4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/kthread.h>
58 #include <linux/proc_fs.h>
59 #include <linux/seq_file.h>
60 #include <linux/sysctl.h>
61 #include <linux/syscalls.h>
62 #include <linux/times.h>
63 #include <linux/tsacct_kern.h>
64 #include <linux/kprobes.h>
65 #include <linux/delayacct.h>
66 #include <linux/reciprocal_div.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/bootmem.h>
72 #include <linux/debugfs.h>
73 #include <linux/ctype.h>
74 #include <linux/ftrace.h>
75 #include <trace/sched.h>
78 #include <asm/irq_regs.h>
80 #include "sched_cpupri.h"
83 * Convert user-nice values [ -20 ... 0 ... 19 ]
84 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
87 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
88 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
89 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
92 * 'User priority' is the nice value converted to something we
93 * can work with better when scaling various scheduler parameters,
94 * it's a [ 0 ... 39 ] range.
96 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
97 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
98 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
101 * Helpers for converting nanosecond timing to jiffy resolution
103 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
105 #define NICE_0_LOAD SCHED_LOAD_SCALE
106 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
109 * These are the 'tuning knobs' of the scheduler:
111 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
112 * Timeslices get refilled after they expire.
114 #define DEF_TIMESLICE (100 * HZ / 1000)
117 * single value that denotes runtime == period, ie unlimited time.
119 #define RUNTIME_INF ((u64)~0ULL)
121 DEFINE_TRACE(sched_wait_task
);
122 DEFINE_TRACE(sched_wakeup
);
123 DEFINE_TRACE(sched_wakeup_new
);
124 DEFINE_TRACE(sched_switch
);
125 DEFINE_TRACE(sched_migrate_task
);
129 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
132 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
133 * Since cpu_power is a 'constant', we can use a reciprocal divide.
135 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
137 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
141 * Each time a sched group cpu_power is changed,
142 * we must compute its reciprocal value
144 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
146 sg
->__cpu_power
+= val
;
147 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
151 static inline int rt_policy(int policy
)
153 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
158 static inline int task_has_rt_policy(struct task_struct
*p
)
160 return rt_policy(p
->policy
);
164 * This is the priority-queue data structure of the RT scheduling class:
166 struct rt_prio_array
{
167 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
168 struct list_head queue
[MAX_RT_PRIO
];
171 struct rt_bandwidth
{
172 /* nests inside the rq lock: */
173 spinlock_t rt_runtime_lock
;
176 struct hrtimer rt_period_timer
;
179 static struct rt_bandwidth def_rt_bandwidth
;
181 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
183 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
185 struct rt_bandwidth
*rt_b
=
186 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
192 now
= hrtimer_cb_get_time(timer
);
193 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
198 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
201 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
205 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
207 rt_b
->rt_period
= ns_to_ktime(period
);
208 rt_b
->rt_runtime
= runtime
;
210 spin_lock_init(&rt_b
->rt_runtime_lock
);
212 hrtimer_init(&rt_b
->rt_period_timer
,
213 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
214 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
217 static inline int rt_bandwidth_enabled(void)
219 return sysctl_sched_rt_runtime
>= 0;
222 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
226 if (rt_bandwidth_enabled() && rt_b
->rt_runtime
== RUNTIME_INF
)
229 if (hrtimer_active(&rt_b
->rt_period_timer
))
232 spin_lock(&rt_b
->rt_runtime_lock
);
234 if (hrtimer_active(&rt_b
->rt_period_timer
))
237 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
238 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
239 hrtimer_start_expires(&rt_b
->rt_period_timer
,
242 spin_unlock(&rt_b
->rt_runtime_lock
);
245 #ifdef CONFIG_RT_GROUP_SCHED
246 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
248 hrtimer_cancel(&rt_b
->rt_period_timer
);
253 * sched_domains_mutex serializes calls to arch_init_sched_domains,
254 * detach_destroy_domains and partition_sched_domains.
256 static DEFINE_MUTEX(sched_domains_mutex
);
258 #ifdef CONFIG_GROUP_SCHED
260 #include <linux/cgroup.h>
264 static LIST_HEAD(task_groups
);
266 /* task group related information */
268 #ifdef CONFIG_CGROUP_SCHED
269 struct cgroup_subsys_state css
;
272 #ifdef CONFIG_USER_SCHED
276 #ifdef CONFIG_FAIR_GROUP_SCHED
277 /* schedulable entities of this group on each cpu */
278 struct sched_entity
**se
;
279 /* runqueue "owned" by this group on each cpu */
280 struct cfs_rq
**cfs_rq
;
281 unsigned long shares
;
284 #ifdef CONFIG_RT_GROUP_SCHED
285 struct sched_rt_entity
**rt_se
;
286 struct rt_rq
**rt_rq
;
288 struct rt_bandwidth rt_bandwidth
;
292 struct list_head list
;
294 struct task_group
*parent
;
295 struct list_head siblings
;
296 struct list_head children
;
299 #ifdef CONFIG_USER_SCHED
301 /* Helper function to pass uid information to create_sched_user() */
302 void set_tg_uid(struct user_struct
*user
)
304 user
->tg
->uid
= user
->uid
;
309 * Every UID task group (including init_task_group aka UID-0) will
310 * be a child to this group.
312 struct task_group root_task_group
;
314 #ifdef CONFIG_FAIR_GROUP_SCHED
315 /* Default task group's sched entity on each cpu */
316 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
317 /* Default task group's cfs_rq on each cpu */
318 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
319 #endif /* CONFIG_FAIR_GROUP_SCHED */
321 #ifdef CONFIG_RT_GROUP_SCHED
322 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
323 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
324 #endif /* CONFIG_RT_GROUP_SCHED */
325 #else /* !CONFIG_USER_SCHED */
326 #define root_task_group init_task_group
327 #endif /* CONFIG_USER_SCHED */
329 /* task_group_lock serializes add/remove of task groups and also changes to
330 * a task group's cpu shares.
332 static DEFINE_SPINLOCK(task_group_lock
);
334 #ifdef CONFIG_FAIR_GROUP_SCHED
335 #ifdef CONFIG_USER_SCHED
336 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
337 #else /* !CONFIG_USER_SCHED */
338 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
339 #endif /* CONFIG_USER_SCHED */
342 * A weight of 0 or 1 can cause arithmetics problems.
343 * A weight of a cfs_rq is the sum of weights of which entities
344 * are queued on this cfs_rq, so a weight of a entity should not be
345 * too large, so as the shares value of a task group.
346 * (The default weight is 1024 - so there's no practical
347 * limitation from this.)
350 #define MAX_SHARES (1UL << 18)
352 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
355 /* Default task group.
356 * Every task in system belong to this group at bootup.
358 struct task_group init_task_group
;
360 /* return group to which a task belongs */
361 static inline struct task_group
*task_group(struct task_struct
*p
)
363 struct task_group
*tg
;
365 #ifdef CONFIG_USER_SCHED
367 tg
= __task_cred(p
)->user
->tg
;
369 #elif defined(CONFIG_CGROUP_SCHED)
370 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
371 struct task_group
, css
);
373 tg
= &init_task_group
;
378 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
379 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
381 #ifdef CONFIG_FAIR_GROUP_SCHED
382 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
383 p
->se
.parent
= task_group(p
)->se
[cpu
];
386 #ifdef CONFIG_RT_GROUP_SCHED
387 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
388 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
394 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
395 static inline struct task_group
*task_group(struct task_struct
*p
)
400 #endif /* CONFIG_GROUP_SCHED */
402 /* CFS-related fields in a runqueue */
404 struct load_weight load
;
405 unsigned long nr_running
;
410 struct rb_root tasks_timeline
;
411 struct rb_node
*rb_leftmost
;
413 struct list_head tasks
;
414 struct list_head
*balance_iterator
;
417 * 'curr' points to currently running entity on this cfs_rq.
418 * It is set to NULL otherwise (i.e when none are currently running).
420 struct sched_entity
*curr
, *next
, *last
;
422 unsigned int nr_spread_over
;
424 #ifdef CONFIG_FAIR_GROUP_SCHED
425 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
428 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
429 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
430 * (like users, containers etc.)
432 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
433 * list is used during load balance.
435 struct list_head leaf_cfs_rq_list
;
436 struct task_group
*tg
; /* group that "owns" this runqueue */
440 * the part of load.weight contributed by tasks
442 unsigned long task_weight
;
445 * h_load = weight * f(tg)
447 * Where f(tg) is the recursive weight fraction assigned to
450 unsigned long h_load
;
453 * this cpu's part of tg->shares
455 unsigned long shares
;
458 * load.weight at the time we set shares
460 unsigned long rq_weight
;
465 /* Real-Time classes' related field in a runqueue: */
467 struct rt_prio_array active
;
468 unsigned long rt_nr_running
;
469 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
471 int curr
; /* highest queued rt task prio */
473 int next
; /* next highest */
478 unsigned long rt_nr_migratory
;
480 struct plist_head pushable_tasks
;
485 /* Nests inside the rq lock: */
486 spinlock_t rt_runtime_lock
;
488 #ifdef CONFIG_RT_GROUP_SCHED
489 unsigned long rt_nr_boosted
;
492 struct list_head leaf_rt_rq_list
;
493 struct task_group
*tg
;
494 struct sched_rt_entity
*rt_se
;
501 * We add the notion of a root-domain which will be used to define per-domain
502 * variables. Each exclusive cpuset essentially defines an island domain by
503 * fully partitioning the member cpus from any other cpuset. Whenever a new
504 * exclusive cpuset is created, we also create and attach a new root-domain
511 cpumask_var_t online
;
514 * The "RT overload" flag: it gets set if a CPU has more than
515 * one runnable RT task.
517 cpumask_var_t rto_mask
;
520 struct cpupri cpupri
;
522 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
524 * Preferred wake up cpu nominated by sched_mc balance that will be
525 * used when most cpus are idle in the system indicating overall very
526 * low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
528 unsigned int sched_mc_preferred_wakeup_cpu
;
533 * By default the system creates a single root-domain with all cpus as
534 * members (mimicking the global state we have today).
536 static struct root_domain def_root_domain
;
541 * This is the main, per-CPU runqueue data structure.
543 * Locking rule: those places that want to lock multiple runqueues
544 * (such as the load balancing or the thread migration code), lock
545 * acquire operations must be ordered by ascending &runqueue.
552 * nr_running and cpu_load should be in the same cacheline because
553 * remote CPUs use both these fields when doing load calculation.
555 unsigned long nr_running
;
556 #define CPU_LOAD_IDX_MAX 5
557 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
558 unsigned char idle_at_tick
;
560 unsigned long last_tick_seen
;
561 unsigned char in_nohz_recently
;
563 /* capture load from *all* tasks on this cpu: */
564 struct load_weight load
;
565 unsigned long nr_load_updates
;
571 #ifdef CONFIG_FAIR_GROUP_SCHED
572 /* list of leaf cfs_rq on this cpu: */
573 struct list_head leaf_cfs_rq_list
;
575 #ifdef CONFIG_RT_GROUP_SCHED
576 struct list_head leaf_rt_rq_list
;
580 * This is part of a global counter where only the total sum
581 * over all CPUs matters. A task can increase this counter on
582 * one CPU and if it got migrated afterwards it may decrease
583 * it on another CPU. Always updated under the runqueue lock:
585 unsigned long nr_uninterruptible
;
587 struct task_struct
*curr
, *idle
;
588 unsigned long next_balance
;
589 struct mm_struct
*prev_mm
;
596 struct root_domain
*rd
;
597 struct sched_domain
*sd
;
599 /* For active balancing */
602 /* cpu of this runqueue: */
606 unsigned long avg_load_per_task
;
608 struct task_struct
*migration_thread
;
609 struct list_head migration_queue
;
612 #ifdef CONFIG_SCHED_HRTICK
614 int hrtick_csd_pending
;
615 struct call_single_data hrtick_csd
;
617 struct hrtimer hrtick_timer
;
620 #ifdef CONFIG_SCHEDSTATS
622 struct sched_info rq_sched_info
;
623 unsigned long long rq_cpu_time
;
624 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
626 /* sys_sched_yield() stats */
627 unsigned int yld_exp_empty
;
628 unsigned int yld_act_empty
;
629 unsigned int yld_both_empty
;
630 unsigned int yld_count
;
632 /* schedule() stats */
633 unsigned int sched_switch
;
634 unsigned int sched_count
;
635 unsigned int sched_goidle
;
637 /* try_to_wake_up() stats */
638 unsigned int ttwu_count
;
639 unsigned int ttwu_local
;
642 unsigned int bkl_count
;
646 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
648 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int sync
)
650 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, sync
);
653 static inline int cpu_of(struct rq
*rq
)
663 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
664 * See detach_destroy_domains: synchronize_sched for details.
666 * The domain tree of any CPU may only be accessed from within
667 * preempt-disabled sections.
669 #define for_each_domain(cpu, __sd) \
670 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
672 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
673 #define this_rq() (&__get_cpu_var(runqueues))
674 #define task_rq(p) cpu_rq(task_cpu(p))
675 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
677 static inline void update_rq_clock(struct rq
*rq
)
679 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
683 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
685 #ifdef CONFIG_SCHED_DEBUG
686 # define const_debug __read_mostly
688 # define const_debug static const
694 * Returns true if the current cpu runqueue is locked.
695 * This interface allows printk to be called with the runqueue lock
696 * held and know whether or not it is OK to wake up the klogd.
698 int runqueue_is_locked(void)
701 struct rq
*rq
= cpu_rq(cpu
);
704 ret
= spin_is_locked(&rq
->lock
);
710 * Debugging: various feature bits
713 #define SCHED_FEAT(name, enabled) \
714 __SCHED_FEAT_##name ,
717 #include "sched_features.h"
722 #define SCHED_FEAT(name, enabled) \
723 (1UL << __SCHED_FEAT_##name) * enabled |
725 const_debug
unsigned int sysctl_sched_features
=
726 #include "sched_features.h"
731 #ifdef CONFIG_SCHED_DEBUG
732 #define SCHED_FEAT(name, enabled) \
735 static __read_mostly
char *sched_feat_names
[] = {
736 #include "sched_features.h"
742 static int sched_feat_show(struct seq_file
*m
, void *v
)
746 for (i
= 0; sched_feat_names
[i
]; i
++) {
747 if (!(sysctl_sched_features
& (1UL << i
)))
749 seq_printf(m
, "%s ", sched_feat_names
[i
]);
757 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
758 size_t cnt
, loff_t
*ppos
)
768 if (copy_from_user(&buf
, ubuf
, cnt
))
773 if (strncmp(buf
, "NO_", 3) == 0) {
778 for (i
= 0; sched_feat_names
[i
]; i
++) {
779 int len
= strlen(sched_feat_names
[i
]);
781 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
783 sysctl_sched_features
&= ~(1UL << i
);
785 sysctl_sched_features
|= (1UL << i
);
790 if (!sched_feat_names
[i
])
798 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
800 return single_open(filp
, sched_feat_show
, NULL
);
803 static struct file_operations sched_feat_fops
= {
804 .open
= sched_feat_open
,
805 .write
= sched_feat_write
,
808 .release
= single_release
,
811 static __init
int sched_init_debug(void)
813 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
818 late_initcall(sched_init_debug
);
822 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
825 * Number of tasks to iterate in a single balance run.
826 * Limited because this is done with IRQs disabled.
828 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
831 * ratelimit for updating the group shares.
834 unsigned int sysctl_sched_shares_ratelimit
= 250000;
837 * Inject some fuzzyness into changing the per-cpu group shares
838 * this avoids remote rq-locks at the expense of fairness.
841 unsigned int sysctl_sched_shares_thresh
= 4;
844 * period over which we measure -rt task cpu usage in us.
847 unsigned int sysctl_sched_rt_period
= 1000000;
849 static __read_mostly
int scheduler_running
;
852 * part of the period that we allow rt tasks to run in us.
855 int sysctl_sched_rt_runtime
= 950000;
857 static inline u64
global_rt_period(void)
859 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
862 static inline u64
global_rt_runtime(void)
864 if (sysctl_sched_rt_runtime
< 0)
867 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
870 #ifndef prepare_arch_switch
871 # define prepare_arch_switch(next) do { } while (0)
873 #ifndef finish_arch_switch
874 # define finish_arch_switch(prev) do { } while (0)
877 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
879 return rq
->curr
== p
;
882 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
883 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
885 return task_current(rq
, p
);
888 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
892 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
894 #ifdef CONFIG_DEBUG_SPINLOCK
895 /* this is a valid case when another task releases the spinlock */
896 rq
->lock
.owner
= current
;
899 * If we are tracking spinlock dependencies then we have to
900 * fix up the runqueue lock - which gets 'carried over' from
903 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
905 spin_unlock_irq(&rq
->lock
);
908 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
909 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
914 return task_current(rq
, p
);
918 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
922 * We can optimise this out completely for !SMP, because the
923 * SMP rebalancing from interrupt is the only thing that cares
928 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
929 spin_unlock_irq(&rq
->lock
);
931 spin_unlock(&rq
->lock
);
935 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
939 * After ->oncpu is cleared, the task can be moved to a different CPU.
940 * We must ensure this doesn't happen until the switch is completely
946 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
950 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
953 * __task_rq_lock - lock the runqueue a given task resides on.
954 * Must be called interrupts disabled.
956 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
960 struct rq
*rq
= task_rq(p
);
961 spin_lock(&rq
->lock
);
962 if (likely(rq
== task_rq(p
)))
964 spin_unlock(&rq
->lock
);
969 * task_rq_lock - lock the runqueue a given task resides on and disable
970 * interrupts. Note the ordering: we can safely lookup the task_rq without
971 * explicitly disabling preemption.
973 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
979 local_irq_save(*flags
);
981 spin_lock(&rq
->lock
);
982 if (likely(rq
== task_rq(p
)))
984 spin_unlock_irqrestore(&rq
->lock
, *flags
);
988 void task_rq_unlock_wait(struct task_struct
*p
)
990 struct rq
*rq
= task_rq(p
);
992 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
993 spin_unlock_wait(&rq
->lock
);
996 static void __task_rq_unlock(struct rq
*rq
)
999 spin_unlock(&rq
->lock
);
1002 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
1003 __releases(rq
->lock
)
1005 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1009 * this_rq_lock - lock this runqueue and disable interrupts.
1011 static struct rq
*this_rq_lock(void)
1012 __acquires(rq
->lock
)
1016 local_irq_disable();
1018 spin_lock(&rq
->lock
);
1023 #ifdef CONFIG_SCHED_HRTICK
1025 * Use HR-timers to deliver accurate preemption points.
1027 * Its all a bit involved since we cannot program an hrt while holding the
1028 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1031 * When we get rescheduled we reprogram the hrtick_timer outside of the
1037 * - enabled by features
1038 * - hrtimer is actually high res
1040 static inline int hrtick_enabled(struct rq
*rq
)
1042 if (!sched_feat(HRTICK
))
1044 if (!cpu_active(cpu_of(rq
)))
1046 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1049 static void hrtick_clear(struct rq
*rq
)
1051 if (hrtimer_active(&rq
->hrtick_timer
))
1052 hrtimer_cancel(&rq
->hrtick_timer
);
1056 * High-resolution timer tick.
1057 * Runs from hardirq context with interrupts disabled.
1059 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1061 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1063 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1065 spin_lock(&rq
->lock
);
1066 update_rq_clock(rq
);
1067 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1068 spin_unlock(&rq
->lock
);
1070 return HRTIMER_NORESTART
;
1075 * called from hardirq (IPI) context
1077 static void __hrtick_start(void *arg
)
1079 struct rq
*rq
= arg
;
1081 spin_lock(&rq
->lock
);
1082 hrtimer_restart(&rq
->hrtick_timer
);
1083 rq
->hrtick_csd_pending
= 0;
1084 spin_unlock(&rq
->lock
);
1088 * Called to set the hrtick timer state.
1090 * called with rq->lock held and irqs disabled
1092 static void hrtick_start(struct rq
*rq
, u64 delay
)
1094 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1095 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1097 hrtimer_set_expires(timer
, time
);
1099 if (rq
== this_rq()) {
1100 hrtimer_restart(timer
);
1101 } else if (!rq
->hrtick_csd_pending
) {
1102 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
);
1103 rq
->hrtick_csd_pending
= 1;
1108 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1110 int cpu
= (int)(long)hcpu
;
1113 case CPU_UP_CANCELED
:
1114 case CPU_UP_CANCELED_FROZEN
:
1115 case CPU_DOWN_PREPARE
:
1116 case CPU_DOWN_PREPARE_FROZEN
:
1118 case CPU_DEAD_FROZEN
:
1119 hrtick_clear(cpu_rq(cpu
));
1126 static __init
void init_hrtick(void)
1128 hotcpu_notifier(hotplug_hrtick
, 0);
1132 * Called to set the hrtick timer state.
1134 * called with rq->lock held and irqs disabled
1136 static void hrtick_start(struct rq
*rq
, u64 delay
)
1138 hrtimer_start(&rq
->hrtick_timer
, ns_to_ktime(delay
), HRTIMER_MODE_REL
);
1141 static inline void init_hrtick(void)
1144 #endif /* CONFIG_SMP */
1146 static void init_rq_hrtick(struct rq
*rq
)
1149 rq
->hrtick_csd_pending
= 0;
1151 rq
->hrtick_csd
.flags
= 0;
1152 rq
->hrtick_csd
.func
= __hrtick_start
;
1153 rq
->hrtick_csd
.info
= rq
;
1156 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1157 rq
->hrtick_timer
.function
= hrtick
;
1159 #else /* CONFIG_SCHED_HRTICK */
1160 static inline void hrtick_clear(struct rq
*rq
)
1164 static inline void init_rq_hrtick(struct rq
*rq
)
1168 static inline void init_hrtick(void)
1171 #endif /* CONFIG_SCHED_HRTICK */
1174 * resched_task - mark a task 'to be rescheduled now'.
1176 * On UP this means the setting of the need_resched flag, on SMP it
1177 * might also involve a cross-CPU call to trigger the scheduler on
1182 #ifndef tsk_is_polling
1183 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1186 static void resched_task(struct task_struct
*p
)
1190 assert_spin_locked(&task_rq(p
)->lock
);
1192 if (unlikely(test_tsk_thread_flag(p
, TIF_NEED_RESCHED
)))
1195 set_tsk_thread_flag(p
, TIF_NEED_RESCHED
);
1198 if (cpu
== smp_processor_id())
1201 /* NEED_RESCHED must be visible before we test polling */
1203 if (!tsk_is_polling(p
))
1204 smp_send_reschedule(cpu
);
1207 static void resched_cpu(int cpu
)
1209 struct rq
*rq
= cpu_rq(cpu
);
1210 unsigned long flags
;
1212 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1214 resched_task(cpu_curr(cpu
));
1215 spin_unlock_irqrestore(&rq
->lock
, flags
);
1220 * When add_timer_on() enqueues a timer into the timer wheel of an
1221 * idle CPU then this timer might expire before the next timer event
1222 * which is scheduled to wake up that CPU. In case of a completely
1223 * idle system the next event might even be infinite time into the
1224 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1225 * leaves the inner idle loop so the newly added timer is taken into
1226 * account when the CPU goes back to idle and evaluates the timer
1227 * wheel for the next timer event.
1229 void wake_up_idle_cpu(int cpu
)
1231 struct rq
*rq
= cpu_rq(cpu
);
1233 if (cpu
== smp_processor_id())
1237 * This is safe, as this function is called with the timer
1238 * wheel base lock of (cpu) held. When the CPU is on the way
1239 * to idle and has not yet set rq->curr to idle then it will
1240 * be serialized on the timer wheel base lock and take the new
1241 * timer into account automatically.
1243 if (rq
->curr
!= rq
->idle
)
1247 * We can set TIF_RESCHED on the idle task of the other CPU
1248 * lockless. The worst case is that the other CPU runs the
1249 * idle task through an additional NOOP schedule()
1251 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1253 /* NEED_RESCHED must be visible before we test polling */
1255 if (!tsk_is_polling(rq
->idle
))
1256 smp_send_reschedule(cpu
);
1258 #endif /* CONFIG_NO_HZ */
1260 #else /* !CONFIG_SMP */
1261 static void resched_task(struct task_struct
*p
)
1263 assert_spin_locked(&task_rq(p
)->lock
);
1264 set_tsk_need_resched(p
);
1266 #endif /* CONFIG_SMP */
1268 #if BITS_PER_LONG == 32
1269 # define WMULT_CONST (~0UL)
1271 # define WMULT_CONST (1UL << 32)
1274 #define WMULT_SHIFT 32
1277 * Shift right and round:
1279 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1282 * delta *= weight / lw
1284 static unsigned long
1285 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1286 struct load_weight
*lw
)
1290 if (!lw
->inv_weight
) {
1291 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1294 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1298 tmp
= (u64
)delta_exec
* weight
;
1300 * Check whether we'd overflow the 64-bit multiplication:
1302 if (unlikely(tmp
> WMULT_CONST
))
1303 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1306 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1308 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1311 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1317 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1324 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1325 * of tasks with abnormal "nice" values across CPUs the contribution that
1326 * each task makes to its run queue's load is weighted according to its
1327 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1328 * scaled version of the new time slice allocation that they receive on time
1332 #define WEIGHT_IDLEPRIO 3
1333 #define WMULT_IDLEPRIO 1431655765
1336 * Nice levels are multiplicative, with a gentle 10% change for every
1337 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1338 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1339 * that remained on nice 0.
1341 * The "10% effect" is relative and cumulative: from _any_ nice level,
1342 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1343 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1344 * If a task goes up by ~10% and another task goes down by ~10% then
1345 * the relative distance between them is ~25%.)
1347 static const int prio_to_weight
[40] = {
1348 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1349 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1350 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1351 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1352 /* 0 */ 1024, 820, 655, 526, 423,
1353 /* 5 */ 335, 272, 215, 172, 137,
1354 /* 10 */ 110, 87, 70, 56, 45,
1355 /* 15 */ 36, 29, 23, 18, 15,
1359 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1361 * In cases where the weight does not change often, we can use the
1362 * precalculated inverse to speed up arithmetics by turning divisions
1363 * into multiplications:
1365 static const u32 prio_to_wmult
[40] = {
1366 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1367 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1368 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1369 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1370 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1371 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1372 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1373 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1376 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1379 * runqueue iterator, to support SMP load-balancing between different
1380 * scheduling classes, without having to expose their internal data
1381 * structures to the load-balancing proper:
1383 struct rq_iterator
{
1385 struct task_struct
*(*start
)(void *);
1386 struct task_struct
*(*next
)(void *);
1390 static unsigned long
1391 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1392 unsigned long max_load_move
, struct sched_domain
*sd
,
1393 enum cpu_idle_type idle
, int *all_pinned
,
1394 int *this_best_prio
, struct rq_iterator
*iterator
);
1397 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1398 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1399 struct rq_iterator
*iterator
);
1402 #ifdef CONFIG_CGROUP_CPUACCT
1403 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1405 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1408 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1410 update_load_add(&rq
->load
, load
);
1413 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1415 update_load_sub(&rq
->load
, load
);
1418 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1419 typedef int (*tg_visitor
)(struct task_group
*, void *);
1422 * Iterate the full tree, calling @down when first entering a node and @up when
1423 * leaving it for the final time.
