4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/kthread.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/reciprocal_div.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/bootmem.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
75 #include <trace/sched.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
83 * Convert user-nice values [ -20 ... 0 ... 19 ]
84 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
87 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
88 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
89 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
92 * 'User priority' is the nice value converted to something we
93 * can work with better when scaling various scheduler parameters,
94 * it's a [ 0 ... 39 ] range.
96 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
97 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
98 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
101 * Helpers for converting nanosecond timing to jiffy resolution
103 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
105 #define NICE_0_LOAD SCHED_LOAD_SCALE
106 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
109 * These are the 'tuning knobs' of the scheduler:
111 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
112 * Timeslices get refilled after they expire.
114 #define DEF_TIMESLICE (100 * HZ / 1000)
117 * single value that denotes runtime == period, ie unlimited time.
119 #define RUNTIME_INF ((u64)~0ULL)
121 DEFINE_TRACE(sched_wait_task);
122 DEFINE_TRACE(sched_wakeup);
123 DEFINE_TRACE(sched_wakeup_new);
124 DEFINE_TRACE(sched_switch);
125 DEFINE_TRACE(sched_migrate_task);
129 static void double_rq_lock(struct rq *rq1, struct rq *rq2);
132 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
133 * Since cpu_power is a 'constant', we can use a reciprocal divide.
135 static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
137 return reciprocal_divide(load, sg->reciprocal_cpu_power);
141 * Each time a sched group cpu_power is changed,
142 * we must compute its reciprocal value
144 static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
146 sg->__cpu_power += val;
147 sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
151 static inline int rt_policy(int policy)
153 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
158 static inline int task_has_rt_policy(struct task_struct *p)
160 return rt_policy(p->policy);
164 * This is the priority-queue data structure of the RT scheduling class:
166 struct rt_prio_array {
167 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
168 struct list_head queue[MAX_RT_PRIO];
171 struct rt_bandwidth {
172 /* nests inside the rq lock: */
173 spinlock_t rt_runtime_lock;
176 struct hrtimer rt_period_timer;
179 static struct rt_bandwidth def_rt_bandwidth;
181 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
183 static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
185 struct rt_bandwidth *rt_b =
186 container_of(timer, struct rt_bandwidth, rt_period_timer);
192 now = hrtimer_cb_get_time(timer);
193 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
198 idle = do_sched_rt_period_timer(rt_b, overrun);
201 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
205 void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
207 rt_b->rt_period = ns_to_ktime(period);
208 rt_b->rt_runtime = runtime;
210 spin_lock_init(&rt_b->rt_runtime_lock);
212 hrtimer_init(&rt_b->rt_period_timer,
213 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
214 rt_b->rt_period_timer.function = sched_rt_period_timer;
217 static inline int rt_bandwidth_enabled(void)
219 return sysctl_sched_rt_runtime >= 0;
222 static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
226 if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
229 if (hrtimer_active(&rt_b->rt_period_timer))
232 spin_lock(&rt_b->rt_runtime_lock);
237 if (hrtimer_active(&rt_b->rt_period_timer))
240 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
241 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
243 soft = hrtimer_get_softexpires(&rt_b->rt_period_timer);
244 hard = hrtimer_get_expires(&rt_b->rt_period_timer);
245 delta = ktime_to_ns(ktime_sub(hard, soft));
246 __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta,
247 HRTIMER_MODE_ABS, 0);
249 spin_unlock(&rt_b->rt_runtime_lock);
252 #ifdef CONFIG_RT_GROUP_SCHED
253 static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
255 hrtimer_cancel(&rt_b->rt_period_timer);
260 * sched_domains_mutex serializes calls to arch_init_sched_domains,
261 * detach_destroy_domains and partition_sched_domains.
263 static DEFINE_MUTEX(sched_domains_mutex);
265 #ifdef CONFIG_GROUP_SCHED
267 #include <linux/cgroup.h>
271 static LIST_HEAD(task_groups);
273 /* task group related information */
275 #ifdef CONFIG_CGROUP_SCHED
276 struct cgroup_subsys_state css;
279 #ifdef CONFIG_USER_SCHED
283 #ifdef CONFIG_FAIR_GROUP_SCHED
284 /* schedulable entities of this group on each cpu */
285 struct sched_entity **se;
286 /* runqueue "owned" by this group on each cpu */
287 struct cfs_rq **cfs_rq;
288 unsigned long shares;
291 #ifdef CONFIG_RT_GROUP_SCHED
292 struct sched_rt_entity **rt_se;
293 struct rt_rq **rt_rq;
295 struct rt_bandwidth rt_bandwidth;
299 struct list_head list;
301 struct task_group *parent;
302 struct list_head siblings;
303 struct list_head children;
306 #ifdef CONFIG_USER_SCHED
308 /* Helper function to pass uid information to create_sched_user() */
309 void set_tg_uid(struct user_struct *user)
311 user->tg->uid = user->uid;
316 * Every UID task group (including init_task_group aka UID-0) will
317 * be a child to this group.
319 struct task_group root_task_group;
321 #ifdef CONFIG_FAIR_GROUP_SCHED
322 /* Default task group's sched entity on each cpu */
323 static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
324 /* Default task group's cfs_rq on each cpu */
325 static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
326 #endif /* CONFIG_FAIR_GROUP_SCHED */
328 #ifdef CONFIG_RT_GROUP_SCHED
329 static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
330 static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
331 #endif /* CONFIG_RT_GROUP_SCHED */
332 #else /* !CONFIG_USER_SCHED */
333 #define root_task_group init_task_group
334 #endif /* CONFIG_USER_SCHED */
336 /* task_group_lock serializes add/remove of task groups and also changes to
337 * a task group's cpu shares.
339 static DEFINE_SPINLOCK(task_group_lock);
342 static int root_task_group_empty(void)
344 return list_empty(&root_task_group.children);
348 #ifdef CONFIG_FAIR_GROUP_SCHED
349 #ifdef CONFIG_USER_SCHED
350 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
351 #else /* !CONFIG_USER_SCHED */
352 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
353 #endif /* CONFIG_USER_SCHED */
356 * A weight of 0 or 1 can cause arithmetics problems.
357 * A weight of a cfs_rq is the sum of weights of which entities
358 * are queued on this cfs_rq, so a weight of a entity should not be
359 * too large, so as the shares value of a task group.
360 * (The default weight is 1024 - so there's no practical
361 * limitation from this.)
364 #define MAX_SHARES (1UL << 18)
366 static int init_task_group_load = INIT_TASK_GROUP_LOAD;
369 /* Default task group.
370 * Every task in system belong to this group at bootup.
372 struct task_group init_task_group;
374 /* return group to which a task belongs */
375 static inline struct task_group *task_group(struct task_struct *p)
377 struct task_group *tg;
379 #ifdef CONFIG_USER_SCHED
381 tg = __task_cred(p)->user->tg;
383 #elif defined(CONFIG_CGROUP_SCHED)
384 tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
385 struct task_group, css);
387 tg = &init_task_group;
392 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
393 static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
395 #ifdef CONFIG_FAIR_GROUP_SCHED
396 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
397 p->se.parent = task_group(p)->se[cpu];
400 #ifdef CONFIG_RT_GROUP_SCHED
401 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
402 p->rt.parent = task_group(p)->rt_se[cpu];
409 static int root_task_group_empty(void)
415 static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
416 static inline struct task_group *task_group(struct task_struct *p)
421 #endif /* CONFIG_GROUP_SCHED */
423 /* CFS-related fields in a runqueue */
425 struct load_weight load;
426 unsigned long nr_running;
431 struct rb_root tasks_timeline;
432 struct rb_node *rb_leftmost;
434 struct list_head tasks;
435 struct list_head *balance_iterator;
438 * 'curr' points to currently running entity on this cfs_rq.
439 * It is set to NULL otherwise (i.e when none are currently running).
441 struct sched_entity *curr, *next, *last;
443 unsigned int nr_spread_over;
445 #ifdef CONFIG_FAIR_GROUP_SCHED
446 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
449 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
450 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
451 * (like users, containers etc.)
453 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
454 * list is used during load balance.
456 struct list_head leaf_cfs_rq_list;
457 struct task_group *tg; /* group that "owns" this runqueue */
461 * the part of load.weight contributed by tasks
463 unsigned long task_weight;
466 * h_load = weight * f(tg)
468 * Where f(tg) is the recursive weight fraction assigned to
471 unsigned long h_load;
474 * this cpu's part of tg->shares
476 unsigned long shares;
479 * load.weight at the time we set shares
481 unsigned long rq_weight;
486 /* Real-Time classes' related field in a runqueue: */
488 struct rt_prio_array active;
489 unsigned long rt_nr_running;
490 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
492 int curr; /* highest queued rt task prio */
494 int next; /* next highest */
499 unsigned long rt_nr_migratory;
501 struct plist_head pushable_tasks;
506 /* Nests inside the rq lock: */
507 spinlock_t rt_runtime_lock;
509 #ifdef CONFIG_RT_GROUP_SCHED
510 unsigned long rt_nr_boosted;
513 struct list_head leaf_rt_rq_list;
514 struct task_group *tg;
515 struct sched_rt_entity *rt_se;
522 * We add the notion of a root-domain which will be used to define per-domain
523 * variables. Each exclusive cpuset essentially defines an island domain by
524 * fully partitioning the member cpus from any other cpuset. Whenever a new
525 * exclusive cpuset is created, we also create and attach a new root-domain
532 cpumask_var_t online;
535 * The "RT overload" flag: it gets set if a CPU has more than
536 * one runnable RT task.
538 cpumask_var_t rto_mask;
541 struct cpupri cpupri;
543 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
545 * Preferred wake up cpu nominated by sched_mc balance that will be
546 * used when most cpus are idle in the system indicating overall very
547 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
549 unsigned int sched_mc_preferred_wakeup_cpu;
554 * By default the system creates a single root-domain with all cpus as
555 * members (mimicking the global state we have today).
557 static struct root_domain def_root_domain;
562 * This is the main, per-CPU runqueue data structure.
564 * Locking rule: those places that want to lock multiple runqueues
565 * (such as the load balancing or the thread migration code), lock
566 * acquire operations must be ordered by ascending &runqueue.
573 * nr_running and cpu_load should be in the same cacheline because
574 * remote CPUs use both these fields when doing load calculation.
576 unsigned long nr_running;
577 #define CPU_LOAD_IDX_MAX 5
578 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
580 unsigned long last_tick_seen;
581 unsigned char in_nohz_recently;
583 /* capture load from *all* tasks on this cpu: */
584 struct load_weight load;
585 unsigned long nr_load_updates;
587 u64 nr_migrations_in;
592 #ifdef CONFIG_FAIR_GROUP_SCHED
593 /* list of leaf cfs_rq on this cpu: */
594 struct list_head leaf_cfs_rq_list;
596 #ifdef CONFIG_RT_GROUP_SCHED
597 struct list_head leaf_rt_rq_list;
601 * This is part of a global counter where only the total sum
602 * over all CPUs matters. A task can increase this counter on
603 * one CPU and if it got migrated afterwards it may decrease
604 * it on another CPU. Always updated under the runqueue lock:
606 unsigned long nr_uninterruptible;
608 struct task_struct *curr, *idle;
609 unsigned long next_balance;
610 struct mm_struct *prev_mm;
617 struct root_domain *rd;
618 struct sched_domain *sd;
620 unsigned char idle_at_tick;
621 /* For active balancing */
624 /* cpu of this runqueue: */
628 unsigned long avg_load_per_task;
630 struct task_struct *migration_thread;
631 struct list_head migration_queue;
634 #ifdef CONFIG_SCHED_HRTICK
636 int hrtick_csd_pending;
637 struct call_single_data hrtick_csd;
639 struct hrtimer hrtick_timer;
642 #ifdef CONFIG_SCHEDSTATS
644 struct sched_info rq_sched_info;
645 unsigned long long rq_cpu_time;
646 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
648 /* sys_sched_yield() stats */
649 unsigned int yld_count;
651 /* schedule() stats */
652 unsigned int sched_switch;
653 unsigned int sched_count;
654 unsigned int sched_goidle;
656 /* try_to_wake_up() stats */
657 unsigned int ttwu_count;
658 unsigned int ttwu_local;
661 unsigned int bkl_count;
665 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
667 static inline void check_preempt_curr(struct rq *rq, struct task_struct *p, int sync)
669 rq->curr->sched_class->check_preempt_curr(rq, p, sync);
672 static inline int cpu_of(struct rq *rq)
682 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
683 * See detach_destroy_domains: synchronize_sched for details.
685 * The domain tree of any CPU may only be accessed from within
686 * preempt-disabled sections.
688 #define for_each_domain(cpu, __sd) \
689 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
691 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
692 #define this_rq() (&__get_cpu_var(runqueues))
693 #define task_rq(p) cpu_rq(task_cpu(p))
694 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
696 inline void update_rq_clock(struct rq *rq)
698 rq->clock = sched_clock_cpu(cpu_of(rq));
702 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
704 #ifdef CONFIG_SCHED_DEBUG
705 # define const_debug __read_mostly
707 # define const_debug static const
713 * Returns true if the current cpu runqueue is locked.
714 * This interface allows printk to be called with the runqueue lock
715 * held and know whether or not it is OK to wake up the klogd.
717 int runqueue_is_locked(void)
720 struct rq *rq = cpu_rq(cpu);
723 ret = spin_is_locked(&rq->lock);
729 * Debugging: various feature bits
732 #define SCHED_FEAT(name, enabled) \
733 __SCHED_FEAT_##name ,
736 #include "sched_features.h"
741 #define SCHED_FEAT(name, enabled) \
742 (1UL << __SCHED_FEAT_##name) * enabled |
744 const_debug unsigned int sysctl_sched_features =
745 #include "sched_features.h"
750 #ifdef CONFIG_SCHED_DEBUG
751 #define SCHED_FEAT(name, enabled) \
754 static __read_mostly char *sched_feat_names[] = {
755 #include "sched_features.h"
761 static int sched_feat_show(struct seq_file *m, void *v)
765 for (i = 0; sched_feat_names[i]; i++) {
766 if (!(sysctl_sched_features & (1UL << i)))
768 seq_printf(m, "%s ", sched_feat_names[i]);
776 sched_feat_write(struct file *filp, const char __user *ubuf,
777 size_t cnt, loff_t *ppos)
787 if (copy_from_user(&buf, ubuf, cnt))
792 if (strncmp(buf, "NO_", 3) == 0) {
797 for (i = 0; sched_feat_names[i]; i++) {
798 int len = strlen(sched_feat_names[i]);
800 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
802 sysctl_sched_features &= ~(1UL << i);
804 sysctl_sched_features |= (1UL << i);
809 if (!sched_feat_names[i])
817 static int sched_feat_open(struct inode *inode, struct file *filp)
819 return single_open(filp, sched_feat_show, NULL);
822 static struct file_operations sched_feat_fops = {
823 .open = sched_feat_open,
824 .write = sched_feat_write,
827 .release = single_release,
830 static __init int sched_init_debug(void)
832 debugfs_create_file("sched_features", 0644, NULL, NULL,
837 late_initcall(sched_init_debug);
841 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
844 * Number of tasks to iterate in a single balance run.
845 * Limited because this is done with IRQs disabled.
847 const_debug unsigned int sysctl_sched_nr_migrate = 32;
850 * ratelimit for updating the group shares.
853 unsigned int sysctl_sched_shares_ratelimit = 250000;
856 * Inject some fuzzyness into changing the per-cpu group shares
857 * this avoids remote rq-locks at the expense of fairness.
860 unsigned int sysctl_sched_shares_thresh = 4;
863 * period over which we measure -rt task cpu usage in us.
866 unsigned int sysctl_sched_rt_period = 1000000;
868 static __read_mostly int scheduler_running;
871 * part of the period that we allow rt tasks to run in us.
874 int sysctl_sched_rt_runtime = 950000;
876 static inline u64 global_rt_period(void)
878 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
881 static inline u64 global_rt_runtime(void)
883 if (sysctl_sched_rt_runtime < 0)
886 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
889 #ifndef prepare_arch_switch
890 # define prepare_arch_switch(next) do { } while (0)
892 #ifndef finish_arch_switch
893 # define finish_arch_switch(prev) do { } while (0)
896 static inline int task_current(struct rq *rq, struct task_struct *p)
898 return rq->curr == p;
901 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
902 static inline int task_running(struct rq *rq, struct task_struct *p)
904 return task_current(rq, p);
907 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
911 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
913 #ifdef CONFIG_DEBUG_SPINLOCK
914 /* this is a valid case when another task releases the spinlock */
915 rq->lock.owner = current;
918 * If we are tracking spinlock dependencies then we have to
919 * fix up the runqueue lock - which gets 'carried over' from
922 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
924 spin_unlock_irq(&rq->lock);
927 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
928 static inline int task_running(struct rq *rq, struct task_struct *p)
933 return task_current(rq, p);
937 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
941 * We can optimise this out completely for !SMP, because the
942 * SMP rebalancing from interrupt is the only thing that cares
947 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
948 spin_unlock_irq(&rq->lock);
950 spin_unlock(&rq->lock);
954 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
958 * After ->oncpu is cleared, the task can be moved to a different CPU.
959 * We must ensure this doesn't happen until the switch is completely
965 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
969 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
972 * __task_rq_lock - lock the runqueue a given task resides on.
973 * Must be called interrupts disabled.
975 static inline struct rq *__task_rq_lock(struct task_struct *p)
979 struct rq *rq = task_rq(p);
980 spin_lock(&rq->lock);
981 if (likely(rq == task_rq(p)))
983 spin_unlock(&rq->lock);
988 * task_rq_lock - lock the runqueue a given task resides on and disable
989 * interrupts. Note the ordering: we can safely lookup the task_rq without
990 * explicitly disabling preemption.
992 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
998 local_irq_save(*flags);
1000 spin_lock(&rq->lock);
1001 if (likely(rq == task_rq(p)))
1003 spin_unlock_irqrestore(&rq->lock, *flags);
1007 void task_rq_unlock_wait(struct task_struct *p)
1009 struct rq *rq = task_rq(p);
1011 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1012 spin_unlock_wait(&rq->lock);
1015 static void __task_rq_unlock(struct rq *rq)
1016 __releases(rq->lock)
1018 spin_unlock(&rq->lock);
1021 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
1022 __releases(rq->lock)
1024 spin_unlock_irqrestore(&rq->lock, *flags);
1028 * this_rq_lock - lock this runqueue and disable interrupts.
1030 static struct rq *this_rq_lock(void)
1031 __acquires(rq->lock)
1035 local_irq_disable();
1037 spin_lock(&rq->lock);
1042 #ifdef CONFIG_SCHED_HRTICK
1044 * Use HR-timers to deliver accurate preemption points.
1046 * Its all a bit involved since we cannot program an hrt while holding the
1047 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1050 * When we get rescheduled we reprogram the hrtick_timer outside of the
1056 * - enabled by features
1057 * - hrtimer is actually high res
1059 static inline int hrtick_enabled(struct rq *rq)
1061 if (!sched_feat(HRTICK))
1063 if (!cpu_active(cpu_of(rq)))
1065 return hrtimer_is_hres_active(&rq->hrtick_timer);
1068 static void hrtick_clear(struct rq *rq)
1070 if (hrtimer_active(&rq->hrtick_timer))
1071 hrtimer_cancel(&rq->hrtick_timer);
1075 * High-resolution timer tick.
1076 * Runs from hardirq context with interrupts disabled.
1078 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1080 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1082 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1084 spin_lock(&rq->lock);
1085 update_rq_clock(rq);
1086 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1087 spin_unlock(&rq->lock);
1089 return HRTIMER_NORESTART;
1094 * called from hardirq (IPI) context
1096 static void __hrtick_start(void *arg)
1098 struct rq *rq = arg;
1100 spin_lock(&rq->lock);
1101 hrtimer_restart(&rq->hrtick_timer);
1102 rq->hrtick_csd_pending = 0;
1103 spin_unlock(&rq->lock);
1107 * Called to set the hrtick timer state.
1109 * called with rq->lock held and irqs disabled
1111 static void hrtick_start(struct rq *rq, u64 delay)
1113 struct hrtimer *timer = &rq->hrtick_timer;
1114 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
1116 hrtimer_set_expires(timer, time);
1118 if (rq == this_rq()) {
1119 hrtimer_restart(timer);
1120 } else if (!rq->hrtick_csd_pending) {
1121 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
1122 rq->hrtick_csd_pending = 1;
1127 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1129 int cpu = (int)(long)hcpu;
1132 case CPU_UP_CANCELED:
1133 case CPU_UP_CANCELED_FROZEN:
1134 case CPU_DOWN_PREPARE:
1135 case CPU_DOWN_PREPARE_FROZEN:
1137 case CPU_DEAD_FROZEN:
1138 hrtick_clear(cpu_rq(cpu));
1145 static __init void init_hrtick(void)
1147 hotcpu_notifier(hotplug_hrtick, 0);
1151 * Called to set the hrtick timer state.
1153 * called with rq->lock held and irqs disabled
1155 static void hrtick_start(struct rq *rq, u64 delay)
1157 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
1158 HRTIMER_MODE_REL, 0);
1161 static inline void init_hrtick(void)
1164 #endif /* CONFIG_SMP */
1166 static void init_rq_hrtick(struct rq *rq)
1169 rq->hrtick_csd_pending = 0;
1171 rq->hrtick_csd.flags = 0;
1172 rq->hrtick_csd.func = __hrtick_start;
1173 rq->hrtick_csd.info = rq;
1176 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1177 rq->hrtick_timer.function = hrtick;
1179 #else /* CONFIG_SCHED_HRTICK */
1180 static inline void hrtick_clear(struct rq *rq)
1184 static inline void init_rq_hrtick(struct rq *rq)
1188 static inline void init_hrtick(void)
1191 #endif /* CONFIG_SCHED_HRTICK */
1194 * resched_task - mark a task 'to be rescheduled now'.
1196 * On UP this means the setting of the need_resched flag, on SMP it
1197 * might also involve a cross-CPU call to trigger the scheduler on
1202 #ifndef tsk_is_polling
1203 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1206 static void resched_task(struct task_struct *p)
1210 assert_spin_locked(&task_rq(p)->lock);
1212 if (test_tsk_need_resched(p))
1215 set_tsk_need_resched(p);
1218 if (cpu == smp_processor_id())
1221 /* NEED_RESCHED must be visible before we test polling */
1223 if (!tsk_is_polling(p))
1224 smp_send_reschedule(cpu);
1227 static void resched_cpu(int cpu)
1229 struct rq *rq = cpu_rq(cpu);
1230 unsigned long flags;
1232 if (!spin_trylock_irqsave(&rq->lock, flags))
1234 resched_task(cpu_curr(cpu));
1235 spin_unlock_irqrestore(&rq->lock, flags);
1240 * When add_timer_on() enqueues a timer into the timer wheel of an
1241 * idle CPU then this timer might expire before the next timer event
1242 * which is scheduled to wake up that CPU. In case of a completely
1243 * idle system the next event might even be infinite time into the
1244 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1245 * leaves the inner idle loop so the newly added timer is taken into
1246 * account when the CPU goes back to idle and evaluates the timer
1247 * wheel for the next timer event.
1249 void wake_up_idle_cpu(int cpu)
1251 struct rq *rq = cpu_rq(cpu);
1253 if (cpu == smp_processor_id())
1257 * This is safe, as this function is called with the timer
1258 * wheel base lock of (cpu) held. When the CPU is on the way
1259 * to idle and has not yet set rq->curr to idle then it will
1260 * be serialized on the timer wheel base lock and take the new
1261 * timer into account automatically.
1263 if (rq->curr != rq->idle)
1267 * We can set TIF_RESCHED on the idle task of the other CPU
1268 * lockless. The worst case is that the other CPU runs the
1269 * idle task through an additional NOOP schedule()
1271 set_tsk_need_resched(rq->idle);
1273 /* NEED_RESCHED must be visible before we test polling */
1275 if (!tsk_is_polling(rq->idle))
1276 smp_send_reschedule(cpu);
1278 #endif /* CONFIG_NO_HZ */
1280 #else /* !CONFIG_SMP */
1281 static void resched_task(struct task_struct *p)
1283 assert_spin_locked(&task_rq(p)->lock);
1284 set_tsk_need_resched(p);
1286 #endif /* CONFIG_SMP */
1288 #if BITS_PER_LONG == 32
1289 # define WMULT_CONST (~0UL)
1291 # define WMULT_CONST (1UL << 32)
1294 #define WMULT_SHIFT 32
1297 * Shift right and round:
1299 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1302 * delta *= weight / lw
1304 static unsigned long
1305 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1306 struct load_weight *lw)
1310 if (!lw->inv_weight) {
1311 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1314 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1318 tmp = (u64)delta_exec * weight;
1320 * Check whether we'd overflow the 64-bit multiplication:
1322 if (unlikely(tmp > WMULT_CONST))
1323 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1326 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1328 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1331 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1337 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1344 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1345 * of tasks with abnormal "nice" values across CPUs the contribution that
1346 * each task makes to its run queue's load is weighted according to its
1347 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1348 * scaled version of the new time slice allocation that they receive on time
1352 #define WEIGHT_IDLEPRIO 3
1353 #define WMULT_IDLEPRIO 1431655765
1356 * Nice levels are multiplicative, with a gentle 10% change for every
1357 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1358 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1359 * that remained on nice 0.
1361 * The "10% effect" is relative and cumulative: from _any_ nice level,
1362 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1363 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1364 * If a task goes up by ~10% and another task goes down by ~10% then
1365 * the relative distance between them is ~25%.)
1367 static const int prio_to_weight[40] = {
1368 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1369 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1370 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1371 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1372 /* 0 */ 1024, 820, 655, 526, 423,
1373 /* 5 */ 335, 272, 215, 172, 137,
1374 /* 10 */ 110, 87, 70, 56, 45,
1375 /* 15 */ 36, 29, 23, 18, 15,
1379 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1381 * In cases where the weight does not change often, we can use the
1382 * precalculated inverse to speed up arithmetics by turning divisions
1383 * into multiplications:
1385 static const u32 prio_to_wmult[40] = {
1386 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1387 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1388 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1389 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1390 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1391 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1392 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1393 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1396 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
1399 * runqueue iterator, to support SMP load-balancing between different
1400 * scheduling classes, without having to expose their internal data
1401 * structures to the load-balancing proper:
1403 struct rq_iterator {
1405 struct task_struct *(*start)(void *);
1406 struct task_struct *(*next)(void *);
1410 static unsigned long
1411 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
1412 unsigned long max_load_move, struct sched_domain *sd,
1413 enum cpu_idle_type idle, int *all_pinned,
1414 int *this_best_prio, struct rq_iterator *iterator);
1417 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
1418 struct sched_domain *sd, enum cpu_idle_type idle,
1419 struct rq_iterator *iterator);
1422 #ifdef CONFIG_CGROUP_CPUACCT
1423 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1425 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1428 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1430 update_load_add(&rq->load, load);
1433 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1435 update_load_sub(&rq->load, load);
1438 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1439 typedef int (*tg_visitor)(struct task_group *, void *);
1442 * Iterate the full tree, calling @down when first entering a node and @up when
1443 * leaving it for the final time.
1445 static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
1447 struct task_group *parent, *child;
1451 parent = &root_task_group;
1453 ret = (*down)(parent, data);
1456 list_for_each_entry_rcu(child, &parent->children, siblings) {
1463 ret = (*up)(parent, data);
1468 parent = parent->parent;
1477 static int tg_nop(struct task_group *tg, void *data)
1484 static unsigned long source_load(int cpu, int type);
1485 static unsigned long target_load(int cpu, int type);
1486 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1488 static unsigned long cpu_avg_load_per_task(int cpu)
1490 struct rq *rq = cpu_rq(cpu);
1491 unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
1494 rq->avg_load_per_task = rq->load.weight / nr_running;
1496 rq->avg_load_per_task = 0;
1498 return rq->avg_load_per_task;
1501 #ifdef CONFIG_FAIR_GROUP_SCHED
1503 static void __set_se_shares(struct sched_entity *se, unsigned long shares);
1506 * Calculate and set the cpu's group shares.
1509 update_group_shares_cpu(struct task_group *tg, int cpu,
1510 unsigned long sd_shares, unsigned long sd_rq_weight)
1512 unsigned long shares;
1513 unsigned long rq_weight;
1518 rq_weight = tg->cfs_rq[cpu]->rq_weight;
1521 * \Sum shares * rq_weight
1522 * shares = -----------------------
1526 shares = (sd_shares * rq_weight) / sd_rq_weight;
1527 shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
1529 if (abs(shares - tg->se[cpu]->load.weight) >
1530 sysctl_sched_shares_thresh) {
1531 struct rq *rq = cpu_rq(cpu);
1532 unsigned long flags;
1534 spin_lock_irqsave(&rq->lock, flags);
1535 tg->cfs_rq[cpu]->shares = shares;
1537 __set_se_shares(tg->se[cpu], shares);
1538 spin_unlock_irqrestore(&rq->lock, flags);
1543 * Re-compute the task group their per cpu shares over the given domain.
