4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/kthread.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/reciprocal_div.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/bootmem.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
75 #include <trace/sched.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
83 * Convert user-nice values [ -20 ... 0 ... 19 ]
84 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
87 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
88 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
89 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
92 * 'User priority' is the nice value converted to something we
93 * can work with better when scaling various scheduler parameters,
94 * it's a [ 0 ... 39 ] range.
96 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
97 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
98 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
101 * Helpers for converting nanosecond timing to jiffy resolution
103 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
105 #define NICE_0_LOAD SCHED_LOAD_SCALE
106 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
109 * These are the 'tuning knobs' of the scheduler:
111 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
112 * Timeslices get refilled after they expire.
114 #define DEF_TIMESLICE (100 * HZ / 1000)
117 * single value that denotes runtime == period, ie unlimited time.
119 #define RUNTIME_INF ((u64)~0ULL)
121 DEFINE_TRACE(sched_wait_task);
122 DEFINE_TRACE(sched_wakeup);
123 DEFINE_TRACE(sched_wakeup_new);
124 DEFINE_TRACE(sched_switch);
125 DEFINE_TRACE(sched_migrate_task);
129 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
130 * Since cpu_power is a 'constant', we can use a reciprocal divide.
132 static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
134 return reciprocal_divide(load, sg->reciprocal_cpu_power);
138 * Each time a sched group cpu_power is changed,
139 * we must compute its reciprocal value
141 static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
143 sg->__cpu_power += val;
144 sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
148 static inline int rt_policy(int policy)
150 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
155 static inline int task_has_rt_policy(struct task_struct *p)
157 return rt_policy(p->policy);
161 * This is the priority-queue data structure of the RT scheduling class:
163 struct rt_prio_array {
164 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
165 struct list_head queue[MAX_RT_PRIO];
168 struct rt_bandwidth {
169 /* nests inside the rq lock: */
170 spinlock_t rt_runtime_lock;
173 struct hrtimer rt_period_timer;
176 static struct rt_bandwidth def_rt_bandwidth;
178 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
180 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
182 struct rt_bandwidth *rt_b =
183 container_of(timer, struct rt_bandwidth, rt_period_timer);
189 now = hrtimer_cb_get_time(timer);
190 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
195 idle = do_sched_rt_period_timer(rt_b, overrun);
198 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
202 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
204 rt_b->rt_period = ns_to_ktime(period);
205 rt_b->rt_runtime = runtime;
207 spin_lock_init(&rt_b->rt_runtime_lock);
209 hrtimer_init(&rt_b->rt_period_timer,
210 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
211 rt_b->rt_period_timer.function = sched_rt_period_timer;
212 rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED;
215 static inline int rt_bandwidth_enabled(void)
217 return sysctl_sched_rt_runtime >= 0;
220 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
224 if (rt_bandwidth_enabled() && rt_b->rt_runtime == RUNTIME_INF)
227 if (hrtimer_active(&rt_b->rt_period_timer))
230 spin_lock(&rt_b->rt_runtime_lock);
232 if (hrtimer_active(&rt_b->rt_period_timer))
235 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
236 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
237 hrtimer_start_expires(&rt_b->rt_period_timer,
240 spin_unlock(&rt_b->rt_runtime_lock);
243 #ifdef CONFIG_RT_GROUP_SCHED
244 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
246 hrtimer_cancel(&rt_b->rt_period_timer);
251 * sched_domains_mutex serializes calls to arch_init_sched_domains,
252 * detach_destroy_domains and partition_sched_domains.
254 static DEFINE_MUTEX(sched_domains_mutex);
256 #ifdef CONFIG_GROUP_SCHED
258 #include <linux/cgroup.h>
262 static LIST_HEAD(task_groups);
264 /* task group related information */
266 #ifdef CONFIG_CGROUP_SCHED
267 struct cgroup_subsys_state css;
270 #ifdef CONFIG_FAIR_GROUP_SCHED
271 /* schedulable entities of this group on each cpu */
272 struct sched_entity **se;
273 /* runqueue "owned" by this group on each cpu */
274 struct cfs_rq **cfs_rq;
275 unsigned long shares;
278 #ifdef CONFIG_RT_GROUP_SCHED
279 struct sched_rt_entity **rt_se;
280 struct rt_rq **rt_rq;
282 struct rt_bandwidth rt_bandwidth;
286 struct list_head list;
288 struct task_group *parent;
289 struct list_head siblings;
290 struct list_head children;
293 #ifdef CONFIG_USER_SCHED
297 * Every UID task group (including init_task_group aka UID-0) will
298 * be a child to this group.
300 struct task_group root_task_group;
302 #ifdef CONFIG_FAIR_GROUP_SCHED
303 /* Default task group's sched entity on each cpu */
304 static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
305 /* Default task group's cfs_rq on each cpu */
306 static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
307 #endif /* CONFIG_FAIR_GROUP_SCHED */
309 #ifdef CONFIG_RT_GROUP_SCHED
310 static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
311 static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
312 #endif /* CONFIG_RT_GROUP_SCHED */
313 #else /* !CONFIG_USER_SCHED */
314 #define root_task_group init_task_group
315 #endif /* CONFIG_USER_SCHED */
317 /* task_group_lock serializes add/remove of task groups and also changes to
318 * a task group's cpu shares.
320 static DEFINE_SPINLOCK(task_group_lock);
322 #ifdef CONFIG_FAIR_GROUP_SCHED
323 #ifdef CONFIG_USER_SCHED
324 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
325 #else /* !CONFIG_USER_SCHED */
326 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
327 #endif /* CONFIG_USER_SCHED */
330 * A weight of 0 or 1 can cause arithmetics problems.
331 * A weight of a cfs_rq is the sum of weights of which entities
332 * are queued on this cfs_rq, so a weight of a entity should not be
333 * too large, so as the shares value of a task group.
334 * (The default weight is 1024 - so there's no practical
335 * limitation from this.)
338 #define MAX_SHARES (1UL << 18)
340 static int init_task_group_load = INIT_TASK_GROUP_LOAD;
343 /* Default task group.
344 * Every task in system belong to this group at bootup.
346 struct task_group init_task_group;
348 /* return group to which a task belongs */
349 static inline struct task_group *task_group(struct task_struct *p)
351 struct task_group *tg;
353 #ifdef CONFIG_USER_SCHED
355 #elif defined(CONFIG_CGROUP_SCHED)
356 tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
357 struct task_group, css);
359 tg = &init_task_group;
364 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
365 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
367 #ifdef CONFIG_FAIR_GROUP_SCHED
368 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
369 p->se.parent = task_group(p)->se[cpu];
372 #ifdef CONFIG_RT_GROUP_SCHED
373 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
374 p->rt.parent = task_group(p)->rt_se[cpu];
380 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
381 static inline struct task_group *task_group(struct task_struct *p)
386 #endif /* CONFIG_GROUP_SCHED */
388 /* CFS-related fields in a runqueue */
390 struct load_weight load;
391 unsigned long nr_running;
396 struct rb_root tasks_timeline;
397 struct rb_node *rb_leftmost;
399 struct list_head tasks;
400 struct list_head *balance_iterator;
403 * 'curr' points to currently running entity on this cfs_rq.
404 * It is set to NULL otherwise (i.e when none are currently running).
406 struct sched_entity *curr, *next, *last;
408 unsigned int nr_spread_over;
410 #ifdef CONFIG_FAIR_GROUP_SCHED
411 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
414 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
415 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
416 * (like users, containers etc.)
418 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
419 * list is used during load balance.
421 struct list_head leaf_cfs_rq_list;
422 struct task_group *tg; /* group that "owns" this runqueue */
426 * the part of load.weight contributed by tasks
428 unsigned long task_weight;
431 * h_load = weight * f(tg)
433 * Where f(tg) is the recursive weight fraction assigned to
436 unsigned long h_load;
439 * this cpu's part of tg->shares
441 unsigned long shares;
444 * load.weight at the time we set shares
446 unsigned long rq_weight;
451 /* Real-Time classes' related field in a runqueue: */
453 struct rt_prio_array active;
454 unsigned long rt_nr_running;
455 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
456 int highest_prio; /* highest queued rt task prio */
459 unsigned long rt_nr_migratory;
465 /* Nests inside the rq lock: */
466 spinlock_t rt_runtime_lock;
468 #ifdef CONFIG_RT_GROUP_SCHED
469 unsigned long rt_nr_boosted;
472 struct list_head leaf_rt_rq_list;
473 struct task_group *tg;
474 struct sched_rt_entity *rt_se;
481 * We add the notion of a root-domain which will be used to define per-domain
482 * variables. Each exclusive cpuset essentially defines an island domain by
483 * fully partitioning the member cpus from any other cpuset. Whenever a new
484 * exclusive cpuset is created, we also create and attach a new root-domain
494 * The "RT overload" flag: it gets set if a CPU has more than
495 * one runnable RT task.
500 struct cpupri cpupri;
505 * By default the system creates a single root-domain with all cpus as
506 * members (mimicking the global state we have today).
508 static struct root_domain def_root_domain;
513 * This is the main, per-CPU runqueue data structure.
515 * Locking rule: those places that want to lock multiple runqueues
516 * (such as the load balancing or the thread migration code), lock
517 * acquire operations must be ordered by ascending &runqueue.
524 * nr_running and cpu_load should be in the same cacheline because
525 * remote CPUs use both these fields when doing load calculation.
527 unsigned long nr_running;
528 #define CPU_LOAD_IDX_MAX 5
529 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
530 unsigned char idle_at_tick;
532 unsigned long last_tick_seen;
533 unsigned char in_nohz_recently;
535 /* capture load from *all* tasks on this cpu: */
536 struct load_weight load;
537 unsigned long nr_load_updates;
543 #ifdef CONFIG_FAIR_GROUP_SCHED
544 /* list of leaf cfs_rq on this cpu: */
545 struct list_head leaf_cfs_rq_list;
547 #ifdef CONFIG_RT_GROUP_SCHED
548 struct list_head leaf_rt_rq_list;
552 * This is part of a global counter where only the total sum
553 * over all CPUs matters. A task can increase this counter on
554 * one CPU and if it got migrated afterwards it may decrease
555 * it on another CPU. Always updated under the runqueue lock:
557 unsigned long nr_uninterruptible;
559 struct task_struct *curr, *idle;
560 unsigned long next_balance;
561 struct mm_struct *prev_mm;
568 struct root_domain *rd;
569 struct sched_domain *sd;
571 /* For active balancing */
574 /* cpu of this runqueue: */
578 unsigned long avg_load_per_task;
580 struct task_struct *migration_thread;
581 struct list_head migration_queue;
584 #ifdef CONFIG_SCHED_HRTICK
586 int hrtick_csd_pending;
587 struct call_single_data hrtick_csd;
589 struct hrtimer hrtick_timer;
592 #ifdef CONFIG_SCHEDSTATS
594 struct sched_info rq_sched_info;
596 /* sys_sched_yield() stats */
597 unsigned int yld_exp_empty;
598 unsigned int yld_act_empty;
599 unsigned int yld_both_empty;
600 unsigned int yld_count;
602 /* schedule() stats */
603 unsigned int sched_switch;
604 unsigned int sched_count;
605 unsigned int sched_goidle;
607 /* try_to_wake_up() stats */
608 unsigned int ttwu_count;
609 unsigned int ttwu_local;
612 unsigned int bkl_count;
616 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
618 static inline void check_preempt_curr(struct rq *rq, struct task_struct *p, int sync)
620 rq->curr->sched_class->check_preempt_curr(rq, p, sync);
623 static inline int cpu_of(struct rq *rq)
633 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
634 * See detach_destroy_domains: synchronize_sched for details.
636 * The domain tree of any CPU may only be accessed from within
637 * preempt-disabled sections.
639 #define for_each_domain(cpu, __sd) \
640 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
642 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
643 #define this_rq() (&__get_cpu_var(runqueues))
644 #define task_rq(p) cpu_rq(task_cpu(p))
645 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
647 static inline void update_rq_clock(struct rq *rq)
649 rq->clock = sched_clock_cpu(cpu_of(rq));
653 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
655 #ifdef CONFIG_SCHED_DEBUG
656 # define const_debug __read_mostly
658 # define const_debug static const
664 * Returns true if the current cpu runqueue is locked.
665 * This interface allows printk to be called with the runqueue lock
666 * held and know whether or not it is OK to wake up the klogd.
668 int runqueue_is_locked(void)
671 struct rq *rq = cpu_rq(cpu);
674 ret = spin_is_locked(&rq->lock);
680 * Debugging: various feature bits
683 #define SCHED_FEAT(name, enabled) \
684 __SCHED_FEAT_##name ,
687 #include "sched_features.h"
692 #define SCHED_FEAT(name, enabled) \
693 (1UL << __SCHED_FEAT_##name) * enabled |
695 const_debug unsigned int sysctl_sched_features =
696 #include "sched_features.h"
701 #ifdef CONFIG_SCHED_DEBUG
702 #define SCHED_FEAT(name, enabled) \
705 static __read_mostly char *sched_feat_names[] = {
706 #include "sched_features.h"
712 static int sched_feat_show(struct seq_file *m, void *v)
716 for (i = 0; sched_feat_names[i]; i++) {
717 if (!(sysctl_sched_features & (1UL << i)))
719 seq_printf(m, "%s ", sched_feat_names[i]);
727 sched_feat_write(struct file *filp, const char __user *ubuf,
728 size_t cnt, loff_t *ppos)
738 if (copy_from_user(&buf, ubuf, cnt))
743 if (strncmp(buf, "NO_", 3) == 0) {
748 for (i = 0; sched_feat_names[i]; i++) {
749 int len = strlen(sched_feat_names[i]);
751 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
753 sysctl_sched_features &= ~(1UL << i);
755 sysctl_sched_features |= (1UL << i);
760 if (!sched_feat_names[i])
768 static int sched_feat_open(struct inode *inode, struct file *filp)
770 return single_open(filp, sched_feat_show, NULL);
773 static struct file_operations sched_feat_fops = {
774 .open = sched_feat_open,
775 .write = sched_feat_write,
778 .release = single_release,
781 static __init int sched_init_debug(void)
783 debugfs_create_file("sched_features", 0644, NULL, NULL,
788 late_initcall(sched_init_debug);
792 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
795 * Number of tasks to iterate in a single balance run.
796 * Limited because this is done with IRQs disabled.
798 const_debug unsigned int sysctl_sched_nr_migrate = 32;
801 * ratelimit for updating the group shares.
804 unsigned int sysctl_sched_shares_ratelimit = 250000;
807 * Inject some fuzzyness into changing the per-cpu group shares
808 * this avoids remote rq-locks at the expense of fairness.
811 unsigned int sysctl_sched_shares_thresh = 4;
814 * period over which we measure -rt task cpu usage in us.
817 unsigned int sysctl_sched_rt_period = 1000000;
819 static __read_mostly int scheduler_running;
822 * part of the period that we allow rt tasks to run in us.
825 int sysctl_sched_rt_runtime = 950000;
827 static inline u64 global_rt_period(void)
829 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
832 static inline u64 global_rt_runtime(void)
834 if (sysctl_sched_rt_runtime < 0)
837 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
840 #ifndef prepare_arch_switch
841 # define prepare_arch_switch(next) do { } while (0)
843 #ifndef finish_arch_switch
844 # define finish_arch_switch(prev) do { } while (0)
847 static inline int task_current(struct rq *rq, struct task_struct *p)
849 return rq->curr == p;
852 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
853 static inline int task_running(struct rq *rq, struct task_struct *p)
855 return task_current(rq, p);
858 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
862 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
864 #ifdef CONFIG_DEBUG_SPINLOCK
865 /* this is a valid case when another task releases the spinlock */
866 rq->lock.owner = current;
869 * If we are tracking spinlock dependencies then we have to
870 * fix up the runqueue lock - which gets 'carried over' from
873 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
875 spin_unlock_irq(&rq->lock);
878 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
879 static inline int task_running(struct rq *rq, struct task_struct *p)
884 return task_current(rq, p);
888 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
892 * We can optimise this out completely for !SMP, because the
893 * SMP rebalancing from interrupt is the only thing that cares
898 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
899 spin_unlock_irq(&rq->lock);
901 spin_unlock(&rq->lock);
905 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
909 * After ->oncpu is cleared, the task can be moved to a different CPU.
910 * We must ensure this doesn't happen until the switch is completely
916 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
920 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
923 * __task_rq_lock - lock the runqueue a given task resides on.
924 * Must be called interrupts disabled.
926 static inline struct rq *__task_rq_lock(struct task_struct *p)
930 struct rq *rq = task_rq(p);
931 spin_lock(&rq->lock);
932 if (likely(rq == task_rq(p)))
934 spin_unlock(&rq->lock);
939 * task_rq_lock - lock the runqueue a given task resides on and disable
940 * interrupts. Note the ordering: we can safely lookup the task_rq without
941 * explicitly disabling preemption.
943 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
949 local_irq_save(*flags);
951 spin_lock(&rq->lock);
952 if (likely(rq == task_rq(p)))
954 spin_unlock_irqrestore(&rq->lock, *flags);
958 void task_rq_unlock_wait(struct task_struct *p)
960 struct rq *rq = task_rq(p);
962 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
963 spin_unlock_wait(&rq->lock);
966 static void __task_rq_unlock(struct rq *rq)
969 spin_unlock(&rq->lock);
972 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
975 spin_unlock_irqrestore(&rq->lock, *flags);
979 * this_rq_lock - lock this runqueue and disable interrupts.
981 static struct rq *this_rq_lock(void)
988 spin_lock(&rq->lock);
993 #ifdef CONFIG_SCHED_HRTICK
995 * Use HR-timers to deliver accurate preemption points.
997 * Its all a bit involved since we cannot program an hrt while holding the
998 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1001 * When we get rescheduled we reprogram the hrtick_timer outside of the
1007 * - enabled by features
1008 * - hrtimer is actually high res
1010 static inline int hrtick_enabled(struct rq *rq)
1012 if (!sched_feat(HRTICK))
1014 if (!cpu_active(cpu_of(rq)))
1016 return hrtimer_is_hres_active(&rq->hrtick_timer);
1019 static void hrtick_clear(struct rq *rq)
1021 if (hrtimer_active(&rq->hrtick_timer))
1022 hrtimer_cancel(&rq->hrtick_timer);
1026 * High-resolution timer tick.
1027 * Runs from hardirq context with interrupts disabled.
1029 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1031 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1033 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1035 spin_lock(&rq->lock);
1036 update_rq_clock(rq);
1037 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1038 spin_unlock(&rq->lock);
1040 return HRTIMER_NORESTART;
1045 * called from hardirq (IPI) context
1047 static void __hrtick_start(void *arg)
1049 struct rq *rq = arg;
1051 spin_lock(&rq->lock);
1052 hrtimer_restart(&rq->hrtick_timer);
1053 rq->hrtick_csd_pending = 0;
1054 spin_unlock(&rq->lock);
1058 * Called to set the hrtick timer state.
1060 * called with rq->lock held and irqs disabled
1062 static void hrtick_start(struct rq *rq, u64 delay)
1064 struct hrtimer *timer = &rq->hrtick_timer;
1065 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
1067 hrtimer_set_expires(timer, time);
1069 if (rq == this_rq()) {
1070 hrtimer_restart(timer);
1071 } else if (!rq->hrtick_csd_pending) {
1072 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd);
1073 rq->hrtick_csd_pending = 1;
1078 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1080 int cpu = (int)(long)hcpu;
1083 case CPU_UP_CANCELED:
1084 case CPU_UP_CANCELED_FROZEN:
1085 case CPU_DOWN_PREPARE:
1086 case CPU_DOWN_PREPARE_FROZEN:
1088 case CPU_DEAD_FROZEN:
1089 hrtick_clear(cpu_rq(cpu));
1096 static __init void init_hrtick(void)
1098 hotcpu_notifier(hotplug_hrtick, 0);
1102 * Called to set the hrtick timer state.
1104 * called with rq->lock held and irqs disabled
1106 static void hrtick_start(struct rq *rq, u64 delay)
1108 hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), HRTIMER_MODE_REL);
1111 static inline void init_hrtick(void)
1114 #endif /* CONFIG_SMP */
1116 static void init_rq_hrtick(struct rq *rq)
1119 rq->hrtick_csd_pending = 0;
1121 rq->hrtick_csd.flags = 0;
1122 rq->hrtick_csd.func = __hrtick_start;
1123 rq->hrtick_csd.info = rq;
1126 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1127 rq->hrtick_timer.function = hrtick;
1128 rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
1130 #else /* CONFIG_SCHED_HRTICK */
1131 static inline void hrtick_clear(struct rq *rq)
1135 static inline void init_rq_hrtick(struct rq *rq)
1139 static inline void init_hrtick(void)
1142 #endif /* CONFIG_SCHED_HRTICK */
1145 * resched_task - mark a task 'to be rescheduled now'.
1147 * On UP this means the setting of the need_resched flag, on SMP it
1148 * might also involve a cross-CPU call to trigger the scheduler on
1153 #ifndef tsk_is_polling
1154 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1157 static void resched_task(struct task_struct *p)
1161 assert_spin_locked(&task_rq(p)->lock);
1163 if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
1166 set_tsk_thread_flag(p, TIF_NEED_RESCHED);
1169 if (cpu == smp_processor_id())
1172 /* NEED_RESCHED must be visible before we test polling */
1174 if (!tsk_is_polling(p))
1175 smp_send_reschedule(cpu);
1178 static void resched_cpu(int cpu)
1180 struct rq *rq = cpu_rq(cpu);
1181 unsigned long flags;
1183 if (!spin_trylock_irqsave(&rq->lock, flags))
1185 resched_task(cpu_curr(cpu));
1186 spin_unlock_irqrestore(&rq->lock, flags);
1191 * When add_timer_on() enqueues a timer into the timer wheel of an
1192 * idle CPU then this timer might expire before the next timer event
1193 * which is scheduled to wake up that CPU. In case of a completely
1194 * idle system the next event might even be infinite time into the
1195 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1196 * leaves the inner idle loop so the newly added timer is taken into
1197 * account when the CPU goes back to idle and evaluates the timer
1198 * wheel for the next timer event.
1200 void wake_up_idle_cpu(int cpu)
1202 struct rq *rq = cpu_rq(cpu);
1204 if (cpu == smp_processor_id())
1208 * This is safe, as this function is called with the timer
1209 * wheel base lock of (cpu) held. When the CPU is on the way
1210 * to idle and has not yet set rq->curr to idle then it will
1211 * be serialized on the timer wheel base lock and take the new
1212 * timer into account automatically.
1214 if (rq->curr != rq->idle)
1218 * We can set TIF_RESCHED on the idle task of the other CPU
1219 * lockless. The worst case is that the other CPU runs the
1220 * idle task through an additional NOOP schedule()
1222 set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
1224 /* NEED_RESCHED must be visible before we test polling */
1226 if (!tsk_is_polling(rq->idle))
1227 smp_send_reschedule(cpu);
1229 #endif /* CONFIG_NO_HZ */
1231 #else /* !CONFIG_SMP */
1232 static void resched_task(struct task_struct *p)
1234 assert_spin_locked(&task_rq(p)->lock);
1235 set_tsk_need_resched(p);
1237 #endif /* CONFIG_SMP */
1239 #if BITS_PER_LONG == 32
1240 # define WMULT_CONST (~0UL)
1242 # define WMULT_CONST (1UL << 32)
1245 #define WMULT_SHIFT 32
1248 * Shift right and round:
1250 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1253 * delta *= weight / lw
1255 static unsigned long
1256 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1257 struct load_weight *lw)
1261 if (!lw->inv_weight) {
1262 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1265 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1269 tmp = (u64)delta_exec * weight;
1271 * Check whether we'd overflow the 64-bit multiplication:
1273 if (unlikely(tmp > WMULT_CONST))
1274 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1277 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1279 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1282 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1288 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1295 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1296 * of tasks with abnormal "nice" values across CPUs the contribution that
1297 * each task makes to its run queue's load is weighted according to its
1298 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1299 * scaled version of the new time slice allocation that they receive on time
1303 #define WEIGHT_IDLEPRIO 2
1304 #define WMULT_IDLEPRIO (1 << 31)
1307 * Nice levels are multiplicative, with a gentle 10% change for every
1308 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1309 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1310 * that remained on nice 0.
1312 * The "10% effect" is relative and cumulative: from _any_ nice level,
1313 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1314 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1315 * If a task goes up by ~10% and another task goes down by ~10% then
1316 * the relative distance between them is ~25%.)
1318 static const int prio_to_weight[40] = {
1319 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1320 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1321 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1322 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1323 /* 0 */ 1024, 820, 655, 526, 423,
1324 /* 5 */ 335, 272, 215, 172, 137,
1325 /* 10 */ 110, 87, 70, 56, 45,
1326 /* 15 */ 36, 29, 23, 18, 15,
1330 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1332 * In cases where the weight does not change often, we can use the
1333 * precalculated inverse to speed up arithmetics by turning divisions
1334 * into multiplications:
1336 static const u32 prio_to_wmult[40] = {
1337 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1338 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1339 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1340 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1341 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1342 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1343 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1344 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1347 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
1350 * runqueue iterator, to support SMP load-balancing between different
1351 * scheduling classes, without having to expose their internal data
1352 * structures to the load-balancing proper:
1354 struct rq_iterator {
1356 struct task_struct *(*start)(void *);
1357 struct task_struct *(*next)(void *);
1361 static unsigned long
1362 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
1363 unsigned long max_load_move, struct sched_domain *sd,
1364 enum cpu_idle_type idle, int *all_pinned,
1365 int *this_best_prio, struct rq_iterator *iterator);
1368 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
1369 struct sched_domain *sd, enum cpu_idle_type idle,
1370 struct rq_iterator *iterator);
1373 #ifdef CONFIG_CGROUP_CPUACCT
1374 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1376 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1379 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1381 update_load_add(&rq->load, load);
1384 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1386 update_load_sub(&rq->load, load);
1389 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1390 typedef int (*tg_visitor)(struct task_group *, void *);
1393 * Iterate the full tree, calling @down when first entering a node and @up when
1394 * leaving it for the final time.
