4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/perf_event.h>
43 #include <linux/security.h>
44 #include <linux/notifier.h>
45 #include <linux/profile.h>
46 #include <linux/freezer.h>
47 #include <linux/vmalloc.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/pid_namespace.h>
51 #include <linux/smp.h>
52 #include <linux/threads.h>
53 #include <linux/timer.h>
54 #include <linux/rcupdate.h>
55 #include <linux/cpu.h>
56 #include <linux/cpuset.h>
57 #include <linux/percpu.h>
58 #include <linux/kthread.h>
59 #include <linux/proc_fs.h>
60 #include <linux/seq_file.h>
61 #include <linux/sysctl.h>
62 #include <linux/syscalls.h>
63 #include <linux/times.h>
64 #include <linux/tsacct_kern.h>
65 #include <linux/kprobes.h>
66 #include <linux/delayacct.h>
67 #include <linux/unistd.h>
68 #include <linux/pagemap.h>
69 #include <linux/hrtimer.h>
70 #include <linux/tick.h>
71 #include <linux/debugfs.h>
72 #include <linux/ctype.h>
73 #include <linux/ftrace.h>
76 #include <asm/irq_regs.h>
78 #include "sched_cpupri.h"
80 #define CREATE_TRACE_POINTS
81 #include <trace/events/sched.h>
84 * Convert user-nice values [ -20 ... 0 ... 19 ]
85 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
88 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
89 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
90 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
93 * 'User priority' is the nice value converted to something we
94 * can work with better when scaling various scheduler parameters,
95 * it's a [ 0 ... 39 ] range.
97 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
98 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
99 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
102 * Helpers for converting nanosecond timing to jiffy resolution
104 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
106 #define NICE_0_LOAD SCHED_LOAD_SCALE
107 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
110 * These are the 'tuning knobs' of the scheduler:
112 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
113 * Timeslices get refilled after they expire.
115 #define DEF_TIMESLICE (100 * HZ / 1000)
118 * single value that denotes runtime == period, ie unlimited time.
120 #define RUNTIME_INF ((u64)~0ULL)
122 static inline int rt_policy(int policy
)
124 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
129 static inline int task_has_rt_policy(struct task_struct
*p
)
131 return rt_policy(p
->policy
);
135 * This is the priority-queue data structure of the RT scheduling class:
137 struct rt_prio_array
{
138 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
139 struct list_head queue
[MAX_RT_PRIO
];
142 struct rt_bandwidth
{
143 /* nests inside the rq lock: */
144 raw_spinlock_t rt_runtime_lock
;
147 struct hrtimer rt_period_timer
;
150 static struct rt_bandwidth def_rt_bandwidth
;
152 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
154 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
156 struct rt_bandwidth
*rt_b
=
157 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
163 now
= hrtimer_cb_get_time(timer
);
164 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
169 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
172 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
176 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
178 rt_b
->rt_period
= ns_to_ktime(period
);
179 rt_b
->rt_runtime
= runtime
;
181 raw_spin_lock_init(&rt_b
->rt_runtime_lock
);
183 hrtimer_init(&rt_b
->rt_period_timer
,
184 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
185 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
188 static inline int rt_bandwidth_enabled(void)
190 return sysctl_sched_rt_runtime
>= 0;
193 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
197 if (!rt_bandwidth_enabled() || rt_b
->rt_runtime
== RUNTIME_INF
)
200 if (hrtimer_active(&rt_b
->rt_period_timer
))
203 raw_spin_lock(&rt_b
->rt_runtime_lock
);
208 if (hrtimer_active(&rt_b
->rt_period_timer
))
211 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
212 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
214 soft
= hrtimer_get_softexpires(&rt_b
->rt_period_timer
);
215 hard
= hrtimer_get_expires(&rt_b
->rt_period_timer
);
216 delta
= ktime_to_ns(ktime_sub(hard
, soft
));
217 __hrtimer_start_range_ns(&rt_b
->rt_period_timer
, soft
, delta
,
218 HRTIMER_MODE_ABS_PINNED
, 0);
220 raw_spin_unlock(&rt_b
->rt_runtime_lock
);
223 #ifdef CONFIG_RT_GROUP_SCHED
224 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
226 hrtimer_cancel(&rt_b
->rt_period_timer
);
231 * sched_domains_mutex serializes calls to arch_init_sched_domains,
232 * detach_destroy_domains and partition_sched_domains.
234 static DEFINE_MUTEX(sched_domains_mutex
);
236 #ifdef CONFIG_CGROUP_SCHED
238 #include <linux/cgroup.h>
242 static LIST_HEAD(task_groups
);
244 /* task group related information */
246 struct cgroup_subsys_state css
;
248 #ifdef CONFIG_FAIR_GROUP_SCHED
249 /* schedulable entities of this group on each cpu */
250 struct sched_entity
**se
;
251 /* runqueue "owned" by this group on each cpu */
252 struct cfs_rq
**cfs_rq
;
253 unsigned long shares
;
256 #ifdef CONFIG_RT_GROUP_SCHED
257 struct sched_rt_entity
**rt_se
;
258 struct rt_rq
**rt_rq
;
260 struct rt_bandwidth rt_bandwidth
;
264 struct list_head list
;
266 struct task_group
*parent
;
267 struct list_head siblings
;
268 struct list_head children
;
271 #define root_task_group init_task_group
273 /* task_group_lock serializes add/remove of task groups and also changes to
274 * a task group's cpu shares.
276 static DEFINE_SPINLOCK(task_group_lock
);
278 #ifdef CONFIG_FAIR_GROUP_SCHED
281 static int root_task_group_empty(void)
283 return list_empty(&root_task_group
.children
);
287 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
290 * A weight of 0 or 1 can cause arithmetics problems.
291 * A weight of a cfs_rq is the sum of weights of which entities
292 * are queued on this cfs_rq, so a weight of a entity should not be
293 * too large, so as the shares value of a task group.
294 * (The default weight is 1024 - so there's no practical
295 * limitation from this.)
298 #define MAX_SHARES (1UL << 18)
300 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
303 /* Default task group.
304 * Every task in system belong to this group at bootup.
306 struct task_group init_task_group
;
308 /* return group to which a task belongs */
309 static inline struct task_group
*task_group(struct task_struct
*p
)
311 struct task_group
*tg
;
313 #ifdef CONFIG_CGROUP_SCHED
314 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
315 struct task_group
, css
);
317 tg
= &init_task_group
;
322 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
323 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
325 #ifdef CONFIG_FAIR_GROUP_SCHED
326 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
327 p
->se
.parent
= task_group(p
)->se
[cpu
];
330 #ifdef CONFIG_RT_GROUP_SCHED
331 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
332 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
338 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
339 static inline struct task_group
*task_group(struct task_struct
*p
)
344 #endif /* CONFIG_CGROUP_SCHED */
346 /* CFS-related fields in a runqueue */
348 struct load_weight load
;
349 unsigned long nr_running
;
354 struct rb_root tasks_timeline
;
355 struct rb_node
*rb_leftmost
;
357 struct list_head tasks
;
358 struct list_head
*balance_iterator
;
361 * 'curr' points to currently running entity on this cfs_rq.
362 * It is set to NULL otherwise (i.e when none are currently running).
364 struct sched_entity
*curr
, *next
, *last
;
366 unsigned int nr_spread_over
;
368 #ifdef CONFIG_FAIR_GROUP_SCHED
369 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
372 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
373 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
374 * (like users, containers etc.)
376 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
377 * list is used during load balance.
379 struct list_head leaf_cfs_rq_list
;
380 struct task_group
*tg
; /* group that "owns" this runqueue */
384 * the part of load.weight contributed by tasks
386 unsigned long task_weight
;
389 * h_load = weight * f(tg)
391 * Where f(tg) is the recursive weight fraction assigned to
394 unsigned long h_load
;
397 * this cpu's part of tg->shares
399 unsigned long shares
;
402 * load.weight at the time we set shares
404 unsigned long rq_weight
;
409 /* Real-Time classes' related field in a runqueue: */
411 struct rt_prio_array active
;
412 unsigned long rt_nr_running
;
413 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
415 int curr
; /* highest queued rt task prio */
417 int next
; /* next highest */
422 unsigned long rt_nr_migratory
;
423 unsigned long rt_nr_total
;
425 struct plist_head pushable_tasks
;
430 /* Nests inside the rq lock: */
431 raw_spinlock_t rt_runtime_lock
;
433 #ifdef CONFIG_RT_GROUP_SCHED
434 unsigned long rt_nr_boosted
;
437 struct list_head leaf_rt_rq_list
;
438 struct task_group
*tg
;
445 * We add the notion of a root-domain which will be used to define per-domain
446 * variables. Each exclusive cpuset essentially defines an island domain by
447 * fully partitioning the member cpus from any other cpuset. Whenever a new
448 * exclusive cpuset is created, we also create and attach a new root-domain
455 cpumask_var_t online
;
458 * The "RT overload" flag: it gets set if a CPU has more than
459 * one runnable RT task.
461 cpumask_var_t rto_mask
;
464 struct cpupri cpupri
;
469 * By default the system creates a single root-domain with all cpus as
470 * members (mimicking the global state we have today).
472 static struct root_domain def_root_domain
;
477 * This is the main, per-CPU runqueue data structure.
479 * Locking rule: those places that want to lock multiple runqueues
480 * (such as the load balancing or the thread migration code), lock
481 * acquire operations must be ordered by ascending &runqueue.
488 * nr_running and cpu_load should be in the same cacheline because
489 * remote CPUs use both these fields when doing load calculation.
491 unsigned long nr_running
;
492 #define CPU_LOAD_IDX_MAX 5
493 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
495 unsigned char in_nohz_recently
;
497 /* capture load from *all* tasks on this cpu: */
498 struct load_weight load
;
499 unsigned long nr_load_updates
;
505 #ifdef CONFIG_FAIR_GROUP_SCHED
506 /* list of leaf cfs_rq on this cpu: */
507 struct list_head leaf_cfs_rq_list
;
509 #ifdef CONFIG_RT_GROUP_SCHED
510 struct list_head leaf_rt_rq_list
;
514 * This is part of a global counter where only the total sum
515 * over all CPUs matters. A task can increase this counter on
516 * one CPU and if it got migrated afterwards it may decrease
517 * it on another CPU. Always updated under the runqueue lock:
519 unsigned long nr_uninterruptible
;
521 struct task_struct
*curr
, *idle
;
522 unsigned long next_balance
;
523 struct mm_struct
*prev_mm
;
530 struct root_domain
*rd
;
531 struct sched_domain
*sd
;
533 unsigned char idle_at_tick
;
534 /* For active balancing */
538 /* cpu of this runqueue: */
542 unsigned long avg_load_per_task
;
544 struct task_struct
*migration_thread
;
545 struct list_head migration_queue
;
553 /* calc_load related fields */
554 unsigned long calc_load_update
;
555 long calc_load_active
;
557 #ifdef CONFIG_SCHED_HRTICK
559 int hrtick_csd_pending
;
560 struct call_single_data hrtick_csd
;
562 struct hrtimer hrtick_timer
;
565 #ifdef CONFIG_SCHEDSTATS
567 struct sched_info rq_sched_info
;
568 unsigned long long rq_cpu_time
;
569 /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
571 /* sys_sched_yield() stats */
572 unsigned int yld_count
;
574 /* schedule() stats */
575 unsigned int sched_switch
;
576 unsigned int sched_count
;
577 unsigned int sched_goidle
;
579 /* try_to_wake_up() stats */
580 unsigned int ttwu_count
;
581 unsigned int ttwu_local
;
584 unsigned int bkl_count
;
588 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
591 void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
, int flags
)
593 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
, flags
);
596 static inline int cpu_of(struct rq
*rq
)
606 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
607 * See detach_destroy_domains: synchronize_sched for details.
609 * The domain tree of any CPU may only be accessed from within
610 * preempt-disabled sections.
612 #define for_each_domain(cpu, __sd) \
613 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
615 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
616 #define this_rq() (&__get_cpu_var(runqueues))
617 #define task_rq(p) cpu_rq(task_cpu(p))
618 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
619 #define raw_rq() (&__raw_get_cpu_var(runqueues))
621 inline void update_rq_clock(struct rq
*rq
)
623 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
627 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
629 #ifdef CONFIG_SCHED_DEBUG
630 # define const_debug __read_mostly
632 # define const_debug static const
637 * @cpu: the processor in question.
639 * Returns true if the current cpu runqueue is locked.
640 * This interface allows printk to be called with the runqueue lock
641 * held and know whether or not it is OK to wake up the klogd.
643 int runqueue_is_locked(int cpu
)
645 return raw_spin_is_locked(&cpu_rq(cpu
)->lock
);
649 * Debugging: various feature bits
652 #define SCHED_FEAT(name, enabled) \
653 __SCHED_FEAT_##name ,
656 #include "sched_features.h"
661 #define SCHED_FEAT(name, enabled) \
662 (1UL << __SCHED_FEAT_##name) * enabled |
664 const_debug
unsigned int sysctl_sched_features
=
665 #include "sched_features.h"
670 #ifdef CONFIG_SCHED_DEBUG
671 #define SCHED_FEAT(name, enabled) \
674 static __read_mostly
char *sched_feat_names
[] = {
675 #include "sched_features.h"
681 static int sched_feat_show(struct seq_file
*m
, void *v
)
685 for (i
= 0; sched_feat_names
[i
]; i
++) {
686 if (!(sysctl_sched_features
& (1UL << i
)))
688 seq_printf(m
, "%s ", sched_feat_names
[i
]);
696 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
697 size_t cnt
, loff_t
*ppos
)
707 if (copy_from_user(&buf
, ubuf
, cnt
))
712 if (strncmp(buf
, "NO_", 3) == 0) {
717 for (i
= 0; sched_feat_names
[i
]; i
++) {
718 int len
= strlen(sched_feat_names
[i
]);
720 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
722 sysctl_sched_features
&= ~(1UL << i
);
724 sysctl_sched_features
|= (1UL << i
);
729 if (!sched_feat_names
[i
])
737 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
739 return single_open(filp
, sched_feat_show
, NULL
);
742 static const struct file_operations sched_feat_fops
= {
743 .open
= sched_feat_open
,
744 .write
= sched_feat_write
,
747 .release
= single_release
,
750 static __init
int sched_init_debug(void)
752 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
757 late_initcall(sched_init_debug
);
761 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
764 * Number of tasks to iterate in a single balance run.
765 * Limited because this is done with IRQs disabled.
767 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
770 * ratelimit for updating the group shares.
773 unsigned int sysctl_sched_shares_ratelimit
= 250000;
774 unsigned int normalized_sysctl_sched_shares_ratelimit
= 250000;
777 * Inject some fuzzyness into changing the per-cpu group shares
778 * this avoids remote rq-locks at the expense of fairness.
781 unsigned int sysctl_sched_shares_thresh
= 4;
784 * period over which we average the RT time consumption, measured
789 const_debug
unsigned int sysctl_sched_time_avg
= MSEC_PER_SEC
;
792 * period over which we measure -rt task cpu usage in us.
795 unsigned int sysctl_sched_rt_period
= 1000000;
797 static __read_mostly
int scheduler_running
;
800 * part of the period that we allow rt tasks to run in us.
803 int sysctl_sched_rt_runtime
= 950000;
805 static inline u64
global_rt_period(void)
807 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
810 static inline u64
global_rt_runtime(void)
812 if (sysctl_sched_rt_runtime
< 0)
815 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
818 #ifndef prepare_arch_switch
819 # define prepare_arch_switch(next) do { } while (0)
821 #ifndef finish_arch_switch
822 # define finish_arch_switch(prev) do { } while (0)
825 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
827 return rq
->curr
== p
;
830 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
831 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
833 return task_current(rq
, p
);
836 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
840 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
842 #ifdef CONFIG_DEBUG_SPINLOCK
843 /* this is a valid case when another task releases the spinlock */
844 rq
->lock
.owner
= current
;
847 * If we are tracking spinlock dependencies then we have to
848 * fix up the runqueue lock - which gets 'carried over' from
851 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
853 raw_spin_unlock_irq(&rq
->lock
);
856 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
857 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
862 return task_current(rq
, p
);
866 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
870 * We can optimise this out completely for !SMP, because the
871 * SMP rebalancing from interrupt is the only thing that cares
876 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
877 raw_spin_unlock_irq(&rq
->lock
);
879 raw_spin_unlock(&rq
->lock
);
883 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
887 * After ->oncpu is cleared, the task can be moved to a different CPU.
888 * We must ensure this doesn't happen until the switch is completely
894 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
898 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
901 * __task_rq_lock - lock the runqueue a given task resides on.
902 * Must be called interrupts disabled.
904 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
908 struct rq
*rq
= task_rq(p
);
909 raw_spin_lock(&rq
->lock
);
910 if (likely(rq
== task_rq(p
)))
912 raw_spin_unlock(&rq
->lock
);
917 * task_rq_lock - lock the runqueue a given task resides on and disable
918 * interrupts. Note the ordering: we can safely lookup the task_rq without
919 * explicitly disabling preemption.
921 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
927 local_irq_save(*flags
);
929 raw_spin_lock(&rq
->lock
);
930 if (likely(rq
== task_rq(p
)))
932 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
936 void task_rq_unlock_wait(struct task_struct
*p
)
938 struct rq
*rq
= task_rq(p
);
940 smp_mb(); /* spin-unlock-wait is not a full memory barrier */
941 raw_spin_unlock_wait(&rq
->lock
);
944 static void __task_rq_unlock(struct rq
*rq
)
947 raw_spin_unlock(&rq
->lock
);
950 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
953 raw_spin_unlock_irqrestore(&rq
->lock
, *flags
);
957 * this_rq_lock - lock this runqueue and disable interrupts.
959 static struct rq
*this_rq_lock(void)
966 raw_spin_lock(&rq
->lock
);
971 #ifdef CONFIG_SCHED_HRTICK
973 * Use HR-timers to deliver accurate preemption points.
975 * Its all a bit involved since we cannot program an hrt while holding the
976 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
979 * When we get rescheduled we reprogram the hrtick_timer outside of the
985 * - enabled by features
986 * - hrtimer is actually high res
988 static inline int hrtick_enabled(struct rq
*rq
)
990 if (!sched_feat(HRTICK
))
992 if (!cpu_active(cpu_of(rq
)))
994 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
997 static void hrtick_clear(struct rq
*rq
)
999 if (hrtimer_active(&rq
->hrtick_timer
))
1000 hrtimer_cancel(&rq
->hrtick_timer
);
1004 * High-resolution timer tick.
1005 * Runs from hardirq context with interrupts disabled.
1007 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1009 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1011 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1013 raw_spin_lock(&rq
->lock
);
1014 update_rq_clock(rq
);
1015 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1016 raw_spin_unlock(&rq
->lock
);
1018 return HRTIMER_NORESTART
;
1023 * called from hardirq (IPI) context
1025 static void __hrtick_start(void *arg
)
1027 struct rq
*rq
= arg
;
1029 raw_spin_lock(&rq
->lock
);
1030 hrtimer_restart(&rq
->hrtick_timer
);
1031 rq
->hrtick_csd_pending
= 0;
1032 raw_spin_unlock(&rq
->lock
);
1036 * Called to set the hrtick timer state.
1038 * called with rq->lock held and irqs disabled
1040 static void hrtick_start(struct rq
*rq
, u64 delay
)
1042 struct hrtimer
*timer
= &rq
->hrtick_timer
;
1043 ktime_t time
= ktime_add_ns(timer
->base
->get_time(), delay
);
1045 hrtimer_set_expires(timer
, time
);
1047 if (rq
== this_rq()) {
1048 hrtimer_restart(timer
);
1049 } else if (!rq
->hrtick_csd_pending
) {
1050 __smp_call_function_single(cpu_of(rq
), &rq
->hrtick_csd
, 0);
1051 rq
->hrtick_csd_pending
= 1;
1056 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1058 int cpu
= (int)(long)hcpu
;
1061 case CPU_UP_CANCELED
:
1062 case CPU_UP_CANCELED_FROZEN
:
1063 case CPU_DOWN_PREPARE
:
1064 case CPU_DOWN_PREPARE_FROZEN
:
1066 case CPU_DEAD_FROZEN
:
1067 hrtick_clear(cpu_rq(cpu
));
1074 static __init
void init_hrtick(void)
1076 hotcpu_notifier(hotplug_hrtick
, 0);
1080 * Called to set the hrtick timer state.
1082 * called with rq->lock held and irqs disabled
1084 static void hrtick_start(struct rq
*rq
, u64 delay
)
1086 __hrtimer_start_range_ns(&rq
->hrtick_timer
, ns_to_ktime(delay
), 0,
1087 HRTIMER_MODE_REL_PINNED
, 0);
1090 static inline void init_hrtick(void)
1093 #endif /* CONFIG_SMP */
1095 static void init_rq_hrtick(struct rq
*rq
)
1098 rq
->hrtick_csd_pending
= 0;
1100 rq
->hrtick_csd
.flags
= 0;
1101 rq
->hrtick_csd
.func
= __hrtick_start
;
1102 rq
->hrtick_csd
.info
= rq
;
1105 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1106 rq
->hrtick_timer
.function
= hrtick
;
1108 #else /* CONFIG_SCHED_HRTICK */
1109 static inline void hrtick_clear(struct rq
*rq
)
1113 static inline void init_rq_hrtick(struct rq
*rq
)
1117 static inline void init_hrtick(void)
1120 #endif /* CONFIG_SCHED_HRTICK */
1123 * resched_task - mark a task 'to be rescheduled now'.
1125 * On UP this means the setting of the need_resched flag, on SMP it
1126 * might also involve a cross-CPU call to trigger the scheduler on
1131 #ifndef tsk_is_polling
1132 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1135 static void resched_task(struct task_struct
*p
)
1139 assert_raw_spin_locked(&task_rq(p
)->lock
);
1141 if (test_tsk_need_resched(p
))
1144 set_tsk_need_resched(p
);
1147 if (cpu
== smp_processor_id())
1150 /* NEED_RESCHED must be visible before we test polling */
1152 if (!tsk_is_polling(p
))
1153 smp_send_reschedule(cpu
);
1156 static void resched_cpu(int cpu
)
1158 struct rq
*rq
= cpu_rq(cpu
);
1159 unsigned long flags
;
1161 if (!raw_spin_trylock_irqsave(&rq
->lock
, flags
))
1163 resched_task(cpu_curr(cpu
));
1164 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1169 * When add_timer_on() enqueues a timer into the timer wheel of an
1170 * idle CPU then this timer might expire before the next timer event
1171 * which is scheduled to wake up that CPU. In case of a completely
1172 * idle system the next event might even be infinite time into the
1173 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1174 * leaves the inner idle loop so the newly added timer is taken into
1175 * account when the CPU goes back to idle and evaluates the timer
1176 * wheel for the next timer event.
1178 void wake_up_idle_cpu(int cpu
)
1180 struct rq
*rq
= cpu_rq(cpu
);
1182 if (cpu
== smp_processor_id())
1186 * This is safe, as this function is called with the timer
1187 * wheel base lock of (cpu) held. When the CPU is on the way
1188 * to idle and has not yet set rq->curr to idle then it will
1189 * be serialized on the timer wheel base lock and take the new
1190 * timer into account automatically.
1192 if (rq
->curr
!= rq
->idle
)
1196 * We can set TIF_RESCHED on the idle task of the other CPU
1197 * lockless. The worst case is that the other CPU runs the
1198 * idle task through an additional NOOP schedule()
1200 set_tsk_need_resched(rq
->idle
);
1202 /* NEED_RESCHED must be visible before we test polling */
1204 if (!tsk_is_polling(rq
->idle
))
1205 smp_send_reschedule(cpu
);
1207 #endif /* CONFIG_NO_HZ */
1209 static u64
sched_avg_period(void)
1211 return (u64
)sysctl_sched_time_avg
* NSEC_PER_MSEC
/ 2;
1214 static void sched_avg_update(struct rq
*rq
)
1216 s64 period
= sched_avg_period();
1218 while ((s64
)(rq
->clock
- rq
->age_stamp
) > period
) {
1219 rq
->age_stamp
+= period
;
1224 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1226 rq
->rt_avg
+= rt_delta
;
1227 sched_avg_update(rq
);
1230 #else /* !CONFIG_SMP */
1231 static void resched_task(struct task_struct
*p
)
1233 assert_raw_spin_locked(&task_rq(p
)->lock
);
1234 set_tsk_need_resched(p
);
1237 static void sched_rt_avg_update(struct rq
*rq
, u64 rt_delta
)
1240 #endif /* CONFIG_SMP */
1242 #if BITS_PER_LONG == 32
1243 # define WMULT_CONST (~0UL)
1245 # define WMULT_CONST (1UL << 32)
1248 #define WMULT_SHIFT 32
1251 * Shift right and round:
1253 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1256 * delta *= weight / lw
1258 static unsigned long
1259 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1260 struct load_weight
*lw
)
1264 if (!lw
->inv_weight
) {
1265 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1268 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1272 tmp
= (u64
)delta_exec
* weight
;
1274 * Check whether we'd overflow the 64-bit multiplication:
1276 if (unlikely(tmp
> WMULT_CONST
))
1277 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1280 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1282 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1285 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1291 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1298 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1299 * of tasks with abnormal "nice" values across CPUs the contribution that
1300 * each task makes to its run queue's load is weighted according to its
1301 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1302 * scaled version of the new time slice allocation that they receive on time
1306 #define WEIGHT_IDLEPRIO 3
1307 #define WMULT_IDLEPRIO 1431655765
1310 * Nice levels are multiplicative, with a gentle 10% change for every
1311 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1312 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1313 * that remained on nice 0.
1315 * The "10% effect" is relative and cumulative: from _any_ nice level,
1316 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1317 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1318 * If a task goes up by ~10% and another task goes down by ~10% then
1319 * the relative distance between them is ~25%.)
1321 static const int prio_to_weight
[40] = {
1322 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1323 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1324 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1325 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1326 /* 0 */ 1024, 820, 655, 526, 423,
1327 /* 5 */ 335, 272, 215, 172, 137,
1328 /* 10 */ 110, 87, 70, 56, 45,
1329 /* 15 */ 36, 29, 23, 18, 15,
1333 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1335 * In cases where the weight does not change often, we can use the
1336 * precalculated inverse to speed up arithmetics by turning divisions
1337 * into multiplications:
1339 static const u32 prio_to_wmult
[40] = {
1340 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1341 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1342 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1343 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1344 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1345 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1346 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1347 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1350 /* Time spent by the tasks of the cpu accounting group executing in ... */
1351 enum cpuacct_stat_index
{
1352 CPUACCT_STAT_USER
, /* ... user mode */
1353 CPUACCT_STAT_SYSTEM
, /* ... kernel mode */
1355 CPUACCT_STAT_NSTATS
,
1358 #ifdef CONFIG_CGROUP_CPUACCT
1359 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1360 static void cpuacct_update_stats(struct task_struct
*tsk
,
1361 enum cpuacct_stat_index idx
, cputime_t val
);
1363 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1364 static inline void cpuacct_update_stats(struct task_struct
*tsk
,
1365 enum cpuacct_stat_index idx
, cputime_t val
) {}
1368 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1370 update_load_add(&rq
->load
, load
);
1373 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1375 update_load_sub(&rq
->load
, load
);
1378 #if (defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)) || defined(CONFIG_RT_GROUP_SCHED)
1379 typedef int (*tg_visitor
)(struct task_group
*, void *);
1382 * Iterate the full tree, calling @down when first entering a node and @up when
1383 * leaving it for the final time.
