4 * Kernel scheduler and related syscalls
6 * Copyright (C) 1991-2002 Linus Torvalds
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
19 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
25 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
30 #include <linux/module.h>
31 #include <linux/nmi.h>
32 #include <linux/init.h>
33 #include <linux/uaccess.h>
34 #include <linux/highmem.h>
35 #include <linux/smp_lock.h>
36 #include <asm/mmu_context.h>
37 #include <linux/interrupt.h>
38 #include <linux/capability.h>
39 #include <linux/completion.h>
40 #include <linux/kernel_stat.h>
41 #include <linux/debug_locks.h>
42 #include <linux/security.h>
43 #include <linux/notifier.h>
44 #include <linux/profile.h>
45 #include <linux/freezer.h>
46 #include <linux/vmalloc.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/pid_namespace.h>
50 #include <linux/smp.h>
51 #include <linux/threads.h>
52 #include <linux/timer.h>
53 #include <linux/rcupdate.h>
54 #include <linux/cpu.h>
55 #include <linux/cpuset.h>
56 #include <linux/percpu.h>
57 #include <linux/kthread.h>
58 #include <linux/seq_file.h>
59 #include <linux/sysctl.h>
60 #include <linux/syscalls.h>
61 #include <linux/times.h>
62 #include <linux/tsacct_kern.h>
63 #include <linux/kprobes.h>
64 #include <linux/delayacct.h>
65 #include <linux/reciprocal_div.h>
66 #include <linux/unistd.h>
67 #include <linux/pagemap.h>
68 #include <linux/hrtimer.h>
69 #include <linux/tick.h>
70 #include <linux/bootmem.h>
71 #include <linux/debugfs.h>
72 #include <linux/ctype.h>
75 #include <asm/irq_regs.h>
78 * Convert user-nice values [ -20 ... 0 ... 19 ]
79 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
82 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
83 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
84 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
87 * 'User priority' is the nice value converted to something we
88 * can work with better when scaling various scheduler parameters,
89 * it's a [ 0 ... 39 ] range.
91 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
92 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
93 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
96 * Helpers for converting nanosecond timing to jiffy resolution
98 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
100 #define NICE_0_LOAD SCHED_LOAD_SCALE
101 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
104 * These are the 'tuning knobs' of the scheduler:
106 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
107 * Timeslices get refilled after they expire.
109 #define DEF_TIMESLICE (100 * HZ / 1000)
112 * single value that denotes runtime == period, ie unlimited time.
114 #define RUNTIME_INF ((u64)~0ULL)
118 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
119 * Since cpu_power is a 'constant', we can use a reciprocal divide.
121 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
123 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
127 * Each time a sched group cpu_power is changed,
128 * we must compute its reciprocal value
130 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
132 sg
->__cpu_power
+= val
;
133 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
137 static inline int rt_policy(int policy
)
139 if (unlikely(policy
== SCHED_FIFO
|| policy
== SCHED_RR
))
144 static inline int task_has_rt_policy(struct task_struct
*p
)
146 return rt_policy(p
->policy
);
150 * This is the priority-queue data structure of the RT scheduling class:
152 struct rt_prio_array
{
153 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
154 struct list_head queue
[MAX_RT_PRIO
];
157 struct rt_bandwidth
{
158 /* nests inside the rq lock: */
159 spinlock_t rt_runtime_lock
;
162 struct hrtimer rt_period_timer
;
165 static struct rt_bandwidth def_rt_bandwidth
;
167 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
169 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
171 struct rt_bandwidth
*rt_b
=
172 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
178 now
= hrtimer_cb_get_time(timer
);
179 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
184 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
187 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
191 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
193 rt_b
->rt_period
= ns_to_ktime(period
);
194 rt_b
->rt_runtime
= runtime
;
196 spin_lock_init(&rt_b
->rt_runtime_lock
);
198 hrtimer_init(&rt_b
->rt_period_timer
,
199 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
200 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
201 rt_b
->rt_period_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
204 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
208 if (rt_b
->rt_runtime
== RUNTIME_INF
)
211 if (hrtimer_active(&rt_b
->rt_period_timer
))
214 spin_lock(&rt_b
->rt_runtime_lock
);
216 if (hrtimer_active(&rt_b
->rt_period_timer
))
219 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
220 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
221 hrtimer_start(&rt_b
->rt_period_timer
,
222 rt_b
->rt_period_timer
.expires
,
225 spin_unlock(&rt_b
->rt_runtime_lock
);
228 #ifdef CONFIG_RT_GROUP_SCHED
229 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
231 hrtimer_cancel(&rt_b
->rt_period_timer
);
236 * sched_domains_mutex serializes calls to arch_init_sched_domains,
237 * detach_destroy_domains and partition_sched_domains.
239 static DEFINE_MUTEX(sched_domains_mutex
);
241 #ifdef CONFIG_GROUP_SCHED
243 #include <linux/cgroup.h>
247 static LIST_HEAD(task_groups
);
249 /* task group related information */
251 #ifdef CONFIG_CGROUP_SCHED
252 struct cgroup_subsys_state css
;
255 #ifdef CONFIG_FAIR_GROUP_SCHED
256 /* schedulable entities of this group on each cpu */
257 struct sched_entity
**se
;
258 /* runqueue "owned" by this group on each cpu */
259 struct cfs_rq
**cfs_rq
;
260 unsigned long shares
;
263 #ifdef CONFIG_RT_GROUP_SCHED
264 struct sched_rt_entity
**rt_se
;
265 struct rt_rq
**rt_rq
;
267 struct rt_bandwidth rt_bandwidth
;
271 struct list_head list
;
273 struct task_group
*parent
;
274 struct list_head siblings
;
275 struct list_head children
;
278 #ifdef CONFIG_USER_SCHED
282 * Every UID task group (including init_task_group aka UID-0) will
283 * be a child to this group.
285 struct task_group root_task_group
;
287 #ifdef CONFIG_FAIR_GROUP_SCHED
288 /* Default task group's sched entity on each cpu */
289 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
290 /* Default task group's cfs_rq on each cpu */
291 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
294 #ifdef CONFIG_RT_GROUP_SCHED
295 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
296 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
299 #define root_task_group init_task_group
302 /* task_group_lock serializes add/remove of task groups and also changes to
303 * a task group's cpu shares.
305 static DEFINE_SPINLOCK(task_group_lock
);
307 #ifdef CONFIG_FAIR_GROUP_SCHED
308 #ifdef CONFIG_USER_SCHED
309 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
311 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
315 * A weight of 0 or 1 can cause arithmetics problems.
316 * A weight of a cfs_rq is the sum of weights of which entities
317 * are queued on this cfs_rq, so a weight of a entity should not be
318 * too large, so as the shares value of a task group.
319 * (The default weight is 1024 - so there's no practical
320 * limitation from this.)
323 #define MAX_SHARES (1UL << 18)
325 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
328 /* Default task group.
329 * Every task in system belong to this group at bootup.
331 struct task_group init_task_group
;
333 /* return group to which a task belongs */
334 static inline struct task_group
*task_group(struct task_struct
*p
)
336 struct task_group
*tg
;
338 #ifdef CONFIG_USER_SCHED
340 #elif defined(CONFIG_CGROUP_SCHED)
341 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
342 struct task_group
, css
);
344 tg
= &init_task_group
;
349 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
350 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
352 #ifdef CONFIG_FAIR_GROUP_SCHED
353 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
354 p
->se
.parent
= task_group(p
)->se
[cpu
];
357 #ifdef CONFIG_RT_GROUP_SCHED
358 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
359 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
365 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
367 #endif /* CONFIG_GROUP_SCHED */
369 /* CFS-related fields in a runqueue */
371 struct load_weight load
;
372 unsigned long nr_running
;
377 struct rb_root tasks_timeline
;
378 struct rb_node
*rb_leftmost
;
380 struct list_head tasks
;
381 struct list_head
*balance_iterator
;
384 * 'curr' points to currently running entity on this cfs_rq.
385 * It is set to NULL otherwise (i.e when none are currently running).
387 struct sched_entity
*curr
, *next
;
389 unsigned long nr_spread_over
;
391 #ifdef CONFIG_FAIR_GROUP_SCHED
392 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
395 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
396 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
397 * (like users, containers etc.)
399 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
400 * list is used during load balance.
402 struct list_head leaf_cfs_rq_list
;
403 struct task_group
*tg
; /* group that "owns" this runqueue */
407 /* Real-Time classes' related field in a runqueue: */
409 struct rt_prio_array active
;
410 unsigned long rt_nr_running
;
411 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
412 int highest_prio
; /* highest queued rt task prio */
415 unsigned long rt_nr_migratory
;
421 /* Nests inside the rq lock: */
422 spinlock_t rt_runtime_lock
;
424 #ifdef CONFIG_RT_GROUP_SCHED
425 unsigned long rt_nr_boosted
;
428 struct list_head leaf_rt_rq_list
;
429 struct task_group
*tg
;
430 struct sched_rt_entity
*rt_se
;
437 * We add the notion of a root-domain which will be used to define per-domain
438 * variables. Each exclusive cpuset essentially defines an island domain by
439 * fully partitioning the member cpus from any other cpuset. Whenever a new
440 * exclusive cpuset is created, we also create and attach a new root-domain
450 * The "RT overload" flag: it gets set if a CPU has more than
451 * one runnable RT task.
458 * By default the system creates a single root-domain with all cpus as
459 * members (mimicking the global state we have today).
461 static struct root_domain def_root_domain
;
466 * This is the main, per-CPU runqueue data structure.
468 * Locking rule: those places that want to lock multiple runqueues
469 * (such as the load balancing or the thread migration code), lock
470 * acquire operations must be ordered by ascending &runqueue.
477 * nr_running and cpu_load should be in the same cacheline because
478 * remote CPUs use both these fields when doing load calculation.
480 unsigned long nr_running
;
481 #define CPU_LOAD_IDX_MAX 5
482 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
483 unsigned char idle_at_tick
;
485 unsigned long last_tick_seen
;
486 unsigned char in_nohz_recently
;
488 /* capture load from *all* tasks on this cpu: */
489 struct load_weight load
;
490 unsigned long nr_load_updates
;
496 #ifdef CONFIG_FAIR_GROUP_SCHED
497 /* list of leaf cfs_rq on this cpu: */
498 struct list_head leaf_cfs_rq_list
;
500 #ifdef CONFIG_RT_GROUP_SCHED
501 struct list_head leaf_rt_rq_list
;
505 * This is part of a global counter where only the total sum
506 * over all CPUs matters. A task can increase this counter on
507 * one CPU and if it got migrated afterwards it may decrease
508 * it on another CPU. Always updated under the runqueue lock:
510 unsigned long nr_uninterruptible
;
512 struct task_struct
*curr
, *idle
;
513 unsigned long next_balance
;
514 struct mm_struct
*prev_mm
;
521 struct root_domain
*rd
;
522 struct sched_domain
*sd
;
524 /* For active balancing */
527 /* cpu of this runqueue: */
530 struct task_struct
*migration_thread
;
531 struct list_head migration_queue
;
534 #ifdef CONFIG_SCHED_HRTICK
535 unsigned long hrtick_flags
;
536 ktime_t hrtick_expire
;
537 struct hrtimer hrtick_timer
;
540 #ifdef CONFIG_SCHEDSTATS
542 struct sched_info rq_sched_info
;
544 /* sys_sched_yield() stats */
545 unsigned int yld_exp_empty
;
546 unsigned int yld_act_empty
;
547 unsigned int yld_both_empty
;
548 unsigned int yld_count
;
550 /* schedule() stats */
551 unsigned int sched_switch
;
552 unsigned int sched_count
;
553 unsigned int sched_goidle
;
555 /* try_to_wake_up() stats */
556 unsigned int ttwu_count
;
557 unsigned int ttwu_local
;
560 unsigned int bkl_count
;
562 struct lock_class_key rq_lock_key
;
565 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
567 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
)
569 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
);
572 static inline int cpu_of(struct rq
*rq
)
582 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
583 * See detach_destroy_domains: synchronize_sched for details.
585 * The domain tree of any CPU may only be accessed from within
586 * preempt-disabled sections.
588 #define for_each_domain(cpu, __sd) \
589 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
591 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
592 #define this_rq() (&__get_cpu_var(runqueues))
593 #define task_rq(p) cpu_rq(task_cpu(p))
594 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
596 static inline void update_rq_clock(struct rq
*rq
)
598 rq
->clock
= sched_clock_cpu(cpu_of(rq
));
602 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
604 #ifdef CONFIG_SCHED_DEBUG
605 # define const_debug __read_mostly
607 # define const_debug static const
611 * Debugging: various feature bits
614 #define SCHED_FEAT(name, enabled) \
615 __SCHED_FEAT_##name ,
618 #include "sched_features.h"
623 #define SCHED_FEAT(name, enabled) \
624 (1UL << __SCHED_FEAT_##name) * enabled |
626 const_debug
unsigned int sysctl_sched_features
=
627 #include "sched_features.h"
632 #ifdef CONFIG_SCHED_DEBUG
633 #define SCHED_FEAT(name, enabled) \
636 static __read_mostly
char *sched_feat_names
[] = {
637 #include "sched_features.h"
643 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
645 filp
->private_data
= inode
->i_private
;
650 sched_feat_read(struct file
*filp
, char __user
*ubuf
,
651 size_t cnt
, loff_t
*ppos
)
658 for (i
= 0; sched_feat_names
[i
]; i
++) {
659 len
+= strlen(sched_feat_names
[i
]);
663 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
667 for (i
= 0; sched_feat_names
[i
]; i
++) {
668 if (sysctl_sched_features
& (1UL << i
))
669 r
+= sprintf(buf
+ r
, "%s ", sched_feat_names
[i
]);
671 r
+= sprintf(buf
+ r
, "NO_%s ", sched_feat_names
[i
]);
674 r
+= sprintf(buf
+ r
, "\n");
675 WARN_ON(r
>= len
+ 2);
677 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
685 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
686 size_t cnt
, loff_t
*ppos
)
696 if (copy_from_user(&buf
, ubuf
, cnt
))
701 if (strncmp(buf
, "NO_", 3) == 0) {
706 for (i
= 0; sched_feat_names
[i
]; i
++) {
707 int len
= strlen(sched_feat_names
[i
]);
709 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
711 sysctl_sched_features
&= ~(1UL << i
);
713 sysctl_sched_features
|= (1UL << i
);
718 if (!sched_feat_names
[i
])
726 static struct file_operations sched_feat_fops
= {
727 .open
= sched_feat_open
,
728 .read
= sched_feat_read
,
729 .write
= sched_feat_write
,
732 static __init
int sched_init_debug(void)
734 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
739 late_initcall(sched_init_debug
);
743 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
746 * Number of tasks to iterate in a single balance run.
747 * Limited because this is done with IRQs disabled.
749 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
752 * period over which we measure -rt task cpu usage in us.
755 unsigned int sysctl_sched_rt_period
= 1000000;
757 static __read_mostly
int scheduler_running
;
760 * part of the period that we allow rt tasks to run in us.
763 int sysctl_sched_rt_runtime
= 950000;
765 static inline u64
global_rt_period(void)
767 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
770 static inline u64
global_rt_runtime(void)
772 if (sysctl_sched_rt_period
< 0)
775 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
778 unsigned long long time_sync_thresh
= 100000;
780 static DEFINE_PER_CPU(unsigned long long, time_offset
);
781 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time
);
784 * Global lock which we take every now and then to synchronize
785 * the CPUs time. This method is not warp-safe, but it's good
786 * enough to synchronize slowly diverging time sources and thus
787 * it's good enough for tracing:
789 static DEFINE_SPINLOCK(time_sync_lock
);
790 static unsigned long long prev_global_time
;
792 static unsigned long long __sync_cpu_clock(unsigned long long time
, int cpu
)
795 * We want this inlined, to not get tracer function calls
796 * in this critical section:
798 spin_acquire(&time_sync_lock
.dep_map
, 0, 0, _THIS_IP_
);
799 __raw_spin_lock(&time_sync_lock
.raw_lock
);
801 if (time
< prev_global_time
) {
802 per_cpu(time_offset
, cpu
) += prev_global_time
- time
;
803 time
= prev_global_time
;
805 prev_global_time
= time
;
808 __raw_spin_unlock(&time_sync_lock
.raw_lock
);
809 spin_release(&time_sync_lock
.dep_map
, 1, _THIS_IP_
);
814 static unsigned long long __cpu_clock(int cpu
)
816 unsigned long long now
;
819 * Only call sched_clock() if the scheduler has already been
820 * initialized (some code might call cpu_clock() very early):
822 if (unlikely(!scheduler_running
))
825 now
= sched_clock_cpu(cpu
);
831 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
832 * clock constructed from sched_clock():
834 unsigned long long cpu_clock(int cpu
)
836 unsigned long long prev_cpu_time
, time
, delta_time
;
839 local_irq_save(flags
);
840 prev_cpu_time
= per_cpu(prev_cpu_time
, cpu
);
841 time
= __cpu_clock(cpu
) + per_cpu(time_offset
, cpu
);
842 delta_time
= time
-prev_cpu_time
;
844 if (unlikely(delta_time
> time_sync_thresh
)) {
845 time
= __sync_cpu_clock(time
, cpu
);
846 per_cpu(prev_cpu_time
, cpu
) = time
;
848 local_irq_restore(flags
);
852 EXPORT_SYMBOL_GPL(cpu_clock
);
854 #ifndef prepare_arch_switch
855 # define prepare_arch_switch(next) do { } while (0)
857 #ifndef finish_arch_switch
858 # define finish_arch_switch(prev) do { } while (0)
861 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
863 return rq
->curr
== p
;
866 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
867 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
869 return task_current(rq
, p
);
872 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
876 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
878 #ifdef CONFIG_DEBUG_SPINLOCK
879 /* this is a valid case when another task releases the spinlock */
880 rq
->lock
.owner
= current
;
883 * If we are tracking spinlock dependencies then we have to
884 * fix up the runqueue lock - which gets 'carried over' from
887 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
889 spin_unlock_irq(&rq
->lock
);
892 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
893 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
898 return task_current(rq
, p
);
902 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
906 * We can optimise this out completely for !SMP, because the
907 * SMP rebalancing from interrupt is the only thing that cares
912 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
913 spin_unlock_irq(&rq
->lock
);
915 spin_unlock(&rq
->lock
);
919 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
923 * After ->oncpu is cleared, the task can be moved to a different CPU.
924 * We must ensure this doesn't happen until the switch is completely
930 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
934 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
937 * __task_rq_lock - lock the runqueue a given task resides on.
938 * Must be called interrupts disabled.
940 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
944 struct rq
*rq
= task_rq(p
);
945 spin_lock(&rq
->lock
);
946 if (likely(rq
== task_rq(p
)))
948 spin_unlock(&rq
->lock
);
953 * task_rq_lock - lock the runqueue a given task resides on and disable
954 * interrupts. Note the ordering: we can safely lookup the task_rq without
955 * explicitly disabling preemption.
957 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
963 local_irq_save(*flags
);
965 spin_lock(&rq
->lock
);
966 if (likely(rq
== task_rq(p
)))
968 spin_unlock_irqrestore(&rq
->lock
, *flags
);
972 static void __task_rq_unlock(struct rq
*rq
)
975 spin_unlock(&rq
->lock
);
978 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
981 spin_unlock_irqrestore(&rq
->lock
, *flags
);
985 * this_rq_lock - lock this runqueue and disable interrupts.
987 static struct rq
*this_rq_lock(void)
994 spin_lock(&rq
->lock
);
999 static void __resched_task(struct task_struct
*p
, int tif_bit
);
1001 static inline void resched_task(struct task_struct
*p
)
1003 __resched_task(p
, TIF_NEED_RESCHED
);
1006 #ifdef CONFIG_SCHED_HRTICK
1008 * Use HR-timers to deliver accurate preemption points.
1010 * Its all a bit involved since we cannot program an hrt while holding the
1011 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1014 * When we get rescheduled we reprogram the hrtick_timer outside of the
1017 static inline void resched_hrt(struct task_struct
*p
)
1019 __resched_task(p
, TIF_HRTICK_RESCHED
);
1022 static inline void resched_rq(struct rq
*rq
)
1024 unsigned long flags
;
1026 spin_lock_irqsave(&rq
->lock
, flags
);
1027 resched_task(rq
->curr
);
1028 spin_unlock_irqrestore(&rq
->lock
, flags
);
1032 HRTICK_SET
, /* re-programm hrtick_timer */
1033 HRTICK_RESET
, /* not a new slice */
1034 HRTICK_BLOCK
, /* stop hrtick operations */
1039 * - enabled by features
1040 * - hrtimer is actually high res
1042 static inline int hrtick_enabled(struct rq
*rq
)
1044 if (!sched_feat(HRTICK
))
1046 if (unlikely(test_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
)))
1048 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1052 * Called to set the hrtick timer state.
1054 * called with rq->lock held and irqs disabled
1056 static void hrtick_start(struct rq
*rq
, u64 delay
, int reset
)
1058 assert_spin_locked(&rq
->lock
);
1061 * preempt at: now + delay
1064 ktime_add_ns(rq
->hrtick_timer
.base
->get_time(), delay
);
1066 * indicate we need to program the timer
1068 __set_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1070 __set_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1073 * New slices are called from the schedule path and don't need a
1074 * forced reschedule.
1077 resched_hrt(rq
->curr
);
1080 static void hrtick_clear(struct rq
*rq
)
1082 if (hrtimer_active(&rq
->hrtick_timer
))
1083 hrtimer_cancel(&rq
->hrtick_timer
);
1087 * Update the timer from the possible pending state.
1089 static void hrtick_set(struct rq
*rq
)
1093 unsigned long flags
;
1095 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1097 spin_lock_irqsave(&rq
->lock
, flags
);
1098 set
= __test_and_clear_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1099 reset
= __test_and_clear_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1100 time
= rq
->hrtick_expire
;
1101 clear_thread_flag(TIF_HRTICK_RESCHED
);
1102 spin_unlock_irqrestore(&rq
->lock
, flags
);
1105 hrtimer_start(&rq
->hrtick_timer
, time
, HRTIMER_MODE_ABS
);
1106 if (reset
&& !hrtimer_active(&rq
->hrtick_timer
))
1113 * High-resolution timer tick.
1114 * Runs from hardirq context with interrupts disabled.
1116 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1118 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1120 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1122 spin_lock(&rq
->lock
);
1123 update_rq_clock(rq
);
1124 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1125 spin_unlock(&rq
->lock
);
1127 return HRTIMER_NORESTART
;
1131 static void hotplug_hrtick_disable(int cpu
)
1133 struct rq
*rq
= cpu_rq(cpu
);
1134 unsigned long flags
;
1136 spin_lock_irqsave(&rq
->lock
, flags
);
1137 rq
->hrtick_flags
= 0;
1138 __set_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
);
1139 spin_unlock_irqrestore(&rq
->lock
, flags
);
1144 static void hotplug_hrtick_enable(int cpu
)
1146 struct rq
*rq
= cpu_rq(cpu
);
1147 unsigned long flags
;
1149 spin_lock_irqsave(&rq
->lock
, flags
);
1150 __clear_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
);
1151 spin_unlock_irqrestore(&rq
->lock
, flags
);
1155 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1157 int cpu
= (int)(long)hcpu
;
1160 case CPU_UP_CANCELED
:
1161 case CPU_UP_CANCELED_FROZEN
:
1162 case CPU_DOWN_PREPARE
:
1163 case CPU_DOWN_PREPARE_FROZEN
:
1165 case CPU_DEAD_FROZEN
:
1166 hotplug_hrtick_disable(cpu
);
1169 case CPU_UP_PREPARE
:
1170 case CPU_UP_PREPARE_FROZEN
:
1171 case CPU_DOWN_FAILED
:
1172 case CPU_DOWN_FAILED_FROZEN
:
1174 case CPU_ONLINE_FROZEN
:
1175 hotplug_hrtick_enable(cpu
);
1182 static void init_hrtick(void)
1184 hotcpu_notifier(hotplug_hrtick
, 0);
1186 #endif /* CONFIG_SMP */
1188 static void init_rq_hrtick(struct rq
*rq
)
1190 rq
->hrtick_flags
= 0;
1191 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1192 rq
->hrtick_timer
.function
= hrtick
;
1193 rq
->hrtick_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1196 void hrtick_resched(void)
1199 unsigned long flags
;
1201 if (!test_thread_flag(TIF_HRTICK_RESCHED
))
1204 local_irq_save(flags
);
1205 rq
= cpu_rq(smp_processor_id());
1207 local_irq_restore(flags
);
1210 static inline void hrtick_clear(struct rq
*rq
)
1214 static inline void hrtick_set(struct rq
*rq
)
1218 static inline void init_rq_hrtick(struct rq
*rq
)
1222 void hrtick_resched(void)
1226 static inline void init_hrtick(void)
1232 * resched_task - mark a task 'to be rescheduled now'.
