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_PINNED, 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;
591 #ifdef CONFIG_FAIR_GROUP_SCHED
592 /* list of leaf cfs_rq on this cpu: */
593 struct list_head leaf_cfs_rq_list;
595 #ifdef CONFIG_RT_GROUP_SCHED
596 struct list_head leaf_rt_rq_list;
600 * This is part of a global counter where only the total sum
601 * over all CPUs matters. A task can increase this counter on
602 * one CPU and if it got migrated afterwards it may decrease
603 * it on another CPU. Always updated under the runqueue lock:
605 unsigned long nr_uninterruptible;
607 struct task_struct *curr, *idle;
608 unsigned long next_balance;
609 struct mm_struct *prev_mm;
616 struct root_domain *rd;
617 struct sched_domain *sd;
619 unsigned char idle_at_tick;
620 /* For active balancing */
623 /* cpu of this runqueue: */
627 unsigned long avg_load_per_task;
629 struct task_struct *migration_thread;
630 struct list_head migration_queue;
633 #ifdef CONFIG_SCHED_HRTICK
635 int hrtick_csd_pending;
636 struct call_single_data hrtick_csd;
638 struct hrtimer hrtick_timer;
641 #ifdef CONFIG_SCHEDSTATS
643 struct sched_info rq_sched_info;
644 unsigned long long rq_cpu_time;
645 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
647 /* sys_sched_yield() stats */
648 unsigned int yld_count;
650 /* schedule() stats */
651 unsigned int sched_switch;
652 unsigned int sched_count;
653 unsigned int sched_goidle;
655 /* try_to_wake_up() stats */
656 unsigned int ttwu_count;
657 unsigned int ttwu_local;
660 unsigned int bkl_count;
664 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
666 static inline void check_preempt_curr(struct rq *rq, struct task_struct *p, int sync)
668 rq->curr->sched_class->check_preempt_curr(rq, p, sync);
671 static inline int cpu_of(struct rq *rq)
681 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
682 * See detach_destroy_domains: synchronize_sched for details.
684 * The domain tree of any CPU may only be accessed from within
685 * preempt-disabled sections.
687 #define for_each_domain(cpu, __sd) \
688 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
690 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
691 #define this_rq() (&__get_cpu_var(runqueues))
692 #define task_rq(p) cpu_rq(task_cpu(p))
693 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
695 static inline void update_rq_clock(struct rq *rq)
697 rq->clock = sched_clock_cpu(cpu_of(rq));
701 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
703 #ifdef CONFIG_SCHED_DEBUG
704 # define const_debug __read_mostly
706 # define const_debug static const
712 * Returns true if the current cpu runqueue is locked.
713 * This interface allows printk to be called with the runqueue lock
714 * held and know whether or not it is OK to wake up the klogd.
716 int runqueue_is_locked(void)
719 struct rq *rq = cpu_rq(cpu);
722 ret = spin_is_locked(&rq->lock);
728 * Debugging: various feature bits
731 #define SCHED_FEAT(name, enabled) \
732 __SCHED_FEAT_##name ,
735 #include "sched_features.h"
740 #define SCHED_FEAT(name, enabled) \
741 (1UL << __SCHED_FEAT_##name) * enabled |
743 const_debug unsigned int sysctl_sched_features =
744 #include "sched_features.h"
749 #ifdef CONFIG_SCHED_DEBUG
750 #define SCHED_FEAT(name, enabled) \
753 static __read_mostly char *sched_feat_names[] = {
754 #include "sched_features.h"
760 static int sched_feat_show(struct seq_file *m, void *v)
764 for (i = 0; sched_feat_names[i]; i++) {
765 if (!(sysctl_sched_features & (1UL << i)))
767 seq_printf(m, "%s ", sched_feat_names[i]);
775 sched_feat_write(struct file *filp, const char __user *ubuf,
776 size_t cnt, loff_t *ppos)
786 if (copy_from_user(&buf, ubuf, cnt))
791 if (strncmp(buf, "NO_", 3) == 0) {
796 for (i = 0; sched_feat_names[i]; i++) {
797 int len = strlen(sched_feat_names[i]);
799 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
801 sysctl_sched_features &= ~(1UL << i);
803 sysctl_sched_features |= (1UL << i);
808 if (!sched_feat_names[i])
816 static int sched_feat_open(struct inode *inode, struct file *filp)
818 return single_open(filp, sched_feat_show, NULL);
821 static struct file_operations sched_feat_fops = {
822 .open = sched_feat_open,
823 .write = sched_feat_write,
826 .release = single_release,
829 static __init int sched_init_debug(void)
831 debugfs_create_file("sched_features", 0644, NULL, NULL,
836 late_initcall(sched_init_debug);
840 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
843 * Number of tasks to iterate in a single balance run.
844 * Limited because this is done with IRQs disabled.
846 const_debug unsigned int sysctl_sched_nr_migrate = 32;
849 * ratelimit for updating the group shares.
852 unsigned int sysctl_sched_shares_ratelimit = 250000;
855 * Inject some fuzzyness into changing the per-cpu group shares
856 * this avoids remote rq-locks at the expense of fairness.
859 unsigned int sysctl_sched_shares_thresh = 4;
862 * period over which we measure -rt task cpu usage in us.
865 unsigned int sysctl_sched_rt_period = 1000000;
867 static __read_mostly int scheduler_running;
870 * part of the period that we allow rt tasks to run in us.
873 int sysctl_sched_rt_runtime = 950000;
875 static inline u64 global_rt_period(void)
877 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
880 static inline u64 global_rt_runtime(void)
882 if (sysctl_sched_rt_runtime < 0)
885 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
888 #ifndef prepare_arch_switch
889 # define prepare_arch_switch(next) do { } while (0)
891 #ifndef finish_arch_switch
892 # define finish_arch_switch(prev) do { } while (0)
895 static inline int task_current(struct rq *rq, struct task_struct *p)
897 return rq->curr == p;
900 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
901 static inline int task_running(struct rq *rq, struct task_struct *p)
903 return task_current(rq, p);
906 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
910 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
912 #ifdef CONFIG_DEBUG_SPINLOCK
913 /* this is a valid case when another task releases the spinlock */
914 rq->lock.owner = current;
917 * If we are tracking spinlock dependencies then we have to
918 * fix up the runqueue lock - which gets 'carried over' from
921 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
923 spin_unlock_irq(&rq->lock);
926 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
927 static inline int task_running(struct rq *rq, struct task_struct *p)
932 return task_current(rq, p);
936 static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
940 * We can optimise this out completely for !SMP, because the
941 * SMP rebalancing from interrupt is the only thing that cares
946 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
947 spin_unlock_irq(&rq->lock);
949 spin_unlock(&rq->lock);
953 static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
957 * After ->oncpu is cleared, the task can be moved to a different CPU.
958 * We must ensure this doesn't happen until the switch is completely
964 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
968 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
971 * __task_rq_lock - lock the runqueue a given task resides on.
972 * Must be called interrupts disabled.
974 static inline struct rq *__task_rq_lock(struct task_struct *p)
978 struct rq *rq = task_rq(p);
979 spin_lock(&rq->lock);
980 if (likely(rq == task_rq(p)))
982 spin_unlock(&rq->lock);
987 * task_rq_lock - lock the runqueue a given task resides on and disable
988 * interrupts. Note the ordering: we can safely lookup the task_rq without
989 * explicitly disabling preemption.
991 static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
997 local_irq_save(*flags);
999 spin_lock(&rq->lock);
1000 if (likely(rq == task_rq(p)))
1002 spin_unlock_irqrestore(&rq->lock, *flags);
1006 void task_rq_unlock_wait(struct task_struct *p)
1008 struct rq *rq = task_rq(p);
1010 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
1011 spin_unlock_wait(&rq->lock);
1014 static void __task_rq_unlock(struct rq *rq)
1015 __releases(rq->lock)
1017 spin_unlock(&rq->lock);
1020 static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
1021 __releases(rq->lock)
1023 spin_unlock_irqrestore(&rq->lock, *flags);
1027 * this_rq_lock - lock this runqueue and disable interrupts.
1029 static struct rq *this_rq_lock(void)
1030 __acquires(rq->lock)
1034 local_irq_disable();
1036 spin_lock(&rq->lock);
1041 #ifdef CONFIG_SCHED_HRTICK
1043 * Use HR-timers to deliver accurate preemption points.
1045 * Its all a bit involved since we cannot program an hrt while holding the
1046 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1049 * When we get rescheduled we reprogram the hrtick_timer outside of the
1055 * - enabled by features
1056 * - hrtimer is actually high res
1058 static inline int hrtick_enabled(struct rq *rq)
1060 if (!sched_feat(HRTICK))
1062 if (!cpu_active(cpu_of(rq)))
1064 return hrtimer_is_hres_active(&rq->hrtick_timer);
1067 static void hrtick_clear(struct rq *rq)
1069 if (hrtimer_active(&rq->hrtick_timer))
1070 hrtimer_cancel(&rq->hrtick_timer);
1074 * High-resolution timer tick.
1075 * Runs from hardirq context with interrupts disabled.
1077 static enum hrtimer_restart hrtick(struct hrtimer *timer)
1079 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1081 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1083 spin_lock(&rq->lock);
1084 update_rq_clock(rq);
1085 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1086 spin_unlock(&rq->lock);
1088 return HRTIMER_NORESTART;
1093 * called from hardirq (IPI) context
1095 static void __hrtick_start(void *arg)
1097 struct rq *rq = arg;
1099 spin_lock(&rq->lock);
1100 hrtimer_restart(&rq->hrtick_timer);
1101 rq->hrtick_csd_pending = 0;
1102 spin_unlock(&rq->lock);
1106 * Called to set the hrtick timer state.
1108 * called with rq->lock held and irqs disabled
1110 static void hrtick_start(struct rq *rq, u64 delay)
1112 struct hrtimer *timer = &rq->hrtick_timer;
1113 ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
1115 hrtimer_set_expires(timer, time);
1117 if (rq == this_rq()) {
1118 hrtimer_restart(timer);
1119 } else if (!rq->hrtick_csd_pending) {
1120 __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
1121 rq->hrtick_csd_pending = 1;
1126 hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1128 int cpu = (int)(long)hcpu;
1131 case CPU_UP_CANCELED:
1132 case CPU_UP_CANCELED_FROZEN:
1133 case CPU_DOWN_PREPARE:
1134 case CPU_DOWN_PREPARE_FROZEN:
1136 case CPU_DEAD_FROZEN:
1137 hrtick_clear(cpu_rq(cpu));
1144 static __init void init_hrtick(void)
1146 hotcpu_notifier(hotplug_hrtick, 0);
1150 * Called to set the hrtick timer state.
1152 * called with rq->lock held and irqs disabled
1154 static void hrtick_start(struct rq *rq, u64 delay)
1156 __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
1157 HRTIMER_MODE_REL_PINNED, 0);
1160 static inline void init_hrtick(void)
1163 #endif /* CONFIG_SMP */
1165 static void init_rq_hrtick(struct rq *rq)
1168 rq->hrtick_csd_pending = 0;
1170 rq->hrtick_csd.flags = 0;
1171 rq->hrtick_csd.func = __hrtick_start;
1172 rq->hrtick_csd.info = rq;
1175 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1176 rq->hrtick_timer.function = hrtick;
1178 #else /* CONFIG_SCHED_HRTICK */
1179 static inline void hrtick_clear(struct rq *rq)
1183 static inline void init_rq_hrtick(struct rq *rq)
1187 static inline void init_hrtick(void)
1190 #endif /* CONFIG_SCHED_HRTICK */
1193 * resched_task - mark a task 'to be rescheduled now'.
1195 * On UP this means the setting of the need_resched flag, on SMP it
1196 * might also involve a cross-CPU call to trigger the scheduler on
1201 #ifndef tsk_is_polling
1202 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1205 static void resched_task(struct task_struct *p)
1209 assert_spin_locked(&task_rq(p)->lock);
1211 if (test_tsk_need_resched(p))
1214 set_tsk_need_resched(p);
1217 if (cpu == smp_processor_id())
1220 /* NEED_RESCHED must be visible before we test polling */
1222 if (!tsk_is_polling(p))
1223 smp_send_reschedule(cpu);
1226 static void resched_cpu(int cpu)
1228 struct rq *rq = cpu_rq(cpu);
1229 unsigned long flags;
1231 if (!spin_trylock_irqsave(&rq->lock, flags))
1233 resched_task(cpu_curr(cpu));
1234 spin_unlock_irqrestore(&rq->lock, flags);
1239 * When add_timer_on() enqueues a timer into the timer wheel of an
1240 * idle CPU then this timer might expire before the next timer event
1241 * which is scheduled to wake up that CPU. In case of a completely
1242 * idle system the next event might even be infinite time into the
1243 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1244 * leaves the inner idle loop so the newly added timer is taken into
1245 * account when the CPU goes back to idle and evaluates the timer
1246 * wheel for the next timer event.
1248 void wake_up_idle_cpu(int cpu)
1250 struct rq *rq = cpu_rq(cpu);
1252 if (cpu == smp_processor_id())
1256 * This is safe, as this function is called with the timer
1257 * wheel base lock of (cpu) held. When the CPU is on the way
1258 * to idle and has not yet set rq->curr to idle then it will
1259 * be serialized on the timer wheel base lock and take the new
1260 * timer into account automatically.
1262 if (rq->curr != rq->idle)
1266 * We can set TIF_RESCHED on the idle task of the other CPU
1267 * lockless. The worst case is that the other CPU runs the
1268 * idle task through an additional NOOP schedule()
1270 set_tsk_need_resched(rq->idle);
1272 /* NEED_RESCHED must be visible before we test polling */
1274 if (!tsk_is_polling(rq->idle))
1275 smp_send_reschedule(cpu);
1277 #endif /* CONFIG_NO_HZ */
1279 #else /* !CONFIG_SMP */
1280 static void resched_task(struct task_struct *p)
1282 assert_spin_locked(&task_rq(p)->lock);
1283 set_tsk_need_resched(p);
1285 #endif /* CONFIG_SMP */
1287 #if BITS_PER_LONG == 32
1288 # define WMULT_CONST (~0UL)
1290 # define WMULT_CONST (1UL << 32)
1293 #define WMULT_SHIFT 32
1296 * Shift right and round:
1298 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1301 * delta *= weight / lw
1303 static unsigned long
1304 calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1305 struct load_weight *lw)
1309 if (!lw->inv_weight) {
1310 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1313 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1317 tmp = (u64)delta_exec * weight;
1319 * Check whether we'd overflow the 64-bit multiplication:
1321 if (unlikely(tmp > WMULT_CONST))
1322 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
1325 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
1327 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
1330 static inline void update_load_add(struct load_weight *lw, unsigned long inc)
1336 static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
1343 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1344 * of tasks with abnormal "nice" values across CPUs the contribution that
1345 * each task makes to its run queue's load is weighted according to its
1346 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1347 * scaled version of the new time slice allocation that they receive on time
1351 #define WEIGHT_IDLEPRIO 3
1352 #define WMULT_IDLEPRIO 1431655765
1355 * Nice levels are multiplicative, with a gentle 10% change for every
1356 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1357 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1358 * that remained on nice 0.
1360 * The "10% effect" is relative and cumulative: from _any_ nice level,
1361 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1362 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1363 * If a task goes up by ~10% and another task goes down by ~10% then
1364 * the relative distance between them is ~25%.)
1366 static const int prio_to_weight[40] = {
1367 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1368 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1369 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1370 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1371 /* 0 */ 1024, 820, 655, 526, 423,
1372 /* 5 */ 335, 272, 215, 172, 137,
1373 /* 10 */ 110, 87, 70, 56, 45,
1374 /* 15 */ 36, 29, 23, 18, 15,
1378 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1380 * In cases where the weight does not change often, we can use the
1381 * precalculated inverse to speed up arithmetics by turning divisions
1382 * into multiplications:
1384 static const u32 prio_to_wmult[40] = {
1385 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1386 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1387 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1388 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1389 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1390 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1391 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1392 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1395 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
1398 * runqueue iterator, to support SMP load-balancing between different
1399 * scheduling classes, without having to expose their internal data
1400 * structures to the load-balancing proper:
1402 struct rq_iterator {
1404 struct task_struct *(*start)(void *);
1405 struct task_struct *(*next)(void *);
1409 static unsigned long
1410 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
1411 unsigned long max_load_move, struct sched_domain *sd,
1412 enum cpu_idle_type idle, int *all_pinned,
1413 int *this_best_prio, struct rq_iterator *iterator);
1416 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
1417 struct sched_domain *sd, enum cpu_idle_type idle,
1418 struct rq_iterator *iterator);
1421 /* Time spent by the tasks of the cpu accounting group executing in ... */
1422 enum cpuacct_stat_index {
1423 CPUACCT_STAT_USER, /* ... user mode */
1424 CPUACCT_STAT_SYSTEM, /* ... kernel mode */
1426 CPUACCT_STAT_NSTATS,
1429 #ifdef CONFIG_CGROUP_CPUACCT
1430 static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1431 static void cpuacct_update_stats(struct task_struct *tsk,
1432 enum cpuacct_stat_index idx, cputime_t val);
1434 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1435 static inline void cpuacct_update_stats(struct task_struct *tsk,
1436 enum cpuacct_stat_index idx, cputime_t val) {}
1439 static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1441 update_load_add(&rq->load, load);
1444 static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1446 update_load_sub(&rq->load, load);
1449 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1450 typedef int (*tg_visitor)(struct task_group *, void *);
1453 * Iterate the full tree, calling @down when first entering a node and @up when
1454 * leaving it for the final time.
1456 static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
1458 struct task_group *parent, *child;
1462 parent = &root_task_group;
1464 ret = (*down)(parent, data);
1467 list_for_each_entry_rcu(child, &parent->children, siblings) {
1474 ret = (*up)(parent, data);
1479 parent = parent->parent;
1488 static int tg_nop(struct task_group *tg, void *data)
1495 static unsigned long source_load(int cpu, int type);
1496 static unsigned long target_load(int cpu, int type);
1497 static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
1499 static unsigned long cpu_avg_load_per_task(int cpu)
1501 struct rq *rq = cpu_rq(cpu);
1502 unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
1505 rq->avg_load_per_task = rq->load.weight / nr_running;
1507 rq->avg_load_per_task = 0;
1509 return rq->avg_load_per_task;
1512 #ifdef CONFIG_FAIR_GROUP_SCHED
1514 static void __set_se_shares(struct sched_entity *se, unsigned long shares);
1517 * Calculate and set the cpu's group shares.
1520 update_group_shares_cpu(struct task_group *tg, int cpu,
1521 unsigned long sd_shares, unsigned long sd_rq_weight)
1523 unsigned long shares;
1524 unsigned long rq_weight;
1529 rq_weight = tg->cfs_rq[cpu]->rq_weight;
1532 * \Sum shares * rq_weight
1533 * shares = -----------------------
1537 shares = (sd_shares * rq_weight) / sd_rq_weight;
1538 shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
1540 if (abs(shares - tg->se[cpu]->load.weight) >
1541 sysctl_sched_shares_thresh) {
1542 struct rq *rq = cpu_rq(cpu);
1543 unsigned long flags;
1545 spin_lock_irqsave(&rq->lock, flags);
1546 tg->cfs_rq[cpu]->shares = shares;
1548 __set_se_shares(tg->se[cpu], shares);
1549 spin_unlock_irqrestore(&rq->lock, flags);
1554 * Re-compute the task group their per cpu shares over the given domain.
1555 * This needs to be done in a bottom-up fashion because the rq weight of a
1556 * parent group depends on the shares of its child groups.
1558 static int tg_shares_up(struct task_group *tg, void *data)
1560 unsigned long weight, rq_weight = 0;
1561 unsigned long shares = 0;
1562 struct sched_domain *sd = data;
1565 for_each_cpu(i, sched_domain_span(sd)) {
1567 * If there are currently no tasks on the cpu pretend there
1568 * is one of average load so that when a new task gets to
1569 * run here it will not get delayed by group starvation.
1571 weight = tg->cfs_rq[i]->load.weight;
1573 weight = NICE_0_LOAD;
1575 tg->cfs_rq[i]->rq_weight = weight;
1576 rq_weight += weight;
1577 shares += tg->cfs_rq[i]->shares;
1580 if ((!shares && rq_weight) || shares > tg->shares)
1581 shares = tg->shares;
1583 if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
1584 shares = tg->shares;
1586 for_each_cpu(i, sched_domain_span(sd))
1587 update_group_shares_cpu(tg, i, shares, rq_weight);
1593 * Compute the cpu's hierarchical load factor for each task group.
1594 * This needs to be done in a top-down fashion because the load of a child
1595 * group is a fraction of its parents load.
1597 static int tg_load_down(struct task_group *tg, void *data)
1600 long cpu = (long)data;
1603 load = cpu_rq(cpu)->load.weight;
1605 load = tg->parent->cfs_rq[cpu]->h_load;
1606 load *= tg->cfs_rq[cpu]->shares;
1607 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
1610 tg->cfs_rq[cpu]->h_load = load;
1615 static void update_shares(struct sched_domain *sd)
1617 u64 now = cpu_clock(raw_smp_processor_id());
1618 s64 elapsed = now - sd->last_update;
1620 if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
1621 sd->last_update = now;
1622 walk_tg_tree(tg_nop, tg_shares_up, sd);
1626 static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1628 spin_unlock(&rq->lock);
1630 spin_lock(&rq->lock);
1633 static void update_h_load(long cpu)
1635 walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
1640 static inline void update_shares(struct sched_domain *sd)
1644 static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
1650 #ifdef CONFIG_PREEMPT
1653 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1654 * way at the expense of forcing extra atomic operations in all
1655 * invocations. This assures that the double_lock is acquired using the
1656 * same underlying policy as the spinlock_t on this architecture, which
1657 * reduces latency compared to the unfair variant below. However, it
1658 * also adds more overhead and therefore may reduce throughput.
1660 static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1661 __releases(this_rq->lock)
1662 __acquires(busiest->lock)
1663 __acquires(this_rq->lock)
1665 spin_unlock(&this_rq->lock);
1666 double_rq_lock(this_rq, busiest);
1673 * Unfair double_lock_balance: Optimizes throughput at the expense of
1674 * latency by eliminating extra atomic operations when the locks are
1675 * already in proper order on entry. This favors lower cpu-ids and will
1676 * grant the double lock to lower cpus over higher ids under contention,
1677 * regardless of entry order into the function.
1679 static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
1680 __releases(this_rq->lock)
1681 __acquires(busiest->lock)
1682 __acquires(this_rq->lock)
1686 if (unlikely(!spin_trylock(&busiest->lock))) {
1687 if (busiest < this_rq) {
1688 spin_unlock(&this_rq->lock);
1689 spin_lock(&busiest->lock);
1690 spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING);
1693 spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING);
1698 #endif /* CONFIG_PREEMPT */
1701 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1703 static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
1705 if (unlikely(!irqs_disabled())) {
1706 /* printk() doesn't work good under rq->lock */
1707 spin_unlock(&this_rq->lock);
1711 return _double_lock_balance(this_rq, busiest);
1714 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
1715 __releases(busiest->lock)
1717 spin_unlock(&busiest->lock);
1718 lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
1722 #ifdef CONFIG_FAIR_GROUP_SCHED
1723 static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
1726 cfs_rq->shares = shares;
1731 #include "sched_stats.h"
1732 #include "sched_idletask.c"
1733 #include "sched_fair.c"
1734 #include "sched_rt.c"
1735 #ifdef CONFIG_SCHED_DEBUG
1736 # include "sched_debug.c"
1739 #define sched_class_highest (&rt_sched_class)
1740 #define for_each_class(class) \
1741 for (class = sched_class_highest; class; class = class->next)
1743 static void inc_nr_running(struct rq *rq)
1748 static void dec_nr_running(struct rq *rq)
1753 static void set_load_weight(struct task_struct *p)
1755 if (task_has_rt_policy(p)) {
1756 p->se.load.weight = prio_to_weight[0] * 2;
1757 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1762 * SCHED_IDLE tasks get minimal weight:
1764 if (p->policy == SCHED_IDLE) {
1765 p->se.load.weight = WEIGHT_IDLEPRIO;
1766 p->se.load.inv_weight = WMULT_IDLEPRIO;
1770 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1771 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
1774 static void update_avg(u64 *avg, u64 sample)
1776 s64 diff = sample - *avg;
1780 static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
1783 p->se.start_runtime = p->se.sum_exec_runtime;
1785 sched_info_queued(p);
1786 p->sched_class->enqueue_task(rq, p, wakeup);
1790 static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
1793 if (p->se.last_wakeup) {
1794 update_avg(&p->se.avg_overlap,
1795 p->se.sum_exec_runtime - p->se.last_wakeup);
1796 p->se.last_wakeup = 0;
1798 update_avg(&p->se.avg_wakeup,
1799 sysctl_sched_wakeup_granularity);
1803 sched_info_dequeued(p);
1804 p->sched_class->dequeue_task(rq, p, sleep);
1809 * __normal_prio - return the priority that is based on the static prio
1811 static inline int __normal_prio(struct task_struct *p)
1813 return p->static_prio;
1817 * Calculate the expected normal priority: i.e. priority
1818 * without taking RT-inheritance into account. Might be
1819 * boosted by interactivity modifiers. Changes upon fork,
1820 * setprio syscalls, and whenever the interactivity
1821 * estimator recalculates.
1823 static inline int normal_prio(struct task_struct *p)
1827 if (task_has_rt_policy(p))
1828 prio = MAX_RT_PRIO-1 - p->rt_priority;
1830 prio = __normal_prio(p);
1835 * Calculate the current priority, i.e. the priority
1836 * taken into account by the scheduler. This value might
1837 * be boosted by RT tasks, or might be boosted by
1838 * interactivity modifiers. Will be RT if the task got
1839 * RT-boosted. If not then it returns p->normal_prio.
1841 static int effective_prio(struct task_struct *p)
1843 p->normal_prio = normal_prio(p);
1845 * If we are RT tasks or we were boosted to RT priority,
1846 * keep the priority unchanged. Otherwise, update priority
1847 * to the normal priority:
1849 if (!rt_prio(p->prio))
1850 return p->normal_prio;
1855 * activate_task - move a task to the runqueue.
1857 static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
1859 if (task_contributes_to_load(p))
1860 rq->nr_uninterruptible--;
1862 enqueue_task(rq, p, wakeup);
1867 * deactivate_task - remove a task from the runqueue.
1869 static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
1871 if (task_contributes_to_load(p))
1872 rq->nr_uninterruptible++;
1874 dequeue_task(rq, p, sleep);
1879 * task_curr - is this task currently executing on a CPU?
1880 * @p: the task in question.
1882 inline int task_curr(const struct task_struct *p)
1884 return cpu_curr(task_cpu(p)) == p;
1887 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1889 set_task_rq(p, cpu);
1892 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1893 * successfuly executed on another CPU. We must ensure that updates of
1894 * per-task data have been completed by this moment.
1897 task_thread_info(p)->cpu = cpu;
1901 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1902 const struct sched_class *prev_class,
1903 int oldprio, int running)
1905 if (prev_class != p->sched_class) {
1906 if (prev_class->switched_from)
1907 prev_class->switched_from(rq, p, running);
1908 p->sched_class->switched_to(rq, p, running);
1910 p->sched_class->prio_changed(rq, p, oldprio, running);
1915 /* Used instead of source_load when we know the type == 0 */
1916 static unsigned long weighted_cpuload(const int cpu)
1918 return cpu_rq(cpu)->load.weight;
1922 * Is this task likely cache-hot:
1925 task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1930 * Buddy candidates are cache hot:
1932 if (sched_feat(CACHE_HOT_BUDDY) &&
1933 (&p->se == cfs_rq_of(&p->se)->next ||
1934 &p->se == cfs_rq_of(&p->se)->last))
1937 if (p->sched_class != &fair_sched_class)
1940 if (sysctl_sched_migration_cost == -1)
1942 if (sysctl_sched_migration_cost == 0)
1945 delta = now - p->se.exec_start;
1947 return delta < (s64)sysctl_sched_migration_cost;
1951 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
1953 int old_cpu = task_cpu(p);
1954 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
1955 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1956 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
1959 clock_offset = old_rq->clock - new_rq->clock;
1961 trace_sched_migrate_task(p, task_cpu(p), new_cpu);
1963 #ifdef CONFIG_SCHEDSTATS
1964 if (p->se.wait_start)
1965 p->se.wait_start -= clock_offset;
1966 if (p->se.sleep_start)
1967 p->se.sleep_start -= clock_offset;
1968 if (p->se.block_start)
1969 p->se.block_start -= clock_offset;
1970 if (old_cpu != new_cpu) {
1971 schedstat_inc(p, se.nr_migrations);
1972 if (task_hot(p, old_rq->clock, NULL))
1973 schedstat_inc(p, se.nr_forced2_migrations);
1976 p->se.vruntime -= old_cfsrq->min_vruntime -
1977 new_cfsrq->min_vruntime;
1979 __set_task_cpu(p, new_cpu);
1982 struct migration_req {
1983 struct list_head list;
1985 struct task_struct *task;
1988 struct completion done;
1992 * The task's runqueue lock must be held.