1385 static int walk_tg_tree(tg_visitor down
, tg_visitor up
, void *data
)
1387 struct task_group
*parent
, *child
;
1391 parent
= &root_task_group
;
1393 ret
= (*down
)(parent
, data
);
1396 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1403 ret
= (*up
)(parent
, data
);
1408 parent
= parent
->parent
;
1417 static int tg_nop(struct task_group
*tg
, void *data
)
1424 /* Used instead of source_load when we know the type == 0 */
1425 static unsigned long weighted_cpuload(const int cpu
)
1427 return cpu_rq(cpu
)->load
.weight
;
1431 * Return a low guess at the load of a migration-source cpu weighted
1432 * according to the scheduling class and "nice" value.
1434 * We want to under-estimate the load of migration sources, to
1435 * balance conservatively.
1437 static unsigned long source_load(int cpu
, int type
)
1439 struct rq
*rq
= cpu_rq(cpu
);
1440 unsigned long total
= weighted_cpuload(cpu
);
1442 if (type
== 0 || !sched_feat(LB_BIAS
))
1445 return min(rq
->cpu_load
[type
-1], total
);
1449 * Return a high guess at the load of a migration-target cpu weighted
1450 * according to the scheduling class and "nice" value.
1452 static unsigned long target_load(int cpu
, int type
)
1454 struct rq
*rq
= cpu_rq(cpu
);
1455 unsigned long total
= weighted_cpuload(cpu
);
1457 if (type
== 0 || !sched_feat(LB_BIAS
))
1460 return max(rq
->cpu_load
[type
-1], total
);
1463 static struct sched_group
*group_of(int cpu
)
1465 struct sched_domain
*sd
= rcu_dereference(cpu_rq(cpu
)->sd
);
1473 static unsigned long power_of(int cpu
)
1475 struct sched_group
*group
= group_of(cpu
);
1478 return SCHED_LOAD_SCALE
;
1480 return group
->cpu_power
;
1483 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1485 static unsigned long cpu_avg_load_per_task(int cpu
)
1487 struct rq
*rq
= cpu_rq(cpu
);
1488 unsigned long nr_running
= ACCESS_ONCE(rq
->nr_running
);
1491 rq
->avg_load_per_task
= rq
->load
.weight
/ nr_running
;
1493 rq
->avg_load_per_task
= 0;
1495 return rq
->avg_load_per_task
;
1498 #ifdef CONFIG_FAIR_GROUP_SCHED
1500 static __read_mostly
unsigned long *update_shares_data
;
1502 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1505 * Calculate and set the cpu's group shares.
1507 static void update_group_shares_cpu(struct task_group
*tg
, int cpu
,
1508 unsigned long sd_shares
,
1509 unsigned long sd_rq_weight
,
1510 unsigned long *usd_rq_weight
)
1512 unsigned long shares
, rq_weight
;
1515 rq_weight
= usd_rq_weight
[cpu
];
1518 rq_weight
= NICE_0_LOAD
;
1522 * \Sum_j shares_j * rq_weight_i
1523 * shares_i = -----------------------------
1524 * \Sum_j rq_weight_j
1526 shares
= (sd_shares
* rq_weight
) / sd_rq_weight
;
1527 shares
= clamp_t(unsigned long, shares
, MIN_SHARES
, MAX_SHARES
);
1529 if (abs(shares
- tg
->se
[cpu
]->load
.weight
) >
1530 sysctl_sched_shares_thresh
) {
1531 struct rq
*rq
= cpu_rq(cpu
);
1532 unsigned long flags
;
1534 raw_spin_lock_irqsave(&rq
->lock
, flags
);
1535 tg
->cfs_rq
[cpu
]->rq_weight
= boost
? 0 : rq_weight
;
1536 tg
->cfs_rq
[cpu
]->shares
= boost
? 0 : shares
;
1537 __set_se_shares(tg
->se
[cpu
], shares
);
1538 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
1543 * Re-compute the task group their per cpu shares over the given domain.
1544 * This needs to be done in a bottom-up fashion because the rq weight of a
1545 * parent group depends on the shares of its child groups.
1547 static int tg_shares_up(struct task_group
*tg
, void *data
)
1549 unsigned long weight
, rq_weight
= 0, sum_weight
= 0, shares
= 0;
1550 unsigned long *usd_rq_weight
;
1551 struct sched_domain
*sd
= data
;
1552 unsigned long flags
;
1558 local_irq_save(flags
);
1559 usd_rq_weight
= per_cpu_ptr(update_shares_data
, smp_processor_id());
1561 for_each_cpu(i
, sched_domain_span(sd
)) {
1562 weight
= tg
->cfs_rq
[i
]->load
.weight
;
1563 usd_rq_weight
[i
] = weight
;
1565 rq_weight
+= weight
;
1567 * If there are currently no tasks on the cpu pretend there
1568 * is one of average load so that when a new task gets to
1569 * run here it will not get delayed by group starvation.
1572 weight
= NICE_0_LOAD
;
1574 sum_weight
+= weight
;
1575 shares
+= tg
->cfs_rq
[i
]->shares
;
1579 rq_weight
= sum_weight
;
1581 if ((!shares
&& rq_weight
) || shares
> tg
->shares
)
1582 shares
= tg
->shares
;
1584 if (!sd
->parent
|| !(sd
->parent
->flags
& SD_LOAD_BALANCE
))
1585 shares
= tg
->shares
;
1587 for_each_cpu(i
, sched_domain_span(sd
))
1588 update_group_shares_cpu(tg
, i
, shares
, rq_weight
, usd_rq_weight
);
1590 local_irq_restore(flags
);
1596 * Compute the cpu's hierarchical load factor for each task group.
1597 * This needs to be done in a top-down fashion because the load of a child
1598 * group is a fraction of its parents load.
1600 static int tg_load_down(struct task_group
*tg
, void *data
)
1603 long cpu
= (long)data
;
1606 load
= cpu_rq(cpu
)->load
.weight
;
1608 load
= tg
->parent
->cfs_rq
[cpu
]->h_load
;
1609 load
*= tg
->cfs_rq
[cpu
]->shares
;
1610 load
/= tg
->parent
->cfs_rq
[cpu
]->load
.weight
+ 1;
1613 tg
->cfs_rq
[cpu
]->h_load
= load
;
1618 static void update_shares(struct sched_domain
*sd
)
1623 if (root_task_group_empty())
1626 now
= cpu_clock(raw_smp_processor_id());
1627 elapsed
= now
- sd
->last_update
;
1629 if (elapsed
>= (s64
)(u64
)sysctl_sched_shares_ratelimit
) {
1630 sd
->last_update
= now
;
1631 walk_tg_tree(tg_nop
, tg_shares_up
, sd
);
1635 static void update_h_load(long cpu
)
1637 if (root_task_group_empty())
1640 walk_tg_tree(tg_load_down
, tg_nop
, (void *)cpu
);
1645 static inline void update_shares(struct sched_domain
*sd
)
1651 #ifdef CONFIG_PREEMPT
1653 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
);
1656 * fair double_lock_balance: Safely acquires both rq->locks in a fair
1657 * way at the expense of forcing extra atomic operations in all
1658 * invocations. This assures that the double_lock is acquired using the
1659 * same underlying policy as the spinlock_t on this architecture, which
1660 * reduces latency compared to the unfair variant below. However, it
1661 * also adds more overhead and therefore may reduce throughput.
1663 static inline int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1664 __releases(this_rq
->lock
)
1665 __acquires(busiest
->lock
)
1666 __acquires(this_rq
->lock
)
1668 raw_spin_unlock(&this_rq
->lock
);
1669 double_rq_lock(this_rq
, busiest
);
1676 * Unfair double_lock_balance: Optimizes throughput at the expense of
1677 * latency by eliminating extra atomic operations when the locks are
1678 * already in proper order on entry. This favors lower cpu-ids and will
1679 * grant the double lock to lower cpus over higher ids under contention,
1680 * regardless of entry order into the function.
1682 static int _double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1683 __releases(this_rq
->lock
)
1684 __acquires(busiest
->lock
)
1685 __acquires(this_rq
->lock
)
1689 if (unlikely(!raw_spin_trylock(&busiest
->lock
))) {
1690 if (busiest
< this_rq
) {
1691 raw_spin_unlock(&this_rq
->lock
);
1692 raw_spin_lock(&busiest
->lock
);
1693 raw_spin_lock_nested(&this_rq
->lock
,
1694 SINGLE_DEPTH_NESTING
);
1697 raw_spin_lock_nested(&busiest
->lock
,
1698 SINGLE_DEPTH_NESTING
);
1703 #endif /* CONFIG_PREEMPT */
1706 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1708 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1710 if (unlikely(!irqs_disabled())) {
1711 /* printk() doesn't work good under rq->lock */
1712 raw_spin_unlock(&this_rq
->lock
);
1716 return _double_lock_balance(this_rq
, busiest
);
1719 static inline void double_unlock_balance(struct rq
*this_rq
, struct rq
*busiest
)
1720 __releases(busiest
->lock
)
1722 raw_spin_unlock(&busiest
->lock
);
1723 lock_set_subclass(&this_rq
->lock
.dep_map
, 0, _RET_IP_
);
1727 * double_rq_lock - safely lock two runqueues
1729 * Note this does not disable interrupts like task_rq_lock,
1730 * you need to do so manually before calling.
1732 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
1733 __acquires(rq1
->lock
)
1734 __acquires(rq2
->lock
)
1736 BUG_ON(!irqs_disabled());
1738 raw_spin_lock(&rq1
->lock
);
1739 __acquire(rq2
->lock
); /* Fake it out ;) */
1742 raw_spin_lock(&rq1
->lock
);
1743 raw_spin_lock_nested(&rq2
->lock
, SINGLE_DEPTH_NESTING
);
1745 raw_spin_lock(&rq2
->lock
);
1746 raw_spin_lock_nested(&rq1
->lock
, SINGLE_DEPTH_NESTING
);
1749 update_rq_clock(rq1
);
1750 update_rq_clock(rq2
);
1754 * double_rq_unlock - safely unlock two runqueues
1756 * Note this does not restore interrupts like task_rq_unlock,
1757 * you need to do so manually after calling.
1759 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
1760 __releases(rq1
->lock
)
1761 __releases(rq2
->lock
)
1763 raw_spin_unlock(&rq1
->lock
);
1765 raw_spin_unlock(&rq2
->lock
);
1767 __release(rq2
->lock
);
1772 #ifdef CONFIG_FAIR_GROUP_SCHED
1773 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1776 cfs_rq
->shares
= shares
;
1781 static void calc_load_account_active(struct rq
*this_rq
);
1782 static void update_sysctl(void);
1783 static int get_update_sysctl_factor(void);
1785 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1787 set_task_rq(p
, cpu
);
1790 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1791 * successfuly executed on another CPU. We must ensure that updates of
1792 * per-task data have been completed by this moment.
1795 task_thread_info(p
)->cpu
= cpu
;
1799 static const struct sched_class rt_sched_class
;
1801 #define sched_class_highest (&rt_sched_class)
1802 #define for_each_class(class) \
1803 for (class = sched_class_highest; class; class = class->next)
1805 #include "sched_stats.h"
1807 static void inc_nr_running(struct rq
*rq
)
1812 static void dec_nr_running(struct rq
*rq
)
1817 static void set_load_weight(struct task_struct
*p
)
1819 if (task_has_rt_policy(p
)) {
1820 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1821 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1826 * SCHED_IDLE tasks get minimal weight:
1828 if (p
->policy
== SCHED_IDLE
) {
1829 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1830 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1834 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1835 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1838 static void update_avg(u64
*avg
, u64 sample
)
1840 s64 diff
= sample
- *avg
;
1845 enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
, bool head
)
1848 p
->se
.start_runtime
= p
->se
.sum_exec_runtime
;
1850 sched_info_queued(p
);
1851 p
->sched_class
->enqueue_task(rq
, p
, wakeup
, head
);
1855 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1858 if (p
->se
.last_wakeup
) {
1859 update_avg(&p
->se
.avg_overlap
,
1860 p
->se
.sum_exec_runtime
- p
->se
.last_wakeup
);
1861 p
->se
.last_wakeup
= 0;
1863 update_avg(&p
->se
.avg_wakeup
,
1864 sysctl_sched_wakeup_granularity
);
1868 sched_info_dequeued(p
);
1869 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1874 * activate_task - move a task to the runqueue.
1876 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1878 if (task_contributes_to_load(p
))
1879 rq
->nr_uninterruptible
--;
1881 enqueue_task(rq
, p
, wakeup
, false);
1886 * deactivate_task - remove a task from the runqueue.
1888 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1890 if (task_contributes_to_load(p
))
1891 rq
->nr_uninterruptible
++;
1893 dequeue_task(rq
, p
, sleep
);
1897 #include "sched_idletask.c"
1898 #include "sched_fair.c"
1899 #include "sched_rt.c"
1900 #ifdef CONFIG_SCHED_DEBUG
1901 # include "sched_debug.c"
1905 * __normal_prio - return the priority that is based on the static prio
1907 static inline int __normal_prio(struct task_struct
*p
)
1909 return p
->static_prio
;
1913 * Calculate the expected normal priority: i.e. priority
1914 * without taking RT-inheritance into account. Might be
1915 * boosted by interactivity modifiers. Changes upon fork,
1916 * setprio syscalls, and whenever the interactivity
1917 * estimator recalculates.
1919 static inline int normal_prio(struct task_struct
*p
)
1923 if (task_has_rt_policy(p
))
1924 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1926 prio
= __normal_prio(p
);
1931 * Calculate the current priority, i.e. the priority
1932 * taken into account by the scheduler. This value might
1933 * be boosted by RT tasks, or might be boosted by
1934 * interactivity modifiers. Will be RT if the task got
1935 * RT-boosted. If not then it returns p->normal_prio.
1937 static int effective_prio(struct task_struct
*p
)
1939 p
->normal_prio
= normal_prio(p
);
1941 * If we are RT tasks or we were boosted to RT priority,
1942 * keep the priority unchanged. Otherwise, update priority
1943 * to the normal priority:
1945 if (!rt_prio(p
->prio
))
1946 return p
->normal_prio
;
1951 * task_curr - is this task currently executing on a CPU?
1952 * @p: the task in question.
1954 inline int task_curr(const struct task_struct
*p
)
1956 return cpu_curr(task_cpu(p
)) == p
;
1959 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1960 const struct sched_class
*prev_class
,
1961 int oldprio
, int running
)
1963 if (prev_class
!= p
->sched_class
) {
1964 if (prev_class
->switched_from
)
1965 prev_class
->switched_from(rq
, p
, running
);
1966 p
->sched_class
->switched_to(rq
, p
, running
);
1968 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1973 * Is this task likely cache-hot:
1976 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1980 if (p
->sched_class
!= &fair_sched_class
)
1984 * Buddy candidates are cache hot:
1986 if (sched_feat(CACHE_HOT_BUDDY
) && this_rq()->nr_running
&&
1987 (&p
->se
== cfs_rq_of(&p
->se
)->next
||
1988 &p
->se
== cfs_rq_of(&p
->se
)->last
))
1991 if (sysctl_sched_migration_cost
== -1)
1993 if (sysctl_sched_migration_cost
== 0)
1996 delta
= now
- p
->se
.exec_start
;
1998 return delta
< (s64
)sysctl_sched_migration_cost
;
2001 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2003 #ifdef CONFIG_SCHED_DEBUG
2005 * We should never call set_task_cpu() on a blocked task,
2006 * ttwu() will sort out the placement.
2008 WARN_ON_ONCE(p
->state
!= TASK_RUNNING
&& p
->state
!= TASK_WAKING
&&
2009 !(task_thread_info(p
)->preempt_count
& PREEMPT_ACTIVE
));
2012 trace_sched_migrate_task(p
, new_cpu
);
2014 if (task_cpu(p
) != new_cpu
) {
2015 p
->se
.nr_migrations
++;
2016 perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS
, 1, 1, NULL
, 0);
2019 __set_task_cpu(p
, new_cpu
);
2022 struct migration_req
{
2023 struct list_head list
;
2025 struct task_struct
*task
;
2028 struct completion done
;
2032 * The task's runqueue lock must be held.
2033 * Returns true if you have to wait for migration thread.
2036 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
2038 struct rq
*rq
= task_rq(p
);
2041 * If the task is not on a runqueue (and not running), then
2042 * the next wake-up will properly place the task.
2044 if (!p
->se
.on_rq
&& !task_running(rq
, p
))
2047 init_completion(&req
->done
);
2049 req
->dest_cpu
= dest_cpu
;
2050 list_add(&req
->list
, &rq
->migration_queue
);
2056 * wait_task_context_switch - wait for a thread to complete at least one
2059 * @p must not be current.
2061 void wait_task_context_switch(struct task_struct
*p
)
2063 unsigned long nvcsw
, nivcsw
, flags
;
2071 * The runqueue is assigned before the actual context
2072 * switch. We need to take the runqueue lock.
2074 * We could check initially without the lock but it is
2075 * very likely that we need to take the lock in every
2078 rq
= task_rq_lock(p
, &flags
);
2079 running
= task_running(rq
, p
);
2080 task_rq_unlock(rq
, &flags
);
2082 if (likely(!running
))
2085 * The switch count is incremented before the actual
2086 * context switch. We thus wait for two switches to be
2087 * sure at least one completed.
2089 if ((p
->nvcsw
- nvcsw
) > 1)
2091 if ((p
->nivcsw
- nivcsw
) > 1)
2099 * wait_task_inactive - wait for a thread to unschedule.
2101 * If @match_state is nonzero, it's the @p->state value just checked and
2102 * not expected to change. If it changes, i.e. @p might have woken up,
2103 * then return zero. When we succeed in waiting for @p to be off its CPU,
2104 * we return a positive number (its total switch count). If a second call
2105 * a short while later returns the same number, the caller can be sure that
2106 * @p has remained unscheduled the whole time.
2108 * The caller must ensure that the task *will* unschedule sometime soon,
2109 * else this function might spin for a *long* time. This function can't
2110 * be called with interrupts off, or it may introduce deadlock with
2111 * smp_call_function() if an IPI is sent by the same process we are
2112 * waiting to become inactive.
2114 unsigned long wait_task_inactive(struct task_struct
*p
, long match_state
)
2116 unsigned long flags
;
2123 * We do the initial early heuristics without holding
2124 * any task-queue locks at all. We'll only try to get
2125 * the runqueue lock when things look like they will
2131 * If the task is actively running on another CPU
2132 * still, just relax and busy-wait without holding
2135 * NOTE! Since we don't hold any locks, it's not
2136 * even sure that "rq" stays as the right runqueue!
2137 * But we don't care, since "task_running()" will
2138 * return false if the runqueue has changed and p
2139 * is actually now running somewhere else!
2141 while (task_running(rq
, p
)) {
2142 if (match_state
&& unlikely(p
->state
!= match_state
))
2148 * Ok, time to look more closely! We need the rq
2149 * lock now, to be *sure*. If we're wrong, we'll
2150 * just go back and repeat.
2152 rq
= task_rq_lock(p
, &flags
);
2153 trace_sched_wait_task(rq
, p
);
2154 running
= task_running(rq
, p
);
2155 on_rq
= p
->se
.on_rq
;
2157 if (!match_state
|| p
->state
== match_state
)
2158 ncsw
= p
->nvcsw
| LONG_MIN
; /* sets MSB */
2159 task_rq_unlock(rq
, &flags
);
2162 * If it changed from the expected state, bail out now.
2164 if (unlikely(!ncsw
))
2168 * Was it really running after all now that we
2169 * checked with the proper locks actually held?
2171 * Oops. Go back and try again..
2173 if (unlikely(running
)) {
2179 * It's not enough that it's not actively running,
2180 * it must be off the runqueue _entirely_, and not
2183 * So if it was still runnable (but just not actively
2184 * running right now), it's preempted, and we should
2185 * yield - it could be a while.
2187 if (unlikely(on_rq
)) {
2188 schedule_timeout_uninterruptible(1);
2193 * Ahh, all good. It wasn't running, and it wasn't
2194 * runnable, which means that it will never become
2195 * running in the future either. We're all done!
2204 * kick_process - kick a running thread to enter/exit the kernel
2205 * @p: the to-be-kicked thread
2207 * Cause a process which is running on another CPU to enter
2208 * kernel-mode, without any delay. (to get signals handled.)
2210 * NOTE: this function doesnt have to take the runqueue lock,
2211 * because all it wants to ensure is that the remote task enters
2212 * the kernel. If the IPI races and the task has been migrated
2213 * to another CPU then no harm is done and the purpose has been
2216 void kick_process(struct task_struct
*p
)
2222 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2223 smp_send_reschedule(cpu
);
2226 EXPORT_SYMBOL_GPL(kick_process
);
2227 #endif /* CONFIG_SMP */
2230 * task_oncpu_function_call - call a function on the cpu on which a task runs
2231 * @p: the task to evaluate
2232 * @func: the function to be called
2233 * @info: the function call argument
2235 * Calls the function @func when the task is currently running. This might
2236 * be on the current CPU, which just calls the function directly
2238 void task_oncpu_function_call(struct task_struct
*p
,
2239 void (*func
) (void *info
), void *info
)
2246 smp_call_function_single(cpu
, func
, info
, 1);
2251 static int select_fallback_rq(int cpu
, struct task_struct
*p
)
2254 const struct cpumask
*nodemask
= cpumask_of_node(cpu_to_node(cpu
));
2256 /* Look for allowed, online CPU in same node. */
2257 for_each_cpu_and(dest_cpu
, nodemask
, cpu_active_mask
)
2258 if (cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
2261 /* Any allowed, online CPU? */
2262 dest_cpu
= cpumask_any_and(&p
->cpus_allowed
, cpu_active_mask
);
2263 if (dest_cpu
< nr_cpu_ids
)
2266 /* No more Mr. Nice Guy. */
2267 if (dest_cpu
>= nr_cpu_ids
) {
2269 cpuset_cpus_allowed_locked(p
, &p
->cpus_allowed
);
2271 dest_cpu
= cpumask_any_and(cpu_active_mask
, &p
->cpus_allowed
);
2274 * Don't tell them about moving exiting tasks or
2275 * kernel threads (both mm NULL), since they never
2278 if (p
->mm
&& printk_ratelimit()) {
2279 printk(KERN_INFO
"process %d (%s) no "
2280 "longer affine to cpu%d\n",
2281 task_pid_nr(p
), p
->comm
, cpu
);
2291 * - fork, @p is stable because it isn't on the tasklist yet
2293 * - exec, @p is unstable, retry loop
2295 * - wake-up, we serialize ->cpus_allowed against TASK_WAKING so
2296 * we should be good.
2299 int select_task_rq(struct task_struct
*p
, int sd_flags
, int wake_flags
)
2301 int cpu
= p
->sched_class
->select_task_rq(p
, sd_flags
, wake_flags
);
2304 * In order not to call set_task_cpu() on a blocking task we need
2305 * to rely on ttwu() to place the task on a valid ->cpus_allowed
2308 * Since this is common to all placement strategies, this lives here.
2310 * [ this allows ->select_task() to simply return task_cpu(p) and
2311 * not worry about this generic constraint ]
2313 if (unlikely(!cpumask_test_cpu(cpu
, &p
->cpus_allowed
) ||
2315 cpu
= select_fallback_rq(task_cpu(p
), p
);
2322 * try_to_wake_up - wake up a thread
2323 * @p: the to-be-woken-up thread
2324 * @state: the mask of task states that can be woken
2325 * @sync: do a synchronous wakeup?
2327 * Put it on the run-queue if it's not already there. The "current"
2328 * thread is always on the run-queue (except when the actual
2329 * re-schedule is in progress), and as such you're allowed to do
2330 * the simpler "current->state = TASK_RUNNING" to mark yourself
2331 * runnable without the overhead of this.
2333 * returns failure only if the task is already active.
2335 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
,
2338 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2339 unsigned long flags
;
2340 struct rq
*rq
, *orig_rq
;
2342 if (!sched_feat(SYNC_WAKEUPS
))
2343 wake_flags
&= ~WF_SYNC
;
2345 this_cpu
= get_cpu();
2348 rq
= orig_rq
= task_rq_lock(p
, &flags
);
2349 update_rq_clock(rq
);
2350 if (!(p
->state
& state
))
2360 if (unlikely(task_running(rq
, p
)))
2364 * In order to handle concurrent wakeups and release the rq->lock
2365 * we put the task in TASK_WAKING state.
2367 * First fix up the nr_uninterruptible count:
2369 if (task_contributes_to_load(p
))
2370 rq
->nr_uninterruptible
--;
2371 p
->state
= TASK_WAKING
;
2373 if (p
->sched_class
->task_waking
)
2374 p
->sched_class
->task_waking(rq
, p
);
2376 __task_rq_unlock(rq
);
2378 cpu
= select_task_rq(p
, SD_BALANCE_WAKE
, wake_flags
);
2379 if (cpu
!= orig_cpu
)
2380 set_task_cpu(p
, cpu
);
2382 rq
= __task_rq_lock(p
);
2383 update_rq_clock(rq
);
2385 WARN_ON(p
->state
!= TASK_WAKING
);
2388 #ifdef CONFIG_SCHEDSTATS
2389 schedstat_inc(rq
, ttwu_count
);
2390 if (cpu
== this_cpu
)
2391 schedstat_inc(rq
, ttwu_local
);
2393 struct sched_domain
*sd
;
2394 for_each_domain(this_cpu
, sd
) {
2395 if (cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
2396 schedstat_inc(sd
, ttwu_wake_remote
);
2401 #endif /* CONFIG_SCHEDSTATS */
2404 #endif /* CONFIG_SMP */
2405 schedstat_inc(p
, se
.nr_wakeups
);
2406 if (wake_flags
& WF_SYNC
)
2407 schedstat_inc(p
, se
.nr_wakeups_sync
);
2408 if (orig_cpu
!= cpu
)
2409 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2410 if (cpu
== this_cpu
)
2411 schedstat_inc(p
, se
.nr_wakeups_local
);
2413 schedstat_inc(p
, se
.nr_wakeups_remote
);
2414 activate_task(rq
, p
, 1);
2418 * Only attribute actual wakeups done by this task.
2420 if (!in_interrupt()) {
2421 struct sched_entity
*se
= ¤t
->se
;
2422 u64 sample
= se
->sum_exec_runtime
;
2424 if (se
->last_wakeup
)
2425 sample
-= se
->last_wakeup
;
2427 sample
-= se
->start_runtime
;
2428 update_avg(&se
->avg_wakeup
, sample
);
2430 se
->last_wakeup
= se
->sum_exec_runtime
;
2434 trace_sched_wakeup(rq
, p
, success
);
2435 check_preempt_curr(rq
, p
, wake_flags
);
2437 p
->state
= TASK_RUNNING
;
2439 if (p
->sched_class
->task_woken
)
2440 p
->sched_class
->task_woken(rq
, p
);
2442 if (unlikely(rq
->idle_stamp
)) {
2443 u64 delta
= rq
->clock
- rq
->idle_stamp
;
2444 u64 max
= 2*sysctl_sched_migration_cost
;
2449 update_avg(&rq
->avg_idle
, delta
);
2454 task_rq_unlock(rq
, &flags
);
2461 * wake_up_process - Wake up a specific process
2462 * @p: The process to be woken up.