1234 * On UP this means the setting of the need_resched flag, on SMP it
1235 * might also involve a cross-CPU call to trigger the scheduler on
1240 #ifndef tsk_is_polling
1241 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1244 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1248 assert_spin_locked(&task_rq(p
)->lock
);
1250 if (unlikely(test_tsk_thread_flag(p
, tif_bit
)))
1253 set_tsk_thread_flag(p
, tif_bit
);
1256 if (cpu
== smp_processor_id())
1259 /* NEED_RESCHED must be visible before we test polling */
1261 if (!tsk_is_polling(p
))
1262 smp_send_reschedule(cpu
);
1265 static void resched_cpu(int cpu
)
1267 struct rq
*rq
= cpu_rq(cpu
);
1268 unsigned long flags
;
1270 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1272 resched_task(cpu_curr(cpu
));
1273 spin_unlock_irqrestore(&rq
->lock
, flags
);
1278 * When add_timer_on() enqueues a timer into the timer wheel of an
1279 * idle CPU then this timer might expire before the next timer event
1280 * which is scheduled to wake up that CPU. In case of a completely
1281 * idle system the next event might even be infinite time into the
1282 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1283 * leaves the inner idle loop so the newly added timer is taken into
1284 * account when the CPU goes back to idle and evaluates the timer
1285 * wheel for the next timer event.
1287 void wake_up_idle_cpu(int cpu
)
1289 struct rq
*rq
= cpu_rq(cpu
);
1291 if (cpu
== smp_processor_id())
1295 * This is safe, as this function is called with the timer
1296 * wheel base lock of (cpu) held. When the CPU is on the way
1297 * to idle and has not yet set rq->curr to idle then it will
1298 * be serialized on the timer wheel base lock and take the new
1299 * timer into account automatically.
1301 if (rq
->curr
!= rq
->idle
)
1305 * We can set TIF_RESCHED on the idle task of the other CPU
1306 * lockless. The worst case is that the other CPU runs the
1307 * idle task through an additional NOOP schedule()
1309 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1311 /* NEED_RESCHED must be visible before we test polling */
1313 if (!tsk_is_polling(rq
->idle
))
1314 smp_send_reschedule(cpu
);
1319 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1321 assert_spin_locked(&task_rq(p
)->lock
);
1322 set_tsk_thread_flag(p
, tif_bit
);
1326 #if BITS_PER_LONG == 32
1327 # define WMULT_CONST (~0UL)
1329 # define WMULT_CONST (1UL << 32)
1332 #define WMULT_SHIFT 32
1335 * Shift right and round:
1337 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1339 static unsigned long
1340 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1341 struct load_weight
*lw
)
1345 if (!lw
->inv_weight
) {
1346 if (BITS_PER_LONG
> 32 && unlikely(lw
->weight
>= WMULT_CONST
))
1349 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)
1353 tmp
= (u64
)delta_exec
* weight
;
1355 * Check whether we'd overflow the 64-bit multiplication:
1357 if (unlikely(tmp
> WMULT_CONST
))
1358 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1361 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1363 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1366 static inline unsigned long
1367 calc_delta_fair(unsigned long delta_exec
, struct load_weight
*lw
)
1369 return calc_delta_mine(delta_exec
, NICE_0_LOAD
, lw
);
1372 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1378 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1385 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1386 * of tasks with abnormal "nice" values across CPUs the contribution that
1387 * each task makes to its run queue's load is weighted according to its
1388 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1389 * scaled version of the new time slice allocation that they receive on time
1393 #define WEIGHT_IDLEPRIO 2
1394 #define WMULT_IDLEPRIO (1 << 31)
1397 * Nice levels are multiplicative, with a gentle 10% change for every
1398 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1399 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1400 * that remained on nice 0.
1402 * The "10% effect" is relative and cumulative: from _any_ nice level,
1403 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1404 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1405 * If a task goes up by ~10% and another task goes down by ~10% then
1406 * the relative distance between them is ~25%.)
1408 static const int prio_to_weight
[40] = {
1409 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1410 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1411 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1412 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1413 /* 0 */ 1024, 820, 655, 526, 423,
1414 /* 5 */ 335, 272, 215, 172, 137,
1415 /* 10 */ 110, 87, 70, 56, 45,
1416 /* 15 */ 36, 29, 23, 18, 15,
1420 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1422 * In cases where the weight does not change often, we can use the
1423 * precalculated inverse to speed up arithmetics by turning divisions
1424 * into multiplications:
1426 static const u32 prio_to_wmult
[40] = {
1427 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1428 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1429 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1430 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1431 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1432 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1433 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1434 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1437 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1440 * runqueue iterator, to support SMP load-balancing between different
1441 * scheduling classes, without having to expose their internal data
1442 * structures to the load-balancing proper:
1444 struct rq_iterator
{
1446 struct task_struct
*(*start
)(void *);
1447 struct task_struct
*(*next
)(void *);
1451 static unsigned long
1452 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1453 unsigned long max_load_move
, struct sched_domain
*sd
,
1454 enum cpu_idle_type idle
, int *all_pinned
,
1455 int *this_best_prio
, struct rq_iterator
*iterator
);
1458 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1459 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1460 struct rq_iterator
*iterator
);
1463 #ifdef CONFIG_CGROUP_CPUACCT
1464 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1466 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1469 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1471 update_load_add(&rq
->load
, load
);
1474 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1476 update_load_sub(&rq
->load
, load
);
1480 static unsigned long source_load(int cpu
, int type
);
1481 static unsigned long target_load(int cpu
, int type
);
1482 static unsigned long cpu_avg_load_per_task(int cpu
);
1483 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1484 #else /* CONFIG_SMP */
1486 #ifdef CONFIG_FAIR_GROUP_SCHED
1487 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1492 #endif /* CONFIG_SMP */
1494 #include "sched_stats.h"
1495 #include "sched_idletask.c"
1496 #include "sched_fair.c"
1497 #include "sched_rt.c"
1498 #ifdef CONFIG_SCHED_DEBUG
1499 # include "sched_debug.c"
1502 #define sched_class_highest (&rt_sched_class)
1504 static inline void inc_load(struct rq
*rq
, const struct task_struct
*p
)
1506 update_load_add(&rq
->load
, p
->se
.load
.weight
);
1509 static inline void dec_load(struct rq
*rq
, const struct task_struct
*p
)
1511 update_load_sub(&rq
->load
, p
->se
.load
.weight
);
1514 static void inc_nr_running(struct task_struct
*p
, struct rq
*rq
)
1520 static void dec_nr_running(struct task_struct
*p
, struct rq
*rq
)
1526 static void set_load_weight(struct task_struct
*p
)
1528 if (task_has_rt_policy(p
)) {
1529 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1530 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1535 * SCHED_IDLE tasks get minimal weight:
1537 if (p
->policy
== SCHED_IDLE
) {
1538 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1539 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1543 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1544 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1547 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1549 sched_info_queued(p
);
1550 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
1554 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1556 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
1561 * __normal_prio - return the priority that is based on the static prio
1563 static inline int __normal_prio(struct task_struct
*p
)
1565 return p
->static_prio
;
1569 * Calculate the expected normal priority: i.e. priority
1570 * without taking RT-inheritance into account. Might be
1571 * boosted by interactivity modifiers. Changes upon fork,
1572 * setprio syscalls, and whenever the interactivity
1573 * estimator recalculates.
1575 static inline int normal_prio(struct task_struct
*p
)
1579 if (task_has_rt_policy(p
))
1580 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
1582 prio
= __normal_prio(p
);
1587 * Calculate the current priority, i.e. the priority
1588 * taken into account by the scheduler. This value might
1589 * be boosted by RT tasks, or might be boosted by
1590 * interactivity modifiers. Will be RT if the task got
1591 * RT-boosted. If not then it returns p->normal_prio.
1593 static int effective_prio(struct task_struct
*p
)
1595 p
->normal_prio
= normal_prio(p
);
1597 * If we are RT tasks or we were boosted to RT priority,
1598 * keep the priority unchanged. Otherwise, update priority
1599 * to the normal priority:
1601 if (!rt_prio(p
->prio
))
1602 return p
->normal_prio
;
1607 * activate_task - move a task to the runqueue.
1609 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1611 if (task_contributes_to_load(p
))
1612 rq
->nr_uninterruptible
--;
1614 enqueue_task(rq
, p
, wakeup
);
1615 inc_nr_running(p
, rq
);
1619 * deactivate_task - remove a task from the runqueue.
1621 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
1623 if (task_contributes_to_load(p
))
1624 rq
->nr_uninterruptible
++;
1626 dequeue_task(rq
, p
, sleep
);
1627 dec_nr_running(p
, rq
);
1631 * task_curr - is this task currently executing on a CPU?
1632 * @p: the task in question.
1634 inline int task_curr(const struct task_struct
*p
)
1636 return cpu_curr(task_cpu(p
)) == p
;
1639 /* Used instead of source_load when we know the type == 0 */
1640 unsigned long weighted_cpuload(const int cpu
)
1642 return cpu_rq(cpu
)->load
.weight
;
1645 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
1647 set_task_rq(p
, cpu
);
1650 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1651 * successfuly executed on another CPU. We must ensure that updates of
1652 * per-task data have been completed by this moment.
1655 task_thread_info(p
)->cpu
= cpu
;
1659 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
1660 const struct sched_class
*prev_class
,
1661 int oldprio
, int running
)
1663 if (prev_class
!= p
->sched_class
) {
1664 if (prev_class
->switched_from
)
1665 prev_class
->switched_from(rq
, p
, running
);
1666 p
->sched_class
->switched_to(rq
, p
, running
);
1668 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
1674 * Is this task likely cache-hot:
1677 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
1682 * Buddy candidates are cache hot:
1684 if (sched_feat(CACHE_HOT_BUDDY
) && (&p
->se
== cfs_rq_of(&p
->se
)->next
))
1687 if (p
->sched_class
!= &fair_sched_class
)
1690 if (sysctl_sched_migration_cost
== -1)
1692 if (sysctl_sched_migration_cost
== 0)
1695 delta
= now
- p
->se
.exec_start
;
1697 return delta
< (s64
)sysctl_sched_migration_cost
;
1701 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
1703 int old_cpu
= task_cpu(p
);
1704 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
1705 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
1706 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
1709 clock_offset
= old_rq
->clock
- new_rq
->clock
;
1711 #ifdef CONFIG_SCHEDSTATS
1712 if (p
->se
.wait_start
)
1713 p
->se
.wait_start
-= clock_offset
;
1714 if (p
->se
.sleep_start
)
1715 p
->se
.sleep_start
-= clock_offset
;
1716 if (p
->se
.block_start
)
1717 p
->se
.block_start
-= clock_offset
;
1718 if (old_cpu
!= new_cpu
) {
1719 schedstat_inc(p
, se
.nr_migrations
);
1720 if (task_hot(p
, old_rq
->clock
, NULL
))
1721 schedstat_inc(p
, se
.nr_forced2_migrations
);
1724 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
1725 new_cfsrq
->min_vruntime
;
1727 __set_task_cpu(p
, new_cpu
);
1730 struct migration_req
{
1731 struct list_head list
;
1733 struct task_struct
*task
;
1736 struct completion done
;
1740 * The task's runqueue lock must be held.
1741 * Returns true if you have to wait for migration thread.
1744 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
1746 struct rq
*rq
= task_rq(p
);
1749 * If the task is not on a runqueue (and not running), then
1750 * it is sufficient to simply update the task's cpu field.
1752 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
1753 set_task_cpu(p
, dest_cpu
);
1757 init_completion(&req
->done
);
1759 req
->dest_cpu
= dest_cpu
;
1760 list_add(&req
->list
, &rq
->migration_queue
);
1766 * wait_task_inactive - wait for a thread to unschedule.
1768 * The caller must ensure that the task *will* unschedule sometime soon,
1769 * else this function might spin for a *long* time. This function can't
1770 * be called with interrupts off, or it may introduce deadlock with
1771 * smp_call_function() if an IPI is sent by the same process we are
1772 * waiting to become inactive.
1774 void wait_task_inactive(struct task_struct
*p
)
1776 unsigned long flags
;
1782 * We do the initial early heuristics without holding
1783 * any task-queue locks at all. We'll only try to get
1784 * the runqueue lock when things look like they will
1790 * If the task is actively running on another CPU
1791 * still, just relax and busy-wait without holding
1794 * NOTE! Since we don't hold any locks, it's not
1795 * even sure that "rq" stays as the right runqueue!
1796 * But we don't care, since "task_running()" will
1797 * return false if the runqueue has changed and p
1798 * is actually now running somewhere else!
1800 while (task_running(rq
, p
))
1804 * Ok, time to look more closely! We need the rq
1805 * lock now, to be *sure*. If we're wrong, we'll
1806 * just go back and repeat.
1808 rq
= task_rq_lock(p
, &flags
);
1809 running
= task_running(rq
, p
);
1810 on_rq
= p
->se
.on_rq
;
1811 task_rq_unlock(rq
, &flags
);
1814 * Was it really running after all now that we
1815 * checked with the proper locks actually held?
1817 * Oops. Go back and try again..
1819 if (unlikely(running
)) {
1825 * It's not enough that it's not actively running,
1826 * it must be off the runqueue _entirely_, and not
1829 * So if it wa still runnable (but just not actively
1830 * running right now), it's preempted, and we should
1831 * yield - it could be a while.
1833 if (unlikely(on_rq
)) {
1834 schedule_timeout_uninterruptible(1);
1839 * Ahh, all good. It wasn't running, and it wasn't
1840 * runnable, which means that it will never become
1841 * running in the future either. We're all done!
1848 * kick_process - kick a running thread to enter/exit the kernel
1849 * @p: the to-be-kicked thread
1851 * Cause a process which is running on another CPU to enter
1852 * kernel-mode, without any delay. (to get signals handled.)
1854 * NOTE: this function doesnt have to take the runqueue lock,
1855 * because all it wants to ensure is that the remote task enters
1856 * the kernel. If the IPI races and the task has been migrated
1857 * to another CPU then no harm is done and the purpose has been
1860 void kick_process(struct task_struct
*p
)
1866 if ((cpu
!= smp_processor_id()) && task_curr(p
))
1867 smp_send_reschedule(cpu
);
1872 * Return a low guess at the load of a migration-source cpu weighted
1873 * according to the scheduling class and "nice" value.
1875 * We want to under-estimate the load of migration sources, to
1876 * balance conservatively.
1878 static unsigned long source_load(int cpu
, int type
)
1880 struct rq
*rq
= cpu_rq(cpu
);
1881 unsigned long total
= weighted_cpuload(cpu
);
1886 return min(rq
->cpu_load
[type
-1], total
);
1890 * Return a high guess at the load of a migration-target cpu weighted
1891 * according to the scheduling class and "nice" value.
1893 static unsigned long target_load(int cpu
, int type
)
1895 struct rq
*rq
= cpu_rq(cpu
);
1896 unsigned long total
= weighted_cpuload(cpu
);
1901 return max(rq
->cpu_load
[type
-1], total
);
1905 * Return the average load per task on the cpu's run queue
1907 static unsigned long cpu_avg_load_per_task(int cpu
)
1909 struct rq
*rq
= cpu_rq(cpu
);
1910 unsigned long total
= weighted_cpuload(cpu
);
1911 unsigned long n
= rq
->nr_running
;
1913 return n
? total
/ n
: SCHED_LOAD_SCALE
;
1917 * find_idlest_group finds and returns the least busy CPU group within the
1920 static struct sched_group
*
1921 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
1923 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
1924 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
1925 int load_idx
= sd
->forkexec_idx
;
1926 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
1929 unsigned long load
, avg_load
;
1933 /* Skip over this group if it has no CPUs allowed */
1934 if (!cpus_intersects(group
->cpumask
, p
->cpus_allowed
))
1937 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
1939 /* Tally up the load of all CPUs in the group */
1942 for_each_cpu_mask(i
, group
->cpumask
) {
1943 /* Bias balancing toward cpus of our domain */
1945 load
= source_load(i
, load_idx
);
1947 load
= target_load(i
, load_idx
);
1952 /* Adjust by relative CPU power of the group */
1953 avg_load
= sg_div_cpu_power(group
,
1954 avg_load
* SCHED_LOAD_SCALE
);
1957 this_load
= avg_load
;
1959 } else if (avg_load
< min_load
) {
1960 min_load
= avg_load
;
1963 } while (group
= group
->next
, group
!= sd
->groups
);
1965 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
1971 * find_idlest_cpu - find the idlest cpu among the cpus in group.
1974 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
,
1977 unsigned long load
, min_load
= ULONG_MAX
;
1981 /* Traverse only the allowed CPUs */
1982 cpus_and(*tmp
, group
->cpumask
, p
->cpus_allowed
);
1984 for_each_cpu_mask(i
, *tmp
) {
1985 load
= weighted_cpuload(i
);
1987 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
1997 * sched_balance_self: balance the current task (running on cpu) in domains
1998 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2001 * Balance, ie. select the least loaded group.
2003 * Returns the target CPU number, or the same CPU if no balancing is needed.
2005 * preempt must be disabled.
2007 static int sched_balance_self(int cpu
, int flag
)
2009 struct task_struct
*t
= current
;
2010 struct sched_domain
*tmp
, *sd
= NULL
;
2012 for_each_domain(cpu
, tmp
) {
2014 * If power savings logic is enabled for a domain, stop there.
2016 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2018 if (tmp
->flags
& flag
)
2023 cpumask_t span
, tmpmask
;
2024 struct sched_group
*group
;
2025 int new_cpu
, weight
;
2027 if (!(sd
->flags
& flag
)) {
2033 group
= find_idlest_group(sd
, t
, cpu
);
2039 new_cpu
= find_idlest_cpu(group
, t
, cpu
, &tmpmask
);
2040 if (new_cpu
== -1 || new_cpu
== cpu
) {
2041 /* Now try balancing at a lower domain level of cpu */
2046 /* Now try balancing at a lower domain level of new_cpu */
2049 weight
= cpus_weight(span
);
2050 for_each_domain(cpu
, tmp
) {
2051 if (weight
<= cpus_weight(tmp
->span
))
2053 if (tmp
->flags
& flag
)
2056 /* while loop will break here if sd == NULL */
2062 #endif /* CONFIG_SMP */
2065 * try_to_wake_up - wake up a thread
2066 * @p: the to-be-woken-up thread
2067 * @state: the mask of task states that can be woken
2068 * @sync: do a synchronous wakeup?
2070 * Put it on the run-queue if it's not already there. The "current"
2071 * thread is always on the run-queue (except when the actual
2072 * re-schedule is in progress), and as such you're allowed to do
2073 * the simpler "current->state = TASK_RUNNING" to mark yourself
2074 * runnable without the overhead of this.
2076 * returns failure only if the task is already active.
2078 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2080 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2081 unsigned long flags
;
2085 if (!sched_feat(SYNC_WAKEUPS
))
2089 rq
= task_rq_lock(p
, &flags
);
2090 old_state
= p
->state
;
2091 if (!(old_state
& state
))
2099 this_cpu
= smp_processor_id();
2102 if (unlikely(task_running(rq
, p
)))
2105 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2106 if (cpu
!= orig_cpu
) {
2107 set_task_cpu(p
, cpu
);
2108 task_rq_unlock(rq
, &flags
);
2109 /* might preempt at this point */
2110 rq
= task_rq_lock(p
, &flags
);
2111 old_state
= p
->state
;
2112 if (!(old_state
& state
))
2117 this_cpu
= smp_processor_id();
2121 #ifdef CONFIG_SCHEDSTATS
2122 schedstat_inc(rq
, ttwu_count
);
2123 if (cpu
== this_cpu
)
2124 schedstat_inc(rq
, ttwu_local
);
2126 struct sched_domain
*sd
;
2127 for_each_domain(this_cpu
, sd
) {
2128 if (cpu_isset(cpu
, sd
->span
)) {
2129 schedstat_inc(sd
, ttwu_wake_remote
);
2137 #endif /* CONFIG_SMP */
2138 schedstat_inc(p
, se
.nr_wakeups
);
2140 schedstat_inc(p
, se
.nr_wakeups_sync
);
2141 if (orig_cpu
!= cpu
)
2142 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2143 if (cpu
== this_cpu
)
2144 schedstat_inc(p
, se
.nr_wakeups_local
);
2146 schedstat_inc(p
, se
.nr_wakeups_remote
);
2147 update_rq_clock(rq
);
2148 activate_task(rq
, p
, 1);
2152 check_preempt_curr(rq
, p
);
2154 p
->state
= TASK_RUNNING
;
2156 if (p
->sched_class
->task_wake_up
)
2157 p
->sched_class
->task_wake_up(rq
, p
);
2160 task_rq_unlock(rq
, &flags
);
2165 int wake_up_process(struct task_struct
*p
)
2167 return try_to_wake_up(p
, TASK_ALL
, 0);
2169 EXPORT_SYMBOL(wake_up_process
);
2171 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2173 return try_to_wake_up(p
, state
, 0);
2177 * Perform scheduler related setup for a newly forked process p.
2178 * p is forked by current.
2180 * __sched_fork() is basic setup used by init_idle() too:
2182 static void __sched_fork(struct task_struct
*p
)
2184 p
->se
.exec_start
= 0;
2185 p
->se
.sum_exec_runtime
= 0;
2186 p
->se
.prev_sum_exec_runtime
= 0;
2187 p
->se
.last_wakeup
= 0;
2188 p
->se
.avg_overlap
= 0;
2190 #ifdef CONFIG_SCHEDSTATS
2191 p
->se
.wait_start
= 0;
2192 p
->se
.sum_sleep_runtime
= 0;
2193 p
->se
.sleep_start
= 0;
2194 p
->se
.block_start
= 0;
2195 p
->se
.sleep_max
= 0;
2196 p
->se
.block_max
= 0;
2198 p
->se
.slice_max
= 0;
2202 INIT_LIST_HEAD(&p
->rt
.run_list
);
2204 INIT_LIST_HEAD(&p
->se
.group_node
);
2206 #ifdef CONFIG_PREEMPT_NOTIFIERS
2207 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2211 * We mark the process as running here, but have not actually
2212 * inserted it onto the runqueue yet. This guarantees that
2213 * nobody will actually run it, and a signal or other external
2214 * event cannot wake it up and insert it on the runqueue either.
2216 p
->state
= TASK_RUNNING
;
2220 * fork()/clone()-time setup:
2222 void sched_fork(struct task_struct
*p
, int clone_flags
)
2224 int cpu
= get_cpu();
2229 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2231 set_task_cpu(p
, cpu
);
2234 * Make sure we do not leak PI boosting priority to the child:
2236 p
->prio
= current
->normal_prio
;
2237 if (!rt_prio(p
->prio
))
2238 p
->sched_class
= &fair_sched_class
;
2240 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2241 if (likely(sched_info_on()))
2242 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2244 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2247 #ifdef CONFIG_PREEMPT
2248 /* Want to start with kernel preemption disabled. */
2249 task_thread_info(p
)->preempt_count
= 1;
2255 * wake_up_new_task - wake up a newly created task for the first time.
2257 * This function will do some initial scheduler statistics housekeeping
2258 * that must be done for every newly created context, then puts the task
2259 * on the runqueue and wakes it.
2261 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2263 unsigned long flags
;
2266 rq
= task_rq_lock(p
, &flags
);
2267 BUG_ON(p
->state
!= TASK_RUNNING
);
2268 update_rq_clock(rq
);
2270 p
->prio
= effective_prio(p
);
2272 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2273 activate_task(rq
, p
, 0);
2276 * Let the scheduling class do new task startup
2277 * management (if any):
2279 p
->sched_class
->task_new(rq
, p
);
2280 inc_nr_running(p
, rq
);
2282 check_preempt_curr(rq
, p
);
2284 if (p
->sched_class
->task_wake_up
)
2285 p
->sched_class
->task_wake_up(rq
, p
);
2287 task_rq_unlock(rq
, &flags
);
2290 #ifdef CONFIG_PREEMPT_NOTIFIERS
2293 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2294 * @notifier: notifier struct to register
2296 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2298 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2300 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2303 * preempt_notifier_unregister - no longer interested in preemption notifications
2304 * @notifier: notifier struct to unregister
2306 * This is safe to call from within a preemption notifier.
2308 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2310 hlist_del(¬ifier
->link
);
2312 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2314 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2316 struct preempt_notifier
*notifier
;
2317 struct hlist_node
*node
;
2319 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2320 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2324 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2325 struct task_struct
*next
)
2327 struct preempt_notifier
*notifier
;
2328 struct hlist_node
*node
;
2330 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2331 notifier
->ops
->sched_out(notifier
, next
);
2336 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2341 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2342 struct task_struct
*next
)
2349 * prepare_task_switch - prepare to switch tasks
2350 * @rq: the runqueue preparing to switch
2351 * @prev: the current task that is being switched out
2352 * @next: the task we are going to switch to.
2354 * This is called with the rq lock held and interrupts off. It must
2355 * be paired with a subsequent finish_task_switch after the context
2358 * prepare_task_switch sets up locking and calls architecture specific
2362 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2363 struct task_struct
*next
)
2365 fire_sched_out_preempt_notifiers(prev
, next
);
2366 prepare_lock_switch(rq
, next
);
2367 prepare_arch_switch(next
);
2371 * finish_task_switch - clean up after a task-switch
2372 * @rq: runqueue associated with task-switch
2373 * @prev: the thread we just switched away from.
2375 * finish_task_switch must be called after the context switch, paired
2376 * with a prepare_task_switch call before the context switch.