1396 static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
1398 struct task_group *parent, *child;
1402 parent = &root_task_group;
1404 ret = (*down)(parent, data);
1407 list_for_each_entry_rcu(child, &parent->children, siblings) {
1414 ret = (*up)(parent, data);
1419 parent = parent->parent;
1428 static int tg_nop(struct task_group *tg, void *data)
1435 static unsigned long source_load(int cpu, int type);
1436 static unsigned long target_load(int cpu, int type);
1437 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1439 static unsigned long cpu_avg_load_per_task(int cpu)
1441 struct rq *rq = cpu_rq(cpu);
1444 rq->avg_load_per_task = rq->load.weight / rq->nr_running;
1446 rq->avg_load_per_task = 0;
1448 return rq->avg_load_per_task;
1451 #ifdef CONFIG_FAIR_GROUP_SCHED
1453 static void __set_se_shares(struct sched_entity *se, unsigned long shares);
1456 * Calculate and set the cpu's group shares.
1459 update_group_shares_cpu(struct task_group *tg, int cpu,
1460 unsigned long sd_shares, unsigned long sd_rq_weight)
1462 unsigned long shares;
1463 unsigned long rq_weight;
1468 rq_weight = tg->cfs_rq[cpu]->rq_weight;
1471 * \Sum shares * rq_weight
1472 * shares = -----------------------
1476 shares = (sd_shares * rq_weight) / sd_rq_weight;
1477 shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
1479 if (abs(shares - tg->se[cpu]->load.weight) >
1480 sysctl_sched_shares_thresh) {
1481 struct rq *rq = cpu_rq(cpu);
1482 unsigned long flags;
1484 spin_lock_irqsave(&rq->lock, flags);
1485 tg->cfs_rq[cpu]->shares = shares;
1487 __set_se_shares(tg->se[cpu], shares);
1488 spin_unlock_irqrestore(&rq->lock, flags);
1493 * Re-compute the task group their per cpu shares over the given domain.
1494 * This needs to be done in a bottom-up fashion because the rq weight of a
1495 * parent group depends on the shares of its child groups.
1497 static int tg_shares_up(struct task_group *tg, void *data)
1499 unsigned long weight, rq_weight = 0;
1500 unsigned long shares = 0;
1501 struct sched_domain *sd = data;
1504 for_each_cpu(i, sched_domain_span(sd)) {
1506 * If there are currently no tasks on the cpu pretend there
1507 * is one of average load so that when a new task gets to
1508 * run here it will not get delayed by group starvation.
1510 weight = tg->cfs_rq[i]->load.weight;
1512 weight = NICE_0_LOAD;
1514 tg->cfs_rq[i]->rq_weight = weight;
1515 rq_weight += weight;
1516 shares += tg->cfs_rq[i]->shares;
1519 if ((!shares && rq_weight) || shares > tg->shares)
1520 shares = tg->shares;
1522 if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
1523 shares = tg->shares;
1525 for_each_cpu(i, sched_domain_span(sd))
1526 update_group_shares_cpu(tg, i, shares, rq_weight);
1532 * Compute the cpu's hierarchical load factor for each task group.
1533 * This needs to be done in a top-down fashion because the load of a child
1534 * group is a fraction of its parents load.
1536 static int tg_load_down(struct task_group *tg, void *data)
1539 long cpu = (long)data;
1542 load = cpu_rq(cpu)->load.weight;
1544 load = tg->parent->cfs_rq[cpu]->h_load;
1545 load *= tg->cfs_rq[cpu]->shares;
1546 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
1549 tg->cfs_rq[cpu]->h_load = load;
1554 static void update_shares(struct sched_domain *sd)
1556 u64 now = cpu_clock(raw_smp_processor_id());
1557 s64 elapsed = now - sd->last_update;
1559 if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
1560 sd->last_update = now;
1561 walk_tg_tree(tg_nop, tg_shares_up, sd);
1565 static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1567 spin_unlock(&rq->lock);
1569 spin_lock(&rq->lock);
1572 static void update_h_load(long cpu)
1574 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
1579 static inline void update_shares(struct sched_domain *sd)
1583 static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1591 #ifdef CONFIG_FAIR_GROUP_SCHED
1592 static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
1595 cfs_rq->shares = shares;
1600 #include "sched_stats.h"
1601 #include "sched_idletask.c"
1602 #include "sched_fair.c"
1603 #include "sched_rt.c"
1604 #ifdef CONFIG_SCHED_DEBUG
1605 # include "sched_debug.c"
1608 #define sched_class_highest (&rt_sched_class)
1609 #define for_each_class(class) \
1610 for (class = sched_class_highest; class; class = class->next)
1612 static void inc_nr_running(struct rq *rq)
1617 static void dec_nr_running(struct rq *rq)
1622 static void set_load_weight(struct task_struct *p)
1624 if (task_has_rt_policy(p)) {
1625 p->se.load.weight = prio_to_weight[0] * 2;
1626 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1631 * SCHED_IDLE tasks get minimal weight:
1633 if (p->policy == SCHED_IDLE) {
1634 p->se.load.weight = WEIGHT_IDLEPRIO;
1635 p->se.load.inv_weight = WMULT_IDLEPRIO;
1639 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1640 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1643 static void update_avg(u64 *avg, u64 sample)
1645 s64 diff = sample - *avg;
1649 static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
1651 sched_info_queued(p);
1652 p->sched_class->enqueue_task(rq, p, wakeup);
1656 static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
1658 if (sleep && p->se.last_wakeup) {
1659 update_avg(&p->se.avg_overlap,
1660 p->se.sum_exec_runtime - p->se.last_wakeup);
1661 p->se.last_wakeup = 0;
1664 sched_info_dequeued(p);
1665 p->sched_class->dequeue_task(rq, p, sleep);
1670 * __normal_prio - return the priority that is based on the static prio
1672 static inline int __normal_prio(struct task_struct *p)
1674 return p->static_prio;
1678 * Calculate the expected normal priority: i.e. priority
1679 * without taking RT-inheritance into account. Might be
1680 * boosted by interactivity modifiers. Changes upon fork,
1681 * setprio syscalls, and whenever the interactivity
1682 * estimator recalculates.
1684 static inline int normal_prio(struct task_struct *p)
1688 if (task_has_rt_policy(p))
1689 prio = MAX_RT_PRIO-1 - p->rt_priority;
1691 prio = __normal_prio(p);
1696 * Calculate the current priority, i.e. the priority
1697 * taken into account by the scheduler. This value might
1698 * be boosted by RT tasks, or might be boosted by
1699 * interactivity modifiers. Will be RT if the task got
1700 * RT-boosted. If not then it returns p->normal_prio.
1702 static int effective_prio(struct task_struct *p)
1704 p->normal_prio = normal_prio(p);
1706 * If we are RT tasks or we were boosted to RT priority,
1707 * keep the priority unchanged. Otherwise, update priority
1708 * to the normal priority:
1710 if (!rt_prio(p->prio))
1711 return p->normal_prio;
1716 * activate_task - move a task to the runqueue.
1718 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
1720 if (task_contributes_to_load(p))
1721 rq->nr_uninterruptible--;
1723 enqueue_task(rq, p, wakeup);
1728 * deactivate_task - remove a task from the runqueue.
1730 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
1732 if (task_contributes_to_load(p))
1733 rq->nr_uninterruptible++;
1735 dequeue_task(rq, p, sleep);
1740 * task_curr - is this task currently executing on a CPU?
1741 * @p: the task in question.
1743 inline int task_curr(const struct task_struct *p)
1745 return cpu_curr(task_cpu(p)) == p;
1748 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1750 set_task_rq(p, cpu);
1753 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1754 * successfuly executed on another CPU. We must ensure that updates of
1755 * per-task data have been completed by this moment.
1758 task_thread_info(p)->cpu = cpu;
1762 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1763 const struct sched_class *prev_class,
1764 int oldprio, int running)
1766 if (prev_class != p->sched_class) {
1767 if (prev_class->switched_from)
1768 prev_class->switched_from(rq, p, running);
1769 p->sched_class->switched_to(rq, p, running);
1771 p->sched_class->prio_changed(rq, p, oldprio, running);
1776 /* Used instead of source_load when we know the type == 0 */
1777 static unsigned long weighted_cpuload(const int cpu)
1779 return cpu_rq(cpu)->load.weight;
1783 * Is this task likely cache-hot:
1786 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1791 * Buddy candidates are cache hot:
1793 if (sched_feat(CACHE_HOT_BUDDY) &&
1794 (&p->se == cfs_rq_of(&p->se)->next ||
1795 &p->se == cfs_rq_of(&p->se)->last))
1798 if (p->sched_class != &fair_sched_class)
1801 if (sysctl_sched_migration_cost == -1)
1803 if (sysctl_sched_migration_cost == 0)
1806 delta = now - p->se.exec_start;
1808 return delta < (s64)sysctl_sched_migration_cost;
1812 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1814 int old_cpu = task_cpu(p);
1815 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
1816 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1817 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
1820 clock_offset = old_rq->clock - new_rq->clock;
1822 #ifdef CONFIG_SCHEDSTATS
1823 if (p->se.wait_start)
1824 p->se.wait_start -= clock_offset;
1825 if (p->se.sleep_start)
1826 p->se.sleep_start -= clock_offset;
1827 if (p->se.block_start)
1828 p->se.block_start -= clock_offset;
1829 if (old_cpu != new_cpu) {
1830 schedstat_inc(p, se.nr_migrations);
1831 if (task_hot(p, old_rq->clock, NULL))
1832 schedstat_inc(p, se.nr_forced2_migrations);
1835 p->se.vruntime -= old_cfsrq->min_vruntime -
1836 new_cfsrq->min_vruntime;
1838 __set_task_cpu(p, new_cpu);
1841 struct migration_req {
1842 struct list_head list;
1844 struct task_struct *task;
1847 struct completion done;
1851 * The task's runqueue lock must be held.
1852 * Returns true if you have to wait for migration thread.
1855 migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
1857 struct rq *rq = task_rq(p);
1860 * If the task is not on a runqueue (and not running), then
1861 * it is sufficient to simply update the task's cpu field.
1863 if (!p->se.on_rq && !task_running(rq, p)) {
1864 set_task_cpu(p, dest_cpu);
1868 init_completion(&req->done);
1870 req->dest_cpu = dest_cpu;
1871 list_add(&req->list, &rq->migration_queue);
1877 * wait_task_inactive - wait for a thread to unschedule.
1879 * If @match_state is nonzero, it's the @p->state value just checked and
1880 * not expected to change. If it changes, i.e. @p might have woken up,
1881 * then return zero. When we succeed in waiting for @p to be off its CPU,
1882 * we return a positive number (its total switch count). If a second call
1883 * a short while later returns the same number, the caller can be sure that
1884 * @p has remained unscheduled the whole time.
1886 * The caller must ensure that the task *will* unschedule sometime soon,
1887 * else this function might spin for a *long* time. This function can't
1888 * be called with interrupts off, or it may introduce deadlock with
1889 * smp_call_function() if an IPI is sent by the same process we are
1890 * waiting to become inactive.
1892 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
1894 unsigned long flags;
1901 * We do the initial early heuristics without holding
1902 * any task-queue locks at all. We'll only try to get
1903 * the runqueue lock when things look like they will
1909 * If the task is actively running on another CPU
1910 * still, just relax and busy-wait without holding
1913 * NOTE! Since we don't hold any locks, it's not
1914 * even sure that "rq" stays as the right runqueue!
1915 * But we don't care, since "task_running()" will
1916 * return false if the runqueue has changed and p
1917 * is actually now running somewhere else!
1919 while (task_running(rq, p)) {
1920 if (match_state && unlikely(p->state != match_state))
1926 * Ok, time to look more closely! We need the rq
1927 * lock now, to be *sure*. If we're wrong, we'll
1928 * just go back and repeat.
1930 rq = task_rq_lock(p, &flags);
1931 trace_sched_wait_task(rq, p);
1932 running = task_running(rq, p);
1933 on_rq = p->se.on_rq;
1935 if (!match_state || p->state == match_state)
1936 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
1937 task_rq_unlock(rq, &flags);
1940 * If it changed from the expected state, bail out now.
1942 if (unlikely(!ncsw))
1946 * Was it really running after all now that we
1947 * checked with the proper locks actually held?
1949 * Oops. Go back and try again..
1951 if (unlikely(running)) {
1957 * It's not enough that it's not actively running,
1958 * it must be off the runqueue _entirely_, and not
1961 * So if it wa still runnable (but just not actively
1962 * running right now), it's preempted, and we should
1963 * yield - it could be a while.
1965 if (unlikely(on_rq)) {
1966 schedule_timeout_uninterruptible(1);
1971 * Ahh, all good. It wasn't running, and it wasn't
1972 * runnable, which means that it will never become
1973 * running in the future either. We're all done!
1982 * kick_process - kick a running thread to enter/exit the kernel
1983 * @p: the to-be-kicked thread
1985 * Cause a process which is running on another CPU to enter
1986 * kernel-mode, without any delay. (to get signals handled.)
1988 * NOTE: this function doesnt have to take the runqueue lock,
1989 * because all it wants to ensure is that the remote task enters
1990 * the kernel. If the IPI races and the task has been migrated
1991 * to another CPU then no harm is done and the purpose has been
1994 void kick_process(struct task_struct *p)
2000 if ((cpu != smp_processor_id()) && task_curr(p))
2001 smp_send_reschedule(cpu);
2006 * Return a low guess at the load of a migration-source cpu weighted
2007 * according to the scheduling class and "nice" value.
2009 * We want to under-estimate the load of migration sources, to
2010 * balance conservatively.
2012 static unsigned long source_load(int cpu, int type)
2014 struct rq *rq = cpu_rq(cpu);
2015 unsigned long total = weighted_cpuload(cpu);
2017 if (type == 0 || !sched_feat(LB_BIAS))
2020 return min(rq->cpu_load[type-1], total);
2024 * Return a high guess at the load of a migration-target cpu weighted
2025 * according to the scheduling class and "nice" value.
2027 static unsigned long target_load(int cpu, int type)
2029 struct rq *rq = cpu_rq(cpu);
2030 unsigned long total = weighted_cpuload(cpu);
2032 if (type == 0 || !sched_feat(LB_BIAS))
2035 return max(rq->cpu_load[type-1], total);
2039 * find_idlest_group finds and returns the least busy CPU group within the
2042 static struct sched_group *
2043 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
2045 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
2046 unsigned long min_load = ULONG_MAX, this_load = 0;
2047 int load_idx = sd->forkexec_idx;
2048 int imbalance = 100 + (sd->imbalance_pct-100)/2;
2051 unsigned long load, avg_load;
2055 /* Skip over this group if it has no CPUs allowed */
2056 if (!cpumask_intersects(sched_group_cpus(group),
2060 local_group = cpumask_test_cpu(this_cpu,
2061 sched_group_cpus(group));
2063 /* Tally up the load of all CPUs in the group */
2066 for_each_cpu(i, sched_group_cpus(group)) {
2067 /* Bias balancing toward cpus of our domain */
2069 load = source_load(i, load_idx);
2071 load = target_load(i, load_idx);
2076 /* Adjust by relative CPU power of the group */
2077 avg_load = sg_div_cpu_power(group,
2078 avg_load * SCHED_LOAD_SCALE);
2081 this_load = avg_load;
2083 } else if (avg_load < min_load) {
2084 min_load = avg_load;
2087 } while (group = group->next, group != sd->groups);
2089 if (!idlest || 100*this_load < imbalance*min_load)
2095 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2098 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
2100 unsigned long load, min_load = ULONG_MAX;
2104 /* Traverse only the allowed CPUs */
2105 for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {
2106 load = weighted_cpuload(i);
2108 if (load < min_load || (load == min_load && i == this_cpu)) {
2118 * sched_balance_self: balance the current task (running on cpu) in domains
2119 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2122 * Balance, ie. select the least loaded group.
2124 * Returns the target CPU number, or the same CPU if no balancing is needed.
2126 * preempt must be disabled.
2128 static int sched_balance_self(int cpu, int flag)
2130 struct task_struct *t = current;
2131 struct sched_domain *tmp, *sd = NULL;
2133 for_each_domain(cpu, tmp) {
2135 * If power savings logic is enabled for a domain, stop there.
2137 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2139 if (tmp->flags & flag)
2147 struct sched_group *group;
2148 int new_cpu, weight;
2150 if (!(sd->flags & flag)) {
2155 group = find_idlest_group(sd, t, cpu);
2161 new_cpu = find_idlest_cpu(group, t, cpu);
2162 if (new_cpu == -1 || new_cpu == cpu) {
2163 /* Now try balancing at a lower domain level of cpu */
2168 /* Now try balancing at a lower domain level of new_cpu */
2170 weight = cpumask_weight(sched_domain_span(sd));
2172 for_each_domain(cpu, tmp) {
2173 if (weight <= cpumask_weight(sched_domain_span(tmp)))
2175 if (tmp->flags & flag)
2178 /* while loop will break here if sd == NULL */
2184 #endif /* CONFIG_SMP */
2187 * try_to_wake_up - wake up a thread
2188 * @p: the to-be-woken-up thread
2189 * @state: the mask of task states that can be woken
2190 * @sync: do a synchronous wakeup?
2192 * Put it on the run-queue if it's not already there. The "current"
2193 * thread is always on the run-queue (except when the actual
2194 * re-schedule is in progress), and as such you're allowed to do
2195 * the simpler "current->state = TASK_RUNNING" to mark yourself
2196 * runnable without the overhead of this.
2198 * returns failure only if the task is already active.
2200 static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
2202 int cpu, orig_cpu, this_cpu, success = 0;
2203 unsigned long flags;
2207 if (!sched_feat(SYNC_WAKEUPS))
2211 if (sched_feat(LB_WAKEUP_UPDATE)) {
2212 struct sched_domain *sd;
2214 this_cpu = raw_smp_processor_id();
2217 for_each_domain(this_cpu, sd) {
2218 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2227 rq = task_rq_lock(p, &flags);
2228 old_state = p->state;
2229 if (!(old_state & state))
2237 this_cpu = smp_processor_id();
2240 if (unlikely(task_running(rq, p)))
2243 cpu = p->sched_class->select_task_rq(p, sync);
2244 if (cpu != orig_cpu) {
2245 set_task_cpu(p, cpu);
2246 task_rq_unlock(rq, &flags);
2247 /* might preempt at this point */
2248 rq = task_rq_lock(p, &flags);
2249 old_state = p->state;
2250 if (!(old_state & state))
2255 this_cpu = smp_processor_id();
2259 #ifdef CONFIG_SCHEDSTATS
2260 schedstat_inc(rq, ttwu_count);
2261 if (cpu == this_cpu)
2262 schedstat_inc(rq, ttwu_local);
2264 struct sched_domain *sd;
2265 for_each_domain(this_cpu, sd) {
2266 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2267 schedstat_inc(sd, ttwu_wake_remote);
2272 #endif /* CONFIG_SCHEDSTATS */
2275 #endif /* CONFIG_SMP */
2276 schedstat_inc(p, se.nr_wakeups);
2278 schedstat_inc(p, se.nr_wakeups_sync);
2279 if (orig_cpu != cpu)
2280 schedstat_inc(p, se.nr_wakeups_migrate);
2281 if (cpu == this_cpu)
2282 schedstat_inc(p, se.nr_wakeups_local);
2284 schedstat_inc(p, se.nr_wakeups_remote);
2285 update_rq_clock(rq);
2286 activate_task(rq, p, 1);
2290 trace_sched_wakeup(rq, p);
2291 check_preempt_curr(rq, p, sync);
2293 p->state = TASK_RUNNING;
2295 if (p->sched_class->task_wake_up)
2296 p->sched_class->task_wake_up(rq, p);
2299 current->se.last_wakeup = current->se.sum_exec_runtime;
2301 task_rq_unlock(rq, &flags);
2306 int wake_up_process(struct task_struct *p)
2308 return try_to_wake_up(p, TASK_ALL, 0);
2310 EXPORT_SYMBOL(wake_up_process);
2312 int wake_up_state(struct task_struct *p, unsigned int state)
2314 return try_to_wake_up(p, state, 0);
2318 * Perform scheduler related setup for a newly forked process p.
2319 * p is forked by current.
2321 * __sched_fork() is basic setup used by init_idle() too:
2323 static void __sched_fork(struct task_struct *p)
2325 p->se.exec_start = 0;
2326 p->se.sum_exec_runtime = 0;
2327 p->se.prev_sum_exec_runtime = 0;
2328 p->se.last_wakeup = 0;
2329 p->se.avg_overlap = 0;
2331 #ifdef CONFIG_SCHEDSTATS
2332 p->se.wait_start = 0;
2333 p->se.sum_sleep_runtime = 0;
2334 p->se.sleep_start = 0;
2335 p->se.block_start = 0;
2336 p->se.sleep_max = 0;
2337 p->se.block_max = 0;
2339 p->se.slice_max = 0;
2343 INIT_LIST_HEAD(&p->rt.run_list);
2345 INIT_LIST_HEAD(&p->se.group_node);
2347 #ifdef CONFIG_PREEMPT_NOTIFIERS
2348 INIT_HLIST_HEAD(&p->preempt_notifiers);
2352 * We mark the process as running here, but have not actually
2353 * inserted it onto the runqueue yet. This guarantees that
2354 * nobody will actually run it, and a signal or other external
2355 * event cannot wake it up and insert it on the runqueue either.
2357 p->state = TASK_RUNNING;
2361 * fork()/clone()-time setup:
2363 void sched_fork(struct task_struct *p, int clone_flags)
2365 int cpu = get_cpu();
2370 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
2372 set_task_cpu(p, cpu);
2375 * Make sure we do not leak PI boosting priority to the child:
2377 p->prio = current->normal_prio;
2378 if (!rt_prio(p->prio))
2379 p->sched_class = &fair_sched_class;
2381 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2382 if (likely(sched_info_on()))
2383 memset(&p->sched_info, 0, sizeof(p->sched_info));
2385 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2388 #ifdef CONFIG_PREEMPT
2389 /* Want to start with kernel preemption disabled. */
2390 task_thread_info(p)->preempt_count = 1;
2396 * wake_up_new_task - wake up a newly created task for the first time.
2398 * This function will do some initial scheduler statistics housekeeping
2399 * that must be done for every newly created context, then puts the task
2400 * on the runqueue and wakes it.
2402 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2404 unsigned long flags;
2407 rq = task_rq_lock(p, &flags);
2408 BUG_ON(p->state != TASK_RUNNING);
2409 update_rq_clock(rq);
2411 p->prio = effective_prio(p);
2413 if (!p->sched_class->task_new || !current->se.on_rq) {
2414 activate_task(rq, p, 0);
2417 * Let the scheduling class do new task startup
2418 * management (if any):
2420 p->sched_class->task_new(rq, p);
2423 trace_sched_wakeup_new(rq, p);
2424 check_preempt_curr(rq, p, 0);
2426 if (p->sched_class->task_wake_up)
2427 p->sched_class->task_wake_up(rq, p);
2429 task_rq_unlock(rq, &flags);
2432 #ifdef CONFIG_PREEMPT_NOTIFIERS
2435 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2436 * @notifier: notifier struct to register
2438 void preempt_notifier_register(struct preempt_notifier *notifier)
2440 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2442 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2445 * preempt_notifier_unregister - no longer interested in preemption notifications
2446 * @notifier: notifier struct to unregister
2448 * This is safe to call from within a preemption notifier.
2450 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2452 hlist_del(¬ifier->link);
2454 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2456 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2458 struct preempt_notifier *notifier;
2459 struct hlist_node *node;
2461 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2462 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2466 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2467 struct task_struct *next)
2469 struct preempt_notifier *notifier;
2470 struct hlist_node *node;
2472 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2473 notifier->ops->sched_out(notifier, next);
2476 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2478 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2483 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2484 struct task_struct *next)
2488 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2491 * prepare_task_switch - prepare to switch tasks
2492 * @rq: the runqueue preparing to switch
2493 * @prev: the current task that is being switched out
2494 * @next: the task we are going to switch to.
2496 * This is called with the rq lock held and interrupts off. It must
2497 * be paired with a subsequent finish_task_switch after the context
2500 * prepare_task_switch sets up locking and calls architecture specific
2504 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2505 struct task_struct *next)
2507 fire_sched_out_preempt_notifiers(prev, next);
2508 prepare_lock_switch(rq, next);
2509 prepare_arch_switch(next);
2513 * finish_task_switch - clean up after a task-switch
2514 * @rq: runqueue associated with task-switch
2515 * @prev: the thread we just switched away from.
2517 * finish_task_switch must be called after the context switch, paired
2518 * with a prepare_task_switch call before the context switch.
2519 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2520 * and do any other architecture-specific cleanup actions.
2522 * Note that we may have delayed dropping an mm in context_switch(). If
2523 * so, we finish that here outside of the runqueue lock. (Doing it
2524 * with the lock held can cause deadlocks; see schedule() for
2527 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2528 __releases(rq->lock)
2530 struct mm_struct *mm = rq->prev_mm;
2536 * A task struct has one reference for the use as "current".
2537 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2538 * schedule one last time. The schedule call will never return, and
2539 * the scheduled task must drop that reference.
2540 * The test for TASK_DEAD must occur while the runqueue locks are
2541 * still held, otherwise prev could be scheduled on another cpu, die
2542 * there before we look at prev->state, and then the reference would
2544 * Manfred Spraul <manfred@colorfullife.com>
2546 prev_state = prev->state;
2547 finish_arch_switch(prev);
2548 finish_lock_switch(rq, prev);
2550 if (current->sched_class->post_schedule)
2551 current->sched_class->post_schedule(rq);
2554 fire_sched_in_preempt_notifiers(current);
2557 if (unlikely(prev_state == TASK_DEAD)) {
2559 * Remove function-return probe instances associated with this
2560 * task and put them back on the free list.
2562 kprobe_flush_task(prev);
2563 put_task_struct(prev);
2568 * schedule_tail - first thing a freshly forked thread must call.
2569 * @prev: the thread we just switched away from.
2571 asmlinkage void schedule_tail(struct task_struct *prev)
2572 __releases(rq->lock)
2574 struct rq *rq = this_rq();
2576 finish_task_switch(rq, prev);
2577 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2578 /* In this case, finish_task_switch does not reenable preemption */
2581 if (current->set_child_tid)
2582 put_user(task_pid_vnr(current), current->set_child_tid);
2586 * context_switch - switch to the new MM and the new
2587 * thread's register state.
