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 * Scheduler clock - returns current time in nanosec units.
79 * This is default implementation.
80 * Architectures and sub-architectures can override this.
82 unsigned long long __attribute__((weak
)) sched_clock(void)
84 return (unsigned long long)jiffies
* (NSEC_PER_SEC
/ HZ
);
88 * Convert user-nice values [ -20 ... 0 ... 19 ]
89 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
92 #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
93 #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
94 #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
97 * 'User priority' is the nice value converted to something we
98 * can work with better when scaling various scheduler parameters,
99 * it's a [ 0 ... 39 ] range.
101 #define USER_PRIO(p) ((p)-MAX_RT_PRIO)
102 #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
103 #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
106 * Helpers for converting nanosecond timing to jiffy resolution
108 #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
110 #define NICE_0_LOAD SCHED_LOAD_SCALE
111 #define NICE_0_SHIFT SCHED_LOAD_SHIFT
114 * These are the 'tuning knobs' of the scheduler:
116 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
117 * Timeslices get refilled after they expire.
119 #define DEF_TIMESLICE (100 * HZ / 1000)
122 * single value that denotes runtime == period, ie unlimited time.
124 #define RUNTIME_INF ((u64)~0ULL)
128 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
129 * Since cpu_power is a 'constant', we can use a reciprocal divide.
131 static inline u32
sg_div_cpu_power(const struct sched_group
*sg
, u32 load
)
133 return reciprocal_divide(load
, sg
->reciprocal_cpu_power
);
137 * Each time a sched group cpu_power is changed,
138 * we must compute its reciprocal value
140 static inline void sg_inc_cpu_power(struct sched_group
*sg
, u32 val
)
142 sg
->__cpu_power
+= val
;
143 sg
->reciprocal_cpu_power
= reciprocal_value(sg
->__cpu_power
);
147 static inline int rt_policy(int policy
)
149 if (unlikely(policy
== SCHED_FIFO
) || unlikely(policy
== SCHED_RR
))
154 static inline int task_has_rt_policy(struct task_struct
*p
)
156 return rt_policy(p
->policy
);
160 * This is the priority-queue data structure of the RT scheduling class:
162 struct rt_prio_array
{
163 DECLARE_BITMAP(bitmap
, MAX_RT_PRIO
+1); /* include 1 bit for delimiter */
164 struct list_head queue
[MAX_RT_PRIO
];
167 struct rt_bandwidth
{
168 /* nests inside the rq lock: */
169 spinlock_t rt_runtime_lock
;
172 struct hrtimer rt_period_timer
;
175 static struct rt_bandwidth def_rt_bandwidth
;
177 static int do_sched_rt_period_timer(struct rt_bandwidth
*rt_b
, int overrun
);
179 static enum hrtimer_restart
sched_rt_period_timer(struct hrtimer
*timer
)
181 struct rt_bandwidth
*rt_b
=
182 container_of(timer
, struct rt_bandwidth
, rt_period_timer
);
188 now
= hrtimer_cb_get_time(timer
);
189 overrun
= hrtimer_forward(timer
, now
, rt_b
->rt_period
);
194 idle
= do_sched_rt_period_timer(rt_b
, overrun
);
197 return idle
? HRTIMER_NORESTART
: HRTIMER_RESTART
;
201 void init_rt_bandwidth(struct rt_bandwidth
*rt_b
, u64 period
, u64 runtime
)
203 rt_b
->rt_period
= ns_to_ktime(period
);
204 rt_b
->rt_runtime
= runtime
;
206 spin_lock_init(&rt_b
->rt_runtime_lock
);
208 hrtimer_init(&rt_b
->rt_period_timer
,
209 CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
210 rt_b
->rt_period_timer
.function
= sched_rt_period_timer
;
211 rt_b
->rt_period_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
214 static void start_rt_bandwidth(struct rt_bandwidth
*rt_b
)
218 if (rt_b
->rt_runtime
== RUNTIME_INF
)
221 if (hrtimer_active(&rt_b
->rt_period_timer
))
224 spin_lock(&rt_b
->rt_runtime_lock
);
226 if (hrtimer_active(&rt_b
->rt_period_timer
))
229 now
= hrtimer_cb_get_time(&rt_b
->rt_period_timer
);
230 hrtimer_forward(&rt_b
->rt_period_timer
, now
, rt_b
->rt_period
);
231 hrtimer_start(&rt_b
->rt_period_timer
,
232 rt_b
->rt_period_timer
.expires
,
235 spin_unlock(&rt_b
->rt_runtime_lock
);
238 #ifdef CONFIG_RT_GROUP_SCHED
239 static void destroy_rt_bandwidth(struct rt_bandwidth
*rt_b
)
241 hrtimer_cancel(&rt_b
->rt_period_timer
);
246 * sched_domains_mutex serializes calls to arch_init_sched_domains,
247 * detach_destroy_domains and partition_sched_domains.
249 static DEFINE_MUTEX(sched_domains_mutex
);
251 #ifdef CONFIG_GROUP_SCHED
253 #include <linux/cgroup.h>
257 static LIST_HEAD(task_groups
);
259 /* task group related information */
261 #ifdef CONFIG_CGROUP_SCHED
262 struct cgroup_subsys_state css
;
265 #ifdef CONFIG_FAIR_GROUP_SCHED
266 /* schedulable entities of this group on each cpu */
267 struct sched_entity
**se
;
268 /* runqueue "owned" by this group on each cpu */
269 struct cfs_rq
**cfs_rq
;
270 unsigned long shares
;
273 #ifdef CONFIG_RT_GROUP_SCHED
274 struct sched_rt_entity
**rt_se
;
275 struct rt_rq
**rt_rq
;
277 struct rt_bandwidth rt_bandwidth
;
281 struct list_head list
;
283 struct task_group
*parent
;
284 struct list_head siblings
;
285 struct list_head children
;
288 #ifdef CONFIG_USER_SCHED
292 * Every UID task group (including init_task_group aka UID-0) will
293 * be a child to this group.
295 struct task_group root_task_group
;
297 #ifdef CONFIG_FAIR_GROUP_SCHED
298 /* Default task group's sched entity on each cpu */
299 static DEFINE_PER_CPU(struct sched_entity
, init_sched_entity
);
300 /* Default task group's cfs_rq on each cpu */
301 static DEFINE_PER_CPU(struct cfs_rq
, init_cfs_rq
) ____cacheline_aligned_in_smp
;
304 #ifdef CONFIG_RT_GROUP_SCHED
305 static DEFINE_PER_CPU(struct sched_rt_entity
, init_sched_rt_entity
);
306 static DEFINE_PER_CPU(struct rt_rq
, init_rt_rq
) ____cacheline_aligned_in_smp
;
309 #define root_task_group init_task_group
312 /* task_group_lock serializes add/remove of task groups and also changes to
313 * a task group's cpu shares.
315 static DEFINE_SPINLOCK(task_group_lock
);
317 #ifdef CONFIG_FAIR_GROUP_SCHED
318 #ifdef CONFIG_USER_SCHED
319 # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
321 # define INIT_TASK_GROUP_LOAD NICE_0_LOAD
326 static int init_task_group_load
= INIT_TASK_GROUP_LOAD
;
329 /* Default task group.
330 * Every task in system belong to this group at bootup.
332 struct task_group init_task_group
;
334 /* return group to which a task belongs */
335 static inline struct task_group
*task_group(struct task_struct
*p
)
337 struct task_group
*tg
;
339 #ifdef CONFIG_USER_SCHED
341 #elif defined(CONFIG_CGROUP_SCHED)
342 tg
= container_of(task_subsys_state(p
, cpu_cgroup_subsys_id
),
343 struct task_group
, css
);
345 tg
= &init_task_group
;
350 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
351 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
)
353 #ifdef CONFIG_FAIR_GROUP_SCHED
354 p
->se
.cfs_rq
= task_group(p
)->cfs_rq
[cpu
];
355 p
->se
.parent
= task_group(p
)->se
[cpu
];
358 #ifdef CONFIG_RT_GROUP_SCHED
359 p
->rt
.rt_rq
= task_group(p
)->rt_rq
[cpu
];
360 p
->rt
.parent
= task_group(p
)->rt_se
[cpu
];
366 static inline void set_task_rq(struct task_struct
*p
, unsigned int cpu
) { }
368 #endif /* CONFIG_GROUP_SCHED */
370 /* CFS-related fields in a runqueue */
372 struct load_weight load
;
373 unsigned long nr_running
;
378 struct rb_root tasks_timeline
;
379 struct rb_node
*rb_leftmost
;
381 struct list_head tasks
;
382 struct list_head
*balance_iterator
;
385 * 'curr' points to currently running entity on this cfs_rq.
386 * It is set to NULL otherwise (i.e when none are currently running).
388 struct sched_entity
*curr
, *next
;
390 unsigned long nr_spread_over
;
392 #ifdef CONFIG_FAIR_GROUP_SCHED
393 struct rq
*rq
; /* cpu runqueue to which this cfs_rq is attached */
396 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
397 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
398 * (like users, containers etc.)
400 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
401 * list is used during load balance.
403 struct list_head leaf_cfs_rq_list
;
404 struct task_group
*tg
; /* group that "owns" this runqueue */
407 unsigned long task_weight
;
408 unsigned long shares
;
410 * We need space to build a sched_domain wide view of the full task
411 * group tree, in order to avoid depending on dynamic memory allocation
412 * during the load balancing we place this in the per cpu task group
413 * hierarchy. This limits the load balancing to one instance per cpu,
414 * but more should not be needed anyway.
416 struct aggregate_struct
{
418 * load = weight(cpus) * f(tg)
420 * Where f(tg) is the recursive weight fraction assigned to
426 * part of the group weight distributed to this span.
428 unsigned long shares
;
431 * The sum of all runqueue weights within this span.
433 unsigned long rq_weight
;
436 * Weight contributed by tasks; this is the part we can
437 * influence by moving tasks around.
439 unsigned long task_weight
;
445 /* Real-Time classes' related field in a runqueue: */
447 struct rt_prio_array active
;
448 unsigned long rt_nr_running
;
449 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
450 int highest_prio
; /* highest queued rt task prio */
453 unsigned long rt_nr_migratory
;
459 /* Nests inside the rq lock: */
460 spinlock_t rt_runtime_lock
;
462 #ifdef CONFIG_RT_GROUP_SCHED
463 unsigned long rt_nr_boosted
;
466 struct list_head leaf_rt_rq_list
;
467 struct task_group
*tg
;
468 struct sched_rt_entity
*rt_se
;
475 * We add the notion of a root-domain which will be used to define per-domain
476 * variables. Each exclusive cpuset essentially defines an island domain by
477 * fully partitioning the member cpus from any other cpuset. Whenever a new
478 * exclusive cpuset is created, we also create and attach a new root-domain
488 * The "RT overload" flag: it gets set if a CPU has more than
489 * one runnable RT task.
496 * By default the system creates a single root-domain with all cpus as
497 * members (mimicking the global state we have today).
499 static struct root_domain def_root_domain
;
504 * This is the main, per-CPU runqueue data structure.
506 * Locking rule: those places that want to lock multiple runqueues
507 * (such as the load balancing or the thread migration code), lock
508 * acquire operations must be ordered by ascending &runqueue.
515 * nr_running and cpu_load should be in the same cacheline because
516 * remote CPUs use both these fields when doing load calculation.
518 unsigned long nr_running
;
519 #define CPU_LOAD_IDX_MAX 5
520 unsigned long cpu_load
[CPU_LOAD_IDX_MAX
];
521 unsigned char idle_at_tick
;
523 unsigned long last_tick_seen
;
524 unsigned char in_nohz_recently
;
526 /* capture load from *all* tasks on this cpu: */
527 struct load_weight load
;
528 unsigned long nr_load_updates
;
534 #ifdef CONFIG_FAIR_GROUP_SCHED
535 /* list of leaf cfs_rq on this cpu: */
536 struct list_head leaf_cfs_rq_list
;
538 #ifdef CONFIG_RT_GROUP_SCHED
539 struct list_head leaf_rt_rq_list
;
543 * This is part of a global counter where only the total sum
544 * over all CPUs matters. A task can increase this counter on
545 * one CPU and if it got migrated afterwards it may decrease
546 * it on another CPU. Always updated under the runqueue lock:
548 unsigned long nr_uninterruptible
;
550 struct task_struct
*curr
, *idle
;
551 unsigned long next_balance
;
552 struct mm_struct
*prev_mm
;
554 u64 clock
, prev_clock_raw
;
557 unsigned int clock_warps
, clock_overflows
, clock_underflows
;
559 unsigned int clock_deep_idle_events
;
565 struct root_domain
*rd
;
566 struct sched_domain
*sd
;
568 /* For active balancing */
571 /* cpu of this runqueue: */
574 struct task_struct
*migration_thread
;
575 struct list_head migration_queue
;
578 #ifdef CONFIG_SCHED_HRTICK
579 unsigned long hrtick_flags
;
580 ktime_t hrtick_expire
;
581 struct hrtimer hrtick_timer
;
584 #ifdef CONFIG_SCHEDSTATS
586 struct sched_info rq_sched_info
;
588 /* sys_sched_yield() stats */
589 unsigned int yld_exp_empty
;
590 unsigned int yld_act_empty
;
591 unsigned int yld_both_empty
;
592 unsigned int yld_count
;
594 /* schedule() stats */
595 unsigned int sched_switch
;
596 unsigned int sched_count
;
597 unsigned int sched_goidle
;
599 /* try_to_wake_up() stats */
600 unsigned int ttwu_count
;
601 unsigned int ttwu_local
;
604 unsigned int bkl_count
;
606 struct lock_class_key rq_lock_key
;
609 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq
, runqueues
);
611 static inline void check_preempt_curr(struct rq
*rq
, struct task_struct
*p
)
613 rq
->curr
->sched_class
->check_preempt_curr(rq
, p
);
616 static inline int cpu_of(struct rq
*rq
)
626 static inline bool nohz_on(int cpu
)
628 return tick_get_tick_sched(cpu
)->nohz_mode
!= NOHZ_MODE_INACTIVE
;
631 static inline u64
max_skipped_ticks(struct rq
*rq
)
633 return nohz_on(cpu_of(rq
)) ? jiffies
- rq
->last_tick_seen
+ 2 : 1;
636 static inline void update_last_tick_seen(struct rq
*rq
)
638 rq
->last_tick_seen
= jiffies
;
641 static inline u64
max_skipped_ticks(struct rq
*rq
)
646 static inline void update_last_tick_seen(struct rq
*rq
)
652 * Update the per-runqueue clock, as finegrained as the platform can give
653 * us, but without assuming monotonicity, etc.:
655 static void __update_rq_clock(struct rq
*rq
)
657 u64 prev_raw
= rq
->prev_clock_raw
;
658 u64 now
= sched_clock();
659 s64 delta
= now
- prev_raw
;
660 u64 clock
= rq
->clock
;
662 #ifdef CONFIG_SCHED_DEBUG
663 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
666 * Protect against sched_clock() occasionally going backwards:
668 if (unlikely(delta
< 0)) {
673 * Catch too large forward jumps too:
675 u64 max_jump
= max_skipped_ticks(rq
) * TICK_NSEC
;
676 u64 max_time
= rq
->tick_timestamp
+ max_jump
;
678 if (unlikely(clock
+ delta
> max_time
)) {
679 if (clock
< max_time
)
683 rq
->clock_overflows
++;
685 if (unlikely(delta
> rq
->clock_max_delta
))
686 rq
->clock_max_delta
= delta
;
691 rq
->prev_clock_raw
= now
;
695 static void update_rq_clock(struct rq
*rq
)
697 if (likely(smp_processor_id() == cpu_of(rq
)))
698 __update_rq_clock(rq
);
702 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
703 * See detach_destroy_domains: synchronize_sched for details.
705 * The domain tree of any CPU may only be accessed from within
706 * preempt-disabled sections.
708 #define for_each_domain(cpu, __sd) \
709 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
711 #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
712 #define this_rq() (&__get_cpu_var(runqueues))
713 #define task_rq(p) cpu_rq(task_cpu(p))
714 #define cpu_curr(cpu) (cpu_rq(cpu)->curr)
717 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
719 #ifdef CONFIG_SCHED_DEBUG
720 # define const_debug __read_mostly
722 # define const_debug static const
726 * Debugging: various feature bits
729 #define SCHED_FEAT(name, enabled) \
730 __SCHED_FEAT_##name ,
733 #include "sched_features.h"
738 #define SCHED_FEAT(name, enabled) \
739 (1UL << __SCHED_FEAT_##name) * enabled |
741 const_debug
unsigned int sysctl_sched_features
=
742 #include "sched_features.h"
747 #ifdef CONFIG_SCHED_DEBUG
748 #define SCHED_FEAT(name, enabled) \
751 static __read_mostly
char *sched_feat_names
[] = {
752 #include "sched_features.h"
758 static int sched_feat_open(struct inode
*inode
, struct file
*filp
)
760 filp
->private_data
= inode
->i_private
;
765 sched_feat_read(struct file
*filp
, char __user
*ubuf
,
766 size_t cnt
, loff_t
*ppos
)
773 for (i
= 0; sched_feat_names
[i
]; i
++) {
774 len
+= strlen(sched_feat_names
[i
]);
778 buf
= kmalloc(len
+ 2, GFP_KERNEL
);
782 for (i
= 0; sched_feat_names
[i
]; i
++) {
783 if (sysctl_sched_features
& (1UL << i
))
784 r
+= sprintf(buf
+ r
, "%s ", sched_feat_names
[i
]);
786 r
+= sprintf(buf
+ r
, "NO_%s ", sched_feat_names
[i
]);
789 r
+= sprintf(buf
+ r
, "\n");
790 WARN_ON(r
>= len
+ 2);
792 r
= simple_read_from_buffer(ubuf
, cnt
, ppos
, buf
, r
);
800 sched_feat_write(struct file
*filp
, const char __user
*ubuf
,
801 size_t cnt
, loff_t
*ppos
)
811 if (copy_from_user(&buf
, ubuf
, cnt
))
816 if (strncmp(buf
, "NO_", 3) == 0) {
821 for (i
= 0; sched_feat_names
[i
]; i
++) {
822 int len
= strlen(sched_feat_names
[i
]);
824 if (strncmp(cmp
, sched_feat_names
[i
], len
) == 0) {
826 sysctl_sched_features
&= ~(1UL << i
);
828 sysctl_sched_features
|= (1UL << i
);
833 if (!sched_feat_names
[i
])
841 static struct file_operations sched_feat_fops
= {
842 .open
= sched_feat_open
,
843 .read
= sched_feat_read
,
844 .write
= sched_feat_write
,
847 static __init
int sched_init_debug(void)
849 debugfs_create_file("sched_features", 0644, NULL
, NULL
,
854 late_initcall(sched_init_debug
);
858 #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
861 * Number of tasks to iterate in a single balance run.
862 * Limited because this is done with IRQs disabled.
864 const_debug
unsigned int sysctl_sched_nr_migrate
= 32;
867 * period over which we measure -rt task cpu usage in us.
870 unsigned int sysctl_sched_rt_period
= 1000000;
872 static __read_mostly
int scheduler_running
;
875 * part of the period that we allow rt tasks to run in us.
878 int sysctl_sched_rt_runtime
= 950000;
880 static inline u64
global_rt_period(void)
882 return (u64
)sysctl_sched_rt_period
* NSEC_PER_USEC
;
885 static inline u64
global_rt_runtime(void)
887 if (sysctl_sched_rt_period
< 0)
890 return (u64
)sysctl_sched_rt_runtime
* NSEC_PER_USEC
;
893 unsigned long long time_sync_thresh
= 100000;
895 static DEFINE_PER_CPU(unsigned long long, time_offset
);
896 static DEFINE_PER_CPU(unsigned long long, prev_cpu_time
);
899 * Global lock which we take every now and then to synchronize
900 * the CPUs time. This method is not warp-safe, but it's good
901 * enough to synchronize slowly diverging time sources and thus
902 * it's good enough for tracing:
904 static DEFINE_SPINLOCK(time_sync_lock
);
905 static unsigned long long prev_global_time
;
907 static unsigned long long __sync_cpu_clock(cycles_t time
, int cpu
)
911 spin_lock_irqsave(&time_sync_lock
, flags
);
913 if (time
< prev_global_time
) {
914 per_cpu(time_offset
, cpu
) += prev_global_time
- time
;
915 time
= prev_global_time
;
917 prev_global_time
= time
;
920 spin_unlock_irqrestore(&time_sync_lock
, flags
);
925 static unsigned long long __cpu_clock(int cpu
)
927 unsigned long long now
;
932 * Only call sched_clock() if the scheduler has already been
933 * initialized (some code might call cpu_clock() very early):
935 if (unlikely(!scheduler_running
))
938 local_irq_save(flags
);
942 local_irq_restore(flags
);
948 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
949 * clock constructed from sched_clock():
951 unsigned long long cpu_clock(int cpu
)
953 unsigned long long prev_cpu_time
, time
, delta_time
;
955 prev_cpu_time
= per_cpu(prev_cpu_time
, cpu
);
956 time
= __cpu_clock(cpu
) + per_cpu(time_offset
, cpu
);
957 delta_time
= time
-prev_cpu_time
;
959 if (unlikely(delta_time
> time_sync_thresh
))
960 time
= __sync_cpu_clock(time
, cpu
);
964 EXPORT_SYMBOL_GPL(cpu_clock
);
966 #ifndef prepare_arch_switch
967 # define prepare_arch_switch(next) do { } while (0)
969 #ifndef finish_arch_switch
970 # define finish_arch_switch(prev) do { } while (0)
973 static inline int task_current(struct rq
*rq
, struct task_struct
*p
)
975 return rq
->curr
== p
;
978 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
979 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
981 return task_current(rq
, p
);
984 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
988 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
990 #ifdef CONFIG_DEBUG_SPINLOCK
991 /* this is a valid case when another task releases the spinlock */
992 rq
->lock
.owner
= current
;
995 * If we are tracking spinlock dependencies then we have to
996 * fix up the runqueue lock - which gets 'carried over' from
999 spin_acquire(&rq
->lock
.dep_map
, 0, 0, _THIS_IP_
);
1001 spin_unlock_irq(&rq
->lock
);
1004 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
1005 static inline int task_running(struct rq
*rq
, struct task_struct
*p
)
1010 return task_current(rq
, p
);
1014 static inline void prepare_lock_switch(struct rq
*rq
, struct task_struct
*next
)
1018 * We can optimise this out completely for !SMP, because the
1019 * SMP rebalancing from interrupt is the only thing that cares
1024 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1025 spin_unlock_irq(&rq
->lock
);
1027 spin_unlock(&rq
->lock
);
1031 static inline void finish_lock_switch(struct rq
*rq
, struct task_struct
*prev
)
1035 * After ->oncpu is cleared, the task can be moved to a different CPU.
1036 * We must ensure this doesn't happen until the switch is completely
1042 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
1046 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
1049 * __task_rq_lock - lock the runqueue a given task resides on.
1050 * Must be called interrupts disabled.
1052 static inline struct rq
*__task_rq_lock(struct task_struct
*p
)
1053 __acquires(rq
->lock
)
1056 struct rq
*rq
= task_rq(p
);
1057 spin_lock(&rq
->lock
);
1058 if (likely(rq
== task_rq(p
)))
1060 spin_unlock(&rq
->lock
);
1065 * task_rq_lock - lock the runqueue a given task resides on and disable
1066 * interrupts. Note the ordering: we can safely lookup the task_rq without
1067 * explicitly disabling preemption.
1069 static struct rq
*task_rq_lock(struct task_struct
*p
, unsigned long *flags
)
1070 __acquires(rq
->lock
)
1075 local_irq_save(*flags
);
1077 spin_lock(&rq
->lock
);
1078 if (likely(rq
== task_rq(p
)))
1080 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1084 static void __task_rq_unlock(struct rq
*rq
)
1085 __releases(rq
->lock
)
1087 spin_unlock(&rq
->lock
);
1090 static inline void task_rq_unlock(struct rq
*rq
, unsigned long *flags
)
1091 __releases(rq
->lock
)
1093 spin_unlock_irqrestore(&rq
->lock
, *flags
);
1097 * this_rq_lock - lock this runqueue and disable interrupts.
1099 static struct rq
*this_rq_lock(void)
1100 __acquires(rq
->lock
)
1104 local_irq_disable();
1106 spin_lock(&rq
->lock
);
1112 * We are going deep-idle (irqs are disabled):
1114 void sched_clock_idle_sleep_event(void)
1116 struct rq
*rq
= cpu_rq(smp_processor_id());
1118 WARN_ON(!irqs_disabled());
1119 spin_lock(&rq
->lock
);
1120 __update_rq_clock(rq
);
1121 spin_unlock(&rq
->lock
);
1122 rq
->clock_deep_idle_events
++;
1124 EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event
);
1127 * We just idled delta nanoseconds (called with irqs disabled):
1129 void sched_clock_idle_wakeup_event(u64 delta_ns
)
1131 struct rq
*rq
= cpu_rq(smp_processor_id());
1132 u64 now
= sched_clock();
1134 WARN_ON(!irqs_disabled());
1135 rq
->idle_clock
+= delta_ns
;
1137 * Override the previous timestamp and ignore all
1138 * sched_clock() deltas that occured while we idled,
1139 * and use the PM-provided delta_ns to advance the
1142 spin_lock(&rq
->lock
);
1143 rq
->prev_clock_raw
= now
;
1144 rq
->clock
+= delta_ns
;
1145 spin_unlock(&rq
->lock
);
1146 touch_softlockup_watchdog();
1148 EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event
);
1150 static void __resched_task(struct task_struct
*p
, int tif_bit
);
1152 static inline void resched_task(struct task_struct
*p
)
1154 __resched_task(p
, TIF_NEED_RESCHED
);
1157 #ifdef CONFIG_SCHED_HRTICK
1159 * Use HR-timers to deliver accurate preemption points.
1161 * Its all a bit involved since we cannot program an hrt while holding the
1162 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1165 * When we get rescheduled we reprogram the hrtick_timer outside of the
1168 static inline void resched_hrt(struct task_struct
*p
)
1170 __resched_task(p
, TIF_HRTICK_RESCHED
);
1173 static inline void resched_rq(struct rq
*rq
)
1175 unsigned long flags
;
1177 spin_lock_irqsave(&rq
->lock
, flags
);
1178 resched_task(rq
->curr
);
1179 spin_unlock_irqrestore(&rq
->lock
, flags
);
1183 HRTICK_SET
, /* re-programm hrtick_timer */
1184 HRTICK_RESET
, /* not a new slice */
1185 HRTICK_BLOCK
, /* stop hrtick operations */
1190 * - enabled by features
1191 * - hrtimer is actually high res
1193 static inline int hrtick_enabled(struct rq
*rq
)
1195 if (!sched_feat(HRTICK
))
1197 if (unlikely(test_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
)))
1199 return hrtimer_is_hres_active(&rq
->hrtick_timer
);
1203 * Called to set the hrtick timer state.
1205 * called with rq->lock held and irqs disabled
1207 static void hrtick_start(struct rq
*rq
, u64 delay
, int reset
)
1209 assert_spin_locked(&rq
->lock
);
1212 * preempt at: now + delay
1215 ktime_add_ns(rq
->hrtick_timer
.base
->get_time(), delay
);
1217 * indicate we need to program the timer
1219 __set_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1221 __set_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1224 * New slices are called from the schedule path and don't need a
1225 * forced reschedule.
1228 resched_hrt(rq
->curr
);
1231 static void hrtick_clear(struct rq
*rq
)
1233 if (hrtimer_active(&rq
->hrtick_timer
))
1234 hrtimer_cancel(&rq
->hrtick_timer
);
1238 * Update the timer from the possible pending state.
1240 static void hrtick_set(struct rq
*rq
)
1244 unsigned long flags
;
1246 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1248 spin_lock_irqsave(&rq
->lock
, flags
);
1249 set
= __test_and_clear_bit(HRTICK_SET
, &rq
->hrtick_flags
);
1250 reset
= __test_and_clear_bit(HRTICK_RESET
, &rq
->hrtick_flags
);
1251 time
= rq
->hrtick_expire
;
1252 clear_thread_flag(TIF_HRTICK_RESCHED
);
1253 spin_unlock_irqrestore(&rq
->lock
, flags
);
1256 hrtimer_start(&rq
->hrtick_timer
, time
, HRTIMER_MODE_ABS
);
1257 if (reset
&& !hrtimer_active(&rq
->hrtick_timer
))
1264 * High-resolution timer tick.
1265 * Runs from hardirq context with interrupts disabled.
1267 static enum hrtimer_restart
hrtick(struct hrtimer
*timer
)
1269 struct rq
*rq
= container_of(timer
, struct rq
, hrtick_timer
);
1271 WARN_ON_ONCE(cpu_of(rq
) != smp_processor_id());
1273 spin_lock(&rq
->lock
);
1274 __update_rq_clock(rq
);
1275 rq
->curr
->sched_class
->task_tick(rq
, rq
->curr
, 1);
1276 spin_unlock(&rq
->lock
);
1278 return HRTIMER_NORESTART
;
1281 static void hotplug_hrtick_disable(int cpu
)
1283 struct rq
*rq
= cpu_rq(cpu
);
1284 unsigned long flags
;
1286 spin_lock_irqsave(&rq
->lock
, flags
);
1287 rq
->hrtick_flags
= 0;
1288 __set_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
);
1289 spin_unlock_irqrestore(&rq
->lock
, flags
);
1294 static void hotplug_hrtick_enable(int cpu
)
1296 struct rq
*rq
= cpu_rq(cpu
);
1297 unsigned long flags
;
1299 spin_lock_irqsave(&rq
->lock
, flags
);
1300 __clear_bit(HRTICK_BLOCK
, &rq
->hrtick_flags
);
1301 spin_unlock_irqrestore(&rq
->lock
, flags
);
1305 hotplug_hrtick(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
1307 int cpu
= (int)(long)hcpu
;
1310 case CPU_UP_CANCELED
:
1311 case CPU_UP_CANCELED_FROZEN
:
1312 case CPU_DOWN_PREPARE
:
1313 case CPU_DOWN_PREPARE_FROZEN
:
1315 case CPU_DEAD_FROZEN
:
1316 hotplug_hrtick_disable(cpu
);
1319 case CPU_UP_PREPARE
:
1320 case CPU_UP_PREPARE_FROZEN
:
1321 case CPU_DOWN_FAILED
:
1322 case CPU_DOWN_FAILED_FROZEN
:
1324 case CPU_ONLINE_FROZEN
:
1325 hotplug_hrtick_enable(cpu
);
1332 static void init_hrtick(void)
1334 hotcpu_notifier(hotplug_hrtick
, 0);
1337 static void init_rq_hrtick(struct rq
*rq
)
1339 rq
->hrtick_flags
= 0;
1340 hrtimer_init(&rq
->hrtick_timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1341 rq
->hrtick_timer
.function
= hrtick
;
1342 rq
->hrtick_timer
.cb_mode
= HRTIMER_CB_IRQSAFE_NO_SOFTIRQ
;
1345 void hrtick_resched(void)
1348 unsigned long flags
;
1350 if (!test_thread_flag(TIF_HRTICK_RESCHED
))
1353 local_irq_save(flags
);
1354 rq
= cpu_rq(smp_processor_id());
1356 local_irq_restore(flags
);
1359 static inline void hrtick_clear(struct rq
*rq
)
1363 static inline void hrtick_set(struct rq
*rq
)
1367 static inline void init_rq_hrtick(struct rq
*rq
)
1371 void hrtick_resched(void)
1375 static inline void init_hrtick(void)
1381 * resched_task - mark a task 'to be rescheduled now'.