1993 * Returns true if you have to wait for migration thread.
1996 migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
1998 struct rq *rq = task_rq(p);
2001 * If the task is not on a runqueue (and not running), then
2002 * it is sufficient to simply update the task's cpu field.
2004 if (!p->se.on_rq && !task_running(rq, p)) {
2005 set_task_cpu(p, dest_cpu);
2009 init_completion(&req->done);
2011 req->dest_cpu = dest_cpu;
2012 list_add(&req->list, &rq->migration_queue);
2018 * wait_task_inactive - wait for a thread to unschedule.
2020 * If @match_state is nonzero, it's the @p->state value just checked and
2021 * not expected to change. If it changes, i.e. @p might have woken up,
2022 * then return zero. When we succeed in waiting for @p to be off its CPU,
2023 * we return a positive number (its total switch count). If a second call
2024 * a short while later returns the same number, the caller can be sure that
2025 * @p has remained unscheduled the whole time.
2027 * The caller must ensure that the task *will* unschedule sometime soon,
2028 * else this function might spin for a *long* time. This function can't
2029 * be called with interrupts off, or it may introduce deadlock with
2030 * smp_call_function() if an IPI is sent by the same process we are
2031 * waiting to become inactive.
2033 unsigned long wait_task_inactive(struct task_struct *p, long match_state)
2035 unsigned long flags;
2042 * We do the initial early heuristics without holding
2043 * any task-queue locks at all. We'll only try to get
2044 * the runqueue lock when things look like they will
2050 * If the task is actively running on another CPU
2051 * still, just relax and busy-wait without holding
2054 * NOTE! Since we don't hold any locks, it's not
2055 * even sure that "rq" stays as the right runqueue!
2056 * But we don't care, since "task_running()" will
2057 * return false if the runqueue has changed and p
2058 * is actually now running somewhere else!
2060 while (task_running(rq, p)) {
2061 if (match_state && unlikely(p->state != match_state))
2067 * Ok, time to look more closely! We need the rq
2068 * lock now, to be *sure*. If we're wrong, we'll
2069 * just go back and repeat.
2071 rq = task_rq_lock(p, &flags);
2072 trace_sched_wait_task(rq, p);
2073 running = task_running(rq, p);
2074 on_rq = p->se.on_rq;
2076 if (!match_state || p->state == match_state)
2077 ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
2078 task_rq_unlock(rq, &flags);
2081 * If it changed from the expected state, bail out now.
2083 if (unlikely(!ncsw))
2087 * Was it really running after all now that we
2088 * checked with the proper locks actually held?
2090 * Oops. Go back and try again..
2092 if (unlikely(running)) {
2098 * It's not enough that it's not actively running,
2099 * it must be off the runqueue _entirely_, and not
2102 * So if it was still runnable (but just not actively
2103 * running right now), it's preempted, and we should
2104 * yield - it could be a while.
2106 if (unlikely(on_rq)) {
2107 schedule_timeout_uninterruptible(1);
2112 * Ahh, all good. It wasn't running, and it wasn't
2113 * runnable, which means that it will never become
2114 * running in the future either. We're all done!
2123 * kick_process - kick a running thread to enter/exit the kernel
2124 * @p: the to-be-kicked thread
2126 * Cause a process which is running on another CPU to enter
2127 * kernel-mode, without any delay. (to get signals handled.)
2129 * NOTE: this function doesnt have to take the runqueue lock,
2130 * because all it wants to ensure is that the remote task enters
2131 * the kernel. If the IPI races and the task has been migrated
2132 * to another CPU then no harm is done and the purpose has been
2135 void kick_process(struct task_struct *p)
2141 if ((cpu != smp_processor_id()) && task_curr(p))
2142 smp_send_reschedule(cpu);
2147 * Return a low guess at the load of a migration-source cpu weighted
2148 * according to the scheduling class and "nice" value.
2150 * We want to under-estimate the load of migration sources, to
2151 * balance conservatively.
2153 static unsigned long source_load(int cpu, int type)
2155 struct rq *rq = cpu_rq(cpu);
2156 unsigned long total = weighted_cpuload(cpu);
2158 if (type == 0 || !sched_feat(LB_BIAS))
2161 return min(rq->cpu_load[type-1], total);
2165 * Return a high guess at the load of a migration-target cpu weighted
2166 * according to the scheduling class and "nice" value.
2168 static unsigned long target_load(int cpu, int type)
2170 struct rq *rq = cpu_rq(cpu);
2171 unsigned long total = weighted_cpuload(cpu);
2173 if (type == 0 || !sched_feat(LB_BIAS))
2176 return max(rq->cpu_load[type-1], total);
2180 * find_idlest_group finds and returns the least busy CPU group within the
2183 static struct sched_group *
2184 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
2186 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
2187 unsigned long min_load = ULONG_MAX, this_load = 0;
2188 int load_idx = sd->forkexec_idx;
2189 int imbalance = 100 + (sd->imbalance_pct-100)/2;
2192 unsigned long load, avg_load;
2196 /* Skip over this group if it has no CPUs allowed */
2197 if (!cpumask_intersects(sched_group_cpus(group),
2201 local_group = cpumask_test_cpu(this_cpu,
2202 sched_group_cpus(group));
2204 /* Tally up the load of all CPUs in the group */
2207 for_each_cpu(i, sched_group_cpus(group)) {
2208 /* Bias balancing toward cpus of our domain */
2210 load = source_load(i, load_idx);
2212 load = target_load(i, load_idx);
2217 /* Adjust by relative CPU power of the group */
2218 avg_load = sg_div_cpu_power(group,
2219 avg_load * SCHED_LOAD_SCALE);
2222 this_load = avg_load;
2224 } else if (avg_load < min_load) {
2225 min_load = avg_load;
2228 } while (group = group->next, group != sd->groups);
2230 if (!idlest || 100*this_load < imbalance*min_load)
2236 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2239 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
2241 unsigned long load, min_load = ULONG_MAX;
2245 /* Traverse only the allowed CPUs */
2246 for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {
2247 load = weighted_cpuload(i);
2249 if (load < min_load || (load == min_load && i == this_cpu)) {
2259 * sched_balance_self: balance the current task (running on cpu) in domains
2260 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2263 * Balance, ie. select the least loaded group.
2265 * Returns the target CPU number, or the same CPU if no balancing is needed.
2267 * preempt must be disabled.
2269 static int sched_balance_self(int cpu, int flag)
2271 struct task_struct *t = current;
2272 struct sched_domain *tmp, *sd = NULL;
2274 for_each_domain(cpu, tmp) {
2276 * If power savings logic is enabled for a domain, stop there.
2278 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2280 if (tmp->flags & flag)
2288 struct sched_group *group;
2289 int new_cpu, weight;
2291 if (!(sd->flags & flag)) {
2296 group = find_idlest_group(sd, t, cpu);
2302 new_cpu = find_idlest_cpu(group, t, cpu);
2303 if (new_cpu == -1 || new_cpu == cpu) {
2304 /* Now try balancing at a lower domain level of cpu */
2309 /* Now try balancing at a lower domain level of new_cpu */
2311 weight = cpumask_weight(sched_domain_span(sd));
2313 for_each_domain(cpu, tmp) {
2314 if (weight <= cpumask_weight(sched_domain_span(tmp)))
2316 if (tmp->flags & flag)
2319 /* while loop will break here if sd == NULL */
2325 #endif /* CONFIG_SMP */
2328 * try_to_wake_up - wake up a thread
2329 * @p: the to-be-woken-up thread
2330 * @state: the mask of task states that can be woken
2331 * @sync: do a synchronous wakeup?
2333 * Put it on the run-queue if it's not already there. The "current"
2334 * thread is always on the run-queue (except when the actual
2335 * re-schedule is in progress), and as such you're allowed to do
2336 * the simpler "current->state = TASK_RUNNING" to mark yourself
2337 * runnable without the overhead of this.
2339 * returns failure only if the task is already active.
2341 static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
2343 int cpu, orig_cpu, this_cpu, success = 0;
2344 unsigned long flags;
2348 if (!sched_feat(SYNC_WAKEUPS))
2352 if (sched_feat(LB_WAKEUP_UPDATE) && !root_task_group_empty()) {
2353 struct sched_domain *sd;
2355 this_cpu = raw_smp_processor_id();
2358 for_each_domain(this_cpu, sd) {
2359 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2368 rq = task_rq_lock(p, &flags);
2369 update_rq_clock(rq);
2370 old_state = p->state;
2371 if (!(old_state & state))
2379 this_cpu = smp_processor_id();
2382 if (unlikely(task_running(rq, p)))
2385 cpu = p->sched_class->select_task_rq(p, sync);
2386 if (cpu != orig_cpu) {
2387 set_task_cpu(p, cpu);
2388 task_rq_unlock(rq, &flags);
2389 /* might preempt at this point */
2390 rq = task_rq_lock(p, &flags);
2391 old_state = p->state;
2392 if (!(old_state & state))
2397 this_cpu = smp_processor_id();
2401 #ifdef CONFIG_SCHEDSTATS
2402 schedstat_inc(rq, ttwu_count);
2403 if (cpu == this_cpu)
2404 schedstat_inc(rq, ttwu_local);
2406 struct sched_domain *sd;
2407 for_each_domain(this_cpu, sd) {
2408 if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
2409 schedstat_inc(sd, ttwu_wake_remote);
2414 #endif /* CONFIG_SCHEDSTATS */
2417 #endif /* CONFIG_SMP */
2418 schedstat_inc(p, se.nr_wakeups);
2420 schedstat_inc(p, se.nr_wakeups_sync);
2421 if (orig_cpu != cpu)
2422 schedstat_inc(p, se.nr_wakeups_migrate);
2423 if (cpu == this_cpu)
2424 schedstat_inc(p, se.nr_wakeups_local);
2426 schedstat_inc(p, se.nr_wakeups_remote);
2427 activate_task(rq, p, 1);
2431 * Only attribute actual wakeups done by this task.
2433 if (!in_interrupt()) {
2434 struct sched_entity *se = ¤t->se;
2435 u64 sample = se->sum_exec_runtime;
2437 if (se->last_wakeup)
2438 sample -= se->last_wakeup;
2440 sample -= se->start_runtime;
2441 update_avg(&se->avg_wakeup, sample);
2443 se->last_wakeup = se->sum_exec_runtime;
2447 trace_sched_wakeup(rq, p, success);
2448 check_preempt_curr(rq, p, sync);
2450 p->state = TASK_RUNNING;
2452 if (p->sched_class->task_wake_up)
2453 p->sched_class->task_wake_up(rq, p);
2456 task_rq_unlock(rq, &flags);
2461 int wake_up_process(struct task_struct *p)
2463 return try_to_wake_up(p, TASK_ALL, 0);
2465 EXPORT_SYMBOL(wake_up_process);
2467 int wake_up_state(struct task_struct *p, unsigned int state)
2469 return try_to_wake_up(p, state, 0);
2473 * Perform scheduler related setup for a newly forked process p.
2474 * p is forked by current.
2476 * __sched_fork() is basic setup used by init_idle() too:
2478 static void __sched_fork(struct task_struct *p)
2480 p->se.exec_start = 0;
2481 p->se.sum_exec_runtime = 0;
2482 p->se.prev_sum_exec_runtime = 0;
2483 p->se.last_wakeup = 0;
2484 p->se.avg_overlap = 0;
2485 p->se.start_runtime = 0;
2486 p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
2488 #ifdef CONFIG_SCHEDSTATS
2489 p->se.wait_start = 0;
2490 p->se.sum_sleep_runtime = 0;
2491 p->se.sleep_start = 0;
2492 p->se.block_start = 0;
2493 p->se.sleep_max = 0;
2494 p->se.block_max = 0;
2496 p->se.slice_max = 0;
2500 INIT_LIST_HEAD(&p->rt.run_list);
2502 INIT_LIST_HEAD(&p->se.group_node);
2504 #ifdef CONFIG_PREEMPT_NOTIFIERS
2505 INIT_HLIST_HEAD(&p->preempt_notifiers);
2509 * We mark the process as running here, but have not actually
2510 * inserted it onto the runqueue yet. This guarantees that
2511 * nobody will actually run it, and a signal or other external
2512 * event cannot wake it up and insert it on the runqueue either.
2514 p->state = TASK_RUNNING;
2518 * fork()/clone()-time setup:
2520 void sched_fork(struct task_struct *p, int clone_flags)
2522 int cpu = get_cpu();
2527 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
2529 set_task_cpu(p, cpu);
2532 * Make sure we do not leak PI boosting priority to the child:
2534 p->prio = current->normal_prio;
2535 if (!rt_prio(p->prio))
2536 p->sched_class = &fair_sched_class;
2538 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2539 if (likely(sched_info_on()))
2540 memset(&p->sched_info, 0, sizeof(p->sched_info));
2542 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2545 #ifdef CONFIG_PREEMPT
2546 /* Want to start with kernel preemption disabled. */
2547 task_thread_info(p)->preempt_count = 1;
2549 plist_node_init(&p->pushable_tasks, MAX_PRIO);
2555 * wake_up_new_task - wake up a newly created task for the first time.
2557 * This function will do some initial scheduler statistics housekeeping
2558 * that must be done for every newly created context, then puts the task
2559 * on the runqueue and wakes it.
2561 void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
2563 unsigned long flags;
2566 rq = task_rq_lock(p, &flags);
2567 BUG_ON(p->state != TASK_RUNNING);
2568 update_rq_clock(rq);
2570 p->prio = effective_prio(p);
2572 if (!p->sched_class->task_new || !current->se.on_rq) {
2573 activate_task(rq, p, 0);
2576 * Let the scheduling class do new task startup
2577 * management (if any):
2579 p->sched_class->task_new(rq, p);
2582 trace_sched_wakeup_new(rq, p, 1);
2583 check_preempt_curr(rq, p, 0);
2585 if (p->sched_class->task_wake_up)
2586 p->sched_class->task_wake_up(rq, p);
2588 task_rq_unlock(rq, &flags);
2591 #ifdef CONFIG_PREEMPT_NOTIFIERS
2594 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2595 * @notifier: notifier struct to register
2597 void preempt_notifier_register(struct preempt_notifier *notifier)
2599 hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
2601 EXPORT_SYMBOL_GPL(preempt_notifier_register);
2604 * preempt_notifier_unregister - no longer interested in preemption notifications
2605 * @notifier: notifier struct to unregister
2607 * This is safe to call from within a preemption notifier.
2609 void preempt_notifier_unregister(struct preempt_notifier *notifier)
2611 hlist_del(¬ifier->link);
2613 EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2615 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2617 struct preempt_notifier *notifier;
2618 struct hlist_node *node;
2620 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2621 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2625 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2626 struct task_struct *next)
2628 struct preempt_notifier *notifier;
2629 struct hlist_node *node;
2631 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2632 notifier->ops->sched_out(notifier, next);
2635 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2637 static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2642 fire_sched_out_preempt_notifiers(struct task_struct *curr,
2643 struct task_struct *next)
2647 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2650 * prepare_task_switch - prepare to switch tasks
2651 * @rq: the runqueue preparing to switch
2652 * @prev: the current task that is being switched out
2653 * @next: the task we are going to switch to.
2655 * This is called with the rq lock held and interrupts off. It must
2656 * be paired with a subsequent finish_task_switch after the context
2659 * prepare_task_switch sets up locking and calls architecture specific
2663 prepare_task_switch(struct rq *rq, struct task_struct *prev,
2664 struct task_struct *next)
2666 fire_sched_out_preempt_notifiers(prev, next);
2667 prepare_lock_switch(rq, next);
2668 prepare_arch_switch(next);
2672 * finish_task_switch - clean up after a task-switch
2673 * @rq: runqueue associated with task-switch
2674 * @prev: the thread we just switched away from.
2676 * finish_task_switch must be called after the context switch, paired
2677 * with a prepare_task_switch call before the context switch.
2678 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2679 * and do any other architecture-specific cleanup actions.
2681 * Note that we may have delayed dropping an mm in context_switch(). If
2682 * so, we finish that here outside of the runqueue lock. (Doing it
2683 * with the lock held can cause deadlocks; see schedule() for
2686 static void finish_task_switch(struct rq *rq, struct task_struct *prev)
2687 __releases(rq->lock)
2689 struct mm_struct *mm = rq->prev_mm;
2692 int post_schedule = 0;
2694 if (current->sched_class->needs_post_schedule)
2695 post_schedule = current->sched_class->needs_post_schedule(rq);
2701 * A task struct has one reference for the use as "current".
2702 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2703 * schedule one last time. The schedule call will never return, and
2704 * the scheduled task must drop that reference.
2705 * The test for TASK_DEAD must occur while the runqueue locks are
2706 * still held, otherwise prev could be scheduled on another cpu, die
2707 * there before we look at prev->state, and then the reference would
2709 * Manfred Spraul <manfred@colorfullife.com>
2711 prev_state = prev->state;
2712 finish_arch_switch(prev);
2713 finish_lock_switch(rq, prev);
2716 current->sched_class->post_schedule(rq);
2719 fire_sched_in_preempt_notifiers(current);
2722 if (unlikely(prev_state == TASK_DEAD)) {
2724 * Remove function-return probe instances associated with this
2725 * task and put them back on the free list.
2727 kprobe_flush_task(prev);
2728 put_task_struct(prev);
2733 * schedule_tail - first thing a freshly forked thread must call.
2734 * @prev: the thread we just switched away from.
2736 asmlinkage void schedule_tail(struct task_struct *prev)
2737 __releases(rq->lock)
2739 struct rq *rq = this_rq();
2741 finish_task_switch(rq, prev);
2742 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2743 /* In this case, finish_task_switch does not reenable preemption */
2746 if (current->set_child_tid)
2747 put_user(task_pid_vnr(current), current->set_child_tid);
2751 * context_switch - switch to the new MM and the new
2752 * thread's register state.
2755 context_switch(struct rq *rq, struct task_struct *prev,
2756 struct task_struct *next)
2758 struct mm_struct *mm, *oldmm;
2760 prepare_task_switch(rq, prev, next);
2761 trace_sched_switch(rq, prev, next);
2763 oldmm = prev->active_mm;
2765 * For paravirt, this is coupled with an exit in switch_to to
2766 * combine the page table reload and the switch backend into
2769 arch_enter_lazy_cpu_mode();
2771 if (unlikely(!mm)) {
2772 next->active_mm = oldmm;
2773 atomic_inc(&oldmm->mm_count);
2774 enter_lazy_tlb(oldmm, next);
2776 switch_mm(oldmm, mm, next);
2778 if (unlikely(!prev->mm)) {
2779 prev->active_mm = NULL;
2780 rq->prev_mm = oldmm;
2783 * Since the runqueue lock will be released by the next
2784 * task (which is an invalid locking op but in the case
2785 * of the scheduler it's an obvious special-case), so we
2786 * do an early lockdep release here:
2788 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2789 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
2792 /* Here we just switch the register state and the stack. */
2793 switch_to(prev, next, prev);
2797 * this_rq must be evaluated again because prev may have moved
2798 * CPUs since it called schedule(), thus the 'rq' on its stack
2799 * frame will be invalid.
2801 finish_task_switch(this_rq(), prev);
2805 * nr_running, nr_uninterruptible and nr_context_switches:
2807 * externally visible scheduler statistics: current number of runnable
2808 * threads, current number of uninterruptible-sleeping threads, total
2809 * number of context switches performed since bootup.
2811 unsigned long nr_running(void)
2813 unsigned long i, sum = 0;
2815 for_each_online_cpu(i)
2816 sum += cpu_rq(i)->nr_running;
2821 unsigned long nr_uninterruptible(void)
2823 unsigned long i, sum = 0;
2825 for_each_possible_cpu(i)
2826 sum += cpu_rq(i)->nr_uninterruptible;
2829 * Since we read the counters lockless, it might be slightly
2830 * inaccurate. Do not allow it to go below zero though:
2832 if (unlikely((long)sum < 0))
2838 unsigned long long nr_context_switches(void)
2841 unsigned long long sum = 0;
2843 for_each_possible_cpu(i)
2844 sum += cpu_rq(i)->nr_switches;
2849 unsigned long nr_iowait(void)
2851 unsigned long i, sum = 0;
2853 for_each_possible_cpu(i)
2854 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2859 unsigned long nr_active(void)
2861 unsigned long i, running = 0, uninterruptible = 0;
2863 for_each_online_cpu(i) {
2864 running += cpu_rq(i)->nr_running;
2865 uninterruptible += cpu_rq(i)->nr_uninterruptible;
2868 if (unlikely((long)uninterruptible < 0))
2869 uninterruptible = 0;
2871 return running + uninterruptible;
2875 * Update rq->cpu_load[] statistics. This function is usually called every
2876 * scheduler tick (TICK_NSEC).
2878 static void update_cpu_load(struct rq *this_rq)
2880 unsigned long this_load = this_rq->load.weight;
2883 this_rq->nr_load_updates++;
2885 /* Update our load: */
2886 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2887 unsigned long old_load, new_load;
2889 /* scale is effectively 1 << i now, and >> i divides by scale */
2891 old_load = this_rq->cpu_load[i];
2892 new_load = this_load;
2894 * Round up the averaging division if load is increasing. This
2895 * prevents us from getting stuck on 9 if the load is 10, for
2898 if (new_load > old_load)
2899 new_load += scale-1;
2900 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
2907 * double_rq_lock - safely lock two runqueues
2909 * Note this does not disable interrupts like task_rq_lock,
2910 * you need to do so manually before calling.
2912 static void double_rq_lock(struct rq *rq1, struct rq *rq2)
2913 __acquires(rq1->lock)
2914 __acquires(rq2->lock)
2916 BUG_ON(!irqs_disabled());
2918 spin_lock(&rq1->lock);
2919 __acquire(rq2->lock); /* Fake it out ;) */
2922 spin_lock(&rq1->lock);
2923 spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
2925 spin_lock(&rq2->lock);
2926 spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
2929 update_rq_clock(rq1);
2930 update_rq_clock(rq2);
2934 * double_rq_unlock - safely unlock two runqueues
2936 * Note this does not restore interrupts like task_rq_unlock,
2937 * you need to do so manually after calling.
2939 static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
2940 __releases(rq1->lock)
2941 __releases(rq2->lock)
2943 spin_unlock(&rq1->lock);
2945 spin_unlock(&rq2->lock);
2947 __release(rq2->lock);
2951 * If dest_cpu is allowed for this process, migrate the task to it.
2952 * This is accomplished by forcing the cpu_allowed mask to only
2953 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2954 * the cpu_allowed mask is restored.
2956 static void sched_migrate_task(struct task_struct *p, int dest_cpu)
2958 struct migration_req req;
2959 unsigned long flags;
2962 rq = task_rq_lock(p, &flags);
2963 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed)
2964 || unlikely(!cpu_active(dest_cpu)))
2967 /* force the process onto the specified CPU */
2968 if (migrate_task(p, dest_cpu, &req)) {
2969 /* Need to wait for migration thread (might exit: take ref). */
2970 struct task_struct *mt = rq->migration_thread;
2972 get_task_struct(mt);
2973 task_rq_unlock(rq, &flags);
2974 wake_up_process(mt);
2975 put_task_struct(mt);
2976 wait_for_completion(&req.done);
2981 task_rq_unlock(rq, &flags);
2985 * sched_exec - execve() is a valuable balancing opportunity, because at
2986 * this point the task has the smallest effective memory and cache footprint.
2988 void sched_exec(void)
2990 int new_cpu, this_cpu = get_cpu();
2991 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
2993 if (new_cpu != this_cpu)
2994 sched_migrate_task(current, new_cpu);
2998 * pull_task - move a task from a remote runqueue to the local runqueue.
2999 * Both runqueues must be locked.
3001 static void pull_task(struct rq *src_rq, struct task_struct *p,
3002 struct rq *this_rq, int this_cpu)
3004 deactivate_task(src_rq, p, 0);
3005 set_task_cpu(p, this_cpu);
3006 activate_task(this_rq, p, 0);
3008 * Note that idle threads have a prio of MAX_PRIO, for this test
3009 * to be always true for them.
3011 check_preempt_curr(this_rq, p, 0);
3015 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3018 int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
3019 struct sched_domain *sd, enum cpu_idle_type idle,
3022 int tsk_cache_hot = 0;
3024 * We do not migrate tasks that are:
3025 * 1) running (obviously), or
3026 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3027 * 3) are cache-hot on their current CPU.
3029 if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) {
3030 schedstat_inc(p, se.nr_failed_migrations_affine);
3035 if (task_running(rq, p)) {
3036 schedstat_inc(p, se.nr_failed_migrations_running);
3041 * Aggressive migration if:
3042 * 1) task is cache cold, or
3043 * 2) too many balance attempts have failed.
3046 tsk_cache_hot = task_hot(p, rq->clock, sd);
3047 if (!tsk_cache_hot ||
3048 sd->nr_balance_failed > sd->cache_nice_tries) {
3049 #ifdef CONFIG_SCHEDSTATS
3050 if (tsk_cache_hot) {
3051 schedstat_inc(sd, lb_hot_gained[idle]);
3052 schedstat_inc(p, se.nr_forced_migrations);
3058 if (tsk_cache_hot) {
3059 schedstat_inc(p, se.nr_failed_migrations_hot);
3065 static unsigned long
3066 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3067 unsigned long max_load_move, struct sched_domain *sd,
3068 enum cpu_idle_type idle, int *all_pinned,
3069 int *this_best_prio, struct rq_iterator *iterator)
3071 int loops = 0, pulled = 0, pinned = 0;
3072 struct task_struct *p;
3073 long rem_load_move = max_load_move;
3075 if (max_load_move == 0)
3081 * Start the load-balancing iterator:
3083 p = iterator->start(iterator->arg);
3085 if (!p || loops++ > sysctl_sched_nr_migrate)
3088 if ((p->se.load.weight >> 1) > rem_load_move ||
3089 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3090 p = iterator->next(iterator->arg);
3094 pull_task(busiest, p, this_rq, this_cpu);
3096 rem_load_move -= p->se.load.weight;
3098 #ifdef CONFIG_PREEMPT
3100 * NEWIDLE balancing is a source of latency, so preemptible kernels
3101 * will stop after the first task is pulled to minimize the critical
3104 if (idle == CPU_NEWLY_IDLE)
3109 * We only want to steal up to the prescribed amount of weighted load.
3111 if (rem_load_move > 0) {
3112 if (p->prio < *this_best_prio)
3113 *this_best_prio = p->prio;
3114 p = iterator->next(iterator->arg);
3119 * Right now, this is one of only two places pull_task() is called,
3120 * so we can safely collect pull_task() stats here rather than
3121 * inside pull_task().
3123 schedstat_add(sd, lb_gained[idle], pulled);
3126 *all_pinned = pinned;
3128 return max_load_move - rem_load_move;
3132 * move_tasks tries to move up to max_load_move weighted load from busiest to
3133 * this_rq, as part of a balancing operation within domain "sd".
3134 * Returns 1 if successful and 0 otherwise.
3136 * Called with both runqueues locked.
