
= smp_processor_id();
7297 struct rq
*rq
= cpu_rq(this_cpu
);
7298 struct task_struct
*p
= rq
->idle
;
7299 unsigned long flags
;
7301 /* cpu has to be offline */
7302 BUG_ON(cpu_online(this_cpu
));
7305 * Strictly not necessary since rest of the CPUs are stopped by now
7306 * and interrupts disabled on the current cpu.
7308 spin_lock_irqsave(&rq
->lock
, flags
);
7310 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7312 update_rq_clock(rq
);
7313 activate_task(rq
, p
, 0);
7315 spin_unlock_irqrestore(&rq
->lock
, flags
);
7319 * Ensures that the idle task is using init_mm right before its cpu goes
7322 void idle_task_exit(void)
7324 struct mm_struct
*mm
= current
->active_mm
;
7326 BUG_ON(cpu_online(smp_processor_id()));
7329 switch_mm(mm
, &init_mm
, current
);
7333 /* called under rq->lock with disabled interrupts */
7334 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
7336 struct rq
*rq
= cpu_rq(dead_cpu
);
7338 /* Must be exiting, otherwise would be on tasklist. */
7339 BUG_ON(!p
->exit_state
);
7341 /* Cannot have done final schedule yet: would have vanished. */
7342 BUG_ON(p
->state
== TASK_DEAD
);
7347 * Drop lock around migration; if someone else moves it,
7348 * that's OK. No task can be added to this CPU, so iteration is
7351 spin_unlock_irq(&rq
->lock
);
7352 move_task_off_dead_cpu(dead_cpu
, p
);
7353 spin_lock_irq(&rq
->lock
);
7358 /* release_task() removes task from tasklist, so we won't find dead tasks. */
7359 static void migrate_dead_tasks(unsigned int dead_cpu
)
7361 struct rq
*rq
= cpu_rq(dead_cpu
);
7362 struct task_struct
*next
;
7365 if (!rq
->nr_running
)
7367 update_rq_clock(rq
);
7368 next
= pick_next_task(rq
);
7371 next
->sched_class
->put_prev_task(rq
, next
);
7372 migrate_dead(dead_cpu
, next
);
7378 * remove the tasks which were accounted by rq from calc_load_tasks.
7380 static void calc_global_load_remove(struct rq
*rq
)
7382 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
7383 rq
->calc_load_active
= 0;
7385 #endif /* CONFIG_HOTPLUG_CPU */
7387 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
7389 static struct ctl_table sd_ctl_dir
[] = {
7391 .procname
= "sched_domain",
7397 static struct ctl_table sd_ctl_root
[] = {
7399 .ctl_name
= CTL_KERN
,
7400 .procname
= "kernel",
7402 .child
= sd_ctl_dir
,
7407 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
7409 struct ctl_table
*entry
=
7410 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
7415 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
7417 struct ctl_table
*entry
;
7420 * In the intermediate directories, both the child directory and
7421 * procname are dynamically allocated and could fail but the mode
7422 * will always be set. In the lowest directory the names are
7423 * static strings and all have proc handlers.
7425 for (entry
= *tablep
; entry
->mode
; entry
++) {
7427 sd_free_ctl_entry(&entry
->child
);
7428 if (entry
->proc_handler
== NULL
)
7429 kfree(entry
->procname
);
7437 set_table_entry(struct ctl_table
*entry
,
7438 const char *procname
, void *data
, int maxlen
,
7439 mode_t mode
, proc_handler
*proc_handler
)
7441 entry
->procname
= procname
;
7443 entry
->maxlen
= maxlen
;
7445 entry
->proc_handler
= proc_handler
;
7448 static struct ctl_table
*
7449 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
7451 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
7456 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
7457 sizeof(long), 0644, proc_doulongvec_minmax
);
7458 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
7459 sizeof(long), 0644, proc_doulongvec_minmax
);
7460 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
7461 sizeof(int), 0644, proc_dointvec_minmax
);
7462 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
7463 sizeof(int), 0644, proc_dointvec_minmax
);
7464 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
7465 sizeof(int), 0644, proc_dointvec_minmax
);
7466 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
7467 sizeof(int), 0644, proc_dointvec_minmax
);
7468 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
7469 sizeof(int), 0644, proc_dointvec_minmax
);
7470 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
7471 sizeof(int), 0644, proc_dointvec_minmax
);
7472 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
7473 sizeof(int), 0644, proc_dointvec_minmax
);
7474 set_table_entry(&table
[9], "cache_nice_tries",
7475 &sd
->cache_nice_tries
,
7476 sizeof(int), 0644, proc_dointvec_minmax
);
7477 set_table_entry(&table
[10], "flags", &sd
->flags
,
7478 sizeof(int), 0644, proc_dointvec_minmax
);
7479 set_table_entry(&table
[11], "name", sd
->name
,
7480 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
7481 /* &table[12] is terminator */
7486 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
7488 struct ctl_table
*entry
, *table
;
7489 struct sched_domain
*sd
;
7490 int domain_num
= 0, i
;
7493 for_each_domain(cpu
, sd
)
7495 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
7500 for_each_domain(cpu
, sd
) {
7501 snprintf(buf
, 32, "domain%d", i
);
7502 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7504 entry
->child
= sd_alloc_ctl_domain_table(sd
);
7511 static struct ctl_table_header
*sd_sysctl_header
;
7512 static void register_sched_domain_sysctl(void)
7514 int i
, cpu_num
= num_online_cpus();
7515 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
7518 WARN_ON(sd_ctl_dir
[0].child
);
7519 sd_ctl_dir
[0].child
= entry
;
7524 for_each_online_cpu(i
) {
7525 snprintf(buf
, 32, "cpu%d", i
);
7526 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7528 entry
->child
= sd_alloc_ctl_cpu_table(i
);
7532 WARN_ON(sd_sysctl_header
);
7533 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
7536 /* may be called multiple times per register */
7537 static void unregister_sched_domain_sysctl(void)
7539 if (sd_sysctl_header
)
7540 unregister_sysctl_table(sd_sysctl_header
);
7541 sd_sysctl_header
= NULL
;
7542 if (sd_ctl_dir
[0].child
)
7543 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
7546 static void register_sched_domain_sysctl(void)
7549 static void unregister_sched_domain_sysctl(void)
7554 static void set_rq_online(struct rq
*rq
)
7557 const struct sched_class
*class;
7559 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
7562 for_each_class(class) {
7563 if (class->rq_online
)
7564 class->rq_online(rq
);
7569 static void set_rq_offline(struct rq
*rq
)
7572 const struct sched_class
*class;
7574 for_each_class(class) {
7575 if (class->rq_offline
)
7576 class->rq_offline(rq
);
7579 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
7585 * migration_call - callback that gets triggered when a CPU is added.
7586 * Here we can start up the necessary migration thread for the new CPU.
7588 static int __cpuinit
7589 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
7591 struct task_struct
*p
;
7592 int cpu
= (long)hcpu
;
7593 unsigned long flags
;
7598 case CPU_UP_PREPARE
:
7599 case CPU_UP_PREPARE_FROZEN
:
7600 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
7603 kthread_bind(p
, cpu
);
7604 /* Must be high prio: stop_machine expects to yield to it. */
7605 rq
= task_rq_lock(p
, &flags
);
7606 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7607 task_rq_unlock(rq
, &flags
);
7609 cpu_rq(cpu
)->migration_thread
= p
;
7610 rq
->calc_load_update
= calc_load_update
;
7614 case CPU_ONLINE_FROZEN
:
7615 /* Strictly unnecessary, as first user will wake it. */
7616 wake_up_process(cpu_rq(cpu
)->migration_thread
);
7618 /* Update our root-domain */
7620 spin_lock_irqsave(&rq
->lock
, flags
);
7622 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7626 spin_unlock_irqrestore(&rq
->lock
, flags
);
7629 #ifdef CONFIG_HOTPLUG_CPU
7630 case CPU_UP_CANCELED
:
7631 case CPU_UP_CANCELED_FROZEN
:
7632 if (!cpu_rq(cpu
)->migration_thread
)
7634 /* Unbind it from offline cpu so it can run. Fall thru. */
7635 kthread_bind(cpu_rq(cpu
)->migration_thread
,
7636 cpumask_any(cpu_online_mask
));
7637 kthread_stop(cpu_rq(cpu
)->migration_thread
);
7638 put_task_struct(cpu_rq(cpu
)->migration_thread
);
7639 cpu_rq(cpu
)->migration_thread
= NULL
;
7643 case CPU_DEAD_FROZEN
:
7644 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7645 migrate_live_tasks(cpu
);
7647 kthread_stop(rq
->migration_thread
);
7648 put_task_struct(rq
->migration_thread
);
7649 rq
->migration_thread
= NULL
;
7650 /* Idle task back to normal (off runqueue, low prio) */
7651 spin_lock_irq(&rq
->lock
);
7652 update_rq_clock(rq
);
7653 deactivate_task(rq
, rq
->idle
, 0);
7654 rq
->idle
->static_prio
= MAX_PRIO
;
7655 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
7656 rq
->idle
->sched_class
= &idle_sched_class
;
7657 migrate_dead_tasks(cpu
);
7658 spin_unlock_irq(&rq
->lock
);
7660 migrate_nr_uninterruptible(rq
);
7661 BUG_ON(rq
->nr_running
!= 0);
7662 calc_global_load_remove(rq
);
7664 * No need to migrate the tasks: it was best-effort if
7665 * they didn't take sched_hotcpu_mutex. Just wake up
7668 spin_lock_irq(&rq
->lock
);
7669 while (!list_empty(&rq
->migration_queue
)) {
7670 struct migration_req
*req
;
7672 req
= list_entry(rq
->migration_queue
.next
,
7673 struct migration_req
, list
);
7674 list_del_init(&req
->list
);
7675 spin_unlock_irq(&rq
->lock
);
7676 complete(&req
->done
);
7677 spin_lock_irq(&rq
->lock
);
7679 spin_unlock_irq(&rq
->lock
);
7683 case CPU_DYING_FROZEN
:
7684 /* Update our root-domain */
7686 spin_lock_irqsave(&rq
->lock
, flags
);
7688 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7691 spin_unlock_irqrestore(&rq
->lock
, flags
);
7699 * Register at high priority so that task migration (migrate_all_tasks)
7700 * happens before everything else. This has to be lower priority than
7701 * the notifier in the perf_counter subsystem, though.