1383 * On UP this means the setting of the need_resched flag, on SMP it
1384 * might also involve a cross-CPU call to trigger the scheduler on
1389 #ifndef tsk_is_polling
1390 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1393 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1397 assert_spin_locked(&task_rq(p
)->lock
);
1399 if (unlikely(test_tsk_thread_flag(p
, tif_bit
)))
1402 set_tsk_thread_flag(p
, tif_bit
);
1405 if (cpu
== smp_processor_id())
1408 /* NEED_RESCHED must be visible before we test polling */
1410 if (!tsk_is_polling(p
))
1411 smp_send_reschedule(cpu
);
1414 static void resched_cpu(int cpu
)
1416 struct rq
*rq
= cpu_rq(cpu
);
1417 unsigned long flags
;
1419 if (!spin_trylock_irqsave(&rq
->lock
, flags
))
1421 resched_task(cpu_curr(cpu
));
1422 spin_unlock_irqrestore(&rq
->lock
, flags
);
1427 * When add_timer_on() enqueues a timer into the timer wheel of an
1428 * idle CPU then this timer might expire before the next timer event
1429 * which is scheduled to wake up that CPU. In case of a completely
1430 * idle system the next event might even be infinite time into the
1431 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1432 * leaves the inner idle loop so the newly added timer is taken into
1433 * account when the CPU goes back to idle and evaluates the timer
1434 * wheel for the next timer event.
1436 void wake_up_idle_cpu(int cpu
)
1438 struct rq
*rq
= cpu_rq(cpu
);
1440 if (cpu
== smp_processor_id())
1444 * This is safe, as this function is called with the timer
1445 * wheel base lock of (cpu) held. When the CPU is on the way
1446 * to idle and has not yet set rq->curr to idle then it will
1447 * be serialized on the timer wheel base lock and take the new
1448 * timer into account automatically.
1450 if (rq
->curr
!= rq
->idle
)
1454 * We can set TIF_RESCHED on the idle task of the other CPU
1455 * lockless. The worst case is that the other CPU runs the
1456 * idle task through an additional NOOP schedule()
1458 set_tsk_thread_flag(rq
->idle
, TIF_NEED_RESCHED
);
1460 /* NEED_RESCHED must be visible before we test polling */
1462 if (!tsk_is_polling(rq
->idle
))
1463 smp_send_reschedule(cpu
);
1468 static void __resched_task(struct task_struct
*p
, int tif_bit
)
1470 assert_spin_locked(&task_rq(p
)->lock
);
1471 set_tsk_thread_flag(p
, tif_bit
);
1475 #if BITS_PER_LONG == 32
1476 # define WMULT_CONST (~0UL)
1478 # define WMULT_CONST (1UL << 32)
1481 #define WMULT_SHIFT 32
1484 * Shift right and round:
1486 #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
1489 * delta *= weight / lw
1491 static unsigned long
1492 calc_delta_mine(unsigned long delta_exec
, unsigned long weight
,
1493 struct load_weight
*lw
)
1497 if (!lw
->inv_weight
)
1498 lw
->inv_weight
= 1 + (WMULT_CONST
-lw
->weight
/2)/(lw
->weight
+1);
1500 tmp
= (u64
)delta_exec
* weight
;
1502 * Check whether we'd overflow the 64-bit multiplication:
1504 if (unlikely(tmp
> WMULT_CONST
))
1505 tmp
= SRR(SRR(tmp
, WMULT_SHIFT
/2) * lw
->inv_weight
,
1508 tmp
= SRR(tmp
* lw
->inv_weight
, WMULT_SHIFT
);
1510 return (unsigned long)min(tmp
, (u64
)(unsigned long)LONG_MAX
);
1513 static inline void update_load_add(struct load_weight
*lw
, unsigned long inc
)
1519 static inline void update_load_sub(struct load_weight
*lw
, unsigned long dec
)
1526 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1527 * of tasks with abnormal "nice" values across CPUs the contribution that
1528 * each task makes to its run queue's load is weighted according to its
1529 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
1530 * scaled version of the new time slice allocation that they receive on time
1534 #define WEIGHT_IDLEPRIO 2
1535 #define WMULT_IDLEPRIO (1 << 31)
1538 * Nice levels are multiplicative, with a gentle 10% change for every
1539 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1540 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1541 * that remained on nice 0.
1543 * The "10% effect" is relative and cumulative: from _any_ nice level,
1544 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
1545 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1546 * If a task goes up by ~10% and another task goes down by ~10% then
1547 * the relative distance between them is ~25%.)
1549 static const int prio_to_weight
[40] = {
1550 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1551 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1552 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1553 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1554 /* 0 */ 1024, 820, 655, 526, 423,
1555 /* 5 */ 335, 272, 215, 172, 137,
1556 /* 10 */ 110, 87, 70, 56, 45,
1557 /* 15 */ 36, 29, 23, 18, 15,
1561 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1563 * In cases where the weight does not change often, we can use the
1564 * precalculated inverse to speed up arithmetics by turning divisions
1565 * into multiplications:
1567 static const u32 prio_to_wmult
[40] = {
1568 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1569 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1570 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1571 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1572 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1573 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1574 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1575 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
1578 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
);
1581 * runqueue iterator, to support SMP load-balancing between different
1582 * scheduling classes, without having to expose their internal data
1583 * structures to the load-balancing proper:
1585 struct rq_iterator
{
1587 struct task_struct
*(*start
)(void *);
1588 struct task_struct
*(*next
)(void *);
1592 static unsigned long
1593 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1594 unsigned long max_load_move
, struct sched_domain
*sd
,
1595 enum cpu_idle_type idle
, int *all_pinned
,
1596 int *this_best_prio
, struct rq_iterator
*iterator
);
1599 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
1600 struct sched_domain
*sd
, enum cpu_idle_type idle
,
1601 struct rq_iterator
*iterator
);
1604 #ifdef CONFIG_CGROUP_CPUACCT
1605 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
);
1607 static inline void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
) {}
1610 static inline void inc_cpu_load(struct rq
*rq
, unsigned long load
)
1612 update_load_add(&rq
->load
, load
);
1615 static inline void dec_cpu_load(struct rq
*rq
, unsigned long load
)
1617 update_load_sub(&rq
->load
, load
);
1621 static unsigned long source_load(int cpu
, int type
);
1622 static unsigned long target_load(int cpu
, int type
);
1623 static unsigned long cpu_avg_load_per_task(int cpu
);
1624 static int task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
);
1626 #ifdef CONFIG_FAIR_GROUP_SCHED
1629 * Group load balancing.
1631 * We calculate a few balance domain wide aggregate numbers; load and weight.
1632 * Given the pictures below, and assuming each item has equal weight:
1643 * A and B get 1/3-rd of the total load. C and D get 1/3-rd of A's 1/3-rd,
1644 * which equals 1/9-th of the total load.
1647 * The weight of this group on the selected cpus.
1650 * Direct sum of all the cpu's their rq weight, e.g. A would get 3 while
1654 * Part of the rq_weight contributed by tasks; all groups except B would
1658 static inline struct aggregate_struct
*
1659 aggregate(struct task_group
*tg
, struct sched_domain
*sd
)
1661 return &tg
->cfs_rq
[sd
->first_cpu
]->aggregate
;
1664 typedef void (*aggregate_func
)(struct task_group
*, struct sched_domain
*);
1667 * Iterate the full tree, calling @down when first entering a node and @up when
1668 * leaving it for the final time.
1671 void aggregate_walk_tree(aggregate_func down
, aggregate_func up
,
1672 struct sched_domain
*sd
)
1674 struct task_group
*parent
, *child
;
1677 parent
= &root_task_group
;
1679 (*down
)(parent
, sd
);
1680 list_for_each_entry_rcu(child
, &parent
->children
, siblings
) {
1690 parent
= parent
->parent
;
1697 * Calculate the aggregate runqueue weight.
1700 void aggregate_group_weight(struct task_group
*tg
, struct sched_domain
*sd
)
1702 unsigned long rq_weight
= 0;
1703 unsigned long task_weight
= 0;
1706 for_each_cpu_mask(i
, sd
->span
) {
1707 rq_weight
+= tg
->cfs_rq
[i
]->load
.weight
;
1708 task_weight
+= tg
->cfs_rq
[i
]->task_weight
;
1711 aggregate(tg
, sd
)->rq_weight
= rq_weight
;
1712 aggregate(tg
, sd
)->task_weight
= task_weight
;
1716 * Compute the weight of this group on the given cpus.
1719 void aggregate_group_shares(struct task_group
*tg
, struct sched_domain
*sd
)
1721 unsigned long shares
= 0;
1724 for_each_cpu_mask(i
, sd
->span
)
1725 shares
+= tg
->cfs_rq
[i
]->shares
;
1727 if ((!shares
&& aggregate(tg
, sd
)->rq_weight
) || shares
> tg
->shares
)
1728 shares
= tg
->shares
;
1730 aggregate(tg
, sd
)->shares
= shares
;
1734 * Compute the load fraction assigned to this group, relies on the aggregate
1735 * weight and this group's parent's load, i.e. top-down.
1738 void aggregate_group_load(struct task_group
*tg
, struct sched_domain
*sd
)
1746 for_each_cpu_mask(i
, sd
->span
)
1747 load
+= cpu_rq(i
)->load
.weight
;
1750 load
= aggregate(tg
->parent
, sd
)->load
;
1753 * shares is our weight in the parent's rq so
1754 * shares/parent->rq_weight gives our fraction of the load
1756 load
*= aggregate(tg
, sd
)->shares
;
1757 load
/= aggregate(tg
->parent
, sd
)->rq_weight
+ 1;
1760 aggregate(tg
, sd
)->load
= load
;
1763 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
);
1766 * Calculate and set the cpu's group shares.
1769 __update_group_shares_cpu(struct task_group
*tg
, struct sched_domain
*sd
,
1773 unsigned long shares
;
1774 unsigned long rq_weight
;
1779 rq_weight
= tg
->cfs_rq
[tcpu
]->load
.weight
;
1782 * If there are currently no tasks on the cpu pretend there is one of
1783 * average load so that when a new task gets to run here it will not
1784 * get delayed by group starvation.
1788 rq_weight
= NICE_0_LOAD
;
1792 * \Sum shares * rq_weight
1793 * shares = -----------------------
1797 shares
= aggregate(tg
, sd
)->shares
* rq_weight
;
1798 shares
/= aggregate(tg
, sd
)->rq_weight
+ 1;
1801 * record the actual number of shares, not the boosted amount.
1803 tg
->cfs_rq
[tcpu
]->shares
= boost
? 0 : shares
;
1805 if (shares
< MIN_SHARES
)
1806 shares
= MIN_SHARES
;
1808 __set_se_shares(tg
->se
[tcpu
], shares
);
1812 * Re-adjust the weights on the cpu the task came from and on the cpu the
1816 __move_group_shares(struct task_group
*tg
, struct sched_domain
*sd
,
1819 unsigned long shares
;
1821 shares
= tg
->cfs_rq
[scpu
]->shares
+ tg
->cfs_rq
[dcpu
]->shares
;
1823 __update_group_shares_cpu(tg
, sd
, scpu
);
1824 __update_group_shares_cpu(tg
, sd
, dcpu
);
1827 * ensure we never loose shares due to rounding errors in the
1828 * above redistribution.
1830 shares
-= tg
->cfs_rq
[scpu
]->shares
+ tg
->cfs_rq
[dcpu
]->shares
;
1832 tg
->cfs_rq
[dcpu
]->shares
+= shares
;
1836 * Because changing a group's shares changes the weight of the super-group
1837 * we need to walk up the tree and change all shares until we hit the root.
1840 move_group_shares(struct task_group
*tg
, struct sched_domain
*sd
,
1844 __move_group_shares(tg
, sd
, scpu
, dcpu
);
1850 void aggregate_group_set_shares(struct task_group
*tg
, struct sched_domain
*sd
)
1852 unsigned long shares
= aggregate(tg
, sd
)->shares
;
1855 for_each_cpu_mask(i
, sd
->span
) {
1856 struct rq
*rq
= cpu_rq(i
);
1857 unsigned long flags
;
1859 spin_lock_irqsave(&rq
->lock
, flags
);
1860 __update_group_shares_cpu(tg
, sd
, i
);
1861 spin_unlock_irqrestore(&rq
->lock
, flags
);
1864 aggregate_group_shares(tg
, sd
);
1867 * ensure we never loose shares due to rounding errors in the
1868 * above redistribution.
1870 shares
-= aggregate(tg
, sd
)->shares
;
1872 tg
->cfs_rq
[sd
->first_cpu
]->shares
+= shares
;
1873 aggregate(tg
, sd
)->shares
+= shares
;
1878 * Calculate the accumulative weight and recursive load of each task group
1879 * while walking down the tree.
1882 void aggregate_get_down(struct task_group
*tg
, struct sched_domain
*sd
)
1884 aggregate_group_weight(tg
, sd
);
1885 aggregate_group_shares(tg
, sd
);
1886 aggregate_group_load(tg
, sd
);
1890 * Rebalance the cpu shares while walking back up the tree.
1893 void aggregate_get_up(struct task_group
*tg
, struct sched_domain
*sd
)
1895 aggregate_group_set_shares(tg
, sd
);
1898 static DEFINE_PER_CPU(spinlock_t
, aggregate_lock
);
1900 static void __init
init_aggregate(void)
1904 for_each_possible_cpu(i
)
1905 spin_lock_init(&per_cpu(aggregate_lock
, i
));
1908 static int get_aggregate(struct sched_domain
*sd
)
1910 if (!spin_trylock(&per_cpu(aggregate_lock
, sd
->first_cpu
)))
1913 aggregate_walk_tree(aggregate_get_down
, aggregate_get_up
, sd
);
1917 static void put_aggregate(struct sched_domain
*sd
)
1919 spin_unlock(&per_cpu(aggregate_lock
, sd
->first_cpu
));
1922 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1924 cfs_rq
->shares
= shares
;
1929 static inline void init_aggregate(void)
1933 static inline int get_aggregate(struct sched_domain
*sd
)
1938 static inline void put_aggregate(struct sched_domain
*sd
)
1943 #else /* CONFIG_SMP */
1945 #ifdef CONFIG_FAIR_GROUP_SCHED
1946 static void cfs_rq_set_shares(struct cfs_rq
*cfs_rq
, unsigned long shares
)
1951 #endif /* CONFIG_SMP */
1953 #include "sched_stats.h"
1954 #include "sched_idletask.c"
1955 #include "sched_fair.c"
1956 #include "sched_rt.c"
1957 #ifdef CONFIG_SCHED_DEBUG
1958 # include "sched_debug.c"
1961 #define sched_class_highest (&rt_sched_class)
1963 static void inc_nr_running(struct rq
*rq
)
1968 static void dec_nr_running(struct rq
*rq
)
1973 static void set_load_weight(struct task_struct
*p
)
1975 if (task_has_rt_policy(p
)) {
1976 p
->se
.load
.weight
= prio_to_weight
[0] * 2;
1977 p
->se
.load
.inv_weight
= prio_to_wmult
[0] >> 1;
1982 * SCHED_IDLE tasks get minimal weight:
1984 if (p
->policy
== SCHED_IDLE
) {
1985 p
->se
.load
.weight
= WEIGHT_IDLEPRIO
;
1986 p
->se
.load
.inv_weight
= WMULT_IDLEPRIO
;
1990 p
->se
.load
.weight
= prio_to_weight
[p
->static_prio
- MAX_RT_PRIO
];
1991 p
->se
.load
.inv_weight
= prio_to_wmult
[p
->static_prio
- MAX_RT_PRIO
];
1994 static void enqueue_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
1996 sched_info_queued(p
);
1997 p
->sched_class
->enqueue_task(rq
, p
, wakeup
);
2001 static void dequeue_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
2003 p
->sched_class
->dequeue_task(rq
, p
, sleep
);
2008 * __normal_prio - return the priority that is based on the static prio
2010 static inline int __normal_prio(struct task_struct
*p
)
2012 return p
->static_prio
;
2016 * Calculate the expected normal priority: i.e. priority
2017 * without taking RT-inheritance into account. Might be
2018 * boosted by interactivity modifiers. Changes upon fork,
2019 * setprio syscalls, and whenever the interactivity
2020 * estimator recalculates.
2022 static inline int normal_prio(struct task_struct
*p
)
2026 if (task_has_rt_policy(p
))
2027 prio
= MAX_RT_PRIO
-1 - p
->rt_priority
;
2029 prio
= __normal_prio(p
);
2034 * Calculate the current priority, i.e. the priority
2035 * taken into account by the scheduler. This value might
2036 * be boosted by RT tasks, or might be boosted by
2037 * interactivity modifiers. Will be RT if the task got
2038 * RT-boosted. If not then it returns p->normal_prio.
2040 static int effective_prio(struct task_struct
*p
)
2042 p
->normal_prio
= normal_prio(p
);
2044 * If we are RT tasks or we were boosted to RT priority,
2045 * keep the priority unchanged. Otherwise, update priority
2046 * to the normal priority:
2048 if (!rt_prio(p
->prio
))
2049 return p
->normal_prio
;
2054 * activate_task - move a task to the runqueue.
2056 static void activate_task(struct rq
*rq
, struct task_struct
*p
, int wakeup
)
2058 if (task_contributes_to_load(p
))
2059 rq
->nr_uninterruptible
--;
2061 enqueue_task(rq
, p
, wakeup
);
2066 * deactivate_task - remove a task from the runqueue.
2068 static void deactivate_task(struct rq
*rq
, struct task_struct
*p
, int sleep
)
2070 if (task_contributes_to_load(p
))
2071 rq
->nr_uninterruptible
++;
2073 dequeue_task(rq
, p
, sleep
);
2078 * task_curr - is this task currently executing on a CPU?
2079 * @p: the task in question.
2081 inline int task_curr(const struct task_struct
*p
)
2083 return cpu_curr(task_cpu(p
)) == p
;
2086 /* Used instead of source_load when we know the type == 0 */
2087 unsigned long weighted_cpuload(const int cpu
)
2089 return cpu_rq(cpu
)->load
.weight
;
2092 static inline void __set_task_cpu(struct task_struct
*p
, unsigned int cpu
)
2094 set_task_rq(p
, cpu
);
2097 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
2098 * successfuly executed on another CPU. We must ensure that updates of
2099 * per-task data have been completed by this moment.
2102 task_thread_info(p
)->cpu
= cpu
;
2106 static inline void check_class_changed(struct rq
*rq
, struct task_struct
*p
,
2107 const struct sched_class
*prev_class
,
2108 int oldprio
, int running
)
2110 if (prev_class
!= p
->sched_class
) {
2111 if (prev_class
->switched_from
)
2112 prev_class
->switched_from(rq
, p
, running
);
2113 p
->sched_class
->switched_to(rq
, p
, running
);
2115 p
->sched_class
->prio_changed(rq
, p
, oldprio
, running
);
2121 * Is this task likely cache-hot:
2124 task_hot(struct task_struct
*p
, u64 now
, struct sched_domain
*sd
)
2129 * Buddy candidates are cache hot:
2131 if (sched_feat(CACHE_HOT_BUDDY
) && (&p
->se
== cfs_rq_of(&p
->se
)->next
))
2134 if (p
->sched_class
!= &fair_sched_class
)
2137 if (sysctl_sched_migration_cost
== -1)
2139 if (sysctl_sched_migration_cost
== 0)
2142 delta
= now
- p
->se
.exec_start
;
2144 return delta
< (s64
)sysctl_sched_migration_cost
;
2148 void set_task_cpu(struct task_struct
*p
, unsigned int new_cpu
)
2150 int old_cpu
= task_cpu(p
);
2151 struct rq
*old_rq
= cpu_rq(old_cpu
), *new_rq
= cpu_rq(new_cpu
);
2152 struct cfs_rq
*old_cfsrq
= task_cfs_rq(p
),
2153 *new_cfsrq
= cpu_cfs_rq(old_cfsrq
, new_cpu
);
2156 clock_offset
= old_rq
->clock
- new_rq
->clock
;
2158 #ifdef CONFIG_SCHEDSTATS
2159 if (p
->se
.wait_start
)
2160 p
->se
.wait_start
-= clock_offset
;
2161 if (p
->se
.sleep_start
)
2162 p
->se
.sleep_start
-= clock_offset
;
2163 if (p
->se
.block_start
)
2164 p
->se
.block_start
-= clock_offset
;
2165 if (old_cpu
!= new_cpu
) {
2166 schedstat_inc(p
, se
.nr_migrations
);
2167 if (task_hot(p
, old_rq
->clock
, NULL
))
2168 schedstat_inc(p
, se
.nr_forced2_migrations
);
2171 p
->se
.vruntime
-= old_cfsrq
->min_vruntime
-
2172 new_cfsrq
->min_vruntime
;
2174 __set_task_cpu(p
, new_cpu
);
2177 struct migration_req
{
2178 struct list_head list
;
2180 struct task_struct
*task
;
2183 struct completion done
;
2187 * The task's runqueue lock must be held.
2188 * Returns true if you have to wait for migration thread.
2191 migrate_task(struct task_struct
*p
, int dest_cpu
, struct migration_req
*req
)
2193 struct rq
*rq
= task_rq(p
);
2196 * If the task is not on a runqueue (and not running), then
2197 * it is sufficient to simply update the task's cpu field.
2199 if (!p
->se
.on_rq
&& !task_running(rq
, p
)) {
2200 set_task_cpu(p
, dest_cpu
);
2204 init_completion(&req
->done
);
2206 req
->dest_cpu
= dest_cpu
;
2207 list_add(&req
->list
, &rq
->migration_queue
);
2213 * wait_task_inactive - wait for a thread to unschedule.
2215 * The caller must ensure that the task *will* unschedule sometime soon,
2216 * else this function might spin for a *long* time. This function can't
2217 * be called with interrupts off, or it may introduce deadlock with
2218 * smp_call_function() if an IPI is sent by the same process we are
2219 * waiting to become inactive.
2221 void wait_task_inactive(struct task_struct
*p
)
2223 unsigned long flags
;
2229 * We do the initial early heuristics without holding
2230 * any task-queue locks at all. We'll only try to get
2231 * the runqueue lock when things look like they will
2237 * If the task is actively running on another CPU
2238 * still, just relax and busy-wait without holding
2241 * NOTE! Since we don't hold any locks, it's not
2242 * even sure that "rq" stays as the right runqueue!
2243 * But we don't care, since "task_running()" will
2244 * return false if the runqueue has changed and p
2245 * is actually now running somewhere else!
2247 while (task_running(rq
, p
))
2251 * Ok, time to look more closely! We need the rq
2252 * lock now, to be *sure*. If we're wrong, we'll
2253 * just go back and repeat.
2255 rq
= task_rq_lock(p
, &flags
);
2256 running
= task_running(rq
, p
);
2257 on_rq
= p
->se
.on_rq
;
2258 task_rq_unlock(rq
, &flags
);
2261 * Was it really running after all now that we
2262 * checked with the proper locks actually held?
2264 * Oops. Go back and try again..
2266 if (unlikely(running
)) {
2272 * It's not enough that it's not actively running,
2273 * it must be off the runqueue _entirely_, and not
2276 * So if it wa still runnable (but just not actively
2277 * running right now), it's preempted, and we should
2278 * yield - it could be a while.
2280 if (unlikely(on_rq
)) {
2281 schedule_timeout_uninterruptible(1);
2286 * Ahh, all good. It wasn't running, and it wasn't
2287 * runnable, which means that it will never become
2288 * running in the future either. We're all done!
2295 * kick_process - kick a running thread to enter/exit the kernel
2296 * @p: the to-be-kicked thread
2298 * Cause a process which is running on another CPU to enter
2299 * kernel-mode, without any delay. (to get signals handled.)
2301 * NOTE: this function doesnt have to take the runqueue lock,
2302 * because all it wants to ensure is that the remote task enters
2303 * the kernel. If the IPI races and the task has been migrated
2304 * to another CPU then no harm is done and the purpose has been
2307 void kick_process(struct task_struct
*p
)
2313 if ((cpu
!= smp_processor_id()) && task_curr(p
))
2314 smp_send_reschedule(cpu
);
2319 * Return a low guess at the load of a migration-source cpu weighted
2320 * according to the scheduling class and "nice" value.
2322 * We want to under-estimate the load of migration sources, to
2323 * balance conservatively.
2325 static unsigned long source_load(int cpu
, int type
)
2327 struct rq
*rq
= cpu_rq(cpu
);
2328 unsigned long total
= weighted_cpuload(cpu
);
2333 return min(rq
->cpu_load
[type
-1], total
);
2337 * Return a high guess at the load of a migration-target cpu weighted
2338 * according to the scheduling class and "nice" value.
2340 static unsigned long target_load(int cpu
, int type
)
2342 struct rq
*rq
= cpu_rq(cpu
);
2343 unsigned long total
= weighted_cpuload(cpu
);
2348 return max(rq
->cpu_load
[type
-1], total
);
2352 * Return the average load per task on the cpu's run queue
2354 static unsigned long cpu_avg_load_per_task(int cpu
)
2356 struct rq
*rq
= cpu_rq(cpu
);
2357 unsigned long total
= weighted_cpuload(cpu
);
2358 unsigned long n
= rq
->nr_running
;
2360 return n
? total
/ n
: SCHED_LOAD_SCALE
;
2364 * find_idlest_group finds and returns the least busy CPU group within the
2367 static struct sched_group
*
2368 find_idlest_group(struct sched_domain
*sd
, struct task_struct
*p
, int this_cpu
)
2370 struct sched_group
*idlest
= NULL
, *this = NULL
, *group
= sd
->groups
;
2371 unsigned long min_load
= ULONG_MAX
, this_load
= 0;
2372 int load_idx
= sd
->forkexec_idx
;
2373 int imbalance
= 100 + (sd
->imbalance_pct
-100)/2;
2376 unsigned long load
, avg_load
;
2380 /* Skip over this group if it has no CPUs allowed */
2381 if (!cpus_intersects(group
->cpumask
, p
->cpus_allowed
))
2384 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
2386 /* Tally up the load of all CPUs in the group */
2389 for_each_cpu_mask(i
, group
->cpumask
) {
2390 /* Bias balancing toward cpus of our domain */
2392 load
= source_load(i
, load_idx
);
2394 load
= target_load(i
, load_idx
);
2399 /* Adjust by relative CPU power of the group */
2400 avg_load
= sg_div_cpu_power(group
,
2401 avg_load
* SCHED_LOAD_SCALE
);
2404 this_load
= avg_load
;
2406 } else if (avg_load
< min_load
) {
2407 min_load
= avg_load
;
2410 } while (group
= group
->next
, group
!= sd
->groups
);
2412 if (!idlest
|| 100*this_load
< imbalance
*min_load
)
2418 * find_idlest_cpu - find the idlest cpu among the cpus in group.
2421 find_idlest_cpu(struct sched_group
*group
, struct task_struct
*p
, int this_cpu
,
2424 unsigned long load
, min_load
= ULONG_MAX
;
2428 /* Traverse only the allowed CPUs */
2429 cpus_and(*tmp
, group
->cpumask
, p
->cpus_allowed
);
2431 for_each_cpu_mask(i
, *tmp
) {
2432 load
= weighted_cpuload(i
);
2434 if (load
< min_load
|| (load
== min_load
&& i
== this_cpu
)) {
2444 * sched_balance_self: balance the current task (running on cpu) in domains
2445 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2448 * Balance, ie. select the least loaded group.
2450 * Returns the target CPU number, or the same CPU if no balancing is needed.
2452 * preempt must be disabled.
2454 static int sched_balance_self(int cpu
, int flag
)
2456 struct task_struct
*t
= current
;
2457 struct sched_domain
*tmp
, *sd
= NULL
;
2459 for_each_domain(cpu
, tmp
) {
2461 * If power savings logic is enabled for a domain, stop there.
2463 if (tmp
->flags
& SD_POWERSAVINGS_BALANCE
)
2465 if (tmp
->flags
& flag
)
2470 cpumask_t span
, tmpmask
;
2471 struct sched_group
*group
;
2472 int new_cpu
, weight
;
2474 if (!(sd
->flags
& flag
)) {
2480 group
= find_idlest_group(sd
, t
, cpu
);
2486 new_cpu
= find_idlest_cpu(group
, t
, cpu
, &tmpmask
);
2487 if (new_cpu
== -1 || new_cpu
== cpu
) {
2488 /* Now try balancing at a lower domain level of cpu */
2493 /* Now try balancing at a lower domain level of new_cpu */
2496 weight
= cpus_weight(span
);
2497 for_each_domain(cpu
, tmp
) {
2498 if (weight
<= cpus_weight(tmp
->span
))
2500 if (tmp
->flags
& flag
)
2503 /* while loop will break here if sd == NULL */
2509 #endif /* CONFIG_SMP */
2512 * try_to_wake_up - wake up a thread
2513 * @p: the to-be-woken-up thread
2514 * @state: the mask of task states that can be woken
2515 * @sync: do a synchronous wakeup?
2517 * Put it on the run-queue if it's not already there. The "current"
2518 * thread is always on the run-queue (except when the actual
2519 * re-schedule is in progress), and as such you're allowed to do
2520 * the simpler "current->state = TASK_RUNNING" to mark yourself
2521 * runnable without the overhead of this.
2523 * returns failure only if the task is already active.
2525 static int try_to_wake_up(struct task_struct
*p
, unsigned int state
, int sync
)
2527 int cpu
, orig_cpu
, this_cpu
, success
= 0;
2528 unsigned long flags
;
2532 if (!sched_feat(SYNC_WAKEUPS
))
2536 rq
= task_rq_lock(p
, &flags
);
2537 old_state
= p
->state
;
2538 if (!(old_state
& state
))
2546 this_cpu
= smp_processor_id();
2549 if (unlikely(task_running(rq
, p
)))
2552 cpu
= p
->sched_class
->select_task_rq(p
, sync
);
2553 if (cpu
!= orig_cpu
) {
2554 set_task_cpu(p
, cpu
);
2555 task_rq_unlock(rq
, &flags
);
2556 /* might preempt at this point */
2557 rq
= task_rq_lock(p
, &flags
);
2558 old_state
= p
->state
;
2559 if (!(old_state
& state
))
2564 this_cpu
= smp_processor_id();
2568 #ifdef CONFIG_SCHEDSTATS
2569 schedstat_inc(rq
, ttwu_count
);
2570 if (cpu
== this_cpu
)
2571 schedstat_inc(rq
, ttwu_local
);
2573 struct sched_domain
*sd
;
2574 for_each_domain(this_cpu
, sd
) {
2575 if (cpu_isset(cpu
, sd
->span
)) {
2576 schedstat_inc(sd
, ttwu_wake_remote
);
2584 #endif /* CONFIG_SMP */
2585 schedstat_inc(p
, se
.nr_wakeups
);
2587 schedstat_inc(p
, se
.nr_wakeups_sync
);
2588 if (orig_cpu
!= cpu
)
2589 schedstat_inc(p
, se
.nr_wakeups_migrate
);
2590 if (cpu
== this_cpu
)
2591 schedstat_inc(p
, se
.nr_wakeups_local
);
2593 schedstat_inc(p
, se
.nr_wakeups_remote
);
2594 update_rq_clock(rq
);
2595 activate_task(rq
, p
, 1);
2599 check_preempt_curr(rq
, p
);
2601 p
->state
= TASK_RUNNING
;
2603 if (p
->sched_class
->task_wake_up
)
2604 p
->sched_class
->task_wake_up(rq
, p
);
2607 task_rq_unlock(rq
, &flags
);
2612 int wake_up_process(struct task_struct
*p
)
2614 return try_to_wake_up(p
, TASK_ALL
, 0);
2616 EXPORT_SYMBOL(wake_up_process
);
2618 int wake_up_state(struct task_struct
*p
, unsigned int state
)
2620 return try_to_wake_up(p
, state
, 0);
2624 * Perform scheduler related setup for a newly forked process p.
2625 * p is forked by current.