3138 static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3139 unsigned long max_load_move,
3140 struct sched_domain *sd, enum cpu_idle_type idle,
3143 const struct sched_class *class = sched_class_highest;
3144 unsigned long total_load_moved = 0;
3145 int this_best_prio = this_rq->curr->prio;
3149 class->load_balance(this_rq, this_cpu, busiest,
3150 max_load_move - total_load_moved,
3151 sd, idle, all_pinned, &this_best_prio);
3152 class = class->next;
3154 #ifdef CONFIG_PREEMPT
3156 * NEWIDLE balancing is a source of latency, so preemptible
3157 * kernels will stop after the first task is pulled to minimize
3158 * the critical section.
3160 if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
3163 } while (class && max_load_move > total_load_moved);
3165 return total_load_moved > 0;
3169 iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3170 struct sched_domain *sd, enum cpu_idle_type idle,
3171 struct rq_iterator *iterator)
3173 struct task_struct *p = iterator->start(iterator->arg);
3177 if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
3178 pull_task(busiest, p, this_rq, this_cpu);
3180 * Right now, this is only the second place pull_task()
3181 * is called, so we can safely collect pull_task()
3182 * stats here rather than inside pull_task().
3184 schedstat_inc(sd, lb_gained[idle]);
3188 p = iterator->next(iterator->arg);
3195 * move_one_task tries to move exactly one task from busiest to this_rq, as
3196 * part of active balancing operations within "domain".
3197 * Returns 1 if successful and 0 otherwise.
3199 * Called with both runqueues locked.
3201 static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
3202 struct sched_domain *sd, enum cpu_idle_type idle)
3204 const struct sched_class *class;
3206 for (class = sched_class_highest; class; class = class->next)
3207 if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
3212 /********** Helpers for find_busiest_group ************************/
3214 * sd_lb_stats - Structure to store the statistics of a sched_domain
3215 * during load balancing.
3217 struct sd_lb_stats {
3218 struct sched_group *busiest; /* Busiest group in this sd */
3219 struct sched_group *this; /* Local group in this sd */
3220 unsigned long total_load; /* Total load of all groups in sd */
3221 unsigned long total_pwr; /* Total power of all groups in sd */
3222 unsigned long avg_load; /* Average load across all groups in sd */
3224 /** Statistics of this group */
3225 unsigned long this_load;
3226 unsigned long this_load_per_task;
3227 unsigned long this_nr_running;
3229 /* Statistics of the busiest group */
3230 unsigned long max_load;
3231 unsigned long busiest_load_per_task;
3232 unsigned long busiest_nr_running;
3234 int group_imb; /* Is there imbalance in this sd */
3235 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3236 int power_savings_balance; /* Is powersave balance needed for this sd */
3237 struct sched_group *group_min; /* Least loaded group in sd */
3238 struct sched_group *group_leader; /* Group which relieves group_min */
3239 unsigned long min_load_per_task; /* load_per_task in group_min */
3240 unsigned long leader_nr_running; /* Nr running of group_leader */
3241 unsigned long min_nr_running; /* Nr running of group_min */
3246 * sg_lb_stats - stats of a sched_group required for load_balancing
3248 struct sg_lb_stats {
3249 unsigned long avg_load; /*Avg load across the CPUs of the group */
3250 unsigned long group_load; /* Total load over the CPUs of the group */
3251 unsigned long sum_nr_running; /* Nr tasks running in the group */
3252 unsigned long sum_weighted_load; /* Weighted load of group's tasks */
3253 unsigned long group_capacity;
3254 int group_imb; /* Is there an imbalance in the group ? */
3258 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
3259 * @group: The group whose first cpu is to be returned.
3261 static inline unsigned int group_first_cpu(struct sched_group *group)
3263 return cpumask_first(sched_group_cpus(group));
3267 * get_sd_load_idx - Obtain the load index for a given sched domain.
3268 * @sd: The sched_domain whose load_idx is to be obtained.
3269 * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
3271 static inline int get_sd_load_idx(struct sched_domain *sd,
3272 enum cpu_idle_type idle)
3278 load_idx = sd->busy_idx;
3281 case CPU_NEWLY_IDLE:
3282 load_idx = sd->newidle_idx;
3285 load_idx = sd->idle_idx;
3293 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3295 * init_sd_power_savings_stats - Initialize power savings statistics for
3296 * the given sched_domain, during load balancing.
3298 * @sd: Sched domain whose power-savings statistics are to be initialized.
3299 * @sds: Variable containing the statistics for sd.
3300 * @idle: Idle status of the CPU at which we're performing load-balancing.
3302 static inline void init_sd_power_savings_stats(struct sched_domain *sd,
3303 struct sd_lb_stats *sds, enum cpu_idle_type idle)
3306 * Busy processors will not participate in power savings
3309 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
3310 sds->power_savings_balance = 0;
3312 sds->power_savings_balance = 1;
3313 sds->min_nr_running = ULONG_MAX;
3314 sds->leader_nr_running = 0;
3319 * update_sd_power_savings_stats - Update the power saving stats for a
3320 * sched_domain while performing load balancing.
3322 * @group: sched_group belonging to the sched_domain under consideration.
3323 * @sds: Variable containing the statistics of the sched_domain
3324 * @local_group: Does group contain the CPU for which we're performing
3326 * @sgs: Variable containing the statistics of the group.
3328 static inline void update_sd_power_savings_stats(struct sched_group *group,
3329 struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
3332 if (!sds->power_savings_balance)
3336 * If the local group is idle or completely loaded
3337 * no need to do power savings balance at this domain
3339 if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
3340 !sds->this_nr_running))
3341 sds->power_savings_balance = 0;
3344 * If a group is already running at full capacity or idle,
3345 * don't include that group in power savings calculations
3347 if (!sds->power_savings_balance ||
3348 sgs->sum_nr_running >= sgs->group_capacity ||
3349 !sgs->sum_nr_running)
3353 * Calculate the group which has the least non-idle load.
3354 * This is the group from where we need to pick up the load
3357 if ((sgs->sum_nr_running < sds->min_nr_running) ||
3358 (sgs->sum_nr_running == sds->min_nr_running &&
3359 group_first_cpu(group) > group_first_cpu(sds->group_min))) {
3360 sds->group_min = group;
3361 sds->min_nr_running = sgs->sum_nr_running;
3362 sds->min_load_per_task = sgs->sum_weighted_load /
3363 sgs->sum_nr_running;
3367 * Calculate the group which is almost near its
3368 * capacity but still has some space to pick up some load
3369 * from other group and save more power
3371 if (sgs->sum_nr_running > sgs->group_capacity - 1)
3374 if (sgs->sum_nr_running > sds->leader_nr_running ||
3375 (sgs->sum_nr_running == sds->leader_nr_running &&
3376 group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
3377 sds->group_leader = group;
3378 sds->leader_nr_running = sgs->sum_nr_running;
3383 * check_power_save_busiest_group - see if there is potential for some power-savings balance
3384 * @sds: Variable containing the statistics of the sched_domain
3385 * under consideration.
3386 * @this_cpu: Cpu at which we're currently performing load-balancing.
3387 * @imbalance: Variable to store the imbalance.
3390 * Check if we have potential to perform some power-savings balance.
3391 * If yes, set the busiest group to be the least loaded group in the
3392 * sched_domain, so that it's CPUs can be put to idle.
3394 * Returns 1 if there is potential to perform power-savings balance.
3397 static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
3398 int this_cpu, unsigned long *imbalance)
3400 if (!sds->power_savings_balance)
3403 if (sds->this != sds->group_leader ||
3404 sds->group_leader == sds->group_min)
3407 *imbalance = sds->min_load_per_task;
3408 sds->busiest = sds->group_min;
3410 if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
3411 cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
3412 group_first_cpu(sds->group_leader);
3418 #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3419 static inline void init_sd_power_savings_stats(struct sched_domain *sd,
3420 struct sd_lb_stats *sds, enum cpu_idle_type idle)
3425 static inline void update_sd_power_savings_stats(struct sched_group *group,
3426 struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
3431 static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
3432 int this_cpu, unsigned long *imbalance)
3436 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
3440 * update_sg_lb_stats - Update sched_group's statistics for load balancing.
3441 * @group: sched_group whose statistics are to be updated.
3442 * @this_cpu: Cpu for which load balance is currently performed.
3443 * @idle: Idle status of this_cpu
3444 * @load_idx: Load index of sched_domain of this_cpu for load calc.
3445 * @sd_idle: Idle status of the sched_domain containing group.
3446 * @local_group: Does group contain this_cpu.
3447 * @cpus: Set of cpus considered for load balancing.
3448 * @balance: Should we balance.
3449 * @sgs: variable to hold the statistics for this group.
3451 static inline void update_sg_lb_stats(struct sched_group *group, int this_cpu,
3452 enum cpu_idle_type idle, int load_idx, int *sd_idle,
3453 int local_group, const struct cpumask *cpus,
3454 int *balance, struct sg_lb_stats *sgs)
3456 unsigned long load, max_cpu_load, min_cpu_load;
3458 unsigned int balance_cpu = -1, first_idle_cpu = 0;
3459 unsigned long sum_avg_load_per_task;
3460 unsigned long avg_load_per_task;
3463 balance_cpu = group_first_cpu(group);
3465 /* Tally up the load of all CPUs in the group */
3466 sum_avg_load_per_task = avg_load_per_task = 0;
3468 min_cpu_load = ~0UL;
3470 for_each_cpu_and(i, sched_group_cpus(group), cpus) {
3471 struct rq *rq = cpu_rq(i);
3473 if (*sd_idle && rq->nr_running)
3476 /* Bias balancing toward cpus of our domain */
3478 if (idle_cpu(i) && !first_idle_cpu) {
3483 load = target_load(i, load_idx);
3485 load = source_load(i, load_idx);
3486 if (load > max_cpu_load)
3487 max_cpu_load = load;
3488 if (min_cpu_load > load)
3489 min_cpu_load = load;
3492 sgs->group_load += load;
3493 sgs->sum_nr_running += rq->nr_running;
3494 sgs->sum_weighted_load += weighted_cpuload(i);
3496 sum_avg_load_per_task += cpu_avg_load_per_task(i);
3500 * First idle cpu or the first cpu(busiest) in this sched group
3501 * is eligible for doing load balancing at this and above
3502 * domains. In the newly idle case, we will allow all the cpu's
3503 * to do the newly idle load balance.
3505 if (idle != CPU_NEWLY_IDLE && local_group &&
3506 balance_cpu != this_cpu && balance) {
3511 /* Adjust by relative CPU power of the group */
3512 sgs->avg_load = sg_div_cpu_power(group,
3513 sgs->group_load * SCHED_LOAD_SCALE);
3517 * Consider the group unbalanced when the imbalance is larger
3518 * than the average weight of two tasks.
3520 * APZ: with cgroup the avg task weight can vary wildly and
3521 * might not be a suitable number - should we keep a
3522 * normalized nr_running number somewhere that negates
3525 avg_load_per_task = sg_div_cpu_power(group,
3526 sum_avg_load_per_task * SCHED_LOAD_SCALE);
3528 if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
3531 sgs->group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
3536 * update_sd_lb_stats - Update sched_group's statistics for load balancing.
3537 * @sd: sched_domain whose statistics are to be updated.
3538 * @this_cpu: Cpu for which load balance is currently performed.
3539 * @idle: Idle status of this_cpu
3540 * @sd_idle: Idle status of the sched_domain containing group.
3541 * @cpus: Set of cpus considered for load balancing.
3542 * @balance: Should we balance.
3543 * @sds: variable to hold the statistics for this sched_domain.
3545 static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
3546 enum cpu_idle_type idle, int *sd_idle,
3547 const struct cpumask *cpus, int *balance,
3548 struct sd_lb_stats *sds)
3550 struct sched_group *group = sd->groups;
3551 struct sg_lb_stats sgs;
3554 init_sd_power_savings_stats(sd, sds, idle);
3555 load_idx = get_sd_load_idx(sd, idle);
3560 local_group = cpumask_test_cpu(this_cpu,
3561 sched_group_cpus(group));
3562 memset(&sgs, 0, sizeof(sgs));
3563 update_sg_lb_stats(group, this_cpu, idle, load_idx, sd_idle,
3564 local_group, cpus, balance, &sgs);
3566 if (local_group && balance && !(*balance))
3569 sds->total_load += sgs.group_load;
3570 sds->total_pwr += group->__cpu_power;
3573 sds->this_load = sgs.avg_load;
3575 sds->this_nr_running = sgs.sum_nr_running;
3576 sds->this_load_per_task = sgs.sum_weighted_load;
3577 } else if (sgs.avg_load > sds->max_load &&
3578 (sgs.sum_nr_running > sgs.group_capacity ||
3580 sds->max_load = sgs.avg_load;
3581 sds->busiest = group;
3582 sds->busiest_nr_running = sgs.sum_nr_running;
3583 sds->busiest_load_per_task = sgs.sum_weighted_load;
3584 sds->group_imb = sgs.group_imb;
3587 update_sd_power_savings_stats(group, sds, local_group, &sgs);
3588 group = group->next;
3589 } while (group != sd->groups);
3594 * fix_small_imbalance - Calculate the minor imbalance that exists
3595 * amongst the groups of a sched_domain, during
3597 * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
3598 * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
3599 * @imbalance: Variable to store the imbalance.
3601 static inline void fix_small_imbalance(struct sd_lb_stats *sds,
3602 int this_cpu, unsigned long *imbalance)
3604 unsigned long tmp, pwr_now = 0, pwr_move = 0;
3605 unsigned int imbn = 2;
3607 if (sds->this_nr_running) {
3608 sds->this_load_per_task /= sds->this_nr_running;
3609 if (sds->busiest_load_per_task >
3610 sds->this_load_per_task)
3613 sds->this_load_per_task =
3614 cpu_avg_load_per_task(this_cpu);
3616 if (sds->max_load - sds->this_load + sds->busiest_load_per_task >=
3617 sds->busiest_load_per_task * imbn) {
3618 *imbalance = sds->busiest_load_per_task;
3623 * OK, we don't have enough imbalance to justify moving tasks,
3624 * however we may be able to increase total CPU power used by
3628 pwr_now += sds->busiest->__cpu_power *
3629 min(sds->busiest_load_per_task, sds->max_load);
3630 pwr_now += sds->this->__cpu_power *
3631 min(sds->this_load_per_task, sds->this_load);
3632 pwr_now /= SCHED_LOAD_SCALE;
3634 /* Amount of load we'd subtract */
3635 tmp = sg_div_cpu_power(sds->busiest,
3636 sds->busiest_load_per_task * SCHED_LOAD_SCALE);
3637 if (sds->max_load > tmp)
3638 pwr_move += sds->busiest->__cpu_power *
3639 min(sds->busiest_load_per_task, sds->max_load - tmp);
3641 /* Amount of load we'd add */
3642 if (sds->max_load * sds->busiest->__cpu_power <
3643 sds->busiest_load_per_task * SCHED_LOAD_SCALE)
3644 tmp = sg_div_cpu_power(sds->this,
3645 sds->max_load * sds->busiest->__cpu_power);
3647 tmp = sg_div_cpu_power(sds->this,
3648 sds->busiest_load_per_task * SCHED_LOAD_SCALE);
3649 pwr_move += sds->this->__cpu_power *
3650 min(sds->this_load_per_task, sds->this_load + tmp);
3651 pwr_move /= SCHED_LOAD_SCALE;
3653 /* Move if we gain throughput */
3654 if (pwr_move > pwr_now)
3655 *imbalance = sds->busiest_load_per_task;
3659 * calculate_imbalance - Calculate the amount of imbalance present within the
3660 * groups of a given sched_domain during load balance.
3661 * @sds: statistics of the sched_domain whose imbalance is to be calculated.
3662 * @this_cpu: Cpu for which currently load balance is being performed.
3663 * @imbalance: The variable to store the imbalance.
3665 static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
3666 unsigned long *imbalance)
3668 unsigned long max_pull;
3670 * In the presence of smp nice balancing, certain scenarios can have
3671 * max load less than avg load(as we skip the groups at or below
3672 * its cpu_power, while calculating max_load..)
3674 if (sds->max_load < sds->avg_load) {
3676 return fix_small_imbalance(sds, this_cpu, imbalance);
3679 /* Don't want to pull so many tasks that a group would go idle */
3680 max_pull = min(sds->max_load - sds->avg_load,
3681 sds->max_load - sds->busiest_load_per_task);
3683 /* How much load to actually move to equalise the imbalance */
3684 *imbalance = min(max_pull * sds->busiest->__cpu_power,
3685 (sds->avg_load - sds->this_load) * sds->this->__cpu_power)
3689 * if *imbalance is less than the average load per runnable task
3690 * there is no gaurantee that any tasks will be moved so we'll have
3691 * a think about bumping its value to force at least one task to be
3694 if (*imbalance < sds->busiest_load_per_task)
3695 return fix_small_imbalance(sds, this_cpu, imbalance);
3698 /******* find_busiest_group() helpers end here *********************/
3701 * find_busiest_group - Returns the busiest group within the sched_domain
3702 * if there is an imbalance. If there isn't an imbalance, and
3703 * the user has opted for power-savings, it returns a group whose
3704 * CPUs can be put to idle by rebalancing those tasks elsewhere, if
3705 * such a group exists.
3707 * Also calculates the amount of weighted load which should be moved
3708 * to restore balance.
3710 * @sd: The sched_domain whose busiest group is to be returned.
3711 * @this_cpu: The cpu for which load balancing is currently being performed.
3712 * @imbalance: Variable which stores amount of weighted load which should
3713 * be moved to restore balance/put a group to idle.
3714 * @idle: The idle status of this_cpu.
3715 * @sd_idle: The idleness of sd
3716 * @cpus: The set of CPUs under consideration for load-balancing.
3717 * @balance: Pointer to a variable indicating if this_cpu
3718 * is the appropriate cpu to perform load balancing at this_level.
3720 * Returns: - the busiest group if imbalance exists.
3721 * - If no imbalance and user has opted for power-savings balance,
3722 * return the least loaded group whose CPUs can be
3723 * put to idle by rebalancing its tasks onto our group.
3725 static struct sched_group *
3726 find_busiest_group(struct sched_domain *sd, int this_cpu,
3727 unsigned long *imbalance, enum cpu_idle_type idle,
3728 int *sd_idle, const struct cpumask *cpus, int *balance)
3730 struct sd_lb_stats sds;
3732 memset(&sds, 0, sizeof(sds));
3735 * Compute the various statistics relavent for load balancing at
3738 update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus,
3741 /* Cases where imbalance does not exist from POV of this_cpu */
3742 /* 1) this_cpu is not the appropriate cpu to perform load balancing
3744 * 2) There is no busy sibling group to pull from.
3745 * 3) This group is the busiest group.
3746 * 4) This group is more busy than the avg busieness at this
3748 * 5) The imbalance is within the specified limit.
3749 * 6) Any rebalance would lead to ping-pong
3751 if (balance && !(*balance))
3754 if (!sds.busiest || sds.busiest_nr_running == 0)
3757 if (sds.this_load >= sds.max_load)
3760 sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
3762 if (sds.this_load >= sds.avg_load)
3765 if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
3768 sds.busiest_load_per_task /= sds.busiest_nr_running;
3770 sds.busiest_load_per_task =
3771 min(sds.busiest_load_per_task, sds.avg_load);
3774 * We're trying to get all the cpus to the average_load, so we don't
3775 * want to push ourselves above the average load, nor do we wish to
3776 * reduce the max loaded cpu below the average load, as either of these
3777 * actions would just result in more rebalancing later, and ping-pong
3778 * tasks around. Thus we look for the minimum possible imbalance.
3779 * Negative imbalances (*we* are more loaded than anyone else) will
3780 * be counted as no imbalance for these purposes -- we can't fix that
3781 * by pulling tasks to us. Be careful of negative numbers as they'll
3782 * appear as very large values with unsigned longs.
3784 if (sds.max_load <= sds.busiest_load_per_task)
3787 /* Looks like there is an imbalance. Compute it */
3788 calculate_imbalance(&sds, this_cpu, imbalance);
3793 * There is no obvious imbalance. But check if we can do some balancing
3796 if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
3804 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3807 find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
3808 unsigned long imbalance, const struct cpumask *cpus)
3810 struct rq *busiest = NULL, *rq;
3811 unsigned long max_load = 0;
3814 for_each_cpu(i, sched_group_cpus(group)) {
3817 if (!cpumask_test_cpu(i, cpus))
3821 wl = weighted_cpuload(i);
3823 if (rq->nr_running == 1 && wl > imbalance)
3826 if (wl > max_load) {
3836 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3837 * so long as it is large enough.
3839 #define MAX_PINNED_INTERVAL 512
3841 /* Working cpumask for load_balance and load_balance_newidle. */
3842 static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
3845 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3846 * tasks if there is an imbalance.
3848 static int load_balance(int this_cpu, struct rq *this_rq,
3849 struct sched_domain *sd, enum cpu_idle_type idle,
3852 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
3853 struct sched_group *group;
3854 unsigned long imbalance;
3856 unsigned long flags;
3857 struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
3859 cpumask_setall(cpus);
3862 * When power savings policy is enabled for the parent domain, idle
3863 * sibling can pick up load irrespective of busy siblings. In this case,
3864 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3865 * portraying it as CPU_NOT_IDLE.
3867 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
3868 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3871 schedstat_inc(sd, lb_count[idle]);
3875 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
3882 schedstat_inc(sd, lb_nobusyg[idle]);
3886 busiest = find_busiest_queue(group, idle, imbalance, cpus);
3888 schedstat_inc(sd, lb_nobusyq[idle]);
3892 BUG_ON(busiest == this_rq);
3894 schedstat_add(sd, lb_imbalance[idle], imbalance);
3897 if (busiest->nr_running > 1) {
3899 * Attempt to move tasks. If find_busiest_group has found
3900 * an imbalance but busiest->nr_running <= 1, the group is
3901 * still unbalanced. ld_moved simply stays zero, so it is
3902 * correctly treated as an imbalance.
3904 local_irq_save(flags);
3905 double_rq_lock(this_rq, busiest);
3906 ld_moved = move_tasks(this_rq, this_cpu, busiest,
3907 imbalance, sd, idle, &all_pinned);
3908 double_rq_unlock(this_rq, busiest);
3909 local_irq_restore(flags);
3912 * some other cpu did the load balance for us.
3914 if (ld_moved && this_cpu != smp_processor_id())
3915 resched_cpu(this_cpu);
3917 /* All tasks on this runqueue were pinned by CPU affinity */
3918 if (unlikely(all_pinned)) {
3919 cpumask_clear_cpu(cpu_of(busiest), cpus);
3920 if (!cpumask_empty(cpus))
3927 schedstat_inc(sd, lb_failed[idle]);
3928 sd->nr_balance_failed++;
3930 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
3932 spin_lock_irqsave(&busiest->lock, flags);
3934 /* don't kick the migration_thread, if the curr
3935 * task on busiest cpu can't be moved to this_cpu
3937 if (!cpumask_test_cpu(this_cpu,
3938 &busiest->curr->cpus_allowed)) {
3939 spin_unlock_irqrestore(&busiest->lock, flags);
3941 goto out_one_pinned;
3944 if (!busiest->active_balance) {
3945 busiest->active_balance = 1;
3946 busiest->push_cpu = this_cpu;
3949 spin_unlock_irqrestore(&busiest->lock, flags);
3951 wake_up_process(busiest->migration_thread);
3954 * We've kicked active balancing, reset the failure
3957 sd->nr_balance_failed = sd->cache_nice_tries+1;
3960 sd->nr_balance_failed = 0;
3962 if (likely(!active_balance)) {
3963 /* We were unbalanced, so reset the balancing interval */
3964 sd->balance_interval = sd->min_interval;
3967 * If we've begun active balancing, start to back off. This
3968 * case may not be covered by the all_pinned logic if there
3969 * is only 1 task on the busy runqueue (because we don't call
3972 if (sd->balance_interval < sd->max_interval)
3973 sd->balance_interval *= 2;
3976 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3977 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
3983 schedstat_inc(sd, lb_balanced[idle]);
3985 sd->nr_balance_failed = 0;
3988 /* tune up the balancing interval */
3989 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
3990 (sd->balance_interval < sd->max_interval))
3991 sd->balance_interval *= 2;
3993 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3994 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4005 * Check this_cpu to ensure it is balanced within domain. Attempt to move
4006 * tasks if there is an imbalance.
4008 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
4009 * this_rq is locked.
4012 load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
4014 struct sched_group *group;
4015 struct rq *busiest = NULL;
4016 unsigned long imbalance;
4020 struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
4022 cpumask_setall(cpus);
4025 * When power savings policy is enabled for the parent domain, idle
4026 * sibling can pick up load irrespective of busy siblings. In this case,
4027 * let the state of idle sibling percolate up as IDLE, instead of
4028 * portraying it as CPU_NOT_IDLE.
4030 if (sd->flags & SD_SHARE_CPUPOWER &&
4031 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4034 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
4036 update_shares_locked(this_rq, sd);
4037 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
4038 &sd_idle, cpus, NULL);
4040 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
4044 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
4046 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
4050 BUG_ON(busiest == this_rq);
4052 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
4055 if (busiest->nr_running > 1) {
4056 /* Attempt to move tasks */
4057 double_lock_balance(this_rq, busiest);
4058 /* this_rq->clock is already updated */
4059 update_rq_clock(busiest);
4060 ld_moved = move_tasks(this_rq, this_cpu, busiest,
4061 imbalance, sd, CPU_NEWLY_IDLE,
4063 double_unlock_balance(this_rq, busiest);
4065 if (unlikely(all_pinned)) {
4066 cpumask_clear_cpu(cpu_of(busiest), cpus);
4067 if (!cpumask_empty(cpus))
4073 int active_balance = 0;
4075 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
4076 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4077 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4080 if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
4083 if (sd->nr_balance_failed++ < 2)
4087 * The only task running in a non-idle cpu can be moved to this
4088 * cpu in an attempt to completely freeup the other CPU
4089 * package. The same method used to move task in load_balance()
4090 * have been extended for load_balance_newidle() to speedup
4091 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
4093 * The package power saving logic comes from
4094 * find_busiest_group(). If there are no imbalance, then
4095 * f_b_g() will return NULL. However when sched_mc={1,2} then
4096 * f_b_g() will select a group from which a running task may be
4097 * pulled to this cpu in order to make the other package idle.
4098 * If there is no opportunity to make a package idle and if
4099 * there are no imbalance, then f_b_g() will return NULL and no
4100 * action will be taken in load_balance_newidle().
4102 * Under normal task pull operation due to imbalance, there
4103 * will be more than one task in the source run queue and
4104 * move_tasks() will succeed. ld_moved will be true and this
4105 * active balance code will not be triggered.
4108 /* Lock busiest in correct order while this_rq is held */
4109 double_lock_balance(this_rq, busiest);
4112 * don't kick the migration_thread, if the curr
4113 * task on busiest cpu can't be moved to this_cpu
4115 if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) {
4116 double_unlock_balance(this_rq, busiest);
4121 if (!busiest->active_balance) {
4122 busiest->active_balance = 1;
4123 busiest->push_cpu = this_cpu;
4127 double_unlock_balance(this_rq, busiest);
4129 * Should not call ttwu while holding a rq->lock
4131 spin_unlock(&this_rq->lock);
4133 wake_up_process(busiest->migration_thread);
4134 spin_lock(&this_rq->lock);
4137 sd->nr_balance_failed = 0;
4139 update_shares_locked(this_rq, sd);
4143 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
4144 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
4145 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
4147 sd->nr_balance_failed = 0;
4153 * idle_balance is called by schedule() if this_cpu is about to become
4154 * idle. Attempts to pull tasks from other CPUs.
4156 static void idle_balance(int this_cpu, struct rq *this_rq)
4158 struct sched_domain *sd;
4159 int pulled_task = 0;
4160 unsigned long next_balance = jiffies + HZ;
4162 for_each_domain(this_cpu, sd) {
4163 unsigned long interval;
4165 if (!(sd->flags & SD_LOAD_BALANCE))
4168 if (sd->flags & SD_BALANCE_NEWIDLE)
4169 /* If we've pulled tasks over stop searching: */
4170 pulled_task = load_balance_newidle(this_cpu, this_rq,
4173 interval = msecs_to_jiffies(sd->balance_interval);
4174 if (time_after(next_balance, sd->last_balance + interval))
4175 next_balance = sd->last_balance + interval;
4179 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
4181 * We are going idle. next_balance may be set based on
4182 * a busy processor. So reset next_balance.