2590 context_switch(struct rq *rq, struct task_struct *prev,
2591 struct task_struct *next)
2593 struct mm_struct *mm, *oldmm;
2595 prepare_task_switch(rq, prev, next);
2596 trace_sched_switch(rq, prev, next);
2598 oldmm = prev->active_mm;
2600 * For paravirt, this is coupled with an exit in switch_to to
2601 * combine the page table reload and the switch backend into
2604 arch_enter_lazy_cpu_mode();
2606 if (unlikely(!mm)) {
2607 next->active_mm = oldmm;
2608 atomic_inc(&oldmm->mm_count);
2609 enter_lazy_tlb(oldmm, next);
2611 switch_mm(oldmm, mm, next);
2613 if (unlikely(!prev->mm)) {
2614 prev->active_mm = NULL;
2615 rq->prev_mm = oldmm;
2618 * Since the runqueue lock will be released by the next
2619 * task (which is an invalid locking op but in the case
2620 * of the scheduler it's an obvious special-case), so we
2621 * do an early lockdep release here:
2623 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2624 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2627 /* Here we just switch the register state and the stack. */
2628 switch_to(prev, next, prev);
2632 * this_rq must be evaluated again because prev may have moved
2633 * CPUs since it called schedule(), thus the 'rq' on its stack
2634 * frame will be invalid.
2636 finish_task_switch(this_rq(), prev);
2640 * nr_running, nr_uninterruptible and nr_context_switches:
2642 * externally visible scheduler statistics: current number of runnable
2643 * threads, current number of uninterruptible-sleeping threads, total
2644 * number of context switches performed since bootup.
2646 unsigned long nr_running(void)
2648 unsigned long i, sum = 0;
2650 for_each_online_cpu(i)
2651 sum += cpu_rq(i)->nr_running;
2656 unsigned long nr_uninterruptible(void)
2658 unsigned long i, sum = 0;
2660 for_each_possible_cpu(i)
2661 sum += cpu_rq(i)->nr_uninterruptible;
2664 * Since we read the counters lockless, it might be slightly
2665 * inaccurate. Do not allow it to go below zero though:
2667 if (unlikely((long)sum < 0))
2673 unsigned long long nr_context_switches(void)
2676 unsigned long long sum = 0;
2678 for_each_possible_cpu(i)
2679 sum += cpu_rq(i)->nr_switches;
2684 unsigned long nr_iowait(void)
2686 unsigned long i, sum = 0;
2688 for_each_possible_cpu(i)
2689 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2694 unsigned long nr_active(void)
2696 unsigned long i, running = 0, uninterruptible = 0;
2698 for_each_online_cpu(i) {
2699 running += cpu_rq(i)->nr_running;
2700 uninterruptible += cpu_rq(i)->nr_uninterruptible;
2703 if (unlikely((long)uninterruptible < 0))
2704 uninterruptible = 0;
2706 return running + uninterruptible;
2710 * Update rq->cpu_load[] statistics. This function is usually called every
2711 * scheduler tick (TICK_NSEC).
2713 static void update_cpu_load(struct rq *this_rq)
2715 unsigned long this_load = this_rq->load.weight;
2718 this_rq->nr_load_updates++;
2720 /* Update our load: */
2721 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2722 unsigned long old_load, new_load;
2724 /* scale is effectively 1 << i now, and >> i divides by scale */
2726 old_load = this_rq->cpu_load[i];
2727 new_load = this_load;
2729 * Round up the averaging division if load is increasing. This
2730 * prevents us from getting stuck on 9 if the load is 10, for
2733 if (new_load > old_load)
2734 new_load += scale-1;
2735 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
2742 * double_rq_lock - safely lock two runqueues
2744 * Note this does not disable interrupts like task_rq_lock,
2745 * you need to do so manually before calling.
2747 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
2748 __acquires(rq1->lock)
2749 __acquires(rq2->lock)
2751 BUG_ON(!irqs_disabled());
2753 spin_lock(&rq1->lock);
2754 __acquire(rq2->lock); /* Fake it out ;) */
2757 spin_lock(&rq1->lock);
2758 spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
2760 spin_lock(&rq2->lock);
2761 spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
2764 update_rq_clock(rq1);
2765 update_rq_clock(rq2);
2769 * double_rq_unlock - safely unlock two runqueues
2771 * Note this does not restore interrupts like task_rq_unlock,
2772 * you need to do so manually after calling.
2774 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
2775 __releases(rq1->lock)
2776 __releases(rq2->lock)
2778 spin_unlock(&rq1->lock);
2780 spin_unlock(&rq2->lock);
2782 __release(rq2->lock);
2786 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2788 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
2789 __releases(this_rq->lock)
2790 __acquires(busiest->lock)
2791 __acquires(this_rq->lock)
2795 if (unlikely(!irqs_disabled())) {
2796 /* printk() doesn't work good under rq->lock */
2797 spin_unlock(&this_rq->lock);
2800 if (unlikely(!spin_trylock(&busiest->lock))) {
2801 if (busiest < this_rq) {
2802 spin_unlock(&this_rq->lock);
2803 spin_lock(&busiest->lock);
2804 spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING);
2807 spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING);
2812 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
2813 __releases(busiest->lock)
2815 spin_unlock(&busiest->lock);
2816 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
2820 * If dest_cpu is allowed for this process, migrate the task to it.
2821 * This is accomplished by forcing the cpu_allowed mask to only
2822 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2823 * the cpu_allowed mask is restored.
2825 static void sched_migrate_task(struct task_struct *p, int dest_cpu)
2827 struct migration_req req;
2828 unsigned long flags;
2831 rq = task_rq_lock(p, &flags);
2832 if (!cpu_isset(dest_cpu, p->cpus_allowed)
2833 || unlikely(!cpu_active(dest_cpu)))
2836 trace_sched_migrate_task(rq, p, dest_cpu);
2837 /* force the process onto the specified CPU */
2838 if (migrate_task(p, dest_cpu, &req)) {
2839 /* Need to wait for migration thread (might exit: take ref). */
2840 struct task_struct *mt = rq->migration_thread;
2842 get_task_struct(mt);
2843 task_rq_unlock(rq, &flags);
2844 wake_up_process(mt);
2845 put_task_struct(mt);
2846 wait_for_completion(&req.done);
2851 task_rq_unlock(rq, &flags);
2855 * sched_exec - execve() is a valuable balancing opportunity, because at
2856 * this point the task has the smallest effective memory and cache footprint.
2858 void sched_exec(void)
2860 int new_cpu, this_cpu = get_cpu();
2861 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
2863 if (new_cpu != this_cpu)
2864 sched_migrate_task(current, new_cpu);
2868 * pull_task - move a task from a remote runqueue to the local runqueue.
2869 * Both runqueues must be locked.
2871 static void pull_task(struct rq *src_rq, struct task_struct *p,
2872 struct rq *this_rq, int this_cpu)
2874 deactivate_task(src_rq, p, 0);
2875 set_task_cpu(p, this_cpu);
2876 activate_task(this_rq, p, 0);
2878 * Note that idle threads have a prio of MAX_PRIO, for this test
2879 * to be always true for them.
2881 check_preempt_curr(this_rq, p, 0);
2885 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2888 int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
2889 struct sched_domain *sd, enum cpu_idle_type idle,
2893 * We do not migrate tasks that are:
2894 * 1) running (obviously), or
2895 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2896 * 3) are cache-hot on their current CPU.
2898 if (!cpu_isset(this_cpu, p->cpus_allowed)) {
2899 schedstat_inc(p, se.nr_failed_migrations_affine);
2904 if (task_running(rq, p)) {
2905 schedstat_inc(p, se.nr_failed_migrations_running);
2910 * Aggressive migration if:
2911 * 1) task is cache cold, or
2912 * 2) too many balance attempts have failed.
2915 if (!task_hot(p, rq->clock, sd) ||
2916 sd->nr_balance_failed > sd->cache_nice_tries) {
2917 #ifdef CONFIG_SCHEDSTATS
2918 if (task_hot(p, rq->clock, sd)) {
2919 schedstat_inc(sd, lb_hot_gained[idle]);
2920 schedstat_inc(p, se.nr_forced_migrations);
2926 if (task_hot(p, rq->clock, sd)) {
2927 schedstat_inc(p, se.nr_failed_migrations_hot);
2933 static unsigned long
2934 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
2935 unsigned long max_load_move, struct sched_domain *sd,
2936 enum cpu_idle_type idle, int *all_pinned,
2937 int *this_best_prio, struct rq_iterator *iterator)
2939 int loops = 0, pulled = 0, pinned = 0;
2940 struct task_struct *p;
2941 long rem_load_move = max_load_move;
2943 if (max_load_move == 0)
2949 * Start the load-balancing iterator:
2951 p = iterator->start(iterator->arg);
2953 if (!p || loops++ > sysctl_sched_nr_migrate)
2956 if ((p->se.load.weight >> 1) > rem_load_move ||
2957 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
2958 p = iterator->next(iterator->arg);
2962 pull_task(busiest, p, this_rq, this_cpu);
2964 rem_load_move -= p->se.load.weight;
2967 * We only want to steal up to the prescribed amount of weighted load.
2969 if (rem_load_move > 0) {
2970 if (p->prio < *this_best_prio)
2971 *this_best_prio = p->prio;
2972 p = iterator->next(iterator->arg);
2977 * Right now, this is one of only two places pull_task() is called,
2978 * so we can safely collect pull_task() stats here rather than
2979 * inside pull_task().
2981 schedstat_add(sd, lb_gained[idle], pulled);
2984 *all_pinned = pinned;
2986 return max_load_move - rem_load_move;
2990 * move_tasks tries to move up to max_load_move weighted load from busiest to
2991 * this_rq, as part of a balancing operation within domain "sd".
2992 * Returns 1 if successful and 0 otherwise.
2994 * Called with both runqueues locked.
2996 static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
2997 unsigned long max_load_move,
2998 struct sched_domain *sd, enum cpu_idle_type idle,
3001 const struct sched_class *class = sched_class_highest;
3002 unsigned long total_load_moved = 0;
3003 int this_best_prio = this_rq->curr->prio;
3007 class->load_balance(this_rq, this_cpu, busiest,
3008 max_load_move - total_load_moved,
3009 sd, idle, all_pinned, &this_best_prio);
3010 class = class->next;
3012 if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
3015 } while (class && max_load_move > total_load_moved);
3017 return total_load_moved > 0;
3021 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3022 struct sched_domain *sd, enum cpu_idle_type idle,
3023 struct rq_iterator *iterator)
3025 struct task_struct *p = iterator->start(iterator->arg);
3029 if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3030 pull_task(busiest, p, this_rq, this_cpu);
3032 * Right now, this is only the second place pull_task()
3033 * is called, so we can safely collect pull_task()
3034 * stats here rather than inside pull_task().
3036 schedstat_inc(sd, lb_gained[idle]);
3040 p = iterator->next(iterator->arg);
3047 * move_one_task tries to move exactly one task from busiest to this_rq, as
3048 * part of active balancing operations within "domain".
3049 * Returns 1 if successful and 0 otherwise.
3051 * Called with both runqueues locked.
3053 static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3054 struct sched_domain *sd, enum cpu_idle_type idle)
3056 const struct sched_class *class;
3058 for (class = sched_class_highest; class; class = class->next)
3059 if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
3066 * find_busiest_group finds and returns the busiest CPU group within the
3067 * domain. It calculates and returns the amount of weighted load which
3068 * should be moved to restore balance via the imbalance parameter.
3070 static struct sched_group *
3071 find_busiest_group(struct sched_domain *sd, int this_cpu,
3072 unsigned long *imbalance, enum cpu_idle_type idle,
3073 int *sd_idle, const cpumask_t *cpus, int *balance)
3075 struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
3076 unsigned long max_load, avg_load, total_load, this_load, total_pwr;
3077 unsigned long max_pull;
3078 unsigned long busiest_load_per_task, busiest_nr_running;
3079 unsigned long this_load_per_task, this_nr_running;
3080 int load_idx, group_imb = 0;
3081 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3082 int power_savings_balance = 1;
3083 unsigned long leader_nr_running = 0, min_load_per_task = 0;
3084 unsigned long min_nr_running = ULONG_MAX;
3085 struct sched_group *group_min = NULL, *group_leader = NULL;
3088 max_load = this_load = total_load = total_pwr = 0;
3089 busiest_load_per_task = busiest_nr_running = 0;
3090 this_load_per_task = this_nr_running = 0;
3092 if (idle == CPU_NOT_IDLE)
3093 load_idx = sd->busy_idx;
3094 else if (idle == CPU_NEWLY_IDLE)
3095 load_idx = sd->newidle_idx;
3097 load_idx = sd->idle_idx;
3100 unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
3103 int __group_imb = 0;
3104 unsigned int balance_cpu = -1, first_idle_cpu = 0;
3105 unsigned long sum_nr_running, sum_weighted_load;
3106 unsigned long sum_avg_load_per_task;
3107 unsigned long avg_load_per_task;
3109 local_group = cpumask_test_cpu(this_cpu,
3110 sched_group_cpus(group));
3113 balance_cpu = cpumask_first(sched_group_cpus(group));
3115 /* Tally up the load of all CPUs in the group */
3116 sum_weighted_load = sum_nr_running = avg_load = 0;
3117 sum_avg_load_per_task = avg_load_per_task = 0;
3120 min_cpu_load = ~0UL;
3122 for_each_cpu_and(i, sched_group_cpus(group), cpus) {
3123 struct rq *rq = cpu_rq(i);
3125 if (*sd_idle && rq->nr_running)
3128 /* Bias balancing toward cpus of our domain */
3130 if (idle_cpu(i) && !first_idle_cpu) {
3135 load = target_load(i, load_idx);
3137 load = source_load(i, load_idx);
3138 if (load > max_cpu_load)
3139 max_cpu_load = load;
3140 if (min_cpu_load > load)
3141 min_cpu_load = load;
3145 sum_nr_running += rq->nr_running;
3146 sum_weighted_load += weighted_cpuload(i);
3148 sum_avg_load_per_task += cpu_avg_load_per_task(i);
3152 * First idle cpu or the first cpu(busiest) in this sched group
3153 * is eligible for doing load balancing at this and above
3154 * domains. In the newly idle case, we will allow all the cpu's
3155 * to do the newly idle load balance.
3157 if (idle != CPU_NEWLY_IDLE && local_group &&
3158 balance_cpu != this_cpu && balance) {
3163 total_load += avg_load;
3164 total_pwr += group->__cpu_power;
3166 /* Adjust by relative CPU power of the group */
3167 avg_load = sg_div_cpu_power(group,
3168 avg_load * SCHED_LOAD_SCALE);
3172 * Consider the group unbalanced when the imbalance is larger
3173 * than the average weight of two tasks.
3175 * APZ: with cgroup the avg task weight can vary wildly and
3176 * might not be a suitable number - should we keep a
3177 * normalized nr_running number somewhere that negates
3180 avg_load_per_task = sg_div_cpu_power(group,
3181 sum_avg_load_per_task * SCHED_LOAD_SCALE);
3183 if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
3186 group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
3189 this_load = avg_load;
3191 this_nr_running = sum_nr_running;
3192 this_load_per_task = sum_weighted_load;
3193 } else if (avg_load > max_load &&
3194 (sum_nr_running > group_capacity || __group_imb)) {
3195 max_load = avg_load;
3197 busiest_nr_running = sum_nr_running;
3198 busiest_load_per_task = sum_weighted_load;
3199 group_imb = __group_imb;
3202 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3204 * Busy processors will not participate in power savings
3207 if (idle == CPU_NOT_IDLE ||
3208 !(sd->flags & SD_POWERSAVINGS_BALANCE))
3212 * If the local group is idle or completely loaded
3213 * no need to do power savings balance at this domain
3215 if (local_group && (this_nr_running >= group_capacity ||
3217 power_savings_balance = 0;
3220 * If a group is already running at full capacity or idle,
3221 * don't include that group in power savings calculations
3223 if (!power_savings_balance || sum_nr_running >= group_capacity
3228 * Calculate the group which has the least non-idle load.
3229 * This is the group from where we need to pick up the load
3232 if ((sum_nr_running < min_nr_running) ||
3233 (sum_nr_running == min_nr_running &&
3234 cpumask_first(sched_group_cpus(group)) <
3235 cpumask_first(sched_group_cpus(group_min)))) {
3237 min_nr_running = sum_nr_running;
3238 min_load_per_task = sum_weighted_load /
3243 * Calculate the group which is almost near its
3244 * capacity but still has some space to pick up some load
3245 * from other group and save more power
3247 if (sum_nr_running <= group_capacity - 1) {
3248 if (sum_nr_running > leader_nr_running ||
3249 (sum_nr_running == leader_nr_running &&
3250 cpumask_first(sched_group_cpus(group)) >
3251 cpumask_first(sched_group_cpus(group_leader)))) {
3252 group_leader = group;
3253 leader_nr_running = sum_nr_running;
3258 group = group->next;
3259 } while (group != sd->groups);
3261 if (!busiest || this_load >= max_load || busiest_nr_running == 0)
3264 avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
3266 if (this_load >= avg_load ||
3267 100*max_load <= sd->imbalance_pct*this_load)
3270 busiest_load_per_task /= busiest_nr_running;
3272 busiest_load_per_task = min(busiest_load_per_task, avg_load);
3275 * We're trying to get all the cpus to the average_load, so we don't
3276 * want to push ourselves above the average load, nor do we wish to
3277 * reduce the max loaded cpu below the average load, as either of these
3278 * actions would just result in more rebalancing later, and ping-pong
3279 * tasks around. Thus we look for the minimum possible imbalance.
3280 * Negative imbalances (*we* are more loaded than anyone else) will
3281 * be counted as no imbalance for these purposes -- we can't fix that
3282 * by pulling tasks to us. Be careful of negative numbers as they'll
3283 * appear as very large values with unsigned longs.
3285 if (max_load <= busiest_load_per_task)
3289 * In the presence of smp nice balancing, certain scenarios can have
3290 * max load less than avg load(as we skip the groups at or below
3291 * its cpu_power, while calculating max_load..)
3293 if (max_load < avg_load) {
3295 goto small_imbalance;
3298 /* Don't want to pull so many tasks that a group would go idle */
3299 max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
3301 /* How much load to actually move to equalise the imbalance */
3302 *imbalance = min(max_pull * busiest->__cpu_power,
3303 (avg_load - this_load) * this->__cpu_power)
3307 * if *imbalance is less than the average load per runnable task
3308 * there is no gaurantee that any tasks will be moved so we'll have
3309 * a think about bumping its value to force at least one task to be
3312 if (*imbalance < busiest_load_per_task) {
3313 unsigned long tmp, pwr_now, pwr_move;
3317 pwr_move = pwr_now = 0;
3319 if (this_nr_running) {
3320 this_load_per_task /= this_nr_running;
3321 if (busiest_load_per_task > this_load_per_task)
3324 this_load_per_task = cpu_avg_load_per_task(this_cpu);
3326 if (max_load - this_load + busiest_load_per_task >=
3327 busiest_load_per_task * imbn) {
3328 *imbalance = busiest_load_per_task;
3333 * OK, we don't have enough imbalance to justify moving tasks,
3334 * however we may be able to increase total CPU power used by
3338 pwr_now += busiest->__cpu_power *
3339 min(busiest_load_per_task, max_load);
3340 pwr_now += this->__cpu_power *
3341 min(this_load_per_task, this_load);
3342 pwr_now /= SCHED_LOAD_SCALE;
3344 /* Amount of load we'd subtract */
3345 tmp = sg_div_cpu_power(busiest,
3346 busiest_load_per_task * SCHED_LOAD_SCALE);
3348 pwr_move += busiest->__cpu_power *
3349 min(busiest_load_per_task, max_load - tmp);
3351 /* Amount of load we'd add */
3352 if (max_load * busiest->__cpu_power <
3353 busiest_load_per_task * SCHED_LOAD_SCALE)
3354 tmp = sg_div_cpu_power(this,
3355 max_load * busiest->__cpu_power);
3357 tmp = sg_div_cpu_power(this,
3358 busiest_load_per_task * SCHED_LOAD_SCALE);
3359 pwr_move += this->__cpu_power *
3360 min(this_load_per_task, this_load + tmp);
3361 pwr_move /= SCHED_LOAD_SCALE;
3363 /* Move if we gain throughput */
3364 if (pwr_move > pwr_now)
3365 *imbalance = busiest_load_per_task;
3371 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3372 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
3375 if (this == group_leader && group_leader != group_min) {
3376 *imbalance = min_load_per_task;
3386 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3389 find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
3390 unsigned long imbalance, const cpumask_t *cpus)
3392 struct rq *busiest = NULL, *rq;
3393 unsigned long max_load = 0;
3396 for_each_cpu(i, sched_group_cpus(group)) {
3399 if (!cpu_isset(i, *cpus))
3403 wl = weighted_cpuload(i);
3405 if (rq->nr_running == 1 && wl > imbalance)
3408 if (wl > max_load) {
3418 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3419 * so long as it is large enough.
3421 #define MAX_PINNED_INTERVAL 512
3424 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3425 * tasks if there is an imbalance.
3427 static int load_balance(int this_cpu, struct rq *this_rq,
3428 struct sched_domain *sd, enum cpu_idle_type idle,
3429 int *balance, cpumask_t *cpus)
3431 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
3432 struct sched_group *group;
3433 unsigned long imbalance;
3435 unsigned long flags;
3440 * When power savings policy is enabled for the parent domain, idle
3441 * sibling can pick up load irrespective of busy siblings. In this case,
3442 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3443 * portraying it as CPU_NOT_IDLE.
3445 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
3446 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3449 schedstat_inc(sd, lb_count[idle]);
3453 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
3460 schedstat_inc(sd, lb_nobusyg[idle]);
3464 busiest = find_busiest_queue(group, idle, imbalance, cpus);
3466 schedstat_inc(sd, lb_nobusyq[idle]);
3470 BUG_ON(busiest == this_rq);
3472 schedstat_add(sd, lb_imbalance[idle], imbalance);
3475 if (busiest->nr_running > 1) {
3477 * Attempt to move tasks. If find_busiest_group has found
3478 * an imbalance but busiest->nr_running <= 1, the group is
3479 * still unbalanced. ld_moved simply stays zero, so it is
3480 * correctly treated as an imbalance.
3482 local_irq_save(flags);
3483 double_rq_lock(this_rq, busiest);
3484 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3485 imbalance, sd, idle, &all_pinned);
3486 double_rq_unlock(this_rq, busiest);
3487 local_irq_restore(flags);
3490 * some other cpu did the load balance for us.
3492 if (ld_moved && this_cpu != smp_processor_id())
3493 resched_cpu(this_cpu);
3495 /* All tasks on this runqueue were pinned by CPU affinity */
3496 if (unlikely(all_pinned)) {
3497 cpu_clear(cpu_of(busiest), *cpus);
3498 if (!cpus_empty(*cpus))
3505 schedstat_inc(sd, lb_failed[idle]);
3506 sd->nr_balance_failed++;
3508 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
3510 spin_lock_irqsave(&busiest->lock, flags);
3512 /* don't kick the migration_thread, if the curr
3513 * task on busiest cpu can't be moved to this_cpu
3515 if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) {
3516 spin_unlock_irqrestore(&busiest->lock, flags);
3518 goto out_one_pinned;
3521 if (!busiest->active_balance) {
3522 busiest->active_balance = 1;
3523 busiest->push_cpu = this_cpu;
3526 spin_unlock_irqrestore(&busiest->lock, flags);
3528 wake_up_process(busiest->migration_thread);
3531 * We've kicked active balancing, reset the failure
3534 sd->nr_balance_failed = sd->cache_nice_tries+1;
3537 sd->nr_balance_failed = 0;
3539 if (likely(!active_balance)) {
3540 /* We were unbalanced, so reset the balancing interval */
3541 sd->balance_interval = sd->min_interval;
3544 * If we've begun active balancing, start to back off. This
3545 * case may not be covered by the all_pinned logic if there
3546 * is only 1 task on the busy runqueue (because we don't call
3549 if (sd->balance_interval < sd->max_interval)
3550 sd->balance_interval *= 2;
3553 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3554 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3560 schedstat_inc(sd, lb_balanced[idle]);
3562 sd->nr_balance_failed = 0;
3565 /* tune up the balancing interval */
3566 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
3567 (sd->balance_interval < sd->max_interval))
3568 sd->balance_interval *= 2;
3570 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3571 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3582 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3583 * tasks if there is an imbalance.
3585 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3586 * this_rq is locked.
3589 load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd,
3592 struct sched_group *group;
3593 struct rq *busiest = NULL;
3594 unsigned long imbalance;
3602 * When power savings policy is enabled for the parent domain, idle
3603 * sibling can pick up load irrespective of busy siblings. In this case,
3604 * let the state of idle sibling percolate up as IDLE, instead of
3605 * portraying it as CPU_NOT_IDLE.
3607 if (sd->flags & SD_SHARE_CPUPOWER &&
3608 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3611 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
3613 update_shares_locked(this_rq, sd);
3614 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
3615 &sd_idle, cpus, NULL);
3617 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
3621 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
3623 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
3627 BUG_ON(busiest == this_rq);
3629 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
3632 if (busiest->nr_running > 1) {
3633 /* Attempt to move tasks */
3634 double_lock_balance(this_rq, busiest);
3635 /* this_rq->clock is already updated */
3636 update_rq_clock(busiest);
3637 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3638 imbalance, sd, CPU_NEWLY_IDLE,
3640 double_unlock_balance(this_rq, busiest);
3642 if (unlikely(all_pinned)) {
3643 cpu_clear(cpu_of(busiest), *cpus);
3644 if (!cpus_empty(*cpus))
3650 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
3651 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3652 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3655 sd->nr_balance_failed = 0;
3657 update_shares_locked(this_rq, sd);
3661 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
3662 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3663 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3665 sd->nr_balance_failed = 0;
3671 * idle_balance is called by schedule() if this_cpu is about to become
3672 * idle. Attempts to pull tasks from other CPUs.