2464 * Attempt to wake up the nominated process and move it to the set of runnable
2465 * processes. Returns 1 if the process was woken up, 0 if it was already
2468 * It may be assumed that this function implies a write memory barrier before
2469 * changing the task state if and only if any tasks are woken up.
2471 int wake_up_process(struct task_struct
*p
)
2473 return try_to_wake_up(p
, TASK_ALL
, 0);
2475 EXPORT_SYMBOL(wake_up_process
);
2477 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2479 return try_to_wake_up(p
, state
, 0);
2483 * Perform scheduler related setup for a newly forked process p.
2484 * p is forked by current.
2486 * __sched_fork() is basic setup used by init_idle() too:
2488 static void __sched_fork(struct task_struct
*p
)
2490 p
->se
.exec_start
= 0;
2491 p
->se
.sum_exec_runtime
= 0;
2492 p
->se
.prev_sum_exec_runtime
= 0;
2493 p
->se
.nr_migrations
= 0;
2494 p
->se
.last_wakeup
= 0;
2495 p
->se
.avg_overlap
= 0;
2496 p
->se
.start_runtime
= 0;
2497 p
->se
.avg_wakeup
= sysctl_sched_wakeup_granularity
;
2499 #ifdef CONFIG_SCHEDSTATS
2500 p
->se
.wait_start
= 0;
2502 p
->se
.wait_count
= 0;
2505 p
->se
.sleep_start
= 0;
2506 p
->se
.sleep_max
= 0;
2507 p
->se
.sum_sleep_runtime
= 0;
2509 p
->se
.block_start
= 0;
2510 p
->se
.block_max
= 0;
2512 p
->se
.slice_max
= 0;
2514 p
->se
.nr_migrations_cold
= 0;
2515 p
->se
.nr_failed_migrations_affine
= 0;
2516 p
->se
.nr_failed_migrations_running
= 0;
2517 p
->se
.nr_failed_migrations_hot
= 0;
2518 p
->se
.nr_forced_migrations
= 0;
2520 p
->se
.nr_wakeups
= 0;
2521 p
->se
.nr_wakeups_sync
= 0;
2522 p
->se
.nr_wakeups_migrate
= 0;
2523 p
->se
.nr_wakeups_local
= 0;
2524 p
->se
.nr_wakeups_remote
= 0;
2525 p
->se
.nr_wakeups_affine
= 0;
2526 p
->se
.nr_wakeups_affine_attempts
= 0;
2527 p
->se
.nr_wakeups_passive
= 0;
2528 p
->se
.nr_wakeups_idle
= 0;
2532 INIT_LIST_HEAD(&p
->rt
.run_list
);
2534 INIT_LIST_HEAD(&p
->se
.group_node
);
2536 #ifdef CONFIG_PREEMPT_NOTIFIERS
2537 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2542 * fork()/clone()-time setup:
2544 void sched_fork(struct task_struct
*p
, int clone_flags
)
2546 int cpu
= get_cpu();
2550 * We mark the process as waking here. This guarantees that
2551 * nobody will actually run it, and a signal or other external
2552 * event cannot wake it up and insert it on the runqueue either.
2554 p
->state
= TASK_WAKING
;
2557 * Revert to default priority/policy on fork if requested.
2559 if (unlikely(p
->sched_reset_on_fork
)) {
2560 if (p
->policy
== SCHED_FIFO
|| p
->policy
== SCHED_RR
) {
2561 p
->policy
= SCHED_NORMAL
;
2562 p
->normal_prio
= p
->static_prio
;
2565 if (PRIO_TO_NICE(p
->static_prio
) < 0) {
2566 p
->static_prio
= NICE_TO_PRIO(0);
2567 p
->normal_prio
= p
->static_prio
;
2572 * We don't need the reset flag anymore after the fork. It has
2573 * fulfilled its duty:
2575 p
->sched_reset_on_fork
= 0;
2579 * Make sure we do not leak PI boosting priority to the child.
2581 p
->prio
= current
->normal_prio
;
2583 if (!rt_prio(p
->prio
))
2584 p
->sched_class
= &fair_sched_class
;
2586 if (p
->sched_class
->task_fork
)
2587 p
->sched_class
->task_fork(p
);
2590 cpu
= select_task_rq(p
, SD_BALANCE_FORK
, 0);
2592 set_task_cpu(p
, cpu
);
2594 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2595 if (likely(sched_info_on()))
2596 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2598 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2601 #ifdef CONFIG_PREEMPT
2602 /* Want to start with kernel preemption disabled. */
2603 task_thread_info(p
)->preempt_count
= 1;
2605 plist_node_init(&p
->pushable_tasks
, MAX_PRIO
);
2611 * wake_up_new_task - wake up a newly created task for the first time.
2613 * This function will do some initial scheduler statistics housekeeping
2614 * that must be done for every newly created context, then puts the task
2615 * on the runqueue and wakes it.
2617 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2619 unsigned long flags
;
2622 rq
= task_rq_lock(p
, &flags
);
2623 BUG_ON(p
->state
!= TASK_WAKING
);
2624 p
->state
= TASK_RUNNING
;
2625 update_rq_clock(rq
);
2626 activate_task(rq
, p
, 0);
2627 trace_sched_wakeup_new(rq
, p
, 1);
2628 check_preempt_curr(rq
, p
, WF_FORK
);
2630 if (p
->sched_class
->task_woken
)
2631 p
->sched_class
->task_woken(rq
, p
);
2633 task_rq_unlock(rq
, &flags
);
2636 #ifdef CONFIG_PREEMPT_NOTIFIERS
2639 * preempt_notifier_register - tell me when current is being preempted & rescheduled
2640 * @notifier: notifier struct to register
2642 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2644 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2646 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2649 * preempt_notifier_unregister - no longer interested in preemption notifications
2650 * @notifier: notifier struct to unregister
2652 * This is safe to call from within a preemption notifier.
2654 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2656 hlist_del(¬ifier
->link
);
2658 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2660 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2662 struct preempt_notifier
*notifier
;
2663 struct hlist_node
*node
;
2665 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2666 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2670 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2671 struct task_struct
*next
)
2673 struct preempt_notifier
*notifier
;
2674 struct hlist_node
*node
;
2676 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2677 notifier
->ops
->sched_out(notifier
, next
);
2680 #else /* !CONFIG_PREEMPT_NOTIFIERS */
2682 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2687 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2688 struct task_struct
*next
)
2692 #endif /* CONFIG_PREEMPT_NOTIFIERS */
2695 * prepare_task_switch - prepare to switch tasks
2696 * @rq: the runqueue preparing to switch
2697 * @prev: the current task that is being switched out
2698 * @next: the task we are going to switch to.
2700 * This is called with the rq lock held and interrupts off. It must
2701 * be paired with a subsequent finish_task_switch after the context
2704 * prepare_task_switch sets up locking and calls architecture specific
2708 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2709 struct task_struct
*next
)
2711 fire_sched_out_preempt_notifiers(prev
, next
);
2712 prepare_lock_switch(rq
, next
);
2713 prepare_arch_switch(next
);
2717 * finish_task_switch - clean up after a task-switch
2718 * @rq: runqueue associated with task-switch
2719 * @prev: the thread we just switched away from.
2721 * finish_task_switch must be called after the context switch, paired
2722 * with a prepare_task_switch call before the context switch.
2723 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2724 * and do any other architecture-specific cleanup actions.
2726 * Note that we may have delayed dropping an mm in context_switch(). If
2727 * so, we finish that here outside of the runqueue lock. (Doing it
2728 * with the lock held can cause deadlocks; see schedule() for
2731 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2732 __releases(rq
->lock
)
2734 struct mm_struct
*mm
= rq
->prev_mm
;
2740 * A task struct has one reference for the use as "current".
2741 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2742 * schedule one last time. The schedule call will never return, and
2743 * the scheduled task must drop that reference.
2744 * The test for TASK_DEAD must occur while the runqueue locks are
2745 * still held, otherwise prev could be scheduled on another cpu, die
2746 * there before we look at prev->state, and then the reference would
2748 * Manfred Spraul <manfred@colorfullife.com>
2750 prev_state
= prev
->state
;
2751 finish_arch_switch(prev
);
2752 perf_event_task_sched_in(current
, cpu_of(rq
));
2753 finish_lock_switch(rq
, prev
);
2755 fire_sched_in_preempt_notifiers(current
);
2758 if (unlikely(prev_state
== TASK_DEAD
)) {
2760 * Remove function-return probe instances associated with this
2761 * task and put them back on the free list.
2763 kprobe_flush_task(prev
);
2764 put_task_struct(prev
);
2770 /* assumes rq->lock is held */
2771 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*prev
)
2773 if (prev
->sched_class
->pre_schedule
)
2774 prev
->sched_class
->pre_schedule(rq
, prev
);
2777 /* rq->lock is NOT held, but preemption is disabled */
2778 static inline void post_schedule(struct rq
*rq
)
2780 if (rq
->post_schedule
) {
2781 unsigned long flags
;
2783 raw_spin_lock_irqsave(&rq
->lock
, flags
);
2784 if (rq
->curr
->sched_class
->post_schedule
)
2785 rq
->curr
->sched_class
->post_schedule(rq
);
2786 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
2788 rq
->post_schedule
= 0;
2794 static inline void pre_schedule(struct rq
*rq
, struct task_struct
*p
)
2798 static inline void post_schedule(struct rq
*rq
)
2805 * schedule_tail - first thing a freshly forked thread must call.
2806 * @prev: the thread we just switched away from.
2808 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2809 __releases(rq
->lock
)
2811 struct rq
*rq
= this_rq();
2813 finish_task_switch(rq
, prev
);
2816 * FIXME: do we need to worry about rq being invalidated by the
2821 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2822 /* In this case, finish_task_switch does not reenable preemption */
2825 if (current
->set_child_tid
)
2826 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2830 * context_switch - switch to the new MM and the new
2831 * thread's register state.
2834 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2835 struct task_struct
*next
)
2837 struct mm_struct
*mm
, *oldmm
;
2839 prepare_task_switch(rq
, prev
, next
);
2840 trace_sched_switch(rq
, prev
, next
);
2842 oldmm
= prev
->active_mm
;
2844 * For paravirt, this is coupled with an exit in switch_to to
2845 * combine the page table reload and the switch backend into
2848 arch_start_context_switch(prev
);
2851 next
->active_mm
= oldmm
;
2852 atomic_inc(&oldmm
->mm_count
);
2853 enter_lazy_tlb(oldmm
, next
);
2855 switch_mm(oldmm
, mm
, next
);
2857 if (likely(!prev
->mm
)) {
2858 prev
->active_mm
= NULL
;
2859 rq
->prev_mm
= oldmm
;
2862 * Since the runqueue lock will be released by the next
2863 * task (which is an invalid locking op but in the case
2864 * of the scheduler it's an obvious special-case), so we
2865 * do an early lockdep release here:
2867 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2868 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2871 /* Here we just switch the register state and the stack. */
2872 switch_to(prev
, next
, prev
);
2876 * this_rq must be evaluated again because prev may have moved
2877 * CPUs since it called schedule(), thus the 'rq' on its stack
2878 * frame will be invalid.
2880 finish_task_switch(this_rq(), prev
);
2884 * nr_running, nr_uninterruptible and nr_context_switches:
2886 * externally visible scheduler statistics: current number of runnable
2887 * threads, current number of uninterruptible-sleeping threads, total
2888 * number of context switches performed since bootup.
2890 unsigned long nr_running(void)
2892 unsigned long i
, sum
= 0;
2894 for_each_online_cpu(i
)
2895 sum
+= cpu_rq(i
)->nr_running
;
2900 unsigned long nr_uninterruptible(void)
2902 unsigned long i
, sum
= 0;
2904 for_each_possible_cpu(i
)
2905 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2908 * Since we read the counters lockless, it might be slightly
2909 * inaccurate. Do not allow it to go below zero though:
2911 if (unlikely((long)sum
< 0))
2917 unsigned long long nr_context_switches(void)
2920 unsigned long long sum
= 0;
2922 for_each_possible_cpu(i
)
2923 sum
+= cpu_rq(i
)->nr_switches
;
2928 unsigned long nr_iowait(void)
2930 unsigned long i
, sum
= 0;
2932 for_each_possible_cpu(i
)
2933 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2938 unsigned long nr_iowait_cpu(void)
2940 struct rq
*this = this_rq();
2941 return atomic_read(&this->nr_iowait
);
2944 unsigned long this_cpu_load(void)
2946 struct rq
*this = this_rq();
2947 return this->cpu_load
[0];
2951 /* Variables and functions for calc_load */
2952 static atomic_long_t calc_load_tasks
;
2953 static unsigned long calc_load_update
;
2954 unsigned long avenrun
[3];
2955 EXPORT_SYMBOL(avenrun
);
2958 * get_avenrun - get the load average array
2959 * @loads: pointer to dest load array
2960 * @offset: offset to add
2961 * @shift: shift count to shift the result left
2963 * These values are estimates at best, so no need for locking.
2965 void get_avenrun(unsigned long *loads
, unsigned long offset
, int shift
)
2967 loads
[0] = (avenrun
[0] + offset
) << shift
;
2968 loads
[1] = (avenrun
[1] + offset
) << shift
;
2969 loads
[2] = (avenrun
[2] + offset
) << shift
;
2972 static unsigned long
2973 calc_load(unsigned long load
, unsigned long exp
, unsigned long active
)
2976 load
+= active
* (FIXED_1
- exp
);
2977 return load
>> FSHIFT
;
2981 * calc_load - update the avenrun load estimates 10 ticks after the
2982 * CPUs have updated calc_load_tasks.
2984 void calc_global_load(void)
2986 unsigned long upd
= calc_load_update
+ 10;
2989 if (time_before(jiffies
, upd
))
2992 active
= atomic_long_read(&calc_load_tasks
);
2993 active
= active
> 0 ? active
* FIXED_1
: 0;
2995 avenrun
[0] = calc_load(avenrun
[0], EXP_1
, active
);
2996 avenrun
[1] = calc_load(avenrun
[1], EXP_5
, active
);
2997 avenrun
[2] = calc_load(avenrun
[2], EXP_15
, active
);
2999 calc_load_update
+= LOAD_FREQ
;
3003 * Either called from update_cpu_load() or from a cpu going idle
3005 static void calc_load_account_active(struct rq
*this_rq
)
3007 long nr_active
, delta
;
3009 nr_active
= this_rq
->nr_running
;
3010 nr_active
+= (long) this_rq
->nr_uninterruptible
;
3012 if (nr_active
!= this_rq
->calc_load_active
) {
3013 delta
= nr_active
- this_rq
->calc_load_active
;
3014 this_rq
->calc_load_active
= nr_active
;
3015 atomic_long_add(delta
, &calc_load_tasks
);
3020 * Update rq->cpu_load[] statistics. This function is usually called every
3021 * scheduler tick (TICK_NSEC).
3023 static void update_cpu_load(struct rq
*this_rq
)
3025 unsigned long this_load
= this_rq
->load
.weight
;
3028 this_rq
->nr_load_updates
++;
3030 /* Update our load: */
3031 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3032 unsigned long old_load
, new_load
;
3034 /* scale is effectively 1 << i now, and >> i divides by scale */
3036 old_load
= this_rq
->cpu_load
[i
];
3037 new_load
= this_load
;
3039 * Round up the averaging division if load is increasing. This
3040 * prevents us from getting stuck on 9 if the load is 10, for
3043 if (new_load
> old_load
)
3044 new_load
+= scale
-1;
3045 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
3048 if (time_after_eq(jiffies
, this_rq
->calc_load_update
)) {
3049 this_rq
->calc_load_update
+= LOAD_FREQ
;
3050 calc_load_account_active(this_rq
);
3057 * sched_exec - execve() is a valuable balancing opportunity, because at
3058 * this point the task has the smallest effective memory and cache footprint.
3060 void sched_exec(void)
3062 struct task_struct
*p
= current
;
3063 struct migration_req req
;
3064 int dest_cpu
, this_cpu
;
3065 unsigned long flags
;
3069 this_cpu
= get_cpu();
3070 dest_cpu
= select_task_rq(p
, SD_BALANCE_EXEC
, 0);
3071 if (dest_cpu
== this_cpu
) {
3076 rq
= task_rq_lock(p
, &flags
);
3080 * select_task_rq() can race against ->cpus_allowed
3082 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
)
3083 || unlikely(!cpu_active(dest_cpu
))) {
3084 task_rq_unlock(rq
, &flags
);
3088 /* force the process onto the specified CPU */
3089 if (migrate_task(p
, dest_cpu
, &req
)) {
3090 /* Need to wait for migration thread (might exit: take ref). */
3091 struct task_struct
*mt
= rq
->migration_thread
;
3093 get_task_struct(mt
);
3094 task_rq_unlock(rq
, &flags
);
3095 wake_up_process(mt
);
3096 put_task_struct(mt
);
3097 wait_for_completion(&req
.done
);
3101 task_rq_unlock(rq
, &flags
);
3106 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3108 EXPORT_PER_CPU_SYMBOL(kstat
);
3111 * Return any ns on the sched_clock that have not yet been accounted in
3112 * @p in case that task is currently running.
3114 * Called with task_rq_lock() held on @rq.
3116 static u64
do_task_delta_exec(struct task_struct
*p
, struct rq
*rq
)
3120 if (task_current(rq
, p
)) {
3121 update_rq_clock(rq
);
3122 ns
= rq
->clock
- p
->se
.exec_start
;
3130 unsigned long long task_delta_exec(struct task_struct
*p
)
3132 unsigned long flags
;
3136 rq
= task_rq_lock(p
, &flags
);
3137 ns
= do_task_delta_exec(p
, rq
);
3138 task_rq_unlock(rq
, &flags
);
3144 * Return accounted runtime for the task.
3145 * In case the task is currently running, return the runtime plus current's
3146 * pending runtime that have not been accounted yet.
3148 unsigned long long task_sched_runtime(struct task_struct
*p
)
3150 unsigned long flags
;
3154 rq
= task_rq_lock(p
, &flags
);
3155 ns
= p
->se
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3156 task_rq_unlock(rq
, &flags
);
3162 * Return sum_exec_runtime for the thread group.
3163 * In case the task is currently running, return the sum plus current's
3164 * pending runtime that have not been accounted yet.
3166 * Note that the thread group might have other running tasks as well,
3167 * so the return value not includes other pending runtime that other
3168 * running tasks might have.
3170 unsigned long long thread_group_sched_runtime(struct task_struct
*p
)
3172 struct task_cputime totals
;
3173 unsigned long flags
;
3177 rq
= task_rq_lock(p
, &flags
);
3178 thread_group_cputime(p
, &totals
);
3179 ns
= totals
.sum_exec_runtime
+ do_task_delta_exec(p
, rq
);
3180 task_rq_unlock(rq
, &flags
);
3186 * Account user cpu time to a process.
3187 * @p: the process that the cpu time gets accounted to
3188 * @cputime: the cpu time spent in user space since the last update
3189 * @cputime_scaled: cputime scaled by cpu frequency
3191 void account_user_time(struct task_struct
*p
, cputime_t cputime
,
3192 cputime_t cputime_scaled
)
3194 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3197 /* Add user time to process. */
3198 p
->utime
= cputime_add(p
->utime
, cputime
);
3199 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3200 account_group_user_time(p
, cputime
);
3202 /* Add user time to cpustat. */
3203 tmp
= cputime_to_cputime64(cputime
);
3204 if (TASK_NICE(p
) > 0)
3205 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3207 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3209 cpuacct_update_stats(p
, CPUACCT_STAT_USER
, cputime
);
3210 /* Account for user time used */
3211 acct_update_integrals(p
);
3215 * Account guest cpu time to a process.
3216 * @p: the process that the cpu time gets accounted to
3217 * @cputime: the cpu time spent in virtual machine since the last update
3218 * @cputime_scaled: cputime scaled by cpu frequency
3220 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
,
3221 cputime_t cputime_scaled
)
3224 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3226 tmp
= cputime_to_cputime64(cputime
);
3228 /* Add guest time to process. */
3229 p
->utime
= cputime_add(p
->utime
, cputime
);
3230 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime_scaled
);
3231 account_group_user_time(p
, cputime
);
3232 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3234 /* Add guest time to cpustat. */
3235 if (TASK_NICE(p
) > 0) {
3236 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3237 cpustat
->guest_nice
= cputime64_add(cpustat
->guest_nice
, tmp
);
3239 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3240 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3245 * Account system cpu time to a process.
3246 * @p: the process that the cpu time gets accounted to
3247 * @hardirq_offset: the offset to subtract from hardirq_count()
3248 * @cputime: the cpu time spent in kernel space since the last update
3249 * @cputime_scaled: cputime scaled by cpu frequency
3251 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3252 cputime_t cputime
, cputime_t cputime_scaled
)
3254 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3257 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3258 account_guest_time(p
, cputime
, cputime_scaled
);
3262 /* Add system time to process. */
3263 p
->stime
= cputime_add(p
->stime
, cputime
);
3264 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime_scaled
);
3265 account_group_system_time(p
, cputime
);
3267 /* Add system time to cpustat. */
3268 tmp
= cputime_to_cputime64(cputime
);
3269 if (hardirq_count() - hardirq_offset
)
3270 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3271 else if (softirq_count())
3272 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3274 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3276 cpuacct_update_stats(p
, CPUACCT_STAT_SYSTEM
, cputime
);
3278 /* Account for system time used */
3279 acct_update_integrals(p
);
3283 * Account for involuntary wait time.
3284 * @steal: the cpu time spent in involuntary wait
3286 void account_steal_time(cputime_t cputime
)
3288 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3289 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3291 cpustat
->steal
= cputime64_add(cpustat
->steal
, cputime64
);
3295 * Account for idle time.
3296 * @cputime: the cpu time spent in idle wait
3298 void account_idle_time(cputime_t cputime
)
3300 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3301 cputime64_t cputime64
= cputime_to_cputime64(cputime
);
3302 struct rq
*rq
= this_rq();
3304 if (atomic_read(&rq
->nr_iowait
) > 0)
3305 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, cputime64
);
3307 cpustat
->idle
= cputime64_add(cpustat
->idle
, cputime64
);
3310 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
3313 * Account a single tick of cpu time.
3314 * @p: the process that the cpu time gets accounted to
3315 * @user_tick: indicates if the tick is a user or a system tick
3317 void account_process_tick(struct task_struct
*p
, int user_tick
)
3319 cputime_t one_jiffy_scaled
= cputime_to_scaled(cputime_one_jiffy
);
3320 struct rq
*rq
= this_rq();
3323 account_user_time(p
, cputime_one_jiffy
, one_jiffy_scaled
);
3324 else if ((p
!= rq
->idle
) || (irq_count() != HARDIRQ_OFFSET
))
3325 account_system_time(p
, HARDIRQ_OFFSET
, cputime_one_jiffy
,
3328 account_idle_time(cputime_one_jiffy
);
3332 * Account multiple ticks of steal time.
3333 * @p: the process from which the cpu time has been stolen
3334 * @ticks: number of stolen ticks
3336 void account_steal_ticks(unsigned long ticks
)
3338 account_steal_time(jiffies_to_cputime(ticks
));
3342 * Account multiple ticks of idle time.
3343 * @ticks: number of stolen ticks
3345 void account_idle_ticks(unsigned long ticks
)
3347 account_idle_time(jiffies_to_cputime(ticks
));
3353 * Use precise platform statistics if available:
3355 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
3356 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3362 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3364 struct task_cputime cputime
;
3366 thread_group_cputime(p
, &cputime
);
3368 *ut
= cputime
.utime
;
3369 *st
= cputime
.stime
;
3373 #ifndef nsecs_to_cputime
3374 # define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
3377 void task_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3379 cputime_t rtime
, utime
= p
->utime
, total
= cputime_add(utime
, p
->stime
);
3382 * Use CFS's precise accounting:
3384 rtime
= nsecs_to_cputime(p
->se
.sum_exec_runtime
);
3389 temp
= (u64
)(rtime
* utime
);
3390 do_div(temp
, total
);
3391 utime
= (cputime_t
)temp
;
3396 * Compare with previous values, to keep monotonicity:
3398 p
->prev_utime
= max(p
->prev_utime
, utime
);
3399 p
->prev_stime
= max(p
->prev_stime
, cputime_sub(rtime
, p
->prev_utime
));
3401 *ut
= p
->prev_utime
;
3402 *st
= p
->prev_stime
;
3406 * Must be called with siglock held.
3408 void thread_group_times(struct task_struct
*p
, cputime_t
*ut
, cputime_t
*st
)
3410 struct signal_struct
*sig
= p
->signal
;
3411 struct task_cputime cputime
;
3412 cputime_t rtime
, utime
, total
;
3414 thread_group_cputime(p
, &cputime
);
3416 total
= cputime_add(cputime
.utime
, cputime
.stime
);
3417 rtime
= nsecs_to_cputime(cputime
.sum_exec_runtime
);
3422 temp
= (u64
)(rtime
* cputime
.utime
);
3423 do_div(temp
, total
);
3424 utime
= (cputime_t
)temp
;
3428 sig
->prev_utime
= max(sig
->prev_utime
, utime
);
3429 sig
->prev_stime
= max(sig
->prev_stime
,
3430 cputime_sub(rtime
, sig
->prev_utime
));
3432 *ut
= sig
->prev_utime
;
3433 *st
= sig
->prev_stime
;
3438 * This function gets called by the timer code, with HZ frequency.
3439 * We call it with interrupts disabled.
3441 * It also gets called by the fork code, when changing the parent's
3444 void scheduler_tick(void)
3446 int cpu
= smp_processor_id();
3447 struct rq
*rq
= cpu_rq(cpu
);
3448 struct task_struct
*curr
= rq
->curr
;
3452 raw_spin_lock(&rq
->lock
);
3453 update_rq_clock(rq
);
3454 update_cpu_load(rq
);
3455 curr
->sched_class
->task_tick(rq
, curr
, 0);
3456 raw_spin_unlock(&rq
->lock
);
3458 perf_event_task_tick(curr
, cpu
);
3461 rq
->idle_at_tick
= idle_cpu(cpu
);
3462 trigger_load_balance(rq
, cpu
);
3466 notrace
unsigned long get_parent_ip(unsigned long addr
)
3468 if (in_lock_functions(addr
)) {
3469 addr
= CALLER_ADDR2
;
3470 if (in_lock_functions(addr
))
3471 addr
= CALLER_ADDR3
;
3476 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
3477 defined(CONFIG_PREEMPT_TRACER))
3479 void __kprobes
add_preempt_count(int val
)
3481 #ifdef CONFIG_DEBUG_PREEMPT
3485 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3488 preempt_count() += val
;
3489 #ifdef CONFIG_DEBUG_PREEMPT
3491 * Spinlock count overflowing soon?
3493 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
3496 if (preempt_count() == val
)
3497 trace_preempt_off(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3499 EXPORT_SYMBOL(add_preempt_count
);
3501 void __kprobes
sub_preempt_count(int val
)
3503 #ifdef CONFIG_DEBUG_PREEMPT
3507 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
3510 * Is the spinlock portion underflowing?
3512 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
3513 !(preempt_count() & PREEMPT_MASK
)))
3517 if (preempt_count() == val
)
3518 trace_preempt_on(CALLER_ADDR0
, get_parent_ip(CALLER_ADDR1
));
3519 preempt_count() -= val
;
3521 EXPORT_SYMBOL(sub_preempt_count
);
3526 * Print scheduling while atomic bug:
3528 static noinline
void __schedule_bug(struct task_struct
*prev
)
3530 struct pt_regs
*regs
= get_irq_regs();
3532 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
3533 prev
->comm
, prev
->pid
, preempt_count());
3535 debug_show_held_locks(prev
);
3537 if (irqs_disabled())
3538 print_irqtrace_events(prev
);
3547 * Various schedule()-time debugging checks and statistics:
3549 static inline void schedule_debug(struct task_struct
*prev
)
3552 * Test if we are atomic. Since do_exit() needs to call into
3553 * schedule() atomically, we ignore that path for now.