2377 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2378 * and do any other architecture-specific cleanup actions.
2380 * Note that we may have delayed dropping an mm in context_switch(). If
2381 * so, we finish that here outside of the runqueue lock. (Doing it
2382 * with the lock held can cause deadlocks; see schedule() for
2385 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2386 __releases(rq
->lock
)
2388 struct mm_struct
*mm
= rq
->prev_mm
;
2394 * A task struct has one reference for the use as "current".
2395 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2396 * schedule one last time. The schedule call will never return, and
2397 * the scheduled task must drop that reference.
2398 * The test for TASK_DEAD must occur while the runqueue locks are
2399 * still held, otherwise prev could be scheduled on another cpu, die
2400 * there before we look at prev->state, and then the reference would
2402 * Manfred Spraul <manfred@colorfullife.com>
2404 prev_state
= prev
->state
;
2405 finish_arch_switch(prev
);
2406 finish_lock_switch(rq
, prev
);
2408 if (current
->sched_class
->post_schedule
)
2409 current
->sched_class
->post_schedule(rq
);
2412 fire_sched_in_preempt_notifiers(current
);
2415 if (unlikely(prev_state
== TASK_DEAD
)) {
2417 * Remove function-return probe instances associated with this
2418 * task and put them back on the free list.
2420 kprobe_flush_task(prev
);
2421 put_task_struct(prev
);
2426 * schedule_tail - first thing a freshly forked thread must call.
2427 * @prev: the thread we just switched away from.
2429 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2430 __releases(rq
->lock
)
2432 struct rq
*rq
= this_rq();
2434 finish_task_switch(rq
, prev
);
2435 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2436 /* In this case, finish_task_switch does not reenable preemption */
2439 if (current
->set_child_tid
)
2440 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2444 * context_switch - switch to the new MM and the new
2445 * thread's register state.
2448 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2449 struct task_struct
*next
)
2451 struct mm_struct
*mm
, *oldmm
;
2453 prepare_task_switch(rq
, prev
, next
);
2455 oldmm
= prev
->active_mm
;
2457 * For paravirt, this is coupled with an exit in switch_to to
2458 * combine the page table reload and the switch backend into
2461 arch_enter_lazy_cpu_mode();
2463 if (unlikely(!mm
)) {
2464 next
->active_mm
= oldmm
;
2465 atomic_inc(&oldmm
->mm_count
);
2466 enter_lazy_tlb(oldmm
, next
);
2468 switch_mm(oldmm
, mm
, next
);
2470 if (unlikely(!prev
->mm
)) {
2471 prev
->active_mm
= NULL
;
2472 rq
->prev_mm
= oldmm
;
2475 * Since the runqueue lock will be released by the next
2476 * task (which is an invalid locking op but in the case
2477 * of the scheduler it's an obvious special-case), so we
2478 * do an early lockdep release here:
2480 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2481 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2484 /* Here we just switch the register state and the stack. */
2485 switch_to(prev
, next
, prev
);
2489 * this_rq must be evaluated again because prev may have moved
2490 * CPUs since it called schedule(), thus the 'rq' on its stack
2491 * frame will be invalid.
2493 finish_task_switch(this_rq(), prev
);
2497 * nr_running, nr_uninterruptible and nr_context_switches:
2499 * externally visible scheduler statistics: current number of runnable
2500 * threads, current number of uninterruptible-sleeping threads, total
2501 * number of context switches performed since bootup.
2503 unsigned long nr_running(void)
2505 unsigned long i
, sum
= 0;
2507 for_each_online_cpu(i
)
2508 sum
+= cpu_rq(i
)->nr_running
;
2513 unsigned long nr_uninterruptible(void)
2515 unsigned long i
, sum
= 0;
2517 for_each_possible_cpu(i
)
2518 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2521 * Since we read the counters lockless, it might be slightly
2522 * inaccurate. Do not allow it to go below zero though:
2524 if (unlikely((long)sum
< 0))
2530 unsigned long long nr_context_switches(void)
2533 unsigned long long sum
= 0;
2535 for_each_possible_cpu(i
)
2536 sum
+= cpu_rq(i
)->nr_switches
;
2541 unsigned long nr_iowait(void)
2543 unsigned long i
, sum
= 0;
2545 for_each_possible_cpu(i
)
2546 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2551 unsigned long nr_active(void)
2553 unsigned long i
, running
= 0, uninterruptible
= 0;
2555 for_each_online_cpu(i
) {
2556 running
+= cpu_rq(i
)->nr_running
;
2557 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
2560 if (unlikely((long)uninterruptible
< 0))
2561 uninterruptible
= 0;
2563 return running
+ uninterruptible
;
2567 * Update rq->cpu_load[] statistics. This function is usually called every
2568 * scheduler tick (TICK_NSEC).
2570 static void update_cpu_load(struct rq
*this_rq
)
2572 unsigned long this_load
= this_rq
->load
.weight
;
2575 this_rq
->nr_load_updates
++;
2577 /* Update our load: */
2578 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
2579 unsigned long old_load
, new_load
;
2581 /* scale is effectively 1 << i now, and >> i divides by scale */
2583 old_load
= this_rq
->cpu_load
[i
];
2584 new_load
= this_load
;
2586 * Round up the averaging division if load is increasing. This
2587 * prevents us from getting stuck on 9 if the load is 10, for
2590 if (new_load
> old_load
)
2591 new_load
+= scale
-1;
2592 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
2599 * double_rq_lock - safely lock two runqueues
2601 * Note this does not disable interrupts like task_rq_lock,
2602 * you need to do so manually before calling.
2604 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
2605 __acquires(rq1
->lock
)
2606 __acquires(rq2
->lock
)
2608 BUG_ON(!irqs_disabled());
2610 spin_lock(&rq1
->lock
);
2611 __acquire(rq2
->lock
); /* Fake it out ;) */
2614 spin_lock(&rq1
->lock
);
2615 spin_lock(&rq2
->lock
);
2617 spin_lock(&rq2
->lock
);
2618 spin_lock(&rq1
->lock
);
2621 update_rq_clock(rq1
);
2622 update_rq_clock(rq2
);
2626 * double_rq_unlock - safely unlock two runqueues
2628 * Note this does not restore interrupts like task_rq_unlock,
2629 * you need to do so manually after calling.
2631 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
2632 __releases(rq1
->lock
)
2633 __releases(rq2
->lock
)
2635 spin_unlock(&rq1
->lock
);
2637 spin_unlock(&rq2
->lock
);
2639 __release(rq2
->lock
);
2643 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2645 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
2646 __releases(this_rq
->lock
)
2647 __acquires(busiest
->lock
)
2648 __acquires(this_rq
->lock
)
2652 if (unlikely(!irqs_disabled())) {
2653 /* printk() doesn't work good under rq->lock */
2654 spin_unlock(&this_rq
->lock
);
2657 if (unlikely(!spin_trylock(&busiest
->lock
))) {
2658 if (busiest
< this_rq
) {
2659 spin_unlock(&this_rq
->lock
);
2660 spin_lock(&busiest
->lock
);
2661 spin_lock(&this_rq
->lock
);
2664 spin_lock(&busiest
->lock
);
2670 * If dest_cpu is allowed for this process, migrate the task to it.
2671 * This is accomplished by forcing the cpu_allowed mask to only
2672 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2673 * the cpu_allowed mask is restored.
2675 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
2677 struct migration_req req
;
2678 unsigned long flags
;
2681 rq
= task_rq_lock(p
, &flags
);
2682 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
)
2683 || unlikely(cpu_is_offline(dest_cpu
)))
2686 /* force the process onto the specified CPU */
2687 if (migrate_task(p
, dest_cpu
, &req
)) {
2688 /* Need to wait for migration thread (might exit: take ref). */
2689 struct task_struct
*mt
= rq
->migration_thread
;
2691 get_task_struct(mt
);
2692 task_rq_unlock(rq
, &flags
);
2693 wake_up_process(mt
);
2694 put_task_struct(mt
);
2695 wait_for_completion(&req
.done
);
2700 task_rq_unlock(rq
, &flags
);
2704 * sched_exec - execve() is a valuable balancing opportunity, because at
2705 * this point the task has the smallest effective memory and cache footprint.
2707 void sched_exec(void)
2709 int new_cpu
, this_cpu
= get_cpu();
2710 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
2712 if (new_cpu
!= this_cpu
)
2713 sched_migrate_task(current
, new_cpu
);
2717 * pull_task - move a task from a remote runqueue to the local runqueue.
2718 * Both runqueues must be locked.
2720 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
2721 struct rq
*this_rq
, int this_cpu
)
2723 deactivate_task(src_rq
, p
, 0);
2724 set_task_cpu(p
, this_cpu
);
2725 activate_task(this_rq
, p
, 0);
2727 * Note that idle threads have a prio of MAX_PRIO, for this test
2728 * to be always true for them.
2730 check_preempt_curr(this_rq
, p
);
2734 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2737 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
2738 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2742 * We do not migrate tasks that are:
2743 * 1) running (obviously), or
2744 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2745 * 3) are cache-hot on their current CPU.
2747 if (!cpu_isset(this_cpu
, p
->cpus_allowed
)) {
2748 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
2753 if (task_running(rq
, p
)) {
2754 schedstat_inc(p
, se
.nr_failed_migrations_running
);
2759 * Aggressive migration if:
2760 * 1) task is cache cold, or
2761 * 2) too many balance attempts have failed.
2764 if (!task_hot(p
, rq
->clock
, sd
) ||
2765 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
2766 #ifdef CONFIG_SCHEDSTATS
2767 if (task_hot(p
, rq
->clock
, sd
)) {
2768 schedstat_inc(sd
, lb_hot_gained
[idle
]);
2769 schedstat_inc(p
, se
.nr_forced_migrations
);
2775 if (task_hot(p
, rq
->clock
, sd
)) {
2776 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
2782 static unsigned long
2783 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2784 unsigned long max_load_move
, struct sched_domain
*sd
,
2785 enum cpu_idle_type idle
, int *all_pinned
,
2786 int *this_best_prio
, struct rq_iterator
*iterator
)
2788 int loops
= 0, pulled
= 0, pinned
= 0, skip_for_load
;
2789 struct task_struct
*p
;
2790 long rem_load_move
= max_load_move
;
2792 if (max_load_move
== 0)
2798 * Start the load-balancing iterator:
2800 p
= iterator
->start(iterator
->arg
);
2802 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
2805 * To help distribute high priority tasks across CPUs we don't
2806 * skip a task if it will be the highest priority task (i.e. smallest
2807 * prio value) on its new queue regardless of its load weight
2809 skip_for_load
= (p
->se
.load
.weight
>> 1) > rem_load_move
+
2810 SCHED_LOAD_SCALE_FUZZ
;
2811 if ((skip_for_load
&& p
->prio
>= *this_best_prio
) ||
2812 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2813 p
= iterator
->next(iterator
->arg
);
2817 pull_task(busiest
, p
, this_rq
, this_cpu
);
2819 rem_load_move
-= p
->se
.load
.weight
;
2822 * We only want to steal up to the prescribed amount of weighted load.
2824 if (rem_load_move
> 0) {
2825 if (p
->prio
< *this_best_prio
)
2826 *this_best_prio
= p
->prio
;
2827 p
= iterator
->next(iterator
->arg
);
2832 * Right now, this is one of only two places pull_task() is called,
2833 * so we can safely collect pull_task() stats here rather than
2834 * inside pull_task().
2836 schedstat_add(sd
, lb_gained
[idle
], pulled
);
2839 *all_pinned
= pinned
;
2841 return max_load_move
- rem_load_move
;
2845 * move_tasks tries to move up to max_load_move weighted load from busiest to
2846 * this_rq, as part of a balancing operation within domain "sd".
2847 * Returns 1 if successful and 0 otherwise.
2849 * Called with both runqueues locked.
2851 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2852 unsigned long max_load_move
,
2853 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2856 const struct sched_class
*class = sched_class_highest
;
2857 unsigned long total_load_moved
= 0;
2858 int this_best_prio
= this_rq
->curr
->prio
;
2862 class->load_balance(this_rq
, this_cpu
, busiest
,
2863 max_load_move
- total_load_moved
,
2864 sd
, idle
, all_pinned
, &this_best_prio
);
2865 class = class->next
;
2866 } while (class && max_load_move
> total_load_moved
);
2868 return total_load_moved
> 0;
2872 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2873 struct sched_domain
*sd
, enum cpu_idle_type idle
,
2874 struct rq_iterator
*iterator
)
2876 struct task_struct
*p
= iterator
->start(iterator
->arg
);
2880 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
2881 pull_task(busiest
, p
, this_rq
, this_cpu
);
2883 * Right now, this is only the second place pull_task()
2884 * is called, so we can safely collect pull_task()
2885 * stats here rather than inside pull_task().
2887 schedstat_inc(sd
, lb_gained
[idle
]);
2891 p
= iterator
->next(iterator
->arg
);
2898 * move_one_task tries to move exactly one task from busiest to this_rq, as
2899 * part of active balancing operations within "domain".
2900 * Returns 1 if successful and 0 otherwise.
2902 * Called with both runqueues locked.
2904 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
2905 struct sched_domain
*sd
, enum cpu_idle_type idle
)
2907 const struct sched_class
*class;
2909 for (class = sched_class_highest
; class; class = class->next
)
2910 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
2917 * find_busiest_group finds and returns the busiest CPU group within the
2918 * domain. It calculates and returns the amount of weighted load which
2919 * should be moved to restore balance via the imbalance parameter.
2921 static struct sched_group
*
2922 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
2923 unsigned long *imbalance
, enum cpu_idle_type idle
,
2924 int *sd_idle
, const cpumask_t
*cpus
, int *balance
)
2926 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2927 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
2928 unsigned long max_pull
;
2929 unsigned long busiest_load_per_task
, busiest_nr_running
;
2930 unsigned long this_load_per_task
, this_nr_running
;
2931 int load_idx
, group_imb
= 0;
2932 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2933 int power_savings_balance
= 1;
2934 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
2935 unsigned long min_nr_running
= ULONG_MAX
;
2936 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
2939 max_load
= this_load
= total_load
= total_pwr
= 0;
2940 busiest_load_per_task
= busiest_nr_running
= 0;
2941 this_load_per_task
= this_nr_running
= 0;
2942 if (idle
== CPU_NOT_IDLE
)
2943 load_idx
= sd
->busy_idx
;
2944 else if (idle
== CPU_NEWLY_IDLE
)
2945 load_idx
= sd
->newidle_idx
;
2947 load_idx
= sd
->idle_idx
;
2950 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
2953 int __group_imb
= 0;
2954 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
2955 unsigned long sum_nr_running
, sum_weighted_load
;
2957 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
2960 balance_cpu
= first_cpu(group
->cpumask
);
2962 /* Tally up the load of all CPUs in the group */
2963 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
2965 min_cpu_load
= ~0UL;
2967 for_each_cpu_mask(i
, group
->cpumask
) {
2970 if (!cpu_isset(i
, *cpus
))
2975 if (*sd_idle
&& rq
->nr_running
)
2978 /* Bias balancing toward cpus of our domain */
2980 if (idle_cpu(i
) && !first_idle_cpu
) {
2985 load
= target_load(i
, load_idx
);
2987 load
= source_load(i
, load_idx
);
2988 if (load
> max_cpu_load
)
2989 max_cpu_load
= load
;
2990 if (min_cpu_load
> load
)
2991 min_cpu_load
= load
;
2995 sum_nr_running
+= rq
->nr_running
;
2996 sum_weighted_load
+= weighted_cpuload(i
);
3000 * First idle cpu or the first cpu(busiest) in this sched group
3001 * is eligible for doing load balancing at this and above
3002 * domains. In the newly idle case, we will allow all the cpu's
3003 * to do the newly idle load balance.
3005 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3006 balance_cpu
!= this_cpu
&& balance
) {
3011 total_load
+= avg_load
;
3012 total_pwr
+= group
->__cpu_power
;
3014 /* Adjust by relative CPU power of the group */
3015 avg_load
= sg_div_cpu_power(group
,
3016 avg_load
* SCHED_LOAD_SCALE
);
3018 if ((max_cpu_load
- min_cpu_load
) > SCHED_LOAD_SCALE
)
3021 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3024 this_load
= avg_load
;
3026 this_nr_running
= sum_nr_running
;
3027 this_load_per_task
= sum_weighted_load
;
3028 } else if (avg_load
> max_load
&&
3029 (sum_nr_running
> group_capacity
|| __group_imb
)) {
3030 max_load
= avg_load
;
3032 busiest_nr_running
= sum_nr_running
;
3033 busiest_load_per_task
= sum_weighted_load
;
3034 group_imb
= __group_imb
;
3037 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3039 * Busy processors will not participate in power savings
3042 if (idle
== CPU_NOT_IDLE
||
3043 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3047 * If the local group is idle or completely loaded
3048 * no need to do power savings balance at this domain
3050 if (local_group
&& (this_nr_running
>= group_capacity
||
3052 power_savings_balance
= 0;
3055 * If a group is already running at full capacity or idle,
3056 * don't include that group in power savings calculations
3058 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
3063 * Calculate the group which has the least non-idle load.
3064 * This is the group from where we need to pick up the load
3067 if ((sum_nr_running
< min_nr_running
) ||
3068 (sum_nr_running
== min_nr_running
&&
3069 first_cpu(group
->cpumask
) <
3070 first_cpu(group_min
->cpumask
))) {
3072 min_nr_running
= sum_nr_running
;
3073 min_load_per_task
= sum_weighted_load
/
3078 * Calculate the group which is almost near its
3079 * capacity but still has some space to pick up some load
3080 * from other group and save more power
3082 if (sum_nr_running
<= group_capacity
- 1) {
3083 if (sum_nr_running
> leader_nr_running
||
3084 (sum_nr_running
== leader_nr_running
&&
3085 first_cpu(group
->cpumask
) >
3086 first_cpu(group_leader
->cpumask
))) {
3087 group_leader
= group
;
3088 leader_nr_running
= sum_nr_running
;
3093 group
= group
->next
;
3094 } while (group
!= sd
->groups
);
3096 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3099 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3101 if (this_load
>= avg_load
||
3102 100*max_load
<= sd
->imbalance_pct
*this_load
)
3105 busiest_load_per_task
/= busiest_nr_running
;
3107 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3110 * We're trying to get all the cpus to the average_load, so we don't
3111 * want to push ourselves above the average load, nor do we wish to
3112 * reduce the max loaded cpu below the average load, as either of these
3113 * actions would just result in more rebalancing later, and ping-pong
3114 * tasks around. Thus we look for the minimum possible imbalance.
3115 * Negative imbalances (*we* are more loaded than anyone else) will
3116 * be counted as no imbalance for these purposes -- we can't fix that
3117 * by pulling tasks to us. Be careful of negative numbers as they'll
3118 * appear as very large values with unsigned longs.
3120 if (max_load
<= busiest_load_per_task
)
3124 * In the presence of smp nice balancing, certain scenarios can have
3125 * max load less than avg load(as we skip the groups at or below
3126 * its cpu_power, while calculating max_load..)
3128 if (max_load
< avg_load
) {
3130 goto small_imbalance
;
3133 /* Don't want to pull so many tasks that a group would go idle */
3134 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3136 /* How much load to actually move to equalise the imbalance */
3137 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3138 (avg_load
- this_load
) * this->__cpu_power
)
3142 * if *imbalance is less than the average load per runnable task
3143 * there is no gaurantee that any tasks will be moved so we'll have
3144 * a think about bumping its value to force at least one task to be
3147 if (*imbalance
< busiest_load_per_task
) {
3148 unsigned long tmp
, pwr_now
, pwr_move
;
3152 pwr_move
= pwr_now
= 0;
3154 if (this_nr_running
) {
3155 this_load_per_task
/= this_nr_running
;
3156 if (busiest_load_per_task
> this_load_per_task
)
3159 this_load_per_task
= SCHED_LOAD_SCALE
;
3161 if (max_load
- this_load
+ SCHED_LOAD_SCALE_FUZZ
>=
3162 busiest_load_per_task
* imbn
) {
3163 *imbalance
= busiest_load_per_task
;
3168 * OK, we don't have enough imbalance to justify moving tasks,
3169 * however we may be able to increase total CPU power used by
3173 pwr_now
+= busiest
->__cpu_power
*
3174 min(busiest_load_per_task
, max_load
);
3175 pwr_now
+= this->__cpu_power
*
3176 min(this_load_per_task
, this_load
);
3177 pwr_now
/= SCHED_LOAD_SCALE
;
3179 /* Amount of load we'd subtract */
3180 tmp
= sg_div_cpu_power(busiest
,
3181 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3183 pwr_move
+= busiest
->__cpu_power
*
3184 min(busiest_load_per_task
, max_load
- tmp
);
3186 /* Amount of load we'd add */
3187 if (max_load
* busiest
->__cpu_power
<
3188 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3189 tmp
= sg_div_cpu_power(this,
3190 max_load
* busiest
->__cpu_power
);
3192 tmp
= sg_div_cpu_power(this,
3193 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3194 pwr_move
+= this->__cpu_power
*
3195 min(this_load_per_task
, this_load
+ tmp
);
3196 pwr_move
/= SCHED_LOAD_SCALE
;
3198 /* Move if we gain throughput */
3199 if (pwr_move
> pwr_now
)
3200 *imbalance
= busiest_load_per_task
;
3206 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3207 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3210 if (this == group_leader
&& group_leader
!= group_min
) {
3211 *imbalance
= min_load_per_task
;
3221 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3224 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3225 unsigned long imbalance
, const cpumask_t
*cpus
)
3227 struct rq
*busiest
= NULL
, *rq
;
3228 unsigned long max_load
= 0;
3231 for_each_cpu_mask(i
, group
->cpumask
) {
3234 if (!cpu_isset(i
, *cpus
))
3238 wl
= weighted_cpuload(i
);
3240 if (rq
->nr_running
== 1 && wl
> imbalance
)
3243 if (wl
> max_load
) {
3253 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3254 * so long as it is large enough.
3256 #define MAX_PINNED_INTERVAL 512
3259 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3260 * tasks if there is an imbalance.
3262 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3263 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3264 int *balance
, cpumask_t
*cpus
)
3266 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3267 struct sched_group
*group
;
3268 unsigned long imbalance
;
3270 unsigned long flags
;
3275 * When power savings policy is enabled for the parent domain, idle
3276 * sibling can pick up load irrespective of busy siblings. In this case,
3277 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3278 * portraying it as CPU_NOT_IDLE.
3280 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3281 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3284 schedstat_inc(sd
, lb_count
[idle
]);
3287 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3294 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3298 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3300 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3304 BUG_ON(busiest
== this_rq
);
3306 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3309 if (busiest
->nr_running
> 1) {
3311 * Attempt to move tasks. If find_busiest_group has found
3312 * an imbalance but busiest->nr_running <= 1, the group is
3313 * still unbalanced. ld_moved simply stays zero, so it is
3314 * correctly treated as an imbalance.
3316 local_irq_save(flags
);
3317 double_rq_lock(this_rq
, busiest
);
3318 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3319 imbalance
, sd
, idle
, &all_pinned
);
3320 double_rq_unlock(this_rq
, busiest
);
3321 local_irq_restore(flags
);
3324 * some other cpu did the load balance for us.
3326 if (ld_moved
&& this_cpu
!= smp_processor_id())
3327 resched_cpu(this_cpu
);
3329 /* All tasks on this runqueue were pinned by CPU affinity */
3330 if (unlikely(all_pinned
)) {
3331 cpu_clear(cpu_of(busiest
), *cpus
);
3332 if (!cpus_empty(*cpus
))
3339 schedstat_inc(sd
, lb_failed
[idle
]);
3340 sd
->nr_balance_failed
++;
3342 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3344 spin_lock_irqsave(&busiest
->lock
, flags
);
3346 /* don't kick the migration_thread, if the curr
3347 * task on busiest cpu can't be moved to this_cpu
3349 if (!cpu_isset(this_cpu
, busiest
->curr
->cpus_allowed
)) {
3350 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3352 goto out_one_pinned
;
3355 if (!busiest
->active_balance
) {
3356 busiest
->active_balance
= 1;
3357 busiest
->push_cpu
= this_cpu
;
3360 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3362 wake_up_process(busiest
->migration_thread
);
3365 * We've kicked active balancing, reset the failure
3368 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3371 sd
->nr_balance_failed
= 0;
3373 if (likely(!active_balance
)) {
3374 /* We were unbalanced, so reset the balancing interval */
3375 sd
->balance_interval
= sd
->min_interval
;
3378 * If we've begun active balancing, start to back off. This
3379 * case may not be covered by the all_pinned logic if there
3380 * is only 1 task on the busy runqueue (because we don't call
3383 if (sd
->balance_interval
< sd
->max_interval
)
3384 sd
->balance_interval
*= 2;
3387 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3388 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3393 schedstat_inc(sd
, lb_balanced
[idle
]);
3395 sd
->nr_balance_failed
= 0;
3398 /* tune up the balancing interval */
3399 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3400 (sd
->balance_interval
< sd
->max_interval
))
3401 sd
->balance_interval
*= 2;
3403 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3404 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3410 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3411 * tasks if there is an imbalance.
3413 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3414 * this_rq is locked.