2627 * __sched_fork() is basic setup used by init_idle() too:
2629 static void __sched_fork(struct task_struct
*p
)
2631 p
->se
.exec_start
= 0;
2632 p
->se
.sum_exec_runtime
= 0;
2633 p
->se
.prev_sum_exec_runtime
= 0;
2634 p
->se
.last_wakeup
= 0;
2635 p
->se
.avg_overlap
= 0;
2637 #ifdef CONFIG_SCHEDSTATS
2638 p
->se
.wait_start
= 0;
2639 p
->se
.sum_sleep_runtime
= 0;
2640 p
->se
.sleep_start
= 0;
2641 p
->se
.block_start
= 0;
2642 p
->se
.sleep_max
= 0;
2643 p
->se
.block_max
= 0;
2645 p
->se
.slice_max
= 0;
2649 INIT_LIST_HEAD(&p
->rt
.run_list
);
2651 INIT_LIST_HEAD(&p
->se
.group_node
);
2653 #ifdef CONFIG_PREEMPT_NOTIFIERS
2654 INIT_HLIST_HEAD(&p
->preempt_notifiers
);
2658 * We mark the process as running here, but have not actually
2659 * inserted it onto the runqueue yet. This guarantees that
2660 * nobody will actually run it, and a signal or other external
2661 * event cannot wake it up and insert it on the runqueue either.
2663 p
->state
= TASK_RUNNING
;
2667 * fork()/clone()-time setup:
2669 void sched_fork(struct task_struct
*p
, int clone_flags
)
2671 int cpu
= get_cpu();
2676 cpu
= sched_balance_self(cpu
, SD_BALANCE_FORK
);
2678 set_task_cpu(p
, cpu
);
2681 * Make sure we do not leak PI boosting priority to the child:
2683 p
->prio
= current
->normal_prio
;
2684 if (!rt_prio(p
->prio
))
2685 p
->sched_class
= &fair_sched_class
;
2687 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
2688 if (likely(sched_info_on()))
2689 memset(&p
->sched_info
, 0, sizeof(p
->sched_info
));
2691 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
2694 #ifdef CONFIG_PREEMPT
2695 /* Want to start with kernel preemption disabled. */
2696 task_thread_info(p
)->preempt_count
= 1;
2702 * wake_up_new_task - wake up a newly created task for the first time.
2704 * This function will do some initial scheduler statistics housekeeping
2705 * that must be done for every newly created context, then puts the task
2706 * on the runqueue and wakes it.
2708 void wake_up_new_task(struct task_struct
*p
, unsigned long clone_flags
)
2710 unsigned long flags
;
2713 rq
= task_rq_lock(p
, &flags
);
2714 BUG_ON(p
->state
!= TASK_RUNNING
);
2715 update_rq_clock(rq
);
2717 p
->prio
= effective_prio(p
);
2719 if (!p
->sched_class
->task_new
|| !current
->se
.on_rq
) {
2720 activate_task(rq
, p
, 0);
2723 * Let the scheduling class do new task startup
2724 * management (if any):
2726 p
->sched_class
->task_new(rq
, p
);
2729 check_preempt_curr(rq
, p
);
2731 if (p
->sched_class
->task_wake_up
)
2732 p
->sched_class
->task_wake_up(rq
, p
);
2734 task_rq_unlock(rq
, &flags
);
2737 #ifdef CONFIG_PREEMPT_NOTIFIERS
2740 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2741 * @notifier: notifier struct to register
2743 void preempt_notifier_register(struct preempt_notifier
*notifier
)
2745 hlist_add_head(¬ifier
->link
, ¤t
->preempt_notifiers
);
2747 EXPORT_SYMBOL_GPL(preempt_notifier_register
);
2750 * preempt_notifier_unregister - no longer interested in preemption notifications
2751 * @notifier: notifier struct to unregister
2753 * This is safe to call from within a preemption notifier.
2755 void preempt_notifier_unregister(struct preempt_notifier
*notifier
)
2757 hlist_del(¬ifier
->link
);
2759 EXPORT_SYMBOL_GPL(preempt_notifier_unregister
);
2761 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2763 struct preempt_notifier
*notifier
;
2764 struct hlist_node
*node
;
2766 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2767 notifier
->ops
->sched_in(notifier
, raw_smp_processor_id());
2771 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2772 struct task_struct
*next
)
2774 struct preempt_notifier
*notifier
;
2775 struct hlist_node
*node
;
2777 hlist_for_each_entry(notifier
, node
, &curr
->preempt_notifiers
, link
)
2778 notifier
->ops
->sched_out(notifier
, next
);
2783 static void fire_sched_in_preempt_notifiers(struct task_struct
*curr
)
2788 fire_sched_out_preempt_notifiers(struct task_struct
*curr
,
2789 struct task_struct
*next
)
2796 * prepare_task_switch - prepare to switch tasks
2797 * @rq: the runqueue preparing to switch
2798 * @prev: the current task that is being switched out
2799 * @next: the task we are going to switch to.
2801 * This is called with the rq lock held and interrupts off. It must
2802 * be paired with a subsequent finish_task_switch after the context
2805 * prepare_task_switch sets up locking and calls architecture specific
2809 prepare_task_switch(struct rq
*rq
, struct task_struct
*prev
,
2810 struct task_struct
*next
)
2812 fire_sched_out_preempt_notifiers(prev
, next
);
2813 prepare_lock_switch(rq
, next
);
2814 prepare_arch_switch(next
);
2818 * finish_task_switch - clean up after a task-switch
2819 * @rq: runqueue associated with task-switch
2820 * @prev: the thread we just switched away from.
2822 * finish_task_switch must be called after the context switch, paired
2823 * with a prepare_task_switch call before the context switch.
2824 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2825 * and do any other architecture-specific cleanup actions.
2827 * Note that we may have delayed dropping an mm in context_switch(). If
2828 * so, we finish that here outside of the runqueue lock. (Doing it
2829 * with the lock held can cause deadlocks; see schedule() for
2832 static void finish_task_switch(struct rq
*rq
, struct task_struct
*prev
)
2833 __releases(rq
->lock
)
2835 struct mm_struct
*mm
= rq
->prev_mm
;
2841 * A task struct has one reference for the use as "current".
2842 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
2843 * schedule one last time. The schedule call will never return, and
2844 * the scheduled task must drop that reference.
2845 * The test for TASK_DEAD must occur while the runqueue locks are
2846 * still held, otherwise prev could be scheduled on another cpu, die
2847 * there before we look at prev->state, and then the reference would
2849 * Manfred Spraul <manfred@colorfullife.com>
2851 prev_state
= prev
->state
;
2852 finish_arch_switch(prev
);
2853 finish_lock_switch(rq
, prev
);
2855 if (current
->sched_class
->post_schedule
)
2856 current
->sched_class
->post_schedule(rq
);
2859 fire_sched_in_preempt_notifiers(current
);
2862 if (unlikely(prev_state
== TASK_DEAD
)) {
2864 * Remove function-return probe instances associated with this
2865 * task and put them back on the free list.
2867 kprobe_flush_task(prev
);
2868 put_task_struct(prev
);
2873 * schedule_tail - first thing a freshly forked thread must call.
2874 * @prev: the thread we just switched away from.
2876 asmlinkage
void schedule_tail(struct task_struct
*prev
)
2877 __releases(rq
->lock
)
2879 struct rq
*rq
= this_rq();
2881 finish_task_switch(rq
, prev
);
2882 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
2883 /* In this case, finish_task_switch does not reenable preemption */
2886 if (current
->set_child_tid
)
2887 put_user(task_pid_vnr(current
), current
->set_child_tid
);
2891 * context_switch - switch to the new MM and the new
2892 * thread's register state.
2895 context_switch(struct rq
*rq
, struct task_struct
*prev
,
2896 struct task_struct
*next
)
2898 struct mm_struct
*mm
, *oldmm
;
2900 prepare_task_switch(rq
, prev
, next
);
2902 oldmm
= prev
->active_mm
;
2904 * For paravirt, this is coupled with an exit in switch_to to
2905 * combine the page table reload and the switch backend into
2908 arch_enter_lazy_cpu_mode();
2910 if (unlikely(!mm
)) {
2911 next
->active_mm
= oldmm
;
2912 atomic_inc(&oldmm
->mm_count
);
2913 enter_lazy_tlb(oldmm
, next
);
2915 switch_mm(oldmm
, mm
, next
);
2917 if (unlikely(!prev
->mm
)) {
2918 prev
->active_mm
= NULL
;
2919 rq
->prev_mm
= oldmm
;
2922 * Since the runqueue lock will be released by the next
2923 * task (which is an invalid locking op but in the case
2924 * of the scheduler it's an obvious special-case), so we
2925 * do an early lockdep release here:
2927 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
2928 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
2931 /* Here we just switch the register state and the stack. */
2932 switch_to(prev
, next
, prev
);
2936 * this_rq must be evaluated again because prev may have moved
2937 * CPUs since it called schedule(), thus the 'rq' on its stack
2938 * frame will be invalid.
2940 finish_task_switch(this_rq(), prev
);
2944 * nr_running, nr_uninterruptible and nr_context_switches:
2946 * externally visible scheduler statistics: current number of runnable
2947 * threads, current number of uninterruptible-sleeping threads, total
2948 * number of context switches performed since bootup.
2950 unsigned long nr_running(void)
2952 unsigned long i
, sum
= 0;
2954 for_each_online_cpu(i
)
2955 sum
+= cpu_rq(i
)->nr_running
;
2960 unsigned long nr_uninterruptible(void)
2962 unsigned long i
, sum
= 0;
2964 for_each_possible_cpu(i
)
2965 sum
+= cpu_rq(i
)->nr_uninterruptible
;
2968 * Since we read the counters lockless, it might be slightly
2969 * inaccurate. Do not allow it to go below zero though:
2971 if (unlikely((long)sum
< 0))
2977 unsigned long long nr_context_switches(void)
2980 unsigned long long sum
= 0;
2982 for_each_possible_cpu(i
)
2983 sum
+= cpu_rq(i
)->nr_switches
;
2988 unsigned long nr_iowait(void)
2990 unsigned long i
, sum
= 0;
2992 for_each_possible_cpu(i
)
2993 sum
+= atomic_read(&cpu_rq(i
)->nr_iowait
);
2998 unsigned long nr_active(void)
3000 unsigned long i
, running
= 0, uninterruptible
= 0;
3002 for_each_online_cpu(i
) {
3003 running
+= cpu_rq(i
)->nr_running
;
3004 uninterruptible
+= cpu_rq(i
)->nr_uninterruptible
;
3007 if (unlikely((long)uninterruptible
< 0))
3008 uninterruptible
= 0;
3010 return running
+ uninterruptible
;
3014 * Update rq->cpu_load[] statistics. This function is usually called every
3015 * scheduler tick (TICK_NSEC).
3017 static void update_cpu_load(struct rq
*this_rq
)
3019 unsigned long this_load
= this_rq
->load
.weight
;
3022 this_rq
->nr_load_updates
++;
3024 /* Update our load: */
3025 for (i
= 0, scale
= 1; i
< CPU_LOAD_IDX_MAX
; i
++, scale
+= scale
) {
3026 unsigned long old_load
, new_load
;
3028 /* scale is effectively 1 << i now, and >> i divides by scale */
3030 old_load
= this_rq
->cpu_load
[i
];
3031 new_load
= this_load
;
3033 * Round up the averaging division if load is increasing. This
3034 * prevents us from getting stuck on 9 if the load is 10, for
3037 if (new_load
> old_load
)
3038 new_load
+= scale
-1;
3039 this_rq
->cpu_load
[i
] = (old_load
*(scale
-1) + new_load
) >> i
;
3046 * double_rq_lock - safely lock two runqueues
3048 * Note this does not disable interrupts like task_rq_lock,
3049 * you need to do so manually before calling.
3051 static void double_rq_lock(struct rq
*rq1
, struct rq
*rq2
)
3052 __acquires(rq1
->lock
)
3053 __acquires(rq2
->lock
)
3055 BUG_ON(!irqs_disabled());
3057 spin_lock(&rq1
->lock
);
3058 __acquire(rq2
->lock
); /* Fake it out ;) */
3061 spin_lock(&rq1
->lock
);
3062 spin_lock(&rq2
->lock
);
3064 spin_lock(&rq2
->lock
);
3065 spin_lock(&rq1
->lock
);
3068 update_rq_clock(rq1
);
3069 update_rq_clock(rq2
);
3073 * double_rq_unlock - safely unlock two runqueues
3075 * Note this does not restore interrupts like task_rq_unlock,
3076 * you need to do so manually after calling.
3078 static void double_rq_unlock(struct rq
*rq1
, struct rq
*rq2
)
3079 __releases(rq1
->lock
)
3080 __releases(rq2
->lock
)
3082 spin_unlock(&rq1
->lock
);
3084 spin_unlock(&rq2
->lock
);
3086 __release(rq2
->lock
);
3090 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
3092 static int double_lock_balance(struct rq
*this_rq
, struct rq
*busiest
)
3093 __releases(this_rq
->lock
)
3094 __acquires(busiest
->lock
)
3095 __acquires(this_rq
->lock
)
3099 if (unlikely(!irqs_disabled())) {
3100 /* printk() doesn't work good under rq->lock */
3101 spin_unlock(&this_rq
->lock
);
3104 if (unlikely(!spin_trylock(&busiest
->lock
))) {
3105 if (busiest
< this_rq
) {
3106 spin_unlock(&this_rq
->lock
);
3107 spin_lock(&busiest
->lock
);
3108 spin_lock(&this_rq
->lock
);
3111 spin_lock(&busiest
->lock
);
3117 * If dest_cpu is allowed for this process, migrate the task to it.
3118 * This is accomplished by forcing the cpu_allowed mask to only
3119 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
3120 * the cpu_allowed mask is restored.
3122 static void sched_migrate_task(struct task_struct
*p
, int dest_cpu
)
3124 struct migration_req req
;
3125 unsigned long flags
;
3128 rq
= task_rq_lock(p
, &flags
);
3129 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
)
3130 || unlikely(cpu_is_offline(dest_cpu
)))
3133 /* force the process onto the specified CPU */
3134 if (migrate_task(p
, dest_cpu
, &req
)) {
3135 /* Need to wait for migration thread (might exit: take ref). */
3136 struct task_struct
*mt
= rq
->migration_thread
;
3138 get_task_struct(mt
);
3139 task_rq_unlock(rq
, &flags
);
3140 wake_up_process(mt
);
3141 put_task_struct(mt
);
3142 wait_for_completion(&req
.done
);
3147 task_rq_unlock(rq
, &flags
);
3151 * sched_exec - execve() is a valuable balancing opportunity, because at
3152 * this point the task has the smallest effective memory and cache footprint.
3154 void sched_exec(void)
3156 int new_cpu
, this_cpu
= get_cpu();
3157 new_cpu
= sched_balance_self(this_cpu
, SD_BALANCE_EXEC
);
3159 if (new_cpu
!= this_cpu
)
3160 sched_migrate_task(current
, new_cpu
);
3164 * pull_task - move a task from a remote runqueue to the local runqueue.
3165 * Both runqueues must be locked.
3167 static void pull_task(struct rq
*src_rq
, struct task_struct
*p
,
3168 struct rq
*this_rq
, int this_cpu
)
3170 deactivate_task(src_rq
, p
, 0);
3171 set_task_cpu(p
, this_cpu
);
3172 activate_task(this_rq
, p
, 0);
3174 * Note that idle threads have a prio of MAX_PRIO, for this test
3175 * to be always true for them.
3177 check_preempt_curr(this_rq
, p
);
3181 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
3184 int can_migrate_task(struct task_struct
*p
, struct rq
*rq
, int this_cpu
,
3185 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3189 * We do not migrate tasks that are:
3190 * 1) running (obviously), or
3191 * 2) cannot be migrated to this CPU due to cpus_allowed, or
3192 * 3) are cache-hot on their current CPU.
3194 if (!cpu_isset(this_cpu
, p
->cpus_allowed
)) {
3195 schedstat_inc(p
, se
.nr_failed_migrations_affine
);
3200 if (task_running(rq
, p
)) {
3201 schedstat_inc(p
, se
.nr_failed_migrations_running
);
3206 * Aggressive migration if:
3207 * 1) task is cache cold, or
3208 * 2) too many balance attempts have failed.
3211 if (!task_hot(p
, rq
->clock
, sd
) ||
3212 sd
->nr_balance_failed
> sd
->cache_nice_tries
) {
3213 #ifdef CONFIG_SCHEDSTATS
3214 if (task_hot(p
, rq
->clock
, sd
)) {
3215 schedstat_inc(sd
, lb_hot_gained
[idle
]);
3216 schedstat_inc(p
, se
.nr_forced_migrations
);
3222 if (task_hot(p
, rq
->clock
, sd
)) {
3223 schedstat_inc(p
, se
.nr_failed_migrations_hot
);
3229 static unsigned long
3230 balance_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3231 unsigned long max_load_move
, struct sched_domain
*sd
,
3232 enum cpu_idle_type idle
, int *all_pinned
,
3233 int *this_best_prio
, struct rq_iterator
*iterator
)
3235 int loops
= 0, pulled
= 0, pinned
= 0, skip_for_load
;
3236 struct task_struct
*p
;
3237 long rem_load_move
= max_load_move
;
3239 if (max_load_move
== 0)
3245 * Start the load-balancing iterator:
3247 p
= iterator
->start(iterator
->arg
);
3249 if (!p
|| loops
++ > sysctl_sched_nr_migrate
)
3252 * To help distribute high priority tasks across CPUs we don't
3253 * skip a task if it will be the highest priority task (i.e. smallest
3254 * prio value) on its new queue regardless of its load weight
3256 skip_for_load
= (p
->se
.load
.weight
>> 1) > rem_load_move
+
3257 SCHED_LOAD_SCALE_FUZZ
;
3258 if ((skip_for_load
&& p
->prio
>= *this_best_prio
) ||
3259 !can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3260 p
= iterator
->next(iterator
->arg
);
3264 pull_task(busiest
, p
, this_rq
, this_cpu
);
3266 rem_load_move
-= p
->se
.load
.weight
;
3269 * We only want to steal up to the prescribed amount of weighted load.
3271 if (rem_load_move
> 0) {
3272 if (p
->prio
< *this_best_prio
)
3273 *this_best_prio
= p
->prio
;
3274 p
= iterator
->next(iterator
->arg
);
3279 * Right now, this is one of only two places pull_task() is called,
3280 * so we can safely collect pull_task() stats here rather than
3281 * inside pull_task().
3283 schedstat_add(sd
, lb_gained
[idle
], pulled
);
3286 *all_pinned
= pinned
;
3288 return max_load_move
- rem_load_move
;
3292 * move_tasks tries to move up to max_load_move weighted load from busiest to
3293 * this_rq, as part of a balancing operation within domain "sd".
3294 * Returns 1 if successful and 0 otherwise.
3296 * Called with both runqueues locked.
3298 static int move_tasks(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3299 unsigned long max_load_move
,
3300 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3303 const struct sched_class
*class = sched_class_highest
;
3304 unsigned long total_load_moved
= 0;
3305 int this_best_prio
= this_rq
->curr
->prio
;
3309 class->load_balance(this_rq
, this_cpu
, busiest
,
3310 max_load_move
- total_load_moved
,
3311 sd
, idle
, all_pinned
, &this_best_prio
);
3312 class = class->next
;
3313 } while (class && max_load_move
> total_load_moved
);
3315 return total_load_moved
> 0;
3319 iter_move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3320 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3321 struct rq_iterator
*iterator
)
3323 struct task_struct
*p
= iterator
->start(iterator
->arg
);
3327 if (can_migrate_task(p
, busiest
, this_cpu
, sd
, idle
, &pinned
)) {
3328 pull_task(busiest
, p
, this_rq
, this_cpu
);
3330 * Right now, this is only the second place pull_task()
3331 * is called, so we can safely collect pull_task()
3332 * stats here rather than inside pull_task().
3334 schedstat_inc(sd
, lb_gained
[idle
]);
3338 p
= iterator
->next(iterator
->arg
);
3345 * move_one_task tries to move exactly one task from busiest to this_rq, as
3346 * part of active balancing operations within "domain".
3347 * Returns 1 if successful and 0 otherwise.
3349 * Called with both runqueues locked.
3351 static int move_one_task(struct rq
*this_rq
, int this_cpu
, struct rq
*busiest
,
3352 struct sched_domain
*sd
, enum cpu_idle_type idle
)
3354 const struct sched_class
*class;
3356 for (class = sched_class_highest
; class; class = class->next
)
3357 if (class->move_one_task(this_rq
, this_cpu
, busiest
, sd
, idle
))
3364 * find_busiest_group finds and returns the busiest CPU group within the
3365 * domain. It calculates and returns the amount of weighted load which
3366 * should be moved to restore balance via the imbalance parameter.
3368 static struct sched_group
*
3369 find_busiest_group(struct sched_domain
*sd
, int this_cpu
,
3370 unsigned long *imbalance
, enum cpu_idle_type idle
,
3371 int *sd_idle
, const cpumask_t
*cpus
, int *balance
)
3373 struct sched_group
*busiest
= NULL
, *this = NULL
, *group
= sd
->groups
;
3374 unsigned long max_load
, avg_load
, total_load
, this_load
, total_pwr
;
3375 unsigned long max_pull
;
3376 unsigned long busiest_load_per_task
, busiest_nr_running
;
3377 unsigned long this_load_per_task
, this_nr_running
;
3378 int load_idx
, group_imb
= 0;
3379 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3380 int power_savings_balance
= 1;
3381 unsigned long leader_nr_running
= 0, min_load_per_task
= 0;
3382 unsigned long min_nr_running
= ULONG_MAX
;
3383 struct sched_group
*group_min
= NULL
, *group_leader
= NULL
;
3386 max_load
= this_load
= total_load
= total_pwr
= 0;
3387 busiest_load_per_task
= busiest_nr_running
= 0;
3388 this_load_per_task
= this_nr_running
= 0;
3389 if (idle
== CPU_NOT_IDLE
)
3390 load_idx
= sd
->busy_idx
;
3391 else if (idle
== CPU_NEWLY_IDLE
)
3392 load_idx
= sd
->newidle_idx
;
3394 load_idx
= sd
->idle_idx
;
3397 unsigned long load
, group_capacity
, max_cpu_load
, min_cpu_load
;
3400 int __group_imb
= 0;
3401 unsigned int balance_cpu
= -1, first_idle_cpu
= 0;
3402 unsigned long sum_nr_running
, sum_weighted_load
;
3404 local_group
= cpu_isset(this_cpu
, group
->cpumask
);
3407 balance_cpu
= first_cpu(group
->cpumask
);
3409 /* Tally up the load of all CPUs in the group */
3410 sum_weighted_load
= sum_nr_running
= avg_load
= 0;
3412 min_cpu_load
= ~0UL;
3414 for_each_cpu_mask(i
, group
->cpumask
) {
3417 if (!cpu_isset(i
, *cpus
))
3422 if (*sd_idle
&& rq
->nr_running
)
3425 /* Bias balancing toward cpus of our domain */
3427 if (idle_cpu(i
) && !first_idle_cpu
) {
3432 load
= target_load(i
, load_idx
);
3434 load
= source_load(i
, load_idx
);
3435 if (load
> max_cpu_load
)
3436 max_cpu_load
= load
;
3437 if (min_cpu_load
> load
)
3438 min_cpu_load
= load
;
3442 sum_nr_running
+= rq
->nr_running
;
3443 sum_weighted_load
+= weighted_cpuload(i
);
3447 * First idle cpu or the first cpu(busiest) in this sched group
3448 * is eligible for doing load balancing at this and above
3449 * domains. In the newly idle case, we will allow all the cpu's
3450 * to do the newly idle load balance.
3452 if (idle
!= CPU_NEWLY_IDLE
&& local_group
&&
3453 balance_cpu
!= this_cpu
&& balance
) {
3458 total_load
+= avg_load
;
3459 total_pwr
+= group
->__cpu_power
;
3461 /* Adjust by relative CPU power of the group */
3462 avg_load
= sg_div_cpu_power(group
,
3463 avg_load
* SCHED_LOAD_SCALE
);
3465 if ((max_cpu_load
- min_cpu_load
) > SCHED_LOAD_SCALE
)
3468 group_capacity
= group
->__cpu_power
/ SCHED_LOAD_SCALE
;
3471 this_load
= avg_load
;
3473 this_nr_running
= sum_nr_running
;
3474 this_load_per_task
= sum_weighted_load
;
3475 } else if (avg_load
> max_load
&&
3476 (sum_nr_running
> group_capacity
|| __group_imb
)) {
3477 max_load
= avg_load
;
3479 busiest_nr_running
= sum_nr_running
;
3480 busiest_load_per_task
= sum_weighted_load
;
3481 group_imb
= __group_imb
;
3484 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3486 * Busy processors will not participate in power savings
3489 if (idle
== CPU_NOT_IDLE
||
3490 !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3494 * If the local group is idle or completely loaded
3495 * no need to do power savings balance at this domain
3497 if (local_group
&& (this_nr_running
>= group_capacity
||
3499 power_savings_balance
= 0;
3502 * If a group is already running at full capacity or idle,
3503 * don't include that group in power savings calculations
3505 if (!power_savings_balance
|| sum_nr_running
>= group_capacity
3510 * Calculate the group which has the least non-idle load.
3511 * This is the group from where we need to pick up the load
3514 if ((sum_nr_running
< min_nr_running
) ||
3515 (sum_nr_running
== min_nr_running
&&
3516 first_cpu(group
->cpumask
) <
3517 first_cpu(group_min
->cpumask
))) {
3519 min_nr_running
= sum_nr_running
;
3520 min_load_per_task
= sum_weighted_load
/
3525 * Calculate the group which is almost near its
3526 * capacity but still has some space to pick up some load
3527 * from other group and save more power
3529 if (sum_nr_running
<= group_capacity
- 1) {
3530 if (sum_nr_running
> leader_nr_running
||
3531 (sum_nr_running
== leader_nr_running
&&
3532 first_cpu(group
->cpumask
) >
3533 first_cpu(group_leader
->cpumask
))) {
3534 group_leader
= group
;
3535 leader_nr_running
= sum_nr_running
;
3540 group
= group
->next
;
3541 } while (group
!= sd
->groups
);
3543 if (!busiest
|| this_load
>= max_load
|| busiest_nr_running
== 0)
3546 avg_load
= (SCHED_LOAD_SCALE
* total_load
) / total_pwr
;
3548 if (this_load
>= avg_load
||
3549 100*max_load
<= sd
->imbalance_pct
*this_load
)
3552 busiest_load_per_task
/= busiest_nr_running
;
3554 busiest_load_per_task
= min(busiest_load_per_task
, avg_load
);
3557 * We're trying to get all the cpus to the average_load, so we don't
3558 * want to push ourselves above the average load, nor do we wish to
3559 * reduce the max loaded cpu below the average load, as either of these
3560 * actions would just result in more rebalancing later, and ping-pong
3561 * tasks around. Thus we look for the minimum possible imbalance.
3562 * Negative imbalances (*we* are more loaded than anyone else) will
3563 * be counted as no imbalance for these purposes -- we can't fix that
3564 * by pulling tasks to us. Be careful of negative numbers as they'll
3565 * appear as very large values with unsigned longs.
3567 if (max_load
<= busiest_load_per_task
)
3571 * In the presence of smp nice balancing, certain scenarios can have
3572 * max load less than avg load(as we skip the groups at or below
3573 * its cpu_power, while calculating max_load..)
3575 if (max_load
< avg_load
) {
3577 goto small_imbalance
;
3580 /* Don't want to pull so many tasks that a group would go idle */
3581 max_pull
= min(max_load
- avg_load
, max_load
- busiest_load_per_task
);
3583 /* How much load to actually move to equalise the imbalance */
3584 *imbalance
= min(max_pull
* busiest
->__cpu_power
,
3585 (avg_load
- this_load
) * this->__cpu_power
)
3589 * if *imbalance is less than the average load per runnable task
3590 * there is no gaurantee that any tasks will be moved so we'll have
3591 * a think about bumping its value to force at least one task to be
3594 if (*imbalance
< busiest_load_per_task
) {
3595 unsigned long tmp
, pwr_now
, pwr_move
;
3599 pwr_move
= pwr_now
= 0;
3601 if (this_nr_running
) {
3602 this_load_per_task
/= this_nr_running
;
3603 if (busiest_load_per_task
> this_load_per_task
)
3606 this_load_per_task
= SCHED_LOAD_SCALE
;
3608 if (max_load
- this_load
+ SCHED_LOAD_SCALE_FUZZ
>=
3609 busiest_load_per_task
* imbn
) {
3610 *imbalance
= busiest_load_per_task
;
3615 * OK, we don't have enough imbalance to justify moving tasks,
3616 * however we may be able to increase total CPU power used by
3620 pwr_now
+= busiest
->__cpu_power
*
3621 min(busiest_load_per_task
, max_load
);
3622 pwr_now
+= this->__cpu_power
*
3623 min(this_load_per_task
, this_load
);
3624 pwr_now
/= SCHED_LOAD_SCALE
;
3626 /* Amount of load we'd subtract */
3627 tmp
= sg_div_cpu_power(busiest
,
3628 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3630 pwr_move
+= busiest
->__cpu_power
*
3631 min(busiest_load_per_task
, max_load
- tmp
);
3633 /* Amount of load we'd add */
3634 if (max_load
* busiest
->__cpu_power
<
3635 busiest_load_per_task
* SCHED_LOAD_SCALE
)
3636 tmp
= sg_div_cpu_power(this,
3637 max_load
* busiest
->__cpu_power
);
3639 tmp
= sg_div_cpu_power(this,
3640 busiest_load_per_task
* SCHED_LOAD_SCALE
);
3641 pwr_move
+= this->__cpu_power
*
3642 min(this_load_per_task
, this_load
+ tmp
);
3643 pwr_move
/= SCHED_LOAD_SCALE
;
3645 /* Move if we gain throughput */
3646 if (pwr_move
> pwr_now
)
3647 *imbalance
= busiest_load_per_task
;
3653 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3654 if (idle
== CPU_NOT_IDLE
|| !(sd
->flags
& SD_POWERSAVINGS_BALANCE
))
3657 if (this == group_leader
&& group_leader
!= group_min
) {
3658 *imbalance
= min_load_per_task
;
3668 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3671 find_busiest_queue(struct sched_group
*group
, enum cpu_idle_type idle
,
3672 unsigned long imbalance
, const cpumask_t
*cpus
)
3674 struct rq
*busiest
= NULL
, *rq
;
3675 unsigned long max_load
= 0;
3678 for_each_cpu_mask(i
, group
->cpumask
) {
3681 if (!cpu_isset(i
, *cpus
))
3685 wl
= weighted_cpuload(i
);
3687 if (rq
->nr_running
== 1 && wl
> imbalance
)
3690 if (wl
> max_load
) {
3700 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3701 * so long as it is large enough.
3703 #define MAX_PINNED_INTERVAL 512
3706 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3707 * tasks if there is an imbalance.
3709 static int load_balance(int this_cpu
, struct rq
*this_rq
,
3710 struct sched_domain
*sd
, enum cpu_idle_type idle
,
3711 int *balance
, cpumask_t
*cpus
)
3713 int ld_moved
, all_pinned
= 0, active_balance
= 0, sd_idle
= 0;
3714 struct sched_group
*group
;
3715 unsigned long imbalance
;
3717 unsigned long flags
;
3718 int unlock_aggregate
;
3722 unlock_aggregate
= get_aggregate(sd
);
3725 * When power savings policy is enabled for the parent domain, idle
3726 * sibling can pick up load irrespective of busy siblings. In this case,
3727 * let the state of idle sibling percolate up as CPU_IDLE, instead of
3728 * portraying it as CPU_NOT_IDLE.
