4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/kthread.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/reciprocal_div.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/bootmem.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
75 #include <trace/sched.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
83 * Convert user-nice values [ -20 ... 0 ... 19 ]
84 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
87 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
88 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
89 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
92 * 'User priority' is the nice value converted to something we
93 * can work with better when scaling various scheduler parameters,
94 * it's a [ 0 ... 39 ] range.
96 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
97 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
98 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
101 * Helpers for converting nanosecond timing to jiffy resolution
103 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
105 #define NICE_0_LOAD SCHED_LOAD_SCALE
106 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
109 * These are the 'tuning knobs' of the scheduler:
111 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
112 * Timeslices get refilled after they expire.
114 #define DEF_TIMESLICE (100 * HZ / 1000)
117 * single value that denotes runtime == period, ie unlimited time.
119 #define RUNTIME_INF ((u64)~0ULL)
121 DEFINE_TRACE(sched_wait_task);
122 DEFINE_TRACE(sched_wakeup);
123 DEFINE_TRACE(sched_wakeup_new);
124 DEFINE_TRACE(sched_switch);
125 DEFINE_TRACE(sched_migrate_task);
129 static void double_rq_lock(struct rq *rq1, struct rq *rq2);
132 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
133 * Since cpu_power is a 'constant', we can use a reciprocal divide.
135 static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
137 return reciprocal_divide(load, sg->reciprocal_cpu_power);
141 * Each time a sched group cpu_power is changed,
142 * we must compute its reciprocal value
144 static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
146 sg->__cpu_power += val;
147 sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
151 static inline int rt_policy(int policy)
153 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
158 static inline int task_has_rt_policy(struct task_struct *p)
160 return rt_policy(p->policy);
164 * This is the priority-queue data structure of the RT scheduling class:
166 struct rt_prio_array {
167 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
168 struct list_head queue[MAX_RT_PRIO];
171 struct rt_bandwidth {
172 /* nests inside the rq lock: */
173 spinlock_t rt_runtime_lock;
176 struct hrtimer rt_period_timer;
179 static struct rt_bandwidth def_rt_bandwidth;
181 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
183 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
185 struct rt_bandwidth *rt_b =
186 container_of(timer, struct rt_bandwidth, rt_period_timer);
192 now = hrtimer_cb_get_time(timer);
193 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
198 idle = do_sched_rt_period_timer(rt_b, overrun);
201 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
205 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
207 rt_b->rt_period = ns_to_ktime(period);
208 rt_b->rt_runtime = runtime;
210 spin_lock_init(&rt_b->rt_runtime_lock);
212 hrtimer_init(&rt_b->rt_period_timer,
213 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
214 rt_b->rt_period_timer.function = sched_rt_period_timer;
217 static inline int rt_bandwidth_enabled(void)
219 return sysctl_sched_rt_runtime >= 0;
222 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
226 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
229 if (hrtimer_active(&rt_b->rt_period_timer))
232 spin_lock(&rt_b->rt_runtime_lock);
234 if (hrtimer_active(&rt_b->rt_period_timer))
237 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
238 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
239 hrtimer_start_expires(&rt_b->rt_period_timer,
242 spin_unlock(&rt_b->rt_runtime_lock);
245 #ifdef CONFIG_RT_GROUP_SCHED
246 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
248 hrtimer_cancel(&rt_b->rt_period_timer);
253 * sched_domains_mutex serializes calls to arch_init_sched_domains,
254 * detach_destroy_domains and partition_sched_domains.
256 static DEFINE_MUTEX(sched_domains_mutex);
258 #ifdef CONFIG_GROUP_SCHED
260 #include <linux/cgroup.h>
264 static LIST_HEAD(task_groups);
266 /* task group related information */
268 #ifdef CONFIG_CGROUP_SCHED
269 struct cgroup_subsys_state css;
272 #ifdef CONFIG_USER_SCHED
276 #ifdef CONFIG_FAIR_GROUP_SCHED
277 /* schedulable entities of this group on each cpu */
278 struct sched_entity **se;
279 /* runqueue "owned" by this group on each cpu */
280 struct cfs_rq **cfs_rq;
281 unsigned long shares;
284 #ifdef CONFIG_RT_GROUP_SCHED
285 struct sched_rt_entity **rt_se;
286 struct rt_rq **rt_rq;
288 struct rt_bandwidth rt_bandwidth;
292 struct list_head list;
294 struct task_group *parent;
295 struct list_head siblings;
296 struct list_head children;
299 #ifdef CONFIG_USER_SCHED
301 /* Helper function to pass uid information to create_sched_user() */
302 void set_tg_uid(struct user_struct *user)
304 user->tg->uid = user->uid;
309 * Every UID task group (including init_task_group aka UID-0) will
310 * be a child to this group.
312 struct task_group root_task_group;
314 #ifdef CONFIG_FAIR_GROUP_SCHED
315 /* Default task group's sched entity on each cpu */
316 static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
317 /* Default task group's cfs_rq on each cpu */
318 static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
319 #endif /* CONFIG_FAIR_GROUP_SCHED */
321 #ifdef CONFIG_RT_GROUP_SCHED
322 static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
323 static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
324 #endif /* CONFIG_RT_GROUP_SCHED */
325 #else /* !CONFIG_USER_SCHED */
326 #define root_task_group init_task_group
327 #endif /* CONFIG_USER_SCHED */
329 /* task_group_lock serializes add/remove of task groups and also changes to
330 * a task group's cpu shares.
332 static DEFINE_SPINLOCK(task_group_lock);
335 static int root_task_group_empty(void)
337 return list_empty(&root_task_group.children);
341 #ifdef CONFIG_FAIR_GROUP_SCHED
342 #ifdef CONFIG_USER_SCHED
343 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
344 #else /* !CONFIG_USER_SCHED */
345 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
346 #endif /* CONFIG_USER_SCHED */
349 * A weight of 0 or 1 can cause arithmetics problems.
350 * A weight of a cfs_rq is the sum of weights of which entities
351 * are queued on this cfs_rq, so a weight of a entity should not be
352 * too large, so as the shares value of a task group.
353 * (The default weight is 1024 - so there's no practical
354 * limitation from this.)
357 #define MAX_SHARES (1UL << 18)
359 static int init_task_group_load = INIT_TASK_GROUP_LOAD;
362 /* Default task group.
363 * Every task in system belong to this group at bootup.
365 struct task_group init_task_group;
367 /* return group to which a task belongs */
368 static inline struct task_group *task_group(struct task_struct *p)
370 struct task_group *tg;
372 #ifdef CONFIG_USER_SCHED
374 tg = __task_cred(p)->user->tg;
376 #elif defined(CONFIG_CGROUP_SCHED)
377 tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
378 struct task_group, css);
380 tg = &init_task_group;
385 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
386 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
388 #ifdef CONFIG_FAIR_GROUP_SCHED
389 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
390 p->se.parent = task_group(p)->se[cpu];
393 #ifdef CONFIG_RT_GROUP_SCHED
394 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
395 p->rt.parent = task_group(p)->rt_se[cpu];
402 static int root_task_group_empty(void)
408 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
409 static inline struct task_group *task_group(struct task_struct *p)
414 #endif /* CONFIG_GROUP_SCHED */
416 /* CFS-related fields in a runqueue */
418 struct load_weight load;
419 unsigned long nr_running;
424 struct rb_root tasks_timeline;
425 struct rb_node *rb_leftmost;
427 struct list_head tasks;
428 struct list_head *balance_iterator;
431 * 'curr' points to currently running entity on this cfs_rq.
432 * It is set to NULL otherwise (i.e when none are currently running).
434 struct sched_entity *curr, *next, *last;
436 unsigned int nr_spread_over;
438 #ifdef CONFIG_FAIR_GROUP_SCHED
439 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
442 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
443 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
444 * (like users, containers etc.)
446 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
447 * list is used during load balance.
449 struct list_head leaf_cfs_rq_list;
450 struct task_group *tg; /* group that "owns" this runqueue */
454 * the part of load.weight contributed by tasks
456 unsigned long task_weight;
459 * h_load = weight * f(tg)
461 * Where f(tg) is the recursive weight fraction assigned to
464 unsigned long h_load;
467 * this cpu's part of tg->shares
469 unsigned long shares;
472 * load.weight at the time we set shares
474 unsigned long rq_weight;
479 /* Real-Time classes' related field in a runqueue: */
481 struct rt_prio_array active;
482 unsigned long rt_nr_running;
483 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
485 int curr; /* highest queued rt task prio */
487 int next; /* next highest */
492 unsigned long rt_nr_migratory;
494 struct plist_head pushable_tasks;
499 /* Nests inside the rq lock: */
500 spinlock_t rt_runtime_lock;
502 #ifdef CONFIG_RT_GROUP_SCHED
503 unsigned long rt_nr_boosted;
506 struct list_head leaf_rt_rq_list;
507 struct task_group *tg;
508 struct sched_rt_entity *rt_se;
515 * We add the notion of a root-domain which will be used to define per-domain
516 * variables. Each exclusive cpuset essentially defines an island domain by
517 * fully partitioning the member cpus from any other cpuset. Whenever a new
518 * exclusive cpuset is created, we also create and attach a new root-domain
525 cpumask_var_t online;
528 * The "RT overload" flag: it gets set if a CPU has more than
529 * one runnable RT task.
531 cpumask_var_t rto_mask;
534 struct cpupri cpupri;
536 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
538 * Preferred wake up cpu nominated by sched_mc balance that will be
539 * used when most cpus are idle in the system indicating overall very
540 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
542 unsigned int sched_mc_preferred_wakeup_cpu;
547 * By default the system creates a single root-domain with all cpus as
548 * members (mimicking the global state we have today).
550 static struct root_domain def_root_domain;
555 * This is the main, per-CPU runqueue data structure.
557 * Locking rule: those places that want to lock multiple runqueues
558 * (such as the load balancing or the thread migration code), lock
559 * acquire operations must be ordered by ascending &runqueue.
566 * nr_running and cpu_load should be in the same cacheline because
567 * remote CPUs use both these fields when doing load calculation.
569 unsigned long nr_running;
570 #define CPU_LOAD_IDX_MAX 5
571 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
573 unsigned long last_tick_seen;
574 unsigned char in_nohz_recently;
576 /* capture load from *all* tasks on this cpu: */
577 struct load_weight load;
578 unsigned long nr_load_updates;
584 #ifdef CONFIG_FAIR_GROUP_SCHED
585 /* list of leaf cfs_rq on this cpu: */
586 struct list_head leaf_cfs_rq_list;
588 #ifdef CONFIG_RT_GROUP_SCHED
589 struct list_head leaf_rt_rq_list;
593 * This is part of a global counter where only the total sum
594 * over all CPUs matters. A task can increase this counter on
595 * one CPU and if it got migrated afterwards it may decrease
596 * it on another CPU. Always updated under the runqueue lock:
598 unsigned long nr_uninterruptible;
600 struct task_struct *curr, *idle;
601 unsigned long next_balance;
602 struct mm_struct *prev_mm;
609 struct root_domain *rd;
610 struct sched_domain *sd;
612 unsigned char idle_at_tick;
613 /* For active balancing */
616 /* cpu of this runqueue: */
620 unsigned long avg_load_per_task;
622 struct task_struct *migration_thread;
623 struct list_head migration_queue;
626 #ifdef CONFIG_SCHED_HRTICK
628 int hrtick_csd_pending;
629 struct call_single_data hrtick_csd;
631 struct hrtimer hrtick_timer;
634 #ifdef CONFIG_SCHEDSTATS
636 struct sched_info rq_sched_info;
637 unsigned long long rq_cpu_time;
638 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
640 /* sys_sched_yield() stats */
641 unsigned int yld_count;
643 /* schedule() stats */
644 unsigned int sched_switch;
645 unsigned int sched_count;
646 unsigned int sched_goidle;
648 /* try_to_wake_up() stats */
649 unsigned int ttwu_count;
650 unsigned int ttwu_local;
653 unsigned int bkl_count;
657 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
659 static inline void check_preempt_curr(struct rq *rq, struct task_struct *p, int sync)
661 rq->curr->sched_class->check_preempt_curr(rq, p, sync);
664 static inline int cpu_of(struct rq *rq)
674 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
675 * See detach_destroy_domains: synchronize_sched for details.
677 * The domain tree of any CPU may only be accessed from within
678 * preempt-disabled sections.
680 #define for_each_domain(cpu, __sd) \
681 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
683 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
684 #define this_rq() (&__get_cpu_var(runqueues))
685 #define task_rq(p) cpu_rq(task_cpu(p))
686 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
688 static inline void update_rq_clock(struct rq *rq)
690 rq->clock = sched_clock_cpu(cpu_of(rq));
694 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
696 #ifdef CONFIG_SCHED_DEBUG
697 # define const_debug __read_mostly
699 # define const_debug static const
705 * Returns true if the current cpu runqueue is locked.
706 * This interface allows printk to be called with the runqueue lock
707 * held and know whether or not it is OK to wake up the klogd.
709 int runqueue_is_locked(void)
712 struct rq *rq = cpu_rq(cpu);
715 ret = spin_is_locked(&rq->lock);
721 * Debugging: various feature bits
724 #define SCHED_FEAT(name, enabled) \
725 __SCHED_FEAT_##name ,
728 #include "sched_features.h"
733 #define SCHED_FEAT(name, enabled) \
734 (1UL << __SCHED_FEAT_##name) * enabled |
736 const_debug unsigned int sysctl_sched_features =
737 #include "sched_features.h"
742 #ifdef CONFIG_SCHED_DEBUG
743 #define SCHED_FEAT(name, enabled) \
746 static __read_mostly char *sched_feat_names[] = {
747 #include "sched_features.h"
753 static int sched_feat_show(struct seq_file *m, void *v)
757 for (i = 0; sched_feat_names[i]; i++) {
758 if (!(sysctl_sched_features & (1UL << i)))
760 seq_printf(m, "%s ", sched_feat_names[i]);
768 sched_feat_write(struct file *filp, const char __user *ubuf,
769 size_t cnt, loff_t *ppos)
779 if (copy_from_user(&buf, ubuf, cnt))
784 if (strncmp(buf, "NO_", 3) == 0) {
789 for (i = 0; sched_feat_names[i]; i++) {
790 int len = strlen(sched_feat_names[i]);
792 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
794 sysctl_sched_features &= ~(1UL << i);
796 sysctl_sched_features |= (1UL << i);
801 if (!sched_feat_names[i])
809 static int sched_feat_open(struct inode *inode, struct file *filp)
811 return single_open(filp, sched_feat_show, NULL);
814 static struct file_operations sched_feat_fops = {
815 .open = sched_feat_open,
816 .write = sched_feat_write,
819 .release = single_release,
822 static __init int sched_init_debug(void)
824 debugfs_create_file("sched_features", 0644, NULL, NULL,
829 late_initcall(sched_init_debug);
833 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
836 * Number of tasks to iterate in a single balance run.
837 * Limited because this is done with IRQs disabled.
839 const_debug unsigned int sysctl_sched_nr_migrate = 32;
842 * ratelimit for updating the group shares.
845 unsigned int sysctl_sched_shares_ratelimit = 250000;
848 * Inject some fuzzyness into changing the per-cpu group shares
849 * this avoids remote rq-locks at the expense of fairness.
852 unsigned int sysctl_sched_shares_thresh = 4;
855 * period over which we measure -rt task cpu usage in us.
858 unsigned int sysctl_sched_rt_period = 1000000;
860 static __read_mostly int scheduler_running;
863 * part of the period that we allow rt tasks to run in us.
866 int sysctl_sched_rt_runtime = 950000;
868 static inline u64 global_rt_period(void)
870 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
873 static inline u64 global_rt_runtime(void)
875 if (sysctl_sched_rt_runtime < 0)
878 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
881 #ifndef prepare_arch_switch
882 # define prepare_arch_switch(next) do { } while (0)
884 #ifndef finish_arch_switch
885 # define finish_arch_switch(prev) do { } while (0)
888 static inline int task_current(struct rq *rq, struct task_struct *p)
890 return rq->curr == p;
893 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
894 static inline int task_running(struct rq *rq, struct task_struct *p)
896 return task_current(rq, p);
899 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
903 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
905 #ifdef CONFIG_DEBUG_SPINLOCK
906 /* this is a valid case when another task releases the spinlock */
907 rq->lock.owner = current;
910 * If we are tracking spinlock dependencies then we have to
911 * fix up the runqueue lock - which gets 'carried over' from
914 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
916 spin_unlock_irq(&rq->lock);
919 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
920 static inline int task_running(struct rq *rq, struct task_struct *p)
925 return task_current(rq, p);
929 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
933 * We can optimise this out completely for !SMP, because the
934 * SMP rebalancing from interrupt is the only thing that cares
939 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
940 spin_unlock_irq(&rq->lock);
942 spin_unlock(&rq->lock);
946 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
950 * After ->oncpu is cleared, the task can be moved to a different CPU.
951 * We must ensure this doesn't happen until the switch is completely
957 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
961 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
964 * __task_rq_lock - lock the runqueue a given task resides on.
965 * Must be called interrupts disabled.
967 static inline struct rq *__task_rq_lock(struct task_struct *p)
971 struct rq *rq = task_rq(p);
972 spin_lock(&rq->lock);
973 if (likely(rq == task_rq(p)))
975 spin_unlock(&rq->lock);
980 * task_rq_lock - lock the runqueue a given task resides on and disable
981 * interrupts. Note the ordering: we can safely lookup the task_rq without
982 * explicitly disabling preemption.
984 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
990 local_irq_save(*flags);
992 spin_lock(&rq->lock);
993 if (likely(rq == task_rq(p)))
995 spin_unlock_irqrestore(&rq->lock, *flags);
999 void task_rq_unlock_wait(struct task_struct *p)
1001 struct rq *rq = task_rq(p);
1003 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1004 spin_unlock_wait(&rq->lock);
1007 static void __task_rq_unlock(struct rq *rq)
1008 __releases(rq->lock)
1010 spin_unlock(&rq->lock);
1013 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
1014 __releases(rq->lock)
1016 spin_unlock_irqrestore(&rq->lock, *flags);
1020 * this_rq_lock - lock this runqueue and disable interrupts.
1022 static struct rq *this_rq_lock(void)
1023 __acquires(rq->lock)
1027 local_irq_disable();
1029 spin_lock(&rq->lock);
1034 #ifdef CONFIG_SCHED_HRTICK
1036 * Use HR-timers to deliver accurate preemption points.
1038 * Its all a bit involved since we cannot program an hrt while holding the
1039 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1042 * When we get rescheduled we reprogram the hrtick_timer outside of the
1048 * - enabled by features
1049 * - hrtimer is actually high res
1051 static inline int hrtick_enabled(struct rq *rq)
1053 if (!sched_feat(HRTICK))
1055 if (!cpu_active(cpu_of(rq)))
1057 return hrtimer_is_hres_active(&rq->hrtick_timer);
1060 static void hrtick_clear(struct rq *rq)
1062 if (hrtimer_active(&rq->hrtick_timer))
1063 hrtimer_cancel(&rq->hrtick_timer);
1067 * High-resolution timer tick.
1068 * Runs from hardirq context with interrupts disabled.
1070 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1072 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1074 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1076 spin_lock(&rq->lock);
1077 update_rq_clock(rq);
1078 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1079 spin_unlock(&rq->lock);
1081 return HRTIMER_NORESTART;
1086 * called from hardirq (IPI) context
1088 static void __hrtick_start(void *arg)
1090 struct rq *rq = arg;
1092 spin_lock(&rq->lock);
1093 hrtimer_restart(&rq->hrtick_timer);
1094 rq->hrtick_csd_pending = 0;
1095 spin_unlock(&rq->lock);
1099 * Called to set the hrtick timer state.
1101 * called with rq->lock held and irqs disabled
1103 static void hrtick_start(struct rq *rq, u64 delay)
1105 struct hrtimer *timer = &rq->hrtick_timer;
1106 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
1108 hrtimer_set_expires(timer, time);
1110 if (rq == this_rq()) {
1111 hrtimer_restart(timer);
1112 } else if (!rq->hrtick_csd_pending) {
1113 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd);
1114 rq->hrtick_csd_pending = 1;
1119 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1121 int cpu = (int)(long)hcpu;
1124 case CPU_UP_CANCELED:
1125 case CPU_UP_CANCELED_FROZEN:
1126 case CPU_DOWN_PREPARE:
1127 case CPU_DOWN_PREPARE_FROZEN:
1129 case CPU_DEAD_FROZEN:
1130 hrtick_clear(cpu_rq(cpu));
1137 static __init void init_hrtick(void)
1139 hotcpu_notifier(hotplug_hrtick, 0);
1143 * Called to set the hrtick timer state.
1145 * called with rq->lock held and irqs disabled
1147 static void hrtick_start(struct rq *rq, u64 delay)
1149 hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), HRTIMER_MODE_REL);
1152 static inline void init_hrtick(void)
1155 #endif /* CONFIG_SMP */
1157 static void init_rq_hrtick(struct rq *rq)
1160 rq->hrtick_csd_pending = 0;
1162 rq->hrtick_csd.flags = 0;
1163 rq->hrtick_csd.func = __hrtick_start;
1164 rq->hrtick_csd.info = rq;
1167 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1168 rq->hrtick_timer.function = hrtick;
1170 #else /* CONFIG_SCHED_HRTICK */
1171 static inline void hrtick_clear(struct rq *rq)
1175 static inline void init_rq_hrtick(struct rq *rq)
1179 static inline void init_hrtick(void)
1182 #endif /* CONFIG_SCHED_HRTICK */
1185 * resched_task - mark a task 'to be rescheduled now'.
1187 * On UP this means the setting of the need_resched flag, on SMP it
1188 * might also involve a cross-CPU call to trigger the scheduler on
1193 #ifndef tsk_is_polling
1194 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1197 static void resched_task(struct task_struct *p)
1201 assert_spin_locked(&task_rq(p)->lock);
1203 if (test_tsk_need_resched(p))
1206 set_tsk_need_resched(p);
1209 if (cpu == smp_processor_id())
1212 /* NEED_RESCHED must be visible before we test polling */
1214 if (!tsk_is_polling(p))
1215 smp_send_reschedule(cpu);
1218 static void resched_cpu(int cpu)
1220 struct rq *rq = cpu_rq(cpu);
1221 unsigned long flags;
1223 if (!spin_trylock_irqsave(&rq->lock, flags))
1225 resched_task(cpu_curr(cpu));
1226 spin_unlock_irqrestore(&rq->lock, flags);
1231 * When add_timer_on() enqueues a timer into the timer wheel of an
1232 * idle CPU then this timer might expire before the next timer event
1233 * which is scheduled to wake up that CPU. In case of a completely
1234 * idle system the next event might even be infinite time into the
1235 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1236 * leaves the inner idle loop so the newly added timer is taken into
1237 * account when the CPU goes back to idle and evaluates the timer
1238 * wheel for the next timer event.
1240 void wake_up_idle_cpu(int cpu)
1242 struct rq *rq = cpu_rq(cpu);
1244 if (cpu == smp_processor_id())
1248 * This is safe, as this function is called with the timer
1249 * wheel base lock of (cpu) held. When the CPU is on the way
1250 * to idle and has not yet set rq->curr to idle then it will
1251 * be serialized on the timer wheel base lock and take the new
1252 * timer into account automatically.
1254 if (rq->curr != rq->idle)
1258 * We can set TIF_RESCHED on the idle task of the other CPU
1259 * lockless. The worst case is that the other CPU runs the
1260 * idle task through an additional NOOP schedule()
1262 set_tsk_need_resched(rq->idle);
1264 /* NEED_RESCHED must be visible before we test polling */
1266 if (!tsk_is_polling(rq->idle))
1267 smp_send_reschedule(cpu);
1269 #endif /* CONFIG_NO_HZ */
1271 #else /* !CONFIG_SMP */
1272 static void resched_task(struct task_struct *p)
1274 assert_spin_locked(&task_rq(p)->lock);
1275 set_tsk_need_resched(p);
1277 #endif /* CONFIG_SMP */
1279 #if BITS_PER_LONG == 32
1280 # define WMULT_CONST (~0UL)
1282 # define WMULT_CONST (1UL << 32)
1285 #define WMULT_SHIFT 32
1288 * Shift right and round:
1290 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1293 * delta *= weight / lw
1295 static unsigned long
1296 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1297 struct load_weight *lw)
1301 if (!lw->inv_weight) {
1302 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1305 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1309 tmp = (u64)delta_exec * weight;
1311 * Check whether we'd overflow the 64-bit multiplication:
1313 if (unlikely(tmp > WMULT_CONST))
1314 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1317 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1319 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1322 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1328 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1335 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1336 * of tasks with abnormal "nice" values across CPUs the contribution that
1337 * each task makes to its run queue's load is weighted according to its
1338 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1339 * scaled version of the new time slice allocation that they receive on time
1343 #define WEIGHT_IDLEPRIO 3
1344 #define WMULT_IDLEPRIO 1431655765
1347 * Nice levels are multiplicative, with a gentle 10% change for every
1348 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1349 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1350 * that remained on nice 0.
1352 * The "10% effect" is relative and cumulative: from _any_ nice level,
1353 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1354 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1355 * If a task goes up by ~10% and another task goes down by ~10% then
1356 * the relative distance between them is ~25%.)
1358 static const int prio_to_weight[40] = {
1359 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1360 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1361 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1362 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1363 /* 0 */ 1024, 820, 655, 526, 423,
1364 /* 5 */ 335, 272, 215, 172, 137,
1365 /* 10 */ 110, 87, 70, 56, 45,
1366 /* 15 */ 36, 29, 23, 18, 15,
1370 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1372 * In cases where the weight does not change often, we can use the
1373 * precalculated inverse to speed up arithmetics by turning divisions
1374 * into multiplications:
1376 static const u32 prio_to_wmult[40] = {
1377 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1378 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1379 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1380 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1381 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1382 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1383 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1384 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1387 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
1390 * runqueue iterator, to support SMP load-balancing between different
1391 * scheduling classes, without having to expose their internal data
1392 * structures to the load-balancing proper:
1394 struct rq_iterator {
1396 struct task_struct *(*start)(void *);
1397 struct task_struct *(*next)(void *);
1401 static unsigned long
1402 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
1403 unsigned long max_load_move, struct sched_domain *sd,
1404 enum cpu_idle_type idle, int *all_pinned,
1405 int *this_best_prio, struct rq_iterator *iterator);
1408 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
1409 struct sched_domain *sd, enum cpu_idle_type idle,
1410 struct rq_iterator *iterator);
1413 #ifdef CONFIG_CGROUP_CPUACCT
1414 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1416 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1419 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1421 update_load_add(&rq->load, load);
1424 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1426 update_load_sub(&rq->load, load);
1429 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1430 typedef int (*tg_visitor)(struct task_group *, void *);
1433 * Iterate the full tree, calling @down when first entering a node and @up when
1434 * leaving it for the final time.
1436 static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
1438 struct task_group *parent, *child;
1442 parent = &root_task_group;
1444 ret = (*down)(parent, data);
1447 list_for_each_entry_rcu(child, &parent->children, siblings) {
1454 ret = (*up)(parent, data);
1459 parent = parent->parent;
1468 static int tg_nop(struct task_group *tg, void *data)
1475 static unsigned long source_load(int cpu, int type);
1476 static unsigned long target_load(int cpu, int type);
1477 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1479 static unsigned long cpu_avg_load_per_task(int cpu)
1481 struct rq *rq = cpu_rq(cpu);
1482 unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
1485 rq->avg_load_per_task = rq->load.weight / nr_running;
1487 rq->avg_load_per_task = 0;
1489 return rq->avg_load_per_task;
1492 #ifdef CONFIG_FAIR_GROUP_SCHED
1494 static void __set_se_shares(struct sched_entity *se, unsigned long shares);
1497 * Calculate and set the cpu's group shares.