1544 * This needs to be done in a bottom-up fashion because the rq weight of a
1545 * parent group depends on the shares of its child groups.
1547 static int tg_shares_up(struct task_group *tg, void *data)
1549 unsigned long weight, rq_weight = 0;
1550 unsigned long shares = 0;
1551 struct sched_domain *sd = data;
1554 for_each_cpu(i, sched_domain_span(sd)) {
1556 * If there are currently no tasks on the cpu pretend there
1557 * is one of average load so that when a new task gets to
1558 * run here it will not get delayed by group starvation.
1560 weight = tg->cfs_rq[i]->load.weight;
1562 weight = NICE_0_LOAD;
1564 tg->cfs_rq[i]->rq_weight = weight;
1565 rq_weight += weight;
1566 shares += tg->cfs_rq[i]->shares;
1569 if ((!shares && rq_weight) || shares > tg->shares)
1570 shares = tg->shares;
1572 if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
1573 shares = tg->shares;
1575 for_each_cpu(i, sched_domain_span(sd))
1576 update_group_shares_cpu(tg, i, shares, rq_weight);
1582 * Compute the cpu's hierarchical load factor for each task group.
1583 * This needs to be done in a top-down fashion because the load of a child
1584 * group is a fraction of its parents load.
1586 static int tg_load_down(struct task_group *tg, void *data)
1589 long cpu = (long)data;
1592 load = cpu_rq(cpu)->load.weight;
1594 load = tg->parent->cfs_rq[cpu]->h_load;
1595 load *= tg->cfs_rq[cpu]->shares;
1596 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
1599 tg->cfs_rq[cpu]->h_load = load;
1604 static void update_shares(struct sched_domain *sd)
1606 u64 now = cpu_clock(raw_smp_processor_id());
1607 s64 elapsed = now - sd->last_update;
1609 if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
1610 sd->last_update = now;
1611 walk_tg_tree(tg_nop, tg_shares_up, sd);
1615 static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1617 spin_unlock(&rq->lock);
1619 spin_lock(&rq->lock);
1622 static void update_h_load(long cpu)
1624 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
1629 static inline void update_shares(struct sched_domain *sd)
1633 static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1639 #ifdef CONFIG_PREEMPT
1642 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1643 * way at the expense of forcing extra atomic operations in all
1644 * invocations. This assures that the double_lock is acquired using the
1645 * same underlying policy as the spinlock_t on this architecture, which
1646 * reduces latency compared to the unfair variant below. However, it
1647 * also adds more overhead and therefore may reduce throughput.
1649 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1650 __releases(this_rq->lock)
1651 __acquires(busiest->lock)
1652 __acquires(this_rq->lock)
1654 spin_unlock(&this_rq->lock);
1655 double_rq_lock(this_rq, busiest);
1662 * Unfair double_lock_balance: Optimizes throughput at the expense of
1663 * latency by eliminating extra atomic operations when the locks are
1664 * already in proper order on entry. This favors lower cpu-ids and will
1665 * grant the double lock to lower cpus over higher ids under contention,
1666 * regardless of entry order into the function.
1668 static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1669 __releases(this_rq->lock)
1670 __acquires(busiest->lock)
1671 __acquires(this_rq->lock)
1675 if (unlikely(!spin_trylock(&busiest->lock))) {
1676 if (busiest < this_rq) {
1677 spin_unlock(&this_rq->lock);
1678 spin_lock(&busiest->lock);
1679 spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING);
1682 spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING);
1687 #endif /* CONFIG_PREEMPT */
1690 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1692 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1694 if (unlikely(!irqs_disabled())) {
1695 /* printk() doesn't work good under rq->lock */
1696 spin_unlock(&this_rq->lock);
1700 return _double_lock_balance(this_rq, busiest);
1703 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1704 __releases(busiest->lock)
1706 spin_unlock(&busiest->lock);
1707 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1711 #ifdef CONFIG_FAIR_GROUP_SCHED
1712 static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
1715 cfs_rq->shares = shares;
1720 #include "sched_stats.h"
1721 #include "sched_idletask.c"
1722 #include "sched_fair.c"
1723 #include "sched_rt.c"
1724 #ifdef CONFIG_SCHED_DEBUG
1725 # include "sched_debug.c"
1728 #define sched_class_highest (&rt_sched_class)
1729 #define for_each_class(class) \
1730 for (class = sched_class_highest; class; class = class->next)
1732 static void inc_nr_running(struct rq *rq)
1737 static void dec_nr_running(struct rq *rq)
1742 static void set_load_weight(struct task_struct *p)
1744 if (task_has_rt_policy(p)) {
1745 p->se.load.weight = prio_to_weight[0] * 2;
1746 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1751 * SCHED_IDLE tasks get minimal weight:
1753 if (p->policy == SCHED_IDLE) {
1754 p->se.load.weight = WEIGHT_IDLEPRIO;
1755 p->se.load.inv_weight = WMULT_IDLEPRIO;
1759 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1760 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1763 static void update_avg(u64 *avg, u64 sample)
1765 s64 diff = sample - *avg;
1769 static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
1772 p->se.start_runtime = p->se.sum_exec_runtime;
1774 sched_info_queued(p);
1775 p->sched_class->enqueue_task(rq, p, wakeup);
1779 static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
1782 if (p->se.last_wakeup) {
1783 update_avg(&p->se.avg_overlap,
1784 p->se.sum_exec_runtime - p->se.last_wakeup);
1785 p->se.last_wakeup = 0;
1787 update_avg(&p->se.avg_wakeup,
1788 sysctl_sched_wakeup_granularity);
1792 sched_info_dequeued(p);
1793 p->sched_class->dequeue_task(rq, p, sleep);
1798 * __normal_prio - return the priority that is based on the static prio
1800 static inline int __normal_prio(struct task_struct *p)
1802 return p->static_prio;
1806 * Calculate the expected normal priority: i.e. priority
1807 * without taking RT-inheritance into account. Might be
1808 * boosted by interactivity modifiers. Changes upon fork,
1809 * setprio syscalls, and whenever the interactivity
1810 * estimator recalculates.
1812 static inline int normal_prio(struct task_struct *p)
1816 if (task_has_rt_policy(p))
1817 prio = MAX_RT_PRIO-1 - p->rt_priority;
1819 prio = __normal_prio(p);
1824 * Calculate the current priority, i.e. the priority
1825 * taken into account by the scheduler. This value might
1826 * be boosted by RT tasks, or might be boosted by
1827 * interactivity modifiers. Will be RT if the task got
1828 * RT-boosted. If not then it returns p->normal_prio.
1830 static int effective_prio(struct task_struct *p)
1832 p->normal_prio = normal_prio(p);
1834 * If we are RT tasks or we were boosted to RT priority,
1835 * keep the priority unchanged. Otherwise, update priority
1836 * to the normal priority:
1838 if (!rt_prio(p->prio))
1839 return p->normal_prio;
1844 * activate_task - move a task to the runqueue.
1846 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
1848 if (task_contributes_to_load(p))
1849 rq->nr_uninterruptible--;
1851 enqueue_task(rq, p, wakeup);
1856 * deactivate_task - remove a task from the runqueue.
1858 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
1860 if (task_contributes_to_load(p))
1861 rq->nr_uninterruptible++;
1863 dequeue_task(rq, p, sleep);
1868 * task_curr - is this task currently executing on a CPU?
1869 * @p: the task in question.
1871 inline int task_curr(const struct task_struct *p)
1873 return cpu_curr(task_cpu(p)) == p;
1876 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1878 set_task_rq(p, cpu);
1881 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1882 * successfuly executed on another CPU. We must ensure that updates of
1883 * per-task data have been completed by this moment.
1886 task_thread_info(p)->cpu = cpu;
1890 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1891 const struct sched_class *prev_class,
1892 int oldprio, int running)
1894 if (prev_class != p->sched_class) {
1895 if (prev_class->switched_from)
1896 prev_class->switched_from(rq, p, running);
1897 p->sched_class->switched_to(rq, p, running);
1899 p->sched_class->prio_changed(rq, p, oldprio, running);
1904 /* Used instead of source_load when we know the type == 0 */
1905 static unsigned long weighted_cpuload(const int cpu)
1907 return cpu_rq(cpu)->load.weight;
1911 * Is this task likely cache-hot:
1914 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1919 * Buddy candidates are cache hot:
1921 if (sched_feat(CACHE_HOT_BUDDY) &&
1922 (&p->se == cfs_rq_of(&p->se)->next ||
1923 &p->se == cfs_rq_of(&p->se)->last))
1926 if (p->sched_class != &fair_sched_class)
1929 if (sysctl_sched_migration_cost == -1)
1931 if (sysctl_sched_migration_cost == 0)
1934 delta = now - p->se.exec_start;
1936 return delta < (s64)sysctl_sched_migration_cost;
1940 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1942 int old_cpu = task_cpu(p);
1943 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
1944 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1945 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
1948 clock_offset = old_rq->clock - new_rq->clock;
1950 trace_sched_migrate_task(p, task_cpu(p), new_cpu);
1952 #ifdef CONFIG_SCHEDSTATS
1953 if (p->se.wait_start)
1954 p->se.wait_start -= clock_offset;
1955 if (p->se.sleep_start)
1956 p->se.sleep_start -= clock_offset;
1957 if (p->se.block_start)
1958 p->se.block_start -= clock_offset;
1960 if (old_cpu != new_cpu) {
1961 p->se.nr_migrations++;
1962 new_rq->nr_migrations_in++;
1963 #ifdef CONFIG_SCHEDSTATS
1964 if (task_hot(p, old_rq->clock, NULL))
1965 schedstat_inc(p, se.nr_forced2_migrations);
1968 p->se.vruntime -= old_cfsrq->min_vruntime -
1969 new_cfsrq->min_vruntime;
1971 __set_task_cpu(p, new_cpu);
1974 struct migration_req {
1975 struct list_head list;
1977 struct task_struct *task;
1980 struct completion done;
1984 * The task's runqueue lock must be held.
1985 * Returns true if you have to wait for migration thread.
1988 migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
1990 struct rq *rq = task_rq(p);
1993 * If the task is not on a runqueue (and not running), then
1994 * it is sufficient to simply update the task's cpu field.
1996 if (!p->se.on_rq && !task_running(rq, p)) {
1997 set_task_cpu(p, dest_cpu);
2001 init_completion(&req->done);
2003 req->dest_cpu = dest_cpu;
2004 list_add(&req->list, &rq->migration_queue);
2010 * wait_task_inactive - wait for a thread to unschedule.
2012 * If @match_state is nonzero, it's the @p->state value just checked and
2013 * not expected to change. If it changes, i.e. @p might have woken up,
2014 * then return zero. When we succeed in waiting for @p to be off its CPU,
2015 * we return a positive number (its total switch count). If a second call
2016 * a short while later returns the same number, the caller can be sure that
2017 * @p has remained unscheduled the whole time.
2019 * The caller must ensure that the task *will* unschedule sometime soon,
2020 * else this function might spin for a *long* time. This function can't
2021 * be called with interrupts off, or it may introduce deadlock with
2022 * smp_call_function() if an IPI is sent by the same process we are
2023 * waiting to become inactive.
2025 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
2027 unsigned long flags;
2034 * We do the initial early heuristics without holding
2035 * any task-queue locks at all. We'll only try to get
2036 * the runqueue lock when things look like they will
2042 * If the task is actively running on another CPU
2043 * still, just relax and busy-wait without holding
2046 * NOTE! Since we don't hold any locks, it's not
2047 * even sure that "rq" stays as the right runqueue!
2048 * But we don't care, since "task_running()" will
2049 * return false if the runqueue has changed and p
2050 * is actually now running somewhere else!
2052 while (task_running(rq, p)) {
2053 if (match_state && unlikely(p->state != match_state))
2059 * Ok, time to look more closely! We need the rq
2060 * lock now, to be *sure*. If we're wrong, we'll
2061 * just go back and repeat.
2063 rq = task_rq_lock(p, &flags);
2064 trace_sched_wait_task(rq, p);
2065 running = task_running(rq, p);
2066 on_rq = p->se.on_rq;
2068 if (!match_state || p->state == match_state)
2069 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
2070 task_rq_unlock(rq, &flags);
2073 * If it changed from the expected state, bail out now.
2075 if (unlikely(!ncsw))
2079 * Was it really running after all now that we
2080 * checked with the proper locks actually held?
2082 * Oops. Go back and try again..
2084 if (unlikely(running)) {
2090 * It's not enough that it's not actively running,
2091 * it must be off the runqueue _entirely_, and not
2094 * So if it was still runnable (but just not actively
2095 * running right now), it's preempted, and we should
2096 * yield - it could be a while.
2098 if (unlikely(on_rq)) {
2099 schedule_timeout_uninterruptible(1);
2104 * Ahh, all good. It wasn't running, and it wasn't
2105 * runnable, which means that it will never become
2106 * running in the future either. We're all done!
2115 * kick_process - kick a running thread to enter/exit the kernel
2116 * @p: the to-be-kicked thread
2118 * Cause a process which is running on another CPU to enter
2119 * kernel-mode, without any delay. (to get signals handled.)
2121 * NOTE: this function doesnt have to take the runqueue lock,
2122 * because all it wants to ensure is that the remote task enters
2123 * the kernel. If the IPI races and the task has been migrated
2124 * to another CPU then no harm is done and the purpose has been
2127 void kick_process(struct task_struct *p)
2133 if ((cpu != smp_processor_id()) && task_curr(p))
2134 smp_send_reschedule(cpu);
2139 * Return a low guess at the load of a migration-source cpu weighted
2140 * according to the scheduling class and "nice" value.
2142 * We want to under-estimate the load of migration sources, to
2143 * balance conservatively.
2145 static unsigned long source_load(int cpu, int type)
2147 struct rq *rq = cpu_rq(cpu);
2148 unsigned long total = weighted_cpuload(cpu);
2150 if (type == 0 || !sched_feat(LB_BIAS))
2153 return min(rq->cpu_load[type-1], total);
2157 * Return a high guess at the load of a migration-target cpu weighted
2158 * according to the scheduling class and "nice" value.
2160 static unsigned long target_load(int cpu, int type)
2162 struct rq *rq = cpu_rq(cpu);
2163 unsigned long total = weighted_cpuload(cpu);
2165 if (type == 0 || !sched_feat(LB_BIAS))
2168 return max(rq->cpu_load[type-1], total);
2172 * find_idlest_group finds and returns the least busy CPU group within the
2175 static struct sched_group *
2176 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
2178 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
2179 unsigned long min_load = ULONG_MAX, this_load = 0;
2180 int load_idx = sd->forkexec_idx;
2181 int imbalance = 100 + (sd->imbalance_pct-100)/2;
2184 unsigned long load, avg_load;
2188 /* Skip over this group if it has no CPUs allowed */
2189 if (!cpumask_intersects(sched_group_cpus(group),
2193 local_group = cpumask_test_cpu(this_cpu,
2194 sched_group_cpus(group));
2196 /* Tally up the load of all CPUs in the group */
2199 for_each_cpu(i, sched_group_cpus(group)) {
2200 /* Bias balancing toward cpus of our domain */
2202 load = source_load(i, load_idx);
2204 load = target_load(i, load_idx);
2209 /* Adjust by relative CPU power of the group */
2210 avg_load = sg_div_cpu_power(group,
2211 avg_load * SCHED_LOAD_SCALE);
2214 this_load = avg_load;
2216 } else if (avg_load < min_load) {
2217 min_load = avg_load;
2220 } while (group = group->next, group != sd->groups);
2222 if (!idlest || 100*this_load < imbalance*min_load)
2228 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2231 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
2233 unsigned long load, min_load = ULONG_MAX;
2237 /* Traverse only the allowed CPUs */
2238 for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {
2239 load = weighted_cpuload(i);
2241 if (load < min_load || (load == min_load && i == this_cpu)) {
2251 * sched_balance_self: balance the current task (running on cpu) in domains
2252 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2255 * Balance, ie. select the least loaded group.
2257 * Returns the target CPU number, or the same CPU if no balancing is needed.
2259 * preempt must be disabled.
2261 static int sched_balance_self(int cpu, int flag)
2263 struct task_struct *t = current;
2264 struct sched_domain *tmp, *sd = NULL;
2266 for_each_domain(cpu, tmp) {
2268 * If power savings logic is enabled for a domain, stop there.
2270 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2272 if (tmp->flags & flag)
2280 struct sched_group *group;
2281 int new_cpu, weight;
2283 if (!(sd->flags & flag)) {
2288 group = find_idlest_group(sd, t, cpu);
2294 new_cpu = find_idlest_cpu(group, t, cpu);
2295 if (new_cpu == -1 || new_cpu == cpu) {
2296 /* Now try balancing at a lower domain level of cpu */
2301 /* Now try balancing at a lower domain level of new_cpu */
2303 weight = cpumask_weight(sched_domain_span(sd));
2305 for_each_domain(cpu, tmp) {
2306 if (weight <= cpumask_weight(sched_domain_span(tmp)))
2308 if (tmp->flags & flag)
2311 /* while loop will break here if sd == NULL */
2317 #endif /* CONFIG_SMP */
2320 * task_oncpu_function_call - call a function on the cpu on which a task runs
2321 * @p: the task to evaluate
2322 * @func: the function to be called
2323 * @info: the function call argument
2325 * Calls the function @func when the task is currently running. This might
2326 * be on the current CPU, which just calls the function directly
2328 void task_oncpu_function_call(struct task_struct *p,
2329 void (*func) (void *info), void *info)
2336 smp_call_function_single(cpu, func, info, 1);
2341 * try_to_wake_up - wake up a thread
2342 * @p: the to-be-woken-up thread
2343 * @state: the mask of task states that can be woken
2344 * @sync: do a synchronous wakeup?
2346 * Put it on the run-queue if it's not already there. The "current"
2347 * thread is always on the run-queue (except when the actual
2348 * re-schedule is in progress), and as such you're allowed to do
2349 * the simpler "current->state = TASK_RUNNING" to mark yourself
2350 * runnable without the overhead of this.
2352 * returns failure only if the task is already active.
2354 static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
2356 int cpu, orig_cpu, this_cpu, success = 0;
2357 unsigned long flags;
2361 if (!sched_feat(SYNC_WAKEUPS))
2365 if (sched_feat(LB_WAKEUP_UPDATE) && !root_task_group_empty()) {
2366 struct sched_domain *sd;
2368 this_cpu = raw_smp_processor_id();
2371 for_each_domain(this_cpu, sd) {
2372 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2381 rq = task_rq_lock(p, &flags);
2382 update_rq_clock(rq);
2383 old_state = p->state;
2384 if (!(old_state & state))
2392 this_cpu = smp_processor_id();
2395 if (unlikely(task_running(rq, p)))
2398 cpu = p->sched_class->select_task_rq(p, sync);
2399 if (cpu != orig_cpu) {
2400 set_task_cpu(p, cpu);
2401 task_rq_unlock(rq, &flags);
2402 /* might preempt at this point */
2403 rq = task_rq_lock(p, &flags);
2404 old_state = p->state;
2405 if (!(old_state & state))
2410 this_cpu = smp_processor_id();
2414 #ifdef CONFIG_SCHEDSTATS
2415 schedstat_inc(rq, ttwu_count);
2416 if (cpu == this_cpu)
2417 schedstat_inc(rq, ttwu_local);
2419 struct sched_domain *sd;
2420 for_each_domain(this_cpu, sd) {
2421 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2422 schedstat_inc(sd, ttwu_wake_remote);
2427 #endif /* CONFIG_SCHEDSTATS */
2430 #endif /* CONFIG_SMP */
2431 schedstat_inc(p, se.nr_wakeups);
2433 schedstat_inc(p, se.nr_wakeups_sync);
2434 if (orig_cpu != cpu)
2435 schedstat_inc(p, se.nr_wakeups_migrate);
2436 if (cpu == this_cpu)
2437 schedstat_inc(p, se.nr_wakeups_local);
2439 schedstat_inc(p, se.nr_wakeups_remote);
2440 activate_task(rq, p, 1);
2444 * Only attribute actual wakeups done by this task.
2446 if (!in_interrupt()) {
2447 struct sched_entity *se = ¤t->se;
2448 u64 sample = se->sum_exec_runtime;
2450 if (se->last_wakeup)
2451 sample -= se->last_wakeup;
2453 sample -= se->start_runtime;
2454 update_avg(&se->avg_wakeup, sample);
2456 se->last_wakeup = se->sum_exec_runtime;
2460 trace_sched_wakeup(rq, p, success);
2461 check_preempt_curr(rq, p, sync);
2463 p->state = TASK_RUNNING;
2465 if (p->sched_class->task_wake_up)
2466 p->sched_class->task_wake_up(rq, p);
2469 task_rq_unlock(rq, &flags);
2474 int wake_up_process(struct task_struct *p)
2476 return try_to_wake_up(p, TASK_ALL, 0);
2478 EXPORT_SYMBOL(wake_up_process);
2480 int wake_up_state(struct task_struct *p, unsigned int state)
2482 return try_to_wake_up(p, state, 0);
2486 * Perform scheduler related setup for a newly forked process p.
2487 * p is forked by current.
2489 * __sched_fork() is basic setup used by init_idle() too:
2491 static void __sched_fork(struct task_struct *p)
2493 p->se.exec_start = 0;
2494 p->se.sum_exec_runtime = 0;
2495 p->se.prev_sum_exec_runtime = 0;
2496 p->se.nr_migrations = 0;
2497 p->se.last_wakeup = 0;
2498 p->se.avg_overlap = 0;
2499 p->se.start_runtime = 0;
2500 p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
2502 #ifdef CONFIG_SCHEDSTATS
2503 p->se.wait_start = 0;
2504 p->se.sum_sleep_runtime = 0;
2505 p->se.sleep_start = 0;
2506 p->se.block_start = 0;
2507 p->se.sleep_max = 0;
2508 p->se.block_max = 0;
2510 p->se.slice_max = 0;
2514 INIT_LIST_HEAD(&p->rt.run_list);
2516 INIT_LIST_HEAD(&p->se.group_node);
2518 #ifdef CONFIG_PREEMPT_NOTIFIERS
2519 INIT_HLIST_HEAD(&p->preempt_notifiers);
2523 * We mark the process as running here, but have not actually
2524 * inserted it onto the runqueue yet. This guarantees that
2525 * nobody will actually run it, and a signal or other external
2526 * event cannot wake it up and insert it on the runqueue either.
2528 p->state = TASK_RUNNING;
2532 * fork()/clone()-time setup:
2534 void sched_fork(struct task_struct *p, int clone_flags)
2536 int cpu = get_cpu();
2541 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
2543 set_task_cpu(p, cpu);
2546 * Make sure we do not leak PI boosting priority to the child:
2548 p->prio = current->normal_prio;
2549 if (!rt_prio(p->prio))
2550 p->sched_class = &fair_sched_class;
2552 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2553 if (likely(sched_info_on()))
2554 memset(&p->sched_info, 0, sizeof(p->sched_info));
2556 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2559 #ifdef CONFIG_PREEMPT
2560 /* Want to start with kernel preemption disabled. */
2561 task_thread_info(p)->preempt_count = 1;
2563 plist_node_init(&p->pushable_tasks, MAX_PRIO);
2569 * wake_up_new_task - wake up a newly created task for the first time.
2571 * This function will do some initial scheduler statistics housekeeping
2572 * that must be done for every newly created context, then puts the task
2573 * on the runqueue and wakes it.
2575 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2577 unsigned long flags;
2580 rq = task_rq_lock(p, &flags);
2581 BUG_ON(p->state != TASK_RUNNING);
2582 update_rq_clock(rq);
2584 p->prio = effective_prio(p);
2586 if (!p->sched_class->task_new || !current->se.on_rq) {
2587 activate_task(rq, p, 0);
2590 * Let the scheduling class do new task startup
2591 * management (if any):
2593 p->sched_class->task_new(rq, p);
2596 trace_sched_wakeup_new(rq, p, 1);
2597 check_preempt_curr(rq, p, 0);
2599 if (p->sched_class->task_wake_up)
2600 p->sched_class->task_wake_up(rq, p);
2602 task_rq_unlock(rq, &flags);
2605 #ifdef CONFIG_PREEMPT_NOTIFIERS
2608 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2609 * @notifier: notifier struct to register
2611 void preempt_notifier_register(struct preempt_notifier *notifier)
2613 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2615 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2618 * preempt_notifier_unregister - no longer interested in preemption notifications
2619 * @notifier: notifier struct to unregister
2621 * This is safe to call from within a preemption notifier.
2623 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2625 hlist_del(¬ifier->link);
2627 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2629 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2631 struct preempt_notifier *notifier;
2632 struct hlist_node *node;
2634 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2635 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2639 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2640 struct task_struct *next)
2642 struct preempt_notifier *notifier;
2643 struct hlist_node *node;
2645 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2646 notifier->ops->sched_out(notifier, next);
2649 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2651 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2656 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2657 struct task_struct *next)
2661 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2664 * prepare_task_switch - prepare to switch tasks
2665 * @rq: the runqueue preparing to switch
2666 * @prev: the current task that is being switched out
2667 * @next: the task we are going to switch to.
2669 * This is called with the rq lock held and interrupts off. It must
2670 * be paired with a subsequent finish_task_switch after the context
2673 * prepare_task_switch sets up locking and calls architecture specific
2677 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2678 struct task_struct *next)
2680 fire_sched_out_preempt_notifiers(prev, next);
2681 prepare_lock_switch(rq, next);
2682 prepare_arch_switch(next);
2686 * finish_task_switch - clean up after a task-switch
2687 * @rq: runqueue associated with task-switch
2688 * @prev: the thread we just switched away from.
2690 * finish_task_switch must be called after the context switch, paired
2691 * with a prepare_task_switch call before the context switch.
2692 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2693 * and do any other architecture-specific cleanup actions.
2695 * Note that we may have delayed dropping an mm in context_switch(). If
2696 * so, we finish that here outside of the runqueue lock. (Doing it
2697 * with the lock held can cause deadlocks; see schedule() for
2700 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2701 __releases(rq->lock)
2703 struct mm_struct *mm = rq->prev_mm;
2706 int post_schedule = 0;
2708 if (current->sched_class->needs_post_schedule)
2709 post_schedule = current->sched_class->needs_post_schedule(rq);
2715 * A task struct has one reference for the use as "current".
2716 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2717 * schedule one last time. The schedule call will never return, and
2718 * the scheduled task must drop that reference.
2719 * The test for TASK_DEAD must occur while the runqueue locks are
2720 * still held, otherwise prev could be scheduled on another cpu, die
2721 * there before we look at prev->state, and then the reference would
2723 * Manfred Spraul <manfred@colorfullife.com>
2725 prev_state = prev->state;
2726 finish_arch_switch(prev);
2727 perf_counter_task_sched_in(current, cpu_of(rq));
2728 finish_lock_switch(rq, prev);
2731 current->sched_class->post_schedule(rq);
2734 fire_sched_in_preempt_notifiers(current);
2737 if (unlikely(prev_state == TASK_DEAD)) {
2739 * Remove function-return probe instances associated with this
2740 * task and put them back on the free list.
2742 kprobe_flush_task(prev);
2743 put_task_struct(prev);
2748 * schedule_tail - first thing a freshly forked thread must call.
2749 * @prev: the thread we just switched away from.
2751 asmlinkage void schedule_tail(struct task_struct *prev)
2752 __releases(rq->lock)
2754 struct rq *rq = this_rq();
2756 finish_task_switch(rq, prev);
2757 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2758 /* In this case, finish_task_switch does not reenable preemption */
2761 if (current->set_child_tid)
2762 put_user(task_pid_vnr(current), current->set_child_tid);
2766 * context_switch - switch to the new MM and the new
2767 * thread's register state.
2770 context_switch(struct rq *rq, struct task_struct *prev,
2771 struct task_struct *next)
2773 struct mm_struct *mm, *oldmm;
2775 prepare_task_switch(rq, prev, next);
2776 trace_sched_switch(rq, prev, next);
2778 oldmm = prev->active_mm;
2780 * For paravirt, this is coupled with an exit in switch_to to
2781 * combine the page table reload and the switch backend into
2784 arch_enter_lazy_cpu_mode();
2786 if (unlikely(!mm)) {
2787 next->active_mm = oldmm;
2788 atomic_inc(&oldmm->mm_count);
2789 enter_lazy_tlb(oldmm, next);
2791 switch_mm(oldmm, mm, next);
2793 if (unlikely(!prev->mm)) {
2794 prev->active_mm = NULL;
2795 rq->prev_mm = oldmm;
2798 * Since the runqueue lock will be released by the next
2799 * task (which is an invalid locking op but in the case
2800 * of the scheduler it's an obvious special-case), so we
2801 * do an early lockdep release here:
2803 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2804 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2807 /* Here we just switch the register state and the stack. */
2808 switch_to(prev, next, prev);
2812 * this_rq must be evaluated again because prev may have moved
2813 * CPUs since it called schedule(), thus the 'rq' on its stack
2814 * frame will be invalid.