1425 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1427 struct task_group
*parent
, *child
;
1431 parent
= &root_task_group
;
1433 ret
= (*down
)(parent
, data
);
1436 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1443 ret
= (*up
)(parent
, data
);
1448 parent
= parent
->parent
;
1457 static int tg_nop(struct task_group
*tg
, void *data
)
1464 static unsigned long source_load(int cpu
, int type
);
1465 static unsigned long target_load(int cpu
, int type
);
1466 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1468 static unsigned long cpu_avg_load_per_task(int cpu
)
1470 struct rq
*rq
= cpu_rq(cpu
);
1471 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1474 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1476 rq
->avg_load_per_task
= 0;
1478 return rq
->avg_load_per_task
;
1481 #ifdef CONFIG_FAIR_GROUP_SCHED
1483 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1486 * Calculate and set the cpu's group shares.
1489 update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1490 unsigned long sd_shares
, unsigned long sd_rq_weight
)
1492 unsigned long shares
;
1493 unsigned long rq_weight
;
1498 rq_weight
= tg
->cfs_rq
[cpu
]->rq_weight
;
1501 * \Sum shares * rq_weight
1502 * shares = -----------------------
1506 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1507 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1509 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1510 sysctl_sched_shares_thresh
) {
1511 struct rq
*rq
= cpu_rq(cpu
);
1512 unsigned long flags
;
1514 spin_lock_irqsave(&rq
->lock
, flags
);
1515 tg
->cfs_rq
[cpu
]->shares
= shares
;
1517 __set_se_shares(tg
->se
[cpu
], shares
);
1518 spin_unlock_irqrestore(&rq
->lock
, flags
);
1523 * Re-compute the task group their per cpu shares over the given domain.
1524 * This needs to be done in a bottom-up fashion because the rq weight of a
1525 * parent group depends on the shares of its child groups.
1527 static int tg_shares_up(struct task_group
*tg
, void *data
)
1529 unsigned long weight
, rq_weight
= 0;
1530 unsigned long shares
= 0;
1531 struct sched_domain
*sd
= data
;
1534 for_each_cpu(i
, sched_domain_span(sd
)) {
1536 * If there are currently no tasks on the cpu pretend there
1537 * is one of average load so that when a new task gets to
1538 * run here it will not get delayed by group starvation.
1540 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1542 weight
= NICE_0_LOAD
;
1544 tg
->cfs_rq
[i
]->rq_weight
= weight
;
1545 rq_weight
+= weight
;
1546 shares
+= tg
->cfs_rq
[i
]->shares
;
1549 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1550 shares
= tg
->shares
;
1552 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1553 shares
= tg
->shares
;
1555 for_each_cpu(i
, sched_domain_span(sd
))
1556 update_group_shares_cpu(tg
, i
, shares
, rq_weight
);
1562 * Compute the cpu's hierarchical load factor for each task group.
1563 * This needs to be done in a top-down fashion because the load of a child
1564 * group is a fraction of its parents load.
1566 static int tg_load_down(struct task_group
*tg
, void *data
)
1569 long cpu
= (long)data
;
1572 load
= cpu_rq(cpu
)->load
.weight
;
1574 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1575 load
*= tg
->cfs_rq
[cpu
]->shares
;
1576 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1579 tg
->cfs_rq
[cpu
]->h_load
= load
;
1584 static void update_shares(struct sched_domain
*sd
)
1586 u64 now
= cpu_clock(raw_smp_processor_id());
1587 s64 elapsed
= now
- sd
->last_update
;
1589 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1590 sd
->last_update
= now
;
1591 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1595 static void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1597 spin_unlock(&rq
->lock
);
1599 spin_lock(&rq
->lock
);
1602 static void update_h_load(long cpu
)
1604 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1609 static inline void update_shares(struct sched_domain
*sd
)
1613 static inline void update_shares_locked(struct rq
*rq
, struct sched_domain
*sd
)
1619 #ifdef CONFIG_PREEMPT
1622 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1623 * way at the expense of forcing extra atomic operations in all
1624 * invocations. This assures that the double_lock is acquired using the
1625 * same underlying policy as the spinlock_t on this architecture, which
1626 * reduces latency compared to the unfair variant below. However, it
1627 * also adds more overhead and therefore may reduce throughput.
1629 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1630 __releases(this_rq
->lock
)
1631 __acquires(busiest
->lock
)
1632 __acquires(this_rq
->lock
)
1634 spin_unlock(&this_rq
->lock
);
1635 double_rq_lock(this_rq
, busiest
);
1642 * Unfair double_lock_balance: Optimizes throughput at the expense of
1643 * latency by eliminating extra atomic operations when the locks are
1644 * already in proper order on entry. This favors lower cpu-ids and will
1645 * grant the double lock to lower cpus over higher ids under contention,
1646 * regardless of entry order into the function.
1648 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1649 __releases(this_rq
->lock
)
1650 __acquires(busiest
->lock
)
1651 __acquires(this_rq
->lock
)
1655 if (unlikely(!spin_trylock(&busiest
->lock
))) {
1656 if (busiest
< this_rq
) {
1657 spin_unlock(&this_rq
->lock
);
1658 spin_lock(&busiest
->lock
);
1659 spin_lock_nested(&this_rq
->lock
, SINGLE_DEPTH_NESTING
);
1662 spin_lock_nested(&busiest
->lock
, SINGLE_DEPTH_NESTING
);
1667 #endif /* CONFIG_PREEMPT */
1670 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1672 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1674 if (unlikely(!irqs_disabled())) {
1675 /* printk() doesn't work good under rq->lock */
1676 spin_unlock(&this_rq
->lock
);
1680 return _double_lock_balance(this_rq
, busiest
);
1683 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1684 __releases(busiest
->lock
)
1686 spin_unlock(&busiest
->lock
);
1687 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1691 #ifdef CONFIG_FAIR_GROUP_SCHED
1692 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1695 cfs_rq
->shares
= shares
;
1700 #include "sched_stats.h"
1701 #include "sched_idletask.c"
1702 #include "sched_fair.c"
1703 #include "sched_rt.c"
1704 #ifdef CONFIG_SCHED_DEBUG
1705 # include "sched_debug.c"
1708 #define sched_class_highest (&rt_sched_class)
1709 #define for_each_class(class) \
1710 for (class = sched_class_highest; class; class = class->next)
1712 static void inc_nr_running(struct rq
*rq
)
1717 static void dec_nr_running(struct rq
*rq
)
1722 static void set_load_weight(struct task_struct
*p
)
1724 if (task_has_rt_policy(p
)) {
1725 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1726 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1731 * SCHED_IDLE tasks get minimal weight:
1733 if (p
->policy
== SCHED_IDLE
) {
1734 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1735 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1739 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1740 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1743 static void update_avg(u64
*avg
, u64 sample
)
1745 s64 diff
= sample
- *avg
;
1749 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1752 p
->se
.start_runtime
= p
->se
.sum_exec_runtime
;
1754 sched_info_queued(p
);
1755 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1759 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1762 if (p
->se
.last_wakeup
) {
1763 update_avg(&p
->se
.avg_overlap
,
1764 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1765 p
->se
.last_wakeup
= 0;
1767 update_avg(&p
->se
.avg_wakeup
,
1768 sysctl_sched_wakeup_granularity
);
1772 sched_info_dequeued(p
);
1773 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1778 * __normal_prio - return the priority that is based on the static prio
1780 static inline int __normal_prio(struct task_struct
*p
)
1782 return p
->static_prio
;
1786 * Calculate the expected normal priority: i.e. priority
1787 * without taking RT-inheritance into account. Might be
1788 * boosted by interactivity modifiers. Changes upon fork,
1789 * setprio syscalls, and whenever the interactivity
1790 * estimator recalculates.
1792 static inline int normal_prio(struct task_struct
*p
)
1796 if (task_has_rt_policy(p
))
1797 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1799 prio
= __normal_prio(p
);
1804 * Calculate the current priority, i.e. the priority
1805 * taken into account by the scheduler. This value might
1806 * be boosted by RT tasks, or might be boosted by
1807 * interactivity modifiers. Will be RT if the task got
1808 * RT-boosted. If not then it returns p->normal_prio.
1810 static int effective_prio(struct task_struct
*p
)
1812 p
->normal_prio
= normal_prio(p
);
1814 * If we are RT tasks or we were boosted to RT priority,
1815 * keep the priority unchanged. Otherwise, update priority
1816 * to the normal priority:
1818 if (!rt_prio(p
->prio
))
1819 return p
->normal_prio
;
1824 * activate_task - move a task to the runqueue.
1826 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1828 if (task_contributes_to_load(p
))
1829 rq
->nr_uninterruptible
--;
1831 enqueue_task(rq
, p
, wakeup
);
1836 * deactivate_task - remove a task from the runqueue.
1838 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1840 if (task_contributes_to_load(p
))
1841 rq
->nr_uninterruptible
++;
1843 dequeue_task(rq
, p
, sleep
);
1848 * task_curr - is this task currently executing on a CPU?
1849 * @p: the task in question.
1851 inline int task_curr(const struct task_struct
*p
)
1853 return cpu_curr(task_cpu(p
)) == p
;
1856 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1858 set_task_rq(p
, cpu
);
1861 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1862 * successfuly executed on another CPU. We must ensure that updates of
1863 * per-task data have been completed by this moment.
1866 task_thread_info(p
)->cpu
= cpu
;
1870 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1871 const struct sched_class
*prev_class
,
1872 int oldprio
, int running
)
1874 if (prev_class
!= p
->sched_class
) {
1875 if (prev_class
->switched_from
)
1876 prev_class
->switched_from(rq
, p
, running
);
1877 p
->sched_class
->switched_to(rq
, p
, running
);
1879 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1884 /* Used instead of source_load when we know the type == 0 */
1885 static unsigned long weighted_cpuload(const int cpu
)
1887 return cpu_rq(cpu
)->load
.weight
;
1891 * Is this task likely cache-hot:
1894 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1899 * Buddy candidates are cache hot:
1901 if (sched_feat(CACHE_HOT_BUDDY
) &&
1902 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
1903 &p
->se
== cfs_rq_of(&p
->se
)->last
))
1906 if (p
->sched_class
!= &fair_sched_class
)
1909 if (sysctl_sched_migration_cost
== -1)
1911 if (sysctl_sched_migration_cost
== 0)
1914 delta
= now
- p
->se
.exec_start
;
1916 return delta
< (s64
)sysctl_sched_migration_cost
;
1920 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1922 int old_cpu
= task_cpu(p
);
1923 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1924 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1925 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1928 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1930 trace_sched_migrate_task(p
, task_cpu(p
), new_cpu
);
1932 #ifdef CONFIG_SCHEDSTATS
1933 if (p
->se
.wait_start
)
1934 p
->se
.wait_start
-= clock_offset
;
1935 if (p
->se
.sleep_start
)
1936 p
->se
.sleep_start
-= clock_offset
;
1937 if (p
->se
.block_start
)
1938 p
->se
.block_start
-= clock_offset
;
1939 if (old_cpu
!= new_cpu
) {
1940 schedstat_inc(p
, se
.nr_migrations
);
1941 if (task_hot(p
, old_rq
->clock
, NULL
))
1942 schedstat_inc(p
, se
.nr_forced2_migrations
);
1945 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1946 new_cfsrq
->min_vruntime
;
1948 __set_task_cpu(p
, new_cpu
);
1951 struct migration_req
{
1952 struct list_head list
;
1954 struct task_struct
*task
;
1957 struct completion done
;
1961 * The task's runqueue lock must be held.
1962 * Returns true if you have to wait for migration thread.
1965 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1967 struct rq
*rq
= task_rq(p
);
1970 * If the task is not on a runqueue (and not running), then
1971 * it is sufficient to simply update the task's cpu field.
1973 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1974 set_task_cpu(p
, dest_cpu
);
1978 init_completion(&req
->done
);
1980 req
->dest_cpu
= dest_cpu
;
1981 list_add(&req
->list
, &rq
->migration_queue
);
1987 * wait_task_inactive - wait for a thread to unschedule.
1989 * If @match_state is nonzero, it's the @p->state value just checked and
1990 * not expected to change. If it changes, i.e. @p might have woken up,
1991 * then return zero. When we succeed in waiting for @p to be off its CPU,
1992 * we return a positive number (its total switch count). If a second call
1993 * a short while later returns the same number, the caller can be sure that
1994 * @p has remained unscheduled the whole time.
1996 * The caller must ensure that the task *will* unschedule sometime soon,
1997 * else this function might spin for a *long* time. This function can't
1998 * be called with interrupts off, or it may introduce deadlock with
1999 * smp_call_function() if an IPI is sent by the same process we are
2000 * waiting to become inactive.
2002 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2004 unsigned long flags
;
2011 * We do the initial early heuristics without holding
2012 * any task-queue locks at all. We'll only try to get
2013 * the runqueue lock when things look like they will
2019 * If the task is actively running on another CPU
2020 * still, just relax and busy-wait without holding
2023 * NOTE! Since we don't hold any locks, it's not
2024 * even sure that "rq" stays as the right runqueue!
2025 * But we don't care, since "task_running()" will
2026 * return false if the runqueue has changed and p
2027 * is actually now running somewhere else!
2029 while (task_running(rq
, p
)) {
2030 if (match_state
&& unlikely(p
->state
!= match_state
))
2036 * Ok, time to look more closely! We need the rq
2037 * lock now, to be *sure*. If we're wrong, we'll
2038 * just go back and repeat.
2040 rq
= task_rq_lock(p
, &flags
);
2041 trace_sched_wait_task(rq
, p
);
2042 running
= task_running(rq
, p
);
2043 on_rq
= p
->se
.on_rq
;
2045 if (!match_state
|| p
->state
== match_state
)
2046 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2047 task_rq_unlock(rq
, &flags
);
2050 * If it changed from the expected state, bail out now.
2052 if (unlikely(!ncsw
))
2056 * Was it really running after all now that we
2057 * checked with the proper locks actually held?
2059 * Oops. Go back and try again..
2061 if (unlikely(running
)) {
2067 * It's not enough that it's not actively running,
2068 * it must be off the runqueue _entirely_, and not
2071 * So if it wa still runnable (but just not actively
2072 * running right now), it's preempted, and we should
2073 * yield - it could be a while.
2075 if (unlikely(on_rq
)) {
2076 schedule_timeout_uninterruptible(1);
2081 * Ahh, all good. It wasn't running, and it wasn't
2082 * runnable, which means that it will never become
2083 * running in the future either. We're all done!
2092 * kick_process - kick a running thread to enter/exit the kernel
2093 * @p: the to-be-kicked thread
2095 * Cause a process which is running on another CPU to enter
2096 * kernel-mode, without any delay. (to get signals handled.)
2098 * NOTE: this function doesnt have to take the runqueue lock,
2099 * because all it wants to ensure is that the remote task enters
2100 * the kernel. If the IPI races and the task has been migrated
2101 * to another CPU then no harm is done and the purpose has been
2104 void kick_process(struct task_struct
*p
)
2110 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2111 smp_send_reschedule(cpu
);
2116 * Return a low guess at the load of a migration-source cpu weighted
2117 * according to the scheduling class and "nice" value.
2119 * We want to under-estimate the load of migration sources, to
2120 * balance conservatively.
2122 static unsigned long source_load(int cpu
, int type
)
2124 struct rq
*rq
= cpu_rq(cpu
);
2125 unsigned long total
= weighted_cpuload(cpu
);
2127 if (type
== 0 || !sched_feat(LB_BIAS
))
2130 return min(rq
->cpu_load
[type
-1], total
);
2134 * Return a high guess at the load of a migration-target cpu weighted
2135 * according to the scheduling class and "nice" value.
2137 static unsigned long target_load(int cpu
, int type
)
2139 struct rq
*rq
= cpu_rq(cpu
);
2140 unsigned long total
= weighted_cpuload(cpu
);
2142 if (type
== 0 || !sched_feat(LB_BIAS
))
2145 return max(rq
->cpu_load
[type
-1], total
);
2149 * find_idlest_group finds and returns the least busy CPU group within the
2152 static struct sched_group
*
2153 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
2155 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2156 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
2157 int load_idx
= sd
->forkexec_idx
;
2158 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
2161 unsigned long load
, avg_load
;
2165 /* Skip over this group if it has no CPUs allowed */
2166 if (!cpumask_intersects(sched_group_cpus(group
),
2170 local_group
= cpumask_test_cpu(this_cpu
,
2171 sched_group_cpus(group
));
2173 /* Tally up the load of all CPUs in the group */
2176 for_each_cpu(i
, sched_group_cpus(group
)) {
2177 /* Bias balancing toward cpus of our domain */
2179 load
= source_load(i
, load_idx
);
2181 load
= target_load(i
, load_idx
);
2186 /* Adjust by relative CPU power of the group */
2187 avg_load
= sg_div_cpu_power(group
,
2188 avg_load
* SCHED_LOAD_SCALE
);
2191 this_load
= avg_load
;
2193 } else if (avg_load
< min_load
) {
2194 min_load
= avg_load
;
2197 } while (group
= group
->next
, group
!= sd
->groups
);
2199 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
2205 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2208 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
)
2210 unsigned long load
, min_load
= ULONG_MAX
;
2214 /* Traverse only the allowed CPUs */
2215 for_each_cpu_and(i
, sched_group_cpus(group
), &p
->cpus_allowed
) {
2216 load
= weighted_cpuload(i
);
2218 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
2228 * sched_balance_self: balance the current task (running on cpu) in domains
2229 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2232 * Balance, ie. select the least loaded group.
2234 * Returns the target CPU number, or the same CPU if no balancing is needed.
2236 * preempt must be disabled.
2238 static int sched_balance_self(int cpu
, int flag
)
2240 struct task_struct
*t
= current
;
2241 struct sched_domain
*tmp
, *sd
= NULL
;
2243 for_each_domain(cpu
, tmp
) {
2245 * If power savings logic is enabled for a domain, stop there.
2247 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2249 if (tmp
->flags
& flag
)
2257 struct sched_group
*group
;
2258 int new_cpu
, weight
;
2260 if (!(sd
->flags
& flag
)) {
2265 group
= find_idlest_group(sd
, t
, cpu
);
2271 new_cpu
= find_idlest_cpu(group
, t
, cpu
);
2272 if (new_cpu
== -1 || new_cpu
== cpu
) {
2273 /* Now try balancing at a lower domain level of cpu */
2278 /* Now try balancing at a lower domain level of new_cpu */
2280 weight
= cpumask_weight(sched_domain_span(sd
));
2282 for_each_domain(cpu
, tmp
) {
2283 if (weight
<= cpumask_weight(sched_domain_span(tmp
)))
2285 if (tmp
->flags
& flag
)
2288 /* while loop will break here if sd == NULL */
2294 #endif /* CONFIG_SMP */
2297 * try_to_wake_up - wake up a thread
2298 * @p: the to-be-woken-up thread
2299 * @state: the mask of task states that can be woken
2300 * @sync: do a synchronous wakeup?
2302 * Put it on the run-queue if it's not already there. The "current"
2303 * thread is always on the run-queue (except when the actual
2304 * re-schedule is in progress), and as such you're allowed to do
2305 * the simpler "current->state = TASK_RUNNING" to mark yourself
2306 * runnable without the overhead of this.
2308 * returns failure only if the task is already active.
2310 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2312 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2313 unsigned long flags
;
2317 if (!sched_feat(SYNC_WAKEUPS
))
2321 if (current
->se
.avg_overlap
< sysctl_sched_migration_cost
&&
2322 p
->se
.avg_overlap
< sysctl_sched_migration_cost
)
2325 if (current
->se
.avg_overlap
>= sysctl_sched_migration_cost
||
2326 p
->se
.avg_overlap
>= sysctl_sched_migration_cost
)
2331 if (sched_feat(LB_WAKEUP_UPDATE
)) {
2332 struct sched_domain
*sd
;
2334 this_cpu
= raw_smp_processor_id();
2337 for_each_domain(this_cpu
, sd
) {
2338 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2347 rq
= task_rq_lock(p
, &flags
);
2348 update_rq_clock(rq
);
2349 old_state
= p
->state
;
2350 if (!(old_state
& state
))
2358 this_cpu
= smp_processor_id();
2361 if (unlikely(task_running(rq
, p
)))
2364 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2365 if (cpu
!= orig_cpu
) {
2366 set_task_cpu(p
, cpu
);
2367 task_rq_unlock(rq
, &flags
);
2368 /* might preempt at this point */
2369 rq
= task_rq_lock(p
, &flags
);
2370 old_state
= p
->state
;
2371 if (!(old_state
& state
))
2376 this_cpu
= smp_processor_id();
2380 #ifdef CONFIG_SCHEDSTATS
2381 schedstat_inc(rq
, ttwu_count
);
2382 if (cpu
== this_cpu
)
2383 schedstat_inc(rq
, ttwu_local
);
2385 struct sched_domain
*sd
;
2386 for_each_domain(this_cpu
, sd
) {
2387 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2388 schedstat_inc(sd
, ttwu_wake_remote
);
2393 #endif /* CONFIG_SCHEDSTATS */
2396 #endif /* CONFIG_SMP */
2397 schedstat_inc(p
, se
.nr_wakeups
);
2399 schedstat_inc(p
, se
.nr_wakeups_sync
);
2400 if (orig_cpu
!= cpu
)
2401 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2402 if (cpu
== this_cpu
)
2403 schedstat_inc(p
, se
.nr_wakeups_local
);
2405 schedstat_inc(p
, se
.nr_wakeups_remote
);
2406 activate_task(rq
, p
, 1);
2410 * Only attribute actual wakeups done by this task.
2412 if (!in_interrupt()) {
2413 struct sched_entity
*se
= ¤t
->se
;
2414 u64 sample
= se
->sum_exec_runtime
;
2416 if (se
->last_wakeup
)
2417 sample
-= se
->last_wakeup
;
2419 sample
-= se
->start_runtime
;
2420 update_avg(&se
->avg_wakeup
, sample
);
2422 se
->last_wakeup
= se
->sum_exec_runtime
;
2426 trace_sched_wakeup(rq
, p
, success
);
2427 check_preempt_curr(rq
, p
, sync
);
2429 p
->state
= TASK_RUNNING
;
2431 if (p
->sched_class
->task_wake_up
)
2432 p
->sched_class
->task_wake_up(rq
, p
);
2435 task_rq_unlock(rq
, &flags
);
2440 int wake_up_process(struct task_struct
*p
)
2442 return try_to_wake_up(p
, TASK_ALL
, 0);
2444 EXPORT_SYMBOL(wake_up_process
);
2446 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2448 return try_to_wake_up(p
, state
, 0);
2452 * Perform scheduler related setup for a newly forked process p.
2453 * p is forked by current.
2455 * __sched_fork() is basic setup used by init_idle() too:
2457 static void __sched_fork(struct task_struct
*p
)
2459 p
->se
.exec_start
= 0;
2460 p
->se
.sum_exec_runtime
= 0;
2461 p
->se
.prev_sum_exec_runtime
= 0;
2462 p
->se
.last_wakeup
= 0;
2463 p
->se
.avg_overlap
= 0;
2464 p
->se
.start_runtime
= 0;
2465 p
->se
.avg_wakeup
= sysctl_sched_wakeup_granularity
;
2467 #ifdef CONFIG_SCHEDSTATS
2468 p
->se
.wait_start
= 0;
2469 p
->se
.sum_sleep_runtime
= 0;
2470 p
->se
.sleep_start
= 0;
2471 p
->se
.block_start
= 0;
2472 p
->se
.sleep_max
= 0;
2473 p
->se
.block_max
= 0;
2475 p
->se
.slice_max
= 0;
2479 INIT_LIST_HEAD(&p
->rt
.run_list
);
2481 INIT_LIST_HEAD(&p
->se
.group_node
);
2483 #ifdef CONFIG_PREEMPT_NOTIFIERS
2484 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2488 * We mark the process as running here, but have not actually
2489 * inserted it onto the runqueue yet. This guarantees that
2490 * nobody will actually run it, and a signal or other external
2491 * event cannot wake it up and insert it on the runqueue either.
2493 p
->state
= TASK_RUNNING
;
2497 * fork()/clone()-time setup:
2499 void sched_fork(struct task_struct
*p
, int clone_flags
)
2501 int cpu
= get_cpu();
2506 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2508 set_task_cpu(p
, cpu
);
2511 * Make sure we do not leak PI boosting priority to the child:
2513 p
->prio
= current
->normal_prio
;
2514 if (!rt_prio(p
->prio
))
2515 p
->sched_class
= &fair_sched_class
;
2517 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2518 if (likely(sched_info_on()))
2519 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2521 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2524 #ifdef CONFIG_PREEMPT
2525 /* Want to start with kernel preemption disabled. */
2526 task_thread_info(p
)->preempt_count
= 1;
2528 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2534 * wake_up_new_task - wake up a newly created task for the first time.
2536 * This function will do some initial scheduler statistics housekeeping
2537 * that must be done for every newly created context, then puts the task
2538 * on the runqueue and wakes it.
2540 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2542 unsigned long flags
;
2545 rq
= task_rq_lock(p
, &flags
);
2546 BUG_ON(p
->state
!= TASK_RUNNING
);
2547 update_rq_clock(rq
);
2549 p
->prio
= effective_prio(p
);
2551 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2552 activate_task(rq
, p
, 0);
2555 * Let the scheduling class do new task startup
2556 * management (if any):
2558 p
->sched_class
->task_new(rq
, p
);
2561 trace_sched_wakeup_new(rq
, p
, 1);
2562 check_preempt_curr(rq
, p
, 0);
2564 if (p
->sched_class
->task_wake_up
)
2565 p
->sched_class
->task_wake_up(rq
, p
);
2567 task_rq_unlock(rq
, &flags
);
2570 #ifdef CONFIG_PREEMPT_NOTIFIERS
2573 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2574 * @notifier: notifier struct to register
2576 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2578 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2580 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2583 * preempt_notifier_unregister - no longer interested in preemption notifications
2584 * @notifier: notifier struct to unregister
2586 * This is safe to call from within a preemption notifier.