1500 update_group_shares_cpu(struct task_group *tg, int cpu,
1501 unsigned long sd_shares, unsigned long sd_rq_weight)
1503 unsigned long shares;
1504 unsigned long rq_weight;
1509 rq_weight = tg->cfs_rq[cpu]->rq_weight;
1512 * \Sum shares * rq_weight
1513 * shares = -----------------------
1517 shares = (sd_shares * rq_weight) / sd_rq_weight;
1518 shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
1520 if (abs(shares - tg->se[cpu]->load.weight) >
1521 sysctl_sched_shares_thresh) {
1522 struct rq *rq = cpu_rq(cpu);
1523 unsigned long flags;
1525 spin_lock_irqsave(&rq->lock, flags);
1526 tg->cfs_rq[cpu]->shares = shares;
1528 __set_se_shares(tg->se[cpu], shares);
1529 spin_unlock_irqrestore(&rq->lock, flags);
1534 * Re-compute the task group their per cpu shares over the given domain.
1535 * This needs to be done in a bottom-up fashion because the rq weight of a
1536 * parent group depends on the shares of its child groups.
1538 static int tg_shares_up(struct task_group *tg, void *data)
1540 unsigned long weight, rq_weight = 0;
1541 unsigned long shares = 0;
1542 struct sched_domain *sd = data;
1545 for_each_cpu(i, sched_domain_span(sd)) {
1547 * If there are currently no tasks on the cpu pretend there
1548 * is one of average load so that when a new task gets to
1549 * run here it will not get delayed by group starvation.
1551 weight = tg->cfs_rq[i]->load.weight;
1553 weight = NICE_0_LOAD;
1555 tg->cfs_rq[i]->rq_weight = weight;
1556 rq_weight += weight;
1557 shares += tg->cfs_rq[i]->shares;
1560 if ((!shares && rq_weight) || shares > tg->shares)
1561 shares = tg->shares;
1563 if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
1564 shares = tg->shares;
1566 for_each_cpu(i, sched_domain_span(sd))
1567 update_group_shares_cpu(tg, i, shares, rq_weight);
1573 * Compute the cpu's hierarchical load factor for each task group.
1574 * This needs to be done in a top-down fashion because the load of a child
1575 * group is a fraction of its parents load.
1577 static int tg_load_down(struct task_group *tg, void *data)
1580 long cpu = (long)data;
1583 load = cpu_rq(cpu)->load.weight;
1585 load = tg->parent->cfs_rq[cpu]->h_load;
1586 load *= tg->cfs_rq[cpu]->shares;
1587 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
1590 tg->cfs_rq[cpu]->h_load = load;
1595 static void update_shares(struct sched_domain *sd)
1597 u64 now = cpu_clock(raw_smp_processor_id());
1598 s64 elapsed = now - sd->last_update;
1600 if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
1601 sd->last_update = now;
1602 walk_tg_tree(tg_nop, tg_shares_up, sd);
1606 static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1608 spin_unlock(&rq->lock);
1610 spin_lock(&rq->lock);
1613 static void update_h_load(long cpu)
1615 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
1620 static inline void update_shares(struct sched_domain *sd)
1624 static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1630 #ifdef CONFIG_PREEMPT
1633 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1634 * way at the expense of forcing extra atomic operations in all
1635 * invocations. This assures that the double_lock is acquired using the
1636 * same underlying policy as the spinlock_t on this architecture, which
1637 * reduces latency compared to the unfair variant below. However, it
1638 * also adds more overhead and therefore may reduce throughput.
1640 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1641 __releases(this_rq->lock)
1642 __acquires(busiest->lock)
1643 __acquires(this_rq->lock)
1645 spin_unlock(&this_rq->lock);
1646 double_rq_lock(this_rq, busiest);
1653 * Unfair double_lock_balance: Optimizes throughput at the expense of
1654 * latency by eliminating extra atomic operations when the locks are
1655 * already in proper order on entry. This favors lower cpu-ids and will
1656 * grant the double lock to lower cpus over higher ids under contention,
1657 * regardless of entry order into the function.
1659 static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1660 __releases(this_rq->lock)
1661 __acquires(busiest->lock)
1662 __acquires(this_rq->lock)
1666 if (unlikely(!spin_trylock(&busiest->lock))) {
1667 if (busiest < this_rq) {
1668 spin_unlock(&this_rq->lock);
1669 spin_lock(&busiest->lock);
1670 spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING);
1673 spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING);
1678 #endif /* CONFIG_PREEMPT */
1681 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1683 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1685 if (unlikely(!irqs_disabled())) {
1686 /* printk() doesn't work good under rq->lock */
1687 spin_unlock(&this_rq->lock);
1691 return _double_lock_balance(this_rq, busiest);
1694 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1695 __releases(busiest->lock)
1697 spin_unlock(&busiest->lock);
1698 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1702 #ifdef CONFIG_FAIR_GROUP_SCHED
1703 static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
1706 cfs_rq->shares = shares;
1711 #include "sched_stats.h"
1712 #include "sched_idletask.c"
1713 #include "sched_fair.c"
1714 #include "sched_rt.c"
1715 #ifdef CONFIG_SCHED_DEBUG
1716 # include "sched_debug.c"
1719 #define sched_class_highest (&rt_sched_class)
1720 #define for_each_class(class) \
1721 for (class = sched_class_highest; class; class = class->next)
1723 static void inc_nr_running(struct rq *rq)
1728 static void dec_nr_running(struct rq *rq)
1733 static void set_load_weight(struct task_struct *p)
1735 if (task_has_rt_policy(p)) {
1736 p->se.load.weight = prio_to_weight[0] * 2;
1737 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1742 * SCHED_IDLE tasks get minimal weight:
1744 if (p->policy == SCHED_IDLE) {
1745 p->se.load.weight = WEIGHT_IDLEPRIO;
1746 p->se.load.inv_weight = WMULT_IDLEPRIO;
1750 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1751 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1754 static void update_avg(u64 *avg, u64 sample)
1756 s64 diff = sample - *avg;
1760 static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
1763 p->se.start_runtime = p->se.sum_exec_runtime;
1765 sched_info_queued(p);
1766 p->sched_class->enqueue_task(rq, p, wakeup);
1770 static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
1773 if (p->se.last_wakeup) {
1774 update_avg(&p->se.avg_overlap,
1775 p->se.sum_exec_runtime - p->se.last_wakeup);
1776 p->se.last_wakeup = 0;
1778 update_avg(&p->se.avg_wakeup,
1779 sysctl_sched_wakeup_granularity);
1783 sched_info_dequeued(p);
1784 p->sched_class->dequeue_task(rq, p, sleep);
1789 * __normal_prio - return the priority that is based on the static prio
1791 static inline int __normal_prio(struct task_struct *p)
1793 return p->static_prio;
1797 * Calculate the expected normal priority: i.e. priority
1798 * without taking RT-inheritance into account. Might be
1799 * boosted by interactivity modifiers. Changes upon fork,
1800 * setprio syscalls, and whenever the interactivity
1801 * estimator recalculates.
1803 static inline int normal_prio(struct task_struct *p)
1807 if (task_has_rt_policy(p))
1808 prio = MAX_RT_PRIO-1 - p->rt_priority;
1810 prio = __normal_prio(p);
1815 * Calculate the current priority, i.e. the priority
1816 * taken into account by the scheduler. This value might
1817 * be boosted by RT tasks, or might be boosted by
1818 * interactivity modifiers. Will be RT if the task got
1819 * RT-boosted. If not then it returns p->normal_prio.
1821 static int effective_prio(struct task_struct *p)
1823 p->normal_prio = normal_prio(p);
1825 * If we are RT tasks or we were boosted to RT priority,
1826 * keep the priority unchanged. Otherwise, update priority
1827 * to the normal priority:
1829 if (!rt_prio(p->prio))
1830 return p->normal_prio;
1835 * activate_task - move a task to the runqueue.
1837 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
1839 if (task_contributes_to_load(p))
1840 rq->nr_uninterruptible--;
1842 enqueue_task(rq, p, wakeup);
1847 * deactivate_task - remove a task from the runqueue.
1849 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
1851 if (task_contributes_to_load(p))
1852 rq->nr_uninterruptible++;
1854 dequeue_task(rq, p, sleep);
1859 * task_curr - is this task currently executing on a CPU?
1860 * @p: the task in question.
1862 inline int task_curr(const struct task_struct *p)
1864 return cpu_curr(task_cpu(p)) == p;
1867 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1869 set_task_rq(p, cpu);
1872 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1873 * successfuly executed on another CPU. We must ensure that updates of
1874 * per-task data have been completed by this moment.
1877 task_thread_info(p)->cpu = cpu;
1881 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1882 const struct sched_class *prev_class,
1883 int oldprio, int running)
1885 if (prev_class != p->sched_class) {
1886 if (prev_class->switched_from)
1887 prev_class->switched_from(rq, p, running);
1888 p->sched_class->switched_to(rq, p, running);
1890 p->sched_class->prio_changed(rq, p, oldprio, running);
1895 /* Used instead of source_load when we know the type == 0 */
1896 static unsigned long weighted_cpuload(const int cpu)
1898 return cpu_rq(cpu)->load.weight;
1902 * Is this task likely cache-hot:
1905 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1910 * Buddy candidates are cache hot:
1912 if (sched_feat(CACHE_HOT_BUDDY) &&
1913 (&p->se == cfs_rq_of(&p->se)->next ||
1914 &p->se == cfs_rq_of(&p->se)->last))
1917 if (p->sched_class != &fair_sched_class)
1920 if (sysctl_sched_migration_cost == -1)
1922 if (sysctl_sched_migration_cost == 0)
1925 delta = now - p->se.exec_start;
1927 return delta < (s64)sysctl_sched_migration_cost;
1931 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1933 int old_cpu = task_cpu(p);
1934 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
1935 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1936 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
1939 clock_offset = old_rq->clock - new_rq->clock;
1941 trace_sched_migrate_task(p, task_cpu(p), new_cpu);
1943 #ifdef CONFIG_SCHEDSTATS
1944 if (p->se.wait_start)
1945 p->se.wait_start -= clock_offset;
1946 if (p->se.sleep_start)
1947 p->se.sleep_start -= clock_offset;
1948 if (p->se.block_start)
1949 p->se.block_start -= clock_offset;
1950 if (old_cpu != new_cpu) {
1951 schedstat_inc(p, se.nr_migrations);
1952 if (task_hot(p, old_rq->clock, NULL))
1953 schedstat_inc(p, se.nr_forced2_migrations);
1956 p->se.vruntime -= old_cfsrq->min_vruntime -
1957 new_cfsrq->min_vruntime;
1959 __set_task_cpu(p, new_cpu);
1962 struct migration_req {
1963 struct list_head list;
1965 struct task_struct *task;
1968 struct completion done;
1972 * The task's runqueue lock must be held.
1973 * Returns true if you have to wait for migration thread.
1976 migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
1978 struct rq *rq = task_rq(p);
1981 * If the task is not on a runqueue (and not running), then
1982 * it is sufficient to simply update the task's cpu field.
1984 if (!p->se.on_rq && !task_running(rq, p)) {
1985 set_task_cpu(p, dest_cpu);
1989 init_completion(&req->done);
1991 req->dest_cpu = dest_cpu;
1992 list_add(&req->list, &rq->migration_queue);
1998 * wait_task_inactive - wait for a thread to unschedule.
2000 * If @match_state is nonzero, it's the @p->state value just checked and
2001 * not expected to change. If it changes, i.e. @p might have woken up,
2002 * then return zero. When we succeed in waiting for @p to be off its CPU,
2003 * we return a positive number (its total switch count). If a second call
2004 * a short while later returns the same number, the caller can be sure that
2005 * @p has remained unscheduled the whole time.
2007 * The caller must ensure that the task *will* unschedule sometime soon,
2008 * else this function might spin for a *long* time. This function can't
2009 * be called with interrupts off, or it may introduce deadlock with
2010 * smp_call_function() if an IPI is sent by the same process we are
2011 * waiting to become inactive.
2013 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
2015 unsigned long flags;
2022 * We do the initial early heuristics without holding
2023 * any task-queue locks at all. We'll only try to get
2024 * the runqueue lock when things look like they will
2030 * If the task is actively running on another CPU
2031 * still, just relax and busy-wait without holding
2034 * NOTE! Since we don't hold any locks, it's not
2035 * even sure that "rq" stays as the right runqueue!
2036 * But we don't care, since "task_running()" will
2037 * return false if the runqueue has changed and p
2038 * is actually now running somewhere else!
2040 while (task_running(rq, p)) {
2041 if (match_state && unlikely(p->state != match_state))
2047 * Ok, time to look more closely! We need the rq
2048 * lock now, to be *sure*. If we're wrong, we'll
2049 * just go back and repeat.
2051 rq = task_rq_lock(p, &flags);
2052 trace_sched_wait_task(rq, p);
2053 running = task_running(rq, p);
2054 on_rq = p->se.on_rq;
2056 if (!match_state || p->state == match_state)
2057 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
2058 task_rq_unlock(rq, &flags);
2061 * If it changed from the expected state, bail out now.
2063 if (unlikely(!ncsw))
2067 * Was it really running after all now that we
2068 * checked with the proper locks actually held?
2070 * Oops. Go back and try again..
2072 if (unlikely(running)) {
2078 * It's not enough that it's not actively running,
2079 * it must be off the runqueue _entirely_, and not
2082 * So if it was still runnable (but just not actively
2083 * running right now), it's preempted, and we should
2084 * yield - it could be a while.
2086 if (unlikely(on_rq)) {
2087 schedule_timeout_uninterruptible(1);
2092 * Ahh, all good. It wasn't running, and it wasn't
2093 * runnable, which means that it will never become
2094 * running in the future either. We're all done!
2103 * kick_process - kick a running thread to enter/exit the kernel
2104 * @p: the to-be-kicked thread
2106 * Cause a process which is running on another CPU to enter
2107 * kernel-mode, without any delay. (to get signals handled.)
2109 * NOTE: this function doesnt have to take the runqueue lock,
2110 * because all it wants to ensure is that the remote task enters
2111 * the kernel. If the IPI races and the task has been migrated
2112 * to another CPU then no harm is done and the purpose has been
2115 void kick_process(struct task_struct *p)
2121 if ((cpu != smp_processor_id()) && task_curr(p))
2122 smp_send_reschedule(cpu);
2127 * Return a low guess at the load of a migration-source cpu weighted
2128 * according to the scheduling class and "nice" value.
2130 * We want to under-estimate the load of migration sources, to
2131 * balance conservatively.
2133 static unsigned long source_load(int cpu, int type)
2135 struct rq *rq = cpu_rq(cpu);
2136 unsigned long total = weighted_cpuload(cpu);
2138 if (type == 0 || !sched_feat(LB_BIAS))
2141 return min(rq->cpu_load[type-1], total);
2145 * Return a high guess at the load of a migration-target cpu weighted
2146 * according to the scheduling class and "nice" value.
2148 static unsigned long target_load(int cpu, int type)
2150 struct rq *rq = cpu_rq(cpu);
2151 unsigned long total = weighted_cpuload(cpu);
2153 if (type == 0 || !sched_feat(LB_BIAS))
2156 return max(rq->cpu_load[type-1], total);
2160 * find_idlest_group finds and returns the least busy CPU group within the
2163 static struct sched_group *
2164 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
2166 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
2167 unsigned long min_load = ULONG_MAX, this_load = 0;
2168 int load_idx = sd->forkexec_idx;
2169 int imbalance = 100 + (sd->imbalance_pct-100)/2;
2172 unsigned long load, avg_load;
2176 /* Skip over this group if it has no CPUs allowed */
2177 if (!cpumask_intersects(sched_group_cpus(group),
2181 local_group = cpumask_test_cpu(this_cpu,
2182 sched_group_cpus(group));
2184 /* Tally up the load of all CPUs in the group */
2187 for_each_cpu(i, sched_group_cpus(group)) {
2188 /* Bias balancing toward cpus of our domain */
2190 load = source_load(i, load_idx);
2192 load = target_load(i, load_idx);
2197 /* Adjust by relative CPU power of the group */
2198 avg_load = sg_div_cpu_power(group,
2199 avg_load * SCHED_LOAD_SCALE);
2202 this_load = avg_load;
2204 } else if (avg_load < min_load) {
2205 min_load = avg_load;
2208 } while (group = group->next, group != sd->groups);
2210 if (!idlest || 100*this_load < imbalance*min_load)
2216 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2219 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
2221 unsigned long load, min_load = ULONG_MAX;
2225 /* Traverse only the allowed CPUs */
2226 for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {
2227 load = weighted_cpuload(i);
2229 if (load < min_load || (load == min_load && i == this_cpu)) {
2239 * sched_balance_self: balance the current task (running on cpu) in domains
2240 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2243 * Balance, ie. select the least loaded group.
2245 * Returns the target CPU number, or the same CPU if no balancing is needed.
2247 * preempt must be disabled.
2249 static int sched_balance_self(int cpu, int flag)
2251 struct task_struct *t = current;
2252 struct sched_domain *tmp, *sd = NULL;
2254 for_each_domain(cpu, tmp) {
2256 * If power savings logic is enabled for a domain, stop there.
2258 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2260 if (tmp->flags & flag)
2268 struct sched_group *group;
2269 int new_cpu, weight;
2271 if (!(sd->flags & flag)) {
2276 group = find_idlest_group(sd, t, cpu);
2282 new_cpu = find_idlest_cpu(group, t, cpu);
2283 if (new_cpu == -1 || new_cpu == cpu) {
2284 /* Now try balancing at a lower domain level of cpu */
2289 /* Now try balancing at a lower domain level of new_cpu */
2291 weight = cpumask_weight(sched_domain_span(sd));
2293 for_each_domain(cpu, tmp) {
2294 if (weight <= cpumask_weight(sched_domain_span(tmp)))
2296 if (tmp->flags & flag)
2299 /* while loop will break here if sd == NULL */
2305 #endif /* CONFIG_SMP */
2308 * try_to_wake_up - wake up a thread
2309 * @p: the to-be-woken-up thread
2310 * @state: the mask of task states that can be woken
2311 * @sync: do a synchronous wakeup?
2313 * Put it on the run-queue if it's not already there. The "current"
2314 * thread is always on the run-queue (except when the actual
2315 * re-schedule is in progress), and as such you're allowed to do
2316 * the simpler "current->state = TASK_RUNNING" to mark yourself
2317 * runnable without the overhead of this.
2319 * returns failure only if the task is already active.
2321 static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
2323 int cpu, orig_cpu, this_cpu, success = 0;
2324 unsigned long flags;
2328 if (!sched_feat(SYNC_WAKEUPS))
2332 if (sched_feat(LB_WAKEUP_UPDATE) && !root_task_group_empty()) {
2333 struct sched_domain *sd;
2335 this_cpu = raw_smp_processor_id();
2338 for_each_domain(this_cpu, sd) {
2339 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2348 rq = task_rq_lock(p, &flags);
2349 update_rq_clock(rq);
2350 old_state = p->state;
2351 if (!(old_state & state))
2359 this_cpu = smp_processor_id();
2362 if (unlikely(task_running(rq, p)))
2365 cpu = p->sched_class->select_task_rq(p, sync);
2366 if (cpu != orig_cpu) {
2367 set_task_cpu(p, cpu);
2368 task_rq_unlock(rq, &flags);
2369 /* might preempt at this point */
2370 rq = task_rq_lock(p, &flags);
2371 old_state = p->state;
2372 if (!(old_state & state))
2377 this_cpu = smp_processor_id();
2381 #ifdef CONFIG_SCHEDSTATS
2382 schedstat_inc(rq, ttwu_count);
2383 if (cpu == this_cpu)
2384 schedstat_inc(rq, ttwu_local);
2386 struct sched_domain *sd;
2387 for_each_domain(this_cpu, sd) {
2388 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2389 schedstat_inc(sd, ttwu_wake_remote);
2394 #endif /* CONFIG_SCHEDSTATS */
2397 #endif /* CONFIG_SMP */
2398 schedstat_inc(p, se.nr_wakeups);
2400 schedstat_inc(p, se.nr_wakeups_sync);
2401 if (orig_cpu != cpu)
2402 schedstat_inc(p, se.nr_wakeups_migrate);
2403 if (cpu == this_cpu)
2404 schedstat_inc(p, se.nr_wakeups_local);
2406 schedstat_inc(p, se.nr_wakeups_remote);
2407 activate_task(rq, p, 1);
2411 * Only attribute actual wakeups done by this task.
2413 if (!in_interrupt()) {
2414 struct sched_entity *se = ¤t->se;
2415 u64 sample = se->sum_exec_runtime;
2417 if (se->last_wakeup)
2418 sample -= se->last_wakeup;
2420 sample -= se->start_runtime;
2421 update_avg(&se->avg_wakeup, sample);
2423 se->last_wakeup = se->sum_exec_runtime;
2427 trace_sched_wakeup(rq, p, success);
2428 check_preempt_curr(rq, p, sync);
2430 p->state = TASK_RUNNING;
2432 if (p->sched_class->task_wake_up)
2433 p->sched_class->task_wake_up(rq, p);
2436 task_rq_unlock(rq, &flags);
2441 int wake_up_process(struct task_struct *p)
2443 return try_to_wake_up(p, TASK_ALL, 0);
2445 EXPORT_SYMBOL(wake_up_process);
2447 int wake_up_state(struct task_struct *p, unsigned int state)
2449 return try_to_wake_up(p, state, 0);
2453 * Perform scheduler related setup for a newly forked process p.
2454 * p is forked by current.
2456 * __sched_fork() is basic setup used by init_idle() too:
2458 static void __sched_fork(struct task_struct *p)
2460 p->se.exec_start = 0;
2461 p->se.sum_exec_runtime = 0;
2462 p->se.prev_sum_exec_runtime = 0;
2463 p->se.last_wakeup = 0;
2464 p->se.avg_overlap = 0;
2465 p->se.start_runtime = 0;
2466 p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
2468 #ifdef CONFIG_SCHEDSTATS
2469 p->se.wait_start = 0;
2470 p->se.sum_sleep_runtime = 0;
2471 p->se.sleep_start = 0;
2472 p->se.block_start = 0;
2473 p->se.sleep_max = 0;
2474 p->se.block_max = 0;
2476 p->se.slice_max = 0;
2480 INIT_LIST_HEAD(&p->rt.run_list);
2482 INIT_LIST_HEAD(&p->se.group_node);
2484 #ifdef CONFIG_PREEMPT_NOTIFIERS
2485 INIT_HLIST_HEAD(&p->preempt_notifiers);
2489 * We mark the process as running here, but have not actually
2490 * inserted it onto the runqueue yet. This guarantees that
2491 * nobody will actually run it, and a signal or other external
2492 * event cannot wake it up and insert it on the runqueue either.
2494 p->state = TASK_RUNNING;
2498 * fork()/clone()-time setup:
2500 void sched_fork(struct task_struct *p, int clone_flags)
2502 int cpu = get_cpu();
2507 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
2509 set_task_cpu(p, cpu);
2512 * Make sure we do not leak PI boosting priority to the child:
2514 p->prio = current->normal_prio;
2515 if (!rt_prio(p->prio))
2516 p->sched_class = &fair_sched_class;
2518 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2519 if (likely(sched_info_on()))
2520 memset(&p->sched_info, 0, sizeof(p->sched_info));
2522 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2525 #ifdef CONFIG_PREEMPT
2526 /* Want to start with kernel preemption disabled. */
2527 task_thread_info(p)->preempt_count = 1;
2529 plist_node_init(&p->pushable_tasks, MAX_PRIO);
2535 * wake_up_new_task - wake up a newly created task for the first time.
2537 * This function will do some initial scheduler statistics housekeeping
2538 * that must be done for every newly created context, then puts the task
2539 * on the runqueue and wakes it.
2541 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2543 unsigned long flags;
2546 rq = task_rq_lock(p, &flags);
2547 BUG_ON(p->state != TASK_RUNNING);
2548 update_rq_clock(rq);
2550 p->prio = effective_prio(p);
2552 if (!p->sched_class->task_new || !current->se.on_rq) {
2553 activate_task(rq, p, 0);
2556 * Let the scheduling class do new task startup
2557 * management (if any):
2559 p->sched_class->task_new(rq, p);
2562 trace_sched_wakeup_new(rq, p, 1);
2563 check_preempt_curr(rq, p, 0);
2565 if (p->sched_class->task_wake_up)
2566 p->sched_class->task_wake_up(rq, p);
2568 task_rq_unlock(rq, &flags);
2571 #ifdef CONFIG_PREEMPT_NOTIFIERS
2574 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2575 * @notifier: notifier struct to register
2577 void preempt_notifier_register(struct preempt_notifier *notifier)
2579 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2581 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2584 * preempt_notifier_unregister - no longer interested in preemption notifications
2585 * @notifier: notifier struct to unregister
2587 * This is safe to call from within a preemption notifier.
2589 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2591 hlist_del(¬ifier->link);
2593 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2595 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2597 struct preempt_notifier *notifier;
2598 struct hlist_node *node;
2600 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2601 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2605 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2606 struct task_struct *next)
2608 struct preempt_notifier *notifier;
2609 struct hlist_node *node;
2611 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2612 notifier->ops->sched_out(notifier, next);
2615 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2617 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2622 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2623 struct task_struct *next)
2627 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2630 * prepare_task_switch - prepare to switch tasks
2631 * @rq: the runqueue preparing to switch
2632 * @prev: the current task that is being switched out
2633 * @next: the task we are going to switch to.
2635 * This is called with the rq lock held and interrupts off. It must
2636 * be paired with a subsequent finish_task_switch after the context
2639 * prepare_task_switch sets up locking and calls architecture specific
2643 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2644 struct task_struct *next)
2646 fire_sched_out_preempt_notifiers(prev, next);
2647 prepare_lock_switch(rq, next);
2648 prepare_arch_switch(next);
2652 * finish_task_switch - clean up after a task-switch
2653 * @rq: runqueue associated with task-switch
2654 * @prev: the thread we just switched away from.
2656 * finish_task_switch must be called after the context switch, paired
2657 * with a prepare_task_switch call before the context switch.
2658 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2659 * and do any other architecture-specific cleanup actions.
2661 * Note that we may have delayed dropping an mm in context_switch(). If
2662 * so, we finish that here outside of the runqueue lock. (Doing it
2663 * with the lock held can cause deadlocks; see schedule() for
2666 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2667 __releases(rq->lock)
2669 struct mm_struct *mm = rq->prev_mm;
2672 int post_schedule = 0;
2674 if (current->sched_class->needs_post_schedule)
2675 post_schedule = current->sched_class->needs_post_schedule(rq);
2681 * A task struct has one reference for the use as "current".
2682 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2683 * schedule one last time. The schedule call will never return, and
2684 * the scheduled task must drop that reference.
2685 * The test for TASK_DEAD must occur while the runqueue locks are
2686 * still held, otherwise prev could be scheduled on another cpu, die
2687 * there before we look at prev->state, and then the reference would
2689 * Manfred Spraul <manfred@colorfullife.com>
2691 prev_state = prev->state;
2692 finish_arch_switch(prev);
2693 finish_lock_switch(rq, prev);
2696 current->sched_class->post_schedule(rq);
2699 fire_sched_in_preempt_notifiers(current);
2702 if (unlikely(prev_state == TASK_DEAD)) {
2704 * Remove function-return probe instances associated with this
2705 * task and put them back on the free list.