2816 finish_task_switch(this_rq(), prev);
2820 * nr_running, nr_uninterruptible and nr_context_switches:
2822 * externally visible scheduler statistics: current number of runnable
2823 * threads, current number of uninterruptible-sleeping threads, total
2824 * number of context switches performed since bootup.
2826 unsigned long nr_running(void)
2828 unsigned long i, sum = 0;
2830 for_each_online_cpu(i)
2831 sum += cpu_rq(i)->nr_running;
2836 unsigned long nr_uninterruptible(void)
2838 unsigned long i, sum = 0;
2840 for_each_possible_cpu(i)
2841 sum += cpu_rq(i)->nr_uninterruptible;
2844 * Since we read the counters lockless, it might be slightly
2845 * inaccurate. Do not allow it to go below zero though:
2847 if (unlikely((long)sum < 0))
2853 unsigned long long nr_context_switches(void)
2856 unsigned long long sum = 0;
2858 for_each_possible_cpu(i)
2859 sum += cpu_rq(i)->nr_switches;
2864 unsigned long nr_iowait(void)
2866 unsigned long i, sum = 0;
2868 for_each_possible_cpu(i)
2869 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2874 unsigned long nr_active(void)
2876 unsigned long i, running = 0, uninterruptible = 0;
2878 for_each_online_cpu(i) {
2879 running += cpu_rq(i)->nr_running;
2880 uninterruptible += cpu_rq(i)->nr_uninterruptible;
2883 if (unlikely((long)uninterruptible < 0))
2884 uninterruptible = 0;
2886 return running + uninterruptible;
2890 * Externally visible per-cpu scheduler statistics:
2891 * cpu_nr_migrations(cpu) - number of migrations into that cpu
2893 u64 cpu_nr_migrations(int cpu)
2895 return cpu_rq(cpu)->nr_migrations_in;
2899 * Update rq->cpu_load[] statistics. This function is usually called every
2900 * scheduler tick (TICK_NSEC).
2902 static void update_cpu_load(struct rq *this_rq)
2904 unsigned long this_load = this_rq->load.weight;
2907 this_rq->nr_load_updates++;
2909 /* Update our load: */
2910 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2911 unsigned long old_load, new_load;
2913 /* scale is effectively 1 << i now, and >> i divides by scale */
2915 old_load = this_rq->cpu_load[i];
2916 new_load = this_load;
2918 * Round up the averaging division if load is increasing. This
2919 * prevents us from getting stuck on 9 if the load is 10, for
2922 if (new_load > old_load)
2923 new_load += scale-1;
2924 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
2931 * double_rq_lock - safely lock two runqueues
2933 * Note this does not disable interrupts like task_rq_lock,
2934 * you need to do so manually before calling.
2936 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
2937 __acquires(rq1->lock)
2938 __acquires(rq2->lock)
2940 BUG_ON(!irqs_disabled());
2942 spin_lock(&rq1->lock);
2943 __acquire(rq2->lock); /* Fake it out ;) */
2946 spin_lock(&rq1->lock);
2947 spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
2949 spin_lock(&rq2->lock);
2950 spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
2953 update_rq_clock(rq1);
2954 update_rq_clock(rq2);
2958 * double_rq_unlock - safely unlock two runqueues
2960 * Note this does not restore interrupts like task_rq_unlock,
2961 * you need to do so manually after calling.
2963 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
2964 __releases(rq1->lock)
2965 __releases(rq2->lock)
2967 spin_unlock(&rq1->lock);
2969 spin_unlock(&rq2->lock);
2971 __release(rq2->lock);
2975 * If dest_cpu is allowed for this process, migrate the task to it.
2976 * This is accomplished by forcing the cpu_allowed mask to only
2977 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2978 * the cpu_allowed mask is restored.
2980 static void sched_migrate_task(struct task_struct *p, int dest_cpu)
2982 struct migration_req req;
2983 unsigned long flags;
2986 rq = task_rq_lock(p, &flags);
2987 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)
2988 || unlikely(!cpu_active(dest_cpu)))
2991 /* force the process onto the specified CPU */
2992 if (migrate_task(p, dest_cpu, &req)) {
2993 /* Need to wait for migration thread (might exit: take ref). */
2994 struct task_struct *mt = rq->migration_thread;
2996 get_task_struct(mt);
2997 task_rq_unlock(rq, &flags);
2998 wake_up_process(mt);
2999 put_task_struct(mt);
3000 wait_for_completion(&req.done);
3005 task_rq_unlock(rq, &flags);
3009 * sched_exec - execve() is a valuable balancing opportunity, because at
3010 * this point the task has the smallest effective memory and cache footprint.
3012 void sched_exec(void)
3014 int new_cpu, this_cpu = get_cpu();
3015 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
3017 if (new_cpu != this_cpu)
3018 sched_migrate_task(current, new_cpu);
3022 * pull_task - move a task from a remote runqueue to the local runqueue.
3023 * Both runqueues must be locked.
3025 static void pull_task(struct rq *src_rq, struct task_struct *p,
3026 struct rq *this_rq, int this_cpu)
3028 deactivate_task(src_rq, p, 0);
3029 set_task_cpu(p, this_cpu);
3030 activate_task(this_rq, p, 0);
3032 * Note that idle threads have a prio of MAX_PRIO, for this test
3033 * to be always true for them.
3035 check_preempt_curr(this_rq, p, 0);
3039 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3042 int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
3043 struct sched_domain *sd, enum cpu_idle_type idle,
3046 int tsk_cache_hot = 0;
3048 * We do not migrate tasks that are:
3049 * 1) running (obviously), or
3050 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3051 * 3) are cache-hot on their current CPU.
3053 if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) {
3054 schedstat_inc(p, se.nr_failed_migrations_affine);
3059 if (task_running(rq, p)) {
3060 schedstat_inc(p, se.nr_failed_migrations_running);
3065 * Aggressive migration if:
3066 * 1) task is cache cold, or
3067 * 2) too many balance attempts have failed.
3070 tsk_cache_hot = task_hot(p, rq->clock, sd);
3071 if (!tsk_cache_hot ||
3072 sd->nr_balance_failed > sd->cache_nice_tries) {
3073 #ifdef CONFIG_SCHEDSTATS
3074 if (tsk_cache_hot) {
3075 schedstat_inc(sd, lb_hot_gained[idle]);
3076 schedstat_inc(p, se.nr_forced_migrations);
3082 if (tsk_cache_hot) {
3083 schedstat_inc(p, se.nr_failed_migrations_hot);
3089 static unsigned long
3090 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3091 unsigned long max_load_move, struct sched_domain *sd,
3092 enum cpu_idle_type idle, int *all_pinned,
3093 int *this_best_prio, struct rq_iterator *iterator)
3095 int loops = 0, pulled = 0, pinned = 0;
3096 struct task_struct *p;
3097 long rem_load_move = max_load_move;
3099 if (max_load_move == 0)
3105 * Start the load-balancing iterator:
3107 p = iterator->start(iterator->arg);
3109 if (!p || loops++ > sysctl_sched_nr_migrate)
3112 if ((p->se.load.weight >> 1) > rem_load_move ||
3113 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3114 p = iterator->next(iterator->arg);
3118 pull_task(busiest, p, this_rq, this_cpu);
3120 rem_load_move -= p->se.load.weight;
3122 #ifdef CONFIG_PREEMPT
3124 * NEWIDLE balancing is a source of latency, so preemptible kernels
3125 * will stop after the first task is pulled to minimize the critical
3128 if (idle == CPU_NEWLY_IDLE)
3133 * We only want to steal up to the prescribed amount of weighted load.
3135 if (rem_load_move > 0) {
3136 if (p->prio < *this_best_prio)
3137 *this_best_prio = p->prio;
3138 p = iterator->next(iterator->arg);
3143 * Right now, this is one of only two places pull_task() is called,
3144 * so we can safely collect pull_task() stats here rather than
3145 * inside pull_task().
3147 schedstat_add(sd, lb_gained[idle], pulled);
3150 *all_pinned = pinned;
3152 return max_load_move - rem_load_move;
3156 * move_tasks tries to move up to max_load_move weighted load from busiest to
3157 * this_rq, as part of a balancing operation within domain "sd".
3158 * Returns 1 if successful and 0 otherwise.
3160 * Called with both runqueues locked.
3162 static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3163 unsigned long max_load_move,
3164 struct sched_domain *sd, enum cpu_idle_type idle,
3167 const struct sched_class *class = sched_class_highest;
3168 unsigned long total_load_moved = 0;
3169 int this_best_prio = this_rq->curr->prio;
3173 class->load_balance(this_rq, this_cpu, busiest,
3174 max_load_move - total_load_moved,
3175 sd, idle, all_pinned, &this_best_prio);
3176 class = class->next;
3178 #ifdef CONFIG_PREEMPT
3180 * NEWIDLE balancing is a source of latency, so preemptible
3181 * kernels will stop after the first task is pulled to minimize
3182 * the critical section.
3184 if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
3187 } while (class && max_load_move > total_load_moved);
3189 return total_load_moved > 0;
3193 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3194 struct sched_domain *sd, enum cpu_idle_type idle,
3195 struct rq_iterator *iterator)
3197 struct task_struct *p = iterator->start(iterator->arg);
3201 if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3202 pull_task(busiest, p, this_rq, this_cpu);
3204 * Right now, this is only the second place pull_task()
3205 * is called, so we can safely collect pull_task()
3206 * stats here rather than inside pull_task().
3208 schedstat_inc(sd, lb_gained[idle]);
3212 p = iterator->next(iterator->arg);
3219 * move_one_task tries to move exactly one task from busiest to this_rq, as
3220 * part of active balancing operations within "domain".
3221 * Returns 1 if successful and 0 otherwise.
3223 * Called with both runqueues locked.
3225 static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3226 struct sched_domain *sd, enum cpu_idle_type idle)
3228 const struct sched_class *class;
3230 for (class = sched_class_highest; class; class = class->next)
3231 if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
3236 /********** Helpers for find_busiest_group ************************/
3238 * sd_lb_stats - Structure to store the statistics of a sched_domain
3239 * during load balancing.
3241 struct sd_lb_stats {
3242 struct sched_group *busiest; /* Busiest group in this sd */
3243 struct sched_group *this; /* Local group in this sd */
3244 unsigned long total_load; /* Total load of all groups in sd */
3245 unsigned long total_pwr; /* Total power of all groups in sd */
3246 unsigned long avg_load; /* Average load across all groups in sd */
3248 /** Statistics of this group */
3249 unsigned long this_load;
3250 unsigned long this_load_per_task;
3251 unsigned long this_nr_running;
3253 /* Statistics of the busiest group */
3254 unsigned long max_load;
3255 unsigned long busiest_load_per_task;
3256 unsigned long busiest_nr_running;
3258 int group_imb; /* Is there imbalance in this sd */
3259 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3260 int power_savings_balance; /* Is powersave balance needed for this sd */
3261 struct sched_group *group_min; /* Least loaded group in sd */
3262 struct sched_group *group_leader; /* Group which relieves group_min */
3263 unsigned long min_load_per_task; /* load_per_task in group_min */
3264 unsigned long leader_nr_running; /* Nr running of group_leader */
3265 unsigned long min_nr_running; /* Nr running of group_min */
3270 * sg_lb_stats - stats of a sched_group required for load_balancing
3272 struct sg_lb_stats {
3273 unsigned long avg_load; /*Avg load across the CPUs of the group */
3274 unsigned long group_load; /* Total load over the CPUs of the group */
3275 unsigned long sum_nr_running; /* Nr tasks running in the group */
3276 unsigned long sum_weighted_load; /* Weighted load of group's tasks */
3277 unsigned long group_capacity;
3278 int group_imb; /* Is there an imbalance in the group ? */
3282 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3283 * @group: The group whose first cpu is to be returned.
3285 static inline unsigned int group_first_cpu(struct sched_group *group)
3287 return cpumask_first(sched_group_cpus(group));
3291 * get_sd_load_idx - Obtain the load index for a given sched domain.
3292 * @sd: The sched_domain whose load_idx is to be obtained.
3293 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3295 static inline int get_sd_load_idx(struct sched_domain *sd,
3296 enum cpu_idle_type idle)
3302 load_idx = sd->busy_idx;
3305 case CPU_NEWLY_IDLE:
3306 load_idx = sd->newidle_idx;
3309 load_idx = sd->idle_idx;
3317 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3319 * init_sd_power_savings_stats - Initialize power savings statistics for
3320 * the given sched_domain, during load balancing.
3322 * @sd: Sched domain whose power-savings statistics are to be initialized.
3323 * @sds: Variable containing the statistics for sd.
3324 * @idle: Idle status of the CPU at which we're performing load-balancing.
3326 static inline void init_sd_power_savings_stats(struct sched_domain *sd,
3327 struct sd_lb_stats *sds, enum cpu_idle_type idle)
3330 * Busy processors will not participate in power savings
3333 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
3334 sds->power_savings_balance = 0;
3336 sds->power_savings_balance = 1;
3337 sds->min_nr_running = ULONG_MAX;
3338 sds->leader_nr_running = 0;
3343 * update_sd_power_savings_stats - Update the power saving stats for a
3344 * sched_domain while performing load balancing.
3346 * @group: sched_group belonging to the sched_domain under consideration.
3347 * @sds: Variable containing the statistics of the sched_domain
3348 * @local_group: Does group contain the CPU for which we're performing
3350 * @sgs: Variable containing the statistics of the group.
3352 static inline void update_sd_power_savings_stats(struct sched_group *group,
3353 struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
3356 if (!sds->power_savings_balance)
3360 * If the local group is idle or completely loaded
3361 * no need to do power savings balance at this domain
3363 if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
3364 !sds->this_nr_running))
3365 sds->power_savings_balance = 0;
3368 * If a group is already running at full capacity or idle,
3369 * don't include that group in power savings calculations
3371 if (!sds->power_savings_balance ||
3372 sgs->sum_nr_running >= sgs->group_capacity ||
3373 !sgs->sum_nr_running)
3377 * Calculate the group which has the least non-idle load.
3378 * This is the group from where we need to pick up the load
3381 if ((sgs->sum_nr_running < sds->min_nr_running) ||
3382 (sgs->sum_nr_running == sds->min_nr_running &&
3383 group_first_cpu(group) > group_first_cpu(sds->group_min))) {
3384 sds->group_min = group;
3385 sds->min_nr_running = sgs->sum_nr_running;
3386 sds->min_load_per_task = sgs->sum_weighted_load /
3387 sgs->sum_nr_running;
3391 * Calculate the group which is almost near its
3392 * capacity but still has some space to pick up some load
3393 * from other group and save more power
3395 if (sgs->sum_nr_running > sgs->group_capacity - 1)
3398 if (sgs->sum_nr_running > sds->leader_nr_running ||
3399 (sgs->sum_nr_running == sds->leader_nr_running &&
3400 group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
3401 sds->group_leader = group;
3402 sds->leader_nr_running = sgs->sum_nr_running;
3407 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3408 * @sds: Variable containing the statistics of the sched_domain
3409 * under consideration.
3410 * @this_cpu: Cpu at which we're currently performing load-balancing.
3411 * @imbalance: Variable to store the imbalance.
3414 * Check if we have potential to perform some power-savings balance.
3415 * If yes, set the busiest group to be the least loaded group in the
3416 * sched_domain, so that it's CPUs can be put to idle.
3418 * Returns 1 if there is potential to perform power-savings balance.
3421 static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
3422 int this_cpu, unsigned long *imbalance)
3424 if (!sds->power_savings_balance)
3427 if (sds->this != sds->group_leader ||
3428 sds->group_leader == sds->group_min)
3431 *imbalance = sds->min_load_per_task;
3432 sds->busiest = sds->group_min;
3434 if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
3435 cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
3436 group_first_cpu(sds->group_leader);
3442 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3443 static inline void init_sd_power_savings_stats(struct sched_domain *sd,
3444 struct sd_lb_stats *sds, enum cpu_idle_type idle)
3449 static inline void update_sd_power_savings_stats(struct sched_group *group,
3450 struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
3455 static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
3456 int this_cpu, unsigned long *imbalance)
3460 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3464 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3465 * @group: sched_group whose statistics are to be updated.
3466 * @this_cpu: Cpu for which load balance is currently performed.
3467 * @idle: Idle status of this_cpu
3468 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3469 * @sd_idle: Idle status of the sched_domain containing group.
3470 * @local_group: Does group contain this_cpu.
3471 * @cpus: Set of cpus considered for load balancing.
3472 * @balance: Should we balance.
3473 * @sgs: variable to hold the statistics for this group.
3475 static inline void update_sg_lb_stats(struct sched_group *group, int this_cpu,
3476 enum cpu_idle_type idle, int load_idx, int *sd_idle,
3477 int local_group, const struct cpumask *cpus,
3478 int *balance, struct sg_lb_stats *sgs)
3480 unsigned long load, max_cpu_load, min_cpu_load;
3482 unsigned int balance_cpu = -1, first_idle_cpu = 0;
3483 unsigned long sum_avg_load_per_task;
3484 unsigned long avg_load_per_task;
3487 balance_cpu = group_first_cpu(group);
3489 /* Tally up the load of all CPUs in the group */
3490 sum_avg_load_per_task = avg_load_per_task = 0;
3492 min_cpu_load = ~0UL;
3494 for_each_cpu_and(i, sched_group_cpus(group), cpus) {
3495 struct rq *rq = cpu_rq(i);
3497 if (*sd_idle && rq->nr_running)
3500 /* Bias balancing toward cpus of our domain */
3502 if (idle_cpu(i) && !first_idle_cpu) {
3507 load = target_load(i, load_idx);
3509 load = source_load(i, load_idx);
3510 if (load > max_cpu_load)
3511 max_cpu_load = load;
3512 if (min_cpu_load > load)
3513 min_cpu_load = load;
3516 sgs->group_load += load;
3517 sgs->sum_nr_running += rq->nr_running;
3518 sgs->sum_weighted_load += weighted_cpuload(i);
3520 sum_avg_load_per_task += cpu_avg_load_per_task(i);
3524 * First idle cpu or the first cpu(busiest) in this sched group
3525 * is eligible for doing load balancing at this and above
3526 * domains. In the newly idle case, we will allow all the cpu's
3527 * to do the newly idle load balance.
3529 if (idle != CPU_NEWLY_IDLE && local_group &&
3530 balance_cpu != this_cpu && balance) {
3535 /* Adjust by relative CPU power of the group */
3536 sgs->avg_load = sg_div_cpu_power(group,
3537 sgs->group_load * SCHED_LOAD_SCALE);
3541 * Consider the group unbalanced when the imbalance is larger
3542 * than the average weight of two tasks.
3544 * APZ: with cgroup the avg task weight can vary wildly and
3545 * might not be a suitable number - should we keep a
3546 * normalized nr_running number somewhere that negates
3549 avg_load_per_task = sg_div_cpu_power(group,
3550 sum_avg_load_per_task * SCHED_LOAD_SCALE);
3552 if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
3555 sgs->group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
3560 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3561 * @sd: sched_domain whose statistics are to be updated.
3562 * @this_cpu: Cpu for which load balance is currently performed.
3563 * @idle: Idle status of this_cpu
3564 * @sd_idle: Idle status of the sched_domain containing group.
3565 * @cpus: Set of cpus considered for load balancing.
3566 * @balance: Should we balance.
3567 * @sds: variable to hold the statistics for this sched_domain.
3569 static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
3570 enum cpu_idle_type idle, int *sd_idle,
3571 const struct cpumask *cpus, int *balance,
3572 struct sd_lb_stats *sds)
3574 struct sched_group *group = sd->groups;
3575 struct sg_lb_stats sgs;
3578 init_sd_power_savings_stats(sd, sds, idle);
3579 load_idx = get_sd_load_idx(sd, idle);
3584 local_group = cpumask_test_cpu(this_cpu,
3585 sched_group_cpus(group));
3586 memset(&sgs, 0, sizeof(sgs));
3587 update_sg_lb_stats(group, this_cpu, idle, load_idx, sd_idle,
3588 local_group, cpus, balance, &sgs);
3590 if (local_group && balance && !(*balance))
3593 sds->total_load += sgs.group_load;
3594 sds->total_pwr += group->__cpu_power;
3597 sds->this_load = sgs.avg_load;
3599 sds->this_nr_running = sgs.sum_nr_running;
3600 sds->this_load_per_task = sgs.sum_weighted_load;
3601 } else if (sgs.avg_load > sds->max_load &&
3602 (sgs.sum_nr_running > sgs.group_capacity ||
3604 sds->max_load = sgs.avg_load;
3605 sds->busiest = group;
3606 sds->busiest_nr_running = sgs.sum_nr_running;
3607 sds->busiest_load_per_task = sgs.sum_weighted_load;
3608 sds->group_imb = sgs.group_imb;
3611 update_sd_power_savings_stats(group, sds, local_group, &sgs);
3612 group = group->next;
3613 } while (group != sd->groups);
3618 * fix_small_imbalance - Calculate the minor imbalance that exists
3619 * amongst the groups of a sched_domain, during
3621 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3622 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3623 * @imbalance: Variable to store the imbalance.
3625 static inline void fix_small_imbalance(struct sd_lb_stats *sds,
3626 int this_cpu, unsigned long *imbalance)
3628 unsigned long tmp, pwr_now = 0, pwr_move = 0;
3629 unsigned int imbn = 2;
3631 if (sds->this_nr_running) {
3632 sds->this_load_per_task /= sds->this_nr_running;
3633 if (sds->busiest_load_per_task >
3634 sds->this_load_per_task)
3637 sds->this_load_per_task =
3638 cpu_avg_load_per_task(this_cpu);
3640 if (sds->max_load - sds->this_load + sds->busiest_load_per_task >=
3641 sds->busiest_load_per_task * imbn) {
3642 *imbalance = sds->busiest_load_per_task;
3647 * OK, we don't have enough imbalance to justify moving tasks,
3648 * however we may be able to increase total CPU power used by
3652 pwr_now += sds->busiest->__cpu_power *
3653 min(sds->busiest_load_per_task, sds->max_load);
3654 pwr_now += sds->this->__cpu_power *
3655 min(sds->this_load_per_task, sds->this_load);
3656 pwr_now /= SCHED_LOAD_SCALE;
3658 /* Amount of load we'd subtract */
3659 tmp = sg_div_cpu_power(sds->busiest,
3660 sds->busiest_load_per_task * SCHED_LOAD_SCALE);
3661 if (sds->max_load > tmp)
3662 pwr_move += sds->busiest->__cpu_power *
3663 min(sds->busiest_load_per_task, sds->max_load - tmp);
3665 /* Amount of load we'd add */
3666 if (sds->max_load * sds->busiest->__cpu_power <
3667 sds->busiest_load_per_task * SCHED_LOAD_SCALE)
3668 tmp = sg_div_cpu_power(sds->this,
3669 sds->max_load * sds->busiest->__cpu_power);
3671 tmp = sg_div_cpu_power(sds->this,
3672 sds->busiest_load_per_task * SCHED_LOAD_SCALE);
3673 pwr_move += sds->this->__cpu_power *
3674 min(sds->this_load_per_task, sds->this_load + tmp);
3675 pwr_move /= SCHED_LOAD_SCALE;
3677 /* Move if we gain throughput */
3678 if (pwr_move > pwr_now)
3679 *imbalance = sds->busiest_load_per_task;
3683 * calculate_imbalance - Calculate the amount of imbalance present within the
3684 * groups of a given sched_domain during load balance.
3685 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3686 * @this_cpu: Cpu for which currently load balance is being performed.
3687 * @imbalance: The variable to store the imbalance.
3689 static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
3690 unsigned long *imbalance)
3692 unsigned long max_pull;
3694 * In the presence of smp nice balancing, certain scenarios can have
3695 * max load less than avg load(as we skip the groups at or below
3696 * its cpu_power, while calculating max_load..)
3698 if (sds->max_load < sds->avg_load) {
3700 return fix_small_imbalance(sds, this_cpu, imbalance);
3703 /* Don't want to pull so many tasks that a group would go idle */
3704 max_pull = min(sds->max_load - sds->avg_load,
3705 sds->max_load - sds->busiest_load_per_task);
3707 /* How much load to actually move to equalise the imbalance */
3708 *imbalance = min(max_pull * sds->busiest->__cpu_power,
3709 (sds->avg_load - sds->this_load) * sds->this->__cpu_power)
3713 * if *imbalance is less than the average load per runnable task
3714 * there is no gaurantee that any tasks will be moved so we'll have
3715 * a think about bumping its value to force at least one task to be
3718 if (*imbalance < sds->busiest_load_per_task)
3719 return fix_small_imbalance(sds, this_cpu, imbalance);
3722 /******* find_busiest_group() helpers end here *********************/
3725 * find_busiest_group - Returns the busiest group within the sched_domain
3726 * if there is an imbalance. If there isn't an imbalance, and
3727 * the user has opted for power-savings, it returns a group whose
3728 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3729 * such a group exists.
3731 * Also calculates the amount of weighted load which should be moved
3732 * to restore balance.
3734 * @sd: The sched_domain whose busiest group is to be returned.
3735 * @this_cpu: The cpu for which load balancing is currently being performed.
3736 * @imbalance: Variable which stores amount of weighted load which should
3737 * be moved to restore balance/put a group to idle.
3738 * @idle: The idle status of this_cpu.
3739 * @sd_idle: The idleness of sd
3740 * @cpus: The set of CPUs under consideration for load-balancing.
3741 * @balance: Pointer to a variable indicating if this_cpu
3742 * is the appropriate cpu to perform load balancing at this_level.
3744 * Returns: - the busiest group if imbalance exists.
3745 * - If no imbalance and user has opted for power-savings balance,
3746 * return the least loaded group whose CPUs can be
3747 * put to idle by rebalancing its tasks onto our group.
3749 static struct sched_group *
3750 find_busiest_group(struct sched_domain *sd, int this_cpu,
3751 unsigned long *imbalance, enum cpu_idle_type idle,
3752 int *sd_idle, const struct cpumask *cpus, int *balance)
3754 struct sd_lb_stats sds;
3756 memset(&sds, 0, sizeof(sds));
3759 * Compute the various statistics relavent for load balancing at
3762 update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus,
3765 /* Cases where imbalance does not exist from POV of this_cpu */
3766 /* 1) this_cpu is not the appropriate cpu to perform load balancing
3768 * 2) There is no busy sibling group to pull from.
3769 * 3) This group is the busiest group.
3770 * 4) This group is more busy than the avg busieness at this
3772 * 5) The imbalance is within the specified limit.
3773 * 6) Any rebalance would lead to ping-pong
3775 if (balance && !(*balance))
3778 if (!sds.busiest || sds.busiest_nr_running == 0)
3781 if (sds.this_load >= sds.max_load)
3784 sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
3786 if (sds.this_load >= sds.avg_load)
3789 if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
3792 sds.busiest_load_per_task /= sds.busiest_nr_running;
3794 sds.busiest_load_per_task =
3795 min(sds.busiest_load_per_task, sds.avg_load);
3798 * We're trying to get all the cpus to the average_load, so we don't
3799 * want to push ourselves above the average load, nor do we wish to
3800 * reduce the max loaded cpu below the average load, as either of these
3801 * actions would just result in more rebalancing later, and ping-pong
3802 * tasks around. Thus we look for the minimum possible imbalance.
3803 * Negative imbalances (*we* are more loaded than anyone else) will
3804 * be counted as no imbalance for these purposes -- we can't fix that
3805 * by pulling tasks to us. Be careful of negative numbers as they'll
3806 * appear as very large values with unsigned longs.
3808 if (sds.max_load <= sds.busiest_load_per_task)
3811 /* Looks like there is an imbalance. Compute it */
3812 calculate_imbalance(&sds, this_cpu, imbalance);
3817 * There is no obvious imbalance. But check if we can do some balancing
3820 if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
3828 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3831 find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
3832 unsigned long imbalance, const struct cpumask *cpus)
3834 struct rq *busiest = NULL, *rq;
3835 unsigned long max_load = 0;
3838 for_each_cpu(i, sched_group_cpus(group)) {
3841 if (!cpumask_test_cpu(i, cpus))
3845 wl = weighted_cpuload(i);
3847 if (rq->nr_running == 1 && wl > imbalance)
3850 if (wl > max_load) {
3860 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3861 * so long as it is large enough.