2588 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2590 hlist_del(¬ifier
->link
);
2592 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2594 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2596 struct preempt_notifier
*notifier
;
2597 struct hlist_node
*node
;
2599 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2600 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2604 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2605 struct task_struct
*next
)
2607 struct preempt_notifier
*notifier
;
2608 struct hlist_node
*node
;
2610 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2611 notifier
->ops
->sched_out(notifier
, next
);
2614 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2616 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2621 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2622 struct task_struct
*next
)
2626 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2629 * prepare_task_switch - prepare to switch tasks
2630 * @rq: the runqueue preparing to switch
2631 * @prev: the current task that is being switched out
2632 * @next: the task we are going to switch to.
2634 * This is called with the rq lock held and interrupts off. It must
2635 * be paired with a subsequent finish_task_switch after the context
2638 * prepare_task_switch sets up locking and calls architecture specific
2642 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2643 struct task_struct
*next
)
2645 fire_sched_out_preempt_notifiers(prev
, next
);
2646 prepare_lock_switch(rq
, next
);
2647 prepare_arch_switch(next
);
2651 * finish_task_switch - clean up after a task-switch
2652 * @rq: runqueue associated with task-switch
2653 * @prev: the thread we just switched away from.
2655 * finish_task_switch must be called after the context switch, paired
2656 * with a prepare_task_switch call before the context switch.
2657 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2658 * and do any other architecture-specific cleanup actions.
2660 * Note that we may have delayed dropping an mm in context_switch(). If
2661 * so, we finish that here outside of the runqueue lock. (Doing it
2662 * with the lock held can cause deadlocks; see schedule() for
2665 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2666 __releases(rq
->lock
)
2668 struct mm_struct
*mm
= rq
->prev_mm
;
2671 int post_schedule
= 0;
2673 if (current
->sched_class
->needs_post_schedule
)
2674 post_schedule
= current
->sched_class
->needs_post_schedule(rq
);
2680 * A task struct has one reference for the use as "current".
2681 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2682 * schedule one last time. The schedule call will never return, and
2683 * the scheduled task must drop that reference.
2684 * The test for TASK_DEAD must occur while the runqueue locks are
2685 * still held, otherwise prev could be scheduled on another cpu, die
2686 * there before we look at prev->state, and then the reference would
2688 * Manfred Spraul <manfred@colorfullife.com>
2690 prev_state
= prev
->state
;
2691 finish_arch_switch(prev
);
2692 finish_lock_switch(rq
, prev
);
2695 current
->sched_class
->post_schedule(rq
);
2698 fire_sched_in_preempt_notifiers(current
);
2701 if (unlikely(prev_state
== TASK_DEAD
)) {
2703 * Remove function-return probe instances associated with this
2704 * task and put them back on the free list.
2706 kprobe_flush_task(prev
);
2707 put_task_struct(prev
);
2712 * schedule_tail - first thing a freshly forked thread must call.
2713 * @prev: the thread we just switched away from.
2715 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2716 __releases(rq
->lock
)
2718 struct rq
*rq
= this_rq();
2720 finish_task_switch(rq
, prev
);
2721 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2722 /* In this case, finish_task_switch does not reenable preemption */
2725 if (current
->set_child_tid
)
2726 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2730 * context_switch - switch to the new MM and the new
2731 * thread's register state.
2734 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2735 struct task_struct
*next
)
2737 struct mm_struct
*mm
, *oldmm
;
2739 prepare_task_switch(rq
, prev
, next
);
2740 trace_sched_switch(rq
, prev
, next
);
2742 oldmm
= prev
->active_mm
;
2744 * For paravirt, this is coupled with an exit in switch_to to
2745 * combine the page table reload and the switch backend into
2748 arch_enter_lazy_cpu_mode();
2750 if (unlikely(!mm
)) {
2751 next
->active_mm
= oldmm
;
2752 atomic_inc(&oldmm
->mm_count
);
2753 enter_lazy_tlb(oldmm
, next
);
2755 switch_mm(oldmm
, mm
, next
);
2757 if (unlikely(!prev
->mm
)) {
2758 prev
->active_mm
= NULL
;
2759 rq
->prev_mm
= oldmm
;
2762 * Since the runqueue lock will be released by the next
2763 * task (which is an invalid locking op but in the case
2764 * of the scheduler it's an obvious special-case), so we
2765 * do an early lockdep release here:
2767 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2768 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2771 /* Here we just switch the register state and the stack. */
2772 switch_to(prev
, next
, prev
);
2776 * this_rq must be evaluated again because prev may have moved
2777 * CPUs since it called schedule(), thus the 'rq' on its stack
2778 * frame will be invalid.
2780 finish_task_switch(this_rq(), prev
);
2784 * nr_running, nr_uninterruptible and nr_context_switches:
2786 * externally visible scheduler statistics: current number of runnable
2787 * threads, current number of uninterruptible-sleeping threads, total
2788 * number of context switches performed since bootup.
2790 unsigned long nr_running(void)
2792 unsigned long i
, sum
= 0;
2794 for_each_online_cpu(i
)
2795 sum
+= cpu_rq(i
)->nr_running
;
2800 unsigned long nr_uninterruptible(void)
2802 unsigned long i
, sum
= 0;
2804 for_each_possible_cpu(i
)
2805 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2808 * Since we read the counters lockless, it might be slightly
2809 * inaccurate. Do not allow it to go below zero though:
2811 if (unlikely((long)sum
< 0))
2817 unsigned long long nr_context_switches(void)
2820 unsigned long long sum
= 0;
2822 for_each_possible_cpu(i
)
2823 sum
+= cpu_rq(i
)->nr_switches
;
2828 unsigned long nr_iowait(void)
2830 unsigned long i
, sum
= 0;
2832 for_each_possible_cpu(i
)
2833 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2838 unsigned long nr_active(void)
2840 unsigned long i
, running
= 0, uninterruptible
= 0;
2842 for_each_online_cpu(i
) {
2843 running
+= cpu_rq(i
)->nr_running
;
2844 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2847 if (unlikely((long)uninterruptible
< 0))
2848 uninterruptible
= 0;
2850 return running
+ uninterruptible
;
2854 * Update rq->cpu_load[] statistics. This function is usually called every
2855 * scheduler tick (TICK_NSEC).
2857 static void update_cpu_load(struct rq
*this_rq
)
2859 unsigned long this_load
= this_rq
->load
.weight
;
2862 this_rq
->nr_load_updates
++;
2864 /* Update our load: */
2865 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2866 unsigned long old_load
, new_load
;
2868 /* scale is effectively 1 << i now, and >> i divides by scale */
2870 old_load
= this_rq
->cpu_load
[i
];
2871 new_load
= this_load
;
2873 * Round up the averaging division if load is increasing. This
2874 * prevents us from getting stuck on 9 if the load is 10, for
2877 if (new_load
> old_load
)
2878 new_load
+= scale
-1;
2879 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2886 * double_rq_lock - safely lock two runqueues
2888 * Note this does not disable interrupts like task_rq_lock,
2889 * you need to do so manually before calling.
2891 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2892 __acquires(rq1
->lock
)
2893 __acquires(rq2
->lock
)
2895 BUG_ON(!irqs_disabled());
2897 spin_lock(&rq1
->lock
);
2898 __acquire(rq2
->lock
); /* Fake it out ;) */
2901 spin_lock(&rq1
->lock
);
2902 spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
2904 spin_lock(&rq2
->lock
);
2905 spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
2908 update_rq_clock(rq1
);
2909 update_rq_clock(rq2
);
2913 * double_rq_unlock - safely unlock two runqueues
2915 * Note this does not restore interrupts like task_rq_unlock,
2916 * you need to do so manually after calling.
2918 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2919 __releases(rq1
->lock
)
2920 __releases(rq2
->lock
)
2922 spin_unlock(&rq1
->lock
);
2924 spin_unlock(&rq2
->lock
);
2926 __release(rq2
->lock
);
2930 * If dest_cpu is allowed for this process, migrate the task to it.
2931 * This is accomplished by forcing the cpu_allowed mask to only
2932 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2933 * the cpu_allowed mask is restored.
2935 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2937 struct migration_req req
;
2938 unsigned long flags
;
2941 rq
= task_rq_lock(p
, &flags
);
2942 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
2943 || unlikely(!cpu_active(dest_cpu
)))
2946 /* force the process onto the specified CPU */
2947 if (migrate_task(p
, dest_cpu
, &req
)) {
2948 /* Need to wait for migration thread (might exit: take ref). */
2949 struct task_struct
*mt
= rq
->migration_thread
;
2951 get_task_struct(mt
);
2952 task_rq_unlock(rq
, &flags
);
2953 wake_up_process(mt
);
2954 put_task_struct(mt
);
2955 wait_for_completion(&req
.done
);
2960 task_rq_unlock(rq
, &flags
);
2964 * sched_exec - execve() is a valuable balancing opportunity, because at
2965 * this point the task has the smallest effective memory and cache footprint.
2967 void sched_exec(void)
2969 int new_cpu
, this_cpu
= get_cpu();
2970 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2972 if (new_cpu
!= this_cpu
)
2973 sched_migrate_task(current
, new_cpu
);
2977 * pull_task - move a task from a remote runqueue to the local runqueue.
2978 * Both runqueues must be locked.
2980 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2981 struct rq
*this_rq
, int this_cpu
)
2983 deactivate_task(src_rq
, p
, 0);
2984 set_task_cpu(p
, this_cpu
);
2985 activate_task(this_rq
, p
, 0);
2987 * Note that idle threads have a prio of MAX_PRIO, for this test
2988 * to be always true for them.
2990 check_preempt_curr(this_rq
, p
, 0);
2994 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2997 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2998 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3002 * We do not migrate tasks that are:
3003 * 1) running (obviously), or
3004 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3005 * 3) are cache-hot on their current CPU.
3007 if (!cpumask_test_cpu(this_cpu
, &p
->cpus_allowed
)) {
3008 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3013 if (task_running(rq
, p
)) {
3014 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3019 * Aggressive migration if:
3020 * 1) task is cache cold, or
3021 * 2) too many balance attempts have failed.
3024 if (!task_hot(p
, rq
->clock
, sd
) ||
3025 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3026 #ifdef CONFIG_SCHEDSTATS
3027 if (task_hot(p
, rq
->clock
, sd
)) {
3028 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3029 schedstat_inc(p
, se
.nr_forced_migrations
);
3035 if (task_hot(p
, rq
->clock
, sd
)) {
3036 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3042 static unsigned long
3043 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3044 unsigned long max_load_move
, struct sched_domain
*sd
,
3045 enum cpu_idle_type idle
, int *all_pinned
,
3046 int *this_best_prio
, struct rq_iterator
*iterator
)
3048 int loops
= 0, pulled
= 0, pinned
= 0;
3049 struct task_struct
*p
;
3050 long rem_load_move
= max_load_move
;
3052 if (max_load_move
== 0)
3058 * Start the load-balancing iterator:
3060 p
= iterator
->start(iterator
->arg
);
3062 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3065 if ((p
->se
.load
.weight
>> 1) > rem_load_move
||
3066 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3067 p
= iterator
->next(iterator
->arg
);
3071 pull_task(busiest
, p
, this_rq
, this_cpu
);
3073 rem_load_move
-= p
->se
.load
.weight
;
3075 #ifdef CONFIG_PREEMPT
3077 * NEWIDLE balancing is a source of latency, so preemptible kernels
3078 * will stop after the first task is pulled to minimize the critical
3081 if (idle
== CPU_NEWLY_IDLE
)
3086 * We only want to steal up to the prescribed amount of weighted load.
3088 if (rem_load_move
> 0) {
3089 if (p
->prio
< *this_best_prio
)
3090 *this_best_prio
= p
->prio
;
3091 p
= iterator
->next(iterator
->arg
);
3096 * Right now, this is one of only two places pull_task() is called,
3097 * so we can safely collect pull_task() stats here rather than
3098 * inside pull_task().
3100 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3103 *all_pinned
= pinned
;
3105 return max_load_move
- rem_load_move
;
3109 * move_tasks tries to move up to max_load_move weighted load from busiest to
3110 * this_rq, as part of a balancing operation within domain "sd".
3111 * Returns 1 if successful and 0 otherwise.
3113 * Called with both runqueues locked.
3115 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3116 unsigned long max_load_move
,
3117 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3120 const struct sched_class
*class = sched_class_highest
;
3121 unsigned long total_load_moved
= 0;
3122 int this_best_prio
= this_rq
->curr
->prio
;
3126 class->load_balance(this_rq
, this_cpu
, busiest
,
3127 max_load_move
- total_load_moved
,
3128 sd
, idle
, all_pinned
, &this_best_prio
);
3129 class = class->next
;
3131 #ifdef CONFIG_PREEMPT
3133 * NEWIDLE balancing is a source of latency, so preemptible
3134 * kernels will stop after the first task is pulled to minimize
3135 * the critical section.
3137 if (idle
== CPU_NEWLY_IDLE
&& this_rq
->nr_running
)
3140 } while (class && max_load_move
> total_load_moved
);
3142 return total_load_moved
> 0;
3146 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3147 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3148 struct rq_iterator
*iterator
)
3150 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3154 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3155 pull_task(busiest
, p
, this_rq
, this_cpu
);
3157 * Right now, this is only the second place pull_task()
3158 * is called, so we can safely collect pull_task()
3159 * stats here rather than inside pull_task().
3161 schedstat_inc(sd
, lb_gained
[idle
]);
3165 p
= iterator
->next(iterator
->arg
);
3172 * move_one_task tries to move exactly one task from busiest to this_rq, as
3173 * part of active balancing operations within "domain".
3174 * Returns 1 if successful and 0 otherwise.
3176 * Called with both runqueues locked.
3178 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3179 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3181 const struct sched_class
*class;
3183 for (class = sched_class_highest
; class; class = class->next
)
3184 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3191 * find_busiest_group finds and returns the busiest CPU group within the
3192 * domain. It calculates and returns the amount of weighted load which
3193 * should be moved to restore balance via the imbalance parameter.
3195 static struct sched_group
*
3196 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3197 unsigned long *imbalance
, enum cpu_idle_type idle
,
3198 int *sd_idle
, const struct cpumask
*cpus
, int *balance
)
3200 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
3201 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
3202 unsigned long max_pull
;
3203 unsigned long busiest_load_per_task
, busiest_nr_running
;
3204 unsigned long this_load_per_task
, this_nr_running
;
3205 int load_idx
, group_imb
= 0;
3206 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3207 int power_savings_balance
= 1;
3208 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
3209 unsigned long min_nr_running
= ULONG_MAX
;
3210 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
3213 max_load
= this_load
= total_load
= total_pwr
= 0;
3214 busiest_load_per_task
= busiest_nr_running
= 0;
3215 this_load_per_task
= this_nr_running
= 0;
3217 if (idle
== CPU_NOT_IDLE
)
3218 load_idx
= sd
->busy_idx
;
3219 else if (idle
== CPU_NEWLY_IDLE
)
3220 load_idx
= sd
->newidle_idx
;
3222 load_idx
= sd
->idle_idx
;
3225 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
3228 int __group_imb
= 0;
3229 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3230 unsigned long sum_nr_running
, sum_weighted_load
;
3231 unsigned long sum_avg_load_per_task
;
3232 unsigned long avg_load_per_task
;
3234 local_group
= cpumask_test_cpu(this_cpu
,
3235 sched_group_cpus(group
));
3238 balance_cpu
= cpumask_first(sched_group_cpus(group
));
3240 /* Tally up the load of all CPUs in the group */
3241 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
3242 sum_avg_load_per_task
= avg_load_per_task
= 0;
3245 min_cpu_load
= ~0UL;
3247 for_each_cpu_and(i
, sched_group_cpus(group
), cpus
) {
3248 struct rq
*rq
= cpu_rq(i
);
3250 if (*sd_idle
&& rq
->nr_running
)
3253 /* Bias balancing toward cpus of our domain */
3255 if (idle_cpu(i
) && !first_idle_cpu
) {
3260 load
= target_load(i
, load_idx
);
3262 load
= source_load(i
, load_idx
);
3263 if (load
> max_cpu_load
)
3264 max_cpu_load
= load
;
3265 if (min_cpu_load
> load
)
3266 min_cpu_load
= load
;
3270 sum_nr_running
+= rq
->nr_running
;
3271 sum_weighted_load
+= weighted_cpuload(i
);
3273 sum_avg_load_per_task
+= cpu_avg_load_per_task(i
);
3277 * First idle cpu or the first cpu(busiest) in this sched group
3278 * is eligible for doing load balancing at this and above
3279 * domains. In the newly idle case, we will allow all the cpu's
3280 * to do the newly idle load balance.
3282 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3283 balance_cpu
!= this_cpu
&& balance
) {
3288 total_load
+= avg_load
;
3289 total_pwr
+= group
->__cpu_power
;
3291 /* Adjust by relative CPU power of the group */
3292 avg_load
= sg_div_cpu_power(group
,
3293 avg_load
* SCHED_LOAD_SCALE
);
3297 * Consider the group unbalanced when the imbalance is larger
3298 * than the average weight of two tasks.
3300 * APZ: with cgroup the avg task weight can vary wildly and
3301 * might not be a suitable number - should we keep a
3302 * normalized nr_running number somewhere that negates
3305 avg_load_per_task
= sg_div_cpu_power(group
,
3306 sum_avg_load_per_task
* SCHED_LOAD_SCALE
);
3308 if ((max_cpu_load
- min_cpu_load
) > 2*avg_load_per_task
)
3311 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3314 this_load
= avg_load
;
3316 this_nr_running
= sum_nr_running
;
3317 this_load_per_task
= sum_weighted_load
;
3318 } else if (avg_load
> max_load
&&
3319 (sum_nr_running
> group_capacity
|| __group_imb
)) {
3320 max_load
= avg_load
;
3322 busiest_nr_running
= sum_nr_running
;
3323 busiest_load_per_task
= sum_weighted_load
;
3324 group_imb
= __group_imb
;
3327 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3329 * Busy processors will not participate in power savings
3332 if (idle
== CPU_NOT_IDLE
||
3333 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3337 * If the local group is idle or completely loaded
3338 * no need to do power savings balance at this domain
3340 if (local_group
&& (this_nr_running
>= group_capacity
||
3342 power_savings_balance
= 0;
3345 * If a group is already running at full capacity or idle,
3346 * don't include that group in power savings calculations
3348 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
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 ((sum_nr_running
< min_nr_running
) ||
3358 (sum_nr_running
== min_nr_running
&&
3359 cpumask_first(sched_group_cpus(group
)) >
3360 cpumask_first(sched_group_cpus(group_min
)))) {
3362 min_nr_running
= sum_nr_running
;
3363 min_load_per_task
= sum_weighted_load
/
3368 * Calculate the group which is almost near its
3369 * capacity but still has some space to pick up some load
3370 * from other group and save more power
3372 if (sum_nr_running
<= group_capacity
- 1) {
3373 if (sum_nr_running
> leader_nr_running
||
3374 (sum_nr_running
== leader_nr_running
&&
3375 cpumask_first(sched_group_cpus(group
)) <
3376 cpumask_first(sched_group_cpus(group_leader
)))) {
3377 group_leader
= group
;
3378 leader_nr_running
= sum_nr_running
;
3383 group
= group
->next
;
3384 } while (group
!= sd
->groups
);
3386 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3389 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3391 if (this_load
>= avg_load
||
3392 100*max_load
<= sd
->imbalance_pct
*this_load
)
3395 busiest_load_per_task
/= busiest_nr_running
;
3397 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3400 * We're trying to get all the cpus to the average_load, so we don't
3401 * want to push ourselves above the average load, nor do we wish to
3402 * reduce the max loaded cpu below the average load, as either of these
3403 * actions would just result in more rebalancing later, and ping-pong
3404 * tasks around. Thus we look for the minimum possible imbalance.
3405 * Negative imbalances (*we* are more loaded than anyone else) will
3406 * be counted as no imbalance for these purposes -- we can't fix that
3407 * by pulling tasks to us. Be careful of negative numbers as they'll
3408 * appear as very large values with unsigned longs.
3410 if (max_load
<= busiest_load_per_task
)
3414 * In the presence of smp nice balancing, certain scenarios can have
3415 * max load less than avg load(as we skip the groups at or below
3416 * its cpu_power, while calculating max_load..)
3418 if (max_load
< avg_load
) {
3420 goto small_imbalance
;
3423 /* Don't want to pull so many tasks that a group would go idle */
3424 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3426 /* How much load to actually move to equalise the imbalance */
3427 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3428 (avg_load
- this_load
) * this->__cpu_power
)
3432 * if *imbalance is less than the average load per runnable task
3433 * there is no gaurantee that any tasks will be moved so we'll have
3434 * a think about bumping its value to force at least one task to be
3437 if (*imbalance
< busiest_load_per_task
) {
3438 unsigned long tmp
, pwr_now
, pwr_move
;
3442 pwr_move
= pwr_now
= 0;
3444 if (this_nr_running
) {
3445 this_load_per_task
/= this_nr_running
;
3446 if (busiest_load_per_task
> this_load_per_task
)
3449 this_load_per_task
= cpu_avg_load_per_task(this_cpu
);
3451 if (max_load
- this_load
+ busiest_load_per_task
>=
3452 busiest_load_per_task
* imbn
) {
3453 *imbalance
= busiest_load_per_task
;
3458 * OK, we don't have enough imbalance to justify moving tasks,
3459 * however we may be able to increase total CPU power used by
3463 pwr_now
+= busiest
->__cpu_power
*
3464 min(busiest_load_per_task
, max_load
);
3465 pwr_now
+= this->__cpu_power
*
3466 min(this_load_per_task
, this_load
);
3467 pwr_now
/= SCHED_LOAD_SCALE
;
3469 /* Amount of load we'd subtract */
3470 tmp
= sg_div_cpu_power(busiest
,
3471 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3473 pwr_move
+= busiest
->__cpu_power
*
3474 min(busiest_load_per_task
, max_load
- tmp
);
3476 /* Amount of load we'd add */
3477 if (max_load
* busiest
->__cpu_power
<
3478 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3479 tmp
= sg_div_cpu_power(this,
3480 max_load
* busiest
->__cpu_power
);
3482 tmp
= sg_div_cpu_power(this,
3483 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3484 pwr_move
+= this->__cpu_power
*
3485 min(this_load_per_task
, this_load
+ tmp
);
3486 pwr_move
/= SCHED_LOAD_SCALE
;
3488 /* Move if we gain throughput */
3489 if (pwr_move
> pwr_now
)
3490 *imbalance
= busiest_load_per_task
;
3496 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3497 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3500 if (this == group_leader
&& group_leader
!= group_min
) {
3501 *imbalance
= min_load_per_task
;
3502 if (sched_mc_power_savings
>= POWERSAVINGS_BALANCE_WAKEUP
) {
3503 cpu_rq(this_cpu
)->rd
->sched_mc_preferred_wakeup_cpu
=
3504 cpumask_first(sched_group_cpus(group_leader
));
3515 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3518 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3519 unsigned long imbalance
, const struct cpumask
*cpus
)
3521 struct rq
*busiest
= NULL
, *rq
;
3522 unsigned long max_load
= 0;
3525 for_each_cpu(i
, sched_group_cpus(group
)) {
3528 if (!cpumask_test_cpu(i
, cpus
))
3532 wl
= weighted_cpuload(i
);
3534 if (rq
->nr_running
== 1 && wl
> imbalance
)
3537 if (wl
> max_load
) {
3547 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3548 * so long as it is large enough.
3550 #define MAX_PINNED_INTERVAL 512
3553 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3554 * tasks if there is an imbalance.
3556 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3557 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3558 int *balance
, struct cpumask
*cpus
)
3560 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3561 struct sched_group
*group
;
3562 unsigned long imbalance
;
3564 unsigned long flags
;
3566 cpumask_setall(cpus
);
3569 * When power savings policy is enabled for the parent domain, idle
3570 * sibling can pick up load irrespective of busy siblings. In this case,
3571 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3572 * portraying it as CPU_NOT_IDLE.
3574 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3575 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3578 schedstat_inc(sd
, lb_count
[idle
]);
3582 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3589 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3593 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3595 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3599 BUG_ON(busiest
== this_rq
);
3601 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3604 if (busiest
->nr_running
> 1) {
3606 * Attempt to move tasks. If find_busiest_group has found
3607 * an imbalance but busiest->nr_running <= 1, the group is
3608 * still unbalanced. ld_moved simply stays zero, so it is
3609 * correctly treated as an imbalance.
3611 local_irq_save(flags
);
3612 double_rq_lock(this_rq
, busiest
);
3613 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3614 imbalance
, sd
, idle
, &all_pinned
);
3615 double_rq_unlock(this_rq
, busiest
);
3616 local_irq_restore(flags
);
3619 * some other cpu did the load balance for us.
3621 if (ld_moved
&& this_cpu
!= smp_processor_id())
3622 resched_cpu(this_cpu
);
3624 /* All tasks on this runqueue were pinned by CPU affinity */
3625 if (unlikely(all_pinned
)) {
3626 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
3627 if (!cpumask_empty(cpus
))
3634 schedstat_inc(sd
, lb_failed
[idle
]);
3635 sd
->nr_balance_failed
++;
3637 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3639 spin_lock_irqsave(&busiest
->lock
, flags
);
3641 /* don't kick the migration_thread, if the curr
3642 * task on busiest cpu can't be moved to this_cpu
3644 if (!cpumask_test_cpu(this_cpu
,
3645 &busiest
->curr
->cpus_allowed
)) {
3646 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3648 goto out_one_pinned
;
3651 if (!busiest
->active_balance
) {
3652 busiest
->active_balance
= 1;
3653 busiest
->push_cpu
= this_cpu
;
3656 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3658 wake_up_process(busiest
->migration_thread
);
3661 * We've kicked active balancing, reset the failure
3664 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3667 sd
->nr_balance_failed
= 0;
3669 if (likely(!active_balance
)) {
3670 /* We were unbalanced, so reset the balancing interval */
3671 sd
->balance_interval
= sd
->min_interval
;
3674 * If we've begun active balancing, start to back off. This
3675 * case may not be covered by the all_pinned logic if there
3676 * is only 1 task on the busy runqueue (because we don't call
3679 if (sd
->balance_interval
< sd
->max_interval
)
3680 sd
->balance_interval
*= 2;
3683 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3684 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3690 schedstat_inc(sd
, lb_balanced
[idle
]);
3692 sd
->nr_balance_failed
= 0;
3695 /* tune up the balancing interval */
3696 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3697 (sd
->balance_interval
< sd
->max_interval
))
3698 sd
->balance_interval
*= 2;
3700 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3701 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3712 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3713 * tasks if there is an imbalance.
3715 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3716 * this_rq is locked.
3719 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3720 struct cpumask
*cpus
)
3722 struct sched_group
*group
;
3723 struct rq
*busiest
= NULL
;
3724 unsigned long imbalance
;
3729 cpumask_setall(cpus
);
3732 * When power savings policy is enabled for the parent domain, idle
3733 * sibling can pick up load irrespective of busy siblings. In this case,
3734 * let the state of idle sibling percolate up as IDLE, instead of
3735 * portraying it as CPU_NOT_IDLE.