2707 kprobe_flush_task(prev);
2708 put_task_struct(prev);
2713 * schedule_tail - first thing a freshly forked thread must call.
2714 * @prev: the thread we just switched away from.
2716 asmlinkage void schedule_tail(struct task_struct *prev)
2717 __releases(rq->lock)
2719 struct rq *rq = this_rq();
2721 finish_task_switch(rq, prev);
2722 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2723 /* In this case, finish_task_switch does not reenable preemption */
2726 if (current->set_child_tid)
2727 put_user(task_pid_vnr(current), current->set_child_tid);
2731 * context_switch - switch to the new MM and the new
2732 * thread's register state.
2735 context_switch(struct rq *rq, struct task_struct *prev,
2736 struct task_struct *next)
2738 struct mm_struct *mm, *oldmm;
2740 prepare_task_switch(rq, prev, next);
2741 trace_sched_switch(rq, prev, next);
2743 oldmm = prev->active_mm;
2745 * For paravirt, this is coupled with an exit in switch_to to
2746 * combine the page table reload and the switch backend into
2749 arch_enter_lazy_cpu_mode();
2751 if (unlikely(!mm)) {
2752 next->active_mm = oldmm;
2753 atomic_inc(&oldmm->mm_count);
2754 enter_lazy_tlb(oldmm, next);
2756 switch_mm(oldmm, mm, next);
2758 if (unlikely(!prev->mm)) {
2759 prev->active_mm = NULL;
2760 rq->prev_mm = oldmm;
2763 * Since the runqueue lock will be released by the next
2764 * task (which is an invalid locking op but in the case
2765 * of the scheduler it's an obvious special-case), so we
2766 * do an early lockdep release here:
2768 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2769 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2772 /* Here we just switch the register state and the stack. */
2773 switch_to(prev, next, prev);
2777 * this_rq must be evaluated again because prev may have moved
2778 * CPUs since it called schedule(), thus the 'rq' on its stack
2779 * frame will be invalid.
2781 finish_task_switch(this_rq(), prev);
2785 * nr_running, nr_uninterruptible and nr_context_switches:
2787 * externally visible scheduler statistics: current number of runnable
2788 * threads, current number of uninterruptible-sleeping threads, total
2789 * number of context switches performed since bootup.
2791 unsigned long nr_running(void)
2793 unsigned long i, sum = 0;
2795 for_each_online_cpu(i)
2796 sum += cpu_rq(i)->nr_running;
2801 unsigned long nr_uninterruptible(void)
2803 unsigned long i, sum = 0;
2805 for_each_possible_cpu(i)
2806 sum += cpu_rq(i)->nr_uninterruptible;
2809 * Since we read the counters lockless, it might be slightly
2810 * inaccurate. Do not allow it to go below zero though:
2812 if (unlikely((long)sum < 0))
2818 unsigned long long nr_context_switches(void)
2821 unsigned long long sum = 0;
2823 for_each_possible_cpu(i)
2824 sum += cpu_rq(i)->nr_switches;
2829 unsigned long nr_iowait(void)
2831 unsigned long i, sum = 0;
2833 for_each_possible_cpu(i)
2834 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2839 unsigned long nr_active(void)
2841 unsigned long i, running = 0, uninterruptible = 0;
2843 for_each_online_cpu(i) {
2844 running += cpu_rq(i)->nr_running;
2845 uninterruptible += cpu_rq(i)->nr_uninterruptible;
2848 if (unlikely((long)uninterruptible < 0))
2849 uninterruptible = 0;
2851 return running + uninterruptible;
2855 * Update rq->cpu_load[] statistics. This function is usually called every
2856 * scheduler tick (TICK_NSEC).
2858 static void update_cpu_load(struct rq *this_rq)
2860 unsigned long this_load = this_rq->load.weight;
2863 this_rq->nr_load_updates++;
2865 /* Update our load: */
2866 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2867 unsigned long old_load, new_load;
2869 /* scale is effectively 1 << i now, and >> i divides by scale */
2871 old_load = this_rq->cpu_load[i];
2872 new_load = this_load;
2874 * Round up the averaging division if load is increasing. This
2875 * prevents us from getting stuck on 9 if the load is 10, for
2878 if (new_load > old_load)
2879 new_load += scale-1;
2880 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
2887 * double_rq_lock - safely lock two runqueues
2889 * Note this does not disable interrupts like task_rq_lock,
2890 * you need to do so manually before calling.
2892 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
2893 __acquires(rq1->lock)
2894 __acquires(rq2->lock)
2896 BUG_ON(!irqs_disabled());
2898 spin_lock(&rq1->lock);
2899 __acquire(rq2->lock); /* Fake it out ;) */
2902 spin_lock(&rq1->lock);
2903 spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
2905 spin_lock(&rq2->lock);
2906 spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
2909 update_rq_clock(rq1);
2910 update_rq_clock(rq2);
2914 * double_rq_unlock - safely unlock two runqueues
2916 * Note this does not restore interrupts like task_rq_unlock,
2917 * you need to do so manually after calling.
2919 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
2920 __releases(rq1->lock)
2921 __releases(rq2->lock)
2923 spin_unlock(&rq1->lock);
2925 spin_unlock(&rq2->lock);
2927 __release(rq2->lock);
2931 * If dest_cpu is allowed for this process, migrate the task to it.
2932 * This is accomplished by forcing the cpu_allowed mask to only
2933 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2934 * the cpu_allowed mask is restored.
2936 static void sched_migrate_task(struct task_struct *p, int dest_cpu)
2938 struct migration_req req;
2939 unsigned long flags;
2942 rq = task_rq_lock(p, &flags);
2943 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)
2944 || unlikely(!cpu_active(dest_cpu)))
2947 /* force the process onto the specified CPU */
2948 if (migrate_task(p, dest_cpu, &req)) {
2949 /* Need to wait for migration thread (might exit: take ref). */
2950 struct task_struct *mt = rq->migration_thread;
2952 get_task_struct(mt);
2953 task_rq_unlock(rq, &flags);
2954 wake_up_process(mt);
2955 put_task_struct(mt);
2956 wait_for_completion(&req.done);
2961 task_rq_unlock(rq, &flags);
2965 * sched_exec - execve() is a valuable balancing opportunity, because at
2966 * this point the task has the smallest effective memory and cache footprint.
2968 void sched_exec(void)
2970 int new_cpu, this_cpu = get_cpu();
2971 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
2973 if (new_cpu != this_cpu)
2974 sched_migrate_task(current, new_cpu);
2978 * pull_task - move a task from a remote runqueue to the local runqueue.
2979 * Both runqueues must be locked.
2981 static void pull_task(struct rq *src_rq, struct task_struct *p,
2982 struct rq *this_rq, int this_cpu)
2984 deactivate_task(src_rq, p, 0);
2985 set_task_cpu(p, this_cpu);
2986 activate_task(this_rq, p, 0);
2988 * Note that idle threads have a prio of MAX_PRIO, for this test
2989 * to be always true for them.
2991 check_preempt_curr(this_rq, p, 0);
2995 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2998 int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
2999 struct sched_domain *sd, enum cpu_idle_type idle,
3002 int tsk_cache_hot = 0;
3004 * We do not migrate tasks that are:
3005 * 1) running (obviously), or
3006 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3007 * 3) are cache-hot on their current CPU.
3009 if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) {
3010 schedstat_inc(p, se.nr_failed_migrations_affine);
3015 if (task_running(rq, p)) {
3016 schedstat_inc(p, se.nr_failed_migrations_running);
3021 * Aggressive migration if:
3022 * 1) task is cache cold, or
3023 * 2) too many balance attempts have failed.
3026 tsk_cache_hot = task_hot(p, rq->clock, sd);
3027 if (!tsk_cache_hot ||
3028 sd->nr_balance_failed > sd->cache_nice_tries) {
3029 #ifdef CONFIG_SCHEDSTATS
3030 if (tsk_cache_hot) {
3031 schedstat_inc(sd, lb_hot_gained[idle]);
3032 schedstat_inc(p, se.nr_forced_migrations);
3038 if (tsk_cache_hot) {
3039 schedstat_inc(p, se.nr_failed_migrations_hot);
3045 static unsigned long
3046 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3047 unsigned long max_load_move, struct sched_domain *sd,
3048 enum cpu_idle_type idle, int *all_pinned,
3049 int *this_best_prio, struct rq_iterator *iterator)
3051 int loops = 0, pulled = 0, pinned = 0;
3052 struct task_struct *p;
3053 long rem_load_move = max_load_move;
3055 if (max_load_move == 0)
3061 * Start the load-balancing iterator:
3063 p = iterator->start(iterator->arg);
3065 if (!p || loops++ > sysctl_sched_nr_migrate)
3068 if ((p->se.load.weight >> 1) > rem_load_move ||
3069 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3070 p = iterator->next(iterator->arg);
3074 pull_task(busiest, p, this_rq, this_cpu);
3076 rem_load_move -= p->se.load.weight;
3078 #ifdef CONFIG_PREEMPT
3080 * NEWIDLE balancing is a source of latency, so preemptible kernels
3081 * will stop after the first task is pulled to minimize the critical
3084 if (idle == CPU_NEWLY_IDLE)
3089 * We only want to steal up to the prescribed amount of weighted load.
3091 if (rem_load_move > 0) {
3092 if (p->prio < *this_best_prio)
3093 *this_best_prio = p->prio;
3094 p = iterator->next(iterator->arg);
3099 * Right now, this is one of only two places pull_task() is called,
3100 * so we can safely collect pull_task() stats here rather than
3101 * inside pull_task().
3103 schedstat_add(sd, lb_gained[idle], pulled);
3106 *all_pinned = pinned;
3108 return max_load_move - rem_load_move;
3112 * move_tasks tries to move up to max_load_move weighted load from busiest to
3113 * this_rq, as part of a balancing operation within domain "sd".
3114 * Returns 1 if successful and 0 otherwise.
3116 * Called with both runqueues locked.
3118 static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3119 unsigned long max_load_move,
3120 struct sched_domain *sd, enum cpu_idle_type idle,
3123 const struct sched_class *class = sched_class_highest;
3124 unsigned long total_load_moved = 0;
3125 int this_best_prio = this_rq->curr->prio;
3129 class->load_balance(this_rq, this_cpu, busiest,
3130 max_load_move - total_load_moved,
3131 sd, idle, all_pinned, &this_best_prio);
3132 class = class->next;
3134 #ifdef CONFIG_PREEMPT
3136 * NEWIDLE balancing is a source of latency, so preemptible
3137 * kernels will stop after the first task is pulled to minimize
3138 * the critical section.
3140 if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
3143 } while (class && max_load_move > total_load_moved);
3145 return total_load_moved > 0;
3149 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3150 struct sched_domain *sd, enum cpu_idle_type idle,
3151 struct rq_iterator *iterator)
3153 struct task_struct *p = iterator->start(iterator->arg);
3157 if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3158 pull_task(busiest, p, this_rq, this_cpu);
3160 * Right now, this is only the second place pull_task()
3161 * is called, so we can safely collect pull_task()
3162 * stats here rather than inside pull_task().
3164 schedstat_inc(sd, lb_gained[idle]);
3168 p = iterator->next(iterator->arg);
3175 * move_one_task tries to move exactly one task from busiest to this_rq, as
3176 * part of active balancing operations within "domain".
3177 * Returns 1 if successful and 0 otherwise.
3179 * Called with both runqueues locked.
3181 static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3182 struct sched_domain *sd, enum cpu_idle_type idle)
3184 const struct sched_class *class;
3186 for (class = sched_class_highest; class; class = class->next)
3187 if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
3192 /********** Helpers for find_busiest_group ************************/
3195 * sg_lb_stats - stats of a sched_group required for load_balancing
3197 struct sg_lb_stats {
3198 unsigned long avg_load; /*Avg load across the CPUs of the group */
3199 unsigned long group_load; /* Total load over the CPUs of the group */
3200 unsigned long sum_nr_running; /* Nr tasks running in the group */
3201 unsigned long sum_weighted_load; /* Weighted load of group's tasks */
3202 unsigned long group_capacity;
3203 int group_imb; /* Is there an imbalance in the group ? */
3207 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3208 * @group: The group whose first cpu is to be returned.
3210 static inline unsigned int group_first_cpu(struct sched_group *group)
3212 return cpumask_first(sched_group_cpus(group));
3216 * get_sd_load_idx - Obtain the load index for a given sched domain.
3217 * @sd: The sched_domain whose load_idx is to be obtained.
3218 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3220 static inline int get_sd_load_idx(struct sched_domain *sd,
3221 enum cpu_idle_type idle)
3227 load_idx = sd->busy_idx;
3230 case CPU_NEWLY_IDLE:
3231 load_idx = sd->newidle_idx;
3234 load_idx = sd->idle_idx;
3243 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3244 * @group: sched_group whose statistics are to be updated.
3245 * @this_cpu: Cpu for which load balance is currently performed.
3246 * @idle: Idle status of this_cpu
3247 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3248 * @sd_idle: Idle status of the sched_domain containing group.
3249 * @local_group: Does group contain this_cpu.
3250 * @cpus: Set of cpus considered for load balancing.
3251 * @balance: Should we balance.
3252 * @sgs: variable to hold the statistics for this group.
3254 static inline void update_sg_lb_stats(struct sched_group *group, int this_cpu,
3255 enum cpu_idle_type idle, int load_idx, int *sd_idle,
3256 int local_group, const struct cpumask *cpus,
3257 int *balance, struct sg_lb_stats *sgs)
3259 unsigned long load, max_cpu_load, min_cpu_load;
3261 unsigned int balance_cpu = -1, first_idle_cpu = 0;
3262 unsigned long sum_avg_load_per_task;
3263 unsigned long avg_load_per_task;
3266 balance_cpu = group_first_cpu(group);
3268 /* Tally up the load of all CPUs in the group */
3269 sum_avg_load_per_task = avg_load_per_task = 0;
3271 min_cpu_load = ~0UL;
3273 for_each_cpu_and(i, sched_group_cpus(group), cpus) {
3274 struct rq *rq = cpu_rq(i);
3276 if (*sd_idle && rq->nr_running)
3279 /* Bias balancing toward cpus of our domain */
3281 if (idle_cpu(i) && !first_idle_cpu) {
3286 load = target_load(i, load_idx);
3288 load = source_load(i, load_idx);
3289 if (load > max_cpu_load)
3290 max_cpu_load = load;
3291 if (min_cpu_load > load)
3292 min_cpu_load = load;
3295 sgs->group_load += load;
3296 sgs->sum_nr_running += rq->nr_running;
3297 sgs->sum_weighted_load += weighted_cpuload(i);
3299 sum_avg_load_per_task += cpu_avg_load_per_task(i);
3303 * First idle cpu or the first cpu(busiest) in this sched group
3304 * is eligible for doing load balancing at this and above
3305 * domains. In the newly idle case, we will allow all the cpu's
3306 * to do the newly idle load balance.
3308 if (idle != CPU_NEWLY_IDLE && local_group &&
3309 balance_cpu != this_cpu && balance) {
3314 /* Adjust by relative CPU power of the group */
3315 sgs->avg_load = sg_div_cpu_power(group,
3316 sgs->group_load * SCHED_LOAD_SCALE);
3320 * Consider the group unbalanced when the imbalance is larger
3321 * than the average weight of two tasks.
3323 * APZ: with cgroup the avg task weight can vary wildly and
3324 * might not be a suitable number - should we keep a
3325 * normalized nr_running number somewhere that negates
3328 avg_load_per_task = sg_div_cpu_power(group,
3329 sum_avg_load_per_task * SCHED_LOAD_SCALE);
3331 if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
3334 sgs->group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
3337 /******* find_busiest_group() helpers end here *********************/
3340 * find_busiest_group finds and returns the busiest CPU group within the
3341 * domain. It calculates and returns the amount of weighted load which
3342 * should be moved to restore balance via the imbalance parameter.
3344 static struct sched_group *
3345 find_busiest_group(struct sched_domain *sd, int this_cpu,
3346 unsigned long *imbalance, enum cpu_idle_type idle,
3347 int *sd_idle, const struct cpumask *cpus, int *balance)
3349 struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
3350 unsigned long max_load, avg_load, total_load, this_load, total_pwr;
3351 unsigned long max_pull;
3352 unsigned long busiest_load_per_task, busiest_nr_running;
3353 unsigned long this_load_per_task, this_nr_running;
3354 int load_idx, group_imb = 0;
3355 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3356 int power_savings_balance = 1;
3357 unsigned long leader_nr_running = 0, min_load_per_task = 0;
3358 unsigned long min_nr_running = ULONG_MAX;
3359 struct sched_group *group_min = NULL, *group_leader = NULL;
3362 max_load = this_load = total_load = total_pwr = 0;
3363 busiest_load_per_task = busiest_nr_running = 0;
3364 this_load_per_task = this_nr_running = 0;
3366 load_idx = get_sd_load_idx(sd, idle);
3369 struct sg_lb_stats sgs;
3372 local_group = cpumask_test_cpu(this_cpu,
3373 sched_group_cpus(group));
3374 memset(&sgs, 0, sizeof(sgs));
3375 update_sg_lb_stats(group, this_cpu, idle, load_idx, sd_idle,
3376 local_group, cpus, balance, &sgs);
3378 if (balance && !(*balance))
3381 total_load += sgs.group_load;
3382 total_pwr += group->__cpu_power;
3385 this_load = sgs.avg_load;
3387 this_nr_running = sgs.sum_nr_running;
3388 this_load_per_task = sgs.sum_weighted_load;
3389 } else if (sgs.avg_load > max_load &&
3390 (sgs.sum_nr_running > sgs.group_capacity ||
3392 max_load = sgs.avg_load;
3394 busiest_nr_running = sgs.sum_nr_running;
3395 busiest_load_per_task = sgs.sum_weighted_load;
3396 group_imb = sgs.group_imb;
3399 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3401 * Busy processors will not participate in power savings
3404 if (idle == CPU_NOT_IDLE ||
3405 !(sd->flags & SD_POWERSAVINGS_BALANCE))
3409 * If the local group is idle or completely loaded
3410 * no need to do power savings balance at this domain
3412 if (local_group && (this_nr_running >= sgs.group_capacity ||
3414 power_savings_balance = 0;
3417 * If a group is already running at full capacity or idle,
3418 * don't include that group in power savings calculations
3420 if (!power_savings_balance ||
3421 sgs.sum_nr_running >= sgs.group_capacity ||
3422 !sgs.sum_nr_running)
3426 * Calculate the group which has the least non-idle load.
3427 * This is the group from where we need to pick up the load
3430 if ((sgs.sum_nr_running < min_nr_running) ||
3431 (sgs.sum_nr_running == min_nr_running &&
3432 group_first_cpu(group) > group_first_cpu(group_min))) {
3434 min_nr_running = sgs.sum_nr_running;
3435 min_load_per_task = sgs.sum_weighted_load /
3440 * Calculate the group which is almost near its
3441 * capacity but still has some space to pick up some load
3442 * from other group and save more power
3444 if (sgs.sum_nr_running > sgs.group_capacity - 1)
3447 if (sgs.sum_nr_running > leader_nr_running ||
3448 (sgs.sum_nr_running == leader_nr_running &&
3449 group_first_cpu(group) < group_first_cpu(group_leader))) {
3450 group_leader = group;
3451 leader_nr_running = sgs.sum_nr_running;
3455 group = group->next;
3456 } while (group != sd->groups);
3458 if (!busiest || this_load >= max_load || busiest_nr_running == 0)
3461 avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
3463 if (this_load >= avg_load ||
3464 100*max_load <= sd->imbalance_pct*this_load)
3467 busiest_load_per_task /= busiest_nr_running;
3469 busiest_load_per_task = min(busiest_load_per_task, avg_load);
3472 * We're trying to get all the cpus to the average_load, so we don't
3473 * want to push ourselves above the average load, nor do we wish to
3474 * reduce the max loaded cpu below the average load, as either of these
3475 * actions would just result in more rebalancing later, and ping-pong
3476 * tasks around. Thus we look for the minimum possible imbalance.
3477 * Negative imbalances (*we* are more loaded than anyone else) will
3478 * be counted as no imbalance for these purposes -- we can't fix that
3479 * by pulling tasks to us. Be careful of negative numbers as they'll
3480 * appear as very large values with unsigned longs.
3482 if (max_load <= busiest_load_per_task)
3486 * In the presence of smp nice balancing, certain scenarios can have
3487 * max load less than avg load(as we skip the groups at or below
3488 * its cpu_power, while calculating max_load..)
3490 if (max_load < avg_load) {
3492 goto small_imbalance;
3495 /* Don't want to pull so many tasks that a group would go idle */
3496 max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
3498 /* How much load to actually move to equalise the imbalance */
3499 *imbalance = min(max_pull * busiest->__cpu_power,
3500 (avg_load - this_load) * this->__cpu_power)
3504 * if *imbalance is less than the average load per runnable task
3505 * there is no gaurantee that any tasks will be moved so we'll have
3506 * a think about bumping its value to force at least one task to be
3509 if (*imbalance < busiest_load_per_task) {
3510 unsigned long tmp, pwr_now, pwr_move;
3514 pwr_move = pwr_now = 0;
3516 if (this_nr_running) {
3517 this_load_per_task /= this_nr_running;
3518 if (busiest_load_per_task > this_load_per_task)
3521 this_load_per_task = cpu_avg_load_per_task(this_cpu);
3523 if (max_load - this_load + busiest_load_per_task >=
3524 busiest_load_per_task * imbn) {
3525 *imbalance = busiest_load_per_task;
3530 * OK, we don't have enough imbalance to justify moving tasks,
3531 * however we may be able to increase total CPU power used by
3535 pwr_now += busiest->__cpu_power *
3536 min(busiest_load_per_task, max_load);
3537 pwr_now += this->__cpu_power *
3538 min(this_load_per_task, this_load);
3539 pwr_now /= SCHED_LOAD_SCALE;
3541 /* Amount of load we'd subtract */
3542 tmp = sg_div_cpu_power(busiest,
3543 busiest_load_per_task * SCHED_LOAD_SCALE);
3545 pwr_move += busiest->__cpu_power *
3546 min(busiest_load_per_task, max_load - tmp);
3548 /* Amount of load we'd add */
3549 if (max_load * busiest->__cpu_power <
3550 busiest_load_per_task * SCHED_LOAD_SCALE)
3551 tmp = sg_div_cpu_power(this,
3552 max_load * busiest->__cpu_power);
3554 tmp = sg_div_cpu_power(this,
3555 busiest_load_per_task * SCHED_LOAD_SCALE);
3556 pwr_move += this->__cpu_power *
3557 min(this_load_per_task, this_load + tmp);
3558 pwr_move /= SCHED_LOAD_SCALE;
3560 /* Move if we gain throughput */
3561 if (pwr_move > pwr_now)
3562 *imbalance = busiest_load_per_task;
3568 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3569 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
3572 if (this != group_leader || group_leader == group_min)
3575 *imbalance = min_load_per_task;
3576 if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
3577 cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
3578 group_first_cpu(group_leader);
3589 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3592 find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
3593 unsigned long imbalance, const struct cpumask *cpus)
3595 struct rq *busiest = NULL, *rq;
3596 unsigned long max_load = 0;
3599 for_each_cpu(i, sched_group_cpus(group)) {
3602 if (!cpumask_test_cpu(i, cpus))
3606 wl = weighted_cpuload(i);
3608 if (rq->nr_running == 1 && wl > imbalance)
3611 if (wl > max_load) {
3621 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3622 * so long as it is large enough.
3624 #define MAX_PINNED_INTERVAL 512
3627 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3628 * tasks if there is an imbalance.
3630 static int load_balance(int this_cpu, struct rq *this_rq,
3631 struct sched_domain *sd, enum cpu_idle_type idle,
3632 int *balance, struct cpumask *cpus)
3634 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
3635 struct sched_group *group;
3636 unsigned long imbalance;
3638 unsigned long flags;
3640 cpumask_setall(cpus);
3643 * When power savings policy is enabled for the parent domain, idle
3644 * sibling can pick up load irrespective of busy siblings. In this case,
3645 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3646 * portraying it as CPU_NOT_IDLE.
3648 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
3649 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3652 schedstat_inc(sd, lb_count[idle]);
3656 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
3663 schedstat_inc(sd, lb_nobusyg[idle]);
3667 busiest = find_busiest_queue(group, idle, imbalance, cpus);
3669 schedstat_inc(sd, lb_nobusyq[idle]);
3673 BUG_ON(busiest == this_rq);
3675 schedstat_add(sd, lb_imbalance[idle], imbalance);
3678 if (busiest->nr_running > 1) {
3680 * Attempt to move tasks. If find_busiest_group has found
3681 * an imbalance but busiest->nr_running <= 1, the group is
3682 * still unbalanced. ld_moved simply stays zero, so it is
3683 * correctly treated as an imbalance.
3685 local_irq_save(flags);
3686 double_rq_lock(this_rq, busiest);
3687 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3688 imbalance, sd, idle, &all_pinned);
3689 double_rq_unlock(this_rq, busiest);
3690 local_irq_restore(flags);
3693 * some other cpu did the load balance for us.
3695 if (ld_moved && this_cpu != smp_processor_id())
3696 resched_cpu(this_cpu);
3698 /* All tasks on this runqueue were pinned by CPU affinity */
3699 if (unlikely(all_pinned)) {
3700 cpumask_clear_cpu(cpu_of(busiest), cpus);
3701 if (!cpumask_empty(cpus))
3708 schedstat_inc(sd, lb_failed[idle]);
3709 sd->nr_balance_failed++;
3711 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
3713 spin_lock_irqsave(&busiest->lock, flags);
3715 /* don't kick the migration_thread, if the curr
3716 * task on busiest cpu can't be moved to this_cpu
3718 if (!cpumask_test_cpu(this_cpu,
3719 &busiest->curr->cpus_allowed)) {
3720 spin_unlock_irqrestore(&busiest->lock, flags);
3722 goto out_one_pinned;
3725 if (!busiest->active_balance) {
3726 busiest->active_balance = 1;
3727 busiest->push_cpu = this_cpu;
3730 spin_unlock_irqrestore(&busiest->lock, flags);
3732 wake_up_process(busiest->migration_thread);
3735 * We've kicked active balancing, reset the failure
3738 sd->nr_balance_failed = sd->cache_nice_tries+1;
3741 sd->nr_balance_failed = 0;
3743 if (likely(!active_balance)) {
3744 /* We were unbalanced, so reset the balancing interval */
3745 sd->balance_interval = sd->min_interval;
3748 * If we've begun active balancing, start to back off. This
3749 * case may not be covered by the all_pinned logic if there
3750 * is only 1 task on the busy runqueue (because we don't call
3753 if (sd->balance_interval < sd->max_interval)
3754 sd->balance_interval *= 2;
3757 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3758 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3764 schedstat_inc(sd, lb_balanced[idle]);
3766 sd->nr_balance_failed = 0;
3769 /* tune up the balancing interval */
3770 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
3771 (sd->balance_interval < sd->max_interval))
3772 sd->balance_interval *= 2;
3774 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3775 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3786 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3787 * tasks if there is an imbalance.
3789 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3790 * this_rq is locked.
3793 load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd,
3794 struct cpumask *cpus)
3796 struct sched_group *group;
3797 struct rq *busiest = NULL;
3798 unsigned long imbalance;
3803 cpumask_setall(cpus);
3806 * When power savings policy is enabled for the parent domain, idle
3807 * sibling can pick up load irrespective of busy siblings. In this case,
3808 * let the state of idle sibling percolate up as IDLE, instead of
3809 * portraying it as CPU_NOT_IDLE.