3863 #define MAX_PINNED_INTERVAL 512
3865 /* Working cpumask for load_balance and load_balance_newidle. */
3866 static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
3869 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3870 * tasks if there is an imbalance.
3872 static int load_balance(int this_cpu, struct rq *this_rq,
3873 struct sched_domain *sd, enum cpu_idle_type idle,
3876 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
3877 struct sched_group *group;
3878 unsigned long imbalance;
3880 unsigned long flags;
3881 struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
3883 cpumask_setall(cpus);
3886 * When power savings policy is enabled for the parent domain, idle
3887 * sibling can pick up load irrespective of busy siblings. In this case,
3888 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3889 * portraying it as CPU_NOT_IDLE.
3891 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
3892 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3895 schedstat_inc(sd, lb_count[idle]);
3899 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
3906 schedstat_inc(sd, lb_nobusyg[idle]);
3910 busiest = find_busiest_queue(group, idle, imbalance, cpus);
3912 schedstat_inc(sd, lb_nobusyq[idle]);
3916 BUG_ON(busiest == this_rq);
3918 schedstat_add(sd, lb_imbalance[idle], imbalance);
3921 if (busiest->nr_running > 1) {
3923 * Attempt to move tasks. If find_busiest_group has found
3924 * an imbalance but busiest->nr_running <= 1, the group is
3925 * still unbalanced. ld_moved simply stays zero, so it is
3926 * correctly treated as an imbalance.
3928 local_irq_save(flags);
3929 double_rq_lock(this_rq, busiest);
3930 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3931 imbalance, sd, idle, &all_pinned);
3932 double_rq_unlock(this_rq, busiest);
3933 local_irq_restore(flags);
3936 * some other cpu did the load balance for us.
3938 if (ld_moved && this_cpu != smp_processor_id())
3939 resched_cpu(this_cpu);
3941 /* All tasks on this runqueue were pinned by CPU affinity */
3942 if (unlikely(all_pinned)) {
3943 cpumask_clear_cpu(cpu_of(busiest), cpus);
3944 if (!cpumask_empty(cpus))
3951 schedstat_inc(sd, lb_failed[idle]);
3952 sd->nr_balance_failed++;
3954 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
3956 spin_lock_irqsave(&busiest->lock, flags);
3958 /* don't kick the migration_thread, if the curr
3959 * task on busiest cpu can't be moved to this_cpu
3961 if (!cpumask_test_cpu(this_cpu,
3962 &busiest->curr->cpus_allowed)) {
3963 spin_unlock_irqrestore(&busiest->lock, flags);
3965 goto out_one_pinned;
3968 if (!busiest->active_balance) {
3969 busiest->active_balance = 1;
3970 busiest->push_cpu = this_cpu;
3973 spin_unlock_irqrestore(&busiest->lock, flags);
3975 wake_up_process(busiest->migration_thread);
3978 * We've kicked active balancing, reset the failure
3981 sd->nr_balance_failed = sd->cache_nice_tries+1;
3984 sd->nr_balance_failed = 0;
3986 if (likely(!active_balance)) {
3987 /* We were unbalanced, so reset the balancing interval */
3988 sd->balance_interval = sd->min_interval;
3991 * If we've begun active balancing, start to back off. This
3992 * case may not be covered by the all_pinned logic if there
3993 * is only 1 task on the busy runqueue (because we don't call
3996 if (sd->balance_interval < sd->max_interval)
3997 sd->balance_interval *= 2;
4000 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4001 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4007 schedstat_inc(sd, lb_balanced[idle]);
4009 sd->nr_balance_failed = 0;
4012 /* tune up the balancing interval */
4013 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
4014 (sd->balance_interval < sd->max_interval))
4015 sd->balance_interval *= 2;
4017 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4018 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4029 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4030 * tasks if there is an imbalance.
4032 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4033 * this_rq is locked.
4036 load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
4038 struct sched_group *group;
4039 struct rq *busiest = NULL;
4040 unsigned long imbalance;
4044 struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
4046 cpumask_setall(cpus);
4049 * When power savings policy is enabled for the parent domain, idle
4050 * sibling can pick up load irrespective of busy siblings. In this case,
4051 * let the state of idle sibling percolate up as IDLE, instead of
4052 * portraying it as CPU_NOT_IDLE.
4054 if (sd->flags & SD_SHARE_CPUPOWER &&
4055 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4058 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
4060 update_shares_locked(this_rq, sd);
4061 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
4062 &sd_idle, cpus, NULL);
4064 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
4068 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
4070 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
4074 BUG_ON(busiest == this_rq);
4076 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
4079 if (busiest->nr_running > 1) {
4080 /* Attempt to move tasks */
4081 double_lock_balance(this_rq, busiest);
4082 /* this_rq->clock is already updated */
4083 update_rq_clock(busiest);
4084 ld_moved = move_tasks(this_rq, this_cpu, busiest,
4085 imbalance, sd, CPU_NEWLY_IDLE,
4087 double_unlock_balance(this_rq, busiest);
4089 if (unlikely(all_pinned)) {
4090 cpumask_clear_cpu(cpu_of(busiest), cpus);
4091 if (!cpumask_empty(cpus))
4097 int active_balance = 0;
4099 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
4100 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4101 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4104 if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
4107 if (sd->nr_balance_failed++ < 2)
4111 * The only task running in a non-idle cpu can be moved to this
4112 * cpu in an attempt to completely freeup the other CPU
4113 * package. The same method used to move task in load_balance()
4114 * have been extended for load_balance_newidle() to speedup
4115 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4117 * The package power saving logic comes from
4118 * find_busiest_group(). If there are no imbalance, then
4119 * f_b_g() will return NULL. However when sched_mc={1,2} then
4120 * f_b_g() will select a group from which a running task may be
4121 * pulled to this cpu in order to make the other package idle.
4122 * If there is no opportunity to make a package idle and if
4123 * there are no imbalance, then f_b_g() will return NULL and no
4124 * action will be taken in load_balance_newidle().
4126 * Under normal task pull operation due to imbalance, there
4127 * will be more than one task in the source run queue and
4128 * move_tasks() will succeed. ld_moved will be true and this
4129 * active balance code will not be triggered.
4132 /* Lock busiest in correct order while this_rq is held */
4133 double_lock_balance(this_rq, busiest);
4136 * don't kick the migration_thread, if the curr
4137 * task on busiest cpu can't be moved to this_cpu
4139 if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) {
4140 double_unlock_balance(this_rq, busiest);
4145 if (!busiest->active_balance) {
4146 busiest->active_balance = 1;
4147 busiest->push_cpu = this_cpu;
4151 double_unlock_balance(this_rq, busiest);
4153 * Should not call ttwu while holding a rq->lock
4155 spin_unlock(&this_rq->lock);
4157 wake_up_process(busiest->migration_thread);
4158 spin_lock(&this_rq->lock);
4161 sd->nr_balance_failed = 0;
4163 update_shares_locked(this_rq, sd);
4167 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
4168 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4169 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4171 sd->nr_balance_failed = 0;
4177 * idle_balance is called by schedule() if this_cpu is about to become
4178 * idle. Attempts to pull tasks from other CPUs.
4180 static void idle_balance(int this_cpu, struct rq *this_rq)
4182 struct sched_domain *sd;
4183 int pulled_task = 0;
4184 unsigned long next_balance = jiffies + HZ;
4186 for_each_domain(this_cpu, sd) {
4187 unsigned long interval;
4189 if (!(sd->flags & SD_LOAD_BALANCE))
4192 if (sd->flags & SD_BALANCE_NEWIDLE)
4193 /* If we've pulled tasks over stop searching: */
4194 pulled_task = load_balance_newidle(this_cpu, this_rq,
4197 interval = msecs_to_jiffies(sd->balance_interval);
4198 if (time_after(next_balance, sd->last_balance + interval))
4199 next_balance = sd->last_balance + interval;
4203 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
4205 * We are going idle. next_balance may be set based on
4206 * a busy processor. So reset next_balance.
4208 this_rq->next_balance = next_balance;
4213 * active_load_balance is run by migration threads. It pushes running tasks
4214 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4215 * running on each physical CPU where possible, and avoids physical /
4216 * logical imbalances.
4218 * Called with busiest_rq locked.
4220 static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
4222 int target_cpu = busiest_rq->push_cpu;
4223 struct sched_domain *sd;
4224 struct rq *target_rq;
4226 /* Is there any task to move? */
4227 if (busiest_rq->nr_running <= 1)
4230 target_rq = cpu_rq(target_cpu);
4233 * This condition is "impossible", if it occurs
4234 * we need to fix it. Originally reported by
4235 * Bjorn Helgaas on a 128-cpu setup.
4237 BUG_ON(busiest_rq == target_rq);
4239 /* move a task from busiest_rq to target_rq */
4240 double_lock_balance(busiest_rq, target_rq);
4241 update_rq_clock(busiest_rq);
4242 update_rq_clock(target_rq);
4244 /* Search for an sd spanning us and the target CPU. */
4245 for_each_domain(target_cpu, sd) {
4246 if ((sd->flags & SD_LOAD_BALANCE) &&
4247 cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
4252 schedstat_inc(sd, alb_count);
4254 if (move_one_task(target_rq, target_cpu, busiest_rq,
4256 schedstat_inc(sd, alb_pushed);
4258 schedstat_inc(sd, alb_failed);
4260 double_unlock_balance(busiest_rq, target_rq);
4265 atomic_t load_balancer;
4266 cpumask_var_t cpu_mask;
4267 } nohz ____cacheline_aligned = {
4268 .load_balancer = ATOMIC_INIT(-1),
4272 * This routine will try to nominate the ilb (idle load balancing)
4273 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4274 * load balancing on behalf of all those cpus. If all the cpus in the system
4275 * go into this tickless mode, then there will be no ilb owner (as there is
4276 * no need for one) and all the cpus will sleep till the next wakeup event
4279 * For the ilb owner, tick is not stopped. And this tick will be used
4280 * for idle load balancing. ilb owner will still be part of
4283 * While stopping the tick, this cpu will become the ilb owner if there
4284 * is no other owner. And will be the owner till that cpu becomes busy
4285 * or if all cpus in the system stop their ticks at which point
4286 * there is no need for ilb owner.
4288 * When the ilb owner becomes busy, it nominates another owner, during the
4289 * next busy scheduler_tick()
4291 int select_nohz_load_balancer(int stop_tick)
4293 int cpu = smp_processor_id();
4296 cpu_rq(cpu)->in_nohz_recently = 1;
4298 if (!cpu_active(cpu)) {
4299 if (atomic_read(&nohz.load_balancer) != cpu)
4303 * If we are going offline and still the leader,
4306 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
4312 cpumask_set_cpu(cpu, nohz.cpu_mask);
4314 /* time for ilb owner also to sleep */
4315 if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
4316 if (atomic_read(&nohz.load_balancer) == cpu)
4317 atomic_set(&nohz.load_balancer, -1);
4321 if (atomic_read(&nohz.load_balancer) == -1) {
4322 /* make me the ilb owner */
4323 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
4325 } else if (atomic_read(&nohz.load_balancer) == cpu)
4328 if (!cpumask_test_cpu(cpu, nohz.cpu_mask))
4331 cpumask_clear_cpu(cpu, nohz.cpu_mask);
4333 if (atomic_read(&nohz.load_balancer) == cpu)
4334 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
4341 static DEFINE_SPINLOCK(balancing);
4344 * It checks each scheduling domain to see if it is due to be balanced,
4345 * and initiates a balancing operation if so.
4347 * Balancing parameters are set up in arch_init_sched_domains.
4349 static void rebalance_domains(int cpu, enum cpu_idle_type idle)
4352 struct rq *rq = cpu_rq(cpu);
4353 unsigned long interval;
4354 struct sched_domain *sd;
4355 /* Earliest time when we have to do rebalance again */
4356 unsigned long next_balance = jiffies + 60*HZ;
4357 int update_next_balance = 0;
4360 for_each_domain(cpu, sd) {
4361 if (!(sd->flags & SD_LOAD_BALANCE))
4364 interval = sd->balance_interval;
4365 if (idle != CPU_IDLE)
4366 interval *= sd->busy_factor;
4368 /* scale ms to jiffies */
4369 interval = msecs_to_jiffies(interval);
4370 if (unlikely(!interval))
4372 if (interval > HZ*NR_CPUS/10)
4373 interval = HZ*NR_CPUS/10;
4375 need_serialize = sd->flags & SD_SERIALIZE;
4377 if (need_serialize) {
4378 if (!spin_trylock(&balancing))
4382 if (time_after_eq(jiffies, sd->last_balance + interval)) {
4383 if (load_balance(cpu, rq, sd, idle, &balance)) {
4385 * We've pulled tasks over so either we're no
4386 * longer idle, or one of our SMT siblings is
4389 idle = CPU_NOT_IDLE;
4391 sd->last_balance = jiffies;
4394 spin_unlock(&balancing);
4396 if (time_after(next_balance, sd->last_balance + interval)) {
4397 next_balance = sd->last_balance + interval;
4398 update_next_balance = 1;
4402 * Stop the load balance at this level. There is another
4403 * CPU in our sched group which is doing load balancing more
4411 * next_balance will be updated only when there is a need.
4412 * When the cpu is attached to null domain for ex, it will not be
4415 if (likely(update_next_balance))
4416 rq->next_balance = next_balance;
4420 * run_rebalance_domains is triggered when needed from the scheduler tick.
4421 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4422 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4424 static void run_rebalance_domains(struct softirq_action *h)
4426 int this_cpu = smp_processor_id();
4427 struct rq *this_rq = cpu_rq(this_cpu);
4428 enum cpu_idle_type idle = this_rq->idle_at_tick ?
4429 CPU_IDLE : CPU_NOT_IDLE;
4431 rebalance_domains(this_cpu, idle);
4435 * If this cpu is the owner for idle load balancing, then do the
4436 * balancing on behalf of the other idle cpus whose ticks are
4439 if (this_rq->idle_at_tick &&
4440 atomic_read(&nohz.load_balancer) == this_cpu) {
4444 for_each_cpu(balance_cpu, nohz.cpu_mask) {
4445 if (balance_cpu == this_cpu)
4449 * If this cpu gets work to do, stop the load balancing
4450 * work being done for other cpus. Next load
4451 * balancing owner will pick it up.
4456 rebalance_domains(balance_cpu, CPU_IDLE);
4458 rq = cpu_rq(balance_cpu);
4459 if (time_after(this_rq->next_balance, rq->next_balance))
4460 this_rq->next_balance = rq->next_balance;
4466 static inline int on_null_domain(int cpu)
4468 return !rcu_dereference(cpu_rq(cpu)->sd);
4472 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4474 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4475 * idle load balancing owner or decide to stop the periodic load balancing,
4476 * if the whole system is idle.
4478 static inline void trigger_load_balance(struct rq *rq, int cpu)
4482 * If we were in the nohz mode recently and busy at the current
4483 * scheduler tick, then check if we need to nominate new idle
4486 if (rq->in_nohz_recently && !rq->idle_at_tick) {
4487 rq->in_nohz_recently = 0;
4489 if (atomic_read(&nohz.load_balancer) == cpu) {
4490 cpumask_clear_cpu(cpu, nohz.cpu_mask);
4491 atomic_set(&nohz.load_balancer, -1);
4494 if (atomic_read(&nohz.load_balancer) == -1) {
4496 * simple selection for now: Nominate the
4497 * first cpu in the nohz list to be the next
4500 * TBD: Traverse the sched domains and nominate
4501 * the nearest cpu in the nohz.cpu_mask.
4503 int ilb = cpumask_first(nohz.cpu_mask);
4505 if (ilb < nr_cpu_ids)
4511 * If this cpu is idle and doing idle load balancing for all the
4512 * cpus with ticks stopped, is it time for that to stop?
4514 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
4515 cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
4521 * If this cpu is idle and the idle load balancing is done by
4522 * someone else, then no need raise the SCHED_SOFTIRQ
4524 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
4525 cpumask_test_cpu(cpu, nohz.cpu_mask))
4528 /* Don't need to rebalance while attached to NULL domain */
4529 if (time_after_eq(jiffies, rq->next_balance) &&
4530 likely(!on_null_domain(cpu)))
4531 raise_softirq(SCHED_SOFTIRQ);
4534 #else /* CONFIG_SMP */
4537 * on UP we do not need to balance between CPUs:
4539 static inline void idle_balance(int cpu, struct rq *rq)
4545 DEFINE_PER_CPU(struct kernel_stat, kstat);
4547 EXPORT_PER_CPU_SYMBOL(kstat);
4550 * Return any ns on the sched_clock that have not yet been banked in
4551 * @p in case that task is currently running.
4553 unsigned long long task_delta_exec(struct task_struct *p)
4555 unsigned long flags;
4559 rq = task_rq_lock(p, &flags);
4561 if (task_current(rq, p)) {
4564 update_rq_clock(rq);
4565 delta_exec = rq->clock - p->se.exec_start;
4566 if ((s64)delta_exec > 0)
4570 task_rq_unlock(rq, &flags);
4576 * Account user cpu time to a process.
4577 * @p: the process that the cpu time gets accounted to
4578 * @cputime: the cpu time spent in user space since the last update
4579 * @cputime_scaled: cputime scaled by cpu frequency
4581 void account_user_time(struct task_struct *p, cputime_t cputime,
4582 cputime_t cputime_scaled)
4584 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4587 /* Add user time to process. */
4588 p->utime = cputime_add(p->utime, cputime);
4589 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4590 account_group_user_time(p, cputime);
4592 /* Add user time to cpustat. */
4593 tmp = cputime_to_cputime64(cputime);
4594 if (TASK_NICE(p) > 0)
4595 cpustat->nice = cputime64_add(cpustat->nice, tmp);
4597 cpustat->user = cputime64_add(cpustat->user, tmp);
4598 /* Account for user time used */
4599 acct_update_integrals(p);
4603 * Account guest cpu time to a process.
4604 * @p: the process that the cpu time gets accounted to
4605 * @cputime: the cpu time spent in virtual machine since the last update
4606 * @cputime_scaled: cputime scaled by cpu frequency
4608 static void account_guest_time(struct task_struct *p, cputime_t cputime,
4609 cputime_t cputime_scaled)
4612 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4614 tmp = cputime_to_cputime64(cputime);
4616 /* Add guest time to process. */
4617 p->utime = cputime_add(p->utime, cputime);
4618 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4619 account_group_user_time(p, cputime);
4620 p->gtime = cputime_add(p->gtime, cputime);
4622 /* Add guest time to cpustat. */
4623 cpustat->user = cputime64_add(cpustat->user, tmp);
4624 cpustat->guest = cputime64_add(cpustat->guest, tmp);
4628 * Account system cpu time to a process.
4629 * @p: the process that the cpu time gets accounted to
4630 * @hardirq_offset: the offset to subtract from hardirq_count()
4631 * @cputime: the cpu time spent in kernel space since the last update
4632 * @cputime_scaled: cputime scaled by cpu frequency
4634 void account_system_time(struct task_struct *p, int hardirq_offset,
4635 cputime_t cputime, cputime_t cputime_scaled)
4637 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4640 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
4641 account_guest_time(p, cputime, cputime_scaled);
4645 /* Add system time to process. */
4646 p->stime = cputime_add(p->stime, cputime);
4647 p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
4648 account_group_system_time(p, cputime);
4650 /* Add system time to cpustat. */
4651 tmp = cputime_to_cputime64(cputime);
4652 if (hardirq_count() - hardirq_offset)
4653 cpustat->irq = cputime64_add(cpustat->irq, tmp);
4654 else if (softirq_count())
4655 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
4657 cpustat->system = cputime64_add(cpustat->system, tmp);
4659 /* Account for system time used */
4660 acct_update_integrals(p);
4664 * Account for involuntary wait time.
4665 * @steal: the cpu time spent in involuntary wait
4667 void account_steal_time(cputime_t cputime)
4669 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4670 cputime64_t cputime64 = cputime_to_cputime64(cputime);
4672 cpustat->steal = cputime64_add(cpustat->steal, cputime64);
4676 * Account for idle time.
4677 * @cputime: the cpu time spent in idle wait
4679 void account_idle_time(cputime_t cputime)
4681 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4682 cputime64_t cputime64 = cputime_to_cputime64(cputime);
4683 struct rq *rq = this_rq();
4685 if (atomic_read(&rq->nr_iowait) > 0)
4686 cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
4688 cpustat->idle = cputime64_add(cpustat->idle, cputime64);
4691 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4694 * Account a single tick of cpu time.
4695 * @p: the process that the cpu time gets accounted to
4696 * @user_tick: indicates if the tick is a user or a system tick
4698 void account_process_tick(struct task_struct *p, int user_tick)
4700 cputime_t one_jiffy = jiffies_to_cputime(1);
4701 cputime_t one_jiffy_scaled = cputime_to_scaled(one_jiffy);
4702 struct rq *rq = this_rq();
4705 account_user_time(p, one_jiffy, one_jiffy_scaled);
4706 else if (p != rq->idle)
4707 account_system_time(p, HARDIRQ_OFFSET, one_jiffy,
4710 account_idle_time(one_jiffy);
4714 * Account multiple ticks of steal time.
4715 * @p: the process from which the cpu time has been stolen
4716 * @ticks: number of stolen ticks
4718 void account_steal_ticks(unsigned long ticks)
4720 account_steal_time(jiffies_to_cputime(ticks));
4724 * Account multiple ticks of idle time.
4725 * @ticks: number of stolen ticks
4727 void account_idle_ticks(unsigned long ticks)
4729 account_idle_time(jiffies_to_cputime(ticks));
4735 * Use precise platform statistics if available:
4737 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4738 cputime_t task_utime(struct task_struct *p)
4743 cputime_t task_stime(struct task_struct *p)
4748 cputime_t task_utime(struct task_struct *p)
4750 clock_t utime = cputime_to_clock_t(p->utime),
4751 total = utime + cputime_to_clock_t(p->stime);
4755 * Use CFS's precise accounting:
4757 temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
4761 do_div(temp, total);
4763 utime = (clock_t)temp;
4765 p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
4766 return p->prev_utime;
4769 cputime_t task_stime(struct task_struct *p)
4774 * Use CFS's precise accounting. (we subtract utime from
4775 * the total, to make sure the total observed by userspace
4776 * grows monotonically - apps rely on that):
4778 stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
4779 cputime_to_clock_t(task_utime(p));
4782 p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime));
4784 return p->prev_stime;
4788 inline cputime_t task_gtime(struct task_struct *p)
4794 * This function gets called by the timer code, with HZ frequency.
4795 * We call it with interrupts disabled.
4797 * It also gets called by the fork code, when changing the parent's
4800 void scheduler_tick(void)
4802 int cpu = smp_processor_id();
4803 struct rq *rq = cpu_rq(cpu);
4804 struct task_struct *curr = rq->curr;
4808 spin_lock(&rq->lock);
4809 update_rq_clock(rq);
4810 update_cpu_load(rq);
4811 curr->sched_class->task_tick(rq, curr, 0);
4812 perf_counter_task_tick(curr, cpu);
4813 spin_unlock(&rq->lock);
4816 rq->idle_at_tick = idle_cpu(cpu);
4817 trigger_load_balance(rq, cpu);
4821 unsigned long get_parent_ip(unsigned long addr)
4823 if (in_lock_functions(addr)) {
4824 addr = CALLER_ADDR2;
4825 if (in_lock_functions(addr))
4826 addr = CALLER_ADDR3;
4831 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4832 defined(CONFIG_PREEMPT_TRACER))
4834 void __kprobes add_preempt_count(int val)
4836 #ifdef CONFIG_DEBUG_PREEMPT
4840 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4843 preempt_count() += val;
4844 #ifdef CONFIG_DEBUG_PREEMPT
4846 * Spinlock count overflowing soon?
4848 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
4851 if (preempt_count() == val)
4852 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4854 EXPORT_SYMBOL(add_preempt_count);
4856 void __kprobes sub_preempt_count(int val)
4858 #ifdef CONFIG_DEBUG_PREEMPT
4862 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
4865 * Is the spinlock portion underflowing?
4867 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
4868 !(preempt_count() & PREEMPT_MASK)))
4872 if (preempt_count() == val)
4873 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4874 preempt_count() -= val;
4876 EXPORT_SYMBOL(sub_preempt_count);
4881 * Print scheduling while atomic bug:
4883 static noinline void __schedule_bug(struct task_struct *prev)
4885 struct pt_regs *regs = get_irq_regs();
4887 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
4888 prev->comm, prev->pid, preempt_count());
4890 debug_show_held_locks(prev);
4892 if (irqs_disabled())
4893 print_irqtrace_events(prev);
4902 * Various schedule()-time debugging checks and statistics:
4904 static inline void schedule_debug(struct task_struct *prev)
4907 * Test if we are atomic. Since do_exit() needs to call into
4908 * schedule() atomically, we ignore that path for now.
4909 * Otherwise, whine if we are scheduling when we should not be.
4911 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
4912 __schedule_bug(prev);
4914 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
4916 schedstat_inc(this_rq(), sched_count);
4917 #ifdef CONFIG_SCHEDSTATS
4918 if (unlikely(prev->lock_depth >= 0)) {
4919 schedstat_inc(this_rq(), bkl_count);
4920 schedstat_inc(prev, sched_info.bkl_count);
4925 static void put_prev_task(struct rq *rq, struct task_struct *prev)
4927 if (prev->state == TASK_RUNNING) {
4928 u64 runtime = prev->se.sum_exec_runtime;
4930 runtime -= prev->se.prev_sum_exec_runtime;
4931 runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
4934 * In order to avoid avg_overlap growing stale when we are
4935 * indeed overlapping and hence not getting put to sleep, grow
4936 * the avg_overlap on preemption.
4938 * We use the average preemption runtime because that
4939 * correlates to the amount of cache footprint a task can
4942 update_avg(&prev->se.avg_overlap, runtime);
4944 prev->sched_class->put_prev_task(rq, prev);
4948 * Pick up the highest-prio task:
4950 static inline struct task_struct *
4951 pick_next_task(struct rq *rq)
4953 const struct sched_class *class;
4954 struct task_struct *p;
4957 * Optimization: we know that if all tasks are in
4958 * the fair class we can call that function directly:
4960 if (likely(rq->nr_running == rq->cfs.nr_running)) {
4961 p = fair_sched_class.pick_next_task(rq);
4966 class = sched_class_highest;
4968 p = class->pick_next_task(rq);
4972 * Will never be NULL as the idle class always
4973 * returns a non-NULL p:
4975 class = class->next;
4980 * schedule() is the main scheduler function.
4982 asmlinkage void __sched __schedule(void)
4984 struct task_struct *prev, *next;
4985 unsigned long *switch_count;
4989 cpu = smp_processor_id();
4993 switch_count = &prev->nivcsw;
4995 release_kernel_lock(prev);
4996 need_resched_nonpreemptible:
4998 schedule_debug(prev);
5000 if (sched_feat(HRTICK))
5003 spin_lock_irq(&rq->lock);
5004 update_rq_clock(rq);
5005 clear_tsk_need_resched(prev);
5007 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
5008 if (unlikely(signal_pending_state(prev->state, prev)))
5009 prev->state = TASK_RUNNING;
5011 deactivate_task(rq, prev, 1);
5012 switch_count = &prev->nvcsw;
5016 if (prev->sched_class->pre_schedule)
5017 prev->sched_class->pre_schedule(rq, prev);
5020 if (unlikely(!rq->nr_running))
5021 idle_balance(cpu, rq);
5023 put_prev_task(rq, prev);
5024 next = pick_next_task(rq);
5026 if (likely(prev != next)) {
5027 sched_info_switch(prev, next);
5028 perf_counter_task_sched_out(prev, cpu);
5034 context_switch(rq, prev, next); /* unlocks the rq */
5036 * the context switch might have flipped the stack from under
5037 * us, hence refresh the local variables.
5039 cpu = smp_processor_id();
5042 spin_unlock_irq(&rq->lock);
5044 if (unlikely(reacquire_kernel_lock(current) < 0))
5045 goto need_resched_nonpreemptible;
5048 asmlinkage void __sched schedule(void)
5053 preempt_enable_no_resched();
5054 if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
5057 EXPORT_SYMBOL(schedule);
5061 * Look out! "owner" is an entirely speculative pointer
5062 * access and not reliable.
5064 int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
5069 if (!sched_feat(OWNER_SPIN))
5072 #ifdef CONFIG_DEBUG_PAGEALLOC
5074 * Need to access the cpu field knowing that
5075 * DEBUG_PAGEALLOC could have unmapped it if
5076 * the mutex owner just released it and exited.
5078 if (probe_kernel_address(&owner->cpu, cpu))
5085 * Even if the access succeeded (likely case),
5086 * the cpu field may no longer be valid.