7703 static struct notifier_block __cpuinitdata migration_notifier
= {
7704 .notifier_call
= migration_call
,
7708 static int __init
migration_init(void)
7710 void *cpu
= (void *)(long)smp_processor_id();
7713 /* Start one for the boot CPU: */
7714 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
7715 BUG_ON(err
== NOTIFY_BAD
);
7716 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
7717 register_cpu_notifier(&migration_notifier
);
7721 early_initcall(migration_init
);
7726 #ifdef CONFIG_SCHED_DEBUG
7728 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
7729 struct cpumask
*groupmask
)
7731 struct sched_group
*group
= sd
->groups
;
7734 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
7735 cpumask_clear(groupmask
);
7737 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
7739 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
7740 printk("does not load-balance\n");
7742 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
7747 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
7749 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
7750 printk(KERN_ERR
"ERROR: domain->span does not contain "
7753 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
7754 printk(KERN_ERR
"ERROR: domain->groups does not contain"
7758 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
7762 printk(KERN_ERR
"ERROR: group is NULL\n");
7766 if (!group
->__cpu_power
) {
7767 printk(KERN_CONT
"\n");
7768 printk(KERN_ERR
"ERROR: domain->cpu_power not "
7773 if (!cpumask_weight(sched_group_cpus(group
))) {
7774 printk(KERN_CONT
"\n");
7775 printk(KERN_ERR
"ERROR: empty group\n");
7779 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
7780 printk(KERN_CONT
"\n");
7781 printk(KERN_ERR
"ERROR: repeated CPUs\n");
7785 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
7787 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
7789 printk(KERN_CONT
" %s", str
);
7790 if (group
->__cpu_power
!= SCHED_LOAD_SCALE
) {
7791 printk(KERN_CONT
" (__cpu_power = %d)",
7792 group
->__cpu_power
);
7795 group
= group
->next
;
7796 } while (group
!= sd
->groups
);
7797 printk(KERN_CONT
"\n");
7799 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
7800 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
7803 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
7804 printk(KERN_ERR
"ERROR: parent span is not a superset "
7805 "of domain->span\n");
7809 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
7811 cpumask_var_t groupmask
;
7815 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
7819 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
7821 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
7822 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
7827 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
7834 free_cpumask_var(groupmask
);
7836 #else /* !CONFIG_SCHED_DEBUG */
7837 # define sched_domain_debug(sd, cpu) do { } while (0)
7838 #endif /* CONFIG_SCHED_DEBUG */
7840 static int sd_degenerate(struct sched_domain
*sd
)
7842 if (cpumask_weight(sched_domain_span(sd
)) == 1)
7845 /* Following flags need at least 2 groups */
7846 if (sd
->flags
& (SD_LOAD_BALANCE
|
7847 SD_BALANCE_NEWIDLE
|
7851 SD_SHARE_PKG_RESOURCES
)) {
7852 if (sd
->groups
!= sd
->groups
->next
)
7856 /* Following flags don't use groups */
7857 if (sd
->flags
& (SD_WAKE_IDLE
|
7866 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
7868 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
7870 if (sd_degenerate(parent
))
7873 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
7876 /* Does parent contain flags not in child? */
7877 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7878 if (cflags
& SD_WAKE_AFFINE
)
7879 pflags
&= ~SD_WAKE_BALANCE
;
7880 /* Flags needing groups don't count if only 1 group in parent */
7881 if (parent
->groups
== parent
->groups
->next
) {
7882 pflags
&= ~(SD_LOAD_BALANCE
|
7883 SD_BALANCE_NEWIDLE
|
7887 SD_SHARE_PKG_RESOURCES
);
7888 if (nr_node_ids
== 1)
7889 pflags
&= ~SD_SERIALIZE
;
7891 if (~cflags
& pflags
)
7897 static void free_rootdomain(struct root_domain
*rd
)
7899 cpupri_cleanup(&rd
->cpupri
);
7901 free_cpumask_var(rd
->rto_mask
);
7902 free_cpumask_var(rd
->online
);
7903 free_cpumask_var(rd
->span
);
7907 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7909 struct root_domain
*old_rd
= NULL
;
7910 unsigned long flags
;
7912 spin_lock_irqsave(&rq
->lock
, flags
);
7917 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
7920 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
7923 * If we dont want to free the old_rt yet then
7924 * set old_rd to NULL to skip the freeing later
7927 if (!atomic_dec_and_test(&old_rd
->refcount
))
7931 atomic_inc(&rd
->refcount
);
7934 cpumask_set_cpu(rq
->cpu
, rd
->span
);
7935 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
7938 spin_unlock_irqrestore(&rq
->lock
, flags
);
7941 free_rootdomain(old_rd
);
7944 static int init_rootdomain(struct root_domain
*rd
, bool bootmem
)
7946 gfp_t gfp
= GFP_KERNEL
;
7948 memset(rd
, 0, sizeof(*rd
));
7953 if (!alloc_cpumask_var(&rd
->span
, gfp
))
7955 if (!alloc_cpumask_var(&rd
->online
, gfp
))
7957 if (!alloc_cpumask_var(&rd
->rto_mask
, gfp
))
7960 if (cpupri_init(&rd
->cpupri
, bootmem
) != 0)
7965 free_cpumask_var(rd
->rto_mask
);
7967 free_cpumask_var(rd
->online
);
7969 free_cpumask_var(rd
->span
);
7974 static void init_defrootdomain(void)
7976 init_rootdomain(&def_root_domain
, true);
7978 atomic_set(&def_root_domain
.refcount
, 1);
7981 static struct root_domain
*alloc_rootdomain(void)
7983 struct root_domain
*rd
;
7985 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
7989 if (init_rootdomain(rd
, false) != 0) {
7998 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7999 * hold the hotplug lock.
8002 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
8004 struct rq
*rq
= cpu_rq(cpu
);
8005 struct sched_domain
*tmp
;
8007 /* Remove the sched domains which do not contribute to scheduling. */
8008 for (tmp
= sd
; tmp
; ) {
8009 struct sched_domain
*parent
= tmp
->parent
;
8013 if (sd_parent_degenerate(tmp
, parent
)) {
8014 tmp
->parent
= parent
->parent
;
8016 parent
->parent
->child
= tmp
;
8021 if (sd
&& sd_degenerate(sd
)) {
8027 sched_domain_debug(sd
, cpu
);
8029 rq_attach_root(rq
, rd
);
8030 rcu_assign_pointer(rq
->sd
, sd
);
8033 /* cpus with isolated domains */
8034 static cpumask_var_t cpu_isolated_map
;
8036 /* Setup the mask of cpus configured for isolated domains */
8037 static int __init
isolated_cpu_setup(char *str
)
8039 cpulist_parse(str
, cpu_isolated_map
);
8043 __setup("isolcpus=", isolated_cpu_setup
);
8046 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
8047 * to a function which identifies what group(along with sched group) a CPU
8048 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
8049 * (due to the fact that we keep track of groups covered with a struct cpumask).
8051 * init_sched_build_groups will build a circular linked list of the groups
8052 * covered by the given span, and will set each group's ->cpumask correctly,
8053 * and ->cpu_power to 0.
8056 init_sched_build_groups(const struct cpumask
*span
,
8057 const struct cpumask
*cpu_map
,
8058 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
8059 struct sched_group
**sg
,
8060 struct cpumask
*tmpmask
),
8061 struct cpumask
*covered
, struct cpumask
*tmpmask
)
8063 struct sched_group
*first
= NULL
, *last
= NULL
;
8066 cpumask_clear(covered
);
8068 for_each_cpu(i
, span
) {
8069 struct sched_group
*sg
;
8070 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
8073 if (cpumask_test_cpu(i
, covered
))
8076 cpumask_clear(sched_group_cpus(sg
));
8077 sg
->__cpu_power
= 0;
8079 for_each_cpu(j
, span
) {
8080 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
8083 cpumask_set_cpu(j
, covered
);
8084 cpumask_set_cpu(j
, sched_group_cpus(sg
));
8095 #define SD_NODES_PER_DOMAIN 16
8100 * find_next_best_node - find the next node to include in a sched_domain
8101 * @node: node whose sched_domain we're building
8102 * @used_nodes: nodes already in the sched_domain
8104 * Find the next node to include in a given scheduling domain. Simply
8105 * finds the closest node not already in the @used_nodes map.
8107 * Should use nodemask_t.
8109 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
8111 int i
, n
, val
, min_val
, best_node
= 0;
8115 for (i
= 0; i
< nr_node_ids
; i
++) {
8116 /* Start at @node */
8117 n
= (node
+ i
) % nr_node_ids
;
8119 if (!nr_cpus_node(n
))
8122 /* Skip already used nodes */
8123 if (node_isset(n
, *used_nodes
))
8126 /* Simple min distance search */
8127 val
= node_distance(node
, n
);
8129 if (val
< min_val
) {
8135 node_set(best_node
, *used_nodes
);
8140 * sched_domain_node_span - get a cpumask for a node's sched_domain
8141 * @node: node whose cpumask we're constructing
8142 * @span: resulting cpumask
8144 * Given a node, construct a good cpumask for its sched_domain to span. It
8145 * should be one that prevents unnecessary balancing, but also spreads tasks
8148 static void sched_domain_node_span(int node
, struct cpumask
*span
)
8150 nodemask_t used_nodes
;
8153 cpumask_clear(span
);
8154 nodes_clear(used_nodes
);
8156 cpumask_or(span
, span
, cpumask_of_node(node
));
8157 node_set(node
, used_nodes
);
8159 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
8160 int next_node
= find_next_best_node(node
, &used_nodes
);
8162 cpumask_or(span
, span
, cpumask_of_node(next_node
));
8165 #endif /* CONFIG_NUMA */
8167 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
8170 * The cpus mask in sched_group and sched_domain hangs off the end.
