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
;
497 struct plist_head pushable_tasks
;
502 /* Nests inside the rq lock: */
503 spinlock_t rt_runtime_lock
;
505 #ifdef CONFIG_RT_GROUP_SCHED
506 unsigned long rt_nr_boosted
;
509 struct list_head leaf_rt_rq_list
;
510 struct task_group
*tg
;
511 struct sched_rt_entity
*rt_se
;
518 * We add the notion of a root-domain which will be used to define per-domain
519 * variables. Each exclusive cpuset essentially defines an island domain by
520 * fully partitioning the member cpus from any other cpuset. Whenever a new
521 * exclusive cpuset is created, we also create and attach a new root-domain
528 cpumask_var_t online
;
531 * The "RT overload" flag: it gets set if a CPU has more than
532 * one runnable RT task.
534 cpumask_var_t rto_mask
;
537 struct cpupri cpupri
;
539 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
541 * Preferred wake up cpu nominated by sched_mc balance that will be
542 * used when most cpus are idle in the system indicating overall very
543 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
545 unsigned int sched_mc_preferred_wakeup_cpu
;
550 * By default the system creates a single root-domain with all cpus as
551 * members (mimicking the global state we have today).
553 static struct root_domain def_root_domain
;
558 * This is the main, per-CPU runqueue data structure.
560 * Locking rule: those places that want to lock multiple runqueues
561 * (such as the load balancing or the thread migration code), lock
562 * acquire operations must be ordered by ascending &runqueue.
569 * nr_running and cpu_load should be in the same cacheline because
570 * remote CPUs use both these fields when doing load calculation.
572 unsigned long nr_running
;
573 #define CPU_LOAD_IDX_MAX 5
574 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
576 unsigned long last_tick_seen
;
577 unsigned char in_nohz_recently
;
579 /* capture load from *all* tasks on this cpu: */
580 struct load_weight load
;
581 unsigned long nr_load_updates
;
583 u64 nr_migrations_in
;
588 #ifdef CONFIG_FAIR_GROUP_SCHED
589 /* list of leaf cfs_rq on this cpu: */
590 struct list_head leaf_cfs_rq_list
;
592 #ifdef CONFIG_RT_GROUP_SCHED
593 struct list_head leaf_rt_rq_list
;
597 * This is part of a global counter where only the total sum
598 * over all CPUs matters. A task can increase this counter on
599 * one CPU and if it got migrated afterwards it may decrease
600 * it on another CPU. Always updated under the runqueue lock:
602 unsigned long nr_uninterruptible
;
604 struct task_struct
*curr
, *idle
;
605 unsigned long next_balance
;
606 struct mm_struct
*prev_mm
;
613 struct root_domain
*rd
;
614 struct sched_domain
*sd
;
616 unsigned char idle_at_tick
;
617 /* For active balancing */
620 /* cpu of this runqueue: */
624 unsigned long avg_load_per_task
;
626 struct task_struct
*migration_thread
;
627 struct list_head migration_queue
;
630 /* calc_load related fields */
631 unsigned long calc_load_update
;
632 long calc_load_active
;
634 #ifdef CONFIG_SCHED_HRTICK
636 int hrtick_csd_pending
;
637 struct call_single_data hrtick_csd
;
639 struct hrtimer hrtick_timer
;
642 #ifdef CONFIG_SCHEDSTATS
644 struct sched_info rq_sched_info
;
645 unsigned long long rq_cpu_time
;
646 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
648 /* sys_sched_yield() stats */
649 unsigned int yld_count
;
651 /* schedule() stats */
652 unsigned int sched_switch
;
653 unsigned int sched_count
;
654 unsigned int sched_goidle
;
656 /* try_to_wake_up() stats */
657 unsigned int ttwu_count
;
658 unsigned int ttwu_local
;
661 unsigned int bkl_count
;
665 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
667 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int sync
)
669 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, sync
);
672 static inline int cpu_of(struct rq
*rq
)
682 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
683 * See detach_destroy_domains: synchronize_sched for details.
685 * The domain tree of any CPU may only be accessed from within
686 * preempt-disabled sections.
688 #define for_each_domain(cpu, __sd) \
689 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
691 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
692 #define this_rq() (&__get_cpu_var(runqueues))
693 #define task_rq(p) cpu_rq(task_cpu(p))
694 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
696 inline void update_rq_clock(struct rq
*rq
)
698 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
702 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
704 #ifdef CONFIG_SCHED_DEBUG
705 # define const_debug __read_mostly
707 # define const_debug static const
713 * Returns true if the current cpu runqueue is locked.
714 * This interface allows printk to be called with the runqueue lock
715 * held and know whether or not it is OK to wake up the klogd.
717 int runqueue_is_locked(void)
720 struct rq
*rq
= cpu_rq(cpu
);
723 ret
= spin_is_locked(&rq
->lock
);
729 * Debugging: various feature bits
732 #define SCHED_FEAT(name, enabled) \
733 __SCHED_FEAT_##name ,
736 #include "sched_features.h"
741 #define SCHED_FEAT(name, enabled) \
742 (1UL << __SCHED_FEAT_##name) * enabled |
744 const_debug
unsigned int sysctl_sched_features
=
745 #include "sched_features.h"
750 #ifdef CONFIG_SCHED_DEBUG
751 #define SCHED_FEAT(name, enabled) \
754 static __read_mostly
char *sched_feat_names
[] = {
755 #include "sched_features.h"
761 static int sched_feat_show(struct seq_file
*m
, void *v
)
765 for (i
= 0; sched_feat_names
[i
]; i
++) {
766 if (!(sysctl_sched_features
& (1UL << i
)))
768 seq_printf(m
, "%s ", sched_feat_names
[i
]);
776 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
777 size_t cnt
, loff_t
*ppos
)
787 if (copy_from_user(&buf
, ubuf
, cnt
))
792 if (strncmp(buf
, "NO_", 3) == 0) {
797 for (i
= 0; sched_feat_names
[i
]; i
++) {
798 int len
= strlen(sched_feat_names
[i
]);
800 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
802 sysctl_sched_features
&= ~(1UL << i
);
804 sysctl_sched_features
|= (1UL << i
);
809 if (!sched_feat_names
[i
])
817 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
819 return single_open(filp
, sched_feat_show
, NULL
);
822 static struct file_operations sched_feat_fops
= {
823 .open
= sched_feat_open
,
824 .write
= sched_feat_write
,
827 .release
= single_release
,
830 static __init
int sched_init_debug(void)
832 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
837 late_initcall(sched_init_debug
);
841 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
844 * Number of tasks to iterate in a single balance run.
845 * Limited because this is done with IRQs disabled.
847 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
850 * ratelimit for updating the group shares.
853 unsigned int sysctl_sched_shares_ratelimit
= 250000;
856 * Inject some fuzzyness into changing the per-cpu group shares
857 * this avoids remote rq-locks at the expense of fairness.
860 unsigned int sysctl_sched_shares_thresh
= 4;
863 * period over which we measure -rt task cpu usage in us.
866 unsigned int sysctl_sched_rt_period
= 1000000;
868 static __read_mostly
int scheduler_running
;
871 * part of the period that we allow rt tasks to run in us.
874 int sysctl_sched_rt_runtime
= 950000;
876 static inline u64
global_rt_period(void)
878 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
881 static inline u64
global_rt_runtime(void)
883 if (sysctl_sched_rt_runtime
< 0)
886 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
889 #ifndef prepare_arch_switch
890 # define prepare_arch_switch(next) do { } while (0)
892 #ifndef finish_arch_switch
893 # define finish_arch_switch(prev) do { } while (0)
896 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
898 return rq
->curr
== p
;
901 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
902 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
904 return task_current(rq
, p
);
907 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
911 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
913 #ifdef CONFIG_DEBUG_SPINLOCK
914 /* this is a valid case when another task releases the spinlock */
915 rq
->lock
.owner
= current
;
918 * If we are tracking spinlock dependencies then we have to
919 * fix up the runqueue lock - which gets 'carried over' from
922 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
924 spin_unlock_irq(&rq
->lock
);
927 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
928 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
933 return task_current(rq
, p
);
937 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
941 * We can optimise this out completely for !SMP, because the
942 * SMP rebalancing from interrupt is the only thing that cares
947 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
948 spin_unlock_irq(&rq
->lock
);
950 spin_unlock(&rq
->lock
);
954 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
958 * After ->oncpu is cleared, the task can be moved to a different CPU.
959 * We must ensure this doesn't happen until the switch is completely
965 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
969 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
972 * __task_rq_lock - lock the runqueue a given task resides on.
973 * Must be called interrupts disabled.
975 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
979 struct rq
*rq
= task_rq(p
);
980 spin_lock(&rq
->lock
);
981 if (likely(rq
== task_rq(p
)))
983 spin_unlock(&rq
->lock
);
988 * task_rq_lock - lock the runqueue a given task resides on and disable
989 * interrupts. Note the ordering: we can safely lookup the task_rq without
990 * explicitly disabling preemption.
992 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
998 local_irq_save(*flags
);
1000 spin_lock(&rq
->lock
);
1001 if (likely(rq
== task_rq(p
)))
1003 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1007 void task_rq_unlock_wait(struct task_struct
*p
)
1009 struct rq
*rq
= task_rq(p
);
1011 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1012 spin_unlock_wait(&rq
->lock
);
1015 static void __task_rq_unlock(struct rq
*rq
)
1016 __releases(rq
->lock
)
1018 spin_unlock(&rq
->lock
);
1021 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
1022 __releases(rq
->lock
)
1024 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1028 * this_rq_lock - lock this runqueue and disable interrupts.
1030 static struct rq
*this_rq_lock(void)
1031 __acquires(rq
->lock
)
1035 local_irq_disable();
1037 spin_lock(&rq
->lock
);
1042 #ifdef CONFIG_SCHED_HRTICK
1044 * Use HR-timers to deliver accurate preemption points.
1046 * Its all a bit involved since we cannot program an hrt while holding the
1047 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1050 * When we get rescheduled we reprogram the hrtick_timer outside of the
1056 * - enabled by features
1057 * - hrtimer is actually high res
1059 static inline int hrtick_enabled(struct rq
*rq
)
1061 if (!sched_feat(HRTICK
))
1063 if (!cpu_active(cpu_of(rq
)))
1065 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1068 static void hrtick_clear(struct rq
*rq
)
1070 if (hrtimer_active(&rq
->hrtick_timer
))
1071 hrtimer_cancel(&rq
->hrtick_timer
);
1075 * High-resolution timer tick.
1076 * Runs from hardirq context with interrupts disabled.
1078 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1080 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1082 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1084 spin_lock(&rq
->lock
);
1085 update_rq_clock(rq
);
1086 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1087 spin_unlock(&rq
->lock
);
1089 return HRTIMER_NORESTART
;
1094 * called from hardirq (IPI) context
1096 static void __hrtick_start(void *arg
)
1098 struct rq
*rq
= arg
;
1100 spin_lock(&rq
->lock
);
1101 hrtimer_restart(&rq
->hrtick_timer
);
1102 rq
->hrtick_csd_pending
= 0;
1103 spin_unlock(&rq
->lock
);
1107 * Called to set the hrtick timer state.
1109 * called with rq->lock held and irqs disabled
1111 static void hrtick_start(struct rq
*rq
, u64 delay
)
1113 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1114 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1116 hrtimer_set_expires(timer
, time
);
1118 if (rq
== this_rq()) {
1119 hrtimer_restart(timer
);
1120 } else if (!rq
->hrtick_csd_pending
) {
1121 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1122 rq
->hrtick_csd_pending
= 1;
1127 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1129 int cpu
= (int)(long)hcpu
;
1132 case CPU_UP_CANCELED
:
1133 case CPU_UP_CANCELED_FROZEN
:
1134 case CPU_DOWN_PREPARE
:
1135 case CPU_DOWN_PREPARE_FROZEN
:
1137 case CPU_DEAD_FROZEN
:
1138 hrtick_clear(cpu_rq(cpu
));
1145 static __init
void init_hrtick(void)
1147 hotcpu_notifier(hotplug_hrtick
, 0);
1151 * Called to set the hrtick timer state.
1153 * called with rq->lock held and irqs disabled
1155 static void hrtick_start(struct rq
*rq
, u64 delay
)
1157 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1158 HRTIMER_MODE_REL_PINNED
, 0);
1161 static inline void init_hrtick(void)
1164 #endif /* CONFIG_SMP */
1166 static void init_rq_hrtick(struct rq
*rq
)
1169 rq
->hrtick_csd_pending
= 0;
1171 rq
->hrtick_csd
.flags
= 0;
1172 rq
->hrtick_csd
.func
= __hrtick_start
;
1173 rq
->hrtick_csd
.info
= rq
;
1176 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1177 rq
->hrtick_timer
.function
= hrtick
;
1179 #else /* CONFIG_SCHED_HRTICK */
1180 static inline void hrtick_clear(struct rq
*rq
)
1184 static inline void init_rq_hrtick(struct rq
*rq
)
1188 static inline void init_hrtick(void)
1191 #endif /* CONFIG_SCHED_HRTICK */
1194 * resched_task - mark a task 'to be rescheduled now'.
1196 * On UP this means the setting of the need_resched flag, on SMP it
1197 * might also involve a cross-CPU call to trigger the scheduler on
1202 #ifndef tsk_is_polling
1203 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1206 static void resched_task(struct task_struct
*p
)
1210 assert_spin_locked(&task_rq(p
)->lock
);
1212 if (test_tsk_need_resched(p
))
1215 set_tsk_need_resched(p
);
1218 if (cpu
== smp_processor_id())
1221 /* NEED_RESCHED must be visible before we test polling */
1223 if (!tsk_is_polling(p
))
1224 smp_send_reschedule(cpu
);
1227 static void resched_cpu(int cpu
)
1229 struct rq
*rq
= cpu_rq(cpu
);
1230 unsigned long flags
;
1232 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1234 resched_task(cpu_curr(cpu
));
1235 spin_unlock_irqrestore(&rq
->lock
, flags
);
1240 * When add_timer_on() enqueues a timer into the timer wheel of an
1241 * idle CPU then this timer might expire before the next timer event
1242 * which is scheduled to wake up that CPU. In case of a completely
1243 * idle system the next event might even be infinite time into the
1244 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1245 * leaves the inner idle loop so the newly added timer is taken into
1246 * account when the CPU goes back to idle and evaluates the timer
1247 * wheel for the next timer event.
1249 void wake_up_idle_cpu(int cpu
)
1251 struct rq
*rq
= cpu_rq(cpu
);
1253 if (cpu
== smp_processor_id())
1257 * This is safe, as this function is called with the timer
1258 * wheel base lock of (cpu) held. When the CPU is on the way
1259 * to idle and has not yet set rq->curr to idle then it will
1260 * be serialized on the timer wheel base lock and take the new
1261 * timer into account automatically.
1263 if (rq
->curr
!= rq
->idle
)
1267 * We can set TIF_RESCHED on the idle task of the other CPU
1268 * lockless. The worst case is that the other CPU runs the
1269 * idle task through an additional NOOP schedule()
1271 set_tsk_need_resched(rq
->idle
);
1273 /* NEED_RESCHED must be visible before we test polling */
1275 if (!tsk_is_polling(rq
->idle
))
1276 smp_send_reschedule(cpu
);
1278 #endif /* CONFIG_NO_HZ */
1280 #else /* !CONFIG_SMP */
1281 static void resched_task(struct task_struct
*p
)
1283 assert_spin_locked(&task_rq(p
)->lock
);
1284 set_tsk_need_resched(p
);
1286 #endif /* CONFIG_SMP */
1288 #if BITS_PER_LONG == 32
1289 # define WMULT_CONST (~0UL)
1291 # define WMULT_CONST (1UL << 32)
1294 #define WMULT_SHIFT 32
1297 * Shift right and round:
1299 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1302 * delta *= weight / lw
1304 static unsigned long
1305 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1306 struct load_weight
*lw
)
1310 if (!lw
->inv_weight
) {
1311 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1314 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1318 tmp
= (u64
)delta_exec
* weight
;
1320 * Check whether we'd overflow the 64-bit multiplication:
1322 if (unlikely(tmp
> WMULT_CONST
))
1323 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1326 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1328 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1331 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1337 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1344 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1345 * of tasks with abnormal "nice" values across CPUs the contribution that
1346 * each task makes to its run queue's load is weighted according to its
1347 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1348 * scaled version of the new time slice allocation that they receive on time
1352 #define WEIGHT_IDLEPRIO 3
1353 #define WMULT_IDLEPRIO 1431655765
1356 * Nice levels are multiplicative, with a gentle 10% change for every
1357 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1358 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1359 * that remained on nice 0.
1361 * The "10% effect" is relative and cumulative: from _any_ nice level,
1362 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1363 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1364 * If a task goes up by ~10% and another task goes down by ~10% then
1365 * the relative distance between them is ~25%.)
1367 static const int prio_to_weight
[40] = {
1368 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1369 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1370 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1371 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1372 /* 0 */ 1024, 820, 655, 526, 423,
1373 /* 5 */ 335, 272, 215, 172, 137,
1374 /* 10 */ 110, 87, 70, 56, 45,
1375 /* 15 */ 36, 29, 23, 18, 15,
1379 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1381 * In cases where the weight does not change often, we can use the
1382 * precalculated inverse to speed up arithmetics by turning divisions
1383 * into multiplications:
1385 static const u32 prio_to_wmult
[40] = {
1386 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1387 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1388 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1389 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1390 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1391 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1392 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1393 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1396 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1399 * runqueue iterator, to support SMP load-balancing between different
1400 * scheduling classes, without having to expose their internal data
1401 * structures to the load-balancing proper:
1403 struct rq_iterator
{
1405 struct task_struct
*(*start
)(void *);
1406 struct task_struct
*(*next
)(void *);
1410 static unsigned long
1411 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1412 unsigned long max_load_move
, struct sched_domain
*sd
,
1413 enum cpu_idle_type idle
, int *all_pinned
,
1414 int *this_best_prio
, struct rq_iterator
*iterator
);
1417 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1418 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1419 struct rq_iterator
*iterator
);
1422 /* Time spent by the tasks of the cpu accounting group executing in ... */
1423 enum cpuacct_stat_index
{
1424 CPUACCT_STAT_USER
, /* ... user mode */
1425 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1427 CPUACCT_STAT_NSTATS
,
1430 #ifdef CONFIG_CGROUP_CPUACCT
1431 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1432 static void cpuacct_update_stats(struct task_struct
*tsk
,
1433 enum cpuacct_stat_index idx
, cputime_t val
);
1435 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1436 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1437 enum cpuacct_stat_index idx
, cputime_t val
) {}
1440 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1442 update_load_add(&rq
->load
, load
);
1445 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1447 update_load_sub(&rq
->load
, load
);
1450 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1451 typedef int (*tg_visitor
)(struct task_group
*, void *);
1454 * Iterate the full tree, calling @down when first entering a node and @up when
1455 * leaving it for the final time.
1457 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1459 struct task_group
*parent
, *child
;
1463 parent
= &root_task_group
;
1465 ret
= (*down
)(parent
, data
);
1468 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1475 ret
= (*up
)(parent
, data
);
1480 parent
= parent
->parent
;
1489 static int tg_nop(struct task_group
*tg
, void *data
)
1496 static unsigned long source_load(int cpu
, int type
);
1497 static unsigned long target_load(int cpu
, int type
);
1498 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1500 static unsigned long cpu_avg_load_per_task(int cpu
)
1502 struct rq
*rq
= cpu_rq(cpu
);
1503 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1506 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1508 rq
->avg_load_per_task
= 0;
1510 return rq
->avg_load_per_task
;
1513 #ifdef CONFIG_FAIR_GROUP_SCHED
1515 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1518 * Calculate and set the cpu's group shares.
1521 update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1522 unsigned long sd_shares
, unsigned long sd_rq_weight
)
1524 unsigned long shares
;
1525 unsigned long rq_weight
;
1530 rq_weight
= tg
->cfs_rq
[cpu
]->rq_weight
;
1533 * \Sum shares * rq_weight
1534 * shares = -----------------------
1538 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1539 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1541 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1542 sysctl_sched_shares_thresh
) {
1543 struct rq
*rq
= cpu_rq(cpu
);
1544 unsigned long flags
;
1546 spin_lock_irqsave(&rq
->lock
, flags
);
1547 tg
->cfs_rq
[cpu
]->shares
= shares
;
1549 __set_se_shares(tg
->se
[cpu
], shares
);
1550 spin_unlock_irqrestore(&rq
->lock
, flags
);
1555 * Re-compute the task group their per cpu shares over the given domain.
1556 * This needs to be done in a bottom-up fashion because the rq weight of a
1557 * parent group depends on the shares of its child groups.
1559 static int tg_shares_up(struct task_group
*tg
, void *data
)
1561 unsigned long weight
, rq_weight
= 0;
1562 unsigned long shares
= 0;
1563 struct sched_domain
*sd
= data
;
1566 for_each_cpu(i
, sched_domain_span(sd
)) {
1568 * If there are currently no tasks on the cpu pretend there
1569 * is one of average load so that when a new task gets to
1570 * run here it will not get delayed by group starvation.
1572 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1574 weight
= NICE_0_LOAD
;
1576 tg
->cfs_rq
[i
]->rq_weight
= weight
;
1577 rq_weight
+= weight
;
1578 shares
+= tg
->cfs_rq
[i
]->shares
;
1581 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1582 shares
= tg
->shares
;
1584 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1585 shares
= tg
->shares
;
1587 for_each_cpu(i
, sched_domain_span(sd
))
1588 update_group_shares_cpu(tg
, i
, shares
, rq_weight
);
1594 * Compute the cpu's hierarchical load factor for each task group.
1595 * This needs to be done in a top-down fashion because the load of a child
1596 * group is a fraction of its parents load.
1598 static int tg_load_down(struct task_group
*tg
, void *data
)
1601 long cpu
= (long)data
;
1604 load
= cpu_rq(cpu
)->load
.weight
;
1606 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1607 load
*= tg
->cfs_rq
[cpu
]->shares
;
1608 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1611 tg
->cfs_rq
[cpu
]->h_load
= load
;
1616 static void update_shares(struct sched_domain
*sd
)
1618 u64 now
= cpu_clock(raw_smp_processor_id());
1619 s64 elapsed
= now
- sd
->last_update
;
1621 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1622 sd
->last_update
= now
;
1623 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1627 static void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1629 spin_unlock(&rq
->lock
);
1631 spin_lock(&rq
->lock
);
1634 static void update_h_load(long cpu
)
1636 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1641 static inline void update_shares(struct sched_domain
*sd
)
1645 static inline void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1651 #ifdef CONFIG_PREEMPT
1654 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1655 * way at the expense of forcing extra atomic operations in all
1656 * invocations. This assures that the double_lock is acquired using the
1657 * same underlying policy as the spinlock_t on this architecture, which
1658 * reduces latency compared to the unfair variant below. However, it
1659 * also adds more overhead and therefore may reduce throughput.
1661 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1662 __releases(this_rq
->lock
)
1663 __acquires(busiest
->lock
)
1664 __acquires(this_rq
->lock
)
1666 spin_unlock(&this_rq
->lock
);
1667 double_rq_lock(this_rq
, busiest
);
1674 * Unfair double_lock_balance: Optimizes throughput at the expense of
1675 * latency by eliminating extra atomic operations when the locks are
1676 * already in proper order on entry. This favors lower cpu-ids and will
1677 * grant the double lock to lower cpus over higher ids under contention,
1678 * regardless of entry order into the function.
1680 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1681 __releases(this_rq
->lock
)
1682 __acquires(busiest
->lock
)
1683 __acquires(this_rq
->lock
)
1687 if (unlikely(!spin_trylock(&busiest
->lock
))) {
1688 if (busiest
< this_rq
) {
1689 spin_unlock(&this_rq
->lock
);
1690 spin_lock(&busiest
->lock
);
1691 spin_lock_nested(&this_rq
->lock
, SINGLE_DEPTH_NESTING
);
1694 spin_lock_nested(&busiest
->lock
, SINGLE_DEPTH_NESTING
);
1699 #endif /* CONFIG_PREEMPT */
1702 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1704 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1706 if (unlikely(!irqs_disabled())) {
1707 /* printk() doesn't work good under rq->lock */
1708 spin_unlock(&this_rq
->lock
);
1712 return _double_lock_balance(this_rq
, busiest
);
1715 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1716 __releases(busiest
->lock
)
1718 spin_unlock(&busiest
->lock
);
1719 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1723 #ifdef CONFIG_FAIR_GROUP_SCHED
1724 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1727 cfs_rq
->shares
= shares
;
1732 static void calc_load_account_active(struct rq
*this_rq
);
1734 #include "sched_stats.h"
1735 #include "sched_idletask.c"
1736 #include "sched_fair.c"
1737 #include "sched_rt.c"
1738 #ifdef CONFIG_SCHED_DEBUG
1739 # include "sched_debug.c"
1742 #define sched_class_highest (&rt_sched_class)
1743 #define for_each_class(class) \
1744 for (class = sched_class_highest; class; class = class->next)
1746 static void inc_nr_running(struct rq
*rq
)
1751 static void dec_nr_running(struct rq
*rq
)
1756 static void set_load_weight(struct task_struct
*p
)
1758 if (task_has_rt_policy(p
)) {
1759 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1760 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1765 * SCHED_IDLE tasks get minimal weight:
1767 if (p
->policy
== SCHED_IDLE
) {
1768 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1769 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1773 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1774 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1777 static void update_avg(u64
*avg
, u64 sample
)
1779 s64 diff
= sample
- *avg
;
1783 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1786 p
->se
.start_runtime
= p
->se
.sum_exec_runtime
;
1788 sched_info_queued(p
);
1789 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1793 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1796 if (p
->se
.last_wakeup
) {
1797 update_avg(&p
->se
.avg_overlap
,
1798 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1799 p
->se
.last_wakeup
= 0;
1801 update_avg(&p
->se
.avg_wakeup
,
1802 sysctl_sched_wakeup_granularity
);
1806 sched_info_dequeued(p
);
1807 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1812 * __normal_prio - return the priority that is based on the static prio
1814 static inline int __normal_prio(struct task_struct
*p
)
1816 return p
->static_prio
;
1820 * Calculate the expected normal priority: i.e. priority
1821 * without taking RT-inheritance into account. Might be
1822 * boosted by interactivity modifiers. Changes upon fork,
1823 * setprio syscalls, and whenever the interactivity
1824 * estimator recalculates.
1826 static inline int normal_prio(struct task_struct
*p
)
1830 if (task_has_rt_policy(p
))
1831 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1833 prio
= __normal_prio(p
);
1838 * Calculate the current priority, i.e. the priority
1839 * taken into account by the scheduler. This value might
1840 * be boosted by RT tasks, or might be boosted by
1841 * interactivity modifiers. Will be RT if the task got
1842 * RT-boosted. If not then it returns p->normal_prio.
1844 static int effective_prio(struct task_struct
*p
)
1846 p
->normal_prio
= normal_prio(p
);
1848 * If we are RT tasks or we were boosted to RT priority,
1849 * keep the priority unchanged. Otherwise, update priority
1850 * to the normal priority:
1852 if (!rt_prio(p
->prio
))
1853 return p
->normal_prio
;
1858 * activate_task - move a task to the runqueue.
1860 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1862 if (task_contributes_to_load(p
))
1863 rq
->nr_uninterruptible
--;
1865 enqueue_task(rq
, p
, wakeup
);
1870 * deactivate_task - remove a task from the runqueue.
1872 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1874 if (task_contributes_to_load(p
))
1875 rq
->nr_uninterruptible
++;
1877 dequeue_task(rq
, p
, sleep
);
1882 * task_curr - is this task currently executing on a CPU?
1883 * @p: the task in question.
1885 inline int task_curr(const struct task_struct
*p
)
1887 return cpu_curr(task_cpu(p
)) == p
;
1890 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1892 set_task_rq(p
, cpu
);
1895 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1896 * successfuly executed on another CPU. We must ensure that updates of
1897 * per-task data have been completed by this moment.