3417 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3420 struct sched_group
*group
;
3421 struct rq
*busiest
= NULL
;
3422 unsigned long imbalance
;
3430 * When power savings policy is enabled for the parent domain, idle
3431 * sibling can pick up load irrespective of busy siblings. In this case,
3432 * let the state of idle sibling percolate up as IDLE, instead of
3433 * portraying it as CPU_NOT_IDLE.
3435 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3436 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3439 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3441 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3442 &sd_idle
, cpus
, NULL
);
3444 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3448 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3450 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3454 BUG_ON(busiest
== this_rq
);
3456 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3459 if (busiest
->nr_running
> 1) {
3460 /* Attempt to move tasks */
3461 double_lock_balance(this_rq
, busiest
);
3462 /* this_rq->clock is already updated */
3463 update_rq_clock(busiest
);
3464 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3465 imbalance
, sd
, CPU_NEWLY_IDLE
,
3467 spin_unlock(&busiest
->lock
);
3469 if (unlikely(all_pinned
)) {
3470 cpu_clear(cpu_of(busiest
), *cpus
);
3471 if (!cpus_empty(*cpus
))
3477 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3478 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3479 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3482 sd
->nr_balance_failed
= 0;
3487 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3488 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3489 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3491 sd
->nr_balance_failed
= 0;
3497 * idle_balance is called by schedule() if this_cpu is about to become
3498 * idle. Attempts to pull tasks from other CPUs.
3500 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3502 struct sched_domain
*sd
;
3503 int pulled_task
= -1;
3504 unsigned long next_balance
= jiffies
+ HZ
;
3507 for_each_domain(this_cpu
, sd
) {
3508 unsigned long interval
;
3510 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3513 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3514 /* If we've pulled tasks over stop searching: */
3515 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3518 interval
= msecs_to_jiffies(sd
->balance_interval
);
3519 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3520 next_balance
= sd
->last_balance
+ interval
;
3524 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3526 * We are going idle. next_balance may be set based on
3527 * a busy processor. So reset next_balance.
3529 this_rq
->next_balance
= next_balance
;
3534 * active_load_balance is run by migration threads. It pushes running tasks
3535 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3536 * running on each physical CPU where possible, and avoids physical /
3537 * logical imbalances.
3539 * Called with busiest_rq locked.
3541 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3543 int target_cpu
= busiest_rq
->push_cpu
;
3544 struct sched_domain
*sd
;
3545 struct rq
*target_rq
;
3547 /* Is there any task to move? */
3548 if (busiest_rq
->nr_running
<= 1)
3551 target_rq
= cpu_rq(target_cpu
);
3554 * This condition is "impossible", if it occurs
3555 * we need to fix it. Originally reported by
3556 * Bjorn Helgaas on a 128-cpu setup.
3558 BUG_ON(busiest_rq
== target_rq
);
3560 /* move a task from busiest_rq to target_rq */
3561 double_lock_balance(busiest_rq
, target_rq
);
3562 update_rq_clock(busiest_rq
);
3563 update_rq_clock(target_rq
);
3565 /* Search for an sd spanning us and the target CPU. */
3566 for_each_domain(target_cpu
, sd
) {
3567 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
3568 cpu_isset(busiest_cpu
, sd
->span
))
3573 schedstat_inc(sd
, alb_count
);
3575 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
3577 schedstat_inc(sd
, alb_pushed
);
3579 schedstat_inc(sd
, alb_failed
);
3581 spin_unlock(&target_rq
->lock
);
3586 atomic_t load_balancer
;
3588 } nohz ____cacheline_aligned
= {
3589 .load_balancer
= ATOMIC_INIT(-1),
3590 .cpu_mask
= CPU_MASK_NONE
,
3594 * This routine will try to nominate the ilb (idle load balancing)
3595 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3596 * load balancing on behalf of all those cpus. If all the cpus in the system
3597 * go into this tickless mode, then there will be no ilb owner (as there is
3598 * no need for one) and all the cpus will sleep till the next wakeup event
3601 * For the ilb owner, tick is not stopped. And this tick will be used
3602 * for idle load balancing. ilb owner will still be part of
3605 * While stopping the tick, this cpu will become the ilb owner if there
3606 * is no other owner. And will be the owner till that cpu becomes busy
3607 * or if all cpus in the system stop their ticks at which point
3608 * there is no need for ilb owner.
3610 * When the ilb owner becomes busy, it nominates another owner, during the
3611 * next busy scheduler_tick()
3613 int select_nohz_load_balancer(int stop_tick
)
3615 int cpu
= smp_processor_id();
3618 cpu_set(cpu
, nohz
.cpu_mask
);
3619 cpu_rq(cpu
)->in_nohz_recently
= 1;
3622 * If we are going offline and still the leader, give up!
3624 if (cpu_is_offline(cpu
) &&
3625 atomic_read(&nohz
.load_balancer
) == cpu
) {
3626 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3631 /* time for ilb owner also to sleep */
3632 if (cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3633 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3634 atomic_set(&nohz
.load_balancer
, -1);
3638 if (atomic_read(&nohz
.load_balancer
) == -1) {
3639 /* make me the ilb owner */
3640 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
3642 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
3645 if (!cpu_isset(cpu
, nohz
.cpu_mask
))
3648 cpu_clear(cpu
, nohz
.cpu_mask
);
3650 if (atomic_read(&nohz
.load_balancer
) == cpu
)
3651 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
3658 static DEFINE_SPINLOCK(balancing
);
3661 * It checks each scheduling domain to see if it is due to be balanced,
3662 * and initiates a balancing operation if so.
3664 * Balancing parameters are set up in arch_init_sched_domains.
3666 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
3669 struct rq
*rq
= cpu_rq(cpu
);
3670 unsigned long interval
;
3671 struct sched_domain
*sd
;
3672 /* Earliest time when we have to do rebalance again */
3673 unsigned long next_balance
= jiffies
+ 60*HZ
;
3674 int update_next_balance
= 0;
3677 for_each_domain(cpu
, sd
) {
3678 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3681 interval
= sd
->balance_interval
;
3682 if (idle
!= CPU_IDLE
)
3683 interval
*= sd
->busy_factor
;
3685 /* scale ms to jiffies */
3686 interval
= msecs_to_jiffies(interval
);
3687 if (unlikely(!interval
))
3689 if (interval
> HZ
*NR_CPUS
/10)
3690 interval
= HZ
*NR_CPUS
/10;
3693 if (sd
->flags
& SD_SERIALIZE
) {
3694 if (!spin_trylock(&balancing
))
3698 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
3699 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, &tmp
)) {
3701 * We've pulled tasks over so either we're no
3702 * longer idle, or one of our SMT siblings is
3705 idle
= CPU_NOT_IDLE
;
3707 sd
->last_balance
= jiffies
;
3709 if (sd
->flags
& SD_SERIALIZE
)
3710 spin_unlock(&balancing
);
3712 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
3713 next_balance
= sd
->last_balance
+ interval
;
3714 update_next_balance
= 1;
3718 * Stop the load balance at this level. There is another
3719 * CPU in our sched group which is doing load balancing more
3727 * next_balance will be updated only when there is a need.
3728 * When the cpu is attached to null domain for ex, it will not be
3731 if (likely(update_next_balance
))
3732 rq
->next_balance
= next_balance
;
3736 * run_rebalance_domains is triggered when needed from the scheduler tick.
3737 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3738 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3740 static void run_rebalance_domains(struct softirq_action
*h
)
3742 int this_cpu
= smp_processor_id();
3743 struct rq
*this_rq
= cpu_rq(this_cpu
);
3744 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
3745 CPU_IDLE
: CPU_NOT_IDLE
;
3747 rebalance_domains(this_cpu
, idle
);
3751 * If this cpu is the owner for idle load balancing, then do the
3752 * balancing on behalf of the other idle cpus whose ticks are
3755 if (this_rq
->idle_at_tick
&&
3756 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
3757 cpumask_t cpus
= nohz
.cpu_mask
;
3761 cpu_clear(this_cpu
, cpus
);
3762 for_each_cpu_mask(balance_cpu
, cpus
) {
3764 * If this cpu gets work to do, stop the load balancing
3765 * work being done for other cpus. Next load
3766 * balancing owner will pick it up.
3771 rebalance_domains(balance_cpu
, CPU_IDLE
);
3773 rq
= cpu_rq(balance_cpu
);
3774 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
3775 this_rq
->next_balance
= rq
->next_balance
;
3782 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3784 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3785 * idle load balancing owner or decide to stop the periodic load balancing,
3786 * if the whole system is idle.
3788 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
3792 * If we were in the nohz mode recently and busy at the current
3793 * scheduler tick, then check if we need to nominate new idle
3796 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
3797 rq
->in_nohz_recently
= 0;
3799 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
3800 cpu_clear(cpu
, nohz
.cpu_mask
);
3801 atomic_set(&nohz
.load_balancer
, -1);
3804 if (atomic_read(&nohz
.load_balancer
) == -1) {
3806 * simple selection for now: Nominate the
3807 * first cpu in the nohz list to be the next
3810 * TBD: Traverse the sched domains and nominate
3811 * the nearest cpu in the nohz.cpu_mask.
3813 int ilb
= first_cpu(nohz
.cpu_mask
);
3815 if (ilb
< nr_cpu_ids
)
3821 * If this cpu is idle and doing idle load balancing for all the
3822 * cpus with ticks stopped, is it time for that to stop?
3824 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
3825 cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
3831 * If this cpu is idle and the idle load balancing is done by
3832 * someone else, then no need raise the SCHED_SOFTIRQ
3834 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
3835 cpu_isset(cpu
, nohz
.cpu_mask
))
3838 if (time_after_eq(jiffies
, rq
->next_balance
))
3839 raise_softirq(SCHED_SOFTIRQ
);
3842 #else /* CONFIG_SMP */
3845 * on UP we do not need to balance between CPUs:
3847 static inline void idle_balance(int cpu
, struct rq
*rq
)
3853 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
3855 EXPORT_PER_CPU_SYMBOL(kstat
);
3858 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3859 * that have not yet been banked in case the task is currently running.
3861 unsigned long long task_sched_runtime(struct task_struct
*p
)
3863 unsigned long flags
;
3867 rq
= task_rq_lock(p
, &flags
);
3868 ns
= p
->se
.sum_exec_runtime
;
3869 if (task_current(rq
, p
)) {
3870 update_rq_clock(rq
);
3871 delta_exec
= rq
->clock
- p
->se
.exec_start
;
3872 if ((s64
)delta_exec
> 0)
3875 task_rq_unlock(rq
, &flags
);
3881 * Account user cpu time to a process.
3882 * @p: the process that the cpu time gets accounted to
3883 * @cputime: the cpu time spent in user space since the last update
3885 void account_user_time(struct task_struct
*p
, cputime_t cputime
)
3887 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3890 p
->utime
= cputime_add(p
->utime
, cputime
);
3892 /* Add user time to cpustat. */
3893 tmp
= cputime_to_cputime64(cputime
);
3894 if (TASK_NICE(p
) > 0)
3895 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
3897 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3901 * Account guest cpu time to a process.
3902 * @p: the process that the cpu time gets accounted to
3903 * @cputime: the cpu time spent in virtual machine since the last update
3905 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
)
3908 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3910 tmp
= cputime_to_cputime64(cputime
);
3912 p
->utime
= cputime_add(p
->utime
, cputime
);
3913 p
->gtime
= cputime_add(p
->gtime
, cputime
);
3915 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
3916 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
3920 * Account scaled user cpu time to a process.
3921 * @p: the process that the cpu time gets accounted to
3922 * @cputime: the cpu time spent in user space since the last update
3924 void account_user_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3926 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime
);
3930 * Account system cpu time to a process.
3931 * @p: the process that the cpu time gets accounted to
3932 * @hardirq_offset: the offset to subtract from hardirq_count()
3933 * @cputime: the cpu time spent in kernel space since the last update
3935 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
3938 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3939 struct rq
*rq
= this_rq();
3942 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
3943 account_guest_time(p
, cputime
);
3947 p
->stime
= cputime_add(p
->stime
, cputime
);
3949 /* Add system time to cpustat. */
3950 tmp
= cputime_to_cputime64(cputime
);
3951 if (hardirq_count() - hardirq_offset
)
3952 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
3953 else if (softirq_count())
3954 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
3955 else if (p
!= rq
->idle
)
3956 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
3957 else if (atomic_read(&rq
->nr_iowait
) > 0)
3958 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3960 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3961 /* Account for system time used */
3962 acct_update_integrals(p
);
3966 * Account scaled system cpu time to a process.
3967 * @p: the process that the cpu time gets accounted to
3968 * @hardirq_offset: the offset to subtract from hardirq_count()
3969 * @cputime: the cpu time spent in kernel space since the last update
3971 void account_system_time_scaled(struct task_struct
*p
, cputime_t cputime
)
3973 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime
);
3977 * Account for involuntary wait time.
3978 * @p: the process from which the cpu time has been stolen
3979 * @steal: the cpu time spent in involuntary wait
3981 void account_steal_time(struct task_struct
*p
, cputime_t steal
)
3983 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
3984 cputime64_t tmp
= cputime_to_cputime64(steal
);
3985 struct rq
*rq
= this_rq();
3987 if (p
== rq
->idle
) {
3988 p
->stime
= cputime_add(p
->stime
, steal
);
3989 if (atomic_read(&rq
->nr_iowait
) > 0)
3990 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
3992 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
3994 cpustat
->steal
= cputime64_add(cpustat
->steal
, tmp
);
3998 * This function gets called by the timer code, with HZ frequency.
3999 * We call it with interrupts disabled.
4001 * It also gets called by the fork code, when changing the parent's
4004 void scheduler_tick(void)
4006 int cpu
= smp_processor_id();
4007 struct rq
*rq
= cpu_rq(cpu
);
4008 struct task_struct
*curr
= rq
->curr
;
4012 spin_lock(&rq
->lock
);
4013 update_rq_clock(rq
);
4014 update_cpu_load(rq
);
4015 curr
->sched_class
->task_tick(rq
, curr
, 0);
4016 spin_unlock(&rq
->lock
);
4019 rq
->idle_at_tick
= idle_cpu(cpu
);
4020 trigger_load_balance(rq
, cpu
);
4024 #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
4026 void __kprobes
add_preempt_count(int val
)
4031 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4033 preempt_count() += val
;
4035 * Spinlock count overflowing soon?
4037 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4040 EXPORT_SYMBOL(add_preempt_count
);
4042 void __kprobes
sub_preempt_count(int val
)
4047 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
4050 * Is the spinlock portion underflowing?
4052 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4053 !(preempt_count() & PREEMPT_MASK
)))
4056 preempt_count() -= val
;
4058 EXPORT_SYMBOL(sub_preempt_count
);
4063 * Print scheduling while atomic bug:
4065 static noinline
void __schedule_bug(struct task_struct
*prev
)
4067 struct pt_regs
*regs
= get_irq_regs();
4069 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4070 prev
->comm
, prev
->pid
, preempt_count());
4072 debug_show_held_locks(prev
);
4073 if (irqs_disabled())
4074 print_irqtrace_events(prev
);
4083 * Various schedule()-time debugging checks and statistics:
4085 static inline void schedule_debug(struct task_struct
*prev
)
4088 * Test if we are atomic. Since do_exit() needs to call into
4089 * schedule() atomically, we ignore that path for now.
4090 * Otherwise, whine if we are scheduling when we should not be.
4092 if (unlikely(in_atomic_preempt_off() && !prev
->exit_state
))
4093 __schedule_bug(prev
);
4095 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4097 schedstat_inc(this_rq(), sched_count
);
4098 #ifdef CONFIG_SCHEDSTATS
4099 if (unlikely(prev
->lock_depth
>= 0)) {
4100 schedstat_inc(this_rq(), bkl_count
);
4101 schedstat_inc(prev
, sched_info
.bkl_count
);
4107 * Pick up the highest-prio task:
4109 static inline struct task_struct
*
4110 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4112 const struct sched_class
*class;
4113 struct task_struct
*p
;
4116 * Optimization: we know that if all tasks are in
4117 * the fair class we can call that function directly:
4119 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4120 p
= fair_sched_class
.pick_next_task(rq
);
4125 class = sched_class_highest
;
4127 p
= class->pick_next_task(rq
);
4131 * Will never be NULL as the idle class always
4132 * returns a non-NULL p:
4134 class = class->next
;
4139 * schedule() is the main scheduler function.
4141 asmlinkage
void __sched
schedule(void)
4143 struct task_struct
*prev
, *next
;
4144 unsigned long *switch_count
;
4150 cpu
= smp_processor_id();
4154 switch_count
= &prev
->nivcsw
;
4156 release_kernel_lock(prev
);
4157 need_resched_nonpreemptible
:
4159 schedule_debug(prev
);
4164 * Do the rq-clock update outside the rq lock:
4166 local_irq_disable();
4167 update_rq_clock(rq
);
4168 spin_lock(&rq
->lock
);
4169 clear_tsk_need_resched(prev
);
4171 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4172 if (unlikely(signal_pending_state(prev
->state
, prev
)))
4173 prev
->state
= TASK_RUNNING
;
4175 deactivate_task(rq
, prev
, 1);
4176 switch_count
= &prev
->nvcsw
;
4180 if (prev
->sched_class
->pre_schedule
)
4181 prev
->sched_class
->pre_schedule(rq
, prev
);
4184 if (unlikely(!rq
->nr_running
))
4185 idle_balance(cpu
, rq
);
4187 prev
->sched_class
->put_prev_task(rq
, prev
);
4188 next
= pick_next_task(rq
, prev
);
4190 if (likely(prev
!= next
)) {
4191 sched_info_switch(prev
, next
);
4197 context_switch(rq
, prev
, next
); /* unlocks the rq */
4199 * the context switch might have flipped the stack from under
4200 * us, hence refresh the local variables.
4202 cpu
= smp_processor_id();
4205 spin_unlock_irq(&rq
->lock
);
4209 if (unlikely(reacquire_kernel_lock(current
) < 0))
4210 goto need_resched_nonpreemptible
;
4212 preempt_enable_no_resched();
4213 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4216 EXPORT_SYMBOL(schedule
);
4218 #ifdef CONFIG_PREEMPT
4220 * this is the entry point to schedule() from in-kernel preemption
4221 * off of preempt_enable. Kernel preemptions off return from interrupt
4222 * occur there and call schedule directly.
4224 asmlinkage
void __sched
preempt_schedule(void)
4226 struct thread_info
*ti
= current_thread_info();
4229 * If there is a non-zero preempt_count or interrupts are disabled,
4230 * we do not want to preempt the current task. Just return..
4232 if (likely(ti
->preempt_count
|| irqs_disabled()))
4236 add_preempt_count(PREEMPT_ACTIVE
);
4238 sub_preempt_count(PREEMPT_ACTIVE
);
4241 * Check again in case we missed a preemption opportunity
4242 * between schedule and now.
4245 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4247 EXPORT_SYMBOL(preempt_schedule
);
4250 * this is the entry point to schedule() from kernel preemption
4251 * off of irq context.
4252 * Note, that this is called and return with irqs disabled. This will
4253 * protect us against recursive calling from irq.
4255 asmlinkage
void __sched
preempt_schedule_irq(void)
4257 struct thread_info
*ti
= current_thread_info();
4259 /* Catch callers which need to be fixed */
4260 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4263 add_preempt_count(PREEMPT_ACTIVE
);
4266 local_irq_disable();
4267 sub_preempt_count(PREEMPT_ACTIVE
);
4270 * Check again in case we missed a preemption opportunity
4271 * between schedule and now.
4274 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4277 #endif /* CONFIG_PREEMPT */
4279 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4282 return try_to_wake_up(curr
->private, mode
, sync
);
4284 EXPORT_SYMBOL(default_wake_function
);
4287 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4288 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4289 * number) then we wake all the non-exclusive tasks and one exclusive task.
4291 * There are circumstances in which we can try to wake a task which has already
4292 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4293 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4295 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4296 int nr_exclusive
, int sync
, void *key
)
4298 wait_queue_t
*curr
, *next
;
4300 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4301 unsigned flags
= curr
->flags
;
4303 if (curr
->func(curr
, mode
, sync
, key
) &&
4304 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4310 * __wake_up - wake up threads blocked on a waitqueue.
4312 * @mode: which threads
4313 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4314 * @key: is directly passed to the wakeup function
4316 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4317 int nr_exclusive
, void *key
)
4319 unsigned long flags
;
4321 spin_lock_irqsave(&q
->lock
, flags
);
4322 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4323 spin_unlock_irqrestore(&q
->lock
, flags
);
4325 EXPORT_SYMBOL(__wake_up
);
4328 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4330 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4332 __wake_up_common(q
, mode
, 1, 0, NULL
);
4336 * __wake_up_sync - wake up threads blocked on a waitqueue.
4338 * @mode: which threads
4339 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4341 * The sync wakeup differs that the waker knows that it will schedule
4342 * away soon, so while the target thread will be woken up, it will not
4343 * be migrated to another CPU - ie. the two threads are 'synchronized'
4344 * with each other. This can prevent needless bouncing between CPUs.
4346 * On UP it can prevent extra preemption.
4349 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4351 unsigned long flags
;
4357 if (unlikely(!nr_exclusive
))
4360 spin_lock_irqsave(&q
->lock
, flags
);
4361 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4362 spin_unlock_irqrestore(&q
->lock
, flags
);
4364 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4366 void complete(struct completion
*x
)
4368 unsigned long flags
;
4370 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4372 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4373 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4375 EXPORT_SYMBOL(complete
);
4377 void complete_all(struct completion
*x
)
4379 unsigned long flags
;
4381 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4382 x
->done
+= UINT_MAX
/2;
4383 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4384 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4386 EXPORT_SYMBOL(complete_all
);
4388 static inline long __sched
4389 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4392 DECLARE_WAITQUEUE(wait
, current
);
4394 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4395 __add_wait_queue_tail(&x
->wait
, &wait
);
4397 if ((state
== TASK_INTERRUPTIBLE
&&
4398 signal_pending(current
)) ||
4399 (state
== TASK_KILLABLE
&&
4400 fatal_signal_pending(current
))) {
4401 timeout
= -ERESTARTSYS
;
4404 __set_current_state(state
);
4405 spin_unlock_irq(&x
->wait
.lock
);
4406 timeout
= schedule_timeout(timeout
);
4407 spin_lock_irq(&x
->wait
.lock
);
4408 } while (!x
->done
&& timeout
);
4409 __remove_wait_queue(&x
->wait
, &wait
);
4414 return timeout
?: 1;
4418 wait_for_common(struct completion
*x
, long timeout
, int state
)
4422 spin_lock_irq(&x
->wait
.lock
);
4423 timeout
= do_wait_for_common(x
, timeout
, state
);
4424 spin_unlock_irq(&x
->wait
.lock
);
4428 void __sched
wait_for_completion(struct completion
*x
)
4430 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4432 EXPORT_SYMBOL(wait_for_completion
);
4434 unsigned long __sched
4435 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4437 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4439 EXPORT_SYMBOL(wait_for_completion_timeout
);
4441 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4443 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4444 if (t
== -ERESTARTSYS
)
4448 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4450 unsigned long __sched
4451 wait_for_completion_interruptible_timeout(struct completion
*x
,
4452 unsigned long timeout
)
4454 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4456 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4458 int __sched
wait_for_completion_killable(struct completion
*x
)
4460 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4461 if (t
== -ERESTARTSYS
)
4465 EXPORT_SYMBOL(wait_for_completion_killable
);
4468 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4470 unsigned long flags
;
4473 init_waitqueue_entry(&wait
, current
);
4475 __set_current_state(state
);
4477 spin_lock_irqsave(&q
->lock
, flags
);
4478 __add_wait_queue(q
, &wait
);
4479 spin_unlock(&q
->lock
);
4480 timeout
= schedule_timeout(timeout
);
4481 spin_lock_irq(&q
->lock
);
4482 __remove_wait_queue(q
, &wait
);
4483 spin_unlock_irqrestore(&q
->lock
, flags
);
4488 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4490 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4492 EXPORT_SYMBOL(interruptible_sleep_on
);
4495 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4497 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4499 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4501 void __sched
sleep_on(wait_queue_head_t
*q
)
4503 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4505 EXPORT_SYMBOL(sleep_on
);
4507 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4509 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
4511 EXPORT_SYMBOL(sleep_on_timeout
);
4513 #ifdef CONFIG_RT_MUTEXES
4516 * rt_mutex_setprio - set the current priority of a task
4518 * @prio: prio value (kernel-internal form)
4520 * This function changes the 'effective' priority of a task. It does
4521 * not touch ->normal_prio like __setscheduler().
4523 * Used by the rt_mutex code to implement priority inheritance logic.