8172 * ( See the the comments in include/linux/sched.h:struct sched_group
8173 * and struct sched_domain. )
8175 struct static_sched_group
{
8176 struct sched_group sg
;
8177 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
8180 struct static_sched_domain
{
8181 struct sched_domain sd
;
8182 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
8186 * SMT sched-domains:
8188 #ifdef CONFIG_SCHED_SMT
8189 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
8190 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_cpus
);
8193 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
8194 struct sched_group
**sg
, struct cpumask
*unused
)
8197 *sg
= &per_cpu(sched_group_cpus
, cpu
).sg
;
8200 #endif /* CONFIG_SCHED_SMT */
8203 * multi-core sched-domains:
8205 #ifdef CONFIG_SCHED_MC
8206 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
8207 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
8208 #endif /* CONFIG_SCHED_MC */
8210 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
8212 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8213 struct sched_group
**sg
, struct cpumask
*mask
)
8217 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8218 group
= cpumask_first(mask
);
8220 *sg
= &per_cpu(sched_group_core
, group
).sg
;
8223 #elif defined(CONFIG_SCHED_MC)
8225 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8226 struct sched_group
**sg
, struct cpumask
*unused
)
8229 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
8234 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
8235 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
8238 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
8239 struct sched_group
**sg
, struct cpumask
*mask
)
8242 #ifdef CONFIG_SCHED_MC
8243 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
8244 group
= cpumask_first(mask
);
8245 #elif defined(CONFIG_SCHED_SMT)
8246 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8247 group
= cpumask_first(mask
);
8252 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
8258 * The init_sched_build_groups can't handle what we want to do with node
8259 * groups, so roll our own. Now each node has its own list of groups which
8260 * gets dynamically allocated.
8262 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
8263 static struct sched_group
***sched_group_nodes_bycpu
;
8265 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
8266 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
8268 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
8269 struct sched_group
**sg
,
8270 struct cpumask
*nodemask
)
8274 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
8275 group
= cpumask_first(nodemask
);
8278 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
8282 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
8284 struct sched_group
*sg
= group_head
;
8290 for_each_cpu(j
, sched_group_cpus(sg
)) {
8291 struct sched_domain
*sd
;
8293 sd
= &per_cpu(phys_domains
, j
).sd
;
8294 if (j
!= group_first_cpu(sd
->groups
)) {
8296 * Only add "power" once for each
8302 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
8305 } while (sg
!= group_head
);
8307 #endif /* CONFIG_NUMA */
8310 /* Free memory allocated for various sched_group structures */
8311 static void free_sched_groups(const struct cpumask
*cpu_map
,
8312 struct cpumask
*nodemask
)
8316 for_each_cpu(cpu
, cpu_map
) {
8317 struct sched_group
**sched_group_nodes
8318 = sched_group_nodes_bycpu
[cpu
];
8320 if (!sched_group_nodes
)
8323 for (i
= 0; i
< nr_node_ids
; i
++) {
8324 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
8326 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8327 if (cpumask_empty(nodemask
))
8337 if (oldsg
!= sched_group_nodes
[i
])
8340 kfree(sched_group_nodes
);
8341 sched_group_nodes_bycpu
[cpu
] = NULL
;
8344 #else /* !CONFIG_NUMA */
8345 static void free_sched_groups(const struct cpumask
*cpu_map
,
8346 struct cpumask
*nodemask
)
8349 #endif /* CONFIG_NUMA */
8352 * Initialize sched groups cpu_power.
8354 * cpu_power indicates the capacity of sched group, which is used while
8355 * distributing the load between different sched groups in a sched domain.
8356 * Typically cpu_power for all the groups in a sched domain will be same unless
8357 * there are asymmetries in the topology. If there are asymmetries, group
8358 * having more cpu_power will pickup more load compared to the group having
8361 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
8362 * the maximum number of tasks a group can handle in the presence of other idle
8363 * or lightly loaded groups in the same sched domain.
8365 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
8367 struct sched_domain
*child
;
8368 struct sched_group
*group
;
8370 WARN_ON(!sd
|| !sd
->groups
);
8372 if (cpu
!= group_first_cpu(sd
->groups
))
8377 sd
->groups
->__cpu_power
= 0;
8380 * For perf policy, if the groups in child domain share resources
8381 * (for example cores sharing some portions of the cache hierarchy
8382 * or SMT), then set this domain groups cpu_power such that each group
8383 * can handle only one task, when there are other idle groups in the
8384 * same sched domain.
8386 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
8388 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
8389 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
8394 * add cpu_power of each child group to this groups cpu_power
8396 group
= child
->groups
;
8398 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
8399 group
= group
->next
;
8400 } while (group
!= child
->groups
);
8404 * Initializers for schedule domains
8405 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
8408 #ifdef CONFIG_SCHED_DEBUG
8409 # define SD_INIT_NAME(sd, type) sd->name = #type
8411 # define SD_INIT_NAME(sd, type) do { } while (0)
8414 #define SD_INIT(sd, type) sd_init_##type(sd)
8416 #define SD_INIT_FUNC(type) \
8417 static noinline void sd_init_##type(struct sched_domain *sd) \
8419 memset(sd, 0, sizeof(*sd)); \
8420 *sd = SD_##type##_INIT; \
8421 sd->level = SD_LV_##type; \
8422 SD_INIT_NAME(sd, type); \
8427 SD_INIT_FUNC(ALLNODES
)
8430 #ifdef CONFIG_SCHED_SMT
8431 SD_INIT_FUNC(SIBLING
)
8433 #ifdef CONFIG_SCHED_MC
8437 static int default_relax_domain_level
= -1;
8439 static int __init
setup_relax_domain_level(char *str
)
8443 val
= simple_strtoul(str
, NULL
, 0);
8444 if (val
< SD_LV_MAX
)
8445 default_relax_domain_level
= val
;
8449 __setup("relax_domain_level=", setup_relax_domain_level
);
8451 static void set_domain_attribute(struct sched_domain
*sd
,
8452 struct sched_domain_attr
*attr
)
8456 if (!attr
|| attr
->relax_domain_level
< 0) {
8457 if (default_relax_domain_level
< 0)
8460 request
= default_relax_domain_level
;
8462 request
= attr
->relax_domain_level
;
8463 if (request
< sd
->level
) {
8464 /* turn off idle balance on this domain */
8465 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
8467 /* turn on idle balance on this domain */
8468 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
8473 * Build sched domains for a given set of cpus and attach the sched domains
8474 * to the individual cpus
8476 static int __build_sched_domains(const struct cpumask
*cpu_map
,
8477 struct sched_domain_attr
*attr
)
8479 int i
, err
= -ENOMEM
;
8480 struct root_domain
*rd
;
8481 cpumask_var_t nodemask
, this_sibling_map
, this_core_map
, send_covered
,
8484 cpumask_var_t domainspan
, covered
, notcovered
;
8485 struct sched_group
**sched_group_nodes
= NULL
;
8486 int sd_allnodes
= 0;
8488 if (!alloc_cpumask_var(&domainspan
, GFP_KERNEL
))
8490 if (!alloc_cpumask_var(&covered
, GFP_KERNEL
))
8491 goto free_domainspan
;
8492 if (!alloc_cpumask_var(¬covered
, GFP_KERNEL
))
8496 if (!alloc_cpumask_var(&nodemask
, GFP_KERNEL
))
8497 goto free_notcovered
;
8498 if (!alloc_cpumask_var(&this_sibling_map
, GFP_KERNEL
))
8500 if (!alloc_cpumask_var(&this_core_map
, GFP_KERNEL
))
8501 goto free_this_sibling_map
;
8502 if (!alloc_cpumask_var(&send_covered
, GFP_KERNEL
))
8503 goto free_this_core_map
;
8504 if (!alloc_cpumask_var(&tmpmask
, GFP_KERNEL
))
8505 goto free_send_covered
;
8509 * Allocate the per-node list of sched groups
8511 sched_group_nodes
= kcalloc(nr_node_ids
, sizeof(struct sched_group
*),
8513 if (!sched_group_nodes
) {
8514 printk(KERN_WARNING
"Can not alloc sched group node list\n");
8519 rd
= alloc_rootdomain();
8521 printk(KERN_WARNING
"Cannot alloc root domain\n");
8522 goto free_sched_groups
;
8526 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = sched_group_nodes
;
8530 * Set up domains for cpus specified by the cpu_map.