4184 this_rq->next_balance = next_balance;
4189 * active_load_balance is run by migration threads. It pushes running tasks
4190 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
4191 * running on each physical CPU where possible, and avoids physical /
4192 * logical imbalances.
4194 * Called with busiest_rq locked.
4196 static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
4198 int target_cpu = busiest_rq->push_cpu;
4199 struct sched_domain *sd;
4200 struct rq *target_rq;
4202 /* Is there any task to move? */
4203 if (busiest_rq->nr_running <= 1)
4206 target_rq = cpu_rq(target_cpu);
4209 * This condition is "impossible", if it occurs
4210 * we need to fix it. Originally reported by
4211 * Bjorn Helgaas on a 128-cpu setup.
4213 BUG_ON(busiest_rq == target_rq);
4215 /* move a task from busiest_rq to target_rq */
4216 double_lock_balance(busiest_rq, target_rq);
4217 update_rq_clock(busiest_rq);
4218 update_rq_clock(target_rq);
4220 /* Search for an sd spanning us and the target CPU. */
4221 for_each_domain(target_cpu, sd) {
4222 if ((sd->flags & SD_LOAD_BALANCE) &&
4223 cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
4228 schedstat_inc(sd, alb_count);
4230 if (move_one_task(target_rq, target_cpu, busiest_rq,
4232 schedstat_inc(sd, alb_pushed);
4234 schedstat_inc(sd, alb_failed);
4236 double_unlock_balance(busiest_rq, target_rq);
4241 atomic_t load_balancer;
4242 cpumask_var_t cpu_mask;
4243 } nohz ____cacheline_aligned = {
4244 .load_balancer = ATOMIC_INIT(-1),
4247 int get_nohz_load_balancer(void)
4249 return atomic_read(&nohz.load_balancer);
4253 * This routine will try to nominate the ilb (idle load balancing)
4254 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4255 * load balancing on behalf of all those cpus. If all the cpus in the system
4256 * go into this tickless mode, then there will be no ilb owner (as there is
4257 * no need for one) and all the cpus will sleep till the next wakeup event
4260 * For the ilb owner, tick is not stopped. And this tick will be used
4261 * for idle load balancing. ilb owner will still be part of
4264 * While stopping the tick, this cpu will become the ilb owner if there
4265 * is no other owner. And will be the owner till that cpu becomes busy
4266 * or if all cpus in the system stop their ticks at which point
4267 * there is no need for ilb owner.
4269 * When the ilb owner becomes busy, it nominates another owner, during the
4270 * next busy scheduler_tick()
4272 int select_nohz_load_balancer(int stop_tick)
4274 int cpu = smp_processor_id();
4277 cpu_rq(cpu)->in_nohz_recently = 1;
4279 if (!cpu_active(cpu)) {
4280 if (atomic_read(&nohz.load_balancer) != cpu)
4284 * If we are going offline and still the leader,
4287 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
4293 cpumask_set_cpu(cpu, nohz.cpu_mask);
4295 /* time for ilb owner also to sleep */
4296 if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
4297 if (atomic_read(&nohz.load_balancer) == cpu)
4298 atomic_set(&nohz.load_balancer, -1);
4302 if (atomic_read(&nohz.load_balancer) == -1) {
4303 /* make me the ilb owner */
4304 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
4306 } else if (atomic_read(&nohz.load_balancer) == cpu)
4309 if (!cpumask_test_cpu(cpu, nohz.cpu_mask))
4312 cpumask_clear_cpu(cpu, nohz.cpu_mask);
4314 if (atomic_read(&nohz.load_balancer) == cpu)
4315 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
4322 static DEFINE_SPINLOCK(balancing);
4325 * It checks each scheduling domain to see if it is due to be balanced,
4326 * and initiates a balancing operation if so.
4328 * Balancing parameters are set up in arch_init_sched_domains.
4330 static void rebalance_domains(int cpu, enum cpu_idle_type idle)
4333 struct rq *rq = cpu_rq(cpu);
4334 unsigned long interval;
4335 struct sched_domain *sd;
4336 /* Earliest time when we have to do rebalance again */
4337 unsigned long next_balance = jiffies + 60*HZ;
4338 int update_next_balance = 0;
4341 for_each_domain(cpu, sd) {
4342 if (!(sd->flags & SD_LOAD_BALANCE))
4345 interval = sd->balance_interval;
4346 if (idle != CPU_IDLE)
4347 interval *= sd->busy_factor;
4349 /* scale ms to jiffies */
4350 interval = msecs_to_jiffies(interval);
4351 if (unlikely(!interval))
4353 if (interval > HZ*NR_CPUS/10)
4354 interval = HZ*NR_CPUS/10;
4356 need_serialize = sd->flags & SD_SERIALIZE;
4358 if (need_serialize) {
4359 if (!spin_trylock(&balancing))
4363 if (time_after_eq(jiffies, sd->last_balance + interval)) {
4364 if (load_balance(cpu, rq, sd, idle, &balance)) {
4366 * We've pulled tasks over so either we're no
4367 * longer idle, or one of our SMT siblings is
4370 idle = CPU_NOT_IDLE;
4372 sd->last_balance = jiffies;
4375 spin_unlock(&balancing);
4377 if (time_after(next_balance, sd->last_balance + interval)) {
4378 next_balance = sd->last_balance + interval;
4379 update_next_balance = 1;
4383 * Stop the load balance at this level. There is another
4384 * CPU in our sched group which is doing load balancing more
4392 * next_balance will be updated only when there is a need.
4393 * When the cpu is attached to null domain for ex, it will not be
4396 if (likely(update_next_balance))
4397 rq->next_balance = next_balance;
4401 * run_rebalance_domains is triggered when needed from the scheduler tick.
4402 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4403 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4405 static void run_rebalance_domains(struct softirq_action *h)
4407 int this_cpu = smp_processor_id();
4408 struct rq *this_rq = cpu_rq(this_cpu);
4409 enum cpu_idle_type idle = this_rq->idle_at_tick ?
4410 CPU_IDLE : CPU_NOT_IDLE;
4412 rebalance_domains(this_cpu, idle);
4416 * If this cpu is the owner for idle load balancing, then do the
4417 * balancing on behalf of the other idle cpus whose ticks are
4420 if (this_rq->idle_at_tick &&
4421 atomic_read(&nohz.load_balancer) == this_cpu) {
4425 for_each_cpu(balance_cpu, nohz.cpu_mask) {
4426 if (balance_cpu == this_cpu)
4430 * If this cpu gets work to do, stop the load balancing
4431 * work being done for other cpus. Next load
4432 * balancing owner will pick it up.
4437 rebalance_domains(balance_cpu, CPU_IDLE);
4439 rq = cpu_rq(balance_cpu);
4440 if (time_after(this_rq->next_balance, rq->next_balance))
4441 this_rq->next_balance = rq->next_balance;
4447 static inline int on_null_domain(int cpu)
4449 return !rcu_dereference(cpu_rq(cpu)->sd);
4453 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4455 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4456 * idle load balancing owner or decide to stop the periodic load balancing,
4457 * if the whole system is idle.
4459 static inline void trigger_load_balance(struct rq *rq, int cpu)
4463 * If we were in the nohz mode recently and busy at the current
4464 * scheduler tick, then check if we need to nominate new idle
4467 if (rq->in_nohz_recently && !rq->idle_at_tick) {
4468 rq->in_nohz_recently = 0;
4470 if (atomic_read(&nohz.load_balancer) == cpu) {
4471 cpumask_clear_cpu(cpu, nohz.cpu_mask);
4472 atomic_set(&nohz.load_balancer, -1);
4475 if (atomic_read(&nohz.load_balancer) == -1) {
4477 * simple selection for now: Nominate the
4478 * first cpu in the nohz list to be the next
4481 * TBD: Traverse the sched domains and nominate
4482 * the nearest cpu in the nohz.cpu_mask.
4484 int ilb = cpumask_first(nohz.cpu_mask);
4486 if (ilb < nr_cpu_ids)
4492 * If this cpu is idle and doing idle load balancing for all the
4493 * cpus with ticks stopped, is it time for that to stop?
4495 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
4496 cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
4502 * If this cpu is idle and the idle load balancing is done by
4503 * someone else, then no need raise the SCHED_SOFTIRQ
4505 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
4506 cpumask_test_cpu(cpu, nohz.cpu_mask))
4509 /* Don't need to rebalance while attached to NULL domain */
4510 if (time_after_eq(jiffies, rq->next_balance) &&
4511 likely(!on_null_domain(cpu)))
4512 raise_softirq(SCHED_SOFTIRQ);
4515 #else /* CONFIG_SMP */
4518 * on UP we do not need to balance between CPUs:
4520 static inline void idle_balance(int cpu, struct rq *rq)
4526 DEFINE_PER_CPU(struct kernel_stat, kstat);
4528 EXPORT_PER_CPU_SYMBOL(kstat);
4531 * Return any ns on the sched_clock that have not yet been accounted in
4532 * @p in case that task is currently running.
4534 * Called with task_rq_lock() held on @rq.
4536 static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
4540 if (task_current(rq, p)) {
4541 update_rq_clock(rq);
4542 ns = rq->clock - p->se.exec_start;
4550 unsigned long long task_delta_exec(struct task_struct *p)
4552 unsigned long flags;
4556 rq = task_rq_lock(p, &flags);
4557 ns = do_task_delta_exec(p, rq);
4558 task_rq_unlock(rq, &flags);
4564 * Return accounted runtime for the task.
4565 * In case the task is currently running, return the runtime plus current's
4566 * pending runtime that have not been accounted yet.
4568 unsigned long long task_sched_runtime(struct task_struct *p)
4570 unsigned long flags;
4574 rq = task_rq_lock(p, &flags);
4575 ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
4576 task_rq_unlock(rq, &flags);
4582 * Return sum_exec_runtime for the thread group.
4583 * In case the task is currently running, return the sum plus current's
4584 * pending runtime that have not been accounted yet.
4586 * Note that the thread group might have other running tasks as well,
4587 * so the return value not includes other pending runtime that other
4588 * running tasks might have.
4590 unsigned long long thread_group_sched_runtime(struct task_struct *p)
4592 struct task_cputime totals;
4593 unsigned long flags;
4597 rq = task_rq_lock(p, &flags);
4598 thread_group_cputime(p, &totals);
4599 ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq);
4600 task_rq_unlock(rq, &flags);
4606 * Account user cpu time to a process.
4607 * @p: the process that the cpu time gets accounted to
4608 * @cputime: the cpu time spent in user space since the last update
4609 * @cputime_scaled: cputime scaled by cpu frequency
4611 void account_user_time(struct task_struct *p, cputime_t cputime,
4612 cputime_t cputime_scaled)
4614 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4617 /* Add user time to process. */
4618 p->utime = cputime_add(p->utime, cputime);
4619 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4620 account_group_user_time(p, cputime);
4622 /* Add user time to cpustat. */
4623 tmp = cputime_to_cputime64(cputime);
4624 if (TASK_NICE(p) > 0)
4625 cpustat->nice = cputime64_add(cpustat->nice, tmp);
4627 cpustat->user = cputime64_add(cpustat->user, tmp);
4629 cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime);
4630 /* Account for user time used */
4631 acct_update_integrals(p);
4635 * Account guest cpu time to a process.
4636 * @p: the process that the cpu time gets accounted to
4637 * @cputime: the cpu time spent in virtual machine since the last update
4638 * @cputime_scaled: cputime scaled by cpu frequency
4640 static void account_guest_time(struct task_struct *p, cputime_t cputime,
4641 cputime_t cputime_scaled)
4644 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4646 tmp = cputime_to_cputime64(cputime);
4648 /* Add guest time to process. */
4649 p->utime = cputime_add(p->utime, cputime);
4650 p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
4651 account_group_user_time(p, cputime);
4652 p->gtime = cputime_add(p->gtime, cputime);
4654 /* Add guest time to cpustat. */
4655 cpustat->user = cputime64_add(cpustat->user, tmp);
4656 cpustat->guest = cputime64_add(cpustat->guest, tmp);
4660 * Account system cpu time to a process.
4661 * @p: the process that the cpu time gets accounted to
4662 * @hardirq_offset: the offset to subtract from hardirq_count()
4663 * @cputime: the cpu time spent in kernel space since the last update
4664 * @cputime_scaled: cputime scaled by cpu frequency
4666 void account_system_time(struct task_struct *p, int hardirq_offset,
4667 cputime_t cputime, cputime_t cputime_scaled)
4669 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4672 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
4673 account_guest_time(p, cputime, cputime_scaled);
4677 /* Add system time to process. */
4678 p->stime = cputime_add(p->stime, cputime);
4679 p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
4680 account_group_system_time(p, cputime);
4682 /* Add system time to cpustat. */
4683 tmp = cputime_to_cputime64(cputime);
4684 if (hardirq_count() - hardirq_offset)
4685 cpustat->irq = cputime64_add(cpustat->irq, tmp);
4686 else if (softirq_count())
4687 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
4689 cpustat->system = cputime64_add(cpustat->system, tmp);
4691 cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
4693 /* Account for system time used */
4694 acct_update_integrals(p);
4698 * Account for involuntary wait time.
4699 * @steal: the cpu time spent in involuntary wait
4701 void account_steal_time(cputime_t cputime)
4703 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4704 cputime64_t cputime64 = cputime_to_cputime64(cputime);
4706 cpustat->steal = cputime64_add(cpustat->steal, cputime64);
4710 * Account for idle time.
4711 * @cputime: the cpu time spent in idle wait
4713 void account_idle_time(cputime_t cputime)
4715 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
4716 cputime64_t cputime64 = cputime_to_cputime64(cputime);
4717 struct rq *rq = this_rq();
4719 if (atomic_read(&rq->nr_iowait) > 0)
4720 cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
4722 cpustat->idle = cputime64_add(cpustat->idle, cputime64);
4725 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4728 * Account a single tick of cpu time.
4729 * @p: the process that the cpu time gets accounted to
4730 * @user_tick: indicates if the tick is a user or a system tick
4732 void account_process_tick(struct task_struct *p, int user_tick)
4734 cputime_t one_jiffy = jiffies_to_cputime(1);
4735 cputime_t one_jiffy_scaled = cputime_to_scaled(one_jiffy);
4736 struct rq *rq = this_rq();
4739 account_user_time(p, one_jiffy, one_jiffy_scaled);
4740 else if (p != rq->idle)
4741 account_system_time(p, HARDIRQ_OFFSET, one_jiffy,
4744 account_idle_time(one_jiffy);
4748 * Account multiple ticks of steal time.
4749 * @p: the process from which the cpu time has been stolen
4750 * @ticks: number of stolen ticks
4752 void account_steal_ticks(unsigned long ticks)
4754 account_steal_time(jiffies_to_cputime(ticks));
4758 * Account multiple ticks of idle time.
4759 * @ticks: number of stolen ticks
4761 void account_idle_ticks(unsigned long ticks)
4763 account_idle_time(jiffies_to_cputime(ticks));
4769 * Use precise platform statistics if available:
4771 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4772 cputime_t task_utime(struct task_struct *p)
4777 cputime_t task_stime(struct task_struct *p)
4782 cputime_t task_utime(struct task_struct *p)
4784 clock_t utime = cputime_to_clock_t(p->utime),
4785 total = utime + cputime_to_clock_t(p->stime);
4789 * Use CFS's precise accounting:
4791 temp = (u64)nsec_to_clock_t(p->se.sum_exec_runtime);
4795 do_div(temp, total);
4797 utime = (clock_t)temp;
4799 p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime));
4800 return p->prev_utime;
4803 cputime_t task_stime(struct task_struct *p)
4808 * Use CFS's precise accounting. (we subtract utime from
4809 * the total, to make sure the total observed by userspace
4810 * grows monotonically - apps rely on that):
4812 stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
4813 cputime_to_clock_t(task_utime(p));
4816 p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime));
4818 return p->prev_stime;
4822 inline cputime_t task_gtime(struct task_struct *p)
4828 * This function gets called by the timer code, with HZ frequency.
4829 * We call it with interrupts disabled.
4831 * It also gets called by the fork code, when changing the parent's
4834 void scheduler_tick(void)
4836 int cpu = smp_processor_id();
4837 struct rq *rq = cpu_rq(cpu);
4838 struct task_struct *curr = rq->curr;
4842 spin_lock(&rq->lock);
4843 update_rq_clock(rq);
4844 update_cpu_load(rq);
4845 curr->sched_class->task_tick(rq, curr, 0);
4846 spin_unlock(&rq->lock);
4849 rq->idle_at_tick = idle_cpu(cpu);
4850 trigger_load_balance(rq, cpu);
4854 notrace unsigned long get_parent_ip(unsigned long addr)
4856 if (in_lock_functions(addr)) {
4857 addr = CALLER_ADDR2;
4858 if (in_lock_functions(addr))
4859 addr = CALLER_ADDR3;
4864 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4865 defined(CONFIG_PREEMPT_TRACER))
4867 void __kprobes add_preempt_count(int val)
4869 #ifdef CONFIG_DEBUG_PREEMPT
4873 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4876 preempt_count() += val;
4877 #ifdef CONFIG_DEBUG_PREEMPT
4879 * Spinlock count overflowing soon?
4881 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
4884 if (preempt_count() == val)
4885 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4887 EXPORT_SYMBOL(add_preempt_count);
4889 void __kprobes sub_preempt_count(int val)
4891 #ifdef CONFIG_DEBUG_PREEMPT
4895 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
4898 * Is the spinlock portion underflowing?
4900 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
4901 !(preempt_count() & PREEMPT_MASK)))
4905 if (preempt_count() == val)
4906 trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
4907 preempt_count() -= val;
4909 EXPORT_SYMBOL(sub_preempt_count);
4914 * Print scheduling while atomic bug:
4916 static noinline void __schedule_bug(struct task_struct *prev)
4918 struct pt_regs *regs = get_irq_regs();
4920 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
4921 prev->comm, prev->pid, preempt_count());
4923 debug_show_held_locks(prev);
4925 if (irqs_disabled())
4926 print_irqtrace_events(prev);
4935 * Various schedule()-time debugging checks and statistics:
4937 static inline void schedule_debug(struct task_struct *prev)
4940 * Test if we are atomic. Since do_exit() needs to call into
4941 * schedule() atomically, we ignore that path for now.
4942 * Otherwise, whine if we are scheduling when we should not be.
4944 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
4945 __schedule_bug(prev);
4947 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
4949 schedstat_inc(this_rq(), sched_count);
4950 #ifdef CONFIG_SCHEDSTATS
4951 if (unlikely(prev->lock_depth >= 0)) {
4952 schedstat_inc(this_rq(), bkl_count);
4953 schedstat_inc(prev, sched_info.bkl_count);
4958 static void put_prev_task(struct rq *rq, struct task_struct *prev)
4960 if (prev->state == TASK_RUNNING) {
4961 u64 runtime = prev->se.sum_exec_runtime;
4963 runtime -= prev->se.prev_sum_exec_runtime;
4964 runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
4967 * In order to avoid avg_overlap growing stale when we are
4968 * indeed overlapping and hence not getting put to sleep, grow
4969 * the avg_overlap on preemption.
4971 * We use the average preemption runtime because that
4972 * correlates to the amount of cache footprint a task can
4975 update_avg(&prev->se.avg_overlap, runtime);
4977 prev->sched_class->put_prev_task(rq, prev);
4981 * Pick up the highest-prio task:
4983 static inline struct task_struct *
4984 pick_next_task(struct rq *rq)
4986 const struct sched_class *class;
4987 struct task_struct *p;
4990 * Optimization: we know that if all tasks are in
4991 * the fair class we can call that function directly:
4993 if (likely(rq->nr_running == rq->cfs.nr_running)) {
4994 p = fair_sched_class.pick_next_task(rq);
4999 class = sched_class_highest;
5001 p = class->pick_next_task(rq);
5005 * Will never be NULL as the idle class always
5006 * returns a non-NULL p:
5008 class = class->next;
5013 * schedule() is the main scheduler function.
5015 asmlinkage void __sched __schedule(void)
5017 struct task_struct *prev, *next;
5018 unsigned long *switch_count;
5022 cpu = smp_processor_id();
5026 switch_count = &prev->nivcsw;
5028 release_kernel_lock(prev);
5029 need_resched_nonpreemptible:
5031 schedule_debug(prev);
5033 if (sched_feat(HRTICK))
5036 spin_lock_irq(&rq->lock);
5037 update_rq_clock(rq);
5038 clear_tsk_need_resched(prev);
5040 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
5041 if (unlikely(signal_pending_state(prev->state, prev)))
5042 prev->state = TASK_RUNNING;
5044 deactivate_task(rq, prev, 1);
5045 switch_count = &prev->nvcsw;
5049 if (prev->sched_class->pre_schedule)
5050 prev->sched_class->pre_schedule(rq, prev);
5053 if (unlikely(!rq->nr_running))
5054 idle_balance(cpu, rq);
5056 put_prev_task(rq, prev);
5057 next = pick_next_task(rq);
5059 if (likely(prev != next)) {
5060 sched_info_switch(prev, next);
5066 context_switch(rq, prev, next); /* unlocks the rq */
5068 * the context switch might have flipped the stack from under
5069 * us, hence refresh the local variables.
5071 cpu = smp_processor_id();
5074 spin_unlock_irq(&rq->lock);
5076 if (unlikely(reacquire_kernel_lock(current) < 0))
5077 goto need_resched_nonpreemptible;
5080 asmlinkage void __sched schedule(void)
5085 preempt_enable_no_resched();
5086 if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
5089 EXPORT_SYMBOL(schedule);
5093 * Look out! "owner" is an entirely speculative pointer
5094 * access and not reliable.
5096 int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
5101 if (!sched_feat(OWNER_SPIN))
5104 #ifdef CONFIG_DEBUG_PAGEALLOC
5106 * Need to access the cpu field knowing that
5107 * DEBUG_PAGEALLOC could have unmapped it if
5108 * the mutex owner just released it and exited.
5110 if (probe_kernel_address(&owner->cpu, cpu))
5117 * Even if the access succeeded (likely case),
5118 * the cpu field may no longer be valid.
5120 if (cpu >= nr_cpumask_bits)
5124 * We need to validate that we can do a
5125 * get_cpu() and that we have the percpu area.
5127 if (!cpu_online(cpu))
5134 * Owner changed, break to re-assess state.
5136 if (lock->owner != owner)
5140 * Is that owner really running on that cpu?
5142 if (task_thread_info(rq->curr) != owner || need_resched())
5152 #ifdef CONFIG_PREEMPT
5154 * this is the entry point to schedule() from in-kernel preemption
5155 * off of preempt_enable. Kernel preemptions off return from interrupt
5156 * occur there and call schedule directly.
5158 asmlinkage void __sched preempt_schedule(void)
5160 struct thread_info *ti = current_thread_info();
5163 * If there is a non-zero preempt_count or interrupts are disabled,
5164 * we do not want to preempt the current task. Just return..
5166 if (likely(ti->preempt_count || irqs_disabled()))
5170 add_preempt_count(PREEMPT_ACTIVE);
5172 sub_preempt_count(PREEMPT_ACTIVE);
5175 * Check again in case we missed a preemption opportunity
5176 * between schedule and now.
5179 } while (need_resched());
5181 EXPORT_SYMBOL(preempt_schedule);
5184 * this is the entry point to schedule() from kernel preemption
5185 * off of irq context.
5186 * Note, that this is called and return with irqs disabled. This will
5187 * protect us against recursive calling from irq.
5189 asmlinkage void __sched preempt_schedule_irq(void)
5191 struct thread_info *ti = current_thread_info();
5193 /* Catch callers which need to be fixed */
5194 BUG_ON(ti->preempt_count || !irqs_disabled());
5197 add_preempt_count(PREEMPT_ACTIVE);
5200 local_irq_disable();
5201 sub_preempt_count(PREEMPT_ACTIVE);
5204 * Check again in case we missed a preemption opportunity
5205 * between schedule and now.
5208 } while (need_resched());
5211 #endif /* CONFIG_PREEMPT */
5213 int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
5216 return try_to_wake_up(curr->private, mode, sync);
5218 EXPORT_SYMBOL(default_wake_function);
5221 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
5222 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
5223 * number) then we wake all the non-exclusive tasks and one exclusive task.
5225 * There are circumstances in which we can try to wake a task which has already
5226 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
5227 * zero in this (rare) case, and we handle it by continuing to scan the queue.
5229 void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
5230 int nr_exclusive, int sync, void *key)
5232 wait_queue_t *curr, *next;
5234 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
5235 unsigned flags = curr->flags;
5237 if (curr->func(curr, mode, sync, key) &&
5238 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
5244 * __wake_up - wake up threads blocked on a waitqueue.
5246 * @mode: which threads
5247 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5248 * @key: is directly passed to the wakeup function
5250 void __wake_up(wait_queue_head_t *q, unsigned int mode,
5251 int nr_exclusive, void *key)
5253 unsigned long flags;
5255 spin_lock_irqsave(&q->lock, flags);
5256 __wake_up_common(q, mode, nr_exclusive, 0, key);
5257 spin_unlock_irqrestore(&q->lock, flags);
5259 EXPORT_SYMBOL(__wake_up);
5262 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
5264 void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
5266 __wake_up_common(q, mode, 1, 0, NULL);
5269 void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
5271 __wake_up_common(q, mode, 1, 0, key);
5275 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
5277 * @mode: which threads
5278 * @nr_exclusive: how many wake-one or wake-many threads to wake up
5279 * @key: opaque value to be passed to wakeup targets
5281 * The sync wakeup differs that the waker knows that it will schedule
5282 * away soon, so while the target thread will be woken up, it will not
5283 * be migrated to another CPU - ie. the two threads are 'synchronized'
5284 * with each other. This can prevent needless bouncing between CPUs.
5286 * On UP it can prevent extra preemption.
5288 void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
5289 int nr_exclusive, void *key)
5291 unsigned long flags;
5297 if (unlikely(!nr_exclusive))
5300 spin_lock_irqsave(&q->lock, flags);
5301 __wake_up_common(q, mode, nr_exclusive, sync, key);
5302 spin_unlock_irqrestore(&q->lock, flags);
5304 EXPORT_SYMBOL_GPL(__wake_up_sync_key);
5307 * __wake_up_sync - see __wake_up_sync_key()
5309 void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
5311 __wake_up_sync_key(q, mode, nr_exclusive, NULL);
5313 EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
5316 * complete: - signals a single thread waiting on this completion
5317 * @x: holds the state of this particular completion
5319 * This will wake up a single thread waiting on this completion. Threads will be
5320 * awakened in the same order in which they were queued.
5322 * See also complete_all(), wait_for_completion() and related routines.
5324 void complete(struct completion *x)
5326 unsigned long flags;
5328 spin_lock_irqsave(&x->wait.lock, flags);
5330 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
5331 spin_unlock_irqrestore(&x->wait.lock, flags);
5333 EXPORT_SYMBOL(complete);
5336 * complete_all: - signals all threads waiting on this completion
5337 * @x: holds the state of this particular completion
5339 * This will wake up all threads waiting on this particular completion event.
5341 void complete_all(struct completion *x)
5343 unsigned long flags;
5345 spin_lock_irqsave(&x->wait.lock, flags);
5346 x->done += UINT_MAX/2;
5347 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
5348 spin_unlock_irqrestore(&x->wait.lock, flags);
5350 EXPORT_SYMBOL(complete_all);
5352 static inline long __sched
5353 do_wait_for_common(struct completion *x, long timeout, int state)
5356 DECLARE_WAITQUEUE(wait, current);
5358 wait.flags |= WQ_FLAG_EXCLUSIVE;
5359 __add_wait_queue_tail(&x->wait, &wait);
5361 if (signal_pending_state(state, current)) {
5362 timeout = -ERESTARTSYS;
5365 __set_current_state(state);
5366 spin_unlock_irq(&x->wait.lock);
5367 timeout = schedule_timeout(timeout);
5368 spin_lock_irq(&x->wait.lock);
5369 } while (!x->done && timeout);
5370 __remove_wait_queue(&x->wait, &wait);
5375 return timeout ?: 1;
5379 wait_for_common(struct completion *x, long timeout, int state)
5383 spin_lock_irq(&x->wait.lock);
5384 timeout = do_wait_for_common(x, timeout, state);
5385 spin_unlock_irq(&x->wait.lock);
5390 * wait_for_completion: - waits for completion of a task
5391 * @x: holds the state of this particular completion
5393 * This waits to be signaled for completion of a specific task. It is NOT
5394 * interruptible and there is no timeout.