5088 if (cpu >= nr_cpumask_bits)
5092 * We need to validate that we can do a
5093 * get_cpu() and that we have the percpu area.
5095 if (!cpu_online(cpu))
5102 * Owner changed, break to re-assess state.
5104 if (lock->owner != owner)
5108 * Is that owner really running on that cpu?
5110 if (task_thread_info(rq->curr) != owner || need_resched())
5120 #ifdef CONFIG_PREEMPT
5122 * this is the entry point to schedule() from in-kernel preemption
5123 * off of preempt_enable. Kernel preemptions off return from interrupt
5124 * occur there and call schedule directly.
5126 asmlinkage void __sched preempt_schedule(void)
5128 struct thread_info *ti = current_thread_info();
5131 * If there is a non-zero preempt_count or interrupts are disabled,
5132 * we do not want to preempt the current task. Just return..
5134 if (likely(ti->preempt_count || irqs_disabled()))
5138 add_preempt_count(PREEMPT_ACTIVE);
5140 sub_preempt_count(PREEMPT_ACTIVE);
5143 * Check again in case we missed a preemption opportunity
5144 * between schedule and now.
5147 } while (need_resched());
5149 EXPORT_SYMBOL(preempt_schedule);
5152 * this is the entry point to schedule() from kernel preemption
5153 * off of irq context.
5154 * Note, that this is called and return with irqs disabled. This will
5155 * protect us against recursive calling from irq.
5157 asmlinkage void __sched preempt_schedule_irq(void)
5159 struct thread_info *ti = current_thread_info();
5161 /* Catch callers which need to be fixed */
5162 BUG_ON(ti->preempt_count || !irqs_disabled());
5165 add_preempt_count(PREEMPT_ACTIVE);
5168 local_irq_disable();
5169 sub_preempt_count(PREEMPT_ACTIVE);
5172 * Check again in case we missed a preemption opportunity
5173 * between schedule and now.
5176 } while (need_resched());
5179 #endif /* CONFIG_PREEMPT */
5181 int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
5184 return try_to_wake_up(curr->private, mode, sync);
5186 EXPORT_SYMBOL(default_wake_function);
5189 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5190 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5191 * number) then we wake all the non-exclusive tasks and one exclusive task.
5193 * There are circumstances in which we can try to wake a task which has already
5194 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5195 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5197 void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
5198 int nr_exclusive, int sync, void *key)
5200 wait_queue_t *curr, *next;
5202 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
5203 unsigned flags = curr->flags;
5205 if (curr->func(curr, mode, sync, key) &&
5206 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
5212 * __wake_up - wake up threads blocked on a waitqueue.
5214 * @mode: which threads
5215 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5216 * @key: is directly passed to the wakeup function
5218 void __wake_up(wait_queue_head_t *q, unsigned int mode,
5219 int nr_exclusive, void *key)
5221 unsigned long flags;
5223 spin_lock_irqsave(&q->lock, flags);
5224 __wake_up_common(q, mode, nr_exclusive, 0, key);
5225 spin_unlock_irqrestore(&q->lock, flags);
5227 EXPORT_SYMBOL(__wake_up);
5230 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5232 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
5234 __wake_up_common(q, mode, 1, 0, NULL);
5237 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
5239 __wake_up_common(q, mode, 1, 0, key);
5243 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5245 * @mode: which threads
5246 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5247 * @key: opaque value to be passed to wakeup targets
5249 * The sync wakeup differs that the waker knows that it will schedule
5250 * away soon, so while the target thread will be woken up, it will not
5251 * be migrated to another CPU - ie. the two threads are 'synchronized'
5252 * with each other. This can prevent needless bouncing between CPUs.
5254 * On UP it can prevent extra preemption.
5256 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
5257 int nr_exclusive, void *key)
5259 unsigned long flags;
5265 if (unlikely(!nr_exclusive))
5268 spin_lock_irqsave(&q->lock, flags);
5269 __wake_up_common(q, mode, nr_exclusive, sync, key);
5270 spin_unlock_irqrestore(&q->lock, flags);
5272 EXPORT_SYMBOL_GPL(__wake_up_sync_key);
5275 * __wake_up_sync - see __wake_up_sync_key()
5277 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
5279 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
5281 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
5284 * complete: - signals a single thread waiting on this completion
5285 * @x: holds the state of this particular completion
5287 * This will wake up a single thread waiting on this completion. Threads will be
5288 * awakened in the same order in which they were queued.
5290 * See also complete_all(), wait_for_completion() and related routines.
5292 void complete(struct completion *x)
5294 unsigned long flags;
5296 spin_lock_irqsave(&x->wait.lock, flags);
5298 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
5299 spin_unlock_irqrestore(&x->wait.lock, flags);
5301 EXPORT_SYMBOL(complete);
5304 * complete_all: - signals all threads waiting on this completion
5305 * @x: holds the state of this particular completion
5307 * This will wake up all threads waiting on this particular completion event.
5309 void complete_all(struct completion *x)
5311 unsigned long flags;
5313 spin_lock_irqsave(&x->wait.lock, flags);
5314 x->done += UINT_MAX/2;
5315 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
5316 spin_unlock_irqrestore(&x->wait.lock, flags);
5318 EXPORT_SYMBOL(complete_all);
5320 static inline long __sched
5321 do_wait_for_common(struct completion *x, long timeout, int state)
5324 DECLARE_WAITQUEUE(wait, current);
5326 wait.flags |= WQ_FLAG_EXCLUSIVE;
5327 __add_wait_queue_tail(&x->wait, &wait);
5329 if (signal_pending_state(state, current)) {
5330 timeout = -ERESTARTSYS;
5333 __set_current_state(state);
5334 spin_unlock_irq(&x->wait.lock);
5335 timeout = schedule_timeout(timeout);
5336 spin_lock_irq(&x->wait.lock);
5337 } while (!x->done && timeout);
5338 __remove_wait_queue(&x->wait, &wait);
5343 return timeout ?: 1;
5347 wait_for_common(struct completion *x, long timeout, int state)
5351 spin_lock_irq(&x->wait.lock);
5352 timeout = do_wait_for_common(x, timeout, state);
5353 spin_unlock_irq(&x->wait.lock);
5358 * wait_for_completion: - waits for completion of a task
5359 * @x: holds the state of this particular completion
5361 * This waits to be signaled for completion of a specific task. It is NOT
5362 * interruptible and there is no timeout.
5364 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5365 * and interrupt capability. Also see complete().
5367 void __sched wait_for_completion(struct completion *x)
5369 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
5371 EXPORT_SYMBOL(wait_for_completion);
5374 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
5375 * @x: holds the state of this particular completion
5376 * @timeout: timeout value in jiffies
5378 * This waits for either a completion of a specific task to be signaled or for a
5379 * specified timeout to expire. The timeout is in jiffies. It is not
5382 unsigned long __sched
5383 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
5385 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
5387 EXPORT_SYMBOL(wait_for_completion_timeout);
5390 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5391 * @x: holds the state of this particular completion
5393 * This waits for completion of a specific task to be signaled. It is
5396 int __sched wait_for_completion_interruptible(struct completion *x)
5398 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
5399 if (t == -ERESTARTSYS)
5403 EXPORT_SYMBOL(wait_for_completion_interruptible);
5406 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5407 * @x: holds the state of this particular completion
5408 * @timeout: timeout value in jiffies
5410 * This waits for either a completion of a specific task to be signaled or for a
5411 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5413 unsigned long __sched
5414 wait_for_completion_interruptible_timeout(struct completion *x,
5415 unsigned long timeout)
5417 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
5419 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
5422 * wait_for_completion_killable: - waits for completion of a task (killable)
5423 * @x: holds the state of this particular completion
5425 * This waits to be signaled for completion of a specific task. It can be
5426 * interrupted by a kill signal.
5428 int __sched wait_for_completion_killable(struct completion *x)
5430 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
5431 if (t == -ERESTARTSYS)
5435 EXPORT_SYMBOL(wait_for_completion_killable);
5438 * try_wait_for_completion - try to decrement a completion without blocking
5439 * @x: completion structure
5441 * Returns: 0 if a decrement cannot be done without blocking
5442 * 1 if a decrement succeeded.
5444 * If a completion is being used as a counting completion,
5445 * attempt to decrement the counter without blocking. This
5446 * enables us to avoid waiting if the resource the completion
5447 * is protecting is not available.
5449 bool try_wait_for_completion(struct completion *x)
5453 spin_lock_irq(&x->wait.lock);
5458 spin_unlock_irq(&x->wait.lock);
5461 EXPORT_SYMBOL(try_wait_for_completion);
5464 * completion_done - Test to see if a completion has any waiters
5465 * @x: completion structure
5467 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5468 * 1 if there are no waiters.
5471 bool completion_done(struct completion *x)
5475 spin_lock_irq(&x->wait.lock);
5478 spin_unlock_irq(&x->wait.lock);
5481 EXPORT_SYMBOL(completion_done);
5484 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
5486 unsigned long flags;
5489 init_waitqueue_entry(&wait, current);
5491 __set_current_state(state);
5493 spin_lock_irqsave(&q->lock, flags);
5494 __add_wait_queue(q, &wait);
5495 spin_unlock(&q->lock);
5496 timeout = schedule_timeout(timeout);
5497 spin_lock_irq(&q->lock);
5498 __remove_wait_queue(q, &wait);
5499 spin_unlock_irqrestore(&q->lock, flags);
5504 void __sched interruptible_sleep_on(wait_queue_head_t *q)
5506 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
5508 EXPORT_SYMBOL(interruptible_sleep_on);
5511 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
5513 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
5515 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
5517 void __sched sleep_on(wait_queue_head_t *q)
5519 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
5521 EXPORT_SYMBOL(sleep_on);
5523 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
5525 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
5527 EXPORT_SYMBOL(sleep_on_timeout);
5529 #ifdef CONFIG_RT_MUTEXES
5532 * rt_mutex_setprio - set the current priority of a task
5534 * @prio: prio value (kernel-internal form)
5536 * This function changes the 'effective' priority of a task. It does
5537 * not touch ->normal_prio like __setscheduler().
5539 * Used by the rt_mutex code to implement priority inheritance logic.
5541 void rt_mutex_setprio(struct task_struct *p, int prio)
5543 unsigned long flags;
5544 int oldprio, on_rq, running;
5546 const struct sched_class *prev_class = p->sched_class;
5548 BUG_ON(prio < 0 || prio > MAX_PRIO);
5550 rq = task_rq_lock(p, &flags);
5551 update_rq_clock(rq);
5554 on_rq = p->se.on_rq;
5555 running = task_current(rq, p);
5557 dequeue_task(rq, p, 0);
5559 p->sched_class->put_prev_task(rq, p);
5562 p->sched_class = &rt_sched_class;
5564 p->sched_class = &fair_sched_class;
5569 p->sched_class->set_curr_task(rq);
5571 enqueue_task(rq, p, 0);
5573 check_class_changed(rq, p, prev_class, oldprio, running);
5575 task_rq_unlock(rq, &flags);
5580 void set_user_nice(struct task_struct *p, long nice)
5582 int old_prio, delta, on_rq;
5583 unsigned long flags;
5586 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
5589 * We have to be careful, if called from sys_setpriority(),
5590 * the task might be in the middle of scheduling on another CPU.
5592 rq = task_rq_lock(p, &flags);
5593 update_rq_clock(rq);
5595 * The RT priorities are set via sched_setscheduler(), but we still
5596 * allow the 'normal' nice value to be set - but as expected
5597 * it wont have any effect on scheduling until the task is
5598 * SCHED_FIFO/SCHED_RR:
5600 if (task_has_rt_policy(p)) {
5601 p->static_prio = NICE_TO_PRIO(nice);
5604 on_rq = p->se.on_rq;
5606 dequeue_task(rq, p, 0);
5608 p->static_prio = NICE_TO_PRIO(nice);
5611 p->prio = effective_prio(p);
5612 delta = p->prio - old_prio;
5615 enqueue_task(rq, p, 0);
5617 * If the task increased its priority or is running and
5618 * lowered its priority, then reschedule its CPU:
5620 if (delta < 0 || (delta > 0 && task_running(rq, p)))
5621 resched_task(rq->curr);
5624 task_rq_unlock(rq, &flags);
5626 EXPORT_SYMBOL(set_user_nice);
5629 * can_nice - check if a task can reduce its nice value
5633 int can_nice(const struct task_struct *p, const int nice)
5635 /* convert nice value [19,-20] to rlimit style value [1,40] */
5636 int nice_rlim = 20 - nice;
5638 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
5639 capable(CAP_SYS_NICE));
5642 #ifdef __ARCH_WANT_SYS_NICE
5645 * sys_nice - change the priority of the current process.
5646 * @increment: priority increment
5648 * sys_setpriority is a more generic, but much slower function that
5649 * does similar things.
5651 SYSCALL_DEFINE1(nice, int, increment)
5656 * Setpriority might change our priority at the same moment.
5657 * We don't have to worry. Conceptually one call occurs first
5658 * and we have a single winner.
5660 if (increment < -40)
5665 nice = TASK_NICE(current) + increment;
5671 if (increment < 0 && !can_nice(current, nice))
5674 retval = security_task_setnice(current, nice);
5678 set_user_nice(current, nice);
5685 * task_prio - return the priority value of a given task.
5686 * @p: the task in question.
5688 * This is the priority value as seen by users in /proc.
5689 * RT tasks are offset by -200. Normal tasks are centered
5690 * around 0, value goes from -16 to +15.
5692 int task_prio(const struct task_struct *p)
5694 return p->prio - MAX_RT_PRIO;
5698 * task_nice - return the nice value of a given task.
5699 * @p: the task in question.
5701 int task_nice(const struct task_struct *p)
5703 return TASK_NICE(p);
5705 EXPORT_SYMBOL(task_nice);
5708 * idle_cpu - is a given cpu idle currently?
5709 * @cpu: the processor in question.
5711 int idle_cpu(int cpu)
5713 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
5717 * idle_task - return the idle task for a given cpu.
5718 * @cpu: the processor in question.
5720 struct task_struct *idle_task(int cpu)
5722 return cpu_rq(cpu)->idle;
5726 * find_process_by_pid - find a process with a matching PID value.
5727 * @pid: the pid in question.
5729 static struct task_struct *find_process_by_pid(pid_t pid)
5731 return pid ? find_task_by_vpid(pid) : current;
5734 /* Actually do priority change: must hold rq lock. */
5736 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
5738 BUG_ON(p->se.on_rq);
5741 switch (p->policy) {
5745 p->sched_class = &fair_sched_class;
5749 p->sched_class = &rt_sched_class;
5753 p->rt_priority = prio;
5754 p->normal_prio = normal_prio(p);
5755 /* we are holding p->pi_lock already */
5756 p->prio = rt_mutex_getprio(p);
5761 * check the target process has a UID that matches the current process's
5763 static bool check_same_owner(struct task_struct *p)
5765 const struct cred *cred = current_cred(), *pcred;
5769 pcred = __task_cred(p);
5770 match = (cred->euid == pcred->euid ||
5771 cred->euid == pcred->uid);
5776 static int __sched_setscheduler(struct task_struct *p, int policy,
5777 struct sched_param *param, bool user)
5779 int retval, oldprio, oldpolicy = -1, on_rq, running;
5780 unsigned long flags;
5781 const struct sched_class *prev_class = p->sched_class;
5784 /* may grab non-irq protected spin_locks */
5785 BUG_ON(in_interrupt());
5787 /* double check policy once rq lock held */
5789 policy = oldpolicy = p->policy;
5790 else if (policy != SCHED_FIFO && policy != SCHED_RR &&
5791 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
5792 policy != SCHED_IDLE)
5795 * Valid priorities for SCHED_FIFO and SCHED_RR are
5796 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5797 * SCHED_BATCH and SCHED_IDLE is 0.
5799 if (param->sched_priority < 0 ||
5800 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
5801 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
5803 if (rt_policy(policy) != (param->sched_priority != 0))
5807 * Allow unprivileged RT tasks to decrease priority:
5809 if (user && !capable(CAP_SYS_NICE)) {
5810 if (rt_policy(policy)) {
5811 unsigned long rlim_rtprio;
5813 if (!lock_task_sighand(p, &flags))
5815 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
5816 unlock_task_sighand(p, &flags);
5818 /* can't set/change the rt policy */
5819 if (policy != p->policy && !rlim_rtprio)
5822 /* can't increase priority */
5823 if (param->sched_priority > p->rt_priority &&
5824 param->sched_priority > rlim_rtprio)
5828 * Like positive nice levels, dont allow tasks to
5829 * move out of SCHED_IDLE either:
5831 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
5834 /* can't change other user's priorities */
5835 if (!check_same_owner(p))
5840 #ifdef CONFIG_RT_GROUP_SCHED
5842 * Do not allow realtime tasks into groups that have no runtime
5845 if (rt_bandwidth_enabled() && rt_policy(policy) &&
5846 task_group(p)->rt_bandwidth.rt_runtime == 0)
5850 retval = security_task_setscheduler(p, policy, param);
5856 * make sure no PI-waiters arrive (or leave) while we are
5857 * changing the priority of the task:
5859 spin_lock_irqsave(&p->pi_lock, flags);
5861 * To be able to change p->policy safely, the apropriate
5862 * runqueue lock must be held.
5864 rq = __task_rq_lock(p);
5865 /* recheck policy now with rq lock held */
5866 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
5867 policy = oldpolicy = -1;
5868 __task_rq_unlock(rq);
5869 spin_unlock_irqrestore(&p->pi_lock, flags);
5872 update_rq_clock(rq);
5873 on_rq = p->se.on_rq;
5874 running = task_current(rq, p);
5876 deactivate_task(rq, p, 0);
5878 p->sched_class->put_prev_task(rq, p);
5881 __setscheduler(rq, p, policy, param->sched_priority);
5884 p->sched_class->set_curr_task(rq);
5886 activate_task(rq, p, 0);
5888 check_class_changed(rq, p, prev_class, oldprio, running);
5890 __task_rq_unlock(rq);
5891 spin_unlock_irqrestore(&p->pi_lock, flags);
5893 rt_mutex_adjust_pi(p);
5899 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5900 * @p: the task in question.
5901 * @policy: new policy.
5902 * @param: structure containing the new RT priority.
5904 * NOTE that the task may be already dead.
5906 int sched_setscheduler(struct task_struct *p, int policy,
5907 struct sched_param *param)
5909 return __sched_setscheduler(p, policy, param, true);
5911 EXPORT_SYMBOL_GPL(sched_setscheduler);
5914 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5915 * @p: the task in question.
5916 * @policy: new policy.
5917 * @param: structure containing the new RT priority.
5919 * Just like sched_setscheduler, only don't bother checking if the
5920 * current context has permission. For example, this is needed in
5921 * stop_machine(): we create temporary high priority worker threads,
5922 * but our caller might not have that capability.
5924 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
5925 struct sched_param *param)
5927 return __sched_setscheduler(p, policy, param, false);
5931 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5933 struct sched_param lparam;
5934 struct task_struct *p;
5937 if (!param || pid < 0)
5939 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
5944 p = find_process_by_pid(pid);
5946 retval = sched_setscheduler(p, policy, &lparam);
5953 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5954 * @pid: the pid in question.
5955 * @policy: new policy.
5956 * @param: structure containing the new RT priority.
5958 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
5959 struct sched_param __user *, param)
5961 /* negative values for policy are not valid */
5965 return do_sched_setscheduler(pid, policy, param);
5969 * sys_sched_setparam - set/change the RT priority of a thread
5970 * @pid: the pid in question.
5971 * @param: structure containing the new RT priority.
5973 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
5975 return do_sched_setscheduler(pid, -1, param);
5979 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5980 * @pid: the pid in question.
5982 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
5984 struct task_struct *p;
5991 read_lock(&tasklist_lock);
5992 p = find_process_by_pid(pid);
5994 retval = security_task_getscheduler(p);
5998 read_unlock(&tasklist_lock);
6003 * sys_sched_getscheduler - get the RT priority of a thread
6004 * @pid: the pid in question.
6005 * @param: structure containing the RT priority.
6007 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
6009 struct sched_param lp;
6010 struct task_struct *p;
6013 if (!param || pid < 0)
6016 read_lock(&tasklist_lock);
6017 p = find_process_by_pid(pid);
6022 retval = security_task_getscheduler(p);
6026 lp.sched_priority = p->rt_priority;
6027 read_unlock(&tasklist_lock);
6030 * This one might sleep, we cannot do it with a spinlock held ...
6032 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
6037 read_unlock(&tasklist_lock);
6041 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
6043 cpumask_var_t cpus_allowed, new_mask;
6044 struct task_struct *p;
6048 read_lock(&tasklist_lock);
6050 p = find_process_by_pid(pid);
6052 read_unlock(&tasklist_lock);
6058 * It is not safe to call set_cpus_allowed with the
6059 * tasklist_lock held. We will bump the task_struct's
6060 * usage count and then drop tasklist_lock.
6063 read_unlock(&tasklist_lock);
6065 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
6069 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
6071 goto out_free_cpus_allowed;
6074 if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
6077 retval = security_task_setscheduler(p, 0, NULL);
6081 cpuset_cpus_allowed(p, cpus_allowed);
6082 cpumask_and(new_mask, in_mask, cpus_allowed);
6084 retval = set_cpus_allowed_ptr(p, new_mask);
6087 cpuset_cpus_allowed(p, cpus_allowed);
6088 if (!cpumask_subset(new_mask, cpus_allowed)) {
6090 * We must have raced with a concurrent cpuset
6091 * update. Just reset the cpus_allowed to the
6092 * cpuset's cpus_allowed
6094 cpumask_copy(new_mask, cpus_allowed);
6099 free_cpumask_var(new_mask);
6100 out_free_cpus_allowed:
6101 free_cpumask_var(cpus_allowed);
6108 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
6109 struct cpumask *new_mask)
6111 if (len < cpumask_size())
6112 cpumask_clear(new_mask);
6113 else if (len > cpumask_size())
6114 len = cpumask_size();
6116 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
6120 * sys_sched_setaffinity - set the cpu affinity of a process
6121 * @pid: pid of the process
6122 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6123 * @user_mask_ptr: user-space pointer to the new cpu mask
6125 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
6126 unsigned long __user *, user_mask_ptr)
6128 cpumask_var_t new_mask;
6131 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
6134 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
6136 retval = sched_setaffinity(pid, new_mask);
6137 free_cpumask_var(new_mask);
6141 long sched_getaffinity(pid_t pid, struct cpumask *mask)
6143 struct task_struct *p;
6147 read_lock(&tasklist_lock);
6150 p = find_process_by_pid(pid);
6154 retval = security_task_getscheduler(p);
6158 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
6161 read_unlock(&tasklist_lock);
6168 * sys_sched_getaffinity - get the cpu affinity of a process
6169 * @pid: pid of the process
6170 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6171 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6173 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
6174 unsigned long __user *, user_mask_ptr)
6179 if (len < cpumask_size())
6182 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
6185 ret = sched_getaffinity(pid, mask);
6187 if (copy_to_user(user_mask_ptr, mask, cpumask_size()))
6190 ret = cpumask_size();
6192 free_cpumask_var(mask);
6198 * sys_sched_yield - yield the current processor to other threads.
6200 * This function yields the current CPU to other tasks. If there are no
6201 * other threads running on this CPU then this function will return.
6203 SYSCALL_DEFINE0(sched_yield)
6205 struct rq *rq = this_rq_lock();
6207 schedstat_inc(rq, yld_count);
6208 current->sched_class->yield_task(rq);
6211 * Since we are going to call schedule() anyway, there's
6212 * no need to preempt or enable interrupts:
6214 __release(rq->lock);
6215 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
6216 _raw_spin_unlock(&rq->lock);
6217 preempt_enable_no_resched();
6224 static void __cond_resched(void)
6226 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
6227 __might_sleep(__FILE__, __LINE__);
6230 * The BKS might be reacquired before we have dropped
6231 * PREEMPT_ACTIVE, which could trigger a second
6232 * cond_resched() call.
6235 add_preempt_count(PREEMPT_ACTIVE);
6237 sub_preempt_count(PREEMPT_ACTIVE);
6238 } while (need_resched());
6241 int __sched _cond_resched(void)
6243 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
6244 system_state == SYSTEM_RUNNING) {
6250 EXPORT_SYMBOL(_cond_resched);
6253 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
6254 * call schedule, and on return reacquire the lock.
6256 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6257 * operations here to prevent schedule() from being called twice (once via
6258 * spin_unlock(), once by hand).
6260 int cond_resched_lock(spinlock_t *lock)
6262 int resched = need_resched() && system_state == SYSTEM_RUNNING;
6265 if (spin_needbreak(lock) || resched) {
6267 if (resched && need_resched())
6276 EXPORT_SYMBOL(cond_resched_lock);
6278 int __sched cond_resched_softirq(void)
6280 BUG_ON(!in_softirq());
6282 if (need_resched() && system_state == SYSTEM_RUNNING) {
6290 EXPORT_SYMBOL(cond_resched_softirq);
6293 * yield - yield the current processor to other threads.
6295 * This is a shortcut for kernel-space yielding - it marks the
6296 * thread runnable and calls sys_sched_yield().
6298 void __sched yield(void)
6300 set_current_state(TASK_RUNNING);
6303 EXPORT_SYMBOL(yield);
6306 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6307 * that process accounting knows that this is a task in IO wait state.
6309 * But don't do that if it is a deliberate, throttling IO wait (this task
6310 * has set its backing_dev_info: the queue against which it should throttle)
6312 void __sched io_schedule(void)
6314 struct rq *rq = &__raw_get_cpu_var(runqueues);
6316 delayacct_blkio_start();
6317 atomic_inc(&rq->nr_iowait);
6319 atomic_dec(&rq->nr_iowait);
6320 delayacct_blkio_end();
6322 EXPORT_SYMBOL(io_schedule);
6324 long __sched io_schedule_timeout(long timeout)
6326 struct rq *rq = &__raw_get_cpu_var(runqueues);
6329 delayacct_blkio_start();
6330 atomic_inc(&rq->nr_iowait);
6331 ret = schedule_timeout(timeout);
6332 atomic_dec(&rq->nr_iowait);
6333 delayacct_blkio_end();
6338 * sys_sched_get_priority_max - return maximum RT priority.
6339 * @policy: scheduling class.
6341 * this syscall returns the maximum rt_priority that can be used
6342 * by a given scheduling class.
6344 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
6351 ret = MAX_USER_RT_PRIO-1;
6363 * sys_sched_get_priority_min - return minimum RT priority.
6364 * @policy: scheduling class.
6366 * this syscall returns the minimum rt_priority that can be used
6367 * by a given scheduling class.
6369 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
6387 * sys_sched_rr_get_interval - return the default timeslice of a process.
6388 * @pid: pid of the process.
6389 * @interval: userspace pointer to the timeslice value.
6391 * this syscall writes the default timeslice value of a given process
6392 * into the user-space timespec buffer. A value of '0' means infinity.
6394 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
6395 struct timespec __user *, interval)
6397 struct task_struct *p;
6398 unsigned int time_slice;
6406 read_lock(&tasklist_lock);
6407 p = find_process_by_pid(pid);
6411 retval = security_task_getscheduler(p);
6416 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6417 * tasks that are on an otherwise idle runqueue:
6420 if (p->policy == SCHED_RR) {
6421 time_slice = DEF_TIMESLICE;
6422 } else if (p->policy != SCHED_FIFO) {
6423 struct sched_entity *se = &p->se;
6424 unsigned long flags;
6427 rq = task_rq_lock(p, &flags);
6428 if (rq->cfs.load.weight)
6429 time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
6430 task_rq_unlock(rq, &flags);
6432 read_unlock(&tasklist_lock);
6433 jiffies_to_timespec(time_slice, &t);
6434 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
6438 read_unlock(&tasklist_lock);
6442 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
6444 void sched_show_task(struct task_struct *p)
6446 unsigned long free = 0;
6449 state = p->state ? __ffs(p->state) + 1 : 0;
6450 printk(KERN_INFO "%-13.13s %c", p->comm,
6451 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
6452 #if BITS_PER_LONG == 32
6453 if (state == TASK_RUNNING)
6454 printk(KERN_CONT " running ");
6456 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
6458 if (state == TASK_RUNNING)
6459 printk(KERN_CONT " running task ");
6461 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
6463 #ifdef CONFIG_DEBUG_STACK_USAGE
6464 free = stack_not_used(p);
6466 printk(KERN_CONT "%5lu %5d %6d\n", free,
6467 task_pid_nr(p), task_pid_nr(p->real_parent));
6469 show_stack(p, NULL);
6472 void show_state_filter(unsigned long state_filter)
6474 struct task_struct *g, *p;
6476 #if BITS_PER_LONG == 32
6478 " task PC stack pid father\n");
6481 " task PC stack pid father\n");
6483 read_lock(&tasklist_lock);
6484 do_each_thread(g, p) {
6486 * reset the NMI-timeout, listing all files on a slow
6487 * console might take alot of time:
6489 touch_nmi_watchdog();
6490 if (!state_filter || (p->state & state_filter))
6492 } while_each_thread(g, p);
6494 touch_all_softlockup_watchdogs();
6496 #ifdef CONFIG_SCHED_DEBUG
6497 sysrq_sched_debug_show();
6499 read_unlock(&tasklist_lock);
6501 * Only show locks if all tasks are dumped:
6503 if (state_filter == -1)
6504 debug_show_all_locks();
6507 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
6509 idle->sched_class = &idle_sched_class;
6513 * init_idle - set up an idle thread for a given CPU
6514 * @idle: task in question
6515 * @cpu: cpu the idle task belongs to
6517 * NOTE: this function does not set the idle thread's NEED_RESCHED
6518 * flag, to make booting more robust.