3674 static void idle_balance(int this_cpu, struct rq *this_rq)
3676 struct sched_domain *sd;
3677 int pulled_task = -1;
3678 unsigned long next_balance = jiffies + HZ;
3681 for_each_domain(this_cpu, sd) {
3682 unsigned long interval;
3684 if (!(sd->flags & SD_LOAD_BALANCE))
3687 if (sd->flags & SD_BALANCE_NEWIDLE)
3688 /* If we've pulled tasks over stop searching: */
3689 pulled_task = load_balance_newidle(this_cpu, this_rq,
3692 interval = msecs_to_jiffies(sd->balance_interval);
3693 if (time_after(next_balance, sd->last_balance + interval))
3694 next_balance = sd->last_balance + interval;
3698 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
3700 * We are going idle. next_balance may be set based on
3701 * a busy processor. So reset next_balance.
3703 this_rq->next_balance = next_balance;
3708 * active_load_balance is run by migration threads. It pushes running tasks
3709 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3710 * running on each physical CPU where possible, and avoids physical /
3711 * logical imbalances.
3713 * Called with busiest_rq locked.
3715 static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
3717 int target_cpu = busiest_rq->push_cpu;
3718 struct sched_domain *sd;
3719 struct rq *target_rq;
3721 /* Is there any task to move? */
3722 if (busiest_rq->nr_running <= 1)
3725 target_rq = cpu_rq(target_cpu);
3728 * This condition is "impossible", if it occurs
3729 * we need to fix it. Originally reported by
3730 * Bjorn Helgaas on a 128-cpu setup.
3732 BUG_ON(busiest_rq == target_rq);
3734 /* move a task from busiest_rq to target_rq */
3735 double_lock_balance(busiest_rq, target_rq);
3736 update_rq_clock(busiest_rq);
3737 update_rq_clock(target_rq);
3739 /* Search for an sd spanning us and the target CPU. */
3740 for_each_domain(target_cpu, sd) {
3741 if ((sd->flags & SD_LOAD_BALANCE) &&
3742 cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
3747 schedstat_inc(sd, alb_count);
3749 if (move_one_task(target_rq, target_cpu, busiest_rq,
3751 schedstat_inc(sd, alb_pushed);
3753 schedstat_inc(sd, alb_failed);
3755 double_unlock_balance(busiest_rq, target_rq);
3760 atomic_t load_balancer;
3762 } nohz ____cacheline_aligned = {
3763 .load_balancer = ATOMIC_INIT(-1),
3764 .cpu_mask = CPU_MASK_NONE,
3768 * This routine will try to nominate the ilb (idle load balancing)
3769 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3770 * load balancing on behalf of all those cpus. If all the cpus in the system
3771 * go into this tickless mode, then there will be no ilb owner (as there is
3772 * no need for one) and all the cpus will sleep till the next wakeup event
3775 * For the ilb owner, tick is not stopped. And this tick will be used
3776 * for idle load balancing. ilb owner will still be part of
3779 * While stopping the tick, this cpu will become the ilb owner if there
3780 * is no other owner. And will be the owner till that cpu becomes busy
3781 * or if all cpus in the system stop their ticks at which point
3782 * there is no need for ilb owner.
3784 * When the ilb owner becomes busy, it nominates another owner, during the
3785 * next busy scheduler_tick()
3787 int select_nohz_load_balancer(int stop_tick)
3789 int cpu = smp_processor_id();
3792 cpu_set(cpu, nohz.cpu_mask);
3793 cpu_rq(cpu)->in_nohz_recently = 1;
3796 * If we are going offline and still the leader, give up!
3798 if (!cpu_active(cpu) &&
3799 atomic_read(&nohz.load_balancer) == cpu) {
3800 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3805 /* time for ilb owner also to sleep */
3806 if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
3807 if (atomic_read(&nohz.load_balancer) == cpu)
3808 atomic_set(&nohz.load_balancer, -1);
3812 if (atomic_read(&nohz.load_balancer) == -1) {
3813 /* make me the ilb owner */
3814 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
3816 } else if (atomic_read(&nohz.load_balancer) == cpu)
3819 if (!cpu_isset(cpu, nohz.cpu_mask))
3822 cpu_clear(cpu, nohz.cpu_mask);
3824 if (atomic_read(&nohz.load_balancer) == cpu)
3825 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3832 static DEFINE_SPINLOCK(balancing);
3835 * It checks each scheduling domain to see if it is due to be balanced,
3836 * and initiates a balancing operation if so.
3838 * Balancing parameters are set up in arch_init_sched_domains.
3840 static void rebalance_domains(int cpu, enum cpu_idle_type idle)
3843 struct rq *rq = cpu_rq(cpu);
3844 unsigned long interval;
3845 struct sched_domain *sd;
3846 /* Earliest time when we have to do rebalance again */
3847 unsigned long next_balance = jiffies + 60*HZ;
3848 int update_next_balance = 0;
3852 for_each_domain(cpu, sd) {
3853 if (!(sd->flags & SD_LOAD_BALANCE))
3856 interval = sd->balance_interval;
3857 if (idle != CPU_IDLE)
3858 interval *= sd->busy_factor;
3860 /* scale ms to jiffies */
3861 interval = msecs_to_jiffies(interval);
3862 if (unlikely(!interval))
3864 if (interval > HZ*NR_CPUS/10)
3865 interval = HZ*NR_CPUS/10;
3867 need_serialize = sd->flags & SD_SERIALIZE;
3869 if (need_serialize) {
3870 if (!spin_trylock(&balancing))
3874 if (time_after_eq(jiffies, sd->last_balance + interval)) {
3875 if (load_balance(cpu, rq, sd, idle, &balance, &tmp)) {
3877 * We've pulled tasks over so either we're no
3878 * longer idle, or one of our SMT siblings is
3881 idle = CPU_NOT_IDLE;
3883 sd->last_balance = jiffies;
3886 spin_unlock(&balancing);
3888 if (time_after(next_balance, sd->last_balance + interval)) {
3889 next_balance = sd->last_balance + interval;
3890 update_next_balance = 1;
3894 * Stop the load balance at this level. There is another
3895 * CPU in our sched group which is doing load balancing more
3903 * next_balance will be updated only when there is a need.
3904 * When the cpu is attached to null domain for ex, it will not be
3907 if (likely(update_next_balance))
3908 rq->next_balance = next_balance;
3912 * run_rebalance_domains is triggered when needed from the scheduler tick.
3913 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3914 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3916 static void run_rebalance_domains(struct softirq_action *h)
3918 int this_cpu = smp_processor_id();
3919 struct rq *this_rq = cpu_rq(this_cpu);
3920 enum cpu_idle_type idle = this_rq->idle_at_tick ?
3921 CPU_IDLE : CPU_NOT_IDLE;
3923 rebalance_domains(this_cpu, idle);
3927 * If this cpu is the owner for idle load balancing, then do the
3928 * balancing on behalf of the other idle cpus whose ticks are
3931 if (this_rq->idle_at_tick &&
3932 atomic_read(&nohz.load_balancer) == this_cpu) {
3933 cpumask_t cpus = nohz.cpu_mask;
3937 cpu_clear(this_cpu, cpus);
3938 for_each_cpu(balance_cpu, &cpus) {
3940 * If this cpu gets work to do, stop the load balancing
3941 * work being done for other cpus. Next load
3942 * balancing owner will pick it up.
3947 rebalance_domains(balance_cpu, CPU_IDLE);
3949 rq = cpu_rq(balance_cpu);
3950 if (time_after(this_rq->next_balance, rq->next_balance))
3951 this_rq->next_balance = rq->next_balance;
3958 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3960 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3961 * idle load balancing owner or decide to stop the periodic load balancing,
3962 * if the whole system is idle.
3964 static inline void trigger_load_balance(struct rq *rq, int cpu)
3968 * If we were in the nohz mode recently and busy at the current
3969 * scheduler tick, then check if we need to nominate new idle
3972 if (rq->in_nohz_recently && !rq->idle_at_tick) {
3973 rq->in_nohz_recently = 0;
3975 if (atomic_read(&nohz.load_balancer) == cpu) {
3976 cpu_clear(cpu, nohz.cpu_mask);
3977 atomic_set(&nohz.load_balancer, -1);
3980 if (atomic_read(&nohz.load_balancer) == -1) {
3982 * simple selection for now: Nominate the
3983 * first cpu in the nohz list to be the next
3986 * TBD: Traverse the sched domains and nominate
3987 * the nearest cpu in the nohz.cpu_mask.
3989 int ilb = first_cpu(nohz.cpu_mask);
3991 if (ilb < nr_cpu_ids)
3997 * If this cpu is idle and doing idle load balancing for all the
3998 * cpus with ticks stopped, is it time for that to stop?
4000 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
4001 cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
4007 * If this cpu is idle and the idle load balancing is done by
4008 * someone else, then no need raise the SCHED_SOFTIRQ
4010 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
4011 cpu_isset(cpu, nohz.cpu_mask))
4014 if (time_after_eq(jiffies, rq->next_balance))
4015 raise_softirq(SCHED_SOFTIRQ);
4018 #else /* CONFIG_SMP */
4021 * on UP we do not need to balance between CPUs:
4023 static inline void idle_balance(int cpu, struct rq *rq)
4029 DEFINE_PER_CPU(struct kernel_stat, kstat);
4031 EXPORT_PER_CPU_SYMBOL(kstat);
4034 * Return any ns on the sched_clock that have not yet been banked in
4035 * @p in case that task is currently running.
4037 unsigned long long task_delta_exec(struct task_struct *p)
4039 unsigned long flags;
4043 rq = task_rq_lock(p, &flags);
4045 if (task_current(rq, p)) {
4048 update_rq_clock(rq);
4049 delta_exec = rq->clock - p->se.exec_start;
4050 if ((s64)delta_exec > 0)
4054 task_rq_unlock(rq, &flags);
4060 * Account user cpu time to a process.
4061 * @p: the process that the cpu time gets accounted to
4062 * @cputime: the cpu time spent in user space since the last update
4064 void account_user_time(struct task_struct *p, cputime_t cputime)
4066 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4069 p->utime = cputime_add(p->utime, cputime);
4070 account_group_user_time(p, cputime);
4072 /* Add user time to cpustat. */
4073 tmp = cputime_to_cputime64(cputime);
4074 if (TASK_NICE(p) > 0)
4075 cpustat->nice = cputime64_add(cpustat->nice, tmp);
4077 cpustat->user = cputime64_add(cpustat->user, tmp);
4078 /* Account for user time used */
4079 acct_update_integrals(p);
4083 * Account guest cpu time to a process.
4084 * @p: the process that the cpu time gets accounted to
4085 * @cputime: the cpu time spent in virtual machine since the last update
4087 static void account_guest_time(struct task_struct *p, cputime_t cputime)
4090 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4092 tmp = cputime_to_cputime64(cputime);
4094 p->utime = cputime_add(p->utime, cputime);
4095 account_group_user_time(p, cputime);
4096 p->gtime = cputime_add(p->gtime, cputime);
4098 cpustat->user = cputime64_add(cpustat->user, tmp);
4099 cpustat->guest = cputime64_add(cpustat->guest, tmp);
4103 * Account scaled user cpu time to a process.
4104 * @p: the process that the cpu time gets accounted to
4105 * @cputime: the cpu time spent in user space since the last update
4107 void account_user_time_scaled(struct task_struct *p, cputime_t cputime)
4109 p->utimescaled = cputime_add(p->utimescaled, cputime);
4113 * Account system cpu time to a process.
4114 * @p: the process that the cpu time gets accounted to
4115 * @hardirq_offset: the offset to subtract from hardirq_count()
4116 * @cputime: the cpu time spent in kernel space since the last update
4118 void account_system_time(struct task_struct *p, int hardirq_offset,
4121 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4122 struct rq *rq = this_rq();
4125 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
4126 account_guest_time(p, cputime);
4130 p->stime = cputime_add(p->stime, cputime);
4131 account_group_system_time(p, cputime);
4133 /* Add system time to cpustat. */
4134 tmp = cputime_to_cputime64(cputime);
4135 if (hardirq_count() - hardirq_offset)
4136 cpustat->irq = cputime64_add(cpustat->irq, tmp);
4137 else if (softirq_count())
4138 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
4139 else if (p != rq->idle)
4140 cpustat->system = cputime64_add(cpustat->system, tmp);
4141 else if (atomic_read(&rq->nr_iowait) > 0)
4142 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
4144 cpustat->idle = cputime64_add(cpustat->idle, tmp);
4145 /* Account for system time used */
4146 acct_update_integrals(p);
4150 * Account scaled system cpu time to a process.
4151 * @p: the process that the cpu time gets accounted to
4152 * @hardirq_offset: the offset to subtract from hardirq_count()
4153 * @cputime: the cpu time spent in kernel space since the last update
4155 void account_system_time_scaled(struct task_struct *p, cputime_t cputime)
4157 p->stimescaled = cputime_add(p->stimescaled, cputime);
4161 * Account for involuntary wait time.
4162 * @p: the process from which the cpu time has been stolen
4163 * @steal: the cpu time spent in involuntary wait
4165 void account_steal_time(struct task_struct *p, cputime_t steal)
4167 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4168 cputime64_t tmp = cputime_to_cputime64(steal);
4169 struct rq *rq = this_rq();
4171 if (p == rq->idle) {
4172 p->stime = cputime_add(p->stime, steal);
4173 if (atomic_read(&rq->nr_iowait) > 0)
4174 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
4176 cpustat->idle = cputime64_add(cpustat->idle, tmp);
4178 cpustat->steal = cputime64_add(cpustat->steal, tmp);
4182 * Use precise platform statistics if available:
4184 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4185 cputime_t task_utime(struct task_struct *p)
4190 cputime_t task_stime(struct task_struct *p)
4195 cputime_t task_utime(struct task_struct *p)
4197 clock_t utime = cputime_to_clock_t(p->utime),
4198 total = utime + cputime_to_clock_t(p->stime);
4202 * Use CFS's precise accounting:
4204 temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
4208 do_div(temp, total);
4210 utime = (clock_t)temp;
4212 p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
4213 return p->prev_utime;
4216 cputime_t task_stime(struct task_struct *p)
4221 * Use CFS's precise accounting. (we subtract utime from
4222 * the total, to make sure the total observed by userspace
4223 * grows monotonically - apps rely on that):
4225 stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
4226 cputime_to_clock_t(task_utime(p));
4229 p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime));
4231 return p->prev_stime;
4235 inline cputime_t task_gtime(struct task_struct *p)
4241 * This function gets called by the timer code, with HZ frequency.
4242 * We call it with interrupts disabled.
4244 * It also gets called by the fork code, when changing the parent's
4247 void scheduler_tick(void)
4249 int cpu = smp_processor_id();
4250 struct rq *rq = cpu_rq(cpu);
4251 struct task_struct *curr = rq->curr;
4255 spin_lock(&rq->lock);
4256 update_rq_clock(rq);
4257 update_cpu_load(rq);
4258 curr->sched_class->task_tick(rq, curr, 0);
4259 spin_unlock(&rq->lock);
4262 rq->idle_at_tick = idle_cpu(cpu);
4263 trigger_load_balance(rq, cpu);
4267 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4268 defined(CONFIG_PREEMPT_TRACER))
4270 static inline unsigned long get_parent_ip(unsigned long addr)
4272 if (in_lock_functions(addr)) {
4273 addr = CALLER_ADDR2;
4274 if (in_lock_functions(addr))
4275 addr = CALLER_ADDR3;
4280 void __kprobes add_preempt_count(int val)
4282 #ifdef CONFIG_DEBUG_PREEMPT
4286 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4289 preempt_count() += val;
4290 #ifdef CONFIG_DEBUG_PREEMPT
4292 * Spinlock count overflowing soon?
4294 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
4297 if (preempt_count() == val)
4298 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4300 EXPORT_SYMBOL(add_preempt_count);
4302 void __kprobes sub_preempt_count(int val)
4304 #ifdef CONFIG_DEBUG_PREEMPT
4308 if (DEBUG_LOCKS_WARN_ON(val > preempt_count() - (!!kernel_locked())))
4311 * Is the spinlock portion underflowing?
4313 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
4314 !(preempt_count() & PREEMPT_MASK)))
4318 if (preempt_count() == val)
4319 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4320 preempt_count() -= val;
4322 EXPORT_SYMBOL(sub_preempt_count);
4327 * Print scheduling while atomic bug:
4329 static noinline void __schedule_bug(struct task_struct *prev)
4331 struct pt_regs *regs = get_irq_regs();
4333 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
4334 prev->comm, prev->pid, preempt_count());
4336 debug_show_held_locks(prev);
4338 if (irqs_disabled())
4339 print_irqtrace_events(prev);
4348 * Various schedule()-time debugging checks and statistics:
4350 static inline void schedule_debug(struct task_struct *prev)
4353 * Test if we are atomic. Since do_exit() needs to call into
4354 * schedule() atomically, we ignore that path for now.
4355 * Otherwise, whine if we are scheduling when we should not be.
4357 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
4358 __schedule_bug(prev);
4360 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
4362 schedstat_inc(this_rq(), sched_count);
4363 #ifdef CONFIG_SCHEDSTATS
4364 if (unlikely(prev->lock_depth >= 0)) {
4365 schedstat_inc(this_rq(), bkl_count);
4366 schedstat_inc(prev, sched_info.bkl_count);
4372 * Pick up the highest-prio task:
4374 static inline struct task_struct *
4375 pick_next_task(struct rq *rq, struct task_struct *prev)
4377 const struct sched_class *class;
4378 struct task_struct *p;
4381 * Optimization: we know that if all tasks are in
4382 * the fair class we can call that function directly:
4384 if (likely(rq->nr_running == rq->cfs.nr_running)) {
4385 p = fair_sched_class.pick_next_task(rq);
4390 class = sched_class_highest;
4392 p = class->pick_next_task(rq);
4396 * Will never be NULL as the idle class always
4397 * returns a non-NULL p:
4399 class = class->next;
4404 * schedule() is the main scheduler function.
4406 asmlinkage void __sched schedule(void)
4408 struct task_struct *prev, *next;
4409 unsigned long *switch_count;
4415 cpu = smp_processor_id();
4419 switch_count = &prev->nivcsw;
4421 release_kernel_lock(prev);
4422 need_resched_nonpreemptible:
4424 schedule_debug(prev);
4426 if (sched_feat(HRTICK))
4429 spin_lock_irq(&rq->lock);
4430 update_rq_clock(rq);
4431 clear_tsk_need_resched(prev);
4433 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
4434 if (unlikely(signal_pending_state(prev->state, prev)))
4435 prev->state = TASK_RUNNING;
4437 deactivate_task(rq, prev, 1);
4438 switch_count = &prev->nvcsw;
4442 if (prev->sched_class->pre_schedule)
4443 prev->sched_class->pre_schedule(rq, prev);
4446 if (unlikely(!rq->nr_running))
4447 idle_balance(cpu, rq);
4449 prev->sched_class->put_prev_task(rq, prev);
4450 next = pick_next_task(rq, prev);
4452 if (likely(prev != next)) {
4453 sched_info_switch(prev, next);
4459 context_switch(rq, prev, next); /* unlocks the rq */
4461 * the context switch might have flipped the stack from under
4462 * us, hence refresh the local variables.
4464 cpu = smp_processor_id();
4467 spin_unlock_irq(&rq->lock);
4469 if (unlikely(reacquire_kernel_lock(current) < 0))
4470 goto need_resched_nonpreemptible;
4472 preempt_enable_no_resched();
4473 if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
4476 EXPORT_SYMBOL(schedule);
4478 #ifdef CONFIG_PREEMPT
4480 * this is the entry point to schedule() from in-kernel preemption
4481 * off of preempt_enable. Kernel preemptions off return from interrupt
4482 * occur there and call schedule directly.
4484 asmlinkage void __sched preempt_schedule(void)
4486 struct thread_info *ti = current_thread_info();
4489 * If there is a non-zero preempt_count or interrupts are disabled,
4490 * we do not want to preempt the current task. Just return..
4492 if (likely(ti->preempt_count || irqs_disabled()))
4496 add_preempt_count(PREEMPT_ACTIVE);
4498 sub_preempt_count(PREEMPT_ACTIVE);
4501 * Check again in case we missed a preemption opportunity
4502 * between schedule and now.
4505 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
4507 EXPORT_SYMBOL(preempt_schedule);
4510 * this is the entry point to schedule() from kernel preemption
4511 * off of irq context.
4512 * Note, that this is called and return with irqs disabled. This will
4513 * protect us against recursive calling from irq.
4515 asmlinkage void __sched preempt_schedule_irq(void)
4517 struct thread_info *ti = current_thread_info();
4519 /* Catch callers which need to be fixed */
4520 BUG_ON(ti->preempt_count || !irqs_disabled());
4523 add_preempt_count(PREEMPT_ACTIVE);
4526 local_irq_disable();
4527 sub_preempt_count(PREEMPT_ACTIVE);
4530 * Check again in case we missed a preemption opportunity
4531 * between schedule and now.
4534 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
4537 #endif /* CONFIG_PREEMPT */
4539 int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
4542 return try_to_wake_up(curr->private, mode, sync);
4544 EXPORT_SYMBOL(default_wake_function);
4547 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4548 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4549 * number) then we wake all the non-exclusive tasks and one exclusive task.
4551 * There are circumstances in which we can try to wake a task which has already
4552 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4553 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4555 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
4556 int nr_exclusive, int sync, void *key)
4558 wait_queue_t *curr, *next;
4560 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
4561 unsigned flags = curr->flags;
4563 if (curr->func(curr, mode, sync, key) &&
4564 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
4570 * __wake_up - wake up threads blocked on a waitqueue.
4572 * @mode: which threads
4573 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4574 * @key: is directly passed to the wakeup function
4576 void __wake_up(wait_queue_head_t *q, unsigned int mode,
4577 int nr_exclusive, void *key)
4579 unsigned long flags;
4581 spin_lock_irqsave(&q->lock, flags);
4582 __wake_up_common(q, mode, nr_exclusive, 0, key);
4583 spin_unlock_irqrestore(&q->lock, flags);
4585 EXPORT_SYMBOL(__wake_up);
4588 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4590 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
4592 __wake_up_common(q, mode, 1, 0, NULL);
4596 * __wake_up_sync - wake up threads blocked on a waitqueue.
4598 * @mode: which threads
4599 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4601 * The sync wakeup differs that the waker knows that it will schedule
4602 * away soon, so while the target thread will be woken up, it will not
4603 * be migrated to another CPU - ie. the two threads are 'synchronized'
4604 * with each other. This can prevent needless bouncing between CPUs.
4606 * On UP it can prevent extra preemption.
4609 __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
4611 unsigned long flags;
4617 if (unlikely(!nr_exclusive))
4620 spin_lock_irqsave(&q->lock, flags);
4621 __wake_up_common(q, mode, nr_exclusive, sync, NULL);
4622 spin_unlock_irqrestore(&q->lock, flags);
4624 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
4627 * complete: - signals a single thread waiting on this completion
4628 * @x: holds the state of this particular completion
4630 * This will wake up a single thread waiting on this completion. Threads will be
4631 * awakened in the same order in which they were queued.
4633 * See also complete_all(), wait_for_completion() and related routines.
4635 void complete(struct completion *x)
4637 unsigned long flags;
4639 spin_lock_irqsave(&x->wait.lock, flags);
4641 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
4642 spin_unlock_irqrestore(&x->wait.lock, flags);
4644 EXPORT_SYMBOL(complete);
4647 * complete_all: - signals all threads waiting on this completion
4648 * @x: holds the state of this particular completion
4650 * This will wake up all threads waiting on this particular completion event.
4652 void complete_all(struct completion *x)
4654 unsigned long flags;
4656 spin_lock_irqsave(&x->wait.lock, flags);
4657 x->done += UINT_MAX/2;
4658 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
4659 spin_unlock_irqrestore(&x->wait.lock, flags);
4661 EXPORT_SYMBOL(complete_all);
4663 static inline long __sched
4664 do_wait_for_common(struct completion *x, long timeout, int state)
4667 DECLARE_WAITQUEUE(wait, current);
4669 wait.flags |= WQ_FLAG_EXCLUSIVE;
4670 __add_wait_queue_tail(&x->wait, &wait);
4672 if (signal_pending_state(state, current)) {
4673 timeout = -ERESTARTSYS;
4676 __set_current_state(state);
4677 spin_unlock_irq(&x->wait.lock);
4678 timeout = schedule_timeout(timeout);
4679 spin_lock_irq(&x->wait.lock);
4680 } while (!x->done && timeout);
4681 __remove_wait_queue(&x->wait, &wait);
4686 return timeout ?: 1;
4690 wait_for_common(struct completion *x, long timeout, int state)
4694 spin_lock_irq(&x->wait.lock);
4695 timeout = do_wait_for_common(x, timeout, state);
4696 spin_unlock_irq(&x->wait.lock);
4701 * wait_for_completion: - waits for completion of a task
4702 * @x: holds the state of this particular completion
4704 * This waits to be signaled for completion of a specific task. It is NOT
4705 * interruptible and there is no timeout.
4707 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4708 * and interrupt capability. Also see complete().
4710 void __sched wait_for_completion(struct completion *x)
4712 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
4714 EXPORT_SYMBOL(wait_for_completion);
4717 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4718 * @x: holds the state of this particular completion
4719 * @timeout: timeout value in jiffies
4721 * This waits for either a completion of a specific task to be signaled or for a
4722 * specified timeout to expire. The timeout is in jiffies. It is not
4725 unsigned long __sched
4726 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
4728 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
4730 EXPORT_SYMBOL(wait_for_completion_timeout);
4733 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4734 * @x: holds the state of this particular completion
4736 * This waits for completion of a specific task to be signaled. It is
4739 int __sched wait_for_completion_interruptible(struct completion *x)
4741 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
4742 if (t == -ERESTARTSYS)
4746 EXPORT_SYMBOL(wait_for_completion_interruptible);
4749 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4750 * @x: holds the state of this particular completion
4751 * @timeout: timeout value in jiffies
4753 * This waits for either a completion of a specific task to be signaled or for a
4754 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4756 unsigned long __sched
4757 wait_for_completion_interruptible_timeout(struct completion *x,
4758 unsigned long timeout)
4760 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
4762 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
4765 * wait_for_completion_killable: - waits for completion of a task (killable)
4766 * @x: holds the state of this particular completion
4768 * This waits to be signaled for completion of a specific task. It can be
4769 * interrupted by a kill signal.