5396 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
5397 * and interrupt capability. Also see complete().
5399 void __sched wait_for_completion(struct completion *x)
5401 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
5403 EXPORT_SYMBOL(wait_for_completion);
5406 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
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. The timeout is in jiffies. It is not
5414 unsigned long __sched
5415 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
5417 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
5419 EXPORT_SYMBOL(wait_for_completion_timeout);
5422 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
5423 * @x: holds the state of this particular completion
5425 * This waits for completion of a specific task to be signaled. It is
5428 int __sched wait_for_completion_interruptible(struct completion *x)
5430 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
5431 if (t == -ERESTARTSYS)
5435 EXPORT_SYMBOL(wait_for_completion_interruptible);
5438 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
5439 * @x: holds the state of this particular completion
5440 * @timeout: timeout value in jiffies
5442 * This waits for either a completion of a specific task to be signaled or for a
5443 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
5445 unsigned long __sched
5446 wait_for_completion_interruptible_timeout(struct completion *x,
5447 unsigned long timeout)
5449 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
5451 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
5454 * wait_for_completion_killable: - waits for completion of a task (killable)
5455 * @x: holds the state of this particular completion
5457 * This waits to be signaled for completion of a specific task. It can be
5458 * interrupted by a kill signal.
5460 int __sched wait_for_completion_killable(struct completion *x)
5462 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
5463 if (t == -ERESTARTSYS)
5467 EXPORT_SYMBOL(wait_for_completion_killable);
5470 * try_wait_for_completion - try to decrement a completion without blocking
5471 * @x: completion structure
5473 * Returns: 0 if a decrement cannot be done without blocking
5474 * 1 if a decrement succeeded.
5476 * If a completion is being used as a counting completion,
5477 * attempt to decrement the counter without blocking. This
5478 * enables us to avoid waiting if the resource the completion
5479 * is protecting is not available.
5481 bool try_wait_for_completion(struct completion *x)
5485 spin_lock_irq(&x->wait.lock);
5490 spin_unlock_irq(&x->wait.lock);
5493 EXPORT_SYMBOL(try_wait_for_completion);
5496 * completion_done - Test to see if a completion has any waiters
5497 * @x: completion structure
5499 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5500 * 1 if there are no waiters.
5503 bool completion_done(struct completion *x)
5507 spin_lock_irq(&x->wait.lock);
5510 spin_unlock_irq(&x->wait.lock);
5513 EXPORT_SYMBOL(completion_done);
5516 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
5518 unsigned long flags;
5521 init_waitqueue_entry(&wait, current);
5523 __set_current_state(state);
5525 spin_lock_irqsave(&q->lock, flags);
5526 __add_wait_queue(q, &wait);
5527 spin_unlock(&q->lock);
5528 timeout = schedule_timeout(timeout);
5529 spin_lock_irq(&q->lock);
5530 __remove_wait_queue(q, &wait);
5531 spin_unlock_irqrestore(&q->lock, flags);
5536 void __sched interruptible_sleep_on(wait_queue_head_t *q)
5538 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
5540 EXPORT_SYMBOL(interruptible_sleep_on);
5543 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
5545 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
5547 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
5549 void __sched sleep_on(wait_queue_head_t *q)
5551 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
5553 EXPORT_SYMBOL(sleep_on);
5555 long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
5557 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
5559 EXPORT_SYMBOL(sleep_on_timeout);
5561 #ifdef CONFIG_RT_MUTEXES
5564 * rt_mutex_setprio - set the current priority of a task
5566 * @prio: prio value (kernel-internal form)
5568 * This function changes the 'effective' priority of a task. It does
5569 * not touch ->normal_prio like __setscheduler().
5571 * Used by the rt_mutex code to implement priority inheritance logic.
5573 void rt_mutex_setprio(struct task_struct *p, int prio)
5575 unsigned long flags;
5576 int oldprio, on_rq, running;
5578 const struct sched_class *prev_class = p->sched_class;
5580 BUG_ON(prio < 0 || prio > MAX_PRIO);
5582 rq = task_rq_lock(p, &flags);
5583 update_rq_clock(rq);
5586 on_rq = p->se.on_rq;
5587 running = task_current(rq, p);
5589 dequeue_task(rq, p, 0);
5591 p->sched_class->put_prev_task(rq, p);
5594 p->sched_class = &rt_sched_class;
5596 p->sched_class = &fair_sched_class;
5601 p->sched_class->set_curr_task(rq);
5603 enqueue_task(rq, p, 0);
5605 check_class_changed(rq, p, prev_class, oldprio, running);
5607 task_rq_unlock(rq, &flags);
5612 void set_user_nice(struct task_struct *p, long nice)
5614 int old_prio, delta, on_rq;
5615 unsigned long flags;
5618 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
5621 * We have to be careful, if called from sys_setpriority(),
5622 * the task might be in the middle of scheduling on another CPU.
5624 rq = task_rq_lock(p, &flags);
5625 update_rq_clock(rq);
5627 * The RT priorities are set via sched_setscheduler(), but we still
5628 * allow the 'normal' nice value to be set - but as expected
5629 * it wont have any effect on scheduling until the task is
5630 * SCHED_FIFO/SCHED_RR:
5632 if (task_has_rt_policy(p)) {
5633 p->static_prio = NICE_TO_PRIO(nice);
5636 on_rq = p->se.on_rq;
5638 dequeue_task(rq, p, 0);
5640 p->static_prio = NICE_TO_PRIO(nice);
5643 p->prio = effective_prio(p);
5644 delta = p->prio - old_prio;
5647 enqueue_task(rq, p, 0);
5649 * If the task increased its priority or is running and
5650 * lowered its priority, then reschedule its CPU:
5652 if (delta < 0 || (delta > 0 && task_running(rq, p)))
5653 resched_task(rq->curr);
5656 task_rq_unlock(rq, &flags);
5658 EXPORT_SYMBOL(set_user_nice);
5661 * can_nice - check if a task can reduce its nice value
5665 int can_nice(const struct task_struct *p, const int nice)
5667 /* convert nice value [19,-20] to rlimit style value [1,40] */
5668 int nice_rlim = 20 - nice;
5670 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
5671 capable(CAP_SYS_NICE));
5674 #ifdef __ARCH_WANT_SYS_NICE
5677 * sys_nice - change the priority of the current process.
5678 * @increment: priority increment
5680 * sys_setpriority is a more generic, but much slower function that
5681 * does similar things.
5683 SYSCALL_DEFINE1(nice, int, increment)
5688 * Setpriority might change our priority at the same moment.
5689 * We don't have to worry. Conceptually one call occurs first
5690 * and we have a single winner.
5692 if (increment < -40)
5697 nice = TASK_NICE(current) + increment;
5703 if (increment < 0 && !can_nice(current, nice))
5706 retval = security_task_setnice(current, nice);
5710 set_user_nice(current, nice);
5717 * task_prio - return the priority value of a given task.
5718 * @p: the task in question.
5720 * This is the priority value as seen by users in /proc.
5721 * RT tasks are offset by -200. Normal tasks are centered
5722 * around 0, value goes from -16 to +15.
5724 int task_prio(const struct task_struct *p)
5726 return p->prio - MAX_RT_PRIO;
5730 * task_nice - return the nice value of a given task.
5731 * @p: the task in question.
5733 int task_nice(const struct task_struct *p)
5735 return TASK_NICE(p);
5737 EXPORT_SYMBOL(task_nice);
5740 * idle_cpu - is a given cpu idle currently?
5741 * @cpu: the processor in question.
5743 int idle_cpu(int cpu)
5745 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
5749 * idle_task - return the idle task for a given cpu.
5750 * @cpu: the processor in question.
5752 struct task_struct *idle_task(int cpu)
5754 return cpu_rq(cpu)->idle;
5758 * find_process_by_pid - find a process with a matching PID value.
5759 * @pid: the pid in question.
5761 static struct task_struct *find_process_by_pid(pid_t pid)
5763 return pid ? find_task_by_vpid(pid) : current;
5766 /* Actually do priority change: must hold rq lock. */
5768 __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
5770 BUG_ON(p->se.on_rq);
5773 switch (p->policy) {
5777 p->sched_class = &fair_sched_class;
5781 p->sched_class = &rt_sched_class;
5785 p->rt_priority = prio;
5786 p->normal_prio = normal_prio(p);
5787 /* we are holding p->pi_lock already */
5788 p->prio = rt_mutex_getprio(p);
5793 * check the target process has a UID that matches the current process's
5795 static bool check_same_owner(struct task_struct *p)
5797 const struct cred *cred = current_cred(), *pcred;
5801 pcred = __task_cred(p);
5802 match = (cred->euid == pcred->euid ||
5803 cred->euid == pcred->uid);
5808 static int __sched_setscheduler(struct task_struct *p, int policy,
5809 struct sched_param *param, bool user)
5811 int retval, oldprio, oldpolicy = -1, on_rq, running;
5812 unsigned long flags;
5813 const struct sched_class *prev_class = p->sched_class;
5816 /* may grab non-irq protected spin_locks */
5817 BUG_ON(in_interrupt());
5819 /* double check policy once rq lock held */
5821 policy = oldpolicy = p->policy;
5822 else if (policy != SCHED_FIFO && policy != SCHED_RR &&
5823 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
5824 policy != SCHED_IDLE)
5827 * Valid priorities for SCHED_FIFO and SCHED_RR are
5828 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5829 * SCHED_BATCH and SCHED_IDLE is 0.
5831 if (param->sched_priority < 0 ||
5832 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
5833 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
5835 if (rt_policy(policy) != (param->sched_priority != 0))
5839 * Allow unprivileged RT tasks to decrease priority:
5841 if (user && !capable(CAP_SYS_NICE)) {
5842 if (rt_policy(policy)) {
5843 unsigned long rlim_rtprio;
5845 if (!lock_task_sighand(p, &flags))
5847 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
5848 unlock_task_sighand(p, &flags);
5850 /* can't set/change the rt policy */
5851 if (policy != p->policy && !rlim_rtprio)
5854 /* can't increase priority */
5855 if (param->sched_priority > p->rt_priority &&
5856 param->sched_priority > rlim_rtprio)
5860 * Like positive nice levels, dont allow tasks to
5861 * move out of SCHED_IDLE either:
5863 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
5866 /* can't change other user's priorities */
5867 if (!check_same_owner(p))
5872 #ifdef CONFIG_RT_GROUP_SCHED
5874 * Do not allow realtime tasks into groups that have no runtime
5877 if (rt_bandwidth_enabled() && rt_policy(policy) &&
5878 task_group(p)->rt_bandwidth.rt_runtime == 0)
5882 retval = security_task_setscheduler(p, policy, param);
5888 * make sure no PI-waiters arrive (or leave) while we are
5889 * changing the priority of the task:
5891 spin_lock_irqsave(&p->pi_lock, flags);
5893 * To be able to change p->policy safely, the apropriate
5894 * runqueue lock must be held.
5896 rq = __task_rq_lock(p);
5897 /* recheck policy now with rq lock held */
5898 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
5899 policy = oldpolicy = -1;
5900 __task_rq_unlock(rq);
5901 spin_unlock_irqrestore(&p->pi_lock, flags);
5904 update_rq_clock(rq);
5905 on_rq = p->se.on_rq;
5906 running = task_current(rq, p);
5908 deactivate_task(rq, p, 0);
5910 p->sched_class->put_prev_task(rq, p);
5913 __setscheduler(rq, p, policy, param->sched_priority);
5916 p->sched_class->set_curr_task(rq);
5918 activate_task(rq, p, 0);
5920 check_class_changed(rq, p, prev_class, oldprio, running);
5922 __task_rq_unlock(rq);
5923 spin_unlock_irqrestore(&p->pi_lock, flags);
5925 rt_mutex_adjust_pi(p);
5931 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5932 * @p: the task in question.
5933 * @policy: new policy.
5934 * @param: structure containing the new RT priority.
5936 * NOTE that the task may be already dead.
5938 int sched_setscheduler(struct task_struct *p, int policy,
5939 struct sched_param *param)
5941 return __sched_setscheduler(p, policy, param, true);
5943 EXPORT_SYMBOL_GPL(sched_setscheduler);
5946 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5947 * @p: the task in question.
5948 * @policy: new policy.
5949 * @param: structure containing the new RT priority.
5951 * Just like sched_setscheduler, only don't bother checking if the
5952 * current context has permission. For example, this is needed in
5953 * stop_machine(): we create temporary high priority worker threads,
5954 * but our caller might not have that capability.
5956 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
5957 struct sched_param *param)
5959 return __sched_setscheduler(p, policy, param, false);
5963 do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
5965 struct sched_param lparam;
5966 struct task_struct *p;
5969 if (!param || pid < 0)
5971 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
5976 p = find_process_by_pid(pid);
5978 retval = sched_setscheduler(p, policy, &lparam);
5985 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5986 * @pid: the pid in question.
5987 * @policy: new policy.
5988 * @param: structure containing the new RT priority.
5990 SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
5991 struct sched_param __user *, param)
5993 /* negative values for policy are not valid */
5997 return do_sched_setscheduler(pid, policy, param);
6001 * sys_sched_setparam - set/change the RT priority of a thread
6002 * @pid: the pid in question.
6003 * @param: structure containing the new RT priority.
6005 SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
6007 return do_sched_setscheduler(pid, -1, param);
6011 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
6012 * @pid: the pid in question.
6014 SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
6016 struct task_struct *p;
6023 read_lock(&tasklist_lock);
6024 p = find_process_by_pid(pid);
6026 retval = security_task_getscheduler(p);
6030 read_unlock(&tasklist_lock);
6035 * sys_sched_getscheduler - get the RT priority of a thread
6036 * @pid: the pid in question.
6037 * @param: structure containing the RT priority.
6039 SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
6041 struct sched_param lp;
6042 struct task_struct *p;
6045 if (!param || pid < 0)
6048 read_lock(&tasklist_lock);
6049 p = find_process_by_pid(pid);
6054 retval = security_task_getscheduler(p);
6058 lp.sched_priority = p->rt_priority;
6059 read_unlock(&tasklist_lock);
6062 * This one might sleep, we cannot do it with a spinlock held ...
6064 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
6069 read_unlock(&tasklist_lock);
6073 long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
6075 cpumask_var_t cpus_allowed, new_mask;
6076 struct task_struct *p;
6080 read_lock(&tasklist_lock);
6082 p = find_process_by_pid(pid);
6084 read_unlock(&tasklist_lock);
6090 * It is not safe to call set_cpus_allowed with the
6091 * tasklist_lock held. We will bump the task_struct's
6092 * usage count and then drop tasklist_lock.
6095 read_unlock(&tasklist_lock);
6097 if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
6101 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
6103 goto out_free_cpus_allowed;
6106 if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
6109 retval = security_task_setscheduler(p, 0, NULL);
6113 cpuset_cpus_allowed(p, cpus_allowed);
6114 cpumask_and(new_mask, in_mask, cpus_allowed);
6116 retval = set_cpus_allowed_ptr(p, new_mask);
6119 cpuset_cpus_allowed(p, cpus_allowed);
6120 if (!cpumask_subset(new_mask, cpus_allowed)) {
6122 * We must have raced with a concurrent cpuset
6123 * update. Just reset the cpus_allowed to the
6124 * cpuset's cpus_allowed
6126 cpumask_copy(new_mask, cpus_allowed);
6131 free_cpumask_var(new_mask);
6132 out_free_cpus_allowed:
6133 free_cpumask_var(cpus_allowed);
6140 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
6141 struct cpumask *new_mask)
6143 if (len < cpumask_size())
6144 cpumask_clear(new_mask);
6145 else if (len > cpumask_size())
6146 len = cpumask_size();
6148 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
6152 * sys_sched_setaffinity - set the cpu affinity of a process
6153 * @pid: pid of the process
6154 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6155 * @user_mask_ptr: user-space pointer to the new cpu mask
6157 SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
6158 unsigned long __user *, user_mask_ptr)
6160 cpumask_var_t new_mask;
6163 if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
6166 retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
6168 retval = sched_setaffinity(pid, new_mask);
6169 free_cpumask_var(new_mask);
6173 long sched_getaffinity(pid_t pid, struct cpumask *mask)
6175 struct task_struct *p;
6179 read_lock(&tasklist_lock);
6182 p = find_process_by_pid(pid);
6186 retval = security_task_getscheduler(p);
6190 cpumask_and(mask, &p->cpus_allowed, cpu_online_mask);
6193 read_unlock(&tasklist_lock);
6200 * sys_sched_getaffinity - get the cpu affinity of a process
6201 * @pid: pid of the process
6202 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
6203 * @user_mask_ptr: user-space pointer to hold the current cpu mask
6205 SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
6206 unsigned long __user *, user_mask_ptr)
6211 if (len < cpumask_size())
6214 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
6217 ret = sched_getaffinity(pid, mask);
6219 if (copy_to_user(user_mask_ptr, mask, cpumask_size()))
6222 ret = cpumask_size();
6224 free_cpumask_var(mask);
6230 * sys_sched_yield - yield the current processor to other threads.
6232 * This function yields the current CPU to other tasks. If there are no
6233 * other threads running on this CPU then this function will return.
6235 SYSCALL_DEFINE0(sched_yield)
6237 struct rq *rq = this_rq_lock();
6239 schedstat_inc(rq, yld_count);
6240 current->sched_class->yield_task(rq);
6243 * Since we are going to call schedule() anyway, there's
6244 * no need to preempt or enable interrupts:
6246 __release(rq->lock);
6247 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
6248 _raw_spin_unlock(&rq->lock);
6249 preempt_enable_no_resched();
6256 static void __cond_resched(void)
6258 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
6259 __might_sleep(__FILE__, __LINE__);
6262 * The BKS might be reacquired before we have dropped
6263 * PREEMPT_ACTIVE, which could trigger a second
6264 * cond_resched() call.
6267 add_preempt_count(PREEMPT_ACTIVE);
6269 sub_preempt_count(PREEMPT_ACTIVE);
6270 } while (need_resched());
6273 int __sched _cond_resched(void)
6275 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
6276 system_state == SYSTEM_RUNNING) {
6282 EXPORT_SYMBOL(_cond_resched);
6285 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
6286 * call schedule, and on return reacquire the lock.
6288 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
6289 * operations here to prevent schedule() from being called twice (once via
6290 * spin_unlock(), once by hand).
6292 int cond_resched_lock(spinlock_t *lock)
6294 int resched = need_resched() && system_state == SYSTEM_RUNNING;
6297 if (spin_needbreak(lock) || resched) {
6299 if (resched && need_resched())
6308 EXPORT_SYMBOL(cond_resched_lock);
6310 int __sched cond_resched_softirq(void)
6312 BUG_ON(!in_softirq());
6314 if (need_resched() && system_state == SYSTEM_RUNNING) {
6322 EXPORT_SYMBOL(cond_resched_softirq);
6325 * yield - yield the current processor to other threads.
6327 * This is a shortcut for kernel-space yielding - it marks the
6328 * thread runnable and calls sys_sched_yield().
6330 void __sched yield(void)
6332 set_current_state(TASK_RUNNING);
6335 EXPORT_SYMBOL(yield);
6338 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
6339 * that process accounting knows that this is a task in IO wait state.
6341 * But don't do that if it is a deliberate, throttling IO wait (this task
6342 * has set its backing_dev_info: the queue against which it should throttle)
6344 void __sched io_schedule(void)
6346 struct rq *rq = &__raw_get_cpu_var(runqueues);
6348 delayacct_blkio_start();
6349 atomic_inc(&rq->nr_iowait);
6351 atomic_dec(&rq->nr_iowait);
6352 delayacct_blkio_end();
6354 EXPORT_SYMBOL(io_schedule);
6356 long __sched io_schedule_timeout(long timeout)
6358 struct rq *rq = &__raw_get_cpu_var(runqueues);
6361 delayacct_blkio_start();
6362 atomic_inc(&rq->nr_iowait);
6363 ret = schedule_timeout(timeout);
6364 atomic_dec(&rq->nr_iowait);
6365 delayacct_blkio_end();
6370 * sys_sched_get_priority_max - return maximum RT priority.
6371 * @policy: scheduling class.
6373 * this syscall returns the maximum rt_priority that can be used
6374 * by a given scheduling class.
6376 SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
6383 ret = MAX_USER_RT_PRIO-1;
6395 * sys_sched_get_priority_min - return minimum RT priority.
6396 * @policy: scheduling class.
6398 * this syscall returns the minimum rt_priority that can be used
6399 * by a given scheduling class.
6401 SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
6419 * sys_sched_rr_get_interval - return the default timeslice of a process.
6420 * @pid: pid of the process.
6421 * @interval: userspace pointer to the timeslice value.
6423 * this syscall writes the default timeslice value of a given process
6424 * into the user-space timespec buffer. A value of '0' means infinity.
6426 SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
6427 struct timespec __user *, interval)
6429 struct task_struct *p;
6430 unsigned int time_slice;
6438 read_lock(&tasklist_lock);
6439 p = find_process_by_pid(pid);
6443 retval = security_task_getscheduler(p);
6448 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6449 * tasks that are on an otherwise idle runqueue:
6452 if (p->policy == SCHED_RR) {
6453 time_slice = DEF_TIMESLICE;
6454 } else if (p->policy != SCHED_FIFO) {
6455 struct sched_entity *se = &p->se;
6456 unsigned long flags;
6459 rq = task_rq_lock(p, &flags);
6460 if (rq->cfs.load.weight)
6461 time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
6462 task_rq_unlock(rq, &flags);
6464 read_unlock(&tasklist_lock);
6465 jiffies_to_timespec(time_slice, &t);
6466 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
6470 read_unlock(&tasklist_lock);
6474 static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
6476 void sched_show_task(struct task_struct *p)
6478 unsigned long free = 0;
6481 state = p->state ? __ffs(p->state) + 1 : 0;
6482 printk(KERN_INFO "%-13.13s %c", p->comm,
6483 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
6484 #if BITS_PER_LONG == 32
6485 if (state == TASK_RUNNING)
6486 printk(KERN_CONT " running ");
6488 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
6490 if (state == TASK_RUNNING)
6491 printk(KERN_CONT " running task ");
6493 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
6495 #ifdef CONFIG_DEBUG_STACK_USAGE
6496 free = stack_not_used(p);
6498 printk(KERN_CONT "%5lu %5d %6d\n", free,
6499 task_pid_nr(p), task_pid_nr(p->real_parent));
6501 show_stack(p, NULL);
6504 void show_state_filter(unsigned long state_filter)
6506 struct task_struct *g, *p;
6508 #if BITS_PER_LONG == 32
6510 " task PC stack pid father\n");
6513 " task PC stack pid father\n");
6515 read_lock(&tasklist_lock);
6516 do_each_thread(g, p) {
6518 * reset the NMI-timeout, listing all files on a slow
6519 * console might take alot of time:
6521 touch_nmi_watchdog();
6522 if (!state_filter || (p->state & state_filter))
6524 } while_each_thread(g, p);
6526 touch_all_softlockup_watchdogs();
6528 #ifdef CONFIG_SCHED_DEBUG
6529 sysrq_sched_debug_show();
6531 read_unlock(&tasklist_lock);
6533 * Only show locks if all tasks are dumped:
6535 if (state_filter == -1)
6536 debug_show_all_locks();
6539 void __cpuinit init_idle_bootup_task(struct task_struct *idle)
6541 idle->sched_class = &idle_sched_class;
6545 * init_idle - set up an idle thread for a given CPU
6546 * @idle: task in question
6547 * @cpu: cpu the idle task belongs to
6549 * NOTE: this function does not set the idle thread's NEED_RESCHED
6550 * flag, to make booting more robust.
6552 void __cpuinit init_idle(struct task_struct *idle, int cpu)
6554 struct rq *rq = cpu_rq(cpu);
6555 unsigned long flags;
6557 spin_lock_irqsave(&rq->lock, flags);
6560 idle->se.exec_start = sched_clock();
6562 idle->prio = idle->normal_prio = MAX_PRIO;
6563 cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
6564 __set_task_cpu(idle, cpu);
6566 rq->curr = rq->idle = idle;
6567 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6570 spin_unlock_irqrestore(&rq->lock, flags);
6572 /* Set the preempt count _outside_ the spinlocks! */
6573 #if defined(CONFIG_PREEMPT)
6574 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
6576 task_thread_info(idle)->preempt_count = 0;
6579 * The idle tasks have their own, simple scheduling class:
6581 idle->sched_class = &idle_sched_class;
6582 ftrace_graph_init_task(idle);
6586 * In a system that switches off the HZ timer nohz_cpu_mask
6587 * indicates which cpus entered this state. This is used
6588 * in the rcu update to wait only for active cpus. For system
6589 * which do not switch off the HZ timer nohz_cpu_mask should
6590 * always be CPU_BITS_NONE.
6592 cpumask_var_t nohz_cpu_mask;
6595 * Increase the granularity value when there are more CPUs,
6596 * because with more CPUs the 'effective latency' as visible
6597 * to users decreases. But the relationship is not linear,
6598 * so pick a second-best guess by going with the log2 of the
6601 * This idea comes from the SD scheduler of Con Kolivas:
6603 static inline void sched_init_granularity(void)
6605 unsigned int factor = 1 + ilog2(num_online_cpus());
6606 const unsigned long limit = 200000000;
6608 sysctl_sched_min_granularity *= factor;
6609 if (sysctl_sched_min_granularity > limit)
6610 sysctl_sched_min_granularity = limit;
6612 sysctl_sched_latency *= factor;
6613 if (sysctl_sched_latency > limit)
6614 sysctl_sched_latency = limit;
6616 sysctl_sched_wakeup_granularity *= factor;
6618 sysctl_sched_shares_ratelimit *= factor;
6623 * This is how migration works:
6625 * 1) we queue a struct migration_req structure in the source CPU's
6626 * runqueue and wake up that CPU's migration thread.
6627 * 2) we down() the locked semaphore => thread blocks.
6628 * 3) migration thread wakes up (implicitly it forces the migrated
6629 * thread off the CPU)
6630 * 4) it gets the migration request and checks whether the migrated
6631 * task is still in the wrong runqueue.
6632 * 5) if it's in the wrong runqueue then the migration thread removes
6633 * it and puts it into the right queue.
6634 * 6) migration thread up()s the semaphore.
6635 * 7) we wake up and the migration is done.
6639 * Change a given task's CPU affinity. Migrate the thread to a
6640 * proper CPU and schedule it away if the CPU it's executing on
6641 * is removed from the allowed bitmask.
6643 * NOTE: the caller must have a valid reference to the task, the
6644 * task must not exit() & deallocate itself prematurely. The
6645 * call is not atomic; no spinlocks may be held.
6647 int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
6649 struct migration_req req;
6650 unsigned long flags;
6654 rq = task_rq_lock(p, &flags);
6655 if (!cpumask_intersects(new_mask, cpu_online_mask)) {
6660 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
6661 !cpumask_equal(&p->cpus_allowed, new_mask))) {
6666 if (p->sched_class->set_cpus_allowed)
6667 p->sched_class->set_cpus_allowed(p, new_mask);
6669 cpumask_copy(&p->cpus_allowed, new_mask);
6670 p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
6673 /* Can the task run on the task's current CPU? If so, we're done */
6674 if (cpumask_test_cpu(task_cpu(p), new_mask))
6677 if (migrate_task(p, cpumask_any_and(cpu_online_mask, new_mask), &req)) {
6678 /* Need help from migration thread: drop lock and wait. */
6679 task_rq_unlock(rq, &flags);
6680 wake_up_process(rq->migration_thread);
6681 wait_for_completion(&req.done);
6682 tlb_migrate_finish(p->mm);
6686 task_rq_unlock(rq, &flags);
6690 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
6693 * Move (not current) task off this cpu, onto dest cpu. We're doing
6694 * this because either it can't run here any more (set_cpus_allowed()
6695 * away from this CPU, or CPU going down), or because we're
6696 * attempting to rebalance this task on exec (sched_exec).