3730 if (idle
!= CPU_NOT_IDLE
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3731 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3734 schedstat_inc(sd
, lb_count
[idle
]);
3737 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, idle
, &sd_idle
,
3744 schedstat_inc(sd
, lb_nobusyg
[idle
]);
3748 busiest
= find_busiest_queue(group
, idle
, imbalance
, cpus
);
3750 schedstat_inc(sd
, lb_nobusyq
[idle
]);
3754 BUG_ON(busiest
== this_rq
);
3756 schedstat_add(sd
, lb_imbalance
[idle
], imbalance
);
3759 if (busiest
->nr_running
> 1) {
3761 * Attempt to move tasks. If find_busiest_group has found
3762 * an imbalance but busiest->nr_running <= 1, the group is
3763 * still unbalanced. ld_moved simply stays zero, so it is
3764 * correctly treated as an imbalance.
3766 local_irq_save(flags
);
3767 double_rq_lock(this_rq
, busiest
);
3768 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3769 imbalance
, sd
, idle
, &all_pinned
);
3770 double_rq_unlock(this_rq
, busiest
);
3771 local_irq_restore(flags
);
3774 * some other cpu did the load balance for us.
3776 if (ld_moved
&& this_cpu
!= smp_processor_id())
3777 resched_cpu(this_cpu
);
3779 /* All tasks on this runqueue were pinned by CPU affinity */
3780 if (unlikely(all_pinned
)) {
3781 cpu_clear(cpu_of(busiest
), *cpus
);
3782 if (!cpus_empty(*cpus
))
3789 schedstat_inc(sd
, lb_failed
[idle
]);
3790 sd
->nr_balance_failed
++;
3792 if (unlikely(sd
->nr_balance_failed
> sd
->cache_nice_tries
+2)) {
3794 spin_lock_irqsave(&busiest
->lock
, flags
);
3796 /* don't kick the migration_thread, if the curr
3797 * task on busiest cpu can't be moved to this_cpu
3799 if (!cpu_isset(this_cpu
, busiest
->curr
->cpus_allowed
)) {
3800 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3802 goto out_one_pinned
;
3805 if (!busiest
->active_balance
) {
3806 busiest
->active_balance
= 1;
3807 busiest
->push_cpu
= this_cpu
;
3810 spin_unlock_irqrestore(&busiest
->lock
, flags
);
3812 wake_up_process(busiest
->migration_thread
);
3815 * We've kicked active balancing, reset the failure
3818 sd
->nr_balance_failed
= sd
->cache_nice_tries
+1;
3821 sd
->nr_balance_failed
= 0;
3823 if (likely(!active_balance
)) {
3824 /* We were unbalanced, so reset the balancing interval */
3825 sd
->balance_interval
= sd
->min_interval
;
3828 * If we've begun active balancing, start to back off. This
3829 * case may not be covered by the all_pinned logic if there
3830 * is only 1 task on the busy runqueue (because we don't call
3833 if (sd
->balance_interval
< sd
->max_interval
)
3834 sd
->balance_interval
*= 2;
3837 if (!ld_moved
&& !sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3838 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3844 schedstat_inc(sd
, lb_balanced
[idle
]);
3846 sd
->nr_balance_failed
= 0;
3849 /* tune up the balancing interval */
3850 if ((all_pinned
&& sd
->balance_interval
< MAX_PINNED_INTERVAL
) ||
3851 (sd
->balance_interval
< sd
->max_interval
))
3852 sd
->balance_interval
*= 2;
3854 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3855 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3860 if (unlock_aggregate
)
3866 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3867 * tasks if there is an imbalance.
3869 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
3870 * this_rq is locked.
3873 load_balance_newidle(int this_cpu
, struct rq
*this_rq
, struct sched_domain
*sd
,
3876 struct sched_group
*group
;
3877 struct rq
*busiest
= NULL
;
3878 unsigned long imbalance
;
3886 * When power savings policy is enabled for the parent domain, idle
3887 * sibling can pick up load irrespective of busy siblings. In this case,
3888 * let the state of idle sibling percolate up as IDLE, instead of
3889 * portraying it as CPU_NOT_IDLE.
3891 if (sd
->flags
& SD_SHARE_CPUPOWER
&&
3892 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3895 schedstat_inc(sd
, lb_count
[CPU_NEWLY_IDLE
]);
3897 group
= find_busiest_group(sd
, this_cpu
, &imbalance
, CPU_NEWLY_IDLE
,
3898 &sd_idle
, cpus
, NULL
);
3900 schedstat_inc(sd
, lb_nobusyg
[CPU_NEWLY_IDLE
]);
3904 busiest
= find_busiest_queue(group
, CPU_NEWLY_IDLE
, imbalance
, cpus
);
3906 schedstat_inc(sd
, lb_nobusyq
[CPU_NEWLY_IDLE
]);
3910 BUG_ON(busiest
== this_rq
);
3912 schedstat_add(sd
, lb_imbalance
[CPU_NEWLY_IDLE
], imbalance
);
3915 if (busiest
->nr_running
> 1) {
3916 /* Attempt to move tasks */
3917 double_lock_balance(this_rq
, busiest
);
3918 /* this_rq->clock is already updated */
3919 update_rq_clock(busiest
);
3920 ld_moved
= move_tasks(this_rq
, this_cpu
, busiest
,
3921 imbalance
, sd
, CPU_NEWLY_IDLE
,
3923 spin_unlock(&busiest
->lock
);
3925 if (unlikely(all_pinned
)) {
3926 cpu_clear(cpu_of(busiest
), *cpus
);
3927 if (!cpus_empty(*cpus
))
3933 schedstat_inc(sd
, lb_failed
[CPU_NEWLY_IDLE
]);
3934 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3935 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3938 sd
->nr_balance_failed
= 0;
3943 schedstat_inc(sd
, lb_balanced
[CPU_NEWLY_IDLE
]);
3944 if (!sd_idle
&& sd
->flags
& SD_SHARE_CPUPOWER
&&
3945 !test_sd_parent(sd
, SD_POWERSAVINGS_BALANCE
))
3947 sd
->nr_balance_failed
= 0;
3953 * idle_balance is called by schedule() if this_cpu is about to become
3954 * idle. Attempts to pull tasks from other CPUs.
3956 static void idle_balance(int this_cpu
, struct rq
*this_rq
)
3958 struct sched_domain
*sd
;
3959 int pulled_task
= -1;
3960 unsigned long next_balance
= jiffies
+ HZ
;
3963 for_each_domain(this_cpu
, sd
) {
3964 unsigned long interval
;
3966 if (!(sd
->flags
& SD_LOAD_BALANCE
))
3969 if (sd
->flags
& SD_BALANCE_NEWIDLE
)
3970 /* If we've pulled tasks over stop searching: */
3971 pulled_task
= load_balance_newidle(this_cpu
, this_rq
,
3974 interval
= msecs_to_jiffies(sd
->balance_interval
);
3975 if (time_after(next_balance
, sd
->last_balance
+ interval
))
3976 next_balance
= sd
->last_balance
+ interval
;
3980 if (pulled_task
|| time_after(jiffies
, this_rq
->next_balance
)) {
3982 * We are going idle. next_balance may be set based on
3983 * a busy processor. So reset next_balance.
3985 this_rq
->next_balance
= next_balance
;
3990 * active_load_balance is run by migration threads. It pushes running tasks
3991 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3992 * running on each physical CPU where possible, and avoids physical /
3993 * logical imbalances.
3995 * Called with busiest_rq locked.
3997 static void active_load_balance(struct rq
*busiest_rq
, int busiest_cpu
)
3999 int target_cpu
= busiest_rq
->push_cpu
;
4000 struct sched_domain
*sd
;
4001 struct rq
*target_rq
;
4003 /* Is there any task to move? */
4004 if (busiest_rq
->nr_running
<= 1)
4007 target_rq
= cpu_rq(target_cpu
);
4010 * This condition is "impossible", if it occurs
4011 * we need to fix it. Originally reported by
4012 * Bjorn Helgaas on a 128-cpu setup.
4014 BUG_ON(busiest_rq
== target_rq
);
4016 /* move a task from busiest_rq to target_rq */
4017 double_lock_balance(busiest_rq
, target_rq
);
4018 update_rq_clock(busiest_rq
);
4019 update_rq_clock(target_rq
);
4021 /* Search for an sd spanning us and the target CPU. */
4022 for_each_domain(target_cpu
, sd
) {
4023 if ((sd
->flags
& SD_LOAD_BALANCE
) &&
4024 cpu_isset(busiest_cpu
, sd
->span
))
4029 schedstat_inc(sd
, alb_count
);
4031 if (move_one_task(target_rq
, target_cpu
, busiest_rq
,
4033 schedstat_inc(sd
, alb_pushed
);
4035 schedstat_inc(sd
, alb_failed
);
4037 spin_unlock(&target_rq
->lock
);
4042 atomic_t load_balancer
;
4044 } nohz ____cacheline_aligned
= {
4045 .load_balancer
= ATOMIC_INIT(-1),
4046 .cpu_mask
= CPU_MASK_NONE
,
4050 * This routine will try to nominate the ilb (idle load balancing)
4051 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
4052 * load balancing on behalf of all those cpus. If all the cpus in the system
4053 * go into this tickless mode, then there will be no ilb owner (as there is
4054 * no need for one) and all the cpus will sleep till the next wakeup event
4057 * For the ilb owner, tick is not stopped. And this tick will be used
4058 * for idle load balancing. ilb owner will still be part of
4061 * While stopping the tick, this cpu will become the ilb owner if there
4062 * is no other owner. And will be the owner till that cpu becomes busy
4063 * or if all cpus in the system stop their ticks at which point
4064 * there is no need for ilb owner.
4066 * When the ilb owner becomes busy, it nominates another owner, during the
4067 * next busy scheduler_tick()
4069 int select_nohz_load_balancer(int stop_tick
)
4071 int cpu
= smp_processor_id();
4074 cpu_set(cpu
, nohz
.cpu_mask
);
4075 cpu_rq(cpu
)->in_nohz_recently
= 1;
4078 * If we are going offline and still the leader, give up!
4080 if (cpu_is_offline(cpu
) &&
4081 atomic_read(&nohz
.load_balancer
) == cpu
) {
4082 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4087 /* time for ilb owner also to sleep */
4088 if (cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4089 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4090 atomic_set(&nohz
.load_balancer
, -1);
4094 if (atomic_read(&nohz
.load_balancer
) == -1) {
4095 /* make me the ilb owner */
4096 if (atomic_cmpxchg(&nohz
.load_balancer
, -1, cpu
) == -1)
4098 } else if (atomic_read(&nohz
.load_balancer
) == cpu
)
4101 if (!cpu_isset(cpu
, nohz
.cpu_mask
))
4104 cpu_clear(cpu
, nohz
.cpu_mask
);
4106 if (atomic_read(&nohz
.load_balancer
) == cpu
)
4107 if (atomic_cmpxchg(&nohz
.load_balancer
, cpu
, -1) != cpu
)
4114 static DEFINE_SPINLOCK(balancing
);
4117 * It checks each scheduling domain to see if it is due to be balanced,
4118 * and initiates a balancing operation if so.
4120 * Balancing parameters are set up in arch_init_sched_domains.
4122 static void rebalance_domains(int cpu
, enum cpu_idle_type idle
)
4125 struct rq
*rq
= cpu_rq(cpu
);
4126 unsigned long interval
;
4127 struct sched_domain
*sd
;
4128 /* Earliest time when we have to do rebalance again */
4129 unsigned long next_balance
= jiffies
+ 60*HZ
;
4130 int update_next_balance
= 0;
4133 for_each_domain(cpu
, sd
) {
4134 if (!(sd
->flags
& SD_LOAD_BALANCE
))
4137 interval
= sd
->balance_interval
;
4138 if (idle
!= CPU_IDLE
)
4139 interval
*= sd
->busy_factor
;
4141 /* scale ms to jiffies */
4142 interval
= msecs_to_jiffies(interval
);
4143 if (unlikely(!interval
))
4145 if (interval
> HZ
*NR_CPUS
/10)
4146 interval
= HZ
*NR_CPUS
/10;
4149 if (sd
->flags
& SD_SERIALIZE
) {
4150 if (!spin_trylock(&balancing
))
4154 if (time_after_eq(jiffies
, sd
->last_balance
+ interval
)) {
4155 if (load_balance(cpu
, rq
, sd
, idle
, &balance
, &tmp
)) {
4157 * We've pulled tasks over so either we're no
4158 * longer idle, or one of our SMT siblings is
4161 idle
= CPU_NOT_IDLE
;
4163 sd
->last_balance
= jiffies
;
4165 if (sd
->flags
& SD_SERIALIZE
)
4166 spin_unlock(&balancing
);
4168 if (time_after(next_balance
, sd
->last_balance
+ interval
)) {
4169 next_balance
= sd
->last_balance
+ interval
;
4170 update_next_balance
= 1;
4174 * Stop the load balance at this level. There is another
4175 * CPU in our sched group which is doing load balancing more
4183 * next_balance will be updated only when there is a need.
4184 * When the cpu is attached to null domain for ex, it will not be
4187 if (likely(update_next_balance
))
4188 rq
->next_balance
= next_balance
;
4192 * run_rebalance_domains is triggered when needed from the scheduler tick.
4193 * In CONFIG_NO_HZ case, the idle load balance owner will do the
4194 * rebalancing for all the cpus for whom scheduler ticks are stopped.
4196 static void run_rebalance_domains(struct softirq_action
*h
)
4198 int this_cpu
= smp_processor_id();
4199 struct rq
*this_rq
= cpu_rq(this_cpu
);
4200 enum cpu_idle_type idle
= this_rq
->idle_at_tick
?
4201 CPU_IDLE
: CPU_NOT_IDLE
;
4203 rebalance_domains(this_cpu
, idle
);
4207 * If this cpu is the owner for idle load balancing, then do the
4208 * balancing on behalf of the other idle cpus whose ticks are
4211 if (this_rq
->idle_at_tick
&&
4212 atomic_read(&nohz
.load_balancer
) == this_cpu
) {
4213 cpumask_t cpus
= nohz
.cpu_mask
;
4217 cpu_clear(this_cpu
, cpus
);
4218 for_each_cpu_mask(balance_cpu
, cpus
) {
4220 * If this cpu gets work to do, stop the load balancing
4221 * work being done for other cpus. Next load
4222 * balancing owner will pick it up.
4227 rebalance_domains(balance_cpu
, CPU_IDLE
);
4229 rq
= cpu_rq(balance_cpu
);
4230 if (time_after(this_rq
->next_balance
, rq
->next_balance
))
4231 this_rq
->next_balance
= rq
->next_balance
;
4238 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
4240 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
4241 * idle load balancing owner or decide to stop the periodic load balancing,
4242 * if the whole system is idle.
4244 static inline void trigger_load_balance(struct rq
*rq
, int cpu
)
4248 * If we were in the nohz mode recently and busy at the current
4249 * scheduler tick, then check if we need to nominate new idle
4252 if (rq
->in_nohz_recently
&& !rq
->idle_at_tick
) {
4253 rq
->in_nohz_recently
= 0;
4255 if (atomic_read(&nohz
.load_balancer
) == cpu
) {
4256 cpu_clear(cpu
, nohz
.cpu_mask
);
4257 atomic_set(&nohz
.load_balancer
, -1);
4260 if (atomic_read(&nohz
.load_balancer
) == -1) {
4262 * simple selection for now: Nominate the
4263 * first cpu in the nohz list to be the next
4266 * TBD: Traverse the sched domains and nominate
4267 * the nearest cpu in the nohz.cpu_mask.
4269 int ilb
= first_cpu(nohz
.cpu_mask
);
4271 if (ilb
< nr_cpu_ids
)
4277 * If this cpu is idle and doing idle load balancing for all the
4278 * cpus with ticks stopped, is it time for that to stop?
4280 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) == cpu
&&
4281 cpus_weight(nohz
.cpu_mask
) == num_online_cpus()) {
4287 * If this cpu is idle and the idle load balancing is done by
4288 * someone else, then no need raise the SCHED_SOFTIRQ
4290 if (rq
->idle_at_tick
&& atomic_read(&nohz
.load_balancer
) != cpu
&&
4291 cpu_isset(cpu
, nohz
.cpu_mask
))
4294 if (time_after_eq(jiffies
, rq
->next_balance
))
4295 raise_softirq(SCHED_SOFTIRQ
);
4298 #else /* CONFIG_SMP */
4301 * on UP we do not need to balance between CPUs:
4303 static inline void idle_balance(int cpu
, struct rq
*rq
)
4309 DEFINE_PER_CPU(struct kernel_stat
, kstat
);
4311 EXPORT_PER_CPU_SYMBOL(kstat
);
4314 * Return p->sum_exec_runtime plus any more ns on the sched_clock
4315 * that have not yet been banked in case the task is currently running.
4317 unsigned long long task_sched_runtime(struct task_struct
*p
)
4319 unsigned long flags
;
4323 rq
= task_rq_lock(p
, &flags
);
4324 ns
= p
->se
.sum_exec_runtime
;
4325 if (task_current(rq
, p
)) {
4326 update_rq_clock(rq
);
4327 delta_exec
= rq
->clock
- p
->se
.exec_start
;
4328 if ((s64
)delta_exec
> 0)
4331 task_rq_unlock(rq
, &flags
);
4337 * Account user cpu time to a process.
4338 * @p: the process that the cpu time gets accounted to
4339 * @cputime: the cpu time spent in user space since the last update
4341 void account_user_time(struct task_struct
*p
, cputime_t cputime
)
4343 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4346 p
->utime
= cputime_add(p
->utime
, cputime
);
4348 /* Add user time to cpustat. */
4349 tmp
= cputime_to_cputime64(cputime
);
4350 if (TASK_NICE(p
) > 0)
4351 cpustat
->nice
= cputime64_add(cpustat
->nice
, tmp
);
4353 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4357 * Account guest cpu time to a process.
4358 * @p: the process that the cpu time gets accounted to
4359 * @cputime: the cpu time spent in virtual machine since the last update
4361 static void account_guest_time(struct task_struct
*p
, cputime_t cputime
)
4364 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4366 tmp
= cputime_to_cputime64(cputime
);
4368 p
->utime
= cputime_add(p
->utime
, cputime
);
4369 p
->gtime
= cputime_add(p
->gtime
, cputime
);
4371 cpustat
->user
= cputime64_add(cpustat
->user
, tmp
);
4372 cpustat
->guest
= cputime64_add(cpustat
->guest
, tmp
);
4376 * Account scaled user cpu time to a process.
4377 * @p: the process that the cpu time gets accounted to
4378 * @cputime: the cpu time spent in user space since the last update
4380 void account_user_time_scaled(struct task_struct
*p
, cputime_t cputime
)
4382 p
->utimescaled
= cputime_add(p
->utimescaled
, cputime
);
4386 * Account system cpu time to a process.
4387 * @p: the process that the cpu time gets accounted to
4388 * @hardirq_offset: the offset to subtract from hardirq_count()
4389 * @cputime: the cpu time spent in kernel space since the last update
4391 void account_system_time(struct task_struct
*p
, int hardirq_offset
,
4394 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4395 struct rq
*rq
= this_rq();
4398 if ((p
->flags
& PF_VCPU
) && (irq_count() - hardirq_offset
== 0)) {
4399 account_guest_time(p
, cputime
);
4403 p
->stime
= cputime_add(p
->stime
, cputime
);
4405 /* Add system time to cpustat. */
4406 tmp
= cputime_to_cputime64(cputime
);
4407 if (hardirq_count() - hardirq_offset
)
4408 cpustat
->irq
= cputime64_add(cpustat
->irq
, tmp
);
4409 else if (softirq_count())
4410 cpustat
->softirq
= cputime64_add(cpustat
->softirq
, tmp
);
4411 else if (p
!= rq
->idle
)
4412 cpustat
->system
= cputime64_add(cpustat
->system
, tmp
);
4413 else if (atomic_read(&rq
->nr_iowait
) > 0)
4414 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
4416 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
4417 /* Account for system time used */
4418 acct_update_integrals(p
);
4422 * Account scaled system cpu time to a process.
4423 * @p: the process that the cpu time gets accounted to
4424 * @hardirq_offset: the offset to subtract from hardirq_count()
4425 * @cputime: the cpu time spent in kernel space since the last update
4427 void account_system_time_scaled(struct task_struct
*p
, cputime_t cputime
)
4429 p
->stimescaled
= cputime_add(p
->stimescaled
, cputime
);
4433 * Account for involuntary wait time.
4434 * @p: the process from which the cpu time has been stolen
4435 * @steal: the cpu time spent in involuntary wait
4437 void account_steal_time(struct task_struct
*p
, cputime_t steal
)
4439 struct cpu_usage_stat
*cpustat
= &kstat_this_cpu
.cpustat
;
4440 cputime64_t tmp
= cputime_to_cputime64(steal
);
4441 struct rq
*rq
= this_rq();
4443 if (p
== rq
->idle
) {
4444 p
->stime
= cputime_add(p
->stime
, steal
);
4445 if (atomic_read(&rq
->nr_iowait
) > 0)
4446 cpustat
->iowait
= cputime64_add(cpustat
->iowait
, tmp
);
4448 cpustat
->idle
= cputime64_add(cpustat
->idle
, tmp
);
4450 cpustat
->steal
= cputime64_add(cpustat
->steal
, tmp
);
4454 * This function gets called by the timer code, with HZ frequency.
4455 * We call it with interrupts disabled.
4457 * It also gets called by the fork code, when changing the parent's
4460 void scheduler_tick(void)
4462 int cpu
= smp_processor_id();
4463 struct rq
*rq
= cpu_rq(cpu
);
4464 struct task_struct
*curr
= rq
->curr
;
4465 u64 next_tick
= rq
->tick_timestamp
+ TICK_NSEC
;
4467 spin_lock(&rq
->lock
);
4468 __update_rq_clock(rq
);
4470 * Let rq->clock advance by at least TICK_NSEC:
4472 if (unlikely(rq
->clock
< next_tick
)) {
4473 rq
->clock
= next_tick
;
4474 rq
->clock_underflows
++;
4476 rq
->tick_timestamp
= rq
->clock
;
4477 update_last_tick_seen(rq
);
4478 update_cpu_load(rq
);
4479 curr
->sched_class
->task_tick(rq
, curr
, 0);
4480 spin_unlock(&rq
->lock
);
4483 rq
->idle_at_tick
= idle_cpu(cpu
);
4484 trigger_load_balance(rq
, cpu
);
4488 #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
4490 void __kprobes
add_preempt_count(int val
)
4495 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4497 preempt_count() += val
;
4499 * Spinlock count overflowing soon?
4501 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK
) >=
4504 EXPORT_SYMBOL(add_preempt_count
);
4506 void __kprobes
sub_preempt_count(int val
)
4511 if (DEBUG_LOCKS_WARN_ON(val
> preempt_count()))
4514 * Is the spinlock portion underflowing?
4516 if (DEBUG_LOCKS_WARN_ON((val
< PREEMPT_MASK
) &&
4517 !(preempt_count() & PREEMPT_MASK
)))
4520 preempt_count() -= val
;
4522 EXPORT_SYMBOL(sub_preempt_count
);
4527 * Print scheduling while atomic bug:
4529 static noinline
void __schedule_bug(struct task_struct
*prev
)
4531 struct pt_regs
*regs
= get_irq_regs();
4533 printk(KERN_ERR
"BUG: scheduling while atomic: %s/%d/0x%08x\n",
4534 prev
->comm
, prev
->pid
, preempt_count());
4536 debug_show_held_locks(prev
);
4537 if (irqs_disabled())
4538 print_irqtrace_events(prev
);
4547 * Various schedule()-time debugging checks and statistics:
4549 static inline void schedule_debug(struct task_struct
*prev
)
4552 * Test if we are atomic. Since do_exit() needs to call into
4553 * schedule() atomically, we ignore that path for now.
4554 * Otherwise, whine if we are scheduling when we should not be.
4556 if (unlikely(in_atomic_preempt_off()) && unlikely(!prev
->exit_state
))
4557 __schedule_bug(prev
);
4559 profile_hit(SCHED_PROFILING
, __builtin_return_address(0));
4561 schedstat_inc(this_rq(), sched_count
);
4562 #ifdef CONFIG_SCHEDSTATS
4563 if (unlikely(prev
->lock_depth
>= 0)) {
4564 schedstat_inc(this_rq(), bkl_count
);
4565 schedstat_inc(prev
, sched_info
.bkl_count
);
4571 * Pick up the highest-prio task:
4573 static inline struct task_struct
*
4574 pick_next_task(struct rq
*rq
, struct task_struct
*prev
)
4576 const struct sched_class
*class;
4577 struct task_struct
*p
;
4580 * Optimization: we know that if all tasks are in
4581 * the fair class we can call that function directly:
4583 if (likely(rq
->nr_running
== rq
->cfs
.nr_running
)) {
4584 p
= fair_sched_class
.pick_next_task(rq
);
4589 class = sched_class_highest
;
4591 p
= class->pick_next_task(rq
);
4595 * Will never be NULL as the idle class always
4596 * returns a non-NULL p:
4598 class = class->next
;
4603 * schedule() is the main scheduler function.
4605 asmlinkage
void __sched
schedule(void)
4607 struct task_struct
*prev
, *next
;
4608 unsigned long *switch_count
;
4614 cpu
= smp_processor_id();
4618 switch_count
= &prev
->nivcsw
;
4620 release_kernel_lock(prev
);
4621 need_resched_nonpreemptible
:
4623 schedule_debug(prev
);
4628 * Do the rq-clock update outside the rq lock:
4630 local_irq_disable();
4631 __update_rq_clock(rq
);
4632 spin_lock(&rq
->lock
);
4633 clear_tsk_need_resched(prev
);
4635 if (prev
->state
&& !(preempt_count() & PREEMPT_ACTIVE
)) {
4636 if (unlikely((prev
->state
& TASK_INTERRUPTIBLE
) &&
4637 signal_pending(prev
))) {
4638 prev
->state
= TASK_RUNNING
;
4640 deactivate_task(rq
, prev
, 1);
4642 switch_count
= &prev
->nvcsw
;
4646 if (prev
->sched_class
->pre_schedule
)
4647 prev
->sched_class
->pre_schedule(rq
, prev
);
4650 if (unlikely(!rq
->nr_running
))
4651 idle_balance(cpu
, rq
);
4653 prev
->sched_class
->put_prev_task(rq
, prev
);
4654 next
= pick_next_task(rq
, prev
);
4656 if (likely(prev
!= next
)) {
4657 sched_info_switch(prev
, next
);
4663 context_switch(rq
, prev
, next
); /* unlocks the rq */
4665 * the context switch might have flipped the stack from under
4666 * us, hence refresh the local variables.
4668 cpu
= smp_processor_id();
4671 spin_unlock_irq(&rq
->lock
);
4675 if (unlikely(reacquire_kernel_lock(current
) < 0))
4676 goto need_resched_nonpreemptible
;
4678 preempt_enable_no_resched();
4679 if (unlikely(test_thread_flag(TIF_NEED_RESCHED
)))
4682 EXPORT_SYMBOL(schedule
);
4684 #ifdef CONFIG_PREEMPT
4686 * this is the entry point to schedule() from in-kernel preemption
4687 * off of preempt_enable. Kernel preemptions off return from interrupt
4688 * occur there and call schedule directly.
4690 asmlinkage
void __sched
preempt_schedule(void)
4692 struct thread_info
*ti
= current_thread_info();
4693 struct task_struct
*task
= current
;
4694 int saved_lock_depth
;
4697 * If there is a non-zero preempt_count or interrupts are disabled,
4698 * we do not want to preempt the current task. Just return..
4700 if (likely(ti
->preempt_count
|| irqs_disabled()))
4704 add_preempt_count(PREEMPT_ACTIVE
);
4707 * We keep the big kernel semaphore locked, but we
4708 * clear ->lock_depth so that schedule() doesnt
4709 * auto-release the semaphore:
4711 saved_lock_depth
= task
->lock_depth
;
4712 task
->lock_depth
= -1;
4714 task
->lock_depth
= saved_lock_depth
;
4715 sub_preempt_count(PREEMPT_ACTIVE
);
4718 * Check again in case we missed a preemption opportunity
4719 * between schedule and now.
4722 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4724 EXPORT_SYMBOL(preempt_schedule
);
4727 * this is the entry point to schedule() from kernel preemption
4728 * off of irq context.
4729 * Note, that this is called and return with irqs disabled. This will
4730 * protect us against recursive calling from irq.
4732 asmlinkage
void __sched
preempt_schedule_irq(void)
4734 struct thread_info
*ti
= current_thread_info();
4735 struct task_struct
*task
= current
;
4736 int saved_lock_depth
;
4738 /* Catch callers which need to be fixed */
4739 BUG_ON(ti
->preempt_count
|| !irqs_disabled());
4742 add_preempt_count(PREEMPT_ACTIVE
);
4745 * We keep the big kernel semaphore locked, but we
4746 * clear ->lock_depth so that schedule() doesnt
4747 * auto-release the semaphore:
4749 saved_lock_depth
= task
->lock_depth
;
4750 task
->lock_depth
= -1;
4753 local_irq_disable();
4754 task
->lock_depth
= saved_lock_depth
;
4755 sub_preempt_count(PREEMPT_ACTIVE
);
4758 * Check again in case we missed a preemption opportunity
4759 * between schedule and now.
4762 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED
)));
4765 #endif /* CONFIG_PREEMPT */
4767 int default_wake_function(wait_queue_t
*curr
, unsigned mode
, int sync
,
4770 return try_to_wake_up(curr
->private, mode
, sync
);
4772 EXPORT_SYMBOL(default_wake_function
);
4775 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4776 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
4777 * number) then we wake all the non-exclusive tasks and one exclusive task.
4779 * There are circumstances in which we can try to wake a task which has already
4780 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
4781 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4783 static void __wake_up_common(wait_queue_head_t
*q
, unsigned int mode
,
4784 int nr_exclusive
, int sync
, void *key
)
4786 wait_queue_t
*curr
, *next
;
4788 list_for_each_entry_safe(curr
, next
, &q
->task_list
, task_list
) {
4789 unsigned flags
= curr
->flags
;
4791 if (curr
->func(curr
, mode
, sync
, key
) &&
4792 (flags
& WQ_FLAG_EXCLUSIVE
) && !--nr_exclusive
)
4798 * __wake_up - wake up threads blocked on a waitqueue.
4800 * @mode: which threads
4801 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4802 * @key: is directly passed to the wakeup function
4804 void __wake_up(wait_queue_head_t
*q
, unsigned int mode
,
4805 int nr_exclusive
, void *key
)
4807 unsigned long flags
;
4809 spin_lock_irqsave(&q
->lock
, flags
);
4810 __wake_up_common(q
, mode
, nr_exclusive
, 0, key
);
4811 spin_unlock_irqrestore(&q
->lock
, flags
);
4813 EXPORT_SYMBOL(__wake_up
);
4816 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4818 void __wake_up_locked(wait_queue_head_t
*q
, unsigned int mode
)
4820 __wake_up_common(q
, mode
, 1, 0, NULL
);
4824 * __wake_up_sync - wake up threads blocked on a waitqueue.
4826 * @mode: which threads
4827 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4829 * The sync wakeup differs that the waker knows that it will schedule
4830 * away soon, so while the target thread will be woken up, it will not
4831 * be migrated to another CPU - ie. the two threads are 'synchronized'
4832 * with each other. This can prevent needless bouncing between CPUs.
4834 * On UP it can prevent extra preemption.