3737 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3738 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3741 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3743 update_shares_locked(this_rq
, sd
);
3744 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3745 &sd_idle
, cpus
, NULL
);
3747 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3751 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3753 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3757 BUG_ON(busiest
== this_rq
);
3759 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3762 if (busiest
->nr_running
> 1) {
3763 /* Attempt to move tasks */
3764 double_lock_balance(this_rq
, busiest
);
3765 /* this_rq->clock is already updated */
3766 update_rq_clock(busiest
);
3767 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3768 imbalance
, sd
, CPU_NEWLY_IDLE
,
3770 double_unlock_balance(this_rq
, busiest
);
3772 if (unlikely(all_pinned
)) {
3773 cpumask_clear_cpu(cpu_of(busiest
), cpus
);
3774 if (!cpumask_empty(cpus
))
3780 int active_balance
= 0;
3782 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3783 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3784 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3787 if (sched_mc_power_savings
< POWERSAVINGS_BALANCE_WAKEUP
)
3790 if (sd
->nr_balance_failed
++ < 2)
3794 * The only task running in a non-idle cpu can be moved to this
3795 * cpu in an attempt to completely freeup the other CPU
3796 * package. The same method used to move task in load_balance()
3797 * have been extended for load_balance_newidle() to speedup
3798 * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
3800 * The package power saving logic comes from
3801 * find_busiest_group(). If there are no imbalance, then
3802 * f_b_g() will return NULL. However when sched_mc={1,2} then
3803 * f_b_g() will select a group from which a running task may be
3804 * pulled to this cpu in order to make the other package idle.
3805 * If there is no opportunity to make a package idle and if
3806 * there are no imbalance, then f_b_g() will return NULL and no
3807 * action will be taken in load_balance_newidle().
3809 * Under normal task pull operation due to imbalance, there
3810 * will be more than one task in the source run queue and
3811 * move_tasks() will succeed. ld_moved will be true and this
3812 * active balance code will not be triggered.
3815 /* Lock busiest in correct order while this_rq is held */
3816 double_lock_balance(this_rq
, busiest
);
3819 * don't kick the migration_thread, if the curr
3820 * task on busiest cpu can't be moved to this_cpu
3822 if (!cpumask_test_cpu(this_cpu
, &busiest
->curr
->cpus_allowed
)) {
3823 double_unlock_balance(this_rq
, busiest
);
3828 if (!busiest
->active_balance
) {
3829 busiest
->active_balance
= 1;
3830 busiest
->push_cpu
= this_cpu
;
3834 double_unlock_balance(this_rq
, busiest
);
3836 * Should not call ttwu while holding a rq->lock
3838 spin_unlock(&this_rq
->lock
);
3840 wake_up_process(busiest
->migration_thread
);
3841 spin_lock(&this_rq
->lock
);
3844 sd
->nr_balance_failed
= 0;
3846 update_shares_locked(this_rq
, sd
);
3850 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3851 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3852 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3854 sd
->nr_balance_failed
= 0;
3860 * idle_balance is called by schedule() if this_cpu is about to become
3861 * idle. Attempts to pull tasks from other CPUs.
3863 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3865 struct sched_domain
*sd
;
3866 int pulled_task
= 0;
3867 unsigned long next_balance
= jiffies
+ HZ
;
3868 cpumask_var_t tmpmask
;
3870 if (!alloc_cpumask_var(&tmpmask
, GFP_ATOMIC
))
3873 for_each_domain(this_cpu
, sd
) {
3874 unsigned long interval
;
3876 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3879 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3880 /* If we've pulled tasks over stop searching: */
3881 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3884 interval
= msecs_to_jiffies(sd
->balance_interval
);
3885 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3886 next_balance
= sd
->last_balance
+ interval
;
3890 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3892 * We are going idle. next_balance may be set based on
3893 * a busy processor. So reset next_balance.
3895 this_rq
->next_balance
= next_balance
;
3897 free_cpumask_var(tmpmask
);
3901 * active_load_balance is run by migration threads. It pushes running tasks
3902 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3903 * running on each physical CPU where possible, and avoids physical /
3904 * logical imbalances.
3906 * Called with busiest_rq locked.
3908 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3910 int target_cpu
= busiest_rq
->push_cpu
;
3911 struct sched_domain
*sd
;
3912 struct rq
*target_rq
;
3914 /* Is there any task to move? */
3915 if (busiest_rq
->nr_running
<= 1)
3918 target_rq
= cpu_rq(target_cpu
);
3921 * This condition is "impossible", if it occurs
3922 * we need to fix it. Originally reported by
3923 * Bjorn Helgaas on a 128-cpu setup.
3925 BUG_ON(busiest_rq
== target_rq
);
3927 /* move a task from busiest_rq to target_rq */
3928 double_lock_balance(busiest_rq
, target_rq
);
3929 update_rq_clock(busiest_rq
);
3930 update_rq_clock(target_rq
);
3932 /* Search for an sd spanning us and the target CPU. */
3933 for_each_domain(target_cpu
, sd
) {
3934 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3935 cpumask_test_cpu(busiest_cpu
, sched_domain_span(sd
)))
3940 schedstat_inc(sd
, alb_count
);
3942 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3944 schedstat_inc(sd
, alb_pushed
);
3946 schedstat_inc(sd
, alb_failed
);
3948 double_unlock_balance(busiest_rq
, target_rq
);
3953 atomic_t load_balancer
;
3954 cpumask_var_t cpu_mask
;
3955 } nohz ____cacheline_aligned
= {
3956 .load_balancer
= ATOMIC_INIT(-1),
3960 * This routine will try to nominate the ilb (idle load balancing)
3961 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3962 * load balancing on behalf of all those cpus. If all the cpus in the system
3963 * go into this tickless mode, then there will be no ilb owner (as there is
3964 * no need for one) and all the cpus will sleep till the next wakeup event
3967 * For the ilb owner, tick is not stopped. And this tick will be used
3968 * for idle load balancing. ilb owner will still be part of
3971 * While stopping the tick, this cpu will become the ilb owner if there
3972 * is no other owner. And will be the owner till that cpu becomes busy
3973 * or if all cpus in the system stop their ticks at which point
3974 * there is no need for ilb owner.
3976 * When the ilb owner becomes busy, it nominates another owner, during the
3977 * next busy scheduler_tick()
3979 int select_nohz_load_balancer(int stop_tick
)
3981 int cpu
= smp_processor_id();
3984 cpu_rq(cpu
)->in_nohz_recently
= 1;
3986 if (!cpu_active(cpu
)) {
3987 if (atomic_read(&nohz
.load_balancer
) != cpu
)
3991 * If we are going offline and still the leader,
3994 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4000 cpumask_set_cpu(cpu
, nohz
.cpu_mask
);
4002 /* time for ilb owner also to sleep */
4003 if (cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4004 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4005 atomic_set(&nohz
.load_balancer
, -1);
4009 if (atomic_read(&nohz
.load_balancer
) == -1) {
4010 /* make me the ilb owner */
4011 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4013 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
4016 if (!cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4019 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4021 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4022 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4029 static DEFINE_SPINLOCK(balancing
);
4032 * It checks each scheduling domain to see if it is due to be balanced,
4033 * and initiates a balancing operation if so.
4035 * Balancing parameters are set up in arch_init_sched_domains.
4037 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4040 struct rq
*rq
= cpu_rq(cpu
);
4041 unsigned long interval
;
4042 struct sched_domain
*sd
;
4043 /* Earliest time when we have to do rebalance again */
4044 unsigned long next_balance
= jiffies
+ 60*HZ
;
4045 int update_next_balance
= 0;
4049 /* Fails alloc? Rebalancing probably not a priority right now. */
4050 if (!alloc_cpumask_var(&tmp
, GFP_ATOMIC
))
4053 for_each_domain(cpu
, sd
) {
4054 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4057 interval
= sd
->balance_interval
;
4058 if (idle
!= CPU_IDLE
)
4059 interval
*= sd
->busy_factor
;
4061 /* scale ms to jiffies */
4062 interval
= msecs_to_jiffies(interval
);
4063 if (unlikely(!interval
))
4065 if (interval
> HZ
*NR_CPUS
/10)
4066 interval
= HZ
*NR_CPUS
/10;
4068 need_serialize
= sd
->flags
& SD_SERIALIZE
;
4070 if (need_serialize
) {
4071 if (!spin_trylock(&balancing
))
4075 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4076 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, tmp
)) {
4078 * We've pulled tasks over so either we're no
4079 * longer idle, or one of our SMT siblings is
4082 idle
= CPU_NOT_IDLE
;
4084 sd
->last_balance
= jiffies
;
4087 spin_unlock(&balancing
);
4089 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4090 next_balance
= sd
->last_balance
+ interval
;
4091 update_next_balance
= 1;
4095 * Stop the load balance at this level. There is another
4096 * CPU in our sched group which is doing load balancing more
4104 * next_balance will be updated only when there is a need.
4105 * When the cpu is attached to null domain for ex, it will not be
4108 if (likely(update_next_balance
))
4109 rq
->next_balance
= next_balance
;
4111 free_cpumask_var(tmp
);
4115 * run_rebalance_domains is triggered when needed from the scheduler tick.
4116 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4117 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4119 static void run_rebalance_domains(struct softirq_action
*h
)
4121 int this_cpu
= smp_processor_id();
4122 struct rq
*this_rq
= cpu_rq(this_cpu
);
4123 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4124 CPU_IDLE
: CPU_NOT_IDLE
;
4126 rebalance_domains(this_cpu
, idle
);
4130 * If this cpu is the owner for idle load balancing, then do the
4131 * balancing on behalf of the other idle cpus whose ticks are
4134 if (this_rq
->idle_at_tick
&&
4135 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4139 for_each_cpu(balance_cpu
, nohz
.cpu_mask
) {
4140 if (balance_cpu
== this_cpu
)
4144 * If this cpu gets work to do, stop the load balancing
4145 * work being done for other cpus. Next load
4146 * balancing owner will pick it up.
4151 rebalance_domains(balance_cpu
, CPU_IDLE
);
4153 rq
= cpu_rq(balance_cpu
);
4154 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4155 this_rq
->next_balance
= rq
->next_balance
;
4162 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4164 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4165 * idle load balancing owner or decide to stop the periodic load balancing,
4166 * if the whole system is idle.
4168 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4172 * If we were in the nohz mode recently and busy at the current
4173 * scheduler tick, then check if we need to nominate new idle
4176 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4177 rq
->in_nohz_recently
= 0;
4179 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4180 cpumask_clear_cpu(cpu
, nohz
.cpu_mask
);
4181 atomic_set(&nohz
.load_balancer
, -1);
4184 if (atomic_read(&nohz
.load_balancer
) == -1) {
4186 * simple selection for now: Nominate the
4187 * first cpu in the nohz list to be the next
4190 * TBD: Traverse the sched domains and nominate
4191 * the nearest cpu in the nohz.cpu_mask.
4193 int ilb
= cpumask_first(nohz
.cpu_mask
);
4195 if (ilb
< nr_cpu_ids
)
4201 * If this cpu is idle and doing idle load balancing for all the
4202 * cpus with ticks stopped, is it time for that to stop?
4204 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4205 cpumask_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4211 * If this cpu is idle and the idle load balancing is done by
4212 * someone else, then no need raise the SCHED_SOFTIRQ
4214 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4215 cpumask_test_cpu(cpu
, nohz
.cpu_mask
))
4218 if (time_after_eq(jiffies
, rq
->next_balance
))
4219 raise_softirq(SCHED_SOFTIRQ
);
4222 #else /* CONFIG_SMP */
4225 * on UP we do not need to balance between CPUs:
4227 static inline void idle_balance(int cpu
, struct rq
*rq
)
4233 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4235 EXPORT_PER_CPU_SYMBOL(kstat
);
4238 * Return any ns on the sched_clock that have not yet been banked in
4239 * @p in case that task is currently running.
4241 unsigned long long task_delta_exec(struct task_struct
*p
)
4243 unsigned long flags
;
4247 rq
= task_rq_lock(p
, &flags
);
4249 if (task_current(rq
, p
)) {
4252 update_rq_clock(rq
);
4253 delta_exec
= rq
->clock
- p
->se
.exec_start
;
4254 if ((s64
)delta_exec
> 0)
4258 task_rq_unlock(rq
, &flags
);
4264 * Account user cpu time to a process.
4265 * @p: the process that the cpu time gets accounted to
4266 * @cputime: the cpu time spent in user space since the last update
4267 * @cputime_scaled: cputime scaled by cpu frequency
4269 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
4270 cputime_t cputime_scaled
)
4272 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4275 /* Add user time to process. */
4276 p
->utime
= cputime_add(p
->utime
, cputime
);
4277 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4278 account_group_user_time(p
, cputime
);
4280 /* Add user time to cpustat. */
4281 tmp
= cputime_to_cputime64(cputime
);
4282 if (TASK_NICE(p
) > 0)
4283 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
4285 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4286 /* Account for user time used */
4287 acct_update_integrals(p
);
4291 * Account guest cpu time to a process.
4292 * @p: the process that the cpu time gets accounted to
4293 * @cputime: the cpu time spent in virtual machine since the last update
4294 * @cputime_scaled: cputime scaled by cpu frequency
4296 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
4297 cputime_t cputime_scaled
)
4300 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4302 tmp
= cputime_to_cputime64(cputime
);
4304 /* Add guest time to process. */
4305 p
->utime
= cputime_add(p
->utime
, cputime
);
4306 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
4307 account_group_user_time(p
, cputime
);
4308 p
->gtime
= cputime_add(p
->gtime
, cputime
);
4310 /* Add guest time to cpustat. */
4311 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4312 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
4316 * Account system cpu time to a process.
4317 * @p: the process that the cpu time gets accounted to
4318 * @hardirq_offset: the offset to subtract from hardirq_count()
4319 * @cputime: the cpu time spent in kernel space since the last update
4320 * @cputime_scaled: cputime scaled by cpu frequency
4322 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
4323 cputime_t cputime
, cputime_t cputime_scaled
)
4325 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4328 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
4329 account_guest_time(p
, cputime
, cputime_scaled
);
4333 /* Add system time to process. */
4334 p
->stime
= cputime_add(p
->stime
, cputime
);
4335 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
4336 account_group_system_time(p
, cputime
);
4338 /* Add system time to cpustat. */
4339 tmp
= cputime_to_cputime64(cputime
);
4340 if (hardirq_count() - hardirq_offset
)
4341 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
4342 else if (softirq_count())
4343 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
4345 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
4347 /* Account for system time used */
4348 acct_update_integrals(p
);
4352 * Account for involuntary wait time.
4353 * @steal: the cpu time spent in involuntary wait
4355 void account_steal_time(cputime_t cputime
)
4357 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4358 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
4360 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
4364 * Account for idle time.
4365 * @cputime: the cpu time spent in idle wait
4367 void account_idle_time(cputime_t cputime
)
4369 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4370 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
4371 struct rq
*rq
= this_rq();
4373 if (atomic_read(&rq
->nr_iowait
) > 0)
4374 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
4376 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
4379 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
4382 * Account a single tick of cpu time.
4383 * @p: the process that the cpu time gets accounted to
4384 * @user_tick: indicates if the tick is a user or a system tick
4386 void account_process_tick(struct task_struct
*p
, int user_tick
)
4388 cputime_t one_jiffy
= jiffies_to_cputime(1);
4389 cputime_t one_jiffy_scaled
= cputime_to_scaled(one_jiffy
);
4390 struct rq
*rq
= this_rq();
4393 account_user_time(p
, one_jiffy
, one_jiffy_scaled
);
4394 else if (p
!= rq
->idle
)
4395 account_system_time(p
, HARDIRQ_OFFSET
, one_jiffy
,
4398 account_idle_time(one_jiffy
);
4402 * Account multiple ticks of steal time.
4403 * @p: the process from which the cpu time has been stolen
4404 * @ticks: number of stolen ticks
4406 void account_steal_ticks(unsigned long ticks
)
4408 account_steal_time(jiffies_to_cputime(ticks
));
4412 * Account multiple ticks of idle time.
4413 * @ticks: number of stolen ticks
4415 void account_idle_ticks(unsigned long ticks
)
4417 account_idle_time(jiffies_to_cputime(ticks
));
4423 * Use precise platform statistics if available:
4425 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
4426 cputime_t
task_utime(struct task_struct
*p
)
4431 cputime_t
task_stime(struct task_struct
*p
)
4436 cputime_t
task_utime(struct task_struct
*p
)
4438 clock_t utime
= cputime_to_clock_t(p
->utime
),
4439 total
= utime
+ cputime_to_clock_t(p
->stime
);
4443 * Use CFS's precise accounting:
4445 temp
= (u64
)nsec_to_clock_t(p
->se
.sum_exec_runtime
);
4449 do_div(temp
, total
);
4451 utime
= (clock_t)temp
;
4453 p
->prev_utime
= max(p
->prev_utime
, clock_t_to_cputime(utime
));
4454 return p
->prev_utime
;
4457 cputime_t
task_stime(struct task_struct
*p
)
4462 * Use CFS's precise accounting. (we subtract utime from
4463 * the total, to make sure the total observed by userspace
4464 * grows monotonically - apps rely on that):
4466 stime
= nsec_to_clock_t(p
->se
.sum_exec_runtime
) -
4467 cputime_to_clock_t(task_utime(p
));
4470 p
->prev_stime
= max(p
->prev_stime
, clock_t_to_cputime(stime
));
4472 return p
->prev_stime
;
4476 inline cputime_t
task_gtime(struct task_struct
*p
)
4482 * This function gets called by the timer code, with HZ frequency.
4483 * We call it with interrupts disabled.
4485 * It also gets called by the fork code, when changing the parent's
4488 void scheduler_tick(void)
4490 int cpu
= smp_processor_id();
4491 struct rq
*rq
= cpu_rq(cpu
);
4492 struct task_struct
*curr
= rq
->curr
;
4496 spin_lock(&rq
->lock
);
4497 update_rq_clock(rq
);
4498 update_cpu_load(rq
);
4499 curr
->sched_class
->task_tick(rq
, curr
, 0);
4500 spin_unlock(&rq
->lock
);
4503 rq
->idle_at_tick
= idle_cpu(cpu
);
4504 trigger_load_balance(rq
, cpu
);
4508 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
4509 defined(CONFIG_PREEMPT_TRACER))
4511 static inline unsigned long get_parent_ip(unsigned long addr
)
4513 if (in_lock_functions(addr
)) {
4514 addr
= CALLER_ADDR2
;
4515 if (in_lock_functions(addr
))
4516 addr
= CALLER_ADDR3
;
4521 void __kprobes
add_preempt_count(int val
)
4523 #ifdef CONFIG_DEBUG_PREEMPT
4527 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4530 preempt_count() += val
;
4531 #ifdef CONFIG_DEBUG_PREEMPT
4533 * Spinlock count overflowing soon?
4535 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4538 if (preempt_count() == val
)
4539 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4541 EXPORT_SYMBOL(add_preempt_count
);
4543 void __kprobes
sub_preempt_count(int val
)
4545 #ifdef CONFIG_DEBUG_PREEMPT
4549 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
4552 * Is the spinlock portion underflowing?
4554 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4555 !(preempt_count() & PREEMPT_MASK
)))
4559 if (preempt_count() == val
)
4560 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
4561 preempt_count() -= val
;
4563 EXPORT_SYMBOL(sub_preempt_count
);
4568 * Print scheduling while atomic bug:
4570 static noinline
void __schedule_bug(struct task_struct
*prev
)
4572 struct pt_regs
*regs
= get_irq_regs();
4574 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4575 prev
->comm
, prev
->pid
, preempt_count());
4577 debug_show_held_locks(prev
);
4579 if (irqs_disabled())
4580 print_irqtrace_events(prev
);
4589 * Various schedule()-time debugging checks and statistics:
4591 static inline void schedule_debug(struct task_struct
*prev
)
4594 * Test if we are atomic. Since do_exit() needs to call into
4595 * schedule() atomically, we ignore that path for now.
4596 * Otherwise, whine if we are scheduling when we should not be.
4598 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4599 __schedule_bug(prev
);
4601 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4603 schedstat_inc(this_rq(), sched_count
);
4604 #ifdef CONFIG_SCHEDSTATS
4605 if (unlikely(prev
->lock_depth
>= 0)) {
4606 schedstat_inc(this_rq(), bkl_count
);
4607 schedstat_inc(prev
, sched_info
.bkl_count
);
4613 * Pick up the highest-prio task:
4615 static inline struct task_struct
*
4616 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4618 const struct sched_class
*class;
4619 struct task_struct
*p
;
4622 * Optimization: we know that if all tasks are in
4623 * the fair class we can call that function directly:
4625 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4626 p
= fair_sched_class
.pick_next_task(rq
);
4631 class = sched_class_highest
;
4633 p
= class->pick_next_task(rq
);
4637 * Will never be NULL as the idle class always
4638 * returns a non-NULL p:
4640 class = class->next
;
4645 * schedule() is the main scheduler function.
4647 asmlinkage
void __sched
schedule(void)
4649 struct task_struct
*prev
, *next
;
4650 unsigned long *switch_count
;
4656 cpu
= smp_processor_id();
4660 switch_count
= &prev
->nivcsw
;
4662 release_kernel_lock(prev
);
4663 need_resched_nonpreemptible
:
4665 schedule_debug(prev
);
4667 if (sched_feat(HRTICK
))
4670 spin_lock_irq(&rq
->lock
);
4671 update_rq_clock(rq
);
4672 clear_tsk_need_resched(prev
);
4674 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4675 if (unlikely(signal_pending_state(prev
->state
, prev
)))
4676 prev
->state
= TASK_RUNNING
;
4678 deactivate_task(rq
, prev
, 1);
4679 switch_count
= &prev
->nvcsw
;
4683 if (prev
->sched_class
->pre_schedule
)
4684 prev
->sched_class
->pre_schedule(rq
, prev
);
4687 if (unlikely(!rq
->nr_running
))
4688 idle_balance(cpu
, rq
);
4690 prev
->sched_class
->put_prev_task(rq
, prev
);
4691 next
= pick_next_task(rq
, prev
);
4693 if (likely(prev
!= next
)) {
4694 sched_info_switch(prev
, next
);
4700 context_switch(rq
, prev
, next
); /* unlocks the rq */
4702 * the context switch might have flipped the stack from under
4703 * us, hence refresh the local variables.
4705 cpu
= smp_processor_id();
4708 spin_unlock_irq(&rq
->lock
);
4710 if (unlikely(reacquire_kernel_lock(current
) < 0))
4711 goto need_resched_nonpreemptible
;
4713 preempt_enable_no_resched();
4714 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4717 EXPORT_SYMBOL(schedule
);
4719 #ifdef CONFIG_PREEMPT
4721 * this is the entry point to schedule() from in-kernel preemption
4722 * off of preempt_enable. Kernel preemptions off return from interrupt
4723 * occur there and call schedule directly.
4725 asmlinkage
void __sched
preempt_schedule(void)
4727 struct thread_info
*ti
= current_thread_info();
4730 * If there is a non-zero preempt_count or interrupts are disabled,
4731 * we do not want to preempt the current task. Just return..
4733 if (likely(ti
->preempt_count
|| irqs_disabled()))
4737 add_preempt_count(PREEMPT_ACTIVE
);
4739 sub_preempt_count(PREEMPT_ACTIVE
);
4742 * Check again in case we missed a preemption opportunity
4743 * between schedule and now.
4746 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4748 EXPORT_SYMBOL(preempt_schedule
);
4751 * this is the entry point to schedule() from kernel preemption
4752 * off of irq context.
4753 * Note, that this is called and return with irqs disabled. This will
4754 * protect us against recursive calling from irq.
4756 asmlinkage
void __sched
preempt_schedule_irq(void)
4758 struct thread_info
*ti
= current_thread_info();
4760 /* Catch callers which need to be fixed */
4761 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4764 add_preempt_count(PREEMPT_ACTIVE
);
4767 local_irq_disable();
4768 sub_preempt_count(PREEMPT_ACTIVE
);
4771 * Check again in case we missed a preemption opportunity
4772 * between schedule and now.
4775 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4778 #endif /* CONFIG_PREEMPT */
4780 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4783 return try_to_wake_up(curr
->private, mode
, sync
);
4785 EXPORT_SYMBOL(default_wake_function
);
4788 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4789 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4790 * number) then we wake all the non-exclusive tasks and one exclusive task.
4792 * There are circumstances in which we can try to wake a task which has already
4793 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4794 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4796 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4797 int nr_exclusive
, int sync
, void *key
)
4799 wait_queue_t
*curr
, *next
;
4801 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4802 unsigned flags
= curr
->flags
;
4804 if (curr
->func(curr
, mode
, sync
, key
) &&
4805 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4811 * __wake_up - wake up threads blocked on a waitqueue.
4813 * @mode: which threads
4814 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4815 * @key: is directly passed to the wakeup function
4817 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4818 int nr_exclusive
, void *key
)
4820 unsigned long flags
;
4822 spin_lock_irqsave(&q
->lock
, flags
);
4823 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4824 spin_unlock_irqrestore(&q
->lock
, flags
);
4826 EXPORT_SYMBOL(__wake_up
);
4829 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4831 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4833 __wake_up_common(q
, mode
, 1, 0, NULL
);
4837 * __wake_up_sync - wake up threads blocked on a waitqueue.
4839 * @mode: which threads
4840 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4842 * The sync wakeup differs that the waker knows that it will schedule
4843 * away soon, so while the target thread will be woken up, it will not
4844 * be migrated to another CPU - ie. the two threads are 'synchronized'
4845 * with each other. This can prevent needless bouncing between CPUs.
4847 * On UP it can prevent extra preemption.
4850 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4852 unsigned long flags
;
4858 if (unlikely(!nr_exclusive
))
4861 spin_lock_irqsave(&q
->lock
, flags
);
4862 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4863 spin_unlock_irqrestore(&q
->lock
, flags
);
4865 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4868 * complete: - signals a single thread waiting on this completion
4869 * @x: holds the state of this particular completion
4871 * This will wake up a single thread waiting on this completion. Threads will be
4872 * awakened in the same order in which they were queued.
4874 * See also complete_all(), wait_for_completion() and related routines.
4876 void complete(struct completion
*x
)
4878 unsigned long flags
;
4880 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4882 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4883 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4885 EXPORT_SYMBOL(complete
);
4888 * complete_all: - signals all threads waiting on this completion
4889 * @x: holds the state of this particular completion
4891 * This will wake up all threads waiting on this particular completion event.