3554 * Otherwise, whine if we are scheduling when we should not be.
3556 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
3557 __schedule_bug(prev
);
3559 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
3561 schedstat_inc(this_rq(), sched_count
);
3562 #ifdef CONFIG_SCHEDSTATS
3563 if (unlikely(prev
->lock_depth
>= 0)) {
3564 schedstat_inc(this_rq(), bkl_count
);
3565 schedstat_inc(prev
, sched_info
.bkl_count
);
3570 static void put_prev_task(struct rq
*rq
, struct task_struct
*prev
)
3572 if (prev
->state
== TASK_RUNNING
) {
3573 u64 runtime
= prev
->se
.sum_exec_runtime
;
3575 runtime
-= prev
->se
.prev_sum_exec_runtime
;
3576 runtime
= min_t(u64
, runtime
, 2*sysctl_sched_migration_cost
);
3579 * In order to avoid avg_overlap growing stale when we are
3580 * indeed overlapping and hence not getting put to sleep, grow
3581 * the avg_overlap on preemption.
3583 * We use the average preemption runtime because that
3584 * correlates to the amount of cache footprint a task can
3587 update_avg(&prev
->se
.avg_overlap
, runtime
);
3589 prev
->sched_class
->put_prev_task(rq
, prev
);
3593 * Pick up the highest-prio task:
3595 static inline struct task_struct
*
3596 pick_next_task(struct rq
*rq
)
3598 const struct sched_class
*class;
3599 struct task_struct
*p
;
3602 * Optimization: we know that if all tasks are in
3603 * the fair class we can call that function directly:
3605 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
3606 p
= fair_sched_class
.pick_next_task(rq
);
3611 class = sched_class_highest
;
3613 p
= class->pick_next_task(rq
);
3617 * Will never be NULL as the idle class always
3618 * returns a non-NULL p:
3620 class = class->next
;
3625 * schedule() is the main scheduler function.
3627 asmlinkage
void __sched
schedule(void)
3629 struct task_struct
*prev
, *next
;
3630 unsigned long *switch_count
;
3636 cpu
= smp_processor_id();
3640 switch_count
= &prev
->nivcsw
;
3642 release_kernel_lock(prev
);
3643 need_resched_nonpreemptible
:
3645 schedule_debug(prev
);
3647 if (sched_feat(HRTICK
))
3650 raw_spin_lock_irq(&rq
->lock
);
3651 update_rq_clock(rq
);
3652 clear_tsk_need_resched(prev
);
3654 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
3655 if (unlikely(signal_pending_state(prev
->state
, prev
)))
3656 prev
->state
= TASK_RUNNING
;
3658 deactivate_task(rq
, prev
, 1);
3659 switch_count
= &prev
->nvcsw
;
3662 pre_schedule(rq
, prev
);
3664 if (unlikely(!rq
->nr_running
))
3665 idle_balance(cpu
, rq
);
3667 put_prev_task(rq
, prev
);
3668 next
= pick_next_task(rq
);
3670 if (likely(prev
!= next
)) {
3671 sched_info_switch(prev
, next
);
3672 perf_event_task_sched_out(prev
, next
, cpu
);
3678 context_switch(rq
, prev
, next
); /* unlocks the rq */
3680 * the context switch might have flipped the stack from under
3681 * us, hence refresh the local variables.
3683 cpu
= smp_processor_id();
3686 raw_spin_unlock_irq(&rq
->lock
);
3690 if (unlikely(reacquire_kernel_lock(current
) < 0))
3691 goto need_resched_nonpreemptible
;
3693 preempt_enable_no_resched();
3697 EXPORT_SYMBOL(schedule
);
3699 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
3701 * Look out! "owner" is an entirely speculative pointer
3702 * access and not reliable.
3704 int mutex_spin_on_owner(struct mutex
*lock
, struct thread_info
*owner
)
3709 if (!sched_feat(OWNER_SPIN
))
3712 #ifdef CONFIG_DEBUG_PAGEALLOC
3714 * Need to access the cpu field knowing that
3715 * DEBUG_PAGEALLOC could have unmapped it if
3716 * the mutex owner just released it and exited.
3718 if (probe_kernel_address(&owner
->cpu
, cpu
))
3725 * Even if the access succeeded (likely case),
3726 * the cpu field may no longer be valid.
3728 if (cpu
>= nr_cpumask_bits
)
3732 * We need to validate that we can do a
3733 * get_cpu() and that we have the percpu area.
3735 if (!cpu_online(cpu
))
3742 * Owner changed, break to re-assess state.
3744 if (lock
->owner
!= owner
)
3748 * Is that owner really running on that cpu?
3750 if (task_thread_info(rq
->curr
) != owner
|| need_resched())
3760 #ifdef CONFIG_PREEMPT
3762 * this is the entry point to schedule() from in-kernel preemption
3763 * off of preempt_enable. Kernel preemptions off return from interrupt
3764 * occur there and call schedule directly.
3766 asmlinkage
void __sched
preempt_schedule(void)
3768 struct thread_info
*ti
= current_thread_info();
3771 * If there is a non-zero preempt_count or interrupts are disabled,
3772 * we do not want to preempt the current task. Just return..
3774 if (likely(ti
->preempt_count
|| irqs_disabled()))
3778 add_preempt_count(PREEMPT_ACTIVE
);
3780 sub_preempt_count(PREEMPT_ACTIVE
);
3783 * Check again in case we missed a preemption opportunity
3784 * between schedule and now.
3787 } while (need_resched());
3789 EXPORT_SYMBOL(preempt_schedule
);
3792 * this is the entry point to schedule() from kernel preemption
3793 * off of irq context.
3794 * Note, that this is called and return with irqs disabled. This will
3795 * protect us against recursive calling from irq.
3797 asmlinkage
void __sched
preempt_schedule_irq(void)
3799 struct thread_info
*ti
= current_thread_info();
3801 /* Catch callers which need to be fixed */
3802 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
3805 add_preempt_count(PREEMPT_ACTIVE
);
3808 local_irq_disable();
3809 sub_preempt_count(PREEMPT_ACTIVE
);
3812 * Check again in case we missed a preemption opportunity
3813 * between schedule and now.
3816 } while (need_resched());
3819 #endif /* CONFIG_PREEMPT */
3821 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int wake_flags
,
3824 return try_to_wake_up(curr
->private, mode
, wake_flags
);
3826 EXPORT_SYMBOL(default_wake_function
);
3829 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3830 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3831 * number) then we wake all the non-exclusive tasks and one exclusive task.
3833 * There are circumstances in which we can try to wake a task which has already
3834 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3835 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3837 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
3838 int nr_exclusive
, int wake_flags
, void *key
)
3840 wait_queue_t
*curr
, *next
;
3842 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
3843 unsigned flags
= curr
->flags
;
3845 if (curr
->func(curr
, mode
, wake_flags
, key
) &&
3846 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
3852 * __wake_up - wake up threads blocked on a waitqueue.
3854 * @mode: which threads
3855 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3856 * @key: is directly passed to the wakeup function
3858 * It may be assumed that this function implies a write memory barrier before
3859 * changing the task state if and only if any tasks are woken up.
3861 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
3862 int nr_exclusive
, void *key
)
3864 unsigned long flags
;
3866 spin_lock_irqsave(&q
->lock
, flags
);
3867 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
3868 spin_unlock_irqrestore(&q
->lock
, flags
);
3870 EXPORT_SYMBOL(__wake_up
);
3873 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3875 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
3877 __wake_up_common(q
, mode
, 1, 0, NULL
);
3880 void __wake_up_locked_key(wait_queue_head_t
*q
, unsigned int mode
, void *key
)
3882 __wake_up_common(q
, mode
, 1, 0, key
);
3886 * __wake_up_sync_key - wake up threads blocked on a waitqueue.
3888 * @mode: which threads
3889 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3890 * @key: opaque value to be passed to wakeup targets
3892 * The sync wakeup differs that the waker knows that it will schedule
3893 * away soon, so while the target thread will be woken up, it will not
3894 * be migrated to another CPU - ie. the two threads are 'synchronized'
3895 * with each other. This can prevent needless bouncing between CPUs.
3897 * On UP it can prevent extra preemption.
3899 * It may be assumed that this function implies a write memory barrier before
3900 * changing the task state if and only if any tasks are woken up.
3902 void __wake_up_sync_key(wait_queue_head_t
*q
, unsigned int mode
,
3903 int nr_exclusive
, void *key
)
3905 unsigned long flags
;
3906 int wake_flags
= WF_SYNC
;
3911 if (unlikely(!nr_exclusive
))
3914 spin_lock_irqsave(&q
->lock
, flags
);
3915 __wake_up_common(q
, mode
, nr_exclusive
, wake_flags
, key
);
3916 spin_unlock_irqrestore(&q
->lock
, flags
);
3918 EXPORT_SYMBOL_GPL(__wake_up_sync_key
);
3921 * __wake_up_sync - see __wake_up_sync_key()
3923 void __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
3925 __wake_up_sync_key(q
, mode
, nr_exclusive
, NULL
);
3927 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
3930 * complete: - signals a single thread waiting on this completion
3931 * @x: holds the state of this particular completion
3933 * This will wake up a single thread waiting on this completion. Threads will be
3934 * awakened in the same order in which they were queued.
3936 * See also complete_all(), wait_for_completion() and related routines.
3938 * It may be assumed that this function implies a write memory barrier before
3939 * changing the task state if and only if any tasks are woken up.
3941 void complete(struct completion
*x
)
3943 unsigned long flags
;
3945 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3947 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
3948 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3950 EXPORT_SYMBOL(complete
);
3953 * complete_all: - signals all threads waiting on this completion
3954 * @x: holds the state of this particular completion
3956 * This will wake up all threads waiting on this particular completion event.
3958 * It may be assumed that this function implies a write memory barrier before
3959 * changing the task state if and only if any tasks are woken up.
3961 void complete_all(struct completion
*x
)
3963 unsigned long flags
;
3965 spin_lock_irqsave(&x
->wait
.lock
, flags
);
3966 x
->done
+= UINT_MAX
/2;
3967 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
3968 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
3970 EXPORT_SYMBOL(complete_all
);
3972 static inline long __sched
3973 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
3976 DECLARE_WAITQUEUE(wait
, current
);
3978 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
3979 __add_wait_queue_tail(&x
->wait
, &wait
);
3981 if (signal_pending_state(state
, current
)) {
3982 timeout
= -ERESTARTSYS
;
3985 __set_current_state(state
);
3986 spin_unlock_irq(&x
->wait
.lock
);
3987 timeout
= schedule_timeout(timeout
);
3988 spin_lock_irq(&x
->wait
.lock
);
3989 } while (!x
->done
&& timeout
);
3990 __remove_wait_queue(&x
->wait
, &wait
);
3995 return timeout
?: 1;
3999 wait_for_common(struct completion
*x
, long timeout
, int state
)
4003 spin_lock_irq(&x
->wait
.lock
);
4004 timeout
= do_wait_for_common(x
, timeout
, state
);
4005 spin_unlock_irq(&x
->wait
.lock
);
4010 * wait_for_completion: - waits for completion of a task
4011 * @x: holds the state of this particular completion
4013 * This waits to be signaled for completion of a specific task. It is NOT
4014 * interruptible and there is no timeout.
4016 * See also similar routines (i.e. wait_for_completion_timeout()) with timeout
4017 * and interrupt capability. Also see complete().
4019 void __sched
wait_for_completion(struct completion
*x
)
4021 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4023 EXPORT_SYMBOL(wait_for_completion
);
4026 * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
4027 * @x: holds the state of this particular completion
4028 * @timeout: timeout value in jiffies
4030 * This waits for either a completion of a specific task to be signaled or for a
4031 * specified timeout to expire. The timeout is in jiffies. It is not
4034 unsigned long __sched
4035 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4037 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4039 EXPORT_SYMBOL(wait_for_completion_timeout
);
4042 * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
4043 * @x: holds the state of this particular completion
4045 * This waits for completion of a specific task to be signaled. It is
4048 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4050 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4051 if (t
== -ERESTARTSYS
)
4055 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4058 * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
4059 * @x: holds the state of this particular completion
4060 * @timeout: timeout value in jiffies
4062 * This waits for either a completion of a specific task to be signaled or for a
4063 * specified timeout to expire. It is interruptible. The timeout is in jiffies.
4065 unsigned long __sched
4066 wait_for_completion_interruptible_timeout(struct completion
*x
,
4067 unsigned long timeout
)
4069 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4071 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4074 * wait_for_completion_killable: - waits for completion of a task (killable)
4075 * @x: holds the state of this particular completion
4077 * This waits to be signaled for completion of a specific task. It can be
4078 * interrupted by a kill signal.
4080 int __sched
wait_for_completion_killable(struct completion
*x
)
4082 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4083 if (t
== -ERESTARTSYS
)
4087 EXPORT_SYMBOL(wait_for_completion_killable
);
4090 * try_wait_for_completion - try to decrement a completion without blocking
4091 * @x: completion structure
4093 * Returns: 0 if a decrement cannot be done without blocking
4094 * 1 if a decrement succeeded.
4096 * If a completion is being used as a counting completion,
4097 * attempt to decrement the counter without blocking. This
4098 * enables us to avoid waiting if the resource the completion
4099 * is protecting is not available.
4101 bool try_wait_for_completion(struct completion
*x
)
4103 unsigned long flags
;
4106 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4111 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4114 EXPORT_SYMBOL(try_wait_for_completion
);
4117 * completion_done - Test to see if a completion has any waiters
4118 * @x: completion structure
4120 * Returns: 0 if there are waiters (wait_for_completion() in progress)
4121 * 1 if there are no waiters.
4124 bool completion_done(struct completion
*x
)
4126 unsigned long flags
;
4129 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4132 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4135 EXPORT_SYMBOL(completion_done
);
4138 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4140 unsigned long flags
;
4143 init_waitqueue_entry(&wait
, current
);
4145 __set_current_state(state
);
4147 spin_lock_irqsave(&q
->lock
, flags
);
4148 __add_wait_queue(q
, &wait
);
4149 spin_unlock(&q
->lock
);
4150 timeout
= schedule_timeout(timeout
);
4151 spin_lock_irq(&q
->lock
);
4152 __remove_wait_queue(q
, &wait
);
4153 spin_unlock_irqrestore(&q
->lock
, flags
);
4158 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4160 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4162 EXPORT_SYMBOL(interruptible_sleep_on
);
4165 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4167 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4169 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4171 void __sched
sleep_on(wait_queue_head_t
*q
)
4173 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4175 EXPORT_SYMBOL(sleep_on
);
4177 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4179 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4181 EXPORT_SYMBOL(sleep_on_timeout
);
4183 #ifdef CONFIG_RT_MUTEXES
4186 * rt_mutex_setprio - set the current priority of a task
4188 * @prio: prio value (kernel-internal form)
4190 * This function changes the 'effective' priority of a task. It does
4191 * not touch ->normal_prio like __setscheduler().
4193 * Used by the rt_mutex code to implement priority inheritance logic.
4195 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4197 unsigned long flags
;
4198 int oldprio
, on_rq
, running
;
4200 const struct sched_class
*prev_class
= p
->sched_class
;
4202 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4204 rq
= task_rq_lock(p
, &flags
);
4205 update_rq_clock(rq
);
4208 on_rq
= p
->se
.on_rq
;
4209 running
= task_current(rq
, p
);
4211 dequeue_task(rq
, p
, 0);
4213 p
->sched_class
->put_prev_task(rq
, p
);
4216 p
->sched_class
= &rt_sched_class
;
4218 p
->sched_class
= &fair_sched_class
;
4223 p
->sched_class
->set_curr_task(rq
);
4225 enqueue_task(rq
, p
, 0, oldprio
< prio
);
4227 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4229 task_rq_unlock(rq
, &flags
);
4234 void set_user_nice(struct task_struct
*p
, long nice
)
4236 int old_prio
, delta
, on_rq
;
4237 unsigned long flags
;
4240 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4243 * We have to be careful, if called from sys_setpriority(),
4244 * the task might be in the middle of scheduling on another CPU.
4246 rq
= task_rq_lock(p
, &flags
);
4247 update_rq_clock(rq
);
4249 * The RT priorities are set via sched_setscheduler(), but we still
4250 * allow the 'normal' nice value to be set - but as expected
4251 * it wont have any effect on scheduling until the task is
4252 * SCHED_FIFO/SCHED_RR:
4254 if (task_has_rt_policy(p
)) {
4255 p
->static_prio
= NICE_TO_PRIO(nice
);
4258 on_rq
= p
->se
.on_rq
;
4260 dequeue_task(rq
, p
, 0);
4262 p
->static_prio
= NICE_TO_PRIO(nice
);
4265 p
->prio
= effective_prio(p
);
4266 delta
= p
->prio
- old_prio
;
4269 enqueue_task(rq
, p
, 0, false);
4271 * If the task increased its priority or is running and
4272 * lowered its priority, then reschedule its CPU:
4274 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4275 resched_task(rq
->curr
);
4278 task_rq_unlock(rq
, &flags
);
4280 EXPORT_SYMBOL(set_user_nice
);
4283 * can_nice - check if a task can reduce its nice value
4287 int can_nice(const struct task_struct
*p
, const int nice
)
4289 /* convert nice value [19,-20] to rlimit style value [1,40] */
4290 int nice_rlim
= 20 - nice
;
4292 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
4293 capable(CAP_SYS_NICE
));
4296 #ifdef __ARCH_WANT_SYS_NICE
4299 * sys_nice - change the priority of the current process.
4300 * @increment: priority increment
4302 * sys_setpriority is a more generic, but much slower function that
4303 * does similar things.
4305 SYSCALL_DEFINE1(nice
, int, increment
)
4310 * Setpriority might change our priority at the same moment.
4311 * We don't have to worry. Conceptually one call occurs first
4312 * and we have a single winner.
4314 if (increment
< -40)
4319 nice
= TASK_NICE(current
) + increment
;
4325 if (increment
< 0 && !can_nice(current
, nice
))
4328 retval
= security_task_setnice(current
, nice
);
4332 set_user_nice(current
, nice
);
4339 * task_prio - return the priority value of a given task.
4340 * @p: the task in question.
4342 * This is the priority value as seen by users in /proc.
4343 * RT tasks are offset by -200. Normal tasks are centered
4344 * around 0, value goes from -16 to +15.
4346 int task_prio(const struct task_struct
*p
)
4348 return p
->prio
- MAX_RT_PRIO
;
4352 * task_nice - return the nice value of a given task.
4353 * @p: the task in question.
4355 int task_nice(const struct task_struct
*p
)
4357 return TASK_NICE(p
);
4359 EXPORT_SYMBOL(task_nice
);
4362 * idle_cpu - is a given cpu idle currently?
4363 * @cpu: the processor in question.
4365 int idle_cpu(int cpu
)
4367 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4371 * idle_task - return the idle task for a given cpu.
4372 * @cpu: the processor in question.
4374 struct task_struct
*idle_task(int cpu
)
4376 return cpu_rq(cpu
)->idle
;
4380 * find_process_by_pid - find a process with a matching PID value.
4381 * @pid: the pid in question.
4383 static struct task_struct
*find_process_by_pid(pid_t pid
)
4385 return pid
? find_task_by_vpid(pid
) : current
;
4388 /* Actually do priority change: must hold rq lock. */
4390 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4392 BUG_ON(p
->se
.on_rq
);
4395 p
->rt_priority
= prio
;
4396 p
->normal_prio
= normal_prio(p
);
4397 /* we are holding p->pi_lock already */
4398 p
->prio
= rt_mutex_getprio(p
);
4399 if (rt_prio(p
->prio
))
4400 p
->sched_class
= &rt_sched_class
;
4402 p
->sched_class
= &fair_sched_class
;
4407 * check the target process has a UID that matches the current process's
4409 static bool check_same_owner(struct task_struct
*p
)
4411 const struct cred
*cred
= current_cred(), *pcred
;
4415 pcred
= __task_cred(p
);
4416 match
= (cred
->euid
== pcred
->euid
||
4417 cred
->euid
== pcred
->uid
);
4422 static int __sched_setscheduler(struct task_struct
*p
, int policy
,
4423 struct sched_param
*param
, bool user
)
4425 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4426 unsigned long flags
;
4427 const struct sched_class
*prev_class
= p
->sched_class
;
4431 /* may grab non-irq protected spin_locks */
4432 BUG_ON(in_interrupt());
4434 /* double check policy once rq lock held */
4436 reset_on_fork
= p
->sched_reset_on_fork
;
4437 policy
= oldpolicy
= p
->policy
;
4439 reset_on_fork
= !!(policy
& SCHED_RESET_ON_FORK
);
4440 policy
&= ~SCHED_RESET_ON_FORK
;
4442 if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4443 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4444 policy
!= SCHED_IDLE
)
4449 * Valid priorities for SCHED_FIFO and SCHED_RR are
4450 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4451 * SCHED_BATCH and SCHED_IDLE is 0.
4453 if (param
->sched_priority
< 0 ||
4454 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4455 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4457 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4461 * Allow unprivileged RT tasks to decrease priority:
4463 if (user
&& !capable(CAP_SYS_NICE
)) {
4464 if (rt_policy(policy
)) {
4465 unsigned long rlim_rtprio
;
4467 if (!lock_task_sighand(p
, &flags
))
4469 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
4470 unlock_task_sighand(p
, &flags
);
4472 /* can't set/change the rt policy */
4473 if (policy
!= p
->policy
&& !rlim_rtprio
)
4476 /* can't increase priority */
4477 if (param
->sched_priority
> p
->rt_priority
&&
4478 param
->sched_priority
> rlim_rtprio
)
4482 * Like positive nice levels, dont allow tasks to
4483 * move out of SCHED_IDLE either:
4485 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4488 /* can't change other user's priorities */
4489 if (!check_same_owner(p
))
4492 /* Normal users shall not reset the sched_reset_on_fork flag */
4493 if (p
->sched_reset_on_fork
&& !reset_on_fork
)
4498 #ifdef CONFIG_RT_GROUP_SCHED
4500 * Do not allow realtime tasks into groups that have no runtime
4503 if (rt_bandwidth_enabled() && rt_policy(policy
) &&
4504 task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
4508 retval
= security_task_setscheduler(p
, policy
, param
);
4514 * make sure no PI-waiters arrive (or leave) while we are
4515 * changing the priority of the task:
4517 raw_spin_lock_irqsave(&p
->pi_lock
, flags
);
4519 * To be able to change p->policy safely, the apropriate
4520 * runqueue lock must be held.
4522 rq
= __task_rq_lock(p
);
4523 /* recheck policy now with rq lock held */
4524 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4525 policy
= oldpolicy
= -1;
4526 __task_rq_unlock(rq
);
4527 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4530 update_rq_clock(rq
);
4531 on_rq
= p
->se
.on_rq
;
4532 running
= task_current(rq
, p
);
4534 deactivate_task(rq
, p
, 0);
4536 p
->sched_class
->put_prev_task(rq
, p
);
4538 p
->sched_reset_on_fork
= reset_on_fork
;
4541 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4544 p
->sched_class
->set_curr_task(rq
);
4546 activate_task(rq
, p
, 0);
4548 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4550 __task_rq_unlock(rq
);
4551 raw_spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4553 rt_mutex_adjust_pi(p
);
4559 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4560 * @p: the task in question.
4561 * @policy: new policy.
4562 * @param: structure containing the new RT priority.
4564 * NOTE that the task may be already dead.
4566 int sched_setscheduler(struct task_struct
*p
, int policy
,
4567 struct sched_param
*param
)
4569 return __sched_setscheduler(p
, policy
, param
, true);
4571 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4574 * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
4575 * @p: the task in question.
4576 * @policy: new policy.
4577 * @param: structure containing the new RT priority.
4579 * Just like sched_setscheduler, only don't bother checking if the
4580 * current context has permission. For example, this is needed in
4581 * stop_machine(): we create temporary high priority worker threads,
4582 * but our caller might not have that capability.
4584 int sched_setscheduler_nocheck(struct task_struct
*p
, int policy
,
4585 struct sched_param
*param
)
4587 return __sched_setscheduler(p
, policy
, param
, false);
4591 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4593 struct sched_param lparam
;
4594 struct task_struct
*p
;
4597 if (!param
|| pid
< 0)
4599 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4604 p
= find_process_by_pid(pid
);
4606 retval
= sched_setscheduler(p
, policy
, &lparam
);
4613 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4614 * @pid: the pid in question.
4615 * @policy: new policy.
4616 * @param: structure containing the new RT priority.
4618 SYSCALL_DEFINE3(sched_setscheduler
, pid_t
, pid
, int, policy
,
4619 struct sched_param __user
*, param
)
4621 /* negative values for policy are not valid */
4625 return do_sched_setscheduler(pid
, policy
, param
);
4629 * sys_sched_setparam - set/change the RT priority of a thread
4630 * @pid: the pid in question.
4631 * @param: structure containing the new RT priority.
4633 SYSCALL_DEFINE2(sched_setparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4635 return do_sched_setscheduler(pid
, -1, param
);
4639 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4640 * @pid: the pid in question.
4642 SYSCALL_DEFINE1(sched_getscheduler
, pid_t
, pid
)
4644 struct task_struct
*p
;
4652 p
= find_process_by_pid(pid
);
4654 retval
= security_task_getscheduler(p
);
4657 | (p
->sched_reset_on_fork
? SCHED_RESET_ON_FORK
: 0);
4664 * sys_sched_getparam - get the RT priority of a thread
4665 * @pid: the pid in question.
4666 * @param: structure containing the RT priority.
4668 SYSCALL_DEFINE2(sched_getparam
, pid_t
, pid
, struct sched_param __user
*, param
)
4670 struct sched_param lp
;
4671 struct task_struct
*p
;
4674 if (!param
|| pid
< 0)
4678 p
= find_process_by_pid(pid
);
4683 retval
= security_task_getscheduler(p
);
4687 lp
.sched_priority
= p
->rt_priority
;
4691 * This one might sleep, we cannot do it with a spinlock held ...