1900 task_thread_info(p
)->cpu
= cpu
;
1904 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1905 const struct sched_class
*prev_class
,
1906 int oldprio
, int running
)
1908 if (prev_class
!= p
->sched_class
) {
1909 if (prev_class
->switched_from
)
1910 prev_class
->switched_from(rq
, p
, running
);
1911 p
->sched_class
->switched_to(rq
, p
, running
);
1913 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1918 /* Used instead of source_load when we know the type == 0 */
1919 static unsigned long weighted_cpuload(const int cpu
)
1921 return cpu_rq(cpu
)->load
.weight
;
1925 * Is this task likely cache-hot:
1928 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1933 * Buddy candidates are cache hot:
1935 if (sched_feat(CACHE_HOT_BUDDY
) &&
1936 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
1937 &p
->se
== cfs_rq_of(&p
->se
)->last
))
1940 if (p
->sched_class
!= &fair_sched_class
)
1943 if (sysctl_sched_migration_cost
== -1)
1945 if (sysctl_sched_migration_cost
== 0)
1948 delta
= now
- p
->se
.exec_start
;
1950 return delta
< (s64
)sysctl_sched_migration_cost
;
1954 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1956 int old_cpu
= task_cpu(p
);
1957 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1958 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1959 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1962 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1964 trace_sched_migrate_task(p
, new_cpu
);
1966 #ifdef CONFIG_SCHEDSTATS
1967 if (p
->se
.wait_start
)
1968 p
->se
.wait_start
-= clock_offset
;
1969 if (p
->se
.sleep_start
)
1970 p
->se
.sleep_start
-= clock_offset
;
1971 if (p
->se
.block_start
)
1972 p
->se
.block_start
-= clock_offset
;
1974 if (old_cpu
!= new_cpu
) {
1975 p
->se
.nr_migrations
++;
1976 new_rq
->nr_migrations_in
++;
1977 #ifdef CONFIG_SCHEDSTATS
1978 if (task_hot(p
, old_rq
->clock
, NULL
))
1979 schedstat_inc(p
, se
.nr_forced2_migrations
);
1981 perf_swcounter_event(PERF_COUNT_SW_CPU_MIGRATIONS
,
1984 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1985 new_cfsrq
->min_vruntime
;
1987 __set_task_cpu(p
, new_cpu
);
1990 struct migration_req
{
1991 struct list_head list
;
1993 struct task_struct
*task
;
1996 struct completion done
;
2000 * The task's runqueue lock must be held.
2001 * Returns true if you have to wait for migration thread.
2004 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
2006 struct rq
*rq
= task_rq(p
);
2009 * If the task is not on a runqueue (and not running), then
2010 * it is sufficient to simply update the task's cpu field.
2012 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
2013 set_task_cpu(p
, dest_cpu
);
2017 init_completion(&req
->done
);
2019 req
->dest_cpu
= dest_cpu
;
2020 list_add(&req
->list
, &rq
->migration_queue
);
2026 * wait_task_context_switch - wait for a thread to complete at least one
2029 * @p must not be current.
2031 void wait_task_context_switch(struct task_struct
*p
)
2033 unsigned long nvcsw
, nivcsw
, flags
;
2041 * The runqueue is assigned before the actual context
2042 * switch. We need to take the runqueue lock.
2044 * We could check initially without the lock but it is
2045 * very likely that we need to take the lock in every
2048 rq
= task_rq_lock(p
, &flags
);
2049 running
= task_running(rq
, p
);
2050 task_rq_unlock(rq
, &flags
);
2052 if (likely(!running
))
2055 * The switch count is incremented before the actual
2056 * context switch. We thus wait for two switches to be
2057 * sure at least one completed.
2059 if ((p
->nvcsw
- nvcsw
) > 1)
2061 if ((p
->nivcsw
- nivcsw
) > 1)
2069 * wait_task_inactive - wait for a thread to unschedule.
2071 * If @match_state is nonzero, it's the @p->state value just checked and
2072 * not expected to change. If it changes, i.e. @p might have woken up,
2073 * then return zero. When we succeed in waiting for @p to be off its CPU,
2074 * we return a positive number (its total switch count). If a second call
2075 * a short while later returns the same number, the caller can be sure that
2076 * @p has remained unscheduled the whole time.
2078 * The caller must ensure that the task *will* unschedule sometime soon,
2079 * else this function might spin for a *long* time. This function can't
2080 * be called with interrupts off, or it may introduce deadlock with
2081 * smp_call_function() if an IPI is sent by the same process we are
2082 * waiting to become inactive.
2084 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2086 unsigned long flags
;
2093 * We do the initial early heuristics without holding
2094 * any task-queue locks at all. We'll only try to get
2095 * the runqueue lock when things look like they will
2101 * If the task is actively running on another CPU
2102 * still, just relax and busy-wait without holding
2105 * NOTE! Since we don't hold any locks, it's not
2106 * even sure that "rq" stays as the right runqueue!
2107 * But we don't care, since "task_running()" will
2108 * return false if the runqueue has changed and p
2109 * is actually now running somewhere else!
2111 while (task_running(rq
, p
)) {
2112 if (match_state
&& unlikely(p
->state
!= match_state
))
2118 * Ok, time to look more closely! We need the rq
2119 * lock now, to be *sure*. If we're wrong, we'll
2120 * just go back and repeat.
2122 rq
= task_rq_lock(p
, &flags
);
2123 trace_sched_wait_task(rq
, p
);
2124 running
= task_running(rq
, p
);
2125 on_rq
= p
->se
.on_rq
;
2127 if (!match_state
|| p
->state
== match_state
)
2128 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2129 task_rq_unlock(rq
, &flags
);
2132 * If it changed from the expected state, bail out now.
2134 if (unlikely(!ncsw
))
2138 * Was it really running after all now that we
2139 * checked with the proper locks actually held?
2141 * Oops. Go back and try again..
2143 if (unlikely(running
)) {
2149 * It's not enough that it's not actively running,
2150 * it must be off the runqueue _entirely_, and not
2153 * So if it was still runnable (but just not actively
2154 * running right now), it's preempted, and we should
2155 * yield - it could be a while.
2157 if (unlikely(on_rq
)) {
2158 schedule_timeout_uninterruptible(1);
2163 * Ahh, all good. It wasn't running, and it wasn't
2164 * runnable, which means that it will never become
2165 * running in the future either. We're all done!
2174 * kick_process - kick a running thread to enter/exit the kernel
2175 * @p: the to-be-kicked thread
2177 * Cause a process which is running on another CPU to enter
2178 * kernel-mode, without any delay. (to get signals handled.)
2180 * NOTE: this function doesnt have to take the runqueue lock,
2181 * because all it wants to ensure is that the remote task enters
2182 * the kernel. If the IPI races and the task has been migrated
2183 * to another CPU then no harm is done and the purpose has been
2186 void kick_process(struct task_struct
*p
)
2192 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2193 smp_send_reschedule(cpu
);
2196 EXPORT_SYMBOL_GPL(kick_process
);
2199 * Return a low guess at the load of a migration-source cpu weighted
2200 * according to the scheduling class and "nice" value.
2202 * We want to under-estimate the load of migration sources, to
2203 * balance conservatively.
2205 static unsigned long source_load(int cpu
, int type
)
2207 struct rq
*rq
= cpu_rq(cpu
);
2208 unsigned long total
= weighted_cpuload(cpu
);
2210 if (type
== 0 || !sched_feat(LB_BIAS
))
2213 return min(rq
->cpu_load
[type
-1], total
);
2217 * Return a high guess at the load of a migration-target cpu weighted
2218 * according to the scheduling class and "nice" value.
2220 static unsigned long target_load(int cpu
, int type
)
2222 struct rq
*rq
= cpu_rq(cpu
);
2223 unsigned long total
= weighted_cpuload(cpu
);
2225 if (type
== 0 || !sched_feat(LB_BIAS
))
2228 return max(rq
->cpu_load
[type
-1], total
);
2232 * find_idlest_group finds and returns the least busy CPU group within the
2235 static struct sched_group
*
2236 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
2238 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2239 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
2240 int load_idx
= sd
->forkexec_idx
;
2241 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
2244 unsigned long load
, avg_load
;
2248 /* Skip over this group if it has no CPUs allowed */
2249 if (!cpumask_intersects(sched_group_cpus(group
),
2253 local_group
= cpumask_test_cpu(this_cpu
,
2254 sched_group_cpus(group
));
2256 /* Tally up the load of all CPUs in the group */
2259 for_each_cpu(i
, sched_group_cpus(group
)) {
2260 /* Bias balancing toward cpus of our domain */
2262 load
= source_load(i
, load_idx
);
2264 load
= target_load(i
, load_idx
);
2269 /* Adjust by relative CPU power of the group */
2270 avg_load
= sg_div_cpu_power(group
,
2271 avg_load
* SCHED_LOAD_SCALE
);
2274 this_load
= avg_load
;
2276 } else if (avg_load
< min_load
) {
2277 min_load
= avg_load
;
2280 } while (group
= group
->next
, group
!= sd
->groups
);
2282 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
2288 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2291 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
)
2293 unsigned long load
, min_load
= ULONG_MAX
;
2297 /* Traverse only the allowed CPUs */
2298 for_each_cpu_and(i
, sched_group_cpus(group
), &p
->cpus_allowed
) {
2299 load
= weighted_cpuload(i
);
2301 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
2311 * sched_balance_self: balance the current task (running on cpu) in domains
2312 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2315 * Balance, ie. select the least loaded group.
2317 * Returns the target CPU number, or the same CPU if no balancing is needed.
2319 * preempt must be disabled.
2321 static int sched_balance_self(int cpu
, int flag
)
2323 struct task_struct
*t
= current
;
2324 struct sched_domain
*tmp
, *sd
= NULL
;
2326 for_each_domain(cpu
, tmp
) {
2328 * If power savings logic is enabled for a domain, stop there.
2330 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2332 if (tmp
->flags
& flag
)
2340 struct sched_group
*group
;
2341 int new_cpu
, weight
;
2343 if (!(sd
->flags
& flag
)) {
2348 group
= find_idlest_group(sd
, t
, cpu
);
2354 new_cpu
= find_idlest_cpu(group
, t
, cpu
);
2355 if (new_cpu
== -1 || new_cpu
== cpu
) {
2356 /* Now try balancing at a lower domain level of cpu */
2361 /* Now try balancing at a lower domain level of new_cpu */
2363 weight
= cpumask_weight(sched_domain_span(sd
));
2365 for_each_domain(cpu
, tmp
) {
2366 if (weight
<= cpumask_weight(sched_domain_span(tmp
)))
2368 if (tmp
->flags
& flag
)
2371 /* while loop will break here if sd == NULL */
2377 #endif /* CONFIG_SMP */
2380 * task_oncpu_function_call - call a function on the cpu on which a task runs
2381 * @p: the task to evaluate
2382 * @func: the function to be called
2383 * @info: the function call argument
2385 * Calls the function @func when the task is currently running. This might
2386 * be on the current CPU, which just calls the function directly
2388 void task_oncpu_function_call(struct task_struct
*p
,
2389 void (*func
) (void *info
), void *info
)
2396 smp_call_function_single(cpu
, func
, info
, 1);
2401 * try_to_wake_up - wake up a thread
2402 * @p: the to-be-woken-up thread
2403 * @state: the mask of task states that can be woken
2404 * @sync: do a synchronous wakeup?
2406 * Put it on the run-queue if it's not already there. The "current"
2407 * thread is always on the run-queue (except when the actual
2408 * re-schedule is in progress), and as such you're allowed to do
2409 * the simpler "current->state = TASK_RUNNING" to mark yourself
2410 * runnable without the overhead of this.
2412 * returns failure only if the task is already active.
2414 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2416 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2417 unsigned long flags
;
2421 if (!sched_feat(SYNC_WAKEUPS
))
2425 if (sched_feat(LB_WAKEUP_UPDATE
) && !root_task_group_empty()) {
2426 struct sched_domain
*sd
;
2428 this_cpu
= raw_smp_processor_id();
2431 for_each_domain(this_cpu
, sd
) {
2432 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2441 rq
= task_rq_lock(p
, &flags
);
2442 update_rq_clock(rq
);
2443 old_state
= p
->state
;
2444 if (!(old_state
& state
))
2452 this_cpu
= smp_processor_id();
2455 if (unlikely(task_running(rq
, p
)))
2458 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2459 if (cpu
!= orig_cpu
) {
2460 set_task_cpu(p
, cpu
);
2461 task_rq_unlock(rq
, &flags
);
2462 /* might preempt at this point */
2463 rq
= task_rq_lock(p
, &flags
);
2464 old_state
= p
->state
;
2465 if (!(old_state
& state
))
2470 this_cpu
= smp_processor_id();
2474 #ifdef CONFIG_SCHEDSTATS
2475 schedstat_inc(rq
, ttwu_count
);
2476 if (cpu
== this_cpu
)
2477 schedstat_inc(rq
, ttwu_local
);
2479 struct sched_domain
*sd
;
2480 for_each_domain(this_cpu
, sd
) {
2481 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2482 schedstat_inc(sd
, ttwu_wake_remote
);
2487 #endif /* CONFIG_SCHEDSTATS */
2490 #endif /* CONFIG_SMP */
2491 schedstat_inc(p
, se
.nr_wakeups
);
2493 schedstat_inc(p
, se
.nr_wakeups_sync
);
2494 if (orig_cpu
!= cpu
)
2495 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2496 if (cpu
== this_cpu
)
2497 schedstat_inc(p
, se
.nr_wakeups_local
);
2499 schedstat_inc(p
, se
.nr_wakeups_remote
);
2500 activate_task(rq
, p
, 1);
2504 * Only attribute actual wakeups done by this task.
2506 if (!in_interrupt()) {
2507 struct sched_entity
*se
= ¤t
->se
;
2508 u64 sample
= se
->sum_exec_runtime
;
2510 if (se
->last_wakeup
)
2511 sample
-= se
->last_wakeup
;
2513 sample
-= se
->start_runtime
;
2514 update_avg(&se
->avg_wakeup
, sample
);
2516 se
->last_wakeup
= se
->sum_exec_runtime
;
2520 trace_sched_wakeup(rq
, p
, success
);
2521 check_preempt_curr(rq
, p
, sync
);
2523 p
->state
= TASK_RUNNING
;
2525 if (p
->sched_class
->task_wake_up
)
2526 p
->sched_class
->task_wake_up(rq
, p
);
2529 task_rq_unlock(rq
, &flags
);
2535 * wake_up_process - Wake up a specific process
2536 * @p: The process to be woken up.
2538 * Attempt to wake up the nominated process and move it to the set of runnable
2539 * processes. Returns 1 if the process was woken up, 0 if it was already
2542 * It may be assumed that this function implies a write memory barrier before
2543 * changing the task state if and only if any tasks are woken up.
2545 int wake_up_process(struct task_struct
*p
)
2547 return try_to_wake_up(p
, TASK_ALL
, 0);
2549 EXPORT_SYMBOL(wake_up_process
);
2551 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2553 return try_to_wake_up(p
, state
, 0);
2557 * Perform scheduler related setup for a newly forked process p.
2558 * p is forked by current.
2560 * __sched_fork() is basic setup used by init_idle() too:
2562 static void __sched_fork(struct task_struct
*p
)
2564 p
->se
.exec_start
= 0;
2565 p
->se
.sum_exec_runtime
= 0;
2566 p
->se
.prev_sum_exec_runtime
= 0;
2567 p
->se
.nr_migrations
= 0;
2568 p
->se
.last_wakeup
= 0;
2569 p
->se
.avg_overlap
= 0;
2570 p
->se
.start_runtime
= 0;
2571 p
->se
.avg_wakeup
= sysctl_sched_wakeup_granularity
;
2573 #ifdef CONFIG_SCHEDSTATS
2574 p
->se
.wait_start
= 0;
2575 p
->se
.sum_sleep_runtime
= 0;
2576 p
->se
.sleep_start
= 0;
2577 p
->se
.block_start
= 0;
2578 p
->se
.sleep_max
= 0;
2579 p
->se
.block_max
= 0;
2581 p
->se
.slice_max
= 0;
2585 INIT_LIST_HEAD(&p
->rt
.run_list
);
2587 INIT_LIST_HEAD(&p
->se
.group_node
);
2589 #ifdef CONFIG_PREEMPT_NOTIFIERS
2590 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2594 * We mark the process as running here, but have not actually
2595 * inserted it onto the runqueue yet. This guarantees that
2596 * nobody will actually run it, and a signal or other external
2597 * event cannot wake it up and insert it on the runqueue either.
2599 p
->state
= TASK_RUNNING
;
2603 * fork()/clone()-time setup:
2605 void sched_fork(struct task_struct
*p
, int clone_flags
)
2607 int cpu
= get_cpu();
2612 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2614 set_task_cpu(p
, cpu
);
2617 * Make sure we do not leak PI boosting priority to the child.
2619 p
->prio
= current
->normal_prio
;
2622 * Revert to default priority/policy on fork if requested.
2624 if (unlikely(p
->sched_reset_on_fork
)) {
2625 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
)
2626 p
->policy
= SCHED_NORMAL
;
2628 if (p
->normal_prio
< DEFAULT_PRIO
)
2629 p
->prio
= DEFAULT_PRIO
;
2631 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2632 p
->static_prio
= NICE_TO_PRIO(0);
2637 * We don't need the reset flag anymore after the fork. It has
2638 * fulfilled its duty:
2640 p
->sched_reset_on_fork
= 0;
2643 if (!rt_prio(p
->prio
))
2644 p
->sched_class
= &fair_sched_class
;
2646 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2647 if (likely(sched_info_on()))
2648 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2650 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2653 #ifdef CONFIG_PREEMPT
2654 /* Want to start with kernel preemption disabled. */
2655 task_thread_info(p
)->preempt_count
= 1;
2657 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2663 * wake_up_new_task - wake up a newly created task for the first time.
2665 * This function will do some initial scheduler statistics housekeeping
2666 * that must be done for every newly created context, then puts the task
2667 * on the runqueue and wakes it.
2669 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2671 unsigned long flags
;
2674 rq
= task_rq_lock(p
, &flags
);
2675 BUG_ON(p
->state
!= TASK_RUNNING
);
2676 update_rq_clock(rq
);
2678 p
->prio
= effective_prio(p
);
2680 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2681 activate_task(rq
, p
, 0);
2684 * Let the scheduling class do new task startup
2685 * management (if any):
2687 p
->sched_class
->task_new(rq
, p
);
2690 trace_sched_wakeup_new(rq
, p
, 1);
2691 check_preempt_curr(rq
, p
, 0);
2693 if (p
->sched_class
->task_wake_up
)
2694 p
->sched_class
->task_wake_up(rq
, p
);
2696 task_rq_unlock(rq
, &flags
);
2699 #ifdef CONFIG_PREEMPT_NOTIFIERS
2702 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2703 * @notifier: notifier struct to register
2705 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2707 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2709 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2712 * preempt_notifier_unregister - no longer interested in preemption notifications
2713 * @notifier: notifier struct to unregister
2715 * This is safe to call from within a preemption notifier.
2717 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2719 hlist_del(¬ifier
->link
);
2721 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2723 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2725 struct preempt_notifier
*notifier
;
2726 struct hlist_node
*node
;
2728 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2729 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2733 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2734 struct task_struct
*next
)
2736 struct preempt_notifier
*notifier
;
2737 struct hlist_node
*node
;
2739 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2740 notifier
->ops
->sched_out(notifier
, next
);
2743 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2745 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2750 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2751 struct task_struct
*next
)
2755 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2758 * prepare_task_switch - prepare to switch tasks
2759 * @rq: the runqueue preparing to switch
2760 * @prev: the current task that is being switched out
2761 * @next: the task we are going to switch to.
2763 * This is called with the rq lock held and interrupts off. It must
2764 * be paired with a subsequent finish_task_switch after the context
2767 * prepare_task_switch sets up locking and calls architecture specific
2771 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2772 struct task_struct
*next
)
2774 fire_sched_out_preempt_notifiers(prev
, next
);
2775 prepare_lock_switch(rq
, next
);
2776 prepare_arch_switch(next
);
2780 * finish_task_switch - clean up after a task-switch
2781 * @rq: runqueue associated with task-switch
2782 * @prev: the thread we just switched away from.
2784 * finish_task_switch must be called after the context switch, paired
2785 * with a prepare_task_switch call before the context switch.
2786 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2787 * and do any other architecture-specific cleanup actions.
2789 * Note that we may have delayed dropping an mm in context_switch(). If
2790 * so, we finish that here outside of the runqueue lock. (Doing it
2791 * with the lock held can cause deadlocks; see schedule() for
2794 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2795 __releases(rq
->lock
)
2797 struct mm_struct
*mm
= rq
->prev_mm
;
2800 int post_schedule
= 0;
2802 if (current
->sched_class
->needs_post_schedule
)
2803 post_schedule
= current
->sched_class
->needs_post_schedule(rq
);
2809 * A task struct has one reference for the use as "current".
2810 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2811 * schedule one last time. The schedule call will never return, and
2812 * the scheduled task must drop that reference.
2813 * The test for TASK_DEAD must occur while the runqueue locks are
2814 * still held, otherwise prev could be scheduled on another cpu, die
2815 * there before we look at prev->state, and then the reference would
2817 * Manfred Spraul <manfred@colorfullife.com>
2819 prev_state
= prev
->state
;
2820 finish_arch_switch(prev
);
2821 perf_counter_task_sched_in(current
, cpu_of(rq
));
2822 finish_lock_switch(rq
, prev
);
2825 current
->sched_class
->post_schedule(rq
);
2828 fire_sched_in_preempt_notifiers(current
);
2831 if (unlikely(prev_state
== TASK_DEAD
)) {
2833 * Remove function-return probe instances associated with this
2834 * task and put them back on the free list.
2836 kprobe_flush_task(prev
);
2837 put_task_struct(prev
);
2842 * schedule_tail - first thing a freshly forked thread must call.
2843 * @prev: the thread we just switched away from.
2845 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2846 __releases(rq
->lock
)
2848 struct rq
*rq
= this_rq();
2850 finish_task_switch(rq
, prev
);
2851 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2852 /* In this case, finish_task_switch does not reenable preemption */
2855 if (current
->set_child_tid
)
2856 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2860 * context_switch - switch to the new MM and the new
2861 * thread's register state.
2864 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2865 struct task_struct
*next
)
2867 struct mm_struct
*mm
, *oldmm
;
2869 prepare_task_switch(rq
, prev
, next
);
2870 trace_sched_switch(rq
, prev
, next
);
2872 oldmm
= prev
->active_mm
;
2874 * For paravirt, this is coupled with an exit in switch_to to
2875 * combine the page table reload and the switch backend into
2878 arch_start_context_switch(prev
);
2880 if (unlikely(!mm
)) {
2881 next
->active_mm
= oldmm
;
2882 atomic_inc(&oldmm
->mm_count
);
2883 enter_lazy_tlb(oldmm
, next
);
2885 switch_mm(oldmm
, mm
, next
);
2887 if (unlikely(!prev
->mm
)) {
2888 prev
->active_mm
= NULL
;
2889 rq
->prev_mm
= oldmm
;
2892 * Since the runqueue lock will be released by the next
2893 * task (which is an invalid locking op but in the case
2894 * of the scheduler it's an obvious special-case), so we
2895 * do an early lockdep release here:
2897 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2898 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2901 /* Here we just switch the register state and the stack. */
2902 switch_to(prev
, next
, prev
);
2906 * this_rq must be evaluated again because prev may have moved
2907 * CPUs since it called schedule(), thus the 'rq' on its stack
2908 * frame will be invalid.
2910 finish_task_switch(this_rq(), prev
);
2914 * nr_running, nr_uninterruptible and nr_context_switches:
2916 * externally visible scheduler statistics: current number of runnable
2917 * threads, current number of uninterruptible-sleeping threads, total
2918 * number of context switches performed since bootup.
2920 unsigned long nr_running(void)
2922 unsigned long i
, sum
= 0;
2924 for_each_online_cpu(i
)
2925 sum
+= cpu_rq(i
)->nr_running
;
2930 unsigned long nr_uninterruptible(void)
2932 unsigned long i
, sum
= 0;
2934 for_each_possible_cpu(i
)
2935 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2938 * Since we read the counters lockless, it might be slightly
2939 * inaccurate. Do not allow it to go below zero though:
2941 if (unlikely((long)sum
< 0))
2947 unsigned long long nr_context_switches(void)
2950 unsigned long long sum
= 0;
2952 for_each_possible_cpu(i
)
2953 sum
+= cpu_rq(i
)->nr_switches
;
2958 unsigned long nr_iowait(void)
2960 unsigned long i
, sum
= 0;
2962 for_each_possible_cpu(i
)
2963 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2968 /* Variables and functions for calc_load */
2969 static atomic_long_t calc_load_tasks
;
2970 static unsigned long calc_load_update
;
2971 unsigned long avenrun
[3];
2972 EXPORT_SYMBOL(avenrun
);
2975 * get_avenrun - get the load average array
2976 * @loads: pointer to dest load array
2977 * @offset: offset to add
2978 * @shift: shift count to shift the result left
2980 * These values are estimates at best, so no need for locking.
2982 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
2984 loads
[0] = (avenrun
[0] + offset
) << shift
;
2985 loads
[1] = (avenrun
[1] + offset
) << shift
;
2986 loads
[2] = (avenrun
[2] + offset
) << shift
;
2989 static unsigned long
2990 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
2993 load
+= active
* (FIXED_1
- exp
);
2994 return load
>> FSHIFT
;
2998 * calc_load - update the avenrun load estimates 10 ticks after the
2999 * CPUs have updated calc_load_tasks.
3001 void calc_global_load(void)
3003 unsigned long upd
= calc_load_update
+ 10;
3006 if (time_before(jiffies
, upd
))
3009 active
= atomic_long_read(&calc_load_tasks
);
3010 active
= active
> 0 ? active
* FIXED_1
: 0;
3012 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
3013 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
3014 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
3016 calc_load_update
+= LOAD_FREQ
;
3020 * Either called from update_cpu_load() or from a cpu going idle
3022 static void calc_load_account_active(struct rq
*this_rq
)
3024 long nr_active
, delta
;
3026 nr_active
= this_rq
->nr_running
;
3027 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3029 if (nr_active
!= this_rq
->calc_load_active
) {
3030 delta
= nr_active
- this_rq
->calc_load_active
;
3031 this_rq
->calc_load_active
= nr_active
;
3032 atomic_long_add(delta
, &calc_load_tasks
);
3037 * Externally visible per-cpu scheduler statistics:
3038 * cpu_nr_migrations(cpu) - number of migrations into that cpu
3040 u64
cpu_nr_migrations(int cpu
)
3042 return cpu_rq(cpu
)->nr_migrations_in
;
3046 * Update rq->cpu_load[] statistics. This function is usually called every
3047 * scheduler tick (TICK_NSEC).
3049 static void update_cpu_load(struct rq
*this_rq
)
3051 unsigned long this_load
= this_rq
->load
.weight
;
3054 this_rq
->nr_load_updates
++;
3056 /* Update our load: */
3057 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3058 unsigned long old_load
, new_load
;
3060 /* scale is effectively 1 << i now, and >> i divides by scale */
3062 old_load
= this_rq
->cpu_load
[i
];
3063 new_load
= this_load
;
3065 * Round up the averaging division if load is increasing. This
3066 * prevents us from getting stuck on 9 if the load is 10, for
3069 if (new_load
> old_load
)
3070 new_load
+= scale
-1;
3071 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
3074 if (time_after_eq(jiffies
, this_rq
->calc_load_update
)) {
3075 this_rq
->calc_load_update
+= LOAD_FREQ
;
3076 calc_load_account_active(this_rq
);
3083 * double_rq_lock - safely lock two runqueues
3085 * Note this does not disable interrupts like task_rq_lock,
3086 * you need to do so manually before calling.
3088 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
3089 __acquires(rq1
->lock
)
3090 __acquires(rq2
->lock
)
3092 BUG_ON(!irqs_disabled());
3094 spin_lock(&rq1
->lock
);
3095 __acquire(rq2
->lock
); /* Fake it out ;) */
3098 spin_lock(&rq1
->lock
);
3099 spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
3101 spin_lock(&rq2
->lock
);
3102 spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
3105 update_rq_clock(rq1
);
3106 update_rq_clock(rq2
);
3110 * double_rq_unlock - safely unlock two runqueues
3112 * Note this does not restore interrupts like task_rq_unlock,
3113 * you need to do so manually after calling.
3115 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
3116 __releases(rq1
->lock
)
3117 __releases(rq2
->lock
)
3119 spin_unlock(&rq1
->lock
);
3121 spin_unlock(&rq2
->lock
);
3123 __release(rq2
->lock
);
3127 * If dest_cpu is allowed for this process, migrate the task to it.
3128 * This is accomplished by forcing the cpu_allowed mask to only
3129 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
3130 * the cpu_allowed mask is restored.
3132 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
3134 struct migration_req req
;
3135 unsigned long flags
;
3138 rq
= task_rq_lock(p
, &flags
);
3139 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
3140 || unlikely(!cpu_active(dest_cpu
)))
3143 /* force the process onto the specified CPU */
3144 if (migrate_task(p
, dest_cpu
, &req
)) {
3145 /* Need to wait for migration thread (might exit: take ref). */
3146 struct task_struct
*mt
= rq
->migration_thread
;
3148 get_task_struct(mt
);
3149 task_rq_unlock(rq
, &flags
);
3150 wake_up_process(mt
);
3151 put_task_struct(mt
);
3152 wait_for_completion(&req
.done
);
3157 task_rq_unlock(rq
, &flags
);
3161 * sched_exec - execve() is a valuable balancing opportunity, because at
3162 * this point the task has the smallest effective memory and cache footprint.