4893 void complete_all(struct completion
*x
)
4895 unsigned long flags
;
4897 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4898 x
->done
+= UINT_MAX
/2;
4899 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4900 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4902 EXPORT_SYMBOL(complete_all
);
4904 static inline long __sched
4905 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4908 DECLARE_WAITQUEUE(wait
, current
);
4910 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4911 __add_wait_queue_tail(&x
->wait
, &wait
);
4913 if (signal_pending_state(state
, current
)) {
4914 timeout
= -ERESTARTSYS
;
4917 __set_current_state(state
);
4918 spin_unlock_irq(&x
->wait
.lock
);
4919 timeout
= schedule_timeout(timeout
);
4920 spin_lock_irq(&x
->wait
.lock
);
4921 } while (!x
->done
&& timeout
);
4922 __remove_wait_queue(&x
->wait
, &wait
);
4927 return timeout
?: 1;
4931 wait_for_common(struct completion
*x
, long timeout
, int state
)
4935 spin_lock_irq(&x
->wait
.lock
);
4936 timeout
= do_wait_for_common(x
, timeout
, state
);
4937 spin_unlock_irq(&x
->wait
.lock
);
4942 * wait_for_completion: - waits for completion of a task
4943 * @x: holds the state of this particular completion
4945 * This waits to be signaled for completion of a specific task. It is NOT
4946 * interruptible and there is no timeout.
4948 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4949 * and interrupt capability. Also see complete().
4951 void __sched
wait_for_completion(struct completion
*x
)
4953 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4955 EXPORT_SYMBOL(wait_for_completion
);
4958 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4959 * @x: holds the state of this particular completion
4960 * @timeout: timeout value in jiffies
4962 * This waits for either a completion of a specific task to be signaled or for a
4963 * specified timeout to expire. The timeout is in jiffies. It is not
4966 unsigned long __sched
4967 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4969 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4971 EXPORT_SYMBOL(wait_for_completion_timeout
);
4974 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4975 * @x: holds the state of this particular completion
4977 * This waits for completion of a specific task to be signaled. It is
4980 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4982 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4983 if (t
== -ERESTARTSYS
)
4987 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4990 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4991 * @x: holds the state of this particular completion
4992 * @timeout: timeout value in jiffies
4994 * This waits for either a completion of a specific task to be signaled or for a
4995 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4997 unsigned long __sched
4998 wait_for_completion_interruptible_timeout(struct completion
*x
,
4999 unsigned long timeout
)
5001 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
5003 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
5006 * wait_for_completion_killable: - waits for completion of a task (killable)
5007 * @x: holds the state of this particular completion
5009 * This waits to be signaled for completion of a specific task. It can be
5010 * interrupted by a kill signal.
5012 int __sched
wait_for_completion_killable(struct completion
*x
)
5014 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
5015 if (t
== -ERESTARTSYS
)
5019 EXPORT_SYMBOL(wait_for_completion_killable
);
5022 * try_wait_for_completion - try to decrement a completion without blocking
5023 * @x: completion structure
5025 * Returns: 0 if a decrement cannot be done without blocking
5026 * 1 if a decrement succeeded.
5028 * If a completion is being used as a counting completion,
5029 * attempt to decrement the counter without blocking. This
5030 * enables us to avoid waiting if the resource the completion
5031 * is protecting is not available.
5033 bool try_wait_for_completion(struct completion
*x
)
5037 spin_lock_irq(&x
->wait
.lock
);
5042 spin_unlock_irq(&x
->wait
.lock
);
5045 EXPORT_SYMBOL(try_wait_for_completion
);
5048 * completion_done - Test to see if a completion has any waiters
5049 * @x: completion structure
5051 * Returns: 0 if there are waiters (wait_for_completion() in progress)
5052 * 1 if there are no waiters.
5055 bool completion_done(struct completion
*x
)
5059 spin_lock_irq(&x
->wait
.lock
);
5062 spin_unlock_irq(&x
->wait
.lock
);
5065 EXPORT_SYMBOL(completion_done
);
5068 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
5070 unsigned long flags
;
5073 init_waitqueue_entry(&wait
, current
);
5075 __set_current_state(state
);
5077 spin_lock_irqsave(&q
->lock
, flags
);
5078 __add_wait_queue(q
, &wait
);
5079 spin_unlock(&q
->lock
);
5080 timeout
= schedule_timeout(timeout
);
5081 spin_lock_irq(&q
->lock
);
5082 __remove_wait_queue(q
, &wait
);
5083 spin_unlock_irqrestore(&q
->lock
, flags
);
5088 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
5090 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5092 EXPORT_SYMBOL(interruptible_sleep_on
);
5095 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5097 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
5099 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
5101 void __sched
sleep_on(wait_queue_head_t
*q
)
5103 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
5105 EXPORT_SYMBOL(sleep_on
);
5107 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
5109 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5111 EXPORT_SYMBOL(sleep_on_timeout
);
5113 #ifdef CONFIG_RT_MUTEXES
5116 * rt_mutex_setprio - set the current priority of a task
5118 * @prio: prio value (kernel-internal form)
5120 * This function changes the 'effective' priority of a task. It does
5121 * not touch ->normal_prio like __setscheduler().
5123 * Used by the rt_mutex code to implement priority inheritance logic.
5125 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
5127 unsigned long flags
;
5128 int oldprio
, on_rq
, running
;
5130 const struct sched_class
*prev_class
= p
->sched_class
;
5132 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
5134 rq
= task_rq_lock(p
, &flags
);
5135 update_rq_clock(rq
);
5138 on_rq
= p
->se
.on_rq
;
5139 running
= task_current(rq
, p
);
5141 dequeue_task(rq
, p
, 0);
5143 p
->sched_class
->put_prev_task(rq
, p
);
5146 p
->sched_class
= &rt_sched_class
;
5148 p
->sched_class
= &fair_sched_class
;
5153 p
->sched_class
->set_curr_task(rq
);
5155 enqueue_task(rq
, p
, 0);
5157 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5159 task_rq_unlock(rq
, &flags
);
5164 void set_user_nice(struct task_struct
*p
, long nice
)
5166 int old_prio
, delta
, on_rq
;
5167 unsigned long flags
;
5170 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
5173 * We have to be careful, if called from sys_setpriority(),
5174 * the task might be in the middle of scheduling on another CPU.
5176 rq
= task_rq_lock(p
, &flags
);
5177 update_rq_clock(rq
);
5179 * The RT priorities are set via sched_setscheduler(), but we still
5180 * allow the 'normal' nice value to be set - but as expected
5181 * it wont have any effect on scheduling until the task is
5182 * SCHED_FIFO/SCHED_RR:
5184 if (task_has_rt_policy(p
)) {
5185 p
->static_prio
= NICE_TO_PRIO(nice
);
5188 on_rq
= p
->se
.on_rq
;
5190 dequeue_task(rq
, p
, 0);
5192 p
->static_prio
= NICE_TO_PRIO(nice
);
5195 p
->prio
= effective_prio(p
);
5196 delta
= p
->prio
- old_prio
;
5199 enqueue_task(rq
, p
, 0);
5201 * If the task increased its priority or is running and
5202 * lowered its priority, then reschedule its CPU:
5204 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
5205 resched_task(rq
->curr
);
5208 task_rq_unlock(rq
, &flags
);
5210 EXPORT_SYMBOL(set_user_nice
);
5213 * can_nice - check if a task can reduce its nice value
5217 int can_nice(const struct task_struct
*p
, const int nice
)
5219 /* convert nice value [19,-20] to rlimit style value [1,40] */
5220 int nice_rlim
= 20 - nice
;
5222 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
5223 capable(CAP_SYS_NICE
));
5226 #ifdef __ARCH_WANT_SYS_NICE
5229 * sys_nice - change the priority of the current process.
5230 * @increment: priority increment
5232 * sys_setpriority is a more generic, but much slower function that
5233 * does similar things.
5235 SYSCALL_DEFINE1(nice
, int, increment
)
5240 * Setpriority might change our priority at the same moment.
5241 * We don't have to worry. Conceptually one call occurs first
5242 * and we have a single winner.
5244 if (increment
< -40)
5249 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
5255 if (increment
< 0 && !can_nice(current
, nice
))
5258 retval
= security_task_setnice(current
, nice
);
5262 set_user_nice(current
, nice
);
5269 * task_prio - return the priority value of a given task.
5270 * @p: the task in question.
5272 * This is the priority value as seen by users in /proc.
5273 * RT tasks are offset by -200. Normal tasks are centered
5274 * around 0, value goes from -16 to +15.
5276 int task_prio(const struct task_struct
*p
)
5278 return p
->prio
- MAX_RT_PRIO
;
5282 * task_nice - return the nice value of a given task.
5283 * @p: the task in question.
5285 int task_nice(const struct task_struct
*p
)
5287 return TASK_NICE(p
);
5289 EXPORT_SYMBOL(task_nice
);
5292 * idle_cpu - is a given cpu idle currently?
5293 * @cpu: the processor in question.
5295 int idle_cpu(int cpu
)
5297 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
5301 * idle_task - return the idle task for a given cpu.
5302 * @cpu: the processor in question.
5304 struct task_struct
*idle_task(int cpu
)
5306 return cpu_rq(cpu
)->idle
;
5310 * find_process_by_pid - find a process with a matching PID value.
5311 * @pid: the pid in question.
5313 static struct task_struct
*find_process_by_pid(pid_t pid
)
5315 return pid
? find_task_by_vpid(pid
) : current
;
5318 /* Actually do priority change: must hold rq lock. */
5320 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
5322 BUG_ON(p
->se
.on_rq
);
5325 switch (p
->policy
) {
5329 p
->sched_class
= &fair_sched_class
;
5333 p
->sched_class
= &rt_sched_class
;
5337 p
->rt_priority
= prio
;
5338 p
->normal_prio
= normal_prio(p
);
5339 /* we are holding p->pi_lock already */
5340 p
->prio
= rt_mutex_getprio(p
);
5345 * check the target process has a UID that matches the current process's
5347 static bool check_same_owner(struct task_struct
*p
)
5349 const struct cred
*cred
= current_cred(), *pcred
;
5353 pcred
= __task_cred(p
);
5354 match
= (cred
->euid
== pcred
->euid
||
5355 cred
->euid
== pcred
->uid
);
5360 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
5361 struct sched_param
*param
, bool user
)
5363 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
5364 unsigned long flags
;
5365 const struct sched_class
*prev_class
= p
->sched_class
;
5368 /* may grab non-irq protected spin_locks */
5369 BUG_ON(in_interrupt());
5371 /* double check policy once rq lock held */
5373 policy
= oldpolicy
= p
->policy
;
5374 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
5375 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
5376 policy
!= SCHED_IDLE
)
5379 * Valid priorities for SCHED_FIFO and SCHED_RR are
5380 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5381 * SCHED_BATCH and SCHED_IDLE is 0.
5383 if (param
->sched_priority
< 0 ||
5384 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
5385 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
5387 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
5391 * Allow unprivileged RT tasks to decrease priority:
5393 if (user
&& !capable(CAP_SYS_NICE
)) {
5394 if (rt_policy(policy
)) {
5395 unsigned long rlim_rtprio
;
5397 if (!lock_task_sighand(p
, &flags
))
5399 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
5400 unlock_task_sighand(p
, &flags
);
5402 /* can't set/change the rt policy */
5403 if (policy
!= p
->policy
&& !rlim_rtprio
)
5406 /* can't increase priority */
5407 if (param
->sched_priority
> p
->rt_priority
&&
5408 param
->sched_priority
> rlim_rtprio
)
5412 * Like positive nice levels, dont allow tasks to
5413 * move out of SCHED_IDLE either:
5415 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
5418 /* can't change other user's priorities */
5419 if (!check_same_owner(p
))
5424 #ifdef CONFIG_RT_GROUP_SCHED
5426 * Do not allow realtime tasks into groups that have no runtime
5429 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
5430 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
5434 retval
= security_task_setscheduler(p
, policy
, param
);
5440 * make sure no PI-waiters arrive (or leave) while we are
5441 * changing the priority of the task:
5443 spin_lock_irqsave(&p
->pi_lock
, flags
);
5445 * To be able to change p->policy safely, the apropriate
5446 * runqueue lock must be held.
5448 rq
= __task_rq_lock(p
);
5449 /* recheck policy now with rq lock held */
5450 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
5451 policy
= oldpolicy
= -1;
5452 __task_rq_unlock(rq
);
5453 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5456 update_rq_clock(rq
);
5457 on_rq
= p
->se
.on_rq
;
5458 running
= task_current(rq
, p
);
5460 deactivate_task(rq
, p
, 0);
5462 p
->sched_class
->put_prev_task(rq
, p
);
5465 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
5468 p
->sched_class
->set_curr_task(rq
);
5470 activate_task(rq
, p
, 0);
5472 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5474 __task_rq_unlock(rq
);
5475 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5477 rt_mutex_adjust_pi(p
);
5483 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5484 * @p: the task in question.
5485 * @policy: new policy.
5486 * @param: structure containing the new RT priority.
5488 * NOTE that the task may be already dead.
5490 int sched_setscheduler(struct task_struct
*p
, int policy
,
5491 struct sched_param
*param
)
5493 return __sched_setscheduler(p
, policy
, param
, true);
5495 EXPORT_SYMBOL_GPL(sched_setscheduler
);
5498 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
5499 * @p: the task in question.
5500 * @policy: new policy.
5501 * @param: structure containing the new RT priority.
5503 * Just like sched_setscheduler, only don't bother checking if the
5504 * current context has permission. For example, this is needed in
5505 * stop_machine(): we create temporary high priority worker threads,
5506 * but our caller might not have that capability.
5508 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
5509 struct sched_param
*param
)
5511 return __sched_setscheduler(p
, policy
, param
, false);
5515 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5517 struct sched_param lparam
;
5518 struct task_struct
*p
;
5521 if (!param
|| pid
< 0)
5523 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
5528 p
= find_process_by_pid(pid
);
5530 retval
= sched_setscheduler(p
, policy
, &lparam
);
5537 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5538 * @pid: the pid in question.
5539 * @policy: new policy.
5540 * @param: structure containing the new RT priority.
5542 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
5543 struct sched_param __user
*, param
)
5545 /* negative values for policy are not valid */
5549 return do_sched_setscheduler(pid
, policy
, param
);
5553 * sys_sched_setparam - set/change the RT priority of a thread
5554 * @pid: the pid in question.
5555 * @param: structure containing the new RT priority.
5557 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5559 return do_sched_setscheduler(pid
, -1, param
);
5563 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5564 * @pid: the pid in question.
5566 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
5568 struct task_struct
*p
;
5575 read_lock(&tasklist_lock
);
5576 p
= find_process_by_pid(pid
);
5578 retval
= security_task_getscheduler(p
);
5582 read_unlock(&tasklist_lock
);
5587 * sys_sched_getscheduler - get the RT priority of a thread
5588 * @pid: the pid in question.
5589 * @param: structure containing the RT priority.
5591 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
5593 struct sched_param lp
;
5594 struct task_struct
*p
;
5597 if (!param
|| pid
< 0)
5600 read_lock(&tasklist_lock
);
5601 p
= find_process_by_pid(pid
);
5606 retval
= security_task_getscheduler(p
);
5610 lp
.sched_priority
= p
->rt_priority
;
5611 read_unlock(&tasklist_lock
);
5614 * This one might sleep, we cannot do it with a spinlock held ...
5616 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
5621 read_unlock(&tasklist_lock
);
5625 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
5627 cpumask_var_t cpus_allowed
, new_mask
;
5628 struct task_struct
*p
;
5632 read_lock(&tasklist_lock
);
5634 p
= find_process_by_pid(pid
);
5636 read_unlock(&tasklist_lock
);
5642 * It is not safe to call set_cpus_allowed with the
5643 * tasklist_lock held. We will bump the task_struct's
5644 * usage count and then drop tasklist_lock.
5647 read_unlock(&tasklist_lock
);
5649 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
5653 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
5655 goto out_free_cpus_allowed
;
5658 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
5661 retval
= security_task_setscheduler(p
, 0, NULL
);
5665 cpuset_cpus_allowed(p
, cpus_allowed
);
5666 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
5668 retval
= set_cpus_allowed_ptr(p
, new_mask
);
5671 cpuset_cpus_allowed(p
, cpus_allowed
);
5672 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
5674 * We must have raced with a concurrent cpuset
5675 * update. Just reset the cpus_allowed to the
5676 * cpuset's cpus_allowed
5678 cpumask_copy(new_mask
, cpus_allowed
);
5683 free_cpumask_var(new_mask
);
5684 out_free_cpus_allowed
:
5685 free_cpumask_var(cpus_allowed
);
5692 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5693 struct cpumask
*new_mask
)
5695 if (len
< cpumask_size())
5696 cpumask_clear(new_mask
);
5697 else if (len
> cpumask_size())
5698 len
= cpumask_size();
5700 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5704 * sys_sched_setaffinity - set the cpu affinity of a process
5705 * @pid: pid of the process
5706 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5707 * @user_mask_ptr: user-space pointer to the new cpu mask
5709 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
5710 unsigned long __user
*, user_mask_ptr
)
5712 cpumask_var_t new_mask
;
5715 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
5718 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
5720 retval
= sched_setaffinity(pid
, new_mask
);
5721 free_cpumask_var(new_mask
);
5725 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
5727 struct task_struct
*p
;
5731 read_lock(&tasklist_lock
);
5734 p
= find_process_by_pid(pid
);
5738 retval
= security_task_getscheduler(p
);
5742 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
5745 read_unlock(&tasklist_lock
);
5752 * sys_sched_getaffinity - get the cpu affinity of a process
5753 * @pid: pid of the process
5754 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5755 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5757 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
5758 unsigned long __user
*, user_mask_ptr
)
5763 if (len
< cpumask_size())
5766 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
5769 ret
= sched_getaffinity(pid
, mask
);
5771 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
5774 ret
= cpumask_size();
5776 free_cpumask_var(mask
);
5782 * sys_sched_yield - yield the current processor to other threads.
5784 * This function yields the current CPU to other tasks. If there are no
5785 * other threads running on this CPU then this function will return.
5787 SYSCALL_DEFINE0(sched_yield
)
5789 struct rq
*rq
= this_rq_lock();
5791 schedstat_inc(rq
, yld_count
);
5792 current
->sched_class
->yield_task(rq
);
5795 * Since we are going to call schedule() anyway, there's
5796 * no need to preempt or enable interrupts:
5798 __release(rq
->lock
);
5799 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5800 _raw_spin_unlock(&rq
->lock
);
5801 preempt_enable_no_resched();
5808 static void __cond_resched(void)
5810 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5811 __might_sleep(__FILE__
, __LINE__
);
5814 * The BKS might be reacquired before we have dropped
5815 * PREEMPT_ACTIVE, which could trigger a second
5816 * cond_resched() call.
5819 add_preempt_count(PREEMPT_ACTIVE
);
5821 sub_preempt_count(PREEMPT_ACTIVE
);
5822 } while (need_resched());
5825 int __sched
_cond_resched(void)
5827 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5828 system_state
== SYSTEM_RUNNING
) {
5834 EXPORT_SYMBOL(_cond_resched
);
5837 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5838 * call schedule, and on return reacquire the lock.
5840 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5841 * operations here to prevent schedule() from being called twice (once via
5842 * spin_unlock(), once by hand).
5844 int cond_resched_lock(spinlock_t
*lock
)
5846 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5849 if (spin_needbreak(lock
) || resched
) {
5851 if (resched
&& need_resched())
5860 EXPORT_SYMBOL(cond_resched_lock
);
5862 int __sched
cond_resched_softirq(void)
5864 BUG_ON(!in_softirq());
5866 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5874 EXPORT_SYMBOL(cond_resched_softirq
);
5877 * yield - yield the current processor to other threads.
5879 * This is a shortcut for kernel-space yielding - it marks the
5880 * thread runnable and calls sys_sched_yield().
5882 void __sched
yield(void)
5884 set_current_state(TASK_RUNNING
);
5887 EXPORT_SYMBOL(yield
);
5890 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5891 * that process accounting knows that this is a task in IO wait state.
5893 * But don't do that if it is a deliberate, throttling IO wait (this task
5894 * has set its backing_dev_info: the queue against which it should throttle)
5896 void __sched
io_schedule(void)
5898 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5900 delayacct_blkio_start();
5901 atomic_inc(&rq
->nr_iowait
);
5903 atomic_dec(&rq
->nr_iowait
);
5904 delayacct_blkio_end();
5906 EXPORT_SYMBOL(io_schedule
);
5908 long __sched
io_schedule_timeout(long timeout
)
5910 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5913 delayacct_blkio_start();
5914 atomic_inc(&rq
->nr_iowait
);
5915 ret
= schedule_timeout(timeout
);
5916 atomic_dec(&rq
->nr_iowait
);
5917 delayacct_blkio_end();
5922 * sys_sched_get_priority_max - return maximum RT priority.
5923 * @policy: scheduling class.
5925 * this syscall returns the maximum rt_priority that can be used
5926 * by a given scheduling class.
5928 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
5935 ret
= MAX_USER_RT_PRIO
-1;
5947 * sys_sched_get_priority_min - return minimum RT priority.
5948 * @policy: scheduling class.
5950 * this syscall returns the minimum rt_priority that can be used
5951 * by a given scheduling class.
5953 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
5971 * sys_sched_rr_get_interval - return the default timeslice of a process.
5972 * @pid: pid of the process.
5973 * @interval: userspace pointer to the timeslice value.
5975 * this syscall writes the default timeslice value of a given process
5976 * into the user-space timespec buffer. A value of '0' means infinity.
5978 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
5979 struct timespec __user
*, interval
)
5981 struct task_struct
*p
;
5982 unsigned int time_slice
;
5990 read_lock(&tasklist_lock
);
5991 p
= find_process_by_pid(pid
);
5995 retval
= security_task_getscheduler(p
);
6000 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
6001 * tasks that are on an otherwise idle runqueue:
6004 if (p
->policy
== SCHED_RR
) {
6005 time_slice
= DEF_TIMESLICE
;
6006 } else if (p
->policy
!= SCHED_FIFO
) {
6007 struct sched_entity
*se
= &p
->se
;
6008 unsigned long flags
;
6011 rq
= task_rq_lock(p
, &flags
);
6012 if (rq
->cfs
.load
.weight
)
6013 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
6014 task_rq_unlock(rq
, &flags
);
6016 read_unlock(&tasklist_lock
);
6017 jiffies_to_timespec(time_slice
, &t
);
6018 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
6022 read_unlock(&tasklist_lock
);
6026 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
6028 void sched_show_task(struct task_struct
*p
)
6030 unsigned long free
= 0;
6033 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
6034 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
6035 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
6036 #if BITS_PER_LONG == 32
6037 if (state
== TASK_RUNNING
)
6038 printk(KERN_CONT
" running ");
6040 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
6042 if (state
== TASK_RUNNING
)
6043 printk(KERN_CONT
" running task ");
6045 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
6047 #ifdef CONFIG_DEBUG_STACK_USAGE
6049 unsigned long *n
= end_of_stack(p
);
6052 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
6055 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
6056 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
6058 show_stack(p
, NULL
);
6061 void show_state_filter(unsigned long state_filter
)
6063 struct task_struct
*g
, *p
;
6065 #if BITS_PER_LONG == 32
6067 " task PC stack pid father\n");
6070 " task PC stack pid father\n");
6072 read_lock(&tasklist_lock
);
6073 do_each_thread(g
, p
) {
6075 * reset the NMI-timeout, listing all files on a slow
6076 * console might take alot of time:
6078 touch_nmi_watchdog();
6079 if (!state_filter
|| (p
->state
& state_filter
))
6081 } while_each_thread(g
, p
);
6083 touch_all_softlockup_watchdogs();
6085 #ifdef CONFIG_SCHED_DEBUG
6086 sysrq_sched_debug_show();
6088 read_unlock(&tasklist_lock
);
6090 * Only show locks if all tasks are dumped:
6092 if (state_filter
== -1)
6093 debug_show_all_locks();
6096 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
6098 idle
->sched_class
= &idle_sched_class
;
6102 * init_idle - set up an idle thread for a given CPU
6103 * @idle: task in question
6104 * @cpu: cpu the idle task belongs to
6106 * NOTE: this function does not set the idle thread's NEED_RESCHED
6107 * flag, to make booting more robust.
6109 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
6111 struct rq
*rq
= cpu_rq(cpu
);
6112 unsigned long flags
;
6114 spin_lock_irqsave(&rq
->lock
, flags
);
6117 idle
->se
.exec_start
= sched_clock();
6119 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
6120 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
6121 __set_task_cpu(idle
, cpu
);
6123 rq
->curr
= rq
->idle
= idle
;
6124 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
6127 spin_unlock_irqrestore(&rq
->lock
, flags
);
6129 /* Set the preempt count _outside_ the spinlocks! */
6130 #if defined(CONFIG_PREEMPT)
6131 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
6133 task_thread_info(idle
)->preempt_count
= 0;
6136 * The idle tasks have their own, simple scheduling class:
6138 idle
->sched_class
= &idle_sched_class
;
6139 ftrace_graph_init_task(idle
);
6143 * In a system that switches off the HZ timer nohz_cpu_mask
6144 * indicates which cpus entered this state. This is used
6145 * in the rcu update to wait only for active cpus. For system
6146 * which do not switch off the HZ timer nohz_cpu_mask should
6147 * always be CPU_BITS_NONE.
6149 cpumask_var_t nohz_cpu_mask
;
6152 * Increase the granularity value when there are more CPUs,
6153 * because with more CPUs the 'effective latency' as visible
6154 * to users decreases. But the relationship is not linear,
6155 * so pick a second-best guess by going with the log2 of the
6158 * This idea comes from the SD scheduler of Con Kolivas:
6160 static inline void sched_init_granularity(void)
6162 unsigned int factor
= 1 + ilog2(num_online_cpus());
6163 const unsigned long limit
= 200000000;
6165 sysctl_sched_min_granularity
*= factor
;
6166 if (sysctl_sched_min_granularity
> limit
)
6167 sysctl_sched_min_granularity
= limit
;
6169 sysctl_sched_latency
*= factor
;
6170 if (sysctl_sched_latency
> limit
)
6171 sysctl_sched_latency
= limit
;
6173 sysctl_sched_wakeup_granularity
*= factor
;
6175 sysctl_sched_shares_ratelimit
*= factor
;
6180 * This is how migration works:
6182 * 1) we queue a struct migration_req structure in the source CPU's
6183 * runqueue and wake up that CPU's migration thread.
6184 * 2) we down() the locked semaphore => thread blocks.
6185 * 3) migration thread wakes up (implicitly it forces the migrated
6186 * thread off the CPU)
6187 * 4) it gets the migration request and checks whether the migrated
6188 * task is still in the wrong runqueue.
6189 * 5) if it's in the wrong runqueue then the migration thread removes
6190 * it and puts it into the right queue.
6191 * 6) migration thread up()s the semaphore.
6192 * 7) we wake up and the migration is done.