3811 if (sd->flags & SD_SHARE_CPUPOWER &&
3812 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3815 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
3817 update_shares_locked(this_rq, sd);
3818 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
3819 &sd_idle, cpus, NULL);
3821 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
3825 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
3827 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
3831 BUG_ON(busiest == this_rq);
3833 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
3836 if (busiest->nr_running > 1) {
3837 /* Attempt to move tasks */
3838 double_lock_balance(this_rq, busiest);
3839 /* this_rq->clock is already updated */
3840 update_rq_clock(busiest);
3841 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3842 imbalance, sd, CPU_NEWLY_IDLE,
3844 double_unlock_balance(this_rq, busiest);
3846 if (unlikely(all_pinned)) {
3847 cpumask_clear_cpu(cpu_of(busiest), cpus);
3848 if (!cpumask_empty(cpus))
3854 int active_balance = 0;
3856 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
3857 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3858 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3861 if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
3864 if (sd->nr_balance_failed++ < 2)
3868 * The only task running in a non-idle cpu can be moved to this
3869 * cpu in an attempt to completely freeup the other CPU
3870 * package. The same method used to move task in load_balance()
3871 * have been extended for load_balance_newidle() to speedup
3872 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
3874 * The package power saving logic comes from
3875 * find_busiest_group(). If there are no imbalance, then
3876 * f_b_g() will return NULL. However when sched_mc={1,2} then
3877 * f_b_g() will select a group from which a running task may be
3878 * pulled to this cpu in order to make the other package idle.
3879 * If there is no opportunity to make a package idle and if
3880 * there are no imbalance, then f_b_g() will return NULL and no
3881 * action will be taken in load_balance_newidle().
3883 * Under normal task pull operation due to imbalance, there
3884 * will be more than one task in the source run queue and
3885 * move_tasks() will succeed. ld_moved will be true and this
3886 * active balance code will not be triggered.
3889 /* Lock busiest in correct order while this_rq is held */
3890 double_lock_balance(this_rq, busiest);
3893 * don't kick the migration_thread, if the curr
3894 * task on busiest cpu can't be moved to this_cpu
3896 if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) {
3897 double_unlock_balance(this_rq, busiest);
3902 if (!busiest->active_balance) {
3903 busiest->active_balance = 1;
3904 busiest->push_cpu = this_cpu;
3908 double_unlock_balance(this_rq, busiest);
3910 * Should not call ttwu while holding a rq->lock
3912 spin_unlock(&this_rq->lock);
3914 wake_up_process(busiest->migration_thread);
3915 spin_lock(&this_rq->lock);
3918 sd->nr_balance_failed = 0;
3920 update_shares_locked(this_rq, sd);
3924 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
3925 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3926 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3928 sd->nr_balance_failed = 0;
3934 * idle_balance is called by schedule() if this_cpu is about to become
3935 * idle. Attempts to pull tasks from other CPUs.
3937 static void idle_balance(int this_cpu, struct rq *this_rq)
3939 struct sched_domain *sd;
3940 int pulled_task = 0;
3941 unsigned long next_balance = jiffies + HZ;
3942 cpumask_var_t tmpmask;
3944 if (!alloc_cpumask_var(&tmpmask, GFP_ATOMIC))
3947 for_each_domain(this_cpu, sd) {
3948 unsigned long interval;
3950 if (!(sd->flags & SD_LOAD_BALANCE))
3953 if (sd->flags & SD_BALANCE_NEWIDLE)
3954 /* If we've pulled tasks over stop searching: */
3955 pulled_task = load_balance_newidle(this_cpu, this_rq,
3958 interval = msecs_to_jiffies(sd->balance_interval);
3959 if (time_after(next_balance, sd->last_balance + interval))
3960 next_balance = sd->last_balance + interval;
3964 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
3966 * We are going idle. next_balance may be set based on
3967 * a busy processor. So reset next_balance.
3969 this_rq->next_balance = next_balance;
3971 free_cpumask_var(tmpmask);
3975 * active_load_balance is run by migration threads. It pushes running tasks
3976 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3977 * running on each physical CPU where possible, and avoids physical /
3978 * logical imbalances.
3980 * Called with busiest_rq locked.
3982 static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
3984 int target_cpu = busiest_rq->push_cpu;
3985 struct sched_domain *sd;
3986 struct rq *target_rq;
3988 /* Is there any task to move? */
3989 if (busiest_rq->nr_running <= 1)
3992 target_rq = cpu_rq(target_cpu);
3995 * This condition is "impossible", if it occurs
3996 * we need to fix it. Originally reported by
3997 * Bjorn Helgaas on a 128-cpu setup.
3999 BUG_ON(busiest_rq == target_rq);
4001 /* move a task from busiest_rq to target_rq */
4002 double_lock_balance(busiest_rq, target_rq);
4003 update_rq_clock(busiest_rq);
4004 update_rq_clock(target_rq);
4006 /* Search for an sd spanning us and the target CPU. */
4007 for_each_domain(target_cpu, sd) {
4008 if ((sd->flags & SD_LOAD_BALANCE) &&
4009 cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
4014 schedstat_inc(sd, alb_count);
4016 if (move_one_task(target_rq, target_cpu, busiest_rq,
4018 schedstat_inc(sd, alb_pushed);
4020 schedstat_inc(sd, alb_failed);
4022 double_unlock_balance(busiest_rq, target_rq);
4027 atomic_t load_balancer;
4028 cpumask_var_t cpu_mask;
4029 } nohz ____cacheline_aligned = {
4030 .load_balancer = ATOMIC_INIT(-1),
4034 * This routine will try to nominate the ilb (idle load balancing)
4035 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4036 * load balancing on behalf of all those cpus. If all the cpus in the system
4037 * go into this tickless mode, then there will be no ilb owner (as there is
4038 * no need for one) and all the cpus will sleep till the next wakeup event
4041 * For the ilb owner, tick is not stopped. And this tick will be used
4042 * for idle load balancing. ilb owner will still be part of
4045 * While stopping the tick, this cpu will become the ilb owner if there
4046 * is no other owner. And will be the owner till that cpu becomes busy
4047 * or if all cpus in the system stop their ticks at which point
4048 * there is no need for ilb owner.
4050 * When the ilb owner becomes busy, it nominates another owner, during the
4051 * next busy scheduler_tick()
4053 int select_nohz_load_balancer(int stop_tick)
4055 int cpu = smp_processor_id();
4058 cpu_rq(cpu)->in_nohz_recently = 1;
4060 if (!cpu_active(cpu)) {
4061 if (atomic_read(&nohz.load_balancer) != cpu)
4065 * If we are going offline and still the leader,
4068 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
4074 cpumask_set_cpu(cpu, nohz.cpu_mask);
4076 /* time for ilb owner also to sleep */
4077 if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
4078 if (atomic_read(&nohz.load_balancer) == cpu)
4079 atomic_set(&nohz.load_balancer, -1);
4083 if (atomic_read(&nohz.load_balancer) == -1) {
4084 /* make me the ilb owner */
4085 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
4087 } else if (atomic_read(&nohz.load_balancer) == cpu)
4090 if (!cpumask_test_cpu(cpu, nohz.cpu_mask))
4093 cpumask_clear_cpu(cpu, nohz.cpu_mask);
4095 if (atomic_read(&nohz.load_balancer) == cpu)
4096 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
4103 static DEFINE_SPINLOCK(balancing);
4106 * It checks each scheduling domain to see if it is due to be balanced,
4107 * and initiates a balancing operation if so.
4109 * Balancing parameters are set up in arch_init_sched_domains.
4111 static void rebalance_domains(int cpu, enum cpu_idle_type idle)
4114 struct rq *rq = cpu_rq(cpu);
4115 unsigned long interval;
4116 struct sched_domain *sd;
4117 /* Earliest time when we have to do rebalance again */
4118 unsigned long next_balance = jiffies + 60*HZ;
4119 int update_next_balance = 0;
4123 /* Fails alloc? Rebalancing probably not a priority right now. */
4124 if (!alloc_cpumask_var(&tmp, GFP_ATOMIC))
4127 for_each_domain(cpu, sd) {
4128 if (!(sd->flags & SD_LOAD_BALANCE))
4131 interval = sd->balance_interval;
4132 if (idle != CPU_IDLE)
4133 interval *= sd->busy_factor;
4135 /* scale ms to jiffies */
4136 interval = msecs_to_jiffies(interval);
4137 if (unlikely(!interval))
4139 if (interval > HZ*NR_CPUS/10)
4140 interval = HZ*NR_CPUS/10;
4142 need_serialize = sd->flags & SD_SERIALIZE;
4144 if (need_serialize) {
4145 if (!spin_trylock(&balancing))
4149 if (time_after_eq(jiffies, sd->last_balance + interval)) {
4150 if (load_balance(cpu, rq, sd, idle, &balance, tmp)) {
4152 * We've pulled tasks over so either we're no
4153 * longer idle, or one of our SMT siblings is
4156 idle = CPU_NOT_IDLE;
4158 sd->last_balance = jiffies;
4161 spin_unlock(&balancing);
4163 if (time_after(next_balance, sd->last_balance + interval)) {
4164 next_balance = sd->last_balance + interval;
4165 update_next_balance = 1;
4169 * Stop the load balance at this level. There is another
4170 * CPU in our sched group which is doing load balancing more
4178 * next_balance will be updated only when there is a need.
4179 * When the cpu is attached to null domain for ex, it will not be
4182 if (likely(update_next_balance))
4183 rq->next_balance = next_balance;
4185 free_cpumask_var(tmp);
4189 * run_rebalance_domains is triggered when needed from the scheduler tick.
4190 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4191 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4193 static void run_rebalance_domains(struct softirq_action *h)
4195 int this_cpu = smp_processor_id();
4196 struct rq *this_rq = cpu_rq(this_cpu);
4197 enum cpu_idle_type idle = this_rq->idle_at_tick ?
4198 CPU_IDLE : CPU_NOT_IDLE;
4200 rebalance_domains(this_cpu, idle);
4204 * If this cpu is the owner for idle load balancing, then do the
4205 * balancing on behalf of the other idle cpus whose ticks are
4208 if (this_rq->idle_at_tick &&
4209 atomic_read(&nohz.load_balancer) == this_cpu) {
4213 for_each_cpu(balance_cpu, nohz.cpu_mask) {
4214 if (balance_cpu == this_cpu)
4218 * If this cpu gets work to do, stop the load balancing
4219 * work being done for other cpus. Next load
4220 * balancing owner will pick it up.
4225 rebalance_domains(balance_cpu, CPU_IDLE);
4227 rq = cpu_rq(balance_cpu);
4228 if (time_after(this_rq->next_balance, rq->next_balance))
4229 this_rq->next_balance = rq->next_balance;
4235 static inline int on_null_domain(int cpu)
4237 return !rcu_dereference(cpu_rq(cpu)->sd);
4241 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4243 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4244 * idle load balancing owner or decide to stop the periodic load balancing,
4245 * if the whole system is idle.
4247 static inline void trigger_load_balance(struct rq *rq, int cpu)
4251 * If we were in the nohz mode recently and busy at the current
4252 * scheduler tick, then check if we need to nominate new idle
4255 if (rq->in_nohz_recently && !rq->idle_at_tick) {
4256 rq->in_nohz_recently = 0;
4258 if (atomic_read(&nohz.load_balancer) == cpu) {
4259 cpumask_clear_cpu(cpu, nohz.cpu_mask);
4260 atomic_set(&nohz.load_balancer, -1);
4263 if (atomic_read(&nohz.load_balancer) == -1) {
4265 * simple selection for now: Nominate the
4266 * first cpu in the nohz list to be the next
4269 * TBD: Traverse the sched domains and nominate
4270 * the nearest cpu in the nohz.cpu_mask.
4272 int ilb = cpumask_first(nohz.cpu_mask);
4274 if (ilb < nr_cpu_ids)
4280 * If this cpu is idle and doing idle load balancing for all the
4281 * cpus with ticks stopped, is it time for that to stop?
4283 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
4284 cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
4290 * If this cpu is idle and the idle load balancing is done by
4291 * someone else, then no need raise the SCHED_SOFTIRQ
4293 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
4294 cpumask_test_cpu(cpu, nohz.cpu_mask))
4297 /* Don't need to rebalance while attached to NULL domain */
4298 if (time_after_eq(jiffies, rq->next_balance) &&
4299 likely(!on_null_domain(cpu)))
4300 raise_softirq(SCHED_SOFTIRQ);
4303 #else /* CONFIG_SMP */
4306 * on UP we do not need to balance between CPUs:
4308 static inline void idle_balance(int cpu, struct rq *rq)
4314 DEFINE_PER_CPU(struct kernel_stat, kstat);
4316 EXPORT_PER_CPU_SYMBOL(kstat);
4319 * Return any ns on the sched_clock that have not yet been banked in
4320 * @p in case that task is currently running.
4322 unsigned long long task_delta_exec(struct task_struct *p)
4324 unsigned long flags;
4328 rq = task_rq_lock(p, &flags);
4330 if (task_current(rq, p)) {
4333 update_rq_clock(rq);
4334 delta_exec = rq->clock - p->se.exec_start;
4335 if ((s64)delta_exec > 0)
4339 task_rq_unlock(rq, &flags);
4345 * Account user cpu time to a process.
4346 * @p: the process that the cpu time gets accounted to
4347 * @cputime: the cpu time spent in user space since the last update
4348 * @cputime_scaled: cputime scaled by cpu frequency
4350 void account_user_time(struct task_struct *p, cputime_t cputime,
4351 cputime_t cputime_scaled)
4353 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4356 /* Add user time to process. */
4357 p->utime = cputime_add(p->utime, cputime);
4358 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4359 account_group_user_time(p, cputime);
4361 /* Add user time to cpustat. */
4362 tmp = cputime_to_cputime64(cputime);
4363 if (TASK_NICE(p) > 0)
4364 cpustat->nice = cputime64_add(cpustat->nice, tmp);
4366 cpustat->user = cputime64_add(cpustat->user, tmp);
4367 /* Account for user time used */
4368 acct_update_integrals(p);
4372 * Account guest cpu time to a process.
4373 * @p: the process that the cpu time gets accounted to
4374 * @cputime: the cpu time spent in virtual machine since the last update
4375 * @cputime_scaled: cputime scaled by cpu frequency
4377 static void account_guest_time(struct task_struct *p, cputime_t cputime,
4378 cputime_t cputime_scaled)
4381 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4383 tmp = cputime_to_cputime64(cputime);
4385 /* Add guest time to process. */
4386 p->utime = cputime_add(p->utime, cputime);
4387 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4388 account_group_user_time(p, cputime);
4389 p->gtime = cputime_add(p->gtime, cputime);
4391 /* Add guest time to cpustat. */
4392 cpustat->user = cputime64_add(cpustat->user, tmp);
4393 cpustat->guest = cputime64_add(cpustat->guest, tmp);
4397 * Account system cpu time to a process.
4398 * @p: the process that the cpu time gets accounted to
4399 * @hardirq_offset: the offset to subtract from hardirq_count()
4400 * @cputime: the cpu time spent in kernel space since the last update
4401 * @cputime_scaled: cputime scaled by cpu frequency
4403 void account_system_time(struct task_struct *p, int hardirq_offset,
4404 cputime_t cputime, cputime_t cputime_scaled)
4406 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4409 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
4410 account_guest_time(p, cputime, cputime_scaled);
4414 /* Add system time to process. */
4415 p->stime = cputime_add(p->stime, cputime);
4416 p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
4417 account_group_system_time(p, cputime);
4419 /* Add system time to cpustat. */
4420 tmp = cputime_to_cputime64(cputime);
4421 if (hardirq_count() - hardirq_offset)
4422 cpustat->irq = cputime64_add(cpustat->irq, tmp);
4423 else if (softirq_count())
4424 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
4426 cpustat->system = cputime64_add(cpustat->system, tmp);
4428 /* Account for system time used */
4429 acct_update_integrals(p);
4433 * Account for involuntary wait time.
4434 * @steal: the cpu time spent in involuntary wait
4436 void account_steal_time(cputime_t cputime)
4438 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4439 cputime64_t cputime64 = cputime_to_cputime64(cputime);
4441 cpustat->steal = cputime64_add(cpustat->steal, cputime64);
4445 * Account for idle time.
4446 * @cputime: the cpu time spent in idle wait
4448 void account_idle_time(cputime_t cputime)
4450 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4451 cputime64_t cputime64 = cputime_to_cputime64(cputime);
4452 struct rq *rq = this_rq();
4454 if (atomic_read(&rq->nr_iowait) > 0)
4455 cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
4457 cpustat->idle = cputime64_add(cpustat->idle, cputime64);
4460 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4463 * Account a single tick of cpu time.
4464 * @p: the process that the cpu time gets accounted to
4465 * @user_tick: indicates if the tick is a user or a system tick
4467 void account_process_tick(struct task_struct *p, int user_tick)
4469 cputime_t one_jiffy = jiffies_to_cputime(1);
4470 cputime_t one_jiffy_scaled = cputime_to_scaled(one_jiffy);
4471 struct rq *rq = this_rq();
4474 account_user_time(p, one_jiffy, one_jiffy_scaled);
4475 else if (p != rq->idle)
4476 account_system_time(p, HARDIRQ_OFFSET, one_jiffy,
4479 account_idle_time(one_jiffy);
4483 * Account multiple ticks of steal time.
4484 * @p: the process from which the cpu time has been stolen
4485 * @ticks: number of stolen ticks
4487 void account_steal_ticks(unsigned long ticks)
4489 account_steal_time(jiffies_to_cputime(ticks));
4493 * Account multiple ticks of idle time.
4494 * @ticks: number of stolen ticks
4496 void account_idle_ticks(unsigned long ticks)
4498 account_idle_time(jiffies_to_cputime(ticks));
4504 * Use precise platform statistics if available:
4506 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4507 cputime_t task_utime(struct task_struct *p)
4512 cputime_t task_stime(struct task_struct *p)
4517 cputime_t task_utime(struct task_struct *p)
4519 clock_t utime = cputime_to_clock_t(p->utime),
4520 total = utime + cputime_to_clock_t(p->stime);
4524 * Use CFS's precise accounting:
4526 temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
4530 do_div(temp, total);
4532 utime = (clock_t)temp;
4534 p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
4535 return p->prev_utime;
4538 cputime_t task_stime(struct task_struct *p)
4543 * Use CFS's precise accounting. (we subtract utime from
4544 * the total, to make sure the total observed by userspace
4545 * grows monotonically - apps rely on that):
4547 stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
4548 cputime_to_clock_t(task_utime(p));
4551 p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime));
4553 return p->prev_stime;
4557 inline cputime_t task_gtime(struct task_struct *p)
4563 * This function gets called by the timer code, with HZ frequency.
4564 * We call it with interrupts disabled.
4566 * It also gets called by the fork code, when changing the parent's
4569 void scheduler_tick(void)
4571 int cpu = smp_processor_id();
4572 struct rq *rq = cpu_rq(cpu);
4573 struct task_struct *curr = rq->curr;
4577 spin_lock(&rq->lock);
4578 update_rq_clock(rq);
4579 update_cpu_load(rq);
4580 curr->sched_class->task_tick(rq, curr, 0);
4581 spin_unlock(&rq->lock);
4584 rq->idle_at_tick = idle_cpu(cpu);
4585 trigger_load_balance(rq, cpu);
4589 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4590 defined(CONFIG_PREEMPT_TRACER))
4592 static inline unsigned long get_parent_ip(unsigned long addr)
4594 if (in_lock_functions(addr)) {
4595 addr = CALLER_ADDR2;
4596 if (in_lock_functions(addr))
4597 addr = CALLER_ADDR3;
4602 void __kprobes add_preempt_count(int val)
4604 #ifdef CONFIG_DEBUG_PREEMPT
4608 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4611 preempt_count() += val;
4612 #ifdef CONFIG_DEBUG_PREEMPT
4614 * Spinlock count overflowing soon?
4616 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
4619 if (preempt_count() == val)
4620 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4622 EXPORT_SYMBOL(add_preempt_count);
4624 void __kprobes sub_preempt_count(int val)
4626 #ifdef CONFIG_DEBUG_PREEMPT
4630 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
4633 * Is the spinlock portion underflowing?
4635 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
4636 !(preempt_count() & PREEMPT_MASK)))
4640 if (preempt_count() == val)
4641 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4642 preempt_count() -= val;
4644 EXPORT_SYMBOL(sub_preempt_count);
4649 * Print scheduling while atomic bug:
4651 static noinline void __schedule_bug(struct task_struct *prev)
4653 struct pt_regs *regs = get_irq_regs();
4655 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
4656 prev->comm, prev->pid, preempt_count());
4658 debug_show_held_locks(prev);
4660 if (irqs_disabled())
4661 print_irqtrace_events(prev);
4670 * Various schedule()-time debugging checks and statistics:
4672 static inline void schedule_debug(struct task_struct *prev)
4675 * Test if we are atomic. Since do_exit() needs to call into
4676 * schedule() atomically, we ignore that path for now.
4677 * Otherwise, whine if we are scheduling when we should not be.
4679 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
4680 __schedule_bug(prev);
4682 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
4684 schedstat_inc(this_rq(), sched_count);
4685 #ifdef CONFIG_SCHEDSTATS
4686 if (unlikely(prev->lock_depth >= 0)) {
4687 schedstat_inc(this_rq(), bkl_count);
4688 schedstat_inc(prev, sched_info.bkl_count);
4693 static void put_prev_task(struct rq *rq, struct task_struct *prev)
4695 if (prev->state == TASK_RUNNING) {
4696 u64 runtime = prev->se.sum_exec_runtime;
4698 runtime -= prev->se.prev_sum_exec_runtime;
4699 runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
4702 * In order to avoid avg_overlap growing stale when we are
4703 * indeed overlapping and hence not getting put to sleep, grow
4704 * the avg_overlap on preemption.
4706 * We use the average preemption runtime because that
4707 * correlates to the amount of cache footprint a task can
4710 update_avg(&prev->se.avg_overlap, runtime);
4712 prev->sched_class->put_prev_task(rq, prev);
4716 * Pick up the highest-prio task:
4718 static inline struct task_struct *
4719 pick_next_task(struct rq *rq)
4721 const struct sched_class *class;
4722 struct task_struct *p;
4725 * Optimization: we know that if all tasks are in
4726 * the fair class we can call that function directly:
4728 if (likely(rq->nr_running == rq->cfs.nr_running)) {
4729 p = fair_sched_class.pick_next_task(rq);
4734 class = sched_class_highest;
4736 p = class->pick_next_task(rq);
4740 * Will never be NULL as the idle class always
4741 * returns a non-NULL p:
4743 class = class->next;
4748 * schedule() is the main scheduler function.
4750 asmlinkage void __sched schedule(void)
4752 struct task_struct *prev, *next;
4753 unsigned long *switch_count;
4759 cpu = smp_processor_id();
4763 switch_count = &prev->nivcsw;
4765 release_kernel_lock(prev);
4766 need_resched_nonpreemptible:
4768 schedule_debug(prev);
4770 if (sched_feat(HRTICK))
4773 spin_lock_irq(&rq->lock);
4774 update_rq_clock(rq);
4775 clear_tsk_need_resched(prev);
4777 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
4778 if (unlikely(signal_pending_state(prev->state, prev)))
4779 prev->state = TASK_RUNNING;
4781 deactivate_task(rq, prev, 1);
4782 switch_count = &prev->nvcsw;
4786 if (prev->sched_class->pre_schedule)
4787 prev->sched_class->pre_schedule(rq, prev);
4790 if (unlikely(!rq->nr_running))
4791 idle_balance(cpu, rq);
4793 put_prev_task(rq, prev);
4794 next = pick_next_task(rq);
4796 if (likely(prev != next)) {
4797 sched_info_switch(prev, next);
4803 context_switch(rq, prev, next); /* unlocks the rq */
4805 * the context switch might have flipped the stack from under
4806 * us, hence refresh the local variables.
4808 cpu = smp_processor_id();
4811 spin_unlock_irq(&rq->lock);
4813 if (unlikely(reacquire_kernel_lock(current) < 0))
4814 goto need_resched_nonpreemptible;
4816 preempt_enable_no_resched();
4817 if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
4820 EXPORT_SYMBOL(schedule);
4822 #ifdef CONFIG_PREEMPT
4824 * this is the entry point to schedule() from in-kernel preemption
4825 * off of preempt_enable. Kernel preemptions off return from interrupt
4826 * occur there and call schedule directly.
4828 asmlinkage void __sched preempt_schedule(void)
4830 struct thread_info *ti = current_thread_info();
4833 * If there is a non-zero preempt_count or interrupts are disabled,
4834 * we do not want to preempt the current task. Just return..
4836 if (likely(ti->preempt_count || irqs_disabled()))
4840 add_preempt_count(PREEMPT_ACTIVE);
4842 sub_preempt_count(PREEMPT_ACTIVE);
4845 * Check again in case we missed a preemption opportunity
4846 * between schedule and now.
4849 } while (need_resched());
4851 EXPORT_SYMBOL(preempt_schedule);
4854 * this is the entry point to schedule() from kernel preemption
4855 * off of irq context.
4856 * Note, that this is called and return with irqs disabled. This will
4857 * protect us against recursive calling from irq.
4859 asmlinkage void __sched preempt_schedule_irq(void)
4861 struct thread_info *ti = current_thread_info();
4863 /* Catch callers which need to be fixed */
4864 BUG_ON(ti->preempt_count || !irqs_disabled());
4867 add_preempt_count(PREEMPT_ACTIVE);
4870 local_irq_disable();
4871 sub_preempt_count(PREEMPT_ACTIVE);
4874 * Check again in case we missed a preemption opportunity
4875 * between schedule and now.
4878 } while (need_resched());
4881 #endif /* CONFIG_PREEMPT */
4883 int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
4886 return try_to_wake_up(curr->private, mode, sync);
4888 EXPORT_SYMBOL(default_wake_function);
4891 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4892 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4893 * number) then we wake all the non-exclusive tasks and one exclusive task.
4895 * There are circumstances in which we can try to wake a task which has already
4896 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4897 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4899 void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
4900 int nr_exclusive, int sync, void *key)
4902 wait_queue_t *curr, *next;
4904 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
4905 unsigned flags = curr->flags;
4907 if (curr->func(curr, mode, sync, key) &&
4908 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
4914 * __wake_up - wake up threads blocked on a waitqueue.
4916 * @mode: which threads
4917 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4918 * @key: is directly passed to the wakeup function
4920 void __wake_up(wait_queue_head_t *q, unsigned int mode,
4921 int nr_exclusive, void *key)
4923 unsigned long flags;
4925 spin_lock_irqsave(&q->lock, flags);
4926 __wake_up_common(q, mode, nr_exclusive, 0, key);
4927 spin_unlock_irqrestore(&q->lock, flags);
4929 EXPORT_SYMBOL(__wake_up);
4932 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4934 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
4936 __wake_up_common(q, mode, 1, 0, NULL);
4940 * __wake_up_sync - wake up threads blocked on a waitqueue.
4942 * @mode: which threads
4943 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4945 * The sync wakeup differs that the waker knows that it will schedule
4946 * away soon, so while the target thread will be woken up, it will not
4947 * be migrated to another CPU - ie. the two threads are 'synchronized'
4948 * with each other. This can prevent needless bouncing between CPUs.
4950 * On UP it can prevent extra preemption.
4953 __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
4955 unsigned long flags;
4961 if (unlikely(!nr_exclusive))
4964 spin_lock_irqsave(&q->lock, flags);
4965 __wake_up_common(q, mode, nr_exclusive, sync, NULL);
4966 spin_unlock_irqrestore(&q->lock, flags);
4968 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
4971 * complete: - signals a single thread waiting on this completion
4972 * @x: holds the state of this particular completion
4974 * This will wake up a single thread waiting on this completion. Threads will be
4975 * awakened in the same order in which they were queued.
