4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/perf_counter.h>
43 #include <linux/security.h>
44 #include <linux/notifier.h>
45 #include <linux/profile.h>
46 #include <linux/freezer.h>
47 #include <linux/vmalloc.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/pid_namespace.h>
51 #include <linux/smp.h>
52 #include <linux/threads.h>
53 #include <linux/timer.h>
54 #include <linux/rcupdate.h>
55 #include <linux/cpu.h>
56 #include <linux/cpuset.h>
57 #include <linux/percpu.h>
58 #include <linux/kthread.h>
59 #include <linux/proc_fs.h>
60 #include <linux/seq_file.h>
61 #include <linux/sysctl.h>
62 #include <linux/syscalls.h>
63 #include <linux/times.h>
64 #include <linux/tsacct_kern.h>
65 #include <linux/kprobes.h>
66 #include <linux/delayacct.h>
67 #include <linux/reciprocal_div.h>
68 #include <linux/unistd.h>
69 #include <linux/pagemap.h>
70 #include <linux/hrtimer.h>
71 #include <linux/tick.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
77 #include <asm/irq_regs.h>
79 #include "sched_cpupri.h"
81 #define CREATE_TRACE_POINTS
82 #include <trace/events/sched.h>
85 * Convert user-nice values [ -20 ... 0 ... 19 ]
86 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
89 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
90 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
91 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
94 * 'User priority' is the nice value converted to something we
95 * can work with better when scaling various scheduler parameters,
96 * it's a [ 0 ... 39 ] range.
98 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
99 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
100 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
103 * Helpers for converting nanosecond timing to jiffy resolution
105 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
107 #define NICE_0_LOAD SCHED_LOAD_SCALE
108 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
111 * These are the 'tuning knobs' of the scheduler:
113 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
114 * Timeslices get refilled after they expire.
116 #define DEF_TIMESLICE (100 * HZ / 1000)
119 * single value that denotes runtime == period, ie unlimited time.
121 #define RUNTIME_INF ((u64)~0ULL)
125 static void double_rq_lock(struct rq *rq1, struct rq *rq2);
128 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
129 * Since cpu_power is a 'constant', we can use a reciprocal divide.
131 static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
133 return reciprocal_divide(load, sg->reciprocal_cpu_power);
137 * Each time a sched group cpu_power is changed,
138 * we must compute its reciprocal value
140 static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
142 sg->__cpu_power += val;
143 sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
147 static inline int rt_policy(int policy)
149 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
154 static inline int task_has_rt_policy(struct task_struct *p)
156 return rt_policy(p->policy);
160 * This is the priority-queue data structure of the RT scheduling class:
162 struct rt_prio_array {
163 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
164 struct list_head queue[MAX_RT_PRIO];
167 struct rt_bandwidth {
168 /* nests inside the rq lock: */
169 spinlock_t rt_runtime_lock;
172 struct hrtimer rt_period_timer;
175 static struct rt_bandwidth def_rt_bandwidth;
177 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
179 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
181 struct rt_bandwidth *rt_b =
182 container_of(timer, struct rt_bandwidth, rt_period_timer);
188 now = hrtimer_cb_get_time(timer);
189 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
194 idle = do_sched_rt_period_timer(rt_b, overrun);
197 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
201 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
203 rt_b->rt_period = ns_to_ktime(period);
204 rt_b->rt_runtime = runtime;
206 spin_lock_init(&rt_b->rt_runtime_lock);
208 hrtimer_init(&rt_b->rt_period_timer,
209 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
210 rt_b->rt_period_timer.function = sched_rt_period_timer;
213 static inline int rt_bandwidth_enabled(void)
215 return sysctl_sched_rt_runtime >= 0;
218 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
222 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
225 if (hrtimer_active(&rt_b->rt_period_timer))
228 spin_lock(&rt_b->rt_runtime_lock);
233 if (hrtimer_active(&rt_b->rt_period_timer))
236 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
237 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
239 soft = hrtimer_get_softexpires(&rt_b->rt_period_timer);
240 hard = hrtimer_get_expires(&rt_b->rt_period_timer);
241 delta = ktime_to_ns(ktime_sub(hard, soft));
242 __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta,
243 HRTIMER_MODE_ABS_PINNED, 0);
245 spin_unlock(&rt_b->rt_runtime_lock);
248 #ifdef CONFIG_RT_GROUP_SCHED
249 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
251 hrtimer_cancel(&rt_b->rt_period_timer);
256 * sched_domains_mutex serializes calls to arch_init_sched_domains,
257 * detach_destroy_domains and partition_sched_domains.
259 static DEFINE_MUTEX(sched_domains_mutex);
261 #ifdef CONFIG_GROUP_SCHED
263 #include <linux/cgroup.h>
267 static LIST_HEAD(task_groups);
269 /* task group related information */
271 #ifdef CONFIG_CGROUP_SCHED
272 struct cgroup_subsys_state css;
275 #ifdef CONFIG_USER_SCHED
279 #ifdef CONFIG_FAIR_GROUP_SCHED
280 /* schedulable entities of this group on each cpu */
281 struct sched_entity **se;
282 /* runqueue "owned" by this group on each cpu */
283 struct cfs_rq **cfs_rq;
284 unsigned long shares;
287 #ifdef CONFIG_RT_GROUP_SCHED
288 struct sched_rt_entity **rt_se;
289 struct rt_rq **rt_rq;
291 struct rt_bandwidth rt_bandwidth;
295 struct list_head list;
297 struct task_group *parent;
298 struct list_head siblings;
299 struct list_head children;
302 #ifdef CONFIG_USER_SCHED
304 /* Helper function to pass uid information to create_sched_user() */
305 void set_tg_uid(struct user_struct *user)
307 user->tg->uid = user->uid;
312 * Every UID task group (including init_task_group aka UID-0) will
313 * be a child to this group.
315 struct task_group root_task_group;
317 #ifdef CONFIG_FAIR_GROUP_SCHED
318 /* Default task group's sched entity on each cpu */
319 static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
320 /* Default task group's cfs_rq on each cpu */
321 static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
322 #endif /* CONFIG_FAIR_GROUP_SCHED */
324 #ifdef CONFIG_RT_GROUP_SCHED
325 static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
326 static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
327 #endif /* CONFIG_RT_GROUP_SCHED */
328 #else /* !CONFIG_USER_SCHED */
329 #define root_task_group init_task_group
330 #endif /* CONFIG_USER_SCHED */
332 /* task_group_lock serializes add/remove of task groups and also changes to
333 * a task group's cpu shares.
335 static DEFINE_SPINLOCK(task_group_lock);
338 static int root_task_group_empty(void)
340 return list_empty(&root_task_group.children);
344 #ifdef CONFIG_FAIR_GROUP_SCHED
345 #ifdef CONFIG_USER_SCHED
346 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
347 #else /* !CONFIG_USER_SCHED */
348 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
349 #endif /* CONFIG_USER_SCHED */
352 * A weight of 0 or 1 can cause arithmetics problems.
353 * A weight of a cfs_rq is the sum of weights of which entities
354 * are queued on this cfs_rq, so a weight of a entity should not be
355 * too large, so as the shares value of a task group.
356 * (The default weight is 1024 - so there's no practical
357 * limitation from this.)
360 #define MAX_SHARES (1UL << 18)
362 static int init_task_group_load = INIT_TASK_GROUP_LOAD;
365 /* Default task group.
366 * Every task in system belong to this group at bootup.
368 struct task_group init_task_group;
370 /* return group to which a task belongs */
371 static inline struct task_group *task_group(struct task_struct *p)
373 struct task_group *tg;
375 #ifdef CONFIG_USER_SCHED
377 tg = __task_cred(p)->user->tg;
379 #elif defined(CONFIG_CGROUP_SCHED)
380 tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
381 struct task_group, css);
383 tg = &init_task_group;
388 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
389 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
391 #ifdef CONFIG_FAIR_GROUP_SCHED
392 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
393 p->se.parent = task_group(p)->se[cpu];
396 #ifdef CONFIG_RT_GROUP_SCHED
397 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
398 p->rt.parent = task_group(p)->rt_se[cpu];
405 static int root_task_group_empty(void)
411 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
412 static inline struct task_group *task_group(struct task_struct *p)
417 #endif /* CONFIG_GROUP_SCHED */
419 /* CFS-related fields in a runqueue */
421 struct load_weight load;
422 unsigned long nr_running;
427 struct rb_root tasks_timeline;
428 struct rb_node *rb_leftmost;
430 struct list_head tasks;
431 struct list_head *balance_iterator;
434 * 'curr' points to currently running entity on this cfs_rq.
435 * It is set to NULL otherwise (i.e when none are currently running).
437 struct sched_entity *curr, *next, *last;
439 unsigned int nr_spread_over;
441 #ifdef CONFIG_FAIR_GROUP_SCHED
442 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
445 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
446 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
447 * (like users, containers etc.)
449 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
450 * list is used during load balance.
452 struct list_head leaf_cfs_rq_list;
453 struct task_group *tg; /* group that "owns" this runqueue */
457 * the part of load.weight contributed by tasks
459 unsigned long task_weight;
462 * h_load = weight * f(tg)
464 * Where f(tg) is the recursive weight fraction assigned to
467 unsigned long h_load;
470 * this cpu's part of tg->shares
472 unsigned long shares;
475 * load.weight at the time we set shares
477 unsigned long rq_weight;
482 /* Real-Time classes' related field in a runqueue: */
484 struct rt_prio_array active;
485 unsigned long rt_nr_running;
486 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
488 int curr; /* highest queued rt task prio */
490 int next; /* next highest */
495 unsigned long rt_nr_migratory;
496 unsigned long rt_nr_total;
498 struct plist_head pushable_tasks;
503 /* Nests inside the rq lock: */
504 spinlock_t rt_runtime_lock;
506 #ifdef CONFIG_RT_GROUP_SCHED
507 unsigned long rt_nr_boosted;
510 struct list_head leaf_rt_rq_list;
511 struct task_group *tg;
512 struct sched_rt_entity *rt_se;
519 * We add the notion of a root-domain which will be used to define per-domain
520 * variables. Each exclusive cpuset essentially defines an island domain by
521 * fully partitioning the member cpus from any other cpuset. Whenever a new
522 * exclusive cpuset is created, we also create and attach a new root-domain
529 cpumask_var_t online;
532 * The "RT overload" flag: it gets set if a CPU has more than
533 * one runnable RT task.
535 cpumask_var_t rto_mask;
538 struct cpupri cpupri;
540 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
542 * Preferred wake up cpu nominated by sched_mc balance that will be
543 * used when most cpus are idle in the system indicating overall very
544 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
546 unsigned int sched_mc_preferred_wakeup_cpu;
551 * By default the system creates a single root-domain with all cpus as
552 * members (mimicking the global state we have today).
554 static struct root_domain def_root_domain;
559 * This is the main, per-CPU runqueue data structure.
561 * Locking rule: those places that want to lock multiple runqueues
562 * (such as the load balancing or the thread migration code), lock
563 * acquire operations must be ordered by ascending &runqueue.
570 * nr_running and cpu_load should be in the same cacheline because
571 * remote CPUs use both these fields when doing load calculation.
573 unsigned long nr_running;
574 #define CPU_LOAD_IDX_MAX 5
575 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
577 unsigned long last_tick_seen;
578 unsigned char in_nohz_recently;
580 /* capture load from *all* tasks on this cpu: */
581 struct load_weight load;
582 unsigned long nr_load_updates;
584 u64 nr_migrations_in;
589 #ifdef CONFIG_FAIR_GROUP_SCHED
590 /* list of leaf cfs_rq on this cpu: */
591 struct list_head leaf_cfs_rq_list;
593 #ifdef CONFIG_RT_GROUP_SCHED
594 struct list_head leaf_rt_rq_list;
598 * This is part of a global counter where only the total sum
599 * over all CPUs matters. A task can increase this counter on
600 * one CPU and if it got migrated afterwards it may decrease
601 * it on another CPU. Always updated under the runqueue lock:
603 unsigned long nr_uninterruptible;
605 struct task_struct *curr, *idle;
606 unsigned long next_balance;
607 struct mm_struct *prev_mm;
614 struct root_domain *rd;
615 struct sched_domain *sd;
617 unsigned char idle_at_tick;
618 /* For active balancing */
621 /* cpu of this runqueue: */
625 unsigned long avg_load_per_task;
627 struct task_struct *migration_thread;
628 struct list_head migration_queue;
631 /* calc_load related fields */
632 unsigned long calc_load_update;
633 long calc_load_active;
635 #ifdef CONFIG_SCHED_HRTICK
637 int hrtick_csd_pending;
638 struct call_single_data hrtick_csd;
640 struct hrtimer hrtick_timer;
643 #ifdef CONFIG_SCHEDSTATS
645 struct sched_info rq_sched_info;
646 unsigned long long rq_cpu_time;
647 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
649 /* sys_sched_yield() stats */
650 unsigned int yld_count;
652 /* schedule() stats */
653 unsigned int sched_switch;
654 unsigned int sched_count;
655 unsigned int sched_goidle;
657 /* try_to_wake_up() stats */
658 unsigned int ttwu_count;
659 unsigned int ttwu_local;
662 unsigned int bkl_count;
666 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
668 static inline void check_preempt_curr(struct rq *rq, struct task_struct *p, int sync)
670 rq->curr->sched_class->check_preempt_curr(rq, p, sync);
673 static inline int cpu_of(struct rq *rq)
683 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
684 * See detach_destroy_domains: synchronize_sched for details.
686 * The domain tree of any CPU may only be accessed from within
687 * preempt-disabled sections.
689 #define for_each_domain(cpu, __sd) \
690 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
692 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
693 #define this_rq() (&__get_cpu_var(runqueues))
694 #define task_rq(p) cpu_rq(task_cpu(p))
695 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
696 #define raw_rq() (&__raw_get_cpu_var(runqueues))
698 inline void update_rq_clock(struct rq *rq)
700 rq->clock = sched_clock_cpu(cpu_of(rq));
704 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
706 #ifdef CONFIG_SCHED_DEBUG
707 # define const_debug __read_mostly
709 # define const_debug static const
715 * Returns true if the current cpu runqueue is locked.
716 * This interface allows printk to be called with the runqueue lock
717 * held and know whether or not it is OK to wake up the klogd.
719 int runqueue_is_locked(void)
722 struct rq *rq = cpu_rq(cpu);
725 ret = spin_is_locked(&rq->lock);
731 * Debugging: various feature bits
734 #define SCHED_FEAT(name, enabled) \
735 __SCHED_FEAT_##name ,
738 #include "sched_features.h"
743 #define SCHED_FEAT(name, enabled) \
744 (1UL << __SCHED_FEAT_##name) * enabled |
746 const_debug unsigned int sysctl_sched_features =
747 #include "sched_features.h"
752 #ifdef CONFIG_SCHED_DEBUG
753 #define SCHED_FEAT(name, enabled) \
756 static __read_mostly char *sched_feat_names[] = {
757 #include "sched_features.h"
763 static int sched_feat_show(struct seq_file *m, void *v)
767 for (i = 0; sched_feat_names[i]; i++) {
768 if (!(sysctl_sched_features & (1UL << i)))
770 seq_printf(m, "%s ", sched_feat_names[i]);
778 sched_feat_write(struct file *filp, const char __user *ubuf,
779 size_t cnt, loff_t *ppos)
789 if (copy_from_user(&buf, ubuf, cnt))
794 if (strncmp(buf, "NO_", 3) == 0) {
799 for (i = 0; sched_feat_names[i]; i++) {
800 int len = strlen(sched_feat_names[i]);
802 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
804 sysctl_sched_features &= ~(1UL << i);
806 sysctl_sched_features |= (1UL << i);
811 if (!sched_feat_names[i])
819 static int sched_feat_open(struct inode *inode, struct file *filp)
821 return single_open(filp, sched_feat_show, NULL);
824 static struct file_operations sched_feat_fops = {
825 .open = sched_feat_open,
826 .write = sched_feat_write,
829 .release = single_release,
832 static __init int sched_init_debug(void)
834 debugfs_create_file("sched_features", 0644, NULL, NULL,
839 late_initcall(sched_init_debug);
843 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
846 * Number of tasks to iterate in a single balance run.
847 * Limited because this is done with IRQs disabled.
849 const_debug unsigned int sysctl_sched_nr_migrate = 32;
852 * ratelimit for updating the group shares.
855 unsigned int sysctl_sched_shares_ratelimit = 250000;
858 * Inject some fuzzyness into changing the per-cpu group shares
859 * this avoids remote rq-locks at the expense of fairness.
862 unsigned int sysctl_sched_shares_thresh = 4;
865 * period over which we measure -rt task cpu usage in us.
868 unsigned int sysctl_sched_rt_period = 1000000;
870 static __read_mostly int scheduler_running;
873 * part of the period that we allow rt tasks to run in us.
876 int sysctl_sched_rt_runtime = 950000;
878 static inline u64 global_rt_period(void)
880 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
883 static inline u64 global_rt_runtime(void)
885 if (sysctl_sched_rt_runtime < 0)
888 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
891 #ifndef prepare_arch_switch
892 # define prepare_arch_switch(next) do { } while (0)
894 #ifndef finish_arch_switch
895 # define finish_arch_switch(prev) do { } while (0)
898 static inline int task_current(struct rq *rq, struct task_struct *p)
900 return rq->curr == p;
903 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
904 static inline int task_running(struct rq *rq, struct task_struct *p)
906 return task_current(rq, p);
909 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
913 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
915 #ifdef CONFIG_DEBUG_SPINLOCK
916 /* this is a valid case when another task releases the spinlock */
917 rq->lock.owner = current;
920 * If we are tracking spinlock dependencies then we have to
921 * fix up the runqueue lock - which gets 'carried over' from
924 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
926 spin_unlock_irq(&rq->lock);
929 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
930 static inline int task_running(struct rq *rq, struct task_struct *p)
935 return task_current(rq, p);
939 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
943 * We can optimise this out completely for !SMP, because the
944 * SMP rebalancing from interrupt is the only thing that cares
949 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
950 spin_unlock_irq(&rq->lock);
952 spin_unlock(&rq->lock);
956 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
960 * After ->oncpu is cleared, the task can be moved to a different CPU.
961 * We must ensure this doesn't happen until the switch is completely
967 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
971 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
974 * __task_rq_lock - lock the runqueue a given task resides on.
975 * Must be called interrupts disabled.
977 static inline struct rq *__task_rq_lock(struct task_struct *p)
981 struct rq *rq = task_rq(p);
982 spin_lock(&rq->lock);
983 if (likely(rq == task_rq(p)))
985 spin_unlock(&rq->lock);
990 * task_rq_lock - lock the runqueue a given task resides on and disable
991 * interrupts. Note the ordering: we can safely lookup the task_rq without
992 * explicitly disabling preemption.
994 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
1000 local_irq_save(*flags);
1002 spin_lock(&rq->lock);
1003 if (likely(rq == task_rq(p)))
1005 spin_unlock_irqrestore(&rq->lock, *flags);
1009 void task_rq_unlock_wait(struct task_struct *p)
1011 struct rq *rq = task_rq(p);
1013 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1014 spin_unlock_wait(&rq->lock);
1017 static void __task_rq_unlock(struct rq *rq)
1018 __releases(rq->lock)
1020 spin_unlock(&rq->lock);
1023 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
1024 __releases(rq->lock)
1026 spin_unlock_irqrestore(&rq->lock, *flags);
1030 * this_rq_lock - lock this runqueue and disable interrupts.
1032 static struct rq *this_rq_lock(void)
1033 __acquires(rq->lock)
1037 local_irq_disable();
1039 spin_lock(&rq->lock);
1044 #ifdef CONFIG_SCHED_HRTICK
1046 * Use HR-timers to deliver accurate preemption points.
1048 * Its all a bit involved since we cannot program an hrt while holding the
1049 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1052 * When we get rescheduled we reprogram the hrtick_timer outside of the
1058 * - enabled by features
1059 * - hrtimer is actually high res
1061 static inline int hrtick_enabled(struct rq *rq)
1063 if (!sched_feat(HRTICK))
1065 if (!cpu_active(cpu_of(rq)))
1067 return hrtimer_is_hres_active(&rq->hrtick_timer);
1070 static void hrtick_clear(struct rq *rq)
1072 if (hrtimer_active(&rq->hrtick_timer))
1073 hrtimer_cancel(&rq->hrtick_timer);
1077 * High-resolution timer tick.
1078 * Runs from hardirq context with interrupts disabled.
1080 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1082 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1084 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1086 spin_lock(&rq->lock);
1087 update_rq_clock(rq);
1088 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1089 spin_unlock(&rq->lock);
1091 return HRTIMER_NORESTART;
1096 * called from hardirq (IPI) context
1098 static void __hrtick_start(void *arg)
1100 struct rq *rq = arg;
1102 spin_lock(&rq->lock);
1103 hrtimer_restart(&rq->hrtick_timer);
1104 rq->hrtick_csd_pending = 0;
1105 spin_unlock(&rq->lock);
1109 * Called to set the hrtick timer state.
1111 * called with rq->lock held and irqs disabled
1113 static void hrtick_start(struct rq *rq, u64 delay)
1115 struct hrtimer *timer = &rq->hrtick_timer;
1116 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
1118 hrtimer_set_expires(timer, time);
1120 if (rq == this_rq()) {
1121 hrtimer_restart(timer);
1122 } else if (!rq->hrtick_csd_pending) {
1123 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
1124 rq->hrtick_csd_pending = 1;
1129 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1131 int cpu = (int)(long)hcpu;
1134 case CPU_UP_CANCELED:
1135 case CPU_UP_CANCELED_FROZEN:
1136 case CPU_DOWN_PREPARE:
1137 case CPU_DOWN_PREPARE_FROZEN:
1139 case CPU_DEAD_FROZEN:
1140 hrtick_clear(cpu_rq(cpu));
1147 static __init void init_hrtick(void)
1149 hotcpu_notifier(hotplug_hrtick, 0);
1153 * Called to set the hrtick timer state.
1155 * called with rq->lock held and irqs disabled
1157 static void hrtick_start(struct rq *rq, u64 delay)
1159 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
1160 HRTIMER_MODE_REL_PINNED, 0);
1163 static inline void init_hrtick(void)
1166 #endif /* CONFIG_SMP */
1168 static void init_rq_hrtick(struct rq *rq)
1171 rq->hrtick_csd_pending = 0;
1173 rq->hrtick_csd.flags = 0;
1174 rq->hrtick_csd.func = __hrtick_start;
1175 rq->hrtick_csd.info = rq;
1178 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1179 rq->hrtick_timer.function = hrtick;
1181 #else /* CONFIG_SCHED_HRTICK */
1182 static inline void hrtick_clear(struct rq *rq)
1186 static inline void init_rq_hrtick(struct rq *rq)
1190 static inline void init_hrtick(void)
1193 #endif /* CONFIG_SCHED_HRTICK */
1196 * resched_task - mark a task 'to be rescheduled now'.
1198 * On UP this means the setting of the need_resched flag, on SMP it
1199 * might also involve a cross-CPU call to trigger the scheduler on
1204 #ifndef tsk_is_polling
1205 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1208 static void resched_task(struct task_struct *p)
1212 assert_spin_locked(&task_rq(p)->lock);
1214 if (test_tsk_need_resched(p))
1217 set_tsk_need_resched(p);
1220 if (cpu == smp_processor_id())
1223 /* NEED_RESCHED must be visible before we test polling */
1225 if (!tsk_is_polling(p))
1226 smp_send_reschedule(cpu);
1229 static void resched_cpu(int cpu)
1231 struct rq *rq = cpu_rq(cpu);
1232 unsigned long flags;
1234 if (!spin_trylock_irqsave(&rq->lock, flags))
1236 resched_task(cpu_curr(cpu));
1237 spin_unlock_irqrestore(&rq->lock, flags);
1242 * When add_timer_on() enqueues a timer into the timer wheel of an
1243 * idle CPU then this timer might expire before the next timer event
1244 * which is scheduled to wake up that CPU. In case of a completely
1245 * idle system the next event might even be infinite time into the
1246 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1247 * leaves the inner idle loop so the newly added timer is taken into
1248 * account when the CPU goes back to idle and evaluates the timer
1249 * wheel for the next timer event.
1251 void wake_up_idle_cpu(int cpu)
1253 struct rq *rq = cpu_rq(cpu);
1255 if (cpu == smp_processor_id())
1259 * This is safe, as this function is called with the timer
1260 * wheel base lock of (cpu) held. When the CPU is on the way
1261 * to idle and has not yet set rq->curr to idle then it will
1262 * be serialized on the timer wheel base lock and take the new
1263 * timer into account automatically.
1265 if (rq->curr != rq->idle)
1269 * We can set TIF_RESCHED on the idle task of the other CPU
1270 * lockless. The worst case is that the other CPU runs the
1271 * idle task through an additional NOOP schedule()
1273 set_tsk_need_resched(rq->idle);
1275 /* NEED_RESCHED must be visible before we test polling */
1277 if (!tsk_is_polling(rq->idle))
1278 smp_send_reschedule(cpu);
1280 #endif /* CONFIG_NO_HZ */
1282 #else /* !CONFIG_SMP */
1283 static void resched_task(struct task_struct *p)
1285 assert_spin_locked(&task_rq(p)->lock);
1286 set_tsk_need_resched(p);
1288 #endif /* CONFIG_SMP */
1290 #if BITS_PER_LONG == 32
1291 # define WMULT_CONST (~0UL)
1293 # define WMULT_CONST (1UL << 32)
1296 #define WMULT_SHIFT 32
1299 * Shift right and round:
1301 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1304 * delta *= weight / lw
1306 static unsigned long
1307 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1308 struct load_weight *lw)
1312 if (!lw->inv_weight) {
1313 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1316 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1320 tmp = (u64)delta_exec * weight;
1322 * Check whether we'd overflow the 64-bit multiplication:
1324 if (unlikely(tmp > WMULT_CONST))
1325 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1328 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1330 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1333 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1339 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1346 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1347 * of tasks with abnormal "nice" values across CPUs the contribution that
1348 * each task makes to its run queue's load is weighted according to its
1349 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1350 * scaled version of the new time slice allocation that they receive on time
1354 #define WEIGHT_IDLEPRIO 3
1355 #define WMULT_IDLEPRIO 1431655765
1358 * Nice levels are multiplicative, with a gentle 10% change for every
1359 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1360 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1361 * that remained on nice 0.
1363 * The "10% effect" is relative and cumulative: from _any_ nice level,
1364 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1365 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1366 * If a task goes up by ~10% and another task goes down by ~10% then
1367 * the relative distance between them is ~25%.)
1369 static const int prio_to_weight[40] = {
1370 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1371 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1372 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1373 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1374 /* 0 */ 1024, 820, 655, 526, 423,
1375 /* 5 */ 335, 272, 215, 172, 137,
1376 /* 10 */ 110, 87, 70, 56, 45,
1377 /* 15 */ 36, 29, 23, 18, 15,
1381 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1383 * In cases where the weight does not change often, we can use the
1384 * precalculated inverse to speed up arithmetics by turning divisions
1385 * into multiplications:
1387 static const u32 prio_to_wmult[40] = {
1388 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1389 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1390 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1391 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1392 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1393 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1394 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1395 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1398 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
1401 * runqueue iterator, to support SMP load-balancing between different
1402 * scheduling classes, without having to expose their internal data
1403 * structures to the load-balancing proper:
1405 struct rq_iterator {
1407 struct task_struct *(*start)(void *);
1408 struct task_struct *(*next)(void *);
1412 static unsigned long
1413 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
1414 unsigned long max_load_move, struct sched_domain *sd,
1415 enum cpu_idle_type idle, int *all_pinned,
1416 int *this_best_prio, struct rq_iterator *iterator);
1419 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
1420 struct sched_domain *sd, enum cpu_idle_type idle,
1421 struct rq_iterator *iterator);
1424 /* Time spent by the tasks of the cpu accounting group executing in ... */
1425 enum cpuacct_stat_index {
1426 CPUACCT_STAT_USER, /* ... user mode */
1427 CPUACCT_STAT_SYSTEM, /* ... kernel mode */
1429 CPUACCT_STAT_NSTATS,
1432 #ifdef CONFIG_CGROUP_CPUACCT
1433 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1434 static void cpuacct_update_stats(struct task_struct *tsk,
1435 enum cpuacct_stat_index idx, cputime_t val);
1437 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1438 static inline void cpuacct_update_stats(struct task_struct *tsk,
1439 enum cpuacct_stat_index idx, cputime_t val) {}
1442 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1444 update_load_add(&rq->load, load);
1447 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1449 update_load_sub(&rq->load, load);
1452 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1453 typedef int (*tg_visitor)(struct task_group *, void *);
1456 * Iterate the full tree, calling @down when first entering a node and @up when
1457 * leaving it for the final time.
1459 static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
1461 struct task_group *parent, *child;
1465 parent = &root_task_group;
1467 ret = (*down)(parent, data);
1470 list_for_each_entry_rcu(child, &parent->children, siblings) {
1477 ret = (*up)(parent, data);
1482 parent = parent->parent;
1491 static int tg_nop(struct task_group *tg, void *data)
1498 static unsigned long source_load(int cpu, int type);
1499 static unsigned long target_load(int cpu, int type);
1500 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1502 static unsigned long cpu_avg_load_per_task(int cpu)
1504 struct rq *rq = cpu_rq(cpu);
1505 unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
1508 rq->avg_load_per_task = rq->load.weight / nr_running;
1510 rq->avg_load_per_task = 0;
1512 return rq->avg_load_per_task;
1515 #ifdef CONFIG_FAIR_GROUP_SCHED
1517 static void __set_se_shares(struct sched_entity *se, unsigned long shares);
1520 * Calculate and set the cpu's group shares.
1523 update_group_shares_cpu(struct task_group *tg, int cpu,
1524 unsigned long sd_shares, unsigned long sd_rq_weight)
1526 unsigned long rq_weight;
1527 unsigned long shares;
1533 rq_weight = tg->cfs_rq[cpu]->rq_weight;
1536 rq_weight = NICE_0_LOAD;
1540 * \Sum shares * rq_weight
1541 * shares = -----------------------
1545 shares = (sd_shares * rq_weight) / sd_rq_weight;
1546 shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
1548 if (abs(shares - tg->se[cpu]->load.weight) >
1549 sysctl_sched_shares_thresh) {
1550 struct rq *rq = cpu_rq(cpu);
1551 unsigned long flags;
1553 spin_lock_irqsave(&rq->lock, flags);
1554 tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
1555 __set_se_shares(tg->se[cpu], shares);
1556 spin_unlock_irqrestore(&rq->lock, flags);
1561 * Re-compute the task group their per cpu shares over the given domain.