6196 * Change a given task's CPU affinity. Migrate the thread to a
6197 * proper CPU and schedule it away if the CPU it's executing on
6198 * is removed from the allowed bitmask.
6200 * NOTE: the caller must have a valid reference to the task, the
6201 * task must not exit() & deallocate itself prematurely. The
6202 * call is not atomic; no spinlocks may be held.
6204 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
6206 struct migration_req req
;
6207 unsigned long flags
;
6211 rq
= task_rq_lock(p
, &flags
);
6212 if (!cpumask_intersects(new_mask
, cpu_online_mask
)) {
6217 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
6218 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
6223 if (p
->sched_class
->set_cpus_allowed
)
6224 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
6226 cpumask_copy(&p
->cpus_allowed
, new_mask
);
6227 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
6230 /* Can the task run on the task's current CPU? If so, we're done */
6231 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
6234 if (migrate_task(p
, cpumask_any_and(cpu_online_mask
, new_mask
), &req
)) {
6235 /* Need help from migration thread: drop lock and wait. */
6236 task_rq_unlock(rq
, &flags
);
6237 wake_up_process(rq
->migration_thread
);
6238 wait_for_completion(&req
.done
);
6239 tlb_migrate_finish(p
->mm
);
6243 task_rq_unlock(rq
, &flags
);
6247 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
6250 * Move (not current) task off this cpu, onto dest cpu. We're doing
6251 * this because either it can't run here any more (set_cpus_allowed()
6252 * away from this CPU, or CPU going down), or because we're
6253 * attempting to rebalance this task on exec (sched_exec).
6255 * So we race with normal scheduler movements, but that's OK, as long
6256 * as the task is no longer on this CPU.
6258 * Returns non-zero if task was successfully migrated.
6260 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6262 struct rq
*rq_dest
, *rq_src
;
6265 if (unlikely(!cpu_active(dest_cpu
)))
6268 rq_src
= cpu_rq(src_cpu
);
6269 rq_dest
= cpu_rq(dest_cpu
);
6271 double_rq_lock(rq_src
, rq_dest
);
6272 /* Already moved. */
6273 if (task_cpu(p
) != src_cpu
)
6275 /* Affinity changed (again). */
6276 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6279 on_rq
= p
->se
.on_rq
;
6281 deactivate_task(rq_src
, p
, 0);
6283 set_task_cpu(p
, dest_cpu
);
6285 activate_task(rq_dest
, p
, 0);
6286 check_preempt_curr(rq_dest
, p
, 0);
6291 double_rq_unlock(rq_src
, rq_dest
);
6296 * migration_thread - this is a highprio system thread that performs
6297 * thread migration by bumping thread off CPU then 'pushing' onto
6300 static int migration_thread(void *data
)
6302 int cpu
= (long)data
;
6306 BUG_ON(rq
->migration_thread
!= current
);
6308 set_current_state(TASK_INTERRUPTIBLE
);
6309 while (!kthread_should_stop()) {
6310 struct migration_req
*req
;
6311 struct list_head
*head
;
6313 spin_lock_irq(&rq
->lock
);
6315 if (cpu_is_offline(cpu
)) {
6316 spin_unlock_irq(&rq
->lock
);
6320 if (rq
->active_balance
) {
6321 active_load_balance(rq
, cpu
);
6322 rq
->active_balance
= 0;
6325 head
= &rq
->migration_queue
;
6327 if (list_empty(head
)) {
6328 spin_unlock_irq(&rq
->lock
);
6330 set_current_state(TASK_INTERRUPTIBLE
);
6333 req
= list_entry(head
->next
, struct migration_req
, list
);
6334 list_del_init(head
->next
);
6336 spin_unlock(&rq
->lock
);
6337 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
6340 complete(&req
->done
);
6342 __set_current_state(TASK_RUNNING
);
6346 /* Wait for kthread_stop */
6347 set_current_state(TASK_INTERRUPTIBLE
);
6348 while (!kthread_should_stop()) {
6350 set_current_state(TASK_INTERRUPTIBLE
);
6352 __set_current_state(TASK_RUNNING
);
6356 #ifdef CONFIG_HOTPLUG_CPU
6358 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6362 local_irq_disable();
6363 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
6369 * Figure out where task on dead CPU should go, use force if necessary.
6371 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
6374 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(dead_cpu
));
6377 /* Look for allowed, online CPU in same node. */
6378 for_each_cpu_and(dest_cpu
, nodemask
, cpu_online_mask
)
6379 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
6382 /* Any allowed, online CPU? */
6383 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_online_mask
);
6384 if (dest_cpu
< nr_cpu_ids
)
6387 /* No more Mr. Nice Guy. */
6388 if (dest_cpu
>= nr_cpu_ids
) {
6389 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
6390 dest_cpu
= cpumask_any_and(cpu_online_mask
, &p
->cpus_allowed
);
6393 * Don't tell them about moving exiting tasks or
6394 * kernel threads (both mm NULL), since they never
6397 if (p
->mm
&& printk_ratelimit()) {
6398 printk(KERN_INFO
"process %d (%s) no "
6399 "longer affine to cpu%d\n",
6400 task_pid_nr(p
), p
->comm
, dead_cpu
);
6405 /* It can have affinity changed while we were choosing. */
6406 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
6411 * While a dead CPU has no uninterruptible tasks queued at this point,
6412 * it might still have a nonzero ->nr_uninterruptible counter, because
6413 * for performance reasons the counter is not stricly tracking tasks to
6414 * their home CPUs. So we just add the counter to another CPU's counter,
6415 * to keep the global sum constant after CPU-down:
6417 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6419 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_online_mask
));
6420 unsigned long flags
;
6422 local_irq_save(flags
);
6423 double_rq_lock(rq_src
, rq_dest
);
6424 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6425 rq_src
->nr_uninterruptible
= 0;
6426 double_rq_unlock(rq_src
, rq_dest
);
6427 local_irq_restore(flags
);
6430 /* Run through task list and migrate tasks from the dead cpu. */
6431 static void migrate_live_tasks(int src_cpu
)
6433 struct task_struct
*p
, *t
;
6435 read_lock(&tasklist_lock
);
6437 do_each_thread(t
, p
) {
6441 if (task_cpu(p
) == src_cpu
)
6442 move_task_off_dead_cpu(src_cpu
, p
);
6443 } while_each_thread(t
, p
);
6445 read_unlock(&tasklist_lock
);
6449 * Schedules idle task to be the next runnable task on current CPU.
6450 * It does so by boosting its priority to highest possible.
6451 * Used by CPU offline code.
6453 void sched_idle_next(void)
6455 int this_cpu
= smp_processor_id();
6456 struct rq
*rq
= cpu_rq(this_cpu
);
6457 struct task_struct
*p
= rq
->idle
;
6458 unsigned long flags
;
6460 /* cpu has to be offline */
6461 BUG_ON(cpu_online(this_cpu
));
6464 * Strictly not necessary since rest of the CPUs are stopped by now
6465 * and interrupts disabled on the current cpu.
6467 spin_lock_irqsave(&rq
->lock
, flags
);
6469 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6471 update_rq_clock(rq
);
6472 activate_task(rq
, p
, 0);
6474 spin_unlock_irqrestore(&rq
->lock
, flags
);
6478 * Ensures that the idle task is using init_mm right before its cpu goes
6481 void idle_task_exit(void)
6483 struct mm_struct
*mm
= current
->active_mm
;
6485 BUG_ON(cpu_online(smp_processor_id()));
6488 switch_mm(mm
, &init_mm
, current
);
6492 /* called under rq->lock with disabled interrupts */
6493 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
6495 struct rq
*rq
= cpu_rq(dead_cpu
);
6497 /* Must be exiting, otherwise would be on tasklist. */
6498 BUG_ON(!p
->exit_state
);
6500 /* Cannot have done final schedule yet: would have vanished. */
6501 BUG_ON(p
->state
== TASK_DEAD
);
6506 * Drop lock around migration; if someone else moves it,
6507 * that's OK. No task can be added to this CPU, so iteration is
6510 spin_unlock_irq(&rq
->lock
);
6511 move_task_off_dead_cpu(dead_cpu
, p
);
6512 spin_lock_irq(&rq
->lock
);
6517 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6518 static void migrate_dead_tasks(unsigned int dead_cpu
)
6520 struct rq
*rq
= cpu_rq(dead_cpu
);
6521 struct task_struct
*next
;
6524 if (!rq
->nr_running
)
6526 update_rq_clock(rq
);
6527 next
= pick_next_task(rq
, rq
->curr
);
6530 next
->sched_class
->put_prev_task(rq
, next
);
6531 migrate_dead(dead_cpu
, next
);
6535 #endif /* CONFIG_HOTPLUG_CPU */
6537 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6539 static struct ctl_table sd_ctl_dir
[] = {
6541 .procname
= "sched_domain",
6547 static struct ctl_table sd_ctl_root
[] = {
6549 .ctl_name
= CTL_KERN
,
6550 .procname
= "kernel",
6552 .child
= sd_ctl_dir
,
6557 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
6559 struct ctl_table
*entry
=
6560 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
6565 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
6567 struct ctl_table
*entry
;
6570 * In the intermediate directories, both the child directory and
6571 * procname are dynamically allocated and could fail but the mode
6572 * will always be set. In the lowest directory the names are
6573 * static strings and all have proc handlers.
6575 for (entry
= *tablep
; entry
->mode
; entry
++) {
6577 sd_free_ctl_entry(&entry
->child
);
6578 if (entry
->proc_handler
== NULL
)
6579 kfree(entry
->procname
);
6587 set_table_entry(struct ctl_table
*entry
,
6588 const char *procname
, void *data
, int maxlen
,
6589 mode_t mode
, proc_handler
*proc_handler
)
6591 entry
->procname
= procname
;
6593 entry
->maxlen
= maxlen
;
6595 entry
->proc_handler
= proc_handler
;
6598 static struct ctl_table
*
6599 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
6601 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
6606 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
6607 sizeof(long), 0644, proc_doulongvec_minmax
);
6608 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
6609 sizeof(long), 0644, proc_doulongvec_minmax
);
6610 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
6611 sizeof(int), 0644, proc_dointvec_minmax
);
6612 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
6613 sizeof(int), 0644, proc_dointvec_minmax
);
6614 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
6615 sizeof(int), 0644, proc_dointvec_minmax
);
6616 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
6617 sizeof(int), 0644, proc_dointvec_minmax
);
6618 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
6619 sizeof(int), 0644, proc_dointvec_minmax
);
6620 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
6621 sizeof(int), 0644, proc_dointvec_minmax
);
6622 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
6623 sizeof(int), 0644, proc_dointvec_minmax
);
6624 set_table_entry(&table
[9], "cache_nice_tries",
6625 &sd
->cache_nice_tries
,
6626 sizeof(int), 0644, proc_dointvec_minmax
);
6627 set_table_entry(&table
[10], "flags", &sd
->flags
,
6628 sizeof(int), 0644, proc_dointvec_minmax
);
6629 set_table_entry(&table
[11], "name", sd
->name
,
6630 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
6631 /* &table[12] is terminator */
6636 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
6638 struct ctl_table
*entry
, *table
;
6639 struct sched_domain
*sd
;
6640 int domain_num
= 0, i
;
6643 for_each_domain(cpu
, sd
)
6645 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6650 for_each_domain(cpu
, sd
) {
6651 snprintf(buf
, 32, "domain%d", i
);
6652 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6654 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6661 static struct ctl_table_header
*sd_sysctl_header
;
6662 static void register_sched_domain_sysctl(void)
6664 int i
, cpu_num
= num_online_cpus();
6665 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6668 WARN_ON(sd_ctl_dir
[0].child
);
6669 sd_ctl_dir
[0].child
= entry
;
6674 for_each_online_cpu(i
) {
6675 snprintf(buf
, 32, "cpu%d", i
);
6676 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6678 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6682 WARN_ON(sd_sysctl_header
);
6683 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6686 /* may be called multiple times per register */
6687 static void unregister_sched_domain_sysctl(void)
6689 if (sd_sysctl_header
)
6690 unregister_sysctl_table(sd_sysctl_header
);
6691 sd_sysctl_header
= NULL
;
6692 if (sd_ctl_dir
[0].child
)
6693 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6696 static void register_sched_domain_sysctl(void)
6699 static void unregister_sched_domain_sysctl(void)
6704 static void set_rq_online(struct rq
*rq
)
6707 const struct sched_class
*class;
6709 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
6712 for_each_class(class) {
6713 if (class->rq_online
)
6714 class->rq_online(rq
);
6719 static void set_rq_offline(struct rq
*rq
)
6722 const struct sched_class
*class;
6724 for_each_class(class) {
6725 if (class->rq_offline
)
6726 class->rq_offline(rq
);
6729 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
6735 * migration_call - callback that gets triggered when a CPU is added.
6736 * Here we can start up the necessary migration thread for the new CPU.
6738 static int __cpuinit
6739 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6741 struct task_struct
*p
;
6742 int cpu
= (long)hcpu
;
6743 unsigned long flags
;
6748 case CPU_UP_PREPARE
:
6749 case CPU_UP_PREPARE_FROZEN
:
6750 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6753 kthread_bind(p
, cpu
);
6754 /* Must be high prio: stop_machine expects to yield to it. */
6755 rq
= task_rq_lock(p
, &flags
);
6756 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6757 task_rq_unlock(rq
, &flags
);
6758 cpu_rq(cpu
)->migration_thread
= p
;
6762 case CPU_ONLINE_FROZEN
:
6763 /* Strictly unnecessary, as first user will wake it. */
6764 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6766 /* Update our root-domain */
6768 spin_lock_irqsave(&rq
->lock
, flags
);
6770 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6774 spin_unlock_irqrestore(&rq
->lock
, flags
);
6777 #ifdef CONFIG_HOTPLUG_CPU
6778 case CPU_UP_CANCELED
:
6779 case CPU_UP_CANCELED_FROZEN
:
6780 if (!cpu_rq(cpu
)->migration_thread
)
6782 /* Unbind it from offline cpu so it can run. Fall thru. */
6783 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6784 cpumask_any(cpu_online_mask
));
6785 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6786 cpu_rq(cpu
)->migration_thread
= NULL
;
6790 case CPU_DEAD_FROZEN
:
6791 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6792 migrate_live_tasks(cpu
);
6794 kthread_stop(rq
->migration_thread
);
6795 rq
->migration_thread
= NULL
;
6796 /* Idle task back to normal (off runqueue, low prio) */
6797 spin_lock_irq(&rq
->lock
);
6798 update_rq_clock(rq
);
6799 deactivate_task(rq
, rq
->idle
, 0);
6800 rq
->idle
->static_prio
= MAX_PRIO
;
6801 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6802 rq
->idle
->sched_class
= &idle_sched_class
;
6803 migrate_dead_tasks(cpu
);
6804 spin_unlock_irq(&rq
->lock
);
6806 migrate_nr_uninterruptible(rq
);
6807 BUG_ON(rq
->nr_running
!= 0);
6810 * No need to migrate the tasks: it was best-effort if
6811 * they didn't take sched_hotcpu_mutex. Just wake up
6814 spin_lock_irq(&rq
->lock
);
6815 while (!list_empty(&rq
->migration_queue
)) {
6816 struct migration_req
*req
;
6818 req
= list_entry(rq
->migration_queue
.next
,
6819 struct migration_req
, list
);
6820 list_del_init(&req
->list
);
6821 spin_unlock_irq(&rq
->lock
);
6822 complete(&req
->done
);
6823 spin_lock_irq(&rq
->lock
);
6825 spin_unlock_irq(&rq
->lock
);
6829 case CPU_DYING_FROZEN
:
6830 /* Update our root-domain */
6832 spin_lock_irqsave(&rq
->lock
, flags
);
6834 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
6837 spin_unlock_irqrestore(&rq
->lock
, flags
);
6844 /* Register at highest priority so that task migration (migrate_all_tasks)
6845 * happens before everything else.
6847 static struct notifier_block __cpuinitdata migration_notifier
= {
6848 .notifier_call
= migration_call
,
6852 static int __init
migration_init(void)
6854 void *cpu
= (void *)(long)smp_processor_id();
6857 /* Start one for the boot CPU: */
6858 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6859 BUG_ON(err
== NOTIFY_BAD
);
6860 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6861 register_cpu_notifier(&migration_notifier
);
6865 early_initcall(migration_init
);
6870 #ifdef CONFIG_SCHED_DEBUG
6872 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6873 struct cpumask
*groupmask
)
6875 struct sched_group
*group
= sd
->groups
;
6878 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
6879 cpumask_clear(groupmask
);
6881 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6883 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6884 printk("does not load-balance\n");
6886 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6891 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
6893 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
6894 printk(KERN_ERR
"ERROR: domain->span does not contain "
6897 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6898 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6902 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6906 printk(KERN_ERR
"ERROR: group is NULL\n");
6910 if (!group
->__cpu_power
) {
6911 printk(KERN_CONT
"\n");
6912 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6917 if (!cpumask_weight(sched_group_cpus(group
))) {
6918 printk(KERN_CONT
"\n");
6919 printk(KERN_ERR
"ERROR: empty group\n");
6923 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6924 printk(KERN_CONT
"\n");
6925 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6929 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6931 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6932 printk(KERN_CONT
" %s", str
);
6934 group
= group
->next
;
6935 } while (group
!= sd
->groups
);
6936 printk(KERN_CONT
"\n");
6938 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6939 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6942 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6943 printk(KERN_ERR
"ERROR: parent span is not a superset "
6944 "of domain->span\n");
6948 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6950 cpumask_var_t groupmask
;
6954 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6958 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6960 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
6961 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6966 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6973 free_cpumask_var(groupmask
);
6975 #else /* !CONFIG_SCHED_DEBUG */
6976 # define sched_domain_debug(sd, cpu) do { } while (0)
6977 #endif /* CONFIG_SCHED_DEBUG */
6979 static int sd_degenerate(struct sched_domain
*sd
)
6981 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6984 /* Following flags need at least 2 groups */
6985 if (sd
->flags
& (SD_LOAD_BALANCE
|
6986 SD_BALANCE_NEWIDLE
|
6990 SD_SHARE_PKG_RESOURCES
)) {
6991 if (sd
->groups
!= sd
->groups
->next
)
6995 /* Following flags don't use groups */
6996 if (sd
->flags
& (SD_WAKE_IDLE
|
7005 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
7007 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
7009 if (sd_degenerate(parent
))
7012 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
7015 /* Does parent contain flags not in child? */
7016 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
7017 if (cflags
& SD_WAKE_AFFINE
)
7018 pflags
&= ~SD_WAKE_BALANCE
;
7019 /* Flags needing groups don't count if only 1 group in parent */
7020 if (parent
->groups
== parent
->groups
->next
) {
7021 pflags
&= ~(SD_LOAD_BALANCE
|
7022 SD_BALANCE_NEWIDLE
|
7026 SD_SHARE_PKG_RESOURCES
);
7027 if (nr_node_ids
== 1)
7028 pflags
&= ~SD_SERIALIZE
;
7030 if (~cflags
& pflags
)
7036 static void free_rootdomain(struct root_domain
*rd
)
7038 cpupri_cleanup(&rd
->cpupri
);
7040 free_cpumask_var(rd
->rto_mask
);
7041 free_cpumask_var(rd
->online
);
7042 free_cpumask_var(rd
->span
);
7046 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
7048 unsigned long flags
;
7050 spin_lock_irqsave(&rq
->lock
, flags
);
7053 struct root_domain
*old_rd
= rq
->rd
;
7055 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
7058 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
7060 if (atomic_dec_and_test(&old_rd
->refcount
))
7061 free_rootdomain(old_rd
);
7064 atomic_inc(&rd
->refcount
);
7067 cpumask_set_cpu(rq
->cpu
, rd
->span
);
7068 if (cpumask_test_cpu(rq
->cpu
, cpu_online_mask
))
7071 spin_unlock_irqrestore(&rq
->lock
, flags
);
7074 static int __init_refok
init_rootdomain(struct root_domain
*rd
, bool bootmem
)
7076 memset(rd
, 0, sizeof(*rd
));
7079 alloc_bootmem_cpumask_var(&def_root_domain
.span
);
7080 alloc_bootmem_cpumask_var(&def_root_domain
.online
);
7081 alloc_bootmem_cpumask_var(&def_root_domain
.rto_mask
);
7082 cpupri_init(&rd
->cpupri
, true);
7086 if (!alloc_cpumask_var(&rd
->span
, GFP_KERNEL
))
7088 if (!alloc_cpumask_var(&rd
->online
, GFP_KERNEL
))
7090 if (!alloc_cpumask_var(&rd
->rto_mask
, GFP_KERNEL
))
7093 if (cpupri_init(&rd
->cpupri
, false) != 0)
7098 free_cpumask_var(rd
->rto_mask
);
7100 free_cpumask_var(rd
->online
);
7102 free_cpumask_var(rd
->span
);
7107 static void init_defrootdomain(void)
7109 init_rootdomain(&def_root_domain
, true);
7111 atomic_set(&def_root_domain
.refcount
, 1);
7114 static struct root_domain
*alloc_rootdomain(void)
7116 struct root_domain
*rd
;
7118 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
7122 if (init_rootdomain(rd
, false) != 0) {
7131 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
7132 * hold the hotplug lock.
7135 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
7137 struct rq
*rq
= cpu_rq(cpu
);
7138 struct sched_domain
*tmp
;
7140 /* Remove the sched domains which do not contribute to scheduling. */
7141 for (tmp
= sd
; tmp
; ) {
7142 struct sched_domain
*parent
= tmp
->parent
;
7146 if (sd_parent_degenerate(tmp
, parent
)) {
7147 tmp
->parent
= parent
->parent
;
7149 parent
->parent
->child
= tmp
;
7154 if (sd
&& sd_degenerate(sd
)) {
7160 sched_domain_debug(sd
, cpu
);
7162 rq_attach_root(rq
, rd
);
7163 rcu_assign_pointer(rq
->sd
, sd
);
7166 /* cpus with isolated domains */
7167 static cpumask_var_t cpu_isolated_map
;
7169 /* Setup the mask of cpus configured for isolated domains */
7170 static int __init
isolated_cpu_setup(char *str
)
7172 cpulist_parse(str
, cpu_isolated_map
);
7176 __setup("isolcpus=", isolated_cpu_setup
);
7179 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
7180 * to a function which identifies what group(along with sched group) a CPU
7181 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
7182 * (due to the fact that we keep track of groups covered with a struct cpumask).
7184 * init_sched_build_groups will build a circular linked list of the groups
7185 * covered by the given span, and will set each group's ->cpumask correctly,
7186 * and ->cpu_power to 0.
7189 init_sched_build_groups(const struct cpumask
*span
,
7190 const struct cpumask
*cpu_map
,
7191 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
7192 struct sched_group
**sg
,
7193 struct cpumask
*tmpmask
),
7194 struct cpumask
*covered
, struct cpumask
*tmpmask
)
7196 struct sched_group
*first
= NULL
, *last
= NULL
;
7199 cpumask_clear(covered
);
7201 for_each_cpu(i
, span
) {
7202 struct sched_group
*sg
;
7203 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
7206 if (cpumask_test_cpu(i
, covered
))
7209 cpumask_clear(sched_group_cpus(sg
));
7210 sg
->__cpu_power
= 0;
7212 for_each_cpu(j
, span
) {
7213 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
7216 cpumask_set_cpu(j
, covered
);
7217 cpumask_set_cpu(j
, sched_group_cpus(sg
));
7228 #define SD_NODES_PER_DOMAIN 16
7233 * find_next_best_node - find the next node to include in a sched_domain
7234 * @node: node whose sched_domain we're building
7235 * @used_nodes: nodes already in the sched_domain
7237 * Find the next node to include in a given scheduling domain. Simply
7238 * finds the closest node not already in the @used_nodes map.
7240 * Should use nodemask_t.
7242 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
7244 int i
, n
, val
, min_val
, best_node
= 0;
7248 for (i
= 0; i
< nr_node_ids
; i
++) {
7249 /* Start at @node */
7250 n
= (node
+ i
) % nr_node_ids
;
7252 if (!nr_cpus_node(n
))
7255 /* Skip already used nodes */
7256 if (node_isset(n
, *used_nodes
))
7259 /* Simple min distance search */
7260 val
= node_distance(node
, n
);
7262 if (val
< min_val
) {
7268 node_set(best_node
, *used_nodes
);
7273 * sched_domain_node_span - get a cpumask for a node's sched_domain
7274 * @node: node whose cpumask we're constructing
7275 * @span: resulting cpumask
7277 * Given a node, construct a good cpumask for its sched_domain to span. It
7278 * should be one that prevents unnecessary balancing, but also spreads tasks
7281 static void sched_domain_node_span(int node
, struct cpumask
*span
)
7283 nodemask_t used_nodes
;
7286 cpumask_clear(span
);
7287 nodes_clear(used_nodes
);
7289 cpumask_or(span
, span
, cpumask_of_node(node
));
7290 node_set(node
, used_nodes
);
7292 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
7293 int next_node
= find_next_best_node(node
, &used_nodes
);
7295 cpumask_or(span
, span
, cpumask_of_node(next_node
));
7298 #endif /* CONFIG_NUMA */
7300 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
7303 * The cpus mask in sched_group and sched_domain hangs off the end.
7304 * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
7305 * for nr_cpu_ids < CONFIG_NR_CPUS.
7307 struct static_sched_group
{
7308 struct sched_group sg
;
7309 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
7312 struct static_sched_domain
{
7313 struct sched_domain sd
;
7314 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
7318 * SMT sched-domains:
7320 #ifdef CONFIG_SCHED_SMT
7321 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
7322 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_cpus
);
7325 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
7326 struct sched_group
**sg
, struct cpumask
*unused
)
7329 *sg
= &per_cpu(sched_group_cpus
, cpu
).sg
;
7332 #endif /* CONFIG_SCHED_SMT */
7335 * multi-core sched-domains:
7337 #ifdef CONFIG_SCHED_MC
7338 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
7339 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
7340 #endif /* CONFIG_SCHED_MC */
7342 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7344 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
7345 struct sched_group
**sg
, struct cpumask
*mask
)
7349 cpumask_and(mask
, &per_cpu(cpu_sibling_map
, cpu
), cpu_map
);
7350 group
= cpumask_first(mask
);
7352 *sg
= &per_cpu(sched_group_core
, group
).sg
;
7355 #elif defined(CONFIG_SCHED_MC)
7357 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
7358 struct sched_group
**sg
, struct cpumask
*unused
)
7361 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
7366 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
7367 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
7370 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
7371 struct sched_group
**sg
, struct cpumask
*mask
)
7374 #ifdef CONFIG_SCHED_MC
7375 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
7376 group
= cpumask_first(mask
);
7377 #elif defined(CONFIG_SCHED_SMT)
7378 cpumask_and(mask
, &per_cpu(cpu_sibling_map
, cpu
), cpu_map
);
7379 group
= cpumask_first(mask
);
7384 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
7390 * The init_sched_build_groups can't handle what we want to do with node
7391 * groups, so roll our own. Now each node has its own list of groups which
7392 * gets dynamically allocated.