4977 * See also complete_all(), wait_for_completion() and related routines.
4979 void complete(struct completion *x)
4981 unsigned long flags;
4983 spin_lock_irqsave(&x->wait.lock, flags);
4985 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
4986 spin_unlock_irqrestore(&x->wait.lock, flags);
4988 EXPORT_SYMBOL(complete);
4991 * complete_all: - signals all threads waiting on this completion
4992 * @x: holds the state of this particular completion
4994 * This will wake up all threads waiting on this particular completion event.
4996 void complete_all(struct completion *x)
4998 unsigned long flags;
5000 spin_lock_irqsave(&x->wait.lock, flags);
5001 x->done += UINT_MAX/2;
5002 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
5003 spin_unlock_irqrestore(&x->wait.lock, flags);
5005 EXPORT_SYMBOL(complete_all);
5007 static inline long __sched
5008 do_wait_for_common(struct completion *x, long timeout, int state)
5011 DECLARE_WAITQUEUE(wait, current);
5013 wait.flags |= WQ_FLAG_EXCLUSIVE;
5014 __add_wait_queue_tail(&x->wait, &wait);
5016 if (signal_pending_state(state, current)) {
5017 timeout = -ERESTARTSYS;
5020 __set_current_state(state);
5021 spin_unlock_irq(&x->wait.lock);
5022 timeout = schedule_timeout(timeout);
5023 spin_lock_irq(&x->wait.lock);
5024 } while (!x->done && timeout);
5025 __remove_wait_queue(&x->wait, &wait);
5030 return timeout ?: 1;
5034 wait_for_common(struct completion *x, long timeout, int state)
5038 spin_lock_irq(&x->wait.lock);
5039 timeout = do_wait_for_common(x, timeout, state);
5040 spin_unlock_irq(&x->wait.lock);
5045 * wait_for_completion: - waits for completion of a task
5046 * @x: holds the state of this particular completion
5048 * This waits to be signaled for completion of a specific task. It is NOT
5049 * interruptible and there is no timeout.
5051 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5052 * and interrupt capability. Also see complete().
5054 void __sched wait_for_completion(struct completion *x)
5056 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
5058 EXPORT_SYMBOL(wait_for_completion);
5061 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5062 * @x: holds the state of this particular completion
5063 * @timeout: timeout value in jiffies
5065 * This waits for either a completion of a specific task to be signaled or for a
5066 * specified timeout to expire. The timeout is in jiffies. It is not
5069 unsigned long __sched
5070 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
5072 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
5074 EXPORT_SYMBOL(wait_for_completion_timeout);
5077 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5078 * @x: holds the state of this particular completion
5080 * This waits for completion of a specific task to be signaled. It is
5083 int __sched wait_for_completion_interruptible(struct completion *x)
5085 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
5086 if (t == -ERESTARTSYS)
5090 EXPORT_SYMBOL(wait_for_completion_interruptible);
5093 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5094 * @x: holds the state of this particular completion
5095 * @timeout: timeout value in jiffies
5097 * This waits for either a completion of a specific task to be signaled or for a
5098 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5100 unsigned long __sched
5101 wait_for_completion_interruptible_timeout(struct completion *x,
5102 unsigned long timeout)
5104 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
5106 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
5109 * wait_for_completion_killable: - waits for completion of a task (killable)
5110 * @x: holds the state of this particular completion
5112 * This waits to be signaled for completion of a specific task. It can be
5113 * interrupted by a kill signal.
5115 int __sched wait_for_completion_killable(struct completion *x)
5117 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
5118 if (t == -ERESTARTSYS)
5122 EXPORT_SYMBOL(wait_for_completion_killable);
5125 * try_wait_for_completion - try to decrement a completion without blocking
5126 * @x: completion structure
5128 * Returns: 0 if a decrement cannot be done without blocking
5129 * 1 if a decrement succeeded.
5131 * If a completion is being used as a counting completion,
5132 * attempt to decrement the counter without blocking. This
5133 * enables us to avoid waiting if the resource the completion
5134 * is protecting is not available.
5136 bool try_wait_for_completion(struct completion *x)
5140 spin_lock_irq(&x->wait.lock);
5145 spin_unlock_irq(&x->wait.lock);
5148 EXPORT_SYMBOL(try_wait_for_completion);
5151 * completion_done - Test to see if a completion has any waiters
5152 * @x: completion structure
5154 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5155 * 1 if there are no waiters.
5158 bool completion_done(struct completion *x)
5162 spin_lock_irq(&x->wait.lock);
5165 spin_unlock_irq(&x->wait.lock);
5168 EXPORT_SYMBOL(completion_done);
5171 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
5173 unsigned long flags;
5176 init_waitqueue_entry(&wait, current);
5178 __set_current_state(state);
5180 spin_lock_irqsave(&q->lock, flags);
5181 __add_wait_queue(q, &wait);
5182 spin_unlock(&q->lock);
5183 timeout = schedule_timeout(timeout);
5184 spin_lock_irq(&q->lock);
5185 __remove_wait_queue(q, &wait);
5186 spin_unlock_irqrestore(&q->lock, flags);
5191 void __sched interruptible_sleep_on(wait_queue_head_t *q)
5193 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
5195 EXPORT_SYMBOL(interruptible_sleep_on);
5198 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
5200 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
5202 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
5204 void __sched sleep_on(wait_queue_head_t *q)
5206 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
5208 EXPORT_SYMBOL(sleep_on);
5210 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
5212 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
5214 EXPORT_SYMBOL(sleep_on_timeout);
5216 #ifdef CONFIG_RT_MUTEXES
5219 * rt_mutex_setprio - set the current priority of a task
5221 * @prio: prio value (kernel-internal form)
5223 * This function changes the 'effective' priority of a task. It does
5224 * not touch ->normal_prio like __setscheduler().
5226 * Used by the rt_mutex code to implement priority inheritance logic.
5228 void rt_mutex_setprio(struct task_struct *p, int prio)
5230 unsigned long flags;
5231 int oldprio, on_rq, running;
5233 const struct sched_class *prev_class = p->sched_class;
5235 BUG_ON(prio < 0 || prio > MAX_PRIO);
5237 rq = task_rq_lock(p, &flags);
5238 update_rq_clock(rq);
5241 on_rq = p->se.on_rq;
5242 running = task_current(rq, p);
5244 dequeue_task(rq, p, 0);
5246 p->sched_class->put_prev_task(rq, p);
5249 p->sched_class = &rt_sched_class;
5251 p->sched_class = &fair_sched_class;
5256 p->sched_class->set_curr_task(rq);
5258 enqueue_task(rq, p, 0);
5260 check_class_changed(rq, p, prev_class, oldprio, running);
5262 task_rq_unlock(rq, &flags);
5267 void set_user_nice(struct task_struct *p, long nice)
5269 int old_prio, delta, on_rq;
5270 unsigned long flags;
5273 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
5276 * We have to be careful, if called from sys_setpriority(),
5277 * the task might be in the middle of scheduling on another CPU.
5279 rq = task_rq_lock(p, &flags);
5280 update_rq_clock(rq);
5282 * The RT priorities are set via sched_setscheduler(), but we still
5283 * allow the 'normal' nice value to be set - but as expected
5284 * it wont have any effect on scheduling until the task is
5285 * SCHED_FIFO/SCHED_RR:
5287 if (task_has_rt_policy(p)) {
5288 p->static_prio = NICE_TO_PRIO(nice);
5291 on_rq = p->se.on_rq;
5293 dequeue_task(rq, p, 0);
5295 p->static_prio = NICE_TO_PRIO(nice);
5298 p->prio = effective_prio(p);
5299 delta = p->prio - old_prio;
5302 enqueue_task(rq, p, 0);
5304 * If the task increased its priority or is running and
5305 * lowered its priority, then reschedule its CPU:
5307 if (delta < 0 || (delta > 0 && task_running(rq, p)))
5308 resched_task(rq->curr);
5311 task_rq_unlock(rq, &flags);
5313 EXPORT_SYMBOL(set_user_nice);
5316 * can_nice - check if a task can reduce its nice value
5320 int can_nice(const struct task_struct *p, const int nice)
5322 /* convert nice value [19,-20] to rlimit style value [1,40] */
5323 int nice_rlim = 20 - nice;
5325 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
5326 capable(CAP_SYS_NICE));
5329 #ifdef __ARCH_WANT_SYS_NICE
5332 * sys_nice - change the priority of the current process.
5333 * @increment: priority increment
5335 * sys_setpriority is a more generic, but much slower function that
5336 * does similar things.
5338 SYSCALL_DEFINE1(nice, int, increment)
5343 * Setpriority might change our priority at the same moment.
5344 * We don't have to worry. Conceptually one call occurs first
5345 * and we have a single winner.
5347 if (increment < -40)
5352 nice = TASK_NICE(current) + increment;
5358 if (increment < 0 && !can_nice(current, nice))
5361 retval = security_task_setnice(current, nice);
5365 set_user_nice(current, nice);
5372 * task_prio - return the priority value of a given task.
5373 * @p: the task in question.
5375 * This is the priority value as seen by users in /proc.
5376 * RT tasks are offset by -200. Normal tasks are centered
5377 * around 0, value goes from -16 to +15.
5379 int task_prio(const struct task_struct *p)
5381 return p->prio - MAX_RT_PRIO;
5385 * task_nice - return the nice value of a given task.
5386 * @p: the task in question.
5388 int task_nice(const struct task_struct *p)
5390 return TASK_NICE(p);
5392 EXPORT_SYMBOL(task_nice);
5395 * idle_cpu - is a given cpu idle currently?
5396 * @cpu: the processor in question.
5398 int idle_cpu(int cpu)
5400 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
5404 * idle_task - return the idle task for a given cpu.
5405 * @cpu: the processor in question.
5407 struct task_struct *idle_task(int cpu)
5409 return cpu_rq(cpu)->idle;
5413 * find_process_by_pid - find a process with a matching PID value.
5414 * @pid: the pid in question.
5416 static struct task_struct *find_process_by_pid(pid_t pid)
5418 return pid ? find_task_by_vpid(pid) : current;
5421 /* Actually do priority change: must hold rq lock. */
5423 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
5425 BUG_ON(p->se.on_rq);
5428 switch (p->policy) {
5432 p->sched_class = &fair_sched_class;
5436 p->sched_class = &rt_sched_class;
5440 p->rt_priority = prio;
5441 p->normal_prio = normal_prio(p);
5442 /* we are holding p->pi_lock already */
5443 p->prio = rt_mutex_getprio(p);
5448 * check the target process has a UID that matches the current process's
5450 static bool check_same_owner(struct task_struct *p)
5452 const struct cred *cred = current_cred(), *pcred;
5456 pcred = __task_cred(p);
5457 match = (cred->euid == pcred->euid ||
5458 cred->euid == pcred->uid);
5463 static int __sched_setscheduler(struct task_struct *p, int policy,
5464 struct sched_param *param, bool user)
5466 int retval, oldprio, oldpolicy = -1, on_rq, running;
5467 unsigned long flags;
5468 const struct sched_class *prev_class = p->sched_class;
5471 /* may grab non-irq protected spin_locks */
5472 BUG_ON(in_interrupt());
5474 /* double check policy once rq lock held */
5476 policy = oldpolicy = p->policy;
5477 else if (policy != SCHED_FIFO && policy != SCHED_RR &&
5478 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
5479 policy != SCHED_IDLE)
5482 * Valid priorities for SCHED_FIFO and SCHED_RR are
5483 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5484 * SCHED_BATCH and SCHED_IDLE is 0.
5486 if (param->sched_priority < 0 ||
5487 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
5488 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
5490 if (rt_policy(policy) != (param->sched_priority != 0))
5494 * Allow unprivileged RT tasks to decrease priority:
5496 if (user && !capable(CAP_SYS_NICE)) {
5497 if (rt_policy(policy)) {
5498 unsigned long rlim_rtprio;
5500 if (!lock_task_sighand(p, &flags))
5502 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
5503 unlock_task_sighand(p, &flags);
5505 /* can't set/change the rt policy */
5506 if (policy != p->policy && !rlim_rtprio)
5509 /* can't increase priority */
5510 if (param->sched_priority > p->rt_priority &&
5511 param->sched_priority > rlim_rtprio)
5515 * Like positive nice levels, dont allow tasks to
5516 * move out of SCHED_IDLE either:
5518 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
5521 /* can't change other user's priorities */
5522 if (!check_same_owner(p))
5527 #ifdef CONFIG_RT_GROUP_SCHED
5529 * Do not allow realtime tasks into groups that have no runtime
5532 if (rt_bandwidth_enabled() && rt_policy(policy) &&
5533 task_group(p)->rt_bandwidth.rt_runtime == 0)
5537 retval = security_task_setscheduler(p, policy, param);
5543 * make sure no PI-waiters arrive (or leave) while we are
5544 * changing the priority of the task:
5546 spin_lock_irqsave(&p->pi_lock, flags);
5548 * To be able to change p->policy safely, the apropriate
5549 * runqueue lock must be held.
5551 rq = __task_rq_lock(p);
5552 /* recheck policy now with rq lock held */
5553 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
5554 policy = oldpolicy = -1;
5555 __task_rq_unlock(rq);
5556 spin_unlock_irqrestore(&p->pi_lock, flags);
5559 update_rq_clock(rq);
5560 on_rq = p->se.on_rq;
5561 running = task_current(rq, p);
5563 deactivate_task(rq, p, 0);
5565 p->sched_class->put_prev_task(rq, p);
5568 __setscheduler(rq, p, policy, param->sched_priority);
5571 p->sched_class->set_curr_task(rq);
5573 activate_task(rq, p, 0);
5575 check_class_changed(rq, p, prev_class, oldprio, running);
5577 __task_rq_unlock(rq);
5578 spin_unlock_irqrestore(&p->pi_lock, flags);
5580 rt_mutex_adjust_pi(p);
5586 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5587 * @p: the task in question.
5588 * @policy: new policy.
5589 * @param: structure containing the new RT priority.
5591 * NOTE that the task may be already dead.
5593 int sched_setscheduler(struct task_struct *p, int policy,
5594 struct sched_param *param)
5596 return __sched_setscheduler(p, policy, param, true);
5598 EXPORT_SYMBOL_GPL(sched_setscheduler);
5601 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5602 * @p: the task in question.
5603 * @policy: new policy.
5604 * @param: structure containing the new RT priority.
5606 * Just like sched_setscheduler, only don't bother checking if the
5607 * current context has permission. For example, this is needed in
5608 * stop_machine(): we create temporary high priority worker threads,
5609 * but our caller might not have that capability.
5611 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
5612 struct sched_param *param)
5614 return __sched_setscheduler(p, policy, param, false);
5618 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5620 struct sched_param lparam;
5621 struct task_struct *p;
5624 if (!param || pid < 0)
5626 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
5631 p = find_process_by_pid(pid);
5633 retval = sched_setscheduler(p, policy, &lparam);
5640 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5641 * @pid: the pid in question.
5642 * @policy: new policy.
5643 * @param: structure containing the new RT priority.
5645 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
5646 struct sched_param __user *, param)
5648 /* negative values for policy are not valid */
5652 return do_sched_setscheduler(pid, policy, param);
5656 * sys_sched_setparam - set/change the RT priority of a thread
5657 * @pid: the pid in question.
5658 * @param: structure containing the new RT priority.
5660 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
5662 return do_sched_setscheduler(pid, -1, param);
5666 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5667 * @pid: the pid in question.
5669 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
5671 struct task_struct *p;
5678 read_lock(&tasklist_lock);
5679 p = find_process_by_pid(pid);
5681 retval = security_task_getscheduler(p);
5685 read_unlock(&tasklist_lock);
5690 * sys_sched_getscheduler - get the RT priority of a thread
5691 * @pid: the pid in question.
5692 * @param: structure containing the RT priority.
5694 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
5696 struct sched_param lp;
5697 struct task_struct *p;
5700 if (!param || pid < 0)
5703 read_lock(&tasklist_lock);
5704 p = find_process_by_pid(pid);
5709 retval = security_task_getscheduler(p);
5713 lp.sched_priority = p->rt_priority;
5714 read_unlock(&tasklist_lock);
5717 * This one might sleep, we cannot do it with a spinlock held ...
5719 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
5724 read_unlock(&tasklist_lock);
5728 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
5730 cpumask_var_t cpus_allowed, new_mask;
5731 struct task_struct *p;
5735 read_lock(&tasklist_lock);
5737 p = find_process_by_pid(pid);
5739 read_unlock(&tasklist_lock);
5745 * It is not safe to call set_cpus_allowed with the
5746 * tasklist_lock held. We will bump the task_struct's
5747 * usage count and then drop tasklist_lock.
5750 read_unlock(&tasklist_lock);
5752 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
5756 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
5758 goto out_free_cpus_allowed;
5761 if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
5764 retval = security_task_setscheduler(p, 0, NULL);
5768 cpuset_cpus_allowed(p, cpus_allowed);
5769 cpumask_and(new_mask, in_mask, cpus_allowed);
5771 retval = set_cpus_allowed_ptr(p, new_mask);
5774 cpuset_cpus_allowed(p, cpus_allowed);
5775 if (!cpumask_subset(new_mask, cpus_allowed)) {
5777 * We must have raced with a concurrent cpuset
5778 * update. Just reset the cpus_allowed to the
5779 * cpuset's cpus_allowed
5781 cpumask_copy(new_mask, cpus_allowed);
5786 free_cpumask_var(new_mask);
5787 out_free_cpus_allowed:
5788 free_cpumask_var(cpus_allowed);
5795 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
5796 struct cpumask *new_mask)
5798 if (len < cpumask_size())
5799 cpumask_clear(new_mask);
5800 else if (len > cpumask_size())
5801 len = cpumask_size();
5803 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
5807 * sys_sched_setaffinity - set the cpu affinity of a process
5808 * @pid: pid of the process
5809 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5810 * @user_mask_ptr: user-space pointer to the new cpu mask
5812 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
5813 unsigned long __user *, user_mask_ptr)
5815 cpumask_var_t new_mask;
5818 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
5821 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
5823 retval = sched_setaffinity(pid, new_mask);
5824 free_cpumask_var(new_mask);
5828 long sched_getaffinity(pid_t pid, struct cpumask *mask)
5830 struct task_struct *p;
5834 read_lock(&tasklist_lock);
5837 p = find_process_by_pid(pid);
5841 retval = security_task_getscheduler(p);
5845 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
5848 read_unlock(&tasklist_lock);
5855 * sys_sched_getaffinity - get the cpu affinity of a process
5856 * @pid: pid of the process
5857 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5858 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5860 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
5861 unsigned long __user *, user_mask_ptr)
5866 if (len < cpumask_size())
5869 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
5872 ret = sched_getaffinity(pid, mask);
5874 if (copy_to_user(user_mask_ptr, mask, cpumask_size()))
5877 ret = cpumask_size();
5879 free_cpumask_var(mask);
5885 * sys_sched_yield - yield the current processor to other threads.
5887 * This function yields the current CPU to other tasks. If there are no
5888 * other threads running on this CPU then this function will return.
5890 SYSCALL_DEFINE0(sched_yield)
5892 struct rq *rq = this_rq_lock();
5894 schedstat_inc(rq, yld_count);
5895 current->sched_class->yield_task(rq);
5898 * Since we are going to call schedule() anyway, there's
5899 * no need to preempt or enable interrupts:
5901 __release(rq->lock);
5902 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
5903 _raw_spin_unlock(&rq->lock);
5904 preempt_enable_no_resched();
5911 static void __cond_resched(void)
5913 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5914 __might_sleep(__FILE__, __LINE__);
5917 * The BKS might be reacquired before we have dropped
5918 * PREEMPT_ACTIVE, which could trigger a second
5919 * cond_resched() call.
5922 add_preempt_count(PREEMPT_ACTIVE);
5924 sub_preempt_count(PREEMPT_ACTIVE);
5925 } while (need_resched());
5928 int __sched _cond_resched(void)
5930 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
5931 system_state == SYSTEM_RUNNING) {
5937 EXPORT_SYMBOL(_cond_resched);
5940 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5941 * call schedule, and on return reacquire the lock.
5943 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5944 * operations here to prevent schedule() from being called twice (once via
5945 * spin_unlock(), once by hand).
5947 int cond_resched_lock(spinlock_t *lock)
5949 int resched = need_resched() && system_state == SYSTEM_RUNNING;
5952 if (spin_needbreak(lock) || resched) {
5954 if (resched && need_resched())
5963 EXPORT_SYMBOL(cond_resched_lock);
5965 int __sched cond_resched_softirq(void)
5967 BUG_ON(!in_softirq());
5969 if (need_resched() && system_state == SYSTEM_RUNNING) {
5977 EXPORT_SYMBOL(cond_resched_softirq);
5980 * yield - yield the current processor to other threads.
5982 * This is a shortcut for kernel-space yielding - it marks the
5983 * thread runnable and calls sys_sched_yield().
5985 void __sched yield(void)
5987 set_current_state(TASK_RUNNING);
5990 EXPORT_SYMBOL(yield);
5993 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5994 * that process accounting knows that this is a task in IO wait state.
5996 * But don't do that if it is a deliberate, throttling IO wait (this task
5997 * has set its backing_dev_info: the queue against which it should throttle)
5999 void __sched io_schedule(void)
6001 struct rq *rq = &__raw_get_cpu_var(runqueues);
6003 delayacct_blkio_start();
6004 atomic_inc(&rq->nr_iowait);
6006 atomic_dec(&rq->nr_iowait);
6007 delayacct_blkio_end();
6009 EXPORT_SYMBOL(io_schedule);
6011 long __sched io_schedule_timeout(long timeout)
6013 struct rq *rq = &__raw_get_cpu_var(runqueues);
6016 delayacct_blkio_start();
6017 atomic_inc(&rq->nr_iowait);
6018 ret = schedule_timeout(timeout);
6019 atomic_dec(&rq->nr_iowait);
6020 delayacct_blkio_end();
6025 * sys_sched_get_priority_max - return maximum RT priority.
6026 * @policy: scheduling class.
6028 * this syscall returns the maximum rt_priority that can be used
6029 * by a given scheduling class.
6031 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
6038 ret = MAX_USER_RT_PRIO-1;
6050 * sys_sched_get_priority_min - return minimum RT priority.
6051 * @policy: scheduling class.
6053 * this syscall returns the minimum rt_priority that can be used
6054 * by a given scheduling class.
6056 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
6074 * sys_sched_rr_get_interval - return the default timeslice of a process.
6075 * @pid: pid of the process.
6076 * @interval: userspace pointer to the timeslice value.
6078 * this syscall writes the default timeslice value of a given process
6079 * into the user-space timespec buffer. A value of '0' means infinity.
6081 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
6082 struct timespec __user *, interval)
6084 struct task_struct *p;
6085 unsigned int time_slice;
6093 read_lock(&tasklist_lock);
6094 p = find_process_by_pid(pid);
6098 retval = security_task_getscheduler(p);
6103 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6104 * tasks that are on an otherwise idle runqueue:
6107 if (p->policy == SCHED_RR) {
6108 time_slice = DEF_TIMESLICE;
6109 } else if (p->policy != SCHED_FIFO) {
6110 struct sched_entity *se = &p->se;
6111 unsigned long flags;
6114 rq = task_rq_lock(p, &flags);
6115 if (rq->cfs.load.weight)
6116 time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
6117 task_rq_unlock(rq, &flags);
6119 read_unlock(&tasklist_lock);
6120 jiffies_to_timespec(time_slice, &t);
6121 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
6125 read_unlock(&tasklist_lock);
6129 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
6131 void sched_show_task(struct task_struct *p)
6133 unsigned long free = 0;
6136 state = p->state ? __ffs(p->state) + 1 : 0;
6137 printk(KERN_INFO "%-13.13s %c", p->comm,
6138 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
6139 #if BITS_PER_LONG == 32
6140 if (state == TASK_RUNNING)
6141 printk(KERN_CONT " running ");
6143 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
6145 if (state == TASK_RUNNING)
6146 printk(KERN_CONT " running task ");
6148 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
6150 #ifdef CONFIG_DEBUG_STACK_USAGE
6152 unsigned long *n = end_of_stack(p);
6155 free = (unsigned long)n - (unsigned long)end_of_stack(p);
6158 printk(KERN_CONT "%5lu %5d %6d\n", free,
6159 task_pid_nr(p), task_pid_nr(p->real_parent));
6161 show_stack(p, NULL);
6164 void show_state_filter(unsigned long state_filter)
6166 struct task_struct *g, *p;
6168 #if BITS_PER_LONG == 32
6170 " task PC stack pid father\n");
6173 " task PC stack pid father\n");
6175 read_lock(&tasklist_lock);
6176 do_each_thread(g, p) {
6178 * reset the NMI-timeout, listing all files on a slow
6179 * console might take alot of time:
6181 touch_nmi_watchdog();
6182 if (!state_filter || (p->state & state_filter))
6184 } while_each_thread(g, p);
6186 touch_all_softlockup_watchdogs();
6188 #ifdef CONFIG_SCHED_DEBUG
6189 sysrq_sched_debug_show();
6191 read_unlock(&tasklist_lock);
6193 * Only show locks if all tasks are dumped:
6195 if (state_filter == -1)
6196 debug_show_all_locks();
6199 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
6201 idle->sched_class = &idle_sched_class;
6205 * init_idle - set up an idle thread for a given CPU
6206 * @idle: task in question
6207 * @cpu: cpu the idle task belongs to
6209 * NOTE: this function does not set the idle thread's NEED_RESCHED
6210 * flag, to make booting more robust.
6212 void __cpuinit init_idle(struct task_struct *idle, int cpu)
6214 struct rq *rq = cpu_rq(cpu);
6215 unsigned long flags;
6217 spin_lock_irqsave(&rq->lock, flags);
6220 idle->se.exec_start = sched_clock();
6222 idle->prio = idle->normal_prio = MAX_PRIO;
6223 cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
6224 __set_task_cpu(idle, cpu);
6226 rq->curr = rq->idle = idle;
6227 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6230 spin_unlock_irqrestore(&rq->lock, flags);
6232 /* Set the preempt count _outside_ the spinlocks! */
6233 #if defined(CONFIG_PREEMPT)
6234 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
6236 task_thread_info(idle)->preempt_count = 0;
6239 * The idle tasks have their own, simple scheduling class:
6241 idle->sched_class = &idle_sched_class;
6242 ftrace_graph_init_task(idle);
6246 * In a system that switches off the HZ timer nohz_cpu_mask
6247 * indicates which cpus entered this state. This is used
6248 * in the rcu update to wait only for active cpus. For system
6249 * which do not switch off the HZ timer nohz_cpu_mask should
6250 * always be CPU_BITS_NONE.
6252 cpumask_var_t nohz_cpu_mask;
6255 * Increase the granularity value when there are more CPUs,
6256 * because with more CPUs the 'effective latency' as visible
6257 * to users decreases. But the relationship is not linear,
6258 * so pick a second-best guess by going with the log2 of the
6261 * This idea comes from the SD scheduler of Con Kolivas:
6263 static inline void sched_init_granularity(void)
6265 unsigned int factor = 1 + ilog2(num_online_cpus());
6266 const unsigned long limit = 200000000;
6268 sysctl_sched_min_granularity *= factor;
6269 if (sysctl_sched_min_granularity > limit)
6270 sysctl_sched_min_granularity = limit;
6272 sysctl_sched_latency *= factor;
6273 if (sysctl_sched_latency > limit)
6274 sysctl_sched_latency = limit;
6276 sysctl_sched_wakeup_granularity *= factor;
6278 sysctl_sched_shares_ratelimit *= factor;
6283 * This is how migration works:
6285 * 1) we queue a struct migration_req structure in the source CPU's
6286 * runqueue and wake up that CPU's migration thread.