8532 for_each_cpu(i
, cpu_map
) {
8533 struct sched_domain
*sd
= NULL
, *p
;
8535 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(i
)), cpu_map
);
8538 if (cpumask_weight(cpu_map
) >
8539 SD_NODES_PER_DOMAIN
*cpumask_weight(nodemask
)) {
8540 sd
= &per_cpu(allnodes_domains
, i
).sd
;
8541 SD_INIT(sd
, ALLNODES
);
8542 set_domain_attribute(sd
, attr
);
8543 cpumask_copy(sched_domain_span(sd
), cpu_map
);
8544 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8550 sd
= &per_cpu(node_domains
, i
).sd
;
8552 set_domain_attribute(sd
, attr
);
8553 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
8557 cpumask_and(sched_domain_span(sd
),
8558 sched_domain_span(sd
), cpu_map
);
8562 sd
= &per_cpu(phys_domains
, i
).sd
;
8564 set_domain_attribute(sd
, attr
);
8565 cpumask_copy(sched_domain_span(sd
), nodemask
);
8569 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8571 #ifdef CONFIG_SCHED_MC
8573 sd
= &per_cpu(core_domains
, i
).sd
;
8575 set_domain_attribute(sd
, attr
);
8576 cpumask_and(sched_domain_span(sd
), cpu_map
,
8577 cpu_coregroup_mask(i
));
8580 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8583 #ifdef CONFIG_SCHED_SMT
8585 sd
= &per_cpu(cpu_domains
, i
).sd
;
8586 SD_INIT(sd
, SIBLING
);
8587 set_domain_attribute(sd
, attr
);
8588 cpumask_and(sched_domain_span(sd
),
8589 topology_thread_cpumask(i
), cpu_map
);
8592 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8596 #ifdef CONFIG_SCHED_SMT
8597 /* Set up CPU (sibling) groups */
8598 for_each_cpu(i
, cpu_map
) {
8599 cpumask_and(this_sibling_map
,
8600 topology_thread_cpumask(i
), cpu_map
);
8601 if (i
!= cpumask_first(this_sibling_map
))
8604 init_sched_build_groups(this_sibling_map
, cpu_map
,
8606 send_covered
, tmpmask
);
8610 #ifdef CONFIG_SCHED_MC
8611 /* Set up multi-core groups */
8612 for_each_cpu(i
, cpu_map
) {
8613 cpumask_and(this_core_map
, cpu_coregroup_mask(i
), cpu_map
);
8614 if (i
!= cpumask_first(this_core_map
))
8617 init_sched_build_groups(this_core_map
, cpu_map
,
8619 send_covered
, tmpmask
);
8623 /* Set up physical groups */
8624 for (i
= 0; i
< nr_node_ids
; i
++) {
8625 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8626 if (cpumask_empty(nodemask
))
8629 init_sched_build_groups(nodemask
, cpu_map
,
8631 send_covered
, tmpmask
);
8635 /* Set up node groups */
8637 init_sched_build_groups(cpu_map
, cpu_map
,
8638 &cpu_to_allnodes_group
,
8639 send_covered
, tmpmask
);
8642 for (i
= 0; i
< nr_node_ids
; i
++) {
8643 /* Set up node groups */
8644 struct sched_group
*sg
, *prev
;
8647 cpumask_clear(covered
);
8648 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8649 if (cpumask_empty(nodemask
)) {
8650 sched_group_nodes
[i
] = NULL
;
8654 sched_domain_node_span(i
, domainspan
);
8655 cpumask_and(domainspan
, domainspan
, cpu_map
);
8657 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8660 printk(KERN_WARNING
"Can not alloc domain group for "
8664 sched_group_nodes
[i
] = sg
;
8665 for_each_cpu(j
, nodemask
) {
8666 struct sched_domain
*sd
;
8668 sd
= &per_cpu(node_domains
, j
).sd
;
8671 sg
->__cpu_power
= 0;
8672 cpumask_copy(sched_group_cpus(sg
), nodemask
);
8674 cpumask_or(covered
, covered
, nodemask
);
8677 for (j
= 0; j
< nr_node_ids
; j
++) {
8678 int n
= (i
+ j
) % nr_node_ids
;
8680 cpumask_complement(notcovered
, covered
);
8681 cpumask_and(tmpmask
, notcovered
, cpu_map
);
8682 cpumask_and(tmpmask
, tmpmask
, domainspan
);
8683 if (cpumask_empty(tmpmask
))
8686 cpumask_and(tmpmask
, tmpmask
, cpumask_of_node(n
));
8687 if (cpumask_empty(tmpmask
))
8690 sg
= kmalloc_node(sizeof(struct sched_group
) +
8695 "Can not alloc domain group for node %d\n", j
);
8698 sg
->__cpu_power
= 0;
8699 cpumask_copy(sched_group_cpus(sg
), tmpmask
);
8700 sg
->next
= prev
->next
;
8701 cpumask_or(covered
, covered
, tmpmask
);
8708 /* Calculate CPU power for physical packages and nodes */
8709 #ifdef CONFIG_SCHED_SMT
8710 for_each_cpu(i
, cpu_map
) {
8711 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
).sd
;
8713 init_sched_groups_power(i
, sd
);
8716 #ifdef CONFIG_SCHED_MC
8717 for_each_cpu(i
, cpu_map
) {
8718 struct sched_domain
*sd
= &per_cpu(core_domains
, i
).sd
;
8720 init_sched_groups_power(i
, sd
);
8724 for_each_cpu(i
, cpu_map
) {
8725 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
).sd
;
8727 init_sched_groups_power(i
, sd
);
8731 for (i
= 0; i
< nr_node_ids
; i
++)
8732 init_numa_sched_groups_power(sched_group_nodes
[i
]);
8735 struct sched_group
*sg
;
8737 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
8739 init_numa_sched_groups_power(sg
);
8743 /* Attach the domains */
8744 for_each_cpu(i
, cpu_map
) {
8745 struct sched_domain
*sd
;
8746 #ifdef CONFIG_SCHED_SMT
8747 sd
= &per_cpu(cpu_domains
, i
).sd
;
8748 #elif defined(CONFIG_SCHED_MC)
8749 sd
= &per_cpu(core_domains
, i
).sd
;
8751 sd
= &per_cpu(phys_domains
, i
).sd
;
8753 cpu_attach_domain(sd
, rd
, i
);
8759 free_cpumask_var(tmpmask
);
8761 free_cpumask_var(send_covered
);
8763 free_cpumask_var(this_core_map
);
8764 free_this_sibling_map
:
8765 free_cpumask_var(this_sibling_map
);
8767 free_cpumask_var(nodemask
);
8770 free_cpumask_var(notcovered
);
8772 free_cpumask_var(covered
);
8774 free_cpumask_var(domainspan
);
8781 kfree(sched_group_nodes
);
8787 free_sched_groups(cpu_map
, tmpmask
);
8788 free_rootdomain(rd
);
8793 static int build_sched_domains(const struct cpumask
*cpu_map
)
8795 return __build_sched_domains(cpu_map
, NULL
);
8798 static struct cpumask
*doms_cur
; /* current sched domains */
8799 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
8800 static struct sched_domain_attr
*dattr_cur
;
8801 /* attribues of custom domains in 'doms_cur' */
8804 * Special case: If a kmalloc of a doms_cur partition (array of
8805 * cpumask) fails, then fallback to a single sched domain,
8806 * as determined by the single cpumask fallback_doms.
8808 static cpumask_var_t fallback_doms
;
8811 * arch_update_cpu_topology lets virtualized architectures update the
8812 * cpu core maps. It is supposed to return 1 if the topology changed
8813 * or 0 if it stayed the same.
8815 int __attribute__((weak
)) arch_update_cpu_topology(void)
8821 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8822 * For now this just excludes isolated cpus, but could be used to
8823 * exclude other special cases in the future.
8825 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
8829 arch_update_cpu_topology();
8831 doms_cur
= kmalloc(cpumask_size(), GFP_KERNEL
);
8833 doms_cur
= fallback_doms
;
8834 cpumask_andnot(doms_cur
, cpu_map
, cpu_isolated_map
);
8836 err
= build_sched_domains(doms_cur
);
8837 register_sched_domain_sysctl();
8842 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
8843 struct cpumask
*tmpmask
)
8845 free_sched_groups(cpu_map
, tmpmask
);
8849 * Detach sched domains from a group of cpus specified in cpu_map
8850 * These cpus will now be attached to the NULL domain
8852 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
8854 /* Save because hotplug lock held. */
8855 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
8858 for_each_cpu(i
, cpu_map
)
8859 cpu_attach_domain(NULL
, &def_root_domain
, i
);
8860 synchronize_sched();
8861 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
8864 /* handle null as "default" */
8865 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
8866 struct sched_domain_attr
*new, int idx_new
)
8868 struct sched_domain_attr tmp
;
8875 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
8876 new ? (new + idx_new
) : &tmp
,
8877 sizeof(struct sched_domain_attr
));
8881 * Partition sched domains as specified by the 'ndoms_new'
8882 * cpumasks in the array doms_new[] of cpumasks. This compares
8883 * doms_new[] to the current sched domain partitioning, doms_cur[].
8884 * It destroys each deleted domain and builds each new domain.
8886 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8887 * The masks don't intersect (don't overlap.) We should setup one
8888 * sched domain for each mask. CPUs not in any of the cpumasks will
8889 * not be load balanced. If the same cpumask appears both in the
8890 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8893 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8894 * ownership of it and will kfree it when done with it. If the caller
8895 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8896 * ndoms_new == 1, and partition_sched_domains() will fallback to
8897 * the single partition 'fallback_doms', it also forces the domains
8900 * If doms_new == NULL it will be replaced with cpu_online_mask.
8901 * ndoms_new == 0 is a special case for destroying existing domains,
8902 * and it will not create the default domain.