6520 void __cpuinit init_idle(struct task_struct *idle, int cpu)
6522 struct rq *rq = cpu_rq(cpu);
6523 unsigned long flags;
6525 spin_lock_irqsave(&rq->lock, flags);
6528 idle->se.exec_start = sched_clock();
6530 idle->prio = idle->normal_prio = MAX_PRIO;
6531 cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
6532 __set_task_cpu(idle, cpu);
6534 rq->curr = rq->idle = idle;
6535 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6538 spin_unlock_irqrestore(&rq->lock, flags);
6540 /* Set the preempt count _outside_ the spinlocks! */
6541 #if defined(CONFIG_PREEMPT)
6542 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
6544 task_thread_info(idle)->preempt_count = 0;
6547 * The idle tasks have their own, simple scheduling class:
6549 idle->sched_class = &idle_sched_class;
6550 ftrace_graph_init_task(idle);
6554 * In a system that switches off the HZ timer nohz_cpu_mask
6555 * indicates which cpus entered this state. This is used
6556 * in the rcu update to wait only for active cpus. For system
6557 * which do not switch off the HZ timer nohz_cpu_mask should
6558 * always be CPU_BITS_NONE.
6560 cpumask_var_t nohz_cpu_mask;
6563 * Increase the granularity value when there are more CPUs,
6564 * because with more CPUs the 'effective latency' as visible
6565 * to users decreases. But the relationship is not linear,
6566 * so pick a second-best guess by going with the log2 of the
6569 * This idea comes from the SD scheduler of Con Kolivas:
6571 static inline void sched_init_granularity(void)
6573 unsigned int factor = 1 + ilog2(num_online_cpus());
6574 const unsigned long limit = 200000000;
6576 sysctl_sched_min_granularity *= factor;
6577 if (sysctl_sched_min_granularity > limit)
6578 sysctl_sched_min_granularity = limit;
6580 sysctl_sched_latency *= factor;
6581 if (sysctl_sched_latency > limit)
6582 sysctl_sched_latency = limit;
6584 sysctl_sched_wakeup_granularity *= factor;
6586 sysctl_sched_shares_ratelimit *= factor;
6591 * This is how migration works:
6593 * 1) we queue a struct migration_req structure in the source CPU's
6594 * runqueue and wake up that CPU's migration thread.
6595 * 2) we down() the locked semaphore => thread blocks.
6596 * 3) migration thread wakes up (implicitly it forces the migrated
6597 * thread off the CPU)
6598 * 4) it gets the migration request and checks whether the migrated
6599 * task is still in the wrong runqueue.
6600 * 5) if it's in the wrong runqueue then the migration thread removes
6601 * it and puts it into the right queue.
6602 * 6) migration thread up()s the semaphore.
6603 * 7) we wake up and the migration is done.
6607 * Change a given task's CPU affinity. Migrate the thread to a
6608 * proper CPU and schedule it away if the CPU it's executing on
6609 * is removed from the allowed bitmask.
6611 * NOTE: the caller must have a valid reference to the task, the
6612 * task must not exit() & deallocate itself prematurely. The
6613 * call is not atomic; no spinlocks may be held.
6615 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
6617 struct migration_req req;
6618 unsigned long flags;
6622 rq = task_rq_lock(p, &flags);
6623 if (!cpumask_intersects(new_mask, cpu_online_mask)) {
6628 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
6629 !cpumask_equal(&p->cpus_allowed, new_mask))) {
6634 if (p->sched_class->set_cpus_allowed)
6635 p->sched_class->set_cpus_allowed(p, new_mask);
6637 cpumask_copy(&p->cpus_allowed, new_mask);
6638 p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
6641 /* Can the task run on the task's current CPU? If so, we're done */
6642 if (cpumask_test_cpu(task_cpu(p), new_mask))
6645 if (migrate_task(p, cpumask_any_and(cpu_online_mask, new_mask), &req)) {
6646 /* Need help from migration thread: drop lock and wait. */
6647 task_rq_unlock(rq, &flags);
6648 wake_up_process(rq->migration_thread);
6649 wait_for_completion(&req.done);
6650 tlb_migrate_finish(p->mm);
6654 task_rq_unlock(rq, &flags);
6658 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
6661 * Move (not current) task off this cpu, onto dest cpu. We're doing
6662 * this because either it can't run here any more (set_cpus_allowed()
6663 * away from this CPU, or CPU going down), or because we're
6664 * attempting to rebalance this task on exec (sched_exec).
6666 * So we race with normal scheduler movements, but that's OK, as long
6667 * as the task is no longer on this CPU.
6669 * Returns non-zero if task was successfully migrated.
6671 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
6673 struct rq *rq_dest, *rq_src;
6676 if (unlikely(!cpu_active(dest_cpu)))
6679 rq_src = cpu_rq(src_cpu);
6680 rq_dest = cpu_rq(dest_cpu);
6682 double_rq_lock(rq_src, rq_dest);
6683 /* Already moved. */
6684 if (task_cpu(p) != src_cpu)
6686 /* Affinity changed (again). */
6687 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
6690 on_rq = p->se.on_rq;
6692 deactivate_task(rq_src, p, 0);
6694 set_task_cpu(p, dest_cpu);
6696 activate_task(rq_dest, p, 0);
6697 check_preempt_curr(rq_dest, p, 0);
6702 double_rq_unlock(rq_src, rq_dest);
6707 * migration_thread - this is a highprio system thread that performs
6708 * thread migration by bumping thread off CPU then 'pushing' onto
6711 static int migration_thread(void *data)
6713 int cpu = (long)data;
6717 BUG_ON(rq->migration_thread != current);
6719 set_current_state(TASK_INTERRUPTIBLE);
6720 while (!kthread_should_stop()) {
6721 struct migration_req *req;
6722 struct list_head *head;
6724 spin_lock_irq(&rq->lock);
6726 if (cpu_is_offline(cpu)) {
6727 spin_unlock_irq(&rq->lock);
6731 if (rq->active_balance) {
6732 active_load_balance(rq, cpu);
6733 rq->active_balance = 0;
6736 head = &rq->migration_queue;
6738 if (list_empty(head)) {
6739 spin_unlock_irq(&rq->lock);
6741 set_current_state(TASK_INTERRUPTIBLE);
6744 req = list_entry(head->next, struct migration_req, list);
6745 list_del_init(head->next);
6747 spin_unlock(&rq->lock);
6748 __migrate_task(req->task, cpu, req->dest_cpu);
6751 complete(&req->done);
6753 __set_current_state(TASK_RUNNING);
6757 /* Wait for kthread_stop */
6758 set_current_state(TASK_INTERRUPTIBLE);
6759 while (!kthread_should_stop()) {
6761 set_current_state(TASK_INTERRUPTIBLE);
6763 __set_current_state(TASK_RUNNING);
6767 #ifdef CONFIG_HOTPLUG_CPU
6769 static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
6773 local_irq_disable();
6774 ret = __migrate_task(p, src_cpu, dest_cpu);
6780 * Figure out where task on dead CPU should go, use force if necessary.
6782 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
6785 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(dead_cpu));
6788 /* Look for allowed, online CPU in same node. */
6789 for_each_cpu_and(dest_cpu, nodemask, cpu_online_mask)
6790 if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
6793 /* Any allowed, online CPU? */
6794 dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_online_mask);
6795 if (dest_cpu < nr_cpu_ids)
6798 /* No more Mr. Nice Guy. */
6799 if (dest_cpu >= nr_cpu_ids) {
6800 cpuset_cpus_allowed_locked(p, &p->cpus_allowed);
6801 dest_cpu = cpumask_any_and(cpu_online_mask, &p->cpus_allowed);
6804 * Don't tell them about moving exiting tasks or
6805 * kernel threads (both mm NULL), since they never
6808 if (p->mm && printk_ratelimit()) {
6809 printk(KERN_INFO "process %d (%s) no "
6810 "longer affine to cpu%d\n",
6811 task_pid_nr(p), p->comm, dead_cpu);
6816 /* It can have affinity changed while we were choosing. */
6817 if (unlikely(!__migrate_task_irq(p, dead_cpu, dest_cpu)))
6822 * While a dead CPU has no uninterruptible tasks queued at this point,
6823 * it might still have a nonzero ->nr_uninterruptible counter, because
6824 * for performance reasons the counter is not stricly tracking tasks to
6825 * their home CPUs. So we just add the counter to another CPU's counter,
6826 * to keep the global sum constant after CPU-down:
6828 static void migrate_nr_uninterruptible(struct rq *rq_src)
6830 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_online_mask));
6831 unsigned long flags;
6833 local_irq_save(flags);
6834 double_rq_lock(rq_src, rq_dest);
6835 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
6836 rq_src->nr_uninterruptible = 0;
6837 double_rq_unlock(rq_src, rq_dest);
6838 local_irq_restore(flags);
6841 /* Run through task list and migrate tasks from the dead cpu. */
6842 static void migrate_live_tasks(int src_cpu)
6844 struct task_struct *p, *t;
6846 read_lock(&tasklist_lock);
6848 do_each_thread(t, p) {
6852 if (task_cpu(p) == src_cpu)
6853 move_task_off_dead_cpu(src_cpu, p);
6854 } while_each_thread(t, p);
6856 read_unlock(&tasklist_lock);
6860 * Schedules idle task to be the next runnable task on current CPU.
6861 * It does so by boosting its priority to highest possible.
6862 * Used by CPU offline code.
6864 void sched_idle_next(void)
6866 int this_cpu = smp_processor_id();
6867 struct rq *rq = cpu_rq(this_cpu);
6868 struct task_struct *p = rq->idle;
6869 unsigned long flags;
6871 /* cpu has to be offline */
6872 BUG_ON(cpu_online(this_cpu));
6875 * Strictly not necessary since rest of the CPUs are stopped by now
6876 * and interrupts disabled on the current cpu.
6878 spin_lock_irqsave(&rq->lock, flags);
6880 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6882 update_rq_clock(rq);
6883 activate_task(rq, p, 0);
6885 spin_unlock_irqrestore(&rq->lock, flags);
6889 * Ensures that the idle task is using init_mm right before its cpu goes
6892 void idle_task_exit(void)
6894 struct mm_struct *mm = current->active_mm;
6896 BUG_ON(cpu_online(smp_processor_id()));
6899 switch_mm(mm, &init_mm, current);
6903 /* called under rq->lock with disabled interrupts */
6904 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
6906 struct rq *rq = cpu_rq(dead_cpu);
6908 /* Must be exiting, otherwise would be on tasklist. */
6909 BUG_ON(!p->exit_state);
6911 /* Cannot have done final schedule yet: would have vanished. */
6912 BUG_ON(p->state == TASK_DEAD);
6917 * Drop lock around migration; if someone else moves it,
6918 * that's OK. No task can be added to this CPU, so iteration is
6921 spin_unlock_irq(&rq->lock);
6922 move_task_off_dead_cpu(dead_cpu, p);
6923 spin_lock_irq(&rq->lock);
6928 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6929 static void migrate_dead_tasks(unsigned int dead_cpu)
6931 struct rq *rq = cpu_rq(dead_cpu);
6932 struct task_struct *next;
6935 if (!rq->nr_running)
6937 update_rq_clock(rq);
6938 next = pick_next_task(rq);
6941 next->sched_class->put_prev_task(rq, next);
6942 migrate_dead(dead_cpu, next);
6946 #endif /* CONFIG_HOTPLUG_CPU */
6948 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6950 static struct ctl_table sd_ctl_dir[] = {
6952 .procname = "sched_domain",
6958 static struct ctl_table sd_ctl_root[] = {
6960 .ctl_name = CTL_KERN,
6961 .procname = "kernel",
6963 .child = sd_ctl_dir,
6968 static struct ctl_table *sd_alloc_ctl_entry(int n)
6970 struct ctl_table *entry =
6971 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
6976 static void sd_free_ctl_entry(struct ctl_table **tablep)
6978 struct ctl_table *entry;
6981 * In the intermediate directories, both the child directory and
6982 * procname are dynamically allocated and could fail but the mode
6983 * will always be set. In the lowest directory the names are
6984 * static strings and all have proc handlers.
6986 for (entry = *tablep; entry->mode; entry++) {
6988 sd_free_ctl_entry(&entry->child);
6989 if (entry->proc_handler == NULL)
6990 kfree(entry->procname);
6998 set_table_entry(struct ctl_table *entry,
6999 const char *procname, void *data, int maxlen,
7000 mode_t mode, proc_handler *proc_handler)
7002 entry->procname = procname;
7004 entry->maxlen = maxlen;
7006 entry->proc_handler = proc_handler;
7009 static struct ctl_table *
7010 sd_alloc_ctl_domain_table(struct sched_domain *sd)
7012 struct ctl_table *table = sd_alloc_ctl_entry(13);
7017 set_table_entry(&table[0], "min_interval", &sd->min_interval,
7018 sizeof(long), 0644, proc_doulongvec_minmax);
7019 set_table_entry(&table[1], "max_interval", &sd->max_interval,
7020 sizeof(long), 0644, proc_doulongvec_minmax);
7021 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
7022 sizeof(int), 0644, proc_dointvec_minmax);
7023 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
7024 sizeof(int), 0644, proc_dointvec_minmax);
7025 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
7026 sizeof(int), 0644, proc_dointvec_minmax);
7027 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
7028 sizeof(int), 0644, proc_dointvec_minmax);
7029 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
7030 sizeof(int), 0644, proc_dointvec_minmax);
7031 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
7032 sizeof(int), 0644, proc_dointvec_minmax);
7033 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
7034 sizeof(int), 0644, proc_dointvec_minmax);
7035 set_table_entry(&table[9], "cache_nice_tries",
7036 &sd->cache_nice_tries,
7037 sizeof(int), 0644, proc_dointvec_minmax);
7038 set_table_entry(&table[10], "flags", &sd->flags,
7039 sizeof(int), 0644, proc_dointvec_minmax);
7040 set_table_entry(&table[11], "name", sd->name,
7041 CORENAME_MAX_SIZE, 0444, proc_dostring);
7042 /* &table[12] is terminator */
7047 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
7049 struct ctl_table *entry, *table;
7050 struct sched_domain *sd;
7051 int domain_num = 0, i;
7054 for_each_domain(cpu, sd)
7056 entry = table = sd_alloc_ctl_entry(domain_num + 1);
7061 for_each_domain(cpu, sd) {
7062 snprintf(buf, 32, "domain%d", i);
7063 entry->procname = kstrdup(buf, GFP_KERNEL);
7065 entry->child = sd_alloc_ctl_domain_table(sd);
7072 static struct ctl_table_header *sd_sysctl_header;
7073 static void register_sched_domain_sysctl(void)
7075 int i, cpu_num = num_online_cpus();
7076 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
7079 WARN_ON(sd_ctl_dir[0].child);
7080 sd_ctl_dir[0].child = entry;
7085 for_each_online_cpu(i) {
7086 snprintf(buf, 32, "cpu%d", i);
7087 entry->procname = kstrdup(buf, GFP_KERNEL);
7089 entry->child = sd_alloc_ctl_cpu_table(i);
7093 WARN_ON(sd_sysctl_header);
7094 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
7097 /* may be called multiple times per register */
7098 static void unregister_sched_domain_sysctl(void)
7100 if (sd_sysctl_header)
7101 unregister_sysctl_table(sd_sysctl_header);
7102 sd_sysctl_header = NULL;
7103 if (sd_ctl_dir[0].child)
7104 sd_free_ctl_entry(&sd_ctl_dir[0].child);
7107 static void register_sched_domain_sysctl(void)
7110 static void unregister_sched_domain_sysctl(void)
7115 static void set_rq_online(struct rq *rq)
7118 const struct sched_class *class;
7120 cpumask_set_cpu(rq->cpu, rq->rd->online);
7123 for_each_class(class) {
7124 if (class->rq_online)
7125 class->rq_online(rq);
7130 static void set_rq_offline(struct rq *rq)
7133 const struct sched_class *class;
7135 for_each_class(class) {
7136 if (class->rq_offline)
7137 class->rq_offline(rq);
7140 cpumask_clear_cpu(rq->cpu, rq->rd->online);
7146 * migration_call - callback that gets triggered when a CPU is added.
7147 * Here we can start up the necessary migration thread for the new CPU.
7149 static int __cpuinit
7150 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
7152 struct task_struct *p;
7153 int cpu = (long)hcpu;
7154 unsigned long flags;
7159 case CPU_UP_PREPARE:
7160 case CPU_UP_PREPARE_FROZEN:
7161 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
7164 kthread_bind(p, cpu);
7165 /* Must be high prio: stop_machine expects to yield to it. */
7166 rq = task_rq_lock(p, &flags);
7167 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
7168 task_rq_unlock(rq, &flags);
7169 cpu_rq(cpu)->migration_thread = p;
7173 case CPU_ONLINE_FROZEN:
7174 /* Strictly unnecessary, as first user will wake it. */
7175 wake_up_process(cpu_rq(cpu)->migration_thread);
7177 /* Update our root-domain */
7179 spin_lock_irqsave(&rq->lock, flags);
7181 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
7185 spin_unlock_irqrestore(&rq->lock, flags);
7188 #ifdef CONFIG_HOTPLUG_CPU
7189 case CPU_UP_CANCELED:
7190 case CPU_UP_CANCELED_FROZEN:
7191 if (!cpu_rq(cpu)->migration_thread)
7193 /* Unbind it from offline cpu so it can run. Fall thru. */
7194 kthread_bind(cpu_rq(cpu)->migration_thread,
7195 cpumask_any(cpu_online_mask));
7196 kthread_stop(cpu_rq(cpu)->migration_thread);
7197 cpu_rq(cpu)->migration_thread = NULL;
7201 case CPU_DEAD_FROZEN:
7202 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7203 migrate_live_tasks(cpu);
7205 kthread_stop(rq->migration_thread);
7206 rq->migration_thread = NULL;
7207 /* Idle task back to normal (off runqueue, low prio) */
7208 spin_lock_irq(&rq->lock);
7209 update_rq_clock(rq);
7210 deactivate_task(rq, rq->idle, 0);
7211 rq->idle->static_prio = MAX_PRIO;
7212 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
7213 rq->idle->sched_class = &idle_sched_class;
7214 migrate_dead_tasks(cpu);
7215 spin_unlock_irq(&rq->lock);
7217 migrate_nr_uninterruptible(rq);
7218 BUG_ON(rq->nr_running != 0);
7221 * No need to migrate the tasks: it was best-effort if
7222 * they didn't take sched_hotcpu_mutex. Just wake up
7225 spin_lock_irq(&rq->lock);
7226 while (!list_empty(&rq->migration_queue)) {
7227 struct migration_req *req;
7229 req = list_entry(rq->migration_queue.next,
7230 struct migration_req, list);
7231 list_del_init(&req->list);
7232 spin_unlock_irq(&rq->lock);
7233 complete(&req->done);
7234 spin_lock_irq(&rq->lock);
7236 spin_unlock_irq(&rq->lock);
7240 case CPU_DYING_FROZEN:
7241 /* Update our root-domain */
7243 spin_lock_irqsave(&rq->lock, flags);
7245 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
7248 spin_unlock_irqrestore(&rq->lock, flags);
7255 /* Register at highest priority so that task migration (migrate_all_tasks)
7256 * happens before everything else.
7258 static struct notifier_block __cpuinitdata migration_notifier = {
7259 .notifier_call = migration_call,
7263 static int __init migration_init(void)
7265 void *cpu = (void *)(long)smp_processor_id();
7268 /* Start one for the boot CPU: */
7269 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
7270 BUG_ON(err == NOTIFY_BAD);
7271 migration_call(&migration_notifier, CPU_ONLINE, cpu);
7272 register_cpu_notifier(&migration_notifier);
7276 early_initcall(migration_init);
7281 #ifdef CONFIG_SCHED_DEBUG
7283 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
7284 struct cpumask *groupmask)
7286 struct sched_group *group = sd->groups;
7289 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
7290 cpumask_clear(groupmask);
7292 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
7294 if (!(sd->flags & SD_LOAD_BALANCE)) {
7295 printk("does not load-balance\n");
7297 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
7302 printk(KERN_CONT "span %s level %s\n", str, sd->name);
7304 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
7305 printk(KERN_ERR "ERROR: domain->span does not contain "
7308 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
7309 printk(KERN_ERR "ERROR: domain->groups does not contain"
7313 printk(KERN_DEBUG "%*s groups:", level + 1, "");
7317 printk(KERN_ERR "ERROR: group is NULL\n");
7321 if (!group->__cpu_power) {
7322 printk(KERN_CONT "\n");
7323 printk(KERN_ERR "ERROR: domain->cpu_power not "
7328 if (!cpumask_weight(sched_group_cpus(group))) {
7329 printk(KERN_CONT "\n");
7330 printk(KERN_ERR "ERROR: empty group\n");
7334 if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
7335 printk(KERN_CONT "\n");
7336 printk(KERN_ERR "ERROR: repeated CPUs\n");
7340 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
7342 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
7343 printk(KERN_CONT " %s", str);
7345 group = group->next;
7346 } while (group != sd->groups);
7347 printk(KERN_CONT "\n");
7349 if (!cpumask_equal(sched_domain_span(sd), groupmask))
7350 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
7353 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
7354 printk(KERN_ERR "ERROR: parent span is not a superset "
7355 "of domain->span\n");
7359 static void sched_domain_debug(struct sched_domain *sd, int cpu)
7361 cpumask_var_t groupmask;
7365 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
7369 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
7371 if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) {
7372 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
7377 if (sched_domain_debug_one(sd, cpu, level, groupmask))
7384 free_cpumask_var(groupmask);
7386 #else /* !CONFIG_SCHED_DEBUG */
7387 # define sched_domain_debug(sd, cpu) do { } while (0)
7388 #endif /* CONFIG_SCHED_DEBUG */
7390 static int sd_degenerate(struct sched_domain *sd)
7392 if (cpumask_weight(sched_domain_span(sd)) == 1)
7395 /* Following flags need at least 2 groups */
7396 if (sd->flags & (SD_LOAD_BALANCE |
7397 SD_BALANCE_NEWIDLE |
7401 SD_SHARE_PKG_RESOURCES)) {
7402 if (sd->groups != sd->groups->next)
7406 /* Following flags don't use groups */
7407 if (sd->flags & (SD_WAKE_IDLE |
7416 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
7418 unsigned long cflags = sd->flags, pflags = parent->flags;
7420 if (sd_degenerate(parent))
7423 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
7426 /* Does parent contain flags not in child? */
7427 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7428 if (cflags & SD_WAKE_AFFINE)
7429 pflags &= ~SD_WAKE_BALANCE;
7430 /* Flags needing groups don't count if only 1 group in parent */
7431 if (parent->groups == parent->groups->next) {
7432 pflags &= ~(SD_LOAD_BALANCE |
7433 SD_BALANCE_NEWIDLE |
7437 SD_SHARE_PKG_RESOURCES);
7438 if (nr_node_ids == 1)
7439 pflags &= ~SD_SERIALIZE;
7441 if (~cflags & pflags)
7447 static void free_rootdomain(struct root_domain *rd)
7449 cpupri_cleanup(&rd->cpupri);
7451 free_cpumask_var(rd->rto_mask);
7452 free_cpumask_var(rd->online);
7453 free_cpumask_var(rd->span);
7457 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
7459 struct root_domain *old_rd = NULL;
7460 unsigned long flags;
7462 spin_lock_irqsave(&rq->lock, flags);
7467 if (cpumask_test_cpu(rq->cpu, old_rd->online))
7470 cpumask_clear_cpu(rq->cpu, old_rd->span);
7473 * If we dont want to free the old_rt yet then
7474 * set old_rd to NULL to skip the freeing later
7477 if (!atomic_dec_and_test(&old_rd->refcount))
7481 atomic_inc(&rd->refcount);
7484 cpumask_set_cpu(rq->cpu, rd->span);
7485 if (cpumask_test_cpu(rq->cpu, cpu_online_mask))
7488 spin_unlock_irqrestore(&rq->lock, flags);
7491 free_rootdomain(old_rd);
7494 static int __init_refok init_rootdomain(struct root_domain *rd, bool bootmem)
7496 memset(rd, 0, sizeof(*rd));
7499 alloc_bootmem_cpumask_var(&def_root_domain.span);
7500 alloc_bootmem_cpumask_var(&def_root_domain.online);
7501 alloc_bootmem_cpumask_var(&def_root_domain.rto_mask);
7502 cpupri_init(&rd->cpupri, true);
7506 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
7508 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
7510 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
7513 if (cpupri_init(&rd->cpupri, false) != 0)
7518 free_cpumask_var(rd->rto_mask);
7520 free_cpumask_var(rd->online);
7522 free_cpumask_var(rd->span);
7527 static void init_defrootdomain(void)
7529 init_rootdomain(&def_root_domain, true);
7531 atomic_set(&def_root_domain.refcount, 1);
7534 static struct root_domain *alloc_rootdomain(void)
7536 struct root_domain *rd;
7538 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
7542 if (init_rootdomain(rd, false) != 0) {
7551 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7552 * hold the hotplug lock.
7555 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
7557 struct rq *rq = cpu_rq(cpu);
7558 struct sched_domain *tmp;
7560 /* Remove the sched domains which do not contribute to scheduling. */
7561 for (tmp = sd; tmp; ) {
7562 struct sched_domain *parent = tmp->parent;
7566 if (sd_parent_degenerate(tmp, parent)) {
7567 tmp->parent = parent->parent;
7569 parent->parent->child = tmp;
7574 if (sd && sd_degenerate(sd)) {
7580 sched_domain_debug(sd, cpu);
7582 rq_attach_root(rq, rd);
7583 rcu_assign_pointer(rq->sd, sd);
7586 /* cpus with isolated domains */
7587 static cpumask_var_t cpu_isolated_map;
7589 /* Setup the mask of cpus configured for isolated domains */
7590 static int __init isolated_cpu_setup(char *str)
7592 cpulist_parse(str, cpu_isolated_map);
7596 __setup("isolcpus=", isolated_cpu_setup);
7599 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7600 * to a function which identifies what group(along with sched group) a CPU
7601 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7602 * (due to the fact that we keep track of groups covered with a struct cpumask).
7604 * init_sched_build_groups will build a circular linked list of the groups
7605 * covered by the given span, and will set each group's ->cpumask correctly,
7606 * and ->cpu_power to 0.
7609 init_sched_build_groups(const struct cpumask *span,
7610 const struct cpumask *cpu_map,
7611 int (*group_fn)(int cpu, const struct cpumask *cpu_map,
7612 struct sched_group **sg,
7613 struct cpumask *tmpmask),
7614 struct cpumask *covered, struct cpumask *tmpmask)
7616 struct sched_group *first = NULL, *last = NULL;
7619 cpumask_clear(covered);
7621 for_each_cpu(i, span) {
7622 struct sched_group *sg;
7623 int group = group_fn(i, cpu_map, &sg, tmpmask);
7626 if (cpumask_test_cpu(i, covered))
7629 cpumask_clear(sched_group_cpus(sg));
7630 sg->__cpu_power = 0;
7632 for_each_cpu(j, span) {
7633 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
7636 cpumask_set_cpu(j, covered);
7637 cpumask_set_cpu(j, sched_group_cpus(sg));
7648 #define SD_NODES_PER_DOMAIN 16
7653 * find_next_best_node - find the next node to include in a sched_domain
7654 * @node: node whose sched_domain we're building
7655 * @used_nodes: nodes already in the sched_domain
7657 * Find the next node to include in a given scheduling domain. Simply
7658 * finds the closest node not already in the @used_nodes map.
7660 * Should use nodemask_t.