6698 * So we race with normal scheduler movements, but that's OK, as long
6699 * as the task is no longer on this CPU.
6701 * Returns non-zero if task was successfully migrated.
6703 static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
6705 struct rq *rq_dest, *rq_src;
6708 if (unlikely(!cpu_active(dest_cpu)))
6711 rq_src = cpu_rq(src_cpu);
6712 rq_dest = cpu_rq(dest_cpu);
6714 double_rq_lock(rq_src, rq_dest);
6715 /* Already moved. */
6716 if (task_cpu(p) != src_cpu)
6718 /* Affinity changed (again). */
6719 if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
6722 on_rq = p->se.on_rq;
6724 deactivate_task(rq_src, p, 0);
6726 set_task_cpu(p, dest_cpu);
6728 activate_task(rq_dest, p, 0);
6729 check_preempt_curr(rq_dest, p, 0);
6734 double_rq_unlock(rq_src, rq_dest);
6739 * migration_thread - this is a highprio system thread that performs
6740 * thread migration by bumping thread off CPU then 'pushing' onto
6743 static int migration_thread(void *data)
6745 int cpu = (long)data;
6749 BUG_ON(rq->migration_thread != current);
6751 set_current_state(TASK_INTERRUPTIBLE);
6752 while (!kthread_should_stop()) {
6753 struct migration_req *req;
6754 struct list_head *head;
6756 spin_lock_irq(&rq->lock);
6758 if (cpu_is_offline(cpu)) {
6759 spin_unlock_irq(&rq->lock);
6763 if (rq->active_balance) {
6764 active_load_balance(rq, cpu);
6765 rq->active_balance = 0;
6768 head = &rq->migration_queue;
6770 if (list_empty(head)) {
6771 spin_unlock_irq(&rq->lock);
6773 set_current_state(TASK_INTERRUPTIBLE);
6776 req = list_entry(head->next, struct migration_req, list);
6777 list_del_init(head->next);
6779 spin_unlock(&rq->lock);
6780 __migrate_task(req->task, cpu, req->dest_cpu);
6783 complete(&req->done);
6785 __set_current_state(TASK_RUNNING);
6789 /* Wait for kthread_stop */
6790 set_current_state(TASK_INTERRUPTIBLE);
6791 while (!kthread_should_stop()) {
6793 set_current_state(TASK_INTERRUPTIBLE);
6795 __set_current_state(TASK_RUNNING);
6799 #ifdef CONFIG_HOTPLUG_CPU
6801 static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
6805 local_irq_disable();
6806 ret = __migrate_task(p, src_cpu, dest_cpu);
6812 * Figure out where task on dead CPU should go, use force if necessary.
6814 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
6817 const struct cpumask *nodemask = cpumask_of_node(cpu_to_node(dead_cpu));
6820 /* Look for allowed, online CPU in same node. */
6821 for_each_cpu_and(dest_cpu, nodemask, cpu_online_mask)
6822 if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))
6825 /* Any allowed, online CPU? */
6826 dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_online_mask);
6827 if (dest_cpu < nr_cpu_ids)
6830 /* No more Mr. Nice Guy. */
6831 if (dest_cpu >= nr_cpu_ids) {
6832 cpuset_cpus_allowed_locked(p, &p->cpus_allowed);
6833 dest_cpu = cpumask_any_and(cpu_online_mask, &p->cpus_allowed);
6836 * Don't tell them about moving exiting tasks or
6837 * kernel threads (both mm NULL), since they never
6840 if (p->mm && printk_ratelimit()) {
6841 printk(KERN_INFO "process %d (%s) no "
6842 "longer affine to cpu%d\n",
6843 task_pid_nr(p), p->comm, dead_cpu);
6848 /* It can have affinity changed while we were choosing. */
6849 if (unlikely(!__migrate_task_irq(p, dead_cpu, dest_cpu)))
6854 * While a dead CPU has no uninterruptible tasks queued at this point,
6855 * it might still have a nonzero ->nr_uninterruptible counter, because
6856 * for performance reasons the counter is not stricly tracking tasks to
6857 * their home CPUs. So we just add the counter to another CPU's counter,
6858 * to keep the global sum constant after CPU-down:
6860 static void migrate_nr_uninterruptible(struct rq *rq_src)
6862 struct rq *rq_dest = cpu_rq(cpumask_any(cpu_online_mask));
6863 unsigned long flags;
6865 local_irq_save(flags);
6866 double_rq_lock(rq_src, rq_dest);
6867 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
6868 rq_src->nr_uninterruptible = 0;
6869 double_rq_unlock(rq_src, rq_dest);
6870 local_irq_restore(flags);
6873 /* Run through task list and migrate tasks from the dead cpu. */
6874 static void migrate_live_tasks(int src_cpu)
6876 struct task_struct *p, *t;
6878 read_lock(&tasklist_lock);
6880 do_each_thread(t, p) {
6884 if (task_cpu(p) == src_cpu)
6885 move_task_off_dead_cpu(src_cpu, p);
6886 } while_each_thread(t, p);
6888 read_unlock(&tasklist_lock);
6892 * Schedules idle task to be the next runnable task on current CPU.
6893 * It does so by boosting its priority to highest possible.
6894 * Used by CPU offline code.
6896 void sched_idle_next(void)
6898 int this_cpu = smp_processor_id();
6899 struct rq *rq = cpu_rq(this_cpu);
6900 struct task_struct *p = rq->idle;
6901 unsigned long flags;
6903 /* cpu has to be offline */
6904 BUG_ON(cpu_online(this_cpu));
6907 * Strictly not necessary since rest of the CPUs are stopped by now
6908 * and interrupts disabled on the current cpu.
6910 spin_lock_irqsave(&rq->lock, flags);
6912 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
6914 update_rq_clock(rq);
6915 activate_task(rq, p, 0);
6917 spin_unlock_irqrestore(&rq->lock, flags);
6921 * Ensures that the idle task is using init_mm right before its cpu goes
6924 void idle_task_exit(void)
6926 struct mm_struct *mm = current->active_mm;
6928 BUG_ON(cpu_online(smp_processor_id()));
6931 switch_mm(mm, &init_mm, current);
6935 /* called under rq->lock with disabled interrupts */
6936 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
6938 struct rq *rq = cpu_rq(dead_cpu);
6940 /* Must be exiting, otherwise would be on tasklist. */
6941 BUG_ON(!p->exit_state);
6943 /* Cannot have done final schedule yet: would have vanished. */
6944 BUG_ON(p->state == TASK_DEAD);
6949 * Drop lock around migration; if someone else moves it,
6950 * that's OK. No task can be added to this CPU, so iteration is
6953 spin_unlock_irq(&rq->lock);
6954 move_task_off_dead_cpu(dead_cpu, p);
6955 spin_lock_irq(&rq->lock);
6960 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6961 static void migrate_dead_tasks(unsigned int dead_cpu)
6963 struct rq *rq = cpu_rq(dead_cpu);
6964 struct task_struct *next;
6967 if (!rq->nr_running)
6969 update_rq_clock(rq);
6970 next = pick_next_task(rq);
6973 next->sched_class->put_prev_task(rq, next);
6974 migrate_dead(dead_cpu, next);
6978 #endif /* CONFIG_HOTPLUG_CPU */
6980 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6982 static struct ctl_table sd_ctl_dir[] = {
6984 .procname = "sched_domain",
6990 static struct ctl_table sd_ctl_root[] = {
6992 .ctl_name = CTL_KERN,
6993 .procname = "kernel",
6995 .child = sd_ctl_dir,
7000 static struct ctl_table *sd_alloc_ctl_entry(int n)
7002 struct ctl_table *entry =
7003 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
7008 static void sd_free_ctl_entry(struct ctl_table **tablep)
7010 struct ctl_table *entry;
7013 * In the intermediate directories, both the child directory and
7014 * procname are dynamically allocated and could fail but the mode
7015 * will always be set. In the lowest directory the names are
7016 * static strings and all have proc handlers.
7018 for (entry = *tablep; entry->mode; entry++) {
7020 sd_free_ctl_entry(&entry->child);
7021 if (entry->proc_handler == NULL)
7022 kfree(entry->procname);
7030 set_table_entry(struct ctl_table *entry,
7031 const char *procname, void *data, int maxlen,
7032 mode_t mode, proc_handler *proc_handler)
7034 entry->procname = procname;
7036 entry->maxlen = maxlen;
7038 entry->proc_handler = proc_handler;
7041 static struct ctl_table *
7042 sd_alloc_ctl_domain_table(struct sched_domain *sd)
7044 struct ctl_table *table = sd_alloc_ctl_entry(13);
7049 set_table_entry(&table[0], "min_interval", &sd->min_interval,
7050 sizeof(long), 0644, proc_doulongvec_minmax);
7051 set_table_entry(&table[1], "max_interval", &sd->max_interval,
7052 sizeof(long), 0644, proc_doulongvec_minmax);
7053 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
7054 sizeof(int), 0644, proc_dointvec_minmax);
7055 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
7056 sizeof(int), 0644, proc_dointvec_minmax);
7057 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
7058 sizeof(int), 0644, proc_dointvec_minmax);
7059 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
7060 sizeof(int), 0644, proc_dointvec_minmax);
7061 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
7062 sizeof(int), 0644, proc_dointvec_minmax);
7063 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
7064 sizeof(int), 0644, proc_dointvec_minmax);
7065 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
7066 sizeof(int), 0644, proc_dointvec_minmax);
7067 set_table_entry(&table[9], "cache_nice_tries",
7068 &sd->cache_nice_tries,
7069 sizeof(int), 0644, proc_dointvec_minmax);
7070 set_table_entry(&table[10], "flags", &sd->flags,
7071 sizeof(int), 0644, proc_dointvec_minmax);
7072 set_table_entry(&table[11], "name", sd->name,
7073 CORENAME_MAX_SIZE, 0444, proc_dostring);
7074 /* &table[12] is terminator */
7079 static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
7081 struct ctl_table *entry, *table;
7082 struct sched_domain *sd;
7083 int domain_num = 0, i;
7086 for_each_domain(cpu, sd)
7088 entry = table = sd_alloc_ctl_entry(domain_num + 1);
7093 for_each_domain(cpu, sd) {
7094 snprintf(buf, 32, "domain%d", i);
7095 entry->procname = kstrdup(buf, GFP_KERNEL);
7097 entry->child = sd_alloc_ctl_domain_table(sd);
7104 static struct ctl_table_header *sd_sysctl_header;
7105 static void register_sched_domain_sysctl(void)
7107 int i, cpu_num = num_online_cpus();
7108 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
7111 WARN_ON(sd_ctl_dir[0].child);
7112 sd_ctl_dir[0].child = entry;
7117 for_each_online_cpu(i) {
7118 snprintf(buf, 32, "cpu%d", i);
7119 entry->procname = kstrdup(buf, GFP_KERNEL);
7121 entry->child = sd_alloc_ctl_cpu_table(i);
7125 WARN_ON(sd_sysctl_header);
7126 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
7129 /* may be called multiple times per register */
7130 static void unregister_sched_domain_sysctl(void)
7132 if (sd_sysctl_header)
7133 unregister_sysctl_table(sd_sysctl_header);
7134 sd_sysctl_header = NULL;
7135 if (sd_ctl_dir[0].child)
7136 sd_free_ctl_entry(&sd_ctl_dir[0].child);
7139 static void register_sched_domain_sysctl(void)
7142 static void unregister_sched_domain_sysctl(void)
7147 static void set_rq_online(struct rq *rq)
7150 const struct sched_class *class;
7152 cpumask_set_cpu(rq->cpu, rq->rd->online);
7155 for_each_class(class) {
7156 if (class->rq_online)
7157 class->rq_online(rq);
7162 static void set_rq_offline(struct rq *rq)
7165 const struct sched_class *class;
7167 for_each_class(class) {
7168 if (class->rq_offline)
7169 class->rq_offline(rq);
7172 cpumask_clear_cpu(rq->cpu, rq->rd->online);
7178 * migration_call - callback that gets triggered when a CPU is added.
7179 * Here we can start up the necessary migration thread for the new CPU.
7181 static int __cpuinit
7182 migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
7184 struct task_struct *p;
7185 int cpu = (long)hcpu;
7186 unsigned long flags;
7191 case CPU_UP_PREPARE:
7192 case CPU_UP_PREPARE_FROZEN:
7193 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
7196 kthread_bind(p, cpu);
7197 /* Must be high prio: stop_machine expects to yield to it. */
7198 rq = task_rq_lock(p, &flags);
7199 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
7200 task_rq_unlock(rq, &flags);
7201 cpu_rq(cpu)->migration_thread = p;
7205 case CPU_ONLINE_FROZEN:
7206 /* Strictly unnecessary, as first user will wake it. */
7207 wake_up_process(cpu_rq(cpu)->migration_thread);
7209 /* Update our root-domain */
7211 spin_lock_irqsave(&rq->lock, flags);
7213 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
7217 spin_unlock_irqrestore(&rq->lock, flags);
7220 #ifdef CONFIG_HOTPLUG_CPU
7221 case CPU_UP_CANCELED:
7222 case CPU_UP_CANCELED_FROZEN:
7223 if (!cpu_rq(cpu)->migration_thread)
7225 /* Unbind it from offline cpu so it can run. Fall thru. */
7226 kthread_bind(cpu_rq(cpu)->migration_thread,
7227 cpumask_any(cpu_online_mask));
7228 kthread_stop(cpu_rq(cpu)->migration_thread);
7229 cpu_rq(cpu)->migration_thread = NULL;
7233 case CPU_DEAD_FROZEN:
7234 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
7235 migrate_live_tasks(cpu);
7237 kthread_stop(rq->migration_thread);
7238 rq->migration_thread = NULL;
7239 /* Idle task back to normal (off runqueue, low prio) */
7240 spin_lock_irq(&rq->lock);
7241 update_rq_clock(rq);
7242 deactivate_task(rq, rq->idle, 0);
7243 rq->idle->static_prio = MAX_PRIO;
7244 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
7245 rq->idle->sched_class = &idle_sched_class;
7246 migrate_dead_tasks(cpu);
7247 spin_unlock_irq(&rq->lock);
7249 migrate_nr_uninterruptible(rq);
7250 BUG_ON(rq->nr_running != 0);
7253 * No need to migrate the tasks: it was best-effort if
7254 * they didn't take sched_hotcpu_mutex. Just wake up
7257 spin_lock_irq(&rq->lock);
7258 while (!list_empty(&rq->migration_queue)) {
7259 struct migration_req *req;
7261 req = list_entry(rq->migration_queue.next,
7262 struct migration_req, list);
7263 list_del_init(&req->list);
7264 spin_unlock_irq(&rq->lock);
7265 complete(&req->done);
7266 spin_lock_irq(&rq->lock);
7268 spin_unlock_irq(&rq->lock);
7272 case CPU_DYING_FROZEN:
7273 /* Update our root-domain */
7275 spin_lock_irqsave(&rq->lock, flags);
7277 BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
7280 spin_unlock_irqrestore(&rq->lock, flags);
7287 /* Register at highest priority so that task migration (migrate_all_tasks)
7288 * happens before everything else.
7290 static struct notifier_block __cpuinitdata migration_notifier = {
7291 .notifier_call = migration_call,
7295 static int __init migration_init(void)
7297 void *cpu = (void *)(long)smp_processor_id();
7300 /* Start one for the boot CPU: */
7301 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
7302 BUG_ON(err == NOTIFY_BAD);
7303 migration_call(&migration_notifier, CPU_ONLINE, cpu);
7304 register_cpu_notifier(&migration_notifier);
7308 early_initcall(migration_init);
7313 #ifdef CONFIG_SCHED_DEBUG
7315 static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
7316 struct cpumask *groupmask)
7318 struct sched_group *group = sd->groups;
7321 cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
7322 cpumask_clear(groupmask);
7324 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
7326 if (!(sd->flags & SD_LOAD_BALANCE)) {
7327 printk("does not load-balance\n");
7329 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
7334 printk(KERN_CONT "span %s level %s\n", str, sd->name);
7336 if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
7337 printk(KERN_ERR "ERROR: domain->span does not contain "
7340 if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
7341 printk(KERN_ERR "ERROR: domain->groups does not contain"
7345 printk(KERN_DEBUG "%*s groups:", level + 1, "");
7349 printk(KERN_ERR "ERROR: group is NULL\n");
7353 if (!group->__cpu_power) {
7354 printk(KERN_CONT "\n");
7355 printk(KERN_ERR "ERROR: domain->cpu_power not "
7360 if (!cpumask_weight(sched_group_cpus(group))) {
7361 printk(KERN_CONT "\n");
7362 printk(KERN_ERR "ERROR: empty group\n");
7366 if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
7367 printk(KERN_CONT "\n");
7368 printk(KERN_ERR "ERROR: repeated CPUs\n");
7372 cpumask_or(groupmask, groupmask, sched_group_cpus(group));
7374 cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
7376 printk(KERN_CONT " %s", str);
7377 if (group->__cpu_power != SCHED_LOAD_SCALE) {
7378 printk(KERN_CONT " (__cpu_power = %d)",
7379 group->__cpu_power);
7382 group = group->next;
7383 } while (group != sd->groups);
7384 printk(KERN_CONT "\n");
7386 if (!cpumask_equal(sched_domain_span(sd), groupmask))
7387 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
7390 !cpumask_subset(groupmask, sched_domain_span(sd->parent)))
7391 printk(KERN_ERR "ERROR: parent span is not a superset "
7392 "of domain->span\n");
7396 static void sched_domain_debug(struct sched_domain *sd, int cpu)
7398 cpumask_var_t groupmask;
7402 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
7406 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
7408 if (!alloc_cpumask_var(&groupmask, GFP_KERNEL)) {
7409 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
7414 if (sched_domain_debug_one(sd, cpu, level, groupmask))
7421 free_cpumask_var(groupmask);
7423 #else /* !CONFIG_SCHED_DEBUG */
7424 # define sched_domain_debug(sd, cpu) do { } while (0)
7425 #endif /* CONFIG_SCHED_DEBUG */
7427 static int sd_degenerate(struct sched_domain *sd)
7429 if (cpumask_weight(sched_domain_span(sd)) == 1)
7432 /* Following flags need at least 2 groups */
7433 if (sd->flags & (SD_LOAD_BALANCE |
7434 SD_BALANCE_NEWIDLE |
7438 SD_SHARE_PKG_RESOURCES)) {
7439 if (sd->groups != sd->groups->next)
7443 /* Following flags don't use groups */
7444 if (sd->flags & (SD_WAKE_IDLE |
7453 sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
7455 unsigned long cflags = sd->flags, pflags = parent->flags;
7457 if (sd_degenerate(parent))
7460 if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
7463 /* Does parent contain flags not in child? */
7464 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7465 if (cflags & SD_WAKE_AFFINE)
7466 pflags &= ~SD_WAKE_BALANCE;
7467 /* Flags needing groups don't count if only 1 group in parent */
7468 if (parent->groups == parent->groups->next) {
7469 pflags &= ~(SD_LOAD_BALANCE |
7470 SD_BALANCE_NEWIDLE |
7474 SD_SHARE_PKG_RESOURCES);
7475 if (nr_node_ids == 1)
7476 pflags &= ~SD_SERIALIZE;
7478 if (~cflags & pflags)
7484 static void free_rootdomain(struct root_domain *rd)
7486 cpupri_cleanup(&rd->cpupri);
7488 free_cpumask_var(rd->rto_mask);
7489 free_cpumask_var(rd->online);
7490 free_cpumask_var(rd->span);
7494 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
7496 struct root_domain *old_rd = NULL;
7497 unsigned long flags;
7499 spin_lock_irqsave(&rq->lock, flags);
7504 if (cpumask_test_cpu(rq->cpu, old_rd->online))
7507 cpumask_clear_cpu(rq->cpu, old_rd->span);
7510 * If we dont want to free the old_rt yet then
7511 * set old_rd to NULL to skip the freeing later
7514 if (!atomic_dec_and_test(&old_rd->refcount))
7518 atomic_inc(&rd->refcount);
7521 cpumask_set_cpu(rq->cpu, rd->span);
7522 if (cpumask_test_cpu(rq->cpu, cpu_online_mask))
7525 spin_unlock_irqrestore(&rq->lock, flags);
7528 free_rootdomain(old_rd);
7531 static int __init_refok init_rootdomain(struct root_domain *rd, bool bootmem)
7533 memset(rd, 0, sizeof(*rd));
7536 alloc_bootmem_cpumask_var(&def_root_domain.span);
7537 alloc_bootmem_cpumask_var(&def_root_domain.online);
7538 alloc_bootmem_cpumask_var(&def_root_domain.rto_mask);
7539 cpupri_init(&rd->cpupri, true);
7543 if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
7545 if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
7547 if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
7550 if (cpupri_init(&rd->cpupri, false) != 0)
7555 free_cpumask_var(rd->rto_mask);
7557 free_cpumask_var(rd->online);
7559 free_cpumask_var(rd->span);
7564 static void init_defrootdomain(void)
7566 init_rootdomain(&def_root_domain, true);
7568 atomic_set(&def_root_domain.refcount, 1);
7571 static struct root_domain *alloc_rootdomain(void)
7573 struct root_domain *rd;
7575 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
7579 if (init_rootdomain(rd, false) != 0) {
7588 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7589 * hold the hotplug lock.
7592 cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
7594 struct rq *rq = cpu_rq(cpu);
7595 struct sched_domain *tmp;
7597 /* Remove the sched domains which do not contribute to scheduling. */
7598 for (tmp = sd; tmp; ) {
7599 struct sched_domain *parent = tmp->parent;
7603 if (sd_parent_degenerate(tmp, parent)) {
7604 tmp->parent = parent->parent;
7606 parent->parent->child = tmp;
7611 if (sd && sd_degenerate(sd)) {
7617 sched_domain_debug(sd, cpu);
7619 rq_attach_root(rq, rd);
7620 rcu_assign_pointer(rq->sd, sd);
7623 /* cpus with isolated domains */
7624 static cpumask_var_t cpu_isolated_map;
7626 /* Setup the mask of cpus configured for isolated domains */
7627 static int __init isolated_cpu_setup(char *str)
7629 cpulist_parse(str, cpu_isolated_map);
7633 __setup("isolcpus=", isolated_cpu_setup);
7636 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7637 * to a function which identifies what group(along with sched group) a CPU
7638 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7639 * (due to the fact that we keep track of groups covered with a struct cpumask).
7641 * init_sched_build_groups will build a circular linked list of the groups
7642 * covered by the given span, and will set each group's ->cpumask correctly,
7643 * and ->cpu_power to 0.
7646 init_sched_build_groups(const struct cpumask *span,
7647 const struct cpumask *cpu_map,
7648 int (*group_fn)(int cpu, const struct cpumask *cpu_map,
7649 struct sched_group **sg,
7650 struct cpumask *tmpmask),
7651 struct cpumask *covered, struct cpumask *tmpmask)
7653 struct sched_group *first = NULL, *last = NULL;
7656 cpumask_clear(covered);
7658 for_each_cpu(i, span) {
7659 struct sched_group *sg;
7660 int group = group_fn(i, cpu_map, &sg, tmpmask);
7663 if (cpumask_test_cpu(i, covered))
7666 cpumask_clear(sched_group_cpus(sg));
7667 sg->__cpu_power = 0;
7669 for_each_cpu(j, span) {
7670 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
7673 cpumask_set_cpu(j, covered);
7674 cpumask_set_cpu(j, sched_group_cpus(sg));
7685 #define SD_NODES_PER_DOMAIN 16
7690 * find_next_best_node - find the next node to include in a sched_domain
7691 * @node: node whose sched_domain we're building
7692 * @used_nodes: nodes already in the sched_domain
7694 * Find the next node to include in a given scheduling domain. Simply
7695 * finds the closest node not already in the @used_nodes map.
7697 * Should use nodemask_t.
7699 static int find_next_best_node(int node, nodemask_t *used_nodes)
7701 int i, n, val, min_val, best_node = 0;
7705 for (i = 0; i < nr_node_ids; i++) {
7706 /* Start at @node */
7707 n = (node + i) % nr_node_ids;
7709 if (!nr_cpus_node(n))
7712 /* Skip already used nodes */
7713 if (node_isset(n, *used_nodes))
7716 /* Simple min distance search */
7717 val = node_distance(node, n);
7719 if (val < min_val) {
7725 node_set(best_node, *used_nodes);
7730 * sched_domain_node_span - get a cpumask for a node's sched_domain
7731 * @node: node whose cpumask we're constructing
7732 * @span: resulting cpumask
7734 * Given a node, construct a good cpumask for its sched_domain to span. It
7735 * should be one that prevents unnecessary balancing, but also spreads tasks
7738 static void sched_domain_node_span(int node, struct cpumask *span)
7740 nodemask_t used_nodes;
7743 cpumask_clear(span);
7744 nodes_clear(used_nodes);
7746 cpumask_or(span, span, cpumask_of_node(node));
7747 node_set(node, used_nodes);
7749 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
7750 int next_node = find_next_best_node(node, &used_nodes);
7752 cpumask_or(span, span, cpumask_of_node(next_node));
7755 #endif /* CONFIG_NUMA */
7757 int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
7760 * The cpus mask in sched_group and sched_domain hangs off the end.
7761 * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
7762 * for nr_cpu_ids < CONFIG_NR_CPUS.
7764 struct static_sched_group {
7765 struct sched_group sg;
7766 DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
7769 struct static_sched_domain {
7770 struct sched_domain sd;
7771 DECLARE_BITMAP(span, CONFIG_NR_CPUS);
7775 * SMT sched-domains:
7777 #ifdef CONFIG_SCHED_SMT
7778 static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
7779 static DEFINE_PER_CPU(struct static_sched_group, sched_group_cpus);
7782 cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map,
7783 struct sched_group **sg, struct cpumask *unused)
7786 *sg = &per_cpu(sched_group_cpus, cpu).sg;
7789 #endif /* CONFIG_SCHED_SMT */
7792 * multi-core sched-domains:
7794 #ifdef CONFIG_SCHED_MC
7795 static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
7796 static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
7797 #endif /* CONFIG_SCHED_MC */
7799 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7801 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
7802 struct sched_group **sg, struct cpumask *mask)
7806 cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
7807 group = cpumask_first(mask);
7809 *sg = &per_cpu(sched_group_core, group).sg;
7812 #elif defined(CONFIG_SCHED_MC)
7814 cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
7815 struct sched_group **sg, struct cpumask *unused)
7818 *sg = &per_cpu(sched_group_core, cpu).sg;
7823 static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
7824 static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
7827 cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
7828 struct sched_group **sg, struct cpumask *mask)
7831 #ifdef CONFIG_SCHED_MC
7832 cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
7833 group = cpumask_first(mask);
7834 #elif defined(CONFIG_SCHED_SMT)
7835 cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
7836 group = cpumask_first(mask);
7841 *sg = &per_cpu(sched_group_phys, group).sg;
7847 * The init_sched_build_groups can't handle what we want to do with node
7848 * groups, so roll our own. Now each node has its own list of groups which
7849 * gets dynamically allocated.
7851 static DEFINE_PER_CPU(struct static_sched_domain, node_domains);
7852 static struct sched_group ***sched_group_nodes_bycpu;
7854 static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains);
7855 static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
7857 static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map,
7858 struct sched_group **sg,
7859 struct cpumask *nodemask)
7863 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(cpu)), cpu_map);
7864 group = cpumask_first(nodemask);
7867 *sg = &per_cpu(sched_group_allnodes, group).sg;
7871 static void init_numa_sched_groups_power(struct sched_group *group_head)
7873 struct sched_group *sg = group_head;
7879 for_each_cpu(j, sched_group_cpus(sg)) {
7880 struct sched_domain *sd;
7882 sd = &per_cpu(phys_domains, j).sd;
7883 if (j != cpumask_first(sched_group_cpus(sd->groups))) {
7885 * Only add "power" once for each
7891 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
7894 } while (sg != group_head);
7896 #endif /* CONFIG_NUMA */
7899 /* Free memory allocated for various sched_group structures */
7900 static void free_sched_groups(const struct cpumask *cpu_map,
7901 struct cpumask *nodemask)
7905 for_each_cpu(cpu, cpu_map) {
7906 struct sched_group **sched_group_nodes
7907 = sched_group_nodes_bycpu[cpu];
7909 if (!sched_group_nodes)
7912 for (i = 0; i < nr_node_ids; i++) {
7913 struct sched_group *oldsg, *sg = sched_group_nodes[i];
7915 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
7916 if (cpumask_empty(nodemask))
7926 if (oldsg != sched_group_nodes[i])
7929 kfree(sched_group_nodes);
7930 sched_group_nodes_bycpu[cpu] = NULL;
7933 #else /* !CONFIG_NUMA */
7934 static void free_sched_groups(const struct cpumask *cpu_map,
7935 struct cpumask *nodemask)
7938 #endif /* CONFIG_NUMA */
7941 * Initialize sched groups cpu_power.