6287 * 2) we down() the locked semaphore => thread blocks.
6288 * 3) migration thread wakes up (implicitly it forces the migrated
6289 * thread off the CPU)
6290 * 4) it gets the migration request and checks whether the migrated
6291 * task is still in the wrong runqueue.
6292 * 5) if it's in the wrong runqueue then the migration thread removes
6293 * it and puts it into the right queue.
6294 * 6) migration thread up()s the semaphore.
6295 * 7) we wake up and the migration is done.
6299 * Change a given task's CPU affinity. Migrate the thread to a
6300 * proper CPU and schedule it away if the CPU it's executing on
6301 * is removed from the allowed bitmask.
6303 * NOTE: the caller must have a valid reference to the task, the
6304 * task must not exit() & deallocate itself prematurely. The
6305 * call is not atomic; no spinlocks may be held.
6307 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
6309 struct migration_req req;
6310 unsigned long flags;
6314 rq = task_rq_lock(p, &flags);
6315 if (!cpumask_intersects(new_mask, cpu_online_mask)) {
6320 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
6321 !cpumask_equal(&p->cpus_allowed, new_mask))) {
6326 if (p->sched_class->set_cpus_allowed)
6327 p->sched_class->set_cpus_allowed(p, new_mask);
6329 cpumask_copy(&p->cpus_allowed, new_mask);
6330 p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
6333 /* Can the task run on the task's current CPU? If so, we're done */
6334 if (cpumask_test_cpu(task_cpu(p), new_mask))
6337 if (migrate_task(p, cpumask_any_and(cpu_online_mask, new_mask), &req)) {
6338 /* Need help from migration thread: drop lock and wait. */
6339 task_rq_unlock(rq, &flags);
6340 wake_up_process(rq->migration_thread);
6341 wait_for_completion(&req.done);
6342 tlb_migrate_finish(p->mm);
6346 task_rq_unlock(rq, &flags);
6350 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
6353 * Move (not current) task off this cpu, onto dest cpu. We're doing
6354 * this because either it can't run here any more (set_cpus_allowed()
6355 * away from this CPU, or CPU going down), or because we're
6356 * attempting to rebalance this task on exec (sched_exec).
6358 * So we race with normal scheduler movements, but that's OK, as long
6359 * as the task is no longer on this CPU.
6361 * Returns non-zero if task was successfully migrated.
6363 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
6365 struct rq *rq_dest, *rq_src;
6368 if (unlikely(!cpu_active(dest_cpu)))
6371 rq_src = cpu_rq(src_cpu);
6372 rq_dest = cpu_rq(dest_cpu);
6374 double_rq_lock(rq_src, rq_dest);
6375 /* Already moved. */
6376 if (task_cpu(p) != src_cpu)
6378 /* Affinity changed (again). */
6379 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
6382 on_rq = p->se.on_rq;
6384 deactivate_task(rq_src, p, 0);
6386 set_task_cpu(p, dest_cpu);
6388 activate_task(rq_dest, p, 0);
6389 check_preempt_curr(rq_dest, p, 0);
6394 double_rq_unlock(rq_src, rq_dest);
6399 * migration_thread - this is a highprio system thread that performs
6400 * thread migration by bumping thread off CPU then 'pushing' onto
6403 static int migration_thread(void *data)
6405 int cpu = (long)data;
6409 BUG_ON(rq->migration_thread != current);
6411 set_current_state(TASK_INTERRUPTIBLE);
6412 while (!kthread_should_stop()) {
6413 struct migration_req *req;
6414 struct list_head *head;
6416 spin_lock_irq(&rq->lock);
6418 if (cpu_is_offline(cpu)) {
6419 spin_unlock_irq(&rq->lock);
6423 if (rq->active_balance) {
6424 active_load_balance(rq, cpu);
6425 rq->active_balance = 0;
6428 head = &rq->migration_queue;
6430 if (list_empty(head)) {
6431 spin_unlock_irq(&rq->lock);
6433 set_current_state(TASK_INTERRUPTIBLE);
6436 req = list_entry(head->next, struct migration_req, list);
6437 list_del_init(head->next);
6439 spin_unlock(&rq->lock);
6440 __migrate_task(req->task, cpu, req->dest_cpu);
6443 complete(&req->done);
6445 __set_current_state(TASK_RUNNING);
6449 /* Wait for kthread_stop */
6450 set_current_state(TASK_INTERRUPTIBLE);
6451 while (!kthread_should_stop()) {
6453 set_current_state(TASK_INTERRUPTIBLE);
6455 __set_current_state(TASK_RUNNING);
6459 #ifdef CONFIG_HOTPLUG_CPU
6461 static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
6465 local_irq_disable();
6466 ret = __migrate_task(p, src_cpu, dest_cpu);
6472 * Figure out where task on dead CPU should go, use force if necessary.
6474 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
6477 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(dead_cpu));
6480 /* Look for allowed, online CPU in same node. */
6481 for_each_cpu_and(dest_cpu, nodemask, cpu_online_mask)
6482 if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
6485 /* Any allowed, online CPU? */
6486 dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_online_mask);
6487 if (dest_cpu < nr_cpu_ids)
6490 /* No more Mr. Nice Guy. */
6491 if (dest_cpu >= nr_cpu_ids) {
6492 cpuset_cpus_allowed_locked(p, &p->cpus_allowed);
6493 dest_cpu = cpumask_any_and(cpu_online_mask, &p->cpus_allowed);
6496 * Don't tell them about moving exiting tasks or
6497 * kernel threads (both mm NULL), since they never
6500 if (p->mm && printk_ratelimit()) {
6501 printk(KERN_INFO "process %d (%s) no "
6502 "longer affine to cpu%d\n",
6503 task_pid_nr(p), p->comm, dead_cpu);
6508 /* It can have affinity changed while we were choosing. */
6509 if (unlikely(!__migrate_task_irq(p, dead_cpu, dest_cpu)))
6514 * While a dead CPU has no uninterruptible tasks queued at this point,
6515 * it might still have a nonzero ->nr_uninterruptible counter, because
6516 * for performance reasons the counter is not stricly tracking tasks to
6517 * their home CPUs. So we just add the counter to another CPU's counter,
6518 * to keep the global sum constant after CPU-down:
6520 static void migrate_nr_uninterruptible(struct rq *rq_src)
6522 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_online_mask));
6523 unsigned long flags;
6525 local_irq_save(flags);
6526 double_rq_lock(rq_src, rq_dest);
6527 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
6528 rq_src->nr_uninterruptible = 0;
6529 double_rq_unlock(rq_src, rq_dest);
6530 local_irq_restore(flags);
6533 /* Run through task list and migrate tasks from the dead cpu. */
6534 static void migrate_live_tasks(int src_cpu)
6536 struct task_struct *p, *t;
6538 read_lock(&tasklist_lock);
6540 do_each_thread(t, p) {
6544 if (task_cpu(p) == src_cpu)
6545 move_task_off_dead_cpu(src_cpu, p);
6546 } while_each_thread(t, p);
6548 read_unlock(&tasklist_lock);
6552 * Schedules idle task to be the next runnable task on current CPU.
6553 * It does so by boosting its priority to highest possible.
6554 * Used by CPU offline code.
6556 void sched_idle_next(void)
6558 int this_cpu = smp_processor_id();
6559 struct rq *rq = cpu_rq(this_cpu);
6560 struct task_struct *p = rq->idle;
6561 unsigned long flags;
6563 /* cpu has to be offline */
6564 BUG_ON(cpu_online(this_cpu));
6567 * Strictly not necessary since rest of the CPUs are stopped by now
6568 * and interrupts disabled on the current cpu.
6570 spin_lock_irqsave(&rq->lock, flags);
6572 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6574 update_rq_clock(rq);
6575 activate_task(rq, p, 0);
6577 spin_unlock_irqrestore(&rq->lock, flags);
6581 * Ensures that the idle task is using init_mm right before its cpu goes
6584 void idle_task_exit(void)
6586 struct mm_struct *mm = current->active_mm;
6588 BUG_ON(cpu_online(smp_processor_id()));
6591 switch_mm(mm, &init_mm, current);
6595 /* called under rq->lock with disabled interrupts */
6596 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
6598 struct rq *rq = cpu_rq(dead_cpu);
6600 /* Must be exiting, otherwise would be on tasklist. */
6601 BUG_ON(!p->exit_state);
6603 /* Cannot have done final schedule yet: would have vanished. */
6604 BUG_ON(p->state == TASK_DEAD);
6609 * Drop lock around migration; if someone else moves it,
6610 * that's OK. No task can be added to this CPU, so iteration is
6613 spin_unlock_irq(&rq->lock);
6614 move_task_off_dead_cpu(dead_cpu, p);
6615 spin_lock_irq(&rq->lock);
6620 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6621 static void migrate_dead_tasks(unsigned int dead_cpu)
6623 struct rq *rq = cpu_rq(dead_cpu);
6624 struct task_struct *next;
6627 if (!rq->nr_running)
6629 update_rq_clock(rq);
6630 next = pick_next_task(rq);
6633 next->sched_class->put_prev_task(rq, next);
6634 migrate_dead(dead_cpu, next);
6638 #endif /* CONFIG_HOTPLUG_CPU */
6640 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6642 static struct ctl_table sd_ctl_dir[] = {
6644 .procname = "sched_domain",
6650 static struct ctl_table sd_ctl_root[] = {
6652 .ctl_name = CTL_KERN,
6653 .procname = "kernel",
6655 .child = sd_ctl_dir,
6660 static struct ctl_table *sd_alloc_ctl_entry(int n)
6662 struct ctl_table *entry =
6663 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
6668 static void sd_free_ctl_entry(struct ctl_table **tablep)
6670 struct ctl_table *entry;
6673 * In the intermediate directories, both the child directory and
6674 * procname are dynamically allocated and could fail but the mode
6675 * will always be set. In the lowest directory the names are
6676 * static strings and all have proc handlers.
6678 for (entry = *tablep; entry->mode; entry++) {
6680 sd_free_ctl_entry(&entry->child);
6681 if (entry->proc_handler == NULL)
6682 kfree(entry->procname);
6690 set_table_entry(struct ctl_table *entry,
6691 const char *procname, void *data, int maxlen,
6692 mode_t mode, proc_handler *proc_handler)
6694 entry->procname = procname;
6696 entry->maxlen = maxlen;
6698 entry->proc_handler = proc_handler;
6701 static struct ctl_table *
6702 sd_alloc_ctl_domain_table(struct sched_domain *sd)
6704 struct ctl_table *table = sd_alloc_ctl_entry(13);
6709 set_table_entry(&table[0], "min_interval", &sd->min_interval,
6710 sizeof(long), 0644, proc_doulongvec_minmax);
6711 set_table_entry(&table[1], "max_interval", &sd->max_interval,
6712 sizeof(long), 0644, proc_doulongvec_minmax);
6713 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
6714 sizeof(int), 0644, proc_dointvec_minmax);
6715 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
6716 sizeof(int), 0644, proc_dointvec_minmax);
6717 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
6718 sizeof(int), 0644, proc_dointvec_minmax);
6719 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
6720 sizeof(int), 0644, proc_dointvec_minmax);
6721 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
6722 sizeof(int), 0644, proc_dointvec_minmax);
6723 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
6724 sizeof(int), 0644, proc_dointvec_minmax);
6725 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
6726 sizeof(int), 0644, proc_dointvec_minmax);
6727 set_table_entry(&table[9], "cache_nice_tries",
6728 &sd->cache_nice_tries,
6729 sizeof(int), 0644, proc_dointvec_minmax);
6730 set_table_entry(&table[10], "flags", &sd->flags,
6731 sizeof(int), 0644, proc_dointvec_minmax);
6732 set_table_entry(&table[11], "name", sd->name,
6733 CORENAME_MAX_SIZE, 0444, proc_dostring);
6734 /* &table[12] is terminator */
6739 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
6741 struct ctl_table *entry, *table;
6742 struct sched_domain *sd;
6743 int domain_num = 0, i;
6746 for_each_domain(cpu, sd)
6748 entry = table = sd_alloc_ctl_entry(domain_num + 1);
6753 for_each_domain(cpu, sd) {
6754 snprintf(buf, 32, "domain%d", i);
6755 entry->procname = kstrdup(buf, GFP_KERNEL);
6757 entry->child = sd_alloc_ctl_domain_table(sd);
6764 static struct ctl_table_header *sd_sysctl_header;
6765 static void register_sched_domain_sysctl(void)
6767 int i, cpu_num = num_online_cpus();
6768 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
6771 WARN_ON(sd_ctl_dir[0].child);
6772 sd_ctl_dir[0].child = entry;
6777 for_each_online_cpu(i) {
6778 snprintf(buf, 32, "cpu%d", i);
6779 entry->procname = kstrdup(buf, GFP_KERNEL);
6781 entry->child = sd_alloc_ctl_cpu_table(i);
6785 WARN_ON(sd_sysctl_header);
6786 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
6789 /* may be called multiple times per register */
6790 static void unregister_sched_domain_sysctl(void)
6792 if (sd_sysctl_header)
6793 unregister_sysctl_table(sd_sysctl_header);
6794 sd_sysctl_header = NULL;
6795 if (sd_ctl_dir[0].child)
6796 sd_free_ctl_entry(&sd_ctl_dir[0].child);
6799 static void register_sched_domain_sysctl(void)
6802 static void unregister_sched_domain_sysctl(void)
6807 static void set_rq_online(struct rq *rq)
6810 const struct sched_class *class;
6812 cpumask_set_cpu(rq->cpu, rq->rd->online);
6815 for_each_class(class) {
6816 if (class->rq_online)
6817 class->rq_online(rq);
6822 static void set_rq_offline(struct rq *rq)
6825 const struct sched_class *class;
6827 for_each_class(class) {
6828 if (class->rq_offline)
6829 class->rq_offline(rq);
6832 cpumask_clear_cpu(rq->cpu, rq->rd->online);
6838 * migration_call - callback that gets triggered when a CPU is added.
6839 * Here we can start up the necessary migration thread for the new CPU.
6841 static int __cpuinit
6842 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
6844 struct task_struct *p;
6845 int cpu = (long)hcpu;
6846 unsigned long flags;
6851 case CPU_UP_PREPARE:
6852 case CPU_UP_PREPARE_FROZEN:
6853 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
6856 kthread_bind(p, cpu);
6857 /* Must be high prio: stop_machine expects to yield to it. */
6858 rq = task_rq_lock(p, &flags);
6859 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6860 task_rq_unlock(rq, &flags);
6861 cpu_rq(cpu)->migration_thread = p;
6865 case CPU_ONLINE_FROZEN:
6866 /* Strictly unnecessary, as first user will wake it. */
6867 wake_up_process(cpu_rq(cpu)->migration_thread);
6869 /* Update our root-domain */
6871 spin_lock_irqsave(&rq->lock, flags);
6873 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
6877 spin_unlock_irqrestore(&rq->lock, flags);
6880 #ifdef CONFIG_HOTPLUG_CPU
6881 case CPU_UP_CANCELED:
6882 case CPU_UP_CANCELED_FROZEN:
6883 if (!cpu_rq(cpu)->migration_thread)
6885 /* Unbind it from offline cpu so it can run. Fall thru. */
6886 kthread_bind(cpu_rq(cpu)->migration_thread,
6887 cpumask_any(cpu_online_mask));
6888 kthread_stop(cpu_rq(cpu)->migration_thread);
6889 cpu_rq(cpu)->migration_thread = NULL;
6893 case CPU_DEAD_FROZEN:
6894 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6895 migrate_live_tasks(cpu);
6897 kthread_stop(rq->migration_thread);
6898 rq->migration_thread = NULL;
6899 /* Idle task back to normal (off runqueue, low prio) */
6900 spin_lock_irq(&rq->lock);
6901 update_rq_clock(rq);
6902 deactivate_task(rq, rq->idle, 0);
6903 rq->idle->static_prio = MAX_PRIO;
6904 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
6905 rq->idle->sched_class = &idle_sched_class;
6906 migrate_dead_tasks(cpu);
6907 spin_unlock_irq(&rq->lock);
6909 migrate_nr_uninterruptible(rq);
6910 BUG_ON(rq->nr_running != 0);
6913 * No need to migrate the tasks: it was best-effort if
6914 * they didn't take sched_hotcpu_mutex. Just wake up
6917 spin_lock_irq(&rq->lock);
6918 while (!list_empty(&rq->migration_queue)) {
6919 struct migration_req *req;
6921 req = list_entry(rq->migration_queue.next,
6922 struct migration_req, list);
6923 list_del_init(&req->list);
6924 spin_unlock_irq(&rq->lock);
6925 complete(&req->done);
6926 spin_lock_irq(&rq->lock);
6928 spin_unlock_irq(&rq->lock);
6932 case CPU_DYING_FROZEN:
6933 /* Update our root-domain */
6935 spin_lock_irqsave(&rq->lock, flags);
6937 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
6940 spin_unlock_irqrestore(&rq->lock, flags);
6947 /* Register at highest priority so that task migration (migrate_all_tasks)
6948 * happens before everything else.
6950 static struct notifier_block __cpuinitdata migration_notifier = {
6951 .notifier_call = migration_call,
6955 static int __init migration_init(void)
6957 void *cpu = (void *)(long)smp_processor_id();
6960 /* Start one for the boot CPU: */
6961 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
6962 BUG_ON(err == NOTIFY_BAD);
6963 migration_call(&migration_notifier, CPU_ONLINE, cpu);
6964 register_cpu_notifier(&migration_notifier);
6968 early_initcall(migration_init);
6973 #ifdef CONFIG_SCHED_DEBUG
6975 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
6976 struct cpumask *groupmask)
6978 struct sched_group *group = sd->groups;
6981 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
6982 cpumask_clear(groupmask);
6984 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
6986 if (!(sd->flags & SD_LOAD_BALANCE)) {
6987 printk("does not load-balance\n");
6989 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
6994 printk(KERN_CONT "span %s level %s\n", str, sd->name);
6996 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
6997 printk(KERN_ERR "ERROR: domain->span does not contain "
7000 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
7001 printk(KERN_ERR "ERROR: domain->groups does not contain"
7005 printk(KERN_DEBUG "%*s groups:", level + 1, "");
7009 printk(KERN_ERR "ERROR: group is NULL\n");
7013 if (!group->__cpu_power) {
7014 printk(KERN_CONT "\n");
7015 printk(KERN_ERR "ERROR: domain->cpu_power not "
7020 if (!cpumask_weight(sched_group_cpus(group))) {
7021 printk(KERN_CONT "\n");
7022 printk(KERN_ERR "ERROR: empty group\n");
7026 if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
7027 printk(KERN_CONT "\n");
7028 printk(KERN_ERR "ERROR: repeated CPUs\n");
7032 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
7034 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
7035 printk(KERN_CONT " %s", str);
7037 group = group->next;
7038 } while (group != sd->groups);
7039 printk(KERN_CONT "\n");
7041 if (!cpumask_equal(sched_domain_span(sd), groupmask))
7042 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
7045 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
7046 printk(KERN_ERR "ERROR: parent span is not a superset "
7047 "of domain->span\n");
7051 static void sched_domain_debug(struct sched_domain *sd, int cpu)
7053 cpumask_var_t groupmask;
7057 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
7061 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
7063 if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) {
7064 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
7069 if (sched_domain_debug_one(sd, cpu, level, groupmask))
7076 free_cpumask_var(groupmask);
7078 #else /* !CONFIG_SCHED_DEBUG */
7079 # define sched_domain_debug(sd, cpu) do { } while (0)
7080 #endif /* CONFIG_SCHED_DEBUG */
7082 static int sd_degenerate(struct sched_domain *sd)
7084 if (cpumask_weight(sched_domain_span(sd)) == 1)
7087 /* Following flags need at least 2 groups */
7088 if (sd->flags & (SD_LOAD_BALANCE |
7089 SD_BALANCE_NEWIDLE |
7093 SD_SHARE_PKG_RESOURCES)) {
7094 if (sd->groups != sd->groups->next)
7098 /* Following flags don't use groups */
7099 if (sd->flags & (SD_WAKE_IDLE |
7108 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
7110 unsigned long cflags = sd->flags, pflags = parent->flags;
7112 if (sd_degenerate(parent))
7115 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
7118 /* Does parent contain flags not in child? */
7119 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7120 if (cflags & SD_WAKE_AFFINE)
7121 pflags &= ~SD_WAKE_BALANCE;
7122 /* Flags needing groups don't count if only 1 group in parent */
7123 if (parent->groups == parent->groups->next) {
7124 pflags &= ~(SD_LOAD_BALANCE |
7125 SD_BALANCE_NEWIDLE |
7129 SD_SHARE_PKG_RESOURCES);
7130 if (nr_node_ids == 1)
7131 pflags &= ~SD_SERIALIZE;
7133 if (~cflags & pflags)
7139 static void free_rootdomain(struct root_domain *rd)
7141 cpupri_cleanup(&rd->cpupri);
7143 free_cpumask_var(rd->rto_mask);
7144 free_cpumask_var(rd->online);
7145 free_cpumask_var(rd->span);
7149 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
7151 struct root_domain *old_rd = NULL;
7152 unsigned long flags;
7154 spin_lock_irqsave(&rq->lock, flags);
7159 if (cpumask_test_cpu(rq->cpu, old_rd->online))
7162 cpumask_clear_cpu(rq->cpu, old_rd->span);
7165 * If we dont want to free the old_rt yet then
7166 * set old_rd to NULL to skip the freeing later
7169 if (!atomic_dec_and_test(&old_rd->refcount))
7173 atomic_inc(&rd->refcount);
7176 cpumask_set_cpu(rq->cpu, rd->span);
7177 if (cpumask_test_cpu(rq->cpu, cpu_online_mask))
7180 spin_unlock_irqrestore(&rq->lock, flags);
7183 free_rootdomain(old_rd);
7186 static int __init_refok init_rootdomain(struct root_domain *rd, bool bootmem)
7188 memset(rd, 0, sizeof(*rd));
7191 alloc_bootmem_cpumask_var(&def_root_domain.span);
7192 alloc_bootmem_cpumask_var(&def_root_domain.online);
7193 alloc_bootmem_cpumask_var(&def_root_domain.rto_mask);
7194 cpupri_init(&rd->cpupri, true);
7198 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
7200 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
7202 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
7205 if (cpupri_init(&rd->cpupri, false) != 0)
7210 free_cpumask_var(rd->rto_mask);
7212 free_cpumask_var(rd->online);
7214 free_cpumask_var(rd->span);
7219 static void init_defrootdomain(void)
7221 init_rootdomain(&def_root_domain, true);
7223 atomic_set(&def_root_domain.refcount, 1);
7226 static struct root_domain *alloc_rootdomain(void)
7228 struct root_domain *rd;
7230 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
7234 if (init_rootdomain(rd, false) != 0) {
7243 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7244 * hold the hotplug lock.
7247 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
7249 struct rq *rq = cpu_rq(cpu);
7250 struct sched_domain *tmp;
7252 /* Remove the sched domains which do not contribute to scheduling. */
7253 for (tmp = sd; tmp; ) {
7254 struct sched_domain *parent = tmp->parent;
7258 if (sd_parent_degenerate(tmp, parent)) {
7259 tmp->parent = parent->parent;
7261 parent->parent->child = tmp;
7266 if (sd && sd_degenerate(sd)) {
7272 sched_domain_debug(sd, cpu);
7274 rq_attach_root(rq, rd);
7275 rcu_assign_pointer(rq->sd, sd);
7278 /* cpus with isolated domains */
7279 static cpumask_var_t cpu_isolated_map;
7281 /* Setup the mask of cpus configured for isolated domains */
7282 static int __init isolated_cpu_setup(char *str)
7284 cpulist_parse(str, cpu_isolated_map);
7288 __setup("isolcpus=", isolated_cpu_setup);
7291 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7292 * to a function which identifies what group(along with sched group) a CPU
7293 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7294 * (due to the fact that we keep track of groups covered with a struct cpumask).
7296 * init_sched_build_groups will build a circular linked list of the groups
7297 * covered by the given span, and will set each group's ->cpumask correctly,
7298 * and ->cpu_power to 0.
7301 init_sched_build_groups(const struct cpumask *span,
7302 const struct cpumask *cpu_map,
7303 int (*group_fn)(int cpu, const struct cpumask *cpu_map,
7304 struct sched_group **sg,
7305 struct cpumask *tmpmask),
7306 struct cpumask *covered, struct cpumask *tmpmask)
7308 struct sched_group *first = NULL, *last = NULL;
7311 cpumask_clear(covered);
7313 for_each_cpu(i, span) {
7314 struct sched_group *sg;
7315 int group = group_fn(i, cpu_map, &sg, tmpmask);
7318 if (cpumask_test_cpu(i, covered))
7321 cpumask_clear(sched_group_cpus(sg));
7322 sg->__cpu_power = 0;
7324 for_each_cpu(j, span) {
7325 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
7328 cpumask_set_cpu(j, covered);
7329 cpumask_set_cpu(j, sched_group_cpus(sg));
7340 #define SD_NODES_PER_DOMAIN 16
7345 * find_next_best_node - find the next node to include in a sched_domain
7346 * @node: node whose sched_domain we're building
7347 * @used_nodes: nodes already in the sched_domain
7349 * Find the next node to include in a given scheduling domain. Simply
7350 * finds the closest node not already in the @used_nodes map.
7352 * Should use nodemask_t.
7354 static int find_next_best_node(int node, nodemask_t *used_nodes)
7356 int i, n, val, min_val, best_node = 0;
7360 for (i = 0; i < nr_node_ids; i++) {
7361 /* Start at @node */
7362 n = (node + i) % nr_node_ids;
7364 if (!nr_cpus_node(n))
7367 /* Skip already used nodes */
7368 if (node_isset(n, *used_nodes))
7371 /* Simple min distance search */
7372 val = node_distance(node, n);
7374 if (val < min_val) {
7380 node_set(best_node, *used_nodes);
7385 * sched_domain_node_span - get a cpumask for a node's sched_domain
7386 * @node: node whose cpumask we're constructing
7387 * @span: resulting cpumask
7389 * Given a node, construct a good cpumask for its sched_domain to span. It
7390 * should be one that prevents unnecessary balancing, but also spreads tasks
7393 static void sched_domain_node_span(int node, struct cpumask *span)
7395 nodemask_t used_nodes;
7398 cpumask_clear(span);
7399 nodes_clear(used_nodes);
7401 cpumask_or(span, span, cpumask_of_node(node));
7402 node_set(node, used_nodes);
7404 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
7405 int next_node = find_next_best_node(node, &used_nodes);
7407 cpumask_or(span, span, cpumask_of_node(next_node));
7410 #endif /* CONFIG_NUMA */
7412 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
7415 * The cpus mask in sched_group and sched_domain hangs off the end.
7416 * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
7417 * for nr_cpu_ids < CONFIG_NR_CPUS.