4525 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
4527 unsigned long flags
;
4528 int oldprio
, on_rq
, running
;
4530 const struct sched_class
*prev_class
= p
->sched_class
;
4532 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
4534 rq
= task_rq_lock(p
, &flags
);
4535 update_rq_clock(rq
);
4538 on_rq
= p
->se
.on_rq
;
4539 running
= task_current(rq
, p
);
4541 dequeue_task(rq
, p
, 0);
4543 p
->sched_class
->put_prev_task(rq
, p
);
4546 p
->sched_class
= &rt_sched_class
;
4548 p
->sched_class
= &fair_sched_class
;
4553 p
->sched_class
->set_curr_task(rq
);
4555 enqueue_task(rq
, p
, 0);
4557 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4559 task_rq_unlock(rq
, &flags
);
4564 void set_user_nice(struct task_struct
*p
, long nice
)
4566 int old_prio
, delta
, on_rq
;
4567 unsigned long flags
;
4570 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
4573 * We have to be careful, if called from sys_setpriority(),
4574 * the task might be in the middle of scheduling on another CPU.
4576 rq
= task_rq_lock(p
, &flags
);
4577 update_rq_clock(rq
);
4579 * The RT priorities are set via sched_setscheduler(), but we still
4580 * allow the 'normal' nice value to be set - but as expected
4581 * it wont have any effect on scheduling until the task is
4582 * SCHED_FIFO/SCHED_RR:
4584 if (task_has_rt_policy(p
)) {
4585 p
->static_prio
= NICE_TO_PRIO(nice
);
4588 on_rq
= p
->se
.on_rq
;
4590 dequeue_task(rq
, p
, 0);
4594 p
->static_prio
= NICE_TO_PRIO(nice
);
4597 p
->prio
= effective_prio(p
);
4598 delta
= p
->prio
- old_prio
;
4601 enqueue_task(rq
, p
, 0);
4604 * If the task increased its priority or is running and
4605 * lowered its priority, then reschedule its CPU:
4607 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
4608 resched_task(rq
->curr
);
4611 task_rq_unlock(rq
, &flags
);
4613 EXPORT_SYMBOL(set_user_nice
);
4616 * can_nice - check if a task can reduce its nice value
4620 int can_nice(const struct task_struct
*p
, const int nice
)
4622 /* convert nice value [19,-20] to rlimit style value [1,40] */
4623 int nice_rlim
= 20 - nice
;
4625 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
4626 capable(CAP_SYS_NICE
));
4629 #ifdef __ARCH_WANT_SYS_NICE
4632 * sys_nice - change the priority of the current process.
4633 * @increment: priority increment
4635 * sys_setpriority is a more generic, but much slower function that
4636 * does similar things.
4638 asmlinkage
long sys_nice(int increment
)
4643 * Setpriority might change our priority at the same moment.
4644 * We don't have to worry. Conceptually one call occurs first
4645 * and we have a single winner.
4647 if (increment
< -40)
4652 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
4658 if (increment
< 0 && !can_nice(current
, nice
))
4661 retval
= security_task_setnice(current
, nice
);
4665 set_user_nice(current
, nice
);
4672 * task_prio - return the priority value of a given task.
4673 * @p: the task in question.
4675 * This is the priority value as seen by users in /proc.
4676 * RT tasks are offset by -200. Normal tasks are centered
4677 * around 0, value goes from -16 to +15.
4679 int task_prio(const struct task_struct
*p
)
4681 return p
->prio
- MAX_RT_PRIO
;
4685 * task_nice - return the nice value of a given task.
4686 * @p: the task in question.
4688 int task_nice(const struct task_struct
*p
)
4690 return TASK_NICE(p
);
4692 EXPORT_SYMBOL(task_nice
);
4695 * idle_cpu - is a given cpu idle currently?
4696 * @cpu: the processor in question.
4698 int idle_cpu(int cpu
)
4700 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
4704 * idle_task - return the idle task for a given cpu.
4705 * @cpu: the processor in question.
4707 struct task_struct
*idle_task(int cpu
)
4709 return cpu_rq(cpu
)->idle
;
4713 * find_process_by_pid - find a process with a matching PID value.
4714 * @pid: the pid in question.
4716 static struct task_struct
*find_process_by_pid(pid_t pid
)
4718 return pid
? find_task_by_vpid(pid
) : current
;
4721 /* Actually do priority change: must hold rq lock. */
4723 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
4725 BUG_ON(p
->se
.on_rq
);
4728 switch (p
->policy
) {
4732 p
->sched_class
= &fair_sched_class
;
4736 p
->sched_class
= &rt_sched_class
;
4740 p
->rt_priority
= prio
;
4741 p
->normal_prio
= normal_prio(p
);
4742 /* we are holding p->pi_lock already */
4743 p
->prio
= rt_mutex_getprio(p
);
4748 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
4749 * @p: the task in question.
4750 * @policy: new policy.
4751 * @param: structure containing the new RT priority.
4753 * NOTE that the task may be already dead.
4755 int sched_setscheduler(struct task_struct
*p
, int policy
,
4756 struct sched_param
*param
)
4758 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
4759 unsigned long flags
;
4760 const struct sched_class
*prev_class
= p
->sched_class
;
4763 /* may grab non-irq protected spin_locks */
4764 BUG_ON(in_interrupt());
4766 /* double check policy once rq lock held */
4768 policy
= oldpolicy
= p
->policy
;
4769 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
4770 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
4771 policy
!= SCHED_IDLE
)
4774 * Valid priorities for SCHED_FIFO and SCHED_RR are
4775 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4776 * SCHED_BATCH and SCHED_IDLE is 0.
4778 if (param
->sched_priority
< 0 ||
4779 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
4780 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
4782 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
4786 * Allow unprivileged RT tasks to decrease priority:
4788 if (!capable(CAP_SYS_NICE
)) {
4789 if (rt_policy(policy
)) {
4790 unsigned long rlim_rtprio
;
4792 if (!lock_task_sighand(p
, &flags
))
4794 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
4795 unlock_task_sighand(p
, &flags
);
4797 /* can't set/change the rt policy */
4798 if (policy
!= p
->policy
&& !rlim_rtprio
)
4801 /* can't increase priority */
4802 if (param
->sched_priority
> p
->rt_priority
&&
4803 param
->sched_priority
> rlim_rtprio
)
4807 * Like positive nice levels, dont allow tasks to
4808 * move out of SCHED_IDLE either:
4810 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
4813 /* can't change other user's priorities */
4814 if ((current
->euid
!= p
->euid
) &&
4815 (current
->euid
!= p
->uid
))
4819 #ifdef CONFIG_RT_GROUP_SCHED
4821 * Do not allow realtime tasks into groups that have no runtime
4824 if (rt_policy(policy
) && task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
4828 retval
= security_task_setscheduler(p
, policy
, param
);
4832 * make sure no PI-waiters arrive (or leave) while we are
4833 * changing the priority of the task:
4835 spin_lock_irqsave(&p
->pi_lock
, flags
);
4837 * To be able to change p->policy safely, the apropriate
4838 * runqueue lock must be held.
4840 rq
= __task_rq_lock(p
);
4841 /* recheck policy now with rq lock held */
4842 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
4843 policy
= oldpolicy
= -1;
4844 __task_rq_unlock(rq
);
4845 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4848 update_rq_clock(rq
);
4849 on_rq
= p
->se
.on_rq
;
4850 running
= task_current(rq
, p
);
4852 deactivate_task(rq
, p
, 0);
4854 p
->sched_class
->put_prev_task(rq
, p
);
4857 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
4860 p
->sched_class
->set_curr_task(rq
);
4862 activate_task(rq
, p
, 0);
4864 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
4866 __task_rq_unlock(rq
);
4867 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
4869 rt_mutex_adjust_pi(p
);
4873 EXPORT_SYMBOL_GPL(sched_setscheduler
);
4876 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4878 struct sched_param lparam
;
4879 struct task_struct
*p
;
4882 if (!param
|| pid
< 0)
4884 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
4889 p
= find_process_by_pid(pid
);
4891 retval
= sched_setscheduler(p
, policy
, &lparam
);
4898 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4899 * @pid: the pid in question.
4900 * @policy: new policy.
4901 * @param: structure containing the new RT priority.
4904 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
4906 /* negative values for policy are not valid */
4910 return do_sched_setscheduler(pid
, policy
, param
);
4914 * sys_sched_setparam - set/change the RT priority of a thread
4915 * @pid: the pid in question.
4916 * @param: structure containing the new RT priority.
4918 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
4920 return do_sched_setscheduler(pid
, -1, param
);
4924 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4925 * @pid: the pid in question.
4927 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
4929 struct task_struct
*p
;
4936 read_lock(&tasklist_lock
);
4937 p
= find_process_by_pid(pid
);
4939 retval
= security_task_getscheduler(p
);
4943 read_unlock(&tasklist_lock
);
4948 * sys_sched_getscheduler - get the RT priority of a thread
4949 * @pid: the pid in question.
4950 * @param: structure containing the RT priority.
4952 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
4954 struct sched_param lp
;
4955 struct task_struct
*p
;
4958 if (!param
|| pid
< 0)
4961 read_lock(&tasklist_lock
);
4962 p
= find_process_by_pid(pid
);
4967 retval
= security_task_getscheduler(p
);
4971 lp
.sched_priority
= p
->rt_priority
;
4972 read_unlock(&tasklist_lock
);
4975 * This one might sleep, we cannot do it with a spinlock held ...
4977 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
4982 read_unlock(&tasklist_lock
);
4986 long sched_setaffinity(pid_t pid
, const cpumask_t
*in_mask
)
4988 cpumask_t cpus_allowed
;
4989 cpumask_t new_mask
= *in_mask
;
4990 struct task_struct
*p
;
4994 read_lock(&tasklist_lock
);
4996 p
= find_process_by_pid(pid
);
4998 read_unlock(&tasklist_lock
);
5004 * It is not safe to call set_cpus_allowed with the
5005 * tasklist_lock held. We will bump the task_struct's
5006 * usage count and then drop tasklist_lock.
5009 read_unlock(&tasklist_lock
);
5012 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
5013 !capable(CAP_SYS_NICE
))
5016 retval
= security_task_setscheduler(p
, 0, NULL
);
5020 cpuset_cpus_allowed(p
, &cpus_allowed
);
5021 cpus_and(new_mask
, new_mask
, cpus_allowed
);
5023 retval
= set_cpus_allowed_ptr(p
, &new_mask
);
5026 cpuset_cpus_allowed(p
, &cpus_allowed
);
5027 if (!cpus_subset(new_mask
, cpus_allowed
)) {
5029 * We must have raced with a concurrent cpuset
5030 * update. Just reset the cpus_allowed to the
5031 * cpuset's cpus_allowed
5033 new_mask
= cpus_allowed
;
5043 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5044 cpumask_t
*new_mask
)
5046 if (len
< sizeof(cpumask_t
)) {
5047 memset(new_mask
, 0, sizeof(cpumask_t
));
5048 } else if (len
> sizeof(cpumask_t
)) {
5049 len
= sizeof(cpumask_t
);
5051 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5055 * sys_sched_setaffinity - set the cpu affinity of a process
5056 * @pid: pid of the process
5057 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5058 * @user_mask_ptr: user-space pointer to the new cpu mask
5060 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
5061 unsigned long __user
*user_mask_ptr
)
5066 retval
= get_user_cpu_mask(user_mask_ptr
, len
, &new_mask
);
5070 return sched_setaffinity(pid
, &new_mask
);
5074 * Represents all cpu's present in the system
5075 * In systems capable of hotplug, this map could dynamically grow
5076 * as new cpu's are detected in the system via any platform specific
5077 * method, such as ACPI for e.g.
5080 cpumask_t cpu_present_map __read_mostly
;
5081 EXPORT_SYMBOL(cpu_present_map
);
5084 cpumask_t cpu_online_map __read_mostly
= CPU_MASK_ALL
;
5085 EXPORT_SYMBOL(cpu_online_map
);
5087 cpumask_t cpu_possible_map __read_mostly
= CPU_MASK_ALL
;
5088 EXPORT_SYMBOL(cpu_possible_map
);
5091 long sched_getaffinity(pid_t pid
, cpumask_t
*mask
)
5093 struct task_struct
*p
;
5097 read_lock(&tasklist_lock
);
5100 p
= find_process_by_pid(pid
);
5104 retval
= security_task_getscheduler(p
);
5108 cpus_and(*mask
, p
->cpus_allowed
, cpu_online_map
);
5111 read_unlock(&tasklist_lock
);
5118 * sys_sched_getaffinity - get the cpu affinity of a process
5119 * @pid: pid of the process
5120 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5121 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5123 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5124 unsigned long __user
*user_mask_ptr
)
5129 if (len
< sizeof(cpumask_t
))
5132 ret
= sched_getaffinity(pid
, &mask
);
5136 if (copy_to_user(user_mask_ptr
, &mask
, sizeof(cpumask_t
)))
5139 return sizeof(cpumask_t
);
5143 * sys_sched_yield - yield the current processor to other threads.
5145 * This function yields the current CPU to other tasks. If there are no
5146 * other threads running on this CPU then this function will return.
5148 asmlinkage
long sys_sched_yield(void)
5150 struct rq
*rq
= this_rq_lock();
5152 schedstat_inc(rq
, yld_count
);
5153 current
->sched_class
->yield_task(rq
);
5156 * Since we are going to call schedule() anyway, there's
5157 * no need to preempt or enable interrupts:
5159 __release(rq
->lock
);
5160 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5161 _raw_spin_unlock(&rq
->lock
);
5162 preempt_enable_no_resched();
5169 static void __cond_resched(void)
5171 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5172 __might_sleep(__FILE__
, __LINE__
);
5175 * The BKS might be reacquired before we have dropped
5176 * PREEMPT_ACTIVE, which could trigger a second
5177 * cond_resched() call.
5180 add_preempt_count(PREEMPT_ACTIVE
);
5182 sub_preempt_count(PREEMPT_ACTIVE
);
5183 } while (need_resched());
5186 int __sched
_cond_resched(void)
5188 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5189 system_state
== SYSTEM_RUNNING
) {
5195 EXPORT_SYMBOL(_cond_resched
);
5198 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5199 * call schedule, and on return reacquire the lock.
5201 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5202 * operations here to prevent schedule() from being called twice (once via
5203 * spin_unlock(), once by hand).
5205 int cond_resched_lock(spinlock_t
*lock
)
5207 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5210 if (spin_needbreak(lock
) || resched
) {
5212 if (resched
&& need_resched())
5221 EXPORT_SYMBOL(cond_resched_lock
);
5223 int __sched
cond_resched_softirq(void)
5225 BUG_ON(!in_softirq());
5227 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5235 EXPORT_SYMBOL(cond_resched_softirq
);
5238 * yield - yield the current processor to other threads.
5240 * This is a shortcut for kernel-space yielding - it marks the
5241 * thread runnable and calls sys_sched_yield().
5243 void __sched
yield(void)
5245 set_current_state(TASK_RUNNING
);
5248 EXPORT_SYMBOL(yield
);
5251 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5252 * that process accounting knows that this is a task in IO wait state.
5254 * But don't do that if it is a deliberate, throttling IO wait (this task
5255 * has set its backing_dev_info: the queue against which it should throttle)
5257 void __sched
io_schedule(void)
5259 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5261 delayacct_blkio_start();
5262 atomic_inc(&rq
->nr_iowait
);
5264 atomic_dec(&rq
->nr_iowait
);
5265 delayacct_blkio_end();
5267 EXPORT_SYMBOL(io_schedule
);
5269 long __sched
io_schedule_timeout(long timeout
)
5271 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5274 delayacct_blkio_start();
5275 atomic_inc(&rq
->nr_iowait
);
5276 ret
= schedule_timeout(timeout
);
5277 atomic_dec(&rq
->nr_iowait
);
5278 delayacct_blkio_end();
5283 * sys_sched_get_priority_max - return maximum RT priority.
5284 * @policy: scheduling class.
5286 * this syscall returns the maximum rt_priority that can be used
5287 * by a given scheduling class.
5289 asmlinkage
long sys_sched_get_priority_max(int policy
)
5296 ret
= MAX_USER_RT_PRIO
-1;
5308 * sys_sched_get_priority_min - return minimum RT priority.
5309 * @policy: scheduling class.
5311 * this syscall returns the minimum rt_priority that can be used
5312 * by a given scheduling class.
5314 asmlinkage
long sys_sched_get_priority_min(int policy
)
5332 * sys_sched_rr_get_interval - return the default timeslice of a process.
5333 * @pid: pid of the process.
5334 * @interval: userspace pointer to the timeslice value.
5336 * this syscall writes the default timeslice value of a given process
5337 * into the user-space timespec buffer. A value of '0' means infinity.
5340 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5342 struct task_struct
*p
;
5343 unsigned int time_slice
;
5351 read_lock(&tasklist_lock
);
5352 p
= find_process_by_pid(pid
);
5356 retval
= security_task_getscheduler(p
);
5361 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5362 * tasks that are on an otherwise idle runqueue:
5365 if (p
->policy
== SCHED_RR
) {
5366 time_slice
= DEF_TIMESLICE
;
5367 } else if (p
->policy
!= SCHED_FIFO
) {
5368 struct sched_entity
*se
= &p
->se
;
5369 unsigned long flags
;
5372 rq
= task_rq_lock(p
, &flags
);
5373 if (rq
->cfs
.load
.weight
)
5374 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5375 task_rq_unlock(rq
, &flags
);
5377 read_unlock(&tasklist_lock
);
5378 jiffies_to_timespec(time_slice
, &t
);
5379 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5383 read_unlock(&tasklist_lock
);
5387 static const char stat_nam
[] = "RSDTtZX";
5389 void sched_show_task(struct task_struct
*p
)
5391 unsigned long free
= 0;
5394 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5395 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5396 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5397 #if BITS_PER_LONG == 32
5398 if (state
== TASK_RUNNING
)
5399 printk(KERN_CONT
" running ");
5401 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5403 if (state
== TASK_RUNNING
)
5404 printk(KERN_CONT
" running task ");
5406 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5408 #ifdef CONFIG_DEBUG_STACK_USAGE
5410 unsigned long *n
= end_of_stack(p
);
5413 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
5416 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
5417 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
5419 show_stack(p
, NULL
);
5422 void show_state_filter(unsigned long state_filter
)
5424 struct task_struct
*g
, *p
;
5426 #if BITS_PER_LONG == 32
5428 " task PC stack pid father\n");
5431 " task PC stack pid father\n");
5433 read_lock(&tasklist_lock
);
5434 do_each_thread(g
, p
) {
5436 * reset the NMI-timeout, listing all files on a slow
5437 * console might take alot of time:
5439 touch_nmi_watchdog();
5440 if (!state_filter
|| (p
->state
& state_filter
))
5442 } while_each_thread(g
, p
);
5444 touch_all_softlockup_watchdogs();
5446 #ifdef CONFIG_SCHED_DEBUG
5447 sysrq_sched_debug_show();
5449 read_unlock(&tasklist_lock
);
5451 * Only show locks if all tasks are dumped:
5453 if (state_filter
== -1)
5454 debug_show_all_locks();
5457 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5459 idle
->sched_class
= &idle_sched_class
;
5463 * init_idle - set up an idle thread for a given CPU
5464 * @idle: task in question
5465 * @cpu: cpu the idle task belongs to
5467 * NOTE: this function does not set the idle thread's NEED_RESCHED
5468 * flag, to make booting more robust.
5470 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5472 struct rq
*rq
= cpu_rq(cpu
);
5473 unsigned long flags
;
5476 idle
->se
.exec_start
= sched_clock();
5478 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
5479 idle
->cpus_allowed
= cpumask_of_cpu(cpu
);
5480 __set_task_cpu(idle
, cpu
);
5482 spin_lock_irqsave(&rq
->lock
, flags
);
5483 rq
->curr
= rq
->idle
= idle
;
5484 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5487 spin_unlock_irqrestore(&rq
->lock
, flags
);
5489 /* Set the preempt count _outside_ the spinlocks! */
5490 #if defined(CONFIG_PREEMPT)
5491 task_thread_info(idle
)->preempt_count
= (idle
->lock_depth
>= 0);
5493 task_thread_info(idle
)->preempt_count
= 0;
5496 * The idle tasks have their own, simple scheduling class:
5498 idle
->sched_class
= &idle_sched_class
;
5502 * In a system that switches off the HZ timer nohz_cpu_mask
5503 * indicates which cpus entered this state. This is used
5504 * in the rcu update to wait only for active cpus. For system
5505 * which do not switch off the HZ timer nohz_cpu_mask should
5506 * always be CPU_MASK_NONE.
5508 cpumask_t nohz_cpu_mask
= CPU_MASK_NONE
;
5511 * Increase the granularity value when there are more CPUs,
5512 * because with more CPUs the 'effective latency' as visible
5513 * to users decreases. But the relationship is not linear,
5514 * so pick a second-best guess by going with the log2 of the
5517 * This idea comes from the SD scheduler of Con Kolivas:
5519 static inline void sched_init_granularity(void)
5521 unsigned int factor
= 1 + ilog2(num_online_cpus());
5522 const unsigned long limit
= 200000000;
5524 sysctl_sched_min_granularity
*= factor
;
5525 if (sysctl_sched_min_granularity
> limit
)
5526 sysctl_sched_min_granularity
= limit
;
5528 sysctl_sched_latency
*= factor
;
5529 if (sysctl_sched_latency
> limit
)
5530 sysctl_sched_latency
= limit
;
5532 sysctl_sched_wakeup_granularity
*= factor
;
5537 * This is how migration works:
5539 * 1) we queue a struct migration_req structure in the source CPU's
5540 * runqueue and wake up that CPU's migration thread.
5541 * 2) we down() the locked semaphore => thread blocks.
5542 * 3) migration thread wakes up (implicitly it forces the migrated
5543 * thread off the CPU)
5544 * 4) it gets the migration request and checks whether the migrated
5545 * task is still in the wrong runqueue.
5546 * 5) if it's in the wrong runqueue then the migration thread removes
5547 * it and puts it into the right queue.
5548 * 6) migration thread up()s the semaphore.
5549 * 7) we wake up and the migration is done.
5553 * Change a given task's CPU affinity. Migrate the thread to a
5554 * proper CPU and schedule it away if the CPU it's executing on
5555 * is removed from the allowed bitmask.
5557 * NOTE: the caller must have a valid reference to the task, the
5558 * task must not exit() & deallocate itself prematurely. The
5559 * call is not atomic; no spinlocks may be held.
5561 int set_cpus_allowed_ptr(struct task_struct
*p
, const cpumask_t
*new_mask
)
5563 struct migration_req req
;
5564 unsigned long flags
;
5568 rq
= task_rq_lock(p
, &flags
);
5569 if (!cpus_intersects(*new_mask
, cpu_online_map
)) {
5574 if (p
->sched_class
->set_cpus_allowed
)
5575 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
5577 p
->cpus_allowed
= *new_mask
;
5578 p
->rt
.nr_cpus_allowed
= cpus_weight(*new_mask
);
5581 /* Can the task run on the task's current CPU? If so, we're done */
5582 if (cpu_isset(task_cpu(p
), *new_mask
))
5585 if (migrate_task(p
, any_online_cpu(*new_mask
), &req
)) {
5586 /* Need help from migration thread: drop lock and wait. */
5587 task_rq_unlock(rq
, &flags
);
5588 wake_up_process(rq
->migration_thread
);
5589 wait_for_completion(&req
.done
);
5590 tlb_migrate_finish(p
->mm
);
5594 task_rq_unlock(rq
, &flags
);
5598 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
5601 * Move (not current) task off this cpu, onto dest cpu. We're doing
5602 * this because either it can't run here any more (set_cpus_allowed()
5603 * away from this CPU, or CPU going down), or because we're
5604 * attempting to rebalance this task on exec (sched_exec).
5606 * So we race with normal scheduler movements, but that's OK, as long
5607 * as the task is no longer on this CPU.
5609 * Returns non-zero if task was successfully migrated.
5611 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5613 struct rq
*rq_dest
, *rq_src
;
5616 if (unlikely(cpu_is_offline(dest_cpu
)))
5619 rq_src
= cpu_rq(src_cpu
);
5620 rq_dest
= cpu_rq(dest_cpu
);
5622 double_rq_lock(rq_src
, rq_dest
);
5623 /* Already moved. */
5624 if (task_cpu(p
) != src_cpu
)
5626 /* Affinity changed (again). */
5627 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
))
5630 on_rq
= p
->se
.on_rq
;
5632 deactivate_task(rq_src
, p
, 0);
5634 set_task_cpu(p
, dest_cpu
);
5636 activate_task(rq_dest
, p
, 0);
5637 check_preempt_curr(rq_dest
, p
);
5642 double_rq_unlock(rq_src
, rq_dest
);
5647 * migration_thread - this is a highprio system thread that performs
5648 * thread migration by bumping thread off CPU then 'pushing' onto
5651 static int migration_thread(void *data
)
5653 int cpu
= (long)data
;
5657 BUG_ON(rq
->migration_thread
!= current
);
5659 set_current_state(TASK_INTERRUPTIBLE
);
5660 while (!kthread_should_stop()) {
5661 struct migration_req
*req
;
5662 struct list_head
*head
;
5664 spin_lock_irq(&rq
->lock
);
5666 if (cpu_is_offline(cpu
)) {
5667 spin_unlock_irq(&rq
->lock
);
5671 if (rq
->active_balance
) {
5672 active_load_balance(rq
, cpu
);
5673 rq
->active_balance
= 0;
5676 head
= &rq
->migration_queue
;
5678 if (list_empty(head
)) {
5679 spin_unlock_irq(&rq
->lock
);
5681 set_current_state(TASK_INTERRUPTIBLE
);
5684 req
= list_entry(head
->next
, struct migration_req
, list
);
5685 list_del_init(head
->next
);
5687 spin_unlock(&rq
->lock
);
5688 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
5691 complete(&req
->done
);
5693 __set_current_state(TASK_RUNNING
);
5697 /* Wait for kthread_stop */
5698 set_current_state(TASK_INTERRUPTIBLE
);
5699 while (!kthread_should_stop()) {
5701 set_current_state(TASK_INTERRUPTIBLE
);
5703 __set_current_state(TASK_RUNNING
);
5707 #ifdef CONFIG_HOTPLUG_CPU
5709 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
5713 local_irq_disable();
5714 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
5720 * Figure out where task on dead CPU should go, use force if necessary.