4771 int __sched wait_for_completion_killable(struct completion *x)
4773 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
4774 if (t == -ERESTARTSYS)
4778 EXPORT_SYMBOL(wait_for_completion_killable);
4781 * try_wait_for_completion - try to decrement a completion without blocking
4782 * @x: completion structure
4784 * Returns: 0 if a decrement cannot be done without blocking
4785 * 1 if a decrement succeeded.
4787 * If a completion is being used as a counting completion,
4788 * attempt to decrement the counter without blocking. This
4789 * enables us to avoid waiting if the resource the completion
4790 * is protecting is not available.
4792 bool try_wait_for_completion(struct completion *x)
4796 spin_lock_irq(&x->wait.lock);
4801 spin_unlock_irq(&x->wait.lock);
4804 EXPORT_SYMBOL(try_wait_for_completion);
4807 * completion_done - Test to see if a completion has any waiters
4808 * @x: completion structure
4810 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4811 * 1 if there are no waiters.
4814 bool completion_done(struct completion *x)
4818 spin_lock_irq(&x->wait.lock);
4821 spin_unlock_irq(&x->wait.lock);
4824 EXPORT_SYMBOL(completion_done);
4827 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
4829 unsigned long flags;
4832 init_waitqueue_entry(&wait, current);
4834 __set_current_state(state);
4836 spin_lock_irqsave(&q->lock, flags);
4837 __add_wait_queue(q, &wait);
4838 spin_unlock(&q->lock);
4839 timeout = schedule_timeout(timeout);
4840 spin_lock_irq(&q->lock);
4841 __remove_wait_queue(q, &wait);
4842 spin_unlock_irqrestore(&q->lock, flags);
4847 void __sched interruptible_sleep_on(wait_queue_head_t *q)
4849 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4851 EXPORT_SYMBOL(interruptible_sleep_on);
4854 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
4856 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
4858 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
4860 void __sched sleep_on(wait_queue_head_t *q)
4862 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
4864 EXPORT_SYMBOL(sleep_on);
4866 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
4868 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
4870 EXPORT_SYMBOL(sleep_on_timeout);
4872 #ifdef CONFIG_RT_MUTEXES
4875 * rt_mutex_setprio - set the current priority of a task
4877 * @prio: prio value (kernel-internal form)
4879 * This function changes the 'effective' priority of a task. It does
4880 * not touch ->normal_prio like __setscheduler().
4882 * Used by the rt_mutex code to implement priority inheritance logic.
4884 void rt_mutex_setprio(struct task_struct *p, int prio)
4886 unsigned long flags;
4887 int oldprio, on_rq, running;
4889 const struct sched_class *prev_class = p->sched_class;
4891 BUG_ON(prio < 0 || prio > MAX_PRIO);
4893 rq = task_rq_lock(p, &flags);
4894 update_rq_clock(rq);
4897 on_rq = p->se.on_rq;
4898 running = task_current(rq, p);
4900 dequeue_task(rq, p, 0);
4902 p->sched_class->put_prev_task(rq, p);
4905 p->sched_class = &rt_sched_class;
4907 p->sched_class = &fair_sched_class;
4912 p->sched_class->set_curr_task(rq);
4914 enqueue_task(rq, p, 0);
4916 check_class_changed(rq, p, prev_class, oldprio, running);
4918 task_rq_unlock(rq, &flags);
4923 void set_user_nice(struct task_struct *p, long nice)
4925 int old_prio, delta, on_rq;
4926 unsigned long flags;
4929 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
4932 * We have to be careful, if called from sys_setpriority(),
4933 * the task might be in the middle of scheduling on another CPU.
4935 rq = task_rq_lock(p, &flags);
4936 update_rq_clock(rq);
4938 * The RT priorities are set via sched_setscheduler(), but we still
4939 * allow the 'normal' nice value to be set - but as expected
4940 * it wont have any effect on scheduling until the task is
4941 * SCHED_FIFO/SCHED_RR:
4943 if (task_has_rt_policy(p)) {
4944 p->static_prio = NICE_TO_PRIO(nice);
4947 on_rq = p->se.on_rq;
4949 dequeue_task(rq, p, 0);
4951 p->static_prio = NICE_TO_PRIO(nice);
4954 p->prio = effective_prio(p);
4955 delta = p->prio - old_prio;
4958 enqueue_task(rq, p, 0);
4960 * If the task increased its priority or is running and
4961 * lowered its priority, then reschedule its CPU:
4963 if (delta < 0 || (delta > 0 && task_running(rq, p)))
4964 resched_task(rq->curr);
4967 task_rq_unlock(rq, &flags);
4969 EXPORT_SYMBOL(set_user_nice);
4972 * can_nice - check if a task can reduce its nice value
4976 int can_nice(const struct task_struct *p, const int nice)
4978 /* convert nice value [19,-20] to rlimit style value [1,40] */
4979 int nice_rlim = 20 - nice;
4981 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
4982 capable(CAP_SYS_NICE));
4985 #ifdef __ARCH_WANT_SYS_NICE
4988 * sys_nice - change the priority of the current process.
4989 * @increment: priority increment
4991 * sys_setpriority is a more generic, but much slower function that
4992 * does similar things.
4994 asmlinkage long sys_nice(int increment)
4999 * Setpriority might change our priority at the same moment.
5000 * We don't have to worry. Conceptually one call occurs first
5001 * and we have a single winner.
5003 if (increment < -40)
5008 nice = PRIO_TO_NICE(current->static_prio) + increment;
5014 if (increment < 0 && !can_nice(current, nice))
5017 retval = security_task_setnice(current, nice);
5021 set_user_nice(current, nice);
5028 * task_prio - return the priority value of a given task.
5029 * @p: the task in question.
5031 * This is the priority value as seen by users in /proc.
5032 * RT tasks are offset by -200. Normal tasks are centered
5033 * around 0, value goes from -16 to +15.
5035 int task_prio(const struct task_struct *p)
5037 return p->prio - MAX_RT_PRIO;
5041 * task_nice - return the nice value of a given task.
5042 * @p: the task in question.
5044 int task_nice(const struct task_struct *p)
5046 return TASK_NICE(p);
5048 EXPORT_SYMBOL(task_nice);
5051 * idle_cpu - is a given cpu idle currently?
5052 * @cpu: the processor in question.
5054 int idle_cpu(int cpu)
5056 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
5060 * idle_task - return the idle task for a given cpu.
5061 * @cpu: the processor in question.
5063 struct task_struct *idle_task(int cpu)
5065 return cpu_rq(cpu)->idle;
5069 * find_process_by_pid - find a process with a matching PID value.
5070 * @pid: the pid in question.
5072 static struct task_struct *find_process_by_pid(pid_t pid)
5074 return pid ? find_task_by_vpid(pid) : current;
5077 /* Actually do priority change: must hold rq lock. */
5079 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
5081 BUG_ON(p->se.on_rq);
5084 switch (p->policy) {
5088 p->sched_class = &fair_sched_class;
5092 p->sched_class = &rt_sched_class;
5096 p->rt_priority = prio;
5097 p->normal_prio = normal_prio(p);
5098 /* we are holding p->pi_lock already */
5099 p->prio = rt_mutex_getprio(p);
5103 static int __sched_setscheduler(struct task_struct *p, int policy,
5104 struct sched_param *param, bool user)
5106 int retval, oldprio, oldpolicy = -1, on_rq, running;
5107 unsigned long flags;
5108 const struct sched_class *prev_class = p->sched_class;
5111 /* may grab non-irq protected spin_locks */
5112 BUG_ON(in_interrupt());
5114 /* double check policy once rq lock held */
5116 policy = oldpolicy = p->policy;
5117 else if (policy != SCHED_FIFO && policy != SCHED_RR &&
5118 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
5119 policy != SCHED_IDLE)
5122 * Valid priorities for SCHED_FIFO and SCHED_RR are
5123 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5124 * SCHED_BATCH and SCHED_IDLE is 0.
5126 if (param->sched_priority < 0 ||
5127 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
5128 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
5130 if (rt_policy(policy) != (param->sched_priority != 0))
5134 * Allow unprivileged RT tasks to decrease priority:
5136 if (user && !capable(CAP_SYS_NICE)) {
5137 if (rt_policy(policy)) {
5138 unsigned long rlim_rtprio;
5140 if (!lock_task_sighand(p, &flags))
5142 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
5143 unlock_task_sighand(p, &flags);
5145 /* can't set/change the rt policy */
5146 if (policy != p->policy && !rlim_rtprio)
5149 /* can't increase priority */
5150 if (param->sched_priority > p->rt_priority &&
5151 param->sched_priority > rlim_rtprio)
5155 * Like positive nice levels, dont allow tasks to
5156 * move out of SCHED_IDLE either:
5158 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
5161 /* can't change other user's priorities */
5162 if ((current->euid != p->euid) &&
5163 (current->euid != p->uid))
5168 #ifdef CONFIG_RT_GROUP_SCHED
5170 * Do not allow realtime tasks into groups that have no runtime
5173 if (rt_bandwidth_enabled() && rt_policy(policy) &&
5174 task_group(p)->rt_bandwidth.rt_runtime == 0)
5178 retval = security_task_setscheduler(p, policy, param);
5184 * make sure no PI-waiters arrive (or leave) while we are
5185 * changing the priority of the task:
5187 spin_lock_irqsave(&p->pi_lock, flags);
5189 * To be able to change p->policy safely, the apropriate
5190 * runqueue lock must be held.
5192 rq = __task_rq_lock(p);
5193 /* recheck policy now with rq lock held */
5194 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
5195 policy = oldpolicy = -1;
5196 __task_rq_unlock(rq);
5197 spin_unlock_irqrestore(&p->pi_lock, flags);
5200 update_rq_clock(rq);
5201 on_rq = p->se.on_rq;
5202 running = task_current(rq, p);
5204 deactivate_task(rq, p, 0);
5206 p->sched_class->put_prev_task(rq, p);
5209 __setscheduler(rq, p, policy, param->sched_priority);
5212 p->sched_class->set_curr_task(rq);
5214 activate_task(rq, p, 0);
5216 check_class_changed(rq, p, prev_class, oldprio, running);
5218 __task_rq_unlock(rq);
5219 spin_unlock_irqrestore(&p->pi_lock, flags);
5221 rt_mutex_adjust_pi(p);
5227 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5228 * @p: the task in question.
5229 * @policy: new policy.
5230 * @param: structure containing the new RT priority.
5232 * NOTE that the task may be already dead.
5234 int sched_setscheduler(struct task_struct *p, int policy,
5235 struct sched_param *param)
5237 return __sched_setscheduler(p, policy, param, true);
5239 EXPORT_SYMBOL_GPL(sched_setscheduler);
5242 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5243 * @p: the task in question.
5244 * @policy: new policy.
5245 * @param: structure containing the new RT priority.
5247 * Just like sched_setscheduler, only don't bother checking if the
5248 * current context has permission. For example, this is needed in
5249 * stop_machine(): we create temporary high priority worker threads,
5250 * but our caller might not have that capability.
5252 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
5253 struct sched_param *param)
5255 return __sched_setscheduler(p, policy, param, false);
5259 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5261 struct sched_param lparam;
5262 struct task_struct *p;
5265 if (!param || pid < 0)
5267 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
5272 p = find_process_by_pid(pid);
5274 retval = sched_setscheduler(p, policy, &lparam);
5281 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5282 * @pid: the pid in question.
5283 * @policy: new policy.
5284 * @param: structure containing the new RT priority.
5287 sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5289 /* negative values for policy are not valid */
5293 return do_sched_setscheduler(pid, policy, param);
5297 * sys_sched_setparam - set/change the RT priority of a thread
5298 * @pid: the pid in question.
5299 * @param: structure containing the new RT priority.
5301 asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
5303 return do_sched_setscheduler(pid, -1, param);
5307 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5308 * @pid: the pid in question.
5310 asmlinkage long sys_sched_getscheduler(pid_t pid)
5312 struct task_struct *p;
5319 read_lock(&tasklist_lock);
5320 p = find_process_by_pid(pid);
5322 retval = security_task_getscheduler(p);
5326 read_unlock(&tasklist_lock);
5331 * sys_sched_getscheduler - get the RT priority of a thread
5332 * @pid: the pid in question.
5333 * @param: structure containing the RT priority.
5335 asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param)
5337 struct sched_param lp;
5338 struct task_struct *p;
5341 if (!param || pid < 0)
5344 read_lock(&tasklist_lock);
5345 p = find_process_by_pid(pid);
5350 retval = security_task_getscheduler(p);
5354 lp.sched_priority = p->rt_priority;
5355 read_unlock(&tasklist_lock);
5358 * This one might sleep, we cannot do it with a spinlock held ...
5360 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
5365 read_unlock(&tasklist_lock);
5369 long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
5371 cpumask_t cpus_allowed;
5372 cpumask_t new_mask = *in_mask;
5373 struct task_struct *p;
5377 read_lock(&tasklist_lock);
5379 p = find_process_by_pid(pid);
5381 read_unlock(&tasklist_lock);
5387 * It is not safe to call set_cpus_allowed with the
5388 * tasklist_lock held. We will bump the task_struct's
5389 * usage count and then drop tasklist_lock.
5392 read_unlock(&tasklist_lock);
5395 if ((current->euid != p->euid) && (current->euid != p->uid) &&
5396 !capable(CAP_SYS_NICE))
5399 retval = security_task_setscheduler(p, 0, NULL);
5403 cpuset_cpus_allowed(p, &cpus_allowed);
5404 cpus_and(new_mask, new_mask, cpus_allowed);
5406 retval = set_cpus_allowed_ptr(p, &new_mask);
5409 cpuset_cpus_allowed(p, &cpus_allowed);
5410 if (!cpus_subset(new_mask, cpus_allowed)) {
5412 * We must have raced with a concurrent cpuset
5413 * update. Just reset the cpus_allowed to the
5414 * cpuset's cpus_allowed
5416 new_mask = cpus_allowed;
5426 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
5427 cpumask_t *new_mask)
5429 if (len < sizeof(cpumask_t)) {
5430 memset(new_mask, 0, sizeof(cpumask_t));
5431 } else if (len > sizeof(cpumask_t)) {
5432 len = sizeof(cpumask_t);
5434 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
5438 * sys_sched_setaffinity - set the cpu affinity of a process
5439 * @pid: pid of the process
5440 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5441 * @user_mask_ptr: user-space pointer to the new cpu mask
5443 asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
5444 unsigned long __user *user_mask_ptr)
5449 retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
5453 return sched_setaffinity(pid, &new_mask);
5456 long sched_getaffinity(pid_t pid, cpumask_t *mask)
5458 struct task_struct *p;
5462 read_lock(&tasklist_lock);
5465 p = find_process_by_pid(pid);
5469 retval = security_task_getscheduler(p);
5473 cpus_and(*mask, p->cpus_allowed, cpu_online_map);
5476 read_unlock(&tasklist_lock);
5483 * sys_sched_getaffinity - get the cpu affinity of a process
5484 * @pid: pid of the process
5485 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5486 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5488 asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
5489 unsigned long __user *user_mask_ptr)
5494 if (len < sizeof(cpumask_t))
5497 ret = sched_getaffinity(pid, &mask);
5501 if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t)))
5504 return sizeof(cpumask_t);
5508 * sys_sched_yield - yield the current processor to other threads.
5510 * This function yields the current CPU to other tasks. If there are no
5511 * other threads running on this CPU then this function will return.
5513 asmlinkage long sys_sched_yield(void)
5515 struct rq *rq = this_rq_lock();
5517 schedstat_inc(rq, yld_count);
5518 current->sched_class->yield_task(rq);
5521 * Since we are going to call schedule() anyway, there's
5522 * no need to preempt or enable interrupts:
5524 __release(rq->lock);
5525 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
5526 _raw_spin_unlock(&rq->lock);
5527 preempt_enable_no_resched();
5534 static void __cond_resched(void)
5536 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5537 __might_sleep(__FILE__, __LINE__);
5540 * The BKS might be reacquired before we have dropped
5541 * PREEMPT_ACTIVE, which could trigger a second
5542 * cond_resched() call.
5545 add_preempt_count(PREEMPT_ACTIVE);
5547 sub_preempt_count(PREEMPT_ACTIVE);
5548 } while (need_resched());
5551 int __sched _cond_resched(void)
5553 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
5554 system_state == SYSTEM_RUNNING) {
5560 EXPORT_SYMBOL(_cond_resched);
5563 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5564 * call schedule, and on return reacquire the lock.
5566 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5567 * operations here to prevent schedule() from being called twice (once via
5568 * spin_unlock(), once by hand).
5570 int cond_resched_lock(spinlock_t *lock)
5572 int resched = need_resched() && system_state == SYSTEM_RUNNING;
5575 if (spin_needbreak(lock) || resched) {
5577 if (resched && need_resched())
5586 EXPORT_SYMBOL(cond_resched_lock);
5588 int __sched cond_resched_softirq(void)
5590 BUG_ON(!in_softirq());
5592 if (need_resched() && system_state == SYSTEM_RUNNING) {
5600 EXPORT_SYMBOL(cond_resched_softirq);
5603 * yield - yield the current processor to other threads.
5605 * This is a shortcut for kernel-space yielding - it marks the
5606 * thread runnable and calls sys_sched_yield().
5608 void __sched yield(void)
5610 set_current_state(TASK_RUNNING);
5613 EXPORT_SYMBOL(yield);
5616 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5617 * that process accounting knows that this is a task in IO wait state.
5619 * But don't do that if it is a deliberate, throttling IO wait (this task
5620 * has set its backing_dev_info: the queue against which it should throttle)
5622 void __sched io_schedule(void)
5624 struct rq *rq = &__raw_get_cpu_var(runqueues);
5626 delayacct_blkio_start();
5627 atomic_inc(&rq->nr_iowait);
5629 atomic_dec(&rq->nr_iowait);
5630 delayacct_blkio_end();
5632 EXPORT_SYMBOL(io_schedule);
5634 long __sched io_schedule_timeout(long timeout)
5636 struct rq *rq = &__raw_get_cpu_var(runqueues);
5639 delayacct_blkio_start();
5640 atomic_inc(&rq->nr_iowait);
5641 ret = schedule_timeout(timeout);
5642 atomic_dec(&rq->nr_iowait);
5643 delayacct_blkio_end();
5648 * sys_sched_get_priority_max - return maximum RT priority.
5649 * @policy: scheduling class.
5651 * this syscall returns the maximum rt_priority that can be used
5652 * by a given scheduling class.
5654 asmlinkage long sys_sched_get_priority_max(int policy)
5661 ret = MAX_USER_RT_PRIO-1;
5673 * sys_sched_get_priority_min - return minimum RT priority.
5674 * @policy: scheduling class.
5676 * this syscall returns the minimum rt_priority that can be used
5677 * by a given scheduling class.
5679 asmlinkage long sys_sched_get_priority_min(int policy)
5697 * sys_sched_rr_get_interval - return the default timeslice of a process.
5698 * @pid: pid of the process.
5699 * @interval: userspace pointer to the timeslice value.
5701 * this syscall writes the default timeslice value of a given process
5702 * into the user-space timespec buffer. A value of '0' means infinity.
5705 long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
5707 struct task_struct *p;
5708 unsigned int time_slice;
5716 read_lock(&tasklist_lock);
5717 p = find_process_by_pid(pid);
5721 retval = security_task_getscheduler(p);
5726 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5727 * tasks that are on an otherwise idle runqueue:
5730 if (p->policy == SCHED_RR) {
5731 time_slice = DEF_TIMESLICE;
5732 } else if (p->policy != SCHED_FIFO) {
5733 struct sched_entity *se = &p->se;
5734 unsigned long flags;
5737 rq = task_rq_lock(p, &flags);
5738 if (rq->cfs.load.weight)
5739 time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
5740 task_rq_unlock(rq, &flags);
5742 read_unlock(&tasklist_lock);
5743 jiffies_to_timespec(time_slice, &t);
5744 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
5748 read_unlock(&tasklist_lock);
5752 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
5754 void sched_show_task(struct task_struct *p)
5756 unsigned long free = 0;
5759 state = p->state ? __ffs(p->state) + 1 : 0;
5760 printk(KERN_INFO "%-13.13s %c", p->comm,
5761 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
5762 #if BITS_PER_LONG == 32
5763 if (state == TASK_RUNNING)
5764 printk(KERN_CONT " running ");
5766 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
5768 if (state == TASK_RUNNING)
5769 printk(KERN_CONT " running task ");
5771 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
5773 #ifdef CONFIG_DEBUG_STACK_USAGE
5775 unsigned long *n = end_of_stack(p);
5778 free = (unsigned long)n - (unsigned long)end_of_stack(p);
5781 printk(KERN_CONT "%5lu %5d %6d\n", free,
5782 task_pid_nr(p), task_pid_nr(p->real_parent));
5784 show_stack(p, NULL);
5787 void show_state_filter(unsigned long state_filter)
5789 struct task_struct *g, *p;
5791 #if BITS_PER_LONG == 32
5793 " task PC stack pid father\n");
5796 " task PC stack pid father\n");
5798 read_lock(&tasklist_lock);
5799 do_each_thread(g, p) {
5801 * reset the NMI-timeout, listing all files on a slow
5802 * console might take alot of time:
5804 touch_nmi_watchdog();
5805 if (!state_filter || (p->state & state_filter))
5807 } while_each_thread(g, p);
5809 touch_all_softlockup_watchdogs();
5811 #ifdef CONFIG_SCHED_DEBUG
5812 sysrq_sched_debug_show();
5814 read_unlock(&tasklist_lock);
5816 * Only show locks if all tasks are dumped:
5818 if (state_filter == -1)
5819 debug_show_all_locks();
5822 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
5824 idle->sched_class = &idle_sched_class;
5828 * init_idle - set up an idle thread for a given CPU
5829 * @idle: task in question
5830 * @cpu: cpu the idle task belongs to
5832 * NOTE: this function does not set the idle thread's NEED_RESCHED
5833 * flag, to make booting more robust.
5835 void __cpuinit init_idle(struct task_struct *idle, int cpu)
5837 struct rq *rq = cpu_rq(cpu);
5838 unsigned long flags;
5840 spin_lock_irqsave(&rq->lock, flags);
5843 idle->se.exec_start = sched_clock();
5845 idle->prio = idle->normal_prio = MAX_PRIO;
5846 idle->cpus_allowed = cpumask_of_cpu(cpu);
5847 __set_task_cpu(idle, cpu);
5849 rq->curr = rq->idle = idle;
5850 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5853 spin_unlock_irqrestore(&rq->lock, flags);
5855 /* Set the preempt count _outside_ the spinlocks! */
5856 #if defined(CONFIG_PREEMPT)
5857 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
5859 task_thread_info(idle)->preempt_count = 0;
5862 * The idle tasks have their own, simple scheduling class:
5864 idle->sched_class = &idle_sched_class;
5865 ftrace_retfunc_init_task(idle);
5869 * In a system that switches off the HZ timer nohz_cpu_mask
5870 * indicates which cpus entered this state. This is used
5871 * in the rcu update to wait only for active cpus. For system
5872 * which do not switch off the HZ timer nohz_cpu_mask should
5873 * always be CPU_MASK_NONE.
5875 cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
5878 * Increase the granularity value when there are more CPUs,
5879 * because with more CPUs the 'effective latency' as visible
5880 * to users decreases. But the relationship is not linear,
5881 * so pick a second-best guess by going with the log2 of the
5884 * This idea comes from the SD scheduler of Con Kolivas:
5886 static inline void sched_init_granularity(void)
5888 unsigned int factor = 1 + ilog2(num_online_cpus());
5889 const unsigned long limit = 200000000;
5891 sysctl_sched_min_granularity *= factor;
5892 if (sysctl_sched_min_granularity > limit)
5893 sysctl_sched_min_granularity = limit;
5895 sysctl_sched_latency *= factor;
5896 if (sysctl_sched_latency > limit)
5897 sysctl_sched_latency = limit;
5899 sysctl_sched_wakeup_granularity *= factor;
5901 sysctl_sched_shares_ratelimit *= factor;
5906 * This is how migration works:
5908 * 1) we queue a struct migration_req structure in the source CPU's
5909 * runqueue and wake up that CPU's migration thread.
5910 * 2) we down() the locked semaphore => thread blocks.
5911 * 3) migration thread wakes up (implicitly it forces the migrated
5912 * thread off the CPU)
5913 * 4) it gets the migration request and checks whether the migrated
5914 * task is still in the wrong runqueue.
5915 * 5) if it's in the wrong runqueue then the migration thread removes
5916 * it and puts it into the right queue.
5917 * 6) migration thread up()s the semaphore.
5918 * 7) we wake up and the migration is done.
5922 * Change a given task's CPU affinity. Migrate the thread to a
5923 * proper CPU and schedule it away if the CPU it's executing on
5924 * is removed from the allowed bitmask.
5926 * NOTE: the caller must have a valid reference to the task, the
5927 * task must not exit() & deallocate itself prematurely. The
5928 * call is not atomic; no spinlocks may be held.
5930 int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask)
5932 struct migration_req req;
5933 unsigned long flags;
5937 rq = task_rq_lock(p, &flags);
5938 if (!cpus_intersects(*new_mask, cpu_online_map)) {
5943 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
5944 !cpus_equal(p->cpus_allowed, *new_mask))) {
5949 if (p->sched_class->set_cpus_allowed)
5950 p->sched_class->set_cpus_allowed(p, new_mask);
5952 p->cpus_allowed = *new_mask;
5953 p->rt.nr_cpus_allowed = cpus_weight(*new_mask);
5956 /* Can the task run on the task's current CPU? If so, we're done */
5957 if (cpu_isset(task_cpu(p), *new_mask))
5960 if (migrate_task(p, cpumask_any_and(cpu_online_mask, new_mask), &req)) {
5961 /* Need help from migration thread: drop lock and wait. */
5962 task_rq_unlock(rq, &flags);
5963 wake_up_process(rq->migration_thread);
5964 wait_for_completion(&req.done);
5965 tlb_migrate_finish(p->mm);
5969 task_rq_unlock(rq, &flags);
5973 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
5976 * Move (not current) task off this cpu, onto dest cpu. We're doing
5977 * this because either it can't run here any more (set_cpus_allowed()
5978 * away from this CPU, or CPU going down), or because we're
5979 * attempting to rebalance this task on exec (sched_exec).
5981 * So we race with normal scheduler movements, but that's OK, as long
5982 * as the task is no longer on this CPU.