3164 void sched_exec(void)
3166 int new_cpu
, this_cpu
= get_cpu();
3167 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
3169 if (new_cpu
!= this_cpu
)
3170 sched_migrate_task(current
, new_cpu
);
3174 * pull_task - move a task from a remote runqueue to the local runqueue.
3175 * Both runqueues must be locked.
3177 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
3178 struct rq
*this_rq
, int this_cpu
)
3180 deactivate_task(src_rq
, p
, 0);
3181 set_task_cpu(p
, this_cpu
);
3182 activate_task(this_rq
, p
, 0);
3184 * Note that idle threads have a prio of MAX_PRIO, for this test
3185 * to be always true for them.
3187 check_preempt_curr(this_rq
, p
, 0);
3191 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3194 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
3195 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3198 int tsk_cache_hot
= 0;
3200 * We do not migrate tasks that are:
3201 * 1) running (obviously), or
3202 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3203 * 3) are cache-hot on their current CPU.
3205 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
3206 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3211 if (task_running(rq
, p
)) {
3212 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3217 * Aggressive migration if:
3218 * 1) task is cache cold, or
3219 * 2) too many balance attempts have failed.
3222 tsk_cache_hot
= task_hot(p
, rq
->clock
, sd
);
3223 if (!tsk_cache_hot
||
3224 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3225 #ifdef CONFIG_SCHEDSTATS
3226 if (tsk_cache_hot
) {
3227 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3228 schedstat_inc(p
, se
.nr_forced_migrations
);
3234 if (tsk_cache_hot
) {
3235 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3241 static unsigned long
3242 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3243 unsigned long max_load_move
, struct sched_domain
*sd
,
3244 enum cpu_idle_type idle
, int *all_pinned
,
3245 int *this_best_prio
, struct rq_iterator
*iterator
)
3247 int loops
= 0, pulled
= 0, pinned
= 0;
3248 struct task_struct
*p
;
3249 long rem_load_move
= max_load_move
;
3251 if (max_load_move
== 0)
3257 * Start the load-balancing iterator:
3259 p
= iterator
->start(iterator
->arg
);
3261 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3264 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3265 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3266 p
= iterator
->next(iterator
->arg
);
3270 pull_task(busiest
, p
, this_rq
, this_cpu
);
3272 rem_load_move
-= p
->se
.load
.weight
;
3274 #ifdef CONFIG_PREEMPT
3276 * NEWIDLE balancing is a source of latency, so preemptible kernels
3277 * will stop after the first task is pulled to minimize the critical
3280 if (idle
== CPU_NEWLY_IDLE
)
3285 * We only want to steal up to the prescribed amount of weighted load.
3287 if (rem_load_move
> 0) {
3288 if (p
->prio
< *this_best_prio
)
3289 *this_best_prio
= p
->prio
;
3290 p
= iterator
->next(iterator
->arg
);
3295 * Right now, this is one of only two places pull_task() is called,
3296 * so we can safely collect pull_task() stats here rather than
3297 * inside pull_task().
3299 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3302 *all_pinned
= pinned
;
3304 return max_load_move
- rem_load_move
;
3308 * move_tasks tries to move up to max_load_move weighted load from busiest to
3309 * this_rq, as part of a balancing operation within domain "sd".
3310 * Returns 1 if successful and 0 otherwise.
3312 * Called with both runqueues locked.
3314 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3315 unsigned long max_load_move
,
3316 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3319 const struct sched_class
*class = sched_class_highest
;
3320 unsigned long total_load_moved
= 0;
3321 int this_best_prio
= this_rq
->curr
->prio
;
3325 class->load_balance(this_rq
, this_cpu
, busiest
,
3326 max_load_move
- total_load_moved
,
3327 sd
, idle
, all_pinned
, &this_best_prio
);
3328 class = class->next
;
3330 #ifdef CONFIG_PREEMPT
3332 * NEWIDLE balancing is a source of latency, so preemptible
3333 * kernels will stop after the first task is pulled to minimize
3334 * the critical section.
3336 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3339 } while (class && max_load_move
> total_load_moved
);
3341 return total_load_moved
> 0;
3345 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3346 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3347 struct rq_iterator
*iterator
)
3349 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3353 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3354 pull_task(busiest
, p
, this_rq
, this_cpu
);
3356 * Right now, this is only the second place pull_task()
3357 * is called, so we can safely collect pull_task()
3358 * stats here rather than inside pull_task().
3360 schedstat_inc(sd
, lb_gained
[idle
]);
3364 p
= iterator
->next(iterator
->arg
);
3371 * move_one_task tries to move exactly one task from busiest to this_rq, as
3372 * part of active balancing operations within "domain".
3373 * Returns 1 if successful and 0 otherwise.
3375 * Called with both runqueues locked.
3377 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3378 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3380 const struct sched_class
*class;
3382 for (class = sched_class_highest
; class; class = class->next
)
3383 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3388 /********** Helpers for find_busiest_group ************************/
3390 * sd_lb_stats - Structure to store the statistics of a sched_domain
3391 * during load balancing.
3393 struct sd_lb_stats
{
3394 struct sched_group
*busiest
; /* Busiest group in this sd */
3395 struct sched_group
*this; /* Local group in this sd */
3396 unsigned long total_load
; /* Total load of all groups in sd */
3397 unsigned long total_pwr
; /* Total power of all groups in sd */
3398 unsigned long avg_load
; /* Average load across all groups in sd */
3400 /** Statistics of this group */
3401 unsigned long this_load
;
3402 unsigned long this_load_per_task
;
3403 unsigned long this_nr_running
;
3405 /* Statistics of the busiest group */
3406 unsigned long max_load
;
3407 unsigned long busiest_load_per_task
;
3408 unsigned long busiest_nr_running
;
3410 int group_imb
; /* Is there imbalance in this sd */
3411 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3412 int power_savings_balance
; /* Is powersave balance needed for this sd */
3413 struct sched_group
*group_min
; /* Least loaded group in sd */
3414 struct sched_group
*group_leader
; /* Group which relieves group_min */
3415 unsigned long min_load_per_task
; /* load_per_task in group_min */
3416 unsigned long leader_nr_running
; /* Nr running of group_leader */
3417 unsigned long min_nr_running
; /* Nr running of group_min */
3422 * sg_lb_stats - stats of a sched_group required for load_balancing
3424 struct sg_lb_stats
{
3425 unsigned long avg_load
; /*Avg load across the CPUs of the group */
3426 unsigned long group_load
; /* Total load over the CPUs of the group */
3427 unsigned long sum_nr_running
; /* Nr tasks running in the group */
3428 unsigned long sum_weighted_load
; /* Weighted load of group's tasks */
3429 unsigned long group_capacity
;
3430 int group_imb
; /* Is there an imbalance in the group ? */
3434 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3435 * @group: The group whose first cpu is to be returned.
3437 static inline unsigned int group_first_cpu(struct sched_group
*group
)
3439 return cpumask_first(sched_group_cpus(group
));
3443 * get_sd_load_idx - Obtain the load index for a given sched domain.
3444 * @sd: The sched_domain whose load_idx is to be obtained.
3445 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3447 static inline int get_sd_load_idx(struct sched_domain
*sd
,
3448 enum cpu_idle_type idle
)
3454 load_idx
= sd
->busy_idx
;
3457 case CPU_NEWLY_IDLE
:
3458 load_idx
= sd
->newidle_idx
;
3461 load_idx
= sd
->idle_idx
;
3469 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3471 * init_sd_power_savings_stats - Initialize power savings statistics for
3472 * the given sched_domain, during load balancing.
3474 * @sd: Sched domain whose power-savings statistics are to be initialized.
3475 * @sds: Variable containing the statistics for sd.
3476 * @idle: Idle status of the CPU at which we're performing load-balancing.
3478 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3479 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3482 * Busy processors will not participate in power savings
3485 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3486 sds
->power_savings_balance
= 0;
3488 sds
->power_savings_balance
= 1;
3489 sds
->min_nr_running
= ULONG_MAX
;
3490 sds
->leader_nr_running
= 0;
3495 * update_sd_power_savings_stats - Update the power saving stats for a
3496 * sched_domain while performing load balancing.
3498 * @group: sched_group belonging to the sched_domain under consideration.
3499 * @sds: Variable containing the statistics of the sched_domain
3500 * @local_group: Does group contain the CPU for which we're performing
3502 * @sgs: Variable containing the statistics of the group.
3504 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3505 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3508 if (!sds
->power_savings_balance
)
3512 * If the local group is idle or completely loaded
3513 * no need to do power savings balance at this domain
3515 if (local_group
&& (sds
->this_nr_running
>= sgs
->group_capacity
||
3516 !sds
->this_nr_running
))
3517 sds
->power_savings_balance
= 0;
3520 * If a group is already running at full capacity or idle,
3521 * don't include that group in power savings calculations
3523 if (!sds
->power_savings_balance
||
3524 sgs
->sum_nr_running
>= sgs
->group_capacity
||
3525 !sgs
->sum_nr_running
)
3529 * Calculate the group which has the least non-idle load.
3530 * This is the group from where we need to pick up the load
3533 if ((sgs
->sum_nr_running
< sds
->min_nr_running
) ||
3534 (sgs
->sum_nr_running
== sds
->min_nr_running
&&
3535 group_first_cpu(group
) > group_first_cpu(sds
->group_min
))) {
3536 sds
->group_min
= group
;
3537 sds
->min_nr_running
= sgs
->sum_nr_running
;
3538 sds
->min_load_per_task
= sgs
->sum_weighted_load
/
3539 sgs
->sum_nr_running
;
3543 * Calculate the group which is almost near its
3544 * capacity but still has some space to pick up some load
3545 * from other group and save more power
3547 if (sgs
->sum_nr_running
> sgs
->group_capacity
- 1)
3550 if (sgs
->sum_nr_running
> sds
->leader_nr_running
||
3551 (sgs
->sum_nr_running
== sds
->leader_nr_running
&&
3552 group_first_cpu(group
) < group_first_cpu(sds
->group_leader
))) {
3553 sds
->group_leader
= group
;
3554 sds
->leader_nr_running
= sgs
->sum_nr_running
;
3559 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3560 * @sds: Variable containing the statistics of the sched_domain
3561 * under consideration.
3562 * @this_cpu: Cpu at which we're currently performing load-balancing.
3563 * @imbalance: Variable to store the imbalance.
3566 * Check if we have potential to perform some power-savings balance.
3567 * If yes, set the busiest group to be the least loaded group in the
3568 * sched_domain, so that it's CPUs can be put to idle.
3570 * Returns 1 if there is potential to perform power-savings balance.
3573 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3574 int this_cpu
, unsigned long *imbalance
)
3576 if (!sds
->power_savings_balance
)
3579 if (sds
->this != sds
->group_leader
||
3580 sds
->group_leader
== sds
->group_min
)
3583 *imbalance
= sds
->min_load_per_task
;
3584 sds
->busiest
= sds
->group_min
;
3586 if (sched_mc_power_savings
>= POWERSAVINGS_BALANCE_WAKEUP
) {
3587 cpu_rq(this_cpu
)->rd
->sched_mc_preferred_wakeup_cpu
=
3588 group_first_cpu(sds
->group_leader
);
3594 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3595 static inline void init_sd_power_savings_stats(struct sched_domain
*sd
,
3596 struct sd_lb_stats
*sds
, enum cpu_idle_type idle
)
3601 static inline void update_sd_power_savings_stats(struct sched_group
*group
,
3602 struct sd_lb_stats
*sds
, int local_group
, struct sg_lb_stats
*sgs
)
3607 static inline int check_power_save_busiest_group(struct sd_lb_stats
*sds
,
3608 int this_cpu
, unsigned long *imbalance
)
3612 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3616 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3617 * @group: sched_group whose statistics are to be updated.
3618 * @this_cpu: Cpu for which load balance is currently performed.
3619 * @idle: Idle status of this_cpu
3620 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3621 * @sd_idle: Idle status of the sched_domain containing group.
3622 * @local_group: Does group contain this_cpu.
3623 * @cpus: Set of cpus considered for load balancing.
3624 * @balance: Should we balance.
3625 * @sgs: variable to hold the statistics for this group.
3627 static inline void update_sg_lb_stats(struct sched_group
*group
, int this_cpu
,
3628 enum cpu_idle_type idle
, int load_idx
, int *sd_idle
,
3629 int local_group
, const struct cpumask
*cpus
,
3630 int *balance
, struct sg_lb_stats
*sgs
)
3632 unsigned long load
, max_cpu_load
, min_cpu_load
;
3634 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3635 unsigned long sum_avg_load_per_task
;
3636 unsigned long avg_load_per_task
;
3639 balance_cpu
= group_first_cpu(group
);
3641 /* Tally up the load of all CPUs in the group */
3642 sum_avg_load_per_task
= avg_load_per_task
= 0;
3644 min_cpu_load
= ~0UL;
3646 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3647 struct rq
*rq
= cpu_rq(i
);
3649 if (*sd_idle
&& rq
->nr_running
)
3652 /* Bias balancing toward cpus of our domain */
3654 if (idle_cpu(i
) && !first_idle_cpu
) {
3659 load
= target_load(i
, load_idx
);
3661 load
= source_load(i
, load_idx
);
3662 if (load
> max_cpu_load
)
3663 max_cpu_load
= load
;
3664 if (min_cpu_load
> load
)
3665 min_cpu_load
= load
;
3668 sgs
->group_load
+= load
;
3669 sgs
->sum_nr_running
+= rq
->nr_running
;
3670 sgs
->sum_weighted_load
+= weighted_cpuload(i
);
3672 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3676 * First idle cpu or the first cpu(busiest) in this sched group
3677 * is eligible for doing load balancing at this and above
3678 * domains. In the newly idle case, we will allow all the cpu's
3679 * to do the newly idle load balance.
3681 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3682 balance_cpu
!= this_cpu
&& balance
) {
3687 /* Adjust by relative CPU power of the group */
3688 sgs
->avg_load
= sg_div_cpu_power(group
,
3689 sgs
->group_load
* SCHED_LOAD_SCALE
);
3693 * Consider the group unbalanced when the imbalance is larger
3694 * than the average weight of two tasks.
3696 * APZ: with cgroup the avg task weight can vary wildly and
3697 * might not be a suitable number - should we keep a
3698 * normalized nr_running number somewhere that negates
3701 avg_load_per_task
= sg_div_cpu_power(group
,
3702 sum_avg_load_per_task
* SCHED_LOAD_SCALE
);
3704 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3707 sgs
->group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3712 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3713 * @sd: sched_domain whose statistics are to be updated.
3714 * @this_cpu: Cpu for which load balance is currently performed.
3715 * @idle: Idle status of this_cpu
3716 * @sd_idle: Idle status of the sched_domain containing group.
3717 * @cpus: Set of cpus considered for load balancing.
3718 * @balance: Should we balance.
3719 * @sds: variable to hold the statistics for this sched_domain.
3721 static inline void update_sd_lb_stats(struct sched_domain
*sd
, int this_cpu
,
3722 enum cpu_idle_type idle
, int *sd_idle
,
3723 const struct cpumask
*cpus
, int *balance
,
3724 struct sd_lb_stats
*sds
)
3726 struct sched_group
*group
= sd
->groups
;
3727 struct sg_lb_stats sgs
;
3730 init_sd_power_savings_stats(sd
, sds
, idle
);
3731 load_idx
= get_sd_load_idx(sd
, idle
);
3736 local_group
= cpumask_test_cpu(this_cpu
,
3737 sched_group_cpus(group
));
3738 memset(&sgs
, 0, sizeof(sgs
));
3739 update_sg_lb_stats(group
, this_cpu
, idle
, load_idx
, sd_idle
,
3740 local_group
, cpus
, balance
, &sgs
);
3742 if (local_group
&& balance
&& !(*balance
))
3745 sds
->total_load
+= sgs
.group_load
;
3746 sds
->total_pwr
+= group
->__cpu_power
;
3749 sds
->this_load
= sgs
.avg_load
;
3751 sds
->this_nr_running
= sgs
.sum_nr_running
;
3752 sds
->this_load_per_task
= sgs
.sum_weighted_load
;
3753 } else if (sgs
.avg_load
> sds
->max_load
&&
3754 (sgs
.sum_nr_running
> sgs
.group_capacity
||
3756 sds
->max_load
= sgs
.avg_load
;
3757 sds
->busiest
= group
;
3758 sds
->busiest_nr_running
= sgs
.sum_nr_running
;
3759 sds
->busiest_load_per_task
= sgs
.sum_weighted_load
;
3760 sds
->group_imb
= sgs
.group_imb
;
3763 update_sd_power_savings_stats(group
, sds
, local_group
, &sgs
);
3764 group
= group
->next
;
3765 } while (group
!= sd
->groups
);
3770 * fix_small_imbalance - Calculate the minor imbalance that exists
3771 * amongst the groups of a sched_domain, during
3773 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3774 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3775 * @imbalance: Variable to store the imbalance.
3777 static inline void fix_small_imbalance(struct sd_lb_stats
*sds
,
3778 int this_cpu
, unsigned long *imbalance
)
3780 unsigned long tmp
, pwr_now
= 0, pwr_move
= 0;
3781 unsigned int imbn
= 2;
3783 if (sds
->this_nr_running
) {
3784 sds
->this_load_per_task
/= sds
->this_nr_running
;
3785 if (sds
->busiest_load_per_task
>
3786 sds
->this_load_per_task
)
3789 sds
->this_load_per_task
=
3790 cpu_avg_load_per_task(this_cpu
);
3792 if (sds
->max_load
- sds
->this_load
+ sds
->busiest_load_per_task
>=
3793 sds
->busiest_load_per_task
* imbn
) {
3794 *imbalance
= sds
->busiest_load_per_task
;
3799 * OK, we don't have enough imbalance to justify moving tasks,
3800 * however we may be able to increase total CPU power used by
3804 pwr_now
+= sds
->busiest
->__cpu_power
*
3805 min(sds
->busiest_load_per_task
, sds
->max_load
);
3806 pwr_now
+= sds
->this->__cpu_power
*
3807 min(sds
->this_load_per_task
, sds
->this_load
);
3808 pwr_now
/= SCHED_LOAD_SCALE
;
3810 /* Amount of load we'd subtract */
3811 tmp
= sg_div_cpu_power(sds
->busiest
,
3812 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
);
3813 if (sds
->max_load
> tmp
)
3814 pwr_move
+= sds
->busiest
->__cpu_power
*
3815 min(sds
->busiest_load_per_task
, sds
->max_load
- tmp
);
3817 /* Amount of load we'd add */
3818 if (sds
->max_load
* sds
->busiest
->__cpu_power
<
3819 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
)
3820 tmp
= sg_div_cpu_power(sds
->this,
3821 sds
->max_load
* sds
->busiest
->__cpu_power
);
3823 tmp
= sg_div_cpu_power(sds
->this,
3824 sds
->busiest_load_per_task
* SCHED_LOAD_SCALE
);
3825 pwr_move
+= sds
->this->__cpu_power
*
3826 min(sds
->this_load_per_task
, sds
->this_load
+ tmp
);
3827 pwr_move
/= SCHED_LOAD_SCALE
;
3829 /* Move if we gain throughput */
3830 if (pwr_move
> pwr_now
)
3831 *imbalance
= sds
->busiest_load_per_task
;
3835 * calculate_imbalance - Calculate the amount of imbalance present within the
3836 * groups of a given sched_domain during load balance.
3837 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3838 * @this_cpu: Cpu for which currently load balance is being performed.
3839 * @imbalance: The variable to store the imbalance.
3841 static inline void calculate_imbalance(struct sd_lb_stats
*sds
, int this_cpu
,
3842 unsigned long *imbalance
)
3844 unsigned long max_pull
;
3846 * In the presence of smp nice balancing, certain scenarios can have
3847 * max load less than avg load(as we skip the groups at or below
3848 * its cpu_power, while calculating max_load..)
3850 if (sds
->max_load
< sds
->avg_load
) {
3852 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3855 /* Don't want to pull so many tasks that a group would go idle */
3856 max_pull
= min(sds
->max_load
- sds
->avg_load
,
3857 sds
->max_load
- sds
->busiest_load_per_task
);
3859 /* How much load to actually move to equalise the imbalance */
3860 *imbalance
= min(max_pull
* sds
->busiest
->__cpu_power
,
3861 (sds
->avg_load
- sds
->this_load
) * sds
->this->__cpu_power
)
3865 * if *imbalance is less than the average load per runnable task
3866 * there is no gaurantee that any tasks will be moved so we'll have
3867 * a think about bumping its value to force at least one task to be
3870 if (*imbalance
< sds
->busiest_load_per_task
)
3871 return fix_small_imbalance(sds
, this_cpu
, imbalance
);
3874 /******* find_busiest_group() helpers end here *********************/
3877 * find_busiest_group - Returns the busiest group within the sched_domain
3878 * if there is an imbalance. If there isn't an imbalance, and
3879 * the user has opted for power-savings, it returns a group whose
3880 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3881 * such a group exists.
3883 * Also calculates the amount of weighted load which should be moved
3884 * to restore balance.
3886 * @sd: The sched_domain whose busiest group is to be returned.
3887 * @this_cpu: The cpu for which load balancing is currently being performed.
3888 * @imbalance: Variable which stores amount of weighted load which should
3889 * be moved to restore balance/put a group to idle.
3890 * @idle: The idle status of this_cpu.
3891 * @sd_idle: The idleness of sd
3892 * @cpus: The set of CPUs under consideration for load-balancing.
3893 * @balance: Pointer to a variable indicating if this_cpu
3894 * is the appropriate cpu to perform load balancing at this_level.
3896 * Returns: - the busiest group if imbalance exists.
3897 * - If no imbalance and user has opted for power-savings balance,
3898 * return the least loaded group whose CPUs can be
3899 * put to idle by rebalancing its tasks onto our group.
3901 static struct sched_group
*
3902 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3903 unsigned long *imbalance
, enum cpu_idle_type idle
,
3904 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
3906 struct sd_lb_stats sds
;
3908 memset(&sds
, 0, sizeof(sds
));
3911 * Compute the various statistics relavent for load balancing at
3914 update_sd_lb_stats(sd
, this_cpu
, idle
, sd_idle
, cpus
,
3917 /* Cases where imbalance does not exist from POV of this_cpu */
3918 /* 1) this_cpu is not the appropriate cpu to perform load balancing
3920 * 2) There is no busy sibling group to pull from.
3921 * 3) This group is the busiest group.
3922 * 4) This group is more busy than the avg busieness at this
3924 * 5) The imbalance is within the specified limit.
3925 * 6) Any rebalance would lead to ping-pong
3927 if (balance
&& !(*balance
))
3930 if (!sds
.busiest
|| sds
.busiest_nr_running
== 0)
3933 if (sds
.this_load
>= sds
.max_load
)
3936 sds
.avg_load
= (SCHED_LOAD_SCALE
* sds
.total_load
) / sds
.total_pwr
;
3938 if (sds
.this_load
>= sds
.avg_load
)
3941 if (100 * sds
.max_load
<= sd
->imbalance_pct
* sds
.this_load
)
3944 sds
.busiest_load_per_task
/= sds
.busiest_nr_running
;
3946 sds
.busiest_load_per_task
=
3947 min(sds
.busiest_load_per_task
, sds
.avg_load
);
3950 * We're trying to get all the cpus to the average_load, so we don't
3951 * want to push ourselves above the average load, nor do we wish to
3952 * reduce the max loaded cpu below the average load, as either of these
3953 * actions would just result in more rebalancing later, and ping-pong
3954 * tasks around. Thus we look for the minimum possible imbalance.
3955 * Negative imbalances (*we* are more loaded than anyone else) will
3956 * be counted as no imbalance for these purposes -- we can't fix that
3957 * by pulling tasks to us. Be careful of negative numbers as they'll
3958 * appear as very large values with unsigned longs.
3960 if (sds
.max_load
<= sds
.busiest_load_per_task
)
3963 /* Looks like there is an imbalance. Compute it */
3964 calculate_imbalance(&sds
, this_cpu
, imbalance
);
3969 * There is no obvious imbalance. But check if we can do some balancing
3972 if (check_power_save_busiest_group(&sds
, this_cpu
, imbalance
))
3980 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3983 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3984 unsigned long imbalance
, const struct cpumask
*cpus
)
3986 struct rq
*busiest
= NULL
, *rq
;
3987 unsigned long max_load
= 0;
3990 for_each_cpu(i
, sched_group_cpus(group
)) {
3993 if (!cpumask_test_cpu(i
, cpus
))
3997 wl
= weighted_cpuload(i
);
3999 if (rq
->nr_running
== 1 && wl
> imbalance
)
4002 if (wl
> max_load
) {
4012 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
4013 * so long as it is large enough.
4015 #define MAX_PINNED_INTERVAL 512
4017 /* Working cpumask for load_balance and load_balance_newidle. */
4018 static DEFINE_PER_CPU(cpumask_var_t
, load_balance_tmpmask
);
4021 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4022 * tasks if there is an imbalance.
4024 static int load_balance(int this_cpu
, struct rq
*this_rq
,
4025 struct sched_domain
*sd
, enum cpu_idle_type idle
,
4028 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
4029 struct sched_group
*group
;
4030 unsigned long imbalance
;
4032 unsigned long flags
;
4033 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4035 cpumask_setall(cpus
);
4038 * When power savings policy is enabled for the parent domain, idle
4039 * sibling can pick up load irrespective of busy siblings. In this case,
4040 * let the state of idle sibling percolate up as CPU_IDLE, instead of
4041 * portraying it as CPU_NOT_IDLE.
4043 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4044 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4047 schedstat_inc(sd
, lb_count
[idle
]);
4051 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
4058 schedstat_inc(sd
, lb_nobusyg
[idle
]);
4062 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
4064 schedstat_inc(sd
, lb_nobusyq
[idle
]);
4068 BUG_ON(busiest
== this_rq
);
4070 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
4073 if (busiest
->nr_running
> 1) {
4075 * Attempt to move tasks. If find_busiest_group has found
4076 * an imbalance but busiest->nr_running <= 1, the group is
4077 * still unbalanced. ld_moved simply stays zero, so it is
4078 * correctly treated as an imbalance.
4080 local_irq_save(flags
);
4081 double_rq_lock(this_rq
, busiest
);
4082 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4083 imbalance
, sd
, idle
, &all_pinned
);
4084 double_rq_unlock(this_rq
, busiest
);
4085 local_irq_restore(flags
);
4088 * some other cpu did the load balance for us.
4090 if (ld_moved
&& this_cpu
!= smp_processor_id())
4091 resched_cpu(this_cpu
);
4093 /* All tasks on this runqueue were pinned by CPU affinity */
4094 if (unlikely(all_pinned
)) {
4095 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4096 if (!cpumask_empty(cpus
))
4103 schedstat_inc(sd
, lb_failed
[idle
]);
4104 sd
->nr_balance_failed
++;
4106 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
4108 spin_lock_irqsave(&busiest
->lock
, flags
);
4110 /* don't kick the migration_thread, if the curr
4111 * task on busiest cpu can't be moved to this_cpu
4113 if (!cpumask_test_cpu(this_cpu
,
4114 &busiest
->curr
->cpus_allowed
)) {
4115 spin_unlock_irqrestore(&busiest
->lock
, flags
);
4117 goto out_one_pinned
;
4120 if (!busiest
->active_balance
) {
4121 busiest
->active_balance
= 1;
4122 busiest
->push_cpu
= this_cpu
;
4125 spin_unlock_irqrestore(&busiest
->lock
, flags
);
4127 wake_up_process(busiest
->migration_thread
);
4130 * We've kicked active balancing, reset the failure
4133 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
4136 sd
->nr_balance_failed
= 0;
4138 if (likely(!active_balance
)) {
4139 /* We were unbalanced, so reset the balancing interval */
4140 sd
->balance_interval
= sd
->min_interval
;
4143 * If we've begun active balancing, start to back off. This
4144 * case may not be covered by the all_pinned logic if there
4145 * is only 1 task on the busy runqueue (because we don't call
4148 if (sd
->balance_interval
< sd
->max_interval
)
4149 sd
->balance_interval
*= 2;
4152 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4153 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4159 schedstat_inc(sd
, lb_balanced
[idle
]);
4161 sd
->nr_balance_failed
= 0;
4164 /* tune up the balancing interval */
4165 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
4166 (sd
->balance_interval
< sd
->max_interval
))
4167 sd
->balance_interval
*= 2;
4169 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4170 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4181 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4182 * tasks if there is an imbalance.
4184 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4185 * this_rq is locked.