4837 __wake_up_sync(wait_queue_head_t
*q
, unsigned int mode
, int nr_exclusive
)
4839 unsigned long flags
;
4845 if (unlikely(!nr_exclusive
))
4848 spin_lock_irqsave(&q
->lock
, flags
);
4849 __wake_up_common(q
, mode
, nr_exclusive
, sync
, NULL
);
4850 spin_unlock_irqrestore(&q
->lock
, flags
);
4852 EXPORT_SYMBOL_GPL(__wake_up_sync
); /* For internal use only */
4854 void complete(struct completion
*x
)
4856 unsigned long flags
;
4858 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4860 __wake_up_common(&x
->wait
, TASK_NORMAL
, 1, 0, NULL
);
4861 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4863 EXPORT_SYMBOL(complete
);
4865 void complete_all(struct completion
*x
)
4867 unsigned long flags
;
4869 spin_lock_irqsave(&x
->wait
.lock
, flags
);
4870 x
->done
+= UINT_MAX
/2;
4871 __wake_up_common(&x
->wait
, TASK_NORMAL
, 0, 0, NULL
);
4872 spin_unlock_irqrestore(&x
->wait
.lock
, flags
);
4874 EXPORT_SYMBOL(complete_all
);
4876 static inline long __sched
4877 do_wait_for_common(struct completion
*x
, long timeout
, int state
)
4880 DECLARE_WAITQUEUE(wait
, current
);
4882 wait
.flags
|= WQ_FLAG_EXCLUSIVE
;
4883 __add_wait_queue_tail(&x
->wait
, &wait
);
4885 if ((state
== TASK_INTERRUPTIBLE
&&
4886 signal_pending(current
)) ||
4887 (state
== TASK_KILLABLE
&&
4888 fatal_signal_pending(current
))) {
4889 __remove_wait_queue(&x
->wait
, &wait
);
4890 return -ERESTARTSYS
;
4892 __set_current_state(state
);
4893 spin_unlock_irq(&x
->wait
.lock
);
4894 timeout
= schedule_timeout(timeout
);
4895 spin_lock_irq(&x
->wait
.lock
);
4897 __remove_wait_queue(&x
->wait
, &wait
);
4901 __remove_wait_queue(&x
->wait
, &wait
);
4908 wait_for_common(struct completion
*x
, long timeout
, int state
)
4912 spin_lock_irq(&x
->wait
.lock
);
4913 timeout
= do_wait_for_common(x
, timeout
, state
);
4914 spin_unlock_irq(&x
->wait
.lock
);
4918 void __sched
wait_for_completion(struct completion
*x
)
4920 wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_UNINTERRUPTIBLE
);
4922 EXPORT_SYMBOL(wait_for_completion
);
4924 unsigned long __sched
4925 wait_for_completion_timeout(struct completion
*x
, unsigned long timeout
)
4927 return wait_for_common(x
, timeout
, TASK_UNINTERRUPTIBLE
);
4929 EXPORT_SYMBOL(wait_for_completion_timeout
);
4931 int __sched
wait_for_completion_interruptible(struct completion
*x
)
4933 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_INTERRUPTIBLE
);
4934 if (t
== -ERESTARTSYS
)
4938 EXPORT_SYMBOL(wait_for_completion_interruptible
);
4940 unsigned long __sched
4941 wait_for_completion_interruptible_timeout(struct completion
*x
,
4942 unsigned long timeout
)
4944 return wait_for_common(x
, timeout
, TASK_INTERRUPTIBLE
);
4946 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout
);
4948 int __sched
wait_for_completion_killable(struct completion
*x
)
4950 long t
= wait_for_common(x
, MAX_SCHEDULE_TIMEOUT
, TASK_KILLABLE
);
4951 if (t
== -ERESTARTSYS
)
4955 EXPORT_SYMBOL(wait_for_completion_killable
);
4958 sleep_on_common(wait_queue_head_t
*q
, int state
, long timeout
)
4960 unsigned long flags
;
4963 init_waitqueue_entry(&wait
, current
);
4965 __set_current_state(state
);
4967 spin_lock_irqsave(&q
->lock
, flags
);
4968 __add_wait_queue(q
, &wait
);
4969 spin_unlock(&q
->lock
);
4970 timeout
= schedule_timeout(timeout
);
4971 spin_lock_irq(&q
->lock
);
4972 __remove_wait_queue(q
, &wait
);
4973 spin_unlock_irqrestore(&q
->lock
, flags
);
4978 void __sched
interruptible_sleep_on(wait_queue_head_t
*q
)
4980 sleep_on_common(q
, TASK_INTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4982 EXPORT_SYMBOL(interruptible_sleep_on
);
4985 interruptible_sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4987 return sleep_on_common(q
, TASK_INTERRUPTIBLE
, timeout
);
4989 EXPORT_SYMBOL(interruptible_sleep_on_timeout
);
4991 void __sched
sleep_on(wait_queue_head_t
*q
)
4993 sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, MAX_SCHEDULE_TIMEOUT
);
4995 EXPORT_SYMBOL(sleep_on
);
4997 long __sched
sleep_on_timeout(wait_queue_head_t
*q
, long timeout
)
4999 return sleep_on_common(q
, TASK_UNINTERRUPTIBLE
, timeout
);
5001 EXPORT_SYMBOL(sleep_on_timeout
);
5003 #ifdef CONFIG_RT_MUTEXES
5006 * rt_mutex_setprio - set the current priority of a task
5008 * @prio: prio value (kernel-internal form)
5010 * This function changes the 'effective' priority of a task. It does
5011 * not touch ->normal_prio like __setscheduler().
5013 * Used by the rt_mutex code to implement priority inheritance logic.
5015 void rt_mutex_setprio(struct task_struct
*p
, int prio
)
5017 unsigned long flags
;
5018 int oldprio
, on_rq
, running
;
5020 const struct sched_class
*prev_class
= p
->sched_class
;
5022 BUG_ON(prio
< 0 || prio
> MAX_PRIO
);
5024 rq
= task_rq_lock(p
, &flags
);
5025 update_rq_clock(rq
);
5028 on_rq
= p
->se
.on_rq
;
5029 running
= task_current(rq
, p
);
5031 dequeue_task(rq
, p
, 0);
5033 p
->sched_class
->put_prev_task(rq
, p
);
5036 p
->sched_class
= &rt_sched_class
;
5038 p
->sched_class
= &fair_sched_class
;
5043 p
->sched_class
->set_curr_task(rq
);
5045 enqueue_task(rq
, p
, 0);
5047 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5049 task_rq_unlock(rq
, &flags
);
5054 void set_user_nice(struct task_struct
*p
, long nice
)
5056 int old_prio
, delta
, on_rq
;
5057 unsigned long flags
;
5060 if (TASK_NICE(p
) == nice
|| nice
< -20 || nice
> 19)
5063 * We have to be careful, if called from sys_setpriority(),
5064 * the task might be in the middle of scheduling on another CPU.
5066 rq
= task_rq_lock(p
, &flags
);
5067 update_rq_clock(rq
);
5069 * The RT priorities are set via sched_setscheduler(), but we still
5070 * allow the 'normal' nice value to be set - but as expected
5071 * it wont have any effect on scheduling until the task is
5072 * SCHED_FIFO/SCHED_RR:
5074 if (task_has_rt_policy(p
)) {
5075 p
->static_prio
= NICE_TO_PRIO(nice
);
5078 on_rq
= p
->se
.on_rq
;
5080 dequeue_task(rq
, p
, 0);
5082 p
->static_prio
= NICE_TO_PRIO(nice
);
5085 p
->prio
= effective_prio(p
);
5086 delta
= p
->prio
- old_prio
;
5089 enqueue_task(rq
, p
, 0);
5091 * If the task increased its priority or is running and
5092 * lowered its priority, then reschedule its CPU:
5094 if (delta
< 0 || (delta
> 0 && task_running(rq
, p
)))
5095 resched_task(rq
->curr
);
5098 task_rq_unlock(rq
, &flags
);
5100 EXPORT_SYMBOL(set_user_nice
);
5103 * can_nice - check if a task can reduce its nice value
5107 int can_nice(const struct task_struct
*p
, const int nice
)
5109 /* convert nice value [19,-20] to rlimit style value [1,40] */
5110 int nice_rlim
= 20 - nice
;
5112 return (nice_rlim
<= p
->signal
->rlim
[RLIMIT_NICE
].rlim_cur
||
5113 capable(CAP_SYS_NICE
));
5116 #ifdef __ARCH_WANT_SYS_NICE
5119 * sys_nice - change the priority of the current process.
5120 * @increment: priority increment
5122 * sys_setpriority is a more generic, but much slower function that
5123 * does similar things.
5125 asmlinkage
long sys_nice(int increment
)
5130 * Setpriority might change our priority at the same moment.
5131 * We don't have to worry. Conceptually one call occurs first
5132 * and we have a single winner.
5134 if (increment
< -40)
5139 nice
= PRIO_TO_NICE(current
->static_prio
) + increment
;
5145 if (increment
< 0 && !can_nice(current
, nice
))
5148 retval
= security_task_setnice(current
, nice
);
5152 set_user_nice(current
, nice
);
5159 * task_prio - return the priority value of a given task.
5160 * @p: the task in question.
5162 * This is the priority value as seen by users in /proc.
5163 * RT tasks are offset by -200. Normal tasks are centered
5164 * around 0, value goes from -16 to +15.
5166 int task_prio(const struct task_struct
*p
)
5168 return p
->prio
- MAX_RT_PRIO
;
5172 * task_nice - return the nice value of a given task.
5173 * @p: the task in question.
5175 int task_nice(const struct task_struct
*p
)
5177 return TASK_NICE(p
);
5179 EXPORT_SYMBOL(task_nice
);
5182 * idle_cpu - is a given cpu idle currently?
5183 * @cpu: the processor in question.
5185 int idle_cpu(int cpu
)
5187 return cpu_curr(cpu
) == cpu_rq(cpu
)->idle
;
5191 * idle_task - return the idle task for a given cpu.
5192 * @cpu: the processor in question.
5194 struct task_struct
*idle_task(int cpu
)
5196 return cpu_rq(cpu
)->idle
;
5200 * find_process_by_pid - find a process with a matching PID value.
5201 * @pid: the pid in question.
5203 static struct task_struct
*find_process_by_pid(pid_t pid
)
5205 return pid
? find_task_by_vpid(pid
) : current
;
5208 /* Actually do priority change: must hold rq lock. */
5210 __setscheduler(struct rq
*rq
, struct task_struct
*p
, int policy
, int prio
)
5212 BUG_ON(p
->se
.on_rq
);
5215 switch (p
->policy
) {
5219 p
->sched_class
= &fair_sched_class
;
5223 p
->sched_class
= &rt_sched_class
;
5227 p
->rt_priority
= prio
;
5228 p
->normal_prio
= normal_prio(p
);
5229 /* we are holding p->pi_lock already */
5230 p
->prio
= rt_mutex_getprio(p
);
5235 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
5236 * @p: the task in question.
5237 * @policy: new policy.
5238 * @param: structure containing the new RT priority.
5240 * NOTE that the task may be already dead.
5242 int sched_setscheduler(struct task_struct
*p
, int policy
,
5243 struct sched_param
*param
)
5245 int retval
, oldprio
, oldpolicy
= -1, on_rq
, running
;
5246 unsigned long flags
;
5247 const struct sched_class
*prev_class
= p
->sched_class
;
5250 /* may grab non-irq protected spin_locks */
5251 BUG_ON(in_interrupt());
5253 /* double check policy once rq lock held */
5255 policy
= oldpolicy
= p
->policy
;
5256 else if (policy
!= SCHED_FIFO
&& policy
!= SCHED_RR
&&
5257 policy
!= SCHED_NORMAL
&& policy
!= SCHED_BATCH
&&
5258 policy
!= SCHED_IDLE
)
5261 * Valid priorities for SCHED_FIFO and SCHED_RR are
5262 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
5263 * SCHED_BATCH and SCHED_IDLE is 0.
5265 if (param
->sched_priority
< 0 ||
5266 (p
->mm
&& param
->sched_priority
> MAX_USER_RT_PRIO
-1) ||
5267 (!p
->mm
&& param
->sched_priority
> MAX_RT_PRIO
-1))
5269 if (rt_policy(policy
) != (param
->sched_priority
!= 0))
5273 * Allow unprivileged RT tasks to decrease priority:
5275 if (!capable(CAP_SYS_NICE
)) {
5276 if (rt_policy(policy
)) {
5277 unsigned long rlim_rtprio
;
5279 if (!lock_task_sighand(p
, &flags
))
5281 rlim_rtprio
= p
->signal
->rlim
[RLIMIT_RTPRIO
].rlim_cur
;
5282 unlock_task_sighand(p
, &flags
);
5284 /* can't set/change the rt policy */
5285 if (policy
!= p
->policy
&& !rlim_rtprio
)
5288 /* can't increase priority */
5289 if (param
->sched_priority
> p
->rt_priority
&&
5290 param
->sched_priority
> rlim_rtprio
)
5294 * Like positive nice levels, dont allow tasks to
5295 * move out of SCHED_IDLE either:
5297 if (p
->policy
== SCHED_IDLE
&& policy
!= SCHED_IDLE
)
5300 /* can't change other user's priorities */
5301 if ((current
->euid
!= p
->euid
) &&
5302 (current
->euid
!= p
->uid
))
5306 #ifdef CONFIG_RT_GROUP_SCHED
5308 * Do not allow realtime tasks into groups that have no runtime
5311 if (rt_policy(policy
) && task_group(p
)->rt_bandwidth
.rt_runtime
== 0)
5315 retval
= security_task_setscheduler(p
, policy
, param
);
5319 * make sure no PI-waiters arrive (or leave) while we are
5320 * changing the priority of the task:
5322 spin_lock_irqsave(&p
->pi_lock
, flags
);
5324 * To be able to change p->policy safely, the apropriate
5325 * runqueue lock must be held.
5327 rq
= __task_rq_lock(p
);
5328 /* recheck policy now with rq lock held */
5329 if (unlikely(oldpolicy
!= -1 && oldpolicy
!= p
->policy
)) {
5330 policy
= oldpolicy
= -1;
5331 __task_rq_unlock(rq
);
5332 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5335 update_rq_clock(rq
);
5336 on_rq
= p
->se
.on_rq
;
5337 running
= task_current(rq
, p
);
5339 deactivate_task(rq
, p
, 0);
5341 p
->sched_class
->put_prev_task(rq
, p
);
5344 __setscheduler(rq
, p
, policy
, param
->sched_priority
);
5347 p
->sched_class
->set_curr_task(rq
);
5349 activate_task(rq
, p
, 0);
5351 check_class_changed(rq
, p
, prev_class
, oldprio
, running
);
5353 __task_rq_unlock(rq
);
5354 spin_unlock_irqrestore(&p
->pi_lock
, flags
);
5356 rt_mutex_adjust_pi(p
);
5360 EXPORT_SYMBOL_GPL(sched_setscheduler
);
5363 do_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5365 struct sched_param lparam
;
5366 struct task_struct
*p
;
5369 if (!param
|| pid
< 0)
5371 if (copy_from_user(&lparam
, param
, sizeof(struct sched_param
)))
5376 p
= find_process_by_pid(pid
);
5378 retval
= sched_setscheduler(p
, policy
, &lparam
);
5385 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
5386 * @pid: the pid in question.
5387 * @policy: new policy.
5388 * @param: structure containing the new RT priority.
5391 sys_sched_setscheduler(pid_t pid
, int policy
, struct sched_param __user
*param
)
5393 /* negative values for policy are not valid */
5397 return do_sched_setscheduler(pid
, policy
, param
);
5401 * sys_sched_setparam - set/change the RT priority of a thread
5402 * @pid: the pid in question.
5403 * @param: structure containing the new RT priority.
5405 asmlinkage
long sys_sched_setparam(pid_t pid
, struct sched_param __user
*param
)
5407 return do_sched_setscheduler(pid
, -1, param
);
5411 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
5412 * @pid: the pid in question.
5414 asmlinkage
long sys_sched_getscheduler(pid_t pid
)
5416 struct task_struct
*p
;
5423 read_lock(&tasklist_lock
);
5424 p
= find_process_by_pid(pid
);
5426 retval
= security_task_getscheduler(p
);
5430 read_unlock(&tasklist_lock
);
5435 * sys_sched_getscheduler - get the RT priority of a thread
5436 * @pid: the pid in question.
5437 * @param: structure containing the RT priority.
5439 asmlinkage
long sys_sched_getparam(pid_t pid
, struct sched_param __user
*param
)
5441 struct sched_param lp
;
5442 struct task_struct
*p
;
5445 if (!param
|| pid
< 0)
5448 read_lock(&tasklist_lock
);
5449 p
= find_process_by_pid(pid
);
5454 retval
= security_task_getscheduler(p
);
5458 lp
.sched_priority
= p
->rt_priority
;
5459 read_unlock(&tasklist_lock
);
5462 * This one might sleep, we cannot do it with a spinlock held ...
5464 retval
= copy_to_user(param
, &lp
, sizeof(*param
)) ? -EFAULT
: 0;
5469 read_unlock(&tasklist_lock
);
5473 long sched_setaffinity(pid_t pid
, const cpumask_t
*in_mask
)
5475 cpumask_t cpus_allowed
;
5476 cpumask_t new_mask
= *in_mask
;
5477 struct task_struct
*p
;
5481 read_lock(&tasklist_lock
);
5483 p
= find_process_by_pid(pid
);
5485 read_unlock(&tasklist_lock
);
5491 * It is not safe to call set_cpus_allowed with the
5492 * tasklist_lock held. We will bump the task_struct's
5493 * usage count and then drop tasklist_lock.
5496 read_unlock(&tasklist_lock
);
5499 if ((current
->euid
!= p
->euid
) && (current
->euid
!= p
->uid
) &&
5500 !capable(CAP_SYS_NICE
))
5503 retval
= security_task_setscheduler(p
, 0, NULL
);
5507 cpuset_cpus_allowed(p
, &cpus_allowed
);
5508 cpus_and(new_mask
, new_mask
, cpus_allowed
);
5510 retval
= set_cpus_allowed_ptr(p
, &new_mask
);
5513 cpuset_cpus_allowed(p
, &cpus_allowed
);
5514 if (!cpus_subset(new_mask
, cpus_allowed
)) {
5516 * We must have raced with a concurrent cpuset
5517 * update. Just reset the cpus_allowed to the
5518 * cpuset's cpus_allowed
5520 new_mask
= cpus_allowed
;
5530 static int get_user_cpu_mask(unsigned long __user
*user_mask_ptr
, unsigned len
,
5531 cpumask_t
*new_mask
)
5533 if (len
< sizeof(cpumask_t
)) {
5534 memset(new_mask
, 0, sizeof(cpumask_t
));
5535 } else if (len
> sizeof(cpumask_t
)) {
5536 len
= sizeof(cpumask_t
);
5538 return copy_from_user(new_mask
, user_mask_ptr
, len
) ? -EFAULT
: 0;
5542 * sys_sched_setaffinity - set the cpu affinity of a process
5543 * @pid: pid of the process
5544 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5545 * @user_mask_ptr: user-space pointer to the new cpu mask
5547 asmlinkage
long sys_sched_setaffinity(pid_t pid
, unsigned int len
,
5548 unsigned long __user
*user_mask_ptr
)
5553 retval
= get_user_cpu_mask(user_mask_ptr
, len
, &new_mask
);
5557 return sched_setaffinity(pid
, &new_mask
);
5561 * Represents all cpu's present in the system
5562 * In systems capable of hotplug, this map could dynamically grow
5563 * as new cpu's are detected in the system via any platform specific
5564 * method, such as ACPI for e.g.
5567 cpumask_t cpu_present_map __read_mostly
;
5568 EXPORT_SYMBOL(cpu_present_map
);
5571 cpumask_t cpu_online_map __read_mostly
= CPU_MASK_ALL
;
5572 EXPORT_SYMBOL(cpu_online_map
);
5574 cpumask_t cpu_possible_map __read_mostly
= CPU_MASK_ALL
;
5575 EXPORT_SYMBOL(cpu_possible_map
);
5578 long sched_getaffinity(pid_t pid
, cpumask_t
*mask
)
5580 struct task_struct
*p
;
5584 read_lock(&tasklist_lock
);
5587 p
= find_process_by_pid(pid
);
5591 retval
= security_task_getscheduler(p
);
5595 cpus_and(*mask
, p
->cpus_allowed
, cpu_online_map
);
5598 read_unlock(&tasklist_lock
);
5605 * sys_sched_getaffinity - get the cpu affinity of a process
5606 * @pid: pid of the process
5607 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5608 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5610 asmlinkage
long sys_sched_getaffinity(pid_t pid
, unsigned int len
,
5611 unsigned long __user
*user_mask_ptr
)
5616 if (len
< sizeof(cpumask_t
))
5619 ret
= sched_getaffinity(pid
, &mask
);
5623 if (copy_to_user(user_mask_ptr
, &mask
, sizeof(cpumask_t
)))
5626 return sizeof(cpumask_t
);
5630 * sys_sched_yield - yield the current processor to other threads.
5632 * This function yields the current CPU to other tasks. If there are no
5633 * other threads running on this CPU then this function will return.
5635 asmlinkage
long sys_sched_yield(void)
5637 struct rq
*rq
= this_rq_lock();
5639 schedstat_inc(rq
, yld_count
);
5640 current
->sched_class
->yield_task(rq
);
5643 * Since we are going to call schedule() anyway, there's
5644 * no need to preempt or enable interrupts:
5646 __release(rq
->lock
);
5647 spin_release(&rq
->lock
.dep_map
, 1, _THIS_IP_
);
5648 _raw_spin_unlock(&rq
->lock
);
5649 preempt_enable_no_resched();
5656 static void __cond_resched(void)
5658 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5659 __might_sleep(__FILE__
, __LINE__
);
5662 * The BKS might be reacquired before we have dropped
5663 * PREEMPT_ACTIVE, which could trigger a second
5664 * cond_resched() call.
5667 add_preempt_count(PREEMPT_ACTIVE
);
5669 sub_preempt_count(PREEMPT_ACTIVE
);
5670 } while (need_resched());
5673 #if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY)
5674 int __sched
_cond_resched(void)
5676 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE
) &&
5677 system_state
== SYSTEM_RUNNING
) {
5683 EXPORT_SYMBOL(_cond_resched
);
5687 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5688 * call schedule, and on return reacquire the lock.
5690 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
5691 * operations here to prevent schedule() from being called twice (once via
5692 * spin_unlock(), once by hand).
5694 int cond_resched_lock(spinlock_t
*lock
)
5696 int resched
= need_resched() && system_state
== SYSTEM_RUNNING
;
5699 if (spin_needbreak(lock
) || resched
) {
5701 if (resched
&& need_resched())
5710 EXPORT_SYMBOL(cond_resched_lock
);
5712 int __sched
cond_resched_softirq(void)
5714 BUG_ON(!in_softirq());
5716 if (need_resched() && system_state
== SYSTEM_RUNNING
) {
5724 EXPORT_SYMBOL(cond_resched_softirq
);
5727 * yield - yield the current processor to other threads.
5729 * This is a shortcut for kernel-space yielding - it marks the
5730 * thread runnable and calls sys_sched_yield().
5732 void __sched
yield(void)
5734 set_current_state(TASK_RUNNING
);
5737 EXPORT_SYMBOL(yield
);
5740 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
5741 * that process accounting knows that this is a task in IO wait state.
5743 * But don't do that if it is a deliberate, throttling IO wait (this task
5744 * has set its backing_dev_info: the queue against which it should throttle)
5746 void __sched
io_schedule(void)
5748 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5750 delayacct_blkio_start();
5751 atomic_inc(&rq
->nr_iowait
);
5753 atomic_dec(&rq
->nr_iowait
);
5754 delayacct_blkio_end();
5756 EXPORT_SYMBOL(io_schedule
);
5758 long __sched
io_schedule_timeout(long timeout
)
5760 struct rq
*rq
= &__raw_get_cpu_var(runqueues
);
5763 delayacct_blkio_start();
5764 atomic_inc(&rq
->nr_iowait
);
5765 ret
= schedule_timeout(timeout
);
5766 atomic_dec(&rq
->nr_iowait
);
5767 delayacct_blkio_end();
5772 * sys_sched_get_priority_max - return maximum RT priority.
5773 * @policy: scheduling class.
5775 * this syscall returns the maximum rt_priority that can be used
5776 * by a given scheduling class.
5778 asmlinkage
long sys_sched_get_priority_max(int policy
)
5785 ret
= MAX_USER_RT_PRIO
-1;
5797 * sys_sched_get_priority_min - return minimum RT priority.
5798 * @policy: scheduling class.
5800 * this syscall returns the minimum rt_priority that can be used
5801 * by a given scheduling class.
5803 asmlinkage
long sys_sched_get_priority_min(int policy
)
5821 * sys_sched_rr_get_interval - return the default timeslice of a process.
5822 * @pid: pid of the process.
5823 * @interval: userspace pointer to the timeslice value.
5825 * this syscall writes the default timeslice value of a given process
5826 * into the user-space timespec buffer. A value of '0' means infinity.
5829 long sys_sched_rr_get_interval(pid_t pid
, struct timespec __user
*interval
)
5831 struct task_struct
*p
;
5832 unsigned int time_slice
;
5840 read_lock(&tasklist_lock
);
5841 p
= find_process_by_pid(pid
);
5845 retval
= security_task_getscheduler(p
);
5850 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5851 * tasks that are on an otherwise idle runqueue:
5854 if (p
->policy
== SCHED_RR
) {
5855 time_slice
= DEF_TIMESLICE
;
5856 } else if (p
->policy
!= SCHED_FIFO
) {
5857 struct sched_entity
*se
= &p
->se
;
5858 unsigned long flags
;
5861 rq
= task_rq_lock(p
, &flags
);
5862 if (rq
->cfs
.load
.weight
)
5863 time_slice
= NS_TO_JIFFIES(sched_slice(&rq
->cfs
, se
));
5864 task_rq_unlock(rq
, &flags
);
5866 read_unlock(&tasklist_lock
);
5867 jiffies_to_timespec(time_slice
, &t
);
5868 retval
= copy_to_user(interval
, &t
, sizeof(t
)) ? -EFAULT
: 0;
5872 read_unlock(&tasklist_lock
);
5876 static const char stat_nam
[] = "RSDTtZX";
5878 void sched_show_task(struct task_struct
*p
)
5880 unsigned long free
= 0;
5883 state
= p
->state
? __ffs(p
->state
) + 1 : 0;
5884 printk(KERN_INFO
"%-13.13s %c", p
->comm
,
5885 state
< sizeof(stat_nam
) - 1 ? stat_nam
[state
] : '?');
5886 #if BITS_PER_LONG == 32
5887 if (state
== TASK_RUNNING
)
5888 printk(KERN_CONT
" running ");
5890 printk(KERN_CONT
" %08lx ", thread_saved_pc(p
));
5892 if (state
== TASK_RUNNING
)
5893 printk(KERN_CONT
" running task ");
5895 printk(KERN_CONT
" %016lx ", thread_saved_pc(p
));
5897 #ifdef CONFIG_DEBUG_STACK_USAGE
5899 unsigned long *n
= end_of_stack(p
);
5902 free
= (unsigned long)n
- (unsigned long)end_of_stack(p
);
5905 printk(KERN_CONT
"%5lu %5d %6d\n", free
,
5906 task_pid_nr(p
), task_pid_nr(p
->real_parent
));
5908 show_stack(p
, NULL
);
5911 void show_state_filter(unsigned long state_filter
)
5913 struct task_struct
*g
, *p
;
5915 #if BITS_PER_LONG == 32
5917 " task PC stack pid father\n");
5920 " task PC stack pid father\n");
5922 read_lock(&tasklist_lock
);
5923 do_each_thread(g
, p
) {
5925 * reset the NMI-timeout, listing all files on a slow
5926 * console might take alot of time:
5928 touch_nmi_watchdog();
5929 if (!state_filter
|| (p
->state
& state_filter
))
5931 } while_each_thread(g
, p
);
5933 touch_all_softlockup_watchdogs();
5935 #ifdef CONFIG_SCHED_DEBUG
5936 sysrq_sched_debug_show();
5938 read_unlock(&tasklist_lock
);
5940 * Only show locks if all tasks are dumped:
5942 if (state_filter
== -1)
5943 debug_show_all_locks();
5946 void __cpuinit
init_idle_bootup_task(struct task_struct
*idle
)
5948 idle
->sched_class
= &idle_sched_class
;
5952 * init_idle - set up an idle thread for a given CPU
5953 * @idle: task in question
5954 * @cpu: cpu the idle task belongs to
5956 * NOTE: this function does not set the idle thread's NEED_RESCHED
5957 * flag, to make booting more robust.
5959 void __cpuinit
init_idle(struct task_struct
*idle
, int cpu
)
5961 struct rq
*rq
= cpu_rq(cpu
);
5962 unsigned long flags
;
5965 idle
->se
.exec_start
= sched_clock();
5967 idle
->prio
= idle
->normal_prio
= MAX_PRIO
;
5968 idle
->cpus_allowed
= cpumask_of_cpu(cpu
);
5969 __set_task_cpu(idle
, cpu
);
5971 spin_lock_irqsave(&rq
->lock
, flags
);
5972 rq
->curr
= rq
->idle
= idle
;
5973 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5976 spin_unlock_irqrestore(&rq
->lock
, flags
);
5978 /* Set the preempt count _outside_ the spinlocks! */
5979 task_thread_info(idle
)->preempt_count
= 0;
5982 * The idle tasks have their own, simple scheduling class:
5984 idle
->sched_class
= &idle_sched_class
;
5988 * In a system that switches off the HZ timer nohz_cpu_mask
5989 * indicates which cpus entered this state. This is used
5990 * in the rcu update to wait only for active cpus. For system
5991 * which do not switch off the HZ timer nohz_cpu_mask should
5992 * always be CPU_MASK_NONE.
5994 cpumask_t nohz_cpu_mask
= CPU_MASK_NONE
;
5997 * Increase the granularity value when there are more CPUs,
5998 * because with more CPUs the 'effective latency' as visible
5999 * to users decreases. But the relationship is not linear,
6000 * so pick a second-best guess by going with the log2 of the
6003 * This idea comes from the SD scheduler of Con Kolivas:
6005 static inline void sched_init_granularity(void)
6007 unsigned int factor
= 1 + ilog2(num_online_cpus());
6008 const unsigned long limit
= 200000000;
6010 sysctl_sched_min_granularity
*= factor
;
6011 if (sysctl_sched_min_granularity
> limit
)
6012 sysctl_sched_min_granularity
= limit
;
6014 sysctl_sched_latency
*= factor
;
6015 if (sysctl_sched_latency
> limit
)
6016 sysctl_sched_latency
= limit
;
6018 sysctl_sched_wakeup_granularity
*= factor
;
6023 * This is how migration works:
6025 * 1) we queue a struct migration_req structure in the source CPU's
6026 * runqueue and wake up that CPU's migration thread.
6027 * 2) we down() the locked semaphore => thread blocks.
6028 * 3) migration thread wakes up (implicitly it forces the migrated
6029 * thread off the CPU)
6030 * 4) it gets the migration request and checks whether the migrated
6031 * task is still in the wrong runqueue.
6032 * 5) if it's in the wrong runqueue then the migration thread removes
6033 * it and puts it into the right queue.
6034 * 6) migration thread up()s the semaphore.
6035 * 7) we wake up and the migration is done.
6039 * Change a given task's CPU affinity. Migrate the thread to a
6040 * proper CPU and schedule it away if the CPU it's executing on
6041 * is removed from the allowed bitmask.
6043 * NOTE: the caller must have a valid reference to the task, the
6044 * task must not exit() & deallocate itself prematurely. The
6045 * call is not atomic; no spinlocks may be held.