5984 * Returns non-zero if task was successfully migrated.
5986 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
5988 struct rq *rq_dest, *rq_src;
5991 if (unlikely(!cpu_active(dest_cpu)))
5994 rq_src = cpu_rq(src_cpu);
5995 rq_dest = cpu_rq(dest_cpu);
5997 double_rq_lock(rq_src, rq_dest);
5998 /* Already moved. */
5999 if (task_cpu(p) != src_cpu)
6001 /* Affinity changed (again). */
6002 if (!cpu_isset(dest_cpu, p->cpus_allowed))
6005 on_rq = p->se.on_rq;
6007 deactivate_task(rq_src, p, 0);
6009 set_task_cpu(p, dest_cpu);
6011 activate_task(rq_dest, p, 0);
6012 check_preempt_curr(rq_dest, p, 0);
6017 double_rq_unlock(rq_src, rq_dest);
6022 * migration_thread - this is a highprio system thread that performs
6023 * thread migration by bumping thread off CPU then 'pushing' onto
6026 static int migration_thread(void *data)
6028 int cpu = (long)data;
6032 BUG_ON(rq->migration_thread != current);
6034 set_current_state(TASK_INTERRUPTIBLE);
6035 while (!kthread_should_stop()) {
6036 struct migration_req *req;
6037 struct list_head *head;
6039 spin_lock_irq(&rq->lock);
6041 if (cpu_is_offline(cpu)) {
6042 spin_unlock_irq(&rq->lock);
6046 if (rq->active_balance) {
6047 active_load_balance(rq, cpu);
6048 rq->active_balance = 0;
6051 head = &rq->migration_queue;
6053 if (list_empty(head)) {
6054 spin_unlock_irq(&rq->lock);
6056 set_current_state(TASK_INTERRUPTIBLE);
6059 req = list_entry(head->next, struct migration_req, list);
6060 list_del_init(head->next);
6062 spin_unlock(&rq->lock);
6063 __migrate_task(req->task, cpu, req->dest_cpu);
6066 complete(&req->done);
6068 __set_current_state(TASK_RUNNING);
6072 /* Wait for kthread_stop */
6073 set_current_state(TASK_INTERRUPTIBLE);
6074 while (!kthread_should_stop()) {
6076 set_current_state(TASK_INTERRUPTIBLE);
6078 __set_current_state(TASK_RUNNING);
6082 #ifdef CONFIG_HOTPLUG_CPU
6084 static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
6088 local_irq_disable();
6089 ret = __migrate_task(p, src_cpu, dest_cpu);
6095 * Figure out where task on dead CPU should go, use force if necessary.
6097 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
6099 unsigned long flags;
6106 node_to_cpumask_ptr(pnodemask, cpu_to_node(dead_cpu));
6108 cpus_and(mask, *pnodemask, p->cpus_allowed);
6109 dest_cpu = cpumask_any_and(cpu_online_mask, &mask);
6111 /* On any allowed CPU? */
6112 if (dest_cpu >= nr_cpu_ids)
6113 dest_cpu = cpumask_any_and(cpu_online_mask,
6116 /* No more Mr. Nice Guy. */
6117 if (dest_cpu >= nr_cpu_ids) {
6118 cpumask_t cpus_allowed;
6120 cpuset_cpus_allowed_locked(p, &cpus_allowed);
6122 * Try to stay on the same cpuset, where the
6123 * current cpuset may be a subset of all cpus.
6124 * The cpuset_cpus_allowed_locked() variant of
6125 * cpuset_cpus_allowed() will not block. It must be
6126 * called within calls to cpuset_lock/cpuset_unlock.
6128 rq = task_rq_lock(p, &flags);
6129 p->cpus_allowed = cpus_allowed;
6130 dest_cpu = cpumask_any_and(cpu_online_mask,
6132 task_rq_unlock(rq, &flags);
6135 * Don't tell them about moving exiting tasks or
6136 * kernel threads (both mm NULL), since they never
6139 if (p->mm && printk_ratelimit()) {
6140 printk(KERN_INFO "process %d (%s) no "
6141 "longer affine to cpu%d\n",
6142 task_pid_nr(p), p->comm, dead_cpu);
6145 } while (!__migrate_task_irq(p, dead_cpu, dest_cpu));
6149 * While a dead CPU has no uninterruptible tasks queued at this point,
6150 * it might still have a nonzero ->nr_uninterruptible counter, because
6151 * for performance reasons the counter is not stricly tracking tasks to
6152 * their home CPUs. So we just add the counter to another CPU's counter,
6153 * to keep the global sum constant after CPU-down:
6155 static void migrate_nr_uninterruptible(struct rq *rq_src)
6157 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_online_mask));
6158 unsigned long flags;
6160 local_irq_save(flags);
6161 double_rq_lock(rq_src, rq_dest);
6162 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
6163 rq_src->nr_uninterruptible = 0;
6164 double_rq_unlock(rq_src, rq_dest);
6165 local_irq_restore(flags);
6168 /* Run through task list and migrate tasks from the dead cpu. */
6169 static void migrate_live_tasks(int src_cpu)
6171 struct task_struct *p, *t;
6173 read_lock(&tasklist_lock);
6175 do_each_thread(t, p) {
6179 if (task_cpu(p) == src_cpu)
6180 move_task_off_dead_cpu(src_cpu, p);
6181 } while_each_thread(t, p);
6183 read_unlock(&tasklist_lock);
6187 * Schedules idle task to be the next runnable task on current CPU.
6188 * It does so by boosting its priority to highest possible.
6189 * Used by CPU offline code.
6191 void sched_idle_next(void)
6193 int this_cpu = smp_processor_id();
6194 struct rq *rq = cpu_rq(this_cpu);
6195 struct task_struct *p = rq->idle;
6196 unsigned long flags;
6198 /* cpu has to be offline */
6199 BUG_ON(cpu_online(this_cpu));
6202 * Strictly not necessary since rest of the CPUs are stopped by now
6203 * and interrupts disabled on the current cpu.
6205 spin_lock_irqsave(&rq->lock, flags);
6207 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6209 update_rq_clock(rq);
6210 activate_task(rq, p, 0);
6212 spin_unlock_irqrestore(&rq->lock, flags);
6216 * Ensures that the idle task is using init_mm right before its cpu goes
6219 void idle_task_exit(void)
6221 struct mm_struct *mm = current->active_mm;
6223 BUG_ON(cpu_online(smp_processor_id()));
6226 switch_mm(mm, &init_mm, current);
6230 /* called under rq->lock with disabled interrupts */
6231 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
6233 struct rq *rq = cpu_rq(dead_cpu);
6235 /* Must be exiting, otherwise would be on tasklist. */
6236 BUG_ON(!p->exit_state);
6238 /* Cannot have done final schedule yet: would have vanished. */
6239 BUG_ON(p->state == TASK_DEAD);
6244 * Drop lock around migration; if someone else moves it,
6245 * that's OK. No task can be added to this CPU, so iteration is
6248 spin_unlock_irq(&rq->lock);
6249 move_task_off_dead_cpu(dead_cpu, p);
6250 spin_lock_irq(&rq->lock);
6255 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6256 static void migrate_dead_tasks(unsigned int dead_cpu)
6258 struct rq *rq = cpu_rq(dead_cpu);
6259 struct task_struct *next;
6262 if (!rq->nr_running)
6264 update_rq_clock(rq);
6265 next = pick_next_task(rq, rq->curr);
6268 next->sched_class->put_prev_task(rq, next);
6269 migrate_dead(dead_cpu, next);
6273 #endif /* CONFIG_HOTPLUG_CPU */
6275 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6277 static struct ctl_table sd_ctl_dir[] = {
6279 .procname = "sched_domain",
6285 static struct ctl_table sd_ctl_root[] = {
6287 .ctl_name = CTL_KERN,
6288 .procname = "kernel",
6290 .child = sd_ctl_dir,
6295 static struct ctl_table *sd_alloc_ctl_entry(int n)
6297 struct ctl_table *entry =
6298 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
6303 static void sd_free_ctl_entry(struct ctl_table **tablep)
6305 struct ctl_table *entry;
6308 * In the intermediate directories, both the child directory and
6309 * procname are dynamically allocated and could fail but the mode
6310 * will always be set. In the lowest directory the names are
6311 * static strings and all have proc handlers.
6313 for (entry = *tablep; entry->mode; entry++) {
6315 sd_free_ctl_entry(&entry->child);
6316 if (entry->proc_handler == NULL)
6317 kfree(entry->procname);
6325 set_table_entry(struct ctl_table *entry,
6326 const char *procname, void *data, int maxlen,
6327 mode_t mode, proc_handler *proc_handler)
6329 entry->procname = procname;
6331 entry->maxlen = maxlen;
6333 entry->proc_handler = proc_handler;
6336 static struct ctl_table *
6337 sd_alloc_ctl_domain_table(struct sched_domain *sd)
6339 struct ctl_table *table = sd_alloc_ctl_entry(13);
6344 set_table_entry(&table[0], "min_interval", &sd->min_interval,
6345 sizeof(long), 0644, proc_doulongvec_minmax);
6346 set_table_entry(&table[1], "max_interval", &sd->max_interval,
6347 sizeof(long), 0644, proc_doulongvec_minmax);
6348 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
6349 sizeof(int), 0644, proc_dointvec_minmax);
6350 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
6351 sizeof(int), 0644, proc_dointvec_minmax);
6352 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
6353 sizeof(int), 0644, proc_dointvec_minmax);
6354 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
6355 sizeof(int), 0644, proc_dointvec_minmax);
6356 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
6357 sizeof(int), 0644, proc_dointvec_minmax);
6358 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
6359 sizeof(int), 0644, proc_dointvec_minmax);
6360 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
6361 sizeof(int), 0644, proc_dointvec_minmax);
6362 set_table_entry(&table[9], "cache_nice_tries",
6363 &sd->cache_nice_tries,
6364 sizeof(int), 0644, proc_dointvec_minmax);
6365 set_table_entry(&table[10], "flags", &sd->flags,
6366 sizeof(int), 0644, proc_dointvec_minmax);
6367 set_table_entry(&table[11], "name", sd->name,
6368 CORENAME_MAX_SIZE, 0444, proc_dostring);
6369 /* &table[12] is terminator */
6374 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
6376 struct ctl_table *entry, *table;
6377 struct sched_domain *sd;
6378 int domain_num = 0, i;
6381 for_each_domain(cpu, sd)
6383 entry = table = sd_alloc_ctl_entry(domain_num + 1);
6388 for_each_domain(cpu, sd) {
6389 snprintf(buf, 32, "domain%d", i);
6390 entry->procname = kstrdup(buf, GFP_KERNEL);
6392 entry->child = sd_alloc_ctl_domain_table(sd);
6399 static struct ctl_table_header *sd_sysctl_header;
6400 static void register_sched_domain_sysctl(void)
6402 int i, cpu_num = num_online_cpus();
6403 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
6406 WARN_ON(sd_ctl_dir[0].child);
6407 sd_ctl_dir[0].child = entry;
6412 for_each_online_cpu(i) {
6413 snprintf(buf, 32, "cpu%d", i);
6414 entry->procname = kstrdup(buf, GFP_KERNEL);
6416 entry->child = sd_alloc_ctl_cpu_table(i);
6420 WARN_ON(sd_sysctl_header);
6421 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
6424 /* may be called multiple times per register */
6425 static void unregister_sched_domain_sysctl(void)
6427 if (sd_sysctl_header)
6428 unregister_sysctl_table(sd_sysctl_header);
6429 sd_sysctl_header = NULL;
6430 if (sd_ctl_dir[0].child)
6431 sd_free_ctl_entry(&sd_ctl_dir[0].child);
6434 static void register_sched_domain_sysctl(void)
6437 static void unregister_sched_domain_sysctl(void)
6442 static void set_rq_online(struct rq *rq)
6445 const struct sched_class *class;
6447 cpu_set(rq->cpu, rq->rd->online);
6450 for_each_class(class) {
6451 if (class->rq_online)
6452 class->rq_online(rq);
6457 static void set_rq_offline(struct rq *rq)
6460 const struct sched_class *class;
6462 for_each_class(class) {
6463 if (class->rq_offline)
6464 class->rq_offline(rq);
6467 cpu_clear(rq->cpu, rq->rd->online);
6473 * migration_call - callback that gets triggered when a CPU is added.
6474 * Here we can start up the necessary migration thread for the new CPU.
6476 static int __cpuinit
6477 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
6479 struct task_struct *p;
6480 int cpu = (long)hcpu;
6481 unsigned long flags;
6486 case CPU_UP_PREPARE:
6487 case CPU_UP_PREPARE_FROZEN:
6488 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
6491 kthread_bind(p, cpu);
6492 /* Must be high prio: stop_machine expects to yield to it. */
6493 rq = task_rq_lock(p, &flags);
6494 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6495 task_rq_unlock(rq, &flags);
6496 cpu_rq(cpu)->migration_thread = p;
6500 case CPU_ONLINE_FROZEN:
6501 /* Strictly unnecessary, as first user will wake it. */
6502 wake_up_process(cpu_rq(cpu)->migration_thread);
6504 /* Update our root-domain */
6506 spin_lock_irqsave(&rq->lock, flags);
6508 BUG_ON(!cpu_isset(cpu, rq->rd->span));
6512 spin_unlock_irqrestore(&rq->lock, flags);
6515 #ifdef CONFIG_HOTPLUG_CPU
6516 case CPU_UP_CANCELED:
6517 case CPU_UP_CANCELED_FROZEN:
6518 if (!cpu_rq(cpu)->migration_thread)
6520 /* Unbind it from offline cpu so it can run. Fall thru. */
6521 kthread_bind(cpu_rq(cpu)->migration_thread,
6522 cpumask_any(cpu_online_mask));
6523 kthread_stop(cpu_rq(cpu)->migration_thread);
6524 cpu_rq(cpu)->migration_thread = NULL;
6528 case CPU_DEAD_FROZEN:
6529 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6530 migrate_live_tasks(cpu);
6532 kthread_stop(rq->migration_thread);
6533 rq->migration_thread = NULL;
6534 /* Idle task back to normal (off runqueue, low prio) */
6535 spin_lock_irq(&rq->lock);
6536 update_rq_clock(rq);
6537 deactivate_task(rq, rq->idle, 0);
6538 rq->idle->static_prio = MAX_PRIO;
6539 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
6540 rq->idle->sched_class = &idle_sched_class;
6541 migrate_dead_tasks(cpu);
6542 spin_unlock_irq(&rq->lock);
6544 migrate_nr_uninterruptible(rq);
6545 BUG_ON(rq->nr_running != 0);
6548 * No need to migrate the tasks: it was best-effort if
6549 * they didn't take sched_hotcpu_mutex. Just wake up
6552 spin_lock_irq(&rq->lock);
6553 while (!list_empty(&rq->migration_queue)) {
6554 struct migration_req *req;
6556 req = list_entry(rq->migration_queue.next,
6557 struct migration_req, list);
6558 list_del_init(&req->list);
6559 complete(&req->done);
6561 spin_unlock_irq(&rq->lock);
6565 case CPU_DYING_FROZEN:
6566 /* Update our root-domain */
6568 spin_lock_irqsave(&rq->lock, flags);
6570 BUG_ON(!cpu_isset(cpu, rq->rd->span));
6573 spin_unlock_irqrestore(&rq->lock, flags);
6580 /* Register at highest priority so that task migration (migrate_all_tasks)
6581 * happens before everything else.
6583 static struct notifier_block __cpuinitdata migration_notifier = {
6584 .notifier_call = migration_call,
6588 static int __init migration_init(void)
6590 void *cpu = (void *)(long)smp_processor_id();
6593 /* Start one for the boot CPU: */
6594 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
6595 BUG_ON(err == NOTIFY_BAD);
6596 migration_call(&migration_notifier, CPU_ONLINE, cpu);
6597 register_cpu_notifier(&migration_notifier);
6601 early_initcall(migration_init);
6606 #ifdef CONFIG_SCHED_DEBUG
6608 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
6609 cpumask_t *groupmask)
6611 struct sched_group *group = sd->groups;
6614 cpulist_scnprintf(str, sizeof(str), *sched_domain_span(sd));
6615 cpus_clear(*groupmask);
6617 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
6619 if (!(sd->flags & SD_LOAD_BALANCE)) {
6620 printk("does not load-balance\n");
6622 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
6627 printk(KERN_CONT "span %s level %s\n", str, sd->name);
6629 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
6630 printk(KERN_ERR "ERROR: domain->span does not contain "
6633 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
6634 printk(KERN_ERR "ERROR: domain->groups does not contain"
6638 printk(KERN_DEBUG "%*s groups:", level + 1, "");
6642 printk(KERN_ERR "ERROR: group is NULL\n");
6646 if (!group->__cpu_power) {
6647 printk(KERN_CONT "\n");
6648 printk(KERN_ERR "ERROR: domain->cpu_power not "
6653 if (!cpumask_weight(sched_group_cpus(group))) {
6654 printk(KERN_CONT "\n");
6655 printk(KERN_ERR "ERROR: empty group\n");
6659 if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
6660 printk(KERN_CONT "\n");
6661 printk(KERN_ERR "ERROR: repeated CPUs\n");
6665 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
6667 cpulist_scnprintf(str, sizeof(str), *sched_group_cpus(group));
6668 printk(KERN_CONT " %s", str);
6670 group = group->next;
6671 } while (group != sd->groups);
6672 printk(KERN_CONT "\n");
6674 if (!cpumask_equal(sched_domain_span(sd), groupmask))
6675 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
6678 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
6679 printk(KERN_ERR "ERROR: parent span is not a superset "
6680 "of domain->span\n");
6684 static void sched_domain_debug(struct sched_domain *sd, int cpu)
6686 cpumask_t *groupmask;
6690 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
6694 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
6696 groupmask = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
6698 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
6703 if (sched_domain_debug_one(sd, cpu, level, groupmask))
6712 #else /* !CONFIG_SCHED_DEBUG */
6713 # define sched_domain_debug(sd, cpu) do { } while (0)
6714 #endif /* CONFIG_SCHED_DEBUG */
6716 static int sd_degenerate(struct sched_domain *sd)
6718 if (cpumask_weight(sched_domain_span(sd)) == 1)
6721 /* Following flags need at least 2 groups */
6722 if (sd->flags & (SD_LOAD_BALANCE |
6723 SD_BALANCE_NEWIDLE |
6727 SD_SHARE_PKG_RESOURCES)) {
6728 if (sd->groups != sd->groups->next)
6732 /* Following flags don't use groups */
6733 if (sd->flags & (SD_WAKE_IDLE |
6742 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
6744 unsigned long cflags = sd->flags, pflags = parent->flags;
6746 if (sd_degenerate(parent))
6749 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
6752 /* Does parent contain flags not in child? */
6753 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6754 if (cflags & SD_WAKE_AFFINE)
6755 pflags &= ~SD_WAKE_BALANCE;
6756 /* Flags needing groups don't count if only 1 group in parent */
6757 if (parent->groups == parent->groups->next) {
6758 pflags &= ~(SD_LOAD_BALANCE |
6759 SD_BALANCE_NEWIDLE |
6763 SD_SHARE_PKG_RESOURCES);
6765 if (~cflags & pflags)
6771 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
6773 unsigned long flags;
6775 spin_lock_irqsave(&rq->lock, flags);
6778 struct root_domain *old_rd = rq->rd;
6780 if (cpu_isset(rq->cpu, old_rd->online))
6783 cpu_clear(rq->cpu, old_rd->span);
6785 if (atomic_dec_and_test(&old_rd->refcount))
6789 atomic_inc(&rd->refcount);
6792 cpu_set(rq->cpu, rd->span);
6793 if (cpu_isset(rq->cpu, cpu_online_map))
6796 spin_unlock_irqrestore(&rq->lock, flags);
6799 static void init_rootdomain(struct root_domain *rd)
6801 memset(rd, 0, sizeof(*rd));
6803 cpus_clear(rd->span);
6804 cpus_clear(rd->online);
6806 cpupri_init(&rd->cpupri);
6809 static void init_defrootdomain(void)
6811 init_rootdomain(&def_root_domain);
6812 atomic_set(&def_root_domain.refcount, 1);
6815 static struct root_domain *alloc_rootdomain(void)
6817 struct root_domain *rd;
6819 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
6823 init_rootdomain(rd);
6829 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6830 * hold the hotplug lock.
6833 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
6835 struct rq *rq = cpu_rq(cpu);
6836 struct sched_domain *tmp;
6838 /* Remove the sched domains which do not contribute to scheduling. */
6839 for (tmp = sd; tmp; ) {
6840 struct sched_domain *parent = tmp->parent;
6844 if (sd_parent_degenerate(tmp, parent)) {
6845 tmp->parent = parent->parent;
6847 parent->parent->child = tmp;
6852 if (sd && sd_degenerate(sd)) {
6858 sched_domain_debug(sd, cpu);
6860 rq_attach_root(rq, rd);
6861 rcu_assign_pointer(rq->sd, sd);
6864 /* cpus with isolated domains */
6865 static cpumask_t cpu_isolated_map = CPU_MASK_NONE;
6867 /* Setup the mask of cpus configured for isolated domains */
6868 static int __init isolated_cpu_setup(char *str)
6870 static int __initdata ints[NR_CPUS];
6873 str = get_options(str, ARRAY_SIZE(ints), ints);
6874 cpus_clear(cpu_isolated_map);
6875 for (i = 1; i <= ints[0]; i++)
6876 if (ints[i] < NR_CPUS)
6877 cpu_set(ints[i], cpu_isolated_map);
6881 __setup("isolcpus=", isolated_cpu_setup);
6884 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6885 * to a function which identifies what group(along with sched group) a CPU
6886 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6887 * (due to the fact that we keep track of groups covered with a cpumask_t).
6889 * init_sched_build_groups will build a circular linked list of the groups
6890 * covered by the given span, and will set each group's ->cpumask correctly,
6891 * and ->cpu_power to 0.
6894 init_sched_build_groups(const cpumask_t *span, const cpumask_t *cpu_map,
6895 int (*group_fn)(int cpu, const cpumask_t *cpu_map,
6896 struct sched_group **sg,
6897 cpumask_t *tmpmask),
6898 cpumask_t *covered, cpumask_t *tmpmask)
6900 struct sched_group *first = NULL, *last = NULL;
6903 cpus_clear(*covered);
6905 for_each_cpu(i, span) {
6906 struct sched_group *sg;
6907 int group = group_fn(i, cpu_map, &sg, tmpmask);
6910 if (cpumask_test_cpu(i, covered))
6913 cpumask_clear(sched_group_cpus(sg));
6914 sg->__cpu_power = 0;
6916 for_each_cpu(j, span) {
6917 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
6920 cpu_set(j, *covered);
6921 cpumask_set_cpu(j, sched_group_cpus(sg));
6932 #define SD_NODES_PER_DOMAIN 16
6937 * find_next_best_node - find the next node to include in a sched_domain
6938 * @node: node whose sched_domain we're building
6939 * @used_nodes: nodes already in the sched_domain
6941 * Find the next node to include in a given scheduling domain. Simply
6942 * finds the closest node not already in the @used_nodes map.
6944 * Should use nodemask_t.
6946 static int find_next_best_node(int node, nodemask_t *used_nodes)
6948 int i, n, val, min_val, best_node = 0;
6952 for (i = 0; i < nr_node_ids; i++) {
6953 /* Start at @node */
6954 n = (node + i) % nr_node_ids;
6956 if (!nr_cpus_node(n))
6959 /* Skip already used nodes */
6960 if (node_isset(n, *used_nodes))
6963 /* Simple min distance search */
6964 val = node_distance(node, n);
6966 if (val < min_val) {
6972 node_set(best_node, *used_nodes);
6977 * sched_domain_node_span - get a cpumask for a node's sched_domain
6978 * @node: node whose cpumask we're constructing
6979 * @span: resulting cpumask
6981 * Given a node, construct a good cpumask for its sched_domain to span. It
6982 * should be one that prevents unnecessary balancing, but also spreads tasks
6985 static void sched_domain_node_span(int node, cpumask_t *span)
6987 nodemask_t used_nodes;
6988 node_to_cpumask_ptr(nodemask, node);
6992 nodes_clear(used_nodes);
6994 cpus_or(*span, *span, *nodemask);
6995 node_set(node, used_nodes);
6997 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
6998 int next_node = find_next_best_node(node, &used_nodes);
7000 node_to_cpumask_ptr_next(nodemask, next_node);
7001 cpus_or(*span, *span, *nodemask);
7004 #endif /* CONFIG_NUMA */
7006 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
7009 * The cpus mask in sched_group and sched_domain hangs off the end.
7010 * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
7011 * for nr_cpu_ids < CONFIG_NR_CPUS.
7013 struct static_sched_group {
7014 struct sched_group sg;
7015 DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
7018 struct static_sched_domain {
7019 struct sched_domain sd;
7020 DECLARE_BITMAP(span, CONFIG_NR_CPUS);
7024 * SMT sched-domains:
7026 #ifdef CONFIG_SCHED_SMT
7027 static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
7028 static DEFINE_PER_CPU(struct static_sched_group, sched_group_cpus);
7031 cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
7035 *sg = &per_cpu(sched_group_cpus, cpu).sg;
7038 #endif /* CONFIG_SCHED_SMT */
7041 * multi-core sched-domains:
7043 #ifdef CONFIG_SCHED_MC
7044 static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
7045 static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
7046 #endif /* CONFIG_SCHED_MC */
7048 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7050 cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
7055 *mask = per_cpu(cpu_sibling_map, cpu);
7056 cpus_and(*mask, *mask, *cpu_map);
7057 group = first_cpu(*mask);
7059 *sg = &per_cpu(sched_group_core, group).sg;
7062 #elif defined(CONFIG_SCHED_MC)
7064 cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
7068 *sg = &per_cpu(sched_group_core, cpu).sg;
7073 static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
7074 static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
7077 cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
7081 #ifdef CONFIG_SCHED_MC
7082 *mask = cpu_coregroup_map(cpu);
7083 cpus_and(*mask, *mask, *cpu_map);
7084 group = first_cpu(*mask);
7085 #elif defined(CONFIG_SCHED_SMT)
7086 *mask = per_cpu(cpu_sibling_map, cpu);
7087 cpus_and(*mask, *mask, *cpu_map);
7088 group = first_cpu(*mask);
7093 *sg = &per_cpu(sched_group_phys, group).sg;
7099 * The init_sched_build_groups can't handle what we want to do with node
7100 * groups, so roll our own. Now each node has its own list of groups which
7101 * gets dynamically allocated.