8904 * Call with hotplug lock held
8906 /* FIXME: Change to struct cpumask *doms_new[] */
8907 void partition_sched_domains(int ndoms_new
, struct cpumask
*doms_new
,
8908 struct sched_domain_attr
*dattr_new
)
8913 mutex_lock(&sched_domains_mutex
);
8915 /* always unregister in case we don't destroy any domains */
8916 unregister_sched_domain_sysctl();
8918 /* Let architecture update cpu core mappings. */
8919 new_topology
= arch_update_cpu_topology();
8921 n
= doms_new
? ndoms_new
: 0;
8923 /* Destroy deleted domains */
8924 for (i
= 0; i
< ndoms_cur
; i
++) {
8925 for (j
= 0; j
< n
&& !new_topology
; j
++) {
8926 if (cpumask_equal(&doms_cur
[i
], &doms_new
[j
])
8927 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
8930 /* no match - a current sched domain not in new doms_new[] */
8931 detach_destroy_domains(doms_cur
+ i
);
8936 if (doms_new
== NULL
) {
8938 doms_new
= fallback_doms
;
8939 cpumask_andnot(&doms_new
[0], cpu_online_mask
, cpu_isolated_map
);
8940 WARN_ON_ONCE(dattr_new
);
8943 /* Build new domains */
8944 for (i
= 0; i
< ndoms_new
; i
++) {
8945 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
8946 if (cpumask_equal(&doms_new
[i
], &doms_cur
[j
])
8947 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
8950 /* no match - add a new doms_new */
8951 __build_sched_domains(doms_new
+ i
,
8952 dattr_new
? dattr_new
+ i
: NULL
);
8957 /* Remember the new sched domains */
8958 if (doms_cur
!= fallback_doms
)
8960 kfree(dattr_cur
); /* kfree(NULL) is safe */
8961 doms_cur
= doms_new
;
8962 dattr_cur
= dattr_new
;
8963 ndoms_cur
= ndoms_new
;
8965 register_sched_domain_sysctl();
8967 mutex_unlock(&sched_domains_mutex
);
8970 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8971 static void arch_reinit_sched_domains(void)
8975 /* Destroy domains first to force the rebuild */
8976 partition_sched_domains(0, NULL
, NULL
);
8978 rebuild_sched_domains();
8982 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
8984 unsigned int level
= 0;
8986 if (sscanf(buf
, "%u", &level
) != 1)
8990 * level is always be positive so don't check for
8991 * level < POWERSAVINGS_BALANCE_NONE which is 0
8992 * What happens on 0 or 1 byte write,
8993 * need to check for count as well?
8996 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
9000 sched_smt_power_savings
= level
;
9002 sched_mc_power_savings
= level
;
9004 arch_reinit_sched_domains();
9009 #ifdef CONFIG_SCHED_MC
9010 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
9013 return sprintf(page
, "%u\n", sched_mc_power_savings
);
9015 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
9016 const char *buf
, size_t count
)
9018 return sched_power_savings_store(buf
, count
, 0);
9020 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
9021 sched_mc_power_savings_show
,
9022 sched_mc_power_savings_store
);
9025 #ifdef CONFIG_SCHED_SMT
9026 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
9029 return sprintf(page
, "%u\n", sched_smt_power_savings
);
9031 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
9032 const char *buf
, size_t count
)
9034 return sched_power_savings_store(buf
, count
, 1);
9036 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
9037 sched_smt_power_savings_show
,
9038 sched_smt_power_savings_store
);
9041 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
9045 #ifdef CONFIG_SCHED_SMT
9047 err
= sysfs_create_file(&cls
->kset
.kobj
,
9048 &attr_sched_smt_power_savings
.attr
);
9050 #ifdef CONFIG_SCHED_MC
9051 if (!err
&& mc_capable())
9052 err
= sysfs_create_file(&cls
->kset
.kobj
,
9053 &attr_sched_mc_power_savings
.attr
);
9057 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
9059 #ifndef CONFIG_CPUSETS
9061 * Add online and remove offline CPUs from the scheduler domains.
9062 * When cpusets are enabled they take over this function.
9064 static int update_sched_domains(struct notifier_block
*nfb
,
9065 unsigned long action
, void *hcpu
)
9069 case CPU_ONLINE_FROZEN
:
9071 case CPU_DEAD_FROZEN
:
9072 partition_sched_domains(1, NULL
, NULL
);
9081 static int update_runtime(struct notifier_block
*nfb
,
9082 unsigned long action
, void *hcpu
)
9084 int cpu
= (int)(long)hcpu
;
9087 case CPU_DOWN_PREPARE
:
9088 case CPU_DOWN_PREPARE_FROZEN
:
9089 disable_runtime(cpu_rq(cpu
));
9092 case CPU_DOWN_FAILED
:
9093 case CPU_DOWN_FAILED_FROZEN
:
9095 case CPU_ONLINE_FROZEN
:
9096 enable_runtime(cpu_rq(cpu
));
9104 void __init
sched_init_smp(void)
9106 cpumask_var_t non_isolated_cpus
;
9108 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
9110 #if defined(CONFIG_NUMA)
9111 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
9113 BUG_ON(sched_group_nodes_bycpu
== NULL
);
9116 mutex_lock(&sched_domains_mutex
);
9117 arch_init_sched_domains(cpu_online_mask
);
9118 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
9119 if (cpumask_empty(non_isolated_cpus
))
9120 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
9121 mutex_unlock(&sched_domains_mutex
);
9124 #ifndef CONFIG_CPUSETS
9125 /* XXX: Theoretical race here - CPU may be hotplugged now */
9126 hotcpu_notifier(update_sched_domains
, 0);
9129 /* RT runtime code needs to handle some hotplug events */
9130 hotcpu_notifier(update_runtime
, 0);
9134 /* Move init over to a non-isolated CPU */
9135 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
9137 sched_init_granularity();
9138 free_cpumask_var(non_isolated_cpus
);
9140 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
9141 init_sched_rt_class();
9144 void __init
sched_init_smp(void)
9146 sched_init_granularity();
9148 #endif /* CONFIG_SMP */
9150 const_debug
unsigned int sysctl_timer_migration
= 1;
9152 int in_sched_functions(unsigned long addr
)
9154 return in_lock_functions(addr
) ||
9155 (addr
>= (unsigned long)__sched_text_start
9156 && addr
< (unsigned long)__sched_text_end
);
9159 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
9161 cfs_rq
->tasks_timeline
= RB_ROOT
;
9162 INIT_LIST_HEAD(&cfs_rq
->tasks
);
9163 #ifdef CONFIG_FAIR_GROUP_SCHED
9166 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
9169 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
9171 struct rt_prio_array
*array
;
9174 array
= &rt_rq
->active
;
9175 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
9176 INIT_LIST_HEAD(array
->queue
+ i
);
9177 __clear_bit(i
, array
->bitmap
);
9179 /* delimiter for bitsearch: */
9180 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
9182 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
9183 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
9185 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
9189 rt_rq
->rt_nr_migratory
= 0;
9190 rt_rq
->overloaded
= 0;
9191 plist_head_init(&rt_rq
->pushable_tasks
, &rq
->lock
);
9195 rt_rq
->rt_throttled
= 0;
9196 rt_rq
->rt_runtime
= 0;
9197 spin_lock_init(&rt_rq
->rt_runtime_lock
);
9199 #ifdef CONFIG_RT_GROUP_SCHED
9200 rt_rq
->rt_nr_boosted
= 0;
9205 #ifdef CONFIG_FAIR_GROUP_SCHED
9206 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
9207 struct sched_entity
*se
, int cpu
, int add
,
9208 struct sched_entity
*parent
)
9210 struct rq
*rq
= cpu_rq(cpu
);
9211 tg
->cfs_rq
[cpu
] = cfs_rq
;
9212 init_cfs_rq(cfs_rq
, rq
);
9215 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
9218 /* se could be NULL for init_task_group */
9223 se
->cfs_rq
= &rq
->cfs
;
9225 se
->cfs_rq
= parent
->my_q
;
9228 se
->load
.weight
= tg
->shares
;
9229 se
->load
.inv_weight
= 0;
9230 se
->parent
= parent
;
9234 #ifdef CONFIG_RT_GROUP_SCHED
9235 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
9236 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
9237 struct sched_rt_entity
*parent
)
9239 struct rq
*rq
= cpu_rq(cpu
);
9241 tg
->rt_rq
[cpu
] = rt_rq
;
9242 init_rt_rq(rt_rq
, rq
);
9244 rt_rq
->rt_se
= rt_se
;
9245 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9247 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
9249 tg
->rt_se
[cpu
] = rt_se
;
9254 rt_se
->rt_rq
= &rq
->rt
;
9256 rt_se
->rt_rq
= parent
->my_q
;
9258 rt_se
->my_q
= rt_rq
;
9259 rt_se
->parent
= parent
;
9260 INIT_LIST_HEAD(&rt_se
->run_list
);
9264 void __init
sched_init(void)
9267 unsigned long alloc_size
= 0, ptr
;
9269 #ifdef CONFIG_FAIR_GROUP_SCHED
9270 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9272 #ifdef CONFIG_RT_GROUP_SCHED
9273 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9275 #ifdef CONFIG_USER_SCHED
9278 #ifdef CONFIG_CPUMASK_OFFSTACK
9279 alloc_size
+= num_possible_cpus() * cpumask_size();
9282 * As sched_init() is called before page_alloc is setup,
9283 * we use alloc_bootmem().