1562 * This needs to be done in a bottom-up fashion because the rq weight of a
1563 * parent group depends on the shares of its child groups.
1565 static int tg_shares_up(struct task_group *tg, void *data)
1567 unsigned long weight, rq_weight = 0, eff_weight = 0;
1568 unsigned long shares = 0;
1569 struct sched_domain *sd = data;
1572 for_each_cpu(i, sched_domain_span(sd)) {
1574 * If there are currently no tasks on the cpu pretend there
1575 * is one of average load so that when a new task gets to
1576 * run here it will not get delayed by group starvation.
1578 weight = tg->cfs_rq[i]->load.weight;
1579 tg->cfs_rq[i]->rq_weight = weight;
1580 rq_weight += weight;
1583 weight = NICE_0_LOAD;
1585 eff_weight += weight;
1586 shares += tg->cfs_rq[i]->shares;
1589 if ((!shares && rq_weight) || shares > tg->shares)
1590 shares = tg->shares;
1592 if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
1593 shares = tg->shares;
1595 for_each_cpu(i, sched_domain_span(sd)) {
1596 unsigned long sd_rq_weight = rq_weight;
1598 if (!tg->cfs_rq[i]->rq_weight)
1599 sd_rq_weight = eff_weight;
1601 update_group_shares_cpu(tg, i, shares, sd_rq_weight);
1608 * Compute the cpu's hierarchical load factor for each task group.
1609 * This needs to be done in a top-down fashion because the load of a child
1610 * group is a fraction of its parents load.
1612 static int tg_load_down(struct task_group *tg, void *data)
1615 long cpu = (long)data;
1618 load = cpu_rq(cpu)->load.weight;
1620 load = tg->parent->cfs_rq[cpu]->h_load;
1621 load *= tg->cfs_rq[cpu]->shares;
1622 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
1625 tg->cfs_rq[cpu]->h_load = load;
1630 static void update_shares(struct sched_domain *sd)
1632 u64 now = cpu_clock(raw_smp_processor_id());
1633 s64 elapsed = now - sd->last_update;
1635 if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
1636 sd->last_update = now;
1637 walk_tg_tree(tg_nop, tg_shares_up, sd);
1641 static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1643 spin_unlock(&rq->lock);
1645 spin_lock(&rq->lock);
1648 static void update_h_load(long cpu)
1650 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
1655 static inline void update_shares(struct sched_domain *sd)
1659 static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1665 #ifdef CONFIG_PREEMPT
1668 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1669 * way at the expense of forcing extra atomic operations in all
1670 * invocations. This assures that the double_lock is acquired using the
1671 * same underlying policy as the spinlock_t on this architecture, which
1672 * reduces latency compared to the unfair variant below. However, it
1673 * also adds more overhead and therefore may reduce throughput.
1675 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1676 __releases(this_rq->lock)
1677 __acquires(busiest->lock)
1678 __acquires(this_rq->lock)
1680 spin_unlock(&this_rq->lock);
1681 double_rq_lock(this_rq, busiest);
1688 * Unfair double_lock_balance: Optimizes throughput at the expense of
1689 * latency by eliminating extra atomic operations when the locks are
1690 * already in proper order on entry. This favors lower cpu-ids and will
1691 * grant the double lock to lower cpus over higher ids under contention,
1692 * regardless of entry order into the function.
1694 static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1695 __releases(this_rq->lock)
1696 __acquires(busiest->lock)
1697 __acquires(this_rq->lock)
1701 if (unlikely(!spin_trylock(&busiest->lock))) {
1702 if (busiest < this_rq) {
1703 spin_unlock(&this_rq->lock);
1704 spin_lock(&busiest->lock);
1705 spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING);
1708 spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING);
1713 #endif /* CONFIG_PREEMPT */
1716 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1718 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1720 if (unlikely(!irqs_disabled())) {
1721 /* printk() doesn't work good under rq->lock */
1722 spin_unlock(&this_rq->lock);
1726 return _double_lock_balance(this_rq, busiest);
1729 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1730 __releases(busiest->lock)
1732 spin_unlock(&busiest->lock);
1733 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1737 #ifdef CONFIG_FAIR_GROUP_SCHED
1738 static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
1741 cfs_rq->shares = shares;
1746 static void calc_load_account_active(struct rq *this_rq);
1748 #include "sched_stats.h"
1749 #include "sched_idletask.c"
1750 #include "sched_fair.c"
1751 #include "sched_rt.c"
1752 #ifdef CONFIG_SCHED_DEBUG
1753 # include "sched_debug.c"
1756 #define sched_class_highest (&rt_sched_class)
1757 #define for_each_class(class) \
1758 for (class = sched_class_highest; class; class = class->next)
1760 static void inc_nr_running(struct rq *rq)
1765 static void dec_nr_running(struct rq *rq)
1770 static void set_load_weight(struct task_struct *p)
1772 if (task_has_rt_policy(p)) {
1773 p->se.load.weight = prio_to_weight[0] * 2;
1774 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1779 * SCHED_IDLE tasks get minimal weight:
1781 if (p->policy == SCHED_IDLE) {
1782 p->se.load.weight = WEIGHT_IDLEPRIO;
1783 p->se.load.inv_weight = WMULT_IDLEPRIO;
1787 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1788 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1791 static void update_avg(u64 *avg, u64 sample)
1793 s64 diff = sample - *avg;
1797 static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
1800 p->se.start_runtime = p->se.sum_exec_runtime;
1802 sched_info_queued(p);
1803 p->sched_class->enqueue_task(rq, p, wakeup);
1807 static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
1810 if (p->se.last_wakeup) {
1811 update_avg(&p->se.avg_overlap,
1812 p->se.sum_exec_runtime - p->se.last_wakeup);
1813 p->se.last_wakeup = 0;
1815 update_avg(&p->se.avg_wakeup,
1816 sysctl_sched_wakeup_granularity);
1820 sched_info_dequeued(p);
1821 p->sched_class->dequeue_task(rq, p, sleep);
1826 * __normal_prio - return the priority that is based on the static prio
1828 static inline int __normal_prio(struct task_struct *p)
1830 return p->static_prio;
1834 * Calculate the expected normal priority: i.e. priority
1835 * without taking RT-inheritance into account. Might be
1836 * boosted by interactivity modifiers. Changes upon fork,
1837 * setprio syscalls, and whenever the interactivity
1838 * estimator recalculates.
1840 static inline int normal_prio(struct task_struct *p)
1844 if (task_has_rt_policy(p))
1845 prio = MAX_RT_PRIO-1 - p->rt_priority;
1847 prio = __normal_prio(p);
1852 * Calculate the current priority, i.e. the priority
1853 * taken into account by the scheduler. This value might
1854 * be boosted by RT tasks, or might be boosted by
1855 * interactivity modifiers. Will be RT if the task got
1856 * RT-boosted. If not then it returns p->normal_prio.
1858 static int effective_prio(struct task_struct *p)
1860 p->normal_prio = normal_prio(p);
1862 * If we are RT tasks or we were boosted to RT priority,
1863 * keep the priority unchanged. Otherwise, update priority
1864 * to the normal priority:
1866 if (!rt_prio(p->prio))
1867 return p->normal_prio;
1872 * activate_task - move a task to the runqueue.
1874 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
1876 if (task_contributes_to_load(p))
1877 rq->nr_uninterruptible--;
1879 enqueue_task(rq, p, wakeup);
1884 * deactivate_task - remove a task from the runqueue.
1886 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
1888 if (task_contributes_to_load(p))
1889 rq->nr_uninterruptible++;
1891 dequeue_task(rq, p, sleep);
1896 * task_curr - is this task currently executing on a CPU?
1897 * @p: the task in question.
1899 inline int task_curr(const struct task_struct *p)
1901 return cpu_curr(task_cpu(p)) == p;
1904 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1906 set_task_rq(p, cpu);
1909 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1910 * successfuly executed on another CPU. We must ensure that updates of
1911 * per-task data have been completed by this moment.
1914 task_thread_info(p)->cpu = cpu;
1918 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1919 const struct sched_class *prev_class,
1920 int oldprio, int running)
1922 if (prev_class != p->sched_class) {
1923 if (prev_class->switched_from)
1924 prev_class->switched_from(rq, p, running);
1925 p->sched_class->switched_to(rq, p, running);
1927 p->sched_class->prio_changed(rq, p, oldprio, running);
1932 /* Used instead of source_load when we know the type == 0 */
1933 static unsigned long weighted_cpuload(const int cpu)
1935 return cpu_rq(cpu)->load.weight;
1939 * Is this task likely cache-hot:
1942 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1947 * Buddy candidates are cache hot:
1949 if (sched_feat(CACHE_HOT_BUDDY) &&
1950 (&p->se == cfs_rq_of(&p->se)->next ||
1951 &p->se == cfs_rq_of(&p->se)->last))
1954 if (p->sched_class != &fair_sched_class)
1957 if (sysctl_sched_migration_cost == -1)
1959 if (sysctl_sched_migration_cost == 0)
1962 delta = now - p->se.exec_start;
1964 return delta < (s64)sysctl_sched_migration_cost;
1968 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1970 int old_cpu = task_cpu(p);
1971 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
1972 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1973 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
1976 clock_offset = old_rq->clock - new_rq->clock;
1978 trace_sched_migrate_task(p, new_cpu);
1980 #ifdef CONFIG_SCHEDSTATS
1981 if (p->se.wait_start)
1982 p->se.wait_start -= clock_offset;
1983 if (p->se.sleep_start)
1984 p->se.sleep_start -= clock_offset;
1985 if (p->se.block_start)
1986 p->se.block_start -= clock_offset;
1988 if (old_cpu != new_cpu) {
1989 p->se.nr_migrations++;
1990 new_rq->nr_migrations_in++;
1991 #ifdef CONFIG_SCHEDSTATS
1992 if (task_hot(p, old_rq->clock, NULL))
1993 schedstat_inc(p, se.nr_forced2_migrations);
1995 perf_swcounter_event(PERF_COUNT_SW_CPU_MIGRATIONS,
1998 p->se.vruntime -= old_cfsrq->min_vruntime -
1999 new_cfsrq->min_vruntime;
2001 __set_task_cpu(p, new_cpu);
2004 struct migration_req {
2005 struct list_head list;
2007 struct task_struct *task;
2010 struct completion done;
2014 * The task's runqueue lock must be held.
2015 * Returns true if you have to wait for migration thread.
2018 migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
2020 struct rq *rq = task_rq(p);
2023 * If the task is not on a runqueue (and not running), then
2024 * it is sufficient to simply update the task's cpu field.
2026 if (!p->se.on_rq && !task_running(rq, p)) {
2027 set_task_cpu(p, dest_cpu);
2031 init_completion(&req->done);
2033 req->dest_cpu = dest_cpu;
2034 list_add(&req->list, &rq->migration_queue);
2040 * wait_task_context_switch - wait for a thread to complete at least one
2043 * @p must not be current.
2045 void wait_task_context_switch(struct task_struct *p)
2047 unsigned long nvcsw, nivcsw, flags;
2055 * The runqueue is assigned before the actual context
2056 * switch. We need to take the runqueue lock.
2058 * We could check initially without the lock but it is
2059 * very likely that we need to take the lock in every
2062 rq = task_rq_lock(p, &flags);
2063 running = task_running(rq, p);
2064 task_rq_unlock(rq, &flags);
2066 if (likely(!running))
2069 * The switch count is incremented before the actual
2070 * context switch. We thus wait for two switches to be
2071 * sure at least one completed.
2073 if ((p->nvcsw - nvcsw) > 1)
2075 if ((p->nivcsw - nivcsw) > 1)
2083 * wait_task_inactive - wait for a thread to unschedule.
2085 * If @match_state is nonzero, it's the @p->state value just checked and
2086 * not expected to change. If it changes, i.e. @p might have woken up,
2087 * then return zero. When we succeed in waiting for @p to be off its CPU,
2088 * we return a positive number (its total switch count). If a second call
2089 * a short while later returns the same number, the caller can be sure that
2090 * @p has remained unscheduled the whole time.
2092 * The caller must ensure that the task *will* unschedule sometime soon,
2093 * else this function might spin for a *long* time. This function can't
2094 * be called with interrupts off, or it may introduce deadlock with
2095 * smp_call_function() if an IPI is sent by the same process we are
2096 * waiting to become inactive.
2098 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
2100 unsigned long flags;
2107 * We do the initial early heuristics without holding
2108 * any task-queue locks at all. We'll only try to get
2109 * the runqueue lock when things look like they will
2115 * If the task is actively running on another CPU
2116 * still, just relax and busy-wait without holding
2119 * NOTE! Since we don't hold any locks, it's not
2120 * even sure that "rq" stays as the right runqueue!
2121 * But we don't care, since "task_running()" will
2122 * return false if the runqueue has changed and p
2123 * is actually now running somewhere else!
2125 while (task_running(rq, p)) {
2126 if (match_state && unlikely(p->state != match_state))
2132 * Ok, time to look more closely! We need the rq
2133 * lock now, to be *sure*. If we're wrong, we'll
2134 * just go back and repeat.
2136 rq = task_rq_lock(p, &flags);
2137 trace_sched_wait_task(rq, p);
2138 running = task_running(rq, p);
2139 on_rq = p->se.on_rq;
2141 if (!match_state || p->state == match_state)
2142 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
2143 task_rq_unlock(rq, &flags);
2146 * If it changed from the expected state, bail out now.
2148 if (unlikely(!ncsw))
2152 * Was it really running after all now that we
2153 * checked with the proper locks actually held?
2155 * Oops. Go back and try again..
2157 if (unlikely(running)) {
2163 * It's not enough that it's not actively running,
2164 * it must be off the runqueue _entirely_, and not
2167 * So if it was still runnable (but just not actively
2168 * running right now), it's preempted, and we should
2169 * yield - it could be a while.
2171 if (unlikely(on_rq)) {
2172 schedule_timeout_uninterruptible(1);
2177 * Ahh, all good. It wasn't running, and it wasn't
2178 * runnable, which means that it will never become
2179 * running in the future either. We're all done!
2188 * kick_process - kick a running thread to enter/exit the kernel
2189 * @p: the to-be-kicked thread
2191 * Cause a process which is running on another CPU to enter
2192 * kernel-mode, without any delay. (to get signals handled.)
2194 * NOTE: this function doesnt have to take the runqueue lock,
2195 * because all it wants to ensure is that the remote task enters
2196 * the kernel. If the IPI races and the task has been migrated
2197 * to another CPU then no harm is done and the purpose has been
2200 void kick_process(struct task_struct *p)
2206 if ((cpu != smp_processor_id()) && task_curr(p))
2207 smp_send_reschedule(cpu);
2210 EXPORT_SYMBOL_GPL(kick_process);
2213 * Return a low guess at the load of a migration-source cpu weighted
2214 * according to the scheduling class and "nice" value.
2216 * We want to under-estimate the load of migration sources, to
2217 * balance conservatively.
2219 static unsigned long source_load(int cpu, int type)
2221 struct rq *rq = cpu_rq(cpu);
2222 unsigned long total = weighted_cpuload(cpu);
2224 if (type == 0 || !sched_feat(LB_BIAS))
2227 return min(rq->cpu_load[type-1], total);
2231 * Return a high guess at the load of a migration-target cpu weighted
2232 * according to the scheduling class and "nice" value.
2234 static unsigned long target_load(int cpu, int type)
2236 struct rq *rq = cpu_rq(cpu);
2237 unsigned long total = weighted_cpuload(cpu);
2239 if (type == 0 || !sched_feat(LB_BIAS))
2242 return max(rq->cpu_load[type-1], total);
2246 * find_idlest_group finds and returns the least busy CPU group within the
2249 static struct sched_group *
2250 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
2252 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
2253 unsigned long min_load = ULONG_MAX, this_load = 0;
2254 int load_idx = sd->forkexec_idx;
2255 int imbalance = 100 + (sd->imbalance_pct-100)/2;
2258 unsigned long load, avg_load;
2262 /* Skip over this group if it has no CPUs allowed */
2263 if (!cpumask_intersects(sched_group_cpus(group),
2267 local_group = cpumask_test_cpu(this_cpu,
2268 sched_group_cpus(group));
2270 /* Tally up the load of all CPUs in the group */
2273 for_each_cpu(i, sched_group_cpus(group)) {
2274 /* Bias balancing toward cpus of our domain */
2276 load = source_load(i, load_idx);
2278 load = target_load(i, load_idx);
2283 /* Adjust by relative CPU power of the group */
2284 avg_load = sg_div_cpu_power(group,
2285 avg_load * SCHED_LOAD_SCALE);
2288 this_load = avg_load;
2290 } else if (avg_load < min_load) {
2291 min_load = avg_load;
2294 } while (group = group->next, group != sd->groups);
2296 if (!idlest || 100*this_load < imbalance*min_load)
2302 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2305 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
2307 unsigned long load, min_load = ULONG_MAX;
2311 /* Traverse only the allowed CPUs */
2312 for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {
2313 load = weighted_cpuload(i);
2315 if (load < min_load || (load == min_load && i == this_cpu)) {
2325 * sched_balance_self: balance the current task (running on cpu) in domains
2326 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2329 * Balance, ie. select the least loaded group.
2331 * Returns the target CPU number, or the same CPU if no balancing is needed.
2333 * preempt must be disabled.
2335 static int sched_balance_self(int cpu, int flag)
2337 struct task_struct *t = current;
2338 struct sched_domain *tmp, *sd = NULL;
2340 for_each_domain(cpu, tmp) {
2342 * If power savings logic is enabled for a domain, stop there.
2344 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2346 if (tmp->flags & flag)
2354 struct sched_group *group;
2355 int new_cpu, weight;
2357 if (!(sd->flags & flag)) {
2362 group = find_idlest_group(sd, t, cpu);
2368 new_cpu = find_idlest_cpu(group, t, cpu);
2369 if (new_cpu == -1 || new_cpu == cpu) {
2370 /* Now try balancing at a lower domain level of cpu */
2375 /* Now try balancing at a lower domain level of new_cpu */
2377 weight = cpumask_weight(sched_domain_span(sd));
2379 for_each_domain(cpu, tmp) {
2380 if (weight <= cpumask_weight(sched_domain_span(tmp)))
2382 if (tmp->flags & flag)
2385 /* while loop will break here if sd == NULL */
2391 #endif /* CONFIG_SMP */
2394 * task_oncpu_function_call - call a function on the cpu on which a task runs
2395 * @p: the task to evaluate
2396 * @func: the function to be called
2397 * @info: the function call argument
2399 * Calls the function @func when the task is currently running. This might
2400 * be on the current CPU, which just calls the function directly
2402 void task_oncpu_function_call(struct task_struct *p,
2403 void (*func) (void *info), void *info)
2410 smp_call_function_single(cpu, func, info, 1);
2415 * try_to_wake_up - wake up a thread
2416 * @p: the to-be-woken-up thread
2417 * @state: the mask of task states that can be woken
2418 * @sync: do a synchronous wakeup?
2420 * Put it on the run-queue if it's not already there. The "current"
2421 * thread is always on the run-queue (except when the actual
2422 * re-schedule is in progress), and as such you're allowed to do
2423 * the simpler "current->state = TASK_RUNNING" to mark yourself
2424 * runnable without the overhead of this.
2426 * returns failure only if the task is already active.
2428 static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
2430 int cpu, orig_cpu, this_cpu, success = 0;
2431 unsigned long flags;
2435 if (!sched_feat(SYNC_WAKEUPS))
2439 if (sched_feat(LB_WAKEUP_UPDATE) && !root_task_group_empty()) {
2440 struct sched_domain *sd;
2442 this_cpu = raw_smp_processor_id();
2445 for_each_domain(this_cpu, sd) {
2446 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2455 rq = task_rq_lock(p, &flags);
2456 update_rq_clock(rq);
2457 old_state = p->state;
2458 if (!(old_state & state))
2466 this_cpu = smp_processor_id();
2469 if (unlikely(task_running(rq, p)))
2472 cpu = p->sched_class->select_task_rq(p, sync);
2473 if (cpu != orig_cpu) {
2474 set_task_cpu(p, cpu);
2475 task_rq_unlock(rq, &flags);
2476 /* might preempt at this point */
2477 rq = task_rq_lock(p, &flags);
2478 old_state = p->state;
2479 if (!(old_state & state))
2484 this_cpu = smp_processor_id();
2488 #ifdef CONFIG_SCHEDSTATS
2489 schedstat_inc(rq, ttwu_count);
2490 if (cpu == this_cpu)
2491 schedstat_inc(rq, ttwu_local);
2493 struct sched_domain *sd;
2494 for_each_domain(this_cpu, sd) {
2495 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2496 schedstat_inc(sd, ttwu_wake_remote);
2501 #endif /* CONFIG_SCHEDSTATS */
2504 #endif /* CONFIG_SMP */
2505 schedstat_inc(p, se.nr_wakeups);
2507 schedstat_inc(p, se.nr_wakeups_sync);
2508 if (orig_cpu != cpu)
2509 schedstat_inc(p, se.nr_wakeups_migrate);
2510 if (cpu == this_cpu)
2511 schedstat_inc(p, se.nr_wakeups_local);
2513 schedstat_inc(p, se.nr_wakeups_remote);
2514 activate_task(rq, p, 1);
2518 * Only attribute actual wakeups done by this task.
2520 if (!in_interrupt()) {
2521 struct sched_entity *se = ¤t->se;
2522 u64 sample = se->sum_exec_runtime;
2524 if (se->last_wakeup)
2525 sample -= se->last_wakeup;
2527 sample -= se->start_runtime;
2528 update_avg(&se->avg_wakeup, sample);
2530 se->last_wakeup = se->sum_exec_runtime;
2534 trace_sched_wakeup(rq, p, success);
2535 check_preempt_curr(rq, p, sync);
2537 p->state = TASK_RUNNING;
2539 if (p->sched_class->task_wake_up)
2540 p->sched_class->task_wake_up(rq, p);
2543 task_rq_unlock(rq, &flags);
2549 * wake_up_process - Wake up a specific process
2550 * @p: The process to be woken up.
2552 * Attempt to wake up the nominated process and move it to the set of runnable
2553 * processes. Returns 1 if the process was woken up, 0 if it was already
2556 * It may be assumed that this function implies a write memory barrier before
2557 * changing the task state if and only if any tasks are woken up.
2559 int wake_up_process(struct task_struct *p)
2561 return try_to_wake_up(p, TASK_ALL, 0);
2563 EXPORT_SYMBOL(wake_up_process);
2565 int wake_up_state(struct task_struct *p, unsigned int state)
2567 return try_to_wake_up(p, state, 0);
2571 * Perform scheduler related setup for a newly forked process p.
2572 * p is forked by current.
2574 * __sched_fork() is basic setup used by init_idle() too:
2576 static void __sched_fork(struct task_struct *p)
2578 p->se.exec_start = 0;
2579 p->se.sum_exec_runtime = 0;
2580 p->se.prev_sum_exec_runtime = 0;
2581 p->se.nr_migrations = 0;
2582 p->se.last_wakeup = 0;
2583 p->se.avg_overlap = 0;
2584 p->se.start_runtime = 0;
2585 p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
2587 #ifdef CONFIG_SCHEDSTATS
2588 p->se.wait_start = 0;
2590 p->se.wait_count = 0;
2593 p->se.sleep_start = 0;
2594 p->se.sleep_max = 0;
2595 p->se.sum_sleep_runtime = 0;
2597 p->se.block_start = 0;
2598 p->se.block_max = 0;
2600 p->se.slice_max = 0;
2602 p->se.nr_migrations_cold = 0;
2603 p->se.nr_failed_migrations_affine = 0;
2604 p->se.nr_failed_migrations_running = 0;
2605 p->se.nr_failed_migrations_hot = 0;
2606 p->se.nr_forced_migrations = 0;
2607 p->se.nr_forced2_migrations = 0;
2609 p->se.nr_wakeups = 0;
2610 p->se.nr_wakeups_sync = 0;
2611 p->se.nr_wakeups_migrate = 0;
2612 p->se.nr_wakeups_local = 0;
2613 p->se.nr_wakeups_remote = 0;
2614 p->se.nr_wakeups_affine = 0;
2615 p->se.nr_wakeups_affine_attempts = 0;
2616 p->se.nr_wakeups_passive = 0;
2617 p->se.nr_wakeups_idle = 0;
2621 INIT_LIST_HEAD(&p->rt.run_list);
2623 INIT_LIST_HEAD(&p->se.group_node);
2625 #ifdef CONFIG_PREEMPT_NOTIFIERS
2626 INIT_HLIST_HEAD(&p->preempt_notifiers);
2630 * We mark the process as running here, but have not actually
2631 * inserted it onto the runqueue yet. This guarantees that
2632 * nobody will actually run it, and a signal or other external
2633 * event cannot wake it up and insert it on the runqueue either.
2635 p->state = TASK_RUNNING;
2639 * fork()/clone()-time setup:
2641 void sched_fork(struct task_struct *p, int clone_flags)
2643 int cpu = get_cpu();
2648 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
2650 set_task_cpu(p, cpu);
2653 * Make sure we do not leak PI boosting priority to the child.
2655 p->prio = current->normal_prio;
2658 * Revert to default priority/policy on fork if requested.
2660 if (unlikely(p->sched_reset_on_fork)) {
2661 if (p->policy == SCHED_FIFO || p->policy == SCHED_RR)
2662 p->policy = SCHED_NORMAL;
2664 if (p->normal_prio < DEFAULT_PRIO)
2665 p->prio = DEFAULT_PRIO;
2667 if (PRIO_TO_NICE(p->static_prio) < 0) {
2668 p->static_prio = NICE_TO_PRIO(0);
2673 * We don't need the reset flag anymore after the fork. It has
2674 * fulfilled its duty:
2676 p->sched_reset_on_fork = 0;
2679 if (!rt_prio(p->prio))
2680 p->sched_class = &fair_sched_class;
2682 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2683 if (likely(sched_info_on()))
2684 memset(&p->sched_info, 0, sizeof(p->sched_info));
2686 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2689 #ifdef CONFIG_PREEMPT
2690 /* Want to start with kernel preemption disabled. */
2691 task_thread_info(p)->preempt_count = 1;
2693 plist_node_init(&p->pushable_tasks, MAX_PRIO);
2699 * wake_up_new_task - wake up a newly created task for the first time.
2701 * This function will do some initial scheduler statistics housekeeping
2702 * that must be done for every newly created context, then puts the task
2703 * on the runqueue and wakes it.
2705 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2707 unsigned long flags;
2710 rq = task_rq_lock(p, &flags);
2711 BUG_ON(p->state != TASK_RUNNING);
2712 update_rq_clock(rq);
2714 p->prio = effective_prio(p);
2716 if (!p->sched_class->task_new || !current->se.on_rq) {
2717 activate_task(rq, p, 0);
2720 * Let the scheduling class do new task startup
2721 * management (if any):
2723 p->sched_class->task_new(rq, p);
2726 trace_sched_wakeup_new(rq, p, 1);
2727 check_preempt_curr(rq, p, 0);
2729 if (p->sched_class->task_wake_up)
2730 p->sched_class->task_wake_up(rq, p);
2732 task_rq_unlock(rq, &flags);
2735 #ifdef CONFIG_PREEMPT_NOTIFIERS
2738 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2739 * @notifier: notifier struct to register
2741 void preempt_notifier_register(struct preempt_notifier *notifier)
2743 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2745 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2748 * preempt_notifier_unregister - no longer interested in preemption notifications
2749 * @notifier: notifier struct to unregister
2751 * This is safe to call from within a preemption notifier.
2753 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2755 hlist_del(¬ifier->link);
2757 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2759 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2761 struct preempt_notifier *notifier;
2762 struct hlist_node *node;
2764 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2765 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2769 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2770 struct task_struct *next)
2772 struct preempt_notifier *notifier;
2773 struct hlist_node *node;
2775 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2776 notifier->ops->sched_out(notifier, next);
2779 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2781 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2786 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2787 struct task_struct *next)
2791 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2794 * prepare_task_switch - prepare to switch tasks
2795 * @rq: the runqueue preparing to switch
2796 * @prev: the current task that is being switched out
2797 * @next: the task we are going to switch to.
2799 * This is called with the rq lock held and interrupts off. It must
2800 * be paired with a subsequent finish_task_switch after the context
2803 * prepare_task_switch sets up locking and calls architecture specific
2807 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2808 struct task_struct *next)
2810 fire_sched_out_preempt_notifiers(prev, next);
2811 prepare_lock_switch(rq, next);
2812 prepare_arch_switch(next);
2816 * finish_task_switch - clean up after a task-switch
2817 * @rq: runqueue associated with task-switch
2818 * @prev: the thread we just switched away from.
2820 * finish_task_switch must be called after the context switch, paired
2821 * with a prepare_task_switch call before the context switch.
2822 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2823 * and do any other architecture-specific cleanup actions.
2825 * Note that we may have delayed dropping an mm in context_switch(). If
2826 * so, we finish that here outside of the runqueue lock. (Doing it
2827 * with the lock held can cause deadlocks; see schedule() for
2830 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2831 __releases(rq->lock)
2833 struct mm_struct *mm = rq->prev_mm;
2836 int post_schedule = 0;
2838 if (current->sched_class->needs_post_schedule)
2839 post_schedule = current->sched_class->needs_post_schedule(rq);
2845 * A task struct has one reference for the use as "current".
2846 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2847 * schedule one last time. The schedule call will never return, and
2848 * the scheduled task must drop that reference.
2849 * The test for TASK_DEAD must occur while the runqueue locks are
2850 * still held, otherwise prev could be scheduled on another cpu, die
2851 * there before we look at prev->state, and then the reference would
2853 * Manfred Spraul <manfred@colorfullife.com>
2855 prev_state = prev->state;
2856 finish_arch_switch(prev);
2857 perf_counter_task_sched_in(current, cpu_of(rq));
2858 finish_lock_switch(rq, prev);
2861 current->sched_class->post_schedule(rq);
2864 fire_sched_in_preempt_notifiers(current);
2867 if (unlikely(prev_state == TASK_DEAD)) {
2869 * Remove function-return probe instances associated with this
2870 * task and put them back on the free list.
2872 kprobe_flush_task(prev);
2873 put_task_struct(prev);
2878 * schedule_tail - first thing a freshly forked thread must call.
2879 * @prev: the thread we just switched away from.