7662 static int find_next_best_node(int node, nodemask_t *used_nodes)
7664 int i, n, val, min_val, best_node = 0;
7668 for (i = 0; i < nr_node_ids; i++) {
7669 /* Start at @node */
7670 n = (node + i) % nr_node_ids;
7672 if (!nr_cpus_node(n))
7675 /* Skip already used nodes */
7676 if (node_isset(n, *used_nodes))
7679 /* Simple min distance search */
7680 val = node_distance(node, n);
7682 if (val < min_val) {
7688 node_set(best_node, *used_nodes);
7693 * sched_domain_node_span - get a cpumask for a node's sched_domain
7694 * @node: node whose cpumask we're constructing
7695 * @span: resulting cpumask
7697 * Given a node, construct a good cpumask for its sched_domain to span. It
7698 * should be one that prevents unnecessary balancing, but also spreads tasks
7701 static void sched_domain_node_span(int node, struct cpumask *span)
7703 nodemask_t used_nodes;
7706 cpumask_clear(span);
7707 nodes_clear(used_nodes);
7709 cpumask_or(span, span, cpumask_of_node(node));
7710 node_set(node, used_nodes);
7712 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
7713 int next_node = find_next_best_node(node, &used_nodes);
7715 cpumask_or(span, span, cpumask_of_node(next_node));
7718 #endif /* CONFIG_NUMA */
7720 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
7723 * The cpus mask in sched_group and sched_domain hangs off the end.
7724 * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
7725 * for nr_cpu_ids < CONFIG_NR_CPUS.
7727 struct static_sched_group {
7728 struct sched_group sg;
7729 DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
7732 struct static_sched_domain {
7733 struct sched_domain sd;
7734 DECLARE_BITMAP(span, CONFIG_NR_CPUS);
7738 * SMT sched-domains:
7740 #ifdef CONFIG_SCHED_SMT
7741 static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
7742 static DEFINE_PER_CPU(struct static_sched_group, sched_group_cpus);
7745 cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map,
7746 struct sched_group **sg, struct cpumask *unused)
7749 *sg = &per_cpu(sched_group_cpus, cpu).sg;
7752 #endif /* CONFIG_SCHED_SMT */
7755 * multi-core sched-domains:
7757 #ifdef CONFIG_SCHED_MC
7758 static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
7759 static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
7760 #endif /* CONFIG_SCHED_MC */
7762 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7764 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
7765 struct sched_group **sg, struct cpumask *mask)
7769 cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
7770 group = cpumask_first(mask);
7772 *sg = &per_cpu(sched_group_core, group).sg;
7775 #elif defined(CONFIG_SCHED_MC)
7777 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
7778 struct sched_group **sg, struct cpumask *unused)
7781 *sg = &per_cpu(sched_group_core, cpu).sg;
7786 static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
7787 static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
7790 cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
7791 struct sched_group **sg, struct cpumask *mask)
7794 #ifdef CONFIG_SCHED_MC
7795 cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
7796 group = cpumask_first(mask);
7797 #elif defined(CONFIG_SCHED_SMT)
7798 cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
7799 group = cpumask_first(mask);
7804 *sg = &per_cpu(sched_group_phys, group).sg;
7810 * The init_sched_build_groups can't handle what we want to do with node
7811 * groups, so roll our own. Now each node has its own list of groups which
7812 * gets dynamically allocated.
7814 static DEFINE_PER_CPU(struct static_sched_domain, node_domains);
7815 static struct sched_group ***sched_group_nodes_bycpu;
7817 static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
7818 static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
7820 static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
7821 struct sched_group **sg,
7822 struct cpumask *nodemask)
7826 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map);
7827 group = cpumask_first(nodemask);
7830 *sg = &per_cpu(sched_group_allnodes, group).sg;
7834 static void init_numa_sched_groups_power(struct sched_group *group_head)
7836 struct sched_group *sg = group_head;
7842 for_each_cpu(j, sched_group_cpus(sg)) {
7843 struct sched_domain *sd;
7845 sd = &per_cpu(phys_domains, j).sd;
7846 if (j != cpumask_first(sched_group_cpus(sd->groups))) {
7848 * Only add "power" once for each
7854 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
7857 } while (sg != group_head);
7859 #endif /* CONFIG_NUMA */
7862 /* Free memory allocated for various sched_group structures */
7863 static void free_sched_groups(const struct cpumask *cpu_map,
7864 struct cpumask *nodemask)
7868 for_each_cpu(cpu, cpu_map) {
7869 struct sched_group **sched_group_nodes
7870 = sched_group_nodes_bycpu[cpu];
7872 if (!sched_group_nodes)
7875 for (i = 0; i < nr_node_ids; i++) {
7876 struct sched_group *oldsg, *sg = sched_group_nodes[i];
7878 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
7879 if (cpumask_empty(nodemask))
7889 if (oldsg != sched_group_nodes[i])
7892 kfree(sched_group_nodes);
7893 sched_group_nodes_bycpu[cpu] = NULL;
7896 #else /* !CONFIG_NUMA */
7897 static void free_sched_groups(const struct cpumask *cpu_map,
7898 struct cpumask *nodemask)
7901 #endif /* CONFIG_NUMA */
7904 * Initialize sched groups cpu_power.
7906 * cpu_power indicates the capacity of sched group, which is used while
7907 * distributing the load between different sched groups in a sched domain.
7908 * Typically cpu_power for all the groups in a sched domain will be same unless
7909 * there are asymmetries in the topology. If there are asymmetries, group
7910 * having more cpu_power will pickup more load compared to the group having
7913 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7914 * the maximum number of tasks a group can handle in the presence of other idle
7915 * or lightly loaded groups in the same sched domain.
7917 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
7919 struct sched_domain *child;
7920 struct sched_group *group;
7922 WARN_ON(!sd || !sd->groups);
7924 if (cpu != cpumask_first(sched_group_cpus(sd->groups)))
7929 sd->groups->__cpu_power = 0;
7932 * For perf policy, if the groups in child domain share resources
7933 * (for example cores sharing some portions of the cache hierarchy
7934 * or SMT), then set this domain groups cpu_power such that each group
7935 * can handle only one task, when there are other idle groups in the
7936 * same sched domain.
7938 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
7940 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
7941 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
7946 * add cpu_power of each child group to this groups cpu_power
7948 group = child->groups;
7950 sg_inc_cpu_power(sd->groups, group->__cpu_power);
7951 group = group->next;
7952 } while (group != child->groups);
7956 * Initializers for schedule domains
7957 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7960 #ifdef CONFIG_SCHED_DEBUG
7961 # define SD_INIT_NAME(sd, type) sd->name = #type
7963 # define SD_INIT_NAME(sd, type) do { } while (0)
7966 #define SD_INIT(sd, type) sd_init_##type(sd)
7968 #define SD_INIT_FUNC(type) \
7969 static noinline void sd_init_##type(struct sched_domain *sd) \
7971 memset(sd, 0, sizeof(*sd)); \
7972 *sd = SD_##type##_INIT; \
7973 sd->level = SD_LV_##type; \
7974 SD_INIT_NAME(sd, type); \
7979 SD_INIT_FUNC(ALLNODES)
7982 #ifdef CONFIG_SCHED_SMT
7983 SD_INIT_FUNC(SIBLING)
7985 #ifdef CONFIG_SCHED_MC
7989 static int default_relax_domain_level = -1;
7991 static int __init setup_relax_domain_level(char *str)
7995 val = simple_strtoul(str, NULL, 0);
7996 if (val < SD_LV_MAX)
7997 default_relax_domain_level = val;
8001 __setup("relax_domain_level=", setup_relax_domain_level);
8003 static void set_domain_attribute(struct sched_domain *sd,
8004 struct sched_domain_attr *attr)
8008 if (!attr || attr->relax_domain_level < 0) {
8009 if (default_relax_domain_level < 0)
8012 request = default_relax_domain_level;
8014 request = attr->relax_domain_level;
8015 if (request < sd->level) {
8016 /* turn off idle balance on this domain */
8017 sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
8019 /* turn on idle balance on this domain */
8020 sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
8025 * Build sched domains for a given set of cpus and attach the sched domains
8026 * to the individual cpus
8028 static int __build_sched_domains(const struct cpumask *cpu_map,
8029 struct sched_domain_attr *attr)
8031 int i, err = -ENOMEM;
8032 struct root_domain *rd;
8033 cpumask_var_t nodemask, this_sibling_map, this_core_map, send_covered,
8036 cpumask_var_t domainspan, covered, notcovered;
8037 struct sched_group **sched_group_nodes = NULL;
8038 int sd_allnodes = 0;
8040 if (!alloc_cpumask_var(&domainspan, GFP_KERNEL))
8042 if (!alloc_cpumask_var(&covered, GFP_KERNEL))
8043 goto free_domainspan;
8044 if (!alloc_cpumask_var(¬covered, GFP_KERNEL))
8048 if (!alloc_cpumask_var(&nodemask, GFP_KERNEL))
8049 goto free_notcovered;
8050 if (!alloc_cpumask_var(&this_sibling_map, GFP_KERNEL))
8052 if (!alloc_cpumask_var(&this_core_map, GFP_KERNEL))
8053 goto free_this_sibling_map;
8054 if (!alloc_cpumask_var(&send_covered, GFP_KERNEL))
8055 goto free_this_core_map;
8056 if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
8057 goto free_send_covered;
8061 * Allocate the per-node list of sched groups
8063 sched_group_nodes = kcalloc(nr_node_ids, sizeof(struct sched_group *),
8065 if (!sched_group_nodes) {
8066 printk(KERN_WARNING "Can not alloc sched group node list\n");
8071 rd = alloc_rootdomain();
8073 printk(KERN_WARNING "Cannot alloc root domain\n");
8074 goto free_sched_groups;
8078 sched_group_nodes_bycpu[cpumask_first(cpu_map)] = sched_group_nodes;
8082 * Set up domains for cpus specified by the cpu_map.
8084 for_each_cpu(i, cpu_map) {
8085 struct sched_domain *sd = NULL, *p;
8087 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(i)), cpu_map);
8090 if (cpumask_weight(cpu_map) >
8091 SD_NODES_PER_DOMAIN*cpumask_weight(nodemask)) {
8092 sd = &per_cpu(allnodes_domains, i).sd;
8093 SD_INIT(sd, ALLNODES);
8094 set_domain_attribute(sd, attr);
8095 cpumask_copy(sched_domain_span(sd), cpu_map);
8096 cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
8102 sd = &per_cpu(node_domains, i).sd;
8104 set_domain_attribute(sd, attr);
8105 sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd));
8109 cpumask_and(sched_domain_span(sd),
8110 sched_domain_span(sd), cpu_map);
8114 sd = &per_cpu(phys_domains, i).sd;
8116 set_domain_attribute(sd, attr);
8117 cpumask_copy(sched_domain_span(sd), nodemask);
8121 cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
8123 #ifdef CONFIG_SCHED_MC
8125 sd = &per_cpu(core_domains, i).sd;
8127 set_domain_attribute(sd, attr);
8128 cpumask_and(sched_domain_span(sd), cpu_map,
8129 cpu_coregroup_mask(i));
8132 cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
8135 #ifdef CONFIG_SCHED_SMT
8137 sd = &per_cpu(cpu_domains, i).sd;
8138 SD_INIT(sd, SIBLING);
8139 set_domain_attribute(sd, attr);
8140 cpumask_and(sched_domain_span(sd),
8141 topology_thread_cpumask(i), cpu_map);
8144 cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
8148 #ifdef CONFIG_SCHED_SMT
8149 /* Set up CPU (sibling) groups */
8150 for_each_cpu(i, cpu_map) {
8151 cpumask_and(this_sibling_map,
8152 topology_thread_cpumask(i), cpu_map);
8153 if (i != cpumask_first(this_sibling_map))
8156 init_sched_build_groups(this_sibling_map, cpu_map,
8158 send_covered, tmpmask);
8162 #ifdef CONFIG_SCHED_MC
8163 /* Set up multi-core groups */
8164 for_each_cpu(i, cpu_map) {
8165 cpumask_and(this_core_map, cpu_coregroup_mask(i), cpu_map);
8166 if (i != cpumask_first(this_core_map))
8169 init_sched_build_groups(this_core_map, cpu_map,
8171 send_covered, tmpmask);
8175 /* Set up physical groups */
8176 for (i = 0; i < nr_node_ids; i++) {
8177 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
8178 if (cpumask_empty(nodemask))
8181 init_sched_build_groups(nodemask, cpu_map,
8183 send_covered, tmpmask);
8187 /* Set up node groups */
8189 init_sched_build_groups(cpu_map, cpu_map,
8190 &cpu_to_allnodes_group,
8191 send_covered, tmpmask);
8194 for (i = 0; i < nr_node_ids; i++) {
8195 /* Set up node groups */
8196 struct sched_group *sg, *prev;
8199 cpumask_clear(covered);
8200 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
8201 if (cpumask_empty(nodemask)) {
8202 sched_group_nodes[i] = NULL;
8206 sched_domain_node_span(i, domainspan);
8207 cpumask_and(domainspan, domainspan, cpu_map);
8209 sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
8212 printk(KERN_WARNING "Can not alloc domain group for "
8216 sched_group_nodes[i] = sg;
8217 for_each_cpu(j, nodemask) {
8218 struct sched_domain *sd;
8220 sd = &per_cpu(node_domains, j).sd;
8223 sg->__cpu_power = 0;
8224 cpumask_copy(sched_group_cpus(sg), nodemask);
8226 cpumask_or(covered, covered, nodemask);
8229 for (j = 0; j < nr_node_ids; j++) {
8230 int n = (i + j) % nr_node_ids;
8232 cpumask_complement(notcovered, covered);
8233 cpumask_and(tmpmask, notcovered, cpu_map);
8234 cpumask_and(tmpmask, tmpmask, domainspan);
8235 if (cpumask_empty(tmpmask))
8238 cpumask_and(tmpmask, tmpmask, cpumask_of_node(n));
8239 if (cpumask_empty(tmpmask))
8242 sg = kmalloc_node(sizeof(struct sched_group) +
8247 "Can not alloc domain group for node %d\n", j);
8250 sg->__cpu_power = 0;
8251 cpumask_copy(sched_group_cpus(sg), tmpmask);
8252 sg->next = prev->next;
8253 cpumask_or(covered, covered, tmpmask);
8260 /* Calculate CPU power for physical packages and nodes */
8261 #ifdef CONFIG_SCHED_SMT
8262 for_each_cpu(i, cpu_map) {
8263 struct sched_domain *sd = &per_cpu(cpu_domains, i).sd;
8265 init_sched_groups_power(i, sd);
8268 #ifdef CONFIG_SCHED_MC
8269 for_each_cpu(i, cpu_map) {
8270 struct sched_domain *sd = &per_cpu(core_domains, i).sd;
8272 init_sched_groups_power(i, sd);
8276 for_each_cpu(i, cpu_map) {
8277 struct sched_domain *sd = &per_cpu(phys_domains, i).sd;
8279 init_sched_groups_power(i, sd);
8283 for (i = 0; i < nr_node_ids; i++)
8284 init_numa_sched_groups_power(sched_group_nodes[i]);
8287 struct sched_group *sg;
8289 cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg,
8291 init_numa_sched_groups_power(sg);
8295 /* Attach the domains */
8296 for_each_cpu(i, cpu_map) {
8297 struct sched_domain *sd;
8298 #ifdef CONFIG_SCHED_SMT
8299 sd = &per_cpu(cpu_domains, i).sd;
8300 #elif defined(CONFIG_SCHED_MC)
8301 sd = &per_cpu(core_domains, i).sd;
8303 sd = &per_cpu(phys_domains, i).sd;
8305 cpu_attach_domain(sd, rd, i);
8311 free_cpumask_var(tmpmask);
8313 free_cpumask_var(send_covered);
8315 free_cpumask_var(this_core_map);
8316 free_this_sibling_map:
8317 free_cpumask_var(this_sibling_map);
8319 free_cpumask_var(nodemask);
8322 free_cpumask_var(notcovered);
8324 free_cpumask_var(covered);
8326 free_cpumask_var(domainspan);
8333 kfree(sched_group_nodes);
8339 free_sched_groups(cpu_map, tmpmask);
8340 free_rootdomain(rd);
8345 static int build_sched_domains(const struct cpumask *cpu_map)
8347 return __build_sched_domains(cpu_map, NULL);
8350 static struct cpumask *doms_cur; /* current sched domains */
8351 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
8352 static struct sched_domain_attr *dattr_cur;
8353 /* attribues of custom domains in 'doms_cur' */
8356 * Special case: If a kmalloc of a doms_cur partition (array of
8357 * cpumask) fails, then fallback to a single sched domain,
8358 * as determined by the single cpumask fallback_doms.
8360 static cpumask_var_t fallback_doms;
8363 * arch_update_cpu_topology lets virtualized architectures update the
8364 * cpu core maps. It is supposed to return 1 if the topology changed
8365 * or 0 if it stayed the same.
8367 int __attribute__((weak)) arch_update_cpu_topology(void)
8373 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8374 * For now this just excludes isolated cpus, but could be used to
8375 * exclude other special cases in the future.
8377 static int arch_init_sched_domains(const struct cpumask *cpu_map)
8381 arch_update_cpu_topology();
8383 doms_cur = kmalloc(cpumask_size(), GFP_KERNEL);
8385 doms_cur = fallback_doms;
8386 cpumask_andnot(doms_cur, cpu_map, cpu_isolated_map);
8388 err = build_sched_domains(doms_cur);
8389 register_sched_domain_sysctl();
8394 static void arch_destroy_sched_domains(const struct cpumask *cpu_map,
8395 struct cpumask *tmpmask)
8397 free_sched_groups(cpu_map, tmpmask);
8401 * Detach sched domains from a group of cpus specified in cpu_map
8402 * These cpus will now be attached to the NULL domain
8404 static void detach_destroy_domains(const struct cpumask *cpu_map)
8406 /* Save because hotplug lock held. */
8407 static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS);
8410 for_each_cpu(i, cpu_map)
8411 cpu_attach_domain(NULL, &def_root_domain, i);
8412 synchronize_sched();
8413 arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask));
8416 /* handle null as "default" */
8417 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
8418 struct sched_domain_attr *new, int idx_new)
8420 struct sched_domain_attr tmp;
8427 return !memcmp(cur ? (cur + idx_cur) : &tmp,
8428 new ? (new + idx_new) : &tmp,
8429 sizeof(struct sched_domain_attr));
8433 * Partition sched domains as specified by the 'ndoms_new'
8434 * cpumasks in the array doms_new[] of cpumasks. This compares
8435 * doms_new[] to the current sched domain partitioning, doms_cur[].
8436 * It destroys each deleted domain and builds each new domain.
8438 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8439 * The masks don't intersect (don't overlap.) We should setup one
8440 * sched domain for each mask. CPUs not in any of the cpumasks will
8441 * not be load balanced. If the same cpumask appears both in the
8442 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8445 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8446 * ownership of it and will kfree it when done with it. If the caller
8447 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8448 * ndoms_new == 1, and partition_sched_domains() will fallback to
8449 * the single partition 'fallback_doms', it also forces the domains
8452 * If doms_new == NULL it will be replaced with cpu_online_mask.
8453 * ndoms_new == 0 is a special case for destroying existing domains,
8454 * and it will not create the default domain.
8456 * Call with hotplug lock held
8458 /* FIXME: Change to struct cpumask *doms_new[] */
8459 void partition_sched_domains(int ndoms_new, struct cpumask *doms_new,
8460 struct sched_domain_attr *dattr_new)
8465 mutex_lock(&sched_domains_mutex);
8467 /* always unregister in case we don't destroy any domains */
8468 unregister_sched_domain_sysctl();
8470 /* Let architecture update cpu core mappings. */
8471 new_topology = arch_update_cpu_topology();
8473 n = doms_new ? ndoms_new : 0;
8475 /* Destroy deleted domains */
8476 for (i = 0; i < ndoms_cur; i++) {
8477 for (j = 0; j < n && !new_topology; j++) {
8478 if (cpumask_equal(&doms_cur[i], &doms_new[j])
8479 && dattrs_equal(dattr_cur, i, dattr_new, j))
8482 /* no match - a current sched domain not in new doms_new[] */
8483 detach_destroy_domains(doms_cur + i);
8488 if (doms_new == NULL) {
8490 doms_new = fallback_doms;
8491 cpumask_andnot(&doms_new[0], cpu_online_mask, cpu_isolated_map);
8492 WARN_ON_ONCE(dattr_new);
8495 /* Build new domains */
8496 for (i = 0; i < ndoms_new; i++) {
8497 for (j = 0; j < ndoms_cur && !new_topology; j++) {
8498 if (cpumask_equal(&doms_new[i], &doms_cur[j])
8499 && dattrs_equal(dattr_new, i, dattr_cur, j))
8502 /* no match - add a new doms_new */
8503 __build_sched_domains(doms_new + i,
8504 dattr_new ? dattr_new + i : NULL);
8509 /* Remember the new sched domains */
8510 if (doms_cur != fallback_doms)
8512 kfree(dattr_cur); /* kfree(NULL) is safe */
8513 doms_cur = doms_new;
8514 dattr_cur = dattr_new;
8515 ndoms_cur = ndoms_new;
8517 register_sched_domain_sysctl();
8519 mutex_unlock(&sched_domains_mutex);
8522 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8523 static void arch_reinit_sched_domains(void)
8527 /* Destroy domains first to force the rebuild */
8528 partition_sched_domains(0, NULL, NULL);
8530 rebuild_sched_domains();
8534 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
8536 unsigned int level = 0;
8538 if (sscanf(buf, "%u", &level) != 1)
8542 * level is always be positive so don't check for
8543 * level < POWERSAVINGS_BALANCE_NONE which is 0
8544 * What happens on 0 or 1 byte write,
8545 * need to check for count as well?
8548 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
8552 sched_smt_power_savings = level;
8554 sched_mc_power_savings = level;
8556 arch_reinit_sched_domains();
8561 #ifdef CONFIG_SCHED_MC
8562 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
8565 return sprintf(page, "%u\n", sched_mc_power_savings);
8567 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
8568 const char *buf, size_t count)
8570 return sched_power_savings_store(buf, count, 0);
8572 static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
8573 sched_mc_power_savings_show,
8574 sched_mc_power_savings_store);
8577 #ifdef CONFIG_SCHED_SMT
8578 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
8581 return sprintf(page, "%u\n", sched_smt_power_savings);
8583 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
8584 const char *buf, size_t count)
8586 return sched_power_savings_store(buf, count, 1);
8588 static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
8589 sched_smt_power_savings_show,
8590 sched_smt_power_savings_store);
8593 int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
8597 #ifdef CONFIG_SCHED_SMT
8599 err = sysfs_create_file(&cls->kset.kobj,
8600 &attr_sched_smt_power_savings.attr);
8602 #ifdef CONFIG_SCHED_MC
8603 if (!err && mc_capable())
8604 err = sysfs_create_file(&cls->kset.kobj,
8605 &attr_sched_mc_power_savings.attr);
8609 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
8611 #ifndef CONFIG_CPUSETS
8613 * Add online and remove offline CPUs from the scheduler domains.
8614 * When cpusets are enabled they take over this function.
8616 static int update_sched_domains(struct notifier_block *nfb,
8617 unsigned long action, void *hcpu)
8621 case CPU_ONLINE_FROZEN:
8623 case CPU_DEAD_FROZEN:
8624 partition_sched_domains(1, NULL, NULL);
8633 static int update_runtime(struct notifier_block *nfb,
8634 unsigned long action, void *hcpu)
8636 int cpu = (int)(long)hcpu;
8639 case CPU_DOWN_PREPARE:
8640 case CPU_DOWN_PREPARE_FROZEN:
8641 disable_runtime(cpu_rq(cpu));
8644 case CPU_DOWN_FAILED:
8645 case CPU_DOWN_FAILED_FROZEN:
8647 case CPU_ONLINE_FROZEN:
8648 enable_runtime(cpu_rq(cpu));
8656 void __init sched_init_smp(void)
8658 cpumask_var_t non_isolated_cpus;
8660 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
8662 #if defined(CONFIG_NUMA)
8663 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
8665 BUG_ON(sched_group_nodes_bycpu == NULL);
8668 mutex_lock(&sched_domains_mutex);
8669 arch_init_sched_domains(cpu_online_mask);
8670 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
8671 if (cpumask_empty(non_isolated_cpus))
8672 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
8673 mutex_unlock(&sched_domains_mutex);
8676 #ifndef CONFIG_CPUSETS
8677 /* XXX: Theoretical race here - CPU may be hotplugged now */
8678 hotcpu_notifier(update_sched_domains, 0);
8681 /* RT runtime code needs to handle some hotplug events */
8682 hotcpu_notifier(update_runtime, 0);
8686 /* Move init over to a non-isolated CPU */
8687 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
8689 sched_init_granularity();
8690 free_cpumask_var(non_isolated_cpus);
8692 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
8693 init_sched_rt_class();
8696 void __init sched_init_smp(void)
8698 sched_init_granularity();
8700 #endif /* CONFIG_SMP */
8702 int in_sched_functions(unsigned long addr)
8704 return in_lock_functions(addr) ||
8705 (addr >= (unsigned long)__sched_text_start
8706 && addr < (unsigned long)__sched_text_end);
8709 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
8711 cfs_rq->tasks_timeline = RB_ROOT;
8712 INIT_LIST_HEAD(&cfs_rq->tasks);
8713 #ifdef CONFIG_FAIR_GROUP_SCHED
8716 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
8719 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
8721 struct rt_prio_array *array;
8724 array = &rt_rq->active;
8725 for (i = 0; i < MAX_RT_PRIO; i++) {
8726 INIT_LIST_HEAD(array->queue + i);
8727 __clear_bit(i, array->bitmap);
8729 /* delimiter for bitsearch: */
8730 __set_bit(MAX_RT_PRIO, array->bitmap);
8732 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8733 rt_rq->highest_prio.curr = MAX_RT_PRIO;
8735 rt_rq->highest_prio.next = MAX_RT_PRIO;
8739 rt_rq->rt_nr_migratory = 0;
8740 rt_rq->overloaded = 0;
8741 plist_head_init(&rq->rt.pushable_tasks, &rq->lock);
8745 rt_rq->rt_throttled = 0;
8746 rt_rq->rt_runtime = 0;
8747 spin_lock_init(&rt_rq->rt_runtime_lock);
8749 #ifdef CONFIG_RT_GROUP_SCHED
8750 rt_rq->rt_nr_boosted = 0;
8755 #ifdef CONFIG_FAIR_GROUP_SCHED
8756 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
8757 struct sched_entity *se, int cpu, int add,
8758 struct sched_entity *parent)
8760 struct rq *rq = cpu_rq(cpu);
8761 tg->cfs_rq[cpu] = cfs_rq;
8762 init_cfs_rq(cfs_rq, rq);
8765 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
8768 /* se could be NULL for init_task_group */
8773 se->cfs_rq = &rq->cfs;
8775 se->cfs_rq = parent->my_q;
8778 se->load.weight = tg->shares;
8779 se->load.inv_weight = 0;
8780 se->parent = parent;
8784 #ifdef CONFIG_RT_GROUP_SCHED
8785 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
8786 struct sched_rt_entity *rt_se, int cpu, int add,
8787 struct sched_rt_entity *parent)
8789 struct rq *rq = cpu_rq(cpu);
8791 tg->rt_rq[cpu] = rt_rq;
8792 init_rt_rq(rt_rq, rq);
8794 rt_rq->rt_se = rt_se;
8795 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
8797 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
8799 tg->rt_se[cpu] = rt_se;
8804 rt_se->rt_rq = &rq->rt;
8806 rt_se->rt_rq = parent->my_q;
8808 rt_se->my_q = rt_rq;
8809 rt_se->parent = parent;
8810 INIT_LIST_HEAD(&rt_se->run_list);
8814 void __init sched_init(void)
8817 unsigned long alloc_size = 0, ptr;
8819 #ifdef CONFIG_FAIR_GROUP_SCHED
8820 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8822 #ifdef CONFIG_RT_GROUP_SCHED
8823 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8825 #ifdef CONFIG_USER_SCHED
8828 #ifdef CONFIG_CPUMASK_OFFSTACK
8829 alloc_size += num_possible_cpus() * cpumask_size();
8832 * As sched_init() is called before page_alloc is setup,
8833 * we use alloc_bootmem().