7419 struct static_sched_group {
7420 struct sched_group sg;
7421 DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
7424 struct static_sched_domain {
7425 struct sched_domain sd;
7426 DECLARE_BITMAP(span, CONFIG_NR_CPUS);
7430 * SMT sched-domains:
7432 #ifdef CONFIG_SCHED_SMT
7433 static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
7434 static DEFINE_PER_CPU(struct static_sched_group, sched_group_cpus);
7437 cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map,
7438 struct sched_group **sg, struct cpumask *unused)
7441 *sg = &per_cpu(sched_group_cpus, cpu).sg;
7444 #endif /* CONFIG_SCHED_SMT */
7447 * multi-core sched-domains:
7449 #ifdef CONFIG_SCHED_MC
7450 static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
7451 static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
7452 #endif /* CONFIG_SCHED_MC */
7454 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7456 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
7457 struct sched_group **sg, struct cpumask *mask)
7461 cpumask_and(mask, &per_cpu(cpu_sibling_map, cpu), cpu_map);
7462 group = cpumask_first(mask);
7464 *sg = &per_cpu(sched_group_core, group).sg;
7467 #elif defined(CONFIG_SCHED_MC)
7469 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
7470 struct sched_group **sg, struct cpumask *unused)
7473 *sg = &per_cpu(sched_group_core, cpu).sg;
7478 static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
7479 static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
7482 cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
7483 struct sched_group **sg, struct cpumask *mask)
7486 #ifdef CONFIG_SCHED_MC
7487 cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
7488 group = cpumask_first(mask);
7489 #elif defined(CONFIG_SCHED_SMT)
7490 cpumask_and(mask, &per_cpu(cpu_sibling_map, cpu), cpu_map);
7491 group = cpumask_first(mask);
7496 *sg = &per_cpu(sched_group_phys, group).sg;
7502 * The init_sched_build_groups can't handle what we want to do with node
7503 * groups, so roll our own. Now each node has its own list of groups which
7504 * gets dynamically allocated.
7506 static DEFINE_PER_CPU(struct static_sched_domain, node_domains);
7507 static struct sched_group ***sched_group_nodes_bycpu;
7509 static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
7510 static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
7512 static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
7513 struct sched_group **sg,
7514 struct cpumask *nodemask)
7518 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map);
7519 group = cpumask_first(nodemask);
7522 *sg = &per_cpu(sched_group_allnodes, group).sg;
7526 static void init_numa_sched_groups_power(struct sched_group *group_head)
7528 struct sched_group *sg = group_head;
7534 for_each_cpu(j, sched_group_cpus(sg)) {
7535 struct sched_domain *sd;
7537 sd = &per_cpu(phys_domains, j).sd;
7538 if (j != cpumask_first(sched_group_cpus(sd->groups))) {
7540 * Only add "power" once for each
7546 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
7549 } while (sg != group_head);
7551 #endif /* CONFIG_NUMA */
7554 /* Free memory allocated for various sched_group structures */
7555 static void free_sched_groups(const struct cpumask *cpu_map,
7556 struct cpumask *nodemask)
7560 for_each_cpu(cpu, cpu_map) {
7561 struct sched_group **sched_group_nodes
7562 = sched_group_nodes_bycpu[cpu];
7564 if (!sched_group_nodes)
7567 for (i = 0; i < nr_node_ids; i++) {
7568 struct sched_group *oldsg, *sg = sched_group_nodes[i];
7570 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
7571 if (cpumask_empty(nodemask))
7581 if (oldsg != sched_group_nodes[i])
7584 kfree(sched_group_nodes);
7585 sched_group_nodes_bycpu[cpu] = NULL;
7588 #else /* !CONFIG_NUMA */
7589 static void free_sched_groups(const struct cpumask *cpu_map,
7590 struct cpumask *nodemask)
7593 #endif /* CONFIG_NUMA */
7596 * Initialize sched groups cpu_power.
7598 * cpu_power indicates the capacity of sched group, which is used while
7599 * distributing the load between different sched groups in a sched domain.
7600 * Typically cpu_power for all the groups in a sched domain will be same unless
7601 * there are asymmetries in the topology. If there are asymmetries, group
7602 * having more cpu_power will pickup more load compared to the group having
7605 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7606 * the maximum number of tasks a group can handle in the presence of other idle
7607 * or lightly loaded groups in the same sched domain.
7609 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
7611 struct sched_domain *child;
7612 struct sched_group *group;
7614 WARN_ON(!sd || !sd->groups);
7616 if (cpu != cpumask_first(sched_group_cpus(sd->groups)))
7621 sd->groups->__cpu_power = 0;
7624 * For perf policy, if the groups in child domain share resources
7625 * (for example cores sharing some portions of the cache hierarchy
7626 * or SMT), then set this domain groups cpu_power such that each group
7627 * can handle only one task, when there are other idle groups in the
7628 * same sched domain.
7630 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
7632 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
7633 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
7638 * add cpu_power of each child group to this groups cpu_power
7640 group = child->groups;
7642 sg_inc_cpu_power(sd->groups, group->__cpu_power);
7643 group = group->next;
7644 } while (group != child->groups);
7648 * Initializers for schedule domains
7649 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7652 #ifdef CONFIG_SCHED_DEBUG
7653 # define SD_INIT_NAME(sd, type) sd->name = #type
7655 # define SD_INIT_NAME(sd, type) do { } while (0)
7658 #define SD_INIT(sd, type) sd_init_##type(sd)
7660 #define SD_INIT_FUNC(type) \
7661 static noinline void sd_init_##type(struct sched_domain *sd) \
7663 memset(sd, 0, sizeof(*sd)); \
7664 *sd = SD_##type##_INIT; \
7665 sd->level = SD_LV_##type; \
7666 SD_INIT_NAME(sd, type); \
7671 SD_INIT_FUNC(ALLNODES)
7674 #ifdef CONFIG_SCHED_SMT
7675 SD_INIT_FUNC(SIBLING)
7677 #ifdef CONFIG_SCHED_MC
7681 static int default_relax_domain_level = -1;
7683 static int __init setup_relax_domain_level(char *str)
7687 val = simple_strtoul(str, NULL, 0);
7688 if (val < SD_LV_MAX)
7689 default_relax_domain_level = val;
7693 __setup("relax_domain_level=", setup_relax_domain_level);
7695 static void set_domain_attribute(struct sched_domain *sd,
7696 struct sched_domain_attr *attr)
7700 if (!attr || attr->relax_domain_level < 0) {
7701 if (default_relax_domain_level < 0)
7704 request = default_relax_domain_level;
7706 request = attr->relax_domain_level;
7707 if (request < sd->level) {
7708 /* turn off idle balance on this domain */
7709 sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
7711 /* turn on idle balance on this domain */
7712 sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
7717 * Build sched domains for a given set of cpus and attach the sched domains
7718 * to the individual cpus
7720 static int __build_sched_domains(const struct cpumask *cpu_map,
7721 struct sched_domain_attr *attr)
7723 int i, err = -ENOMEM;
7724 struct root_domain *rd;
7725 cpumask_var_t nodemask, this_sibling_map, this_core_map, send_covered,
7728 cpumask_var_t domainspan, covered, notcovered;
7729 struct sched_group **sched_group_nodes = NULL;
7730 int sd_allnodes = 0;
7732 if (!alloc_cpumask_var(&domainspan, GFP_KERNEL))
7734 if (!alloc_cpumask_var(&covered, GFP_KERNEL))
7735 goto free_domainspan;
7736 if (!alloc_cpumask_var(¬covered, GFP_KERNEL))
7740 if (!alloc_cpumask_var(&nodemask, GFP_KERNEL))
7741 goto free_notcovered;
7742 if (!alloc_cpumask_var(&this_sibling_map, GFP_KERNEL))
7744 if (!alloc_cpumask_var(&this_core_map, GFP_KERNEL))
7745 goto free_this_sibling_map;
7746 if (!alloc_cpumask_var(&send_covered, GFP_KERNEL))
7747 goto free_this_core_map;
7748 if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
7749 goto free_send_covered;
7753 * Allocate the per-node list of sched groups
7755 sched_group_nodes = kcalloc(nr_node_ids, sizeof(struct sched_group *),
7757 if (!sched_group_nodes) {
7758 printk(KERN_WARNING "Can not alloc sched group node list\n");
7763 rd = alloc_rootdomain();
7765 printk(KERN_WARNING "Cannot alloc root domain\n");
7766 goto free_sched_groups;
7770 sched_group_nodes_bycpu[cpumask_first(cpu_map)] = sched_group_nodes;
7774 * Set up domains for cpus specified by the cpu_map.
7776 for_each_cpu(i, cpu_map) {
7777 struct sched_domain *sd = NULL, *p;
7779 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(i)), cpu_map);
7782 if (cpumask_weight(cpu_map) >
7783 SD_NODES_PER_DOMAIN*cpumask_weight(nodemask)) {
7784 sd = &per_cpu(allnodes_domains, i).sd;
7785 SD_INIT(sd, ALLNODES);
7786 set_domain_attribute(sd, attr);
7787 cpumask_copy(sched_domain_span(sd), cpu_map);
7788 cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
7794 sd = &per_cpu(node_domains, i).sd;
7796 set_domain_attribute(sd, attr);
7797 sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd));
7801 cpumask_and(sched_domain_span(sd),
7802 sched_domain_span(sd), cpu_map);
7806 sd = &per_cpu(phys_domains, i).sd;
7808 set_domain_attribute(sd, attr);
7809 cpumask_copy(sched_domain_span(sd), nodemask);
7813 cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
7815 #ifdef CONFIG_SCHED_MC
7817 sd = &per_cpu(core_domains, i).sd;
7819 set_domain_attribute(sd, attr);
7820 cpumask_and(sched_domain_span(sd), cpu_map,
7821 cpu_coregroup_mask(i));
7824 cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
7827 #ifdef CONFIG_SCHED_SMT
7829 sd = &per_cpu(cpu_domains, i).sd;
7830 SD_INIT(sd, SIBLING);
7831 set_domain_attribute(sd, attr);
7832 cpumask_and(sched_domain_span(sd),
7833 &per_cpu(cpu_sibling_map, i), cpu_map);
7836 cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
7840 #ifdef CONFIG_SCHED_SMT
7841 /* Set up CPU (sibling) groups */
7842 for_each_cpu(i, cpu_map) {
7843 cpumask_and(this_sibling_map,
7844 &per_cpu(cpu_sibling_map, i), cpu_map);
7845 if (i != cpumask_first(this_sibling_map))
7848 init_sched_build_groups(this_sibling_map, cpu_map,
7850 send_covered, tmpmask);
7854 #ifdef CONFIG_SCHED_MC
7855 /* Set up multi-core groups */
7856 for_each_cpu(i, cpu_map) {
7857 cpumask_and(this_core_map, cpu_coregroup_mask(i), cpu_map);
7858 if (i != cpumask_first(this_core_map))
7861 init_sched_build_groups(this_core_map, cpu_map,
7863 send_covered, tmpmask);
7867 /* Set up physical groups */
7868 for (i = 0; i < nr_node_ids; i++) {
7869 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
7870 if (cpumask_empty(nodemask))
7873 init_sched_build_groups(nodemask, cpu_map,
7875 send_covered, tmpmask);
7879 /* Set up node groups */
7881 init_sched_build_groups(cpu_map, cpu_map,
7882 &cpu_to_allnodes_group,
7883 send_covered, tmpmask);
7886 for (i = 0; i < nr_node_ids; i++) {
7887 /* Set up node groups */
7888 struct sched_group *sg, *prev;
7891 cpumask_clear(covered);
7892 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
7893 if (cpumask_empty(nodemask)) {
7894 sched_group_nodes[i] = NULL;
7898 sched_domain_node_span(i, domainspan);
7899 cpumask_and(domainspan, domainspan, cpu_map);
7901 sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
7904 printk(KERN_WARNING "Can not alloc domain group for "
7908 sched_group_nodes[i] = sg;
7909 for_each_cpu(j, nodemask) {
7910 struct sched_domain *sd;
7912 sd = &per_cpu(node_domains, j).sd;
7915 sg->__cpu_power = 0;
7916 cpumask_copy(sched_group_cpus(sg), nodemask);
7918 cpumask_or(covered, covered, nodemask);
7921 for (j = 0; j < nr_node_ids; j++) {
7922 int n = (i + j) % nr_node_ids;
7924 cpumask_complement(notcovered, covered);
7925 cpumask_and(tmpmask, notcovered, cpu_map);
7926 cpumask_and(tmpmask, tmpmask, domainspan);
7927 if (cpumask_empty(tmpmask))
7930 cpumask_and(tmpmask, tmpmask, cpumask_of_node(n));
7931 if (cpumask_empty(tmpmask))
7934 sg = kmalloc_node(sizeof(struct sched_group) +
7939 "Can not alloc domain group for node %d\n", j);
7942 sg->__cpu_power = 0;
7943 cpumask_copy(sched_group_cpus(sg), tmpmask);
7944 sg->next = prev->next;
7945 cpumask_or(covered, covered, tmpmask);
7952 /* Calculate CPU power for physical packages and nodes */
7953 #ifdef CONFIG_SCHED_SMT
7954 for_each_cpu(i, cpu_map) {
7955 struct sched_domain *sd = &per_cpu(cpu_domains, i).sd;
7957 init_sched_groups_power(i, sd);
7960 #ifdef CONFIG_SCHED_MC
7961 for_each_cpu(i, cpu_map) {
7962 struct sched_domain *sd = &per_cpu(core_domains, i).sd;
7964 init_sched_groups_power(i, sd);
7968 for_each_cpu(i, cpu_map) {
7969 struct sched_domain *sd = &per_cpu(phys_domains, i).sd;
7971 init_sched_groups_power(i, sd);
7975 for (i = 0; i < nr_node_ids; i++)
7976 init_numa_sched_groups_power(sched_group_nodes[i]);
7979 struct sched_group *sg;
7981 cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg,
7983 init_numa_sched_groups_power(sg);
7987 /* Attach the domains */
7988 for_each_cpu(i, cpu_map) {
7989 struct sched_domain *sd;
7990 #ifdef CONFIG_SCHED_SMT
7991 sd = &per_cpu(cpu_domains, i).sd;
7992 #elif defined(CONFIG_SCHED_MC)
7993 sd = &per_cpu(core_domains, i).sd;
7995 sd = &per_cpu(phys_domains, i).sd;
7997 cpu_attach_domain(sd, rd, i);
8003 free_cpumask_var(tmpmask);
8005 free_cpumask_var(send_covered);
8007 free_cpumask_var(this_core_map);
8008 free_this_sibling_map:
8009 free_cpumask_var(this_sibling_map);
8011 free_cpumask_var(nodemask);
8014 free_cpumask_var(notcovered);
8016 free_cpumask_var(covered);
8018 free_cpumask_var(domainspan);
8025 kfree(sched_group_nodes);
8031 free_sched_groups(cpu_map, tmpmask);
8032 free_rootdomain(rd);
8037 static int build_sched_domains(const struct cpumask *cpu_map)
8039 return __build_sched_domains(cpu_map, NULL);
8042 static struct cpumask *doms_cur; /* current sched domains */
8043 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
8044 static struct sched_domain_attr *dattr_cur;
8045 /* attribues of custom domains in 'doms_cur' */
8048 * Special case: If a kmalloc of a doms_cur partition (array of
8049 * cpumask) fails, then fallback to a single sched domain,
8050 * as determined by the single cpumask fallback_doms.
8052 static cpumask_var_t fallback_doms;
8055 * arch_update_cpu_topology lets virtualized architectures update the
8056 * cpu core maps. It is supposed to return 1 if the topology changed
8057 * or 0 if it stayed the same.
8059 int __attribute__((weak)) arch_update_cpu_topology(void)
8065 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8066 * For now this just excludes isolated cpus, but could be used to
8067 * exclude other special cases in the future.
8069 static int arch_init_sched_domains(const struct cpumask *cpu_map)
8073 arch_update_cpu_topology();
8075 doms_cur = kmalloc(cpumask_size(), GFP_KERNEL);
8077 doms_cur = fallback_doms;
8078 cpumask_andnot(doms_cur, cpu_map, cpu_isolated_map);
8080 err = build_sched_domains(doms_cur);
8081 register_sched_domain_sysctl();
8086 static void arch_destroy_sched_domains(const struct cpumask *cpu_map,
8087 struct cpumask *tmpmask)
8089 free_sched_groups(cpu_map, tmpmask);
8093 * Detach sched domains from a group of cpus specified in cpu_map
8094 * These cpus will now be attached to the NULL domain
8096 static void detach_destroy_domains(const struct cpumask *cpu_map)
8098 /* Save because hotplug lock held. */
8099 static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS);
8102 for_each_cpu(i, cpu_map)
8103 cpu_attach_domain(NULL, &def_root_domain, i);
8104 synchronize_sched();
8105 arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask));
8108 /* handle null as "default" */
8109 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
8110 struct sched_domain_attr *new, int idx_new)
8112 struct sched_domain_attr tmp;
8119 return !memcmp(cur ? (cur + idx_cur) : &tmp,
8120 new ? (new + idx_new) : &tmp,
8121 sizeof(struct sched_domain_attr));
8125 * Partition sched domains as specified by the 'ndoms_new'
8126 * cpumasks in the array doms_new[] of cpumasks. This compares
8127 * doms_new[] to the current sched domain partitioning, doms_cur[].
8128 * It destroys each deleted domain and builds each new domain.
8130 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8131 * The masks don't intersect (don't overlap.) We should setup one
8132 * sched domain for each mask. CPUs not in any of the cpumasks will
8133 * not be load balanced. If the same cpumask appears both in the
8134 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8137 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8138 * ownership of it and will kfree it when done with it. If the caller
8139 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8140 * ndoms_new == 1, and partition_sched_domains() will fallback to
8141 * the single partition 'fallback_doms', it also forces the domains
8144 * If doms_new == NULL it will be replaced with cpu_online_mask.
8145 * ndoms_new == 0 is a special case for destroying existing domains,
8146 * and it will not create the default domain.
8148 * Call with hotplug lock held
8150 /* FIXME: Change to struct cpumask *doms_new[] */
8151 void partition_sched_domains(int ndoms_new, struct cpumask *doms_new,
8152 struct sched_domain_attr *dattr_new)
8157 mutex_lock(&sched_domains_mutex);
8159 /* always unregister in case we don't destroy any domains */
8160 unregister_sched_domain_sysctl();
8162 /* Let architecture update cpu core mappings. */
8163 new_topology = arch_update_cpu_topology();
8165 n = doms_new ? ndoms_new : 0;
8167 /* Destroy deleted domains */
8168 for (i = 0; i < ndoms_cur; i++) {
8169 for (j = 0; j < n && !new_topology; j++) {
8170 if (cpumask_equal(&doms_cur[i], &doms_new[j])
8171 && dattrs_equal(dattr_cur, i, dattr_new, j))
8174 /* no match - a current sched domain not in new doms_new[] */
8175 detach_destroy_domains(doms_cur + i);
8180 if (doms_new == NULL) {
8182 doms_new = fallback_doms;
8183 cpumask_andnot(&doms_new[0], cpu_online_mask, cpu_isolated_map);
8184 WARN_ON_ONCE(dattr_new);
8187 /* Build new domains */
8188 for (i = 0; i < ndoms_new; i++) {
8189 for (j = 0; j < ndoms_cur && !new_topology; j++) {
8190 if (cpumask_equal(&doms_new[i], &doms_cur[j])
8191 && dattrs_equal(dattr_new, i, dattr_cur, j))
8194 /* no match - add a new doms_new */
8195 __build_sched_domains(doms_new + i,
8196 dattr_new ? dattr_new + i : NULL);
8201 /* Remember the new sched domains */
8202 if (doms_cur != fallback_doms)
8204 kfree(dattr_cur); /* kfree(NULL) is safe */
8205 doms_cur = doms_new;
8206 dattr_cur = dattr_new;
8207 ndoms_cur = ndoms_new;
8209 register_sched_domain_sysctl();
8211 mutex_unlock(&sched_domains_mutex);
8214 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8215 static void arch_reinit_sched_domains(void)
8219 /* Destroy domains first to force the rebuild */
8220 partition_sched_domains(0, NULL, NULL);
8222 rebuild_sched_domains();
8226 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
8228 unsigned int level = 0;
8230 if (sscanf(buf, "%u", &level) != 1)
8234 * level is always be positive so don't check for
8235 * level < POWERSAVINGS_BALANCE_NONE which is 0
8236 * What happens on 0 or 1 byte write,
8237 * need to check for count as well?
8240 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
8244 sched_smt_power_savings = level;
8246 sched_mc_power_savings = level;
8248 arch_reinit_sched_domains();
8253 #ifdef CONFIG_SCHED_MC
8254 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
8257 return sprintf(page, "%u\n", sched_mc_power_savings);
8259 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
8260 const char *buf, size_t count)
8262 return sched_power_savings_store(buf, count, 0);
8264 static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
8265 sched_mc_power_savings_show,
8266 sched_mc_power_savings_store);
8269 #ifdef CONFIG_SCHED_SMT
8270 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
8273 return sprintf(page, "%u\n", sched_smt_power_savings);
8275 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
8276 const char *buf, size_t count)
8278 return sched_power_savings_store(buf, count, 1);
8280 static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
8281 sched_smt_power_savings_show,
8282 sched_smt_power_savings_store);
8285 int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
8289 #ifdef CONFIG_SCHED_SMT
8291 err = sysfs_create_file(&cls->kset.kobj,
8292 &attr_sched_smt_power_savings.attr);
8294 #ifdef CONFIG_SCHED_MC
8295 if (!err && mc_capable())
8296 err = sysfs_create_file(&cls->kset.kobj,
8297 &attr_sched_mc_power_savings.attr);
8301 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
8303 #ifndef CONFIG_CPUSETS
8305 * Add online and remove offline CPUs from the scheduler domains.
8306 * When cpusets are enabled they take over this function.
8308 static int update_sched_domains(struct notifier_block *nfb,
8309 unsigned long action, void *hcpu)
8313 case CPU_ONLINE_FROZEN:
8315 case CPU_DEAD_FROZEN:
8316 partition_sched_domains(1, NULL, NULL);
8325 static int update_runtime(struct notifier_block *nfb,
8326 unsigned long action, void *hcpu)
8328 int cpu = (int)(long)hcpu;
8331 case CPU_DOWN_PREPARE:
8332 case CPU_DOWN_PREPARE_FROZEN:
8333 disable_runtime(cpu_rq(cpu));
8336 case CPU_DOWN_FAILED:
8337 case CPU_DOWN_FAILED_FROZEN:
8339 case CPU_ONLINE_FROZEN:
8340 enable_runtime(cpu_rq(cpu));
8348 void __init sched_init_smp(void)
8350 cpumask_var_t non_isolated_cpus;
8352 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
8354 #if defined(CONFIG_NUMA)
8355 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
8357 BUG_ON(sched_group_nodes_bycpu == NULL);
8360 mutex_lock(&sched_domains_mutex);
8361 arch_init_sched_domains(cpu_online_mask);
8362 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
8363 if (cpumask_empty(non_isolated_cpus))
8364 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
8365 mutex_unlock(&sched_domains_mutex);
8368 #ifndef CONFIG_CPUSETS
8369 /* XXX: Theoretical race here - CPU may be hotplugged now */
8370 hotcpu_notifier(update_sched_domains, 0);
8373 /* RT runtime code needs to handle some hotplug events */
8374 hotcpu_notifier(update_runtime, 0);
8378 /* Move init over to a non-isolated CPU */
8379 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
8381 sched_init_granularity();
8382 free_cpumask_var(non_isolated_cpus);
8384 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
8385 init_sched_rt_class();
8388 void __init sched_init_smp(void)
8390 sched_init_granularity();
8392 #endif /* CONFIG_SMP */
8394 int in_sched_functions(unsigned long addr)
8396 return in_lock_functions(addr) ||
8397 (addr >= (unsigned long)__sched_text_start
8398 && addr < (unsigned long)__sched_text_end);
8401 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
8403 cfs_rq->tasks_timeline = RB_ROOT;
8404 INIT_LIST_HEAD(&cfs_rq->tasks);
8405 #ifdef CONFIG_FAIR_GROUP_SCHED
8408 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
8411 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
8413 struct rt_prio_array *array;
8416 array = &rt_rq->active;
8417 for (i = 0; i < MAX_RT_PRIO; i++) {
8418 INIT_LIST_HEAD(array->queue + i);
8419 __clear_bit(i, array->bitmap);
8421 /* delimiter for bitsearch: */
8422 __set_bit(MAX_RT_PRIO, array->bitmap);
8424 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8425 rt_rq->highest_prio.curr = MAX_RT_PRIO;
8427 rt_rq->highest_prio.next = MAX_RT_PRIO;
8431 rt_rq->rt_nr_migratory = 0;
8432 rt_rq->overloaded = 0;
8433 plist_head_init(&rq->rt.pushable_tasks, &rq->lock);
8437 rt_rq->rt_throttled = 0;
8438 rt_rq->rt_runtime = 0;
8439 spin_lock_init(&rt_rq->rt_runtime_lock);
8441 #ifdef CONFIG_RT_GROUP_SCHED
8442 rt_rq->rt_nr_boosted = 0;
8447 #ifdef CONFIG_FAIR_GROUP_SCHED
8448 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
8449 struct sched_entity *se, int cpu, int add,
8450 struct sched_entity *parent)
8452 struct rq *rq = cpu_rq(cpu);
8453 tg->cfs_rq[cpu] = cfs_rq;
8454 init_cfs_rq(cfs_rq, rq);
8457 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
8460 /* se could be NULL for init_task_group */
8465 se->cfs_rq = &rq->cfs;
8467 se->cfs_rq = parent->my_q;
8470 se->load.weight = tg->shares;
8471 se->load.inv_weight = 0;
8472 se->parent = parent;
8476 #ifdef CONFIG_RT_GROUP_SCHED
8477 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
8478 struct sched_rt_entity *rt_se, int cpu, int add,
8479 struct sched_rt_entity *parent)
8481 struct rq *rq = cpu_rq(cpu);
8483 tg->rt_rq[cpu] = rt_rq;
8484 init_rt_rq(rt_rq, rq);
8486 rt_rq->rt_se = rt_se;
8487 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
8489 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
8491 tg->rt_se[cpu] = rt_se;
8496 rt_se->rt_rq = &rq->rt;
8498 rt_se->rt_rq = parent->my_q;
8500 rt_se->my_q = rt_rq;
8501 rt_se->parent = parent;
8502 INIT_LIST_HEAD(&rt_se->run_list);
8506 void __init sched_init(void)
8509 unsigned long alloc_size = 0, ptr;
8511 #ifdef CONFIG_FAIR_GROUP_SCHED
8512 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8514 #ifdef CONFIG_RT_GROUP_SCHED
8515 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8517 #ifdef CONFIG_USER_SCHED
8521 * As sched_init() is called before page_alloc is setup,
8522 * we use alloc_bootmem().