4693 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4702 long sched_setaffinity(pid_t pid
, const struct cpumask
*in_mask
)
4704 cpumask_var_t cpus_allowed
, new_mask
;
4705 struct task_struct
*p
;
4711 p
= find_process_by_pid(pid
);
4718 /* Prevent p going away */
4722 if (!alloc_cpumask_var(&cpus_allowed
, GFP_KERNEL
)) {
4726 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
)) {
4728 goto out_free_cpus_allowed
;
4731 if (!check_same_owner(p
) && !capable(CAP_SYS_NICE
))
4734 retval
= security_task_setscheduler(p
, 0, NULL
);
4738 cpuset_cpus_allowed(p
, cpus_allowed
);
4739 cpumask_and(new_mask
, in_mask
, cpus_allowed
);
4741 retval
= set_cpus_allowed_ptr(p
, new_mask
);
4744 cpuset_cpus_allowed(p
, cpus_allowed
);
4745 if (!cpumask_subset(new_mask
, cpus_allowed
)) {
4747 * We must have raced with a concurrent cpuset
4748 * update. Just reset the cpus_allowed to the
4749 * cpuset's cpus_allowed
4751 cpumask_copy(new_mask
, cpus_allowed
);
4756 free_cpumask_var(new_mask
);
4757 out_free_cpus_allowed
:
4758 free_cpumask_var(cpus_allowed
);
4765 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
4766 struct cpumask
*new_mask
)
4768 if (len
< cpumask_size())
4769 cpumask_clear(new_mask
);
4770 else if (len
> cpumask_size())
4771 len
= cpumask_size();
4773 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
4777 * sys_sched_setaffinity - set the cpu affinity of a process
4778 * @pid: pid of the process
4779 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4780 * @user_mask_ptr: user-space pointer to the new cpu mask
4782 SYSCALL_DEFINE3(sched_setaffinity
, pid_t
, pid
, unsigned int, len
,
4783 unsigned long __user
*, user_mask_ptr
)
4785 cpumask_var_t new_mask
;
4788 if (!alloc_cpumask_var(&new_mask
, GFP_KERNEL
))
4791 retval
= get_user_cpu_mask(user_mask_ptr
, len
, new_mask
);
4793 retval
= sched_setaffinity(pid
, new_mask
);
4794 free_cpumask_var(new_mask
);
4798 long sched_getaffinity(pid_t pid
, struct cpumask
*mask
)
4800 struct task_struct
*p
;
4801 unsigned long flags
;
4809 p
= find_process_by_pid(pid
);
4813 retval
= security_task_getscheduler(p
);
4817 rq
= task_rq_lock(p
, &flags
);
4818 cpumask_and(mask
, &p
->cpus_allowed
, cpu_online_mask
);
4819 task_rq_unlock(rq
, &flags
);
4829 * sys_sched_getaffinity - get the cpu affinity of a process
4830 * @pid: pid of the process
4831 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4832 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4834 SYSCALL_DEFINE3(sched_getaffinity
, pid_t
, pid
, unsigned int, len
,
4835 unsigned long __user
*, user_mask_ptr
)
4840 if (len
< cpumask_size())
4843 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
4846 ret
= sched_getaffinity(pid
, mask
);
4848 if (copy_to_user(user_mask_ptr
, mask
, cpumask_size()))
4851 ret
= cpumask_size();
4853 free_cpumask_var(mask
);
4859 * sys_sched_yield - yield the current processor to other threads.
4861 * This function yields the current CPU to other tasks. If there are no
4862 * other threads running on this CPU then this function will return.
4864 SYSCALL_DEFINE0(sched_yield
)
4866 struct rq
*rq
= this_rq_lock();
4868 schedstat_inc(rq
, yld_count
);
4869 current
->sched_class
->yield_task(rq
);
4872 * Since we are going to call schedule() anyway, there's
4873 * no need to preempt or enable interrupts:
4875 __release(rq
->lock
);
4876 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
4877 do_raw_spin_unlock(&rq
->lock
);
4878 preempt_enable_no_resched();
4885 static inline int should_resched(void)
4887 return need_resched() && !(preempt_count() & PREEMPT_ACTIVE
);
4890 static void __cond_resched(void)
4892 add_preempt_count(PREEMPT_ACTIVE
);
4894 sub_preempt_count(PREEMPT_ACTIVE
);
4897 int __sched
_cond_resched(void)
4899 if (should_resched()) {
4905 EXPORT_SYMBOL(_cond_resched
);
4908 * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
4909 * call schedule, and on return reacquire the lock.
4911 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4912 * operations here to prevent schedule() from being called twice (once via
4913 * spin_unlock(), once by hand).
4915 int __cond_resched_lock(spinlock_t
*lock
)
4917 int resched
= should_resched();
4920 lockdep_assert_held(lock
);
4922 if (spin_needbreak(lock
) || resched
) {
4933 EXPORT_SYMBOL(__cond_resched_lock
);
4935 int __sched
__cond_resched_softirq(void)
4937 BUG_ON(!in_softirq());
4939 if (should_resched()) {
4947 EXPORT_SYMBOL(__cond_resched_softirq
);
4950 * yield - yield the current processor to other threads.
4952 * This is a shortcut for kernel-space yielding - it marks the
4953 * thread runnable and calls sys_sched_yield().
4955 void __sched
yield(void)
4957 set_current_state(TASK_RUNNING
);
4960 EXPORT_SYMBOL(yield
);
4963 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4964 * that process accounting knows that this is a task in IO wait state.
4966 void __sched
io_schedule(void)
4968 struct rq
*rq
= raw_rq();
4970 delayacct_blkio_start();
4971 atomic_inc(&rq
->nr_iowait
);
4972 current
->in_iowait
= 1;
4974 current
->in_iowait
= 0;
4975 atomic_dec(&rq
->nr_iowait
);
4976 delayacct_blkio_end();
4978 EXPORT_SYMBOL(io_schedule
);
4980 long __sched
io_schedule_timeout(long timeout
)
4982 struct rq
*rq
= raw_rq();
4985 delayacct_blkio_start();
4986 atomic_inc(&rq
->nr_iowait
);
4987 current
->in_iowait
= 1;
4988 ret
= schedule_timeout(timeout
);
4989 current
->in_iowait
= 0;
4990 atomic_dec(&rq
->nr_iowait
);
4991 delayacct_blkio_end();
4996 * sys_sched_get_priority_max - return maximum RT priority.
4997 * @policy: scheduling class.
4999 * this syscall returns the maximum rt_priority that can be used
5000 * by a given scheduling class.
5002 SYSCALL_DEFINE1(sched_get_priority_max
, int, policy
)
5009 ret
= MAX_USER_RT_PRIO
-1;
5021 * sys_sched_get_priority_min - return minimum RT priority.
5022 * @policy: scheduling class.
5024 * this syscall returns the minimum rt_priority that can be used
5025 * by a given scheduling class.
5027 SYSCALL_DEFINE1(sched_get_priority_min
, int, policy
)
5045 * sys_sched_rr_get_interval - return the default timeslice of a process.
5046 * @pid: pid of the process.
5047 * @interval: userspace pointer to the timeslice value.
5049 * this syscall writes the default timeslice value of a given process
5050 * into the user-space timespec buffer. A value of '0' means infinity.
5052 SYSCALL_DEFINE2(sched_rr_get_interval
, pid_t
, pid
,
5053 struct timespec __user
*, interval
)
5055 struct task_struct
*p
;
5056 unsigned int time_slice
;
5057 unsigned long flags
;
5067 p
= find_process_by_pid(pid
);
5071 retval
= security_task_getscheduler(p
);
5075 rq
= task_rq_lock(p
, &flags
);
5076 time_slice
= p
->sched_class
->get_rr_interval(rq
, p
);
5077 task_rq_unlock(rq
, &flags
);
5080 jiffies_to_timespec(time_slice
, &t
);
5081 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5089 static const char stat_nam
[] = TASK_STATE_TO_CHAR_STR
;
5091 void sched_show_task(struct task_struct
*p
)
5093 unsigned long free
= 0;
5096 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5097 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5098 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5099 #if BITS_PER_LONG == 32
5100 if (state
== TASK_RUNNING
)
5101 printk(KERN_CONT
" running ");
5103 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5105 if (state
== TASK_RUNNING
)
5106 printk(KERN_CONT
" running task ");
5108 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5110 #ifdef CONFIG_DEBUG_STACK_USAGE
5111 free
= stack_not_used(p
);
5113 printk(KERN_CONT
"%5lu %5d %6d 0x%08lx\n", free
,
5114 task_pid_nr(p
), task_pid_nr(p
->real_parent
),
5115 (unsigned long)task_thread_info(p
)->flags
);
5117 show_stack(p
, NULL
);
5120 void show_state_filter(unsigned long state_filter
)
5122 struct task_struct
*g
, *p
;
5124 #if BITS_PER_LONG == 32
5126 " task PC stack pid father\n");
5129 " task PC stack pid father\n");
5131 read_lock(&tasklist_lock
);
5132 do_each_thread(g
, p
) {
5134 * reset the NMI-timeout, listing all files on a slow
5135 * console might take alot of time:
5137 touch_nmi_watchdog();
5138 if (!state_filter
|| (p
->state
& state_filter
))
5140 } while_each_thread(g
, p
);
5142 touch_all_softlockup_watchdogs();
5144 #ifdef CONFIG_SCHED_DEBUG
5145 sysrq_sched_debug_show();
5147 read_unlock(&tasklist_lock
);
5149 * Only show locks if all tasks are dumped:
5152 debug_show_all_locks();
5155 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5157 idle
->sched_class
= &idle_sched_class
;
5161 * init_idle - set up an idle thread for a given CPU
5162 * @idle: task in question
5163 * @cpu: cpu the idle task belongs to
5165 * NOTE: this function does not set the idle thread's NEED_RESCHED
5166 * flag, to make booting more robust.
5168 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5170 struct rq
*rq
= cpu_rq(cpu
);
5171 unsigned long flags
;
5173 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5176 idle
->state
= TASK_RUNNING
;
5177 idle
->se
.exec_start
= sched_clock();
5179 cpumask_copy(&idle
->cpus_allowed
, cpumask_of(cpu
));
5180 __set_task_cpu(idle
, cpu
);
5182 rq
->curr
= rq
->idle
= idle
;
5183 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5186 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5188 /* Set the preempt count _outside_ the spinlocks! */
5189 #if defined(CONFIG_PREEMPT)
5190 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
5192 task_thread_info(idle
)->preempt_count
= 0;
5195 * The idle tasks have their own, simple scheduling class:
5197 idle
->sched_class
= &idle_sched_class
;
5198 ftrace_graph_init_task(idle
);
5202 * In a system that switches off the HZ timer nohz_cpu_mask
5203 * indicates which cpus entered this state. This is used
5204 * in the rcu update to wait only for active cpus. For system
5205 * which do not switch off the HZ timer nohz_cpu_mask should
5206 * always be CPU_BITS_NONE.
5208 cpumask_var_t nohz_cpu_mask
;
5211 * Increase the granularity value when there are more CPUs,
5212 * because with more CPUs the 'effective latency' as visible
5213 * to users decreases. But the relationship is not linear,
5214 * so pick a second-best guess by going with the log2 of the
5217 * This idea comes from the SD scheduler of Con Kolivas:
5219 static int get_update_sysctl_factor(void)
5221 unsigned int cpus
= min_t(int, num_online_cpus(), 8);
5222 unsigned int factor
;
5224 switch (sysctl_sched_tunable_scaling
) {
5225 case SCHED_TUNABLESCALING_NONE
:
5228 case SCHED_TUNABLESCALING_LINEAR
:
5231 case SCHED_TUNABLESCALING_LOG
:
5233 factor
= 1 + ilog2(cpus
);
5240 static void update_sysctl(void)
5242 unsigned int factor
= get_update_sysctl_factor();
5244 #define SET_SYSCTL(name) \
5245 (sysctl_##name = (factor) * normalized_sysctl_##name)
5246 SET_SYSCTL(sched_min_granularity
);
5247 SET_SYSCTL(sched_latency
);
5248 SET_SYSCTL(sched_wakeup_granularity
);
5249 SET_SYSCTL(sched_shares_ratelimit
);
5253 static inline void sched_init_granularity(void)
5260 * This is how migration works:
5262 * 1) we queue a struct migration_req structure in the source CPU's
5263 * runqueue and wake up that CPU's migration thread.
5264 * 2) we down() the locked semaphore => thread blocks.
5265 * 3) migration thread wakes up (implicitly it forces the migrated
5266 * thread off the CPU)
5267 * 4) it gets the migration request and checks whether the migrated
5268 * task is still in the wrong runqueue.
5269 * 5) if it's in the wrong runqueue then the migration thread removes
5270 * it and puts it into the right queue.
5271 * 6) migration thread up()s the semaphore.
5272 * 7) we wake up and the migration is done.
5276 * Change a given task's CPU affinity. Migrate the thread to a
5277 * proper CPU and schedule it away if the CPU it's executing on
5278 * is removed from the allowed bitmask.
5280 * NOTE: the caller must have a valid reference to the task, the
5281 * task must not exit() & deallocate itself prematurely. The
5282 * call is not atomic; no spinlocks may be held.
5284 int set_cpus_allowed_ptr(struct task_struct
*p
, const struct cpumask
*new_mask
)
5286 struct migration_req req
;
5287 unsigned long flags
;
5292 * Since we rely on wake-ups to migrate sleeping tasks, don't change
5293 * the ->cpus_allowed mask from under waking tasks, which would be
5294 * possible when we change rq->lock in ttwu(), so synchronize against
5295 * TASK_WAKING to avoid that.
5298 while (p
->state
== TASK_WAKING
)
5301 rq
= task_rq_lock(p
, &flags
);
5303 if (p
->state
== TASK_WAKING
) {
5304 task_rq_unlock(rq
, &flags
);
5308 if (!cpumask_intersects(new_mask
, cpu_active_mask
)) {
5313 if (unlikely((p
->flags
& PF_THREAD_BOUND
) && p
!= current
&&
5314 !cpumask_equal(&p
->cpus_allowed
, new_mask
))) {
5319 if (p
->sched_class
->set_cpus_allowed
)
5320 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5322 cpumask_copy(&p
->cpus_allowed
, new_mask
);
5323 p
->rt
.nr_cpus_allowed
= cpumask_weight(new_mask
);
5326 /* Can the task run on the task's current CPU? If so, we're done */
5327 if (cpumask_test_cpu(task_cpu(p
), new_mask
))
5330 if (migrate_task(p
, cpumask_any_and(cpu_active_mask
, new_mask
), &req
)) {
5331 /* Need help from migration thread: drop lock and wait. */
5332 struct task_struct
*mt
= rq
->migration_thread
;
5334 get_task_struct(mt
);
5335 task_rq_unlock(rq
, &flags
);
5336 wake_up_process(rq
->migration_thread
);
5337 put_task_struct(mt
);
5338 wait_for_completion(&req
.done
);
5339 tlb_migrate_finish(p
->mm
);
5343 task_rq_unlock(rq
, &flags
);
5347 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5350 * Move (not current) task off this cpu, onto dest cpu. We're doing
5351 * this because either it can't run here any more (set_cpus_allowed()
5352 * away from this CPU, or CPU going down), or because we're
5353 * attempting to rebalance this task on exec (sched_exec).
5355 * So we race with normal scheduler movements, but that's OK, as long
5356 * as the task is no longer on this CPU.
5358 * Returns non-zero if task was successfully migrated.
5360 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5362 struct rq
*rq_dest
, *rq_src
;
5365 if (unlikely(!cpu_active(dest_cpu
)))
5368 rq_src
= cpu_rq(src_cpu
);
5369 rq_dest
= cpu_rq(dest_cpu
);
5371 double_rq_lock(rq_src
, rq_dest
);
5372 /* Already moved. */
5373 if (task_cpu(p
) != src_cpu
)
5375 /* Affinity changed (again). */
5376 if (!cpumask_test_cpu(dest_cpu
, &p
->cpus_allowed
))
5380 * If we're not on a rq, the next wake-up will ensure we're
5384 deactivate_task(rq_src
, p
, 0);
5385 set_task_cpu(p
, dest_cpu
);
5386 activate_task(rq_dest
, p
, 0);
5387 check_preempt_curr(rq_dest
, p
, 0);
5392 double_rq_unlock(rq_src
, rq_dest
);
5396 #define RCU_MIGRATION_IDLE 0
5397 #define RCU_MIGRATION_NEED_QS 1
5398 #define RCU_MIGRATION_GOT_QS 2
5399 #define RCU_MIGRATION_MUST_SYNC 3
5402 * migration_thread - this is a highprio system thread that performs
5403 * thread migration by bumping thread off CPU then 'pushing' onto
5406 static int migration_thread(void *data
)
5409 int cpu
= (long)data
;
5413 BUG_ON(rq
->migration_thread
!= current
);
5415 set_current_state(TASK_INTERRUPTIBLE
);
5416 while (!kthread_should_stop()) {
5417 struct migration_req
*req
;
5418 struct list_head
*head
;
5420 raw_spin_lock_irq(&rq
->lock
);
5422 if (cpu_is_offline(cpu
)) {
5423 raw_spin_unlock_irq(&rq
->lock
);
5427 if (rq
->active_balance
) {
5428 active_load_balance(rq
, cpu
);
5429 rq
->active_balance
= 0;
5432 head
= &rq
->migration_queue
;
5434 if (list_empty(head
)) {
5435 raw_spin_unlock_irq(&rq
->lock
);
5437 set_current_state(TASK_INTERRUPTIBLE
);
5440 req
= list_entry(head
->next
, struct migration_req
, list
);
5441 list_del_init(head
->next
);
5443 if (req
->task
!= NULL
) {
5444 raw_spin_unlock(&rq
->lock
);
5445 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
5446 } else if (likely(cpu
== (badcpu
= smp_processor_id()))) {
5447 req
->dest_cpu
= RCU_MIGRATION_GOT_QS
;
5448 raw_spin_unlock(&rq
->lock
);
5450 req
->dest_cpu
= RCU_MIGRATION_MUST_SYNC
;
5451 raw_spin_unlock(&rq
->lock
);
5452 WARN_ONCE(1, "migration_thread() on CPU %d, expected %d\n", badcpu
, cpu
);
5456 complete(&req
->done
);
5458 __set_current_state(TASK_RUNNING
);
5463 #ifdef CONFIG_HOTPLUG_CPU
5465 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5469 local_irq_disable();
5470 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
5476 * Figure out where task on dead CPU should go, use force if necessary.
5478 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5483 dest_cpu
= select_fallback_rq(dead_cpu
, p
);
5485 /* It can have affinity changed while we were choosing. */
5486 if (unlikely(!__migrate_task_irq(p
, dead_cpu
, dest_cpu
)))
5491 * While a dead CPU has no uninterruptible tasks queued at this point,
5492 * it might still have a nonzero ->nr_uninterruptible counter, because
5493 * for performance reasons the counter is not stricly tracking tasks to
5494 * their home CPUs. So we just add the counter to another CPU's counter,
5495 * to keep the global sum constant after CPU-down:
5497 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5499 struct rq
*rq_dest
= cpu_rq(cpumask_any(cpu_active_mask
));
5500 unsigned long flags
;
5502 local_irq_save(flags
);
5503 double_rq_lock(rq_src
, rq_dest
);
5504 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5505 rq_src
->nr_uninterruptible
= 0;
5506 double_rq_unlock(rq_src
, rq_dest
);
5507 local_irq_restore(flags
);
5510 /* Run through task list and migrate tasks from the dead cpu. */
5511 static void migrate_live_tasks(int src_cpu
)
5513 struct task_struct
*p
, *t
;
5515 read_lock(&tasklist_lock
);
5517 do_each_thread(t
, p
) {
5521 if (task_cpu(p
) == src_cpu
)
5522 move_task_off_dead_cpu(src_cpu
, p
);
5523 } while_each_thread(t
, p
);
5525 read_unlock(&tasklist_lock
);
5529 * Schedules idle task to be the next runnable task on current CPU.
5530 * It does so by boosting its priority to highest possible.
5531 * Used by CPU offline code.
5533 void sched_idle_next(void)
5535 int this_cpu
= smp_processor_id();
5536 struct rq
*rq
= cpu_rq(this_cpu
);
5537 struct task_struct
*p
= rq
->idle
;
5538 unsigned long flags
;
5540 /* cpu has to be offline */
5541 BUG_ON(cpu_online(this_cpu
));
5544 * Strictly not necessary since rest of the CPUs are stopped by now
5545 * and interrupts disabled on the current cpu.
5547 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5549 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5551 update_rq_clock(rq
);
5552 activate_task(rq
, p
, 0);
5554 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5558 * Ensures that the idle task is using init_mm right before its cpu goes
5561 void idle_task_exit(void)
5563 struct mm_struct
*mm
= current
->active_mm
;
5565 BUG_ON(cpu_online(smp_processor_id()));
5568 switch_mm(mm
, &init_mm
, current
);
5572 /* called under rq->lock with disabled interrupts */
5573 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5575 struct rq
*rq
= cpu_rq(dead_cpu
);
5577 /* Must be exiting, otherwise would be on tasklist. */
5578 BUG_ON(!p
->exit_state
);
5580 /* Cannot have done final schedule yet: would have vanished. */
5581 BUG_ON(p
->state
== TASK_DEAD
);
5586 * Drop lock around migration; if someone else moves it,
5587 * that's OK. No task can be added to this CPU, so iteration is
5590 raw_spin_unlock_irq(&rq
->lock
);
5591 move_task_off_dead_cpu(dead_cpu
, p
);
5592 raw_spin_lock_irq(&rq
->lock
);
5597 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5598 static void migrate_dead_tasks(unsigned int dead_cpu
)
5600 struct rq
*rq
= cpu_rq(dead_cpu
);
5601 struct task_struct
*next
;
5604 if (!rq
->nr_running
)
5606 update_rq_clock(rq
);
5607 next
= pick_next_task(rq
);
5610 next
->sched_class
->put_prev_task(rq
, next
);
5611 migrate_dead(dead_cpu
, next
);
5617 * remove the tasks which were accounted by rq from calc_load_tasks.
5619 static void calc_global_load_remove(struct rq
*rq
)
5621 atomic_long_sub(rq
->calc_load_active
, &calc_load_tasks
);
5622 rq
->calc_load_active
= 0;
5624 #endif /* CONFIG_HOTPLUG_CPU */
5626 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5628 static struct ctl_table sd_ctl_dir
[] = {
5630 .procname
= "sched_domain",
5636 static struct ctl_table sd_ctl_root
[] = {
5638 .procname
= "kernel",
5640 .child
= sd_ctl_dir
,
5645 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5647 struct ctl_table
*entry
=
5648 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5653 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5655 struct ctl_table
*entry
;
5658 * In the intermediate directories, both the child directory and
5659 * procname are dynamically allocated and could fail but the mode
5660 * will always be set. In the lowest directory the names are
5661 * static strings and all have proc handlers.
5663 for (entry
= *tablep
; entry
->mode
; entry
++) {
5665 sd_free_ctl_entry(&entry
->child
);
5666 if (entry
->proc_handler
== NULL
)
5667 kfree(entry
->procname
);
5675 set_table_entry(struct ctl_table
*entry
,
5676 const char *procname
, void *data
, int maxlen
,
5677 mode_t mode
, proc_handler
*proc_handler
)
5679 entry
->procname
= procname
;
5681 entry
->maxlen
= maxlen
;
5683 entry
->proc_handler
= proc_handler
;
5686 static struct ctl_table
*
5687 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5689 struct ctl_table
*table
= sd_alloc_ctl_entry(13);
5694 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5695 sizeof(long), 0644, proc_doulongvec_minmax
);
5696 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5697 sizeof(long), 0644, proc_doulongvec_minmax
);
5698 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5699 sizeof(int), 0644, proc_dointvec_minmax
);
5700 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5701 sizeof(int), 0644, proc_dointvec_minmax
);
5702 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5703 sizeof(int), 0644, proc_dointvec_minmax
);
5704 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5705 sizeof(int), 0644, proc_dointvec_minmax
);
5706 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5707 sizeof(int), 0644, proc_dointvec_minmax
);
5708 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5709 sizeof(int), 0644, proc_dointvec_minmax
);
5710 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5711 sizeof(int), 0644, proc_dointvec_minmax
);
5712 set_table_entry(&table
[9], "cache_nice_tries",
5713 &sd
->cache_nice_tries
,
5714 sizeof(int), 0644, proc_dointvec_minmax
);
5715 set_table_entry(&table
[10], "flags", &sd
->flags
,
5716 sizeof(int), 0644, proc_dointvec_minmax
);
5717 set_table_entry(&table
[11], "name", sd
->name
,
5718 CORENAME_MAX_SIZE
, 0444, proc_dostring
);
5719 /* &table[12] is terminator */
5724 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5726 struct ctl_table
*entry
, *table
;
5727 struct sched_domain
*sd
;
5728 int domain_num
= 0, i
;
5731 for_each_domain(cpu
, sd
)
5733 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
5738 for_each_domain(cpu
, sd
) {
5739 snprintf(buf
, 32, "domain%d", i
);
5740 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5742 entry
->child
= sd_alloc_ctl_domain_table(sd
);
5749 static struct ctl_table_header
*sd_sysctl_header
;
5750 static void register_sched_domain_sysctl(void)
5752 int i
, cpu_num
= num_possible_cpus();
5753 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
5756 WARN_ON(sd_ctl_dir
[0].child
);
5757 sd_ctl_dir
[0].child
= entry
;
5762 for_each_possible_cpu(i
) {
5763 snprintf(buf
, 32, "cpu%d", i
);
5764 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
5766 entry
->child
= sd_alloc_ctl_cpu_table(i
);
5770 WARN_ON(sd_sysctl_header
);
5771 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
5774 /* may be called multiple times per register */
5775 static void unregister_sched_domain_sysctl(void)
5777 if (sd_sysctl_header
)
5778 unregister_sysctl_table(sd_sysctl_header
);
5779 sd_sysctl_header
= NULL
;
5780 if (sd_ctl_dir
[0].child
)
5781 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
5784 static void register_sched_domain_sysctl(void)
5787 static void unregister_sched_domain_sysctl(void)
5792 static void set_rq_online(struct rq
*rq
)
5795 const struct sched_class
*class;
5797 cpumask_set_cpu(rq
->cpu
, rq
->rd
->online
);
5800 for_each_class(class) {
5801 if (class->rq_online
)
5802 class->rq_online(rq
);
5807 static void set_rq_offline(struct rq
*rq
)
5810 const struct sched_class
*class;
5812 for_each_class(class) {
5813 if (class->rq_offline
)
5814 class->rq_offline(rq
);
5817 cpumask_clear_cpu(rq
->cpu
, rq
->rd
->online
);
5823 * migration_call - callback that gets triggered when a CPU is added.
5824 * Here we can start up the necessary migration thread for the new CPU.