6047 int set_cpus_allowed_ptr(struct task_struct
*p
, const cpumask_t
*new_mask
)
6049 struct migration_req req
;
6050 unsigned long flags
;
6054 rq
= task_rq_lock(p
, &flags
);
6055 if (!cpus_intersects(*new_mask
, cpu_online_map
)) {
6060 if (p
->sched_class
->set_cpus_allowed
)
6061 p
->sched_class
->set_cpus_allowed(p
, new_mask
);
6063 p
->cpus_allowed
= *new_mask
;
6064 p
->rt
.nr_cpus_allowed
= cpus_weight(*new_mask
);
6067 /* Can the task run on the task's current CPU? If so, we're done */
6068 if (cpu_isset(task_cpu(p
), *new_mask
))
6071 if (migrate_task(p
, any_online_cpu(*new_mask
), &req
)) {
6072 /* Need help from migration thread: drop lock and wait. */
6073 task_rq_unlock(rq
, &flags
);
6074 wake_up_process(rq
->migration_thread
);
6075 wait_for_completion(&req
.done
);
6076 tlb_migrate_finish(p
->mm
);
6080 task_rq_unlock(rq
, &flags
);
6084 EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr
);
6087 * Move (not current) task off this cpu, onto dest cpu. We're doing
6088 * this because either it can't run here any more (set_cpus_allowed()
6089 * away from this CPU, or CPU going down), or because we're
6090 * attempting to rebalance this task on exec (sched_exec).
6092 * So we race with normal scheduler movements, but that's OK, as long
6093 * as the task is no longer on this CPU.
6095 * Returns non-zero if task was successfully migrated.
6097 static int __migrate_task(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6099 struct rq
*rq_dest
, *rq_src
;
6102 if (unlikely(cpu_is_offline(dest_cpu
)))
6105 rq_src
= cpu_rq(src_cpu
);
6106 rq_dest
= cpu_rq(dest_cpu
);
6108 double_rq_lock(rq_src
, rq_dest
);
6109 /* Already moved. */
6110 if (task_cpu(p
) != src_cpu
)
6112 /* Affinity changed (again). */
6113 if (!cpu_isset(dest_cpu
, p
->cpus_allowed
))
6116 on_rq
= p
->se
.on_rq
;
6118 deactivate_task(rq_src
, p
, 0);
6120 set_task_cpu(p
, dest_cpu
);
6122 activate_task(rq_dest
, p
, 0);
6123 check_preempt_curr(rq_dest
, p
);
6127 double_rq_unlock(rq_src
, rq_dest
);
6132 * migration_thread - this is a highprio system thread that performs
6133 * thread migration by bumping thread off CPU then 'pushing' onto
6136 static int migration_thread(void *data
)
6138 int cpu
= (long)data
;
6142 BUG_ON(rq
->migration_thread
!= current
);
6144 set_current_state(TASK_INTERRUPTIBLE
);
6145 while (!kthread_should_stop()) {
6146 struct migration_req
*req
;
6147 struct list_head
*head
;
6149 spin_lock_irq(&rq
->lock
);
6151 if (cpu_is_offline(cpu
)) {
6152 spin_unlock_irq(&rq
->lock
);
6156 if (rq
->active_balance
) {
6157 active_load_balance(rq
, cpu
);
6158 rq
->active_balance
= 0;
6161 head
= &rq
->migration_queue
;
6163 if (list_empty(head
)) {
6164 spin_unlock_irq(&rq
->lock
);
6166 set_current_state(TASK_INTERRUPTIBLE
);
6169 req
= list_entry(head
->next
, struct migration_req
, list
);
6170 list_del_init(head
->next
);
6172 spin_unlock(&rq
->lock
);
6173 __migrate_task(req
->task
, cpu
, req
->dest_cpu
);
6176 complete(&req
->done
);
6178 __set_current_state(TASK_RUNNING
);
6182 /* Wait for kthread_stop */
6183 set_current_state(TASK_INTERRUPTIBLE
);
6184 while (!kthread_should_stop()) {
6186 set_current_state(TASK_INTERRUPTIBLE
);
6188 __set_current_state(TASK_RUNNING
);
6192 #ifdef CONFIG_HOTPLUG_CPU
6194 static int __migrate_task_irq(struct task_struct
*p
, int src_cpu
, int dest_cpu
)
6198 local_irq_disable();
6199 ret
= __migrate_task(p
, src_cpu
, dest_cpu
);
6205 * Figure out where task on dead CPU should go, use force if necessary.
6206 * NOTE: interrupts should be disabled by the caller
6208 static void move_task_off_dead_cpu(int dead_cpu
, struct task_struct
*p
)
6210 unsigned long flags
;
6217 mask
= node_to_cpumask(cpu_to_node(dead_cpu
));
6218 cpus_and(mask
, mask
, p
->cpus_allowed
);
6219 dest_cpu
= any_online_cpu(mask
);
6221 /* On any allowed CPU? */
6222 if (dest_cpu
>= nr_cpu_ids
)
6223 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
6225 /* No more Mr. Nice Guy. */
6226 if (dest_cpu
>= nr_cpu_ids
) {
6227 cpumask_t cpus_allowed
;
6229 cpuset_cpus_allowed_locked(p
, &cpus_allowed
);
6231 * Try to stay on the same cpuset, where the
6232 * current cpuset may be a subset of all cpus.
6233 * The cpuset_cpus_allowed_locked() variant of
6234 * cpuset_cpus_allowed() will not block. It must be
6235 * called within calls to cpuset_lock/cpuset_unlock.
6237 rq
= task_rq_lock(p
, &flags
);
6238 p
->cpus_allowed
= cpus_allowed
;
6239 dest_cpu
= any_online_cpu(p
->cpus_allowed
);
6240 task_rq_unlock(rq
, &flags
);
6243 * Don't tell them about moving exiting tasks or
6244 * kernel threads (both mm NULL), since they never
6247 if (p
->mm
&& printk_ratelimit()) {
6248 printk(KERN_INFO
"process %d (%s) no "
6249 "longer affine to cpu%d\n",
6250 task_pid_nr(p
), p
->comm
, dead_cpu
);
6253 } while (!__migrate_task_irq(p
, dead_cpu
, dest_cpu
));
6257 * While a dead CPU has no uninterruptible tasks queued at this point,
6258 * it might still have a nonzero ->nr_uninterruptible counter, because
6259 * for performance reasons the counter is not stricly tracking tasks to
6260 * their home CPUs. So we just add the counter to another CPU's counter,
6261 * to keep the global sum constant after CPU-down:
6263 static void migrate_nr_uninterruptible(struct rq
*rq_src
)
6265 struct rq
*rq_dest
= cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR
));
6266 unsigned long flags
;
6268 local_irq_save(flags
);
6269 double_rq_lock(rq_src
, rq_dest
);
6270 rq_dest
->nr_uninterruptible
+= rq_src
->nr_uninterruptible
;
6271 rq_src
->nr_uninterruptible
= 0;
6272 double_rq_unlock(rq_src
, rq_dest
);
6273 local_irq_restore(flags
);
6276 /* Run through task list and migrate tasks from the dead cpu. */
6277 static void migrate_live_tasks(int src_cpu
)
6279 struct task_struct
*p
, *t
;
6281 read_lock(&tasklist_lock
);
6283 do_each_thread(t
, p
) {
6287 if (task_cpu(p
) == src_cpu
)
6288 move_task_off_dead_cpu(src_cpu
, p
);
6289 } while_each_thread(t
, p
);
6291 read_unlock(&tasklist_lock
);
6295 * Schedules idle task to be the next runnable task on current CPU.
6296 * It does so by boosting its priority to highest possible.
6297 * Used by CPU offline code.
6299 void sched_idle_next(void)
6301 int this_cpu
= smp_processor_id();
6302 struct rq
*rq
= cpu_rq(this_cpu
);
6303 struct task_struct
*p
= rq
->idle
;
6304 unsigned long flags
;
6306 /* cpu has to be offline */
6307 BUG_ON(cpu_online(this_cpu
));
6310 * Strictly not necessary since rest of the CPUs are stopped by now
6311 * and interrupts disabled on the current cpu.
6313 spin_lock_irqsave(&rq
->lock
, flags
);
6315 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6317 update_rq_clock(rq
);
6318 activate_task(rq
, p
, 0);
6320 spin_unlock_irqrestore(&rq
->lock
, flags
);
6324 * Ensures that the idle task is using init_mm right before its cpu goes
6327 void idle_task_exit(void)
6329 struct mm_struct
*mm
= current
->active_mm
;
6331 BUG_ON(cpu_online(smp_processor_id()));
6334 switch_mm(mm
, &init_mm
, current
);
6338 /* called under rq->lock with disabled interrupts */
6339 static void migrate_dead(unsigned int dead_cpu
, struct task_struct
*p
)
6341 struct rq
*rq
= cpu_rq(dead_cpu
);
6343 /* Must be exiting, otherwise would be on tasklist. */
6344 BUG_ON(!p
->exit_state
);
6346 /* Cannot have done final schedule yet: would have vanished. */
6347 BUG_ON(p
->state
== TASK_DEAD
);
6352 * Drop lock around migration; if someone else moves it,
6353 * that's OK. No task can be added to this CPU, so iteration is
6356 spin_unlock_irq(&rq
->lock
);
6357 move_task_off_dead_cpu(dead_cpu
, p
);
6358 spin_lock_irq(&rq
->lock
);
6363 /* release_task() removes task from tasklist, so we won't find dead tasks. */
6364 static void migrate_dead_tasks(unsigned int dead_cpu
)
6366 struct rq
*rq
= cpu_rq(dead_cpu
);
6367 struct task_struct
*next
;
6370 if (!rq
->nr_running
)
6372 update_rq_clock(rq
);
6373 next
= pick_next_task(rq
, rq
->curr
);
6376 migrate_dead(dead_cpu
, next
);
6380 #endif /* CONFIG_HOTPLUG_CPU */
6382 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
6384 static struct ctl_table sd_ctl_dir
[] = {
6386 .procname
= "sched_domain",
6392 static struct ctl_table sd_ctl_root
[] = {
6394 .ctl_name
= CTL_KERN
,
6395 .procname
= "kernel",
6397 .child
= sd_ctl_dir
,
6402 static struct ctl_table
*sd_alloc_ctl_entry(int n
)
6404 struct ctl_table
*entry
=
6405 kcalloc(n
, sizeof(struct ctl_table
), GFP_KERNEL
);
6410 static void sd_free_ctl_entry(struct ctl_table
**tablep
)
6412 struct ctl_table
*entry
;
6415 * In the intermediate directories, both the child directory and
6416 * procname are dynamically allocated and could fail but the mode
6417 * will always be set. In the lowest directory the names are
6418 * static strings and all have proc handlers.
6420 for (entry
= *tablep
; entry
->mode
; entry
++) {
6422 sd_free_ctl_entry(&entry
->child
);
6423 if (entry
->proc_handler
== NULL
)
6424 kfree(entry
->procname
);
6432 set_table_entry(struct ctl_table
*entry
,
6433 const char *procname
, void *data
, int maxlen
,
6434 mode_t mode
, proc_handler
*proc_handler
)
6436 entry
->procname
= procname
;
6438 entry
->maxlen
= maxlen
;
6440 entry
->proc_handler
= proc_handler
;
6443 static struct ctl_table
*
6444 sd_alloc_ctl_domain_table(struct sched_domain
*sd
)
6446 struct ctl_table
*table
= sd_alloc_ctl_entry(12);
6451 set_table_entry(&table
[0], "min_interval", &sd
->min_interval
,
6452 sizeof(long), 0644, proc_doulongvec_minmax
);
6453 set_table_entry(&table
[1], "max_interval", &sd
->max_interval
,
6454 sizeof(long), 0644, proc_doulongvec_minmax
);
6455 set_table_entry(&table
[2], "busy_idx", &sd
->busy_idx
,
6456 sizeof(int), 0644, proc_dointvec_minmax
);
6457 set_table_entry(&table
[3], "idle_idx", &sd
->idle_idx
,
6458 sizeof(int), 0644, proc_dointvec_minmax
);
6459 set_table_entry(&table
[4], "newidle_idx", &sd
->newidle_idx
,
6460 sizeof(int), 0644, proc_dointvec_minmax
);
6461 set_table_entry(&table
[5], "wake_idx", &sd
->wake_idx
,
6462 sizeof(int), 0644, proc_dointvec_minmax
);
6463 set_table_entry(&table
[6], "forkexec_idx", &sd
->forkexec_idx
,
6464 sizeof(int), 0644, proc_dointvec_minmax
);
6465 set_table_entry(&table
[7], "busy_factor", &sd
->busy_factor
,
6466 sizeof(int), 0644, proc_dointvec_minmax
);
6467 set_table_entry(&table
[8], "imbalance_pct", &sd
->imbalance_pct
,
6468 sizeof(int), 0644, proc_dointvec_minmax
);
6469 set_table_entry(&table
[9], "cache_nice_tries",
6470 &sd
->cache_nice_tries
,
6471 sizeof(int), 0644, proc_dointvec_minmax
);
6472 set_table_entry(&table
[10], "flags", &sd
->flags
,
6473 sizeof(int), 0644, proc_dointvec_minmax
);
6474 /* &table[11] is terminator */
6479 static ctl_table
*sd_alloc_ctl_cpu_table(int cpu
)
6481 struct ctl_table
*entry
, *table
;
6482 struct sched_domain
*sd
;
6483 int domain_num
= 0, i
;
6486 for_each_domain(cpu
, sd
)
6488 entry
= table
= sd_alloc_ctl_entry(domain_num
+ 1);
6493 for_each_domain(cpu
, sd
) {
6494 snprintf(buf
, 32, "domain%d", i
);
6495 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6497 entry
->child
= sd_alloc_ctl_domain_table(sd
);
6504 static struct ctl_table_header
*sd_sysctl_header
;
6505 static void register_sched_domain_sysctl(void)
6507 int i
, cpu_num
= num_online_cpus();
6508 struct ctl_table
*entry
= sd_alloc_ctl_entry(cpu_num
+ 1);
6511 WARN_ON(sd_ctl_dir
[0].child
);
6512 sd_ctl_dir
[0].child
= entry
;
6517 for_each_online_cpu(i
) {
6518 snprintf(buf
, 32, "cpu%d", i
);
6519 entry
->procname
= kstrdup(buf
, GFP_KERNEL
);
6521 entry
->child
= sd_alloc_ctl_cpu_table(i
);
6525 WARN_ON(sd_sysctl_header
);
6526 sd_sysctl_header
= register_sysctl_table(sd_ctl_root
);
6529 /* may be called multiple times per register */
6530 static void unregister_sched_domain_sysctl(void)
6532 if (sd_sysctl_header
)
6533 unregister_sysctl_table(sd_sysctl_header
);
6534 sd_sysctl_header
= NULL
;
6535 if (sd_ctl_dir
[0].child
)
6536 sd_free_ctl_entry(&sd_ctl_dir
[0].child
);
6539 static void register_sched_domain_sysctl(void)
6542 static void unregister_sched_domain_sysctl(void)
6548 * migration_call - callback that gets triggered when a CPU is added.
6549 * Here we can start up the necessary migration thread for the new CPU.
6551 static int __cpuinit
6552 migration_call(struct notifier_block
*nfb
, unsigned long action
, void *hcpu
)
6554 struct task_struct
*p
;
6555 int cpu
= (long)hcpu
;
6556 unsigned long flags
;
6561 case CPU_UP_PREPARE
:
6562 case CPU_UP_PREPARE_FROZEN
:
6563 p
= kthread_create(migration_thread
, hcpu
, "migration/%d", cpu
);
6566 kthread_bind(p
, cpu
);
6567 /* Must be high prio: stop_machine expects to yield to it. */
6568 rq
= task_rq_lock(p
, &flags
);
6569 __setscheduler(rq
, p
, SCHED_FIFO
, MAX_RT_PRIO
-1);
6570 task_rq_unlock(rq
, &flags
);
6571 cpu_rq(cpu
)->migration_thread
= p
;
6575 case CPU_ONLINE_FROZEN
:
6576 /* Strictly unnecessary, as first user will wake it. */
6577 wake_up_process(cpu_rq(cpu
)->migration_thread
);
6579 /* Update our root-domain */
6581 spin_lock_irqsave(&rq
->lock
, flags
);
6583 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6584 cpu_set(cpu
, rq
->rd
->online
);
6586 spin_unlock_irqrestore(&rq
->lock
, flags
);
6589 #ifdef CONFIG_HOTPLUG_CPU
6590 case CPU_UP_CANCELED
:
6591 case CPU_UP_CANCELED_FROZEN
:
6592 if (!cpu_rq(cpu
)->migration_thread
)
6594 /* Unbind it from offline cpu so it can run. Fall thru. */
6595 kthread_bind(cpu_rq(cpu
)->migration_thread
,
6596 any_online_cpu(cpu_online_map
));
6597 kthread_stop(cpu_rq(cpu
)->migration_thread
);
6598 cpu_rq(cpu
)->migration_thread
= NULL
;
6602 case CPU_DEAD_FROZEN
:
6603 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
6604 migrate_live_tasks(cpu
);
6606 kthread_stop(rq
->migration_thread
);
6607 rq
->migration_thread
= NULL
;
6608 /* Idle task back to normal (off runqueue, low prio) */
6609 spin_lock_irq(&rq
->lock
);
6610 update_rq_clock(rq
);
6611 deactivate_task(rq
, rq
->idle
, 0);
6612 rq
->idle
->static_prio
= MAX_PRIO
;
6613 __setscheduler(rq
, rq
->idle
, SCHED_NORMAL
, 0);
6614 rq
->idle
->sched_class
= &idle_sched_class
;
6615 migrate_dead_tasks(cpu
);
6616 spin_unlock_irq(&rq
->lock
);
6618 migrate_nr_uninterruptible(rq
);
6619 BUG_ON(rq
->nr_running
!= 0);
6622 * No need to migrate the tasks: it was best-effort if
6623 * they didn't take sched_hotcpu_mutex. Just wake up
6626 spin_lock_irq(&rq
->lock
);
6627 while (!list_empty(&rq
->migration_queue
)) {
6628 struct migration_req
*req
;
6630 req
= list_entry(rq
->migration_queue
.next
,
6631 struct migration_req
, list
);
6632 list_del_init(&req
->list
);
6633 complete(&req
->done
);
6635 spin_unlock_irq(&rq
->lock
);
6639 case CPU_DYING_FROZEN
:
6640 /* Update our root-domain */
6642 spin_lock_irqsave(&rq
->lock
, flags
);
6644 BUG_ON(!cpu_isset(cpu
, rq
->rd
->span
));
6645 cpu_clear(cpu
, rq
->rd
->online
);
6647 spin_unlock_irqrestore(&rq
->lock
, flags
);
6654 /* Register at highest priority so that task migration (migrate_all_tasks)
6655 * happens before everything else.
6657 static struct notifier_block __cpuinitdata migration_notifier
= {
6658 .notifier_call
= migration_call
,
6662 void __init
migration_init(void)
6664 void *cpu
= (void *)(long)smp_processor_id();
6667 /* Start one for the boot CPU: */
6668 err
= migration_call(&migration_notifier
, CPU_UP_PREPARE
, cpu
);
6669 BUG_ON(err
== NOTIFY_BAD
);
6670 migration_call(&migration_notifier
, CPU_ONLINE
, cpu
);
6671 register_cpu_notifier(&migration_notifier
);
6677 #ifdef CONFIG_SCHED_DEBUG
6679 static int sched_domain_debug_one(struct sched_domain
*sd
, int cpu
, int level
,
6680 cpumask_t
*groupmask
)
6682 struct sched_group
*group
= sd
->groups
;
6685 cpulist_scnprintf(str
, sizeof(str
), sd
->span
);
6686 cpus_clear(*groupmask
);
6688 printk(KERN_DEBUG
"%*s domain %d: ", level
, "", level
);
6690 if (!(sd
->flags
& SD_LOAD_BALANCE
)) {
6691 printk("does not load-balance\n");
6693 printk(KERN_ERR
"ERROR: !SD_LOAD_BALANCE domain"
6698 printk(KERN_CONT
"span %s\n", str
);
6700 if (!cpu_isset(cpu
, sd
->span
)) {
6701 printk(KERN_ERR
"ERROR: domain->span does not contain "
6704 if (!cpu_isset(cpu
, group
->cpumask
)) {
6705 printk(KERN_ERR
"ERROR: domain->groups does not contain"
6709 printk(KERN_DEBUG
"%*s groups:", level
+ 1, "");
6713 printk(KERN_ERR
"ERROR: group is NULL\n");
6717 if (!group
->__cpu_power
) {
6718 printk(KERN_CONT
"\n");
6719 printk(KERN_ERR
"ERROR: domain->cpu_power not "
6724 if (!cpus_weight(group
->cpumask
)) {
6725 printk(KERN_CONT
"\n");
6726 printk(KERN_ERR
"ERROR: empty group\n");
6730 if (cpus_intersects(*groupmask
, group
->cpumask
)) {
6731 printk(KERN_CONT
"\n");
6732 printk(KERN_ERR
"ERROR: repeated CPUs\n");
6736 cpus_or(*groupmask
, *groupmask
, group
->cpumask
);
6738 cpulist_scnprintf(str
, sizeof(str
), group
->cpumask
);
6739 printk(KERN_CONT
" %s", str
);
6741 group
= group
->next
;
6742 } while (group
!= sd
->groups
);
6743 printk(KERN_CONT
"\n");
6745 if (!cpus_equal(sd
->span
, *groupmask
))
6746 printk(KERN_ERR
"ERROR: groups don't span domain->span\n");
6748 if (sd
->parent
&& !cpus_subset(*groupmask
, sd
->parent
->span
))
6749 printk(KERN_ERR
"ERROR: parent span is not a superset "
6750 "of domain->span\n");
6754 static void sched_domain_debug(struct sched_domain
*sd
, int cpu
)
6756 cpumask_t
*groupmask
;
6760 printk(KERN_DEBUG
"CPU%d attaching NULL sched-domain.\n", cpu
);
6764 printk(KERN_DEBUG
"CPU%d attaching sched-domain:\n", cpu
);
6766 groupmask
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
6768 printk(KERN_DEBUG
"Cannot load-balance (out of memory)\n");
6773 if (sched_domain_debug_one(sd
, cpu
, level
, groupmask
))
6783 # define sched_domain_debug(sd, cpu) do { } while (0)
6786 static int sd_degenerate(struct sched_domain
*sd
)
6788 if (cpus_weight(sd
->span
) == 1)
6791 /* Following flags need at least 2 groups */
6792 if (sd
->flags
& (SD_LOAD_BALANCE
|
6793 SD_BALANCE_NEWIDLE
|
6797 SD_SHARE_PKG_RESOURCES
)) {
6798 if (sd
->groups
!= sd
->groups
->next
)
6802 /* Following flags don't use groups */
6803 if (sd
->flags
& (SD_WAKE_IDLE
|
6812 sd_parent_degenerate(struct sched_domain
*sd
, struct sched_domain
*parent
)
6814 unsigned long cflags
= sd
->flags
, pflags
= parent
->flags
;
6816 if (sd_degenerate(parent
))
6819 if (!cpus_equal(sd
->span
, parent
->span
))
6822 /* Does parent contain flags not in child? */
6823 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6824 if (cflags
& SD_WAKE_AFFINE
)
6825 pflags
&= ~SD_WAKE_BALANCE
;
6826 /* Flags needing groups don't count if only 1 group in parent */
6827 if (parent
->groups
== parent
->groups
->next
) {
6828 pflags
&= ~(SD_LOAD_BALANCE
|
6829 SD_BALANCE_NEWIDLE
|
6833 SD_SHARE_PKG_RESOURCES
);
6835 if (~cflags
& pflags
)
6841 static void rq_attach_root(struct rq
*rq
, struct root_domain
*rd
)
6843 unsigned long flags
;
6844 const struct sched_class
*class;
6846 spin_lock_irqsave(&rq
->lock
, flags
);
6849 struct root_domain
*old_rd
= rq
->rd
;
6851 for (class = sched_class_highest
; class; class = class->next
) {
6852 if (class->leave_domain
)
6853 class->leave_domain(rq
);
6856 cpu_clear(rq
->cpu
, old_rd
->span
);
6857 cpu_clear(rq
->cpu
, old_rd
->online
);
6859 if (atomic_dec_and_test(&old_rd
->refcount
))
6863 atomic_inc(&rd
->refcount
);
6866 cpu_set(rq
->cpu
, rd
->span
);
6867 if (cpu_isset(rq
->cpu
, cpu_online_map
))
6868 cpu_set(rq
->cpu
, rd
->online
);
6870 for (class = sched_class_highest
; class; class = class->next
) {
6871 if (class->join_domain
)
6872 class->join_domain(rq
);
6875 spin_unlock_irqrestore(&rq
->lock
, flags
);
6878 static void init_rootdomain(struct root_domain
*rd
)
6880 memset(rd
, 0, sizeof(*rd
));
6882 cpus_clear(rd
->span
);
6883 cpus_clear(rd
->online
);
6886 static void init_defrootdomain(void)
6888 init_rootdomain(&def_root_domain
);
6889 atomic_set(&def_root_domain
.refcount
, 1);
6892 static struct root_domain
*alloc_rootdomain(void)
6894 struct root_domain
*rd
;
6896 rd
= kmalloc(sizeof(*rd
), GFP_KERNEL
);
6900 init_rootdomain(rd
);
6906 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
6907 * hold the hotplug lock.
6910 cpu_attach_domain(struct sched_domain
*sd
, struct root_domain
*rd
, int cpu
)
6912 struct rq
*rq
= cpu_rq(cpu
);
6913 struct sched_domain
*tmp
;
6915 /* Remove the sched domains which do not contribute to scheduling. */
6916 for (tmp
= sd
; tmp
; tmp
= tmp
->parent
) {
6917 struct sched_domain
*parent
= tmp
->parent
;
6920 if (sd_parent_degenerate(tmp
, parent
)) {
6921 tmp
->parent
= parent
->parent
;
6923 parent
->parent
->child
= tmp
;
6927 if (sd
&& sd_degenerate(sd
)) {
6933 sched_domain_debug(sd
, cpu
);
6935 rq_attach_root(rq
, rd
);
6936 rcu_assign_pointer(rq
->sd
, sd
);
6939 /* cpus with isolated domains */
6940 static cpumask_t cpu_isolated_map
= CPU_MASK_NONE
;
6942 /* Setup the mask of cpus configured for isolated domains */
6943 static int __init
isolated_cpu_setup(char *str
)
6945 int ints
[NR_CPUS
], i
;
6947 str
= get_options(str
, ARRAY_SIZE(ints
), ints
);
6948 cpus_clear(cpu_isolated_map
);
6949 for (i
= 1; i
<= ints
[0]; i
++)
6950 if (ints
[i
] < NR_CPUS
)
6951 cpu_set(ints
[i
], cpu_isolated_map
);
6955 __setup("isolcpus=", isolated_cpu_setup
);
6958 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6959 * to a function which identifies what group(along with sched group) a CPU
6960 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6961 * (due to the fact that we keep track of groups covered with a cpumask_t).
6963 * init_sched_build_groups will build a circular linked list of the groups
6964 * covered by the given span, and will set each group's ->cpumask correctly,
6965 * and ->cpu_power to 0.
6968 init_sched_build_groups(const cpumask_t
*span
, const cpumask_t
*cpu_map
,
6969 int (*group_fn
)(int cpu
, const cpumask_t
*cpu_map
,
6970 struct sched_group
**sg
,
6971 cpumask_t
*tmpmask
),
6972 cpumask_t
*covered
, cpumask_t
*tmpmask
)
6974 struct sched_group
*first
= NULL
, *last
= NULL
;
6977 cpus_clear(*covered
);
6979 for_each_cpu_mask(i
, *span
) {
6980 struct sched_group
*sg
;
6981 int group
= group_fn(i
, cpu_map
, &sg
, tmpmask
);
6984 if (cpu_isset(i
, *covered
))
6987 cpus_clear(sg
->cpumask
);
6988 sg
->__cpu_power
= 0;
6990 for_each_cpu_mask(j
, *span
) {
6991 if (group_fn(j
, cpu_map
, NULL
, tmpmask
) != group
)
6994 cpu_set(j
, *covered
);
6995 cpu_set(j
, sg
->cpumask
);
7006 #define SD_NODES_PER_DOMAIN 16
7011 * find_next_best_node - find the next node to include in a sched_domain
7012 * @node: node whose sched_domain we're building
7013 * @used_nodes: nodes already in the sched_domain
7015 * Find the next node to include in a given scheduling domain. Simply
7016 * finds the closest node not already in the @used_nodes map.
7018 * Should use nodemask_t.
7020 static int find_next_best_node(int node
, nodemask_t
*used_nodes
)
7022 int i
, n
, val
, min_val
, best_node
= 0;
7026 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7027 /* Start at @node */
7028 n
= (node
+ i
) % MAX_NUMNODES
;
7030 if (!nr_cpus_node(n
))
7033 /* Skip already used nodes */
7034 if (node_isset(n
, *used_nodes
))
7037 /* Simple min distance search */
7038 val
= node_distance(node
, n
);
7040 if (val
< min_val
) {
7046 node_set(best_node
, *used_nodes
);
7051 * sched_domain_node_span - get a cpumask for a node's sched_domain
7052 * @node: node whose cpumask we're constructing
7053 * @span: resulting cpumask
7055 * Given a node, construct a good cpumask for its sched_domain to span. It
7056 * should be one that prevents unnecessary balancing, but also spreads tasks
7059 static void sched_domain_node_span(int node
, cpumask_t
*span
)
7061 nodemask_t used_nodes
;
7062 node_to_cpumask_ptr(nodemask
, node
);
7066 nodes_clear(used_nodes
);
7068 cpus_or(*span
, *span
, *nodemask
);
7069 node_set(node
, used_nodes
);
7071 for (i
= 1; i
< SD_NODES_PER_DOMAIN
; i
++) {
7072 int next_node
= find_next_best_node(node
, &used_nodes
);
7074 node_to_cpumask_ptr_next(nodemask
, next_node
);
7075 cpus_or(*span
, *span
, *nodemask
);
7080 int sched_smt_power_savings
= 0, sched_mc_power_savings
= 0;
7083 * SMT sched-domains:
7085 #ifdef CONFIG_SCHED_SMT
7086 static DEFINE_PER_CPU(struct sched_domain
, cpu_domains
);
7087 static DEFINE_PER_CPU(struct sched_group
, sched_group_cpus
);
7090 cpu_to_cpu_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
7094 *sg
= &per_cpu(sched_group_cpus
, cpu
);
7100 * multi-core sched-domains:
7102 #ifdef CONFIG_SCHED_MC
7103 static DEFINE_PER_CPU(struct sched_domain
, core_domains
);
7104 static DEFINE_PER_CPU(struct sched_group
, sched_group_core
);
7107 #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
7109 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
7114 *mask
= per_cpu(cpu_sibling_map
, cpu
);
7115 cpus_and(*mask
, *mask
, *cpu_map
);
7116 group
= first_cpu(*mask
);
7118 *sg
= &per_cpu(sched_group_core
, group
);
7121 #elif defined(CONFIG_SCHED_MC)
7123 cpu_to_core_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
7127 *sg
= &per_cpu(sched_group_core
, cpu
);
7132 static DEFINE_PER_CPU(struct sched_domain
, phys_domains
);
7133 static DEFINE_PER_CPU(struct sched_group
, sched_group_phys
);
7136 cpu_to_phys_group(int cpu
, const cpumask_t
*cpu_map
, struct sched_group
**sg
,
7140 #ifdef CONFIG_SCHED_MC
7141 *mask
= cpu_coregroup_map(cpu
);
7142 cpus_and(*mask
, *mask
, *cpu_map
);
7143 group
= first_cpu(*mask
);
7144 #elif defined(CONFIG_SCHED_SMT)
7145 *mask
= per_cpu(cpu_sibling_map
, cpu
);
7146 cpus_and(*mask
, *mask
, *cpu_map
);
7147 group
= first_cpu(*mask
);
7152 *sg
= &per_cpu(sched_group_phys
, group
);
7158 * The init_sched_build_groups can't handle what we want to do with node
7159 * groups, so roll our own. Now each node has its own list of groups which
7160 * gets dynamically allocated.