2881 asmlinkage void schedule_tail(struct task_struct *prev)
2882 __releases(rq->lock)
2884 struct rq *rq = this_rq();
2886 finish_task_switch(rq, prev);
2887 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2888 /* In this case, finish_task_switch does not reenable preemption */
2891 if (current->set_child_tid)
2892 put_user(task_pid_vnr(current), current->set_child_tid);
2896 * context_switch - switch to the new MM and the new
2897 * thread's register state.
2900 context_switch(struct rq *rq, struct task_struct *prev,
2901 struct task_struct *next)
2903 struct mm_struct *mm, *oldmm;
2905 prepare_task_switch(rq, prev, next);
2906 trace_sched_switch(rq, prev, next);
2908 oldmm = prev->active_mm;
2910 * For paravirt, this is coupled with an exit in switch_to to
2911 * combine the page table reload and the switch backend into
2914 arch_start_context_switch(prev);
2916 if (unlikely(!mm)) {
2917 next->active_mm = oldmm;
2918 atomic_inc(&oldmm->mm_count);
2919 enter_lazy_tlb(oldmm, next);
2921 switch_mm(oldmm, mm, next);
2923 if (unlikely(!prev->mm)) {
2924 prev->active_mm = NULL;
2925 rq->prev_mm = oldmm;
2928 * Since the runqueue lock will be released by the next
2929 * task (which is an invalid locking op but in the case
2930 * of the scheduler it's an obvious special-case), so we
2931 * do an early lockdep release here:
2933 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2934 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2937 /* Here we just switch the register state and the stack. */
2938 switch_to(prev, next, prev);
2942 * this_rq must be evaluated again because prev may have moved
2943 * CPUs since it called schedule(), thus the 'rq' on its stack
2944 * frame will be invalid.
2946 finish_task_switch(this_rq(), prev);
2950 * nr_running, nr_uninterruptible and nr_context_switches:
2952 * externally visible scheduler statistics: current number of runnable
2953 * threads, current number of uninterruptible-sleeping threads, total
2954 * number of context switches performed since bootup.
2956 unsigned long nr_running(void)
2958 unsigned long i, sum = 0;
2960 for_each_online_cpu(i)
2961 sum += cpu_rq(i)->nr_running;
2966 unsigned long nr_uninterruptible(void)
2968 unsigned long i, sum = 0;
2970 for_each_possible_cpu(i)
2971 sum += cpu_rq(i)->nr_uninterruptible;
2974 * Since we read the counters lockless, it might be slightly
2975 * inaccurate. Do not allow it to go below zero though:
2977 if (unlikely((long)sum < 0))
2983 unsigned long long nr_context_switches(void)
2986 unsigned long long sum = 0;
2988 for_each_possible_cpu(i)
2989 sum += cpu_rq(i)->nr_switches;
2994 unsigned long nr_iowait(void)
2996 unsigned long i, sum = 0;
2998 for_each_possible_cpu(i)
2999 sum += atomic_read(&cpu_rq(i)->nr_iowait);
3004 /* Variables and functions for calc_load */
3005 static atomic_long_t calc_load_tasks;
3006 static unsigned long calc_load_update;
3007 unsigned long avenrun[3];
3008 EXPORT_SYMBOL(avenrun);
3011 * get_avenrun - get the load average array
3012 * @loads: pointer to dest load array
3013 * @offset: offset to add
3014 * @shift: shift count to shift the result left
3016 * These values are estimates at best, so no need for locking.
3018 void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
3020 loads[0] = (avenrun[0] + offset) << shift;
3021 loads[1] = (avenrun[1] + offset) << shift;
3022 loads[2] = (avenrun[2] + offset) << shift;
3025 static unsigned long
3026 calc_load(unsigned long load, unsigned long exp, unsigned long active)
3029 load += active * (FIXED_1 - exp);
3030 return load >> FSHIFT;
3034 * calc_load - update the avenrun load estimates 10 ticks after the
3035 * CPUs have updated calc_load_tasks.
3037 void calc_global_load(void)
3039 unsigned long upd = calc_load_update + 10;
3042 if (time_before(jiffies, upd))
3045 active = atomic_long_read(&calc_load_tasks);
3046 active = active > 0 ? active * FIXED_1 : 0;
3048 avenrun[0] = calc_load(avenrun[0], EXP_1, active);
3049 avenrun[1] = calc_load(avenrun[1], EXP_5, active);
3050 avenrun[2] = calc_load(avenrun[2], EXP_15, active);
3052 calc_load_update += LOAD_FREQ;
3056 * Either called from update_cpu_load() or from a cpu going idle
3058 static void calc_load_account_active(struct rq *this_rq)
3060 long nr_active, delta;
3062 nr_active = this_rq->nr_running;
3063 nr_active += (long) this_rq->nr_uninterruptible;
3065 if (nr_active != this_rq->calc_load_active) {
3066 delta = nr_active - this_rq->calc_load_active;
3067 this_rq->calc_load_active = nr_active;
3068 atomic_long_add(delta, &calc_load_tasks);
3073 * Externally visible per-cpu scheduler statistics:
3074 * cpu_nr_migrations(cpu) - number of migrations into that cpu
3076 u64 cpu_nr_migrations(int cpu)
3078 return cpu_rq(cpu)->nr_migrations_in;
3082 * Update rq->cpu_load[] statistics. This function is usually called every
3083 * scheduler tick (TICK_NSEC).
3085 static void update_cpu_load(struct rq *this_rq)
3087 unsigned long this_load = this_rq->load.weight;
3090 this_rq->nr_load_updates++;
3092 /* Update our load: */
3093 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
3094 unsigned long old_load, new_load;
3096 /* scale is effectively 1 << i now, and >> i divides by scale */
3098 old_load = this_rq->cpu_load[i];
3099 new_load = this_load;
3101 * Round up the averaging division if load is increasing. This
3102 * prevents us from getting stuck on 9 if the load is 10, for
3105 if (new_load > old_load)
3106 new_load += scale-1;
3107 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
3110 if (time_after_eq(jiffies, this_rq->calc_load_update)) {
3111 this_rq->calc_load_update += LOAD_FREQ;
3112 calc_load_account_active(this_rq);
3119 * double_rq_lock - safely lock two runqueues
3121 * Note this does not disable interrupts like task_rq_lock,
3122 * you need to do so manually before calling.
3124 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
3125 __acquires(rq1->lock)
3126 __acquires(rq2->lock)
3128 BUG_ON(!irqs_disabled());
3130 spin_lock(&rq1->lock);
3131 __acquire(rq2->lock); /* Fake it out ;) */
3134 spin_lock(&rq1->lock);
3135 spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
3137 spin_lock(&rq2->lock);
3138 spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
3141 update_rq_clock(rq1);
3142 update_rq_clock(rq2);
3146 * double_rq_unlock - safely unlock two runqueues
3148 * Note this does not restore interrupts like task_rq_unlock,
3149 * you need to do so manually after calling.
3151 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
3152 __releases(rq1->lock)
3153 __releases(rq2->lock)
3155 spin_unlock(&rq1->lock);
3157 spin_unlock(&rq2->lock);
3159 __release(rq2->lock);
3163 * If dest_cpu is allowed for this process, migrate the task to it.
3164 * This is accomplished by forcing the cpu_allowed mask to only
3165 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
3166 * the cpu_allowed mask is restored.
3168 static void sched_migrate_task(struct task_struct *p, int dest_cpu)
3170 struct migration_req req;
3171 unsigned long flags;
3174 rq = task_rq_lock(p, &flags);
3175 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)
3176 || unlikely(!cpu_active(dest_cpu)))
3179 /* force the process onto the specified CPU */
3180 if (migrate_task(p, dest_cpu, &req)) {
3181 /* Need to wait for migration thread (might exit: take ref). */
3182 struct task_struct *mt = rq->migration_thread;
3184 get_task_struct(mt);
3185 task_rq_unlock(rq, &flags);
3186 wake_up_process(mt);
3187 put_task_struct(mt);
3188 wait_for_completion(&req.done);
3193 task_rq_unlock(rq, &flags);
3197 * sched_exec - execve() is a valuable balancing opportunity, because at
3198 * this point the task has the smallest effective memory and cache footprint.
3200 void sched_exec(void)
3202 int new_cpu, this_cpu = get_cpu();
3203 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
3205 if (new_cpu != this_cpu)
3206 sched_migrate_task(current, new_cpu);
3210 * pull_task - move a task from a remote runqueue to the local runqueue.
3211 * Both runqueues must be locked.
3213 static void pull_task(struct rq *src_rq, struct task_struct *p,
3214 struct rq *this_rq, int this_cpu)
3216 deactivate_task(src_rq, p, 0);
3217 set_task_cpu(p, this_cpu);
3218 activate_task(this_rq, p, 0);
3220 * Note that idle threads have a prio of MAX_PRIO, for this test
3221 * to be always true for them.
3223 check_preempt_curr(this_rq, p, 0);
3227 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3230 int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
3231 struct sched_domain *sd, enum cpu_idle_type idle,
3234 int tsk_cache_hot = 0;
3236 * We do not migrate tasks that are:
3237 * 1) running (obviously), or
3238 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3239 * 3) are cache-hot on their current CPU.
3241 if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) {
3242 schedstat_inc(p, se.nr_failed_migrations_affine);
3247 if (task_running(rq, p)) {
3248 schedstat_inc(p, se.nr_failed_migrations_running);
3253 * Aggressive migration if:
3254 * 1) task is cache cold, or
3255 * 2) too many balance attempts have failed.
3258 tsk_cache_hot = task_hot(p, rq->clock, sd);
3259 if (!tsk_cache_hot ||
3260 sd->nr_balance_failed > sd->cache_nice_tries) {
3261 #ifdef CONFIG_SCHEDSTATS
3262 if (tsk_cache_hot) {
3263 schedstat_inc(sd, lb_hot_gained[idle]);
3264 schedstat_inc(p, se.nr_forced_migrations);
3270 if (tsk_cache_hot) {
3271 schedstat_inc(p, se.nr_failed_migrations_hot);
3277 static unsigned long
3278 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3279 unsigned long max_load_move, struct sched_domain *sd,
3280 enum cpu_idle_type idle, int *all_pinned,
3281 int *this_best_prio, struct rq_iterator *iterator)
3283 int loops = 0, pulled = 0, pinned = 0;
3284 struct task_struct *p;
3285 long rem_load_move = max_load_move;
3287 if (max_load_move == 0)
3293 * Start the load-balancing iterator:
3295 p = iterator->start(iterator->arg);
3297 if (!p || loops++ > sysctl_sched_nr_migrate)
3300 if ((p->se.load.weight >> 1) > rem_load_move ||
3301 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3302 p = iterator->next(iterator->arg);
3306 pull_task(busiest, p, this_rq, this_cpu);
3308 rem_load_move -= p->se.load.weight;
3310 #ifdef CONFIG_PREEMPT
3312 * NEWIDLE balancing is a source of latency, so preemptible kernels
3313 * will stop after the first task is pulled to minimize the critical
3316 if (idle == CPU_NEWLY_IDLE)
3321 * We only want to steal up to the prescribed amount of weighted load.
3323 if (rem_load_move > 0) {
3324 if (p->prio < *this_best_prio)
3325 *this_best_prio = p->prio;
3326 p = iterator->next(iterator->arg);
3331 * Right now, this is one of only two places pull_task() is called,
3332 * so we can safely collect pull_task() stats here rather than
3333 * inside pull_task().
3335 schedstat_add(sd, lb_gained[idle], pulled);
3338 *all_pinned = pinned;
3340 return max_load_move - rem_load_move;
3344 * move_tasks tries to move up to max_load_move weighted load from busiest to
3345 * this_rq, as part of a balancing operation within domain "sd".
3346 * Returns 1 if successful and 0 otherwise.
3348 * Called with both runqueues locked.
3350 static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3351 unsigned long max_load_move,
3352 struct sched_domain *sd, enum cpu_idle_type idle,
3355 const struct sched_class *class = sched_class_highest;
3356 unsigned long total_load_moved = 0;
3357 int this_best_prio = this_rq->curr->prio;
3361 class->load_balance(this_rq, this_cpu, busiest,
3362 max_load_move - total_load_moved,
3363 sd, idle, all_pinned, &this_best_prio);
3364 class = class->next;
3366 #ifdef CONFIG_PREEMPT
3368 * NEWIDLE balancing is a source of latency, so preemptible
3369 * kernels will stop after the first task is pulled to minimize
3370 * the critical section.
3372 if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
3375 } while (class && max_load_move > total_load_moved);
3377 return total_load_moved > 0;
3381 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3382 struct sched_domain *sd, enum cpu_idle_type idle,
3383 struct rq_iterator *iterator)
3385 struct task_struct *p = iterator->start(iterator->arg);
3389 if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3390 pull_task(busiest, p, this_rq, this_cpu);
3392 * Right now, this is only the second place pull_task()
3393 * is called, so we can safely collect pull_task()
3394 * stats here rather than inside pull_task().
3396 schedstat_inc(sd, lb_gained[idle]);
3400 p = iterator->next(iterator->arg);
3407 * move_one_task tries to move exactly one task from busiest to this_rq, as
3408 * part of active balancing operations within "domain".
3409 * Returns 1 if successful and 0 otherwise.
3411 * Called with both runqueues locked.
3413 static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3414 struct sched_domain *sd, enum cpu_idle_type idle)
3416 const struct sched_class *class;
3418 for (class = sched_class_highest; class; class = class->next)
3419 if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
3424 /********** Helpers for find_busiest_group ************************/
3426 * sd_lb_stats - Structure to store the statistics of a sched_domain
3427 * during load balancing.
3429 struct sd_lb_stats {
3430 struct sched_group *busiest; /* Busiest group in this sd */
3431 struct sched_group *this; /* Local group in this sd */
3432 unsigned long total_load; /* Total load of all groups in sd */
3433 unsigned long total_pwr; /* Total power of all groups in sd */
3434 unsigned long avg_load; /* Average load across all groups in sd */
3436 /** Statistics of this group */
3437 unsigned long this_load;
3438 unsigned long this_load_per_task;
3439 unsigned long this_nr_running;
3441 /* Statistics of the busiest group */
3442 unsigned long max_load;
3443 unsigned long busiest_load_per_task;
3444 unsigned long busiest_nr_running;
3446 int group_imb; /* Is there imbalance in this sd */
3447 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3448 int power_savings_balance; /* Is powersave balance needed for this sd */
3449 struct sched_group *group_min; /* Least loaded group in sd */
3450 struct sched_group *group_leader; /* Group which relieves group_min */
3451 unsigned long min_load_per_task; /* load_per_task in group_min */
3452 unsigned long leader_nr_running; /* Nr running of group_leader */
3453 unsigned long min_nr_running; /* Nr running of group_min */
3458 * sg_lb_stats - stats of a sched_group required for load_balancing
3460 struct sg_lb_stats {
3461 unsigned long avg_load; /*Avg load across the CPUs of the group */
3462 unsigned long group_load; /* Total load over the CPUs of the group */
3463 unsigned long sum_nr_running; /* Nr tasks running in the group */
3464 unsigned long sum_weighted_load; /* Weighted load of group's tasks */
3465 unsigned long group_capacity;
3466 int group_imb; /* Is there an imbalance in the group ? */
3470 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3471 * @group: The group whose first cpu is to be returned.
3473 static inline unsigned int group_first_cpu(struct sched_group *group)
3475 return cpumask_first(sched_group_cpus(group));
3479 * get_sd_load_idx - Obtain the load index for a given sched domain.
3480 * @sd: The sched_domain whose load_idx is to be obtained.
3481 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3483 static inline int get_sd_load_idx(struct sched_domain *sd,
3484 enum cpu_idle_type idle)
3490 load_idx = sd->busy_idx;
3493 case CPU_NEWLY_IDLE:
3494 load_idx = sd->newidle_idx;
3497 load_idx = sd->idle_idx;
3505 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3507 * init_sd_power_savings_stats - Initialize power savings statistics for
3508 * the given sched_domain, during load balancing.
3510 * @sd: Sched domain whose power-savings statistics are to be initialized.
3511 * @sds: Variable containing the statistics for sd.
3512 * @idle: Idle status of the CPU at which we're performing load-balancing.
3514 static inline void init_sd_power_savings_stats(struct sched_domain *sd,
3515 struct sd_lb_stats *sds, enum cpu_idle_type idle)
3518 * Busy processors will not participate in power savings
3521 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
3522 sds->power_savings_balance = 0;
3524 sds->power_savings_balance = 1;
3525 sds->min_nr_running = ULONG_MAX;
3526 sds->leader_nr_running = 0;
3531 * update_sd_power_savings_stats - Update the power saving stats for a
3532 * sched_domain while performing load balancing.
3534 * @group: sched_group belonging to the sched_domain under consideration.
3535 * @sds: Variable containing the statistics of the sched_domain
3536 * @local_group: Does group contain the CPU for which we're performing
3538 * @sgs: Variable containing the statistics of the group.
3540 static inline void update_sd_power_savings_stats(struct sched_group *group,
3541 struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
3544 if (!sds->power_savings_balance)
3548 * If the local group is idle or completely loaded
3549 * no need to do power savings balance at this domain
3551 if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
3552 !sds->this_nr_running))
3553 sds->power_savings_balance = 0;
3556 * If a group is already running at full capacity or idle,
3557 * don't include that group in power savings calculations
3559 if (!sds->power_savings_balance ||
3560 sgs->sum_nr_running >= sgs->group_capacity ||
3561 !sgs->sum_nr_running)
3565 * Calculate the group which has the least non-idle load.
3566 * This is the group from where we need to pick up the load
3569 if ((sgs->sum_nr_running < sds->min_nr_running) ||
3570 (sgs->sum_nr_running == sds->min_nr_running &&
3571 group_first_cpu(group) > group_first_cpu(sds->group_min))) {
3572 sds->group_min = group;
3573 sds->min_nr_running = sgs->sum_nr_running;
3574 sds->min_load_per_task = sgs->sum_weighted_load /
3575 sgs->sum_nr_running;
3579 * Calculate the group which is almost near its
3580 * capacity but still has some space to pick up some load
3581 * from other group and save more power
3583 if (sgs->sum_nr_running > sgs->group_capacity - 1)
3586 if (sgs->sum_nr_running > sds->leader_nr_running ||
3587 (sgs->sum_nr_running == sds->leader_nr_running &&
3588 group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
3589 sds->group_leader = group;
3590 sds->leader_nr_running = sgs->sum_nr_running;
3595 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3596 * @sds: Variable containing the statistics of the sched_domain
3597 * under consideration.
3598 * @this_cpu: Cpu at which we're currently performing load-balancing.
3599 * @imbalance: Variable to store the imbalance.
3602 * Check if we have potential to perform some power-savings balance.
3603 * If yes, set the busiest group to be the least loaded group in the
3604 * sched_domain, so that it's CPUs can be put to idle.
3606 * Returns 1 if there is potential to perform power-savings balance.
3609 static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
3610 int this_cpu, unsigned long *imbalance)
3612 if (!sds->power_savings_balance)
3615 if (sds->this != sds->group_leader ||
3616 sds->group_leader == sds->group_min)
3619 *imbalance = sds->min_load_per_task;
3620 sds->busiest = sds->group_min;
3622 if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
3623 cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
3624 group_first_cpu(sds->group_leader);
3630 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3631 static inline void init_sd_power_savings_stats(struct sched_domain *sd,
3632 struct sd_lb_stats *sds, enum cpu_idle_type idle)
3637 static inline void update_sd_power_savings_stats(struct sched_group *group,
3638 struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
3643 static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
3644 int this_cpu, unsigned long *imbalance)
3648 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3652 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3653 * @group: sched_group whose statistics are to be updated.
3654 * @this_cpu: Cpu for which load balance is currently performed.
3655 * @idle: Idle status of this_cpu
3656 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3657 * @sd_idle: Idle status of the sched_domain containing group.
3658 * @local_group: Does group contain this_cpu.
3659 * @cpus: Set of cpus considered for load balancing.
3660 * @balance: Should we balance.
3661 * @sgs: variable to hold the statistics for this group.
3663 static inline void update_sg_lb_stats(struct sched_group *group, int this_cpu,
3664 enum cpu_idle_type idle, int load_idx, int *sd_idle,
3665 int local_group, const struct cpumask *cpus,
3666 int *balance, struct sg_lb_stats *sgs)
3668 unsigned long load, max_cpu_load, min_cpu_load;
3670 unsigned int balance_cpu = -1, first_idle_cpu = 0;
3671 unsigned long sum_avg_load_per_task;
3672 unsigned long avg_load_per_task;
3675 balance_cpu = group_first_cpu(group);
3677 /* Tally up the load of all CPUs in the group */
3678 sum_avg_load_per_task = avg_load_per_task = 0;
3680 min_cpu_load = ~0UL;
3682 for_each_cpu_and(i, sched_group_cpus(group), cpus) {
3683 struct rq *rq = cpu_rq(i);
3685 if (*sd_idle && rq->nr_running)
3688 /* Bias balancing toward cpus of our domain */
3690 if (idle_cpu(i) && !first_idle_cpu) {
3695 load = target_load(i, load_idx);
3697 load = source_load(i, load_idx);
3698 if (load > max_cpu_load)
3699 max_cpu_load = load;
3700 if (min_cpu_load > load)
3701 min_cpu_load = load;
3704 sgs->group_load += load;
3705 sgs->sum_nr_running += rq->nr_running;
3706 sgs->sum_weighted_load += weighted_cpuload(i);
3708 sum_avg_load_per_task += cpu_avg_load_per_task(i);
3712 * First idle cpu or the first cpu(busiest) in this sched group
3713 * is eligible for doing load balancing at this and above
3714 * domains. In the newly idle case, we will allow all the cpu's
3715 * to do the newly idle load balance.
3717 if (idle != CPU_NEWLY_IDLE && local_group &&
3718 balance_cpu != this_cpu && balance) {
3723 /* Adjust by relative CPU power of the group */
3724 sgs->avg_load = sg_div_cpu_power(group,
3725 sgs->group_load * SCHED_LOAD_SCALE);
3729 * Consider the group unbalanced when the imbalance is larger
3730 * than the average weight of two tasks.
3732 * APZ: with cgroup the avg task weight can vary wildly and
3733 * might not be a suitable number - should we keep a
3734 * normalized nr_running number somewhere that negates
3737 avg_load_per_task = sg_div_cpu_power(group,
3738 sum_avg_load_per_task * SCHED_LOAD_SCALE);
3740 if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
3743 sgs->group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
3748 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3749 * @sd: sched_domain whose statistics are to be updated.
3750 * @this_cpu: Cpu for which load balance is currently performed.
3751 * @idle: Idle status of this_cpu
3752 * @sd_idle: Idle status of the sched_domain containing group.
3753 * @cpus: Set of cpus considered for load balancing.
3754 * @balance: Should we balance.
3755 * @sds: variable to hold the statistics for this sched_domain.
3757 static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
3758 enum cpu_idle_type idle, int *sd_idle,
3759 const struct cpumask *cpus, int *balance,
3760 struct sd_lb_stats *sds)
3762 struct sched_group *group = sd->groups;
3763 struct sg_lb_stats sgs;
3766 init_sd_power_savings_stats(sd, sds, idle);
3767 load_idx = get_sd_load_idx(sd, idle);
3772 local_group = cpumask_test_cpu(this_cpu,
3773 sched_group_cpus(group));
3774 memset(&sgs, 0, sizeof(sgs));
3775 update_sg_lb_stats(group, this_cpu, idle, load_idx, sd_idle,
3776 local_group, cpus, balance, &sgs);
3778 if (local_group && balance && !(*balance))
3781 sds->total_load += sgs.group_load;
3782 sds->total_pwr += group->__cpu_power;
3785 sds->this_load = sgs.avg_load;
3787 sds->this_nr_running = sgs.sum_nr_running;
3788 sds->this_load_per_task = sgs.sum_weighted_load;
3789 } else if (sgs.avg_load > sds->max_load &&
3790 (sgs.sum_nr_running > sgs.group_capacity ||
3792 sds->max_load = sgs.avg_load;
3793 sds->busiest = group;
3794 sds->busiest_nr_running = sgs.sum_nr_running;
3795 sds->busiest_load_per_task = sgs.sum_weighted_load;
3796 sds->group_imb = sgs.group_imb;
3799 update_sd_power_savings_stats(group, sds, local_group, &sgs);
3800 group = group->next;
3801 } while (group != sd->groups);
3806 * fix_small_imbalance - Calculate the minor imbalance that exists
3807 * amongst the groups of a sched_domain, during
3809 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3810 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3811 * @imbalance: Variable to store the imbalance.
3813 static inline void fix_small_imbalance(struct sd_lb_stats *sds,
3814 int this_cpu, unsigned long *imbalance)
3816 unsigned long tmp, pwr_now = 0, pwr_move = 0;
3817 unsigned int imbn = 2;
3819 if (sds->this_nr_running) {
3820 sds->this_load_per_task /= sds->this_nr_running;
3821 if (sds->busiest_load_per_task >
3822 sds->this_load_per_task)
3825 sds->this_load_per_task =
3826 cpu_avg_load_per_task(this_cpu);
3828 if (sds->max_load - sds->this_load + sds->busiest_load_per_task >=
3829 sds->busiest_load_per_task * imbn) {
3830 *imbalance = sds->busiest_load_per_task;
3835 * OK, we don't have enough imbalance to justify moving tasks,
3836 * however we may be able to increase total CPU power used by
3840 pwr_now += sds->busiest->__cpu_power *
3841 min(sds->busiest_load_per_task, sds->max_load);
3842 pwr_now += sds->this->__cpu_power *
3843 min(sds->this_load_per_task, sds->this_load);
3844 pwr_now /= SCHED_LOAD_SCALE;
3846 /* Amount of load we'd subtract */
3847 tmp = sg_div_cpu_power(sds->busiest,
3848 sds->busiest_load_per_task * SCHED_LOAD_SCALE);
3849 if (sds->max_load > tmp)
3850 pwr_move += sds->busiest->__cpu_power *
3851 min(sds->busiest_load_per_task, sds->max_load - tmp);
3853 /* Amount of load we'd add */
3854 if (sds->max_load * sds->busiest->__cpu_power <
3855 sds->busiest_load_per_task * SCHED_LOAD_SCALE)
3856 tmp = sg_div_cpu_power(sds->this,
3857 sds->max_load * sds->busiest->__cpu_power);
3859 tmp = sg_div_cpu_power(sds->this,
3860 sds->busiest_load_per_task * SCHED_LOAD_SCALE);
3861 pwr_move += sds->this->__cpu_power *
3862 min(sds->this_load_per_task, sds->this_load + tmp);
3863 pwr_move /= SCHED_LOAD_SCALE;
3865 /* Move if we gain throughput */
3866 if (pwr_move > pwr_now)
3867 *imbalance = sds->busiest_load_per_task;
3871 * calculate_imbalance - Calculate the amount of imbalance present within the
3872 * groups of a given sched_domain during load balance.
3873 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3874 * @this_cpu: Cpu for which currently load balance is being performed.
3875 * @imbalance: The variable to store the imbalance.
3877 static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
3878 unsigned long *imbalance)
3880 unsigned long max_pull;
3882 * In the presence of smp nice balancing, certain scenarios can have
3883 * max load less than avg load(as we skip the groups at or below
3884 * its cpu_power, while calculating max_load..)
3886 if (sds->max_load < sds->avg_load) {
3888 return fix_small_imbalance(sds, this_cpu, imbalance);
3891 /* Don't want to pull so many tasks that a group would go idle */
3892 max_pull = min(sds->max_load - sds->avg_load,
3893 sds->max_load - sds->busiest_load_per_task);
3895 /* How much load to actually move to equalise the imbalance */
3896 *imbalance = min(max_pull * sds->busiest->__cpu_power,
3897 (sds->avg_load - sds->this_load) * sds->this->__cpu_power)
3901 * if *imbalance is less than the average load per runnable task
3902 * there is no gaurantee that any tasks will be moved so we'll have
3903 * a think about bumping its value to force at least one task to be
3906 if (*imbalance < sds->busiest_load_per_task)
3907 return fix_small_imbalance(sds, this_cpu, imbalance);
3910 /******* find_busiest_group() helpers end here *********************/
3913 * find_busiest_group - Returns the busiest group within the sched_domain
3914 * if there is an imbalance. If there isn't an imbalance, and
3915 * the user has opted for power-savings, it returns a group whose
3916 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3917 * such a group exists.
3919 * Also calculates the amount of weighted load which should be moved
3920 * to restore balance.
3922 * @sd: The sched_domain whose busiest group is to be returned.
3923 * @this_cpu: The cpu for which load balancing is currently being performed.
3924 * @imbalance: Variable which stores amount of weighted load which should
3925 * be moved to restore balance/put a group to idle.
3926 * @idle: The idle status of this_cpu.
3927 * @sd_idle: The idleness of sd
3928 * @cpus: The set of CPUs under consideration for load-balancing.
3929 * @balance: Pointer to a variable indicating if this_cpu
3930 * is the appropriate cpu to perform load balancing at this_level.
3932 * Returns: - the busiest group if imbalance exists.
3933 * - If no imbalance and user has opted for power-savings balance,
3934 * return the least loaded group whose CPUs can be
3935 * put to idle by rebalancing its tasks onto our group.
3937 static struct sched_group *
3938 find_busiest_group(struct sched_domain *sd, int this_cpu,
3939 unsigned long *imbalance, enum cpu_idle_type idle,
3940 int *sd_idle, const struct cpumask *cpus, int *balance)
3942 struct sd_lb_stats sds;
3944 memset(&sds, 0, sizeof(sds));
3947 * Compute the various statistics relavent for load balancing at
3950 update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus,
3953 /* Cases where imbalance does not exist from POV of this_cpu */
3954 /* 1) this_cpu is not the appropriate cpu to perform load balancing
3956 * 2) There is no busy sibling group to pull from.
3957 * 3) This group is the busiest group.
3958 * 4) This group is more busy than the avg busieness at this
3960 * 5) The imbalance is within the specified limit.
3961 * 6) Any rebalance would lead to ping-pong
3963 if (balance && !(*balance))
3966 if (!sds.busiest || sds.busiest_nr_running == 0)
3969 if (sds.this_load >= sds.max_load)
3972 sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
3974 if (sds.this_load >= sds.avg_load)
3977 if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
3980 sds.busiest_load_per_task /= sds.busiest_nr_running;
3982 sds.busiest_load_per_task =
3983 min(sds.busiest_load_per_task, sds.avg_load);
3986 * We're trying to get all the cpus to the average_load, so we don't
3987 * want to push ourselves above the average load, nor do we wish to
3988 * reduce the max loaded cpu below the average load, as either of these
3989 * actions would just result in more rebalancing later, and ping-pong
3990 * tasks around. Thus we look for the minimum possible imbalance.