5826 static int __cpuinit
5827 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
5829 struct task_struct
*p
;
5830 int cpu
= (long)hcpu
;
5831 unsigned long flags
;
5836 case CPU_UP_PREPARE
:
5837 case CPU_UP_PREPARE_FROZEN
:
5838 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
5841 kthread_bind(p
, cpu
);
5842 /* Must be high prio: stop_machine expects to yield to it. */
5843 rq
= task_rq_lock(p
, &flags
);
5844 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5845 task_rq_unlock(rq
, &flags
);
5847 cpu_rq(cpu
)->migration_thread
= p
;
5848 rq
->calc_load_update
= calc_load_update
;
5852 case CPU_ONLINE_FROZEN
:
5853 /* Strictly unnecessary, as first user will wake it. */
5854 wake_up_process(cpu_rq(cpu
)->migration_thread
);
5856 /* Update our root-domain */
5858 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5860 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5864 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5867 #ifdef CONFIG_HOTPLUG_CPU
5868 case CPU_UP_CANCELED
:
5869 case CPU_UP_CANCELED_FROZEN
:
5870 if (!cpu_rq(cpu
)->migration_thread
)
5872 /* Unbind it from offline cpu so it can run. Fall thru. */
5873 kthread_bind(cpu_rq(cpu
)->migration_thread
,
5874 cpumask_any(cpu_online_mask
));
5875 kthread_stop(cpu_rq(cpu
)->migration_thread
);
5876 put_task_struct(cpu_rq(cpu
)->migration_thread
);
5877 cpu_rq(cpu
)->migration_thread
= NULL
;
5881 case CPU_DEAD_FROZEN
:
5882 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
5883 migrate_live_tasks(cpu
);
5885 kthread_stop(rq
->migration_thread
);
5886 put_task_struct(rq
->migration_thread
);
5887 rq
->migration_thread
= NULL
;
5888 /* Idle task back to normal (off runqueue, low prio) */
5889 raw_spin_lock_irq(&rq
->lock
);
5890 update_rq_clock(rq
);
5891 deactivate_task(rq
, rq
->idle
, 0);
5892 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
5893 rq
->idle
->sched_class
= &idle_sched_class
;
5894 migrate_dead_tasks(cpu
);
5895 raw_spin_unlock_irq(&rq
->lock
);
5897 migrate_nr_uninterruptible(rq
);
5898 BUG_ON(rq
->nr_running
!= 0);
5899 calc_global_load_remove(rq
);
5901 * No need to migrate the tasks: it was best-effort if
5902 * they didn't take sched_hotcpu_mutex. Just wake up
5905 raw_spin_lock_irq(&rq
->lock
);
5906 while (!list_empty(&rq
->migration_queue
)) {
5907 struct migration_req
*req
;
5909 req
= list_entry(rq
->migration_queue
.next
,
5910 struct migration_req
, list
);
5911 list_del_init(&req
->list
);
5912 raw_spin_unlock_irq(&rq
->lock
);
5913 complete(&req
->done
);
5914 raw_spin_lock_irq(&rq
->lock
);
5916 raw_spin_unlock_irq(&rq
->lock
);
5920 case CPU_DYING_FROZEN
:
5921 /* Update our root-domain */
5923 raw_spin_lock_irqsave(&rq
->lock
, flags
);
5925 BUG_ON(!cpumask_test_cpu(cpu
, rq
->rd
->span
));
5928 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
5936 * Register at high priority so that task migration (migrate_all_tasks)
5937 * happens before everything else. This has to be lower priority than
5938 * the notifier in the perf_event subsystem, though.
5940 static struct notifier_block __cpuinitdata migration_notifier
= {
5941 .notifier_call
= migration_call
,
5945 static int __init
migration_init(void)
5947 void *cpu
= (void *)(long)smp_processor_id();
5950 /* Start one for the boot CPU: */
5951 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
5952 BUG_ON(err
== NOTIFY_BAD
);
5953 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
5954 register_cpu_notifier(&migration_notifier
);
5958 early_initcall(migration_init
);
5963 #ifdef CONFIG_SCHED_DEBUG
5965 static __read_mostly
int sched_domain_debug_enabled
;
5967 static int __init
sched_domain_debug_setup(char *str
)
5969 sched_domain_debug_enabled
= 1;
5973 early_param("sched_debug", sched_domain_debug_setup
);
5975 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
5976 struct cpumask
*groupmask
)
5978 struct sched_group
*group
= sd
->groups
;
5981 cpulist_scnprintf(str
, sizeof(str
), sched_domain_span(sd
));
5982 cpumask_clear(groupmask
);
5984 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
5986 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
5987 printk("does not load-balance\n");
5989 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
5994 printk(KERN_CONT
"span %s level %s\n", str
, sd
->name
);
5996 if (!cpumask_test_cpu(cpu
, sched_domain_span(sd
))) {
5997 printk(KERN_ERR
"ERROR: domain->span does not contain "
6000 if (!cpumask_test_cpu(cpu
, sched_group_cpus(group
))) {
6001 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6005 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6009 printk(KERN_ERR
"ERROR: group is NULL\n");
6013 if (!group
->cpu_power
) {
6014 printk(KERN_CONT
"\n");
6015 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6020 if (!cpumask_weight(sched_group_cpus(group
))) {
6021 printk(KERN_CONT
"\n");
6022 printk(KERN_ERR
"ERROR: empty group\n");
6026 if (cpumask_intersects(groupmask
, sched_group_cpus(group
))) {
6027 printk(KERN_CONT
"\n");
6028 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6032 cpumask_or(groupmask
, groupmask
, sched_group_cpus(group
));
6034 cpulist_scnprintf(str
, sizeof(str
), sched_group_cpus(group
));
6036 printk(KERN_CONT
" %s", str
);
6037 if (group
->cpu_power
!= SCHED_LOAD_SCALE
) {
6038 printk(KERN_CONT
" (cpu_power = %d)",
6042 group
= group
->next
;
6043 } while (group
!= sd
->groups
);
6044 printk(KERN_CONT
"\n");
6046 if (!cpumask_equal(sched_domain_span(sd
), groupmask
))
6047 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6050 !cpumask_subset(groupmask
, sched_domain_span(sd
->parent
)))
6051 printk(KERN_ERR
"ERROR: parent span is not a superset "
6052 "of domain->span\n");
6056 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6058 cpumask_var_t groupmask
;
6061 if (!sched_domain_debug_enabled
)
6065 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6069 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6071 if (!alloc_cpumask_var(&groupmask
, GFP_KERNEL
)) {
6072 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6077 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6084 free_cpumask_var(groupmask
);
6086 #else /* !CONFIG_SCHED_DEBUG */
6087 # define sched_domain_debug(sd, cpu) do { } while (0)
6088 #endif /* CONFIG_SCHED_DEBUG */
6090 static int sd_degenerate(struct sched_domain
*sd
)
6092 if (cpumask_weight(sched_domain_span(sd
)) == 1)
6095 /* Following flags need at least 2 groups */
6096 if (sd
->flags
& (SD_LOAD_BALANCE
|
6097 SD_BALANCE_NEWIDLE
|
6101 SD_SHARE_PKG_RESOURCES
)) {
6102 if (sd
->groups
!= sd
->groups
->next
)
6106 /* Following flags don't use groups */
6107 if (sd
->flags
& (SD_WAKE_AFFINE
))
6114 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6116 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6118 if (sd_degenerate(parent
))
6121 if (!cpumask_equal(sched_domain_span(sd
), sched_domain_span(parent
)))
6124 /* Flags needing groups don't count if only 1 group in parent */
6125 if (parent
->groups
== parent
->groups
->next
) {
6126 pflags
&= ~(SD_LOAD_BALANCE
|
6127 SD_BALANCE_NEWIDLE
|
6131 SD_SHARE_PKG_RESOURCES
);
6132 if (nr_node_ids
== 1)
6133 pflags
&= ~SD_SERIALIZE
;
6135 if (~cflags
& pflags
)
6141 static void free_rootdomain(struct root_domain
*rd
)
6143 synchronize_sched();
6145 cpupri_cleanup(&rd
->cpupri
);
6147 free_cpumask_var(rd
->rto_mask
);
6148 free_cpumask_var(rd
->online
);
6149 free_cpumask_var(rd
->span
);
6153 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6155 struct root_domain
*old_rd
= NULL
;
6156 unsigned long flags
;
6158 raw_spin_lock_irqsave(&rq
->lock
, flags
);
6163 if (cpumask_test_cpu(rq
->cpu
, old_rd
->online
))
6166 cpumask_clear_cpu(rq
->cpu
, old_rd
->span
);
6169 * If we dont want to free the old_rt yet then
6170 * set old_rd to NULL to skip the freeing later
6173 if (!atomic_dec_and_test(&old_rd
->refcount
))
6177 atomic_inc(&rd
->refcount
);
6180 cpumask_set_cpu(rq
->cpu
, rd
->span
);
6181 if (cpumask_test_cpu(rq
->cpu
, cpu_active_mask
))
6184 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
6187 free_rootdomain(old_rd
);
6190 static int init_rootdomain(struct root_domain
*rd
, bool bootmem
)
6192 gfp_t gfp
= GFP_KERNEL
;
6194 memset(rd
, 0, sizeof(*rd
));
6199 if (!alloc_cpumask_var(&rd
->span
, gfp
))
6201 if (!alloc_cpumask_var(&rd
->online
, gfp
))
6203 if (!alloc_cpumask_var(&rd
->rto_mask
, gfp
))
6206 if (cpupri_init(&rd
->cpupri
, bootmem
) != 0)
6211 free_cpumask_var(rd
->rto_mask
);
6213 free_cpumask_var(rd
->online
);
6215 free_cpumask_var(rd
->span
);
6220 static void init_defrootdomain(void)
6222 init_rootdomain(&def_root_domain
, true);
6224 atomic_set(&def_root_domain
.refcount
, 1);
6227 static struct root_domain
*alloc_rootdomain(void)
6229 struct root_domain
*rd
;
6231 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6235 if (init_rootdomain(rd
, false) != 0) {
6244 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6245 * hold the hotplug lock.
6248 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6250 struct rq
*rq
= cpu_rq(cpu
);
6251 struct sched_domain
*tmp
;
6253 /* Remove the sched domains which do not contribute to scheduling. */
6254 for (tmp
= sd
; tmp
; ) {
6255 struct sched_domain
*parent
= tmp
->parent
;
6259 if (sd_parent_degenerate(tmp
, parent
)) {
6260 tmp
->parent
= parent
->parent
;
6262 parent
->parent
->child
= tmp
;
6267 if (sd
&& sd_degenerate(sd
)) {
6273 sched_domain_debug(sd
, cpu
);
6275 rq_attach_root(rq
, rd
);
6276 rcu_assign_pointer(rq
->sd
, sd
);
6279 /* cpus with isolated domains */
6280 static cpumask_var_t cpu_isolated_map
;
6282 /* Setup the mask of cpus configured for isolated domains */
6283 static int __init
isolated_cpu_setup(char *str
)
6285 alloc_bootmem_cpumask_var(&cpu_isolated_map
);
6286 cpulist_parse(str
, cpu_isolated_map
);
6290 __setup("isolcpus=", isolated_cpu_setup
);
6293 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6294 * to a function which identifies what group(along with sched group) a CPU
6295 * belongs to. The return value of group_fn must be a >= 0 and < nr_cpu_ids
6296 * (due to the fact that we keep track of groups covered with a struct cpumask).
6298 * init_sched_build_groups will build a circular linked list of the groups
6299 * covered by the given span, and will set each group's ->cpumask correctly,
6300 * and ->cpu_power to 0.
6303 init_sched_build_groups(const struct cpumask
*span
,
6304 const struct cpumask
*cpu_map
,
6305 int (*group_fn
)(int cpu
, const struct cpumask
*cpu_map
,
6306 struct sched_group
**sg
,
6307 struct cpumask
*tmpmask
),
6308 struct cpumask
*covered
, struct cpumask
*tmpmask
)
6310 struct sched_group
*first
= NULL
, *last
= NULL
;
6313 cpumask_clear(covered
);
6315 for_each_cpu(i
, span
) {
6316 struct sched_group
*sg
;
6317 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6320 if (cpumask_test_cpu(i
, covered
))
6323 cpumask_clear(sched_group_cpus(sg
));
6326 for_each_cpu(j
, span
) {
6327 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6330 cpumask_set_cpu(j
, covered
);
6331 cpumask_set_cpu(j
, sched_group_cpus(sg
));
6342 #define SD_NODES_PER_DOMAIN 16
6347 * find_next_best_node - find the next node to include in a sched_domain
6348 * @node: node whose sched_domain we're building
6349 * @used_nodes: nodes already in the sched_domain
6351 * Find the next node to include in a given scheduling domain. Simply
6352 * finds the closest node not already in the @used_nodes map.
6354 * Should use nodemask_t.
6356 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6358 int i
, n
, val
, min_val
, best_node
= 0;
6362 for (i
= 0; i
< nr_node_ids
; i
++) {
6363 /* Start at @node */
6364 n
= (node
+ i
) % nr_node_ids
;
6366 if (!nr_cpus_node(n
))
6369 /* Skip already used nodes */
6370 if (node_isset(n
, *used_nodes
))
6373 /* Simple min distance search */
6374 val
= node_distance(node
, n
);
6376 if (val
< min_val
) {
6382 node_set(best_node
, *used_nodes
);
6387 * sched_domain_node_span - get a cpumask for a node's sched_domain
6388 * @node: node whose cpumask we're constructing
6389 * @span: resulting cpumask
6391 * Given a node, construct a good cpumask for its sched_domain to span. It
6392 * should be one that prevents unnecessary balancing, but also spreads tasks
6395 static void sched_domain_node_span(int node
, struct cpumask
*span
)
6397 nodemask_t used_nodes
;
6400 cpumask_clear(span
);
6401 nodes_clear(used_nodes
);
6403 cpumask_or(span
, span
, cpumask_of_node(node
));
6404 node_set(node
, used_nodes
);
6406 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6407 int next_node
= find_next_best_node(node
, &used_nodes
);
6409 cpumask_or(span
, span
, cpumask_of_node(next_node
));
6412 #endif /* CONFIG_NUMA */
6414 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6417 * The cpus mask in sched_group and sched_domain hangs off the end.
6419 * ( See the the comments in include/linux/sched.h:struct sched_group
6420 * and struct sched_domain. )
6422 struct static_sched_group
{
6423 struct sched_group sg
;
6424 DECLARE_BITMAP(cpus
, CONFIG_NR_CPUS
);
6427 struct static_sched_domain
{
6428 struct sched_domain sd
;
6429 DECLARE_BITMAP(span
, CONFIG_NR_CPUS
);
6435 cpumask_var_t domainspan
;
6436 cpumask_var_t covered
;
6437 cpumask_var_t notcovered
;
6439 cpumask_var_t nodemask
;
6440 cpumask_var_t this_sibling_map
;
6441 cpumask_var_t this_core_map
;
6442 cpumask_var_t send_covered
;
6443 cpumask_var_t tmpmask
;
6444 struct sched_group
**sched_group_nodes
;
6445 struct root_domain
*rd
;
6449 sa_sched_groups
= 0,
6454 sa_this_sibling_map
,
6456 sa_sched_group_nodes
,
6466 * SMT sched-domains:
6468 #ifdef CONFIG_SCHED_SMT
6469 static DEFINE_PER_CPU(struct static_sched_domain
, cpu_domains
);
6470 static DEFINE_PER_CPU(struct static_sched_group
, sched_groups
);
6473 cpu_to_cpu_group(int cpu
, const struct cpumask
*cpu_map
,
6474 struct sched_group
**sg
, struct cpumask
*unused
)
6477 *sg
= &per_cpu(sched_groups
, cpu
).sg
;
6480 #endif /* CONFIG_SCHED_SMT */
6483 * multi-core sched-domains:
6485 #ifdef CONFIG_SCHED_MC
6486 static DEFINE_PER_CPU(struct static_sched_domain
, core_domains
);
6487 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_core
);
6488 #endif /* CONFIG_SCHED_MC */
6490 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6492 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
6493 struct sched_group
**sg
, struct cpumask
*mask
)
6497 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6498 group
= cpumask_first(mask
);
6500 *sg
= &per_cpu(sched_group_core
, group
).sg
;
6503 #elif defined(CONFIG_SCHED_MC)
6505 cpu_to_core_group(int cpu
, const struct cpumask
*cpu_map
,
6506 struct sched_group
**sg
, struct cpumask
*unused
)
6509 *sg
= &per_cpu(sched_group_core
, cpu
).sg
;
6514 static DEFINE_PER_CPU(struct static_sched_domain
, phys_domains
);
6515 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_phys
);
6518 cpu_to_phys_group(int cpu
, const struct cpumask
*cpu_map
,
6519 struct sched_group
**sg
, struct cpumask
*mask
)
6522 #ifdef CONFIG_SCHED_MC
6523 cpumask_and(mask
, cpu_coregroup_mask(cpu
), cpu_map
);
6524 group
= cpumask_first(mask
);
6525 #elif defined(CONFIG_SCHED_SMT)
6526 cpumask_and(mask
, topology_thread_cpumask(cpu
), cpu_map
);
6527 group
= cpumask_first(mask
);
6532 *sg
= &per_cpu(sched_group_phys
, group
).sg
;
6538 * The init_sched_build_groups can't handle what we want to do with node
6539 * groups, so roll our own. Now each node has its own list of groups which
6540 * gets dynamically allocated.
6542 static DEFINE_PER_CPU(struct static_sched_domain
, node_domains
);
6543 static struct sched_group
***sched_group_nodes_bycpu
;
6545 static DEFINE_PER_CPU(struct static_sched_domain
, allnodes_domains
);
6546 static DEFINE_PER_CPU(struct static_sched_group
, sched_group_allnodes
);
6548 static int cpu_to_allnodes_group(int cpu
, const struct cpumask
*cpu_map
,
6549 struct sched_group
**sg
,
6550 struct cpumask
*nodemask
)
6554 cpumask_and(nodemask
, cpumask_of_node(cpu_to_node(cpu
)), cpu_map
);
6555 group
= cpumask_first(nodemask
);
6558 *sg
= &per_cpu(sched_group_allnodes
, group
).sg
;
6562 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6564 struct sched_group
*sg
= group_head
;
6570 for_each_cpu(j
, sched_group_cpus(sg
)) {
6571 struct sched_domain
*sd
;
6573 sd
= &per_cpu(phys_domains
, j
).sd
;
6574 if (j
!= group_first_cpu(sd
->groups
)) {
6576 * Only add "power" once for each
6582 sg
->cpu_power
+= sd
->groups
->cpu_power
;
6585 } while (sg
!= group_head
);
6588 static int build_numa_sched_groups(struct s_data
*d
,
6589 const struct cpumask
*cpu_map
, int num
)
6591 struct sched_domain
*sd
;
6592 struct sched_group
*sg
, *prev
;
6595 cpumask_clear(d
->covered
);
6596 cpumask_and(d
->nodemask
, cpumask_of_node(num
), cpu_map
);
6597 if (cpumask_empty(d
->nodemask
)) {
6598 d
->sched_group_nodes
[num
] = NULL
;
6602 sched_domain_node_span(num
, d
->domainspan
);
6603 cpumask_and(d
->domainspan
, d
->domainspan
, cpu_map
);
6605 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6608 printk(KERN_WARNING
"Can not alloc domain group for node %d\n",
6612 d
->sched_group_nodes
[num
] = sg
;
6614 for_each_cpu(j
, d
->nodemask
) {
6615 sd
= &per_cpu(node_domains
, j
).sd
;
6620 cpumask_copy(sched_group_cpus(sg
), d
->nodemask
);
6622 cpumask_or(d
->covered
, d
->covered
, d
->nodemask
);
6625 for (j
= 0; j
< nr_node_ids
; j
++) {
6626 n
= (num
+ j
) % nr_node_ids
;
6627 cpumask_complement(d
->notcovered
, d
->covered
);
6628 cpumask_and(d
->tmpmask
, d
->notcovered
, cpu_map
);
6629 cpumask_and(d
->tmpmask
, d
->tmpmask
, d
->domainspan
);
6630 if (cpumask_empty(d
->tmpmask
))
6632 cpumask_and(d
->tmpmask
, d
->tmpmask
, cpumask_of_node(n
));
6633 if (cpumask_empty(d
->tmpmask
))
6635 sg
= kmalloc_node(sizeof(struct sched_group
) + cpumask_size(),
6639 "Can not alloc domain group for node %d\n", j
);
6643 cpumask_copy(sched_group_cpus(sg
), d
->tmpmask
);
6644 sg
->next
= prev
->next
;
6645 cpumask_or(d
->covered
, d
->covered
, d
->tmpmask
);
6652 #endif /* CONFIG_NUMA */
6655 /* Free memory allocated for various sched_group structures */
6656 static void free_sched_groups(const struct cpumask
*cpu_map
,
6657 struct cpumask
*nodemask
)
6661 for_each_cpu(cpu
, cpu_map
) {
6662 struct sched_group
**sched_group_nodes
6663 = sched_group_nodes_bycpu
[cpu
];
6665 if (!sched_group_nodes
)
6668 for (i
= 0; i
< nr_node_ids
; i
++) {
6669 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6671 cpumask_and(nodemask
, cpumask_of_node(i
), cpu_map
);
6672 if (cpumask_empty(nodemask
))
6682 if (oldsg
!= sched_group_nodes
[i
])
6685 kfree(sched_group_nodes
);
6686 sched_group_nodes_bycpu
[cpu
] = NULL
;
6689 #else /* !CONFIG_NUMA */
6690 static void free_sched_groups(const struct cpumask
*cpu_map
,
6691 struct cpumask
*nodemask
)
6694 #endif /* CONFIG_NUMA */
6697 * Initialize sched groups cpu_power.
6699 * cpu_power indicates the capacity of sched group, which is used while
6700 * distributing the load between different sched groups in a sched domain.
6701 * Typically cpu_power for all the groups in a sched domain will be same unless
6702 * there are asymmetries in the topology. If there are asymmetries, group
6703 * having more cpu_power will pickup more load compared to the group having
6706 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6708 struct sched_domain
*child
;
6709 struct sched_group
*group
;
6713 WARN_ON(!sd
|| !sd
->groups
);
6715 if (cpu
!= group_first_cpu(sd
->groups
))
6720 sd
->groups
->cpu_power
= 0;
6723 power
= SCHED_LOAD_SCALE
;
6724 weight
= cpumask_weight(sched_domain_span(sd
));
6726 * SMT siblings share the power of a single core.
6727 * Usually multiple threads get a better yield out of
6728 * that one core than a single thread would have,
6729 * reflect that in sd->smt_gain.
6731 if ((sd
->flags
& SD_SHARE_CPUPOWER
) && weight
> 1) {
6732 power
*= sd
->smt_gain
;
6734 power
>>= SCHED_LOAD_SHIFT
;
6736 sd
->groups
->cpu_power
+= power
;
6741 * Add cpu_power of each child group to this groups cpu_power.
6743 group
= child
->groups
;
6745 sd
->groups
->cpu_power
+= group
->cpu_power
;
6746 group
= group
->next
;
6747 } while (group
!= child
->groups
);
6751 * Initializers for schedule domains
6752 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6755 #ifdef CONFIG_SCHED_DEBUG
6756 # define SD_INIT_NAME(sd, type) sd->name = #type
6758 # define SD_INIT_NAME(sd, type) do { } while (0)
6761 #define SD_INIT(sd, type) sd_init_##type(sd)
6763 #define SD_INIT_FUNC(type) \
6764 static noinline void sd_init_##type(struct sched_domain *sd) \
6766 memset(sd, 0, sizeof(*sd)); \
6767 *sd = SD_##type##_INIT; \
6768 sd->level = SD_LV_##type; \
6769 SD_INIT_NAME(sd, type); \
6774 SD_INIT_FUNC(ALLNODES
)
6777 #ifdef CONFIG_SCHED_SMT
6778 SD_INIT_FUNC(SIBLING
)
6780 #ifdef CONFIG_SCHED_MC
6784 static int default_relax_domain_level
= -1;
6786 static int __init
setup_relax_domain_level(char *str
)
6790 val
= simple_strtoul(str
, NULL
, 0);
6791 if (val
< SD_LV_MAX
)
6792 default_relax_domain_level
= val
;
6796 __setup("relax_domain_level=", setup_relax_domain_level
);
6798 static void set_domain_attribute(struct sched_domain
*sd
,
6799 struct sched_domain_attr
*attr
)
6803 if (!attr
|| attr
->relax_domain_level
< 0) {
6804 if (default_relax_domain_level
< 0)
6807 request
= default_relax_domain_level
;
6809 request
= attr
->relax_domain_level
;
6810 if (request
< sd
->level
) {
6811 /* turn off idle balance on this domain */
6812 sd
->flags
&= ~(SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6814 /* turn on idle balance on this domain */
6815 sd
->flags
|= (SD_BALANCE_WAKE
|SD_BALANCE_NEWIDLE
);
6819 static void __free_domain_allocs(struct s_data
*d
, enum s_alloc what
,
6820 const struct cpumask
*cpu_map
)
6823 case sa_sched_groups
:
6824 free_sched_groups(cpu_map
, d
->tmpmask
); /* fall through */
6825 d
->sched_group_nodes
= NULL
;
6827 free_rootdomain(d
->rd
); /* fall through */
6829 free_cpumask_var(d
->tmpmask
); /* fall through */
6830 case sa_send_covered
:
6831 free_cpumask_var(d
->send_covered
); /* fall through */
6832 case sa_this_core_map
:
6833 free_cpumask_var(d
->this_core_map
); /* fall through */
6834 case sa_this_sibling_map
:
6835 free_cpumask_var(d
->this_sibling_map
); /* fall through */
6837 free_cpumask_var(d
->nodemask
); /* fall through */
6838 case sa_sched_group_nodes
:
6840 kfree(d
->sched_group_nodes
); /* fall through */
6842 free_cpumask_var(d
->notcovered
); /* fall through */
6844 free_cpumask_var(d
->covered
); /* fall through */
6846 free_cpumask_var(d
->domainspan
); /* fall through */
6853 static enum s_alloc
__visit_domain_allocation_hell(struct s_data
*d
,
6854 const struct cpumask
*cpu_map
)
6857 if (!alloc_cpumask_var(&d
->domainspan
, GFP_KERNEL
))
6859 if (!alloc_cpumask_var(&d
->covered
, GFP_KERNEL
))
6860 return sa_domainspan
;
6861 if (!alloc_cpumask_var(&d
->notcovered
, GFP_KERNEL
))
6863 /* Allocate the per-node list of sched groups */
6864 d
->sched_group_nodes
= kcalloc(nr_node_ids
,
6865 sizeof(struct sched_group
*), GFP_KERNEL
);
6866 if (!d
->sched_group_nodes
) {
6867 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6868 return sa_notcovered
;
6870 sched_group_nodes_bycpu
[cpumask_first(cpu_map
)] = d
->sched_group_nodes
;
6872 if (!alloc_cpumask_var(&d
->nodemask
, GFP_KERNEL
))
6873 return sa_sched_group_nodes
;
6874 if (!alloc_cpumask_var(&d
->this_sibling_map
, GFP_KERNEL
))
6876 if (!alloc_cpumask_var(&d
->this_core_map
, GFP_KERNEL
))
6877 return sa_this_sibling_map
;
6878 if (!alloc_cpumask_var(&d
->send_covered
, GFP_KERNEL
))
6879 return sa_this_core_map
;
6880 if (!alloc_cpumask_var(&d
->tmpmask
, GFP_KERNEL
))
6881 return sa_send_covered
;
6882 d
->rd
= alloc_rootdomain();
6884 printk(KERN_WARNING
"Cannot alloc root domain\n");
6887 return sa_rootdomain
;
6890 static struct sched_domain
*__build_numa_sched_domains(struct s_data
*d
,
6891 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
, int i
)
6893 struct sched_domain
*sd
= NULL
;
6895 struct sched_domain
*parent
;
6898 if (cpumask_weight(cpu_map
) >
6899 SD_NODES_PER_DOMAIN
* cpumask_weight(d
->nodemask
)) {
6900 sd
= &per_cpu(allnodes_domains
, i
).sd
;
6901 SD_INIT(sd
, ALLNODES
);
6902 set_domain_attribute(sd
, attr
);
6903 cpumask_copy(sched_domain_span(sd
), cpu_map
);
6904 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
6909 sd
= &per_cpu(node_domains
, i
).sd
;
6911 set_domain_attribute(sd
, attr
);
6912 sched_domain_node_span(cpu_to_node(i
), sched_domain_span(sd
));
6913 sd
->parent
= parent
;
6916 cpumask_and(sched_domain_span(sd
), sched_domain_span(sd
), cpu_map
);
6921 static struct sched_domain
*__build_cpu_sched_domain(struct s_data
*d
,
6922 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6923 struct sched_domain
*parent
, int i
)
6925 struct sched_domain
*sd
;
6926 sd
= &per_cpu(phys_domains
, i
).sd
;
6928 set_domain_attribute(sd
, attr
);
6929 cpumask_copy(sched_domain_span(sd
), d
->nodemask
);
6930 sd
->parent
= parent
;
6933 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
6937 static struct sched_domain
*__build_mc_sched_domain(struct s_data
*d
,
6938 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6939 struct sched_domain
*parent
, int i
)
6941 struct sched_domain
*sd
= parent
;
6942 #ifdef CONFIG_SCHED_MC
6943 sd
= &per_cpu(core_domains
, i
).sd
;
6945 set_domain_attribute(sd
, attr
);
6946 cpumask_and(sched_domain_span(sd
), cpu_map
, cpu_coregroup_mask(i
));
6947 sd
->parent
= parent
;
6949 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
6954 static struct sched_domain
*__build_smt_sched_domain(struct s_data
*d
,
6955 const struct cpumask
*cpu_map
, struct sched_domain_attr
*attr
,
6956 struct sched_domain
*parent
, int i
)
6958 struct sched_domain
*sd
= parent
;
6959 #ifdef CONFIG_SCHED_SMT
6960 sd
= &per_cpu(cpu_domains
, i
).sd
;
6961 SD_INIT(sd
, SIBLING
);
6962 set_domain_attribute(sd
, attr
);
6963 cpumask_and(sched_domain_span(sd
), cpu_map
, topology_thread_cpumask(i
));
6964 sd
->parent
= parent
;
6966 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, d
->tmpmask
);
6971 static void build_sched_groups(struct s_data
*d
, enum sched_domain_level l
,
6972 const struct cpumask
*cpu_map
, int cpu
)
6975 #ifdef CONFIG_SCHED_SMT
6976 case SD_LV_SIBLING
: /* set up CPU (sibling) groups */
6977 cpumask_and(d
->this_sibling_map
, cpu_map
,
6978 topology_thread_cpumask(cpu
));
6979 if (cpu
== cpumask_first(d
->this_sibling_map
))
6980 init_sched_build_groups(d
->this_sibling_map
, cpu_map
,
6982 d
->send_covered
, d
->tmpmask
);
6985 #ifdef CONFIG_SCHED_MC
6986 case SD_LV_MC
: /* set up multi-core groups */
6987 cpumask_and(d
->this_core_map
, cpu_map
, cpu_coregroup_mask(cpu
));
6988 if (cpu
== cpumask_first(d
->this_core_map
))
6989 init_sched_build_groups(d
->this_core_map
, cpu_map
,
6991 d
->send_covered
, d
->tmpmask
);
6994 case SD_LV_CPU
: /* set up physical groups */
6995 cpumask_and(d
->nodemask
, cpumask_of_node(cpu
), cpu_map
);
6996 if (!cpumask_empty(d
->nodemask
))
6997 init_sched_build_groups(d
->nodemask
, cpu_map
,
6999 d
->send_covered
, d
->tmpmask
);
7002 case SD_LV_ALLNODES
:
7003 init_sched_build_groups(cpu_map
, cpu_map
, &cpu_to_allnodes_group
,
7004 d
->send_covered
, d
->tmpmask
);
7013 * Build sched domains for a given set of cpus and attach the sched domains
7014 * to the individual cpus
7016 static int __build_sched_domains(const struct cpumask
*cpu_map
,
7017 struct sched_domain_attr
*attr
)
7019 enum s_alloc alloc_state
= sa_none
;
7021 struct sched_domain
*sd
;
7027 alloc_state
= __visit_domain_allocation_hell(&d
, cpu_map
);
7028 if (alloc_state
!= sa_rootdomain
)
7030 alloc_state
= sa_sched_groups
;
7033 * Set up domains for cpus specified by the cpu_map.