7103 static DEFINE_PER_CPU(struct sched_domain, node_domains);
7104 static struct sched_group ***sched_group_nodes_bycpu;
7106 static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
7107 static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
7109 static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map,
7110 struct sched_group **sg, cpumask_t *nodemask)
7113 node_to_cpumask_ptr(pnodemask, cpu_to_node(cpu));
7115 cpus_and(*nodemask, *pnodemask, *cpu_map);
7116 group = first_cpu(*nodemask);
7119 *sg = &per_cpu(sched_group_allnodes, group).sg;
7123 static void init_numa_sched_groups_power(struct sched_group *group_head)
7125 struct sched_group *sg = group_head;
7131 for_each_cpu(j, sched_group_cpus(sg)) {
7132 struct sched_domain *sd;
7134 sd = &per_cpu(phys_domains, j).sd;
7135 if (j != cpumask_first(sched_group_cpus(sd->groups))) {
7137 * Only add "power" once for each
7143 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
7146 } while (sg != group_head);
7148 #endif /* CONFIG_NUMA */
7151 /* Free memory allocated for various sched_group structures */
7152 static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
7156 for_each_cpu(cpu, cpu_map) {
7157 struct sched_group **sched_group_nodes
7158 = sched_group_nodes_bycpu[cpu];
7160 if (!sched_group_nodes)
7163 for (i = 0; i < nr_node_ids; i++) {
7164 struct sched_group *oldsg, *sg = sched_group_nodes[i];
7165 node_to_cpumask_ptr(pnodemask, i);
7167 cpus_and(*nodemask, *pnodemask, *cpu_map);
7168 if (cpus_empty(*nodemask))
7178 if (oldsg != sched_group_nodes[i])
7181 kfree(sched_group_nodes);
7182 sched_group_nodes_bycpu[cpu] = NULL;
7185 #else /* !CONFIG_NUMA */
7186 static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
7189 #endif /* CONFIG_NUMA */
7192 * Initialize sched groups cpu_power.
7194 * cpu_power indicates the capacity of sched group, which is used while
7195 * distributing the load between different sched groups in a sched domain.
7196 * Typically cpu_power for all the groups in a sched domain will be same unless
7197 * there are asymmetries in the topology. If there are asymmetries, group
7198 * having more cpu_power will pickup more load compared to the group having
7201 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7202 * the maximum number of tasks a group can handle in the presence of other idle
7203 * or lightly loaded groups in the same sched domain.
7205 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
7207 struct sched_domain *child;
7208 struct sched_group *group;
7210 WARN_ON(!sd || !sd->groups);
7212 if (cpu != cpumask_first(sched_group_cpus(sd->groups)))
7217 sd->groups->__cpu_power = 0;
7220 * For perf policy, if the groups in child domain share resources
7221 * (for example cores sharing some portions of the cache hierarchy
7222 * or SMT), then set this domain groups cpu_power such that each group
7223 * can handle only one task, when there are other idle groups in the
7224 * same sched domain.
7226 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
7228 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
7229 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
7234 * add cpu_power of each child group to this groups cpu_power
7236 group = child->groups;
7238 sg_inc_cpu_power(sd->groups, group->__cpu_power);
7239 group = group->next;
7240 } while (group != child->groups);
7244 * Initializers for schedule domains
7245 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7248 #ifdef CONFIG_SCHED_DEBUG
7249 # define SD_INIT_NAME(sd, type) sd->name = #type
7251 # define SD_INIT_NAME(sd, type) do { } while (0)
7254 #define SD_INIT(sd, type) sd_init_##type(sd)
7256 #define SD_INIT_FUNC(type) \
7257 static noinline void sd_init_##type(struct sched_domain *sd) \
7259 memset(sd, 0, sizeof(*sd)); \
7260 *sd = SD_##type##_INIT; \
7261 sd->level = SD_LV_##type; \
7262 SD_INIT_NAME(sd, type); \
7267 SD_INIT_FUNC(ALLNODES)
7270 #ifdef CONFIG_SCHED_SMT
7271 SD_INIT_FUNC(SIBLING)
7273 #ifdef CONFIG_SCHED_MC
7277 static int default_relax_domain_level = -1;
7279 static int __init setup_relax_domain_level(char *str)
7283 val = simple_strtoul(str, NULL, 0);
7284 if (val < SD_LV_MAX)
7285 default_relax_domain_level = val;
7289 __setup("relax_domain_level=", setup_relax_domain_level);
7291 static void set_domain_attribute(struct sched_domain *sd,
7292 struct sched_domain_attr *attr)
7296 if (!attr || attr->relax_domain_level < 0) {
7297 if (default_relax_domain_level < 0)
7300 request = default_relax_domain_level;
7302 request = attr->relax_domain_level;
7303 if (request < sd->level) {
7304 /* turn off idle balance on this domain */
7305 sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
7307 /* turn on idle balance on this domain */
7308 sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
7313 * Build sched domains for a given set of cpus and attach the sched domains
7314 * to the individual cpus
7316 static int __build_sched_domains(const cpumask_t *cpu_map,
7317 struct sched_domain_attr *attr)
7319 int i, err = -ENOMEM;
7320 struct root_domain *rd;
7321 cpumask_var_t nodemask, this_sibling_map, this_core_map, send_covered,
7324 cpumask_var_t domainspan, covered, notcovered;
7325 struct sched_group **sched_group_nodes = NULL;
7326 int sd_allnodes = 0;
7328 if (!alloc_cpumask_var(&domainspan, GFP_KERNEL))
7330 if (!alloc_cpumask_var(&covered, GFP_KERNEL))
7331 goto free_domainspan;
7332 if (!alloc_cpumask_var(¬covered, GFP_KERNEL))
7336 if (!alloc_cpumask_var(&nodemask, GFP_KERNEL))
7337 goto free_notcovered;
7338 if (!alloc_cpumask_var(&this_sibling_map, GFP_KERNEL))
7340 if (!alloc_cpumask_var(&this_core_map, GFP_KERNEL))
7341 goto free_this_sibling_map;
7342 if (!alloc_cpumask_var(&send_covered, GFP_KERNEL))
7343 goto free_this_core_map;
7344 if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
7345 goto free_send_covered;
7349 * Allocate the per-node list of sched groups
7351 sched_group_nodes = kcalloc(nr_node_ids, sizeof(struct sched_group *),
7353 if (!sched_group_nodes) {
7354 printk(KERN_WARNING "Can not alloc sched group node list\n");
7359 rd = alloc_rootdomain();
7361 printk(KERN_WARNING "Cannot alloc root domain\n");
7362 goto free_sched_groups;
7366 sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
7370 * Set up domains for cpus specified by the cpu_map.
7372 for_each_cpu(i, cpu_map) {
7373 struct sched_domain *sd = NULL, *p;
7375 *nodemask = node_to_cpumask(cpu_to_node(i));
7376 cpus_and(*nodemask, *nodemask, *cpu_map);
7379 if (cpus_weight(*cpu_map) >
7380 SD_NODES_PER_DOMAIN*cpus_weight(*nodemask)) {
7381 sd = &per_cpu(allnodes_domains, i);
7382 SD_INIT(sd, ALLNODES);
7383 set_domain_attribute(sd, attr);
7384 cpumask_copy(sched_domain_span(sd), cpu_map);
7385 cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
7391 sd = &per_cpu(node_domains, i);
7393 set_domain_attribute(sd, attr);
7394 sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd));
7398 cpumask_and(sched_domain_span(sd),
7399 sched_domain_span(sd), cpu_map);
7403 sd = &per_cpu(phys_domains, i).sd;
7405 set_domain_attribute(sd, attr);
7406 cpumask_copy(sched_domain_span(sd), nodemask);
7410 cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
7412 #ifdef CONFIG_SCHED_MC
7414 sd = &per_cpu(core_domains, i).sd;
7416 set_domain_attribute(sd, attr);
7417 *sched_domain_span(sd) = cpu_coregroup_map(i);
7418 cpumask_and(sched_domain_span(sd),
7419 sched_domain_span(sd), cpu_map);
7422 cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
7425 #ifdef CONFIG_SCHED_SMT
7427 sd = &per_cpu(cpu_domains, i).sd;
7428 SD_INIT(sd, SIBLING);
7429 set_domain_attribute(sd, attr);
7430 cpumask_and(sched_domain_span(sd),
7431 &per_cpu(cpu_sibling_map, i), cpu_map);
7434 cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
7438 #ifdef CONFIG_SCHED_SMT
7439 /* Set up CPU (sibling) groups */
7440 for_each_cpu(i, cpu_map) {
7441 *this_sibling_map = per_cpu(cpu_sibling_map, i);
7442 cpus_and(*this_sibling_map, *this_sibling_map, *cpu_map);
7443 if (i != first_cpu(*this_sibling_map))
7446 init_sched_build_groups(this_sibling_map, cpu_map,
7448 send_covered, tmpmask);
7452 #ifdef CONFIG_SCHED_MC
7453 /* Set up multi-core groups */
7454 for_each_cpu(i, cpu_map) {
7455 *this_core_map = cpu_coregroup_map(i);
7456 cpus_and(*this_core_map, *this_core_map, *cpu_map);
7457 if (i != first_cpu(*this_core_map))
7460 init_sched_build_groups(this_core_map, cpu_map,
7462 send_covered, tmpmask);
7466 /* Set up physical groups */
7467 for (i = 0; i < nr_node_ids; i++) {
7468 *nodemask = node_to_cpumask(i);
7469 cpus_and(*nodemask, *nodemask, *cpu_map);
7470 if (cpus_empty(*nodemask))
7473 init_sched_build_groups(nodemask, cpu_map,
7475 send_covered, tmpmask);
7479 /* Set up node groups */
7481 init_sched_build_groups(cpu_map, cpu_map,
7482 &cpu_to_allnodes_group,
7483 send_covered, tmpmask);
7486 for (i = 0; i < nr_node_ids; i++) {
7487 /* Set up node groups */
7488 struct sched_group *sg, *prev;
7491 *nodemask = node_to_cpumask(i);
7492 cpus_clear(*covered);
7494 cpus_and(*nodemask, *nodemask, *cpu_map);
7495 if (cpus_empty(*nodemask)) {
7496 sched_group_nodes[i] = NULL;
7500 sched_domain_node_span(i, domainspan);
7501 cpus_and(*domainspan, *domainspan, *cpu_map);
7503 sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
7506 printk(KERN_WARNING "Can not alloc domain group for "
7510 sched_group_nodes[i] = sg;
7511 for_each_cpu(j, nodemask) {
7512 struct sched_domain *sd;
7514 sd = &per_cpu(node_domains, j);
7517 sg->__cpu_power = 0;
7518 cpumask_copy(sched_group_cpus(sg), nodemask);
7520 cpus_or(*covered, *covered, *nodemask);
7523 for (j = 0; j < nr_node_ids; j++) {
7524 int n = (i + j) % nr_node_ids;
7525 node_to_cpumask_ptr(pnodemask, n);
7527 cpus_complement(*notcovered, *covered);
7528 cpus_and(*tmpmask, *notcovered, *cpu_map);
7529 cpus_and(*tmpmask, *tmpmask, *domainspan);
7530 if (cpus_empty(*tmpmask))
7533 cpus_and(*tmpmask, *tmpmask, *pnodemask);
7534 if (cpus_empty(*tmpmask))
7537 sg = kmalloc_node(sizeof(struct sched_group) +
7542 "Can not alloc domain group for node %d\n", j);
7545 sg->__cpu_power = 0;
7546 cpumask_copy(sched_group_cpus(sg), tmpmask);
7547 sg->next = prev->next;
7548 cpus_or(*covered, *covered, *tmpmask);
7555 /* Calculate CPU power for physical packages and nodes */
7556 #ifdef CONFIG_SCHED_SMT
7557 for_each_cpu(i, cpu_map) {
7558 struct sched_domain *sd = &per_cpu(cpu_domains, i).sd;
7560 init_sched_groups_power(i, sd);
7563 #ifdef CONFIG_SCHED_MC
7564 for_each_cpu(i, cpu_map) {
7565 struct sched_domain *sd = &per_cpu(core_domains, i).sd;
7567 init_sched_groups_power(i, sd);
7571 for_each_cpu(i, cpu_map) {
7572 struct sched_domain *sd = &per_cpu(phys_domains, i).sd;
7574 init_sched_groups_power(i, sd);
7578 for (i = 0; i < nr_node_ids; i++)
7579 init_numa_sched_groups_power(sched_group_nodes[i]);
7582 struct sched_group *sg;
7584 cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg,
7586 init_numa_sched_groups_power(sg);
7590 /* Attach the domains */
7591 for_each_cpu(i, cpu_map) {
7592 struct sched_domain *sd;
7593 #ifdef CONFIG_SCHED_SMT
7594 sd = &per_cpu(cpu_domains, i).sd;
7595 #elif defined(CONFIG_SCHED_MC)
7596 sd = &per_cpu(core_domains, i).sd;
7598 sd = &per_cpu(phys_domains, i).sd;
7600 cpu_attach_domain(sd, rd, i);
7606 free_cpumask_var(tmpmask);
7608 free_cpumask_var(send_covered);
7610 free_cpumask_var(this_core_map);
7611 free_this_sibling_map:
7612 free_cpumask_var(this_sibling_map);
7614 free_cpumask_var(nodemask);
7617 free_cpumask_var(notcovered);
7619 free_cpumask_var(covered);
7621 free_cpumask_var(domainspan);
7628 kfree(sched_group_nodes);
7634 free_sched_groups(cpu_map, tmpmask);
7640 static int build_sched_domains(const cpumask_t *cpu_map)
7642 return __build_sched_domains(cpu_map, NULL);
7645 static cpumask_t *doms_cur; /* current sched domains */
7646 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
7647 static struct sched_domain_attr *dattr_cur;
7648 /* attribues of custom domains in 'doms_cur' */
7651 * Special case: If a kmalloc of a doms_cur partition (array of
7652 * cpumask_t) fails, then fallback to a single sched domain,
7653 * as determined by the single cpumask_t fallback_doms.
7655 static cpumask_t fallback_doms;
7657 void __attribute__((weak)) arch_update_cpu_topology(void)
7662 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7663 * For now this just excludes isolated cpus, but could be used to
7664 * exclude other special cases in the future.
7666 static int arch_init_sched_domains(const cpumask_t *cpu_map)
7670 arch_update_cpu_topology();
7672 doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
7674 doms_cur = &fallback_doms;
7675 cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map);
7677 err = build_sched_domains(doms_cur);
7678 register_sched_domain_sysctl();
7683 static void arch_destroy_sched_domains(const cpumask_t *cpu_map,
7686 free_sched_groups(cpu_map, tmpmask);
7690 * Detach sched domains from a group of cpus specified in cpu_map
7691 * These cpus will now be attached to the NULL domain
7693 static void detach_destroy_domains(const cpumask_t *cpu_map)
7698 for_each_cpu(i, cpu_map)
7699 cpu_attach_domain(NULL, &def_root_domain, i);
7700 synchronize_sched();
7701 arch_destroy_sched_domains(cpu_map, &tmpmask);
7704 /* handle null as "default" */
7705 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
7706 struct sched_domain_attr *new, int idx_new)
7708 struct sched_domain_attr tmp;
7715 return !memcmp(cur ? (cur + idx_cur) : &tmp,
7716 new ? (new + idx_new) : &tmp,
7717 sizeof(struct sched_domain_attr));
7721 * Partition sched domains as specified by the 'ndoms_new'
7722 * cpumasks in the array doms_new[] of cpumasks. This compares
7723 * doms_new[] to the current sched domain partitioning, doms_cur[].
7724 * It destroys each deleted domain and builds each new domain.
7726 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7727 * The masks don't intersect (don't overlap.) We should setup one
7728 * sched domain for each mask. CPUs not in any of the cpumasks will
7729 * not be load balanced. If the same cpumask appears both in the
7730 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7733 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7734 * ownership of it and will kfree it when done with it. If the caller
7735 * failed the kmalloc call, then it can pass in doms_new == NULL &&
7736 * ndoms_new == 1, and partition_sched_domains() will fallback to
7737 * the single partition 'fallback_doms', it also forces the domains
7740 * If doms_new == NULL it will be replaced with cpu_online_map.
7741 * ndoms_new == 0 is a special case for destroying existing domains,
7742 * and it will not create the default domain.
7744 * Call with hotplug lock held
7746 void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
7747 struct sched_domain_attr *dattr_new)
7751 mutex_lock(&sched_domains_mutex);
7753 /* always unregister in case we don't destroy any domains */
7754 unregister_sched_domain_sysctl();
7756 n = doms_new ? ndoms_new : 0;
7758 /* Destroy deleted domains */
7759 for (i = 0; i < ndoms_cur; i++) {
7760 for (j = 0; j < n; j++) {
7761 if (cpus_equal(doms_cur[i], doms_new[j])
7762 && dattrs_equal(dattr_cur, i, dattr_new, j))
7765 /* no match - a current sched domain not in new doms_new[] */
7766 detach_destroy_domains(doms_cur + i);
7771 if (doms_new == NULL) {
7773 doms_new = &fallback_doms;
7774 cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
7775 WARN_ON_ONCE(dattr_new);
7778 /* Build new domains */
7779 for (i = 0; i < ndoms_new; i++) {
7780 for (j = 0; j < ndoms_cur; j++) {
7781 if (cpus_equal(doms_new[i], doms_cur[j])
7782 && dattrs_equal(dattr_new, i, dattr_cur, j))
7785 /* no match - add a new doms_new */
7786 __build_sched_domains(doms_new + i,
7787 dattr_new ? dattr_new + i : NULL);
7792 /* Remember the new sched domains */
7793 if (doms_cur != &fallback_doms)
7795 kfree(dattr_cur); /* kfree(NULL) is safe */
7796 doms_cur = doms_new;
7797 dattr_cur = dattr_new;
7798 ndoms_cur = ndoms_new;
7800 register_sched_domain_sysctl();
7802 mutex_unlock(&sched_domains_mutex);
7805 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7806 int arch_reinit_sched_domains(void)
7810 /* Destroy domains first to force the rebuild */
7811 partition_sched_domains(0, NULL, NULL);
7813 rebuild_sched_domains();
7819 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
7823 if (buf[0] != '0' && buf[0] != '1')
7827 sched_smt_power_savings = (buf[0] == '1');
7829 sched_mc_power_savings = (buf[0] == '1');
7831 ret = arch_reinit_sched_domains();
7833 return ret ? ret : count;
7836 #ifdef CONFIG_SCHED_MC
7837 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
7840 return sprintf(page, "%u\n", sched_mc_power_savings);
7842 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
7843 const char *buf, size_t count)
7845 return sched_power_savings_store(buf, count, 0);
7847 static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
7848 sched_mc_power_savings_show,
7849 sched_mc_power_savings_store);
7852 #ifdef CONFIG_SCHED_SMT
7853 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
7856 return sprintf(page, "%u\n", sched_smt_power_savings);
7858 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
7859 const char *buf, size_t count)
7861 return sched_power_savings_store(buf, count, 1);
7863 static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
7864 sched_smt_power_savings_show,
7865 sched_smt_power_savings_store);
7868 int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
7872 #ifdef CONFIG_SCHED_SMT
7874 err = sysfs_create_file(&cls->kset.kobj,
7875 &attr_sched_smt_power_savings.attr);
7877 #ifdef CONFIG_SCHED_MC
7878 if (!err && mc_capable())
7879 err = sysfs_create_file(&cls->kset.kobj,
7880 &attr_sched_mc_power_savings.attr);
7884 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7886 #ifndef CONFIG_CPUSETS
7888 * Add online and remove offline CPUs from the scheduler domains.
7889 * When cpusets are enabled they take over this function.
7891 static int update_sched_domains(struct notifier_block *nfb,
7892 unsigned long action, void *hcpu)
7896 case CPU_ONLINE_FROZEN:
7898 case CPU_DEAD_FROZEN:
7899 partition_sched_domains(1, NULL, NULL);
7908 static int update_runtime(struct notifier_block *nfb,
7909 unsigned long action, void *hcpu)
7911 int cpu = (int)(long)hcpu;
7914 case CPU_DOWN_PREPARE:
7915 case CPU_DOWN_PREPARE_FROZEN:
7916 disable_runtime(cpu_rq(cpu));
7919 case CPU_DOWN_FAILED:
7920 case CPU_DOWN_FAILED_FROZEN:
7922 case CPU_ONLINE_FROZEN:
7923 enable_runtime(cpu_rq(cpu));
7931 void __init sched_init_smp(void)
7933 cpumask_t non_isolated_cpus;
7935 #if defined(CONFIG_NUMA)
7936 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
7938 BUG_ON(sched_group_nodes_bycpu == NULL);
7941 mutex_lock(&sched_domains_mutex);
7942 arch_init_sched_domains(&cpu_online_map);
7943 cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
7944 if (cpus_empty(non_isolated_cpus))
7945 cpu_set(smp_processor_id(), non_isolated_cpus);
7946 mutex_unlock(&sched_domains_mutex);
7949 #ifndef CONFIG_CPUSETS
7950 /* XXX: Theoretical race here - CPU may be hotplugged now */
7951 hotcpu_notifier(update_sched_domains, 0);
7954 /* RT runtime code needs to handle some hotplug events */
7955 hotcpu_notifier(update_runtime, 0);
7959 /* Move init over to a non-isolated CPU */
7960 if (set_cpus_allowed_ptr(current, &non_isolated_cpus) < 0)
7962 sched_init_granularity();
7965 void __init sched_init_smp(void)
7967 sched_init_granularity();
7969 #endif /* CONFIG_SMP */
7971 int in_sched_functions(unsigned long addr)
7973 return in_lock_functions(addr) ||
7974 (addr >= (unsigned long)__sched_text_start
7975 && addr < (unsigned long)__sched_text_end);
7978 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
7980 cfs_rq->tasks_timeline = RB_ROOT;
7981 INIT_LIST_HEAD(&cfs_rq->tasks);
7982 #ifdef CONFIG_FAIR_GROUP_SCHED
7985 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
7988 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
7990 struct rt_prio_array *array;
7993 array = &rt_rq->active;
7994 for (i = 0; i < MAX_RT_PRIO; i++) {
7995 INIT_LIST_HEAD(array->queue + i);
7996 __clear_bit(i, array->bitmap);
7998 /* delimiter for bitsearch: */
7999 __set_bit(MAX_RT_PRIO, array->bitmap);
8001 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8002 rt_rq->highest_prio = MAX_RT_PRIO;
8005 rt_rq->rt_nr_migratory = 0;
8006 rt_rq->overloaded = 0;
8010 rt_rq->rt_throttled = 0;
8011 rt_rq->rt_runtime = 0;
8012 spin_lock_init(&rt_rq->rt_runtime_lock);
8014 #ifdef CONFIG_RT_GROUP_SCHED
8015 rt_rq->rt_nr_boosted = 0;
8020 #ifdef CONFIG_FAIR_GROUP_SCHED
8021 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
8022 struct sched_entity *se, int cpu, int add,
8023 struct sched_entity *parent)
8025 struct rq *rq = cpu_rq(cpu);
8026 tg->cfs_rq[cpu] = cfs_rq;
8027 init_cfs_rq(cfs_rq, rq);
8030 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
8033 /* se could be NULL for init_task_group */
8038 se->cfs_rq = &rq->cfs;
8040 se->cfs_rq = parent->my_q;
8043 se->load.weight = tg->shares;
8044 se->load.inv_weight = 0;
8045 se->parent = parent;
8049 #ifdef CONFIG_RT_GROUP_SCHED
8050 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
8051 struct sched_rt_entity *rt_se, int cpu, int add,
8052 struct sched_rt_entity *parent)
8054 struct rq *rq = cpu_rq(cpu);
8056 tg->rt_rq[cpu] = rt_rq;
8057 init_rt_rq(rt_rq, rq);
8059 rt_rq->rt_se = rt_se;
8060 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
8062 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
8064 tg->rt_se[cpu] = rt_se;
8069 rt_se->rt_rq = &rq->rt;
8071 rt_se->rt_rq = parent->my_q;
8073 rt_se->my_q = rt_rq;
8074 rt_se->parent = parent;
8075 INIT_LIST_HEAD(&rt_se->run_list);
8079 void __init sched_init(void)
8082 unsigned long alloc_size = 0, ptr;
8084 #ifdef CONFIG_FAIR_GROUP_SCHED
8085 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8087 #ifdef CONFIG_RT_GROUP_SCHED
8088 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8090 #ifdef CONFIG_USER_SCHED
8094 * As sched_init() is called before page_alloc is setup,
8095 * we use alloc_bootmem().