3991 * Negative imbalances (*we* are more loaded than anyone else) will
3992 * be counted as no imbalance for these purposes -- we can't fix that
3993 * by pulling tasks to us. Be careful of negative numbers as they'll
3994 * appear as very large values with unsigned longs.
3996 if (sds.max_load <= sds.busiest_load_per_task)
3999 /* Looks like there is an imbalance. Compute it */
4000 calculate_imbalance(&sds, this_cpu, imbalance);
4005 * There is no obvious imbalance. But check if we can do some balancing
4008 if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
4016 * find_busiest_queue - find the busiest runqueue among the cpus in group.
4019 find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
4020 unsigned long imbalance, const struct cpumask *cpus)
4022 struct rq *busiest = NULL, *rq;
4023 unsigned long max_load = 0;
4026 for_each_cpu(i, sched_group_cpus(group)) {
4029 if (!cpumask_test_cpu(i, cpus))
4033 wl = weighted_cpuload(i);
4035 if (rq->nr_running == 1 && wl > imbalance)
4038 if (wl > max_load) {
4048 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
4049 * so long as it is large enough.
4051 #define MAX_PINNED_INTERVAL 512
4053 /* Working cpumask for load_balance and load_balance_newidle. */
4054 static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
4057 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4058 * tasks if there is an imbalance.
4060 static int load_balance(int this_cpu, struct rq *this_rq,
4061 struct sched_domain *sd, enum cpu_idle_type idle,
4064 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
4065 struct sched_group *group;
4066 unsigned long imbalance;
4068 unsigned long flags;
4069 struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
4071 cpumask_setall(cpus);
4074 * When power savings policy is enabled for the parent domain, idle
4075 * sibling can pick up load irrespective of busy siblings. In this case,
4076 * let the state of idle sibling percolate up as CPU_IDLE, instead of
4077 * portraying it as CPU_NOT_IDLE.
4079 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
4080 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4083 schedstat_inc(sd, lb_count[idle]);
4087 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
4094 schedstat_inc(sd, lb_nobusyg[idle]);
4098 busiest = find_busiest_queue(group, idle, imbalance, cpus);
4100 schedstat_inc(sd, lb_nobusyq[idle]);
4104 BUG_ON(busiest == this_rq);
4106 schedstat_add(sd, lb_imbalance[idle], imbalance);
4109 if (busiest->nr_running > 1) {
4111 * Attempt to move tasks. If find_busiest_group has found
4112 * an imbalance but busiest->nr_running <= 1, the group is
4113 * still unbalanced. ld_moved simply stays zero, so it is
4114 * correctly treated as an imbalance.
4116 local_irq_save(flags);
4117 double_rq_lock(this_rq, busiest);
4118 ld_moved = move_tasks(this_rq, this_cpu, busiest,
4119 imbalance, sd, idle, &all_pinned);
4120 double_rq_unlock(this_rq, busiest);
4121 local_irq_restore(flags);
4124 * some other cpu did the load balance for us.
4126 if (ld_moved && this_cpu != smp_processor_id())
4127 resched_cpu(this_cpu);
4129 /* All tasks on this runqueue were pinned by CPU affinity */
4130 if (unlikely(all_pinned)) {
4131 cpumask_clear_cpu(cpu_of(busiest), cpus);
4132 if (!cpumask_empty(cpus))
4139 schedstat_inc(sd, lb_failed[idle]);
4140 sd->nr_balance_failed++;
4142 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
4144 spin_lock_irqsave(&busiest->lock, flags);
4146 /* don't kick the migration_thread, if the curr
4147 * task on busiest cpu can't be moved to this_cpu
4149 if (!cpumask_test_cpu(this_cpu,
4150 &busiest->curr->cpus_allowed)) {
4151 spin_unlock_irqrestore(&busiest->lock, flags);
4153 goto out_one_pinned;
4156 if (!busiest->active_balance) {
4157 busiest->active_balance = 1;
4158 busiest->push_cpu = this_cpu;
4161 spin_unlock_irqrestore(&busiest->lock, flags);
4163 wake_up_process(busiest->migration_thread);
4166 * We've kicked active balancing, reset the failure
4169 sd->nr_balance_failed = sd->cache_nice_tries+1;
4172 sd->nr_balance_failed = 0;
4174 if (likely(!active_balance)) {
4175 /* We were unbalanced, so reset the balancing interval */
4176 sd->balance_interval = sd->min_interval;
4179 * If we've begun active balancing, start to back off. This
4180 * case may not be covered by the all_pinned logic if there
4181 * is only 1 task on the busy runqueue (because we don't call
4184 if (sd->balance_interval < sd->max_interval)
4185 sd->balance_interval *= 2;
4188 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4189 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4195 schedstat_inc(sd, lb_balanced[idle]);
4197 sd->nr_balance_failed = 0;
4200 /* tune up the balancing interval */
4201 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
4202 (sd->balance_interval < sd->max_interval))
4203 sd->balance_interval *= 2;
4205 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4206 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4217 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4218 * tasks if there is an imbalance.
4220 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4221 * this_rq is locked.
4224 load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
4226 struct sched_group *group;
4227 struct rq *busiest = NULL;
4228 unsigned long imbalance;
4232 struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
4234 cpumask_setall(cpus);
4237 * When power savings policy is enabled for the parent domain, idle
4238 * sibling can pick up load irrespective of busy siblings. In this case,
4239 * let the state of idle sibling percolate up as IDLE, instead of
4240 * portraying it as CPU_NOT_IDLE.
4242 if (sd->flags & SD_SHARE_CPUPOWER &&
4243 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4246 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
4248 update_shares_locked(this_rq, sd);
4249 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
4250 &sd_idle, cpus, NULL);
4252 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
4256 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
4258 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
4262 BUG_ON(busiest == this_rq);
4264 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
4267 if (busiest->nr_running > 1) {
4268 /* Attempt to move tasks */
4269 double_lock_balance(this_rq, busiest);
4270 /* this_rq->clock is already updated */
4271 update_rq_clock(busiest);
4272 ld_moved = move_tasks(this_rq, this_cpu, busiest,
4273 imbalance, sd, CPU_NEWLY_IDLE,
4275 double_unlock_balance(this_rq, busiest);
4277 if (unlikely(all_pinned)) {
4278 cpumask_clear_cpu(cpu_of(busiest), cpus);
4279 if (!cpumask_empty(cpus))
4285 int active_balance = 0;
4287 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
4288 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4289 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4292 if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
4295 if (sd->nr_balance_failed++ < 2)
4299 * The only task running in a non-idle cpu can be moved to this
4300 * cpu in an attempt to completely freeup the other CPU
4301 * package. The same method used to move task in load_balance()
4302 * have been extended for load_balance_newidle() to speedup
4303 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4305 * The package power saving logic comes from
4306 * find_busiest_group(). If there are no imbalance, then
4307 * f_b_g() will return NULL. However when sched_mc={1,2} then
4308 * f_b_g() will select a group from which a running task may be
4309 * pulled to this cpu in order to make the other package idle.
4310 * If there is no opportunity to make a package idle and if
4311 * there are no imbalance, then f_b_g() will return NULL and no
4312 * action will be taken in load_balance_newidle().
4314 * Under normal task pull operation due to imbalance, there
4315 * will be more than one task in the source run queue and
4316 * move_tasks() will succeed. ld_moved will be true and this
4317 * active balance code will not be triggered.
4320 /* Lock busiest in correct order while this_rq is held */
4321 double_lock_balance(this_rq, busiest);
4324 * don't kick the migration_thread, if the curr
4325 * task on busiest cpu can't be moved to this_cpu
4327 if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) {
4328 double_unlock_balance(this_rq, busiest);
4333 if (!busiest->active_balance) {
4334 busiest->active_balance = 1;
4335 busiest->push_cpu = this_cpu;
4339 double_unlock_balance(this_rq, busiest);
4341 * Should not call ttwu while holding a rq->lock
4343 spin_unlock(&this_rq->lock);
4345 wake_up_process(busiest->migration_thread);
4346 spin_lock(&this_rq->lock);
4349 sd->nr_balance_failed = 0;
4351 update_shares_locked(this_rq, sd);
4355 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
4356 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4357 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4359 sd->nr_balance_failed = 0;
4365 * idle_balance is called by schedule() if this_cpu is about to become
4366 * idle. Attempts to pull tasks from other CPUs.
4368 static void idle_balance(int this_cpu, struct rq *this_rq)
4370 struct sched_domain *sd;
4371 int pulled_task = 0;
4372 unsigned long next_balance = jiffies + HZ;
4374 for_each_domain(this_cpu, sd) {
4375 unsigned long interval;
4377 if (!(sd->flags & SD_LOAD_BALANCE))
4380 if (sd->flags & SD_BALANCE_NEWIDLE)
4381 /* If we've pulled tasks over stop searching: */
4382 pulled_task = load_balance_newidle(this_cpu, this_rq,
4385 interval = msecs_to_jiffies(sd->balance_interval);
4386 if (time_after(next_balance, sd->last_balance + interval))
4387 next_balance = sd->last_balance + interval;
4391 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
4393 * We are going idle. next_balance may be set based on
4394 * a busy processor. So reset next_balance.
4396 this_rq->next_balance = next_balance;
4401 * active_load_balance is run by migration threads. It pushes running tasks
4402 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4403 * running on each physical CPU where possible, and avoids physical /
4404 * logical imbalances.
4406 * Called with busiest_rq locked.
4408 static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
4410 int target_cpu = busiest_rq->push_cpu;
4411 struct sched_domain *sd;
4412 struct rq *target_rq;
4414 /* Is there any task to move? */
4415 if (busiest_rq->nr_running <= 1)
4418 target_rq = cpu_rq(target_cpu);
4421 * This condition is "impossible", if it occurs
4422 * we need to fix it. Originally reported by
4423 * Bjorn Helgaas on a 128-cpu setup.
4425 BUG_ON(busiest_rq == target_rq);
4427 /* move a task from busiest_rq to target_rq */
4428 double_lock_balance(busiest_rq, target_rq);
4429 update_rq_clock(busiest_rq);
4430 update_rq_clock(target_rq);
4432 /* Search for an sd spanning us and the target CPU. */
4433 for_each_domain(target_cpu, sd) {
4434 if ((sd->flags & SD_LOAD_BALANCE) &&
4435 cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
4440 schedstat_inc(sd, alb_count);
4442 if (move_one_task(target_rq, target_cpu, busiest_rq,
4444 schedstat_inc(sd, alb_pushed);
4446 schedstat_inc(sd, alb_failed);
4448 double_unlock_balance(busiest_rq, target_rq);
4453 atomic_t load_balancer;
4454 cpumask_var_t cpu_mask;
4455 cpumask_var_t ilb_grp_nohz_mask;
4456 } nohz ____cacheline_aligned = {
4457 .load_balancer = ATOMIC_INIT(-1),
4460 int get_nohz_load_balancer(void)
4462 return atomic_read(&nohz.load_balancer);
4465 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
4467 * lowest_flag_domain - Return lowest sched_domain containing flag.
4468 * @cpu: The cpu whose lowest level of sched domain is to
4470 * @flag: The flag to check for the lowest sched_domain
4471 * for the given cpu.
4473 * Returns the lowest sched_domain of a cpu which contains the given flag.
4475 static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
4477 struct sched_domain *sd;
4479 for_each_domain(cpu, sd)
4480 if (sd && (sd->flags & flag))
4487 * for_each_flag_domain - Iterates over sched_domains containing the flag.
4488 * @cpu: The cpu whose domains we're iterating over.
4489 * @sd: variable holding the value of the power_savings_sd
4491 * @flag: The flag to filter the sched_domains to be iterated.
4493 * Iterates over all the scheduler domains for a given cpu that has the 'flag'
4494 * set, starting from the lowest sched_domain to the highest.
4496 #define for_each_flag_domain(cpu, sd, flag) \
4497 for (sd = lowest_flag_domain(cpu, flag); \
4498 (sd && (sd->flags & flag)); sd = sd->parent)
4501 * is_semi_idle_group - Checks if the given sched_group is semi-idle.
4502 * @ilb_group: group to be checked for semi-idleness
4504 * Returns: 1 if the group is semi-idle. 0 otherwise.
4506 * We define a sched_group to be semi idle if it has atleast one idle-CPU
4507 * and atleast one non-idle CPU. This helper function checks if the given
4508 * sched_group is semi-idle or not.
4510 static inline int is_semi_idle_group(struct sched_group *ilb_group)
4512 cpumask_and(nohz.ilb_grp_nohz_mask, nohz.cpu_mask,
4513 sched_group_cpus(ilb_group));
4516 * A sched_group is semi-idle when it has atleast one busy cpu
4517 * and atleast one idle cpu.
4519 if (cpumask_empty(nohz.ilb_grp_nohz_mask))
4522 if (cpumask_equal(nohz.ilb_grp_nohz_mask, sched_group_cpus(ilb_group)))
4528 * find_new_ilb - Finds the optimum idle load balancer for nomination.
4529 * @cpu: The cpu which is nominating a new idle_load_balancer.
4531 * Returns: Returns the id of the idle load balancer if it exists,
4532 * Else, returns >= nr_cpu_ids.
4534 * This algorithm picks the idle load balancer such that it belongs to a
4535 * semi-idle powersavings sched_domain. The idea is to try and avoid
4536 * completely idle packages/cores just for the purpose of idle load balancing
4537 * when there are other idle cpu's which are better suited for that job.
4539 static int find_new_ilb(int cpu)
4541 struct sched_domain *sd;
4542 struct sched_group *ilb_group;
4545 * Have idle load balancer selection from semi-idle packages only
4546 * when power-aware load balancing is enabled
4548 if (!(sched_smt_power_savings || sched_mc_power_savings))
4552 * Optimize for the case when we have no idle CPUs or only one
4553 * idle CPU. Don't walk the sched_domain hierarchy in such cases
4555 if (cpumask_weight(nohz.cpu_mask) < 2)
4558 for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) {
4559 ilb_group = sd->groups;
4562 if (is_semi_idle_group(ilb_group))
4563 return cpumask_first(nohz.ilb_grp_nohz_mask);
4565 ilb_group = ilb_group->next;
4567 } while (ilb_group != sd->groups);
4571 return cpumask_first(nohz.cpu_mask);
4573 #else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
4574 static inline int find_new_ilb(int call_cpu)
4576 return cpumask_first(nohz.cpu_mask);
4581 * This routine will try to nominate the ilb (idle load balancing)
4582 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4583 * load balancing on behalf of all those cpus. If all the cpus in the system
4584 * go into this tickless mode, then there will be no ilb owner (as there is
4585 * no need for one) and all the cpus will sleep till the next wakeup event
4588 * For the ilb owner, tick is not stopped. And this tick will be used
4589 * for idle load balancing. ilb owner will still be part of
4592 * While stopping the tick, this cpu will become the ilb owner if there
4593 * is no other owner. And will be the owner till that cpu becomes busy
4594 * or if all cpus in the system stop their ticks at which point
4595 * there is no need for ilb owner.
4597 * When the ilb owner becomes busy, it nominates another owner, during the
4598 * next busy scheduler_tick()
4600 int select_nohz_load_balancer(int stop_tick)
4602 int cpu = smp_processor_id();
4605 cpu_rq(cpu)->in_nohz_recently = 1;
4607 if (!cpu_active(cpu)) {
4608 if (atomic_read(&nohz.load_balancer) != cpu)
4612 * If we are going offline and still the leader,
4615 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
4621 cpumask_set_cpu(cpu, nohz.cpu_mask);
4623 /* time for ilb owner also to sleep */
4624 if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
4625 if (atomic_read(&nohz.load_balancer) == cpu)
4626 atomic_set(&nohz.load_balancer, -1);
4630 if (atomic_read(&nohz.load_balancer) == -1) {
4631 /* make me the ilb owner */
4632 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
4634 } else if (atomic_read(&nohz.load_balancer) == cpu) {
4637 if (!(sched_smt_power_savings ||
4638 sched_mc_power_savings))
4641 * Check to see if there is a more power-efficient
4644 new_ilb = find_new_ilb(cpu);
4645 if (new_ilb < nr_cpu_ids && new_ilb != cpu) {
4646 atomic_set(&nohz.load_balancer, -1);
4647 resched_cpu(new_ilb);
4653 if (!cpumask_test_cpu(cpu, nohz.cpu_mask))
4656 cpumask_clear_cpu(cpu, nohz.cpu_mask);
4658 if (atomic_read(&nohz.load_balancer) == cpu)
4659 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
4666 static DEFINE_SPINLOCK(balancing);
4669 * It checks each scheduling domain to see if it is due to be balanced,
4670 * and initiates a balancing operation if so.
4672 * Balancing parameters are set up in arch_init_sched_domains.
4674 static void rebalance_domains(int cpu, enum cpu_idle_type idle)
4677 struct rq *rq = cpu_rq(cpu);
4678 unsigned long interval;
4679 struct sched_domain *sd;
4680 /* Earliest time when we have to do rebalance again */
4681 unsigned long next_balance = jiffies + 60*HZ;
4682 int update_next_balance = 0;
4685 for_each_domain(cpu, sd) {
4686 if (!(sd->flags & SD_LOAD_BALANCE))
4689 interval = sd->balance_interval;
4690 if (idle != CPU_IDLE)
4691 interval *= sd->busy_factor;
4693 /* scale ms to jiffies */
4694 interval = msecs_to_jiffies(interval);
4695 if (unlikely(!interval))
4697 if (interval > HZ*NR_CPUS/10)
4698 interval = HZ*NR_CPUS/10;
4700 need_serialize = sd->flags & SD_SERIALIZE;
4702 if (need_serialize) {
4703 if (!spin_trylock(&balancing))
4707 if (time_after_eq(jiffies, sd->last_balance + interval)) {
4708 if (load_balance(cpu, rq, sd, idle, &balance)) {
4710 * We've pulled tasks over so either we're no
4711 * longer idle, or one of our SMT siblings is
4714 idle = CPU_NOT_IDLE;
4716 sd->last_balance = jiffies;
4719 spin_unlock(&balancing);
4721 if (time_after(next_balance, sd->last_balance + interval)) {
4722 next_balance = sd->last_balance + interval;
4723 update_next_balance = 1;
4727 * Stop the load balance at this level. There is another
4728 * CPU in our sched group which is doing load balancing more
4736 * next_balance will be updated only when there is a need.
4737 * When the cpu is attached to null domain for ex, it will not be
4740 if (likely(update_next_balance))
4741 rq->next_balance = next_balance;
4745 * run_rebalance_domains is triggered when needed from the scheduler tick.
4746 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4747 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4749 static void run_rebalance_domains(struct softirq_action *h)
4751 int this_cpu = smp_processor_id();
4752 struct rq *this_rq = cpu_rq(this_cpu);
4753 enum cpu_idle_type idle = this_rq->idle_at_tick ?
4754 CPU_IDLE : CPU_NOT_IDLE;
4756 rebalance_domains(this_cpu, idle);
4760 * If this cpu is the owner for idle load balancing, then do the
4761 * balancing on behalf of the other idle cpus whose ticks are
4764 if (this_rq->idle_at_tick &&
4765 atomic_read(&nohz.load_balancer) == this_cpu) {
4769 for_each_cpu(balance_cpu, nohz.cpu_mask) {
4770 if (balance_cpu == this_cpu)
4774 * If this cpu gets work to do, stop the load balancing
4775 * work being done for other cpus. Next load
4776 * balancing owner will pick it up.
4781 rebalance_domains(balance_cpu, CPU_IDLE);
4783 rq = cpu_rq(balance_cpu);
4784 if (time_after(this_rq->next_balance, rq->next_balance))
4785 this_rq->next_balance = rq->next_balance;
4791 static inline int on_null_domain(int cpu)
4793 return !rcu_dereference(cpu_rq(cpu)->sd);
4797 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4799 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4800 * idle load balancing owner or decide to stop the periodic load balancing,
4801 * if the whole system is idle.
4803 static inline void trigger_load_balance(struct rq *rq, int cpu)
4807 * If we were in the nohz mode recently and busy at the current
4808 * scheduler tick, then check if we need to nominate new idle
4811 if (rq->in_nohz_recently && !rq->idle_at_tick) {
4812 rq->in_nohz_recently = 0;
4814 if (atomic_read(&nohz.load_balancer) == cpu) {
4815 cpumask_clear_cpu(cpu, nohz.cpu_mask);
4816 atomic_set(&nohz.load_balancer, -1);
4819 if (atomic_read(&nohz.load_balancer) == -1) {
4820 int ilb = find_new_ilb(cpu);
4822 if (ilb < nr_cpu_ids)
4828 * If this cpu is idle and doing idle load balancing for all the
4829 * cpus with ticks stopped, is it time for that to stop?
4831 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
4832 cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
4838 * If this cpu is idle and the idle load balancing is done by
4839 * someone else, then no need raise the SCHED_SOFTIRQ
4841 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
4842 cpumask_test_cpu(cpu, nohz.cpu_mask))
4845 /* Don't need to rebalance while attached to NULL domain */
4846 if (time_after_eq(jiffies, rq->next_balance) &&
4847 likely(!on_null_domain(cpu)))
4848 raise_softirq(SCHED_SOFTIRQ);
4851 #else /* CONFIG_SMP */
4854 * on UP we do not need to balance between CPUs:
4856 static inline void idle_balance(int cpu, struct rq *rq)
4862 DEFINE_PER_CPU(struct kernel_stat, kstat);
4864 EXPORT_PER_CPU_SYMBOL(kstat);
4867 * Return any ns on the sched_clock that have not yet been accounted in
4868 * @p in case that task is currently running.
4870 * Called with task_rq_lock() held on @rq.
4872 static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
4876 if (task_current(rq, p)) {
4877 update_rq_clock(rq);
4878 ns = rq->clock - p->se.exec_start;
4886 unsigned long long task_delta_exec(struct task_struct *p)
4888 unsigned long flags;
4892 rq = task_rq_lock(p, &flags);
4893 ns = do_task_delta_exec(p, rq);
4894 task_rq_unlock(rq, &flags);
4900 * Return accounted runtime for the task.
4901 * In case the task is currently running, return the runtime plus current's
4902 * pending runtime that have not been accounted yet.
4904 unsigned long long task_sched_runtime(struct task_struct *p)
4906 unsigned long flags;
4910 rq = task_rq_lock(p, &flags);
4911 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
4912 task_rq_unlock(rq, &flags);
4918 * Return sum_exec_runtime for the thread group.
4919 * In case the task is currently running, return the sum plus current's
4920 * pending runtime that have not been accounted yet.
4922 * Note that the thread group might have other running tasks as well,
4923 * so the return value not includes other pending runtime that other
4924 * running tasks might have.
4926 unsigned long long thread_group_sched_runtime(struct task_struct *p)
4928 struct task_cputime totals;
4929 unsigned long flags;
4933 rq = task_rq_lock(p, &flags);
4934 thread_group_cputime(p, &totals);
4935 ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq);
4936 task_rq_unlock(rq, &flags);
4942 * Account user cpu time to a process.
4943 * @p: the process that the cpu time gets accounted to
4944 * @cputime: the cpu time spent in user space since the last update
4945 * @cputime_scaled: cputime scaled by cpu frequency
4947 void account_user_time(struct task_struct *p, cputime_t cputime,
4948 cputime_t cputime_scaled)
4950 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4953 /* Add user time to process. */
4954 p->utime = cputime_add(p->utime, cputime);
4955 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4956 account_group_user_time(p, cputime);
4958 /* Add user time to cpustat. */
4959 tmp = cputime_to_cputime64(cputime);
4960 if (TASK_NICE(p) > 0)
4961 cpustat->nice = cputime64_add(cpustat->nice, tmp);
4963 cpustat->user = cputime64_add(cpustat->user, tmp);
4965 cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime);
4966 /* Account for user time used */
4967 acct_update_integrals(p);
4971 * Account guest cpu time to a process.
4972 * @p: the process that the cpu time gets accounted to
4973 * @cputime: the cpu time spent in virtual machine since the last update
4974 * @cputime_scaled: cputime scaled by cpu frequency
4976 static void account_guest_time(struct task_struct *p, cputime_t cputime,
4977 cputime_t cputime_scaled)
4980 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4982 tmp = cputime_to_cputime64(cputime);
4984 /* Add guest time to process. */
4985 p->utime = cputime_add(p->utime, cputime);
4986 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4987 account_group_user_time(p, cputime);
4988 p->gtime = cputime_add(p->gtime, cputime);
4990 /* Add guest time to cpustat. */
4991 cpustat->user = cputime64_add(cpustat->user, tmp);
4992 cpustat->guest = cputime64_add(cpustat->guest, tmp);
4996 * Account system cpu time to a process.
4997 * @p: the process that the cpu time gets accounted to
4998 * @hardirq_offset: the offset to subtract from hardirq_count()
4999 * @cputime: the cpu time spent in kernel space since the last update
5000 * @cputime_scaled: cputime scaled by cpu frequency
5002 void account_system_time(struct task_struct *p, int hardirq_offset,
5003 cputime_t cputime, cputime_t cputime_scaled)
5005 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
5008 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
5009 account_guest_time(p, cputime, cputime_scaled);
5013 /* Add system time to process. */
5014 p->stime = cputime_add(p->stime, cputime);
5015 p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
5016 account_group_system_time(p, cputime);
5018 /* Add system time to cpustat. */
5019 tmp = cputime_to_cputime64(cputime);
5020 if (hardirq_count() - hardirq_offset)
5021 cpustat->irq = cputime64_add(cpustat->irq, tmp);
5022 else if (softirq_count())
5023 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
5025 cpustat->system = cputime64_add(cpustat->system, tmp);
5027 cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
5029 /* Account for system time used */
5030 acct_update_integrals(p);
5034 * Account for involuntary wait time.
5035 * @steal: the cpu time spent in involuntary wait
5037 void account_steal_time(cputime_t cputime)
5039 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
5040 cputime64_t cputime64 = cputime_to_cputime64(cputime);
5042 cpustat->steal = cputime64_add(cpustat->steal, cputime64);
5046 * Account for idle time.
5047 * @cputime: the cpu time spent in idle wait
5049 void account_idle_time(cputime_t cputime)
5051 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
5052 cputime64_t cputime64 = cputime_to_cputime64(cputime);
5053 struct rq *rq = this_rq();
5055 if (atomic_read(&rq->nr_iowait) > 0)
5056 cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
5058 cpustat->idle = cputime64_add(cpustat->idle, cputime64);
5061 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
5064 * Account a single tick of cpu time.
5065 * @p: the process that the cpu time gets accounted to
5066 * @user_tick: indicates if the tick is a user or a system tick
5068 void account_process_tick(struct task_struct *p, int user_tick)
5070 cputime_t one_jiffy = jiffies_to_cputime(1);
5071 cputime_t one_jiffy_scaled = cputime_to_scaled(one_jiffy);
5072 struct rq *rq = this_rq();
5075 account_user_time(p, one_jiffy, one_jiffy_scaled);
5076 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
5077 account_system_time(p, HARDIRQ_OFFSET, one_jiffy,
5080 account_idle_time(one_jiffy);
5084 * Account multiple ticks of steal time.
5085 * @p: the process from which the cpu time has been stolen
5086 * @ticks: number of stolen ticks
5088 void account_steal_ticks(unsigned long ticks)
5090 account_steal_time(jiffies_to_cputime(ticks));
5094 * Account multiple ticks of idle time.
5095 * @ticks: number of stolen ticks
5097 void account_idle_ticks(unsigned long ticks)
5099 account_idle_time(jiffies_to_cputime(ticks));
5105 * Use precise platform statistics if available:
5107 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
5108 cputime_t task_utime(struct task_struct *p)
5113 cputime_t task_stime(struct task_struct *p)
5118 cputime_t task_utime(struct task_struct *p)
5120 clock_t utime = cputime_to_clock_t(p->utime),
5121 total = utime + cputime_to_clock_t(p->stime);
5125 * Use CFS's precise accounting:
5127 temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
5131 do_div(temp, total);
5133 utime = (clock_t)temp;
5135 p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
5136 return p->prev_utime;
5139 cputime_t task_stime(struct task_struct *p)
5144 * Use CFS's precise accounting. (we subtract utime from
5145 * the total, to make sure the total observed by userspace
5146 * grows monotonically - apps rely on that):
5148 stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
5149 cputime_to_clock_t(task_utime(p));
5152 p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime));
5154 return p->prev_stime;
5158 inline cputime_t task_gtime(struct task_struct *p)
5164 * This function gets called by the timer code, with HZ frequency.
5165 * We call it with interrupts disabled.
5167 * It also gets called by the fork code, when changing the parent's
5170 void scheduler_tick(void)
5172 int cpu = smp_processor_id();
5173 struct rq *rq = cpu_rq(cpu);
5174 struct task_struct *curr = rq->curr;
5178 spin_lock(&rq->lock);
5179 update_rq_clock(rq);
5180 update_cpu_load(rq);
5181 curr->sched_class->task_tick(rq, curr, 0);
5182 spin_unlock(&rq->lock);
5184 perf_counter_task_tick(curr, cpu);
5187 rq->idle_at_tick = idle_cpu(cpu);
5188 trigger_load_balance(rq, cpu);
5192 notrace unsigned long get_parent_ip(unsigned long addr)
5194 if (in_lock_functions(addr)) {
5195 addr = CALLER_ADDR2;
5196 if (in_lock_functions(addr))
5197 addr = CALLER_ADDR3;
5202 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
5203 defined(CONFIG_PREEMPT_TRACER))
5205 void __kprobes add_preempt_count(int val)
5207 #ifdef CONFIG_DEBUG_PREEMPT
5211 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
5214 preempt_count() += val;
5215 #ifdef CONFIG_DEBUG_PREEMPT
5217 * Spinlock count overflowing soon?
5219 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
5222 if (preempt_count() == val)
5223 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
5225 EXPORT_SYMBOL(add_preempt_count);
5227 void __kprobes sub_preempt_count(int val)
5229 #ifdef CONFIG_DEBUG_PREEMPT
5233 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
5236 * Is the spinlock portion underflowing?