9286 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
9288 #ifdef CONFIG_FAIR_GROUP_SCHED
9289 init_task_group
.se
= (struct sched_entity
**)ptr
;
9290 ptr
+= nr_cpu_ids
* sizeof(void **);
9292 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9293 ptr
+= nr_cpu_ids
* sizeof(void **);
9295 #ifdef CONFIG_USER_SCHED
9296 root_task_group
.se
= (struct sched_entity
**)ptr
;
9297 ptr
+= nr_cpu_ids
* sizeof(void **);
9299 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9300 ptr
+= nr_cpu_ids
* sizeof(void **);
9301 #endif /* CONFIG_USER_SCHED */
9302 #endif /* CONFIG_FAIR_GROUP_SCHED */
9303 #ifdef CONFIG_RT_GROUP_SCHED
9304 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9305 ptr
+= nr_cpu_ids
* sizeof(void **);
9307 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9308 ptr
+= nr_cpu_ids
* sizeof(void **);
9310 #ifdef CONFIG_USER_SCHED
9311 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9312 ptr
+= nr_cpu_ids
* sizeof(void **);
9314 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9315 ptr
+= nr_cpu_ids
* sizeof(void **);
9316 #endif /* CONFIG_USER_SCHED */
9317 #endif /* CONFIG_RT_GROUP_SCHED */
9318 #ifdef CONFIG_CPUMASK_OFFSTACK
9319 for_each_possible_cpu(i
) {
9320 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
9321 ptr
+= cpumask_size();
9323 #endif /* CONFIG_CPUMASK_OFFSTACK */
9327 init_defrootdomain();
9330 init_rt_bandwidth(&def_rt_bandwidth
,
9331 global_rt_period(), global_rt_runtime());
9333 #ifdef CONFIG_RT_GROUP_SCHED
9334 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
9335 global_rt_period(), global_rt_runtime());
9336 #ifdef CONFIG_USER_SCHED
9337 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
9338 global_rt_period(), RUNTIME_INF
);
9339 #endif /* CONFIG_USER_SCHED */
9340 #endif /* CONFIG_RT_GROUP_SCHED */
9342 #ifdef CONFIG_GROUP_SCHED
9343 list_add(&init_task_group
.list
, &task_groups
);
9344 INIT_LIST_HEAD(&init_task_group
.children
);
9346 #ifdef CONFIG_USER_SCHED
9347 INIT_LIST_HEAD(&root_task_group
.children
);
9348 init_task_group
.parent
= &root_task_group
;
9349 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
9350 #endif /* CONFIG_USER_SCHED */
9351 #endif /* CONFIG_GROUP_SCHED */
9353 for_each_possible_cpu(i
) {
9357 spin_lock_init(&rq
->lock
);
9359 rq
->calc_load_active
= 0;
9360 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
9361 init_cfs_rq(&rq
->cfs
, rq
);
9362 init_rt_rq(&rq
->rt
, rq
);
9363 #ifdef CONFIG_FAIR_GROUP_SCHED
9364 init_task_group
.shares
= init_task_group_load
;
9365 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
9366 #ifdef CONFIG_CGROUP_SCHED
9368 * How much cpu bandwidth does init_task_group get?
9370 * In case of task-groups formed thr' the cgroup filesystem, it
9371 * gets 100% of the cpu resources in the system. This overall
9372 * system cpu resource is divided among the tasks of
9373 * init_task_group and its child task-groups in a fair manner,
9374 * based on each entity's (task or task-group's) weight
9375 * (se->load.weight).
9377 * In other words, if init_task_group has 10 tasks of weight
9378 * 1024) and two child groups A0 and A1 (of weight 1024 each),
9379 * then A0's share of the cpu resource is:
9381 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
9383 * We achieve this by letting init_task_group's tasks sit
9384 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
9386 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
9387 #elif defined CONFIG_USER_SCHED
9388 root_task_group
.shares
= NICE_0_LOAD
;
9389 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
9391 * In case of task-groups formed thr' the user id of tasks,
9392 * init_task_group represents tasks belonging to root user.
9393 * Hence it forms a sibling of all subsequent groups formed.
9394 * In this case, init_task_group gets only a fraction of overall
9395 * system cpu resource, based on the weight assigned to root
9396 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
9397 * by letting tasks of init_task_group sit in a separate cfs_rq
9398 * (init_cfs_rq) and having one entity represent this group of
9399 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
9401 init_tg_cfs_entry(&init_task_group
,
9402 &per_cpu(init_cfs_rq
, i
),
9403 &per_cpu(init_sched_entity
, i
), i
, 1,
9404 root_task_group
.se
[i
]);
9407 #endif /* CONFIG_FAIR_GROUP_SCHED */
9409 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
9410 #ifdef CONFIG_RT_GROUP_SCHED
9411 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
9412 #ifdef CONFIG_CGROUP_SCHED
9413 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
9414 #elif defined CONFIG_USER_SCHED
9415 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
9416 init_tg_rt_entry(&init_task_group
,
9417 &per_cpu(init_rt_rq
, i
),
9418 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
9419 root_task_group
.rt_se
[i
]);
9423 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
9424 rq
->cpu_load
[j
] = 0;
9428 rq
->post_schedule
= 0;
9429 rq
->active_balance
= 0;
9430 rq
->next_balance
= jiffies
;
9434 rq
->migration_thread
= NULL
;
9435 INIT_LIST_HEAD(&rq
->migration_queue
);
9436 rq_attach_root(rq
, &def_root_domain
);
9439 atomic_set(&rq
->nr_iowait
, 0);
9442 set_load_weight(&init_task
);
9444 #ifdef CONFIG_PREEMPT_NOTIFIERS
9445 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
9449 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
9452 #ifdef CONFIG_RT_MUTEXES
9453 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
9457 * The boot idle thread does lazy MMU switching as well:
9459 atomic_inc(&init_mm
.mm_count
);
9460 enter_lazy_tlb(&init_mm
, current
);
9463 * Make us the idle thread. Technically, schedule() should not be
9464 * called from this thread, however somewhere below it might be,
9465 * but because we are the idle thread, we just pick up running again
9466 * when this runqueue becomes "idle".
9468 init_idle(current
, smp_processor_id());
9470 calc_load_update
= jiffies
+ LOAD_FREQ
;
9473 * During early bootup we pretend to be a normal task:
9475 current
->sched_class
= &fair_sched_class
;
9477 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9478 alloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
9481 alloc_cpumask_var(&nohz
.cpu_mask
, GFP_NOWAIT
);
9482 alloc_cpumask_var(&nohz
.ilb_grp_nohz_mask
, GFP_NOWAIT
);
9484 alloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
9487 perf_counter_init();
9489 scheduler_running
= 1;
9492 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9493 static inline int preempt_count_equals(int preempt_offset
)
9495 int nested
= preempt_count() & ~PREEMPT_ACTIVE
;
9497 return (nested
== PREEMPT_INATOMIC_BASE
+ preempt_offset
);
9500 void __might_sleep(char *file
, int line
, int preempt_offset
)
9503 static unsigned long prev_jiffy
; /* ratelimiting */
9505 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
9506 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
9508 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
9510 prev_jiffy
= jiffies
;
9513 "BUG: sleeping function called from invalid context at %s:%d\n",
9516 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9517 in_atomic(), irqs_disabled(),
9518 current
->pid
, current
->comm
);
9520 debug_show_held_locks(current
);
9521 if (irqs_disabled())
9522 print_irqtrace_events(current
);
9526 EXPORT_SYMBOL(__might_sleep
);
9529 #ifdef CONFIG_MAGIC_SYSRQ
9530 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
9534 update_rq_clock(rq
);
9535 on_rq
= p
->se
.on_rq
;
9537 deactivate_task(rq
, p
, 0);
9538 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
9540 activate_task(rq
, p
, 0);
9541 resched_task(rq
->curr
);
9545 void normalize_rt_tasks(void)
9547 struct task_struct
*g
, *p
;
9548 unsigned long flags
;
9551 read_lock_irqsave(&tasklist_lock
, flags
);
9552 do_each_thread(g
, p
) {
9554 * Only normalize user tasks:
9559 p
->se
.exec_start
= 0;
9560 #ifdef CONFIG_SCHEDSTATS
9561 p
->se
.wait_start
= 0;
9562 p
->se
.sleep_start
= 0;
9563 p
->se
.block_start
= 0;
9568 * Renice negative nice level userspace
9571 if (TASK_NICE(p
) < 0 && p
->mm
)
9572 set_user_nice(p
, 0);
9576 spin_lock(&p
->pi_lock
);
9577 rq
= __task_rq_lock(p
);
9579 normalize_task(rq
, p
);
9581 __task_rq_unlock(rq
);
9582 spin_unlock(&p
->pi_lock
);
9583 } while_each_thread(g
, p
);
9585 read_unlock_irqrestore(&tasklist_lock
, flags
);
9588 #endif /* CONFIG_MAGIC_SYSRQ */
9592 * These functions are only useful for the IA64 MCA handling.
9594 * They can only be called when the whole system has been
9595 * stopped - every CPU needs to be quiescent, and no scheduling
9596 * activity can take place. Using them for anything else would
9597 * be a serious bug, and as a result, they aren't even visible
9598 * under any other configuration.
9602 * curr_task - return the current task for a given cpu.
9603 * @cpu: the processor in question.
9605 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9607 struct task_struct
*curr_task(int cpu
)
9609 return cpu_curr(cpu
);
9613 * set_curr_task - set the current task for a given cpu.
9614 * @cpu: the processor in question.
9615 * @p: the task pointer to set.
9617 * Description: This function must only be used when non-maskable interrupts
9618 * are serviced on a separate stack. It allows the architecture to switch the
9619 * notion of the current task on a cpu in a non-blocking manner. This function
9620 * must be called with all CPU's synchronized, and interrupts disabled, the
9621 * and caller must save the original value of the current task (see
9622 * curr_task() above) and restore that value before reenabling interrupts and
9623 * re-starting the system.