7394 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
7395 static struct sched_group
***sched_group_nodes_bycpu
;
7397 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
7398 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
7400 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
7401 struct sched_group
**sg
,
7402 struct cpumask
*nodemask
)
7406 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
7407 group
= cpumask_first(nodemask
);
7410 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
7414 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
7416 struct sched_group
*sg
= group_head
;
7422 for_each_cpu(j
, sched_group_cpus(sg
)) {
7423 struct sched_domain
*sd
;
7425 sd
= &per_cpu(phys_domains
, j
).sd
;
7426 if (j
!= cpumask_first(sched_group_cpus(sd
->groups
))) {
7428 * Only add "power" once for each
7434 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
7437 } while (sg
!= group_head
);
7439 #endif /* CONFIG_NUMA */
7442 /* Free memory allocated for various sched_group structures */
7443 static void free_sched_groups(const struct cpumask
*cpu_map
,
7444 struct cpumask
*nodemask
)
7448 for_each_cpu(cpu
, cpu_map
) {
7449 struct sched_group
**sched_group_nodes
7450 = sched_group_nodes_bycpu
[cpu
];
7452 if (!sched_group_nodes
)
7455 for (i
= 0; i
< nr_node_ids
; i
++) {
7456 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
7458 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
7459 if (cpumask_empty(nodemask
))
7469 if (oldsg
!= sched_group_nodes
[i
])
7472 kfree(sched_group_nodes
);
7473 sched_group_nodes_bycpu
[cpu
] = NULL
;
7476 #else /* !CONFIG_NUMA */
7477 static void free_sched_groups(const struct cpumask
*cpu_map
,
7478 struct cpumask
*nodemask
)
7481 #endif /* CONFIG_NUMA */
7484 * Initialize sched groups cpu_power.
7486 * cpu_power indicates the capacity of sched group, which is used while
7487 * distributing the load between different sched groups in a sched domain.
7488 * Typically cpu_power for all the groups in a sched domain will be same unless
7489 * there are asymmetries in the topology. If there are asymmetries, group
7490 * having more cpu_power will pickup more load compared to the group having
7493 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7494 * the maximum number of tasks a group can handle in the presence of other idle
7495 * or lightly loaded groups in the same sched domain.
7497 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
7499 struct sched_domain
*child
;
7500 struct sched_group
*group
;
7502 WARN_ON(!sd
|| !sd
->groups
);
7504 if (cpu
!= cpumask_first(sched_group_cpus(sd
->groups
)))
7509 sd
->groups
->__cpu_power
= 0;
7512 * For perf policy, if the groups in child domain share resources
7513 * (for example cores sharing some portions of the cache hierarchy
7514 * or SMT), then set this domain groups cpu_power such that each group
7515 * can handle only one task, when there are other idle groups in the
7516 * same sched domain.
7518 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
7520 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
7521 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
7526 * add cpu_power of each child group to this groups cpu_power
7528 group
= child
->groups
;
7530 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
7531 group
= group
->next
;
7532 } while (group
!= child
->groups
);
7536 * Initializers for schedule domains
7537 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7540 #ifdef CONFIG_SCHED_DEBUG
7541 # define SD_INIT_NAME(sd, type) sd->name = #type
7543 # define SD_INIT_NAME(sd, type) do { } while (0)
7546 #define SD_INIT(sd, type) sd_init_##type(sd)
7548 #define SD_INIT_FUNC(type) \
7549 static noinline void sd_init_##type(struct sched_domain *sd) \
7551 memset(sd, 0, sizeof(*sd)); \
7552 *sd = SD_##type##_INIT; \
7553 sd->level = SD_LV_##type; \
7554 SD_INIT_NAME(sd, type); \
7559 SD_INIT_FUNC(ALLNODES
)
7562 #ifdef CONFIG_SCHED_SMT
7563 SD_INIT_FUNC(SIBLING
)
7565 #ifdef CONFIG_SCHED_MC
7569 static int default_relax_domain_level
= -1;
7571 static int __init
setup_relax_domain_level(char *str
)
7575 val
= simple_strtoul(str
, NULL
, 0);
7576 if (val
< SD_LV_MAX
)
7577 default_relax_domain_level
= val
;
7581 __setup("relax_domain_level=", setup_relax_domain_level
);
7583 static void set_domain_attribute(struct sched_domain
*sd
,
7584 struct sched_domain_attr
*attr
)
7588 if (!attr
|| attr
->relax_domain_level
< 0) {
7589 if (default_relax_domain_level
< 0)
7592 request
= default_relax_domain_level
;
7594 request
= attr
->relax_domain_level
;
7595 if (request
< sd
->level
) {
7596 /* turn off idle balance on this domain */
7597 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
7599 /* turn on idle balance on this domain */
7600 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
7605 * Build sched domains for a given set of cpus and attach the sched domains
7606 * to the individual cpus
7608 static int __build_sched_domains(const struct cpumask
*cpu_map
,
7609 struct sched_domain_attr
*attr
)
7611 int i
, err
= -ENOMEM
;
7612 struct root_domain
*rd
;
7613 cpumask_var_t nodemask
, this_sibling_map
, this_core_map
, send_covered
,
7616 cpumask_var_t domainspan
, covered
, notcovered
;
7617 struct sched_group
**sched_group_nodes
= NULL
;
7618 int sd_allnodes
= 0;
7620 if (!alloc_cpumask_var(&domainspan
, GFP_KERNEL
))
7622 if (!alloc_cpumask_var(&covered
, GFP_KERNEL
))
7623 goto free_domainspan
;
7624 if (!alloc_cpumask_var(¬covered
, GFP_KERNEL
))
7628 if (!alloc_cpumask_var(&nodemask
, GFP_KERNEL
))
7629 goto free_notcovered
;
7630 if (!alloc_cpumask_var(&this_sibling_map
, GFP_KERNEL
))
7632 if (!alloc_cpumask_var(&this_core_map
, GFP_KERNEL
))
7633 goto free_this_sibling_map
;
7634 if (!alloc_cpumask_var(&send_covered
, GFP_KERNEL
))
7635 goto free_this_core_map
;
7636 if (!alloc_cpumask_var(&tmpmask
, GFP_KERNEL
))
7637 goto free_send_covered
;
7641 * Allocate the per-node list of sched groups
7643 sched_group_nodes
= kcalloc(nr_node_ids
, sizeof(struct sched_group
*),
7645 if (!sched_group_nodes
) {
7646 printk(KERN_WARNING
"Can not alloc sched group node list\n");
7651 rd
= alloc_rootdomain();
7653 printk(KERN_WARNING
"Cannot alloc root domain\n");
7654 goto free_sched_groups
;
7658 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = sched_group_nodes
;
7662 * Set up domains for cpus specified by the cpu_map.
7664 for_each_cpu(i
, cpu_map
) {
7665 struct sched_domain
*sd
= NULL
, *p
;
7667 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(i
)), cpu_map
);
7670 if (cpumask_weight(cpu_map
) >
7671 SD_NODES_PER_DOMAIN
*cpumask_weight(nodemask
)) {
7672 sd
= &per_cpu(allnodes_domains
, i
).sd
;
7673 SD_INIT(sd
, ALLNODES
);
7674 set_domain_attribute(sd
, attr
);
7675 cpumask_copy(sched_domain_span(sd
), cpu_map
);
7676 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7682 sd
= &per_cpu(node_domains
, i
).sd
;
7684 set_domain_attribute(sd
, attr
);
7685 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
7689 cpumask_and(sched_domain_span(sd
),
7690 sched_domain_span(sd
), cpu_map
);
7694 sd
= &per_cpu(phys_domains
, i
).sd
;
7696 set_domain_attribute(sd
, attr
);
7697 cpumask_copy(sched_domain_span(sd
), nodemask
);
7701 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7703 #ifdef CONFIG_SCHED_MC
7705 sd
= &per_cpu(core_domains
, i
).sd
;
7707 set_domain_attribute(sd
, attr
);
7708 cpumask_and(sched_domain_span(sd
), cpu_map
,
7709 cpu_coregroup_mask(i
));
7712 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7715 #ifdef CONFIG_SCHED_SMT
7717 sd
= &per_cpu(cpu_domains
, i
).sd
;
7718 SD_INIT(sd
, SIBLING
);
7719 set_domain_attribute(sd
, attr
);
7720 cpumask_and(sched_domain_span(sd
),
7721 &per_cpu(cpu_sibling_map
, i
), cpu_map
);
7724 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7728 #ifdef CONFIG_SCHED_SMT
7729 /* Set up CPU (sibling) groups */
7730 for_each_cpu(i
, cpu_map
) {
7731 cpumask_and(this_sibling_map
,
7732 &per_cpu(cpu_sibling_map
, i
), cpu_map
);
7733 if (i
!= cpumask_first(this_sibling_map
))
7736 init_sched_build_groups(this_sibling_map
, cpu_map
,
7738 send_covered
, tmpmask
);
7742 #ifdef CONFIG_SCHED_MC
7743 /* Set up multi-core groups */
7744 for_each_cpu(i
, cpu_map
) {
7745 cpumask_and(this_core_map
, cpu_coregroup_mask(i
), cpu_map
);
7746 if (i
!= cpumask_first(this_core_map
))
7749 init_sched_build_groups(this_core_map
, cpu_map
,
7751 send_covered
, tmpmask
);
7755 /* Set up physical groups */
7756 for (i
= 0; i
< nr_node_ids
; i
++) {
7757 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
7758 if (cpumask_empty(nodemask
))
7761 init_sched_build_groups(nodemask
, cpu_map
,
7763 send_covered
, tmpmask
);
7767 /* Set up node groups */
7769 init_sched_build_groups(cpu_map
, cpu_map
,
7770 &cpu_to_allnodes_group
,
7771 send_covered
, tmpmask
);
7774 for (i
= 0; i
< nr_node_ids
; i
++) {
7775 /* Set up node groups */
7776 struct sched_group
*sg
, *prev
;
7779 cpumask_clear(covered
);
7780 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
7781 if (cpumask_empty(nodemask
)) {
7782 sched_group_nodes
[i
] = NULL
;
7786 sched_domain_node_span(i
, domainspan
);
7787 cpumask_and(domainspan
, domainspan
, cpu_map
);
7789 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
7792 printk(KERN_WARNING
"Can not alloc domain group for "
7796 sched_group_nodes
[i
] = sg
;
7797 for_each_cpu(j
, nodemask
) {
7798 struct sched_domain
*sd
;
7800 sd
= &per_cpu(node_domains
, j
).sd
;
7803 sg
->__cpu_power
= 0;
7804 cpumask_copy(sched_group_cpus(sg
), nodemask
);
7806 cpumask_or(covered
, covered
, nodemask
);
7809 for (j
= 0; j
< nr_node_ids
; j
++) {
7810 int n
= (i
+ j
) % nr_node_ids
;
7812 cpumask_complement(notcovered
, covered
);
7813 cpumask_and(tmpmask
, notcovered
, cpu_map
);
7814 cpumask_and(tmpmask
, tmpmask
, domainspan
);
7815 if (cpumask_empty(tmpmask
))
7818 cpumask_and(tmpmask
, tmpmask
, cpumask_of_node(n
));
7819 if (cpumask_empty(tmpmask
))
7822 sg
= kmalloc_node(sizeof(struct sched_group
) +
7827 "Can not alloc domain group for node %d\n", j
);
7830 sg
->__cpu_power
= 0;
7831 cpumask_copy(sched_group_cpus(sg
), tmpmask
);
7832 sg
->next
= prev
->next
;
7833 cpumask_or(covered
, covered
, tmpmask
);
7840 /* Calculate CPU power for physical packages and nodes */
7841 #ifdef CONFIG_SCHED_SMT
7842 for_each_cpu(i
, cpu_map
) {
7843 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
).sd
;
7845 init_sched_groups_power(i
, sd
);
7848 #ifdef CONFIG_SCHED_MC
7849 for_each_cpu(i
, cpu_map
) {
7850 struct sched_domain
*sd
= &per_cpu(core_domains
, i
).sd
;
7852 init_sched_groups_power(i
, sd
);
7856 for_each_cpu(i
, cpu_map
) {
7857 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
).sd
;
7859 init_sched_groups_power(i
, sd
);
7863 for (i
= 0; i
< nr_node_ids
; i
++)
7864 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7867 struct sched_group
*sg
;
7869 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
7871 init_numa_sched_groups_power(sg
);
7875 /* Attach the domains */
7876 for_each_cpu(i
, cpu_map
) {
7877 struct sched_domain
*sd
;
7878 #ifdef CONFIG_SCHED_SMT
7879 sd
= &per_cpu(cpu_domains
, i
).sd
;
7880 #elif defined(CONFIG_SCHED_MC)
7881 sd
= &per_cpu(core_domains
, i
).sd
;
7883 sd
= &per_cpu(phys_domains
, i
).sd
;
7885 cpu_attach_domain(sd
, rd
, i
);
7891 free_cpumask_var(tmpmask
);
7893 free_cpumask_var(send_covered
);
7895 free_cpumask_var(this_core_map
);
7896 free_this_sibling_map
:
7897 free_cpumask_var(this_sibling_map
);
7899 free_cpumask_var(nodemask
);
7902 free_cpumask_var(notcovered
);
7904 free_cpumask_var(covered
);
7906 free_cpumask_var(domainspan
);
7913 kfree(sched_group_nodes
);
7919 free_sched_groups(cpu_map
, tmpmask
);
7920 free_rootdomain(rd
);
7925 static int build_sched_domains(const struct cpumask
*cpu_map
)
7927 return __build_sched_domains(cpu_map
, NULL
);
7930 static struct cpumask
*doms_cur
; /* current sched domains */
7931 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7932 static struct sched_domain_attr
*dattr_cur
;
7933 /* attribues of custom domains in 'doms_cur' */
7936 * Special case: If a kmalloc of a doms_cur partition (array of
7937 * cpumask) fails, then fallback to a single sched domain,
7938 * as determined by the single cpumask fallback_doms.
7940 static cpumask_var_t fallback_doms
;
7943 * arch_update_cpu_topology lets virtualized architectures update the
7944 * cpu core maps. It is supposed to return 1 if the topology changed
7945 * or 0 if it stayed the same.
7947 int __attribute__((weak
)) arch_update_cpu_topology(void)
7953 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7954 * For now this just excludes isolated cpus, but could be used to
7955 * exclude other special cases in the future.
7957 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
7961 arch_update_cpu_topology();
7963 doms_cur
= kmalloc(cpumask_size(), GFP_KERNEL
);
7965 doms_cur
= fallback_doms
;
7966 cpumask_andnot(doms_cur
, cpu_map
, cpu_isolated_map
);
7968 err
= build_sched_domains(doms_cur
);
7969 register_sched_domain_sysctl();
7974 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
7975 struct cpumask
*tmpmask
)
7977 free_sched_groups(cpu_map
, tmpmask
);
7981 * Detach sched domains from a group of cpus specified in cpu_map
7982 * These cpus will now be attached to the NULL domain
7984 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7986 /* Save because hotplug lock held. */
7987 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
7990 for_each_cpu(i
, cpu_map
)
7991 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7992 synchronize_sched();
7993 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
7996 /* handle null as "default" */
7997 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7998 struct sched_domain_attr
*new, int idx_new
)
8000 struct sched_domain_attr tmp
;
8007 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
8008 new ? (new + idx_new
) : &tmp
,
8009 sizeof(struct sched_domain_attr
));
8013 * Partition sched domains as specified by the 'ndoms_new'
8014 * cpumasks in the array doms_new[] of cpumasks. This compares
8015 * doms_new[] to the current sched domain partitioning, doms_cur[].
8016 * It destroys each deleted domain and builds each new domain.
8018 * 'doms_new' is an array of cpumask's of length 'ndoms_new'.
8019 * The masks don't intersect (don't overlap.) We should setup one
8020 * sched domain for each mask. CPUs not in any of the cpumasks will
8021 * not be load balanced. If the same cpumask appears both in the
8022 * current 'doms_cur' domains and in the new 'doms_new', we can leave
8025 * The passed in 'doms_new' should be kmalloc'd. This routine takes
8026 * ownership of it and will kfree it when done with it. If the caller
8027 * failed the kmalloc call, then it can pass in doms_new == NULL &&
8028 * ndoms_new == 1, and partition_sched_domains() will fallback to
8029 * the single partition 'fallback_doms', it also forces the domains
8032 * If doms_new == NULL it will be replaced with cpu_online_mask.
8033 * ndoms_new == 0 is a special case for destroying existing domains,
8034 * and it will not create the default domain.
8036 * Call with hotplug lock held
8038 /* FIXME: Change to struct cpumask *doms_new[] */
8039 void partition_sched_domains(int ndoms_new
, struct cpumask
*doms_new
,
8040 struct sched_domain_attr
*dattr_new
)
8045 mutex_lock(&sched_domains_mutex
);
8047 /* always unregister in case we don't destroy any domains */
8048 unregister_sched_domain_sysctl();
8050 /* Let architecture update cpu core mappings. */
8051 new_topology
= arch_update_cpu_topology();
8053 n
= doms_new
? ndoms_new
: 0;
8055 /* Destroy deleted domains */
8056 for (i
= 0; i
< ndoms_cur
; i
++) {
8057 for (j
= 0; j
< n
&& !new_topology
; j
++) {
8058 if (cpumask_equal(&doms_cur
[i
], &doms_new
[j
])
8059 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
8062 /* no match - a current sched domain not in new doms_new[] */
8063 detach_destroy_domains(doms_cur
+ i
);
8068 if (doms_new
== NULL
) {
8070 doms_new
= fallback_doms
;
8071 cpumask_andnot(&doms_new
[0], cpu_online_mask
, cpu_isolated_map
);
8072 WARN_ON_ONCE(dattr_new
);
8075 /* Build new domains */
8076 for (i
= 0; i
< ndoms_new
; i
++) {
8077 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
8078 if (cpumask_equal(&doms_new
[i
], &doms_cur
[j
])
8079 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
8082 /* no match - add a new doms_new */
8083 __build_sched_domains(doms_new
+ i
,
8084 dattr_new
? dattr_new
+ i
: NULL
);
8089 /* Remember the new sched domains */
8090 if (doms_cur
!= fallback_doms
)
8092 kfree(dattr_cur
); /* kfree(NULL) is safe */
8093 doms_cur
= doms_new
;
8094 dattr_cur
= dattr_new
;
8095 ndoms_cur
= ndoms_new
;
8097 register_sched_domain_sysctl();
8099 mutex_unlock(&sched_domains_mutex
);
8102 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
8103 static void arch_reinit_sched_domains(void)
8107 /* Destroy domains first to force the rebuild */
8108 partition_sched_domains(0, NULL
, NULL
);
8110 rebuild_sched_domains();
8114 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
8116 unsigned int level
= 0;
8118 if (sscanf(buf
, "%u", &level
) != 1)
8122 * level is always be positive so don't check for
8123 * level < POWERSAVINGS_BALANCE_NONE which is 0
8124 * What happens on 0 or 1 byte write,
8125 * need to check for count as well?
8128 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
8132 sched_smt_power_savings
= level
;
8134 sched_mc_power_savings
= level
;
8136 arch_reinit_sched_domains();
8141 #ifdef CONFIG_SCHED_MC
8142 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
8145 return sprintf(page
, "%u\n", sched_mc_power_savings
);
8147 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
8148 const char *buf
, size_t count
)
8150 return sched_power_savings_store(buf
, count
, 0);
8152 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
8153 sched_mc_power_savings_show
,
8154 sched_mc_power_savings_store
);
8157 #ifdef CONFIG_SCHED_SMT
8158 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
8161 return sprintf(page
, "%u\n", sched_smt_power_savings
);
8163 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
8164 const char *buf
, size_t count
)
8166 return sched_power_savings_store(buf
, count
, 1);
8168 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
8169 sched_smt_power_savings_show
,
8170 sched_smt_power_savings_store
);
8173 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
8177 #ifdef CONFIG_SCHED_SMT
8179 err
= sysfs_create_file(&cls
->kset
.kobj
,
8180 &attr_sched_smt_power_savings
.attr
);
8182 #ifdef CONFIG_SCHED_MC
8183 if (!err
&& mc_capable())
8184 err
= sysfs_create_file(&cls
->kset
.kobj
,
8185 &attr_sched_mc_power_savings
.attr
);
8189 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
8191 #ifndef CONFIG_CPUSETS
8193 * Add online and remove offline CPUs from the scheduler domains.
8194 * When cpusets are enabled they take over this function.
8196 static int update_sched_domains(struct notifier_block
*nfb
,
8197 unsigned long action
, void *hcpu
)
8201 case CPU_ONLINE_FROZEN
:
8203 case CPU_DEAD_FROZEN
:
8204 partition_sched_domains(1, NULL
, NULL
);
8213 static int update_runtime(struct notifier_block
*nfb
,
8214 unsigned long action
, void *hcpu
)
8216 int cpu
= (int)(long)hcpu
;
8219 case CPU_DOWN_PREPARE
:
8220 case CPU_DOWN_PREPARE_FROZEN
:
8221 disable_runtime(cpu_rq(cpu
));
8224 case CPU_DOWN_FAILED
:
8225 case CPU_DOWN_FAILED_FROZEN
:
8227 case CPU_ONLINE_FROZEN
:
8228 enable_runtime(cpu_rq(cpu
));
8236 void __init
sched_init_smp(void)
8238 cpumask_var_t non_isolated_cpus
;
8240 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
8242 #if defined(CONFIG_NUMA)
8243 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
8245 BUG_ON(sched_group_nodes_bycpu
== NULL
);
8248 mutex_lock(&sched_domains_mutex
);
8249 arch_init_sched_domains(cpu_online_mask
);
8250 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
8251 if (cpumask_empty(non_isolated_cpus
))
8252 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
8253 mutex_unlock(&sched_domains_mutex
);
8256 #ifndef CONFIG_CPUSETS
8257 /* XXX: Theoretical race here - CPU may be hotplugged now */
8258 hotcpu_notifier(update_sched_domains
, 0);
8261 /* RT runtime code needs to handle some hotplug events */
8262 hotcpu_notifier(update_runtime
, 0);
8266 /* Move init over to a non-isolated CPU */
8267 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
8269 sched_init_granularity();
8270 free_cpumask_var(non_isolated_cpus
);
8272 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
8273 init_sched_rt_class();
8276 void __init
sched_init_smp(void)
8278 sched_init_granularity();
8280 #endif /* CONFIG_SMP */
8282 int in_sched_functions(unsigned long addr
)
8284 return in_lock_functions(addr
) ||
8285 (addr
>= (unsigned long)__sched_text_start
8286 && addr
< (unsigned long)__sched_text_end
);
8289 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
8291 cfs_rq
->tasks_timeline
= RB_ROOT
;
8292 INIT_LIST_HEAD(&cfs_rq
->tasks
);
8293 #ifdef CONFIG_FAIR_GROUP_SCHED
8296 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
8299 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
8301 struct rt_prio_array
*array
;
8304 array
= &rt_rq
->active
;
8305 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
8306 INIT_LIST_HEAD(array
->queue
+ i
);
8307 __clear_bit(i
, array
->bitmap
);
8309 /* delimiter for bitsearch: */
8310 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
8312 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8313 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
8315 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
8319 rt_rq
->rt_nr_migratory
= 0;
8320 rt_rq
->overloaded
= 0;
8321 plist_head_init(&rq
->rt
.pushable_tasks
, &rq
->lock
);
8325 rt_rq
->rt_throttled
= 0;
8326 rt_rq
->rt_runtime
= 0;
8327 spin_lock_init(&rt_rq
->rt_runtime_lock
);
8329 #ifdef CONFIG_RT_GROUP_SCHED
8330 rt_rq
->rt_nr_boosted
= 0;
8335 #ifdef CONFIG_FAIR_GROUP_SCHED
8336 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
8337 struct sched_entity
*se
, int cpu
, int add
,
8338 struct sched_entity
*parent
)
8340 struct rq
*rq
= cpu_rq(cpu
);
8341 tg
->cfs_rq
[cpu
] = cfs_rq
;
8342 init_cfs_rq(cfs_rq
, rq
);
8345 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
8348 /* se could be NULL for init_task_group */
8353 se
->cfs_rq
= &rq
->cfs
;
8355 se
->cfs_rq
= parent
->my_q
;
8358 se
->load
.weight
= tg
->shares
;
8359 se
->load
.inv_weight
= 0;
8360 se
->parent
= parent
;
8364 #ifdef CONFIG_RT_GROUP_SCHED
8365 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
8366 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
8367 struct sched_rt_entity
*parent
)
8369 struct rq
*rq
= cpu_rq(cpu
);
8371 tg
->rt_rq
[cpu
] = rt_rq
;
8372 init_rt_rq(rt_rq
, rq
);
8374 rt_rq
->rt_se
= rt_se
;
8375 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8377 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
8379 tg
->rt_se
[cpu
] = rt_se
;
8384 rt_se
->rt_rq
= &rq
->rt
;
8386 rt_se
->rt_rq
= parent
->my_q
;
8388 rt_se
->my_q
= rt_rq
;
8389 rt_se
->parent
= parent
;
8390 INIT_LIST_HEAD(&rt_se
->run_list
);
8394 void __init
sched_init(void)
8397 unsigned long alloc_size
= 0, ptr
;
8399 #ifdef CONFIG_FAIR_GROUP_SCHED
8400 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8402 #ifdef CONFIG_RT_GROUP_SCHED
8403 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8405 #ifdef CONFIG_USER_SCHED
8409 * As sched_init() is called before page_alloc is setup,
8410 * we use alloc_bootmem().