7035 for_each_cpu(i
, cpu_map
) {
7036 cpumask_and(d
.nodemask
, cpumask_of_node(cpu_to_node(i
)),
7039 sd
= __build_numa_sched_domains(&d
, cpu_map
, attr
, i
);
7040 sd
= __build_cpu_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7041 sd
= __build_mc_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7042 sd
= __build_smt_sched_domain(&d
, cpu_map
, attr
, sd
, i
);
7045 for_each_cpu(i
, cpu_map
) {
7046 build_sched_groups(&d
, SD_LV_SIBLING
, cpu_map
, i
);
7047 build_sched_groups(&d
, SD_LV_MC
, cpu_map
, i
);
7050 /* Set up physical groups */
7051 for (i
= 0; i
< nr_node_ids
; i
++)
7052 build_sched_groups(&d
, SD_LV_CPU
, cpu_map
, i
);
7055 /* Set up node groups */
7057 build_sched_groups(&d
, SD_LV_ALLNODES
, cpu_map
, 0);
7059 for (i
= 0; i
< nr_node_ids
; i
++)
7060 if (build_numa_sched_groups(&d
, cpu_map
, i
))
7064 /* Calculate CPU power for physical packages and nodes */
7065 #ifdef CONFIG_SCHED_SMT
7066 for_each_cpu(i
, cpu_map
) {
7067 sd
= &per_cpu(cpu_domains
, i
).sd
;
7068 init_sched_groups_power(i
, sd
);
7071 #ifdef CONFIG_SCHED_MC
7072 for_each_cpu(i
, cpu_map
) {
7073 sd
= &per_cpu(core_domains
, i
).sd
;
7074 init_sched_groups_power(i
, sd
);
7078 for_each_cpu(i
, cpu_map
) {
7079 sd
= &per_cpu(phys_domains
, i
).sd
;
7080 init_sched_groups_power(i
, sd
);
7084 for (i
= 0; i
< nr_node_ids
; i
++)
7085 init_numa_sched_groups_power(d
.sched_group_nodes
[i
]);
7087 if (d
.sd_allnodes
) {
7088 struct sched_group
*sg
;
7090 cpu_to_allnodes_group(cpumask_first(cpu_map
), cpu_map
, &sg
,
7092 init_numa_sched_groups_power(sg
);
7096 /* Attach the domains */
7097 for_each_cpu(i
, cpu_map
) {
7098 #ifdef CONFIG_SCHED_SMT
7099 sd
= &per_cpu(cpu_domains
, i
).sd
;
7100 #elif defined(CONFIG_SCHED_MC)
7101 sd
= &per_cpu(core_domains
, i
).sd
;
7103 sd
= &per_cpu(phys_domains
, i
).sd
;
7105 cpu_attach_domain(sd
, d
.rd
, i
);
7108 d
.sched_group_nodes
= NULL
; /* don't free this we still need it */
7109 __free_domain_allocs(&d
, sa_tmpmask
, cpu_map
);
7113 __free_domain_allocs(&d
, alloc_state
, cpu_map
);
7117 static int build_sched_domains(const struct cpumask
*cpu_map
)
7119 return __build_sched_domains(cpu_map
, NULL
);
7122 static cpumask_var_t
*doms_cur
; /* current sched domains */
7123 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7124 static struct sched_domain_attr
*dattr_cur
;
7125 /* attribues of custom domains in 'doms_cur' */
7128 * Special case: If a kmalloc of a doms_cur partition (array of
7129 * cpumask) fails, then fallback to a single sched domain,
7130 * as determined by the single cpumask fallback_doms.
7132 static cpumask_var_t fallback_doms
;
7135 * arch_update_cpu_topology lets virtualized architectures update the
7136 * cpu core maps. It is supposed to return 1 if the topology changed
7137 * or 0 if it stayed the same.
7139 int __attribute__((weak
)) arch_update_cpu_topology(void)
7144 cpumask_var_t
*alloc_sched_domains(unsigned int ndoms
)
7147 cpumask_var_t
*doms
;
7149 doms
= kmalloc(sizeof(*doms
) * ndoms
, GFP_KERNEL
);
7152 for (i
= 0; i
< ndoms
; i
++) {
7153 if (!alloc_cpumask_var(&doms
[i
], GFP_KERNEL
)) {
7154 free_sched_domains(doms
, i
);
7161 void free_sched_domains(cpumask_var_t doms
[], unsigned int ndoms
)
7164 for (i
= 0; i
< ndoms
; i
++)
7165 free_cpumask_var(doms
[i
]);
7170 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7171 * For now this just excludes isolated cpus, but could be used to
7172 * exclude other special cases in the future.
7174 static int arch_init_sched_domains(const struct cpumask
*cpu_map
)
7178 arch_update_cpu_topology();
7180 doms_cur
= alloc_sched_domains(ndoms_cur
);
7182 doms_cur
= &fallback_doms
;
7183 cpumask_andnot(doms_cur
[0], cpu_map
, cpu_isolated_map
);
7185 err
= build_sched_domains(doms_cur
[0]);
7186 register_sched_domain_sysctl();
7191 static void arch_destroy_sched_domains(const struct cpumask
*cpu_map
,
7192 struct cpumask
*tmpmask
)
7194 free_sched_groups(cpu_map
, tmpmask
);
7198 * Detach sched domains from a group of cpus specified in cpu_map
7199 * These cpus will now be attached to the NULL domain
7201 static void detach_destroy_domains(const struct cpumask
*cpu_map
)
7203 /* Save because hotplug lock held. */
7204 static DECLARE_BITMAP(tmpmask
, CONFIG_NR_CPUS
);
7207 for_each_cpu(i
, cpu_map
)
7208 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7209 synchronize_sched();
7210 arch_destroy_sched_domains(cpu_map
, to_cpumask(tmpmask
));
7213 /* handle null as "default" */
7214 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7215 struct sched_domain_attr
*new, int idx_new
)
7217 struct sched_domain_attr tmp
;
7224 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7225 new ? (new + idx_new
) : &tmp
,
7226 sizeof(struct sched_domain_attr
));
7230 * Partition sched domains as specified by the 'ndoms_new'
7231 * cpumasks in the array doms_new[] of cpumasks. This compares
7232 * doms_new[] to the current sched domain partitioning, doms_cur[].
7233 * It destroys each deleted domain and builds each new domain.
7235 * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
7236 * The masks don't intersect (don't overlap.) We should setup one
7237 * sched domain for each mask. CPUs not in any of the cpumasks will
7238 * not be load balanced. If the same cpumask appears both in the
7239 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7242 * The passed in 'doms_new' should be allocated using
7243 * alloc_sched_domains. This routine takes ownership of it and will
7244 * free_sched_domains it when done with it. If the caller failed the
7245 * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
7246 * and partition_sched_domains() will fallback to the single partition
7247 * 'fallback_doms', it also forces the domains to be rebuilt.
7249 * If doms_new == NULL it will be replaced with cpu_online_mask.
7250 * ndoms_new == 0 is a special case for destroying existing domains,
7251 * and it will not create the default domain.
7253 * Call with hotplug lock held
7255 void partition_sched_domains(int ndoms_new
, cpumask_var_t doms_new
[],
7256 struct sched_domain_attr
*dattr_new
)
7261 mutex_lock(&sched_domains_mutex
);
7263 /* always unregister in case we don't destroy any domains */
7264 unregister_sched_domain_sysctl();
7266 /* Let architecture update cpu core mappings. */
7267 new_topology
= arch_update_cpu_topology();
7269 n
= doms_new
? ndoms_new
: 0;
7271 /* Destroy deleted domains */
7272 for (i
= 0; i
< ndoms_cur
; i
++) {
7273 for (j
= 0; j
< n
&& !new_topology
; j
++) {
7274 if (cpumask_equal(doms_cur
[i
], doms_new
[j
])
7275 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7278 /* no match - a current sched domain not in new doms_new[] */
7279 detach_destroy_domains(doms_cur
[i
]);
7284 if (doms_new
== NULL
) {
7286 doms_new
= &fallback_doms
;
7287 cpumask_andnot(doms_new
[0], cpu_active_mask
, cpu_isolated_map
);
7288 WARN_ON_ONCE(dattr_new
);
7291 /* Build new domains */
7292 for (i
= 0; i
< ndoms_new
; i
++) {
7293 for (j
= 0; j
< ndoms_cur
&& !new_topology
; j
++) {
7294 if (cpumask_equal(doms_new
[i
], doms_cur
[j
])
7295 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7298 /* no match - add a new doms_new */
7299 __build_sched_domains(doms_new
[i
],
7300 dattr_new
? dattr_new
+ i
: NULL
);
7305 /* Remember the new sched domains */
7306 if (doms_cur
!= &fallback_doms
)
7307 free_sched_domains(doms_cur
, ndoms_cur
);
7308 kfree(dattr_cur
); /* kfree(NULL) is safe */
7309 doms_cur
= doms_new
;
7310 dattr_cur
= dattr_new
;
7311 ndoms_cur
= ndoms_new
;
7313 register_sched_domain_sysctl();
7315 mutex_unlock(&sched_domains_mutex
);
7318 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7319 static void arch_reinit_sched_domains(void)
7323 /* Destroy domains first to force the rebuild */
7324 partition_sched_domains(0, NULL
, NULL
);
7326 rebuild_sched_domains();
7330 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7332 unsigned int level
= 0;
7334 if (sscanf(buf
, "%u", &level
) != 1)
7338 * level is always be positive so don't check for
7339 * level < POWERSAVINGS_BALANCE_NONE which is 0
7340 * What happens on 0 or 1 byte write,
7341 * need to check for count as well?
7344 if (level
>= MAX_POWERSAVINGS_BALANCE_LEVELS
)
7348 sched_smt_power_savings
= level
;
7350 sched_mc_power_savings
= level
;
7352 arch_reinit_sched_domains();
7357 #ifdef CONFIG_SCHED_MC
7358 static ssize_t
sched_mc_power_savings_show(struct sysdev_class
*class,
7361 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7363 static ssize_t
sched_mc_power_savings_store(struct sysdev_class
*class,
7364 const char *buf
, size_t count
)
7366 return sched_power_savings_store(buf
, count
, 0);
7368 static SYSDEV_CLASS_ATTR(sched_mc_power_savings
, 0644,
7369 sched_mc_power_savings_show
,
7370 sched_mc_power_savings_store
);
7373 #ifdef CONFIG_SCHED_SMT
7374 static ssize_t
sched_smt_power_savings_show(struct sysdev_class
*dev
,
7377 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7379 static ssize_t
sched_smt_power_savings_store(struct sysdev_class
*dev
,
7380 const char *buf
, size_t count
)
7382 return sched_power_savings_store(buf
, count
, 1);
7384 static SYSDEV_CLASS_ATTR(sched_smt_power_savings
, 0644,
7385 sched_smt_power_savings_show
,
7386 sched_smt_power_savings_store
);
7389 int __init
sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7393 #ifdef CONFIG_SCHED_SMT
7395 err
= sysfs_create_file(&cls
->kset
.kobj
,
7396 &attr_sched_smt_power_savings
.attr
);
7398 #ifdef CONFIG_SCHED_MC
7399 if (!err
&& mc_capable())
7400 err
= sysfs_create_file(&cls
->kset
.kobj
,
7401 &attr_sched_mc_power_savings
.attr
);
7405 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
7407 #ifndef CONFIG_CPUSETS
7409 * Add online and remove offline CPUs from the scheduler domains.
7410 * When cpusets are enabled they take over this function.
7412 static int update_sched_domains(struct notifier_block
*nfb
,
7413 unsigned long action
, void *hcpu
)
7417 case CPU_ONLINE_FROZEN
:
7418 case CPU_DOWN_PREPARE
:
7419 case CPU_DOWN_PREPARE_FROZEN
:
7420 case CPU_DOWN_FAILED
:
7421 case CPU_DOWN_FAILED_FROZEN
:
7422 partition_sched_domains(1, NULL
, NULL
);
7431 static int update_runtime(struct notifier_block
*nfb
,
7432 unsigned long action
, void *hcpu
)
7434 int cpu
= (int)(long)hcpu
;
7437 case CPU_DOWN_PREPARE
:
7438 case CPU_DOWN_PREPARE_FROZEN
:
7439 disable_runtime(cpu_rq(cpu
));
7442 case CPU_DOWN_FAILED
:
7443 case CPU_DOWN_FAILED_FROZEN
:
7445 case CPU_ONLINE_FROZEN
:
7446 enable_runtime(cpu_rq(cpu
));
7454 void __init
sched_init_smp(void)
7456 cpumask_var_t non_isolated_cpus
;
7458 alloc_cpumask_var(&non_isolated_cpus
, GFP_KERNEL
);
7459 alloc_cpumask_var(&fallback_doms
, GFP_KERNEL
);
7461 #if defined(CONFIG_NUMA)
7462 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7464 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7467 mutex_lock(&sched_domains_mutex
);
7468 arch_init_sched_domains(cpu_active_mask
);
7469 cpumask_andnot(non_isolated_cpus
, cpu_possible_mask
, cpu_isolated_map
);
7470 if (cpumask_empty(non_isolated_cpus
))
7471 cpumask_set_cpu(smp_processor_id(), non_isolated_cpus
);
7472 mutex_unlock(&sched_domains_mutex
);
7475 #ifndef CONFIG_CPUSETS
7476 /* XXX: Theoretical race here - CPU may be hotplugged now */
7477 hotcpu_notifier(update_sched_domains
, 0);
7480 /* RT runtime code needs to handle some hotplug events */
7481 hotcpu_notifier(update_runtime
, 0);
7485 /* Move init over to a non-isolated CPU */
7486 if (set_cpus_allowed_ptr(current
, non_isolated_cpus
) < 0)
7488 sched_init_granularity();
7489 free_cpumask_var(non_isolated_cpus
);
7491 init_sched_rt_class();
7494 void __init
sched_init_smp(void)
7496 sched_init_granularity();
7498 #endif /* CONFIG_SMP */
7500 const_debug
unsigned int sysctl_timer_migration
= 1;
7502 int in_sched_functions(unsigned long addr
)
7504 return in_lock_functions(addr
) ||
7505 (addr
>= (unsigned long)__sched_text_start
7506 && addr
< (unsigned long)__sched_text_end
);
7509 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7511 cfs_rq
->tasks_timeline
= RB_ROOT
;
7512 INIT_LIST_HEAD(&cfs_rq
->tasks
);
7513 #ifdef CONFIG_FAIR_GROUP_SCHED
7516 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7519 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7521 struct rt_prio_array
*array
;
7524 array
= &rt_rq
->active
;
7525 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7526 INIT_LIST_HEAD(array
->queue
+ i
);
7527 __clear_bit(i
, array
->bitmap
);
7529 /* delimiter for bitsearch: */
7530 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7532 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7533 rt_rq
->highest_prio
.curr
= MAX_RT_PRIO
;
7535 rt_rq
->highest_prio
.next
= MAX_RT_PRIO
;
7539 rt_rq
->rt_nr_migratory
= 0;
7540 rt_rq
->overloaded
= 0;
7541 plist_head_init_raw(&rt_rq
->pushable_tasks
, &rq
->lock
);
7545 rt_rq
->rt_throttled
= 0;
7546 rt_rq
->rt_runtime
= 0;
7547 raw_spin_lock_init(&rt_rq
->rt_runtime_lock
);
7549 #ifdef CONFIG_RT_GROUP_SCHED
7550 rt_rq
->rt_nr_boosted
= 0;
7555 #ifdef CONFIG_FAIR_GROUP_SCHED
7556 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7557 struct sched_entity
*se
, int cpu
, int add
,
7558 struct sched_entity
*parent
)
7560 struct rq
*rq
= cpu_rq(cpu
);
7561 tg
->cfs_rq
[cpu
] = cfs_rq
;
7562 init_cfs_rq(cfs_rq
, rq
);
7565 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7568 /* se could be NULL for init_task_group */
7573 se
->cfs_rq
= &rq
->cfs
;
7575 se
->cfs_rq
= parent
->my_q
;
7578 se
->load
.weight
= tg
->shares
;
7579 se
->load
.inv_weight
= 0;
7580 se
->parent
= parent
;
7584 #ifdef CONFIG_RT_GROUP_SCHED
7585 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7586 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
7587 struct sched_rt_entity
*parent
)
7589 struct rq
*rq
= cpu_rq(cpu
);
7591 tg
->rt_rq
[cpu
] = rt_rq
;
7592 init_rt_rq(rt_rq
, rq
);
7594 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7596 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7598 tg
->rt_se
[cpu
] = rt_se
;
7603 rt_se
->rt_rq
= &rq
->rt
;
7605 rt_se
->rt_rq
= parent
->my_q
;
7607 rt_se
->my_q
= rt_rq
;
7608 rt_se
->parent
= parent
;
7609 INIT_LIST_HEAD(&rt_se
->run_list
);
7613 void __init
sched_init(void)
7616 unsigned long alloc_size
= 0, ptr
;
7618 #ifdef CONFIG_FAIR_GROUP_SCHED
7619 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7621 #ifdef CONFIG_RT_GROUP_SCHED
7622 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7624 #ifdef CONFIG_CPUMASK_OFFSTACK
7625 alloc_size
+= num_possible_cpus() * cpumask_size();
7628 ptr
= (unsigned long)kzalloc(alloc_size
, GFP_NOWAIT
);
7630 #ifdef CONFIG_FAIR_GROUP_SCHED
7631 init_task_group
.se
= (struct sched_entity
**)ptr
;
7632 ptr
+= nr_cpu_ids
* sizeof(void **);
7634 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7635 ptr
+= nr_cpu_ids
* sizeof(void **);
7637 #endif /* CONFIG_FAIR_GROUP_SCHED */
7638 #ifdef CONFIG_RT_GROUP_SCHED
7639 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7640 ptr
+= nr_cpu_ids
* sizeof(void **);
7642 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7643 ptr
+= nr_cpu_ids
* sizeof(void **);
7645 #endif /* CONFIG_RT_GROUP_SCHED */
7646 #ifdef CONFIG_CPUMASK_OFFSTACK
7647 for_each_possible_cpu(i
) {
7648 per_cpu(load_balance_tmpmask
, i
) = (void *)ptr
;
7649 ptr
+= cpumask_size();
7651 #endif /* CONFIG_CPUMASK_OFFSTACK */
7655 init_defrootdomain();
7658 init_rt_bandwidth(&def_rt_bandwidth
,
7659 global_rt_period(), global_rt_runtime());
7661 #ifdef CONFIG_RT_GROUP_SCHED
7662 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7663 global_rt_period(), global_rt_runtime());
7664 #endif /* CONFIG_RT_GROUP_SCHED */
7666 #ifdef CONFIG_CGROUP_SCHED
7667 list_add(&init_task_group
.list
, &task_groups
);
7668 INIT_LIST_HEAD(&init_task_group
.children
);
7670 #endif /* CONFIG_CGROUP_SCHED */
7672 #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
7673 update_shares_data
= __alloc_percpu(nr_cpu_ids
* sizeof(unsigned long),
7674 __alignof__(unsigned long));
7676 for_each_possible_cpu(i
) {
7680 raw_spin_lock_init(&rq
->lock
);
7682 rq
->calc_load_active
= 0;
7683 rq
->calc_load_update
= jiffies
+ LOAD_FREQ
;
7684 init_cfs_rq(&rq
->cfs
, rq
);
7685 init_rt_rq(&rq
->rt
, rq
);
7686 #ifdef CONFIG_FAIR_GROUP_SCHED
7687 init_task_group
.shares
= init_task_group_load
;
7688 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7689 #ifdef CONFIG_CGROUP_SCHED
7691 * How much cpu bandwidth does init_task_group get?
7693 * In case of task-groups formed thr' the cgroup filesystem, it
7694 * gets 100% of the cpu resources in the system. This overall
7695 * system cpu resource is divided among the tasks of
7696 * init_task_group and its child task-groups in a fair manner,
7697 * based on each entity's (task or task-group's) weight
7698 * (se->load.weight).
7700 * In other words, if init_task_group has 10 tasks of weight
7701 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7702 * then A0's share of the cpu resource is:
7704 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7706 * We achieve this by letting init_task_group's tasks sit
7707 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7709 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
7711 #endif /* CONFIG_FAIR_GROUP_SCHED */
7713 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7714 #ifdef CONFIG_RT_GROUP_SCHED
7715 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7716 #ifdef CONFIG_CGROUP_SCHED
7717 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
7721 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7722 rq
->cpu_load
[j
] = 0;
7726 rq
->post_schedule
= 0;
7727 rq
->active_balance
= 0;
7728 rq
->next_balance
= jiffies
;
7732 rq
->migration_thread
= NULL
;
7734 rq
->avg_idle
= 2*sysctl_sched_migration_cost
;
7735 INIT_LIST_HEAD(&rq
->migration_queue
);
7736 rq_attach_root(rq
, &def_root_domain
);
7739 atomic_set(&rq
->nr_iowait
, 0);
7742 set_load_weight(&init_task
);
7744 #ifdef CONFIG_PREEMPT_NOTIFIERS
7745 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7749 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
);
7752 #ifdef CONFIG_RT_MUTEXES
7753 plist_head_init_raw(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7757 * The boot idle thread does lazy MMU switching as well:
7759 atomic_inc(&init_mm
.mm_count
);
7760 enter_lazy_tlb(&init_mm
, current
);
7763 * Make us the idle thread. Technically, schedule() should not be
7764 * called from this thread, however somewhere below it might be,
7765 * but because we are the idle thread, we just pick up running again
7766 * when this runqueue becomes "idle".
7768 init_idle(current
, smp_processor_id());
7770 calc_load_update
= jiffies
+ LOAD_FREQ
;
7773 * During early bootup we pretend to be a normal task:
7775 current
->sched_class
= &fair_sched_class
;
7777 /* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
7778 zalloc_cpumask_var(&nohz_cpu_mask
, GFP_NOWAIT
);
7781 zalloc_cpumask_var(&nohz
.cpu_mask
, GFP_NOWAIT
);
7782 alloc_cpumask_var(&nohz
.ilb_grp_nohz_mask
, GFP_NOWAIT
);
7784 /* May be allocated at isolcpus cmdline parse time */
7785 if (cpu_isolated_map
== NULL
)
7786 zalloc_cpumask_var(&cpu_isolated_map
, GFP_NOWAIT
);
7791 scheduler_running
= 1;
7794 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7795 static inline int preempt_count_equals(int preempt_offset
)
7797 int nested
= (preempt_count() & ~PREEMPT_ACTIVE
) + rcu_preempt_depth();
7799 return (nested
== PREEMPT_INATOMIC_BASE
+ preempt_offset
);
7802 void __might_sleep(const char *file
, int line
, int preempt_offset
)
7805 static unsigned long prev_jiffy
; /* ratelimiting */
7807 if ((preempt_count_equals(preempt_offset
) && !irqs_disabled()) ||
7808 system_state
!= SYSTEM_RUNNING
|| oops_in_progress
)
7810 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7812 prev_jiffy
= jiffies
;
7815 "BUG: sleeping function called from invalid context at %s:%d\n",
7818 "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
7819 in_atomic(), irqs_disabled(),
7820 current
->pid
, current
->comm
);
7822 debug_show_held_locks(current
);
7823 if (irqs_disabled())
7824 print_irqtrace_events(current
);
7828 EXPORT_SYMBOL(__might_sleep
);
7831 #ifdef CONFIG_MAGIC_SYSRQ
7832 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7836 update_rq_clock(rq
);
7837 on_rq
= p
->se
.on_rq
;
7839 deactivate_task(rq
, p
, 0);
7840 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7842 activate_task(rq
, p
, 0);
7843 resched_task(rq
->curr
);
7847 void normalize_rt_tasks(void)
7849 struct task_struct
*g
, *p
;
7850 unsigned long flags
;
7853 read_lock_irqsave(&tasklist_lock
, flags
);
7854 do_each_thread(g
, p
) {
7856 * Only normalize user tasks:
7861 p
->se
.exec_start
= 0;
7862 #ifdef CONFIG_SCHEDSTATS
7863 p
->se
.wait_start
= 0;
7864 p
->se
.sleep_start
= 0;
7865 p
->se
.block_start
= 0;
7870 * Renice negative nice level userspace
7873 if (TASK_NICE(p
) < 0 && p
->mm
)
7874 set_user_nice(p
, 0);
7878 raw_spin_lock(&p
->pi_lock
);
7879 rq
= __task_rq_lock(p
);
7881 normalize_task(rq
, p
);
7883 __task_rq_unlock(rq
);
7884 raw_spin_unlock(&p
->pi_lock
);
7885 } while_each_thread(g
, p
);
7887 read_unlock_irqrestore(&tasklist_lock
, flags
);
7890 #endif /* CONFIG_MAGIC_SYSRQ */
7894 * These functions are only useful for the IA64 MCA handling.