9625 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9627 void set_curr_task(int cpu
, struct task_struct
*p
)
9634 #ifdef CONFIG_FAIR_GROUP_SCHED
9635 static void free_fair_sched_group(struct task_group
*tg
)
9639 for_each_possible_cpu(i
) {
9641 kfree(tg
->cfs_rq
[i
]);
9651 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9653 struct cfs_rq
*cfs_rq
;
9654 struct sched_entity
*se
;
9658 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9661 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
9665 tg
->shares
= NICE_0_LOAD
;
9667 for_each_possible_cpu(i
) {
9670 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
9671 GFP_KERNEL
, cpu_to_node(i
));
9675 se
= kzalloc_node(sizeof(struct sched_entity
),
9676 GFP_KERNEL
, cpu_to_node(i
));
9680 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
9689 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9691 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
9692 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
9695 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9697 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
9699 #else /* !CONFG_FAIR_GROUP_SCHED */
9700 static inline void free_fair_sched_group(struct task_group
*tg
)
9705 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9710 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9714 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9717 #endif /* CONFIG_FAIR_GROUP_SCHED */
9719 #ifdef CONFIG_RT_GROUP_SCHED
9720 static void free_rt_sched_group(struct task_group
*tg
)
9724 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
9726 for_each_possible_cpu(i
) {
9728 kfree(tg
->rt_rq
[i
]);
9730 kfree(tg
->rt_se
[i
]);
9738 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9740 struct rt_rq
*rt_rq
;
9741 struct sched_rt_entity
*rt_se
;
9745 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9748 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
9752 init_rt_bandwidth(&tg
->rt_bandwidth
,
9753 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
9755 for_each_possible_cpu(i
) {
9758 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
9759 GFP_KERNEL
, cpu_to_node(i
));
9763 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
9764 GFP_KERNEL
, cpu_to_node(i
));
9768 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
9777 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9779 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
9780 &cpu_rq(cpu
)->leaf_rt_rq_list
);
9783 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9785 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
9787 #else /* !CONFIG_RT_GROUP_SCHED */
9788 static inline void free_rt_sched_group(struct task_group
*tg
)
9793 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9798 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9802 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9805 #endif /* CONFIG_RT_GROUP_SCHED */
9807 #ifdef CONFIG_GROUP_SCHED
9808 static void free_sched_group(struct task_group
*tg
)
9810 free_fair_sched_group(tg
);
9811 free_rt_sched_group(tg
);
9815 /* allocate runqueue etc for a new task group */
9816 struct task_group
*sched_create_group(struct task_group
*parent
)
9818 struct task_group
*tg
;
9819 unsigned long flags
;
9822 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
9824 return ERR_PTR(-ENOMEM
);
9826 if (!alloc_fair_sched_group(tg
, parent
))
9829 if (!alloc_rt_sched_group(tg
, parent
))
9832 spin_lock_irqsave(&task_group_lock
, flags
);
9833 for_each_possible_cpu(i
) {
9834 register_fair_sched_group(tg
, i
);
9835 register_rt_sched_group(tg
, i
);
9837 list_add_rcu(&tg
->list
, &task_groups
);
9839 WARN_ON(!parent
); /* root should already exist */
9841 tg
->parent
= parent
;
9842 INIT_LIST_HEAD(&tg
->children
);
9843 list_add_rcu(&tg
->siblings
, &parent
->children
);
9844 spin_unlock_irqrestore(&task_group_lock
, flags
);
9849 free_sched_group(tg
);
9850 return ERR_PTR(-ENOMEM
);
9853 /* rcu callback to free various structures associated with a task group */
9854 static void free_sched_group_rcu(struct rcu_head
*rhp
)
9856 /* now it should be safe to free those cfs_rqs */
9857 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
9860 /* Destroy runqueue etc associated with a task group */
9861 void sched_destroy_group(struct task_group
*tg
)
9863 unsigned long flags
;
9866 spin_lock_irqsave(&task_group_lock
, flags
);
9867 for_each_possible_cpu(i
) {
9868 unregister_fair_sched_group(tg
, i
);
9869 unregister_rt_sched_group(tg
, i
);
9871 list_del_rcu(&tg
->list
);
9872 list_del_rcu(&tg
->siblings
);
9873 spin_unlock_irqrestore(&task_group_lock
, flags
);
9875 /* wait for possible concurrent references to cfs_rqs complete */
9876 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
9879 /* change task's runqueue when it moves between groups.
9880 * The caller of this function should have put the task in its new group
9881 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
9882 * reflect its new group.
9884 void sched_move_task(struct task_struct
*tsk
)
9887 unsigned long flags
;
9890 rq
= task_rq_lock(tsk
, &flags
);
9892 update_rq_clock(rq
);
9894 running
= task_current(rq
, tsk
);
9895 on_rq
= tsk
->se
.on_rq
;
9898 dequeue_task(rq
, tsk
, 0);
9899 if (unlikely(running
))
9900 tsk
->sched_class
->put_prev_task(rq
, tsk
);
9902 set_task_rq(tsk
, task_cpu(tsk
));
9904 #ifdef CONFIG_FAIR_GROUP_SCHED
9905 if (tsk
->sched_class
->moved_group
)
9906 tsk
->sched_class
->moved_group(tsk
);
9909 if (unlikely(running
))
9910 tsk
->sched_class
->set_curr_task(rq
);
9912 enqueue_task(rq
, tsk
, 0);
9914 task_rq_unlock(rq
, &flags
);
9916 #endif /* CONFIG_GROUP_SCHED */
9918 #ifdef CONFIG_FAIR_GROUP_SCHED
9919 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9921 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9926 dequeue_entity(cfs_rq
, se
, 0);
9928 se
->load
.weight
= shares
;
9929 se
->load
.inv_weight
= 0;
9932 enqueue_entity(cfs_rq
, se
, 0);
9935 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9937 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9938 struct rq
*rq
= cfs_rq
->rq
;
9939 unsigned long flags
;
9941 spin_lock_irqsave(&rq
->lock
, flags
);
9942 __set_se_shares(se
, shares
);
9943 spin_unlock_irqrestore(&rq
->lock
, flags
);
9946 static DEFINE_MUTEX(shares_mutex
);
9948 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
9951 unsigned long flags
;
9954 * We can't change the weight of the root cgroup.
9959 if (shares
< MIN_SHARES
)
9960 shares
= MIN_SHARES
;
9961 else if (shares
> MAX_SHARES
)
9962 shares
= MAX_SHARES
;
9964 mutex_lock(&shares_mutex
);
9965 if (tg
->shares
== shares
)
9968 spin_lock_irqsave(&task_group_lock
, flags
);
9969 for_each_possible_cpu(i
)
9970 unregister_fair_sched_group(tg
, i
);
9971 list_del_rcu(&tg
->siblings
);
9972 spin_unlock_irqrestore(&task_group_lock
, flags
);
9974 /* wait for any ongoing reference to this group to finish */
9975 synchronize_sched();
9978 * Now we are free to modify the group's share on each cpu
9979 * w/o tripping rebalance_share or load_balance_fair.
9981 tg
->shares
= shares
;
9982 for_each_possible_cpu(i
) {
9986 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
9987 set_se_shares(tg
->se
[i
], shares
);
9991 * Enable load balance activity on this group, by inserting it back on
9992 * each cpu's rq->leaf_cfs_rq_list.
9994 spin_lock_irqsave(&task_group_lock
, flags
);
9995 for_each_possible_cpu(i
)
9996 register_fair_sched_group(tg
, i
);
9997 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
9998 spin_unlock_irqrestore(&task_group_lock
, flags
);
10000 mutex_unlock(&shares_mutex
);
10004 unsigned long sched_group_shares(struct task_group
*tg
)
10010 #ifdef CONFIG_RT_GROUP_SCHED
10012 * Ensure that the real time constraints are schedulable.
10014 static DEFINE_MUTEX(rt_constraints_mutex
);
10016 static unsigned long to_ratio(u64 period
, u64 runtime
)
10018 if (runtime
== RUNTIME_INF
)
10021 return div64_u64(runtime
<< 20, period
);
10024 /* Must be called with tasklist_lock held */
10025 static inline int tg_has_rt_tasks(struct task_group
*tg
)
10027 struct task_struct
*g
, *p
;
10029 do_each_thread(g
, p
) {
10030 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
10032 } while_each_thread(g
, p
);
10037 struct rt_schedulable_data
{
10038 struct task_group
*tg
;
10043 static int tg_schedulable(struct task_group
*tg
, void *data
)
10045 struct rt_schedulable_data
*d
= data
;
10046 struct task_group
*child
;
10047 unsigned long total
, sum
= 0;
10048 u64 period
, runtime
;
10050 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10051 runtime
= tg
->rt_bandwidth
.rt_runtime
;
10054 period
= d
->rt_period
;
10055 runtime
= d
->rt_runtime
;
10058 #ifdef CONFIG_USER_SCHED
10059 if (tg
== &root_task_group
) {
10060 period
= global_rt_period();
10061 runtime
= global_rt_runtime();
10066 * Cannot have more runtime than the period.
10068 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10072 * Ensure we don't starve existing RT tasks.
10074 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
10077 total
= to_ratio(period
, runtime
);
10080 * Nobody can have more than the global setting allows.
10082 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
10086 * The sum of our children's runtime should not exceed our own.
10088 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
10089 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
10090 runtime
= child
->rt_bandwidth
.rt_runtime
;
10092 if (child
== d
->tg
) {
10093 period
= d
->rt_period
;
10094 runtime
= d
->rt_runtime
;
10097 sum
+= to_ratio(period
, runtime
);
10106 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
10108 struct rt_schedulable_data data
= {
10110 .rt_period
= period
,
10111 .rt_runtime
= runtime
,
10114 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
10117 static int tg_set_bandwidth(struct task_group
*tg
,
10118 u64 rt_period
, u64 rt_runtime
)
10122 mutex_lock(&rt_constraints_mutex
);
10123 read_lock(&tasklist_lock
);
10124 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
10128 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10129 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
10130 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
10132 for_each_possible_cpu(i
) {
10133 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
10135 spin_lock(&rt_rq
->rt_runtime_lock
);
10136 rt_rq
->rt_runtime
= rt_runtime
;
10137 spin_unlock(&rt_rq
->rt_runtime_lock
);
10139 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10141 read_unlock(&tasklist_lock
);
10142 mutex_unlock(&rt_constraints_mutex
);
10147 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
10149 u64 rt_runtime
, rt_period
;
10151 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10152 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
10153 if (rt_runtime_us
< 0)
10154 rt_runtime
= RUNTIME_INF
;
10156 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10159 long sched_group_rt_runtime(struct task_group
*tg
)
10163 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
10166 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
10167 do_div(rt_runtime_us
, NSEC_PER_USEC
);
10168 return rt_runtime_us
;
10171 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
10173 u64 rt_runtime
, rt_period
;
10175 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
10176 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
10178 if (rt_period
== 0)
10181 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10184 long sched_group_rt_period(struct task_group
*tg
)
10188 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10189 do_div(rt_period_us
, NSEC_PER_USEC
);
10190 return rt_period_us
;
10193 static int sched_rt_global_constraints(void)
10195 u64 runtime
, period
;
10198 if (sysctl_sched_rt_period
<= 0)
10201 runtime
= global_rt_runtime();
10202 period
= global_rt_period();
10205 * Sanity check on the sysctl variables.