5721 * NOTE: interrupts should be disabled by the caller
5723 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
5725 unsigned long flags
;
5732 mask
= node_to_cpumask(cpu_to_node(dead_cpu
));
5733 cpus_and(mask
, mask
, p
->cpus_allowed
);
5734 dest_cpu
= any_online_cpu(mask
);
5736 /* On any allowed CPU? */
5737 if (dest_cpu
>= nr_cpu_ids
)
5738 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5740 /* No more Mr. Nice Guy. */
5741 if (dest_cpu
>= nr_cpu_ids
) {
5742 cpumask_t cpus_allowed
;
5744 cpuset_cpus_allowed_locked(p
, &cpus_allowed
);
5746 * Try to stay on the same cpuset, where the
5747 * current cpuset may be a subset of all cpus.
5748 * The cpuset_cpus_allowed_locked() variant of
5749 * cpuset_cpus_allowed() will not block. It must be
5750 * called within calls to cpuset_lock/cpuset_unlock.
5752 rq
= task_rq_lock(p
, &flags
);
5753 p
->cpus_allowed
= cpus_allowed
;
5754 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
5755 task_rq_unlock(rq
, &flags
);
5758 * Don't tell them about moving exiting tasks or
5759 * kernel threads (both mm NULL), since they never
5762 if (p
->mm
&& printk_ratelimit()) {
5763 printk(KERN_INFO
"process %d (%s) no "
5764 "longer affine to cpu%d\n",
5765 task_pid_nr(p
), p
->comm
, dead_cpu
);
5768 } while (!__migrate_task_irq(p
, dead_cpu
, dest_cpu
));
5772 * While a dead CPU has no uninterruptible tasks queued at this point,
5773 * it might still have a nonzero ->nr_uninterruptible counter, because
5774 * for performance reasons the counter is not stricly tracking tasks to
5775 * their home CPUs. So we just add the counter to another CPU's counter,
5776 * to keep the global sum constant after CPU-down:
5778 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
5780 struct rq
*rq_dest
= cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR
));
5781 unsigned long flags
;
5783 local_irq_save(flags
);
5784 double_rq_lock(rq_src
, rq_dest
);
5785 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
5786 rq_src
->nr_uninterruptible
= 0;
5787 double_rq_unlock(rq_src
, rq_dest
);
5788 local_irq_restore(flags
);
5791 /* Run through task list and migrate tasks from the dead cpu. */
5792 static void migrate_live_tasks(int src_cpu
)
5794 struct task_struct
*p
, *t
;
5796 read_lock(&tasklist_lock
);
5798 do_each_thread(t
, p
) {
5802 if (task_cpu(p
) == src_cpu
)
5803 move_task_off_dead_cpu(src_cpu
, p
);
5804 } while_each_thread(t
, p
);
5806 read_unlock(&tasklist_lock
);
5810 * Schedules idle task to be the next runnable task on current CPU.
5811 * It does so by boosting its priority to highest possible.
5812 * Used by CPU offline code.
5814 void sched_idle_next(void)
5816 int this_cpu
= smp_processor_id();
5817 struct rq
*rq
= cpu_rq(this_cpu
);
5818 struct task_struct
*p
= rq
->idle
;
5819 unsigned long flags
;
5821 /* cpu has to be offline */
5822 BUG_ON(cpu_online(this_cpu
));
5825 * Strictly not necessary since rest of the CPUs are stopped by now
5826 * and interrupts disabled on the current cpu.
5828 spin_lock_irqsave(&rq
->lock
, flags
);
5830 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
5832 update_rq_clock(rq
);
5833 activate_task(rq
, p
, 0);
5835 spin_unlock_irqrestore(&rq
->lock
, flags
);
5839 * Ensures that the idle task is using init_mm right before its cpu goes
5842 void idle_task_exit(void)
5844 struct mm_struct
*mm
= current
->active_mm
;
5846 BUG_ON(cpu_online(smp_processor_id()));
5849 switch_mm(mm
, &init_mm
, current
);
5853 /* called under rq->lock with disabled interrupts */
5854 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
5856 struct rq
*rq
= cpu_rq(dead_cpu
);
5858 /* Must be exiting, otherwise would be on tasklist. */
5859 BUG_ON(!p
->exit_state
);
5861 /* Cannot have done final schedule yet: would have vanished. */
5862 BUG_ON(p
->state
== TASK_DEAD
);
5867 * Drop lock around migration; if someone else moves it,
5868 * that's OK. No task can be added to this CPU, so iteration is
5871 spin_unlock_irq(&rq
->lock
);
5872 move_task_off_dead_cpu(dead_cpu
, p
);
5873 spin_lock_irq(&rq
->lock
);
5878 /* release_task() removes task from tasklist, so we won't find dead tasks. */
5879 static void migrate_dead_tasks(unsigned int dead_cpu
)
5881 struct rq
*rq
= cpu_rq(dead_cpu
);
5882 struct task_struct
*next
;
5885 if (!rq
->nr_running
)
5887 update_rq_clock(rq
);
5888 next
= pick_next_task(rq
, rq
->curr
);
5891 next
->sched_class
->put_prev_task(rq
, next
);
5892 migrate_dead(dead_cpu
, next
);
5896 #endif /* CONFIG_HOTPLUG_CPU */
5898 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5900 static struct ctl_table sd_ctl_dir
[] = {
5902 .procname
= "sched_domain",
5908 static struct ctl_table sd_ctl_root
[] = {
5910 .ctl_name
= CTL_KERN
,
5911 .procname
= "kernel",
5913 .child
= sd_ctl_dir
,
5918 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
5920 struct ctl_table
*entry
=
5921 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
5926 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
5928 struct ctl_table
*entry
;
5931 * In the intermediate directories, both the child directory and
5932 * procname are dynamically allocated and could fail but the mode
5933 * will always be set. In the lowest directory the names are
5934 * static strings and all have proc handlers.
5936 for (entry
= *tablep
; entry
->mode
; entry
++) {
5938 sd_free_ctl_entry(&entry
->child
);
5939 if (entry
->proc_handler
== NULL
)
5940 kfree(entry
->procname
);
5948 set_table_entry(struct ctl_table
*entry
,
5949 const char *procname
, void *data
, int maxlen
,
5950 mode_t mode
, proc_handler
*proc_handler
)
5952 entry
->procname
= procname
;
5954 entry
->maxlen
= maxlen
;
5956 entry
->proc_handler
= proc_handler
;
5959 static struct ctl_table
*
5960 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
5962 struct ctl_table
*table
= sd_alloc_ctl_entry(12);
5967 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
5968 sizeof(long), 0644, proc_doulongvec_minmax
);
5969 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
5970 sizeof(long), 0644, proc_doulongvec_minmax
);
5971 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
5972 sizeof(int), 0644, proc_dointvec_minmax
);
5973 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
5974 sizeof(int), 0644, proc_dointvec_minmax
);
5975 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
5976 sizeof(int), 0644, proc_dointvec_minmax
);
5977 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
5978 sizeof(int), 0644, proc_dointvec_minmax
);
5979 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
5980 sizeof(int), 0644, proc_dointvec_minmax
);
5981 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
5982 sizeof(int), 0644, proc_dointvec_minmax
);
5983 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
5984 sizeof(int), 0644, proc_dointvec_minmax
);
5985 set_table_entry(&table
[9], "cache_nice_tries",
5986 &sd
->cache_nice_tries
,
5987 sizeof(int), 0644, proc_dointvec_minmax
);
5988 set_table_entry(&table
[10], "flags", &sd
->flags
,
5989 sizeof(int), 0644, proc_dointvec_minmax
);
5990 /* &table[11] is terminator */
5995 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
5997 struct ctl_table
*entry
, *table
;
5998 struct sched_domain
*sd
;
5999 int domain_num
= 0, i
;
6002 for_each_domain(cpu
, sd
)
6004 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6009 for_each_domain(cpu
, sd
) {
6010 snprintf(buf
, 32, "domain%d", i
);
6011 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6013 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6020 static struct ctl_table_header
*sd_sysctl_header
;
6021 static void register_sched_domain_sysctl(void)
6023 int i
, cpu_num
= num_online_cpus();
6024 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6027 WARN_ON(sd_ctl_dir
[0].child
);
6028 sd_ctl_dir
[0].child
= entry
;
6033 for_each_online_cpu(i
) {
6034 snprintf(buf
, 32, "cpu%d", i
);
6035 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6037 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6041 WARN_ON(sd_sysctl_header
);
6042 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6045 /* may be called multiple times per register */
6046 static void unregister_sched_domain_sysctl(void)
6048 if (sd_sysctl_header
)
6049 unregister_sysctl_table(sd_sysctl_header
);
6050 sd_sysctl_header
= NULL
;
6051 if (sd_ctl_dir
[0].child
)
6052 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6055 static void register_sched_domain_sysctl(void)
6058 static void unregister_sched_domain_sysctl(void)
6064 * migration_call - callback that gets triggered when a CPU is added.
6065 * Here we can start up the necessary migration thread for the new CPU.
6067 static int __cpuinit
6068 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6070 struct task_struct
*p
;
6071 int cpu
= (long)hcpu
;
6072 unsigned long flags
;
6077 case CPU_UP_PREPARE
:
6078 case CPU_UP_PREPARE_FROZEN
:
6079 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6082 kthread_bind(p
, cpu
);
6083 /* Must be high prio: stop_machine expects to yield to it. */
6084 rq
= task_rq_lock(p
, &flags
);
6085 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6086 task_rq_unlock(rq
, &flags
);
6087 cpu_rq(cpu
)->migration_thread
= p
;
6091 case CPU_ONLINE_FROZEN
:
6092 /* Strictly unnecessary, as first user will wake it. */
6093 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6095 /* Update our root-domain */
6097 spin_lock_irqsave(&rq
->lock
, flags
);
6099 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6100 cpu_set(cpu
, rq
->rd
->online
);
6102 spin_unlock_irqrestore(&rq
->lock
, flags
);
6105 #ifdef CONFIG_HOTPLUG_CPU
6106 case CPU_UP_CANCELED
:
6107 case CPU_UP_CANCELED_FROZEN
:
6108 if (!cpu_rq(cpu
)->migration_thread
)
6110 /* Unbind it from offline cpu so it can run. Fall thru. */
6111 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6112 any_online_cpu(cpu_online_map
));
6113 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6114 cpu_rq(cpu
)->migration_thread
= NULL
;
6118 case CPU_DEAD_FROZEN
:
6119 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6120 migrate_live_tasks(cpu
);
6122 kthread_stop(rq
->migration_thread
);
6123 rq
->migration_thread
= NULL
;
6124 /* Idle task back to normal (off runqueue, low prio) */
6125 spin_lock_irq(&rq
->lock
);
6126 update_rq_clock(rq
);
6127 deactivate_task(rq
, rq
->idle
, 0);
6128 rq
->idle
->static_prio
= MAX_PRIO
;
6129 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6130 rq
->idle
->sched_class
= &idle_sched_class
;
6131 migrate_dead_tasks(cpu
);
6132 spin_unlock_irq(&rq
->lock
);
6134 migrate_nr_uninterruptible(rq
);
6135 BUG_ON(rq
->nr_running
!= 0);
6138 * No need to migrate the tasks: it was best-effort if
6139 * they didn't take sched_hotcpu_mutex. Just wake up
6142 spin_lock_irq(&rq
->lock
);
6143 while (!list_empty(&rq
->migration_queue
)) {
6144 struct migration_req
*req
;
6146 req
= list_entry(rq
->migration_queue
.next
,
6147 struct migration_req
, list
);
6148 list_del_init(&req
->list
);
6149 complete(&req
->done
);
6151 spin_unlock_irq(&rq
->lock
);
6155 case CPU_DYING_FROZEN
:
6156 /* Update our root-domain */
6158 spin_lock_irqsave(&rq
->lock
, flags
);
6160 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6161 cpu_clear(cpu
, rq
->rd
->online
);
6163 spin_unlock_irqrestore(&rq
->lock
, flags
);
6170 /* Register at highest priority so that task migration (migrate_all_tasks)
6171 * happens before everything else.
6173 static struct notifier_block __cpuinitdata migration_notifier
= {
6174 .notifier_call
= migration_call
,
6178 void __init
migration_init(void)
6180 void *cpu
= (void *)(long)smp_processor_id();
6183 /* Start one for the boot CPU: */
6184 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6185 BUG_ON(err
== NOTIFY_BAD
);
6186 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6187 register_cpu_notifier(&migration_notifier
);
6193 #ifdef CONFIG_SCHED_DEBUG
6195 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6196 cpumask_t
*groupmask
)
6198 struct sched_group
*group
= sd
->groups
;
6201 cpulist_scnprintf(str
, sizeof(str
), sd
->span
);
6202 cpus_clear(*groupmask
);
6204 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6206 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6207 printk("does not load-balance\n");
6209 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6214 printk(KERN_CONT
"span %s\n", str
);
6216 if (!cpu_isset(cpu
, sd
->span
)) {
6217 printk(KERN_ERR
"ERROR: domain->span does not contain "
6220 if (!cpu_isset(cpu
, group
->cpumask
)) {
6221 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6225 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6229 printk(KERN_ERR
"ERROR: group is NULL\n");
6233 if (!group
->__cpu_power
) {
6234 printk(KERN_CONT
"\n");
6235 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6240 if (!cpus_weight(group
->cpumask
)) {
6241 printk(KERN_CONT
"\n");
6242 printk(KERN_ERR
"ERROR: empty group\n");
6246 if (cpus_intersects(*groupmask
, group
->cpumask
)) {
6247 printk(KERN_CONT
"\n");
6248 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6252 cpus_or(*groupmask
, *groupmask
, group
->cpumask
);
6254 cpulist_scnprintf(str
, sizeof(str
), group
->cpumask
);
6255 printk(KERN_CONT
" %s", str
);
6257 group
= group
->next
;
6258 } while (group
!= sd
->groups
);
6259 printk(KERN_CONT
"\n");
6261 if (!cpus_equal(sd
->span
, *groupmask
))
6262 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6264 if (sd
->parent
&& !cpus_subset(*groupmask
, sd
->parent
->span
))
6265 printk(KERN_ERR
"ERROR: parent span is not a superset "
6266 "of domain->span\n");
6270 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6272 cpumask_t
*groupmask
;
6276 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6280 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6282 groupmask
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
6284 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6289 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6299 # define sched_domain_debug(sd, cpu) do { } while (0)
6302 static int sd_degenerate(struct sched_domain
*sd
)
6304 if (cpus_weight(sd
->span
) == 1)
6307 /* Following flags need at least 2 groups */
6308 if (sd
->flags
& (SD_LOAD_BALANCE
|
6309 SD_BALANCE_NEWIDLE
|
6313 SD_SHARE_PKG_RESOURCES
)) {
6314 if (sd
->groups
!= sd
->groups
->next
)
6318 /* Following flags don't use groups */
6319 if (sd
->flags
& (SD_WAKE_IDLE
|
6328 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6330 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6332 if (sd_degenerate(parent
))
6335 if (!cpus_equal(sd
->span
, parent
->span
))
6338 /* Does parent contain flags not in child? */
6339 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6340 if (cflags
& SD_WAKE_AFFINE
)
6341 pflags
&= ~SD_WAKE_BALANCE
;
6342 /* Flags needing groups don't count if only 1 group in parent */
6343 if (parent
->groups
== parent
->groups
->next
) {
6344 pflags
&= ~(SD_LOAD_BALANCE
|
6345 SD_BALANCE_NEWIDLE
|
6349 SD_SHARE_PKG_RESOURCES
);
6351 if (~cflags
& pflags
)
6357 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6359 unsigned long flags
;
6360 const struct sched_class
*class;
6362 spin_lock_irqsave(&rq
->lock
, flags
);
6365 struct root_domain
*old_rd
= rq
->rd
;
6367 for (class = sched_class_highest
; class; class = class->next
) {
6368 if (class->leave_domain
)
6369 class->leave_domain(rq
);
6372 cpu_clear(rq
->cpu
, old_rd
->span
);
6373 cpu_clear(rq
->cpu
, old_rd
->online
);
6375 if (atomic_dec_and_test(&old_rd
->refcount
))
6379 atomic_inc(&rd
->refcount
);
6382 cpu_set(rq
->cpu
, rd
->span
);
6383 if (cpu_isset(rq
->cpu
, cpu_online_map
))
6384 cpu_set(rq
->cpu
, rd
->online
);
6386 for (class = sched_class_highest
; class; class = class->next
) {
6387 if (class->join_domain
)
6388 class->join_domain(rq
);
6391 spin_unlock_irqrestore(&rq
->lock
, flags
);
6394 static void init_rootdomain(struct root_domain
*rd
)
6396 memset(rd
, 0, sizeof(*rd
));
6398 cpus_clear(rd
->span
);
6399 cpus_clear(rd
->online
);
6402 static void init_defrootdomain(void)
6404 init_rootdomain(&def_root_domain
);
6405 atomic_set(&def_root_domain
.refcount
, 1);
6408 static struct root_domain
*alloc_rootdomain(void)
6410 struct root_domain
*rd
;
6412 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6416 init_rootdomain(rd
);
6422 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6423 * hold the hotplug lock.
6426 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6428 struct rq
*rq
= cpu_rq(cpu
);
6429 struct sched_domain
*tmp
;
6431 /* Remove the sched domains which do not contribute to scheduling. */
6432 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
) {
6433 struct sched_domain
*parent
= tmp
->parent
;
6436 if (sd_parent_degenerate(tmp
, parent
)) {
6437 tmp
->parent
= parent
->parent
;
6439 parent
->parent
->child
= tmp
;
6443 if (sd
&& sd_degenerate(sd
)) {
6449 sched_domain_debug(sd
, cpu
);
6451 rq_attach_root(rq
, rd
);
6452 rcu_assign_pointer(rq
->sd
, sd
);
6455 /* cpus with isolated domains */
6456 static cpumask_t cpu_isolated_map
= CPU_MASK_NONE
;
6458 /* Setup the mask of cpus configured for isolated domains */
6459 static int __init
isolated_cpu_setup(char *str
)
6461 int ints
[NR_CPUS
], i
;
6463 str
= get_options(str
, ARRAY_SIZE(ints
), ints
);
6464 cpus_clear(cpu_isolated_map
);
6465 for (i
= 1; i
<= ints
[0]; i
++)
6466 if (ints
[i
] < NR_CPUS
)
6467 cpu_set(ints
[i
], cpu_isolated_map
);
6471 __setup("isolcpus=", isolated_cpu_setup
);
6474 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6475 * to a function which identifies what group(along with sched group) a CPU
6476 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6477 * (due to the fact that we keep track of groups covered with a cpumask_t).
6479 * init_sched_build_groups will build a circular linked list of the groups
6480 * covered by the given span, and will set each group's ->cpumask correctly,
6481 * and ->cpu_power to 0.
6484 init_sched_build_groups(const cpumask_t
*span
, const cpumask_t
*cpu_map
,
6485 int (*group_fn
)(int cpu
, const cpumask_t
*cpu_map
,
6486 struct sched_group
**sg
,
6487 cpumask_t
*tmpmask
),
6488 cpumask_t
*covered
, cpumask_t
*tmpmask
)
6490 struct sched_group
*first
= NULL
, *last
= NULL
;
6493 cpus_clear(*covered
);
6495 for_each_cpu_mask(i
, *span
) {
6496 struct sched_group
*sg
;
6497 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6500 if (cpu_isset(i
, *covered
))
6503 cpus_clear(sg
->cpumask
);
6504 sg
->__cpu_power
= 0;
6506 for_each_cpu_mask(j
, *span
) {
6507 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6510 cpu_set(j
, *covered
);
6511 cpu_set(j
, sg
->cpumask
);
6522 #define SD_NODES_PER_DOMAIN 16
6527 * find_next_best_node - find the next node to include in a sched_domain
6528 * @node: node whose sched_domain we're building
6529 * @used_nodes: nodes already in the sched_domain
6531 * Find the next node to include in a given scheduling domain. Simply
6532 * finds the closest node not already in the @used_nodes map.
6534 * Should use nodemask_t.
6536 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
6538 int i
, n
, val
, min_val
, best_node
= 0;
6542 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6543 /* Start at @node */
6544 n
= (node
+ i
) % MAX_NUMNODES
;
6546 if (!nr_cpus_node(n
))
6549 /* Skip already used nodes */
6550 if (node_isset(n
, *used_nodes
))
6553 /* Simple min distance search */
6554 val
= node_distance(node
, n
);
6556 if (val
< min_val
) {
6562 node_set(best_node
, *used_nodes
);
6567 * sched_domain_node_span - get a cpumask for a node's sched_domain
6568 * @node: node whose cpumask we're constructing
6569 * @span: resulting cpumask
6571 * Given a node, construct a good cpumask for its sched_domain to span. It
6572 * should be one that prevents unnecessary balancing, but also spreads tasks
6575 static void sched_domain_node_span(int node
, cpumask_t
*span
)
6577 nodemask_t used_nodes
;
6578 node_to_cpumask_ptr(nodemask
, node
);
6582 nodes_clear(used_nodes
);
6584 cpus_or(*span
, *span
, *nodemask
);
6585 node_set(node
, used_nodes
);
6587 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
6588 int next_node
= find_next_best_node(node
, &used_nodes
);
6590 node_to_cpumask_ptr_next(nodemask
, next_node
);
6591 cpus_or(*span
, *span
, *nodemask
);
6596 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
6599 * SMT sched-domains:
6601 #ifdef CONFIG_SCHED_SMT
6602 static DEFINE_PER_CPU(struct sched_domain
, cpu_domains
);
6603 static DEFINE_PER_CPU(struct sched_group
, sched_group_cpus
);
6606 cpu_to_cpu_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6610 *sg
= &per_cpu(sched_group_cpus
, cpu
);
6616 * multi-core sched-domains:
6618 #ifdef CONFIG_SCHED_MC
6619 static DEFINE_PER_CPU(struct sched_domain
, core_domains
);
6620 static DEFINE_PER_CPU(struct sched_group
, sched_group_core
);
6623 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
6625 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6630 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6631 cpus_and(*mask
, *mask
, *cpu_map
);
6632 group
= first_cpu(*mask
);
6634 *sg
= &per_cpu(sched_group_core
, group
);
6637 #elif defined(CONFIG_SCHED_MC)
6639 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6643 *sg
= &per_cpu(sched_group_core
, cpu
);
6648 static DEFINE_PER_CPU(struct sched_domain
, phys_domains
);
6649 static DEFINE_PER_CPU(struct sched_group
, sched_group_phys
);
6652 cpu_to_phys_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
6656 #ifdef CONFIG_SCHED_MC
6657 *mask
= cpu_coregroup_map(cpu
);
6658 cpus_and(*mask
, *mask
, *cpu_map
);
6659 group
= first_cpu(*mask
);
6660 #elif defined(CONFIG_SCHED_SMT)
6661 *mask
= per_cpu(cpu_sibling_map
, cpu
);
6662 cpus_and(*mask
, *mask
, *cpu_map
);
6663 group
= first_cpu(*mask
);
6668 *sg
= &per_cpu(sched_group_phys
, group
);
6674 * The init_sched_build_groups can't handle what we want to do with node
6675 * groups, so roll our own. Now each node has its own list of groups which
6676 * gets dynamically allocated.
6678 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
6679 static struct sched_group
***sched_group_nodes_bycpu
;
6681 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
6682 static DEFINE_PER_CPU(struct sched_group
, sched_group_allnodes
);
6684 static int cpu_to_allnodes_group(int cpu
, const cpumask_t
*cpu_map
,
6685 struct sched_group
**sg
, cpumask_t
*nodemask
)
6689 *nodemask
= node_to_cpumask(cpu_to_node(cpu
));
6690 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6691 group
= first_cpu(*nodemask
);
6694 *sg
= &per_cpu(sched_group_allnodes
, group
);
6698 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
6700 struct sched_group
*sg
= group_head
;
6706 for_each_cpu_mask(j
, sg
->cpumask
) {
6707 struct sched_domain
*sd
;
6709 sd
= &per_cpu(phys_domains
, j
);
6710 if (j
!= first_cpu(sd
->groups
->cpumask
)) {
6712 * Only add "power" once for each
6718 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
6721 } while (sg
!= group_head
);
6726 /* Free memory allocated for various sched_group structures */
6727 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6731 for_each_cpu_mask(cpu
, *cpu_map
) {
6732 struct sched_group
**sched_group_nodes
6733 = sched_group_nodes_bycpu
[cpu
];
6735 if (!sched_group_nodes
)
6738 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
6739 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
6741 *nodemask
= node_to_cpumask(i
);
6742 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6743 if (cpus_empty(*nodemask
))
6753 if (oldsg
!= sched_group_nodes
[i
])
6756 kfree(sched_group_nodes
);
6757 sched_group_nodes_bycpu
[cpu
] = NULL
;
6761 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
6767 * Initialize sched groups cpu_power.