4188 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
)
4190 struct sched_group
*group
;
4191 struct rq
*busiest
= NULL
;
4192 unsigned long imbalance
;
4196 struct cpumask
*cpus
= __get_cpu_var(load_balance_tmpmask
);
4198 cpumask_setall(cpus
);
4201 * When power savings policy is enabled for the parent domain, idle
4202 * sibling can pick up load irrespective of busy siblings. In this case,
4203 * let the state of idle sibling percolate up as IDLE, instead of
4204 * portraying it as CPU_NOT_IDLE.
4206 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
4207 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4210 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
4212 update_shares_locked(this_rq
, sd
);
4213 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
4214 &sd_idle
, cpus
, NULL
);
4216 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
4220 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
4222 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
4226 BUG_ON(busiest
== this_rq
);
4228 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
4231 if (busiest
->nr_running
> 1) {
4232 /* Attempt to move tasks */
4233 double_lock_balance(this_rq
, busiest
);
4234 /* this_rq->clock is already updated */
4235 update_rq_clock(busiest
);
4236 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
4237 imbalance
, sd
, CPU_NEWLY_IDLE
,
4239 double_unlock_balance(this_rq
, busiest
);
4241 if (unlikely(all_pinned
)) {
4242 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
4243 if (!cpumask_empty(cpus
))
4249 int active_balance
= 0;
4251 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
4252 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4253 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4256 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
4259 if (sd
->nr_balance_failed
++ < 2)
4263 * The only task running in a non-idle cpu can be moved to this
4264 * cpu in an attempt to completely freeup the other CPU
4265 * package. The same method used to move task in load_balance()
4266 * have been extended for load_balance_newidle() to speedup
4267 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4269 * The package power saving logic comes from
4270 * find_busiest_group(). If there are no imbalance, then
4271 * f_b_g() will return NULL. However when sched_mc={1,2} then
4272 * f_b_g() will select a group from which a running task may be
4273 * pulled to this cpu in order to make the other package idle.
4274 * If there is no opportunity to make a package idle and if
4275 * there are no imbalance, then f_b_g() will return NULL and no
4276 * action will be taken in load_balance_newidle().
4278 * Under normal task pull operation due to imbalance, there
4279 * will be more than one task in the source run queue and
4280 * move_tasks() will succeed. ld_moved will be true and this
4281 * active balance code will not be triggered.
4284 /* Lock busiest in correct order while this_rq is held */
4285 double_lock_balance(this_rq
, busiest
);
4288 * don't kick the migration_thread, if the curr
4289 * task on busiest cpu can't be moved to this_cpu
4291 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
4292 double_unlock_balance(this_rq
, busiest
);
4297 if (!busiest
->active_balance
) {
4298 busiest
->active_balance
= 1;
4299 busiest
->push_cpu
= this_cpu
;
4303 double_unlock_balance(this_rq
, busiest
);
4305 * Should not call ttwu while holding a rq->lock
4307 spin_unlock(&this_rq
->lock
);
4309 wake_up_process(busiest
->migration_thread
);
4310 spin_lock(&this_rq
->lock
);
4313 sd
->nr_balance_failed
= 0;
4315 update_shares_locked(this_rq
, sd
);
4319 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
4320 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
4321 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
4323 sd
->nr_balance_failed
= 0;
4329 * idle_balance is called by schedule() if this_cpu is about to become
4330 * idle. Attempts to pull tasks from other CPUs.
4332 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
4334 struct sched_domain
*sd
;
4335 int pulled_task
= 0;
4336 unsigned long next_balance
= jiffies
+ HZ
;
4338 for_each_domain(this_cpu
, sd
) {
4339 unsigned long interval
;
4341 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4344 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
4345 /* If we've pulled tasks over stop searching: */
4346 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
4349 interval
= msecs_to_jiffies(sd
->balance_interval
);
4350 if (time_after(next_balance
, sd
->last_balance
+ interval
))
4351 next_balance
= sd
->last_balance
+ interval
;
4355 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
4357 * We are going idle. next_balance may be set based on
4358 * a busy processor. So reset next_balance.
4360 this_rq
->next_balance
= next_balance
;
4365 * active_load_balance is run by migration threads. It pushes running tasks
4366 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4367 * running on each physical CPU where possible, and avoids physical /
4368 * logical imbalances.
4370 * Called with busiest_rq locked.
4372 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
4374 int target_cpu
= busiest_rq
->push_cpu
;
4375 struct sched_domain
*sd
;
4376 struct rq
*target_rq
;
4378 /* Is there any task to move? */
4379 if (busiest_rq
->nr_running
<= 1)
4382 target_rq
= cpu_rq(target_cpu
);
4385 * This condition is "impossible", if it occurs
4386 * we need to fix it. Originally reported by
4387 * Bjorn Helgaas on a 128-cpu setup.
4389 BUG_ON(busiest_rq
== target_rq
);
4391 /* move a task from busiest_rq to target_rq */
4392 double_lock_balance(busiest_rq
, target_rq
);
4393 update_rq_clock(busiest_rq
);
4394 update_rq_clock(target_rq
);
4396 /* Search for an sd spanning us and the target CPU. */
4397 for_each_domain(target_cpu
, sd
) {
4398 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
4399 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
4404 schedstat_inc(sd
, alb_count
);
4406 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
4408 schedstat_inc(sd
, alb_pushed
);
4410 schedstat_inc(sd
, alb_failed
);
4412 double_unlock_balance(busiest_rq
, target_rq
);
4417 atomic_t load_balancer
;
4418 cpumask_var_t cpu_mask
;
4419 cpumask_var_t ilb_grp_nohz_mask
;
4420 } nohz ____cacheline_aligned
= {
4421 .load_balancer
= ATOMIC_INIT(-1),
4424 int get_nohz_load_balancer(void)
4426 return atomic_read(&nohz
.load_balancer
);
4429 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
4431 * lowest_flag_domain - Return lowest sched_domain containing flag.
4432 * @cpu: The cpu whose lowest level of sched domain is to
4434 * @flag: The flag to check for the lowest sched_domain
4435 * for the given cpu.
4437 * Returns the lowest sched_domain of a cpu which contains the given flag.
4439 static inline struct sched_domain
*lowest_flag_domain(int cpu
, int flag
)
4441 struct sched_domain
*sd
;
4443 for_each_domain(cpu
, sd
)
4444 if (sd
&& (sd
->flags
& flag
))
4451 * for_each_flag_domain - Iterates over sched_domains containing the flag.
4452 * @cpu: The cpu whose domains we're iterating over.
4453 * @sd: variable holding the value of the power_savings_sd
4455 * @flag: The flag to filter the sched_domains to be iterated.
4457 * Iterates over all the scheduler domains for a given cpu that has the 'flag'
4458 * set, starting from the lowest sched_domain to the highest.
4460 #define for_each_flag_domain(cpu, sd, flag) \
4461 for (sd = lowest_flag_domain(cpu, flag); \
4462 (sd && (sd->flags & flag)); sd = sd->parent)
4465 * is_semi_idle_group - Checks if the given sched_group is semi-idle.
4466 * @ilb_group: group to be checked for semi-idleness
4468 * Returns: 1 if the group is semi-idle. 0 otherwise.
4470 * We define a sched_group to be semi idle if it has atleast one idle-CPU
4471 * and atleast one non-idle CPU. This helper function checks if the given
4472 * sched_group is semi-idle or not.
4474 static inline int is_semi_idle_group(struct sched_group
*ilb_group
)
4476 cpumask_and(nohz
.ilb_grp_nohz_mask
, nohz
.cpu_mask
,
4477 sched_group_cpus(ilb_group
));
4480 * A sched_group is semi-idle when it has atleast one busy cpu
4481 * and atleast one idle cpu.
4483 if (cpumask_empty(nohz
.ilb_grp_nohz_mask
))
4486 if (cpumask_equal(nohz
.ilb_grp_nohz_mask
, sched_group_cpus(ilb_group
)))
4492 * find_new_ilb - Finds the optimum idle load balancer for nomination.
4493 * @cpu: The cpu which is nominating a new idle_load_balancer.
4495 * Returns: Returns the id of the idle load balancer if it exists,
4496 * Else, returns >= nr_cpu_ids.
4498 * This algorithm picks the idle load balancer such that it belongs to a
4499 * semi-idle powersavings sched_domain. The idea is to try and avoid
4500 * completely idle packages/cores just for the purpose of idle load balancing
4501 * when there are other idle cpu's which are better suited for that job.
4503 static int find_new_ilb(int cpu
)
4505 struct sched_domain
*sd
;
4506 struct sched_group
*ilb_group
;
4509 * Have idle load balancer selection from semi-idle packages only
4510 * when power-aware load balancing is enabled
4512 if (!(sched_smt_power_savings
|| sched_mc_power_savings
))
4516 * Optimize for the case when we have no idle CPUs or only one
4517 * idle CPU. Don't walk the sched_domain hierarchy in such cases
4519 if (cpumask_weight(nohz
.cpu_mask
) < 2)
4522 for_each_flag_domain(cpu
, sd
, SD_POWERSAVINGS_BALANCE
) {
4523 ilb_group
= sd
->groups
;
4526 if (is_semi_idle_group(ilb_group
))
4527 return cpumask_first(nohz
.ilb_grp_nohz_mask
);
4529 ilb_group
= ilb_group
->next
;
4531 } while (ilb_group
!= sd
->groups
);
4535 return cpumask_first(nohz
.cpu_mask
);
4537 #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
4538 static inline int find_new_ilb(int call_cpu
)
4540 return cpumask_first(nohz
.cpu_mask
);
4545 * This routine will try to nominate the ilb (idle load balancing)
4546 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4547 * load balancing on behalf of all those cpus. If all the cpus in the system
4548 * go into this tickless mode, then there will be no ilb owner (as there is
4549 * no need for one) and all the cpus will sleep till the next wakeup event
4552 * For the ilb owner, tick is not stopped. And this tick will be used
4553 * for idle load balancing. ilb owner will still be part of
4556 * While stopping the tick, this cpu will become the ilb owner if there
4557 * is no other owner. And will be the owner till that cpu becomes busy
4558 * or if all cpus in the system stop their ticks at which point
4559 * there is no need for ilb owner.
4561 * When the ilb owner becomes busy, it nominates another owner, during the
4562 * next busy scheduler_tick()
4564 int select_nohz_load_balancer(int stop_tick
)
4566 int cpu
= smp_processor_id();
4569 cpu_rq(cpu
)->in_nohz_recently
= 1;
4571 if (!cpu_active(cpu
)) {
4572 if (atomic_read(&nohz
.load_balancer
) != cpu
)
4576 * If we are going offline and still the leader,
4579 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4585 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
4587 /* time for ilb owner also to sleep */
4588 if (cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4589 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4590 atomic_set(&nohz
.load_balancer
, -1);
4594 if (atomic_read(&nohz
.load_balancer
) == -1) {
4595 /* make me the ilb owner */
4596 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4598 } else if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4601 if (!(sched_smt_power_savings
||
4602 sched_mc_power_savings
))
4605 * Check to see if there is a more power-efficient
4608 new_ilb
= find_new_ilb(cpu
);
4609 if (new_ilb
< nr_cpu_ids
&& new_ilb
!= cpu
) {
4610 atomic_set(&nohz
.load_balancer
, -1);
4611 resched_cpu(new_ilb
);
4617 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4620 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4622 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4623 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4630 static DEFINE_SPINLOCK(balancing
);
4633 * It checks each scheduling domain to see if it is due to be balanced,
4634 * and initiates a balancing operation if so.
4636 * Balancing parameters are set up in arch_init_sched_domains.
4638 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4641 struct rq
*rq
= cpu_rq(cpu
);
4642 unsigned long interval
;
4643 struct sched_domain
*sd
;
4644 /* Earliest time when we have to do rebalance again */
4645 unsigned long next_balance
= jiffies
+ 60*HZ
;
4646 int update_next_balance
= 0;
4649 for_each_domain(cpu
, sd
) {
4650 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4653 interval
= sd
->balance_interval
;
4654 if (idle
!= CPU_IDLE
)
4655 interval
*= sd
->busy_factor
;
4657 /* scale ms to jiffies */
4658 interval
= msecs_to_jiffies(interval
);
4659 if (unlikely(!interval
))
4661 if (interval
> HZ
*NR_CPUS
/10)
4662 interval
= HZ
*NR_CPUS
/10;
4664 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4666 if (need_serialize
) {
4667 if (!spin_trylock(&balancing
))
4671 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4672 if (load_balance(cpu
, rq
, sd
, idle
, &balance
)) {
4674 * We've pulled tasks over so either we're no
4675 * longer idle, or one of our SMT siblings is
4678 idle
= CPU_NOT_IDLE
;
4680 sd
->last_balance
= jiffies
;
4683 spin_unlock(&balancing
);
4685 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4686 next_balance
= sd
->last_balance
+ interval
;
4687 update_next_balance
= 1;
4691 * Stop the load balance at this level. There is another
4692 * CPU in our sched group which is doing load balancing more
4700 * next_balance will be updated only when there is a need.
4701 * When the cpu is attached to null domain for ex, it will not be
4704 if (likely(update_next_balance
))
4705 rq
->next_balance
= next_balance
;
4709 * run_rebalance_domains is triggered when needed from the scheduler tick.
4710 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4711 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4713 static void run_rebalance_domains(struct softirq_action
*h
)
4715 int this_cpu
= smp_processor_id();
4716 struct rq
*this_rq
= cpu_rq(this_cpu
);
4717 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4718 CPU_IDLE
: CPU_NOT_IDLE
;
4720 rebalance_domains(this_cpu
, idle
);
4724 * If this cpu is the owner for idle load balancing, then do the
4725 * balancing on behalf of the other idle cpus whose ticks are
4728 if (this_rq
->idle_at_tick
&&
4729 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4733 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4734 if (balance_cpu
== this_cpu
)
4738 * If this cpu gets work to do, stop the load balancing
4739 * work being done for other cpus. Next load
4740 * balancing owner will pick it up.
4745 rebalance_domains(balance_cpu
, CPU_IDLE
);
4747 rq
= cpu_rq(balance_cpu
);
4748 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4749 this_rq
->next_balance
= rq
->next_balance
;
4755 static inline int on_null_domain(int cpu
)
4757 return !rcu_dereference(cpu_rq(cpu
)->sd
);
4761 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4763 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4764 * idle load balancing owner or decide to stop the periodic load balancing,
4765 * if the whole system is idle.
4767 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4771 * If we were in the nohz mode recently and busy at the current
4772 * scheduler tick, then check if we need to nominate new idle
4775 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4776 rq
->in_nohz_recently
= 0;
4778 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4779 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4780 atomic_set(&nohz
.load_balancer
, -1);
4783 if (atomic_read(&nohz
.load_balancer
) == -1) {
4784 int ilb
= find_new_ilb(cpu
);
4786 if (ilb
< nr_cpu_ids
)
4792 * If this cpu is idle and doing idle load balancing for all the
4793 * cpus with ticks stopped, is it time for that to stop?
4795 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4796 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4802 * If this cpu is idle and the idle load balancing is done by
4803 * someone else, then no need raise the SCHED_SOFTIRQ
4805 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4806 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4809 /* Don't need to rebalance while attached to NULL domain */
4810 if (time_after_eq(jiffies
, rq
->next_balance
) &&
4811 likely(!on_null_domain(cpu
)))
4812 raise_softirq(SCHED_SOFTIRQ
);
4815 #else /* CONFIG_SMP */
4818 * on UP we do not need to balance between CPUs:
4820 static inline void idle_balance(int cpu
, struct rq
*rq
)
4826 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4828 EXPORT_PER_CPU_SYMBOL(kstat
);
4831 * Return any ns on the sched_clock that have not yet been accounted in
4832 * @p in case that task is currently running.
4834 * Called with task_rq_lock() held on @rq.
4836 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
4840 if (task_current(rq
, p
)) {
4841 update_rq_clock(rq
);
4842 ns
= rq
->clock
- p
->se
.exec_start
;
4850 unsigned long long task_delta_exec(struct task_struct
*p
)
4852 unsigned long flags
;
4856 rq
= task_rq_lock(p
, &flags
);
4857 ns
= do_task_delta_exec(p
, rq
);
4858 task_rq_unlock(rq
, &flags
);
4864 * Return accounted runtime for the task.
4865 * In case the task is currently running, return the runtime plus current's
4866 * pending runtime that have not been accounted yet.
4868 unsigned long long task_sched_runtime(struct task_struct
*p
)
4870 unsigned long flags
;
4874 rq
= task_rq_lock(p
, &flags
);
4875 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4876 task_rq_unlock(rq
, &flags
);
4882 * Return sum_exec_runtime for the thread group.
4883 * In case the task is currently running, return the sum plus current's
4884 * pending runtime that have not been accounted yet.
4886 * Note that the thread group might have other running tasks as well,
4887 * so the return value not includes other pending runtime that other
4888 * running tasks might have.
4890 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
4892 struct task_cputime totals
;
4893 unsigned long flags
;
4897 rq
= task_rq_lock(p
, &flags
);
4898 thread_group_cputime(p
, &totals
);
4899 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
4900 task_rq_unlock(rq
, &flags
);
4906 * Account user cpu time to a process.
4907 * @p: the process that the cpu time gets accounted to
4908 * @cputime: the cpu time spent in user space since the last update
4909 * @cputime_scaled: cputime scaled by cpu frequency
4911 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
4912 cputime_t cputime_scaled
)
4914 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4917 /* Add user time to process. */
4918 p
->utime
= cputime_add(p
->utime
, cputime
);
4919 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4920 account_group_user_time(p
, cputime
);
4922 /* Add user time to cpustat. */
4923 tmp
= cputime_to_cputime64(cputime
);
4924 if (TASK_NICE(p
) > 0)
4925 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
4927 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4929 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
4930 /* Account for user time used */
4931 acct_update_integrals(p
);
4935 * Account guest cpu time to a process.
4936 * @p: the process that the cpu time gets accounted to
4937 * @cputime: the cpu time spent in virtual machine since the last update
4938 * @cputime_scaled: cputime scaled by cpu frequency
4940 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
4941 cputime_t cputime_scaled
)
4944 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4946 tmp
= cputime_to_cputime64(cputime
);
4948 /* Add guest time to process. */
4949 p
->utime
= cputime_add(p
->utime
, cputime
);
4950 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4951 account_group_user_time(p
, cputime
);
4952 p
->gtime
= cputime_add(p
->gtime
, cputime
);
4954 /* Add guest time to cpustat. */
4955 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4956 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
4960 * Account system cpu time to a process.
4961 * @p: the process that the cpu time gets accounted to
4962 * @hardirq_offset: the offset to subtract from hardirq_count()
4963 * @cputime: the cpu time spent in kernel space since the last update
4964 * @cputime_scaled: cputime scaled by cpu frequency
4966 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
4967 cputime_t cputime
, cputime_t cputime_scaled
)
4969 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4972 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
4973 account_guest_time(p
, cputime
, cputime_scaled
);
4977 /* Add system time to process. */
4978 p
->stime
= cputime_add(p
->stime
, cputime
);
4979 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
4980 account_group_system_time(p
, cputime
);
4982 /* Add system time to cpustat. */
4983 tmp
= cputime_to_cputime64(cputime
);
4984 if (hardirq_count() - hardirq_offset
)
4985 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
4986 else if (softirq_count())
4987 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
4989 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
4991 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
4993 /* Account for system time used */
4994 acct_update_integrals(p
);
4998 * Account for involuntary wait time.
4999 * @steal: the cpu time spent in involuntary wait
5001 void account_steal_time(cputime_t cputime
)
5003 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5004 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5006 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
5010 * Account for idle time.
5011 * @cputime: the cpu time spent in idle wait
5013 void account_idle_time(cputime_t cputime
)
5015 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
5016 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
5017 struct rq
*rq
= this_rq();
5019 if (atomic_read(&rq
->nr_iowait
) > 0)
5020 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
5022 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
5025 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
5028 * Account a single tick of cpu time.
5029 * @p: the process that the cpu time gets accounted to
5030 * @user_tick: indicates if the tick is a user or a system tick
5032 void account_process_tick(struct task_struct
*p
, int user_tick
)
5034 cputime_t one_jiffy
= jiffies_to_cputime(1);
5035 cputime_t one_jiffy_scaled
= cputime_to_scaled(one_jiffy
);
5036 struct rq
*rq
= this_rq();
5039 account_user_time(p
, one_jiffy
, one_jiffy_scaled
);
5040 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
5041 account_system_time(p
, HARDIRQ_OFFSET
, one_jiffy
,
5044 account_idle_time(one_jiffy
);
5048 * Account multiple ticks of steal time.
5049 * @p: the process from which the cpu time has been stolen
5050 * @ticks: number of stolen ticks
5052 void account_steal_ticks(unsigned long ticks
)
5054 account_steal_time(jiffies_to_cputime(ticks
));
5058 * Account multiple ticks of idle time.
5059 * @ticks: number of stolen ticks
5061 void account_idle_ticks(unsigned long ticks
)
5063 account_idle_time(jiffies_to_cputime(ticks
));
5069 * Use precise platform statistics if available:
5071 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
5072 cputime_t
task_utime(struct task_struct
*p
)
5077 cputime_t
task_stime(struct task_struct
*p
)
5082 cputime_t
task_utime(struct task_struct
*p
)
5084 clock_t utime
= cputime_to_clock_t(p
->utime
),
5085 total
= utime
+ cputime_to_clock_t(p
->stime
);
5089 * Use CFS's precise accounting:
5091 temp
= (u64
)nsec_to_clock_t(p
->se
.sum_exec_runtime
);
5095 do_div(temp
, total
);
5097 utime
= (clock_t)temp
;
5099 p
->prev_utime
= max(p
->prev_utime
, clock_t_to_cputime(utime
));
5100 return p
->prev_utime
;
5103 cputime_t
task_stime(struct task_struct
*p
)
5108 * Use CFS's precise accounting. (we subtract utime from
5109 * the total, to make sure the total observed by userspace
5110 * grows monotonically - apps rely on that):
5112 stime
= nsec_to_clock_t(p
->se
.sum_exec_runtime
) -
5113 cputime_to_clock_t(task_utime(p
));
5116 p
->prev_stime
= max(p
->prev_stime
, clock_t_to_cputime(stime
));
5118 return p
->prev_stime
;
5122 inline cputime_t
task_gtime(struct task_struct
*p
)
5128 * This function gets called by the timer code, with HZ frequency.
5129 * We call it with interrupts disabled.
5131 * It also gets called by the fork code, when changing the parent's
5134 void scheduler_tick(void)
5136 int cpu
= smp_processor_id();
5137 struct rq
*rq
= cpu_rq(cpu
);
5138 struct task_struct
*curr
= rq
->curr
;
5142 spin_lock(&rq
->lock
);
5143 update_rq_clock(rq
);
5144 update_cpu_load(rq
);
5145 curr
->sched_class
->task_tick(rq
, curr
, 0);
5146 spin_unlock(&rq
->lock
);
5148 perf_counter_task_tick(curr
, cpu
);
5151 rq
->idle_at_tick
= idle_cpu(cpu
);
5152 trigger_load_balance(rq
, cpu
);
5156 notrace
unsigned long get_parent_ip(unsigned long addr
)
5158 if (in_lock_functions(addr
)) {
5159 addr
= CALLER_ADDR2
;
5160 if (in_lock_functions(addr
))
5161 addr
= CALLER_ADDR3
;
5166 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
5167 defined(CONFIG_PREEMPT_TRACER))
5169 void __kprobes
add_preempt_count(int val
)
5171 #ifdef CONFIG_DEBUG_PREEMPT
5175 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
5178 preempt_count() += val
;
5179 #ifdef CONFIG_DEBUG_PREEMPT
5181 * Spinlock count overflowing soon?
5183 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
5186 if (preempt_count() == val
)
5187 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5189 EXPORT_SYMBOL(add_preempt_count
);
5191 void __kprobes
sub_preempt_count(int val
)
5193 #ifdef CONFIG_DEBUG_PREEMPT
5197 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
5200 * Is the spinlock portion underflowing?
5202 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
5203 !(preempt_count() & PREEMPT_MASK
)))
5207 if (preempt_count() == val
)
5208 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
5209 preempt_count() -= val
;
5211 EXPORT_SYMBOL(sub_preempt_count
);
5216 * Print scheduling while atomic bug:
5218 static noinline
void __schedule_bug(struct task_struct
*prev
)
5220 struct pt_regs
*regs
= get_irq_regs();
5222 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
5223 prev
->comm
, prev
->pid
, preempt_count());
5225 debug_show_held_locks(prev
);
5227 if (irqs_disabled())
5228 print_irqtrace_events(prev
);
5237 * Various schedule()-time debugging checks and statistics:
5239 static inline void schedule_debug(struct task_struct
*prev
)
5242 * Test if we are atomic. Since do_exit() needs to call into
5243 * schedule() atomically, we ignore that path for now.
5244 * Otherwise, whine if we are scheduling when we should not be.
5246 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
5247 __schedule_bug(prev
);
5249 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
5251 schedstat_inc(this_rq(), sched_count
);
5252 #ifdef CONFIG_SCHEDSTATS
5253 if (unlikely(prev
->lock_depth
>= 0)) {
5254 schedstat_inc(this_rq(), bkl_count
);
5255 schedstat_inc(prev
, sched_info
.bkl_count
);
5260 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
5262 if (prev
->state
== TASK_RUNNING
) {
5263 u64 runtime
= prev
->se
.sum_exec_runtime
;
5265 runtime
-= prev
->se
.prev_sum_exec_runtime
;
5266 runtime
= min_t(u64
, runtime
, 2*sysctl_sched_migration_cost
);
5269 * In order to avoid avg_overlap growing stale when we are
5270 * indeed overlapping and hence not getting put to sleep, grow
5271 * the avg_overlap on preemption.
5273 * We use the average preemption runtime because that
5274 * correlates to the amount of cache footprint a task can
5277 update_avg(&prev
->se
.avg_overlap
, runtime
);
5279 prev
->sched_class
->put_prev_task(rq
, prev
);
5283 * Pick up the highest-prio task:
5285 static inline struct task_struct
*
5286 pick_next_task(struct rq
*rq
)
5288 const struct sched_class
*class;
5289 struct task_struct
*p
;
5292 * Optimization: we know that if all tasks are in
5293 * the fair class we can call that function directly:
5295 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
5296 p
= fair_sched_class
.pick_next_task(rq
);
5301 class = sched_class_highest
;
5303 p
= class->pick_next_task(rq
);
5307 * Will never be NULL as the idle class always
5308 * returns a non-NULL p:
5310 class = class->next
;
5315 * schedule() is the main scheduler function.
5317 asmlinkage
void __sched
schedule(void)
5319 struct task_struct
*prev
, *next
;
5320 unsigned long *switch_count
;
5326 cpu
= smp_processor_id();
5330 switch_count
= &prev
->nivcsw
;
5332 release_kernel_lock(prev
);
5333 need_resched_nonpreemptible
:
5335 schedule_debug(prev
);
5337 if (sched_feat(HRTICK
))
5340 spin_lock_irq(&rq
->lock
);
5341 update_rq_clock(rq
);
5342 clear_tsk_need_resched(prev
);
5344 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
5345 if (unlikely(signal_pending_state(prev
->state
, prev
)))
5346 prev
->state
= TASK_RUNNING
;
5348 deactivate_task(rq
, prev
, 1);
5349 switch_count
= &prev
->nvcsw
;
5353 if (prev
->sched_class
->pre_schedule
)
5354 prev
->sched_class
->pre_schedule(rq
, prev
);
5357 if (unlikely(!rq
->nr_running
))
5358 idle_balance(cpu
, rq
);
5360 put_prev_task(rq
, prev
);
5361 next
= pick_next_task(rq
);
5363 if (likely(prev
!= next
)) {
5364 sched_info_switch(prev
, next
);
5365 perf_counter_task_sched_out(prev
, next
, cpu
);
5371 context_switch(rq
, prev
, next
); /* unlocks the rq */
5373 * the context switch might have flipped the stack from under
5374 * us, hence refresh the local variables.
5376 cpu
= smp_processor_id();
5379 spin_unlock_irq(&rq
->lock
);
5381 if (unlikely(reacquire_kernel_lock(current
) < 0))
5382 goto need_resched_nonpreemptible
;
5384 preempt_enable_no_resched();
5388 EXPORT_SYMBOL(schedule
);
5392 * Look out! "owner" is an entirely speculative pointer
5393 * access and not reliable.
5395 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
5400 if (!sched_feat(OWNER_SPIN
))
5403 #ifdef CONFIG_DEBUG_PAGEALLOC
5405 * Need to access the cpu field knowing that
5406 * DEBUG_PAGEALLOC could have unmapped it if
5407 * the mutex owner just released it and exited.
5409 if (probe_kernel_address(&owner
->cpu
, cpu
))
5416 * Even if the access succeeded (likely case),
5417 * the cpu field may no longer be valid.
5419 if (cpu
>= nr_cpumask_bits
)
5423 * We need to validate that we can do a
5424 * get_cpu() and that we have the percpu area.