7943 * cpu_power indicates the capacity of sched group, which is used while
7944 * distributing the load between different sched groups in a sched domain.
7945 * Typically cpu_power for all the groups in a sched domain will be same unless
7946 * there are asymmetries in the topology. If there are asymmetries, group
7947 * having more cpu_power will pickup more load compared to the group having
7950 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7951 * the maximum number of tasks a group can handle in the presence of other idle
7952 * or lightly loaded groups in the same sched domain.
7954 static void init_sched_groups_power(int cpu, struct sched_domain *sd)
7956 struct sched_domain *child;
7957 struct sched_group *group;
7959 WARN_ON(!sd || !sd->groups);
7961 if (cpu != cpumask_first(sched_group_cpus(sd->groups)))
7966 sd->groups->__cpu_power = 0;
7969 * For perf policy, if the groups in child domain share resources
7970 * (for example cores sharing some portions of the cache hierarchy
7971 * or SMT), then set this domain groups cpu_power such that each group
7972 * can handle only one task, when there are other idle groups in the
7973 * same sched domain.
7975 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
7977 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
7978 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
7983 * add cpu_power of each child group to this groups cpu_power
7985 group = child->groups;
7987 sg_inc_cpu_power(sd->groups, group->__cpu_power);
7988 group = group->next;
7989 } while (group != child->groups);
7993 * Initializers for schedule domains
7994 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7997 #ifdef CONFIG_SCHED_DEBUG
7998 # define SD_INIT_NAME(sd, type) sd->name = #type
8000 # define SD_INIT_NAME(sd, type) do { } while (0)
8003 #define SD_INIT(sd, type) sd_init_##type(sd)
8005 #define SD_INIT_FUNC(type) \
8006 static noinline void sd_init_##type(struct sched_domain *sd) \
8008 memset(sd, 0, sizeof(*sd)); \
8009 *sd = SD_##type##_INIT; \
8010 sd->level = SD_LV_##type; \
8011 SD_INIT_NAME(sd, type); \
8016 SD_INIT_FUNC(ALLNODES)
8019 #ifdef CONFIG_SCHED_SMT
8020 SD_INIT_FUNC(SIBLING)
8022 #ifdef CONFIG_SCHED_MC
8026 static int default_relax_domain_level = -1;
8028 static int __init setup_relax_domain_level(char *str)
8032 val = simple_strtoul(str, NULL, 0);
8033 if (val < SD_LV_MAX)
8034 default_relax_domain_level = val;
8038 __setup("relax_domain_level=", setup_relax_domain_level);
8040 static void set_domain_attribute(struct sched_domain *sd,
8041 struct sched_domain_attr *attr)
8045 if (!attr || attr->relax_domain_level < 0) {
8046 if (default_relax_domain_level < 0)
8049 request = default_relax_domain_level;
8051 request = attr->relax_domain_level;
8052 if (request < sd->level) {
8053 /* turn off idle balance on this domain */
8054 sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
8056 /* turn on idle balance on this domain */
8057 sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
8062 * Build sched domains for a given set of cpus and attach the sched domains
8063 * to the individual cpus
8065 static int __build_sched_domains(const struct cpumask *cpu_map,
8066 struct sched_domain_attr *attr)
8068 int i, err = -ENOMEM;
8069 struct root_domain *rd;
8070 cpumask_var_t nodemask, this_sibling_map, this_core_map, send_covered,
8073 cpumask_var_t domainspan, covered, notcovered;
8074 struct sched_group **sched_group_nodes = NULL;
8075 int sd_allnodes = 0;
8077 if (!alloc_cpumask_var(&domainspan, GFP_KERNEL))
8079 if (!alloc_cpumask_var(&covered, GFP_KERNEL))
8080 goto free_domainspan;
8081 if (!alloc_cpumask_var(¬covered, GFP_KERNEL))
8085 if (!alloc_cpumask_var(&nodemask, GFP_KERNEL))
8086 goto free_notcovered;
8087 if (!alloc_cpumask_var(&this_sibling_map, GFP_KERNEL))
8089 if (!alloc_cpumask_var(&this_core_map, GFP_KERNEL))
8090 goto free_this_sibling_map;
8091 if (!alloc_cpumask_var(&send_covered, GFP_KERNEL))
8092 goto free_this_core_map;
8093 if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
8094 goto free_send_covered;
8098 * Allocate the per-node list of sched groups
8100 sched_group_nodes = kcalloc(nr_node_ids, sizeof(struct sched_group *),
8102 if (!sched_group_nodes) {
8103 printk(KERN_WARNING "Can not alloc sched group node list\n");
8108 rd = alloc_rootdomain();
8110 printk(KERN_WARNING "Cannot alloc root domain\n");
8111 goto free_sched_groups;
8115 sched_group_nodes_bycpu[cpumask_first(cpu_map)] = sched_group_nodes;
8119 * Set up domains for cpus specified by the cpu_map.
8121 for_each_cpu(i, cpu_map) {
8122 struct sched_domain *sd = NULL, *p;
8124 cpumask_and(nodemask, cpumask_of_node(cpu_to_node(i)), cpu_map);
8127 if (cpumask_weight(cpu_map) >
8128 SD_NODES_PER_DOMAIN*cpumask_weight(nodemask)) {
8129 sd = &per_cpu(allnodes_domains, i).sd;
8130 SD_INIT(sd, ALLNODES);
8131 set_domain_attribute(sd, attr);
8132 cpumask_copy(sched_domain_span(sd), cpu_map);
8133 cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
8139 sd = &per_cpu(node_domains, i).sd;
8141 set_domain_attribute(sd, attr);
8142 sched_domain_node_span(cpu_to_node(i), sched_domain_span(sd));
8146 cpumask_and(sched_domain_span(sd),
8147 sched_domain_span(sd), cpu_map);
8151 sd = &per_cpu(phys_domains, i).sd;
8153 set_domain_attribute(sd, attr);
8154 cpumask_copy(sched_domain_span(sd), nodemask);
8158 cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
8160 #ifdef CONFIG_SCHED_MC
8162 sd = &per_cpu(core_domains, i).sd;
8164 set_domain_attribute(sd, attr);
8165 cpumask_and(sched_domain_span(sd), cpu_map,
8166 cpu_coregroup_mask(i));
8169 cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
8172 #ifdef CONFIG_SCHED_SMT
8174 sd = &per_cpu(cpu_domains, i).sd;
8175 SD_INIT(sd, SIBLING);
8176 set_domain_attribute(sd, attr);
8177 cpumask_and(sched_domain_span(sd),
8178 topology_thread_cpumask(i), cpu_map);
8181 cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
8185 #ifdef CONFIG_SCHED_SMT
8186 /* Set up CPU (sibling) groups */
8187 for_each_cpu(i, cpu_map) {
8188 cpumask_and(this_sibling_map,
8189 topology_thread_cpumask(i), cpu_map);
8190 if (i != cpumask_first(this_sibling_map))
8193 init_sched_build_groups(this_sibling_map, cpu_map,
8195 send_covered, tmpmask);
8199 #ifdef CONFIG_SCHED_MC
8200 /* Set up multi-core groups */
8201 for_each_cpu(i, cpu_map) {
8202 cpumask_and(this_core_map, cpu_coregroup_mask(i), cpu_map);
8203 if (i != cpumask_first(this_core_map))
8206 init_sched_build_groups(this_core_map, cpu_map,
8208 send_covered, tmpmask);
8212 /* Set up physical groups */
8213 for (i = 0; i < nr_node_ids; i++) {
8214 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
8215 if (cpumask_empty(nodemask))
8218 init_sched_build_groups(nodemask, cpu_map,
8220 send_covered, tmpmask);
8224 /* Set up node groups */
8226 init_sched_build_groups(cpu_map, cpu_map,
8227 &cpu_to_allnodes_group,
8228 send_covered, tmpmask);
8231 for (i = 0; i < nr_node_ids; i++) {
8232 /* Set up node groups */
8233 struct sched_group *sg, *prev;
8236 cpumask_clear(covered);
8237 cpumask_and(nodemask, cpumask_of_node(i), cpu_map);
8238 if (cpumask_empty(nodemask)) {
8239 sched_group_nodes[i] = NULL;
8243 sched_domain_node_span(i, domainspan);
8244 cpumask_and(domainspan, domainspan, cpu_map);
8246 sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
8249 printk(KERN_WARNING "Can not alloc domain group for "
8253 sched_group_nodes[i] = sg;
8254 for_each_cpu(j, nodemask) {
8255 struct sched_domain *sd;
8257 sd = &per_cpu(node_domains, j).sd;
8260 sg->__cpu_power = 0;
8261 cpumask_copy(sched_group_cpus(sg), nodemask);
8263 cpumask_or(covered, covered, nodemask);
8266 for (j = 0; j < nr_node_ids; j++) {
8267 int n = (i + j) % nr_node_ids;
8269 cpumask_complement(notcovered, covered);
8270 cpumask_and(tmpmask, notcovered, cpu_map);
8271 cpumask_and(tmpmask, tmpmask, domainspan);
8272 if (cpumask_empty(tmpmask))
8275 cpumask_and(tmpmask, tmpmask, cpumask_of_node(n));
8276 if (cpumask_empty(tmpmask))
8279 sg = kmalloc_node(sizeof(struct sched_group) +
8284 "Can not alloc domain group for node %d\n", j);
8287 sg->__cpu_power = 0;
8288 cpumask_copy(sched_group_cpus(sg), tmpmask);
8289 sg->next = prev->next;
8290 cpumask_or(covered, covered, tmpmask);
8297 /* Calculate CPU power for physical packages and nodes */
8298 #ifdef CONFIG_SCHED_SMT
8299 for_each_cpu(i, cpu_map) {
8300 struct sched_domain *sd = &per_cpu(cpu_domains, i).sd;
8302 init_sched_groups_power(i, sd);
8305 #ifdef CONFIG_SCHED_MC
8306 for_each_cpu(i, cpu_map) {
8307 struct sched_domain *sd = &per_cpu(core_domains, i).sd;
8309 init_sched_groups_power(i, sd);
8313 for_each_cpu(i, cpu_map) {
8314 struct sched_domain *sd = &per_cpu(phys_domains, i).sd;
8316 init_sched_groups_power(i, sd);
8320 for (i = 0; i < nr_node_ids; i++)
8321 init_numa_sched_groups_power(sched_group_nodes[i]);
8324 struct sched_group *sg;
8326 cpu_to_allnodes_group(cpumask_first(cpu_map), cpu_map, &sg,
8328 init_numa_sched_groups_power(sg);
8332 /* Attach the domains */
8333 for_each_cpu(i, cpu_map) {
8334 struct sched_domain *sd;
8335 #ifdef CONFIG_SCHED_SMT
8336 sd = &per_cpu(cpu_domains, i).sd;
8337 #elif defined(CONFIG_SCHED_MC)
8338 sd = &per_cpu(core_domains, i).sd;
8340 sd = &per_cpu(phys_domains, i).sd;
8342 cpu_attach_domain(sd, rd, i);
8348 free_cpumask_var(tmpmask);
8350 free_cpumask_var(send_covered);
8352 free_cpumask_var(this_core_map);
8353 free_this_sibling_map:
8354 free_cpumask_var(this_sibling_map);
8356 free_cpumask_var(nodemask);
8359 free_cpumask_var(notcovered);
8361 free_cpumask_var(covered);
8363 free_cpumask_var(domainspan);
8370 kfree(sched_group_nodes);
8376 free_sched_groups(cpu_map, tmpmask);
8377 free_rootdomain(rd);
8382 static int build_sched_domains(const struct cpumask *cpu_map)
8384 return __build_sched_domains(cpu_map, NULL);
8387 static struct cpumask *doms_cur; /* current sched domains */
8388 static int ndoms_cur; /* number of sched domains in 'doms_cur' */
8389 static struct sched_domain_attr *dattr_cur;
8390 /* attribues of custom domains in 'doms_cur' */
8393 * Special case: If a kmalloc of a doms_cur partition (array of
8394 * cpumask) fails, then fallback to a single sched domain,
8395 * as determined by the single cpumask fallback_doms.
8397 static cpumask_var_t fallback_doms;
8400 * arch_update_cpu_topology lets virtualized architectures update the
8401 * cpu core maps. It is supposed to return 1 if the topology changed
8402 * or 0 if it stayed the same.
8404 int __attribute__((weak)) arch_update_cpu_topology(void)
8410 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
8411 * For now this just excludes isolated cpus, but could be used to
8412 * exclude other special cases in the future.
8414 static int arch_init_sched_domains(const struct cpumask *cpu_map)
8418 arch_update_cpu_topology();
8420 doms_cur = kmalloc(cpumask_size(), GFP_KERNEL);
8422 doms_cur = fallback_doms;
8423 cpumask_andnot(doms_cur, cpu_map, cpu_isolated_map);
8425 err = build_sched_domains(doms_cur);
8426 register_sched_domain_sysctl();
8431 static void arch_destroy_sched_domains(const struct cpumask *cpu_map,
8432 struct cpumask *tmpmask)
8434 free_sched_groups(cpu_map, tmpmask);
8438 * Detach sched domains from a group of cpus specified in cpu_map
8439 * These cpus will now be attached to the NULL domain
8441 static void detach_destroy_domains(const struct cpumask *cpu_map)
8443 /* Save because hotplug lock held. */
8444 static DECLARE_BITMAP(tmpmask, CONFIG_NR_CPUS);
8447 for_each_cpu(i, cpu_map)
8448 cpu_attach_domain(NULL, &def_root_domain, i);
8449 synchronize_sched();
8450 arch_destroy_sched_domains(cpu_map, to_cpumask(tmpmask));
8453 /* handle null as "default" */
8454 static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
8455 struct sched_domain_attr *new, int idx_new)
8457 struct sched_domain_attr tmp;
8464 return !memcmp(cur ? (cur + idx_cur) : &tmp,
8465 new ? (new + idx_new) : &tmp,
8466 sizeof(struct sched_domain_attr));
8470 * Partition sched domains as specified by the 'ndoms_new'
8471 * cpumasks in the array doms_new[] of cpumasks. This compares
8472 * doms_new[] to the current sched domain partitioning, doms_cur[].
8473 * It destroys each deleted domain and builds each new domain.
8475 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8476 * The masks don't intersect (don't overlap.) We should setup one
8477 * sched domain for each mask. CPUs not in any of the cpumasks will
8478 * not be load balanced. If the same cpumask appears both in the
8479 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8482 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8483 * ownership of it and will kfree it when done with it. If the caller
8484 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8485 * ndoms_new == 1, and partition_sched_domains() will fallback to
8486 * the single partition 'fallback_doms', it also forces the domains
8489 * If doms_new == NULL it will be replaced with cpu_online_mask.
8490 * ndoms_new == 0 is a special case for destroying existing domains,
8491 * and it will not create the default domain.
8493 * Call with hotplug lock held
8495 /* FIXME: Change to struct cpumask *doms_new[] */
8496 void partition_sched_domains(int ndoms_new, struct cpumask *doms_new,
8497 struct sched_domain_attr *dattr_new)
8502 mutex_lock(&sched_domains_mutex);
8504 /* always unregister in case we don't destroy any domains */
8505 unregister_sched_domain_sysctl();
8507 /* Let architecture update cpu core mappings. */
8508 new_topology = arch_update_cpu_topology();
8510 n = doms_new ? ndoms_new : 0;
8512 /* Destroy deleted domains */
8513 for (i = 0; i < ndoms_cur; i++) {
8514 for (j = 0; j < n && !new_topology; j++) {
8515 if (cpumask_equal(&doms_cur[i], &doms_new[j])
8516 && dattrs_equal(dattr_cur, i, dattr_new, j))
8519 /* no match - a current sched domain not in new doms_new[] */
8520 detach_destroy_domains(doms_cur + i);
8525 if (doms_new == NULL) {
8527 doms_new = fallback_doms;
8528 cpumask_andnot(&doms_new[0], cpu_online_mask, cpu_isolated_map);
8529 WARN_ON_ONCE(dattr_new);
8532 /* Build new domains */
8533 for (i = 0; i < ndoms_new; i++) {
8534 for (j = 0; j < ndoms_cur && !new_topology; j++) {
8535 if (cpumask_equal(&doms_new[i], &doms_cur[j])
8536 && dattrs_equal(dattr_new, i, dattr_cur, j))
8539 /* no match - add a new doms_new */
8540 __build_sched_domains(doms_new + i,
8541 dattr_new ? dattr_new + i : NULL);
8546 /* Remember the new sched domains */
8547 if (doms_cur != fallback_doms)
8549 kfree(dattr_cur); /* kfree(NULL) is safe */
8550 doms_cur = doms_new;
8551 dattr_cur = dattr_new;
8552 ndoms_cur = ndoms_new;
8554 register_sched_domain_sysctl();
8556 mutex_unlock(&sched_domains_mutex);
8559 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8560 static void arch_reinit_sched_domains(void)
8564 /* Destroy domains first to force the rebuild */
8565 partition_sched_domains(0, NULL, NULL);
8567 rebuild_sched_domains();
8571 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
8573 unsigned int level = 0;
8575 if (sscanf(buf, "%u", &level) != 1)
8579 * level is always be positive so don't check for
8580 * level < POWERSAVINGS_BALANCE_NONE which is 0
8581 * What happens on 0 or 1 byte write,
8582 * need to check for count as well?
8585 if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
8589 sched_smt_power_savings = level;
8591 sched_mc_power_savings = level;
8593 arch_reinit_sched_domains();
8598 #ifdef CONFIG_SCHED_MC
8599 static ssize_t sched_mc_power_savings_show(struct sysdev_class *class,
8602 return sprintf(page, "%u\n", sched_mc_power_savings);
8604 static ssize_t sched_mc_power_savings_store(struct sysdev_class *class,
8605 const char *buf, size_t count)
8607 return sched_power_savings_store(buf, count, 0);
8609 static SYSDEV_CLASS_ATTR(sched_mc_power_savings, 0644,
8610 sched_mc_power_savings_show,
8611 sched_mc_power_savings_store);
8614 #ifdef CONFIG_SCHED_SMT
8615 static ssize_t sched_smt_power_savings_show(struct sysdev_class *dev,
8618 return sprintf(page, "%u\n", sched_smt_power_savings);
8620 static ssize_t sched_smt_power_savings_store(struct sysdev_class *dev,
8621 const char *buf, size_t count)
8623 return sched_power_savings_store(buf, count, 1);
8625 static SYSDEV_CLASS_ATTR(sched_smt_power_savings, 0644,
8626 sched_smt_power_savings_show,
8627 sched_smt_power_savings_store);
8630 int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
8634 #ifdef CONFIG_SCHED_SMT
8636 err = sysfs_create_file(&cls->kset.kobj,
8637 &attr_sched_smt_power_savings.attr);
8639 #ifdef CONFIG_SCHED_MC
8640 if (!err && mc_capable())
8641 err = sysfs_create_file(&cls->kset.kobj,
8642 &attr_sched_mc_power_savings.attr);
8646 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
8648 #ifndef CONFIG_CPUSETS
8650 * Add online and remove offline CPUs from the scheduler domains.
8651 * When cpusets are enabled they take over this function.
8653 static int update_sched_domains(struct notifier_block *nfb,
8654 unsigned long action, void *hcpu)
8658 case CPU_ONLINE_FROZEN:
8660 case CPU_DEAD_FROZEN:
8661 partition_sched_domains(1, NULL, NULL);
8670 static int update_runtime(struct notifier_block *nfb,
8671 unsigned long action, void *hcpu)
8673 int cpu = (int)(long)hcpu;
8676 case CPU_DOWN_PREPARE:
8677 case CPU_DOWN_PREPARE_FROZEN:
8678 disable_runtime(cpu_rq(cpu));
8681 case CPU_DOWN_FAILED:
8682 case CPU_DOWN_FAILED_FROZEN:
8684 case CPU_ONLINE_FROZEN:
8685 enable_runtime(cpu_rq(cpu));
8693 void __init sched_init_smp(void)
8695 cpumask_var_t non_isolated_cpus;
8697 alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
8699 #if defined(CONFIG_NUMA)
8700 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
8702 BUG_ON(sched_group_nodes_bycpu == NULL);
8705 mutex_lock(&sched_domains_mutex);
8706 arch_init_sched_domains(cpu_online_mask);
8707 cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
8708 if (cpumask_empty(non_isolated_cpus))
8709 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
8710 mutex_unlock(&sched_domains_mutex);
8713 #ifndef CONFIG_CPUSETS
8714 /* XXX: Theoretical race here - CPU may be hotplugged now */
8715 hotcpu_notifier(update_sched_domains, 0);
8718 /* RT runtime code needs to handle some hotplug events */
8719 hotcpu_notifier(update_runtime, 0);
8723 /* Move init over to a non-isolated CPU */
8724 if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
8726 sched_init_granularity();
8727 free_cpumask_var(non_isolated_cpus);
8729 alloc_cpumask_var(&fallback_doms, GFP_KERNEL);
8730 init_sched_rt_class();
8733 void __init sched_init_smp(void)
8735 sched_init_granularity();
8737 #endif /* CONFIG_SMP */
8739 const_debug unsigned int sysctl_timer_migration = 1;
8741 int in_sched_functions(unsigned long addr)
8743 return in_lock_functions(addr) ||
8744 (addr >= (unsigned long)__sched_text_start
8745 && addr < (unsigned long)__sched_text_end);
8748 static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
8750 cfs_rq->tasks_timeline = RB_ROOT;
8751 INIT_LIST_HEAD(&cfs_rq->tasks);
8752 #ifdef CONFIG_FAIR_GROUP_SCHED
8755 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
8758 static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
8760 struct rt_prio_array *array;
8763 array = &rt_rq->active;
8764 for (i = 0; i < MAX_RT_PRIO; i++) {
8765 INIT_LIST_HEAD(array->queue + i);
8766 __clear_bit(i, array->bitmap);
8768 /* delimiter for bitsearch: */
8769 __set_bit(MAX_RT_PRIO, array->bitmap);
8771 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8772 rt_rq->highest_prio.curr = MAX_RT_PRIO;
8774 rt_rq->highest_prio.next = MAX_RT_PRIO;
8778 rt_rq->rt_nr_migratory = 0;
8779 rt_rq->overloaded = 0;
8780 plist_head_init(&rq->rt.pushable_tasks, &rq->lock);
8784 rt_rq->rt_throttled = 0;
8785 rt_rq->rt_runtime = 0;
8786 spin_lock_init(&rt_rq->rt_runtime_lock);
8788 #ifdef CONFIG_RT_GROUP_SCHED
8789 rt_rq->rt_nr_boosted = 0;
8794 #ifdef CONFIG_FAIR_GROUP_SCHED
8795 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
8796 struct sched_entity *se, int cpu, int add,
8797 struct sched_entity *parent)
8799 struct rq *rq = cpu_rq(cpu);
8800 tg->cfs_rq[cpu] = cfs_rq;
8801 init_cfs_rq(cfs_rq, rq);
8804 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
8807 /* se could be NULL for init_task_group */
8812 se->cfs_rq = &rq->cfs;
8814 se->cfs_rq = parent->my_q;
8817 se->load.weight = tg->shares;
8818 se->load.inv_weight = 0;
8819 se->parent = parent;
8823 #ifdef CONFIG_RT_GROUP_SCHED
8824 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
8825 struct sched_rt_entity *rt_se, int cpu, int add,
8826 struct sched_rt_entity *parent)
8828 struct rq *rq = cpu_rq(cpu);
8830 tg->rt_rq[cpu] = rt_rq;
8831 init_rt_rq(rt_rq, rq);
8833 rt_rq->rt_se = rt_se;
8834 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
8836 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
8838 tg->rt_se[cpu] = rt_se;
8843 rt_se->rt_rq = &rq->rt;
8845 rt_se->rt_rq = parent->my_q;
8847 rt_se->my_q = rt_rq;
8848 rt_se->parent = parent;
8849 INIT_LIST_HEAD(&rt_se->run_list);
8853 void __init sched_init(void)
8856 unsigned long alloc_size = 0, ptr;
8858 #ifdef CONFIG_FAIR_GROUP_SCHED
8859 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8861 #ifdef CONFIG_RT_GROUP_SCHED
8862 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
8864 #ifdef CONFIG_USER_SCHED
8867 #ifdef CONFIG_CPUMASK_OFFSTACK
8868 alloc_size += num_possible_cpus() * cpumask_size();
8871 * As sched_init() is called before page_alloc is setup,
8872 * we use alloc_bootmem().
8875 ptr = (unsigned long)alloc_bootmem(alloc_size);
8877 #ifdef CONFIG_FAIR_GROUP_SCHED
8878 init_task_group.se = (struct sched_entity **)ptr;
8879 ptr += nr_cpu_ids * sizeof(void **);
8881 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
8882 ptr += nr_cpu_ids * sizeof(void **);
8884 #ifdef CONFIG_USER_SCHED
8885 root_task_group.se = (struct sched_entity **)ptr;
8886 ptr += nr_cpu_ids * sizeof(void **);
8888 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
8889 ptr += nr_cpu_ids * sizeof(void **);
8890 #endif /* CONFIG_USER_SCHED */
8891 #endif /* CONFIG_FAIR_GROUP_SCHED */
8892 #ifdef CONFIG_RT_GROUP_SCHED
8893 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
8894 ptr += nr_cpu_ids * sizeof(void **);
8896 init_task_group.rt_rq = (struct rt_rq **)ptr;
8897 ptr += nr_cpu_ids * sizeof(void **);
8899 #ifdef CONFIG_USER_SCHED
8900 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
8901 ptr += nr_cpu_ids * sizeof(void **);
8903 root_task_group.rt_rq = (struct rt_rq **)ptr;
8904 ptr += nr_cpu_ids * sizeof(void **);
8905 #endif /* CONFIG_USER_SCHED */
8906 #endif /* CONFIG_RT_GROUP_SCHED */
8907 #ifdef CONFIG_CPUMASK_OFFSTACK
8908 for_each_possible_cpu(i) {
8909 per_cpu(load_balance_tmpmask, i) = (void *)ptr;
8910 ptr += cpumask_size();
8912 #endif /* CONFIG_CPUMASK_OFFSTACK */
8916 init_defrootdomain();
8919 init_rt_bandwidth(&def_rt_bandwidth,
8920 global_rt_period(), global_rt_runtime());
8922 #ifdef CONFIG_RT_GROUP_SCHED
8923 init_rt_bandwidth(&init_task_group.rt_bandwidth,
8924 global_rt_period(), global_rt_runtime());
8925 #ifdef CONFIG_USER_SCHED
8926 init_rt_bandwidth(&root_task_group.rt_bandwidth,
8927 global_rt_period(), RUNTIME_INF);
8928 #endif /* CONFIG_USER_SCHED */
8929 #endif /* CONFIG_RT_GROUP_SCHED */
8931 #ifdef CONFIG_GROUP_SCHED
8932 list_add(&init_task_group.list, &task_groups);
8933 INIT_LIST_HEAD(&init_task_group.children);
8935 #ifdef CONFIG_USER_SCHED
8936 INIT_LIST_HEAD(&root_task_group.children);
8937 init_task_group.parent = &root_task_group;
8938 list_add(&init_task_group.siblings, &root_task_group.children);
8939 #endif /* CONFIG_USER_SCHED */
8940 #endif /* CONFIG_GROUP_SCHED */
8942 for_each_possible_cpu(i) {
8946 spin_lock_init(&rq->lock);
8948 init_cfs_rq(&rq->cfs, rq);
8949 init_rt_rq(&rq->rt, rq);
8950 #ifdef CONFIG_FAIR_GROUP_SCHED
8951 init_task_group.shares = init_task_group_load;
8952 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
8953 #ifdef CONFIG_CGROUP_SCHED
8955 * How much cpu bandwidth does init_task_group get?