6769 * cpu_power indicates the capacity of sched group, which is used while
6770 * distributing the load between different sched groups in a sched domain.
6771 * Typically cpu_power for all the groups in a sched domain will be same unless
6772 * there are asymmetries in the topology. If there are asymmetries, group
6773 * having more cpu_power will pickup more load compared to the group having
6776 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6777 * the maximum number of tasks a group can handle in the presence of other idle
6778 * or lightly loaded groups in the same sched domain.
6780 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
6782 struct sched_domain
*child
;
6783 struct sched_group
*group
;
6785 WARN_ON(!sd
|| !sd
->groups
);
6787 if (cpu
!= first_cpu(sd
->groups
->cpumask
))
6792 sd
->groups
->__cpu_power
= 0;
6795 * For perf policy, if the groups in child domain share resources
6796 * (for example cores sharing some portions of the cache hierarchy
6797 * or SMT), then set this domain groups cpu_power such that each group
6798 * can handle only one task, when there are other idle groups in the
6799 * same sched domain.
6801 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
6803 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
6804 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
6809 * add cpu_power of each child group to this groups cpu_power
6811 group
= child
->groups
;
6813 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
6814 group
= group
->next
;
6815 } while (group
!= child
->groups
);
6819 * Initializers for schedule domains
6820 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6823 #define SD_INIT(sd, type) sd_init_##type(sd)
6824 #define SD_INIT_FUNC(type) \
6825 static noinline void sd_init_##type(struct sched_domain *sd) \
6827 memset(sd, 0, sizeof(*sd)); \
6828 *sd = SD_##type##_INIT; \
6829 sd->level = SD_LV_##type; \
6834 SD_INIT_FUNC(ALLNODES
)
6837 #ifdef CONFIG_SCHED_SMT
6838 SD_INIT_FUNC(SIBLING
)
6840 #ifdef CONFIG_SCHED_MC
6845 * To minimize stack usage kmalloc room for cpumasks and share the
6846 * space as the usage in build_sched_domains() dictates. Used only
6847 * if the amount of space is significant.
6850 cpumask_t tmpmask
; /* make this one first */
6853 cpumask_t this_sibling_map
;
6854 cpumask_t this_core_map
;
6856 cpumask_t send_covered
;
6859 cpumask_t domainspan
;
6861 cpumask_t notcovered
;
6866 #define SCHED_CPUMASK_ALLOC 1
6867 #define SCHED_CPUMASK_FREE(v) kfree(v)
6868 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
6870 #define SCHED_CPUMASK_ALLOC 0
6871 #define SCHED_CPUMASK_FREE(v)
6872 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
6875 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
6876 ((unsigned long)(a) + offsetof(struct allmasks, v))
6878 static int default_relax_domain_level
= -1;
6880 static int __init
setup_relax_domain_level(char *str
)
6884 val
= simple_strtoul(str
, NULL
, 0);
6885 if (val
< SD_LV_MAX
)
6886 default_relax_domain_level
= val
;
6890 __setup("relax_domain_level=", setup_relax_domain_level
);
6892 static void set_domain_attribute(struct sched_domain
*sd
,
6893 struct sched_domain_attr
*attr
)
6897 if (!attr
|| attr
->relax_domain_level
< 0) {
6898 if (default_relax_domain_level
< 0)
6901 request
= default_relax_domain_level
;
6903 request
= attr
->relax_domain_level
;
6904 if (request
< sd
->level
) {
6905 /* turn off idle balance on this domain */
6906 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
6908 /* turn on idle balance on this domain */
6909 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
6914 * Build sched domains for a given set of cpus and attach the sched domains
6915 * to the individual cpus
6917 static int __build_sched_domains(const cpumask_t
*cpu_map
,
6918 struct sched_domain_attr
*attr
)
6921 struct root_domain
*rd
;
6922 SCHED_CPUMASK_DECLARE(allmasks
);
6925 struct sched_group
**sched_group_nodes
= NULL
;
6926 int sd_allnodes
= 0;
6929 * Allocate the per-node list of sched groups
6931 sched_group_nodes
= kcalloc(MAX_NUMNODES
, sizeof(struct sched_group
*),
6933 if (!sched_group_nodes
) {
6934 printk(KERN_WARNING
"Can not alloc sched group node list\n");
6939 rd
= alloc_rootdomain();
6941 printk(KERN_WARNING
"Cannot alloc root domain\n");
6943 kfree(sched_group_nodes
);
6948 #if SCHED_CPUMASK_ALLOC
6949 /* get space for all scratch cpumask variables */
6950 allmasks
= kmalloc(sizeof(*allmasks
), GFP_KERNEL
);
6952 printk(KERN_WARNING
"Cannot alloc cpumask array\n");
6955 kfree(sched_group_nodes
);
6960 tmpmask
= (cpumask_t
*)allmasks
;
6964 sched_group_nodes_bycpu
[first_cpu(*cpu_map
)] = sched_group_nodes
;
6968 * Set up domains for cpus specified by the cpu_map.
6970 for_each_cpu_mask(i
, *cpu_map
) {
6971 struct sched_domain
*sd
= NULL
, *p
;
6972 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
6974 *nodemask
= node_to_cpumask(cpu_to_node(i
));
6975 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
6978 if (cpus_weight(*cpu_map
) >
6979 SD_NODES_PER_DOMAIN
*cpus_weight(*nodemask
)) {
6980 sd
= &per_cpu(allnodes_domains
, i
);
6981 SD_INIT(sd
, ALLNODES
);
6982 set_domain_attribute(sd
, attr
);
6983 sd
->span
= *cpu_map
;
6984 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
6990 sd
= &per_cpu(node_domains
, i
);
6992 set_domain_attribute(sd
, attr
);
6993 sched_domain_node_span(cpu_to_node(i
), &sd
->span
);
6997 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7001 sd
= &per_cpu(phys_domains
, i
);
7003 set_domain_attribute(sd
, attr
);
7004 sd
->span
= *nodemask
;
7008 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7010 #ifdef CONFIG_SCHED_MC
7012 sd
= &per_cpu(core_domains
, i
);
7014 set_domain_attribute(sd
, attr
);
7015 sd
->span
= cpu_coregroup_map(i
);
7016 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7019 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7022 #ifdef CONFIG_SCHED_SMT
7024 sd
= &per_cpu(cpu_domains
, i
);
7025 SD_INIT(sd
, SIBLING
);
7026 set_domain_attribute(sd
, attr
);
7027 sd
->span
= per_cpu(cpu_sibling_map
, i
);
7028 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7031 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7035 #ifdef CONFIG_SCHED_SMT
7036 /* Set up CPU (sibling) groups */
7037 for_each_cpu_mask(i
, *cpu_map
) {
7038 SCHED_CPUMASK_VAR(this_sibling_map
, allmasks
);
7039 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7041 *this_sibling_map
= per_cpu(cpu_sibling_map
, i
);
7042 cpus_and(*this_sibling_map
, *this_sibling_map
, *cpu_map
);
7043 if (i
!= first_cpu(*this_sibling_map
))
7046 init_sched_build_groups(this_sibling_map
, cpu_map
,
7048 send_covered
, tmpmask
);
7052 #ifdef CONFIG_SCHED_MC
7053 /* Set up multi-core groups */
7054 for_each_cpu_mask(i
, *cpu_map
) {
7055 SCHED_CPUMASK_VAR(this_core_map
, allmasks
);
7056 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7058 *this_core_map
= cpu_coregroup_map(i
);
7059 cpus_and(*this_core_map
, *this_core_map
, *cpu_map
);
7060 if (i
!= first_cpu(*this_core_map
))
7063 init_sched_build_groups(this_core_map
, cpu_map
,
7065 send_covered
, tmpmask
);
7069 /* Set up physical groups */
7070 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7071 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7072 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7074 *nodemask
= node_to_cpumask(i
);
7075 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7076 if (cpus_empty(*nodemask
))
7079 init_sched_build_groups(nodemask
, cpu_map
,
7081 send_covered
, tmpmask
);
7085 /* Set up node groups */
7087 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7089 init_sched_build_groups(cpu_map
, cpu_map
,
7090 &cpu_to_allnodes_group
,
7091 send_covered
, tmpmask
);
7094 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7095 /* Set up node groups */
7096 struct sched_group
*sg
, *prev
;
7097 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7098 SCHED_CPUMASK_VAR(domainspan
, allmasks
);
7099 SCHED_CPUMASK_VAR(covered
, allmasks
);
7102 *nodemask
= node_to_cpumask(i
);
7103 cpus_clear(*covered
);
7105 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7106 if (cpus_empty(*nodemask
)) {
7107 sched_group_nodes
[i
] = NULL
;
7111 sched_domain_node_span(i
, domainspan
);
7112 cpus_and(*domainspan
, *domainspan
, *cpu_map
);
7114 sg
= kmalloc_node(sizeof(struct sched_group
), GFP_KERNEL
, i
);
7116 printk(KERN_WARNING
"Can not alloc domain group for "
7120 sched_group_nodes
[i
] = sg
;
7121 for_each_cpu_mask(j
, *nodemask
) {
7122 struct sched_domain
*sd
;
7124 sd
= &per_cpu(node_domains
, j
);
7127 sg
->__cpu_power
= 0;
7128 sg
->cpumask
= *nodemask
;
7130 cpus_or(*covered
, *covered
, *nodemask
);
7133 for (j
= 0; j
< MAX_NUMNODES
; j
++) {
7134 SCHED_CPUMASK_VAR(notcovered
, allmasks
);
7135 int n
= (i
+ j
) % MAX_NUMNODES
;
7136 node_to_cpumask_ptr(pnodemask
, n
);
7138 cpus_complement(*notcovered
, *covered
);
7139 cpus_and(*tmpmask
, *notcovered
, *cpu_map
);
7140 cpus_and(*tmpmask
, *tmpmask
, *domainspan
);
7141 if (cpus_empty(*tmpmask
))
7144 cpus_and(*tmpmask
, *tmpmask
, *pnodemask
);
7145 if (cpus_empty(*tmpmask
))
7148 sg
= kmalloc_node(sizeof(struct sched_group
),
7152 "Can not alloc domain group for node %d\n", j
);
7155 sg
->__cpu_power
= 0;
7156 sg
->cpumask
= *tmpmask
;
7157 sg
->next
= prev
->next
;
7158 cpus_or(*covered
, *covered
, *tmpmask
);
7165 /* Calculate CPU power for physical packages and nodes */
7166 #ifdef CONFIG_SCHED_SMT
7167 for_each_cpu_mask(i
, *cpu_map
) {
7168 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
);
7170 init_sched_groups_power(i
, sd
);
7173 #ifdef CONFIG_SCHED_MC
7174 for_each_cpu_mask(i
, *cpu_map
) {
7175 struct sched_domain
*sd
= &per_cpu(core_domains
, i
);
7177 init_sched_groups_power(i
, sd
);
7181 for_each_cpu_mask(i
, *cpu_map
) {
7182 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
);
7184 init_sched_groups_power(i
, sd
);
7188 for (i
= 0; i
< MAX_NUMNODES
; i
++)
7189 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7192 struct sched_group
*sg
;
7194 cpu_to_allnodes_group(first_cpu(*cpu_map
), cpu_map
, &sg
,
7196 init_numa_sched_groups_power(sg
);
7200 /* Attach the domains */
7201 for_each_cpu_mask(i
, *cpu_map
) {
7202 struct sched_domain
*sd
;
7203 #ifdef CONFIG_SCHED_SMT
7204 sd
= &per_cpu(cpu_domains
, i
);
7205 #elif defined(CONFIG_SCHED_MC)
7206 sd
= &per_cpu(core_domains
, i
);
7208 sd
= &per_cpu(phys_domains
, i
);
7210 cpu_attach_domain(sd
, rd
, i
);
7213 SCHED_CPUMASK_FREE((void *)allmasks
);
7218 free_sched_groups(cpu_map
, tmpmask
);
7219 SCHED_CPUMASK_FREE((void *)allmasks
);
7224 static int build_sched_domains(const cpumask_t
*cpu_map
)
7226 return __build_sched_domains(cpu_map
, NULL
);
7229 static cpumask_t
*doms_cur
; /* current sched domains */
7230 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7231 static struct sched_domain_attr
*dattr_cur
;
7232 /* attribues of custom domains in 'doms_cur' */
7235 * Special case: If a kmalloc of a doms_cur partition (array of
7236 * cpumask_t) fails, then fallback to a single sched domain,
7237 * as determined by the single cpumask_t fallback_doms.
7239 static cpumask_t fallback_doms
;
7241 void __attribute__((weak
)) arch_update_cpu_topology(void)
7246 * Free current domain masks.
7247 * Called after all cpus are attached to NULL domain.
7249 static void free_sched_domains(void)
7252 if (doms_cur
!= &fallback_doms
)
7254 doms_cur
= &fallback_doms
;
7258 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7259 * For now this just excludes isolated cpus, but could be used to
7260 * exclude other special cases in the future.
7262 static int arch_init_sched_domains(const cpumask_t
*cpu_map
)
7266 arch_update_cpu_topology();
7268 doms_cur
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
7270 doms_cur
= &fallback_doms
;
7271 cpus_andnot(*doms_cur
, *cpu_map
, cpu_isolated_map
);
7273 err
= build_sched_domains(doms_cur
);
7274 register_sched_domain_sysctl();
7279 static void arch_destroy_sched_domains(const cpumask_t
*cpu_map
,
7282 free_sched_groups(cpu_map
, tmpmask
);
7286 * Detach sched domains from a group of cpus specified in cpu_map
7287 * These cpus will now be attached to the NULL domain
7289 static void detach_destroy_domains(const cpumask_t
*cpu_map
)
7294 unregister_sched_domain_sysctl();
7296 for_each_cpu_mask(i
, *cpu_map
)
7297 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7298 synchronize_sched();
7299 arch_destroy_sched_domains(cpu_map
, &tmpmask
);
7302 /* handle null as "default" */
7303 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7304 struct sched_domain_attr
*new, int idx_new
)
7306 struct sched_domain_attr tmp
;
7313 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7314 new ? (new + idx_new
) : &tmp
,
7315 sizeof(struct sched_domain_attr
));
7319 * Partition sched domains as specified by the 'ndoms_new'
7320 * cpumasks in the array doms_new[] of cpumasks. This compares
7321 * doms_new[] to the current sched domain partitioning, doms_cur[].
7322 * It destroys each deleted domain and builds each new domain.
7324 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7325 * The masks don't intersect (don't overlap.) We should setup one
7326 * sched domain for each mask. CPUs not in any of the cpumasks will
7327 * not be load balanced. If the same cpumask appears both in the
7328 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7331 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7332 * ownership of it and will kfree it when done with it. If the caller
7333 * failed the kmalloc call, then it can pass in doms_new == NULL,
7334 * and partition_sched_domains() will fallback to the single partition
7337 * Call with hotplug lock held
7339 void partition_sched_domains(int ndoms_new
, cpumask_t
*doms_new
,
7340 struct sched_domain_attr
*dattr_new
)
7344 mutex_lock(&sched_domains_mutex
);
7346 /* always unregister in case we don't destroy any domains */
7347 unregister_sched_domain_sysctl();
7349 if (doms_new
== NULL
) {
7351 doms_new
= &fallback_doms
;
7352 cpus_andnot(doms_new
[0], cpu_online_map
, cpu_isolated_map
);
7356 /* Destroy deleted domains */
7357 for (i
= 0; i
< ndoms_cur
; i
++) {
7358 for (j
= 0; j
< ndoms_new
; j
++) {
7359 if (cpus_equal(doms_cur
[i
], doms_new
[j
])
7360 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7363 /* no match - a current sched domain not in new doms_new[] */
7364 detach_destroy_domains(doms_cur
+ i
);
7369 /* Build new domains */
7370 for (i
= 0; i
< ndoms_new
; i
++) {
7371 for (j
= 0; j
< ndoms_cur
; j
++) {
7372 if (cpus_equal(doms_new
[i
], doms_cur
[j
])
7373 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7376 /* no match - add a new doms_new */
7377 __build_sched_domains(doms_new
+ i
,
7378 dattr_new
? dattr_new
+ i
: NULL
);
7383 /* Remember the new sched domains */
7384 if (doms_cur
!= &fallback_doms
)
7386 kfree(dattr_cur
); /* kfree(NULL) is safe */
7387 doms_cur
= doms_new
;
7388 dattr_cur
= dattr_new
;
7389 ndoms_cur
= ndoms_new
;
7391 register_sched_domain_sysctl();
7393 mutex_unlock(&sched_domains_mutex
);
7396 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7397 int arch_reinit_sched_domains(void)
7402 mutex_lock(&sched_domains_mutex
);
7403 detach_destroy_domains(&cpu_online_map
);
7404 free_sched_domains();
7405 err
= arch_init_sched_domains(&cpu_online_map
);
7406 mutex_unlock(&sched_domains_mutex
);
7412 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7416 if (buf
[0] != '0' && buf
[0] != '1')
7420 sched_smt_power_savings
= (buf
[0] == '1');
7422 sched_mc_power_savings
= (buf
[0] == '1');
7424 ret
= arch_reinit_sched_domains();
7426 return ret
? ret
: count
;
7429 #ifdef CONFIG_SCHED_MC
7430 static ssize_t
sched_mc_power_savings_show(struct sys_device
*dev
, char *page
)
7432 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7434 static ssize_t
sched_mc_power_savings_store(struct sys_device
*dev
,
7435 const char *buf
, size_t count
)
7437 return sched_power_savings_store(buf
, count
, 0);
7439 static SYSDEV_ATTR(sched_mc_power_savings
, 0644, sched_mc_power_savings_show
,
7440 sched_mc_power_savings_store
);
7443 #ifdef CONFIG_SCHED_SMT
7444 static ssize_t
sched_smt_power_savings_show(struct sys_device
*dev
, char *page
)
7446 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7448 static ssize_t
sched_smt_power_savings_store(struct sys_device
*dev
,
7449 const char *buf
, size_t count
)
7451 return sched_power_savings_store(buf
, count
, 1);
7453 static SYSDEV_ATTR(sched_smt_power_savings
, 0644, sched_smt_power_savings_show
,
7454 sched_smt_power_savings_store
);
7457 int sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7461 #ifdef CONFIG_SCHED_SMT
7463 err
= sysfs_create_file(&cls
->kset
.kobj
,
7464 &attr_sched_smt_power_savings
.attr
);
7466 #ifdef CONFIG_SCHED_MC
7467 if (!err
&& mc_capable())
7468 err
= sysfs_create_file(&cls
->kset
.kobj
,
7469 &attr_sched_mc_power_savings
.attr
);
7476 * Force a reinitialization of the sched domains hierarchy. The domains
7477 * and groups cannot be updated in place without racing with the balancing
7478 * code, so we temporarily attach all running cpus to the NULL domain
7479 * which will prevent rebalancing while the sched domains are recalculated.
7481 static int update_sched_domains(struct notifier_block
*nfb
,
7482 unsigned long action
, void *hcpu
)
7485 case CPU_UP_PREPARE
:
7486 case CPU_UP_PREPARE_FROZEN
:
7487 case CPU_DOWN_PREPARE
:
7488 case CPU_DOWN_PREPARE_FROZEN
:
7489 detach_destroy_domains(&cpu_online_map
);
7490 free_sched_domains();
7493 case CPU_UP_CANCELED
:
7494 case CPU_UP_CANCELED_FROZEN
:
7495 case CPU_DOWN_FAILED
:
7496 case CPU_DOWN_FAILED_FROZEN
:
7498 case CPU_ONLINE_FROZEN
:
7500 case CPU_DEAD_FROZEN
:
7502 * Fall through and re-initialise the domains.
7509 #ifndef CONFIG_CPUSETS
7511 * Create default domain partitioning if cpusets are disabled.
7512 * Otherwise we let cpusets rebuild the domains based on the
7516 /* The hotplug lock is already held by cpu_up/cpu_down */
7517 arch_init_sched_domains(&cpu_online_map
);
7523 void __init
sched_init_smp(void)
7525 cpumask_t non_isolated_cpus
;
7527 #if defined(CONFIG_NUMA)
7528 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7530 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7533 mutex_lock(&sched_domains_mutex
);
7534 arch_init_sched_domains(&cpu_online_map
);
7535 cpus_andnot(non_isolated_cpus
, cpu_possible_map
, cpu_isolated_map
);
7536 if (cpus_empty(non_isolated_cpus
))
7537 cpu_set(smp_processor_id(), non_isolated_cpus
);
7538 mutex_unlock(&sched_domains_mutex
);
7540 /* XXX: Theoretical race here - CPU may be hotplugged now */
7541 hotcpu_notifier(update_sched_domains
, 0);
7544 /* Move init over to a non-isolated CPU */
7545 if (set_cpus_allowed_ptr(current
, &non_isolated_cpus
) < 0)
7547 sched_init_granularity();
7550 void __init
sched_init_smp(void)
7552 sched_init_granularity();
7554 #endif /* CONFIG_SMP */
7556 int in_sched_functions(unsigned long addr
)
7558 return in_lock_functions(addr
) ||
7559 (addr
>= (unsigned long)__sched_text_start
7560 && addr
< (unsigned long)__sched_text_end
);
7563 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
7565 cfs_rq
->tasks_timeline
= RB_ROOT
;
7566 INIT_LIST_HEAD(&cfs_rq
->tasks
);
7567 #ifdef CONFIG_FAIR_GROUP_SCHED
7570 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
7573 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
7575 struct rt_prio_array
*array
;
7578 array
= &rt_rq
->active
;
7579 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
7580 INIT_LIST_HEAD(array
->queue
+ i
);
7581 __clear_bit(i
, array
->bitmap
);
7583 /* delimiter for bitsearch: */
7584 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
7586 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
7587 rt_rq
->highest_prio
= MAX_RT_PRIO
;
7590 rt_rq
->rt_nr_migratory
= 0;
7591 rt_rq
->overloaded
= 0;
7595 rt_rq
->rt_throttled
= 0;
7596 rt_rq
->rt_runtime
= 0;
7597 spin_lock_init(&rt_rq
->rt_runtime_lock
);
7599 #ifdef CONFIG_RT_GROUP_SCHED
7600 rt_rq
->rt_nr_boosted
= 0;
7605 #ifdef CONFIG_FAIR_GROUP_SCHED
7606 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
7607 struct sched_entity
*se
, int cpu
, int add
,
7608 struct sched_entity
*parent
)
7610 struct rq
*rq
= cpu_rq(cpu
);
7611 tg
->cfs_rq
[cpu
] = cfs_rq
;
7612 init_cfs_rq(cfs_rq
, rq
);
7615 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
7618 /* se could be NULL for init_task_group */
7623 se
->cfs_rq
= &rq
->cfs
;
7625 se
->cfs_rq
= parent
->my_q
;
7628 se
->load
.weight
= tg
->shares
;
7629 se
->load
.inv_weight
= 0;
7630 se
->parent
= parent
;
7634 #ifdef CONFIG_RT_GROUP_SCHED
7635 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
7636 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
7637 struct sched_rt_entity
*parent
)
7639 struct rq
*rq
= cpu_rq(cpu
);
7641 tg
->rt_rq
[cpu
] = rt_rq
;
7642 init_rt_rq(rt_rq
, rq
);
7644 rt_rq
->rt_se
= rt_se
;
7645 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
7647 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
7649 tg
->rt_se
[cpu
] = rt_se
;
7654 rt_se
->rt_rq
= &rq
->rt
;
7656 rt_se
->rt_rq
= parent
->my_q
;
7658 rt_se
->my_q
= rt_rq
;
7659 rt_se
->parent
= parent
;
7660 INIT_LIST_HEAD(&rt_se
->run_list
);
7664 void __init
sched_init(void)
7667 unsigned long alloc_size
= 0, ptr
;
7669 #ifdef CONFIG_FAIR_GROUP_SCHED
7670 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7672 #ifdef CONFIG_RT_GROUP_SCHED
7673 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
7675 #ifdef CONFIG_USER_SCHED
7679 * As sched_init() is called before page_alloc is setup,
7680 * we use alloc_bootmem().