5426 if (!cpu_online(cpu
))
5433 * Owner changed, break to re-assess state.
5435 if (lock
->owner
!= owner
)
5439 * Is that owner really running on that cpu?
5441 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
5451 #ifdef CONFIG_PREEMPT
5453 * this is the entry point to schedule() from in-kernel preemption
5454 * off of preempt_enable. Kernel preemptions off return from interrupt
5455 * occur there and call schedule directly.
5457 asmlinkage
void __sched
preempt_schedule(void)
5459 struct thread_info
*ti
= current_thread_info();
5462 * If there is a non-zero preempt_count or interrupts are disabled,
5463 * we do not want to preempt the current task. Just return..
5465 if (likely(ti
->preempt_count
|| irqs_disabled()))
5469 add_preempt_count(PREEMPT_ACTIVE
);
5471 sub_preempt_count(PREEMPT_ACTIVE
);
5474 * Check again in case we missed a preemption opportunity
5475 * between schedule and now.
5478 } while (need_resched());
5480 EXPORT_SYMBOL(preempt_schedule
);
5483 * this is the entry point to schedule() from kernel preemption
5484 * off of irq context.
5485 * Note, that this is called and return with irqs disabled. This will
5486 * protect us against recursive calling from irq.
5488 asmlinkage
void __sched
preempt_schedule_irq(void)
5490 struct thread_info
*ti
= current_thread_info();
5492 /* Catch callers which need to be fixed */
5493 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
5496 add_preempt_count(PREEMPT_ACTIVE
);
5499 local_irq_disable();
5500 sub_preempt_count(PREEMPT_ACTIVE
);
5503 * Check again in case we missed a preemption opportunity
5504 * between schedule and now.
5507 } while (need_resched());
5510 #endif /* CONFIG_PREEMPT */
5512 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
5515 return try_to_wake_up(curr
->private, mode
, sync
);
5517 EXPORT_SYMBOL(default_wake_function
);
5520 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5521 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5522 * number) then we wake all the non-exclusive tasks and one exclusive task.
5524 * There are circumstances in which we can try to wake a task which has already
5525 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5526 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5528 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
5529 int nr_exclusive
, int sync
, void *key
)
5531 wait_queue_t
*curr
, *next
;
5533 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
5534 unsigned flags
= curr
->flags
;
5536 if (curr
->func(curr
, mode
, sync
, key
) &&
5537 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
5543 * __wake_up - wake up threads blocked on a waitqueue.
5545 * @mode: which threads
5546 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5547 * @key: is directly passed to the wakeup function
5549 * It may be assumed that this function implies a write memory barrier before
5550 * changing the task state if and only if any tasks are woken up.
5552 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
5553 int nr_exclusive
, void *key
)
5555 unsigned long flags
;
5557 spin_lock_irqsave(&q
->lock
, flags
);
5558 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
5559 spin_unlock_irqrestore(&q
->lock
, flags
);
5561 EXPORT_SYMBOL(__wake_up
);
5564 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5566 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
5568 __wake_up_common(q
, mode
, 1, 0, NULL
);
5571 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
5573 __wake_up_common(q
, mode
, 1, 0, key
);
5577 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5579 * @mode: which threads
5580 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5581 * @key: opaque value to be passed to wakeup targets
5583 * The sync wakeup differs that the waker knows that it will schedule
5584 * away soon, so while the target thread will be woken up, it will not
5585 * be migrated to another CPU - ie. the two threads are 'synchronized'
5586 * with each other. This can prevent needless bouncing between CPUs.
5588 * On UP it can prevent extra preemption.
5590 * It may be assumed that this function implies a write memory barrier before
5591 * changing the task state if and only if any tasks are woken up.
5593 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
5594 int nr_exclusive
, void *key
)
5596 unsigned long flags
;
5602 if (unlikely(!nr_exclusive
))
5605 spin_lock_irqsave(&q
->lock
, flags
);
5606 __wake_up_common(q
, mode
, nr_exclusive
, sync
, key
);
5607 spin_unlock_irqrestore(&q
->lock
, flags
);
5609 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
5612 * __wake_up_sync - see __wake_up_sync_key()
5614 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
5616 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
5618 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
5621 * complete: - signals a single thread waiting on this completion
5622 * @x: holds the state of this particular completion
5624 * This will wake up a single thread waiting on this completion. Threads will be
5625 * awakened in the same order in which they were queued.
5627 * See also complete_all(), wait_for_completion() and related routines.
5629 * It may be assumed that this function implies a write memory barrier before
5630 * changing the task state if and only if any tasks are woken up.
5632 void complete(struct completion
*x
)
5634 unsigned long flags
;
5636 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5638 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
5639 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5641 EXPORT_SYMBOL(complete
);
5644 * complete_all: - signals all threads waiting on this completion
5645 * @x: holds the state of this particular completion
5647 * This will wake up all threads waiting on this particular completion event.
5649 * It may be assumed that this function implies a write memory barrier before
5650 * changing the task state if and only if any tasks are woken up.
5652 void complete_all(struct completion
*x
)
5654 unsigned long flags
;
5656 spin_lock_irqsave(&x
->wait
.lock
, flags
);
5657 x
->done
+= UINT_MAX
/2;
5658 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
5659 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
5661 EXPORT_SYMBOL(complete_all
);
5663 static inline long __sched
5664 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
5667 DECLARE_WAITQUEUE(wait
, current
);
5669 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
5670 __add_wait_queue_tail(&x
->wait
, &wait
);
5672 if (signal_pending_state(state
, current
)) {
5673 timeout
= -ERESTARTSYS
;
5676 __set_current_state(state
);
5677 spin_unlock_irq(&x
->wait
.lock
);
5678 timeout
= schedule_timeout(timeout
);
5679 spin_lock_irq(&x
->wait
.lock
);
5680 } while (!x
->done
&& timeout
);
5681 __remove_wait_queue(&x
->wait
, &wait
);
5686 return timeout
?: 1;
5690 wait_for_common(struct completion
*x
, long timeout
, int state
)
5694 spin_lock_irq(&x
->wait
.lock
);
5695 timeout
= do_wait_for_common(x
, timeout
, state
);
5696 spin_unlock_irq(&x
->wait
.lock
);
5701 * wait_for_completion: - waits for completion of a task
5702 * @x: holds the state of this particular completion
5704 * This waits to be signaled for completion of a specific task. It is NOT
5705 * interruptible and there is no timeout.
5707 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5708 * and interrupt capability. Also see complete().
5710 void __sched
wait_for_completion(struct completion
*x
)
5712 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
5714 EXPORT_SYMBOL(wait_for_completion
);
5717 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5718 * @x: holds the state of this particular completion
5719 * @timeout: timeout value in jiffies
5721 * This waits for either a completion of a specific task to be signaled or for a
5722 * specified timeout to expire. The timeout is in jiffies. It is not
5725 unsigned long __sched
5726 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
5728 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
5730 EXPORT_SYMBOL(wait_for_completion_timeout
);
5733 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5734 * @x: holds the state of this particular completion
5736 * This waits for completion of a specific task to be signaled. It is
5739 int __sched
wait_for_completion_interruptible(struct completion
*x
)
5741 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
5742 if (t
== -ERESTARTSYS
)
5746 EXPORT_SYMBOL(wait_for_completion_interruptible
);
5749 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5750 * @x: holds the state of this particular completion
5751 * @timeout: timeout value in jiffies
5753 * This waits for either a completion of a specific task to be signaled or for a
5754 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5756 unsigned long __sched
5757 wait_for_completion_interruptible_timeout(struct completion
*x
,
5758 unsigned long timeout
)
5760 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
5762 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
5765 * wait_for_completion_killable: - waits for completion of a task (killable)
5766 * @x: holds the state of this particular completion
5768 * This waits to be signaled for completion of a specific task. It can be
5769 * interrupted by a kill signal.
5771 int __sched
wait_for_completion_killable(struct completion
*x
)
5773 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
5774 if (t
== -ERESTARTSYS
)
5778 EXPORT_SYMBOL(wait_for_completion_killable
);
5781 * try_wait_for_completion - try to decrement a completion without blocking
5782 * @x: completion structure
5784 * Returns: 0 if a decrement cannot be done without blocking
5785 * 1 if a decrement succeeded.
5787 * If a completion is being used as a counting completion,
5788 * attempt to decrement the counter without blocking. This
5789 * enables us to avoid waiting if the resource the completion
5790 * is protecting is not available.
5792 bool try_wait_for_completion(struct completion
*x
)
5796 spin_lock_irq(&x
->wait
.lock
);
5801 spin_unlock_irq(&x
->wait
.lock
);
5804 EXPORT_SYMBOL(try_wait_for_completion
);
5807 * completion_done - Test to see if a completion has any waiters
5808 * @x: completion structure
5810 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5811 * 1 if there are no waiters.
5814 bool completion_done(struct completion
*x
)
5818 spin_lock_irq(&x
->wait
.lock
);
5821 spin_unlock_irq(&x
->wait
.lock
);
5824 EXPORT_SYMBOL(completion_done
);
5827 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5829 unsigned long flags
;
5832 init_waitqueue_entry(&wait
, current
);
5834 __set_current_state(state
);
5836 spin_lock_irqsave(&q
->lock
, flags
);
5837 __add_wait_queue(q
, &wait
);
5838 spin_unlock(&q
->lock
);
5839 timeout
= schedule_timeout(timeout
);
5840 spin_lock_irq(&q
->lock
);
5841 __remove_wait_queue(q
, &wait
);
5842 spin_unlock_irqrestore(&q
->lock
, flags
);
5847 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
5849 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5851 EXPORT_SYMBOL(interruptible_sleep_on
);
5854 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5856 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
5858 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
5860 void __sched
sleep_on(wait_queue_head_t
*q
)
5862 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5864 EXPORT_SYMBOL(sleep_on
);
5866 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5868 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5870 EXPORT_SYMBOL(sleep_on_timeout
);
5872 #ifdef CONFIG_RT_MUTEXES
5875 * rt_mutex_setprio - set the current priority of a task
5877 * @prio: prio value (kernel-internal form)
5879 * This function changes the 'effective' priority of a task. It does
5880 * not touch ->normal_prio like __setscheduler().
5882 * Used by the rt_mutex code to implement priority inheritance logic.
5884 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
5886 unsigned long flags
;
5887 int oldprio
, on_rq
, running
;
5889 const struct sched_class
*prev_class
= p
->sched_class
;
5891 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
5893 rq
= task_rq_lock(p
, &flags
);
5894 update_rq_clock(rq
);
5897 on_rq
= p
->se
.on_rq
;
5898 running
= task_current(rq
, p
);
5900 dequeue_task(rq
, p
, 0);
5902 p
->sched_class
->put_prev_task(rq
, p
);
5905 p
->sched_class
= &rt_sched_class
;
5907 p
->sched_class
= &fair_sched_class
;
5912 p
->sched_class
->set_curr_task(rq
);
5914 enqueue_task(rq
, p
, 0);
5916 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5918 task_rq_unlock(rq
, &flags
);
5923 void set_user_nice(struct task_struct
*p
, long nice
)
5925 int old_prio
, delta
, on_rq
;
5926 unsigned long flags
;
5929 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
5932 * We have to be careful, if called from sys_setpriority(),
5933 * the task might be in the middle of scheduling on another CPU.
5935 rq
= task_rq_lock(p
, &flags
);
5936 update_rq_clock(rq
);
5938 * The RT priorities are set via sched_setscheduler(), but we still
5939 * allow the 'normal' nice value to be set - but as expected
5940 * it wont have any effect on scheduling until the task is
5941 * SCHED_FIFO/SCHED_RR:
5943 if (task_has_rt_policy(p
)) {
5944 p
->static_prio
= NICE_TO_PRIO(nice
);
5947 on_rq
= p
->se
.on_rq
;
5949 dequeue_task(rq
, p
, 0);
5951 p
->static_prio
= NICE_TO_PRIO(nice
);
5954 p
->prio
= effective_prio(p
);
5955 delta
= p
->prio
- old_prio
;
5958 enqueue_task(rq
, p
, 0);
5960 * If the task increased its priority or is running and
5961 * lowered its priority, then reschedule its CPU:
5963 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
5964 resched_task(rq
->curr
);
5967 task_rq_unlock(rq
, &flags
);
5969 EXPORT_SYMBOL(set_user_nice
);
5972 * can_nice - check if a task can reduce its nice value
5976 int can_nice(const struct task_struct
*p
, const int nice
)
5978 /* convert nice value [19,-20] to rlimit style value [1,40] */
5979 int nice_rlim
= 20 - nice
;
5981 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
5982 capable(CAP_SYS_NICE
));
5985 #ifdef __ARCH_WANT_SYS_NICE
5988 * sys_nice - change the priority of the current process.
5989 * @increment: priority increment
5991 * sys_setpriority is a more generic, but much slower function that
5992 * does similar things.
5994 SYSCALL_DEFINE1(nice
, int, increment
)
5999 * Setpriority might change our priority at the same moment.
6000 * We don't have to worry. Conceptually one call occurs first
6001 * and we have a single winner.
6003 if (increment
< -40)
6008 nice
= TASK_NICE(current
) + increment
;
6014 if (increment
< 0 && !can_nice(current
, nice
))
6017 retval
= security_task_setnice(current
, nice
);
6021 set_user_nice(current
, nice
);
6028 * task_prio - return the priority value of a given task.
6029 * @p: the task in question.
6031 * This is the priority value as seen by users in /proc.
6032 * RT tasks are offset by -200. Normal tasks are centered
6033 * around 0, value goes from -16 to +15.
6035 int task_prio(const struct task_struct
*p
)
6037 return p
->prio
- MAX_RT_PRIO
;
6041 * task_nice - return the nice value of a given task.
6042 * @p: the task in question.
6044 int task_nice(const struct task_struct
*p
)
6046 return TASK_NICE(p
);
6048 EXPORT_SYMBOL(task_nice
);
6051 * idle_cpu - is a given cpu idle currently?
6052 * @cpu: the processor in question.
6054 int idle_cpu(int cpu
)
6056 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
6060 * idle_task - return the idle task for a given cpu.
6061 * @cpu: the processor in question.
6063 struct task_struct
*idle_task(int cpu
)
6065 return cpu_rq(cpu
)->idle
;
6069 * find_process_by_pid - find a process with a matching PID value.
6070 * @pid: the pid in question.
6072 static struct task_struct
*find_process_by_pid(pid_t pid
)
6074 return pid
? find_task_by_vpid(pid
) : current
;
6077 /* Actually do priority change: must hold rq lock. */
6079 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
6081 BUG_ON(p
->se
.on_rq
);
6084 switch (p
->policy
) {
6088 p
->sched_class
= &fair_sched_class
;
6092 p
->sched_class
= &rt_sched_class
;
6096 p
->rt_priority
= prio
;
6097 p
->normal_prio
= normal_prio(p
);
6098 /* we are holding p->pi_lock already */
6099 p
->prio
= rt_mutex_getprio(p
);
6104 * check the target process has a UID that matches the current process's
6106 static bool check_same_owner(struct task_struct
*p
)
6108 const struct cred
*cred
= current_cred(), *pcred
;
6112 pcred
= __task_cred(p
);
6113 match
= (cred
->euid
== pcred
->euid
||
6114 cred
->euid
== pcred
->uid
);
6119 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
6120 struct sched_param
*param
, bool user
)
6122 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
6123 unsigned long flags
;
6124 const struct sched_class
*prev_class
= p
->sched_class
;
6128 /* may grab non-irq protected spin_locks */
6129 BUG_ON(in_interrupt());
6131 /* double check policy once rq lock held */
6133 reset_on_fork
= p
->sched_reset_on_fork
;
6134 policy
= oldpolicy
= p
->policy
;
6136 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
6137 policy
&= ~SCHED_RESET_ON_FORK
;
6139 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
6140 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
6141 policy
!= SCHED_IDLE
)
6146 * Valid priorities for SCHED_FIFO and SCHED_RR are
6147 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
6148 * SCHED_BATCH and SCHED_IDLE is 0.
6150 if (param
->sched_priority
< 0 ||
6151 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
6152 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
6154 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
6158 * Allow unprivileged RT tasks to decrease priority:
6160 if (user
&& !capable(CAP_SYS_NICE
)) {
6161 if (rt_policy(policy
)) {
6162 unsigned long rlim_rtprio
;
6164 if (!lock_task_sighand(p
, &flags
))
6166 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
6167 unlock_task_sighand(p
, &flags
);
6169 /* can't set/change the rt policy */
6170 if (policy
!= p
->policy
&& !rlim_rtprio
)
6173 /* can't increase priority */
6174 if (param
->sched_priority
> p
->rt_priority
&&
6175 param
->sched_priority
> rlim_rtprio
)
6179 * Like positive nice levels, dont allow tasks to
6180 * move out of SCHED_IDLE either:
6182 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
6185 /* can't change other user's priorities */
6186 if (!check_same_owner(p
))
6189 /* Normal users shall not reset the sched_reset_on_fork flag */
6190 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
6195 #ifdef CONFIG_RT_GROUP_SCHED
6197 * Do not allow realtime tasks into groups that have no runtime
6200 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
6201 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
6205 retval
= security_task_setscheduler(p
, policy
, param
);
6211 * make sure no PI-waiters arrive (or leave) while we are
6212 * changing the priority of the task:
6214 spin_lock_irqsave(&p
->pi_lock
, flags
);
6216 * To be able to change p->policy safely, the apropriate
6217 * runqueue lock must be held.
6219 rq
= __task_rq_lock(p
);
6220 /* recheck policy now with rq lock held */
6221 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
6222 policy
= oldpolicy
= -1;
6223 __task_rq_unlock(rq
);
6224 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6227 update_rq_clock(rq
);
6228 on_rq
= p
->se
.on_rq
;
6229 running
= task_current(rq
, p
);
6231 deactivate_task(rq
, p
, 0);
6233 p
->sched_class
->put_prev_task(rq
, p
);
6235 p
->sched_reset_on_fork
= reset_on_fork
;
6238 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
6241 p
->sched_class
->set_curr_task(rq
);
6243 activate_task(rq
, p
, 0);
6245 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
6247 __task_rq_unlock(rq
);
6248 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
6250 rt_mutex_adjust_pi(p
);
6256 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
6257 * @p: the task in question.
6258 * @policy: new policy.
6259 * @param: structure containing the new RT priority.
6261 * NOTE that the task may be already dead.
6263 int sched_setscheduler(struct task_struct
*p
, int policy
,
6264 struct sched_param
*param
)
6266 return __sched_setscheduler(p
, policy
, param
, true);
6268 EXPORT_SYMBOL_GPL(sched_setscheduler
);
6271 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
6272 * @p: the task in question.
6273 * @policy: new policy.
6274 * @param: structure containing the new RT priority.
6276 * Just like sched_setscheduler, only don't bother checking if the
6277 * current context has permission. For example, this is needed in
6278 * stop_machine(): we create temporary high priority worker threads,
6279 * but our caller might not have that capability.
6281 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
6282 struct sched_param
*param
)
6284 return __sched_setscheduler(p
, policy
, param
, false);
6288 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
6290 struct sched_param lparam
;
6291 struct task_struct
*p
;
6294 if (!param
|| pid
< 0)
6296 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
6301 p
= find_process_by_pid(pid
);
6303 retval
= sched_setscheduler(p
, policy
, &lparam
);
6310 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
6311 * @pid: the pid in question.
6312 * @policy: new policy.
6313 * @param: structure containing the new RT priority.
6315 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
6316 struct sched_param __user
*, param
)
6318 /* negative values for policy are not valid */
6322 return do_sched_setscheduler(pid
, policy
, param
);
6326 * sys_sched_setparam - set/change the RT priority of a thread
6327 * @pid: the pid in question.
6328 * @param: structure containing the new RT priority.
6330 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6332 return do_sched_setscheduler(pid
, -1, param
);
6336 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6337 * @pid: the pid in question.
6339 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
6341 struct task_struct
*p
;
6348 read_lock(&tasklist_lock
);
6349 p
= find_process_by_pid(pid
);
6351 retval
= security_task_getscheduler(p
);
6354 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
6356 read_unlock(&tasklist_lock
);
6361 * sys_sched_getparam - get the RT priority of a thread
6362 * @pid: the pid in question.
6363 * @param: structure containing the RT priority.
6365 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
6367 struct sched_param lp
;
6368 struct task_struct
*p
;
6371 if (!param
|| pid
< 0)
6374 read_lock(&tasklist_lock
);
6375 p
= find_process_by_pid(pid
);
6380 retval
= security_task_getscheduler(p
);
6384 lp
.sched_priority
= p
->rt_priority
;
6385 read_unlock(&tasklist_lock
);
6388 * This one might sleep, we cannot do it with a spinlock held ...
6390 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
6395 read_unlock(&tasklist_lock
);
6399 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
6401 cpumask_var_t cpus_allowed
, new_mask
;
6402 struct task_struct
*p
;
6406 read_lock(&tasklist_lock
);
6408 p
= find_process_by_pid(pid
);
6410 read_unlock(&tasklist_lock
);
6416 * It is not safe to call set_cpus_allowed with the
6417 * tasklist_lock held. We will bump the task_struct's
6418 * usage count and then drop tasklist_lock.
6421 read_unlock(&tasklist_lock
);
6423 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
6427 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
6429 goto out_free_cpus_allowed
;
6432 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
6435 retval
= security_task_setscheduler(p
, 0, NULL
);
6439 cpuset_cpus_allowed(p
, cpus_allowed
);
6440 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
6442 retval
= set_cpus_allowed_ptr(p
, new_mask
);
6445 cpuset_cpus_allowed(p
, cpus_allowed
);
6446 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
6448 * We must have raced with a concurrent cpuset
6449 * update. Just reset the cpus_allowed to the
6450 * cpuset's cpus_allowed
6452 cpumask_copy(new_mask
, cpus_allowed
);
6457 free_cpumask_var(new_mask
);
6458 out_free_cpus_allowed
:
6459 free_cpumask_var(cpus_allowed
);
6466 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
6467 struct cpumask
*new_mask
)
6469 if (len
< cpumask_size())
6470 cpumask_clear(new_mask
);
6471 else if (len
> cpumask_size())
6472 len
= cpumask_size();
6474 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
6478 * sys_sched_setaffinity - set the cpu affinity of a process
6479 * @pid: pid of the process
6480 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6481 * @user_mask_ptr: user-space pointer to the new cpu mask
6483 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
6484 unsigned long __user
*, user_mask_ptr
)
6486 cpumask_var_t new_mask
;
6489 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
6492 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
6494 retval
= sched_setaffinity(pid
, new_mask
);
6495 free_cpumask_var(new_mask
);
6499 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
6501 struct task_struct
*p
;
6505 read_lock(&tasklist_lock
);
6508 p
= find_process_by_pid(pid
);
6512 retval
= security_task_getscheduler(p
);
6516 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
6519 read_unlock(&tasklist_lock
);
6526 * sys_sched_getaffinity - get the cpu affinity of a process
6527 * @pid: pid of the process
6528 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6529 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6531 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
6532 unsigned long __user
*, user_mask_ptr
)
6537 if (len
< cpumask_size())
6540 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
6543 ret
= sched_getaffinity(pid
, mask
);
6545 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
6548 ret
= cpumask_size();
6550 free_cpumask_var(mask
);
6556 * sys_sched_yield - yield the current processor to other threads.
6558 * This function yields the current CPU to other tasks. If there are no
6559 * other threads running on this CPU then this function will return.
6561 SYSCALL_DEFINE0(sched_yield
)
6563 struct rq
*rq
= this_rq_lock();
6565 schedstat_inc(rq
, yld_count
);
6566 current
->sched_class
->yield_task(rq
);
6569 * Since we are going to call schedule() anyway, there's
6570 * no need to preempt or enable interrupts:
6572 __release(rq
->lock
);
6573 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
6574 _raw_spin_unlock(&rq
->lock
);
6575 preempt_enable_no_resched();
6582 static void __cond_resched(void)
6584 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
6585 __might_sleep(__FILE__
, __LINE__
);
6588 * The BKS might be reacquired before we have dropped
6589 * PREEMPT_ACTIVE, which could trigger a second
6590 * cond_resched() call.
6593 add_preempt_count(PREEMPT_ACTIVE
);
6595 sub_preempt_count(PREEMPT_ACTIVE
);
6596 } while (need_resched());
6599 int __sched
_cond_resched(void)
6601 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
6602 system_state
== SYSTEM_RUNNING
) {
6608 EXPORT_SYMBOL(_cond_resched
);
6611 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
6612 * call schedule, and on return reacquire the lock.
6614 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6615 * operations here to prevent schedule() from being called twice (once via
6616 * spin_unlock(), once by hand).
6618 int cond_resched_lock(spinlock_t
*lock
)
6620 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
6623 if (spin_needbreak(lock
) || resched
) {
6625 if (resched
&& need_resched())
6634 EXPORT_SYMBOL(cond_resched_lock
);
6636 int __sched
cond_resched_softirq(void)
6638 BUG_ON(!in_softirq());
6640 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
6648 EXPORT_SYMBOL(cond_resched_softirq
);
6651 * yield - yield the current processor to other threads.
6653 * This is a shortcut for kernel-space yielding - it marks the
6654 * thread runnable and calls sys_sched_yield().
6656 void __sched
yield(void)
6658 set_current_state(TASK_RUNNING
);
6661 EXPORT_SYMBOL(yield
);
6664 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6665 * that process accounting knows that this is a task in IO wait state.
6667 * But don't do that if it is a deliberate, throttling IO wait (this task
6668 * has set its backing_dev_info: the queue against which it should throttle)
6670 void __sched
io_schedule(void)
6672 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
6674 delayacct_blkio_start();
6675 atomic_inc(&rq
->nr_iowait
);
6677 atomic_dec(&rq
->nr_iowait
);
6678 delayacct_blkio_end();
6680 EXPORT_SYMBOL(io_schedule
);
6682 long __sched
io_schedule_timeout(long timeout
)
6684 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
6687 delayacct_blkio_start();
6688 atomic_inc(&rq
->nr_iowait
);
6689 ret
= schedule_timeout(timeout
);
6690 atomic_dec(&rq
->nr_iowait
);
6691 delayacct_blkio_end();
6696 * sys_sched_get_priority_max - return maximum RT priority.
6697 * @policy: scheduling class.
6699 * this syscall returns the maximum rt_priority that can be used
6700 * by a given scheduling class.
6702 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
6709 ret
= MAX_USER_RT_PRIO
-1;
6721 * sys_sched_get_priority_min - return minimum RT priority.
6722 * @policy: scheduling class.
6724 * this syscall returns the minimum rt_priority that can be used
6725 * by a given scheduling class.
6727 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
6745 * sys_sched_rr_get_interval - return the default timeslice of a process.
6746 * @pid: pid of the process.
6747 * @interval: userspace pointer to the timeslice value.
6749 * this syscall writes the default timeslice value of a given process
6750 * into the user-space timespec buffer. A value of '0' means infinity.
6752 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
6753 struct timespec __user
*, interval
)
6755 struct task_struct
*p
;
6756 unsigned int time_slice
;
6764 read_lock(&tasklist_lock
);
6765 p
= find_process_by_pid(pid
);
6769 retval
= security_task_getscheduler(p
);
6774 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6775 * tasks that are on an otherwise idle runqueue:
6778 if (p
->policy
== SCHED_RR
) {
6779 time_slice
= DEF_TIMESLICE
;
6780 } else if (p
->policy
!= SCHED_FIFO
) {
6781 struct sched_entity
*se
= &p
->se
;
6782 unsigned long flags
;
6785 rq
= task_rq_lock(p
, &flags
);
6786 if (rq
->cfs
.load
.weight
)
6787 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
6788 task_rq_unlock(rq
, &flags
);
6790 read_unlock(&tasklist_lock
);
6791 jiffies_to_timespec(time_slice
, &t
);
6792 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
6796 read_unlock(&tasklist_lock
);
6800 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
6802 void sched_show_task(struct task_struct
*p
)
6804 unsigned long free
= 0;
6807 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
6808 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
6809 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
6810 #if BITS_PER_LONG == 32
6811 if (state
== TASK_RUNNING
)
6812 printk(KERN_CONT
" running ");
6814 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
6816 if (state
== TASK_RUNNING
)
6817 printk(KERN_CONT
" running task ");
6819 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
6821 #ifdef CONFIG_DEBUG_STACK_USAGE
6822 free
= stack_not_used(p
);
6824 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
6825 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
6826 (unsigned long)task_thread_info(p
)->flags
);
6828 show_stack(p
, NULL
);
6831 void show_state_filter(unsigned long state_filter
)
6833 struct task_struct
*g
, *p
;
6835 #if BITS_PER_LONG == 32
6837 " task PC stack pid father\n");
6840 " task PC stack pid father\n");
6842 read_lock(&tasklist_lock
);
6843 do_each_thread(g
, p
) {
6845 * reset the NMI-timeout, listing all files on a slow
6846 * console might take alot of time:
6848 touch_nmi_watchdog();
6849 if (!state_filter
|| (p
->state
& state_filter
))
6851 } while_each_thread(g
, p
);
6853 touch_all_softlockup_watchdogs();
6855 #ifdef CONFIG_SCHED_DEBUG
6856 sysrq_sched_debug_show();
6858 read_unlock(&tasklist_lock
);
6860 * Only show locks if all tasks are dumped:
6862 if (state_filter
== -1)
6863 debug_show_all_locks();
6866 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6868 idle
->sched_class
= &idle_sched_class
;
6872 * init_idle - set up an idle thread for a given CPU
6873 * @idle: task in question
6874 * @cpu: cpu the idle task belongs to
6876 * NOTE: this function does not set the idle thread's NEED_RESCHED
6877 * flag, to make booting more robust.