5238 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
5239 !(preempt_count() & PREEMPT_MASK)))
5243 if (preempt_count() == val)
5244 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
5245 preempt_count() -= val;
5247 EXPORT_SYMBOL(sub_preempt_count);
5252 * Print scheduling while atomic bug:
5254 static noinline void __schedule_bug(struct task_struct *prev)
5256 struct pt_regs *regs = get_irq_regs();
5258 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
5259 prev->comm, prev->pid, preempt_count());
5261 debug_show_held_locks(prev);
5263 if (irqs_disabled())
5264 print_irqtrace_events(prev);
5273 * Various schedule()-time debugging checks and statistics:
5275 static inline void schedule_debug(struct task_struct *prev)
5278 * Test if we are atomic. Since do_exit() needs to call into
5279 * schedule() atomically, we ignore that path for now.
5280 * Otherwise, whine if we are scheduling when we should not be.
5282 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
5283 __schedule_bug(prev);
5285 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
5287 schedstat_inc(this_rq(), sched_count);
5288 #ifdef CONFIG_SCHEDSTATS
5289 if (unlikely(prev->lock_depth >= 0)) {
5290 schedstat_inc(this_rq(), bkl_count);
5291 schedstat_inc(prev, sched_info.bkl_count);
5296 static void put_prev_task(struct rq *rq, struct task_struct *prev)
5298 if (prev->state == TASK_RUNNING) {
5299 u64 runtime = prev->se.sum_exec_runtime;
5301 runtime -= prev->se.prev_sum_exec_runtime;
5302 runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
5305 * In order to avoid avg_overlap growing stale when we are
5306 * indeed overlapping and hence not getting put to sleep, grow
5307 * the avg_overlap on preemption.
5309 * We use the average preemption runtime because that
5310 * correlates to the amount of cache footprint a task can
5313 update_avg(&prev->se.avg_overlap, runtime);
5315 prev->sched_class->put_prev_task(rq, prev);
5319 * Pick up the highest-prio task:
5321 static inline struct task_struct *
5322 pick_next_task(struct rq *rq)
5324 const struct sched_class *class;
5325 struct task_struct *p;
5328 * Optimization: we know that if all tasks are in
5329 * the fair class we can call that function directly:
5331 if (likely(rq->nr_running == rq->cfs.nr_running)) {
5332 p = fair_sched_class.pick_next_task(rq);
5337 class = sched_class_highest;
5339 p = class->pick_next_task(rq);
5343 * Will never be NULL as the idle class always
5344 * returns a non-NULL p:
5346 class = class->next;
5351 * schedule() is the main scheduler function.
5353 asmlinkage void __sched schedule(void)
5355 struct task_struct *prev, *next;
5356 unsigned long *switch_count;
5362 cpu = smp_processor_id();
5366 switch_count = &prev->nivcsw;
5368 release_kernel_lock(prev);
5369 need_resched_nonpreemptible:
5371 schedule_debug(prev);
5373 if (sched_feat(HRTICK))
5376 spin_lock_irq(&rq->lock);
5377 update_rq_clock(rq);
5378 clear_tsk_need_resched(prev);
5380 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
5381 if (unlikely(signal_pending_state(prev->state, prev)))
5382 prev->state = TASK_RUNNING;
5384 deactivate_task(rq, prev, 1);
5385 switch_count = &prev->nvcsw;
5389 if (prev->sched_class->pre_schedule)
5390 prev->sched_class->pre_schedule(rq, prev);
5393 if (unlikely(!rq->nr_running))
5394 idle_balance(cpu, rq);
5396 put_prev_task(rq, prev);
5397 next = pick_next_task(rq);
5399 if (likely(prev != next)) {
5400 sched_info_switch(prev, next);
5401 perf_counter_task_sched_out(prev, next, cpu);
5407 context_switch(rq, prev, next); /* unlocks the rq */
5409 * the context switch might have flipped the stack from under
5410 * us, hence refresh the local variables.
5412 cpu = smp_processor_id();
5415 spin_unlock_irq(&rq->lock);
5417 if (unlikely(reacquire_kernel_lock(current) < 0))
5418 goto need_resched_nonpreemptible;
5420 preempt_enable_no_resched();
5424 EXPORT_SYMBOL(schedule);
5428 * Look out! "owner" is an entirely speculative pointer
5429 * access and not reliable.
5431 int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
5436 if (!sched_feat(OWNER_SPIN))
5439 #ifdef CONFIG_DEBUG_PAGEALLOC
5441 * Need to access the cpu field knowing that
5442 * DEBUG_PAGEALLOC could have unmapped it if
5443 * the mutex owner just released it and exited.
5445 if (probe_kernel_address(&owner->cpu, cpu))
5452 * Even if the access succeeded (likely case),
5453 * the cpu field may no longer be valid.
5455 if (cpu >= nr_cpumask_bits)
5459 * We need to validate that we can do a
5460 * get_cpu() and that we have the percpu area.
5462 if (!cpu_online(cpu))
5469 * Owner changed, break to re-assess state.
5471 if (lock->owner != owner)
5475 * Is that owner really running on that cpu?
5477 if (task_thread_info(rq->curr) != owner || need_resched())
5487 #ifdef CONFIG_PREEMPT
5489 * this is the entry point to schedule() from in-kernel preemption
5490 * off of preempt_enable. Kernel preemptions off return from interrupt
5491 * occur there and call schedule directly.
5493 asmlinkage void __sched preempt_schedule(void)
5495 struct thread_info *ti = current_thread_info();
5498 * If there is a non-zero preempt_count or interrupts are disabled,
5499 * we do not want to preempt the current task. Just return..
5501 if (likely(ti->preempt_count || irqs_disabled()))
5505 add_preempt_count(PREEMPT_ACTIVE);
5507 sub_preempt_count(PREEMPT_ACTIVE);
5510 * Check again in case we missed a preemption opportunity
5511 * between schedule and now.
5514 } while (need_resched());
5516 EXPORT_SYMBOL(preempt_schedule);
5519 * this is the entry point to schedule() from kernel preemption
5520 * off of irq context.
5521 * Note, that this is called and return with irqs disabled. This will
5522 * protect us against recursive calling from irq.
5524 asmlinkage void __sched preempt_schedule_irq(void)
5526 struct thread_info *ti = current_thread_info();
5528 /* Catch callers which need to be fixed */
5529 BUG_ON(ti->preempt_count || !irqs_disabled());
5532 add_preempt_count(PREEMPT_ACTIVE);
5535 local_irq_disable();
5536 sub_preempt_count(PREEMPT_ACTIVE);
5539 * Check again in case we missed a preemption opportunity
5540 * between schedule and now.
5543 } while (need_resched());
5546 #endif /* CONFIG_PREEMPT */
5548 int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
5551 return try_to_wake_up(curr->private, mode, sync);
5553 EXPORT_SYMBOL(default_wake_function);
5556 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5557 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5558 * number) then we wake all the non-exclusive tasks and one exclusive task.
5560 * There are circumstances in which we can try to wake a task which has already
5561 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5562 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5564 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
5565 int nr_exclusive, int sync, void *key)
5567 wait_queue_t *curr, *next;
5569 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
5570 unsigned flags = curr->flags;
5572 if (curr->func(curr, mode, sync, key) &&
5573 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
5579 * __wake_up - wake up threads blocked on a waitqueue.
5581 * @mode: which threads
5582 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5583 * @key: is directly passed to the wakeup function
5585 * It may be assumed that this function implies a write memory barrier before
5586 * changing the task state if and only if any tasks are woken up.
5588 void __wake_up(wait_queue_head_t *q, unsigned int mode,
5589 int nr_exclusive, void *key)
5591 unsigned long flags;
5593 spin_lock_irqsave(&q->lock, flags);
5594 __wake_up_common(q, mode, nr_exclusive, 0, key);
5595 spin_unlock_irqrestore(&q->lock, flags);
5597 EXPORT_SYMBOL(__wake_up);
5600 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5602 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
5604 __wake_up_common(q, mode, 1, 0, NULL);
5607 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
5609 __wake_up_common(q, mode, 1, 0, key);
5613 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5615 * @mode: which threads
5616 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5617 * @key: opaque value to be passed to wakeup targets
5619 * The sync wakeup differs that the waker knows that it will schedule
5620 * away soon, so while the target thread will be woken up, it will not
5621 * be migrated to another CPU - ie. the two threads are 'synchronized'
5622 * with each other. This can prevent needless bouncing between CPUs.
5624 * On UP it can prevent extra preemption.
5626 * It may be assumed that this function implies a write memory barrier before
5627 * changing the task state if and only if any tasks are woken up.
5629 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
5630 int nr_exclusive, void *key)
5632 unsigned long flags;
5638 if (unlikely(!nr_exclusive))
5641 spin_lock_irqsave(&q->lock, flags);
5642 __wake_up_common(q, mode, nr_exclusive, sync, key);
5643 spin_unlock_irqrestore(&q->lock, flags);
5645 EXPORT_SYMBOL_GPL(__wake_up_sync_key);
5648 * __wake_up_sync - see __wake_up_sync_key()
5650 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
5652 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
5654 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
5657 * complete: - signals a single thread waiting on this completion
5658 * @x: holds the state of this particular completion
5660 * This will wake up a single thread waiting on this completion. Threads will be
5661 * awakened in the same order in which they were queued.
5663 * See also complete_all(), wait_for_completion() and related routines.
5665 * It may be assumed that this function implies a write memory barrier before
5666 * changing the task state if and only if any tasks are woken up.
5668 void complete(struct completion *x)
5670 unsigned long flags;
5672 spin_lock_irqsave(&x->wait.lock, flags);
5674 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
5675 spin_unlock_irqrestore(&x->wait.lock, flags);
5677 EXPORT_SYMBOL(complete);
5680 * complete_all: - signals all threads waiting on this completion
5681 * @x: holds the state of this particular completion
5683 * This will wake up all threads waiting on this particular completion event.
5685 * It may be assumed that this function implies a write memory barrier before
5686 * changing the task state if and only if any tasks are woken up.
5688 void complete_all(struct completion *x)
5690 unsigned long flags;
5692 spin_lock_irqsave(&x->wait.lock, flags);
5693 x->done += UINT_MAX/2;
5694 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
5695 spin_unlock_irqrestore(&x->wait.lock, flags);
5697 EXPORT_SYMBOL(complete_all);
5699 static inline long __sched
5700 do_wait_for_common(struct completion *x, long timeout, int state)
5703 DECLARE_WAITQUEUE(wait, current);
5705 wait.flags |= WQ_FLAG_EXCLUSIVE;
5706 __add_wait_queue_tail(&x->wait, &wait);
5708 if (signal_pending_state(state, current)) {
5709 timeout = -ERESTARTSYS;
5712 __set_current_state(state);
5713 spin_unlock_irq(&x->wait.lock);
5714 timeout = schedule_timeout(timeout);
5715 spin_lock_irq(&x->wait.lock);
5716 } while (!x->done && timeout);
5717 __remove_wait_queue(&x->wait, &wait);
5722 return timeout ?: 1;
5726 wait_for_common(struct completion *x, long timeout, int state)
5730 spin_lock_irq(&x->wait.lock);
5731 timeout = do_wait_for_common(x, timeout, state);
5732 spin_unlock_irq(&x->wait.lock);
5737 * wait_for_completion: - waits for completion of a task
5738 * @x: holds the state of this particular completion
5740 * This waits to be signaled for completion of a specific task. It is NOT
5741 * interruptible and there is no timeout.
5743 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5744 * and interrupt capability. Also see complete().
5746 void __sched wait_for_completion(struct completion *x)
5748 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
5750 EXPORT_SYMBOL(wait_for_completion);
5753 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5754 * @x: holds the state of this particular completion
5755 * @timeout: timeout value in jiffies
5757 * This waits for either a completion of a specific task to be signaled or for a
5758 * specified timeout to expire. The timeout is in jiffies. It is not
5761 unsigned long __sched
5762 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
5764 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
5766 EXPORT_SYMBOL(wait_for_completion_timeout);
5769 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5770 * @x: holds the state of this particular completion
5772 * This waits for completion of a specific task to be signaled. It is
5775 int __sched wait_for_completion_interruptible(struct completion *x)
5777 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
5778 if (t == -ERESTARTSYS)
5782 EXPORT_SYMBOL(wait_for_completion_interruptible);
5785 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5786 * @x: holds the state of this particular completion
5787 * @timeout: timeout value in jiffies
5789 * This waits for either a completion of a specific task to be signaled or for a
5790 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5792 unsigned long __sched
5793 wait_for_completion_interruptible_timeout(struct completion *x,
5794 unsigned long timeout)
5796 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
5798 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
5801 * wait_for_completion_killable: - waits for completion of a task (killable)
5802 * @x: holds the state of this particular completion
5804 * This waits to be signaled for completion of a specific task. It can be
5805 * interrupted by a kill signal.
5807 int __sched wait_for_completion_killable(struct completion *x)
5809 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
5810 if (t == -ERESTARTSYS)
5814 EXPORT_SYMBOL(wait_for_completion_killable);
5817 * try_wait_for_completion - try to decrement a completion without blocking
5818 * @x: completion structure
5820 * Returns: 0 if a decrement cannot be done without blocking
5821 * 1 if a decrement succeeded.
5823 * If a completion is being used as a counting completion,
5824 * attempt to decrement the counter without blocking. This
5825 * enables us to avoid waiting if the resource the completion
5826 * is protecting is not available.
5828 bool try_wait_for_completion(struct completion *x)
5832 spin_lock_irq(&x->wait.lock);
5837 spin_unlock_irq(&x->wait.lock);
5840 EXPORT_SYMBOL(try_wait_for_completion);
5843 * completion_done - Test to see if a completion has any waiters
5844 * @x: completion structure
5846 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5847 * 1 if there are no waiters.
5850 bool completion_done(struct completion *x)
5854 spin_lock_irq(&x->wait.lock);
5857 spin_unlock_irq(&x->wait.lock);
5860 EXPORT_SYMBOL(completion_done);
5863 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
5865 unsigned long flags;
5868 init_waitqueue_entry(&wait, current);
5870 __set_current_state(state);
5872 spin_lock_irqsave(&q->lock, flags);
5873 __add_wait_queue(q, &wait);
5874 spin_unlock(&q->lock);
5875 timeout = schedule_timeout(timeout);
5876 spin_lock_irq(&q->lock);
5877 __remove_wait_queue(q, &wait);
5878 spin_unlock_irqrestore(&q->lock, flags);
5883 void __sched interruptible_sleep_on(wait_queue_head_t *q)
5885 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
5887 EXPORT_SYMBOL(interruptible_sleep_on);
5890 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
5892 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
5894 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
5896 void __sched sleep_on(wait_queue_head_t *q)
5898 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
5900 EXPORT_SYMBOL(sleep_on);
5902 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
5904 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
5906 EXPORT_SYMBOL(sleep_on_timeout);
5908 #ifdef CONFIG_RT_MUTEXES
5911 * rt_mutex_setprio - set the current priority of a task
5913 * @prio: prio value (kernel-internal form)
5915 * This function changes the 'effective' priority of a task. It does
5916 * not touch ->normal_prio like __setscheduler().
5918 * Used by the rt_mutex code to implement priority inheritance logic.
5920 void rt_mutex_setprio(struct task_struct *p, int prio)
5922 unsigned long flags;
5923 int oldprio, on_rq, running;
5925 const struct sched_class *prev_class = p->sched_class;
5927 BUG_ON(prio < 0 || prio > MAX_PRIO);
5929 rq = task_rq_lock(p, &flags);
5930 update_rq_clock(rq);
5933 on_rq = p->se.on_rq;
5934 running = task_current(rq, p);
5936 dequeue_task(rq, p, 0);
5938 p->sched_class->put_prev_task(rq, p);
5941 p->sched_class = &rt_sched_class;
5943 p->sched_class = &fair_sched_class;
5948 p->sched_class->set_curr_task(rq);
5950 enqueue_task(rq, p, 0);
5952 check_class_changed(rq, p, prev_class, oldprio, running);
5954 task_rq_unlock(rq, &flags);
5959 void set_user_nice(struct task_struct *p, long nice)
5961 int old_prio, delta, on_rq;
5962 unsigned long flags;
5965 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
5968 * We have to be careful, if called from sys_setpriority(),
5969 * the task might be in the middle of scheduling on another CPU.
5971 rq = task_rq_lock(p, &flags);
5972 update_rq_clock(rq);
5974 * The RT priorities are set via sched_setscheduler(), but we still
5975 * allow the 'normal' nice value to be set - but as expected
5976 * it wont have any effect on scheduling until the task is
5977 * SCHED_FIFO/SCHED_RR:
5979 if (task_has_rt_policy(p)) {
5980 p->static_prio = NICE_TO_PRIO(nice);
5983 on_rq = p->se.on_rq;
5985 dequeue_task(rq, p, 0);
5987 p->static_prio = NICE_TO_PRIO(nice);
5990 p->prio = effective_prio(p);
5991 delta = p->prio - old_prio;
5994 enqueue_task(rq, p, 0);
5996 * If the task increased its priority or is running and
5997 * lowered its priority, then reschedule its CPU:
5999 if (delta < 0 || (delta > 0 && task_running(rq, p)))
6000 resched_task(rq->curr);
6003 task_rq_unlock(rq, &flags);
6005 EXPORT_SYMBOL(set_user_nice);
6008 * can_nice - check if a task can reduce its nice value
6012 int can_nice(const struct task_struct *p, const int nice)
6014 /* convert nice value [19,-20] to rlimit style value [1,40] */
6015 int nice_rlim = 20 - nice;
6017 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
6018 capable(CAP_SYS_NICE));
6021 #ifdef __ARCH_WANT_SYS_NICE
6024 * sys_nice - change the priority of the current process.
6025 * @increment: priority increment
6027 * sys_setpriority is a more generic, but much slower function that
6028 * does similar things.
6030 SYSCALL_DEFINE1(nice, int, increment)
6035 * Setpriority might change our priority at the same moment.
6036 * We don't have to worry. Conceptually one call occurs first
6037 * and we have a single winner.
6039 if (increment < -40)
6044 nice = TASK_NICE(current) + increment;
6050 if (increment < 0 && !can_nice(current, nice))
6053 retval = security_task_setnice(current, nice);
6057 set_user_nice(current, nice);
6064 * task_prio - return the priority value of a given task.
6065 * @p: the task in question.
6067 * This is the priority value as seen by users in /proc.
6068 * RT tasks are offset by -200. Normal tasks are centered
6069 * around 0, value goes from -16 to +15.
6071 int task_prio(const struct task_struct *p)
6073 return p->prio - MAX_RT_PRIO;
6077 * task_nice - return the nice value of a given task.
6078 * @p: the task in question.
6080 int task_nice(const struct task_struct *p)
6082 return TASK_NICE(p);
6084 EXPORT_SYMBOL(task_nice);
6087 * idle_cpu - is a given cpu idle currently?
6088 * @cpu: the processor in question.
6090 int idle_cpu(int cpu)
6092 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
6096 * idle_task - return the idle task for a given cpu.
6097 * @cpu: the processor in question.
6099 struct task_struct *idle_task(int cpu)
6101 return cpu_rq(cpu)->idle;
6105 * find_process_by_pid - find a process with a matching PID value.
6106 * @pid: the pid in question.
6108 static struct task_struct *find_process_by_pid(pid_t pid)
6110 return pid ? find_task_by_vpid(pid) : current;
6113 /* Actually do priority change: must hold rq lock. */
6115 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
6117 BUG_ON(p->se.on_rq);
6120 switch (p->policy) {
6124 p->sched_class = &fair_sched_class;
6128 p->sched_class = &rt_sched_class;
6132 p->rt_priority = prio;
6133 p->normal_prio = normal_prio(p);
6134 /* we are holding p->pi_lock already */
6135 p->prio = rt_mutex_getprio(p);
6140 * check the target process has a UID that matches the current process's
6142 static bool check_same_owner(struct task_struct *p)
6144 const struct cred *cred = current_cred(), *pcred;
6148 pcred = __task_cred(p);
6149 match = (cred->euid == pcred->euid ||
6150 cred->euid == pcred->uid);
6155 static int __sched_setscheduler(struct task_struct *p, int policy,
6156 struct sched_param *param, bool user)
6158 int retval, oldprio, oldpolicy = -1, on_rq, running;
6159 unsigned long flags;
6160 const struct sched_class *prev_class = p->sched_class;
6164 /* may grab non-irq protected spin_locks */
6165 BUG_ON(in_interrupt());
6167 /* double check policy once rq lock held */
6169 reset_on_fork = p->sched_reset_on_fork;
6170 policy = oldpolicy = p->policy;
6172 reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);
6173 policy &= ~SCHED_RESET_ON_FORK;
6175 if (policy != SCHED_FIFO && policy != SCHED_RR &&
6176 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
6177 policy != SCHED_IDLE)
6182 * Valid priorities for SCHED_FIFO and SCHED_RR are
6183 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
6184 * SCHED_BATCH and SCHED_IDLE is 0.
6186 if (param->sched_priority < 0 ||
6187 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
6188 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
6190 if (rt_policy(policy) != (param->sched_priority != 0))
6194 * Allow unprivileged RT tasks to decrease priority:
6196 if (user && !capable(CAP_SYS_NICE)) {
6197 if (rt_policy(policy)) {
6198 unsigned long rlim_rtprio;
6200 if (!lock_task_sighand(p, &flags))
6202 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
6203 unlock_task_sighand(p, &flags);
6205 /* can't set/change the rt policy */
6206 if (policy != p->policy && !rlim_rtprio)
6209 /* can't increase priority */
6210 if (param->sched_priority > p->rt_priority &&
6211 param->sched_priority > rlim_rtprio)
6215 * Like positive nice levels, dont allow tasks to
6216 * move out of SCHED_IDLE either:
6218 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
6221 /* can't change other user's priorities */
6222 if (!check_same_owner(p))
6225 /* Normal users shall not reset the sched_reset_on_fork flag */
6226 if (p->sched_reset_on_fork && !reset_on_fork)
6231 #ifdef CONFIG_RT_GROUP_SCHED
6233 * Do not allow realtime tasks into groups that have no runtime
6236 if (rt_bandwidth_enabled() && rt_policy(policy) &&
6237 task_group(p)->rt_bandwidth.rt_runtime == 0)
6241 retval = security_task_setscheduler(p, policy, param);
6247 * make sure no PI-waiters arrive (or leave) while we are
6248 * changing the priority of the task:
6250 spin_lock_irqsave(&p->pi_lock, flags);
6252 * To be able to change p->policy safely, the apropriate
6253 * runqueue lock must be held.
6255 rq = __task_rq_lock(p);
6256 /* recheck policy now with rq lock held */
6257 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
6258 policy = oldpolicy = -1;
6259 __task_rq_unlock(rq);
6260 spin_unlock_irqrestore(&p->pi_lock, flags);
6263 update_rq_clock(rq);
6264 on_rq = p->se.on_rq;
6265 running = task_current(rq, p);
6267 deactivate_task(rq, p, 0);
6269 p->sched_class->put_prev_task(rq, p);
6271 p->sched_reset_on_fork = reset_on_fork;
6274 __setscheduler(rq, p, policy, param->sched_priority);
6277 p->sched_class->set_curr_task(rq);
6279 activate_task(rq, p, 0);
6281 check_class_changed(rq, p, prev_class, oldprio, running);
6283 __task_rq_unlock(rq);
6284 spin_unlock_irqrestore(&p->pi_lock, flags);
6286 rt_mutex_adjust_pi(p);
6292 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
6293 * @p: the task in question.
6294 * @policy: new policy.
6295 * @param: structure containing the new RT priority.
6297 * NOTE that the task may be already dead.
6299 int sched_setscheduler(struct task_struct *p, int policy,
6300 struct sched_param *param)
6302 return __sched_setscheduler(p, policy, param, true);
6304 EXPORT_SYMBOL_GPL(sched_setscheduler);
6307 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
6308 * @p: the task in question.
6309 * @policy: new policy.
6310 * @param: structure containing the new RT priority.
6312 * Just like sched_setscheduler, only don't bother checking if the
6313 * current context has permission. For example, this is needed in
6314 * stop_machine(): we create temporary high priority worker threads,
6315 * but our caller might not have that capability.
6317 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
6318 struct sched_param *param)
6320 return __sched_setscheduler(p, policy, param, false);
6324 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
6326 struct sched_param lparam;
6327 struct task_struct *p;
6330 if (!param || pid < 0)
6332 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
6337 p = find_process_by_pid(pid);
6339 retval = sched_setscheduler(p, policy, &lparam);
6346 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
6347 * @pid: the pid in question.
6348 * @policy: new policy.
6349 * @param: structure containing the new RT priority.
6351 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
6352 struct sched_param __user *, param)
6354 /* negative values for policy are not valid */
6358 return do_sched_setscheduler(pid, policy, param);
6362 * sys_sched_setparam - set/change the RT priority of a thread
6363 * @pid: the pid in question.
6364 * @param: structure containing the new RT priority.
6366 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
6368 return do_sched_setscheduler(pid, -1, param);
6372 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6373 * @pid: the pid in question.
6375 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
6377 struct task_struct *p;
6384 read_lock(&tasklist_lock);
6385 p = find_process_by_pid(pid);
6387 retval = security_task_getscheduler(p);
6390 | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0);
6392 read_unlock(&tasklist_lock);
6397 * sys_sched_getparam - get the RT priority of a thread
6398 * @pid: the pid in question.
6399 * @param: structure containing the RT priority.
6401 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
6403 struct sched_param lp;
6404 struct task_struct *p;
6407 if (!param || pid < 0)
6410 read_lock(&tasklist_lock);
6411 p = find_process_by_pid(pid);
6416 retval = security_task_getscheduler(p);
6420 lp.sched_priority = p->rt_priority;
6421 read_unlock(&tasklist_lock);
6424 * This one might sleep, we cannot do it with a spinlock held ...
6426 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
6431 read_unlock(&tasklist_lock);
6435 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
6437 cpumask_var_t cpus_allowed, new_mask;
6438 struct task_struct *p;
6442 read_lock(&tasklist_lock);
6444 p = find_process_by_pid(pid);
6446 read_unlock(&tasklist_lock);
6452 * It is not safe to call set_cpus_allowed with the
6453 * tasklist_lock held. We will bump the task_struct's
6454 * usage count and then drop tasklist_lock.
6457 read_unlock(&tasklist_lock);
6459 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
6463 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
6465 goto out_free_cpus_allowed;
6468 if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
6471 retval = security_task_setscheduler(p, 0, NULL);
6475 cpuset_cpus_allowed(p, cpus_allowed);
6476 cpumask_and(new_mask, in_mask, cpus_allowed);
6478 retval = set_cpus_allowed_ptr(p, new_mask);
6481 cpuset_cpus_allowed(p, cpus_allowed);
6482 if (!cpumask_subset(new_mask, cpus_allowed)) {
6484 * We must have raced with a concurrent cpuset
6485 * update. Just reset the cpus_allowed to the
6486 * cpuset's cpus_allowed
6488 cpumask_copy(new_mask, cpus_allowed);
6493 free_cpumask_var(new_mask);
6494 out_free_cpus_allowed:
6495 free_cpumask_var(cpus_allowed);
6502 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
6503 struct cpumask *new_mask)
6505 if (len < cpumask_size())
6506 cpumask_clear(new_mask);
6507 else if (len > cpumask_size())
6508 len = cpumask_size();
6510 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
6514 * sys_sched_setaffinity - set the cpu affinity of a process
6515 * @pid: pid of the process
6516 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6517 * @user_mask_ptr: user-space pointer to the new cpu mask
6519 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
6520 unsigned long __user *, user_mask_ptr)
6522 cpumask_var_t new_mask;
6525 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
6528 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
6530 retval = sched_setaffinity(pid, new_mask);
6531 free_cpumask_var(new_mask);
6535 long sched_getaffinity(pid_t pid, struct cpumask *mask)
6537 struct task_struct *p;
6541 read_lock(&tasklist_lock);
6544 p = find_process_by_pid(pid);
6548 retval = security_task_getscheduler(p);
6552 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
6555 read_unlock(&tasklist_lock);
6562 * sys_sched_getaffinity - get the cpu affinity of a process
6563 * @pid: pid of the process
6564 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6565 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6567 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
6568 unsigned long __user *, user_mask_ptr)
6573 if (len < cpumask_size())
6576 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
6579 ret = sched_getaffinity(pid, mask);
6581 if (copy_to_user(user_mask_ptr, mask, cpumask_size()))
6584 ret = cpumask_size();
6586 free_cpumask_var(mask);
6592 * sys_sched_yield - yield the current processor to other threads.
6594 * This function yields the current CPU to other tasks. If there are no
6595 * other threads running on this CPU then this function will return.
6597 SYSCALL_DEFINE0(sched_yield)
6599 struct rq *rq = this_rq_lock();
6601 schedstat_inc(rq, yld_count);
6602 current->sched_class->yield_task(rq);
6605 * Since we are going to call schedule() anyway, there's
6606 * no need to preempt or enable interrupts:
6608 __release(rq->lock);
6609 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
6610 _raw_spin_unlock(&rq->lock);
6611 preempt_enable_no_resched();
6618 static inline int should_resched(void)
6620 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
6623 static void __cond_resched(void)
6625 add_preempt_count(PREEMPT_ACTIVE);
6627 sub_preempt_count(PREEMPT_ACTIVE);
6630 int __sched _cond_resched(void)
6632 if (should_resched()) {
6638 EXPORT_SYMBOL(_cond_resched);
6641 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
6642 * call schedule, and on return reacquire the lock.
6644 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6645 * operations here to prevent schedule() from being called twice (once via
6646 * spin_unlock(), once by hand).
6648 int __cond_resched_lock(spinlock_t *lock)
6650 int resched = should_resched();
6653 if (spin_needbreak(lock) || resched) {
6664 EXPORT_SYMBOL(__cond_resched_lock);
6666 int __sched __cond_resched_softirq(void)
6668 BUG_ON(!in_softirq());
6670 if (should_resched()) {
6678 EXPORT_SYMBOL(__cond_resched_softirq);
6681 * yield - yield the current processor to other threads.
6683 * This is a shortcut for kernel-space yielding - it marks the
6684 * thread runnable and calls sys_sched_yield().
6686 void __sched yield(void)
6688 set_current_state(TASK_RUNNING);
6691 EXPORT_SYMBOL(yield);
6694 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6695 * that process accounting knows that this is a task in IO wait state.