7683 ptr
= (unsigned long)alloc_bootmem(alloc_size
);
7685 #ifdef CONFIG_FAIR_GROUP_SCHED
7686 init_task_group
.se
= (struct sched_entity
**)ptr
;
7687 ptr
+= nr_cpu_ids
* sizeof(void **);
7689 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7690 ptr
+= nr_cpu_ids
* sizeof(void **);
7692 #ifdef CONFIG_USER_SCHED
7693 root_task_group
.se
= (struct sched_entity
**)ptr
;
7694 ptr
+= nr_cpu_ids
* sizeof(void **);
7696 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
7697 ptr
+= nr_cpu_ids
* sizeof(void **);
7700 #ifdef CONFIG_RT_GROUP_SCHED
7701 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7702 ptr
+= nr_cpu_ids
* sizeof(void **);
7704 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7705 ptr
+= nr_cpu_ids
* sizeof(void **);
7707 #ifdef CONFIG_USER_SCHED
7708 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
7709 ptr
+= nr_cpu_ids
* sizeof(void **);
7711 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
7712 ptr
+= nr_cpu_ids
* sizeof(void **);
7718 init_defrootdomain();
7721 init_rt_bandwidth(&def_rt_bandwidth
,
7722 global_rt_period(), global_rt_runtime());
7724 #ifdef CONFIG_RT_GROUP_SCHED
7725 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
7726 global_rt_period(), global_rt_runtime());
7727 #ifdef CONFIG_USER_SCHED
7728 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
7729 global_rt_period(), RUNTIME_INF
);
7733 #ifdef CONFIG_GROUP_SCHED
7734 list_add(&init_task_group
.list
, &task_groups
);
7735 INIT_LIST_HEAD(&init_task_group
.children
);
7737 #ifdef CONFIG_USER_SCHED
7738 INIT_LIST_HEAD(&root_task_group
.children
);
7739 init_task_group
.parent
= &root_task_group
;
7740 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
7744 for_each_possible_cpu(i
) {
7748 spin_lock_init(&rq
->lock
);
7749 lockdep_set_class(&rq
->lock
, &rq
->rq_lock_key
);
7751 init_cfs_rq(&rq
->cfs
, rq
);
7752 init_rt_rq(&rq
->rt
, rq
);
7753 #ifdef CONFIG_FAIR_GROUP_SCHED
7754 init_task_group
.shares
= init_task_group_load
;
7755 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
7756 #ifdef CONFIG_CGROUP_SCHED
7758 * How much cpu bandwidth does init_task_group get?
7760 * In case of task-groups formed thr' the cgroup filesystem, it
7761 * gets 100% of the cpu resources in the system. This overall
7762 * system cpu resource is divided among the tasks of
7763 * init_task_group and its child task-groups in a fair manner,
7764 * based on each entity's (task or task-group's) weight
7765 * (se->load.weight).
7767 * In other words, if init_task_group has 10 tasks of weight
7768 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7769 * then A0's share of the cpu resource is:
7771 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7773 * We achieve this by letting init_task_group's tasks sit
7774 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7776 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
7777 #elif defined CONFIG_USER_SCHED
7778 root_task_group
.shares
= NICE_0_LOAD
;
7779 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
7781 * In case of task-groups formed thr' the user id of tasks,
7782 * init_task_group represents tasks belonging to root user.
7783 * Hence it forms a sibling of all subsequent groups formed.
7784 * In this case, init_task_group gets only a fraction of overall
7785 * system cpu resource, based on the weight assigned to root
7786 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
7787 * by letting tasks of init_task_group sit in a separate cfs_rq
7788 * (init_cfs_rq) and having one entity represent this group of
7789 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
7791 init_tg_cfs_entry(&init_task_group
,
7792 &per_cpu(init_cfs_rq
, i
),
7793 &per_cpu(init_sched_entity
, i
), i
, 1,
7794 root_task_group
.se
[i
]);
7797 #endif /* CONFIG_FAIR_GROUP_SCHED */
7799 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
7800 #ifdef CONFIG_RT_GROUP_SCHED
7801 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
7802 #ifdef CONFIG_CGROUP_SCHED
7803 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
7804 #elif defined CONFIG_USER_SCHED
7805 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
7806 init_tg_rt_entry(&init_task_group
,
7807 &per_cpu(init_rt_rq
, i
),
7808 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
7809 root_task_group
.rt_se
[i
]);
7813 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
7814 rq
->cpu_load
[j
] = 0;
7818 rq
->active_balance
= 0;
7819 rq
->next_balance
= jiffies
;
7822 rq
->migration_thread
= NULL
;
7823 INIT_LIST_HEAD(&rq
->migration_queue
);
7824 rq_attach_root(rq
, &def_root_domain
);
7827 atomic_set(&rq
->nr_iowait
, 0);
7830 set_load_weight(&init_task
);
7832 #ifdef CONFIG_PREEMPT_NOTIFIERS
7833 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
7837 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
, NULL
);
7840 #ifdef CONFIG_RT_MUTEXES
7841 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
7845 * The boot idle thread does lazy MMU switching as well:
7847 atomic_inc(&init_mm
.mm_count
);
7848 enter_lazy_tlb(&init_mm
, current
);
7851 * Make us the idle thread. Technically, schedule() should not be
7852 * called from this thread, however somewhere below it might be,
7853 * but because we are the idle thread, we just pick up running again
7854 * when this runqueue becomes "idle".
7856 init_idle(current
, smp_processor_id());
7858 * During early bootup we pretend to be a normal task:
7860 current
->sched_class
= &fair_sched_class
;
7862 scheduler_running
= 1;
7865 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7866 void __might_sleep(char *file
, int line
)
7869 static unsigned long prev_jiffy
; /* ratelimiting */
7871 if ((in_atomic() || irqs_disabled()) &&
7872 system_state
== SYSTEM_RUNNING
&& !oops_in_progress
) {
7873 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
7875 prev_jiffy
= jiffies
;
7876 printk(KERN_ERR
"BUG: sleeping function called from invalid"
7877 " context at %s:%d\n", file
, line
);
7878 printk("in_atomic():%d, irqs_disabled():%d\n",
7879 in_atomic(), irqs_disabled());
7880 debug_show_held_locks(current
);
7881 if (irqs_disabled())
7882 print_irqtrace_events(current
);
7887 EXPORT_SYMBOL(__might_sleep
);
7890 #ifdef CONFIG_MAGIC_SYSRQ
7891 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
7895 update_rq_clock(rq
);
7896 on_rq
= p
->se
.on_rq
;
7898 deactivate_task(rq
, p
, 0);
7899 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
7901 activate_task(rq
, p
, 0);
7902 resched_task(rq
->curr
);
7906 void normalize_rt_tasks(void)
7908 struct task_struct
*g
, *p
;
7909 unsigned long flags
;
7912 read_lock_irqsave(&tasklist_lock
, flags
);
7913 do_each_thread(g
, p
) {
7915 * Only normalize user tasks:
7920 p
->se
.exec_start
= 0;
7921 #ifdef CONFIG_SCHEDSTATS
7922 p
->se
.wait_start
= 0;
7923 p
->se
.sleep_start
= 0;
7924 p
->se
.block_start
= 0;
7929 * Renice negative nice level userspace
7932 if (TASK_NICE(p
) < 0 && p
->mm
)
7933 set_user_nice(p
, 0);
7937 spin_lock(&p
->pi_lock
);
7938 rq
= __task_rq_lock(p
);
7940 normalize_task(rq
, p
);
7942 __task_rq_unlock(rq
);
7943 spin_unlock(&p
->pi_lock
);
7944 } while_each_thread(g
, p
);
7946 read_unlock_irqrestore(&tasklist_lock
, flags
);
7949 #endif /* CONFIG_MAGIC_SYSRQ */
7953 * These functions are only useful for the IA64 MCA handling.
7955 * They can only be called when the whole system has been
7956 * stopped - every CPU needs to be quiescent, and no scheduling
7957 * activity can take place. Using them for anything else would
7958 * be a serious bug, and as a result, they aren't even visible
7959 * under any other configuration.
7963 * curr_task - return the current task for a given cpu.
7964 * @cpu: the processor in question.
7966 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7968 struct task_struct
*curr_task(int cpu
)
7970 return cpu_curr(cpu
);
7974 * set_curr_task - set the current task for a given cpu.
7975 * @cpu: the processor in question.
7976 * @p: the task pointer to set.
7978 * Description: This function must only be used when non-maskable interrupts
7979 * are serviced on a separate stack. It allows the architecture to switch the
7980 * notion of the current task on a cpu in a non-blocking manner. This function
7981 * must be called with all CPU's synchronized, and interrupts disabled, the
7982 * and caller must save the original value of the current task (see
7983 * curr_task() above) and restore that value before reenabling interrupts and
7984 * re-starting the system.
7986 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
7988 void set_curr_task(int cpu
, struct task_struct
*p
)
7995 #ifdef CONFIG_FAIR_GROUP_SCHED
7996 static void free_fair_sched_group(struct task_group
*tg
)
8000 for_each_possible_cpu(i
) {
8002 kfree(tg
->cfs_rq
[i
]);
8012 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8014 struct cfs_rq
*cfs_rq
;
8015 struct sched_entity
*se
, *parent_se
;
8019 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8022 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8026 tg
->shares
= NICE_0_LOAD
;
8028 for_each_possible_cpu(i
) {
8031 cfs_rq
= kmalloc_node(sizeof(struct cfs_rq
),
8032 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8036 se
= kmalloc_node(sizeof(struct sched_entity
),
8037 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8041 parent_se
= parent
? parent
->se
[i
] : NULL
;
8042 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent_se
);
8051 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8053 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
8054 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
8057 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8059 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
8062 static inline void free_fair_sched_group(struct task_group
*tg
)
8067 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8072 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8076 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8081 #ifdef CONFIG_RT_GROUP_SCHED
8082 static void free_rt_sched_group(struct task_group
*tg
)
8086 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8088 for_each_possible_cpu(i
) {
8090 kfree(tg
->rt_rq
[i
]);
8092 kfree(tg
->rt_se
[i
]);
8100 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8102 struct rt_rq
*rt_rq
;
8103 struct sched_rt_entity
*rt_se
, *parent_se
;
8107 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8110 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8114 init_rt_bandwidth(&tg
->rt_bandwidth
,
8115 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8117 for_each_possible_cpu(i
) {
8120 rt_rq
= kmalloc_node(sizeof(struct rt_rq
),
8121 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8125 rt_se
= kmalloc_node(sizeof(struct sched_rt_entity
),
8126 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8130 parent_se
= parent
? parent
->rt_se
[i
] : NULL
;
8131 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent_se
);
8140 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8142 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
8143 &cpu_rq(cpu
)->leaf_rt_rq_list
);
8146 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8148 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
8151 static inline void free_rt_sched_group(struct task_group
*tg
)
8156 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8161 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8165 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8170 #ifdef CONFIG_GROUP_SCHED
8171 static void free_sched_group(struct task_group
*tg
)
8173 free_fair_sched_group(tg
);
8174 free_rt_sched_group(tg
);
8178 /* allocate runqueue etc for a new task group */
8179 struct task_group
*sched_create_group(struct task_group
*parent
)
8181 struct task_group
*tg
;
8182 unsigned long flags
;
8185 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8187 return ERR_PTR(-ENOMEM
);
8189 if (!alloc_fair_sched_group(tg
, parent
))
8192 if (!alloc_rt_sched_group(tg
, parent
))
8195 spin_lock_irqsave(&task_group_lock
, flags
);
8196 for_each_possible_cpu(i
) {
8197 register_fair_sched_group(tg
, i
);
8198 register_rt_sched_group(tg
, i
);
8200 list_add_rcu(&tg
->list
, &task_groups
);
8202 WARN_ON(!parent
); /* root should already exist */
8204 tg
->parent
= parent
;
8205 list_add_rcu(&tg
->siblings
, &parent
->children
);
8206 INIT_LIST_HEAD(&tg
->children
);
8207 spin_unlock_irqrestore(&task_group_lock
, flags
);
8212 free_sched_group(tg
);
8213 return ERR_PTR(-ENOMEM
);
8216 /* rcu callback to free various structures associated with a task group */
8217 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8219 /* now it should be safe to free those cfs_rqs */
8220 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8223 /* Destroy runqueue etc associated with a task group */
8224 void sched_destroy_group(struct task_group
*tg
)
8226 unsigned long flags
;
8229 spin_lock_irqsave(&task_group_lock
, flags
);
8230 for_each_possible_cpu(i
) {
8231 unregister_fair_sched_group(tg
, i
);
8232 unregister_rt_sched_group(tg
, i
);
8234 list_del_rcu(&tg
->list
);
8235 list_del_rcu(&tg
->siblings
);
8236 spin_unlock_irqrestore(&task_group_lock
, flags
);
8238 /* wait for possible concurrent references to cfs_rqs complete */
8239 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8242 /* change task's runqueue when it moves between groups.
8243 * The caller of this function should have put the task in its new group
8244 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8245 * reflect its new group.
8247 void sched_move_task(struct task_struct
*tsk
)
8250 unsigned long flags
;
8253 rq
= task_rq_lock(tsk
, &flags
);
8255 update_rq_clock(rq
);
8257 running
= task_current(rq
, tsk
);
8258 on_rq
= tsk
->se
.on_rq
;
8261 dequeue_task(rq
, tsk
, 0);
8262 if (unlikely(running
))
8263 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8265 set_task_rq(tsk
, task_cpu(tsk
));
8267 #ifdef CONFIG_FAIR_GROUP_SCHED
8268 if (tsk
->sched_class
->moved_group
)
8269 tsk
->sched_class
->moved_group(tsk
);
8272 if (unlikely(running
))
8273 tsk
->sched_class
->set_curr_task(rq
);
8275 enqueue_task(rq
, tsk
, 0);
8277 task_rq_unlock(rq
, &flags
);
8281 #ifdef CONFIG_FAIR_GROUP_SCHED
8282 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8284 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8285 struct rq
*rq
= cfs_rq
->rq
;
8288 spin_lock_irq(&rq
->lock
);
8292 dequeue_entity(cfs_rq
, se
, 0);
8294 se
->load
.weight
= shares
;
8295 se
->load
.inv_weight
= 0;
8298 enqueue_entity(cfs_rq
, se
, 0);
8300 spin_unlock_irq(&rq
->lock
);
8303 static DEFINE_MUTEX(shares_mutex
);
8305 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8308 unsigned long flags
;
8311 * We can't change the weight of the root cgroup.
8316 if (shares
< MIN_SHARES
)
8317 shares
= MIN_SHARES
;
8318 else if (shares
> MAX_SHARES
)
8319 shares
= MAX_SHARES
;
8321 mutex_lock(&shares_mutex
);
8322 if (tg
->shares
== shares
)
8325 spin_lock_irqsave(&task_group_lock
, flags
);
8326 for_each_possible_cpu(i
)
8327 unregister_fair_sched_group(tg
, i
);
8328 list_del_rcu(&tg
->siblings
);
8329 spin_unlock_irqrestore(&task_group_lock
, flags
);
8331 /* wait for any ongoing reference to this group to finish */
8332 synchronize_sched();
8335 * Now we are free to modify the group's share on each cpu
8336 * w/o tripping rebalance_share or load_balance_fair.
8338 tg
->shares
= shares
;
8339 for_each_possible_cpu(i
)
8340 set_se_shares(tg
->se
[i
], shares
);
8343 * Enable load balance activity on this group, by inserting it back on
8344 * each cpu's rq->leaf_cfs_rq_list.
8346 spin_lock_irqsave(&task_group_lock
, flags
);
8347 for_each_possible_cpu(i
)
8348 register_fair_sched_group(tg
, i
);
8349 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
8350 spin_unlock_irqrestore(&task_group_lock
, flags
);
8352 mutex_unlock(&shares_mutex
);
8356 unsigned long sched_group_shares(struct task_group
*tg
)
8362 #ifdef CONFIG_RT_GROUP_SCHED
8364 * Ensure that the real time constraints are schedulable.
8366 static DEFINE_MUTEX(rt_constraints_mutex
);
8368 static unsigned long to_ratio(u64 period
, u64 runtime
)
8370 if (runtime
== RUNTIME_INF
)
8373 return div64_u64(runtime
<< 16, period
);
8376 #ifdef CONFIG_CGROUP_SCHED
8377 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8379 struct task_group
*tgi
, *parent
= tg
? tg
->parent
: NULL
;
8380 unsigned long total
= 0;
8383 if (global_rt_period() < period
)
8386 return to_ratio(period
, runtime
) <
8387 to_ratio(global_rt_period(), global_rt_runtime());
8390 if (ktime_to_ns(parent
->rt_bandwidth
.rt_period
) < period
)
8394 list_for_each_entry_rcu(tgi
, &parent
->children
, siblings
) {
8398 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8399 tgi
->rt_bandwidth
.rt_runtime
);
8403 return total
+ to_ratio(period
, runtime
) <
8404 to_ratio(ktime_to_ns(parent
->rt_bandwidth
.rt_period
),
8405 parent
->rt_bandwidth
.rt_runtime
);
8407 #elif defined CONFIG_USER_SCHED
8408 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8410 struct task_group
*tgi
;
8411 unsigned long total
= 0;
8412 unsigned long global_ratio
=
8413 to_ratio(global_rt_period(), global_rt_runtime());
8416 list_for_each_entry_rcu(tgi
, &task_groups
, list
) {
8420 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8421 tgi
->rt_bandwidth
.rt_runtime
);
8425 return total
+ to_ratio(period
, runtime
) < global_ratio
;
8429 /* Must be called with tasklist_lock held */
8430 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8432 struct task_struct
*g
, *p
;
8433 do_each_thread(g
, p
) {
8434 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8436 } while_each_thread(g
, p
);
8440 static int tg_set_bandwidth(struct task_group
*tg
,
8441 u64 rt_period
, u64 rt_runtime
)
8445 mutex_lock(&rt_constraints_mutex
);
8446 read_lock(&tasklist_lock
);
8447 if (rt_runtime
== 0 && tg_has_rt_tasks(tg
)) {
8451 if (!__rt_schedulable(tg
, rt_period
, rt_runtime
)) {
8456 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8457 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8458 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8460 for_each_possible_cpu(i
) {
8461 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8463 spin_lock(&rt_rq
->rt_runtime_lock
);
8464 rt_rq
->rt_runtime
= rt_runtime
;
8465 spin_unlock(&rt_rq
->rt_runtime_lock
);
8467 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8469 read_unlock(&tasklist_lock
);
8470 mutex_unlock(&rt_constraints_mutex
);
8475 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8477 u64 rt_runtime
, rt_period
;
8479 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8480 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8481 if (rt_runtime_us
< 0)
8482 rt_runtime
= RUNTIME_INF
;
8484 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8487 long sched_group_rt_runtime(struct task_group
*tg
)
8491 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8494 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8495 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8496 return rt_runtime_us
;
8499 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8501 u64 rt_runtime
, rt_period
;
8503 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8504 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8509 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8512 long sched_group_rt_period(struct task_group
*tg
)
8516 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8517 do_div(rt_period_us
, NSEC_PER_USEC
);
8518 return rt_period_us
;
8521 static int sched_rt_global_constraints(void)
8525 mutex_lock(&rt_constraints_mutex
);
8526 if (!__rt_schedulable(NULL
, 1, 0))
8528 mutex_unlock(&rt_constraints_mutex
);
8533 static int sched_rt_global_constraints(void)
8535 unsigned long flags
;
8538 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8539 for_each_possible_cpu(i
) {
8540 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
8542 spin_lock(&rt_rq
->rt_runtime_lock
);
8543 rt_rq
->rt_runtime
= global_rt_runtime();
8544 spin_unlock(&rt_rq
->rt_runtime_lock
);
8546 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
8552 int sched_rt_handler(struct ctl_table
*table
, int write
,
8553 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
8557 int old_period
, old_runtime
;
8558 static DEFINE_MUTEX(mutex
);
8561 old_period
= sysctl_sched_rt_period
;
8562 old_runtime
= sysctl_sched_rt_runtime
;
8564 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
8566 if (!ret
&& write
) {
8567 ret
= sched_rt_global_constraints();
8569 sysctl_sched_rt_period
= old_period
;
8570 sysctl_sched_rt_runtime
= old_runtime
;
8572 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
8573 def_rt_bandwidth
.rt_period
=
8574 ns_to_ktime(global_rt_period());
8577 mutex_unlock(&mutex
);
8582 #ifdef CONFIG_CGROUP_SCHED
8584 /* return corresponding task_group object of a cgroup */
8585 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
8587 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
8588 struct task_group
, css
);
8591 static struct cgroup_subsys_state
*
8592 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8594 struct task_group
*tg
, *parent
;
8596 if (!cgrp
->parent
) {
8597 /* This is early initialization for the top cgroup */
8598 init_task_group
.css
.cgroup
= cgrp
;
8599 return &init_task_group
.css
;
8602 parent
= cgroup_tg(cgrp
->parent
);
8603 tg
= sched_create_group(parent
);
8605 return ERR_PTR(-ENOMEM
);
8607 /* Bind the cgroup to task_group object we just created */
8608 tg
->css
.cgroup
= cgrp
;
8614 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8616 struct task_group
*tg
= cgroup_tg(cgrp
);
8618 sched_destroy_group(tg
);
8622 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8623 struct task_struct
*tsk
)
8625 #ifdef CONFIG_RT_GROUP_SCHED
8626 /* Don't accept realtime tasks when there is no way for them to run */
8627 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
8630 /* We don't support RT-tasks being in separate groups */
8631 if (tsk
->sched_class
!= &fair_sched_class
)
8639 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
8640 struct cgroup
*old_cont
, struct task_struct
*tsk
)
8642 sched_move_task(tsk
);
8645 #ifdef CONFIG_FAIR_GROUP_SCHED
8646 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
8649 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
8652 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
8654 struct task_group
*tg
= cgroup_tg(cgrp
);
8656 return (u64
) tg
->shares
;
8660 #ifdef CONFIG_RT_GROUP_SCHED
8661 static int cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
8664 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
8667 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8669 return sched_group_rt_runtime(cgroup_tg(cgrp
));
8672 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
8675 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
8678 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
8680 return sched_group_rt_period(cgroup_tg(cgrp
));
8684 static struct cftype cpu_files
[] = {
8685 #ifdef CONFIG_FAIR_GROUP_SCHED
8688 .read_u64
= cpu_shares_read_u64
,
8689 .write_u64
= cpu_shares_write_u64
,
8692 #ifdef CONFIG_RT_GROUP_SCHED
8694 .name
= "rt_runtime_us",
8695 .read_s64
= cpu_rt_runtime_read
,
8696 .write_s64
= cpu_rt_runtime_write
,
8699 .name
= "rt_period_us",
8700 .read_u64
= cpu_rt_period_read_uint
,
8701 .write_u64
= cpu_rt_period_write_uint
,
8706 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
8708 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
8711 struct cgroup_subsys cpu_cgroup_subsys
= {
8713 .create
= cpu_cgroup_create
,
8714 .destroy
= cpu_cgroup_destroy
,
8715 .can_attach
= cpu_cgroup_can_attach
,
8716 .attach
= cpu_cgroup_attach
,
8717 .populate
= cpu_cgroup_populate
,
8718 .subsys_id
= cpu_cgroup_subsys_id
,
8722 #endif /* CONFIG_CGROUP_SCHED */
8724 #ifdef CONFIG_CGROUP_CPUACCT
8727 * CPU accounting code for task groups.
8729 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8730 * (balbir@in.ibm.com).
8733 /* track cpu usage of a group of tasks */
8735 struct cgroup_subsys_state css
;
8736 /* cpuusage holds pointer to a u64-type object on every cpu */
8740 struct cgroup_subsys cpuacct_subsys
;
8742 /* return cpu accounting group corresponding to this container */
8743 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
8745 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
8746 struct cpuacct
, css
);
8749 /* return cpu accounting group to which this task belongs */
8750 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
8752 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
8753 struct cpuacct
, css
);
8756 /* create a new cpu accounting group */
8757 static struct cgroup_subsys_state
*cpuacct_create(
8758 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8760 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
8763 return ERR_PTR(-ENOMEM
);
8765 ca
->cpuusage
= alloc_percpu(u64
);
8766 if (!ca
->cpuusage
) {
8768 return ERR_PTR(-ENOMEM
);
8774 /* destroy an existing cpu accounting group */
8776 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8778 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8780 free_percpu(ca
->cpuusage
);
8784 /* return total cpu usage (in nanoseconds) of a group */
8785 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
8787 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8788 u64 totalcpuusage
= 0;
8791 for_each_possible_cpu(i
) {
8792 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8795 * Take rq->lock to make 64-bit addition safe on 32-bit
8798 spin_lock_irq(&cpu_rq(i
)->lock
);
8799 totalcpuusage
+= *cpuusage
;
8800 spin_unlock_irq(&cpu_rq(i
)->lock
);
8803 return totalcpuusage
;
8806 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
8809 struct cpuacct
*ca
= cgroup_ca(cgrp
);
8818 for_each_possible_cpu(i
) {
8819 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
8821 spin_lock_irq(&cpu_rq(i
)->lock
);
8823 spin_unlock_irq(&cpu_rq(i
)->lock
);
8829 static struct cftype files
[] = {
8832 .read_u64
= cpuusage_read
,
8833 .write_u64
= cpuusage_write
,
8837 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
8839 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
8843 * charge this task's execution time to its accounting group.
8845 * called with rq->lock held.
8847 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
8851 if (!cpuacct_subsys
.active
)
8856 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, task_cpu(tsk
));
8858 *cpuusage
+= cputime
;
8862 struct cgroup_subsys cpuacct_subsys
= {
8864 .create
= cpuacct_create
,
8865 .destroy
= cpuacct_destroy
,
8866 .populate
= cpuacct_populate
,
8867 .subsys_id
= cpuacct_subsys_id
,
8869 #endif /* CONFIG_CGROUP_CPUACCT */