10207 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10210 mutex_lock(&rt_constraints_mutex
);
10211 read_lock(&tasklist_lock
);
10212 ret
= __rt_schedulable(NULL
, 0, 0);
10213 read_unlock(&tasklist_lock
);
10214 mutex_unlock(&rt_constraints_mutex
);
10219 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
10221 /* Don't accept realtime tasks when there is no way for them to run */
10222 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
10228 #else /* !CONFIG_RT_GROUP_SCHED */
10229 static int sched_rt_global_constraints(void)
10231 unsigned long flags
;
10234 if (sysctl_sched_rt_period
<= 0)
10238 * There's always some RT tasks in the root group
10239 * -- migration, kstopmachine etc..
10241 if (sysctl_sched_rt_runtime
== 0)
10244 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10245 for_each_possible_cpu(i
) {
10246 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
10248 spin_lock(&rt_rq
->rt_runtime_lock
);
10249 rt_rq
->rt_runtime
= global_rt_runtime();
10250 spin_unlock(&rt_rq
->rt_runtime_lock
);
10252 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10256 #endif /* CONFIG_RT_GROUP_SCHED */
10258 int sched_rt_handler(struct ctl_table
*table
, int write
,
10259 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
10263 int old_period
, old_runtime
;
10264 static DEFINE_MUTEX(mutex
);
10266 mutex_lock(&mutex
);
10267 old_period
= sysctl_sched_rt_period
;
10268 old_runtime
= sysctl_sched_rt_runtime
;
10270 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
10272 if (!ret
&& write
) {
10273 ret
= sched_rt_global_constraints();
10275 sysctl_sched_rt_period
= old_period
;
10276 sysctl_sched_rt_runtime
= old_runtime
;
10278 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
10279 def_rt_bandwidth
.rt_period
=
10280 ns_to_ktime(global_rt_period());
10283 mutex_unlock(&mutex
);
10288 #ifdef CONFIG_CGROUP_SCHED
10290 /* return corresponding task_group object of a cgroup */
10291 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
10293 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
10294 struct task_group
, css
);
10297 static struct cgroup_subsys_state
*
10298 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10300 struct task_group
*tg
, *parent
;
10302 if (!cgrp
->parent
) {
10303 /* This is early initialization for the top cgroup */
10304 return &init_task_group
.css
;
10307 parent
= cgroup_tg(cgrp
->parent
);
10308 tg
= sched_create_group(parent
);
10310 return ERR_PTR(-ENOMEM
);
10316 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10318 struct task_group
*tg
= cgroup_tg(cgrp
);
10320 sched_destroy_group(tg
);
10324 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10325 struct task_struct
*tsk
)
10327 #ifdef CONFIG_RT_GROUP_SCHED
10328 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
10331 /* We don't support RT-tasks being in separate groups */
10332 if (tsk
->sched_class
!= &fair_sched_class
)
10340 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10341 struct cgroup
*old_cont
, struct task_struct
*tsk
)
10343 sched_move_task(tsk
);
10346 #ifdef CONFIG_FAIR_GROUP_SCHED
10347 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
10350 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
10353 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
10355 struct task_group
*tg
= cgroup_tg(cgrp
);
10357 return (u64
) tg
->shares
;
10359 #endif /* CONFIG_FAIR_GROUP_SCHED */
10361 #ifdef CONFIG_RT_GROUP_SCHED
10362 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
10365 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
10368 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10370 return sched_group_rt_runtime(cgroup_tg(cgrp
));
10373 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
10376 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
10379 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
10381 return sched_group_rt_period(cgroup_tg(cgrp
));
10383 #endif /* CONFIG_RT_GROUP_SCHED */
10385 static struct cftype cpu_files
[] = {
10386 #ifdef CONFIG_FAIR_GROUP_SCHED
10389 .read_u64
= cpu_shares_read_u64
,
10390 .write_u64
= cpu_shares_write_u64
,
10393 #ifdef CONFIG_RT_GROUP_SCHED
10395 .name
= "rt_runtime_us",
10396 .read_s64
= cpu_rt_runtime_read
,
10397 .write_s64
= cpu_rt_runtime_write
,
10400 .name
= "rt_period_us",
10401 .read_u64
= cpu_rt_period_read_uint
,
10402 .write_u64
= cpu_rt_period_write_uint
,
10407 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
10409 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
10412 struct cgroup_subsys cpu_cgroup_subsys
= {
10414 .create
= cpu_cgroup_create
,
10415 .destroy
= cpu_cgroup_destroy
,
10416 .can_attach
= cpu_cgroup_can_attach
,
10417 .attach
= cpu_cgroup_attach
,
10418 .populate
= cpu_cgroup_populate
,
10419 .subsys_id
= cpu_cgroup_subsys_id
,
10423 #endif /* CONFIG_CGROUP_SCHED */
10425 #ifdef CONFIG_CGROUP_CPUACCT
10428 * CPU accounting code for task groups.
10430 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
10431 * (balbir@in.ibm.com).
10434 /* track cpu usage of a group of tasks and its child groups */
10436 struct cgroup_subsys_state css
;
10437 /* cpuusage holds pointer to a u64-type object on every cpu */
10439 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
10440 struct cpuacct
*parent
;
10443 struct cgroup_subsys cpuacct_subsys
;
10445 /* return cpu accounting group corresponding to this container */
10446 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
10448 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
10449 struct cpuacct
, css
);
10452 /* return cpu accounting group to which this task belongs */
10453 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
10455 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
10456 struct cpuacct
, css
);
10459 /* create a new cpu accounting group */
10460 static struct cgroup_subsys_state
*cpuacct_create(
10461 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10463 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
10469 ca
->cpuusage
= alloc_percpu(u64
);
10473 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10474 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
10475 goto out_free_counters
;
10478 ca
->parent
= cgroup_ca(cgrp
->parent
);
10484 percpu_counter_destroy(&ca
->cpustat
[i
]);
10485 free_percpu(ca
->cpuusage
);
10489 return ERR_PTR(-ENOMEM
);
10492 /* destroy an existing cpu accounting group */
10494 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10496 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10499 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10500 percpu_counter_destroy(&ca
->cpustat
[i
]);
10501 free_percpu(ca
->cpuusage
);
10505 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
10507 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10510 #ifndef CONFIG_64BIT
10512 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10514 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10516 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10524 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
10526 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10528 #ifndef CONFIG_64BIT
10530 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10532 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10534 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10540 /* return total cpu usage (in nanoseconds) of a group */
10541 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10543 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10544 u64 totalcpuusage
= 0;
10547 for_each_present_cpu(i
)
10548 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
10550 return totalcpuusage
;
10553 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
10556 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10565 for_each_present_cpu(i
)
10566 cpuacct_cpuusage_write(ca
, i
, 0);
10572 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
10573 struct seq_file
*m
)
10575 struct cpuacct
*ca
= cgroup_ca(cgroup
);
10579 for_each_present_cpu(i
) {
10580 percpu
= cpuacct_cpuusage_read(ca
, i
);
10581 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
10583 seq_printf(m
, "\n");
10587 static const char *cpuacct_stat_desc
[] = {
10588 [CPUACCT_STAT_USER
] = "user",
10589 [CPUACCT_STAT_SYSTEM
] = "system",
10592 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
10593 struct cgroup_map_cb
*cb
)
10595 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10598 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
10599 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
10600 val
= cputime64_to_clock_t(val
);
10601 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
10606 static struct cftype files
[] = {
10609 .read_u64
= cpuusage_read
,
10610 .write_u64
= cpuusage_write
,
10613 .name
= "usage_percpu",
10614 .read_seq_string
= cpuacct_percpu_seq_read
,
10618 .read_map
= cpuacct_stats_show
,
10622 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10624 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
10628 * charge this task's execution time to its accounting group.
10630 * called with rq->lock held.
10632 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
10634 struct cpuacct
*ca
;
10637 if (unlikely(!cpuacct_subsys
.active
))
10640 cpu
= task_cpu(tsk
);
10646 for (; ca
; ca
= ca
->parent
) {
10647 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10648 *cpuusage
+= cputime
;
10655 * Charge the system/user time to the task's accounting group.
10657 static void cpuacct_update_stats(struct task_struct
*tsk
,
10658 enum cpuacct_stat_index idx
, cputime_t val
)
10660 struct cpuacct
*ca
;
10662 if (unlikely(!cpuacct_subsys
.active
))
10669 percpu_counter_add(&ca
->cpustat
[idx
], val
);
10675 struct cgroup_subsys cpuacct_subsys
= {
10677 .create
= cpuacct_create
,
10678 .destroy
= cpuacct_destroy
,
10679 .populate
= cpuacct_populate
,
10680 .subsys_id
= cpuacct_subsys_id
,
10682 #endif /* CONFIG_CGROUP_CPUACCT */