8836 ptr = (unsigned long)alloc_bootmem(alloc_size);
8838 #ifdef CONFIG_FAIR_GROUP_SCHED
8839 init_task_group.se = (struct sched_entity **)ptr;
8840 ptr += nr_cpu_ids * sizeof(void **);
8842 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
8843 ptr += nr_cpu_ids * sizeof(void **);
8845 #ifdef CONFIG_USER_SCHED
8846 root_task_group.se = (struct sched_entity **)ptr;
8847 ptr += nr_cpu_ids * sizeof(void **);
8849 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
8850 ptr += nr_cpu_ids * sizeof(void **);
8851 #endif /* CONFIG_USER_SCHED */
8852 #endif /* CONFIG_FAIR_GROUP_SCHED */
8853 #ifdef CONFIG_RT_GROUP_SCHED
8854 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
8855 ptr += nr_cpu_ids * sizeof(void **);
8857 init_task_group.rt_rq = (struct rt_rq **)ptr;
8858 ptr += nr_cpu_ids * sizeof(void **);
8860 #ifdef CONFIG_USER_SCHED
8861 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
8862 ptr += nr_cpu_ids * sizeof(void **);
8864 root_task_group.rt_rq = (struct rt_rq **)ptr;
8865 ptr += nr_cpu_ids * sizeof(void **);
8866 #endif /* CONFIG_USER_SCHED */
8867 #endif /* CONFIG_RT_GROUP_SCHED */
8868 #ifdef CONFIG_CPUMASK_OFFSTACK
8869 for_each_possible_cpu(i) {
8870 per_cpu(load_balance_tmpmask, i) = (void *)ptr;
8871 ptr += cpumask_size();
8873 #endif /* CONFIG_CPUMASK_OFFSTACK */
8877 init_defrootdomain();
8880 init_rt_bandwidth(&def_rt_bandwidth,
8881 global_rt_period(), global_rt_runtime());
8883 #ifdef CONFIG_RT_GROUP_SCHED
8884 init_rt_bandwidth(&init_task_group.rt_bandwidth,
8885 global_rt_period(), global_rt_runtime());
8886 #ifdef CONFIG_USER_SCHED
8887 init_rt_bandwidth(&root_task_group.rt_bandwidth,
8888 global_rt_period(), RUNTIME_INF);
8889 #endif /* CONFIG_USER_SCHED */
8890 #endif /* CONFIG_RT_GROUP_SCHED */
8892 #ifdef CONFIG_GROUP_SCHED
8893 list_add(&init_task_group.list, &task_groups);
8894 INIT_LIST_HEAD(&init_task_group.children);
8896 #ifdef CONFIG_USER_SCHED
8897 INIT_LIST_HEAD(&root_task_group.children);
8898 init_task_group.parent = &root_task_group;
8899 list_add(&init_task_group.siblings, &root_task_group.children);
8900 #endif /* CONFIG_USER_SCHED */
8901 #endif /* CONFIG_GROUP_SCHED */
8903 for_each_possible_cpu(i) {
8907 spin_lock_init(&rq->lock);
8909 init_cfs_rq(&rq->cfs, rq);
8910 init_rt_rq(&rq->rt, rq);
8911 #ifdef CONFIG_FAIR_GROUP_SCHED
8912 init_task_group.shares = init_task_group_load;
8913 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
8914 #ifdef CONFIG_CGROUP_SCHED
8916 * How much cpu bandwidth does init_task_group get?
8918 * In case of task-groups formed thr' the cgroup filesystem, it
8919 * gets 100% of the cpu resources in the system. This overall
8920 * system cpu resource is divided among the tasks of
8921 * init_task_group and its child task-groups in a fair manner,
8922 * based on each entity's (task or task-group's) weight
8923 * (se->load.weight).
8925 * In other words, if init_task_group has 10 tasks of weight
8926 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8927 * then A0's share of the cpu resource is:
8929 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8931 * We achieve this by letting init_task_group's tasks sit
8932 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8934 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
8935 #elif defined CONFIG_USER_SCHED
8936 root_task_group.shares = NICE_0_LOAD;
8937 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
8939 * In case of task-groups formed thr' the user id of tasks,
8940 * init_task_group represents tasks belonging to root user.
8941 * Hence it forms a sibling of all subsequent groups formed.
8942 * In this case, init_task_group gets only a fraction of overall
8943 * system cpu resource, based on the weight assigned to root
8944 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8945 * by letting tasks of init_task_group sit in a separate cfs_rq
8946 * (init_cfs_rq) and having one entity represent this group of
8947 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8949 init_tg_cfs_entry(&init_task_group,
8950 &per_cpu(init_cfs_rq, i),
8951 &per_cpu(init_sched_entity, i), i, 1,
8952 root_task_group.se[i]);
8955 #endif /* CONFIG_FAIR_GROUP_SCHED */
8957 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
8958 #ifdef CONFIG_RT_GROUP_SCHED
8959 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
8960 #ifdef CONFIG_CGROUP_SCHED
8961 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
8962 #elif defined CONFIG_USER_SCHED
8963 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
8964 init_tg_rt_entry(&init_task_group,
8965 &per_cpu(init_rt_rq, i),
8966 &per_cpu(init_sched_rt_entity, i), i, 1,
8967 root_task_group.rt_se[i]);
8971 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
8972 rq->cpu_load[j] = 0;
8976 rq->active_balance = 0;
8977 rq->next_balance = jiffies;
8981 rq->migration_thread = NULL;
8982 INIT_LIST_HEAD(&rq->migration_queue);
8983 rq_attach_root(rq, &def_root_domain);
8986 atomic_set(&rq->nr_iowait, 0);
8989 set_load_weight(&init_task);
8991 #ifdef CONFIG_PREEMPT_NOTIFIERS
8992 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
8996 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
8999 #ifdef CONFIG_RT_MUTEXES
9000 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
9004 * The boot idle thread does lazy MMU switching as well:
9006 atomic_inc(&init_mm.mm_count);
9007 enter_lazy_tlb(&init_mm, current);
9010 * Make us the idle thread. Technically, schedule() should not be
9011 * called from this thread, however somewhere below it might be,
9012 * but because we are the idle thread, we just pick up running again
9013 * when this runqueue becomes "idle".
9015 init_idle(current, smp_processor_id());
9017 * During early bootup we pretend to be a normal task:
9019 current->sched_class = &fair_sched_class;
9021 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9022 alloc_bootmem_cpumask_var(&nohz_cpu_mask);
9025 alloc_bootmem_cpumask_var(&nohz.cpu_mask);
9027 alloc_bootmem_cpumask_var(&cpu_isolated_map);
9030 scheduler_running = 1;
9033 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9034 void __might_sleep(char *file, int line)
9037 static unsigned long prev_jiffy; /* ratelimiting */
9039 if ((!in_atomic() && !irqs_disabled()) ||
9040 system_state != SYSTEM_RUNNING || oops_in_progress)
9042 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
9044 prev_jiffy = jiffies;
9047 "BUG: sleeping function called from invalid context at %s:%d\n",
9050 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9051 in_atomic(), irqs_disabled(),
9052 current->pid, current->comm);
9054 debug_show_held_locks(current);
9055 if (irqs_disabled())
9056 print_irqtrace_events(current);
9060 EXPORT_SYMBOL(__might_sleep);
9063 #ifdef CONFIG_MAGIC_SYSRQ
9064 static void normalize_task(struct rq *rq, struct task_struct *p)
9068 update_rq_clock(rq);
9069 on_rq = p->se.on_rq;
9071 deactivate_task(rq, p, 0);
9072 __setscheduler(rq, p, SCHED_NORMAL, 0);
9074 activate_task(rq, p, 0);
9075 resched_task(rq->curr);
9079 void normalize_rt_tasks(void)
9081 struct task_struct *g, *p;
9082 unsigned long flags;
9085 read_lock_irqsave(&tasklist_lock, flags);
9086 do_each_thread(g, p) {
9088 * Only normalize user tasks:
9093 p->se.exec_start = 0;
9094 #ifdef CONFIG_SCHEDSTATS
9095 p->se.wait_start = 0;
9096 p->se.sleep_start = 0;
9097 p->se.block_start = 0;
9102 * Renice negative nice level userspace
9105 if (TASK_NICE(p) < 0 && p->mm)
9106 set_user_nice(p, 0);
9110 spin_lock(&p->pi_lock);
9111 rq = __task_rq_lock(p);
9113 normalize_task(rq, p);
9115 __task_rq_unlock(rq);
9116 spin_unlock(&p->pi_lock);
9117 } while_each_thread(g, p);
9119 read_unlock_irqrestore(&tasklist_lock, flags);
9122 #endif /* CONFIG_MAGIC_SYSRQ */
9126 * These functions are only useful for the IA64 MCA handling.
9128 * They can only be called when the whole system has been
9129 * stopped - every CPU needs to be quiescent, and no scheduling
9130 * activity can take place. Using them for anything else would
9131 * be a serious bug, and as a result, they aren't even visible
9132 * under any other configuration.
9136 * curr_task - return the current task for a given cpu.
9137 * @cpu: the processor in question.
9139 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9141 struct task_struct *curr_task(int cpu)
9143 return cpu_curr(cpu);
9147 * set_curr_task - set the current task for a given cpu.
9148 * @cpu: the processor in question.
9149 * @p: the task pointer to set.
9151 * Description: This function must only be used when non-maskable interrupts
9152 * are serviced on a separate stack. It allows the architecture to switch the
9153 * notion of the current task on a cpu in a non-blocking manner. This function
9154 * must be called with all CPU's synchronized, and interrupts disabled, the
9155 * and caller must save the original value of the current task (see
9156 * curr_task() above) and restore that value before reenabling interrupts and
9157 * re-starting the system.
9159 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9161 void set_curr_task(int cpu, struct task_struct *p)
9168 #ifdef CONFIG_FAIR_GROUP_SCHED
9169 static void free_fair_sched_group(struct task_group *tg)
9173 for_each_possible_cpu(i) {
9175 kfree(tg->cfs_rq[i]);
9185 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
9187 struct cfs_rq *cfs_rq;
9188 struct sched_entity *se;
9192 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
9195 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
9199 tg->shares = NICE_0_LOAD;
9201 for_each_possible_cpu(i) {
9204 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
9205 GFP_KERNEL, cpu_to_node(i));
9209 se = kzalloc_node(sizeof(struct sched_entity),
9210 GFP_KERNEL, cpu_to_node(i));
9214 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
9223 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
9225 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
9226 &cpu_rq(cpu)->leaf_cfs_rq_list);
9229 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
9231 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
9233 #else /* !CONFG_FAIR_GROUP_SCHED */
9234 static inline void free_fair_sched_group(struct task_group *tg)
9239 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
9244 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
9248 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
9251 #endif /* CONFIG_FAIR_GROUP_SCHED */
9253 #ifdef CONFIG_RT_GROUP_SCHED
9254 static void free_rt_sched_group(struct task_group *tg)
9258 destroy_rt_bandwidth(&tg->rt_bandwidth);
9260 for_each_possible_cpu(i) {
9262 kfree(tg->rt_rq[i]);
9264 kfree(tg->rt_se[i]);
9272 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
9274 struct rt_rq *rt_rq;
9275 struct sched_rt_entity *rt_se;
9279 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
9282 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
9286 init_rt_bandwidth(&tg->rt_bandwidth,
9287 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
9289 for_each_possible_cpu(i) {
9292 rt_rq = kzalloc_node(sizeof(struct rt_rq),
9293 GFP_KERNEL, cpu_to_node(i));
9297 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
9298 GFP_KERNEL, cpu_to_node(i));
9302 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
9311 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
9313 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
9314 &cpu_rq(cpu)->leaf_rt_rq_list);
9317 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
9319 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
9321 #else /* !CONFIG_RT_GROUP_SCHED */
9322 static inline void free_rt_sched_group(struct task_group *tg)
9327 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
9332 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
9336 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
9339 #endif /* CONFIG_RT_GROUP_SCHED */
9341 #ifdef CONFIG_GROUP_SCHED
9342 static void free_sched_group(struct task_group *tg)
9344 free_fair_sched_group(tg);
9345 free_rt_sched_group(tg);
9349 /* allocate runqueue etc for a new task group */
9350 struct task_group *sched_create_group(struct task_group *parent)
9352 struct task_group *tg;
9353 unsigned long flags;
9356 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
9358 return ERR_PTR(-ENOMEM);
9360 if (!alloc_fair_sched_group(tg, parent))
9363 if (!alloc_rt_sched_group(tg, parent))
9366 spin_lock_irqsave(&task_group_lock, flags);
9367 for_each_possible_cpu(i) {
9368 register_fair_sched_group(tg, i);
9369 register_rt_sched_group(tg, i);
9371 list_add_rcu(&tg->list, &task_groups);
9373 WARN_ON(!parent); /* root should already exist */
9375 tg->parent = parent;
9376 INIT_LIST_HEAD(&tg->children);
9377 list_add_rcu(&tg->siblings, &parent->children);
9378 spin_unlock_irqrestore(&task_group_lock, flags);
9383 free_sched_group(tg);
9384 return ERR_PTR(-ENOMEM);
9387 /* rcu callback to free various structures associated with a task group */
9388 static void free_sched_group_rcu(struct rcu_head *rhp)
9390 /* now it should be safe to free those cfs_rqs */
9391 free_sched_group(container_of(rhp, struct task_group, rcu));
9394 /* Destroy runqueue etc associated with a task group */
9395 void sched_destroy_group(struct task_group *tg)
9397 unsigned long flags;
9400 spin_lock_irqsave(&task_group_lock, flags);
9401 for_each_possible_cpu(i) {
9402 unregister_fair_sched_group(tg, i);
9403 unregister_rt_sched_group(tg, i);
9405 list_del_rcu(&tg->list);
9406 list_del_rcu(&tg->siblings);
9407 spin_unlock_irqrestore(&task_group_lock, flags);
9409 /* wait for possible concurrent references to cfs_rqs complete */
9410 call_rcu(&tg->rcu, free_sched_group_rcu);
9413 /* change task's runqueue when it moves between groups.
9414 * The caller of this function should have put the task in its new group
9415 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
9416 * reflect its new group.
9418 void sched_move_task(struct task_struct *tsk)
9421 unsigned long flags;
9424 rq = task_rq_lock(tsk, &flags);
9426 update_rq_clock(rq);
9428 running = task_current(rq, tsk);
9429 on_rq = tsk->se.on_rq;
9432 dequeue_task(rq, tsk, 0);
9433 if (unlikely(running))
9434 tsk->sched_class->put_prev_task(rq, tsk);
9436 set_task_rq(tsk, task_cpu(tsk));
9438 #ifdef CONFIG_FAIR_GROUP_SCHED
9439 if (tsk->sched_class->moved_group)
9440 tsk->sched_class->moved_group(tsk);
9443 if (unlikely(running))
9444 tsk->sched_class->set_curr_task(rq);
9446 enqueue_task(rq, tsk, 0);
9448 task_rq_unlock(rq, &flags);
9450 #endif /* CONFIG_GROUP_SCHED */
9452 #ifdef CONFIG_FAIR_GROUP_SCHED
9453 static void __set_se_shares(struct sched_entity *se, unsigned long shares)
9455 struct cfs_rq *cfs_rq = se->cfs_rq;
9460 dequeue_entity(cfs_rq, se, 0);
9462 se->load.weight = shares;
9463 se->load.inv_weight = 0;
9466 enqueue_entity(cfs_rq, se, 0);
9469 static void set_se_shares(struct sched_entity *se, unsigned long shares)
9471 struct cfs_rq *cfs_rq = se->cfs_rq;
9472 struct rq *rq = cfs_rq->rq;
9473 unsigned long flags;
9475 spin_lock_irqsave(&rq->lock, flags);
9476 __set_se_shares(se, shares);
9477 spin_unlock_irqrestore(&rq->lock, flags);
9480 static DEFINE_MUTEX(shares_mutex);
9482 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
9485 unsigned long flags;
9488 * We can't change the weight of the root cgroup.
9493 if (shares < MIN_SHARES)
9494 shares = MIN_SHARES;
9495 else if (shares > MAX_SHARES)
9496 shares = MAX_SHARES;
9498 mutex_lock(&shares_mutex);
9499 if (tg->shares == shares)
9502 spin_lock_irqsave(&task_group_lock, flags);
9503 for_each_possible_cpu(i)
9504 unregister_fair_sched_group(tg, i);
9505 list_del_rcu(&tg->siblings);
9506 spin_unlock_irqrestore(&task_group_lock, flags);
9508 /* wait for any ongoing reference to this group to finish */
9509 synchronize_sched();
9512 * Now we are free to modify the group's share on each cpu
9513 * w/o tripping rebalance_share or load_balance_fair.
9515 tg->shares = shares;
9516 for_each_possible_cpu(i) {
9520 cfs_rq_set_shares(tg->cfs_rq[i], 0);
9521 set_se_shares(tg->se[i], shares);
9525 * Enable load balance activity on this group, by inserting it back on
9526 * each cpu's rq->leaf_cfs_rq_list.
9528 spin_lock_irqsave(&task_group_lock, flags);
9529 for_each_possible_cpu(i)
9530 register_fair_sched_group(tg, i);
9531 list_add_rcu(&tg->siblings, &tg->parent->children);
9532 spin_unlock_irqrestore(&task_group_lock, flags);
9534 mutex_unlock(&shares_mutex);
9538 unsigned long sched_group_shares(struct task_group *tg)
9544 #ifdef CONFIG_RT_GROUP_SCHED
9546 * Ensure that the real time constraints are schedulable.
9548 static DEFINE_MUTEX(rt_constraints_mutex);
9550 static unsigned long to_ratio(u64 period, u64 runtime)
9552 if (runtime == RUNTIME_INF)
9555 return div64_u64(runtime << 20, period);
9558 /* Must be called with tasklist_lock held */
9559 static inline int tg_has_rt_tasks(struct task_group *tg)
9561 struct task_struct *g, *p;
9563 do_each_thread(g, p) {
9564 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
9566 } while_each_thread(g, p);
9571 struct rt_schedulable_data {
9572 struct task_group *tg;
9577 static int tg_schedulable(struct task_group *tg, void *data)
9579 struct rt_schedulable_data *d = data;
9580 struct task_group *child;
9581 unsigned long total, sum = 0;
9582 u64 period, runtime;
9584 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
9585 runtime = tg->rt_bandwidth.rt_runtime;
9588 period = d->rt_period;
9589 runtime = d->rt_runtime;
9592 #ifdef CONFIG_USER_SCHED
9593 if (tg == &root_task_group) {
9594 period = global_rt_period();
9595 runtime = global_rt_runtime();
9600 * Cannot have more runtime than the period.
9602 if (runtime > period && runtime != RUNTIME_INF)
9606 * Ensure we don't starve existing RT tasks.
9608 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
9611 total = to_ratio(period, runtime);
9614 * Nobody can have more than the global setting allows.
9616 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
9620 * The sum of our children's runtime should not exceed our own.
9622 list_for_each_entry_rcu(child, &tg->children, siblings) {
9623 period = ktime_to_ns(child->rt_bandwidth.rt_period);
9624 runtime = child->rt_bandwidth.rt_runtime;
9626 if (child == d->tg) {
9627 period = d->rt_period;
9628 runtime = d->rt_runtime;
9631 sum += to_ratio(period, runtime);
9640 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
9642 struct rt_schedulable_data data = {
9644 .rt_period = period,
9645 .rt_runtime = runtime,
9648 return walk_tg_tree(tg_schedulable, tg_nop, &data);
9651 static int tg_set_bandwidth(struct task_group *tg,
9652 u64 rt_period, u64 rt_runtime)
9656 mutex_lock(&rt_constraints_mutex);
9657 read_lock(&tasklist_lock);
9658 err = __rt_schedulable(tg, rt_period, rt_runtime);
9662 spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
9663 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
9664 tg->rt_bandwidth.rt_runtime = rt_runtime;
9666 for_each_possible_cpu(i) {
9667 struct rt_rq *rt_rq = tg->rt_rq[i];
9669 spin_lock(&rt_rq->rt_runtime_lock);
9670 rt_rq->rt_runtime = rt_runtime;
9671 spin_unlock(&rt_rq->rt_runtime_lock);
9673 spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
9675 read_unlock(&tasklist_lock);
9676 mutex_unlock(&rt_constraints_mutex);
9681 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
9683 u64 rt_runtime, rt_period;
9685 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
9686 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
9687 if (rt_runtime_us < 0)
9688 rt_runtime = RUNTIME_INF;
9690 return tg_set_bandwidth(tg, rt_period, rt_runtime);
9693 long sched_group_rt_runtime(struct task_group *tg)
9697 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
9700 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
9701 do_div(rt_runtime_us, NSEC_PER_USEC);
9702 return rt_runtime_us;
9705 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
9707 u64 rt_runtime, rt_period;
9709 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
9710 rt_runtime = tg->rt_bandwidth.rt_runtime;
9715 return tg_set_bandwidth(tg, rt_period, rt_runtime);
9718 long sched_group_rt_period(struct task_group *tg)
9722 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
9723 do_div(rt_period_us, NSEC_PER_USEC);
9724 return rt_period_us;
9727 static int sched_rt_global_constraints(void)
9729 u64 runtime, period;
9732 if (sysctl_sched_rt_period <= 0)
9735 runtime = global_rt_runtime();
9736 period = global_rt_period();
9739 * Sanity check on the sysctl variables.
9741 if (runtime > period && runtime != RUNTIME_INF)
9744 mutex_lock(&rt_constraints_mutex);
9745 read_lock(&tasklist_lock);
9746 ret = __rt_schedulable(NULL, 0, 0);
9747 read_unlock(&tasklist_lock);
9748 mutex_unlock(&rt_constraints_mutex);
9753 int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
9755 /* Don't accept realtime tasks when there is no way for them to run */
9756 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
9762 #else /* !CONFIG_RT_GROUP_SCHED */
9763 static int sched_rt_global_constraints(void)
9765 unsigned long flags;
9768 if (sysctl_sched_rt_period <= 0)
9771 spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
9772 for_each_possible_cpu(i) {
9773 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
9775 spin_lock(&rt_rq->rt_runtime_lock);
9776 rt_rq->rt_runtime = global_rt_runtime();
9777 spin_unlock(&rt_rq->rt_runtime_lock);
9779 spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
9783 #endif /* CONFIG_RT_GROUP_SCHED */
9785 int sched_rt_handler(struct ctl_table *table, int write,
9786 struct file *filp, void __user *buffer, size_t *lenp,
9790 int old_period, old_runtime;
9791 static DEFINE_MUTEX(mutex);
9794 old_period = sysctl_sched_rt_period;
9795 old_runtime = sysctl_sched_rt_runtime;
9797 ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
9799 if (!ret && write) {
9800 ret = sched_rt_global_constraints();
9802 sysctl_sched_rt_period = old_period;
9803 sysctl_sched_rt_runtime = old_runtime;
9805 def_rt_bandwidth.rt_runtime = global_rt_runtime();
9806 def_rt_bandwidth.rt_period =
9807 ns_to_ktime(global_rt_period());
9810 mutex_unlock(&mutex);
9815 #ifdef CONFIG_CGROUP_SCHED
9817 /* return corresponding task_group object of a cgroup */
9818 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
9820 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
9821 struct task_group, css);
9824 static struct cgroup_subsys_state *
9825 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
9827 struct task_group *tg, *parent;
9829 if (!cgrp->parent) {
9830 /* This is early initialization for the top cgroup */
9831 return &init_task_group.css;
9834 parent = cgroup_tg(cgrp->parent);
9835 tg = sched_create_group(parent);
9837 return ERR_PTR(-ENOMEM);
9843 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
9845 struct task_group *tg = cgroup_tg(cgrp);
9847 sched_destroy_group(tg);
9851 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9852 struct task_struct *tsk)
9854 #ifdef CONFIG_RT_GROUP_SCHED
9855 if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
9858 /* We don't support RT-tasks being in separate groups */
9859 if (tsk->sched_class != &fair_sched_class)
9867 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9868 struct cgroup *old_cont, struct task_struct *tsk)
9870 sched_move_task(tsk);
9873 #ifdef CONFIG_FAIR_GROUP_SCHED
9874 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
9877 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
9880 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
9882 struct task_group *tg = cgroup_tg(cgrp);
9884 return (u64) tg->shares;
9886 #endif /* CONFIG_FAIR_GROUP_SCHED */
9888 #ifdef CONFIG_RT_GROUP_SCHED
9889 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
9892 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
9895 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
9897 return sched_group_rt_runtime(cgroup_tg(cgrp));
9900 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
9903 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
9906 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
9908 return sched_group_rt_period(cgroup_tg(cgrp));
9910 #endif /* CONFIG_RT_GROUP_SCHED */
9912 static struct cftype cpu_files[] = {
9913 #ifdef CONFIG_FAIR_GROUP_SCHED
9916 .read_u64 = cpu_shares_read_u64,
9917 .write_u64 = cpu_shares_write_u64,
9920 #ifdef CONFIG_RT_GROUP_SCHED
9922 .name = "rt_runtime_us",
9923 .read_s64 = cpu_rt_runtime_read,
9924 .write_s64 = cpu_rt_runtime_write,
9927 .name = "rt_period_us",
9928 .read_u64 = cpu_rt_period_read_uint,
9929 .write_u64 = cpu_rt_period_write_uint,
9934 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
9936 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
9939 struct cgroup_subsys cpu_cgroup_subsys = {
9941 .create = cpu_cgroup_create,
9942 .destroy = cpu_cgroup_destroy,
9943 .can_attach = cpu_cgroup_can_attach,
9944 .attach = cpu_cgroup_attach,
9945 .populate = cpu_cgroup_populate,
9946 .subsys_id = cpu_cgroup_subsys_id,
9950 #endif /* CONFIG_CGROUP_SCHED */
9952 #ifdef CONFIG_CGROUP_CPUACCT
9955 * CPU accounting code for task groups.
9957 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9958 * (balbir@in.ibm.com).
9961 /* track cpu usage of a group of tasks and its child groups */
9963 struct cgroup_subsys_state css;
9964 /* cpuusage holds pointer to a u64-type object on every cpu */
9966 struct cpuacct *parent;
9969 struct cgroup_subsys cpuacct_subsys;
9971 /* return cpu accounting group corresponding to this container */
9972 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
9974 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
9975 struct cpuacct, css);
9978 /* return cpu accounting group to which this task belongs */
9979 static inline struct cpuacct *task_ca(struct task_struct *tsk)
9981 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
9982 struct cpuacct, css);
9985 /* create a new cpu accounting group */
9986 static struct cgroup_subsys_state *cpuacct_create(
9987 struct cgroup_subsys *ss, struct cgroup *cgrp)
9989 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
9992 return ERR_PTR(-ENOMEM);
9994 ca->cpuusage = alloc_percpu(u64);
9995 if (!ca->cpuusage) {
9997 return ERR_PTR(-ENOMEM);
10001 ca->parent = cgroup_ca(cgrp->parent);
10006 /* destroy an existing cpu accounting group */
10008 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
10010 struct cpuacct *ca = cgroup_ca(cgrp);
10012 free_percpu(ca->cpuusage);
10016 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
10018 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10021 #ifndef CONFIG_64BIT
10023 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10025 spin_lock_irq(&cpu_rq(cpu)->lock);
10027 spin_unlock_irq(&cpu_rq(cpu)->lock);
10035 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
10037 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10039 #ifndef CONFIG_64BIT
10041 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10043 spin_lock_irq(&cpu_rq(cpu)->lock);
10045 spin_unlock_irq(&cpu_rq(cpu)->lock);
10051 /* return total cpu usage (in nanoseconds) of a group */
10052 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
10054 struct cpuacct *ca = cgroup_ca(cgrp);
10055 u64 totalcpuusage = 0;
10058 for_each_present_cpu(i)
10059 totalcpuusage += cpuacct_cpuusage_read(ca, i);
10061 return totalcpuusage;
10064 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
10067 struct cpuacct *ca = cgroup_ca(cgrp);
10076 for_each_present_cpu(i)
10077 cpuacct_cpuusage_write(ca, i, 0);
10083 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
10084 struct seq_file *m)
10086 struct cpuacct *ca = cgroup_ca(cgroup);
10090 for_each_present_cpu(i) {
10091 percpu = cpuacct_cpuusage_read(ca, i);
10092 seq_printf(m, "%llu ", (unsigned long long) percpu);
10094 seq_printf(m, "\n");
10098 static struct cftype files[] = {
10101 .read_u64 = cpuusage_read,
10102 .write_u64 = cpuusage_write,
10105 .name = "usage_percpu",
10106 .read_seq_string = cpuacct_percpu_seq_read,
10111 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
10113 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
10117 * charge this task's execution time to its accounting group.
10119 * called with rq->lock held.
10121 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
10123 struct cpuacct *ca;
10126 if (unlikely(!cpuacct_subsys.active))
10129 cpu = task_cpu(tsk);
10132 for (; ca; ca = ca->parent) {
10133 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10134 *cpuusage += cputime;
10138 struct cgroup_subsys cpuacct_subsys = {
10140 .create = cpuacct_create,
10141 .destroy = cpuacct_destroy,
10142 .populate = cpuacct_populate,
10143 .subsys_id = cpuacct_subsys_id,
10145 #endif /* CONFIG_CGROUP_CPUACCT */