6697 * But don't do that if it is a deliberate, throttling IO wait (this task
6698 * has set its backing_dev_info: the queue against which it should throttle)
6700 void __sched io_schedule(void)
6702 struct rq *rq = raw_rq();
6704 delayacct_blkio_start();
6705 atomic_inc(&rq->nr_iowait);
6707 atomic_dec(&rq->nr_iowait);
6708 delayacct_blkio_end();
6710 EXPORT_SYMBOL(io_schedule);
6712 long __sched io_schedule_timeout(long timeout)
6714 struct rq *rq = raw_rq();
6717 delayacct_blkio_start();
6718 atomic_inc(&rq->nr_iowait);
6719 ret = schedule_timeout(timeout);
6720 atomic_dec(&rq->nr_iowait);
6721 delayacct_blkio_end();
6726 * sys_sched_get_priority_max - return maximum RT priority.
6727 * @policy: scheduling class.
6729 * this syscall returns the maximum rt_priority that can be used
6730 * by a given scheduling class.
6732 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
6739 ret = MAX_USER_RT_PRIO-1;
6751 * sys_sched_get_priority_min - return minimum RT priority.
6752 * @policy: scheduling class.
6754 * this syscall returns the minimum rt_priority that can be used
6755 * by a given scheduling class.
6757 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
6775 * sys_sched_rr_get_interval - return the default timeslice of a process.
6776 * @pid: pid of the process.
6777 * @interval: userspace pointer to the timeslice value.
6779 * this syscall writes the default timeslice value of a given process
6780 * into the user-space timespec buffer. A value of '0' means infinity.
6782 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
6783 struct timespec __user *, interval)
6785 struct task_struct *p;
6786 unsigned int time_slice;
6794 read_lock(&tasklist_lock);
6795 p = find_process_by_pid(pid);
6799 retval = security_task_getscheduler(p);
6804 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6805 * tasks that are on an otherwise idle runqueue:
6808 if (p->policy == SCHED_RR) {
6809 time_slice = DEF_TIMESLICE;
6810 } else if (p->policy != SCHED_FIFO) {
6811 struct sched_entity *se = &p->se;
6812 unsigned long flags;
6815 rq = task_rq_lock(p, &flags);
6816 if (rq->cfs.load.weight)
6817 time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
6818 task_rq_unlock(rq, &flags);
6820 read_unlock(&tasklist_lock);
6821 jiffies_to_timespec(time_slice, &t);
6822 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
6826 read_unlock(&tasklist_lock);
6830 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
6832 void sched_show_task(struct task_struct *p)
6834 unsigned long free = 0;
6837 state = p->state ? __ffs(p->state) + 1 : 0;
6838 printk(KERN_INFO "%-13.13s %c", p->comm,
6839 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
6840 #if BITS_PER_LONG == 32
6841 if (state == TASK_RUNNING)
6842 printk(KERN_CONT " running ");
6844 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
6846 if (state == TASK_RUNNING)
6847 printk(KERN_CONT " running task ");
6849 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
6851 #ifdef CONFIG_DEBUG_STACK_USAGE
6852 free = stack_not_used(p);
6854 printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
6855 task_pid_nr(p), task_pid_nr(p->real_parent),
6856 (unsigned long)task_thread_info(p)->flags);
6858 show_stack(p, NULL);
6861 void show_state_filter(unsigned long state_filter)
6863 struct task_struct *g, *p;
6865 #if BITS_PER_LONG == 32
6867 " task PC stack pid father\n");
6870 " task PC stack pid father\n");
6872 read_lock(&tasklist_lock);
6873 do_each_thread(g, p) {
6875 * reset the NMI-timeout, listing all files on a slow
6876 * console might take alot of time:
6878 touch_nmi_watchdog();
6879 if (!state_filter || (p->state & state_filter))
6881 } while_each_thread(g, p);
6883 touch_all_softlockup_watchdogs();
6885 #ifdef CONFIG_SCHED_DEBUG
6886 sysrq_sched_debug_show();
6888 read_unlock(&tasklist_lock);
6890 * Only show locks if all tasks are dumped:
6892 if (state_filter == -1)
6893 debug_show_all_locks();
6896 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
6898 idle->sched_class = &idle_sched_class;
6902 * init_idle - set up an idle thread for a given CPU
6903 * @idle: task in question
6904 * @cpu: cpu the idle task belongs to
6906 * NOTE: this function does not set the idle thread's NEED_RESCHED
6907 * flag, to make booting more robust.
6909 void __cpuinit init_idle(struct task_struct *idle, int cpu)
6911 struct rq *rq = cpu_rq(cpu);
6912 unsigned long flags;
6914 spin_lock_irqsave(&rq->lock, flags);
6917 idle->se.exec_start = sched_clock();
6919 idle->prio = idle->normal_prio = MAX_PRIO;
6920 cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
6921 __set_task_cpu(idle, cpu);
6923 rq->curr = rq->idle = idle;
6924 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6927 spin_unlock_irqrestore(&rq->lock, flags);
6929 /* Set the preempt count _outside_ the spinlocks! */
6930 #if defined(CONFIG_PREEMPT)
6931 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
6933 task_thread_info(idle)->preempt_count = 0;
6936 * The idle tasks have their own, simple scheduling class:
6938 idle->sched_class = &idle_sched_class;
6939 ftrace_graph_init_task(idle);
6943 * In a system that switches off the HZ timer nohz_cpu_mask
6944 * indicates which cpus entered this state. This is used
6945 * in the rcu update to wait only for active cpus. For system
6946 * which do not switch off the HZ timer nohz_cpu_mask should
6947 * always be CPU_BITS_NONE.
6949 cpumask_var_t nohz_cpu_mask;
6952 * Increase the granularity value when there are more CPUs,
6953 * because with more CPUs the 'effective latency' as visible
6954 * to users decreases. But the relationship is not linear,
6955 * so pick a second-best guess by going with the log2 of the
6958 * This idea comes from the SD scheduler of Con Kolivas:
6960 static inline void sched_init_granularity(void)
6962 unsigned int factor = 1 + ilog2(num_online_cpus());
6963 const unsigned long limit = 200000000;
6965 sysctl_sched_min_granularity *= factor;
6966 if (sysctl_sched_min_granularity > limit)
6967 sysctl_sched_min_granularity = limit;
6969 sysctl_sched_latency *= factor;
6970 if (sysctl_sched_latency > limit)
6971 sysctl_sched_latency = limit;
6973 sysctl_sched_wakeup_granularity *= factor;
6975 sysctl_sched_shares_ratelimit *= factor;
6980 * This is how migration works:
6982 * 1) we queue a struct migration_req structure in the source CPU's
6983 * runqueue and wake up that CPU's migration thread.
6984 * 2) we down() the locked semaphore => thread blocks.
6985 * 3) migration thread wakes up (implicitly it forces the migrated
6986 * thread off the CPU)
6987 * 4) it gets the migration request and checks whether the migrated
6988 * task is still in the wrong runqueue.
6989 * 5) if it's in the wrong runqueue then the migration thread removes
6990 * it and puts it into the right queue.
6991 * 6) migration thread up()s the semaphore.
6992 * 7) we wake up and the migration is done.
6996 * Change a given task's CPU affinity. Migrate the thread to a
6997 * proper CPU and schedule it away if the CPU it's executing on
6998 * is removed from the allowed bitmask.
7000 * NOTE: the caller must have a valid reference to the task, the
7001 * task must not exit() & deallocate itself prematurely. The
7002 * call is not atomic; no spinlocks may be held.
7004 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
7006 struct migration_req req;
7007 unsigned long flags;
7011 rq = task_rq_lock(p, &flags);
7012 if (!cpumask_intersects(new_mask, cpu_online_mask)) {
7017 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
7018 !cpumask_equal(&p->cpus_allowed, new_mask))) {
7023 if (p->sched_class->set_cpus_allowed)
7024 p->sched_class->set_cpus_allowed(p, new_mask);
7026 cpumask_copy(&p->cpus_allowed, new_mask);
7027 p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
7030 /* Can the task run on the task's current CPU? If so, we're done */
7031 if (cpumask_test_cpu(task_cpu(p), new_mask))
7034 if (migrate_task(p, cpumask_any_and(cpu_online_mask, new_mask), &req)) {
7035 /* Need help from migration thread: drop lock and wait. */
7036 task_rq_unlock(rq, &flags);
7037 wake_up_process(rq->migration_thread);
7038 wait_for_completion(&req.done);
7039 tlb_migrate_finish(p->mm);
7043 task_rq_unlock(rq, &flags);
7047 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
7050 * Move (not current) task off this cpu, onto dest cpu. We're doing
7051 * this because either it can't run here any more (set_cpus_allowed()
7052 * away from this CPU, or CPU going down), or because we're
7053 * attempting to rebalance this task on exec (sched_exec).
7055 * So we race with normal scheduler movements, but that's OK, as long
7056 * as the task is no longer on this CPU.
7058 * Returns non-zero if task was successfully migrated.
7060 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
7062 struct rq *rq_dest, *rq_src;
7065 if (unlikely(!cpu_active(dest_cpu)))
7068 rq_src = cpu_rq(src_cpu);
7069 rq_dest = cpu_rq(dest_cpu);
7071 double_rq_lock(rq_src, rq_dest);
7072 /* Already moved. */
7073 if (task_cpu(p) != src_cpu)
7075 /* Affinity changed (again). */
7076 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
7079 on_rq = p->se.on_rq;
7081 deactivate_task(rq_src, p, 0);
7083 set_task_cpu(p, dest_cpu);
7085 activate_task(rq_dest, p, 0);
7086 check_preempt_curr(rq_dest, p, 0);
7091 double_rq_unlock(rq_src, rq_dest);
7096 * migration_thread - this is a highprio system thread that performs
7097 * thread migration by bumping thread off CPU then 'pushing' onto
7100 static int migration_thread(void *data)
7102 int cpu = (long)data;
7106 BUG_ON(rq->migration_thread != current);
7108 set_current_state(TASK_INTERRUPTIBLE);
7109 while (!kthread_should_stop()) {
7110 struct migration_req *req;
7111 struct list_head *head;
7113 spin_lock_irq(&rq->lock);
7115 if (cpu_is_offline(cpu)) {
7116 spin_unlock_irq(&rq->lock);
7120 if (rq->active_balance) {
7121 active_load_balance(rq, cpu);
7122 rq->active_balance = 0;
7125 head = &rq->migration_queue;
7127 if (list_empty(head)) {
7128 spin_unlock_irq(&rq->lock);
7130 set_current_state(TASK_INTERRUPTIBLE);
7133 req = list_entry(head->next, struct migration_req, list);
7134 list_del_init(head->next);
7136 spin_unlock(&rq->lock);
7137 __migrate_task(req->task, cpu, req->dest_cpu);
7140 complete(&req->done);
7142 __set_current_state(TASK_RUNNING);
7147 #ifdef CONFIG_HOTPLUG_CPU
7149 static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
7153 local_irq_disable();
7154 ret = __migrate_task(p, src_cpu, dest_cpu);
7160 * Figure out where task on dead CPU should go, use force if necessary.
7162 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
7165 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(dead_cpu));
7168 /* Look for allowed, online CPU in same node. */
7169 for_each_cpu_and(dest_cpu, nodemask, cpu_online_mask)
7170 if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
7173 /* Any allowed, online CPU? */
7174 dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_online_mask);
7175 if (dest_cpu < nr_cpu_ids)
7178 /* No more Mr. Nice Guy. */
7179 if (dest_cpu >= nr_cpu_ids) {
7180 cpuset_cpus_allowed_locked(p, &p->cpus_allowed);
7181 dest_cpu = cpumask_any_and(cpu_online_mask, &p->cpus_allowed);
7184 * Don't tell them about moving exiting tasks or
7185 * kernel threads (both mm NULL), since they never
7188 if (p->mm && printk_ratelimit()) {
7189 printk(KERN_INFO "process %d (%s) no "
7190 "longer affine to cpu%d\n",
7191 task_pid_nr(p), p->comm, dead_cpu);
7196 /* It can have affinity changed while we were choosing. */
7197 if (unlikely(!__migrate_task_irq(p, dead_cpu, dest_cpu)))
7202 * While a dead CPU has no uninterruptible tasks queued at this point,
7203 * it might still have a nonzero ->nr_uninterruptible counter, because
7204 * for performance reasons the counter is not stricly tracking tasks to
7205 * their home CPUs. So we just add the counter to another CPU's counter,
7206 * to keep the global sum constant after CPU-down:
7208 static void migrate_nr_uninterruptible(struct rq *rq_src)
7210 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_online_mask));
7211 unsigned long flags;
7213 local_irq_save(flags);
7214 double_rq_lock(rq_src, rq_dest);
7215 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
7216 rq_src->nr_uninterruptible = 0;
7217 double_rq_unlock(rq_src, rq_dest);
7218 local_irq_restore(flags);
7221 /* Run through task list and migrate tasks from the dead cpu. */
7222 static void migrate_live_tasks(int src_cpu)
7224 struct task_struct *p, *t;
7226 read_lock(&tasklist_lock);
7228 do_each_thread(t, p) {
7232 if (task_cpu(p) == src_cpu)
7233 move_task_off_dead_cpu(src_cpu, p);
7234 } while_each_thread(t, p);
7236 read_unlock(&tasklist_lock);
7240 * Schedules idle task to be the next runnable task on current CPU.
7241 * It does so by boosting its priority to highest possible.
7242 * Used by CPU offline code.
7244 void sched_idle_next(void)
7246 int this_cpu = smp_processor_id();
7247 struct rq *rq = cpu_rq(this_cpu);
7248 struct task_struct *p = rq->idle;
7249 unsigned long flags;
7251 /* cpu has to be offline */
7252 BUG_ON(cpu_online(this_cpu));
7255 * Strictly not necessary since rest of the CPUs are stopped by now
7256 * and interrupts disabled on the current cpu.
7258 spin_lock_irqsave(&rq->lock, flags);
7260 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
7262 update_rq_clock(rq);
7263 activate_task(rq, p, 0);
7265 spin_unlock_irqrestore(&rq->lock, flags);
7269 * Ensures that the idle task is using init_mm right before its cpu goes
7272 void idle_task_exit(void)
7274 struct mm_struct *mm = current->active_mm;
7276 BUG_ON(cpu_online(smp_processor_id()));
7279 switch_mm(mm, &init_mm, current);
7283 /* called under rq->lock with disabled interrupts */
7284 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
7286 struct rq *rq = cpu_rq(dead_cpu);
7288 /* Must be exiting, otherwise would be on tasklist. */
7289 BUG_ON(!p->exit_state);
7291 /* Cannot have done final schedule yet: would have vanished. */
7292 BUG_ON(p->state == TASK_DEAD);
7297 * Drop lock around migration; if someone else moves it,
7298 * that's OK. No task can be added to this CPU, so iteration is
7301 spin_unlock_irq(&rq->lock);
7302 move_task_off_dead_cpu(dead_cpu, p);
7303 spin_lock_irq(&rq->lock);
7308 /* release_task() removes task from tasklist, so we won't find dead tasks. */
7309 static void migrate_dead_tasks(unsigned int dead_cpu)
7311 struct rq *rq = cpu_rq(dead_cpu);
7312 struct task_struct *next;
7315 if (!rq->nr_running)
7317 update_rq_clock(rq);
7318 next = pick_next_task(rq);
7321 next->sched_class->put_prev_task(rq, next);
7322 migrate_dead(dead_cpu, next);
7328 * remove the tasks which were accounted by rq from calc_load_tasks.
7330 static void calc_global_load_remove(struct rq *rq)
7332 atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
7333 rq->calc_load_active = 0;
7335 #endif /* CONFIG_HOTPLUG_CPU */
7337 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
7339 static struct ctl_table sd_ctl_dir[] = {
7341 .procname = "sched_domain",
7347 static struct ctl_table sd_ctl_root[] = {
7349 .ctl_name = CTL_KERN,
7350 .procname = "kernel",
7352 .child = sd_ctl_dir,
7357 static struct ctl_table *sd_alloc_ctl_entry(int n)
7359 struct ctl_table *entry =
7360 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
7365 static void sd_free_ctl_entry(struct ctl_table **tablep)
7367 struct ctl_table *entry;
7370 * In the intermediate directories, both the child directory and
7371 * procname are dynamically allocated and could fail but the mode
7372 * will always be set. In the lowest directory the names are
7373 * static strings and all have proc handlers.
7375 for (entry = *tablep; entry->mode; entry++) {
7377 sd_free_ctl_entry(&entry->child);
7378 if (entry->proc_handler == NULL)
7379 kfree(entry->procname);
7387 set_table_entry(struct ctl_table *entry,
7388 const char *procname, void *data, int maxlen,
7389 mode_t mode, proc_handler *proc_handler)
7391 entry->procname = procname;
7393 entry->maxlen = maxlen;
7395 entry->proc_handler = proc_handler;
7398 static struct ctl_table *
7399 sd_alloc_ctl_domain_table(struct sched_domain *sd)
7401 struct ctl_table *table = sd_alloc_ctl_entry(13);
7406 set_table_entry(&table[0], "min_interval", &sd->min_interval,
7407 sizeof(long), 0644, proc_doulongvec_minmax);
7408 set_table_entry(&table[1], "max_interval", &sd->max_interval,
7409 sizeof(long), 0644, proc_doulongvec_minmax);
7410 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
7411 sizeof(int), 0644, proc_dointvec_minmax);
7412 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
7413 sizeof(int), 0644, proc_dointvec_minmax);
7414 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
7415 sizeof(int), 0644, proc_dointvec_minmax);
7416 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
7417 sizeof(int), 0644, proc_dointvec_minmax);
7418 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
7419 sizeof(int), 0644, proc_dointvec_minmax);
7420 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
7421 sizeof(int), 0644, proc_dointvec_minmax);
7422 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
7423 sizeof(int), 0644, proc_dointvec_minmax);
7424 set_table_entry(&table[9], "cache_nice_tries",
7425 &sd->cache_nice_tries,
7426 sizeof(int), 0644, proc_dointvec_minmax);
7427 set_table_entry(&table[10], "flags", &sd->flags,
7428 sizeof(int), 0644, proc_dointvec_minmax);
7429 set_table_entry(&table[11], "name", sd->name,
7430 CORENAME_MAX_SIZE, 0444, proc_dostring);
7431 /* &table[12] is terminator */
7436 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
7438 struct ctl_table *entry, *table;
7439 struct sched_domain *sd;
7440 int domain_num = 0, i;
7443 for_each_domain(cpu, sd)
7445 entry = table = sd_alloc_ctl_entry(domain_num + 1);
7450 for_each_domain(cpu, sd) {
7451 snprintf(buf, 32, "domain%d", i);
7452 entry->procname = kstrdup(buf, GFP_KERNEL);
7454 entry->child = sd_alloc_ctl_domain_table(sd);
7461 static struct ctl_table_header *sd_sysctl_header;
7462 static void register_sched_domain_sysctl(void)
7464 int i, cpu_num = num_online_cpus();
7465 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
7468 WARN_ON(sd_ctl_dir[0].child);
7469 sd_ctl_dir[0].child = entry;
7474 for_each_online_cpu(i) {
7475 snprintf(buf, 32, "cpu%d", i);
7476 entry->procname = kstrdup(buf, GFP_KERNEL);
7478 entry->child = sd_alloc_ctl_cpu_table(i);
7482 WARN_ON(sd_sysctl_header);
7483 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
7486 /* may be called multiple times per register */
7487 static void unregister_sched_domain_sysctl(void)
7489 if (sd_sysctl_header)
7490 unregister_sysctl_table(sd_sysctl_header);
7491 sd_sysctl_header = NULL;
7492 if (sd_ctl_dir[0].child)
7493 sd_free_ctl_entry(&sd_ctl_dir[0].child);
7496 static void register_sched_domain_sysctl(void)
7499 static void unregister_sched_domain_sysctl(void)
7504 static void set_rq_online(struct rq *rq)
7507 const struct sched_class *class;
7509 cpumask_set_cpu(rq->cpu, rq->rd->online);
7512 for_each_class(class) {
7513 if (class->rq_online)
7514 class->rq_online(rq);
7519 static void set_rq_offline(struct rq *rq)
7522 const struct sched_class *class;
7524 for_each_class(class) {
7525 if (class->rq_offline)
7526 class->rq_offline(rq);
7529 cpumask_clear_cpu(rq->cpu, rq->rd->online);
7535 * migration_call - callback that gets triggered when a CPU is added.
7536 * Here we can start up the necessary migration thread for the new CPU.
7538 static int __cpuinit
7539 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
7541 struct task_struct *p;
7542 int cpu = (long)hcpu;
7543 unsigned long flags;
7548 case CPU_UP_PREPARE:
7549 case CPU_UP_PREPARE_FROZEN:
7550 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
7553 kthread_bind(p, cpu);
7554 /* Must be high prio: stop_machine expects to yield to it. */
7555 rq = task_rq_lock(p, &flags);
7556 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
7557 task_rq_unlock(rq, &flags);
7559 cpu_rq(cpu)->migration_thread = p;
7560 rq->calc_load_update = calc_load_update;
7564 case CPU_ONLINE_FROZEN:
7565 /* Strictly unnecessary, as first user will wake it. */
7566 wake_up_process(cpu_rq(cpu)->migration_thread);
7568 /* Update our root-domain */
7570 spin_lock_irqsave(&rq->lock, flags);
7572 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
7576 spin_unlock_irqrestore(&rq->lock, flags);
7579 #ifdef CONFIG_HOTPLUG_CPU
7580 case CPU_UP_CANCELED:
7581 case CPU_UP_CANCELED_FROZEN:
7582 if (!cpu_rq(cpu)->migration_thread)
7584 /* Unbind it from offline cpu so it can run. Fall thru. */
7585 kthread_bind(cpu_rq(cpu)->migration_thread,
7586 cpumask_any(cpu_online_mask));
7587 kthread_stop(cpu_rq(cpu)->migration_thread);
7588 put_task_struct(cpu_rq(cpu)->migration_thread);
7589 cpu_rq(cpu)->migration_thread = NULL;
7593 case CPU_DEAD_FROZEN:
7594 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7595 migrate_live_tasks(cpu);
7597 kthread_stop(rq->migration_thread);
7598 put_task_struct(rq->migration_thread);
7599 rq->migration_thread = NULL;
7600 /* Idle task back to normal (off runqueue, low prio) */
7601 spin_lock_irq(&rq->lock);
7602 update_rq_clock(rq);
7603 deactivate_task(rq, rq->idle, 0);
7604 rq->idle->static_prio = MAX_PRIO;
7605 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
7606 rq->idle->sched_class = &idle_sched_class;
7607 migrate_dead_tasks(cpu);
7608 spin_unlock_irq(&rq->lock);
7610 migrate_nr_uninterruptible(rq);
7611 BUG_ON(rq->nr_running != 0);
7612 calc_global_load_remove(rq);
7614 * No need to migrate the tasks: it was best-effort if
7615 * they didn't take sched_hotcpu_mutex. Just wake up
7618 spin_lock_irq(&rq->lock);
7619 while (!list_empty(&rq->migration_queue)) {
7620 struct migration_req *req;
7622 req = list_entry(rq->migration_queue.next,
7623 struct migration_req, list);
7624 list_del_init(&req->list);
7625 spin_unlock_irq(&rq->lock);
7626 complete(&req->done);
7627 spin_lock_irq(&rq->lock);
7629 spin_unlock_irq(&rq->lock);
7633 case CPU_DYING_FROZEN:
7634 /* Update our root-domain */
7636 spin_lock_irqsave(&rq->lock, flags);
7638 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
7641 spin_unlock_irqrestore(&rq->lock, flags);
7649 * Register at high priority so that task migration (migrate_all_tasks)
7650 * happens before everything else. This has to be lower priority than
7651 * the notifier in the perf_counter subsystem, though.
7653 static struct notifier_block __cpuinitdata migration_notifier = {
7654 .notifier_call = migration_call,
7658 static int __init migration_init(void)
7660 void *cpu = (void *)(long)smp_processor_id();
7663 /* Start one for the boot CPU: */
7664 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
7665 BUG_ON(err == NOTIFY_BAD);
7666 migration_call(&migration_notifier, CPU_ONLINE, cpu);
7667 register_cpu_notifier(&migration_notifier);
7671 early_initcall(migration_init);
7676 #ifdef CONFIG_SCHED_DEBUG
7678 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
7679 struct cpumask *groupmask)
7681 struct sched_group *group = sd->groups;
7684 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
7685 cpumask_clear(groupmask);
7687 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
7689 if (!(sd->flags & SD_LOAD_BALANCE)) {
7690 printk("does not load-balance\n");
7692 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
7697 printk(KERN_CONT "span %s level %s\n", str, sd->name);
7699 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
7700 printk(KERN_ERR "ERROR: domain->span does not contain "
7703 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
7704 printk(KERN_ERR "ERROR: domain->groups does not contain"
7708 printk(KERN_DEBUG "%*s groups:", level + 1, "");
7712 printk(KERN_ERR "ERROR: group is NULL\n");
7716 if (!group->__cpu_power) {
7717 printk(KERN_CONT "\n");
7718 printk(KERN_ERR "ERROR: domain->cpu_power not "
7723 if (!cpumask_weight(sched_group_cpus(group))) {
7724 printk(KERN_CONT "\n");
7725 printk(KERN_ERR "ERROR: empty group\n");
7729 if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
7730 printk(KERN_CONT "\n");
7731 printk(KERN_ERR "ERROR: repeated CPUs\n");
7735 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
7737 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
7739 printk(KERN_CONT " %s", str);
7740 if (group->__cpu_power != SCHED_LOAD_SCALE) {
7741 printk(KERN_CONT " (__cpu_power = %d)",
7742 group->__cpu_power);
7745 group = group->next;
7746 } while (group != sd->groups);
7747 printk(KERN_CONT "\n");
7749 if (!cpumask_equal(sched_domain_span(sd), groupmask))
7750 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
7753 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
7754 printk(KERN_ERR "ERROR: parent span is not a superset "
7755 "of domain->span\n");
7759 static void sched_domain_debug(struct sched_domain *sd, int cpu)
7761 cpumask_var_t groupmask;
7765 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
7769 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
7771 if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) {
7772 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
7777 if (sched_domain_debug_one(sd, cpu, level, groupmask))
7784 free_cpumask_var(groupmask);
7786 #else /* !CONFIG_SCHED_DEBUG */
7787 # define sched_domain_debug(sd, cpu) do { } while (0)
7788 #endif /* CONFIG_SCHED_DEBUG */
7790 static int sd_degenerate(struct sched_domain *sd)
7792 if (cpumask_weight(sched_domain_span(sd)) == 1)
7795 /* Following flags need at least 2 groups */
7796 if (sd->flags & (SD_LOAD_BALANCE |
7797 SD_BALANCE_NEWIDLE |
7801 SD_SHARE_PKG_RESOURCES)) {
7802 if (sd->groups != sd->groups->next)
7806 /* Following flags don't use groups */
7807 if (sd->flags & (SD_WAKE_IDLE |
7816 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
7818 unsigned long cflags = sd->flags, pflags = parent->flags;
7820 if (sd_degenerate(parent))
7823 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
7826 /* Does parent contain flags not in child? */
7827 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7828 if (cflags & SD_WAKE_AFFINE)
7829 pflags &= ~SD_WAKE_BALANCE;
7830 /* Flags needing groups don't count if only 1 group in parent */
7831 if (parent->groups == parent->groups->next) {
7832 pflags &= ~(SD_LOAD_BALANCE |
7833 SD_BALANCE_NEWIDLE |
7837 SD_SHARE_PKG_RESOURCES);
7838 if (nr_node_ids == 1)
7839 pflags &= ~SD_SERIALIZE;
7841 if (~cflags & pflags)
7847 static void free_rootdomain(struct root_domain *rd)
7849 cpupri_cleanup(&rd->cpupri);
7851 free_cpumask_var(rd->rto_mask);
7852 free_cpumask_var(rd->online);
7853 free_cpumask_var(rd->span);
7857 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
7859 struct root_domain *old_rd = NULL;
7860 unsigned long flags;
7862 spin_lock_irqsave(&rq->lock, flags);
7867 if (cpumask_test_cpu(rq->cpu, old_rd->online))
7870 cpumask_clear_cpu(rq->cpu, old_rd->span);
7873 * If we dont want to free the old_rt yet then
7874 * set old_rd to NULL to skip the freeing later
7877 if (!atomic_dec_and_test(&old_rd->refcount))
7881 atomic_inc(&rd->refcount);
7884 cpumask_set_cpu(rq->cpu, rd->span);
7885 if (cpumask_test_cpu(rq->cpu, cpu_online_mask))
7888 spin_unlock_irqrestore(&rq->lock, flags);
7891 free_rootdomain(old_rd);
7894 static int init_rootdomain(struct root_domain *rd, bool bootmem)
7896 gfp_t gfp = GFP_KERNEL;
7898 memset(rd, 0, sizeof(*rd));
7903 if (!alloc_cpumask_var(&rd->span, gfp))
7905 if (!alloc_cpumask_var(&rd->online, gfp))
7907 if (!alloc_cpumask_var(&rd->rto_mask, gfp))
7910 if (cpupri_init(&rd->cpupri, bootmem) != 0)
7915 free_cpumask_var(rd->rto_mask);
7917 free_cpumask_var(rd->online);
7919 free_cpumask_var(rd->span);
7924 static void init_defrootdomain(void)
7926 init_rootdomain(&def_root_domain, true);
7928 atomic_set(&def_root_domain.refcount, 1);
7931 static struct root_domain *alloc_rootdomain(void)
7933 struct root_domain *rd;
7935 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
7939 if (init_rootdomain(rd, false) != 0) {
7948 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7949 * hold the hotplug lock.
7952 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
7954 struct rq *rq = cpu_rq(cpu);
7955 struct sched_domain *tmp;
7957 /* Remove the sched domains which do not contribute to scheduling. */
7958 for (tmp = sd; tmp; ) {
7959 struct sched_domain *parent = tmp->parent;
7963 if (sd_parent_degenerate(tmp, parent)) {
7964 tmp->parent = parent->parent;
7966 parent->parent->child = tmp;
7971 if (sd && sd_degenerate(sd)) {
7977 sched_domain_debug(sd, cpu);
7979 rq_attach_root(rq, rd);
7980 rcu_assign_pointer(rq->sd, sd);
7983 /* cpus with isolated domains */
7984 static cpumask_var_t cpu_isolated_map;
7986 /* Setup the mask of cpus configured for isolated domains */
7987 static int __init isolated_cpu_setup(char *str)
7989 cpulist_parse(str, cpu_isolated_map);
7993 __setup("isolcpus=", isolated_cpu_setup);
7996 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7997 * to a function which identifies what group(along with sched group) a CPU
7998 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7999 * (due to the fact that we keep track of groups covered with a struct cpumask).