8525 ptr = (unsigned long)alloc_bootmem(alloc_size);
8527 #ifdef CONFIG_FAIR_GROUP_SCHED
8528 init_task_group.se = (struct sched_entity **)ptr;
8529 ptr += nr_cpu_ids * sizeof(void **);
8531 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
8532 ptr += nr_cpu_ids * sizeof(void **);
8534 #ifdef CONFIG_USER_SCHED
8535 root_task_group.se = (struct sched_entity **)ptr;
8536 ptr += nr_cpu_ids * sizeof(void **);
8538 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
8539 ptr += nr_cpu_ids * sizeof(void **);
8540 #endif /* CONFIG_USER_SCHED */
8541 #endif /* CONFIG_FAIR_GROUP_SCHED */
8542 #ifdef CONFIG_RT_GROUP_SCHED
8543 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
8544 ptr += nr_cpu_ids * sizeof(void **);
8546 init_task_group.rt_rq = (struct rt_rq **)ptr;
8547 ptr += nr_cpu_ids * sizeof(void **);
8549 #ifdef CONFIG_USER_SCHED
8550 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
8551 ptr += nr_cpu_ids * sizeof(void **);
8553 root_task_group.rt_rq = (struct rt_rq **)ptr;
8554 ptr += nr_cpu_ids * sizeof(void **);
8555 #endif /* CONFIG_USER_SCHED */
8556 #endif /* CONFIG_RT_GROUP_SCHED */
8560 init_defrootdomain();
8563 init_rt_bandwidth(&def_rt_bandwidth,
8564 global_rt_period(), global_rt_runtime());
8566 #ifdef CONFIG_RT_GROUP_SCHED
8567 init_rt_bandwidth(&init_task_group.rt_bandwidth,
8568 global_rt_period(), global_rt_runtime());
8569 #ifdef CONFIG_USER_SCHED
8570 init_rt_bandwidth(&root_task_group.rt_bandwidth,
8571 global_rt_period(), RUNTIME_INF);
8572 #endif /* CONFIG_USER_SCHED */
8573 #endif /* CONFIG_RT_GROUP_SCHED */
8575 #ifdef CONFIG_GROUP_SCHED
8576 list_add(&init_task_group.list, &task_groups);
8577 INIT_LIST_HEAD(&init_task_group.children);
8579 #ifdef CONFIG_USER_SCHED
8580 INIT_LIST_HEAD(&root_task_group.children);
8581 init_task_group.parent = &root_task_group;
8582 list_add(&init_task_group.siblings, &root_task_group.children);
8583 #endif /* CONFIG_USER_SCHED */
8584 #endif /* CONFIG_GROUP_SCHED */
8586 for_each_possible_cpu(i) {
8590 spin_lock_init(&rq->lock);
8592 init_cfs_rq(&rq->cfs, rq);
8593 init_rt_rq(&rq->rt, rq);
8594 #ifdef CONFIG_FAIR_GROUP_SCHED
8595 init_task_group.shares = init_task_group_load;
8596 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
8597 #ifdef CONFIG_CGROUP_SCHED
8599 * How much cpu bandwidth does init_task_group get?
8601 * In case of task-groups formed thr' the cgroup filesystem, it
8602 * gets 100% of the cpu resources in the system. This overall
8603 * system cpu resource is divided among the tasks of
8604 * init_task_group and its child task-groups in a fair manner,
8605 * based on each entity's (task or task-group's) weight
8606 * (se->load.weight).
8608 * In other words, if init_task_group has 10 tasks of weight
8609 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8610 * then A0's share of the cpu resource is:
8612 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8614 * We achieve this by letting init_task_group's tasks sit
8615 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8617 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
8618 #elif defined CONFIG_USER_SCHED
8619 root_task_group.shares = NICE_0_LOAD;
8620 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
8622 * In case of task-groups formed thr' the user id of tasks,
8623 * init_task_group represents tasks belonging to root user.
8624 * Hence it forms a sibling of all subsequent groups formed.
8625 * In this case, init_task_group gets only a fraction of overall
8626 * system cpu resource, based on the weight assigned to root
8627 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8628 * by letting tasks of init_task_group sit in a separate cfs_rq
8629 * (init_cfs_rq) and having one entity represent this group of
8630 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8632 init_tg_cfs_entry(&init_task_group,
8633 &per_cpu(init_cfs_rq, i),
8634 &per_cpu(init_sched_entity, i), i, 1,
8635 root_task_group.se[i]);
8638 #endif /* CONFIG_FAIR_GROUP_SCHED */
8640 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
8641 #ifdef CONFIG_RT_GROUP_SCHED
8642 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
8643 #ifdef CONFIG_CGROUP_SCHED
8644 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
8645 #elif defined CONFIG_USER_SCHED
8646 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
8647 init_tg_rt_entry(&init_task_group,
8648 &per_cpu(init_rt_rq, i),
8649 &per_cpu(init_sched_rt_entity, i), i, 1,
8650 root_task_group.rt_se[i]);
8654 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
8655 rq->cpu_load[j] = 0;
8659 rq->active_balance = 0;
8660 rq->next_balance = jiffies;
8664 rq->migration_thread = NULL;
8665 INIT_LIST_HEAD(&rq->migration_queue);
8666 rq_attach_root(rq, &def_root_domain);
8669 atomic_set(&rq->nr_iowait, 0);
8672 set_load_weight(&init_task);
8674 #ifdef CONFIG_PREEMPT_NOTIFIERS
8675 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
8679 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
8682 #ifdef CONFIG_RT_MUTEXES
8683 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
8687 * The boot idle thread does lazy MMU switching as well:
8689 atomic_inc(&init_mm.mm_count);
8690 enter_lazy_tlb(&init_mm, current);
8693 * Make us the idle thread. Technically, schedule() should not be
8694 * called from this thread, however somewhere below it might be,
8695 * but because we are the idle thread, we just pick up running again
8696 * when this runqueue becomes "idle".
8698 init_idle(current, smp_processor_id());
8700 * During early bootup we pretend to be a normal task:
8702 current->sched_class = &fair_sched_class;
8704 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
8705 alloc_bootmem_cpumask_var(&nohz_cpu_mask);
8708 alloc_bootmem_cpumask_var(&nohz.cpu_mask);
8710 alloc_bootmem_cpumask_var(&cpu_isolated_map);
8713 scheduler_running = 1;
8716 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
8717 void __might_sleep(char *file, int line)
8720 static unsigned long prev_jiffy; /* ratelimiting */
8722 if ((!in_atomic() && !irqs_disabled()) ||
8723 system_state != SYSTEM_RUNNING || oops_in_progress)
8725 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
8727 prev_jiffy = jiffies;
8730 "BUG: sleeping function called from invalid context at %s:%d\n",
8733 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
8734 in_atomic(), irqs_disabled(),
8735 current->pid, current->comm);
8737 debug_show_held_locks(current);
8738 if (irqs_disabled())
8739 print_irqtrace_events(current);
8743 EXPORT_SYMBOL(__might_sleep);
8746 #ifdef CONFIG_MAGIC_SYSRQ
8747 static void normalize_task(struct rq *rq, struct task_struct *p)
8751 update_rq_clock(rq);
8752 on_rq = p->se.on_rq;
8754 deactivate_task(rq, p, 0);
8755 __setscheduler(rq, p, SCHED_NORMAL, 0);
8757 activate_task(rq, p, 0);
8758 resched_task(rq->curr);
8762 void normalize_rt_tasks(void)
8764 struct task_struct *g, *p;
8765 unsigned long flags;
8768 read_lock_irqsave(&tasklist_lock, flags);
8769 do_each_thread(g, p) {
8771 * Only normalize user tasks:
8776 p->se.exec_start = 0;
8777 #ifdef CONFIG_SCHEDSTATS
8778 p->se.wait_start = 0;
8779 p->se.sleep_start = 0;
8780 p->se.block_start = 0;
8785 * Renice negative nice level userspace
8788 if (TASK_NICE(p) < 0 && p->mm)
8789 set_user_nice(p, 0);
8793 spin_lock(&p->pi_lock);
8794 rq = __task_rq_lock(p);
8796 normalize_task(rq, p);
8798 __task_rq_unlock(rq);
8799 spin_unlock(&p->pi_lock);
8800 } while_each_thread(g, p);
8802 read_unlock_irqrestore(&tasklist_lock, flags);
8805 #endif /* CONFIG_MAGIC_SYSRQ */
8809 * These functions are only useful for the IA64 MCA handling.
8811 * They can only be called when the whole system has been
8812 * stopped - every CPU needs to be quiescent, and no scheduling
8813 * activity can take place. Using them for anything else would
8814 * be a serious bug, and as a result, they aren't even visible
8815 * under any other configuration.
8819 * curr_task - return the current task for a given cpu.
8820 * @cpu: the processor in question.
8822 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8824 struct task_struct *curr_task(int cpu)
8826 return cpu_curr(cpu);
8830 * set_curr_task - set the current task for a given cpu.
8831 * @cpu: the processor in question.
8832 * @p: the task pointer to set.
8834 * Description: This function must only be used when non-maskable interrupts
8835 * are serviced on a separate stack. It allows the architecture to switch the
8836 * notion of the current task on a cpu in a non-blocking manner. This function
8837 * must be called with all CPU's synchronized, and interrupts disabled, the
8838 * and caller must save the original value of the current task (see
8839 * curr_task() above) and restore that value before reenabling interrupts and
8840 * re-starting the system.
8842 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8844 void set_curr_task(int cpu, struct task_struct *p)
8851 #ifdef CONFIG_FAIR_GROUP_SCHED
8852 static void free_fair_sched_group(struct task_group *tg)
8856 for_each_possible_cpu(i) {
8858 kfree(tg->cfs_rq[i]);
8868 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8870 struct cfs_rq *cfs_rq;
8871 struct sched_entity *se;
8875 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
8878 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
8882 tg->shares = NICE_0_LOAD;
8884 for_each_possible_cpu(i) {
8887 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
8888 GFP_KERNEL, cpu_to_node(i));
8892 se = kzalloc_node(sizeof(struct sched_entity),
8893 GFP_KERNEL, cpu_to_node(i));
8897 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
8906 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8908 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
8909 &cpu_rq(cpu)->leaf_cfs_rq_list);
8912 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8914 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
8916 #else /* !CONFG_FAIR_GROUP_SCHED */
8917 static inline void free_fair_sched_group(struct task_group *tg)
8922 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8927 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8931 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8934 #endif /* CONFIG_FAIR_GROUP_SCHED */
8936 #ifdef CONFIG_RT_GROUP_SCHED
8937 static void free_rt_sched_group(struct task_group *tg)
8941 destroy_rt_bandwidth(&tg->rt_bandwidth);
8943 for_each_possible_cpu(i) {
8945 kfree(tg->rt_rq[i]);
8947 kfree(tg->rt_se[i]);
8955 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8957 struct rt_rq *rt_rq;
8958 struct sched_rt_entity *rt_se;
8962 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
8965 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
8969 init_rt_bandwidth(&tg->rt_bandwidth,
8970 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
8972 for_each_possible_cpu(i) {
8975 rt_rq = kzalloc_node(sizeof(struct rt_rq),
8976 GFP_KERNEL, cpu_to_node(i));
8980 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
8981 GFP_KERNEL, cpu_to_node(i));
8985 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
8994 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8996 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
8997 &cpu_rq(cpu)->leaf_rt_rq_list);
9000 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
9002 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
9004 #else /* !CONFIG_RT_GROUP_SCHED */
9005 static inline void free_rt_sched_group(struct task_group *tg)
9010 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
9015 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
9019 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
9022 #endif /* CONFIG_RT_GROUP_SCHED */
9024 #ifdef CONFIG_GROUP_SCHED
9025 static void free_sched_group(struct task_group *tg)
9027 free_fair_sched_group(tg);
9028 free_rt_sched_group(tg);
9032 /* allocate runqueue etc for a new task group */
9033 struct task_group *sched_create_group(struct task_group *parent)
9035 struct task_group *tg;
9036 unsigned long flags;
9039 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
9041 return ERR_PTR(-ENOMEM);
9043 if (!alloc_fair_sched_group(tg, parent))
9046 if (!alloc_rt_sched_group(tg, parent))
9049 spin_lock_irqsave(&task_group_lock, flags);
9050 for_each_possible_cpu(i) {
9051 register_fair_sched_group(tg, i);
9052 register_rt_sched_group(tg, i);
9054 list_add_rcu(&tg->list, &task_groups);
9056 WARN_ON(!parent); /* root should already exist */
9058 tg->parent = parent;
9059 INIT_LIST_HEAD(&tg->children);
9060 list_add_rcu(&tg->siblings, &parent->children);
9061 spin_unlock_irqrestore(&task_group_lock, flags);
9066 free_sched_group(tg);
9067 return ERR_PTR(-ENOMEM);
9070 /* rcu callback to free various structures associated with a task group */
9071 static void free_sched_group_rcu(struct rcu_head *rhp)
9073 /* now it should be safe to free those cfs_rqs */
9074 free_sched_group(container_of(rhp, struct task_group, rcu));
9077 /* Destroy runqueue etc associated with a task group */
9078 void sched_destroy_group(struct task_group *tg)
9080 unsigned long flags;
9083 spin_lock_irqsave(&task_group_lock, flags);
9084 for_each_possible_cpu(i) {
9085 unregister_fair_sched_group(tg, i);
9086 unregister_rt_sched_group(tg, i);
9088 list_del_rcu(&tg->list);
9089 list_del_rcu(&tg->siblings);
9090 spin_unlock_irqrestore(&task_group_lock, flags);
9092 /* wait for possible concurrent references to cfs_rqs complete */
9093 call_rcu(&tg->rcu, free_sched_group_rcu);
9096 /* change task's runqueue when it moves between groups.
9097 * The caller of this function should have put the task in its new group
9098 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
9099 * reflect its new group.
9101 void sched_move_task(struct task_struct *tsk)
9104 unsigned long flags;
9107 rq = task_rq_lock(tsk, &flags);
9109 update_rq_clock(rq);
9111 running = task_current(rq, tsk);
9112 on_rq = tsk->se.on_rq;
9115 dequeue_task(rq, tsk, 0);
9116 if (unlikely(running))
9117 tsk->sched_class->put_prev_task(rq, tsk);
9119 set_task_rq(tsk, task_cpu(tsk));
9121 #ifdef CONFIG_FAIR_GROUP_SCHED
9122 if (tsk->sched_class->moved_group)
9123 tsk->sched_class->moved_group(tsk);
9126 if (unlikely(running))
9127 tsk->sched_class->set_curr_task(rq);
9129 enqueue_task(rq, tsk, 0);
9131 task_rq_unlock(rq, &flags);
9133 #endif /* CONFIG_GROUP_SCHED */
9135 #ifdef CONFIG_FAIR_GROUP_SCHED
9136 static void __set_se_shares(struct sched_entity *se, unsigned long shares)
9138 struct cfs_rq *cfs_rq = se->cfs_rq;
9143 dequeue_entity(cfs_rq, se, 0);
9145 se->load.weight = shares;
9146 se->load.inv_weight = 0;
9149 enqueue_entity(cfs_rq, se, 0);
9152 static void set_se_shares(struct sched_entity *se, unsigned long shares)
9154 struct cfs_rq *cfs_rq = se->cfs_rq;
9155 struct rq *rq = cfs_rq->rq;
9156 unsigned long flags;
9158 spin_lock_irqsave(&rq->lock, flags);
9159 __set_se_shares(se, shares);
9160 spin_unlock_irqrestore(&rq->lock, flags);
9163 static DEFINE_MUTEX(shares_mutex);
9165 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
9168 unsigned long flags;
9171 * We can't change the weight of the root cgroup.
9176 if (shares < MIN_SHARES)
9177 shares = MIN_SHARES;
9178 else if (shares > MAX_SHARES)
9179 shares = MAX_SHARES;
9181 mutex_lock(&shares_mutex);
9182 if (tg->shares == shares)
9185 spin_lock_irqsave(&task_group_lock, flags);
9186 for_each_possible_cpu(i)
9187 unregister_fair_sched_group(tg, i);
9188 list_del_rcu(&tg->siblings);
9189 spin_unlock_irqrestore(&task_group_lock, flags);
9191 /* wait for any ongoing reference to this group to finish */
9192 synchronize_sched();
9195 * Now we are free to modify the group's share on each cpu
9196 * w/o tripping rebalance_share or load_balance_fair.
9198 tg->shares = shares;
9199 for_each_possible_cpu(i) {
9203 cfs_rq_set_shares(tg->cfs_rq[i], 0);
9204 set_se_shares(tg->se[i], shares);
9208 * Enable load balance activity on this group, by inserting it back on
9209 * each cpu's rq->leaf_cfs_rq_list.
9211 spin_lock_irqsave(&task_group_lock, flags);
9212 for_each_possible_cpu(i)
9213 register_fair_sched_group(tg, i);
9214 list_add_rcu(&tg->siblings, &tg->parent->children);
9215 spin_unlock_irqrestore(&task_group_lock, flags);
9217 mutex_unlock(&shares_mutex);
9221 unsigned long sched_group_shares(struct task_group *tg)
9227 #ifdef CONFIG_RT_GROUP_SCHED
9229 * Ensure that the real time constraints are schedulable.
9231 static DEFINE_MUTEX(rt_constraints_mutex);
9233 static unsigned long to_ratio(u64 period, u64 runtime)
9235 if (runtime == RUNTIME_INF)
9238 return div64_u64(runtime << 20, period);
9241 /* Must be called with tasklist_lock held */
9242 static inline int tg_has_rt_tasks(struct task_group *tg)
9244 struct task_struct *g, *p;
9246 do_each_thread(g, p) {
9247 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
9249 } while_each_thread(g, p);
9254 struct rt_schedulable_data {
9255 struct task_group *tg;
9260 static int tg_schedulable(struct task_group *tg, void *data)
9262 struct rt_schedulable_data *d = data;
9263 struct task_group *child;
9264 unsigned long total, sum = 0;
9265 u64 period, runtime;
9267 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
9268 runtime = tg->rt_bandwidth.rt_runtime;
9271 period = d->rt_period;
9272 runtime = d->rt_runtime;
9275 #ifdef CONFIG_USER_SCHED
9276 if (tg == &root_task_group) {
9277 period = global_rt_period();
9278 runtime = global_rt_runtime();
9283 * Cannot have more runtime than the period.
9285 if (runtime > period && runtime != RUNTIME_INF)
9289 * Ensure we don't starve existing RT tasks.
9291 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
9294 total = to_ratio(period, runtime);
9297 * Nobody can have more than the global setting allows.
9299 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
9303 * The sum of our children's runtime should not exceed our own.
9305 list_for_each_entry_rcu(child, &tg->children, siblings) {
9306 period = ktime_to_ns(child->rt_bandwidth.rt_period);
9307 runtime = child->rt_bandwidth.rt_runtime;
9309 if (child == d->tg) {
9310 period = d->rt_period;
9311 runtime = d->rt_runtime;
9314 sum += to_ratio(period, runtime);
9323 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
9325 struct rt_schedulable_data data = {
9327 .rt_period = period,
9328 .rt_runtime = runtime,
9331 return walk_tg_tree(tg_schedulable, tg_nop, &data);
9334 static int tg_set_bandwidth(struct task_group *tg,
9335 u64 rt_period, u64 rt_runtime)
9339 mutex_lock(&rt_constraints_mutex);
9340 read_lock(&tasklist_lock);
9341 err = __rt_schedulable(tg, rt_period, rt_runtime);
9345 spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
9346 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
9347 tg->rt_bandwidth.rt_runtime = rt_runtime;
9349 for_each_possible_cpu(i) {
9350 struct rt_rq *rt_rq = tg->rt_rq[i];
9352 spin_lock(&rt_rq->rt_runtime_lock);
9353 rt_rq->rt_runtime = rt_runtime;
9354 spin_unlock(&rt_rq->rt_runtime_lock);
9356 spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
9358 read_unlock(&tasklist_lock);
9359 mutex_unlock(&rt_constraints_mutex);
9364 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
9366 u64 rt_runtime, rt_period;
9368 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
9369 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
9370 if (rt_runtime_us < 0)
9371 rt_runtime = RUNTIME_INF;
9373 return tg_set_bandwidth(tg, rt_period, rt_runtime);
9376 long sched_group_rt_runtime(struct task_group *tg)
9380 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
9383 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
9384 do_div(rt_runtime_us, NSEC_PER_USEC);
9385 return rt_runtime_us;
9388 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
9390 u64 rt_runtime, rt_period;
9392 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
9393 rt_runtime = tg->rt_bandwidth.rt_runtime;
9398 return tg_set_bandwidth(tg, rt_period, rt_runtime);
9401 long sched_group_rt_period(struct task_group *tg)
9405 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
9406 do_div(rt_period_us, NSEC_PER_USEC);
9407 return rt_period_us;
9410 static int sched_rt_global_constraints(void)
9412 u64 runtime, period;
9415 if (sysctl_sched_rt_period <= 0)
9418 runtime = global_rt_runtime();
9419 period = global_rt_period();
9422 * Sanity check on the sysctl variables.
9424 if (runtime > period && runtime != RUNTIME_INF)
9427 mutex_lock(&rt_constraints_mutex);
9428 read_lock(&tasklist_lock);
9429 ret = __rt_schedulable(NULL, 0, 0);
9430 read_unlock(&tasklist_lock);
9431 mutex_unlock(&rt_constraints_mutex);
9436 int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
9438 /* Don't accept realtime tasks when there is no way for them to run */
9439 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
9445 #else /* !CONFIG_RT_GROUP_SCHED */
9446 static int sched_rt_global_constraints(void)
9448 unsigned long flags;
9451 if (sysctl_sched_rt_period <= 0)
9454 spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
9455 for_each_possible_cpu(i) {
9456 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
9458 spin_lock(&rt_rq->rt_runtime_lock);
9459 rt_rq->rt_runtime = global_rt_runtime();
9460 spin_unlock(&rt_rq->rt_runtime_lock);
9462 spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
9466 #endif /* CONFIG_RT_GROUP_SCHED */
9468 int sched_rt_handler(struct ctl_table *table, int write,
9469 struct file *filp, void __user *buffer, size_t *lenp,
9473 int old_period, old_runtime;
9474 static DEFINE_MUTEX(mutex);
9477 old_period = sysctl_sched_rt_period;
9478 old_runtime = sysctl_sched_rt_runtime;
9480 ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
9482 if (!ret && write) {
9483 ret = sched_rt_global_constraints();
9485 sysctl_sched_rt_period = old_period;
9486 sysctl_sched_rt_runtime = old_runtime;
9488 def_rt_bandwidth.rt_runtime = global_rt_runtime();
9489 def_rt_bandwidth.rt_period =
9490 ns_to_ktime(global_rt_period());
9493 mutex_unlock(&mutex);
9498 #ifdef CONFIG_CGROUP_SCHED
9500 /* return corresponding task_group object of a cgroup */
9501 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
9503 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
9504 struct task_group, css);
9507 static struct cgroup_subsys_state *
9508 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
9510 struct task_group *tg, *parent;
9512 if (!cgrp->parent) {
9513 /* This is early initialization for the top cgroup */
9514 return &init_task_group.css;
9517 parent = cgroup_tg(cgrp->parent);
9518 tg = sched_create_group(parent);
9520 return ERR_PTR(-ENOMEM);
9526 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
9528 struct task_group *tg = cgroup_tg(cgrp);
9530 sched_destroy_group(tg);
9534 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9535 struct task_struct *tsk)
9537 #ifdef CONFIG_RT_GROUP_SCHED
9538 if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
9541 /* We don't support RT-tasks being in separate groups */
9542 if (tsk->sched_class != &fair_sched_class)
9550 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9551 struct cgroup *old_cont, struct task_struct *tsk)
9553 sched_move_task(tsk);
9556 #ifdef CONFIG_FAIR_GROUP_SCHED
9557 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
9560 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
9563 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
9565 struct task_group *tg = cgroup_tg(cgrp);
9567 return (u64) tg->shares;
9569 #endif /* CONFIG_FAIR_GROUP_SCHED */
9571 #ifdef CONFIG_RT_GROUP_SCHED
9572 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
9575 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
9578 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
9580 return sched_group_rt_runtime(cgroup_tg(cgrp));
9583 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
9586 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
9589 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
9591 return sched_group_rt_period(cgroup_tg(cgrp));
9593 #endif /* CONFIG_RT_GROUP_SCHED */
9595 static struct cftype cpu_files[] = {
9596 #ifdef CONFIG_FAIR_GROUP_SCHED
9599 .read_u64 = cpu_shares_read_u64,
9600 .write_u64 = cpu_shares_write_u64,
9603 #ifdef CONFIG_RT_GROUP_SCHED
9605 .name = "rt_runtime_us",
9606 .read_s64 = cpu_rt_runtime_read,
9607 .write_s64 = cpu_rt_runtime_write,
9610 .name = "rt_period_us",
9611 .read_u64 = cpu_rt_period_read_uint,
9612 .write_u64 = cpu_rt_period_write_uint,
9617 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
9619 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
9622 struct cgroup_subsys cpu_cgroup_subsys = {
9624 .create = cpu_cgroup_create,
9625 .destroy = cpu_cgroup_destroy,
9626 .can_attach = cpu_cgroup_can_attach,
9627 .attach = cpu_cgroup_attach,
9628 .populate = cpu_cgroup_populate,
9629 .subsys_id = cpu_cgroup_subsys_id,
9633 #endif /* CONFIG_CGROUP_SCHED */
9635 #ifdef CONFIG_CGROUP_CPUACCT
9638 * CPU accounting code for task groups.
9640 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9641 * (balbir@in.ibm.com).
9644 /* track cpu usage of a group of tasks and its child groups */
9646 struct cgroup_subsys_state css;
9647 /* cpuusage holds pointer to a u64-type object on every cpu */
9649 struct cpuacct *parent;
9652 struct cgroup_subsys cpuacct_subsys;
9654 /* return cpu accounting group corresponding to this container */
9655 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
9657 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
9658 struct cpuacct, css);
9661 /* return cpu accounting group to which this task belongs */
9662 static inline struct cpuacct *task_ca(struct task_struct *tsk)
9664 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
9665 struct cpuacct, css);
9668 /* create a new cpu accounting group */
9669 static struct cgroup_subsys_state *cpuacct_create(
9670 struct cgroup_subsys *ss, struct cgroup *cgrp)
9672 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
9675 return ERR_PTR(-ENOMEM);
9677 ca->cpuusage = alloc_percpu(u64);
9678 if (!ca->cpuusage) {
9680 return ERR_PTR(-ENOMEM);
9684 ca->parent = cgroup_ca(cgrp->parent);
9689 /* destroy an existing cpu accounting group */
9691 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
9693 struct cpuacct *ca = cgroup_ca(cgrp);
9695 free_percpu(ca->cpuusage);
9699 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
9701 u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
9704 #ifndef CONFIG_64BIT
9706 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
9708 spin_lock_irq(&cpu_rq(cpu)->lock);
9710 spin_unlock_irq(&cpu_rq(cpu)->lock);
9718 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
9720 u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
9722 #ifndef CONFIG_64BIT
9724 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
9726 spin_lock_irq(&cpu_rq(cpu)->lock);
9728 spin_unlock_irq(&cpu_rq(cpu)->lock);
9734 /* return total cpu usage (in nanoseconds) of a group */
9735 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
9737 struct cpuacct *ca = cgroup_ca(cgrp);
9738 u64 totalcpuusage = 0;
9741 for_each_present_cpu(i)
9742 totalcpuusage += cpuacct_cpuusage_read(ca, i);
9744 return totalcpuusage;
9747 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
9750 struct cpuacct *ca = cgroup_ca(cgrp);
9759 for_each_present_cpu(i)
9760 cpuacct_cpuusage_write(ca, i, 0);
9766 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
9769 struct cpuacct *ca = cgroup_ca(cgroup);
9773 for_each_present_cpu(i) {
9774 percpu = cpuacct_cpuusage_read(ca, i);
9775 seq_printf(m, "%llu ", (unsigned long long) percpu);
9777 seq_printf(m, "\n");
9781 static struct cftype files[] = {
9784 .read_u64 = cpuusage_read,
9785 .write_u64 = cpuusage_write,
9788 .name = "usage_percpu",
9789 .read_seq_string = cpuacct_percpu_seq_read,
9794 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
9796 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
9800 * charge this task's execution time to its accounting group.
9802 * called with rq->lock held.
9804 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
9809 if (unlikely(!cpuacct_subsys.active))
9812 cpu = task_cpu(tsk);
9815 for (; ca; ca = ca->parent) {
9816 u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
9817 *cpuusage += cputime;
9821 struct cgroup_subsys cpuacct_subsys = {
9823 .create = cpuacct_create,
9824 .destroy = cpuacct_destroy,
9825 .populate = cpuacct_populate,
9826 .subsys_id = cpuacct_subsys_id,
9828 #endif /* CONFIG_CGROUP_CPUACCT */