8413 ptr
= (unsigned long)alloc_bootmem(alloc_size
);
8415 #ifdef CONFIG_FAIR_GROUP_SCHED
8416 init_task_group
.se
= (struct sched_entity
**)ptr
;
8417 ptr
+= nr_cpu_ids
* sizeof(void **);
8419 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8420 ptr
+= nr_cpu_ids
* sizeof(void **);
8422 #ifdef CONFIG_USER_SCHED
8423 root_task_group
.se
= (struct sched_entity
**)ptr
;
8424 ptr
+= nr_cpu_ids
* sizeof(void **);
8426 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8427 ptr
+= nr_cpu_ids
* sizeof(void **);
8428 #endif /* CONFIG_USER_SCHED */
8429 #endif /* CONFIG_FAIR_GROUP_SCHED */
8430 #ifdef CONFIG_RT_GROUP_SCHED
8431 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8432 ptr
+= nr_cpu_ids
* sizeof(void **);
8434 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8435 ptr
+= nr_cpu_ids
* sizeof(void **);
8437 #ifdef CONFIG_USER_SCHED
8438 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8439 ptr
+= nr_cpu_ids
* sizeof(void **);
8441 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8442 ptr
+= nr_cpu_ids
* sizeof(void **);
8443 #endif /* CONFIG_USER_SCHED */
8444 #endif /* CONFIG_RT_GROUP_SCHED */
8448 init_defrootdomain();
8451 init_rt_bandwidth(&def_rt_bandwidth
,
8452 global_rt_period(), global_rt_runtime());
8454 #ifdef CONFIG_RT_GROUP_SCHED
8455 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
8456 global_rt_period(), global_rt_runtime());
8457 #ifdef CONFIG_USER_SCHED
8458 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
8459 global_rt_period(), RUNTIME_INF
);
8460 #endif /* CONFIG_USER_SCHED */
8461 #endif /* CONFIG_RT_GROUP_SCHED */
8463 #ifdef CONFIG_GROUP_SCHED
8464 list_add(&init_task_group
.list
, &task_groups
);
8465 INIT_LIST_HEAD(&init_task_group
.children
);
8467 #ifdef CONFIG_USER_SCHED
8468 INIT_LIST_HEAD(&root_task_group
.children
);
8469 init_task_group
.parent
= &root_task_group
;
8470 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
8471 #endif /* CONFIG_USER_SCHED */
8472 #endif /* CONFIG_GROUP_SCHED */
8474 for_each_possible_cpu(i
) {
8478 spin_lock_init(&rq
->lock
);
8480 init_cfs_rq(&rq
->cfs
, rq
);
8481 init_rt_rq(&rq
->rt
, rq
);
8482 #ifdef CONFIG_FAIR_GROUP_SCHED
8483 init_task_group
.shares
= init_task_group_load
;
8484 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
8485 #ifdef CONFIG_CGROUP_SCHED
8487 * How much cpu bandwidth does init_task_group get?
8489 * In case of task-groups formed thr' the cgroup filesystem, it
8490 * gets 100% of the cpu resources in the system. This overall
8491 * system cpu resource is divided among the tasks of
8492 * init_task_group and its child task-groups in a fair manner,
8493 * based on each entity's (task or task-group's) weight
8494 * (se->load.weight).
8496 * In other words, if init_task_group has 10 tasks of weight
8497 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8498 * then A0's share of the cpu resource is:
8500 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8502 * We achieve this by letting init_task_group's tasks sit
8503 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8505 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
8506 #elif defined CONFIG_USER_SCHED
8507 root_task_group
.shares
= NICE_0_LOAD
;
8508 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
8510 * In case of task-groups formed thr' the user id of tasks,
8511 * init_task_group represents tasks belonging to root user.
8512 * Hence it forms a sibling of all subsequent groups formed.
8513 * In this case, init_task_group gets only a fraction of overall
8514 * system cpu resource, based on the weight assigned to root
8515 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8516 * by letting tasks of init_task_group sit in a separate cfs_rq
8517 * (init_cfs_rq) and having one entity represent this group of
8518 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8520 init_tg_cfs_entry(&init_task_group
,
8521 &per_cpu(init_cfs_rq
, i
),
8522 &per_cpu(init_sched_entity
, i
), i
, 1,
8523 root_task_group
.se
[i
]);
8526 #endif /* CONFIG_FAIR_GROUP_SCHED */
8528 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
8529 #ifdef CONFIG_RT_GROUP_SCHED
8530 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
8531 #ifdef CONFIG_CGROUP_SCHED
8532 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
8533 #elif defined CONFIG_USER_SCHED
8534 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
8535 init_tg_rt_entry(&init_task_group
,
8536 &per_cpu(init_rt_rq
, i
),
8537 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
8538 root_task_group
.rt_se
[i
]);
8542 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
8543 rq
->cpu_load
[j
] = 0;
8547 rq
->active_balance
= 0;
8548 rq
->next_balance
= jiffies
;
8552 rq
->migration_thread
= NULL
;
8553 INIT_LIST_HEAD(&rq
->migration_queue
);
8554 rq_attach_root(rq
, &def_root_domain
);
8557 atomic_set(&rq
->nr_iowait
, 0);
8560 set_load_weight(&init_task
);
8562 #ifdef CONFIG_PREEMPT_NOTIFIERS
8563 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
8567 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
8570 #ifdef CONFIG_RT_MUTEXES
8571 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
8575 * The boot idle thread does lazy MMU switching as well:
8577 atomic_inc(&init_mm
.mm_count
);
8578 enter_lazy_tlb(&init_mm
, current
);
8581 * Make us the idle thread. Technically, schedule() should not be
8582 * called from this thread, however somewhere below it might be,
8583 * but because we are the idle thread, we just pick up running again
8584 * when this runqueue becomes "idle".
8586 init_idle(current
, smp_processor_id());
8588 * During early bootup we pretend to be a normal task:
8590 current
->sched_class
= &fair_sched_class
;
8592 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
8593 alloc_bootmem_cpumask_var(&nohz_cpu_mask
);
8596 alloc_bootmem_cpumask_var(&nohz
.cpu_mask
);
8598 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
8601 scheduler_running
= 1;
8604 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
8605 void __might_sleep(char *file
, int line
)
8608 static unsigned long prev_jiffy
; /* ratelimiting */
8610 if ((!in_atomic() && !irqs_disabled()) ||
8611 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
8613 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
8615 prev_jiffy
= jiffies
;
8618 "BUG: sleeping function called from invalid context at %s:%d\n",
8621 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
8622 in_atomic(), irqs_disabled(),
8623 current
->pid
, current
->comm
);
8625 debug_show_held_locks(current
);
8626 if (irqs_disabled())
8627 print_irqtrace_events(current
);
8631 EXPORT_SYMBOL(__might_sleep
);
8634 #ifdef CONFIG_MAGIC_SYSRQ
8635 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
8639 update_rq_clock(rq
);
8640 on_rq
= p
->se
.on_rq
;
8642 deactivate_task(rq
, p
, 0);
8643 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
8645 activate_task(rq
, p
, 0);
8646 resched_task(rq
->curr
);
8650 void normalize_rt_tasks(void)
8652 struct task_struct
*g
, *p
;
8653 unsigned long flags
;
8656 read_lock_irqsave(&tasklist_lock
, flags
);
8657 do_each_thread(g
, p
) {
8659 * Only normalize user tasks:
8664 p
->se
.exec_start
= 0;
8665 #ifdef CONFIG_SCHEDSTATS
8666 p
->se
.wait_start
= 0;
8667 p
->se
.sleep_start
= 0;
8668 p
->se
.block_start
= 0;
8673 * Renice negative nice level userspace
8676 if (TASK_NICE(p
) < 0 && p
->mm
)
8677 set_user_nice(p
, 0);
8681 spin_lock(&p
->pi_lock
);
8682 rq
= __task_rq_lock(p
);
8684 normalize_task(rq
, p
);
8686 __task_rq_unlock(rq
);
8687 spin_unlock(&p
->pi_lock
);
8688 } while_each_thread(g
, p
);
8690 read_unlock_irqrestore(&tasklist_lock
, flags
);
8693 #endif /* CONFIG_MAGIC_SYSRQ */
8697 * These functions are only useful for the IA64 MCA handling.
8699 * They can only be called when the whole system has been
8700 * stopped - every CPU needs to be quiescent, and no scheduling
8701 * activity can take place. Using them for anything else would
8702 * be a serious bug, and as a result, they aren't even visible
8703 * under any other configuration.
8707 * curr_task - return the current task for a given cpu.
8708 * @cpu: the processor in question.
8710 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8712 struct task_struct
*curr_task(int cpu
)
8714 return cpu_curr(cpu
);
8718 * set_curr_task - set the current task for a given cpu.
8719 * @cpu: the processor in question.
8720 * @p: the task pointer to set.
8722 * Description: This function must only be used when non-maskable interrupts
8723 * are serviced on a separate stack. It allows the architecture to switch the
8724 * notion of the current task on a cpu in a non-blocking manner. This function
8725 * must be called with all CPU's synchronized, and interrupts disabled, the
8726 * and caller must save the original value of the current task (see
8727 * curr_task() above) and restore that value before reenabling interrupts and
8728 * re-starting the system.
8730 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8732 void set_curr_task(int cpu
, struct task_struct
*p
)
8739 #ifdef CONFIG_FAIR_GROUP_SCHED
8740 static void free_fair_sched_group(struct task_group
*tg
)
8744 for_each_possible_cpu(i
) {
8746 kfree(tg
->cfs_rq
[i
]);
8756 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8758 struct cfs_rq
*cfs_rq
;
8759 struct sched_entity
*se
;
8763 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8766 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8770 tg
->shares
= NICE_0_LOAD
;
8772 for_each_possible_cpu(i
) {
8775 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
8776 GFP_KERNEL
, cpu_to_node(i
));
8780 se
= kzalloc_node(sizeof(struct sched_entity
),
8781 GFP_KERNEL
, cpu_to_node(i
));
8785 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
8794 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8796 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
8797 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
8800 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8802 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
8804 #else /* !CONFG_FAIR_GROUP_SCHED */
8805 static inline void free_fair_sched_group(struct task_group
*tg
)
8810 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8815 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8819 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8822 #endif /* CONFIG_FAIR_GROUP_SCHED */
8824 #ifdef CONFIG_RT_GROUP_SCHED
8825 static void free_rt_sched_group(struct task_group
*tg
)
8829 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8831 for_each_possible_cpu(i
) {
8833 kfree(tg
->rt_rq
[i
]);
8835 kfree(tg
->rt_se
[i
]);
8843 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8845 struct rt_rq
*rt_rq
;
8846 struct sched_rt_entity
*rt_se
;
8850 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8853 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8857 init_rt_bandwidth(&tg
->rt_bandwidth
,
8858 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8860 for_each_possible_cpu(i
) {
8863 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8864 GFP_KERNEL
, cpu_to_node(i
));
8868 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8869 GFP_KERNEL
, cpu_to_node(i
));
8873 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
8882 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8884 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
8885 &cpu_rq(cpu
)->leaf_rt_rq_list
);
8888 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8890 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
8892 #else /* !CONFIG_RT_GROUP_SCHED */
8893 static inline void free_rt_sched_group(struct task_group
*tg
)
8898 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8903 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8907 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8910 #endif /* CONFIG_RT_GROUP_SCHED */
8912 #ifdef CONFIG_GROUP_SCHED
8913 static void free_sched_group(struct task_group
*tg
)
8915 free_fair_sched_group(tg
);
8916 free_rt_sched_group(tg
);
8920 /* allocate runqueue etc for a new task group */
8921 struct task_group
*sched_create_group(struct task_group
*parent
)
8923 struct task_group
*tg
;
8924 unsigned long flags
;
8927 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8929 return ERR_PTR(-ENOMEM
);
8931 if (!alloc_fair_sched_group(tg
, parent
))
8934 if (!alloc_rt_sched_group(tg
, parent
))
8937 spin_lock_irqsave(&task_group_lock
, flags
);
8938 for_each_possible_cpu(i
) {
8939 register_fair_sched_group(tg
, i
);
8940 register_rt_sched_group(tg
, i
);
8942 list_add_rcu(&tg
->list
, &task_groups
);
8944 WARN_ON(!parent
); /* root should already exist */
8946 tg
->parent
= parent
;
8947 INIT_LIST_HEAD(&tg
->children
);
8948 list_add_rcu(&tg
->siblings
, &parent
->children
);
8949 spin_unlock_irqrestore(&task_group_lock
, flags
);
8954 free_sched_group(tg
);
8955 return ERR_PTR(-ENOMEM
);
8958 /* rcu callback to free various structures associated with a task group */
8959 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8961 /* now it should be safe to free those cfs_rqs */
8962 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8965 /* Destroy runqueue etc associated with a task group */
8966 void sched_destroy_group(struct task_group
*tg
)
8968 unsigned long flags
;
8971 spin_lock_irqsave(&task_group_lock
, flags
);
8972 for_each_possible_cpu(i
) {
8973 unregister_fair_sched_group(tg
, i
);
8974 unregister_rt_sched_group(tg
, i
);
8976 list_del_rcu(&tg
->list
);
8977 list_del_rcu(&tg
->siblings
);
8978 spin_unlock_irqrestore(&task_group_lock
, flags
);
8980 /* wait for possible concurrent references to cfs_rqs complete */
8981 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8984 /* change task's runqueue when it moves between groups.
8985 * The caller of this function should have put the task in its new group
8986 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8987 * reflect its new group.
8989 void sched_move_task(struct task_struct
*tsk
)
8992 unsigned long flags
;
8995 rq
= task_rq_lock(tsk
, &flags
);
8997 update_rq_clock(rq
);
8999 running
= task_current(rq
, tsk
);
9000 on_rq
= tsk
->se
.on_rq
;
9003 dequeue_task(rq
, tsk
, 0);
9004 if (unlikely(running
))
9005 tsk
->sched_class
->put_prev_task(rq
, tsk
);
9007 set_task_rq(tsk
, task_cpu(tsk
));
9009 #ifdef CONFIG_FAIR_GROUP_SCHED
9010 if (tsk
->sched_class
->moved_group
)
9011 tsk
->sched_class
->moved_group(tsk
);
9014 if (unlikely(running
))
9015 tsk
->sched_class
->set_curr_task(rq
);
9017 enqueue_task(rq
, tsk
, 0);
9019 task_rq_unlock(rq
, &flags
);
9021 #endif /* CONFIG_GROUP_SCHED */
9023 #ifdef CONFIG_FAIR_GROUP_SCHED
9024 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9026 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9031 dequeue_entity(cfs_rq
, se
, 0);
9033 se
->load
.weight
= shares
;
9034 se
->load
.inv_weight
= 0;
9037 enqueue_entity(cfs_rq
, se
, 0);
9040 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
9042 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
9043 struct rq
*rq
= cfs_rq
->rq
;
9044 unsigned long flags
;
9046 spin_lock_irqsave(&rq
->lock
, flags
);
9047 __set_se_shares(se
, shares
);
9048 spin_unlock_irqrestore(&rq
->lock
, flags
);
9051 static DEFINE_MUTEX(shares_mutex
);
9053 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
9056 unsigned long flags
;
9059 * We can't change the weight of the root cgroup.
9064 if (shares
< MIN_SHARES
)
9065 shares
= MIN_SHARES
;
9066 else if (shares
> MAX_SHARES
)
9067 shares
= MAX_SHARES
;
9069 mutex_lock(&shares_mutex
);
9070 if (tg
->shares
== shares
)
9073 spin_lock_irqsave(&task_group_lock
, flags
);
9074 for_each_possible_cpu(i
)
9075 unregister_fair_sched_group(tg
, i
);
9076 list_del_rcu(&tg
->siblings
);
9077 spin_unlock_irqrestore(&task_group_lock
, flags
);
9079 /* wait for any ongoing reference to this group to finish */
9080 synchronize_sched();
9083 * Now we are free to modify the group's share on each cpu
9084 * w/o tripping rebalance_share or load_balance_fair.
9086 tg
->shares
= shares
;
9087 for_each_possible_cpu(i
) {
9091 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
9092 set_se_shares(tg
->se
[i
], shares
);
9096 * Enable load balance activity on this group, by inserting it back on
9097 * each cpu's rq->leaf_cfs_rq_list.
9099 spin_lock_irqsave(&task_group_lock
, flags
);
9100 for_each_possible_cpu(i
)
9101 register_fair_sched_group(tg
, i
);
9102 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
9103 spin_unlock_irqrestore(&task_group_lock
, flags
);
9105 mutex_unlock(&shares_mutex
);
9109 unsigned long sched_group_shares(struct task_group
*tg
)
9115 #ifdef CONFIG_RT_GROUP_SCHED
9117 * Ensure that the real time constraints are schedulable.
9119 static DEFINE_MUTEX(rt_constraints_mutex
);
9121 static unsigned long to_ratio(u64 period
, u64 runtime
)
9123 if (runtime
== RUNTIME_INF
)
9126 return div64_u64(runtime
<< 20, period
);
9129 /* Must be called with tasklist_lock held */
9130 static inline int tg_has_rt_tasks(struct task_group
*tg
)
9132 struct task_struct
*g
, *p
;
9134 do_each_thread(g
, p
) {
9135 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
9137 } while_each_thread(g
, p
);
9142 struct rt_schedulable_data
{
9143 struct task_group
*tg
;
9148 static int tg_schedulable(struct task_group
*tg
, void *data
)
9150 struct rt_schedulable_data
*d
= data
;
9151 struct task_group
*child
;
9152 unsigned long total
, sum
= 0;
9153 u64 period
, runtime
;
9155 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9156 runtime
= tg
->rt_bandwidth
.rt_runtime
;
9159 period
= d
->rt_period
;
9160 runtime
= d
->rt_runtime
;
9163 #ifdef CONFIG_USER_SCHED
9164 if (tg
== &root_task_group
) {
9165 period
= global_rt_period();
9166 runtime
= global_rt_runtime();
9171 * Cannot have more runtime than the period.
9173 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9177 * Ensure we don't starve existing RT tasks.
9179 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
9182 total
= to_ratio(period
, runtime
);
9185 * Nobody can have more than the global setting allows.
9187 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
9191 * The sum of our children's runtime should not exceed our own.
9193 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
9194 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
9195 runtime
= child
->rt_bandwidth
.rt_runtime
;
9197 if (child
== d
->tg
) {
9198 period
= d
->rt_period
;
9199 runtime
= d
->rt_runtime
;
9202 sum
+= to_ratio(period
, runtime
);
9211 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
9213 struct rt_schedulable_data data
= {
9215 .rt_period
= period
,
9216 .rt_runtime
= runtime
,
9219 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
9222 static int tg_set_bandwidth(struct task_group
*tg
,
9223 u64 rt_period
, u64 rt_runtime
)
9227 mutex_lock(&rt_constraints_mutex
);
9228 read_lock(&tasklist_lock
);
9229 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
9233 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
9234 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
9235 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
9237 for_each_possible_cpu(i
) {
9238 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
9240 spin_lock(&rt_rq
->rt_runtime_lock
);
9241 rt_rq
->rt_runtime
= rt_runtime
;
9242 spin_unlock(&rt_rq
->rt_runtime_lock
);
9244 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
9246 read_unlock(&tasklist_lock
);
9247 mutex_unlock(&rt_constraints_mutex
);
9252 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
9254 u64 rt_runtime
, rt_period
;
9256 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9257 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
9258 if (rt_runtime_us
< 0)
9259 rt_runtime
= RUNTIME_INF
;
9261 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
9264 long sched_group_rt_runtime(struct task_group
*tg
)
9268 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
9271 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
9272 do_div(rt_runtime_us
, NSEC_PER_USEC
);
9273 return rt_runtime_us
;
9276 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
9278 u64 rt_runtime
, rt_period
;
9280 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
9281 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
9286 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
9289 long sched_group_rt_period(struct task_group
*tg
)
9293 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
9294 do_div(rt_period_us
, NSEC_PER_USEC
);
9295 return rt_period_us
;
9298 static int sched_rt_global_constraints(void)
9300 u64 runtime
, period
;
9303 if (sysctl_sched_rt_period
<= 0)
9306 runtime
= global_rt_runtime();
9307 period
= global_rt_period();
9310 * Sanity check on the sysctl variables.
9312 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
9315 mutex_lock(&rt_constraints_mutex
);
9316 read_lock(&tasklist_lock
);
9317 ret
= __rt_schedulable(NULL
, 0, 0);
9318 read_unlock(&tasklist_lock
);
9319 mutex_unlock(&rt_constraints_mutex
);
9323 #else /* !CONFIG_RT_GROUP_SCHED */
9324 static int sched_rt_global_constraints(void)
9326 unsigned long flags
;
9329 if (sysctl_sched_rt_period
<= 0)
9332 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9333 for_each_possible_cpu(i
) {
9334 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
9336 spin_lock(&rt_rq
->rt_runtime_lock
);
9337 rt_rq
->rt_runtime
= global_rt_runtime();
9338 spin_unlock(&rt_rq
->rt_runtime_lock
);
9340 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9344 #endif /* CONFIG_RT_GROUP_SCHED */
9346 int sched_rt_handler(struct ctl_table
*table
, int write
,
9347 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
9351 int old_period
, old_runtime
;
9352 static DEFINE_MUTEX(mutex
);
9355 old_period
= sysctl_sched_rt_period
;
9356 old_runtime
= sysctl_sched_rt_runtime
;
9358 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
9360 if (!ret
&& write
) {
9361 ret
= sched_rt_global_constraints();
9363 sysctl_sched_rt_period
= old_period
;
9364 sysctl_sched_rt_runtime
= old_runtime
;
9366 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
9367 def_rt_bandwidth
.rt_period
=
9368 ns_to_ktime(global_rt_period());
9371 mutex_unlock(&mutex
);
9376 #ifdef CONFIG_CGROUP_SCHED
9378 /* return corresponding task_group object of a cgroup */
9379 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
9381 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
9382 struct task_group
, css
);
9385 static struct cgroup_subsys_state
*
9386 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9388 struct task_group
*tg
, *parent
;
9390 if (!cgrp
->parent
) {
9391 /* This is early initialization for the top cgroup */
9392 return &init_task_group
.css
;
9395 parent
= cgroup_tg(cgrp
->parent
);
9396 tg
= sched_create_group(parent
);
9398 return ERR_PTR(-ENOMEM
);
9404 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9406 struct task_group
*tg
= cgroup_tg(cgrp
);
9408 sched_destroy_group(tg
);
9412 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9413 struct task_struct
*tsk
)
9415 #ifdef CONFIG_RT_GROUP_SCHED
9416 /* Don't accept realtime tasks when there is no way for them to run */
9417 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
9420 /* We don't support RT-tasks being in separate groups */
9421 if (tsk
->sched_class
!= &fair_sched_class
)
9429 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9430 struct cgroup
*old_cont
, struct task_struct
*tsk
)
9432 sched_move_task(tsk
);
9435 #ifdef CONFIG_FAIR_GROUP_SCHED
9436 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9439 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
9442 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
9444 struct task_group
*tg
= cgroup_tg(cgrp
);
9446 return (u64
) tg
->shares
;
9448 #endif /* CONFIG_FAIR_GROUP_SCHED */
9450 #ifdef CONFIG_RT_GROUP_SCHED
9451 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
9454 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
9457 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9459 return sched_group_rt_runtime(cgroup_tg(cgrp
));
9462 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
9465 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
9468 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
9470 return sched_group_rt_period(cgroup_tg(cgrp
));
9472 #endif /* CONFIG_RT_GROUP_SCHED */
9474 static struct cftype cpu_files
[] = {
9475 #ifdef CONFIG_FAIR_GROUP_SCHED
9478 .read_u64
= cpu_shares_read_u64
,
9479 .write_u64
= cpu_shares_write_u64
,
9482 #ifdef CONFIG_RT_GROUP_SCHED
9484 .name
= "rt_runtime_us",
9485 .read_s64
= cpu_rt_runtime_read
,
9486 .write_s64
= cpu_rt_runtime_write
,
9489 .name
= "rt_period_us",
9490 .read_u64
= cpu_rt_period_read_uint
,
9491 .write_u64
= cpu_rt_period_write_uint
,
9496 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
9498 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
9501 struct cgroup_subsys cpu_cgroup_subsys
= {
9503 .create
= cpu_cgroup_create
,
9504 .destroy
= cpu_cgroup_destroy
,
9505 .can_attach
= cpu_cgroup_can_attach
,
9506 .attach
= cpu_cgroup_attach
,
9507 .populate
= cpu_cgroup_populate
,
9508 .subsys_id
= cpu_cgroup_subsys_id
,
9512 #endif /* CONFIG_CGROUP_SCHED */
9514 #ifdef CONFIG_CGROUP_CPUACCT
9517 * CPU accounting code for task groups.
9519 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9520 * (balbir@in.ibm.com).
9523 /* track cpu usage of a group of tasks and its child groups */
9525 struct cgroup_subsys_state css
;
9526 /* cpuusage holds pointer to a u64-type object on every cpu */
9528 struct cpuacct
*parent
;
9531 struct cgroup_subsys cpuacct_subsys
;
9533 /* return cpu accounting group corresponding to this container */
9534 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
9536 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
9537 struct cpuacct
, css
);
9540 /* return cpu accounting group to which this task belongs */
9541 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
9543 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
9544 struct cpuacct
, css
);
9547 /* create a new cpu accounting group */
9548 static struct cgroup_subsys_state
*cpuacct_create(
9549 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9551 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
9554 return ERR_PTR(-ENOMEM
);
9556 ca
->cpuusage
= alloc_percpu(u64
);
9557 if (!ca
->cpuusage
) {
9559 return ERR_PTR(-ENOMEM
);
9563 ca
->parent
= cgroup_ca(cgrp
->parent
);
9568 /* destroy an existing cpu accounting group */
9570 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9572 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9574 free_percpu(ca
->cpuusage
);
9578 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
9580 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, cpu
);
9583 #ifndef CONFIG_64BIT
9585 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
9587 spin_lock_irq(&cpu_rq(cpu
)->lock
);
9589 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9597 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
9599 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, cpu
);
9601 #ifndef CONFIG_64BIT
9603 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
9605 spin_lock_irq(&cpu_rq(cpu
)->lock
);
9607 spin_unlock_irq(&cpu_rq(cpu
)->lock
);
9613 /* return total cpu usage (in nanoseconds) of a group */
9614 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9616 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9617 u64 totalcpuusage
= 0;
9620 for_each_present_cpu(i
)
9621 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
9623 return totalcpuusage
;
9626 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
9629 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9638 for_each_present_cpu(i
)
9639 cpuacct_cpuusage_write(ca
, i
, 0);
9645 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
9648 struct cpuacct
*ca
= cgroup_ca(cgroup
);
9652 for_each_present_cpu(i
) {
9653 percpu
= cpuacct_cpuusage_read(ca
, i
);
9654 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
9656 seq_printf(m
, "\n");
9660 static struct cftype files
[] = {
9663 .read_u64
= cpuusage_read
,
9664 .write_u64
= cpuusage_write
,
9667 .name
= "usage_percpu",
9668 .read_seq_string
= cpuacct_percpu_seq_read
,
9673 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9675 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
9679 * charge this task's execution time to its accounting group.
9681 * called with rq->lock held.
9683 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
9688 if (!cpuacct_subsys
.active
)
9691 cpu
= task_cpu(tsk
);
9694 for (; ca
; ca
= ca
->parent
) {
9695 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, cpu
);
9696 *cpuusage
+= cputime
;
9700 struct cgroup_subsys cpuacct_subsys
= {
9702 .create
= cpuacct_create
,
9703 .destroy
= cpuacct_destroy
,
9704 .populate
= cpuacct_populate
,
9705 .subsys_id
= cpuacct_subsys_id
,
9707 #endif /* CONFIG_CGROUP_CPUACCT */