6879 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6881 struct rq
*rq
= cpu_rq(cpu
);
6882 unsigned long flags
;
6884 spin_lock_irqsave(&rq
->lock
, flags
);
6887 idle
->se
.exec_start
= sched_clock();
6889 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
6890 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
6891 __set_task_cpu(idle
, cpu
);
6893 rq
->curr
= rq
->idle
= idle
;
6894 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6897 spin_unlock_irqrestore(&rq
->lock
, flags
);
6899 /* Set the preempt count _outside_ the spinlocks! */
6900 #if defined(CONFIG_PREEMPT)
6901 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
6903 task_thread_info(idle
)->preempt_count
= 0;
6906 * The idle tasks have their own, simple scheduling class:
6908 idle
->sched_class
= &idle_sched_class
;
6909 ftrace_graph_init_task(idle
);
6913 * In a system that switches off the HZ timer nohz_cpu_mask
6914 * indicates which cpus entered this state. This is used
6915 * in the rcu update to wait only for active cpus. For system
6916 * which do not switch off the HZ timer nohz_cpu_mask should
6917 * always be CPU_BITS_NONE.
6919 cpumask_var_t nohz_cpu_mask
;
6922 * Increase the granularity value when there are more CPUs,
6923 * because with more CPUs the 'effective latency' as visible
6924 * to users decreases. But the relationship is not linear,
6925 * so pick a second-best guess by going with the log2 of the
6928 * This idea comes from the SD scheduler of Con Kolivas:
6930 static inline void sched_init_granularity(void)
6932 unsigned int factor
= 1 + ilog2(num_online_cpus());
6933 const unsigned long limit
= 200000000;
6935 sysctl_sched_min_granularity
*= factor
;
6936 if (sysctl_sched_min_granularity
> limit
)
6937 sysctl_sched_min_granularity
= limit
;
6939 sysctl_sched_latency
*= factor
;
6940 if (sysctl_sched_latency
> limit
)
6941 sysctl_sched_latency
= limit
;
6943 sysctl_sched_wakeup_granularity
*= factor
;
6945 sysctl_sched_shares_ratelimit
*= factor
;
6950 * This is how migration works:
6952 * 1) we queue a struct migration_req structure in the source CPU's
6953 * runqueue and wake up that CPU's migration thread.
6954 * 2) we down() the locked semaphore => thread blocks.
6955 * 3) migration thread wakes up (implicitly it forces the migrated
6956 * thread off the CPU)
6957 * 4) it gets the migration request and checks whether the migrated
6958 * task is still in the wrong runqueue.
6959 * 5) if it's in the wrong runqueue then the migration thread removes
6960 * it and puts it into the right queue.
6961 * 6) migration thread up()s the semaphore.
6962 * 7) we wake up and the migration is done.
6966 * Change a given task's CPU affinity. Migrate the thread to a
6967 * proper CPU and schedule it away if the CPU it's executing on
6968 * is removed from the allowed bitmask.
6970 * NOTE: the caller must have a valid reference to the task, the
6971 * task must not exit() & deallocate itself prematurely. The
6972 * call is not atomic; no spinlocks may be held.
6974 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
6976 struct migration_req req
;
6977 unsigned long flags
;
6981 rq
= task_rq_lock(p
, &flags
);
6982 if (!cpumask_intersects(new_mask
, cpu_online_mask
)) {
6987 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
6988 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
6993 if (p
->sched_class
->set_cpus_allowed
)
6994 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
6996 cpumask_copy(&p
->cpus_allowed
, new_mask
);
6997 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
7000 /* Can the task run on the task's current CPU? If so, we're done */
7001 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
7004 if (migrate_task(p
, cpumask_any_and(cpu_online_mask
, new_mask
), &req
)) {
7005 /* Need help from migration thread: drop lock and wait. */
7006 task_rq_unlock(rq
, &flags
);
7007 wake_up_process(rq
->migration_thread
);
7008 wait_for_completion(&req
.done
);
7009 tlb_migrate_finish(p
->mm
);
7013 task_rq_unlock(rq
, &flags
);
7017 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
7020 * Move (not current) task off this cpu, onto dest cpu. We're doing
7021 * this because either it can't run here any more (set_cpus_allowed()
7022 * away from this CPU, or CPU going down), or because we're
7023 * attempting to rebalance this task on exec (sched_exec).
7025 * So we race with normal scheduler movements, but that's OK, as long
7026 * as the task is no longer on this CPU.
7028 * Returns non-zero if task was successfully migrated.
7030 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7032 struct rq
*rq_dest
, *rq_src
;
7035 if (unlikely(!cpu_active(dest_cpu
)))
7038 rq_src
= cpu_rq(src_cpu
);
7039 rq_dest
= cpu_rq(dest_cpu
);
7041 double_rq_lock(rq_src
, rq_dest
);
7042 /* Already moved. */
7043 if (task_cpu(p
) != src_cpu
)
7045 /* Affinity changed (again). */
7046 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7049 on_rq
= p
->se
.on_rq
;
7051 deactivate_task(rq_src
, p
, 0);
7053 set_task_cpu(p
, dest_cpu
);
7055 activate_task(rq_dest
, p
, 0);
7056 check_preempt_curr(rq_dest
, p
, 0);
7061 double_rq_unlock(rq_src
, rq_dest
);
7066 * migration_thread - this is a highprio system thread that performs
7067 * thread migration by bumping thread off CPU then 'pushing' onto
7070 static int migration_thread(void *data
)
7072 int cpu
= (long)data
;
7076 BUG_ON(rq
->migration_thread
!= current
);
7078 set_current_state(TASK_INTERRUPTIBLE
);
7079 while (!kthread_should_stop()) {
7080 struct migration_req
*req
;
7081 struct list_head
*head
;
7083 spin_lock_irq(&rq
->lock
);
7085 if (cpu_is_offline(cpu
)) {
7086 spin_unlock_irq(&rq
->lock
);
7090 if (rq
->active_balance
) {
7091 active_load_balance(rq
, cpu
);
7092 rq
->active_balance
= 0;
7095 head
= &rq
->migration_queue
;
7097 if (list_empty(head
)) {
7098 spin_unlock_irq(&rq
->lock
);
7100 set_current_state(TASK_INTERRUPTIBLE
);
7103 req
= list_entry(head
->next
, struct migration_req
, list
);
7104 list_del_init(head
->next
);
7106 spin_unlock(&rq
->lock
);
7107 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
7110 complete(&req
->done
);
7112 __set_current_state(TASK_RUNNING
);
7117 #ifdef CONFIG_HOTPLUG_CPU
7119 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
7123 local_irq_disable();
7124 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
7130 * Figure out where task on dead CPU should go, use force if necessary.
7132 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
7135 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(dead_cpu
));
7138 /* Look for allowed, online CPU in same node. */
7139 for_each_cpu_and(dest_cpu
, nodemask
, cpu_online_mask
)
7140 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
7143 /* Any allowed, online CPU? */
7144 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_online_mask
);
7145 if (dest_cpu
< nr_cpu_ids
)
7148 /* No more Mr. Nice Guy. */
7149 if (dest_cpu
>= nr_cpu_ids
) {
7150 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
7151 dest_cpu
= cpumask_any_and(cpu_online_mask
, &p
->cpus_allowed
);
7154 * Don't tell them about moving exiting tasks or
7155 * kernel threads (both mm NULL), since they never
7158 if (p
->mm
&& printk_ratelimit()) {
7159 printk(KERN_INFO
"process %d (%s) no "
7160 "longer affine to cpu%d\n",
7161 task_pid_nr(p
), p
->comm
, dead_cpu
);
7166 /* It can have affinity changed while we were choosing. */
7167 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
7172 * While a dead CPU has no uninterruptible tasks queued at this point,
7173 * it might still have a nonzero ->nr_uninterruptible counter, because
7174 * for performance reasons the counter is not stricly tracking tasks to
7175 * their home CPUs. So we just add the counter to another CPU's counter,
7176 * to keep the global sum constant after CPU-down:
7178 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
7180 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_online_mask
));
7181 unsigned long flags
;
7183 local_irq_save(flags
);
7184 double_rq_lock(rq_src
, rq_dest
);
7185 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
7186 rq_src
->nr_uninterruptible
= 0;
7187 double_rq_unlock(rq_src
, rq_dest
);
7188 local_irq_restore(flags
);
7191 /* Run through task list and migrate tasks from the dead cpu. */
7192 static void migrate_live_tasks(int src_cpu
)
7194 struct task_struct
*p
, *t
;
7196 read_lock(&tasklist_lock
);
7198 do_each_thread(t
, p
) {
7202 if (task_cpu(p
) == src_cpu
)
7203 move_task_off_dead_cpu(src_cpu
, p
);
7204 } while_each_thread(t
, p
);
7206 read_unlock(&tasklist_lock
);
7210 * Schedules idle task to be the next runnable task on current CPU.
7211 * It does so by boosting its priority to highest possible.
7212 * Used by CPU offline code.
7214 void sched_idle_next(void)
7216 int this_cpu
= smp_processor_id();
7217 struct rq
*rq
= cpu_rq(this_cpu
);
7218 struct task_struct
*p
= rq
->idle
;
7219 unsigned long flags
;
7221 /* cpu has to be offline */
7222 BUG_ON(cpu_online(this_cpu
));
7225 * Strictly not necessary since rest of the CPUs are stopped by now
7226 * and interrupts disabled on the current cpu.
7228 spin_lock_irqsave(&rq
->lock
, flags
);
7230 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7232 update_rq_clock(rq
);
7233 activate_task(rq
, p
, 0);
7235 spin_unlock_irqrestore(&rq
->lock
, flags
);
7239 * Ensures that the idle task is using init_mm right before its cpu goes
7242 void idle_task_exit(void)
7244 struct mm_struct
*mm
= current
->active_mm
;
7246 BUG_ON(cpu_online(smp_processor_id()));
7249 switch_mm(mm
, &init_mm
, current
);
7253 /* called under rq->lock with disabled interrupts */
7254 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
7256 struct rq
*rq
= cpu_rq(dead_cpu
);
7258 /* Must be exiting, otherwise would be on tasklist. */
7259 BUG_ON(!p
->exit_state
);
7261 /* Cannot have done final schedule yet: would have vanished. */
7262 BUG_ON(p
->state
== TASK_DEAD
);
7267 * Drop lock around migration; if someone else moves it,
7268 * that's OK. No task can be added to this CPU, so iteration is
7271 spin_unlock_irq(&rq
->lock
);
7272 move_task_off_dead_cpu(dead_cpu
, p
);
7273 spin_lock_irq(&rq
->lock
);
7278 /* release_task() removes task from tasklist, so we won't find dead tasks. */
7279 static void migrate_dead_tasks(unsigned int dead_cpu
)
7281 struct rq
*rq
= cpu_rq(dead_cpu
);
7282 struct task_struct
*next
;
7285 if (!rq
->nr_running
)
7287 update_rq_clock(rq
);
7288 next
= pick_next_task(rq
);
7291 next
->sched_class
->put_prev_task(rq
, next
);
7292 migrate_dead(dead_cpu
, next
);
7298 * remove the tasks which were accounted by rq from calc_load_tasks.
7300 static void calc_global_load_remove(struct rq
*rq
)
7302 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
7304 #endif /* CONFIG_HOTPLUG_CPU */
7306 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
7308 static struct ctl_table sd_ctl_dir
[] = {
7310 .procname
= "sched_domain",
7316 static struct ctl_table sd_ctl_root
[] = {
7318 .ctl_name
= CTL_KERN
,
7319 .procname
= "kernel",
7321 .child
= sd_ctl_dir
,
7326 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
7328 struct ctl_table
*entry
=
7329 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
7334 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
7336 struct ctl_table
*entry
;
7339 * In the intermediate directories, both the child directory and
7340 * procname are dynamically allocated and could fail but the mode
7341 * will always be set. In the lowest directory the names are
7342 * static strings and all have proc handlers.
7344 for (entry
= *tablep
; entry
->mode
; entry
++) {
7346 sd_free_ctl_entry(&entry
->child
);
7347 if (entry
->proc_handler
== NULL
)
7348 kfree(entry
->procname
);
7356 set_table_entry(struct ctl_table
*entry
,
7357 const char *procname
, void *data
, int maxlen
,
7358 mode_t mode
, proc_handler
*proc_handler
)
7360 entry
->procname
= procname
;
7362 entry
->maxlen
= maxlen
;
7364 entry
->proc_handler
= proc_handler
;
7367 static struct ctl_table
*
7368 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
7370 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
7375 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
7376 sizeof(long), 0644, proc_doulongvec_minmax
);
7377 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
7378 sizeof(long), 0644, proc_doulongvec_minmax
);
7379 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
7380 sizeof(int), 0644, proc_dointvec_minmax
);
7381 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
7382 sizeof(int), 0644, proc_dointvec_minmax
);
7383 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
7384 sizeof(int), 0644, proc_dointvec_minmax
);
7385 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
7386 sizeof(int), 0644, proc_dointvec_minmax
);
7387 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
7388 sizeof(int), 0644, proc_dointvec_minmax
);
7389 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
7390 sizeof(int), 0644, proc_dointvec_minmax
);
7391 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
7392 sizeof(int), 0644, proc_dointvec_minmax
);
7393 set_table_entry(&table
[9], "cache_nice_tries",
7394 &sd
->cache_nice_tries
,
7395 sizeof(int), 0644, proc_dointvec_minmax
);
7396 set_table_entry(&table
[10], "flags", &sd
->flags
,
7397 sizeof(int), 0644, proc_dointvec_minmax
);
7398 set_table_entry(&table
[11], "name", sd
->name
,
7399 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
7400 /* &table[12] is terminator */
7405 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
7407 struct ctl_table
*entry
, *table
;
7408 struct sched_domain
*sd
;
7409 int domain_num
= 0, i
;
7412 for_each_domain(cpu
, sd
)
7414 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
7419 for_each_domain(cpu
, sd
) {
7420 snprintf(buf
, 32, "domain%d", i
);
7421 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7423 entry
->child
= sd_alloc_ctl_domain_table(sd
);
7430 static struct ctl_table_header
*sd_sysctl_header
;
7431 static void register_sched_domain_sysctl(void)
7433 int i
, cpu_num
= num_online_cpus();
7434 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
7437 WARN_ON(sd_ctl_dir
[0].child
);
7438 sd_ctl_dir
[0].child
= entry
;
7443 for_each_online_cpu(i
) {
7444 snprintf(buf
, 32, "cpu%d", i
);
7445 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
7447 entry
->child
= sd_alloc_ctl_cpu_table(i
);
7451 WARN_ON(sd_sysctl_header
);
7452 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
7455 /* may be called multiple times per register */
7456 static void unregister_sched_domain_sysctl(void)
7458 if (sd_sysctl_header
)
7459 unregister_sysctl_table(sd_sysctl_header
);
7460 sd_sysctl_header
= NULL
;
7461 if (sd_ctl_dir
[0].child
)
7462 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
7465 static void register_sched_domain_sysctl(void)
7468 static void unregister_sched_domain_sysctl(void)
7473 static void set_rq_online(struct rq
*rq
)
7476 const struct sched_class
*class;
7478 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
7481 for_each_class(class) {
7482 if (class->rq_online
)
7483 class->rq_online(rq
);
7488 static void set_rq_offline(struct rq
*rq
)
7491 const struct sched_class
*class;
7493 for_each_class(class) {
7494 if (class->rq_offline
)
7495 class->rq_offline(rq
);
7498 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
7504 * migration_call - callback that gets triggered when a CPU is added.
7505 * Here we can start up the necessary migration thread for the new CPU.
7507 static int __cpuinit
7508 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
7510 struct task_struct
*p
;
7511 int cpu
= (long)hcpu
;
7512 unsigned long flags
;
7517 case CPU_UP_PREPARE
:
7518 case CPU_UP_PREPARE_FROZEN
:
7519 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
7522 kthread_bind(p
, cpu
);
7523 /* Must be high prio: stop_machine expects to yield to it. */
7524 rq
= task_rq_lock(p
, &flags
);
7525 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
7526 task_rq_unlock(rq
, &flags
);
7528 cpu_rq(cpu
)->migration_thread
= p
;
7532 case CPU_ONLINE_FROZEN
:
7533 /* Strictly unnecessary, as first user will wake it. */
7534 wake_up_process(cpu_rq(cpu
)->migration_thread
);
7536 /* Update our root-domain */
7538 spin_lock_irqsave(&rq
->lock
, flags
);
7539 rq
->calc_load_update
= calc_load_update
;
7540 rq
->calc_load_active
= 0;
7542 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7546 spin_unlock_irqrestore(&rq
->lock
, flags
);
7549 #ifdef CONFIG_HOTPLUG_CPU
7550 case CPU_UP_CANCELED
:
7551 case CPU_UP_CANCELED_FROZEN
:
7552 if (!cpu_rq(cpu
)->migration_thread
)
7554 /* Unbind it from offline cpu so it can run. Fall thru. */
7555 kthread_bind(cpu_rq(cpu
)->migration_thread
,
7556 cpumask_any(cpu_online_mask
));
7557 kthread_stop(cpu_rq(cpu
)->migration_thread
);
7558 put_task_struct(cpu_rq(cpu
)->migration_thread
);
7559 cpu_rq(cpu
)->migration_thread
= NULL
;
7563 case CPU_DEAD_FROZEN
:
7564 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7565 migrate_live_tasks(cpu
);
7567 kthread_stop(rq
->migration_thread
);
7568 put_task_struct(rq
->migration_thread
);
7569 rq
->migration_thread
= NULL
;
7570 /* Idle task back to normal (off runqueue, low prio) */
7571 spin_lock_irq(&rq
->lock
);
7572 update_rq_clock(rq
);
7573 deactivate_task(rq
, rq
->idle
, 0);
7574 rq
->idle
->static_prio
= MAX_PRIO
;
7575 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
7576 rq
->idle
->sched_class
= &idle_sched_class
;
7577 migrate_dead_tasks(cpu
);
7578 spin_unlock_irq(&rq
->lock
);
7580 migrate_nr_uninterruptible(rq
);
7581 BUG_ON(rq
->nr_running
!= 0);
7582 calc_global_load_remove(rq
);
7584 * No need to migrate the tasks: it was best-effort if
7585 * they didn't take sched_hotcpu_mutex. Just wake up
7588 spin_lock_irq(&rq
->lock
);
7589 while (!list_empty(&rq
->migration_queue
)) {
7590 struct migration_req
*req
;
7592 req
= list_entry(rq
->migration_queue
.next
,
7593 struct migration_req
, list
);
7594 list_del_init(&req
->list
);
7595 spin_unlock_irq(&rq
->lock
);
7596 complete(&req
->done
);
7597 spin_lock_irq(&rq
->lock
);
7599 spin_unlock_irq(&rq
->lock
);
7603 case CPU_DYING_FROZEN
:
7604 /* Update our root-domain */
7606 spin_lock_irqsave(&rq
->lock
, flags
);
7608 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
7611 spin_unlock_irqrestore(&rq
->lock
, flags
);
7619 * Register at high priority so that task migration (migrate_all_tasks)
7620 * happens before everything else. This has to be lower priority than
7621 * the notifier in the perf_counter subsystem, though.
7623 static struct notifier_block __cpuinitdata migration_notifier
= {
7624 .notifier_call
= migration_call
,
7628 static int __init
migration_init(void)
7630 void *cpu
= (void *)(long)smp_processor_id();
7633 /* Start one for the boot CPU: */
7634 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
7635 BUG_ON(err
== NOTIFY_BAD
);
7636 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
7637 register_cpu_notifier(&migration_notifier
);
7641 early_initcall(migration_init
);
7646 #ifdef CONFIG_SCHED_DEBUG
7648 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
7649 struct cpumask
*groupmask
)
7651 struct sched_group
*group
= sd
->groups
;
7654 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
7655 cpumask_clear(groupmask
);
7657 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
7659 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
7660 printk("does not load-balance\n");
7662 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
7667 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
7669 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
7670 printk(KERN_ERR
"ERROR: domain->span does not contain "
7673 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
7674 printk(KERN_ERR
"ERROR: domain->groups does not contain"
7678 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
7682 printk(KERN_ERR
"ERROR: group is NULL\n");
7686 if (!group
->__cpu_power
) {
7687 printk(KERN_CONT
"\n");
7688 printk(KERN_ERR
"ERROR: domain->cpu_power not "
7693 if (!cpumask_weight(sched_group_cpus(group
))) {
7694 printk(KERN_CONT
"\n");
7695 printk(KERN_ERR
"ERROR: empty group\n");
7699 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
7700 printk(KERN_CONT
"\n");
7701 printk(KERN_ERR
"ERROR: repeated CPUs\n");
7705 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
7707 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
7709 printk(KERN_CONT
" %s", str
);
7710 if (group
->__cpu_power
!= SCHED_LOAD_SCALE
) {
7711 printk(KERN_CONT
" (__cpu_power = %d)",
7712 group
->__cpu_power
);
7715 group
= group
->next
;
7716 } while (group
!= sd
->groups
);
7717 printk(KERN_CONT
"\n");
7719 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
7720 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
7723 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
7724 printk(KERN_ERR
"ERROR: parent span is not a superset "
7725 "of domain->span\n");
7729 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
7731 cpumask_var_t groupmask
;
7735 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
7739 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
7741 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
7742 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
7747 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
7754 free_cpumask_var(groupmask
);
7756 #else /* !CONFIG_SCHED_DEBUG */
7757 # define sched_domain_debug(sd, cpu) do { } while (0)
7758 #endif /* CONFIG_SCHED_DEBUG */
7760 static int sd_degenerate(struct sched_domain
*sd
)
7762 if (cpumask_weight(sched_domain_span(sd
)) == 1)
7765 /* Following flags need at least 2 groups */
7766 if (sd
->flags
& (SD_LOAD_BALANCE
|
7767 SD_BALANCE_NEWIDLE
|
7771 SD_SHARE_PKG_RESOURCES
)) {
7772 if (sd
->groups
!= sd
->groups
->next
)
7776 /* Following flags don't use groups */
7777 if (sd
->flags
& (SD_WAKE_IDLE
|
7786 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
7788 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
7790 if (sd_degenerate(parent
))
7793 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
7796 /* Does parent contain flags not in child? */
7797 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7798 if (cflags
& SD_WAKE_AFFINE
)
7799 pflags
&= ~SD_WAKE_BALANCE
;
7800 /* Flags needing groups don't count if only 1 group in parent */
7801 if (parent
->groups
== parent
->groups
->next
) {
7802 pflags
&= ~(SD_LOAD_BALANCE
|
7803 SD_BALANCE_NEWIDLE
|
7807 SD_SHARE_PKG_RESOURCES
);
7808 if (nr_node_ids
== 1)
7809 pflags
&= ~SD_SERIALIZE
;
7811 if (~cflags
& pflags
)
7817 static void free_rootdomain(struct root_domain
*rd
)
7819 cpupri_cleanup(&rd
->cpupri
);
7821 free_cpumask_var(rd
->rto_mask
);
7822 free_cpumask_var(rd
->online
);
7823 free_cpumask_var(rd
->span
);
7827 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7829 struct root_domain
*old_rd
= NULL
;
7830 unsigned long flags
;
7832 spin_lock_irqsave(&rq
->lock
, flags
);
7837 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
7840 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
7843 * If we dont want to free the old_rt yet then
7844 * set old_rd to NULL to skip the freeing later
7847 if (!atomic_dec_and_test(&old_rd
->refcount
))
7851 atomic_inc(&rd
->refcount
);
7854 cpumask_set_cpu(rq
->cpu
, rd
->span
);
7855 if (cpumask_test_cpu(rq
->cpu
, cpu_online_mask
))
7858 spin_unlock_irqrestore(&rq
->lock
, flags
);
7861 free_rootdomain(old_rd
);
7864 static int init_rootdomain(struct root_domain
*rd
, bool bootmem
)
7866 gfp_t gfp
= GFP_KERNEL
;
7868 memset(rd
, 0, sizeof(*rd
));
7873 if (!alloc_cpumask_var(&rd
->span
, gfp
))
7875 if (!alloc_cpumask_var(&rd
->online
, gfp
))
7877 if (!alloc_cpumask_var(&rd
->rto_mask
, gfp
))
7880 if (cpupri_init(&rd
->cpupri
, bootmem
) != 0)
7885 free_cpumask_var(rd
->rto_mask
);
7887 free_cpumask_var(rd
->online
);
7889 free_cpumask_var(rd
->span
);
7894 static void init_defrootdomain(void)
7896 init_rootdomain(&def_root_domain
, true);
7898 atomic_set(&def_root_domain
.refcount
, 1);
7901 static struct root_domain
*alloc_rootdomain(void)
7903 struct root_domain
*rd
;
7905 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
7909 if (init_rootdomain(rd
, false) != 0) {
7918 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7919 * hold the hotplug lock.
7922 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
7924 struct rq
*rq
= cpu_rq(cpu
);
7925 struct sched_domain
*tmp
;
7927 /* Remove the sched domains which do not contribute to scheduling. */
7928 for (tmp
= sd
; tmp
; ) {
7929 struct sched_domain
*parent
= tmp
->parent
;
7933 if (sd_parent_degenerate(tmp
, parent
)) {
7934 tmp
->parent
= parent
->parent
;
7936 parent
->parent
->child
= tmp
;
7941 if (sd
&& sd_degenerate(sd
)) {
7947 sched_domain_debug(sd
, cpu
);
7949 rq_attach_root(rq
, rd
);
7950 rcu_assign_pointer(rq
->sd
, sd
);
7953 /* cpus with isolated domains */
7954 static cpumask_var_t cpu_isolated_map
;
7956 /* Setup the mask of cpus configured for isolated domains */
7957 static int __init
isolated_cpu_setup(char *str
)
7959 cpulist_parse(str
, cpu_isolated_map
);
7963 __setup("isolcpus=", isolated_cpu_setup
);
7966 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7967 * to a function which identifies what group(along with sched group) a CPU
7968 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7969 * (due to the fact that we keep track of groups covered with a struct cpumask).
7971 * init_sched_build_groups will build a circular linked list of the groups
7972 * covered by the given span, and will set each group's ->cpumask correctly,
7973 * and ->cpu_power to 0.
7976 init_sched_build_groups(const struct cpumask
*span
,
7977 const struct cpumask
*cpu_map
,
7978 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
7979 struct sched_group
**sg
,
7980 struct cpumask
*tmpmask
),
7981 struct cpumask
*covered
, struct cpumask
*tmpmask
)
7983 struct sched_group
*first
= NULL
, *last
= NULL
;
7986 cpumask_clear(covered
);
7988 for_each_cpu(i
, span
) {
7989 struct sched_group
*sg
;
7990 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
7993 if (cpumask_test_cpu(i
, covered
))
7996 cpumask_clear(sched_group_cpus(sg
));
7997 sg
->__cpu_power
= 0;
7999 for_each_cpu(j
, span
) {
8000 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
8003 cpumask_set_cpu(j
, covered
);
8004 cpumask_set_cpu(j
, sched_group_cpus(sg
));
8015 #define SD_NODES_PER_DOMAIN 16
8020 * find_next_best_node - find the next node to include in a sched_domain
8021 * @node: node whose sched_domain we're building
8022 * @used_nodes: nodes already in the sched_domain
8024 * Find the next node to include in a given scheduling domain. Simply
8025 * finds the closest node not already in the @used_nodes map.
8027 * Should use nodemask_t.