8957 * In case of task-groups formed thr' the cgroup filesystem, it
8958 * gets 100% of the cpu resources in the system. This overall
8959 * system cpu resource is divided among the tasks of
8960 * init_task_group and its child task-groups in a fair manner,
8961 * based on each entity's (task or task-group's) weight
8962 * (se->load.weight).
8964 * In other words, if init_task_group has 10 tasks of weight
8965 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8966 * then A0's share of the cpu resource is:
8968 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8970 * We achieve this by letting init_task_group's tasks sit
8971 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8973 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
8974 #elif defined CONFIG_USER_SCHED
8975 root_task_group.shares = NICE_0_LOAD;
8976 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
8978 * In case of task-groups formed thr' the user id of tasks,
8979 * init_task_group represents tasks belonging to root user.
8980 * Hence it forms a sibling of all subsequent groups formed.
8981 * In this case, init_task_group gets only a fraction of overall
8982 * system cpu resource, based on the weight assigned to root
8983 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8984 * by letting tasks of init_task_group sit in a separate cfs_rq
8985 * (init_cfs_rq) and having one entity represent this group of
8986 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8988 init_tg_cfs_entry(&init_task_group,
8989 &per_cpu(init_cfs_rq, i),
8990 &per_cpu(init_sched_entity, i), i, 1,
8991 root_task_group.se[i]);
8994 #endif /* CONFIG_FAIR_GROUP_SCHED */
8996 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
8997 #ifdef CONFIG_RT_GROUP_SCHED
8998 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
8999 #ifdef CONFIG_CGROUP_SCHED
9000 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
9001 #elif defined CONFIG_USER_SCHED
9002 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
9003 init_tg_rt_entry(&init_task_group,
9004 &per_cpu(init_rt_rq, i),
9005 &per_cpu(init_sched_rt_entity, i), i, 1,
9006 root_task_group.rt_se[i]);
9010 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
9011 rq->cpu_load[j] = 0;
9015 rq->active_balance = 0;
9016 rq->next_balance = jiffies;
9020 rq->migration_thread = NULL;
9021 INIT_LIST_HEAD(&rq->migration_queue);
9022 rq_attach_root(rq, &def_root_domain);
9025 atomic_set(&rq->nr_iowait, 0);
9028 set_load_weight(&init_task);
9030 #ifdef CONFIG_PREEMPT_NOTIFIERS
9031 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
9035 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
9038 #ifdef CONFIG_RT_MUTEXES
9039 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
9043 * The boot idle thread does lazy MMU switching as well:
9045 atomic_inc(&init_mm.mm_count);
9046 enter_lazy_tlb(&init_mm, current);
9049 * Make us the idle thread. Technically, schedule() should not be
9050 * called from this thread, however somewhere below it might be,
9051 * but because we are the idle thread, we just pick up running again
9052 * when this runqueue becomes "idle".
9054 init_idle(current, smp_processor_id());
9056 * During early bootup we pretend to be a normal task:
9058 current->sched_class = &fair_sched_class;
9060 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
9061 alloc_bootmem_cpumask_var(&nohz_cpu_mask);
9064 alloc_bootmem_cpumask_var(&nohz.cpu_mask);
9066 alloc_bootmem_cpumask_var(&cpu_isolated_map);
9069 scheduler_running = 1;
9072 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
9073 void __might_sleep(char *file, int line)
9076 static unsigned long prev_jiffy; /* ratelimiting */
9078 if ((!in_atomic() && !irqs_disabled()) ||
9079 system_state != SYSTEM_RUNNING || oops_in_progress)
9081 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
9083 prev_jiffy = jiffies;
9086 "BUG: sleeping function called from invalid context at %s:%d\n",
9089 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
9090 in_atomic(), irqs_disabled(),
9091 current->pid, current->comm);
9093 debug_show_held_locks(current);
9094 if (irqs_disabled())
9095 print_irqtrace_events(current);
9099 EXPORT_SYMBOL(__might_sleep);
9102 #ifdef CONFIG_MAGIC_SYSRQ
9103 static void normalize_task(struct rq *rq, struct task_struct *p)
9107 update_rq_clock(rq);
9108 on_rq = p->se.on_rq;
9110 deactivate_task(rq, p, 0);
9111 __setscheduler(rq, p, SCHED_NORMAL, 0);
9113 activate_task(rq, p, 0);
9114 resched_task(rq->curr);
9118 void normalize_rt_tasks(void)
9120 struct task_struct *g, *p;
9121 unsigned long flags;
9124 read_lock_irqsave(&tasklist_lock, flags);
9125 do_each_thread(g, p) {
9127 * Only normalize user tasks:
9132 p->se.exec_start = 0;
9133 #ifdef CONFIG_SCHEDSTATS
9134 p->se.wait_start = 0;
9135 p->se.sleep_start = 0;
9136 p->se.block_start = 0;
9141 * Renice negative nice level userspace
9144 if (TASK_NICE(p) < 0 && p->mm)
9145 set_user_nice(p, 0);
9149 spin_lock(&p->pi_lock);
9150 rq = __task_rq_lock(p);
9152 normalize_task(rq, p);
9154 __task_rq_unlock(rq);
9155 spin_unlock(&p->pi_lock);
9156 } while_each_thread(g, p);
9158 read_unlock_irqrestore(&tasklist_lock, flags);
9161 #endif /* CONFIG_MAGIC_SYSRQ */
9165 * These functions are only useful for the IA64 MCA handling.
9167 * They can only be called when the whole system has been
9168 * stopped - every CPU needs to be quiescent, and no scheduling
9169 * activity can take place. Using them for anything else would
9170 * be a serious bug, and as a result, they aren't even visible
9171 * under any other configuration.
9175 * curr_task - return the current task for a given cpu.
9176 * @cpu: the processor in question.
9178 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9180 struct task_struct *curr_task(int cpu)
9182 return cpu_curr(cpu);
9186 * set_curr_task - set the current task for a given cpu.
9187 * @cpu: the processor in question.
9188 * @p: the task pointer to set.
9190 * Description: This function must only be used when non-maskable interrupts
9191 * are serviced on a separate stack. It allows the architecture to switch the
9192 * notion of the current task on a cpu in a non-blocking manner. This function
9193 * must be called with all CPU's synchronized, and interrupts disabled, the
9194 * and caller must save the original value of the current task (see
9195 * curr_task() above) and restore that value before reenabling interrupts and
9196 * re-starting the system.
9198 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
9200 void set_curr_task(int cpu, struct task_struct *p)
9207 #ifdef CONFIG_FAIR_GROUP_SCHED
9208 static void free_fair_sched_group(struct task_group *tg)
9212 for_each_possible_cpu(i) {
9214 kfree(tg->cfs_rq[i]);
9224 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
9226 struct cfs_rq *cfs_rq;
9227 struct sched_entity *se;
9231 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
9234 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
9238 tg->shares = NICE_0_LOAD;
9240 for_each_possible_cpu(i) {
9243 cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
9244 GFP_KERNEL, cpu_to_node(i));
9248 se = kzalloc_node(sizeof(struct sched_entity),
9249 GFP_KERNEL, cpu_to_node(i));
9253 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
9262 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
9264 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
9265 &cpu_rq(cpu)->leaf_cfs_rq_list);
9268 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
9270 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
9272 #else /* !CONFG_FAIR_GROUP_SCHED */
9273 static inline void free_fair_sched_group(struct task_group *tg)
9278 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
9283 static inline void register_fair_sched_group(struct task_group *tg, int cpu)
9287 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
9290 #endif /* CONFIG_FAIR_GROUP_SCHED */
9292 #ifdef CONFIG_RT_GROUP_SCHED
9293 static void free_rt_sched_group(struct task_group *tg)
9297 destroy_rt_bandwidth(&tg->rt_bandwidth);
9299 for_each_possible_cpu(i) {
9301 kfree(tg->rt_rq[i]);
9303 kfree(tg->rt_se[i]);
9311 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
9313 struct rt_rq *rt_rq;
9314 struct sched_rt_entity *rt_se;
9318 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
9321 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
9325 init_rt_bandwidth(&tg->rt_bandwidth,
9326 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
9328 for_each_possible_cpu(i) {
9331 rt_rq = kzalloc_node(sizeof(struct rt_rq),
9332 GFP_KERNEL, cpu_to_node(i));
9336 rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
9337 GFP_KERNEL, cpu_to_node(i));
9341 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
9350 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
9352 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
9353 &cpu_rq(cpu)->leaf_rt_rq_list);
9356 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
9358 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
9360 #else /* !CONFIG_RT_GROUP_SCHED */
9361 static inline void free_rt_sched_group(struct task_group *tg)
9366 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
9371 static inline void register_rt_sched_group(struct task_group *tg, int cpu)
9375 static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
9378 #endif /* CONFIG_RT_GROUP_SCHED */
9380 #ifdef CONFIG_GROUP_SCHED
9381 static void free_sched_group(struct task_group *tg)
9383 free_fair_sched_group(tg);
9384 free_rt_sched_group(tg);
9388 /* allocate runqueue etc for a new task group */
9389 struct task_group *sched_create_group(struct task_group *parent)
9391 struct task_group *tg;
9392 unsigned long flags;
9395 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
9397 return ERR_PTR(-ENOMEM);
9399 if (!alloc_fair_sched_group(tg, parent))
9402 if (!alloc_rt_sched_group(tg, parent))
9405 spin_lock_irqsave(&task_group_lock, flags);
9406 for_each_possible_cpu(i) {
9407 register_fair_sched_group(tg, i);
9408 register_rt_sched_group(tg, i);
9410 list_add_rcu(&tg->list, &task_groups);
9412 WARN_ON(!parent); /* root should already exist */
9414 tg->parent = parent;
9415 INIT_LIST_HEAD(&tg->children);
9416 list_add_rcu(&tg->siblings, &parent->children);
9417 spin_unlock_irqrestore(&task_group_lock, flags);
9422 free_sched_group(tg);
9423 return ERR_PTR(-ENOMEM);
9426 /* rcu callback to free various structures associated with a task group */
9427 static void free_sched_group_rcu(struct rcu_head *rhp)
9429 /* now it should be safe to free those cfs_rqs */
9430 free_sched_group(container_of(rhp, struct task_group, rcu));
9433 /* Destroy runqueue etc associated with a task group */
9434 void sched_destroy_group(struct task_group *tg)
9436 unsigned long flags;
9439 spin_lock_irqsave(&task_group_lock, flags);
9440 for_each_possible_cpu(i) {
9441 unregister_fair_sched_group(tg, i);
9442 unregister_rt_sched_group(tg, i);
9444 list_del_rcu(&tg->list);
9445 list_del_rcu(&tg->siblings);
9446 spin_unlock_irqrestore(&task_group_lock, flags);
9448 /* wait for possible concurrent references to cfs_rqs complete */
9449 call_rcu(&tg->rcu, free_sched_group_rcu);
9452 /* change task's runqueue when it moves between groups.
9453 * The caller of this function should have put the task in its new group
9454 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
9455 * reflect its new group.
9457 void sched_move_task(struct task_struct *tsk)
9460 unsigned long flags;
9463 rq = task_rq_lock(tsk, &flags);
9465 update_rq_clock(rq);
9467 running = task_current(rq, tsk);
9468 on_rq = tsk->se.on_rq;
9471 dequeue_task(rq, tsk, 0);
9472 if (unlikely(running))
9473 tsk->sched_class->put_prev_task(rq, tsk);
9475 set_task_rq(tsk, task_cpu(tsk));
9477 #ifdef CONFIG_FAIR_GROUP_SCHED
9478 if (tsk->sched_class->moved_group)
9479 tsk->sched_class->moved_group(tsk);
9482 if (unlikely(running))
9483 tsk->sched_class->set_curr_task(rq);
9485 enqueue_task(rq, tsk, 0);
9487 task_rq_unlock(rq, &flags);
9489 #endif /* CONFIG_GROUP_SCHED */
9491 #ifdef CONFIG_FAIR_GROUP_SCHED
9492 static void __set_se_shares(struct sched_entity *se, unsigned long shares)
9494 struct cfs_rq *cfs_rq = se->cfs_rq;
9499 dequeue_entity(cfs_rq, se, 0);
9501 se->load.weight = shares;
9502 se->load.inv_weight = 0;
9505 enqueue_entity(cfs_rq, se, 0);
9508 static void set_se_shares(struct sched_entity *se, unsigned long shares)
9510 struct cfs_rq *cfs_rq = se->cfs_rq;
9511 struct rq *rq = cfs_rq->rq;
9512 unsigned long flags;
9514 spin_lock_irqsave(&rq->lock, flags);
9515 __set_se_shares(se, shares);
9516 spin_unlock_irqrestore(&rq->lock, flags);
9519 static DEFINE_MUTEX(shares_mutex);
9521 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
9524 unsigned long flags;
9527 * We can't change the weight of the root cgroup.
9532 if (shares < MIN_SHARES)
9533 shares = MIN_SHARES;
9534 else if (shares > MAX_SHARES)
9535 shares = MAX_SHARES;
9537 mutex_lock(&shares_mutex);
9538 if (tg->shares == shares)
9541 spin_lock_irqsave(&task_group_lock, flags);
9542 for_each_possible_cpu(i)
9543 unregister_fair_sched_group(tg, i);
9544 list_del_rcu(&tg->siblings);
9545 spin_unlock_irqrestore(&task_group_lock, flags);
9547 /* wait for any ongoing reference to this group to finish */
9548 synchronize_sched();
9551 * Now we are free to modify the group's share on each cpu
9552 * w/o tripping rebalance_share or load_balance_fair.
9554 tg->shares = shares;
9555 for_each_possible_cpu(i) {
9559 cfs_rq_set_shares(tg->cfs_rq[i], 0);
9560 set_se_shares(tg->se[i], shares);
9564 * Enable load balance activity on this group, by inserting it back on
9565 * each cpu's rq->leaf_cfs_rq_list.
9567 spin_lock_irqsave(&task_group_lock, flags);
9568 for_each_possible_cpu(i)
9569 register_fair_sched_group(tg, i);
9570 list_add_rcu(&tg->siblings, &tg->parent->children);
9571 spin_unlock_irqrestore(&task_group_lock, flags);
9573 mutex_unlock(&shares_mutex);
9577 unsigned long sched_group_shares(struct task_group *tg)
9583 #ifdef CONFIG_RT_GROUP_SCHED
9585 * Ensure that the real time constraints are schedulable.
9587 static DEFINE_MUTEX(rt_constraints_mutex);
9589 static unsigned long to_ratio(u64 period, u64 runtime)
9591 if (runtime == RUNTIME_INF)
9594 return div64_u64(runtime << 20, period);
9597 /* Must be called with tasklist_lock held */
9598 static inline int tg_has_rt_tasks(struct task_group *tg)
9600 struct task_struct *g, *p;
9602 do_each_thread(g, p) {
9603 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
9605 } while_each_thread(g, p);
9610 struct rt_schedulable_data {
9611 struct task_group *tg;
9616 static int tg_schedulable(struct task_group *tg, void *data)
9618 struct rt_schedulable_data *d = data;
9619 struct task_group *child;
9620 unsigned long total, sum = 0;
9621 u64 period, runtime;
9623 period = ktime_to_ns(tg->rt_bandwidth.rt_period);
9624 runtime = tg->rt_bandwidth.rt_runtime;
9627 period = d->rt_period;
9628 runtime = d->rt_runtime;
9631 #ifdef CONFIG_USER_SCHED
9632 if (tg == &root_task_group) {
9633 period = global_rt_period();
9634 runtime = global_rt_runtime();
9639 * Cannot have more runtime than the period.
9641 if (runtime > period && runtime != RUNTIME_INF)
9645 * Ensure we don't starve existing RT tasks.
9647 if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
9650 total = to_ratio(period, runtime);
9653 * Nobody can have more than the global setting allows.
9655 if (total > to_ratio(global_rt_period(), global_rt_runtime()))
9659 * The sum of our children's runtime should not exceed our own.
9661 list_for_each_entry_rcu(child, &tg->children, siblings) {
9662 period = ktime_to_ns(child->rt_bandwidth.rt_period);
9663 runtime = child->rt_bandwidth.rt_runtime;
9665 if (child == d->tg) {
9666 period = d->rt_period;
9667 runtime = d->rt_runtime;
9670 sum += to_ratio(period, runtime);
9679 static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
9681 struct rt_schedulable_data data = {
9683 .rt_period = period,
9684 .rt_runtime = runtime,
9687 return walk_tg_tree(tg_schedulable, tg_nop, &data);
9690 static int tg_set_bandwidth(struct task_group *tg,
9691 u64 rt_period, u64 rt_runtime)
9695 mutex_lock(&rt_constraints_mutex);
9696 read_lock(&tasklist_lock);
9697 err = __rt_schedulable(tg, rt_period, rt_runtime);
9701 spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
9702 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
9703 tg->rt_bandwidth.rt_runtime = rt_runtime;
9705 for_each_possible_cpu(i) {
9706 struct rt_rq *rt_rq = tg->rt_rq[i];
9708 spin_lock(&rt_rq->rt_runtime_lock);
9709 rt_rq->rt_runtime = rt_runtime;
9710 spin_unlock(&rt_rq->rt_runtime_lock);
9712 spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
9714 read_unlock(&tasklist_lock);
9715 mutex_unlock(&rt_constraints_mutex);
9720 int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
9722 u64 rt_runtime, rt_period;
9724 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
9725 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
9726 if (rt_runtime_us < 0)
9727 rt_runtime = RUNTIME_INF;
9729 return tg_set_bandwidth(tg, rt_period, rt_runtime);
9732 long sched_group_rt_runtime(struct task_group *tg)
9736 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
9739 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
9740 do_div(rt_runtime_us, NSEC_PER_USEC);
9741 return rt_runtime_us;
9744 int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
9746 u64 rt_runtime, rt_period;
9748 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
9749 rt_runtime = tg->rt_bandwidth.rt_runtime;
9754 return tg_set_bandwidth(tg, rt_period, rt_runtime);
9757 long sched_group_rt_period(struct task_group *tg)
9761 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
9762 do_div(rt_period_us, NSEC_PER_USEC);
9763 return rt_period_us;
9766 static int sched_rt_global_constraints(void)
9768 u64 runtime, period;
9771 if (sysctl_sched_rt_period <= 0)
9774 runtime = global_rt_runtime();
9775 period = global_rt_period();
9778 * Sanity check on the sysctl variables.
9780 if (runtime > period && runtime != RUNTIME_INF)
9783 mutex_lock(&rt_constraints_mutex);
9784 read_lock(&tasklist_lock);
9785 ret = __rt_schedulable(NULL, 0, 0);
9786 read_unlock(&tasklist_lock);
9787 mutex_unlock(&rt_constraints_mutex);
9792 int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
9794 /* Don't accept realtime tasks when there is no way for them to run */
9795 if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
9801 #else /* !CONFIG_RT_GROUP_SCHED */
9802 static int sched_rt_global_constraints(void)
9804 unsigned long flags;
9807 if (sysctl_sched_rt_period <= 0)
9810 spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
9811 for_each_possible_cpu(i) {
9812 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
9814 spin_lock(&rt_rq->rt_runtime_lock);
9815 rt_rq->rt_runtime = global_rt_runtime();
9816 spin_unlock(&rt_rq->rt_runtime_lock);
9818 spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
9822 #endif /* CONFIG_RT_GROUP_SCHED */
9824 int sched_rt_handler(struct ctl_table *table, int write,
9825 struct file *filp, void __user *buffer, size_t *lenp,
9829 int old_period, old_runtime;
9830 static DEFINE_MUTEX(mutex);
9833 old_period = sysctl_sched_rt_period;
9834 old_runtime = sysctl_sched_rt_runtime;
9836 ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
9838 if (!ret && write) {
9839 ret = sched_rt_global_constraints();
9841 sysctl_sched_rt_period = old_period;
9842 sysctl_sched_rt_runtime = old_runtime;
9844 def_rt_bandwidth.rt_runtime = global_rt_runtime();
9845 def_rt_bandwidth.rt_period =
9846 ns_to_ktime(global_rt_period());
9849 mutex_unlock(&mutex);
9854 #ifdef CONFIG_CGROUP_SCHED
9856 /* return corresponding task_group object of a cgroup */
9857 static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
9859 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
9860 struct task_group, css);
9863 static struct cgroup_subsys_state *
9864 cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
9866 struct task_group *tg, *parent;
9868 if (!cgrp->parent) {
9869 /* This is early initialization for the top cgroup */
9870 return &init_task_group.css;
9873 parent = cgroup_tg(cgrp->parent);
9874 tg = sched_create_group(parent);
9876 return ERR_PTR(-ENOMEM);
9882 cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
9884 struct task_group *tg = cgroup_tg(cgrp);
9886 sched_destroy_group(tg);
9890 cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9891 struct task_struct *tsk)
9893 #ifdef CONFIG_RT_GROUP_SCHED
9894 if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
9897 /* We don't support RT-tasks being in separate groups */
9898 if (tsk->sched_class != &fair_sched_class)
9906 cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
9907 struct cgroup *old_cont, struct task_struct *tsk)
9909 sched_move_task(tsk);
9912 #ifdef CONFIG_FAIR_GROUP_SCHED
9913 static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
9916 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
9919 static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
9921 struct task_group *tg = cgroup_tg(cgrp);
9923 return (u64) tg->shares;
9925 #endif /* CONFIG_FAIR_GROUP_SCHED */
9927 #ifdef CONFIG_RT_GROUP_SCHED
9928 static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
9931 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
9934 static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
9936 return sched_group_rt_runtime(cgroup_tg(cgrp));
9939 static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
9942 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
9945 static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
9947 return sched_group_rt_period(cgroup_tg(cgrp));
9949 #endif /* CONFIG_RT_GROUP_SCHED */
9951 static struct cftype cpu_files[] = {
9952 #ifdef CONFIG_FAIR_GROUP_SCHED
9955 .read_u64 = cpu_shares_read_u64,
9956 .write_u64 = cpu_shares_write_u64,
9959 #ifdef CONFIG_RT_GROUP_SCHED
9961 .name = "rt_runtime_us",
9962 .read_s64 = cpu_rt_runtime_read,
9963 .write_s64 = cpu_rt_runtime_write,
9966 .name = "rt_period_us",
9967 .read_u64 = cpu_rt_period_read_uint,
9968 .write_u64 = cpu_rt_period_write_uint,
9973 static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
9975 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
9978 struct cgroup_subsys cpu_cgroup_subsys = {
9980 .create = cpu_cgroup_create,
9981 .destroy = cpu_cgroup_destroy,
9982 .can_attach = cpu_cgroup_can_attach,
9983 .attach = cpu_cgroup_attach,
9984 .populate = cpu_cgroup_populate,
9985 .subsys_id = cpu_cgroup_subsys_id,
9989 #endif /* CONFIG_CGROUP_SCHED */
9991 #ifdef CONFIG_CGROUP_CPUACCT
9994 * CPU accounting code for task groups.
9996 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9997 * (balbir@in.ibm.com).
10000 /* track cpu usage of a group of tasks and its child groups */
10002 struct cgroup_subsys_state css;
10003 /* cpuusage holds pointer to a u64-type object on every cpu */
10005 struct percpu_counter cpustat[CPUACCT_STAT_NSTATS];
10006 struct cpuacct *parent;
10009 struct cgroup_subsys cpuacct_subsys;
10011 /* return cpu accounting group corresponding to this container */
10012 static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
10014 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
10015 struct cpuacct, css);
10018 /* return cpu accounting group to which this task belongs */
10019 static inline struct cpuacct *task_ca(struct task_struct *tsk)
10021 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
10022 struct cpuacct, css);
10025 /* create a new cpu accounting group */
10026 static struct cgroup_subsys_state *cpuacct_create(
10027 struct cgroup_subsys *ss, struct cgroup *cgrp)
10029 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
10035 ca->cpuusage = alloc_percpu(u64);
10039 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
10040 if (percpu_counter_init(&ca->cpustat[i], 0))
10041 goto out_free_counters;
10044 ca->parent = cgroup_ca(cgrp->parent);
10050 percpu_counter_destroy(&ca->cpustat[i]);
10051 free_percpu(ca->cpuusage);
10055 return ERR_PTR(-ENOMEM);
10058 /* destroy an existing cpu accounting group */
10060 cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
10062 struct cpuacct *ca = cgroup_ca(cgrp);
10065 for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
10066 percpu_counter_destroy(&ca->cpustat[i]);
10067 free_percpu(ca->cpuusage);
10071 static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
10073 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10076 #ifndef CONFIG_64BIT
10078 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
10080 spin_lock_irq(&cpu_rq(cpu)->lock);
10082 spin_unlock_irq(&cpu_rq(cpu)->lock);
10090 static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
10092 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10094 #ifndef CONFIG_64BIT
10096 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
10098 spin_lock_irq(&cpu_rq(cpu)->lock);
10100 spin_unlock_irq(&cpu_rq(cpu)->lock);
10106 /* return total cpu usage (in nanoseconds) of a group */
10107 static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
10109 struct cpuacct *ca = cgroup_ca(cgrp);
10110 u64 totalcpuusage = 0;
10113 for_each_present_cpu(i)
10114 totalcpuusage += cpuacct_cpuusage_read(ca, i);
10116 return totalcpuusage;
10119 static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
10122 struct cpuacct *ca = cgroup_ca(cgrp);
10131 for_each_present_cpu(i)
10132 cpuacct_cpuusage_write(ca, i, 0);
10138 static int cpuacct_percpu_seq_read(struct cgroup *cgroup, struct cftype *cft,
10139 struct seq_file *m)
10141 struct cpuacct *ca = cgroup_ca(cgroup);
10145 for_each_present_cpu(i) {
10146 percpu = cpuacct_cpuusage_read(ca, i);
10147 seq_printf(m, "%llu ", (unsigned long long) percpu);
10149 seq_printf(m, "\n");
10153 static const char *cpuacct_stat_desc[] = {
10154 [CPUACCT_STAT_USER] = "user",
10155 [CPUACCT_STAT_SYSTEM] = "system",
10158 static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
10159 struct cgroup_map_cb *cb)
10161 struct cpuacct *ca = cgroup_ca(cgrp);
10164 for (i = 0; i < CPUACCT_STAT_NSTATS; i++) {
10165 s64 val = percpu_counter_read(&ca->cpustat[i]);
10166 val = cputime64_to_clock_t(val);
10167 cb->fill(cb, cpuacct_stat_desc[i], val);
10172 static struct cftype files[] = {
10175 .read_u64 = cpuusage_read,
10176 .write_u64 = cpuusage_write,
10179 .name = "usage_percpu",
10180 .read_seq_string = cpuacct_percpu_seq_read,
10184 .read_map = cpuacct_stats_show,
10188 static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
10190 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
10194 * charge this task's execution time to its accounting group.
10196 * called with rq->lock held.
10198 static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
10200 struct cpuacct *ca;
10203 if (unlikely(!cpuacct_subsys.active))
10206 cpu = task_cpu(tsk);
10212 for (; ca; ca = ca->parent) {
10213 u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
10214 *cpuusage += cputime;
10221 * Charge the system/user time to the task's accounting group.
10223 static void cpuacct_update_stats(struct task_struct *tsk,
10224 enum cpuacct_stat_index idx, cputime_t val)
10226 struct cpuacct *ca;
10228 if (unlikely(!cpuacct_subsys.active))
10235 percpu_counter_add(&ca->cpustat[idx], val);
10241 struct cgroup_subsys cpuacct_subsys = {
10243 .create = cpuacct_create,
10244 .destroy = cpuacct_destroy,
10245 .populate = cpuacct_populate,
10246 .subsys_id = cpuacct_subsys_id,
10248 #endif /* CONFIG_CGROUP_CPUACCT */