7162 static DEFINE_PER_CPU(struct sched_domain
, node_domains
);
7163 static struct sched_group
***sched_group_nodes_bycpu
;
7165 static DEFINE_PER_CPU(struct sched_domain
, allnodes_domains
);
7166 static DEFINE_PER_CPU(struct sched_group
, sched_group_allnodes
);
7168 static int cpu_to_allnodes_group(int cpu
, const cpumask_t
*cpu_map
,
7169 struct sched_group
**sg
, cpumask_t
*nodemask
)
7173 *nodemask
= node_to_cpumask(cpu_to_node(cpu
));
7174 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7175 group
= first_cpu(*nodemask
);
7178 *sg
= &per_cpu(sched_group_allnodes
, group
);
7182 static void init_numa_sched_groups_power(struct sched_group
*group_head
)
7184 struct sched_group
*sg
= group_head
;
7190 for_each_cpu_mask(j
, sg
->cpumask
) {
7191 struct sched_domain
*sd
;
7193 sd
= &per_cpu(phys_domains
, j
);
7194 if (j
!= first_cpu(sd
->groups
->cpumask
)) {
7196 * Only add "power" once for each
7202 sg_inc_cpu_power(sg
, sd
->groups
->__cpu_power
);
7205 } while (sg
!= group_head
);
7210 /* Free memory allocated for various sched_group structures */
7211 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
7215 for_each_cpu_mask(cpu
, *cpu_map
) {
7216 struct sched_group
**sched_group_nodes
7217 = sched_group_nodes_bycpu
[cpu
];
7219 if (!sched_group_nodes
)
7222 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7223 struct sched_group
*oldsg
, *sg
= sched_group_nodes
[i
];
7225 *nodemask
= node_to_cpumask(i
);
7226 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7227 if (cpus_empty(*nodemask
))
7237 if (oldsg
!= sched_group_nodes
[i
])
7240 kfree(sched_group_nodes
);
7241 sched_group_nodes_bycpu
[cpu
] = NULL
;
7245 static void free_sched_groups(const cpumask_t
*cpu_map
, cpumask_t
*nodemask
)
7251 * Initialize sched groups cpu_power.
7253 * cpu_power indicates the capacity of sched group, which is used while
7254 * distributing the load between different sched groups in a sched domain.
7255 * Typically cpu_power for all the groups in a sched domain will be same unless
7256 * there are asymmetries in the topology. If there are asymmetries, group
7257 * having more cpu_power will pickup more load compared to the group having
7260 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
7261 * the maximum number of tasks a group can handle in the presence of other idle
7262 * or lightly loaded groups in the same sched domain.
7264 static void init_sched_groups_power(int cpu
, struct sched_domain
*sd
)
7266 struct sched_domain
*child
;
7267 struct sched_group
*group
;
7269 WARN_ON(!sd
|| !sd
->groups
);
7271 if (cpu
!= first_cpu(sd
->groups
->cpumask
))
7276 sd
->groups
->__cpu_power
= 0;
7279 * For perf policy, if the groups in child domain share resources
7280 * (for example cores sharing some portions of the cache hierarchy
7281 * or SMT), then set this domain groups cpu_power such that each group
7282 * can handle only one task, when there are other idle groups in the
7283 * same sched domain.
7285 if (!child
|| (!(sd
->flags
& SD_POWERSAVINGS_BALANCE
) &&
7287 (SD_SHARE_CPUPOWER
| SD_SHARE_PKG_RESOURCES
)))) {
7288 sg_inc_cpu_power(sd
->groups
, SCHED_LOAD_SCALE
);
7293 * add cpu_power of each child group to this groups cpu_power
7295 group
= child
->groups
;
7297 sg_inc_cpu_power(sd
->groups
, group
->__cpu_power
);
7298 group
= group
->next
;
7299 } while (group
!= child
->groups
);
7303 * Initializers for schedule domains
7304 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
7307 #define SD_INIT(sd, type) sd_init_##type(sd)
7308 #define SD_INIT_FUNC(type) \
7309 static noinline void sd_init_##type(struct sched_domain *sd) \
7311 memset(sd, 0, sizeof(*sd)); \
7312 *sd = SD_##type##_INIT; \
7313 sd->level = SD_LV_##type; \
7318 SD_INIT_FUNC(ALLNODES
)
7321 #ifdef CONFIG_SCHED_SMT
7322 SD_INIT_FUNC(SIBLING
)
7324 #ifdef CONFIG_SCHED_MC
7329 * To minimize stack usage kmalloc room for cpumasks and share the
7330 * space as the usage in build_sched_domains() dictates. Used only
7331 * if the amount of space is significant.
7334 cpumask_t tmpmask
; /* make this one first */
7337 cpumask_t this_sibling_map
;
7338 cpumask_t this_core_map
;
7340 cpumask_t send_covered
;
7343 cpumask_t domainspan
;
7345 cpumask_t notcovered
;
7350 #define SCHED_CPUMASK_ALLOC 1
7351 #define SCHED_CPUMASK_FREE(v) kfree(v)
7352 #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
7354 #define SCHED_CPUMASK_ALLOC 0
7355 #define SCHED_CPUMASK_FREE(v)
7356 #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
7359 #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
7360 ((unsigned long)(a) + offsetof(struct allmasks, v))
7362 static int default_relax_domain_level
= -1;
7364 static int __init
setup_relax_domain_level(char *str
)
7366 default_relax_domain_level
= simple_strtoul(str
, NULL
, 0);
7369 __setup("relax_domain_level=", setup_relax_domain_level
);
7371 static void set_domain_attribute(struct sched_domain
*sd
,
7372 struct sched_domain_attr
*attr
)
7376 if (!attr
|| attr
->relax_domain_level
< 0) {
7377 if (default_relax_domain_level
< 0)
7380 request
= default_relax_domain_level
;
7382 request
= attr
->relax_domain_level
;
7383 if (request
< sd
->level
) {
7384 /* turn off idle balance on this domain */
7385 sd
->flags
&= ~(SD_WAKE_IDLE
|SD_BALANCE_NEWIDLE
);
7387 /* turn on idle balance on this domain */
7388 sd
->flags
|= (SD_WAKE_IDLE_FAR
|SD_BALANCE_NEWIDLE
);
7393 * Build sched domains for a given set of cpus and attach the sched domains
7394 * to the individual cpus
7396 static int __build_sched_domains(const cpumask_t
*cpu_map
,
7397 struct sched_domain_attr
*attr
)
7400 struct root_domain
*rd
;
7401 SCHED_CPUMASK_DECLARE(allmasks
);
7404 struct sched_group
**sched_group_nodes
= NULL
;
7405 int sd_allnodes
= 0;
7408 * Allocate the per-node list of sched groups
7410 sched_group_nodes
= kcalloc(MAX_NUMNODES
, sizeof(struct sched_group
*),
7412 if (!sched_group_nodes
) {
7413 printk(KERN_WARNING
"Can not alloc sched group node list\n");
7418 rd
= alloc_rootdomain();
7420 printk(KERN_WARNING
"Cannot alloc root domain\n");
7422 kfree(sched_group_nodes
);
7427 #if SCHED_CPUMASK_ALLOC
7428 /* get space for all scratch cpumask variables */
7429 allmasks
= kmalloc(sizeof(*allmasks
), GFP_KERNEL
);
7431 printk(KERN_WARNING
"Cannot alloc cpumask array\n");
7434 kfree(sched_group_nodes
);
7439 tmpmask
= (cpumask_t
*)allmasks
;
7443 sched_group_nodes_bycpu
[first_cpu(*cpu_map
)] = sched_group_nodes
;
7447 * Set up domains for cpus specified by the cpu_map.
7449 for_each_cpu_mask(i
, *cpu_map
) {
7450 struct sched_domain
*sd
= NULL
, *p
;
7451 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7453 *nodemask
= node_to_cpumask(cpu_to_node(i
));
7454 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7457 if (cpus_weight(*cpu_map
) >
7458 SD_NODES_PER_DOMAIN
*cpus_weight(*nodemask
)) {
7459 sd
= &per_cpu(allnodes_domains
, i
);
7460 SD_INIT(sd
, ALLNODES
);
7461 set_domain_attribute(sd
, attr
);
7462 sd
->span
= *cpu_map
;
7463 sd
->first_cpu
= first_cpu(sd
->span
);
7464 cpu_to_allnodes_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7470 sd
= &per_cpu(node_domains
, i
);
7472 set_domain_attribute(sd
, attr
);
7473 sched_domain_node_span(cpu_to_node(i
), &sd
->span
);
7474 sd
->first_cpu
= first_cpu(sd
->span
);
7478 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7482 sd
= &per_cpu(phys_domains
, i
);
7484 set_domain_attribute(sd
, attr
);
7485 sd
->span
= *nodemask
;
7486 sd
->first_cpu
= first_cpu(sd
->span
);
7490 cpu_to_phys_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7492 #ifdef CONFIG_SCHED_MC
7494 sd
= &per_cpu(core_domains
, i
);
7496 set_domain_attribute(sd
, attr
);
7497 sd
->span
= cpu_coregroup_map(i
);
7498 sd
->first_cpu
= first_cpu(sd
->span
);
7499 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7502 cpu_to_core_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7505 #ifdef CONFIG_SCHED_SMT
7507 sd
= &per_cpu(cpu_domains
, i
);
7508 SD_INIT(sd
, SIBLING
);
7509 set_domain_attribute(sd
, attr
);
7510 sd
->span
= per_cpu(cpu_sibling_map
, i
);
7511 sd
->first_cpu
= first_cpu(sd
->span
);
7512 cpus_and(sd
->span
, sd
->span
, *cpu_map
);
7515 cpu_to_cpu_group(i
, cpu_map
, &sd
->groups
, tmpmask
);
7519 #ifdef CONFIG_SCHED_SMT
7520 /* Set up CPU (sibling) groups */
7521 for_each_cpu_mask(i
, *cpu_map
) {
7522 SCHED_CPUMASK_VAR(this_sibling_map
, allmasks
);
7523 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7525 *this_sibling_map
= per_cpu(cpu_sibling_map
, i
);
7526 cpus_and(*this_sibling_map
, *this_sibling_map
, *cpu_map
);
7527 if (i
!= first_cpu(*this_sibling_map
))
7530 init_sched_build_groups(this_sibling_map
, cpu_map
,
7532 send_covered
, tmpmask
);
7536 #ifdef CONFIG_SCHED_MC
7537 /* Set up multi-core groups */
7538 for_each_cpu_mask(i
, *cpu_map
) {
7539 SCHED_CPUMASK_VAR(this_core_map
, allmasks
);
7540 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7542 *this_core_map
= cpu_coregroup_map(i
);
7543 cpus_and(*this_core_map
, *this_core_map
, *cpu_map
);
7544 if (i
!= first_cpu(*this_core_map
))
7547 init_sched_build_groups(this_core_map
, cpu_map
,
7549 send_covered
, tmpmask
);
7553 /* Set up physical groups */
7554 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7555 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7556 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7558 *nodemask
= node_to_cpumask(i
);
7559 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7560 if (cpus_empty(*nodemask
))
7563 init_sched_build_groups(nodemask
, cpu_map
,
7565 send_covered
, tmpmask
);
7569 /* Set up node groups */
7571 SCHED_CPUMASK_VAR(send_covered
, allmasks
);
7573 init_sched_build_groups(cpu_map
, cpu_map
,
7574 &cpu_to_allnodes_group
,
7575 send_covered
, tmpmask
);
7578 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
7579 /* Set up node groups */
7580 struct sched_group
*sg
, *prev
;
7581 SCHED_CPUMASK_VAR(nodemask
, allmasks
);
7582 SCHED_CPUMASK_VAR(domainspan
, allmasks
);
7583 SCHED_CPUMASK_VAR(covered
, allmasks
);
7586 *nodemask
= node_to_cpumask(i
);
7587 cpus_clear(*covered
);
7589 cpus_and(*nodemask
, *nodemask
, *cpu_map
);
7590 if (cpus_empty(*nodemask
)) {
7591 sched_group_nodes
[i
] = NULL
;
7595 sched_domain_node_span(i
, domainspan
);
7596 cpus_and(*domainspan
, *domainspan
, *cpu_map
);
7598 sg
= kmalloc_node(sizeof(struct sched_group
), GFP_KERNEL
, i
);
7600 printk(KERN_WARNING
"Can not alloc domain group for "
7604 sched_group_nodes
[i
] = sg
;
7605 for_each_cpu_mask(j
, *nodemask
) {
7606 struct sched_domain
*sd
;
7608 sd
= &per_cpu(node_domains
, j
);
7611 sg
->__cpu_power
= 0;
7612 sg
->cpumask
= *nodemask
;
7614 cpus_or(*covered
, *covered
, *nodemask
);
7617 for (j
= 0; j
< MAX_NUMNODES
; j
++) {
7618 SCHED_CPUMASK_VAR(notcovered
, allmasks
);
7619 int n
= (i
+ j
) % MAX_NUMNODES
;
7620 node_to_cpumask_ptr(pnodemask
, n
);
7622 cpus_complement(*notcovered
, *covered
);
7623 cpus_and(*tmpmask
, *notcovered
, *cpu_map
);
7624 cpus_and(*tmpmask
, *tmpmask
, *domainspan
);
7625 if (cpus_empty(*tmpmask
))
7628 cpus_and(*tmpmask
, *tmpmask
, *pnodemask
);
7629 if (cpus_empty(*tmpmask
))
7632 sg
= kmalloc_node(sizeof(struct sched_group
),
7636 "Can not alloc domain group for node %d\n", j
);
7639 sg
->__cpu_power
= 0;
7640 sg
->cpumask
= *tmpmask
;
7641 sg
->next
= prev
->next
;
7642 cpus_or(*covered
, *covered
, *tmpmask
);
7649 /* Calculate CPU power for physical packages and nodes */
7650 #ifdef CONFIG_SCHED_SMT
7651 for_each_cpu_mask(i
, *cpu_map
) {
7652 struct sched_domain
*sd
= &per_cpu(cpu_domains
, i
);
7654 init_sched_groups_power(i
, sd
);
7657 #ifdef CONFIG_SCHED_MC
7658 for_each_cpu_mask(i
, *cpu_map
) {
7659 struct sched_domain
*sd
= &per_cpu(core_domains
, i
);
7661 init_sched_groups_power(i
, sd
);
7665 for_each_cpu_mask(i
, *cpu_map
) {
7666 struct sched_domain
*sd
= &per_cpu(phys_domains
, i
);
7668 init_sched_groups_power(i
, sd
);
7672 for (i
= 0; i
< MAX_NUMNODES
; i
++)
7673 init_numa_sched_groups_power(sched_group_nodes
[i
]);
7676 struct sched_group
*sg
;
7678 cpu_to_allnodes_group(first_cpu(*cpu_map
), cpu_map
, &sg
,
7680 init_numa_sched_groups_power(sg
);
7684 /* Attach the domains */
7685 for_each_cpu_mask(i
, *cpu_map
) {
7686 struct sched_domain
*sd
;
7687 #ifdef CONFIG_SCHED_SMT
7688 sd
= &per_cpu(cpu_domains
, i
);
7689 #elif defined(CONFIG_SCHED_MC)
7690 sd
= &per_cpu(core_domains
, i
);
7692 sd
= &per_cpu(phys_domains
, i
);
7694 cpu_attach_domain(sd
, rd
, i
);
7697 SCHED_CPUMASK_FREE((void *)allmasks
);
7702 free_sched_groups(cpu_map
, tmpmask
);
7703 SCHED_CPUMASK_FREE((void *)allmasks
);
7708 static int build_sched_domains(const cpumask_t
*cpu_map
)
7710 return __build_sched_domains(cpu_map
, NULL
);
7713 static cpumask_t
*doms_cur
; /* current sched domains */
7714 static int ndoms_cur
; /* number of sched domains in 'doms_cur' */
7715 static struct sched_domain_attr
*dattr_cur
; /* attribues of custom domains
7719 * Special case: If a kmalloc of a doms_cur partition (array of
7720 * cpumask_t) fails, then fallback to a single sched domain,
7721 * as determined by the single cpumask_t fallback_doms.
7723 static cpumask_t fallback_doms
;
7725 void __attribute__((weak
)) arch_update_cpu_topology(void)
7730 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
7731 * For now this just excludes isolated cpus, but could be used to
7732 * exclude other special cases in the future.
7734 static int arch_init_sched_domains(const cpumask_t
*cpu_map
)
7738 arch_update_cpu_topology();
7740 doms_cur
= kmalloc(sizeof(cpumask_t
), GFP_KERNEL
);
7742 doms_cur
= &fallback_doms
;
7743 cpus_andnot(*doms_cur
, *cpu_map
, cpu_isolated_map
);
7745 err
= build_sched_domains(doms_cur
);
7746 register_sched_domain_sysctl();
7751 static void arch_destroy_sched_domains(const cpumask_t
*cpu_map
,
7754 free_sched_groups(cpu_map
, tmpmask
);
7758 * Detach sched domains from a group of cpus specified in cpu_map
7759 * These cpus will now be attached to the NULL domain
7761 static void detach_destroy_domains(const cpumask_t
*cpu_map
)
7766 unregister_sched_domain_sysctl();
7768 for_each_cpu_mask(i
, *cpu_map
)
7769 cpu_attach_domain(NULL
, &def_root_domain
, i
);
7770 synchronize_sched();
7771 arch_destroy_sched_domains(cpu_map
, &tmpmask
);
7774 /* handle null as "default" */
7775 static int dattrs_equal(struct sched_domain_attr
*cur
, int idx_cur
,
7776 struct sched_domain_attr
*new, int idx_new
)
7778 struct sched_domain_attr tmp
;
7785 return !memcmp(cur
? (cur
+ idx_cur
) : &tmp
,
7786 new ? (new + idx_new
) : &tmp
,
7787 sizeof(struct sched_domain_attr
));
7791 * Partition sched domains as specified by the 'ndoms_new'
7792 * cpumasks in the array doms_new[] of cpumasks. This compares
7793 * doms_new[] to the current sched domain partitioning, doms_cur[].
7794 * It destroys each deleted domain and builds each new domain.
7796 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
7797 * The masks don't intersect (don't overlap.) We should setup one
7798 * sched domain for each mask. CPUs not in any of the cpumasks will
7799 * not be load balanced. If the same cpumask appears both in the
7800 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7803 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7804 * ownership of it and will kfree it when done with it. If the caller
7805 * failed the kmalloc call, then it can pass in doms_new == NULL,
7806 * and partition_sched_domains() will fallback to the single partition
7809 * Call with hotplug lock held
7811 void partition_sched_domains(int ndoms_new
, cpumask_t
*doms_new
,
7812 struct sched_domain_attr
*dattr_new
)
7816 mutex_lock(&sched_domains_mutex
);
7818 /* always unregister in case we don't destroy any domains */
7819 unregister_sched_domain_sysctl();
7821 if (doms_new
== NULL
) {
7823 doms_new
= &fallback_doms
;
7824 cpus_andnot(doms_new
[0], cpu_online_map
, cpu_isolated_map
);
7828 /* Destroy deleted domains */
7829 for (i
= 0; i
< ndoms_cur
; i
++) {
7830 for (j
= 0; j
< ndoms_new
; j
++) {
7831 if (cpus_equal(doms_cur
[i
], doms_new
[j
])
7832 && dattrs_equal(dattr_cur
, i
, dattr_new
, j
))
7835 /* no match - a current sched domain not in new doms_new[] */
7836 detach_destroy_domains(doms_cur
+ i
);
7841 /* Build new domains */
7842 for (i
= 0; i
< ndoms_new
; i
++) {
7843 for (j
= 0; j
< ndoms_cur
; j
++) {
7844 if (cpus_equal(doms_new
[i
], doms_cur
[j
])
7845 && dattrs_equal(dattr_new
, i
, dattr_cur
, j
))
7848 /* no match - add a new doms_new */
7849 __build_sched_domains(doms_new
+ i
,
7850 dattr_new
? dattr_new
+ i
: NULL
);
7855 /* Remember the new sched domains */
7856 if (doms_cur
!= &fallback_doms
)
7858 kfree(dattr_cur
); /* kfree(NULL) is safe */
7859 doms_cur
= doms_new
;
7860 dattr_cur
= dattr_new
;
7861 ndoms_cur
= ndoms_new
;
7863 register_sched_domain_sysctl();
7865 mutex_unlock(&sched_domains_mutex
);
7868 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
7869 int arch_reinit_sched_domains(void)
7874 mutex_lock(&sched_domains_mutex
);
7875 detach_destroy_domains(&cpu_online_map
);
7876 err
= arch_init_sched_domains(&cpu_online_map
);
7877 mutex_unlock(&sched_domains_mutex
);
7883 static ssize_t
sched_power_savings_store(const char *buf
, size_t count
, int smt
)
7887 if (buf
[0] != '0' && buf
[0] != '1')
7891 sched_smt_power_savings
= (buf
[0] == '1');
7893 sched_mc_power_savings
= (buf
[0] == '1');
7895 ret
= arch_reinit_sched_domains();
7897 return ret
? ret
: count
;
7900 #ifdef CONFIG_SCHED_MC
7901 static ssize_t
sched_mc_power_savings_show(struct sys_device
*dev
, char *page
)
7903 return sprintf(page
, "%u\n", sched_mc_power_savings
);
7905 static ssize_t
sched_mc_power_savings_store(struct sys_device
*dev
,
7906 const char *buf
, size_t count
)
7908 return sched_power_savings_store(buf
, count
, 0);
7910 static SYSDEV_ATTR(sched_mc_power_savings
, 0644, sched_mc_power_savings_show
,
7911 sched_mc_power_savings_store
);
7914 #ifdef CONFIG_SCHED_SMT
7915 static ssize_t
sched_smt_power_savings_show(struct sys_device
*dev
, char *page
)
7917 return sprintf(page
, "%u\n", sched_smt_power_savings
);
7919 static ssize_t
sched_smt_power_savings_store(struct sys_device
*dev
,
7920 const char *buf
, size_t count
)
7922 return sched_power_savings_store(buf
, count
, 1);
7924 static SYSDEV_ATTR(sched_smt_power_savings
, 0644, sched_smt_power_savings_show
,
7925 sched_smt_power_savings_store
);
7928 int sched_create_sysfs_power_savings_entries(struct sysdev_class
*cls
)
7932 #ifdef CONFIG_SCHED_SMT
7934 err
= sysfs_create_file(&cls
->kset
.kobj
,
7935 &attr_sched_smt_power_savings
.attr
);
7937 #ifdef CONFIG_SCHED_MC
7938 if (!err
&& mc_capable())
7939 err
= sysfs_create_file(&cls
->kset
.kobj
,
7940 &attr_sched_mc_power_savings
.attr
);
7947 * Force a reinitialization of the sched domains hierarchy. The domains
7948 * and groups cannot be updated in place without racing with the balancing
7949 * code, so we temporarily attach all running cpus to the NULL domain
7950 * which will prevent rebalancing while the sched domains are recalculated.
7952 static int update_sched_domains(struct notifier_block
*nfb
,
7953 unsigned long action
, void *hcpu
)
7956 case CPU_UP_PREPARE
:
7957 case CPU_UP_PREPARE_FROZEN
:
7958 case CPU_DOWN_PREPARE
:
7959 case CPU_DOWN_PREPARE_FROZEN
:
7960 detach_destroy_domains(&cpu_online_map
);
7963 case CPU_UP_CANCELED
:
7964 case CPU_UP_CANCELED_FROZEN
:
7965 case CPU_DOWN_FAILED
:
7966 case CPU_DOWN_FAILED_FROZEN
:
7968 case CPU_ONLINE_FROZEN
:
7970 case CPU_DEAD_FROZEN
:
7972 * Fall through and re-initialise the domains.
7979 /* The hotplug lock is already held by cpu_up/cpu_down */
7980 arch_init_sched_domains(&cpu_online_map
);
7985 void __init
sched_init_smp(void)
7987 cpumask_t non_isolated_cpus
;
7989 #if defined(CONFIG_NUMA)
7990 sched_group_nodes_bycpu
= kzalloc(nr_cpu_ids
* sizeof(void **),
7992 BUG_ON(sched_group_nodes_bycpu
== NULL
);
7995 mutex_lock(&sched_domains_mutex
);
7996 arch_init_sched_domains(&cpu_online_map
);
7997 cpus_andnot(non_isolated_cpus
, cpu_possible_map
, cpu_isolated_map
);
7998 if (cpus_empty(non_isolated_cpus
))
7999 cpu_set(smp_processor_id(), non_isolated_cpus
);
8000 mutex_unlock(&sched_domains_mutex
);
8002 /* XXX: Theoretical race here - CPU may be hotplugged now */
8003 hotcpu_notifier(update_sched_domains
, 0);
8006 /* Move init over to a non-isolated CPU */
8007 if (set_cpus_allowed_ptr(current
, &non_isolated_cpus
) < 0)
8009 sched_init_granularity();
8012 void __init
sched_init_smp(void)
8014 sched_init_granularity();
8016 #endif /* CONFIG_SMP */
8018 int in_sched_functions(unsigned long addr
)
8020 return in_lock_functions(addr
) ||
8021 (addr
>= (unsigned long)__sched_text_start
8022 && addr
< (unsigned long)__sched_text_end
);
8025 static void init_cfs_rq(struct cfs_rq
*cfs_rq
, struct rq
*rq
)
8027 cfs_rq
->tasks_timeline
= RB_ROOT
;
8028 INIT_LIST_HEAD(&cfs_rq
->tasks
);
8029 #ifdef CONFIG_FAIR_GROUP_SCHED
8032 cfs_rq
->min_vruntime
= (u64
)(-(1LL << 20));
8035 static void init_rt_rq(struct rt_rq
*rt_rq
, struct rq
*rq
)
8037 struct rt_prio_array
*array
;
8040 array
= &rt_rq
->active
;
8041 for (i
= 0; i
< MAX_RT_PRIO
; i
++) {
8042 INIT_LIST_HEAD(array
->queue
+ i
);
8043 __clear_bit(i
, array
->bitmap
);
8045 /* delimiter for bitsearch: */
8046 __set_bit(MAX_RT_PRIO
, array
->bitmap
);
8048 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
8049 rt_rq
->highest_prio
= MAX_RT_PRIO
;
8052 rt_rq
->rt_nr_migratory
= 0;
8053 rt_rq
->overloaded
= 0;
8057 rt_rq
->rt_throttled
= 0;
8058 rt_rq
->rt_runtime
= 0;
8059 spin_lock_init(&rt_rq
->rt_runtime_lock
);
8061 #ifdef CONFIG_RT_GROUP_SCHED
8062 rt_rq
->rt_nr_boosted
= 0;
8067 #ifdef CONFIG_FAIR_GROUP_SCHED
8068 static void init_tg_cfs_entry(struct task_group
*tg
, struct cfs_rq
*cfs_rq
,
8069 struct sched_entity
*se
, int cpu
, int add
,
8070 struct sched_entity
*parent
)
8072 struct rq
*rq
= cpu_rq(cpu
);
8073 tg
->cfs_rq
[cpu
] = cfs_rq
;
8074 init_cfs_rq(cfs_rq
, rq
);
8077 list_add(&cfs_rq
->leaf_cfs_rq_list
, &rq
->leaf_cfs_rq_list
);
8080 /* se could be NULL for init_task_group */
8085 se
->cfs_rq
= &rq
->cfs
;
8087 se
->cfs_rq
= parent
->my_q
;
8090 se
->load
.weight
= tg
->shares
;
8091 se
->load
.inv_weight
= 0;
8092 se
->parent
= parent
;
8096 #ifdef CONFIG_RT_GROUP_SCHED
8097 static void init_tg_rt_entry(struct task_group
*tg
, struct rt_rq
*rt_rq
,
8098 struct sched_rt_entity
*rt_se
, int cpu
, int add
,
8099 struct sched_rt_entity
*parent
)
8101 struct rq
*rq
= cpu_rq(cpu
);
8103 tg
->rt_rq
[cpu
] = rt_rq
;
8104 init_rt_rq(rt_rq
, rq
);
8106 rt_rq
->rt_se
= rt_se
;
8107 rt_rq
->rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8109 list_add(&rt_rq
->leaf_rt_rq_list
, &rq
->leaf_rt_rq_list
);
8111 tg
->rt_se
[cpu
] = rt_se
;
8116 rt_se
->rt_rq
= &rq
->rt
;
8118 rt_se
->rt_rq
= parent
->my_q
;
8120 rt_se
->rt_rq
= &rq
->rt
;
8121 rt_se
->my_q
= rt_rq
;
8122 rt_se
->parent
= parent
;
8123 INIT_LIST_HEAD(&rt_se
->run_list
);
8127 void __init
sched_init(void)
8130 unsigned long alloc_size
= 0, ptr
;
8132 #ifdef CONFIG_FAIR_GROUP_SCHED
8133 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8135 #ifdef CONFIG_RT_GROUP_SCHED
8136 alloc_size
+= 2 * nr_cpu_ids
* sizeof(void **);
8138 #ifdef CONFIG_USER_SCHED
8142 * As sched_init() is called before page_alloc is setup,
8143 * we use alloc_bootmem().
8146 ptr
= (unsigned long)alloc_bootmem(alloc_size
);
8148 #ifdef CONFIG_FAIR_GROUP_SCHED
8149 init_task_group
.se
= (struct sched_entity
**)ptr
;
8150 ptr
+= nr_cpu_ids
* sizeof(void **);
8152 init_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8153 ptr
+= nr_cpu_ids
* sizeof(void **);
8155 #ifdef CONFIG_USER_SCHED
8156 root_task_group
.se
= (struct sched_entity
**)ptr
;
8157 ptr
+= nr_cpu_ids
* sizeof(void **);
8159 root_task_group
.cfs_rq
= (struct cfs_rq
**)ptr
;
8160 ptr
+= nr_cpu_ids
* sizeof(void **);
8163 #ifdef CONFIG_RT_GROUP_SCHED
8164 init_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8165 ptr
+= nr_cpu_ids
* sizeof(void **);
8167 init_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8168 ptr
+= nr_cpu_ids
* sizeof(void **);
8170 #ifdef CONFIG_USER_SCHED
8171 root_task_group
.rt_se
= (struct sched_rt_entity
**)ptr
;
8172 ptr
+= nr_cpu_ids
* sizeof(void **);
8174 root_task_group
.rt_rq
= (struct rt_rq
**)ptr
;
8175 ptr
+= nr_cpu_ids
* sizeof(void **);
8182 init_defrootdomain();
8185 init_rt_bandwidth(&def_rt_bandwidth
,
8186 global_rt_period(), global_rt_runtime());
8188 #ifdef CONFIG_RT_GROUP_SCHED
8189 init_rt_bandwidth(&init_task_group
.rt_bandwidth
,
8190 global_rt_period(), global_rt_runtime());
8191 #ifdef CONFIG_USER_SCHED
8192 init_rt_bandwidth(&root_task_group
.rt_bandwidth
,
8193 global_rt_period(), RUNTIME_INF
);
8197 #ifdef CONFIG_GROUP_SCHED
8198 list_add(&init_task_group
.list
, &task_groups
);
8199 INIT_LIST_HEAD(&init_task_group
.children
);
8201 #ifdef CONFIG_USER_SCHED
8202 INIT_LIST_HEAD(&root_task_group
.children
);
8203 init_task_group
.parent
= &root_task_group
;
8204 list_add(&init_task_group
.siblings
, &root_task_group
.children
);
8208 for_each_possible_cpu(i
) {
8212 spin_lock_init(&rq
->lock
);
8213 lockdep_set_class(&rq
->lock
, &rq
->rq_lock_key
);
8216 update_last_tick_seen(rq
);
8217 init_cfs_rq(&rq
->cfs
, rq
);
8218 init_rt_rq(&rq
->rt
, rq
);
8219 #ifdef CONFIG_FAIR_GROUP_SCHED
8220 init_task_group
.shares
= init_task_group_load
;
8221 INIT_LIST_HEAD(&rq
->leaf_cfs_rq_list
);
8222 #ifdef CONFIG_CGROUP_SCHED
8224 * How much cpu bandwidth does init_task_group get?