8098 ptr = (unsigned long)alloc_bootmem(alloc_size);
8100 #ifdef CONFIG_FAIR_GROUP_SCHED
8101 init_task_group.se = (struct sched_entity **)ptr;
8102 ptr += nr_cpu_ids * sizeof(void **);
8104 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
8105 ptr += nr_cpu_ids * sizeof(void **);
8107 #ifdef CONFIG_USER_SCHED
8108 root_task_group.se = (struct sched_entity **)ptr;
8109 ptr += nr_cpu_ids * sizeof(void **);
8111 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
8112 ptr += nr_cpu_ids * sizeof(void **);
8113 #endif /* CONFIG_USER_SCHED */
8114 #endif /* CONFIG_FAIR_GROUP_SCHED */
8115 #ifdef CONFIG_RT_GROUP_SCHED
8116 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
8117 ptr += nr_cpu_ids * sizeof(void **);
8119 init_task_group.rt_rq = (struct rt_rq **)ptr;
8120 ptr += nr_cpu_ids * sizeof(void **);
8122 #ifdef CONFIG_USER_SCHED
8123 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
8124 ptr += nr_cpu_ids * sizeof(void **);
8126 root_task_group.rt_rq = (struct rt_rq **)ptr;
8127 ptr += nr_cpu_ids * sizeof(void **);
8128 #endif /* CONFIG_USER_SCHED */
8129 #endif /* CONFIG_RT_GROUP_SCHED */
8133 init_defrootdomain();
8136 init_rt_bandwidth(&def_rt_bandwidth,
8137 global_rt_period(), global_rt_runtime());
8139 #ifdef CONFIG_RT_GROUP_SCHED
8140 init_rt_bandwidth(&init_task_group.rt_bandwidth,
8141 global_rt_period(), global_rt_runtime());
8142 #ifdef CONFIG_USER_SCHED
8143 init_rt_bandwidth(&root_task_group.rt_bandwidth,
8144 global_rt_period(), RUNTIME_INF);
8145 #endif /* CONFIG_USER_SCHED */
8146 #endif /* CONFIG_RT_GROUP_SCHED */
8148 #ifdef CONFIG_GROUP_SCHED
8149 list_add(&init_task_group.list, &task_groups);
8150 INIT_LIST_HEAD(&init_task_group.children);
8152 #ifdef CONFIG_USER_SCHED
8153 INIT_LIST_HEAD(&root_task_group.children);
8154 init_task_group.parent = &root_task_group;
8155 list_add(&init_task_group.siblings, &root_task_group.children);
8156 #endif /* CONFIG_USER_SCHED */
8157 #endif /* CONFIG_GROUP_SCHED */
8159 for_each_possible_cpu(i) {
8163 spin_lock_init(&rq->lock);
8165 init_cfs_rq(&rq->cfs, rq);
8166 init_rt_rq(&rq->rt, rq);
8167 #ifdef CONFIG_FAIR_GROUP_SCHED
8168 init_task_group.shares = init_task_group_load;
8169 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
8170 #ifdef CONFIG_CGROUP_SCHED
8172 * How much cpu bandwidth does init_task_group get?
8174 * In case of task-groups formed thr' the cgroup filesystem, it
8175 * gets 100% of the cpu resources in the system. This overall
8176 * system cpu resource is divided among the tasks of
8177 * init_task_group and its child task-groups in a fair manner,
8178 * based on each entity's (task or task-group's) weight
8179 * (se->load.weight).
8181 * In other words, if init_task_group has 10 tasks of weight
8182 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8183 * then A0's share of the cpu resource is:
8185 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8187 * We achieve this by letting init_task_group's tasks sit
8188 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8190 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
8191 #elif defined CONFIG_USER_SCHED
8192 root_task_group.shares = NICE_0_LOAD;
8193 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
8195 * In case of task-groups formed thr' the user id of tasks,
8196 * init_task_group represents tasks belonging to root user.
8197 * Hence it forms a sibling of all subsequent groups formed.
8198 * In this case, init_task_group gets only a fraction of overall
8199 * system cpu resource, based on the weight assigned to root
8200 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8201 * by letting tasks of init_task_group sit in a separate cfs_rq
8202 * (init_cfs_rq) and having one entity represent this group of
8203 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8205 init_tg_cfs_entry(&init_task_group,
8206 &per_cpu(init_cfs_rq, i),
8207 &per_cpu(init_sched_entity, i), i, 1,
8208 root_task_group.se[i]);
8211 #endif /* CONFIG_FAIR_GROUP_SCHED */
8213 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
8214 #ifdef CONFIG_RT_GROUP_SCHED
8215 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
8216 #ifdef CONFIG_CGROUP_SCHED
8217 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
8218 #elif defined CONFIG_USER_SCHED
8219 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
8220 init_tg_rt_entry(&init_task_group,
8221 &per_cpu(init_rt_rq, i),
8222 &per_cpu(init_sched_rt_entity, i), i, 1,
8223 root_task_group.rt_se[i]);
8227 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
8228 rq->cpu_load[j] = 0;
8232 rq->active_balance = 0;
8233 rq->next_balance = jiffies;
8237 rq->migration_thread = NULL;
8238 INIT_LIST_HEAD(&rq->migration_queue);
8239 rq_attach_root(rq, &def_root_domain);
8242 atomic_set(&rq->nr_iowait, 0);
8245 set_load_weight(&init_task);
8247 #ifdef CONFIG_PREEMPT_NOTIFIERS
8248 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
8252 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
8255 #ifdef CONFIG_RT_MUTEXES
8256 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
8260 * The boot idle thread does lazy MMU switching as well:
8262 atomic_inc(&init_mm.mm_count);
8263 enter_lazy_tlb(&init_mm, current);
8266 * Make us the idle thread. Technically, schedule() should not be
8267 * called from this thread, however somewhere below it might be,
8268 * but because we are the idle thread, we just pick up running again
8269 * when this runqueue becomes "idle".
8271 init_idle(current, smp_processor_id());
8273 * During early bootup we pretend to be a normal task:
8275 current->sched_class = &fair_sched_class;
8277 scheduler_running = 1;
8280 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
8281 void __might_sleep(char *file, int line)
8284 static unsigned long prev_jiffy; /* ratelimiting */
8286 if ((!in_atomic() && !irqs_disabled()) ||
8287 system_state != SYSTEM_RUNNING || oops_in_progress)
8289 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
8291 prev_jiffy = jiffies;
8294 "BUG: sleeping function called from invalid context at %s:%d\n",
8297 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
8298 in_atomic(), irqs_disabled(),
8299 current->pid, current->comm);
8301 debug_show_held_locks(current);
8302 if (irqs_disabled())
8303 print_irqtrace_events(current);
8307 EXPORT_SYMBOL(__might_sleep);
8310 #ifdef CONFIG_MAGIC_SYSRQ
8311 static void normalize_task(struct rq *rq, struct task_struct *p)
8315 update_rq_clock(rq);
8316 on_rq = p->se.on_rq;
8318 deactivate_task(rq, p, 0);
8319 __setscheduler(rq, p, SCHED_NORMAL, 0);
8321 activate_task(rq, p, 0);
8322 resched_task(rq->curr);
8326 void normalize_rt_tasks(void)
8328 struct task_struct *g, *p;
8329 unsigned long flags;
8332 read_lock_irqsave(&tasklist_lock, flags);
8333 do_each_thread(g, p) {
8335 * Only normalize user tasks:
8340 p->se.exec_start = 0;
8341 #ifdef CONFIG_SCHEDSTATS
8342 p->se.wait_start = 0;
8343 p->se.sleep_start = 0;
8344 p->se.block_start = 0;
8349 * Renice negative nice level userspace
8352 if (TASK_NICE(p) < 0 && p->mm)
8353 set_user_nice(p, 0);
8357 spin_lock(&p->pi_lock);
8358 rq = __task_rq_lock(p);
8360 normalize_task(rq, p);
8362 __task_rq_unlock(rq);
8363 spin_unlock(&p->pi_lock);
8364 } while_each_thread(g, p);
8366 read_unlock_irqrestore(&tasklist_lock, flags);
8369 #endif /* CONFIG_MAGIC_SYSRQ */
8373 * These functions are only useful for the IA64 MCA handling.
8375 * They can only be called when the whole system has been
8376 * stopped - every CPU needs to be quiescent, and no scheduling
8377 * activity can take place. Using them for anything else would
8378 * be a serious bug, and as a result, they aren't even visible
8379 * under any other configuration.
8383 * curr_task - return the current task for a given cpu.
8384 * @cpu: the processor in question.
8386 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8388 struct task_struct *curr_task(int cpu)
8390 return cpu_curr(cpu);
8394 * set_curr_task - set the current task for a given cpu.
8395 * @cpu: the processor in question.
8396 * @p: the task pointer to set.
8398 * Description: This function must only be used when non-maskable interrupts
8399 * are serviced on a separate stack. It allows the architecture to switch the
8400 * notion of the current task on a cpu in a non-blocking manner. This function
8401 * must be called with all CPU's synchronized, and interrupts disabled, the
8402 * and caller must save the original value of the current task (see
8403 * curr_task() above) and restore that value before reenabling interrupts and
8404 * re-starting the system.
8406 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8408 void set_curr_task(int cpu, struct task_struct *p)
8415 #ifdef CONFIG_FAIR_GROUP_SCHED
8416 static void free_fair_sched_group(struct task_group *tg)
8420 for_each_possible_cpu(i) {
8422 kfree(tg->cfs_rq[i]);
8432 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8434 struct cfs_rq *cfs_rq;
8435 struct sched_entity *se;
8439 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
8442 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
8446 tg->shares = NICE_0_LOAD;
8448 for_each_possible_cpu(i) {
8451 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
8452 GFP_KERNEL, cpu_to_node(i));
8456 se = kzalloc_node(sizeof(struct sched_entity),
8457 GFP_KERNEL, cpu_to_node(i));
8461 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
8470 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8472 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
8473 &cpu_rq(cpu)->leaf_cfs_rq_list);
8476 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8478 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
8480 #else /* !CONFG_FAIR_GROUP_SCHED */
8481 static inline void free_fair_sched_group(struct task_group *tg)
8486 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
8491 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8495 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8498 #endif /* CONFIG_FAIR_GROUP_SCHED */
8500 #ifdef CONFIG_RT_GROUP_SCHED
8501 static void free_rt_sched_group(struct task_group *tg)
8505 destroy_rt_bandwidth(&tg->rt_bandwidth);
8507 for_each_possible_cpu(i) {
8509 kfree(tg->rt_rq[i]);
8511 kfree(tg->rt_se[i]);
8519 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8521 struct rt_rq *rt_rq;
8522 struct sched_rt_entity *rt_se;
8526 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
8529 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
8533 init_rt_bandwidth(&tg->rt_bandwidth,
8534 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
8536 for_each_possible_cpu(i) {
8539 rt_rq = kzalloc_node(sizeof(struct rt_rq),
8540 GFP_KERNEL, cpu_to_node(i));
8544 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
8545 GFP_KERNEL, cpu_to_node(i));
8549 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
8558 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8560 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
8561 &cpu_rq(cpu)->leaf_rt_rq_list);
8564 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8566 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
8568 #else /* !CONFIG_RT_GROUP_SCHED */
8569 static inline void free_rt_sched_group(struct task_group *tg)
8574 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
8579 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8583 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8586 #endif /* CONFIG_RT_GROUP_SCHED */
8588 #ifdef CONFIG_GROUP_SCHED
8589 static void free_sched_group(struct task_group *tg)
8591 free_fair_sched_group(tg);
8592 free_rt_sched_group(tg);
8596 /* allocate runqueue etc for a new task group */
8597 struct task_group *sched_create_group(struct task_group *parent)
8599 struct task_group *tg;
8600 unsigned long flags;
8603 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
8605 return ERR_PTR(-ENOMEM);
8607 if (!alloc_fair_sched_group(tg, parent))
8610 if (!alloc_rt_sched_group(tg, parent))
8613 spin_lock_irqsave(&task_group_lock, flags);
8614 for_each_possible_cpu(i) {
8615 register_fair_sched_group(tg, i);
8616 register_rt_sched_group(tg, i);
8618 list_add_rcu(&tg->list, &task_groups);
8620 WARN_ON(!parent); /* root should already exist */
8622 tg->parent = parent;
8623 INIT_LIST_HEAD(&tg->children);
8624 list_add_rcu(&tg->siblings, &parent->children);
8625 spin_unlock_irqrestore(&task_group_lock, flags);
8630 free_sched_group(tg);
8631 return ERR_PTR(-ENOMEM);
8634 /* rcu callback to free various structures associated with a task group */
8635 static void free_sched_group_rcu(struct rcu_head *rhp)
8637 /* now it should be safe to free those cfs_rqs */
8638 free_sched_group(container_of(rhp, struct task_group, rcu));
8641 /* Destroy runqueue etc associated with a task group */
8642 void sched_destroy_group(struct task_group *tg)
8644 unsigned long flags;
8647 spin_lock_irqsave(&task_group_lock, flags);
8648 for_each_possible_cpu(i) {
8649 unregister_fair_sched_group(tg, i);
8650 unregister_rt_sched_group(tg, i);
8652 list_del_rcu(&tg->list);
8653 list_del_rcu(&tg->siblings);
8654 spin_unlock_irqrestore(&task_group_lock, flags);
8656 /* wait for possible concurrent references to cfs_rqs complete */
8657 call_rcu(&tg->rcu, free_sched_group_rcu);
8660 /* change task's runqueue when it moves between groups.
8661 * The caller of this function should have put the task in its new group
8662 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8663 * reflect its new group.
8665 void sched_move_task(struct task_struct *tsk)
8668 unsigned long flags;
8671 rq = task_rq_lock(tsk, &flags);
8673 update_rq_clock(rq);
8675 running = task_current(rq, tsk);
8676 on_rq = tsk->se.on_rq;
8679 dequeue_task(rq, tsk, 0);
8680 if (unlikely(running))
8681 tsk->sched_class->put_prev_task(rq, tsk);
8683 set_task_rq(tsk, task_cpu(tsk));
8685 #ifdef CONFIG_FAIR_GROUP_SCHED
8686 if (tsk->sched_class->moved_group)
8687 tsk->sched_class->moved_group(tsk);
8690 if (unlikely(running))
8691 tsk->sched_class->set_curr_task(rq);
8693 enqueue_task(rq, tsk, 0);
8695 task_rq_unlock(rq, &flags);
8697 #endif /* CONFIG_GROUP_SCHED */
8699 #ifdef CONFIG_FAIR_GROUP_SCHED
8700 static void __set_se_shares(struct sched_entity *se, unsigned long shares)
8702 struct cfs_rq *cfs_rq = se->cfs_rq;
8707 dequeue_entity(cfs_rq, se, 0);
8709 se->load.weight = shares;
8710 se->load.inv_weight = 0;
8713 enqueue_entity(cfs_rq, se, 0);
8716 static void set_se_shares(struct sched_entity *se, unsigned long shares)
8718 struct cfs_rq *cfs_rq = se->cfs_rq;
8719 struct rq *rq = cfs_rq->rq;
8720 unsigned long flags;
8722 spin_lock_irqsave(&rq->lock, flags);
8723 __set_se_shares(se, shares);
8724 spin_unlock_irqrestore(&rq->lock, flags);
8727 static DEFINE_MUTEX(shares_mutex);
8729 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
8732 unsigned long flags;
8735 * We can't change the weight of the root cgroup.
8740 if (shares < MIN_SHARES)
8741 shares = MIN_SHARES;
8742 else if (shares > MAX_SHARES)
8743 shares = MAX_SHARES;
8745 mutex_lock(&shares_mutex);
8746 if (tg->shares == shares)
8749 spin_lock_irqsave(&task_group_lock, flags);
8750 for_each_possible_cpu(i)
8751 unregister_fair_sched_group(tg, i);
8752 list_del_rcu(&tg->siblings);
8753 spin_unlock_irqrestore(&task_group_lock, flags);
8755 /* wait for any ongoing reference to this group to finish */
8756 synchronize_sched();
8759 * Now we are free to modify the group's share on each cpu
8760 * w/o tripping rebalance_share or load_balance_fair.
8762 tg->shares = shares;
8763 for_each_possible_cpu(i) {
8767 cfs_rq_set_shares(tg->cfs_rq[i], 0);
8768 set_se_shares(tg->se[i], shares);
8772 * Enable load balance activity on this group, by inserting it back on
8773 * each cpu's rq->leaf_cfs_rq_list.
8775 spin_lock_irqsave(&task_group_lock, flags);
8776 for_each_possible_cpu(i)
8777 register_fair_sched_group(tg, i);
8778 list_add_rcu(&tg->siblings, &tg->parent->children);
8779 spin_unlock_irqrestore(&task_group_lock, flags);
8781 mutex_unlock(&shares_mutex);
8785 unsigned long sched_group_shares(struct task_group *tg)
8791 #ifdef CONFIG_RT_GROUP_SCHED
8793 * Ensure that the real time constraints are schedulable.
8795 static DEFINE_MUTEX(rt_constraints_mutex);
8797 static unsigned long to_ratio(u64 period, u64 runtime)
8799 if (runtime == RUNTIME_INF)
8802 return div64_u64(runtime << 20, period);
8805 /* Must be called with tasklist_lock held */
8806 static inline int tg_has_rt_tasks(struct task_group *tg)
8808 struct task_struct *g, *p;
8810 do_each_thread(g, p) {
8811 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
8813 } while_each_thread(g, p);
8818 struct rt_schedulable_data {
8819 struct task_group *tg;
8824 static int tg_schedulable(struct task_group *tg, void *data)
8826 struct rt_schedulable_data *d = data;
8827 struct task_group *child;
8828 unsigned long total, sum = 0;
8829 u64 period, runtime;
8831 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8832 runtime = tg->rt_bandwidth.rt_runtime;
8835 period = d->rt_period;
8836 runtime = d->rt_runtime;
8840 * Cannot have more runtime than the period.
8842 if (runtime > period && runtime != RUNTIME_INF)
8846 * Ensure we don't starve existing RT tasks.
8848 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
8851 total = to_ratio(period, runtime);
8854 * Nobody can have more than the global setting allows.
8856 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
8860 * The sum of our children's runtime should not exceed our own.
8862 list_for_each_entry_rcu(child, &tg->children, siblings) {
8863 period = ktime_to_ns(child->rt_bandwidth.rt_period);
8864 runtime = child->rt_bandwidth.rt_runtime;
8866 if (child == d->tg) {
8867 period = d->rt_period;
8868 runtime = d->rt_runtime;
8871 sum += to_ratio(period, runtime);
8880 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
8882 struct rt_schedulable_data data = {
8884 .rt_period = period,
8885 .rt_runtime = runtime,
8888 return walk_tg_tree(tg_schedulable, tg_nop, &data);
8891 static int tg_set_bandwidth(struct task_group *tg,
8892 u64 rt_period, u64 rt_runtime)
8896 mutex_lock(&rt_constraints_mutex);
8897 read_lock(&tasklist_lock);
8898 err = __rt_schedulable(tg, rt_period, rt_runtime);
8902 spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8903 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
8904 tg->rt_bandwidth.rt_runtime = rt_runtime;
8906 for_each_possible_cpu(i) {
8907 struct rt_rq *rt_rq = tg->rt_rq[i];
8909 spin_lock(&rt_rq->rt_runtime_lock);
8910 rt_rq->rt_runtime = rt_runtime;
8911 spin_unlock(&rt_rq->rt_runtime_lock);
8913 spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
8915 read_unlock(&tasklist_lock);
8916 mutex_unlock(&rt_constraints_mutex);
8921 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
8923 u64 rt_runtime, rt_period;
8925 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8926 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
8927 if (rt_runtime_us < 0)
8928 rt_runtime = RUNTIME_INF;
8930 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8933 long sched_group_rt_runtime(struct task_group *tg)
8937 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
8940 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
8941 do_div(rt_runtime_us, NSEC_PER_USEC);
8942 return rt_runtime_us;
8945 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
8947 u64 rt_runtime, rt_period;
8949 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
8950 rt_runtime = tg->rt_bandwidth.rt_runtime;
8955 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8958 long sched_group_rt_period(struct task_group *tg)
8962 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
8963 do_div(rt_period_us, NSEC_PER_USEC);
8964 return rt_period_us;
8967 static int sched_rt_global_constraints(void)
8969 u64 runtime, period;
8972 if (sysctl_sched_rt_period <= 0)
8975 runtime = global_rt_runtime();
8976 period = global_rt_period();
8979 * Sanity check on the sysctl variables.
8981 if (runtime > period && runtime != RUNTIME_INF)
8984 mutex_lock(&rt_constraints_mutex);
8985 read_lock(&tasklist_lock);
8986 ret = __rt_schedulable(NULL, 0, 0);
8987 read_unlock(&tasklist_lock);
8988 mutex_unlock(&rt_constraints_mutex);
8992 #else /* !CONFIG_RT_GROUP_SCHED */
8993 static int sched_rt_global_constraints(void)
8995 unsigned long flags;
8998 if (sysctl_sched_rt_period <= 0)
9001 spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
9002 for_each_possible_cpu(i) {
9003 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
9005 spin_lock(&rt_rq->rt_runtime_lock);
9006 rt_rq->rt_runtime = global_rt_runtime();
9007 spin_unlock(&rt_rq->rt_runtime_lock);
9009 spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
9013 #endif /* CONFIG_RT_GROUP_SCHED */
9015 int sched_rt_handler(struct ctl_table *table, int write,
9016 struct file *filp, void __user *buffer, size_t *lenp,
9020 int old_period, old_runtime;
9021 static DEFINE_MUTEX(mutex);
9024 old_period = sysctl_sched_rt_period;
9025 old_runtime = sysctl_sched_rt_runtime;
9027 ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
9029 if (!ret && write) {
9030 ret = sched_rt_global_constraints();
9032 sysctl_sched_rt_period = old_period;
9033 sysctl_sched_rt_runtime = old_runtime;
9035 def_rt_bandwidth.rt_runtime = global_rt_runtime();
9036 def_rt_bandwidth.rt_period =
9037 ns_to_ktime(global_rt_period());
9040 mutex_unlock(&mutex);
9045 #ifdef CONFIG_CGROUP_SCHED
9047 /* return corresponding task_group object of a cgroup */
9048 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
9050 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
9051 struct task_group, css);
9054 static struct cgroup_subsys_state *
9055 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
9057 struct task_group *tg, *parent;
9059 if (!cgrp->parent) {
9060 /* This is early initialization for the top cgroup */
9061 return &init_task_group.css;
9064 parent = cgroup_tg(cgrp->parent);
9065 tg = sched_create_group(parent);
9067 return ERR_PTR(-ENOMEM);
9073 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
9075 struct task_group *tg = cgroup_tg(cgrp);
9077 sched_destroy_group(tg);
9081 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9082 struct task_struct *tsk)
9084 #ifdef CONFIG_RT_GROUP_SCHED
9085 /* Don't accept realtime tasks when there is no way for them to run */
9086 if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
9089 /* We don't support RT-tasks being in separate groups */
9090 if (tsk->sched_class != &fair_sched_class)
9098 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9099 struct cgroup *old_cont, struct task_struct *tsk)
9101 sched_move_task(tsk);
9104 #ifdef CONFIG_FAIR_GROUP_SCHED
9105 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
9108 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
9111 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
9113 struct task_group *tg = cgroup_tg(cgrp);
9115 return (u64) tg->shares;
9117 #endif /* CONFIG_FAIR_GROUP_SCHED */
9119 #ifdef CONFIG_RT_GROUP_SCHED
9120 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
9123 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
9126 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
9128 return sched_group_rt_runtime(cgroup_tg(cgrp));
9131 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
9134 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
9137 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
9139 return sched_group_rt_period(cgroup_tg(cgrp));
9141 #endif /* CONFIG_RT_GROUP_SCHED */
9143 static struct cftype cpu_files[] = {
9144 #ifdef CONFIG_FAIR_GROUP_SCHED
9147 .read_u64 = cpu_shares_read_u64,
9148 .write_u64 = cpu_shares_write_u64,
9151 #ifdef CONFIG_RT_GROUP_SCHED
9153 .name = "rt_runtime_us",
9154 .read_s64 = cpu_rt_runtime_read,
9155 .write_s64 = cpu_rt_runtime_write,
9158 .name = "rt_period_us",
9159 .read_u64 = cpu_rt_period_read_uint,
9160 .write_u64 = cpu_rt_period_write_uint,
9165 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
9167 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
9170 struct cgroup_subsys cpu_cgroup_subsys = {
9172 .create = cpu_cgroup_create,
9173 .destroy = cpu_cgroup_destroy,
9174 .can_attach = cpu_cgroup_can_attach,
9175 .attach = cpu_cgroup_attach,
9176 .populate = cpu_cgroup_populate,
9177 .subsys_id = cpu_cgroup_subsys_id,
9181 #endif /* CONFIG_CGROUP_SCHED */
9183 #ifdef CONFIG_CGROUP_CPUACCT
9186 * CPU accounting code for task groups.
9188 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9189 * (balbir@in.ibm.com).
9192 /* track cpu usage of a group of tasks and its child groups */
9194 struct cgroup_subsys_state css;
9195 /* cpuusage holds pointer to a u64-type object on every cpu */
9197 struct cpuacct *parent;
9200 struct cgroup_subsys cpuacct_subsys;
9202 /* return cpu accounting group corresponding to this container */
9203 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
9205 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
9206 struct cpuacct, css);
9209 /* return cpu accounting group to which this task belongs */
9210 static inline struct cpuacct *task_ca(struct task_struct *tsk)
9212 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
9213 struct cpuacct, css);
9216 /* create a new cpu accounting group */
9217 static struct cgroup_subsys_state *cpuacct_create(
9218 struct cgroup_subsys *ss, struct cgroup *cgrp)
9220 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
9223 return ERR_PTR(-ENOMEM);
9225 ca->cpuusage = alloc_percpu(u64);
9226 if (!ca->cpuusage) {
9228 return ERR_PTR(-ENOMEM);
9232 ca->parent = cgroup_ca(cgrp->parent);
9237 /* destroy an existing cpu accounting group */
9239 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
9241 struct cpuacct *ca = cgroup_ca(cgrp);
9243 free_percpu(ca->cpuusage);
9247 /* return total cpu usage (in nanoseconds) of a group */
9248 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
9250 struct cpuacct *ca = cgroup_ca(cgrp);
9251 u64 totalcpuusage = 0;
9254 for_each_possible_cpu(i) {
9255 u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
9258 * Take rq->lock to make 64-bit addition safe on 32-bit
9261 spin_lock_irq(&cpu_rq(i)->lock);
9262 totalcpuusage += *cpuusage;
9263 spin_unlock_irq(&cpu_rq(i)->lock);
9266 return totalcpuusage;
9269 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
9272 struct cpuacct *ca = cgroup_ca(cgrp);
9281 for_each_possible_cpu(i) {
9282 u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
9284 spin_lock_irq(&cpu_rq(i)->lock);
9286 spin_unlock_irq(&cpu_rq(i)->lock);
9292 static struct cftype files[] = {
9295 .read_u64 = cpuusage_read,
9296 .write_u64 = cpuusage_write,
9300 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
9302 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
9306 * charge this task's execution time to its accounting group.
9308 * called with rq->lock held.
9310 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
9315 if (!cpuacct_subsys.active)
9318 cpu = task_cpu(tsk);
9321 for (; ca; ca = ca->parent) {
9322 u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
9323 *cpuusage += cputime;
9327 struct cgroup_subsys cpuacct_subsys = {
9329 .create = cpuacct_create,
9330 .destroy = cpuacct_destroy,
9331 .populate = cpuacct_populate,
9332 .subsys_id = cpuacct_subsys_id,
9334 #endif /* CONFIG_CGROUP_CPUACCT */