8029 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
8031 int i
, n
, val
, min_val
, best_node
= 0;
8035 for (i
= 0; i
< nr_node_ids
; i
++) {
8036 /* Start at @node */
8037 n
= (node
+ i
) % nr_node_ids
;
8039 if (!nr_cpus_node(n
))
8042 /* Skip already used nodes */
8043 if (node_isset(n
, *used_nodes
))
8046 /* Simple min distance search */
8047 val
= node_distance(node
, n
);
8049 if (val
< min_val
) {
8055 node_set(best_node
, *used_nodes
);
8060 * sched_domain_node_span - get a cpumask for a node's sched_domain
8061 * @node: node whose cpumask we're constructing
8062 * @span: resulting cpumask
8064 * Given a node, construct a good cpumask for its sched_domain to span. It
8065 * should be one that prevents unnecessary balancing, but also spreads tasks
8068 static void sched_domain_node_span(int node
, struct cpumask
*span
)
8070 nodemask_t used_nodes
;
8073 cpumask_clear(span
);
8074 nodes_clear(used_nodes
);
8076 cpumask_or(span
, span
, cpumask_of_node(node
));
8077 node_set(node
, used_nodes
);
8079 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
8080 int next_node
= find_next_best_node(node
, &used_nodes
);
8082 cpumask_or(span
, span
, cpumask_of_node(next_node
));
8085 #endif /* CONFIG_NUMA */
8087 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
8090 * The cpus mask in sched_group and sched_domain hangs off the end.
8092 * ( See the the comments in include/linux/sched.h:struct sched_group
8093 * and struct sched_domain. )
8095 struct static_sched_group
{
8096 struct sched_group sg
;
8097 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
8100 struct static_sched_domain
{
8101 struct sched_domain sd
;
8102 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
8106 * SMT sched-domains:
8108 #ifdef CONFIG_SCHED_SMT
8109 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
8110 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_cpus
);
8113 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
8114 struct sched_group
**sg
, struct cpumask
*unused
)
8117 *sg
= &per_cpu(sched_group_cpus
, cpu
).sg
;
8120 #endif /* CONFIG_SCHED_SMT */
8123 * multi-core sched-domains:
8125 #ifdef CONFIG_SCHED_MC
8126 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
8127 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
8128 #endif /* CONFIG_SCHED_MC */
8130 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
8132 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8133 struct sched_group
**sg
, struct cpumask
*mask
)
8137 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8138 group
= cpumask_first(mask
);
8140 *sg
= &per_cpu(sched_group_core
, group
).sg
;
8143 #elif defined(CONFIG_SCHED_MC)
8145 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
8146 struct sched_group
**sg
, struct cpumask
*unused
)
8149 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
8154 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
8155 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
8158 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
8159 struct sched_group
**sg
, struct cpumask
*mask
)
8162 #ifdef CONFIG_SCHED_MC
8163 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
8164 group
= cpumask_first(mask
);
8165 #elif defined(CONFIG_SCHED_SMT)
8166 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
8167 group
= cpumask_first(mask
);
8172 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
8178 * The init_sched_build_groups can't handle what we want to do with node
8179 * groups, so roll our own. Now each node has its own list of groups which
8180 * gets dynamically allocated.
8182 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
8183 static struct sched_group
***sched_group_nodes_bycpu
;
8185 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
8186 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
8188 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
8189 struct sched_group
**sg
,
8190 struct cpumask
*nodemask
)
8194 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
8195 group
= cpumask_first(nodemask
);
8198 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
8202 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
8204 struct sched_group
*sg
= group_head
;
8210 for_each_cpu(j
, sched_group_cpus(sg
)) {
8211 struct sched_domain
*sd
;
8213 sd
= &per_cpu(phys_domains
, j
).sd
;
8214 if (j
!= group_first_cpu(sd
->groups
)) {
8216 * Only add "power" once for each
8222 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
8225 } while (sg
!= group_head
);
8227 #endif /* CONFIG_NUMA */
8230 /* Free memory allocated for various sched_group structures */
8231 static void free_sched_groups(const struct cpumask
*cpu_map
,
8232 struct cpumask
*nodemask
)
8236 for_each_cpu(cpu
, cpu_map
) {
8237 struct sched_group
**sched_group_nodes
8238 = sched_group_nodes_bycpu
[cpu
];
8240 if (!sched_group_nodes
)
8243 for (i
= 0; i
< nr_node_ids
; i
++) {
8244 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
8246 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8247 if (cpumask_empty(nodemask
))
8257 if (oldsg
!= sched_group_nodes
[i
])
8260 kfree(sched_group_nodes
);
8261 sched_group_nodes_bycpu
[cpu
] = NULL
;
8264 #else /* !CONFIG_NUMA */
8265 static void free_sched_groups(const struct cpumask
*cpu_map
,
8266 struct cpumask
*nodemask
)
8269 #endif /* CONFIG_NUMA */
8272 * Initialize sched groups cpu_power.
8274 * cpu_power indicates the capacity of sched group, which is used while
8275 * distributing the load between different sched groups in a sched domain.
8276 * Typically cpu_power for all the groups in a sched domain will be same unless
8277 * there are asymmetries in the topology. If there are asymmetries, group
8278 * having more cpu_power will pickup more load compared to the group having
8281 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
8282 * the maximum number of tasks a group can handle in the presence of other idle
8283 * or lightly loaded groups in the same sched domain.
8285 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
8287 struct sched_domain
*child
;
8288 struct sched_group
*group
;
8290 WARN_ON(!sd
|| !sd
->groups
);
8292 if (cpu
!= group_first_cpu(sd
->groups
))
8297 sd
->groups
->__cpu_power
= 0;
8300 * For perf policy, if the groups in child domain share resources
8301 * (for example cores sharing some portions of the cache hierarchy
8302 * or SMT), then set this domain groups cpu_power such that each group
8303 * can handle only one task, when there are other idle groups in the
8304 * same sched domain.
8306 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
8308 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
8309 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
8314 * add cpu_power of each child group to this groups cpu_power
8316 group
= child
->groups
;
8318 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
8319 group
= group
->next
;
8320 } while (group
!= child
->groups
);
8324 * Initializers for schedule domains
8325 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
8328 #ifdef CONFIG_SCHED_DEBUG
8329 # define SD_INIT_NAME(sd, type) sd->name = #type
8331 # define SD_INIT_NAME(sd, type) do { } while (0)
8334 #define SD_INIT(sd, type) sd_init_##type(sd)
8336 #define SD_INIT_FUNC(type) \
8337 static noinline void sd_init_##type(struct sched_domain *sd) \
8339 memset(sd, 0, sizeof(*sd)); \
8340 *sd = SD_##type##_INIT; \
8341 sd->level = SD_LV_##type; \
8342 SD_INIT_NAME(sd, type); \
8347 SD_INIT_FUNC(ALLNODES
)
8350 #ifdef CONFIG_SCHED_SMT
8351 SD_INIT_FUNC(SIBLING
)
8353 #ifdef CONFIG_SCHED_MC
8357 static int default_relax_domain_level
= -1;
8359 static int __init
setup_relax_domain_level(char *str
)
8363 val
= simple_strtoul(str
, NULL
, 0);
8364 if (val
< SD_LV_MAX
)
8365 default_relax_domain_level
= val
;
8369 __setup("relax_domain_level=", setup_relax_domain_level
);
8371 static void set_domain_attribute(struct sched_domain
*sd
,
8372 struct sched_domain_attr
*attr
)
8376 if (!attr
|| attr
->relax_domain_level
< 0) {
8377 if (default_relax_domain_level
< 0)
8380 request
= default_relax_domain_level
;
8382 request
= attr
->relax_domain_level
;
8383 if (request
< sd
->level
) {
8384 /* turn off idle balance on this domain */
8385 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
8387 /* turn on idle balance on this domain */
8388 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
8393 * Build sched domains for a given set of cpus and attach the sched domains
8394 * to the individual cpus
8396 static int __build_sched_domains(const struct cpumask
*cpu_map
,
8397 struct sched_domain_attr
*attr
)
8399 int i
, err
= -ENOMEM
;
8400 struct root_domain
*rd
;
8401 cpumask_var_t nodemask
, this_sibling_map
, this_core_map
, send_covered
,
8404 cpumask_var_t domainspan
, covered
, notcovered
;
8405 struct sched_group
**sched_group_nodes
= NULL
;
8406 int sd_allnodes
= 0;
8408 if (!alloc_cpumask_var(&domainspan
, GFP_KERNEL
))
8410 if (!alloc_cpumask_var(&covered
, GFP_KERNEL
))
8411 goto free_domainspan
;
8412 if (!alloc_cpumask_var(¬covered
, GFP_KERNEL
))
8416 if (!alloc_cpumask_var(&nodemask
, GFP_KERNEL
))
8417 goto free_notcovered
;
8418 if (!alloc_cpumask_var(&this_sibling_map
, GFP_KERNEL
))
8420 if (!alloc_cpumask_var(&this_core_map
, GFP_KERNEL
))
8421 goto free_this_sibling_map
;
8422 if (!alloc_cpumask_var(&send_covered
, GFP_KERNEL
))
8423 goto free_this_core_map
;
8424 if (!alloc_cpumask_var(&tmpmask
, GFP_KERNEL
))
8425 goto free_send_covered
;
8429 * Allocate the per-node list of sched groups
8431 sched_group_nodes
= kcalloc(nr_node_ids
, sizeof(struct sched_group
*),
8433 if (!sched_group_nodes
) {
8434 printk(KERN_WARNING
"Can not alloc sched group node list\n");
8439 rd
= alloc_rootdomain();
8441 printk(KERN_WARNING
"Cannot alloc root domain\n");
8442 goto free_sched_groups
;
8446 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = sched_group_nodes
;
8450 * Set up domains for cpus specified by the cpu_map.
8452 for_each_cpu(i
, cpu_map
) {
8453 struct sched_domain
*sd
= NULL
, *p
;
8455 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(i
)), cpu_map
);
8458 if (cpumask_weight(cpu_map
) >
8459 SD_NODES_PER_DOMAIN
*cpumask_weight(nodemask
)) {
8460 sd
= &per_cpu(allnodes_domains
, i
).sd
;
8461 SD_INIT(sd
, ALLNODES
);
8462 set_domain_attribute(sd
, attr
);
8463 cpumask_copy(sched_domain_span(sd
), cpu_map
);
8464 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8470 sd
= &per_cpu(node_domains
, i
).sd
;
8472 set_domain_attribute(sd
, attr
);
8473 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
8477 cpumask_and(sched_domain_span(sd
),
8478 sched_domain_span(sd
), cpu_map
);
8482 sd
= &per_cpu(phys_domains
, i
).sd
;
8484 set_domain_attribute(sd
, attr
);
8485 cpumask_copy(sched_domain_span(sd
), nodemask
);
8489 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8491 #ifdef CONFIG_SCHED_MC
8493 sd
= &per_cpu(core_domains
, i
).sd
;
8495 set_domain_attribute(sd
, attr
);
8496 cpumask_and(sched_domain_span(sd
), cpu_map
,
8497 cpu_coregroup_mask(i
));
8500 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8503 #ifdef CONFIG_SCHED_SMT
8505 sd
= &per_cpu(cpu_domains
, i
).sd
;
8506 SD_INIT(sd
, SIBLING
);
8507 set_domain_attribute(sd
, attr
);
8508 cpumask_and(sched_domain_span(sd
),
8509 topology_thread_cpumask(i
), cpu_map
);
8512 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
8516 #ifdef CONFIG_SCHED_SMT
8517 /* Set up CPU (sibling) groups */
8518 for_each_cpu(i
, cpu_map
) {
8519 cpumask_and(this_sibling_map
,
8520 topology_thread_cpumask(i
), cpu_map
);
8521 if (i
!= cpumask_first(this_sibling_map
))
8524 init_sched_build_groups(this_sibling_map
, cpu_map
,
8526 send_covered
, tmpmask
);
8530 #ifdef CONFIG_SCHED_MC
8531 /* Set up multi-core groups */
8532 for_each_cpu(i
, cpu_map
) {
8533 cpumask_and(this_core_map
, cpu_coregroup_mask(i
), cpu_map
);
8534 if (i
!= cpumask_first(this_core_map
))
8537 init_sched_build_groups(this_core_map
, cpu_map
,
8539 send_covered
, tmpmask
);
8543 /* Set up physical groups */
8544 for (i
= 0; i
< nr_node_ids
; i
++) {
8545 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8546 if (cpumask_empty(nodemask
))
8549 init_sched_build_groups(nodemask
, cpu_map
,
8551 send_covered
, tmpmask
);
8555 /* Set up node groups */
8557 init_sched_build_groups(cpu_map
, cpu_map
,
8558 &cpu_to_allnodes_group
,
8559 send_covered
, tmpmask
);
8562 for (i
= 0; i
< nr_node_ids
; i
++) {
8563 /* Set up node groups */
8564 struct sched_group
*sg
, *prev
;
8567 cpumask_clear(covered
);
8568 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
8569 if (cpumask_empty(nodemask
)) {
8570 sched_group_nodes
[i
] = NULL
;
8574 sched_domain_node_span(i
, domainspan
);
8575 cpumask_and(domainspan
, domainspan
, cpu_map
);
8577 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
8580 printk(KERN_WARNING
"Can not alloc domain group for "
8584 sched_group_nodes
[i
] = sg
;
8585 for_each_cpu(j
, nodemask
) {
8586 struct sched_domain
*sd
;
8588 sd
= &per_cpu(node_domains
, j
).sd
;
8591 sg
->__cpu_power
= 0;
8592 cpumask_copy(sched_group_cpus(sg
), nodemask
);
8594 cpumask_or(covered
, covered
, nodemask
);
8597 for (j
= 0; j
< nr_node_ids
; j
++) {
8598 int n
= (i
+ j
) % nr_node_ids
;
8600 cpumask_complement(notcovered
, covered
);
8601 cpumask_and(tmpmask
, notcovered
, cpu_map
);
8602 cpumask_and(tmpmask
, tmpmask
, domainspan
);
8603 if (cpumask_empty(tmpmask
))
8606 cpumask_and(tmpmask
, tmpmask
, cpumask_of_node(n
));
8607 if (cpumask_empty(tmpmask
))
8610 sg
= kmalloc_node(sizeof(struct sched_group
) +
8615 "Can not alloc domain group for node %d\n", j
);
8618 sg
->__cpu_power
= 0;
8619 cpumask_copy(sched_group_cpus(sg
), tmpmask
);
8620 sg
->next
= prev
->next
;
8621 cpumask_or(covered
, covered
, tmpmask
);
8628 /* Calculate CPU power for physical packages and nodes */
8629 #ifdef CONFIG_SCHED_SMT
8630 for_each_cpu(i
, cpu_map
) {
8631 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
).sd
;
8633 init_sched_groups_power(i
, sd
);
8636 #ifdef CONFIG_SCHED_MC
8637 for_each_cpu(i
, cpu_map
) {
8638 struct sched_domain
*sd
= &per_cpu(core_domains
, i
).sd
;
8640 init_sched_groups_power(i
, sd
);
8644 for_each_cpu(i
, cpu_map
) {
8645 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
).sd
;
8647 init_sched_groups_power(i
, sd
);
8651 for (i
= 0; i
< nr_node_ids
; i
++)
8652 init_numa_sched_groups_power(sched_group_nodes
[i
]);
8655 struct sched_group
*sg
;
8657 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
8659 init_numa_sched_groups_power(sg
);
8663 /* Attach the domains */
8664 for_each_cpu(i
, cpu_map
) {
8665 struct sched_domain
*sd
;
8666 #ifdef CONFIG_SCHED_SMT
8667 sd
= &per_cpu(cpu_domains
, i
).sd
;
8668 #elif defined(CONFIG_SCHED_MC)
8669 sd
= &per_cpu(core_domains
, i
).sd
;
8671 sd
= &per_cpu(phys_domains
, i
).sd
;
8673 cpu_attach_domain(sd
, rd
, i
);
8679 free_cpumask_var(tmpmask
);
8681 free_cpumask_var(send_covered
);
8683 free_cpumask_var(this_core_map
);
8684 free_this_sibling_map
:
8685 free_cpumask_var(this_sibling_map
);
8687 free_cpumask_var(nodemask
);
8690 free_cpumask_var(notcovered
);
8692 free_cpumask_var(covered
);
8694 free_cpumask_var(domainspan
);
8701 kfree(sched_group_nodes
);
8707 free_sched_groups(cpu_map
, tmpmask
);
8708 free_rootdomain(rd
);
8713 static int build_sched_domains(const struct cpumask
*cpu_map
)
8715 return __build_sched_domains(cpu_map
, NULL
);
8718 static struct cpumask
*doms_cur
; /* current sched domains */
8719 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
8720 static struct sched_domain_attr
*dattr_cur
;
8721 /* attribues of custom domains in 'doms_cur' */
8724 * Special case: If a kmalloc of a doms_cur partition (array of
8725 * cpumask) fails, then fallback to a single sched domain,
8726 * as determined by the single cpumask fallback_doms.
8728 static cpumask_var_t fallback_doms
;
8731 * arch_update_cpu_topology lets virtualized architectures update the
8732 * cpu core maps. It is supposed to return 1 if the topology changed
8733 * or 0 if it stayed the same.
8735 int __attribute__((weak
)) arch_update_cpu_topology(void)
8741 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8742 * For now this just excludes isolated cpus, but could be used to
8743 * exclude other special cases in the future.
8745 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
8749 arch_update_cpu_topology();
8751 doms_cur
= kmalloc(cpumask_size(), GFP_KERNEL
);
8753 doms_cur
= fallback_doms
;
8754 cpumask_andnot(doms_cur
, cpu_map
, cpu_isolated_map
);
8756 err
= build_sched_domains(doms_cur
);
8757 register_sched_domain_sysctl();
8762 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
8763 struct cpumask
*tmpmask
)
8765 free_sched_groups(cpu_map
, tmpmask
);
8769 * Detach sched domains from a group of cpus specified in cpu_map
8770 * These cpus will now be attached to the NULL domain
8772 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
8774 /* Save because hotplug lock held. */
8775 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
8778 for_each_cpu(i
, cpu_map
)
8779 cpu_attach_domain(NULL
, &def_root_domain
, i
);
8780 synchronize_sched();
8781 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
8784 /* handle null as "default" */
8785 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
8786 struct sched_domain_attr
*new, int idx_new
)
8788 struct sched_domain_attr tmp
;
8795 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
8796 new ? (new + idx_new
) : &tmp
,
8797 sizeof(struct sched_domain_attr
));
8801 * Partition sched domains as specified by the 'ndoms_new'
8802 * cpumasks in the array doms_new[] of cpumasks. This compares
8803 * doms_new[] to the current sched domain partitioning, doms_cur[].
8804 * It destroys each deleted domain and builds each new domain.
8806 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8807 * The masks don't intersect (don't overlap.) We should setup one
8808 * sched domain for each mask. CPUs not in any of the cpumasks will
8809 * not be load balanced. If the same cpumask appears both in the
8810 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8813 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8814 * ownership of it and will kfree it when done with it. If the caller
8815 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8816 * ndoms_new == 1, and partition_sched_domains() will fallback to
8817 * the single partition 'fallback_doms', it also forces the domains
8820 * If doms_new == NULL it will be replaced with cpu_online_mask.
8821 * ndoms_new == 0 is a special case for destroying existing domains,
8822 * and it will not create the default domain.
8824 * Call with hotplug lock held
8826 /* FIXME: Change to struct cpumask *doms_new[] */
8827 void partition_sched_domains(int ndoms_new
, struct cpumask
*doms_new
,
8828 struct sched_domain_attr
*dattr_new
)
8833 mutex_lock(&sched_domains_mutex
);
8835 /* always unregister in case we don't destroy any domains */
8836 unregister_sched_domain_sysctl();
8838 /* Let architecture update cpu core mappings. */
8839 new_topology
= arch_update_cpu_topology();
8841 n
= doms_new
? ndoms_new
: 0;
8843 /* Destroy deleted domains */
8844 for (i
= 0; i
< ndoms_cur
; i
++) {
8845 for (j
= 0; j
< n
&& !new_topology
; j
++) {
8846 if (cpumask_equal(&doms_cur
[i
], &doms_new
[j
])
8847 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
8850 /* no match - a current sched domain not in new doms_new[] */
8851 detach_destroy_domains(doms_cur
+ i
);
8856 if (doms_new
== NULL
) {
8858 doms_new
= fallback_doms
;
8859 cpumask_andnot(&doms_new
[0], cpu_online_mask
, cpu_isolated_map
);
8860 WARN_ON_ONCE(dattr_new
);
8863 /* Build new domains */
8864 for (i
= 0; i
< ndoms_new
; i
++) {
8865 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
8866 if (cpumask_equal(&doms_new
[i
], &doms_cur
[j
])
8867 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
8870 /* no match - add a new doms_new */
8871 __build_sched_domains(doms_new
+ i
,
8872 dattr_new
? dattr_new
+ i
: NULL
);
8877 /* Remember the new sched domains */
8878 if (doms_cur
!= fallback_doms
)
8880 kfree(dattr_cur
); /* kfree(NULL) is safe */
8881 doms_cur
= doms_new
;
8882 dattr_cur
= dattr_new
;
8883 ndoms_cur
= ndoms_new
;
8885 register_sched_domain_sysctl();
8887 mutex_unlock(&sched_domains_mutex
);
8890 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8891 static void arch_reinit_sched_domains(void)
8895 /* Destroy domains first to force the rebuild */
8896 partition_sched_domains(0, NULL
, NULL
);
8898 rebuild_sched_domains();
8902 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
8904 unsigned int level
= 0;
8906 if (sscanf(buf
, "%u", &level
) != 1)
8910 * level is always be positive so don't check for
8911 * level < POWERSAVINGS_BALANCE_NONE which is 0
8912 * What happens on 0 or 1 byte write,
8913 * need to check for count as well?
8916 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
8920 sched_smt_power_savings
= level
;
8922 sched_mc_power_savings
= level
;
8924 arch_reinit_sched_domains();
8929 #ifdef CONFIG_SCHED_MC
8930 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
8933 return sprintf(page
, "%u\n", sched_mc_power_savings
);
8935 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
8936 const char *buf
, size_t count
)
8938 return sched_power_savings_store(buf
, count
, 0);
8940 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
8941 sched_mc_power_savings_show
,
8942 sched_mc_power_savings_store
);
8945 #ifdef CONFIG_SCHED_SMT
8946 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
8949 return sprintf(page
, "%u\n", sched_smt_power_savings
);
8951 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
8952 const char *buf
, size_t count
)
8954 return sched_power_savings_store(buf
, count
, 1);
8956 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
8957 sched_smt_power_savings_show
,
8958 sched_smt_power_savings_store
);
8961 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
8965 #ifdef CONFIG_SCHED_SMT
8967 err
= sysfs_create_file(&cls
->kset
.kobj
,
8968 &attr_sched_smt_power_savings
.attr
);
8970 #ifdef CONFIG_SCHED_MC
8971 if (!err
&& mc_capable())
8972 err
= sysfs_create_file(&cls
->kset
.kobj
,
8973 &attr_sched_mc_power_savings
.attr
);
8977 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
8979 #ifndef CONFIG_CPUSETS
8981 * Add online and remove offline CPUs from the scheduler domains.
8982 * When cpusets are enabled they take over this function.
8984 static int update_sched_domains(struct notifier_block
*nfb
,
8985 unsigned long action
, void *hcpu
)
8989 case CPU_ONLINE_FROZEN
:
8991 case CPU_DEAD_FROZEN
:
8992 partition_sched_domains(1, NULL
, NULL
);
9001 static int update_runtime(struct notifier_block
*nfb
,
9002 unsigned long action
, void *hcpu
)
9004 int cpu
= (int)(long)hcpu
;
9007 case CPU_DOWN_PREPARE
:
9008 case CPU_DOWN_PREPARE_FROZEN
:
9009 disable_runtime(cpu_rq(cpu
));
9012 case CPU_DOWN_FAILED
:
9013 case CPU_DOWN_FAILED_FROZEN
:
9015 case CPU_ONLINE_FROZEN
:
9016 enable_runtime(cpu_rq(cpu
));
9024 void __init
sched_init_smp(void)
9026 cpumask_var_t non_isolated_cpus
;
9028 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
9030 #if defined(CONFIG_NUMA)
9031 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
9033 BUG_ON(sched_group_nodes_bycpu
== NULL
);
9036 mutex_lock(&sched_domains_mutex
);
9037 arch_init_sched_domains(cpu_online_mask
);
9038 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
9039 if (cpumask_empty(non_isolated_cpus
))
9040 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
9041 mutex_unlock(&sched_domains_mutex
);
9044 #ifndef CONFIG_CPUSETS
9045 /* XXX: Theoretical race here - CPU may be hotplugged now */
9046 hotcpu_notifier(update_sched_domains
, 0);
9049 /* RT runtime code needs to handle some hotplug events */
9050 hotcpu_notifier(update_runtime
, 0);
9054 /* Move init over to a non-isolated CPU */
9055 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
9057 sched_init_granularity();
9058 free_cpumask_var(non_isolated_cpus
);
9060 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
9061 init_sched_rt_class();
9064 void __init
sched_init_smp(void)
9066 sched_init_granularity();
9068 #endif /* CONFIG_SMP */
9070 const_debug
unsigned int sysctl_timer_migration
= 1;
9072 int in_sched_functions(unsigned long addr
)
9074 return in_lock_functions(addr
) ||
9075 (addr
>= (unsigned long)__sched_text_start
9076 && addr
< (unsigned long)__sched_text_end
);
9079 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
9081 cfs_rq
->tasks_timeline
= RB_ROOT
;
9082 INIT_LIST_HEAD(&cfs_rq
->tasks
);
9083 #ifdef CONFIG_FAIR_GROUP_SCHED
9086 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
9089 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
9091 struct rt_prio_array
*array
;
9094 array
= &rt_rq
->active
;
9095 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
9096 INIT_LIST_HEAD(array
->queue
+ i
);
9097 __clear_bit(i
, array
->bitmap
);
9099 /* delimiter for bitsearch: */
9100 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
9102 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
9103 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
9105 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
9109 rt_rq
->rt_nr_migratory
= 0;
9110 rt_rq
->overloaded
= 0;
9111 plist_head_init(&rq
->rt
.pushable_tasks
, &rq
->lock
);
9115 rt_rq
->rt_throttled
= 0;
9116 rt_rq
->rt_runtime
= 0;
9117 spin_lock_init(&rt_rq
->rt_runtime_lock
);
9119 #ifdef CONFIG_RT_GROUP_SCHED
9120 rt_rq
->rt_nr_boosted
= 0;
9125 #ifdef CONFIG_FAIR_GROUP_SCHED
9126 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
9127 struct sched_entity
*se
, int cpu
, int add
,
9128 struct sched_entity
*parent
)
9130 struct rq
*rq
= cpu_rq(cpu
);
9131 tg
->cfs_rq
[cpu
] = cfs_rq
;
9132 init_cfs_rq(cfs_rq
, rq
);
9135 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
9138 /* se could be NULL for init_task_group */
9143 se
->cfs_rq
= &rq
->cfs
;
9145 se
->cfs_rq
= parent
->my_q
;
9148 se
->load
.weight
= tg
->shares
;
9149 se
->load
.inv_weight
= 0;
9150 se
->parent
= parent
;
9154 #ifdef CONFIG_RT_GROUP_SCHED
9155 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
9156 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
9157 struct sched_rt_entity
*parent
)
9159 struct rq
*rq
= cpu_rq(cpu
);
9161 tg
->rt_rq
[cpu
] = rt_rq
;
9162 init_rt_rq(rt_rq
, rq
);
9164 rt_rq
->rt_se
= rt_se
;
9165 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9167 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
9169 tg
->rt_se
[cpu
] = rt_se
;
9174 rt_se
->rt_rq
= &rq
->rt
;
9176 rt_se
->rt_rq
= parent
->my_q
;
9178 rt_se
->my_q
= rt_rq
;
9179 rt_se
->parent
= parent
;
9180 INIT_LIST_HEAD(&rt_se
->run_list
);
9184 void __init
sched_init(void)
9187 unsigned long alloc_size
= 0, ptr
;
9189 #ifdef CONFIG_FAIR_GROUP_SCHED
9190 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9192 #ifdef CONFIG_RT_GROUP_SCHED
9193 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
9195 #ifdef CONFIG_USER_SCHED
9198 #ifdef CONFIG_CPUMASK_OFFSTACK
9199 alloc_size
+= num_possible_cpus() * cpumask_size();
9202 * As sched_init() is called before page_alloc is setup,
9203 * we use alloc_bootmem().