8226 * In case of task-groups formed thr' the cgroup filesystem, it
8227 * gets 100% of the cpu resources in the system. This overall
8228 * system cpu resource is divided among the tasks of
8229 * init_task_group and its child task-groups in a fair manner,
8230 * based on each entity's (task or task-group's) weight
8231 * (se->load.weight).
8233 * In other words, if init_task_group has 10 tasks of weight
8234 * 1024) and two child groups A0 and A1 (of weight 1024 each),
8235 * then A0's share of the cpu resource is:
8237 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
8239 * We achieve this by letting init_task_group's tasks sit
8240 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
8242 init_tg_cfs_entry(&init_task_group
, &rq
->cfs
, NULL
, i
, 1, NULL
);
8243 #elif defined CONFIG_USER_SCHED
8244 root_task_group
.shares
= NICE_0_LOAD
;
8245 init_tg_cfs_entry(&root_task_group
, &rq
->cfs
, NULL
, i
, 0, NULL
);
8247 * In case of task-groups formed thr' the user id of tasks,
8248 * init_task_group represents tasks belonging to root user.
8249 * Hence it forms a sibling of all subsequent groups formed.
8250 * In this case, init_task_group gets only a fraction of overall
8251 * system cpu resource, based on the weight assigned to root
8252 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
8253 * by letting tasks of init_task_group sit in a separate cfs_rq
8254 * (init_cfs_rq) and having one entity represent this group of
8255 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
8257 init_tg_cfs_entry(&init_task_group
,
8258 &per_cpu(init_cfs_rq
, i
),
8259 &per_cpu(init_sched_entity
, i
), i
, 1,
8260 root_task_group
.se
[i
]);
8263 #endif /* CONFIG_FAIR_GROUP_SCHED */
8265 rq
->rt
.rt_runtime
= def_rt_bandwidth
.rt_runtime
;
8266 #ifdef CONFIG_RT_GROUP_SCHED
8267 INIT_LIST_HEAD(&rq
->leaf_rt_rq_list
);
8268 #ifdef CONFIG_CGROUP_SCHED
8269 init_tg_rt_entry(&init_task_group
, &rq
->rt
, NULL
, i
, 1, NULL
);
8270 #elif defined CONFIG_USER_SCHED
8271 init_tg_rt_entry(&root_task_group
, &rq
->rt
, NULL
, i
, 0, NULL
);
8272 init_tg_rt_entry(&init_task_group
,
8273 &per_cpu(init_rt_rq
, i
),
8274 &per_cpu(init_sched_rt_entity
, i
), i
, 1,
8275 root_task_group
.rt_se
[i
]);
8279 for (j
= 0; j
< CPU_LOAD_IDX_MAX
; j
++)
8280 rq
->cpu_load
[j
] = 0;
8284 rq
->active_balance
= 0;
8285 rq
->next_balance
= jiffies
;
8288 rq
->migration_thread
= NULL
;
8289 INIT_LIST_HEAD(&rq
->migration_queue
);
8290 rq_attach_root(rq
, &def_root_domain
);
8293 atomic_set(&rq
->nr_iowait
, 0);
8296 set_load_weight(&init_task
);
8298 #ifdef CONFIG_PREEMPT_NOTIFIERS
8299 INIT_HLIST_HEAD(&init_task
.preempt_notifiers
);
8303 open_softirq(SCHED_SOFTIRQ
, run_rebalance_domains
, NULL
);
8306 #ifdef CONFIG_RT_MUTEXES
8307 plist_head_init(&init_task
.pi_waiters
, &init_task
.pi_lock
);
8311 * The boot idle thread does lazy MMU switching as well:
8313 atomic_inc(&init_mm
.mm_count
);
8314 enter_lazy_tlb(&init_mm
, current
);
8317 * Make us the idle thread. Technically, schedule() should not be
8318 * called from this thread, however somewhere below it might be,
8319 * but because we are the idle thread, we just pick up running again
8320 * when this runqueue becomes "idle".
8322 init_idle(current
, smp_processor_id());
8324 * During early bootup we pretend to be a normal task:
8326 current
->sched_class
= &fair_sched_class
;
8328 scheduler_running
= 1;
8331 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
8332 void __might_sleep(char *file
, int line
)
8335 static unsigned long prev_jiffy
; /* ratelimiting */
8337 if ((in_atomic() || irqs_disabled()) &&
8338 system_state
== SYSTEM_RUNNING
&& !oops_in_progress
) {
8339 if (time_before(jiffies
, prev_jiffy
+ HZ
) && prev_jiffy
)
8341 prev_jiffy
= jiffies
;
8342 printk(KERN_ERR
"BUG: sleeping function called from invalid"
8343 " context at %s:%d\n", file
, line
);
8344 printk("in_atomic():%d, irqs_disabled():%d\n",
8345 in_atomic(), irqs_disabled());
8346 debug_show_held_locks(current
);
8347 if (irqs_disabled())
8348 print_irqtrace_events(current
);
8353 EXPORT_SYMBOL(__might_sleep
);
8356 #ifdef CONFIG_MAGIC_SYSRQ
8357 static void normalize_task(struct rq
*rq
, struct task_struct
*p
)
8360 update_rq_clock(rq
);
8361 on_rq
= p
->se
.on_rq
;
8363 deactivate_task(rq
, p
, 0);
8364 __setscheduler(rq
, p
, SCHED_NORMAL
, 0);
8366 activate_task(rq
, p
, 0);
8367 resched_task(rq
->curr
);
8371 void normalize_rt_tasks(void)
8373 struct task_struct
*g
, *p
;
8374 unsigned long flags
;
8377 read_lock_irqsave(&tasklist_lock
, flags
);
8378 do_each_thread(g
, p
) {
8380 * Only normalize user tasks:
8385 p
->se
.exec_start
= 0;
8386 #ifdef CONFIG_SCHEDSTATS
8387 p
->se
.wait_start
= 0;
8388 p
->se
.sleep_start
= 0;
8389 p
->se
.block_start
= 0;
8391 task_rq(p
)->clock
= 0;
8395 * Renice negative nice level userspace
8398 if (TASK_NICE(p
) < 0 && p
->mm
)
8399 set_user_nice(p
, 0);
8403 spin_lock(&p
->pi_lock
);
8404 rq
= __task_rq_lock(p
);
8406 normalize_task(rq
, p
);
8408 __task_rq_unlock(rq
);
8409 spin_unlock(&p
->pi_lock
);
8410 } while_each_thread(g
, p
);
8412 read_unlock_irqrestore(&tasklist_lock
, flags
);
8415 #endif /* CONFIG_MAGIC_SYSRQ */
8419 * These functions are only useful for the IA64 MCA handling.
8421 * They can only be called when the whole system has been
8422 * stopped - every CPU needs to be quiescent, and no scheduling
8423 * activity can take place. Using them for anything else would
8424 * be a serious bug, and as a result, they aren't even visible
8425 * under any other configuration.
8429 * curr_task - return the current task for a given cpu.
8430 * @cpu: the processor in question.
8432 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8434 struct task_struct
*curr_task(int cpu
)
8436 return cpu_curr(cpu
);
8440 * set_curr_task - set the current task for a given cpu.
8441 * @cpu: the processor in question.
8442 * @p: the task pointer to set.
8444 * Description: This function must only be used when non-maskable interrupts
8445 * are serviced on a separate stack. It allows the architecture to switch the
8446 * notion of the current task on a cpu in a non-blocking manner. This function
8447 * must be called with all CPU's synchronized, and interrupts disabled, the
8448 * and caller must save the original value of the current task (see
8449 * curr_task() above) and restore that value before reenabling interrupts and
8450 * re-starting the system.
8452 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8454 void set_curr_task(int cpu
, struct task_struct
*p
)
8461 #ifdef CONFIG_FAIR_GROUP_SCHED
8462 static void free_fair_sched_group(struct task_group
*tg
)
8466 for_each_possible_cpu(i
) {
8468 kfree(tg
->cfs_rq
[i
]);
8478 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8480 struct cfs_rq
*cfs_rq
;
8481 struct sched_entity
*se
, *parent_se
;
8485 tg
->cfs_rq
= kzalloc(sizeof(cfs_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8488 tg
->se
= kzalloc(sizeof(se
) * nr_cpu_ids
, GFP_KERNEL
);
8492 tg
->shares
= NICE_0_LOAD
;
8494 for_each_possible_cpu(i
) {
8497 cfs_rq
= kmalloc_node(sizeof(struct cfs_rq
),
8498 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8502 se
= kmalloc_node(sizeof(struct sched_entity
),
8503 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8507 parent_se
= parent
? parent
->se
[i
] : NULL
;
8508 init_tg_cfs_entry(tg
, cfs_rq
, se
, i
, 0, parent_se
);
8517 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8519 list_add_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
,
8520 &cpu_rq(cpu
)->leaf_cfs_rq_list
);
8523 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8525 list_del_rcu(&tg
->cfs_rq
[cpu
]->leaf_cfs_rq_list
);
8528 static inline void free_fair_sched_group(struct task_group
*tg
)
8533 int alloc_fair_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8538 static inline void register_fair_sched_group(struct task_group
*tg
, int cpu
)
8542 static inline void unregister_fair_sched_group(struct task_group
*tg
, int cpu
)
8547 #ifdef CONFIG_RT_GROUP_SCHED
8548 static void free_rt_sched_group(struct task_group
*tg
)
8552 destroy_rt_bandwidth(&tg
->rt_bandwidth
);
8554 for_each_possible_cpu(i
) {
8556 kfree(tg
->rt_rq
[i
]);
8558 kfree(tg
->rt_se
[i
]);
8566 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8568 struct rt_rq
*rt_rq
;
8569 struct sched_rt_entity
*rt_se
, *parent_se
;
8573 tg
->rt_rq
= kzalloc(sizeof(rt_rq
) * nr_cpu_ids
, GFP_KERNEL
);
8576 tg
->rt_se
= kzalloc(sizeof(rt_se
) * nr_cpu_ids
, GFP_KERNEL
);
8580 init_rt_bandwidth(&tg
->rt_bandwidth
,
8581 ktime_to_ns(def_rt_bandwidth
.rt_period
), 0);
8583 for_each_possible_cpu(i
) {
8586 rt_rq
= kmalloc_node(sizeof(struct rt_rq
),
8587 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8591 rt_se
= kmalloc_node(sizeof(struct sched_rt_entity
),
8592 GFP_KERNEL
|__GFP_ZERO
, cpu_to_node(i
));
8596 parent_se
= parent
? parent
->rt_se
[i
] : NULL
;
8597 init_tg_rt_entry(tg
, rt_rq
, rt_se
, i
, 0, parent_se
);
8606 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8608 list_add_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
,
8609 &cpu_rq(cpu
)->leaf_rt_rq_list
);
8612 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8614 list_del_rcu(&tg
->rt_rq
[cpu
]->leaf_rt_rq_list
);
8617 static inline void free_rt_sched_group(struct task_group
*tg
)
8622 int alloc_rt_sched_group(struct task_group
*tg
, struct task_group
*parent
)
8627 static inline void register_rt_sched_group(struct task_group
*tg
, int cpu
)
8631 static inline void unregister_rt_sched_group(struct task_group
*tg
, int cpu
)
8636 #ifdef CONFIG_GROUP_SCHED
8637 static void free_sched_group(struct task_group
*tg
)
8639 free_fair_sched_group(tg
);
8640 free_rt_sched_group(tg
);
8644 /* allocate runqueue etc for a new task group */
8645 struct task_group
*sched_create_group(struct task_group
*parent
)
8647 struct task_group
*tg
;
8648 unsigned long flags
;
8651 tg
= kzalloc(sizeof(*tg
), GFP_KERNEL
);
8653 return ERR_PTR(-ENOMEM
);
8655 if (!alloc_fair_sched_group(tg
, parent
))
8658 if (!alloc_rt_sched_group(tg
, parent
))
8661 spin_lock_irqsave(&task_group_lock
, flags
);
8662 for_each_possible_cpu(i
) {
8663 register_fair_sched_group(tg
, i
);
8664 register_rt_sched_group(tg
, i
);
8666 list_add_rcu(&tg
->list
, &task_groups
);
8668 WARN_ON(!parent
); /* root should already exist */
8670 tg
->parent
= parent
;
8671 list_add_rcu(&tg
->siblings
, &parent
->children
);
8672 INIT_LIST_HEAD(&tg
->children
);
8673 spin_unlock_irqrestore(&task_group_lock
, flags
);
8678 free_sched_group(tg
);
8679 return ERR_PTR(-ENOMEM
);
8682 /* rcu callback to free various structures associated with a task group */
8683 static void free_sched_group_rcu(struct rcu_head
*rhp
)
8685 /* now it should be safe to free those cfs_rqs */
8686 free_sched_group(container_of(rhp
, struct task_group
, rcu
));
8689 /* Destroy runqueue etc associated with a task group */
8690 void sched_destroy_group(struct task_group
*tg
)
8692 unsigned long flags
;
8695 spin_lock_irqsave(&task_group_lock
, flags
);
8696 for_each_possible_cpu(i
) {
8697 unregister_fair_sched_group(tg
, i
);
8698 unregister_rt_sched_group(tg
, i
);
8700 list_del_rcu(&tg
->list
);
8701 list_del_rcu(&tg
->siblings
);
8702 spin_unlock_irqrestore(&task_group_lock
, flags
);
8704 /* wait for possible concurrent references to cfs_rqs complete */
8705 call_rcu(&tg
->rcu
, free_sched_group_rcu
);
8708 /* change task's runqueue when it moves between groups.
8709 * The caller of this function should have put the task in its new group
8710 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8711 * reflect its new group.
8713 void sched_move_task(struct task_struct
*tsk
)
8716 unsigned long flags
;
8719 rq
= task_rq_lock(tsk
, &flags
);
8721 update_rq_clock(rq
);
8723 running
= task_current(rq
, tsk
);
8724 on_rq
= tsk
->se
.on_rq
;
8727 dequeue_task(rq
, tsk
, 0);
8728 if (unlikely(running
))
8729 tsk
->sched_class
->put_prev_task(rq
, tsk
);
8731 set_task_rq(tsk
, task_cpu(tsk
));
8733 #ifdef CONFIG_FAIR_GROUP_SCHED
8734 if (tsk
->sched_class
->moved_group
)
8735 tsk
->sched_class
->moved_group(tsk
);
8738 if (unlikely(running
))
8739 tsk
->sched_class
->set_curr_task(rq
);
8741 enqueue_task(rq
, tsk
, 0);
8743 task_rq_unlock(rq
, &flags
);
8747 #ifdef CONFIG_FAIR_GROUP_SCHED
8748 static void __set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8750 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8755 dequeue_entity(cfs_rq
, se
, 0);
8757 se
->load
.weight
= shares
;
8758 se
->load
.inv_weight
= 0;
8761 enqueue_entity(cfs_rq
, se
, 0);
8764 static void set_se_shares(struct sched_entity
*se
, unsigned long shares
)
8766 struct cfs_rq
*cfs_rq
= se
->cfs_rq
;
8767 struct rq
*rq
= cfs_rq
->rq
;
8768 unsigned long flags
;
8770 spin_lock_irqsave(&rq
->lock
, flags
);
8771 __set_se_shares(se
, shares
);
8772 spin_unlock_irqrestore(&rq
->lock
, flags
);
8775 static DEFINE_MUTEX(shares_mutex
);
8777 int sched_group_set_shares(struct task_group
*tg
, unsigned long shares
)
8780 unsigned long flags
;
8783 * We can't change the weight of the root cgroup.
8789 * A weight of 0 or 1 can cause arithmetics problems.
8790 * (The default weight is 1024 - so there's no practical
8791 * limitation from this.)
8793 if (shares
< MIN_SHARES
)
8794 shares
= MIN_SHARES
;
8796 mutex_lock(&shares_mutex
);
8797 if (tg
->shares
== shares
)
8800 spin_lock_irqsave(&task_group_lock
, flags
);
8801 for_each_possible_cpu(i
)
8802 unregister_fair_sched_group(tg
, i
);
8803 list_del_rcu(&tg
->siblings
);
8804 spin_unlock_irqrestore(&task_group_lock
, flags
);
8806 /* wait for any ongoing reference to this group to finish */
8807 synchronize_sched();
8810 * Now we are free to modify the group's share on each cpu
8811 * w/o tripping rebalance_share or load_balance_fair.
8813 tg
->shares
= shares
;
8814 for_each_possible_cpu(i
) {
8818 cfs_rq_set_shares(tg
->cfs_rq
[i
], 0);
8819 set_se_shares(tg
->se
[i
], shares
/nr_cpu_ids
);
8823 * Enable load balance activity on this group, by inserting it back on
8824 * each cpu's rq->leaf_cfs_rq_list.
8826 spin_lock_irqsave(&task_group_lock
, flags
);
8827 for_each_possible_cpu(i
)
8828 register_fair_sched_group(tg
, i
);
8829 list_add_rcu(&tg
->siblings
, &tg
->parent
->children
);
8830 spin_unlock_irqrestore(&task_group_lock
, flags
);
8832 mutex_unlock(&shares_mutex
);
8836 unsigned long sched_group_shares(struct task_group
*tg
)
8842 #ifdef CONFIG_RT_GROUP_SCHED
8844 * Ensure that the real time constraints are schedulable.
8846 static DEFINE_MUTEX(rt_constraints_mutex
);
8848 static unsigned long to_ratio(u64 period
, u64 runtime
)
8850 if (runtime
== RUNTIME_INF
)
8853 return div64_u64(runtime
<< 16, period
);
8856 #ifdef CONFIG_CGROUP_SCHED
8857 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8859 struct task_group
*tgi
, *parent
= tg
->parent
;
8860 unsigned long total
= 0;
8863 if (global_rt_period() < period
)
8866 return to_ratio(period
, runtime
) <
8867 to_ratio(global_rt_period(), global_rt_runtime());
8870 if (ktime_to_ns(parent
->rt_bandwidth
.rt_period
) < period
)
8874 list_for_each_entry_rcu(tgi
, &parent
->children
, siblings
) {
8878 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8879 tgi
->rt_bandwidth
.rt_runtime
);
8883 return total
+ to_ratio(period
, runtime
) <
8884 to_ratio(ktime_to_ns(parent
->rt_bandwidth
.rt_period
),
8885 parent
->rt_bandwidth
.rt_runtime
);
8887 #elif defined CONFIG_USER_SCHED
8888 static int __rt_schedulable(struct task_group
*tg
, u64 period
, u64 runtime
)
8890 struct task_group
*tgi
;
8891 unsigned long total
= 0;
8892 unsigned long global_ratio
=
8893 to_ratio(global_rt_period(), global_rt_runtime());
8896 list_for_each_entry_rcu(tgi
, &task_groups
, list
) {
8900 total
+= to_ratio(ktime_to_ns(tgi
->rt_bandwidth
.rt_period
),
8901 tgi
->rt_bandwidth
.rt_runtime
);
8905 return total
+ to_ratio(period
, runtime
) < global_ratio
;
8909 /* Must be called with tasklist_lock held */
8910 static inline int tg_has_rt_tasks(struct task_group
*tg
)
8912 struct task_struct
*g
, *p
;
8913 do_each_thread(g
, p
) {
8914 if (rt_task(p
) && rt_rq_of_se(&p
->rt
)->tg
== tg
)
8916 } while_each_thread(g
, p
);
8920 static int tg_set_bandwidth(struct task_group
*tg
,
8921 u64 rt_period
, u64 rt_runtime
)
8925 mutex_lock(&rt_constraints_mutex
);
8926 read_lock(&tasklist_lock
);
8927 if (rt_runtime
== 0 && tg_has_rt_tasks(tg
)) {
8931 if (!__rt_schedulable(tg
, rt_period
, rt_runtime
)) {
8936 spin_lock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8937 tg
->rt_bandwidth
.rt_period
= ns_to_ktime(rt_period
);
8938 tg
->rt_bandwidth
.rt_runtime
= rt_runtime
;
8940 for_each_possible_cpu(i
) {
8941 struct rt_rq
*rt_rq
= tg
->rt_rq
[i
];
8943 spin_lock(&rt_rq
->rt_runtime_lock
);
8944 rt_rq
->rt_runtime
= rt_runtime
;
8945 spin_unlock(&rt_rq
->rt_runtime_lock
);
8947 spin_unlock_irq(&tg
->rt_bandwidth
.rt_runtime_lock
);
8949 read_unlock(&tasklist_lock
);
8950 mutex_unlock(&rt_constraints_mutex
);
8955 int sched_group_set_rt_runtime(struct task_group
*tg
, long rt_runtime_us
)
8957 u64 rt_runtime
, rt_period
;
8959 rt_period
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8960 rt_runtime
= (u64
)rt_runtime_us
* NSEC_PER_USEC
;
8961 if (rt_runtime_us
< 0)
8962 rt_runtime
= RUNTIME_INF
;
8964 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8967 long sched_group_rt_runtime(struct task_group
*tg
)
8971 if (tg
->rt_bandwidth
.rt_runtime
== RUNTIME_INF
)
8974 rt_runtime_us
= tg
->rt_bandwidth
.rt_runtime
;
8975 do_div(rt_runtime_us
, NSEC_PER_USEC
);
8976 return rt_runtime_us
;
8979 int sched_group_set_rt_period(struct task_group
*tg
, long rt_period_us
)
8981 u64 rt_runtime
, rt_period
;
8983 rt_period
= (u64
)rt_period_us
* NSEC_PER_USEC
;
8984 rt_runtime
= tg
->rt_bandwidth
.rt_runtime
;
8986 return tg_set_bandwidth(tg
, rt_period
, rt_runtime
);
8989 long sched_group_rt_period(struct task_group
*tg
)
8993 rt_period_us
= ktime_to_ns(tg
->rt_bandwidth
.rt_period
);
8994 do_div(rt_period_us
, NSEC_PER_USEC
);
8995 return rt_period_us
;
8998 static int sched_rt_global_constraints(void)
9002 mutex_lock(&rt_constraints_mutex
);
9003 if (!__rt_schedulable(NULL
, 1, 0))
9005 mutex_unlock(&rt_constraints_mutex
);
9010 static int sched_rt_global_constraints(void)
9012 unsigned long flags
;
9015 spin_lock_irqsave(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9016 for_each_possible_cpu(i
) {
9017 struct rt_rq
*rt_rq
= &cpu_rq(i
)->rt
;
9019 spin_lock(&rt_rq
->rt_runtime_lock
);
9020 rt_rq
->rt_runtime
= global_rt_runtime();
9021 spin_unlock(&rt_rq
->rt_runtime_lock
);
9023 spin_unlock_irqrestore(&def_rt_bandwidth
.rt_runtime_lock
, flags
);
9029 int sched_rt_handler(struct ctl_table
*table
, int write
,
9030 struct file
*filp
, void __user
*buffer
, size_t *lenp
,
9034 int old_period
, old_runtime
;
9035 static DEFINE_MUTEX(mutex
);
9038 old_period
= sysctl_sched_rt_period
;
9039 old_runtime
= sysctl_sched_rt_runtime
;
9041 ret
= proc_dointvec(table
, write
, filp
, buffer
, lenp
, ppos
);
9043 if (!ret
&& write
) {
9044 ret
= sched_rt_global_constraints();
9046 sysctl_sched_rt_period
= old_period
;
9047 sysctl_sched_rt_runtime
= old_runtime
;
9049 def_rt_bandwidth
.rt_runtime
= global_rt_runtime();
9050 def_rt_bandwidth
.rt_period
=
9051 ns_to_ktime(global_rt_period());
9054 mutex_unlock(&mutex
);
9059 #ifdef CONFIG_CGROUP_SCHED
9061 /* return corresponding task_group object of a cgroup */
9062 static inline struct task_group
*cgroup_tg(struct cgroup
*cgrp
)
9064 return container_of(cgroup_subsys_state(cgrp
, cpu_cgroup_subsys_id
),
9065 struct task_group
, css
);
9068 static struct cgroup_subsys_state
*
9069 cpu_cgroup_create(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9071 struct task_group
*tg
, *parent
;
9073 if (!cgrp
->parent
) {
9074 /* This is early initialization for the top cgroup */
9075 init_task_group
.css
.cgroup
= cgrp
;
9076 return &init_task_group
.css
;
9079 parent
= cgroup_tg(cgrp
->parent
);
9080 tg
= sched_create_group(parent
);
9082 return ERR_PTR(-ENOMEM
);
9084 /* Bind the cgroup to task_group object we just created */
9085 tg
->css
.cgroup
= cgrp
;
9091 cpu_cgroup_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9093 struct task_group
*tg
= cgroup_tg(cgrp
);
9095 sched_destroy_group(tg
);
9099 cpu_cgroup_can_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9100 struct task_struct
*tsk
)
9102 #ifdef CONFIG_RT_GROUP_SCHED
9103 /* Don't accept realtime tasks when there is no way for them to run */
9104 if (rt_task(tsk
) && cgroup_tg(cgrp
)->rt_bandwidth
.rt_runtime
== 0)
9107 /* We don't support RT-tasks being in separate groups */
9108 if (tsk
->sched_class
!= &fair_sched_class
)
9116 cpu_cgroup_attach(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
,
9117 struct cgroup
*old_cont
, struct task_struct
*tsk
)
9119 sched_move_task(tsk
);
9122 #ifdef CONFIG_FAIR_GROUP_SCHED
9123 static int cpu_shares_write_u64(struct cgroup
*cgrp
, struct cftype
*cftype
,
9126 return sched_group_set_shares(cgroup_tg(cgrp
), shareval
);
9129 static u64
cpu_shares_read_u64(struct cgroup
*cgrp
, struct cftype
*cft
)
9131 struct task_group
*tg
= cgroup_tg(cgrp
);
9133 return (u64
) tg
->shares
;
9137 #ifdef CONFIG_RT_GROUP_SCHED
9138 static ssize_t
cpu_rt_runtime_write(struct cgroup
*cgrp
, struct cftype
*cft
,
9141 return sched_group_set_rt_runtime(cgroup_tg(cgrp
), val
);
9144 static s64
cpu_rt_runtime_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9146 return sched_group_rt_runtime(cgroup_tg(cgrp
));
9149 static int cpu_rt_period_write_uint(struct cgroup
*cgrp
, struct cftype
*cftype
,
9152 return sched_group_set_rt_period(cgroup_tg(cgrp
), rt_period_us
);
9155 static u64
cpu_rt_period_read_uint(struct cgroup
*cgrp
, struct cftype
*cft
)
9157 return sched_group_rt_period(cgroup_tg(cgrp
));
9161 static struct cftype cpu_files
[] = {
9162 #ifdef CONFIG_FAIR_GROUP_SCHED
9165 .read_u64
= cpu_shares_read_u64
,
9166 .write_u64
= cpu_shares_write_u64
,
9169 #ifdef CONFIG_RT_GROUP_SCHED
9171 .name
= "rt_runtime_us",
9172 .read_s64
= cpu_rt_runtime_read
,
9173 .write_s64
= cpu_rt_runtime_write
,
9176 .name
= "rt_period_us",
9177 .read_u64
= cpu_rt_period_read_uint
,
9178 .write_u64
= cpu_rt_period_write_uint
,
9183 static int cpu_cgroup_populate(struct cgroup_subsys
*ss
, struct cgroup
*cont
)
9185 return cgroup_add_files(cont
, ss
, cpu_files
, ARRAY_SIZE(cpu_files
));
9188 struct cgroup_subsys cpu_cgroup_subsys
= {
9190 .create
= cpu_cgroup_create
,
9191 .destroy
= cpu_cgroup_destroy
,
9192 .can_attach
= cpu_cgroup_can_attach
,
9193 .attach
= cpu_cgroup_attach
,
9194 .populate
= cpu_cgroup_populate
,
9195 .subsys_id
= cpu_cgroup_subsys_id
,
9199 #endif /* CONFIG_CGROUP_SCHED */
9201 #ifdef CONFIG_CGROUP_CPUACCT
9204 * CPU accounting code for task groups.
9206 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
9207 * (balbir@in.ibm.com).
9210 /* track cpu usage of a group of tasks */
9212 struct cgroup_subsys_state css
;
9213 /* cpuusage holds pointer to a u64-type object on every cpu */
9217 struct cgroup_subsys cpuacct_subsys
;
9219 /* return cpu accounting group corresponding to this container */
9220 static inline struct cpuacct
*cgroup_ca(struct cgroup
*cgrp
)
9222 return container_of(cgroup_subsys_state(cgrp
, cpuacct_subsys_id
),
9223 struct cpuacct
, css
);
9226 /* return cpu accounting group to which this task belongs */
9227 static inline struct cpuacct
*task_ca(struct task_struct
*tsk
)
9229 return container_of(task_subsys_state(tsk
, cpuacct_subsys_id
),
9230 struct cpuacct
, css
);
9233 /* create a new cpu accounting group */
9234 static struct cgroup_subsys_state
*cpuacct_create(
9235 struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9237 struct cpuacct
*ca
= kzalloc(sizeof(*ca
), GFP_KERNEL
);
9240 return ERR_PTR(-ENOMEM
);
9242 ca
->cpuusage
= alloc_percpu(u64
);
9243 if (!ca
->cpuusage
) {
9245 return ERR_PTR(-ENOMEM
);
9251 /* destroy an existing cpu accounting group */
9253 cpuacct_destroy(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9255 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9257 free_percpu(ca
->cpuusage
);
9261 /* return total cpu usage (in nanoseconds) of a group */
9262 static u64
cpuusage_read(struct cgroup
*cgrp
, struct cftype
*cft
)
9264 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9265 u64 totalcpuusage
= 0;
9268 for_each_possible_cpu(i
) {
9269 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
9272 * Take rq->lock to make 64-bit addition safe on 32-bit
9275 spin_lock_irq(&cpu_rq(i
)->lock
);
9276 totalcpuusage
+= *cpuusage
;
9277 spin_unlock_irq(&cpu_rq(i
)->lock
);
9280 return totalcpuusage
;
9283 static int cpuusage_write(struct cgroup
*cgrp
, struct cftype
*cftype
,
9286 struct cpuacct
*ca
= cgroup_ca(cgrp
);
9295 for_each_possible_cpu(i
) {
9296 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, i
);
9298 spin_lock_irq(&cpu_rq(i
)->lock
);
9300 spin_unlock_irq(&cpu_rq(i
)->lock
);
9306 static struct cftype files
[] = {
9309 .read_u64
= cpuusage_read
,
9310 .write_u64
= cpuusage_write
,
9314 static int cpuacct_populate(struct cgroup_subsys
*ss
, struct cgroup
*cgrp
)
9316 return cgroup_add_files(cgrp
, ss
, files
, ARRAY_SIZE(files
));
9320 * charge this task's execution time to its accounting group.
9322 * called with rq->lock held.
9324 static void cpuacct_charge(struct task_struct
*tsk
, u64 cputime
)
9328 if (!cpuacct_subsys
.active
)
9333 u64
*cpuusage
= percpu_ptr(ca
->cpuusage
, task_cpu(tsk
));
9335 *cpuusage
+= cputime
;
9339 struct cgroup_subsys cpuacct_subsys
= {
9341 .create
= cpuacct_create
,
9342 .destroy
= cpuacct_destroy
,
9343 .populate
= cpuacct_populate
,
9344 .subsys_id
= cpuacct_subsys_id
,
9346 #endif /* CONFIG_CGROUP_CPUACCT */