7896 * They can only be called when the whole system has been
7897 * stopped - every CPU needs to be quiescent, and no scheduling
7898 * activity can take place. Using them for anything else would
7899 * be a serious bug, and as a result, they aren't even visible
7900 * under any other configuration.
7904 * curr_task - return the current task for a given cpu.
7905 * @cpu: the processor in question.
7907 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7909 struct task_struct
*curr_task(int cpu
)
7911 return cpu_curr(cpu
);
7915 * set_curr_task - set the current task for a given cpu.
7916 * @cpu: the processor in question.
7917 * @p: the task pointer to set.
7919 * Description: This function must only be used when non-maskable interrupts
7920 * are serviced on a separate stack. It allows the architecture to switch the
7921 * notion of the current task on a cpu in a non-blocking manner. This function
7922 * must be called with all CPU's synchronized, and interrupts disabled, the
7923 * and caller must save the original value of the current task (see
7924 * curr_task() above) and restore that value before reenabling interrupts and
7925 * re-starting the system.
7927 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7929 void set_curr_task(int cpu
, struct task_struct
*p
)
7936 #ifdef CONFIG_FAIR_GROUP_SCHED
7937 static void free_fair_sched_group(struct task_group
*tg
)
7941 for_each_possible_cpu(i
) {
7943 kfree(tg
->cfs_rq
[i
]);
7953 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
7955 struct cfs_rq
*cfs_rq
;
7956 struct sched_entity
*se
;
7960 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
7963 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
7967 tg
->shares
= NICE_0_LOAD
;
7969 for_each_possible_cpu(i
) {
7972 cfs_rq
= kzalloc_node(sizeof(struct cfs_rq
),
7973 GFP_KERNEL
, cpu_to_node(i
));
7977 se
= kzalloc_node(sizeof(struct sched_entity
),
7978 GFP_KERNEL
, cpu_to_node(i
));
7982 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent
->se
[i
]);
7993 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
7995 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
7996 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
7999 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8001 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
8003 #else /* !CONFG_FAIR_GROUP_SCHED */
8004 static inline void free_fair_sched_group(struct task_group
*tg
)
8009 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8014 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8018 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8021 #endif /* CONFIG_FAIR_GROUP_SCHED */
8023 #ifdef CONFIG_RT_GROUP_SCHED
8024 static void free_rt_sched_group(struct task_group
*tg
)
8028 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8030 for_each_possible_cpu(i
) {
8032 kfree(tg
->rt_rq
[i
]);
8034 kfree(tg
->rt_se
[i
]);
8042 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8044 struct rt_rq
*rt_rq
;
8045 struct sched_rt_entity
*rt_se
;
8049 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8052 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8056 init_rt_bandwidth(&tg
->rt_bandwidth
,
8057 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8059 for_each_possible_cpu(i
) {
8062 rt_rq
= kzalloc_node(sizeof(struct rt_rq
),
8063 GFP_KERNEL
, cpu_to_node(i
));
8067 rt_se
= kzalloc_node(sizeof(struct sched_rt_entity
),
8068 GFP_KERNEL
, cpu_to_node(i
));
8072 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent
->rt_se
[i
]);
8083 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8085 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
8086 &cpu_rq(cpu
)->leaf_rt_rq_list
);
8089 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8091 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
8093 #else /* !CONFIG_RT_GROUP_SCHED */
8094 static inline void free_rt_sched_group(struct task_group
*tg
)
8099 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8104 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8108 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8111 #endif /* CONFIG_RT_GROUP_SCHED */
8113 #ifdef CONFIG_CGROUP_SCHED
8114 static void free_sched_group(struct task_group
*tg
)
8116 free_fair_sched_group(tg
);
8117 free_rt_sched_group(tg
);
8121 /* allocate runqueue etc for a new task group */
8122 struct task_group
*sched_create_group(struct task_group
*parent
)
8124 struct task_group
*tg
;
8125 unsigned long flags
;
8128 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8130 return ERR_PTR(-ENOMEM
);
8132 if (!alloc_fair_sched_group(tg
, parent
))
8135 if (!alloc_rt_sched_group(tg
, parent
))
8138 spin_lock_irqsave(&task_group_lock
, flags
);
8139 for_each_possible_cpu(i
) {
8140 register_fair_sched_group(tg
, i
);
8141 register_rt_sched_group(tg
, i
);
8143 list_add_rcu(&tg
->list
, &task_groups
);
8145 WARN_ON(!parent
); /* root should already exist */
8147 tg
->parent
= parent
;
8148 INIT_LIST_HEAD(&tg
->children
);
8149 list_add_rcu(&tg
->siblings
, &parent
->children
);
8150 spin_unlock_irqrestore(&task_group_lock
, flags
);
8155 free_sched_group(tg
);
8156 return ERR_PTR(-ENOMEM
);
8159 /* rcu callback to free various structures associated with a task group */
8160 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8162 /* now it should be safe to free those cfs_rqs */
8163 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8166 /* Destroy runqueue etc associated with a task group */
8167 void sched_destroy_group(struct task_group
*tg
)
8169 unsigned long flags
;
8172 spin_lock_irqsave(&task_group_lock
, flags
);
8173 for_each_possible_cpu(i
) {
8174 unregister_fair_sched_group(tg
, i
);
8175 unregister_rt_sched_group(tg
, i
);
8177 list_del_rcu(&tg
->list
);
8178 list_del_rcu(&tg
->siblings
);
8179 spin_unlock_irqrestore(&task_group_lock
, flags
);
8181 /* wait for possible concurrent references to cfs_rqs complete */
8182 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8185 /* change task's runqueue when it moves between groups.
8186 * The caller of this function should have put the task in its new group
8187 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8188 * reflect its new group.
8190 void sched_move_task(struct task_struct
*tsk
)
8193 unsigned long flags
;
8196 rq
= task_rq_lock(tsk
, &flags
);
8198 update_rq_clock(rq
);
8200 running
= task_current(rq
, tsk
);
8201 on_rq
= tsk
->se
.on_rq
;
8204 dequeue_task(rq
, tsk
, 0);
8205 if (unlikely(running
))
8206 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8208 set_task_rq(tsk
, task_cpu(tsk
));
8210 #ifdef CONFIG_FAIR_GROUP_SCHED
8211 if (tsk
->sched_class
->moved_group
)
8212 tsk
->sched_class
->moved_group(tsk
, on_rq
);
8215 if (unlikely(running
))
8216 tsk
->sched_class
->set_curr_task(rq
);
8218 enqueue_task(rq
, tsk
, 0, false);
8220 task_rq_unlock(rq
, &flags
);
8222 #endif /* CONFIG_CGROUP_SCHED */
8224 #ifdef CONFIG_FAIR_GROUP_SCHED
8225 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8227 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8232 dequeue_entity(cfs_rq
, se
, 0);
8234 se
->load
.weight
= shares
;
8235 se
->load
.inv_weight
= 0;
8238 enqueue_entity(cfs_rq
, se
, 0);
8241 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8243 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8244 struct rq
*rq
= cfs_rq
->rq
;
8245 unsigned long flags
;
8247 raw_spin_lock_irqsave(&rq
->lock
, flags
);
8248 __set_se_shares(se
, shares
);
8249 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
8252 static DEFINE_MUTEX(shares_mutex
);
8254 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8257 unsigned long flags
;
8260 * We can't change the weight of the root cgroup.
8265 if (shares
< MIN_SHARES
)
8266 shares
= MIN_SHARES
;
8267 else if (shares
> MAX_SHARES
)
8268 shares
= MAX_SHARES
;
8270 mutex_lock(&shares_mutex
);
8271 if (tg
->shares
== shares
)
8274 spin_lock_irqsave(&task_group_lock
, flags
);
8275 for_each_possible_cpu(i
)
8276 unregister_fair_sched_group(tg
, i
);
8277 list_del_rcu(&tg
->siblings
);
8278 spin_unlock_irqrestore(&task_group_lock
, flags
);
8280 /* wait for any ongoing reference to this group to finish */
8281 synchronize_sched();
8284 * Now we are free to modify the group's share on each cpu
8285 * w/o tripping rebalance_share or load_balance_fair.
8287 tg
->shares
= shares
;
8288 for_each_possible_cpu(i
) {
8292 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
8293 set_se_shares(tg
->se
[i
], shares
);
8297 * Enable load balance activity on this group, by inserting it back on
8298 * each cpu's rq->leaf_cfs_rq_list.
8300 spin_lock_irqsave(&task_group_lock
, flags
);
8301 for_each_possible_cpu(i
)
8302 register_fair_sched_group(tg
, i
);
8303 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
8304 spin_unlock_irqrestore(&task_group_lock
, flags
);
8306 mutex_unlock(&shares_mutex
);
8310 unsigned long sched_group_shares(struct task_group
*tg
)
8316 #ifdef CONFIG_RT_GROUP_SCHED
8318 * Ensure that the real time constraints are schedulable.
8320 static DEFINE_MUTEX(rt_constraints_mutex
);
8322 static unsigned long to_ratio(u64 period
, u64 runtime
)
8324 if (runtime
== RUNTIME_INF
)
8327 return div64_u64(runtime
<< 20, period
);
8330 /* Must be called with tasklist_lock held */
8331 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8333 struct task_struct
*g
, *p
;
8335 do_each_thread(g
, p
) {
8336 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8338 } while_each_thread(g
, p
);
8343 struct rt_schedulable_data
{
8344 struct task_group
*tg
;
8349 static int tg_schedulable(struct task_group
*tg
, void *data
)
8351 struct rt_schedulable_data
*d
= data
;
8352 struct task_group
*child
;
8353 unsigned long total
, sum
= 0;
8354 u64 period
, runtime
;
8356 period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8357 runtime
= tg
->rt_bandwidth
.rt_runtime
;
8360 period
= d
->rt_period
;
8361 runtime
= d
->rt_runtime
;
8365 * Cannot have more runtime than the period.
8367 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8371 * Ensure we don't starve existing RT tasks.
8373 if (rt_bandwidth_enabled() && !runtime
&& tg_has_rt_tasks(tg
))
8376 total
= to_ratio(period
, runtime
);
8379 * Nobody can have more than the global setting allows.
8381 if (total
> to_ratio(global_rt_period(), global_rt_runtime()))
8385 * The sum of our children's runtime should not exceed our own.
8387 list_for_each_entry_rcu(child
, &tg
->children
, siblings
) {
8388 period
= ktime_to_ns(child
->rt_bandwidth
.rt_period
);
8389 runtime
= child
->rt_bandwidth
.rt_runtime
;
8391 if (child
== d
->tg
) {
8392 period
= d
->rt_period
;
8393 runtime
= d
->rt_runtime
;
8396 sum
+= to_ratio(period
, runtime
);
8405 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8407 struct rt_schedulable_data data
= {
8409 .rt_period
= period
,
8410 .rt_runtime
= runtime
,
8413 return walk_tg_tree(tg_schedulable
, tg_nop
, &data
);
8416 static int tg_set_bandwidth(struct task_group
*tg
,
8417 u64 rt_period
, u64 rt_runtime
)
8421 mutex_lock(&rt_constraints_mutex
);
8422 read_lock(&tasklist_lock
);
8423 err
= __rt_schedulable(tg
, rt_period
, rt_runtime
);
8427 raw_spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8428 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8429 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8431 for_each_possible_cpu(i
) {
8432 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8434 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8435 rt_rq
->rt_runtime
= rt_runtime
;
8436 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8438 raw_spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8440 read_unlock(&tasklist_lock
);
8441 mutex_unlock(&rt_constraints_mutex
);
8446 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8448 u64 rt_runtime
, rt_period
;
8450 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8451 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8452 if (rt_runtime_us
< 0)
8453 rt_runtime
= RUNTIME_INF
;
8455 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8458 long sched_group_rt_runtime(struct task_group
*tg
)
8462 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8465 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8466 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8467 return rt_runtime_us
;
8470 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8472 u64 rt_runtime
, rt_period
;
8474 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8475 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8480 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8483 long sched_group_rt_period(struct task_group
*tg
)
8487 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8488 do_div(rt_period_us
, NSEC_PER_USEC
);
8489 return rt_period_us
;
8492 static int sched_rt_global_constraints(void)
8494 u64 runtime
, period
;
8497 if (sysctl_sched_rt_period
<= 0)
8500 runtime
= global_rt_runtime();
8501 period
= global_rt_period();
8504 * Sanity check on the sysctl variables.
8506 if (runtime
> period
&& runtime
!= RUNTIME_INF
)
8509 mutex_lock(&rt_constraints_mutex
);
8510 read_lock(&tasklist_lock
);
8511 ret
= __rt_schedulable(NULL
, 0, 0);
8512 read_unlock(&tasklist_lock
);
8513 mutex_unlock(&rt_constraints_mutex
);
8518 int sched_rt_can_attach(struct task_group
*tg
, struct task_struct
*tsk
)
8520 /* Don't accept realtime tasks when there is no way for them to run */
8521 if (rt_task(tsk
) && tg
->rt_bandwidth
.rt_runtime
== 0)
8527 #else /* !CONFIG_RT_GROUP_SCHED */
8528 static int sched_rt_global_constraints(void)
8530 unsigned long flags
;
8533 if (sysctl_sched_rt_period
<= 0)
8537 * There's always some RT tasks in the root group
8538 * -- migration, kstopmachine etc..
8540 if (sysctl_sched_rt_runtime
== 0)
8543 raw_spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8544 for_each_possible_cpu(i
) {
8545 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8547 raw_spin_lock(&rt_rq
->rt_runtime_lock
);
8548 rt_rq
->rt_runtime
= global_rt_runtime();
8549 raw_spin_unlock(&rt_rq
->rt_runtime_lock
);
8551 raw_spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8555 #endif /* CONFIG_RT_GROUP_SCHED */
8557 int sched_rt_handler(struct ctl_table
*table
, int write
,
8558 void __user
*buffer
, size_t *lenp
,
8562 int old_period
, old_runtime
;
8563 static DEFINE_MUTEX(mutex
);
8566 old_period
= sysctl_sched_rt_period
;
8567 old_runtime
= sysctl_sched_rt_runtime
;
8569 ret
= proc_dointvec(table
, write
, buffer
, lenp
, ppos
);
8571 if (!ret
&& write
) {
8572 ret
= sched_rt_global_constraints();
8574 sysctl_sched_rt_period
= old_period
;
8575 sysctl_sched_rt_runtime
= old_runtime
;
8577 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8578 def_rt_bandwidth
.rt_period
=
8579 ns_to_ktime(global_rt_period());
8582 mutex_unlock(&mutex
);
8587 #ifdef CONFIG_CGROUP_SCHED
8589 /* return corresponding task_group object of a cgroup */
8590 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8592 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8593 struct task_group
, css
);
8596 static struct cgroup_subsys_state
*
8597 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8599 struct task_group
*tg
, *parent
;
8601 if (!cgrp
->parent
) {
8602 /* This is early initialization for the top cgroup */
8603 return &init_task_group
.css
;
8606 parent
= cgroup_tg(cgrp
->parent
);
8607 tg
= sched_create_group(parent
);
8609 return ERR_PTR(-ENOMEM
);
8615 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8617 struct task_group
*tg
= cgroup_tg(cgrp
);
8619 sched_destroy_group(tg
);
8623 cpu_cgroup_can_attach_task(struct cgroup
*cgrp
, struct task_struct
*tsk
)
8625 #ifdef CONFIG_RT_GROUP_SCHED
8626 if (!sched_rt_can_attach(cgroup_tg(cgrp
), tsk
))
8629 /* We don't support RT-tasks being in separate groups */
8630 if (tsk
->sched_class
!= &fair_sched_class
)
8637 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8638 struct task_struct
*tsk
, bool threadgroup
)
8640 int retval
= cpu_cgroup_can_attach_task(cgrp
, tsk
);
8644 struct task_struct
*c
;
8646 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
8647 retval
= cpu_cgroup_can_attach_task(cgrp
, c
);
8659 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8660 struct cgroup
*old_cont
, struct task_struct
*tsk
,
8663 sched_move_task(tsk
);
8665 struct task_struct
*c
;
8667 list_for_each_entry_rcu(c
, &tsk
->thread_group
, thread_group
) {
8674 #ifdef CONFIG_FAIR_GROUP_SCHED
8675 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
8678 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8681 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
8683 struct task_group
*tg
= cgroup_tg(cgrp
);
8685 return (u64
) tg
->shares
;
8687 #endif /* CONFIG_FAIR_GROUP_SCHED */
8689 #ifdef CONFIG_RT_GROUP_SCHED
8690 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8693 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8696 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8698 return sched_group_rt_runtime(cgroup_tg(cgrp
));
8701 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8704 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8707 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8709 return sched_group_rt_period(cgroup_tg(cgrp
));
8711 #endif /* CONFIG_RT_GROUP_SCHED */
8713 static struct cftype cpu_files
[] = {
8714 #ifdef CONFIG_FAIR_GROUP_SCHED
8717 .read_u64
= cpu_shares_read_u64
,
8718 .write_u64
= cpu_shares_write_u64
,
8721 #ifdef CONFIG_RT_GROUP_SCHED
8723 .name
= "rt_runtime_us",
8724 .read_s64
= cpu_rt_runtime_read
,
8725 .write_s64
= cpu_rt_runtime_write
,
8728 .name
= "rt_period_us",
8729 .read_u64
= cpu_rt_period_read_uint
,
8730 .write_u64
= cpu_rt_period_write_uint
,
8735 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8737 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8740 struct cgroup_subsys cpu_cgroup_subsys
= {
8742 .create
= cpu_cgroup_create
,
8743 .destroy
= cpu_cgroup_destroy
,
8744 .can_attach
= cpu_cgroup_can_attach
,
8745 .attach
= cpu_cgroup_attach
,
8746 .populate
= cpu_cgroup_populate
,
8747 .subsys_id
= cpu_cgroup_subsys_id
,
8751 #endif /* CONFIG_CGROUP_SCHED */
8753 #ifdef CONFIG_CGROUP_CPUACCT
8756 * CPU accounting code for task groups.
8758 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8759 * (balbir@in.ibm.com).
8762 /* track cpu usage of a group of tasks and its child groups */
8764 struct cgroup_subsys_state css
;
8765 /* cpuusage holds pointer to a u64-type object on every cpu */
8767 struct percpu_counter cpustat
[CPUACCT_STAT_NSTATS
];
8768 struct cpuacct
*parent
;
8771 struct cgroup_subsys cpuacct_subsys
;
8773 /* return cpu accounting group corresponding to this container */
8774 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8776 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8777 struct cpuacct
, css
);
8780 /* return cpu accounting group to which this task belongs */
8781 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8783 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8784 struct cpuacct
, css
);
8787 /* create a new cpu accounting group */
8788 static struct cgroup_subsys_state
*cpuacct_create(
8789 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8791 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8797 ca
->cpuusage
= alloc_percpu(u64
);
8801 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
8802 if (percpu_counter_init(&ca
->cpustat
[i
], 0))
8803 goto out_free_counters
;
8806 ca
->parent
= cgroup_ca(cgrp
->parent
);
8812 percpu_counter_destroy(&ca
->cpustat
[i
]);
8813 free_percpu(ca
->cpuusage
);
8817 return ERR_PTR(-ENOMEM
);
8820 /* destroy an existing cpu accounting group */
8822 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8824 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8827 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++)
8828 percpu_counter_destroy(&ca
->cpustat
[i
]);
8829 free_percpu(ca
->cpuusage
);
8833 static u64
cpuacct_cpuusage_read(struct cpuacct
*ca
, int cpu
)
8835 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8838 #ifndef CONFIG_64BIT
8840 * Take rq->lock to make 64-bit read safe on 32-bit platforms.
8842 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8844 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8852 static void cpuacct_cpuusage_write(struct cpuacct
*ca
, int cpu
, u64 val
)
8854 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8856 #ifndef CONFIG_64BIT
8858 * Take rq->lock to make 64-bit write safe on 32-bit platforms.
8860 raw_spin_lock_irq(&cpu_rq(cpu
)->lock
);
8862 raw_spin_unlock_irq(&cpu_rq(cpu
)->lock
);
8868 /* return total cpu usage (in nanoseconds) of a group */
8869 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8871 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8872 u64 totalcpuusage
= 0;
8875 for_each_present_cpu(i
)
8876 totalcpuusage
+= cpuacct_cpuusage_read(ca
, i
);
8878 return totalcpuusage
;
8881 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8884 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8893 for_each_present_cpu(i
)
8894 cpuacct_cpuusage_write(ca
, i
, 0);
8900 static int cpuacct_percpu_seq_read(struct cgroup
*cgroup
, struct cftype
*cft
,
8903 struct cpuacct
*ca
= cgroup_ca(cgroup
);
8907 for_each_present_cpu(i
) {
8908 percpu
= cpuacct_cpuusage_read(ca
, i
);
8909 seq_printf(m
, "%llu ", (unsigned long long) percpu
);
8911 seq_printf(m
, "\n");
8915 static const char *cpuacct_stat_desc
[] = {
8916 [CPUACCT_STAT_USER
] = "user",
8917 [CPUACCT_STAT_SYSTEM
] = "system",
8920 static int cpuacct_stats_show(struct cgroup
*cgrp
, struct cftype
*cft
,
8921 struct cgroup_map_cb
*cb
)
8923 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8926 for (i
= 0; i
< CPUACCT_STAT_NSTATS
; i
++) {
8927 s64 val
= percpu_counter_read(&ca
->cpustat
[i
]);
8928 val
= cputime64_to_clock_t(val
);
8929 cb
->fill(cb
, cpuacct_stat_desc
[i
], val
);
8934 static struct cftype files
[] = {
8937 .read_u64
= cpuusage_read
,
8938 .write_u64
= cpuusage_write
,
8941 .name
= "usage_percpu",
8942 .read_seq_string
= cpuacct_percpu_seq_read
,
8946 .read_map
= cpuacct_stats_show
,
8950 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8952 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8956 * charge this task's execution time to its accounting group.
8958 * called with rq->lock held.
8960 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8965 if (unlikely(!cpuacct_subsys
.active
))
8968 cpu
= task_cpu(tsk
);
8974 for (; ca
; ca
= ca
->parent
) {
8975 u64
*cpuusage
= per_cpu_ptr(ca
->cpuusage
, cpu
);
8976 *cpuusage
+= cputime
;
8983 * Charge the system/user time to the task's accounting group.
8985 static void cpuacct_update_stats(struct task_struct
*tsk
,
8986 enum cpuacct_stat_index idx
, cputime_t val
)
8990 if (unlikely(!cpuacct_subsys
.active
))
8997 percpu_counter_add(&ca
->cpustat
[idx
], val
);
9003 struct cgroup_subsys cpuacct_subsys
= {
9005 .create
= cpuacct_create
,
9006 .destroy
= cpuacct_destroy
,
9007 .populate
= cpuacct_populate
,
9008 .subsys_id
= cpuacct_subsys_id
,
9010 #endif /* CONFIG_CGROUP_CPUACCT */
9014 int rcu_expedited_torture_stats(char *page
)
9018 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats
);
9020 void synchronize_sched_expedited(void)
9023 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
9025 #else /* #ifndef CONFIG_SMP */
9027 static DEFINE_PER_CPU(struct migration_req
, rcu_migration_req
);
9028 static DEFINE_MUTEX(rcu_sched_expedited_mutex
);
9030 #define RCU_EXPEDITED_STATE_POST -2
9031 #define RCU_EXPEDITED_STATE_IDLE -1
9033 static int rcu_expedited_state
= RCU_EXPEDITED_STATE_IDLE
;
9035 int rcu_expedited_torture_stats(char *page
)
9040 cnt
+= sprintf(&page
[cnt
], "state: %d /", rcu_expedited_state
);
9041 for_each_online_cpu(cpu
) {
9042 cnt
+= sprintf(&page
[cnt
], " %d:%d",
9043 cpu
, per_cpu(rcu_migration_req
, cpu
).dest_cpu
);
9045 cnt
+= sprintf(&page
[cnt
], "\n");
9048 EXPORT_SYMBOL_GPL(rcu_expedited_torture_stats
);
9050 static long synchronize_sched_expedited_count
;
9053 * Wait for an rcu-sched grace period to elapse, but use "big hammer"
9054 * approach to force grace period to end quickly. This consumes
9055 * significant time on all CPUs, and is thus not recommended for
9056 * any sort of common-case code.
9058 * Note that it is illegal to call this function while holding any
9059 * lock that is acquired by a CPU-hotplug notifier. Failing to
9060 * observe this restriction will result in deadlock.
9062 void synchronize_sched_expedited(void)
9065 unsigned long flags
;
9066 bool need_full_sync
= 0;
9068 struct migration_req
*req
;
9072 smp_mb(); /* ensure prior mod happens before capturing snap. */
9073 snap
= ACCESS_ONCE(synchronize_sched_expedited_count
) + 1;
9075 while (!mutex_trylock(&rcu_sched_expedited_mutex
)) {
9077 if (trycount
++ < 10)
9078 udelay(trycount
* num_online_cpus());
9080 synchronize_sched();
9083 if (ACCESS_ONCE(synchronize_sched_expedited_count
) - snap
> 0) {
9084 smp_mb(); /* ensure test happens before caller kfree */
9089 rcu_expedited_state
= RCU_EXPEDITED_STATE_POST
;
9090 for_each_online_cpu(cpu
) {
9092 req
= &per_cpu(rcu_migration_req
, cpu
);
9093 init_completion(&req
->done
);
9095 req
->dest_cpu
= RCU_MIGRATION_NEED_QS
;
9096 raw_spin_lock_irqsave(&rq
->lock
, flags
);
9097 list_add(&req
->list
, &rq
->migration_queue
);
9098 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
9099 wake_up_process(rq
->migration_thread
);
9101 for_each_online_cpu(cpu
) {
9102 rcu_expedited_state
= cpu
;
9103 req
= &per_cpu(rcu_migration_req
, cpu
);
9105 wait_for_completion(&req
->done
);
9106 raw_spin_lock_irqsave(&rq
->lock
, flags
);
9107 if (unlikely(req
->dest_cpu
== RCU_MIGRATION_MUST_SYNC
))
9109 req
->dest_cpu
= RCU_MIGRATION_IDLE
;
9110 raw_spin_unlock_irqrestore(&rq
->lock
, flags
);
9112 rcu_expedited_state
= RCU_EXPEDITED_STATE_IDLE
;
9113 synchronize_sched_expedited_count
++;
9114 mutex_unlock(&rcu_sched_expedited_mutex
);
9117 synchronize_sched();
9119 EXPORT_SYMBOL_GPL(synchronize_sched_expedited
);
9121 #endif /* #else #ifndef CONFIG_SMP */