8001 * init_sched_build_groups will build a circular linked list of the groups
8002 * covered by the given span, and will set each group's ->cpumask correctly,
8003 * and ->cpu_power to 0.
8006 init_sched_build_groups(const struct cpumask *span,
8007 const struct cpumask *cpu_map,
8008 int (*group_fn)(int cpu, const struct cpumask *cpu_map,
8009 struct sched_group **sg,
8010 struct cpumask *tmpmask),
8011 struct cpumask *covered, struct cpumask *tmpmask)
8013 struct sched_group *first = NULL, *last = NULL;
8016 cpumask_clear(covered);
8018 for_each_cpu(i, span) {
8019 struct sched_group *sg;
8020 int group = group_fn(i, cpu_map, &sg, tmpmask);
8023 if (cpumask_test_cpu(i, covered))
8026 cpumask_clear(sched_group_cpus(sg));
8027 sg->__cpu_power = 0;
8029 for_each_cpu(j, span) {
8030 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
8033 cpumask_set_cpu(j, covered);
8034 cpumask_set_cpu(j, sched_group_cpus(sg));
8045 #define SD_NODES_PER_DOMAIN 16
8050 * find_next_best_node - find the next node to include in a sched_domain
8051 * @node: node whose sched_domain we're building
8052 * @used_nodes: nodes already in the sched_domain
8054 * Find the next node to include in a given scheduling domain. Simply
8055 * finds the closest node not already in the @used_nodes map.
8057 * Should use nodemask_t.
8059 static int find_next_best_node(int node, nodemask_t *used_nodes)
8061 int i, n, val, min_val, best_node = 0;
8065 for (i = 0; i < nr_node_ids; i++) {
8066 /* Start at @node */
8067 n = (node + i) % nr_node_ids;
8069 if (!nr_cpus_node(n))
8072 /* Skip already used nodes */
8073 if (node_isset(n, *used_nodes))
8076 /* Simple min distance search */
8077 val = node_distance(node, n);
8079 if (val < min_val) {
8085 node_set(best_node, *used_nodes);
8090 * sched_domain_node_span - get a cpumask for a node's sched_domain
8091 * @node: node whose cpumask we're constructing
8092 * @span: resulting cpumask
8094 * Given a node, construct a good cpumask for its sched_domain to span. It
8095 * should be one that prevents unnecessary balancing, but also spreads tasks
8098 static void sched_domain_node_span(int node, struct cpumask *span)
8100 nodemask_t used_nodes;
8103 cpumask_clear(span);
8104 nodes_clear(used_nodes);
8106 cpumask_or(span, span, cpumask_of_node(node));
8107 node_set(node, used_nodes);
8109 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
8110 int next_node = find_next_best_node(node, &used_nodes);
8112 cpumask_or(span, span, cpumask_of_node(next_node));
8115 #endif /* CONFIG_NUMA */
8117 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
8120 * The cpus mask in sched_group and sched_domain hangs off the end.
8122 * ( See the the comments in include/linux/sched.h:struct sched_group
8123 * and struct sched_domain. )
8125 struct static_sched_group {
8126 struct sched_group sg;
8127 DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
8130 struct static_sched_domain {
8131 struct sched_domain sd;
8132 DECLARE_BITMAP(span, CONFIG_NR_CPUS);
8136 * SMT sched-domains:
8138 #ifdef CONFIG_SCHED_SMT
8139 static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
8140 static DEFINE_PER_CPU(struct static_sched_group, sched_group_cpus);
8143 cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map,
8144 struct sched_group **sg, struct cpumask *unused)
8147 *sg = &per_cpu(sched_group_cpus, cpu).sg;
8150 #endif /* CONFIG_SCHED_SMT */
8153 * multi-core sched-domains:
8155 #ifdef CONFIG_SCHED_MC
8156 static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
8157 static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
8158 #endif /* CONFIG_SCHED_MC */
8160 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
8162 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
8163 struct sched_group **sg, struct cpumask *mask)
8167 cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
8168 group = cpumask_first(mask);
8170 *sg = &per_cpu(sched_group_core, group).sg;
8173 #elif defined(CONFIG_SCHED_MC)
8175 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
8176 struct sched_group **sg, struct cpumask *unused)
8179 *sg = &per_cpu(sched_group_core, cpu).sg;
8184 static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
8185 static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
8188 cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
8189 struct sched_group **sg, struct cpumask *mask)
8192 #ifdef CONFIG_SCHED_MC
8193 cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
8194 group = cpumask_first(mask);
8195 #elif defined(CONFIG_SCHED_SMT)
8196 cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
8197 group = cpumask_first(mask);
8202 *sg = &per_cpu(sched_group_phys, group).sg;
8208 * The init_sched_build_groups can't handle what we want to do with node
8209 * groups, so roll our own. Now each node has its own list of groups which
8210 * gets dynamically allocated.
8212 static DEFINE_PER_CPU(struct static_sched_domain, node_domains);
8213 static struct sched_group ***sched_group_nodes_bycpu;
8215 static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
8216 static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
8218 static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
8219 struct sched_group **sg,
8220 struct cpumask *nodemask)
8224 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map);
8225 group = cpumask_first(nodemask);
8228 *sg = &per_cpu(sched_group_allnodes, group).sg;
8232 static void init_numa_sched_groups_power(struct sched_group *group_head)
8234 struct sched_group *sg = group_head;
8240 for_each_cpu(j, sched_group_cpus(sg)) {
8241 struct sched_domain *sd;
8243 sd = &per_cpu(phys_domains, j).sd;
8244 if (j != group_first_cpu(sd->groups)) {
8246 * Only add "power" once for each
8252 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
8255 } while (sg != group_head);
8257 #endif /* CONFIG_NUMA */
8260 /* Free memory allocated for various sched_group structures */
8261 static void free_sched_groups(const struct cpumask *cpu_map,
8262 struct cpumask *nodemask)
8266 for_each_cpu(cpu, cpu_map) {
8267 struct sched_group **sched_group_nodes
8268 = sched_group_nodes_bycpu[cpu];
8270 if (!sched_group_nodes)
8273 for (i = 0; i < nr_node_ids; i++) {
8274 struct sched_group *oldsg, *sg = sched_group_nodes[i];
8276 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
8277 if (cpumask_empty(nodemask))
8287 if (oldsg != sched_group_nodes[i])
8290 kfree(sched_group_nodes);
8291 sched_group_nodes_bycpu[cpu] = NULL;
8294 #else /* !CONFIG_NUMA */
8295 static void free_sched_groups(const struct cpumask *cpu_map,
8296 struct cpumask *nodemask)
8299 #endif /* CONFIG_NUMA */
8302 * Initialize sched groups cpu_power.
8304 * cpu_power indicates the capacity of sched group, which is used while
8305 * distributing the load between different sched groups in a sched domain.
8306 * Typically cpu_power for all the groups in a sched domain will be same unless
8307 * there are asymmetries in the topology. If there are asymmetries, group
8308 * having more cpu_power will pickup more load compared to the group having
8311 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
8312 * the maximum number of tasks a group can handle in the presence of other idle
8313 * or lightly loaded groups in the same sched domain.
8315 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
8317 struct sched_domain *child;
8318 struct sched_group *group;
8320 WARN_ON(!sd || !sd->groups);
8322 if (cpu != group_first_cpu(sd->groups))
8327 sd->groups->__cpu_power = 0;
8330 * For perf policy, if the groups in child domain share resources
8331 * (for example cores sharing some portions of the cache hierarchy
8332 * or SMT), then set this domain groups cpu_power such that each group
8333 * can handle only one task, when there are other idle groups in the
8334 * same sched domain.
8336 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
8338 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
8339 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
8344 * add cpu_power of each child group to this groups cpu_power
8346 group = child->groups;
8348 sg_inc_cpu_power(sd->groups, group->__cpu_power);
8349 group = group->next;
8350 } while (group != child->groups);
8354 * Initializers for schedule domains
8355 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
8358 #ifdef CONFIG_SCHED_DEBUG
8359 # define SD_INIT_NAME(sd, type) sd->name = #type
8361 # define SD_INIT_NAME(sd, type) do { } while (0)
8364 #define SD_INIT(sd, type) sd_init_##type(sd)
8366 #define SD_INIT_FUNC(type) \
8367 static noinline void sd_init_##type(struct sched_domain *sd) \
8369 memset(sd, 0, sizeof(*sd)); \
8370 *sd = SD_##type##_INIT; \
8371 sd->level = SD_LV_##type; \
8372 SD_INIT_NAME(sd, type); \
8377 SD_INIT_FUNC(ALLNODES)
8380 #ifdef CONFIG_SCHED_SMT
8381 SD_INIT_FUNC(SIBLING)
8383 #ifdef CONFIG_SCHED_MC
8387 static int default_relax_domain_level = -1;
8389 static int __init setup_relax_domain_level(char *str)
8393 val = simple_strtoul(str, NULL, 0);
8394 if (val < SD_LV_MAX)
8395 default_relax_domain_level = val;
8399 __setup("relax_domain_level=", setup_relax_domain_level);
8401 static void set_domain_attribute(struct sched_domain *sd,
8402 struct sched_domain_attr *attr)
8406 if (!attr || attr->relax_domain_level < 0) {
8407 if (default_relax_domain_level < 0)
8410 request = default_relax_domain_level;
8412 request = attr->relax_domain_level;
8413 if (request < sd->level) {
8414 /* turn off idle balance on this domain */
8415 sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
8417 /* turn on idle balance on this domain */
8418 sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
8423 * Build sched domains for a given set of cpus and attach the sched domains
8424 * to the individual cpus
8426 static int __build_sched_domains(const struct cpumask *cpu_map,
8427 struct sched_domain_attr *attr)
8429 int i, err = -ENOMEM;
8430 struct root_domain *rd;
8431 cpumask_var_t nodemask, this_sibling_map, this_core_map, send_covered,
8434 cpumask_var_t domainspan, covered, notcovered;
8435 struct sched_group **sched_group_nodes = NULL;
8436 int sd_allnodes = 0;
8438 if (!alloc_cpumask_var(&domainspan, GFP_KERNEL))
8440 if (!alloc_cpumask_var(&covered, GFP_KERNEL))
8441 goto free_domainspan;
8442 if (!alloc_cpumask_var(¬covered, GFP_KERNEL))
8446 if (!alloc_cpumask_var(&nodemask, GFP_KERNEL))
8447 goto free_notcovered;
8448 if (!alloc_cpumask_var(&this_sibling_map, GFP_KERNEL))
8450 if (!alloc_cpumask_var(&this_core_map, GFP_KERNEL))
8451 goto free_this_sibling_map;
8452 if (!alloc_cpumask_var(&send_covered, GFP_KERNEL))
8453 goto free_this_core_map;
8454 if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
8455 goto free_send_covered;
8459 * Allocate the per-node list of sched groups
8461 sched_group_nodes = kcalloc(nr_node_ids, sizeof(struct sched_group *),
8463 if (!sched_group_nodes) {
8464 printk(KERN_WARNING "Can not alloc sched group node list\n");
8469 rd = alloc_rootdomain();
8471 printk(KERN_WARNING "Cannot alloc root domain\n");
8472 goto free_sched_groups;
8476 sched_group_nodes_bycpu[cpumask_first(cpu_map)] = sched_group_nodes;
8480 * Set up domains for cpus specified by the cpu_map.
8482 for_each_cpu(i, cpu_map) {
8483 struct sched_domain *sd = NULL, *p;
8485 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(i)), cpu_map);
8488 if (cpumask_weight(cpu_map) >
8489 SD_NODES_PER_DOMAIN*cpumask_weight(nodemask)) {
8490 sd = &per_cpu(allnodes_domains, i).sd;
8491 SD_INIT(sd, ALLNODES);
8492 set_domain_attribute(sd, attr);
8493 cpumask_copy(sched_domain_span(sd), cpu_map);
8494 cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
8500 sd = &per_cpu(node_domains, i).sd;
8502 set_domain_attribute(sd, attr);
8503 sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd));
8507 cpumask_and(sched_domain_span(sd),
8508 sched_domain_span(sd), cpu_map);
8512 sd = &per_cpu(phys_domains, i).sd;
8514 set_domain_attribute(sd, attr);
8515 cpumask_copy(sched_domain_span(sd), nodemask);
8519 cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
8521 #ifdef CONFIG_SCHED_MC
8523 sd = &per_cpu(core_domains, i).sd;
8525 set_domain_attribute(sd, attr);
8526 cpumask_and(sched_domain_span(sd), cpu_map,
8527 cpu_coregroup_mask(i));
8530 cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
8533 #ifdef CONFIG_SCHED_SMT
8535 sd = &per_cpu(cpu_domains, i).sd;
8536 SD_INIT(sd, SIBLING);
8537 set_domain_attribute(sd, attr);
8538 cpumask_and(sched_domain_span(sd),
8539 topology_thread_cpumask(i), cpu_map);
8542 cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
8546 #ifdef CONFIG_SCHED_SMT
8547 /* Set up CPU (sibling) groups */
8548 for_each_cpu(i, cpu_map) {
8549 cpumask_and(this_sibling_map,
8550 topology_thread_cpumask(i), cpu_map);
8551 if (i != cpumask_first(this_sibling_map))
8554 init_sched_build_groups(this_sibling_map, cpu_map,
8556 send_covered, tmpmask);
8560 #ifdef CONFIG_SCHED_MC
8561 /* Set up multi-core groups */
8562 for_each_cpu(i, cpu_map) {
8563 cpumask_and(this_core_map, cpu_coregroup_mask(i), cpu_map);
8564 if (i != cpumask_first(this_core_map))
8567 init_sched_build_groups(this_core_map, cpu_map,
8569 send_covered, tmpmask);
8573 /* Set up physical groups */
8574 for (i = 0; i < nr_node_ids; i++) {
8575 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
8576 if (cpumask_empty(nodemask))
8579 init_sched_build_groups(nodemask, cpu_map,
8581 send_covered, tmpmask);
8585 /* Set up node groups */
8587 init_sched_build_groups(cpu_map, cpu_map,
8588 &cpu_to_allnodes_group,
8589 send_covered, tmpmask);
8592 for (i = 0; i < nr_node_ids; i++) {
8593 /* Set up node groups */
8594 struct sched_group *sg, *prev;
8597 cpumask_clear(covered);
8598 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
8599 if (cpumask_empty(nodemask)) {
8600 sched_group_nodes[i] = NULL;
8604 sched_domain_node_span(i, domainspan);
8605 cpumask_and(domainspan, domainspan, cpu_map);
8607 sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
8610 printk(KERN_WARNING "Can not alloc domain group for "
8614 sched_group_nodes[i] = sg;
8615 for_each_cpu(j, nodemask) {
8616 struct sched_domain *sd;
8618 sd = &per_cpu(node_domains, j).sd;
8621 sg->__cpu_power = 0;
8622 cpumask_copy(sched_group_cpus(sg), nodemask);
8624 cpumask_or(covered, covered, nodemask);
8627 for (j = 0; j < nr_node_ids; j++) {
8628 int n = (i + j) % nr_node_ids;
8630 cpumask_complement(notcovered, covered);
8631 cpumask_and(tmpmask, notcovered, cpu_map);
8632 cpumask_and(tmpmask, tmpmask, domainspan);
8633 if (cpumask_empty(tmpmask))
8636 cpumask_and(tmpmask, tmpmask, cpumask_of_node(n));
8637 if (cpumask_empty(tmpmask))
8640 sg = kmalloc_node(sizeof(struct sched_group) +
8645 "Can not alloc domain group for node %d\n", j);
8648 sg->__cpu_power = 0;
8649 cpumask_copy(sched_group_cpus(sg), tmpmask);
8650 sg->next = prev->next;
8651 cpumask_or(covered, covered, tmpmask);
8658 /* Calculate CPU power for physical packages and nodes */
8659 #ifdef CONFIG_SCHED_SMT
8660 for_each_cpu(i, cpu_map) {
8661 struct sched_domain *sd = &per_cpu(cpu_domains, i).sd;
8663 init_sched_groups_power(i, sd);
8666 #ifdef CONFIG_SCHED_MC
8667 for_each_cpu(i, cpu_map) {
8668 struct sched_domain *sd = &per_cpu(core_domains, i).sd;
8670 init_sched_groups_power(i, sd);
8674 for_each_cpu(i, cpu_map) {
8675 struct sched_domain *sd = &per_cpu(phys_domains, i).sd;
8677 init_sched_groups_power(i, sd);
8681 for (i = 0; i < nr_node_ids; i++)
8682 init_numa_sched_groups_power(sched_group_nodes[i]);
8685 struct sched_group *sg;
8687 cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg,
8689 init_numa_sched_groups_power(sg);
8693 /* Attach the domains */
8694 for_each_cpu(i, cpu_map) {
8695 struct sched_domain *sd;
8696 #ifdef CONFIG_SCHED_SMT
8697 sd = &per_cpu(cpu_domains, i).sd;
8698 #elif defined(CONFIG_SCHED_MC)
8699 sd = &per_cpu(core_domains, i).sd;
8701 sd = &per_cpu(phys_domains, i).sd;
8703 cpu_attach_domain(sd, rd, i);
8709 free_cpumask_var(tmpmask);
8711 free_cpumask_var(send_covered);
8713 free_cpumask_var(this_core_map);
8714 free_this_sibling_map:
8715 free_cpumask_var(this_sibling_map);
8717 free_cpumask_var(nodemask);
8720 free_cpumask_var(notcovered);
8722 free_cpumask_var(covered);
8724 free_cpumask_var(domainspan);
8731 kfree(sched_group_nodes);
8737 free_sched_groups(cpu_map, tmpmask);
8738 free_rootdomain(rd);
8743 static int build_sched_domains(const struct cpumask *cpu_map)
8745 return __build_sched_domains(cpu_map, NULL);
8748 static struct cpumask *doms_cur; /* current sched domains */
8749 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
8750 static struct sched_domain_attr *dattr_cur;
8751 /* attribues of custom domains in 'doms_cur' */
8754 * Special case: If a kmalloc of a doms_cur partition (array of
8755 * cpumask) fails, then fallback to a single sched domain,
8756 * as determined by the single cpumask fallback_doms.
8758 static cpumask_var_t fallback_doms;
8761 * arch_update_cpu_topology lets virtualized architectures update the
8762 * cpu core maps. It is supposed to return 1 if the topology changed
8763 * or 0 if it stayed the same.
8765 int __attribute__((weak)) arch_update_cpu_topology(void)
8771 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8772 * For now this just excludes isolated cpus, but could be used to
8773 * exclude other special cases in the future.
8775 static int arch_init_sched_domains(const struct cpumask *cpu_map)
8779 arch_update_cpu_topology();
8781 doms_cur = kmalloc(cpumask_size(), GFP_KERNEL);
8783 doms_cur = fallback_doms;
8784 cpumask_andnot(doms_cur, cpu_map, cpu_isolated_map);
8786 err = build_sched_domains(doms_cur);
8787 register_sched_domain_sysctl();
8792 static void arch_destroy_sched_domains(const struct cpumask *cpu_map,
8793 struct cpumask *tmpmask)
8795 free_sched_groups(cpu_map, tmpmask);
8799 * Detach sched domains from a group of cpus specified in cpu_map
8800 * These cpus will now be attached to the NULL domain
8802 static void detach_destroy_domains(const struct cpumask *cpu_map)
8804 /* Save because hotplug lock held. */
8805 static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS);
8808 for_each_cpu(i, cpu_map)
8809 cpu_attach_domain(NULL, &def_root_domain, i);
8810 synchronize_sched();
8811 arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask));
8814 /* handle null as "default" */
8815 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
8816 struct sched_domain_attr *new, int idx_new)
8818 struct sched_domain_attr tmp;
8825 return !memcmp(cur ? (cur + idx_cur) : &tmp,
8826 new ? (new + idx_new) : &tmp,
8827 sizeof(struct sched_domain_attr));
8831 * Partition sched domains as specified by the 'ndoms_new'
8832 * cpumasks in the array doms_new[] of cpumasks. This compares
8833 * doms_new[] to the current sched domain partitioning, doms_cur[].
8834 * It destroys each deleted domain and builds each new domain.
8836 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8837 * The masks don't intersect (don't overlap.) We should setup one
8838 * sched domain for each mask. CPUs not in any of the cpumasks will
8839 * not be load balanced. If the same cpumask appears both in the
8840 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8843 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8844 * ownership of it and will kfree it when done with it. If the caller
8845 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8846 * ndoms_new == 1, and partition_sched_domains() will fallback to
8847 * the single partition 'fallback_doms', it also forces the domains
8850 * If doms_new == NULL it will be replaced with cpu_online_mask.
8851 * ndoms_new == 0 is a special case for destroying existing domains,
8852 * and it will not create the default domain.
8854 * Call with hotplug lock held
8856 /* FIXME: Change to struct cpumask *doms_new[] */
8857 void partition_sched_domains(int ndoms_new, struct cpumask *doms_new,
8858 struct sched_domain_attr *dattr_new)
8863 mutex_lock(&sched_domains_mutex);
8865 /* always unregister in case we don't destroy any domains */
8866 unregister_sched_domain_sysctl();
8868 /* Let architecture update cpu core mappings. */
8869 new_topology = arch_update_cpu_topology();
8871 n = doms_new ? ndoms_new : 0;
8873 /* Destroy deleted domains */
8874 for (i = 0; i < ndoms_cur; i++) {
8875 for (j = 0; j < n && !new_topology; j++) {
8876 if (cpumask_equal(&doms_cur[i], &doms_new[j])
8877 && dattrs_equal(dattr_cur, i, dattr_new, j))
8880 /* no match - a current sched domain not in new doms_new[] */
8881 detach_destroy_domains(doms_cur + i);
8886 if (doms_new == NULL) {
8888 doms_new = fallback_doms;
8889 cpumask_andnot(&doms_new[0], cpu_online_mask, cpu_isolated_map);
8890 WARN_ON_ONCE(dattr_new);
8893 /* Build new domains */
8894 for (i = 0; i < ndoms_new; i++) {
8895 for (j = 0; j < ndoms_cur && !new_topology; j++) {
8896 if (cpumask_equal(&doms_new[i], &doms_cur[j])
8897 && dattrs_equal(dattr_new, i, dattr_cur, j))
8900 /* no match - add a new doms_new */
8901 __build_sched_domains(doms_new + i,
8902 dattr_new ? dattr_new + i : NULL);
8907 /* Remember the new sched domains */
8908 if (doms_cur != fallback_doms)
8910 kfree(dattr_cur); /* kfree(NULL) is safe */
8911 doms_cur = doms_new;
8912 dattr_cur = dattr_new;
8913 ndoms_cur = ndoms_new;
8915 register_sched_domain_sysctl();
8917 mutex_unlock(&sched_domains_mutex);
8920 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8921 static void arch_reinit_sched_domains(void)
8925 /* Destroy domains first to force the rebuild */
8926 partition_sched_domains(0, NULL, NULL);
8928 rebuild_sched_domains();
8932 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
8934 unsigned int level = 0;
8936 if (sscanf(buf, "%u", &level) != 1)
8940 * level is always be positive so don't check for
8941 * level < POWERSAVINGS_BALANCE_NONE which is 0
8942 * What happens on 0 or 1 byte write,
8943 * need to check for count as well?
8946 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
8950 sched_smt_power_savings = level;
8952 sched_mc_power_savings = level;
8954 arch_reinit_sched_domains();
8959 #ifdef CONFIG_SCHED_MC
8960 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
8963 return sprintf(page, "%u\n", sched_mc_power_savings);
8965 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
8966 const char *buf, size_t count)
8968 return sched_power_savings_store(buf, count, 0);
8970 static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
8971 sched_mc_power_savings_show,
8972 sched_mc_power_savings_store);
8975 #ifdef CONFIG_SCHED_SMT
8976 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
8979 return sprintf(page, "%u\n", sched_smt_power_savings);
8981 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
8982 const char *buf, size_t count)
8984 return sched_power_savings_store(buf, count, 1);
8986 static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
8987 sched_smt_power_savings_show,
8988 sched_smt_power_savings_store);
8991 int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
8995 #ifdef CONFIG_SCHED_SMT
8997 err = sysfs_create_file(&cls->kset.kobj,
8998 &attr_sched_smt_power_savings.attr);
9000 #ifdef CONFIG_SCHED_MC
9001 if (!err && mc_capable())
9002 err = sysfs_create_file(&cls->kset.kobj,
9003 &attr_sched_mc_power_savings.attr);
9007 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
9009 #ifndef CONFIG_CPUSETS
9011 * Add online and remove offline CPUs from the scheduler domains.
9012 * When cpusets are enabled they take over this function.
9014 static int update_sched_domains(struct notifier_block *nfb,
9015 unsigned long action, void *hcpu)
9019 case CPU_ONLINE_FROZEN:
9021 case CPU_DEAD_FROZEN:
9022 partition_sched_domains(1, NULL, NULL);
9031 static int update_runtime(struct notifier_block *nfb,
9032 unsigned long action, void *hcpu)
9034 int cpu = (int)(long)hcpu;
9037 case CPU_DOWN_PREPARE:
9038 case CPU_DOWN_PREPARE_FROZEN:
9039 disable_runtime(cpu_rq(cpu));
9042 case CPU_DOWN_FAILED:
9043 case CPU_DOWN_FAILED_FROZEN:
9045 case CPU_ONLINE_FROZEN:
9046 enable_runtime(cpu_rq(cpu));
9054 void __init sched_init_smp(void)
9056 cpumask_var_t non_isolated_cpus;
9058 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
9060 #if defined(CONFIG_NUMA)
9061 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
9063 BUG_ON(sched_group_nodes_bycpu == NULL);
9066 mutex_lock(&sched_domains_mutex);
9067 arch_init_sched_domains(cpu_online_mask);
9068 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
9069 if (cpumask_empty(non_isolated_cpus))
9070 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
9071 mutex_unlock(&sched_domains_mutex);
9074 #ifndef CONFIG_CPUSETS
9075 /* XXX: Theoretical race here - CPU may be hotplugged now */
9076 hotcpu_notifier(update_sched_domains, 0);
9079 /* RT runtime code needs to handle some hotplug events */
9080 hotcpu_notifier(update_runtime, 0);
9084 /* Move init over to a non-isolated CPU */
9085 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
9087 sched_init_granularity();
9088 free_cpumask_var(non_isolated_cpus);
9090 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
9091 init_sched_rt_class();
9094 void __init sched_init_smp(void)
9096 sched_init_granularity();
9098 #endif /* CONFIG_SMP */
9100 const_debug unsigned int sysctl_timer_migration = 1;
9102 int in_sched_functions(unsigned long addr)
9104 return in_lock_functions(addr) ||
9105 (addr >= (unsigned long)__sched_text_start
9106 && addr < (unsigned long)__sched_text_end);
9109 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
9111 cfs_rq->tasks_timeline = RB_ROOT;
9112 INIT_LIST_HEAD(&cfs_rq->tasks);
9113 #ifdef CONFIG_FAIR_GROUP_SCHED
9116 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
9119 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
9121 struct rt_prio_array *array;
9124 array = &rt_rq->active;
9125 for (i = 0; i < MAX_RT_PRIO; i++) {
9126 INIT_LIST_HEAD(array->queue + i);
9127 __clear_bit(i, array->bitmap);
9129 /* delimiter for bitsearch: */
9130 __set_bit(MAX_RT_PRIO, array->bitmap);
9132 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
9133 rt_rq->highest_prio.curr = MAX_RT_PRIO;
9135 rt_rq->highest_prio.next = MAX_RT_PRIO;
9139 rt_rq->rt_nr_migratory = 0;
9140 rt_rq->overloaded = 0;
9141 plist_head_init(&rt_rq->pushable_tasks, &rq->lock);
9145 rt_rq->rt_throttled = 0;
9146 rt_rq->rt_runtime = 0;
9147 spin_lock_init(&rt_rq->rt_runtime_lock);
9149 #ifdef CONFIG_RT_GROUP_SCHED
9150 rt_rq->rt_nr_boosted = 0;
9155 #ifdef CONFIG_FAIR_GROUP_SCHED
9156 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
9157 struct sched_entity *se, int cpu, int add,
9158 struct sched_entity *parent)
9160 struct rq *rq = cpu_rq(cpu);
9161 tg->cfs_rq[cpu] = cfs_rq;
9162 init_cfs_rq(cfs_rq, rq);
9165 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
9168 /* se could be NULL for init_task_group */
9173 se->cfs_rq = &rq->cfs;
9175 se->cfs_rq = parent->my_q;
9178 se->load.weight = tg->shares;
9179 se->load.inv_weight = 0;
9180 se->parent = parent;
9184 #ifdef CONFIG_RT_GROUP_SCHED
9185 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
9186 struct sched_rt_entity *rt_se, int cpu, int add,
9187 struct sched_rt_entity *parent)
9189 struct rq *rq = cpu_rq(cpu);
9191 tg->rt_rq[cpu] = rt_rq;
9192 init_rt_rq(rt_rq, rq);
9194 rt_rq->rt_se = rt_se;
9195 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
9197 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
9199 tg->rt_se[cpu] = rt_se;
9204 rt_se->rt_rq = &rq->rt;
9206 rt_se->rt_rq = parent->my_q;
9208 rt_se->my_q = rt_rq;
9209 rt_se->parent = parent;
9210 INIT_LIST_HEAD(&rt_se->run_list);
9214 void __init sched_init(void)
9217 unsigned long alloc_size = 0, ptr;
9219 #ifdef CONFIG_FAIR_GROUP_SCHED
9220 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
9222 #ifdef CONFIG_RT_GROUP_SCHED
9223 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
9225 #ifdef CONFIG_USER_SCHED
9228 #ifdef CONFIG_CPUMASK_OFFSTACK
9229 alloc_size += num_possible_cpus() * cpumask_size();
9232 * As sched_init() is called before page_alloc is setup,
9233 * we use alloc_bootmem().