9206 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
9208 #ifdef CONFIG_FAIR_GROUP_SCHED
9209 init_task_group
.se
= (struct sched_entity
**)ptr
;
9210 ptr
+= nr_cpu_ids
* sizeof(void **);
9212 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9213 ptr
+= nr_cpu_ids
* sizeof(void **);
9215 #ifdef CONFIG_USER_SCHED
9216 root_task_group
.se
= (struct sched_entity
**)ptr
;
9217 ptr
+= nr_cpu_ids
* sizeof(void **);
9219 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
9220 ptr
+= nr_cpu_ids
* sizeof(void **);
9221 #endif /* CONFIG_USER_SCHED */
9222 #endif /* CONFIG_FAIR_GROUP_SCHED */
9223 #ifdef CONFIG_RT_GROUP_SCHED
9224 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9225 ptr
+= nr_cpu_ids
* sizeof(void **);
9227 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9228 ptr
+= nr_cpu_ids
* sizeof(void **);
9230 #ifdef CONFIG_USER_SCHED
9231 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
9232 ptr
+= nr_cpu_ids
* sizeof(void **);
9234 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
9235 ptr
+= nr_cpu_ids
* sizeof(void **);
9236 #endif /* CONFIG_USER_SCHED */
9237 #endif /* CONFIG_RT_GROUP_SCHED */
9238 #ifdef CONFIG_CPUMASK_OFFSTACK
9239 for_each_possible_cpu(i
) {
9240 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
9241 ptr
+= cpumask_size();
9243 #endif /* CONFIG_CPUMASK_OFFSTACK */
9247 init_defrootdomain();
9250 init_rt_bandwidth(&def_rt_bandwidth
,
9251 global_rt_period(), global_rt_runtime());
9253 #ifdef CONFIG_RT_GROUP_SCHED
9254 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
9255 global_rt_period(), global_rt_runtime());
9256 #ifdef CONFIG_USER_SCHED
9257 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
9258 global_rt_period(), RUNTIME_INF
);
9259 #endif /* CONFIG_USER_SCHED */
9260 #endif /* CONFIG_RT_GROUP_SCHED */
9262 #ifdef CONFIG_GROUP_SCHED
9263 list_add(&init_task_group
.list
, &task_groups
);
9264 INIT_LIST_HEAD(&init_task_group
.children
);
9266 #ifdef CONFIG_USER_SCHED
9267 INIT_LIST_HEAD(&root_task_group
.children
);
9268 init_task_group
.parent
= &root_task_group
;
9269 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
9270 #endif /* CONFIG_USER_SCHED */
9271 #endif /* CONFIG_GROUP_SCHED */
9273 for_each_possible_cpu(i
) {
9277 spin_lock_init(&rq
->lock
);
9279 rq
->calc_load_active
= 0;
9280 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
9281 init_cfs_rq(&rq
->cfs
, rq
);
9282 init_rt_rq(&rq
->rt
, rq
);
9283 #ifdef CONFIG_FAIR_GROUP_SCHED
9284 init_task_group
.shares
= init_task_group_load
;
9285 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
9286 #ifdef CONFIG_CGROUP_SCHED
9288 * How much cpu bandwidth does init_task_group get?
9290 * In case of task-groups formed thr' the cgroup filesystem, it
9291 * gets 100% of the cpu resources in the system. This overall
9292 * system cpu resource is divided among the tasks of
9293 * init_task_group and its child task-groups in a fair manner,
9294 * based on each entity's (task or task-group's) weight
9295 * (se->load.weight).
9297 * In other words, if init_task_group has 10 tasks of weight
9298 * 1024) and two child groups A0 and A1 (of weight 1024 each),
9299 * then A0's share of the cpu resource is:
9301 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
9303 * We achieve this by letting init_task_group's tasks sit
9304 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
9306 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
9307 #elif defined CONFIG_USER_SCHED
9308 root_task_group
.shares
= NICE_0_LOAD
;
9309 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
9311 * In case of task-groups formed thr' the user id of tasks,
9312 * init_task_group represents tasks belonging to root user.
9313 * Hence it forms a sibling of all subsequent groups formed.
9314 * In this case, init_task_group gets only a fraction of overall
9315 * system cpu resource, based on the weight assigned to root
9316 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
9317 * by letting tasks of init_task_group sit in a separate cfs_rq
9318 * (init_cfs_rq) and having one entity represent this group of
9319 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
9321 init_tg_cfs_entry(&init_task_group
,
9322 &per_cpu(init_cfs_rq
, i
),
9323 &per_cpu(init_sched_entity
, i
), i
, 1,
9324 root_task_group
.se
[i
]);
9327 #endif /* CONFIG_FAIR_GROUP_SCHED */
9329 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
9330 #ifdef CONFIG_RT_GROUP_SCHED
9331 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
9332 #ifdef CONFIG_CGROUP_SCHED
9333 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
9334 #elif defined CONFIG_USER_SCHED
9335 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
9336 init_tg_rt_entry(&init_task_group
,
9337 &per_cpu(init_rt_rq
, i
),
9338 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
9339 root_task_group
.rt_se
[i
]);
9343 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
9344 rq
->cpu_load
[j
] = 0;
9348 rq
->active_balance
= 0;
9349 rq
->next_balance
= jiffies
;
9353 rq
->migration_thread
= NULL
;
9354 INIT_LIST_HEAD(&rq
->migration_queue
);
9355 rq_attach_root(rq
, &def_root_domain
);
9358 atomic_set(&rq
->nr_iowait
, 0);
9361 set_load_weight(&init_task
);
9363 #ifdef CONFIG_PREEMPT_NOTIFIERS
9364 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
9368 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
9371 #ifdef CONFIG_RT_MUTEXES
9372 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
9376 * The boot idle thread does lazy MMU switching as well:
9378 atomic_inc(&init_mm
.mm_count
);
9379 enter_lazy_tlb(&init_mm
, current
);
9382 * Make us the idle thread. Technically, schedule() should not be
9383 * called from this thread, however somewhere below it might be,
9384 * but because we are the idle thread, we just pick up running again
9385 * when this runqueue becomes "idle".
9387 init_idle(current
, smp_processor_id());
9389 calc_load_update
= jiffies
+ LOAD_FREQ
;
9392 * During early bootup we pretend to be a normal task:
9394 current
->sched_class
= &fair_sched_class
;
9396 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9397 alloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
9400 alloc_cpumask_var(&nohz
.cpu_mask
, GFP_NOWAIT
);
9401 alloc_cpumask_var(&nohz
.ilb_grp_nohz_mask
, GFP_NOWAIT
);
9403 alloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
9406 perf_counter_init();
9408 scheduler_running
= 1;
9411 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9412 void __might_sleep(char *file
, int line
)
9415 static unsigned long prev_jiffy
; /* ratelimiting */
9417 if ((!in_atomic() && !irqs_disabled()) ||
9418 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
9420 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
9422 prev_jiffy
= jiffies
;
9425 "BUG: sleeping function called from invalid context at %s:%d\n",
9428 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9429 in_atomic(), irqs_disabled(),
9430 current
->pid
, current
->comm
);
9432 debug_show_held_locks(current
);
9433 if (irqs_disabled())
9434 print_irqtrace_events(current
);
9438 EXPORT_SYMBOL(__might_sleep
);
9441 #ifdef CONFIG_MAGIC_SYSRQ
9442 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
9446 update_rq_clock(rq
);
9447 on_rq
= p
->se
.on_rq
;
9449 deactivate_task(rq
, p
, 0);
9450 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
9452 activate_task(rq
, p
, 0);
9453 resched_task(rq
->curr
);
9457 void normalize_rt_tasks(void)
9459 struct task_struct
*g
, *p
;
9460 unsigned long flags
;
9463 read_lock_irqsave(&tasklist_lock
, flags
);
9464 do_each_thread(g
, p
) {
9466 * Only normalize user tasks:
9471 p
->se
.exec_start
= 0;
9472 #ifdef CONFIG_SCHEDSTATS
9473 p
->se
.wait_start
= 0;
9474 p
->se
.sleep_start
= 0;
9475 p
->se
.block_start
= 0;
9480 * Renice negative nice level userspace
9483 if (TASK_NICE(p
) < 0 && p
->mm
)
9484 set_user_nice(p
, 0);
9488 spin_lock(&p
->pi_lock
);
9489 rq
= __task_rq_lock(p
);
9491 normalize_task(rq
, p
);
9493 __task_rq_unlock(rq
);
9494 spin_unlock(&p
->pi_lock
);
9495 } while_each_thread(g
, p
);
9497 read_unlock_irqrestore(&tasklist_lock
, flags
);
9500 #endif /* CONFIG_MAGIC_SYSRQ */
9504 * These functions are only useful for the IA64 MCA handling.
9506 * They can only be called when the whole system has been
9507 * stopped - every CPU needs to be quiescent, and no scheduling
9508 * activity can take place. Using them for anything else would
9509 * be a serious bug, and as a result, they aren't even visible
9510 * under any other configuration.
9514 * curr_task - return the current task for a given cpu.
9515 * @cpu: the processor in question.
9517 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9519 struct task_struct
*curr_task(int cpu
)
9521 return cpu_curr(cpu
);
9525 * set_curr_task - set the current task for a given cpu.
9526 * @cpu: the processor in question.
9527 * @p: the task pointer to set.
9529 * Description: This function must only be used when non-maskable interrupts
9530 * are serviced on a separate stack. It allows the architecture to switch the
9531 * notion of the current task on a cpu in a non-blocking manner. This function
9532 * must be called with all CPU's synchronized, and interrupts disabled, the
9533 * and caller must save the original value of the current task (see
9534 * curr_task() above) and restore that value before reenabling interrupts and
9535 * re-starting the system.
9537 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9539 void set_curr_task(int cpu
, struct task_struct
*p
)
9546 #ifdef CONFIG_FAIR_GROUP_SCHED
9547 static void free_fair_sched_group(struct task_group
*tg
)
9551 for_each_possible_cpu(i
) {
9553 kfree(tg
->cfs_rq
[i
]);
9563 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9565 struct cfs_rq
*cfs_rq
;
9566 struct sched_entity
*se
;
9570 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9573 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
9577 tg
->shares
= NICE_0_LOAD
;
9579 for_each_possible_cpu(i
) {
9582 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
9583 GFP_KERNEL
, cpu_to_node(i
));
9587 se
= kzalloc_node(sizeof(struct sched_entity
),
9588 GFP_KERNEL
, cpu_to_node(i
));
9592 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
9601 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9603 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
9604 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
9607 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9609 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
9611 #else /* !CONFG_FAIR_GROUP_SCHED */
9612 static inline void free_fair_sched_group(struct task_group
*tg
)
9617 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9622 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
9626 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
9629 #endif /* CONFIG_FAIR_GROUP_SCHED */
9631 #ifdef CONFIG_RT_GROUP_SCHED
9632 static void free_rt_sched_group(struct task_group
*tg
)
9636 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
9638 for_each_possible_cpu(i
) {
9640 kfree(tg
->rt_rq
[i
]);
9642 kfree(tg
->rt_se
[i
]);
9650 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9652 struct rt_rq
*rt_rq
;
9653 struct sched_rt_entity
*rt_se
;
9657 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
9660 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
9664 init_rt_bandwidth(&tg
->rt_bandwidth
,
9665 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
9667 for_each_possible_cpu(i
) {
9670 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
9671 GFP_KERNEL
, cpu_to_node(i
));
9675 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
9676 GFP_KERNEL
, cpu_to_node(i
));
9680 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
9689 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9691 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
9692 &cpu_rq(cpu
)->leaf_rt_rq_list
);
9695 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9697 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
9699 #else /* !CONFIG_RT_GROUP_SCHED */
9700 static inline void free_rt_sched_group(struct task_group
*tg
)
9705 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
9710 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
9714 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
9717 #endif /* CONFIG_RT_GROUP_SCHED */
9719 #ifdef CONFIG_GROUP_SCHED
9720 static void free_sched_group(struct task_group
*tg
)
9722 free_fair_sched_group(tg
);
9723 free_rt_sched_group(tg
);
9727 /* allocate runqueue etc for a new task group */
9728 struct task_group
*sched_create_group(struct task_group
*parent
)
9730 struct task_group
*tg
;
9731 unsigned long flags
;
9734 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
9736 return ERR_PTR(-ENOMEM
);
9738 if (!alloc_fair_sched_group(tg
, parent
))
9741 if (!alloc_rt_sched_group(tg
, parent
))
9744 spin_lock_irqsave(&task_group_lock
, flags
);
9745 for_each_possible_cpu(i
) {
9746 register_fair_sched_group(tg
, i
);
9747 register_rt_sched_group(tg
, i
);
9749 list_add_rcu(&tg
->list
, &task_groups
);
9751 WARN_ON(!parent
); /* root should already exist */
9753 tg
->parent
= parent
;
9754 INIT_LIST_HEAD(&tg
->children
);
9755 list_add_rcu(&tg
->siblings
, &parent
->children
);
9756 spin_unlock_irqrestore(&task_group_lock
, flags
);
9761 free_sched_group(tg
);
9762 return ERR_PTR(-ENOMEM
);
9765 /* rcu callback to free various structures associated with a task group */
9766 static void free_sched_group_rcu(struct rcu_head
*rhp
)
9768 /* now it should be safe to free those cfs_rqs */
9769 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
9772 /* Destroy runqueue etc associated with a task group */
9773 void sched_destroy_group(struct task_group
*tg
)
9775 unsigned long flags
;
9778 spin_lock_irqsave(&task_group_lock
, flags
);
9779 for_each_possible_cpu(i
) {
9780 unregister_fair_sched_group(tg
, i
);
9781 unregister_rt_sched_group(tg
, i
);
9783 list_del_rcu(&tg
->list
);
9784 list_del_rcu(&tg
->siblings
);
9785 spin_unlock_irqrestore(&task_group_lock
, flags
);
9787 /* wait for possible concurrent references to cfs_rqs complete */
9788 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
9791 /* change task's runqueue when it moves between groups.
9792 * The caller of this function should have put the task in its new group
9793 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
9794 * reflect its new group.
9796 void sched_move_task(struct task_struct
*tsk
)
9799 unsigned long flags
;
9802 rq
= task_rq_lock(tsk
, &flags
);
9804 update_rq_clock(rq
);
9806 running
= task_current(rq
, tsk
);
9807 on_rq
= tsk
->se
.on_rq
;
9810 dequeue_task(rq
, tsk
, 0);
9811 if (unlikely(running
))
9812 tsk
->sched_class
->put_prev_task(rq
, tsk
);
9814 set_task_rq(tsk
, task_cpu(tsk
));
9816 #ifdef CONFIG_FAIR_GROUP_SCHED
9817 if (tsk
->sched_class
->moved_group
)
9818 tsk
->sched_class
->moved_group(tsk
);
9821 if (unlikely(running
))
9822 tsk
->sched_class
->set_curr_task(rq
);
9824 enqueue_task(rq
, tsk
, 0);
9826 task_rq_unlock(rq
, &flags
);
9828 #endif /* CONFIG_GROUP_SCHED */
9830 #ifdef CONFIG_FAIR_GROUP_SCHED
9831 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9833 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9838 dequeue_entity(cfs_rq
, se
, 0);
9840 se
->load
.weight
= shares
;
9841 se
->load
.inv_weight
= 0;
9844 enqueue_entity(cfs_rq
, se
, 0);
9847 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9849 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9850 struct rq
*rq
= cfs_rq
->rq
;
9851 unsigned long flags
;
9853 spin_lock_irqsave(&rq
->lock
, flags
);
9854 __set_se_shares(se
, shares
);
9855 spin_unlock_irqrestore(&rq
->lock
, flags
);
9858 static DEFINE_MUTEX(shares_mutex
);
9860 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
9863 unsigned long flags
;
9866 * We can't change the weight of the root cgroup.
9871 if (shares
< MIN_SHARES
)
9872 shares
= MIN_SHARES
;
9873 else if (shares
> MAX_SHARES
)
9874 shares
= MAX_SHARES
;
9876 mutex_lock(&shares_mutex
);
9877 if (tg
->shares
== shares
)
9880 spin_lock_irqsave(&task_group_lock
, flags
);
9881 for_each_possible_cpu(i
)
9882 unregister_fair_sched_group(tg
, i
);
9883 list_del_rcu(&tg
->siblings
);
9884 spin_unlock_irqrestore(&task_group_lock
, flags
);
9886 /* wait for any ongoing reference to this group to finish */
9887 synchronize_sched();
9890 * Now we are free to modify the group's share on each cpu
9891 * w/o tripping rebalance_share or load_balance_fair.
9893 tg
->shares
= shares
;
9894 for_each_possible_cpu(i
) {
9898 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
9899 set_se_shares(tg
->se
[i
], shares
);
9903 * Enable load balance activity on this group, by inserting it back on
9904 * each cpu's rq->leaf_cfs_rq_list.
9906 spin_lock_irqsave(&task_group_lock
, flags
);
9907 for_each_possible_cpu(i
)
9908 register_fair_sched_group(tg
, i
);
9909 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
9910 spin_unlock_irqrestore(&task_group_lock
, flags
);
9912 mutex_unlock(&shares_mutex
);
9916 unsigned long sched_group_shares(struct task_group
*tg
)
9922 #ifdef CONFIG_RT_GROUP_SCHED
9924 * Ensure that the real time constraints are schedulable.
9926 static DEFINE_MUTEX(rt_constraints_mutex
);
9928 static unsigned long to_ratio(u64 period
, u64 runtime
)
9930 if (runtime
== RUNTIME_INF
)
9933 return div64_u64(runtime
<< 20, period
);
9936 /* Must be called with tasklist_lock held */
9937 static inline int tg_has_rt_tasks(struct task_group
*tg
)
9939 struct task_struct
*g
, *p
;
9941 do_each_thread(g
, p
) {
9942 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
9944 } while_each_thread(g
, p
);
9949 struct rt_schedulable_data
{
9950 struct task_group
*tg
;
9955 static int tg_schedulable(struct task_group
*tg
, void *data
)
9957 struct rt_schedulable_data
*d
= data
;
9958 struct task_group
*child
;
9959 unsigned long total
, sum
= 0;
9960 u64 period
, runtime
;
9962 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9963 runtime
= tg
->rt_bandwidth
.rt_runtime
;
9966 period
= d
->rt_period
;
9967 runtime
= d
->rt_runtime
;
9970 #ifdef CONFIG_USER_SCHED
9971 if (tg
== &root_task_group
) {
9972 period
= global_rt_period();
9973 runtime
= global_rt_runtime();
9978 * Cannot have more runtime than the period.
9980 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9984 * Ensure we don't starve existing RT tasks.
9986 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
9989 total
= to_ratio(period
, runtime
);
9992 * Nobody can have more than the global setting allows.
9994 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
9998 * The sum of our children's runtime should not exceed our own.
10000 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
10001 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
10002 runtime
= child
->rt_bandwidth
.rt_runtime
;
10004 if (child
== d
->tg
) {
10005 period
= d
->rt_period
;
10006 runtime
= d
->rt_runtime
;
10009 sum
+= to_ratio(period
, runtime
);
10018 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
10020 struct rt_schedulable_data data
= {
10022 .rt_period
= period
,
10023 .rt_runtime
= runtime
,
10026 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
10029 static int tg_set_bandwidth(struct task_group
*tg
,
10030 u64 rt_period
, u64 rt_runtime
)
10034 mutex_lock(&rt_constraints_mutex
);
10035 read_lock(&tasklist_lock
);
10036 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
10040 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10041 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
10042 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
10044 for_each_possible_cpu(i
) {
10045 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
10047 spin_lock(&rt_rq
->rt_runtime_lock
);
10048 rt_rq
->rt_runtime
= rt_runtime
;
10049 spin_unlock(&rt_rq
->rt_runtime_lock
);
10051 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
10053 read_unlock(&tasklist_lock
);
10054 mutex_unlock(&rt_constraints_mutex
);
10059 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
10061 u64 rt_runtime
, rt_period
;
10063 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10064 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
10065 if (rt_runtime_us
< 0)
10066 rt_runtime
= RUNTIME_INF
;
10068 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10071 long sched_group_rt_runtime(struct task_group
*tg
)
10075 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
10078 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
10079 do_div(rt_runtime_us
, NSEC_PER_USEC
);
10080 return rt_runtime_us
;
10083 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
10085 u64 rt_runtime
, rt_period
;
10087 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
10088 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
10090 if (rt_period
== 0)
10093 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
10096 long sched_group_rt_period(struct task_group
*tg
)
10100 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
10101 do_div(rt_period_us
, NSEC_PER_USEC
);
10102 return rt_period_us
;
10105 static int sched_rt_global_constraints(void)
10107 u64 runtime
, period
;
10110 if (sysctl_sched_rt_period
<= 0)
10113 runtime
= global_rt_runtime();
10114 period
= global_rt_period();
10117 * Sanity check on the sysctl variables.
10119 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
10122 mutex_lock(&rt_constraints_mutex
);
10123 read_lock(&tasklist_lock
);
10124 ret
= __rt_schedulable(NULL
, 0, 0);
10125 read_unlock(&tasklist_lock
);
10126 mutex_unlock(&rt_constraints_mutex
);
10131 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
10133 /* Don't accept realtime tasks when there is no way for them to run */
10134 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
10140 #else /* !CONFIG_RT_GROUP_SCHED */
10141 static int sched_rt_global_constraints(void)
10143 unsigned long flags
;
10146 if (sysctl_sched_rt_period
<= 0)
10150 * There's always some RT tasks in the root group
10151 * -- migration, kstopmachine etc..
10153 if (sysctl_sched_rt_runtime
== 0)
10156 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10157 for_each_possible_cpu(i
) {
10158 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
10160 spin_lock(&rt_rq
->rt_runtime_lock
);
10161 rt_rq
->rt_runtime
= global_rt_runtime();
10162 spin_unlock(&rt_rq
->rt_runtime_lock
);
10164 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
10168 #endif /* CONFIG_RT_GROUP_SCHED */
10170 int sched_rt_handler(struct ctl_table
*table
, int write
,
10171 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
10175 int old_period
, old_runtime
;
10176 static DEFINE_MUTEX(mutex
);
10178 mutex_lock(&mutex
);
10179 old_period
= sysctl_sched_rt_period
;
10180 old_runtime
= sysctl_sched_rt_runtime
;
10182 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
10184 if (!ret
&& write
) {
10185 ret
= sched_rt_global_constraints();
10187 sysctl_sched_rt_period
= old_period
;
10188 sysctl_sched_rt_runtime
= old_runtime
;
10190 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
10191 def_rt_bandwidth
.rt_period
=
10192 ns_to_ktime(global_rt_period());
10195 mutex_unlock(&mutex
);
10200 #ifdef CONFIG_CGROUP_SCHED
10202 /* return corresponding task_group object of a cgroup */
10203 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
10205 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
10206 struct task_group
, css
);
10209 static struct cgroup_subsys_state
*
10210 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10212 struct task_group
*tg
, *parent
;
10214 if (!cgrp
->parent
) {
10215 /* This is early initialization for the top cgroup */
10216 return &init_task_group
.css
;
10219 parent
= cgroup_tg(cgrp
->parent
);
10220 tg
= sched_create_group(parent
);
10222 return ERR_PTR(-ENOMEM
);
10228 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10230 struct task_group
*tg
= cgroup_tg(cgrp
);
10232 sched_destroy_group(tg
);
10236 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10237 struct task_struct
*tsk
)
10239 #ifdef CONFIG_RT_GROUP_SCHED
10240 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
10243 /* We don't support RT-tasks being in separate groups */
10244 if (tsk
->sched_class
!= &fair_sched_class
)
10252 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
10253 struct cgroup
*old_cont
, struct task_struct
*tsk
)
10255 sched_move_task(tsk
);
10258 #ifdef CONFIG_FAIR_GROUP_SCHED
10259 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
10262 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
10265 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
10267 struct task_group
*tg
= cgroup_tg(cgrp
);
10269 return (u64
) tg
->shares
;
10271 #endif /* CONFIG_FAIR_GROUP_SCHED */
10273 #ifdef CONFIG_RT_GROUP_SCHED
10274 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
10277 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
10280 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10282 return sched_group_rt_runtime(cgroup_tg(cgrp
));
10285 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
10288 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
10291 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
10293 return sched_group_rt_period(cgroup_tg(cgrp
));
10295 #endif /* CONFIG_RT_GROUP_SCHED */
10297 static struct cftype cpu_files
[] = {
10298 #ifdef CONFIG_FAIR_GROUP_SCHED
10301 .read_u64
= cpu_shares_read_u64
,
10302 .write_u64
= cpu_shares_write_u64
,
10305 #ifdef CONFIG_RT_GROUP_SCHED
10307 .name
= "rt_runtime_us",
10308 .read_s64
= cpu_rt_runtime_read
,
10309 .write_s64
= cpu_rt_runtime_write
,
10312 .name
= "rt_period_us",
10313 .read_u64
= cpu_rt_period_read_uint
,
10314 .write_u64
= cpu_rt_period_write_uint
,
10319 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
10321 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
10324 struct cgroup_subsys cpu_cgroup_subsys
= {
10326 .create
= cpu_cgroup_create
,
10327 .destroy
= cpu_cgroup_destroy
,
10328 .can_attach
= cpu_cgroup_can_attach
,
10329 .attach
= cpu_cgroup_attach
,
10330 .populate
= cpu_cgroup_populate
,
10331 .subsys_id
= cpu_cgroup_subsys_id
,
10335 #endif /* CONFIG_CGROUP_SCHED */
10337 #ifdef CONFIG_CGROUP_CPUACCT
10340 * CPU accounting code for task groups.
10342 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
10343 * (balbir@in.ibm.com).
10346 /* track cpu usage of a group of tasks and its child groups */
10348 struct cgroup_subsys_state css
;
10349 /* cpuusage holds pointer to a u64-type object on every cpu */
10351 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
10352 struct cpuacct
*parent
;
10355 struct cgroup_subsys cpuacct_subsys
;
10357 /* return cpu accounting group corresponding to this container */
10358 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
10360 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
10361 struct cpuacct
, css
);
10364 /* return cpu accounting group to which this task belongs */
10365 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
10367 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
10368 struct cpuacct
, css
);
10371 /* create a new cpu accounting group */
10372 static struct cgroup_subsys_state
*cpuacct_create(
10373 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10375 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
10381 ca
->cpuusage
= alloc_percpu(u64
);
10385 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10386 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
10387 goto out_free_counters
;
10390 ca
->parent
= cgroup_ca(cgrp
->parent
);
10396 percpu_counter_destroy(&ca
->cpustat
[i
]);
10397 free_percpu(ca
->cpuusage
);
10401 return ERR_PTR(-ENOMEM
);
10404 /* destroy an existing cpu accounting group */
10406 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10408 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10411 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
10412 percpu_counter_destroy(&ca
->cpustat
[i
]);
10413 free_percpu(ca
->cpuusage
);
10417 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
10419 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10422 #ifndef CONFIG_64BIT
10424 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10426 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10428 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10436 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
10438 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10440 #ifndef CONFIG_64BIT
10442 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10444 spin_lock_irq(&cpu_rq(cpu
)->lock
);
10446 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
10452 /* return total cpu usage (in nanoseconds) of a group */
10453 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
10455 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10456 u64 totalcpuusage
= 0;
10459 for_each_present_cpu(i
)
10460 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
10462 return totalcpuusage
;
10465 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
10468 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10477 for_each_present_cpu(i
)
10478 cpuacct_cpuusage_write(ca
, i
, 0);
10484 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
10485 struct seq_file
*m
)
10487 struct cpuacct
*ca
= cgroup_ca(cgroup
);
10491 for_each_present_cpu(i
) {
10492 percpu
= cpuacct_cpuusage_read(ca
, i
);
10493 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
10495 seq_printf(m
, "\n");
10499 static const char *cpuacct_stat_desc
[] = {
10500 [CPUACCT_STAT_USER
] = "user",
10501 [CPUACCT_STAT_SYSTEM
] = "system",
10504 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
10505 struct cgroup_map_cb
*cb
)
10507 struct cpuacct
*ca
= cgroup_ca(cgrp
);
10510 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
10511 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
10512 val
= cputime64_to_clock_t(val
);
10513 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
10518 static struct cftype files
[] = {
10521 .read_u64
= cpuusage_read
,
10522 .write_u64
= cpuusage_write
,
10525 .name
= "usage_percpu",
10526 .read_seq_string
= cpuacct_percpu_seq_read
,
10530 .read_map
= cpuacct_stats_show
,
10534 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
10536 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
10540 * charge this task's execution time to its accounting group.
10542 * called with rq->lock held.
10544 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
10546 struct cpuacct
*ca
;
10549 if (unlikely(!cpuacct_subsys
.active
))
10552 cpu
= task_cpu(tsk
);
10558 for (; ca
; ca
= ca
->parent
) {
10559 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
10560 *cpuusage
+= cputime
;
10567 * Charge the system/user time to the task's accounting group.
10569 static void cpuacct_update_stats(struct task_struct
*tsk
,
10570 enum cpuacct_stat_index idx
, cputime_t val
)
10572 struct cpuacct
*ca
;
10574 if (unlikely(!cpuacct_subsys
.active
))
10581 percpu_counter_add(&ca
->cpustat
[idx
], val
);
10587 struct cgroup_subsys cpuacct_subsys
= {
10589 .create
= cpuacct_create
,
10590 .destroy
= cpuacct_destroy
,
10591 .populate
= cpuacct_populate
,
10592 .subsys_id
= cpuacct_subsys_id
,
10594 #endif /* CONFIG_CGROUP_CPUACCT */