9236 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
9238 #ifdef CONFIG_FAIR_GROUP_SCHED
9239 init_task_group.se = (struct sched_entity **)ptr;
9240 ptr += nr_cpu_ids * sizeof(void **);
9242 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
9243 ptr += nr_cpu_ids * sizeof(void **);
9245 #ifdef CONFIG_USER_SCHED
9246 root_task_group.se = (struct sched_entity **)ptr;
9247 ptr += nr_cpu_ids * sizeof(void **);
9249 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
9250 ptr += nr_cpu_ids * sizeof(void **);
9251 #endif /* CONFIG_USER_SCHED */
9252 #endif /* CONFIG_FAIR_GROUP_SCHED */
9253 #ifdef CONFIG_RT_GROUP_SCHED
9254 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
9255 ptr += nr_cpu_ids * sizeof(void **);
9257 init_task_group.rt_rq = (struct rt_rq **)ptr;
9258 ptr += nr_cpu_ids * sizeof(void **);
9260 #ifdef CONFIG_USER_SCHED
9261 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
9262 ptr += nr_cpu_ids * sizeof(void **);
9264 root_task_group.rt_rq = (struct rt_rq **)ptr;
9265 ptr += nr_cpu_ids * sizeof(void **);
9266 #endif /* CONFIG_USER_SCHED */
9267 #endif /* CONFIG_RT_GROUP_SCHED */
9268 #ifdef CONFIG_CPUMASK_OFFSTACK
9269 for_each_possible_cpu(i) {
9270 per_cpu(load_balance_tmpmask, i) = (void *)ptr;
9271 ptr += cpumask_size();
9273 #endif /* CONFIG_CPUMASK_OFFSTACK */
9277 init_defrootdomain();
9280 init_rt_bandwidth(&def_rt_bandwidth,
9281 global_rt_period(), global_rt_runtime());
9283 #ifdef CONFIG_RT_GROUP_SCHED
9284 init_rt_bandwidth(&init_task_group.rt_bandwidth,
9285 global_rt_period(), global_rt_runtime());
9286 #ifdef CONFIG_USER_SCHED
9287 init_rt_bandwidth(&root_task_group.rt_bandwidth,
9288 global_rt_period(), RUNTIME_INF);
9289 #endif /* CONFIG_USER_SCHED */
9290 #endif /* CONFIG_RT_GROUP_SCHED */
9292 #ifdef CONFIG_GROUP_SCHED
9293 list_add(&init_task_group.list, &task_groups);
9294 INIT_LIST_HEAD(&init_task_group.children);
9296 #ifdef CONFIG_USER_SCHED
9297 INIT_LIST_HEAD(&root_task_group.children);
9298 init_task_group.parent = &root_task_group;
9299 list_add(&init_task_group.siblings, &root_task_group.children);
9300 #endif /* CONFIG_USER_SCHED */
9301 #endif /* CONFIG_GROUP_SCHED */
9303 for_each_possible_cpu(i) {
9307 spin_lock_init(&rq->lock);
9309 rq->calc_load_active = 0;
9310 rq->calc_load_update = jiffies + LOAD_FREQ;
9311 init_cfs_rq(&rq->cfs, rq);
9312 init_rt_rq(&rq->rt, rq);
9313 #ifdef CONFIG_FAIR_GROUP_SCHED
9314 init_task_group.shares = init_task_group_load;
9315 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
9316 #ifdef CONFIG_CGROUP_SCHED
9318 * How much cpu bandwidth does init_task_group get?
9320 * In case of task-groups formed thr' the cgroup filesystem, it
9321 * gets 100% of the cpu resources in the system. This overall
9322 * system cpu resource is divided among the tasks of
9323 * init_task_group and its child task-groups in a fair manner,
9324 * based on each entity's (task or task-group's) weight
9325 * (se->load.weight).
9327 * In other words, if init_task_group has 10 tasks of weight
9328 * 1024) and two child groups A0 and A1 (of weight 1024 each),
9329 * then A0's share of the cpu resource is:
9331 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
9333 * We achieve this by letting init_task_group's tasks sit
9334 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
9336 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
9337 #elif defined CONFIG_USER_SCHED
9338 root_task_group.shares = NICE_0_LOAD;
9339 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
9341 * In case of task-groups formed thr' the user id of tasks,
9342 * init_task_group represents tasks belonging to root user.
9343 * Hence it forms a sibling of all subsequent groups formed.
9344 * In this case, init_task_group gets only a fraction of overall
9345 * system cpu resource, based on the weight assigned to root
9346 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
9347 * by letting tasks of init_task_group sit in a separate cfs_rq
9348 * (init_cfs_rq) and having one entity represent this group of
9349 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
9351 init_tg_cfs_entry(&init_task_group,
9352 &per_cpu(init_cfs_rq, i),
9353 &per_cpu(init_sched_entity, i), i, 1,
9354 root_task_group.se[i]);
9357 #endif /* CONFIG_FAIR_GROUP_SCHED */
9359 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
9360 #ifdef CONFIG_RT_GROUP_SCHED
9361 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
9362 #ifdef CONFIG_CGROUP_SCHED
9363 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
9364 #elif defined CONFIG_USER_SCHED
9365 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
9366 init_tg_rt_entry(&init_task_group,
9367 &per_cpu(init_rt_rq, i),
9368 &per_cpu(init_sched_rt_entity, i), i, 1,
9369 root_task_group.rt_se[i]);
9373 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
9374 rq->cpu_load[j] = 0;
9378 rq->active_balance = 0;
9379 rq->next_balance = jiffies;
9383 rq->migration_thread = NULL;
9384 INIT_LIST_HEAD(&rq->migration_queue);
9385 rq_attach_root(rq, &def_root_domain);
9388 atomic_set(&rq->nr_iowait, 0);
9391 set_load_weight(&init_task);
9393 #ifdef CONFIG_PREEMPT_NOTIFIERS
9394 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
9398 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
9401 #ifdef CONFIG_RT_MUTEXES
9402 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
9406 * The boot idle thread does lazy MMU switching as well:
9408 atomic_inc(&init_mm.mm_count);
9409 enter_lazy_tlb(&init_mm, current);
9412 * Make us the idle thread. Technically, schedule() should not be
9413 * called from this thread, however somewhere below it might be,
9414 * but because we are the idle thread, we just pick up running again
9415 * when this runqueue becomes "idle".
9417 init_idle(current, smp_processor_id());
9419 calc_load_update = jiffies + LOAD_FREQ;
9422 * During early bootup we pretend to be a normal task:
9424 current->sched_class = &fair_sched_class;
9426 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9427 alloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
9430 alloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
9431 alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
9433 alloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
9436 perf_counter_init();
9438 scheduler_running = 1;
9441 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9442 static inline int preempt_count_equals(int preempt_offset)
9444 int nested = preempt_count() & ~PREEMPT_ACTIVE;
9446 return (nested == PREEMPT_INATOMIC_BASE + preempt_offset);
9449 void __might_sleep(char *file, int line, int preempt_offset)
9452 static unsigned long prev_jiffy; /* ratelimiting */
9454 if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
9455 system_state != SYSTEM_RUNNING || oops_in_progress)
9457 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
9459 prev_jiffy = jiffies;
9462 "BUG: sleeping function called from invalid context at %s:%d\n",
9465 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9466 in_atomic(), irqs_disabled(),
9467 current->pid, current->comm);
9469 debug_show_held_locks(current);
9470 if (irqs_disabled())
9471 print_irqtrace_events(current);
9475 EXPORT_SYMBOL(__might_sleep);
9478 #ifdef CONFIG_MAGIC_SYSRQ
9479 static void normalize_task(struct rq *rq, struct task_struct *p)
9483 update_rq_clock(rq);
9484 on_rq = p->se.on_rq;
9486 deactivate_task(rq, p, 0);
9487 __setscheduler(rq, p, SCHED_NORMAL, 0);
9489 activate_task(rq, p, 0);
9490 resched_task(rq->curr);
9494 void normalize_rt_tasks(void)
9496 struct task_struct *g, *p;
9497 unsigned long flags;
9500 read_lock_irqsave(&tasklist_lock, flags);
9501 do_each_thread(g, p) {
9503 * Only normalize user tasks:
9508 p->se.exec_start = 0;
9509 #ifdef CONFIG_SCHEDSTATS
9510 p->se.wait_start = 0;
9511 p->se.sleep_start = 0;
9512 p->se.block_start = 0;
9517 * Renice negative nice level userspace
9520 if (TASK_NICE(p) < 0 && p->mm)
9521 set_user_nice(p, 0);
9525 spin_lock(&p->pi_lock);
9526 rq = __task_rq_lock(p);
9528 normalize_task(rq, p);
9530 __task_rq_unlock(rq);
9531 spin_unlock(&p->pi_lock);
9532 } while_each_thread(g, p);
9534 read_unlock_irqrestore(&tasklist_lock, flags);
9537 #endif /* CONFIG_MAGIC_SYSRQ */
9541 * These functions are only useful for the IA64 MCA handling.
9543 * They can only be called when the whole system has been
9544 * stopped - every CPU needs to be quiescent, and no scheduling
9545 * activity can take place. Using them for anything else would
9546 * be a serious bug, and as a result, they aren't even visible
9547 * under any other configuration.
9551 * curr_task - return the current task for a given cpu.
9552 * @cpu: the processor in question.
9554 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9556 struct task_struct *curr_task(int cpu)
9558 return cpu_curr(cpu);
9562 * set_curr_task - set the current task for a given cpu.
9563 * @cpu: the processor in question.
9564 * @p: the task pointer to set.
9566 * Description: This function must only be used when non-maskable interrupts
9567 * are serviced on a separate stack. It allows the architecture to switch the
9568 * notion of the current task on a cpu in a non-blocking manner. This function
9569 * must be called with all CPU's synchronized, and interrupts disabled, the
9570 * and caller must save the original value of the current task (see
9571 * curr_task() above) and restore that value before reenabling interrupts and
9572 * re-starting the system.
9574 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9576 void set_curr_task(int cpu, struct task_struct *p)
9583 #ifdef CONFIG_FAIR_GROUP_SCHED
9584 static void free_fair_sched_group(struct task_group *tg)
9588 for_each_possible_cpu(i) {
9590 kfree(tg->cfs_rq[i]);
9600 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
9602 struct cfs_rq *cfs_rq;
9603 struct sched_entity *se;
9607 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
9610 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
9614 tg->shares = NICE_0_LOAD;
9616 for_each_possible_cpu(i) {
9619 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
9620 GFP_KERNEL, cpu_to_node(i));
9624 se = kzalloc_node(sizeof(struct sched_entity),
9625 GFP_KERNEL, cpu_to_node(i));
9629 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
9638 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
9640 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
9641 &cpu_rq(cpu)->leaf_cfs_rq_list);
9644 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
9646 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
9648 #else /* !CONFG_FAIR_GROUP_SCHED */
9649 static inline void free_fair_sched_group(struct task_group *tg)
9654 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
9659 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
9663 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
9666 #endif /* CONFIG_FAIR_GROUP_SCHED */
9668 #ifdef CONFIG_RT_GROUP_SCHED
9669 static void free_rt_sched_group(struct task_group *tg)
9673 destroy_rt_bandwidth(&tg->rt_bandwidth);
9675 for_each_possible_cpu(i) {
9677 kfree(tg->rt_rq[i]);
9679 kfree(tg->rt_se[i]);
9687 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
9689 struct rt_rq *rt_rq;
9690 struct sched_rt_entity *rt_se;
9694 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
9697 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
9701 init_rt_bandwidth(&tg->rt_bandwidth,
9702 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
9704 for_each_possible_cpu(i) {
9707 rt_rq = kzalloc_node(sizeof(struct rt_rq),
9708 GFP_KERNEL, cpu_to_node(i));
9712 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
9713 GFP_KERNEL, cpu_to_node(i));
9717 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
9726 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
9728 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
9729 &cpu_rq(cpu)->leaf_rt_rq_list);
9732 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
9734 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
9736 #else /* !CONFIG_RT_GROUP_SCHED */
9737 static inline void free_rt_sched_group(struct task_group *tg)
9742 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
9747 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
9751 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
9754 #endif /* CONFIG_RT_GROUP_SCHED */
9756 #ifdef CONFIG_GROUP_SCHED
9757 static void free_sched_group(struct task_group *tg)
9759 free_fair_sched_group(tg);
9760 free_rt_sched_group(tg);
9764 /* allocate runqueue etc for a new task group */
9765 struct task_group *sched_create_group(struct task_group *parent)
9767 struct task_group *tg;
9768 unsigned long flags;
9771 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
9773 return ERR_PTR(-ENOMEM);
9775 if (!alloc_fair_sched_group(tg, parent))
9778 if (!alloc_rt_sched_group(tg, parent))
9781 spin_lock_irqsave(&task_group_lock, flags);
9782 for_each_possible_cpu(i) {
9783 register_fair_sched_group(tg, i);
9784 register_rt_sched_group(tg, i);
9786 list_add_rcu(&tg->list, &task_groups);
9788 WARN_ON(!parent); /* root should already exist */
9790 tg->parent = parent;
9791 INIT_LIST_HEAD(&tg->children);
9792 list_add_rcu(&tg->siblings, &parent->children);
9793 spin_unlock_irqrestore(&task_group_lock, flags);
9798 free_sched_group(tg);
9799 return ERR_PTR(-ENOMEM);
9802 /* rcu callback to free various structures associated with a task group */
9803 static void free_sched_group_rcu(struct rcu_head *rhp)
9805 /* now it should be safe to free those cfs_rqs */
9806 free_sched_group(container_of(rhp, struct task_group, rcu));
9809 /* Destroy runqueue etc associated with a task group */
9810 void sched_destroy_group(struct task_group *tg)
9812 unsigned long flags;
9815 spin_lock_irqsave(&task_group_lock, flags);
9816 for_each_possible_cpu(i) {
9817 unregister_fair_sched_group(tg, i);
9818 unregister_rt_sched_group(tg, i);
9820 list_del_rcu(&tg->list);
9821 list_del_rcu(&tg->siblings);
9822 spin_unlock_irqrestore(&task_group_lock, flags);
9824 /* wait for possible concurrent references to cfs_rqs complete */
9825 call_rcu(&tg->rcu, free_sched_group_rcu);
9828 /* change task's runqueue when it moves between groups.
9829 * The caller of this function should have put the task in its new group
9830 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
9831 * reflect its new group.
9833 void sched_move_task(struct task_struct *tsk)
9836 unsigned long flags;
9839 rq = task_rq_lock(tsk, &flags);
9841 update_rq_clock(rq);
9843 running = task_current(rq, tsk);
9844 on_rq = tsk->se.on_rq;
9847 dequeue_task(rq, tsk, 0);
9848 if (unlikely(running))
9849 tsk->sched_class->put_prev_task(rq, tsk);
9851 set_task_rq(tsk, task_cpu(tsk));
9853 #ifdef CONFIG_FAIR_GROUP_SCHED
9854 if (tsk->sched_class->moved_group)
9855 tsk->sched_class->moved_group(tsk);
9858 if (unlikely(running))
9859 tsk->sched_class->set_curr_task(rq);
9861 enqueue_task(rq, tsk, 0);
9863 task_rq_unlock(rq, &flags);
9865 #endif /* CONFIG_GROUP_SCHED */
9867 #ifdef CONFIG_FAIR_GROUP_SCHED
9868 static void __set_se_shares(struct sched_entity *se, unsigned long shares)
9870 struct cfs_rq *cfs_rq = se->cfs_rq;
9875 dequeue_entity(cfs_rq, se, 0);
9877 se->load.weight = shares;
9878 se->load.inv_weight = 0;
9881 enqueue_entity(cfs_rq, se, 0);
9884 static void set_se_shares(struct sched_entity *se, unsigned long shares)
9886 struct cfs_rq *cfs_rq = se->cfs_rq;
9887 struct rq *rq = cfs_rq->rq;
9888 unsigned long flags;
9890 spin_lock_irqsave(&rq->lock, flags);
9891 __set_se_shares(se, shares);
9892 spin_unlock_irqrestore(&rq->lock, flags);
9895 static DEFINE_MUTEX(shares_mutex);
9897 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
9900 unsigned long flags;
9903 * We can't change the weight of the root cgroup.
9908 if (shares < MIN_SHARES)
9909 shares = MIN_SHARES;
9910 else if (shares > MAX_SHARES)
9911 shares = MAX_SHARES;
9913 mutex_lock(&shares_mutex);
9914 if (tg->shares == shares)
9917 spin_lock_irqsave(&task_group_lock, flags);
9918 for_each_possible_cpu(i)
9919 unregister_fair_sched_group(tg, i);
9920 list_del_rcu(&tg->siblings);
9921 spin_unlock_irqrestore(&task_group_lock, flags);
9923 /* wait for any ongoing reference to this group to finish */
9924 synchronize_sched();
9927 * Now we are free to modify the group's share on each cpu
9928 * w/o tripping rebalance_share or load_balance_fair.
9930 tg->shares = shares;
9931 for_each_possible_cpu(i) {
9935 cfs_rq_set_shares(tg->cfs_rq[i], 0);
9936 set_se_shares(tg->se[i], shares);
9940 * Enable load balance activity on this group, by inserting it back on
9941 * each cpu's rq->leaf_cfs_rq_list.
9943 spin_lock_irqsave(&task_group_lock, flags);
9944 for_each_possible_cpu(i)
9945 register_fair_sched_group(tg, i);
9946 list_add_rcu(&tg->siblings, &tg->parent->children);
9947 spin_unlock_irqrestore(&task_group_lock, flags);
9949 mutex_unlock(&shares_mutex);
9953 unsigned long sched_group_shares(struct task_group *tg)
9959 #ifdef CONFIG_RT_GROUP_SCHED
9961 * Ensure that the real time constraints are schedulable.
9963 static DEFINE_MUTEX(rt_constraints_mutex);
9965 static unsigned long to_ratio(u64 period, u64 runtime)
9967 if (runtime == RUNTIME_INF)
9970 return div64_u64(runtime << 20, period);
9973 /* Must be called with tasklist_lock held */
9974 static inline int tg_has_rt_tasks(struct task_group *tg)
9976 struct task_struct *g, *p;
9978 do_each_thread(g, p) {
9979 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
9981 } while_each_thread(g, p);
9986 struct rt_schedulable_data {
9987 struct task_group *tg;
9992 static int tg_schedulable(struct task_group *tg, void *data)
9994 struct rt_schedulable_data *d = data;
9995 struct task_group *child;
9996 unsigned long total, sum = 0;
9997 u64 period, runtime;
9999 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
10000 runtime = tg->rt_bandwidth.rt_runtime;
10003 period = d->rt_period;
10004 runtime = d->rt_runtime;
10007 #ifdef CONFIG_USER_SCHED
10008 if (tg == &root_task_group) {
10009 period = global_rt_period();
10010 runtime = global_rt_runtime();
10015 * Cannot have more runtime than the period.
10017 if (runtime > period && runtime != RUNTIME_INF)
10021 * Ensure we don't starve existing RT tasks.
10023 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
10026 total = to_ratio(period, runtime);
10029 * Nobody can have more than the global setting allows.
10031 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
10035 * The sum of our children's runtime should not exceed our own.
10037 list_for_each_entry_rcu(child, &tg->children, siblings) {
10038 period = ktime_to_ns(child->rt_bandwidth.rt_period);
10039 runtime = child->rt_bandwidth.rt_runtime;
10041 if (child == d->tg) {
10042 period = d->rt_period;
10043 runtime = d->rt_runtime;
10046 sum += to_ratio(period, runtime);
10055 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
10057 struct rt_schedulable_data data = {
10059 .rt_period = period,
10060 .rt_runtime = runtime,
10063 return walk_tg_tree(tg_schedulable, tg_nop, &data);
10066 static int tg_set_bandwidth(struct task_group *tg,
10067 u64 rt_period, u64 rt_runtime)
10071 mutex_lock(&rt_constraints_mutex);
10072 read_lock(&tasklist_lock);
10073 err = __rt_schedulable(tg, rt_period, rt_runtime);
10077 spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
10078 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
10079 tg->rt_bandwidth.rt_runtime = rt_runtime;
10081 for_each_possible_cpu(i) {
10082 struct rt_rq *rt_rq = tg->rt_rq[i];
10084 spin_lock(&rt_rq->rt_runtime_lock);
10085 rt_rq->rt_runtime = rt_runtime;
10086 spin_unlock(&rt_rq->rt_runtime_lock);
10088 spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
10090 read_unlock(&tasklist_lock);
10091 mutex_unlock(&rt_constraints_mutex);
10096 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
10098 u64 rt_runtime, rt_period;
10100 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
10101 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
10102 if (rt_runtime_us < 0)
10103 rt_runtime = RUNTIME_INF;
10105 return tg_set_bandwidth(tg, rt_period, rt_runtime);
10108 long sched_group_rt_runtime(struct task_group *tg)
10112 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
10115 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
10116 do_div(rt_runtime_us, NSEC_PER_USEC);
10117 return rt_runtime_us;
10120 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
10122 u64 rt_runtime, rt_period;
10124 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
10125 rt_runtime = tg->rt_bandwidth.rt_runtime;
10127 if (rt_period == 0)
10130 return tg_set_bandwidth(tg, rt_period, rt_runtime);
10133 long sched_group_rt_period(struct task_group *tg)
10137 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
10138 do_div(rt_period_us, NSEC_PER_USEC);
10139 return rt_period_us;
10142 static int sched_rt_global_constraints(void)
10144 u64 runtime, period;
10147 if (sysctl_sched_rt_period <= 0)
10150 runtime = global_rt_runtime();
10151 period = global_rt_period();
10154 * Sanity check on the sysctl variables.
10156 if (runtime > period && runtime != RUNTIME_INF)
10159 mutex_lock(&rt_constraints_mutex);
10160 read_lock(&tasklist_lock);
10161 ret = __rt_schedulable(NULL, 0, 0);
10162 read_unlock(&tasklist_lock);
10163 mutex_unlock(&rt_constraints_mutex);
10168 int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
10170 /* Don't accept realtime tasks when there is no way for them to run */
10171 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
10177 #else /* !CONFIG_RT_GROUP_SCHED */
10178 static int sched_rt_global_constraints(void)
10180 unsigned long flags;
10183 if (sysctl_sched_rt_period <= 0)
10187 * There's always some RT tasks in the root group
10188 * -- migration, kstopmachine etc..
10190 if (sysctl_sched_rt_runtime == 0)
10193 spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
10194 for_each_possible_cpu(i) {
10195 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
10197 spin_lock(&rt_rq->rt_runtime_lock);
10198 rt_rq->rt_runtime = global_rt_runtime();
10199 spin_unlock(&rt_rq->rt_runtime_lock);
10201 spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
10205 #endif /* CONFIG_RT_GROUP_SCHED */
10207 int sched_rt_handler(struct ctl_table *table, int write,
10208 struct file *filp, void __user *buffer, size_t *lenp,
10212 int old_period, old_runtime;
10213 static DEFINE_MUTEX(mutex);
10215 mutex_lock(&mutex);
10216 old_period = sysctl_sched_rt_period;
10217 old_runtime = sysctl_sched_rt_runtime;
10219 ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
10221 if (!ret && write) {
10222 ret = sched_rt_global_constraints();
10224 sysctl_sched_rt_period = old_period;
10225 sysctl_sched_rt_runtime = old_runtime;
10227 def_rt_bandwidth.rt_runtime = global_rt_runtime();
10228 def_rt_bandwidth.rt_period =
10229 ns_to_ktime(global_rt_period());
10232 mutex_unlock(&mutex);
10237 #ifdef CONFIG_CGROUP_SCHED
10239 /* return corresponding task_group object of a cgroup */
10240 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
10242 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
10243 struct task_group, css);
10246 static struct cgroup_subsys_state *
10247 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
10249 struct task_group *tg, *parent;
10251 if (!cgrp->parent) {
10252 /* This is early initialization for the top cgroup */
10253 return &init_task_group.css;
10256 parent = cgroup_tg(cgrp->parent);
10257 tg = sched_create_group(parent);
10259 return ERR_PTR(-ENOMEM);
10265 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
10267 struct task_group *tg = cgroup_tg(cgrp);
10269 sched_destroy_group(tg);
10273 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
10274 struct task_struct *tsk)
10276 #ifdef CONFIG_RT_GROUP_SCHED
10277 if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
10280 /* We don't support RT-tasks being in separate groups */
10281 if (tsk->sched_class != &fair_sched_class)
10289 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
10290 struct cgroup *old_cont, struct task_struct *tsk)
10292 sched_move_task(tsk);
10295 #ifdef CONFIG_FAIR_GROUP_SCHED
10296 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
10299 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
10302 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
10304 struct task_group *tg = cgroup_tg(cgrp);
10306 return (u64) tg->shares;
10308 #endif /* CONFIG_FAIR_GROUP_SCHED */
10310 #ifdef CONFIG_RT_GROUP_SCHED
10311 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
10314 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
10317 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
10319 return sched_group_rt_runtime(cgroup_tg(cgrp));
10322 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
10325 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
10328 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
10330 return sched_group_rt_period(cgroup_tg(cgrp));
10332 #endif /* CONFIG_RT_GROUP_SCHED */
10334 static struct cftype cpu_files[] = {
10335 #ifdef CONFIG_FAIR_GROUP_SCHED
10338 .read_u64 = cpu_shares_read_u64,
10339 .write_u64 = cpu_shares_write_u64,
10342 #ifdef CONFIG_RT_GROUP_SCHED
10344 .name = "rt_runtime_us",
10345 .read_s64 = cpu_rt_runtime_read,
10346 .write_s64 = cpu_rt_runtime_write,
10349 .name = "rt_period_us",
10350 .read_u64 = cpu_rt_period_read_uint,
10351 .write_u64 = cpu_rt_period_write_uint,
10356 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
10358 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
10361 struct cgroup_subsys cpu_cgroup_subsys = {
10363 .create = cpu_cgroup_create,
10364 .destroy = cpu_cgroup_destroy,
10365 .can_attach = cpu_cgroup_can_attach,
10366 .attach = cpu_cgroup_attach,
10367 .populate = cpu_cgroup_populate,
10368 .subsys_id = cpu_cgroup_subsys_id,
10372 #endif /* CONFIG_CGROUP_SCHED */
10374 #ifdef CONFIG_CGROUP_CPUACCT
10377 * CPU accounting code for task groups.
10379 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
10380 * (balbir@in.ibm.com).
10383 /* track cpu usage of a group of tasks and its child groups */
10385 struct cgroup_subsys_state css;
10386 /* cpuusage holds pointer to a u64-type object on every cpu */
10388 struct percpu_counter cpustat[CPUACCT_STAT_NSTATS];
10389 struct cpuacct *parent;
10392 struct cgroup_subsys cpuacct_subsys;
10394 /* return cpu accounting group corresponding to this container */
10395 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
10397 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
10398 struct cpuacct, css);
10401 /* return cpu accounting group to which this task belongs */
10402 static inline struct cpuacct *task_ca(struct task_struct *tsk)
10404 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
10405 struct cpuacct, css);
10408 /* create a new cpu accounting group */
10409 static struct cgroup_subsys_state *cpuacct_create(
10410 struct cgroup_subsys *ss, struct cgroup *cgrp)
10412 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
10418 ca->cpuusage = alloc_percpu(u64);
10422 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
10423 if (percpu_counter_init(&ca->cpustat[i], 0))
10424 goto out_free_counters;
10427 ca->parent = cgroup_ca(cgrp->parent);
10433 percpu_counter_destroy(&ca->cpustat[i]);
10434 free_percpu(ca->cpuusage);
10438 return ERR_PTR(-ENOMEM);
10441 /* destroy an existing cpu accounting group */
10443 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
10445 struct cpuacct *ca = cgroup_ca(cgrp);
10448 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
10449 percpu_counter_destroy(&ca->cpustat[i]);
10450 free_percpu(ca->cpuusage);
10454 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
10456 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10459 #ifndef CONFIG_64BIT
10461 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10463 spin_lock_irq(&cpu_rq(cpu)->lock);
10465 spin_unlock_irq(&cpu_rq(cpu)->lock);
10473 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
10475 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10477 #ifndef CONFIG_64BIT
10479 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10481 spin_lock_irq(&cpu_rq(cpu)->lock);
10483 spin_unlock_irq(&cpu_rq(cpu)->lock);
10489 /* return total cpu usage (in nanoseconds) of a group */
10490 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
10492 struct cpuacct *ca = cgroup_ca(cgrp);
10493 u64 totalcpuusage = 0;
10496 for_each_present_cpu(i)
10497 totalcpuusage += cpuacct_cpuusage_read(ca, i);
10499 return totalcpuusage;
10502 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
10505 struct cpuacct *ca = cgroup_ca(cgrp);
10514 for_each_present_cpu(i)
10515 cpuacct_cpuusage_write(ca, i, 0);
10521 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
10522 struct seq_file *m)
10524 struct cpuacct *ca = cgroup_ca(cgroup);
10528 for_each_present_cpu(i) {
10529 percpu = cpuacct_cpuusage_read(ca, i);
10530 seq_printf(m, "%llu ", (unsigned long long) percpu);
10532 seq_printf(m, "\n");
10536 static const char *cpuacct_stat_desc[] = {
10537 [CPUACCT_STAT_USER] = "user",
10538 [CPUACCT_STAT_SYSTEM] = "system",
10541 static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
10542 struct cgroup_map_cb *cb)
10544 struct cpuacct *ca = cgroup_ca(cgrp);
10547 for (i = 0; i < CPUACCT_STAT_NSTATS; i++) {
10548 s64 val = percpu_counter_read(&ca->cpustat[i]);
10549 val = cputime64_to_clock_t(val);
10550 cb->fill(cb, cpuacct_stat_desc[i], val);
10555 static struct cftype files[] = {
10558 .read_u64 = cpuusage_read,
10559 .write_u64 = cpuusage_write,
10562 .name = "usage_percpu",
10563 .read_seq_string = cpuacct_percpu_seq_read,
10567 .read_map = cpuacct_stats_show,
10571 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
10573 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
10577 * charge this task's execution time to its accounting group.
10579 * called with rq->lock held.
10581 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
10583 struct cpuacct *ca;
10586 if (unlikely(!cpuacct_subsys.active))
10589 cpu = task_cpu(tsk);
10595 for (; ca; ca = ca->parent) {
10596 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10597 *cpuusage += cputime;
10604 * Charge the system/user time to the task's accounting group.
10606 static void cpuacct_update_stats(struct task_struct *tsk,
10607 enum cpuacct_stat_index idx, cputime_t val)
10609 struct cpuacct *ca;
10611 if (unlikely(!cpuacct_subsys.active))
10618 percpu_counter_add(&ca->cpustat[idx], val);
10624 struct cgroup_subsys cpuacct_subsys = {
10626 .create = cpuacct_create,
10627 .destroy = cpuacct_destroy,
10628 .populate = cpuacct_populate,
10629 .subsys_id = cpuacct_subsys_id,
10631 #endif /* CONFIG_CGROUP_CPUACCT */